耐受高浓度吉他霉素的发酵乳杆菌的诱变筛选

试验以一株发酵乳杆菌为出发菌株,通过不同浓度吉他霉素诱变,从而筛选出一株耐受60mg/L吉他霉素的乳酸菌。该株乳酸菌具有耐受吉他霉素、性状稳定及容易在猪肠道定殖的优点。通常饲料中吉他霉素的添加量为30mg/kg,试验的产物菌株在该浓度下可完全不受抑制,从而保证肠道内乳酸菌群在抗生素使用过程中不被破坏。     

东北地区传统手工奶酪中具有益生特性乳酸菌的分离与筛选

为了筛选出既具有高抗氧化活性又能耐酸、耐胆盐、耐胰蛋白酶的优良菌株,试验以东北地区传统手工奶酪为分离源,采用常规微生物学方法分离纯化乳酸菌,并结合镜检观察、生化试验以及16S r DNA基因序列分析对菌株进行鉴定,筛选出产酸性能良好的乳酸菌,并对其进行耐酸、耐胆盐、耐胰蛋白酶、抑菌、抗氧化等特性试验。结果表明:筛选出的59株产酸性能良好的乳酸菌中,有19株耐酸、耐胆盐、耐胰蛋白酶且对金黄色葡萄球菌、粪肠球菌、沙门氏菌、绿脓杆菌和李氏杆菌均有抑制作用,其中筛选出的植物乳杆菌B5-1-1-1和干酪乳杆菌B4-2-11-5不仅具有还原性,而且在清除羟基和自由基方面均具有较高能力,有望成为具有益生特性的乳酸菌资源,从而为东北地区奶酪选育优良乳酸菌奠定基础。     

新疆拜城赛里木镇传统发酵酸乳中优势菌株的胃肠道耐受特性

通过体外耐酸、耐胆盐实验,从新疆拜城赛里木镇传统拉丝酸乳中的优势乳酸菌中筛选出耐受性和优良益生特性较强的乳酸菌菌株.结果表明:筛选出来的9株乳酸菌,在pH 2.0的条件下表现出-强的耐受能力,S5-8和S2-1L用人工胃液处理后的活菌数量在108 CFU/mL以上,其中S5-8有明显的增长趋势,其他7株菌株活菌数量在107CFU/mL以上,远远超过了106 CFU/mL以上的临界值,对9株强耐酸性乳酸菌进行耐胆盐实验.     

新发现具有治疗鸡胃肠道疾病潜力的乳杆菌

<正>澳大利亚国立大学科研人员从鸡胃肠道内分离到3株乳酸菌,分别为敏捷乳杆菌(La3)、阴道乳杆菌(Lv5)和卷曲乳杆菌(Lc9)。由于乳酸菌正常存在于鸡胃肠道内,研究人员试图利用这些原生菌株来传     

鸡源乳杆菌的分离鉴定及其益生特性研究

利用选择性培养、革兰氏染色、芽孢染色、糖发酵试验、经典生理生化试验、耐酸和耐胆盐试验等方法,成功地从健康鸡的肠道中分离、鉴定并筛选出1株耐酸和耐胆盐能力较强的乳杆菌,命名为乳杆菌L3株。采用雏鸡安全性试验和肠黏液糖蛋白黏附性试验对乳杆菌L3株的安全性和黏附能力进行检测,证明所筛选的乳杆菌不仅对酸和胆盐的耐受性较好,且具有良好的安全性和肠道黏附能力。     

