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  • Wheat  (108)
  • Calcium  (98)
  • Springer  (203)
  • American Association for the Advancement of Science
  • 2010-2014
  • 2005-2009
  • 1980-1984  (203)
  • 1925-1929
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  • 1
    Electronic Resource
    Electronic Resource
    Über Erdalkalimetalloxogallate. VIII Synthese und Aufbau eines neuen Calciumoxogallats: Ca3Ga4O9 (1981)
    Springer
    Monatshefte für Chemie 112 (1981), S. 149-156 
    Details
    ISSN: 1434-4475
    Keywords: Calcium ; Gallium ; Oxygen ; Single Crystal ; X-Ray
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The hitherto unknown compound Ca3Ga4O9 was prepared and investigated by X-ray single crystal methods. Ca3Ga4O9 has orthorhombic symmetry:a=1435.8;b=1682.5;c=532.1 pm; space group C 2v 11 −Cmm2,Z=6. The tetrahedra network (circles of 4 and 5 GaO4-tetrahedra) and the surrounding of Ca2+ are described and discussed with respect to other oxogallates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00911081
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  • 2
    Electronic Resource
    Electronic Resource
    Calcium-mediated enhancement of the cyclic AMP response in cultured bone cells (1981)
    Springer
    Calcified tissue international 33 (1981), S. 409-416 
    Details
    ISSN: 1432-0827
    Keywords: Bone Cells ; Cyclic AMP ; Calcium ; Parathyroid hormone ; Prostaglandin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary We have examined the influence of extracellular Ca2+ on cyclic AMP metabolism in an osteoblast-enriched population of bone cells isolated from the calvaria of rat fetuses. The cyclic AMP1 response to stimulators of cyclic AMP formation (PTH and PGE2), but not basal cyclic AMP levels, increased progressively as the extracellular Ca2+ concentration was raised from 0.2 to 4.0 mM. The response to changes in extracellular Ca2+ were rapid (within 3.5 min), and the level of responsivity that characterized each Ca2+ concentration persisted for at least 6 h when the Ca2+ concentration was kept constant. The effect of Ca2+ spanned the entire time course of PTH action, was not accompanied by altered excretion of cyclic AMP from the cells, and was evident at low as well as at high hormone concentrations. Ca2+ augmented the action of PTH in the presence as well as in the absence of cyclic AMP phosphodiesterase inhibitors, and failed to decrease cyclic AMP phosphodiesterase activity in the short term. Mn2+ and, to a smaller degree, Ba2+ substituted for Ca2+ in promoting the cyclic AMP response to PTH. Verapamil, an inhibitor of Ca2+ penetration, blunted the Ca2+-mediated increments in the cyclic AMP response, and the divalent cation ionophore A23187 enhanced these increments. These results indicate that Ca2+ and other cations are positive effectors of the stimulated cyclic AMP response in isolated bone cells. Accumulation into an as yet unknown cellular compartment may be required for the cation effect. The data are most consistent with enhancement of adenylate cyclase reactivity as the mode of cation action.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02409464
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  • 3
    Electronic Resource
    Electronic Resource
    In vitro effects of vitamin D3 metabolites on rat calvaria cAMP content (1980)
    Springer
    Calcified tissue international 30 (1980), S. 209-216 
    Details
    ISSN: 1432-0827
    Keywords: Calvarium ; cAMP ; Vitamin D3 metabolites ; Calcium ; Parathyroid hormone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Results from in vitro works suggest that 1,25- and 24,25-dihydroxyvitamin D3 (1,25-(OH)2D3 and 24,25-(OH)2D3) act on bone via different mechanisms. The present investigation was performed to study the effect of these two metabolites and of their precursor 25-hyxdroxyvitamin D3 (25-(OH)D3) on bone cAMP content in vitro. Rats' paired half calvaria were incubated under sterile conditions with one vitamin D3 derivative (10−13 to 10−9 M) or with ethanol (0.005 ml for 15 min to 24 h in 1 ml medium containing 0, 0.2, 1, 2, or 3 mM calcium. In some experiments: (a) cycloheximide (10−5M) was added simultaneously with the vitamin D3 metabolites; (b) 1–84 bPTH (5 × 10−8 M) was added for 5 or 15 min at the end of the 24 h incubation. Calvaria were immersed in 1 ml TCA 5% 4°C and homogenized. The cAMP was extracted with diethylether and measured by a competitive protein binding assay. Results bring further evidence for a particular effect of low doses of 24,25-(OH)2D3 (10−9 to 10−12M) and of 25-(OH)D3 (10−9 to 10−11M) on bone, different from that of 1,25-(OH)2D3: cAMP content was higher in 24,25-(OH)2D3- or 25-(OH)D3-treated and lower in 1,25-(OH)2D3-treated calvaria than in ethanol-treated ones with 1 mM calcium. The 1,25-(OH)2D3 effect persisted in calcium-free medium whereas 25-(OH)D3 and 24,25-(OH)2D3 effects could not be observed with 0 mM nor with 3 mM calcium. The required duration of the preincubation (over 1 h) as well as the inhibitory action of cycloheximide may suggest an involvement of protein synthesis in the vitamin D3 metabolites effects. Neither 1,25-(OH)2D3 nor 24,25-(OH)2D3 affected the PTH-induced increase in bone cAMP content.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02408630
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  • 4
    Electronic Resource
    Electronic Resource
    Effects of magnesium ion on parathyroid hormone secretion in vitro (1980)
    Springer
    Calcified tissue international 32 (1980), S. 201-206 
    Details
    ISSN: 1432-0827
    Keywords: Magnesium ; Parathyroid hormone ; Secretion ; In vitro ; Calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary In a well-defined in vitro perifusion system, the effects of extracellular magnesium concentration (Mg) on parathyroid hormone (PTH) secretion by bovine parathyroid tissue were examined. At Mg less than 0.8 mM, the ability of the glands to secrete hormone maximally in response to low calcium (Ca) stimulation was progressively impaired. Low Mg also impaired the ability of isoproterenol, dibutyryl cyclic AMP and theophylline to stimulate hormone release. The defect in hormone release at low Mg observed in vitro was analogous to the well-documented inhibition of secretion observed in vivo. Increases in Mg from 0 to 0.8 mM rapidly repaired the defect in hormone secretion. At Mg above 1.0 mM there was a Ca-like effect on hormone release, with a progressive decrease in secretion at increased Mg. Although its mechanism is not yet clear, the low Mg effect appears to impair principally the process of hormone release rather than its biosynthesis or storage.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02408542
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  • 5
    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
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  • 6
    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
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  • 7
    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
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  • 8
    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
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  • 9
    Electronic Resource
    Electronic Resource
    Blood/bone disequilibrium: IV. Reciprocal effects of calcium and phosphate concentrations on ion fluxes (1980)
    Springer
    Calcified tissue international 32 (1980), S. 229-236 
    Details
    ISSN: 1432-0827
    Keywords: Bone ; Ion influxes ; Calcium ; Phosphate ; Exchange
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Quantitative measurements were made of the ion fluxes of calcium and phosphate into and from calvaria (mouse or rat) when clamped in specially designed micro-Ussing chambers. The effects of varying concentrations of calcium were examined on the influx and efflux of calcium and of its counterion, phosphate. A comparable series of experiments was performed with varying phosphate concentrations. Both ions, as their concentrations increased, depressed their own influx, increased their own efflux, and significantly increased the equilibrium concentration, E/K, supported by the calvaria. Similarly, both ions, as their concentrations increased, affected the influx or efflux of their counterion only slightly but did depress the counterion's equilibrium level, E/K, significantly. In spite of these changes it was shown that calvaria effectively buffered the medium at physiological concentrations of calcium and phosphate. The buffering capacity, however, was small, and the balance, E/K, was modified by small uptake or loss of either ion. The small size of the interacting mineral pool was confirmed by direct measurement of the rapidly exchanging fractions of both calcium or phosphate. They were only ∼1% of the total ions present. The significance of these findings is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02408546
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  • 10
    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
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  • 11
    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
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  • 12
    Electronic Resource
    Electronic Resource
    Total body bone mineral and lean body mass by dual-photon absorptiometry (1981)
    Springer
    Calcified tissue international 33 (1981), S. 365-368 
    Details
    ISSN: 1432-0827
    Keywords: Absorptiometry ; Osteoporosis ; Spinal bone ; Bone mineral content ; Neutron activation ; Calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Dual-photon absorptiometry using153Gd (44 and 100 keV) was used to measure the bone mineral content (BMC) of the trunk and of the total body (TBBM) in 7 volunteers with no overt bone disease. These values were compared to those obtained with partial-body neutron activation of calcium (trunk Ca). The trunk Ca seemed to represent best a 60 × 30 cm area; the correlation coefficient with the corresponding BMC in that area was 0.97 (SEE ⋍ 7%). Trunk Ca was also highly correlated with TBBM (r=0.96; SEE=8%) and with radius BMC (r=0.92; SEE=11%), but the correlations with the BMC of smaller subareas of the trunk were lower (r⋍0.9; SEE ∼ 12%). The BMC of the lumbar spine was only moderately correlated with trunk Ca, radius BMC and TBBM (r ∼ 0.82; SEE ∼ 18%), and only slightly more associated with trunk BMC (r ∼ 0.88; SEE ∼ 14%). The BMC of the combined lumbar-thoracic spine showed higher correlations with trunk Ca, radius BMC and TBBM (r ∼ 0.87; SEE ∼ 13%), and trunk BMC (r=0.93; SEE ∼ 10%). An accurate and sensitive measure of spinal status requires a direct measurement of that area.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02409457
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  • 13
    Electronic Resource
    Electronic Resource
    Effects of a bone resorptive factor from human cancer ascites fluid on rat bone cell calcium and cyclic AMP (1980)
    Springer
    Calcified tissue international 30 (1980), S. 191-197 
    Details
    ISSN: 1432-0827
    Keywords: Bone cells ; Cyclic AMP ; Calcium ; Ascites fluid resorptive protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The effects of a bone resorptive protein isolated from human cancer ascites fluid on bone cell calcium and cyclic AMP were studied with fetal rat cells. The osteoclast-activating factor increased bone cell calcium uptake at 37°C and 4°C with no direct effects on calcium efflux. Concentrations of the resorptive factor that increased in vitro bone resorption and cell calcium uptake had no effect on cyclic AMP. The effects of the protein on calcium uptake were not specific for bone cells, and large increases were also observed in isolated fetal rat skin cells. These studies suggest that increases in the permeability of the cell membrane to calcium are involved in the mechanism of action of the ascites fluid resorptive protein.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02408627
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  • 14
    Electronic Resource
    Electronic Resource
    Effects of pyrophosphate and diphosphonates on the dissolution of hydroxyapatites using a flow system (1980)
    Springer
    Calcified tissue international 31 (1980), S. 153-159 
    Details
    ISSN: 1432-0827
    Keywords: Hydroxyapatite ; Dissolution ; Pyrophosphate, Diphosphonates ; Calcium ; Phosphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Pyrophosphate and diphosphonate ions have been said to diminish the dissolution of hydroxyapatite crystals, because they lower the equilibrium concentrations of calcium and phosphate ions in the bulk solution around hydroxyapatite crystals in a closed system. However, in a closed system these effects are not necessarily due to an effect on dissolution alone. In this paper we have used a continuous flow system to study the effects of pyrophosphate and two diphosphonates, ethane-1-hydroxy-1,1-diphosphonate and dichloromethane diphosphonate, on the dissolution of hydroxyapatite. All three compounds decreased markedly the rate of dissolution of hydroxyapatite as well as the exchangeable pools of calcium and phosphate ions around the cystals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02407176
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  • 15
    Electronic Resource
    Electronic Resource
    Calcium homeostasis and bone pathology in magnesium deficient rats (1980)
    Springer
    Calcified tissue international 31 (1980), S. 231-238 
    Details
    ISSN: 1432-0827
    Keywords: Magnesium ; Bone ; Calcium ; Parathyroid gland
