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排序方式: 共有268条查询结果,搜索用时 46 毫秒
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Jeffrey T. Lell Michael D. Brown Theodore G. Schurr R. I. Sukernik Yelena B. Starikovskaya Antonio Torroni Lorna G. Moore Gary M. Troup D. C. Wallace 《Human genetics》1997,100(5-6):536-543
We have initiated a study of ancient male migrations from Siberia to the Americas using Y chromosome polymorphisms. The first
polymorphism examined, a C→T transition at nucleotide position 181 of the DYS199 locus, was previously reported only in Native
American populations. To investigate the origin of this DYS199 polymorphism, we screened Y chromosomes from a number of Siberian,
Asian, and Native American populations for this and other markers. This survey detected the T allele in all five Native American
populations studied at an average frequency of 61%, and in two of nine native Siberian populations, the Siberian Eskimo (21%)
and the Chukchi (17%). This finding suggested that the DYS199 T allele may have originated in Beringia and was then spread
throughout the New World by the founding populations of the major subgroups of modern Native Americans. We further characterized
Native American Y chromosome variation by analyzing two additional Y chromosome polymorphisms, the DYS287 Y Alu polymorphic (YAP) element insertion and a YAP-associated A→G transition at DYS271, both commonly found in Africans. We found
neither African allele associated with the DYS199 T allele in any of the Native American or native Siberian populations. However,
we did find DYS287 YAP+ individuals who harbored the DYS199 C allele in one Native American population, the Mixe, and in one
Asian group, the Tibetans. A correlation of these Y chromosome alleles in Native Americans with those of the DYS1 locus, as
detected by the p49a/p49f (p49a,f) probes on TaqI-digested genomic DNA, revealed a complete association of DYS1 alleles (p49a,f haplotypes) 13, 18, 66, 67 and 69 with the
DYS199 T allele, while DYS1 alleles 8 and 63 were associated with both the DYS199 C and T allele.
Received: 18 November 1996 / Accepted: 19 May 1997 相似文献
54.
Yelena Sterlin Oded Pri‐Tal Gil Zimran Sang‐Youl Park Julius Ben‐Ari Jiorgos Kourelis Inge Verstraeten Maayan Gal Sean R. Cutler Assaf Mosquna 《The Plant journal : for cell and molecular biology》2019,98(5):928-941
Abscisic acid (ABA) receptors belong to the START domain superfamily, which encompasses ligand‐binding proteins present in all kingdoms of life. START domain proteins contain a central binding pocket that, depending on the protein, can couple ligand binding to catalytic, transport or signaling functions. In Arabidopsis, the best characterized START domain proteins are the 14 PYR/PYL/RCAR ABA receptors, while the other members of the superfamily do not have assigned ligands. To address this, we used affinity purification of biotinylated proteins expressed transiently in Nicotiana benthamiana coupled to untargeted LC‐MS to identify candidate binding ligands. We optimized this method using ABA–PYL interactions and show that ABA co‐purifies with wild‐type PYL5 but not a binding site mutant. The Kd of PYL5 for ABA is 1.1 μm , which suggests that the method has sufficient sensitivity for many ligand–protein interactions. Using this method, we surveyed a set of 37 START domain‐related proteins, which resulted in the identification of ligands that co‐purified with MLBP1 (At4G01883) or MLP165 (At1G35260). Metabolite identification and the use of authentic standards revealed that MLBP1 binds to monolinolenin, which we confirmed using recombinant MLBP1. Monolinolenin also co‐purified with MLBP1 purified from transgenic Arabidopsis, demonstrating that the interaction occurs in a native context. Thus, deployment of this relatively simple method allowed us to define a protein–metabolite interaction and better understand protein–ligand interactions in plants. 相似文献
55.
A comparison of three techniques for quantitative analysis of galactosylation present on immunoglobulins is described. ESIMS, MALDI-TOF MS, and anion-exchange chromatography with fluorescence detection were evaluated in terms of repeatability, limit of quantitation, selectivity, and linearity. A recombinant monoclonal IgG was enzymatically modified in vitro to produce essentially completely galactosylated and degalactosylated forms of the immunoglobulin. Samples of known galactosylation levels were prepared by mixing the modified forms with the native form of the immunoglobulin. Good repeatability and linearity were demonstrated for all three assays (RSDs<1.0%, correlation coefficients>0.99). Differences in selectivity, sensitivity, and other performance aspects of the three techniques are also discussed in this paper. 相似文献
56.
Delta-9-tetrahydrocannabinol protects cardiac cells from hypoxia via CB2 receptor activation and nitric oxide production 总被引:2,自引:0,他引:2
Shmist YA Goncharov I Eichler M Shneyvays V Isaac A Vogel Z Shainberg A 《Molecular and cellular biochemistry》2006,283(1-2):75-83
Delta-9-tetrahydrocannabinol (THC), the major active component of marijuana, has a beneficial effect on the cardiovascular
system during stress conditions, but the defence mechanism is still unclear. The present study was designed to investigate
the central (CB1) and the peripheral (CB2) cannabinoid receptor expression in neonatal cardiomyoctes and possible function
in the cardioprotection of THC from hypoxia. Pre-treatment of cardiomyocytes that were grown in vitro with 0.1 – 10 μM THC for 24 h prevented hypoxia-induced lactate dehydrogenase (LDH) leakage and preserved the morphological
distribution of α-sarcomeric actin. The antagonist for the CB2 (10 μM), but not CB1 receptor antagonist (10 μM) abolished
the protective effect of THC. In agreement with these results using RT-PCR, it was shown that neonatal cardiac cells express
CB2, but not CB1 receptors. Involvement of NO in the signal transduction pathway activated by THC through CB2 was examined.
