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  • Immunocytochemistry  (52)
  • AERODYNAMICS
  • Analytical Chemistry and Spectroscopy
  • Animals
  • Life and Medical Sciences
  • Physics
  • Yeast
  • Springer  (82)
  • 1990-1994  (82)
  • 1975-1979
  • 1925-1929
  • 1992  (82)
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  • 1990-1994  (82)
  • 1975-1979
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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Journal of industrial microbiology and biotechnology 9 (1992), S. 229-234 
    ISSN: 1476-5535
    Schlagwort(e): Heat shock protein (HSP) ; Yeast ; Saccharomyces ; Viability ; Thermotolerance ; Ethanol tolerance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Summary Heat shock and ethanol stress of brewing yeast strains resulted in the induction of a set of proteins referred to as heat shock proteins (HSPs). At least six strongly induced HSPs were identified in a lager brewing strain and four HSPs in an ale brewing strain. Four of these HSPs with molecular masses of approximately 70, 38, 26 and 23 kDa were also identified in two laboratory strains ofSaccharomyces cerevisiae. The appearance of HSPs correlated with increased survival of strains at elevated temperatures and high concentrations of ethanol. These results suggest that HSPs may play a role in the ethanol and thermotolerance of yeasts. The properties of these proteins and membrane fatty acids in relation to heat and ethanol shock are being investigated.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Cellular and molecular life sciences 48 (1992), S. 172-178 
    ISSN: 1420-9071
    Schlagwort(e): Yeast ; protein degradation ; ubiquitin conjugating enzymes ; signals for proteolysis ; stress response
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Selective degradation of cellular proteins serves to eliminate abnormal proteins and to mediate the turnover of certain short-lived proteins, many of which have regulatory functions. In eukaryotes a major pathway for selective protein degradation is ATP-dependent and is mediated by the ubiquitin system. This pathway involves substrate recognition by components of a ubiquitin-protein ligase system, covalent attachment of ubiquitin moieties to proteolytic substrates, and subsequent degradation of these conjugates by a multicatalytic protease complex. Recent genetic evidence suggests that the remarkable selectivity of this process is largely controlled at the level of substrate recognition by the ubiquitin ligase system. InSaccharomyces cerevisiae, ubiquitin-conjugating enzymes UBC1, UBC4 and UBC5 have been identified as key components of this highly conserved degradation pathway. Genetic analysis indicates that ubiquitin-dependent proteolysis is essential for cell viability and that UBC4 and UBC5 enzymes are essential components of the eukaryotic stress response.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    ISSN: 1432-041X
    Schlagwort(e): Sea urchin ; Jelly coat ; Accessory cell ; Oogenesis ; Immunocytochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The immunocytochemical localization of the egg-jelly macromolecule, a fucose sulphate glycoconjugate (FSG) that induces the acrosome reaction in spermatozoa, was investigated in ovaries of the sea urchin Hemicentrotus pulcherrimus by use of a polyclonal antibody. The polyclonal antibody reacted with the accessory cells and oocytes in the ovarian lumen. In the accessory cells, evidence of an intense immunohistochemical reaction was observed in many globules of variable density. Products of the specific immunohistochemical reaction were frequently observed in the surface region of oocytes, at a distance from the ovarian wall. At the ultrastructural level, the polyclonal antibody was found to react with the material present in the vacuole-like structures of the globules in the accessory cells. Many gold particles, demonstrating specific immunolabelling, were associated with well-developed microvilli on the vitellogenic oocytes. In the mature oocytes, intense labelling was observed in the jelly coat but not in the vitelline coat. By contrast, oogonia and early oocytes were barely labelled. Quantitative data indicated that the extent of immunolabellings in the surface region of oocytes was very high in the vitellogenic and mature oocytes. In all cases, neither the oocyte cytoplasm nor the subcellular organelles were labelled. These results suggest that FSG is produced by the accessory cells and is deposited initially on the surface of vitellogenic oocytes for the formation of jelly. These findings may provide a new insight into the role of the accessory cells in the reproductive process of the sea urchin.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    ISSN: 1432-0827
    Schlagwort(e): Growth hormone ; Growth hormone receptor ; Odontogenesis ; Bone remodeling ; Immunocytochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary Growth hormone (GH) may regulate tooth formation and bone remodeling associated with tooth eruption. This study reports the distribution of growth hormone receptor/binding protein in developing rat molars and adjacent alveolar bone by immunocytochemistry using well-characterized anti-growth hormone receptor monoclonal antibodies. These tissues represent an excellent model for studying the ontogenic changes that occur in odontogenic and osteogenic cells, as these cells are found in linear arrays displaying the various stages of morphological and functional differention, and differentiated function. Immunoreactivity was first seen in precementoblasts in contact with the epithelial root sheath, and preodontoblasts. However, growth hormone receptor immunoreactivity was associated primarily with the cytoplasm of odontogenic and osteogenic cells forming their respective matrices. Thus, cementoblasts and odontoblasts at sites of new matrix formation showed intense immunoreactivity whereas cementocytes and mature odontoblasts at later stages of tooth development were nonreactive. Osteoblasts engaged in intramembranous ossification in the alveolar bone were positive, although osteocytes and endosteal cells were immunonegative. Osteoclasts at sites of alveolar bone remodeling resorption were also immunopositive. These patterns of receptor expression parallel the ontogenic sequences of odontogenic and osteogenic cells and suggest that GH promotes the functional state of these cells. Our results also imply that GH may influence differentiation or differentiated functions associated with odontogenesis, osteogenesis, and bone remodeling independent of systemic insulin-like GF-I.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Sexual plant reproduction 5 (1992), S. 89-100 
    ISSN: 1432-2145
    Schlagwort(e): Actin ; Cytoskeleton ; Generative cell ; Immunocytochemistry ; Microtubule ; Mitosis ; Phragmoplast ; Pollen ; Rhodamine phalloidin ; Sperm
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Disagreement has arisen over the presence of actin-containing microfilaments (Mfs) in angiosperm generative cells and sperm (GSP). In order to address this issue, we subjected GSP of Tradescantia virginiana, Nicotiana tabacum and Rhododendron laetum to a series of localizations using different antiactins, rhodamine phalloidin and antimyosin. Coordinate staining with antitubulin and Hoechst 33258 defined the status of the microtubule (Mt) cytoskeleton and stages of generative cell division. Additional experiments utilized cytochalasin D (CD). In no instance could Mfs be detected in GSP of the three species. Instead, Mfs seen at the periphery of GSP appear to be continuous with vegetative Mfs and thus are in the vegetative cytoplasm. Mfs are not seen in the constriction zone of dividing T. virginiana generative cells, nor are they indicated in the phragmoplast of N. tabacum and R. laetum. Myosin localizations reveal punctate staining in the vegetative cytoplasm and a thin line of fluorescence around the the outside of the generative cell. While CD seems to delay generative cell division, cytokinesis still takes place. CD-induced Mf fragments are evident in the vegetative cytoplasm but not in GSP. The weight of evidence therefore indicates that GSP do not contain Mfs. The implications of this conclusion for the behavior of GSP and the mechanism of cytokinesis in dividing generative cells are considerable.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    ISSN: 1432-0983
    Schlagwort(e): Yeast ; Mitochondria ; Cytochrome oxidase
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary We have analyzed a mutation in the mitochondrial gene oxi3 coding for subunit I of cytochrome-oxidase in the yeast Saccharomyces cerevisiae. This mutation replaces one of the seven invariant histidines of the polypeptide (position 378) by a tyrosine, and leads to a respiratory deficient phenotype. A total of 157 revertants, which have recovered the ability to grow on a respiratory substrate, have been selected from this mutant (tyrosine 378). The nature of the reversion has been analysed by a rapid screening procedure and 32 of the revertants have been sequenced. They are all true backmutations reintroducing the histidine in position 378. This very exceptional situation suggests that this histidine is a ligand of the redox center of cytochrome oxidase.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    ISSN: 1432-0983
    Schlagwort(e): Yeast ; DNA-polymerase α ; Cell cycle
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The 5′ ACGCGT3′ MluI motif, which is found in the upstream region of several yeast DNA-synthesis genes which are periodically expressed during the mitotic cell-cycle, is present twice in the 5′ non-coding region of the DNA-polymerase α gene (POL1). Deletion, of the most distal repeat does not affect POL1 transcription, while the adjacent 40 base-pair (bp) downstream sequence is necessary both for the proper level and the fluctuation of POL1 mRNA. This region contains the 5′ACGCGTCGCGT3′ sequence, which is sufficient to control periodic transcription of a CYC1-lacZ reporter gene with the same kinetics observed for POL1. The adjacent 29 bp AT-rich region does not show any activity by itself, but it acts synergistically in conjunction with at least one MluI hexamer to stimulate CYC1-lacZ expression. By further deletion analysis, DNA sequences necessary to initiate POL1 transcription at the proper sites have also been identified.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 21 (1992), S. 203-206 
    ISSN: 1432-0983
    Schlagwort(e): Yeast ; Galactokinase ; Mutant selection
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The galactose analogue 2-deoxy-galactose (2DG) has been widely used to select for mutations in the gene encoding the galactose pathway enzyme galactokinase (GalK). We have tested the effect of 2DG on Candida albicans to see if it could be used to obtain GalK- mutants in this diploid asexual yeast. 2DG was shown to be toxic to wild-type cells. Enzyme assays demonstrated that 2DG can induce GalK as efficiently as galactose. Examination of the initital rate of galactose uptake indicated that the galactose transport system is constitutive. 2DG-resistant mutants were isolated from mutagenized cultures and shown to have very low levels of GalK activity. The potential genetic applications of this system of direct mutant selection are discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    ISSN: 1432-0983
    Schlagwort(e): Repressor ; Zinc finger ; Leucine zipper ; GATA-1 ; Yeast
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The UGA43 gene of Saccharomyces cerevisiae is required for repression of inducible genes involved in the utilization of 4-aminobutyric acid (GABA) or urea as nitrogen sources. The UGA43 gene has been cloned by complementation of a uga43 mutation. The N-terminal region of the UGA43 protein is very similar to the DNA-binding zinc-finger region typical of the GATA regulatory factor family in vertebrates. UGA43 is the first reported instance of a GATA protein with a negative regulatory function. The C-terminal region of the predicted UGA43 protein contains a putative leucine zipper. Sequencing of three uga43 mutant alleles suggests that the GATA and putative leucine-zipper regions are both required for the repressive activity of UGA43. UGA43 appears to be a highly regulated gene. On “poor” nitrogen sources, UGA43 transcripts are measured at high levels whereas they are nearly undetectable in conditions of nitrogen catabolite repression. The levels measured on “poor” nitrogen sources are further increased in uga43 mutant cells, suggesting that UGA43 exerts negative autoregulation.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    ISSN: 1432-0983
    Schlagwort(e): Yeast ; cAMP ; RAS ; GAP
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The ccs1-1 mutation of Saccharomyces cerevisiae, which has been previously described, is associated with an increase in cytochrome content, in respiration, and in ATP synthesis. In addition, this mutation leads to the same phenotype as cells de-regulated in the cAMP pathway. From a yeast genomic library, we have isolated a DNA fragment in a recombinant plasmid pCD1 which complements the ccs1-1 mutation. Homologous integration of this DNA in the genome occurs at the CCS1 locus. An 11 kb of the DNA insert is necessary for complementation. Sequencing part of the fragment identifies CCS1 as the IRA2 gene. The IRA2 gene is known to encode an attenuator of RAS gene product activity which stimulates the GTPase activity of the RAS proteins. This result underlines the involvement of cAMP-dependent phosphorylation in mitochondrial function. We present the sequence of 1 kb DNA upstream of the putative ATG of the IRA2/CCS1 gene product which is devoid of an ORF and could contain several regulatory sites.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 11
    ISSN: 1432-0983
    Schlagwort(e): Yeast ; Mitochondria ; Aminoacyl-tRNA synthetase ; RNA splicing
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The mitochondrial leucyl-tRNA synthetase (mLRS) of Saccharomyces cerevisiae is involved in both mitochondrial protein synthesis and pre-mRNA splicing. We have created mutations in the regions HIGH, GWD and KMSKS, which are involved in ATP-, amino acid-and tRNA-binding respectively, and which have been conserved in the evolution of group I tRNA synthetases. The mutants GRD and NMSKS have no discernible phenotype. The mutants AWD and ARD act as null alleles and lead to the production of 100% cytoplasmic petites. The mutants HIGN, NIGH and KMSNS are unable to grown on glycerol even in the presence of an intronless mitochondrial genome and accumulate petites to a greater extent than the wild-type but less than 40%. Experiments with an imported bI4 maturase indicate that the lesion in these mutations primarily affects the synthetase and not the splicing functions.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 12
    ISSN: 1432-0983
    Schlagwort(e): Yeast ; 2 μm plasmid ; Mitotic recombination ; Coincident conversion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The influence of the 2 μm plasmid on homologous recombination in the right arm of chromosome XV of the yeast Saccharomyces cerevisiae has been examined. No differences between spontaneous mitotic recombination rates in [cir 0] and [cir +] derivatives of two yeast diploid tester strains were detected. In the course of analysis an unusually high coincident conversion frequency at ADE2, HIS3, and two RFLP loci adjacent to ADE2, was observed. The character of coincident homozygotization of linked markers argues for a “break-and-replicate” mechanism underlying the coincident conversion events.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 13
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 22 (1992), S. 277-282 
    ISSN: 1432-0983
    Schlagwort(e): Yeast ; DNA-repair ; Mutation-deficient mutant ; Nucleotide-binding consensus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The REV2 gene of Saccharomyces cerevisiae was cloned and sequenced; it contains an open reading frame of 1985 bp with a coding potential of 662 amino acids. Interruption of the chromosomal REV2 gene by integrating the URA3 gene coupled with partial deletion of the 3′ terminal region produced viable haploid rev2Δ mutants. This indicates that the REV2 gene is non-essential for growth. The rev2Δ mutant is slightly more UV-sensitive than strains carrying various rev2 alleles (rev2-1, rev2x, rad5-1, rad5-8). The putative Rev2 protein is probably a globular protein containing a highly conserved nucleotide-binding site and two zinc-finger domains.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 14
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 22 (1992), S. 335-336 
    ISSN: 1432-0983
    Schlagwort(e): Yeast ; Rapid transformation ; Cell age
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary We present a simplified and rapid method for the transformation of yeast cells by electroporation. Stationary cells, scraped off the agar of Petri dish cultures stored in the refrigerator for up to 6 weeks, are suspended in sorbitol buffer, spun down by gentle centrifugation, transferred into the electroporation cuvette, and immediately subjected to transformation via electroporation. Transformation efficiency of this 10-min method, which does not require the preparation of cell cultures, is about 10% of the hitherto best performing transformation procedure using cells of defined growth phase.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 15
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 21 (1992), S. 241-247 
    ISSN: 1432-0983
    Schlagwort(e): Yeast ; Transcription ; Mitochondria ; RNA
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary In yeast (S. cerevisiae) the stringent response is known to include rapid, selective, and severe transcriptional curtailment for genes specifying cytoplasmic rRNAs and r-proteins. We have shown that transcription of the mitochondrial 21S rRNA gene is also congruently and selectively curtailed during the yeast stringent response. Using an in vitro transcription assay with intact organelles from both ϱ+ and ϱ− strains, we show here that the mitochondrial stringent response includes not only transcription of the 21S and 16S rRNA genes, but also that of organellar genes specifying non-mitoribosome-related products. Stringent organellar transcriptional curtailment is identical when cells are starved for a required (marker) amino acid or when they are subjected to nutritional downshift, and the relative level of that transcriptional curtailment following either perturbation is the same in cells growing on fermentative (repressing) or purely respiratory carbon sources. These results confirm that the mechanism governing mitochondrial gene expression during a stringent response is specified outside the organelle, and they show that this transcriptional control mechanism is not immediately subject to glucose repression. In all strains examined, stringent organellar gene expression requires a mitochondrial promoter, suggesting that the regulatory mechanism which functions during the stringent response operates primarily at transcriptional initiation.
