卵形鲳鲹结节病病原的分离与鉴定

从湛江港、阳江闸坡海水网箱养殖的患结节病卵形鲳鲹(Trachinotus ovatus)中分离一株细菌,回归感染结果证明该菌是引起卵形鲳鲹结节病的病原,对卵形鲳鲹半致死浓度为45 g-1。该菌株呈革兰阳性,好氧,具有弱抗酸性,菌体呈短杆状或细长分枝状,过氧化氢酶阳性,氧化酶阴性,还原硝酸盐,不水解酪素、黄嘌呤、酪氨酸、淀粉、明胶,以柠檬酸盐为唯一碳源生长。对其16S rDNA序列作Blast分析,构建系统进化树。结果表明,该菌株与诺卡氏菌属的菌株亲缘关系最近,且与鰤鱼诺卡氏菌(Nocardia seriolea JCM 3360T)的16S rDNA序列同源性高达99%。综合患病鱼的症状及病原菌形态、生理生化特性及16S rDNA序列的结果,该菌被鉴定为鰤鱼诺卡氏菌(N.seriolea)。     

一株产植酸酶菌株的分离鉴定及其产酶特性

<正>植酸酶(phytase)是催化植酸和植酸盐水解成肌醇和磷酸(或盐)的一类酶的总称,是一类特殊的酸性磷酸酶。饲料中添加植酸酶可改良磷酸盐的生物利用度,减少无机磷的添加,缓解我国磷资源缺乏、磷供应不足的局面;消除植酸的抗营养作用,     

Molecular identification and culture trials of Eutreptiella gymnastica (Eutreptiales, Euglenophyceae)

During a survey for marine microalgal resources, we isolated a rare marine euglenoid from the coastal waters of Qingdao, China in 2009, and established a pure culture. Electron microscopic and molecular phylogenetic (18S rDNA and 16S rDNA sequences) analyses revealed a close affinity with Eutreptiella gymnastica, a bloom-forming species. Different culture conditions were monitored to understand optimal E. gymnastica growth characteristics. The optimal growth conditions in a batch culture of this isolate were 20°C, 160 μmol photons/(m2×s) of white light, and a salinity of 10-31. Nutrient experiments demonstrated that growth increased dramatically with a phosphorus concentration greater than 72 μmol/L. Understanding the effect of culture conditions on E. gymnastica may help understanding the blooming mechanism of this alga in its natural environment.     

Phylogenetic analysis of bacteria in sea ice brine sampled from the Canada Basin, Arctic Ocean

Bacterial diversity in sea ice brine samples which collected from four stations located at the Canada Basin, Arctic Ocean was analyzed by PCR-DGGE. Twenty-three 16S rDNA sequences of bacteria obtained from DGGE bands were cloned and sequenced. Phylogenetic analysis clustered these sequences within γ-proteobacteria, Cytophaga-Flexlbacter-Bacteroides （CFB） group, Firmicutes and Actinobacteria. The phylotype of Pseudoalteromonas in the γ-proteobacteria was predominant and members of the CFB group and γ-proteobacteria were highly abundant in studied sea ice brine samples.     

环境16S rDNA和16S rcDNA序列分析湖光岩玛珥湖的浮游细菌组成

通过提取环境总16S rDNA和总16S rRNA分别构建DNA克隆文库和反转录cDNA文库,并进行克隆测序和序列分析,探讨湖光岩玛珥湖浮游细菌和浮游活性细菌的遗传多样性。结果表明:构建两个水层的4个克隆文库,即1 m和10 m水层总菌的16S rDNA文库和总活性菌的16S rcDNA文库,共获得413条序列,分属15门、32目、52科;1 m水层的rDNA文库与rcDNA文库中Verrucomicrobia类群所占比例最大(36.8%和32.1%),其次为Alphaproteobacteri(a 15.1%和16%)和Betaproteobacteri(a 17.9%和16%);在10 m水层的2个文库中,Alphaproteobacteria类群均占绝对优势,分别为63.5%(rDNA)和43.8%(rcDNA),其次为Verrucomicrobia(11.5%和14.3%),其他细菌类群包括Acidobacteria、Chloroflexi、Firmicutes、待定门OD1、Planctomycetes、Spirochetes和Deltaproteobacteria,比例在0.8%~3.8%之间;在科的水平上,SAR11为湖光岩玛珥湖最为丰富的类群,占总克隆数的26.9%,其中在10 m水层的比例高达51.5%。序列同源性分析表明,绝大多数序列(89.8%)来源于新种,其中19.6%的序列可能来自于新属,69%的序列可能来自于全新的科。湖光岩玛珥湖浮游细菌群落结构较为独特,有大量的浮游细菌种类尚未获得相应的纯培养物,蕴含着丰富而新颖的微生物资源。     

