• Journal of Life Science
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• v.27 no.11
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• pp.1290-1298
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• 2017

Intestinal microbiota is an important factor in the development of immune defense mechanisms in the human body. Treatments with anticancer agents, such as 5-Fluorouracil, Cisplatin, and Oxaliplatin, significantly change the temporal stability and environment of intestinal bacterial flora. The anticancer treatment chemotherapy often depresses the immune system and induces side effects, such as diarrhea. This study investigated the effects anticancer agents have on the intestinal microbial ecosystems of patients with gastric cancer. An exploration of the diversity and temporal stability of the dominant bacteria was undertaken using a DGGE with the 16S rDNA gene. Researchers collected stool samples from patients zero, two and eight weeks after the patients started chemotherapy. After the treatment with anticancer agents, the bacteria strains Sphingomonas paucimobilis, Lactobacillus gasseri, Parabacteroides distasonis and Enterobacter sp. increased. This study focused on the survival of the beneficial microorganisms Bifidobacterium and Lactobacillus in the intestines of cancer patients. The administration of antigastric cancer agents significantly decreased Lactobacillus and Bifidobacterium populations and only moderately affected the main bacterial groups in the patients' intestinal ecosystems. The results showed the versatility of a cultivation independent-PCR DGGE analysis regarding the visual monitoring of ecological diversity and anticancer agent-induced changes in patients' complex intestinal microbial ecosystems.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.10
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• pp.1528-1539
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• 2019

Objective: To evaluate the effects on microbial diversity and biochemical parameters of gradually increasing temperatures, from $5^{\circ}C$ to $25^{\circ}C$ on corn silage which was previously fermented at ambient or low temperature. Methods: Whole-plant corn silage was fermented in vacuum bag mini-silos at either $10^{\circ}C$ or $20^{\circ}C$ for two months and stored at $5^{\circ}C$ for two months. The mini-silos were then subjected to additional incubation from $5^{\circ}C$ to $25^{\circ}C$ in $5^{\circ}C$ increments. Bacterial and fungal diversity was assessed by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) profiling and biochemical analysis from mini-silos collected at each temperature. Results: A temperature of $10^{\circ}C$ during fermentation restricted silage fermentation compared to fermentation temperature of $20^{\circ}C$. As storage temperature increased from $5^{\circ}C$ to $25^{\circ}C$, little changes occurred in silages fermented at $20^{\circ}C$, in terms of most biochemical parameters as well as bacterial and fungal populations. However, a high number of enterobacteria and yeasts (4 to $5\;log_{10}$ colony forming unit/g fresh materials) were detected at $15^{\circ}C$ and above. PCR-DGGE profile showed that Candida humilis predominated the fungi flora. For silage fermented at $10^{\circ}C$, no significant changes were observed in most silage characteristics when temperature was increased from $5^{\circ}C$ to $20^{\circ}C$. However, above $20^{\circ}C$, silage fermentation resumed as observed from the significantly increased number of lactic acid bacteria colonies, acetic acid content, and the rapid decline in pH and water-soluble carbohydrates concentration. DGGE results showed that Lactobacillus buchneri started to dominate the bacterial flora as temperature increased from $20^{\circ}C$ to $25^{\circ}C$. Conclusion: Temperature during fermentation as well as temperature during storage modulates microorganism population development and fermentation patterns. Silage fermented at $20^{\circ}C$ indicated that these silages should have lower aerobic stability at opening because of better survival of yeasts and enterobacteria.

• Korean journal of applied entomology
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• v.48 no.3
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• pp.369-375
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• 2009

A commercial egg parasitoid, Trichogramma sp. Nabis101, was released into agricultural cultivating areas in Korea due to its wide host spectrum against insect pests. Moreover, an application technique has been recently developed to enhance its control efficacy by mixture treatment with a microbial control agent. Despite its expansion of commercial availability, any genetic identification on this commercial strain was not determined. Also, to meet inconsistent demands from consumers, the live parasitoids need to be stored without significant loss of their survival and parasitic activity. This study determined nucleotide sequence of internal transcribed spacer (ITS) of the wasp species. The identified ITS sequences indicate that this wasp species is most similar to T brasiliensis. Optimal storage condition of this wasp required young parasitized stage at $10^{\circ}C$. Under these conditions, survival, sex ratio, longevity, and parasitic behavior were not much impaired for 5 weeks.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.1
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• pp.90-95
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• 2010

