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  • Zea mays  (43)
  • AERODYNAMICS
  • Analytical Chemistry and Spectroscopy
  • Animals
  • Life and Medical Sciences
  • Physics
  • Yeast
  • Springer  (73)
  • 1990-1994  (73)
  • 1975-1979
  • 1925-1929
  • 1992  (73)
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Verlag/Herausgeber
Erscheinungszeitraum
  • 1990-1994  (73)
  • 1975-1979
  • 1925-1929
Jahr
  • 1
    Digitale Medien
    Digitale Medien
    Changes in protein composition ofSaccharomyces brewing strains in response to heat shock and ethanol stress (1992)
    Springer
    Journal of industrial microbiology and biotechnology 9 (1992), S. 229-234 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF01569628
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  • 2
    Digitale Medien
    Digitale Medien
    Genetic analysis of ubiquitin-dependent protein degradation (1992)
    Springer
    Cellular and molecular life sciences 48 (1992), S. 172-178 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF01923510
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  • 3
    Digitale Medien
    Digitale Medien
    Sequential development of pathogens in the maize tarspot disease complex (1992)
    Springer
    Mycopathologia 117 (1992), S. 157-161 
    Details
    ISSN: 1573-0832
    Schlagwort(e): Phyllachora maydis ; Monographella maydis ; Coniothyrium phyllachorae ; Zea mays ; tarspot complex
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The tarspot complex is caused by the interaction of Phyllachora maydis and Monographella maydis. Coniothyrium phyllachorae, possibly a mycoparasite, is found in older ascostromata of P. maydis, which always appears first causing tarspot. M. maydis follows and is responsible for the damaging “fisheye” symptom. The fisheye symptom is always associated with a tarspot in the center of the lesion, whereas 12 to 20% of the Phyllachora ascostromata remained free of M. maydis. Inoculations of maize leaves with the Microdochium anamorph of the Monographella (usually produced in lesions) failed to produce infections. Some infections with M. maydis were, however, obtained under unusual conditions in the field. Inoculations onto tarspots in the laboratory were unsuccessful, but in field experiments inoculations with conidia of M. maydis enhanced severity of the tarspot complex. Fisheye symptoms of the complex naturally appear 2 to 7 days after the manifestation of P. maydis. This is followed a week later by the appearance of M. maydis which became predominant in the lesions and is associated with empty perithecia of P. maydis. In the early stages of the tarspots pycnidia of the anamorph of P. maydis, Linochora sp., could occasionally be observed. Ascomata of M. maydis were rare in the field. Of the 36 genetic materials of CIMMYT tested, 30 developed the fisheye symptom, 4 tarspots only and 2 remained free of symptoms
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00442777
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  • 4
    Digitale Medien
    Digitale Medien
    The effects of aflatoxin B1 on immature germinating maize (Zea mays) embryos (1992)
    Springer
    Mycopathologia 119 (1992), S. 181-190 
    Details
    ISSN: 1573-0832
    Schlagwort(e): aflatoxin B1 ; electron microscopy ; in vitro ; immature maize embryo ; Zea mays
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Immature maize (Zea mays L.) embryos were treated with aflatoxin B1 concentrations, ranging from 0.1 μg ml−1 to 25 μg ml−1. Below 5 μg ml−1 aflatoxin B1, root and shoot elongation was not significantly inhibited. Ultrastructurally, root tip cells showed little deterioration, except a possible diffused clearing in mitochondria and plastids. As the toxin concentration was increased above 5 μgml−1, shoot, and particularly root elongation, was progressively inhibited. Associated with this, there was an apparent decrease in the ribosome population. Furthermore, membranes, particularly the vacuolar membrane, became abnormal and vacuolar distension occurred. At 20 and 25 μg ml−1, these effects were exacerbated, and mitochondria and plastid structure was disrupted. At these concentrations, there was evidence of a disruption in lipid metabolism. The results are discussed in the context of known aflatoxin effects on cellular control mechanisms and ultrastructure in animal systems.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00448817
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  • 5
    Digitale Medien
    Digitale Medien
    Electroporation and PEG delivery of DNA into maize microspores (1992)
    Springer
    Plant cell reports 11 (1992), S. 567-570 
    Details
    ISSN: 1432-203X
    Schlagwort(e): Microspore ; Electroporation ; Transformation ; Zea mays
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The ability to deliver and detect reporter gene activity in maize microspores was tested. Tested expression vectors contained the chloramphenicol acetyl transferase (CAT) gene and one of the following promoter-intron combinations: 1) cauliflower mosaic virus (CaMV 35S), 2) CaMV 35S + maize alcohol dehydrogenase 1 intron 6 (Adh1-I6), 3) maize alcohol dehydrogenase 1 + intron 1 (Adh1-I1), or 4) maize ubiquitin 1 + intron 1 (Ubiq 1-I1) promoter + intron. The expression vectors were delivered into maize microspores using electroporation or polyethylene glycol (PEG). Both methods were effective for delivering free DNA into microspores. Although all four promoters were active in maize protoplasts, only two promoters were active in maize microspores. The CaMV 35S and the Adh1 promoters did not promote gene expression in maize microspore. The CaMV 35S + Adh1-I6 and Ubiq1-I1 promoters produced high levels of CAT activity in maize microspores.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00233094
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  • 6
    Digitale Medien
    Digitale Medien
    Cleavage polyembryony in maize (1992)
    Springer
    Sexual plant reproduction 5 (1992), S. 224-226 
    Details
    ISSN: 1432-2145
    Schlagwort(e): Zea mays ; Maize ; Polyembryony
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Two types of cleavage polyembryony are described in the inbred line VIR 17 of maize. Suspensorial embryony was observed to occur spontaneously. Typical cleavage of the zygotic proembryo occurred spontaneously, but could also be induced by treating the developing caryopses with 2,4-Dichlorophenoxyacetic acid (2,4-D) on the second day after pollination. 2,4-D was active as a decorelative factor also evoking the expression of totipotency in individual proembryonal cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00189815
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  • 7
    Digitale Medien
    Digitale Medien
    Analysis of pollen-tube growth in cultured maize silks (1992)
    Springer
    Sexual plant reproduction 5 (1992), S. 227-231 
    Details
    ISSN: 1432-2145
    Schlagwort(e): Zea mays ; Maize ; Pollen-tube growth regulation ; In vitro pollination
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary In vitro pollen-tube growth in maize was studied using an in vitro pollination system. In the ‘cut-silk’ method, ovaries with silks were placed on medium in vitro, whereafter the silk was cut and the upper part of the silk was pollinated. Pollen tubes were not able to bridge the space between the two silk parts. Even when silk parts were tightly connected, pollen tubes still were not able to pass the cut ends and reach the lower silk part. Pollen-tube growth rates and the direction of tube growth were not influenced by the presence or absence of an ovary. Prepollination did not have any influence on pollen-tube growth rate. Measurements of pollen-tube growth rate also showed that there was no ‘population effect’, i.e. growth rate was not stimulated by pollination with an excess of pollen grains. We found that the direction in which maize pollen grew was determined only by the positioning of the silk hairs.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00189816
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  • 8
    Digitale Medien
    Digitale Medien
    Maturation of maize pollen in vitro (1992)
    Springer
    Plant cell reports 11 (1992), S. 535-539 
    Details
    ISSN: 1432-203X
    Schlagwort(e): Zea mays ; in vitro culture ; in vitro pollen ; pollen germination ; fertilization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Maturation of maize pollen was obtained in male reproductive structures cultured in vitro. Immature tassels containing microspores at the mid-uninucleate to late-binucleate stage of development were excised and spikelets, anthers, and/or isolated microspores were cultured on a medium capable of supporting pollen maturation. Microspore mitosis, culminating in the production of starch-filled, trinucleate pollen capable of germination, was observed after 7–15 days, depending on the genotype and stage at which the cultures were initiated. Up to 100%, 70%, and 20% of the cultured spikelets, anthers, and isolated microspores, respectively, produced mature pollen, which germinated, however, at different frequencies (i.e., spikelets, 50–70%; anthers, 5–10%; microspores, 〈1%). Mature kernels were produced following fertilization with pollen from cultured spikelets and anthers. These procedures provide methods for the in vitro manipulation of a significant phase of the maize life cycle.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00236273
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  • 9
    Digitale Medien
