Cell Surface Display of MerR on <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis> for Biosorption of Mercury

The metalloregulatory protein MerR which plays important roles in mer operon system exhibits high affinity and selectivity toward mercury (II) (Hg²⁺). In order to improve the adsorption ability of Saccharomyces cerevisiae for Hg²⁺, MerR was displayed on the surface of S. cerevisiae for the first time with an α-agglutinin-based display system in this study. The merR gene was synthesized after being optimized and added restriction endonuclease sites EcoR I and Mlu I. The display of MerR was indirectly confirmed by the enhanced adsorption ability of S. cerevisiae for Hg²⁺ and colony PCR. The hydride generation atomic absorption spectrometry was applied to measure the Hg²⁺ content in water. The engineered yeast strain not only showed higher tolerance to Hg, but also their adsorption ability was much higher than that of origin and control strains. The engineered yeast could adsorb Hg²⁺ under a wide range of pH levels, and it could also adsorb Hg²⁺ effectively with Cd²⁺ and Cu²⁺ coexistence. Furthermore, the engineered yeast strain could adsorb ultra-trace Hg²⁺ effectively. The results above showed that the surface-engineered yeast strain could adsorb Hg²⁺ under complex environmental conditions and could be used for the biosorption and bioremediation of environmental Hg contaminants.     

Discovery of novel jaspine B analogues as autophagy inducer

A series of 2-alkylaminomethyl jaspine B analogues were synthesized and evaluated for their cytotoxic effects on human lung adenocarcinoma, breast cancer, and prostate cancer cell lines and a mouse melanoma cell line. Most of the compounds exhibited moderate to good activity against the cancer cell lines. Compound 7f showed the best overall cytotoxicity on PC-3 cells (IC₅₀?=?0.85?μM). Further mechanistic studies revealed that compound 7f induced marked changes in PC-3 cell morphology, disrupted the mitochondrial membrane potential, and increased expression of the autophagy proteins beclin-1, LC3, and P62.     

Silica‐Protected Ultrathin Ni3FeN Nanocatalyst for the Efficient Hydrolytic Dehydrogenation of NH3BH3

Transition metal nitrides (TMNs) inevitably aggregate in the high‐temperature thermal ammonolysis process, resulting in blocking of the active catalytic sites and serious decreases in their corresponding catalytic performance. Therefore, how to synthesize ultrasmall TMNs with higher exposed unsaturated coordination sites is still a challenge. Herein, ultrathin Ni₃FeN (Ni₃FeN@SiO₂) with the size of ≈ 20 nm and thickness of ≈ 3.0 nm is fabricated by SiO₂ protection strategy. The obtained Ni₃FeN@SiO₂ displays outstanding performance in NH₃BH₃ hydrolytic dehydrogenation due to the high specific surface area, intrinsic metal‐vacancies, and hydrophilic SiO₂ layer.     

Aldehyde dehydrogenase 2 Glu504Lys variant predicts a worse prognosis of acute coronary syndrome patients

Aldehyde dehydrogenase 2 (ALDH2) Glu504Lys variant was an independent risk factor for acute coronary syndrome (ACS). However, there are lacking researches about the relationship between the variant and prognosis of ACS. In the prospective study, 377 ACS patients were grouped into the wild‐type (*1/*1) and the mutation (*2/*2 + *1/*2) groups according to genotype detection. Compared with the wild‐type group, incidences of major adverse cardiac events (MACE) and cardiac death were both higher in the mutation group (9.2% vs 21.0%, P = .002; 5.2% vs 12.2%, P = .026); the MACE‐free and the cardiac‐death‐free cumulative survival rates were obviously lower in the mutation group. Moreover, the mutant genotypes were associated with significantly increased risk of MACE and cardiac death (HR 2.443, 95%CI: 1.390‐4.296, P = .002; HR 2.727, 95%CI: 1.303‐5.708, P = .008). These results suggested that ALDH2 Glu504Lys variant could predict a worse prognosis of ACS patients.     

Application of multiple-quantum line narrowing with simultaneous 1H and 13C constant-time scalar-coupling evolution in PFG-HACANH and PFG-HACA(CO)NH triple-resonance experiments

Many triple-resonance experiments make use of one-bond heteronuclear scalar couplings toestablish connectivities among backbone and/or side-chain nuclei. In medium-sized(15–30 kDa) proteins, short transverse relaxation times of C single-quantum stateslimit signal-to-noise (S/N) ratios. These relaxation properties can be improved usingheteronuclear multiple-quantum coherences (HMQCs) instead of heteronuclear single-quantumcoherences (HSQCs) in the pulse sequence design. In slowly tumbling macromolecules, theseHMQCs can exhibit significantly better transverse relaxation properties than HSQCs.However, HMQC-type experiments also exhibit resonance splittings due to multiple two- andthree-bond homo- and heteronuclear scalar couplings. We describe here a family of pulsed-field gradient (PFG) HMQC-type triple-resonance experiments using simultaneous 1H and13C constant-time (CT) periods to eliminate the t1 dependence of these scalar couplingeffects. These simultaneous CT PFG-(HA)CANH and PFG-(HA)CA(CO)NH HMQC-typeexperiments exhibit sharper resonance line widths and often have better S/N ratios than thecorresponding HSQC-type experiments. Results on proteins ranging in size from 6 to 30 kDashow average methine CH HMQC:HSQC enhancement factors of 1.10 ± 0.15, withabout 40% of the cross peaks exhibiting better S/N ratios in the simultaneous CT-HMQCversions compared with the HSQC versions.     

