• Membrane and Water Treatment
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• v.10 no.6
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• pp.395-404
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• 2019

The influence of chlorine on marine bacterial communities was examined in this study. A non-chlorine-adapted marine bacterial community (NCAM) and a chlorine-adapted bacterial community (CAM, bacterial community treated with $0.2mg-Cl_2/L$ chlorine) were cultivated for 1 month. A distinct difference was observed between the NCAM and CAM, which shared only eight operational taxonomic units (OTUs), corresponding to 13.1% of the total number of identified OTUs. This result suggested that chlorine was responsible for the changes in the marine bacterial communities. Kordiimonas aquimaris was found to be a chlorine-resistant marine bacterium. The effect of intermittent chlorination on the two marine biofilm communities formed on the reverse osmosis (RO) membrane surface was investigated using various chlorine concentrations (0, 0.2, 0.4, 0.6 and 0.8 mg $Cl_2/L$). Although the average number of adherent marine bacteria on the RO membrane over a period of 7 weeks decreased with increasing chlorine concentration, disinfection efficiencies showed substantial fluctuations throughout the experiment. This is due to chlorine depletion that occurs during intermittent chlorination. These results suggest that intermittent chlorination is not an effective disinfection strategy to control biofilm formation.

• Journal of Veterinary Science
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• v.22 no.3
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• pp.37.1-37.14
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• 2021

Background: Ticks are one of the most common external parasites in dogs, and are associated with the transmission of a number of major zoonoses, which result in serious harm to human health and even death. Also, the increasing number of pet dogs and pet owners in China has caused concern regarding human tick-borne illnesses. Accordingly, studies are needed to gain a complete understanding of the bacterial composition and diversity of the ticks that parasitize dogs. Objectives: To date, there have been relatively few reports on the analysis of the bacterial community structure and diversity in ticks that parasitize dogs. The objective of this study was to investigate the microbial composition and diversity of parasitic ticks of dogs, and assessed the effect of tick sex and geographical region on the bacterial composition in two tick genera collected from dogs in China. Methods: A total of 178 whole ticks were subjected to a 16S ribosomal RNA (rRNA) next generation sequencing analysis. The Illumina MiSeq platform targeting the V3-V4 region of the 16S rRNA gene was used to characterize the bacterial communities of the collected ticks. Sequence analysis and taxonomic assignment were performed using QIIME 2 and the GreenGene database, respectively. After clustering the sequences into taxonomic units, the sequences were quality-filtered and rarefied. Results: After pooling 24 tick samples, we identified a total of 2,081 operational taxonomic units, which were assigned to 23 phyla and 328 genera, revealing a diverse bacterial community profile. The high, moderate and low prevalent taxa include 46, 101, and 182 genera, respectively. Among them, dominant taxa include environmental bacterial genera, such as Psychrobacter and Burkholderia. Additionally, some known tick-associated endosymbionts were also detected, including Coxiella, Rickettsia, and Ricketssiella. Also, the potentially pathogenic genera Staphylococcus and Pseudomonas were detected in the tick pools. Moreover, our preliminary study found that the differences in microbial communities are more dependent on the sampling location than tick sex in the tick specimens collected from dogs. Conclusions: The findings of this study support the need for future research on the microbial population present in ticks collected from dogs in China.

• Korean Journal of Microbiology
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• v.28 no.3
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• pp.204-209
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• 1990

The total and heterotrophic bacterial distributions, compositions and alkaline phosphatese actibities were analyzed in Lake Soyang from Sep. 1987 to Aug. 1988. The heterotrophic bacteria was small portion, 0.07-2.63% of total bacterial number which ranged from $3.2{\times}10^{5}$ to $3.2{\times}10^{6}$ cells/${\mu}\ell$. The composition of bacterial community was less diverse in summer and at the fish farm site and Peridinium blooming site. Pseudomonas and Flavo bacterium were the dominant genera in all sites. The highest proportion and activity of alkaline phsophatase was appeared in Flavobacterium, while Pseudomonas was the most predominant group.