鸡源乳酸菌细菌素的分离筛选及鉴定

为了分离鉴定产乳酸菌细菌素,采用双层琼脂扩散法,对从健康鸡肠道内容物分离到的68株乳酸菌进行筛选,获得对大肠杆菌、金黄色葡萄球菌、鸡白痢沙门菌均有抑制作用的17株乳酸菌,在排除酸、过氧化氢等因素作用后仍具有较强抑菌活性,表明发酵液中还有其他抑菌活性物质的存在,用蛋白酶处理上清液后有6株菌的抑菌效果消失,表明抑菌物质具有蛋白质性质,是一种细菌素类物质。筛选出的菌株所产抑菌物质是一种广谱细菌素,它们对革兰阳性菌和革兰阴性菌均具有较强抑制效果。结合形态鉴定、生理生化特性试验以及16S rRNA序列同源性分析鉴定菌株LABJN02、LABJN05、LABJN06和LABJN14分离菌为唾液乳杆菌,LABJN16为约氏乳杆菌,LABJN31为卷曲乳杆菌。细菌素作为潜在的抑菌物质,与其产生菌一起在平衡肠道菌群中具有重要意义。     

健康动物肠道源产窄谱细菌素乳酸菌的筛选鉴定

从健康猪、鸡、兔新鲜粪便及鸡肠道内容物等78份样品中分离乳酸菌,以大肠杆菌、李氏杆菌、金黄色葡萄球菌作为指示菌筛选有明显抑菌活性的菌株,同时进行产细菌素的乳酸菌筛选,并测定抑菌谱;进一步通过生化试验,并结合16S rRNA基因测序结果确定菌株的种类,采用溶血试验和动物试验确定分离菌株的安全性。结果表明,在分离得到的30株乳酸菌中,共有8株对指示菌有抑制作用,其中1株为产窄谱细菌素的短乳杆菌。本研究为下一步探讨产细菌素短乳杆菌作为天然防腐剂和抗菌剂提供了材料。     

牛瘤胃乳酸菌的分离与鉴定

为分离筛选用于牛活菌制剂的乳酸菌菌株,本试验采用API 50CHL对从牛瘤胃中分离的60株乳酸菌进行生化鉴定,对鉴定出的菌株进行耐酸、耐碱、耐氧、生长温度、耐药和抑菌性测定。结果显示,经生化鉴定出的3株乳酸菌分别为嗜酸乳杆菌(L.acidophilus)、发酵乳杆菌(L.fermentum)和乳明串珠菌(L.holzapfelii),分别命名为L1、L2和L3。其中,L1耐酸性最强,L2耐碱性最强,L1在37~40℃均生长良好且兼性厌氧;L1、L2、L3耐药率分别为80%、67%、53%;3株乳酸菌对大肠杆菌和金黄色葡萄球菌均有不同程度的抑制作用;L1抑菌效果最好,抑菌直径为18.3mm和16.4mm。结果表明,L1、L2可作为抗性乳酸菌活菌制剂的候选菌株。     

牛瘤胃乳酸菌的分离与鉴定

为分离筛选用于牛活菌制剂的乳酸菌菌株,试验采用API 50CHL对从牛瘤胃中分离的60株乳酸菌进行生化鉴定,对鉴定出的菌株进行耐酸耐碱、生长温度、耐氧、耐药和抑菌性测定。结果显示,经生化鉴定出的3株菌分别为嗜酸乳杆菌（L.acidophilus）、发酵乳杆菌（L.fermentum）和乳明串珠菌（L.holzapfelii）,分别命名为L1、L2和L3。其中,L1耐酸性最强,L2耐碱性最强,L1在37～40 ℃之间均生长良好且兼性厌氧;L1、L2、L3耐药率为60%～100%;3株乳酸菌对大肠杆菌和金黄色葡萄球菌均有不同程度的抑制作用,其中L1抑菌效果最好,抑菌圈直径分别为18.30和16.40 mm。提示,L1、L2可作为抗性乳酸菌活菌制剂的候选菌株。     

