Lactobacillus fermentum BR11, a potential new probiotic, alleviates symptoms of colitis induced by dextran sulfate sodium (DSS) in rats

Current treatments for inflammatory bowel disease (IBD) are relatively ineffective. Recently, probiotics have emerged as a potential treatment modality for numerous gastrointestinal disorders, including IBD. Few probiotics, however, have undergone appropriate preclinical screening in vivo. The current study compared the effects of four candidate probiotics on development of dextran sulfate sodium (DSS)-induced colitis in rats. Sprague Dawley rats were gavaged 1 mL of the potential probiotic (1 x 10(10) CFU/mL), or vehicle, twice daily for 14 days. Strains tested were Lactobacillus rhamnosus GG (LGG), Streptococcus thermophilus TH-4 (TH-4), Bifidobacterium lactis Bb12 (Bb12) and Lactobacillus fermentum BR11 (BR11). Colitis was induced from day 7 to 14 via administration of 2% DSS in drinking water. Disease activity index (DAI) was monitored daily until rats were killed at day 14. DAI decreased in DSS+Bb12 and DSS+BR11 compared to DSS+Vehicle. Colon length increased in DSS+BR11 (10%) and DSS+LGG (10%) compared to DSS+Vehicle. DSS+Bb12 and DSS+BR11 prevented the distal colon crypt hyperplasia evident in DSS+Vehicle, DSS+LGG and DSS+TH-4. BR11 was most effective at reducing colitic symptoms. Bb12 had minimal effects, whilst TH-4 did not prevent DSS-colitis and LGG actually exacerbated some indicators of colitis. Further studies into the potential benefits of L. fermentum BR11 are indicated.     

Potential probiotic lactic acid bacteria Lactobacillus rhamnosus (HN001), Lactobacillus acidophilus (HN017) and Bifidobacterium lactis (HN019) do not degrade gastric mucin in vitro

The mucus layer (mucin) coating the surface of the gastrointestinal tract (GIT) plays an important role in the mucosal barrier system. Any damage or disturbance of this mucin layer will compromise the host's mucosal defence function. In the present study, the ability of three potential probiotic lactic acid bacteria (LAB) strains (Lactobacillus rhamnosus HN001, Lactobacillus acidophilus HN017, Bifidobacterium lactis HN019) to degrade mucin in vitro was evaluated, in order to assess their potential pathogenicity and local toxicity. The LAB strains were incubated in medium containing hog gastric mucin (HGM, 0.3%) at 37 degrees C for 48 h, following which any decrease in carbohydrate and protein concentration in the ethanol-precipitated portion of the culture medium was determined, using phenol-sulphuric acid and bicinchonic acid (BCA) protein assays, respectively. The change in molecular weight of mucin glycoproteins, following incubation with the test strains, was monitored by SDS-polyacrylamide gel electrophoresis (SDS-PAGE). In order to expose any ability of the test strains to degrade mucin visually and more directly, the test strains were also cultured on agarose containing 0.3% HGM and incubated anaerobically for 72 h at 37 degrees C. No significant change in the carbohydrate or protein concentration in mucin substrates was found following incubation with the test strains. No mucin fragments were derived from the mucin suspension incubated with test strains, and no mucinolysis zone was identified on agarose. These results demonstrate that the potential probiotic LAB strains tested here were unable to degrade gastrointestinal mucin in vitro, which suggests that these novel probiotic candidates are likely to be non-invasive and non-toxic at the mucosal interface.     

