• 한국수산과학회지
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• 제54권5호
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• pp.808-813
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• 2021

The diet composition of Spanish mackerel Scomberomorus niphonius, was investigated using 853 specimens collected using two-boat trawl, stow net, gill net and set net from January to December 2019 from the South Sea of Korea. The size of the specimens ranged from 25.2 to 114.8 cm in fork length. S. niphonius fed mostly on fishes. Its diets also included small quantities of shrimps, cephalopods, crabs, stomatopods, etc. Among them, Engraulis japonicus was the dominant species. The dietary composition of S. niphonius exhibited significant differences based on their size. The proportion of Trichiurus japonicus increased as body size of S. niphonius increased, whereas the proportion of E. japonicus decreased gradually. As the body size of S. niphonius increased, the mean weight of prey per the stomach (mW/ST) tended to increase significantly (one-way ANOVA, P<0.05).

• Mycobiology
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• 제49권2호
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• pp.151-160
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• 2021

Despite recent studies, relatively few are known about the diversity of fungal communities in the deep Atlantic Ocean. In this study, we investigated the diversity of fungal communities in 15 different deep-sea sediments from the South Atlantic Ocean with a culture-dependent approach followed by phylogenetic analysis of ITS sequences. A total of 29 fungal strains were isolated from the 15 deep-sea sediments. These strains belong to four fungal genera, including Aspergillus, Cladosporium, Penicillium, and Alternaria. Penicillium, accounting for 44.8% of the total fungal isolates, was a dominant genus. The antiaflatoxigenic activity of these deep-sea fungal isolates was studied. Surprisingly, most of the strains showed moderate to strong antiaflatoxigenic activity. Four isolates, belonging to species of Penicillium polonicum, Penicillium chrysogenum, Aspergillus versicolor, and Cladosporium cladosporioides, could completely inhibit not only the mycelial growth of Aspergillus parasiticus mutant strain NFRI-95, but also the aflatoxin production. To our knowledge, this is the first report to investigate the antiaflatoxigenic activity of culturable deep-sea fungi. Our results provide new insights into the community composition of fungi in the deep South Atlantic Ocean. The high proportion of strains that displayed antiaflatoxigenic activity demonstrates that deep-sea fungi from the Atlantic Ocean are valuable resources for mining bioactive compounds.

• Ocean and Polar Research
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• 제43권1호
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• pp.31-43
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• 2021

To understand the temporal variation of prokaryotic communities in a temperate coastal area, prokaryotic abundance, activity, and community composition were investigated every week for over a year at a coastal monitoring station of Yeong-do, Busan. The prokaryotic abundances fluctuated about 10 times, ranging from 2.0 to 20.1 × 10⁵ cells mL^-1 and tended to be high in spring when phytoplankton bloom occurred. The prokaryotic thymidine incorporation rates (TTI) varied in a low range between 0.2 and 11.5 pmol L^-1 h^-1 in winter. However, in summer, TTI were increased up to a range of 8.3 to 17.4 pmol L^-1 h^-1, showing an increasing pattern in summer. During the study period, Alphaproteobacteria was the most dominant class for most of the year, followed by Flavobacteria. While the seasonal variation of prokaryotic composition was not apparent at the class level, many prokaryotic species showed a distinct temporal or seasonal variation for the year. In the coastal site, prokaryotic biomass and activity did not show significant correlations with temperature and chlorophyll-a, which are well known to regulate prokaryotic growth in marine environments, suggesting that the study area may be affected by diverse sources of organic matter for their growth.

• 환경생물
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• 제39권1호
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• pp.81-87
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• 2021

2008년 4월부터 2009년 3월까지 1년간 우리나라 서남해안 함평만의 도리포에서는 조간대의 해조류 식물 군집과 가입리에서는 식용 해조류 가시파래의 월별 변동성을 매월 조사하였다. 조사된 해조류는 총 22종이었으며, 녹조류 5종, 갈조류 4종 그리고 홍조류 13종이었다. 함평만 도리포 암반 조간대에서 연간 우점하는 해조류는 구멍갈파래였고, 준 우점종은 잎파래와 애기가시덤불이었다. 조간대 상부에서 하부에 이르는 수직분포는 잎파래 - 애기가시덤불 - 구멍갈파래 - 지충이었다. 가시파래의 생물량은 6월에 최대를 보였고 11월에 최소를 보였으며, 2.4-98.2 g dry wt. m^-2 범위를 나타냈다. 가시파래의 생물량은 수온과 연관이 있어 보이지만 영양염류 및 빛의 강도 같은 기타 환경요인과의 관계는 추후 지속적인 연구가 요구된다.

