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Péterfy M, Phan J, Xu P, Reue K. Lipodystrophy in the fld mouse results from mutation of a new gene encoding a nuclear protein, lipin. Nat Genet 2001; 27:121-4. [PMID: 11138012 DOI: 10.1038/83685] [Citation(s) in RCA: 465] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Mice carrying mutations in the fatty liver dystrophy (fld) gene have features of human lipodystrophy, a genetically heterogeneous group of disorders characterized by loss of body fat, fatty liver, hypertriglyceridemia and insulin resistance. Through positional cloning, we have isolated the gene responsible and characterized two independent mutant alleles, fld and fld(2J). The gene (Lpin1) encodes a novel nuclear protein which we have named lipin. Consistent with the observed reduction of adipose tissue mass in fld and fld(2J)mice, wild-type Lpin1 mRNA is expressed at high levels in adipose tissue and is induced during differentiation of 3T3-L1 pre-adipocytes. Our results indicate that lipin is required for normal adipose tissue development, and provide a candidate gene for human lipodystrophy. Lipin defines a novel family of nuclear proteins containing at least three members in mammalian species, and homologs in distantly related organisms from human to yeast.
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Abstract
Water-soluble chitosan derivatives were prepared by graft copolymerization of maleic acid sodium onto hydroxypropyl chitosan and carboxymethyl chitosan sodium. Their scavenging activities against hydroxyl radical *OH were investigated by chemiluminescence technique. They exhibit IC(50) values ranging from 246 to 498 microg/mL, which should be attributed to their different contents of hydroxyl and amino groups and different substituting groups.
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Loane RF, Xu P, Silcox J. Thermal vibrations in convergent-beam electron diffraction. Acta Crystallogr A 1991. [DOI: 10.1107/s0108767391000375] [Citation(s) in RCA: 230] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Nei M, Xu P, Glazko G. Estimation of divergence times from multiprotein sequences for a few mammalian species and several distantly related organisms. Proc Natl Acad Sci U S A 2001; 98:2497-502. [PMID: 11226267 PMCID: PMC30166 DOI: 10.1073/pnas.051611498] [Citation(s) in RCA: 220] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/22/2000] [Indexed: 11/18/2022] Open
Abstract
When many protein sequences are available for estimating the time of divergence between two species, it is customary to estimate the time for each protein separately and then use the average for all proteins as the final estimate. However, it can be shown that this estimate generally has an upward bias, and that an unbiased estimate is obtained by using distances based on concatenated sequences. We have shown that two concatenation-based distances, i.e., average gamma distance weighted with sequence length (d(2)) and multiprotein gamma distance (d(3)), generally give more satisfactory results than other concatenation-based distances. Using these two distance measures for 104 protein sequences, we estimated the time of divergence between mice and rats to be approximately 33 million years ago. Similarly, the time of divergence between humans and rodents was estimated to be approximately 96 million years ago. We also investigated the dependency of time estimates on statistical methods and various assumptions made by using sequence data from eubacteria, protists, plants, fungi, and animals. Our best estimates of the times of divergence between eubacteria and eukaryotes, between protists and other eukaryotes, and between plants, fungi, and animals were 3, 1.7, and 1.3 billion years ago, respectively. However, estimates of ancient divergence times are subject to a substantial amount of error caused by uncertainty of the molecular clock, horizontal gene transfer, errors in sequence alignments, etc.
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Koop BF, Goodman M, Xu P, Chan K, Slightom JL. Primate eta-globin DNA sequences and man's place among the great apes. Nature 1986; 319:234-8. [PMID: 3945312 DOI: 10.1038/319234a0] [Citation(s) in RCA: 180] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Molecular studies indicate that chimpanzee and gorilla are the closest relatives of man (refs 1-7 and refs therein). The small molecular distances found point to late ancestral separations, with the most recent being between chimpanzee and man, as judged by DNA hybridization. Kluge and Schwartz contest these conclusions: morphological characters group a chimpanzee-gorilla clade with the Asian ape orang-utan in Kluge's cladistic study and with an orang-utan-human clade in Schwartz's study. Clearly, extensive sequencing of nuclear DNA is needed to resolve by cladistic analysis the branching order within Hominoidea. Towards this goal, we are sequencing orthologues of the primate psi eta-globin locus. Here, we compare the newly completed sequences of orang-utan and rhesus monkey with human, chimpanzee, gorilla, owl monkey, lemur and goat orthologues. Our findings substantially increase the evidence indicative of a human-chimpanzee-gorilla clade with ancestral separations around 8 to 6 Myr ago. We also verify that neutral hominoid DNA evolved at markedly retarded rates.
