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981.
Skovierová H Larrouy-Maumus G Pham H Belanová M Barilone N Dasgupta A Mikusová K Gicquel B Gilleron M Brennan PJ Puzo G Nigou J Jackson M 《The Journal of biological chemistry》2010,285(53):41348-41355
The arabinogalactan (AG) of slow growing pathogenic Mycobacterium spp. is characterized by the presence of galactosamine (GalN) modifying some of the interior branched arabinosyl residues. The biosynthetic origin of this substituent and its role(s) in the physiology and/or pathogenicity of mycobacteria are not known. We report on the discovery of a polyprenyl-phospho-N-acetylgalactosaminyl synthase (PpgS) and the glycosyltransferase Rv3779 from Mycobacterium tuberculosis required, respectively, for providing and transferring the GalN substrate for the modification of AG. Disruption of either ppgS (Rv3631) or Rv3779 totally abolished the synthesis of the GalN substituent of AG in M. tuberculosis H37Rv. Conversely, expression of ppgS in Mycobacterium smegmatis conferred upon this species otherwise devoid of ppgS ortholog and any detectable polyprenyl-phospho-N-acetylgalactosaminyl synthase activity the ability to synthesize polyprenyl-phospho-N-acetylgalactosamine (polyprenyl-P-GalNAc) from polyprenyl-P and UDP-GalNAc. Interestingly, this catalytic activity was increased 40-50-fold by co-expressing Rv3632, the encoding gene of a small membrane protein apparently co-transcribed with ppgS in M. tuberculosis H37Rv. The discovery of this novel lipid-linked sugar donor and the involvement of a the glycosyltransferase C-type glycosyltransferase in its transfer onto its final acceptor suggest that pathogenic mycobacteria modify AG on the periplasmic side of the plasma membrane. The availability of a ppgS knock-out mutant of M. tuberculosis provides unique opportunities to investigate the physiological function of the GalN substituent and the potential impact it may have on host-pathogen interactions. 相似文献
982.
Hung Quoc Pham Anh Tuong Nguyen Mao Dinh Nguyen Augustine Arukwe 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2010,155(2):223-230
In the present study, we have investigated the sex steroid hormone levels, oocyte maturation and spawning performance in Waigieu seaperch (Psammoperca waigiensis) exposed to different doses (0, (control), 0.05, 0.25 and 0.5 mg/kg fish) of thyroxin (T4) both through diet (continuously) and injection (single injection). In addition, we also studied plasma steroid hormone levels and spawning performances in female fish injected with a single dose of D-Ala6, Pro9-Net-mGnRH (LHRHa: 50 µg/kg), human chronic gonadotropin (HCG: 1,500 IU/kg) and carp pituitary extract (CPE: 10 mg/kg). In all experiments, samples were collected at 0, 6, 12, 24 and 48 h after exposure. T4 exposure via dietary route produced differential and enhanced effects, compared with when the compound was injected to the broodstock. A significant association between exposure to dietary T4, elevated plasma steroid hormone levels, maturation-, spawning-, fertilization- and hatching rate, egg diameter, embryogenesis and larval growth were observed. Interestingly, we observed that broodstock groups fed with T4 doses spawned 20 days earlier than the control group. Thus, we propose that these differences may be attributed to higher systemic availability of T4 due to dietary exposure that is easily transferable to eggs and embryos, as opposed to injection that require absorption to increase bioavailability. Furthermore, our results show that LHRHa, CPE and HCG produced significant increase in spawning rate, but significantly reduced fertilization- and hatching rates. Waigieu seaperch is a new candidate for marine aquaculture in Vietnam and relatively little is known about the reproductive biology and endocrinology of this species. Therefore, the present study forms an integral basis for understanding the reproductive endocrinology of a tropical marine finfish with increasing aquaculture prospects and may also contribute in the development of sustainable aquaculture of this species in a developing country such as Vietnam. 相似文献
983.
Sumathy Babitha Dung H. Nguyen Sang-Joo Park Jeong-Hyun Shin Gaudelia A. Reyes Adeltrudes Caburian Eun-Ki Kim 《Biotechnology and Bioprocess Engineering》2010,15(6):1071-1076
In vitiligo, active melanocytes in the epidermis are not present, whereas melanoblast cells in the outer root sheath of hair
follicles are not affected. The existence of these inactive melanocytes provides a source for repigmentation of vitiligo.
