蛹虫草（Cordceps militaris）无性型的多型现象

在萨氏琼脂和ＰＤＡ上,蛹虫草Ｃｏｒｄｙｃｅｐｓ ｍｉｌｉｔｅｒｉｓ（Ｖｕｉｌｌ）．Ｆｒ无性型,蛹草拟青霉Ｐａｅｃｉｌｏｍｙｃｅｓ ｍｉｌｉｔａｒｉｓ（Ｋｏｂ）．Ｂｒ＆Ｓｍ．的一些单孢子株可自发产生突变,基于多型现象及其它形态特征可分为三种类型：（１）具野生型菌株特征,产孢结构拟青霉型（Ｐａｅｃｉｌｏｍｙｃｅｓ－ｔｙｐｅ）,稳定,菌落通常不自发产生角变,大多数单孢了株属此类群。（２）属此类群的单孢子     

防治哈密瓜疫霉病抗生素产生菌的鉴定

从乌鲁木齐郊区土壤中分离到一株拮抗性放线菌,编号为Ｍ＿２。通过形态、培养特征、生理生化特性及细胞壁组分分析等研究,鉴定为链霉菌属的一个新亚种,定名为萨拉赛链霉菌乌鲁木齐亚种（Ｓｔｒｅｐｔｏｍｙｃｅｓｓａｒａｃｃｔｉｃｕｓｖａｒ．Ｕｒｕｍｕｑｉｅｎｓｅｎ．Ｖａｒ）。     

对“番泻甙”有代谢能力的几种肠内有益菌的分离和比较

本实验共分离到３属４种４２株肠内有益菌。上述菌株接种于１．０％“番泻甙”（Ｓｅｎｎｏｓｉｄｅｓ）Ｇａｍ ｂｒｏｔｈ中的培养结果表明,“番泻甙”对这些菌朱的增殖没有影响;并应用ＨＰＬＣ（高效液相色谱仪,直线梯度法）检测出４株具有“番泻甙”代谢能力的细菌,其中Ｂｉｆｉｄｏｂａｃｔｅｒｉｕｍ ｂｒｅｖｅ２株、ＢＢｉｆｉｄｏｂａｃｔｅｒｉｕｍ ｌｏｇｎｕｍ１株、Ｅｎｔｅｒｏｃｏｃｃｕｓ ｆｅａｃａｌｉｓａ     

新生儿颊粘膜定植菌株的拮抗性研究

本文分离在新生儿颊粘膜上皮细胞表面形成微菌落、且初代培养时菌落较纯的１５株ａ溶血细菌,进行对Ｂ链球菌、金黄色葡萄球菌、绿脓杆菌、大肠杆菌４种共７株菌的体外拮抗实验。１５株菌中包括８株ａＳｔｒｅｐ．,其中Ｓｔｒｅｐ．ｍｉｔｉｓ４株,Ｓｔｒｅｐ．ｏｒａｌｉｓ２株、Ｓｔｒｅｐ．Ｓａｌｉｖ．Ｓａｌｉｖａｒｉｕｓ１株、Ｓｔｒｅｐ．ｉｎｔｅｒｍｅｄｉｕｓ１株;ＬＣ．ｌａｃｔｉｓ．ｃｒｅｍｏｒｉｓ５株、Ｇｅｍｅｌａｍｏｒｂｉｌｏｒｕｍ１株、Ｇｅｍｅｌａｈａｅｍｏｌｙｓａｎｓ１株。结果约６０％（９／１５）的颊粘膜定植株对两株及两株以上的病原菌株或阴性杆菌株有拮抗作用,只对１株菌有损坏抗作用的ａ溶血菌４株,完全无拮抗作用的菌株２株;ａＳｔｒｅｐ．、ＬＣ．ｌａｃｔｉｓ．ｃｒｅｍｏｒｉｓ的拮抗作用较强;拮抗作用的有无、强弱有很强的菌株特异性     

