Influence of gut bacteria on type 2 diabetes:Mechanisms and therapeutic strategy

The onset and progression of type 2 diabetes mellitus(T2DM)are strongly associated with imbalances in gut bacteria,making the gut microbiome a new potential therapeutic focus.This commentary examines the recent publication in World Journal of Diabetes.The article explores the association between T2DM and gut microbiota,with a focus on the pathophysiological changes related to dysbiosis.It proposes innovative microbiome-targeted therapeutic strategies and evaluates the challenges and future directions of such approaches.This editorial summarizes the key points of their discussion of the role of the gut microbiome in T2DM and elaborates on the influence of specific gut microbial species on the disease through the host–microbiota metabolic axis.It provides new insights for future research on gut-microbiota-based interventions for T2DM.

Isolation of bacteria from fermented food and grass carp intestine and their efficiencies in improving nutrient value of soybean meal in solid state fermentation

Background: Soybean meal is an excellent and cost-effective protein source; however, its usage is limited in the piglet due to the presence of anti-nutritional factors and the antigens glycinin and β-conglycinin. The objective of the current study was to screen and select for bacteria that can be efficiently adopted to ferment soybean meal in order to solve this problem.Results: Bacteria were isolated from fermented soy foods and the grass carp intestine, and strains selected for high protease, cellulase and amylase activities. The isolated bacteria were characterized as Bacillus cereus, Bacillus subtilis and Bacilus amyloliquefacien, respectively. Fermentation with food-derived Isolate-2 and fish-derived F-9 increased crude protein content by 5.32% and 8.27%, respectively; improved the amino acid profile by increasing certain essential amino acids, broke down larger soy protein to 35 k Da and under, eliminated antigenicity against glycinin and β-conglycinin, and removed raffinose and stachyose in the soybean meal following a 24-h fermentation.Conclusions: Our results suggest these two B. amyloliquefaciens bacteria can efficiently solid state ferment soybean meal and ultimately produce a more utilizable food source for growing healthy piglets.

Fucoxanthin Isolated from Undaria pinnatifida Can Interact with Escherichia coli and lactobacilli in the Intestine and Inhibit the Growth of Pathogenic Bacteria

Fucoxanthin is a xanthophyll-type carotenoid that provides many benefits to human health. However, the mechanism by which fucoxanthin interacts with microbes and inhibits pathogenic bacteria is unknown. In this study, we investigated the effects of fucoxanthin isolated from the edible seaweed Undaria pinnatifida on pathogenic bacteria Escherichia coli and lactobacilli both in vitro and in vivo. Fucoxanthin strongly inhibited the growth of Gram-positive pathogenic bacteria but was less effective against Gram-negative bacteria. Fucoxanthin extracted from the crude mixture had a recovery rate of 93.38% and a purity of 82.70%, which were higher than those of fucoxanthin extracted using a previous method. Fucoxanthin also promoted the growth of intestinal mi- crobes in mice. Fucoxanthinol, a metabolite of fucoxanthin, was generated in the culture media. Fucoxanthin can be deacetylated into fucoxanthinol not only by conventional digestive enzymes in the digestive tract, but also by E. coli and lactobacilli in the intestine. These results indicate that fucoxanthin interacts with and influences E. coli and lactobacilli in the intestine. Therefore, fucoxanthin isolated from Undaria pinnatifida possibly can be applied in human health maintenance.

Ability of lactulose breath test results to accurately identify colorectal polyps through the measurement of small intestine bacterial overgrowth

