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Fulltext The Microbiome and Irritable Bowel Syndrome - A Review on the Pathophysiology, Current Research and Future Therapy

Chong PP, Chin VK, Looi CY, Wong WF, Madhavan P, Yong VC

Front Microbiol, 2019;10:1136.
PMID: 31244784 DOI: 10.3389/fmicb.2019.01136

Irritable bowel syndrome (IBS) is a functional disorder which affects a large proportion of the population globally. The precise etiology of IBS is still unknown, although consensus understanding proposes IBS to be of multifactorial origin with yet undefined subtypes. Genetic and epigenetic factors, stress-related nervous and endocrine systems, immune dysregulation and the brain-gut axis seem to be contributing factors that predispose individuals to IBS. In addition to food hypersensitivity, toxins and adverse life events, chronic infections and dysbiotic gut microbiota have been suggested to trigger IBS symptoms in tandem with the predisposing factors. This review will summarize the pathophysiology of IBS and the role of gut microbiota in relation to IBS. Current methodologies for microbiome studies in IBS such as genome sequencing, metagenomics, culturomics and animal models will be discussed. The myriad of therapy options such as immunoglobulins (immune-based therapy), probiotics and prebiotics, dietary modifications including FODMAP restriction diet and gluten-free diet, as well as fecal transplantation will be reviewed. Finally this review will highlight future directions in IBS therapy research, including identification of new molecular targets, application of 3-D gut model, gut-on-a-chip and personalized therapy.

Matched MeSH terms: Gastrointestinal Microbiome
Developments in understanding and applying prebiotics in research and practice-an ISAPP conference paper

Scott KP, Grimaldi R, Cunningham M, Sarbini SR, Wijeyesekera A, Tang MLK, et al.

J Appl Microbiol, 2020 Apr;128(4):934-949.
PMID: 31446668 DOI: 10.1111/jam.14424

AIMS: The concept of using specific dietary components to selectively modulate the gut microbiota to confer a health benefit, defined as prebiotics, originated in 1995. In 2018, a group of scientists met at the International Scientific Association for Probiotics and Prebiotics annual meeting in Singapore to discuss advances in the prebiotic field, focussing on issues affecting functionality, research methodology and geographical differences.
METHODS AND RESULTS: The discussion ranged from examining scientific literature supporting the efficacy of established prebiotics, to the prospects for establishing health benefits associated with novel compounds, isolated from different sources.
CONCLUSIONS: While many promising candidate prebiotics from across the globe have been highlighted in preliminary research, there are a limited number with both demonstrated mechanism of action and defined health benefits as required to meet the prebiotic definition. Prebiotics are part of a food industry with increasing market sales, yet there are great disparities in regulations in different countries. Identification and commercialization of new prebiotics with unique health benefits means that regulation must improve and remain up-to-date so as not to risk stifling research with potential health benefits for humans and other animals.
SIGNIFICANCE AND IMPACT OF STUDY: This summary of the workshop discussions indicates potential avenues for expanding the range of prebiotic substrates, delivery methods to enhance health benefits for the end consumer and guidance to better elucidate their activities in human studies.

Matched MeSH terms: Gastrointestinal Microbiome
Fulltext Microbiome and colorectal cancer: an overview and local perspective