高寒地区菊芋青贮物料耐低温乳酸菌的筛选与鉴定

为筛选可提升高寒地区菊芋(Helianthus tuberosus)青贮发酵品质的耐低温乳酸菌,本研究以‘青芋2号’菊芋青贮物料为材料,利用平板培养法分离乳酸菌株,分析菌株生理生化特性,并通过16S rRNA测序进行菌株种属鉴定。结果表明,菊芋青贮物料中共分离得到34株乳酸菌株,经低温及生理生化筛选获得13株耐低温乳酸菌株,包括11株同型发酵乳酸菌和2株异型发酵乳酸菌,其耐酸性和耐盐性均较强;经产酸和生长能力对比,GN02菌株生长最快(OD=2.63),GN10菌株具有更强的产酸能力(pH=3.59),XN25菌株兼具较强的生长和产酸能力;16S rRNA测序鉴定出9株植物乳杆菌(Lactiplantibacillus plantarum)、1株戊糖乳杆菌(Lactiplantibacillus pentosus)、1株棒状乳杆菌(Lactiplantibacillus coryniformis)、1株短乳杆菌(Lactiplantibacillus brevis)及1株无法鉴定。本研究筛选出适合高寒地区菊芋青贮发酵的耐低温植物乳杆菌、戊糖乳杆菌、短乳杆菌各1株。     

In vitro adhesion of an avian pathogenic Escherichia coli O78 strain to surfaces of the chicken intestinal tract and to ileal mucus

The role of fimbria in adherence of an avian pathogenic Escherichia coli (APEC) O78 strain 789 to chicken intestine was studied. Bacterial adhesion to tissue sections representing the regions within the chicken intestinal tract was determined by using immunohistochemical methods. E. coli 789 grown to express the type 1 fimbria adhered efficiently to the crop epithelium, to the lamina propria of intestinal villi, and to the apical surfaces of both the mature as well as the crypt-located enterocytes in intestinal villi, whereas no adhesion to mucus-producing goblet cells was detected. The adhesion was inhibited by mannoside and the role of type 1 fimbriae in the observed adhesion was confirmed with a recombinant strain expressing type 1 fimbriae genes cloned from E. coli and Salmonella enterica. E. coli 789 strain grown to favor AC/I fimbriae expression as well as the recombinant E. coli strain expressing the fac genes adhered to goblet cells but only poorly to the other epithelial sites. E. coli strain 789 as well as S. enterica serovar Typhimurium IR715 and S. enterica serovar Enteriditis TN2 strains were able to multiply in ileal mucus medium. The type 1 fimbria expressing bacteria adhered to the ileal mucus, whereas the AC/I fimbriated strains showed poor adherence to the mucus. The adhesion of E. coli 789 onto the crop epithelium and the follicle associated epithelium of the chicken ileum was efficiently inhibited by an adhesive strain ST1 of Lactobacillus crispatus isolated from chicken, whereas poor inhibition of E. coli adherence was observed with the weakly adhesive L. crispatus strain 134mi. The type 1 fimbriae may be important in colonization of the chicken intestine by APEC and Salmonella.     

不同来源乳酸菌的分离与鉴定

Six strains of Lactobacillus were isolated from traditional indigenous dairy products, piglet’s feces and chicken intestine, designated as LS, LT, LJ1, LJ2, LZ1 and LZ2， respectively. Identifications were done according to bacteria morphology, physiological and biochemical properties,16S rDNA sequence homology analysis, and their characteristics were researched. The results showed that LS, LT, LJ1 and LZ2 strains were Lactobacillus brevis, LJ2 strain was Enterococcus faecium, LZ1 strain was Lactobacillus acidophilus. All of the six strains had obvious bacteriostasis effect on Listeria monocytogenes, Salmonella typhimurium, Escherichia coli and Staphylococcus aureus.     