The phylogeny of native and exotic scallops cultured in China based on 16S rDNA sequences

Scallops of the Family Pectinidae are a valuable resource in marine industry of the world. Understanding the phylogeny of the family is important for the development of the industry. In this study, partial 16S mitochondrial rDNA genes were obtained from 8 scallop species that are commonly cultured indigenous and transplanted species in China. Phylogenetic relationships of Pectinidae were analyzed based on the 8 sequences and other 5 published ones in GenBank, representing 9 genera of the family. The molecular phylogeny trees were constructed using 3 methods with software PHYLIP. The results showe that total 13 species of scallops clustered in 4 clades. Pecten maximus joins P. jacobaeus then Amusium pleuronectes in cluster, indicating close relationship of genus Amusium with Pecten in evolution. P. yessoensis is close to Chlamysfarreri and C. islandica. No enough material was available to single out genus Patinopecten as an independent monophyletic subfamily. The position ofAdamussium colbecki indicates that it is far from genus Pecten but near to genus Chlamys in evolution.     

分离自桉树枯叶拮抗菌株的鉴定及拮抗性试验

从桉树枯叶中分离到的4株微生物菌株,对好食脉孢霉(Neurospora sitophila)具有拮抗作用。其中ED013、ED018和ED015抑菌圈之间差异不显著,与对照无菌水和多菌灵有极显著性的差异。ED014抑菌圈比前3个菌株效果差,但也与照无菌水和多菌灵有极显著性的差异。根据形态特点及生理生化测定结果鉴定4株菌株属于芽孢杆菌(Bacillusspp.)。     

Isolation and identification of bacteria associated with the surfaces of several algal species

We conducted this study to assess the diversity of bacteria associated with the surfaces of algae based on 16S rDNA sequence analyses.Twelve strains of bacteria were obtained from the surfaces of the following four species of algae:Gracilaria textorii,Ulva pertusa,Laminaria japonica,and Polysiphonia urceolata.The isolated strains of bacteria can be divided into two groups:Halomonas and Vibrio,in physiology,biochemical characteristics and 16S rDNA sequence analyses.The phylogenetic tree constructed based on ...     

Screening and molecular classification of low-temperature protease from Antarctic microorganism and its characterization

107 strains producing protease were screened from 260 strains of Antarctic psychrophilic bacteria, among which proteolytic activity of five strains was more than 45 U ml^-1. The 16S rRNA gcne sequences homology and phylogcnetic analysis of five Antarctic psychrophillc bacteria showed that NJ276, NJS-9, NJ16-70,NJ345 belonged tO the described genus Pseudoalteromonas and NJ341 belonged to the genus Colwellia. The growth and the protease characteristic of four Antarctic psychrophilic bacteria had been studied, and the result showed that the 6ptimal temperature for growth and protease-produeing of four strains was about 10℃. Their growth and protease-produeing were still high during incubatlng 2-5 days. The maximum proteolytic activity occurred at pH 9 for four Antarctic psychrophilic bacteria. The optimal temperature of protease action of both strains NJ276 and NJ5-9 was about 50℃, however, the optimal temperature of protease aetlon of both strains NJ341 and NJ345 was about 40 ℃, and their proteolytic activity under 0℃ exhibited nearly 30% of the maximum activity, but their thermal stabilities were weaker. These results indicated that proteases from NJ341 and NJ345 were low-temperature proteases.     

海洋短小芽孢杆菌ZH1-6菌株的鉴定及生物学特性

从新鲜近江牡蛎中分离到一株拮抗细菌,命名为ZH1-6,该菌对金黄色葡萄球菌、乙型副伤寒沙门氏菌及大肠杆菌等多种病原菌有较强的抑制作用。通过形态学观察、常规生理生化指标测定、16SrDNA序列测定和同源性分析,鉴定该菌株为短小芽孢杆菌。研究表明:ZH1-6能利用多种碳、氮源,其生长温度范围为10-50℃,生长pH范围为pH3-10,最适初始pH为6.0。     