BACKGROUND While colorectal polyps are not cancerous,some types of polyps,known as adenomas,can develop into colorectal cancer over time.Polyps can often be found and removed by colonoscopy;however,this is an invasive and expensive test.Thus,there is a need for new methods of screening patients at high risk of developing polyps.AIM To identify a potential association between colorectal polyps and small intestine bacteria overgrowth(SIBO)or other relevant factors in a patient cohort with lactulose breath test(LBT)results.METHODS A total of 382 patients who had received an LBT were classified into polyp and non-polyp groups that were confirmed by colonoscopy and pathology.SIBO was diagnosed by measuring LBTderived hydrogen(H)and methane(M)levels according to 2017 North American Consensus recommendations.Logistic regression was used to assess the ability of LBT to predict colorectal polyps.Intestinal barrier function damage(IBFD)was determined by blood assays.RESULTS H and M levels revealed that the prevalence of SIBO was significantly higher in the polyp group than in the non-polyp group(41%vs 23%,P<0.01;71%vs 59%,P<0.05,respectively).Within 90 min of lactulose ingestion,the peak H values in the adenomatous and inflammatory/hyperplastic polyp patients were significantly higher than those in the non-polyp group(P<0.01,and P=0.03,respectively).In 227 patients with SIBO defined by combining H and M values,the rate of IBFD determined by blood lipopolysaccharide levels was significantly higher among patients with polyps than those without(15%vs 5%,P<0.05).In regression analysis with age and gender adjustment,colorectal polyps were most accurately predicted with models using M peak values or combined H and M values limited by North American Consensus recommendations for SIBO.These models had a sensitivity of≥0.67,a specificity of≥0.64,and an accuracy of≥0.66.CONCLUSION The current study made key associations among colorectal polyps,SIBO,and IBFD and demonstrated that LBT has moderate potential as an alternative noninvasive screening tool for colorectal polyps.

Spatial organization of bacterial flora in normal and inflamed intestine: A fluorescence in situ hybridization study in mice

AIM: To studythe role of intestinal flora in inflammatory bowel disease (IBD).METHODS: The spatial organization of intestinal flora was investigated in normal mice and in two models of murine colitis using fluorescence in situ hybridization.RESULTS: The murine small intestine was nearly bacteriafree. The normal colonic flora was organized in three distinct compartments (crypt, interlaced, and fecal), each with different bacterial compositions. Crypt bacteria were present in the cecum and proximal colon. The fecal compartment was composed of homogeneously mixed bacterial groups that directly contacted the colonic wall in the cecum but were separated from the proximal colonic wall by a dense interlaced layer. Beginning in the middle colon, a mucus gap of growing thickness physically separated all intestinal bacteria from contact with the epithelium. Colonic inflammation was accompanied with a depletion of bacteria within the fecal compartment, a reduced surface area in which feces had direct contact with the colonic wall, increased thickness and spread of the mucus gap, and massive increases of bacterial concentrations in the crypt and interlaced compartments. Adhesive and infiltrative bacteria were observed in inflamed colon only, with dominant Bacteroides species.CONCLUSION: The proximal and distal colons are functionally different organs with respect to the intestinal flora, representing a bioreactor and a Segregation device.The highly organized structure of the colonic flora, its specific arrangement in different colonic segments, and its specialized response to inflammatory stimuli indicate that the intestinal flora is an innate part of host immunity that is under complex control.

Production of corticotropin-releasing factor and urocortin from human monocyte-derived dendritic cells is stimulated by commensal bacteria in intestine

AIM: To examine whether commensal bacteria are a contributing cause of stress-related mucosal inflammation.

Small intestine bacterial overgrowth and irritable bowel syndrome-related symptoms:Experience with Rifaximin

AIM： TO estimate the prevalence of small intestinal bacterial overgrowth （SIBO） in our geographical area （Western Sicily, Italy） by means of an observational study, and to gather information on the use of locally active, non-absorbable antibiotics for treatment of SIBO.METHODS： Our survey included 115 patients fulfilling the Rome II criteria for diagnosis of irritable bowel syndrome （IBS）; a total of 97 patients accepted to perform a breath test with lactulose （BTLact）, and those who had a positive test, received Rifaximin （Normix , Alfa Wassermann） 1200 mg/d for 7 d; 3 wk after the end of treatment, the BTLact was repeated.RESULTS： Based on the BTLact results, SIBO was present in about 56% of IBS patients, and it was responsible for some IBS-related symptoms, such as abdominal bloating and discomfort, and diarrhoea. 1-wk treatment with Rifaximin turned the BTLact to negative in about 50% of patients and significantly reduced the symptoms, especially in those patients with an alternated constipation/diarrhoea-variant IBS. CONCLUSION： SIBO should be always suspected in patients with IBS, and a differential diagnosis is done by means of a ＂breath test＂. Rifaximin may represent a valid approach to the treatment of SIBO.

