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Megan N. Hemming Sarah Fieg W. James Peacock Elizabeth S. Dennis Ben Trevaskis 《Molecular genetics and genomics : MGG》2009,282(2):107-117
Activity of the VERNALIZATION1 (VRN1) gene is required for flowering in temperate cereals such as wheat and barley. In varieties that require prolonged exposure
to cold to flower (vernalization), VRN1 is expressed at low levels and is induced by vernalization to trigger flowering. In other varieties, deletions or insertions
in the first intron of the VRN1 gene are associated with increased VRN1 expression in the absence of cold treatment, reducing or eliminating the requirement for vernalization. To characterize natural
variation in VRN1, the first intron of the barley (Hordeum vulgare) VRN1 gene (HvVRN1) was assayed for deletions or insertions in a collection of 1,000 barleys from diverse geographical regions. Ten alleles of
HvVRN1 containing deletions or insertions in the first intron were identified, including three alleles that have not been described
previously. Different HvVRN1 alleles were associated with differing levels of HvVRN1 expression in non-vernalized plants and with different flowering behaviour. Using overlapping deletions, we delineated regions
in the HvVRN1 first intron that are associated with low levels of HvVRN1 expression in non-vernalized plants. Deletion of these intronic regions does not prevent induction of HvVRN1 by cold or the maintenance of increased HvVRN1 expression following cold treatment. We suggest that regions within the first intron of HvVRN1 are required to maintain low levels of HvVRN1 expression prior to winter but act independently of the regulatory mechanisms that mediate induction of HvVRN1 by cold during winter.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Nucleotide sequence data reported are available in the DDBJ/EMBL/GenBank databases under the accession numbers 1179825, 1179833,
1179836, 1179858. 相似文献
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L. Wanntorp H.-E. Wanntorp B. Oxelman M. Källersjö 《Plant Systematics and Evolution》2001,226(1-2):85-107
The phylogeny of the genus Gunnera is investigated for the first time. Twelve species representing the six currently recognised subgenera are analysed. Two
chloroplast DNA regions, the rbcL gene and the rps16 intron, together provide 46 informative characters out of 2335. A combined analysis of both genes gives four most parsimonious
trees, firmly establishing the east South American G. herteri as sister group to the rest of the genus. The African G. perpensa is sister group to two well-supported clades, one including the South American subgenera Misandra and Panke, the other the Australian/New Zealand/Malayan species of subgenera Milligania and Pseudogunnera. Thus, South America is a composite area for Gunnera, showing up at two different levels in the cladogram. Our analysis supports a close biogeographic relationship between Australia
and New Zealand. The evolution of some morphological characters is discussed. Lastly, the unusual structure of some of the
rbcL sequences is reported.
Received July 6, 2000 Accepted October 24, 2000 相似文献
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The plasma membrane transport proteins belong to SoLute Carrier 15 (SLC15) family and two members of this family have been
characterized extensively in higher vertebrates, namely PEPT1 and PEPT2. Despite many efforts have made to define a pharmacophore
model for efficient binding and transporting of substrates, there is not a comprehensive study performed to elucidate the
evolutionary mechanisms among the SLC15 family members and to statistically evaluate sequence conservation and functional
divergence between members. In this study, we compared and contrasted the rates and patterns of molecular evolution of 2 PEPT genes. Phylogenetic tree assembly with all available vertebrate PEPTs suggests that the PEPTs originated by duplications and diverged from a common protein at the base of the eukaryotic tree. Topological structure demonstrates
both members share the similar hydrophobic domains (TMDs), which have been constrained by purifying selection. Although both
genes show qualitatively similar patterns, their rates of evolution differ significantly due to an increased rate of synonymous
substitutions in the structural domains in one copy, suggesting substantial differences in functional constraint on each gene.
