• Journal of Microbiology and Biotechnology
• /
• v.24 no.4
• /
• pp.447-452
• /
• 2014

To isolate novel and useful microbial enzymes from uncultured gastrointestinal microorganisms, a fecal microbial metagenomic library of the pygmy loris was constructed. The library was screened for amylolytic activity, and 8 of 50,000 recombinant clones showed amylolytic activity. Subcloning and sequence analysis of a positive clone led to the identification a novel gene (amyPL) coding for ${\alpha}$-amylase. AmyPL was expressed in Escherichia coli BL21 (DE3) and the purified AmyPL was enzymatically characterized. This study is the first to report the molecular and biochemical characterization of a novel ${\alpha}$-amylase from a gastrointestinal metagenomic library.

• Asian-Australasian Journal of Animal Sciences
• /
• v.33 no.12
• /
• pp.1948-1956
• /
• 2020

Objective: The purpose of this study was to reveal the metabolic shift in the fungus cocultured with the methanogen (Methanobrevibacter thaueri). Methods: Gas chromatography-mass spectrometry was used to investigate the metabolites in anaerobic fungal (Pecoramyces sp. F1) cells and the supernatant. Results: A total of 104 and 102 metabolites were detected in the fungal cells and the supernatant, respectively. The partial least squares-discriminant analysis showed that the metabolite profiles in both the fungal cell and the supernatant were distinctly shifted when co-cultured with methanogen. Statistically, 16 and 30 metabolites were significantly (p<0.05) affected in the fungal cell and the supernatant, respectively by the co-cultured methanogen. Metabolic pathway analysis showed that co-culturing with methanogen reduced the production of lactate from pyruvate in the cytosol and increased metabolism in the hydrogenosomes of the anaerobic fungus. Citrate was accumulated in the cytosol of the fungus co-cultured with the methanogen. Conclusion: The co-culture of the anaerobic fungus and the methanogen is a good model for studying the microbial interaction between H₂-producing and H₂-utilizing microorganisms. However, metabolism in hydrogenosome needs to be further studied to gain better insight in the hydrogen transfer among microorganisms.

• Asian-Australasian Journal of Animal Sciences
• /
• v.14 no.4
• /
• pp.567-586
• /
• 2001

Gastrointestinal tract of ruminants as well as monogastric animals are colonised by a variety of microorganisms including bacteria, fungi and protozoa. Gastrointestinal ecosystem, especially the rumen is emerging as an important source for enrichment and natural selection of microbes adapted to specific conditions. It represents a virtually untapped source of novel products (e.g. enzymes, antibiotics, bacteriocins, detoxificants and aromatic compounds) for industrial and therapeutic applications. Several gastrointestinal bacteria and fungi implicated in detoxification of anti-nutritional factors (ANFs) can be modified and manipulated into promising system for detoxifying feed stuffs and enhancing fibre fermentation both naturally by adaptation or through genetic engineering techniques. Intestinal lactobacilli, bifidobacteria and butyrivibrios are being thoroughly investigated and widely recommended as probiotics. Restriction endonucleases and native plasmids, as stable vectors and efficient DNA delivery systems of ruminal and intestinal bacteria, are increasingly recognised as promising tools for genetic manipulation and development of industrially useful recombinant microbes. Enzymes can improve the nutrient availability from feed stuffs, lower feed costs and reduce release of wastes into the environment. Characterization of genes encoding a variety of commercially important enzymes such as cellulases, xylanases, $\beta$-glucanases, pectinases, amylases and phytases will foster the development of more efficacious and viable enzyme supplements and enzyme expression systems for enhancing livestock production.

• Journal of Dairy Science and Biotechnology
• /
• v.25 no.2
• /
• pp.21-28
• /
• 2007

Recently, the field of microbiology has been transformed by huge increasing number of publicly available whole-genome sequences. This sequence information has significantly enhanced our understanding of the physiology, genetics, and evolutionary development of bacteria. Among the gastrointestinal microorganisms, bifidobacteria represent the most important human commensals because of their contribution to maintaining a balanced gastrointestinal tract microbiota. In recent years bifidobacteria have drawn much scientific attention due to their use as live bacteria in numerous food products with various health-related claims. For this reason, these bacteria constitute a growing area of interest with respect to genomics, molecular biology, and genetics. Recent genome sequencing of a number of bifidobacterial species has allowed access to the complete genetic make-up of these bacteria. This review will focus how genomic data has allowed us to understand bifidobacterial evolution, while also revealing genetic functions that explains their presence in the particular ecological environment of the gastrointestinal tract.

• 한국유가공학회:학술대회논문집
• /
• 2007.09a
• /
• pp.21-29
• /
• 2007

The field of microbiology has in recent years been transformed by huge increasing number of publicly available whole-genome sequences. This sequence information has significantly enhanced our understanding of the physiology, genetics, and evolutionary development of bacteria. Among the gastrointestinal microorganisms, bifidobacteria represent important human commensals because of their perceived contribution to maintaining a balanced gastrointestinal tract microbiota. In recent years bifidobacteria have drawn much scientific attention due to their use as live bacteria in numerous food products with various health-related claims. For this reason, these bacteria constitute a growing area of interest with respect to genomics, molecular biology, and genetics. Recent genome sequencing of a number of bifidobacterial species has allowed access to the complete genetic make-up of these bacteria. This review will focus how genomic data has allowed us to understand bifidobacterial evolution, while also revealing genetic functions that explains their presence in the particular ecological environment of the gastrointestinal tract.