    Digitale Medien
    Matrix-associated DNA from maize is enriched in repetitive sequences (1992)
    Springer
    Plant cell reports 11 (1992), S. 355-358 
    Details
    ISSN: 1432-203X
    Schlagwort(e): Zea mays ; Matrix-associated ; DNA ; repetitive sequences ; DNA loops
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In order to elucidate some features of the topological organization of DNA within the plant nucleus, DNA fragments involved in the attachment of the DNA loops to the nuclear matrix in maize were studied. The matrix-associated DNA from dry embryo and meristematic cells after extensive digestion with DNase I and high salt treatment was about 2% of the total DNA, sized within the range of 50 and 250 bp. This DNA was found to be enriched in repetitive DNA sequences, both for nuclei from dry embryo and meristematic cells. The loop size of the DNA in cells of Zea mays appeared to be between 5 and 25 kbp.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00233365
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  • 10
    Digitale Medien
    Digitale Medien
    The unusual reversion properties of a mitochondrial mutation in the structural gene of subunit I of cytochrome oxidase of Saccharomyces cerevisiae reveal a probable histidine ligand of the redox center (1992)
    Springer
    Current genetics 21 (1992), S. 147-151 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00318474
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  • 11
    Digitale Medien
    Digitale Medien
    Positive cis-acting regulatory sequences mediate proper control of POL1 transcription in Saccharomyces cerevisiae (1992)
    Springer
    Current genetics 21 (1992), S. 183-189 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00336839
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  • 12
    Digitale Medien
    Digitale Medien
    Direct selection of galactokinase-negative mutants of Candida albicans using 2-deoxy-galactose (1992)
    Springer
    Current genetics 21 (1992), S. 203-206 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00336842
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  • 13
    Digitale Medien
    Digitale Medien
    The UGA43 negative regulatory gene of Saccharomyces cerevisiae contains both a GATA-1 type zinc finger and a putative leucine zipper (1992)
    Springer
    Current genetics 21 (1992), S. 301-307 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00351687
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  • 14
    Digitale Medien
    Digitale Medien
    The CCS1 gene from Saccharomyces cerevisiae which is involved in mitochondrial functions is identified as IRA2 an attenuator of RAS1 and RAS2 gene products (1992)
    Springer
    Current genetics 21 (1992), S. 325-329 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00351690
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  • 15
    Digitale Medien
    Digitale Medien
    In vitro mutagenesis of the mitochondrial leucyl-tRNA synthetase of S. cerevisiae reveals residues critical for its in vivo activities (1992)
    Springer
    Current genetics 22 (1992), S. 69-74 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00351744
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  • 16
    Digitale Medien
    Digitale Medien
    Comparative analysis of spontaneous mitotic recombination in [cir 0] and [cir +] strains of the yeast Saccharomyces cerevisiae (1992)
    Springer
    Current genetics 22 (1992), S. 259-265 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00317918
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  • 17
    Digitale Medien
    Digitale Medien
    The REV2 gene of Saccharomyces cerevisiae: cloning and DNA sequence (1992)
    Springer
    Current genetics 22 (1992), S. 277-282 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00317921
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  • 18
    Digitale Medien
    Digitale Medien
    A ten-minute protocol for transforming Saccharomyces cerevisiae by electroporation (1992)
    Springer
    Current genetics 22 (1992), S. 335-336 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00317931
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  • 19
    Digitale Medien
    Digitale Medien
    Field evaluation of N2 fixation and N partitioning in climbing bean (Phaseolus vulgaris L.) using 15N (1992)
    Springer
    Biology and fertility of soils 13 (1992), S. 142-146 
    Details
    ISSN: 1432-0789
    Schlagwort(e): A value ; Common bean ; N remobilization ; Soil N balance ; Atom% 15N excess ; Phaseolus vulgaris ; Zea mays
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary The common bean (Phaseolus vulgaris L.) is generally regarded as a poor N2 fixer. This study assessed the sources of N (fertilizer, soil, and fixed N), N partitioning and mobilization, and soil N balance under field conditions in an indeterminate-type climbing bean (P. vulgaris L. cv. Cipro) at the vegetative, early pod-filling, and physiological maturity stages, using the A-value approach. This involved the application of 10 and 100 kg N ha-1 of 15N-labelled ammonium sulphate to the climbing bean and a reference crop, maize (Zea mays L.). At the late pod-filling stage (75 days after planting) the climbing bean had accumulated 119 kg N ha-1, 84% being derived from fixation, 16% from soil, and only 0.2% from the 15N fertilizer. N2 fixation was generally high at all stages of plant growth, but the maximum fixation (74% of the total N2 fixed) occurred during the interval between early (55 days after planting) and late podfilling. The N2 fixed between 55 and 75 days after planting bas a major source (88%) of the N demand of the developing pod, and only about 11% was contributed from the soil. There was essentially no mobilization of N from the shoots or roots for pod development. The cultivation of common bean cultivars that maintain a high N2-fixing capacity especially during pod filling, satisfying almost all the N needs of the developing pod and thus requiring little or no mobilization of N from the shoots for pod development, may lead to a net positive soil N balance.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00336269
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  • 20
    Digitale Medien
    Digitale Medien
    Regulation of mitochondrial transcription during the stringent response in yeast (1992)
    Springer
    Current genetics 21 (1992), S. 241-247 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00336848
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  • 21
    Digitale Medien
    Digitale Medien
    The gene for cadmium metallothionein from a cadmium-resistant yeast appears to be identical to CUP 1 in a copper-resistant strain (1992)
    Springer
    Current genetics 21 (1992), S. 275-280 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00351682
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  • 22
    Digitale Medien
    Digitale Medien
    Interaction of the yeast pleiotropic drug resistance genes PDR1 and PDR5 (1992)
    Springer
    Current genetics 21 (1992), S. 431-436 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00351651
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  • 23
    Digitale Medien
    Digitale Medien
    One-step transformation of yeast in stationary phase (1992)
    Springer
    Current genetics 21 (1992), S. 83-84 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00318659
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  • 24
    Digitale Medien
    Digitale Medien
    A promoter deletion reduces the rate of mitotic, but not meiotic, recombination at the HIS4 locus in yeast (1992)
    Springer
    Current genetics 21 (1992), S. 109-116 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00318468
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  • 25
    Digitale Medien
    Digitale Medien
    Mitotic hyperploidy for chromosomes VIII and III in Saccharomyces cerevisiae (1992)
    Springer
    Current genetics 21 (1992), S. 309-318 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00351688
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  • 26
    Digitale Medien
    Digitale Medien
    Complementation of the Saccharomyces cerevisiae srb1-1 mutation: an autoselection system for stable plasmid maintenance (1992)
    Springer
    Current genetics 21 (1992), S. 339-344 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00351692
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  • 27
    Digitale Medien
    Digitale Medien
    Adaptation and major chromosomal changes in populations of Saccharomyces cerevisiae (1992)
    Springer
    Current genetics 22 (1992), S. 13-19 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00351736
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  • 28
    Digitale Medien
    Digitale Medien
    Mutational analysis of a variant of ARS1 from Saccharomyces cerevisiae (1992)
    Springer
    Current genetics 22 (1992), S. 175-180 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00351723
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  • 29
    Digitale Medien
    Digitale Medien
    Effects of heat shock and ethanol stress on the viability of aSaccharomyces uvarum (carlsbergensis) brewing yeast strain during fermentation of high gravity wort (1992)
    Springer
    Journal of industrial microbiology and biotechnology 10 (1992), S. 111-116 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF01583843
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  • 30
    Digitale Medien
    Digitale Medien