Protective role of Lactobacillus fermentum R6 against Clostridium perfringens in vitro and in chicken breast meat under temperature abuse conditions

Six bacterial species were evaluated to determine their inhibitory effects on Clostridium perfringens in vitro (brain heart infusion broth) and in situ (chicken breast meat) under temperature abuse conditions (4 ± 1 °C for 12 h, followed by 7 h at 28 ± 1 °C and then 4 ± 1 °C for 53 h). During abusive storage, rapid growth of C. perfringens from vegetative cell and spore inocula was observed, exhibiting a 2.68–3.37 log CFU/mL (or g) increase in bacterial counts. In the presence of Pediococcus pentosaceus P1 or Lactobacillus fermentum R6, the counts of C. perfringens remained unchanged in the samples containing vegetative cells at the end of storage (P < 0.05); for those containing spores, the germination and outgrowth were also effectively inhibited, decreasing in bacterial counts of > 1.9 log CFU/mL (or g) compared to those of the control (P < 0.05). The pH of chicken meat was slightly declined by 0.09 in the presence of L. fermentum (P > 0.05), and the inhibitory effect against C. perfringens was ascribed to non-acid antimicrobial substances. These results indicate a potential solution for bio-protecting chicken meat from C. perfringens growth.Industrial relevanceClostridium perfringens is a common pathogen that contaminates meat and meat products, but the organism cannot multiply under cold chain conditions at 4 °C. However, it was reported that temperature abuses commonly occurred during the transportation, storage or retail display of the food chill chain. During the abusive storage, C. perfringens could grow rapidly, which may lead to food poisoning. It is a serious problem for food safety.In this study, Lactobacillus fermentum R6 was found to show effective inhibition on both the growth of C. perfringens vegetative cells and the germination and outgrowth of its spores in chicken meat (P < 0.05) under temperature abuse conditions, and also it had a minimal effect on the pH of the meat (P > 0.05). The results reveal a potential technology for bio-protecting chicken meat from C. perfringens growth.     

Viability of probiotic micro-organisms (Lactobacillus acidophilus La-5 and Bifidobacterium animalis subsp. lactis Bb-12) in ice cream

The purpose of this research was to determine the survival of two probiotic micro-organisms in ice creams (4% fat). The micro-organisms were Lactobacillus acidophilus La-5 and Bifidobacterium animalis subsp . lactis Bb-12 . To meet this objective, an ice cream mixture was formulated and subjected to three treatments. Treatment 1 was inoculated with L. acidophilus , treatment 2 with B. lactis and the third treatment was inoculated with a mixture of both bacteria inoculated in 1 : 1 proportions. The inoculation was with 4% culture for each treatment. The final products were stored at −25°C for 60 days. The ice cream inoculated with L. acidophilus had a final concentration of 2 × 10 ⁶ cfu/g and the survival rate was 87%. The treatment inoculated with B. lactis had a final concentration of 9 × 10 ⁶ cfu/g, with a logarithmic decrease of 10%. When both micro-organisms were inoculated together, the survival rate was 86%.     

Effect of camel milk protein hydrolysates against hyperglycemia,hyperlipidemia, and associated oxidative stress in streptozotocin (STZ)-induced diabetic rats

This study investigated the effect of camel milk protein hydrolysates (CMPH) at 100, 500 and 1,000 mg/kg of body weight (BW) for 8 wk on hyperglycemia, hyperlipidemia, and associated oxidative stress in streptozotocin-induced diabetic rats. Body weights and fasting blood glucose levels were observed after every week until 8 wk, and oral glucose tolerance test (OGTT) levels and biochemical parameters were evaluated after 8 wk in blood and serum samples. Antioxidant enzyme activity and lipid peroxidation in the liver were estimated, and histological examination of the liver and pancreatic tissues was also conducted. Results showed that CMPH at 500 mg/kg of BW [camel milk protein hydrolysate, mid-level dosage (CMPH-M)] exhibited potent hypoglycemic activity, as shown in the reduction in fasting blood glucose and OGTT levels. The hypolipidemic effect of CMPH was indicated by normalization of serum lipid levels. Significant improvement in activity of superoxide dismutase and catalase, and reduced glutathione levels were observed, along with the attenuation of malondialdehyde content in groups fed CMPH, especially CMPH-M, was observed. Decreased levels of liver function enzymes (aspartate aminotransferase and alanine aminotransferase) in the CMPH-M group was also noted. Histology of liver and pancreatic tissue displayed absence of lipid accumulation in hepatocytes and preservation of β-cells in the CMPH-M group compared with the diabetic control group. This is the first study to report anti-hyperglycemic and anti-hyperlipidemic effect of CMPH in an animal model system. This study indicates that CMPH can be suggested for its therapeutic benefits for hyperglycemia and hyperlipidemia, thus validating its use for better management of diabetes and associated comorbidities.     

