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941.
The Glycerol‐3‐Phosphate Acyltransferase TbGAT is Dispensable for Viability and the Synthesis of Glycerolipids in Trypanosoma brucei 下载免费PDF全文
Nipul Patel Karim A. Pirani Tongtong Zhu Melanie Cheung‐See‐Kit Sungsu Lee Daniel G. Chen Rachel Zufferey 《The Journal of eukaryotic microbiology》2016,63(5):598-609
Glycerolipids are the main constituents of biological membranes in Trypanosoma brucei, which causes sleeping sickness in humans. Importantly, they occur as a structural component of the glycosylphosphatidylinositol lipid anchor of the abundant cell surface glycoproteins procyclin in procyclic forms and variant surface glycoprotein in bloodstream form, that play crucial roles for the development of the parasite in the insect vector and the mammalian host, respectively. The present work reports the characterization of the glycerol‐3‐phosphate acyltransferase TbGAT that initiates the biosynthesis of ester glycerolipids. TbGAT restored glycerol‐3‐phosphate acyltransferase activity when expressed in a Leishmania major deletion strain lacking this activity and exhibited preference for medium length, unsaturated fatty acyl‐CoAs. TbGAT localized to the endoplasmic reticulum membrane with its N‐terminal domain facing the cytosol. Despite that a TbGAT null mutant in T. brucei procyclic forms lacked glycerol‐3‐phosphate acyltransferase activity, it remained viable and exhibited similar growth rate as the wild type. TbGAT was dispensable for the biosynthesis of phosphatidylcholine, phosphatidylinositol, phosphatidylserine, and GPI‐anchored protein procyclin. However, the null mutant exhibited a slight decrease in phosphatidylethanolamine biosynthesis that was compensated with a modest increase in production of ether phosphatidylcholine. Our data suggest that an alternative initial acyltransferase takes over TbGAT's function in its absence. 相似文献
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Understanding the genetic structure of a population is essential to its conservation and management. We report the level of genetic diversity and determine the population structure of a cryptic deep ocean cetacean, the Gray''s beaked whale (Mesoplodon grayi). We analysed 530 bp of mitochondrial control region and 12 microsatellite loci from 94 individuals stranded around New Zealand and Australia. The samples cover a large area of the species distribution (~6000 km) and were collected over a 22-year period. We show high genetic diversity (h=0.933–0.987, π=0.763–0.996% and Rs=4.22–4.37, He=0.624–0.675), and, in contrast to other cetaceans, we found a complete lack of genetic structure in both maternally and biparentally inherited markers. The oceanic habitats around New Zealand are diverse with extremely deep waters, seamounts and submarine canyons that are suitable for Gray''s beaked whales and their prey. We propose that the abundance of this rich habitat has promoted genetic homogeneity in this species. Furthermore, it has been suggested that the lack of beaked whale sightings is the result of their low abundance, but this is in contrast to our estimates of female effective population size based on mitochondrial data. In conclusion, the high diversity and lack of genetic structure can be explained by a historically large population size, in combination with no known exploitation, few apparent behavioural barriers and abundant habitat. 相似文献
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Holly B. Kramer Chun-Fui Lai Hetal Patel Manikandan Periyasamy Meng-Lay Lin Stephan M. Feller Frances V. Fuller-Pace David W. Meek Simak Ali Laki Buluwela 《Nucleic acids research》2016,44(2):582-594
Liver receptor homologue 1 (LRH-1) is an orphan nuclear receptor that has been implicated in the progression of breast, pancreatic and colorectal cancer (CRC). To determine mechanisms underlying growth promotion by LRH-1 in CRC, we undertook global expression profiling following siRNA-mediated LRH-1 knockdown in HCT116 cells, which require LRH-1 for growth and in HT29 cells, in which LRH-1 does not regulate growth. Interestingly, expression of the cell cycle inhibitor p21 (CDKN1A) was regulated by LRH-1 in HCT116 cells. p21 regulation was not observed in HT29 cells, where p53 is mutated. p53 dependence for the regulation of p21 by LRH-1 was confirmed by p53 knockdown with siRNA, while LRH-1-regulation of p21 was not evident in HCT116 cells where p53 had been deleted. We demonstrate that LRH-1-mediated p21 regulation in HCT116 cells does not involve altered p53 protein or phosphorylation, and we show that LRH-1 inhibits p53 recruitment to the p21 promoter, likely through a mechanism involving chromatin remodelling. Our study suggests an important role for LRH-1 in the growth of CRC cells that retain wild-type p53. 相似文献
948.
Anas M. Alazami Sarah M. Al-Qattan Eissa Faqeih Amal Alhashem Muneera Alshammari Fatema Alzahrani Mohammed S. Al-Dosari Nisha Patel Afaf Alsagheir Bassam Binabbas Hamad Alzaidan Abdulmonem Alsiddiky Nasser Alharbi Majid Alfadhel Amal Kentab Riza M. Daza Martin Kircher Jay Shendure Mais Hashem Saif Alshahrani Zuhair Rahbeeni Ola Khalifa Ranad Shaheen Fowzan S. Alkuraya 《Human genetics》2016,135(5):525-540
949.
Purvi M. Rakhashiya Pooja P. Patel Bhavisha P. Sheth Jigna G. Tank 《Archives Of Phytopathology And Plant Protection》2016,49(1-4):64-73
Plant pathogenic organisms are known to infect host cell using various range of secretory proteins. Amongst all other secretion systems, type III secretion system (T3SS) is a key mechanism for bacterial pathogenesis for establishing and maintaining infection into the host. Expression levels of seven genes viz. avrXacE1, avrXacE2, hpaA and hrpG along with bacterial endogenous control lrp (leucine-responsive protein) were studied. The pathogenic organisms selected for the present study includes Enterobacter cloacae, Enterobacter spp., Pantoea ananatis, Xanthomonas campestris pv. Citri, Pantoea agglomerans, Ochrobactrum anthropi and Erwinia chrysanthemi. P. agglomerans and Enterobacter spp. gave high expression of above-mentioned virulence genes compared to Xanthomonas, while E. cloacae and P. ananatis showed similar expression with that of Xanthomonas. The detailed relationship of the expression profiles with respect to the selected organisms is discussed. 相似文献
950.
Phycobiliproteins and phytochromes are light-harvesting and light-sensing proteins containing linear tetrapyrroles, so-called bile chromophores. The chromophores in certain biliproteins, including the phytochromes, isomerize reversibly from a stable Z-configuration to a stable E-configuration when irradiated with light of the appropriate wavelength. Here, we report the crystal structure of alpha-phycoerythrocyanin with its chromophore in the E-configuration, compare it with the Z-configuration found in trimeric phycoerythrocyanin, and reveal the structural bases of the isomerization. The geometric changes of the chromophore account for the large spectral shift, which characterizes the overall transition. Interactions of the chromophore A and D pyrrole rings with flexible protein moieties are required for the formation and stabilization of the isomers. We predict that the results will hold for all photoactive biliproteins. 相似文献