    Odors influence choice of oviposition sites byDiabrotica virgifera virgifera (Coleoptera: Chrysomelidae) (1992)
    Springer
    Journal of chemical ecology 18 (1992), S. 1227-1237 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Western corn rootworm ; Diabrotica virgifera virgifera ; Coleoptera ; Chrysomelidae ; bacteria ; carbon dioxide ; pheromone ; semiochemicals ; Zea mays
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract FemaleDiabrotica virgifera virgifera LeConte were allowed to choose between oviposition substrates that were and those that were not associated with potential sources of semiochemicals. Females deposited over five times more eggs on moist towelettes that were treated with homogenates of female abdomens than on towelettes treated with distilled water. Similar results were obtained when screening separated the homogenates from the towelettes, indicating that odors alone could elicit the response. In contrast, females did not choose towelettes that had previously been used for oviposition or towelettes containing eggs over unused towelettes. Further tests with homogenates of abdomens and a bacteriostatic agent (sorbate) indicated that the females were probably responding to bacterial odors rather than an oviposition-enhancing pheromone. Four strains of bacteria were isolated from a homogenate of female abdomens; females deposited 4 to 16 times more eggs on substrates with odors of the bacteria than on substrates with odors of uninoculated nutrient agar. In no-choice tests, bacterial odors did not increase the number of eggs deposited per female beetle; however, in choice tests with dishes that tended to retain any beetles that entered, there were more eggs per female (but not more beetles) after 24 hr in dishes with bacterial odors than in those without the odors. Females also chose dishes with odors of excised maize (Zea mays L.) roots or elevated levels of carbon dioxide over “control” dishes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00980076
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  • 31
    Digitale Medien
    Digitale Medien
    Mutational analysis of the ‘conserved region’ of maize streak virus suggests its involvement in replication (1992)
    Springer
    Plant molecular biology 19 (1992), S. 601-610 
    Details
    ISSN: 1573-5028
    Schlagwort(e): geminivirus ; agroinfection ; Zea mays ; large intergenic region (LIR)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Maize streak virus as well as other geminiviruses contain a potential hairpin structure with the conserved sequence TAATATTAC in the loop. We assessed the possible involvement of this structure in replication and symptom induction of the virus. A series of insertion and deletion mutants were analyzed by agroinfection. Deletion of the hairpin or insertions in the conserved sequence abolished symptom development. Viral DNA could not be detected in the infected tissue. However, a mutant with a point mutation in the ‘conserved’ sequence, isolated after inoculation of maize plants with an insertion mutant, was able to replicate and to induce symptoms.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00026786
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  • 32
    Digitale Medien
    Digitale Medien
    An mRNA that specifically accumulates in maize roots delineates a novel subset of developing cortical cells (1992)
    Springer
    Plant molecular biology 20 (1992), S. 821-831 
    Details
    ISSN: 1573-5028
    Schlagwort(e): cortex ; developmental regulation ; in situ hybridization ; organ-specific gene expression ; roots ; Zea mays
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A near full-length cDNA clone (pZRP3) corresponding to an mRNA that accumulates specifically in roots of maize was isolated. The ZRP3 mRNA is ca. 600 nucleotides in length. The amino acid sequence of the predicted polypeptide is rich in leucine (16%), proline (11%), and cysteine (8.5%). The zrp3 gene appears to be expressed exclusively in roots, whereas other ZRP3-related genes are expressed in additional organs of the maize plant. In situ hybridization shows that ZRP3 mRNA accumulation is largely confined to the cells of the cortical ground meristem. Furthermore, accumulation of this mRNA occurs within a distinct subset of cortical cells, the inner three to four cell layers.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00027153
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  • 33
    Digitale Medien
    Digitale Medien
    A DNA polymerase from maize axes: its purification and possible role (1992)
    Springer
    Plant molecular biology 20 (1992), S. 1159-1168 
    Details
    ISSN: 1573-5028
    Schlagwort(e): DNA polymerase ; germination ; Zea mays
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Three different DNA polymerase activities can be resolved by passing a protein extract from 24 h imbibed maize axes through DEAE-cellulose. These activities have been numbered 1, 2 and 3, according to their elution order. One of them, DNA polymerase 2, elutes at 100–120 mM phosphates. This enzyme was further purified by passing it through Heparin-Sepharose, Sephacryl S-300 and DNA cellulose. Purification was nearly 5000-fold. The enzyme needs Mg2+, is stimulated by K+, has an optimum pH of 7.0 and its optimum temperature is 30–37 °C. Specific inhibitors for different types of polymerases, such as aphidicolin, dideoxythymidine triphosphate and N-ethyl maleimide, gave intermediate values of inhibition, making impossible the definition of the type of enzyme purified by its inhibitory pattern. SDS-PAGE indicated the presence of several bands of molecular masses of 28–40, 56 and 15 kDa. Most of these bands could be visualized when proteins from crude extracts were analyzed by western blot, using an antibody against calf thymus DNA polymerase α. A high molecular mass (around 500 kDa) was calculated by western blot of native gels using the same antibody. Finally, specific activity of this enzyme increased 100-fold during maize germination whereas polymerase 3 virtually did not increase. Furthermore, immunoprecipitation experiments with the antipolymerase α-antibody showed a decrease in DNA polymerase activity by 70%. The possibility that polymerase 2 is a replicative enzyme is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00028902
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  • 34
    Digitale Medien
    Digitale Medien
    Stress responses in maize: Sequence analysis of cDNAs encoding glycine-rich proteins (1992)
    Springer
    Plant molecular biology 18 (1992), S. 847-849 
    Details
    ISSN: 1573-5028
    Schlagwort(e): cDNA ; nucleotide sequence ; glycine-rich proteins ; chemical stress ; Zea mays
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00020034
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  • 35
    Digitale Medien
    Digitale Medien
    Multiple ocs-like elements required for efficient transcription of the mannopine synthase gene of T-DNA in maize protoplasts (1992)
    Springer
    Plant molecular biology 20 (1992), S. 219-233 
    Details
    ISSN: 1573-5028
    Schlagwort(e): promoter ; electroporation ; protoplasts ; transient assay ; Agrobacterium ; Ti plasmid ; Zea mays
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Regulatory elements controlling transcriptional activity of the mannopine synthase 2′ promoter (mas 2′) were defined by analysis of deletion mutants in transient expression assays in maize protoplasts. Deletion of the region between −305 and −290 containing sequence similarity to the octopine synthase (ocs) promoter element reduced activity by 67% compared to wild type activity. Less than 1% of the activity remained in 5′ deletions downstream of −153. Inclusion of various heterologous enhancer-like sequences immediately upstream of position −325 increased activity by up to 7.5-fold. Insertion of the −325 to −275 sequence alone, or in combination with heterologous enhancer-like elements, restored activity of some of the 5′-deletion mutants. Restoration of activity was not obtained with mutants deleted past position −127. Our results suggest that a single class of nuclear proteins from maize interact with high affinity at elements designated mas b (−306 to −275; mas 1′ element), d (−127 to −108), and e (−82 to −39; mas 2′ element) as well as the 20 bp element from the ocs promoter. Although the binding site at mas d only appears to accommodate a single protein, this element has the potential to make a weak, but positive, contribution to the activity of the mas 2′ promoter. The binding of nuclear proteins could not be demonstrated at mas a and c, both of which showed limited homology to the ocs element. Mutational evidence suggested that mas a and c may also contribute to mas 2′ transcription.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00014490
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  • 36
    Digitale Medien
    Digitale Medien
    Nucleotide sequence of a region of maize chloroplast DNA containing the 3′ end of clpP, exon 1 of rps12 and rpl20 and their cotranscription (1992)
    Springer
    Plant molecular biology 18 (1992), S. 415-418 
    Details
    ISSN: 1573-5028
    Schlagwort(e): ribosomal protein ; rps12 ; rpl20 ; clpP ; chloroplast genome ; Zea mays
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00034970
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  • 37
    Digitale Medien
    Digitale Medien
    Nitrate reductase transcript is expressed in the primary response of maize to environmental nitrate (1992)
    Springer
    Plant molecular biology 18 (1992), S. 55-64 