健康鸡嗉囊和盲肠内容物正常菌群的分离与鉴定

用血琼脂平板和乳清琼脂平板，采用集性没食子酸厌氧培养法，从健康非免疫产蛋母鸡的嗉囊和盲肠内容物中分离出正常菌群，地其中２１株瘘性厌氧的无芽胞杆菌和球菌，从革兰氏染色特性、形态特性、需氧生长条件和生化反应等方面进行了初步鉴定。结果其中有类肠膜明串珠菌１株，肠膜明串珠菌１株，粪链球菌３株，屎锭球菌１株，鸡肠链球菌１少酸链力３株，乳链球菌１株，假长双歧杆菌１株，星状双歧杆菌１株，嗜酸乳杆菌１株，嗜粪乳杆     

Isolation of surface (S) layer protein carrying Lactobacillus species from porcine intestine and faeces and characterization of their adhesion properties to different host tissues

Surface-layer proteins (Slps) of lactobacilli have been shown to confer tissue adherence. This study aimed to isolate and identify Slps carrying Lactobacillus species from the porcine intestine and faeces and to characterize these S-layer-expressing strains for their ability to adhere to the pig and human intestinal cells and to extracellular matrix (ECM) proteins. In total 99 strains, putatively belonging to the genus Lactobacillus, were isolated as pure cultures. SDS-PAGE and a gene probe specific for the Lactobacillus brevis ATCC 8287 S-layer protein gene (slpA) were used to screen the presence of strains possessing putative Slps. Eight of the 99 pure cultures exhibited Slps according to the SDS-PAGE analyses. In these strains the presence of genes encoding Slps was confirmed by PCR and partial sequencing. Only one isolate of the 99 strains gave a positive hybridisation signal with the L. brevis slpA probe but did not appear to produce S-layer protein. Their taxonomic identification, based on phenotyping and the 16S rRNA sequences, revealed that the eight S-layer protein-producing strains were closely related to Lactobacillus amylovorus, Lactobacillus sobrius and Lactobacillus crispatus. The strain with the slpA positive hybridisation result was identified as Lactobacillus mucosae. The SDS-extractable protein profile, the size of the putative S-layer protein and binding capability of the strains varied greatly, even among the isolates belonging to the same Lactobacillus cluster. Removal of the intact Slps from the bacterial surface by extraction with guanidine hydrochloride reduced the adhesion of some strains to fibronectin and laminin, whereas, the adhesiveness to laminin increased with some strains.     

猪源乳酸杆菌的分离鉴定及生物学特性分析

乳酸杆菌制剂可以替代抗生素,用于预防和治疗细菌性腹泻。为获取可作为微生态制剂的候选菌株,从健康仔猪肠道分离到5株乳酸杆菌,经抑菌试验、生长曲线测定、耐酸、耐胆盐、耐胰酶试验等,筛选到1株对大肠杆菌、沙门氏菌、金黄色葡萄球菌等致病菌有较好的抑制作用,对低pH值、高胆盐、胰酶均有一定耐受能力的乳酸杆菌,命名为LY7。经PCR鉴定,该菌株为约氏乳杆菌。     

三叶草根际溶磷菌溶磷及分泌IAA能力测定

为了获得优良的菌株资源,采用溶磷圈法、钼锑抗比色法和Spot、S2比色法,定性、定量测定了分离自三叶草根际10株溶磷细菌的溶磷和分泌植物生长激素(IAA)的能力,结果表明:各菌株在PKO无机磷培养液中的有效磷增量在106.63～666.01mg/L(P<0.05),菌株ls1-3有效磷增量最大;各菌株在蒙金娜有机磷培养液中的有效磷增量在0.32～58.42mg/L(P<0.05),菌株lhs11有效磷增量最大;有些菌株既能溶解无机磷,又能溶解有机磷,如菌株lhs4和lhs11;有些菌株能溶解无机磷,但无溶解有机磷的能力,如菌株ls1-3和ls1-5。除3个菌株(ls2-11、ls2-16和ls3-2)外,其他菌株都能分泌IAA,分泌量在0.36～20.39mg/L(P<0.05),菌株ls3-5分泌能力最强(20.39μg/mL)。菌株ls1-3、ls2-3、ls3-5、lhs4和lhs11有望作为研制微生物肥料的优良菌株。     

