ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Electron microscopy  (160)
  • Calcium  (98)
  • Biology
  • Inorganic Chemistry
  • LUNAR AND PLANETARY EXPLORATION
  • Springer  (258)
  • 1980-1984  (258)
  • 1930-1934
Collection
Keywords
Publisher
Years
Year
  • 1
    Electronic Resource
    Electronic Resource
    Effects of weight loss on serum 1,25-(OH)2-vitamin D concentrations in adults: A preliminary report (1984)
    Springer
    Calcified tissue international 36 (1984), S. 139-144 
    Details
    ISSN: 1432-0827
    Keywords: 1,25(OH)2-vitamin D ; Weight loss ; Phosphate ; Calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary During a review of 42 metabolic studies in healthy women and men we observed that serum 1,25-(OH)2-D concentrations were directly correlated to the observed daily changes in body weight (r=0.68;P〈0.001) and to caloric intake/kg/day (r=0.39;P=0.01). These relationships could not be accounted for by related and physiologically expected changes in serum Ca or iPTH concentrations. However, serum 1,25-(OH)2-D concentrations were observed to be inversely correlated to serum PO4 levels (r=−0.44;P=0.004). In addition, serum PO4 levels were inversely correlated to the daily changes in body weight (r=−0.40;P=0.009). Since dietary sodium intake averaged 142 mmol/day, it is unlikely that the observed changes in weight were the result of changes in salt and water balance. Thus it seems reasonable to speculate that serum 1,25-(OH)2-D concentrations may vary directly with energy balance, as reflected by changes in body weight. This effect may be mediated by alterations in PO4 metabolism. The accurate assessment of serum 1,25-(OH)2-D levels thus appears to require several measurements over time periods during which body weight is stable.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02405309
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Electromagnetic modulation of biological processes: Influence of culture media and significance of methodology in the Ca-uptake by embryonal chick tibiain vitro (1984)
    Springer
    Calcified tissue international 36 (1984), S. 167-174 
    Details
    ISSN: 1432-0827
    Keywords: Electromagnetic field ; Bicarbonate ; Phosphate ; Calcium ; Fluoride ; Osteogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The present studies are aimed at establishing molecular correlations in the interaction of very low frequency electromagnetic fields with biological systems. Ca-uptake by chick embryo tibia rudiment in short-term culture was a useful model. Tibiae of 8- to 10-day-old chick embryos were incubated 60 min in simplified culture media in the presence of45Ca at 37.5±0.5°C either inside or outside pulsating electromagnetic fields. Radioactivity count in the medium was the most accurate method for determining Ca-uptake by the rudiment. The effect of the fields on the Ca-uptake depended markedly on the chemical composition of the culture medium: bicarbonate was indispensable; glucose or sucrose was important; phosphate was potentiating; ethanol, Mg2+, and NaF were stimulating. The field had no effect in (a) blank medium without tibia, (b) tibiae that had been altered by fixation with aqueous glutaraldehyde, (c) nonliving artificial systems endowed with great or small ion sorption capacity. The unique bicarbonate effect with living systems and the passive behavior of nonliving ion sorbing systems prompt the suggestion that the electromagnetic field probably couples with specific processes, such as a bicarbonate-dependent Ca2+ ATPase and the active ion transport, at the cell membrane level. The molecular mechanisms remain to be established.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02405313
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Benzo(B)Thiophene-2-Carboxylic acid: Calcium uptake and cyclic AMP production in isolated bone cells (1984)
    Springer
    Calcified tissue international 36 (1984), S. 194-199 
    Details
    ISSN: 1432-0827
    Keywords: Benzo(B)Thiophene-2-Carboxylic Acid ; Bone cells ; Calcium ; Cyclic AMP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The purpose of the present study was to investigate the mechanism of action on bone of Benzo(B)Thiophene-2-Carboxylic Acid (BL-5583). BL-5583, at a dose range of 0.01–100 µg/ml, inhibited spontaneous as well as A23187 and PTH-induced bone resorption in tissue culture. This compound also decreased calcium uptake in both osteoclastic and osteoblastic enriched bone cell populations obtained by sequential collagenase digestion of 1–2 day newborn rat calvariae. The decrease occurred after a 5 min. incubation with45Ca and BL-5583. The effective dose range was 0.01–100 µg/ml. No effect on leucine incorporation or lactic acid production by bone cells was observed. BL-5583 also induced a transient decrease in calcium uptake in skin cells isolated from fetal rats by collagenase digestion, suggesting a lack of tissue specificity for this compound. No effect on cyclic AMP in isolated bone cells was observed with the same dose range that produced a calcium effect.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02405317
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Effects of vitamin D and parathyroid hormone on cyclic AMP production by bone cells isolated from rat calvariae (1984)
    Springer
    Calcified tissue international 36 (1984), S. 320-326 
    Details
    ISSN: 1432-0827
    Keywords: Calcium ; Vitamin D deficiency ; 1,25(OH)2D3 ; Parathyroidectomy ; Parathyroid hormone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Studies presented here were designed to investigate further the basis for an impaired cAMP response to parathyroid hormone (PTH) in osteoblastlike calvarial bone cells isolated from vitamin D-deficient rat pups. The goal was to perturb Ca, PTH, and vitamin Din vivo in order to see which factors might be responsible for the impairedin vitro bone cell cAMP response. Pups either were parathyroidectomized (PTX) 3–5 days, implanted with osmotic minipumps delivering high doses of PTH, given repeated, high doses of 1,25(OH)2D3, or were D-deficient (-D, i.e., born and suckled by D-deficient mothers). Osteoblastlike bone cells, isolated by sequential enzyme digestion and centrifugation, were exposed to PTH for 5 min in the presence of a phosphodiesterase inhibitor. In bone cells isolated from -D rat pups, both basal and PTH-induced cAMP accumulation were significantly lower than in +D bone cells. Earlier, we had shown that two daily injections of -D pups with 50 ng 1,25(OH)2D3 restores this reduced bone cAMP response of -D pups toward normal. In the present study, neither basal nor PTH-induced bone cell cAMP accumulation was affected by subjecting D-replete pups to PTX, PTH infusion, or repeated high doses of 1,25(OH)2D3 despite the fact that each treatment markedly changed serum Ca or serum immunoreactive PTH. The results indicate that the impaired bone cell cAMP response seen in -D pups is not a direct result of chronic hypocalcemia and that the “heterologous desensitization” seenin vitro with added 1,25(OH)2D3 could not be duplicated byin vivo treatment of +D pups with supraphysiologic doses of 1,25(OH)2D3. Finally the lack of alteration in the bone cell cAMP response to PTHin vitro after chronic PTH infusionin vivo fails to support the notion that the impaired response in -D bone cells can be explained entirely by “homologous desensitization” induced by high circulating levels of PTH in the hypocalcemic, -D rat pup.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02405337
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Calcitonin and parathyroid hormone in newborn infants with fracture of the clavicle (1984)
    Springer
    Calcified tissue international 36 (1984), S. 357-360 
    Details
    ISSN: 1432-0827
    Keywords: Calcitonin ; Parathyroid hormone ; Calcium ; Newborn ; Fracture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Determinations of serum calcium (Ca), phosphorus (P), calcitonin (CT), and parathyroid hormone (PTH) were carried out in 36 full-term newborn infants with fracture of the clavicle (CF) and in 46 normal neonates (N). At the 6th hour of life the CF neonates demonstrated lower serum Ca and higher serum CT in comparison with normal infants. In the hours following, no significant differences between the two groups for the Ca levels were found, whereas serum CT remained significantly higher in the CF newborns at the 24th, 48th, and 72nd hour of life. Significant differences between normal and CF infants in the PTH serum levels were detected only at the 48th hour, when PTH was lower in the CF newborns. The results of this investigation indicate that the fracture of the clavicle is a significant and peculiar factor in stimulating CT secretion. Serum Ca level appeared to be controlled by CT rather than auto-regulating the secretion of the hormone.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02405346
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Calcium distribution in freeze-dried enamel organ tissue during normal and altered enamel mineralization (1984)
    Springer
    Calcified tissue international 36 (1984), S. 596-603 
    Details
    ISSN: 1432-0827
    Keywords: Calcium ; Ameloblasts ; X-ray microanalysis ; Transport ; Frozen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Energy dispersive X-ray microanalysis was applied to freeze-dried blocks of enamel organ tissue to determine levels of calcium in various celular regions. The tissue blocks were dissected free from adjacent forming enamel following injection of cobalt or fluoride ions, both of which temporarily inhibit enamel mineralization. In all control and experimental specimens there was an increasing gradient of calcium from the stratum intermedium cells to the distal ends of the ameloblasts. Calcium levels were significantly reduced near the distal ends of the ameloblasts following cobalt or fluoride injection as compared with controls. It is suggested that evidence of an intercellular buildup of calcium near the distal ends of the ameloblast supports a controlling function of these cells. The changes in calcium levels are correlated with alterations in mineralization known to occur in the adjacent enamel of the model systems employed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02405373
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Assessment of anin vivo diffusion chamber method as a quantitative assay for osteogenesis (1984)
    Springer
    Calcified tissue international 36 (1984), S. 77-82 
    Details
    ISSN: 1432-0827
    Keywords: Osteogenesis ; Diffusion chambers ; Alkaline phosphatase ; Calcium ; Phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The alkaline phosphatase activity and the calcium and phosphorus content of osteogenic tissue formedin vivo following the implantation of diffusion chambers loaded with rabbit bone marrow cells is reported. (In this study the term osteogenic includes osteoblastic and chondroblastic.) Chambers examined 14–70 days after implantation revealed progressive accumulation of mineral. Alkaline phosphatase activity increased until day 30 and declined thereafter. The osteogenic potential of the marrow cells decreased with increasing weight (age) of the cell donor rabbit when measured either as the percentage of chambers containing osteogenic tissue or as the amount of calcium, phosphorus, or alkaline phosphatase activity within the chambers. The results confirm that measurements of these parameters in tissue formed by cells incubated in diffusion chambersin vivo may be used as a method for assay of osteogenesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02405297
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Mineral loss in cortical and trabecular bone during high-dose prednisone treatment (1984)
    Springer
    Calcified tissue international 36 (1984), S. 269-273 
    Details
    ISSN: 1432-0827
    Keywords: Bone loss (osteopenia) ; Calcium ; Corticosteroids (glucocorticosteroids) ; Fluoride ; Vitamin D
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary To evaluate the effect of prednisone and triple treatment (sodium fluoride, calcium, and vitamin D) on trabecular and cortical bone serial bone mineral content (BMC) measurements were made at a metaphyseal (BMCD) and diaphyseal (BMCP) site on the forearm on 31 consecutive and previously bone-healthy patients scheduled for at least 24 weeks high-dose prednisone treatment. The patients were randomized into two further treatment groups: group I (n=16) received prednisone plus triple treatment and group II (n=15) received only prednisone. The two groups were similar with regard to age, sex, prednisone dose, and initial BMC. During 24 weeks treatment, BMCD (partially representing trabecular bone) and BMCP (mainly representing cortical bone) fell significantly and similarly, demonstrating that there is no preventive effect on bone mineral loss on the triple regimen. The BMC fall after 12 weeks was significantly more pronounced for metaphyseal (partially trabecular) than for diaphyseal (cortical) bone, whereas the values did not differ significantly after 24 weeks; this indicates a greater sensitivity to the hormone treatment of trabecular bone. In the entire group, the fall in BMC correlated positively with individual prednisone dose, significant at the diaphyseal site (r=0.39,P〈0.05), but not at the metaphyseal site (r=0.31, P=0.08). It is concluded that corticosteroid-induced osteopenia is a diffuse bone disease which affects trabecular as well as cortical bone, suggesting that BMC measured on the forearm reflects changes in bone mineral at other locations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02405329
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Hypervitaminosis D in the chick embryo: Comparative study on the activity of various vitamin D3 metabolites (1984)
    Springer
    Calcified tissue international 36 (1984), S. 392-400 
    Details
    ISSN: 1432-0827
    Keywords: Vitamin D ; Chick embryo ; Bone ; Calcium ; Phosphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Chick embryos were injected in the yolk sac at various ages with various doses of different vitamin D3 metabolites. Serum concentrations of total calcium and inorganic phosphate were determined 24 h after the injection and histological and electron microscopic studies of the tibiae were conducted 3–6 days after. Confirming previous results, the injection of 1,25(OH)2D3 was found to produce significant hypercalcemia and hypophosphatemia. The dose required to produce these effects decreased with age: 100 ng on the 9th day, 50 ng on the 11th, and 10 ng on the 15th. This finding is interpreted as resulting from the fact that the specialized cells in the chorionic epithelium which are considered to be involved in mineral resorption from the shell differentiate between the 11th and 13th days. Although no bone changes were observed in embryos injected before the 11th day, a rim of unmineralized trabeculae (osteoid) was observed at the periphery of the cortex of the tibial diaphysis in the embryos which had been injected after that age. Thus, in embryos injected on the 11th day with 100 ng 1,25(OH)2D3, the trabeculae formed between the 11th and 14th day remained unmineralized until the 15th or 16th day at which time they completed their mineralization. In the embryos injected on the 14th day, the alterations were more severe and could be produced with doses 10 times smaller than those required when the injections were made on the 11th day. At all ages, the doses that produced an osteoid rim also induced hypercalcemia and hypophosphatemia. The electron microscopical study of the osteoid trabeculae showed that osteoblasts and osteocytes had normal cytological characteristics and that the bone matrix did not present changes other than the reduction in mineral deposition. While the above findings do not exclude a direct action of 1,25(OH)2D3 on bone cells as the mechanism of osteoid formation, they do underline the importance of the humoral changes at least as partial determinants of this phenomenon. The activities of various vitamin D metabolites were compared using as parameter the threshold-dose required to produce a rim of unmineralized trabeculae in the tibia of 14–15 days embryos (T-D). The most active metabolite appeared to be 1,25(OH)2D3 (T-D: 10 ng); it was followed by 1,24,25(OH)3D3 (T-D: 100 ng) and 1,25,26(OH)3D3 (T-D: 100 ng). Vitamin D3 itself (T-D: 100 µg), 25(OH)D3 (T-D: 2.5µg) and 24,25(OH)2D3 (T-D: 5 µg) produced similar responses but only when administered in much larger doses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02405351
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    In vitro precocious accumulation of calcium and matrix vesicles formation in young cartilage cells: Specific effects of corticosteroids (1984)
    Springer
    Calcified tissue international 36 (1984), S. 702-710 
    Details
    ISSN: 1432-0827
    Keywords: Corticosteroids ; Cartilage ; Organ culture ; Calcium ; Matrix vesicles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The present study examined the effects of various corticosteroid and noncorticosteroid hormones upon the ultrastructure of chondroprogenitor cells and chondroblasts in an organ-culture system of late fetal condylar cartilage. Corticosteroids, (triamcinolone acetonide, dexamethasone, corticosterone) at concentrations of 10−6–10−8M stimulated markedly a precocious formation of matrix vesicles by chondroblasts. This stimulation was accompanied by a significant accretion of calcium complexes intra- and extracellularly in both the chondroprogenitor cell population and chondroblastsin vitro, as well as in the newly induced matrix vesicles. Nonglucocorticoid steroids (progesterone, estradiol, testosterone, cortexolone) did not evoke similar effects. Progesterone and testosterone, however, seemed to adversely affect the ultrastructure of the cartilage cells, whereas estradiol appeared to have a favorable effect on the morphology of cultured condylar cartilage.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02405393
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 11
    Electronic Resource
    Electronic Resource
    Site of action of the natural algicide, cyanobacterin, in the blue-green alga, Synechococcus sp. (1984)
    Springer
    Archives of microbiology 138 (1984), S. 273-277 
    Details
    ISSN: 1432-072X
    Keywords: Cyanobacteria ; Secondary metabolite ; Allelopathy ; Photosynthesis ; Electron transport ; Thylakoids ; Herbicides ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Cyanobacterin is a secondary metabolite produced by the cyanobacterium, Scytonema hofmanni. Highly purified cyanobacterin was found to inhibit the growth of many cyanobacteria at a minimum effective dose of 2 μg/ml (4.6 μM). The antibiotic had no effect on eubacteria including the photosynthetic Rhodospirillum rubrum. The site of action of cyanobacterin was further investigated in the unicellular cyanobacterium, Synechococcus sp. Electron micrographs of antibiotic-treated Synechococcus cells indicated that cyanobacterin affects thylakoid membrane structure. The antibiotic also inhibited light-dependent oxygen evolution in Synechococcus cells and in spheroplasts. These data support our conclusion that cyanobacterin specifically inhibits photosynthetic electron transport. This activity is similar to herbicides such as 3-(3,4-dichlorophenyl)-1,1-dimethyl urea (DCMU). The anhydro analog of cyanobacterin had no biological activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00402134
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 12
    Electronic Resource
    Electronic Resource
    The role of calcium in stalk development and in phosphate acquisition in Caulobacter crescentus (1984)
    Springer
    Archives of microbiology 138 (1984), S. 140-152 
    Details
    ISSN: 1432-072X
    Keywords: Caulobacter ; Prostheca development ; Stalk function ; Calcium ; Phosphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Calcium was found to stimulate stalk development in Caulobacter crescentus and to relieve the inhibition of development long known to be caused by phosphate. This suggested that phosphate inhibition could be attributed to its interaction with Ca2+, thereby depriving the cells of a factor that promoted development. Calcium was also found to promote phosphate acquisition by the cells, observed as acceleration of growth at extremes of phosphate concentration, as promotion of carbon-source utilization rather than storage, and as support for phosphate-dependent resistance to arsenate inhibition of growth. Cytological studies of dividing cells revealed that stalked siblings had greater access to exogenous phosphate for use in growth or for storage as polyphosphate, and that access of non-stalked sibling to phosphate was dependent on the length of the stalk of the dividing cell. It was concluded that the physiologic role of the stalk is enhancement of phosphate acquisition. The stimulatory role of calcium in this process was attributed to its support of stalk development and to its stabilization of internal membrane/cell envelope association within the cell-stalk juncture.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00413014