香菇多糖对烟草灰霉病的防治效果研究

为挖掘香菇多糖( Lentinus,LTN)对常见植物病原菌的防治效果,采用生长速率法和菌丝块接种法检测了香菇多糖对常见植物病原真菌菌丝生长、孢子萌发、种子萌发和烟苗生长的影响及对烟草灰霉病( Tobacco grey mould)的温室防治效果.结果表明:香菇多糖对7种常见植物病原真菌均具有较好的抑制作用,其中1％香菇多糖对烟草灰霉病原菌的抑制活性最高,抑菌圈直径达39.45 mm.香菇多糖能致使烟草灰霉病原菌菌丝分支增多,膨大畸形等异常生长现象,孢子萌发抑制率高达97.63％,孢子致畸率为53.68％.且香菇多糖对烟草种子萌发有较明显的促生作用.盆栽试验表明1％香菇多糖溶液对烟草灰霉病的防治效果达85.05％.     

Effects of gastrointestinal digestion models in vitro on phenolic compounds and antioxidant activity of juçara (Euterpe edulis)

This study evaluated the effects of different gastrointestinal digestion models in vitro on the bioaccessibility of phenolics and antioxidant activity in juçara frozen pulp. In the sequence, method 3 was applied to juçara fruit in three different stages of maturation (vitrin – reddish fruits, mature – purple fruits, tuíra – deep purple fruits). In the method applied, the final pH adopted was 5.0, in order to avoid interference in the assay used to determine the antioxidant activity, and BHT was used to prevent excessive oxidation in the system. In this method, higher values for antioxidant activity were obtained (3574.95–3719.10 μmol L^?1 Trolox 100 g^?1 pulp) compared with the other two methods tested (1969.14–3034.74 μmol L^?1 Trolox 100 g^?1 pulp). In relation to juçara fruit, the mature stage was found to be ideal for processing, showing generally higher values of the bioaccessibility for phenolics and antioxidant activity compared to other maturation stages.     

In vitro ruminal biohydrogenation of eicosapentaenoic (EPA), docosapentaenoic (DPA), and docosahexaenoic acid (DHA) in cows and ewes: Intermediate metabolites and pathways

A great deal of uncertainty still exists about intermediate metabolites and pathways explaining the biohydrogenation (BH) of 20- and 22-carbon polyunsaturated fatty acids (PUFA). Therefore, this study was conducted to provide further insight into the ruminal metabolism of 20:5 n-3 (EPA), 22:5 n-3 (DPA), and 22:6 n-3 (DHA), the main n-3 PUFA present in the marine lipids used in dairy ruminant feeding, and to examine potential differences between bovine and ovine. To meet this aim, we investigated the 20- and 22-carbon metabolites accumulated during in vitro incubation of EPA, DPA, and DHA with rumen inocula from cows and ewes. The PUFA were added at a dose of 2% incubated dry matter and digesta samples were analyzed after 24 h of incubation using complementary gas-liquid chromatography of fatty acid methyl esters and gas chromatography-mass spectrometry of 4,4-dimethyloxazoline derivatives. Results suggested that the main BH pathway of EPA and DPA would proceed via the reduction of the double bond closest to the carboxyl group (cis-5 in EPA and cis-7 in DPA); curiously, this mechanism seemed of much lower importance for DHA. Thus, DPA would not be a major intermediate product of DHA and their BH might actually follow separate pathways, with the accumulation of numerous unique metabolites in each case. A principal component analysis supported this hypothesis, with a clear separation between PUFA treatments in the score and loading plots. Within EPA and DPA groups, cow and ewe samples loaded separately from each other but not distant. No conjugated 20:5, 22:5, or 22:6 isomer compatible with the initial product of EPA, DPA, or DHA metabolism, respectively, was identified in the ruminal digesta, although this would not unequivocally exclude their transient formation. In this regard, results from DPA incubations provided the first indication that the metabolism of this very long chain PUFA may involve the formation of conjugated double bond structures. The BH of EPA, DPA, and DHA resulted in the appearance of several tentative trans-10–containing metabolites, showing a general trend to be more abundant in the digesta of ewes than in that of cows. This finding was speculated to have some relationship with the susceptibility of dairy sheep to marine lipid-induced milk fat depression. Differences in the relative proportion of intermediate products would also suggest an influence of ruminant species on BH kinetics, with a process that would likely be slower and less complete in cows than in ewes.     

