共查询到20条相似文献,搜索用时 62 毫秒
1.
2.
3.
益生乳酸杆菌抑制大肠杆菌的研究 总被引:8,自引:0,他引:8
本试验在分离选育出一批抗逆性较强的乳酸杆菌之后 ,测定了从胃粘膜分离筛选出的三株乳酸杆菌的乳酸产量、乳酸杆菌前期代谢产物的抑菌作用和乳酸杆菌及其代谢产物的协同抑菌作用。结果表明 ,乳酸杆菌代谢产物中乳酸不是唯一起抑菌或灭菌作用的代谢物。乳酸杆菌代谢产物对不同血清型大肠杆菌的抑制效果和乳酸杆菌及其代谢产物联合对大肠杆菌的抑菌作用相似 ,即抑制或杀灭大肠杆菌K88和K99较强 ,而对 987P的抑制作用较弱。同时 ,乳酸杆菌的菌体及其代谢产物对大肠杆菌具有一定的协同抑制作用。 相似文献
4.
为了探讨唾液乳杆菌的生长特性及抑菌作用,测定2株唾液乳杆菌的生长曲线,并选用口腔变形链球菌、牙龈卟啉单胞菌及金黄色葡萄球菌为指示菌,采用牛津杯法进行体外抑菌实验.结果表明:2株唾液乳杆菌分别在接种2h和4h进入对数生长期,8h进入对数生长末期,14h和16h进入稳定期;2株唾液乳杆菌菌液及代谢产物对口腔变形链球菌、牙龈卟啉单胞菌及金黄色葡萄球菌均有抑菌作用,对口腔变形链球菌及牙龈卟啉单胞菌的抑菌作用强于金黄色葡萄球菌;2株唾液乳杆菌菌体及调整pH值为7.0的代谢产物没有抑菌作用;2株唾液乳杆菌的抑菌能力主要来自菌体的代谢产物,代谢产物中起抑菌作用的成分为酸或酸依赖性物质. 相似文献
5.
6.
枯草芽胞杆菌L7是从牛粪中选出的,它的代谢产物中的抑菌物质对多种病原菌具有强烈的抑制作用。通过对其抑菌物质产生的发酵条件研究认为,最佳发酵条件为pH值7.0、接种量4%、30℃恒温振荡培养箱培养,发酵时间约60h。其代谢产物中的抑菌物质在80~121℃下30min稳定,pH值在6.0~10.0范围内稳定,光照2~6h后抑菌活性下降。结论:菌株L7的发酵产物具有较强稳定性,可置避光、pH值中性、常温环境中短期保存,经提高活性、纯化等处理后可能作为新型天然防腐剂应用于食品领域,或应用于抗感染微生态制剂的生产。 相似文献
7.
8.
9.
10.
《饲料研究》2016,(3)
为研究从内蒙古锡林郭勒盟地区酸马奶中提取的植物乳杆菌DSM20174的抑菌能力和抑菌活性物质的特性,采用牛津杯法将植物乳酸杆菌的菌液和发酵上清液在3种处理方式下,对牛源野生致病性大肠杆菌O78的抑菌效果进行分析。结果表明:植物乳杆菌DSM20174的菌液和发酵上清液即使在121℃,30 min处理后,抑菌直径达仍达到14.10和14.40 mm;在p H=2.0时,菌液和发酵上清液的抑菌直径为21.9和22.1 mm;而当p H=4.0时抑菌活性明显下降,前者为14.8 mm,后者为14.9 mm;p H 5.0~7.0时,抑菌直径为0;二者分别经胰蛋白酶、胃蛋白酶和木瓜蛋白酶的反应后,处理前组和处理后组抑菌直径变化均不明显。在3种处理方式下,发酵上清液的抑菌直径均大于同组的菌液的抑菌直径。因此,植物乳杆菌DSM20174是一种较好的抑菌活性物质和热稳定性物质,随着温度和时间的升高,抑菌活性降低。其在p H5.0的条件下有抑菌活性,随p H的升高抑菌活性降低,p H越小时抑菌活性越强,p H≥5.0时失去抑菌活性。对蛋白酶不敏感。在相同条件下,发酵上清液的抑菌作用强于菌液。 相似文献
11.
12.
13.
魏静 《四川畜牧兽医学院学报》2009,(4):28-32
在现代法律秩序中,商会自治规范是制定法的基础和必要的补充,甚至在某些方面替代了制定法;商会自治规范主要包括商会组织规范、行为规范、惩罚规范以及争端解决规范等;其效力仅及于其内部成员;商会自治规范和制定法之间存在冲突,但也存在整合的基础。 相似文献
14.
本文概述了猪的毛色类型、猪的毛色遗传模式,着重综述了猪毛色基因分子基础的研究进展,指出存在问题并就未来发展方向做了思考。 相似文献
15.
