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1.
Thi Thanh Thuy Pham Abderrazzek Maaroufi Etienne Odier 《Applied microbiology and biotechnology》1990,33(1):99-104
Summary The progeny of Dichomitus squalens CBS-432-34 is heterogeneous with respect to specific growth rate on glucose, cellulolytic ([U14C]cellulose 14CO2) and ligninolytic ([14C]synthetic lignin 14CO2) activities with little correlation between these metric characters. Variations do not show clear-cut phenotypes but rather a continuous range between extreme values pointing to multigenic control of these characters. Most homocaryons showed decreased cellulolytic or ligninolytic activity compared to the parent dicaryon. However a few homocaryons were comparable or even superior to the parent dicaryon for ligninolytic or cellulolytic activity with no correlation between each factor. Strains with reduced cellulolytic activity and altered isozyme patterns of endoglucanases were isolated in the progeny of D. squalens CBS-432-34. While the parent strain produced three main endoglucanase multiple enzymes designated EnI, EnII and EnIII, several strains in the progeny produced a different multiple enzyme pattern. In contrast to the quantitative ability to degrade cellulose, multiple enzyme pattern variation in the progeny did not show continuous variations. characterization of heterocaryon phenotypes derived from Ien+ and Ien 1 homocaryons and first filial generation (f1) analysis showed that genetic control of the multiple enzyme pattern (Ien 1 phenotype) in D. squalens is complex.
Offprint requests to: E. Odier 相似文献
2.
Litman GW; Rast JP; Shamblott MJ; Haire RN; Hulst M; Roess W; Litman RT; Hinds- Frey KR; Zilch A; Amemiya CT 《Molecular biology and evolution》1993,10(1):60-72
Immunoglobulins are encoded by a large multigene system that undergoes
somatic rearrangement and additional genetic change during the development
of immunoglobulin-producing cells. Inducible antibody and antibody-like
responses are found in all vertebrates. However, immunoglobulin possessing
disulfide-bonded heavy and light chains and domain-type organization has
been described only in representatives of the jawed vertebrates. High
degrees of nucleotide and predicted amino acid sequence identity are
evident when the segmental elements that constitute the immunoglobulin gene
loci in phylogenetically divergent vertebrates are compared. However, the
organization of gene loci and the manner in which the independent elements
recombine (and diversify) vary markedly among different taxa. One striking
pattern of gene organization is the "cluster type" that appears to be
restricted to the chondrichthyes (cartilaginous fishes) and limits
segmental rearrangement to closely linked elements. This type of gene
organization is associated with both heavy- and light-chain gene loci. In
some cases, the clusters are "joined" or "partially joined" in the germ
line, in effect predetermining or partially predetermining, respectively,
the encoded specificities (the assumption being that these are expressed)
of the individual loci. By relating the sequences of transcribed gene
products to their respective germ-line genes, it is evident that, in some
cases, joined-type genes are expressed. This raises a question about the
existence and/or nature of allelic exclusion in these species. The
extensive variation in gene organization found throughout the vertebrate
species may relate directly to the role of intersegmental
(V<==>D<==>J) distances in the commitment of the individual
antibody-producing cell to a particular genetic specificity. Thus, the
evolution of this locus, perhaps more so than that of others, may reflect
the interrelationships between genetic organization and function.
相似文献
3.
ChaoChien Chang KeeChin Sia JiaFeng Chang ChiaMo Lin ChuenMao Yang ITa Lee Thi Thuy Tien Vo KuoYang Huang WeiNing Lin 《Journal of cellular and molecular medicine》2022,26(14):3850
Obesity is a world‐wide problem, especially the child obesity, with the complication of various metabolic diseases. Child obesity can be developed as early as the age between 2 and 6. The expansion of fat mass in child age includes both hyperplasia and hypertrophy of adipose tissue, suggesting the importance of proliferation and adipogenesis of preadipocytes. The changed composition of gut microbiota is associated with obesity, revealing the roles of lipopolysaccharide (LPS) on manipulating adipose tissue development. Studies suggest that LPS enters the circulation and acts as a pro‐inflammatory regulator to facilitate pathologies. Nevertheless, the underlying mechanisms behind LPS‐modulated obesity are yet clearly elucidated. This study showed that LPS enhanced the expression of cyclooxygenase‐2 (COX‐2), an inflammatory regulator of obesity, in preadipocytes. Pretreating preadipocytes with the scavenger of reactive oxygen species (ROS) or the inhibitors of NADPH oxidase or p42/p44 MAPK markedly decreased LPS‐stimulated gene expression of COX‐2 together with the phosphorylation of p47phox and p42/p44 MAPK, separately. LPS activated p42/p44 MAPK via NADPH oxidase‐dependent ROS accumulation in preadipocytes. Reduction of intracellular ROS or attenuation of p42/p44 MAPK activation both reduced LPS‐mediated COX‐2 expression and preadipocyte proliferation. Moreover, LPS‐induced preadipocyte proliferation and adipogenesis were abolished by the inhibition of COX‐2 or PEG2 receptors. Taken together, our results suggested that LPS enhanced the proliferation and adipogenesis of preadipocytes via NADPH oxidase/ROS/p42/p44 MAPK‐dependent COX‐2 expression. 相似文献
4.