烟草花叶病毒（普通株中国分离物）及其弱毒苗—N14（番茄株）组织 …

用双脱氧未端经终止法对侵染性烟草共现毒普通株中国分离物（ＴＭＶ－ｖｉｒｌｇａｒ,Ｃｈｉｎｅｓｅ ｌｓｏｂｌａｔｅ,ＴＭＶ－Ｃｖ）和番茄株弱毒轩ＴＭＶ－Ｎ１４（Ａｔｔｅｎｕａｔｅｄ ＴＭＶ ｖａｃｃｉｎｅ ｓｔｒａｉｎ）基因组ｃＤＮＡｓ的核苷酸全序列进行了测定,并分析和比较了其基因组的结构和特征。结果表明：普通株基因组（Ｇｅｎｂａｎｋ接收号：ＡＦ１６５１９０）为６３９５个核苷酸：４个功能性开放阅读框     

耐温酵母与酿酒酵母的属间融合及融合株的高温乙醇发酵

利用原生质体融合技术进行耐温的克鲁维酵母（Ｋｌｕｙｖｅｒｏｍｙｃｅｓ Ｙ０３４）与酿酒酵母（Ｓａｃｃｈａｒｏｍｙｃｅｓ ｃｅｒｅｕｉｓｉａｅ Ａ００１） 的属间融合,获得属间隔合子ＡＹ０６８。该融合株在４５℃下进行高温乙酵发酵,结果表明融合株表达了双亲耐温和产酒率高的特性。通过正交试验优化培养基成分,表明蛋东用量对菌体热抗性差异显著。比较了不同温度条件下,菌体生物量、糖利用率、ｐＨ因素与酒精产率的     

苏云金芽孢杆菌的电穿孔及其工程菌的构建

本文对苏芸金芽孢杆菌 (Ｂａｃｉｌｌｕｓｔｈｕｒｉｎｇｉｅｎｓｉｓ,Ｂｔ)和蜡状芽孢杆菌 (Ｂａｃｉｌｌｕｓｃｅｒｅｕｓ,Ｂｃ)等部分菌株的电穿孔转化进行了研究 ,主要从电穿孔的供体质粒和受体菌株等方面讨论了各种因素对该方法的影响。同时利用电穿孔方法对部分Ｂｔ的高效野生株进行遗传改良 ,希望获得含有ｃｒｙ1Ａｃ和ｃｒｙ1Ｃ高效基因组合的对鳞翅目棉铃虫、甜菜夜蛾都有效的广谱工程株。利用质粒 ｐＳＢ1 40 2 (ｃｒｙ1Ｃ) ,ｐＡＭＹ(ｃｒｙ1Ａｃ) ,ｐＮＱ1 2 2 (Ｃｍｒ)对所有的供试菌株进行电穿孔转化 ,不同菌株表现出不同的转…     

12株酵母菌的亲缘关系分析

克隆了９株假线酵母和１株克鲁维酵母的２５ＳｒＤＮＡ片段,测定其５′端部分苷酸序列与报道的Ｃａｎｄｉｄａａｌｂｉｃａｎｓ及Ｓａｃｃｈａｒｏｍｙｃｅｓｃｅｒｅｖｉｓｉａｅ２５ＳｒＤＮＡ相应区域的核苷酸序列比较,采用ｎｅｉｇｈｂｏｒ－ｊｏｉｎｉｎｇ和ｂｏｏｔ－ｓｔｒａｐ法分析并绘制系统树,结果提示ＣａｎｄｉｄａｋｅｆｙｒＣＢＳ８３４与Ｋｌｕｙｖｅｒｏｍｙｃｅｓ ｃｉｃｅｒｉｓｐｏｒｕｓＣＢＳ４８５７亲缘     

拮抗菌BS—98分泌抗菌蛋白的条件及其发酵液特性

由本室分离得到一株强烈抑制芦笋茎枯病等植物病原真菌的拮抗菌ＢＳ—９８菌株（Ｂａｃｉｌｌｕｓｓｕｂｔｉｌｉｓ）。用环柱法检测该菌株的抗菌活性表明,该菌株除抑制芦笋茎枯病菌ＰｈｏｍａａｓｐａｒａｇｉＳａｃｃ外,对小麦赤霉病菌（Ｆｕｓａｒｉｕｍｇｒａｍｉｎｅａｒｕｍ）,棉花枯萎病菌（Ｆｕｓａｒｉｕｍｏｘｙｓｐｏｒｕｍｆｓｐ．Ｖａｓｉｎｆｅｃｔｕｍ）、棉花黄萎病菌（Ｖｅｒｔｉｃｉｌｌｕｍａｌｂｏ—ａｔｒｕｍ）、黄瓜灰霉病菌（Ｂｏｔｒｙｔｉ     

