哈夫尼菌降解毒死蜱条件的优化及动力学模型建立

利用响应面法优化哈夫尼菌降解毒死蜱的条件,并建立了降解模型。采用Box-Behnken设计试验,以响应面法进行优化,结果表明,哈夫尼菌降解毒死蜱的最优条件为：蔗糖浓度0.31%,毒死蜱初浓度51.33mg·L-1,培养温度30.7℃,在该条件下理论预测毒死蜱降解率可达74.7%。通过假设和验证,得出哈夫尼菌降解毒死蜱为一级动力学模型,哈夫尼菌能水解毒死蜱P-O键,属一级酶促反应。     

Cricopharyngeal-laryngeal dysplasia in a horse with sudden clinical onset idiopathic laryngeal hemiparesis

A 7-year-old Thoroughbred racehorse developed loud exercise-related respiratory noises and exercise intolerance over a short period. Examination showed congenital cricopharyngeal-laryngeal dysplasia (rostral displacement of the palatopharyngeal arch) and also left sided idiopathic laryngeal hemiparesis, the latter appearing to be of recent clinical onset. The animal developed colic some months after laryngeal surgery and a nephrosplenic entrapment was surgically corrected. Aerophagia and regurgitation worsened after surgery and, after developing inhalation pneumonia, the animal was destroyed. Post-mortem examination confirmed the presence of idiopathic laryngeal hemiparesis and of cricopharyngeal-laryngeal dysplasia which had some previously undescribed laryngeal muscle abnormalities.     

Virulence factors and pathogenicity of Hafnia alvei for gilthead seabream, Sparus aurata L

Virulence factors (eae gene, haemolytic capacity, fimbriae, resistance to the bactericidal effect of serum, siderophore production) and pathogenicity for gilthead seabream, Sparus aurata L., were analysed for 23 Hafnia alvei strains. None of the strains used in LD50 studies were lethal for seabream at doses as high as >10(8) cfu mL(-1). In chronic challenge studies differences in severity of the inflammatory response were observed between strains. On the basis of correlation of the inflammatory response to different strains of H. alvei in seabream with those virulence factors studied, it was only possible to establish a positive correlation between pathogenicity and resistance to the bactericidal effect of fish serum. Gilthead seabream is thus a species with considerable resistance to experimental infection with H. alvei. The bacterium does, however, have the capacity to remain viable in seabream for up to 3 months, without any clinical signs. Hafnia alvei is a well-recognized human and animal pathogen. Thus, as the pathogen can coexist with aquaculture operations, cultured gilthead seabream could represent a risk to human health as a carrier in some circumstances.     

Recovery of Hafnia alvei from diseased brown trout,Salmo trutta L., and healthy noble crayfish,Astacus astacus (L.), in Bulgaria

Hafnia alvei was isolated in Bulgaria from healthy noble crayfish, Astacus astacus (L.), and then from farmed diseased brown trout, Salmo trutta L., with signs of haemorrhagic septicaemia. The isolates were identified initially with conventional phenotyping and commercial Merlin Micronaut and API 20E rapid identification systems, followed by sequencing of the 16S rRNA gene. Hafnia alvei Bt1, Bt2 and Aa4 were of low virulence to rainbow trout and brown trout, although cytotoxicity was demonstrated by Bt1 and Bt2, but not by Aa4.     

贵州中蜂蜂房哈夫尼菌的分离鉴定及药敏试验

为准确诊断贵州某蜂场发生的细菌性中蜂疾病,并提供防制方案,本试验进行了细菌分离纯化、形态学观察、生化试验,应用细菌16S rRNA基因通用引物进行基因扩增测序,测序结果在NCBI上进行比对分析,选取同源性较高的5个属的30株细菌的16S rRNA序列进行同源性分析并构建系统进化树,并对该分离菌进行动物回归试验和药敏试验。结果显示,分离菌为革兰氏阴性短杆菌,生化试验初步鉴定为蜂房哈夫尼菌;16S rRNA序列与哈夫尼杆菌属同源性最高,在97.0%~99.6%之间;遗传进化树表明,分离菌在哈夫尼菌菌属这一分支;动物回归试验显示,分离菌对中蜂有一定致病性,表明该蜂场受到蜂房哈夫尼菌感染,造成了蜜蜂的副伤寒;药敏试验结果表明,分离菌对青霉素、红霉素、克林霉素等耐药,对阿米卡星、复方新诺明、氧氟沙星等敏感。本试验结果为中蜂感染蜂房哈夫尼菌病的研究提供了一定参考,并能对蜂场提供合理用药意见。     

哈夫尼菌降解毒死蜱条件的优化及动力学模型建立

利用响应面法优化哈夫尼菌降解毒死蜱的条件,并建立了降解模型.采用Box-Behnken设计试验,以响应面法进行优化,结果表明,哈夫尼菌降解毒死蜱的最优条件为:蔗糖浓度0.31%.毒死蜱初浓度51.33 mg·L-1,培养温度30.7℃.在该条件下理论预测毒死蜱降解率可达74.7%.通过假设和验证,得出哈夫尼菌降解毒死蜱为一级动力学模型,哈夫尼菌能水解毒死蜱P-O键,属一级酶促反应.