Rahman Jamal

Malaysian Journal of Medicine and Health Sciences, 2019;15(108):4-4.
MyJurnal

Colorectal cancer (CRC) is an important health problem that is on the rise globally, where it is the fourth most com-mon cause of deaths from cancer. CRC is now the 2nd commonest cancer in men and 3rd commonest in women in Malaysia. Diet, lifestyle, genetics and environmental interaction, together with underlying gut conditions such as inflammatory bowel disease have been reported to contribute to the disease. In addition, the gut microbiome has also been increasingly reported to be associated with CRC development, with dysbiosis of the commensal bacteria ob-served in CRC patients. Bacterial genera such as Bacteroides, Fusobacterium and Prevotella are more commonly de-tected in CRC patients compared to healthy individuals. Nevertheless, not much is known about the gut microbiome among Malaysians with different ethnicities. In Malaysia, the Chinese has the highest incidence of CRC, followed by Malays and Indians. The reason behind this difference may be contributed by the differences in the dietary intake that could modulate the gut microbiome and contribute towards the development of CRC. The current knowledge on this field still much depends on reports from individuals of American, European, Chinese, Brazilian and Japanese descendants in origin. The oncogenic potential of bacteria was suggested to include inflammation and the produc-tion of mutagenic toxin. A significant increase in certain intestinal microbiota including the genuses Enteroccus and Streptococcus spp. was detected in the advanced stage of colorectal adenoma. However, there are discrepancies in the previous studies, where some bacteria genera might be over-reported or underestimated. It is likely that the gut microbiome differs between populations. There is also no available data on the gut microbiome of the healthy individuals, colorectal adenoma (pre-cancerous) and colorectal cancer patients in the Malaysian population. Recent advancements in next generation sequencing allow faster and more accurate determination of microbial consortium in various niches of the human body and environment. In particular, sequencing of the 16S rRNA gene with specific primers have been reported to allow accurate determination of bacterial orders commonly found in the human gut as well as for those which are not expected in the digestive system. Recent developments in gut microbiome DNA ex-traction also contributed to the robustness of gut microbiome determination and analysis. All the above will contrib-ute towards an accurate and rapid cataloging process of the Malaysian gut microbiome and also enable comparison between healthy individuals, colorectal adenoma and CRC patients of the Malaysian population.

Matched MeSH terms: Gastrointestinal Microbiome
Fulltext Functional dyspepsia

Ford AC, Mahadeva S, Carbone MF, Lacy BE, Talley NJ

Lancet, 2020 11 21;396(10263):1689-1702.
PMID: 33049222 DOI: 10.1016/S0140-6736(20)30469-4

Dyspepsia is a complex of symptoms referable to the gastroduodenal region of the gastrointestinal tract and includes epigastric pain or burning, postprandial fullness, or early satiety. Approximately 80% of individuals with dyspepsia have no structural explanation for their symptoms and have functional dyspepsia. Functional dyspepsia affects up to 16% of otherwise healthy individuals in the general population. Risk factors include psychological comorbidity, acute gastroenteritis, female sex, smoking, use of non-steroidal anti-inflammatory drugs, and Helicobacter pylori infection. The pathophysiology remains incompletely understood, but it is probably related to disordered communication between the gut and the brain, leading to motility disturbances, visceral hypersensitivity, and alterations in gastrointestinal microbiota, mucosal and immune function, and CNS processing. Although technically a normal endoscopy is required to diagnose functional dyspepsia, the utility of endoscopy in all patients with typical symptoms is minimal; its use should be restricted to people aged 55 years and older, or to those with concerning features, such as weight loss or vomiting. As a result of our incomplete understanding of its pathophysiology, functional dyspepsia is difficult to treat and, in most patients, the condition is chronic and the natural history is one of fluctuating symptoms. Eradication therapy should be offered to patients with functional dyspepsia who test positive for Helicobacter pylori. Other therapies with evidence of effectiveness include proton pump inhibitors, histamine-2 receptor antagonists, prokinetics, and central neuromodulators. The role of psychological therapies is uncertain. As our understanding of the pathophysiology of functional dyspepsia increases, it is probable that the next decade will see the emergence of truly disease-modifying therapies for the first time.

Matched MeSH terms: Gastrointestinal Microbiome
Fulltext Predictors of advanced fibrosis in elderly patients with biopsy-confirmed nonalcoholic fatty liver disease: the GOASIA study

Pitisuttithum P, Chan WK, Piyachaturawat P, Imajo K, Nakajima A, Seki Y, et al.

BMC Gastroenterol, 2020 Apr 06;20(1):88.
PMID: 32252638 DOI: 10.1186/s12876-020-01240-z

BACKGROUND: The Gut and Obesity in Asia (GOASIA) Workgroup was formed to study obesity and gastrointestinal diseases in the Asia Pacific region. We aimed to 1) compare the characteristics of elderly (i.e. age ≥ 60) vs. non-elderly patients with biopsy-proven nonalcoholic fatty liver disease (NAFLD); 2) identify predictors of advanced fibrosis in elderly patients with NAFLD; and 3) assess the performance of non-invasive fibrosis scores in the prediction of advance fibrosis in the elderly population.
METHODS: We abstracted the data of 1008 patients with NAFLD from nine centers across eight countries. Characteristics of elderly and non-elderly patients with NAFLD were compared using 1:3 sex-matched analysis.
RESULTS: Of the 1008 patients, 175 were elderly [age 64 (62-67) years], who were matched with 525 non-elderly patients [46 (36-54) years]. Elderly patients were more likely to have advanced fibrosis (35.4% vs. 13.3%; p

Matched MeSH terms: Gastrointestinal Microbiome
Fulltext Association of antimicrobial resistance and gut microbiota composition in human and non-human primates at an urban ecotourism site

Chong CW, Alkatheeri AHS, Ali N, Tay ZH, Lee YL, Paramasivam SJ, et al.