The application of livestock manure to cropland is a practice that has been used for centuries. Agricultural crops can utilize nutrients from manure, and the producer can utilize land for disposal, although in a "sustainable system" the concept is manure utilization and not waste disposal. However, meeting regulatory criteria regarding microbial quality remains an expensive and time consuming process. The purpose of this study was to quantify the level of environmental impact of soil moisture and temperature on fecal coliform (Escherichia coli or E. coli) survival in upland soils for sound application of livestock manure. Samples were collected up to 30 days depending on the given conditions. The inactivation rate of E. coli increased linearly with increased temperature while the inactivation rate gradually decreased with decreased soil moisture level. The overall findings of this study showed that the temperature was the limited factor on E. coli survival in soils over soil moisture content. This study will provide useful and practical guidelines to applicators of soil in deciding appropriate handling and time frames for land application for sustainable agriculture.

• Journal of Applied Biological Chemistry
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• v.55 no.2
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• pp.123-127
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• 2012

In order to develop eco-friendly biopesticide, an entomopathogenic bacterium Photorhabdus temperata M1021 has been lyophilized via freeze-drying along with protective agents such as skim milk, starch, sodium alginate, glucose and sodium glutamate to protect cells from lysis. Freeze-drying powder of P. temperata M1021 containing 7% skim milk (w/v) showed highest survival rate of 63% among all the protective agents used in trials. Furthermore, the freeze-dried microbial powder showed 75% of survival rate after stored at $4^{\circ}C$ for 4 weeks at air contact conditions. Injection toxicity of the freeze-dried sample was tested against larvae of Galleria mellonella. A dose of $2.0{\times}10^1$ cells of P. temperata M1021 killed 100% of the G. mellonella larvae within 4 days after injection. Moreover, $2.0{\times}10^0$ cells caused 50% mortality within the 4 days after injection. Freeze-dried P. temperata M1021 strains exhibited effective insecticidal activity and could be a better candidate for being used as a biopesticide.

• Korean Journal of Food Science and Technology
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• v.53 no.5
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• pp.657-668
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• 2021

We prepared the growth and survival models of enterohemorrhagic Escherichia coli (EHEC) and Campylobacter jejuni in milk as a function of temperature and assessed the microbiological risks associated with the consumption of whole milk. EHEC and C. jejuni were not detected in whole milk (n=195) in the retail market. The minimum growth temperature of EHEC in milk was 7℃. The lag time of EHEC in whole milk was longer than that in skim milk. The survival ability of C. jejuni in milk was better at 4℃ than at 10℃. Lower delta values were observed in whole milk than in skim milk, indicating that C. jejuni survived better in skim milk. The probability of foodborne illness from whole milk consumption was 5.70×10^-5 for EHEC and 9.86×10^-9 for C. jejuni. Sensitivity analysis results show that the market temperature of EHEC and the dose-response model of C. jejuni are correlated with the probability of foodborne illness.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.8
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• pp.1243-1251
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• 2007

This study was conducted to evaluate the feasibility of using L. reuteri Pg4, a strain isolated from the gastrointestinal (GI) tract of healthy broilers, as a probiotic. In preliminary in vitro studies the Pg4 strain was proven capable of tolerating acid and bile salts, inhibiting pathogenic bacteria and can adhere to intestinal epithelial cells. The probiotic properties were then evaluated on the basis of the broiler's growth performance, intestinal microbial population and cecal volatile fatty acid and lactic acid concentrations under conventional feeding. Dietary supplementation of dried L. reuteri Pg4 decreased significantly feed intake in grower chickens and improved significantly the feed conversion by 5% in a 0-6 weeks feeding period compared with the control group. The Lactobacillus counts in the crop, ileum, and cecum of the probiotic group were higher than in the control group. The L. reuteri Pg4 strain was traceable in the GI tract of probiotic supplemented chicks and showed capability of survival in the intestine for a protracted period. The probiotic group had a higher lactic acid concentration and lower pH value in the cecum than the control chicks. Probiotic supplement also affected the histology of the intestinal mucosa of chicks. The present findings demonstrated that L. reuteri Pg4 possesses probiotic characteristics and it is suggested, therefore, that the organism could be a candidate for a new probiotic strain.