    Details
    ISSN: 1573-5028
    Schlagwort(e): cycloheximide ; leaf ; nitrate induction ; nitrate reductase transcript ; root ; scutellum ; Zea mays
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The nitrate induction of NADH:nitrate reductase mRNA in maize roots, scutella and leaves was investigated in the presence and absence of inhibitors of protein synthesis. In the absence of inhibitors, nitrate treatment caused a fairly rapid (2 to 3 h) increase in the level of the nitrate reductase transcript in all tissues. When cytoplasmic protein synthesis was inhibited by cycloheximide, nitrate reductase mRNA was induced by nitrate in all tissues to levels equal to or greater than those found with nitrate treatment alone. Treatment of maize tissues with cycloheximide in the absence of nitrate had only a small effect on the accumulation of the nitrate reductase mRNA. Inhibition of organellar protein synthesis with chloramphenicol also had little or no effect on nitrate-induced nitrate reductase mRNA accumuiation in roots and scutella, but did appear to partially inhibit appearance of transcript in leaves. Excision of scutella in the absence of nitrate was sufficient to cause some accumulation of the nitrate reductase transcript. Since cytoplasmic protein synthesis was not required for expression of nitrate reductase transcripts, induction of these transcripts by nitrate is a primary response of maize to this environmental signal. Thus, it appears that the signal transduction system mediating this response is constitutively expressed in roots, scutella and leaves of maize.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00018456
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  • 38
    Digitale Medien
    Digitale Medien
    cDNA clones encoding Arabidopsis thaliana and Zea mays mitochondrial chaperonin HSP60 and gene expression during seed germination and heat shock (1992)
    Springer
    Plant molecular biology 18 (1992), S. 873-885 
    Details
    ISSN: 1573-5028
    Schlagwort(e): Arabidopsis thaliana ; ATPase ; cpn60 ; developmental regulation ; molecular chaperones ; Zea mays
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Mitochondria contain a nuclear-encoded heat shock protein, HSP60, which functions as a chaperonin in the post-translational assembly of multimeric proteins encoded by both nuclear and mitochondrial genes. We have isolated and sequenced full-length complementary DNAs coding for this mitochondrial chaperonin in Arabidopsis thaliana and Zea mays. Southern-blot analysis indicates the presence of a single hsp60 gene in the genome of A. thaliana. There is a high degree of homology at the predicted amino acid levels (43 to 60%) between plant HSP60s and their homologues in prokaryotes and other eukaryotes which indicates that these proteins must have similar evolutionarily conserved functions in all organisms. Northern- and western-blot analyses indicate that the expression of the hsp60 gene is developmentally regulated during seed germination. It is also heat-inducible. Developmental regulation of the (β-subunit) of F1-ATPase, an enzyme complex that is involved in the cyanide-sensitive mitochondrial electron transport system, indicates that imbibed embryos undergo rapid mitochondrial biogenesis through the early stages of germination. Based on the functional role of HSP60 in macromolecular assembly, these data collectively suggest that the presence of higher levels of HSP60 is necessary during active mitochondrial biogenesis, when the need for this protein is greatest in assisting the rapid assembly of the oligomeric protein structures.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00019202
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  • 39
    Digitale Medien
    Digitale Medien
    Dissection of a pollen-specific promoter from maize by transient transformation assays (1992)
    Springer
    Plant molecular biology 18 (1992), S. 211-218 
    Details
    ISSN: 1573-5028
    Schlagwort(e): pollen-specific gene expression ; promoter analysis ; transient assays ; Tradescantia ; Zea mays
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We have previously reported the isolation and characterization of a gene (Zm 13) from Zea mays which shows a pollen-specific pattern of expression. Stably transformed tobacco plants containing a reporter gene linked to portions of the Zm 13 5′ flanking region show correct temporal and spatial expression of the gene. Here we present a more detailed analysis of the 5′ regions responsible for expression in pollen by utilizing a transient expression system. Constructs containing the β-glucuronidase (GUS) gene under the control of various sized fragments of the Zm13 5′ flanking region were introduced into Tradescantia and Zea mays pollen via high-velocity microprojectile bombardment, and monitored both visually and with a fluorescence assay. The results suggest that sequences necessary for expression in pollen are present in a region from −100 to −54, while other sequences which amplify that expression reside between −260 and −100. The replacement of the normal terminator with a portion of the Zm13 3′ region containing the putative polyadenylation signal and site also increased GUS expression. While the −260 to −100 region contains sequences similar to other protein-binding domains reported for plants, the −100 to −54 region appears to contain no significant homology to other known promoter fragments which direct pollen-specific expression. The microprojectile bombardment of Tradescantia pollen appears to be a good test system for assaying maize and possibly other monocot promoter constructs for pollen expression.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00034950
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  • 40
    Digitale Medien
    Digitale Medien
    Chromosomal and cell size analysis of cold tolerant maize (1992)
    Springer
    Theoretical and applied genetics 84 (1992), S. 798-802 
    Details
    ISSN: 1432-2242
    Schlagwort(e): Zea mays ; C-banding ; Cell size ; Chloroplast number ; Cold tolerance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary C-band number, guard cell length, and chloroplast number per guard cell were determined for eight maize populations. These populations consisted of maize selected for cold tolerance at the University of Nebraska as well as the original unselected populations. The genome size of these populations had previously been determined. C-band number fluctuated concertedly with the changes in genome size indicating that deletions and additions of constitutive heterochromatin occurred during selection, resulting in altered genome sizes. Guard cell size of all the cold tolerant populations was greater than the cell size of the respective nonselected populations. Chloroplast number per guard cell was also higher in all the cold tolerant populations than in their parental populations, but the increases were not statistically significant. The results indicate that changes in genome size that occurred during selection for cold tolerance are the result of changes in amounts of C-band heterochromatin and that the selection process results in an increase in cell size in the cold tolerant populations.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00227387
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  • 41
    Digitale Medien
    Digitale Medien
    Mechanical release and lectin labeling of maize root protoplasts (1992)
    Springer
    Protoplasma 169 (1992), S. 49-56 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Lectin ; Plasma membrane ; Protoplast isolation ; Zea mays
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary An improved method for the mechanical release of protoplasts from plant tissues is described. The historically-low yield of mechanically-released protoplasts is greatly increased by use of a simple electrically-driven tissue sheer and by optimization of various other steps in the procedure. As counted by light microscopy of a purified preparation, the number of mechanically-released protoplasts obtained is about 6×104 per gram fresh weight of cortical tissue from the primary root of maize (Zea mays L. WF9×Mo 17) seedlings. Nuclear staining of the preparation, however, shows that about half of these protoplasts lack a nucleus and thus are actually subprotoplasts. Comparison of lectin binding to the plasma membranes of mechanically-and enzymatically-released protoplasts shows that both types contain binding sites forRicinus communis agglutinin. Binding sites for peanut (Arachis hypogaea) agglutinin are not naturally present on mechanically-released protoplasts but are generated by exposure to a mixture of Cellulysin and Pectolyase Y-23, the cell wall-degrading enzymes used to prepare enzymatically-released protoplasts.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01343369
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  • 42
    Digitale Medien
    Digitale Medien
    Plant cell wall architecture is revealed by rapid-freezing and deep-etching (1992)
    Springer
    Protoplasma 167 (1992), S. 33-42 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Daucus carota ; Zea mays ; Vigna radiata ; Helicoidal cell walls ; Polylamellate cell walls ; Rapid-freeze deep-etch