Gut Pathog, 2020;12:14.
PMID: 32175011 DOI: 10.1186/s13099-020-00352-x

Background: The rise of nature-based ecotourism in the past decade has introduced unprecedented challenges in managing the increasing interaction between humans and animals. The potential transmission of antibiotic resistant microbes between humans and non-human primate populations is a concern due to their genetic similarity. Malaysia is well known for hotspots of wildlife diversity where non-human primates like monkeys and orangutans have become popular tourist attractions. In this study, we assessed the prevalence of antimicrobial resistant Staphylococcus aureus, Enterococcus species, and other Enterobacteriaceae in the faeces of human (HS) and two non-human primates (NHP) in Malaysia, the Long-tailed macaque (Macaca fascicularis, MF) and Silvered leaf monkey (Trachypithecus cristatus, TC). In addition, the faecal bacterial composition was profiled to evaluate the potential association between antibiotic resistant profiles and composition of gut microbiota.
Results: We tested the isolated bacteria using a selection of antibiotics. The results showed that both the number of antibiotic resistant strains and resistance level were higher in humans than NHPs. Overall, the composition of gut microbiome and pattern of antibiotic resistance showed that there was higher similarity between MF and TC, the two NHPs, than with HS. In addition, samples with higher levels of antibiotic resistance showed lower bacterial richness. Homo sapiens had the lowest bacterial diversity and yet it had higher abundance of Bacteroides. In contrast, NHPs displayed higher bacterial richness and greater prevalence of Firmicutes such as Ruminococceae and Oscillospira.
Conclusion: Higher antibiotic susceptibility in NHPs is likely related to low direct exposure to antibiotics. The lack of resistance may also suggest limited antimicrobial resistance transmission between humans and NHP. Nonetheless, continued monitoring over a long period will help mitigate the risk of anthropozoonosis and zooanthroponosis.

Matched MeSH terms: Gastrointestinal Microbiome
Fulltext Effects of graded dose dietary supplementation of Piper betle leaf meal and Persicaria odorata leaf meal on growth performance, apparent ileal digestibility, and gut morphology in broilers

Basit MA, Arifah AK, Loh TC, Saleha AA, Salleh A, Kaka U, et al.

Saudi J Biol Sci, 2020 Jun;27(6):1503-1513.
PMID: 32489287 DOI: 10.1016/j.sjbs.2020.04.017

Due to antimicrobial resistance and the public health hazard of antibiotic growth promoters, there is a grave need to find potential alternatives for sustainable poultry production. Piper betle (PB) and Persicaria odorata (PO) are herbs, which have been reported for antimicrobial, antioxidant, and anti-inflammatory properties. The present study aimed to estimate the influence of different dose supplementation of Piper betle leaf meal (PBLM) and Persicaria odorata leaf meal (POLM) on growth performance, ileal digestibility and gut morphology of broilers chickens. A total of 210 one day-old broiler chicks were randomly grouped into 7 treatments, and each treatment group has 3 replicates (n = 10) with a total number of 30 chicks. The treatments included T1 control (basal diet (BD) with no supplementation), T2 (BD + 2 g/kg PBLM); T3 (BD + 4 g/kg PBLM), T4 (BD + 8 g/kg PBLM), T5 (BD + 2 g/kg POLM), T6 (BD + 4 g/kg POLM), T7 (BD + 8 g/kg POLM). Growth performance, gut morphology and ileal digestibility were measured. Except for T4 (8 g/kg PBLM), graded dose inclusion of PBLM and POLM increased (P

Matched MeSH terms: Gastrointestinal Microbiome
Fulltext Heterometrus Spinifer: An Untapped Source of Anti-Tumor Molecules