• The Journal of the Korean Society for Microbiology
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• v.34 no.5
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• pp.435-443
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• 1999

Orientia tsutsugamushi is obligate intracellular bacterium that grows within the cytoplasm of the eukaryotic host cells. Therefore capability of the attachment, entry into the host cell and intracellular survival should be critical process for oriential infection. In this study we investigated the cellular invasion mechanism of Orientia tsutsugamushi and the role of transmembrane heparan sulfate proteoglycan, which binds diverse components at the cellular microenvironment and is implicated as host cell receptors for a variety of microbial pathogens. First of all Orientia tsutsugamushi can invade a wide range of nonprofessional phagocytic cells including fibroblast, epithelial cells and endothelial cells of various host species, including Band T lymphocytes. Thus, it was postulated that the attachment of O. tsutsugamushi requires the recognition of ubiquitous surface structures of many kinds of host cells. Treatments with heparan sulfate and heparin inhibited the infection of Orientia tsutsugamushi in dose-dependent manner for L cell, mouse fibroblast, whereas other glycosaminoglycans such as chondroitin sulfate had no effect. Collectively, these findings provide strong evidence that initial interaction with heparan sulfate proteoglycan is required for the oriential invasion into host cells.

• Journal of Microbiology and Biotechnology
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• v.22 no.9
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• pp.1288-1295
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• 2012

Exposure to bioaerosols causes various adverse health effects including infectious and respiratory diseases, and hypersensitivity. Controlling exposure to bioaerosols is important for disease control and prevention. In this study, we evaluated the efficacies of various functional filters coated with antimicrobial chemicals in deactivating representative microorganisms on filters or as bioaerosols. Tested functional filters were coated with different chemicals that included (i) Ginkgo and sumac, (ii) Ag-apatite and guanidine phosphate, (iii) $SiO_2$, ZnO, and $Al_2O_3$, and (iv) zeolite. To evaluate the filters, we used a model ventilation system (1) to evaluate the removal efficiency of bacteria (Escherichia coli and Legionella pneumophila), bacterial spores (Bacillus subtilis spore), and viruses (MS2 bacteriophage) on various functional filters, and (2) to characterize the removal efficiency of these bioaerosols. All experiments were performed at a constant temperature of $25^{\circ}C$ and humidity of 50%. Most bacteria (excluding B. subtilis) rapidly decreased on the functional filter. Therefore, we confirmed that functional filters have antimicrobial effects. Additionally, we evaluated the removal efficiency of various bioaerosols by these filters. We used a six-jet collision nebulizer to generate microbial aerosols and introduced it into the environmental chamber. We then measured the removal efficiency of functional filters with and without a medium-efficiency filter. Most bioaerosol concentrations did not significantly decrease by the functional filter only but decreased by a combination of functional and medium-efficiency filter. In conclusion, functional filters could facilitate biological removal of various bioaerosols, but physical removal of these by functional was minimal. Proper use of chemical-coated filter materials could reduce exposure to these agents.

• Korean journal of applied entomology
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• v.58 no.4
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• pp.283-289
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• 2019

Overuse of antibiotics has significantly contributed to an increase in microbial antibiotic resistance, causing difficulties in the suppression of microbe-borne infectious diseases. In this study, we determined the anti-Klebsiella pneumoniae effect in the kidneys of mice induced by peptides isolated from H. illucens larvae. Mice were intranasally infected with a high dose of K. pneumoniae and 1 day later, peptides were introduced through the intramuscular route. Mice were sacrificed on day 10 upon K. pneumoniae infection to determine the bacterial loads in the kidneys. Mice receiving peptide treatment demonstrated significantly reduced bacterial loads, reduced bodyweight loss, and higher survival in a dose-dependent manner compared to control. These results indicate that peptide isolated from H. illucens larva inhibits K. pneumoniae infection in the kidney. The peptide from H. illucens larva could be a potential candidate for the development of an effective antibacterial drug.