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  • Animals  (7,946)
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  • 1
    ISSN: 1476-5535
    Keywords: Penicillin V acylase ; Beijerinckia indica var.penicillanicum ; Mutation ; Solvent effect
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary Beijerinckia indica var.penicillanicum mutant UREMS-5, producing 168% more penicillin V acylase, was obtained by successive treatment with UV, γ-irradiation and ethylmethane sulfonate. Penicillin V acylase production by the mutant strain was resistant to catabolite repression by glucose. Incorporation of glucose, sodium glutamate and vegetable oils in the medium enhanced enzyme production. The maximum specific production of penicillin V acylase was 244 IU/g dry weight of cells. Effect of solvents on hydrolysis of penicillin V by soluble penicillin V acylase and whole cells was studied. Methylene chloride, chloroform and carbon tetrachloride significantly stimulated the rate of penicillin V hydrolysis by whole cells.
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  • 2
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    Journal of industrial microbiology and biotechnology 8 (1991), S. 99-106 
    ISSN: 1476-5535
    Keywords: Mutation ; UV ; Biodegradation ; Chlorinated organic compound
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary In this study, a continuous-flow UV-induced mutation (CUM) device and the CUM device coupled to a selector (CUMS) reactor were fabricated and tested for their ability to enhance the probability of obtaining populations capable of chlorinated organic biodegradation. A mixed culture of bacteria were used as the starting strain for both the CUM and CUMS processes. Populations were obtained from the CUM and CUMS systems capable of 4-chlorobenzoic acid, 2,4-dichlorobenzoic acid and chlorendic acid biodegradation. Non-UV irradiated population served as controls for the experiments and did not demonstrate chlorinated organic biodegradation over the test duration.
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  • 3
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    Current genetics 18 (1990), S. 441-445 
    ISSN: 1432-0983
    Keywords: Neurospora crassa ; Mutation ; RIP phenomenon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In the further analysis of a cross in which the mis-sense allele, am 3, of the Neurospora crassa am (glutamate dehydrogenase) gene was present in one parent together with two ectopic wild-type gene copies, one ascus was identified in which the two ectopic copies had been inactivated by the RIP process whereas the am 3 allele continued to produce its characteristic enzyme variety in active, but heat-sensitive, form. The am 3 allele had also acquired a new HindIII restriction site. It had no detectable methylation. The mutations responsible respectively for the new restriction site and the modified enzyme properties were separated from each other, and from the original am 3 mutation, by selecting for intragenic recombination on either side of the am 3 site. In this way two new effectively wild-type alleles were generated, one characterised by its heat-sensitive and kinetically modified enzyme product and the other by a new HindIII site. These results demonstrate that the RIP phenomenon can be a source of new functional alleles.
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  • 4
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    Journal of molecular evolution 19 (1983), S. 214-218 
    ISSN: 1432-1432
    Keywords: Codon: anticodon adaptation ; Mutation ; Selection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Synonymous codon usage frequencies, derived from cDNA clone sequences, were compared for several sets of vertebrate genes. Gene sets as diverse as those expressed in avian skeletal muscle and in mammalian liver showed similar patterns of synonymous codon usage. There were no significant differences suggesting tissue-specific co-adaptation of codon usage patterns and tRNA anticodon profiles. The results indicate a consensus codon usage pattern for vertebrate genes which is largely independent of taxonomic class, tissue of expression, and the cellular fate and rate of evolution of the encoded proteins. Certain elements of the consensus codon usage pattern indicate that it is the product of natural selection and not simply a mutational equilibrium among phenotypically equivalent synonyms.
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  • 5
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    Journal of molecular evolution 35 (1992), S. 156-180 
    ISSN: 1432-1432
    Keywords: DNA damage ; DNA repair ; Chromatin ; Evolution ; Nucleosomes ; Nuclear matrix ; Active genes ; Z-DNA ; Sperm ; Mutation ; Molecular clock
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Some evolutionary consequences of different rates and trends in DNA damage and repair are explained. Different types of DNA damaging agents cause nonrandom lesions along the DNA. The type of DNA sequence motifs to be preferentially attacked depends upon the chemical or physical nature of the assaulting agent and the DNA base composition. Higher-order chromatin structure, the nonrandom nucleosome positioning along the DNA, the absence of nucleosomes from the promoter regions of active genes, curved DNA, the presence of sequence-specific binding proteins, and the torsional strain on the DNA induced by an increased transcriptional activity all are expected to affect rates of damage of individual genes. Furthermore, potential Z-DNA, H-DNA, slippage, and cruciform structures in the regulatory region of some genes or in other genomic loci induced by torsional strain on the DNA are more prone to modification by genotoxic agents. A specific actively transcribed gene may be preferentially damaged over nontranscribed genes only in specific cell types that maintain this gene in active chromatin fractions because of (1) its decondensed chromatin structure, (2) torsional strain in its DNA, (3) absence of nucleosomes from its regulatory region, and (4) altered nucleosome structure in its coding sequence due to the presence of modified histones and HMG proteins. The situation in this regard of germ cell lineages is, of course, the only one to intervene in evolution. Most lesions in DNA such as those caused by UV or DNA alkylating agents tend to diminish the GC content of genomes. Thus, DNA sequences not bound by selective constraints, such as pseudogenes, will show an increase in their AT content during evolution as evidenced by experimental observations. On the other hand, transcriptionally active parts may be repaired at rates higher than inactive parts of the genome, and proliferating cells may display higher repair activities than quiescent cells. This might arise from a tight coupling of the repair process with both transcription and replication, all these processes taking place on the nuclear matrix. Repair activities differ greatly among species, and there is a good correlation between life span and repair among mammals. It is predicted that genes that are transcriptionally active in germ-cell lineages have a lower mutation rate than bulk DNA, a circumstance that is expected to be reflected in evolution. Exception to this rule might be genes containing potential Z-DNA, H-DNA, or cruciform structures in their coding or regulatory regions that appear to be refractory to repair. This study supports the molecular clock hypothesis when applied to one gene within a group of related species and contends that evolutionary rates might vary between genes and gene segments not only as a result of differences in selective constraints but also as a result of differences in the rate of damage minus rate of repair among different segments of chromatin DNA.
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  • 6
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    Journal of molecular evolution 39 (1994), S. 448-451 
    ISSN: 1432-1432
    Keywords: Synonymous substitution ; Escherichia coli ; Salmonella typhimurium ; Mutation ; Recombination ; Selection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The spatial distribution of synonymous substitutions in enterobacterial genes is investigated. It is shown that synonymous substitutions are significantly clustered in such a way that a synonymous substitution in one codon elevates the rate of synonymous substitution in an adjacent codon by about 10%. The level of clustering does not appear to be related to the level of gene expression, and it is restricted to a range of two or three codons. There are at least three possible explanations: (1) sequence-directed mutagenesis, (2) recombination, and (3) selection.
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  • 7
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    Plant cell reports 13 (1994), S. 372-376 
    ISSN: 1432-203X
    Keywords: Asparagus officinalis L ; Habituation ; Mutation ; Somatic embryogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Somatic embryogenesis from different genotypes of Asparagus officinalis L. could be obtained by in vitro culture of shoot apices. Apices were first cultured on an auxin-rich inducing medium and then transferred onto a hormone-free development medium. All genotypes tested in this way produced a few somatic embryos. In some experiments, during the development phase, a new kind of friable highly embryogenic tissue appeared in a random manner. These tissues could be continuously subcultured on a hormone-free medium and were named embryogenic lines. Five of these embryogenic lines regenerated plants from somatic embryos. These regenerated plants exhibited an increased embryogenic response compared to the parent plants; e.g. apex culture produced somatic embryos without any auxin treatments. For one of the embryogenic lines, a genetic analysis showed that the improved embryogenic response of regenerated plants was controlled by a mendelian dominant monogenic mutation.
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  • 8
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    Current genetics 26 (1994), S. 281-284 
    ISSN: 1432-0983
    Keywords: Ofloxacin ; Mitochondria ; Mutation ; Recombination ; Topoisomerase ; Yeast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Ofloxacin, a specific inhibitor of bacterial topoisomerase II, is known to inhibit the growth of yeast cells and to induce rho − mutants in the yeast S. cerevisiae. The frequency of ofloxacin-induced petite mutants under non-growth conditions was found to be strongly diminished when the cells were depleted in intramitochondrial ATP. Under optimal conditions of mitochondrial mutagenesis the drug induced mitotic recombination and reverse mutation in diploid strains but failed to cure either killer plasmids or the 2 μm DNA of dividing cells. The sensitivity to ofloxacin of the strains deficient in the DNA strandbreak repair pathway (rad52) was significantly higher then that of the wild-type strains and of the mutants deficient in excision or mutagenic DNA repair. The results are compatible with the idea that the cytotoxic and genetic activity of ofloxacin in yeast probably results from the inhibited DNA ligation function of topoisomerase II creating DNA breaks that are reparable through the recombination repair pathway.
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  • 9
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    Environmental management 8 (1984), S. 309-324 
    ISSN: 1432-1009
    Keywords: Animals ; Indicators ; Air pollution ; Ecosystem responses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract With existing and proposed air-quality regulations, ecological disasters resulting from air emissions such as those observed at Copperhill, Tennessee, and Sudbury, Ontario, are unlikely. Current air-quality standards, however, may not protect ecosystems from subacute and chronic exposure to air emissions. The encouragement of the use of coal for energy production and the development of the fossil-fuel industries, including oil shales, tar sands, and coal liquification, point to an increase and spread of fossil-fuel emissions and the potential to influence a number of natural ecosystems. This paper reviews the reported responses of ecosystems to air-borne pollutants and discusses the use of animals as indicators of ecosystem responses to these pollutants. Animal species and populations can act as important indicators of biotic and abiotic responses of aquatic and terrestrial ecosystems. These responses can indicate long-term trends in ecosystem health and productivity, chemical cycling, genetics, and regulation. For short-term trends, fish and wildlife also serve as monitors of changes in community structure, signaling food-web contamination, as well as providing a measure of ecosystem vitality. Information is presented to show not only the importance of animals as indicators of ecosystem responses to air-quality degradation, but also their value as air-pollution indices, that is, as air-quality-related values (AQRV), required in current air-pollution regulation.
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  • 10
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    Current genetics 23 (1993), S. 430-434 
    ISSN: 1432-0983
    Keywords: S. cerevisiae ; Mutational homozygosis ; Loss of heterozygosity ; Mutation ; Recombination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A leucine-requiring hybrid of Saccharomyces cerevisiae, homoallelic at the LEU1 locus (leu1–12/leu1–12) and heterozygous for three chromosome-VII genetic markers distal to the LEU1 locus, was employed to inquire: (1) whether spontaneous gene mutation and mitotic segregation of heterozygous markers occur in positive nonrandom association and (2) whether homozygous LEU1/LEU1 mutant diploids are generated. The results demonstrate that gene mutation of leu1–12 to LEU1 and mitotic segregation of heterozygous chromosome-VII markers occur in strong positive nonrandom association, suggesting that the stimulatory DNA lesion is both mutagenic and recombinogenic. In addition, genetic analysis of diploid Leu+ revertants revealed that approximately 3% of mutations of leu1–12 to LEU1 result in LEU1/LEU1 homozygotes. Red-white sectored Leu+ colonies exhibit genotypes that implicate postreplicational chromatid breakage and exchange near the site of leu1–12 reversion, chromosome loss, and subsequent restitution of diploidy, in the sequence of events leading to mutational homozygosis. By analogy, diploid cell populations can yield variants homozygous for novel recessive gene mutations at biologically significant rates. Mutational homozygosis may be relevant to both carcinogenesis and the evolution of asexual diploid organisms.
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  • 11
    ISSN: 1432-0983
    Keywords: Thymidylate auxotrophy ; Mutation ; Recombination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A diploid yeast thymidylate auxotroph was grown under conditions of thymidylate stress ranging from depletion to excess levels of the nucleotide. High concentrations of thymidylate were mutagenic and recombinagenic whereas starvation for thymine nucleotides was recombinagenic and only slightly mutagenic. These results are discussed in relation to possible mutagenic and recombinagenic mechanisms of nucleotide pool imbalances.
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  • 12
    ISSN: 1432-072X
    Keywords: Fatty acids ; Mortierella alpina ; ω3-Desaturation ; Mutation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A mutant considered to be defective in the conversion of n-6 to n-3 fatty acids (ω3-desaturation) was derived from a Δ5-desaturation-defective mutant (Mut44) of Mortierella alpina 1S-4, after treating its spores with N-methyl-N′-nitro-N-nitrosoguanidine. This mutant cannot produce 8(Z),11(Z),14(Z),17(Z)-eicosatetraenoic acid or any other n-3 fatty acids, of which about 10% was found in its parental strain upon cultivation at 12°C. The mutant's growth rate was comparable to that of the parental strain when grown at 28°C, but it became much slower when the mutant grew at 12°C, at which the lag phase for Mut44 was about 2 d but 5 d for the mutant.
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  • 13
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    Archives of microbiology 124 (1980), S. 143-148 
    ISSN: 1432-072X
    Keywords: Anacystis ; Blue-green algae ; Cyanobacteria ; Mutation ; Pigments ; Red light ; Synecaococcus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Under far-red (〉650 nm) illumination Anacystis nidulans grows poorly and develops a low chlorophyll content. During continued culture over many generations there are increases in growth rate and in the chlorophyll/phycocyanin ratio, usually occurring in concomitant and stepwise fashion. From such selection cultures six clones have been established which differ from the parent in pigment content and show improved growth rate in far-red light. From the evidence at hand the six clones are presumed to be spontaneous mutants selected under the photosynthetically restrictive condition of far-red illumination.
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  • 14
    ISSN: 1432-072X
    Keywords: Temperature ; Mutation ; Thermotolerance ; Escherichia coli ; Salmonella typhimurium ; Pseudomonas aeruginosoa ; DNA gyrase ; gyrA ; Nalidixic acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A prolonged incubation of Escherichia, Salmonella or Pseudomonas at 48°C with nalidixic acid selected mutants (T48) able to grow at 48°C. A prolonged incubation at 54°C of the T48 mutants selected mutants (T54) able to grow at 54°C. These mutants were susceptible to the same bacteriophages as the original mesophilic strains. Auxotrophic phenotypes of Escherichia coli and Salmonella typhimurium mesophilic parents were demonstrated by these mutants if they were cultivated on minimal agar with cellobiose at 48°C or 54°C or on a minimal agar with glucose at 37°C. The T48 alleles mapped in the gyrA region of E. coli or S. typhimurium chromosome. In S. typhimurium the T54 alleles, which permit growth at 54°C, were shown by cotransductional analysis to be linked to gyrA.