马氏珠母贝肠道及其养殖水体可培养细菌群落结构

【目的】了解马氏珠母贝(Pinctada fucata martensii)肠道及其养殖水体可培养细菌的群落组成。【方法】采用2216E平板涂布法研究海区养殖马氏珠母贝肠道与养殖水体的可培养菌群种类及丰度。【结果与结论】马氏珠母贝肠道及其养殖水体的可培养细菌归属于2门(变形菌门和厚壁菌门)3纲7目10科23属56种。属水平上,肠道中以弧菌属(74.7%)和假交替单胞菌属(18.7%)为主;养殖水体中α-变形菌纲的FJ943236_g属(40.7%)丰度最大,弧菌属(16.7%)相对肠道丰度较低。样品共有菌属为弧菌属、假交替单胞菌属、发光杆菌属和芽孢杆菌属;肠道特有菌属为希瓦氏菌属和盐单胞菌属;养殖水体特有菌属主要为FJ943236_g、鲁杰氏菌属和Nautella。在种水平上,7个种为二者共有;马氏珠母贝肠道和养殖水体特异性菌种分别为18个和31个。虽然门水平上马氏珠母贝肠道中可培养细菌群落与其养殖水体中的细菌群落大致相似,但在属、种水平上二者差异明显。     

海洋弧菌鉴定与分类相关功能基因研究进展

【目的】探究功能基因在海洋弧菌物种鉴定中的作用,为海洋弧菌多样性研究以及致病性弧菌的监测和防控提供参考。【方法】根据已有的弧菌分类学研究成果,阐述16S rRNA基因、管家基因和毒力基因等相关功能基因在海洋弧菌鉴定与分类研究中的应用进展。【结果】16S rRNA基因和功能基因可用于海洋弧菌的分类学及其快速检测鉴定的研究,对致病性弧菌的诊治具有重要的意义。【结论】功能基因和16S rRNA基因在海洋弧菌菌种鉴定中的广泛应用,提高了海洋弧菌种间分类的准确性,对海洋弧菌的多样性研究以及水产养殖和人类健康的风险评估有重要价值。探索新型功能基因在海洋弧菌分类学研究和快速鉴定中的应用有现实意义。     

16S rRNA Gene Phylogenesis of Culturable Predominant Bacteria from Diseased Apostichopus japonicus(Holothuroidea,Echinodermata)

Cultured Apostichopusjaponicus in China suffers from a kind of skin ulceration disease that has caused severe economic loss in recent years. The disease, pathogens of which are supposed to be bacteria by most researchers, is highly infectious and can often cause all individuals in the same culture pool to die in a very short time. The 16S rRNA gene phylogenesis of the culturable bacteria from the lesions of diseased individuals was conducted to study the biodiversity of the bacterial communities in the lesions and to identify probable pathogen(s) associated with this kind of disease. S. japonica samples were selected from a hatchery located in the eastern part of Qingdao, China. Bacterial universal primers GM5F and DS907R were used to amplify the 16S rRNA gene of bacteria colonies, and touchdown PCR was performed to amplify the target sequences. The results suggest that γ- proteobacteria (Alteromonadales and Vibrionales) of CFB group, many strains of which have been also determined as pathogens in other marine species, are the predominant bacterial genera of the diseased Apostichopusjaponicus individuals.     

一株海水氨氧化细菌的系统发育分析

应用PCR技术扩增16S rRNA基因和amoA(ammonia monooxygenase subunit A)的基因片段,并测定其序列,对一株源于海水养殖水体的高效氨氧化细菌(ammonia-oxidizing bacteria,AOB)进行了系统发育分析。结果表明,经PCR扩增得到了1 098 bp的16S rRNA基因片段和491 bp的amoA基因片段,将其序列用NCBI-Blast软件在GenBank数据库中进行同源性检索后发现,该菌株的16S rRNA基因序列和amoA基因序列分别与亚硝化单胞菌Nitrosomonas sp.NS20的相对应基因片段相似性分别为98.4%和96.7%。在此基础上构建了系统发育树,表明用该菌株的16S rRNA基因片段和amoA基因片段构建的系统发育树均与亚硝化单胞菌属类聚在一起,结合该菌株形态和生理生化特性,鉴定该株氨氧化细菌属亚硝化单胞菌。     

Isolation and characterization of a fucoidan-degrading bacterium from Laminaria japonica

Fucoidan, a polysaccharide containing abundant fucose and sulfate ester group, was prepared from Laminaria japonica. In order to obtain fucoidan-degrading enzyme, bacteria capable of degrading fucoidan were screened from kelp. A bacterial strain named RC2-3 was obtained, which degraded fucoidan by the maximum extent of 54% ± 1.3%, the highest among all bacterial isolates. High-performance size exclusion chromatography(HPSEC) showed that the molecular weight of fucoidan was gradually reduced by RC2-3 with culturing time, suggesting the production of fucoidan-degrading enzyme by RC2-3. Phylogenetic analysis of partial 16S ribosomal RNA gene(16S rDNA) sequence showed that RC2-3 belonged to the family Flavobacteriaceae. However, it showed different physiological and biochemical characteristics from the known Flavobacteriaceae members producing fucoidan-degrading enzyme, thus RC2-3 was proposed to be a new member of this family.     

