AIM: To assess whether juvenile chronic ferric iron ingestion limit colitis and dysbiosis at adulthood in rats and mice. METHODS: Two sets of experiments were designed. In the first set, recently weaned mice were eith...AIM: To assess whether juvenile chronic ferric iron ingestion limit colitis and dysbiosis at adulthood in rats and mice. METHODS: Two sets of experiments were designed. In the first set, recently weaned mice were either orally administered ferrous (Fe2+) iron salt or ferric (Fe3+) microencapsulated iron for 6 wk. The last week of experiments trinitrobenzene sulfonic acid (TNBS) colitis was induced. In the second set, juvenile rats received the microencapsulated ferric iron for 6 wk and were also submitted to TNBS colitis during the last week of experiments. In both sets of experiments, animals were sacrificed 7 d after TNBS instillation. Severity of the inflammation was assessed by scoring macroscopic lesions and quantifying colonic myeloperoxidase (MPO) activity. Alteration of the microflora profile was estimated usingquantitative polymerase chain reaction (qPCR) by measuring the evolution of total caecal microflora, Bacteroidetes, Firmicutes and enterobacteria. RESULTS: Neither ferrous nor ferric iron daily exposures at the juvenile period result in any effect in control animals at adulthood although ferrous iron repeated administration in infancy limited weight gain. Ferrous iron was unable to limit the experimental colitis (1.71 ± 0.27 MPO U/mg proteinvs 2.47 ± 0.22 MPO U/mg protein in colitic mice). In contrast, ferric iron significantly prevented the increase of MPO activity (1.64 ± 0.14 MPO U/mg protein) in TNBS-induced colitis. Moreover, this positive effect was observed at both the doses of ferric iron used (75 and 150 mg/kg per day po - 6 wk). In the study we also compared, in both rats and mice, the consequences of chronic repeated low level exposure to ferric iron (75 mg/kg per day po - 6 wk) on TNBS-induced colitis and its related dysbiosis. We confirmed that ferric iron limited the TNBS-induced increase of MPO activity in both the rodent species. Furthermore, we assessed the ferric iron incidence on TNBS-induced intestinal microbiota dysbiosis. At first, we needed to optimize the isolation and quantify DNA copy numbers using standard curves to perform by qPCR this interspecies comparison. Using this approach, we determined that total microflora was similar in control rats and mice and was mainly composed of Firmicutes and Bacteroidetes at a ratio of 10/1. Ferric juvenile administration did not modify the microflora profile in control animals. Total microflora numbers remained unchanged whichever experimental conditions studied. Following TNBS-induced colitis, the Firmicutes/Bacteroidetes ratio was altered resulting in a decrease of the Firmicutes numbers and an increase of the Bacteroidetes numbers typical of a gut inflammatory reaction. In parallel, the subdominant population, the enterobacteria was also increased. However, ferric iron supplementation for the juvenile period prevented the increase of Bacteroidetes and of enterobacteria numbers consecutive to the colitis in both the studied species at adulthood.CONCLUSION: Rats and mice juvenile chronic ferric iron ingestion prevents colitis and dysbiosis at adulthood as assessed by the first interspecies comparison.展开更多
In recent years, research on biopolymer based-coating containing natural antimicrobial agents is developing significantly. The objective of this study was to evaluate the antimicrobial efficiency of six formulations c...In recent years, research on biopolymer based-coating containing natural antimicrobial agents is developing significantly. The objective of this study was to evaluate the antimicrobial efficiency of six formulations containing pre-selected natural antimicrobial compounds against Listeria monocytogenes, Escherichia coli O 157：H7, Salmonella typhimurium, the total bacteria and total yeasts and molds in cauliflower. Each formulation was subjected to a sensory test in parallel to microbiological analysis and the efficiency during storage at 5 ℃ was evaluated for the two best formulations, based on their ability to eliminate the target microorganisms. Both formulations were able to reduce all pathogens and total flora below detectable levels after 24 h of storage at 5 ℃. Using washing or spraying treatments, the two formulations were able to reduce Listeria to undetectable levels for 3 d. This efficiency was extended to 7 d when the formulations were incorporated into an edible coating. Washing treatment with the two formulations was also able to limit the growth of yeast and molds at levels lower than 2 log, for more than 7 d. The population of E. coli was reduced to below the detection limit during 14 d of storage, after washing treatment with the two formulations. The spraying treatment of cauliflower with the formulations allowed the use of very small amounts of antimicrobials while maintaining a fairly good efficiency, greatly reducing the potential costs of implementing this method in the industry. Future research may focus on development of nanoemulsion of antimicrobial formulations based on the developed antimicrobial formulations in this study to improve the better coating efficiency.展开更多