Site-specific profiles were established by posterior probability analysis revealing significantly divergent regions mainly
locate at the hydrophobic region between predicted transmembrane domains 9 and 10 of the proteins. Thus, these results provide
the evidence that several amino acid residues with reduced selective constraints are largely responsible for functional divergence
between the paralogous PEPTs. These findings may provide a starting point for further experimental verifications. 相似文献
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Hiroyoshi Kubo 《Mycoscience》2009,50(5):400-406
Pilobolus crystallinus shows unique photoresponses at various growing stages. cDNAs for putative photoreceptors were cloned from this fungus. Three
genes named pcmada1, pcmada2, and pcmada3 were identified from the PCR fragments, and amplified with degenerated primers for the LOV domain, which is conserved in
many blue-light receptors. Deduced amino acid sequences for PCMADA1, PCMADA2, and PCMADA3 had one light-oxygen-voltage (LOV)-sensing
and two PER-ARNT-SIM (PAS) domains. A zinc finger DNA-binding motif was conserved in the C-terminals of PCMADA1 and PCMADA3.
However, PCMADA2 lacked the zinc finger motif. Expression of pcmada1 was suppressed by blue light whereas that of pcmada3 was promoted by blue-light irradiation. 相似文献
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O. V. Golovanova V. I. Konenkov A. V. Shevchenko M. V. Smolnikova 《Russian Journal of Genetics》2009,45(8):981-986
Based on population analysis of the DRB1, DQA1, DQB1 and TNFA allele frequency distribution patterns, regional features of immunogenetic structure of the population of West Siberia were
investigated. Statistically significant linkage disequilibrium within the HLA class II region, as well as between the TNFA and DRB1, DQA1, and DQB1 was demonstrated. Population frequency distribution patterns of two- and multilocus haplotypes were examined. 相似文献
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Elena Alcaide 《Current microbiology》2003,46(3):0184-0189
A numerical taxonomic study was performed on 148 isolates of Gram-negative, heterotrophic, facultative anaerobic bacteria
isolated from amberjack (Seriola dumerili) and its surrounding culture water. The study included 30 type and reference strains belonging to genera Vibrio, Listonella, and Photobacterium. The strains were characterized by 109 morphological, biochemical, physiological, and nutritional tests. Cluster analysis
of similarity matrices obtained with SSM and SJ coefficients was carried out. UPGMA (unweighted pair group mathematical average) analysis defined 11 phena at SSM values ≥ 86%. Nine phena were identified as Vibrio alginolyticus, V. fischeri, V. harveyi, V. carchariae, V. mediterranei, V. splendidus, V. furnissii, V. parahaemolyticus, and Photobacterium damselae subsp. damselae. The two latter comprised strains isolated from diseased fish.
Received: 27 March 2002 / Accepted: 24 May 2002 相似文献
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Karim Christina Scopinho Furquim Gervásio Henrique Bechara Maria Izabel Camargo Mathias 《Experimental & applied acarology》2010,50(1):59-70
This study describes the changes undergone by cells of the salivary glands of unfed and feeding (at day two and four post-attachment)
Rhipicephalus sanguineus males, as well as new cell types. In unfed males, types I and II acini are observed with cells “undifferentiated”, undefined
1 and 2 (the latter, with atypical granules), a, c1 and c3; type III is composed of cells d and e; and type IV present cells g. In males at day two post-attachment, type I acini exhibit the same morphology of unfed individuals. An increase in size
is observed in types II, III, and IV, as cells are filled with secretion granules. Some granules are still undergoing maturation.
In type II acinus, cells a, b and c1–c8 are observed. Cells c7 and c8 are described for the first time. Cells c7 are termed as such due to the addition of polysaccharides in the composition of the secretion granules (in unfed individuals,
they are termed undefined
1). Type III acini exhibit cells d and e completely filled with granules, and in type IV, cells g contain granules in several stages of maturation. In males at day four post-attachment, type I acini do not exhibit changes.
Granular acini exhibit cells with fewer secretion granules, which are already mature. In type II acini, cells a, b, c1–c5 are present, type III exhibit cells d and e, and type IV contain cells g with little or no secretion. This study shows that in the salivary glands of R.