16.
以国际标准强毒R株人工感染非免疫产蛋鸡,定时扑杀,分别从鼻窦、眶下孔、气管、肺、气囊、卵巢和输卵管分离MG,并收集感染鸡所产蛋分离MG。结果表明,人工感染48小时后上、下呼吸道及肺已被全面感染,96小时气囊已被感染,120小时输卵管已能分离到MG,卵巢始终分离不到MG。人工感染鸡自144小时便能在其所产蛋中分离出MG。药物治疗能在72小时内消除感染,油乳剂苗则需24天后逐渐降低蛋内MG分离率,药物卵内注射、种蛋药浴、高温处理均能杀死卵内MG,但以研制的种蛋浸泡剂药浴效果为最好。 相似文献
17.
REASONS FOR PERFORMING STUDY: Centesis of the bicipital bursa using an 8.9 cm long spinal needle has been reported but the alternative of employing a 3.8 cm long hypodermic needle requires validation. OBJECTIVE: To compare the efficacy of 2 different methods of centesis of the bicipital bursa and to evaluate the usefulness of ultrasonographic imaging to determine the location of solution administered when centesis of the bursa is attempted. METHODS: For Trial 1, 6 clinicians, who had no previous experience of centesis of the bicipital bursa, attempted to inject a solution composed of an aqueous radiopaque contrast medium and physiological saline solution (PSS) into the bicipital bursae of 2/12 horses using the previously described distal approach to inject one bursa and a proximal approach to inject the contralateral bursa. The bicipital tendon and bursa were examined ultrasonographically before and after injection; and both shoulders were examined radiographically to identify the location of the medium. In Trial 2, another 6 clinicians, also with no previous experience of centesis, repeated Trial 1, using 6 horses, but the radiopaque contrast medium was mixed with air instead of PSS. RESULTS: Accuracy of centesis using the proximal approach was 39% and that of the distal approach 28%. Ultrasonographic examination of the shoulder allowed the location of solution and air to be accurately predicted in all 12 shoulders examined. CONCLUSIONS: Clinicians who have had no previous experience performing centesis of the bicipital bursa are unlikely to be successful in centesis using either approach. Radiographic examination after injecting a radiopaque contrast medium may be necessary to assess the success of centesis especially if bursal fluid is not obtained during centesis. Injecting air along with the radiopaque contrast medium provides more accurate ultrasonographic confirmation of centesis and better radiographic definition than does injection without air. 相似文献
18.
19.
20.
Effects of size of ingestively masticated fragments of plant tissues on kinetics of digestion of NDF
Ingestively masticated fragments were collected and sized via sieving. Different sizes of esophageal masticate and ruminal digesta fragments, and ground fragments of larger masticated pieces were incubated in vitro, and undigested NDF remaining at intervals of up to 168 h of incubation was determined. The ruminal age-dependent time delay (tau) for onset of digestion of NDF was positively correlated (P < 0.004) with the mean sieve aperture estimated to retain 50% of the fragments between successive sieve apertures (MRA). Degradation rate of potentially degradable NDF (PDF) and level of indigestible NDF were not related (P > 0.10) to MRA of masticated and ground fragments. Estimates of tau were positively related to MRA, with slopes of bermudagrass < corn silage < ruminal fragments of corn silage. It was concluded that fragment size-, and consequently, ruminal age-dependent onset of PDF degradation of a mixture of different fragment sizes results in an age-dependent rate of degradation of the more rapidly degrading of two subentities of PDF. Models are proposed that assume a tau before onset of simultaneous degradation of PDF from two pools characterized as having gamma-modeled age-dependency and age-constant rates. The ruminal age-dependent pool seems to be associated with the faster-degrading pool, and its rate parameter increases with range in MRA in the population of fragments. Conceptually, the ruminal age-dependent rate parameter for PDF degradation seems to represent a composite of several effects: 1) effects of the size-dependent tau; 2) range in MRA of the population of ingestively masticated fragments; and 3) subentities of PDF that degrade via more rapid age-dependent rates compared with subentities of PDF that degrade via age-constant rates. The estimated fractional rates of ruminative comminution of ingestively masticated fragments (0.060 to 0.075/h) were of a magnitude similar to the mean fractional rates of PDF digestion (0.030 to 0.085/h), which implies that ruminative comminution may be first-limiting to fractional rate of PDF digestion. The in vivo roles of ingestive and ruminative mastication of fragments on PDF degradation must be considered in any kinetic system for estimating PDF digestion in the rumen. These results and others in the literature suggest that the rate of surface area exposure rather than intrinsic chemical attributes of PDF may be first-limiting to degradation rate of PDF in vivo. 相似文献