Possible role of horizontal gene transfer in the colonization of sea ice by algae

Diatoms and other algae not only survive, but thrive in sea ice. Among sea ice diatoms, all species examined so far produce ice-binding proteins (IBPs), whereas no such proteins are found in non-ice-associated diatoms, which strongly suggests that IBPs are essential for survival in ice. The restricted occurrence also raises the question of how the IBP genes were acquired. Proteins with similar sequences and ice-binding activities are produced by ice-associated bacteria, and so it has previously been speculated that the genes were acquired by horizontal transfer (HGT) from bacteria. Here we report several new IBP sequences from three types of ice algae, which together with previously determined sequences reveal a phylogeny that is completely incongruent with algal phylogeny, and that can be most easily explained by HGT. HGT is also supported by the finding that the closest matches to the algal IBP genes are all bacterial genes and that the algal IBP genes lack introns. We also describe a highly freeze-tolerant bacterium from the bottom layer of Antarctic sea ice that produces an IBP with 47% amino acid identity to a diatom IBP from the same layer, demonstrating at least an opportunity for gene transfer. Together, these results suggest that the success of diatoms and other algae in sea ice can be at least partly attributed to their acquisition of prokaryotic IBP genes.     

Cloning and characterization of a novel human RNA binding protein gene PNO1.

Present work reported the cloning and characterization of a human novel RNA binding gene Partner of NOB1 (PNO1), with a length of 1637bp and a putative open reading frame of 759 bp, isolated from human kidney. It is composed of seven exons and is localized on chromosome 2p14. Western blot showed that the molecular weight of PNO1 is about 35kDa. RT-PCR results in 16 human tissues indicated that PNO1 is expressed mainly in liver, lung, spleen and kidney, slightly in thymus, testis, ovary, respectively, but not in heart, brain, skeletal muscle, placenta, pancreas, prostate, small intestine, colon and peripheral blood leukocytes. GFP fusion expression in mammalian cells exhibited its localization in the nucleus, especially in nucleoli. Subcellular localization of thirteen GFP fusion PNO1 deletion proteins showed that the region of 92-230 aa is solely responsible for its nucleolar retention, and KH domain alone is not sufficient for nucleolar retention. The PNO1 family shows significant conservation in both eukaryotes and prokaryotes.     

Association of the CTLA4 Gene with Graves' Disease in the Chinese Han Population

To determine whether genetic heterogeneity exists in patients with Graves'' disease (GD), the cytotoxic T-lymphocyte associated 4 (CTLA-4) gene, which is implicated a susceptibility gene for GD by considerable genetic and immunological evidence, was used for association analysis in a Chinese Han cohort recruited from various geographic regions. Our association study for the SNPs in the CTLA4 gene in 2640 GD patients and 2204 control subjects confirmed that CTLA4 is the susceptibility gene for GD in the Chinese Han population. Moreover, the logistic regression analysis in the combined Chinese Han cohort revealed that SNP rs231779 (allele frequencies p = 2.81×10⁻⁹, OR = 1.35, and genotype distributions p = 2.75×10⁻⁹, OR = 1.42) is likely the susceptibility variant for GD. Interestingly, the logistic regression analysis revealed that SNP rs35219727 may be the susceptibility variant to GD in the Shandong population; however, SNP, rs231779 in the CTLA4 gene probably independently confers GD susceptibility in the Xuzhou and southern China populations. These data suggest that the susceptibility variants of the CTLA4 gene varied between the different geographic populations with GD.     

Differential expression of 2′∶3′-cyclic nucleotide 3′-phosphodiesterase in cultured central,peripheral, and extraneural cells

The relative levels of the central nervous system myelin marker enzyme 2:3-cyclic nucleotide 3-phosphodiesterase (EC 3.1.4.37, CNPase) were determined in neuroblastoma, astrocyte, oligodendrocyte and Schwann cell cultures and in freshly isolated human lymphocytes and platelets. The highest specific activities were associated with the cells that elaborate myelin membrane in the central and peripheral nervous system, oligodendrocytes and Schwann cells, respectively. Antiserum to bovine CNPase recognized both CNP1 and CNP2 in CNS myelin and human oligodendroglioma. In addition, a 53,000 dalton protein was evident on autoradiographs of immunoblotted PNS myelin and human oligodendroglioma proteins. Cultured rat oligodendrocyte, C₆ and mouse NA neuroblastoma CNPase appear to share common determinants with the corresponding normal rat CNS enzyme.     

Superior molasses assimilation, stress tolerance, and trehalose accumulation of baker's yeast isolated from dried sweet potatoes (hoshi-imo)

Yeast strains were isolated from dried sweet potatoes (hoshi-imo), a traditional preserved food in Japan. Dough fermentation ability, freeze tolerance, and growth rates in molasses, which are important characteristics of commercial baker's yeast, were compared between these yeast strains and a commercial yeast derivative that had typical characteristics of commercial strains. Classification tests including pulse-field gel electrophoresis and fermentation/assimilation ability of sugars showed that almost the stains isolated belonged to Saccharomyces cerevisiae. One strain, ONY1, accumulated intracellular trehalose at a higher level than commercial strain T128. Correlated with intracellular trehalose contents, the fermentation ability of high-sugar dough containing ONY1 was higher. ONY1 also showed higher freeze tolerance in both low-sugar and high-sugar doughs. The growth rate of ONY1 was significantly higher under batch and fed-batch cultivation conditions using either molasses or synthetic medium than that of strain T128. These results suggest that ONY1 has potential commercial use as baker's yeast for frozen dough and high-sugar dough.     

CD137-mediated pathogenesis from chronic hepatitis to hepatocellular carcinoma in hepatitis B virus-transgenic mice

Chronic hepatitis B virus (HBV) infection is characterized by sustained liver inflammation with an influx of lymphocytes, which contributes to the development of cirrhosis and hepatocellular carcinoma. The mechanisms underlying this immune-mediated hepatic pathogenesis remain ill defined. We report in this article that repetitive infusion of anti-CD137 agonist mAb in HBV-transgenic mice closely mimics this process by sequentially inducing hepatitis, fibrosis, cirrhosis, and, ultimately, liver cancer. CD137 mAb initially triggers hepatic inflammatory infiltration due to activation of nonspecific CD8(+) T cells with memory phenotype. CD8(+) T cell-derived IFN-γ plays a central role in the progression of chronic liver diseases by actively recruiting hepatic macrophages to produce fibrosis-promoting cytokines and chemokines, including TNF-α, IL-6, and MCP-1. Importantly, the natural ligand of CD137 was upregulated significantly in circulating CD14(+) monocytes in patients with chronic hepatitis B infection and closely correlated with development of liver cirrhosis. Thus, sustained CD137 stimulation may be a contributing factor for liver immunopathology in chronic HBV infection. Our studies reveal a common molecular pathway that is used to defend against viral infection but also causes chronic hepatic diseases.     

亨利兜兰的离体快速繁殖

1植物名称 亨利兜兰（Paphiopedilum henryanum Bream）。 2材料类别 种子。 3培养条件 种子萌发和原球茎分化培养基：（1）1/2MS;（2）1/2MS＋1g·L-1活性炭;（3）1/2MS＋1g·L-1活性炭＋100mL·L-1椰子乳;