The overall objective of the present study is to evaluate the impact of the heap fermentation of cocoa on microbial dynamics and physicochemical parameters of the soil. The methodology was to heap fermentation broad b...The overall objective of the present study is to evaluate the impact of the heap fermentation of cocoa on microbial dynamics and physicochemical parameters of the soil. The methodology was to heap fermentation broad beans 600 cocoa pods moved to a place after the soil was taken for microbiological and physicochemical analyzes considered the control sample. In addition, cocoa lixiviate and soil were subjected to analyze. Chemical analysis of cocoa lixiviate revealed the absence of heavy metals such as cadmium, chromium. It appears from the analysis of soil than clays represent on average 46.67%, 8.03% for fine silt, heavy silt 5.69%, 15.39% fine sands and heavy sands 20.02%. Microbiological analysis revealed the abundance of total coliform up to 4.6× 103 CFU/g soil. The variations of the abundance of yeasts are 0.01 × 103 CFU/g soil obtained on day 2 at 12 o＇clock to 3.5 × 103 CFU/g soil observed on day 3 to 18 pm （0-3 cm deep）. However, further study on the assessment of biodiversity after the fermentation would determine its species richness.展开更多
Escherichia coli O157：H7 is known to cause food borne illness globally. Treatment of infections caused by this organism is difficult because the administration of antibiotics might precipitate kidney complications; t...Escherichia coli O157：H7 is known to cause food borne illness globally. Treatment of infections caused by this organism is difficult because the administration of antibiotics might precipitate kidney complications; therefore there is the need to search for alternative therapy. In this study, the therapeutic and immunomodulatory effects of raw maize ＂ogi＂ was investigated on rats infected with Escherichia coli 0157：H7. Infected rats treated with maize ＂ogi＂ slurry 1.0 mL once or twice daily and maize ＂ogi＂ liquor, 1.0 mL twice daily recovered 72 h while those that were treated with less than 1.0 mL recovered by 96 h. Without treatment with ＂ogi＂ however, the rats started recovering by 120 h. The treatment caused the white blood cells which had already gone up as a result of the infection to reduce significantly （P 〈 0.05） by 24 h of administration of raw fermented maize ＂ogi＂ components to the infected rats. It also caused a significant decrease in the lymphocyte counts of the infected and treated rats by 24 h. On the other hand, there was an increase in the neutrophil count irrespective of the different volumes and different components of raw ＂ogi＂ used by 24 h but by the 72 h of treatment, it started to decrease and by 120 h reduced to normal levels. Since the administration of raw maize ＂ogi＂ either slurry or liquor caused the duration of infection in rats infected with Escherichia coli 0157：H7 to reduce from 120 h to 72 h, it is therefore suggested that people having diarrhoea caused by this organism could drink fermented raw maize ＂ogi＂ slurry or liquor to treat the infection.展开更多
Sensorial and microbiological characteristics of a Brazilian fresh cheese samples with Bifidobacterium animalis subps. lactis as well as samples with this probiotic and polydextrose, a prebiotic ingredient, were evalu...Sensorial and microbiological characteristics of a Brazilian fresh cheese samples with Bifidobacterium animalis subps. lactis as well as samples with this probiotic and polydextrose, a prebiotic ingredient, were evaluated. The addition of this microorganism was studied as： （1） lyophilized probiotic added to cheese curd and （2） by using milk previously fermented by this probiotic to produce the cheese. Cheese samples were microbiologically characterized after 0, 7, 14, 21 and 28 days of storage at a temperature of 4 ℃. The microbiological analyses conducted were quantification of total lactic acid bacteria, mesophilic microorganisms, Bif. animalis subps, lactis, coliforms at 30 ℃ and 45 ℃. Affective sensory test was conducted for two different cheese samples （with probiotic and with probiotic and prebiotic） as well as for control one week after manufacturing date. Cheese samples provided acceptable results for coliform counts at 30 ℃ and 45 ℃ in compliance with legislation. The cheese samples produced using milk fermented by probiotic showed counts of 107-108 CFU/g after 28 days of storage, which assures functional property for this product to be claimed.展开更多
