桑粒肩天牛肠道纤维素分解细菌的分离和鉴定*

为研究天牛消化利用纤维素的机理,利用纤维素-刚果红琼脂培养基,从桑粒肩天牛(A.germari)幼虫中肠分离到一种兼性厌氧纤维素分解菌。菌落为白色圆形,边缘比较规则,周围溶纤维素透明圈直径一般可达10mm～20mm,细菌大小为0.5～0.8μm×1～3μm,革兰氏染色阳性,杆状,极生鞭毛,无芽孢。结合生化实验结果,初步鉴定该菌株为纤维单孢菌属(Cellulomonas)。     

用平板透明圈法测定细菌的苎麻脱胶活力

经过多年摸索,我们认为平板透明圈法对予测定细菌的苎麻脱胶活力,是一种较为快速和简便的方法,现将该方法介绍如下。 一、原理 把细菌培养在含果胶的平板培养基上,细菌若产生细胞外的果胶酶,则其菌落周围在用碘液处理平板后,即出现清晰的透明圈。如果     

亚麻微生物脱胶菌种的筛选与鉴定

在研究天然水沤法脱胶的过程中,通过初筛、复筛,从沤麻主生物期的沤麻液中筛选出两株茵落周围产生透明圈较大、脱胶酶活较高的菌株。通过形态观察,并对其多项生理、生化指标进行了分析研究,初步鉴定并命名为枯草芽孢杆菌A1和B1。初步加茵脱胶实验表明：枯草芽孢杆菌A1产生果胶酶、木聚糖酶,而不产生纤维素酶,脱胶周期为72小时;枯草芽孢杆茵B1产生果胶酶、木聚糖酶和纤维素酶,脱胶周期为50小时。     

几株解纤维素生防芽孢杆菌的分子鉴定及其抗逆促生特性分析

【目的】探究青藏高原解纤维素生防芽孢杆菌资源。【方法】采用BOX-PCR指纹图谱分析、gyr B基因及16S r RNA基因序列分析,对分离自青海互助北山桦树根围的5株芽孢杆菌进行分子鉴定;通过CMC法检测菌株降解纤维素活性;平板对峙法检测菌株拮抗病原真菌及病原细菌活性;检测菌株的耐盐性、低温适生性;测定菌株促种子萌发及幼苗生长特性。【结果】5株菌均鉴定为解淀粉芽孢杆菌Bacillus amyloliquefaciens;具有显著降解纤维素的特性,在CMC平板上形成纤维素降解透明圈直径≥20 mm;对油菜菌核病菌(Sclerotinia sclerotiorum)、瓜类枯萎病菌(Fusarium oxysporum)、水稻白叶枯病菌(Xanthomonas oryzae pv.oryzae)及植物梨火疫病菌(Erwinia amylovora)均有显著拮抗活性;菌株可在含Na Cl浓度为11%的LB平板上正常生长,在10°C低温条件下生长良好;菌株BS11、BS12菌悬液(细胞浓度106 CFU/m L)可促进水稻种子萌发及幼苗生长。【结论】5株B.amyloliquefaciens菌株为抗逆性强的、具有降解纤维素活性的生防芽孢杆菌,在青藏高原生态农业及畜牧产业中具有应用潜力。     

亚麻微生物脱胶优势菌的选育及其应用

从亚麻种植土壤与沤麻水中分离出96株能分解果胶的菌株。通过初筛和复筛获得4株果胶酶高产菌株。其中,在果胶平板培养基上生长速度快、产果胶酶活力高的12号菌株被确定为优势菌,经鉴定其为枯草芽孢杆菌。最适脱胶条件为：麻水比1：15,pH7．5,温度32～33℃,预培养的优势菌接种量3％。结果表明,采用优势菌的脱胶周期比对照缩短50％左右,而且麻的纤维质量明显得以改善。     

一株厌氧纤维素分解细菌的分离和鉴定

从猪粪、玉米秸作原料的甲烷发酵瓶中,分离到一株中温厌氧纤维素分解细菌。在纸浆纤维素琼脂滚管中的表层菌落为圆形,具有不规则边缘,深层菌落为扩散形。菌落白色或淡黄色,周围溶纤维素透明圈的直径一般可达10一30mm。细胞革兰氏染色阴性,稍弯杆状,0．6一0.8×2—5．5μm(活细胞),具有周生鞭毛,能运动。芽孢卵至球形、端生(有时次端生),直径1—1．2×1—1．5μm。最适生长温度35一40℃,最适pH7．0—7．5。DNA的G+C含量为35mol％(热变性中点方法)o该菌利用木聚糖、纤维二糖、淀粉、木糖、阿拉伯糖、葡萄糖、麦芽糖和七叶苷。用纤维素或葡萄糖发酵,产物有氢、二氧化碳、乙醇、乙酸、丁醇和丙酮酸。该菌株与c菌株十分相似“’,认为它们是同一个种。     

