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  • Articles  (356)
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  • 1980-1984  (227)
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  • 1984  (100)
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  • Articles  (356)
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  • 1980-1984  (227)
  • 1970-1974  (129)
  • 1925-1929
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  • 1
    Electronic Resource
    Electronic Resource
    Corticotropin releasing factor increases the adrenocortical responsiveness to adrenocorticotropin (1984)
    Springer
    Cellular and molecular life sciences 40 (1984), S. 1004-1006 
    Details
    ISSN: 1420-9071
    Keywords: Rat ; adrenocortical responsiveness ; ACTH ; plasma ; corticosterone ; plasma ; corticotropin releasing factor (CRF)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the course of studying the plasma adrenocorticotropic hormone (ACTH) and corticosterone responses to synthetic corticotropin releasing factor (CRF), we noted some disparity in the responses. A higher dose (20 μg compared with 5 μg per rat i.a.) produced an equal plasma ACTH but greater plasma corticosterone response in adult male rats. Thus, we examined the possibility that CRF increases adrenocortical responsiveness to ACTH. CRF significantly (p〈0.0005) increased the plasma corticosterone response to ACTH in rats pretreated with dexamethasone. Thus, synthetic CRF increases corticosterone secretion in rats not only by stimulating ACTH secretion, but also by increasing the adrenocortical responsiveness to ACTH.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01946481
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  • 2
    Electronic Resource
    Electronic Resource
    Do prostaglandins mediate the somatostatin preventive effect on gastric lesion? (1984)
    Springer
    Cellular and molecular life sciences 40 (1984), S. 974-975 
    Details
    ISSN: 1420-9071
    Keywords: Rat ; prostaglandins ; gastric lesion ; intragastric distension model ; stress model ; indomethacin ; somatostatin preventive effect
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The inhibition of endogenous prostaglandin synthesis by indomethacin treatment blocks the somatostatin preventive effect on the gastric lesions induced in a stress model and has no preventive effect on an intragastric distension model.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01946466
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  • 3
    Electronic Resource
    Electronic Resource
    Adjacent chromosomal regions can evolve at very different rates: Evolution of theDrosophila 68C glue gene cluster (1984)
    Springer
    Journal of molecular evolution 20 (1984), S. 251-264 
    Details
    ISSN: 1432-1432
    Keywords: Drosophila ; Genome evolution ; 68C Glue gene cluster ; Drosophila melanogaster species subgroup
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The 68C puff is a highly transcribed region of theDrosophila melanogaster salivary gland polytene chromosomes. Three different classes of messenger RNA originate in a 5000-bp region in the puff; each class is translated to one of the salivary gland glue proteins sgs-3, sgs-7, or sgs-8. These messenger RNA classes are coordinately controlled, with each RNA appearing in the third larval instar and disappearing at the time of puparium formation. Their disappearance is initiated by the action of the steroid hormone ecdysterone. In the work reported here, we studied evolution of this hormone-regulated gene cluster in themelanogaster species subgroup ofDrosophila. Genome blot hybridization experiments showed that five other species of this subgroup have DNA sequences that hybridize toD. melanogaster 68C sequences, and that these sequences are divided into a highly conserved region, which does not contain the glue genes, and an extraordinarily diverged region, which does. Molecular cloning of this DNA fromD. simulans, D. erecta, D. yakuba, andD. teissieri confirmed the division of the region into a slowly and a rapidly evolving protion, and also showed that the rapidly evolving region of each species codes for third instar larval salivary gland RNAs homologous to theD. melanogaster glue mRNAs. The highly conserved region is at least 13,000 bp long, and is not known to code for any RNAs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02104731
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  • 4
    Electronic Resource
    Electronic Resource
    Mutations affecting the pattern of the larval cuticle inDrosophila melanogaster (1984)
    Springer
    Development genes and evolution 193 (1984), S. 267-282 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Larval cuticle ; Pattern formation ; Embryonic lethal mutations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In a search for embryonic lethal mutants on the second chromosome ofDrosophila melanogaster, 5764 balanced lines isogenic for an ethyl methane sulfonate (EMS)-treatedcn bw sp chromosome were established. Of these lines, 4217 carried one or more newly induced lethal mutations corresponding to a total of 7600 lethal hits. Eggs were collected from lethal-bearing lines and unhatched embryos from the lines in which 25% or more of the embryos did not hatch (2843 lines) were dechorionated, fixed, cleared and scored under the compound microscope for abnormalities of the larval cuticle. A total of 272 mutants were isolated with phenotypes unequivocally distinguishable from wild-type embryos on the basis of the cuticular pattern. In complementation tests performed between mutants with similar phenotype, 48 loci were identified by more than one allele, the average being 5.4 alleles per locus. Complementation of all other mutants was shown by 13 mutants. Members of the complementation groups were mapped by recombination analysis. No clustering of loci with similar phenotypes was apparent. From the distribution of the allele frequencies and the rate of discovery of new loci, it was estimated that the 61 loci represent the majority of embryonic lethal loci on the second chromosome yielding phenotypes recognizable in the larval cuticle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848156
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  • 5
    Electronic Resource
    Electronic Resource
    Isolation and characterization of temperature-sensitivelethal (2) giant larva alleles (1984)
    Springer
    Development genes and evolution 193 (1984), S. 90-97 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Temperature-sensitive ; Neoplasms ; Differentiation ; Imaginal discs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary EMS induced temperature-sensitivelethal (2) giant larva, 1(2)gl, alleles were isolated by screening against a knownl(2)gl allele. Analysis of the lethal phase of thel(2)gl ts-deficiency heterozygotes demonstrated: (1) the majority of thel(2)gl tslarvae survive to late third instar, (2) at 29°C the majority of thel(2)gl tslarvae failed to pupate and only rarely did they differentiate adult cuticular structures, (3) at 15°C the majority of the larvae pupated and frequently differentiated adult cuticular structures. Examination of the imaginal discs ofl(2)gl tslarvae reared at 29°C revealed the presence of morphologically abnormal wing, haltere and leg imaginal discs. No morphologically abnormal discs were found in thel(2)gl tslarvae reared at 15°C. Studies on both the histology and the developmental capacity of the morphologically normal and abnormall(2)gl tsdiscs were performed. The morphologically normal discs are histologically normal and produce a full complement of adult cuticular structures. However, the morphologically abnormal discs contained both regions that maintained the normal monolayer epithelium and regions that had lost the normal tissue architecture. The implants obtained when the morphologically abnormal discs are injected into metamorphosing larvae contained only a limited number of the normal complement of adult structures and usually only structures found in the ventral wing hinge region were recovered. In addition, the “metamorphosed” morphologically abnormal discs contained undifferentiated tissue that gave rise to transplantable neoplasms when cultured in adults. The results of the studies on the pathology of thel(2)gl tslarvae are discussed with respect to the role of thel(2)gl tsfunction during normal development, the autonomy of the neoplastic development of thel(2)gl tstissues, and similarities between neoplastic development inDrosophila and mammals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848636
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  • 6
    Electronic Resource
    Electronic Resource
    Heterospecific combinations of germ cells and gonadal soma betweenDrosophila melanogaster, D. mauritiana andD. ananassae (1984)
    Springer
    Development genes and evolution 194 (1984), S. 99-106 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Pole cell transplantation ; Heterospecific combinations ; Gametogenesis ; Chorion morphology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We transplanted pole cells betweenDrosophila melanogaster, D. mauritiana andD. ananassae to investigate the ability of germ cells to develop in the gonad of a heterospecific host, and to study the interaction between somatic follicle cells and the cells of the germ line in producing the species-specific chorion. FemaleD. mauritiana germ cells in aD. melanogaster ovary produced functional eggs with normal development potential. The same is true for the reciprocal combination. FemaleD. ananassae pole cells in aD. melanogaster host only developed to a very early stage and degenerated afterwards. None of the interspecific combinations of male pole cells led to functional sperm. We could not determine at what stage the transplanted male pole cells were arrested. The cooperation of follicle cells and the oocyte-nurse cell complex in producing the chorion was studied using the germ-line-dependent mutationfs(1) K10 ofD. melanogaster, which causes fused respiratory appendages and an abnormal chorion morphology. Wild-type femaleD. mauritiana germ cells in a mutantfs(1) K10 D. melanogaster ovary led to the production of wild-type eggs withD. melanogaster-specific, short respiratory appendages. On the other hand,D. melanogaster fs(1) K10 germ cells in aD. mauritiana ovary induced the formation of eggs with mutant fused appendages which were, however, typicallyD. mauritiana in length. When.D. mauritiana pole cells developed in aD. melanogaster ovary, the chorion exhibited a new imprint pattern that differs from both species-specific patterns.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848349
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  • 7
    Electronic Resource
    Electronic Resource
    Intracerebroventricular injection of cerebrospinal fluid (CSF) from a patient with congenital indifference to pain induces analgesia in rats (1984)
    Springer
    Cellular and molecular life sciences 40 (1984), S. 1365-1366 
    Details
    ISSN: 1420-9071
    Keywords: Rat ; cerebrospinal fluid, human ; analgesia ; naloxone ; pain indifference, congenital ; opiates, endogenous
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary CSF from a patient with congential indifference to pain was found to produce analgesia in the rat following intracerebroventricular injections. The analgesic effect was attenuated by pretreatment with naloxone suggesting the involvement of hyperactive endogenous opiate mechanisms in this patient.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01951891
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  • 8
    Electronic Resource
    Electronic Resource
    15-Hydroxyprostaglandin dehydrogenase and hexokinase in spontaneously hypertensive rat kidney (1984)
    Springer
    Cellular and molecular life sciences 40 (1984), S. 1368-1369 
    Details
    ISSN: 1420-9071
    Keywords: Rat ; kidney ; hypertensive ; prostaglandin dehydrogenase ; hexokinase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 15-Hydroxyprostaglandin dehydrogenase (PGDH) surged in hypertensive (SHR) and normotensive (WKY) rat kidney at 8 days of age, is greatest in SHR. Hexokinase fell in SHR at 17 days of age, but thereafter was similar to WKY. This suggests multisystem enzymatic abnormalities in SHR kidney during development of hypertension.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01951893
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  • 9
    Electronic Resource
    Electronic Resource
    Isolation and characterization of temperature-sensitivelethal(2)giant larva alleles (1984)
    Springer
    Development genes and evolution 193 (1984), S. 98-107 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Neoplasms ; Promotion ; Regeneration ; Temperature-sensitive ; Imaginal discs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In this paper we present an analysis of the behavior ofl(2)gl tsimaginal wing discs during culture in adult hosts. Thel(2)gl tslarvae reared at 29° C contain two types of wing discs, those that are morphologically normal and those that are abnormal. When discs of both types are cultured in adult hosts at 29° C, the restrictive temperature, they give rise to transplantable neoplastic tissue. However, when the 29° C reared discs are cultured at 15° C, the permissive temperature, the morphologically normal discs maintain their morphology, but the morphologically abnormal discs give rise to neoplasms. Thel(2)gl tslarvae reared at 15° C contain only morphologically normal discs. When these discs are cultured in adult hosts at 29° C they give rise to neoplasms, however if the discs are cultured at 15° C they maintain their normal morphology. These results demonstrate: (1) that all wing imaginal discs obtained from 29° C rearedl(2)gl tslarvae are competent to undergo neoplastic development, (2) the morphologically abnormal discs obtained from the 29° C rearedl(2)gl tslarvae are committed to neoplastic development, (3) the neoplastic development of the morphologically normal discs is temperature dependent, (4) once the neoplastic development of thel(2)gl tsdiscs has been initiated the process is not readily reversible. In addition, the ability ofl(2)gl tswing discs to perform epimorphic regulation was tested by amputating morphologically normal permissively rearedl(2)gl tswing discs and culturing both fragiments at the permissive temperature. Fragments of control wild-type discs maintained their morphology during culture at the permissive temperature. However, both fragments of txel(2)gl tsdiscs became neoplastic. This result is discussed with respect to a possible role for thel(2)gl +function in epimorphic regulation and with respect to the phenomena of tumor promotion in vertebrates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848637
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  • 10
    Electronic Resource
    Electronic Resource
    Changes in the distribution of gap junctions inDrosophila melanogaster wing discs during the third larval and early pupal stages of development (1984)
    Springer
    Development genes and evolution 193 (1984), S. 187-196 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Gap junction ; Imaginal disc ; Pattern formation ; EM Stereology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Developmental changes in the distribution of gap junctions in early, mid and late third larval stage wing discs and in pupariation+6 h and pupariation+24 h stage wing discs fromDrosophila melanogaster were analyzed by quantitative electron microscopy. Gap junctions occur in all 12 intradisc regions examined in each of the five developmental stages. Their distribution is non-random and changes during development which suggests that they are developmentally regulated. The gap junctions are not static structures, rather they grow and regress during development. The changes tend to be gradual ones without sudden increases or decreases. Gap junctions continuously form and grow in size throughout the third larval stage and during the first 6 h following pupariation. Their surface density, number, percent of the lateral plasma membrane area, and absolute area as well as the lateral plasma membrane surface density all increase during this time. Between pupariation+ 6 h and pupariation+24 h all but one of these parameters decrease indicative of gap junctional breakdown. Gap junctions are most numerous and change least during development in the apical cell regions where intercellular contacts are close and stable. They change most in the basal cell regions where intercellular contacts tend to be looser and change during development. The most dramatic change is in the absolute area which increases by a factor of 23 between the early third larval stage and pupariation+24 h. At pupariation the rate of gap junction growth undergoes a transient increase before the phase of disassembly begins. Developmental changes in gap junction surface density are closely coupled with changes in the lateral plasma membrane surface density which suggests that these may be coregulated. Evidence from mutants suggests that when the number and density of gap junctions fail to increase in proportion to lateral plasma membrane growth, wing disc development will be abnormal. Our results support the idea that some minimum gap junction density is required for normal development and that this must increase as development proceeds. The results are consistent with the notion that gap junctions are involved in pattern formation and growth control and are discussed with respect to the acquisition of competence for metamorphosis, disc growth, disc morphogenesis and changes in the hormonal environment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01260338
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  • 11
    Electronic Resource
    Electronic Resource
    Mutations affecting the pattern of the larval cuticle inDrosophila melanogaster (1984)
    Springer
    Development genes and evolution 193 (1984), S. 296-307 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Larval cuticle ; Pattern formation ; Embryonic lethal mutations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In order to identify X-chromosomal genes required inDrosophila for early patterning and morphogenesis, we examined embryos hemizygous for EMS-induced lethal mutations to determine which of those mutations cause gross morphological defects. Embryos from 2711 lethal lines, corresponding to 3255 lethal point mutations were studied. Only 21% caused death during embryogenesis and of these, only one-sixth, or 3% of the total lethals, were associated with defects visible in the final cuticle pattern. Of the 114 point mutants causing visible cuticle defects, 76 could be assigned to 14 complementation groups. An additional 25 mutations mapping to regions of the X-chromosome not covered by male fertile duplications were assigned to six complementation groups based on similarities of map position and phenotype. Thirteen mutations could not be assigned to complementation groups. All mutations allowed normal development through the cellular blastoderm stage, the first defects associated with the earliest acting loci being observed shortly after the onset of gastrulation. The phenotypes of the various loci range from alterations in segment pattern or early morphogenetic movements to defects in final pigmentation and denticle morphology. Cuticle preparations were also examined for 63 deletions spanning in total 74% of the X-chromosome, as well as for 8 deletions and point mutations derived in saturation mutagenesis screens of the fourth chromosome (Hochman 1976). With the exception of defects in head morphology and defects in cuticle differentiation, none of the hemizygous deletions showed phenotypes other than those predicted by point mutations known to lie in those regions. No deletion caused new or unknown alterations in gastrulation, segmentation or cuticle pattern.These results suggest that the number of genes required zygotically for normal embryonic patterning is small and that most, if not all such loci, are represented by point mutations in our collection.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848158
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  • 12
    Electronic Resource
    Electronic Resource
    The role of the peripodial membrane of leg and wing imaginal discs ofDrosophila melanogaster during evagination and differentiation in vitro (1984)
    Springer
    Development genes and evolution 193 (1984), S. 180-186 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Imaginal disc ; Morphogenesis ; Tissue culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The thin region of the peripodial membrane is confined to the area overlying the distal anlagen in thoracic discs. During the early stages of evagination the peripodial membrane is greatly stretched, but does not rupture. The appendage then evaginates through the stalk, probably by means of a contraction of the peripodial membrane. The cells of the peripodial membrane of leg and wing discs persist and differentiate sheets of trichomes characteristic of the ventral and lateral thorax. This is discussed in relation to imaginal disc fate maps.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848893
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  • 13
    Electronic Resource
    Electronic Resource
    TheUbx syndrome ofDrosophila: the prothoracic transformation (ppx) is independent ofbx, bxd andpbx (1984)
    Springer
    Development genes and evolution 193 (1984), S. 263-265 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Biothorax complex ; Prothoracic transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary If, early in development, theUbx + gene is removed by mitotic recombination from cells of the meso-and metathoracic leg primordia, theseUbx − cells develop as in the posterior prothoracic leg. We show that this transformation, termedpostprothorax, is a discrete genetic function that is independent of other homeotic transformations such asbx, pbx orbxd, which also result from the inactivation of theUbx gene.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01260349
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  • 14
    Electronic Resource
    Electronic Resource
    Mutations affecting the pattern of the larval cuticle inDrosophila melanogaster (1984)
    Springer
    Development genes and evolution 193 (1984), S. 283-295 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Larval cuticle ; Pattern formation ; Embryonic lethal mutations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The present report describes the recovery and genetic characterization of mutant alleles at zygotic loci on the third chromosome ofDrosophila melanogaster which alter the morphology of the larval cuticle. We derived 12600 single lines from ethyl methane sulfonate (EMS)-treatedst e orrucuca chromosomes and assayed them for embryonic lethal mutations by estimating hatch rates of egg collections. About 7100 of these lines yielded at least a quarter of unhatched eggs and were then scored for embryonic phenotypes. Through microscopic examination of unhatched eggs 1772 lines corresponding to 24% of all lethal hits were classified as embryonic lethal. In 198 lines (2.7% of all lethal hits), mutant embryos showed distinct abnormalities of the larval cuticle. These embryonic visible mutants define 45 loci by complementation analysis. For 32 loci, more than one mutant allele was recovered, with an average of 5.8 alleles per locus. Complementation of all other mutants was shown by 13 mutants. The genes were localized on the genetic map by recombination analysis, as well as cytologically by complementation analysis with deficiencies. They appear to be randomly distributed along the chromosome. Allele frequencies and comparisons with deficiency phenotypes indicate that the 45 loci represent most, if not all, zygotic loci on the third chromosome, where lack of function recognizably affects the morphology of the larval cuticle.