Influence of cholera toxin (an adenylate cyclase activator) on deoxyribonucleic acid synthesis of bovine mammary tissue in vitro and in athymic nude mice

Bovine mammary tissue from midpregnant heifers was placed in explant culture to which chlorea toxin (a potent adenylate cyclase activator) was added (0 to 100 ng/ml). Chlorea toxin increased incorporation of thymidine into DNA in the cultures; response was maximum with 10 ng/ml chlorea toxin and approximately 24 h after addition of cholera toxin. In other studies, bovine mammary tissue was transplanted subcutaneously to ovariectomized athymic nude mice. Subsequent treatment of the mice with cholera toxin alone did not affect growth of bovine mammary tissue. However, treatment with estradiol plus progesterone increased DNA synthesis in epithelial cells. In estradiol plus progesterone-treated mice, cholera toxin injections further increased DNA synthesis. In addition, estradiol plus progesterone treatment in vivo (in athymic nude mice) increased DNA synthesis of bovine mammary tissue in response to cholera toxin in vitro. This synergism between cholera toxin and ovarian steroids may have been mediated, at least in part, by estradiol plus progesterone induction of cyclic AMP dependent protein kinase, as the activity of this enzyme was increased by estradiol plus progesterone.     

Studies on antioxidant activities of mucuna seed (Mucuna pruriens var utilis) extract and various non‐protein amino/imino acids through in vitro models

The antioxidant activities of a methanolic extract of mucuna beans (Mucuna pruriens var utilis) and several non‐protein amino/imino acids, namely L ‐3,4‐dihydroxyphenylalanine (L ‐dopa), L ‐3‐carboxy‐6,7‐dihydroxy‐1,2,3,4‐tetrahydroisoquinoline (compound I), (?)‐1‐methyl‐3‐carboxy‐6,7‐dihydroxy‐1,2,3,4‐tetrahydroisoquinoline (compound II) and 5‐hydroxytryptophan (5‐HTP), were evaluated. By virtue of their hydrogen‐donating ability, all the tested compounds and the mucuna seed extract showed excellent reducing power, with the highest values being recorded for L ‐dopa in a dose‐dependent manner. Similarly, as compared with synthetic antioxidants (BHT and BHA) and quercetin, all the tested compounds and the seed extract were found to be more potent in free radical‐scavenging activity (P < 0.05) against α,α‐diphenyl‐β‐picrylhydrazyl (DPPH^?) radicals. Hydroxyl radicals (OH^?) and superoxide anion radicals (O₂^??) were effectively scavenged by the tested compounds, with the exception that no scavenging activity of 5‐HTP was observed on (O₂^??) up to a concentration of 2 mg ml^?1, as was also the case for BHA. Among the tested non‐protein amino/imino acids and seed extract the highest peroxidation‐inhibiting activity (95%) was recorded for 5‐HTP. On the other hand, in the linoleic acid/β‐carotene‐bleaching system, L ‐dopa, compound I and compound II acted as pro‐oxidants, whereas the seed extract showed only weak antioxidant activity as in the linoleic acid emulsion system. Copyright © 2003 Society of Chemical Industry