与麦芽糖结合蛋白构象有关的单克隆抗体的制备

利用麦芽糖结合蛋白（ＭＢＰ）在大肠杆菌中的高效表达,分别采用亲和层析和变性复性,疑胶过滤的方法纯化了可溶性和包涵体部分的ＭＢＰ。将得到的这两种构象不同的ＭＢＰ分别免疫小鼠并进一步筛选和克隆,各得到５株单克隆抗体株。经制备腹水获得抗体后,地其和构象不同的麦芽糖结合蛋白的结合能力的测定,发现由包涵体部分的ＭＢＰ轩和筛选得到的单克隆抗体中有两对变性蛋白具有更高的结合能力。     

小鼠卵慢速和快速降温及玻璃化冻存的比较研究

本文用４种冷冻模式：慢速降温（ＳＬ）,超快速降温（Ｑ１）和防冻剂组成不同的玻璃化法（Ｒ－ＦＶＭ和ＭＶＭ）对昆明小鼠卵进行冷冻保存的比较研究,并用体外受精技术检测冷冻复苏卵的受精能力。ＳＬ和Ｒ－ＦＶＭ的存活率分别为５５．１±１．２和６５．９±７．９,显著高于Ｑ１（２４．２±７．３）和ＭＶＭ（４．５±２．４）其受精率分别为７２．８±１．８和７３．９±０．４显著高于Ｑ１（５８．６±１１．２）和ＭＶＭ（４１．５±８．５）,而与对照组（７７．５±３．９）相似。结果表明：１）慢速降温程序（ＳＬ）和同时含有渗透性和非渗透性防冻剂的玻璃化法（Ｆ—ＲＶＭ）较适宜昆明小鼠卵的冻存;２）同时考虑冻存过程中的冰晶损伤和渗透压损伤是获得较好冻存结果的关键。     

广义Lyapunov函数与微分系统关于两种量度的相对稳定(Ⅱ)

利用广义Lyapunov函数来研究微分系统关于两种量度的相对稳定性,讨论它们之间的关系。得出微分系统关于两种量度的相对稳定性等价于广义Lyapunov函数具有某种相应的性质。     

Sequence analysis and characterization of a 40-kilodalton Borrelia hermsii glycerophosphodiester phosphodiesterase homolog.

We report the purification, molecular cloning, and characterization of a 40-kDa glycerophosphodiester phosphodiesterase homolog from Borrelia hermsii. The 40-kDa protein was solubilized from whole organisms with 0.1% Triton X-100, phase partitioned into the Triton X-114 detergent phase, and purified by fast-performance liquid chromatography (FPLC). The gene encoding the 40-kDa protein was cloned from a B. hermsii chromosomal DNA lambda EXlox expression library and identified by using affinity antibodies generated against the purified native protein. The deduced amino acid sequence included a 20-amino-acid signal peptide encoding a putative leader peptidase II cleavage site, indicating that the 40-kDa protein was a lipoprotein. Based on significant homology (31 to 52% identity) of the 40-kDa protein to glycerophosphodiester phosphodiesterases of Escherichia coli (GlpQ), Bacillus subtilis (GlpQ), and Haemophilus influenzae (Hpd; protein D), we have designated this B. hermsii 40-kDa lipoprotein a glycerophosphodiester phosphodiesterase (Gpd) homolog, the first B. hermsii lipoprotein to have a putative functional assignment. A nonlipidated form of the Gpd homolog was overproduced as a fusion protein in E. coli BL21(DE3)(pLysE) and was used to immunize rabbits to generate specific antiserum. Immunoblot analysis with anti-Gpd serum recognized recombinant H. influenzae protein D, and conversely, antiserum to H. influenzae protein D recognized recombinant B. hermsii Gpd (rGpd), indicating antigenic conservation between these proteins. Antiserum to rGpd also identified native Gpd as a constituent of purified outer membrane vesicles prepared from B. hermsii. Screening of other pathogenic spirochetes with anti-rGpd serum revealed the presence of antigenically related proteins in Borrelia burgdorferi, Treponema pallidum, and Leptospira kirschneri. Further sequence analysis both upstream and downstream of the Gpd homolog showed additional homologs of glycerol metabolism, including a glycerol-3-phosphate transporter (GlpT), a glycerol-3-phosphate dehydrogenase (GlpD), and a thioredoxin reductase (TrxB).     

前乐平统海洋动物灾变事件

作为古生代最后阶段的乐平统可划分为２个阶和４个亚阶,暂以逼近自然界线的Ｃｌａｒｋｉｎａ ｐｏｓｔｂｉｔｔｅｒｉ带之底为下界;在二叠纪形成了栖霞期之前和吴家坪期之前两个超序界面,乐平世海侵居于二叠一三叠纪超序的低水位体系,乐平世末的海泛淹没了古特提斯区的残留陆棚;二叠纪末的生物大绝灭形成规模和性质不同的两幕;茅口期末全球性海退使栖居地丧失而导致地方性类群和远洋浮游生物灭亡的前乐平统海泮动物灾变事件,