Soopramanien M, Khan NA, Ghimire A, Sagathevan K, Siddiqui R

Biology (Basel), 2020 Jul 02;9(7).
PMID: 32630812 DOI: 10.3390/biology9070150

Despite intensive research, cancer incidence and mortality continue to rise. Consequently, the necessity to develop effective anti-cancer therapy is apparent. We have recently shown that the gut bacteria of animals living in polluted environments, such as crocodiles, are a potential source of novel anti-tumor molecules. To extend this work to other resilient species, we investigated the anti-tumor effects of gut bacteria of Heterometrus spinifer (a scorpion). Bacteria from the feces and gut were isolated, identified and evaluated for their anti-tumor effects. Bacterial-conditioned media was prepared in Roswell Park Memorial Institute (RPMI) 1640 media, and cytotoxicity and growth inhibitory properties were examined against cervical (HeLa) cancer cells. Liquid chromatography-mass spectrometry (LC-MS) was conducted to establish the identity of the molecules. Eighteen bacteria species from the gut (HSG01-18) and ten bacteria species from feces (HSF01-10) were tested for anti-tumor effects. Bacterial-conditioned media from scorpion gut and feces exhibited significant growth inhibitory effects against HeLa cells of 66.9% and 83.8%, respectively. Microscopic analysis of cancer cells treated with conditioned media HSG12 and HSG16 revealed apoptosis-like effects. HSG12 was identified as Pseudomonas aeruginosa and HSG16 was identified as Bacillus subtilis. Both conditioned media exhibited 100% growth inhibitory effects versus a selection of cancer cells, comprising cervical, breast and prostate cancer cells. LC-MS indicated the presence of 72 and 38 compounds, detected from HSG12 and HSG16, respectively. Out of these compounds, 47 were successfully identified while the remainder were unidentified and are possibly novel. This study suggests that the fecal and gut microbiota of scorpions might possess molecules with anti-cancer properties, however, further intensive research is needed to assess these expectations.

Matched MeSH terms: Gastrointestinal Microbiome
Fulltext Elucidating the Efficacy of Vaccination against Vibriosis in Lates calcarifer Using Two Recombinant Protein Vaccines Containing the Outer Membrane Protein K (r-OmpK) of Vibrio alginolyticus and the DNA Chaperone J (r-DnaJ) of Vibrio harveyi

Silvaraj S, Md Yasin IS, A Karim MM, Saad MZ

Vaccines (Basel), 2020 Nov 06;8(4).
PMID: 33171991 DOI: 10.3390/vaccines8040660

Recombinant cell vaccines expressing the OmpK and DnaJ of Vibrio were developed and subsequently, a vaccination efficacy trial was carried out on juvenile seabass (~5 cm; ~20 g). The fish were divided into 5 groups of 50 fish per group, kept in triplicate. Groups 1 and 2 were injected with 107 CFU/mL of the inactivated recombinant cells vaccines, the pET-32/LIC-OmpK and pET-32/LIC-DnaJ, respectively. Group 3 was similarly injected with 107 CFU/mL of inactivated E. coli BL21 (DE3), Group 4 with 107 CFU/mL of formalin killed whole cells V. harveyi, and Group 5 with PBS solution. Serum, mucus, and gut lavage were used to determine the antibody levels before all fish were challenged with V. harveyi, V. alginolyticus, and V. parahemolyticus, respectively on day 15 post-vaccination. There was significant increase in the serum and gut lavage antibody titers in the juvenile seabass vaccinated with r-OmpK vaccine. In addition, there was an up-regulation for TLR2, MyD88, and MHCI genes in the kidney and intestinal tissues of r-OmpK vaccinated fish. At the same time, r-OmpK triggered higher expression level of interleukin IL-10, IL-8, IL-1ß in the spleen, intestine, and kidney compared to r-DnaJ. Overall, r-OmpK and r-DnaJ triggered protection by curbing inflammation and strengthening the adaptive immune response. Vaccinated fish also demonstrated strong cross protection against heterologous of Vibrio isolates, the V. harveyi, V. alginolyticus, and V. parahaemolyticus. The fish vaccinated with r-OmpK protein were completely protected with a relative per cent of survival (RPS) of 90 percent against V. harveyi and 100 percent against V. alginolyticus and V. parahaemolyticus. A semi-quantitative PCR detection of Vibrio spp. from the seawater containing the seabass also revealed that vaccination resulted in reduction of pathogen shedding. In conclusion, our results suggest r-OmpK as a candidate vaccine molecule against multiple Vibrio strain to prevent vibriosis in marine fish.

