暹罗鳄外周血白细胞提取物抗海豚链球菌感染的效果

通过细胞破碎和沉淀的方法从暹罗鳄(Crocodylus siamensis)外周血白细胞中获得提取物,并将此提取物以3种不同的方式注射小鼠,测定其在小鼠体内抗御海豚链球菌感染的效果。实验结果表明,若用海豚链球菌以腹腔注射感染小鼠,小鼠表现出明显病理症状,然后用不同浓度(2.2×103、2.2×102、2.2×101μg/ml)的提取物以腹腔注射小鼠,可使小鼠分别获得77.8％、55.6％、44.4％的相对保护率;若将海豚链球菌与不同浓度(2.2×103、2.2×102、2.2×101μg/ml)的提取物在体外等体积混合,然后将混合物以腹腔注射小鼠,可使小鼠分别获得55.6％、88.9％、77.8％的相对保护率;若将海豚链球菌以肌肉注射小鼠左腿,同时以不同浓度(2.2×103、2.2×102、2.2×101μg/ml)的提取物以肌肉注射小鼠右腿,可使小鼠分别获得77.8％、66.7％、44.4％的相对保护率。本实验的结论是：暹罗鳄外周血白细胞内存在一种或数种高效的抗菌物质,在小鼠体内能有效的防御由某些细菌导致的感染。     

暹罗鳄外周血白细胞提取物抗菌活性的初步研究

用离心和细胞破碎沉淀法提取暹罗鳄外周血白细胞的抗菌活性物质,测定其对10种细菌的体外抗菌活性。结果表明：暹罗鳄外周血白细胞提取物对埃希氏大肠杆菌、海豚链球菌、多杀性巴斯德菌、温和气单胞菌、金黄色葡萄球菌、嗜水气单胞菌、副溶血弧菌、溶藻弧菌、创伤弧菌、霍乱弧菌10种细菌均有一定的抗菌效力;其中,对海豚链球菌的抗菌效力最强,抑菌圈达22．1mm;对大肠杆菌的抗菌效力次之,抑菌圈达21．7mm;对霍乱弧菌的抗菌效力较弱,抑菌圈为7mm。实验还测定了理化因子对暹罗鳄外周血白细胞提取物抗菌活性的影响,发现其具有酸溶性、EDTA敏感性和热稳定性等特点。据此特点,初步确定暹罗鳄外周血白细胞中所含的抗菌活性物质是抗菌肽。比较了暹罗鳄外周血白细胞和密西西比红耳龟、花田鸡外周血白细胞提取物的抗菌效力的强弱,发现前者对于实验所用10种细菌的抗菌效力明显强于后两者;其中,对链球菌的抗菌效力,暹罗鳄外周血白细胞提取物最强,抑菌圈达21．3mm,密西西比红耳龟外周血白细胞提取物次之,抑菌圈为5．3mm,花田鸡白细胞提取物最弱,抑菌圈为0．67mm。说明暹罗鳄外周血白细胞中存在一种或数种具有广谱、高效的抗菌活性物质。     

促生细菌Bacillus sp. QN2MO-1的鉴定及对番茄生长的影响

为分离和鉴定具有促生作用的内生菌,开发潜在功能的微生物菌株,本研究以诺尼（Morinda citrifolia L.）为研究对象,从植株不同组织中共分离得到621株内生细菌,经复筛得到具有促生和解磷作用的菌株,命名为QN₂MO-1。基于菌株的生理生化分析和16S rDNA的序列比对,该内生细菌与Bacillus siamensis KCTC 13613^T（AJVF01000043）具有99.04%的同源性。药敏性分析显示,该菌对青霉素、硫酸链霉素和氨苄西林具有明显的抗性。QN₂MO-1可促进番茄种子的萌发;与对照相比,5%菌体发酵液处理能显著提高植株的生长。     

Release of critically endangered crocodiles: Development and application of a food web approach to determine suitability of release habitat

相似文献   

六种竹材灰分及二氧化硅含量分析

以3年生勃氏甜龙竹、龙竹、麻竹、泰竹、小叶龙竹与黄皮绿筋竹的竹叶与竹秆为研究对象,分析了6个竹种竹秆及竹叶中的灰分含量及二氧化硅含量。结果表明:6种竹材间无论是竹叶还是竹秆,其灰分含量及二氧化硅含量均存在明显差异,其原因可能为竹种及生长环境的差异所致;同一竹种竹叶中的灰分含量和二氧化硅含量大于竹秆中的含量;竹秆不同部位二氧化硅含量表现为自顶部至基部逐渐减小的变化趋势。     

Isolation and characterisation of crocosin,an antibacterial compound from crocodile (Crocodylus siamensis) plasma

An antibacterial compound from crocodile blood was partially purified and functionally characterised. The freshwater crocodile (Crocodylus siamensis) plasma with antibacterial activity was partially purified by using a centrifugal concentrator and reverse phase high powered liquid chromatography, and designated as crocosin. Crocosin exhibits antibacterial activity toward Salmonella typhi and Staphylococcus aureus. Crocosin is thermostable and resistant to pronase digestion. The structure of crocosin analyzed by mass spectrometry contains repeating units of 94 and 136 m/z. Scanning electron microscopy indicates that crocosin probably penetrates progressively into cytoplasm space, perturbing and damaging bacterial membranes. Crocosin may provide an early defense mechanism toward bacterial infection in freshwater.     

