气肿疽梭菌C54-1株的制备与检定

为研究气肿疽梭菌C54-1株(CVCC60001)的菌种特性,制备了1批气肿疽梭菌C54-1株,并对菌种的形态及生化特性、培养特性、血清学特性、真空度、纯粹、剩余水分、毒力及免疫原性、16S rDNA等进行检定,以及对于该菌的适宜培养基促生长能力等方面进行了比较。实验结果表明,该冻干菌种的形态及生化特性、培养特性、血清学特性、真空度、纯粹、剩余水分、毒力及免疫原性均符合《中华人民共和国兽用生物制品规程》二〇〇〇版质量标准的规定。16S rDNA鉴定为气肿疽梭菌,相似度为99.93%。在免疫原性检定中,使用致死剂量攻毒时,免疫组能够4/4被保护,证明该菌明矾苗免疫效果良好。使用商品化梭菌培养基对于该菌培养进行了比对,证实商品化培养基替代厌气肉肝汤的可能性。本研究为气肿疽梭菌的制备和检定提供参考依据,并使用不同培养基进行比对研究,为该菌的稳定培养和疫苗工艺改进提供了研究基础。

HIV-1 Transmission among Injecting Drug Users is Principally Derived from Local Circulating Strains in Guangxi, China

Objective The mode of human immunodeficiency virus(HIV) transmission via injection drug use(IDU)still exists, and the recent shift in IDU-related transmission of HIV infection is largely unknown. The purpose of this study was to analyze the spatiotemporal sources and dynamics of HIV-1 transmission through IDU in Guangxi.Methods We performed a molecular epidemiological investigation of infections across Guangxi from2009 to 2019. Phylogenetic and Bayesian time-geographic analyses of HIV-1 sequences were performed to confirm the characteristics of transmission between IDUs in combination with epidemiological data.Results Among the 535 subjects, CRF08_BC(57.4%), CRF01_AE(28.4%), and CRF07_BC(10.7%) were the top 3 HIV strains;72.6% of infections were linked to other provinces in the transmission network;93.6% of sequence-transmitted strains were locally endemic, with the rest coming from other provinces,predominantly Guangdong and Yunnan;92.1% of the HIV transmission among people who inject drugs tended to be transmitted between HIV-positive IDUs.Conclusion HIV recombinants were high diversity, and circulating local strains were the transmission sources among IDUs in Guangxi. However, there were still cases of IDUs linked to other provinces.Coverage of traditional prevention strategies should be expanded, and inter-provincial collaboration between Guangxi, Yunnan, and Guangdong provinces should be strengthened.

HSV-1突变株M6感染人支气管上皮细胞后对巨噬细胞介导的免疫反应的影响

目的探究1型单纯疱疹病毒(herpes simplex virus type 1,HSV-1)突变株M6感染人支气管上皮细胞(16HBE细胞)后对巨噬细胞介导的免疫反应的影响。方法用HSV-1感染16HBE细胞分析培养液中细胞因子的变化;将巨噬细胞与被HSV-1毒株感染的16HBE细胞的上清液共培养并通过尾静脉回输至小鼠体内,分别在第1、3、7、28、56、90天对小鼠淋巴结细胞因子表达水平、脾脏T细胞比例变化、小鼠中和抗体表达水平以及特异性T细胞反应进行检测。结果16HBE细胞被HSV-1突变株感染后,上清液中募集和激活巨噬细胞相关的细胞因子均较高水平表达但略低于野毒株组;尾静脉回输实验后,突变株组小鼠淋巴结炎症因子、趋化因子和T细胞的比例随时间发生了不同的变化,并引起了弱于野毒株组的体液免疫和强于野毒株组的特异性T细胞免疫反应,且仅极少数与野毒株组具有显著性差异(P<0.05)。结论16HBE细胞被HSV-1突变株M6感染后能够释放募集和激活巨噬细胞的细胞因子,使巨噬细胞携带HSV-1突变株的特异性活化信息,激活了宿主的免疫系统,诱导了宿主的体液免疫和细胞免疫。