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 13
    Electronic Resource
    Electronic Resource
    Structural analysis of EcoRI-DNA complexes as revealed by electron microscopy (1984)
    Springer
    Archives of microbiology 140 (1984), S. 265-270 
    Details
    ISSN: 1432-072X
    Keywords: EcoRI ; EcoRI-DNA complexes ; EcoRI* activity ; Recognition sites ; Frequency of binding ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Electron microscopy of negatively stained isolated restriction enzyme EcoRI revealed particle projections with triangular or square outlines, indicating that the enzyme, in its tetrameric state, is tetrahedron-like. The two dimers making up the tetramer appear to be arranged in two planes orthogonal to each other. Complexes formed by EcoRI with the plasmids pBR322 or pGW10 were investigated by electron microscopic spreading techniques. In the presence of Mg2+, EcoRI was bound to the DNA molecules to form pearl necklace-like aggregates. The number of bound EcoRI particles was much higher as the sum of EcoRI-and 5′..AATT..3′ sites (with exceptions, the 5′..AATT..3′ sites may function as one type of EcoRI* sites) along the DNAs, indicating unspecific binding. In the absence of Mg2+, EcoRI was bound to the DNA only at the recognition site for EcoRI and the sites where the tetranucleotide sequence 5′..AATT..3′ was present. A direct correlation of the local concentrations of the bases A and T within the flanking sequences of the binding sites with the frequency of EcoRI to the DNA was observed. Dimers and tetramers of the enzyme was found to bind to the DNA. Tetramers occasionally exhibited two binding sites for DNA as indicated by the observation of DNA loops originating at the sites of bound tetrameric EcoRI particles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00454940
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 14
    Electronic Resource
    Electronic Resource
    Elemental analysis of particles in fungal zoospores (1984)
    Springer
    Archives of microbiology 139 (1984), S. 102-104 
    Details
    ISSN: 1432-072X
    Keywords: Fungus ; Zoospore ; Blastocladiella ; Allomyces ; Gamma ; Particle ; Phosphate ; Calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The elemental composition of gamma particles in zoospores ofAllomyces macrogynus andBlastocladiella emersonii was determined by use of energy dispersive X-ray analysis of glutaraldehyde fixed, thin section zoospores. Isolated preparations of gamma particles were also examined. Gamma particles contained no detectable elements. Similar sized, globular, electron dense cytoplasmic inclusions contained phosphorus and calcium. We suggest that previous studies assigning calcium and phosphorus to gamma particles may have been based on confusion of these two types of cytoplasmic inclusions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00692722
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 15
    Electronic Resource
    Electronic Resource
    The role of calcium ions in phytochrome-mediated germination of spores of Onoclea sensibilis L. (1984)
    Springer
    Planta 160 (1984), S. 12-20 
    Details
    ISSN: 1432-2048
    Keywords: Calcium ; Calmodulin ; Germination (spore) ; Onoclea ; Phytochrome and Ca2+ ; Pteridophyta
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Phytochrome is confirmed to be the photoreceptor pigment in the germination response of Onoclea sensibilis L. by demonstrating red-far-red (R-FR) photoreversibility. External Ca2+ is required for this response with a threshold at a submicromolar concentration. Ethylene glycol-bis(β-amino-ethyl ether)-N,N,N′,N′-tetraacetic acid, La3+ and Co2+ reversibly inhibit germination. Lanthanum only inhibits germination when applied before or during irradiation, indicating that the external Ca2+ requirement is transient, although in the absence of Ca2+ the R-stimulated system remains maximally poised to accept the ion for over 4 h after irradiation. The ability to respond to Ca2+ 4.1 h after R-irradiation is not reversed by FR-irradiation, indicating that Ca2+ transport has been uncoupled from phytochrome. Barium and Sr2+, but not Mg2+ can substitute for Ca2+. Artificially increasing the concentration of intracellular free Ca2+ with the ionophore A 23187 stimulates germination in the dark. The Ca2+-calmodulin antagonists, trifluoperizine and chlorpromazine, reversibly inhibit germination. Calcium is required in phytochrome-mediated fern spore germination; it may be acting as a second messenger.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00392460
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 16
    Electronic Resource
    Electronic Resource
    Cytological effects of ionophore-induced stimulation on the exocrine pancreas of the rat (1984)
    Springer
    Cell & tissue research 235 (1984), S. 699-701 
    Details
    ISSN: 1432-0878
    Keywords: Ionophore A-23187 ; Calcium ; Exocrine pancreas ; Secretion ; Zymogen granule
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Rat-pancreas lobules were incubated with the ionophore A-23187 in the presence of Ca2+. After 90 min, some of the acini were partially or almost completely depleted of their zymogen granules while others had the appearance of resting acini. With few exceptions, the cells of a given acinus were degranulated to a comparable level. Slight dispersion of the zymogen granules was noticed in cells incubated in a Ca2+-free medium containing EGTA with or without A-23187. In the presence of Ca2+ the secretory response obtained with the ionophore was comparable to that observed with 10-5M urecholine. The results obtained provide cytological evidence that the secretory response is only partially determined at the membrane-receptor level and that other mechanisms intervene between cytosol Ca2+ increase and exocytosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00226972
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 17
    Electronic Resource
    Electronic Resource
    Ultrastructural changes in the spermatogonia and spermatocytes of Poecilia reticulata during spermatogenesis (1984)
    Springer
    Cell & tissue research 237 (1984), S. 219-226 
    Details
    ISSN: 1432-0878
    Keywords: Spermatogonia ; Spermatocytes ; Carbohydrates ; Guppy ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The structure of guppy (Poecilia reticulata) spermatogonia and spermatocytes has been studied using electron microscopy. The spermatogonia, situated at the apex of the seminiferous tubule, are almost all surrounded by a network of Sertoli cells; they have very diffuse chromatin and one or two large nucleoli. The cytoplasm contains relatively few organelles, although annulate lamellae are found. The mitochondria have few cristae and are concentrated at one pole of the cell; they are sometimes found with intermitochondrial cement. These spermatogonia are separated from each other, having no intercellular bridges or inclusion in Sertoli cells, and are relatively undifferentiated; they correspond to stem cells. The spermatogonia beneath the apex are organized into cysts. First-generation spermatogonia are more dense and heterogeneous, their nuclei becoming smaller and their chromatin becoming denser during successive generations. In spermatocytes, the synaptinemal complex exists as a modified form until metaphase. The concentration of organelles in the cytoplasm increases and the organelles become more diversified as spermatogenesis progresses. Many cytoplasmic bridges are observed (several per cell), indicating that the cells remain in contact after several divisions. These changes in germ cell structure have been related to some of the characteristic features of spermatogenesis in guppy, e.g. the large number of spermatogonial generations and the complexity of spermiogenesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00217139
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 18
    Electronic Resource
    Electronic Resource
    Marginal plates in hepatic peroxisomes of Ichthyophis glutinosus (Amphibia: Gymnophiona) (1984)
    Springer
    Cell & tissue research 238 (1984), S. 413-416 
    Details
    ISSN: 1432-0878
    Keywords: Peroxisomes ; DAB-cytochemistry ; Electron microscopy ; Liver, amphibian ; Gymnophiona ; Ichthyophis glutinosus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of hepatic peroxisomes was investigated in Ichthyophis glutinosus (Amphibia: Gymnophiona), employing perfusion fixation and the diaminobenzidine (DAB) technique for the visualization of catalase. The majority of peroxisomes is circular or rod-shaped, although elongated particles occasionally occur. They contain a finely granular matrix, lightly stained after the DAB procedure. Their mean diameter is approximately 0.25 μm. Serial sections reveal that the circular and rod-shaped peroxisomal profiles are cross and oblique sections of highly tortuous, tubular organelles exceeding 2 μm in length. In addition to tubular profiles, elongated, rectangular particles, as well as straight dumbbell-shaped organelles with distinct marginal plates are observed. They range from 900 to 1650 nm in length (mean = 1200 nm). In the flattened, thin central portion of the dumbbell-shaped particle, the peroxisomal membranes form a cisterna enclosing one or two uniformly thick marginal plates, which display a definite substructure with a periodicity of 10 nm. These findings indicate that peroxisomes in the liver of Ichthyophis exhibit a complex organization. It is suggested that the organelles undergo a specific differentiation process, morphologically characterized by the formation of enlarged segments of unusual shape.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00217316
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 19
    Electronic Resource
    Electronic Resource
    Studies on the morphology of the isolated perfused rabbit ovary (1984)
    Springer
    Cell & tissue research 235 (1984), S. 59-63 
    Details
    ISSN: 1432-0878
    Keywords: Ovulation (rabbit) ; Graafian follicle ; Perfusion ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Isolated ovaries from untreated, sexually mature rabbits were introduced into an in vitro perfusion system and perfused with a chemically defined medium containing albumin. The ovaries were perfused for up to 15 h (mean 11.5 h) and then processed for morphological investigation. Both at the light- and electron-microscopical levels, most of the ovaries exhibited a normal structure comparable with ovaries in situ. In two cases, however, marked accumulations of bacteria were found, although not inside the follicles. Since ovulation in the rabbit normally occurs between 9.5–13 h after mating or human chorionic gonadotrophin treatment, this model seems adequate for studies of ovulation in vitro. It is, however, important to study the ovaries microscopically after the perfusion to detect artifacts, e.g., bacterial infection, that may have influence on the process of ovulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00213723
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 20
    Electronic Resource
    Electronic Resource
    Regions of putative acetylcholine receptors at synaptic contacts between neurons maintained in culture and subsequently fixed in solutions containing tannic acid (1984)
    Springer
    Cell & tissue research 235 (1984), S. 85-89 
    Details
    ISSN: 1432-0878
    Keywords: Tannic acid ; Acetylcholine receptors ; Tissue culture ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Spinal cord neurons from 9-day chick embryos were maintained in culture for up to 35 days and then fixed in 4% cacodylate-buffered glutaraldehyde containing 2% tannic acid. After about 15 days in culture a small percentage of the synaptic specializations present were characterized by striking electron-dense striations averaging 15 nm in width, oriented perpendicular to the postsynaptic membrane. These structures increased in frequency with time in culture (to a maximum of about 10% of all synapses in the oldest cultures); they were asymmetrical, protruding approximately 8 nm into the synaptic cleft, and more deeply (approximately 15–18 nm), into the postsynaptic cytoplasm. On the basis of earlier work by Sealock (1980) they are interpreted as concentrations of acetylcholine receptors. Similar membrane differentiations were also seen associated with active-zone areas of a few presynaptic membranes, and the possibility that these represent presynaptic acetylcholine receptors is discussed. Additional observations reported are (1) the presence of striations resembling those seen at the postsynaptic membrane in the membranes of some postsynaptic vesicles, and (2) filamentous links between the striations and cytoskeletal elements of the postsynaptic cell.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00213727
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 21
    Electronic Resource
    Electronic Resource
    Fine structure of monoamine-containing basal cells in the taste buds on the barbels of three species of teleosts (1984)
    Springer
    Cell & tissue research 235 (1984), S. 479-484 
    Details
    ISSN: 1432-0878
    Keywords: Monoamine-containing cells ; Taste bud ; Paracrine cells ; Mechanoreceptors ; Electron microscopy ; Teleosts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The taste buds on the barbels in three species of teleosts (Cyprinus carpio, Misgurnus anguillicaudatus, Parasilurus asotus) were studied by means of fluorescence and electron microscopy. Intensely yellow-fluorescent cells, which are disk-shaped and located exclusively in a basal position, are observed in the barbel-buds of all fishes examined. The basal cells contain a large number of small clear vesicles approximately 40–60 nm in diameter, which show a tendency to aggregate in the cytoplasm facing the junction of the nerve terminals; chemically transmitting synapses are seen in the latter region. It is suggested from the present observations that the basal cells in the barbel-bud may originate from Schwann cells and have a dual function both as mechanoreceptors and paracrine elements. Since the administration of 5,6-DHT results in an appearance of small dense vesicles among the small clear vesicles, the possibility exists that the basal cell may be capable of taking up monoamines and storing them in the small clear vesicles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00226942
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 22
    Electronic Resource
    Electronic Resource
    Electron-microscopic demonstration of the distribution of calcium deposits in the exocrine pancreas of the rat after application of carbachol, atropine, cholecystokinin, and procaine (1984)
    Springer
    Cell & tissue research 235 (1984), S. 683-690 
    Details
    ISSN: 1432-0878
    Keywords: Exocrine pancreas ; Calcium pool ; Calcium release ; Electron microscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In an attempt to identify a cellular Ca2+-pool, from which calcium is released when secretagogues are applied, tissue fragments of the rat exocrine pancreas were incubated and fixed with glutaraldehyde in the presence of calcium. By means of this procedure electron-dense deposits were found on plasma membranes. X-ray microanalysis showed that these deposits contain calcium. Stimulation of tissue fragments with the use of the secretagogues carbachol or cholecystokinin reduced the number of deposits by about 80%. When the antagonist atropine was applied after carbachol stimulation, deposits reappeared on cell membranes, which then disappeared again after a second stimulation with cholecystokinin. In the presence of procaine, carbachol was inhibited and only slightly reduced the Ca2+-deposits on the plasma membranes. These results suggest that a calcium pool, from which calcium is released to induce enzyme secretion on stimulation, is located in the cell membrane
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00226969
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 23
    Electronic Resource
    Electronic Resource
    Morphological and morphometrical changes in chloride cells of the gills of Pimephales promelas after chronic exposure to acid water (1984)
    Springer
    Cell & tissue research 236 (1984), S. 121-128 
    Details
    ISSN: 1432-0878
    Keywords: Chloride cells ; Acid stress ; Gill ; Electron microscopy ; Fathead minnow
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Fathead minnows, Pimephales promelas, were exposed for 129 days to Lake Superior water acidified with sulfuric acid by means of a flow-through toxicant injection system. The effects of chronic acid stress (pH 6.5, 6.0, 5.5, 5.0) on gill histology were examined. Most of the histological effects were seen at pH 5.5 and 5.0 and were confined primarily to changes in numbers, distribution, and morphology of chloride cells. At low pH levels there tend to be more chloride cells in the gill epithelium and an increased percentage of these cells in the secondary lamellae. In contrast to normal chloride cells, chloride cells from fish exposed to low pH frequently had apical pits while some had bulbous apical evaginations. The occurrence of structural changes in chloride cells during exposure to acid water suggests that chloride cells may be involved in acclimation to acid stress.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00216521
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 24
    Electronic Resource
    Electronic Resource
    Morphometric evaluation of lipid droplet associations with secretory vesicles, mitochondria and other components in the lactating cell (1984)
    Springer
    Cell & tissue research 236 (1984), S. 471-475 
    Details
    ISSN: 1432-0878
    Keywords: Lactating cell ; Lipid droplets ; Secretory vesicles ; Mitochondria ; Intracellular associations ; Electron microscopy ; Milk secretion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The size, cellular location, and identity of surface-associated components were determined for lipid droplets in lactating cells. Transmission electron-microscopic measurements were made involving 3801 droplets in approximately 211 cells from three rats and 1197 droplets in 66 cells from a mouse. For the purposes of droplet evaluation, cells were divided into seven locations ranging from basal to secreting positions. Droplets were also categorized with respect to contact with other droplets, basolateral plasma membrane, mitochondria, Golgi apparatus, secretory vesicles, and endoplasmic reticulum-cytoplasm (ERC). Data on droplet size showed that droplet growth occurs mainly in the secretory position, confirming previously published findings. Lipid droplets from mouse tissue, although somewhat smaller in size showed similar growth trends to those of the rat. Data on numbers of droplet contacts and percentages of droplet circumferences involved in associations with other cell components showed that the dominant interaction of lipid droplets was with the ERC. However, intimate association of droplets with mitochondria was noted in all cellular locations. In addition, nursed animals exhibited a greater proportion of droplet surface association with secretory vesicles and less in contact with mitochondria in comparison to those not nursed. The significance of these relationships to milk synthesis and secretion is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00214252
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 25
    Electronic Resource
    Electronic Resource
    Endoplasmic reticulum whorls as a source of membranes for early cytaster formation in parthenogenetically stimulated sea urchin eggs (1984)
    Springer
    Cell & tissue research 236 (1984), S. 237-244 
    Details
    ISSN: 1432-0878
    Keywords: Aster formation ; Calcium ; Endoplasmic reticulum ; Hypertonic stress ; Parthenogenetic stimulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Sea urchin eggs exposed to a continuous hypertonic treatment rapidly form many concentric whorls of endoplasmic reticulum (ER) during the pre-activation period of the parthenogenetic development. These whorls, however, are only a temporary configurational alteration of ER which begin to break up just prior to egg activation. The conversion back to normal vesicles and lamellae occurs not only concurrently with the appearance of early cytastral areas, but also frequently in close association with the formation of these membranous areas. It is revealed here that membrane elements from disrupting whorls may become incorporated into adjacent, developing clear areas, early cytastral areas, and that this ER constitutes an initial major source of membranes for these early astral areas. Having previously suggested that the actual formation of ER whorls occurs in direct response to released intracellular calcium in hypertonic stressed eggs, the new findings, along with other related data and correlations, further suggest that whorl disruption and the formation of associated astral areas can be correlated with a corresponding decrease in the concentration of this released calcium in the cytoplasm.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00216536