Matched MeSH terms: Gastrointestinal Microbiome
Fulltext Colon Carcinogenesis: The Interplay Between Diet and Gut Microbiota

Loke YL, Chew MT, Ngeow YF, Lim WWD, Peh SC

Front Cell Infect Microbiol, 2020;10:603086.
PMID: 33364203 DOI: 10.3389/fcimb.2020.603086

Colorectal cancer (CRC) incidence increases yearly, and is three to four times higher in developed countries compared to developing countries. The well-known risk factors have been attributed to low physical activity, overweight, obesity, dietary consumption including excessive consumption of red processed meats, alcohol, and low dietary fiber content. There is growing evidence of the interplay between diet and gut microbiota in CRC carcinogenesis. Although there appears to be a direct causal role for gut microbes in the development of CRC in some animal models, the link between diet, gut microbes, and colonic carcinogenesis has been established largely as an association rather than as a cause-and-effect relationship. This is especially true for human studies. As essential dietary factors influence CRC risk, the role of proteins, carbohydrates, fat, and their end products are considered as part of the interplay between diet and gut microbiota. The underlying molecular mechanisms of colon carcinogenesis mediated by gut microbiota are also discussed. Human biological responses such as inflammation, oxidative stress, deoxyribonucleic acid (DNA) damage can all influence dysbiosis and consequently CRC carcinogenesis. Dysbiosis could add to CRC risk by shifting the effect of dietary components toward promoting a colonic neoplasm together with interacting with gut microbiota. It follows that dietary intervention and gut microbiota modulation may play a vital role in reducing CRC risk.

Matched MeSH terms: Gastrointestinal Microbiome
Fulltext The Potential of Mesenchymal Stromal Cell as Therapy in Neonatal Diseases

Liau LL, Al-Masawa ME, Koh B, Looi QH, Foo JB, Lee SH, et al.

Front Pediatr, 2020;8:591693.
PMID: 33251167 DOI: 10.3389/fped.2020.591693

Mesenchymal stromal cells (MSCs) can be derived from various tissue sources, such as the bone marrow (BMSCs), adipose tissue (ADSCs), umbilical cord (UC-MSCs) and umbilical cord blood (UCB-MSCs). Clinical trials have been conducted to investigate the potential of MSCs in ameliorating neonatal diseases, including bronchopulmonary dysplasia (BPD), intraventricular hemorrhage (IVH) and necrotizing enterocolitis (NEC). In preclinical studies, MSC therapy has been tested for the treatment of various neonatal diseases affecting the heart, eye, gut, and brain as well as sepsis. Up to date, the number of clinical trials using MSCs to treat neonatal diseases is still limited. The data reported thus far positioned MSC therapy as safe with positive outcomes. However, most of these trials are still preliminary and generally smaller in scale. Larger trials with more appropriate controls and a longer follow-up period need to be conducted to prove the safety and efficacy of the therapy more conclusively. This review discusses the current application of MSCs in treating neonatal diseases, its mechanism of action and future direction of this novel therapy, including the potential of using MSC-derived extracellular vesicles instead of the cells to treat various clinical conditions in the newborn.

Matched MeSH terms: Gastrointestinal Microbiome
Fulltext Comparative Efficacy of Selected Phytobiotics with Halquinol and Tetracycline on Gut Morphology, Ileal Digestibility, Cecal Microbiota Composition and Growth Performance in Broiler Chickens

Basit MA, Kadir AA, Loh TC, Abdul Aziz S, Salleh A, Zakaria ZA, et al.

