甜菜BvGSTU9基因的生物信息学及在镉胁迫下的表达分析

为了进一步研究甜菜谷胱甘肽转移酶BvGSTU9 (LOC104894060)在重金属胁迫过程中的功能。本研究以‘780016B/12优’为实验材料,对该基因序列特征、结构、功能进行预测分析,并利用qPCR检测该基因在不同浓度镉胁迫下的表达量变化。结果显示甜菜BvGSTU9基因全长925 bp,开放阅读框675 bp,编码了由224个氨基酸组成的不稳定膜外蛋白。BvGSTU9与菠菜、藜麦的氨基酸序列相似性较高,与系统发育进化树分析结果基本相符。二级和三级结构预测表明该基因主要由α-螺旋、β-折叠、延伸链及无规则卷曲组成。qPCR显示BvGSTU9基因在不同浓度的镉胁迫下均受到不同程度的诱导,因此可以推断甜菜BvGSTU9基因无论从结构还是功能上,与镉逆境胁迫存在着一定的应答关系。研究结果也为甜菜耐重金属镉机制研究提供参考依据。     

镉毒性研究进展

本文综述了动物生产领域对镉的研究结果。这些内容包括 :(1)镉的化学特性 ;(2)镉在自然界的分布 ;(3)镉的生物学作用 ;(4)镉在动物体内的吸收和排泄 ;(5)镉对动物的危害 ;(6)镉与其它物质之间的关系 ;(7)镉的需要量、中毒量及饲料中镉的最大允许量。     

A Prospective Study Of Intravenous Catheter Contamination

A one year prospective study was conducted to determine the association between intravenous catheter contamination and increased dwell time, and to identify any related risk factors. Intravenous catheters obtained from 23 cats and 98 dogs in the Intensive Care Unit at the Ontario Veterinary College with dwell times > 72 hours for the test group (n=58) and < 72 hours for a corresponding control group (n=63) were cultured between April 1991 and March 1992. One hundred and twenty one catheters were cultured, 16 jugular, 99 cephalic, and 6 saphenous. The overall contamination rate was 13 out of 121 catheters cultured (10.7%); 9/63 (14.3%) control and 4/58 (6.9%) test catheters. The bacteria isolated were E.aerogenes, S.aureus (3), P.aeruginosa, P.multocida, and Bacillus sp (7). The Bacillus sp positive catheters (5 control and 2 test) were placed during a five day period, and contaminated gauze squares were identified as the source of infection in these catheters. After these were removed from the study, the group infection rate was 6.9% control and 3.6% test. There was no significant difference between groups and no associated risk factors were identified. We conclude that intravenous dwell time need not be restricted to <72 hours.     

梅州市五华县石灰岩矿区土壤铅污染现状研究及改良对策

对梅州市五华县几个石灰岩矿区周边土壤中铅含量进行了测定，结果表明，污染土壤的铅含量远远超出了国家土壤环境质量三级标准（对土壤生态环境产生影响的最低浓度值），对生态产生影响。根据内梅罗污染指数评定得出，矿区土壤铅污染达到重污染的程度。提出了减轻铅污染对生态环境危害的控制污染源措施和改良对策。     

降低人造板热压机液压系统油液污染的探讨

车间粉尘与湖湿空气是人造板热压机液压系统油液外界污染的主要原因，通过构筑封闭式泵房，增设辅助油箱，改变没箱底部结构，设置排污，排水装置，可有效降低人造板热压机液压系统油液污染，改善液压系统性能，提高压机工作效率。     

Movement of Xanthomonas campestris pv. vitians in the stems of lettuce and seed contamination

Xanthomonas campestris pv. vitians , the causal agent of bacterial leaf spot of lettuce (BLS), can be seedborne, but the mechanism by which the bacteria contaminates and/or infects lettuce seed is not known. In this study, the capacity of X. campestris pv. vitians to enter and translocate within the vascular system of lettuce plants was examined. The stems of 8- to 11-week-old lettuce plants were stab-inoculated, and movement of X. campestris pv. vitians was monitored at various intervals. At 4, 8, 12 and 16 h post-inoculation (hpi), X. campestris pv. vitians was recovered from 2 to 10 cm above (depending on stem length) and 2 cm below the inoculation site. Xanthomonas campestris pv. vitians was also recovered from surface-disinfested stem sections of spray-inoculated plants. Together, these results are consistent with X. campestris pv. vitians invading and moving systemically within the vascular system of lettuce plants. To investigate the mechanism of seed contamination, lettuce plants at the vegetative stage of growth were spray-inoculated with X. campestris pv. vitians and allowed to develop BLS. Seed collected from these plants had a 2% incidence of X. campestris pv. vitians external colonization, but no bacteria were recovered from within the seed.     

抗生素工业化生产中一级种子罐染菌原因及解决方法

抗生素工业化生产中,菌种往往需要扩大繁殖到一定的数量后再进入发酵罐.在一级种子制备过程中,引起染菌的因素很多,极大地影响了抗生素生产的产量和质量.解决一级种子罐染菌的方法,除制定科学的岗位SOP并不断提高操作者的技能外,更重要的是要加强工艺管理,树立以预防为主的思想,根据微生物特性,强化环境清洁,加强设备清洁、维修,操作时实行定人、定操作.     

Reliably colonising broiler chickens with Campylobacter spp. using a litter-based method

ABSTRACT

1. Chicken-associated Campylobacter spp. are the cause of most food poisoning cases in Europe. In order to study the host–pathogen interactions, a reliable and reproducible method of colonising chickens with the bacteria is required.

2. This study aimed to identify a more appropriate and less invasive method of colonisation (cf. gavaging) by seeding bedding material (litter) that commercial chickens are kept on with a mixture of Campylobacter spp., broth and faeces.

3. The first phase of the study tested the longevity of Campylobacter spp. recovery in seeded litter over 24 h: significantly more Campylobacter spp. was recovered at 0 or 3 h post-seeding than at 6 and 24 h post-seeding, indicating that the pathogen can survive to detectable levels for at least 3 h in this environment.

4. In the second phase, three groups of 10 broiler chickens (negative for Campylobacter spp. prior to exposure) were exposed at 21 days of age to one of three different Campylobacter jejuni and C. coli mixes (A, B, C), using the method above. At 28 days of age, birds were euthanised by overdose of barbiturate or cervical dislocation, and livers and caeca removed for Campylobacter spp. assessment.

5. All liver and 28/30 caeca samples tested positive for Campylobacter spp., with mix A and C giving higher counts in the caeca than mix B. The method of euthanasia did not affect Campylobacter spp. counts.

6. In conclusion, a successful method for reliably colonising broiler chickens with Campylobacter spp. has been developed which negates the need for gavaging and is more representative of how contamination occurs in the field.