鳗草根际溶磷微生物分离、筛选及其对鳗草生长的影响

为明确鳗草(Zosteramarina)根际溶磷微生物溶磷能力及其对鳗草生长的影响,采用选择性无磷培养基从鳗草根际土壤中分离获得4株具较高溶磷能力的菌株(P1、P2、P3和P4),从形态学、生理生化特征及16Sr DNA等方面对菌株进行了鉴定,探讨了菌株的最适培养条件,研究了其对鳗草植株存活、生长、生理及根际土壤酶活力的影响。结果表明,菌株P1～P4分别为芽孢杆菌(Bacillus altitudinis P1)、桑肠杆菌(Enterobacter mori P2)、大肠埃希氏菌(Escherichia coli P3)和Cobetia marina P4; 72 h菌株培养液中可溶性磷含量分别为116.98 mg/L、123.13 mg/L、130.21 mg/L和76.54 mg/L;最适培养温度分别为34.67℃、33.95℃、34.60℃和31.19℃;最适培养盐度分别为27.10、28.29、29.54和26.08;最适初始pH分别为8.26、7.92、8.17和8.21。鳗草室外盆栽实验证实,4个接菌处理组对鳗草植株的存活、生长生理及根际土壤酶活力等指标均有不同程度的提高或改善。其中菌株P2对鳗草生长的影响最为显著,单株新叶面积、地上及地下生产力最高,为(54.31±4.79)cm~2、(3.58±0.36)mg/(shoot·d)及(0.28±0.04) mg/(shoot·d),是对照组的2.77、2.91和1.75倍;叶片中叶绿素a、叶绿素b、总叶绿素和类胡萝卜素4种光合色素含量分别为31.35μg/cm~2、12.57μg/cm2、39.42μg/cm~2和6.21μg/cm~2,显著高于对照组(P0.05)。除菌株P4处理组外,其余各处理组的碱性磷酸酶活力均显著高于对照组(P0.05)。但脲酶含量与对照组无显著差异(P0.05)。综合分析认为,桑肠杆菌(Enterobacter mori P2)具备进一步研制溶磷微生物肥料的潜力,在海草床生态系统恢复中可能具有较高的应用价值。研究结果为深入探究高效溶磷菌株功能与代谢调控及其在鳗草植株人工促繁中的作用奠定了基础。     

一株高产琼胶酶菌株MA-B22的分子鉴定与产酶条件优化

琼胶酶在多糖降解应用中的作用日益重要，而从海洋微生物中筛选琼胶酶高产菌株成为一个重要途径。本研究从养殖的杂色鲍体内分离到一株高产琼胶酶的菌株MA-B22。该菌为革兰氏阴性菌，经16S rRNA序列鉴定表明，与Tamlana agarivorans sp. nov.具有99%同源性，因此初步定为Tamlana sp.。在2216E培养基中该菌株在培养时间60 h，温度25 ℃，起始pH为6.0条件下产酶活性最高。基于上述培养条件，通过单因素和正交实验确定了培养基的最佳基本组成：氮源为牛肉膏（其最适浓度为6.0 ‰），碳源为琼脂（其最适浓度为2.5 ‰），配制培养基的人工海水的最适盐度为25。经培养条件优化后，该菌胞外琼胶酶活力可达1021.79 U/mL，较优化前提高8.82倍。实验首次对Tamlana sp.属的琼胶酶活性进行确定并优化其产酶条件，为构建琼胶酶高产工程菌株提供了基础,并可能为今后鲍养殖提供潜在的益生菌。     

一株海洋红酵母的鉴定及其培养基的优化

通过菌落形态、培养特征和生理生化特征的测定,初步确定海洋红酵母HN-3为红酵母属的胶红酵母。比较不同的碳源、氮源、酵母膏质量分数和海水盐度对该酵母生长的影响,优化其培养基。试验结果表明,最佳培养基为2%葡萄糖、1.5%蛋白胨、1%酵母膏,盐度30。在该培养条件下,酵母菌HN-3的产菌量达到4.80×107cfu/mL,比初始发酵条件下的产菌量(4.20×107cfu/mL)提高了14.3%。     