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 26
    Electronic Resource
    Electronic Resource
    Electron-microscopic study of silver staining of nucleoli in growing oocytes of rat ovaries (1984)
    Springer
    Cell & tissue research 236 (1984), S. 249-255 
    Details
    ISSN: 1432-0878
    Keywords: Oocyte ; Nucleolus ; Silver staining ; Electron microscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The nucleoli of dictyate-stage growing oocytes in rat ovaries were examined both with routine electron microscopy and electron microscopy after silver nitrate and ammoniacal silver nitrate (Ag-AS) staining. The nucleoli of the unilaminar follicular oocytes consist of twisted strands of dense fibrillar components, aggregates of granular components, and small fibrillar centers. After Ag-AS staining, silver grains are numerous on the dense fibrillar strands, fewer on the fibrillar centers, and very sporadic on the granular aggregates. The same stainability of three nucleolar components with the Ag-AS method was also confirmed in the nucleoli segregated by actinomycin D. During the transition of growing oocytes from bilaminar to plurilaminar follicle stage, the nucleolar dense fibrillar strands gradually conglomerate and are transformed into large and compact spherules. The stainability of dense fibrillar components with the Ag-AS method was lost along with this nucleolar transformation. These results may provide some new clues on the functional significance of AgAS-positive proteins in the nucleoli.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00214225
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 27
    Electronic Resource
    Electronic Resource
    Structure of the parathyroid glands, as revealed by different methods of fixation (1984)
    Springer
    Cell & tissue research 235 (1984), S. 51-58 
    Details
    ISSN: 1432-0878
    Keywords: Parathyroid glands ; Electron microscopy ; Light microscopy ; Quantitative histology ; Mongolian gerbil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Stereology and semi-automatic image analysis were used with the aim of comparing the structure of parathyroid glands from untreated adult Mongolian gerbils fixed by immersion with those fixed by perfusion. Subclassification of the chief cells based upon the staining affinity or electron density of the cytoplasm was readily performed only in glands fixed by immersion, and so-called atrophic cells were observed only in these glands. The atrophic cells were often surrounded by “light” chief cells. In glands fixed by perfusion, “light” chief cells were only rarely encountered. A significant difference between glands fixed by immersion and those fixed by perfusion was found only with regard to the form of cells and nuclei, those fixed by perfusion being more spherical. When comparing individual cells within glands fixed by immersion, “light” chief cells were more spherical and had a significantly larger nuclear and cellular size, and a lower mitochondrial volume density than the “intermediate”/“dark” chief cells. Otherwise there were no significant differences in any of the parameters investigated. These data indicate that occurrence of socalled “light” chief cells and atrophic cells is a result of improper fixation. The results of this study do not favour the concept of a functional cycle with a simultaneous occurrence of active and inactive cells within parathyroid glands.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00213722
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 28
    Electronic Resource
    Electronic Resource
    Interdigitating cells in the lymphoid tissues of bovine fetuses and calves (1984)
    Springer
    Cell & tissue research 235 (1984), S. 153-158 
    Details
    ISSN: 1432-0878
    Keywords: Bovine ; Interdigitating cell ; Lymphoid tissues ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Electron-microscopic studies of lymphoid tissues from bovine fetuses and from calves disclosed a non-lymphoid cell type in the thymus-dependent zones of secondary lymphoid tissues and in the thymus that is distinguishable from reticulum cells, epithelial and endothelial cells, and macrophages. Based on morphological and topographical criteria, the cell is identified as the interdigitating cell. In addition, studies of the tissues of normal and virus-challenged fetuses, and of conventionally reared calves, indicated that the interdigitating cells originate from monocytoid cells, which undergo differentiation in the thymus-dependent zones during an immune response.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00213735
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 29
    Electronic Resource
    Electronic Resource
    The fine structure of identified electrotonic synapses following increased coupling resistance (1984)
    Springer
    Cell & tissue research 235 (1984), S. 243-249 
    Details
    ISSN: 1432-0878
    Keywords: Gap junction ; Electron microscopy ; Freeze fracture ; Cell-to-cell communication
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Gap junctions exist in the septa between the segments of the lateral giant axons in the ventral nerve cord of the crayfish Procambarus. A large increase in the resistance (uncoupling) of these gap junctions was brought about by mechanical injury to the axonal segments. Both thin sections and freeze-fracture preparations were used to monitor the morphological changes which occurred up to 45 min after injury. There was no apparent change in the organization (a loose polygonal array) of the intramembrane particles which make up the junctional complex up to 45 min after injury. In some instances, however, the intramembrane particles appeared to have moved away from the junctional area. Other junctional regions were internalized and appeared similar to what have been called annular gap junctions. Also at this time (20–25 min after injury), a dense cytoplasmic plug formed in uninjured axon near the junctional region. It is concluded that the gap junctions that exhibit a loose polygonal organization of the intramembrane particles may be either in a state of low resistance (coupled) or a state of high resistance (uncoupled).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00217847
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 30
    Electronic Resource
    Electronic Resource
    Studies on the morphology of the isolated perfused rabbit ovary (1984)
    Springer
    Cell & tissue research 235 (1984), S. 565-573 
    Details
    ISSN: 1432-0878
    Keywords: Ovulation ; Perfusion ; Graafian follicle (rabbit) ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ovulation was induced in rabbits by intravenous administration of human chorionic gonadotrophin (HCG), and 4–5 h later the ovaries were isolated and introduced into an in-vitro perfusion system containing synthetic medium with albumin. Rupture of follicles occurred in vitro within the physiological time range (mean 11.3 h after injection of HCG), although with a reduced frequency. Preovulatory and ruptured follicles were studied in detail by light and electron microscopy. In the granulosa layer of ruptured or preovulatory follicles cytoplasmic blebbing activity, disappearance of CallExner bodies and differentiation toward luteinized cells were found. Perhaps the most important sign of normal preovulatory development in vitro was that the basement membrane surrounding the granulosa layer was penetrated by projections of granulosa cells. In the absence of this penetration phenomenon the granulosa layer prolapsed out of the follicle. Immediately before rupture, follicles showed marked degeneration, restricted to the outer layers of the apical wall, which is compatible with the hypothesis that degradative enzymes are released close to the surface of preovulatory follicles. Although the majority of follicles that ovulated under in-vitro conditions showed the same kind of morphological alterations as can be seen in vivo, occasional atypical ruptures occurred without any overt signs during perfusion. Also technical manipulations of the perfusion system, e.g., nonphysiological increase of perfusion pressure, could force follicles to rupture. This illustrates the importance of careful morphological study of all ovaries perfused in vitro before conclusions are drawn.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00226954
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 31
    Electronic Resource
    Electronic Resource
    Electron-microscopic investigation of the innervation of the pars distalis of the hypophysis in adult Rana temporaria L. (1984)
    Springer
    Cell & tissue research 237 (1984), S. 149-154 
    Details
    ISSN: 1432-0878
    Keywords: Pituitary gland, pars distalis ; Innervation ; Synaptoid contacts ; Electron microscopy ; Rana temporaria L
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the pars distalis of the hypophysis of adult Rana temporaria, three types of nerve-fiber profiles were found at two distinct sites, in both lateral parts of the bordering regions of the anterior lobe with the intermediate lobe of the hypophysis. The first type of nerve-fiber profile consists of bundles of very fine axonal elements (diameter: 〈0.7 μm). The second type is formed by larger nerve fibers (diameter up to 4 μm) containing a few neurosecretory granules of approximately 100 nm. The third type of nervefiber profile resembles the second type but these nerve fibers make synaptoid contacts on at least two different types of glandular cells. The possible functional significance of these nerve fibers in the pars distalis is discussed. No nerve fibers were found (1) in the central part of the bordering region of the pars distalis with the intermediate lobe, (2) at the bordering region with the median eminence and (3) with the neurohypophysial stalk, and (4) in all other parts of the pars distalis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00229210
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 32
    Electronic Resource
    Electronic Resource
    Vascularization and glomerular ultrastructure in the pig mesonephros (1984)
    Springer
    Cell & tissue research 238 (1984), S. 165-175 
    Details
    ISSN: 1432-0878
    Keywords: Mesonephros ; Pig embryo ; Glomerulus ; Microvasculature ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Vascularization of the pig mesonephros was investigated in embryos 5–8 cm in length. Vascular injections with microfil were cleared and dissected; corrosion casts were studied under the scanning electron microscope (SEM). Perfusion-fixed tissue was used for SEM and transmission electron microscope (TEM) studies, including freeze-fracture specimens. The branches of one mesonephric artery carry up to 15 glomeruli. Several glomeruli occupy the same arterial branch, with very short afferent arterioles proper. The efferent vessels, frequently 2–5, leave the extensive vascular pole opposite the entering arteriole and split into peritubular capillaries radiating towards the superficial veins. These capillaries form vascular regions in the shape of flattened pyramids. Along its course, one nephron is supplied by vessels derived from 4–7 glomeruli. The nephrons have less vascular contact than in the definitive kidney. The ultrastructure of the single mesonephric vessels matches the metanephric counterparts. Epithelioid cells with renin granules are common in afferent arterioles, larger arteries, and efferent vessels. The lobulated glomeruli are up to 750 μm long and flattened, showing the usual features of podocytes, mesangial cells, and an attenuated endothelium with fenestrations between 50 and 250 μm. It partially retains its own basement membrane. There is no proximal mesangium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00215158
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 33
    Electronic Resource
    Electronic Resource
    The effect of long-term denervation on the ultrastructure of Pacinian corpuscles in the cat (1984)
    Springer
    Cell & tissue research 238 (1984), S. 387-394 
    Details
    ISSN: 1432-0878
    Keywords: Pacinian corpuscles, cat ; Denervation ; Atrophy ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of Pacinian corpuscles of the cat located in the crural region and innervated by the interosseous nerve was studied 1 to 14 months after denervation. Both the Pacinian inner core and capsule remained well preserved one month after denervation. However, the denervated inner cores underwent progressive atrophy and wasting, which resulted in a gradual reduction of the amount of inner-core cells and lamellae, widening of interlamellar clefts, formation of empty spaces in the axial region and a considerable increase in the number of collagen fibrils. In spite of the wasting, the inner core still survived 14 months after denervation, but at least half of its volume became occupied by collagen fibrils which surrounded the remaining inner-core cells and lamellae. Collagen fibrils assembled in the denervated core were markedly thinner than those found in the capsule, as is also the case in normal Pacinian corpuscles. In the capsule, discrete focal degeneration, occasional pyknosis of the innermost capsular cells and macrophage infiltration were observed from the first month after nerve section onward, but the number of capsular layers remained within the normal range (30–40) up to 14 months after denervation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00217312
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 34
    Electronic Resource
    Electronic Resource
    Enhanced cellular membrane contrast in a marine alga by Osmium-azole complexes (1984)
    Springer
    Protoplasma 119 (1984), S. 48-54 
    Details
    ISSN: 1615-6102
    Keywords: Electron microscopy ; Marine alga ; Membrane contrast ; Osmium-azole complexes ; X-ray microanalysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Addition of certain heterocyclic nitrogen-carbon compounds to standard osmium tetroxide solutions used as secondary fixative resulted in an enhanced general membrane contrast in cells of the marine algaEmiliania huxleyi (Lohmann) Kamptner. Ultrastructural cell morphology and the contrast distribution were compared between cells treated according to a standard secondary fixation procedure and cells post-fixed when above mentioned heterocyclic compounds were introduced; in both cases some of the ultrathin sections were post-stained. Different compounds were tested: 1,2,4-triazole (TRA), 3-amino-1,2,4-triazole (A-TRA), 5-amino-tetrazole (A-TEA) and 2,4,6-tri-amino-1,3,5-triazine (melamine). The results were interpreted to indicate the possible bonding types arising from interaction of the heterocyclic compounds with osmium tetroxide and with membrane constituents. Interpretations were partly inspired by considerations from coordination chemistry. All above tests which did not include post-staining of thin sections could be performed at alkaline pH, and consequently calcified structures were preserved. The enhanced osmium accumulation at membranes was verified with X-ray microanalysis, which also showed that in the cases where membranes were visibly contrasted, localization of probable sites of intracellular non-crystalline calcium was facilitated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01287816
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 35
    Electronic Resource
    Electronic Resource
    Calcium-induced fusion of fusogenic wild carrot protoplasts (1984)
    Springer
    Protoplasma 120 (1984), S. 209-215 
    Details
    ISSN: 1615-6102
    Keywords: Fusion ; Calcium ; Protoplast ; Membrane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Rather than selecting for a chemical fusogen one can select for a fusogenic plant membrane (i.e., one that will fuse readily). Wild carrot suspension culture cells can be grown under conditions which cause the released protoplasts to have a high potential to fuse. Protoplast fusion is enhanced by calcium and inhibited by EGTA. When 10mM calcium (pH6.0) is added, fusion percentages of 60% are common. The mild fusion treatment appears to have no effect on callus regeneration and differentiation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01282601
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 36
    Electronic Resource
    Electronic Resource
    Response to chilling stress in plant cells II. Redistribution of intracellular calcium (1984)
    Springer
    Protoplasma 121 (1984), S. 17-24 
    Details
    ISSN: 1615-6102
    Keywords: Chilling-sensitivity ; Calcium ; Chlortetracyline ; A 23187 ; Lycopersicon ; Digitalis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have investigated the possibility that the rapid low temperature effects upon cyclosis and subcelluar structure might be due to a breakdown in compartmentation of intracellular calcium, leading to an increase in cytoplasmic Ca2+. Changes in fluorescence of chlortetracycline (CTC), a probe for membrane-bound Ca2+ were monitored in the corners of individual trichome cells (effective spot size ca. 800 square microns) with the aid of a Zeiss epifluorescence microscope linked to a Zeiss Zonax analyzing system. A consistent decrease in signal was observed as cells of chilling-sensitiveLycopersicon esculentum Mill. (cv.Ace) were cooled below their threshold temperature for chilling sensitivity. On rewarming, as the temperature rose above the chilling threshold, there was an increase in fluorescent signal. In contrast, trichomes ofDigitalis purpurea (chilling-resistant) showed no such changes. The uncoupling agent, CCCP, and the Ca2+-chelator, EGTA, induced marked decreases in the fluorescent signal in cells from both species. A more direct approach to testing the hypothesis was to examine the effect of modulating cytoplasmic Ca2+ with the aid of the Ca2+ -ionophore A 23187 and a Ca2+ concentration series in EGTA buffer. Above 10−8 M external free Ca2+, streaming began to be inhibited, full inhibition occurring at 5 x 10−6M Ca2+. The strand structure started to disappear when the Ca2+ rose above 10−7M. Disappearance of strands was accompanied by an increase in the number of cells with vesiculated cytoplasm, an effect analogous to that of chilling temperatures on these cells. The phenothiazines, trifluoperazine and chlorpromazine (10−5M) had similar effects. However but such effects were not seen with R 24571 or N(6-aminohexyl)5-chloro-1-napthalenesulfonamide (W 7) until concentrations were reached that orders of magnitude above their IC50 for calmodulin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01279748
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 37
    Electronic Resource
    Electronic Resource
    Tentacle contraction inDiscophrya collini: The effects of ionophore A23187 and ruthenium red on Ca2+-induced contraction and uptake of extracellular calcium (1984)
    Springer
    Protoplasma 122 (1984), S. 125-131 
    Details
    ISSN: 1615-6102
    Keywords: Calcium ; Contraction ; Discophrya ; Ionophore A23187 ; Ruthenium red ; Tentacles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The tentacles of the suctorian protozoonDiscophrya collini are stimulated to contract by externally applied Ca2+. The role of extracellular Ca2+ in tentacle contraction was studied by monitoring45Ca2+ uptake, using ionophore A23187 to facilitate membrane transport of calcium and ruthenium red (RR) as an inhibitor of transport. The degree of tentacle retraction was dependent upon external Ca2+ concentration and studies with45Ca2+ using scintillation counting indicated a linear relationship between external Ca2+ concentration and Ca2+ uptake. Uptake of Ca2+ was enhanced in the presence of the ionophore while RR caused little inhibition.45Ca2+ uptake was only partially inhibited by RR when cells were subjected to a Ca2+, ionophore and RR mixture. Grain counts from light microscope autoradiographs after treatment of cells with45Ca2+/ionophore,45Ca2+/RR or45Ca2+ alone showed heavy, light and intermediate labelling respectively. In all instances the grains were evenly distributed within the cell. These observations are interpreted as supporting the suggestion that the ionophore enhances both the uptake of extracellular Ca2+ and release of Ca2+from an internal source, while the RR could only partially prevent movement of Ca2+ through the plasma mebrane. A model is presented suggesting that tentacle retraction is mediated by cytosolic Ca2+ levels which are determined by the fluxing of Ca2+ across the plasma membrane and the membrane of elongate dense bodies which act as internal Ca2+ reservoirs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01279445