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    URL: http://dx.doi.org/10.1007/BF00848157
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  • 15
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    Early neurogenesis in wild-typeDrosophila melanogaster (1984)
    Springer
    Development genes and evolution 193 (1984), S. 308-325 
    Details
    ISSN: 1432-041X
    Keywords: Neurogenesis ; Pattern of neuroblasts ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary This paper deals with morphological aspects of early neurogenesis inDrosophila, in particular with the segregation of neuroblasts from the neurogenic region of the ectoderm and the pattern formed by those wells within both the germ band and the procephalic lobe. The neurogenic ectoderm was found to contain neural precursors intermingled with epidermal precursors, extending from the midline up to the primordia of the tracheal tree along the germ band and laterodorsally in the procephalic lobe. Germ band neuroblasts segregate from the neurogenic ectoderm during a period of several hours according to characteristic spatial and temporal patterns. During the first half of the segregation process the pattern of germ band neuroblasts was found to be the same in different animals in both spatial arrangement and number of cells; this permitted the identification of individual neuroblasts from different embryos. Later in development several difficulties were encountered which precluded an exact description of the neuroblast pattern. The constitution of the neurogenic region is discussed in relation to the phenotype of mutants affecting neurogenesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848159
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  • 16
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    The spatial arrangement of germ line cells in ovarian follicles of the mutantdicephalic inDrosophila melanogaster (1984)
    Springer
    Development genes and evolution 193 (1984), S. 388-393 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Oogenesis ; Ring canals ; Oocyte determination ; Polarity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The pattern of intercellular connections between germ line cells has been studied in follicles of the mutantdicephalic (dic), which possess nurse cell clusters at both poles. Staining of follicles with a fluorescent rhodamine conjugate of phalloidin reveals ring canals and cell membranes and thus allows us to reconstruct the spatial organization of the follicle. Each germ line cell can be identified by the pattern of cell-cell connections which reflect the mitotic history of individual cells in the 16-cell cluster. The results indicate that in both wild-type anddicephalic cystocyte clusters one of the two cells with four ring canals normally becomes the pro-oocyte. However, in some follicles (dicephalic and wild-type) oocytes were found with fewer or more than four ring canals. Indic follicles, one or several nurse cells may become disconnected from the other cells during oocyte growth at stage 9–10. Such disconnected cells cannot later on empty their cytoplasm into the oocyte. This, in turn, might be of consequence for the determination of axial polarity of the embryo.
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    URL: http://dx.doi.org/10.1007/BF00848229
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  • 17
    Electronic Resource
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    Cell interactions during the fusionin vitro ofDrosophila eye-antennal imaginal discs (1984)
    Springer
    Development genes and evolution 193 (1984), S. 406-413 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Imaginal disc ; Morphogenesis ; Tissue culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The fusion of the eye-antennal discs during culturein vitro has been investigated, and the complex morphogenetic movements which occur during the formation of the head capsule of the insect are described. The initial contact between the eye anlagen is by means of cell processes spanning the gap between the two discs. Subsequently the two epithelia become firmly apposed, and then the integrity of the epithelium in the region of fusion breaks down, cells appearing to move to new positions in order to form an epithelium which unites the two discs. The epithelium eventually secretes a pattern of cuticular structures which is continuous between the derivatives of the two discs. Bristles on either side of the line of fusion are perfectly aligned, and structures such as the median ocellus, which are formed jointly by the cells of the two discs, differentiate normally. This is also found when left and right eye-antennal discs of different genotypes are placed side-by-side, indicating that processes of pattern regulation can occur in culture.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848232
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  • 18
    Electronic Resource
    Electronic Resource
    Ethanol preference in rats with a prior history of acetaldehyde self-administration (1984)
    Springer
    Cellular and molecular life sciences 40 (1984), S. 1008-1010 
    Details
    ISSN: 1420-9071
    Keywords: Rat ; ethanol preference ; acetaldehyde self-administration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Peripherally self-injected acetaldehyde in interaction with environmental and nutritional variables significantly enhances alcohol drinking in rats and suggests an involvement of acetaldehyde in voluntary alcohol intake.
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    URL: http://dx.doi.org/10.1007/BF01946483
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  • 19
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    Selective inhibition of transition from sexual agglutination to zygote formation by ethyl N-phenylcarbamate in Saccharomyces cerevisiae (1984)
    Springer
    Archives of microbiology 137 (1984), S. 188-193 
    Details
    ISSN: 1432-072X
    Keywords: Agglutination substance ; α Pheromone ; Cell cycle ; Ethyl N-phenylcarbamate ; Mating reaction ; Microtubules ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Effects of ethyl N-phenylcarbamate (EPC) on the mating reaction of Saccharomyces cerevisiae were studied, with special attention on the effect on the α pheromone action. EPC inhibited zygote formation at a concentration which promoted induction of sexual agglutinability. EPC enhanced agglutinability induction by α pheromone, but inhibited α-pheromone-induced formation of large pearshaped cells in a mating type. The enhancement of agglutinability induction was accompanied with increased production of a agglutination substance and inhibition of α pheromone inactivation. EPC arrested the cell cycle of a cells probably in the step controlled by CDC19, CDC35, cAMP etc., just before the step controlled by CDC28, α pheromone etc.
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    URL: http://dx.doi.org/10.1007/BF00414541
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  • 20
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    Site of action of the natural algicide, cyanobacterin, in the blue-green alga, Synechococcus sp. (1984)
    Springer
    Archives of microbiology 138 (1984), S. 273-277 
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    ISSN: 1432-072X
    Keywords: Cyanobacteria ; Secondary metabolite ; Allelopathy ; Photosynthesis ; Electron transport ; Thylakoids ; Herbicides ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Cyanobacterin is a secondary metabolite produced by the cyanobacterium, Scytonema hofmanni. Highly purified cyanobacterin was found to inhibit the growth of many cyanobacteria at a minimum effective dose of 2 μg/ml (4.6 μM). The antibiotic had no effect on eubacteria including the photosynthetic Rhodospirillum rubrum. The site of action of cyanobacterin was further investigated in the unicellular cyanobacterium, Synechococcus sp. Electron micrographs of antibiotic-treated Synechococcus cells indicated that cyanobacterin affects thylakoid membrane structure. The antibiotic also inhibited light-dependent oxygen evolution in Synechococcus cells and in spheroplasts. These data support our conclusion that cyanobacterin specifically inhibits photosynthetic electron transport. This activity is similar to herbicides such as 3-(3,4-dichlorophenyl)-1,1-dimethyl urea (DCMU). The anhydro analog of cyanobacterin had no biological activity.
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    Structural analysis of EcoRI-DNA complexes as revealed by electron microscopy (1984)
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    Archives of microbiology 140 (1984), S. 265-270 
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    ISSN: 1432-072X
    Keywords: EcoRI ; EcoRI-DNA complexes ; EcoRI* activity ; Recognition sites ; Frequency of binding ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Electron microscopy of negatively stained isolated restriction enzyme EcoRI revealed particle projections with triangular or square outlines, indicating that the enzyme, in its tetrameric state, is tetrahedron-like. The two dimers making up the tetramer appear to be arranged in two planes orthogonal to each other. Complexes formed by EcoRI with the plasmids pBR322 or pGW10 were investigated by electron microscopic spreading techniques. In the presence of Mg2+, EcoRI was bound to the DNA molecules to form pearl necklace-like aggregates. The number of bound EcoRI particles was much higher as the sum of EcoRI-and 5′..AATT..3′ sites (with exceptions, the 5′..AATT..3′ sites may function as one type of EcoRI* sites) along the DNAs, indicating unspecific binding. In the absence of Mg2+, EcoRI was bound to the DNA only at the recognition site for EcoRI and the sites where the tetranucleotide sequence 5′..AATT..3′ was present. A direct correlation of the local concentrations of the bases A and T within the flanking sequences of the binding sites with the frequency of EcoRI to the DNA was observed. Dimers and tetramers of the enzyme was found to bind to the DNA. Tetramers occasionally exhibited two binding sites for DNA as indicated by the observation of DNA loops originating at the sites of bound tetrameric EcoRI particles.
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    Variation in the biochemical properties of the Drosophila alcohol dehydrogenase allozymes (1984)
    Springer
    Biochemical genetics 22 (1984), S. 153-168 
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    ISSN: 1573-4927
    Keywords: alcohol dehydrogenase ; Drosophila ; activity ratio ; specific activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Thirteen Drosophila Adh variants have been characterized with respect to gene expression, substrate preference, thermostability, and specific activity. The results suggest that the variants may be grouped into two biochemical classes, typified by the properties of the two most common enzyme forms, ADH-F and ADH-S. Membership of these classes cannot be predicted from electrophoretic mobility, nor is any simple classification possible with regard to the characteristics of level of gene expression (in terms of ADH activity or ADH protein) or thermostability of the gene product.
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    Acetaldehyde utilization and toxicity in Drosophila adults lacking alcohol dehydrogenase or aldehyde oxidase (1984)
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    Biochemical genetics 22 (1984), S. 1015-1029 
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    ISSN: 1573-4927
    Keywords: acetaldehyde ; alcohol dehydrogenase ; aldehyde oxidase ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Metabolic utilization and toxicity of acetaldehyde were studied in flies lacking alcohol dehydrogenase (ADH), aldehyde oxidase (AO), or both functions. Prior to the experiments, mutant alleles Adh n4 and mal were transferred to the same genetic background by 10 successive backcrosses. By comparison with wild-type flies, various deleterious, pleiotropic effects could be attributed to the mal allele but not to Adh n4 . Of the four genotypes studied (mal, Adh n4 , mal Adh n4 , and wild), all were able to use acetaldehyde as a resource in a similar way. In spite of its high toxicity, acetaldehyde appeared a better resource than ethanol. Flies treated with intermediate acetaldehyde concentrations (around 0.5%) exhibited a very high interindividual heterogeneity which could reflect a physiological adaptation occurring as a consequence of the aldehyde treatment. Toxicity tests showed that ADH-negative flies were more sensitive to acetaldehyde than wild type, but this is most likely explained by the transformation of the aldehyde into alcohol. Our results show that the aldehyde metabolizing enzyme (AME) system in Drosophila is neither ADH nor AO. The existence of an aldehyde dehydrogenase is plausible.
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    Correlated response to phototactic selection (1984)
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    Behavior genetics 14 (1984), S. 279-293 
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    ISSN: 1573-3297
    Keywords: phototaxis ; Drosophila ; correlated response ; selection ; sepia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract Artificial selection for positive and negative phototaxis was conducted in populations ofDrosophila melanogaster that were polymorphic at thesepia locus. Photoselection response was accompanied by a correlated response in the frequency of thesepia allele. Changes insepia frequency were shown to be significantly different from those predicted by several neutral models. Implications of this correlated response are briefly discussed in terms of the neurogenetic basis of phototaxis.