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Calcium homeostasis and bone pathology were studied in weanling rats fed a low (70 ppm) magnesium diet for 2–21 days. The rats developed significant, progressive hypercalcemia after 6 days on the diet. The increase in blood calcium was accompanied by progressive hypoactivity of the parathyroid gland (PTG), as determined by histologic and morphometric analyses. Thus hyperactivity of the PTG could not have been responsible for the hypercalcemia observed. Histologic examination of femora and humeri from magnesium-deficient rats showed progressive subperiosteal hyperplasia, consisting of undifferentiated osteoprogenitor cells and fibrous tissue, after 7 days of deficiency. The presence of unmineralized osteoid tissue in the metaphyses indicated that mineralization was not proceeding normally. The alterations in differentiation of osteoprogenitor cells, together with the failure of mineralization, resulted in significantly lower rates of bone formation (as measured by fluorochrome labeling) in the magnesium-deficient rats. Basophilic cementing lines and inactive osteocytes in the cortices of bones from magnesium-deficient rats indicated that bone resorption was also severely reduced in magnesium deficiency. We postulate that bone magnesium depletion (66% by day 21) has a direct negative effect on osteoblastic and osteocytic activity, and may explain, in part, the decreased responsiveness of bone to parathyroid hormone (PTH) that has been observed in magnesium-deficient animals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02407186
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  • 16
    Electronic Resource
    Electronic Resource
    Rhythmic dentinogenesis in the rabbit incisor: Allometric aspects (1980)
    Springer
    Calcified tissue international 32 (1980), S. 45-53 
    Details
    ISSN: 1432-0827
    Keywords: Dentin ; Periodicity ; Allometry ; Calcium ; Sulfur
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary We have described differences in the aspects of biological rhythms for calcium and sulfur deposition on the labial and lingual sides of the growing rabbit incisor, where growth occurs along a spiral axis. The calcium oscillations appear to be smoother on the labial side than on the lingual side. The lingual side is characterized by high-frequency rhythms with high amplitudes which possess the greatest percent of the power (Fourier analysis). These observations also reflect a difference in behavior of the mean Ca concentration across the labial and lingual sides. Sulfur rhythms on the labial side have higher amplitudes than those on the lingual side, but systematic differences in distribution of power between high and low frequencies is not as pronounced as in the case of Ca. The differences in Ca rhythms reflect differences in the growth rates of incisors on either side of the spiral axis. The labial side grows slightly faster than the lingual side, and its odontoblasts secrete Ca along the spiral axis and toward the pulp cavity at the same time. Thus the resultant direction of growth is more nearly opposite the extension of the occlusal end on the labial side, and Ca is consequently deposited over a wider area relative to that on the lingual surfaces. On the lingual side, Ca is deposited within a more limited area, and growth must therefore be continuous at high frequencies. The distribution of Ca on both sides of the tooth reflects these differences in growth rate and periodicity in two ways. First, given a unit area of tooth, the calcium concentration on the labial side is less than that of the lingual side. Second, whereas the calcium concentration on the labial side declines rapidly from the enamel-dentin junction to the pulp cavity, it is uniformly high across the lingual side because its growth is more continuous at high frequencies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02408520
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  • 17
    Electronic Resource
    Electronic Resource
    Effects of 1α-hydroxy vitamin D3 on the rachitic chick intestine: A comparison to the effects of 1,25-dihydroxyvitamin D3 (1980)
    Springer
    Calcified tissue international 32 (1980), S. 9-17 
    Details
    ISSN: 1432-0827
    Keywords: 1α-Hydroxy vitamin D3 ; 1,25-Dihydroxyvitamin D3 ; Calcium ; Transport ; Intestine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The timed sequence of events following the oral administration of 1α-hydroxy vitamin D3 (1αOHD3) to rachitic chicks was compared to that following a comparable dose of 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3). RNA polymerase activity was maximally increased 20% by 1αOHD3 within 1 to 2 h and returned to control values after 8 h. Alkaline phosphatase activity was stimulated by 4 h and was maximal (3- to 5-fold increase) at 24 h. Calcium binding protein (CaBP) was detected initially within epithelial cells at the proximal end of the villus (just above the crypt) 6 to 8 h after 1αOHD3 administration, in epithelial cells lining the proximal half of the villus by 24 h, and in epithelial cells along nearly the entire villus by 48 h. At no time did goblet cells contain CaBP. Serum calcium concentrations were significantly elevated in 2 h and maximal by 12 h (an increase of 3.6 mg/dl). Calcium accumulation by the intestinal mucosa in vitro was increased by 6 to 8 h and maximal (60% increase over controls) at 24 h. Phosphate accumulation by the intestinal mucosa in vitro was increased by 6 h and maximal (105% increase over controls) between 8 and 24 h. 1,25(OH)2D3 increased CaBP and calcium accumulation by 4 h, 2 h sooner than did 1αOHD3. 1,25(OH)2D3 decreased serum calcium levels and increased serum phosphate levels at 2 h unlike 1αOHD3. No difference in the effects of these compounds on alkaline phosphatase activity, RNA polymerase activity, and phosphate accumulation could be demonstrated. These results are consistent with the possibility that 1αOHD3 may not require conversion to 1,25(OH)2D3 for all of its biological effects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02408517
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    In vitro perifusion for the study of parathyroid hormone secretion: Effects of extracellular calcium concentration and beta-adrenergic regulation on bovine parathyroid hormone secretion in vitro (1980)
    Springer
    Calcified tissue international 32 (1980), S. 19-27 
    Details
    ISSN: 1432-0827
    Keywords: Perifusion ; Parathyroid hormone ; In vitro ; Calcium ; Beta regulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary An in vitro perifusion system was used to study parathyroid hormone (PTH) secretion in response to calcium (Ca) and beta-adrenergic agents. Perifused parathyroid tissue responded to changes in Ca within the physiologic range during experiments up to 5 h. There was rapid secretory stimulation after exposure to low Ca, with the maximum response being observed at 20 min. Normal bovine glands showed a Ca-independent nonsuppressible component of PTH release at concentrations of Ca above physiologic. 1-isoproterenol produced rapid stimulation of PTH release, the response being blocked by a beta antagonist. The maximum secretory response to either low Ca (0.5 mM) or 1-isoproterenol (10−5 M) was enhanced when the two stimuli were applied simultaneously. The response to isoproterenol was blocked by raising Ca to 2.5 mM. Although d,l-propranolol (10−4 M) caused mild suppression of PTH release at a Ca of 1.25 mM, it did not cause additional suppression at 2.5 mM Ca nor did it decrease the response to 0.5 mM Ca stimulation. The secretory response of the gland to low Ca was sustained at a level more than double the baseline rate. The response to isoproterenol was more transient, with a return to or toward baseline secretion within 60 min. These results suggest that beta agonists and low Ca have separate but related mechanisms for stimulating PTH release and may affect different pools of hormone. The perifusion system described is a relatively simple technique for assessing the kinetics and interactions of various stimulators of PTH secretion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02408518
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  • 19
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    Rhythmic dentinogenesis in the rabbit incisor: Circadian, ultradian, and infradian periods (1980)
    Springer
    Calcified tissue international 32 (1980), S. 29-44 
    Details
    ISSN: 1432-0827
    Keywords: Rabbit ; Dentin ; Calcium ; Sulfur ; Periodicity ; Circadian ; Ultradian
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary We have identified a variety of biological rhythms involved in the apposition and mineralization of dentin in the rabbit incisor. Animals were injected during the day or night with lead acetate at 2-week intervals—to provide biological time markers in forming dentin—and transverse undecalcified sections of the lower incisors were prepared for electron microprobe analysis. The positions of the lead markers were identified, and the continuous distribution of calcium and sulfur was measured at 1 µm intervals between the markers. In thin sections stained with hematoxylin after decalcification, the widths of a series of structural increments (bands) were measured with an ocular micrometer. Fourier analysis of the data revealed spectra of structural and compositional rhythms with a range of periodicities which extended from a matter of hours [ultradian (〈24 h)] to days [infradian (〉24 h) and circadian (approximately 24 h)]. The structural and compositional rhythms appeared to be independent to the extent that they did not necessarily have the same periods, or amplitudes. Nor were there simple phase relationships between all of the rhythms. At some times, Ca and S fluctuations are inversely proportional (180° out of phase), but in other cases they are directly proportional or out of phase by varying degrees other than 180°. The analyses thus suggest that calcium and sulfur deposition (representing mineral and glycosaminoglycan deposition, respectively) are not simply inversely proportional, and that the hematoxylin-stained structural increments did not solely reflect differences in the distribution of the mineral components in dentin.
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    URL: http://dx.doi.org/10.1007/BF02408519
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  • 20
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    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
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  • 21
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    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.
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    URL: http://dx.doi.org/10.1007/BF02405373
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    Effects of age and sex on the regulation of plasma 1,25-(OH)2-D by phosphorus in the rat (1981)
    Springer
    Calcified tissue international 33 (1981), S. 477-484 
    Details
    ISSN: 1432-0827
    Keywords: 1,25-(OH)2-D ; Calcium ; Phosphorus ; Sex ; Age
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Dietary phosphate deprivation in women, but not men, is accompanied by a fall in plasma PO4 and a rise in plasma 1,25-(OH)2-vitamin D concentrations. In contrast, young male rats exhibit a fall in plasma PO4 and a rise in plasma 1,25-(OH)2-D concentrations in response to PO4 deprivation. To evaluate whether age and sex influence basal plasma 1,25-(OH)2-D levels and their regulation by PO4 deprivation, plasma 1,25-(OH)2-D, PO4, and Ca levels were measured in male and female rats ranging in age from 6 weeks to 6 months while they were eating normal or low PO4 diets for 1 to 16 days. Similar observations were also made in 6-week-old castrated male and female rats, males replaced with testosterone, and females replaced with estradiol. Basal plasma 1,25-(OH)2-D levels were higher in 6-week-old males (228±76 pmol/l) than in 6-week-old females (148±62 pmol/l;P〈0.01) and declined by age 11 weeks to stable levels averaging about 100 pmol/l without sex difference. Dietary PO4 deprivation resulted in a three-to fourfold increase in plasma 1,25-(OH)2-D concentrations regardless of age and sex, accompanied by a correlated rise in serum Ca concentrations. Castration of 6-week-old males and females eliminated the sex difference in basal plasma 1,25-(OH)2-D levels and appeared to enhance the elevation of plasma 1,25-(OH)2-D concentrations in response to PO4 deprivation in females. Although gonadal hormones may modify basal plasma 1,25-(OH)2-D levels, they are not required for the augmentation of plasma 1,25-(OH)2-D levels in response to PO4 deprivation.
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    URL: http://dx.doi.org/10.1007/BF02409477
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  • 23
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    Factors in response to treatment of early postmenopausal bone loss (1981)
    Springer
    Calcified tissue international 33 (1981), S. 575-581 
    Details
    ISSN: 1432-0827
    Keywords: Osteoporosis ; Vitamin D ; Bone mineral ; Estrogen ; Aging ; Thiazide ; Fluoride ; Calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Bone mineral content (BMC) was measured by125I photon absorptiometry every 3 months in 264 normal females (45–54 years) over a 2-year period together with serum samples for calcium, phosphate, magnesium, creatinine, alkaline phosphatases, potassium, and protein. A 48-h urinary calcium and creatinine measurement was obtained. The subjects were divided into 7 treatment groups and 3 placebo groups. Five of the treatments (thiazide, vitamin D3, fluoride + vitamin D3, fluoride, and 1αD3) were ineffective at the doses used; the annual loss of compact bone was 1.5–2.2% (-X=1.8%), similar to the loss seen with placebos. Estrogen and estrogen + thiazide, in contrast, produced a 1.34% annual increase of BMC. The subjects were divided into groups with low, medium, and high initial BMC. Also, individual regressions for bone change were calculated and the subjects were divided into groups of responders, maintainers, and losers (annual change of 〉0%, 0 to −1%, and 〉−1%, respectively). The initial BMC status did not consistently affect bone or biochemical responses to the therapeutic agents. Estrogen was effective even in subjects with high BMC, whereas the other agents did not inhibit bone loss even in subjects with low initial BMC. Virtually all subjects responded to estrogen positively; in contrast we could not identify a subset of “responders” with any of the other treatments. Time since menopause appeared to influence the bone changes, although it was not a significant effect given the sample size. Bone loss in groups not treated with estrogens was 2%/year at 20 months after menopause with a decline to 1.3%/year at 45 months post-menopause. There was no apparent decline in the bone response to estrogen during the first 4 years after menopause, and in fact bone response tended to increase with time.
