• Parasites, Hosts and Diseases
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• 제57권4호
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• pp.341-357
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• 2019

Acanthamoeba, one of free-living amoebae (FLA), remains a high risk of direct contact with this protozoan parasite which is ubiquitous in nature and man-made environment. This pathogenic FLA can cause sight-threatening amoebic keratitis (AK) and fatal granulomatous amoebic encephalitis (GAE) though these cases may not commonly be reported in our clinical settings. Acanthamoeba has been detected from different environmental sources namely; soil, water, hotspring, swimming pool, air-conditioner, or contact lens storage cases. The identification of Acanthamoeba is based on morphological appearance and molecular techniques using PCR and DNA sequencing for clinico-epidemiological purposes. Recent treatments have long been ineffective against Acanthamoeba cyst, novel anti-Acanthamoeba agents have therefore been extensively investigated. There are efforts to utilize synthetic chemicals, lead compounds from medicinal plant extracts, and animal products to combat Acanthamoeba infection. Applied nanotechnology, an advanced technology, has shown to enhance the anti-Acanthamoeba activity in the encapsulated nanoparticles leading to new therapeutic options. This review attempts to provide an overview of the available data and studies on the occurrence of pathogenic Acanthamoeba among the Association of Southeast Asian Nations (ASEAN) members with the aim of identifying some potential contributing factors such as distribution, demographic profile of the patients, possible source of the parasite, mode of transmission and treatment. Further, this review attempts to provide future direction for prevention and control of the Acanthamoeba infection.

• 한국미생물·생명공학회지
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• 제24권4호
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• pp.500-506
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• 1996

Bacillus subtilis SH-1 screened from coastal sea water of South Korea was used to produce bacteriolytic enzyme. The production of bacteriolytic enzyme by immobilized cells was investigated. The optimum conditions for the continuous production of the bacteriolytic enzyme using immobilized cells were 2.4 mm diameter of 0.3% alginate beads, 20 ml/h of substrate feeding rate and 20 l/min of aeration rate. A productivity of 76.5 to 88.0 units/ml could be obtained for 25 days by continuous column reactor under the optimum conditions.

• 한국미생물생명공학회:학술대회논문집
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• 한국미생물생명공학회 1986년도 추계학술대회
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• pp.522.2-522
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• 1986

In order to optimally induce sporulation and toxin formation in Bacillus thuringiensis, exhaustion of specific nutrients as well as resuspension experiments were tried. Sporulation and toxin formation was most abunduntly occurred when the growth was limited by carbon source. It was also occurred in a resuspension medium containing only distilled water. Various environmental and physiological factors affecting the efficiencies of spore and toxin formation were examined in chemically defined media. As a result of these studies, a batch fermentation resulted in higher spore and toxin yield than ever reported

• 한국미생물·생명공학회지
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• 제22권6호
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• pp.643-645
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• 1994

Chitin and chitosan has been almost neglected until 1960s, although they are the second largest biomass on earth. Their major use were as a natural flocculant for waste-water treatment, and partially used in the areas of food, feed industry, cosmetics and medicine. Possible sources of chitin among biomass were tested, and antibacterial activity and viscosity-concentration relation- ship of diluted acidic solution were examined.

• Journal of Microbiology
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• 제45권2호
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• pp.87-97
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• 2007

Medium-chain-length polyhydroxyalkanoates (MCL-PHAs), which have constituents with a typical chain length of $C_{6}-C_{14}$, are polyesters that are synthesized and accumulated in a wide variety of Gram-negative bacteria, mainly pseudomonads. These biopolyesters are promising materials for various applications because they have useful mechanical properties and are biodegradable and biocompatible. The versatile metabolic capacity of some Pseudomonas spp. enables them to synthesize MCL-PHAs that contain various functional substituents; these MCL-PHAs are of great interest because these functional groups can improve the physical properties of the polymers, allowing the creation of tailor-made products. Moreover, some functional substituents can be modified by chemical reactions to obtain more useful groups that can extend the potential applications of MCL-PHAs as environmentally friendly polymers and functional biomaterials for use in biomedical fields. Although MCL-PHAs are water-insoluble, hydrophobic polymers, they can be degraded by microorganisms that produce extracellular MCL-PHA depolymerase. MCL-PHA-degraders are relatively uncommon in natural environments and, to date, only a limited number of MCL-PHA depolymerases have been investigated at the molecular level. All known MCL-PHA depolymerases share a highly significant similarity in amino acid sequences, as well as several enzymatic characteristics. This paper reviews recent advances in our knowledge of MCL-PHAs, with particular emphasis on the findings by our research group.