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    A note on barometric pressure and behavior inDrosophila pseudoobscura (1984)
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    Behavior genetics 14 (1984), S. 315-317 
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    ISSN: 1573-3297
    Keywords: Drosophila ; mating and barometric pressure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract During a study ofDrosophila mating behavior we observed unexpected changes in performance under ostensibly identical experimental conditions. We related the behavior during the 17 days of the experiment to changes in ambient humidity and barometric pressure. Humidity had no significant effect, but reduced barometric pressure was found to be associated with reduced mating activity (R 2=0.29,P〈0.025), accounting for close to 30% of the variation in total number of matings.
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    Genetic elements of courtship inDrosophila: Mosaics and learning mutants (1984)
    Springer
    Behavior genetics 14 (1984), S. 383-410 
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    ISSN: 1573-3297
    Keywords: Drosophila ; courtship ; learning ; circadian
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
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    URL: http://dx.doi.org/10.1007/BF01065442
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    Genetic analysis of sex appeal inDrosophila (1984)
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    Behavior genetics 14 (1984), S. 411-440 
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    ISSN: 1573-3297
    Keywords: Drosophila ; courtship ; pheromones
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
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    Drosophila Learning: Behavior and biochemistry (1984)
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    Behavior genetics 14 (1984), S. 527-557 
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    ISSN: 1573-3297
    Keywords: Drosophila ; learning ; classical conditioning mutants ; cAMP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
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    URL: http://dx.doi.org/10.1007/BF01065446
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    A few chemical words exchanged byDrosophila during courtship and mating (1984)
    Springer
    Behavior genetics 14 (1984), S. 441-478 
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    ISSN: 1573-3297
    Keywords: Drosophila ; courtship ; pheromones
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Summary Experimental evidence and speculation relative to chemical messages exchanged byDrosophila during courtship and mating are reviewed. Only the speciesD. melanogaster andD. simulans are considered in detail. Emphasis is put on female aphrodisiacs, as they clearly participate in sex and species recognition. All the aphrodisiac molecules described are unsaturated long-chain hydrocarbons, and position 7 for a double bond seems important in both species. InD. melanogaster, only females are able to make 7,11-dienes, compounds which stimulate males of this species to court. InD. simulans, 7-tricosene plays a similar role but is produced by both sexes as well as maleD. melanogaster. In both species, polymorphism is shown for these molecules. Their biosynthesis is also considered and both preliminary biochemical and genetic data are introduced. Male-specific compounds which regulate male and female behaviors are also reviewed. For example,cis-vaccenyl acetate inhibits male courtship; one or two peptides control the female's receptivity and egg laying. Such compounds are transferred from males to females together with sperm.
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    A reexamination of the negative assortative mating phenomenon and its underlying mechanism inDrosophila melanogaster (1984)
    Springer
    Behavior genetics 14 (1984), S. 45-61 
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    ISSN: 1573-3297
    Keywords: assortative mating ; polymorphism ; partner selection ; pheromone ; behavior ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract Averhoff and Richardson [(1974)Behav. Genet. 4:207–225] reported a trend toward negative assortative mating inDrosophila melanogaster during the course of inbreeding. These authors proposed that the underlying mechanism was based on pheromone polymorphism and male selection. Mass mating experiments were carried out to verify their hypothesis, detailed behavior observations were made to identify the underlying mechanism, and sex pheromone composition and variation were examined by using gas chromatography-mass spectrometry analysis. The results showed that negative assortative mating is not a general phenomenon. Although male pheromones are probably polymorphic, female pheromones are not. We found no evidence for male selection as predicted by Averhoff and Richardson. It is argued that the most parsimonious mechanism underlying negative assortative mating is similar to one proposed by Bryant [(1979)Behav. Genet. 9:249–256], which was based on interstrain differences in female reluctancy and male vigor.
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    The analysis of mating behavior data (1984)
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    Behavior genetics 14 (1984), S. 153-156 
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    ISSN: 1573-3297
    Keywords: mating behavior ; statistical analysis ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract Quite different sets of data are shown to generate identical output ratios so that analyses of mating behavior data based on the use of input and output ratios may obscure significant aspects of the mating behavior.
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    Learning in three species of diptera: The blow flyPhormia regina, the fruit flyDrosophila melanogaster, and the house flyMusca domestica (1984)
    Springer
    Behavior genetics 14 (1984), S. 479-526 
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    ISSN: 1573-3297
    Keywords: Drosophila ; learning ; conditioning
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
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    Lectin-binding properties of the Merkel cell and other root sheath cells in perinatal rat vibrissae (1984)
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    Cell & tissue research 236 (1984), S. 373-381 
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    ISSN: 1432-0878
    Keywords: Merkel cell surface ; Quinacrine fluorescence ; Lectins ; Vibrissae ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Surface carbohydrates on the Merkel cell of the outer root sheath (ORS) were investigated in 1to 4-day-old rat vibrissae by use of rhodamine isothiocyanate (RITC)-conjugated lectins. The red fluorescence of RITC provided a convenient assay for lectin binding to the Merkel cell, which is itself identified by its green fluorescence following selective uptake of the dye quinacrine. In monolayers or suspensions of freshly dissociated ORS cells, the Merkel cell showed high affinity for the α-fucose-specific lectin, Ulex europeus agglutinin I (UEA-I), thus revealing a novel feature for a basally located cell. Other high-affinity lectins included concanavalin A (Con A), wheat germ agglutinin (WGA), soybean agglutinin (SBA), and Ricinus communis agglutinin I (RCA-I). In contrast, Dolichos biflorus (DBA), Bandeiraea simplicifolia I and II (BS-I and BS-II), and peanut agglutinin (PNA) virtually excluded the Merkel cell, though PNA-binding sites were unmasked after neuraminidase treatment. Other dispersed ORS cells had varying lectin affinities, and generally binding was inhibited by a competing haptenic sugar. The pattern of lectin binding seen in cryostat and paraffin sections of the vibrissa suggested that the Merkel cells share surface properties with their neighboring basal and/or spinous cells; however, unshared properties are likely to exist since ingrowing mechanosensory nerves recognize the Merkel cells, and not other epidermal cells, as their targets.
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    Arachnoid mater of the bullfrog, Rana catesbeiana (1984)
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    Cell & tissue research 236 (1984), S. 693-697 
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    ISSN: 1432-0878
    Keywords: Intermediate filaments ; Microtubules ; Caveolae ; Bullfrog ; Arachnoid mater ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the bullfrog, the meninges surrounding the central nervous system include an arachnoid mater that contains layers of cells with abundant intermediate filaments (IFs) having unique organizational characteristics. This membrane contains an inner lamina of cells that resemble fibroblasts and an outer lamina of flattened cells that are almost filled with IFs. The IFs of the outer arachnoid are arranged in compact, arching bundles that lie parallel to the outer surface of the central nervous system. Thus, sections cut tangentially to the membrane reveal bending of filament bundles, whereas transverse sections do not. In some cells bordering the subdural space, bundles of filaments are organized into highly-ordered spiral arrays. Attachments to the numerous desmosomes and, apparently, to the nuclear envelope suggest anchoring of cytoplasmic structures by the IF system. Microtubules occur primarily near the plasma membrane and the nucleus. Numerous caveolae also are associated with the plasma membrane. The unusual abundance, organization, and cytoplasmic relations of IFs in the bullfrog arachnoid suggest that this membrane may serve as an important model for study of fundamental cytoskeletal relations and function.
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    Administration of caerulein to rats promotes antral epithelial cell renewal (1984)
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    Cell & tissue research 236 (1984), S. 711-715 
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    ISSN: 1432-0878
    Keywords: Gastric antral mucosa ; Caerulein ; Gastrointestinal hormones ; Cholecystokinin ; Trophic effect ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The growth-promoting effect of caerulein on antral gastric mucosa was explored using Wistar rats. Implanted osmotic minipumps were used to administer submaximal doses of either caerulein or saline to normal rats for up to 4 days. In one group, reflux of bile and pancreatic juice into the stomach was avoided by previous surgical diversion of the distal common bile duct to the jejunum. DNA synthetic and mitotic activity in the antrum epithelium were estimated by 3H-thymidine pulse labelling and autoradiography during the administration of the peptide. The rate of cell migration was determined in animals killed 1, 2 and 3 days after the 3H-thymidine pulse. Administration of caerulein to normal rats provoked significant increases in both labelling and mitotic indices, and a significant acceleration of the upward cell migration in the glandular tubes. In the animals with distal diversion of bile and pancreatic secretions both labelling and mitotic indices were also increased over control values under the effect of the peptide. These data indicate that administration of caerulein stimulates cell proliferation in the antral gastric mucosa. This effect cannot be explained through increased reflux of pancreaticobiliary secretions in the stomach.
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    Morphometric studies on lipid inclusions in Sertoli cells during the spermatogenic cycle in the rat (1984)
    Springer
    Cell & tissue research 236 (1984), S. 699-709 
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    ISSN: 1432-0878
    Keywords: Testis ; Spermatogenic cycle ; Sertoli cell ; Lipid ; Morphometry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The volume and surface area of lipid inclusions often present in the cytoplasm of rat Sertoli cells was measured directly from semi-thin sections of perfusion-fixed testicular tissues using an image analyser linked to a light microscope. Sertoli cell nuclei were used as a reference for comparing any variations in the measured parameters of lipid inclusions during the rat spermatogenic cycle. Volume density of Sertoli cell lipid inclusions was assessed by morphometric analysis of Sertoli cells photographically reconstructed from electron micrographs. Maximum lipid content in Sertoli cells occurred during stages IX–XIV of the spermatogenic cycle, then declined at stages I–III and remained low from stages IV–VIII. The persistence and increase in number of many large Sertoli cell lipid inclusions beyond the stage where spermatid residual bodies are phagocytosed within the Sertoli cells (stage IX) suggests that the synthesis and lipolysis of Sertoli cell lipid inclusions represents an intrinsic functional cycle of the Sertoli cells. Stage-dependent variations in the lipid content of rat Sertoli cells offers morphological evidence that the metabolic duties of the Sertoli cells are synchronised with the spermatogenic cycle to provide local coordination of the proliferation and maturation of the germ cells.
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    The ovarian follicle as a model for the cell-mediated control of tissue growth (1984)
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    Cell & tissue research 236 (1984), S. 717-724 
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    ISSN: 1432-0878
    Keywords: Ovary ; Ovarian follicle ; Atresia ; Immunoregulation ; Immune tolerance ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Thy-1+ cells, producing Thy-1+ material, have been demonstrated by the indirect immunoperoxidase technique in the theca of growing ovarian follicles of the rat. OX-2 antigen, known as the minor glycoprotein of rat thymocytes, was detected in granulosa cells of non-growing follicles. Ia+ cells of dendritic type and/or activated macrophages were identified in the granulosa of advanced degenerating follicles, and remnants of the zona pellucida exhibited immunoglobulins. In some ovaries immunoglobulins were also bound to the zona pellucida of oocytes of early degenerating antral follicles. Medium-sized antral follicles with degenerating granulosa were occasionally invaded by cells carrying antigens of cytotoxic T lymphocytes or other T lymphocyte subsets, while degenerating large antral follicles were sometimes invaded by cells exhibiting antigen of cells with natural killer function (but not antigens of T lymphocytes). Granulosa cells of some degenerating antral follicles exhibited class-I antigens derived from the major histocompatibility complex. We suggest that cell-mediated control mechanisms of antigen expression and metabolism of tissue cells during their differentiation and degeneration should be considered in addition to the well-documented hormonal dependence of some tissues.
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    Ultrastructural changes in the spermatogonia and spermatocytes of Poecilia reticulata during spermatogenesis (1984)
    Springer
    Cell & tissue research 237 (1984), S. 219-226 
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    ISSN: 1432-0878
    Keywords: Spermatogonia ; Spermatocytes ; Carbohydrates ; Guppy ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The structure of guppy (Poecilia reticulata) spermatogonia and spermatocytes has been studied using electron microscopy. The spermatogonia, situated at the apex of the seminiferous tubule, are almost all surrounded by a network of Sertoli cells; they have very diffuse chromatin and one or two large nucleoli. The cytoplasm contains relatively few organelles, although annulate lamellae are found. The mitochondria have few cristae and are concentrated at one pole of the cell; they are sometimes found with intermitochondrial cement. These spermatogonia are separated from each other, having no intercellular bridges or inclusion in Sertoli cells, and are relatively undifferentiated; they correspond to stem cells. The spermatogonia beneath the apex are organized into cysts. First-generation spermatogonia are more dense and heterogeneous, their nuclei becoming smaller and their chromatin becoming denser during successive generations. In spermatocytes, the synaptinemal complex exists as a modified form until metaphase. The concentration of organelles in the cytoplasm increases and the organelles become more diversified as spermatogenesis progresses. Many cytoplasmic bridges are observed (several per cell), indicating that the cells remain in contact after several divisions. These changes in germ cell structure have been related to some of the characteristic features of spermatogenesis in guppy, e.g. the large number of spermatogonial generations and the complexity of spermiogenesis.
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    Glial cells in the pineal gland of mice and rats (1984)
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    Cell & tissue research 237 (1984), S. 245-252 
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    ISSN: 1432-0878
    Keywords: Pineal organ ; Interstitial cells ; Astrocytes ; Immunocytochemistry ; Rat ; Mouse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Antigenic markers characteristic of astrocytes and their differentiative states (i.e., glial fibrillary acidic protein (GFAP), vimentin, and M1 and C1 antigens) were investigated in the pineal gland of mouse and rat using double immunolabeling techniques. In both species the socalled interstitial cells as characterized by TEM were shown to be astrocytes, since they expressed vimentin, but neither fibronectin (a marker for fibroblasts and endothelial cells) nor the neuron-specific L1 antigen or tetanus toxin receptors. Subpopulations of vimentin-positive pineal astrocytes were also GFAP- and C1- antigen-positive. M1- antigenpositive cells were not detected. It is concluded that a considerable proportion of interstitial cells in the pineal gland of rat and mouse are immature astrocytes which, in contrast to other parts of the central nervous system, persist into adulthood.
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    Evidence for a role of the cytoskeleton in the in vitro folliculogenesis of the thyroid gland of the fetal rat (1984)
    Springer
    Cell & tissue research 237 (1984), S. 499-508 
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    ISSN: 1432-0878
    Keywords: Thyroid gland, fetal ; Cytoskeleton ; Cytocha lasin B ; Vinblastine ; Colchicine ; Follicular development (thyroid) ; Tissue culture ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Thyrotropic hormone (TSH) or cAMP accelerate the formation of follicular cavities in the explanted thyroid gland of the 15-day-old rat fetus. Cytochalasin B or vinblastine and nocodazole or colchicine, which disorganize microfilamental and microtubular structures respectively, inhibit or completely block in vitro-induced folliculogenesis. Exposure of the thyroid tissue to lumicolchicine, a structural isomer of colchicine deprived of antimicrotubular activity, does not inhibit the activation of folliculogenesis induced by TSH. These results are strong evidence for the supposition that microfilaments and microtubules are involved in the TSH-stimulated mechanisms resulting in thyroid folliculogenesis. Folliculogenesis requires the integrity of both microfilaments and microtubules.
