Effect of dietary GroBiotic®‐A supplementation as a prebiotic on the intestinal microflora,growth performance,haemato‐serological parameters,survival rate and body composition in juvenile beluga (Huso huso Linnaeus, 1754)

The objectives of the present study were to investigate of GroBiotic^®‐A (GBA) on growth, autochthonous intestinal microbiota and haemato‐serological parameters of beluga juvenile. A total of 180 fish (40.82 ± 5.81 g) were fed diets containing graded levels of GBA (0, 5, 10 and 20 g kg^?1 diet) for 8 weeks. No significantly differences in body composition, total viable aerobic bacteria, mean cell volume, mean cell haemoglobin, mean cell haemoglobin concentration, neutrophils, eosinophils, monocytes, albumin, glucose, triglyceride, cholesterol, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and lactate dehydrogenase were detected between treatment groups. The fish fed on 10 and 20 g kg^?1 GBA significantly showed higher lactic acid bacteria, final weight, body weight increases, weight gain and lower feed conversion ratio compared with the control and 5 g kg^?1 groups. The group fed 20 g kg^?1 GBA showed a highly significant difference in condition factor, survival rate, final length, total red and white blood cells, lymphocytes, haematocrit, haemoglobin, total protein, total immunoglobulin and lysozyme activity. The specific growth rate of the treatment groups was significantly elevated compared with the control groups. These results indicated that GBA at level 20 g kg^?1 improved growth, welfare and survival of beluga juvenile.     

高寒地区燕麦根际联合固氮菌研究 Ι固氮菌分离及鉴定

结合气相色谱仪,利用乙炔还原等方法对高寒地区重要饲用植物——燕麦(Avenasativa)根际联合固氮菌进行了分离和鉴定。结果表明,该地区燕麦根际联合固氮菌株较少(8株),菌株分布以根系表面(RP)最多,根表土壤(RS)次之,距根系较远的土壤(NRS)和根内(HP)最少,即:RP>RS>NRS≥HP;菌株固氮酶活性相差较大(C2H4112.5～1147.9nmol/mL·h),具有较高固氮酶活性的菌株较少(C2H4大于500nmol/mL·h只有2株);菌株均为革兰氏阴性菌,经鉴定分属Azotobacter(3株)、Pseudomonas(3株)和Azospirillus(2株)3个属。相对于其它生境和植物,高寒地区燕麦根际联合固氮菌种类较为单一。     

Immunocytochemical localization of the Bacillus sphaericus binary toxin components in Culex quinquefasciatus (Diptera: Culicidae) larvae midgut

This study describes the immunocytochemical localization of the Bacillus sphaericus 2362 binary toxin components, BinA and BinB, in Culex quinquefasciatus larvae that had been intoxicated with this entomopathogen. Ultrathin sections of C. quinquefasciatus larvae midgut embedded in the hydrophilic resin L.R. White were incubated with the antibodies anti-BinA or anti-BinB and then revealed with goat anti-rabbit IgG coupled to gold particles. Immunocytochemical detection demonstrated the presence of specific labeling in ultra-thin sections that had been incubated with the BinA antiserum. Gold particles were detected on the apical areas of cell membranes and inside the epithelial cell cytoplasm, particularly the mitochondria, of cells from the gastric caeca and posterior stomach in larvae exposed during 2 or 24 h to the entomopathogen. A similar labeling pattern was observed in ultrathin sections from both midgut regions when incubated with BinB antiserum.     

光合细菌对苗期水稻抗氧化作用的影响

光合细菌施用于水稻,经紫外线照射后对水稻色素及抗氧化酶系统的影响进行了研究。结果表明,经紫外线照射后的水稻过氧化氢酶、超氧化物歧化酶、叶绿素含量发生变化,紫外线辐射对水稻的过氧化氢酶（CAT）、超氧化物歧化酶（SOD）活性及叶绿素含量均有诱导作用,而光合细菌对水稻接受紫外线照射具有保护作用。     

内生细菌Bacillus sp.对菠菜枯萎病的防治效果研究

[目的]探讨内生细菌Bacillussp.对菠菜枯萎病的防病作用。[方法]就内生菌Bacillussp.对菠菜枯萎病菌平板抑制作用、不同浓度内生菌对菠菜枯萎病的防治效果及内生菌在菠菜根部的定殖位点进行研究。[结果]结果表明,浓度为1×107cfu/ml时,Bacillus sp.对菠菜枯萎病防治效果最好,且内生菌定殖在菠菜根部木质部导管中。[结论]从菠菜根部筛选出的内生细菌Bacillussp.对菠菜枯萎病有的较好防治效果,可以利用此开发具有潜在生防价值的生物制剂。     

3株烟草内生细菌促进作物生长作用的研究

通过漂浮育苗试验以及大田试验,研究了烟草内生细菌YN201408、YN201442和YN201448的促生长作用。结果表明:3个菌株的菌悬液均可促进烟草、番茄、白菜、玉米和油菜的生长,其中YN201448对烟草和番茄的促生长效果最好,YN201408促进白菜生长的作用较大,而YN201442对玉米和油菜的促生长作用最好。     

茄科植物内生细菌的分离及拮抗菌的筛选

从番茄和辣椒植株中共分离到9株对植物病原真菌具有拈抗作用的内生细菌。其中，来自樱桃番茄的内生细菌株系BS-1和湘研辣椒的内生细菌株系BS-4对辣椒根腐病菌等具有较强的拈抗作用，两者在植株体内均可以定殖。BS-1和BS-4均属于芽孢杆菌。     

红树内生细菌菌株Kc-38的抗菌物质及对采后芒果炭疽病的防效

Kc-38菌株是本实验室从红树植物秋茄Kandelia candel体内分离得到的内生细菌,对峙生长法测定发现该菌株对芒果炭疽病菌Colletotrichum gloeosporioides和枯萎病菌Fusarium oxysporum等多种植物病原菌具有较强的抑制作用.根据菌体形态、培养特性、生理生化反应及16S rDNA序列分析将该菌株初步鉴定为解淀粉芽孢杆菌Bacillus amyloliquefaciens.该菌株对芒果炭疽病具有良好的防效,用菌株发酵液及发酵上清液处理9d后,对采后芒果炭疽病的防效分别达到65.12%和62.79%.进一步研究表明,其分泌的胞外抗菌物质为一类对热稳定和抗紫外照射的蛋白类物质,在pH2.0～11.0范围内均具有抑菌作用,以pH2.0～8.0范围内的抗菌活性较强.     

The effect of piscidin antimicrobial peptides on the formation of Gram-negative bacterial biofilms

Fish-derived antimicrobial peptides are an important part of the innate immune system due to their potent antimicrobial properties. Piscidins are a class of antimicrobial peptides first described in hybrid striped bass (Morone chrysops x Morone saxatilis) but have also been identified in many other fish species. Previous work demonstrated the broad antimicrobial activity of piscidins against Gram-negative and Gram-positive bacterial species. This study sought to determine the extent to which class I (striped bass piscidin 1, white bass piscidin 1 and striped bass/white bass piscidin 3) and class II (striped bass piscidin 4 and white bass piscidin 5) piscidins inhibit biofilm formation of different Gram-negative bacteria. In general, the class I and II piscidins demonstrate potent activity against Escherichia coli and Flavobacterium columnare biofilms. The class II piscidins showed more activity against E. coli and F. columnare isolates than did the class I piscidins. The piscidins in general were much less effective against inhibiting Aeromonas hydrophila and A. veronii biofilm growth. Only the class I piscidins showed significant growth inhibition among the Aeromonas spp. examined.