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Gebara OC, Mittleman MA, Sutherland P, Lipinska I, Matheney T, Xu P, Welty FK, Wilson PW, Levy D, Muller JE. Association between increased estrogen status and increased fibrinolytic potential in the Framingham Offspring Study. Circulation 1995; 91:1952-8. [PMID: 7895352 DOI: 10.1161/01.cir.91.7.1952] [Citation(s) in RCA: 165] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
BACKGROUND Although extensive evidence indicates that estrogen is responsible for the markedly decreased cardiovascular risk of premenopausal women, the mechanism through which estrogen might exert its protective effect has not been adequately explained. Since thrombosis is now recognized to play an important role in the onset of cardiovascular disease, we investigated the relation between estrogen status and fibrinolytic potential, a determinant of thrombotic risk. METHODS AND RESULTS We determined levels of plasminogen activator inhibitor (PAI-1) antigen and tissue plasminogen activator (TPA) antigen in 1431 subjects from the Framingham Offspring Study. Fibrinolytic potential was compared between subjects with high estrogen status (premenopausal women and postmenopausal women receiving hormone replacement therapy) and low estrogen status (men and postmenopausal women not receiving hormone replacement therapy). In all comparisons, subjects with high estrogen status had greater fibrinolytic potential (lower PAI-1 levels) than subjects with low estrogen status. First, postmenopausal women receiving estrogen replacement therapy had lower levels of PAI-1 than those not receiving therapy (13.0 +/- 0.5 versus 19.5 +/- 1.0 ng/mL, P < .001). Second, premenopausal women had lower levels of PAI-1 than men of a similar age (14.8 +/- 0.6 versus 20.3 +/- 0.8 ng/mL, P < .001); this sex difference diminished when postmenopausal women not receiving hormone replacement therapy were compared with men of a similar age (19.6 +/- 0.7 versus 21.1 +/- 0.7 ng/mL, P = .089). Third, premenopausal women had markedly lower levels of PAI-1 antigen than postmenopausal women not receiving estrogen therapy (14.8 +/- 0.6 versus 19.5 +/- 1.0 ng/mL, P < .001). The between-group differences observed for TPA antigen were similar to those for PAI-1 antigen. CONCLUSIONS Each of these comparisons indicates that the cardioprotective effect of estrogen may be mediated, in part, by an increase in fibrinolytic potential. These findings might provide at least a partial explanation for the protection against cardiovascular disease experienced by premenopausal women, and the loss of that protection following menopause.
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Xiao ZJ, Liu PH, Qin JY, Xu P. Statistical optimization of medium components for enhanced acetoin production from molasses and soybean meal hydrolysate. Appl Microbiol Biotechnol 2007; 74:61-8. [PMID: 17043817 DOI: 10.1007/s00253-006-0646-5] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2006] [Revised: 08/18/2006] [Accepted: 08/22/2006] [Indexed: 11/27/2022]
Abstract
The nutritional requirements for acetoin production by Bacillus subtilis CICC 10025 were optimized statistically in shake flask experiments using indigenous agroindustrial by-products. The medium components considered for initial screening in a Plackett-Burman design comprised a-molasses (molasses submitted to acidification pretreatment), soybean meal hydrolysate (SMH), KH(2)PO(4).3H(2)O, sodium acetate, MgSO(4).7H(2)O, FeCl(2), and MnCl(2), in which the first two were identified as significantly (at the 99% significant level) influencing acetoin production. Response surface methodology was applied to determine the mutual interactions between these two components and optimal levels for acetoin production. In flask fermentations, 37.9 g l(-1) acetoin was repeatedly achieved using the optimized concentrations of a-molasses and SMH [22.0% (v/v) and 27.8% (v/v), respectively]. a-Molasses and SMH were demonstrated to be more productive than pure sucrose and yeast extract plus peptone, respectively, in acetoin fermentation. In a 5-l fermenter, 35.4 g l(-1) of acetoin could be obtained after 56.4 h of cultivation. To our knowledge, these results, i.e., acetoin yields in flask or fermenter fermentations, were new records on acetoin fermentation by B. subtilis.