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    Marginal plates in hepatic peroxisomes of Ichthyophis glutinosus (Amphibia: Gymnophiona) (1984)
    Springer
    Cell & tissue research 238 (1984), S. 413-416 
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    ISSN: 1432-0878
    Keywords: Peroxisomes ; DAB-cytochemistry ; Electron microscopy ; Liver, amphibian ; Gymnophiona ; Ichthyophis glutinosus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of hepatic peroxisomes was investigated in Ichthyophis glutinosus (Amphibia: Gymnophiona), employing perfusion fixation and the diaminobenzidine (DAB) technique for the visualization of catalase. The majority of peroxisomes is circular or rod-shaped, although elongated particles occasionally occur. They contain a finely granular matrix, lightly stained after the DAB procedure. Their mean diameter is approximately 0.25 μm. Serial sections reveal that the circular and rod-shaped peroxisomal profiles are cross and oblique sections of highly tortuous, tubular organelles exceeding 2 μm in length. In addition to tubular profiles, elongated, rectangular particles, as well as straight dumbbell-shaped organelles with distinct marginal plates are observed. They range from 900 to 1650 nm in length (mean = 1200 nm). In the flattened, thin central portion of the dumbbell-shaped particle, the peroxisomal membranes form a cisterna enclosing one or two uniformly thick marginal plates, which display a definite substructure with a periodicity of 10 nm. These findings indicate that peroxisomes in the liver of Ichthyophis exhibit a complex organization. It is suggested that the organelles undergo a specific differentiation process, morphologically characterized by the formation of enlarged segments of unusual shape.
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    Immunohistochemical study on the development of CRF-containing neurons in the hypothalamus of the rat (1984)
    Springer
    Cell & tissue research 238 (1984), S. 539-544 
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    ISSN: 1432-0878
    Keywords: CRF-neurons ; Hypothalamus ; Development, ontogenetic ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Appearance of immunoreactive corticotropin-releasing factor (CRF)-containing neurons was studied in developing hypothalamus of the rat by use of antisera against rat- and ovine CRF. These neurons were first recognized in the lateral and paraventricular nuclei on days 15.5 and 16.5 of gestation, respectively, when antiserum against rat CRF was employed. Antiserum against ovine CRF revealed the cells two days later exclusively in the latter nucleus. In both nuclei, the neurons increased in number with development. The neurons in the paraventricular nucleus appeared to project their immunoreactive processes to the median eminence via the periventricular and lateral pathways. In the median eminence, the immunoreaction with antiserum to rat CRF was first recognized in its anterior portion in the form of dots on day 16.5 of gestation but as beaded fibers in the external layer on day 17.5; these structures increased in amount with development in rostro-caudal direction. Although antiserum to ovine CRF was less potent in immunostainability than antiserum to rat CRF, it also revealed the beaded fibers in the median eminence on day 17.5 of gestation. Since evidence is available that the paraventricular nucleus is involved in corticotropin release, it is concluded that, in rats, the hypothalamic regulatory mechanism controlling the release of corticotropin initially appears on days 16.5–17.5 of gestation.
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    Studies on the morphology of the isolated perfused rabbit ovary (1984)
    Springer
    Cell & tissue research 235 (1984), S. 59-63 
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    ISSN: 1432-0878
    Keywords: Ovulation (rabbit) ; Graafian follicle ; Perfusion ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Isolated ovaries from untreated, sexually mature rabbits were introduced into an in vitro perfusion system and perfused with a chemically defined medium containing albumin. The ovaries were perfused for up to 15 h (mean 11.5 h) and then processed for morphological investigation. Both at the light- and electron-microscopical levels, most of the ovaries exhibited a normal structure comparable with ovaries in situ. In two cases, however, marked accumulations of bacteria were found, although not inside the follicles. Since ovulation in the rabbit normally occurs between 9.5–13 h after mating or human chorionic gonadotrophin treatment, this model seems adequate for studies of ovulation in vitro. It is, however, important to study the ovaries microscopically after the perfusion to detect artifacts, e.g., bacterial infection, that may have influence on the process of ovulation.
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    Regions of putative acetylcholine receptors at synaptic contacts between neurons maintained in culture and subsequently fixed in solutions containing tannic acid (1984)
    Springer
    Cell & tissue research 235 (1984), S. 85-89 
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    ISSN: 1432-0878
    Keywords: Tannic acid ; Acetylcholine receptors ; Tissue culture ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Spinal cord neurons from 9-day chick embryos were maintained in culture for up to 35 days and then fixed in 4% cacodylate-buffered glutaraldehyde containing 2% tannic acid. After about 15 days in culture a small percentage of the synaptic specializations present were characterized by striking electron-dense striations averaging 15 nm in width, oriented perpendicular to the postsynaptic membrane. These structures increased in frequency with time in culture (to a maximum of about 10% of all synapses in the oldest cultures); they were asymmetrical, protruding approximately 8 nm into the synaptic cleft, and more deeply (approximately 15–18 nm), into the postsynaptic cytoplasm. On the basis of earlier work by Sealock (1980) they are interpreted as concentrations of acetylcholine receptors. Similar membrane differentiations were also seen associated with active-zone areas of a few presynaptic membranes, and the possibility that these represent presynaptic acetylcholine receptors is discussed. Additional observations reported are (1) the presence of striations resembling those seen at the postsynaptic membrane in the membranes of some postsynaptic vesicles, and (2) filamentous links between the striations and cytoskeletal elements of the postsynaptic cell.
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    URL: http://dx.doi.org/10.1007/BF00213727
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    Immunocytochemical demonstration of caldesmon (a calmodulin-binding, F-actin-interacting protein) in smooth muscle fibers and absorptive epithelial cells in the small intestine of the rat (1984)
    Springer
    Cell & tissue research 235 (1984), S. 207-209 
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    ISSN: 1432-0878
    Keywords: Caldesmon ; Actin ; Immunocytochemistry ; Small intestine ; Smooth muscle ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distribution of caldesmon (a calmodulin-binding, F-actin-interacting protein) (Sobue et al. 1982) and of actin was studied in the rat's small intestine by means of light-microscopic immunocytochemistry. Positive immunostaining for caldesmon was seen in smooth muscle cells of the intestinal wall, and of blood vessels, and in the apical portion of the absorptive epithelial cells. The immunoreactivity in goblet cells was difficult to recognize. The positive reaction to immunostaining for actin showed almost the same pattern as that for caldesmon. These results suggest that this calmodulin-binding protein may play an important role in the control of actin-myosin interaction in smooth muscle cells and in non-muscle cells.
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    URL: http://dx.doi.org/10.1007/BF00213742
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    Internalization of ferritin-concanavalin A by the lactating mammary cell in vivo (1984)
    Springer
    Cell & tissue research 235 (1984), S. 433-438 
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    ISSN: 1432-0878
    Keywords: Mammary gland ; Ferritin-concanavalin A ; Concanavalin A ; Endocytosis ; Membrane reuse ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ferritin-concanavalin A (Fer-Con A) was used to label the apical plasma membrane of the lactating cell to determine whether membrane internalization takes place. Rat glands were infused in vivo via the teat with 0.2 mg of Fer-Con A in 0.2 ml tris buffer (pH 7.0) containing 0.1% trypan blue, the latter acting as a marker of the infusate. Tissues were obtained from separate animals 5, 10 and 60 min postinfusion. Fer-Con A was seen in alveolar lumina bound to the outer surfaces of apical plasma membrane, microvilli and milk fat globules. It was observed within lactating cells on the inner membrane surfaces of endocytotic vesicles, Golgi cisternae, and secretory vesicles containing casein micelles, and in multivesicular bodies and lysosomes. Internalization of the ferritin-lectin conjugate into casein-containing secretory vesicles was detectable in the 5-min postinfusion tissue. Lysosomes were the only structures in control tissue that contained particles bearing some resemblance to Fer-Con A. The data provide evidence that apical plasma membrane is internalized and distributed to a number of intracellular compartments.
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    Suprachiasmatic nucleus: Numbers of synaptic appositions and various types of synapses (1984)
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    Cell & tissue research 235 (1984), S. 449-452 
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    ISSN: 1432-0878
    Keywords: Suprachiasmatic nucleus ; Morphometry ; Synapses ; Sexual dimorphism ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The suprachiasmatic nucleus (SCN) of male rats was estimated to contain 16×106 synaptic appositions (unilaterally) or 250×106 appositions in 1 mm3 tissue of the nucleus with an average of 1404 appositions per neuron. There are significantly fewer synaptic appositions in the suprachiasmatic nucleus of female rats (15×106 per SCN or 236×106 in 1 mm3 tissue of SCN with 1264 appositions per neuron on an average). Additionally, numbers of various types of synapses (axo-somatic, invaginated, dendrodendritic and optic) are estimated.
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    Regional effect of monosodium-L-glutamate on the superficial layers of superior colliculus in rat (1984)
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    Cell & tissue research 235 (1984), S. 453-457 
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    ISSN: 1432-0878
    Keywords: Monosodium-1-glutamate ; Neuropathology ; Rat ; Superior colliculus ; Toxicology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Systemic administration of monosodium-1-gluta-mate by single injections of 4 mg/g body weight in infant rats (2–10 days of age) results in acute swelling of cytoplasm and nuclear pyknosis of neurons in the stratum zonale and stratum griseum superficiale of the superior colliculus. Multiple daily doses of 4 mg/g body weight monosodium-1-glutamate result in an almost complete loss of neurons in these two superficial layers. The deeper layers appear not to be affected. No pathological effects were observed in the lateral geniculate body or pretectal complex. Light-and electron-microscopic studies reveal that the optic nerves are remarkably shrunken and many myelinated as well as unmyelinated axons are lost. Injection of 3Hproline into the vitreous body of one eye results in limited transport to the suprachiasmatic nucleus, lateral geniculate body and to lateral portions of the superior colliculus. The small percentage of intact axons in the optic nerve, as well as the limited proline transport from the eye, suggest that administration of monosodium-1-glutamate leaves intact some optic fibers, a portion of which belongs to the retinohypothalamic tract.
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    Fine structure of monoamine-containing basal cells in the taste buds on the barbels of three species of teleosts (1984)
    Springer
    Cell & tissue research 235 (1984), S. 479-484 
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    ISSN: 1432-0878
    Keywords: Monoamine-containing cells ; Taste bud ; Paracrine cells ; Mechanoreceptors ; Electron microscopy ; Teleosts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The taste buds on the barbels in three species of teleosts (Cyprinus carpio, Misgurnus anguillicaudatus, Parasilurus asotus) were studied by means of fluorescence and electron microscopy. Intensely yellow-fluorescent cells, which are disk-shaped and located exclusively in a basal position, are observed in the barbel-buds of all fishes examined. The basal cells contain a large number of small clear vesicles approximately 40–60 nm in diameter, which show a tendency to aggregate in the cytoplasm facing the junction of the nerve terminals; chemically transmitting synapses are seen in the latter region. It is suggested from the present observations that the basal cells in the barbel-bud may originate from Schwann cells and have a dual function both as mechanoreceptors and paracrine elements. Since the administration of 5,6-DHT results in an appearance of small dense vesicles among the small clear vesicles, the possibility exists that the basal cell may be capable of taking up monoamines and storing them in the small clear vesicles.
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    Electron-microscopic demonstration of the distribution of calcium deposits in the exocrine pancreas of the rat after application of carbachol, atropine, cholecystokinin, and procaine (1984)
    Springer
    Cell & tissue research 235 (1984), S. 683-690 
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    ISSN: 1432-0878
    Keywords: Exocrine pancreas ; Calcium pool ; Calcium release ; Electron microscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In an attempt to identify a cellular Ca2+-pool, from which calcium is released when secretagogues are applied, tissue fragments of the rat exocrine pancreas were incubated and fixed with glutaraldehyde in the presence of calcium. By means of this procedure electron-dense deposits were found on plasma membranes. X-ray microanalysis showed that these deposits contain calcium. Stimulation of tissue fragments with the use of the secretagogues carbachol or cholecystokinin reduced the number of deposits by about 80%. When the antagonist atropine was applied after carbachol stimulation, deposits reappeared on cell membranes, which then disappeared again after a second stimulation with cholecystokinin. In the presence of procaine, carbachol was inhibited and only slightly reduced the Ca2+-deposits on the plasma membranes. These results suggest that a calcium pool, from which calcium is released to induce enzyme secretion on stimulation, is located in the cell membrane
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    Intermediate filaments, microtubules and microfilaments in epidermis of sea urchin tube foot (1984)
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    Cell & tissue research 236 (1984), S. 27-33 
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    ISSN: 1432-0878
    Keywords: Intermediate filaments ; Microtubules ; Microfilaments ; Sea urchin ; Cytoskeleton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Tube foot epidermal cells of the sea urchin Strongylocentrotus purpuratus were examined by transmission electron microscopy and fluorescence microscopy to identify the chemical nature of prominent bundles of cytoplasmic filaments. Cross sections revealed filaments of roughly 7–8 nm in diameter closely packed into dense bundles. These bundles, in turn, were each surrounded by a loose sheath of microtubules. The filament size and negative reaction with the fluorescent F-actin binding drug NBD-phallacidin indicated that they were not actin. Indirect immunofluorescence microscopy of whole tissues and frozen sections revealed a strong reaction of the filaments with a monoclonal antibody prepared against porcine stomach desmin. In SDS-polyacrylamide gels of whole tube foot protein, a band of apparent molecular weight around 50 000 daltons reacted with the anti-desmin monoclonal antibody. The combined data provide evidence that the epidermal filament bundles are related to vertebrate intermediate filaments, but further biochemical studies will be necessary to assign them to a particular class of filament proteins.
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    Ontogenetic appearance of somatostatin-containing nerve terminals in the median eminence of rats (1984)
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    Cell & tissue research 236 (1984), S. 47-51 
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    ISSN: 1432-0878
    Keywords: Somatostatin ; Ontogenesis ; Electron-microscopic immunohistochemistry ; Median eminence ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The development of immunoreactive (ir) somatostatin-containing nerve terminals in the rat median eminence (ME) has been examined electron-microscopically. Nerve fibers containing ir particles scattered throughout the axoplasm are first seen in the external layer of the ME on day 18.5 of gestation, and, on day 21.5 appear to terminate on the basement membrane of the perivascular space of the portal vessels. After birth, the fiber terminals contain several membrane-limited granules, which are labeled with ir PAP particles. Ultrathin, Epon-embedded sections of ME, treated by the protein A gold-labeling method for somatostatin, demonstrate positively labeled granules in the nerve fibers in the postnatal ME, but in the prenatal tissue, no specific gold-labeling is found. These findings show that, in the external layer of the ME, somatostatin storing occurs in the granules in the axonal terminals after birth.
