• Microbiology and Biotechnology Letters
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• v.38 no.1
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• pp.19-23
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• 2010

Recently, marine organisms are emerging as a leading group for identifying and extracting novel bioactive substances. These substances are known to possess a potential regarding not only as a source of pharmaceutical products but also their beneficial effects on humans. Among the substances, antimicrobial peptides (AMPs) specifically have attracted considerable interest for possible use in the development of new antibiotics. AMPs are characterized by relatively short cationic peptides containing the ability to adopt a structure in which cationic or hydrophobic amino acids are spatially scattered. Although a few reports address novel marine organisms-derived AMPs, their antimicrobial mechanism(s) are still remain unknown. In this review, we summarized the peptides previously investigated, such as Pleurocidin, Urechistachykinins, Piscidins and Arenicin-1. These peptides exhibited significant antimicrobial activities against human microbial pathogens without remarkable hemolytic effects against human erythrocytes, and their mode of actions are based on permeabilization of the plasma membrane of the pathogen. Therefore, the study of antimicrobial peptides derived from marine organisms may prove to be useful in the design of future therapeutic antimicrobial drugs.

• Journal of The Korean Society of Clinical Toxicology
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• v.13 no.1
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• pp.40-42
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• 2015

Benzoylureas are chemical compounds best known for their use as insecticides. Diflubenzuron is one of the more commonly used benzoylurea pesticides. Others include chlorfluazuron, flufenoxuron, hexaflumuron, and triflumuron. They act as insect growth regulators by inhibiting synthesis of chitin in the body of the insect. They have low toxicity in mammals because mammals have no chitin. Chlorfluazuron insecticides, which are mixed with solvent naphatha, are commonly used. Thus we assume that in the presented case mental change outcome of poisoning was connected with toxic effects of solvent naphtha rather than with chlorfluazuron action. Components of solvent naphtha, particularly trimethylbenzenes, exert strong irritant action on the gastric mucosa and are very well absorbed from the gastrointestinal tract. We report on a 67-year-old man with stuporous mentality after intentional ingestion of approximately 200 ml of liquid chlorfluazuron in a suicide attempt. He was discharged after conservative treatments including gastric irrigation, charcoal, mechanical ventilation, hydration, and antibiotics for aspiration pneumonia without complications.

• Korean Journal of Poultry Science
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• v.38 no.2
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• pp.155-164
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• 2011

The use of antimicrobials will be soon removed due to an increase of occurrence of antibiotic-resistant bacteria or ionophore-resistant Eimeria species in poultry farms and consumers' preference on drug-free chicken meats or eggs. Although dietary antimicrobials contributed to the growth and health of the chickens, we do not fully understand their interrelationship among antimicrobials, gut microbiota, and host immunity in poultry. In this review, we explored the current understanding on the effects of antimicrobials on gut microbiota and immune systems of chickens. Based on the published literatures, it is clear that antibiotics and antibiotic ionophores, when used singly or in combination could influence gut microbiota. However, antimicrobial effect on gut microbiota varied depending on the samples (e.g., gut locations, digesta vs. mucosa) used and among the experiments. It was noted that the digesta vs. the mucosa is the preferred sample with the results of no change, increase, or decrease in gut microbiota community. In future, the mucosa-associated bacteria should be targeted as they are known to closely interact with the host immune system and pathogen control. Although limited, dietary antimicrobials are known to modulate humoral and cell-mediated immunities. Ironically, the evidence is increasing that dietary antimicrobials may play an important role in triggering enteric disease such as gangrenous dermatitis, a devastating disease in poultry industry. Future work should be done to unravel our understanding on the complex interaction of host-pathogen-microbiota-antimicrobials in poultry.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.17 no.3
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• pp.174-180
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• 2004