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary This paper reports on preliminary investigations into the structure of cell walls of varying complexity as revealed by the rapidfreeze deep-etch technique. Three cell types from different species were examined in order to compare the three-dimensional arrangement of random, polylamellate and helicoidal walls. Each cell type displayed a distinctive level of organisation with respect to the cellulose microfibrils and the matrix material. In polylamellated walls, the microfibrils within each layer were linked to each other by 16–20 nm long side chains regularly spaced along the length of the microfibril. In helicoidal walls, the shifting of the microfibrils could cleary be seen, yet no recognisable structures were observed which could mediate this movement.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01353578
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  • 43
    Digitale Medien
    Digitale Medien
    Effect of thefloury-2 locus on protein body formation during maize endosperm development (1992)
    Springer
    Protoplasma 171 (1992), S. 123-133 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF01403727
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  • 44
    Digitale Medien
    Digitale Medien
    Increases in binding protein (BiP) accompany changes in protein body morphology in three high-lysine mutants of maize (1992)
    Springer
    Protoplasma 171 (1992), S. 142-152 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Endosperm ; Zea mays ; Immunolocalization ; Rough endoplasmic reticulum ; Binding protein ; Protein bodies
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary A maize 75 kDa protein recently has been identified as a plant homolog of the mammalian binding protein (BiP). To better understand the function of BiP in protein body formation in maize endosperm, immunomicroscopy studies were conducted on three maize endosperm mutants, floury-2, Mucronate, and Defective endosperm-B 30, in which the level of BiP is highly elevated. Our results showed that protein body morphology in all three mutants was altered. In addition, BiP was localized in both the ER and peripheral regions of the abnormal protein bodies. The degree to which protein body morphology differed from normal was positively correlated with increased amounts of BiP. In addition, the accumulation of BiP in abnormal protein bodies increased with protein body maturation. In the three endosperm mutants, the arrangement of zeins within protein bodies had been perturbed, yet none of the specific zein subclasses exhibited the staining pattern found for BiP. The association of BiP with abnormal packaging of proteins in protein bodies may reflect a biological function to mediate protein folding and assembly in maize endosperm.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01403729
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  • 45
    Digitale Medien
    Digitale Medien
    A new member of the adenylate kinase family in yeast: PAK3 is highly homologous to mammalian AK3 and is targeted to mitochondria (1992)
    Springer
    Molecular genetics and genomics 233 (1992), S. 363-371 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00265432
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  • 46
    Digitale Medien
    Digitale Medien
    Reactivation of Mutator transposable elements of maize by ultraviolet light (1992)
    Springer
    Molecular genetics and genomics 234 (1992), S. 353-360 
    Details
    ISSN: 1617-4623
    Schlagwort(e): Zea mays ; Somatic instability ; Bronze-2 ; Genomic shock ; Pollen
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary After epigenetic loss of Mutator activity, the family of Mu elements in Zea mays becomes immobile and highly methylated; in addition, Mu9, the presumptive autonomous regulatory element, is transcriptionally silent and its copy number decreases in successive crosses to non-Mutator lines. Spontaneous reactivation, scored as restoration of somatic instability of potentially mutable alleles of Bronze-2, of such cryptic Mutator lines is rare, occurring with a frequency of about 10−4. Irradiation of pollen with 254 nm ultraviolet light increases reactivation rate in the progeny kernels by up to 40-fold. Accompanying reactivation, the copy number of Mu9 elements increased, two-fold in one line and 20 to 40-fold in a second line. Reactivation may involve direct DNA damage or immediate physiological stress in the treated pollen.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00538694
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  • 47
    Digitale Medien
    Digitale Medien
    Molecular cloning of the imidazoleglycerolphosphate dehydratase gene of Trichoderma harzianum by genetic complementation in Saccharomyces cerevisiae using a direct expression vector (1992)
    Springer
    Molecular genetics and genomics 234 (1992), S. 481-488 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00538709
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  • 48
    Digitale Medien
    Digitale Medien
    Targeting sequences of the two major peroxisomal proteins in the methylotrophic yeast Hansenula polymorpha (1992)
    Springer
    Molecular genetics and genomics 235 (1992), S. 269-278 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00279370
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  • 49
    Digitale Medien
    Digitale Medien
    STE50, a novel gene required for activation of conjugation at an early step in mating in Saccharomyces cerevisiae (1992)
    Springer
    Molecular genetics and genomics 236 (1992), S. 145-154 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00279653
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  • 50
    Digitale Medien
    Digitale Medien
    Structure and regulation of yeast HEM3, the gene for porphobilinogen deaminase (1992)
    Springer
    Molecular genetics and genomics 234 (1992), S. 233-243 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00283844
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  • 51
    Digitale Medien
    Digitale Medien
    Effect of donor copy number on the rate of gene conversion in the yeast Saccharomyces cerevisiae (1992)
    Springer
    Molecular genetics and genomics 235 (1992), S. 97-103 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00286186
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  • 52
    Digitale Medien
    Digitale Medien
    Isolation and phenotypic analysis of conditional-lethal, linker-insertion mutations in the gene encoding the largest subunit of RNA polymerase II in Saccharomyces cerevisme (1992)
    Springer
    Molecular genetics and genomics 232 (1992), S. 408-414 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00266244
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  • 53
    Digitale Medien
    Digitale Medien
    TheSaccharomyces cerevisiae GAM2/SIN3 protein plays a role in both activation and repression of transcription (1992)
    Springer
    Molecular genetics and genomics 233 (1992), S. 327-330 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00587597
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  • 54
    Digitale Medien
    Digitale Medien
    Regulated transcription of the maize Bronze-2 promoter in electroporated protoplasts requires the C1 and R gene products (1992)
    Springer
    Molecular genetics and genomics 233 (1992), S. 379-387 
    Details
    ISSN: 1617-4623
    Schlagwort(e): Bz2 gene ; Transcriptional regulation ; Anthocyanin pathway ; Transient assay ; Zea mays
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The putative maize transcription factor genes R and C1 are required for expression of reporter genes with promoters from the Bz1 and A1 genes, which encode enzymes required for anthocyanin biosynthesis in maize. Bz2 is another anthocyanin biosynthetic gene; we show that expression of a reporter gene from the Bz2 promoter also requires R and C1 when the fusion construct is introduced into maize kernels by particle gun bombardment. When electroporated into maize protoplasts from a suspension cell line not synthesizing anthocyanins, reporter genes with Bz2, Bz1, and A1 promoters are expressed only when both R and C1 expression plasmids are co-electroporated. Electroporation of R and C1 expression plasmids also induces the endogenous genes required for anthocyanin synthesis, resulting in pink protoplasts within 24 h. RNase protection analysis demonstrates that accumulation of mRNA from the endogenous Bzl and Bz2 genes absolutely requires introduced R and C1. In time-course experiments there is a delay of 3–6 h before the Bz2 promoter is activated, supporting the proposed role for R- and C1-encoded proteins in transcriptional control. An excess of R relative to C1 suppresses expression of A1, Bz1, and Bz2 promoters, suggesting an interaction between the R and C1 proteins.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00265434
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  • 55
    Digitale Medien
    Digitale Medien
    Mechanism of Ds1 excision from the genome of maize streak virus (1992)
    Springer
    Molecular genetics and genomics 233 (1992), S. 388-394 
    Details
    ISSN: 1617-4623
    Schlagwort(e): Viral vector ; Transposable element ; Zea mays ; Agroinfection