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  • 15
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    Archives of microbiology 159 (1993), S. 98-100 
    ISSN: 1432-072X
    Keywords: Prophage induction ; Weigle reactivation ; Mutation ; Filamentation ; Nitrofurantoin ; Vibrio cholerae el tor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Treatment of Vibrio cholerae el tor strain SLH22(J) with nitrofurantoin induced dose-dependent prophage ‘kappa’, the maximum induction being 6-fold the spontaneous induction level. UV-inactivated ‘kappa’ phages were Weigle reactivated, the maximum Weigle factor being 1.8 and 2.0 respectively in nitrofurantoin and UV pretreated el tor strain H218 Smr. Nitrofurantoin treatment also caused significant filamentation of the el tor strain H218 Smr and mutation of these cells from ampicillin sensitivity to ampicillin resistance. The levels of the four SOS-like responses induced by this drug were low but significant.
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  • 16
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    Journal of mathematical biology 33 (1994), S. 111-137 
    ISSN: 1432-1416
    Keywords: B-cells ; Immune system ; Idiotypic networks ; Mutation ; Replicator equations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Abstract In order to evaluate the role of idiotypic networks in the operation of the immune system a number of mathematical models have been formulated. Here we examine a class of B-cell models in which cell proliferation is governed by a non-negative, unimodal, symmetric response function f(h), where the field h summarizes the effect of the network on a single clone. We show that by transforming into relative concentrations, the B-cell network equations can be brought into a form that closely resembles the replicator equation. We then show that when the total number of clones in a network is conserved, the dynamics of the network can be represented by the dynamics of a replicator equation. The number of equilibria and their stability are then characterized using methods developed for the study of second-order replicator equations. Analogies with standard Lotka-Volterra equations are also indicated. A particularly interesting result of our analysis is the fact that even though the immune network equations are not second-order, the number and stability of their equilibria can be obtained by a superposition of second-order replicator systems. As a consequence, the problem of finding all of the equilibrium points of the nonlinear network equations can be reduced to solving linear equations.
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  • 17
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    Journal of mathematical biology 30 (1992), S. 597-632 
    ISSN: 1432-1416
    Keywords: Autocatalysis ; Mutation ; Perturbation theory ; Qualitative analysis ; Replication dynamics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Abstract A class of kinetic equations describing catalysed and template induced replication, and mutation is introduced. This ODE in its most general form is split into two vector fields, a replication and a mutation field. The mutation field is considered as a perturbation of the replicator equation. The perturbation expansion is a Taylor series in a mutation parameter λ. First, second and higher order contributions are computed by means of the conventional Rayleigh-Schrödinger approach. Qualitative shifts in the positions of rest points and limit cycles on the boundary of the physically meaningful part of concentration space are predicted from flow topologies. The results of the topological analysis are summarized in two theorems which turned out to be useful in applications: the rest point migration theorem (RPM) and the limit cycle migration theorem (LCM). Quantitative expressions for the shifts of rest points are computed directly from the perturbation expansion. The concept is applied to a collection of selected examples from biophysical chemistry and biology.
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  • 18
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    The journal of membrane biology 139 (1994), S. 203-212 
    ISSN: 1432-1424
    Keywords: Mg2+ current ; Mutation ; Paramecium ; Intracellular Mg2+ homeostasis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract “Eccentric” is a newly-isolated mutant of Paramecium tetraurelia that fails to swim backwards in response to Mg2+. In the wild type, this backward swimming results from Mg2+ influx via a Mg2+-specific ion conductance (I Mg. Voltage-clamp analysis confirmed that, as suspected, step changes in membrane potential over a physiological range fail to elicit I Mg from eccentric. Further electrophysiological investigation revealed a number of additional ion-current defects in eccentric: (i) The Ca2+ current activated upon depolarization inactivates more slowly in eccentric than in the wild type, and it requires longer to recover from this inactivation. (ii) The Ca2+-dependent Na+ current deactivates significantly faster in the mutant, (iii) The two K+ currents observed upon hyperpolarization are reduced by 〉60% in eccentric. It is difficult to envision how these varied pleiotropic effects could result from loss of a single ion current. Rather, they suggest that the eccentric mutation affects a global regulatory system. Two plausible hypotheses are discussed.
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  • 19
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    Journal of mathematical biology 12 (1981), S. 355-362 
    ISSN: 1432-1416
    Keywords: Branching process ; Mutation ; Extinction ; Progeny size
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Abstract A branching process method is employed to study the survival probability of a slightly advantageous mutant gene with a general distribution of progeny size in a large population. A counter-example to a classic proposition is given. A somewhat weaker result is proved.
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  • 20
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    Journal of mathematical biology 30 (1992), S. 597-631 
    ISSN: 1432-1416
    Keywords: Autocatalysis ; Mutation ; Perturbation theory ; Qualitative analysis ; Replication dynamics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Abstract A class of kinetic equations describing catalysed and template induced replication, and mutation is introduced. This ODE in its most general form is split into two vector fields, a replication and a mutation field. The mutation field is considered as a perturbation of the replicator equation. The perturbation expansion is a Taylor series in a mutation parameter λ. First, second and higher order contributions are computed by means of the conventional Rayleigh-Schrödinger approach. Qualitative shifts in the positions of rest points and limit cycles on the boundary of the physically meaningful part of concentration space are predicted from flow topologies. The results of the topological analysis are summarized in two theorems which turned out to be useful in applications: the rest point migration theorem (RPM) and the limit cycle migration theorem (LCM). Quantitative expressions for the shifts of rest points are computed directly from the perturbation expansion. The concept is applied to a collection of selected examples from biophysical chemistry and biology.
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  • 21
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    Journal of mathematical biology 31 (1993), S. 123-132 
    ISSN: 1432-1416
    Keywords: Genealogy ; Coalescent ; Mutation ; Migration ; Markov chain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Abstract The genealogical process of neutral genes with mutation in geographically structured populations is investigated. Following Watterson [24], the sampled genes are partitioned into two types, old equivalence classes and new equivalence classes. The model is described by a bivariate continuous time Markov chain as an interactive particle system. Some results are obtained in the two-population model and the stepping stone model with symmetric nearest-neighbour migration.
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  • 22
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    Journal of mathematical biology 13 (1981), S. 95-104 
    ISSN: 1432-1416
    Keywords: Stochastic migration ; Island model ; Mutation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Abstract Recurrence relations are derived for stochastic migration in the island model with a finite number of subpopulations. Two models are considered, one involving a constant probability that each individual breeding in a given colony has migrated from another, the other assuming the exchange of fixed numbers of migrants between colonies each generation. The equilibrium solutions are expressed in terms of two measures of genetic differentiation among subpopulations, one similar to Nei's measure of genetic distance, and the other closely related to the coefficient of kinship. Both measures are shown to be necessary for a complete description of population structure. The predictions of the models of stochastic migration are compared with the corresponding classical model of deterministic migration.
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  • 23
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    Journal of mathematical biology 32 (1993), S. 33-44 
    ISSN: 1432-1416
    Keywords: Mutation ; Selection ; Random drift ; Muller's ratchet
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Abstract Two independently derived theories predict upper limits to the mutation rate beyond which evolution cannot be controlled by natural selection. One is the theory of Muller's ratchet, explaining the low phylogenetic age of parthenogenetic clones, the other one is the theory of error thresholds, predicting the maximal information content of selfreplicating molecules in prebiotic evolution. Both theories are based on similiar mathematical models but reach qualitatively different conclusions. Muller's ratchet only works in finite populations, while error thresholds are a deterministic phenomenon. In this paper it is shown that this discrepancy is due to different assumptions about the fitness values the selfreplicative units are allowed to assume. If no lower limit for the fitness values is assumed then the deterministic equilibrium frequency of the currently best genotype is strictly positive, no matter how strong mutation is, and random drift is required to cause its extinction (Muller's ratchet). On the other hand, positive lower limits for the fitness values lead to zero equilibrium frequencies in the deterministic description provided the mutation rate is high enough and no back mutations occur.
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  • 24
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    Journal of mathematical biology 32 (1994), S. 193-218 
    ISSN: 1432-1416
    Keywords: Selection ; Mutation ; Mutation load ; Quantitative genetic traits
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Abstract Haldane (1937) showed that the reduction of equilibrium mean fitness in an infinite population due to recurrent deleterious mutations depends only on the mutation rate but not on the harmfulness of mutants. His analysis, as well as more recent ones (cf. Crow 1970), ignored back mutation. The purpose of the present paper is to extend these results to arbitrary mutation patterns among alleles and to quantitative genetic traits. We derive first-order approximations for the equilibrium mean fitness (and the mutation load) and determine the order of the error term. For a metric trait under mutation-stabilizing-selection balance our result differs qualitatively from that of Crow and Kimura (1964), whose analysis is based on a Gaussian assumption. Our general approach also yields a mathematical proof that the variance under the usual mutation-stabilizing-selection model is, to first order, µ/s (the house-of-cards approximation) as µ/s tends to zero. This holds for arbitrary mutant distributions and does not require that the population mean coincide with the optimum. We show how the mutant distribution determines the order of the error term, and thus the accuracy of the house-of-cards approximation. Upper and lower bounds to the equilibrium variance are derived that deviate only to second order as µ/s tends to zero. The multilocus case is treated under the assumption of global linkage equilibrium.
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  • 25
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    Journal of mathematical biology 30 (1991), S. 199-213 
    ISSN: 1432-1416
    Keywords: Polygenic dynamics ; Quantitative trait ; Selection ; Mutation ; Cumulants ; Generating function
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Abstract A new approach for describing the evolution of polygenic traits subject to selection and mutation is presented. Differential equations for the change of cumulants of the allelic frequency distribution at a particular locus and for the cumulants of the distributions of genotypic and phenotypic values are derived. The derivation is based on the assumptions of random mating, no sex differences, absence of random drift, additive gene action, linkage equilibrium, and Hardy-Weinberg proportions. Cumulants are a set of parameters that, like moments, describe the shape of a probability density. Compared with moments, however, they have properties that make them a much more convenient tool for investigating polygenic traits. Applications to directional and stabilizing selection are given.
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  • 26
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    Theoretical and applied genetics 65 (1983), S. 41-46 
    ISSN: 1432-2242
    Keywords: Triticum aestivum ; Wheat ; Protein ; Mutation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Poor adaptability or functional quality of much germplasm used for breeding high-protein hard red winter wheats prompted mutagenesis as an alternative means of increasing grain protein content. Four hard red winter wheat genotypes — KS644 (‘Triumph// Concho/Triumph’), ‘Kaw’, ‘Parker’, and ‘Shawnee’ — were treated with 0.40 M ethyl methanesulfonate (EMS). Advanced lines (M8-M10) were selected that had a 3-year mean grain protein advantage of 0.7% to 2.0% over controls. Increased grain protein content was generally associated with decreased grain yield and kernel weight, but some high-protein mutant lines had yields or kernel weights similar to those of original genotypes. Changes in height and lodging induced by EMS were generally favorable, most mutants being shorter and lodging less than controls, but blooming date was generally delayed, a deleterious change. One line also changed from resistant to segregating for wheat soil-borne mosaic virus. Mutant lines might be utilized in cross-breeding programs, particularly if negative pleiotropic effects and linkages are absent.
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  • 27
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    Theoretical and applied genetics 65 (1983), S. 225-230 
    ISSN: 1432-2242
    Keywords: Tissue culture ; Mutation ; Sequential mutations ; Rice ; Oryza sativa L.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Four mutations for early heading, albina, short culm and sterility were obtained in the progenies of twelve rice plants regenerated from a single callus of a rice seed. Studies on the segregation rates of these mutations revealed that for each mutation a single recessive gene was likely to be involved and that there was no linkage among the genes. The segregation pattern also showed that these mutations were induced in the following sequence: early heading, albina, and short culm and sterility during the stage of callus growth until the beginning of the regeneration of the rice plants.
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  • 28
    ISSN: 1432-2242
    Keywords: Mutation ; Normalizing-selection ; Lethal-equivalence ; Genetic-load ; Neutral-theory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Through a series of genetic load studies made on 1) samples of Drosophila willistoni from two sites in Mesitas, Colombia, it was found that the relative contributions to the total, subvital and lethal loads reflect lethal equivalences (B/A) ratios which support more the balancing theory of population structure than the neutralist theory. Moreover, measurements of population size have revealed the existance of very small demes in local populations. Under such conditions we have calculated extremely small lethal equivalence ratios in demes where probably a great deal of consanguinity takes place. We are aware that under these conditions B/A ratios cannot be very good monitors of random load measurements and, therefore, suggest a change in the mathematical formulation that take into consideration the existance of small populations. Furthermore, it appears plausible that the degree of penetrance in the heterozygous condition changes as the population structure changes. We speculate that natural populations may have unknown selective mechanisms capable of guiding unknown dominance modifiers according to the intensity of selection.
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  • 29
    ISSN: 1432-2242
    Keywords: Interchange ; Chromosome polymorphism ; Mutation ; Selection ; Equilibrium ; Rye
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A persistent chromosomal polymorphism exists in a population of cultivated rye, Secale cereale (Candela et al. 1979). In order to ascertain the possible causes that maintain it, we have estimated the fitness values of structurally homozygous and heterozygous plants and the mutation rate of spontaneous interchange. The estimates of the selection coefficient against heterozygotes (s=0.15-0.40) and of the mutation rate u=6.12×10−2 support a mutation-selection equilibrium as a likely cause of the interchange chromosome polymorphism.
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  • 30
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    Theoretical and applied genetics 67 (1984), S. 203-205 
    ISSN: 1432-2242
    Keywords: Ethyl methanesulphonate ; Mutation ; Myo-inositol ; Nicotiana tabacum, tobacco
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Tobacco seeds treated with ethyl methanesulphonate produces mutations as well as physiological growth debility. The addition of myo-inositol to seeds undergoing mutagenic treatment stimulated growth and increased survival of subsequent plants with negligible effect on the mutation frequency.
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  • 31
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    Theoretical and applied genetics 87 (1994), S. 657-667 
    ISSN: 1432-2242
    Keywords: Transposable elements ; Mutation ; Evolution ; DNA repair ; Gene conversion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The mobile DNAs of the Mutator system of maize (Zea mays) are exceptional both in structure and diversity. So far, six subfamilies of Mu elements have been discovered; all Mu elements share highly conserved terminal inverted repeats (TIRs), but each sub-family is defined by internal sequences that are apparently unrelated to the internal sequences of any other Mu subfamily. The Mu1/Mu2 subfamily of elements was created by the acquisition of a portion of a standard maize gene (termed MRS-A) within two Mu TIRs. Beside the unusually long (185–359 bp) and diverse TIRs found on all of these elements, other direct and inverted repeats are often found either within the central portion of a Mu element or within a TIR. Our computer analyses have shown that sequence duplications (mostly short direct repeats interrupted by a few base pairs) are common in non-autonomous members of the Mutator, Ac/Ds, and Spm(En) systems. These duplications are often tightly associated with the element-internal end of the TIRs. Comparisons of Mu element sequences have indicated that they share more terminal components than previously reported; all subfamilies have at least the most terminal 215 bp, at one end or the other, of the 359-bp Mu5 TIR. These data suggest that many Mu element subfamilies were generated from a parental element that had termini like those of Mu5. With the Mu5 TIRs as a standard, it was possible to determine that elements like Mu4 could have had their unusual TIRs created through a three-step process involving (1) addition of sequences to interrupt one TIR, (2) formation of a stem-loop structure by one strand of the element, and (3) a subsequent DNA repair/gene conversion event that duplicated the insertion(s) within the other TIR. A similar repair/conversion extending from a TIR stem into loop DNA could explain the additional inverted repeat sequences added to the internal ends of the Mu4 and Mu7 TIRs. This same basic mechanism was found to be capable of generating new Mu element subfamilies. After endonucleolytic attack of the loop within the stem-loop structure, repair/conversion of the gap could occur as an intermolecular event to generate novel internal sequences and, therefore, a new Mu element subfamily. Evidence supporting and expanding this model of new Mu element subfamily creation was identified in the sequence of MRS-A.