Animals (Basel), 2020 Nov 19;10(11).
PMID: 33227911 DOI: 10.3390/ani10112150

The current experiment was designed to estimate the comparative efficacy of selected phytobiotics Persicaria odorata leaf meal (POLM) and Piper betle leaf meal (PBLM) with halquinol, and tetracycline in broiler chickens. The 150-day-old broiler chickens were randomly assigned to five dietary groups. The dietary supplementation groups were the basal diet (BD), which served as the negative control (NC), and BD + 0.2 g/kg tetracycline, which served as the positive control (PC); BD + 0.03 g/kg halquinol (HAL), BD + 8 g/kg POLM (Po8), and BD + 4 g/kg PBLM (Pb4) were the treatment groups. Growth performance, gut morphology, ileal digestibility, and cecal microbiota composition were measured. On day 21, the body weight gain (BWG) was enhanced (p < 0.05) in the broiler chickens fed on phytobiotics (Po8 and Pb4) relative to the NC group, however, on day 42 and in terms of overall growth performance, BWG was enhanced (p < 0.05 in diets (Po8, Pb4, HAL and PC) in comparison with the NC group. Conversely, feed conversion ratio (FCR) was recorded reduced (p < 0.05) in Pb4, Po8, HAL, and PC group in comparison with the NC group. Supplementation of phytobiotics (Po8 and Pb4), HAL and PC, positively improved the gut morphology compared to the NC group. Furthermore, the maximum (p < 0.05) villus height (VH) in duodenum and jejunum was observed in broilers fed on diet Pb4. Supplementation of phytobiotics, HAL and PC, improved (p < 0.05) the digestibility of dry matter (DM) (except for HAL), organic matter (OM), crude protein (CP), ether extract (EE), and ash compared to the NC group. Dietary supplementation of phytobiotics (Po8 and Pb4), HAL and PC, significantly reduced the E. coli, Salmonella, and Staphylococcus aureus (except for HAL) counts compared to the NC group. However, supplementation of Pb4 resulted in significantly decreased total anaerobic bacteria and Clostridium spp. counts compared to the NC group. In addition, supplementation of phytobiotics significantly increased the Lactobacillus count compared to HAL, PC, and NC groups. In conclusion, dietary supplementation of phytobiotics improved the gut morphology, positively modulated and maintained the dynamics of cecal microbiota with enhanced nutrient digestibility, thus, increased the growth performance. Based on current results, phytobiotics could be used as an alternative to AGPs for sustainable broiler chicken production.

Matched MeSH terms: Gastrointestinal Microbiome
Probiotic consumption relieved human stress and anxiety symptoms possibly via modulating the neuroactive potential of the gut microbiota

Ma T, Jin H, Kwok LY, Sun Z, Liong MT, Zhang H

Neurobiol Stress, 2021 May;14:100294.
PMID: 33511258 DOI: 10.1016/j.ynstr.2021.100294

Stress has been shown to disturb the balance of human intestinal microbiota and subsequently causes mental health problems like anxiety and depression. Our previous study showed that ingesting the probiotic strain, Lactobacillus (L.) plantarum P-8, for 12 weeks could alleviate stress and anxiety of stressed adults. The current study was a follow-up work aiming to investigate the functional role of the gut metagenomes in the observed beneficial effects. The fecal metagenomes of the probiotic (n = 43) and placebo (n = 36) receivers were analyzed in depth. The gut microbiomes of the placebo group at weeks 0 and 12 showed a significantly greater Aitchison distance (P

Matched MeSH terms: Gastrointestinal Microbiome
Fulltext Technology advancement enabling the link of gut microbiota with obesity and metabolic disorder

Hartini Yusof, Mohamad Shafiq Aazmi, Teh Lay Kek, Mohd Zaki Salleh, Ili Ng Abdullah, Aminuddin Ahmad, et al.

Jurnal Sains Kesihatan Malaysia, 2015;13(1):77-91.
MyJurnal

Obesity is a growing epidemic due to an accelerated phase of industrialization and urbanization with the overfed people
now outnumbered the underfed. It is the major public health problem with a lot of research interest as it is associated
with many complicated chronic disorders such as type-2 diabetes, cardiovascular diseases (CVD) and cancers. A global
estimation of 2.8 million deaths per year is due to obesity and there are tremendous on-going efforts to identify hosts
and environmental factors that infl uence the cause and pathogenesis of obesity. Concerted efforts from different research
groups had successfully shown that obese subjects have altered composition of gut microbiota and transplantation of this
microbiota infl uences body weight in the germ-free recipient mice. The advancement of technology had made possible
the study of gut microbiota which was unculturable for better understanding of their impact to human health. Rapid
deep sequencing of DNA at reasonable cost through various options of platforms followed by data analysis using robust
bioinformatic tools are an important way of analysing the gut microbiome. Here we review the role of gut microbiota
which modulates host’s metabolic functions and gene expression, facilitating the extraction and storage of energy from the
ingested dietary substances and leading to body-weight gain. We will discuss on the different techniques used, focusing
on the high-defi nition technologies for the determination of the composition, function and ecology of gut microbiota. This
allows the appropriate selection of platform which becomes the key for success of subsequent research.