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    Morphological and morphometrical changes in chloride cells of the gills of Pimephales promelas after chronic exposure to acid water (1984)
    Springer
    Cell & tissue research 236 (1984), S. 121-128 
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    ISSN: 1432-0878
    Keywords: Chloride cells ; Acid stress ; Gill ; Electron microscopy ; Fathead minnow
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Fathead minnows, Pimephales promelas, were exposed for 129 days to Lake Superior water acidified with sulfuric acid by means of a flow-through toxicant injection system. The effects of chronic acid stress (pH 6.5, 6.0, 5.5, 5.0) on gill histology were examined. Most of the histological effects were seen at pH 5.5 and 5.0 and were confined primarily to changes in numbers, distribution, and morphology of chloride cells. At low pH levels there tend to be more chloride cells in the gill epithelium and an increased percentage of these cells in the secondary lamellae. In contrast to normal chloride cells, chloride cells from fish exposed to low pH frequently had apical pits while some had bulbous apical evaginations. The occurrence of structural changes in chloride cells during exposure to acid water suggests that chloride cells may be involved in acclimation to acid stress.
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    Morphometric evaluation of lipid droplet associations with secretory vesicles, mitochondria and other components in the lactating cell (1984)
    Springer
    Cell & tissue research 236 (1984), S. 471-475 
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    ISSN: 1432-0878
    Keywords: Lactating cell ; Lipid droplets ; Secretory vesicles ; Mitochondria ; Intracellular associations ; Electron microscopy ; Milk secretion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The size, cellular location, and identity of surface-associated components were determined for lipid droplets in lactating cells. Transmission electron-microscopic measurements were made involving 3801 droplets in approximately 211 cells from three rats and 1197 droplets in 66 cells from a mouse. For the purposes of droplet evaluation, cells were divided into seven locations ranging from basal to secreting positions. Droplets were also categorized with respect to contact with other droplets, basolateral plasma membrane, mitochondria, Golgi apparatus, secretory vesicles, and endoplasmic reticulum-cytoplasm (ERC). Data on droplet size showed that droplet growth occurs mainly in the secretory position, confirming previously published findings. Lipid droplets from mouse tissue, although somewhat smaller in size showed similar growth trends to those of the rat. Data on numbers of droplet contacts and percentages of droplet circumferences involved in associations with other cell components showed that the dominant interaction of lipid droplets was with the ERC. However, intimate association of droplets with mitochondria was noted in all cellular locations. In addition, nursed animals exhibited a greater proportion of droplet surface association with secretory vesicles and less in contact with mitochondria in comparison to those not nursed. The significance of these relationships to milk synthesis and secretion is discussed.
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    Identification of pericytes in the central nervous system by silver staining of the basal lamina (1984)
    Springer
    Cell & tissue research 236 (1984), S. 491-493 
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    ISSN: 1432-0878
    Keywords: Brain vessels ; Basal lamina ; Pericytes ; Endothelial cells ; Glial cells ; Argyrophilic staining ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Vibratome sections obtained from perfusion-fixed rat brains were stained by means of silver impregnation and physical development according to Gailyas (1970). Small pieces of the cerebral cortex were postfixed with buffered osmium tetroxide solution and processed for electron microscopy to examine the localization of the silver deposit at the cellular level. The cell surfaces of pericytes and smooth muscle cells were completely outlined by silver grains. Endothelial cells and perivascular astrocytes, however, showed an asymmetric distribution of the silver deposit, i.e., the deposit was restricted to the abluminal endothelial surface and to the astrocytic membrane adjacent to the vessel wall, respectively. The method allowed a clear-cut distinction between perikarya of endothelial cells and pericytes as well as glial cells in perivascular position, even at the light-microscopic level.
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    Electron-microscopic study of silver staining of nucleoli in growing oocytes of rat ovaries (1984)
    Springer
    Cell & tissue research 236 (1984), S. 249-255 
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    ISSN: 1432-0878
    Keywords: Oocyte ; Nucleolus ; Silver staining ; Electron microscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The nucleoli of dictyate-stage growing oocytes in rat ovaries were examined both with routine electron microscopy and electron microscopy after silver nitrate and ammoniacal silver nitrate (Ag-AS) staining. The nucleoli of the unilaminar follicular oocytes consist of twisted strands of dense fibrillar components, aggregates of granular components, and small fibrillar centers. After Ag-AS staining, silver grains are numerous on the dense fibrillar strands, fewer on the fibrillar centers, and very sporadic on the granular aggregates. The same stainability of three nucleolar components with the Ag-AS method was also confirmed in the nucleoli segregated by actinomycin D. During the transition of growing oocytes from bilaminar to plurilaminar follicle stage, the nucleolar dense fibrillar strands gradually conglomerate and are transformed into large and compact spherules. The stainability of dense fibrillar components with the Ag-AS method was lost along with this nucleolar transformation. These results may provide some new clues on the functional significance of AgAS-positive proteins in the nucleoli.
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    Independent development of presynaptic specializations in olfactory cortex of the fetal rat (1984)
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    Cell & tissue research 237 (1984), S. 103-109 
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    ISSN: 1432-0878
    Keywords: Synapses ; Synaptogenesis ; Development fetal ; Olfactory cortex ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Electron microscopy was used to study synaptogenesis in prepyriform cortex of fetal rat pups during early stages of synapse formation. Of special interest is the frequent occurrence of unapposed, developing synaptic specializations in axon and growth cone profiles. The location and morphology of the unapposed specializations suggests that thay are presynaptic in nature. These presumably immature presynaptic specializations are found in the lateral olfactory tract and subjacent cortex. Intermediate forms between uncontacted presynaptic specializations and definitive synapses suggest a synaptogenic sequence in which initial development of an immature presynaptic specialization begins without apposition of a postsynaptic element at that location. This implies that initiation of presynaptic development is not dependent upon postsynaptic contact and also raises the question of whether synaptic contacts could be established via presynaptic induction of postsynaptic formation.
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    Connexon rearrangement in cardiac gap junctions: Evidence for cytoskeletal control? (1984)
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    Cell & tissue research 237 (1984), S. 185-186 
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    ISSN: 1432-0878
    Keywords: Gap junction ; Cytoskeleton ; Heart ; Ultrarapid freezing ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Using ultrarapid-freezing techniques and freezefracture electron microscopy, we report here a close association between cardiac gap junctions and specialized membrane domains containing regularly-spaced furrows. These specialized furrowed domains are observed only during periods of gap junction re-organisation (i.e., connexon redistribution) and may reflect the presence of underlying cytoskeletal elements controlling the position of connexons in the membrane.
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    Transendothelial channels in fenestrated endometrial blood capillaries of rats (1984)
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    Cell & tissue research 237 (1984), S. 371-373 
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    ISSN: 1432-0878
    Keywords: Endothelium ; Transport, intracellular ; Transport vesicles, channels ; Micropinocytosis ; Capillaries ; Endometrium ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Three types of transendothelial channels are described in the endothelium of blood capillaries in the endometrium of the rat. It is postulated that they may function as pores draining interstitial fluid to the venous blood.
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    Immunocytochemical demonstration of caldesmon and actin in thyroid glands of rats (1984)
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    Cell & tissue research 237 (1984), S. 375-377 
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    ISSN: 1432-0878
    Keywords: Thyroid ; Immunocytochemistry ; Caldesmon ; Actin ; Endocytosis ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distribution of caldesmon (a calmodulin-binding, F-actin interacting protein; Sobue et al. 1982) and actin was studied in the rat thyroid gland by means of light-microscopic immunocytochemistry, and the fine-structural distribution of actin filaments was examined by use of heavy meromyosin (HMM). Caldesmon and actin were demonstrated in the apical cytoplasm of almost all the follicle epithelial cells in normal as well as TSH-treated animals. Immunoreactivities for both caldesmon and actin showed almost the same pattern in localization. The smooth muscle cells of the blood vessels were also positive for caldesmon and actin. By electron microscopy, numerous actin filaments decorated by HMM and running perpendicularly or randomly to the apical surface were recognized in the apical cytoplasm of the follicle epithelial cell. These results suggest that caldesmon and actin, in conjugation with calmodulin, play a role in the regulation of cellular activity such as exocytosis and endocytosis in the apical portion of the follicle epithelial cell.
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    Structure of the parathyroid glands, as revealed by different methods of fixation (1984)
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    Cell & tissue research 235 (1984), S. 51-58 
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    ISSN: 1432-0878
    Keywords: Parathyroid glands ; Electron microscopy ; Light microscopy ; Quantitative histology ; Mongolian gerbil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Stereology and semi-automatic image analysis were used with the aim of comparing the structure of parathyroid glands from untreated adult Mongolian gerbils fixed by immersion with those fixed by perfusion. Subclassification of the chief cells based upon the staining affinity or electron density of the cytoplasm was readily performed only in glands fixed by immersion, and so-called atrophic cells were observed only in these glands. The atrophic cells were often surrounded by “light” chief cells. In glands fixed by perfusion, “light” chief cells were only rarely encountered. A significant difference between glands fixed by immersion and those fixed by perfusion was found only with regard to the form of cells and nuclei, those fixed by perfusion being more spherical. When comparing individual cells within glands fixed by immersion, “light” chief cells were more spherical and had a significantly larger nuclear and cellular size, and a lower mitochondrial volume density than the “intermediate”/“dark” chief cells. Otherwise there were no significant differences in any of the parameters investigated. These data indicate that occurrence of socalled “light” chief cells and atrophic cells is a result of improper fixation. The results of this study do not favour the concept of a functional cycle with a simultaneous occurrence of active and inactive cells within parathyroid glands.
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    Interdigitating cells in the lymphoid tissues of bovine fetuses and calves (1984)
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    Cell & tissue research 235 (1984), S. 153-158 
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    ISSN: 1432-0878
    Keywords: Bovine ; Interdigitating cell ; Lymphoid tissues ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Electron-microscopic studies of lymphoid tissues from bovine fetuses and from calves disclosed a non-lymphoid cell type in the thymus-dependent zones of secondary lymphoid tissues and in the thymus that is distinguishable from reticulum cells, epithelial and endothelial cells, and macrophages. Based on morphological and topographical criteria, the cell is identified as the interdigitating cell. In addition, studies of the tissues of normal and virus-challenged fetuses, and of conventionally reared calves, indicated that the interdigitating cells originate from monocytoid cells, which undergo differentiation in the thymus-dependent zones during an immune response.
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    Effect of monensin on the Golgi apparatus of absorptive cells in the small intestine of the rat (1984)
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    Cell & tissue research 235 (1984), S. 187-194 
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    ISSN: 1432-0878
    Keywords: Golgi apparatus ; Monensin ; Small intestine ; Cytochemistry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effect of short-time treatment with the ionophore monensin, administered intraluminally at concentrations of 5 and 10 μM, was studied on the Golgi apparatus of absorptive cells in the small intestine of the rat. At 2–3 min after treatment most of the Golgi stacks exhibited dilated cisternae. At 4–5 min stacked cisternae were absent; they were replaced by groups of smooth-surfaced vacuoles. Dilatation and vacuolization occurred in the entire stacks without preferential effect on any particular Golgi subcompartment. Monensin did not influence the cytochemical Golgi reaction of thiamine pyrophosphatase and acid phosphatase. The characteristic staining pattern of these two enzymes in all Golgi cisternae of absorptive cells in the proximal small intestine, and the reactivity restricted to trans cisternae in distal segments of the small intestine, were unchanged after treatment with monensin. In the distal small intestine, the cytochemical pattern allowed the monensin-induced vacuoles to be attributed to the former cisor trans-Golgi face. Further, the cytochemical results demonstrate that vacuolization is not restricted to the stacked cisternae, but includes the trans-most cisterna. The latter, usually located at some distance from the Golgi stacks, has been defined as belonging to the GERL system in several types of cells. The clear response to monensin, an agent that selectively affects the Golgi apparatus, indicates common properties between trans-most and stacked Golgi cisternae.
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    A unique connective tissue structure in the aortic media of the chicken (1984)
    Springer
    Cell & tissue research 235 (1984), S. 215-216 
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    ISSN: 1432-0878
    Keywords: Chicken aorta ; Aortic media ; Connective tissue ; Microtubules ; Filaments
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The interstitium between smooth muscle cells in the media of the abdominal aorta of the chicken contains basement membranes, glycosaminoglycan, stout elastic fibers, extensive bundles of collagenous fibers, and a unique striated structure. In cross section, this striated, hexagonal structure resembles a honeycomb, each hexagon consisting of 6 isosceles triangles. Microtubule-like structures are present at each corner and center of a hexagon, and 3 delicate filaments are located equidistantly between putative microtubules. The periodicity evident in longitudinal section is the result of a constant repetition of microtubule-like elements. From staining with phosphotungstic acid it appears that the striated connective tissue structures are proteinacous and might serve as a reinforcing structure where smooth muscle cells are separated by dilated extracellular spaces.
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    URL: http://dx.doi.org/10.1007/BF00213744
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    The fine structure of identified electrotonic synapses following increased coupling resistance (1984)
    Springer
    Cell & tissue research 235 (1984), S. 243-249 
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    ISSN: 1432-0878
    Keywords: Gap junction ; Electron microscopy ; Freeze fracture ; Cell-to-cell communication
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Gap junctions exist in the septa between the segments of the lateral giant axons in the ventral nerve cord of the crayfish Procambarus. A large increase in the resistance (uncoupling) of these gap junctions was brought about by mechanical injury to the axonal segments. Both thin sections and freeze-fracture preparations were used to monitor the morphological changes which occurred up to 45 min after injury. There was no apparent change in the organization (a loose polygonal array) of the intramembrane particles which make up the junctional complex up to 45 min after injury. In some instances, however, the intramembrane particles appeared to have moved away from the junctional area. Other junctional regions were internalized and appeared similar to what have been called annular gap junctions. Also at this time (20–25 min after injury), a dense cytoplasmic plug formed in uninjured axon near the junctional region. It is concluded that the gap junctions that exhibit a loose polygonal organization of the intramembrane particles may be either in a state of low resistance (coupled) or a state of high resistance (uncoupled).
