• ALGAE
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• v.28 no.4
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• pp.297-305
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• 2013

There is increasing interest in the relationships between marine bacteria and red tide organisms. Some bacteria are known to kill red tide organisms, and may be responsible for accelerating the termination of red tides. Thus, certain algicidal bacteria have been proposed for the control of red tides. Meanwhile, many red tide organisms are known to feed on marine bacteria. The roles of marine bacteria and red tide organisms are therefore reversible. In Korean waters, the killing of red tide organisms by algicidal bacteria, and also the feeding of red tide organisms on marine bacteria have been extensively investigated. The findings of such studies may influence the conventional view of red tide dynamics, and also planktonic food webs. Here, we review the species and concentrations of algicidal bacteria that kill red tide organisms in Korean waters, as well as the ingestion rate and grazing impact of red tide organisms on marine bacteria. Furthermore, we offer an insight into the ecological roles of these 2 components in marine planktonic food webs.

• Journal of Embryo Transfer
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• v.1 no.1
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• pp.16-27
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• 1986

Based on the current importing and exporing regulations for disease control of embryo transfer, some important microorganisms and their control possibilities are reviewed. The results reviewed were sumrnarized as follows: 1. Regulations regarding to the import of embryos vary between importing and exporting countries, but exporting countries examine the donor and embryos for the heaith certification by the requirements of importing countries. 2. Organisms that infect the gametes are 5 kinds of viruses and the diseases caused by them could not be controlled or eradicated using embryo transfer. 3. Organisms that do not infect the gametes are 4 kinds of viruses and the causal organisms are potential candidates for control or eradication by embryo transfer. 4. Organisms that penetrate the zona pellucida and infect the embryo are 6 kinds of viruses including bovine viral diarrhea virus. 5. Organisms that cannot penetrate the zona pellucida or do not infect the embryo are 15 kinds of viruses and the removal from their contaminations are recommended by proper washing procedure and antisera treatment. Bovine and porcine parvovirus, porcine pseudorabies virus and vesicular stomatitis virus are included in these organisms. 6. Bovine embryos that artificially exposed to various pathogenic organisms such as bovine herpes virus, IBR virus, bluetongue virus, bovine viral diarrhea virus and Brucella abortus in vitro are discussed about their infection by several treatments.

• Fisheries and Aquatic Sciences
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• v.20 no.1
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• pp.1.1-1.7
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• 2017

A survey was conducted to investigate the presence of epiphytic organisms in four kelp Saccharina japonica farms in the coastal area of Korea from 2014 to 2015. Of 740 kelp samples that were taken, 208 exhibited six kinds of epiphytic organisms, including hydroid (detection rate: 11.6%), bryozoan (6.4%), polychaete (3.4%), algae (3.2%), caprellid (3%), and oyster (0.5%). The infestation rate for hydroid, bryozoan, and polychaete was significantly higher in the Wando farm, Busan farm, and Pohang farm, respectively. Epiphytic organisms were generally observed during May to September and not January to April, indicating that their infestation was significantly higher when the water had a higher temperature. The histopathogical examination revealed that hydroid and bryozoan organisms were attached on the cuticula of the thallus while some algae were attached on the cuticula of the thallus or had penetrated the epidermis. These results indicate that hydroid and bryozoan were the most predominant epiphytic organisms in Korean kelp farms, even though the infested thallus had not been broken.

• Journal of Marine Life Science
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• v.7 no.2
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• pp.154-162
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• 2022

In this study, data on the types and density of abalone attached organisms were provided in marine net cage of the southern coast. In addition, the effect of the removal of attached organisms was evaluated. In marine net cage, oysters, bryozoa, and barnacles were dominated among the attached organisms, and their average area ratio was about 57.5%. The growth rate and hepatopancreas condition were better in removal group of attached organisms than control group. Therefore, it is judged that the removal of attached organisms from abalone is necessary for the growth of individuals and improvement of value.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 2000.04a
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• pp.142-149
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• 2000

Recent molecular and polyphasic taxonomic approaches toward bacterial systematics have played a significant role in revolutionizing our insight in the taxonomy of bacterial organisms. This advance has also contributed greatly to delineation of new taxa from bacterial organisms isolated from a variety of natural sources of Korea. Recently, many bacterial organisms have isolated from soil, seawater, foods, wastewaters and humans of Korea and have been subjected to polyphasic taxonomic study. From the results of this study, some isolates have been found to be members of new genera and new species.