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Evaluation Study |
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Chen X, Zhang DJ, Qi WT, Gao SJ, Xiu ZL, Xu P. Microbial fed-batch production of 1,3-propanediol by Klebsiella pneumoniae under micro-aerobic conditions. Appl Microbiol Biotechnol 2003; 63:143-6. [PMID: 12908084 DOI: 10.1007/s00253-003-1369-5] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2003] [Revised: 05/13/2003] [Accepted: 05/16/2003] [Indexed: 11/22/2022]
Abstract
The microbial production of 1,3-propanediol (1,3-PD) by Klebsiella pneumoniae under micro-aerobic conditions was investigated in this study. The experimental results of batch fermentation showed that the final concentration and yield of 1,3-PD on glycerol under micro-aerobic conditions approached values achieved under anaerobic conditions. However, less ethanol was produced under microaerobic than anaerobic conditions at the end of fermentation. The batch micro-aerobic fermentation time was markedly shorter than that of anaerobic fermentation. This led to an increment of productivity of 1,3-PD. For instance, the concentration, molar yield, and productivity of 1,3-PD of batch micro-aerobic fermentation by K. pneumoniae DSM 2026 were 17.65 g/l, 56.13%, and 2.94 g l(-1) h(-1), respectively, with a fermentation time of 6 h and an initial glycerol concentration of 40 g/l. Compared with DSM 2026, the microbial growth of K. pneumoniae AS 1.1736 was slow and the concentration of 1,3-PD was low under the same conditions. Furthermore, the microbial growth in fed-batch fermentation by K. pneumoniae DSM 2026 was faster under micro-aerobic than anaerobic conditions. The concentration, molar yield, and productivity of 1,3-PD in fed-batch fermentation under micro-aerobic conditions were 59.50 g/l, 51.75%, and 1.57 g l(-1) h(-1), respectively. The volumetric productivity of 1,3-PD under microaerobic conditions was almost twice that of anaerobic fed-batch fermentation, at 1.57 and 0.80 g l(-1) h(-1), respectively.
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Hu FY, Tao DY, Sacks E, Fu BY, Xu P, Li J, Yang Y, McNally K, Khush GS, Paterson AH, Li ZK. Convergent evolution of perenniality in rice and sorghum. Proc Natl Acad Sci U S A 2003; 100:4050-4. [PMID: 12642667 PMCID: PMC153046 DOI: 10.1073/pnas.0630531100] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Annual and perennial habit are two major strategies by which grasses adapt to seasonal environmental change, and these distinguish cultivated cereals from their wild relatives. Rhizomatousness, a key trait contributing to perenniality, was investigated by using an F(2) population from a cross between cultivated rice (Oryza sativa) and its wild relative, Oryza longistaminata. Molecular mapping based on a complete simple sequence-repeat map revealed two dominant-complementary genes controlling rhizomatousness. Rhz3 was mapped to the interval between markers OSR16 [1.3 centimorgans (cM)] and OSR13 (8.1 cM) on rice chromosome 4 and Rhz2 located between RM119 (2.2 cM) and RM273 (7.4 cM) on chromosome 3. Comparative mapping indicated that each gene closely corresponds to major quantitative trait loci (QTLs) controlling rhizomatousness in Sorghum propinquum, a wild relative of cultivated sorghum. Correspondence of these genes in rice and sorghum, which diverged from a common ancestor approximately 50 million years ago, suggests that the two genes may be key regulators of rhizome development in many Poaceae. Many additional QTLs affecting abundance of rhizomes in O. longistaminata were identified, most of which also corresponded to the locations of S. propinquum QTLs. Convergent evolution of independent mutations at, in some cases, corresponding genes may have been responsible for the evolution of annual cereals from perennial wild grasses. DNA markers closely linked to Rhz2 and Rhz3 will facilitate cloning of the genes, which may contribute significantly to our understanding of grass evolution, advance opportunities to develop perennial cereals, and offer insights into environmentally benign weed-control strategies.