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  • 32
    ISSN: 1617-4623
    Keywords: Rice ; Tetraploid irradiation ; Genome rearrangement ; rDNA ; Mutation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The organization of tandemly repeated sequences of ribosomal DNA (rDNA) in rice mutants derived from γ-irradiated tetraploids was analyzed. Southern hybridization analysis of nuclear DNA revealed that most of the intergenic spacers (IGSs) in mutant rDNA are replaced concertedly by new molecular species. The new IGSs are produced by the amplification of a subrepeat of about 250 bp. Results obtained from sequence analyses indicate that various intermediate molecular species of the subrepeat were formed during structuring of the IGS region and that many rearrangements occurred between them. These findings demonstrate the effectiveness of recurrent irradiation of tetraploids for inducing artificial genome rearrangement, and also indicate the extreme plasticity and variability of genome structure in plants.
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  • 33
    ISSN: 1617-4623
    Keywords: TOL plasmid ; Biodegradation ; Pseudornonas putida ; Evolution ; Mutation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract TOL plasmid pWW0 from Pseudomonas putida mt-2 encodes catabolic enzymes required for the oxidation of toluene and xylenes. The structural genes for these catabolic enzymes are clustered into two operons, the xylCMABN operon, which encodes a set of enzymes required for the transformation of toluene/xylenes to benzoate/toluates, and the xylXYZLTEGFJQKIH operon, which encodes a set of enzymes required for the transformation of benzoate/toluates to Krebs cycle intermediates. The latter operon can be divided physically and functionally into two parts, the xylXYZL cluster, which is involved in the transformation of benzoate/toluates to (methyl)catechols, and the xylTEGFJQKIH cluster, which is involved in the transformation of (methyl)catechols to Krebs cycle intermediates. Genes isofunctional to xylXYZL are present in Acinetobacter calcoaceticus, and constitute a benzoate-degradative pathway, while xylTEGFJQKIH homologous encoding enzymes of a methylphenol-degradative pathway and a naphthalene-degradative pathway are present on plasmid pVI150 from P. putida CF600, and on plasmid NAH7 from P. putida PpG7, respectively. Comparison of the nucleotide sequences of the xylXYZLTEGFJQKIH genes with other isofunctional genes suggested that the xylTEGFJQKIH genes on the TOL plasmid diverged from these homologues 20 to 50 million years ago, while the xylXYZL genes diverged from the A. calcoaceticus homologues 100 to 200 million years ago. In codons where amino acids are not conserved, the substitution rate in the third base was higher than that in synonymous codons. This result was interpreted as indicating that both single and multiple nucleotide substitutions contributed to the amino acid-substituting mutations, and hence to enzyme evolution. This observation seems to be general because mammalian globin genes exhibit the same tendency.
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  • 34
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    Pharmacy world & science 16 (1994), S. 55-61 
    ISSN: 1573-739X
    Keywords: AMP deaminase/deliciency ; Deficiency diseases ; Genetics, biochemical ; Mutation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract In man, there are at least four isoforms of adenosine monophosphate deaminase (AMPD): myoadenylate deaminase in skeletal muscle, the L isoform in liver, and the E1 and E2 isoforms in erythrocytes. Myoadenylafe deaminase is encoded by the AMPD1 gene located on chromosome 1 p13-p21, the L isoform by the AMPD2 gene, and both isoforms in erythrocytes by the AMPD3 gene. Myoadenylate deaminase deficiency is found in 2–3% of all muscle biopsies. The inborn type of myoadenylate deaminase deficiency is caused by a single mutant allele harbouring two mutations: C34→T (Gin→Stop) and C143→T (Pro-48→Leu). Population studies revealed a frequency of the mutant allele of 0.12 in Caucasian Americans and Germans. The C34→T mutation is located in exon 2, which is alternatively spliced in part of the AMPD1 transcript in human muscle. Since the second mutation does not affect enzyme function, alternatively spliced mRNA encodes a catalytically active enzyme. Only one patient with a disorder linked to liver AMPD has been described so far. In this patient the decreased inhibition of this enzyme by GTP resulted in uric acid overproduction and gout. A complete lack of erythrocyte AMPD activity is found in asymptomatic subjects. The molecular basis of both disorders is not yet known.
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  • 35
    ISSN: 1617-4623
    Keywords: Retroposon ; Transposable element ; Mutation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We analysed the structure of the white locus of Drosophila melanogaster in a family of related white mutants. The white-one mutant has bleach white eyes, and a Doc transposable element is inserted into the promoter region of the white locus. The DNA sequence of this Doc insertion was determined, and showed it to be closely related to other Drosophila melanogaster retroposons such as the I factor and the F, G and jockey elements. There are two long open reading frames, which encode a putative nucleic acid binding protein and a putative reverse transcriptase, respectively. Two independent, partially pigmented derivatives were analysed by cloning sequences from this region. In white-honey a transposable element of the retroviral class, B104, is inserted within the Doe element. In white-eosin there is an insertion within the Doc element of a 190 by sequence that appears to be a member of a novel family of transposable elements. This pogo element is of the same structural class as the Drosophila melanogaster P and hobo elements. These data are consistent with the hypothesis that the Doc retroposon cannot excise, and that, for the white-one mutation, flies with altered phenotypes are most often generated by the insertion of additional transposable elements.
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  • 36
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    Molecular genetics and genomics 244 (1994), S. 295-302 
    ISSN: 1617-4623
    Keywords: DNA repair ; Recombination ; Virulence ; Mutation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The recA + gene of Vibrio cholerae O1 has been cloned, its nucleotide sequence determined and the product characterized. A deletion mutation was constructed in the recA gene and mutants showed the typical sensitivity to UV and to DNA-damaging agents, as well as an inability to mediate homologous DNA recombination. The chromosomal recA deletion mutants in V. cholerae do not show altered virulence in the infant mouse cholera model and are thus ideal strains for use in complementation studies.
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  • 37
    ISSN: 1617-4623
    Keywords: Streptococcus pyogenes ; vir regulon ; emm-related genes ; Recombination ; Mutation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract One of the most prevalent genetic lineages of group A streptococci (GAS) harbors a genomic locus termed the large vir regulon, which contains an emm gene encoding the antiphagocytic M protein, and structurally related fcrA and enn (emm-related) genes encoding immunoglobulin-binding proteins. In the present study more than 100 large vir regulons from 42 different GAS serotypes were analyzed by PCR and partial DNA sequencing. On comparing these data to published sequences, sites of mutational and putative recombinational events were identified and ordered with respect to their intra/intergenic or intra/intergenomic nature. The emm-related genes were found to display small intragenic deletions or insertions, were completely deleted from, or newly inserted into the genome, or were fused to adjacent genes. Intergenomic exchanges of complete emm-related genes, or segments thereof, between different vir regulons were detected. Most of these processes seem to involve short flanking direct repeats. Occasionally, the structural changes could be correlated with changes in the functions of the encoded proteins.
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  • 38
    ISSN: 1617-4623
    Keywords: Deficiency mapping ; Mutation ; Telomere Chromosome structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A mutator, mu2, in Drosophila melanogaster has been identified recently that potentiates the recovery of terminal deficiencies. The deleted chromosomes behave as if they had been capped; that is, they are protected from degradation and from fusion with other chromosome fragments. The mutator maps near the telomere on the left arm of chromosome 3. Using the selectable marker Aprt, 150 deficiencies for region 62 of the cytological map have been recovered. These deficiencies identify the map position of mu2 as 62B11-C1. A yeast artificial chromosome spanning this region has been subcloned into lambda phage, and the positions of deficiency breakpoints on either side of the mu2 gene have been identified within the subclones. These positions limit the location of the left end of the gene to a 23 kb region. In the course of these experiments, three additional, presumptive mutant alleles were identified, suggesting that other mutator alleles remain undiscovered in many standard laboratory stocks.
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  • 39
    ISSN: 1617-4623
    Keywords: Hordeum vulgare L. ; Nitrite reduction ; Mutation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Eleven green individuals were isolated when 95000 M2 plants of barley (Hordeum vulgare L.), mutagenised with azide in the M1, were screened for nitrite accumulation in their leaves after nitrate treatment in the light. The selected plants were maintained in aerated liquid culture solution containing glutamine as sole nitrogen source. Not all plants survived to flowering and some others that did were not fertile. One of the selected plants, STA3999, from the cultivar Tweed could be crossed to the wild-type cultivar and analysis of the F2 progeny showed that leaf nitrite accumulation was due to a recessive mutation in a single nuclear gene, which has been designated Nir1. The homozygous nir1 mutant could be maintained to flowering in liquid culture with either glutamine or ammonium as sole nitrogen source, but died within 14 days after transfer to compost. The nitrite reductase cross-reacting material seen in nitrate-treated wild-type plants could not be detected in either the leaf or the root of the homozygous nir1 mutant. Nitrite reductase activity, measured with dithionite-reduced methyl viologen as electron donor, of the nitrate-treated homozygous nir1 mutant was much reduced but NADH-nitrate reductase activity was elevated compared to wild-type plants. We conclude that the Nir1 locus determines the formation of nitrite reductase apoprotein in both the leaf and root of barley and speculate that it represents either the nitrite reductase apoprotein gene locus or, less likely, a regulatory locus whose product is required for the synthesis of nitrite reductase, but not nitrate reductase. Elevation of NADH-nitrate reductase activity in the nir1 mutant suggests a regulatory perturbation in the expression of the Narl gene.
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  • 40
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    Plant and soil 82 (1984), S. 427-438 
    ISSN: 1573-5036
    Keywords: Mutant ; Mutation ; Nitrate ; Nitrate reductase ; Nodulation ; Pisum sativum L. ; Rhizobium leguminosarum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary In pea (Pisum sativum L.), mutants could be induced, modified in the symbiotic interaction withRhizobium leguminosarum. Among 250 M2-families, two nodulation resistant mutants (K5 and K9) were obtained. In mutant K5 the nodulation resistance was monogenic recessive and not Rhizobium strain specific. Out of 220 M2-families one mutant nod3 was found which could form nodules at high nitrate concentrations (15 mM KNO3). This mutant nodulated abundantly with severalRhizobium strains, both in the absence and presence of nitrate. Probably as the result of a pleiotropic effect, its root morphology was also changed. Among 1800 M2-families, five nitrate reductase deficient mutants were obtained and one of them (mutant E1) was used to study the inhibitory effect of nitrate on nodulation and nitrogen fixation. The results of the present investigation show that pea mutants which are modified in their symbiosis withRhizobium leguminosarum, can readily be obtained. The significance of such mutants for fundamental studies of the legume-Rhizobium symbiosis and for applications in plant breeding is discussed.
