Hydrogen sulfide regulates abiotic stress tolerance and biotic stress resistance in Arabidopsis

Hydrogen sulfide (H2S) is an important gaseous molecule in various plant developmental processes and plant stress responses. In this study, the transgenic Arabidopsis thaliana plants with modulated exp...     

Relationship of the lung microbiome with PD-L1 expression and immunotherapy response in lung cancer

IL-35 subunit EBI3 is up-regulated in pulmonary fibrosis tissues. In this study, we investigated the pathological role of EBI3 in pulmonary fibrosis and dissected the underlying molecular mechanism. Bleomycin-induced pulmonary fibrosis mouse model was established, and samples were performed gene expression analyses through RNAseq, qRT-PCR and Western blot. Wild type and EBI3 knockout mice were exposed to bleomycin to investigate the pathological role of IL-35, via lung function and gene expression analyses. Primary lung epithelial cells were used to dissect the regulatory mechanism of EBI3 on STAT1/STAT4 and STAT3. IL-35 was elevated in both human and mouse with pulmonary fibrosis. EBI3 knockdown aggravated the symptoms of pulmonary fibrosis in mice. EBI3 deficiency enhanced the expressions of fibrotic and extracellular matrix-associated genes. Mechanistically, IL-35 activated STAT1 and STAT4, which in turn suppressed DNA enrichment of STAT3 and inhibited the fibrosis process. IL-35 might be one of the potential therapeutic targets for bleomycin-induced pulmonary fibrosis.     

Analysis of pSC138, the multidrug resistance plasmid of Salmonella enterica serotype Choleraesuis SC-B67

Salmonella enterica serotype Choleraesuis (S. Choleraesuis) usually causes systemic infections in man and needs antimicrobial treatment. Multidrug resistance (MDR) in S. Choleraesuis is thus a great concern in the treatment of systemic non-typhoid salmonellosis. A large plasmid, pSC138, was identified in 2002 from a S. Choleraesuis strain SC-B67 that was resistant to all antimicrobial agents commonly used to treat salmonellosis, including ciprofloxacin and ceftriaxone. Complete DNA sequence of the plasmid had been determined previously (Chiu et al., 2005). In the present study, the sequence of pSC138 was reannotated in detail and compared with several newly sequenced plasmids. Some transposable elements and drug resistance genes were further delineated. Plasmid pSC138 was 138,742 bp in length and consisted of 177 open reading frames (ORFs). While 134 of the ORFs displayed significant identity levels to other plasmid and prokaryotic sequences, the remaining 43 ORFs have not been previously reported. Mobile elements, including two integrons, seven insertion sequences and eight transposons, and a truncated prophage together encompass at least 66,781 bp (48.1%) of the plasmid genome. The sequence of pSC138 consists of three major regions: a large composite transposable region Tn6088 with a Tn21-like backbone inserted by a variety of integrons or transposable elements; a transfer/maintenance region that contains a conserved ISEcp1-mediated transposon-like element Tn6092, carrying an AmpC gene, bla(CMY-2), that confers the ceftriaxone resistance; and a Rep_3 type of replication region. Another seven bacteremic strains of S. Choleraesuis that expressed the same MDR phenotype were identified during 2003-2008. The same Rep_3 type replicase and the bla(CMY-2)-containing, ISEcp1-mediated transposon-like element were found in the MDR isolates, suggesting a successful preservation and dissemination of the MDR plasmid. Comparison of pSC138 with other recently published plasmids revealed a high identity level between partial sequences of pSC138 and plasmids of the same or different incompatibility groups. The large MDR region found in pSC138 may provide a niche for the future evolution of the plasmid by acquisition of relevant resistance genes through the panoply of mobile elements and illegitimate recombination events.     