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    URL: http://dx.doi.org/10.1007/BF02409494
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    Control of plasma 1,25-(OH)2-vitamin D concentrations by calcium and phosphorus in the rat: Effects of hypophysectomy (1981)
    Springer
    Calcified tissue international 33 (1981), S. 485-488 
    Details
    ISSN: 1432-0827
    Keywords: 1,25-(OH)2-D ; Hypophysectomy ; Calcium ; Phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The mechanism by which dietary phosphate deprivation elevates plasma 1,25-(OH)2-D levels is not known. To evaluate the role of the pituitary in regulating plasma 1,25-(OH)2-D concentrations, the responses of plasma 1,25-(OH)2-D to dietary phosphate deprivation and, separately, to dietary calcium deprivation were evaluated in intact and hypophysectomized male rats. Among intact and hypophysectomized rats eating normal diets, plasma 1,25-(OH)2-D levels averaged 228±76 and 148±62 pmol/1, respectively (P〈0.01). During dietary phosphate deprivation, plasma 1,25-(OH)2-D levels rose to 1160±260 in intact rats and fell to 90±26 pmol/l in hypophysectomized rats (P〈0.001). By contrast, during dietary calcium deprivation, plasma 1,25-(OH)2-D levels rose in both intact and hypophysectomized animals to 856±107 and 742±279 pmol/l, respectively (NS). In response to dietary phosphate deprivation, serum calcium concentrations rose as 1,25-(OH)2-D concentrations rose in intact rats but remained at control levels in hypophysectomized rats. These results support the hypothesis that a pituitary hormone acting either directly or indirectly on the kidney mediates the increase in plasma 1,25-(OH)2-D during dietary phosphate deprivation. The hypercalcemia that occurs in rats during dietary phosphate deprivation appears to depend on the elevation of plasma 1,25-(OH)2-D.
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    URL: http://dx.doi.org/10.1007/BF02409478
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    Ultrastructural localization of calcium in the mandibular condylar growth cartilage of the rat (1980)
    Springer
    Calcified tissue international 30 (1980), S. 27-34 
    Details
    ISSN: 1432-0827
    Keywords: Ultrastructure ; Calcium ; Cartilage ; Vesicles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The potassium pyroantimonate technique was utilized for the selective subcellular localization of calcium in the mandibular condylar cartilage of 1-day-old rats. Electron dense calcium pyroantimonate precipitates were localized principally in mitochondria and at the cell membrane of the chondrocytes. In addition, small intracellular vesicles 0.1–0.2µm in diameter were observed in proximity to the cell membrane of chondrocytes of the mid-hypertrophic zone. The results suggest that these vesicles were being extruded from the cell into the extracellular matrix. Energy-dispersive analysis by X-rays confirmed that calcium is the principal cation of the electron-dense precipitates.
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    URL: http://dx.doi.org/10.1007/BF02408603
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    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.
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    URL: http://dx.doi.org/10.1007/BF02411207
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    Assessment of anin vivo diffusion chamber method as a quantitative assay for osteogenesis (1984)
    Springer
    Calcified tissue international 36 (1984), S. 77-82 
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    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.
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    URL: http://dx.doi.org/10.1007/BF02405297
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    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.
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    URL: http://dx.doi.org/10.1007/BF02405329
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  • 29
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    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.
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    URL: http://dx.doi.org/10.1007/BF02405351
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    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.
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    URL: http://dx.doi.org/10.1007/BF02405393
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    Changes in plasma bone GLA protein during treatment of bone disease (1982)
    Springer
    Calcified tissue international 34 (1982), S. 121-124 
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    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.
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    URL: http://dx.doi.org/10.1007/BF02411221
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    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.
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    URL: http://dx.doi.org/10.1007/BF02405014
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    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.
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    URL: http://dx.doi.org/10.1007/BF02405129
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    Diurnal changes in the flux of calcium toward meristems and transpiring leaves in tomato and maize plants (1981)
    Springer
    Planta 151 (1981), S. 265-271 
    Details
    ISSN: 1432-2048
    Keywords: Calcium ; Cation exchange ; Lycopersicon esculentum ; Rhythm ; diurnal Transport (calcium) ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Tomato (Lycopersicon esculentum Mill. cv. Moneymaker) and maize (Zea mays L. cv. spec.) plants were supplied with 45Ca-labeled nutrient solutions for a period of 8 or 16 h in the dark, in the light, or in a light-dark régime. Plant parts were analyzed for 45Ca content. The partitioning of 45Ca between mature leaves and meristems was shown to be affected by the presence of light. The transport of 45Ca to meristems was higher in a dark period than in a comparable light period. Experiments with excised tomato shoots yielded similar distribution patterns of 45Ca over leaves and meristems, thus excluding root pressure as the main driving force for the enhanced import of 45Ca into the meristems in the dark. Results are discussed in terms of cation-exchange transport and competition between the various calcium sinks.
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    Characterisation of the Egeria densa Planch. leaf symplast (1983)
    Springer
    Planta 158 (1983), S. 320-328 
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    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.
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    Localization of membrane-associated calcium following cytokinin treatment in Funaria using chlorotetracycline (1981)
    Springer
    Planta 152 (1981), S. 272-281 
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    ISSN: 1432-2048
    Keywords: Bryophyta ; Bud formation (moss) ; Calcium ; Chlorotetracycline ; Cytokinin ; Funaria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have investigated the changes in membrane-associated calcium that occur during cytokinin induced bud formation in Funaria hygrometrica Hedw. using the fluorescent Ca2+-chelate probe chlorotetracycline (CTC). In the target caulonema cells a localization of CTC fluorescent material becomes evident at the presumptive bud site 12 h after cytokinin treatment. By the time of the initial asymmetric division this region is four times as fluorescent as the entire caulonema cell. Bright CTC fluorescence remains localized in the dividing cells of the bud. To relate the changes in CTC fluorescence to changes in Ca2+ as opposed to membrane-density changes we employed the general membrane marker N-phenyl-1-naphthylamine (NPN). NPN fluorescence increases only 1.5 times in the initial bud cell. We conclude that the relative amount of Ca2+ per quantity of membrane increases in this localized area and is maintained throughout bud formation. We suggest that these increases in membrane-associated Ca2+ indicate a localized rise in intracellular free Ca2+ concentration brought about by cytokinin action.
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    Calcium and gibberellin-induced elongation of lettuce hypocotyl sections (1981)
    Springer
    Planta 152 (1981), S. 450-456 
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    ISSN: 1432-2048
    Keywords: Calcium ; Cell elongation ; Gibberellin ; Lactuca ; pH and growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The relationship between calcium ions and gibberellic acid (GA3)-induced growth in the excised hypocotyl of lettuce (Lactuca sativa L.) was investigated. The short-term kinetics of growth responses were measured using a linear displacement transducer. Test solutions were added either as drops to the filter paper on which the hypocotyl stood (“non-flow-past”) or by switching solution flowing past the base of hypocotyl (“flow-past”), resulting in differences in growth behavior. Drops of CaCl2 added at a high concentration (10 mM) inhibited growth within a few minutes. This inhibition was reversed by ethylenediaminetetraacetic acid (EDTA). Drops of EDTA or ethyleneglycol-bis(2-aminoethylether)-tetraacetic acid caused a rapid increase in growth rate. Growth induced by EDTA was not further promoted by GA3. A continuous H2O flow resulted in growth rates comparable to those in response to GA3. Addition of CaCl2 to the flow-past medium inhibited growth and this inhibition was reversed by a decrease in CaCl2 concentration. The growth rate was found to be a function of CaCl2 concentration. When a constant CaCl2 concentration was maintained by the flow-past medium, a shift in pH from 5.5 to 4.25 had no obvious effect on hypocotyl elongation. Gibberellic acid was found to reverse the inhibitory effect of CaCl2, causing an increase in growth rate similar to that found previously when GA3 was added to hypocotyls grown in H2O under non-flow-past conditions. We propose that gibberellin controls extension growth in lettuce hypocotyl sections by regulating the uptake of Ca2+ by the hypocotyl cells.
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    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.
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    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 
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    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.
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    The role of calcium in stalk development and in phosphate acquisition in Caulobacter crescentus (1984)
    Springer
    Archives of microbiology 138 (1984), S. 140-152 
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    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.
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    Elemental analysis of particles in fungal zoospores (1984)
    Springer
    Archives of microbiology 139 (1984), S. 102-104 
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    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.
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    The role of calcium ions in phytochrome-mediated germination of spores of Onoclea sensibilis L. (1984)
    Springer
    Planta 160 (1984), S. 12-20 
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    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.
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    The use of irradiated pollen for differential gene transfer in wheat (Triticum aestivum) (1983)
    Springer
    Theoretical and applied genetics 65 (1983), S. 103-111 
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    ISSN: 1432-2242
    Keywords: Pollen irradiation ; Wheat ; Differential gene transfer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The use of irradiated pollen to bring about limited gene transfer in wheat has been investigated. Doses of X-rays of 2Kr, 3Kr and 5Kr were used to generate M1 progeny between maternal and paternal genotypes differing in quantitative and major gene characters. Cytological studies of M1 plants revealed hybrids with widespread aneuploidy and structural rearrangements in the paternal genome. These effects resulted in phenotypic variation between M1 progeny and complex multivalent formation at meiosis. All M1 plants at the 5Kr and 3Kr doses were sterile and all but 2 plants at the 2Kr dose. Studies of the two M2 families from these plants revealed disturbances in genotype frequencies for some of the marker loci with an excess of maternal homozygotes and a deficit of paternal homozygotes. This was also reflected in a more maternal appearance for quantitative characters. These results are interpreted as showing that irradiation damage to the paternal genome in M1 plants results in the differential transmission of maternal alleles.
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    Chitinase as a possible resistance factor for higher plants (1983)
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    Theoretical and applied genetics 65 (1983), S. 171-172 
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    ISSN: 1432-2242
    Keywords: Resistance ; Genetic engineering ; Yellow rust ; Wheat ; Chitinase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Virulence and resistance may act on the same biochemical mechanisms. Because Erwinia-virulence on potato depends on the lysis of cell walls of the host, resistance may depend on the lysis of cell walls of the parasite. An example is given with yellow rust on wheat.
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    The Tom Thumb dwarfing gene Rht3 in wheat (1983)
    Springer
    Theoretical and applied genetics 66 (1983), S. 249-256 
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    ISSN: 1432-2242
    Keywords: Wheat ; Dwarfism ; Yield ; Quality
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The effects of the ‘Tom Thumb’ Rht3 dwarfing gene in wheat on plant height, yield components and grain quality in field trials of random inbred lines from two ‘Minister Dwarf’ (Rht3) x rht3 crosses are described. Limited genetic increases in Rht3 plant height, up to 70 cm, were achieved by incorporating genes from the extremely tall variety ‘April Bearded’. Amongst lines from the higher yielding cross, the dwarfing gene did not reduce grain yield but was associated with an increase in grain number of over 25%. Although Rht3 reduced grain protein content by up to 0.8%, breadmaking quality, as measured by SDS sedimentation values and baking tests, was not affected. A controlled environment experiment with near-isogenic Rht3 and rht3 lines indicated that reduced grain size in the dwarfs is a competitive response to the increase in fertility rather than a primary effect of the dwarfing gene.
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    The chromosomal location of malate dehydrogenase isozymes in hexaploid wheat (Triticum aestivum L.) (1983)
    Springer
    Theoretical and applied genetics 64 (1983), S. 255-258 
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    ISSN: 1432-2242
    Keywords: Triticum aestivum ; Wheat ; Malate dehydrogenase ; Chromosomal location
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The malate dehydrogenase (E.C. no 1.1.1. 37) of Triticum aestivum L. cv. Chinese Spring, shows two activity zones. The results obtained support the hypothesis that the malate dehydrogenase isozymes of zone II are dimers composed of the six possible combinations of subunits coded by triplicate genes located in the long arms of chromosomes of the homoeologous group 1.
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    Chromosome variation in wheat plants regenerated from cultured immature embryos (1984)
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    Theoretical and applied genetics 67 (1984), S. 249-255 
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    ISSN: 1432-2242
    Keywords: Wheat ; Plant regeneration ; Chromosome variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A cytological study has been made of plants regenerated from cultured immature embryos of four wheat cultivars (Triticum aestivum, 2n = 6x = 42). In total, 29% of the 192 plants examined were aneuploid with a range in chromosome numbers of 38–45. Evidence of chromosome structural changes was also found. This variation occurred in regenerants of all four cultivars, but there were large differences in the proportions of aneuploids arising from individual cultures which meant that no significant differences could be demonstrated between cultivars. Chromosome abnormalities were present in plants regenerated both from embryogenic cultures and from cultures in which the origin of shoots could not be distinctly defined.