sanguineus males, cells a, c1, and c3 of type II acinus, and cells d and e of type III do not exhibit changes in granular content, remaining continuously active during the entire feeding period. This
indicates that during the intervals among feeding stages, gland cells reacquire the same characteristics found in unfed individuals,
suggesting that they undergo reprogramming to be active in the next cycle. 相似文献
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Tomasz Jarzembowski Katarzyna Wiśniewska Agnieszka Jóźwik Jacek Witkowski 《Current microbiology》2009,59(1):78-80
We used fluorescent penicillin Bocillin FL for characterization of control methicillin-resistant Staphylococcus aureus (MRSA) strains belonging to one of four heterogenic classes and comparing them with clinical MRSA isolates. Significant differences
in percentage of fluorescent cells and reduction of Bocillin FL binding after incubation with methicillin between control
strains from classes I and IV were observed, whereas the strains from classes II and III were differed after incubation with
methicillin. According to this criteria, 55.8% of the clinical isolates population were similar to the strain of class IV
or homogenic resistant, 11.8% was found as I, and 32.3% were categorized as class II or III. However, continuous diversity
of measured features was also discussed. 相似文献
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Chiou CY Chen IP Chen C Wu HJ Wei NV Wallace CC Chen CA 《Journal of molecular evolution》2008,66(4):317-324
Calmodulin (CaM), belonging to the tropinin C (TnC) superfamily, is one of the calcium-binding proteins that are highly conserved
in their protein and gene structure. Based on the structure comparison among published vertebrate and invertebrate CaM, it is proposed that the ancestral form of eumetazoan CaM genes should have five exons and four introns (four-intron hypothesis). In this study, we determined the gene structure of
CaM in the coral Acropora muricata, an anthozoan cnidarian representing the basal position in animal evolution. A CaM clone was isolated from a cDNA library constructed from the spawned eggs of A. muricata. This clone was composed of 908 nucleotides, including 162 base pairs (bp) of 5′-untranslated region (UTR), 296 bp of 3′-UTR,
and an open reading frame 450 bp in length. The deduced amino acid indicated that the Acropora CaM protein is identical to that of the actiniarian, Metridinium senile, and has four putative calcium-binding domains highly similar to those of other vertebrate or invertebrate CaMs. Southern
blot analysis revealed that Acropora CaM is a putative single-copy gene in the nuclear genome. Genomic sequencing showed that Acropora CaM was composed of five exons and four introns, with intron II not corresponding to any region in the actiniarian CaM gene, which possesses only four exons and three introns. Our results highlight that the coral CaM gene isolated from A. muricata has four introns at the predicted positions of the early metazoan CaM gene organization, providing the first evidence from the basal eumetazoan phylum to support the four-intron hypothesis. 相似文献
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The accurate prediction of plant pre-mRNA splicing sites has been studied extensively. The rules for plant pre-mRNA splicing
still remain unknown. This study, based on confirmed sequence data, systematically analyzed all expressed genes on Arabidopsis thaliana chromosome IV to quantitatively explore the natural splicing rules. The results indicated that defining Arabidopsis thaliana pre-mRNA splicing sites required a combination of multiple factors including (1) relative conserved consensus sequence at
splicing site; (2) individual nucleotide distribution pattern in 50 nucleotides up- and down-stream regions of splicing site;
(3) quantitative analysis of individual nucleotide distribution by using the formulations concluded from this study. The combination
of all these factors together can bring the accuracy of Arabidopsis thaliana splicing site recognition over 99%. The results provide additional information to the future of plant pre-mRNA splicing research. 相似文献
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There are three most important bacterial causative agents of serious infections that could be misused for warfare purposes:
Bacillus anthracis (the causative agent of anthrax) is the most frequently mentioned one; however, Fracisella tularensis (causing tularemia) and Yersinia pestis (the causative agent of plague) are further bacterial agents enlisted by Centers for Disease Control and Prevention into the category A of potential biological weapons. This review intends to summarize basic information about these bacterial
agents. Military aspects of their pathogenesis and the detection techniques suitable for field use are discussed. 相似文献
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Nucleotide sequences polymorphism of mitochondrial nad1 gene b/c intron was studied in 41 Malus accessions and 21 related Rosaceae accessions. The b/c intron sequence in genus Malus appeared to be very conservative, while in other studied Rosaceae species 126 variable sites and indels were detected in the intron sequence that varied in length from 1124 to 1456 bp. The predicted b/c intron pre-mRNA secondary structure for Malus species was determined; IBS/EBS binding sites and the boundaries of the six functional domains were identified. 相似文献
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Background
DNA-dependent RNA polymerase IV and V (Pol IV and V) are multi-subunit enzymes occurring in plants. The origin of Pol V, specific to angiosperms, from Pol IV, which is present in all land plants, is linked to the duplication of the gene encoding the largest subunit and the subsequent subneofunctionalization of the two paralogs (NRPD1 and NRPE1). Additional duplication of the second-largest subunit, NRPD2/NRPE2, has happened independently in at least some eudicot lineages, but its paralogs are often subject to concerted evolution and gene death and little is known about their evolution nor their affinity with Pol IV and Pol V. 相似文献18.
