• Proceedings of the Korean Aquaculture Society Conference
• /
• 2005.05a
• /
• pp.82-83
• /
• 2005

To investigate the food organisms of the Chaenogobius mororanus during the juveniles stage, the stomach contents of fish, captured in the intertidal zone of Chungchong- nam-do Sochon-gun Su-myon Dodun-ri (Fig. 1) between on early June from end of May 2003, were observed. Total length of the juveniles of C. mororanus was 5.0 mm ${\sim}$ 8.4 mm size, and the participation rate of feeding was 71.4%. Main food organisms were such as copepods, decapods, polychaete larvae, amphipods and these occupied more than dry weight 3.9%. Copepods among them dominated the most quantitys by average 62.0%, and next, food organisms appeared much by order of decapods, polychaete larvae and amphipods etc.. Therefore, most important food organisms of juvenile stage of C. mororanus were copepods, decapods, polychaete larvae, amphipods etc.

• Asian-Australasian Journal of Animal Sciences
• /
• v.4 no.2
• /
• pp.161-164
• /
• 1991

A rapid and accurate method is described for the determination of nucleo-bases in rumen micro-organisms. A procedure to satisfactorily hydrolyse the micro-organisms involving reaction with a mixture of readily volatile organic acids (acetic and formic acids) under high pressure, is proposed, and optimal conditions for an analytical procedure with reversed phase HPLC is described. The following nucleobases contents (mmol/kg DM) of rumen micro-organisms were found: Adenine (Ade), 82.62; Guanine (Gua), 61.34; Cytosine (Cyt), 84.61; Thymine (Thy), 35.74; Uracil (Ura), 68.62; Hypoxanthine (Hxn), 13.06; Xanthine (Xn), 8.35. Total purine-N content (g/kg N) of rumen micro-organisms were 99.60. The nucleic acid N content (g/kg N) of microbial isolates were: RNA-N, 109.9; DNA-N, 50.9.

• Journal of Marine Bioscience and Biotechnology
• /
• v.2 no.2
• /
• pp.73-76
• /
• 2007

A large number of natural products were worldwidely discovered from maine organisms. There are many secondary metabolites produced by maine organisms which showed very strong bio-activities and distinct bio-active mechanisms. In korea, about 350 secondary metabolites including more than 280 novel compounds have been isolated and structually defined. Many researches for developing products such as cosmetics, functional food materials, anti-fouling substances are being performed using distinct activities of marine organisms. Although the research on marine natural products has been remained at its initial or developing stage of drug development, significant progress has been made for isolation, structure determination and bioassay of secondary metabolites.

• Parasites, Hosts and Diseases
• /
• v.38 no.3
• /
• pp.173-175
• /
• 2000

The present study examined postmetacercarial changes in the excysted metacercariae of Echinostoma caproni maintained in the defined medium Mixture 199 plus 20% calf serum for 7 days at $41^{\circ}C$. The gas phase was atmospheric air. Each culture was inoculated with 25 excysted metacerariae. Cultures were maintained upright in closed 15 ml plastic centrifuge tubes each containing 10 ml of medium plus 200 units of penicillin/ml and $200{\;}\mu\textrm{g}$ of streptomycin/ml. By 4 days in culture, most metacercariae had voided their excretory concretions. Organisms were clumped or solitary at the bottom of the cultures. Many organisms showed flaring of the oral collar and extension of both the collar and tegumentary spines. By 4 days in culture, posterior protuberances or bumps were noted on many of the organisms and some organisms showed abnormal vesicular growths or blebs at their posterior ends. Some mortality was noted in culture by day 5, but most organisms were still alive when the cultures were terminated on day 7.