Modulation of the response of rainbow trout (Oncorhynchus mykiss Walbaum) to confinement, by an ectoparasitic (Argulus foliaceus L.) infestation and cortisol feeding

The effects of a 21 day infestation with the ectoparasite Argulus foliaceus on the response of rainbow trout Oncorhynchus mykiss to an acute stressor (confinement) were investigated. Fish were divided into a control and two parasitized groups, with one parasitized group having received cortisol feeding 72 and 24 h before infection. Prior to confinement only control fish showed a significant increase in body mass and condition factor. Following 4 h confinement, plasma glucose levels in the normal- fed/infested group were significantly higher than in the controls, while the cortisol-fed/infested group had significantly lower plasma levels of adrenocorticotropic hormone (ACTH) and glucose. Both infested groups, but not controls, had higher plasma ACTH and cortisol levels 48 h after confinement when compared with their pre-confinement levels. Stressor-induced immunomodulation was more evident in the parasitized fish after confinement, as was concluded from decreased lysozyme activity, alternative complement activity and oxygen radical production either immediately after, or 48 h post 4 h confinement. Circulating lymphocyte numbers were significantly reduced in the control and normal-fed/infested fish. Results indicate that low ectoparasitic infestations can, for a prolonged period, lead to a stress experience with effects that impair the response to subsequent stressors. Such effects may be further confounded by a previous elevation of plasma cortisol levels.     

芽胞杆菌FJAT-28592抗真菌脂肽的研究

为研究产表面活性剂芽胞杆菌(Bacillus)的生防作用,本研究筛选了一株能够抑制尖孢镰刀菌(Fusarium oxysporum)的芽胞杆菌FJAT-28592,经16S rRNA鉴定为暹罗芽胞杆菌(Bacillus siamensis.菌株FJAT-28592的生长温度范围为25～50℃,最佳生长温度为35℃;pH 5.0～9.0,最佳pH 6.0～8.0;可在NaC1浓度为0～6％的条件下生长,最佳生长盐浓度为2％.透射电镜显示,菌株呈杆状,具有鞭毛,宽度为0.76～0.94 μm,长度为1.76～2.94 μm.暹罗芽胞杆菌FJAT-28592发酵液和提取的发酵液粗产物对尖孢镰刀菌有很好的抑菌效果.通过血平板和排油圈实验,初步认定暹罗芽胞杆菌FJAT-28592能分泌表面活性剂至发酵液.通过酸沉淀处理,甲醇和丙酮抽提,分离和收集发酵液中表面活性剂.高效液相色谱(high performance liquid chromatography,HPLC)对初步纯化的粗品与iturin A的标准品进行分析,粗品与标准品iturin A的主峰保留时间均为10.687 min,初步判断粗品含有iturinA.克隆iturinA类脂肽合成的相关基因,获得丙二酰辅酶a转酰酶(malonyl-CoA-transacylase,ituD)和4’-磷酸泛酰巯基乙胺基转移酶(4’-phosphate generic acyl cysteamine transferase,lpa-14)基因序列,得出此表面活性剂为iturinA类的脂肽.本研究为芽胞杆菌生防菌的开发,分析获得抑菌物质提供基础资料.     

The epidemiology of Argulus spp. (Crustacea: Branchiura) infections in stillwater trout fisheries

Problem infections caused by species of the crustacean ectoparasite, Argulus, in UK stillwater trout fisheries appear to have increased in recent years. A cross-sectional study of 77 such fisheries was conducted to establish the perceived problem and the extent and severity of this problem, and to identify associated risk factors. An interview-based study was conducted in 2001 using a standardized questionnaire based on the management and infection status of each fishery in the previous year. Logistic regression was used to identify potential risk factors. Argulus spp. were perceived to cause economic losses in infected fisheries through a reduction in the number of anglers due to reduced aesthetic appeal and catchability of fish. Of the sites studied, 29% experienced such a problem infection in 2000. Argulus foliaceus was identified in all but one case and was found to be widely distributed throughout the UK. The remaining case was identified as Argulus coregoni. Three risk factors were associated with problem infections: the presence of an algal bloom, slow rates of stock turnover and whether water level dropped by <1 m during the summer months.