轧制应变速率对Mg-1%Al合金组织、阻尼和力学性能的影响

在不同应变速率下轧制Mg-1%Al合金板材,研究了轧制应变速率对Mg-1%Al合金显微组织、力学性能和阻尼性能的影响。随着轧制应变速率增加,Mg-1%Al合金的平均晶粒尺寸和再结晶体积分数增加;抗拉强度、屈服强度和织构强度减小;延伸率先升高后降低,在应变速率20 s^(-1)时达到最高,为25.33%。随着应变速率增加,室温阻尼性能增加,应变速率30 s^(-1)下应变振幅0.1%时阻尼值为0.061,是应变速率15 s^(-1)时的1.5倍。应变速率一定时,阻尼性能随着频率增加而降低。

猴痘病毒B.1谱系遗传分支、毒力基因及蛋白功能

2022年以来,猴痘疫情在全球暴发和流行。相较以往的猴痘病毒,2022年流行的猴痘毒株传播能力和宿主适应性等明显增强,猴痘B.1谱系毒株已成为全球猴痘疫情流行的主要毒株。为此,本文对猴痘病毒B.1谱系遗传分支、毒力基因及蛋白功能进行综述,并就部分基因产物的蛋白功能进行了注释,以期为猴痘疫情的科学防控提供参考。

对金龟子幼虫有杀虫活性的苏云金杆菌HBF-1菌株发酵培养基优选

通过正交试验优选出对金龟子幼虫有杀虫活性的苏云金杆菌HBF 1菌株的发酵培养基组合为:氮源B4 4%,淀粉1 2%,酵母粉0.5%,KH2PO40.04%,MgSO40.05%。用此配方进行摇瓶发酵,发酵液的平均菌数可达到44亿/mL,晶体产生量为2 1130mg/mL,发酵液稀释50倍对铜绿丽金龟幼虫进行生测,14d平均死亡率达到78 3%。

苏云金芽孢杆菌HBF-1芽孢对棉铃虫幼虫生长发育及酶活的影响

苏云金芽孢杆菌HBF-1菌株的芽孢对初孵棉铃虫幼虫无明显杀伤作用,但可以直接影响其正常的生长发育,使幼虫前期体重增加;而后期发育迟缓,历期延长,成虫产卵量明显减少。通过光学显微镜观察发现,用含有HBF-1芽孢的饲料饲喂棉铃虫幼虫,幼虫中肠肠壁细胞遭到破坏;随着虫龄的增大,微绒毛逐渐脱落,有的部位细胞壁破裂。酶活的测定结果表明:初孵棉铃虫幼虫取食含有HBF-1芽孢(100μg/g)的饲料后,幼虫体内的乙酰胆碱酯酶、羧酸酯酶和谷胱甘肽-S-转移酶的活性发生了变化。

苏云金杆菌HBF-1菌株的活芽孢对HD-1菌株增效作用的特异性

通过HBF-1菌株培养物各组分与HD-1菌株混合对棉铃虫的LC50测定结果表明,HBF-1孢晶混合物对HD-1的纯晶体和孢晶混合物分别增效170.0%、80.0%,HBF-1活芽孢对HD-1的纯晶体和孢晶混合物分别增效240.0%、160.0%,HBF-1纯晶体和死芽孢均无增效作用。在一定范围内,随着HBF-1菌株活芽孢浓度的增高,其增效作用逐步提高,HBF-1活芽孢浓度为100μg/g时对棉铃虫的增效作用最大,使其死亡率提高了40.0%;HBF-1活芽孢浓度为50μg/g时对小菜蛾的增效作用最大,使其死亡率提高了47.0%。

苏云金杆菌HBF-1菌株在土壤中毒蛋白含量的ELISA检测

以苏云金芽孢杆菌HBF-1菌株中分离纯化的高特异性杀虫蛋白作为抗原,免疫新西兰白兔制备出多克隆抗体,其效价可达到16000。应用制备的特异性抗体建立了间接酶联免疫吸附测定法(ELISA),检测不同土壤样品中Bt毒蛋白含量。初步结果表明,该方法能够检测土壤中Bt毒蛋白的含量,因土壤理化特性及组成成分的不同,检测到的毒蛋白含量也略有不同,河沙中的蛋白检测量最低,只有12.53%;另一种沙壤混合物中检测量达到76.16%。

Isolation and Characterization of a Dichlorvos-Degrading Strain DDV-1 of Ochrobactrum sp.

