藏鸡微卫星文库的构建与微卫星标记筛选

通过磁珠富集法构建了藏鸡基因组微卫星富集文库,分离微卫星序列并对其进行分析.将藏鸡基因组DNA经Sau3AI酶切后纯化回收,连接特定接头.用生物素标记的(CA)12探针与藏鸡基因组酶切回收片段杂交,捕获200～900 bp片段,随后将获得的片段连接到pMD 18-T载体上,转化至JM109中,成功构建藏鸡微卫星富集文库.从1200个转化子中获得了353个阳性克隆,随机挑选53个测序,根据测序结果成功设计了18对藏鸡微卫星引物,最终筛选出6个具有多态性的微卫星标记,其PIC值均大于0.5,同时可以用于研究藏鸡遗传多样性.实验结果表明磁珠富集法能够有效提高分离微卫星标记的效率.     

Purification of aquarium water by PVA gel-immobilized photosynthetic bacteria during goldfish rearing

This study was conducted to evaluate the ability of a PVA-gel beads filtration (PVA) system using photosynthetic bacteria to purify water. To accomplish this, duplicate long-term goldfish rearing experiments were conducted using four different types of aquarium systems (COF, PSB, EMC, and PVA). The results revealed that the concentrations of NH₄ ⁺-N on the day of a goldfish’s death were significantly higher than the concentrations on other days for all the aquarium systems. In addition, the mean concentration of NH₄ ⁺-N during goldfish rearing occurred in the following order: COF system > EMC system > PSB system > PVA system. Furthermore, the mean values of all other ion concentrations (NO₃ ⁻-N, NO₂ ⁻-N, and PO₄ ²⁻-P) were found to be lowest in the PVA system. As a result, there was more prominent decomposition of organic matter in the aquarium tank containing the PVA system, as well as less turbid aquarium water and more active goldfish. Additionally, the PVA-gel beads resulted in almost complete denitrification, even after six-months of goldfish rearing. To our knowledge, this is the first study to report that PVA gel-immobilized photosynthetic bacteria have the ability to purify water. Overall, the results of this study indicate that this immobilized photosynthetic bacteria system has the potential for use as a component in circulating filtration systems.     

NGFI-B targets mitochondria and induces cardiomyocyte apoptosis in restraint-stressed rats by mediating energy metabolism disorder

NGFI-B/Nur77/TR3, originally identified as an immediate-early gene rapidly induced by serum and growth factors, is a member of the steroid hormone nuclear receptor superfamily with no identified endogenous ligand. NGFI-B induces apoptosis in a number of cell lineages exposed to proapoptotic stimuli by directly targeting the mitochondria, inducing cytochrome c release. The present study was designed to determine the role of NGFI-B in cardiomyocytes of restraint-stressed rats. The NGFI-B content was increased in mitochondria and reduced in plasma as apoptosis increased. Analysis showed that NGFI-B induces cardiomyocyte apoptosis in restraint-stressed rats by mediating mitochondrial energy metabolism disorder. Several novel mitochondrial proteins, which correlate with NGFI-B, were reported in cardiomyocyte apoptosis of restraint-stressed rats. Five proteins associated with NGFI-B participate directly in mitochondrial energy metabolism. Studies of mitochondrial respiratory efficiency and ATP synthase activity strongly support the findings. These results provide significant information for comprehensively understanding the cellular mechanism of cardiovascular diseases.     

Aligning the proteome and genome of the silkworm, Bombyx mori

A technology of mass spectrometry (MS) was used in this study for the large-scale proteomic identification and verification of protein-encoding genes present in the silkworm (Bombyx mori) genome. Peptide sequences identified by MS were compared with those from an open reading frame (ORF) library of the B. mori genome and a cDNA library, to validate the coding attributes of ORFs. Two databases were created. The first was based on a 9× draft sequence of the silkworm genome and contained 14,632 putative proteins. The second was based on a B. mori pupal cDNA library containing 3,187 putative proteins of at least 30 amino acid residues in length. A total of 81,000 peptide sequences with a threshold score of 60% were generated by the MS/MS analysis, and 55,400 of these were chosen for a sequence alignment. By searching these two databases, 6,649 and 250 proteins were matched, which accounted for approximately 45.4% and 7.8% of the peptide sequences and putative proteins, respectively. Further analyses carried out by several bioinformatic tools suggested that the matches included proteins with predicted transmembrane domains (1,393) and preproteins with a signal peptide (976). These results provide a fundamental understanding of the expression and function of silkworm proteins.     

Seasonal variation of mixing depth and its influence on phytoplankton dynamics in the Zeya reservoir, China

In reservoirs or lakes, mixing depth affects growth and loss rates of phytoplankton populations. Based on 1-year data from the Zeya reservoir, China, we scaled the mixing depth throughout a whole year by utilizing cluster analysis, and then investigated its influence on phytoplankton dynamics and other physical and chemical parameters. Over the whole year, all physical and chemical parameters except TN and temperature had significant correlations with mixing depth, indicating that mixing depth is one of the important driving factors influencing water environment. According to mixing depth, a year can be divided into three different periods, including the thermally stratified period, isothermally mixed period, and transition period between them. When considering the former two different periods separately, mixing depth had no correlation with the phytoplankton biovolume. However, over the whole year a significant correlation was observed, which indicated that the influence of mixing depth on phytoplankton growth in the Zeya reservoir still followed Diehl’s theory. Furthermore, according to the steady-state assumption, a unimodal curve (mixing depth—phytoplankton biovolume) with a significant peak appearing at a mixing depth of 2 m was observed, closely agreeing with Diehl’ prediction.     

Function of SIRT1 in physiology

Sirtuins were originally defined as a family of oxidized nicotinamide adenine nucleotide (NAD⁺)-dependent enzymes that deacetylate lysine residues on various proteins. The sirtuins are remarkably conserved throughout evolution from archae to eukaryotes. They were named after their homology to the Saccharomyces cerevisiae gene silent information regulator 2 (Sir2). The mammalian sirtuins, SIRT1-7, are implicated in a variety of cellular functions ranging from gene silencing, control of the cell cycle and apoptosis, and energy homeostasis. As SIRT1 is a nuclear protein and is the mammalian homolog most highly related to Sir2, it has been the focus of a large number of recent studies. Here we review some of the current data related to SIRT1 and discuss its mode of action and biological role in cellular and organismal models. Published in Russian in Biokhimiya, 2009, Vol. 74, No. 7, pp. 869–876.     

Fusion protein of Δ27LFn and EFn has the potential as a novel anthrax toxin inhibitor

PA-binding domain of LF (LFn) or PA-binding domain of EF (EFn) is the anthrax protective antigen (PA) binding domain of anthrax lethal factor (LF) or edema factor (EF). Here we show the development of a novel anthrax toxin inhibitor, fusion protein of N-terminal 27 amino acids deletion of LFn (Δ27LFn) and EFn. In a cell model of intoxication, fusion protein of Δ27LFn and EFn (Δ27LFn-EFn) was a 62-fold more potent toxin inhibitor than LFn or EFn, and this increased activity corresponded to a 39-fold higher PA-binding affinity by Biacore analysis. More importantly, Δ27LFn-EFn could protect the highly susceptible Fischer 344 rats from anthrax lethal toxin challenge. This work suggested that Δ27LFn-EFn has the potential as a candidate therapeutic agent against anthrax.

Structured summary

MINT-7014735, MINT-7014747, MINT-7014761: PA63 (uniprotkb:P13423) and LF (uniprotkb:P15917) bind (MI:0407) by surface plasmon resonance (MI:0107)