• 한국식품과학회지
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• 제54권3호
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• pp.343-350
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• 2022

밀누룩과 탁주의 미생물 군집을 NGS로 분석하여 탁주의 이상 발효 원인을 규명하였다. 우점도가 높은 미생물은 알코올 발효 이후 변화하여, 누룩에서는 Aspergillus 속 곰팡이와 Staphylococcus 속 세균이 우세하였고, 탁주에서는 Saccharomyces 속 효모와 Pediococcus, Bacillus, Lactobacillus, Enterobacter 속 세균이 우세하였다. 특이적으로 본 연구에서 분석된 누룩과 탁주 시료는 유산균의 함량이 상대적으로 낮았다. 이러한 미생물학적 환경에서 Bacillus 속과 Enterobacter 속이 기회 감염균인 Bacillus wiedmannii와 Enterobacter cloacae로 확인되었고, B. wiedmannii와 E. cloacae는 각각 유기산의 농도가 급격히 감소한 밑술 발효 3일과 원료가 첨가된 덧술 발효 1일에서부터 점차적으로 증가하였다. 이를 통해 탁주의 미생물은 누룩을 포함한 원료 및 발효 조건에 영향을 받으며, 유산균의 부재가 탁주에서 E. cloacae와 B. wiedmannii의 이상 증식에 영향을 주었다고 보여진다. 결론적으로 NGS를 통한 미생물 군집 분석은 누룩과 탁주의 미생물 구성과 발효 특성을 포괄적으로 이해하는데 도움을 주며, 더 나아가 전통누룩의 발효 조건 개선 및 고품질 전통주 생산에 활용할 수 있을 것으로 기대한다.

• International Journal of Industrial Entomology and Biomaterials
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• 제45권2호
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• pp.115-125
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• 2022

In this study, we investigated the developmental characteristics and genetic diversity of seven populations of two-spotted crickets (Gryllus bimaculatus De Geer, 1773 (Orthoptera: Gryllidae)) raised in South Korea. Regarding the developmental characteristics of the species, we observed no statistically significant difference in the weight of the nymphs in the six populations we tested. After molting, although weight differences were observed between the populations in each stage of the developmental period, the average weight for each developmental stage was constant. We also analyzed mitochondrial COI gene sequences (DNA barcoding region) of the reared crickets collected from five insect farms and two national insect rearing facilities and the resultant sequences were analyzed together with the 12 sequences from foreign countries specimens obtained from public data. We detected six haplotypes from 111 specimens, indicating a low intraspecific genetic distance (~1.8%). The most dominant haplotype was overwhelmingly haplotype 1, which was found in all South Korean specimens and four specimens from China, Indonesia, and Germany. These findings indicate that the low genetic diversity of South Korean specimens can be explained by the fact that the G. bimaculatus population imported for feed from Japan in the early 2000s became a maternal group that spread throughout cricket farms in South Korea. In order to breed healthy cricket strains, it is necessary to increase genetic diversity by importing them from other countries through appropriate quarantine procedures.

• Journal of Animal Science and Technology
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• 제64권5호
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• pp.897-910
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• 2022

Bovine fecal microbiota is important for host health and its composition can be affected by various factors, such as diet, age, species, breed, regions, and environments. The objective of this study was to evaluate the impact of diet and gender on fecal microbiota in Korean native Hanwoo cattle. The 16S rRNA gene amplicon sequencing of fecal microbiota was conducted from 44 Hanwoo cattle divided into four groups: (1) 11 heifers fed an oat hay plus total mixed ration (TMR) diet for breeding (HOTB), (2) 11 heifers fed an early fattening TMR diet (HEFT), (3) 11 steers fed the early fattening TMR diet (SEFT), and (4) 11 steers fed the late fattening TMR diet (SLFT). Firmicutes and Bacteroidota were the first and second most dominant phyla in all the samples, respectively. The Firmicutes/Bacteroidota (F/B) ratio associated with feed efficiency was significantly greater in the SLFT group than in the other groups. At the genus level, Romboutsia, Paeniclostridium, and Turicibacter were the most abundant in the SLFT while Akkermansia, Bacteroides, and Monoglobus were the most abundant in the HOTB group. Although the same early fattening TMR diet was fed to Hanwoo heifers and steers, Marvinbryantia and Coprococcus were the most abundant in the HEFT group while Alistipes and Ruminococcus were the most abundant in the SEFT group. Shannon and Simpson diversity indices were significantly lower in the SLFT group than in the other groups. Distribution of fecal microbiota and functional genetic profiles were significantly different among the four treatment groups. The present study demonstrates that different diets and genders can affect fecal microbiota and the F/B ratio may be associated with feed efficiency in Hanwoo cattle. Our results may help develop strategies to improve gut health and productivity through manipulation of fecal microbiota using the appropriate diet considering Hanwoo cattle gender.