    Materialart: Digitale Medien
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  • 16
    ISSN: 1432-0983
    Schlagwort(e): Yeast ; Cadmium resistance ; Metallothionein gene ; CUP 1
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary A cadmium-resistant strain of Saccharomyces cerevisiae produces a cadmium metallothionein with the same characteristics as the copper metallothionein that is encoded by CUP 1 in a copper-resistant strain. The structural gene for metallothionein from the cadmium-resistant strain resembles CUP 1 in terms of the fragmentation patterns generated by restriction enzymes. Furthermore, the gene may be amplified as 2.0 kb repeating units in both the cadmium-resistant and the copperresistant strains. However, transformants with a plasmid that carried the metallothionein gene from the cadmiumresistant strain were resistant to copper but not to cadmium. It appears that the same metallothionein gene, CUP 1, is amplified in both cadmium- and copper-resistant yeasts. However, the mechanism for the cadmiumspecific inducibility of the gene may be restricted to the cadmium-resistant strain.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 17
    ISSN: 1432-0983
    Schlagwort(e): Drug resistance ; Yeast ; Positive activator
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The network of genes which mediates multiple drug resistance in yeast includes, among others, the PDR1 gene, which encodes a putative regulator of gene expression, and PDR5, a locus whose amplification leads to resistance. We demonstrate that disruption of PDR5 causes marked hypersensitivity not only to cycloheximide but also to sulphometuron methyl and the mitochondrial inhibitors chloramphenicol, lincomycin, erythromycin and antimycin. Genetic analysis of double mutants containing an insertion in PDR5 (pdr5:Tn5), which renders cells hypersensitive to cycloheximide, and a pdr1 mutation, which confers resistance to this inhibitor, indicates that the expression of resistance requires a functional PDR5 gene. The same interdependency is observed for chloramphenicol, but not for oligomycin, lincomycin, crythromycin or sulphometuron methyl. Northern analysis of PDR1 and PDR5 transcripts reveals that the 5.2 kbp PDR5 transcript is overexpressed in pdr1 (resistant) mutants, but underexpressed in a disruption of PDR1. These observations provide strong experimental support for our former proposal that the PDR5 gene is a target for regulation by the PDR1 gene product.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 18
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 21 (1992), S. 83-84 
    ISSN: 1432-0983
    Schlagwort(e): Yeast ; Transformation ; Thio compound ; Stationary phase
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary A fast yeast-transformation technique has been developed by adding thio compounds to alkali-ion based protocols and incubating at 45°C. This procedure is especially recommended for cells from stationary phase at a density up to 2.5×108 cells/ml. It involves only one step for the preparation and transformation of competent cells within 30 min. The yield was more than 104 transformants/μg plasmid DNA. This protocol is easy to scale up for many DNA samples and is also applicable for yeast cells from different types of storages.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 19
    ISSN: 1432-0983
    Schlagwort(e): Transcription ; Recombination ; Yeast ; Gene conversion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Several investigators have reported that transcription stimulates some types of mitotic recombination in the yeast Saccharomyces cerevisiae. We find that mutations that reduce the rate of trancription of the yeast HIS4 gene in vegetative cells reduce the frequency of mitotic, but not meiotic, recombination events.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 20
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 21 (1992), S. 309-318 
    ISSN: 1432-0983
    Schlagwort(e): Yeast ; Aneuploidy ; Chromosomes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The arg4–8 and cup1 s markers comprise a copy-number-dependent signal device in the yeast Saccharomyces cerevisiae. These alleles permit reliable discrimination between euploid and disomic haploids as well as between euploid and trisomic diploids. To investigate and compare inherent inter-chromosomal differences as regards propensity for hyperploidy, we transplaced arg4–8 and cup1 s by deleting them from chromosome VIII and then re-introducing them at the leu2 locus on chromosome III. The rate of chromosome gain was significantly greater for the chromosome III construct compared to the native chromosome VIII, in both diploid and haploid strains. In addition, more coincident aneuploidy for other chromosomes was found among chromosome VIII hyperploids compared to chromosome III hyperploids.
    Materialart: Digitale Medien
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  • 21
    ISSN: 1432-0983
    Schlagwort(e): Yeast ; Saccharomyces cerevisiae ; Lysis mutants ; Plasmid stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The autonomously replicating plasmid YEpSS1, containing the S. cerevisiae SOD1 and SRB1 genes, was highly unstable in a wild-type strain. When transformed into a fragile srb1-1 mutant host, the same plasmid displayed different characteristics depending on the growth medium used. Both batch and continuous culture experiments demonstrated that the plasmid was very unstable when the transformed strain SLU15 was grown in the presence of an osmotic stabiliser (10% w/v sorbitol). However, in the absence of the osmoticum, nearly 100% of the cells retained the plasmid and produced the Sod1 protein after 80 generations of growth.
    Materialart: Digitale Medien
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  • 22
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 22 (1992), S. 13-19 
    ISSN: 1432-0983
    Schlagwort(e): Chromosome length variants ; Adaptation ; Yeast ; Continuous culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Thirteen independent populations of Saccharomyces cerevisiae (nine haploid and four diploid) were maintained in continuous culture for up to approximately 1000 generations, with growth limited by the concentration of organic phosphates in medium buffered at pH 6. Analysis of clones isolated from these populations showed that a number (17) of large-scale chromosomallength variants and rearrangements were present in the populations at their termination. Nine of the 16 yeast chromosomes were involved in such changes. Few of the changes could be explained by copy-number increases in the structural loci for acid phosphatase. Several considerations concerning the nature and frequency of the chromosome-length variants observed lead us to conclude that they are selectively advantageous.
    Materialart: Digitale Medien
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  • 23
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 22 (1992), S. 175-180 
    ISSN: 1432-0983
    Schlagwort(e): ARS1 mutants ; DNA replication ; Yeast ; Single-stranded DNA
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary A naturally occurring single base-pair G to A transition, creating a 10/11 near-match close to the essential 11 base-pair core consensus of ARS1, was used to investigate the importance of near-match sequences. The 10/11 near-match can not substitute for the core consensus since an ARS- phenotype is observed when the core consensus is deleted. However, deletion mutations revealed that this near-match together with a short palindromic sequence, also situated in the B-flanking region, comprise a single element crucial for optimal ARS function. The palindrome has the potential of forming a stemloop structure. Rather precise observations concerning the borders of the B-region were achieved. The four base pairs separating the near-match from the core consensus perform a spacing function where the identity of the bases are unimportant. However, this spacing is highly important since deletion of these four base pairs leads to an ARS- phenotype.
    Materialart: Digitale Medien
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  • 24
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 157 (1992), S. 218-222 
    ISSN: 1432-072X
    Schlagwort(e): Denitrification ; N2O reductase ; Nitrite reductase ; Immunocytochemistry ; Localization ; Two-dimensional electrophoresis ; Cell fractionation ; Pseudomonas stutzeri
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Immunogold labelling techniques on ultrathin sections of low temperature embedded cells yielded evidence for the periplasmic location of the respiratory enzymes N2O reductase and nitrite reductase (cytochrome cd 1) in Pseudomonas stutzeri strain ZoBell. Cell fractionation by spheroplast preparation and two-dimensional electrophoresis showed the absence of a membrane association of these enzymes. Immunocytochemical localization of N2O reductase in a mutant strain deficient in the chromophore of N2O reductase showed the gold label at the cell periphery, indicating that the copper chromophore processing takes place after export of this protein's apoform.