Bacterial diversity in the intestine of young farmed puffer fish Takifugu rubripes

The aim of the study was to examine the bacterial community associated with the intestinal mucus of young farmed puffer fish Takifugu rubripes. Polymerase chain reaction and partial 16 S r DNA sequencing was performed on DNA from bacteria cultivated on Zobell 2216 E medium. All the isolates were classified into two phyla—Proteobacteria and Firmicutes. Proteobacteria were the dominant, culturable intestinal microbiota(68.3%). At the genus level, V ibrio, Enterobacter, Bacillus, Pseudomonas, Exiguobacterium, Staphylococcus, Acinetobacter, Pseudoalteromonas and S hewanella were isolated from the intestine, with representatives of the genera V ibrio, Enterobacter and Bacillus accounting for 70.7% of the total. This is the first report of Enterobacter, Bacillus, Exiguobacterium and Staphylococcus as part of the intestinal bacterial microflora in T. rubripes. The profile of the culturable bacterial community differed between samples collected from the same tank at 2-month intervals, as indicated by Bray-Curtis and Sorensen indices, and the impact on the intestinal physiology and health of puffer fish requires further investigation.

Fermentative Biohydrogen Production with Enteric Bacteria Isolated from the Intestine of Wild Common Carp Dwelling in Tarim River Basin

The biological hydrogen generating from fermentation of low-cost lignocellulosic feedstocks by hydrogen-producing bacteria has attracted many attentions in recent years. In the present investigation, ten hydrogen-producing bacteria were newly isolated from the intestine of wild common carp (Cyprinus carpio L.), and identified belonging to the genera of Enterobacter and Klebsiella based on analysis of the 16S rDNA gene sequence and examination of the physiological and biochemical characteristics. All the isolates inherently owned the ability to metabolize xylose especially the cotton stalk hydrolysate for hydrogen production with hydrogen yield (HY) higher than 100 mL·L-1. In particular, two isolates, WL1306 and WL1305 obtained higher HY, hydrogen production rate (HPR), and hydrogen production potential (HPP) using cotton stalk hydrolysate as sugar substrate than the mixed sugar of glucose & xylose, which obtained the HY of 249.5 ± 29.0, 397.0 ± 36.7 mL·L-1, HPR of 10.4 ± 1.2, 16.5 ± 1.5 mL·L-1·h-1, HPP of 19.5 ± 2.3, 31.0 ± 2.8 mL·L-1·g-1sugar, separately. The generation of soluble metabolites, such as the lactate, formate, acetate, succinate and ethanol reflected the mixed acid fermentation properties of the hydrogen production pathway.

Insight into the spoilage heterogeneity of meat-borne bacteria isolates with high-producing collagenase

Chilled chicken is inevitably contaminated by microorganisms during slaughtering and processing,resulting in spoilage.Cutting parts of chilled chicken,especially wings,feet,and other skin-on products,are abundant in collagen,which may be the primary target for degradation by spoilage microorganisms.In this work,a total of 17 isolates of spoilage bacteria that could secrete both collagenase and lipase were determined by raw-chicken juice agar(RJA)method,and the results showed that 7 strains of Serratia,Aeromonas,and Pseudomonas could significantly decompose the collagen ingredients.The gelatin zymography showed that Serratia liquefaciens(F5)and(G7)had apparent degradation bands around 50 kDa,and Aeromonas veronii(G8)and Aeromonas salmonicida(H8)had a band around.65 and 95 kDa,respectively.The lipase and collagenase activities were detected isolate-by-isolate,with F5 showing the highest collagenase activity.For spoilage ability on meat in situ,F5 performed strongest in spoilage ability,indicated by the total viable counts,total volatile basic nitrogen content,sensory scores,lipase,and collagenase activity.This study provides a theoretical basis for spoilage heterogeneity of strains with high-producing collagenase in meat.