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    URL: http://dx.doi.org/10.1007/BF00217847
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    Alteration by estrogen of the nucleoli in nerve cells of the rat hypothalamus (1984)
    Springer
    Cell & tissue research 235 (1984), S. 485-489 
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    ISSN: 1432-0878
    Keywords: Ventromedial nucleus ; Hypothalamus ; Ultra-structure ; Nucleoli ; Estrogen effects ; Chromatin ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Estrogen is accumulated from the blood by nerve cells in the ventromedial nucleus of the hypothalamus and can facilitate female reproductive behavior by acting on this region of the brain. This cell group was examined in ovariectomized female rats, given estrogen or control treatment, by use of light and electron microscopy. A significantly greater portion of the nerve cells in the estrogen-treated animals had protuberances on their nucleolar surfaces, apparent under the light microscope. The fine structure of such protuberances included dense, aggregated material, which is shown to contain DNA by the sodium tungstate staining technique. Because increased numbers of such protuberances were found in nuclei of cells of the experimental group where previous studies demonstrated a significant increase in ultrastructural signs of biosynthetic activity, they may be associated with increased RNA synthesis. Thus, they could indicate, ultrastructurally, increased synthetic rates for RNA in nerve cells through which estrogen promotes reproductive behavior.
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    Studies on the morphology of the isolated perfused rabbit ovary (1984)
    Springer
    Cell & tissue research 235 (1984), S. 565-573 
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    ISSN: 1432-0878
    Keywords: Ovulation ; Perfusion ; Graafian follicle (rabbit) ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ovulation was induced in rabbits by intravenous administration of human chorionic gonadotrophin (HCG), and 4–5 h later the ovaries were isolated and introduced into an in-vitro perfusion system containing synthetic medium with albumin. Rupture of follicles occurred in vitro within the physiological time range (mean 11.3 h after injection of HCG), although with a reduced frequency. Preovulatory and ruptured follicles were studied in detail by light and electron microscopy. In the granulosa layer of ruptured or preovulatory follicles cytoplasmic blebbing activity, disappearance of CallExner bodies and differentiation toward luteinized cells were found. Perhaps the most important sign of normal preovulatory development in vitro was that the basement membrane surrounding the granulosa layer was penetrated by projections of granulosa cells. In the absence of this penetration phenomenon the granulosa layer prolapsed out of the follicle. Immediately before rupture, follicles showed marked degeneration, restricted to the outer layers of the apical wall, which is compatible with the hypothesis that degradative enzymes are released close to the surface of preovulatory follicles. Although the majority of follicles that ovulated under in-vitro conditions showed the same kind of morphological alterations as can be seen in vivo, occasional atypical ruptures occurred without any overt signs during perfusion. Also technical manipulations of the perfusion system, e.g., nonphysiological increase of perfusion pressure, could force follicles to rupture. This illustrates the importance of careful morphological study of all ovaries perfused in vitro before conclusions are drawn.
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    Karyometry of nuclei in liver cells (1984)
    Springer
    Cell & tissue research 235 (1984), S. 669-673 
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    ISSN: 1432-0878
    Keywords: Liver-cell heterogeneity ; Hepatic venous branches ; Karyometry ; Binucleate cells ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In untreated adult male albino rats nuclear volume and the percentage of binucleate cells were determined in the first layer of hepatocytes adjacent to hepatic venous branches of varying diameters (〈40 μm, 40 μm–80 μm, 80 μm–120μm, 120 μm–160 μm, 〉160 μm), and in the third and fourth layer of hepatocytes in the remainder of the perivenous parenchyma. In the first layer of hepatocytes adjacent to the vascular structures means of nuclear volume are significantly lower and percentage of binucleate cells significantly higher than in the cells of the remainder of the perivenous parenchyma. Within each area measured distribution curves of nuclear volume classes were homogeneous but showed heterogeneity in comparison with each other. The morphometric data presented in this study strongly support the opinion of the heterogeneity of liver cells in the perivenous zone, as previously postulated on the basis of histochemical investigations.
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    A morphometric study of the variations in subcellular structures of rat hepatocytes during 24 hours (1984)
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    Cell & tissue research 236 (1984), S. 305-315 
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    ISSN: 1432-0878
    Keywords: Hepatocytes ; Rat ; Liver ; Circadian rhythm ; Morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Subcellular structures of hepatocytes in periportal and perivenous zones were examined during 24 h. The volume, surface and numerical profile densities of cytoplasmic organelles were analysed morphometrically. Most subcellular structures in periportal and perivenous hepatocytes were subject to strong circadian variations. In hepatocytes from both zones, the volume densities of smooth endoplasmic reticulum (sER), mitochondria, lysosomes, peroxisomes, polysomes and lipid droplets demonstrated peak values at 16.00 h, 20.00 h or 00.00 h; trough values were at 04.00 h, 08.00 h, or 12.00 h, except for peroxisomes (16.00 h). However, the volume densities of glycogen granules and rough endoplasmic reticulum (rER) in periportal and perivenous hepatocytes exhibited maximal values at 04.00 h, 08.00 h or 12.00 h and minimal values at 20.00 h. The surface densities of sER, mitochondria, lysosomes and peroxisomes, and the numerical profile densities of mitochondria, lysosomes and peroxisomes in periportal and perivenous hepatocytes showed similar trends. These events suggest that membranes of the rER show a partial correlation with the sER, mitochondrial and lysosomal membranes during the 24-h span. This may involve the interaction between ribosomes and rER. Almost all cytoplasmic organelles examined displayed significant differences between periportal and perivenous hepatocytes, morphometrically and in fine structure, indicating that the morphofunctional variability of hepatocytes differs depending on the location in the liver acinus.
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    URL: http://dx.doi.org/10.1007/BF00214231
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    Mitochondrial binding of triiodothyronine (T3) (1984)
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    Cell & tissue research 236 (1984), S. 321-325 
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    ISSN: 1432-0878
    Keywords: Triiodothyronine ; Radioautography ; Mitochondria ; Liver ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary To assess the distribution of the thyroid hormone triiodothyronine (T3) within intact living cells, freshly prepared dispersed rat hepatocytes were incubated with [125I]-T3 for periods of 5 min and 30 min. Lightand electron-microscopic (EM) radioautography was carried out to determine the distribution of grains over the isolated cells. Both procedures showed the grains distributed almost entirely over the cytoplasmic matrix rather than the nucleus. Grain counts under the EM were compared with expectation based on established quantitative methods. Only the mitochondria showed obvious and statistically significant grain counts, whereas the nucleus failed to accumulate grains in excess of expectations by chance alone based on area. The findings support the existence of mitochondrial binding of T3, presumably a prerequisite for its action in direct stimulation of the mitochondria.
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    Intercellular junctions between macrophages in the regional lymph node of the rat after injection of large doses of steroids (1984)
    Springer
    Cell & tissue research 236 (1984), S. 351-355 
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    ISSN: 1432-0878
    Keywords: Lymph node ; Steroids ; Macrophages ; Intercellular junctions ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Intercellular junctions were often found between macrophages in sinuses of regional lymph nodes of the rat after injection of large doses of cholesterol, cortisone acetate, and estrone at the footpad. They were identified by subplasmalemmal densities, 20–50 nm in width, beneath the plasma membranes of apposed macrophages. No distinct filamentous structures were visible in those dense regions. Electron-dense amorphous materials are lined up at the center of the intercellular space in the junctional regions. Some macrophages form clusters with intercellular junctions. No significant difference in the effect of cholesterol, cortisone acetate, and estrone on the number of intercellular junctions betwene macrophages was found.
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    URL: http://dx.doi.org/10.1007/BF00214238
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    Immunocytochemistry and ultrastructure of the neuropil located ventral to the rat supraoptic nucleus (1984)
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    Cell & tissue research 236 (1984), S. 171-180 
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    ISSN: 1432-0878
    Keywords: Immunocytochemistry ; Ultrastructure ; Supraoptic nucleus ; Neuropil ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The neuropil located ventral to the SON was investigated by the use of immunoperoxidase staining for neurophysins, oxytocin and vasopressin, and electron miroscopy. The study was performed in six groups of rats: 1) control; 2) infusion of isotonic saline into the CSF; 3) infusion of hypertonic saline into the CSF; 4) drinking hypertonic saline for 4 days; 5) same as group 4 but injection of colchicine into the CSF on second day of dehydration; 6) salt loading for 3 months. In the control rats the ventral neuropil contained a few immunoreactive processes, the general morphology of which was completely different from that of the neurosecretory axons emerging from the SON at its dorsal aspect. In rats of groups 3 to 6 the ventral processes (VP) became loaded with neurosecretory granules, whereas the perikarya and axons were depleted. Based on their general morphology and reactivity pattern it is suggested that the VP are dendrites. Most of these “dendrites” were embedded in a glial cushion formed by the processes of a particular type of marginal glia. Some of these “dendrites” enveloped an arteriole penetrating the optic tract. All VP were rich in synaptic contacts. The possibility that the VP of neurosecretory cells may be functionally related to the subarachnoid CSF and the arteriolar blood flow is discussed.
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    URL: http://dx.doi.org/10.1007/BF00216528
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    Control of peptide release from cells of the intermediate lobe of the rat pituitary (1984)
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    Cell & tissue research 236 (1984), S. 561-566 
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    ISSN: 1432-0878
    Keywords: Pituitary gland, pars intermedia ; Peptide hormones ; Dopamine ; Corticotropin-releasing hormone ; 6-Hydroxydopamine ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary When rats were injected with 6-hydroxydopamine the catecholaminergic nerve terminals in their intermediate lobes exhibited distinct signs of degeneration. Morphometric examination of the Golgi apparatus in cells of the intermediate lobe of these rats showed significant enlargement of Golgi cisternae. The release of adrenocorticotropin, β-endorphin/lipotropin and α-melanotropin from intermediate-lobe cells in vitro was measured by radioimmunoassay. The high basal peptide release was inhibited by dopamine and stimulated by methyl-isobutyl-xanthine. In contrast, γ-aminobutyric acid, serotonin, histamine and noradrenaline, or corticotropin-releasing hormone, rat hypothalamic extract and vasopressin had no or only very weak effects. These observations indicate that the synthetic apparatus of intermediate-lobe cells is constantly depressed by dopaminergic nerves. We were not able to stimulate peptide release from intermediate-lobe cells by use of the abovementioned endogenous agents.
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    Electron-microscopic investigation of the innervation of the pars distalis of the hypophysis in adult Rana temporaria L. (1984)
    Springer
    Cell & tissue research 237 (1984), S. 149-154 
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    ISSN: 1432-0878
    Keywords: Pituitary gland, pars distalis ; Innervation ; Synaptoid contacts ; Electron microscopy ; Rana temporaria L
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the pars distalis of the hypophysis of adult Rana temporaria, three types of nerve-fiber profiles were found at two distinct sites, in both lateral parts of the bordering regions of the anterior lobe with the intermediate lobe of the hypophysis. The first type of nerve-fiber profile consists of bundles of very fine axonal elements (diameter: 〈0.7 μm). The second type is formed by larger nerve fibers (diameter up to 4 μm) containing a few neurosecretory granules of approximately 100 nm. The third type of nervefiber profile resembles the second type but these nerve fibers make synaptoid contacts on at least two different types of glandular cells. The possible functional significance of these nerve fibers in the pars distalis is discussed. No nerve fibers were found (1) in the central part of the bordering region of the pars distalis with the intermediate lobe, (2) at the bordering region with the median eminence and (3) with the neurohypophysial stalk, and (4) in all other parts of the pars distalis.
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    Effects of prolonged maternal fast on the pancreas of 18–21-day-old foetal rats (1984)
    Springer
    Cell & tissue research 237 (1984), S. 169-179 
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    ISSN: 1432-0878
    Keywords: Foetal pancreas ; β Cells ; Insulin ; Fasting mothers ; Morphometry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary After maternal fasting for 72 h the pancreatic β cells of 18-day-old foetal rats show a conspicuous enrichment in secretory material, with an increase of pancreatic insulin concentration and a marked development of the rough endoplasmic reticulum and the Golgi apparatus. The morphometric analysis shows that the intracytoplasmic migration of the secretory granules is inhibited, principally inside the cell web. Consequently the number of secretory granules fused with plasma membrane decreases and this is associated with a decreased foetal plasma insulin. The difference in the ultrastructural aspect of the β cells of foetuses from fasting mothers and of foetuses from fed mothers is less conspicuous at 19 days of gestation and progressively disappears at 20 and 21 days. The modifications in ultrastructural aspect and in functional state are discussed.
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    Histological study of ibotenic acid-induced modifications of rat retina and their attenuation by diazepam (1984)
    Springer
    Cell & tissue research 238 (1984), S. 81-85 
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    ISSN: 1432-0878
    Keywords: Retina ; Ibotenic acid ; Toxicity ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary After 2 h intraocular injections of 19 and 190 nmoles ibotenic acid in the rat retina produced an intensive vacuolization of the inner plexiform layer and cellular alterations, in the inner nuclear layer and ganglion cell layer. These alterations consisted of either cytoplasmic swelling accompanied by clumping of the nuclear chromatin or darkening of the cytoplasm along with nuclear condensation. A week later the retinas were thinner than the controls due to the disappearance of the affected cells. Pre-treatment with diazepam prevents the morphological alterations induced by 19 nmoles ibotenic acid; mainly the swelling, which was completely prevented, while the darkening was reduced drastically, although some vacuolization of the inner plexiform layer is still present.
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    The effect of an LH pulse on 3H-thymidine incorporation into cultured ovaries of metestrous rats (1984)
    Springer
    Cell & tissue research 238 (1984), S. 159-163 
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    ISSN: 1432-0878
    Keywords: Ovary ; Rat ; Cell division ; Luteinizing hormone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effect of an LH pulse on the rate at which 3H-thymidine is incorporated into cultured ovaries of metestrous rats was studied. In comparison to ovaries cultured with tonic LH, an LH pulse (1) “rescued” follicles from atresia, (2) induced thecal cell proliferation, and (3) increased the rate at which granulosa cells enter mitosis. It is concluded that LH pulses increase follicular growth by first triggering thecal cell proliferation and then inducing mitotic divisions within the granulosa cells of both atretic and non-atretic follicles.
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    Electron-microscopic immunohistochemical study of the localization of immunoglobulin G in the choroid plexus of the rat (1984)
    Springer
    Cell & tissue research 238 (1984), S. 177-182 
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    ISSN: 1432-0878
    Keywords: Choroid plexus ; Immunoglobulin G ; Permeability ; Anti-HRP-IgG ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The localization of autologous antiperoxidase immunoglobulin G (IgG) was studied in the choroid plexus of Lewis rats immunized against horseradish peroxidase (HRP). This experiment was performed to study the permeability of the choroid plexus to intravascular IgG. It was shown that autologous IgG was present in the extravascular spaces. The transendothelial transfer appeared to occur mainly via the fenestrations and some interendothelial junctions. No transfer of IgG at the level of epithelial cells toward the cerebrospinal fluid was demonstrated. Interstitial spaces in contact with the connective-tissue cells of the choroid stroma were strongly labeled. The significance of these spaces remains hypothetical and raises the question of the fate of IgG from the interstitial space.