The objective of this research was to isolate a dichlorvos (2,2-dichlorovinyl dimethyl phosphate)-degrading strain of Ochrobactrum sp., and determine its effectiveness in remediation of a dichlorvos-contaminated soil. A dichlorvos-degrading bacterium (strain DDV-1) was successfully isolated and identified as an Ochrobactrumsp. based on its 16S rDNA sequence analysis. Strain DDV-1 was able to utilize dichlorvos as a sole carbon source, and the optimal pH and temperature for its cell growth and degradation were 7.0 and 30 ℃, respectively. Also, the growth and degradation of strain DDV-1 showed the same response to dissolved oxygen. In addition, the soil degradation test indicated that in soil spiked with 100 mg L-1 or 500 mg L-1 dichlorvos and inoculated with 0.5% or 1.0% (v/v) strain DDV-1, complete degradation of dichlorvos could be achieved in 24 h. The present study showed that strain DDV-1 was a fast dichlorvos-degrading bacterium in soil. However, further research will be needed to clarify the degradation pathway and the properties of the key enzymes involved in its biodegradation.

Determination of conduction band edge characteristics of strained Si/Si1-xGex

The feature of conduction band （CB） of Tensile-Strained Si（TS-Si） on a relaxed Si1-xGex substrate is systematically investigated, including the number of equivalent CB edge energy extrema, CB energy minima, the position of the extremal point, and effective mass. Based on an analysis of symmetry under strain, the number of equivalent CB edge energy extrema is presented; Using the K.P method with the help of perturbation theory, dispersion relation near minima of CB bottom energy, derived from the linear deformation potential theory, is determined, from which the parameters, namely, the position of the extremal point, and the longitudinal and transverse masses （m1^＊ and mt^＊）are obtained.

Isolation and characterization of YNTC-1,a novel Alicyclobacillus sendaiensis strain

A heterotrophic acidothermophilic bacterial strain,YNTC-1,was isolated from an acidic hot spring in Tengchong,Yunan,China.YNTC-1 grows at pH value of 1.5-8.0 and temperature of 40-70℃,with optimal pH and temperature at 3.0 and 55℃,respectively.The cells of the strain are in shape of short rod,with 1.0-1.2μm in length and 0.7-0.8μm in diameter,and with distinct spores at both poles of each cell.The predominant fatty acids in cellular membrane of the strain are C18:1ω7c.16s rRNA gene analysis reveals that this strain is closely related to Alicyclobacillus sendaiensis,with over 99%sequence similarity.Based on phenotypic and genotypic analyses,YNTC-1 is identified as a member of A.sendaiensis.Considering some important morphological and biochemical differences between strain YNTC-1 and A.sendaiensis ATCC 27009T,YNTC-1 may be proposed to be a novel subspecies of A.sendaiensis.However,this viewpoint has to be confirmed by further studies.Co-bioleaching of pyrite and chalcopyrite with strain YN22,Sulfobacillus thermosulfidooxidans,shows that strain YNTC-1 has no evident influence on bioleaching rates of these two sulphide minerals.

Pressure influence on the Stark effect of impurity states in a strained wurtzite GaN/Al_xGa_(1-x)N heterojunction

A variational method is adopted to investigate the properties of shallow impurity states near the interface in a free strained wurtzite GaN/AlxGa1-xN heterojunction under hydrostatic pressure and external electric field by using a simplified coherent potential approximation. Considering the biaxial strain due to lattice mismatch or epitaxial growth and the uniaxial strains effects, we investigated the Stark energy shift led by an external electric field for impurity states as functions of pressure as well as the impurity position, A1 component and areal electron density. The numerical result shows that the binding energy near linearly increases with pressure from 0 to 10 GPa. It is also found that the binding energy as a function of the electric field perpendicular to the interface shows an un-linear red shift or a blue shift for different impurity positions. The effect of increasing x on blue shift is more significant than that on the red shift for the impurity in the channel near the interface. The pressure influence on the Stark shift is more obvious with increase of electric field and the distance between an impurity and the interface. The increase of pressure decreases the blue shift but increases the red shift.