球形红杆菌L2的生物学特性及其应用

从淀粉废水中分离获得一株光合细菌,经形态特征,培养特征,生理生化特征及Ｇ＋Ｃｍｏｌ％含量等生物学特性分析,确定为球形红杆菌（Ｒｈｏｄｏｂａｃｔｅｒｓｐｈａｅｒｏｉｄｅｓ）Ｌ２。该菌应用于淀粉废水处理,ＣＯＤ去除率达９５．７％发酵产类胡萝卜素,产量达２９５ｍｇ／Ｌ;作为饲料添加剂进行肉鸡饲喂,增重１６．４０％。     

Mechanical behaviour of in-situ chondrocytes subjected to different loading rates: a finite element study

Experimental findings indicate that in-situ chondrocytes die readily following impact loading, but remain essentially unaffected at low (non-impact) strain rates. This study was aimed at identifying possible causes for cell death in impact loading by quantifying chondrocyte mechanics when cartilage was subjected to a 5% nominal tissue strain at different strain rates. Multi-scale modelling techniques were used to simulate cartilage tissue and the corresponding chondrocytes residing in the tissue. Chondrocytes were modelled by accounting for the cell membrane, pericellular matrix and pericellular capsule. The results suggest that cell deformations, cell fluid pressures and fluid flow velocity through cells are highest at the highest (impact) strain rate, but they do not reach damaging levels. Tangential strain rates of the cell membrane were highest at the highest strain rate and were observed primarily in superficial tissue cells. Since cell death following impact loading occurs primarily in superficial zone cells, we speculate that cell death in impact loading is caused by the high tangential strain rates in the membrane of superficial zone cells causing membrane rupture and loss of cell content and integrity.     

Dehydration strain avoidance and tolerance in plant cold hardiness

Cell strain during freezing is typically characterized by either a measure of cell volume contraction or a measure of the fraction of cell water frozen. If the measure of strain at the killing temperature increases during cold acclimation, it is concluded that hardiness is controlled by strain tolerance, and if the measure of strain does not increase during cold acclimation it is concluded that hardiness is controlled by strain avoidance. It is demonstrated that the measure of cell volume contraction is not mathematically equivalent to the measure of the fraction of water frozen. Thus the conclusion regarding the relative role of avoidance and tolerance in frost hardiness depends upon the choice of strain measurement. The parameters determining the two measures of strain indicate that if cell injury is related to membrane area contraction or expansion then the measure of cell volume contraction is likely to be the better measure of strain; however, if cell injury is related to solution effects, the measure of the fraction of water frozen is likely to be the better measure of strain. In addition, the temperature dependence of each strain measure is derived to aid in the visualization of the freezing process, and to accommodate calculation of the measures of strain from data obtained at above freezing temperatures.     

Comparison of cellular strain with applied substrate strain in vitro

Strain magnitudes within tenocytes undergoing substrate tensile strain are not well defined. It was hypothesized that strain magnitudes at the cellular level would reflect those of the applied substrate (equibiaxial or uniaxial) strain. A vacuum-operated device was used to apply equibiaxial or uniaxial tension to a flexible substrate upon which tenocytes were cultured in monolayer. Images of tenocytes labeled with Fura-2, to detect free intracellular calcium ions, and MitoFluor Green, to detect mitochondria, were taken prior to strain and for 20 min during application of static strain. A custom-written, texture correlation program computed strain magnitudes in the cell based on the change in pixel pattern displacements between images of non-strained and strained cells. On average, cellular strain was approximately 37+/-8% and 63+/-11% of the applied equibiaxial and uniaxial substrate strain, respectively. The largest cell strains were detected in cells oriented parallel to the direction of applied uniaxial tensile strain. However, strain magnitudes within a cell were heterogeneous. The variance in strain magnitude within and among tenocytes is dependent on cell orientation, cell stiffness, cytoskeleton organization, subcellular organelles, or placement and type of cell-substrate contacts. Results of the present study indicate that cultured tenocytes experience a moderate fraction of the applied substrate strain.     