• Journal of Korean society of Dental Hygiene
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• v.24 no.2
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• pp.131-139
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• 2024

Objectives: Oral bacterial samples included subgingival, supragingival, and saliva plaques. As the diversity and number of microorganisms deffer depending on the area of the oral cavity and the method used, an appropriate and reliable collection method is important. The present study investigated oral bacterial sampling methods. Methods: Supragingival dental plaque was collected from the buccal and lingual tooth surfaces of study participants using sterilized cotton swabs. Plaques were collected from the subgingival area using a sterilized curette. Bacterial genomic DNA was extracted using MagNA Pure 96 DNA and Viral NA low-volume kits. Real-time polymerase chain reaction (PCR) was performed using the PowerCheck^TM Periodontitis Pathogens Multiplex Real-time PCR kit. Results: Aggregatibacter actinomycetemcomitans, Prevotella intermedia, and Fusobacterium nucleatum of the orange complex were not observed in the subgingival biofilms of all study participants. For Porphyromonas. gingivalis, a significant correlation was observed between supragingival, subgingival, and total tooth surface biofilms. Compared to the supragingival and subgingival biofilmss, total tooth surface biofilm exhibited the highest bacterial count when the inswabbing method was used. Conclusions: Based on these findings, the supragingival swab method is recommended for oral bacterial research.

• Journal of the East Asian Society of Dietary Life
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• v.10 no.5
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• pp.419-424
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• 2000

To develop a functional Kimchi utilizing onion, 5 different Kimchi with onion used as a major ingredient were formulated. The changes in pH. titratable acidity, reducing sugar. total bacterial count, and the number of lactic acid bacteria in the process of fermentation were studied A. onion Kimchi Control. B : onion Kimchi added with oyster, C : onion Kimchi added with salted shrimp, D : onion Kimchi added with oyster, cucumber, and a bit of radish, E : onion Kimchi added with salted shrimp, cucumber, and a bit of radish. pH of onion Kimchi decreased during storage, but titratable acidity increased. The pH values of onion Kimchi were not significantly different among groups, the changes in pH during fermentation were the lowest in A, and changes in B and D were lower than those of C and E. Salt concentration tended to decrease during the fermentation process, and the changes in salt concentration were lower in D and E than in B and C. Reducing sugar content maximized at 4 days of fermentation and decreased after 12 days. The number of lactic acid bacteria increased during first 4 days of fermentation and decreased after 12 days. Total lactic acid bacterial count were the most lowest in A.

• Korean Journal of Microbiology
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• v.27 no.3
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• pp.272-278
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• 1989

The bacteria utilizing 3-chlorobenzoate as a sole carbon and energy source were isolated by Most-Probable-Number technique and identified in Korean coastal waters. Pseudomonas, Moraxella and Flavobacterium were dominant genera and comprised 70.2% of total isolates. Forty-four biochemical, cultural, morphological and physiological testa were performed and average linding cluster analysis was conducted from the test results. Total 92.7% of isolates were clustered into 17 groups under the 80% similarity level. The degradation of 3-chlorobenzoate was performed by many heterogeneous bacteria and the species diversity of these bacterial group offers informations of the stability of bacterial communities in relation to carbon compound cycling in coastal enviromnents.

• Journal of Fisheries and Marine Sciences Education
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• v.24 no.4
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• pp.591-601
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• 2012

Olive flounders, Paralichthys olivaceus, were intraperitoneally challenged with Edwardsiella tarda or Streptococcus iniae or both bacteria simultaneously. The pathogenicity was respectively compared with blood chemical using alanine aminotransferase (ALT), aspatate aminotransferase (AST), glucose and total protein, lysozyme activity, bacterial number of kidney and spleen, histopathological change, and cumulative mortality. The tested group of coinfection showed increased cumulative mortality, bacterial number of kidney and spleen, AST and histopathological change, but not in lysozyme activity compared with others. This study provides support for the conclusion that simultaneous infection with Edwardsiella tarda and Streptococcus iniae in a susceptible host results in higher pathogenicity, leading to the increment of bacterial number and the destruction of the internal organs.