Protein Characteristics and Field Efficacy of YN1-1, a Highly Virulent Strain of Bacillus thuringiensis

[Objective] This study aimed to investigate the biological characteristics of a Bacillus thuringiensis strain YNI-1, which has high virulence to Lepidoptera spp. [Method] The crystal protein of YNI-1 was analyzed by SDS-PAGE, and its indoor and field efficacy for Lepidoptera spp. was investigated. [Result] The parasporal crystal of YNI-1 has a diamond-like structure. The molecular weight of the original toxin protein is 136 kDa. After trypsin treatment, the original toxin protein was hy- drolyzed into active toxin protein with molecular weight of 63 kDa. For Plutella xy- Iostella and Pieris rapae, the indoor efficacy of B. thuringiensis was better than that of commercial B. thuringiensis （WP）. In view of field efficacy, rate of YNI-1 strain was higher than that of commercial B [Conelusion] YNI-1 strain has excellent development potential. the insects reduced thuringiensis （WP）.

Isolation and characteristics of Arthrobacter sp.strain CW-1 for biodegradation of PAEs

Isolation of new bacterial strains and recognition of their metabolic activities are highly desirable for sustainability of natural ecosystems. Biodegradation of dimethyl phthalate （DMP） under anoxic conditions has been shown to occur as a series of sequential steps using strain CW-1 isolated from digested sludge of Sibao Wastewater Treatment Plant in Hangzhou, China. The microbial colony on LB medium was yellowish, 3-5 mm in diameter, convex in the center, and embedded in mucous externally. The individual cells of strain CW-1 are irregular rods, measuring （0.6-0.7）×（0.9-1.0） pm, V-shaped, with clubbed ends, Gram positive and without any filaments. 16S rDNA （ 1438 bp） sequence analysis showed that the strain was related to Arthrobacter sp. CW-1 and can degrade PAEs utilizing nitrate as electron acceptor, but cannot mineralize DMP completely. The degradation pathway was recommended as： dimethyl phthalate （DMP）→monomethyl phthalate （MMP）--,phthalic acid （PA）. DMP biodegradation was a first order reaction with degradation rate constant of 0.3033 d 1 and half-life 2.25 d. The DMP conversion to PA by CW-1 could be described by using sequential kinetic model.

Crystallization of Nitrogenase MoFe Protein (NifB Av1) from a nifB Mutated Strain UW45 of Azotobacter vinelandii

Six hundred and 28 mg of NifB(-) Av1 was obtained by a chromatography twice on DE 52 columns and Sephacryl S-300 column from the crude extract (37 677 mg) of a nifB mutated strain UW45 of Azotobacter vinelandii Lipmann. The protein was almost homogeneous as determined by Coomassie staining of SDS gels. The analysis by SDS-PAGE showed that NifB(-)Av1 was similar to Av1 from wild-type strain of A. vinelandii (OP) in the kinds of subunits (alpha and beta subunit). When complemented with Av2, NifB(-)Av1 had hardly any H-reducing activity, but could be significantly activated by FeMoco extracted from Av1. Under a suitable condition for crystallization, short dark-brown rhombohedral crystals could be obtained from NifB(-)Av1. Both of the longest sides of the biggest crystal were 0.1 mm. The time of the formation of crystals and number, size, quality and shape of crystals obviously depended not only on the kinds and concentrations of the components in the precipitant solution, but also on the methods for crystallization and technical bias, etc. The preliminary results showed that the crystal seemed to be formed from NifB(-)Av1.

Misfit strains inducing voltage decay in LiMn_(y)Fe_(1-y)PO_(4)/C

LiMn_(y)Fe_(1-y)PO_(4) is considered a promising cathode material for next-generation lithium-ion batteries(LIBs) due to its high energy density and low cost. Its energy density degradation is often ascribed to the capacity loss during cycling. However, in this study, we find that the energy density degradation mainly roots in voltage decay. We have synthesized a series of LiMn_(y)Fe_(1-y)PO_(4) /C(0.5 ≤ y ≤ 0.8) and find this voltage decay is correlated with the Mn content. A high amount Mn leads to a heavier voltage decay.In-situ X-ray diffraction(XRD) and high-resolution transmission electron microscopy(HRTEM) reveal the nature of this effect, which show a mismatch along the b-axis of-2.68%(charge) and +3.4%(discharge), a volume misfit of-4.41%(charge) and +4.54%(discharge) between Li_(x)Mn_(y)Fe_(1-y)PO_(4) and Mn_(y)Fe_(1-y)PO_(4) during phase transitions. The resultant misfit strains during Li+insertion compared to extraction result in structural degradations, such as amorphization and impurity(Mn F3) accumulation after cycling. The voltage decay can be alleviated by kinetic relaxations and recovered by a wild reannealing. This work demonstrates effective strategies to improve the energy density and cycling performance of LiMn_(y)Fe_(1-y)PO_(4) /C,providing good references for other LIB cathodes, such as the Li-rich cathodes.