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary We have previously shown that the maize transposable element Ds1 introduced into maize plants by agroinfection can be excised from the genome of geminivirus maize streak virus (MSV). Excision depended strictly on the presence of an active Ac element in the plants. In this study, the excision products or “footprints” left in the MSV genome after Ds1 excision were extensively characterized and the effects of flanking sequences on Ds1 excision were analysed. Most types of footprints obtained were comparable to those described for Ds1 excision in the maize genome, and could be explained by the models proposed for excision of plant transposable elements. In two revertants, however, some terminal sequences of the Ds1 element were found to have been left behind at the excision site. The finding of this novel type of Ds1 footprint indicated that gene conversion events occurred during and/or after Ds1 excision from the MSV genome. A partial deletion of one copy of the 8 by duplications flanking the Ds1 element had no effect on the frequency or on the types of footprints of Ds1 excision from the MSV genome. Thus, the duplicated 8 by sequences flanking the transposable element are not involved in Ds1 excision. These results, as well as a statistical analysis of the modifications of the bases flanking the Ds1 element after excision, are discussed in terms of excision models.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00265435
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  • 56
    Digitale Medien
    Digitale Medien
    Functional analysis of the — 300 region of maize zein genes (1992)
    Springer
    Molecular genetics and genomics 231 (1992), S. 369-374 
    Details
    ISSN: 1617-4623
    Schlagwort(e): Zea mays ; Transcription ; Transformation ; Endosperm ; Tissue culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary A 43 by fragment containing the — 300 region upstream control element common to the endosperm expressed zein genes of Zea mays L. has been analyzed by in vivo and in vitro techniques. Transient transformation studies with protoplasts from a maize endosperm culture indicate that the element positively affects CaMV 35S promoter-driven gene expression, and that this effect is both orientation- and position-dependent. Band-shift and Southwestern blotting experiments demonstrate that the element is specifically bound by different sets of DNA-binding proteins from seedling and endosperm nuclei. A 2 by substitution within the most conserved region of the element both reduces the stimulatory effect on transcription and alters the binding of nuclear proteins from both tissues.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00292705
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  • 57
    Digitale Medien
    Digitale Medien
    Structural and functional analysis of theBz2 locus ofZea mays: characterization of overlapping transcripts (1992)
    Springer
    Molecular genetics and genomics 233 (1992), S. 269-277 
    Details
    ISSN: 1617-4623
    Schlagwort(e): Zea mays ; Bz2 locus ; Natural antisense transcripts ; Transposable elements ; Gene family
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Analysis of the transcription pattern of theBz2 locus revealed that overlapping transcripts are derived from opposite DNA strands. The most abundant transcript (sense transcript) has an open reading frame coding for a protein of 241 amino acids, whilst in the antisense orientation no open reading frame has been detected; the antisense transcripts are detected only in those tissues that show high levels of sense transcript. Particle gun experiments indicate that the sense transcript is sufficient to provide theBz2 function. The promoter driving the sense transcript contains the elements usually found in front of eukaryotic genes. In addition an element with similarity to theC1 andR binding sites identified in theBz1 promoter is found. Further upstream in the promoter region a transposon-like insertion has been identified. This element has features similar to members of theAc/Ds transposable element family. The putativeBz2 protein shows similarity to various other plant proteins and to anEscherichia coli protein. All related proteins have in common the fact that they are involved in stress responses.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00587588
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  • 58
    Digitale Medien
    Digitale Medien
    In vivo demonstration of acid phosphatase activity in the rhizosphere of soil-grown plants (1992)
    Springer
    Plant and soil 144 (1992), S. 199-205 
    Details
    ISSN: 1573-5036
    Schlagwort(e): acid phosphatase ; ectoenzymes ; naphthyl phosphate ; Picea abies ; rhizosphere ; Zea mays
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract For in vivo demonstration of acid phosphatase activity in the rhizosphere of soil-grown plants filter papers were treated with a mixture of 1-naphthyl phosphate as substrate and the diazonium salt Fast Red TR as an indicator. After enzymatic hydrolysis, 1-naphthol forms a red complex with Fast Red TR. This method was applied to 8-day old maize plants and 3-year old Norway spruce plants growing in rhizoboxes in soil under non-sterile conditions. The treated filter paper is placed at the surface of roots and soil and acid phosphatase activity is visualized as a red-coloured ‘root print’ on the filter paper. The method can be used as a qualitative analysis of acid phosphatase in the rhizosphere. It also allows a rough estimate of phosphatase activity in different root zones.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00012876
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  • 59
    Digitale Medien
    Digitale Medien
    Divergent full-sib recurrent selection for germination at low temperature in a maize population (1992)
    Springer
    Euphytica 64 (1992), S. 21-29 
    Details
    ISSN: 1573-5060
    Schlagwort(e): cold tolerance ; correlated responses ; germination ; kernel type ; kernel weight ; recurrent selection ; Zea mays
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Four cycles of divergent full-sib recurrent selection for the ability to germinate at low temperature were conducted in a maize (Zea mays L.) F2 population. The selection criterion was the high (H) or the low (L) value in algebraic terms of the difference (DG) between germination percentage at 9.5°C (G9.5) detected 19 days after sowing and germination percentage at 25°C (G 25) seven days after sowing; both traits were evaluated in a controlled environment (germinator). Direct and correlated responses estimated during the course of selection were in accordance with those evaluated at the end. Selection for H led to populations with higher DG values, while the reverse was noted for L; differences between H and L populations increased in successive selection cycles, though divergence tended to level off. Selection for H also resulted in higher G 9.5 (day 19), shorter germination time and more flinty kernels, while selection for L led to responses in the opposite direction as well as to a lower G 9.5 detected 37 days after sowing (i.e. at the end of germination). In contrast, responses were negligible for G 25 and varied erratically from one cycle to another for kernel weight.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00023534
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  • 60
    Digitale Medien
    Digitale Medien
    Evaluation of in vitro selection regimes for a mitochondrial trait (methomyl resistance) in cms-T maize (1992)
    Springer
    Plant cell, tissue and organ culture 28 (1992), S. 129-137 
    Details
    ISSN: 1573-5044
    Schlagwort(e): cms-T ; in vitro selection ; methomyl resistance ; mitochondrial mutation ; Zea mays
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Several factors affecting the success of selection in plant populations were examined for their relevance to in vitro selection. Three in vitro selection schemes and two growth assessment procedures were evaluated for effectiveness in selecting for a mitochondrial trait in maize: resistance to the insecticidal compound methomyl. Regenerable maize callus was derived from immature embryos of the three-way hybrid P39/IL766A2 x W182BN containing Texas male sterile cytoplasm (cms-T). Either low, gradually increasing, or high selection pressures were used to grow callus over a period of 3–5 months. There was no significant difference in recovery of resistant plants using these 3 methods. Growth of callus on medium containing methomyl was assessed by increase in fresh weight during the final month of selection or by increase in number of callus pieces over the course of selection. These quantitative measures of growth were unreliable indicators for gain in resistance within the callus population. A procedure for recovery of methomyl resistant and male-fertile cms-T plants is suggested.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00055507
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  • 61
    Digitale Medien
    Digitale Medien
    An alignment of 17 deduced protein sequences from plant, fungi, and ciliate H+-ATPase genes (1992)
    Springer
    Journal of bioenergetics and biomembranes 24 (1992), S. 309-317 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00768851
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  • 62
    Digitale Medien
    Digitale Medien
    Relationship of embryogenic competence in maize (Zea mays L.) leaves to mitotic activity, cell cycle and nuclear DNA content (1992)
    Springer
    Plant cell, tissue and organ culture 31 (1992), S. 215-221 
    Details
    ISSN: 1573-5044
    Schlagwort(e): cell cycle ; DNA content ; embryogenic competence ; flow cytometry ; mitotic activity ; somatic embryogenesis ; Zea mays