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 38
    Electronic Resource
    Electronic Resource
    Biological and biochemical analysis of soils (1984)
    Springer
    Plant and soil 76 (1984), S. 127-137 
    Details
    ISSN: 1573-5036
    Keywords: Adenylate pool ; Biomass volume ; CO2 evolution ; Chitin ; DNA ; Electron microscopy ; Enzymes ; Fluorescent antibody ; Fumigation-respiration ; Fungi Histochemistry ; Imunofluorecence ; Jones-Mollison technique ; Microcosms ; Monoclonal antibodies ; Nitrogen ; Nutrients ; Oxygen consumption ; Phosphorus ; Phytotoxins ; Plate counts ; Rhizobium ; Rhizosphere ; Sulphur ; Xenobiotics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary There is an immense literature on biological and biochemical analyses of soils. Such analyses have revealed the enormous richness of species in soil and their vast range of metabolic potentials and ecological diversity. Accordingly, the approaches used to investigate the soil biota and its biochemistry usually have to be modified or adapted depending upon the purpose of the investigation. Studies of micro-organisms in the soil environment, are complicated because microbial cells are commonly attached to surfaces where they live side-by-side with other populations in consortia usually containing different morphological and physiological types. Such assemblages of organisms cannot be described quantitatively using cultural techniques, such as plate counts, which underestimate both cell numbers and viable biomass. The development of more powerful observational and staining techniques has improved our knowledge of the diverse morphological and biochemical composition of soil micro-communities. Such findings have been amplified at a grosser level by laboratory studies with multi-component systems (microcosms) to mimic field situations and to assess the range of biochemical potentials of microbial consortia. But despite notable advances in analytical methods we are still, with a few exceptions, unable to detect or identify those microorganisms which carry out specific biochemical transformations or determine whether particular cells are alive, dormant or dead at the time of observation. Considerable work has been done to define some of the fundamental ecological attributes of microbial assemblages in soil. Productive work on the metabolic activities of the soil microbiota, specially geochemical transformations of C, N, S and P, has been under way for more than a century. But only in more recent years have more sensitive and reproducible analytical methods become available to measure viable biomass in soil. This will enable some insight to be gained into the role that microbial biomass plays as a labile source and sink for plant nutrients.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02205573
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 39
    Electronic Resource
    Electronic Resource
    Soil organic matter and structural stability: mechanisms and implications for management (1984)
    Springer
    Plant and soil 76 (1984), S. 319-337 
    Details
    ISSN: 1573-5036
    Keywords: Aggregates ; Aluminium ; Bacterial mucilage ; Binding agents ; Calcium ; Cation bridges ; Complexing agents ; Dispersion ; Electron microscopy ; Electrophoretic mobility ; Fungal hyphae ; Glues Iron ; Management Periodate ; Polysaccharides ; Rhizosphere ; Roots ; Slaking
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The stability of pores and particles is essential for optimum growth of plants. Two categories of aggregates macro- (〉 250 μm) and micro- (〈250 μm) depend on organic matter for stability against disruptive forces caused by rapid wetting. Dispersion of clay particles from microaggregates is promoted by adsorption of complexing organic acids which increase the negative charge on clays. The acids are produced by plants, bacteria and fungi. However, the dispersibility of clay in microaggregates is offset by the binding action of polysaccharides, mainly mucilages produced by bacteria, but also by plant roots and fungal hyphae. The stability of microaggregates is also enhanced by multivalent cations which act as bridges between organic colloids and clays. Macroaggregates are enmeshed by plant roots, both living and decomposing, and are thus sensitive to management, and increase in number when grasses are grown and the soil is not disturbed. Lack of root growth,i.e. fallow, has the opposite effect. Various implications for management of soil structure are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02205590
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 40
    Electronic Resource
    Electronic Resource
    Soil acidity factors and nodulation ofTrifolium repens (1984)
    Springer
    Plant and soil 78 (1984), S. 367-379 
    Details
    ISSN: 1573-5036
    Keywords: Acidity ; Aluminium ; Calcium ; Manganese ; Nodulation ; pH Rhizobium ; Rhizosphere ; Root elongation ; Root hairs ; Trifolium repens ; White clover
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Effects of factors associated with soil acidity (low pH, low calcium, high aluminium and high manganese) on theTrifolium repens-Rhizobium trifolii symbiosis were investigted under laboratory conditions using an axenic solution-culture technique. 200 μM manganese increased root elongation in the range pH 4.3–5.5, but had no effect on root hair formation, the number of Rhizobium in the rhizosphere, or nodule formation. Root elongation and root hair formation were unaffected at pH 4.3 when 500 or 1000μM calcium was supplied, whereas multiplication of Rhizobium in the rhizosphere and nodulation were inhibited at pH 4.3 and 4.7.50–1000μM calcium had no effect either on the multiplication of Rhizobium in the range pH 4.3–5.5, or on nodule formation in the absence of aluminium. 50 μM aluminium inhibited, root elongation and root hair formation at pH 4.3 and 4.7; the effect on root elongation was reduced by increasing the calcium concentration from 50 to 1000μM. 50μM aluminium also inhibited Rhizobium multiplication in the rhizosphere and reduced nodule formation at pH 5.5 (at which aluminium precipitated out of solution), but root elongation and root hair formation were unaffected. These, effects of aluminium at pH 5.5 may explain the poor response to inoculation by white clover in acid mineral soils after liming.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02450370
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 41
    Electronic Resource
    Electronic Resource
    Stabilité biologique et comportement physique d'un complexe argilo-humique placé dans différentes conditions de saturation en calcium ou en potassium (1984)
    Springer
    Plant and soil 77 (1984), S. 271-284 
    Details
    ISSN: 1573-5036
    Keywords: Calcium ; Cation de liaison ; Complexes organo-minéraux ; Minéralisation ; Stabilisation de la matière organique ; Structure ; Calcium ; Cation bridge ; Fixation of organic matter ; Mineralisation ; Organomineral compounds ; Structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Summary By gradually removing the exchangeable calcium held by the organo-mineral complex of an organic soil from the Jura mountains, the authors showed: a direct action of the microflora on the mineralisation of organic matter (Fig. 7) and on the generation of mineral nitrogen (Fig. 3); an indirect action by the mineralisation of organic matter on the destabilisation of the clay-humus complex. They therefore concluded that the reduction of calcium resulted in the destabilisation of the organo-mineral complex by H+, produced by the biodegradation of the most labile portion of the organic matter. The clay humus complex gradually dissociated. This process lead to the destruction of aggregates and organo-mineral complexes. The organic matter released became biodegradable due to the shortage of calcium.
    Notes: Résumé Les auteurs sont partis d'un complexe organo-minéral calcique provenant d'un sol humifère du Jura et ont provoqué une diminution progressive au cours du temps du taux de calcium échangeable. L'étude de l'évolution de divers paramètres, menée parallèlement, a permis d'analyser les effets directs et indirects de la baisse du calcium sur le complexe organo-minéral. Les résultats obtenus concernent: 1. les effets directs de l'action minéralisatrice de la microflore sur la dégradation de la matière organique (Fig. 7) et la production d'azote minéral (Fig. 3). 2. les effets indirects de cette minéralisation sur la déstabilisation du complexe argilo-humique (Fig. 8). Ils permettent d'affirmer qu'un complexe organo-minéral calcique évolue très rapidement quand l'apport d'ions calcium vient à diminuer ou à être supprimé. Les ions Ca2+ sont très vite déplacés et remplacés par des ions H+ produits par la biodégradation des fractions les plus labiles de la matière organique. Le complexe argile-calcium-humus est progressivement dissocié. Le processus conduit à une destruction des agrégats avec libération des argiles et de la matière organique qui devient à son tour biodégradable. l'effet stabilisateur du calcium ayant disparu.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02182930
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 42
    Electronic Resource
    Electronic Resource
    Relationships of bio-climatic zones and lithology with various characteristics of forest soils in Greece (1984)
    Springer
    Plant and soil 79 (1984), S. 101-121 
    Details
    ISSN: 1573-5036
    Keywords: Base saturation ; Bio-climatic zones ; Calcium ; Clay accumulation ; Copper ; C:N ratio ; EDTA ; Forest soils ; Greece ; Iron ; Magnesium ; Manganese ; Nitrogen ; Phosphate ; Potassium ; Soil classification ; Zinc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Soils derived from a number of different parent materials (lithologies) and developed along a climatic gradient, manifested by the altitudinal succession of natural vegetation zones (Mediterranean, sub-Mediterranean, Mountainous and Pseudoalpine), were sampled throughout mainland Greece. In soils derived from siliceous parent materials low in clay, acidity increase and percent base saturation decreases from the Mediterranean to the Pseudoalpine vegetation zones. Clay illuviation is found mainly in soils developed in the Mediterranean and the sub-Mediterranean zones. No such changes are apparent in clayey soils rich in bases. Organic matter content of the mineral portion of the soil profile increases by a factor of 2 with a decrease in mean annual air temperature of about 10°C. The pattern of change in clay and soil organic matter content with climate is in relatively good agreement with soil development trends in the area, when soil profiles are named according to the FAO-Unesco soil map of the world. Concentrations of Ca and Mg decrease and those of total N, total and extractable P, K, Fe, Mn and Zn increase from the Mediterranean to the Mountainous zone. Within the same zone, however, concentrations of N, Ca, K, Fe, Mn and Zn decrease, but those of Mg, total and extractable P increase with soil depth. The concentrations of most macro- and micronutrients in the humic horizon are several times higher than those in the mineral portion of the soil profile due to biological enrichment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02182148
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 43
    Electronic Resource
    Electronic Resource
    Vesicular-arbuscular mycorrhizal infection in lettuce (Lactuca sativa) in relation to calcium supply (1984)
    Springer
    Plant and soil 82 (1984), S. 61-67 
    Details
    ISSN: 1573-5036
    Keywords: Calcium ; Glomus caledonium ; Glomus mosseae ; Lactuca sativa ; Vesicular-arbuscular mycorrhiza
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Infection of lettuce roots (Lactuca sativa L.) by the vesicular-arbuscular mycorrhizal fungiGlomus caledonium andGlomus mosseae was dependent on the amount of calcium (supplied as CaCl2·2H2O or CaSO4·2H2O) in the nutrient solution; those plants growing at low calcium concentrations being poorly infected.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02220770
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 44
    Electronic Resource
    Electronic Resource
    Aluminium toxicity expression nutrient uptake, growth and root morphology ofTrifolium repens L. cv. ‘Grasslands Huia’ (1984)
    Springer
    Plant and soil 82 (1984), S. 101-116 
    Details
    ISSN: 1573-5036
    Keywords: Aluminium toxicity ; Calcium ; Phosphate ; Trifolium ; Uptake ; Nutrients
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Hydroponic experiments were undertaken to examine the effect of increasing aluminium levels on the mineral nutrition and root morphology ofT. repens growing in nutrient solution. Toxicity symptoms appear between 27.8 and 47.5 μM Al3+ activity (148 to 297 μM total aluminium). The threshold level corresponding to a 10% reduction in leaf fresh weight is estimated to be approximately 20 μM Al3+ activity. The concentration of aluminium in the leaves of white clover increases exponentially with aluminium activity in the nutrient solution. The uptake of divalent cations was inhibited but aluminium enhanced potassium and nitrogen concentrations in both leaves and roots. At high pH (pH 6.0) the speciation of aluminium is controlled by the formation of solid aluminium phosphate and aluminium hydroxide except at the lowest aluminium level (37 μM) where 99.9 per cent is present as the DTPA complex. As the concentration of total aluminium increases, the percentage of Al-DTPA and soluble aluminium hydroxide decreases whilst solid Al(OH)3 increases rapidly to reach a maximum of 91.6 percent (of the total aluminium) in the 1180 μM aluminium treatment. At pH 4.5 the dominant forms of aluminium are free aluminium ion Al-DTPA, AlSO 4 + and AlOH2+. The roots of aluminium stressed plants showed symptoms typical of aluminium toxicity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02220774
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 45
    Electronic Resource
    Electronic Resource
    Seasonal changes in foliar macronutrients (N, P, K, Ca and Mg) inEucalyptus saligna Sm. andE. wandoo Blakely growing in rehabilitated bauxite mine soils of the Darling Range, Western Australia (1984)
    Springer
    Plant and soil 81 (1984), S. 377-388 
    Details
    ISSN: 1573-5036
    Keywords: Calcium ; Eucalyptus saligna ; Eucalyptus wandoo ; Foliar nutrients ; Magnesium ; Nitrogen ; Phosphorus ; Potassium ; Rehabilitation ; Seasonal trends
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Seasonal changes in the foliar concentration of macronutrients (N, P, K, Ca and Mg) in sapling trees ofEucalyptus saligna Sm. andE. wandoo Blakely growing in rehabilitated bauxite mined areas in the Darling Range of Western Australia are described. Foliar N concentration decreased with age of the fully expanded leaf tissue. Leaf N concentrations were also high when rates of litter decomposition were expected to be high during the period of early spring. The greatest foliar N difference between trees growing in good soil conditions and those from poorer soil conditions also occurred during this period. Levels of P in leaves were highest in young developing leaves but once the leaves reached full size, no seasonal trend in P concentration was observed. Foliar K was lower during the winter and probably related to the period of maximum leaching by precipitation. High foliar K during summer, however, could be related to the role of K in lowering cellular water potential. Leaf Ca was highest during early sping. Low mobility of cellular Ca during the cool portion of the year was indicated. Foliar Mg showed a weak pattern of decreasing concentration with leaf age. The best season for sampling for these broadleafed evergreen species to provide information on plant nutrient status appears to be in spring.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02323052
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 46
    Electronic Resource
    Electronic Resource
    Adsorption and exchange of Ca, Mg and K-ions on the root cell walls of clover and rye-grass (1984)
    Springer
    Plant and soil 80 (1984), S. 181-190 
    Details
    ISSN: 1573-5036
    Keywords: Adsorption ; Calcium ; CEC ; Cell wall ; Clover ; Exchange ; Magnesium ; Model ; Potassium ; pH ; Root ; Rye-grass
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The ion exchange properties of clover and rye-grass root cell walls were studied quantitatively. Three sets of experiments were performed: adsorption of Ca, Mg and K ions versus pH, adsorption versus cation concentration and exchange isotherms Ca−Mg and Mg−K. A model has been developed. It allows the satisfactory prediction of results (except for pH curves) with the adjustment of a minimum of parameters. The total charge (RT), on its own, accounts for the difference between the ion exchange properties of the clover and rye grass cell walls. The selectivities observed on root material are very different from those observed on soil exchange complexes. The decreasing affinities of cell walls for cations follow the sequence: Ca〉Mg≫K for cell walls. These differences of selectivity are much larger than those usually observed for soil exchange complexes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02161174
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 47
    Electronic Resource
    Electronic Resource
    Foliar and twig macronutrients (N, P, K, Ca and Mg) in selected species ofEucalyptus used in rehabilitation: sources of variation (1984)
    Springer
    Plant and soil 81 (1984), S. 363-376 
    Details
    ISSN: 1573-5036
    Keywords: Branch nutrients ; Calcium ; Eucalyptus saligna ; Eucalyptus wandoo ; Foliar nutrients ; Magnesium ; Nitrogen ; Phosphorus ; Potassium ; Rehabilitation ; Soil nutrients
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The macronutrient variation within four 6 year oldEucalyptus saligna and four 5 year oldE. wandoo growing on rehabilitated bauxite pits was determined. Significant differences in mean nutrient concentrations were generally recorded between good soil condition sites and poor soil sites, between tree individuals, branch height, and plant organ type; but mean nutrient values were not different among canopy aspects. Fully expanded leaves of the current year provided the most uniform nutrient levels among the plant organs and showed major differences between sites with good soil nutrient conditions and those with poor conditions. Differences in foliar and branch levels of N, P, K, Ca and Mg, the variation between sites, canopy heights and plant organ types, and the use of foliar nutrient levels to indicate deficiencies are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02323051
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 48
    Electronic Resource
    Electronic Resource
    Application of the short-time staining for the electron microscopic investigation of the crystallization of polyethylene (1983)
    Springer
    Colloid & polymer science 261 (1983), S. 373-374 
    Details
    ISSN: 1435-1536
    Keywords: Electron microscopy ; short-time staining ; nodular structure ; crystallization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01413947
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 49
    Electronic Resource
    Electronic Resource
    Oral 1,25(OH)2D3: An effective prophylactic treatment for glucocorticoid osteopenia in rats (1983)
    Springer
    Calcified tissue international 35 (1983), S. 107-110 
    Details
    ISSN: 1432-0827
    Keywords: Calcium ; Glucocorticoid ; Vitamin D ; Osteoporosis ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Eighty-eight adult male Sprague-Dawley rats were given a diet with either (a) 0.5% Ca and 0.6% P or (b) 0.01% Ca and 0.6% P. Osteopenia was created by adding prednisolone to the diet. The prophylactic effect of oral 1,25(OH)2D3 on the osteopenia was studied. It was found that prednisolone osteopenia in the rat was associated with defective Ca absorption. By giving an oral dose of 1,25(OH)2D3, it was possible to maintain normal Ca absorption during prednisolone treatment and to prevent the bone loss. No significant hypercalcemia or any kidney calcifications were seen. These results are in contrast to earlier findings, in which subcutaneous administration of 1,25(OH)2D3 failed to prevent prednisolone osteopenia because of its tendency to increase bone resorption.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02405014
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 50
    Electronic Resource
    Electronic Resource