• International Journal of Oral Biology
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• 제47권3호
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• pp.41-48
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• 2022

Ulva compressa Linnaeus (UCL) is a green algae seaweed that performs photosynthesis and is used as a food material in some Asian regions including Korea. It is known to be the dominant species in copper ion-contaminated seas, and many studies on copper ion resistant mechanisms have been reported. UCL is known to have an excellent antioxidant effect, but limited information is available regarding its other physiological activities. In this study, we investigated the anticancer activity of 30% prethanol extracts of Ulva compressa Linnaeus (30% PeUCL) and the underlying mechanisms of its activity on human FaDu hypopharyngeal squamous carcinoma cells. The 30% PeUCL extracts suppressed FaDu cell viability without affecting normal cells (L929), as determined by MTT and viability assays. Furthermore, the 30% PeUCL extracts induced apoptosis, as determined by DAPI staining. The 30% PeUCL extracts inhibited colony formation effectively as well as wound-healing of FaDu cells, even at noncytotoxic concentrations. In addition, 30% PeUCL extracts induced apoptosis significantly through proteolytic cleavage of caspase-3, -7, and -9, and poly (ADP-ribose) polymerase, and by downregulation of Bcl-2 and upregulation of Bax in FaDu cells, as determined by Western blot analysis. Collectively, these results suggest that the inhibitory effect of 30% PeUCL extracts on the growth of oral cancer cells, colony formation and wound-healing may be mediated by caspase- and mitochondrial-dependent apoptotic pathways in human FaDu hypopharyngeal squamous carcinoma cells. Therefore, 30% PeUCL extracts can be administered as a natural chemotherapeutic drug for the treatment of human oral cancers.

• 농촌의학ㆍ지역보건
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• 제47권2호
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• pp.61-66
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• 2022

Objectives: In the epidemiology of communicable diseases, the term epidemic period, also referred to as "wave" is often used in the general and academic milieu. A wave refers to a natural pattern of increase in the number of sick individuals, a defined peak, and then a decline in the number of cases. It implies a pattern of peaks and valleys after a particular peak is taken. The idea of epidemic waves is a useful tool for predicting the course as well as helping to accurately describe an epidemic. However, in many domestic and foreign news as well as in various research results in Korea, most of the reports either had no standard, were inaccurate, had a questionable classification of the period of the epidemic, or the basis for classification of a given wave was not presented. Methods: The author reviewed and organized related literature with epidemic wave. The author made several suggestions of an epidemic wave as follows. Results: To start with, it should be based on the number of incident cases in consideration of the size of the outbreak, then the period from the bottom to the peak and then reaching the next bottom; also, the period over a certain scale based on the number of incident cases; and the period according to the change in the major infection type (mutation-dominant species). In addition, according to the period of change in the vaccination rate (formation of herd immunity), as well as the content and duration of the intervention, that is, classification according to the applied quarantine stage. Furthermore, the classification of epidemic periods by the time-dependent reproduction number or time-varying reproduction number (Rt), and lastly the application of mathematical methodology. Conclusions: Therefore, classifying the epidemic period into generally known and accepted time frames is considered to be a very important task for future research analysis and development of intervention strategies.

• Parasites, Hosts and Diseases
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• 제61권3호
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• pp.304-309
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• 2023

Intestinal parasitic infections are a public health burden and a major cause of illness in developing countries. The diseases lead to various health threats, including growth retardation and mental health-related disorders, especially in children. We assessed the risk factors for intestinal parasitic infections among children aged 12-59 months residing in Nyamasheke District, Rwanda. A cross-sectional descriptive study was conducted using secondary data from 1,048 children aged 12-59 months whose stool samples were examined for the presence of intestinal parasites and whose results were registered in the laboratory information system in 2020. The prevalence of intestinal parasites in children aged 12-59 months was 53.2%. The dominant parasites were Ascaris lumbricoides (13.1%), followed by Giardia lamblia (10.9%), Entamoeba histolytica (7.9%), Trichuris trichiura (6.5%), hookworms (1.7%), and Taenia species (1.4%). A significant association was observed between intestinal parasites and the literacy of mothers or children's caregivers (odds ratio (OR)=5.09, P<0.001). Children from farming households were 2.8-fold more likely to contract intestinal parasitic infections than those from nonfarming households (OR=2.8, P<0.001). A significant association was also observed between intestinal parasites and food safety (OR=4.9, P<0.001). Intestinal parasitic infections were significantly associated with hand hygiene practices after using the toilet and washing fresh fruits before eating (P<0.001). The information gathered will help public health providers and partners develop control plans in highly endemic areas in Rwanda.