• 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.

• Microbiology and Biotechnology Letters
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• v.42 no.3
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• pp.211-218
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• 2014

In order to isolate probiotic lactic acid bacteria possessing high inhibitory activities against porcine and zoonotic pathogens, such as enterotoxigenic E. coli, Salmonella Typhimurium, and Clostridium perfringens, a total of 65 anaerobic strains were initially isolated from a variety of sources including cattle rumen fluids, chicken intestines and swine feces. Four Bifidobacterium strains were selected for their high anti-pathogenic bacterial activities. By using the 16S rDNA sequencing method, three B. boum strains and one B. thermophilum were identified. B. thermophilum demonstrated the best adhesive ability to epithelial cells of swine intestine among the isolates. Indeed, B. thermophilum was seen to have superior characteristics as a probiotic for swine, as judged by their high growth inhibitory activities against various pathogens, and high acid- and bile-tolerance.

• Korean Journal of Organic Agriculture
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• v.15 no.1
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• pp.93-108
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• 2007

In order to find a solution to protect pigs from bacterial diarrhea and the nasty smell in stalls which are the most trouble, we composed a bio-formula with Stretococcus thermophilus, Bacillus amyloliquifaciens and Bacillu subtilis. The antagonistic microbe Bacillus amyloliquifaciens can control the growth of Salmonella typhimurium KCTC 1926, Escherichia coli O-157, Listeria and Staphylococcus. S. thermophilus from pig's stomach can live in gastric juice so it also control germs. They worked in its living cell state and its culture fluid. As a result of feeding with piglings, it showed effects of preventing diarrhea and increasing the weight.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2002.11a
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• pp.64-84
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• 2002

These studies were conducted to evaluate the Properties of lactic acid Producing bacteria(LAB), isolated from broiler and laying hens cecum and select the optimum strains to improve the performance, environment of poultry house, immunity, and intestinal microflora of broiler and laying hens. In experiment I , 23 LAB strains were isolated from broiler and laying hens cecum as a colony form. Six strains were selected by acid tolerance, bile salt tolerance, viability, enzyme release, antagonism, and antibiotics susceptibility. In Experiment II, selected LABs from Ex. 1 were conducted to investigate the effects of feeding various Lactobacillus on performance, nutrients digestibility, intestinal microflora, villi development and observation of epithelium surface, blood chemicals and fecal noxious gas of broiler chicks. One thousand eighty one day old broiler chicks were fed into Lactobacillus crispatus avibrol(LCB), Lactobacillus reuteri avibro2(LRB), Lactobacillus crispatus avihen1(LCH), and Lactobacillus vaginalis avihen2(LVH) at the level of 10$^4$ and 10$\^$7/cfu/g diet. Weight gam of chicks fed Lactobacillus tended to increase from the first week and was higher from 50 to 100g in Lactobacillus treatments than control. Feed intake and feed conversion were not statistically different of all treatments. Dry Matter digestibility of Lactobacillus treatments was prone to improve compared to that of control, but was not significantly different. Protein and Ca digestibility were also tended to improve in Lactobacillus treatments relative that of control. Lactobacillus treatments showed improved tendency in crude ash and fat compared to those of control, whereas phosphorus digestibility was not consistency. Nutrients digestibilities of bird fed LCH were superior to those of other treatments, It showed significantly higher in Ca and P digestibility than control(P〈0.05). Total Lactobacillus spp. of birds fed various Lactobacillus was significantly higher in illeum for five weeks(P〈0.05), but was not different at cecum. Yeast was thought to be not completely attached to intestinal lumen for one week. However, total number of yeast was significantly increased in cecum and illeum of three weeks old chicks (P〈0.05). The number of anaerobes exhibited to tendency the increase in Lactobacillus treatments from one week old of age at both ileum and cecum.