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Xu P, Wang YL, Zhu SJ, Luo SY, Piao YS, Zhuang LZ. Expression of matrix metalloproteinase-2, -9, and -14, tissue inhibitors of metalloproteinase-1, and matrix proteins in human placenta during the first trimester. Biol Reprod 2000; 62:988-94. [PMID: 10727268 DOI: 10.1095/biolreprod62.4.988] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Matrix metalloproteinases (MMPs) are implicated in the degradation of extracellular matrix; they play important roles in the invasion of the trophoblast cell into the maternal endometrium during placentation. Previous studies have concentrated on comparison of MMP expression in trophoblast cells between the first and third trimester. But the dynamic expression of MMPs during the first trimester has not been reported. In the present study, the expression of MMP-2, -9, and -14 (membrane-type MMP-1) and the production of tissue inhibitors of metalloproteinases (TIMP-1 and TIMP-2) by cultured human cytotrophoblast cells from 6 to 11 wk of gestation were investigated. The cells were cultured under serum-free conditions. There was no MMP-9 secretion by the cells at Week 6, but from Week 7 to 11 the MMP-9 secretion increased gradually. Week 11 cells secreted more than 10-fold as much MMP-9 (167.7 +/- 18.8 ng/ml) as Week 7 (14.7 +/- 3.9 ng/ml) cultures. However, MMP-2 production declined from Week 6 to Week 11, and the production at Week 11 (32.3 +/- 8.1 ng/ml) was about one sixth that at Week 6 (205.7 +/- 27.2 ng/ml). The expression of mRNA transcripts for MMP-2 and MMP-9 correlated with enzyme secretion; we did not detect any MMP-9 mRNA signal in 20 microg total RNA extracted from cultured cells at Weeks 6, 7, and 8 of pregnancy, but a signal was apparent in Weeks 9 and 11. MMP-2 mRNA was expressed throughout the 6- to 11-wk period and exhibited a remarkable decline during this period. MMP-14 mRNA transcripts remained relatively stable from 6 to 11 wk. Significantly more TIMP-1 (P < 0.01) was detected in Week 9 (87.5 +/- 15.0 ng/ml) and Week 11 (169.1 +/- 30.2 ng/ml) media compared to Week 6 media (23.5 +/- 4.8 ng/ml), but we did not detect any TIMP-2 in the media of the tested cells. This study demonstrated that first-trimester human cytotrophoblast cells were able to produce abundant laminin, fibronectin, and vitronectin. However, we did not observe detectable secretion of collagen I and collagen IV. These data indicated that human trophoblast-derived MMPs and their inhibitors are intrinsically and developmentally regulated. The same cytotrophoblast cells that produced MMPs could also secrete various substrates for these enzymes.
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Sun B, Xu P, Salvaterra PM. Dynamic visualization of nervous system in live Drosophila. Proc Natl Acad Sci U S A 1999; 96:10438-43. [PMID: 10468627 PMCID: PMC17907 DOI: 10.1073/pnas.96.18.10438] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We have constructed transgenic Drosophila melanogaster lines that express green fluorescent protein (GFP) exclusively in the nervous system. Expression is controlled with transcriptional regulatory elements present in the 5' flanking DNA of the Drosophila Na(+), K(+)-ATPase beta-subunit gene Nervana2 (Nrv2). This regulatory DNA is fused to the yeast transcriptional activator GAL4, which binds specifically to a sequence motif termed the UAS (upstream activating sequence). Drosophila lines carrying Nrv2-GAL4 transgenes have been genetically recombined with UAS-GFP (S65T) transgenes (Nrv2-GAL4+UAS-GFP) inserted on the same chromosomes. We observe strong nervous system-specific fluorescence in embryos, larvae, pupae, and adults. The GFP fluorescence is sufficiently bright to allow dynamic imaging of the nervous system at all of these developmental stages directly through the cuticle of live Drosophila. These lines provide an unprecedented view of the nervous system in living animals and will be valuable tools for investigating a number of developmental, physiological, and genetic neurobiological problems.
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Widmer G, Akiyoshi D, Buckholt MA, Feng X, Rich SM, Deary KM, Bowman CA, Xu P, Wang Y, Wang X, Buck GA, Tzipori S. Animal propagation and genomic survey of a genotype 1 isolate of Cryptosporidium parvum. Mol Biochem Parasitol 2000; 108:187-97. [PMID: 10838221 DOI: 10.1016/s0166-6851(00)00211-5] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Human cryptosporidiosis is attributed to two major Cryptosporidium parvum genotypes of which type 1 appears to be the predominant. Most laboratory investigations however are performed using genotype 2 isolates, the only type which readily infects laboratory animals. So far type 1 has only been identified in humans and primates. A type 1 isolate, obtained from an individual with HIV and cryptosporidiosis, was successfully adapted to propagate in gnotobiotic piglets. Genotypic characterization of oocyst DNA from this isolate using multiple restriction fragment length polymorphisms, a genotype-specific PCR marker, and direct sequence analysis of two polymorphic loci confirmed that this isolate, designated NEMC1, is indeed type 1. No changes in the genetic profile were identified during multiple passages in piglets. In contrast, the time period between infection and onset of fecal oocyst shedding, an indicator of adaptation, decreased with increasing number of passages. Consistent with other type 1 isolates, NEMC1 failed to infect mice. A preliminary survey of the NEMC1 genome covering approximately 2% of the genome and encompassing 200 kb of unique sequence showed an average similarity of approximately 95% between type 1 and 2 sequences. Twenty-four percent of the NEMC1 sequences were homologous to previously determined genotype 2 C. parvum sequences. To our knowledge, this is the first successful serial propagation of genotype 1 in animals, which should facilitate characterization of the unique features of this human pathogen.