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  • 41
    Publication Date: 1994-02-25
    Description: Activation of the serine-threonine kinase p34cdc2 at an inappropriate time during the cell cycle leads to cell death that resembles apoptosis. Premature activation of p34cdc2 was shown to be required for apoptosis induced by a lymphocyte granule protease. The kinase was rapidly activated and tyrosine dephosphorylated at the initiation of apoptosis. DNA fragmentation and nuclear collapse could be prevented by blocking p34cdc2 activity with excess peptide substrate, or by inactivating p34cdc2 in a temperature-sensitive mutant. Premature p34cdc2 activation may be a general mechanism by which cells induced to undergo apoptosis initiate the disruption of the nucleus.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Shi, L -- Nishioka, W K -- Th'ng, J -- Bradbury, E M -- Litchfield, D W -- Greenberg, A H -- New York, N.Y. -- Science. 1994 Feb 25;263(5150):1143-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Manitoba Institute of Cell Biology, University of Manitoba, Winnipeg, Canada.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8108732" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; *Apoptosis ; CDC2 Protein Kinase/*metabolism ; DNA Damage ; Deoxyribonucleases/pharmacology ; Enzyme Activation ; Enzyme Induction ; Membrane Glycoproteins/pharmacology ; Mice ; Mitosis ; Molecular Sequence Data ; Perforin ; Phosphorylation ; Pore Forming Cytotoxic Proteins ; Serine Endopeptidases/pharmacology ; Tumor Cells, Cultured
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  • 42
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-01-26
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Marx, J -- New York, N.Y. -- Science. 1990 Jan 26;247(4941):408-10.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2405484" target="_blank"〉PubMed〈/a〉
    Keywords: Alzheimer Disease/*drug therapy/metabolism ; Amyloid/metabolism ; Amyloid beta-Peptides ; Animals ; Clinical Trials as Topic ; Humans ; Nerve Growth Factors/adverse effects/*therapeutic use ; Recombinant Proteins
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  • 43
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-03-30
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉New York, N.Y. -- Science. 1990 Mar 30;247(4950):1539.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/11642762" target="_blank"〉PubMed〈/a〉
    Keywords: *Animal Experimentation ; *Animal Welfare ; Animals ; Humans ; Literature ; *Primates ; *Statistics as Topic ; Substance-Related Disorders ; United States
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  • 44
    Publication Date: 1990-08-10
    Description: The stimulation of phospholipase A2 by thrombin and type 2 (P2)-purinergic receptor agonists in Chinese hamster ovary cells is mediated by the G protein Gi. To delineate alpha chain regulatory regions responsible for control of phospholipase A2, chimeric cDNAs were constructed in which different lengths of the alpha subunit of Gs (alpha s) were replaced with the corresponding sequence of the Gi alpha subunit (alpha i2). When a carboxyl-terminal chimera alpha s-i(38), which has the last 38 amino acids of alpha s substituted with the last 36 residues of alpha i2, was expressed in Chinese hamster ovary cells, the receptor-stimulated phospholipase A2 activity was inhibited, although the chimera could still activate adenylyl cyclase. Thus, alpha s-i(38) is an active alpha s, but also a dominant negative alpha i molecule, indicating that the last 36 amino acids of alpha i2 are a critical domain for G protein regulation of phospholipase A2 activity.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Gupta, S K -- Diez, E -- Heasley, L E -- Osawa, S -- Johnson, G L -- DK37871/DK/NIDDK NIH HHS/ -- GM30324/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1990 Aug 10;249(4969):662-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Division of Basic Sciences, National Jewish Center for Immunology and Respiratory Medicine, Denver, CO 80206.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2166341" target="_blank"〉PubMed〈/a〉
    Keywords: Adenosine Triphosphate/pharmacology ; Animals ; Arachidonic Acid ; Arachidonic Acids/metabolism ; Cell Line ; Chlorides/pharmacology ; Enzyme Activation ; GTP-Binding Proteins/*genetics/metabolism ; Inositol Phosphates/metabolism ; Kinetics ; Lithium/pharmacology ; Lithium Chloride ; Macromolecular Substances ; *Mutation ; Phospholipases/*metabolism ; Phospholipases A/*metabolism ; Phospholipases A2 ; Receptors, Purinergic/drug effects/*physiology ; Restriction Mapping ; Thrombin/antagonists & inhibitors/*pharmacology ; Transfection
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  • 45
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-02-02
    Description: The RNA moiety of the ribonucleoprotein enzyme telomerase from the ciliate Euplotes crassus was identified and its gene was sequenced. Functional analysis, in which oligonucleotides complementary to portions of the telomerase RNA were tested for their ability to prime telomerase in vitro, showed that the sequence 5' CAAAACCCCAAA 3' in this RNA is the template for synthesis of telomeric TTTTGGGG repeats by the Euplotes telomerase. The data provide a direct demonstration of a template function for a telomerase RNA and demarcate the outer boundaries of the telomeric template. Telomerase can now be defined as a specialized reverse transcriptase.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Shippen-Lentz, D -- Blackburn, E H -- New York, N.Y. -- Science. 1990 Feb 2;247(4942):546-52.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular and Cell Biology, University of California, Berkeley 94720.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1689074" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Base Sequence ; Ciliophora/enzymology/*genetics ; DNA Nucleotidylexotransferase/*genetics ; Genes ; Molecular Sequence Data ; Oligonucleotide Probes ; RNA/*genetics ; Sequence Homology, Nucleic Acid ; *Templates, Genetic
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  • 46
    Publication Date: 1990-06-29
    Description: In Rous sarcoma virus (RSV)-infected chickens, wounding leads to tumor formation with nearly 100% frequency in tissues that would otherwise remain tumor-free. Identifying molecular mediators of this phenomenon should yield important clues to the mechanisms involved in RSV tumorigenesis. Immunohistochemical staining showed that TGF-beta is present locally shortly after wounding, but not unwounded controls. In addition, subcutaneous administration of recombinant transforming growth factor-beta 1 (TGF-beta 1) could substitute completely for wounding in tumor induction. A treatment protocol of four doses of 800 nanograms of TGF-beta resulted in v-src-expressing tumors with 100% frequency; four doses of only 10 nanograms still led to tumor formation in 80% of the animals. This effect was specific, as other growth factors with suggested roles in wound healing did not elicit the same response. Epidermal growth factor (EGF) or TGF-alpha had no effect, and platelet-derived growth factor (PDGF) or insulin-like growth factor-1 (IGF-1) yielded only occasional tumors after longer latency. TGF-beta release during the wound-healing response may thus be a critical event that creates a conducive environment for RSV tumorigenesis and may act as a cofactor for transformation in this system.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sieweke, M H -- Thompson, N L -- Sporn, M B -- Bissell, M J -- New York, N.Y. -- Science. 1990 Jun 29;248(4963):1656-60.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Cell and Molecular Biology Division, Lawrence Berkeley Laboratory, University of California, Berkeley 94720.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2163544" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Antibodies ; Chickens ; Epidermal Growth Factor/pharmacology ; Humans ; Immunoenzyme Techniques ; Insulin-Like Growth Factor I/pharmacology ; Platelet-Derived Growth Factor/pharmacology ; Recombinant Proteins/pharmacology ; Sarcoma, Avian/complications/*pathology ; Swine ; Transforming Growth Factors/analysis/*pharmacology ; Wound Healing ; Wounds and Injuries/complications/*pathology
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    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 47
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-04-06
    Description: The rate of release of guanine nucleotides from the ras proteins (Ras) is extremely slow in the presence of Mg2+. It seemed likely, therefore that a factor might exist to accelerate the release of guanosine diphosphate (GDP), and hence the exchange of GDP for guanosine triphosphate (GTP). Such a factor has now been discovered in rat brain cytosol. Brain cytosol was found to catalyze, by orders of magnitude, the release of guanine nucleotides from recombinant v-H-Ras protein bound with [alpha-32P]GDP. This effect occurred even in the presence of a large excess of Mg2+, but was destroyed by heat or by incubation of the cytosol for an hour at 37 degrees C in the absence of phosphatase inhibitors. The effect was observed with either v-H-Ras or c-H-Ras, but not with p25rab3A, a small G protein with about 30% similarity to Ras. The effect could not be mimicked by addition of recombinant Ras-GAP or purified GEF, a guanine nucleotide exchange factor involved in the regulation of eukaryotic protein synthesis. By gel filtration chromatography, the factor appears to possess a molecular size between 100,000 and 160,000 daltons. This protein (Ras-guanine nucleotide-releasing factor, or Ras-GRF) may be involved in the activation of p21ras.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wolfman, A -- Macara, I G -- CA 43551/CA/NCI NIH HHS/ -- ES 01247/ES/NIEHS NIH HHS/ -- GM 41220/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1990 Apr 6;248(4951):67-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biophysics, University of Rochester Medical Center, NY 14642.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2181667" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Binding, Competitive ; Brain/metabolism ; Cholic Acids ; Cytosol/*metabolism ; Guanine Nucleotides/*metabolism ; Guanosine 5'-O-(3-Thiotriphosphate) ; Guanosine Diphosphate/*metabolism ; Guanosine Triphosphate/analogs & derivatives/metabolism ; Hot Temperature ; Immunosorbent Techniques ; Kinetics ; Magnesium Chloride/pharmacology ; Molecular Weight ; Proto-Oncogene Proteins/*metabolism ; Proto-Oncogene Proteins p21(ras) ; Rats ; Thionucleotides/metabolism
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  • 48
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-09-14
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Skerrett, P J -- New York, N.Y. -- Science. 1990 Sep 14;249(4974):1248.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2119053" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Diabetes Mellitus, Experimental/*surgery ; Graft Enhancement, Immunologic ; Immune Tolerance ; *Islets of Langerhans Transplantation ; Rats ; T-Lymphocytes/immunology ; Thymus Gland/surgery ; Transplantation, Heterotopic
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  • 49
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-05-11
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wright, K -- New York, N.Y. -- Science. 1990 May 11;248(4956):682-3.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2333519" target="_blank"〉PubMed〈/a〉
    Keywords: Acquired Immunodeficiency Syndrome/*microbiology ; Animals ; HIV/isolation & purification/pathogenicity ; Humans ; Liver/microbiology ; Mycoplasma/*isolation & purification/pathogenicity ; National Institutes of Health (U.S.) ; Research/standards ; Research Design ; United States
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  • 50
    Publication Date: 1990-09-21
    Description: Leukocytes respond to lipopolysaccharide (LPS) at nanogram per milliliter concentrations with secretion of cytokines such as tumor necrosis factor-alpha (TNF-alpha). Excess secretion of TNF-alpha causes endotoxic shock, an often fatal complication of infection. LPS in the bloodstream rapidly binds to the serum protein, lipopolysaccharide binding protein (LBP), and cellular responses to physiological levels of LPS are dependent on LBP. CD14, a differentiation antigen of monocytes, was found to bind complexes of LPS and LBP, and blockade of CD14 with monoclonal antibodies prevented synthesis of TNF-alpha by whole blood incubated with LPS. Thus, LPS may induce responses by interacting with a soluble binding protein in serum that then binds the cell surface protein CD14.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wright, S D -- Ramos, R A -- Tobias, P S -- Ulevitch, R J -- Mathison, J C -- AI 15136/AI/NIAID NIH HHS/ -- AI 22003/AI/NIAID NIH HHS/ -- AI 24775/AI/NIAID NIH HHS/ -- New York, N.Y. -- Science. 1990 Sep 21;249(4975):1431-3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Cellular Physiology and Immunology, Rockefeller University, New York, NY 10021.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1698311" target="_blank"〉PubMed〈/a〉
    Keywords: *Acute-Phase Proteins ; Animals ; Antibodies, Monoclonal/immunology ; Antigens, CD/*immunology ; Antigens, CD14 ; Antigens, CD18 ; Antigens, Differentiation, Myelomonocytic/*immunology ; Carrier Proteins/*immunology ; Erythrocytes/immunology ; Leukocytes/immunology ; Lipopolysaccharides/*immunology ; Macrophages/immunology ; *Membrane Glycoproteins ; Receptors, Leukocyte-Adhesion/immunology ; Sheep ; Tumor Necrosis Factor-alpha/biosynthesis
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  • 51
    Publication Date: 1990-06-01
    Description: Better understanding of the pathogenesis of acquired immunodeficiency syndrome (AIDS) would be greatly facilitated by a relevant animal model that uses molecularly cloned virus of defined sequence to induce the disease. Such a system would also be of great value for AIDS vaccine research. An infectious molecular clone of simian immunodeficiency virus (SIV) was identified that induces AIDS in common rhesus monkeys in a time frame suitable for laboratory investigation. These results provide another strong link in the chain of evidence for the viral etiology of AIDS. More importantly, they define a system for molecular dissection of the determinants of AIDS pathogenesis.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kestler, H -- Kodama, T -- Ringler, D -- Marthas, M -- Pedersen, N -- Lackner, A -- Regier, D -- Sehgal, P -- Daniel, M -- King, N -- AI25328/AI/NIAID NIH HHS/ -- RR00168/RR/NCRR NIH HHS/ -- RR00169/RR/NCRR NIH HHS/ -- etc. -- New York, N.Y. -- Science. 1990 Jun 1;248(4959):1109-12.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉New England Regional Primate Research Center, Harvard Medical School, Southborough, MA 01772.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2160735" target="_blank"〉PubMed〈/a〉
    Keywords: *Acquired Immunodeficiency Syndrome ; Animals ; Antibodies, Viral/biosynthesis ; Cloning, Molecular ; *Disease Models, Animal ; Leukocytes, Mononuclear/microbiology ; Macaca mulatta ; Macrophages/microbiology ; Opportunistic Infections/etiology ; *Retroviridae Infections/complications/immunology ; *Simian Immunodeficiency Virus/genetics/immunology/isolation & ; purification/pathogenicity ; Transfection ; Virus Replication
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  • 52
    Publication Date: 1990-02-09
    Description: The control of cellular senescence by specific human chromosomes was examined in interspecies cell hybrids between diploid human fibroblasts and an immortal, Syrian hamster cell line. Most such hybrids exhibited a limited life span comparable to that of the human fibroblasts, indicating that cellular senescence is dominant in these hybrids. Karyotypic analyses of the hybrid clones that did not senesce revealed that all these clones had lost both copies of human chromosome 1, whereas all other human chromosomes were observed in at least some of the immortal hybrids. The application of selective pressure for retention of human chromosome 1 to the cell hybrids resulted in an increased percentage of hybrids that senesced. Further, the introduction of a single copy of human chromosome 1 to the hamster cells by microcell fusion caused typical signs of cellular senescence. Transfer of chromosome 11 had no effect on the growth of the cells. These findings indicate that human chromosome 1 may participate in the control of cellular senescence and further support a genetic basis for cellular senescence.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sugawara, O -- Oshimura, M -- Koi, M -- Annab, L A -- Barrett, J C -- New York, N.Y. -- Science. 1990 Feb 9;247(4943):707-10.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2300822" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cell Line ; Cell Survival/*genetics ; Chromosome Mapping ; *Chromosomes, Human, Pair 1 ; Clone Cells ; Cricetinae ; Diploidy ; Fibroblasts/*cytology ; Humans ; Hybrid Cells/*cytology ; Hypoxanthine Phosphoribosyltransferase/genetics ; Karyotyping ; Mice ; Ploidies ; Transfection ; Translocation, Genetic ; X Chromosome
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  • 53
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-08-03
    Description: Eukaryotic cells respond to elevated temperatures by rapidly activating the expression of heat shock genes. Central to this activation is heat shock-inducible binding of the transcriptional activator, termed heat shock factor (HSF), to common regulatory elements, which are located upstream of all heat shock genes. The DNA binding activity of the inactive form of Drosophila HSF was induced in vitro by treatment with polyclonal antibodies to the purified, in vivo-activated factor. This finding, together with observations that high temperature and low pH activate HSF binding in vitro, suggests that the inactive form of HSF can directly recognize and transduce the heat shock signal without undergoing a covalent modification of protein structure.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Zimarino, V -- Wilson, S -- Wu, C -- New York, N.Y. -- Science. 1990 Aug 3;249(4968):546-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Biochemistry, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2200124" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Antibodies ; Drosophila/*genetics ; *Gene Expression Regulation ; HeLa Cells/metabolism ; Heat-Shock Proteins/*genetics/immunology/isolation & purification/metabolism ; Humans ; Saccharomyces cerevisiae/genetics ; Transcription Factors/*metabolism ; *Transcription, Genetic