分离自牧草根际四株促生菌株(PGPR)互作效应研究

利用钼蓝比色、显色和Salkowski比色等方法测定了筛选自苜蓿、白三叶和红三叶根际的4株优良PGPR菌株间的拮抗反应、单独和混合培养菌株的溶磷和分泌植物生长素(IAA)能力、培养液pH值和有机酸总量变化及其彼此之间的相关性。结果表明,各菌株间无拮抗反应,可以混合使用。无机磷培养液中,菌株Hsg+lhs11组合处理有效磷增量(536.2 mg/L)最大,Hsg+ls1-3+lhs11组合次之(475.6 mg/L)。Hsg+lhs11组合菌株处理有效磷增量呈现“1+1>2”的加成效应,Hsg+ls1-3+lhs11处理有效磷增量较单菌株处理时显著提高(P<0.01),但未表现“1+1+1>3”的溶磷效果。有机磷培养液中,lhs11处理有效磷增量(11.11 mg/L)最大,Hsg+ls1-3+lhs11组合次之(9.20 mg/L),Hsg+ls1-3+lhs11组合有效磷增量显著高于其他组合处理。各处理菌株培养液有效磷增量与pH值、有效磷增量与总有机酸量、pH值和总有机酸量之间存在线性相关。单菌株及菌株组合均具有分泌IAA的能力,分泌量在0.212~9.331 μg/mL,Hsg+lhs11组合菌株培养液IAA含量显著高于单菌株Hsg和lhs11(P<0.01),并呈现“1+1>2”的加成效果。综合各处理的促生特性,组合Hsg+lhs11和Hsg+ls1-3+lhs11菌株间互作效应较强,有望成为研制复合菌肥的最佳菌株组合。     

耐镉根际促生菌的筛选及其对一年生黑麦草镉吸收积累的影响

利用含不同镉(Cd)浓度的LB(Luria-Bertani)培养基,从植物根际土壤分离得到32株耐镉根际菌,测定了这些菌株产吲哚乙酸、ACC脱氨酶活性、溶磷能力并根据培养皿促生试验的复筛结果,选取A02,Oj06和Ps08作为供试菌株。以一年生黑麦草(Lolium multiflorum Lam.)为材料,开展了耐镉根际促生菌调控镉胁迫下幼苗生长的试验。当土壤中镉含量为20±0.33mg·kg-1时,分别接种A02,Oj06和Ps08菌株,结果表明:与未接种菌株相比,接种3种菌株后一年生黑麦草地上部生物量和镉积累量皆显著提高,叶片中膜脂过氧化水平(MDA含量)则显著降低(P0.05),土壤镉有效态含量增加,其中A02处理达显著水平(P0.05)。因此,接种耐镉根际促生菌株可显著促进镉胁迫下一年生黑麦草幼苗生长,并且能通过增加土壤中镉的有效态,促进植株对镉的吸收与积累。     

酸奶中乳酸杆菌分离鉴定及其与女性生殖道感染有关的生理生化特性研究

对国内外市售酸奶中添加的乳酸杆菌益生菌进行分离鉴定,对其产H2O2量及与宫颈癌HeLa细胞黏附能力进行分析,并初步判定酸奶中的乳酸杆菌是否对女性生殖道健康具有潜在的保健作用.实验共分离鉴定出10株乳酸杆菌,其中,嗜酸性乳杆菌5株、干酪乳杆菌1株、瑞士乳杆菌1株、鼠李糖乳杆菌1株、植物乳杆菌1株和德式乳杆菌1株.只有瑞士乳杆菌产H2O2量较高且与HeLa细胞的黏附作用较强,其余乳酸杆菌产H2O2的能力偏低.大部分国内外市售酸奶产品中添加的益生菌不具备抑制女性生殖道感染有关的生理生化特性,只有瑞士乳杆菌可能对女性生殖系统的健康具有保护作用.