• Journal of Ecology and Environment
• /
• v.37 no.4
• /
• pp.185-194
• /
• 2014

Seasonal monitoring was implemented to understand the influence of macrophyte bed structure on the composition and trophic interaction of aquatic organisms (algae, zooplankton, macro-invertebrate, and fish) in a shallow wetland (Upo Wetland, South Korea). Distinct division of the plant assemblage (reed zone and mixed plant zone) was observed. The reed zone was composed solely of Phragmites communis, whereas the mixed plant zone comprised a diverse macrophyte assemblage (Salvinia natans, Spirodela polyrhiza, Trapa japonica, Ceratophyllum demersum, and Hydrilla verticillata). Most of the aquatic organisms were more abundant in the mixed plant zone than in the reed zone, and this was positively associated with the seasonal development of macrophyte cover. Stable isotope analysis showed seasonal interactions among aquatic organisms. The majority of aquatic animal (zooplankton, Odonata, and Ephemeroptera) were dependent on epiphytic particulate organic matter (EPOM), and the dependence on EPOM gradually increased toward autumn. Interestingly, Lepomis macrochirus consumed Ephemeroptera and zooplankton in both macrophyte zones, but Micropterus salmoides depended on different food items in the reed zone and the mixed plant zone. Although, M. salmoides in the reed zone showed food utilization similar to L. macrochirus, it consumed Odonata or small L. macrochirus in the mixed plant zone. Based on these results, it appears that differences in the structure of the two macrophyte zones support different assemblages of aquatic organisms, strongly influencing the trophic interactions between the aquatic organisms.

• Journal of Korean Society on Water Environment
• /
• v.29 no.4
• /
• pp.459-465
• /
• 2013

A sequencing batch reactor was operated under different pH conditions to see the influence of pH to microbial community in enhanced biological phosphorus removal (EBPR) systems. Long term influences of different steady-state pH conditions on the microbial community composition were evaluated by polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE) and fluorescence in situ hybridization (FISH). The shift in populations from polyphosphate-accumulating organisms (PAOs) to Alphaproteobacteria was observed when pH was changed from 7.5 to 7.0. Alphaproteobacteria with the typical morphological traits of tetrad-forming organisms (TFOs) eventually became dominant members. The alphaproteobacterial TFOs were the phenotype expected for glycogen-accumulating organisms (GAOs), which accumulate large amount of glycogen into the cell. The results strongly suggested that low operational pH condition encourages the appearance of the GAOs in EBPR process, significantly reducing the EBPR capacity.

• Proceedings of the Korea Society of Environmental Toocicology Conference
• /
• 1993.06a
• /
• pp.4-5
• /
• 1993

Toxicity tests in our laboratory are conducted usually with mass-reared organisms. They are under the same environmentel conditions throughout seasons and are supplied at specific age. A total of 38 species of aquatic organisms are being reared. We have attempted to establish pruified strains or to select clones of various parthenogenic organisms. The merits or demerits of our culturing test organisms are discussed. The differences in the susceptibility among clones or strains of test organism are also discussed. For a single species test, algae, daphnia, fish are often used. However, we usually use early stages, but occasionally, adults fish are used for reproduction tests. As an another important aspect, the toxicity through food chains has been studied. In this study, we select a pair of species belonging different trophic levels. The differences between single species tests and multispecies tests will be discussed. Even a single species test intends to assess the effects of chemicals on ecosystem levels, however, this idea is not applicable to ecosystems. Single species tests with standard organisms and multispecies tests are contradictory in concept. One type of multispecles tests is indoor microcosms being composed of severel species artificially assembled, and another is composed of natural components (both indoor and outdoor). We have used three types of outdoor mesocosms using ponds and three types of artificial streams. The mesocosms is useful to not only to analyze the floral or faun61 changes but also to study the fate or behaviour of chemicals in naturd environments. Lastly, usefulness of the field observation or experiments or semi-field experiments will be discussed. This will enhance the exploitation of early warning systems utilizing indicator organisms or animal behaviour.aviour.

