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Regie?Lyn?P. Santos-Cortez Kwanghyuk Lee Zahid Azeem Patrick?J. Antonellis Lana?M. Pollock Saadullah Khan Irfanullah Paula?B. Andrade-Elizondo Ilene Chiu Mark?D. Adams Sulman Basit Joshua?D. Smith University of Washington Center?for?Mendelian Genomics Deborah?A. Nickerson Brian?M. McDermott Jr. Wasim Ahmad Suzanne?M. Leal 《American journal of human genetics》2013,93(1):132-140
Previously, DFNB89, a locus associated with autosomal-recessive nonsyndromic hearing impairment (ARNSHI), was mapped to chromosomal region 16q21–q23.2 in three unrelated, consanguineous Pakistani families. Through whole-exome sequencing of a hearing-impaired individual from each family, missense mutations were identified at highly conserved residues of lysyl-tRNA synthetase (KARS): the c.1129G>A (p.Asp377Asn) variant was found in one family, and the c.517T>C (p.Tyr173His) variant was found in the other two families. Both variants were predicted to be damaging by multiple bioinformatics tools. The two variants both segregated with the nonsyndromic-hearing-impairment phenotype within the three families, and neither mutation was identified in ethnically matched controls or within variant databases. Individuals homozygous for KARS mutations had symmetric, severe hearing impairment across all frequencies but did not show evidence of auditory or limb neuropathy. It has been demonstrated that KARS is expressed in hair cells of zebrafish, chickens, and mice. Moreover, KARS has strong localization to the spiral ligament region of the cochlea, as well as to Deiters’ cells, the sulcus epithelium, the basilar membrane, and the surface of the spiral limbus. It is hypothesized that KARS variants affect aminoacylation in inner-ear cells by interfering with binding activity to tRNA or p38 and with tetramer formation. The identification of rare KARS variants in ARNSHI-affected families defines a gene that is associated with ARNSHI. 相似文献
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Abdul Aziz Irfanullah Saadullah Khan Faridullah Khan Zimri Noor Muhammad Sajid Rashid Wasim Ahmad 《Gene》2014
Split-hand/split-foot malformation (SHFM), representing variable degree of median clefts of hands and feet, is a genetically heterogeneous group of limb malformations with seven loci mapped on different human chromosomes. However, only 3 genes (TP63, WNT10B, DLX5) for the seven loci have been identified. 相似文献
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Ecology of Dictyosphaerium pulchellum Wood (Chlorophyta, Chlorococcales) in a shallow, acid, forest lake 总被引:1,自引:0,他引:1
This study relates to the ecology of Dictyosphaerium pulchellum Wood in Delamere Lake in Cheshire, UK. Dictyosphaerium pulchellum is a cosmopolitan, green colonial phytoplankton species that occasionally forms dense, monospecific populations in lakes.
Delamere Lake is a small, shallow, acid lake (mean pH, 4.5) with very high phytoplankton biomass (annual mean chlorophyll
a, 290 μg l−1) and devoid of any significant cladoceran population, the efficient grazers of phytoplankton. A predominantly unicellular
form of D. pulchellum was the dominant species in Lake Delamere, and it comprised on average ca. 80% (maximum >99%) of the lake phytoplankton biovolume.
Laboratory and lake experiments were conducted on this species showed that its pH tolerance varied between 2.4 and 10.7, and
its optimum tolerance range between 3.3 and 8.5 depending on other environmental variables. Low pH was not responsible for
the unicellular habit of this alga, but a very high nutrient regime could be an important factor. Bioassays revealed that
in Delamere Lake this species was limited by nitrogen, but nitrogen did not hamper high growth in the lake. Dictyosphaerium pulchellum can persist at low light levels, tolerate CO2-deficiency and can grow in polyhumic water with water colour around 300 mg Pt l−1, but probably not in darker waters. The dominance of D. pulchellum in Delamere Lake is apparently due to a combination of several factors: its ability to tolerate both low pH and high turbidity,
exploit high nutrient conditions, absence of effective grazing pressure by zooplankton and being a superior competitor. 相似文献
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Algal Taxonomy in Limnology: An Example of the Declining Trend of Taxonomic Studies? 总被引:1,自引:0,他引:1
Haseeb Md. Irfanullah 《Hydrobiologia》2006,559(1):1-9
The recent decline in taxonomic studies is well recognized. Algae-related papers (390) published in five leading limnology
journals (1971–2004) were consulted to assess similar trends in limnology by taking algae as a test aquatic group. The study
showed a decrease of algae-only studies and an increase of multi-group studies (algae plus one or more aquatic groups). Identification
of species decreased while mentioning of ecological groups (phytoplankton, epiphytes, etc.) increased while presenting results.
Species identification, however, was not associated with number of aquatic groups or number of algal species included in a
study. Problems probably lie with the old-fashioned image of taxonomy and it being threatened by the recent advancement in
evolutionary and molecular biology. Issues like the changing research patterns in freshwater ecology, scope of limnological
works, its workers and relevant journals are also shaping the status of traditional taxonomy in limnology. Practices such
as giving of at least (algal) genera in community studies, and of the current names of studied species in physiological/molecular
works and also in studies on particular supra-generic taxa (Class, Family, etc.), could help sustaining of taxonomy in limnology. 相似文献
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Saadullah Khan Imran Ullah Irfanullah Muhammad Touseef Sulman Basit Muhammad Nasim Khan Wasim Ahmad 《Gene》2013
Bardet–Biedl syndrome (BBS) is an autosomal recessive disorder resulting from structural and functional defects in numerous organs. Frequent manifestations reported in the syndrome include obesity, renal dysplasia, cognitive impairment, postaxial polydactyly, pigmentary retinal degeneration and hypogonadism. To date, 17 genes causing BBS have been identified. Two of these BBS1 and BBS10 are the most frequently mutated genes. 相似文献
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