    31P nuclear magnetic resonance spectroscopic evidence for ternary complex formation of fetal dentin phosphoprotein with calcium and inorganic orthophosphate ions (1983)
    Springer
    Calcified tissue international 35 (1983), S. 815-818 
    Details
    ISSN: 1432-0827
    Keywords: 31P NMR spectroscopy ; Phosphoprotein ; Dentin ; Calcium ; Inorganic orthophosphate ; Bovine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The single phosphoprotein of fetal calf dentin, having a molecular weight of approximately 94,000 and a phosphorus content of 8% (w/w), was examined by31P NMR spectroscopy. The single resonance at 3.7 ppm at pH 10 and its chemical shift during acid titration established the phosphomonoester nature of the organic phosphorus moiety. During titration of the phosphoprotein with CaCl2 in the presence of inorganic orthophosphate ions, line broadening for the orthophosphate resonance was both phosphoprotein- and calcium-dependent, indicating ternary complex formation. The data indicate that the phosphoprotein of fetal calf dentin binds both calcium and inorganic orthophosphate ions and therefore has the requisite physical chemical properties necessary for it to facilitate the heterogeneous nucleation of a Ca-PO4 solid phase from solution during tissue mineralization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02405129
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 51
    Electronic Resource
    Electronic Resource
    Characterisation of the Egeria densa Planch. leaf symplast (1983)
    Springer
    Planta 158 (1983), S. 320-328 
    Details
    ISSN: 1432-2048
    Keywords: Calcium ; Egeria ; Fluorescent probe ; Ions, group II ; Symplast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The hydrophyllic dyes fluorescein glutamic acid, fluorescein glutamylglutamic acid (F(Glu)2), fluorescein hexaglycine, fluorescein leucyldiglutamyl-leucine and 6-carboxyfluorescein are unable to pass the plasmalemma in leaves of E. densa. However, when injected into single cells the dye conjugates of molecular weight 665 dalton or less move freely from cell-to-cell. This intercellular movement presumably occurs via the plant symplast. Movement of F(Glu)2 from the injected cell occurs with greatly reduced frequency when Ca2+, Mg2+ or Sr2+ are injected into the cell immediately prior to the dye. The fraction of dye injections leading to movement declines with increasing group II ion concentration in the electrode tip, up to 10 mM. Sodium and K ions do not affect dye movement. When dye injection is delayed 30 min after Ca2+ injection, dye movement is no longer inhibited. Thus the cells recover from the Ca2+ injection, indicating that the ion does not cause major cell damage. Recovery from Mg2+ injection is not complete within 60 min. Treatment of leaves with chemicals expected to raise the concentration of free intracellular group II ions, notably the mitochondrial uncoupler carbonyl cyanide p-trifluoromethoxyphenyl hydrazone, the inhibitor of mitochondrial Ca2+ uptake trifluralin, or the ionophore A23187 also inhibits dye movement, while the calmodulin inhibitor trifluoperazine does not. Cytoplasmic streaming is inhibited by Ca2+ or Mg2+ injection and by the metabolic inhibitors. However when streaming is stopped by cytochalasin B, dye movement is not inhibited. Hence steaming is not necessary for dye movement. Thus the cytoplasmic concentration of free group II ions may directly regulate the permeability of the plant symplast.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00397334
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 52
    Electronic Resource
    Electronic Resource
    Physical map of the mitochondrial DNA from the phycomycete Allomyces macrogynus including the position of the ribosomal RNA genes and of an intervening sequence in the large rRNA gene (1983)
    Springer
    Current genetics 7 (1983), S. 327-333 
    Details
    ISSN: 1432-0983
    Keywords: Allomyces macrogynus ; Mitochondrial DNA ; Electron microscopy ; Restriction enzyme map
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The mitochondrial (mt) DNA of the aquatic phycomycete Allomyces macrogynus is a circular molecule with a size of 56.1 kbp. The cleavage sites for the restriction enzymes SalI and PvuI were mapped by comparing the partial denaturation patterns of isolated restriction fragments with the pattern of the intact circle. The genes coding for the small and large ribosomal RNA (rRNA) were located on the restriction map by heteroduplex and R-loop analysis. The gene coding for the large rRNA contains an intervening sequence, app. 0.7 kbp in size, near the 3′-end of the gene. The two rRNA genes are encoded on the same strand of the mtDNA and separated by a region of 17–18 kbp. This rRNA gene organization is similar to that found with members of the Ascomycetes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00445871
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 53
    Electronic Resource
    Electronic Resource
    Electron microscopy of photosynthetic membranes containing bacteriochlorophyll b (1983)
    Springer
    Archives of microbiology 135 (1983), S. 169-175 
    Details
    ISSN: 1432-072X
    Keywords: Photosynthetic membranes ; Electron microscopy ; Image processing ; Ectothiorhodospira halochloris ; Ectothiorhodospira abdelmalekii ; Rhodopseudomonas viridis ; Rhodopseudomonas sulfoviridis ; Thiocapsa pfennigii
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The photosynthetic membranes of the five bchl b-containing bacteria Ectothiorhodospira halochloris, E. abdelmalekii, Rhodopseudomonas viridis, R. sulfoviridis and Thiocapsa pfennigii have been investigated by electron microscopy and digital image analysis. All five species have the photosynthetic complexes hexagonally arrayed in the membrane with lattice spacings close to 13 nm, except for R. sulfoviridis and T. pfennigii which display somewhat smaller (∼12.5 nm) lattice spacings. Correlation averaging which imposes less stringent requirements on the lattice perfection than conventional Fourier filtration techniques has been employed to elucidate the structure of the photosynthetic complexes. Their basic organization, i.e. a ring, probably containing the light-harvesting (LH) polypeptides, surrounding a core (the “reaction centre”) appears to be almost identical for all species under scrutiny. Despite a resolution of ∼1.6 nm, however, little further significant substructure can be deduced from the averages; possible reasons for the “blurred” appearance of the LH-ring and absence of any subdivision in the reaction centre are discussed along with strategies aimed at obtaining a more detailed model of the molecular architecture of the photosynthetic membranes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00414474
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 54
    Electronic Resource
    Electronic Resource
    A fully automated and computerized system for simultaneous measurements of motility and phototaxis in Chlamydomonas (1983)
    Springer
    Archives of microbiology 135 (1983), S. 259-264 
    Details
    ISSN: 1432-072X
    Keywords: Phototaxis ; Motility ; Flagellate ; Chlamydomonas ; Sodium azide ; Calcium ; A 23 187
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A fully automated and computerized method for simultaneous measurements of motility and phototaxis of unicellular flagellates is described. Both systems are directly coupled with a homocontinuous culture. The motility measuring apparatus is equipped with a video camera and recorder for simultaneous single cell behaviour studies. First results of studies on the effects of the phototaxis inhibitor sodium azide and the Ca2+ conducting ionophore A23 187 on motility and phototaxis of Chlamydomonas are reported and correlated with video observations. These results demonstrate that the described systems give informations of whether phototaxis or motility or both are inhibited by chemicals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00413478
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 55
    Electronic Resource
    Electronic Resource
    Phototaxis in the gliding flagellate, Euglena mutabilis (1983)
    Springer
    Archives of microbiology 135 (1983), S. 25-29 
    Details
    ISSN: 1432-072X
    Keywords: Electron microscopy ; Euglena mutabilis ; Flagellate ; Photomovement ; Photoreceptor ; Phototaxis ; Single-cell analysis ; Videomicroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Due to the lack of an emergent flagellum the green flagellate Euglena mutabilis is restricted to gliding motility. During forward movement, the organisms orient positive phototactically in the presence of a suitable light stimulus. The cell contains both a stigma and a paraflagellar body which differ in shape and size from the organelles found in E. gracilis. The degree of orientation in white light follows an optimum curve with a maximum at about 100 lx. The spectral sensitivity shows a number of prominent peaks in the blue and green regions and extends well into the red region of the visible spectrum. Since the cell does not rotate during locomotion a periodic shading mechanism cannot account for phototactic orientation. Thus, phototaxis in the related species, E. gracilis and E. mutabilis differ in their photoreceptor molecules, their sensory transduction chains and their strategies of light direction detection.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00419477
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 56
    Electronic Resource
    Electronic Resource
    Development of the granule population in neutrophil granulocytes from human bone marrow (1983)
    Springer
    Cell & tissue research 234 (1983), S. 469-496 
    Details
    ISSN: 1432-0878
    Keywords: Bone marrow (human) ; Neutrophil granulocyte ; Granules ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Bone marrow from hematologically healthy adults was exposed to a number of fixation procedures for investigation of the heterogeneity of the granule population in neutrophil granulocytes at the ultrastructural level. Four main cell stages were distinguished: early promyelocyte, late promyelocyte, myelocyte, and mature neutrophil granulocyte and described separately; metamyelocytes and band-form or stab cells are described together. The characteristic changes in the cytoplasm during myelopoiesis were analysed quantitatively. Special attention was given to the development of the granule population. Three types of granule arise in successive cell stages: granules which develop a sub-structure in the matrix (nucleated granules) are formed in early promyelocytes, granules with a homogeneous electron-dense matrix (azurophil granules) in late promyelocytes, and granules with a less electron-dense matrix (specific granules) in myelocytes. The three types of granule remain present during myelopoiesis. The best results in distinguishing the granule types were obtained by prefixation either in 0.1% glutaraldehyde or in 1.5% glutaraldehyde followed by washing in phosphate-buffered Ringer solution to which aminotriazole had been added. Granule counts revealed for the mature neutrophil a total number of granules of about 220 per ultrathin section. This population of granules is composed of about 12% nucleated, 11% azurophil, and 77% specific granules. When our previous findings are taken into account, the existence of three successively formed and morphologically distinguishable types of granule in heterophil (neutrophil) granulocytes has been demonstrated for three mammalian species: the guinea pig, the rat, and man. A separate term for the early promyelocyte stage is proposed: eomyelocyte.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00218646
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 57
    Electronic Resource
    Electronic Resource
    Light-related changes in electron-dense material in photoreceptor synaptic clefts of the frog, Rana catesbeiana (1983)
    Springer
    Cell & tissue research 234 (1983), S. 579-593 
    Details
    ISSN: 1432-0878
    Keywords: Rods ; Cones ; Retina ; Bullfrog ; Synapse ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Lumps of electron-dense material were observed in synaptic clefts associated with all types of photoreceptors, in the vicinity of the synaptic ribbons, in the retinae of dark-adapted frogs. Frogs were reared under a cyclic illumination (light on at 8:00; light off at 20:00) and then exposed to one of two courses of dark adaptation: one started from 11:00 in the morning, and the other started from 20:00 in the evening. The synaptic clefts of red rods became wider at some places where spherical or polygonal lumps of dense material were accumulated. The frequency and sectional area of the lumps increased faster for the first hour in the regime starting from 20:00 than in the regime starting from 11:00, then they reached the similar saturation levels of about 0.6 (per ribbon) and 1.6 to 1.8×104 (nm2) in both the regimes. In greenrod synapses, plate-shaped lumps of dense material were present in synaptic clefts and interspaces between the processes of second-order neurons. In cone synapses at the end of about 1 h darkness, the frequency and area of the lumps reached maximum values of about 0.12 (per ribbon) and 9×103 (nm2) in the regime starting from 11:00 and, about 0.08 (per ribbon) and 4 × 103 (nm2) in the regime starting from 20:00. On exposure to light, the dense material abruptly disappeared from all types of photoreceptor synaptic clefts. Large dense-core vesicles, occasionally observed in light-adapted rod photoreceptor terminals, seem to participate in exocytosis of the dense material. The number of dense-core vesicles per synaptic ribbon in a terminal was about 0.55 at the end of 3 h light in the morning and about 1.28 at the end of 12 h light in the evening. The increased number of dense-core vesicles during the daytime may contribute to the faster accumulation of dense material in the synaptic clefts. Although the chemical identification or the functional significance of the electron-dense material remains unknown, it is interesting that this material showed a rise and fall in response to darkness and illumination. Also the fact that this material is clearly visible will be helpful for future analysis of frog photoreceptor synapses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00218653
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 58
    Electronic Resource
    Electronic Resource
    Double membrane-bounded intestinal microvilli in Oncopeltus fasciatus (1983)
    Springer
    Cell & tissue research 232 (1983), S. 593-600 
    Details
    ISSN: 1432-0878
    Keywords: Peritrophic membrane ; Insect ; Microvilli ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A double plasma membrane (DPM) surrounding intestinal microvilli of the migratory milkweed bug, Oncopeltus fasciatus, is described. Mutant and wild types of the phytophagous insect have been studied by conventional SEM and TEM procedures with the use of membrane-enhancing staining methods. Longitudinal and transverse sections revealed a DPM surrounding microvilli and continuing over the apical portions of the intestinal cell. The outer membrane of the DPM contributes to an intestinal lining or peritrophic membrane (PTM), which apparently accumulates in layers. SEM studies reveal a rugose intestinal surface and complete PTM in both starved and fed insects. Only rarely are exposed microvilli seen by SEM. SEM examinations also enable the observation of numerous blebs on the luminal side of the PTM apparently held in position by a neck-like attachment and apparently derived from the outer membrane of the DPM. Preliminary TEM studies of microvilli revealed unique microvesicle-like structures, lying just inside the inner membrane of the DPM, which may be of membrane origin based on their typical trilaminar appearance after en bloc staining with uranyl acetate. Highly ordered microfilaments were observed to occupy the most central aspect of the microvilli.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00216431
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 59
    Electronic Resource
    Electronic Resource
    Ultrastructural characteristics of vasopressin-containing neurons in the paraventricular nucleus of the hypothalamus (1983)
    Springer
    Cell & tissue research 234 (1983), S. 125-134 
    Details
    ISSN: 1432-0878
    Keywords: Vasopressin ; Immunocytochemistry ; Electron microscopy ; Hypothalamus ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Vasopressin-containing neurons, identified by immunocytochemistry, are located predominantly in the posterior magnocellular division of the paraventricular nucleus of the rat hypothalamus. By electron microscopy, the immunoreaction product is seen within the cell bodies and neuronal processes. In the perikarya and dendritic processes, the immunoreactive material is associated primarily with neurosecretory granules. Axonal processes, identified by their content of microtubules and accumulation of neurosecretory granules, show the immunoreaction product in association with both of these organelles. Afferent axo-dendritic, axo-somatic and putative axo-axonic synapses with immunostained vasopressinergic neurons can be identified. The presynaptic profiles do not contain immunoreactive material. This study contributes to the ultrastructural characterization of vasopressinergic neurons in the paraventricular nucleus and of their afferent synaptic input.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00217406
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 60
    Electronic Resource
    Electronic Resource
    Laminated figures of the intercisternal regions of dictyosome-like structures from guinea-pig spermatocytes fixed with glutaraldehyde-tannic acid (1983)
    Springer
    Cell & tissue research 234 (1983), S. 633-639 
    Details
    ISSN: 1432-0878
    Keywords: Dictyosome-like structures ; Golgi apparatus ; Phosphatidylcholine ; Laminated figures ; Electron microscopy ; Guinea pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Dictyosome-like structures (DLS) of guinea pig spermatocytes, when prefixed in mixtures of glutaraldehyde and tannic acid, exhibited laminated figures with a repeating periodicity of about 4.5 nm in the spaces between DLS saccules or in association with the surfaces of the DLS saccules. These laminated figures were similar to those figures derived from saturated lipids in other tissues. Alternatively, spaces between saccules were collapsed leaving only thin, electron-dense material separating adjacent saccules. These changes were not observed when the DLS were prefixed in glutaraldehyde before exposure to tannic acid. The presence of laminated figures following fixation with tannic acid and osmium tetroxide suggests that saturated lipids are present in, or associated with, the intersaccular regions of the DLS. The distribution of laminated figures in other membrane structures was not affected by post fixation with tannic acid nor were laminated figures comparable to those of the DLS observed between cisternae of the Golgi apparatus. These results support previous conclusions that DLS are distinct from Golgi apparatus and are a unique component of the germ cell cytoplasm.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00218656
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 61
    Electronic Resource
    Electronic Resource
    Evidence for the role of Ca2+ ions in tip extension in pollen tubes (1983)
    Springer
    Protoplasma 115 (1983), S. 11-17 
    Details
    ISSN: 1615-6102
    Keywords: Pollen tubes ; Calcium ; Tip extension ; Vesicle fusion ; Microfilaments
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Pollen tube growth is shown to be inhibited by both suboptimal (〈10−4 M) and supraoptimal (〉10−3 M) Ca2+ ion concentrations. Tip extension rates are independent of Ca2+ ion concentration over the optimal range. Changes in the structure of the tips of pollen tubes after transfer to inhibitory Ca2+ ion conditions provide evidence in support of our proposed mechanism of pollen tube tip growth (J. theor. Biol.98, 15–20, 1982). It is clearly demonstrated that tip extension is controlled, not only by the rate of vesicle fusion, but also by the state of plasticity of the tip; these processes appear to be sensitive to changes in Ca2+ ion concentration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01293575
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 62
    Electronic Resource
    Electronic Resource
    Ultrastructural studies on the food vacuole cycle of a heliozoon (Feeding byActinophrys, III) (1983)
    Springer
    Protoplasma 115 (1983), S. 43-51 
    Details
    ISSN: 1615-6102