• Ocean and Polar Research
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• v.29 no.3
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• pp.263-271
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• 2007

The survival strategies of polar organisms at permanently or extremely cold temperatures and their application to cryobiology were reviewed here. In addition, ongoing studies on psychrophiles also were described. Psychrophiles are extremophiles that can grow and reproduce in cold temperatures, typically at -10 to $20^{\circ}C$. These organisms developed various mechanisms of adaptation to extremely cold environments. Polar organisms cope with these extreme physicochemical conditions using strategies such as avoidance, protection and partnership with other organisms. Understanding on the strategies adopted by polar organisms may provide insight on the physiological process that cells can go through during freezing. Cryopreservation may be able to take advantage of the findings described above. Currently, genomes of many cold-loving organisms have been sequenced and comparative genomics has revealed, at a molecular level, the characteristics of these organisms. The investigation of microorganisms on the polar glaciers may expand our understanding on the origin of life on Earth and other planets.

• Journal of Microbiology and Biotechnology
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• v.25 no.10
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• pp.1621-1628
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• 2015

Chlamydia possesses a conserved 7.5 kb plasmid that is known to play an important role in chlamydial pathogenesis, since some chlamydial organisms lacking the plasmid are attenuated. The chlamydial transformation system developed recently required the use of plasmid-free organisms. Thus, the generation and identification of plasmid-free organisms represent a key step in understanding chlamydial pathogenic mechanisms. A tricolor immunofluorescence assay for simultaneously detecting the plasmid-encoded Pgp3 and whole organisms plus DNA staining was used to screen C. muridarum organisms selected with novobiocin. PCR was used to detect the plasmid genes. Next-generation sequencing was then used to sequence the genomes of plasmid-free C. muridarum candidates and the parental C. muridarum Nigg strain. We generated five independent clones of plasmid-free C. muridarum organisms by using a combination of novobiocin treatment and screening plaque-purified clones with anti-Pgp3 antibody. The clones were confirmed to lack plasmid genes by PCR analysis. No GlgA protein or glycogen accumulation was detected in cells infected with the plasmid-free clones. More importantly, whole-genome sequencing characterization of the plasmid-free C. muridarum organism and the parental C. muridarum Nigg strain revealed no additional mutations other than loss of the plasmid in the plasmid-free C. muridarum organism. Thus, the Pgp3-based immunofluorescence assay has allowed us to identify authentic plasmid-free organisms that are useful for further investigating chlamydial pathogenic mechanisms.

• Korean Journal of Pharmacognosy
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• v.21 no.1
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• pp.1-48
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• 1990

Marine organisms have proven to be rich sources of interesting organic molecules. A great number of compounds with diverse structural features and interesting biological activities have been isolated. Recent studies on secondary metabolites of marine organisms are discussed with a focus on a variety of biological activities and marine natural product literatures are also reviewed.

• Natural Product Sciences
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• v.9 no.3
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• pp.117-142
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• 2003

The sphingolipids isolated from marine organisms and their biological activities have been reviewed.

• Proceedings of the Korean Aquaculture Society Conference
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• 2005.05a
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• pp.80-81
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• 2005

To investigate the food organisms of the Acanthogobius hasta 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 A. hasta was 5.5 mm ${\sim}$ 8.9 mm size, and the participation rate of feeding was 69.6%. 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 62.7%, and next, food organisms appeared much by order of decapods, polychaete larvae and amphipods etc.. Therefore, most important food organisms of juvenile stage of A. hasta were copepods, decapods, polychaete larvae, amphipods etc.