    Materialart: Digitale Medien
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  • 25
    ISSN: 1476-5535
    Schlagwort(e): Heat shock ; Ethanol ; Saccharomyces ; Yeast ; Fermentation ; Viability ; Wort
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Summary The effects of heat shock and ethanol stress on the viability of a lager brewing yeast strain during fermentation of high gravity wort were studied. These stress effects resulted in reduced cell viability and inhibition of cell growth during fermentation. Cells were observed to be less tolerant to heat shock during the fermentation of 25°P (degree Plato) wort than cells fermenting 16°P wort. Degree Plato (oP) is the weight of extract (sugar) equivalent to the weight of sucrose in a 100 g solution at 20°C. Relieving the stress effects of ethanol by washing the cells free of culture medium, improved their tolerance to heat shock. Cellular changes in yeast protein composition were observed after 24 h of fermentation at which time more than 2% (v/v) ethanol was present in the growth medium. The synthesis of these proteins was either induced by ethanol or was the result of the transition of cells from exponential phase to stationary phase of growth. No differences were observed in the protein composition of cells fermenting 16°P wort compared to those fermenting 25°P wort. Thus, the differences in the tolerance of these cells to heat shock may be due to the higher ethanol concentration produced in 25°P wort which enhanced their sensitivity to heat shock.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 26
    ISSN: 1432-1890
    Schlagwort(e): Ericaceae ; Mycorrhizal fungi ; Acid phosphatase ; Protein expression ; Immunocytochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The activity of acid phosphatase produced in pure culture by the endomycorrhizal fungus Hymenoscyphus ericae (Read) Korf & Kernan (H. ericae LPA 2) was inhibited by high phosphorus levels, alkaline pH, fluoride, molybdate and mannosidase, and activated by concanavalin A. Over 80% of the enzyme activity was due to two wall-bound acid phosphatase isozymes with the characteristics of mannose-rich glycoproteins. Antiserum was raised against the major, low-molecular-weight wall isozyme and its activity tested by immunoblotting and ELISA. The antiserum cross reacted 100% with exocellular (excreted) and 28% with cytoplasmic cellular fractions of H. ericae (LPA 2) cultures, and showed high reactivity with other strains of H. ericae but not with fungal isolates from Erica hispidula L. or E. mauritanica L. Ultrastructural localization of acid phosphatase by cytoenzymology and indirect immunogold labelling confirmed its association with the fungal wall in pure culture and showed that the influence of a high phosphorus level, fluoride and molybdate is through inactivation of the enzyme. Intense acid phosphatase activity, sensitive to the latter inhibitors, was also present on external hyphae growing over a host or non-host root but it was weak or absent from intracellular hyphae where these developed within a host root. Indirect immunolabelling confirmed that this acid phosphatase was of fungal origin and that the specific inhibitory effect of host cells is due to inactivation of the enzyme rather than repression of its synthesis. Possible implications of fungal acid phosphatase in ericoid endomycorrhizal infection processes are discussed together with mechanisms that may be regulating the enzyme activity.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 27
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 270 (1992), S. 395-404 
    ISSN: 1432-0878
    Schlagwort(e): Nucleus sacci vasculosi ; Ultrastructure ; Immunocytochemistry ; Hypothalamus ; Tuberculum posterius ; Scyliorhinus caniculus, Raja undulata (Elasmobranchii)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The elasmobranch nucleus sacci vasculosi was studied by means of electron microscopy (in the dogfish) and immunocytochemistry (in the dogfish and the skate) by using antibodies against tyrosine hydroxylase, alpha-melanocyte-stimulating hormone, somatostatin, serotonin, and substance P. Ultrastructural study of the dogfish nucleus sacci vasculosi shows the presence of medium-sized cells that possess numerous mitochondria but that have no dense-core vesicles in the cytoplasm or in cell processes. Fibres of the conspicuous tractus sacci vasculosi have a beaded appearance and form conventional synapses with dendrites and cell perikarya of the nucleus sacci vasculosi. The perikarya of this hypothalamic nucleus were not immunoreactive to any of the antibodies tested, and fibres immunopositive to tyrosine hydroxylase, alpha-melanocyte-stimulating hormone, somatostatin, serotonin, and substance P were scarce within this nucleus, in both the dogfish and the skate. Dorsal to the nucleus sacci vasculosi, there are numerous positive neuronal processes in addition to many small neurons that show immunoreactivity to alpha-melanocyte-stimulating hormone, somatostatin and tyrosine hydroxylase. Two types of neuron occur in this dorsal region, displaying dense-core vesicles of either 100–160 nm or 60–100 nm diameter in their cytoplasm; they were identified as peptide-containing and monoamine-containing neurons, respectively. The neuropil of this region has a significantly different ultrastructure from that of the nucleus sacci vasculosi, with many processes containing dense-core vesicles. This group of neurons, located dorsal to the nucleus sacci vasculosi and showing (a) immunoreactivity to neuropeptides or to monoamine-synthesizing enzyme, and (b) cytoplasm with dense-core vesicles, was considered not to be a part of the nucleus sacci vasculosi but rather part of the nucleus tuberculi posterioris. These results support the non-peptidergic and non-aminergic character of the nucleus sacci vasculosi.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 28
    ISSN: 1432-0878
    Schlagwort(e): Serotonin ; Whole-mount ; Immunocytochemistry ; Insect ventral nervous system ; Interneurons ; Efferent neurons ; Leptinotarsa decemlineata (Insecta)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary In an immunohistochemical study of the ventral nerve cord of L. decemlineata, five distinct neuron categories were distinguished: 1) Two paired segmental twin interneurons occur in each ganglion or neuromere; their axons distribute processes over almost the entire nerve cord and run to the cerebral ganglion complex. In contrast, other axons are distributed locally. 2) Four large frontal neurosecretory neurons occur in the suboesophageal ganglion (SOG), two of which have axons that run into the mandibular nerves to form a neurohemal plexus on the surface of cerebral nerves. 3) A pair of large caudal neurons occur in the terminal ganglion and innervate the hindgut. 4) Local miniature interneurons occur in the SOG. 5) Terminal neurons are present in the last abdominal ganglion. Segmental twin interneurons appear to be grouped into 3 ‘functional units’ spanning several ganglia. Their axons run to specific projection areas, which separate the functional units, and which mark the externally visible separation of condensed ganglion complexes. A possible role of the most caudal functional unit might be the synaptic control of caudal neurons innervating the hindgut.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 29
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 270 (1992), S. 469-474 
    ISSN: 1432-0878
    Schlagwort(e): Pericytes ; Angiogenesis ; Capillaries ; Capillary sprouting ; Desmin ; Immunocytochemistry ; Rat Adenocarcinoma cells, rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary To investigate the participation of microvascular pericytes in the process of capillary sprouting, we examined whole-mount preparations of the rat mesentery by use of a double immunofluorescence approach. Angiogenesis was induced by intraperitoneal injections of either the mast cell-degranulating substance compound 48/80 or tumor cell-conditioned medium. Capillary sprouts were visualized by staining with rhodaminconjugated phalloidin and pericytes were simultaneosly stained by an antibody to the intermediate filament protein desmin. Developing pericytes were negative for the smooth-muscle isoform of α-actin, bbut were clearly reactive for desmin. Pericytes appear to be involved in the carliest stages of capillary sprouting. Pericytes were regularly found lying at and in front of the advancing tips of endothelial sprouts. At many sites pericytes were seen to bridge the gap between the leading edges of opposing endothelial sprouts, which were apparently preparing to merge, suggesting that pericytic processes may serve as guiding structures aiding outgrowth of endothelial cells.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 30
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 267 (1992), S. 125-130 
    ISSN: 1432-0878
    Schlagwort(e): Sensory ganglia ; Sympathetic ganglia ; Parasympathetic ganglia ; Basic fibroblast growth factor ; Substance P ; Somatostatin ; Bombesin ; Immunocytochemistry ; Rat (Wistar: Han)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The distribution of basic fibroblast growth factor (bFGF)-immunoreactivity (IR) was studied in rat sensory and autonomic ganglia. In postnatal and adult sympathetic superior cervical ganglia and in adult parasympathetic otic ganglia no bFGF-staining was found. Postnatal and adult neural crest-and placode-derived sensory ganglia displayed intensive bFGF-IR in a neuronal subpopulation. This subpopulation was characterized by use of consecutive sections of adult dorsal root ganglia stained with antibodies against substance P, somatostatin, bombesin, and bFGF. Basic FGF was colocalized with the somatostatin/bombesin subpopulation but not with substance P.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 31
    ISSN: 1432-0878
    Schlagwort(e): Dopamine ; Tyrosine hydroxylase ; Histamine ; Immunocytochemistry ; Insect nervous system ; Drosophila melanogaster, Phormia terraenovae, Calliphora erythrocephala (Insecta)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The distribution and morphology of neurons reacting with antisera against dopamine (DA), tyrosine hydroxylase (TH) and histamine (HA) were analyzed in the blowflies Calliphora erythrocephala and Phormia terraenovae. TH-immunoreactive (THIR) and HA-immunoreactive (HAIR) neurons were also mapped in the fruitfly Drosophila melanogaster. The antisera against DA and TH specifically labeled the same neurons in the blowflies. About 300 neurons displayed DA immunoreactivity (DAIR) and THIR in the brain and subesophageal ganglion of the blowflies. Most of these neurons were located in bilateral clusters; some were distributed as bilateral pairs, and two ventral unpaired median (VUM) neurons were seen in the subesophageal ganglion. Immunoreactive processes were found in all compartments of the mushroom bodies except the calyces, in all divisions of the central body complex, in the medulla, lobula and lobula plate of the optic lobe, and in non-glomerular neuropil of protocerebrum, tritocerebrum and the subesophageal ganglion. No DA or TH immunoreactivity was seen in the antennal lobes. In Drosophila, neurons homologous to the blowfly neurons were detected with the TH antiserum. In Phormia and Drosophila, 18 HA-immunoreactive neurons were located in the protocerebrum and 2 in the subesophageal ganglion. The HAIR neurons arborized extensively, but except for processes in the lobula, all HAIR processes were seen in non-glomerular neuropil. The deuto- and tritocerebrum was devoid of HAIR processes. Double labeling experiments demonstrated that TH and HA immunoreactivity was not colocalized in any neuron. In some regions there wasm however, substantial superposition between the two systems. The morphology of the extensively arborizing aminergic neurons described suggests that they have modulatory functions in the brain and subesophageal ganglion.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 32
    ISSN: 1432-0878
    Schlagwort(e): Fetal intermediate lobe ; Tissue culture ; Immunocytochemistry ; In situ hybridization ; Dopamine ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Organotypic cultures, in defined medium, of pituitary primordia obtained from 15-day-old rat fetuses were performed in order to study the in vitro differentiation of melanotrophic cells. The morphological and ultrastructural features of the transplants resembled those of the gland developing in vivo. In situ hybridization on semi-thin sections, using a 35S-labelled oligonucleotide probe, revealed pro-opiomelanocortin-mRNA-containing cells on the first day of culture in the anterior lobe and after 2–3 days in the intermediate lobe. Immunoperoxidase labelling of adjacent sections showed that the same cells reacted with antibodies against α-melanocyte-stimulating hormone (αMSH), γ3 and adrenocorticotropic hormone in both lobes. The pro-opiomelanocortin-mRNA-containing cells formed progressively conspicuous areas in the intermediate lobe, which was almost uniformly labelled after 6 days. In the anterior lobe, these cells remained scattered in small cell groups, and colloidal gold immunolabelling showed the progressive disappearance of αMSH labelling from the secretory vesicles in cells exhibiting morphological features of adult corticotrophic cells. Both the αMSH content of the explants and αMSH release into the culture medium increased with time. Treatment with the dopamine agonist bromocriptine induced a strong dose-dependent decrease in αMSH secretion, which was significant after 3 days in culture, indicating that dopamine D2 receptors are able to regulate hormonal release of melanotrophic cells at early stages. This system constitutes a suitable model for further studies of factors controlling cell differentiation and cellular interactions involved in histogenesis.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 33
    ISSN: 1432-0878
    Schlagwort(e): Cerebral ganglia ; Neurohormones ; Molluscan insulin-related peptide ; Immunocytochemistry ; Tannic acid ; Planorbarius corneus (Mollusca)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Two groups of cerebral dorsal cells of the pulmonate snail Planorbarius corneus stain positively with antisera raised against synthetic fragments of the B- and C-chain of the molluscan pro-insulin-related prohormone, proMIP-I, of another pulmonate snail, Lymnaea stagnalis. At the light-microscopic level the somata of the dorsal cells and their axons and neurohemal axon terminals in the periphery of the paired median lip nerves are immunoreactive with both antisera. Furthermore, the canopy cells in the lateral lobes of the cerebral ganglia are positive. In addition, MIPB-immunoreactive neurons are found in most other ganglia of the central nervous system. At the ultrastructural level, pale and dark secretory granules are found in somata and axon terminals of the dorsal cells. Dark granules are about 4 times as immunoreactive to both antisera as pale granules. Release of anti-MIPB- and anti-MIPC-immunopositive contents of the secretory granules by exocytosis is apparent in material treated according to the tannic acid method. It is concluded that the dorsal and canopy cells synthesize a molluscan insulin-related peptide that is packed in the cell body into secretory granules and that is subsequently transported to the neurohemal axon terminals and released into the hemolymph by exocytosis. Thus, MIP seems to act as a neurohormone on peripheral targets. On the basis of the analogy between the dorsal cells and the MIP-producing cells in L. stagnalis, it is proposed that the dorsal cells of P. corneus are involved in the control of body growth and associated processes.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 34
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 267 (1992), S. 483-492 
    ISSN: 1432-0878