QTLs for cell-membrane stability mapped in rice (Oryza sativa L.) under drought stress 总被引:14,自引:0,他引:14
J. N. Tripathy Jingxian Zhang S. Robin Thuy T. Nguyen H. T. Nguyen 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2000,100(8):1197-1202
Cell-membrane stability (CMS) is considered to be one of the major selection indices of drought tolerance in cereals. In order
to determine which genomic region is responsible for CMS, 104 rice (Oryza sativa L.) doubled haploid (DH) lines derived from a cross between CT9993–5-10–1-M and IR62266-42–6-2 were studied in the greenhouse
in a slowly developed drought stress environment. Drought stress was induced on 50-day-old plants by withholding water. The
intensity of stress was assessed daily by visual scoring of leaf wilting and by measuring leaf relative water content (RWC).
The leaf samples were collected from both control (well-watered) and stressed plants (at 60–65% of RWC), and the standard
test for CMS was carried out in the laboratory. There was no significant difference (P>0.05) in RWC between the two parental lines as well as among the 104 lines, indicating that all the plants were sampled at
a uniform stress level. However, a significant difference (P<0.05) in CMS was observed between the two parental lines and among the population. No significant correlation was found between
CMS and RWC, indicating that the variation in CMS was genotypic in nature. The continuous distribution of CMS and its broad-sense
heritability (34%) indicates that CMS should be polygenic in nature. A linkage map of this population comprising of 145 RFLPs,
153 AFLPs and 17 microsatellite markers was used for QTL analysis. Composite interval mapping identified nine putative QTLs
for CMS located on chromosomes 1, 3, 7, 8, 9, 11 and 12. The amount of phenotypic variation that was explained by individual
QTLs ranged from 13.4% to 42.1%. Four significant (P<0.05) pairs of digenic interactions between the detected QTLs for CMS were observed. The identification of QTLs for this
important trait will be useful in breeding for the improvement of drought tolerance in rice. This is the first report of mapping
QTLs associated with CMS under a natural water stress condition in any crop plants.
Received: 8 September 1999 / Accepted: 13 October 1999 相似文献
5.
Meadows SA Edosada CY Mayeda M Tran T Quan C Raab H Wiesmann C Wolf BB 《Biochemistry》2007,46(15):4598-4605
Fibroblast activation protein (FAP) and dipeptidyl peptidase-4 (DPP-4) are highly homologous serine proteases of the prolyl peptidase family and therapeutic targets for cancer and diabetes, respectively. Both proteases display dipeptidyl peptidase activity, but FAP alone has endopeptidase activity. FAP Ala657, which corresponds to DPP-4 Asp663, is important for endopeptidase activity; however, its specific role remains unclear, and it is unknown whether conserved DPP-4 substrate binding residues support FAP endopeptidase activity. Using site-directed mutagenesis and kinetic analyses, we show here that Ala657 and five conserved active site residues (Arg123, Glu203, Glu204, Tyr656, and Asn704) promote FAP endopeptidase activity via distinct mechanisms of transition state stabilization (TSS). The conserved residues provide marked TSS energy for both endopeptidase and dipeptidyl peptidase substrates, and structural modeling supports their function in binding both substrates. Ala657 also stabilizes endopeptidase substrate binding and additionally dictates FAP reactivity with transition state inhibitors, allowing tight interaction with tetrahedral intermediate analogues but not acyl-enzyme analogues. Conversely, DPP-4 Asp663 stabilizes dipeptidyl peptidase substrate binding and permits tight interaction with both transition state analogues. Structural modeling suggests that FAP Ala657 and DPP-4 Asp663 confer their contrasting effects on TSS by modulating the conformation of conserved residues FAP Glu204 and DPP-4 Glu206. FAP therefore requires the combined function of Ala657 and the conserved residues for endopeptidase activity. 相似文献
6.
