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1.
TheLysobacter lactamgenus YK90pcbAB gene encoding -(l--aminoadipyl)-l-cysteinyl-d-valine (ACV) synthetase is located immediately upstream of thepcbC gene in the same orientation in the gene cluster involved in cephalosporin biosynthesis. ThepcbAB gene encodes a large polypeptide composed of 3722 amino acid residues with a molecular mass of 411 593 Da. The predicted amino acid sequence has a high degree of similarity with those of known ACV synthetases from fungi and actinomycetes. Within thepcbAB amino acid sequence, three conserved and repeated domains of about 600 amino acids were identified. The domains also share a high degree of similarity with non-ribosomal peptide synthetases such as gramicidin synthatase 2 ofBacillus brevis. ThepcbAB gene was expressed under the control of thelac promoter inPseudomonas putida. Expression of the gene cluster involved in cephalosporin biosynthesis inP. putida led to the accumulation of -lactam antibiotics. Deletion analysis of an open-reading frame located between thecefE andcefD genes from the gene cluster revealed that it encoded deacetylcephalosporin C synthetase (cefF). From the results presented here and those of previous studies, the genes involved in cephalosporin biosynthesis inL. lactamgenus appear to be clustered in the orderpcb AB-pcbC- cefE-cefF-cefD-bla in the same orientation within a 17-kb region of DNA.  相似文献   

2.
Summary The mating behavior of a number of brewer's and distiller's yeasts was determined with a and haploid and aa and diploid tester strains. Mating frequencies were not high, ranging from one to (rarely) 2,000/108 cells in the mating mixture. Sporulating hybrids were obtained in most matings, though the percentage spore viability initially obtained was often low. Notable the spore viability obtained in hybrids with the haploid tester strains and the brewing strains DIB and DICH was much higher than from the a haploid tester strain, and higher in hybrids between these strains and the aa diploid tester than in those from the tester strain. With the brewing strain NBA, the spore viability in hybrids with the a haploid tester strain was higher than in the case of strains DIB and DICH, but the spore viability in the hybrid of NBA x the haploid strain was higher still. The data are consistent with the hypothesis that with the a and aa tester strains, most of the industrial yeasts tested mate as diploids, and with the and testers, they mate as haploids, an hypothesis which is supported by the segregation of adenine markers in the progeny of these hybrids.Presented in part at the 6th International Specialized Symposium on Yeasts, Montpellier, France, 2–8 July, 1978  相似文献   

3.
Summary Homology maps between bacteriophages 81, 80 and were constructed on the basis of electron microscope observation of DNA heteroduplexes. In 81/80 heteroduplex, the left half and the right terminal region of 13% the total molecular length were highly homologous, while the remaining region covering the early gene cluster was entirely nonhomologous. In 81/ heteroduplex, high-degree homologies were detected at the left 14% terminal region covering the head gene cluster, the central 3.8% region covering the att-int-xis region and the 1.3% Q homology region. Low-degree homologies of shorter length were scattered at the tail gene cluster, b2 region, cIII region, PQ region and SR region. Comparing our results with the homology maps of other lambdoid phages reported by Simon et al. (1971) and Fiandt et al. (1971), a phylogenic relation of 81 to other lambdoid phages and the role of recombination in the course of divergence of lambdoid phages are discussed.  相似文献   

4.
The class II major histocompatibility complex antigens are cell-surface heterodimers consisting of an a and a chain. Cosmid cloning has shown that the three families of clas II antigens, DR, DQ, and DP, are encoded within the HLA-D region of chromosome 6 as a series of discrete gene clusters. The DP cluster contains two pairs of a and genes, one of which encodes the biochemically-defined DP antigen. In order to assess whether the other two genes, SXa and SX, are also expressed, potential coding regions have been subcloned and sequenced. The SX3 gene is shown to contain region closely homologous to all six exons of DP. A 1 bp deletion in the 2 exon, also observed for the SX4 allele, causes a translation frameshift, suggesting that SX is a pseudogene. However, all the other exons, as well as their splice sites and the putative promoter region, appear to be intact.  相似文献   