抗生素处理对坛紫菜叶状体生长和藻际微生物的影响

设计了氨苄青霉素、硫酸庆大霉素和卡那霉素3种抗生素的不同组合处理坛紫菜叶状体,旨在筛选出坛紫菜叶状体藻际微生物的最优去除方法;同时,探究紫菜叶状体生长与微生物群落变化之间的关系。结果显示,低浓度(10μg/mL)的硫酸庆大霉素或高浓度(800μg/mL)的卡那霉素处理,对坛紫菜叶状体生长均具一定的抑制作用,而不同浓度的氨苄青霉素处理均促进了叶状体生长。500μg/mL的氨苄青霉素、500μg/mL的硫酸庆大霉素与300μg/mL的卡那霉素3种抗生素混合处理叶状体24 h,不会抑制叶状体的生长;同时,对藻际微生物有较强的抑制性。不同的坛紫菜品系,不同的叶状体日龄和培养密度,以及在不同的海水盐度和不同浓度的营养盐中培养,抗生素处理组圆盘体的生长均比对照组快。通过比较抗生素处理组与对照组分离的菌株后发现,抗生素处理组有两株菌落形态和菌株形态与对照组显著不同的特有菌株。研究表明,在坛紫菜叶状体的生长过程中,某些对叶状体生长起阻碍作用的细菌如果大量繁殖,会抑制对叶状体生长有益的细菌繁殖,当用抗生素抑制了阻碍生长的细菌,就会使益生菌成为优势菌,促进叶状体的生长,益生菌对上述抗生素的处理不太敏感,但由于培养条件的改变,抗生素对阻碍生长的细菌的抑制作用会减弱,使得它们大量繁殖,从而抑制叶状体的生长。     

一株凡纳滨对虾病原菌的分离、鉴定及其致病力分析

从患病凡纳滨对虾肝胰腺中分离出菌株20100612001,经人工感染实验证实,该分离菌株对凡纳滨对虾的半数致死量为1.44×106CFU/ml。形态学观察和革兰氏染色表明,该菌株为革兰氏阴性,无芽孢,有一根端极鞭毛;呈球杆状、球状、棒状或梨状且有两极浓染现象;在2216E培养基上为透明或半透明的圆形菌落,而在TCBS选择性培养基上为绿色或蓝绿色菌落。经Biolog碳源利用反应、脂肪酸气相色谱分析得出,该菌株与副溶血弧菌、需钠弧菌等的生理生化特性最相似;16SrD-NA序列测定表明,该菌株与弧菌属中几株病原菌的同源性均达到98.9%以上。在分子进化树中该菌株与副溶血弧菌Vibrio parahaemolyticus的进化地位最接近。综合上述实验结果分析得出,该细菌分离物为副溶血弧菌。     

海带表面降油细菌的分离鉴定及降油性能研究

用柴油为唯一碳源的培养基选择分离海带表面具有降解柴油性能的细菌;对分离菌株进行了形态学、生理生化特性以及16SrDNA序列分析并测定其生长特性;测定了接菌不同浓度(7×107 cfu/mL、7×108cfu/mL、7×109 cfu/mL)分离菌对柴油的降解率;另外,测定了加入不同浓度葡萄糖(0.5g/L、1g/L、2g/L、4g/L、6g/L、8g/L、10g/L)作用7d后分离菌对柴油的降解率。结果显示:从海带表面分离到2株降油细菌,编号为:HD-4和HD-6。HD-4菌株菌落形态圆形、直径1.5mm、黄色、不透明、边缘整齐,HD-6菌株菌落圆形,直径1.0mm,浅黄色、透明、边缘整齐。两株菌均为革兰氏阴性短杆菌。生理生化特征和16SrDNA序列分析确定HD-4菌株为假交替单胞菌(Pseudoalteromonas sp.),其16SrDNA同源性为99%;HD-6菌株为交替单胞菌(Alteromonas_sp.),其16SrDNA同源性为98%。2株菌最适生长温度均为15℃。HD-4和HD-6最适生长pH分别为9和8。适宜NaCl浓度分别为2%和4%;在25℃振荡培养(150r/min)7d,接菌量为7×107 cfu/mL、7×108 cfu/mL、7×109 cfu/mL时,HD-4对柴油的初始降解率分别为8.0%,22.1%和27.6%;HD-6初始降解率分别为23.7%、38.8%和43.2%。加入葡萄糖后2株菌的降油率均有所增高,加入4g/L葡萄糖时达最高值,3个接种浓度下HD-4菌株分别为85.4%、82.3%和80.4%,HD-6菌株分别为86.8%、93.7%和89.3%。当接菌量为7×107 cfu/mL,HD-4在葡萄糖含量为4g/L时作用7d,降油率可达到最大值86.72%,HD-6菌株在葡萄糖浓度6g/L达到最大值67.64%。葡萄糖浓度超过4g/L和6g/L时HD-4和HD-6菌株的降油性能有所下降。     