Matched MeSH terms: Gastrointestinal Microbiome
Fulltext Bile Sensing: The Activation of Vibrio parahaemolyticus Virulence

Letchumanan V, Chan KG, Khan TM, Bukhari SI, Ab Mutalib NS, Goh BH, et al.

Front Microbiol, 2017;8:728.
PMID: 28484445 DOI: 10.3389/fmicb.2017.00728

Bacteria must develop resistance to various inhospitable conditions in order to survive in the human gastrointestinal tract. Bile, which is secreted by the liver, and plays an important role in food digestion also has antimicrobial properties and is able to disrupt cellular homeostasis. Paradoxically, although bile is one of the guts defenses, many studies have reported that bacteria such as Vibrio parahaemolyticus can sense bile and use its presence as an environmental cue to upregulate virulence genes during infection. This article aims to discuss how bile is detected by V. parahaemolyticus and its role in regulating type III secretion system 2 leading to human infection. This bile-bacteria interaction pathway gives us a clearer understanding of the biochemical and structural analysis of the bacterial receptors involved in mediating a response to bile salts which appear to be a significant environmental cue during initiation of an infection.

Matched MeSH terms: Gastrointestinal Microbiome
Antibacterial activity of selected invertebrate species

Ali SM, Siddiqui R, Sagathevan KA, Khan NA

Folia Microbiol (Praha), 2021 Apr;66(2):285-291.
PMID: 33704690 DOI: 10.1007/s12223-021-00860-6

The evolution of multiple-drug resistant bacteria is contributing to the global antimicrobial crisis, hence driving us to search for novel antimicrobial(s). Among animals, invertebrates represent up to 80% of all known species suggesting their wide distribution. Despite their ubiquitous and plentiful nature, they have been largely unexplored as potential source of antibacterials. In this study, we selected a broad range of invertebrates from terrestrial and marine environments and tested their lysates for antibacterial activity against methicillin-resistant Staphylococcus aereus (MRSA) and neuropathogenic Escherichia coli K1. Cockroaches, centipedes, tarantulas, prawns, lobster, and mud crabs showed antibacterial activity with selected lysates exhibiting more than 90% bactericidal effects. The red-headed centipede's hemolymph showed 90% and 50% bacteriostatic activity against MRSA and E. coli K1, respectively. Tarantula's body extracts exhibited antibacterial activity against MRSA and E. coli K1. Gut extracts of tiger prawn exhibited more than 90% bacteriostatic activity against both bacteria. The selected lobster and mud crab extract exhibited up to 90% growth inhibitory activity against MRSA. Overall, these results showed that selected invertebrates are an untapped source of broad-spectrum antibacterial activity and suggest the presence of biologically active molecules.

Matched MeSH terms: Gastrointestinal Microbiome
Fulltext Polyphenols as Prebiotics in the Management of High-Fat Diet-Induced Obesity: A Systematic Review of Animal Studies

Moorthy M, Sundralingam U, Palanisamy UD

Foods, 2021 Feb 02;10(2).
PMID: 33540692 DOI: 10.3390/foods10020299

Obesity is a disease growing at an alarming rate and numerous preclinical studies have proven the role of polyphenols in managing this disease. This systematic review explores the prebiotic effect of polyphenols in the management of obesity among animals fed on a high-fat diet. A literature search was carried out in PubMed, Scopus, CINAHL, Web of Science, and Embase databases following the PRISMA guidelines. Forty-four studies reported a significant reduction in obesity-related parameters. Most notably, 83% of the studies showed a decrease in either body weight/visceral adiposity/plasma triacylglyceride. Furthermore, 42 studies reported a significant improvement in gut microbiota (GM), significantly affecting the genera Akkermansia, Bacteroides, Blautia, Roseburia, Bifidobacteria, Lactobacillus, Alistipes, and Desulfovibrio. Polyphenols' anti-obesity, anti-hyperglycaemic, and anti-inflammatory properties were associated with their ability to modulate GM. This review supports the notion of polyphenols as effective prebiotics in ameliorating HFD-induced metabolic derangements in animal models.

Matched MeSH terms: Gastrointestinal Microbiome
Fulltext Gut Bacteria of Rattus rattus (Rat) Produce Broad-Spectrum Antibacterial Lipopeptides

Akbar N, Siddiqui R, Iqbal M, Sagathevan K, Kim KS, Habib F, et al.