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Xu P, Huecksteadt TP, Hoidal JR. Molecular cloning and characterization of the human xanthine dehydrogenase gene (XDH). Genomics 1996; 34:173-80. [PMID: 8661045 DOI: 10.1006/geno.1996.0262] [Citation(s) in RCA: 80] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Xanthine dehydrogenase (XDH, EC 1.1.1.204) is a rate-limiting enzyme in the oxidative metabolism of purines and is thought to play a key role in a variety of pathophysiologic processes including ischemiasolidusreperfusion injury, viral pneumonia, and renal failure. We herein report the isolation and characterization of the human XDH gene. The gene is composed of 36 exons and 35 introns and spans at least 60 kb. The exon sizes range from 53 to 279 bp, and the intron sizes range from 0.2 to over 8 kb. Using primer extension and RNase protection analyses, two transcriptional initiation sites were identified 59 and 82 nucleotides upstream of the ATG start codon. One Goldberg-Hogness box (ATTTAT)-like sequence was found 24 bp upstream from the second transcriptional initiation site, and two inverted CCAAT sequences were found 19 and 42 bp upstream from the second transcriptional initiation sites. A relative GC-enriched region was found between -55 and -121. Approximately 2 kb of the 5'-flanking region was sequenced, and a variety of putative regulatory elements were identified including CsolidusEBP binding sites, IL-6 and NF-kappaB sites, and potential TNF-RE, IFN-gamma-RE, and IL-1-RE sites.
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Jin H, Liu FM, Xu P, Xia JL, Zhong ML, Yuan Y, Zhou JW, Gong YX, Wang W, Zhu SN. On-chip generation and manipulation of entangled photons based on reconfigurable lithium-niobate waveguide circuits. PHYSICAL REVIEW LETTERS 2014; 113:103601. [PMID: 25238358 DOI: 10.1103/physrevlett.113.103601] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Indexed: 05/14/2023]
Abstract
A consequent tendency toward high-performance quantum information processing is to develop the fully integrated photonic chip. Here, we report the on-chip generation and manipulation of entangled photons based on reconfigurable lithium-niobate waveguide circuits. By introducing a periodically poled structure into the waveguide circuits, two individual photon-pair sources with a controllable electro-optic phase shift are produced within a Hong-Ou-Mandel interferometer, resulting in a deterministically separated identical photon pair. The state is characterized by 92.9±0.9% visibility Hong-Ou-Mandel interference. The photon flux reaches ∼1.4×10(7) pairs nm-1 mW-1. The whole chip is designed to contain nine similar units to produce identical photon pairs spanning the telecom C and L band by the flexible engineering of nonlinearity. Our work presents a scenario for on-chip engineering of different photon sources and paves the way to fully integrated quantum technologies.
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Blackledge MJ, Brüschweiler R, Griesinger C, Schmidt JM, Xu P, Ernst RR. Conformational backbone dynamics of the cyclic decapeptide antamanide. Application of a new multiconformational search algorithm based on NMR data. Biochemistry 1993; 32:10960-74. [PMID: 8218162 DOI: 10.1021/bi00092a005] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
A general procedure for the analysis of biomolecular structures by NMR in the presence of rapid conformational dynamics has been applied to the study of the cyclic decapeptide antamanide. Two-dimensional experiments, relaxation measurements in the rotating frame, and homo- and heteronuclear coupling constant determinations have been used to characterize the dynamic properties of the molecule, in combination with a novel search algorithm for investigating multiconformational equilibria. Direct evidence for the presence of a conformational exchange process with an activation energy of approximately 20 kJ mol-1 and an exchange lifetime of approximately 25 microseconds at 320 K has been obtained from rotating frame relaxation measurements. This evidence is combined with the information derived from the multiconformational search algorithm MEDUSA to propose sets of structures that coexist in a dynamic exchange equilibrium.
