Separation of the Two Constituent Polypeptide Chains of Ricin D

Two constituent polypeptide chains were isolated from performic acid-oxidized ricin D by DEAE-cellulose column chromatography in phosphate buffer, pH 7.0, containing 8m urea or from reduced-carboxymethylated ricin D by gel filtration on Sephadex G-75 followed by DEAE- cellulose column chromatography in Tris-HCl buffer, pH 8.5. Amino acid analyses of the isolated two chains revealed that they were distinct molecules possessing similar molecular weights of near 30,000 and linked by one disulfide bond in ricin D.     

双歧杆菌质粒聚合酶基因表达系统的构建及其鉴定

目的构建可以在双歧杆菌表达外源性基因的系统。方法PCR扩增双歧杆菌质粒聚合酶基因（BPP）并连接至质粒pBS—T以形成重组质粒pBS—BPP。PCR扩增双歧杆菌内源性阿拉伯糖苷酶的启动子及分泌性信号肽DNA序列（ara）并连接至质粒pBAD—A以形成重组质粒pBAD—ara,然后将增强绿色荧光蛋白（eGFP）基因连接至质粒pBAD—ara以形成重组质粒pBAD—ara—GFP。采用基因重组技术重组含有ara、BPP、eGFP基因序列并可将外源性基因分泌表达于菌体外及锚定表达于细胞壁的质粒pBS—BPP—ara—GFP,激光共聚焦显微镜下观察含有pBS—BPP—ara—GFP质粒及对照质粒的E．coli,验证eGFP定位表达情况。结果所构建的表达系统可以在E．coli中表达eGFP基因。结论通过基因重组方法成功构建了双歧杆菌表达系统,其可将外源基因分泌表达于菌体外。     

益气健脾中药颗粒剂对早期断奶仔猪肠道菌群的影响

目的研究中药复方颗粒剂对断奶仔猪肠道微生态的影响。方法实验选用人工感染大肠埃希菌引起腹泻的28日龄断奶仔猪54头,随机平均分为3组,每组3个重复,Ⅰ组抗生素治疗组、Ⅱ组中药复方颗粒剂治疗组、Ⅲ组不用任何药物治疗的空白对照组。分别于用药后第14天时,每组随机抽取1头屠宰,无菌采集空肠,回肠和盲肠内容物,利用平板计数法测定各肠段大肠埃希菌、双歧杆菌和乳酸杆菌数量。结果 Ⅰ组双歧杆菌、乳酸杆菌及大肠埃希菌的数量均显著小于Ⅲ组（P〈0.05）;Ⅱ组双歧杆菌和乳酸杆菌的数量显著大于Ⅲ组（P〈0.05）,大肠埃希菌数量显著小于Ⅲ组（P〈0.05）; n组双歧杆菌和乳酸杆菌的数量极显著大于Ⅰ组（P〈0.01）,Ⅱ组与Ⅰ组大肠埃希菌数量差异无统计学意义（P〉0.05）。结论该中药复方颗粒剂具有显著增加断奶仔猪肠道中双歧杆菌和乳酸杆菌的数量,降低大肠埃希菌数量,减少腹泻频率的作用。     

双歧杆菌乳杆菌三联活菌片联合血必净注射液对急性胰腺炎患者炎性介质、细胞免疫指标及肠黏膜屏障功能的影响

目的:探讨血必净注射液联合双歧杆菌乳杆菌三联活菌片治疗急性胰腺炎(SAP)患者的临床疗效。方法:选取2016年9月～2019年4月期间我院收治的SAP患者119例,根据随机数字表法将患者随机分为对照组(n=59)和研究组(n=60),对照组给予血必净注射液治疗,研究组在对照组的基础上联合双歧杆菌乳杆菌三联活菌片治疗,比较两组临床疗效,炎性介质、细胞免疫指标水平、肠黏膜屏障功能及不良反应发生情况。结果:研究组治疗7d后总有效率高于对照组(P0.05)。两组治疗期间未见药品不良反应发生。两组血清内毒素、二胺氧化酶(DAO)、白介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)以及C反应蛋白(CRP)、CD8~+水平均降低,且研究组低于对照组(P0.05),CD4~+/CD8~+、CD4~+、NK细胞水平升高,且研究组高于对照组(P0.05)。结论:SAP患者在血必净的基础上联合双歧杆菌乳杆菌三联活菌片治疗,可提高机体细胞免疫功能,改善炎性因子水平和肠黏膜屏障功能,且用药安全性较好,临床应用价值较高。     

In vitro measurement of the impact of human milk oligosaccharides on the faecal microbiota of weaned formula-fed infants compared to a mixture of prebiotic fructooligosaccharides and galactooligosaccharides

Aims: To investigate the impact of human milk oligosaccharides (HMOs) from a single donor (SO), HMOs from multiple donors (PO), a fructooligosaccharides and galactooligosaccharides mixture (FG) on the composition of a batch culture inoculated with faecal microbiota from formula‐fed infants. Methods and Results: Three substrates were compared using 24‐h pH‐controlled anaerobic batch cultures inoculated with infant faecal slurries. Changes in bacterial populations, short‐chain fatty acids (SCFA) production and bacterial 16S rRNA gene profiles were determined. All three substrates significantly increased numbers of bifidobacteria, bacteroides and those aligning with the clostridial cluster XIVa. Neither the FG nor the HMOs substrates supported the growth of the Clostridium perfringens–histolyticum group. SCFA production corresponded to changes observed in bacterial populations. Denaturing gradient gel electrophoresis fingerprint analysis showed a distinct profile of faecal bacteria present in each infant. Conclusions: HMOs modulated infant faecal culture composition in a similar manner to the prebiotic mixture FG in vitro. Significance and Impact of the Study: This is the first demonstration of the impact of pure HMOs on the mixed culture of infant faecal bacteria. HMOs induced the growth of several saccharolytic bacterial groups and may thus play a role in the health‐promoting attributes of human breast milk and have an extended significance in infant diet during/after weaning.     

