为了探究从川南黑山羊体内分离获得的1株细菌LZS-01的致病性和生物学特性,本试验采用革兰染色、细菌形态观察、生化鉴定、16S rDNA基因序列分析、小鼠致病性试验和药敏试验对其进行研究.结果显示:菌株LZS-01为短杆状革兰阴性菌,16S rDNA基因扩增后得到的DNA片段长度为1 446 bp,与GenBank中波氏希瓦氏菌(Shewanella baltica)的同源性为100％,在系统进化树中与波氏希瓦氏菌(NCTC10737)聚为一支,综上结果推测该菌株为波氏希瓦氏菌;该菌株对小鼠致病性较强,可导致其肺泡壁增厚、肺泡腔狭窄,纤维样物质充满肺泡,肾小管上皮细胞水肿严重、管腔狭窄等;该菌株对环丙沙星、四环素等抗菌药物敏感,对氟苯尼考、青霉素和氧氟沙星等抗菌药物耐药.结果表明,波氏希瓦氏菌对动物具有一定致病性和耐药性.本试验结果为波氏希瓦氏菌感染性疾病的研究和临床防治积累了科学资料.

[Objectives]The purpose of this study was to explore the pathological and molecular mechanisms of kidney injury in goats caused by urea. [Methods]Nine healthy and disease-free Jianzhou Da’er goats were selected and randomly divided into 3 groups, including control group（C group）,5% urea group（U5 group）and 10% urea group（U10 group）. The feeding method was crude concentrate mixed feeding, and the urea was used to replace part of soybean meal concentrate feeding. Urea was not added to control group. The trial period was 21 days. At the end of the trial, blood samples were collected, serum blood ammonia levels were measured, the indicators of oxidative damage and iron ion content in kidney tissue were determined by biochemical and iron kit. The pathological damage of kidney tissue were observed by HE and Masson stain. The ultrastructure of renal tubular epithelial cells was observed by transmission electron microscope. The mRNA relative transcription level of ferroptosis-related genes in kidney tissue were detected by RT-qPCR. The expression level of recombinant glutathione peroxidase 4（GPX4）protein was detected by Western blot. [Results]Compared with the control group, the content of malonic dialdehyde（MDA）in the 5% urea group and the 10% urea group significantly increased（P＜0.01）,but the content of L-glutathione（GSH）,the activities of SOD（superoxide dismutase）and GSH-Px（glutathione peroxidase）significantly decreased（P＜0.01）. Meanwhile, the content of iron ions significantly increased（P＜0.01）. The epithelial cells of renal tubules were swollen, denaturated and necrotic. Collagen fibers were hyperplasia, and the mitochondria of renal tubular epithelial cells atrophied, cristae reduced, and membrane density was increased. The mRNA relative transcription level of FTH1（ferritin, heavy polypeptide 1）,VDAC3（voltage dependent anion channel protein 3）,p53（Tumor protein 53）and NCOA4（nuclear receptor coactivator 4）genes significantly increased（P＜0.01）. The mRNA levels and protein expression level of GPX4 significantly decreased（P＜0.05）. [Conclisions]The expression of NRF2 was inhibited when urea was added at high dose, initiating the mechanism of cellular iron death, causing oxidative stress in kidney and iron ion metabolism imbalance.