Screening and Characterization of Nitrite-Degrading Bacterial Isolates Using a Novel Culture Medium

In this study,a novel culture medium that simulates shrimp pond conditions was established to screen nitrite-degrading isolates.The medium was supplemented with nitrite as a nitrogen source and shrimp feed as the major carbon source,to achieve the high nitrogen and low carbon nutritional status found in shrimp farming ponds.Screening using this medium identified potent denitrifying Bacillus isolates,among which Bacillus subtilis M7-1 was considered best.M7-1 was able to completely degrade nitrite-N in 24 h without much consumption of dissolved oxygen.Efficient denitrification activity took place in liquid cultures within a set of non-stringent ranges of pH(5.0–9.0),salinity(0–30)and temperature(25–35℃).The denitrifying enzyme gene was amplified,sequenced and further identified as nirS type.In biosecurity assessments,M7-1 had no negative effects on shrimps at a dose of 106 cfu mL−1.M7-1 could therefore be used in aquaculture to reduce and control the nitrogen concentration,and to promote the development of sustainable and healthy culture systems.     

Molecular phylogeny of Parapenaeopsis Alcock, 1901 (Decapoda: Penaeidae) based on Chinese materials and 16S rDNA and COI sequence

The phylogenetic relationship among Chinese Parapenaeopsis species was studied by comparing 16S rDNA and COI gene sequence. The results showed that Parapenaeopsis hardwickii (Miers, 1878) and P. cultrirostris Alcock, 1906 identified from Chinese samples were the same species. Parapenaeopsis cornuta (Kishinouye, 1900), P. incisa Liu and Wang, 1987, and P. sinica Liu and Wang, 1987 were different species. However, their systematic relationship were closer than those of other species, and they formed an advanced branch in the phylogenetic trees. Additionally, the systematic position of P. hardwickii (Miers, 1878), P. hungerfordi Alcock, 1905, and P. tenella (Bate, 1888) were not stable in the phylogenetic trees. More genetic markers such as 18S rDNA and 28S rDNA were supposed to be used to confirm the phylogenic relationship of Parapenaeopsis species.     

Construction of Porphyra yezoensis Pure Line from Protoplasts and Its 18S rDNA Sequence Determination

1　Introduction　PorphyraisthemainobjectforalgafarmingandplaysaveryimportantroleinChinesemarineindus tries.Recently ,therehasbeenagreatlossinPor phyracultivationduetothedegenerationoftheculti var,sothereisanincreasingdemandforgoodPor phyracultivars .Theprerequisiteofthetraditionalbreed ingandbioengineeringresearchofPorphyraistheconstructionofpurelines .Traditionally ,theclassifi cationofPorphyrawasaccordingtotheirmorphologi calcharacteristics .However ,mostmorphologicalfea turesofPorphyraar…     

16S rRNA gene phylogenesis of culturable predominant bacteria from diseased Apostichopus japonicus (Holothuroidea, Echinodermata)

Cultured Apostichopus japonicus in China suffers from a kind of skin ulceration disease that has caused severe economic loss in recent years. The disease, pathogens of which are supposed to be bacteria by most researchers, is highly infectious and can often cause all individuals in the same culture pool to die in a very short time. The 16S rRNA gene phylogenesis of the culturable bacteria from the lesions of diseased individuals was conducted to study the biodiversity of the bacterial communities in the lesions and to identify probable pathogen(s) associated with this kind of disease. S. japonica samples were selected from a hatchery located in the eastern part of Qingdao, China. Bacterial universal primers GM5F and DS907R were used to amplify the 16S rRNA gene of bacteria colonies, and touchdown PCR was performed to amplify the target sequences. The results suggest that γ- proteobacteria (Alteromonadales and Vibrionales) of CFB group, many strains of which have been also determined as pathogens in other marine species, are the predominant bacterial genera of the diseased Apostichopus japonicus individuals.