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  • 54
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-06-15
    Description: The specificity of mature CD8+ and CD4+ T lymphocytes is controlled by major histocompatibility complex (MHC) class I and class II molecules, respectively. The MHC class specificity of T cells is stringent in many assays, but is less evident when cells are supplemented with exogenous lymphokines. The repertoire of T cells is shaped through contact with MHC molecules in the thymus and involves a complex process of positive selection and negative selection (tolerance). Tolerance of immature T cells to MHC molecules can reflect either clonal deletion or anergy and results from intrathymic contact with several cell types, including epithelial cells and cells with antigen-presenting function. Unlike immature T cells, mature T cells are relatively resistant to tolerance induction. In certain situations partial unresponsiveness of mature T cells can be achieved by exposing T cells to foreign MHC molecules expressed on atypical antigen-presenting cells. Tolerance is rarely complete, however, and the precise requirements for tolerizing mature T cells are still unclear.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sprent, J -- Gao, E K -- Webb, S R -- AI21487/AI/NIAID NIH HHS/ -- CA25803/CA/NCI NIH HHS/ -- CA38355/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 1990 Jun 15;248(4961):1357-63.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Immunology, Research Institute of Scripps Clinic, La Jolla, CA 92037.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1694041" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Antigen-Presenting Cells/immunology ; Bone Marrow/immunology ; CD4-Positive T-Lymphocytes/immunology ; Clone Cells/immunology ; Epitopes/immunology ; Histocompatibility Antigens/*immunology ; Histocompatibility Antigens Class II/immunology ; *Immune Tolerance ; *Immunity ; Interleukin-2/physiology ; Mice ; Mice, Transgenic ; Receptors, Antigen, T-Cell/immunology ; T-Lymphocytes/*immunology ; T-Lymphocytes, Regulatory/immunology ; Thymus Gland/immunology
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  • 55
    Publication Date: 1990-11-23
    Description: In Aplysia sensory and motor neurons in culture, the contributions of the major classes of calcium current can be selectively examined while transmitter release and its modulation are examined. A slowly inactivating, dihydropyridine-sensitive calcium current does not contribute either to normal synaptic transmission or to any of three different forms of plasticity: presynaptic inhibition, homosynaptic depression, and presynaptic facilitation. This current does contribute, however, to a fourth form of plasticity--modulation of transmitter release by tonic depolarization of the sensory neuron. By contrast, a second calcium current, which is rapidly inactivating and dihydropyridine-insensitive, contributes to release elicited by the transient depolarization of an action potential and to the other three forms of plasticity.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Edmonds, B -- Klein, M -- Dale, N -- Kandel, E R -- New York, N.Y. -- Science. 1990 Nov 23;250(4984):1142-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Pharmacology, University College of London, United Kingdom.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2174573" target="_blank"〉PubMed〈/a〉
    Keywords: Action Potentials ; Animals ; Aplysia/*physiology ; Cadmium/pharmacology ; Calcium Channels/drug effects/*physiology ; Cells, Cultured ; Dihydropyridines/antagonists & inhibitors/pharmacology ; Electric Conductivity ; FMRFamide ; Motor Neurons/physiology ; Neuronal Plasticity/*physiology ; Neurons, Afferent/physiology ; Neuropeptides/pharmacology ; Nifedipine/pharmacology ; Serotonin/pharmacology ; Synapses/*physiology ; Synaptic Transmission/*physiology
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  • 56
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-01-05
    Description: The high degree of tubulin heterogeneity in neurons is controlled mainly at the posttranslational level. Several variants of alpha-tubulin can be posttranslationally labeled after incubation of cells with [3H]acetate or [3H]glutamate. Peptides carrying the radioactive moiety were purified by high-performance liquid chromatography. Amino acid analysis, Edman degradation sequencing, and mass spectrometric analysis of these peptides led to the characterization of a posttranslational modification consisting of the successive addition of glutamyl units on the gamma-carboxyl group of a glutamate residue (Glu445). This modification, localized within a region of alpha-tubulin that is important in the interactions of tubulin with microtubule-associated proteins and calcium, could play a role in regulating microtubule dynamics.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Edde, B -- Rossier, J -- Le Caer, J P -- Desbruyeres, E -- Gros, F -- Denoulet, P -- New York, N.Y. -- Science. 1990 Jan 5;247(4938):83-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratoire de Biochimie Cellulaire, College de France, Paris.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1967194" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acids/analysis ; Animals ; Brain/*metabolism ; Chromatography, High Pressure Liquid ; Glutamates/*metabolism ; Glutamic Acid ; Mass Spectrometry ; Mice ; Neurons/*metabolism ; Peptide Fragments/analysis ; *Protein Processing, Post-Translational ; Tubulin/*metabolism
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  • 57
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-06-15
    Description: During development in the thymus, T cells are rendered tolerant to self antigens. It is now apparent that thymocytes bearing self-reactive T cell receptors can be tolerized by processes that result in physical elimination (clonal deletion) or functional inactivation (clonal anergy). As these mechanisms have important clinical implications for transplantation and autoimmunity, current investigations are focused on understanding the cellular and molecular interactions that generate these forms of tolerance.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ramsdell, F -- Fowlkes, B J -- New York, N.Y. -- Science. 1990 Jun 15;248(4961):1342-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Cellular and Molecular Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1972593" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Antigens, Surface/immunology ; Autoantigens/immunology ; Autoimmunity/immunology ; Bone Marrow/immunology ; CD4-Positive T-Lymphocytes/immunology ; Chickens ; Chimera ; Clone Cells/*immunology ; H-2 Antigens/immunology ; Histocompatibility Antigens/immunology ; Histocompatibility Antigens Class II/immunology ; *Immune Tolerance ; Mice ; Mice, Transgenic ; Minor Lymphocyte Stimulatory Antigens ; Receptors, Antigen, T-Cell/*immunology ; T-Lymphocytes/*immunology ; T-Lymphocytes, Regulatory/immunology ; Thymus Gland/*immunology ; Xenopus
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  • 58
    Publication Date: 1990-06-01
    Description: Conjugate eye movements are executed through the concurrent activation of several muscles in both eyes. The neural mechanisms that underlie such synergistic muscle activations have been a matter of considerable experimentation and debate. In order to investigate this issue, the projections of a class of primate premotoneuronal cells were studied, namely, the vertical medium-lead burst neurons (VMLBs), which drive vertical rapid eye movements. Axons of upward VMLBs ramify bilaterally within motoneuron pools that supply the superior rectus and inferior oblique muscles of both eyes. Axons of downward VMLBs ramify ipsilaterally in the inferior rectus portion of the oculomotor nucleus and in the trochlear nucleus. Thus, VMLBs can drive vertical motoneuron pools of both eyes during conjugate vertical rapid eye movements; these data support Hering's law.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Moschovakis, A K -- Scudder, C A -- Highstein, S M -- EY-05433/EY/NEI NIH HHS/ -- EY-05954/EY/NEI NIH HHS/ -- NS-17763/NS/NINDS NIH HHS/ -- New York, N.Y. -- Science. 1990 Jun 1;248(4959):1118-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Neural Control, National Institute of Neurological Diseases and Stroke, Bethesda, MD 20892.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2343316" target="_blank"〉PubMed〈/a〉
    Keywords: Action Potentials ; Animals ; Axons/ultrastructure ; Eye Movements/*physiology ; *Models, Neurological ; Motor Neurons/cytology/*physiology/ultrastructure ; Neural Pathways/anatomy & histology/cytology ; Oculomotor Muscles/*innervation ; Saimiri
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  • 59
    Publication Date: 1990-01-12
    Description: The murine white spotting locus (W) is allelic with the proto-oncogene c-kit, which encodes a transmembrane tyrosine protein kinase receptor for an unknown ligand. Mutations at the W locus affect various aspects of hematopoiesis and the proliferation and migration of primordial germ cells and melanoblasts during development to varying degrees of severity. The W42 mutation has a particularly severe effect in both the homozygous and the heterozygous states. The molecular basis of the W42 mutation was determined. The c-kit protein products in homozygous mutant mast cells were expressed normally but displayed a defective tyrosine kinase activity in vitro. Nucleotide sequence analysis of mutant complementary DNAs revealed a missense mutation that replaces aspartic acid with asparagine at position 790 in the c-kit protein product. Aspartic acid-790 is a conserved residue in all protein kinases. These results provide an explanation for the dominant nature of the W42 mutation and provide insight into the mechanism of c-kit-mediated signal transduction.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Tan, J C -- Nocka, K -- Ray, P -- Traktman, P -- Besmer, P -- P01-CA-16599/CA/NCI NIH HHS/ -- R01-CA-32926/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 1990 Jan 12;247(4939):209-12.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Molecular Biology Program, Sloan Kettering Institute, New York, NY 10021.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1688471" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Base Sequence ; Cells, Cultured ; DNA/genetics ; Gene Expression ; Homozygote ; Liver/analysis/cytology/embryology ; Mast Cells/metabolism ; Mice ; Molecular Sequence Data ; *Mutation ; *Phenotype ; Polymerase Chain Reaction ; Protein-Tyrosine Kinases/*genetics ; Proto-Oncogene Proteins/*genetics ; Proto-Oncogene Proteins c-kit ; RNA/analysis ; Receptors, Cell Surface/genetics ; Signal Transduction
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  • 60
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-06-01
    Description: In many organisms, interactions between cells play a critical role in the specification of cell fates. In the sea urchin embryo, primary mesenchyme cells (PMCs) regulate the developmental program of a subpopulation of secondary mesenchyme cells (SMCs). The timing of this cell interaction was analyzed by means of a fluorescence photoablation technique, which was used to specifically ablate PMCs at various stages of development. In addition, the PMCs were microinjected into PMC-depleted recipient embryos at different developmental stages and their effect on SMC fate was examined. The critical interaction between PMCs and SMCs was brief and took place late in gastrulation. Before that time, SMCs were insensitive to the suppressive signals transmitted by the PMCs.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ettensohn, C A -- HD24690/HD/NICHD NIH HHS/ -- New York, N.Y. -- Science. 1990 Jun 1;248(4959):1115-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2188366" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cell Communication/*physiology ; Cell Survival/radiation effects ; Fluorescent Antibody Technique ; Fluorescent Dyes ; Light ; Mesoderm/*cytology/radiation effects ; Microinjections ; Rhodamines ; Sea Urchins/embryology
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  • 61
    Publication Date: 1990-07-27
    Description: There is currently a need for vaccine development to improve the immunogenicity of protective epitopes, which themselves are often poorly immunogenic. Although the immunogenicity of these epitopes can be enhanced by linking them to highly immunogenic carriers, such carriers derived from current vaccines have not proven to be generally effective. One reason may be related to epitope-specific suppression, in which prior vaccination with a protein can inhibit the antibody response to new epitopes linked to the protein. To circumvent such inhibition, a peptide from tetanus toxoid was identified that, when linked to a B cell epitope and injected into tetanus toxoid-primed recipients, retained sequences for carrier but not suppressor function. The antibody response to the B cell epitope was enhanced. This may be a general method for taking advantage of previous vaccinations in the development of new vaccines.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Etlinger, H M -- Gillessen, D -- Lahm, H W -- Matile, H -- Schonfeld, H J -- Trzeciak, A -- New York, N.Y. -- Science. 1990 Jul 27;249(4967):423-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Central Research Unit F. Hoffmann-La Roche, Basel, Switzerland.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1696030" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Antigens, Protozoan/*immunology ; B-Lymphocytes/immunology ; Epitopes/*immunology ; Humans ; Mice ; Mice, Inbred BALB C ; Molecular Sequence Data ; Peptide Fragments/immunology ; Plasmodium falciparum/*immunology ; T-Lymphocytes/immunology ; T-Lymphocytes, Helper-Inducer/immunology ; T-Lymphocytes, Regulatory/immunology ; Tetanus Toxoid/*immunology ; *Vaccination ; Vaccines/*immunology
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  • 62
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-09-21
    Description: Nonobese diabetic (NOD) mice develop an autoimmune form of diabetes, becoming hyperglycemic after 3 months of age. This process was accelerated by injecting young NOD mice with CD4+ islet-specific T cell clones derived from NOD mice. Overt diabetes developed in 10 of 19 experimental animals by 7 weeks of age, with the remaining mice showing marked signs of the disease in progress. Control mice did not become diabetic and had no significant pancreatic infiltration. This work demonstrates that a CD4 T cell clone is sufficient to initiate the disease process in the diabetes-prone NOD mouse.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Haskins, K -- McDuffie, M -- P01 DK40144/DK/NIDDK NIH HHS/ -- New York, N.Y. -- Science. 1990 Sep 21;249(4975):1433-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Barbara Davis Center for Childhood Diabetes, University of Colorado Health Sciences Center, Denver 80262.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2205920" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Antigens, CD4/analysis/*immunology ; Clone Cells ; Diabetes Mellitus, Experimental/*immunology/pathology ; Female ; Islets of Langerhans/*immunology/pathology ; Male ; Mice ; Mice, Inbred Strains ; Mice, Mutant Strains ; T-Lymphocytes/*immunology/transplantation
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  • 63
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-04-27
    Description: Light-dependent expression of rbcS, the gene encoding the small subunit of ribulose-1,5-bisphosphate carboxylase, which is the key enzyme involved in carbon fixation in higher plants, is regulated at the transcriptional level. Sequence analysis of the gene has uncovered a conserved GT motif in the -150 to -100 region of many rbcS promoters. This motif serves as the binding site of a nuclear factor, designated GT-1. Analysis of site-specific mutants of pea rbcS-3A promoter demonstrated that GT-1 binding in vitro is correlated with light-responsive expression of the rbcS promoter in transgenic plants. However, it is not known whether factors other than GT-1 might also be required for activation of transcription by light. A synthetic tetramer of box II (TGTGTGGTTAATATG), the GT-1 binding site located between -152 to -138 of the rbcS-3A promoter, inserted upstream of a truncated cauliflower mosaic virus 35S promoter is sufficient to confer expression in leaves of transgenic tobacco. This expression occurs principally in chloroplast-containing cells, is induced by light, and is correlated with the ability of box II to bind GT-1 in vitro. The data show that the binding site for GT-1 is likely to be a part of the molecular light switch for rbcS activation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lam, E -- Chua, N H -- New York, N.Y. -- Science. 1990 Apr 27;248(4954):471-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Plant Molecular Biology, Rockefeller University, New York, NY 10021.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2330508" target="_blank"〉PubMed〈/a〉
    Keywords: Base Sequence ; Binding Sites ; Chloramphenicol O-Acetyltransferase/genetics ; Cloning, Molecular ; DNA-Binding Proteins/*metabolism ; Gene Expression Regulation/*physiology ; Genetic Vectors ; *Light ; Molecular Sequence Data ; Mutation ; Nuclear Proteins/*metabolism ; Plant Proteins/*metabolism ; *Plants, Toxic ; Promoter Regions, Genetic/genetics ; Ribulose-Bisphosphate Carboxylase/*genetics ; Tobacco/enzymology/*genetics ; Transcription, Genetic/radiation effects ; Transformation, Genetic