    Schlagwort(e): Dental follicle ; Cell culture ; Fibroblasts ; Immunocytochemistry ; Ultrastructure ; Collagen ; Gel-electrophoresis ; Western blotting ; Rat (Sprague-Dawley)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Because the dental follicle is necessary for the eruption of teeth of limited eruption, it was the objective of this study to determine if the cells of the follicle could be cultured in vitro. To achieve this, dental follicles and associated enamel organs were dissected from the first and second mandibular molars of 6–7-day-old rats (secretory stage of amelogenesis), and then cultured in a medium that promotes fibroblast growth — the predominant cell type of the dental follicle. The cultured cells grew to confluency and were kept through 3 passages before experimentation. The cultured cells were fibroblastic in shape, elongate with processes, and transmission electron microscopy revealed that they contained an abundant rough endoplasmic reticulum, but did not form desmosomes. Immunofluorescent staining for anti-vimentin showed that all the cells stained and electron-microscopic immunogold labeling indicated that the antibody was associated with intermediate filaments. As revealed by SDS-polyacrylamide gel electrophoresis and Western blotting, the cultured cells synthesized and secreted the extracellular matrix molecules fibronectin and procollagens. Subsequent immunofluorescence staining of permeabilized and non-permeabilized cells confirmed the presence of fibronectin and type I collagen both intra- and extracellularly. Thus, based on all the above characteristics, the cultured cells appeared to be fibroblasts derived from the dental follicle, although a few of the fibroblasts may be derived from undifferentiated mesenchymal cells interposed between the alveolar bone and follicle. Experiments now can be conducted to determine how these cultured cells respond directly to growth factors that alter the rates of tooth eruption.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 35
    ISSN: 1432-0878
    Schlagwort(e): Actin-like protein ; Fibronectin-like protein ; Regeneration ; Cell migration ; Immunocytochemistry ; Dugesia lugubris (Tricladida)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Actin- and fibronectin-like proteins were characterized in the planarian, Dugesia lugubris s.l., by sodium dodecyl sulphate polyacrylamide gel electrophoresis and immunoblotting analysis using antisera to vertebrate actin and fibronectin. These antisera recognized protein bands of 42 kDa and 220 kDa, respectively. In addition, the immunohistochemical distribution of both actin- and fibronectin-like material was examined by using immuno-electron microscopy. Actin-like protein was localized in myofibrils in various differentiation stages, and in the peripheral cytoplasm and lamellipodia of cells that were migrating. The fibronectin-like component was associated with the extracellular matrix in the fibrillar structures and with the surface of the migrating cells. Our data suggest that similar cellular and molecular mechanisms are involved in cell-matrix interactions and in the morphogenesis of living organisms at different evolutionary levels.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 36
    ISSN: 1432-0878
    Schlagwort(e): Retina ; Dopaminergic neurons ; Synapses ; Inner plexiform layer ; Immunocytochemistry ; Electron microscopy ; Bufo marinus (Anura)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Tyrosine hydroxylase (TH) immunocytochemistry was utilized to quantify dopaminergic synapses in the inner plexiform layer of the retina of Bufo marinus. Since dopaminergic cells have bistratified dendritic arborisation in the inner plexiform layer, attention was given to the segregation of synapses between the scleral and the vitreal sublaminae. Light-microscopically, a more elaborate dendritic branching was observed in the scleral than in the vitreal sublamina. In contrast, about 55% of synapses occurred in the vitreal one fifth of the inner plexiform layer, 30% in the scleral fifth, and 15% in the intermediate laminae. Input sources and output targets showed only minor quantitative differences between sublaminae 1 and 5. TH-immunoreactive processes were found in presynaptic (62.8%) and postsynaptic (37.2%) positions. Synapses to the stained dendrites derived from bipolar (40.4%) and amacrine (59.6%) cells, whereas outputs from the TH-positive processes were directed to amacrine cells (56.8%) and to small and medium-sized dendrites (35.4%); at least some of these can be considered as ganglion cell dendrites. TH-positive profiles neither formed synapses with each other nor were presynaptic to bipolar cell terminals. Junctional appositions of the immunoreactive profiles were occasionally seen on non-stained amacrine and ganglion cell dendrites in the scleral sublamina of the inner plexiform layer and on optic axons in the optic fibre layer. Although dopaminergic cells are mainly involved in amacrine-amacrine interactions, inputs from bipolar terminals and outputs to ganglion cell dendrites were also substantial, suggestive of a role also in vertical information processing.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 37
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 268 (1992), S. 65-70 
    ISSN: 1432-0878
    Schlagwort(e): Stanniocalcin ; Corpuscles of Stannius ; Embryology ; Immunocytochemistry ; Pronephros ; Oncorhynchus keta (Teleostei)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary An immunocytochemical technique was used to follow the embryological origin and development of the corpuscles of Stannius (CS) in the chum salmon, Oncorhynchus keta. Stanniocalcin immunoreactive (ir-) cells can be observed as early as 13 days before hatching. The ir-CS cells appear in clusters of variable size in close association with nephric ducts. In addition, individual ir-cells also occur at this stage amoung epithelial cells of the nephric ducts. these individual cells may give rise to clusters which subsequently increase in size, the largest reaching 100 μm in diameter by the time of hatching. During this period, dispersed CS cells become evident and develop into secondary clusters in the vicinity of the primary clusters. These clusters appear to fuse to form larger clusters with a lobular structure. Transfer of the larvae (20 days after hatching) from fresh water to 50% seawater, accelerates the development of the CS tissue, suggesting an important role of the CS in seawater adaptation.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 38
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 268 (1992), S. 453-461 
    ISSN: 1432-0878
    Schlagwort(e): Neuropeptide Y ; Brain, vertebrate ; Hypothalamus ; Pituitary gland, pars intermedia ; Nervus terminalis ; Immunocytochemistry ; Scyliorhinus torazame (Elasmobranchii)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Using a specific antiserum raised against synthetic neuropeptide Y, we examined the localization of immunoreactivity in the brain and hypophysis of the cloudy dogfish, Scyliorhinus torazame, by the peroxidase-antiperoxidase method. Immunoreactive perikarya were demonstrated in the ganglion of the nervus terminalis, the dorsocaudal portions of the pallium dorsale, the basal telencephalon, and the nucleus lateralis tuberis and the nucleus lobi lateralis in the hypothalamus. Labeled perikarya were also found in the tegmentum mesencephali, the corpus cerebelli, and the medulla oblongata. Some of the immunoreactive neurons in the hypothalamus were of the CSF-contacting type. The bulk of the labeled fibers in the nervus terminalis ran toward the basal telencephalon, showing radial projections and ramifications. Large numbers of these fibers coursed into the nucleus septi caudoventralis and the nucleus interstitialis commissurae anterioris, where they became varicose and occasionally formed fine networks or invested immunonegative perikarya. In the diencephalon, immunoreactive fibers were observed throughout the hypothalamus, e.g., in the pars neurointermedia of the hypophysis, the subependymal layer of the lobus inferior hypothalami, and in the neuropil of the posterior (mammillary) recess organ. Labeled fibers were scattered throughout the rest of the brain stem and were also seen in the granular layer of the cerebellum. These results suggest that, in the dogfish brain, neuropeptide Y or a related substance is involved in a variety of physiological processes in the brain, including the neuroendocrine control of the hypophysis.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 39
    ISSN: 1432-0878
    Schlagwort(e): Olfactory epithelium ; Comparative study ; Histochemistry ; Immunocytochemistry ; Non-specific label ; Microsmatic fish ; Three-spined stickleback, Gasterosteus aculeatus (Teleostei) ; Nine-spined stickleback, Pungitius pungitius (Teleostei)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The olfactory epithelium of the three-spined stickleback (Gasterosteus aculeatus) and the nine-spined stickleback (Pungitius pungitius) has been studied with a conventional histochemical and a novel immunological staining technique. In both species, the sensory epithelium is arranged in folds separated by non-sensory epithelial tissue. In the nine-spined stickleback, intrinsic folds consisting of non-sensory cells are found in the apical part of the sensory epithelium where they divide the surface of the sensory epithelium into small islets. These non-sensory cells are non-ciliated, flattened and piled on top of each other; they contain numerous electron-translucent vesicles. The intrinsic folds are absent from the sensory epithelium of the three-spined stickleback. In both species, axons of receptor cells form a layer of fibers in the sensory epithelium immediately above the basal cells. In the three-spined stickleback, thick branches of the olfactory nerve are frequently found in this layer. These branches are only occasionally observed in the sensory epithelium of the nine-spined stickleback. Thus, the three-spined stickleback and the nine-spined stickleback show considerable differences in the organization of the sensory regions of the olfactory epithelium.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 40
    ISSN: 1432-0878
    Schlagwort(e): Pituitary adenylate cyclase-activating peptide (PACAP) ; Immunocytochemistry ; Pancreas, endocrine, exocrine ; Insulin secretion ; Glucagon secretion ; Mouse (NMRI) ; Rat (Sprague-Dawley)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuropeptide that occurs in several tissues, e.g., in the gut. We have studied PACAP-like immunoreactivity in the pancreas of rat and mouse, and the effects of PACAP-38 on basal and stimulated insulin and glucagon secretion in the mouse. Immunofluorescence staining demonstrated the presence of PACAP-like immunoreactivity in nerve fibers in both the rat and mouse pancreas. The nerve fibers were seen in the exocrine pancreas and surrounding the islets. Occasionally, the nerve fibers occurred within the islets. Most PACAP-positive nerve fibers innervated the intrapancreatic ganglia, although no nerve cell bodies contained PACAP-like immunoreactivity. In-vivo experiments in mice revealed that basal plasma glucagon levels were increased by PACAP-39 injected intravenously at dose levels exceeding 1.8 nmol/kg. Furthermore, PACAP-38 (7 nmol/kg) potentiated the plasma glucagon response to the cholinergic agonist carbachol (0.16 μmol/kg). This potentiation was reduced to simple addition by pretreatment with a combined α- and β-adrenergic blockade by phentolamine (35 μmol/kg) and propranolol (8.5 μmol/kg). Moreover, PACAP-38 inhibited a carbachol-induced increase in the level of plasma insulin in the absence but not in the presence of adrenergic blockade. PACAP-38 increased basal plasma insulin levels and increased basal plasma glucose levels 6 min and 10 min, respectively, after injection of the peptide. We conclude that PACAP-like immunoreactivity exists in nerve fibers innervating the mouse and rat pancreas, particularly the intrapancreatic ganglia, and that PACAP-38 augments both basal and carbachol-stimulated glucagon secretion in the mouse.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 41
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 269 (1992), S. 315-322 
    ISSN: 1432-0878
    Schlagwort(e): Calcitonin gene-related peptide ; Islet amyloid polypeptide ; Immunocytochemistry ; Pancreas endocrine, exocrine ; Rat (Sprague-Dawley) ; Mouse (NMRI)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary It was previously demonstrated that the two chemically related peptides calcitonin gene-related peptide (CGRP) and islet amyloid polypeptide (IAPP) both occur in the pancreas. We have now examined the cellular localization of CGRP and IAPP in the rat and the mouse pancreas. We found, in both the rat and the mouse pancreas, CGRP-immunoreactive nerve fibers throughout the parenchyma, including the islets, with particular association with blood vessels. CGRP-immunoreactive nerve fibers were regularly seen within the islets. In contrast, no IAPP-immunoreactive nerve fibers were demonstrated in this location. Furthermore, in rat islets, CGRP immunoreactivity was demonstrated in peripherally located cells, constituting a major subpopulation of the somatostatin cells. Such cells were lacking in the mouse islets. IAPP-like immunoreactivity was demonstrated in rat and mouse islet insulin cells, and, in the rat, also in a few non-insulin cells in the islet periphery. These cells seemed to be identical with somatostatin/CGRP-immunoreactive elements. In summary, the study shows (1) that CGRP, but not IAPP, is a pancreati neuropeptide both in the mouse and the rat; (2) that a subpopulation of rat somatostatin cells contain CGRP; (3) that mouse islet endocrine cells do not contain CGRP; (4) that insulin cells in both the rat and the mouse contain IAPP; and (5) that in the rat, a non-insulin cell population apparently composed of somatostatin cells stores immunoreactive IAPP. We conclude that CGRP is a pancreatic neuropeptide and IAPP is an islet endocrine peptide in both the rat and the mouse, whereas CGRP is an islet endocrine peptide in the rat.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 42
    ISSN: 1432-0878
    Schlagwort(e): Growth hormone ; Prolactin ; Gonadotropin ; Adrenocorticotropin ; Immunocytochemistry ; Pituitary gland ; Sparus auratus (Teleostei)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The chronological appearance of endocrine cells in the pituitary of sea-bream (Sparus auratus) larvae was studied using antisera against salmon prolactin, trout growth hormone, salmon gonadotropin and N-terminal human adrenocorticotropin. The larval pituitary (1–12 days after hatching) was oval in shape and was composed of a dense mass of cells with few neurohypophysial fibres. By 60 days after hatching it began to resemble the adult and was divisible into a distinct rostral pars distalis containing prolactin and adrenocorticotropin cells; a proximal pars distalis containing somatotrophs and gonadotrophs and a pars intermedia. Cells immunoreactive with antisera against growth hormone were observed immediately after hatching (2 days post-fertilization). Weakly staining prolactin cells were observed 2 days later in the region corresponding to the rostral pars distalis. Cells immunoreactive with anti-gonadotropin and anti-adrenocorticotropin sera were observed in the pituitary 6 and 8 days after hatching, respectively. All the cell-types studied were immunoreactive from the time they were first identified until the final samples 90 days after hatching.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 43
    ISSN: 1432-0878