Isolation,identification,and evaluation of intestinal bacteria in Macrobrachium rosenbergii

Probiotics are live microbial food supplements that have been shown to have beneficial effects on animal health.Endogenous probiotic bacteria have long been used for their proposed health promoting properties and have become a hot research topic in growth improvement in aquaculture.The endogenous probiotic bacteria from intestines of Macrobrachium rosenbergii(giant river prawn)was explored for their probiotic potential,from which 367 bacterial strains were isolated from the intestine of M.rosenbergii.After 16 S rDNA sequence analysis,234 isolates were identified as Lactococcus garvieae,which accounted for 63.76%of the total number of culturable intestinal bacteria,suggesting that this bacterium was the main component of the microbiota.Furthermore,to reveal the probiotic properties of L.garvieae,this isolated bacterial strain was characterized morphologically,physiologically,and biochemically.Its enzyme production capacity,bacteriostatic activity,and resistance to acid,high temperature,and pH,were assessed.In vitro experiments showed that the L.garvieae(No.C 6 a 2)had a fast growth rate and entered the logarithmic phase rapidly.Besides,it had characteristics of acid-production and resistance,enzyme-producing capacity,and strong antibacterial activity against pathogenic Staphylococc us aureus,Aeromonas hydrophila,and Aeromonas veronii.However,it lacked the ability to tolerate high temperature.Our results provide novel data to deepen our understanding of the intestinal bacteria structure of M.rosenbergii and valuable information for probiotic screening and the application for M.rosenbergii.

Multifunctional role of oral bacteria in the progression of nonalcoholic fatty liver disease

Non-alcoholic fatty liver disease(NAFLD)encompasses a spectrum of liver disorders of varying severity,ultimately leading to fibrosis.This spectrum primarily consists of NAFL and non-alcoholic steatohepatitis.The pathogenesis of NAFLD is closely associated with disturbances in the gut micr-obiota and impairment of the intestinal barrier.Non-gut commensal flora,particularly bacteria,play a pivotal role in the progression of NAFLD.Notably,Porphyromonas gingivalis,a principal bacterium involved in periodontitis,is known to facilitate lipid accumulation,augment immune responses,and induce insulin resistance,thereby exacerbating fibrosis in cases of periodontitis-associated NAFLD.The influence of oral microbiota on NAFLD via the“oral-gut-liver”axis is gaining recognition,offering a novel perspective for NAFLD management through microbial imbalance correction.This review endeavors to encapsulate the intricate roles of oral bacteria in NAFLD and explore underlying mechanisms,emphasizing microbial control strategies as a viable therapeutic avenue for NAFLD.

GSDMD protects intestinal epithelial cells against bacterial infections through its N-terminal activity affecting intestinal immune homeostasis

The intestinal mucosal barrier serves as a vital guardian of the gut health,maintaining a delicate equilibrium between gut microbiota and host immune homeostasis.Gasdermin D(GSDMD),a key executioner of pyroptosis downstream of the inflammasome,has been found to play intricate roles in modulating colitis by influencing intestinal macrophages and regulating mucus secretion from goblet cells.However,the exact nature of the regulatory function of GSDMD in maintaining intestinal immune homeostasis and defending against pathogens remains to be elucidated.In the current study,by using the Citrobacter rodentium infection model,we found that GSDMD played a key role in the defense against intestinal Citrobacter rodentium infection,with high expression levels in intestinal epithelial and lamina propria myeloid cells.Our results showed that GSDMD acted specifically in intestinal epithelial cells to combat the infection,independently of its effects on antimicrobial peptides or mucin secretion.Instead,the resistance was mediated by the N-terminal fragment of GSDMD,highlighting its importance in intestinal immunity.However,the specific mechanism underlying the N-terminal activity of GSDMD in protecting against intestinal bacterial infections requires future investigation.

Modern approaches for detection of volatile organic compounds in metabolic studies focusing on pathogenic bacteria:Current state of the art

Pathogenic microorganisms produce numerous metabolites,including volatile organic compounds(VOCs).Monitoring these metabolites in biological matrices(e.g.,urine,blood,or breath)can reveal the presence of specific microorganisms,enabling the early diagnosis of infections and the timely implementation of tar-geted therapy.However,complex matrices only contain trace levels of VOCs,and their constituent com-ponents can hinder determination of these compounds.Therefore,modern analytical techniques enabling the non-invasive identification and precise quantification of microbial VOCs are needed.In this paper,we discuss bacterial VOC analysis under in vitro conditions,in animal models and disease diagnosis in humans,including techniques for offline and online analysis in clinical settings.We also consider the advantages and limitations of novel microextraction techniques used to prepare biological samples for VOC analysis,in addition to reviewing current clinical studies on bacterial volatilomes that address inter-species in-teractions,the kinetics of VOC metabolism,and species-and drug-resistance specificity.