适于罗布麻生物脱胶的果胶酶产生菌分离筛选与表征

在青海柴达木盆地沤制的罗布麻表皮中分离得到两株适于罗布麻脱胶的高产果胶酶菌株,经形态、生理生化指标鉴证和16SrDNA菌种鉴定,确定一株为新的果胶酶产生菌琼氏不动杆菌（Acinetobacter junii）,一株为枯草芽孢杆菌（Bacillus subtilis）。水解圈实验得出前者H／C值（H／C为水解圈直径H与菌落直径C之比）为5,后者为3;经酶活力测定,在37℃下,琼氏不动杆菌（Acinetobacter junii）在11h达到产酶高峰（酶活力为103．2IU／mL）,枯草芽孢杆菌（Bacillus subtilis）培养至9h达到产酶高峰（酶活力为91．6IU／mL）,但前者最高酶活力比后者高12．5％;经脱胶实验得出两菌残胶率分别为18．47％和17．31％,对罗布麻生物脱胶有较好的适用性。     

麻微生物脱胶菌株初筛

采用遥瓶直接脱胶结合平板透明圈分离法,可有效分离出有一定脱胶能力的菌株,减少分离工作盲目性。我们获得的几株野生菌株,能在较长的时间内,将苎麻纤维脱胶至“白而软”。     

两株香蕉枯萎病拮抗细菌的筛选及抑菌机理

【目的】从发病蕉园中的健康香蕉根际筛选能有效抑制香蕉枯萎病病原菌生长的拮抗菌,进一步研究其抑菌机理。【方法】应用双层平板初筛和平板对峙实验复筛具有抑菌效果的拮抗菌;经生理生化试验、16S rRNA基因测序和特异引物扩增对拮抗菌进行鉴定;酸沉淀方法提取拮抗菌发酵液抑菌物质粗提液,基于比色法和HPLC测定粗提液对菌丝蛋白质含量、脂质过氧化、麦角甾醇和果胶酶活性的影响。【结果】筛选获得两株拮抗细菌H-2和H-7,初步鉴定为枯草芽孢杆菌和解淀粉芽孢杆菌,Gen Bank登录号分别为KX791428和KX791430;温室盆栽试验显示,两株拮抗菌对香蕉枯萎病的生防效率分别为59.1%和53.0%;H-2和H-7粗提液处理病原菌菌丝后,因脂质过氧化产生的丙二醛含量显著增加,分别达0.55μmol/L和0.48μmol/L;而蛋白含量、麦角甾醇含量和果胶酶活性均显著下降,其中H-2处理的抑制幅度更大,三项指标分别为0.15 mg/g、1.31 mg/g和0.008 7 U/m L,显著低于对照的0.25 mg/g、1.96 mg/g和0.035 U/m L。【结论】从健康香蕉根际筛选到两株拮抗细菌,两者可能通过增强病原菌菌丝的脂质过氧化和降低细胞代谢产物合成的方式抑制病原菌生长,可为两株拮抗菌的生防应用提供理论依据。     

亚麻纤维脱胶菌的筛选及脱胶效果研究

为筛选亚麻纤维脱胶菌株,从麻脱胶废水、废麻堆积物等7个含麻胶质样品中分离得到39株能分解果胶的菌株.采用水解圈法复筛选出8株果胶酶活性较高的菌株,经果胶酶、纤维素酶活性测定和菌体脱胶试验,最终确定8-1是优良的亚麻脱胶菌株,该菌株果胶酶活可达663.17 u/mL,而纤维素酶活仅为9.13 u/mL.菌株8-1经形态观察、Biolog菌种鉴定系统鉴定以及基于16S rDNA序列构建的系统进化树分析为一株芽孢杆菌.     

Investigation of the mechanism of temperature sensitivity of the electroreceptors of ampullae of lorenzini

In experiments on Black Sea skates (Raja clavata), the potential of the receptor epithelium of the ampullae of Lorenzini and spike activity of single nerve fibers connected to them were investigated during electrical and temperature stimulation. Usually the potential within the canal was between 0 and –2 mV, and the input resistance of the ampulla 250–400 k. Heating of the region of the receptor epithelium was accompanied by a negative wave of potential, an increase in input resistance, and inhibition of spike activity. With worsening of the animal's condition the transepithelial potential became positive (up to +10 mV) but the input resistance of the ampulla during stimulation with a positive current was nonlinear in some cases: a regenerative spike of positive polarity appeared in the channel. During heating, the spike response was sometimes reversed in sign. It is suggested that fluctuations of the transepithelial potential and spike responses to temperature stimulation reflect changes in the potential difference on the basal membrane of the receptor cells, which is described by a relationship of the Nernst's or Goldman's equation type.I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. I. M. Sechenov, Institute of Evolutionary Physiology and Biochemistry, Academy of Sciences of the USSR, Leningrad. Pacific Institute of Oceanology, Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Translated from Neirofiziologiya, Vol. 12, No. 1, pp. 67–74, January–February, 1980.     

Principles of organization and evolution of systems of regulation of functions

Evolution of living organisms is closely connected with evolution of structure of the system of regulations and its mechanisms. The functional ground of regulations is chemical signalization. As early as in unicellular organisms there is a set of signal mechanisms providing their life activity and orientation in space and time. Subsequent evolution of ways of chemical signalization followed the way of development of delivery pathways of chemical signal and development of mechanisms of its regulation. The mechanism of chemical regulation of the signal interaction is discussed by the example of the specialized system of transduction of signal from neuron to neuron, of effect of hormone on the epithelial cell and modulation of this effect. These mechanisms are considered as the most important ways of the fine and precise adaptation of chemical signalization underlying functioning of physiological systems and organs of the living organism