The strains ofLactobacillus delbrueckii subsp, lactis widely used in food preservation due to ability produce high amount of hydrogen peroxide at refrigerator temperatures to inhibit food-borne pathogens and psychroph...The strains ofLactobacillus delbrueckii subsp, lactis widely used in food preservation due to ability produce high amount of hydrogen peroxide at refrigerator temperatures to inhibit food-borne pathogens and psychrophilic spoilage microorganisms. In order to improve of bio-preservation efficacy ofL. delbrueckii MH 10 mutations causing resistance to streptomycin （str） were used. Among UV-mutagenized population of L. delbruecla＇i three str mutants producing high amounts of H2O2 were selected. Sir mutants produced significant amounts of hydrogen peroxide 50-60 μg/ml in sodium phosphate buffer （0.2 M, pH 6.5） and in beef broth （BB） at 5 ℃ for 5 days submerged cultivation without of growth. Evaluation mutants antibacterialactivity at refrigeration temperatures against food-borne pathogen Escherichia coli O157：H7 revealed elimination of pathogen total number up to practically undetectable amount for 3 days. In case of solid-state cultivation on agar-based medium, disks soaked by mutant cells suspensions formed larger inhibitory zones on E. coli O157：H7 lawn for one-day cold exposition. The size of inhibition zone depends on concentration of LAB cells. Str mutants L. delbrueckii reduced initial amount 2 - 105 of E. coil O 157：H7 in ground beef up to 3 log for 3 days of solid-state cocultivation when the wild strain reduced only 2 log. The application ofL. delbrueckii mutants did not cause any changes in sensory characteristics of ground beef, moreover promotes expanding of shelf-life due to inhibition of psychrophilic spoilage microorganisms.展开更多
We applied a resistance split-fusion strategy to increase the in vivo direct cloning efficiency mediated by Red recombination. The cat cassette was divided into two parts： cma （which has a homologous sequence with ...We applied a resistance split-fusion strategy to increase the in vivo direct cloning efficiency mediated by Red recombination. The cat cassette was divided into two parts： cma （which has a homologous sequence with cmb） and cmb, each of which has no resistance separately unless the two parts are fused together. The crab sequence was integrated into one flank of a target clon- ing region in the chromosome, and a linear vector containing the cma sequence was electroporated into the cells to directly capture the target region. Based on this strategy, we successfully cloned an approximately 48 kb DNA fragment from the E. coli DH1-Z chromosome with a positive frequency of approximately 80%. Combined with double-strand breakage-stimulated homologous recombination, we applied this strategy to successfully replace the corresponding region of the E. coli DH36 chromosome and knock out four non-essential genomic regions in one step. This strategy could provide a powerful tool for the heterologous expression of microbial natural product biosynthetic pathways for genome assembly and for the functional study of DNA sequences dozens of kilobases in length.展开更多
基金Supported by Institut Polytechnique LaSalle Beauvais
文摘AIM: To assess whether juvenile chronic ferric iron ingestion limit colitis and dysbiosis at adulthood in rats and mice. METHODS: Two sets of experiments were designed. In the first set, recently weaned mice were either orally administered ferrous (Fe2+) iron salt or ferric (Fe3+) microencapsulated iron for 6 wk. The last week of experiments trinitrobenzene sulfonic acid (TNBS) colitis was induced. In the second set, juvenile rats received the microencapsulated ferric iron for 6 wk and were also submitted to TNBS colitis during the last week of experiments. In both sets of experiments, animals were sacrificed 7 d after TNBS instillation. Severity of the inflammation was assessed by scoring macroscopic lesions and quantifying colonic myeloperoxidase (MPO) activity. Alteration of the microflora profile was estimated usingquantitative polymerase chain reaction (qPCR) by measuring the evolution of total caecal microflora, Bacteroidetes, Firmicutes and enterobacteria. RESULTS: Neither ferrous nor ferric iron daily exposures at the juvenile period result in any effect in control animals at adulthood although ferrous iron repeated administration in infancy limited weight