• Journal of Animal Science and Technology
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• v.47 no.4
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• pp.547-554
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• 2005

An experiment was conducted to investigate the dietary effects of a transgenic Aspergillus oryzae(AO) culture on the performance, egg quality and intestinal microflora of layers. A total of 840 Hy-line Brown layers of 39wks old were assigned to one of the following 7 dietary treatments: control(C), C+0.2% AO culture, C+0.5% AO culture, C+0.2% transgenic AO culture, C+0.5% transgenic AO culture, C+0.2% transgenic mutant AO culture, and C+0.5% transgenic mutant AO culture. The transgenic AO was made by inserting Salmonella gallinarum gene to AO. And the transgenic mutant AO was made by inserting Salmonella gallinarum gene to mutant AO which was mutated by UV irradiation. Each treatment was replicated six times with 20 birds housed in 2 bird cage. Twenty birds units were arranged according to completely randomized block design. Feeding trial lasted for 8wks under 16 hour lighting regimen. Laying performance and egg quality were significantly(P<0.05) affected by the treatments. Transgenic AO culture supplementation at the level of 0.2% significantly increased egg production, while its egg weight was significantly decreased compared to that of the control. Feed intake and feed conversion ratio(FCR) were not significantly different among the AO treatments and the control. The eggshell strength of the AO treatments was significantly higher than that of the control. Transgenic mutant AO culture supplemented at the level of 0.5% significantly increased egg yolk color. Intestinal microflora were significantly(P<0.05) affected by the treatments. The cfu of Lactobacilli spp. significantly increased and those of Salmonella species and E. coli decreased in the AO treatments. The transgenic AO and transgenic mutant AO culture were more effective than the AO culture in reducing the cfu of Salmonella species and E. coli. It is concluded that supplementation of the transgenic AO culture at the level of 0.2% could be recommended for the improvement of egg production. Supplementation of transgenic AO or transgenic mutant AO culture at 0.2% level effectively controlled intestinal Salmonella species population.

• The Journal of the Korean Society for Microbiology
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• v.10 no.1
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• pp.13-17
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• 1975

The authors identified fourty-seven Shigella cultures among 1504 suspectable cultures of enteric pathogens collected from all over the country in 1974. Fourty-three out of fourty-seven cultures belonged to Shigella flexneri, three to Shigella sonnei and the rest to Shigella dysenteriae, and none of cultures belonging to subgroup C was detected in 1974. Three Shigella flexneri 2a cultures were isolated in Seoul area, but the others in Kangwon-Do. All the Shigella cultures were sensitive to nitrofurantoin, cephalosporin, ampicillin and penicillin G $1{\mu}g$, but resistant to bacitracin, lincomycin and penicillin V. $10{\mu}g$ by means of the In-Vitro tests.

• Journal of Life Science
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• v.32 no.1
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• pp.36-43
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• 2022

Mucosal immunity is a well-designed defense system that builds precise and dynamic relationships against pathogens, and the gastrointestinal tract is the most important organ with this system, acting as a guardian at the forefront of its activity. Salmonella spp. cause food poisoning, entering the body orally and mainly invading the Peyer's patches of the small intestine. Although Salmonella strains share similar mechanisms for inducing innate immunity, different serotypes may have different effects on the intestinal mucosa due to host specificities and pathogenicity. In this study, we evaluated the effects of Salmonella enteritidis infections in mouse intestine and observed significantly reduced dose-dependent survival rates in a challenge test. Flow cytometry data showed no significant differences in intestinal immune cell populations, although histology indicated increased mucin production and decreased goblet cell counts in the Salmonella-treated groups. Furthermore, Claudin expression was significantly decreased in the samples with Salmonella. To investigate the relationship between S. enteritidis infection and inflammatory response, dextran sodium sulfate (DSS) was administered after infection and the results indicate lower survival rate after DSS treatment. In conclusion, we were able to identify the optimal concentration of S. enteritidis to modulate the intestinal mucosal immunity of mice and inflammatory response.