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    Wheat microspore embryogenesis during in vitro anther culture (1984)
    Springer
    Theoretical and applied genetics 67 (1984), S. 439-442 
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    ISSN: 1432-2242
    Keywords: Wheat ; Multicellular pollen grains ; Embryos ; Cytology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Cytological analysis of microspore embryogenesis during in vitro culture reveals a high mortality in the first week and a latency phase of about one week before the first embryogénic mitosis. Genotypic differences observed during our wheat anther culture do not seem to originate at the induction level but are linked to the different abortion rates.
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    The regeneration of plants from frozen pollen embryos and zygotic embryos of wheat and rice (1984)
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    Theoretical and applied genetics 67 (1984), S. 525-528 
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    ISSN: 1432-2242
    Keywords: Cryopreservation ; Embryo culture ; Haploids ; Wheat ; Rice ; Germplasm bank
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Anther culture derived pollen embryos and immature zygotic embryos of wheat and rice, frozen in liquid nitrogen in the presence of dimethyl sulfoxide, sucrose and glycerol, have been revived. The retrieved cultures proliferated and/or regenerated shoots and plantlets. The prospects of the cryopreservation of embryos for the conservation and multiplication of germplasm and the possibility of the establishment of ‘Germplasm Banks’ are discussed.
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    The genetic control of grain esterases in hexaploid wheat (1984)
    Springer
    Theoretical and applied genetics 68 (1984), S. 219-226 
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    ISSN: 1432-2242
    Keywords: Hexaploid genotypes ; Allelic variation ; Esterase ; Isozymes ; Isoelectric focusing ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Analysis of grain esterase isozymes in Chinese Spring aneuploid genotypes by IEF confirmed that genes on the long arms of chromosomes 3A, 3B and 3D (Est-5) control the production of 19 isozymes. Allelic variants have been found for the isozyme pattern controlled by each chromosome. Segregational data involving null alleles and complex phenotypic differences indicate that the wheat grain esterases are encoded by three compound and probably homoeoallelic loci, each capable of producing at least six different isozymes. In a sample of 138 hexaploid genotypes, seven alleles were distinguished.
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    A computer-assisted examination of the storage protein genetic variation in 841 accessions of Triticum dicoccoides (1984)
    Springer
    Theoretical and applied genetics 69 (1984), S. 79-86 
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    ISSN: 1432-2242
    Keywords: Electrophoresis ; Endosperm ; Proteins ; Emmer ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Triticum turgidum L. var. dicoccoides (wild emmer) is an important genetic resource for increasing the protein content of common wheat (Triticum aestivum L.). Many studies have shown that the presence or absence of bands in sodium dodecyl sulfate polyacrylamide (SDS-PAGE) electrophoregrams of wheat storage proteins to be of a purely genetic character. A total protein extraction and SDS-PAGE technique was used to estimate the storage protein genetic variability among 841 accessions of wild emmer collected from various ecological regions in the Middle East. In addition, a computer data bank was developed, recording the onedimension electrophoregram bands for each accession by molecular weight (MW) and relative Coomassie Blue staining intensity as determined from densitometer scans. Analyses of this information are being used to identify specific accessions for further study by two dimension electrofocusing-electrophoresis and breeding and genetic analyses. The computer-assisted analyses indicated that the greatest genetic variability occurs for proteins in the high MW region (above 70,000 MW) followed by those in the medium range (70,000 to 33,300 MW). Comparatively little variability was revealed for protein subunits of below 33,300 MW.
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    Chromosomal assignment of genes controlling salt-soluble proteins (albumins and globulins) in wheat and related species (1984)
    Springer
    Theoretical and applied genetics 69 (1984), S. 167-172 
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    ISSN: 1432-2242
    Keywords: Chromosomal location ; Genetic control ; Salt soluble proteins ; Wheat ; Barley ; Rye
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Salt-soluble proteins from the endosperms of wheat, barley, and rye have been separated by nonequilibrium electrofocusing x electrophoresis. Genes encoding 14 of the 25 components observed in wheat have been unambiguously assigned to 10 different chromosomes (1B, 3B, 3D, 4A, 4D, 5B, 6B, 6D, 7B, 7D) by analysis of the compensated nulli-tetrasomic series. Five more wheat proteins seem to be controlled by group 2 chromosomes. Analysis of wheat-barley and wheat-rye addition lines has led to the location of genes for 6 out of 20 barley proteins in 4 different chromosomes (1H, 3H, 4H, 6H; 1H is homoeologous to group 7 chromosomes of wheat) and of genes for 5 out of 20 rye proteins in two different chromosomes (2R, 4R). The relationship between the proteins reported here and previously characterized ones is discussed.
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    The relationship between the Rht 1 and Rht 2 dwarfing genes and grain weight in Triticum aestivum L. spring wheat (1983)
    Springer
    Theoretical and applied genetics 66 (1983), S. 153-157 
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    ISSN: 1432-2242
    Keywords: Inheritance ; Culm-length ; GA insensitivity ; Grain weight ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The study was carried out in the first year on samples of random F5 lines, uniform in height and in heading date, of three crosses between semi dwarf spring wheat cultivars (Triticum aestivum L.), differing in grain weight and in their Rht gene. In the second year only the progenies of the early heading F5 lines were studied. All the material was grown in the absence of lodging. The culm-length genotypes of the different lines were identified by test crosses and by a seedling GA response test. No differences in grain weight were found between the two semi dwarf genotypes (Rht 1Rht1 rht 2rht2 and rht 1rht1 Rht 2Rht2). The tall genotype (rht 1rht1 rht 2rht2) was significantly higher in grain weight than the two semi dwarf genotyes and the grain weight of these genotypes exceeded markedly the grain weight of the dwarf genotype (Rht 1Rht1 Rht 2Rht2). These genotypic effects were independent of differences in plant height, heading date or number of grains per spike.
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    Inheritance of glutenin subunits in F1 seeds of reciprocal crosses between European hexaploid wheat cultivars (1983)
    Springer
    Theoretical and applied genetics 64 (1983), S. 103-107 
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    ISSN: 1432-2242
    Keywords: Glutenin ; Wheat ; Co-dominance ; Bread-making
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Ten pairs of reciprocal crosses have been made between wheat cultivars which show differences in their glutenin subunit compositions. The F1 seed glutenin subunit composition was studied by means of polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate (SDS). The results indicate that all the high molecular weight (HMW) and medium molecular weight (MMW) subunits (from 133,000 to 65,000 daltons) are transmitted to the F1 seed generation from the parental cultivars. In accordance with the triploid nature of the heterozygous endosperm (3n) and with the maternal and paternal gene dosage ratio (2∶1) in the endosperm itself, a significant effect of maternal parent is registered when comparing pairs of reciprocal seeds. Genes coding for the glutenin subunits are expressed whatever their doses are (one, two, or three) in the hybrid endosperm; thus the glutenin subunits inheritance is consistent with the co-dominant type. For one pair of the reciprocal crosses, two MMW parental bands (MW: 71,000 and 66,000) seemed absent in the F1 seed patterns while a new band with an intermediate, apparent MW (68,000) appears. This phenomenon was observed when the glutenins analyzed by electrophoresis were previously separated from other endosperm proteins, and not when they were directly extracted from the ground seed. We assume that the extraction can cause interactions between moieties attached to the subunits and lead to the formation of a complex having an intermediate electrophoretic mobility.
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    Genetic studies of the crossability of hexaploid wheat with rye and Hordeum bulbosum (1983)
    Springer
    Theoretical and applied genetics 64 (1983), S. 303-307 
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    ISSN: 1432-2242
    Keywords: Crossability ; Wheat ; Rye ; Hordeum bulbosum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Crosses of wheat (Triticum aestivum L.) Group 5 chromosome substitution lines from three different cultivar backgrounds indicate that there may be multiple alleles for reduced crossability with rye (Secale cereale L.) and H. bulbosum on both 5A and 5B chromosomes. No reduction in seed set was observed from any of the 5D substitution lines. It was found that the Kr1 locus on chromosome 5B had a more pronounced affect on both rye and H. bulbosum crossability than the Kr2 locus on chromosome 5A and that the effects of both loci were cumulative. The Kr alleles affected both rye and H. bulbosum crossability in a linear, or additive, fashion. The Kr 2 allele was shown to have little effect on H. bulbosum crossability compared to a significant effect on rye crossability. Tests with tetrasomic and nulli-tetrasomic lines of ‘Chinese Spring’ indicated that the kr allele is ‘null’ or inactive in promoting crossability while the Kr allele is active in reducing crossability to both rye and H. bulbosum. Thus, extra doses of the kr allele do not increase rye or H. bulbosum crossability in the presence of the corresponding Kr allele.
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    URL: http://dx.doi.org/10.1007/BF00274168
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    Genetic control of α-Amylase production in wheat (1983)
    Springer
    Theoretical and applied genetics 64 (1983), S. 309-316 
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    ISSN: 1432-2242
    Keywords: Wheat ; α-Amylase ; Isozymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary An analysis of the α-amylase isozymes in GA-treated endosperm of wheat nullisomic-tetrasomics shows that there is more variation at the α-Amy-1 and α-Amy-2 homoeoallelic loci than was previously thought. Among the 16 isozymes produced by genes on the group 7 chromosomes, most could be definitely established as products of a single homoeoallele. Inter-varietal allelic differences would be expected at such loci and clear variation was found in isozymes produced by chromosomes 6B and 7B. The latter allele, α-Amy-B2b carried by the variety ‘Hope’, was used to locate the enzyme structural gene within chromosome 7B relative to the centromere and five other gene markers. The nature of the α-Amy-B2b phenotype and the rare non-parental isozyme patterns found among the recombinant lines indicates that the locus is large and compound, probably involving some degree of intra-locus gene duplication.
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    URL: http://dx.doi.org/10.1007/BF00274170
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    Characterisation of high molecular weight gliadin and low-molecular-weight glutenin subunits of wheat endosperm by two-dimensional electrophoresis and the chromosomal localisation of their controlling genes (1983)
    Springer
    Theoretical and applied genetics 66 (1983), S. 29-37 
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    ISSN: 1432-2242
    Keywords: Gliadin ; Glutenin ; Tticum ; Wheat ; Endosperm
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Gliadins, here defined as those proteins of defatted wheat endosperm which dissolve in 70% (v/v) ethanol at room temperature, were fractionated by gel filtration using Sephadex G-100. The protein which eluted with the void volume of the column, often described as high-molecular-weight (HMW) gliadin, was fractionated by the two different, two dimensional gel electrophoresis procedures of O'Farrell (1975) and O'Farrell et al. (1977). The next two fractions to elute from the gel column, ω-gliadin and α-, β-, γ-gliadin, were analysed similarly. The subunits of HMW gliadin and the classical (i.e. non-aggregated) gliadins map at distinctive positions on the electrophoregrams, the majority of the HMW gliadin subunits being more basic and having a slightly slower electrophoretic mobility than the α-, β-, γ-gliadins. These experiments demonstrate that those gliadins which aggregate to form HMW gliadin are distinct molecular entities and thus coded by different genes to those gliadins which do not aggregate. Glutenin, here prepared by a modification of the pH 6.4 precipitation procedure of Orth and Bushuk (1973), was also analysed by two-dimensional electrophoresis. The low-molecular-weight subunits were found to correspond exactly with the HMW gliadin subunits. Using the nullisomic-tetrasomic lines and the ditelocentric lines of ‘Chinese Spring’, the genes controlling the synthesis of all the major HMW gliadin subunits were shown to be located on the short arms of chromosomes 1A, 1B and 1D, as are the genes coding for the ω-gliadins and the majority of the γ-gliadins.
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    URL: http://dx.doi.org/10.1007/BF00281844
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    Evidence for maternal effect in the inheritance of grain protein in crosses between cultivated and wild tetraploid wheats (1984)
    Springer
    Theoretical and applied genetics 67 (1984), S. 521-524 
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    ISSN: 1432-2242
    Keywords: Wheat ; Triticum ; Grain protein ; Grain weight ; Maternal effect ; Cytoplasmic effect
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Reciprocal crosses were made between cultivated wheat (Triticum turgidum var. ‘durum’) and a high-protein line of wild tetraploid wheat (T. turgidum var. ‘dicoccoides’). F1 grains (on maternal spikes) were very similar to the selfed grains on the maternal parent in protein percentage, weight and protein content. These traits were also analyzed in F3 grains developed on F2 spikes of segregating populations derived from reciprocal crosses between the same cultivated parent and another high-protein line of var. ‘dicoccoides’. No significant differences in the mean values of these traits were found between the reciprocal crosses, indicating no cytoplasmic effect. It has been concluded that these grain characteristics are largely determined by the maternal plant.