Functional analysis of the pBC1 replicon from <Emphasis Type="Italic">Bifidobacterium catenulatum</Emphasis> L48

To determine the minimal replicon of pBC1 (a 2.5-kb cryptic plasmid of Bifidobacterium catenulatum L48) and to check the functionality of its identified open reading frames (ORFs) and surrounding sequences, different segments of pBC1 were amplified by polymerase chain reaction (PCR) and cloned into pBif, a replication probe vector for bifidobacteria. The largest fragment tested in this manner encompassed most of the pBC1 sequence, while the shortest just included the repB gene and its immediate upstream sequences. Derivatives were all shown to allow replication in bifidobacteria. Surprisingly, both the transformation frequency and segregational stability in the absence of antibiotic selection decreased with reducing plasmid length. The relative copy number of the constructs (ranging from around 3 to 23 copies per chromosome equivalent, as compared to 30 copies for the original pBC1) was shown to be strain dependent and to decrease with reducing plasmid length. These results suggest that, although not essential, the copG-like and orfX-like genes of pBC1 play important roles in pBC1 replication. Interruption of repB produced a construct incapable of replicating in bifidobacteria. The analysis of pBC1 will allow its use in the construction of general and specific cloning vectors.     

纳米中药龙胆草复方制剂对实验性大鼠癫痫的防治作用

目的观察纳米中药龙胆草复方制剂扶植肠道双歧杆菌对实验性大鼠癫痫的治疗作用。方法实验以大鼠腹腔注射青霉素600万U/kg制成癫痫模型。应用纳米治疗,检测双歧杆菌及脑内r氨-基丁酸含量的变化。结果纳米中药持续7 d治疗后,肠道双歧杆菌菌量明显上升,与自然恢复组比较差异有极显著性(P<0.01)。脑内r氨-基丁酸含量接近正常。结论纳米中药龙胆草复方制剂具有良好的抗癫痫作用。     

Importance of probiotics in the prevention and treatment of colorectal cancer

Colorectal cancer (CRC) remains one of the most common and deadly cancers. Intestinal gut microflora is important to maintain and contributes to several intestinal functions, including the development of the mucosal immune system, absorption of complex macromolecules, synthesis of amino acids/vitamins and the protection against pathogenic microorganisms. It is well known that the gut microbiota changes or dysbiosis may have an essential impact in the initiation and promotion of chronic inflammatory pathways and also have a profound different genetic and epigenetic alterations leading to dysplasia, clonal expansion, and malignant transformation. Probiotic bacteria has antitumor activity with various mechanisms such as nonspecific physiological and immunological mechanisms. This review evaluates the effects of microbiota and probiotics in clinical trials, in vitro and animal model studies that have explored how probiotic against cancer development and also discusses the possible immunomodulatory mechanisms. Several mechanisms alteration of the intestinal microflora; inactivation of cancerogenic compounds; competition with putrefactive and pathogenic microbiota; improvement of the host's immune response; antiproliferative effects via regulation of apoptosis and cell differentiation; fermentation of undigested food; inhibition of tyrosine kinase; reduces the enteropathogenic complications before and after colon cancer surgery and improve diarrhea and it's have been able to create the integrity of gut mucosal and have stimulatory effects on the systemic immune system and prevent the CRC metastasis. Research in clinical trials encouraging findings that support a role of probiotics in CRC prevention and improve the safety and effectiveness of cancer therapy even though additional clinical research is still necessary.     

Comparative genomics of the Bifidobacterium breve taxon

Background

Bifidobacteria are commonly found as part of the microbiota of the gastrointestinal tract (GIT) of a broad range of hosts, where their presence is positively correlated with the host’s health status. In this study, we assessed the genomes of thirteen representatives of Bifidobacterium breve, which is not only a frequently encountered component of the (adult and infant) human gut microbiota, but can also be isolated from human milk and vagina.

Results

In silico analysis of genome sequences from thirteen B. breve strains isolated from different environments (infant and adult faeces, human milk, human vagina) shows that the genetic variability of this species principally consists of hypothetical genes and mobile elements, but, interestingly, also genes correlated with the adaptation to host environment and gut colonization. These latter genes specify the biosynthetic machinery for sortase-dependent pili and exopolysaccharide production, as well as genes that provide protection against invasion of foreign DNA (i.e. CRISPR loci and restriction/modification systems), and genes that encode enzymes responsible for carbohydrate fermentation. Gene-trait matching analysis showed clear correlations between known metabolic capabilities and characterized genes, and it also allowed the identification of a gene cluster involved in the utilization of the alcohol-sugar sorbitol.

Conclusions

Genome analysis of thirteen representatives of the B. breve species revealed that the deduced pan-genome exhibits an essentially close trend. For this reason our analyses suggest that this number of B. breve representatives is sufficient to fully describe the pan-genome of this species. Comparative genomics also facilitated the genetic explanation for differential carbon source utilization phenotypes previously observed in different strains of B. breve.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-170) contains supplementary material, which is available to authorized users.