    Keywords: Digestion ; Membrane flow ; Electron microscopy ; Sarcodina ; Actinophrys sol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The digestion of food in the heliozoonActinophrys sol is characterized by several distinct membrane events. Initially, extrusomes expand and fuse with each other and with the plasma membrane providing the membrane for the nascent food vacuole. During this process a—presumably lytic—material is secreted. After complete forming of the food vacuole a second type of vesicles fuses with it, whereupon usually lysis of the prey occurs. After denaturation and coagulation of the food, fluid is removed from the food vacuole. This process is accompanied by a high cytotic activity around the periphery of the food vacuole. Following this step, the perinuclear Golgi region shows an active appearance and numerous lysosomes fuse with the food vacuole. In consequence of this the food is degradated. The food vacuole shrinks continuously. Simultaneously vesicles filled with the digested material pinch off from the food vacuole, the content of which shows a more and more condensed mass of undigestible material. The undigestible residues are defecated eventually. The process of digestion is accompanied by an increase in volume and number of electron lucent cytoplasmic vacuoles. These vacuoles gradually become filled with a filamentous material starting with the vacuoles in the cell periphery. As the digestion continues, the vacuolar contents become condensed successively. Synchroneously the vacuoles move towards the cell center. After completion of the digestion, the cytoplasmic vacuoles decrease in volume and number and do not show any longer electron dense contents.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01293579
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 63
    Electronic Resource
    Electronic Resource
    Thylakoid degradation during photooxidative bleaching of the cyanobacteriumAnacystis nidulans (1983)
    Springer
    Protoplasma 115 (1983), S. 202-207 
    Details
    ISSN: 1615-6102
    Keywords: Anacystis nidulans ; Cyanobacterium ; Electron microscopy ; Freeze-fracmres ; Thylakoid degradation ; Ultrathin-sections
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Photooxidative bleaching of the CyanobacteriumAnacystis nidulans was studied by electron microscopic investigation of both freezefractured and thin-sectioned samples. During bleaching four consecutive phases in degradation of photosynthetic membranes (thylakoids) could be characterized: 1. No ultrastructural changes until photosystem II activity is lost. 2. Derangement of characteristic arrangement of thylakoids. 3. Thylakoids visible only in thin-sectioned but not in freeze-fractured samples. 4. Completely bleached cells, only traces in place of former thylakoids visible in thinsectioned samples. Bleaching did not cause lysis of the cells showing that the cytoplasmic membrane was not damaged. Polyhedral bodies also were still detectable in bleached cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01279810
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 64
    Electronic Resource
    Electronic Resource
    A technique for optical and electron microscopy of isolated plant chromosomes (1983)
    Springer
    Protoplasma 116 (1983), S. 198-200 
    Details
    ISSN: 1615-6102
    Keywords: Chromosome isolation ; Electron microscopy ; Vicia faba ; Vicia narbonensis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Using a formalin fixation technique whole chromosomes from root tips ofVicia species were isolated into a buffer solution. Combining this technique with the use of a set of reciprocal translocations available for this species—Vicia faba— allowed each member of the karyotype to be isolated and identified. Such isolated chromosomes can be used for optical microscopy or for either transmission or scanning electron microscopy where critical point drying clearly reveals chromatin fibre.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01279838
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 65
    Electronic Resource
    Electronic Resource
    Characterization of the parapharyngeal mass of the ciliateHomalozoon vermiculare (1983)
    Springer
    Protoplasma 116 (1983), S. 209-212 
    Details
    ISSN: 1615-6102
    Keywords: Parapharyngeal mass ; Electron microscopy ; Cytochemistry ; Electron microprobe X-ray analysis ; Ciliate ; Homalozoon vermiculare
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The structure and elemental composition of the granules which make up the parapharyngeal mass of the ciliateHomalozoon vermiculare are analyzed. The mass is made up of two kinds of granules. One is not membrane-bounded and is composed of paraglycogen. The second type is comprised of concentric lamellae. It is rich in magnesium, phosphorus, potassium, and calcium. These results do not support the contention that the granules are directly involved in the process of food vacuole formation. The role of the parapharyngeal mass remains obscure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01279841
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 66
    Electronic Resource
    Electronic Resource
    Electron microscopy of dry peanut (Arachis hypogaea L.) seeds crushed for oil removal. Fixation and embedding of anhydrously prepared tissues (1983)
    Springer
    Protoplasma 117 (1983), S. 1-6 
    Details
    ISSN: 1615-6102
    Keywords: Cell walls ; Electron microscopy ; Moisture ; Plastic embedding ; Seeds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Aqueous fixatives caused dry seed tissues to swell; mashed peanuts, crushed to remove oil, swelled even more. Use of anhydrous, organic solvents as vehicles for fixatives enabled maintenance of dimensional stability during fixation of dry seed tissues; even crushed seed tissue did not swell significantly when processed anhydrously. However, anhydrously processed specimens proved difficult to section. The difficulty was due to imperfect permeation of plastic into the seed tissues during embedding. An explanation of why anhydrously processed dry seed tissues are so difficult to embed in plastic is offered.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01281778
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 67
    Electronic Resource
    Electronic Resource
    The effect of ionophore A 23187 and ruthenium red on tentacle contraction and ultrastructure inDiscophrya collini: Evidence of calcium fluxing from intracellular reservoirs (1983)
    Springer
    Protoplasma 117 (1983), S. 158-166 
    Details
    ISSN: 1615-6102
    Keywords: Calcium ; Contraction ; Discophrya ; Ionophore A 23187 ; Ruthenium red ; Tentacle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The suctorian protozoonDiscophrya collini has contractile tentacles with microfilaments and a central microtubule-lined canal (axoneme). The role of calcium fluxing in tentacle contraction has been investigated using the Ca2+ ionophore A 23187 and ruthenium red (RR), a known inhibitor of certain Ca2+ membrane transport events. Treatment with CaCl2 alone caused tentacle contraction with a threshold at 5 × 10−3 M CaCl2 and a maximum at 5 × 10−2 M CaCl2 with contraction to 32.8% of the original length. In the presence of 5 μM ionophore A 23187 the threshold was lowered to 5 × 10−6 M CaCl2 with a maximum to 19.6% original length at 5 × 10−2 M CaCl2. A 23187 alone induced contraction with a threshold of 3.0 μM and a maximum to 30.5% original length at 10 μM A 23187. Treatment with RR alone had little effect on tentacle length. However, a 10 μM A 23187-induced contraction was partially counteracted by the simultaneous application of RR with a threshold at 2 μM RR and a maximum at 8 μM RR. Removal of the ionophore after induced tentacle contraction resulted in partial re-extension, which was inhibited by RR. Ultrastructural observations indicated that the ionophore and CaCl2-induced contraction processes are indistinguishable. The CaCl2/ionophore treatments led to axonome disruption, interpreted as a consequence of supranormal levels of intracellular Ca2+. X-ray microanalysis of cytoplasmic membrane-bound elongate dense bodies (EDB) showed a high level of Ca2+ in CaCl2-treated cells, little Ca2+ in ionophore-treated cells and intermediate levels in the RR-treated, ionophore/RR-treated and untreated control cells. It is suggested that A 23187 enhances both the uptake of extracellular Ca2+ and the release of Ca2+ from the EDB, the latter being counteracted by RR. These observations support the proposal that the EDB act as Ca2+ reservoirs, and that their Ca2+ fluxing moderates cytosolic Ca2+ levels which mediate a Ca2+-dependent tentacle contraction mechanism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01288354
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 68
    Electronic Resource
    Electronic Resource
    Membrane-associated calcium during pollen grain germination: a microfluorometric analysis (1983)
    Springer
    Protoplasma 117 (1983), S. 226-232 
    Details
    ISSN: 1615-6102
    Keywords: Calcium ; Calmodulin ; Chlorotetracycline ; Microfluorometry ; Phenothiazine ; Pollen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Pear (Pyrus communis L.) pollen was germinated and grown in hanging drop cultures containing phenothiazine drugs, trifluoperazine and chlorpromazine, potent inhibitors of the Ca2+-calmodulin complex. Responses for the two drugs were similar: at 1.0–2 10.0 ΜM pollen germination and tube growth were inhibited. Inhibition of tube growth was not uniform; at 10.0 ΜM growth of about half of those tubes which had germinated was inhibited while the remaining half of the population grew normally. This bimodal distribution of tube growth was noted, but to a lesser extent, at lower concentrations of the drugs as well. Microfluorometric analysis of membrane calcium using chlorotetracycline, a fluorescent chelate probe for membrane calcium, revealed that upon pollen grain hydration there was a sharp decrease in the concentration of calcium associated with membranes and that membrane calcium became localized primarily at the periphery of the newly hydrated pollen grain. Prior to germination there was a reloading of calcium onto membranes in the region of the germination aperture through which the pollen tube would emerge. The release of Ca2+ from membrane sites upon hydration was partially inhibited by treatment with 10 ΜM trifluoperazine. Distribution of membrane calcium in populations of the inhibitor-treated pollen grains was not bimodal however; approximately half of the population had CTC-fluorescence emissions exceeding the maximum value found in the control population. These results suggest that there is a maximum concentration of membrane-associated calcium consistent with normal pollen germination and tube growth and that phenothiazines interfere with the unloading of Ca2+ from membrane sites.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01281826
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 69
    Electronic Resource
    Electronic Resource
    The search for and interpretation of genetic controls that enhance plant growth under deficiency levels of a macronutrient (1983)
    Springer
    Plant and soil 72 (1983), S. 335-350 
    Details
    ISSN: 1573-5036
    Keywords: Calcium ; Nutrient stress ; Phosphorus ; Potassium ; Root growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Techniques developed to measure growth of tomatoes and beans under limiting amounts of either P, K or Ca in solution culture reveal differences among strains. Genetic analysis permits estimates of gene action for control of efficiency and the isolation of improved segregants. The genetic isolates have value in studying mechanisms contributing to uptake, transport and utilization processes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02181972
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 70
    Electronic Resource
    Electronic Resource
    Studies on the possible role of cation exchange capacity in the soil preference of mosses (1983)
    Springer
    Plant and soil 70 (1983), S. 77-93 
    Details
    ISSN: 1573-5036
    Keywords: Adsorption ; Calcium ; Calcium carbonate ; Cation Exchange Capacity ; Hydrogen ; Magnesium ; Moss ; pH ; Potassium ; Sodium ; Soil preference
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Moss species with a different soil preference with respect to its acidity and carbonate content also differ in their cation exchange capacity (leaf, stem, rhizoid), the acidiphile-calcifuges having lower C.E.C. values than the neutrophile-calcicoles. The higher the C.E.C. value, the more the divalent cations calcium and magnesium tend to be adsorbed as compared to the monovalents sodium and potassium, from an equinormal tetracationic solution. The increase in divalent adsorption is mainly due to calcium. Considering this differential adsorption of calcium and in view of data in literature on membrane characteristics, it appears that among the studied cations calcium is an important factor in the observed soil preference through its presence in the cell wall adsorbed fraction and thus in the membrane environment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02374752
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 71
    Electronic Resource
    Electronic Resource
    Taxonomic character of plant species in absorbing and accumulating alkali and alkaline earth metals grown in temperate forest of Japan (1983)
    Springer
    Plant and soil 70 (1983), S. 367-389 
    Details
    ISSN: 1573-5036
    Keywords: Alkali metals ; Alkaline earth metals ; Barium ; Calcium ; Ceasium ; Lithium ; Magnesium ; Potassium ; Rubidium ; Sodium ; Strontium ; Temperate forest
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Absorption and accumulation of alkali (Li, Na, K, Rb, Cs) and alkaline earth (Mg, Ca, Sr, Ba) metals were investigated as taxonomic characteristics (in 62 plant species). Leaf and soil samples were collected from 9 sites in temperature forest in Japan and the above mentioned elements were analyzed. Considerable differences were found among species in their ability to accumulate alkali and alkaline earth metals. Very high concentrations of Li (45 ppm, D.W.), K (37×103 ppm), Rb (159 ppm) and Cs (8.2 ppm) were detected inLastrea japonica which were about 412, 12, 27 and 6 times higher than those of the species with the lowest concentrations. Na content was high inAcer micranthum (358 ppm) which was 16 times higher than species with the lowest concentration. Other species containing high levels of alkali metals wereHydrangea macrophylla, Struthiopteris niponica, Clethra barbinervis. Mean discrimination ratio (D.R.) for all investigated plant species for Li, Na, Rb, and Cs to K were 1.7, 0.44, 0.9 and 1.8 respectively. High concentrations of alkaline earth metals Ca (36×103 ppm), Sr (345 ppm), and Ba (241 ppm) were found in the leaves ofHydrangea paniculata which were about 31, 84, and 72 times higher than those for the species with the lowest concentration. Mg was very high inStruthiopteris niponica (83×102 ppm). Other species with high concentrations of alkaline earth metals belonged to the genus Viburnum. Mean D.Rs. for Mg, Sr, and Bavs Ca were 1.0, 0.7 and 0.08. Principal component analysis of interrelationships between the mineral content in leaf tissues indicated that these elements could be classified into 2 groups with respect to their accumulation behavior in plants. The alkali metals K, Li, Rb, and Cs behaved similarly in their accumulation in leaves but Na behaved independently. Alkaline earth metals Ca, Mg, Sr, and Ba were also found to behave similarly in their accumulation. Factors scores of 1st and 2nd components revealed three groups of plant species: alkaliphilic, alkaline earthphilic, and neutral (non-accumulators).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02374893
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 72
    Electronic Resource
    Electronic Resource
    Ionic interactions in rice plants from dilute solutions (1983)
    Springer
    Plant and soil 70 (1983), S. 309-316 
    Details
    ISSN: 1573-5036
    Keywords: Calcium ; Ionic interaction ; Magnesium ; Nutrient solution ; Oryza sativa L. ; Phosphorus ; Potassium ; Rice
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Ionic interactions may occur as cation-cation interactions, anion-anion interactions, or cation-anion interactions. Greater knowledge of this subject is warranted, due to the intensification of agriculture, in devising efficient fertilization systems. The present study was undertaken to elucidate the interaction among P, K, Ca and Mg absorption by the intact rice (Oryza sativa L.) plants from dilute solutions. The uptake of P was independent of Ca concentrations up-to 250 μM Ca but-there was a small decrease at the higher concentrations. Absorption of K and Mg was stimulated in the presence of Ca ions at low concentrations. But K and Mg absorption was decreased at higher Ca concentrations. Increasing concentrations of K in the nutrient solution depressed P and Ca uptake. Magnesium uptake was stimulated at lower concentrations of K, but at higher concentrations it was also decreased. Similarly, absorption of K and Ca was also decreased with increasing concentrations of Mg. Magnesium at lower concentrations stimulated P uptake but at higher concentraions it was decreased. In the present study maximum growth of rice plants was achieved at about 250μM Ca, 260 μM K, and 33μM Mg in the nutrient solution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02374887
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 73
    Electronic Resource
    Electronic Resource
    Plant genotype differences in the uptake, translocation, accumulation, and use of mineral elements required for plant growth (1983)
    Springer
    Plant and soil 72 (1983), S. 175-196 
    Details
    ISSN: 1573-5036
    Keywords: Boron ; Calcium ; Copper ; Genotypic differences ; Iron ; Magnesium ; Manganese ; Mineral nutrition ; Molybdenum ; Nitrogen ; Phosphorus ; Plant adaptation ; Plant breeding ; Potassium ; Zinc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Plant genotypes differ in their uptake, translocation, accumulation, and use of mineral elements. Examples of genotype differences to iron, nitrogen, phosphorus, potassium, calcium, magnesium, manganese, boron, copper, zinc, and molybdenum are discussed. Current knowledge is sufficient to indicate that many crop plants can be improved for the efficient use of mineral elements and better adaptation to mineral stress conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02181957
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 74
    Electronic Resource
    Electronic Resource
    Nutrient inflows into apple roots (1983)
    Springer
    Plant and soil 71 (1983), S. 371-380 
    Details
    ISSN: 1573-5036
    Keywords: Apple ; Calcium ; Copper ; Iron ; Irradiance ; Magnesium ; Manganese ; Nitrogen ; Nutrient uptake rate ; Phosphorus ; Potassium ; Scion effects ; Season ; Source of nitrogen ; Temperature ; Tissue nutrient level ; Zinc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The rates of uptake of nutrients from solution by apple roots were measured (a) in a root laboratory, using intact roots of mature trees growing under field conditions and (b) in controlled environment using young trees. Maximum nitrate inflows into Discovery/M.9 roots under field conditions were only slightly lower than those into roots of the same genotype in controlled environment, but up to 80 times lower than those into roots of Worcester Pearmain seedlings. At any given external P concentration, P inflows into roots of field-grown trees were about 2.5-times lower than those into the roots of young trees in controlled environment. Nitrate inflows were constant above a solution concentration of 20 mmol m−3 in both field-grown and small trees. In both cases, phosphate inflows increased linearly with solution concentration up to 10 mmol m−3. Among the various plant and environmental factors influencing nutrient uptake characteristics of apple roots were: the scion genotype, tissue nutrient levels, root origin, the form in which N is supplied, level of irradiance of the shoot, root temperature and the season of the year. The effects of these factors are illustrated with examples.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02182678
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 75
    Electronic Resource
    Electronic Resource
    Nutritional differentiation within the speciesDittrichia viscosa W. Greuter, between a population from a calcareous habitat and another from an acidic habitat (1983)
    Springer
    Plant and soil 72 (1983), S. 297-303 
    Details
    ISSN: 1573-5036