Erysipelas is a type of cellulitis in skin infection generally caused by group A ${\beta}$-hemolytic streptococci. An erysipelas skin lesion typically has a raised border that is sharply demarcated from normal skin. The underlying skin is painful, intensely red, hardened, swollen, and warm. Objectives: We reviewed three cases of erysipelas patients who hospitalized in Dongshin Univ. Suncheon Oriental medicine hospital from June 2001 to June 2002. Methods : We treated them with Galgunhaegitang(葛根解肌湯) for interior diease of Taeumin(太陰人) and also used acupuncture and cupping therapy. Results and Conclusions ; We had significant effects of Galgunhaegitang(葛根解肌湯) for three cases of erysipelas patients. So if the patient were a Taeumin(太陰人), we can consider using Galgunhaegitang(葛根解肌湯) for erysipelas. We can also use antibiotics properly in case there are high fever or open wounds.

• Animal cells and systems
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• v.6 no.4
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• pp.305-309
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• 2002

Actinorhodin antibiotics produced by Streptomyces lividans TK24 are blue pigments with a weak antibiotic activity, derived from one acetyl-CoA and 15 malonyl-CoA units via a typical ployketide pathway. In an attempt to clone polyketide biosynthetic genes of S. lividans TK24, hybridizing fragments in the genomic DNA of S. lividans TK24 were detected by use of acn and act III polyketide synthase gene probes. Since typical aromatic polyketide bio-synthetic gene clusters are roughly 22-34 Kb long, we constructed in E. coli XL-Blue MR using the Streptomyces-E. coli bifunctional shuttle cosmid vector (pojn46). Then, about 5,000 individual E. coii colonies were thor-oughly screened with acrl-ORFI and actIII probes. From these cosmid libra-ries, 12 positive clones were identified. Restriction analysis and southern hybridization showed two polyketide biosynthetic gene clusters in this organism. These cosmid clones can be transformed into Streptomyces parvulus 12434 for expression test that identify product of actinorhodin biosynthetic genes by heterologous expression. Thus, heterologous expres-sion of a derivative compound of a actinorhodin biosynthetic intermediate was obtained in pKE2430. Expression of these compounds by the trans-formants was detected by photodiode array HPLC analysis of crude extracts.

• International Journal of Oral Biology
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• v.38 no.2
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• pp.61-65
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• 2013

Erythromycin is a macrolide antibiotic and inhibits bacterial protein synthesis by stimulating the dissociation of the peptidyl-tRNA molecule from the ribosomes during elongation. The use of macrolides has increased dramatically over the last few years and has led to an increase in bacterial resistance to these antibiotics. Bacterial resistance to erythromycin is generally conferred by the ribosome methylation and/or transport (efflux) protein genes. Among the identified erythromycin-resistant genes, erm(B) (erythromycin methylation) and mef(A) (macrolide efflux) are generally detectable in erythromycin-resistant streptococcal species. The distribution of these genes in oral streptococcal isolates has been reported in studies from other countries but has not been previously examined in a Korean study. We here examined by PCR the presence of erm(B) and mef(A) in oral streptococci isolated from Korean dental plaques. Among the 57 erythromycin-resistant strains tested, 64.9% harbored erm(B) whereas 40.4% were positive for mef(A). Eleven isolates had both the erm(B) and mef(A) genes. Twenty six isolates had only erm(B) and 12 isolates had only mef(A). Eight of the 57 strains examined were negative for both genes.

• Korean Journal of Microbiology
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• v.29 no.4
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• pp.250-257
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• 1991