ACS Omega, 2021 May 11;6(18):12261-12273.
PMID: 34056379 DOI: 10.1021/acsomega.1c01137

Among several animals, Rattus rattus (rat) lives in polluted environments and feeds on organic waste/small invertebrates, suggesting the presence of inherent mechanisms to thwart infections. In this study, we isolated gut bacteria of rats for their antibacterial activities. Using antibacterial assays, the findings showed that the conditioned media from selected bacteria exhibited bactericidal activities against Gram-negative (Escherichia coli K1, Klebsiella pneumoniae, Pseudomonas aeruginosa, Serratia marcescens, and Salmonella enterica) and Gram-positive (Bacillus cereus, methicillin-resistant Staphylococcus aureus, and Streptococcus pyogenes) pathogenic bacteria. The conditioned media retained their antibacterial properties upon heat treatment at boiling temperature for 10 min. Using MTT assays, the conditioned media showed minimal cytotoxic effects against human keratinocyte cells. Active conditioned media were subjected to tandem mass spectrometry, and the results showed that conditioned media from Bacillus subtilis produced a large repertoire of surfactin and iturin A (lipopeptides) molecules. To our knowledge, this is the first report of isolation of lipopeptides from bacteria isolated from the rat gut. In short, these findings are important and provide a platform to develop effective antibacterial drugs.

Matched MeSH terms: Gastrointestinal Microbiome
Fulltext Nutritional Support of Neurodevelopment and Cognitive Function in Infants and Young Children-An Update and Novel Insights

Cohen Kadosh K, Muhardi L, Parikh P, Basso M, Jan Mohamed HJ, Prawitasari T, et al.

Nutrients, 2021 Jan 10;13(1).
PMID: 33435231 DOI: 10.3390/nu13010199

Proper nutrition is crucial for normal brain and neurocognitive development. Failure to optimize neurodevelopment early in life can have profound long-term implications for both mental health and quality of life. Although the first 1000 days of life represent the most critical period of neurodevelopment, the central and peripheral nervous systems continue to develop and change throughout life. All this time, development and functioning depend on many factors, including adequate nutrition. In this review, we outline the role of nutrients in cognitive, emotional, and neural development in infants and young children with special attention to the emerging roles of polar lipids and high quality (available) protein. Furthermore, we discuss the dynamic nature of the gut-brain axis and the importance of microbial diversity in relation to a variety of outcomes, including brain maturation/function and behavior are discussed. Finally, the promising therapeutic potential of psychobiotics to modify gut microbial ecology in order to improve mental well-being is presented. Here, we show that the individual contribution of nutrients, their interaction with other micro- and macronutrients and the way in which they are organized in the food matrix are of crucial importance for normal neurocognitive development.

Matched MeSH terms: Gastrointestinal Microbiome
Fulltext Streptococcus mitis induces conversion of Helicobacter pylori to coccoid cells during co-culture in vitro

Khosravi Y, Dieye Y, Loke MF, Goh KL, Vadivelu J

PLoS One, 2014;9(11):e112214.
PMID: 25386948 DOI: 10.1371/journal.pone.0112214

Helicobacter pylori (H. pylori) is a major gastric pathogen that has been associated with humans for more than 60,000 years. H. pylori causes different gastric diseases including dyspepsia, ulcers and gastric cancers. Disease development depends on several factors including the infecting H. pylori strain, environmental and host factors. Another factor that might influence H. pylori colonization and diseases is the gastric microbiota that was overlooked for long because of the belief that human stomach was a hostile environment that cannot support microbial life. Once established, H. pylori mainly resides in the gastric mucosa and interacts with the resident bacteria. How these interactions impact on H. pylori-caused diseases has been poorly studied in human. In this study, we analyzed the interactions between H. pylori and two bacteria, Streptococcus mitis and Lactobacillus fermentum that are present in the stomach of both healthy and gastric disease human patients. We have found that S. mitis produced and released one or more diffusible factors that induce growth inhibition and coccoid conversion of H. pylori cells. In contrast, both H. pylori and L. fermentum secreted factors that promote survival of S. mitis during the stationary phase of growth. Using a metabolomics approach, we identified compounds that might be responsible for the conversion of H. pylori from spiral to coccoid cells. This study provide evidences that gastric bacteria influences H. pylori physiology and therefore possibly the diseases this bacterium causes.

Matched MeSH terms: Gastrointestinal Microbiome

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