817肉鸡肠道乳酸菌及生理特性研究

为筛选817肉鸡同源性乳酸菌菌株,从健康30日龄肉鸡盲肠内容物中分离出LB1、LB2、LB3和LB4四种疑似乳酸菌,经革兰氏染色镜检,生化分析及糖发酵试验进行鉴定,并通过耐酸性、耐胆盐性及抑菌性生理特性研究。结果表明:4种菌株均初步判定为乳酸菌属,LB3和LB4在0.3%胆盐浓度的菌落存活数显著高于其他菌株(p<0.05);LB4和LB1在pH4.0酸度的存活菌数显著高于其他菌株(p<0.05);LB4抑菌圈直径最大,抑菌效果最佳。经综合评定,LB4菌株生理特性最佳,可作为乳酸菌制剂菌种备选。     

乌鳢的常见疾病

乌鳢 (Ｃｈａｎｎａａｒｇｕｓｃａｎｔｏｒ)经济价值较高 ,其养殖规模正日益扩大。本文通过文献和笔者自己的研究 ,阐述已知的乌鳢多发病的病因、病原、症状和防治方法。1　乌鳢败血病雷爱莹等认为该病为嗜水气单胞菌和豚鼠气单胞菌感染所致。前者在普通营养琼脂培养基上2 4ｈ形成边缘整齐 ,表面湿润 ,质地粘稠 ,微凸 ,半透明的圆形菌落 ,其菌体为革兰氏阴性、能运动的短杆菌。豚鼠气单胞菌在普通营养琼脂培养基上 2 4ｈ形成圆形、湿润、表面光滑、边缘整齐、微凸、乳白色的菌落 ,亦为革兰氏阴性能运动的短杆菌。两菌株与氧化酶、过氧化酶…     

益生菌D-1液体发酵工艺的研究

为提高菌体的得率和芽孢转化率,进行了菌株D1最佳培养条件参数和培养基优化的研究及测定此条件下的生长曲线。通过研究发酵温度、接种量、培养基初始pH、溶解氧等因素对菌株D1生长的影响,确定最佳培养条件为:培养温度30℃,培养基初始pH7.0,接种量5%(相对摇瓶装液量),装液量100mL/500mL。在发酵基础培养基成分保持不变的情况下改变氮源、碳源、生长因子、无机盐单因子进行单因子试验,采用L9(3)4正交表设计实验,进行培养基优化,确定最佳培养基配比为玉米淀粉2%,蛋白胨2.5%,NaH2PO40.8%,玉米浆1.5%,MgSO4·7H2O0.05%,3.08%MnSO4水溶液0.1%。在最佳培养条件下,用最优培养基测定了菌株D1的生长曲线,并确定了菌株D1的最佳种龄为18～20h,生产收获时间为26h。     