    Schlagwort(e): Dental pulp ; Laminin ; Collagen IV ; Odontoblast ; Nerve regeneration ; Immunocytochemistry ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The distribution of laminin-like immunoreactivity in adult normal and denervated cat mandibular tooth pulps was studied by the use of fluorescence microscopy and pre-embedding immunogold electron microscopy. Immunoreactivity to collagen IV was also assessed in order to distinguish basement membranes. In normal pulps, light-microscope laminin-like immunoreactivity was strong along blood vessels and Schwann cell sheaths, and a faint immunoreactivity was seen also in the odontoblast layer. Electron microscopy confirmed the laminin-like immunoreactivity of endothelial and Schwann cell basement membranes at all pulpal levels. In the odontoblast layer and the predentine, nerve-like structures lacking basement membranes but possessing strong membrane laminin-like immunoreactivity were encountered. In addition, a clear-cut laminin-like immunoreactivity of plasma membranes of the somata and processes of odontoblasts was seen. Observations on denervated pulps as well as pulps in which nerve regeneration had taken place did not reveal any changes in the pattern of laminin-immunoreactivity in basement membranes or odontoblasts. Distribution of collagen IV-like immunoreactivity was very similar to laminin-like immunoreactivity in basement membranes of blood vessels and Schwann cells, and appeared unaffected by denervation. The odontoblasts and nerve-like profiles in the odontoblast layer were devoid of collagen IV-like immunoreactivity. We propose that odontoblast-associated laminin could be of significance as guidance for regenerating terminal pulpal nerve fibers to appropriate targets.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 44
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 270 (1992), S. 47-56 
    ISSN: 1432-0878
    Schlagwort(e): Cilia ; Microvilli ; Secretory granules ; Mucus ; Freeze-substitution ; Immunocytochemistry ; Rana pipiens (Anura)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary This study showed that the olfactory mucus is a highly structured extracellular matrix. Several olfactory epithelial glycoconjugates in the frog Rana pipiens were localized ultrastructurally using rapid-freeze, freeze-substitution and post-embedding (Lowicryl K11M) immunocytochemistry. Two of these conjugates were obtained from membrane preparations of olfactory cilia, the glycoproteins gp95 and olfactomedin. The other conjugates have a carbohydrate group which in the olfactory bulb appears to be mostly on neural cell-adhesion molecules (N-CAMs); in the olfactory epithelium this carbohydrate is present on more molecules. Localization of the latter conjugates was determined with monoclonal antibodies 9-OE and 5-OE. Ultrastructurally all antigens localized in secretory granules of apical regions of frog olfactory supporting cells and in the mucus overlying the epithelial surface, where they all had different, but partly overlapping, distributions. Monoclonal antibody 18.1, to gp95, labeled the mucus throughout, whereas poly- and monoclonal anti-olfactomedin labeled a deep mucous layer surrounding dendritic endings, proximal parts of cilia, and supporting cell microvilli. Labeling was absent in the superficial mucous layer, which contained the distal parts of the olfactory cilia. Monoclonal antibody 9-OE labeled rather distinct areas of mucus. These areas sometimes surrounded dendritic endings and olfactory cilia. Monoclonal antibody 5-OE labeled membranes of dendritic endings and cilia, and their glycocalyces, and also dendritic membranes.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 45
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 270 (1992), S. 601-607 
    ISSN: 1432-0878
    Schlagwort(e): Dopamine ; HPLC ; Immunocytochemistry ; Hydra attenuata (Cnidaria)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary High performance liquid chromatography (HPLC), with electrochemical detection, is an analytical method sensitive enough to permit quantification of dopamine, dihydroxyphenylalanine (DOPA) and 5-S-cysteinyl DOPA in single or hemisected specimens ofHydra attenuata. Dopamine and 5-S-cysteinylDOPA appear to be the quantitatively predominant catechol compounds inH. attenuata, whereas DOPA is present in minor amounts. The presence of DOPA and 5-S-cysteinylDOPA, and the quantitative correlation between dopamine and these compounds in many specimens, suggests that dopamine inH. attenuata, as in higher animals, is formed through decarboxylation of DOPA. Contrary to the dopaminergic nerves in higher animals, DOPA inHydra seems to be oxidized and 5-S-cysteinyl DOPA is formed as a by-product. The oxidation of DOPA indicates that the hydroxylation of tyrosine into DOPA in the tissues ofH. attenuata is mediated by a tyrosinase rather than a tyrosine hydroxylase. Immunocytochemical methods demonstrate a highly variable distribution of dopamine in the tissues of different specimens ofH. attenuata. Dopamine immunoreactivity is confined to ectodermal tissue and can be found in several different cell types including nerve cells, battery cells, nematocytes, epithelial cells and interstitial undifferentiated cells. The large amounts of dopamine found in some specimens ofH. attenuata indicate some biological function, although its sporadic occurrence in neurites makes it less plausible as a generally utilized neurotransmitter in this animal.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 46
    ISSN: 1432-0878
    Schlagwort(e): Gastrin ; Gastrin-releasing peptide ; Neurotensin ; Vasoactive intestinal peptide ; Immunocytochemistry ; Harderian gland ; Rana esculenta (Anura)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The presence and distribution of gastrin-, gastrin-releasing peptide-, neurotensin-and vasoactive intestinal polypeptide-like immunoreactivity in the Harderian gland ofRana esculenta were studied at different times of the annual cycle. Gastrin-releasing peptide, neurotensin and vasoactive intestinal polypeptide-like substances were found either in the glandular cells, or in the nerve fibers surrounding the glandular acini. Gastrin-like immunoreactivity was confined to the glandular cells. The immunoreactivity varied during the annual cycle, with the greatest concentration being noted during the recovery phase of glandular secretory activity.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 47
    ISSN: 1432-0878
    Schlagwort(e): Immunocytochemistry ; Serotonin ; RFamide ; Development ; Paraspadella gotoi (Chaetognatha)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The distribution and development of serotonin-and RFamide-like immunoreactivities in the nervous system of Chaetognatha, Paraspadella gotoi, were examined in whole-mount preparations. In adults, a single serotonin-like immunoreactive (5HTLI) neuron and numerous RFamide-like immunoreactive (RFaLI) neurons were found in the central nervous system. Based on the structure of the fins, hooks, and eyes, seven postembryonic developmental stages were recognized. The most obvious features of the stages are: stage 1, newly hatched young; stage 2, elongation of a continuous lateral tail fin; stage 3, separation of the lateral and tail fins; stage 4, appearance of hooks; stage 5, pigmentation of eyes, stage 6, attachment by tail adhesive fins; stage 7, prey capture. Stage 1 did not show any immunoreactivity. The 5HTLI neuron first appeared at stage 4 and its axonal pathway became similar to the adult at stage 6. On the other hand, the RFaLI neurons appeared at stage 3 in the ventral ganglion. Some of their somata disappeared at stage 5 and the neuronal architecture resembled the adult at stage 7 although the RFaLI neurons in the cerebral ganglion were complete at the juvenile stage.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 48
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 267 (1992), S. 209-214 
    ISSN: 1432-0878
    Schlagwort(e): Testis ; Sulfhydryl oxidase ; Hypospermatogenesis ; Sertoli cell integrity ; Immunocytochemistry ; Man
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Sulfhydryl oxidase (SOx) immunoreactivity was investigated in the seminiferous epithelium of human biopsy material from the testes of 33 adult men with disturbed fertility. SOx immunoreactivity was expressed in normal seminiferous epithelium in type-A spermatogonia (27±4% of all spermatogonia) (n=4), in spermatocytes and round spermatids. Mature spermatozoa as well as Sertoli cells were unlabelled. within the interstitium, Leydig cells were immunopositive. In biopsies of oligozoospermic men showing hypospermatogenesis (n=24), an increase in labelled spermatogonia up to more than 90% was observed in biopsies, where seminiferous epithelia revealed only spermatogonia and Sertoli cells. Within the group of oligozoospermic patients there was a significant increase of labelled spermatogonia from 43±13% (〉20 mill/ejaculate) (n=7) to 55±16% ( 20 and 〉20 mill/ejaculate) (n=6) to 68±8% (〈5 mill/ejaculate) (n=11) and a significant (P=0.01) decrease of score count from 7.0±2.7 to 2.0±1.8. In this group the increase of labelled spermatogonia was correlated with sperm concentrations in the ajaculate (correlation coefficient: r=-0.6). In biopsies of azoospermic patients showing maturation arrest at the level of spermatocytes or spermatids (n=5) the percentage of labelled spermatogonia was within the range of 24% to 59%. Immunoreactivity in Sertoli cells was only found in single degenerating cells and in tubules showing Sertoli Cell Only Syndrome (SCO) without lumen formation. Sertoli cells within immature seminiferous cords were immunonegative, indicating that Sertoli cell SOx immunoreactivity is rather a sign of physiological alterations in degenerating cells than dependent on the stage of differentiation. Leydig cells did not show changes of immunoreactivity in any biopsy. It is concluded that SOx expression in spermatogonia may serve as a marker for spermatogenic efficiency.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 49
    ISSN: 1432-0878
    Schlagwort(e): α-Subunit ; Pituitary glycoprotein hormone ; PRL cell ; Pars distalis ; Colocalization ; Immunocytochemistry ; Bullfrog, Rana catesbeiana (Anura)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Our recent finding that the number of immunoreactive α-subunit cells was invariably greater than the total number of immunoreactive gonadotropin (GTH) and thyrotropin (TSH) cells in the bullfrog (Rana catesbeiana) pituitary gland raises the possibility that the α-subunit also exists in pituitary cells other than GTH and TSH cells. The present study demonstrates that there are a considerable number of immunoreactive prolactin (PRL) cells that are also stained with antibody against the α-subunit when adjacent sections are immunocytochemically examined. Neither immunoreactive growth hormone nor adrenocorticotropin cells are stained with the antibody against the α-subunit. The specificity of the antibody against the α-subunit and of that against PRL was demonstrated by preabsorption test, non-competitive binding test, and immunoblot analysis. Double-immunolabeling with gold particles of different sizes for the α-subunit and PRL revealed that most of the immunolabeled PRL-secretory granules are also labeled with the α-subunit antibody. The gold particles indicating the presence of the α-subunit were mostly found in the peripheral zone of the secretory granules.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 50
    ISSN: 1432-0878
    Schlagwort(e): Nervous system, central ; VD1/RPD2 system ; Neuropeptide immunocytochemistry ; Hybridization, in situ ; Immunocytochemistry ; Lymnaea stagnalis (Mollusca)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary VD1 and RPD2 are two giant neuropeptidergic neurons in the central nervous system (CNS) of the pond snail Lymnaea stagnalis. We wished to determine whether other central neurons in the CNS of L. stagnalis express the VD1/RPD2 gene. To this end, in situ hybridization with the cDNA probe of the VD1/RPD2 gene and immunocytochemistry with antisera specific to VD1 and RPD2 (the α1-antiserum, Mab4H5 and ALMA 6) and to R15 (the α1 and 16-mer antisera) were performed on alternate tissue sections. A VD1/RPD2 neuronal system comprising three classes of neurons (A1–A3) was found. All neurons of the system express the gene. Division into classes is based on immunocytochemical characteristics. Class A1 neurons (VD1 and RPD2) immunoreact with the α1-antiserum, Mab4H5 and ALMA 6. Class A2 neurons (1–5 small and 1–5 medium sized neurons in the visceral and right parietal ganglion, and two clusters of small neurons and 5 medium-sized neurons in the cerebral ganglia) immunoreact with the α1-antiserum and Mab4H5, but not with ALMA 6. Class A3 neurons (3–4 medium-sized neurons and a cluster of 4–5 small neurons located in the pedal ganglion) immunoreact with the α1-antiserum only. All neurons of the system are immunonegative to the R15 antisera. The observations suggest that the neurons of the VD1/RPD2 system produce different sets of neuropeptides. A group of approximately 15 neurons (class B), scattered in the ganglia, immunostained with one or more of the antisera, but did not react with the cDNA probe in in situ hybridization.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 51
    ISSN: 1432-0878
    Schlagwort(e): Nervous system, central ; Ganglia, invertebrate ; Octopamine ; Immunocytochemistry ; DUM neurone ; Neurosecretion ; Gryllus bimaculatus (Insecta)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The distribution of octopamine-immunoreactive neurons is described using whole-mount preparations of all central ganglia of the cricket, Gryllus bimaculatus. Up to 160 octopamine-immunoreactive somata were mapped per animal. Medial unpaired octopamine-immunoreactive neurons occur in all but the cerebral ganglia and show segment-specific differences in number. The position and form of these cells are in accordance with well-known, segmentally-organized clusters of large dorsal and ventral unpaired medial neurons demonstrated by other techniques. In addition, bilaterally arranged groups of immunoreactive somata have been labelled in the cerebral, suboesophageal and terminal ganglia. A detailed histological description of octopamine-immunoreactive elements in the prothoracic ganglion is given. Octopamine-immunoreactive somata and axons correspond to the different dorsal unpaired medial cell types identified by intracellular single-cell staining. In the prothoracic ganglion, all efferent neurons whose primary neurites are found in the fibre bundle of dorsal unpaired cells are immunoreactive. Intersegmental octopamine-immunoreactive neurons are also present. Collaterals originating from dorsal intersegmental fibres terminate in different neuropils and fibre tracts. Fine varicose fibres have been located in several fibre tracts, motor and sensory neuropils. Peripheral varicose octopamine-immunoreactive fibres found on several nerves are discussed in terms of possible neurohemal releasing sites for octopamine.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 52
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 269 (1992), S. 347-351 
    ISSN: 1432-0878
    Schlagwort(e): Immunocytochemistry ; Enkephalin ; Skin ; Touch dome ; Merkel cells ; Dense-core granules ; Mammalian species
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Immunogold staining failed to show met-enkephalin immunoreactivity in the Merkel cell dense-core granules of rats when examined by electron microscopy, but showed gold particle staining in the Merkel cell dense-core granules of mice and nude mice. Merkel cells of hamster, guinea pig, rabbit, cat and dog were also examined using a similar method, and different antisera dilutions. Immunogold particles were consistently found in the dense-core granules of mice and nude mice at all antisera dilutions, but not in the other species, except in the dog, where a very low labelling response was encountered. Merkel cells from skin touch domes or sinus hair follicles, did not exhibit any difference in peptide expression as far as met-enkephalin immunoreactivity was concerned. In addition, all species studied, including mice and nude mice, did not show leu-enkephalin immunoreactivity in their Merkel cell dense-core granules. It is concluded that species variability in peptide expression occurs in the Merkel cell dense-core granules, and may be closely related to the different methodologies used.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 53