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Yuan QL, Yang CX, Xu P, Gao XQ, Deng L, Chen P, Sun ZL, Chen QY. Neuroprotective effects of ginsenoside Rb1 on transient cerebral ischemia in rats. Brain Res 2007; 1167:1-12. [PMID: 17663984 DOI: 10.1016/j.brainres.2007.06.024] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2007] [Revised: 05/28/2007] [Accepted: 06/03/2007] [Indexed: 02/05/2023]
Abstract
Previous experiments showed that ginsenoside Rb1 (GRb1) reduced infarct and neuronal deficit in rats followed by transient cerebral ischemia. The mechanism of this neuroprotective function is unclear. Here, we tested whether the effect of GRb1 can be achieved through preventing ischemic neuronal death, modulating apoptotic-related genes and affecting glial-derived neurotrophic factor (GDNF) expression in rats subjected to occlusion of the middle cerebral artery. When GRb1(40 mg/kg, i.p.) was administered immediately after reperfusion, the apoptotic cells in the GRb1 group were decreased significantly from 12 to 72 h of reperfusion compared to the ischemia group by TdT-mediated dUTP-biotin nick-end labeling. Immunostaining and Western blotting analysis showed that the expression of GDNF from 3 to 120 h of the GRb1 group was significantly increased compared to the ischemia group, and GDNF expression peaked at 48 h after reperfusion. The enhanced GDNF mRNA in the GRb1 group was not detected by RT-PCR and in situ hybridization compared to the ischemia group, but GDNF mRNA at 48 h after reperfusion was strongly increased in both the ischemia and GRb1 group when compared to other time points. The number of bcl-2-positive cells was significantly increased from 12 to 120 h of reperfusion compared to the ischemia group. However, the number of bax-positive cells in the GRb1 group was significantly declined compared to the ischemia group. In the GRb1 group, the number of neuronal apoptosis inhibitory protein-positive cells from 12 to 120 h after reperfusion was evidently higher than that in the ischemia group. Therefore, ginsenoside Rb1 prevents ischemic neuronal death induced by transient cerebral ischemia, and this mechanism of which is related to increase the expression of the antiapoptotic genes and modulate the expression of GDNF.
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Liu JT, Guo X, Ma WJ, Zhang YG, Xu P, Yao JF, Bai YD. Mitochondrial function is altered in articular chondrocytes of an endemic osteoarthritis, Kashin-Beck disease. Osteoarthritis Cartilage 2010; 18:1218-26. [PMID: 20650322 DOI: 10.1016/j.joca.2010.07.003] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2010] [Revised: 07/08/2010] [Accepted: 07/14/2010] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Kashin-Beck disease (KBD) is an endemic degenerative osteoarthritis (OA) associated with extracellular matrix degradation and chondrocyte necrosis in the articular and growth plate cartilage. The role of mitochondria in degenerative diseases is widely recognized but its function in KBD is unknown. The aim of this investigation was to evaluate mitochondrial function to understand the mitochondria-mediated caspase activation and apoptosis in adult KBD chondrocytes. METHODS Mitochondrial function was evaluated by analyzing the activities of respiratory chain enzyme complexes and citrate synthase (CS), intracellular adenosine triphosphate (ATP) contents, as well as changes in mitochondrial membrane potential (DeltaPsim). Apoptotic cell death was evaluated by analyzing the cytochrome c release from mitochondria to the cytosol, caspase-9 and 3 activities, and the apoptosis rate of KBD articular chondrocytes. RESULTS Activities of complexes II, III, IV and V were reduced in KBD articular chondrocytes compared with cells from normal controls. However, the mitochondrial mass was increased in KBD samples. Cultured KBD chondrocytes had a reduction of cellular ATP levels and contained a higher proportion of cells with de-energized mitochondria. Mitochondrial cytochrome c release and activation of caspase-9 and 3 were also observed. The percentages of positive apoptotic chondrocytes from the KBD patient group stained by Hoechst nuclear stain and Annexin V/PI for flow cytometry exhibited higher levels than that of the healthy controls. CONCLUSION These findings suggest the involvement of mitochondrial function and apoptotic cell death in the pathophysiology of KBD. The dysfunction of the mitochondria may play an important role in KBD articular chondrocytes apoptosis.
