嗜树木甲烷短杆菌和甲酸甲烷杆菌的分离和特性

从我国沼气池污泥样品中,采用改良的亨氏操作技术,分离出TC713和TC708两株不运动、革兰氏染色阴性、不形成芽孢的杆菌。TC713菌株呈短杆状,往往两个相连成双杆菌,个别呈链杆状,菌落圆形透明。TC708菌株培养后期呈长杆状,弯曲,菌落圆形,周边呈现丝状。 两菌株均只能利用H2／CO2作为碳源和能源,不能利用CH,COONa、CH,NH。、CH,OH。利用甲酸较慢,且利用率不高。在培养液中分别加入酵母膏、瘤胃液或酪素水解物均能刺激1c713菌株的生长,但该菌株不需要外源辅酶M。Tc713和Tc708菌株生长最适温度分别为35℃和35—40℃在45℃生长不良。适宜生长的pH值分别为6．5—8．5和6．8—9．20在含有o．I％酵母膏的培养液中,以H,／∞,为碳源和能源,37℃下振荡培养,其菌数倍增时间分别为6—7小时和8—10．5小时。Tc713菌株经荧光免疫测定,仅对甲酸甲烷杆菌抗体有微弱的反应。DNA中G+c克分子含量为27．83士0．26％。根据Tc713和Tc708两菌株的性状,分别确定为嗜树木甲烷短杆菌(Methanobrevibacter arboriphilus)和甲酸甲烷杆菌(Methano-bacterium formicicum)。     

甲烷短杆菌HX菌株的分离和特性

本文描述了从上海沼气池污泥中分离出的一株产甲烷菌。细胞为柳叶刀状到卵圆状的短杆菌,革兰氏阳性,0．5～0.8×1．0—1．2μm,单个或威对存在。滚管菌落很小,半透明,灰白色,近似圆形,边缘完整。反射荧光显徽镜检查呈鲜艳的蓝绿色荧光。分离物利用H z,／CO或者甲酸生长和产甲烷。不需要外加2一甲基丁酸(2一mcthylbu‘yrate)、辅酶M或者氨基酸。细胞生长不需要酵母膏、胰解酪蛋白、癌胃蔽和乙酸。但是,酵母膏、胰解酪蛋白和瘤胃液对生长和产甲烷有刺激作用。分离物在有胆盐存在的情况下不生长。生长和产甲烷的虽适温度均为q0℃。最适pH为7．6,生长和产甲烷的pH范围为6．9—8．60在含o．2 5％甲酸、0．2％酵母膏和胰解酪蛋白的培养液中,最低倍增时间为Io小时·DNA的G+c含量为31．I 3mo／~o该菌株具有甲烷短杆菌所特有的形态和DNA的G+c含量。因此,暂将它定为史氏甲烷短杆菌L-IX菌株(Metha~obrembaeter smitl~ii strain HX)o其真正的分类地位,需根据与已确定的(代表不同物种的)不同菌株产甲烷菌的抗血清发生的间接免疫荧光反应来决定。     

一种甲烷短杆菌的克林达霉素抗性突变型

在含克林达霉素10,ug／ml(无乙酸钠)的Balch 1号培养基中重复转种后,从甲烷短杆菌Hx菌株中选择出稳定的抗克林述霉素的自然突变株。在含克林达霉素的斜面上,抗性突变株细胞连成长链。在含克林述霉素的滚管中,抗性菌落的颤色为深灰色。在有和无克林达霉素的培养基中培养21天后,抗性突变株的甲烷产量相差不大。突变株对红霉素和卡那霉素呈交叉抗性。     

史氏甲烷短杆菌的分离和生理生化特性

采用改良的Hungate厌氧操作技术,从成都市狮子山污泥富集样品中分离到H—13菌株。该菌株革兰氏反应弱阳性,不运动、不形成芽孢。H-13菌株为两端略呈钝形的短杆菌,在H2／CO2及甲酸基质上一般成对出现连成双杆菌,偶见链状细胞。菌落圆形,半透明,微凸起,稍带浅黄色。 H一1 3菌株可利用H：／co;和甲酸作为碳源和能源,不能利用CH3COONa,(cH,)3N及cH,0H。酵母膏、胰化酪蛋白能刺激该菌株的生长。最适生长pH为7.3—7.5。在含0 2％酵母膏、0．1％胰化酪蛋白MA培养基中,以H,／co z作为碳源和能源,37℃、50rpm振荡培养,菌数倍增时间为5.7小时。根据电镜形态学分析及生理学性状研究,H-13菌株与史氏甲烷短杆菌(Meshnnobreribacter smithii)标准菌株极为相似,初步定为史氏甲烷短杆菌。     

絮凝方法收集产氨短杆菌MA-2、黄色短杆菌MA-3条件的优化

采用壳聚糖作絮凝剂收集富含延胡索酸酶活力的产氨短杆菌MA-2、黄色短杆菌MA-3。研究了絮凝剂加入量及加入时混合方式与时间等因素对延胡索酸酶活力及分离效果的影响,并对壳聚糖絮凝收集产氨短杆菌MA-2、黄色短杆菌MA-3的过程进行了初步分析。     