    ISSN: 1432-0878
    Schlagwort(e): Pheromone-biosynthesis-activating neuropeptide ; Immunocytochemistry ; Helicoverpa zea (Insecta)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Production of sex pheromone in several species of moths has been shown to be under the control of a neuropeptide termed pheromone-biosynthesis-activating neuropeptide (PBAN). We have produced an antiserum to PBAN from Helicoverpa zea (Lepidoptera: Noctuidae) and used it to investigate the distribution of immunoreactive peptide in the brain-suboesophageal ganglion complex and its associated neurohemal structures, and the segmental ganglia of the ventral nerve cord. Immunocytochemical methods reveal three clusters of cells along the ventral midline in the suboesophageal ganglion (SOG), one cluster each in the presumptive mandibular (4 cells), maxillary (12–14 cells), and labial neuromeres (4 cells). The proximal neurites of these cells are similar in their dorsal and lateral patterns of projection, indicating a serial homology among the three clusters. Members of the mandibular and maxillary clusters have axons projecting into the maxillary nerve, while two additional pairs of axons from the maxillary cluster project into the ventral nerve cord. Members of the labial cluster project to the retrocerebral complex (corpora cardiaca and cephalic aorta) via the nervus corpus cardiaci III (NCC III). The axons projecting into the ventral nerve cord appear to arborize principally in the dorsolateral region of each segmental ganglion; the terminal abdominal ganglion is distinct in containing an additional ventromedial arborization in the posterior third of the ganglion. Quantification of the extractable immunoreactive peptide in the retrocerebral complex by ELISA indicates that PBAN is gradually depleted during the scotophase, then restored to maximal levels in the photophase. Taken together, our findings provide anatomical evidence for both neurohormonal release of PBAN as well as axonal transport via the ventral nerve cord to release sites within the segmental ganglia.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 54
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 268 (1992), S. 505-511 
    ISSN: 1432-0878
    Schlagwort(e): Dermis ; Collagen fibers ; Extracellular matrix ; Fibronectin ; Immunocytochemistry ; Man
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The distribution of collagen types I, III, IV, and of fibronectin has been studied in the human dermis by light and electron-microscopic immunocytochemistry, using affinity purified primary antibodies and tetramethylrhodamine isothiocyanate-conjugated secondary antibodies. Type I collagen was present in all collagen fibers of both papillary and reticular dermis, but collagen fibrils, which could be resolved as discrete entities, were labeled with different intensity. Type III collagen codistributed with type I in the collagen fibers, besides being concentrated around blood vessels and skin appendages. Coexistence of type I and type III collagens in the collagen fibrils of the whole dermis was confirmed by ultrastructural double-labelling experiments using colloidal immunogold as a probe. Type IV collagen was detected in all basement membranes. Fibronectin was distributed in patches among collagen fibers and was associated with all basement membranes, while a weaker positive reaction was observed in collagen fibers. Ageing caused the thinning of collagen fibers, chiefly in the recticular dermis. The labeling pattern of both type I and III collagens did not change in skin samples from patients of up to 79 years of age, but immunoreactivity for type III collagen increased in comparison to younger skins. A loss of fibronectin, likely related to the decreased morphogenetic activity of tissues, was observed with age.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 55
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 270 (1992), S. 113-124 
    ISSN: 1432-0878
    Schlagwort(e): Dopamine ; Nervous sytem, insect ; Ganglia, invertebrate ; Immunocytochemistry ; Schistocerca gregaria (Insecta)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The distribution of dopamine-like immunoreactivity in somata and neurites within the thoracic and abdominal nervous system of the locust Schistocerca gregaria was mapped using two polyclonal antibodies. The prothoracic ganglion contains three bilateral pairs of immunoreactive somata. Two of these lie close to the root of the anterior connective while the third lies between the somata of anterior and common inhibitory motor neurones. The primary neurites of the third pair have a distinctive branching pattern that can be followed through the neuropile and gives rise to a large descending axon. The mesothoracic ganglion has a single pair of antero-lateral immunoreactive somata but the metathoracic and fourth abdominal ganglia have none. The fifth, sixth, and seventh abdominal ganglia each have one pair of somata which are situated at the root of the sternal nerve while the terminal ganglion has a similar pair in the eighth neuromere only. Seven to ten immunoreactive axons enter each ganglion from each of the connectives. Some of these can be traced along the longitudinal tracts that traverse the neuropile. In each ganglion there is one axon in the median dorsal tract and two in ventral median tract. In the meso- and metathoracic ganglia an additional large axon is seen in lateral dorsal tract and dorsal intermediate tract. The axons in median dorsal, and dorsal intermediate tracts send out long ventro-lateral and ventro-medial branches which extend throughout much of the neuropile. Those in median ventral tract send markedly varicose branches to the ventral and dorsal edges of the medial neuropile.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 56
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 270 (1992), S. 339-352 
    ISSN: 1432-0878
    Schlagwort(e): Endocrine pancreas ; Ontogeny ; Regulatory peptides ; Immunocytochemistry ; Dicentrarchus labrax (Teleostei)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The development of the endocrine pancreas of the teleost sea bass (Dicentrarchus labrax, L.) was examined from hatching to 61 days, using the peroxidase-antiperoxidase technique for light microscopy. Mammalian and bonito insulin (mI and bI)-, salmo somatostatin-25 (SST-25)-, somatostatin-14 (SST-14a and b)-, glucagon-, bovine pancreatic polypeptide (PP)-, peptide tyrosine-tyrosine (PYY)- and salmo neuropeptide Y (NPY)-like immunoreactivity was demonstrated. Four ontogenetic stages were established according to the organization and immunostaining of the endocrine cells. One cell strand or primordial cord showing mI/bI- and SST-25/SST-14a-like immunoreactivity was first found at hatching in the dorsal epithelium of the anterior zone of the midgut (stage 1). One primitive islet, comprising outer SST-25/SST-14a- and inner mI/bI- and SST-14a/ SST-14b-immunoreactive cells, was found in 2- to 5-day-old larvae (stage 2). One single islet, in which glucagon-immunoreactive cells appear in the periphery, was found in larvae from 9 to 20 days after hatching (stage 3). One big islet containing, in addition, PP-immunoreactive cells in the outer region and slender cell processes which showed PYY-like immunoreactivity, was found from 25 to 61 days after hatching. During this period, primordial islets, composed of SST-25- and bI-immunoreactive cells, and clustered or isolated pancreatic endocrine cells, close to the pancreatic duct, as well as small and intermediate islets (secondary islets), in which glucagon, PP, PYY and NPY seem to be co-localized, were progressively found (stage 4). The origin of the endocrine pancreas of sea bass, and the ontogenetic and phylogenetic significance, are discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 57
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 270 (1992), S. 383-393 
    ISSN: 1432-0878
    Schlagwort(e): Gonadotropin-releasing hormone ; Immunocytochemistry ; Annual cycle-Mink ; Mustela vison
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The distribution of gonadotropin-releasing hormone-immunoreactive neurons and processes was mapped in the female mink brain using coronal, horizontal and sagittal sections. Perikarya were found along a ventral continuum including the olfactory tubercle, the diagonal band of Broca, the lateral septum, the preoptic and anterior hypothalamic area and the mediobasal hypothalamus; 80% of the perikarya were counted in the mediobasal hypothalamus. Fibres were mainly observed in the organum vasculosum of the lamina terminalis and the median eminence. A few processes terminated in the ependymal cells lining the third and lateral ventricles. The total number of immunoreactive perikarya was the highest in the brains of females sacrificed in July; it then significantly decreased until December. This variation is discussed in relation to the annual breeding cycle.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 58
    ISSN: 1432-0878
    Schlagwort(e): Ameloblasts ; Differentiation ; Proliferation ; Bromodeoxyuridine ; Enamel matrix proteins ; Immunocytochemistry ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary A double-staining immunocytochemical technique was used for the simultaneous detection, at the light- and electron-microscopical level, of proliferating bromodeoxyuridine (BrdU)-labelled cells and enamel protein (EP)-producing cells in the inner enamel epithelium (IEE) of rat tooth germ. BrdU-positive cells were found in the region of the IEE close to the cervical loop and never displayed EP-like immunoreactivity. BrdU-immunoreactivity was confined to the nucleus of replicating cells. In contrast, epithelial cells displaying EP-like immunoreactivity were found in the region of the forming dental cusp and were consistently BrdU-negative. EP-like immunoreactivity was detectable in the cytoplasmic compartments involved in the exocrine secretion pathway and in the extra-cellular matrix close to EP-immunoreactive cells. These data support the view that withdrawal from the cell cycle in the IEE is a temporal prerequisite for acquiring the functional competence of secreting EP. Moreover, cycling cells and secretory cells in the IEE constitute two separate compartments that are spatially defined, and that exhibit clear-cut staining patterns with respect to BrdU- and EP-immunoreactivity, respectively. We thus propose that BrdU-incorporation and EP-production may be used as specific markers of the differentiation of the IIE cells in studies of the possible role of growth factors, their receptors and oncoproteins in this tissue.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 59
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 270 (1992), S. 435-442 
    ISSN: 1432-0878
    Schlagwort(e): Neuropeptides ; Neuropeptide Y ; FMRFamide ; Immunocytochemistry ; Telencephalon ; Thalamus ; Salmo salar (Teleostei)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The colocalization of the peptides neuropeptide Y (NPY) and Phe-Met-Arg-Phe-NH2 (FMRFamide) in the brain of the Atlantic salmon was investigated with double immunofluorescence labeling and peroxidase-antiperoxidase immunocytochemical techniques. Colocalization of NPY-like and FMRE amide-like immunoreactivities was observed in neuronal cell bodies and fibers in four brain regions: in the lateral and commissural nuclei of the area ventralis telencephali, in the nucleus ventromedialis thalami, in the laminar nucleus of the mesencephalic tegmentum, and in a group of small neurons situated among the large catecholaminergic neurons in the isthmal region of the brainstem. All cell bodies in these nuclei were immunoreactive to both NPY and FMRF. We consistently observed larger numbers of FMRF-immunoreactive than NPY-immunoreactive fibers. In the nucleus ventromedialis thalami NPY- and FMRFamide-like immunoreactivities were colocalized in cerebrospinal fluid (CSF)-contacting neurons. NPY-immunoreactive, but not FMRF-immunoreactive, neurons were found in the stratum periventriculare of the optic tectum, and at the ventral border of the nucleus habenularis (adjacent to the nucleus dorsolateralis thalami). Neurons belonging to the nucleus of the nervus terminalis were FMRF-immunoreactive but not NPY-immunoreactive. The differential labeling indicates, as do our cross-absorption experiments, that the NPY and FMRFamide antisera recognize different epitopes. Thus, it is probable that NPY-like and FMRFamide-like substances occur in the same neurons in some brain regions.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 60
    ISSN: 1432-0878
    Schlagwort(e): Ganglia, invertebrate ; Neurosecretory cells ; DUM neurone ; Neurohemal organs ; Heart ; Immunocytochemistry ; Locusta migratoria (Insecta)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Three antisera were used to study the distribution and anatomy of bovine pancreatic polypeptide (BPP)-like/FMRFamide-like immunoreactive neurones within the unfused abdominal ganglia of the migratory locust, Locusta migratoria. All the antisera used stained two or more clusters of perikarya, localized anteriorly and posteriorly near the midline within each unfused abdominal ganglion. Double labelling experiments with intracellular dye injection, or differential backfilling, combined with subsequent immunostaining were carried out to identify these neurones. Two of the antisera (antisera 1 and 2, both raised against FMRFamide) stained three groups of midline neurones, located anterior dorsal, anterior ventral and posterior dorsal within the ganglion. Neurones of the former of these two clusters projected via the anterior median nerve to a neurohaemal organ. The posterior cluster of midline cells comprised immunopositive perikarya all but one of which also projected via the anterior median nerve to innervate the neurohaemal organ. Double labelling with Lucifer yellow and antisera 1 and 2 showed that the remaining neurone was the previously identified doral unpaired median (DUM)heart1 neurone. The third antiserum (AK141), also raised against FMRFamide, stained neurones within an anterior dorsal cluster, and in a posterior cluster. Double labelling with differential Co2+/Ni2+-backfilling and the antiserum 3 (AK141) demonstrated that the large neurones of both clusters belonged to the population of bilaterally projecting neurones (BPNs), including the DUMheart1 neurone. Since the antisera cross-react with BPP and fail to label neurones when preadsorped with BPP or FMRFamide, we conclude that the labelled neurones contain polypeptides of the FMRFamide/BPP-family.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 61
    ISSN: 1432-0878