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Embryogenic competence of maize (Zea mays L.) leaf tissues was studied with regard to leaf age, distance from leaf base, mitotic activity, 2C nuclear DNA content, and the distribution of cells within the cell cycle. The highest embryogenic competence was observed in the first segment of the second innermost leaf. In a succession of 8 mm segments from the leaf base, the frequency of cells in the G0/G1 phase of the cell cycle and mitotic activity decreased with leaf age and with the distance from leaf base. No significant differences in 2C nuclear DNA content were found for leaf segments of different age and position. The mean 2C nuclear DNA content was 5.74 pg. The results suggested that the loss of embryogenic competence in mature maize leaf tissues is not related to changes in nuclear DNA content, and that the competence is not simply related to a certain distribution of cells within the cell cycle or to a certain level of mitotic activity.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00036227
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  • 63
    Digitale Medien
    Digitale Medien
    Effect of ferulic acid on growth and hydrolytic enzyme activities of germinating maize seeds (1992)
    Springer
    Journal of chemical ecology 18 (1992), S. 1981-1990 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Allelopathy ; ferulic acid ; amylase ; maltase ; invertase ; acid protease ; acid phosphatase ; Zea mays ; growth ; root ; shoot
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Ferulic acid was tested for its effect on the growth of root and shoot, fresh and dry weights, and hydrolytic enzyme activities of germinating maize seeds. The results showed that root growth was inhibited more than shoot growth. A significant reduction in the activities of hydrolytic enzymes was also observed, which reflects a mechanism of action for the natural growth inhibitors, which may include other phenolic compounds.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00981921
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  • 64
    Digitale Medien
    Digitale Medien
    Phenylacetic acid as a phytotoxic compound of corn pollen (1992)
    Springer
    Journal of chemical ecology 18 (1992), S. 897-905 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Pollen ; corn ; Zea mays ; teosinte ; Zea mexicana ; allelopathy ; phenylacetic acid ; phytotoxicity ; Amaranthus leucocarpus ; Echinochloa crusgalli
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Phenylacetic acid (PAA), one of the phytotoxic compounds in corn (Zea mays) pollen, was identified by GC-MS and by direct comparison with a pure commercial sample of PAA. Bioassays were carried out by testing whole pollen, methylene chloride extract of the pollen, and pure PAA on germination and radical growth ofAmaranthus leucocarpus andEchinochloa crusgalli. The effect of corn pollen was compared with that ofZea mexicana (Teosinte), one of the wild relatives of cultivated maize.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00988330
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  • 65
    Digitale Medien
    Digitale Medien
    Cluster analysis of RFLP data from related maize inbred lines of the BSSS and LSC heterotic groups and comparison with pedigree data (1992)
    Springer
    Euphytica 60 (1992), S. 139-148 
    Details
    ISSN: 1573-5060
    Schlagwort(e): coancestry coefficient ; genetic similarity ; maize ; Zea mays
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary In this study, 31 elite inbred lines of maize (Zea mays L.) were analyzed with 149 clone-enzyme combinations for their respective RFLP profiles. Objectives were (1) to determine the utility of RFLPs for estimation of genetic similarties among 16 inbred lines from the Iowa Stiff Stalk Synthetic (BSSS) and among 15 inbred lines from the Lancaster Sure Crop (LSC) heterotic groups and (2) to compare genetic similarities based on molecular markers with those based on pedigree information. Coefficients of genetic similarity (GS) and coancestry (f) between pairs of lines from the same heterotic group were calculated from RFLP and pedigree data, respectively. For lines from the BSSS heterotic group, cluster analyses based on RFLP and pedigree data revealed similar associations. GS and f values were closely correlated (r=0.70) for related BSSS lines. For lines from the LSC heterotic group, considerable discrepancies existed between the GS and f values, especially for those pairs involving inbreds Va22 and Lo924. Effect of selection and/or erroneous pedigree records are discussed as possible explanations for the low correlation of GS and f values (r=0.07) for related LSC lines. RFLPs seem useful for investigation of relationships among maize inbreds, verification of pedigree records, and quantification of the degree of relatedness.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00029669
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  • 66
    Digitale Medien
    Digitale Medien
    Structural observations during androgenic microspore culture of the 4c1 genotype of Zea mays L. (1992)
    Springer
    Euphytica 65 (1992), S. 61-69 
    Details
    ISSN: 1573-5060
    Schlagwort(e): androgenesis ; in vitro culture ; maize ; microspores ; Zea mays
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary The capacity of the maize genotype 4c1 to regenerate microcalli and embryos from cultured microspores has been examined by comparing various cold pretreatments and culture media, using microspores and pollen at different stages of development. Viability of cultured cells was tested with FDA and their development was traced with light and fluorescence microscopy using DAPI as a nuclear dye. It was found that a pre-incubation of dissected flowers floating in a liquid nutrient medium at 8°C during 10–14 days was most successful for the induction of cell division. Among the developmental stages tested only the microspores appeared to regenerate. Subculture at 25°C in the same liquid medium, supplemented with 0.1 mg/l TIBA, gave highest rates of microspore division, i.e. up to 70% at 4 to 6 days of culture. All pathways described earlier for maize androgenic embryogenesis were observed within the 4c1 genotype. Symmetric divisions occurred in cultured microspores but most frequently asymmetric divisions lead to the formation of microcalli within 12 days of culture. In at least 60% of all dividing microspores cells were derived from the generative nucleus. Microcalli further developed either into loose or compact calli. Compact calli formed embryo-like structures.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00022200
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  • 67
    Digitale Medien
    Digitale Medien
    The impact of genotype x soil texture interaction on the efficiency of selection for yield in maize (Zea mays L.) (1992)
    Springer
    Euphytica 61 (1992), S. 61-65 
    Details
    ISSN: 1573-5060
    Schlagwort(e): population improvement ; maize ; Zea mays ; honeycumb selection ; adaptability ; stability ; yield
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary This study was undertaken to investigate the implications of genotype x soil texture interaction on response to selection in maize. Mass honeycomb selection for yield was applied for 11 cycles from the F2 of the single cross maize hybrid F68×NE2 in a field B with silty-clay-loam soil texture. Response to selection compared to the original single cross hybrid was estimated both in absence of competition and under solid stand in the selection field B and in a nearby field A differing in soil texture (clay-loam). A strong crossover type of interaction occurred both under solid stand and in the absence of competition in the two tests the improved population outyielded the hybrid in field B in the two densities, but lagged behing the hybrid in field A. The results suggest that interaction between genotype and soil texture might affect efficiency of selection detrimentally unless provision is taken for parallel selection early in the crop improvement program in fields differing in soil texture.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00035547
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  • 68
    Digitale Medien
    Digitale Medien
    Segregation of genetic markers among wheat doubled haploid lines derived from wheat x maize crosses (1992)
    Springer
    Euphytica 65 (1992), S. 145-152 
    Details
    ISSN: 1573-5060
    Schlagwort(e): doubled haploid ; genetic marker ; wheat ; wheat x maize crosses ; Triticum aestivum ; Zea mays
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Wheat doubled haploid (DH) lines were produced from the F1 hybrid, Fukudo-komugi x Oligo Culm, through intergeneric crosses between wheat and maize. F2 plants and 203 DH lines were analyzed for the segregation of the eight genetic markers, namely, grain proteins, grain esterases, GA-insensitivity and glume traits. The segregation in the F2 plants fitted to the expected ratios. No deviation was observed among the DH lines, either, except for the glume pubescence. The result indicates the absence of correlation between the markers investigated and the efficiency of embryo formation in the DH lines.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00022576
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  • 69
    Digitale Medien
    Digitale Medien
    Genetic improvement of cell-wall digestibility in forage maize (Zea mays L.). I. Performance of inbred lines and related hybrids (1992)
    Springer
    Euphytica 65 (1992), S. 187-194 
    Details
    ISSN: 1573-5060
    Schlagwort(e): forage maize ; Zea mays ; breeding ; nutritive value ; cell-wall digestibility ; stalk quality