7.
Mark J. Mitton-Fry Steven J. Brickner Judith C. Hamel Lori Brennan Jeffrey M. Casavant Michael Chen Tao Chen Xiaoyuan Ding James Driscoll Joel Hardink Thuy Hoang Erbing Hua Michael D. Huband Meghan Maloney Anthony Marfat Sandra P. McCurdy Dale McLeod Michael Plotkin Christopher Zook 《Bioorganic & medicinal chemistry letters》2013,23(10):2955-2961
A structurally novel set of inhibitors of bacterial type II topoisomerases with potent in vitro and in vivo antibacterial activity was developed. Dual-targeting ability, hERG inhibition, and pharmacokinetic properties were also assessed. 相似文献
8.
9.
Olendzenski L Liu L Zhaxybayeva O Murphey R Shin DG Gogarten JP 《Journal of molecular evolution》2000,51(6):587-599
Members of the Deinococcaceae (e.g., Thermus, Meiothermus, Deinococcus) contain A/V-ATPases typically found in Archaea or Eukaryotes which were probably acquired by horizontal gene transfer. Two methods were used to quantify the extent to which archaeal or eukaryotic genes have been acquired by this lineage. Screening of a Meiothermus ruber library with probes made against Thermoplasma acidophilum DNA yielded a number of clones which hybridized more strongly than background. One of these contained the prolyl tRNA synthetase (RS) gene. Phylogenetic analysis shows the M. ruber and D. radiodurans prolyl RS to be more closely related to archaeal and eukaryal forms of this gene than to the typical bacterial type. Using a bioinformatics approach, putative open reading frames (ORFs) from the prerelease version of the D. radiodurans genome were screened for genes more closely related to archaeal or eukaryotic genes. Putative ORFs were searched against representative genomes from each of the three domains using automated BLAST. ORFs showing the highest matches against archaeal and eukaryotic genes were collected and ranked. Among the top-ranked hits were the A/V-ATPase catalytic and noncatalytic subunits and the prolyl RS genes. Using phylogenetic methods, ORFs were analyzed and trees assessed for evidence of horizontal gene transfer. Of the 45 genes examined, 20 showed topologies in which D. radiodurans homologues clearly group with eukaryotic or archaeal homologues, and 17 additional trees were found to show probable evidence of horizontal gene transfer. Compared to the total number of ORFs in the genome, those that can be identified as having been acquired from Archaea or Eukaryotes are relatively few (approximately 1%), suggesting that interdomain transfer is rare. 相似文献
10.
Polymorphisms of interferon-inducible genes OAS-1 and MxA associated with SARS in the Vietnamese population 总被引:9,自引:0,他引:9
Hamano E Hijikata M Itoyama S Quy T Phi NC Long HT Ha LD Ban VV Matsushita I Yanai H Kirikae F Kirikae T Kuratsuji T Sasazuki T Keicho N 《Biochemical and biophysical research communications》2005,329(4):1234-1239
We hypothesized that host antiviral genes induced by type I interferons might affect the natural course of severe acute respiratory syndrome (SARS). We analyzed single nucleotide polymorphisms (SNPs) of 2',5'-oligoadenylate synthetase 1 (OAS-1), myxovirus resistance-A (MxA), and double-stranded RNA-dependent protein kinase in 44 Vietnamese SARS patients with 103 controls. The G-allele of non-synonymous A/G SNP in exon 3 of OAS-1 gene showed association with SARS (p=0.0090). The G-allele in exon 3 of OAS-1 and the one in exon 6 were in strong linkage disequilibrium and both of them were associated with SARS infection. The GG genotype and G-allele of G/T SNP at position -88 in the MxA gene promoter were found more frequently in hypoxemic group than in non-hypoxemic group of SARS (p=0.0195). Our findings suggest that polymorphisms of two IFN-inducible genes OAS-1 and MxA might affect susceptibility to the disease and progression of SARS at each level. 相似文献