短乳杆菌葡萄糖异构酶固定化的研究

采用离子交换树脂ＤＥＡＥ纤维素对短乳杆菌葡萄糖异构酶进行固定化,并用固定化细胞使葡萄糖异构化为果糖,研究了制备固定化细胞最佳条件,而且与戊二醛交联法,海藻酸钙包埋法作了比较。还研究了固定化细胞的性质及连续转化的最佳条件,用ＤＥＡＥ纤维素固定化具有酶活力高,回收率高,机械强度好,成本低等优点。     

短棒状杆菌体外抑菌作用的初步探讨

探讨短棒状杆菌体外用药的抑菌效果,为临床应用奠定基础。将短棒状杆菌稀释成6.0×109/mL的菌悬液,分别与已传代扩增的1.0×102/mL的供试菌菌悬液等量混合,再接种至培养皿中,计算菌落总数。同时设生理盐水、CP滤液和灭活CP的对照试验。大肠埃希菌、金黄色葡萄球菌、淋病奈瑟菌、铜绿假单胞菌、乙型溶血性链球菌较对照组同比长菌量明显减少,T检验与对照组均有显著性差异;白假丝酵母菌、黑曲霉与对照组长菌量均无显著性差异。短棒状杆菌外用给药对某些细菌具有一定的抑菌效果,对白假丝酵母菌及黑曲霉菌无抑菌作用。     

嗜热甲酸甲烷杆菌602B_3与拟杆菌5G—102的混合培养

研究了嗜热甲酸甲烷杆菌(Methanobacterium thermoformicicum)602B_3与发酵糖蜜产生C0_2和H_2的拟杆菌(Bacteroides sp.)5G-102的人工可配伍性。确定了它们混合培养的适宜培养基组分为(g/L):CaC0_3 50.0,NaHCO_3 4.0,Na_2S 0.16,NH_4Cl 1.07,K_2HPO_4 1.04,MgCl_2 0.19,糖蜜40(V/V),自来水IL,起始pH 6.8～7.2。混合培养物在60℃培养48h,甲烷产量达到最高,约45mmol/L。人工混合培养成功为进一步研究其在提高石油采收率工艺中的可用性提供了前提。     

固定化产氨短杆菌MA-2、黄色短杆菌MA-3反应动力学的研究

多年来虽然有不少学者对固定化细胞生产Ｌ 苹果酸的方法进行过探讨[1～ 6] ,但对过程动力学的研究报道并不多见[2 ,7] ,在富马酸铵转化体系中的表观动力学及本征动力学模型还未见报道 ,本文对富马酸铵转化体系中固定化产氨短杆菌ＭＡ 2、黄色短杆菌ＭＡ 3细胞的动力学进行了探讨 ,测定了两种固定化细胞的表观动力学常数 ,并进一步求解了相应的本征动力学常数 ,这一结果便于从理论上指导富马酸铵转化过程的工业化生产。1　材料和方法1 1　试剂富马酸 ,工业级 ,苏州合成化工厂 ,碳酸钙 ,工业级 ,泗联化工厂。1 2　菌株本文所用的菌株是由我院…     

Interactions between anaerobic cellulolytic bacteria and fungi in the presence of Methanobrevibacter smithii

A mixed inoculum of cellulolytic rumen bacteria depressed straw degradation by a mixed culture of cellulolytic fungi grown in the presence of Methanobrevibacter smithii. The inhibitory effect appeared to be caused by Ruminococcus albus strain JI and R. flavefaciens strain 007. Ruminococcus albus strain J1 also depressed straw degradation by the fungi, but R. albus strain SY3 and three strains of Bacteroides (Fibrobacter) succinogenes tested showed little or no inhibitory activity. It seems that some ruminococci show competitive or antagonistic activity towards certain rumen fungi.     

中国人结肠癌nm23H1基因遗传不稳定性的研究

Techniques such as DNA extraction from paraffin-embedded tissues, polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP), ordinary silver stain, Envision immunohistochemistry and Leica-Qwin computer imaging techniques were used to study microsatellite instability (MSI) and loss of heterozygosity (LOH) of locus D17S396 at the 17th chromosome of Chinese patients and their influence on the expression of gene nm23H1, and to clarify the relationship between the genetic instability of gene nm23H1 and the development of colon cancer, which may provide experimental basis for clinical treatment. In our experiments, the frequency of MSI, LOH and nm23H1 protein reacted positive of 30 cases of colon cancer were 26.67%, 20.00% and 53.33% respectively. In tumor node metastasis (TNM) staging, the positive frequency of MSI (43.75%) and nm23H1 protein (81.25%) in stage I + II were more than those (MSI 7.14%, p < 0.05 and nm23H1 21.43%, p < 0.01) in stage III + IV, while the frequency of LOH (35.71%), which had a rising trend along with the Duke's staging increasing, was higher than that of LOH (6.25%, p < 0.05) in stage I + II. The positive frequency of nm23H1 protein in the group of tubular adenocarcinoma (60.00%) was distinctively higher than that in the group of mucoid adenocarcinoma (20.00%, p < 0.01), showing a rising trend along with the increase of the differentiation degree of tubular adenocarcinoma. Furthermore, the positive frequency of nm23H1 protein in MSI positive group was also higher than MSI negative group (p < 0.05). And there was no difference in nm23H1 protein expression analyzed by computer imaging techniques. The results of experiments indicated that both MSI and LOH controlled the development of sporadic colon cancer independently in different paths. LOH occurred mostly in the late period of sporadic colon cancer and endowed with it a high aggressive and poor prognosis. In contrast, MSI was an early period molecule marker of sporadic colon cancer. Increasing the amount of nm23H1 protein expression could effectively restrain colon cancer metastasis and improved prognosis of sporadic colon cancer patients.     