    Keywords: Calcicole ; Calcifuge ; Calcium ; Dittrichia viscosa ; Magnesium ; Potassium ; Sodium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Dittrichia viscosa is a Mediterranean bush widespread on various soil types. It is shown that the plants from a calcareous habitat (G plants) and those from an acidic habitat (M plants) differ in their ability to accumulate various cations when growing in the same experimental conditions. On this acidic soil the G plants accumulate more Ca and less K than the M plants. On a calcareous soil the response is reversed; it is the M plants which contain more Ca and often less K. This behaviour on each of the soils is typically that of a calcifuge for M and a calcicole for G. The two types of plants also differ in their affinity for Mg and Na. The ubiquity of the species could well be explained at least partially by genetic differentiation in the ability of plants to select ions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02181969
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 76
    Electronic Resource
    Electronic Resource
    Gains and losses in soil nutrients associated with harvesting and burning eucalypt rainforest (1983)
    Springer
    Plant and soil 74 (1983), S. 437-450 
    Details
    ISSN: 1573-5036
    Keywords: Burning controlled ; Calcium ; Carbon ; CEC ; Eucalyptus ; Magnesium ; Nitrogen ; N. mineralisation ; Potassium ; Rainforest
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In mixed eucalypt/rainforest in southern Tasmania, samples of surface soil 0 to 2 cm, 2 to 5 cm, and 5 to 10 cm were taken from a clear-felled coupe before and after burning in 1982, from a similar coupe after burning in 1979, and from an uncut area adjacent to each coupe. Factors compared were bulk density; total organic C, N, P, Ca, Mg, and K; pH; exchangeable Ca, Mg, and K; cation exchange capacity; extractable P; and N-mineralisation rates. The effect of burning was found to be restricted mainly to the upper 2 cm of soil. The combustion of organic matter caused losses of 7360 kg organic C and 211 kg N/ha; 348 kg Ca and 282 kg Mg and 151 kg K/ha were added to the soil in ash. Burning caused significant increases in pH, exchangeable Ca, Mg, and K, and in extractable P; cation exchange capacity was reduced. In the 6 months after burning only K was leached from the upper 2 cm of soil. Equilibrium levels of NH4−N increased initially after the fire, but between 6 and 18 months, equilibrium levels and rate of production of NH4−N during anaerobic incubation in soil of burned coupes differed little from that in adjacent uncut forest. Rates of production of NO3−N during aerobic incubation were very low throughout the period of study. It is concluded that for soils developed on dolerite in mixed eucalypt/rainforest, a single regeneration burn probably improves the nutritional status of the soil. Nutrients lost from the area as particulate ash are in quantities that will probably be replaced in rainfall in 15 to 20 years.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02181361
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 77
    Electronic Resource
    Electronic Resource
    The pineal organ of Raja clavata: Opsin immunoreactivity and ultrastructure (1983)
    Springer
    Cell & tissue research 228 (1983), S. 139-148 
    Details
    ISSN: 1432-0878
    Keywords: Pineal organ ; Pineal photoreceptors ; Opsin immunoreactivity ; Electron microscopy ; Elasmobranch (Raja clavata)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The pineal organ of Raja clavata was studied by light and electron microscopy, including the immunocytochemical antiopsin reaction. The pineal organ of the ray consists of three portions: (i) a large proximal pineal, (ii) a long tube-like connecting stalk, and (iii) a short distal terminal enlargement. This latter end-vesicle lies in the deep connective tissue layers of the braincase. All portions of the pineal are composed of pinealocytes, intrinsic neurons, ependymal/glial cells, and bundles of nerve fibers embedded in thin neuropil formations. The inner segments of the pinealocytes protrude into the lumen in all parts of the organ and usually contain basal bodies and numerous mitochondria. Often, two outer segments were found to arise from the basal bodies of a single inner segment. By means of light-microscopic immunocytochemistry the outer segments showed a strong antiopsin reaction. The axons of the pinealocytes form ribbon-containing synapses on dendritelike profiles, which appear to belong to the intrinsic pineal neurons. There are other axo-dendritic synapses established by presynaptic terminals lacking ribbons and containing granular and synaptic vesicles. Pineal neurons may contain granular vesicles approximately 60–100 nm in diameter; their processes contribute to the bundles of unmyelinated axons. The fine structural organization of the pineal organ and the opsin immunoreactivity of the outer segments of the pinealocytes indicate a photoreceptive capacity of the organ. The double outer segments represent a peculiar multiplication of the photoreceptor structures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00206272
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 78
    Electronic Resource
    Electronic Resource
    The effect of decentralisation or chronic hypogastric nerve stimulation in vivo on the innervation and responses of the guinea-pig vas deferens (1983)
    Springer
    Cell & tissue research 232 (1983), S. 265-279 
    Details
    ISSN: 1432-0878
    Keywords: Innervation ; Decentralisation ; Hypogastric nerve ; Pharmacology ; Electron microscopy ; Vas deferens ; Guinea-pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The physiological, pharmacological and morphological characteristics of guinea-pig vas deferens supplied by hypogastric nerves rendered inactive by decentralisation were compared with those of vas deferens in which the nerve supply had been chronically stimulated for 3–9 days using implanted electrodes. No change was seen in decentralised preparations prior to 7 days, but from 8–15 days, increased sensitivity to application of noradrenaline in vitro was observed, which was shown to be related to reduced transmitter uptake by nerve terminals as well as to an increase in postjunctional sensitivity; there was also increased fatigability 7–14 days following decentralisation. Continuous stimulation of hypogastric nerves at 2 Hz for 4–8 h daily for 4–8 days resulted in enhanced transmitter uptake and reduced responses to noradrenaline; this was associated with a slight increase in noradrenaline content and a faster adrenergic neuromuscular response with a shorter latency. No appreciable changes in nerve or muscle structure studied by electron microscopy were observed following decentralisation, but there was an increase of between 12.5 and 29.6% in the number of close (〈 100 nm) neuromuscular junctions following chronic stimulation for 8 days.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00213786
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 79
    Electronic Resource
    Electronic Resource
    Development ot the granule population in heterophil granulocytes from rat bone marrow (1983)
    Springer
    Cell & tissue research 228 (1983), S. 433-449 
    Details
    ISSN: 1432-0878
    Keywords: Bone marrow (rat) ; Heterophil granulocyte ; Granules ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The development of the heterophil granulocyte in the bone marrow of the rat is described, and an electron-microscopical analysis of the changes in the cytoplasm as well as in the granule population in several stages of maturation is reported. Three types of granule originate in consecutive stages of heterophil maturation. Granules with an internal fine structure (nucleated granules) are the first to be formed, i.e., in early promyelocytes; azurophil granules are formed in late promyelocytes; and specific granules appear in myelocytes. Quantitative analysis showed that the granule population in mature cells, i.e., about 160 granules per electron micrograph, is composed of roughly 14% nucleated granules, 10% azurophil granules, and 76% specific granules. Three cell stages were observed in mitosis: the early promyelocyte, the late promyelocyte, and the myelocyte. Granule counts in non-dividing cells confirmed the occurrence of mitosis in the late promyelocyte and myelocyte.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00211466
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 80
    Electronic Resource
    Electronic Resource
    Sarcoplasmic reticulum and intermediate filament organization in cultured neonatal cardiac muscle cells (1983)
    Springer
    Cell & tissue research 228 (1983), S. 489-496 
    Details
    ISSN: 1432-0878
    Keywords: Heart ; Tissue culture ; Electron microscopy ; Myocyte
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Cardiac muscle cells from 3-day-old rat neonates were cultured for periods of 2 to 56 days. In order to facilitate ultrastructural studies on the organization of the sarcoplasmic reticulum, the cells were prepared for transmission electron microscopy according to a regimen including postfixation in reduced osmium ferrocyanide. The nonjunctional sarcoplasmic reticulum (NJSR) was organized as a loose, fenestrated sleeve around the exterior of bundles of myofilaments and was particularly prominent at the level of the Z line. The only recognizable junctional elements of the sarcoplasmic reticulum were in a peripheral location. Reduced osmium ferrocyanide was also useful in distinguishing intermediate (10nm) filaments, since it understained Z substance, which often obscured these structures. Intermediate filaments were arranged both at the Z line and the intercalated disc, in parallel strands, approximately at right angles to the myofilaments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00211470
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 81
    Electronic Resource
    Electronic Resource
    Ultrastructural characteristics of immunolabelled, corticotropin releasing factor (CRF)-synthesizing neurons in the rat brain (1983)
    Springer
    Cell & tissue research 229 (1983), S. 191-196 
    Details
    ISSN: 1432-0878
    Keywords: CRF ; immunolabelling ; Paraventricular nucleus ; Median eminence ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The corticotropin releasing factor (CRF)-synthesizing perikarya and neural processes were detected at ultrastructural level in the hypothalamic paraventricular nucleus and in the median eminence of control and colchicine-pretreated rats. The unlabelled antibody peroxidase-antiperoxidase complex (PAP) immunohistochemical method was used in a pre-embedding manner, on thick, non-frozen sections. In CRF-perikarya, neurosecretory granules (80–120 nm in diameter), free ribosomes, and the rough endoplasmic reticulum were labelled. Unlabelled axon terminals formed asymmetric synapses on CRF-containing perikarya and dendrites. Immunolabelled axons terminated in the palisadic zone of the median eminence.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00217891
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 82
    Electronic Resource
    Electronic Resource
    Cytochemical localisation of calcium binding sites in adrenal chromaffin cells and their relation to secretion (1983)
    Springer
    Cell & tissue research 229 (1983), S. 207-217 
    Details
    ISSN: 1432-0878
    Keywords: Exocytosis ; Secretion ; Calcium ; Chromaffin cells ; Adrenal medulla
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructural localisation of calcium in the chromaffin cells of the adrenal medulla was investigated using the pyroantimonate technique. The electron-dense precipitate resulting from processing in the presence of pyroantimonate was removed by treatment of sections with 2 mM EGTA suggesting that the pyroantimonate technique was localising calcium since this chelator shows a 1000∶1 preference for Ca2+ over Mg2+. Using dissociated cells from the bovine adrenal medulla, calcium was localised in control cells and in cells stimulated with 1 mM carbamylcholine for 1, 10 and 30 min. Stimulation resulted in an increase in plasma membrane-associated calcium within 1 min. Much of this calcium was localised at sites of granule-plasma membrane interaction and was also seen at sites of coated-vesicle formation at longer periods of stimulation. Membrane-bounded vacuoles, appearing in cells stimulated for 10 or 30 min, also showed associated electron-dense precipitate. The results obtained are consistent with a role for the calcium ion as a mediator in exocytosis at the stage of granule-plasma membrane fusion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00217893
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 83
    Electronic Resource
    Electronic Resource
    Synaptic organisation of the pelvic ganglion in the guinea-pig (1983)
    Springer
    Cell & tissue research 232 (1983), S. 379-397 
    Details
    ISSN: 1432-0878
    Keywords: Electron microscopy ; Pelvic ganglia ; Autonomic nervous system ; Synapses ; Neurones ; Guinea-pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A semi-quantitative electron-microscopic study of neuronal cell bodies, nerve profiles and synapses in the anterior pelvic ganglia of the guinea-pig has been carried out following in vivo labelling of adrenergic nerve endings with 5-hydroxydopamine. Ganglion cells of three main types have been distinguished: 1) the majority (about 70%) not containing granular vesicles, probably cholinergic elements; 2) those containing large granular vesicles of uniform size (80–110 nm), with granules of medium density and prominent halos; and 3) those containing vesicles of variable size (60–150 nm), with very dense eccentrically placed granular cores. Some non-neuronal ‘granule-containing’ cells were present, mainly near small blood vessels. Some 95% of the total axon profiles within the ganglia were cholinergic, the remaining 5% were adrenergic. However, 99% of synapses (i.e. axons within 50 nm of nerve cell membrane with pre-and post-synaptic specialisations) were cholinergic, and 1 % were adrenergic. Only three examples of nerve cell bodies exhibiting both cholinergic and adrenergic synapses were observed. Unlike the para-and prevertebral ganglia, the pelvic ganglia contained large numbers of axo-somatic synapses. As many as 20% of the nucleated neuronal cell profiles displayed two distinct nuclei.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00213794
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 84
    Electronic Resource
    Electronic Resource
    Decentralisation of neurones in the pelvic ganglion of the guinea-pig: Reinnervation by adrenergic nerves (1983)
    Springer
    Cell & tissue research 232 (1983), S. 399-411 
    Details
    ISSN: 1432-0878
    Keywords: Pelvic ganglion ; Reinnervation ; Decentralisation ; Autonomie nervous system ; Electron microscopy ; Guinea-pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An electron-microscopic study has been made of adrenergic and cholinergic nerve fibres and synapses in the pelvic ganglion of the guinea-pig at intervals of up to 60 days following section of the hypogastric and pelvic nerves. Transection of the hypogastric nerves led to degeneration of 80–90% of the cholinergic nerve profiles and synapses in the ganglion. The small number of adrenergic nerves and synapses did not change, but 30–60 days after section, this number increased 8–10 times. Transection of the pelvic nerves led to degeneration of about 15% of the cholinergic nerve terminals, but no change in adrenergic terminals. After transection of both hypogastric and pelvic nerves, only about 1% of cholinergic nerves survived, but after 30–60 days, the number of adrenergic nerves increased 8–10 times. It is concluded that following cholinergic nerve degeneration in the ganglion, adrenergic nerves, probably originating as collateral sprouts from postganglionic neurones and granule-containing cells, can replace them to some extent.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00213795
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 85
    Electronic Resource
    Electronic Resource
    Ultrastructure, function and composition of smooth muscle (1983)
    Springer
    Annals of biomedical engineering 11 (1983), S. 579-588 
    Details
    ISSN: 1573-9686
    Keywords: Smooth muscle ; Electron probe analysis ; Calcium ; Myosin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract Filamentous myosin is present in both relaxed (myosin light chains unphosphorylated) and contracted (light chains phosphorylated) vascular smooth muscle. The organization of myosin and actin filaments and the insertion of the latter on cytoplasmic and plasma membrane bound dense bodies is consistent with a mini sarcomere-like organization and a sliding filament mechanism of contraction in smooth muscle. Mitochondria are high capacity, low affinity Ca stores in smooth muscle. They do not play a role in the regulation of cytoplasmic Ca2+ at physiological levels. The localization and Ca content of the junctional sarcoplasmatic reticulum (SR) is consistent with this organelle being the major intracellular source of activator Ca released by excitatory transmitters. Repeated contractions in the absence of extracellular Ca2+ (thought to represent recycling of intracellular activator Ca2+) can be demonstrated if the excitatory agent is not allowed to remain in contact with the smooth muscle throughout relaxation; the demonstration of “recycling” is facilitated if the efflux of cellular Ca2+ is blocked. The rise in total cytoplasmic calcium measured with electron probe analysis during a maintained (30 min) contracture in rabbit portal-anterior mesenteric vein smooth muscle (∼0.9 mmol/kg dry cytoplasm) is greater than the amount of Ca that could be bound to calmodulin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02364087
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 86
    Electronic Resource
    Electronic Resource
    Production and formation of the basement membrane in embryonic tissues of the mouse (1983)
    Springer
    Cell & tissue research 228 (1983), S. 85-98 
    Details
    ISSN: 1432-0878
    Keywords: Basement-membrane production ; Mouse embryos ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Mouse embryos (strain NMRI) of days 9 + 2h, 9 + 12h, 10 + 2h, 10 + 12h, 11 + 2h, 12 + 2h, 13 + 2h, and 14 + 2h were fixed (i) in 3% glutaraldehyde +3% paraformaldehyde, (ii) in 1% glutaraldehyde +1% tannic acid, or (iii) in 1% glutaraldehyde +1.5% ruthenium red. The electronmicroscopic picture of the basement membrane (BM) changed depending on the fixative used. Addition of tannic acid led to a higher staining intensity of glycoproteins, whereas after ruthenium red proteoglycans were more heavily stained. The BM around the neural tube and around the epithelial tubules in the lung anlage were investigated electron microscopically. After fusion, the BM in the dorsal regions of the neural tube is missing; on days 9–10 it is, however, reformed. Between days 11 and 13 wide gaps in the BM of the lung anlage occur at the growth buds of the epithelial tubes, which are bridged on late day 13. In the basal parts of these two epithelial types membrane-bordered granules of different density occur singly or in groups. It is postulated that these structures contain BM-material and represent secretion granules. After secretion, BM-material is first bound to the cell membrane. This process is important for the initiation of the formation of the BM. Further growth, however, proceeds via lateral aggregation (self-assembly). Thus, intercellular gaps are bridged independent of the cell membrane. The process of lateral aggregation may also explain deviations from the normal course of the BM.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00206267
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 87
    Electronic Resource
    Electronic Resource
    Quinacrine-induced degeneration of non-adrenergic, non-cholinergic autonomic nerves in the rat anococcygeus muscle (1983)
    Springer
    Cell & tissue research 230 (1983), S. 639-648 
    Details
    ISSN: 1432-0878
    Keywords: Non-adrenergic, non-cholinergic autonomic nerves ; Quinacrine ; Fluorescence microscopy ; Electron microscopy ; Anococcygeus muscle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The morphological changes induced in the autonomic nerves of the rat anococcygeus muscle after the injection of quinacrine (QC, 100 or 200 mg/kg) were examined by electron microscopy in order to clarify the nature of QC-binding nerves seen at the fluorescence-microscopic level. A correspondence between granular QC fluorescence and many lysosomal dense bodies is observed both in the cytoplasm of muscle cells and in non-adrenergic, non-cholinergic (NANC) axons during the first few days following injection. A number of brilliantly fluorescent fibres is observed 1 week after injection. At the ultrastructural level, these fibres seem to correlate with NANC axons which are crowded with many dense bodies and large granular vesicles. Notably, some lysosomal dense bodies contain many large granular vesicles. The effects of QC injection on the ultrastructure of adrenergic axons have also been observed, but are not so marked as in the NANC axons. The administration of QC did not cause complete degeneration of the NANC nerves, though degenerating axons were sometimes observed. The present data indicate that most, if not all, QC-binding nerves observed at the fluorescence-microscopic level correspond to NANC nerves at the electron-microscopic level. Furthermore, NANC axons appear to contain a considerable amount of ATP concentrated in the large granular vesicles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00216207