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Xu P, Wang S, Liu L, Peatman E, Somridhivej B, Thimmapuram J, Gong G, Liu Z. Channel catfish BAC-end sequences for marker development and assessment of syntenic conservation with other fish species. Anim Genet 2006; 37:321-6. [PMID: 16879340 DOI: 10.1111/j.1365-2052.2006.01453.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In the present study, 25 195 BAC ends for channel catfish (Ictalurus punctatus) were sequenced, generating 20 366 clean BAC-end sequences (BES), with an average read length of 557 bp after trimming. A total of 11 414 601 bp were generated, representing approximately 1.2% of the catfish genome. Based on this survey, the catfish genome was found to be highly AT-rich, with 60.7% A+T and 39.3% G+C. Approximately 12% of the catfish genome consisted of dispersed repetitive elements, with the Tc1/mariner transposons making up the largest percentage by base pair (4.57%). Microsatellites were detected in 17.5% of BES. Catfish BACs were anchored to the zebrafish and Tetraodon genome sequences by BLASTN, generating 16% and 8.2% significant hits (E < e(-5)) respectively. A total of 1074 and 773 significant hits were unique to the zebrafish and Tetraodon genomes, respectively, of which 417 and 406, respectively, were identified as known genes in other species, providing a major genome resource for comparative genomic mapping.
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Wu Q, Yang ZP, Xu P, Gao LC, Fan DM. Association between Helicobacter pylori infection and the risk of colorectal neoplasia: a systematic review and meta-analysis. Colorectal Dis 2013; 15:e352-64. [PMID: 23672575 DOI: 10.1111/codi.12284] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2012] [Accepted: 02/05/2013] [Indexed: 12/12/2022]
Abstract
AIM The existing evidence on the relationship between Helicobacter pylori infection and the risk of colorectal neoplasia is inconsistent. We conducted a systematic review with a meta-analysis to explore this relationship and to determine whether the relationship varies according to the study characteristics. METHOD We searched the PubMed database and the reference lists of pertinent articles published up to July 2012. Summary odds ratios (ORs) with their 95% confidence intervals (CIs) were estimated using a random-effects model. RESULTS Twenty-seven studies including 3792 cases of colorectal adenoma (CRA) and 3488 cases of colorectal cancer (CRC) were identified. Overall, H. pylori infection was associated with an increased risk of CRA (OR = 1.66, 95% CI 1.39-1.97, I(2) = 54.3%) and CRC (OR = 1.39, 95% CI 1.18-1.64, I(2) = 35.8%), although there was significant heterogeneity among the studies. Subgroup analysis revealed that the positive correlation did not differ by sex, geographic variation or subsite of neoplasia, but might vary by the method of detection of H. pylori. The study was underpowered to determine the risk of colorectal neoplasia associated with cytotoxin-associated gene A-positive H. pylori. CONCLUSION This meta-analysis demonstrates a positive association between H. pylori infection and the risk of colorectal neoplasia.
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Meta-Analysis |
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Xu P, Neek-Amal M, Barber SD, Schoelz JK, Ackerman ML, Thibado PM, Sadeghi A, Peeters FM. Unusual ultra-low-frequency fluctuations in freestanding graphene. Nat Commun 2014; 5:3720. [DOI: 10.1038/ncomms4720] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 03/26/2014] [Indexed: 11/09/2022] Open
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Fan L, Zhang W, Guo D, Tan ZR, Xu P, Li Q, Liu YZ, Zhang L, He TY, Hu DL, Wang D, Zhou HH. The Effect of Herbal Medicine Baicalin on Pharmacokinetics of Rosuvastatin, Substrate of Organic Anion-transporting Polypeptide 1B1. Clin Pharmacol Ther 2007; 83:471-6. [PMID: 17851565 DOI: 10.1038/sj.clpt.6100318] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The aim of this study was to explore potential herb-drug interaction between baicalin and rosuvastatin, a typical substrate for organic anion-transporting polypeptide 1B1 (OATP1B1) related to different OATP1B1 haplotype groups. Eighteen unrelated healthy volunteers who were CYP2C9*1/*1 with different OATP1B1 haplotypes (six OATP1B1*1b/*1b, six OATP1B1*1b/*15, and six OATP1B1*15/*15) were selected to participate in this study. Rosuvastatin (20 mg orally) pharmacokinetics after coadministration of placebo and 50-mg baicalin tablets (three times daily orally for 14 days) were measured for up to 72 h by liquid chromatography-mass spectrometry in a two-phase randomized crossover study. After baicalin treatment, the area under the plasma concentration-time curve (AUC)(0-72) and AUC(0-infinity) of rosuvastatin decreased by 47.0+/-11.0% (P=0.001) and 41.9+/-7.19% (P=0.001) in OATP1B1*1b/*1b, 21.0+/-20.6% (P=0.035) and 23.9+/-8.66% (P=0.004) in OATP1B1*1b/*15, and 9.20+/-11.6% (P=0.077) and 1.76+/-4.89% (P=0.36) in OATP1B1*15/*15, respectively. Moreover, decreases of both AUC(0-72) and AUC(0-infinity) of rosuvastatin among different haplotype groups were significantly different (P=0.002 and <0.001). Baicalin reduces plasma concentrations of rosuvastatin in an OATP1B1 haplotype-dependent manner.