• Food Science of Animal Resources
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• v.26 no.2
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• pp.263-268
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• 2006

Probiotics including Lactobacillus acidophilus, refer to a group of nonpathogenic organisms that protect the human host against gastrointestinal(GI) infections by pathogenic bacteria such as Shiga toxin-producing E. coli(STEC). In the study, the inhibitory effects of STEC ATCC 43894 adhesion by L. acidophilus A4 was investigated on the HT-29 epithelial cells. Specific proteins regulated by cell Iysates of L. acidophilus A4 on STEC ATCC 43894 were also characterized by proteomic analysis. Both cell mass and Iysate of L. acidophilus A4 have exhibited the profound inhibitory activity on the HT-29 cells(about 1.5 log scale reduction). Two-dimensional gel electrophoresis(2-DE) revealed seven proteins that were up-regulated by cell Iysates of L. acidophilus A4 and three proteins that were down-regulated. In addition, three protein spots were only detected in the presence of cell Iysates. These results suggest that inhibitory effects of STEC adhesion by L. acidophilus may be due to the regulation of specific protein of STEC.

• The Journal of the Korean Society for Microbiology
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• v.14 no.1
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• pp.1-9
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• 1979

A bacteriological survey was carried out to get hold of the distribution of pathogenic enteric bacteria in Korea. The total number of 2,013 specimens were obtained from various sources; 1,407 specimens from marine products circulated in the markets, sewage, and 606 rectal swabs from persons. All the specimens were collected in Seoul, Chumunjin(Kangwondo), and Gwangcheon(Chungcheongnam-do) during 1978. The isolation and identification of enteric pathogens from the specimens were performed by means of bacteriological studies. 1. The isolation rates of the pathogenic enterobacteria among the total 2,013 specimens are as follows: Salmonella species 0.05%(1 strain), Shigella species 0.50%(10 strains), and Vibrio parahaemolyticus 0.35%(7 strains). 2. One salmonella strain was isolated from marine products circulated in the market in Seoul. Its serotype was identified as group $C_1$. 3. Ten shigella strains were isolated from various sources: 0.45% from natural environments and 0.05% from rectal swabs. The distribution of shigella serotype was identified as Sh. boydii 90%(9 strains), Sh. sonnei 10%(1 strain). 4. Seven strains of V. parahaemolyticus were isolated from natural environments. In addition, 40 strains of halophilic vibrios nontypable with anti-K antisera were also isolated. Of the 7 strains, the 2 strains were agglutinated with type K-32, each 1 strain of the others with K-17, K-19, K-36, K-39, K-56.

• The Journal of the Korean Society for Microbiology
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• v.19 no.1
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• pp.41-48
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• 1984

The present study was undertaken to elucidate the antibacterial spectrum of L. casei phage type $J_1$ strain isolated from a fermented milk product against pathogenic enteric bacteria. Growth inhibitory effects and minimum inhibitory concentration(MIC) of culture supernatants of L. casei grown in MRS broth were measured by both plate culture method and microplate broth dilution technique against Salmonella typhi, Salmonella typhimurium, Shigella flexneri, Shigella dysenteriae, enterpathogenic E. coli, Klebsiella pneumoniae and Pseudomonas aeruginosa. The results are summarized as follows: 1. The MRS broth culture of L. casei gave a similar extent of growth inhibitory effects against S. typhi, S. typhimurium, S. flexneri, S. dysenteriae, E. coli, K. pneumoniae and P. aeruginosa, respectively. 2. The inhibitory effects of L. casei culture were observed either in whole broth culture or in culture supernatant, but neither the bacterial suspension nor the neutralized culture supernatant showed such as antibacterial activities. 3. The MIC titres of the culture supernatants were ${\log_2}5$ to ${\log_2}6$, whereas those of the neutralized culture supernatant dropped markdely to ${\log_2}2$ to ${\log_2}3$. These results indicated that major portion of growth inhibitory effects of MRS broth culture of L. casei against enteric bacterial pathogens was possibly due to the acids produced, and minor portion to other antibacterial substances.