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    URL: http://dx.doi.org/10.1007/BF00264897
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    Heritability of grain yield, plant height and test weight of a population of winter wheat adapted to Southwestern Ontario (1984)
    Springer
    Theoretical and applied genetics 68 (1984), S. 21-23 
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    ISSN: 1432-2242
    Keywords: Wheat ; Heritability ; Yield ; Height
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Grain yield, plant height and test weight were studied in a population of winter wheat (Triticum aestivum L.). The population consisted of F2 bulk populations of 42 crosses among 11 genotypes adapted to S. W. Ontario. Heritabilities were: 0.30±0.32 for yield, 0.77±0.15 for height and 0.98±0.08 for test weight. Predicted genetic gain with 10% selection intensity was 0.15 t/ha for yield, 10.1 cm for height and 3.00 kg/hl for test weight. The low heritability for yield indicates that effective selection would require pedigree information and progeny tests, while the high heritabilities for height and test weight indicate that selection for these traits using single plots would be appropriate.
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    URL: http://dx.doi.org/10.1007/BF00252304
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    Increasing grain protein content of hard red winter wheat (Triticum aestivum L.) by mutation breeding (1983)
    Springer
    Theoretical and applied genetics 65 (1983), S. 41-46 
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    ISSN: 1432-2242
    Keywords: Triticum aestivum ; Wheat ; Protein ; Mutation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Poor adaptability or functional quality of much germplasm used for breeding high-protein hard red winter wheats prompted mutagenesis as an alternative means of increasing grain protein content. Four hard red winter wheat genotypes — KS644 (‘Triumph// Concho/Triumph’), ‘Kaw’, ‘Parker’, and ‘Shawnee’ — were treated with 0.40 M ethyl methanesulfonate (EMS). Advanced lines (M8-M10) were selected that had a 3-year mean grain protein advantage of 0.7% to 2.0% over controls. Increased grain protein content was generally associated with decreased grain yield and kernel weight, but some high-protein mutant lines had yields or kernel weights similar to those of original genotypes. Changes in height and lodging induced by EMS were generally favorable, most mutants being shorter and lodging less than controls, but blooming date was generally delayed, a deleterious change. One line also changed from resistant to segregating for wheat soil-borne mosaic virus. Mutant lines might be utilized in cross-breeding programs, particularly if negative pleiotropic effects and linkages are absent.
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    URL: http://dx.doi.org/10.1007/BF00276260
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    Glutenin subunits of genetically related European hexaploid wheat cultivars: Their relation to bread-making quality (1980)
    Springer
    Theoretical and applied genetics 58 (1980), S. 107-111 
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    ISSN: 1432-2242
    Keywords: Glutenin ; Wheat ; Bread-making ; Chromosomal control
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The subunit composition of glutenin from 47 European wheat cultivars was studied using SDS-polyacrylamide gel electrophoresis. These cultivars are genetically related since they originate from the same stock. Moreover, the diversity of sample, containing cultivars with very different French bread-making qualities, makes it possible to investigate the relationship between glutenin subunit composition and bread-making quality. 16 electrophoretic types of glutenin subunits could be distinguished: these were grouped into four classes. Depending on the cultivar, six to eight glutenin subunits with MW more than or equal to 62,000 were detected. Subunits 3 and 5, with an approximate MW of 122,000 and 108,000 respectively, seem to play a prominent role on bread-making quality; they were found in cultivars of good quality and were absent in those unsuitable for making French bread. Two other subunits (9 and 10; MW: 71,000 and 66,000, respectively) have a less defined influence but may be needed in some types of glutenin structure. Aneuploid analysis shows that in ‘Chinese Spring’, subunit 5 is coded by a gene on the long arm of chromosome 1B. The location of genes coding for subunits 3, 9 and 10 could not be determined.
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    URL: http://dx.doi.org/10.1007/BF00263099
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    Genetic studies of frost resistance in wheat (1981)
    Springer
    Theoretical and applied genetics 59 (1981), S. 145-152 
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    ISSN: 1432-2242
    Keywords: Wheat ; Frost resistance ; Diallel cross ; F2monosomics ; Substitutions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Genetic studies of frost resistance were performed on various wheat varieties using diallel, F2 monosomic and substitution analysis. A six-parental cross including reciprocals was carried out, and F1 hybrids and their parents were used for the freezing tests under controlled conditions. Both the general combining ability (GCA) and the specific combining ability (SCA) were significant, indicating additive and non-additive gene action in the inheritance of frost resistance. The high GCA∶SCA ratio revealed a preponderance of additive genetic variance. No significant reciprocal differences were found between the reciprocal crosses. The variance/covariance graphical analysis indicated the partial dominance of frost sensitivity. Frost sensitive varieties had the largest number of dominant genes, while frost resistant varieties had the highest proportion of recessive genes. The magnitude of the additive component of variation was higher than that of the dominance component, and the overall measure of the degree of dominance was smaller than one, so average dominance is incomplete. The increasing and decreasing alleles are not equally frequent at all loci. In this set of wheat varieties the values of narrow and broad heritability are relatively high. F2 monosomic analysis of the winter wheat variety ‘Arthur’ crossed with the monosomics of ‘Chinese Spring’ revealed that the average frost resistance of all the 21 monosomics was lower than that of the disomic. F2 monosomic hybrids 5A, 2B, 4B and 5D proved to be relatively frost resistant, while monosomics 3A, 3B and 6D were the most sensitive. The control of frost resistance in the set of chromosome substitution lines of the variety ‘Cheyenne’ into ‘Chinese Spring’ (with the exception of 2B) indicated that the genes responsible for the frost resistance of ‘Cheyenne’ are localised in chromosomes 5A, 7A, 4B, 5B, 4D and 5D. The genetic basis of frost resistance and problems of analysis are discussed.
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    URL: http://dx.doi.org/10.1007/BF00264968
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    Monosomic analysis of genes for resistance against stem rust races in bread wheat (1981)
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    Theoretical and applied genetics 59 (1981), S. 313-316 
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    ISSN: 1432-2242
    Keywords: Triticum aestivum ; Wheat ; Puccinia graminis ; Stem rust resistance ; Monosomic analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Using monosomic analysis genes governing resistance in one wheat variety, ‘E5883’, against stem rust races 15C and 122, were located on specific chromosomes. Against race 15C, a major dominant gene, Sr6, was located on chromosome 2D of ‘E5883’ with minor modifiers found on chromosomes 4A and 6D. Against race 122, the presence of a recessive hemizygous ineffective gene, Sr8, was identified, located on chromosome 6A of variety ‘E5883’.
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    URL: http://dx.doi.org/10.1007/BF00264984
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    Analysing environments for plant breeding purposes as exemplified by multivariate analyses of long term wheat yields (1981)
    Springer
    Theoretical and applied genetics 59 (1981), S. 317-325 
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    ISSN: 1432-2242
    Keywords: Environmental evaluation ; Plant breeding ; Multivariate analysis ; Wheat ; Climatic variable
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A previous attempt to relate long term yields from the Western Australian wheat belt to climatic factors proved only partially successful. Here, principal component analysis has been used to examine the patterns of variability created by those socio-economic factors which may have obscured any underlying relationship which existed between yield and climate. In fact, these analyses revealed the existence of variation peculiar to particular groups of years, a result which could explain why many attempts to relate crop yields directly to climatic factors have proved unsuccessful. The plant breeding implications of these genotype x environment interactions are considered.
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    URL: http://dx.doi.org/10.1007/BF00264985
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    Genetic variation in wheat endosperm proteins: an analysis by two-dimensional electrophoresis using intervarietal chromosomal substitution lines (1981)
    Springer
    Theoretical and applied genetics 59 (1981), S. 361-371 
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    ISSN: 1432-2242
    Keywords: Wheat ; Endosperm ; Proteins ; Electro phoresis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The major endosperm proteins in a range of genotypes of hexaploid wheat have been fractionated by two-dimensional electrophoresis. The genotypes included nine varieties and forty four intervarietal substitution lines in which chromosomes 1A, 1B, 1D, 6A, 6B or 6D from eight of the varieties have been introduced one at a time into a common genetic background. The appearance of different protein subunits was often correlated with a chromosome substitution. This showed that many of the genes for the high molecular weight protein subunits (molecular weight range 55,000 to 140,000 determined by SDS polyacrylamide gel electrophoresis) are specified by chromosomes 1A, 1B and 1D while many of the lower molecular weight subunits (molecular weight range 30,000 to 45,000) are specified by chromosomes 6A, 6B and 6D. The different protein subunits correlated with chromosome substitution could not always be recognised in the varietal source of the substituted chromosome. The different subunits specified by homologous chromosomes in different wheat varieties may differ in isoelectric point and/or molecular weight.
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    URL: http://dx.doi.org/10.1007/BF00276450
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    Biochemical markers associated with two Mv chromosomes from Aegilops ventricosa in wheat-Aegilops addition lines (1981)
    Springer
    Theoretical and applied genetics 60 (1981), S. 5-10 
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    ISSN: 1432-2242
    Keywords: Wheat ; Aegilops ventricosa ; Addition lines ; Biochemical markers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The distribution of three biochemical markers, U-1, CM-4 and Aphv-a, -b, among wheat-Aegilops addition lines carrying Mv chromosomes from Aegilops ventricosa (genomes DvMv) has been investigated. Addition lines which had been previously grouped together on the basis of common non-biochemical characters carried marker U-1, a protein component from the 2M urea extract. The added chromosome, in the appropriate genetic background, seems to confer a high level of resistance to the eyespot disease, caused by the fungus Cercosporella herpotrichoides. The other two markers were concomitantly associated with another similarly formed group of addition lines. Both CM-4, a protein component from the chloroform:methanol extract, and Aphv-a, -b, alkaline phosphate isozymes, have been previously shown to be associated with homoeologous chromosome group 4, which suggests that the added chromosome in the second group of addition lines is 4Mv.
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    URL: http://dx.doi.org/10.1007/BF00275171
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    The role of ‘Norin 10’ dwarfing genes in photosynthetic and respiratory activity of wheat leaves (1981)
    Springer
    Theoretical and applied genetics 60 (1981), S. 81-84 
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    ISSN: 1432-2242
    Keywords: Wheat ; ‘Norin 10’ dwarfing genes ; Photosynthesis ; Respiration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A comparative analysis of eight cultivars of spring wheat (Triticum aestivum) classified by height as tall (T), semi-dwarf (D1), dwarf (D2) and very dwarf (D3) was conducted to study their efficiency of oxygen exchange during photosynthesis and dark respiration. Two cultivars were included in each height group. Cultivars carrying ‘Norin 10’ dwarfing genes (D1, D2 and D3) were found to have a significantly higher photosynthetic rate per unit leaf area than talls (T) that lack these genes. Among the ‘Norin’ gene carriers, dwarf group (D2) was most efficient, followed by very dwarf (D3) and semi-dwarf (D1). Photosynthetic rate and respiratory rate were found to have a positive relationship.
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    URL: http://dx.doi.org/10.1007/BF00282421
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    Investigation of a preferentially transmitted Aegilops sharonensis chromosome in wheat (1982)
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    Theoretical and applied genetics 61 (1982), S. 27-33 
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    ISSN: 1432-2242
    Keywords: Preferential transmission ; In situ hybridization ; C-banding ; Aegilops sharonensis ; Wheat ; Addition ; Substitution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary An attempt to produce a set of addition lines of Aegilops sharonensis to the wheat variety ‘Chinese Spring’ produced only one addition line. This was due to preferential transmission of one chromosome from Ae. sharonensis. This chromosome was studied in detail by established cytological methods of chromosome observation and by the newer techniques of C-banding and in situ hybridization of a cloned DNA sequence. The chromosome was found to be partially homologous to an Ae. sharonensis chromosome of similar behaviour in another wheat addition line. The incomplete homology of the two Ae. sharonensis chromosomes was due to the presence of a translocated segment of a wheat chromosome. — Substitution lines of the Ae. sharonensis chromosome for wheat homoeologous group 4 were produced and the Ae. sharonensis chromosome thereby designated 4 S l .