gain. Ferrous iron was unable to limit the experimental colitis (1.71 ± 0.27 MPO U/mg proteinvs 2.47 ± 0.22 MPO U/mg protein in colitic mice). In contrast, ferric iron significantly prevented the increase of MPO activity (1.64 ± 0.14 MPO U/mg protein) in TNBS-induced colitis. Moreover, this positive effect was observed at both the doses of ferric iron used (75 and 150 mg/kg per day po - 6 wk). In the study we also compared, in both rats and mice, the consequences of chronic repeated low level exposure to ferric iron (75 mg/kg per day po - 6 wk) on TNBS-induced colitis and its related dysbiosis. We confirmed that ferric iron limited the TNBS-induced increase of MPO activity in both the rodent species. Furthermore, we assessed the ferric iron incidence on TNBS-induced intestinal microbiota dysbiosis. At first, we needed to optimize the isolation and quantify DNA copy numbers using standard curves to perform by qPCR this interspecies comparison. Using this approach, we determined that total microflora was similar in control rats and mice and was mainly composed of Firmicutes and Bacteroidetes at a ratio of 10/1. Ferric juvenile administration did not modify the microflora profile in control animals. Total microflora numbers remained unchanged whichever experimental conditions studied. Following TNBS-induced colitis, the Firmicutes/Bacteroidetes ratio was altered resulting in a decrease of the Firmicutes numbers and an increase of the Bacteroidetes numbers typical of a gut inflammatory reaction. In parallel, the subdominant population, the enterobacteria was also increased. However, ferric iron supplementation for the juvenile period prevented the increase of Bacteroidetes and of enterobacteria numbers consecutive to the colitis in both the studied species at adulthood.CONCLUSION: Rats and mice juvenile chronic ferric iron ingestion prevents colitis and dysbiosis at adulthood as assessed by the first interspecies comparison.
文摘In recent years, research on biopolymer based-coating containing natural antimicrobial agents is developing significantly. The objective of this study was to evaluate the antimicrobial efficiency of six formulations containing pre-selected natural antimicrobial compounds against Listeria monocytogenes, Escherichia coli O 157：H7, Salmonella typhimurium, the total bacteria and total yeasts and molds in cauliflower. Each formulation was subjected to a sensory test in parallel to microbiological analysis and the efficiency during storage at 5 ℃ was evaluated for the two best formulations, based on their ability to eliminate the target microorganisms. Both formulations were able to reduce all pathogens and total flora below detectable levels after 24 h of storage at 5 ℃. Using washing or spraying treatments, the two formulations were able to reduce Listeria to undetectable levels for 3 d. This efficiency was extended to 7 d when the formulations were incorporated into an edible coating. Washing treatment with the two formulations was also able to limit the growth of yeast and molds at levels lower than 2 log, for more than 7 d. The population of E. coli was reduced to below the detection limit during 14 d of storage, after washing treatment with the two formulations. The spraying treatment of cauliflower with the formulations allowed the use of very small amounts of antimicrobials while maintaining a fairly good efficiency, greatly reducing the potential costs of implementing this method in the industry. Future research may focus on development of nanoemulsion of antimicrobial formulations based on the developed antimicrobial formulations in this study to improve the better coating efficiency.
文摘The overall objective of the present study is to evaluate the impact of the heap fermentation of cocoa on microbial dynamics and physicochemical parameters of the soil. The methodology was to heap fermentation broad beans 600 cocoa pods moved to a place after the soil was taken for microbiological and physicochemical analyzes considered the control sample. In addition, cocoa lixiviate and soil were subjected to analyze. Chemical analysis of cocoa lixiviate revealed the absence of heavy metals such as cadmium, chromium. It appears from the analysis of soil than clays represent on average 46.67%, 8.03% for fine silt, heavy silt 5.69%, 15.39% fine sands and heavy sands 20.02%. Microbiological analysis revealed the abundance of total coliform up to 4.6× 103 CFU/g soil. The variations of the abundance of yeasts are 0.01 × 103 CFU/g soil obtained on day 2 at 12 o＇clock to 3.5 × 103 CFU/g soil observed on day 3 to 18 pm （0-3 cm deep）. However, further study on the assessment of biodiversity after the fermentation would determine its species richness.