Laparoscopic-assisted colectomy in a patient with colon cancer after percutaneous endoscopic gastrostomy

ABSTRACT: BACKGROUND: A number of patients undergo percutaneous endoscopic gastrostomy (PEG) under various conditions. Open colectomy is usually performed for colon cancer in patients with PEG because the safety of the laparoscopic approach for such patients has not been established. However, if the laparoscopic approach is possible in patients with PEG, it will be less invasive and more helpful in rehabilitation into society. CASE PRESENTATION: We describe the case of a 64-year-old male with a T1 adenocarcinoma of the ascending colon 2 years after surgery for nasal cancer and PEG for dysphagia. The patient did not have any distant metastases or malignant tumors on preoperative computed tomography and positronemission tomography. He underwent laparoscopic-assisted colectomy (LAC) with lymph node dissection. No complications developed during or after the surgery. CONCLUSIONS: LAC could be a potential option for the treatment of colon cancer in patients who have undergone PEG. To our knowledge, this is the first recorded case of an ascending colon cancer treated with LAC under the condition of gastrostoma.     

Effect of coumarin on glucose uptake by anaerobic rumen fungi in the presence and absence of Methanobrevibacter smithii

The effect of coumarin (1,2 benzopyrone) on glucose utilisation by the anaerobic rumen fungi Neocallimastix frontalis and N. patriciarum has been compared with the effect of p-coumaric acid. Both compounds largely inhibited glucose utilisation by N. patriciarum strain Cx when present in the medium at a concentration of 2.5 mM, and had a similar effect on N. frontalis strain RE1 at 5 mM. Although in earlier studies co-culturing rumen fungi with Methanobrevibacter smithii enhanced resistance to ionophores, no comparable protective effect of M. smithii was found in the present study.     

Demonstration of the presence of G-proteins in hepatic microsomal fraction

The presence of G-proteins in isolated hepatic microsomal vesicles is demonstrated. The G-proteins were identified by their capacity to be ADP-ribosylated by cholera and pertussis toxins. Cholera toxin identified 42 and 45 kDa proteins, corresponding to alpha s-1 and alpha s-2, respectively. Pertussis toxin identified a 40 kDa protein corresponding to alpha i. The microsomal G-proteins are identical to the corresponding G proteins of the plasma membrane, but are present in different proportions; the microsomes have considerably less alpha s proteins than the plasma membrane.     

Characterization of a Heme-Dependent Catalase from Methanobrevibacter arboriphilus

Recently it was reported that methanogens of the genus Methanobrevibacter exhibit catalase activity. This was surprising, since Methanobrevibacter species belong to the order Methanobacteriales, which are known not to contain cytochromes and to lack the ability to synthesize heme. We report here that Methanobrevibacter arboriphilus strains AZ and DH1 contained catalase activity only when the growth medium was supplemented with hemin. The heme catalase was purified and characterized, and the encoding gene was cloned. The amino acid sequence of the catalase from the methanogens is most similar to that of Methanosarcina barkeri.     

The presence of a 33-40 KDa gastrin binding protein on human and mouse colon cancer

Human and mouse colon cancers have specific binding sites for gastrin and demonstrate a trophic response to gastrin. In the present study we used radiolabeled gastrin (2-17), to determine the molecular weight of gastrin binding proteins (receptors) on mouse and human colon cancers, by cross-linking methods. Crude membrane aliquots prepared from the tumors were radiolabeled with [125I]gastrin (2-17) +/- 1000 fold excess of unlabeled gastrin and cross-linked with 1 mM disuccinimidyl suberate. The cross-linked radiolabeled binding protein complexes were solubilized and subjected to sodium dodecyl sulfate polyacrylamide gel electrophoresis. The autoradiographs of the gels demonstrated the presence of a predominant band of approximately 33-40 KDa gastrin binding protein, that was specific for gastrin analogs. Our present findings thus indicate that specific gastrin binding proteins/gastrin receptors on colon cancers are primarily present as one band with a molecular mass of approximately 33-40 KDa and are specific for gastrin-like peptides.