    Schlagwort(e): Corpuscles of Stannius ; Stanniocalcin ; Immunocytochemistry ; Western blot ; Amia calva (Holostei)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary We used an antiserum against salmon stanniocalcin in an immunohistochemical, immunocytochemical, and Western blot analysis of bowfin (Amia calva) corpuscles of stannius. The bowfin is one of two extant holostean species with ancient ancestral links to modern-day bony fishes. The corpuscles of Stannius (white corpuscles) of the bowfin were scattered throughout much of the kidney among the adrenocortical homolog (yellow corpuscles) but could be distinguished from the adrenocortical homolog by their positive staining with both the periodic acid-Schiff reaction and a salmon stanniocalcin antiserum. Immunoreactivity was confined to cytoplamic granules and was absent when the antiserum was blocked with salmon stanniocalcin or with a crude extract of bowfin corpuscles of Stannius. When bowfin corpuscle-of-Stannius extracts were subjected to sodium dodecyl sulphate electrophoresis and Western blot analysis, two closely spaced bands were evident (43–45 kDa). Staining of both bands was abolished by pre-absorption of the antiserum with salmon stanniocalcin. In comparison to salmon stanniocalcin, the reputed bowfin hormone migrated faster in gels, suggesting a smaller apparent size. The purification of bowfin stanniocalcin should yield important new information regarding the evolution of this unique calcium-regulating hormone.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 62
    ISSN: 1432-0878
    Schlagwort(e): Histamine ; Biochemistry ; Immunocytochemistry ; Retina ; Photoreceptors ; Paraboloid ; Turtle, Pseudemys scripta (Chelonia)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary A combination of immunocytochemical and biochemical methods was used to study histamine in the turtle retina. Histamine-like immunoreactivity was localized within paraboloids of certain cone photoreceptors by use of two different antisera directed against histamine. Preincubation of eyecups in Ringer's containing 10 μM histamine selectively increased the immunoreactivity of these photoreceptor paraboloids. The present localization of histamine in paraboloids indicated that, although histamine is in photoreceptors of the turtle retina, it may play some metabolic or neuromodulatory role, and not function as a neurotransmitter.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 63
    ISSN: 1432-0878
    Schlagwort(e): Alcohol dehydrogenase (ADH) ; Oogenesis ; Vitellogenesis ; Yolk ; Immunocytochemistry ; Drosophila melanogaster (Insecta)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The use of monoclonal antibodies against Drosophila alcohol dehydrogenase (ADH) provides a powerful tool in the analysis of the tissue and temporal patterns of Adh gene expression. Immunocytochemical techniques at the light- and electron-microscopic levels have been used to determine the distribution of ADH in the ovarian follicles of D. melanogaster during oogenesis. In the early stages of oogenesis, small amounts of ADH are detectable in the cystocytes. At the beginning of vitellogenesis (S7), ADH appears to be located mainly in the nurse cells. From stage S9 onwards, the ADH protein is evenly distributed in the ooplasm until the later stages of oogenesis (S13–14), when multiple ADH-positive bodies of varying size appear in the ooplasm. This change in distribution is a result of the compartmentalization of the ADH protein within the glycogen yolk or β-spheres. Yolk becomes enclosed within the lumen of the primitive gut during embryonic development, and thus our results suggest a mechanism for the transfer of maternally-inherited enzymes to the gut lumen via yolk spheres.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 64
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 268 (1992), S. 277-281 
    ISSN: 1432-0878
    Schlagwort(e): Lung ; Elastin-binding protein ; Lectins ; Galactose ; Monocytes ; Immunocytochemistry ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary 67 kDa elastin-binding protein (RL-67EBP) has been isolated from neonatal rat lungs by the use of an elastin-coupled affinity column, followed by elution with either lactose or synthetic elastin hexapeptide (VGVAPG), and immunohistochemistry has been used on perinatal rat lungs to determine the tissue localization of this protein. No immunoreactive structures occur in fetal lungs, or in the lungs of day-1 and-4 neonates. On day-7 after birth, immunoreactive cells appear in the subepithelial connective tissue of the intrapulmonary airways, from day-10 on, these cells become evenly distributed in the alveolar parenchyma. Occasionally, some cells occur in the alveolar air space, being free from the surface of the alveolar septum. Unpermeabilized cells obtained by bronchoalveolar lavage, show cell surface immunoreactivity, indicating that RL-67EBP is expressed on the surface membrane of the cells. From these findings, it is suggested that the immunoreactive cells are blood-borne monocytes, and that RL-67EBP may function as an elastin peptide receptor by which monocytes mobilize through interstitial connective tissue during their migration from blood to alveolar air space, where they eventually differentiate into alveolar macrophages.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 65
    ISSN: 1432-0878
    Schlagwort(e): Neurosecretory cells ; Brain ; Immunocytochemistry ; Prothoracicotropic hormone ; Insulin-related peptide ; Neuroparsins ; Locusta migratoria (Insecta)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Using a monoclonal antibody directed against a synthetic pentadecapeptide corresponding to the N-terminus of the prothoracicotropic hormone (PTTH) of Bombyx mori, we report the presence of immunoreactive molecules in a large number of median neurosecretory cells of the pars intercerebralis of the migratory locust, Locusta migratoria. These cells correspond to the A1 cell type which we show to contain also neuroparsins, a family of predominant neurohormones of the migratory locust. In contrast, PTTH-like molecules are absent from A2 cells of the pars intercerebralis which contain Locusta insulin-related peptide (LIRP). Developmental studies show the presence of PTTH-related substances in neurosecretory cells of Locusta migratoria from late embryogenesis to adult development, including ageing vitellogenic female adults.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 66
    ISSN: 1432-0878
    Schlagwort(e): Sodium influx-stimulating (SIS) peptide ; Na+ transport ; In situ hybridization ; Immunocytochemistry ; Lymnaea stagnalis (Mollusca)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The functional morphology of the neuroendocrine system producing sodium influx-stimulating (SIS) peptide in the pond snail, Lymnaea stagnalis, was studied by in situ hybridization and immunocytochemistry. The SIS-peptide, which is 76 amino acids long, stimulates sodium uptake from the ambient medium. Two synthetic DNA probes were used for in situ hybridization. The nucleotide sequences were chosen from the cDNA structure; they encode amino acids 8–17 and 64–73, respectively. SIS-peptide sequences 10–20 and 67–76 were synthesized and antibodies were raised to them and affinity-purified. In addition to these antibodies, a monoclonal antibody raised to a bioactive, high-pressure liquid chromatography (HPLC)-purified brain extract was used for immunocytochemistry. Paraffin sections of central nervous systems and of whole snails were studied. The SIS-peptide system could be identified as the previously described yellow cell (YC) system by comparing alternate sections treated with the DNA probes, stained with the antibodies, or stained with alcian blue-alcian yellow. SIS-peptide neurons (∼45) occur in the ganglia of the visceral ring and in the proximal parts of visceral nerves. Axons run in the nerves of these and in several nerves of other ganglia. Numerous axon branches penetrate the perineurium forming a vast central neurohemal area. The SIS-peptide system innervates the pericardium, the nephridial gland, the reno-pericardial canal, the ureter, the spermoviduct and gonadal acini, the anterior aorta, the ventral buccal artery, and the penis protractor muscle. The morphology of the system is discussed in relation to the process of sodium ion uptake from the ambient medium and from pro-urine, and to that of regulating blood pressure. In the central nervous system and other organs, neurons and axons not labeled with the DNA probes, but immunoreactive to one or two of the antibodies, were observed. It seems unlikely that these elements are functionally related to the SIS-peptide system.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 67
    ISSN: 1432-0878
    Schlagwort(e): Pancreas, endocrine ; Immunocytochemistry ; Muscarinic acetylcholine receptor ; Acetylcholine ; Somatostatin ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Immunocytochemical application of the antimuscarinic acetylcholine receptor antibody M35 to pancreas tissue revealed the target areas for the parasympathetic nervous system. Immunoreactivity in the endocrine pancreas was much higher than that in the exocrine part. Moreover, the endocrine cells at the periphery of the islets of Langerhans displayed the highest level of immunoreactivity. Based on these findings in the mantle of the islets, two types of islets have been distinguished: type-I islets with intensely stained mantle cells, and type-II islets with a much lower concentration of these cells. On average, type-I islets were larger (244.8 μm±6.1 SEM) than type-II islets (121.5 μm±3.8 SEM). M35-immunoreactivity was present on the majority of D cells, which were characterized by their immunoreactivity to somatostatin [of 446 D cells 356 (79.8%) were M35-immunopositive]. However, only a small proportion of the intensely stained mantle cells belonged to the D cell population. Therefore, it is concluded that the majority of the intensely stained mantle cells represent glucagon-secreting A and/or pancreatic polypeptide-secreting F cells. The intensity of M35-immunoreactivity at the periphery and central core of the islets paralleled the density of cholinergic innervation, suggesting a positive correlation between the intensity of cholinergic transmission and the number of muscarinic acetylcholine receptors at the target structures. The present study further revealed some striking parallels for the muscarinic acetylcholine receptor characteristics between the (endocrine) pancreas and the central nervous system.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 68
    ISSN: 1432-0878
    Schlagwort(e): Molluscan insulin-related peptide ; Neuropeptide ; Light green cells ; Differential gene expression ; Immunocytochemistry ; In situ hybridization ; Lymnaea stagnalis (Mollusca)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary In the pond snail Lymnaea stagnalis, the growth regulating system consists of (1) about 200 neuroendocrine light green cells, located in four clusters in the cerebral ganglia, and (2) the paired canopy cells, located in the lateral lobes. These cells express genes encoding the molluscan insulin-related peptides (MIPs). Six MIP genes have previously been identified. Four of these (I, II, III and V) are expressed in the light green cells and the canopy cells. The MIP-VI gene is a pseudogene. In the present in situ hybridization study, using oligonucleotide probes specific to the transcripts of MIP-I,-II,-III,-IV, and-V, no signal was obtained with the MIP-IV probe, indicating that gene IV is also a pseudogene. With the other four probes, two types of light green cells were distinguished. Type-A cells express all four MIP genes, whereas type-B cells do not (or only faintly) express the MIP-I gene. Gene III is relatively strongly expressed in type-B cells. Genes II and V are moderately expressed in both cell types. Type-A cells are mainly located in the periphery of the clusters, whereas type-B cells are present in the center. The canopy cell resembles type-A light green cells. The expression levels of the MIP-II and MIP-V genes are low in the canopy cell. The expression pattern of the MIP genes correlates with the staining pattern of the anti-MIP-C antibody, which has been raised to a synthetic C-fragment shared by MIP-I,-II and-V. Type-A cells stain more intensely with the antibody than type-B cells.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 69
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 270 (1992), S. 15-23 
    ISSN: 1432-0878
    Schlagwort(e): Allatostatin ; Corpus allatum inhibitors ; Immunocytochemistry ; Brain ; Neuroendocrine complex ; Diploptera punctata (Insecta)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary A monoclonal antibody against allatostatin I was used to demonstrate the allatostatin-immunoreactive pathways between the brain and the corpus cardiacum-corpus allatum complex in the adult cockroach Diploptera punctata. The antibody was two to three orders of magnitude more sensitive to allatostatin I than to the other four known members of the allatostatin family. Whole and sectioned brains in which immunoreactivity was localized with horseradish peroxidase-H2O2-diaminobenzidine reaction showed strongly immunoreactive cells in the pars lateralis of the brain with axons leading to and arborizing in the corpus cardiacum and the corpus allatum. Although many neurosecretory cells of the pars intercerebralis project to the corpora allata only, four strongly immunoreactive cells were evident here (two pairs on either side), and these did not project to the corpus cardiacum and corpus allatum but rather terminated within the protocerebrum in areas in which lateral cells also formed arborizations. Immunoreactivity was found in many other cells in the brain, especially in the tritocerebrum.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 70
    Digitale Medien
    Digitale Medien
    Springer
    Protoplasma 168 (1992), S. 125-135 
    ISSN: 1615-6102
    Schlagwort(e): Morphogenesis ; Phagotrophic ; Euglenoids ; Immunocytochemistry ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The disruption and development of the siphon during division ofEntosiphon have been followed by immunofluoresence with both an anti-cement MAb (IIID12) and an anti-tubulin MAb. (IVA10), by nuclear DNA labelling and by electron microscopy of serial section. The disruption of the parental siphon begins at the reservoir level where two new transversely orientated daughter siphons arise. In the degenerating bundles the cement disappears, first liberating the microtubules which then depolymerize. The first structure which surrounds the anterior part of the two young siphons is a loop of 5 microtubules linked to the reservoir membrane. From around this loop a row of perpendicular microtubules sink in the cytosplasm; they will form the primary row of microtubules in the definitive bundles. Inside the loop, reinforced microtubules are seen beneath the membrane, they will generate the future vanes, and also penetrate into the cytosplasm. Amorphous material surrounds the young siphons and may correspond to cement material. The growth of the siphons proceeds as they adopt a central longitudinal position in the cell. The cement material progressively condenses on structures such as the primary row of microtubules. The bundles, the supplementary plaque, and the scaffold. After flagellar partition each of the canals becomes distinct and cytokinesis occurs from the anterior end. These observations indicate that the microtubular loop could be the source of microtubule-organizing centre (MTOC) proteins initiating the assembly of the primary row of microtubules. Bundle microtubules start to assemble at the anterior end and extend backwards. The microtubules of the loop could be linked to roots associated with the basal bodies which double in number before division. The cement later condenses, linking and stabilizing the structures. Microfibrils play an important role in basal body and siphon separation and positioning.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 71
    Digitale Medien
    Digitale Medien
    Springer
    Protoplasma 170 (1992), S. 166-176 
    ISSN: 1615-6102
    Schlagwort(e): Cryptophytes ; Chloroplasts ; Light-harvesting complexes ; Phycoerythrin ; Chlorophylla/c 2 ; Immunocytochemistry ; Freeze ; fracture labelling