• Journal of Animal Science and Technology
• /
• v.63 no.6
• /
• pp.1464-1467
• /
• 2021

Bacillus coagulans CACC 834 was isolated from canine feces, and its potential probiotic properties were characterized by functional genome analysis. Whole-genome sequencing of B. coagulans CACC 834 was performed using the PacBio RSII platforms. The complete genome assembly consisted of one circular chromosome (3.1 Mb) with guanine (G) + cytosine (C) content of 47.1%. Annotation revealed 3,181 protein-coding sequences (CDSs), 30 rRNAs, and 83 tRNAs. Gene associated 11% of the genes were involved in replication, recombination, and repair. We also annotated various stress-related, acid resistance, bile salt resistance and adhesion-related domains in this strain, which likely provide support in exerting probiotic action by survival under gastrointestinal tract. These results add to our comprehensive understanding of B. coagulans and suggest potential mammal-related industrial applications.

• Journal of Dairy Science and Biotechnology
• /
• v.21 no.2
• /
• pp.125-137
• /
• 2003

Bifidobacteria are normal inhabitants of the human gastrointestinal tract throughout lift, starting just days after birth, and are one of several predominant species of the colonic microflora, along with Peptostreptococcus, Eubacteria, Clostridia, and Bacteroides. Bifidobacteria differ from lactic acid bacteria in that they produce not only lactic acid but also acetic acid as major fermentation products. The classification of bifidobacteria has changed numerous times since they were discovered in 1899 in the feces of breast-fed infants. Since 1994, three additional species have been included in the list (B. lactis, B. inopinatum, and B. denticolens), with a current total of 32 species. A variety of probiotic effects of bifidobacteria are currently being investigated. Research reports suggests several potential probiotic advantages, in particular antimicrobial effects, immune-modulation reduction of the cancer risk, and modulation of gastrointestinal flora. As technological challenges related to viability and enumeration are being overcome, milks fermented with these anaerobic microorganisms(alone or in combination with lactic acid bacteria) are more able to provide consistently satisfying with large numbers of viable microorganisms. Over 70 products containing bifidobacteria are currently offered around the world, including fermented milks, cheese, buttermilk frozen desserts, candy, and pharmaceutical preparations.

• Asian-Australasian Journal of Animal Sciences
• /
• v.18 no.10
• /
• pp.1505-1512
• /
• 2005

Bile salt deconjugation is the most biologically significant reaction among the bacterial alterations of bile acids in the gastrointestinal tract of human and animal. The responsible enzyme, bile salt hydrolase (BSH), catalyzes the hydrolysis of glycineand/or taurine-conjugated bile salts into amino acid residues and deconjugated bile acids. Herein we review current knowledge on the distribution of BSH activity among various microorganisms with respect to their biochemical and molecular characteristics. The proposed physiological impact of BSH activity on the host animal as well as on the BSH-producing bacterial cells is discussed. BSH activity of the probiotic strains is examined on the basis of BSH hypothesis, which was proposed to explain cholesterol-lowering effects of probiotics. Finally, the potential applications of BSH research are briefly discussed.

• Pediatric Gastroenterology, Hepatology & Nutrition
• /
• v.27 no.1
• /
• pp.1-14
• /
• 2024

Probiotics are live microorganisms that confer health benefits to the host when administered in adequate amounts. Although recommendations for probiotic use should be strain-specific, many systematic reviews, including recommendations from different societies, recommend probiotic use in general, providing no relevant information for healthcare professionals regarding which probiotic to recommend for which clinical indication, at what dose, and for how long. This narrative review aimed to present the available evidence on the use of probiotics in the prevention and treatment of common gastrointestinal diseases in children, considering the strain and dose used. Furthermore, this study summarizes the evidence on the possible side effects and quality of products containing probiotics.

• Journal of Microbiology and Biotechnology
• /
• v.20 no.10
• /
• pp.1367-1377
• /
• 2010

Scientific research regarding the use of live bacterial cells for therapeutic purposes has been rapidly growing over the years and has generated considerable interest to scientists and health professionals. Probiotics are defined as essential live microorganisms that, when administered in adequate amounts, confer a health benefit on the host. Owing to their considerable beneficial health effects, these microorganisms are increasingly incorporated into dairy products; however, many reports have demonstrated their poor survival and stability. Their survival in the gastrointestinal tract is also questionable. To overcome these problems, microencapsulation techniques are currently receiving considerable attention. This review describes the importance of live probiotic bacterial microencapsulation using an alginate microparticulate system and presents the potentiality of various coating polymers such as chitosan and polylysine for improving the stability of this microencapsulation.