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    Vascularization and glomerular ultrastructure in the pig mesonephros (1984)
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    Cell & tissue research 238 (1984), S. 165-175 
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    ISSN: 1432-0878
    Keywords: Mesonephros ; Pig embryo ; Glomerulus ; Microvasculature ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Vascularization of the pig mesonephros was investigated in embryos 5–8 cm in length. Vascular injections with microfil were cleared and dissected; corrosion casts were studied under the scanning electron microscope (SEM). Perfusion-fixed tissue was used for SEM and transmission electron microscope (TEM) studies, including freeze-fracture specimens. The branches of one mesonephric artery carry up to 15 glomeruli. Several glomeruli occupy the same arterial branch, with very short afferent arterioles proper. The efferent vessels, frequently 2–5, leave the extensive vascular pole opposite the entering arteriole and split into peritubular capillaries radiating towards the superficial veins. These capillaries form vascular regions in the shape of flattened pyramids. Along its course, one nephron is supplied by vessels derived from 4–7 glomeruli. The nephrons have less vascular contact than in the definitive kidney. The ultrastructure of the single mesonephric vessels matches the metanephric counterparts. Epithelioid cells with renin granules are common in afferent arterioles, larger arteries, and efferent vessels. The lobulated glomeruli are up to 750 μm long and flattened, showing the usual features of podocytes, mesangial cells, and an attenuated endothelium with fenestrations between 50 and 250 μm. It partially retains its own basement membrane. There is no proximal mesangium.
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    Glial fibrillary acidic protein and differentiation of neonatal rat pituicytes in vitro (1984)
    Springer
    Cell & tissue research 238 (1984), S. 191-195 
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    ISSN: 1432-0878
    Keywords: Glial fibrillary acidic protein (GFAP) ; Pituicytes, neonatal ; Development, ontogenetic ; Immunofluorescence ; Organ culture ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The appearance and intracellular localisation of glial fibrillary acidic protein (GFAP) in pituicytes in neural lobe cultures of newborn rats aged 7 to 30 days were investigated by use of the indirect immunofluorescence method. GFAP-immunoreactive cells were observed mostly in the outgrowth zone. GFAP was localised in the perikaryal cytoplasm as well as in pituicyte processes. GFAP-positive pituicytes showed considerable morphological polymorphism. The presence of GFAP — astrocytic marker — in pituicytes in vitro and the evident morphological similarity to cultured astrocytes suggest the astroglial character of these cells.
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    Localization and function of cyclic guanosine monophosphate-phosphodiesterase activity in the retinal rods of the rat by means of a newly developed cytochemical method (1984)
    Springer
    Cell & tissue research 238 (1984), S. 453-457 
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    ISSN: 1432-0878
    Keywords: Cyclic guanosine monophosphate-phosphodiesterase (cGMP-PDEase) ; New cytochemical method ; Retina ; Rods, outer segments ; Light perception ; 5′GMPase ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Cyclic guanosine monophosphate-phosphodiesterase (cGMP-PDEase) activity was studied histo- and cytochemically in the retinal rods of the rat with the use of a newly developed technique. Intense activity of cGMP-PDEase was evenly distributed over the outer segments of the rods. Reaction product was observed on the plasmalemma and on the disk membranes of the outer segments. A weak reaction product occurred also on the plasmalemma of the inner segments; however, no precipitate was found in the perinuclear and synaptic portions of the rod cells. The enzyme activity was strongly inhibited by 2 mM theophilline and by 2 mM 3-isobutyl-1-methylxanthine (IBMX). To confirm the specificity of this new cGMP-PDEase method, the localization of 5′nucleotidase (5′GMPase) was also studied. In contrast to the activity of cGMP-PDEase, the activity of 5′GMPase was distributed on the plasma membrane of the photoreceptor cells extending over a wide range from the synaptic endings in the outer plexiform layer to the tip of the outer segments.
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    The effect of long-term denervation on the ultrastructure of Pacinian corpuscles in the cat (1984)
    Springer
    Cell & tissue research 238 (1984), S. 387-394 
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    ISSN: 1432-0878
    Keywords: Pacinian corpuscles, cat ; Denervation ; Atrophy ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of Pacinian corpuscles of the cat located in the crural region and innervated by the interosseous nerve was studied 1 to 14 months after denervation. Both the Pacinian inner core and capsule remained well preserved one month after denervation. However, the denervated inner cores underwent progressive atrophy and wasting, which resulted in a gradual reduction of the amount of inner-core cells and lamellae, widening of interlamellar clefts, formation of empty spaces in the axial region and a considerable increase in the number of collagen fibrils. In spite of the wasting, the inner core still survived 14 months after denervation, but at least half of its volume became occupied by collagen fibrils which surrounded the remaining inner-core cells and lamellae. Collagen fibrils assembled in the denervated core were markedly thinner than those found in the capsule, as is also the case in normal Pacinian corpuscles. In the capsule, discrete focal degeneration, occasional pyknosis of the innermost capsular cells and macrophage infiltration were observed from the first month after nerve section onward, but the number of capsular layers remained within the normal range (30–40) up to 14 months after denervation.
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    Immunohistochemical study of S-100 protein in the postnatal development of Müller cells and astrocytes in the rat retina (1984)
    Springer
    Cell & tissue research 238 (1984), S. 503-508 
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    ISSN: 1432-0878
    Keywords: S-100 ; Müller cell ; Astrocyte ; Development ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The rat retina was studied by immunohistochemistry with antibody to S-100 protein during the first three postnatal weeks. Immunoreactive astrocytes are first detected subjacent to the inner limiting membrane close to the optic disc. They gradually increase in number and spread toward the ora serrata along the inner surface of the retina as the development proceeds. S-100-immunostained Müller cells are first identified on the 12th postnatal day although their immunoreactivity is much weaker than that of astrocytes at the same stage. This differential intensity of the immunoreactivity of the two cell types facilitates observation of the entire shape of the astrocyte. This characteristic reveals that cellular investments of blood vessels in the inner retina are formed by astrocytic processes whereas those in the outer plexiform layer are derived from processes of Müller cells. The cellular investment becomes complete by the 18th postnatal day.
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    URL: http://dx.doi.org/10.1007/BF00219865
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    Effects of ovariectomy and estradiol administration on the adrenal macrophage system of the rat (1984)
    Springer
    Cell & tissue research 238 (1984), S. 559-564 
    Details
    ISSN: 1432-0878
    Keywords: Adrenal cortex ; Macrophages ; Ovariectomy ; Rat ; Estradiol administration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Macrophages of the adrenal cortex were studied in normal male and female, ovariectomized and estradiol-injected rats. In normal male rats few macrophages with numerous granules were observed in the zona fasciculatazona reticularis border, and in the zona reticularis. Granules, identified as lysosomes, were limited by a single membrane with a heterogeneous matrix; they exhibited acid phosphatase- and aminotriazole-resistant peroxidatic activities. A larger number of macrophages had identical distributions in normal female rats. In ovariectomized and estradiol-injected rats the number and distribution of adrenal macrophages were similar to those in normal females; however, in spayed animals the number of these cells in the zona reticularis was higher than in the other experimental groups. Lysosomes in macrophages of treated animals were more numerous and their contents more complex than in normal male animals. These results indicate that the adrenal macrophage system is stimulated in experimental conditions involving high levels of circulating estrogens.
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    URL: http://dx.doi.org/10.1007/BF00219872
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  • 85
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    Fine structure of the small, granule-containing cells in the superior cervical ganglia of hydrocortisone-treated early postnatal and adult rats (1984)
    Springer
    Cell & tissue research 238 (1984), S. 297-305 
    Details
    ISSN: 1432-0878
    Keywords: Sympathetic ganglion ; Development, ontogenetic ; Corticosteroid treatment ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Hydrocortisone injections into rats on postnatal days 3–9 caused an increase in the number of small granulecontaining cells in the superior cervical ganglia. These cells, corresponding to the small, intensely fluorescent cells, showed an extensive rough endoplasmic reticulum, a large Golgi apparatus and a very large number of granular vesicles. In addition to the granular vesicles, 70–160 nm in diameter, in which the dense core filled most of the vesicle, most cells of the hydrocortisone-injected rats contained also larger granular vesicles, up to 350 nm in diameter, in which the dense core was eccentrically located. A minority of the cells contained only granular vesicles 70–100 nm in diameter, which was the only type seen in the saline-treated control rats. Thirty days after discontinuation of the hydrocortisone treatment, most of the cells with large granular vesicles had disappeared, and only two profiles of such cells were seen on day 40. The other small cells contained only granular vesicles 70–160 nm in diameter, and these cells could not be distinguished from the small granule-containing cells of 40-day-old control rats treated early postnatally with saline. Hydrocortisone treatment, first on days 3–9 and subsequently on days 40–46, caused reappearance of the small granule-containing cells with large granular vesicles up to 350 nm in diameter, the dense core of which was eccentrically located. Hydrocortisone treatment on days 40–46 only was not followed by appearance of such cells in rats treated with saline on days 3–9.
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    URL: http://dx.doi.org/10.1007/BF00217301
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    Compartments and perivascular arrangement of the meninges covering the cerebral cortex of the rat (1984)
    Springer
    Cell & tissue research 238 (1984), S. 459-474 
    Details
    ISSN: 1432-0878
    Keywords: Meningeal compartment ; Perivascular space ; Brain intercellular compartment ; Cerebral cortex ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The intercellular clefts of the brain and the leptomeninges, and the perivascular spaces were studied with reference to the results obtained in a previous study (Krisch et al. 1983). The spatial relationships of these compartments were analyzed at the electron-microscopic level. Horse-radish peroxidase (HRP) was injected into the brain or into the contralateral ventricle. The pattern of distribution of HRP depends on the boundary situation in the individual compartments. The inner and outer pial layers accompany the vessels intruding into the brain. In the Virchow-Robin space the pial funnel obliterates within a short distance. The inner arachnoid layer is continuous with the outer arachnoid layer when it covers the vessels traversing the meningeal space. The perivascular compartment is not in communication with the arachnoid space; moreover, the pial funnel within the Virchow-Robin space is sealed off against the arachnoid space. Thus, blood vessels traversing the meningeal spaces and subsequently penetrating the brain surface are exposed to the common intercellular compartment represented by the intercellular clefts of the brain and the leptomeninges; this compartment does not communicate with the other compartments. The cerebrospinal fluid located in this intercellular compartment is preferentially drained into the upper cervical lymph nodes.
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    URL: http://dx.doi.org/10.1007/BF00219861
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    Peroxidase-positive endothelial cells in rat liver (1984)
    Springer
    Cell & tissue research 238 (1984), S. 635-642 
    Details
    ISSN: 1432-0878
    Keywords: Liver ; Endothelium ; Kupffer cells ; Peroxidase ; Cytochemistry ; Ultrastructure ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Rat liver fixed by perfusion with low glutaraldehyde concentrations was incubated in diaminobenzidine-containing medium to stain for peroxidase. Endogenous peroxidatic activity was found not only in Kupffer cells but also in the endothelial cells lining the sinusoids and central veins. The reaction product was localized in the nuclear envelope and endoplasmic reticulum. The peroxidatic activity in endothelial cells showed a concentration-dependent sensitivity to glutaraldehyde: in liver samples fixed with 0.25% glutaraldehyde, approx. 23% of the sinusoidal endothelial cells and 65% of central vein endothelium were peroxidase-positive; with 0.5% glutaraldehyde, only approx. 8% of the sinusoidal endothelial cells contained detectable amounts of the reaction product; with 1.5% glutaraldehyde all endothelial cells were consistently peroxidase-negative. No peroxidatic activity could be found in liver endothelial cells following isolation by centrifugal elutriation. Endothelial cell peroxidase may possibly be involved in defense responses of liver and/or, as a part of prostaglandin synthase system, in prostanoid production.
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    URL: http://dx.doi.org/10.1007/BF00219882
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  • 88
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    Plastid apportionment and preprophase microtubule bands in monoplastidic root meristem cells ofIsoetes andSelaginella (1984)
    Springer
    Protoplasma 123 (1984), S. 95-103 
    Details
    ISSN: 1615-6102
    Keywords: Microtubules ; Mitosis ; Plastids ; Preprophase Band ; Isoetes ; Selaginella
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Ultrastructural observations on monoplastidic root tip cells ofIsoetes andSelaginella demonstrate two important phenomena associated with preprophasic preparation for mitotic cell division, 1. the preprophase band and 2. precise orientation of the dividing plastid relative to the preprophase band. Both of these phenomena accurately predict the future plane of cell division. The plastid divides in a plane parallel to the spindle and each cell inherits a single plastid which caps the telophase nucleus. When succesive transverse divisions occur, the plastid migrates prior to prophase from a position near an old transverse wall to a lateral position in the cell. The plastid is oriented with its median constriction precisely intersected by the plane of the preprophase band. When a longitudinal division follows a transverse division, the plastid remains in its position adjacent to an old transverse wall where it is bisected by the plane of the longitudinally oriented preprophase band microtubules.
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    URL: http://dx.doi.org/10.1007/BF01283580
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  • 89
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    Helical structures in the cytoplasm of differentiating cells ofMicrasterias thomasiana (1984)
    Springer
    Protoplasma 123 (1984), S. 230-232 
    Details
    ISSN: 1615-6102
    Keywords: Helical structures ; Microtubules ; Micrasterias thomasiana
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Helical structures so far not known inMicrasterias are observed in the cytoplasm of differentiating cells ofMicrasterias thomasiana which were pretreated by a special fixation procedure. The structures measure about 45 nm in diameter and are situated in the area of the postmitotic nucleus and its surrounding microtubule system, sometimes close to different kinds of vesicle. Nature and function of the helical structures are still obscure; a relationship to microtubules is discussed.