5.
In Arabidopsis tissues, the pool of tubulin protein is provided by the expression of multiple -tubulin and -tubulin genes. Previous evidence suggested that the TUA2 -tubulin gene was expressed in all organs of mature plants. We now report a more detailed analysis of TUA2 expression during plant development. Chimeric genes containing TUA2 5-flanking DNA fused to the -glucuronidase (GUS) coding region were used to create transgenic Arabidopsis plants. Second-generation progeny of regenerated plants were analyzed by histochemical assay to localize GUS expression. GUS activity was seen throughout plant development and in nearly all tissues. The blue product of GUS activity accumulated to the highest levels in tissues with actively dividing and elongating cells. GUS activity was not detected in a few plant tissues, suggesting that, though widely expressed, the TUA2 promoter is not constitutively active.  相似文献   

6.
Résumé Nous avons fait élever des larves d'Anergates atratulus par des ouvrières deMyrmica laevinodis à 22°C. Pour y parvenir, il n'est pas utile de faire hivernerensemble les larves d'Anergates et les ouvrières deMyrmica. La présence de larves autochtones n'empêche pas lesMyrmica d'élever des larves d'Anergates. Dans toutes les expériences lesMyrmica ont été soumises au fridavant de recevoir des larves d'Anergates. Aucune reine deMyrmica n'a été utilisée dans ces expériences.Sur les 64 larves d'Anergates que nous avons utilisées, 38 se sont transformées en imagos. C'est au début de l'adoption et au moment des métamorphoses que périrent la plupart des 26Anergates perdus. Les femelles vécurent en général 2 ou 3 jours et cherchèrent très tôt à quitter le nid natal. Les mâles vécurent 2 à 3 semaines.
Summary Larvae ofAnergates atratulus were experimentally reared by workers ofMyrmica laevinodis, at 22°C. An overwintering of both larvae ofAnergates and workers ofMyrmica is not necessary for the success of that experiment. The presence of larvae ofMyrmica does not keep theMyrmica from rearing larvae ofAnergates. The workers ofMyrmica have been cooled, in all the experiments, before receiving larvae ofAnergates. No queen ofMyrmica have been used in that experiments.38 of the 64 larvae ofAnergates used became imagos. Most of the 26 lostAnergates died at the beginning of the adoption and during the metamorphosis. The females lived generally 2 or 3 days and tried, very early, to leave their native nest. The males lived 2 or 3 weeks.

Anergates atratulus Myrmica laevinodis, 22 . bmecme Anergates Myrmica. Myrmica Anergates. Myrmica Anergates. Myrmica . 64 Anergates , 38 . 26 Anergates 2 3 . 2 3 .
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7.
The analysis of the absorption spectra of the low-molecular-weight nitrogen-containing secondary metabolites—alkaloids—of four Penicillium chrysogenum strains and six P. expansum strains isolated on board the Mir space station showed that all these strains synthesize metabolites of alkaloid origin (roquefortine, 3,12-dihydroroquefortine, meleagrin, viridicatin, viridicatol, isorugulosuvin, rugulosuvin B, N acetyltryptamine, and a yellow metabolite containing the benzoquinone chromophore).  相似文献   

8.
Summary A set of transducing phages carrying varying lengths of the E. coli chromosome around the structural gene for initiation factor IF3 (infC) was derived from p2 which is known to cary, besides infC, the structural genes for the subunit of phenylalanyl-tRNA synthetase (pheS), the subunit of phenylalanyl-tRNA synthetase (phetT) and the structural gene for threonyl-tRNA synthetase (thrS). The E. coli coding content of these derived phages was analysed by genetic complementation of a set of mutants and by SDS-polyacrylamide gel analysis of the proteins synthesized in UV irradiated cells infected with these phages. The segregation pattern of the different genes among these derived phages indicates that the order of the genes is pheT-pheS-P12-(infC, thrS) where infC is probably between P12 and thrS. P12 is the structural gene of a 12,000 molecular weight unidentified protein.Abbreviations PRS (EC 6.1.1.20) phenylalanyl-tRNA synthetase - TRS (EC 6.1.1.3) threonyl-tRNA synthetase - IF3 Initiation factor IF3 - SDS Sodium dodecyl sulfate - PPR pyrophosphate resistant - PPS pyrophosphate sensitive  相似文献   