Remodeling of nuclear architecture during the cell cycle in Drosophila embryos

Little is known about what determines the nuclear matrix or how its reorganization is regulated during mitosis. In this study we report on a monoclonal antibody, mAb2A, which identifies a novel nuclear structure in Drosophila embryos which forms a diffuse meshwork at interphase but which undergoes a striking reorganization into a spindle-like structure during pro- and metaphase. Double labelings with α-tubulin and mAb2A antibodies demonstrate that the microtubules of the mitotic apparatus co-localize with this mAb2A labeled structure during metaphase, suggesting it may serve a role in microtubule spindle assembly and/or function during nuclear division. That the mAb2A-labeled nuclear structure is essential for cell division and/or maintenance of nuclear integrity was directly demonstrated by microinjection of mAb2A into early syncytial embryos which resulted in a disintegration of nuclear morphology and perturbation of mitosis. © 1996 Wiley-Liss, Inc.     

A novel carbonyl reductase from Pichia stipitis for the production of ethyl (S)-4-chloro-3-hydroxybutanoate

An NADPH-dependent carbonyl reductase (PsCR) gene from Pichia stipitis was cloned. It contains an open reading frame of 849 bp encoding 283 amino acids whose sequence had less than 60% identity to known reductases that produce ethyl (S)-4-chloro-3-hydroxybutanoates (S-CHBE). When expressed in Escherichia coli, the recombinant PsCR exhibited an activity of 27 U/mg using ethyl 4-chloro-3-oxobutanoate (COBE) as a substrate. Reduction of COBE to (S)-CHBE by transformants in an aqueous mono-phase system for 18 h, gave a molar yield of 94% and an optical purity of the (S)-isomer of more than 99% enantiomeric excess.     

黄孢原毛平革菌抗营养阻遏产漆酶诱变育种及其产酶特性

【目的】筛选能抗营养阻遏产漆酶的黄孢原毛平革菌,论证其产漆酶的确定性及抗营养阻遏产木质素酶的可行性,为白腐菌产酶代谢调控、木质素降解机理的研究奠定基础。【方法】利用重复紫外诱变法,以愈创木酚富氮鉴别培养基筛选目标菌株;比较不同营养条件下菌体生长与产酶动力学差异研究产酶营养调控机理;通过热处理、排除锰离子和加入过氧化氢酶等不同措施论证黄孢原平毛平革菌能否产生漆酶。【结果】3种不同方法均证实选育到的pcR5305和pcR5324菌株在限氮与富氮条件下均能产生漆酶,pcR5305和pcR5324在限氮条件下产漆酶分别达到203.5、187.6 U/L;在富氮条件下为220.6、183.9 U/L,而原菌株pc530在两种条件下都基本不产生漆酶。二菌株产漆酶调控方式不同,pcR5305漆酶产生与菌体生长同步,而pcR5324漆酶产生却受营养氮阻遏。二菌株同时具有抗营养阻遏高产木质素过氧化物酶(LiP)和锰过氧化物酶(MnP)(分别为LiP 1343.2、MnP 252.2 U/L;LiP 1169.5、MnP 172.4 U/L)的能力。【结论】筛选到的黄孢原毛平革菌变异菌株能产漆酶,同时表现了抗营养阻遏产漆酶、木质素过氧化物酶和锰过氧化物酶的能力,具有重要的生产应用与理论研究价值,为白腐菌产酶代谢调控机理研究提供了原始菌株并奠定了良好的基础。     

慢性缺氧对大鼠左右心室功能、心肌肌原纤维Ca~（2＋），Mg~（2＋）－ATP

模拟５０００ｍ中度缺氧时,大鼠右室功能显著加强,而左室功能加强不显著;左右心室肌原纤维Ｃａ２＋,Ｍｇ２＋－ＡＴＰ酶活性下降,肌球蛋白同功酶Ｖ２和Ｖ３百分含量增加,Ｖ１百分含量减少。８０００ｍ重度缺氧时,右室功能减弱,但无统计学意义,左室功能减弱有显著性;ＡＴＰ酶活性和同功酶的变化超过５０００ｍ组。此外,右室ＡＴＰ酶活性与ＰＡＰ呈反比且有显著性,左室ＡＴＰ酶活性与ＣＡＳＰ虽也呈反比但无显著性;右室同功酶Ｖ３百分含量与ＰＡＰ呈正比,左室同功酶Ｖ３百分含量与ＣＡＳＰ不呈比例。上述结果表明,因短期突发严重缺氧引起的心肌供氧不足对左心室心肌的直接损伤作用大于右心室心肌。