An obligate methanol-oxidizing bacterium, Methylobacillus sp. strain SK1, which grows only on methanol was isolated from soil. The isolate was nonmotile Gram-negtive rod. It does not have internal membrane system. The colonies were small, whitish-yellow, and smooth. The guanine plus cytosine content of the DNA was 48 mol%. Cellular fatty acids consisted predominantly of large amounts of straight-chain saturated $C_{16:0}$ acid and unsaturated $C_{16:1}$ acid. The major ubiquinone was Q-8, and Q-10 was present as minor component. The cell was obligately aerobic and exhibited catalase, but no oxidase, activity. Poly-.betha.-hydroxybutyrate, endospores, or cysts were not observed. the isolate could grow only on methanol in mineral medium. Growth factors were not required. The isolate was unable to use methane, formaldehyde, formate, methylamine, and several other organic compounds tested as a sole source of carbon and energy. Growth was optimal at 35.deg.C and pH 7.5. It could not grow at 42.deg.C. The doubling time was 1.2h at 30.deg.C when grown with 1.0%(v/v) methanol. The growth was not affected by antibiotics inhibiting cell wall synthesis and carbon monoxide but was completely suppressed by those inhibiting protein synthesis. Methanol was found to be assimilated through the ribulose monophosphate pathway. Cytochromes of b-, c-, and o- types were found. Cell-free extracts contained a phenazine methosulfate-linked methanol dehydrogenase activity, which required ammonium ions as an activator. Cells harvested after the late exponential phase seemed to contain blue protein.ein.

• Parasites, Hosts and Diseases
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• v.46 no.3
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• pp.119-125
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• 2008

Lymphatic filariasis, transmitted by mosquitoes is the commonest cause of lymphedema in endemic countries. Among 120 million infected people in 83 countries, up to 16 million have lymphedema. Microfilariae ingested by mosquitoes grow into infective larvae. These larvae entering humans after infected mosquito bites grow in the lymphatics to adult worms that cause damage to lymphatics resulting in dilatation of lymph vessels. This earliest pathology is demonstrated in adults as well as in children, by ultrasonography, lymphoscintigraphy and histopathology studies. Once established, this damage was thought to be irreversible. This lymphatic damage predisposes to bacterial infection that causes recurrent acute attacks of dermato-lymphangio-adenitis in the affected limbs. Bacteria, mainly streptococci gain entry into the lymphatics through 'entry lesions' in skin, like interdigital fungal infections, injuries, eczema or similar causes that disrupt integrity of skin. Attacks of dermato-lymphangio-adenitis aggravates lymphatic damage causing lymphedema, which gets worse with repeated acute attacks. Elephantiasis is a late manifestation of lymphatic filariasis, which apart from limbs may involve genitalia or breasts. Lymphedema management includes use of antifilarial drugs in early stages, treatment and prevention of acute attacks through 'limb-hygiene', antibiotics and antifungals where indicated, and physical measures to reduce the swelling. In selected cases surgery is helpful.

• Membrane and Water Treatment
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• v.9 no.2
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• pp.123-128
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• 2018

Common aquaculture practices include the use of certain pharmaceuticals such as antibiotics in avoiding diseases and promoting a healthier growth of the culture. The aim of this study is to monitor and assess the influence of different low oxytetracycline concentrations on the transformation of nitrogen compounds under aeration condition in a lab-scale recirculating aquaculture system (RAS). Over $1mg\;L^{-1}$ dose of oxytetracycline to aquaculture had induced ammonia($NH_4-N$), nitrate($NO_3-N$), soluble COD accumulation in RAS. In addition, nitrous oxide ($N_2O$) emission from RAS was significantly reduced during the oxytetracycline dose periods. After ceasing the dose of oxytetracycline, ammonia oxidation and nitrous oxide re-emission were observed. This observation indicated that low concentrations of oxytetracycline could affect the nitrogen species in RAS. Also, the emission mechanisms of $N_2O$ may not be only dependent on nitrification process but also dependent on denitrification process in our RAS system.

• Journal of agriculture & life science
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• v.45 no.6
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• pp.175-181
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• 2011

Effective Agrobacterium-mediated transformation of Trichoderma harzianum could be achieved using the $Al_2O_3$ particles-abraded mycelia pellets. Transformation efficiency, as percents for the number of hygromcin-resistant mycelia pellets out of total pellets tested, was about 20 in average for $Al_2O_3$ experiment. No transformed mycelium was obtained from the intact mycelia pellets. After second round of antibiotics selection, DNA integration of hygromycin resistant gene and the expression of target gene could be confirmed by PCR and RT PCR, respectively. This is the first report of Agrobacterium-mediated T. harzianum transformation.