Germline Competent Pluripotent Mouse Stem Cells Generated by Plasmid Vectors

We developed nonintegrated methods to reprogram mouse embryonic fibroblast (MEF) cells into induced pluripotent stem cells (iPSCs) using pig pOct4, pSox2, and pc-Myc as well as human hKLF4, hAID, and hTDG that were carried by plasmid vectors. The 4F method employed pOct4, pSox2, pc-Myc, and hKLF4 to derive iPSC clones with naive embryonic stem cell (ESC)-like morphology. These 4F clones expressed endogenous mouse Nanog protein and could generate chimeras. In addition to the four conventional reprogramming factors used in the 4F method, hAID and hTDG were utilized in a 6F method to increase the conversion efficiency of reprogramming by approximately five-fold. One of the 6F plasmid derived iPSC (piPSC) clones was shown to be germline transmission competent.     

<Emphasis Type="Italic">Helicobacter pylori</Emphasis> outer membrane protein,HomC, shows geographic dependent polymorphism that is influenced by the Bab family

The array of outer membrane proteins (OMPs) found in Helicobacter pylori provides a crucial component for persistent colonization within the gastric niche. Not only does H. pylori harbor a wide number of OMPs, but these OMPs often vary across strains; this likely contributes to immune evasion, adaptation during long term colonization, and potentially differential disease progression. Previous work from our group described OMP differences among the Bab family (babA, babB, and babC) and Hom family (homA and homB) from 80 American H. pylori clinical isolates (AH) and 80 South Korean H. pylori clinical isolates (KH). In the current study, we expanded our investigation to include the less well characterized Hom family member, HomC.     

RORα高表达对二烯丙基二硫抑制人胃癌细胞增殖与迁移侵袭的影响

目的观察高表达RORα对二烯丙基二硫(DADS)抑制人胃癌MGC803细胞增殖、迁移与侵袭的影响。方法集落形成实验与流式细胞术检测细胞增殖与细胞周期;细胞划痕和Transwell实验分别检测细胞迁移与侵袭。RT-PCR与Western blot分别检测RORα、MMP-9和TIMP3 mRNA与蛋白表达水平。结果RT-PCR与Western blot检测显示,RORα高表达与DADS处理较对照组与空载体组RORαmRNA与蛋白表达明显上调,DADS+RORα高表达组上调更为显著(P<0.05)。与对照组和空载体组比较,RORα高表达与DADS处理组MMP-9表达下调,TIMP3表达上调,DADS+RORα高表达组改变最为显著。集落形成实验显示,RORα高表达与DADS处理组较对照组与空载体组的集落形成率明显降低。流式细胞术显示,与对照组和空载体组比较,RORα高表达与DADS处理组G2/M期细胞比率明显升高。细胞划痕和Transwell实验显示,RORα高表达与DADS处理组细胞迁移与侵袭能力明显降低。结论RORα高表达可通过上调TIMP3与下调MMP-9促进DADS阻滞MGC803细胞G2/M期和抑制增殖与迁移侵袭。     

Induction of hepatic mitochondrial glycerophosphate dehydrogenase in rats by dehydroepiandrosterone.

Feeding the thermogenic steroid, 5-androsten-3 beta-ol-17-one (dehydroepiandrosterone, DHEA) in the diet of rats induced the synthesis of liver mitochondrial sn-glycerol 3-phosphate dehydrogenase to levels three to five times that of control rats within 7 days. The previously reported enhancement of liver cytosolic malic enzyme was confirmed. The induction of both enzymes was detectable at 0.01% DHEA in the diet, reached plateau stimulation at 0.1 to 0.2%, and was completely blocked by simultaneous treatment with actinomycin D. Feeding DHEA caused smaller, but statistically significant increases of liver cytosolic lactate, sn-glycerol 3-phosphate, and isocitrate (NADP(+)-linked) dehydrogenases but not of malate or glucose 6-phosphate dehydrogenases. The capability of DHEA to enhance mitochondrial glycerophosphate dehydrogenase and malic enzyme was influenced by the thyroid status of the rats; was smallest in thyroidectomized rats and highest in rats treated with triiodothyronine. 5-Androsten-3 beta,17 beta-diol and 5-androsten-3 beta-ol-7,17-dione were as effective as DHEA in enhancing the liver mitochondrial glycerophosphate dehydrogenase and malic enzyme. Administering compounds that induce the formation of cytochrome P450 enzymes enhanced liver malic enzyme activity but not that of mitochondrial glycerophosphate dehydrogenase. Arochlor 1254 and 3-methylcholanthrene also increased the response of malic enzyme to DHEA feeding.     