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  • 64
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-07-13
    Description: Some animals have larger brains than others, but it is not yet known why. Species differences in life-style, including dietary habits and patterns of development of the young, are associated with variation in brain weight, independently of the effects of body weight and evolutionary history. Taken together with behavioral and neuroanatomical analyses, these studies begin to suggest the evolutionary pressures that favor different sized brains and brain components.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Harvey, P H -- Krebs, J R -- New York, N.Y. -- Science. 1990 Jul 13;249(4965):140-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Zoology, University of Oxford, United Kingdom.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2196673" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Biological Evolution ; Body Weight ; Brain/*anatomy & histology ; Humans ; Organ Size
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  • 65
    Publication Date: 1990-06-29
    Description: The human immunodeficiency virus (HIV) tat protein (Tat) is a positive regulator of virus gene expression and replication. Biotinylated Tat was used as a probe to screen a lambda gt11 fusion protein library, and a complementary DNA encoding a protein that interacts with Tat was cloned. Expression of this protein, designated TBP-1 (for Tat binding protein-1), was observed in a variety of cell lines, with expression being highest in human cells. TBP-1 was localized predominantly in the nucleus, which is consistent with the nuclear localization of Tat. In cotransfection experiments, expression of TBP-1 was able to specifically suppress Tat-mediated transactivation. The strategy described may be useful for direct identification and cloning of genes encoding proteins that associate with other proteins to modulate their activity in a positive or negative fashion.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Nelbock, P -- Dillon, P J -- Perkins, A -- Rosen, C A -- New York, N.Y. -- Science. 1990 Jun 29;248(4963):1650-3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Oncology and Virology, Roche Institute of Molecular Biology, Hoffmann-La Roche Inc., Nutley, NJ 07110.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2194290" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Cell Line ; Cloning, Molecular ; DNA, Neoplasm/genetics ; DNA-Binding Proteins/*genetics/metabolism ; Escherichia coli/genetics ; Gene Expression ; Gene Library ; Gene Products, tat/*metabolism ; HIV/genetics ; Humans ; Molecular Sequence Data ; Plasmids ; Polymerase Chain Reaction ; *Proteasome Endopeptidase Complex ; Recombinant Fusion Proteins/metabolism ; Trans-Activators/*metabolism ; Transcriptional Activation ; Transfection ; tat Gene Products, Human Immunodeficiency Virus
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  • 66
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-01-05
    Description: Feeding behavior of Aplysia is associated with an arousal state characterized by a constellation of maintained behaviors and by a potentiation or depression of responses to specific stimuli. A neuron (the cerebral-pedal regulator or CPR) that has widespread actions on various systems connected with feeding has been identified. CPR excites neurons that modulate or drive (i) body posture, (ii) biting, and (iii) cardiovascular behaviors. CPR also inhibits neurons concerned with defensive responses. Food stimuli, which elicit food arousal in the animal, produce prolonged excitation of the CPR. The results suggest that the CPR may evoke a central motive state representing the neuronal correlate of feeding motivation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Teyke, T -- Weiss, K R -- Kupfermann, I -- GM-320099/GM/NIGMS NIH HHS/ -- MH 35564/MH/NIMH NIH HHS/ -- New York, N.Y. -- Science. 1990 Jan 5;247(4938):85-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Center for Neurobiology and Behavior, College of Physicians and Surgeons, Columbia University, New York, NY 10032.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2294596" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Aplysia/*physiology ; Arousal/physiology ; Cardiovascular Physiological Phenomena ; Feeding Behavior/physiology ; Muscles/physiology ; Neurons/*physiology
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  • 67
    Publication Date: 1990-03-23
    Description: In Hermissenda crassicornis conditioned to associate light and rotation, type B photoreceptor neurons exhibit pairing-specific decreases in the potassium currents IA and IK-Ca, which account for many of the behavioral changes elicited by associative conditioning. To determine which proteins are involved in storage of this memory, high-performance liquid chromatography was used to examine proteins from Hermissenda eyes. Conditioning-specific changes in four phosphoproteins were observed 24 hours after conditioning. One of these proteins, cp20, was purified to apparent homogeneity and found to be a G protein. When injected back into Hermissenda type B cells, cp20 reduced IK and IK-Ca in a manner indistinguishable from the reduction caused by conditioning, suggesting that this protein may play a crucial role in memory acquisition or retention.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Nelson, T J -- Collin, C -- Alkon, D L -- New York, N.Y. -- Science. 1990 Mar 23;247(4949 Pt 1):1479-83.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Molecular and Cellular Neurobiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2108498" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Chromatography, High Pressure Liquid ; Chromatography, Ion Exchange ; Conditioning (Psychology)/physiology ; Eye Proteins/isolation & purification/physiology ; GTP-Binding Proteins/*isolation & purification/physiology ; Learning/physiology ; Mollusca/*metabolism ; Phosphoproteins/isolation & purification/physiology ; Potassium/*metabolism ; Potassium Channels/physiology
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  • 68
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-12-07
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Doolittle, R F -- New York, N.Y. -- Science. 1990 Dec 7;250(4986):1319.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2255900" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Biological Evolution ; Epidermal Growth Factor/*genetics ; Species Specificity ; Vaccinia virus/analysis
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  • 69
    Publication Date: 1990-07-13
    Description: The heterotrimeric guanine nucleotide-binding regulatory proteins act at the inner surface of the plasma membrane to relay information from cell surface receptors to effectors inside the cell. These G proteins are not integral membrane proteins, yet are membrane associated. The processing and function of the gamma subunit of the yeast G protein involved in mating-pheromone signal transduction was found to be affected by the same mutations that block ras processing. The nature of these mutations implied that the gamma subunit was polyisoprenylated and that this modification was necessary for membrane association and biological activity. A microbial screen was developed for pharmacological agents that inhibit polyisoprenylation and that have potential application in cancer therapy.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Finegold, A A -- Schafer, W R -- Rine, J -- Whiteway, M -- Tamanoi, F -- CA 41996/CA/NCI NIH HHS/ -- GM 07183/GM/NIGMS NIH HHS/ -- GM 35827/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1990 Jul 13;249(4965):165-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry and Molecular Biology, University of Chicago, IL 60637.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1695391" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Cell Membrane/metabolism ; Cloning, Molecular ; Epitopes/genetics ; GTP-Binding Proteins/genetics/*metabolism ; Hemagglutinins, Viral/immunology ; Lovastatin/pharmacology ; Mevalonic Acid/pharmacology ; Molecular Sequence Data ; Mutation ; Oncogene Protein p21(ras)/genetics/*metabolism ; Orthomyxoviridae/immunology ; Protein Processing, Post-Translational ; Saccharomyces cerevisiae/*genetics/metabolism ; Signal Transduction ; Suppression, Genetic
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  • 70
    Publication Date: 1990-07-27
    Description: The major autophosphorylation sites of the rat beta II isozyme of protein kinase C were identified. The modified threonine and serine residues were found in the amino-terminal peptide, the carboxyl-terminal tail, and the hinge region between the regulatory lipid-binding domain and the catalytic kinase domain. Because this autophosphorylation follows an intrapeptide mechanism, extraordinary flexibility of the protein is necessary to phosphorylate the three regions. Comparison of the sequences surrounding the modified residues showed no obvious recognition motif nor any similarity to substrate phosphorylation sites, suggesting that proximity to the active site may be the primary criterion for their phosphorylation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Flint, A J -- Paladini, R D -- Koshland, D E Jr -- DK09765/DK/NIDDK NIH HHS/ -- New York, N.Y. -- Science. 1990 Jul 27;249(4967):408-11.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular and Cellular Biology, University of California, Berkeley 94720.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2377895" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Binding Sites ; Brain/enzymology ; Cloning, Molecular ; Isoenzymes/genetics/*metabolism ; Molecular Sequence Data ; Peptide Fragments/isolation & purification/metabolism ; Phosphorylation ; Protein Conformation ; Protein Kinase C/genetics/*metabolism ; Rats ; Recombinant Proteins/metabolism ; Signal Transduction ; Trypsin
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  • 71
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-10-26
    Description: The Ca2+ that activates contraction in heart muscle is regulated as in skeletal muscle by processes that depend on voltage and intracellular Ca2+ and involve a positive feedback system. How the initial electrical signal is amplified in heart muscle has remained controversial, however. Analogous protein structures from skeletal muscle and heart muscle have been identified physiologically and sequenced; these include the Ca2+ channel of the sarcolemma and the Ca2+ release channel of the sarcoplasmic reticulum. Although the parallels found in cardiac and skeletal muscles have provoked valuable experiments in both tissues, separation of the effects of voltage and intracellular Ca2+ on sarcoplasmic reticulum Ca2+ release in heart muscle has been imperfect. With the use of caged Ca2+ and flash photolysis in voltage-clamped heart myocytes, effects of membrane potential in heart muscle cells on Ca2+ release from intracellular stores have been studied. Unlike the response in skeletal muscle, voltage across the sarcolemma of heart muscle does not affect the release of Ca2+ from the sarcoplasmic reticulum, suggesting that other regulatory processes are needed to control Ca2(+)-induced Ca2+ release.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Niggli, E -- Lederer, W J -- HL25675/HL/NHLBI NIH HHS/ -- HL36974/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1990 Oct 26;250(4980):565-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physiology, University of Maryland, School of Medicine, Baltimore 21201.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2173135" target="_blank"〉PubMed〈/a〉
    Keywords: Acetates/pharmacology ; Animals ; Calcium/*metabolism/pharmacology ; Calcium Channels/physiology ; Carrier Proteins/antagonists & inhibitors/physiology ; Ethylenediamines/pharmacology ; Feedback ; Guinea Pigs ; Heart/*physiology ; Membrane Potentials ; Myocardial Contraction/*physiology ; Myocardium/*metabolism ; Photolysis ; Sarcolemma/physiology ; Sarcoplasmic Reticulum/physiology ; Sodium-Calcium Exchanger
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  • 72
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-04-20
    Description: The role of sodium-calcium exchange at the sarcolemma in the release of calcium from cardiac sarcoplasmic reticulum was investigated in voltage-clamped, isolated cardiac myocytes. In the absence of calcium entry through voltage-dependent calcium channels, membrane depolarization elicited release of calcium from ryanodine-sensitive internal stores. This process was dependent on sodium entry through tetrodotoxin-sensitive sodium channels. Calcium release under these conditions was also dependent on extracellular calcium concentration, suggesting a calcium-induced trigger release mechanism that involves calcium entry into the cell by sodium-calcium exchange. This sodium current-induced calcium release mechanism may explain, in part, the positive inotropic effects of cardiac glycosides and the negative inotropic effects of a variety of antiarrhythmic drugs that interact with cardiac sodium channels. In response to a transient rise of intracellular sodium, sodium-calcium exchange may promote calcium entry into cardiac cells and trigger sarcoplasmic calcium release during physiologic action potentials.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Leblanc, N -- Hume, J R -- HL30143/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1990 Apr 20;248(4953):372-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physiology, University of Nevada School of Medicine, Reno 89557-0046.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2158146" target="_blank"〉PubMed〈/a〉
    Keywords: Action Potentials ; Animals ; Calcium/*metabolism/pharmacology ; Carrier Proteins/*metabolism ; Electric Conductivity ; Gallopamil/pharmacology ; Guinea Pigs ; Myocardial Contraction ; Myocardium/*metabolism ; Nisoldipine/pharmacology ; Sarcoplasmic Reticulum/*metabolism ; Sodium/metabolism ; Sodium Channels/drug effects/*physiology ; Sodium-Calcium Exchanger ; Tetrodotoxin/pharmacology
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  • 73
    Publication Date: 1990-05-11
    Description: Chronic granulomatous diseases (CGDs) are characterized by recurrent infections resulting from impaired superoxide production by a phagocytic cell, nicotinamide adenine dinucleotide phosphate (reduced) (NADPH) oxidase. Complementary DNAs were cloned that encode the 67-kilodalton (kD) cytosolic oxidase factor (p67), which is deficient in 5% of CGD patients. Recombinant p67 (r-p67) partially restored NADPH oxidase activity to p67-deficient neutrophil cytosol from these patients. The p67 cDNA encodes a 526-amino acid protein with acidic middle and carboxyl-terminal domains that are similar to a sequence motif found in the noncatalytic domain of src-related tyrosine kinases. This motif was recently noted in phospholipase C-gamma, nonerythroid alpha-spectrin (fodrin), p21ras-guanosine triphophatase-activating protein (GAP), myosin-1 isoforms, yeast proteins cdc-25 and fus-1, and the 47-kD phagocyte oxidase factor (p47), which suggests the possibility of common regulatory features.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Leto, T L -- Lomax, K J -- Volpp, B D -- Nunoi, H -- Sechler, J M -- Nauseef, W M -- Clark, R A -- Gallin, J I -- Malech, H L -- I01 BX000513/BX/BLRD VA/ -- New York, N.Y. -- Science. 1990 May 11;248(4956):727-30.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Clinical Investigation, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1692159" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Base Sequence ; Cloning, Molecular ; Granulomatous Disease, Chronic/blood/enzymology/genetics ; Humans ; Molecular Sequence Data ; NADH, NADPH Oxidoreductases/blood/*genetics ; NADPH Oxidase ; Neutrophils/*enzymology ; Protein-Tyrosine Kinases/genetics ; Proto-Oncogene Proteins/*genetics ; Proto-Oncogene Proteins pp60(c-src) ; Sequence Homology, Nucleic Acid
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  • 74
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-05-18
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Levitzki, A -- New York, N.Y. -- Science. 1990 May 18;248(4957):794.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biological Chemistry, Hebrew University of Jerusalem, Israel.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2188357" target="_blank"〉PubMed〈/a〉
    Keywords: Guanine Nucleotides/*metabolism ; Guanosine Diphosphate/*metabolism ; Guanosine Triphosphate/*metabolism ; Mutation ; Oncogene Protein p21(ras)/genetics/*metabolism ; Proto-Oncogene Proteins/genetics/*metabolism ; Proto-Oncogene Proteins p21(ras) ; Saccharomyces cerevisiae/genetics/metabolism ; Schizosaccharomyces/genetics/metabolism
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  • 75
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-12-21
    Description: Transcription of the mouse alpha-fetoprotein gene is activated in the developing fetal liver and gut and repressed in both tissues shortly after birth. With germline transformation in mice, a cis-acting element was identified upstream of the transcription initiation site of the alpha-fetoprotein gene that was responsible for repression of the gene in adult liver. This negative element acts as a repressor in a position-dependent manner.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Vacher, J -- Tilghman, S M -- CA44976/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 1990 Dec 21;250(4988):1732-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Howard Hughes Medical Institute, Department of Biology, Princeton University, NJ 08544.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1702902" target="_blank"〉PubMed〈/a〉