9.
Summary The -tubulin genes G1 and G2 from the phytopathogenic hemiascomycete Geotrichum candidum were found to be highly diverged in amino acid sequence from those of other filamentous fungi. G1 and G2 were also divergent from each other, with the coding regions sharing only 66% nucleotide sequence homology and 64% amino acid identity. However, the proteins shared 82% similarity and only 25 of the 161 non-identical amino acid substitutions were non-conservative. The organization of G1 is similar to other fungal -tubulin genes, but G2 has several unusual features; it has 2 amino acid additions in the N-terminal 40 residues and must employ an uncommon 5 splice junction sequence in preference to an overlapping perfect consensus. The amino acid change found to confer benomyl resistance in Neurospora crassa was also present in G2. G1 has four introns which are located similarly to those of -tubulin genes in other fungi. G2, however, has a single intron in a unique location. Translational fusions employing the 5 non-coding regions of the two Geotrichum -tubulin genes were made with the hygromycin phosphotransferase gene and shown to function in Schizosaccharomyces pombe and Trichoderma hamatum. However, G. candidum could not be transformed with these or other tested plasmids commonly used for fungal transformation.  相似文献   

10.
In this study, the nucleotide sequences of the 3 untranslated regions (UTR) of the mouse and human c-fos genes, and the rat and human -actin genes were examined. It is shown (i) that the 3 UTR of c-fos is highly conserved between mouse and man, (ii) that multiple copies of a 12 bp element occur, in clusters, in the 3 UTR both of c-fos and of -actin. This conserved 12 bp element is analogous to the putative repressor binding site previously identified (Renan,Bioscience Reports,5 (1985), 739–753). These findings provide additional support for the proposal that regulatory signals are located in the 3 UTR's of certain genes.  相似文献   

11.
Different ζ globin gene deletions among Black Americans   总被引:7,自引:0,他引:7  
Summary Four types of chromosomes with a deletion between the human embryonic and globin genes were identified among 2.8% of 321 Black Americans from Georgia. Two deletions of approximately 11 kb which differed by about 300 bp occurred on chromosomes with or without a polymorphic Xba I site 5 to the globin gene [(X+) or (X-)]. The deletions are identifiable in Xba I digests of genomic DNA using an or a globin gene probe which yield fragments of 23 kb from (X+)–* chromosomes or 27 kb from (X)–* chromosomes. Digestion with other enzymes and probing with both and probes gave fragments typical of the two globin gene deletions previously identified in Polynesians. Among Black Americans, these globin gene deletions have been found in combination with globin gene deletions in trans but not in cis. Homozygotes have not been found. Hematologic data on carriers of the globin gene deletions in association with Hb AS, SS, and SC suggest that these deletions have no effect on the function of the adult globin genes.  相似文献   

12.
CD3 is an essential component of the CD3-TCR complex. In this report, we describe the cloning, characterization, and expression analysis of the CD3 and CD3/ chain genes from fugu, Takifugu rubripes. Two distinct CD3 homologue cDNAs, designated as CD3-1 and CD3-2, and a CD3/ homologue cDNA were isolated from the fugu thymus. The deduced amino acid sequences of these cDNAs exhibit conserved essential CD3 chain motifs and overall structures. RT-PCR analysis demonstrated that the CD3 and CD3/ genes were expressed in lymphoid organs (e.g. thymus, head kidney, trunk kidney and spleen), mucosal tissues (gill, skin, and intestine), and peripheral blood leucocytes (PBL). The CD3 and TCR genes were expressed only in the surface IgM population, which were separated from PBL using an anti-fugu IgM monoclonal antibody. In addition, in situ hybridization confirmed that CD3-expressing cells were distributed randomly in the head kidney, trunk kidney, and spleen, but in the thymus were restricted to the lymphoid outer zone and epithelioid inner zone only. Collectively, these results suggest that CD3 molecules are useful markers for the identification of T cells in teleost fish. The present study thus provides a critical step in identifying T cells in this model organism.Nucleotide sequence data reported in this paper are available in the DBJ/EMBL/GenBank databases and have been assigned the accession numbers AB166798 (CD3-1), AB166799 (CD3-2), and AB166800 (CD3/).  相似文献   