一株芽孢杆菌PC024的鉴定及其抗WSSV感染效果的研究

为了筛选WSSV的防病益生菌株,从健康中国明对虾消化道分离纯化一株芽孢杆菌PC024,经Biolog碳源利用反应、ATB微生物自动鉴定系统、脂肪酸气相色谱分析得出该菌株与坚强芽孢杆菌的生理生化特性最为相似,该菌株为革兰氏阳性菌,有一根端极鞭毛;细胞呈球杆状,有椭圆芽孢;单个菌落呈圆形,中间略微凸起;16S rRNA序列分析表明,该菌株与坚强芽孢杆菌进化地位最接近,同源性均达到100％,综合以上4种方法的鉴定结果,该菌株被鉴定为坚强芽孢杆菌.将已鉴定的PC024菌株粘附于对虾饲料表面投喂给凡纳滨对虾20 d后,进行WSSV肌肉注射感染,测定投喂和感染后对虾血淋巴上清和肝胰腺的免疫相关酶活性,并对对虾肠道总菌数和添加菌PC024进行计数及鉴定.结果表明:添加该菌的实验组对虾相对存活率高,相对保护率达33.7％;投喂含该菌饲料的实验组对虾血清和肝胰腺的相关免疫酶活性较对照组显著提高,对虾肠道总细菌数始终显著高于对照组,并在实验组能够分离得到坚强芽孢杆菌,坚强芽孢杆菌PC024可作为WSSV的防病益生菌株应用于对虾养殖生产.     

根瘤菌N_1对扁藻生长影响的研究

研究了由海藻培养体系中分离获得的10株细菌对扁藻生长影响。试验结果表明,菌株N1对自然带菌扁藻及除菌扁藻的生长均有明显的促进作用;经16SrDNA分析表明,菌株N1为根瘤菌属细菌。     

Distribution of three algicidal <Emphasis Type="Italic">Alteromonas</Emphasis> sp. strains in seagrass beds and surrounding areas in the Seto Inland Sea,Japan

Harmful algal blooms (HABs) often cause great damage to the fish aquaculture industry in the western part of Japan. Bacteria that effectively kill such phytoplankton are found in coastal seawater and are considered to influence the occurrence of HABs. Algicidal bacteria are found in abundance in seagrass beds; however, the distribution of particular bacterial strains has not yet been clarified. In this study, we determined the abundance of three algicidal Alteromonas sp. strains that were isolated as Chattonella antiqua-killing bacteria in seagrass beds and their surrounding areas in summers of 2013–2015. The strains were detected using a quantitative polymerase chain reaction (qPCR) amplification method. Two of the three algicidal bacterial strains were remarkably abundant in the seawater of an enclosed seagrass bed compared to the surrounding areas. In addition, the abundance of the three algicidal bacteria decreased when the eelgrass withered in late summer. These results suggest that growth of these algicidal bacteria was stimulated by eelgrass. The bacterial abundance estimated by qPCR was much greater than that determined by the culture-dependent method in June 2015 when the eelgrass grew thickly. This implies that the qPCR assay could be a sensitive tool to evaluate algicidal bacteria in natural environments.     

碳氮营养和培养条件对芽孢杆菌(Bacillus sp.) A4生长的影响

芽孢杆菌(Bacillus sp.) A4是一株具有溶甲藻能力的菌株，为探究营养条件与培养条件对A4生长的影响，明确在多因素共同作用下菌株的生长特性，先以单因素方法比较不同碳、氮营养因子对其生长的影响，再以Plackett-Burman方法综合比较碳源、氮源、pH、接种菌量、温度、转速、装液量等因子对其生长的协同影响效应。结果显示，A4菌对有机碳源玉米浆和有机氮源大豆蛋白利用效果最好，培养24 h后菌量分别达到3.58×108、3.19×108 CFU/ml。各因子的重要性排序依次为大豆蛋白、温度、玉米浆、转速、接种菌量、pH、装液量，且大豆蛋白和温度对A4菌的生长影响显著(P<0.05)。研究表明，培养条件对菌株生长调控也有重要意义，在评估相关因素对菌株生长或生态功能的影响时，须将营养条件和培养条件协同分析。     

蛭弧茵裂解作用的初步研究

蛭弧菌是一种寄生性细菌,广泛分布干土壤及备种水域之中,对诸多革兰氏阴性菌尤其是水产动物病原菌具有吞噬裂解活性.本文选取七株细菌为宿主菌,对蛭弧菌的裂解作用进行了初步研究.结果表明:除金黄色葡萄球菌外.蛭弧菌对其他六株菌均具有不同程度的裂解活性,其中以对红色假单胞菌的裂解能力更强.     