    Keywords: Aging ; Animals ; Animals, Newborn ; Chromosome Deletion ; Cloning, Molecular ; DNA-Binding Proteins/metabolism ; Enhancer Elements, Genetic ; Fetus ; *Gene Expression Regulation ; Hepatocyte Nuclear Factor 1 ; Hepatocyte Nuclear Factor 1-alpha ; Hepatocyte Nuclear Factor 1-beta ; Liver/growth & development/*metabolism ; Mice ; *Nuclear Proteins ; Transcription Factors/metabolism ; Transcription, Genetic ; alpha-Fetoproteins/*genetics
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  • 76
    Publication Date: 1990-08-03
    Description: Phosphoenolpyruvate carboxykinase (PEPCK) governs the rate-limiting step in gluconeogenesis. Glucocorticoids and adenosine 3',5'-monophosphate (cAMP) increase PEPCK gene transcription and gluconeogenesis, whereas insulin has the opposite effect. Insulin is dominant, since it prevents cAMP and glucocorticoid-stimulated transcription. Glucocorticoid and cAMP response elements have been located in the PEPCK gene and now a 15-base pair insulin-responsive sequence (IRS) is described. Evidence for a binding activity that recognizes this sequence is presented.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉O'Brien, R M -- Lucas, P C -- Forest, C D -- Magnuson, M A -- Granner, D K -- DK 20593/DK/NIDDK NIH HHS/ -- DK 35107/DK/NIDDK NIH HHS/ -- New York, N.Y. -- Science. 1990 Aug 3;249(4968):533-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Physiology and Biophysics, Vanderbilt University Medical School, Nashville, TN 37232-0615.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2166335" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Base Sequence ; Cell Line ; Chloramphenicol O-Acetyltransferase/genetics/metabolism ; Cyclic AMP/analogs & derivatives/physiology ; Dexamethasone/pharmacology ; *Genes, Regulator ; Insulin/*pharmacology ; Molecular Sequence Data ; Phosphoenolpyruvate Carboxykinase (GTP)/*genetics/metabolism ; RNA, Messenger/drug effects/genetics ; Recombinant Fusion Proteins/metabolism ; Thionucleotides ; Transcription, Genetic/*drug effects ; Transfection
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  • 77
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-05-11
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hoffman, M -- New York, N.Y. -- Science. 1990 May 11;248(4956):685-6.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2333520" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Antigens, Bacterial/*immunology ; Antigens, Viral/immunology ; Bacterial Toxins/*immunology ; Humans ; Immune System/*physiology ; Lymphocytes/*immunology ; Mice ; T-Lymphocytes/immunology
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  • 78
    Publication Date: 1990-06-22
    Description: The vast repertoire of immunoglobulins and T cell receptors is generated, in part, by V(D)J recombination, a series of genomic rearrangements that occur specifically in developing lymphocytes. The recombination activating gene, RAG-1, which is a gene expressed exclusively in maturing lymphoid cells, was previously isolated. RAG-1 inefficiently induced V(D)J recombinase activity when transfected into fibroblasts, but cotransfection with an adjacent gene, RAG-2, has resulted in at least a 1000-fold increase in the frequency of recombination. The 2.1-kilobase RAG-2 complementary DNA encodes a putative protein of 527 amino acids whose sequence is unrelated to that of RAG-1. Like RAG-1, RAG-2 is conserved between species that carry out V(D)J recombination, and its expression pattern correlates precisely with that of V(D)J recombinase activity. In addition to being located just 8 kilobases apart, these convergently transcribed genes are unusual in that most, if not all, of their coding and 3' untranslated sequences are contained in single exons. RAG-1 and RAG-2 might activate the expression of the V(D)J recombinase but, more likely, they directly participate in the recombination reaction.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Oettinger, M A -- Schatz, D G -- Gorka, C -- Baltimore, D -- GM39458/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1990 Jun 22;248(4962):1517-23.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Whitehead Institute for Biomedical Research, Cambridge, MA 02142.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2360047" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Base Sequence ; Biological Evolution ; Cattle ; Cell Line ; Chickens ; Cricetinae ; DNA/*genetics ; DNA Nucleotidyltransferases/*genetics ; *DNA-Binding Proteins ; Dogs ; Female ; *Gene Rearrangement, B-Lymphocyte ; *Gene Rearrangement, T-Lymphocyte ; *Homeodomain Proteins ; Humans ; Male ; Mice ; Molecular Sequence Data ; *Multigene Family ; Nuclear Proteins ; Nucleic Acid Hybridization ; Opossums ; Proteins/*genetics ; Rabbits ; Recombination, Genetic/*genetics ; Restriction Mapping ; Transfection ; Turtles ; VDJ Recombinases
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  • 79
    Publication Date: 1990-12-21
    Description: Ten strains of a new arbovirus belonging to the Bunyamwera group (Bunyaviridae) were recovered from field-collected Aedes albopictus mosquitoes in Potosi, Missouri. This evidence indicates that this species may serve as an arbovirus vector in the United States. The urban-suburban distribution, aggressive biting behavior, and broad viral susceptibility of Ae. albopictus may lead to the transmission of viruses of known public health importance and perhaps of viruses hitherto not transmitted to humans because of the feeding pattern of their usual vectors.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Francy, D B -- Karabatsos, N -- Wesson, D M -- Moore, C G Jr -- Lazuick, J S -- Niebylski, M L -- Tsai, T F -- Craig, G B Jr -- New York, N.Y. -- Science. 1990 Dec 21;250(4988):1738-40.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Division of Vector-Borne Infectious Diseases, Centers for Disease Control, U.S. Public Health Service, Fort Collins, CO 80522.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2270489" target="_blank"〉PubMed〈/a〉
    Keywords: Aedes/*microbiology ; Animals ; Arboviruses/*isolation & purification ; Asia ; Humans ; Insect Vectors ; United States
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  • 80
    Publication Date: 1990-08-31
    Description: The possibility has been explored that a subset of physiologically identifiable cells in the visual cortex is especially suited for the processing of stereoscopic depth information. First, characteristics of a disparity detector that would be useful for such processing were outlined. Then, a method was devised by which detailed binocular response data were obtained from cortical cells. In addition, a model of the disparity detector was developed that includes a plausible hierarchical arrangement of cortical cells. Data from the cells compare well with the requirements for the archetypal disparity detector and are in excellent agreement with the predictions of the model. These results demonstrate that a specific type of cortical neuron exhibits the desired characteristics of a disparity detector.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ohzawa, I -- DeAngelis, G C -- Freeman, R D -- EY01175/EY/NEI NIH HHS/ -- New York, N.Y. -- Science. 1990 Aug 31;249(4972):1037-41.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Group in Neurobiology, School of Optometry, University of California, Berkeley 94720.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2396096" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cats ; *Depth Perception ; Mathematics ; Models, Neurological ; Neurons/*physiology ; Vision, Binocular ; Visual Cortex/*physiology
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  • 81
    Publication Date: 1990-08-10
    Description: The interaction of the T cell receptor for antigen (TCR) with its antigen-major histocompatibility complex ligand is difficult to study because both are cell surface multimers. The TCR consists of two chains (alpha and beta) that are complexed to the five or more nonpolymorphic CD3 polypeptides. A soluble form of the TCR was engineered by replacing the carboxyl termini of alpha and beta with signal sequences from lipid-linked proteins, making them susceptible to enzymatic cleavage. In this manner, TCR heterodimers can be expressed independently of the CD3 polypeptides and in significant quantities (0.5 milligram per week). This technique seems generalizable to biochemical and structural studies of many other cell surface molecules as well.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lin, A Y -- Devaux, B -- Green, A -- Sagerstrom, C -- Elliott, J F -- Davis, M M -- New York, N.Y. -- Science. 1990 Aug 10;249(4969):677-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Howard Hughes Medical Institute, Stanford University School of Medicine, CA 94305-5402.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1696397" target="_blank"〉PubMed〈/a〉
    Keywords: Alkaline Phosphatase/genetics ; Amino Acid Sequence ; Animals ; Antigens, CD3 ; Antigens, CD55 ; Antigens, Differentiation, T-Lymphocyte/genetics ; Cell Line ; Complement Inactivator Proteins/genetics ; Female ; Humans ; Macromolecular Substances ; Membrane Proteins/genetics ; Molecular Sequence Data ; Placenta/enzymology ; Pregnancy ; Protein Sorting Signals/genetics ; Receptors, Antigen, T-Cell/*genetics ; Transfection
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  • 82
    Publication Date: 1990-12-07
    Description: A molecular clone of the Xenopus laevis ets-2 gene was isolated from an oocyte complementary DNA library. The amount of messenger RNA (mRNA) in each oocyte or embryo was almost constant during oogenesis and was maintained until the blastula stage of embryonic development, indicating that the observed 3.2-kilobase transcript is a maternal message. The only normal adult tissue in which ets-2 mRNA was detected was the ovary. Injection of antisense oligonucleotides homologous to the ets-2 sequence into oocytes led to degradation of the mRNA and blocked hormone-induced germinal vesicle breakdown. The ets-2 product is thus required for the meiotic maturation of Xenopus oocytes.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Chen, Z Q -- Burdett, L A -- Seth, A K -- Lautenberger, J A -- Papas, T S -- New York, N.Y. -- Science. 1990 Dec 7;250(4986):1416-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Molecular Oncology, National Cancer Institute, Frederick, MD 21702.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2255913" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cell Division ; *DNA-Binding Proteins ; Embryo, Nonmammalian/physiology ; Female ; Gene Expression ; Gene Library ; Oligonucleotides, Antisense/pharmacology ; Oocytes/cytology/drug effects/*physiology ; Oogenesis ; Protein-Tyrosine Kinases/genetics ; Proto-Oncogene Protein c-ets-2 ; Proto-Oncogene Proteins/*genetics ; *Proto-Oncogenes ; RNA, Messenger/analysis/genetics ; *Repressor Proteins ; *Trans-Activators ; *Transcription Factors ; Transcription, Genetic ; Xenopus laevis
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  • 83
    Publication Date: 1990-08-24
    Description: Soluble antigens (Ags) in the extracellular fluids are excluded from the class I major histocompatibility complex (MHC)-restricted pathway of Ag presentation in most cells. However, an exogenous Ag can be internalized, processed, and presented in association with class I MHC molecules on specialized Ag-presenting cells (APCs). These APCs express class II molecules and can simultaneously present exogenous Ags to both class I and class II MHC-restricted T cells. These APCs may be important participants in the regulation of host immune responses. This APC activity may explain several phenomena of cytotoxic T lymphocyte (CTL) priming in vivo and might be exploited for eliciting CTL responses to protein vaccines.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Rock, K L -- Gamble, S -- Rothstein, L -- AI-20248/AI/NIAID NIH HHS/ -- New York, N.Y. -- Science. 1990 Aug 24;249(4971):918-21.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Pathology, Harvard Medical School, Boston, MA 02115.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2392683" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Antigen-Presenting Cells/*immunology ; Azides/pharmacology ; Cell Line ; Histocompatibility Antigens Class I/*immunology ; Histocompatibility Antigens Class II/immunology ; Mice ; Mice, Inbred C57BL ; Ovalbumin/*immunology ; Spleen/immunology ; T-Lymphocytes/drug effects/immunology ; T-Lymphocytes, Cytotoxic/immunology
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  • 84
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-10-26
    Description: Expression of the L-arabinose BAD operon in Escherichia coli is regulated by AraC protein which acts both positively in the presence of arabinose to induce transcription and negatively in the absence of arabinose to repress transcription. The repression of the araBAD promoter is mediated by DNA looping between AraC protein bound at two sites near the promoter separated by 210 base pairs, araI and araO2. In vivo and in vitro experiments presented here show that an AraC dimer, with binding to half of araI and to araO2, maintains the repressed state of the operon. The addition of arabinose, which induces the operon, breaks the loop, and shifts the interactions from the distal araO2 site to the previously unoccupied half of the araI site. The conversion between the two states does not require additional binding of AraC protein and appears to be driven largely by properties of the protein rather than being specified by the slightly different DNA sequences of the binding sites. Slight reorientation of the subunits of AraC could specify looping or unlooping by the protein. Such a mechanism could account for regulation of DNA looping in other systems.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lobell, R B -- Schleif, R F -- GM18277/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1990 Oct 26;250(4980):528-32.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Graduate Department of Biochemistry, Brandeis University, Waltham, MA 02254.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2237403" target="_blank"〉PubMed〈/a〉
    Keywords: AraC Transcription Factor ; Arabinose/genetics/pharmacology ; *Bacterial Proteins ; Binding Sites ; *DNA, Bacterial/genetics/metabolism ; DNA, Superhelical/metabolism ; Escherichia coli/*genetics ; Escherichia coli Proteins ; Fucose/pharmacology ; Gene Expression Regulation, Bacterial/*drug effects ; Guanine/metabolism ; Macromolecular Substances ; Methylation ; Mutation ; Nucleic Acid Conformation/*drug effects ; Operon ; Protein Conformation/drug effects ; Repressor Proteins/metabolism/*pharmacology ; *Transcription Factors
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  • 85
    Publication Date: 1990-09-21
    Description: Thyrotropin (TSH), luteinizing hormone (LH), and chorionic gonadotropin (CG) are structurally related glycoprotein hormones, which bind to receptors that share a high degree of sequence similarity. However, comparison of the primary amino acid sequences of the TSH and LH-CG receptors reveals two unique insertions of 8 and 50 amino acids in the extracellular domain of the TSH receptor. The functional significance of these insertions were determined by site-directed mutagenesis. Deletion of the 50-amino acid tract (residues 317 to 366) had no effect on TSH binding or on TSH and thyroid-stimulating immunoglobulin (TSI) biological activities. In contrast, either deletion or substitution of the eight-amino acid region (residues 38 to 45) abolished these activities. This eight-amino acid tract near the amino terminus of the TSH receptor appears to be an important site of interaction for both TSH and TSI.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wadsworth, H L -- Chazenbalk, G D -- Nagayama, Y -- Russo, D -- Rapoport, B -- DK-19289/DK/NIDDK NIH HHS/ -- DK-36182/DK/NIDDK NIH HHS/ -- New York, N.Y. -- Science. 1990 Sep 21;249(4975):1423-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Medicine, Veterans Administration Medical Center, San Francisco, CA 94121.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2169649" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Base Sequence ; Binding Sites ; Cell Line ; Chromosome Deletion ; Clone Cells ; Cyclic AMP/metabolism ; Humans ; Molecular Sequence Data ; Mutation ; Oligonucleotide Probes ; Receptors, Thyrotropin/*genetics/metabolism ; Thyrotropin/*metabolism/pharmacology ; Transfection
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  • 86
    Publication Date: 1990-07-20
    Description: Animal lines selected for differences in drug sensitivity can be used to help determine the molecular basis of drug action. Long-sleep (LS) and short-sleep (SS) mice differ markedly in their genetic sensitivity to ethanol. To investigate the molecular basis for this difference, mRNA from brains of LS and SS mice was expressed in Xenopus oocytes and the ethanol sensitivity of gamma-aminobutyric acid A (GABAA)- and N-methyl D-aspartate (NMDA)-activated ion channels was tested. Ethanol facilitated GABA responses in oocytes injected with mRNA from LS mice but antagonized responses in oocytes injected with mRNA from SS animals. Ethanol inhibited NMDA responses equally in the two lines. Thus, genes coding for the GABAA receptor or associated proteins may be critical determinants of individual differences in ethanol sensitivity.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wafford, K A -- Burnett, D M -- Dunwiddie, T V -- Harris, R A -- AA03527/AA/NIAAA NIH HHS/ -- AA06399/AA/NIAAA NIH HHS/ -- New York, N.Y. -- Science. 1990 Jul 20;249(4966):291-3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Pharmacology, University of Colorado Health Sciences Center, Denver.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1695761" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Aspartic Acid/analogs & derivatives/pharmacology ; Brain/*metabolism ; Chloride Channels ; Chlorides/*physiology ; Diazepam/pharmacology ; Ethanol/*pharmacology ; Female ; Ion Channels/drug effects/physiology ; Membrane Proteins/*physiology ; Mice ; Mice, Inbred Strains ; Microinjections ; N-Methylaspartate ; Oocytes/*drug effects/*physiology ; RNA, Messenger/administration & dosage/genetics ; Receptors, GABA-A/drug effects/*genetics ; Xenopus ; gamma-Aminobutyric Acid/pharmacology