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary The current study deals with genetic improvement of the nutritive value of forage maize. In separate field trials, maize inbred lines without the brown midrib trait and derived hybrids were evaluated for stalk quality as well as some other agronomic traits. The aim was to relate the performance of lines and hybrids. Quality traits studied were the contents of ash and cell walls expressed as percentage of dry matter and the digestibilities of organic matter and cell walls (stalk-dv% and stalk-dcw%, respectively). The performance of hybrids was established in a trial at two locations with three replicates per location and the performance of lines at one location in an unreplicated trial. The range for stalk-dcw% was about 10 percentage units between hybrids and 15 percentage units between inbred lines. Stalk-dcw% had of all quality traits of hybrids the highest broad-sense heritability (h 2=0.74), and determined about 80% of the variation in stalk-dv%. The only stalk quality trait where a significant correlation was found between the mean hybrid performance and the corresponding midparent value was stalk-dcw% (r=0.70, P〈0.01). In conclusion, stalk-dcw% proved to be the only stalk quality trait worth evaluating at the inbred line level in a breeding programme aimed at producing commercial hybrid varieties of forage maize.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00023082
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  • 70
    Digitale Medien
    Digitale Medien
    Variation among maize (Zea mays L.) accessions of Bendel State, Nigeria. Multivariate analysis of agronomic data (1992)
    Springer
    Euphytica 66 (1992), S. 65-71 
    Details
    ISSN: 1573-5060
    Schlagwort(e): cluster analysis ; principal component analysis ; accession ; landraces ; Zea mays ; maize ; dendrogram ; variation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Two multivariate techniques were used to characterize 30 maize accessions collected from three ecological zones of Bendel State, Nigeria. Differentiation of the 30 accessions into five distinct groups was achieved with the unweighted variable group method of the average linkage cluster analysis of 34 agronomic characters. Four of the taxonomic groups contained at least three accessions each, while a fifth group contained only one. The single accession contained in the fifth group was characterised by very early maturity, deeply pigmented leaves and ear husks and short statured plants. Clustering of the accessions into different phenetic groups followed substantially along geographical and traditionally trading routes. A few cases of overlapping of accessions from different geographical locations were obtained. Principal component analysis revealed that days to 50% tasseling and silking, number of nodes/plant, ear length, ear weight, leaf width, and kernel colour were the principal discriminatory characters that differentiated the accessions. Sixty-four percent of the total variation among the 34 characters were accounted for by the first five principal components while the first and second components accounted for 26 and 14 respectively.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00023509
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  • 71
    Digitale Medien
    Digitale Medien
    Differential effect of temperature on mitrochondrial activity in shoots from freshly harvested and moderately aged kernels of maize (Zea mays L.) (1992)
    Springer
    Plant growth regulation 11 (1992), S. 267-271 
    Details
    ISSN: 1573-5087
    Schlagwort(e): Mitochondria ; respiration ; seed ageing ; seed storage ; temperature ; Zea mays
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract This paper reports on a study of mitochondrial activity in etiolated shoots of freshly harvested and moderately aged kernels of maize. Activity was investigated after incubation at a favourable temperature (25°C), sub-optimal temperature (13°C) and after a heat shock (46°C for 2h). Although impaired mitochondrial activity in shoots from moderately aged maize kernels was not detected at 25°C, deficiencies became evident under low temperature stress (13°C). State 3 oxygen uptake, cyanide-insensitive oxygen uptake and cytochrome oxidase activity were lower in mitochondria from these shoots at 13°C than in mitochondria from shoots of freshly harvested kernels at this temperature. After a heat shock, cyanide-insensitive oxygen uptake was higher, and cytochrome oxidase activity lower, in shoots of aged kernels than in shoots of fresh kernels. No significant differences in ADP: O ratio or succinate dehydrogenase activity occurred between mitochondria from shoots of the two seed lots in any of the temperature treatments.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00024565
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  • 72
    Digitale Medien
    Digitale Medien
    6-Methoxy-2-benzoxazolinone: A semiochemical for host location by western corn rootworm larvae (1992)
    Springer
    Journal of chemical ecology 18 (1992), S. 931-944 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Diabrotica virgifera virgifera ; 6-methoxy-2-benzoxazolinone ; hydroxamic acids ; semiochemical ; attractants ; western corn rootworm ; host location ; Coleoptera ; Chrysomelidae ; Zea mays ; kairomone
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract A bioassay-driven sequential fractionation scheme was used to isolate all portions of a crude dichloromethane corn seedling extract behaviorally active to larvae of the western corn rootworm,Diabrotica virgifera virgifera LeConte. 6-Methoxy-2-benzoxazolinone (MBOA) was identified as one of the most important components of an attractive crude corn extract. MBOA was found on or in the intact root tissues by injecting an extract of undamaged roots onto an HPLC immediately after extraction. MBOA was demonstrated to be volatile and functions as a semiochemical in conjunction with carbon dioxide in host location by western corn rootworm larvae, which are oligophagous on the roots of maize and several other species of grasses. Because MBOA occurs almost exclusively in maize and other grasses, it offers a simple way for the larvae to distinguish possible hosts from non-hosts. MBOA has previously been reported as a chemical defense against other insect species. This is the first report in grasses of a secondary compound that is toxic or a deterrent to nonadapted insect herbivores but that is used as a semiochemical in host location by a specialist insect species.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00980054
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  • 73
    Digitale Medien
    Digitale Medien
    Temporal relationships betweenZea mays, ostrinia nubilalis (Lep.: Pyralidae) and endophyticBeauveria bassiana (1992)
    Springer
    BioControl 37 (1992), S. 525-536 
    Details
    ISSN: 1573-8248
    Schlagwort(e): Beauveria bassiana ; Ostrinia nubilalis ; endophytic relationship ; biological control ; insect pathology ; Zea mays ; Beauveria bassiana ; Ostrinia nubilalis ; lutte biologique ; relation endophyte ; pathologie de l'insecte ; Zea mays
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Beschreibung / Inhaltsverzeichnis: Résumé Le champignon entomopathogène,Beauveria bassiana (Balsamo) Vuillemin a été épandu sur maïs, au stade cornet (V7) par application foliaire d'une formulation granulée de grits de maïs contenant des conidies ou par injection d'une suspension de conidies. Toutes les plantes ont été infestées à l'aide de larves de la Pyrale du maïs,Ostrinia nubilalis, au stade V7 (cornet), V12 (fin de stade cornet), ou V17 (apparition de la panicule). Les plantes infestées au stade cornet et à la fin du stade cornet ont eu significativement plus de chenilles de Pyrale en train de miner que les plantes infestées au stade début de panicule mâle. Le pourcentage de plantes infestées parB. bassiana n'était pas significativement différent entre ces 3 stades phénologiques. Au fur et à mesure que les plantes se développaient,B. bassiana était isolé de différentes parties de la plante, la moelle étant plus souvent infestée que les ligules. Les applications foliaires deB. bassiana ont entraîné la destruction immédiate de la pyrale chez les plantes infestées au stade cornet. La baisse de l'efficacité deB. bassiana aux stades intermédiaires par comparaison avec son efficacité au moment de la récolte est discutée.
    Notizen: Abstract The entomopathogenic fungus,Beauveria bassiana (Balsamo) Vuillemin, was applied to whorl-stage (V7) corn,Zea mays L., by foliar application of a granular formulation of corn grits containing conidia or by injection of a conidial suspension. All plants were infested with European corn borer larvae,Ostrinia nubilalis (Hübner), at the V7 (whorl), V12 (late-whorl), or V17 (pretassel) stage of plant development. Plants infested at whorl and late-whorl stages had significantly more European corn borer tunneling than did plants infested at the pretassel stage. The percentage of plants colonized byB. bassiana did not differ significantly among the whorl, late-whorl, and pretassel stages. As the plants matured,B. bassiana was isolated from different plant areas, with the pith more frequently colonized than the leaf collars. Foliar application ofB. bassiana provided immediate suppression ofO. nubilalis in those plants infested at whorl stage. The reduced efficacy ofB. bassiana at the intermediate plant stages relative to efficacy at harvest is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02372322
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