蛭弧菌裂解作用的初步研究

蛭弧菌是一种寄生性细菌．广泛分布干土壤及各种水域之中．对诸多革兰氏阴性菌尤其是水产动物病厚菌具有吞噬裂解活性。本文选取七株细菌为宿主菌．对蛭弧菌的裂解作用进行了初步研究。结果表明：除金黄色葡萄球菌外，蛭弧菌对其他六株菌均具有不同程度的裂解活性．其中以对红色假单胞菌的裂解能力更强。     

The seagrass Zostera marina harbors growth-inhibiting bacteria against the toxic dinoflagellate Alexandrium tamarense

Seagrasses are known to have allelopathic activity to reduce growth of phytoplankton. We found growth-inhibiting bacteria (strains E8 and E9) from Zostera marina possessing strong activity against the toxic dinoflagellate Alexandrium tamarense. Strain E9 markedly inhibited growth of A. tamarense even with initial inoculum size as small as 2.9 cells ml^?1. This bacterium also had growth-inhibiting effects on the red-tide raphidophytes Chattonella antiqua and Heterosigma akashiwo, the dinoflagellate Heterocapsa circularisquama, and the diatom Chaetoceros mitra. Small subunit (SSU) ribosomal DNA (rDNA) sequencing analysis demonstrated that the most probable affiliation of these strains was Flavobacteriaceae, and proved that another inhibitory bacterial strain (E8) was the same species as strain E9. Two other bacterial strains (E4-2 and E10), showing different colony color and isolated from the same seagrass sample, revealed no growth-inhibiting activity. Interestingly, strain E4-2 showed the same sequences as E8 and E9 (100 %), and strain E10 matched E8 and E9 with 99.80 % similarity. Growth-inhibiting bacteria against the toxic dinoflagellate Alexandrium tamarense associated with seagrass, such as Flavobacterium spp. E8 and E9, are able to repress shellfish poisoning besides the allelopathic activity of seagrass itself.     

Effects of beneficial bacteria on biomass,photosynthetic parameters and cell composition of the microalga Muriellopsis sp. adapted to grow in seawater

The present study evaluated the effects of five bacterial isolates from the microalga Muriellopsis sp. on the microalgal biomass concentration (g/L), specific growth rate (K), photosynthetic quantum yield (QY), non‐photochemical quenching (NPQ), maximum relative electron transport rates (rETR max) and levels of nutritional components such as carbohydrates, lipids, proteins and carotenoids in Muriellopsis sp. cultivated in seawater under indoor and outdoor conditions. The bacterial strains were Microbacterium sp. Dom 1; Pseudomonas sp. Dom2; Microbacterium sp. Dom 3; Rhizobium sp. Dom 4; and Dietzia sp. Dom 5, as well as the Pseudoalteromonas sp. (SLP1), a bacterium known to promote the growth of microalgae. At the laboratory level, inoculation of the strains SLP1, Dom 1, Dom 3 and Dom 5 resulted in higher specific growth rates and biomass of the microalga. Subsequently, the best results were obtained with a combination of the selected bacterial strains (Dom1, Dom 3, Dom5 and SLP1) under outdoor culture conditions improved the biomass, proteins, carbohydrates and total carotenoids in 22.12%, 48.28%, 19,25% and 48.27%, respectively, compared to cultures without the incorporation of the selected bacteria (control), while no effects were observed on the photosynthetic parameters. Thus, it was demonstrated that positive associations of the selected bacterial strains played an important role in the production of Muriellopsis sp. acclimatized to grow in seawater. This is of crucial importance, especially in desert areas, where solar radiation is high and freshwater is a limited resource.     