To evaluate the potential of herbal candidates in treatment of vitiligo, we studied the effect of Cassia alata leaf extract on the differentiation, proliferation and migration of melanoblast cells. Melanin content increased in melb-a
melanoblast cells in response to this herb extract in a dose-dependent manner compared to control cells. In addition, it induced
tyrosinase activity and altered melb-a cell morphology. A transwell migration assay showed the potential of this herbal candidate
to induce direct migration of treated cells. To our knowledge, this is the first report on activity of this kind in Cassia alata. The findings of the present study are significant in the direction of developing safer strategies for vitiligo treatment. 相似文献
984.
985.
Haya Abu Ghazaleh Renfred S. Chow Sheryl L. Choo Diana Pham Jamie D. Olesen Russell X. Wong Christina Onyskiw Shairaz Baksh 《Apoptosis : an international journal on programmed cell death》2010,15(2):117-127
Death receptor-dependent apoptosis is an important mechanism of growth control. It has been demonstrated that Ras association domain family protein 1A (RASSF1A) is a tumor suppressor protein involved in death receptor-dependent apoptosis. However, it is unclear how RASSF1A-mediated cell death is initiated. We have now detailed 14-3-3 dependent regulation of RASSF1A-mediated cell death. We demonstrate that basal association of RASSF1A with 14-3-3 was lost following stimulation with tumor necrosis factor alpha (TNFα) or TNFα related apoptosis inducing ligand (TRAIL). Subsequent to the loss of 14-3-3 association, RASSF1A associated with modulator of apoptosis (MOAP-1) followed by death receptor association with either TNFα receptor 1 (TNF-R1) or TRAIL receptor 1 (TRAIL-R1). 14-3-3 association required basal phosphorylation by the serine/threonine kinase, glycogen synthase kinase 3β (GSK-3β), on serine 175, 178, and 179. Mutation of these critical serines resulted in the loss of 14-3-3 association and earlier recruitment of RASSF1A to MOAP-1, TNF-R1, and TRAIL-R1. Furthermore, stable cells containing a triple serine mutant of RASSF1A [serine (S) 175 to alanine (A) [S175A], S178A, and S179A] resulted in increased basal cell death, enhanced Annexin V staining and enhanced cleavage of poly (ADP-ribose) polymerase (PARP) following TNFα stimulation when compared to stable cells containing wild type RASSF1A. RASSF1A-mediated cell death is, therefore, tightly controlled by 14-3-3 association. 相似文献
986.
Eric D. Jensen Lan Pham Charles J. Billington Jr Kelly Espe Ann E. Carlson Jennifer J. Westendorf Anna Petryk Rajaram Gopalakrishnan Kim Mansky 《Journal of cellular biochemistry》2010,109(4):672-682
Previous studies found that bone morphogenic proteins (BMPs) support osteoclast formation, but it is not clear whether this is a direct effect on osteoclasts or mediated indirectly through osteoblasts. We have shown that a mouse deficient for the BMP antagonist Twisted gastrulation suggested a direct positive role for BMPs on osteoclastogenesis. In this report, we further determine the significance of BMP signaling on osteoclast formation in vitro. We find that BMP2 synergizes with suboptimal levels of receptor activator of NF‐κB ligand (RANKL) to enhance in vitro differentiation of osteoclast‐like cells. The enhancement by BMP2 is not a result of changes in the rate of proliferation or survival of the bone marrow‐derived cultures, but is accompanied by an increase in expression of genes involved in osteoclast differentiation and fusion. Treatment with BMP2 did not significantly alter expression of RANKL or OPG in our osteoclast cultures, suggesting that the enhancement of osteoclastogenesis is not mediated indirectly through osteoblasts or stromal cells. Consistent with this, we detected phosphorylated SMAD1,5,8 (p‐SMAD) in the nuclei of mononuclear and multinucleated cells in osteoclast cultures. Levels of p‐SMAD, BMP2, and BMP receptors increased during differentiation. RNAi suppression of Type II BMP receptor inhibited RANKL‐stimulated formation of multinuclear TRAP‐positive cells. The BMP antagonist noggin inhibited RANKL‐mediated osteoclast differentiation when added prior to day 3, while addition of noggin on day 3 or later failed to inhibit their differentiation. Taken together, these data indicate that osteoclasts express BMP2 and BMP receptors, and that autocrine BMP signaling directly promotes the differentiation of osteoclasts‐like cells. J. Cell. Biochem. 109: 672–682, 2010. © 2009 Wiley‐Liss, Inc. 相似文献
987.