Dynamics of dissolved and particulate organic carbon in a saline and semiarid stream of southeast Spain (Chicamo stream)

Annual variations in the concentration of dissolved (DOC) and particulate organic carbon (CPOC = Coarse; FPOC = Fine; UPOC = Ultrafine) were studied in a 100 m-reach of the Chicamo stream, an intermittent saline stream in southeast Spain. DOC represented the most important fraction of organic carbon flowing in the Chicamo stream (>98%), with concentrations of about 1.7 mgC l^–1 during most of the year, reaching 2.5 mgC l^–1 in summer. One high flow episode during a rain storm in winter was characterized by a considerably increased concentration of DOC (9.4 mgC l^–1). CPOC was the dominant POC fraction. Positive and significant correlations were found for DOC and discharge, which support the idea of allochthonous inputs due to floods. There was no significant correlation between POC and discharge. No significant correlations were found for DOC or POC with the physico-chemical parameters measured, while a negative significant correlation was found between DOC and temperature. The export of total organic carbon from the drainage basin of the Chicamo stream was low (6.2 × 10^–4 gC m^–2 yr^–1) and typical of streams in arid and semi-arid regions. The results of a Principal Component Analysis defined three different phases. The first consisted of short periods, during which floods provide pulses of allochthonous organic carbon and nutrients, the second a dry phase (summer), defined by biotic interactions, during which the stream could acts as a `sink' of organic matter, and the third and final phase which is characterised by hydrological stability.     

Glutathione S-transferase M1 and T1 gene polymorphism and COPD risk in smokers: an updated analysis

We evaluated the association between GSTM1 and GSTT1 gene polymorphisms and susceptibility to chronic obstructive pulmonary disease (COPD) in smokers. A meta-analysis of the published case–control studies was performed. Published literature was retrieved from PubMed, EMBASE, and China National Knowledge Infrastructure (CNKI), with last update in February, 2011. Data were extracted and a fixed- or random-effects model was used to calculate pooled odds ratios with 95% confidence intervals depending on statistical heterogeneity. Fourteen eligible studies, comprising 1,665 COPD cases and 1,614 controls, were included in the meta-analysis. The combined analyses showed that there was a significant difference in GSTM1 genotype distribution between COPD cases and controls among Caucasians, but not among Asians. The combined GSTM1/GSTT1 null genotype conferred a 1.36-fold greater risk for COPD in Asian smokers. The GSTT1 null genotype alone was not associated with enhanced risk for COPD. The GSTM1 null genotype is significantly associated with an increasing susceptibility to COPD in Caucasian smokers, but not in Asian smokers. The GSTM1/GSTT1 null genotype is a significant risk factor for developing COPD in Asian smokers. The GSTT1 null genotype, however, was not associated with COPD.     

L-serine degradation in Escherichia coli K-12: cloning and sequencing of the sdaA gene.

A new mutant of Escherichia coli K-12 unable to grow with L-serine, glycine, and L-leucine has been isolated by lambda plac Mu insertion and shown to be deficient in L-serine deaminase activity. The corresponding gene, sdaA, has been cloned from a prototrophic strain, and the clone has been characterized and sequenced. The evidence is consistent with the hypothesis that sdaA is the structural gene for L-serine deaminase. However, other possibilities are also considered. No significant homology with previously reported DNA or protein sequences was detected.     

Synthesis and characterization of a new bioactivated paramagnetic gadolinium(III) complex [Gd(DOTA-FPG)(H2O)] for tracing gene expression

A smart contrast agent for magnetic resonance imaging (MRI) can be used to exploit an enzymatic activity specific to the tissue or disease state signified by converting an MRI-inactivated agent to an activated MRI agent. In this study, a beta-galactopyranose-containing gadolinium(III) complex [Gd(DOTA-FPG)(H 2O)] was designed, synthesized, and characterized as being potentially suitable for a bioactivated MRI contrast agent. The (17)O NMR experiments were conducted to estimate the water exchange rate k e x 298 and rotational correlation time tau R 298 . The k ex 298 value of [Gd(DOTA-FPG)(H 2O)] is similar to that of [Gd(DO3A-bz-NO 2)(H 2O)]. The rotational correlation time value of [Gd(DOTA-FPG)(H 2O)] is dramatically longer than that of [Gd(DOTA)(H 2O)] (-) Relaxometric studies show that the percentage change in the T 1 value of [Gd(DOTA-FPG)(H 2O)] decreases dramatically in the presence of beta-galactosidase and human serum albumin. The T(1) change percentage of [Gd(DOTA-FPG)(H 2O)] (60%) is significantly higher than those of Egad and gadolinium(III)-1-(4-(2-(1-(4,7,10-triscarboxymethyl-(1,4,7,10-tetraazacyclododecyl)))-ethylcarbamoyloxymethyl)-2-nitrophenyl)-beta- d-glucopyronuronate. The signal intensity of the MR image for [Gd(DOTA-FPG)(H 2O)] in the presence of human serum albumin and beta-galactosidase (2670 +/- 210) is significantly higher than that of [Gd(DOTA-FPG)(H 2O)] in the sodium phosphate buffer solution (1490 +/- 160). In addition, the MR images show a higher-intensity enhancement in CT26/beta-gal tumor with beta-galactosidase gene expression but not for the CT26 tumor without beta-galactosidase gene expression. We conclude that [Gd(DOTA-FPG)(H 2O)] is a suitable candidate for a bioactivated MRI contrast agent in tracing gene expression.