Preparation of lactic acid bacteria compound starter cultures based on pasting properties and its improvement of glutinous rice flour and dough

The effects of 5 lactic acid bacteria(LAB)fermentation on the pasting properties of glutinous rice flour were compared,and suitable fermentation strains were selected based on the changes of viscosity,setback value,and breakdown value to prepare LAB compound starter cultures.The results revealed that Latilactobacillus sakei HSD004 and Lacticaseibacillus rhamnosus HSD005 had apparent advantages in increasing the viscosity and reducing the setback and breakdown values of glutinous rice flour.In particular,the compound starter created using the two abovementioned LAB in the ratio of 3:1 had better performance than that using a single LAB in improving the pasting properties and increasing the water and oil absorption capacity of glutinous rice flour.Moreover,the gelatinization enthalpy of the fermented samples increased significantly.For frozen glutinous rice dough stored for 28 days,the viscoelasticity of frozen dough prepared by compound starter was better than that of control dough,and the freezable water content was lower than that of control dough.These results indicate that compound LAB fermentation is a promising technology in the glutinous rice-based food processing industry,which has significance for its application.

Identification of an intestine-specific promoter and inducible expression of bacterial α-galactosidase in mammalian cells by a lac operon system

Background： o-galactosidase has been widely used in animal husbandry to reduce anti-nutritional factors （such as o-galactoside） in feed. Intestine-specific and substrate inducible expression of a-galactosidase would be highly beneficial for transgenic animal production. Methods： To achieve the intestine-specific and substrate inducible expression of o-galactosidase, we first identified intestine-specific promoters by comparing the transcriptional activity and tissue specificity of four intestine-specific promoters from human intestinal fatty acid binding protein, rat intestinal fatty acid binding protein, human mucin-2 and human lysozyme. We made two chimeric constructs combining the promoter and enhancer of human mucin-2, rat intestinal trefoil factor and human sucrase-isomaltase. Then a modified lac operon system was constructed to investigate the induction of o-galactosidase expression and enzyme activity by isopropyl p-D-]-thiogalactopyranoside （IPTG） and an a-galactosidase substrate, a-lactose. We declared that the research carried out on human （Zhai Yafeng） was in compliance with the Helsinki Declaration and experimental research on animals also followed internationally recognized guidelines. Results： The activity of the human mucin-2 promoter was about 2 to 3 times higher than that of other intestine-specific promoters. In the/ac operon system, the repressor significantly decreased （P 〈 0.05） luciferase activity by approximately 6.5-fold and reduced the percentage of cells expressing green fluorescent protein （GFP） by approximately 2-fold. In addition, the expression level of o-galactosidase mRNA was decreased by 6-fold and a-galactosidase activity was reduced by 8-fold. in line with our expectations, IPTG and a-lactose supplementation reversed （P 〈 O.O5） the inhibition and produced a 5-fold increase of luciferase activity, an 11-fold enhancement in the percentage of cells with GFP expression and an increase in o-galactosidase mfiNA abundance （by about 5-fold） and o-galactosidase activity （by about 7-fold）. Conclusions： We have successfully constructed a high specificity inducible lac operon system in an intestine-derived cell line, which could be of great value for gene therapy applications and transgenic animal production.

Effect of Supplementation of Conjugated Linoleic Acid in Diets on Growth Performance and Total Lactic Bacteria iin Small Intestine of Broiler

The effect of supplementation of conjugated linoleic acid （CLA） in diets on growth performance and total lactic bacteria （LAB） in small intestine of broiler. One hundred sixty eight broilers （Arbor Acres; 1 wk old） were randomly assigned to 8 groups. Each group （male 21 and female 21 broiler chickens） was further randomly divided into 3 replicates of 7 chickens were assigned to 4 dietary treatments （0%, 0.5%, 1.0%, and 1.5% CLA）. Feed consumption and BW were recorded at every 7-day period. On day 56, and each week were collected at ileal content in small intestine for the total count of lactic acid bacteria （LAB）. There were highly significant differences in body weight gain, average dairy feed intake, average dairy gain and feed conversion ratio among the treatments （P 〈 0.01）. Moreover, our results revealed that the highest detection trend from the ileal occurred during the period in the supplementation of CLA.