C^1 natural element method for strain gradient linear elasticity and its application to microstructures

C^1 natural element method （C^1 NEM） is applied to strain gradient linear elasticity, and size effects on mi crostructures are analyzed. The shape functions in C^1 NEM are built upon the natural neighbor interpolation （NNI）, with interpolation realized to nodal function and nodal gradient values, so that the essential boundary conditions （EBCs） can be imposed directly in a Galerkin scheme for partial differential equations （PDEs）. In the present paper, C^1 NEM for strain gradient linear elasticity is constructed, and sev- eral typical examples which have analytical solutions are presented to illustrate the effectiveness of the constructed method. In its application to microstructures, the size effects of bending stiffness and stress concentration factor （SCF） are studied for microspeciem and microgripper, respectively. It is observed that the size effects become rather strong when the width of spring for microgripper, the radius of circular perforation and the long axis of elliptical perforation for microspeciem come close to the material characteristic length scales. For the U-shaped notch, the size effects decline obviously with increasing notch radius, and decline mildly with increasing length of notch.

1株植物乳杆菌的生物学特性及体外抑菌活性研究

【目的】试验旨在研究植物乳杆菌GX20200417-1菌株的生物学特性及体外抑菌活性,探讨其在生产中应用的可能性。【方法】将植物乳杆菌GX20200417-1菌株接种至不同pH和含不同浓度胆盐的PBS,以及人工胃肠液中,使用菌落计数分析其对酸、胆盐和人工胃肠液的耐受性。使用牛津杯法检测GX20200417-1菌株对大肠杆菌、金黄色葡萄球菌及沙门氏菌的抑菌能力;通过与霉菌毒素共培养后使用ELISA方法研究GX20200417-1菌株对霉菌毒素的降解能力,并饲喂小鼠进行安全性试验。【结果】植物乳杆菌GX20200417-1菌株能够耐受pH 2.0及0.3%胆盐,并在人工胃肠液中有至少1×10^(4) CFU/mL的活菌数;GX20200417-1菌株发酵上清液对大肠杆菌、沙门氏菌、金黄色葡萄球菌均有明显的抑制作用,对玉米赤霉素及黄曲霉毒素均有降解作用,但对呕吐毒素无降解作用;灌服GX20200417-1菌株后小鼠安全、无毒副作用。【结论】植物乳杆菌GX20200417-1菌株具有优良的益生特性,在畜禽生产中有一定的开发潜力。

Isolation and Identification of a Specific cDNA Mapping to the Bam HI-I2 and -LFragments within the Inverted Repeats ofUnique Long Re-gion (IRL) in the Genom e ofMarek′s Disease Herpesvirus (MDV) Oncogenic Strain Beijing-1

Objective\ To understand the transcription of BamHI L DNA fragment from genome of strong virulent GA strain of Marek′s disease herpesvirus (MDV) in lymphoblastoid tumor tissue induced by oncogenic strain Beijing 1 (a specific local strain in China) of MDV. Methods\ Two oligonucleotide primers were synthesized according to the reported sequence of \%meq\% gene an ideal oncogenic candidate and our previously determined sequence of BamHI L fragment of Marek′s disease herpesvirus (MDV), respectively. Reverse transcriptase PCR(RT PCR) assay was performed by using these primers and the mRNA as a template which was isolated from visceral lymphoblastoid tumors obtained from chickens artificially infected with strain Beijing 1 of oncogenic MDV. Southern blot molecular hybridization was further carried out to detect the product of RT PCR with digoxigenin labeled nucleotide probe from BamHI I2 and L fragment in the gene library of MDV strain GA, respectively. Results\ Two probes could simultaneously hybridize this cDNA amplified by RT PCR with a length of about 730 bp. Conclusion\ It is suggested that \%meq\% transcription could extend from the right hand end of BamHI I2 to the adjacent BamHI L, and the BamHI L region was likely to be transcribed in MDV induced lymphoblastoid tumors.