• Journal of Dairy Science and Biotechnology
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• v.25 no.2
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• pp.21-28
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• 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
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• 2007.09a
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• pp.21-29
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• 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.

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

• Archives of Pharmacal Research
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• v.29 no.5
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• pp.348-353
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• 2006

In this study, a 40% ethanol extract of Chinese yam flour (Dioscoreae rhizoma), containing $177{\pm}58{\mu}g/mL$ of dioscin, was tested in order to evaluate its pharmacological effects on the gastrointestinal tracts of Sprague-Dawley rats. Via the ingestion of the Chinese yam extract, the secretion of gastric acid was suppressed in the rats, and gastrointestinal motility increased by as much as 10%. The fecal quantity of rats fed on the Chinese yam extract also increased, by more than 40% as compared with that of the controls. The Chinese yam extract was found not to affect the growth of normal intestinal bacteria. However, a great deal of lactose-fermenting bacteria was observed in the fecal samples of rats fed for 6 weeks on 2% Chinese yam extract. This finding would appear to suggest that Chinese yam extract not only induces an improvement in digestive capability, but also affects the conversion of some intestinal flora to helpful bacteria. Our serochemical analyses indicated that serum glucose, neutral lipid, and total cholesterol levels were reduced to some degree by long-term feeding on Chinese yam extract. This finding bolsters the notion that Chinese yam extract may prove helpful as a digestion-aiding agent for patients suffering from hyperglycemia or hyperlipidemia.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.6
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• pp.898-906
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• 2014

The objective of this study was to investigate differences in the faecal microbial composition among Lantang, Bama, Erhualian, Meishan, Xiaomeishan, Duroc, Landrace, and Yorkshire sows and to explore the possible link of the pig breed with the gut microbial community. Among the sows, the Meishan, Landrace, Duroc, and Yorkshire sows were from the same breeding farm with the same feed. Fresh faeces were collected from three sows of each purebred breed for microbiota analysis and volatile fatty acid (VFA) determination. Denaturing gradient gel electrophoresis (DGGE) analysis revealed that samples from Bama, Erhualian, and Xiaomeishan sows, which from different farms, were generally grouped in one cluster, with similarity higher than 67.2%, and those from Duroc, Landrace, and Yorkshire sows were grouped in another cluster. Principal component analysis of the DGGE profile showed that samples from the foreign breeds and the samples from the Chinese indigenous breeds were scattered in two different groups, irrespective of the farm origin. Faecal VFA concentrations were significantly affected by the pig breed. The proportion of acetate was higher in the Bama sows than in the other breeds. The real-time PCR analysis showed that 16S rRNA gene copies of total bacteria, Firmicutes and Bacteroidetes were significantly higher in the Bama sows compared to Xiaomeishan and Duroc sows. Both Meishan and Erhualian sows had higher numbers of total bacteria, Firmicutes, Bacteroidetes and sulphate-reducing bacteria as compared to Duroc sows. The results suggest that the pig breed affects the composition of gut microbiota. The microbial composition is different with different breeds, especially between overseas breeds (lean type) and Chinese breeds (relatively obese type).

• Microbiology and Biotechnology Letters
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• v.26 no.6
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• pp.471-475
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• 1998

The aim of the present research program was to develop a strain of gastrointestinal bacteria containing antitumor substances. Fecal samples were collected from neonates and a number of gastrointestinal bacteria were isolated from the fecal samples by applying selective agar for intestinal bacteria. Among 127 isolates, a strain 2B4-1 containing an antitumor substance against stomach cancer, SNU-1, was selected. The strain 2B4-1 was identified as a strain similar to Enterococcus faecalis NCTC 775 with respect to morphological characteristics, growth temperature, salt and acid tolerance, growth under facultative anaerobic conditions and utilization of carbon sources such as arabinose and melibiose and so on. However, it showed some differences such as a negative reaction to hippurate hydrolysis and negative reaction to $\beta$-hemolysis. We assigned to the strain 2B4-1 to Enterococcus faecalis.

• Journal of Microbiology and Biotechnology
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• v.9 no.1
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• pp.98-105
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• 1999

Intestinal bacteria comprise one-third of the contents of the large intestine in humans. Their interactions with the gastrointestinal immune system induce characteristic immunological responses which stimulate or suppress the host's defense system. RAW 264.7 murine cell line was used as a macrophage model to assess the effects of the exposure to the isolated human intestinal bacteria, Bacteroides, Bifidobacterium, Eubacterium, Streptococcus, and E. coli, on NO (nitric oxide), $H_2O_2$(hydrogen peroxide), and cytokines IL (interleukin)-6 and TNF (tumor necrosis factor)-a production. RAW 264.7 cells were cultured in the presence of heat-killed bacteria for 24 h at concentrations of 0-$50\mu$g/ml. Our results showed that Bacteroides and E. coli stimulated IL-6, TNF-$\alpha$, NO, and $H_2O_2$production at high levels even at $1\mu$g/ml, whereas Bifidobacterium, Eubacterium, and Streptococcus showed a low level of stimulation at $1\mu$g/ml, and a gradual increase as the cell concentration increased up to $50\mu$g/ml. This result suggests that gram-negative Bacteroides and E. coli are better able to stimulate macrophage than gram-positive Bifidobacterium, Streptococcus, and Eubacterium. The in vitro approaches employed here should be useful in further characterization of the effects of intestinal bacteria on gastrointestinal and systemic immunity.