13.
In this work the protonmotive force (p), as well as the subcellular distribution of malate, ATP, and ADP were determined in perfused liver from rats fed a low fat or high fat diet, using density gradient fractionation in non acqueous solvents.Rats fed a high fat diet, despite an enhanced hepatic oxygen consumption, exhibit similar p to that found in rats fed a low fat diet, but when we consider the two components of p, we find a significant decrease in mitochondrial/cytosolic pH difference (pHm) and a significant increase in mitochondrial membrane potential (m) in rats fed a high fat diet compared to rats fed a low fat diet, which tend to compensate each other. In rats fed a high fat diet the concentration ratio of malate and ATP/ADP does not reflect the changes in pHm and m, which represent the respective driving force for their transport.The findings are in line with an increase in substrate supply to the respiratory chain which is, however, accompanied by a higher energy turnover in livers from HFD rats. By this way the liver could contribute to the lack of weight gain from the high caloric intake in HFD rats.  相似文献   

14.
Summary The constuction of two fused genes is described. One involves the in-frame fusion of the yeast prepro--factor coding sequence, and the Escherichia coli lac Z gene. The second gene fusion utilizes a 103 bp yeast invertase NH2-terminal coding sequence at the fusion junction of the hybrid gene described above. The gene fusions, under the control of the -factor promoter, expressed active -galactosidase in haploid yeast cells. The activity could be regulated in a temperature-sensitive sir3 mutant. The incorporation of the invertase coding sequence at the MF1-lacZ fusion junction provided significantly higher levels of -galactosidase activity. A substantial quantity of the hybrid proteins generated from the gene fusions was primarily localized in the intracellular membranes of yeast cells, while a processed form could be secreted into the periplasm.A portion of this work appeared in Biotechnology Progress (Das and Shultz 1986) as proceedings of the symposium on Industrial Scale Protein Purification, held at the annual meeting of the Institute of Chemical Engineers in Miami Beach, Fla, USA on November 4, 1986  相似文献   

15.
Hybridizations ofElymus nutans andE. jacquemontii were carried out with one species ofPseudoroegneria (S genome), and 20Elymus species, each containing either of the SH, SY, SYH, or SYW genomes. Chromosome configurations were analysed at metaphase I of the two target taxa and their interspecific hybrids. It is concluded that (i)E. nutans is an allohexaploid containing the SYH genomes, andE. jacquemontii is an allotetraploid having the SY genomes; (ii) the genomic affinity is associated with the geographic distance between the species studied; (iii) minor genomic structural rearrangements have occurred within the hexaploid taxon ofE. nutans.  相似文献   

16.
Extreme resistance in cultivated potato (Solanum tuberosum) to potato viruses Y and A (PVY and PVA) conditioned by the presence of Ry genes introduced from Solanum stoloniferum was described by Cockerham (1970). Cockerham detailed a number of genes which controlled a variety of reactions, including extreme resistance to both viruses (i.e. little or no visible reaction of plants and no viral replication following graft and manual inoculation) controlled by gene Ry sto. In the present study, cvs Pirola and Barbara, which contain a Ry gene, were found to have extreme resistance to PVY isolates from the ordinary (PVY°), veinal necrosis (PVYN) and potato tuber necrotic ringspot (PVYNTN) subgroups, and PVA. The inheritance of this phenotype was examined in seedling progenies obtained by crossing Barbara and Pirola with susceptible cultivars. Segregation data for resistance to PVY and PVA in a progeny involving cv Pirola best fitted a genetical model of one gene controlling extreme resistance to both PVY and PVA, although the possibility that there are two genes, each controlling resistance to one virus but closely linked, cannot be excluded. Segregation data from progenies involving cv Barbara best fitted a genetical model in which there are two independent genes, one controlling extreme resistance to PVA and PVY and a second gene controlling extreme resistance to PVA but not to PVY. This previously unrecognised gene conferring extreme resistance to PVA only, should be given the notation Ra in keeping with nomenclature used for other resistance genes.  相似文献   