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Immunocytochemical techniques using colloidal gold as the marker have been used to examine the location of the two light harvesting pigment-protein complexes in cryptophyte chloroplasts. A comparison of post-embedding thin section labelling and freeze fracture labelling has been carried out onRhodomonas salina using polyclonal antibodies to a chlorophylla/c 2 light-harvesting complex, phycoerythrin and the β-subunit of phycoerythrin. The effect of different fixation procedures on the intensity of labelling and ac curacy of antigen location have been examined and the effectiveness of uranyl acetate and tannic acid in improving both the preservation of thylakoid structure and labelling density of phycoerythrin has been demonstrated. Freeze fracture labelling gives better spatial res olution of the different antigens than post-embedding labelling, as well as better definition of thylakoid membranes. It confirms the location of phycoerythrin in the thylakoid lumen and the location of the chlorophylla/c 2 LHC in both appressed and unappressed thylakoid membranes.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 72
    Digitale Medien
    Digitale Medien
    Springer
    Protoplasma 171 (1992), S. 123-133 
    ISSN: 1615-6102
    Schlagwort(e): Endosperm ; Floury-2 ; Immunocytochemistry ; Protein bodies ; Zea mays
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The seed storage proteins of maize (Zea mays L.) are synthesized during endosperm development on membrane-bound polyribosomes. These proteins, collectively called zeins, are translocated into the lumen of the rough endoplasmic reticulum, where they assemble into protein bodies. Protein body formation in normal genotypes occurs via an ordered deposition of the various types of zeins, and leads to the formation of spherical structures with a diameter of about 1 μm. These structures consist of a central core that contains predominantly α-zein; this central region is surrounded by a peripheral layer of β- and γ-zeins, and the entire structure is bounded by rough endoplasmic reticulum. In the endosperm mutant floury-2 the levels of all classes of zeins are reduced; these kernels exhibit an opaque phenotype instead of the vitreous phenotype observed in normal genotypes. In contrast to the discrete, spherical protein bodies which are formed in normal maize endosperm, the protein bodies within floury-2 endosperm are irregular and the zeins are disorganized; patches of β- and γ-zeins occur within irregularly lobed clusters of α-zein within the lumen of the rough endoplasmic reticulum. The implications of this aberrant distribution are discussed, both with respect to protein body development and kernel characteristics.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 73
    ISSN: 1615-6102
    Schlagwort(e): Fucus ; Light-harvesting complex ; Photosystem I complex ; Thylakoids ; Immunocytochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The repartition of light-harvesting complex (LHC) and photosystem I (PS I) complex has been examined in isolated plastids ofFucus serratus by immunocytochemical labelling. LHC is distributed equally all along the length of thylakoid membranes, without any special repartition in the appressed membranes of the three associated thylakoids ofFucus. PS I is present on all the thylakoid membranes, but the external membranes of the three associated thylakoids are largely enriched relatively to the inner ones. This specific repartition of PSI on non-appressed membranes can be compared to the localization of PSI on stroma thylakoid membranes of higher plants and green algae. Consequently, although they share some common features with those of higher plants and green algae, the appressions of thylakoids in brown algae has neither the same structure nor the same functional role as typical grana stacked membranes in the repartition of the harvested energy.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 74
    ISSN: 1617-4623
    Schlagwort(e): Adenylate kinase family ; Yeast ; Mitochondria
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Making use of the polymerase chain reaction primed by oligonucleotides corresponding to regions conserved between members of the nucleoside monophosphate kinase family, we have isolated the yeast gene PAK3. Pak3p belongs to the subgroup of long-form adenylate kinase isozymes (deduced molecular mass 25.3 kDa) and exhibits highest sequence similarity to bovine AK3 rather than to the yeast isozyme, Aky2p. The gene is shown to be non-essential because haploid disruption mutants are viable, both in the presence and absence of a functional AKY2 allele. It maps on chromosome V upstream of RAD3. Its expression level is low when cells are grown on glucose or other fermentable carbon sources and about threefold higher on glycerol, but can be significantly induced by ethanol. A PAK3/mouse dihydrofolate reductase fusion construct expressed in yeast is targeted to mitochondria. Transformation with PAK3 on a multicopy plasmid complements neither adenylate kinase deficiency in an aky2-disrupted yeast strain nor in Escherichia coli cells conditionally defective in adenylate kinase.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 75
    ISSN: 1617-4623
    Schlagwort(e): Filamentous fungi ; Complementation ; Yeast ; Histidine biosynthetic genes ; Shuttle vector
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The Trichoderma harzianum imidazoleglycerolphosphate dehydratase gene (igh) has been isolated by complementation of a Saccharomyces cerevisiae his3 mutant using a direct expression vector. This Escherichia coli-yeast shuttle vector was developed to allow efficient cloning and expression of cDNA libraries. The cDNA is 627 nucleotides long and codes for a protein of 209 amino acids with an apparent molecular mass of 22 466 daltons. The predicted protein sequence showed 63.6%, 58.7%, and 38.4% identity respectively to the corresponding enzymes from S. cerevisiae, Pichia pastoris and E. coli. Northern analysis showed that the expression of the igh gene in T. harzianum is not inhibited by external histidine and the level of igh mRNA was about threefold higher in cells starved of histidine.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 76
    ISSN: 1617-4623
    Schlagwort(e): Peroxisomes ; Targeting signals ; Yeast ; Hansenula polymorpha
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Dihydroxyacetone synthase (DAS) and methanol oxidase (MOX) are the major enzyme constituents of the peroxisomal matrix in the methylotrophic yeast Hansenula polymorpha when grown on methanol as a sole carbon source. In order to characterize their topogenic signals the localization of truncated polypeptides and hybrid proteins was analysed in transformed yeast cells by subcellular fractionation and electron microscopy. The C-terminal part of DAS, when fused to the bacterial β-lactamase or mouse dihydrofolate reductase, directed these hybrid polypeptides to the peroxisome compartment. The targeting signal was further delimited to the extreme C-terminus, comprising the sequence N-K-L-COOH, similar to the recently identified and widely distributed peroxisomal targeting signal (PTS) S-K-L-COOH in firefly luciferase. By an identical approach, the extreme C-terminus of MOX, comprising the tripeptide A-R-F-COOH, was shown to be the PTS of this protein. Furthermore, on fusion of a C-terminal sequence from firefly luciferase including the PTS, β-lactamase was also imported into the peroxisomes of H. polymorpha. We conclude that, besides the conserved PTS (or described variants), other amino acid sequences with this function have evolved in nature.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 77
    Digitale Medien
    Digitale Medien
    Springer
    Molecular genetics and genomics 236 (1992), S. 145-154 
    ISSN: 1617-4623
    Schlagwort(e): Cell differentiation ; G protein ; Adaptation ; STE50 ; Yeast
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary A new gene, STE50, which plays an essential role in cell differentiation in Saccharomyces cerevisiae was detected and analysed. STE50 expression is not cell type-specific and its expression in MAT a and MATα cells is unaffected by pheromones. When present on a high copy number plasmid, STE50 causes supersensitivity to α-pheromone, and increases the level of α-pheromone-induced transcription of FUS1 in haploid a cells. Mutants bearing either of the two gene disruptions, ste50-1 or ste50-2, are sterile and have a modulated sensitivity to α-pheromone. The overexpression of STE4 (Gβ) in wild-type cells elicits a constitutive growth arrest signal, however this phenotype is suppressed by a C-terminal truncation mutation in STE50 (ste50-2). In contrast, the constitutive activation of the pheromone response pathway caused by disruption of GPA1 (Gα) is not suppressed in ste50-2 mutants. The ste50-2 mutation partially suppresses the desensitisation defect of the sst2-1 mutation, and the resulting ste50-2 sst2-1 mutants restore fertility. Our result sindicate that the ste50-2 mutant may have a defect in adaptation (hyperadaptation), and suggest a possible interaction of STE50-2 with the Gα subunit of the G protein.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 78
    Digitale Medien
    Digitale Medien
    Springer
    Molecular genetics and genomics 234 (1992), S. 233-243 
    ISSN: 1617-4623
    Schlagwort(e): Yeast ; Heme ; Sequence ; Regulation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Porphobilinogen deaminase is the third enzyme in the heme biosynthetic pathway. hem3 mutants in Saccharomyces cerevisiae are deficient in porphobilinogen deaminase activity. We have isolated the HEM3 gene by complementation of the heme auxotrophy of a hem3 mutant. Sequence analysis reveals an open reading frame of 981 nucleotides. The derived amino acid sequence of the protein encoded by HEM3 shows extensive homology to the reported sequences for porphobilinogen deaminase from a number of other sources, indicating that HEM3 is the structural gene for porphobilinogen deaminase. Earlier reports have suggested that expression of HEM3 is induced by porphobilinogen, the substrate of the encoded enzyme. We have investigated the transcription of HEM3 and have found that it is not affected by the ability of the cell to make porphobilinogen or heme. However, we have found that HAP2 and HAP3 gene products are involved in the expression of HEM3. An important element required for expression of HEM3 has been localized to a small region that contains a sequence homologous to the HAP2-3-4 binding sites of several genes including HEM1. These findings suggest that HEM3 expression is regulated in the same manner as that of HEM1 which encodes the first enzyme of the heme biosynthetic pathway.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 79
    Digitale Medien
    Digitale Medien
    Springer
    Molecular genetics and genomics 235 (1992), S. 97-103 
    ISSN: 1617-4623
    Schlagwort(e): Gene conversion ; Yeast ; Plasmid ; Recombination
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Nonreciprocal recombination (gene conversion) between homologous sequences at nonhomologous locations in the genome occurs readily in the yeast Saccharomyces cerevisiae. In order to test whether the rate of gene conversion is dependent on the number of homologous copies available in the cell to act as donors of information, the level of conversion of a defined allele was measured in strains carrying plasmids containing homologous sequences. The level of recombination was elevated in a strain carrying multiple copies of the plasmid, compared with the same strain carrying a single copy of the homologous sequences either on a plasmid or integrated in the genome. Thus, the level of conversion is proportional to the number of copies of donor sequences present in the cell. We discuss these results within the framework of currently favoured models of recombination.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 80
    ISSN: 1617-4623
    Schlagwort(e): Linker-insertion mutagenesis ; RNA polymerase II ; Conditional-lethal mutants ; Yeast
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Linker-insertion mutagenesis was used to isolate mutations in the Saccharomyces cerevisiae gene encoding the largest subunit of RNA polymerase II (RP021, also called RPBI). The mutant rpo21 alleles carried on a plamid were introduced into a haploid yeast strain that conditionally expresses RP021 from the inducible promoter pGAL10. Growth of this strain on medium containing glucose is sustained only if the plasmid-borne rpo21 allele encodes a functional protein. Of nineteen linker-insertion alleles tested, five (rpo21-4 to −8) were found that impose a temperature-sensitive (ts) lethal phenotype on yeast cells. Four of these five is alleles encode mutant proteins in which the site of insertion lies near one of the regions of the largest subunit that have been conserved during evolution. Two of the is mutants (rpo21-4 and rpo21-7) display pleiotropic phenotypes, including an auxotrophy for inositol and a decreased proliferation rate at the permissive temperature. The functional relationship between RP021 and RP026, the gene encoding the 17.9 kDa subunit shared by RNA polymerases 1, 11, and III was investigated by determining the ability of increased dosage of RP026 to suppress the is phenotype imposed by rpo21-4 to −8. Suppression of the is defect was specific for the rpo21-4 allele and was accompanied by co-suppression of the inositol auxotrophy. These results suggest that mutations in the largest subunit of RNA polymerase II can have profound effects on the expression of specific subsets of genes, such as those involved in the metabolism of inositol. In the rpo21-4 mutant, these pleiotropic phenotypes can be attributed to a defective interaction between the largest subunit and the RP026 subunit of RNA polymerase II.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 81
    Digitale Medien
    Digitale Medien
    Springer
    Molecular genetics and genomics 233 (1992), S. 327-330 
    ISSN: 1617-4623
    Schlagwort(e): GAM2 ; SIN3 ; Transcriptional regulator ; Glucoamylase ; Yeast
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary We have cloned GAM2, which is required for transcription ofSTA1, a gene encoding an extracellular glucoamylase inSaccharomyces cerevisiae var.diastaticus. DNA sequence analysis revealed thatGAM2 is the same gene asSIN3, known to be a general negative regulator of yeast genes. RNA blot analysis indicated thatGAM2/SIN3 also acts as a positive regulator ofGAM3/ADR6, which in turn is required for transcription ofSTA1 andADH2. These results suggest thatGAM2 regulatesSTA1 expression through transcriptional activation ofGAM3 and indicate that GAM2/SIN3 protein is a transcriptional regulator that can play a role in both activation and repression of transcription.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 82
    Digitale Medien
    Digitale Medien
    Springer
    Journal of bioenergetics and biomembranes 24 (1992), S. 309-317 
    ISSN: 1573-6881
    Schlagwort(e): Yeast ; proton ATPase ; sequence alignment ; hydrophobic regions
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie , Physik
    Notizen: Abstract Seventeen protein sequences of H+-ATPases from plants (Arabidopsis thaliana, Nicotiana plumbaginifolia, Lycopersicum esculentum), fungi (Sacharomyces cerevisiae, Schizosaccharomyces pombe, Zygosaccharomyces rouxii, Neuropora crassa, Candida albicans), and a parasitic ciliate (Leishmania donovani) have been aligned. Twenty sequence fragments were identified which were conserved in H+-, Na+/K+-, and Ca++ plasma membrane-ATPases. In addition, a total of 118 residues not located in these fragments were found to be conserved in all H+-ATPases. Among those, 38 amino acid residues were screened out as being priority targets for site-directed mutagenesis experiments aimed at the identification of the amino acid residues specifically involved in cation specificity.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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