Helicobacter pylori shows a highly diverse nature in all aspects, from gene profiles to biological features. between H. pylori and host cells is also complex. These characteristics of H. pylori may explain some conflicting results regarding the pathogenicity of H. pylori in human diseases. Not all strains are pathogenic, as exemplified by Type I and Type II strains. This may possibly lead to the development of a live vaccine using non-toxic strains against toxic strains. To achieve this goal, further study is necessary to elucidate the exact role of H. pylori in gastroduodenal diseases.
The whole cells (WC) of three strains of bifidobacteria, Bifidobacterium adolescentis M101-4 (M101-4), B. pseudocatenulatum MBL8320 (MBL8320) and B. catenulatum MBL8318, were transformed into water-soluble and insoluble fractions (SF and IF, respectively) having mitogenic activity in murine splenocytes assay in vitro. A soluble high-molecular weight fraction (SHF) with mitogenic activity was successfully isolated from the SF by the following 6-step procedure: proteinase K treatment, ultrafiltration through a 50 kDa cut-off membrane filter, anion-exchange chromatography, dialysis, ultrafiltration through a 6 kDa cut-off membrane filter, and gel-filtration chromatography. The SHF obtained from the three strains were found to consist of polysaccharides containing -4Gal p 1-(and/or -5Gal f 1-) and -6Glc p 1- as the major residues, and Gal f 1- and -6Gal f 1- as characteristic galactofuranosyl residues by their analytical data. β- Glucosidase digestion of the high-molecular weight fractions after proteinase K treatment led to a decrease in the mitogenic activity for splenocytes, suggesting that β-glucosyl residue in the polysaccharides may play an important role in immunopotentiating activity.
Bifidobacteria showed better adherence to monolayer Ht-29 colonic cancer cells as compared with Lactobacillus acidophilus. Among bifidobacteria, Bifidobacterium infantis 1912 and B. longum 1941 showed highest level of adherence. Among L. acidophilus, strains 2400 and 2415 showed best adherence. Thus, in general, bifidobacteria may be preferred as dietary adjuncts over L. acidophilus. Proteins were found to be present in spent broth of all strains of adhering bacteria involved in adherence of probiotic bacteria to Ht-29 cells. However, involvement of polysaccharides from bacteria and Ht-29 cells for adherence varied from strain to strain of probiotic bacteria. Polysaccharides produced by Ht-29 cell surfaces contributed to adherence than those originating from the bacterial cells. For B. infantis 1912 and B. longum 1941, polysaccharides of both bacterial and Ht-29 origin were involved in adherence. The molecular size of proteins involved in adherence varied among the strains of probiotic bacteria. In B. longum 1941 and B. infantis 1912, a molecular size fraction of 30, 000-50, 000 kDa was responsible for adherence. Adherence was mediated by a bridging structure (possibly a protein-polysaccharide structure) formed between bacterial and Ht-29 cells.
Sorivudine (1-β-D-arabinofuranosyl-5-(E-2-bromovinyl) uracil) is a potent and selective antiviral agent against herpes simplex virus type 1 and varicella-zoster virus. Severe side effects (bone marrow suppression), however, occurred when sorivudine was co-administered with fluorouracil (5-FU)-related anticancer drugs. We have examized the mechanism of the lethal toxicity exerted by the combination treatment. The administration of sorivudine or its major metabolite, 5-(E-2-bromovinyl) uracil (BVU), 1 hr previous to the administration of 5-FU in mice increased the plasma half-life of 5-FU and its area under the curve dramatically. The combination of sorivudine (100 mg/kg) or BVU (20 mg/kg) with sublethal doses of 5-FU (not more than 160 mg/kg) or tegafur (500 mg/kg) induced a lethal endogenous infection of Escherichia coli in all the mice treated, while a single dose of sorivudine, BVU, 5-FU or tegafur did not cause any infection. Streptomycin sulfate protected mice from the lethal toxicity of the drug combinations, suggesting that the toxicity is due to bacterial infection. A parenteral administration of a heat-killed preparation of Lactobacillus casei YIT 9018 (LC 9018) effectively prevented the lethal endogenous infection and escalated the recovery from the chemotherapyinduced hematopoietic injury, suggesting that nonspecific immunopotentiation is also important in preventing the severe side effects of sorivudine in combination with 5-FU-related anticancer drugs.
Deaths and growth depression inevitably occur when newly hatched chickens or turkeys are exposed to microbiological and/or environmental stressors. This phenomenon, termed avian growth depression (AGD), is cited as the costliest disease affecting the poultry industry. The studies presented in this report were undertaken to determine if this disease could be induced in turkey poults under controlled laboratory conditions, and if so, could its mortality and morbidity consequences be prevented or moderated by probiotic treatment with a turkey-specific strain of Lactobacillus reuteri. Evidence is presented showing that both objectives were realized. AGD could be induced by subjecting newly hatched birds to a mild intermittant cooling during their first 48 hr posthatch, and early probiotic intervention resulted in colonization of the gastrointestinal tract with L. reuteri accompanied by significant moderation of the disease.
Avian growth depression (AGD) has been cited as the costliest disease affecting the poultry industry. It occurs when young chickens or turkeys are exposed to nutritional, environmental, and/or microbiological stressors. In this report we describe model systems developed to study AGD in chickens under controlled laboratory conditions. Mild intermittent cooling during the first 48 hr posthatch, peroral Salmonella challenges during the first few days posthatch, and feeding newly-hatched chicks a protein deficient diet were shown to induce AGD. We had previously shown that AGD induced by intermittant cooling of newly hatched poults could be moderated by probiotic administrations of Lactobacillus reuteri. In the present report, evidence is presented showing that moderation of this disease by L. reuteri treatments occurs in chickens as well, and that this probiotic protection occurs whether the disease is induced by an environmental, microbiological, or nutritional stressor.
Turkeys hatched and brooded under commercial conditions exhibit performance losses caused by avian growth depression (AGD). Previous studies carried out under controlled laboratory conditions showed that these losses could be moderated significantly by early probiotic intervention with viable, host-specific strains of Lactobacillus reuteri. Evidence is presented in this report showing that these L. reuteri treatments are effective under field conditions encountered during commercial poultry production. Beneficial effects of L. reuteri probiosis were observed soon after placement of poults and resulted in an overall improved flock performance at market-age as indicated by significantly improved livability, feed conversion, body weight, and Grade A quality carcasses.
Human Lactobacillus strain GG (ATCC 53103) as part of the dietary therapy has been shown to shorten the duration of acute rotavirus diarrhea and to potentiate the intestinal immune response against the virus. We studied the ability of Lactobacillus GG to survive passage through the gut during rotavirus diarrhea in 29 infants, age range 5.4 to 27.5 months. After oral rehydration, they randomly received either a Lactobacillus GG formula or their normal milk ad libitum. All patients who received Lactobacillus GG became colonized with the strain as measured by fecal Lactobacillus GG counts. This result suggests that Lactobacillus GG may promote the establishment of normal intestinal microflora, even during acute gastroenteritis.