细胞分裂蛋白编码基因的敲除对丙酮丁醇梭菌溶剂合成与细胞形态的影响

丙酮丁醇梭菌是生物丁醇合成的重要菌株,近年来,研究者们利用基因编辑等技术对其进行菌株改造。通过对丙酮丁醇梭菌中3个细胞分裂蛋白(RodA、DivIVA、DivIB)编码基因(cac1251、cac2118、cac2125)进行敲除,发现cac2118敲除菌株的细胞在产溶剂期为球状形态,细胞变小,ABE发酵的丁醇得率为0.19 g/g,与野生型相比提高了5.6%。cac1251敲除菌株的葡萄糖消耗量和丁醇产量与野生型相比降低了33.9%和56.3%,分别为47.3 g/L和5.6 g/L。cac1251和cac2125的敲除对细胞生长有显著影响,菌体浓度最大值与野生型相比分别降低了40.4%和38.3%。研究表明细胞分裂蛋白DivIVA对细胞的形态和大小调控起重要作用;细胞分裂蛋白RodA和DivIB调控细胞分裂进程,进而影响细胞生长和溶剂合成进程。     

Cyclic strain induces mouse embryonic stem cell differentiation into vascular smooth muscle cells by activating PDGF receptor beta

Embryonic stem (ES) cells are exposed to fluid-mechanical forces, such as cyclic strain and shear stress, during the process of embryonic development but much remains to be elucidated concerning the role of fluid-mechanical forces in ES cell differentiation. Here, we show that cyclic strain induces vascular smooth muscle cell (VSMC) differentiation in murine ES cells. Flk-1-positive (Flk-1+) ES cells seeded on flexible silicone membranes were subjected to controlled levels of cyclic strain and examined for changes in cell proliferation and expression of various cell lineage markers. When exposed to cyclic strain (4-12% strain, 1 Hz, 24 h), the Flk-1+ ES cells significantly increased in cell number and became oriented perpendicular to the direction of strain. There were dose-dependent increases in the VSMC markers smooth muscle alpha-actin and smooth muscle-myosin heavy chain at both the protein and gene expression level in response to cyclic strain, whereas expression of the vascular endothelial cell marker Flk-1 decreased, and there were no changes in the other endothelial cell markers (Flt-1, VE-cadherin, and platelet endothelial cell adhesion molecule 1), the blood cell marker CD3, or the epithelial marker keratin. The PDGF receptor beta (PDGFR beta) kinase inhibitor AG-1296 completely blocked the cyclic strain-induced increase in cell number and VSMC marker expression. Cyclic strain immediately caused phosphorylation of PDGFR beta in a dose-dependent manner, but neutralizing antibody against PDGF-BB did not block the PDGFR beta phosphorylation. These results suggest that cyclic strain activates PDGFR beta in a ligand-independent manner and that the activation plays a critical role in VSMC differentiation from Flk-1+ ES cells.     

In Vitro Experimental Study for the Determination of Cellular Axial Strain Threshold and Preferential Axial Strain from Cell Orientation Behavior in a Non-uniform Deformation Field

Cells within connective tissues are routinely subjected to a wide range of non-uniform mechanical loads that regulate many cell behaviors. In the present study, the relationship between cell orientation angle and strain value of the membrane was comprehensively investigated using an inhomogeneous strain field. Additionally, the cellular axial strain threshold, which corresponds to the launching of cell reorientation response, was elucidated. Human bone marrow mesenchymal stem cells were used for these experiments. In this study, an inhomogeneous strain distribution was easily created by removing one side holes of an elastic chamber in a commonly used uniaxial stretching device. The strains of 2D stretched membranes were quantified on a position-by-position basis using the digital image correlation method. The normal strain in the direction of stretch was changed continuously from 2.0 to 15.0 %. A 3D histogram of the cell frequency, which was correlated with the cell orientation angle and normal strain of the membrane, made it possible to determine the axial strain threshold accurately. The value of the axial strain threshold was 4.4 ± 0.3 %, which was reasonable compared with previous studies based on cyclic uniaxial stretch stimulation (homogeneous strain field). Additionally, preferential axial strain of cells, which was a cell property firstly introduced, was also achieved and the value was ?2.0 ± 0.1 %. This study is novel in three respects: (i) it precisely and easily determined the axial strain threshold of cells; (ii) it is the first to suggest preferential axial strain of cells; and (iii) it methodically investigated cell behavior in an inhomogeneous strain field.     