文摘Escherichia coli O157：H7 is known to cause food borne illness globally. Treatment of infections caused by this organism is difficult because the administration of antibiotics might precipitate kidney complications; therefore there is the need to search for alternative therapy. In this study, the therapeutic and immunomodulatory effects of raw maize ＂ogi＂ was investigated on rats infected with Escherichia coli 0157：H7. Infected rats treated with maize ＂ogi＂ slurry 1.0 mL once or twice daily and maize ＂ogi＂ liquor, 1.0 mL twice daily recovered 72 h while those that were treated with less than 1.0 mL recovered by 96 h. Without treatment with ＂ogi＂ however, the rats started recovering by 120 h. The treatment caused the white blood cells which had already gone up as a result of the infection to reduce significantly （P 〈 0.05） by 24 h of administration of raw fermented maize ＂ogi＂ components to the infected rats. It also caused a significant decrease in the lymphocyte counts of the infected and treated rats by 24 h. On the other hand, there was an increase in the neutrophil count irrespective of the different volumes and different components of raw ＂ogi＂ used by 24 h but by the 72 h of treatment, it started to decrease and by 120 h reduced to normal levels. Since the administration of raw maize ＂ogi＂ either slurry or liquor caused the duration of infection in rats infected with Escherichia coli 0157：H7 to reduce from 120 h to 72 h, it is therefore suggested that people having diarrhoea caused by this organism could drink fermented raw maize ＂ogi＂ slurry or liquor to treat the infection.
文摘Sensorial and microbiological characteristics of a Brazilian fresh cheese samples with Bifidobacterium animalis subps. lactis as well as samples with this probiotic and polydextrose, a prebiotic ingredient, were evaluated. The addition of this microorganism was studied as： （1） lyophilized probiotic added to cheese curd and （2） by using milk previously fermented by this probiotic to produce the cheese. Cheese samples were microbiologically characterized after 0, 7, 14, 21 and 28 days of storage at a temperature of 4 ℃. The microbiological analyses conducted were quantification of total lactic acid bacteria, mesophilic microorganisms, Bif. animalis subps, lactis, coliforms at 30 ℃ and 45 ℃. Affective sensory test was conducted for two different cheese samples （with probiotic and with probiotic and prebiotic） as well as for control one week after manufacturing date. Cheese samples provided acceptable results for coliform counts at 30 ℃ and 45 ℃ in compliance with legislation. The cheese samples produced using milk fermented by probiotic showed counts of 107-108 CFU/g after 28 days of storage, which assures functional property for this product to be claimed.
文摘The strains ofLactobacillus delbrueckii subsp, lactis widely used in food preservation due to ability produce high amount of hydrogen peroxide at refrigerator temperatures to inhibit food-borne pathogens and psychrophilic spoilage microorganisms. In order to improve of bio-preservation efficacy ofL. delbrueckii MH 10 mutations causing resistance to streptomycin （str） were used. Among UV-mutagenized population of L. delbruecla＇i three str mutants producing high amounts of H2O2 were selected. Sir mutants produced significant amounts of hydrogen peroxide 50-60 μg/ml in sodium phosphate buffer （0.2 M, pH 6.5） and in beef broth （BB） at 5 ℃ for 5 days submerged cultivation without of growth. Evaluation mutants antibacterialactivity at refrigeration temperatures against food-borne pathogen Escherichia coli O157：H7 revealed elimination of pathogen total number up to practically undetectable amount for 3 days. In case of solid-state cultivation on agar-based medium, disks soaked by mutant cells suspensions formed larger inhibitory zones on E. coli O157：H7 lawn for one-day cold exposition. The size of inhibition zone depends on concentration of LAB cells. Str mutants L. delbrueckii reduced initial amount 2 - 105 of E. coil O 157：H7 in ground beef up to 3 log for 3 days of solid-state cocultivation when the wild strain reduced only 2 log. The application ofL. delbrueckii mutants did not cause any changes in sensory characteristics of ground beef, moreover promotes expanding of shelf-life due to inhibition of psychrophilic spoilage microorganisms.
基金supported by the National Natural Science Foundation of China(81373286)National Basic Research Program of China(2011CBA00800)
文摘We applied a resistance split-fusion strategy to increase the in vivo direct cloning efficiency mediated by Red recombination. The cat cassette was divided into two parts： cma （which has a homologous sequence with cmb） and cmb, each of which has no resistance separately unless the two parts are fused together. The crab sequence was integrated into one flank of a target clon- ing region in the chromosome, and a linear vector containing the cma sequence was electroporated into the cells to directly capture the target region. Based on this strategy, we successfully cloned an approximately 48 kb DNA fragment from the E. coli DH1-Z chromosome with a positive frequency of approximately 80%. Combined with double-strand breakage-stimulated homologous recombination, we applied this strategy to successfully replace the corresponding region of the E. coli DH36 chromosome and knock out four non-essential genomic regions in one step. This strategy could provide a powerful tool for the heterologous expression of microbial natural product biosynthetic pathways for genome assembly and for the functional study of DNA sequences dozens of kilobases in length.