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    URL: http://dx.doi.org/10.1007/BF01281171
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  • 90
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    Actin microfilaments are involved in scale formation of the chrysomonad cellSynura (1984)
    Springer
    Protoplasma 123 (1984), S. 203-212 
    Details
    ISSN: 1615-6102
    Keywords: Actin ; Microtubules ; Microfibrils ; Silica scale ; Chrysomonads
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In the first step of scale formation several small vesicles originating from the Golgi fuse to form a large flattened primary vesicle associated with the surface of one plastid. In a second step this vesicle undergoes several morphogenetic events to form the mold of ornamented scales elaborated in the lumen of the scale forming vesicle (SFV). Thick filaments composed of a stack of actin microfilaments (MFs) settle on the membrane of the SFV turned toward the plastid. They are laterally cross-linked to each other and to the SFV membrane and assembled in a horseshoe figure at the place of the future base-plate of the scale. On the center of the vesicle free of actin MF, where the periplastidial endoplasmic reticulum (PER) and the SFV membranes are glued, a protrusion occurs to form a diverticulum which is to become the future hull or the spine of the finished scale. On the external side of the SFV a microfibrillar network covers the surface of the vesicle. Microtubules (MTs) originating near the kinetosomes change their rectilinear course to follow the two longitudinal margins and the diverticulum of the SFV. MTs are not directly attached to the membrane of the SFV but rather through the microfibrillar network. A set of observations suggest that actin MFs have a structural function in maintaining the shape of the vesicle rather than a role in the migration of the SFV on the surface of the plastid. MTs probably play a role in the migration and in the morphogenesis of the SFV in conjunction with microfibrils. Also, the formation of SFVs and silica deposition are compared to that in diatoms.
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    URL: http://dx.doi.org/10.1007/BF01281167
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  • 91
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    Enhanced cellular membrane contrast in a marine alga by Osmium-azole complexes (1984)
    Springer
    Protoplasma 119 (1984), S. 48-54 
    Details
    ISSN: 1615-6102
    Keywords: Electron microscopy ; Marine alga ; Membrane contrast ; Osmium-azole complexes ; X-ray microanalysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Addition of certain heterocyclic nitrogen-carbon compounds to standard osmium tetroxide solutions used as secondary fixative resulted in an enhanced general membrane contrast in cells of the marine algaEmiliania huxleyi (Lohmann) Kamptner. Ultrastructural cell morphology and the contrast distribution were compared between cells treated according to a standard secondary fixation procedure and cells post-fixed when above mentioned heterocyclic compounds were introduced; in both cases some of the ultrathin sections were post-stained. Different compounds were tested: 1,2,4-triazole (TRA), 3-amino-1,2,4-triazole (A-TRA), 5-amino-tetrazole (A-TEA) and 2,4,6-tri-amino-1,3,5-triazine (melamine). The results were interpreted to indicate the possible bonding types arising from interaction of the heterocyclic compounds with osmium tetroxide and with membrane constituents. Interpretations were partly inspired by considerations from coordination chemistry. All above tests which did not include post-staining of thin sections could be performed at alkaline pH, and consequently calcified structures were preserved. The enhanced osmium accumulation at membranes was verified with X-ray microanalysis, which also showed that in the cases where membranes were visibly contrasted, localization of probable sites of intracellular non-crystalline calcium was facilitated.
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    URL: http://dx.doi.org/10.1007/BF01287816
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  • 92
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    Gibberellin stabilizes microtubules in onion leaf sheath cells (1984)
    Springer
    Protoplasma 119 (1984), S. 100-109 
    Details
    ISSN: 1615-6102
    Keywords: Allium cepa ; Cell shape ; Colchicine ; Low temperature ; Gibberellin ; Microtubules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Colchicine and cremart (O-ethyl O-(3-methyl-6-nitrophenyl) N-sec-butylphosphorothioamidate) disrupt microtubules in leaf sheath cells of onion plants (Allium cepa L. cv. Senshu-Chuko) and cause cell swelling to make the basal parts of the plants bulbous. Gibberellin A3(GA3) protects microtubules from disruption by colchicine and cremart and suppresses the swelling caused by them. GA3 also protects microtubules from disruption by low temperature.
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    URL: http://dx.doi.org/10.1007/BF01287822
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  • 93
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    Microtubules and morphogenesis in stomata of the water fernAzolla: An unusual mode of guard cell and pore development (1984)
    Springer
    Protoplasma 122 (1984), S. 108-119 
    Details
    ISSN: 1615-6102
    Keywords: Azolla ; Stomata ; Microtubules ; Preprophase band ; Morphogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A mature stomate of the water fernAzolla consists of a single apparently unspecialized annular guard cell (GC) with two nuclei surrounding an elongated pore aligned longitudinally in the leaf. During development, the guard mother cell develops a preprophase band (PPB) of microtubules (MTs) oriented transverse to the leaf axis. This is followed by a cell plate which fuses with the parental walls at the PPB site. Subsequently only the central part of the cell plate is consolidated, while the parts to either side become perforated and tenuous and may disperse completely, forming a single composite GC. Meanwhile, a dense array of MTs appears along both faces of the central part of the new wall, oriented normal to the leaf surface. Further MT arrays radiate out across the periclinal walls from the region of the consolidated cell plate. Putative MT nucleating sites are seen along the cell edges between these anticlinal and periclinal arrays. Polarized light microscopy reveals cellulose deposition parallel to the periclinal MT arrays. At the same time lamellar material is deposited within the new anticlinal wall. As the GC complex elongates, a split appears in these lamellae creating an initially transverse slit which then opens up to become first circular and ultimately an elongated pore aligned in the long axis of the leaf,i.e., at right angles to the wall in which it originated. The radiating pattern of cellulose microfibrils in the periclinal walls contributes to the shaping of the pore. Elongation at the apical and basal ends of the GC is restricted by longitudinal microfibril orientation, while that at the sides is facilitated by transverse alignment.
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    URL: http://dx.doi.org/10.1007/BF01279443
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    The presence of extended phragmosomes containing cytoskeletal elements in fusiform cambial cells ofFraxinus excelsior L. (1984)
    Springer
    Protoplasma 122 (1984), S. 145-152 
    Details
    ISSN: 1615-6102
    Keywords: Fraxinus excelsior L. ; Dividing fusiform cambial cells ; Phragmosome ; Cytoskeletal elements ; Microtubules ; Cell plate positioning
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Fusiform cambial cells of the ash (Fraxinus excelsior L.), which are strongly elongated and vacuolated, contain a phragmosome which traverses the whole length of the cells during preprophase and karyokinesis and which remains present during cytokinesis until it is integrated in cell plate with adjacent cytoplasm. The phragmosome consists of a thin perforated cytoplasmic layer located in the plane of the future cell plate. Otherwise oriented transvacuolar cytoplasmic layers or strands are not present in these cells. The phragmosome contains cytoskeletal elements, namely microtubules and also microfilament bundles both of which are oriented mainly in longitudinal direction. The phragmosomal microtubules are a new category of microtubules associated with cell division; presumably they guide the centrifugally growing cell plate to the parental cell wall site previously marked by the preprophase band of microtubules.
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    URL: http://dx.doi.org/10.1007/BF01279448
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    The behaviour of kinetochore microtubules during meiosis in the fungusSaprolegnia (1984)
    Springer
    Protoplasma 120 (1984), S. 36-42 
    Details
    ISSN: 1615-6102
    Keywords: Kinetochores ; Mitosis ; Microtubules ; Meiosis ; Saprolegnia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary InSaprolegnia, kinetochore microtubules persist throughout the mitotic nuclear cycle but, whilst present at leptotene, they disappear coincidently with the formation of synaptonemal complexes at pachytene and reform at metaphase I. In some other fungi chromosomal segregation is random in meiosis and non-random in mitosis. The attachment of chromosomes to persistent kinetochore microtubules in mitosis, but not meiosis, inSaprolegnia provides a plausible explanation for such behaviour. At metaphase I each bivalent is connected to the spindle by 2 laterally paired kinetochore microtubules whereas at metaphase II (as in mitosis) each univalent bears only one kinetochore microtubule, thus showing that all kinetochores are fully active at all stages of meiosis.
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    URL: http://dx.doi.org/10.1007/BF01287615
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    Immunofluorescence microscopy of tubulin and microtubule arrays in plant cells. II. Transition between the pre-prophase band and the mitotic spindle (1984)
    Springer
    Protoplasma 122 (1984), S. 45-55 
    Details
    ISSN: 1615-6102
    Keywords: Immunofluorescence ; Microtubules ; Mitosis ; Pre-prophase band
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Changing patterns of tubulin immunofluorescence as onion root meristematic cells progress from a mature pre-prophase band (PPB) stage into mitosis are reported here. The PPB reaches its narrowest profile at maturity and then remains the same width throughout the rest of the transition. Concomitant with continuation of chromatin condensation and nucleolar breakdown, both initiated earlier in pre-prophase, alignment of fluorescent fibers along the nuclear envelope (NE) changes. Perinuclear microtubules (MTs), which were parallel to the PPB or randomly arranged when first seen at earlier stages of pre-prophase, assume the orientation of spindle MTS at late preprophase. They lie close to the NE and follow the nuclear contour, ultimately converging upon two focal points directly at the NE surface. MTs also can be seen traversing the cytoplasm between nucleus and cell periphery. As spindle initiation proceeds, PPB fluorescence intensity decreases and eventually is exceeded by the NE-associated fluorescence. PPB and spindle arrays co-exist briefly in the transition period, with spindle MTs typically aligned perpendicular to both the axis of the PPB and its constituent MTs. Total disappearance of the PPB occurs only after chromosome condensation is complete and the nucleus is contained within a spherical or ellipsoid cage of fluorescent fibers comprised of two non-overlapping half-spindles. Like the fully formed prophase spindle which follows, the incipient spindle is neither barrel-shaped nor fusiform, but rather displays MTs radiating from the poles in a smooth arc.
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    URL: http://dx.doi.org/10.1007/BF01279436
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  • 97
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    Supraoptimal growth-temperature reduces the heat-shock sensitivity of the chrysophycean flagellatePoterioochromonas malhamensis (1984)
    Springer
    Protoplasma 123 (1984), S. 48-56 
    Details
    ISSN: 1615-6102
    Keywords: Dictyosome ; Flagellar root apparatus ; Heat-shock ; Lorica formation ; Microtubules ; Supraoptimal growth-temperature ; Poterioochromonas
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The chrysophycean flagellatePoterioochromonas malhamensis shows some characteristic alterations after a sublethal heat-shock (42
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    URL: http://dx.doi.org/10.1007/BF01283181
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    Biological and biochemical analysis of soils (1984)
    Springer
    Plant and soil 76 (1984), S. 127-137 
    Details
    ISSN: 1573-5036
    Keywords: Adenylate pool ; Biomass volume ; CO2 evolution ; Chitin ; DNA ; Electron microscopy ; Enzymes ; Fluorescent antibody ; Fumigation-respiration ; Fungi Histochemistry ; Imunofluorecence ; Jones-Mollison technique ; Microcosms ; Monoclonal antibodies ; Nitrogen ; Nutrients ; Oxygen consumption ; Phosphorus ; Phytotoxins ; Plate counts ; Rhizobium ; Rhizosphere ; Sulphur ; Xenobiotics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary There is an immense literature on biological and biochemical analyses of soils. Such analyses have revealed the enormous richness of species in soil and their vast range of metabolic potentials and ecological diversity. Accordingly, the approaches used to investigate the soil biota and its biochemistry usually have to be modified or adapted depending upon the purpose of the investigation. Studies of micro-organisms in the soil environment, are complicated because microbial cells are commonly attached to surfaces where they live side-by-side with other populations in consortia usually containing different morphological and physiological types. Such assemblages of organisms cannot be described quantitatively using cultural techniques, such as plate counts, which underestimate both cell numbers and viable biomass. The development of more powerful observational and staining techniques has improved our knowledge of the diverse morphological and biochemical composition of soil micro-communities. Such findings have been amplified at a grosser level by laboratory studies with multi-component systems (microcosms) to mimic field situations and to assess the range of biochemical potentials of microbial consortia. But despite notable advances in analytical methods we are still, with a few exceptions, unable to detect or identify those microorganisms which carry out specific biochemical transformations or determine whether particular cells are alive, dormant or dead at the time of observation. Considerable work has been done to define some of the fundamental ecological attributes of microbial assemblages in soil. Productive work on the metabolic activities of the soil microbiota, specially geochemical transformations of C, N, S and P, has been under way for more than a century. But only in more recent years have more sensitive and reproducible analytical methods become available to measure viable biomass in soil. This will enable some insight to be gained into the role that microbial biomass plays as a labile source and sink for plant nutrients.
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    URL: http://dx.doi.org/10.1007/BF02205573
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    Soil organic matter and structural stability: mechanisms and implications for management (1984)
    Springer
    Plant and soil 76 (1984), S. 319-337 
    Details
    ISSN: 1573-5036
    Keywords: Aggregates ; Aluminium ; Bacterial mucilage ; Binding agents ; Calcium ; Cation bridges ; Complexing agents ; Dispersion ; Electron microscopy ; Electrophoretic mobility ; Fungal hyphae ; Glues Iron ; Management Periodate ; Polysaccharides ; Rhizosphere ; Roots ; Slaking
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The stability of pores and particles is essential for optimum growth of plants. Two categories of aggregates macro- (〉 250 μm) and micro- (〈250 μm) depend on organic matter for stability against disruptive forces caused by rapid wetting. Dispersion of clay particles from microaggregates is promoted by adsorption of complexing organic acids which increase the negative charge on clays. The acids are produced by plants, bacteria and fungi. However, the dispersibility of clay in microaggregates is offset by the binding action of polysaccharides, mainly mucilages produced by bacteria, but also by plant roots and fungal hyphae. The stability of microaggregates is also enhanced by multivalent cations which act as bridges between organic colloids and clays. Macroaggregates are enmeshed by plant roots, both living and decomposing, and are thus sensitive to management, and increase in number when grasses are grown and the soil is not disturbed. Lack of root growth,i.e. fallow, has the opposite effect. Various implications for management of soil structure are discussed.
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    URL: http://dx.doi.org/10.1007/BF02205590
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  • 100
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    Structure-activity relationship of stress-inducing odorants in the rat (1984)
    Springer
    Journal of chemical ecology 10 (1984), S. 1007-1018 
    Details
    ISSN: 1573-1561
    Keywords: Rat ; Rattus norvegicus sp. ; odorants ; stress ; behavior ; open field ; corticosterone ; fox dropping ; ketone ; sulfur ; compounds ; tans ; mercaptoketones ; repellent ; structure-activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The stress for 12 sulfur-containing synthetized volatiles was evaluated in male Wistar rats and compared to that for fox-dropping extract concentrate. Stress behavior was analyzed by quantifying various stress responses in a standard open field and measuring the increase in plasma corticosterone concentration. Nine compounds induced stress—a dihydrothiazole, two cyclic polysulfides, five mercaptoketones, and a mercaptan. For the mercaptoketones, the following structure-activity relationships were observed. Size can vary considerably; the mercapto group can be either alpha or beta and either secondary or tertiary. The keto group is not essential, since a structurally related mercaptan remains active. The mercapto group is essential for activity in mercaptoketones, since conversion to a methyl sulfide resulted in a neutral response. This type of odorant could function as an allomone and may have potential in rat control as an area repellent.
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    URL: http://dx.doi.org/10.1007/BF00987509
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