• Fisheries and Aquatic Sciences
• /
• v.7 no.3
• /
• pp.141-147
• /
• 2004

Sixteen polycyclic aromatic hydrocarbons (PAHs) were analyzed in seventy marine organisms (40 species) from the Korean coast. PAHs were present in all the organisms. The level of total PAHs in the organisms varied from 0.45 to 224 ng/g dry weight and the carcinogenic PAHs varied from 0.05 to 49.8 ng/g dry weight. The PAHs residues according to the marine organisms showed a highest content in bivalve species, and followed by crustaceans, cephalopods, fish and gastropods. Human dietary intake of total PAHs through marine organism in Korea was estimated to be 4.12 ng/kg body weight/day and 0.67 ng/kg body weight/day for carcinogenic PAHs. The relative contributions of individual species to the total dietary intake of PAHs were in the order of bivalves $(53.4{\%})$, fish $(21.9{\%})$, crustaceans $(15.3{\%})$, cephalopods $(8.8{\%})$ and gastropods $(0.6{\%})$. Daily dietary intake of $PAH_{TEQ}$ expressed as a TEQ value was estimated to be 0.13 pg TEQ/kg body weight/day, which did not exceed a tolerable daily intake (TDI) proposed by the KFDA and the WHO as well as the UK toxicity committee. Lifetime cancer risk due to ingestion of marine species by the Korean adult was evaluated using the equation estimating exposure of food ingestion. Although approximately $23{\%}$ of cumulative frequency of the sampled marine species exceeded the cancer risk guideline, lifetime cancer risk associated with marine organism consumption was negligible. Results indicate that dietary intake of PAHs through the consumption of the Korean marine organisms seems to be safe for human ingestion with negligible cancer risk.

• Korean Journal of Veterinary Research
• /
• v.14 no.2
• /
• pp.243-252
• /
• 1974

The experiment was performed in order to investigate the applicability of the rapid detection of salmonellae in various animal-origin foods by means of the direct fluorescent antibody technique. Egg, sausage and chicken were inoculated with various concentrations of Sal.paratuphi A, Sal. paratyhi B and Sal. thompson, and the fluorescent antibody technique was applied and compared with the conventional cultura method for the sensitivity of detection of the organisms. Two methods were employed in the fluorescent antibody technique; the direct smear method in which the smear being made directly from the specimens, and the enrichment smear method in which the smear being made from the enrichment broth. The effect of various enrichment time (1,5,8,11 and 13 hours) in tetrathionate broth on the detection of salmonellae in the fluoresent antibody technique was also studied. The results obtained were summarized as followings; 1. Of the three methods, the enrichment smear method of fluorescedt antibody technique was highly effective as cultural method for the detection of salmonella organisms. 2. Direct smear method of fluorescent antibody technique was effective as two other methods $5{\times}10^4$ organisms presented in 50 g(ml) of specimens. This method may not be applicable when the specimens contained $5{\times}10^2$ or less organisms. 3. Of the three specimens, the recovery rate of Salmonella organisms from egg was slightly higher than that of sausage and chicken. 4. In fluorescent antibody technique and cultural method, the specimens inoculated with Sal. thompson were found to be higher detection rate than the specimens inoculated with Sal. paratyphi A, 5. The optimum enrichment time of Salmonella organisms in tetrathionate broth on the detection by fluorscent antibody technique was found to be 11 hours or longer when the specimens of egg, sausage and chicken were inoculated with approximately 500 organisms. The longer enrichment time was the higher detection rate up to 11 hours tested.

• Journal of Home Health Care Nursing
• /
• v.27 no.3
• /
• pp.321-329
• /
• 2020

Purpose: This study was conducted to assess the factors that affect the confidence of nurses at small and medium-sized hospitals in the control of infections caused by multidrug-resistant organisms and to establish basic data for the interventional strategy to improve the nurses' execution of the control of infection caused by multidrug-resistant organisms. Methods: A total of 154 nurses working at four small and medium-sized hospitals situated in City C were selected as participants of this study. Data were collected using a structured questionnaire and analyzed using the IBM SPSS 21.0 software. Results: Confidence in controlling infections caused by multdrug-resistant organisms had a positive correlation with the level of knowledge of this control and the health beliefs of the nurses. Factors that affect nurses' confidence in controlling infections caused by multidrug-resistant organisms included perceived benefits (β=.431, p<.001) and knowledge (β=.354, p<.001) with an explanatory power of 36.4%. Conclusion: It was found that the nurses have higher confidence in executing their duties with higher perceived benefits of and knowledge about the control of infections caused by multidrug-resistant organisms. As such, it is deemed necessary to establish strategies to elevate the advantages of and knowledge about infection prevention activities at the time of training/education on controlling infections caused by multidrug-resistant organisms.