海草有性繁殖成花诱因研究进展与展望

海草是一类生活在热带至温带浅海、完全适应海洋环境的沉水被子植物的总称。海草床作为连接珊瑚礁与红树林的纽带，具有重要的生态功能与经济价值。近年来，随着人们对海草认识的不断加深，海草的有性繁殖行为逐渐受到关注，而成花诱导是海草从营养生长向生殖生长过渡的重要环节。本文综述了海草有性繁殖中成花诱因的研究进展，探讨了温度、光照、盐度等相关因子对海草成花诱导的影响，分析了海草响应外界环境刺激与内源信号启动开花途径可能集中在光周期途径、春化途径和自发途径上。建议未来海草床保护修复工作应加强对海草有性生殖行为的研究，明确不同海域海草的集中开花和结果时间，对海草床生态系统的修复与保护具有重要意义。     

Implications of nutrient enrichment for the conservation and management of seagrass Zostera muelleri meadows

1. Nutrient overenrichment in aquatic environments, or eutrophication, is increasingly affecting seagrass habitats around the world, leading to the degradation of seagrass ecosystems and the loss of associated ecosystem services.
2. The resistance of seagrass to nutrient enrichment is believed to be site specific, yet the direct correlations between environmental factors and the resistance of seagrass meadows has not yet been adequately resolved. The response of seagrass beds to long‐term multiple‐level sediment nutrient enrichment represents a current research gap.
3. This study therefore assessed the in situ long‐term influence of four levels of sediment urea fertilizer addition on Zostera muelleri plants using a manipulative experimental design at three sites with diverse sediment characteristics. Specifically, this study investigated the response of porewater nutrient concentration, seagrass morphology indices, and seagrass plant tissue carbon and nitrogen contents under experimental nutrient stress levels.
4. Over a 13‐month experiment, sediment nutrient addition substantially increased the ammonium concentrations in the sediment porewater, significantly decreased seagrass morphology indices, and caused a carbon and nitrogen imbalance in plant tissues. Ammonium toxicity was more pronounced in seagrass meadows growing on sandy substrates with lower relative above‐ground biomass, which showed low resistance to eutrophication at sediment ammonium concentrations of up to 1 × 10⁴ μM. Plants growing in muddy sand substrates with higher relative above‐ground biomass were more resistant to nutrient impacts, however, with a delayed negative response observed in response to higher nutrient concentrations (up to 1 × 10⁵ μM).
5. Our findings suggest that seagrasses in low‐nutrient sandy environments show more rapid responses to eutrophication, although seagrasses in both sandy and muddy substrates exhibited declines in response to a long‐term elevation of sediment nutrient concentrations. While continuing to assess the relative susceptibility of seagrass habitats across differing environments to inform coastal management, conservation efforts should allocate resources accordingly and prioritize reducing nutrient overenrichment in sensitive seagrass meadows.

     

蛭弧菌海水菌株Bdh5221裂解特性及生长影响因子研究

对利用双层琼脂平板法分离纯化获得的蛭弧菌海水菌株Bdh5221裂解特性及生长影响因子进行了初步研究,为其在生物防治上应用提供理论依据。研究结果表明,蛭弧菌海水菌株Bdh5221对嗜水气单胞菌、副溶血弧菌、鳗弧菌、溶藻弧菌、哈维氏弧菌、大肠杆菌、荧光假单胞菌、迟钝爱德华氏菌等革兰氏阴性菌有较好的裂解作用;对八叠球菌、金黄色葡萄球菌、枯草芽胞杆菌等革兰氏阳性菌的裂解能力较弱;对木糖葡萄球菌和啤酒酵母菌不裂解;可在超声波破碎后的G+菌和酵母菌上生长。蛭弧菌Bdh5221在宿主菌浓度106~109cfu/ml下均可正常生长,高浓度宿主菌更有利于蛭弧菌生长;Bdh5221最适生长的pH在7.0~7.5之间,盐度为20~30左右;Bdh5221增殖速度与起始接种浓度影响不大,起始接种浓度101~103pfu/ml下经过5~7d生长可增殖104左右。