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    URL: http://dx.doi.org/10.1007/BF00261506
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    Preferential C-banding of wheat or rye chromosomes (1982)
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    Theoretical and applied genetics 63 (1982), S. 227-233 
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    ISSN: 1432-2242
    Keywords: C-banding ; Wheat ; Rye ; Triticale
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Using different stains, wheat chromosomes could be distinguished from rye chromosomes by preferential staining. C-bands of rye chromosomes were preferentially stained with Giemsa while those of wheat chromosomes were preferentially stained with either Leishman or Wright stain. Preferential staining aids the identification of wheat and rye chromosomes and chromosome segments and in particular the recognition of wheat/rye chromosome substitutions and translocations.
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    URL: http://dx.doi.org/10.1007/BF00304000
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    Characterization of the multigene family coding for HMW glutenin subunits in wheat using cDNA clones (1983)
    Springer
    Theoretical and applied genetics 67 (1983), S. 87-96 
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    ISSN: 1432-2242
    Keywords: HMW glutenin subunit genes ; cDNA clones ; Tandem DNA repeats ; Chromosomal location ; Gene copy number ; Wheat ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary cDNA clones encoding wheat HMW glutenin subunits have been isolated from a cDNA bank made to poly A+ RNA from developing wheat endosperm var. Chinese Spring. One such clone, pTag 1290, has enabled us to identify the HMW glutenin mRNA species. The DNA sequence of this clone has been partially determined and it contains several tandem DNA repeats. The sequence is discussed in relation to the generation of the HMW glutenin subunit gene family. Analysis of the organization of the HMW glutenin sequences in the wheat genome revealed that the genes encoding HMW glutenin subunits exist in low copy number and are located on the long arm of each of the homoeologous group 1 chromosomes.
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    URL: http://dx.doi.org/10.1007/BF00303930
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    Responses of alloplasmic (cytoplasm=Triticum timopheevii) and euplasmic wheats (Triticum aestivum) to photoperiod and vernalization (1983)
    Springer
    Theoretical and applied genetics 66 (1983), S. 61-66 
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    ISSN: 1432-2242
    Keywords: Triticum aestivum ; T. timopheevii ; Wheat ; Photoperiod ; Vernalization ; Male sterility ; Alloplasmic hybrids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Studies were conducted to determine the influence of the male sterility-inducing cytoplasm of Triticum timopheevii (Zhuk.) Zhuk. on response of several common winter wheat (T. aestivum L.) nuclear genotypes to photoperiod and vernalization. Comparative studies of cytoplasmic substitution lines provide information on the role of the cytoplasmic genetic mechanism in growth and development. In the case of cytoplasmic male sterility-based hybrid production systems, ubiquity of sterility-inducing cytoplasm in derived hybrids warrants thorough characterization of its influence on plant phenotype. Factorial combinations of cytoplasm (T. timopheevii and T. aestivum), nuclear genotype, and photoperiod or vernalization treatments were evaluated under hydroponic conditions in controlled environment chambers. Interaction of cytoplasm, photoperiod, and nuclear genotype was significant in one or more experiments for days to anthesis and potential spikelet number, and interaction of cytoplasm, vernalization, and nuclear genotype was significant for days to spike emergence. Long day length was associated with increased percentage seed set in one study, but interactions of photoperiod and cytoplasm were not detected for percentage seed set. Interactions involving cytoplasm and photoperiod or vernalization were interpreted as evidence of the existence of genetic factors in cytoplsam of T. timopheevii which alter photoperiod or vernalization responses of alloplasmic plants relative to responses exhibited by euplasmic plants. Since photoperiod and vernalization responses are critical to adaptation, T. timopheevii cytoplasm can alter adaptability of T. aestivum. The specific effect would be nuclear genotype dependent, and does not appear to be of a magnitude greater than that induced by nuclear genetic variability at loci conditioning photoperiod or vernalization responses or other adaptation-determining characteristics. Normal multilocation/year testing of alloplasmic hybrids should therefore adequately identify zones of adaptation.
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    Rye chromosome translocations in hexaploid wheat: a re-evaluation of the loss of heterochromatin from rye chromosomes (1980)
    Springer
    Theoretical and applied genetics 56 (1980), S. 17-23 
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    ISSN: 1432-2242
    Keywords: Wheat ; Rye ; Triticale ; Highly repeated ; DNA sequences ; Heterochromatin ; Translocations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Using in situ hybridization techniques, we have been able to identify the translocated chromosomes resulting from whole arm interchanges between homoeologous chromosomes of wheat and rye. This was possible because radioactive probes are available which recognize specific sites of highly repeated sequence DNA in either rye or wheat chromosomes. The translocated chromosomes analysed in detail were found in plants from a breeding programme designed to substitute chromosome 2R of rye into commercial wheat cultivars. The distribution of rye highly repeated DNA sequences showed modified chromosomes in which (a) most of the telomeric heterochromatin of the short arm and (b) all of the telomeric heterochromatin of the long arm, had disappeared. Subsequent analyses of these chromosomes assaying for wheat highly repeated DNA sequences showed that in type (a), the entire short arm of 2R had been replaced by the short arm of wheat chromosome 2B and in (b), the long arm of 2R had been replaced by the long arm of 2B. The use of these probes has also allowed us to show that rye heterochromatin has little effect on the pairing of the translocated wheat arm to its wheat homologue during meiosis. We have also characterized the chromosomes resulting from a 1B-1R translocation event. From these results, we suggest that the observed loss of telomeric heterochromatin from rye chromosomes in wheat is commonly due to wheat-rye chromosome translocations.
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    URL: http://dx.doi.org/10.1007/BF00264422
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    Aneuploid analysis of low molecular weight gliadins from wheat (1980)
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    Theoretical and applied genetics 56 (1980), S. 65-69 
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    ISSN: 1432-2242
    Keywords: Wheat ; Gliadins ; Chromosomal control ; Aneuploid analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The chromosomal location of genes affecting five components from the low molecular weight gliadin (LMWG) fraction from wheat endosperm has been investigated by aneuploid analysis. Genes controlling these proteins were assigned to chromosomes 4B, 7A and 7D. Chromosomes from homoeologous groups 1, 2 and 6, where genes controlling classical gliadins are located, are not involved in the control of LMWG.
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    URL: http://dx.doi.org/10.1007/BF00264427
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    Genotypic effects of the maternal tissues of wheat on its grain weight (1980)
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    Theoretical and applied genetics 58 (1980), S. 247-252 
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    ISSN: 1432-2242
    Keywords: Maternal tissues ; Grain weight ; Wheat ; Triticum aestivum ; Caryopsis ; Pericarp ; Endosperm ; Embryo
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Reciprocal crosses were made between semi dwarf spring wheat cultivars (Triticum aestivum L.) differing in grain weight. The weights of the F1 grains (on maternal spikes), from intact as well as from defoliated plants, and those of the F2 grains (on f1 spikes), were examined. Grain weight was controlled primarily by the genotype of the maternal tissues (pericarp, testa or other floret or spikelet organs, including the vascular system), with complete dominance of heaviness. No indications suggesting maternal inheritance were obtained. The frequency distribution of the weights of the F2 grains indicated the presence of genotypic effects exerted by the endosperm or embryo. The embryo or endosperm factors for heaviness also seemed to be dominant.
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    URL: http://dx.doi.org/10.1007/BF00265174
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    Identification of a 4A/7R and a 7B/4R wheat-rye chromosome translocation (1981)
    Springer
    Theoretical and applied genetics 59 (1981), S. 33-37 
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    ISSN: 1432-2242
    Keywords: Wheat ; Rye ; Gene transfer ; Translocations ; Homoeologous genes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary By producing chromosome substitutions with ‘Imperial rye’ chromosomes 4R (C) and 7R (D) in the wheat cultivar ‘Chinese Spring’ two spontaneous translocation lines were obtained. One involves segments of wheat chromosome 4A and rye chromosome 7R, the other involves portions of wheat chromosome 7B and rye chromosome 4R
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    URL: http://dx.doi.org/10.1007/BF00275773
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    Chromosomal location of genes controlling seed proteins in species related to wheat (1981)
    Springer
    Theoretical and applied genetics 59 (1981), S. 25-31 
    Details
    ISSN: 1432-2242
    Keywords: Seed proteins ; Wheat ; Barley ; Rye ; Ae. umbellulata ; Ag. elongatum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The seed proteins of ‘Chinese Spring’ wheat stocks which possess single chromosomes from other plant species related to wheat have been separated by gel electrophoresis in the presence of sodium dodecyl sulphate. Marker protein bands have been detected for both arms of barley chromosome 5, chromosome E (= 1R) and B (= 2R) of rye, chromosomes A,B (= 1Cu) and C (= 5Cu) of Aegilops umbellulata and chromosomes I and III of Agropyron elongatum. These studies, and previous findings, indicate that chromosome 5 of barley, chromosome 1R of rye, chromosome I of Ag. elongatum and possibly chromosome 1Cu of Ae. umbellulata are similar to chromosomes 1A, 1B and 1D in hexaploid wheat in that they carry genes controlling prolamins on their short arms and genes controlling high-molecular-weight (apparent molecular weight greater than 86,000) seed protein species on their long arms. These findings support the idea that all these chromosomes are derived from a common ancestral chromosome and that they have maintained their integrity since their derivation from that ancestral chromosome.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00275771
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    Observed and hypothetical leaf rust progress curves of some genotypes of wheat (1981)
    Springer
    Theoretical and applied genetics 60 (1981), S. 85-88 
    Details
    ISSN: 1432-2242
    Keywords: Wheat ; Leaf rust ; Resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The hypothetical leaf rust progress curves of 15 genotypes of wheat were generated by integrating the components of slow rusting resistance determined in the glasshouse. The area under the disease progress curve (AUDPC) from the hypothetical and observed leaf rust progress curves were compared. It was found that the hypothetical AUDPC values of all the genotypes studied were smaller than their respective observed AUDPC values. Possible causes for the discrepancies in the observed and hypothetical values are discussed.
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    URL: http://dx.doi.org/10.1007/BF00282422
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    Race-specific interactions between wheat genotypes and Indian cultures of stem rust (1981)
    Springer
    Theoretical and applied genetics 60 (1981), S. 161-166 
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    ISSN: 1432-2242
    Keywords: Gene expression ; Resistance ; Local virulence ; Stem rust ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Near isogenic/substitution lines of stem rust resistance genes in different backgrounds of ‘Marquis’, ‘Chinese Spring’ and W 2691 and certain varieties with known genes for stem rust resistance were tested against each of 19 Indian cultures of stem rust races/biotypes (14, 15, 17, 21, 21A-1, 24, 34, 40, 40A, 42, 42B, 117, 117A, 117A-1, 122, 184, 194, 222 and 295). Sr 24 (‘Sear's 3D/Ag’), Sr 24 (TR 380-27 4/3 Ag 14-White seeded recombinant with ‘Agent’ type resistance), Sr 25 (‘Sear's 7D/Ag’), Sr 26 (‘Eagle’), Sr 26 (Knott's 6A/Ag translocation), Sr 27 (WRT 238-5), Combination line (Sr Tt1 + Sr 9b) were observed to be completely effective against all the 19 cultures tested. In addition, a number of lines, such as TAF2d (Sr Agi), Line W(Sr Tt2) and Combination III (Sr Tt1 + Sr 9e), were found to be effective against at least three of the most prevalent races (21, 40A and 117A-1) and a virulent race 122 in Indian natural population. Lines carrying genes other than Sr 2, Sr 9a, Sr 9f (‘Chinese Spring’) and Sr 15 (‘Norka’), and Line E were found to be resistant to one or more cultures of stem rust. The background effect upon the expression of a gene was observed by comparing the range of infection on single gene host lines in either different backgrounds and/or in cultivars with known genes for stem rust resistance against the 12 cultures of stem rust races found in India.