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Xu P, Wang Y, Piao Y, Bai S, Xiao Z, Jia Y, Luo S, Zhuang L. Effects of matrix proteins on the expression of matrix metalloproteinase-2, -9, and -14 and tissue inhibitors of metalloproteinases in human cytotrophoblast cells during the first trimester. Biol Reprod 2001; 65:240-6. [PMID: 11420245 DOI: 10.1095/biolreprod65.1.240] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
The activity of matrix metalloproteinases (MMPs) specifies the ability of the trophoblast cell to degrade extracellular matrix (ECM) substrates. Usually the process of normal human placentation involves a coordinated interaction between the fetal-derived trophoblast cells and their microenvironment in the uterus. In this study, the effects of ECM proteins on the expression of MMP-2, -9, and -14 (membrane-type MMP-1); and the production of tissue inhibitors of metalloproteinase (TIMP) types -1, -2, and -3 have been investigated. Cytotrophoblast cells at 9 or 10 wk of gestation were cultured on various ECM coated dishes under serum-free conditions. Gelatin zymography analysis showed that cells grown on fibronectin (FN), laminin (LN), and vitronectin (VN) secreted more MMP-9 (about 1.5- to 3-fold more) than cells cultured on collagen I (Col I), whereas the secretion of MMP-9 by cells cultured on collagen IV (Col IV) was only half that by the cells on Col I. Northern Blot analysis gave the same results as zymography, indicating that expression of the MMP-9 gene in cytotrophoblast cells can be affected by matrix proteins. There was no significant difference in the expression of MMP-2 either at protein or mRNA levels among the cells cultured on the different matrix substrates. The expression of MMP-14 was regulated in a manner similar to that of MMP-2. Using ELISA, we detected higher levels of TIMP-1 in the culture medium of cells grown on VN, LN, and FN compared with that grown on Col I. But the expression of TIMP-3 mRNA was remarkably inhibited by VN, and ECM proteins had no effect on TIMP-1 and TIMP-2 mRNA expression. It was also observed that cultured cytotrophoblast cells expressed the corresponding receptors for the tested matrix proteins, such as integrins alpha(1), alpha(5), alpha(6), beta(1), and beta(4). Furthermore, the adhesiveness of cytotrophoblast cells on Col I, Col IV, FN, and LN was increased by 62%, 45%, 21%, and 22%, respectively, when compared with adhesiveness on VN. Isolated cytotrophoblast cells remained stationary when cultured on dishes coated with Col I and Col IV, but they assumed a more motile morphology and aggregated into a network when cultured on LN and VN. These data indicate that human trophoblast cells interact with their microenvironment to control their behavior and function.
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Han X, Xu P, Xu C, Zhao L, Mo Z, Liu T. Study of the effects of nanometer β-Ni(OH)2 in nickel hydroxide electrodes. Electrochim Acta 2005. [DOI: 10.1016/j.electacta.2004.11.025] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Wang SN, Xu P, Tang HZ, Meng J, Liu XL, Huang J, Chen H, Du Y, Blankespoor HD. Biodegradation and detoxification of nicotine in tobacco solid waste by a Pseudomonas sp. Biotechnol Lett 2005; 26:1493-6. [PMID: 15604785 DOI: 10.1023/b:bile.0000044450.16235.65] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A Pseudomonas sp. grew with nicotine optimally 3 g l(-1) and at 30 degrees C and pH 7. Nicotine was fully degraded within 10 h. The resting cells degraded nicotine in tobacco solid waste completely within 6 h in 0.02 m sodium phosphate buffer (pH 7) at maximally 56 mg nicotine h(-1) g dry cell(-1).
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Research Support, Non-U.S. Gov't |
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Wang C, Xu P, Ren L, Dong G, Ye L. Comparison of post-obturation pain experience following one-visit and two-visit root canal treatment on teeth with vital pulps: a randomized controlled trial. Int Endod J 2010; 43:692-7. [DOI: 10.1111/j.1365-2591.2010.01748.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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