Antiseptic Efficacy of A Soap Made from Biosurfactants Isolated from Bacillus and Lactobacillus against Pathogenic Bacteria

The aim of our study was to use a biosurfactant produced by Bacillus and Lactobacillus isolates as an antiseptic in the formulation of local soap. A total of 60 isolates were characterized by microbiological techniques (30 Bacillus and 30 Lactobacillus) and the ability to produce biosurfactants was demonstrated by a hydrocarbon emulsification index (E24). The emulsification indexes (E24) varied from 9% to 100% for Bacillus and from 33% to 100% for Lactobacillus as well. The antagonistic assay showed that biosurfactants were able to inhibit the formation of biofilms and growth of pathogens such as Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus cereus, Salmonella typhirium, Shigella boydii and Proteus mirabilis. The biosurfactant consortium (BioC) from Bacillus consortium and from Lactobacillus was able to inhibit biofilm formation and the pathogens growth. The BioC was stable to alkaline pH and the temperatures stability of Biosurfactant was ranging from 50°C to 90°C. The soap was made by the cold saponification process using one biosurfactant consortium formulated. This soap has a pH of 10 and showed good cleaning power and good foam stability. Similarly, the soap showed good antiseptic power and disinfection power against all pathogens tested. Handwashing is critical to preventing disease transmission. The persistence of pathogens in waste water was evaluated. The BioS produced showed good disinfection power against all pathogens tested. The valor of reduction on the hands and in the waste water was significantly more than compared to the control soaps used. This soap could be used in the prevention, fighting, and treatment of bacterial and viral infections.

Diarrheal Diseases: A Review on Gastroenteritis Bacteria Global Burden and Alternative Control of Multidrug-Resistant Strains

Diarrheal diseases represent a significant and pervasive health challenge for humanity. The aetiology of diarrheal diseases is typically associated with the presence of enteropathogens, including viruses, bacteria and parasites. The implementation of preventive measures, including the maintenance of good food hygiene, effective water sanitation, and the development of rotavirus vaccines, has resulted in a notable reduction in the prevalence of the disease. However, the emergence of bacterial multidrug resistance due to the past or present inappropriate use of antibiotics has rendered bacterial infections a significant challenge. The objective of this review is threefold: firstly, to provide an overview of diarrheal diseases associated with bacteria;secondly, to offer a concise analysis of bacterial multidrug resistance on a global scale;and thirdly, to present the potential of filamentous fungi as an alternative solution to the challenge posed by multidrug-resistant strains. Campylobacter spp. is the most dangerous bacteria, followed by Shigella spp. and Vibrio cholerae in all age groups combined. However, Shigella spp. was the deadliest in children under five years of age and, together with E. coli, are the most antibiotic-resistant bacteria. With their highly developed secondary metabolism, fungi are a reservoir of natural bioactive compounds.

The Preliminary Study on Screening and Application of Phthalic Acid-Degrading Bacteria

Phthalic acid is a main pollutant, which is also an important reason for the continuous cropping effect of tobacco. In order to degrade the phthalic acid accumulated in the environment and relieve the obstacle effect of tobacco continuous cropping caused by the accumulation of phthalic acid in the soil. In this study, phthalate degrading bacteria B3 is screened from continuous cropping tobacco soil. The results of biochemical identification and 16sDNA comparison show that the homology between degrading bacterium B3 and Enterobacter sp. is 99%. At the same time, the growth of Enterobacter hormaechei subsp. B3 and the degradation of phthalic acid under different environmental conditions are studied. The results show that the environment with a temperature of 30˚C, PH of 7, and inoculation amount of not less than 1.2%, which is the optimal growth conditions for Enterobacter sp. B3. In an environment with a concentration of phthalic acid not exceeding 500 mg/L, Enterobacter sp. B3 has a better effect on phthalic acid degradation, and the degradation rate can reach 77% in 7 d. The results of indoor potting experiments on tobacco show that the degradation rate of phthalic acid by Enterobacter B3 in the soil is about 45%, which can reduce the inhibitory effect of phthalic acid on the growth of tobacco seedlings. This study enriches the microbial resources for degrading phthalic acid and provides a theoretical basis for alleviating tobacco continuous cropping obstacles.