Carboxyl-terminal protease regulates Brucella suis morphology in culture and persistence in macrophages and mice

The putative carboxyl-terminal processing protease (CtpA) of Brucella suis 1330 is a member of a novel family of endoproteases involved in the maturation of proteins destined for the cell envelope. The B. suis CtpA protein shared up to 77% homology with CtpA proteins of other bacteria. A CtpA-deficient Brucella strain (1330DeltactpA), generated by allelic exchange, produced smaller colonies on enriched agar plates and exhibited a 50% decrease in growth rate in enriched liquid medium and no growth in salt-free enriched medium compared to the wild-type strain 1330 or the ctpA-complemented strain 1330DeltactpA[pBBctpA]. Electron microscopy revealed that in contrast to the native coccobacillus shape of wild-type strain 1330, strain 1330DeltactpA possessed a spherical shape, an increased cell diameter, and cell membranes partially dissociated from the cell envelope. In the J774 mouse macrophage cell line, 24 h after infection, the CFU of the strain 1330DeltactpA declined by approximately 3 log(10) CFU relative to wild-type strain 1330. Nine weeks after intraperitoneal inoculation of BALB/c mice, strain 1330DeltactpA had cleared from spleens but strain 1330 was still present. These observations suggest that the CtpA activity is necessary for the intracellular survival of B. suis. Relative to the saline-injected mice, strain 1330DeltactpA-vaccinated mice exhibited 4 to 5 log(10) CFU of protection against challenge with virulent B. abortus strain 2308 or B. suis strain 1330 but no protection against B. melitensis strain 16 M. This is the first report correlating a CtpA deficiency with cell morphology and attenuation of B. suis.     

Altered cell tropism and cytopathicity of feline immunodeficiency viruses in two different feline CD4-positive, CD8-negative cell lines.

Two interleukin-2-dependent feline CD4-positive and CD8-negative cell lines, MYA-1 and the newly established FeL-039, were used as host cells for infection with feline immunodeficiency virus (FIV). All FIV strains used, the Petaluma strain and several new isolates, were highly cytopathic to MYA-1. In contrast, the kinetics of FIV replication in FeL-039 differed greatly depending on the strain tested, i.e., noninfectious strain, highly cytopathic strain, and less cytopathic strain producing a persistent state for a long period. It appears, therefore, that cell tropism for FIV differed with each FIV strain tested even in T-cell lines showing similar cell surface phenotypes. Cytopathicity of FIV is evidently due to both the FIV strain and the host T cell.     

Study of selected characteristics of theChlamydomonas reinhardii strains with altered sensitivity to UV radiation

Selected characteristics and streptomycin resistance were studied in a UV radiation sensitive (UVS1) and a UV radiation resistant (UVR1) strains, and the data were compared with results obtained with an original type strain. A partial prolongation of the cell cycle in the UVR1 strain as compared with the original type strain could be observed in studying cell volume growth, cell numbers, DNA, RNA and protein synthesis during the synchronous cycle. Under these conditions, the UVS1 strain behaved as a temperature sensitive cell cycle mutant. In inducing streptomycin resistant mutants, the highest frequencies in various doses were recorded in the UVS1 strain.     

Improvement of the cell volume ofCandida blankii through protoplast fusion

Summary The yeastCandida blankii ESP-94, capable of utilizing xylose as substrate, was isolated for the production of single-cell protein (SCP) on bagasse hydrolysates. However, the small cell volume of strain ESP-94 would complicate harvesting of the cells during a continuous fermentation process. Auxotrophic mutants of strain ESP-94 were generated and intraspecific protoplast fusion experiments performed in an attempt to increase the cell volume of strain ESP-94. The fusion products were characterised with respect to cell volume, DNA content and genetic stability. Six genetically stable fusants with bigger cell volumes and higher DNA contents were obtained. One such fusant, fusant F17, had a cell volume 3-times that of strain ESP-94, while exhibiting similar growth rates to strain ESP-94 ond-xylose as carbon source.