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 88
    Electronic Resource
    Electronic Resource
    Calcium dynamics, exocytosis, and membrane turnover in the ovulation hormone-releasing caudo-dorsal cells of Lymnaea stagnalis (1983)
    Springer
    Cell & tissue research 233 (1983), S. 143-159 
    Details
    ISSN: 1432-0878
    Keywords: Calcium ; Exocytotic hormone release ; Membrane resorption ; Mitochondria ; Lymnaea stagnalis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The axon terminals of the neuroendocrine caudo-dorsal cells (CDC) of the freshwater snail Lymnaea stagnalis release an ovulationstimulating hormone by exocytosis in a calcium-dependent way. Ultrastructural studies of the terminals, involving the K-pyroantimonate method for the demonstration of calcium and control tests with EGTA, show that calcium occurs in mitochondria and in various types of vesicular structure. Quantitative investigations indicate that mitochondria accumulate calcium during a short period of high neurohormone-release activity (“active state”; ca. 45 min) and release it again into the axoplasm some hours later, during a period of low secretory activity (“resting state”). Probably, in this way mitochondria play an important role in the buffering of the axoplasmic calcium concentration during high hormone-release activity. HRP-incorporation studies strongly suggest that the calcium-containing vesicular structures constitute a mechanism of membrane sequestration by which the CDC axon terminals resorb, transform, and release parts of the axolemma after exocytotic hormone release. The results furthermore indicate that this mechanism also may be involved in the control of the calcium concentration of the axoplasm, by taking up calcium from the axoplasm and releasing it into the extracellular space.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00222239
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 89
    Electronic Resource
    Electronic Resource
    A comparative study of primary and secondary granules in monocytopoiesis and myelopoiesis of mouse bone marrow (1983)
    Springer
    Cell & tissue research 228 (1983), S. 107-115 
    Details
    ISSN: 1432-0878
    Keywords: Bone marrow (mouse) ; Monocytes ; Neutrophil granulocytes ; Granules ; Electron microscopy ; Peroxidase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The differentiation and maturation of monocytes and neutrophil granulocytes were studied in bone marrow of normal mice by electron microscopy and cytochemical assessment of peroxidatic activity. The granule populations of the mature cells of bone marrow were identified and investigated to obtain a basis for the analysis of the earlier stages of maturation. Mature monocytes and neutrophils showed primary and secondary granules, and mature neutrophils had more of both kinds. The size, shape, and number of primary granules proved to offer the most reliable criteria for distinguishing promonocytes and promyelocytes. The primary granules of monocytes were smaller than those of mature neutrophils and were either spherical (smallest diameter 50–200 nm) or elongate (100×400 nm). Both granules had a homogeneous matrix. The granules of the granulocytes were either spherical (smallest diameter 200–300 nm) or elongate (150–200×300–500 nm), and some of them had a crystalline inclusion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00206269
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 90
    Electronic Resource
    Electronic Resource
    Changes in the organization and ultrastructure of smooth muscle cells in the stomach of the gastric brooding frog, Rheobatrachus silus, during brooding (1983)
    Springer
    Cell & tissue research 231 (1983), S. 451-456 
    Details
    ISSN: 1432-0878
    Keywords: Smooth muscle ; Anura ; Stomach ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The young of the aquatic Australian frog, Rheobatrachus silus (Leptodactylidae) develop from eggs to juvenile frogs in the mother's stomach. During brooding the stomach expands greatly and becomes very thin walled. Transmission electron microscopy showed that the distension of the stomach was accompanied by a severe disruption of the smooth muscle layers. Many of the smooth muscle cells seemed to be highly contracted and resembled smooth muscle cells contracted in the absence of an intact connective tissue matrix. Eight days after the birth of the juveniles through the mouth of the female, the stomach muscle cells had returned to a normal appearance. It is suggested that during gastric incubation of the young, smooth muscle cells become at least partially dissociated from their surrounding connective tissue matrix, allowing maximal distension of the stomach wall.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00222194
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 91
    Electronic Resource
    Electronic Resource
    Genetic dissection of the anterior optic tract of Drosophila melanogaster (1983)
    Springer
    Cell & tissue research 231 (1983), S. 551-563 
    Details
    ISSN: 1432-0878
    Keywords: Visual mutants ; Anterior optic tract ; Independent gene actions ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Electron microscopy shows that in wild-type Drosophila melanogaster the anterior optic tract (AOT) is formed by about 1260 fibers in males and slightly fewer in females. Golgi staining suggests that most AOT fibers connect the lobula with different regions of the central brain. In the sine oculis (so) and small optic lobes (sol) mutants the number of axons is drastically reduced, by 58% in sol and by 35% in so. In the double mutant sol:so there is a loss of up to 83% of the fibers in the AOT. Approximately half of the remaining 220 fibers form a well defined subbundle of very thin axons which is identifiable in wild type as well as in both single mutants. The fibers of this subbundle neither originate nor terminate in the visual ganglia: instead, they connect two different central brain regions. It is concluded that the combined action of the sol and so mutations abolishes more than 90% of the fibers of visual origin or destination in the AOT. Quantitative analysis of electron micrographs shows that the so and sol mutations act independently on nearly exclusive subsets of axons in the AOT.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00218113
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 92
    Electronic Resource
    Electronic Resource
    Preliminary observations of satellite cells in undamaged fibres of the rat soleus muscle assaulted by a snake-venom toxin (1983)
    Springer
    Cell & tissue research 230 (1983), S. 671-776 
    Details
    ISSN: 1432-0878
    Keywords: Satellite cells ; Skeletal muscle ; Snake-venom toxin ; Muscle regeneration ; Electron microscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Satellite cells were studied in the undamaged part of the rat soleus muscle rendered partially necrotic by a subcutaneous injection of notexin, the myotoxic toxin purified from the venom of the Australian snake Notechis scutatus scutatus. Nuclei of satellite cells were twice as numerous as in the controls, with a decreasing gradient in the number of satellite cells with distance from the necrotic area. The cells were in an activated state with an increased cytoplasmic volume and prominent organelles. Occasionally, mitosis of some satellite cells was observed. Between the satellite cell and the muscle fibre, an unusually wide space was frequently seen, within which a “new” basal lamina was often visible. It is suggested that the role of the satellite cells of undamaged muscle fibres in the regeneration of necrotic muscle is worthy of more detailed investigation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00216210
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 93
    Electronic Resource
    Electronic Resource
    Influence of short photoperiods on the ultrastructure of hamster Harderian glands (1983)
    Springer
    Cell & tissue research 233 (1983), S. 209-213 
    Details
    ISSN: 1432-0878
    Keywords: Hamsters ; Harderian glands ; Short photoperiod ; Sexual dimorphism ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A sexual dimorphism of the hamster Harderian gland at the ultrastructural level, has been reported. Castration of males and the administration of testosterone to females are known to alter the male type gland to the female type and vice versa. In this paper we present data that exposure to a short photoperiod (1L:23D) can induce similar structural alterations between the 4th and 10th week of exposure. Changes in the male included reduction in the number of tubular clusters and large vacuoles, while in the female the number of membrane formations decreased with an accompanying appearance of tubular clusters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00222244
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 94
    Electronic Resource
    Electronic Resource
    Heat of fusion and lamellar structure of polyethylene single crystal mats (1982)
    Springer
    Colloid & polymer science 260 (1982), S. 564-569 
    Details
    ISSN: 1435-1536
    Keywords: lin. Polyethylene ; Single crystals ; Heat of Fusion ; DSC ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Recently published results for solution crystallized PE single crystals have shown, that the experimental heat of fusionΔH * is higher, if the solvent is exchanged to silicon oil (oil suspension samples) as compared with dried mats. This has been interpreted by the collapse of the original hollow pyramids during drying, inducing lateral defects within the lamellae. The present investigation does not confirm this unexpected result.ΔH * of dried mats (T c 66 to 91 °C) and of the corresponding oil suspension samples agree within the rather small limits of experimental error. The crystallinities as derived fromΔH *, density or WAXS are in excellent agreement. SEM micrographs of cold fractured dried mats show their spongy macromorphology, but TEM micrographs of stained ultra-thin sections reveal the lamellar morphology of the walls, consisting of curved lamellae and stacked hollow pyramides. If a dried mat is sintered at room temperature, a dense transparent film is obtained with a rather regular stacked morphology of large flat lamellae.ΔH * of these films agrees with that of the original mat.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01422587
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 95
    Electronic Resource
    Electronic Resource
    Equilibrium dialysis and ultrafiltration studies of calcium and phosphate binding by human salivary proteins. Implications for salivary supersaturation with respect to calcium phosphate salts (1982)
    Springer
    Calcified tissue international 34 (1982), S. 531-538 
    Details
    ISSN: 1432-0827
    Keywords: Saliva ; Calcium ; Phosphate ; Ion-binding ; Supersaturation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Previous ultrafiltration studies indicated that up to one-half of the calcium and two-thirds of the phosphate in human salivary secretions may be bound by salivary proteins. Since this binding is an important variable in determining the extent of salivary supersaturation with respect to calcium phosphate salts, and since the amount of binding reported is surprisingly large, calcium and phosphate ion-binding by salivary macromolecules has been reexamined. From experiments using equilibrium dialysis, it was found that (1) the fraction of salivary calcium involved in macromolecular complexes ranges from a few percent for unstimulated secretions, to no more than about 10% for stimulated glandular salivas, and (2) salivary proteins do not bind phosphate ions to any significant extent. These findings, and experiments using an improved ultrafiltration membrane, indicate that the earlier results were artifacts of the ultrafiltration technique. Fractionation of salivary proteins, followed by equilibrium dialysis measurements, showed that the anionic proline-rich proteins and a basic proline-rich glycoprotein are responsible for most of the calcium binding now observed. The finding that macromolecular complexes of salivary calcium and phosphate have been overestimated in the past, leads to the conclusion that salivary calcium and phosphate ion activities in stimulated salivary secretions may be up to 50 to 100% higher than previously thought. Revised values were therefore used to recalculate the degree of salivary supersaturation with respect to calcium phosphate salts. The results indicate that stimulated salivary secretions are supersaturated with respect to dicalcium phosphate dihydrate; this is a substantially greater degree of supersaturation than previously reported.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02411299
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 96
    Electronic Resource
    Electronic Resource
    Ultrastructural evidence for inhibition of chitin synthesis by nikkomycin (1982)
    Springer
    Development genes and evolution 191 (1982), S. 205-207 
    Details
    ISSN: 1432-041X
    Keywords: Chitin inhibition ; Nikkomycin ; Cuticle ; Electron microscopy ; Epilachna varivestis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The nucleoside antibiotic nikkomycin has proved to be an effective inhibitor of chitin synthesis in the Mexican bean beetleEpilachna varivestis. Ultrastructural investigations show defects in the procuticular area after nikkomycin application which suggest the complete absence of chitin. A cuticle like this is inflexible and too brittle to satisfy its normal function as an exoskeleton. The individuals are not able to free themselves from the exuvia and finally die. Therefore nikkomycin seems to be a potential insecticide with high specifity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848337
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 97
    Electronic Resource
    Electronic Resource
    Effect of 1,25-dihydroxyvitamin D3 on osteopenia induced by prednisolone in adult rats (1982)
    Springer
    Calcified tissue international 34 (1982), S. 253-257 
    Details
    ISSN: 1432-0827
    Keywords: Prednisolone ; Calcium ; Bone ; Corticoid osteopenia ; Vitamin D metabolites
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Adult male rats were fed a diet containing 0.15% calcium, 0.3% phosphorus, and either 100, 50, or 20 mg of prednisolone per kg of diet. All these levels of prednisolone led to osteopenia, decreased intestinal absorption of calcium, slightly lower serum calcium and phosphorus, and a decreased level of serum 1,25-dihydroxyvitamin D3. Exogenous parenteral 1,25-dihydroxyvitamin D3 corrected steroid-induced changes in serum calcium and phosphorus, but could not completely correct the low intestinal calcium transport; nor did it prevent the development of osteopenia. The prednisolone-induced osteopenia seems at least in part to be caused by impaired intestinal calcium transport. The impaired calcium transport may be the result of low levels of 1,25-dihydroxyvitamin D3 and a direct effect of presnisolone on the intestine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02411246
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 98
    Electronic Resource
    Electronic Resource
    Effect of phosphate on phosphatidylserine-mediated calcium transport (1982)
    Springer
    Calcified tissue international 34 (1982), S. 43-48 
    Details
    ISSN: 1432-0827
    Keywords: Calcium ; Phosphate ; Phosphatidylserine ; Transport ; Mineralization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Experiments were performed to study the effect of inorganic phosphate (Pi) on phosphatidylserine-mediated Ca2+ transport utilizing two- and three-compartment lipid-aqueous phase model systems. When the three-compartment model was used, the rate of Ca2+ transport from an aqueous donor compartment to an aqueous receiver compartment, separated by a nonaqueous phospholipid phase, was determined. This experiment showed that the rate of Ca2+ transport was proportional to the phosphatidylserine concentration and the pH. Pi modulated the rate of Ca2+ transport; even when the Pi concentration of the donor aqueous phase was low, there was a marked enhancement of transport. To determine whether the Pi-mediated rise in the Ca2+ transport rate was due to an increase in the uptake of Ca2+ into the lipid phase, or to an increase in the ability of the lipid phase to release Ca2+, a two-compartment model was used. It was found that the ability of the phosphatidylserine phase to take up Ca2+ increased as the Pi concentration of the aqueous donor phase was raised. With the increase in Ca2+ uptake there was a concomitant elevation in the rate of Ca2+ transport into an aqueous receiver phase. However, Pi did not stimulate Ca2+ release from the phosphatide. Thus it was concluded that Pi enhanced the interaction between Ca2+ and phosphatidylserine, possibly by forming a Ca-phospholipid-Pi complex. Once this interaction had taken place, Ca2+ release into the aqueous receiver compartment was independent of the Pi concentration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02411207
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 99
    Electronic Resource
    Electronic Resource
    Changes in plasma bone GLA protein during treatment of bone disease (1982)
    Springer
    Calcified tissue international 34 (1982), S. 121-124 
    Details
    ISSN: 1432-0827
    Keywords: Bone ; Calcium ; Metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Bone Gla protein (BGP) was measured in the plasma by radioimmunoassay (RIA) during treatment of 59 patients with bone diseases including Paget's disease (N=9), primary hyperparathyroidism (N=25), chronic renal failure (N=20), and cancer involving bone (N=5). Plasma BGP was increased above normal in all patients. BGP decreased in the patients with Paget's disease following the acute and chronic administration of salmon calcitonin. Plasma BGP was higher in women then in men with primary hyperparathyroidism. Following parathyroidectomy, BGP decreased in both sexes but the decrease was significant in women only. Plasma BGP was increased in patients with renal osteodystrophy and did not change after hemodialysis. In the patients with bone cancer, plasma BGP decreased during treatment of the attendant hypercalcemia with salmon calcitonin. Although plasma BGP and serum alkaline phosphatase (AP) levels were generally correlated in these studies, there were examples of dissociation between the two. The measurement of plasma BGP appears to provide a specific index of bone metabolism that may in some circumstances be more sensitive than serum alkaline phosphatase measurement. However, further studies are necessary to establish the clinical value of plasma BGP measurement by RIA in the management of patients with bone diseases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02411221
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 100
    Electronic Resource
    Electronic Resource
    On the role of calcium in chemotaxis and oscillations of dictyostelium cells (1982)
    Springer
    European biophysics journal 9 (1982), S. 131-136 
    Details
    ISSN: 1432-1017
    Keywords: Chemotaxis ; Calcium ; Oscillation ; Dictyostelium ; Ionophore
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract Migration of differentiated cells to a capillary containing cyclic AMP was enhanced in the presence of 1 mM CaCl2 and was virtually absent in the presence of 1 mM EGTA. Furthermore, the cells contracted and extended pseudopods to a capillary filled with the calcium ionophore A 23187. At short distances, migration to the tip of the capillary was observed. The ionophore also induced transient decreases of the optical density of suspended cells indicating changes of cell shape. These findings support the hypothesis that cyclic AMP-binding to cell surface receptors causes a local influx of calcium ions. These in turn lead to an increase of the cytosolic calcium concentration and subsequently to an activation of cell migration. Perturbing pulses of the ionophore induced permanent phase shifts of free-running light scattering oscillations. This result indicates that cytosolic calcium is an intrinsic component of the oscillatory system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00539112
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...