Baolei Jia Sangmin Lee Bang P. Pham Yoon Seung Cho Jae-Kyung Yang Hee-Seop Byeon Jong Cheol Kim Gang-Won Cheong 《Molecules and cells》2010,29(4):363-371
NADH oxidases (NOXs) catalyze the two-electron reduction of oxygen to H2O2 or four-electron reduction of oxygen to H2O. In this report, we show that an NADH oxidase from Thermococcus profundus (NOXtp) displays two forms: a native dimeric protein under physiological conditions and an oxidized hexameric form under
oxidative stress. Native NOXtp displays high NADH oxidase activity, and oxidized NOXtp can accelerate the aggregation of partially
unfolded proteins. The aggregates formed by NOXtp have characteristics similar to β-amyloid and Lewy bodies in neurodegenerative
diseases, including an increase of β-sheet content. Oxidized NOXtp can also bind nucleic acids and cause their degradation
by oxidizing NADH to produce H2O2. Furthermore, Escherichia coli cells expressing NOXtp are less viable than cells not expressing NOXtp after treatment with H2O2. As NOXtp shares similar features with eukaryotic cell death isozymes and life may have originated from hyperthermophiles,
we suggest that NOXtp may be an ancestor of cell death proteins. 相似文献
988.
A. B. Imbs I. M. Yakovleva N. A. Latyshev L. Q. Pham 《Russian Journal of Marine Biology》2010,36(6):452-457
The fatty acid (FA) composition of zooxanthellae, polyp tissue, and intact colonies was determined in soft coral Sinularia sp. and hard coral Acropora sp. Analysis of the distribution of polyunsaturated fatty acids (PUFAs) among the zooxanthellae and the host organism showed
that 18: 3n-6 and C18–22 PUFAs of the n-3 series (18: 4n-3, 20: 5n-3, 22: 5n-3, and 22: 6n-3) were mainly synthesized by the zooxanthellae and that
C20–22 PUFAs of the n-6 series (20: 3n-6, 20: 4n-6, and 22: 4n-6) were synthesized in the polyp tissue. Soft coral polyps were able
to synthesize tetracosapolyenoic FAs (24: 5n-6 and 24: 6n-3) and 18: 2n-7, their zooxanthellae synthesized C16 PUFAs (16: 2n-7, 16: 3n-4, and 16: 4n-1). It is supposed that the biosynthesis of 16: 2n-7 in Sinularia sp. and 18: 3n-6 in Acropora sp. is catalyzed by Δ6 desaturase. The relatively even distribution of three FAs (18: 2n-6, 18: 3n-6, and 16: 2n-7) among
lipids of zooxanthellae and coral polyps indicates the possible transport of these FAs between symbionts and the host organism. 相似文献
989.
Wei Yao Weiwei Dai Mohammad Shahnazari Aaron Pham Zhiqiang Chen Haiyan Chen Min Guan Nancy E. Lane 《PloS one》2010,5(7)
Augmentation of the peak bone mass (PBM) may be one of the most effective interventions to reduce the risk of developing osteoporosis later in life; however treatments to augment PBM are currently limited. Our study evaluated whether a greater PBM could be achieved either in the progesterone nuclear receptor knockout mice (PRKO) or by using a nuclear progesterone receptor (nPR) antagonist, RU486 in mice. Compared to their wild type (WT) littermates the female PRKO mice developed significantly higher cancellous and cortical mass in the distal femurs, and this was associated with increased bone formation. The high bone mass phenotype was partially reproduced by administering RU486 in female WT mice from 1–3 months of age. Our results suggest that the inhibition of the nPR during the rapid bone growth period (1–3 months) increases osteogenesis, which results in acquisition of higher bone mass. Our findings suggest a crucial role for progesterone signaling in bone acquisition and inhibition of the nPR as a novel approach to augment bone mass, which may have the potential to reduce the burden of osteoporosis. 相似文献
990.
Aude Aumeunier Fran?oise Grela Abdulraouf Ramadan Linh Pham Van Emilie Bardel Alejandro Gomez Alcala Pascale Jeannin Shizuo Akira Jean-Fran?ois Bach Nathalie Thieblemont 《PloS one》2010,5(7)