Khomaini Hasan Wangsa Tirta Ismaya Idar Kardi Yandi Andiyana Susanti Kusumawidjaya Safri Ishmayana Toto Subroto Soetijoso Soemitro 《Biologia》2008,63(6):1044-1050
α-Amylase from Saccharomycopsis fibuligera R-64 was successfully purified by butyl Toyopearl hydrophobic interaction chromatography, followed by Sephadex G-25 size
exclusion and DEAE Toyopearl anion exchange chromatography. The enzyme has a molecular mass of 54 kDa, as judged by SDS PAGE
analysis. Upon tryptic digestion, two major fragments with relative molecular masses of 39 kDa and 10 kDa, which resemble
the A/B and C-terminal domains in the homologous Taka-amylase, were obtained and were successfully separated with the Sephadex
G-50 size exclusion column. The 39-kDa fragment demonstrated a similar amylolytic activity to that of the undigested enzyme.
However, it was found that the K
m value of the 39-kDa fragment was about two-times higher than that of the undigested enzyme. Moreover, thermostability studies
showed a lower half-life time for the 39-kDa fragment. These findings suggest that the 39-kDa fragment is the catalytic domain,
while the 10-kDa fragment is the C-terminal one, which plays a role in thermostability and starch binding. Although the undigested
enzyme is able to act on raw starches at room temperature, with maize starches as the best substrate, neither the undigested
enzyme nor the fragments adsorb the tested raw starches. These results propose Saccharomycopsis fibuligera α-amylase as a raw starch-digesting but not adsorbing amylase, with a similar domain organization to that of Taka-amylase A. 相似文献
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Joha W. Grobbelaar Z. Wilhelm de Beer Paulette Bloomer Michael J. Wingfield Xu Dong Zhou Brenda D. Wingfield 《Mycoscience》2011,52(2):111-118
Ophiostoma species such as O. quercus are the most frequent causal agents of sapstain of freshly felled hardwood timber and pulpwood. Many species are regarded
as economically important agents of wood degradation. The aim of this study was to identify a collection of Ophiostoma isolates, resembling O. quercus, found on stained Eucalyptus pulpwood chips in China. DNA sequences of the internal transcribed spacer regions, including the 5.8S region, of the ribosomal
DNA, and parts of the β-tubulin and elongation factor-1α genes, revealed that the isolates were not O. quercus. Surprisingly, they represented O. tsotsi, a wound-infesting fungus recently described from hardwoods in Africa. In addition, sequence data from an isolate from agarwood
in Vietnam, identified in a previous study as belonging to an unknown Pesotum species, were also shown to represent O. tsotsi. A high level of genetic variability was observed among isolates of both O. quercus and O. tsotsi. This was unexpected and suggests that both species have been present in Asia for a significant amount of time. 相似文献
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Drosophila lamin C (LamC) is a developmentally regulated component of the nuclear lamina. The lamC gene is situated in the fifth intron of the essential gene tout velu (ttv). We carried out genetic analysis of lamC during development. Phenotypic analyses of RNAi-mediated downregulation of lamC expression as well as targeted misexpression of lamin C suggest a role for lamC in cell survival. Of particular interest in the context of laminopathies is the caspase-dependent apoptosis induced by the
overexpression of lamin C. Interestingly, misexpression of lamin C in the central nervous system, where it is not normally
expressed, did not affect organization of the nuclear lamina. lamC mutant alleles suppressed position effect variegation normally displayed at near-centromeric and telomeric regions. Further,
both downregulation and misexpression of lamin C affected the distribution of heterochromatin protein 1. Our results suggest
that Drosophila lamC has a tissue-specific role during development and is required for chromatin organization. 相似文献