17.
Summary Determinations of current-voltage relationships are widely employed in the characterization of epithelial sodium transport. In order to determine the protocol dependence of transport parameters in the toad urinary bladder, studies were carried out in the presence and absence of amiloride, an inhibitor of active sodium transport. With symmetric positive and negative perturbations of the transepithelial electrical potential difference (0±100 mV) for 30 sec, the amiloride-sensitive current-voltage (i a -) relationship was near linear over the range –75+100 mV, indicating constancy of the conductance a and the apparent electromotive force E Na, lumped parameters of the standard electrical equivalent circuit model of the active transport system. With a reverse protocol (±1000 mV) or 15 min perturbations thei a - relationships were highly nonlinear. Nonlinearity reflected voltage dependence of parameters: perturbations that increased active transport decreased E Na and increased a, as evaluated from 10 sec perturbations of ; slowing of active transport produced the converse changes. These effects are usefully analyzed in both quasi-steady states and true steady states by means of a detailed equivalent circuit incorporating the significant ionic currents across each plasma membrane. Precise understanding of the significance of a and E Na will require characterization of the partial ionic conductances on perturbation of .  相似文献   

18.
The synergistic effects of irradiance and salinity on leaf angle, the photochemical efficiency of photosystem II and photosynthetic pigment composition of mangroves were studied in a factorial experiment. Seedlings of Aegiceras corniculatum (L.) Blanco (Myrsinaceae) and Avicennia marina (Forstk.) Vierh var. australasica (Walp.) Moldenke (Avicenniaceae) were grown under salinity treatments (0, 5, 25, 50, 75, and 100% artificial seawater), in full sunlight or under shade cloth (transmitting 30 or 70% sunlight), during summer and autumn. Significant species differences and effects of salinity and growth irradiance were found for key measures. Depressions in Fv/Fm due to salinity and growth irradiance were chronic, they were least in 25% seawater and in 30% sunlight, and greater in low and high salinity, and higher irradiance. A diurnal depression of Fv/Fm was superimposed on the chronic depression, and was greater for Ae. corniculatum than Av. marina. Increases in leaf angle; and increases in the size, and de-epoxidation state of the xanthophyll cycle pigment pool afforded protection from adverse effects of excess excitation energy. Adverse effects of the highest salinities on ,-carotene and ,-carotene biosynthetic pathways were suggested, particularly in Ae. corniculatum. The ecological significance of differences in species extent and temporal patterns of response are discussed.  相似文献   

19.
Summary Endopeptidase zymograms of the translocation line Indis revealed the presence of several major and minor bands that had differential expression in coleoptile and seed tissues. While Indis lacks Ep-D1a, which is present in the parental cultivar Inia 66, it also may not express any of the Th. distichum bands. The Indis zymogram was found to be identical to that of an isogenic line of Inia 66 possessing Lr19. Since the absence of an Ep-D1a product appears to be linked to the 7DL translocation, it is possible to use the null condition as a marker for both the Lr19 or Indis translocations. The Indis translocation also did not show recombination with the cn-D1 chlorophyl mutant on 7DL, confirming that a part of 7D was involved. The results of a telocentric mapping experiment involving the 7D telosomes indicated that in Indis a chromosome segment from Th. distichum replaced a large section of 7DL of Inia 66.  相似文献   

20.
A human HLA-DQ -chain cDNA was used as a probe to identify and isolate a rat major histocompatibility antigen -chain gene from a genomic library constructed in the vector Charon 28 using Wistar rat DNA (RT1 u). The isolated exon of the rat gene (RT1.B 2) encoding a -chain second domain was found to share 93% nucleotide homology with a mouse A 2 exon. Although the genomic organization of this gene is consistent with the hypothesis that it represents a pseudogene, the remarkable preservation of a specific sequence favors the view that this class II antigen -chain gene has retained its coding function.  相似文献   

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