It was found that THC induces nitric oxide (NO) production by induction of NO synthase (iNOS) via CB2 receptors. L-NAME (NOS
inhibitor, 100 μM) prevented the cardioprotection provided by THC. Taken together, our findings suggest that THC protects
cardiac cells against hypoxia via CB2 receptor activation by induction of NO production. An NO mechanism occurs also in the
classical pre-conditioning process; therefore, THC probably pre-trains the cardiomyocytes to hypoxic conditions. 相似文献
57.
Hashmi S Zhang J Oksov Y Ji Q Lustigman S 《The Journal of biological chemistry》2006,281(38):28415-28429
In the present study, we characterized a sterile cpi-2a(ok1256) deletion mutant in Caenorhabditis elegans and showed that CPI-2a has an essential regulatory role during oogenesis and fertilization. We have also shown that the CPI2a inhibitor and both Ce-CPL-1 and Ce-CPZ-1 enzymes are present in the myoepithelial sheath surrounding germ cells, oocytes, and embryos as well as in the yolk granules within normal oocytes. Staining of mutant worms with anti-yolk protein antibodies has indicted that the proteins are not present in the mature oocytes. Moreover, green fluorescent protein expression was absence or reduced in cpi-2a/yp170:gfp mutant oocytes, although it was expressed in one of the successfully developed embryos. Based on these results, we hypothesize that the sterility in cpi-2a(ok1256) mutant worms is potentially caused by two possible mechanisms: 1) defects in the uptake and/or processing of yolk proteins by the growing oocytes and 2) indirect induction of defects in cell-cell signaling that is critical for promoting germ line development, oocyte maturation, ovulation, and fertilization. A defect in any of these processes would have detrimental effects on the development of normal embryos and consequently normal production of progenies as we observed in cpi-2a mutant worms. This is the first study that demonstrates the expression of cysteine proteases and their endogenous inhibitor in the gonadal sheath cells surrounding germ cells and oocytes, which indirectly have established their potential involvement in proteolytic processing of molecules within the gonadal sheath cells, such as components of the extracellular matrix or the cytoskeletal proteins, which are essential for proper cell-cell signaling activities of the gonadal sheath cells during normal maturation and ovulation processes. 相似文献
58.
59.
Lance B. Price Cindy M. Liu Johan H. Melendez Yelena M. Frankel David Engelthaler Maliha Aziz Jolene Bowers Rogan Rattray Jacques Ravel Chris Kingsley Paul S. Keim Gerald S. Lazarus Jonathan M. Zenilman 《PloS one》2009,4(7)
Background
Bacterial colonization is hypothesized to play a pathogenic role in the non-healing state of chronic wounds. We characterized wound bacteria from a cohort of chronic wound patients using a 16S rRNA gene-based pyrosequencing approach and assessed the impact of diabetes and antibiotics on chronic wound microbiota.Methodology/Principal Findings
We prospectively enrolled 24 patients at a referral wound center in Baltimore, MD; sampled patients'' wounds by curette; cultured samples under aerobic and anaerobic conditions; and pyrosequenced the 16S rRNA V3 hypervariable region. The 16S rRNA gene-based analyses revealed an average of 10 different bacterial families in wounds—approximately 4 times more than estimated by culture-based analyses. Fastidious anaerobic bacteria belonging to the Clostridiales family XI were among the most prevalent bacteria identified exclusively by 16S rRNA gene-based analyses. Community-scale analyses showed that wound microbiota from antibiotic treated patients were significantly different from untreated patients (p = 0.007) and were characterized by increased Pseudomonadaceae abundance. These analyses also revealed that antibiotic use was associated with decreased Streptococcaceae among diabetics and that Streptococcaceae was more abundant among diabetics as compared to non-diabetics.Conclusions/Significance
The 16S rRNA gene-based analyses revealed complex bacterial communities including anaerobic bacteria that may play causative roles in the non-healing state of some chronic wounds. Our data suggest that antimicrobial therapy alters community structure—reducing some bacteria while selecting for others. 相似文献60.
The DEL assay in yeast detects DNA deletions that are inducible by many carcinogens. Here we use the colorimetric agent MTS to adapt the yeast DEL assay for microwell plate measurement of ionizing radiation-induced cell killing and DNA deletions. Using the microwell-based DEL assay, cell killing and genotoxic DNA deletions both increased with radiation dose between 0 and 2000 Gy. We used the microwell-based DEL assay to assess the effectiveness of varying concentrations of five different radioprotectors, N-acetyl-l-cysteine, l-ascorbic acid, DMSO, Tempol and Amifostine, and one radiosensitizer, 5-bromo-2-deoxyuridine. The microwell format of the DEL assay was able to successfully detect protection against and sensitization to both radiation-induced cytotoxicity and genotoxicity. Such radioprotection and sensitization detected by the microwell-based DEL assay was validated and compared with similar measurements made using the traditional agar-based assay format. The yeast DEL assay in microwell format is an effective tool for rapidly detecting chemical protectors and sensitizers to ionizing radiation and is automatable for chemical high-throughput screening purposes. 相似文献