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    URL: http://dx.doi.org/10.1007/BF00264522
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    An analysis of genes for resistance against two Indian cultures of stem rust races of two bread wheats (1981)
    Springer
    Theoretical and applied genetics 60 (1981), S. 157-160 
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    ISSN: 1432-2242
    Keywords: Triticum aestivum ; Wheat ; Puccinia graminis ; Stem rust resistance ; Inheritance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Two bread wheat accessions, E5008 and E6160, have been genetically analysed for resistance genes effective against Indian cultures of stem rust races, 15C and 122. The inheritance of resistance to each race has been determined from the F1 and F2 of the crosses (resistant parents with the susceptible variety, ‘Agra Local’) and F2 progenies from the backcross to ‘Agra Local’. Tests have been performed to see if the two varieties carry common genes/s for resistance. The identity of the genes for resistance has been established from relevant crosses with single gene lines carrying known genes for resistance. A single dominant gene effective to race 15C in E5008 has been demonstrated to be Sr9b. Of the two recessive genes, each producing distinct infection types (0; and 1–3) against race 122, one gene has been inferred to be Sr12 and the second to be a hitherto undesignated gene. The resistance of E6160 against race 15C is controlled by two genes, one dominant and one recessive. The dominant gene has been identified as Sr9b. The recessive gene has been inferred to be a new gene. Similarly, a dominant gene effective against race 122 in E6160 has been observed to be different from those so far designated. In addition, the presence of modifier gene/s in the variety, E6160 has been suggested.
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    URL: http://dx.doi.org/10.1007/BF00264521
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    Inheritance of glutenin protein subunits of wheat (1981)
    Springer
    Theoretical and applied genetics 60 (1981), S. 333-337 
    Details
    ISSN: 1432-2242
    Keywords: Wheat ; Seed proteins ; Glutenin protein ; subunits
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The inheritance of the high-molecular-weight (HMW) glutenin protein subunits in hexaploid wheat has been investigated by using sodium dodecyl sulphate-polyacrylamide gel electrophoresis to examine the segregation of these subunits in 496 test-cross seeds. The parents of the f1 hybrid were chosen so that the test-cross seeds segregated for all the HMW glutenin bands. Two glutenin subunits from one parent, believed to be controlled by genes on chromosome 1D, segregated as alternatives to two glutenin subunits from the other parent, a result that supports the assumption that these subunits are controlled by allelic genes at each of two loci that are very closely linked. Similar results were obtained for glutenin subunits believed to be controlled by chromosome IB, which suggests that these subunits are controlled also by allelic genes at each of two loci that are very closely linked. A single glutenin subunit band, believed to be controlled by chromosome 1A, segregated as an alternative to a single glutenin band from the other parent, except that one seed did not possess either band. It was concluded that these bands are controlled either by allelic genes or by nonallelic genes that are very closely linked.
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    URL: http://dx.doi.org/10.1007/BF00264323
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    Two NAD-dependent alcohol dehydrogenases (E.C. 1.1.1.1) in callus cultures of wheat, rye and triticale (1982)
    Springer
    Theoretical and applied genetics 62 (1982), S. 45-48 
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    ISSN: 1432-2242
    Keywords: Wheat ; Rye ; Triticale ; Callus cultures ; Alcohol dehydrogenase ; Isoenzymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Two NAD-dependent alcohol dehydrogenases ADH-1 and ADH-2, under independent genetic control of genes designated as Adh-1 and Adh-2 located on chromosomes 4A, 4B and 4D, have been reported in aestivum wheat (Hart 1980). Only ADH-1 is expressed in developing seeds, dry seeds, pollen and germinating seedlings. ADH-2 can be induced in seedling roots or shoots under conditions of partial anaerobiosis or by certain chemicals. Expression of ADH-1 and ADH-2 isoenzymes was investigated in undifferentiated calli from aestivum and durum wheats, rye, triticale and also in in vitro regenerated roots and leaves from aestivum cultures. Wheat callus cultures originating from seed, mature and immature embryos, mesocotyl and root, as well as cultures grown on media containing different supplements did not show any variation in the overall expression of ADH-1 or ADH-2, although differences in the band intensities were observed. The callus isoenzyme pattern was similar to that observed in roots under anaerobic conditions. Both ADH-1 and ADH-2 were expressed in in vitro regenerated roots but were absent in regenerated leaves. Expression of ADH-1 and ADH-2 in wheat calli seems to be related to the type of differentiation.
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    URL: http://dx.doi.org/10.1007/BF00276281
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    Predicting the frequencies of transgressive segregants for yield and yield components in wheat (1982)
    Springer
    Theoretical and applied genetics 62 (1982), S. 127-134 
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    ISSN: 1432-2242
    Keywords: Wheat ; Genetical analysis ; Cross prediction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Genetical analysis of the F2 triple test cross design combined with conventional early generations was used to elucidate the genetical control of yield and yield components in two crosses of winter wheat. From estimates of the additive, {d}, and additive X additive, {i}, components of means, together with the additive genetical variance, D, predicted frequencies of recombinant inbred lines that would transgress the parental range were calculated for each cross. The accuracy of predictions was evaluated by comparing expected frequencies with observed numbers in populations of F6 lines previously developed by single seed descent. For both crosses and all characters where an adequate genetical model was found to explain the observed variation between the early generations, good agreement between predicted and observed frequencies of transgressive segregants was obtained. Furthermore, for characters exhibiting significant epistasis, allowance for additive X additive {i} epistasis in the prediction equations was sufficient to allow for skewness of the recombinant inbred population. These results demonstrate that cross performance in wheat can be predicted from genetical analysis of early generations, and the value of this approach in breeding new varieties is discussed.
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    URL: http://dx.doi.org/10.1007/BF00293344
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    The Tom Thumb dwarfing gene, Rht3 in wheat, I. Reduced pre-harvest damage to breadmaking quality (1982)
    Springer
    Theoretical and applied genetics 62 (1982), S. 121-126 
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    ISSN: 1432-2242
    Keywords: Wheat ; Quality ; Dwarfism ; Gibberellin ; α-amylase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The effects of the Tom Thumb dwarfing gene, Rht3, on the quality and quantity of grain α-amylase produced during germination and by induction with exogenous gibberellic acid are described. In a season conducive to high sprouting damage the gene reduced α-amylase levels in the field by 77%. Selection among random Rht3 genotypes showed that other genetic factors can be combined with the dwarfing gene to further increase sprouting damage resistance.
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    URL: http://dx.doi.org/10.1007/BF00293343
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    Genetic control of 6-phosphogluconate dehydrogenase (6-PGD) isozymes in cultivated wheat and rye (1982)
    Springer
    Theoretical and applied genetics 62 (1982), S. 317-320 
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    ISSN: 1432-2242
    Keywords: Wheat ; Rye ; Phosphogluconate dehydrogenase ; Genetic control
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The 6-phosphogluconate dehydrogenase (6-PGD) zymogram phenotypes of wheat, rye and their aneuploid derivatives were determined. Two genes involved in the production of 6-PGD isozymes were located on chromosome arms CRL (4 RL) and FRL (6 RL) of “Imperial” rye. On the basis of differential interactions between wheat and rye chromosomes, evidence was obtained that genes located on chromosomes 6 A, 6 BL and 7 BL control 6-PGD isozyme activities in ‘Chinese Spring’ wheat. The wheat and rye 6-PGD zymogram phenotypes were indicative of homoeologous relationships between rye chromosome 6 RL to wheat chromosomes of group 6, and rye chromosome 4 RL to wheat chromosomes of group 7.
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    URL: http://dx.doi.org/10.1007/BF00275094
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    The purification and characterization of homologous high molecular weight storage proteins from grain of wheat, rye and barley (1982)
    Springer
    Theoretical and applied genetics 62 (1982), S. 329-336 
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    ISSN: 1432-2242
    Keywords: HMW storage prolamins ; Wheat ; Rye ; Barley ; Characterization and purification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Homologous high molecular weight storage prolamins were purified from grain of wheat, rye and barley using combinations of gel filtration, ion-exchange chromatography and preparative isoelectric focusing. Sodium dodecylsulphate polyacrylamide gel electrophoresis showed that the components were single bands with apparent mol.wts. of above 100,000. Molecular weights determined by sedimentation equilibrium ultracentrifugation were considerably lower; 54,700, 67,600 and 69,600 for the components from barley, rye and wheat respectively. Amino acid analysis showed the presence of 13.6 to 16.5 mol% glycine, 29.6 to 34.0 mol% glutamate + glutamine, 11.4 to 13.7 mol% proline and a total of 4.0 to 5.7 mol% basic amino acids. Automated N-terminal amino acid sequencing of the component from wheat showed the presence of cysteine residues at positions 5 and 10, and this is discussed in relation to the possible role of these proteins in the visco-elastic gluten network.
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    URL: http://dx.doi.org/10.1007/BF00275097
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    C-banded wheat chromosomes in wheat and triticale (1982)
    Springer
    Theoretical and applied genetics 63 (1982), S. 39-47 
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    ISSN: 1432-2242
    Keywords: C-banding ; Wheat ; Triticale ; Heterochromatin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The C-banding patterns of wheat chromosomes in 7 hexaploid triticale and 7 wheat genotypes are described and compared. All 14 wheat chromosome pairs were individually identified in the triticales and a tetraploid wheat, and all the B and two A genome chromosome pairs in the hexaploid wheat genotypes. Little variation was found between genotypes in the distribution of C-bands but considerable variation was found in their size, total number and total length.
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    URL: http://dx.doi.org/10.1007/BF00303488
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    Relationships of Agropyron intermedium chromosomes determined by chromosome pairing and alcohol dehydrogenase isozymes in common wheat background (1982)
    Springer
    Theoretical and applied genetics 63 (1982), S. 213-217 
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    ISSN: 1432-2242
    Keywords: Wheat ; Agropyron ; Chromosome pairing ; Alcohol dehydrogenase isozymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The relationships of Agropyron intermedium chromosomes in two wheat-Agropyron addition series were determined. Chromosome pairing behaviour revealed that the alien chromosome in lines TAF-2 and L7 of ‘Vilmorin’-A. intermedium set are homologous to the alien chromosomes in lines P and C of the ‘Caribo’-A. intermedium set respectively. Localization of alcohol dehydrogenase isozyme genes in ‘Vilmorin’-Agropyron addition line L4 and in ‘Caribo’-Agropyron line O indicated relationships with wheat chromosomes of homoeologous group 4.
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    URL: http://dx.doi.org/10.1007/BF00303996
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    The wheat ribosomal DNA spacer region: Its structure and variation in populations and among species (1982)
    Springer
    Theoretical and applied genetics 63 (1982), S. 337-348 
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    ISSN: 1432-2242
    Keywords: Wheat ; rDNA ; Sequence ; Populations ; Variation ; Spacer region ; Triticum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The wheat rDNA clone pTA250 was examined in detail to provide a restriction enzyme map and the nucleotide sequence of two of the eleven, 130 bp repeating units found within the spacer region. The 130 bp units showed some sequence heterogeneity. The sequence difference between the two 130 bp units analysed (130.6 and 130.8) was at 7 positions and could be detected as a 4 °C shift in Tm when heterologous and homologous hybrids were compared. This corresponded to a 1.2% change in nucleotide sequence per ΔTm of 1 °C. The sensitivity of the Tm analysis using cloned sequences facilitated the analysis of small sequence variations in the spacer region of different Triticum aestivum cultivars and natural populations of T. turgidum ssp. dicoccoides (referred to as T. dicoccoides). In addition spacer length variation was assayed by restriction enzyme digestion and hybridization with spacer sequence probes. Extensive polymorphism was observed for the spacer region in various cultivars of T. aestivum, although within each cultivar the rDNA clusters were homogeneous and could be assigned to particular chromosomes. Within natural populations of T. dicoccoides polymorphism was also observed but, once again, within any one individual the rDNA clusters appeared to be homogeneous. The polymorphism, at the sequence level (assayed by Tm analysis), was not so great as to prevent the use of spacer sequence variation as a probe for evolutionary relationships. The length variation as assayed by restriction enzyme digestion did not appear to be as useful in this regard, since its range of variation was extensive even within populations of a species.