• Journal of Nutrition and Health
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• v.32 no.1
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• pp.64-64
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• 1999

The relations between micorfloral compositions and environmental factors of 32 Korean infants were sought through statistical analysis after examination of fecal bacterial and questions to their mothers about feeding experiences at three different times for each subjects, about one week after birth, before weaning (2-3 months after birth), and after weaning 95-7 months after birth). The majority of mothers fed their infants cereal foods after the age of 4 months and began weaning with fruit juice and commercial weaning foods. Defection frequencies and fecal pH of infants decreased significantly during the examination period and 37.5% of total infants in fecal samples increased significantly during the examination period, which means that the kinds of bacterial genera increase with aging of infants. Frequencies of streptococci were significantly higher in infants fed delivered by Caesarian section than infants delivered naturally. Frequencies of clostridia were significantly higher in infants fed with cereal food before 4 months of age than after 5 months. The infants fed with probiotics showed significantly higher frequencies of veillonella at about 1 week old. They also showed significantly higher frequencies of clostridia before weaning than the infant fed with no probiotics, but significantly lower frequencies of C. perfringens before weaning. The infants fed with probiotics showed significantly higher number of streptococci at the age of about 1 week and significantly higher numbers of total aerobes before weaning, but significantly lower numbers of bacteroides after weaning than their counter parts. The fecal pH was directly proportional to the number of clostridia, klebsiella, and total aerobes at about 1 week after birth, to the number of E. coli before weaning, and to the number of streptococci and clostridia after weaning. Fecal pH had a negative relationship to the total number of anaerobes in 1-week-old infants. The infants that had diarrhea during lactation showed higher frequencies of bacteroides before weaning than those that didn't.

• Journal of Nutrition and Health
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• v.32 no.1
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• pp.67-74
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• 1999

The relations between micorfloral compositions and environmental factors of 32 Korean infants were sought through statistical analysis after examinaton of fecal bacterial and questions to their mothers about feeding experiences at three different times for each subjects, about one week after birth, before weaning (2-3 months after birth), and after weaning 95-7 months after birth). The majority of mothers fed their infants cereal foods after the age of 4 months and began weaning with fruit juice and commercial weaning foods. Defection frequencies and fecal pH of infants decreased significantly during the examination period and 37.5% of total infants in fecal samples increased significantly during the examination period, which means that the kinds of bacterial genera increase with aging of infants. Frequencies of streptococci were significantly higher in infants fed delivered by Caesarian section than infants delived naturally. Frequencies of clostrida were significantly higher in infants fed with cerealfood before 4 months of age than after 5 months. The infants fed with probiotics showed significantly higher frequencies of veillonella at about 1 week old. They also showed significantly higher frequencies of clostridia before weaning than the infant fed with no probiotics, but significantly lower frequencise of C. perfringens before weaning. The infants fed with probiotics showed significantly higher number of streptococci at the age of about 1 week and significantly higher numbers of total aerobes before weaning, but significantly lower numbers of bacteroides after weaning than their counter parts. The fecla pH was directly proportional to the number of clostridia, klebsiella, and total aerobes at about 1 week after birth, to the number of E. coli before weaning, and to the number of streptococci and clostridia after weaning. Fecal pH had a negative relationship to the total number of anaerobes in 1-week-old infants. The infants that had diarrhea during lactation showed higher frequencies of bacteroides before weaning than those that didn't.

• Korean Journal of Veterinary Research
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• v.15 no.1
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• pp.83-91
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• 1975

A total of 119 raw milk samples from ten dairy farms were examined for total bacterial count, and 739 quarter milk samples of 118 dairy cows of 14 herds were examined for mastitis. The results obtained were as follows: 1. The mean of total bacterial counts of the 119 raw milk samples was 132,000 per ml. The total bacterial counts of 81 samples (68.1%) were under the standard of 100,000 per ml and those of the 38 samples (31. 9%) were over the standard. The number of bacteria showed a tendency to increase in summer. 2. One hundred and ninety five quarters (26.4%) of 98 cows (52.7%) were proved to be infected with mastitis. Clinical mastitis was found at 7 qtarters (3.5%) of 5 cows (5.0%). 3. Staphylococcus (44.9%) and Streptococcus (26.7%) were two main causative organisms of mastitis. Coliform bacteria (4.6%), Pseuedomonas spp. (4.6%), yeasts (1. 3%) and corynebacterium sp. (0.7%) were also isolated from the infected quarters. 4. The isolates were more sensitive to chloramphenicol ((96.1%), leukomycin (78.8%), streptomycin (75.5%) and tetracycline (72.4%). On the other hand, they were less sensitive to colistin (11.0%), oreandomycin (18.1%), sulfisoxazole (24.6%), penicilline (27.6%), kanamycin (43.3%) and erythromycin (49.7%). Especially the strains of Pseudomonas spp. isolated from the infected quarters were resistant to almost all the drugs examined.