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  • 87
    Publication Date: 1990-06-22
    Description: Homologous or agonist-specific desensitization of beta-adrenergic receptors is thought to be mediated by a specific kinase, the beta-adrenergic receptor kinase (beta ARK). However, recent data suggest that a cofactor is required for this kinase to inhibit receptor function. The complementary DNA for such a cofactor was cloned and found to encode a 418-amino acid protein homologous to the retinal protein arrestin. The protein, termed beta-arrestin, was expressed and partially purified. It inhibited the signaling function of beta ARK-phosphorylated beta-adrenergic receptors by more than 75 percent, but not that of rhodopsin. It is proposed that beta-arrestin in concert with beta ARK effects homologous desensitization of beta-adrenergic receptors.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lohse, M J -- Benovic, J L -- Codina, J -- Caron, M G -- Lefkowitz, R J -- DK19318/DK/NIDDK NIH HHS/ -- HL16037/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1990 Jun 22;248(4962):1547-50.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Howard Hughes Medical Institute, Department of Medicine, Biochemistry and Cell Biology, Durham, NC 27710.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2163110" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Antigens/*genetics/isolation & purification/pharmacology ; Arrestin ; Blotting, Northern ; Chromatography, Ion Exchange ; Cloning, Molecular ; *Cyclic AMP-Dependent Protein Kinases ; DNA/genetics ; Eye Proteins/*genetics/isolation & purification/pharmacology ; Gene Expression Regulation ; Molecular Sequence Data ; Phosphodiesterase Inhibitors/*pharmacology ; Phosphorylation ; Protein Kinases/*pharmacology ; RNA, Messenger/analysis ; Receptors, Adrenergic, beta/*drug effects/physiology ; Transfection ; beta-Adrenergic Receptor Kinases
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  • 88
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-09-21
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Abelson, P H -- New York, N.Y. -- Science. 1990 Sep 21;249(4975):1357.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2402628" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Carcinogenicity Tests/*methods ; *Carcinogens ; Mutation ; *Rodentia
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  • 89
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-04-20
    Description: Cytotoxic T lymphocytes (CTLs) recognize class I major histocompatibility complex (MHC) molecules associated with antigenic peptides derived from endogenously synthesized proteins. Binding to such peptides is a requirement for class I assembly in the endoplasmic reticulum (ER). A mutant human cell line, T2, assembles and transports to its surface some, but not all, class I MHC molecules. The class I molecules expressed on the surface of T2 do not present peptides derived from cytosolic antigens, although they can present exogenously added peptides to CTL. The transported class I molecules may interact weakly with an unknown retaining factor in the ER such that they can assemble despite the relative shortage of peptides.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hosken, N A -- Bevan, M J -- AI-19335/AI/NIAID NIH HHS/ -- New York, N.Y. -- Science. 1990 Apr 20;248(4953):367-70.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Immunology, Research Institute of Scripps Clinic, La Jolla, CA 92037.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2326647" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Antigen-Presenting Cells/*immunology ; Antigens/immunology ; Antigens, Viral/immunology ; B-Lymphocytes/immunology ; Capsid/immunology ; Cell Line ; Endoplasmic Reticulum/immunology ; Gene Expression ; H-2 Antigens/genetics/immunology ; HLA Antigens/genetics ; Histocompatibility Antigens Class I/*immunology ; Histocompatibility Antigens Class II/genetics ; Humans ; Mice ; Mutation ; Ovalbumin/immunology ; Peptides/immunology ; T-Lymphocytes, Cytotoxic/immunology ; Transfection ; Tumor Cells, Cultured ; Viral Core Proteins/immunology
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  • 90
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-07-13
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Cherfas, J -- New York, N.Y. -- Science. 1990 Jul 13;249(4965):124-6.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2371561" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Animals, Genetically Modified/*genetics ; Humans ; Scotland ; Sheep/*genetics
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  • 91
    Publication Date: 1990-11-09
    Description: Cytokine synthesis inhibitory factor (CSIF; interleukin-10), a product of mouse TH2 T cell clones that inhibits synthesis of cytokines by mouse TH1 T cell clones, exhibits extensive sequence similarity to an uncharacterized open reading frame in the Epstein-Barr virus BCRF1. Recombinant BCRF1 protein mimics the activity of interleukin-10, suggesting that BCRF1 may have a role in the interaction of the virus with the host's immune system.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hsu, D H -- de Waal Malefyt, R -- Fiorentino, D F -- Dang, M N -- Vieira, P -- de Vries, J -- Spits, H -- Mosmann, T R -- Moore, K W -- New York, N.Y. -- Science. 1990 Nov 9;250(4982):830-2.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Immunology, DNAX Research Institute, Palo Alto, CA 94304.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2173142" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cell Line ; DNA, Viral/genetics ; Electrophoresis, Polyacrylamide Gel ; *Gene Expression Regulation, Viral ; Herpesvirus 4, Human/genetics/*immunology ; Humans ; Interleukin-10 ; Interleukins/*biosynthesis ; Killer Cells, Natural/immunology ; Mice ; Radioimmunoprecipitation Assay ; T-Lymphocytes/immunology ; Viral Proteins/genetics/*immunology
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    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 92
    Publication Date: 1990-05-25
    Description: Lesions of atherosclerosis occur in the innermost layer of the artery wall and consist primarily of proliferated smooth muscle cells surrounded by large amounts of connective tissue, numerous lipid-laden macrophages, and varying numbers of lymphocytes. Growth-regulatory molecules may be involved in intimal accumulation and proliferation of smooth muscle cells responsible for the occlusive lesions of atherosclerosis. Platelet-derived growth factor (PDGF) B-chain protein was found within macrophages in all stages of lesion development in both human and nonhuman primate atherosclerosis. Thus macrophages may play a critical role in the disease by providing PDGF, a potent chemotactic and growth-stimulatory molecule, to the intimal smooth muscle cells.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ross, R -- Masuda, J -- Raines, E W -- Gown, A M -- Katsuda, S -- Sasahara, M -- Malden, L T -- Masuko, H -- Sato, H -- HL-18645/HL/NHLBI NIH HHS/ -- HL-29873/HL/NHLBI NIH HHS/ -- RR-00166/RR/NCRR NIH HHS/ -- New York, N.Y. -- Science. 1990 May 25;248(4958):1009-12.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Pathology, University of Washington, Seattle 98195.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2343305" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Antibodies, Monoclonal/immunology ; Arteriosclerosis/*metabolism ; Blotting, Northern ; Diet, Atherogenic ; Humans ; Immunohistochemistry ; Macaca nemestrina ; Macrophages/*metabolism ; Monocytes/metabolism ; Platelet-Derived Growth Factor/genetics/*metabolism ; RNA, Messenger/genetics
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    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 93
    Publication Date: 1990-09-28
    Description: The erbB2 oncogene encodes a 185-kilodalton transmembrane protein whose sequence is similar to the epidermal growth factor receptor (EGFR). A 30-kilodalton factor (gp30) secreted from MDA-MB-231 human breast cancer cells was shown to be a ligand for p185erbB2. An antibody to EGFR abolished the tyrosine phosphorylation induced by EGF and transforming growth factor-alpha (TGF-alpha) but only partially blocked that produced by gp30 in SK-BR-3 breast cancer cells. In two cell lines that overexpress erbB2 but do not expresss EGFR (MDA-MB-453 breast cancer cells and a Chinese hamster ovary cell line that had been transfected with erbB2), phosphorylation of p185erbB2 was induced only by gp30. The gp30 specifically inhibited the growth of cells that overexpressed p185erbB2. An antibody to EGFR had no effect on the inhibition of SK-BR-3 cell colony formation obtained with gp30. Thus, it appeared that gp30 interacted directly with the EGFR and erbB2. Direct binding of gp30 to p185erbB2 was confirmed by binding competition experiments, where gp30 was found to displace the p185erbB2 binding of a specific antibody to p185erbB2. The evidence described here suggests that gp30 is a ligand for p185erbB2.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lupu, R -- Colomer, R -- Zugmaier, G -- Sarup, J -- Shepard, M -- Slamon, D -- Lippman, M E -- New York, N.Y. -- Science. 1990 Sep 28;249(4976):1552-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Vincent T. Lombardi Cancer Research Center, Georgetown University Medical Center, Washington, DC 20007.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2218496" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Antibodies, Monoclonal ; Binding, Competitive ; Breast Neoplasms ; Cell Line ; Chromatography, Affinity ; Female ; Humans ; Kinetics ; Ligands ; Molecular Weight ; Phosphorylation ; Protein-Tyrosine Kinases/metabolism ; Proto-Oncogene Proteins/genetics/immunology/*metabolism ; Proto-Oncogenes ; Receptor, Epidermal Growth Factor/isolation & purification/*metabolism ; Transfection
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  • 94
    Publication Date: 1990-02-16
    Description: In view of the current interest in in vivo murine models for acquired immunodeficiency syndrome (AIDS), the interaction between human immunodeficiency virus type 1 (HIV-1) and endogenous murine leukemia virus (MuLV)-related retroviruses was investigated with a human leukemic T cell line (PF-382x) that acquired xenotropic MuLV (X-MuLV) after in vivo passage in immunosuppressed mice. Despite similar levels of membrane CD4 expression and HIV-1 125I-labeled gp 120 binding, a dramatic acceleration in the time course of HIV-1 infection was observed in PF-382x compared to its X-MuLV-negative counterpart (PF-382). Moreover, PF-382 cells coinfected by X-MuLV and HIV-1 generated a progeny of phenotypically mixed viral particles, enabling HIV-1 to productively infect a panel of CD4- human cells, including B lymphoid cells and purified normal peripheral blood CD4-/CD8+ T lymphocytes. Mixed viral phenotypes were also produced by human CD4+ T cells coinfected with an amphotropic MuLV-related retrovirus (A-MuLV) and HIV-1. These data show that endogenous MuLV acquired by human cells transplanted into mice can significantly interact with HIV-1, thereby inducing important alterations of HIV-1 biological properties.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lusso, P -- di Marzo Veronese, F -- Ensoli, B -- Franchini, G -- Jemma, C -- DeRocco, S E -- Kalyanaraman, V S -- Gallo, R C -- New York, N.Y. -- Science. 1990 Feb 16;247(4944):848-52.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Tumor Cell Biology, National Cancer Institute, Bethesda, MD 20892.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2305256" target="_blank"〉PubMed〈/a〉
    Keywords: Acquired Immunodeficiency Syndrome/immunology ; Animals ; Antibodies, Monoclonal ; Antigens, CD4/analysis ; Cell Line ; Cell Transformation, Viral ; Disease Models, Animal ; HIV-1/*genetics/physiology ; Hematopoietic Stem Cells/cytology/microbiology ; Humans ; Mice ; Phenotype ; Retroviridae/*genetics ; Viral Proteins/analysis ; Virus Replication
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    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 95
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-10-26
    Description: The yeast protein RAP1, initially described as a transcriptional regulator, binds in vitro to sequences found in a number of seemingly unrelated genomic loci. These include the silencers at the transcriptionally repressed mating-type genes, the promoters of many genes important for cell growth, and the poly[(cytosine)1-3 adenine] [poly(C1-3A)] repeats of telomeres. Because RAP1 binds in vitro to the poly(C1-3A) repeats of telomeres, it has been suggested that RAP1 may be involved in telomere function in vivo. In order to test this hypothesis, the telomere tract lengths of yeast strains that contained conditionally lethal (ts) rap1 mutations were analyzed. Several rap1ts alleles reduced telomere length in a temperature-dependent manner. In addition, plasmids that contain small, synthetic telomeres with intact or mutant RAP1 binding sites were tested for their ability to function as substrates for poly(C1-3A) addition in vivo. Mutations in the RAP1 binding sites reduced the efficiency of the addition reaction.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lustig, A J -- Kurtz, S -- Shore, D -- GM 40094/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1990 Oct 26;250(4980):549-53.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Biology, Memorial Sloan-Kettering Cancer Center, New York, NY 10021.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2237406" target="_blank"〉PubMed〈/a〉
    Keywords: Base Sequence ; Binding Sites ; Chromosomes, Fungal/metabolism/*ultrastructure ; DNA-Binding Proteins/metabolism ; Fungal Proteins/genetics/*metabolism ; *Genes, Fungal ; *Genes, Mating Type, Fungal ; Molecular Sequence Data ; Mutation ; Plasmids ; Poly A/metabolism ; Poly C/metabolism ; Repetitive Sequences, Nucleic Acid ; Saccharomyces cerevisiae/*genetics ; Temperature ; *Transcription Factors ; Transformation, Genetic
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  • 96
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-03-09
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Rossi, H H -- New York, N.Y. -- Science. 1990 Mar 9;247(4947):1166-7.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2315689" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Humans ; Neoplasms, Radiation-Induced/*epidemiology ; Radiation Dosage ; Risk Factors
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    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 97
    Publication Date: 1990-07-20
    Description: Minor histocompatibility (H) antigens can be peptides derived from cellular proteins that are presented on the cell surface by major histocompatibility complex (MHC) class I molecules. This is similar to viral antigens, because in both cases cytotoxic T lymphocytes (CTLs) recognize artificially produced peptides loaded on target cells. Naturally processed minor H peptides were found to be similar to those artificial CTL-epitopes, as far as size and hydrophobicity is concerned. The peptides studied were isolated from a transfectant that expressed a model CTL-defined antigen, beta-galactosidase, from male cells that express H-Y, which has been known operationally since 1955, and from cells that express H-4, known since 1961.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Rotzschke, O -- Falk, K -- Wallny, H J -- Faath, S -- Rammensee, H G -- New York, N.Y. -- Science. 1990 Jul 20;249(4966):283-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Max-Planck-Institut fur Biologie, Abteilung Immungenetik, Tubingen, Federal Republic of Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1695760" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Epitopes/isolation & purification ; Female ; H-Y Antigen/*analysis/immunology ; Male ; Mice ; Mice, Inbred Strains ; Minor Histocompatibility Antigens/*analysis/immunology ; Molecular Sequence Data ; Peptides/chemical synthesis ; Species Specificity ; Spleen/immunology ; T-Lymphocytes, Cytotoxic/*immunology
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    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 98
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-02-02
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Cherfas, J -- New York, N.Y. -- Science. 1990 Feb 2;247(4942):523.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2300811" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Brain Diseases/microbiology/*veterinary ; Cattle ; Cattle Diseases/*microbiology ; Great Britain ; Virus Diseases/*veterinary
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    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 99
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-01-26
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Cherfas, J -- New York, N.Y. -- Science. 1990 Jan 26;247(4941):402-3.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2300801" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Antigens, Protozoan/genetics/immunology ; Genetic Variation ; Humans ; Malaria/*prevention & control ; Plasmodium/genetics/growth & development/immunology ; *Protozoan Proteins ; *Vaccines
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    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 100
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-01-26
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Cherfas, J -- New York, N.Y. -- Science. 1990 Jan 26;247(4941):400-1.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2300800" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Chloroquine/therapeutic use ; Humans ; Malaria/drug therapy/*prevention & control ; *Mosquito Control ; Plasmodium/immunology/physiology ; Vaccines ; World Health Organization
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    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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