• Korean Journal of Microbiology
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• v.51 no.1
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• pp.61-67
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• 2015

Recently, change of Western pattern diet and lifestyle is caused by various metabolic disorders and chronic diseases. These diseases need to take medicine regularly. Also, many people take health functional food, various vitamins and nutritional supplements in order to maintain a healthy life. But, there was no study about affects taking medicines against bacteria with gastrointestinal relevance. This study was performed by antibacterial activity test to evaluate the influence of a long time or commonly used medication. As a result, medicines of Vitamins & Minerals or Central nervous system show antibacterial activity against beneficial enteric bacteria and harmful enteric bacteria. Dexibuprofen of the Anti-inflammatory Drugs that acts on the central nervous system has shown high antibacterial activity at beneficial enteric bacteria strains (Lactobacillus casei, Lactobacillus rhamnosus) and harmful enteric bacteria (Staphylococcus aureus). Also, fenofibric acid of the antilipemic agents that acts on the Cardiovascular & Hematopoietic system has shown high antibacterial activity at beneficial enteric bacteria strains (Lactobacillus casei). Vitamins & Minerals appeared antibacterial activity against most intestinal bacteria. Vitamin B-Complex/with C and vitamin C were especially high with beneficial enteric bacteria strains (Bifidobacterium infantis) and harmful enteric bacteria (E. coli, E. aerogenes, S. flexneri, S. Typhimurium, S. aureus). Therefore, these results indicate that variously taking medicines have generally antibacterial activity against harmful enteric bacteria strains and beneficial enteric bacteria strains.

• Journal of Life Science
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• v.32 no.5
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• pp.391-410
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• 2022

Human microbiota is a community of microorganisms, including bacteria, fungi, and viruses, that inhabit various locations of the body, such as the gut, oral, and skin. Along with the development of metabolomic analysis and next-generation sequencing techniques for 16S ribosomal RNA, it has become possible to analyze the population for subtypes of microbiota, and with these techniques, it has been demonstrated that bacterial microbiota are involved in the metabolic and immunological processes of the hosts. While specific bacteria of microbiota, called commensal bacteria, positively affect hosts by producing essential nutrients and protecting hosts against other pathogenic microorganisms, dysbiosis, an abnormal microbiota composition, disrupts homeostasis and thereby has a detrimental effect on the development and progression of various types of diseases. Recently, several studies have reported that oral and gut bacteria of microbiota are involved in the carcinogenesis of gastrointestinal tumors and the therapeutic effects of anticancer therapy, such as radiation, chemotherapy, targeted therapy, and immunotherapy. Studying the complex relationships (bacterial microbiota-cancer-immunity) and microbiota-related carcinogenic mechanisms can provide important clues for understanding cancer and developing new cancer treatments. This review provides a summary of current studies focused on how bacterial microbiota affect gastrointestinal cancer and anticancer therapy and discusses compelling possibilities for using microbiota as a combinatorial therapy to improve the therapeutic effects of existing anticancer treatments.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.8
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• pp.1088-1097
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• 2014

The study aimed to investigate the effects of gynosaponin on in vitro methanogenesis under different forage-concentrate ratios (F:C ratios). Experiment was conducted with two kinds of F:C ratios (F:C = 7:3 and F:C = 3:7) and gynosaponin addition (0 mg and 16 mg) in a $2{\times}2$ double factorial design. In the presence of gynosaponin, methane production and acetate concentration were significantly decreased, whereas concentration of propionate tended to be increased resulting in a significant reduction (p<0.05) of acetate:propionate ratio (A:P ratio), in high-forage substrate. Gynosaponin treatment increased (p<0.05) the butyrate concentration in both F:C ratios. Denaturing gradient gel electrophoresis (DGGE) analysis showed there was no apparent shift in the composition of total bacteria, protozoa and methanogens after treated by gynosaponin under both F:C ratios. The real-time polymerase chain reaction (PCR) analysis indicated that variable F:C ratios significantly affected the abundances of Fibrobacter succinogenes, Rumninococcus flavefaciens, total fungi and counts of protozoa (p<0.05), but did not affect the mcrA gene copies of methanogens and abundance of total bacteria. Counts of protozoa and abundance of F.succinogenes were decreased significantly (p<0.05), whereas mcrA gene copies of methanogens were decreased slightly (p<0.10) in high-forage substrate after treated by gynosaponin. However, gynosaponin treatment under high-concentrate level did not affect the methanogenesis, fermentation characteristics and tested microbes. Accordingly, overall results suggested that gynosaponin supplementation reduced the in vitro methanogenesis and improved rumen fermentation under highforage condition by changing the abundances of related rumen microbes.