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    URL: http://dx.doi.org/10.1007/BF00303905
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    Chromosome and nucleotide sequence differentiation in genomes of polyploid Triticum species (1982)
    Springer
    Theoretical and applied genetics 63 (1982), S. 349-360 
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    ISSN: 1432-2242
    Keywords: Chromosomes ; Nucleotides ; Evolution ; Polyploids ; Triticum ; Heterochromatin ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The nature of genome change during polyploid evolution was studied by analysing selected species within the tribe Triticeae. The levels of genome changes examined included structural alterations (translocations, inversions), heterochromatinization, and nucleotide sequence change in the rDNA regions. These analyses provided data for evaluating models of genome evolution in polyploids in the genus Triticum, postulated on the basis of chromosome pairing at metaphase I in interspecies hybrids. The significance of structural chromosome alterations with respect to reduced MI chromosome pairing in interspecific hybrids was assayed by determining the incidence of heterozygosity for translocations and paracentric inversions in the A and B genomes of T. timopheevii ssp. araraticum (referred to as T. araraticum) represented by two lines, 1760 and 2541, and T. aestivum cv. Chinese Spring. Line 1760 differed from Chinese Spring by translocations in chromosomes 1A, 3A, 4A, 6A, 7A, 3B, 4B, 7B and possibly 2B. Line 2541 differed from Chinese Spring by translocations in chromosomes 3A, 6A, 6B and possibly 2B. Line 1760 also differed from Chinese Spring by paracentric inversions in arms 1AL and 4AL whereas line 2541 differed by inversions in 1BL and 4AL (not all chromosomes arms were assayed). The incidence of structural changes in the A and B genomes did not coincide with the more extensive differentiation of the B genomes relative to the A genomes as reflected by chromosome pairing studies. To assay changing degrees of heterochromatinization among species of the genus Triticum, all the diploid and polyploid species were C-banded. No general agreement was observed between the amount of heterochromatin and the ability of the respective chromosomes to pair with chromosomes of the ancestral species. Marked changes in the amount of heterochromatin were found to have occurred during the evolution of some of the polyploids. The analysis of the rDNA region provided evidence for rapid “fixation” of new repeated sequences at two levels, namely, among the 130 bp repeated sequences of the spacer and at the level of the repeated arrays of the 9 kb rDNA units. These occurred both within a given rDNA region and between rDNA regions on nonhomologous chromosomes. The levels of change in the rDNA regions provided good precedent for expecting extensive nucleotide sequence changes associated with differentiation of Triticum genomes and these processes are argued to be the principal cause of genome differentiation as revealed by chromosome pairing studies.
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    URL: http://dx.doi.org/10.1007/BF00303906
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    Chloroplast DNA and cytoplasmic male-sterility (1983)
    Springer
    Theoretical and applied genetics 64 (1983), S. 231-238 
    Details
    ISSN: 1432-2242
    Keywords: Maize ; Wheat ; Rape ; Restriction fragments ; Two dimensional electrophoresis ; Melting profiles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary This paper deals with the relationship of chloroplast DNA (ctDNA) and cytoplasmic malesterility (CMS) of maize, wheat and rape. Intramolecular heterogeneity and fragment patterns of DNA digested with restriction endonucleases were compared and analyzed. For this purpose methods of agarose gel electrophoresis and two dimensional gel electrophoresis with denaturating solvent concentration gradients were applied. 1) Heat denaturation of ctDNA from a male sterile line in maize yielded a profile with three melting regions. This base sequence heterogeneity was not observed for the ctDNA of its maintainer. 2) Maize ctDNA was digested with EcoR1 and BamH1 restriction endonucleases, wheat and rape ctDNA with EcoR1 only. No significant differences were observed in the comparison of the fragment patterns from the sterile lines and their maintainers with the exception of the sterile line in rape which lacked one fragment present in its maintainer. 3) Two dimensional electrophoresis using a gradient of denaturing agents revealed several differences in number and relative positions of the separated restriction endonuclease fragments between the sterile lines and their respective maintainers in all three tested crops. This raises the possibility that changes in ctDNA may be involved in CMS.
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    URL: http://dx.doi.org/10.1007/BF00303770
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    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.
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    URL: http://dx.doi.org/10.1007/BF00226972
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    Electron-dense precipitates in glomus cells of rat carotid body after fixation in glutaraldehyde and pyroantimonate-osmium tetroxide mixture as possible indicators of calcium localization (1981)
    Springer
    Cell & tissue research 217 (1981), S. 93-104 
    Details
    ISSN: 1432-0878
    Keywords: Carotid body ; Calcium ; Granular vesicles ; Exocytosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An attempt was made to study the subcellular localization of calcium in carotid body glomus cells of adult rats using fixation with glutaraldehyde followed by treatment with a mixture of pyroantimonate and osmium tetroxide. Precipitates were seen as electron-dense particles (EDP) in the glomus cells, mostly within membrane-bound organelles, such as dense-cored vesicles, mitochondria, small clear vesicles, multivesicular bodies, and especially in lysosomes. However, EDP were also seen in the nuclei and in the free cytoplasm of the glomus cells and even outside them. Preincubation of carotid bodies in media containing calcium and either high potassium or calcium-ionophore A 23187 resulted in a marked increase in the general precipitation pattern, there being an increased amount of EDP both in the glomus cell nuclei and in the cytoplasm. Dense-cored vesicles more often showed precipitates than those in the controls. Some dense-cored vesicles contained multiple precipitates, typically located in the electron-lucent area between core and vesicle membrane. Extensive diffusion of ions probably occurred during fixation before precipitation, making the localization of calcium and other precipitating cations unreliable. However, it is possible that precipitates, which were regularly seen in the dense-cored vesicles, may reflect the content of bound calcium. The possible significance of calcium in glomus cell function is discussed, and the need for more adequate methods is emphasized.
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    URL: http://dx.doi.org/10.1007/BF00233829
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    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.
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    URL: http://dx.doi.org/10.1007/BF00216536
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    Disruption of insect photoreceptor membrane by divalent ions: Dissimilar sensitivity of light- and dark-adapted mosquito rhabdomeres (1981)
    Springer
    Cell & tissue research 216 (1981), S. 403-411 
    Details
    ISSN: 1432-0878
    Keywords: Photoreceptors ; Calcium ; Fixation artifact ; Light-adaptation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The conditions that lead to the formation of myelin figures in rhabdomere microvilli were studied in the larval ocelli of the mosquito Aedes aegypti. These artifacts can result from the addition of divalent ions, such as Ca2+, to primary-aldehyde fixatives, but they form subsequently during postfixation with OsO4. In light-adapted ocelli, myelin figures are concentrated at the proximal ends of the microvilli along the cytoplasmic margin of the rhabdomere. The severity of the artifact is proportional to the ion concentration: scattered myelin whorls are induced by Ca2+ concentrations as low as 5 mM; they become abundant at 15 mM to 25 mM, and displace much of the rhabdomere margin at 50 mM. In contrast, even at high concentrations of Ca2+ few membrane whorls form in dark-adapted rhabdomeres, and these are mostly located at the distal ends of the microvilli. The differential response of the rhabdomere microvilli in light and darkness does not result from a direct action of light during fixation; it reflects an underlying difference between light- and dark-adapted photoreceptor membranes. We suggest that this differential sensitivity to divalent ions is associated with the shedding of membranes from the rhabdomere, a process that is enhanced by light and reduced in darkness.
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    URL: http://dx.doi.org/10.1007/BF00233627
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    PAS-positive cells of the pars intermedia are calcium-sensitive in the goldfish maintained in a hyposmotic milieu (1980)
    Springer
    Cell & tissue research 212 (1980), S. 29-38 
    Details
    ISSN: 1432-0878
    Keywords: Pituitary ; Pars intermedia ; Calcium ; Deionized water ; Teleosts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Cytological changes in the pars intermedia of the goldfish were investigated after adding calcium to deionized water (DW). In fish maintained in DW, the PAS-positive cells are highly stimulated in comparison to cells of fish kept in fresh water (FW). In DW supplemented with calcium at the same concentration as in FW (2 mM/l), the hyperactivity of the PAS-positive cells is prevented. When calcium ions are added 60 h before the animals are sacrificed, the PAS positive cells start to show signs of regression and their granules are stored: the release of the granular material appears to be suppressed by calcium. In the goldfish, the PAS-positive cells, homologous to a similar cell type in the eel, react only very weakly with the PAS technique. The name “calcium-sensitive cells” appears to be more appropriate in the goldfish for this particular cell type, secreting an unknown factor. This factor, different from the prolactin produced in the rostral pars distalis of the hypophysis, might be an equivalent of a “hypercalcin”.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234030
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  • 96
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    Pinocytosis and locomotion of amoebae (1980)
    Springer
    Cell & tissue research 213 (1980), S. 9-20 
    Details
    ISSN: 1432-0878
    Keywords: Pinocytosis ; Calcium ; Chlorotetracycline ; Fluorescence microscopy ; Amoeba proteus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The dynamics of Ca++ during induced pinocytosis were studied in Amoeba proteus using chlorotetracycline (CTC). The fluorescence of the Ca++ -CTC-complex was monitored by an image intensification system, which has certain advantages over standard equipment: (1) Living cells are not subjected to the damaging influence of intensive microscopic illumination, (2) fluorescent probes are not bleached during observation, and (3) the rapid dynamics of Ca++-fluxes can be recorded using short exposure times. The results demonstrate the existence of Ca++ bound to intracellular and extracellular sites of the cell membrane complex in normal locomoting and pinocytoting Amoeba proteus. The application of cations inducing pinocytosis causes a rapid decrease in the external CTC-fluorescence probably due to a release of Ca++ from the mucous layer. The degree of fluorescence intensity is correlated with the capacity of pinocytotic channel formation, i.e., the fluorescence decreases as the number of channels increases. During the phase of vesiculation a distinct fluorescence mainly restricted to the basal region of the channels is observed. Intracellular Ca++ was detected in close vicinity to the plasma membrane after both microinjection and external application of CTC. The internal CTC-fluorescence is slightly decreased during the induction phase of pinocytosis. The observations are in good agreement with previous results on the localization of Ca++-binding sites at the plasma membrane of Amoeba proteus and demonstrate the important role of Ca++-fluxes for the process of pinocytosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236916
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  • 97
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    The development of the wheat embryo in relation to the neighbouring tissues (1983)
    Springer
    Protoplasma 114 (1983), S. 1-13 
    Details
    ISSN: 1615-6102
    Keywords: Embryo ; Endosperm ; Scutellum ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The overall morphology of the developing wheat embryo in relation to its neighbouring tissues is described. The embryo is “isolated” early in development, but appears to be a powerful sink for nutrients. It is supplied initially by hydrolysis of the nucellar parenchyma and later by hydrolysis of neighbouring endosperm cells, which are completely digested. Later on, the nucellar epidermis forms specialised cells that may be transfer cells opposite the groove at the base of the embryo. The accumulation of starch and protein appears to begin first in the basal tissues of the scutellum and coleorhiza.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01279863
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  • 98
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    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
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  • 99
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    Callus induction and growth from the mature embryo ofTriticum aestivum (Wheat) (1983)
    Springer
    Protoplasma 115 (1983), S. 104-113 
    Details
    ISSN: 1615-6102
    Keywords: Cereals ; Embryo culture ; Triticum aestivum ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Cell proliferation from the mature embryo of wheat occurs on a defined medium in the presence of 2,4-D. Unorganized growth is observed when the 2,4-D concentration is equal to or greater than 2 mg/l, but increasing levels of 2,4-D inhibit cell division. Cell divisions begin after 4 days in culture from parenchyma cells within and near the procambial tissues of the embryo axis. By day 8 continuous meristematic zones are formed in association with vascular tissues, and DNA synthesis and cell divisions are distributed throughout these zones. No morphological evidence exists to show that these zones consist of proliferating root primordia, which are formed only after the level of 2,4-D falls below some critical concentration. When the concentration of 2,4-D is lowered, the meristematic zones first become dissected and then give rise to many root meristems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01279802
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  • 100
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    Improved efficiency and normalization of somatic embryogenesis inTriticum aestivum (wheat) (1983)
    Springer
    Protoplasma 117 (1983), S. 40-44 
    Details
    ISSN: 1615-6102
    Keywords: Cereals ; Immature embryo ; Somatic embryogenesis ; Tissue culture ; Triticum aestivum L. ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Tissue cultures derived from the scutellum of immature embryos ofTriticum aestivum L. (wheat) gave rise to somatic embryos with a well-defined scutellum and coleoptile as well as one or more shoot primordia and a root primordium. The normal somatic embryos were formed from compact, white callus tissue which was not observed until 4 or more weeks after culture initiation. The highest frequency of white embryogenic tissue formation and the most normal embryoids were obtained in the dark on Murashige and Skoog's medium with twice the concentration of inorganic salts plus sucrose (2%), inositol (100–200 mg/l), casein hydrolysate (100–200 mg/l), glutamine (500 mg/l), and 2,4-dichlorophenoxyacetic acid (1–2 mg/l).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01281782
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