• 동의생리병리학회지
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• 제22권2호
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• pp.438-445
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• 2008

Dodam formula (Dodam) has been used for neurodegenerative disease in Oriental medicine. Dodam is capable of protecting diverse kinds of cells from damage caused by a variety of toxic stimuli. In the present study, we investigated the underlying protective mechanism of Dodam on rotenone-induced cytotoxicity in rat neuroblastoma Neuro-2A cells. Treatment with Neuro-2A cells with rotenone caused the loss of cell viability, and condensation and fragmentation of nuclei, which was associated with the elevation of ROS level, and lipid peroxidation, the increase in Bax/Bcl-2 ratio. Rotenone induced mitochondrial dysfunction characterized by mitochondrial membrane potential loss and cytochrome-c release. These phenotypes induced by rotenone were reversed by pretreatment with Dodam. Our results suggested that major features of rotenone-induced neurotoxicity are partially mediated by mitochondrial dysfunction and oxidative stress, and that Dodam markedly protects Neuro-2A cells from oxidative injury. These data indicated that Dodam might provide a useful therapeutic strategy in treatment of the neurodegenerative diseases caused by oxidative injuries.

• Journal of Microbiology and Biotechnology
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• 제31권4호
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• pp.520-528
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• 2021

Plesiomonas shigelloides, a member of the family Vibrionaceae, is a gram-negative, rod-shaped, facultative anaerobic bacterium with flagella. P. shigelloides has been isolated from such sources as freshwater, surface water, and many wild and domestic animals. P. shigelloides contains 102 O-antigens and 51 H-antigens. The diversity of O-antigen gene clusters is relatively poorly understood. In addition to O1 and O17 reported by other laboratories, and the 12 O serogroups (O2, O10, O12, O23, O25, O26, O32, O33, O34, O66, O75, and O76) reported previously by us, in the present study, nine new P. shigelloides serogroups (O8, O17, O18, O37, O38, O39, O44, O45, and O61) were sequenced and annotated. The genes for the O-antigens of these nine groups are clustered together in the chromosome between rep and aqpZ. Only O38 possesses the wzm and wzt genes for the synthesis and translocation of O-antigens via the ATP-binding cassette (ABC) transporter pathway; the other eight use the Wzx/Wzy pathway. Phylogenetic analysis using wzx and wzy showed that both genes are diversified. Among the nine new P. shigelloides serogroups, eight use wzx/wzy genes as targets. In addition, we developed an O-antigen-specific PCR assay to detect these nine distinct serogroups with no cross reactions among them.

• Journal of Microbiology and Biotechnology
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• 제21권2호
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• pp.115-123
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• 2011

To investigate the effects of pipe materials on biofilm accumulation and water quality, an annular reactor with the sample coupons of four pipe materials (steel, copper, stainless steel, and polyvinyl chloride) was operated under hydraulic conditions similar to a real plumbing system for 15 months. The bacterial concentrations were substantially increased in the steel and copper reactors with progression of corrosion, whereas those in stainless steel (STS) and polyvinyl chloride (PVC) reactors were affected mainly by water temperature. The heterotrophic plate count (HPC) of biofilms was about 100 times higher on steel pipe than other pipes throughout the experiment, with the STS pipe showing the lowest bacterial number at the end of the operation. Analysis of the 16S rDNA sequences of 176 cultivated isolates revealed that 66.5% was Proteobacteria and the others included unclassified bacteria, Actinobacteria, and Bacilli. Regardless of the pipe materials, Sphingomonas was the predominant species in all biofilms. PCR-DGGE analysis showed that steel pipe exhibited the highest bacterial diversity among the metallic pipes, and the DGGE profile of biofilm on PVC showed three additional bands not detected from the profiles of the metallic materials. Environmental scanning electron microscopy showed that corrosion level and biofilm accumulation were the least in the STS coupon. These results suggest that the STS pipe is the best material for plumbing systems in terms of the microbiological aspects of water quality.

• 한국버섯학회지
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• 제3권4호
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• pp.140-144
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• 2005

여름철 팽이버섯 병재배시 톱밥배지에서 발생하는 균사생장 억제증상의 원인을 구명하고 그 경감대책을 확립하기 위하여 톱밥배지 배합시 물온도를 $24^{\circ}C$(상온수)와 $6^{\circ}C$(저온수)로 하고, 배지제조후 살균전 경과시간을 0, 3, 6, 9시간으로 달리하여 팽이버섯의 재배시험을 수행하였다. 배지제조 후 살균전 시간이 경과함에 따라 배지온도가 상승하고, pH는 6.5에서 5.2~5.6으로 낮아지는 경향이었다. 이때 톱밥배지 내에서 세균밀도가 증가하였으며, 물온도 $24^{\circ}C$에서는 $6^{\circ}C$보다 6시간 이후의 세균밀도가 1.9~4.1배 높았다. 톱밥배지에서 분리한 세균과 대치배양시 팽이버섯균의 생장이 억제되었다. 또한 배지제조후 살균전 시간이 경과함에 따라 배지내의 전질소 함량이 감소하였으며 유리당의 함량도 종류에 따라서 증가 또는 감소하였다. 배지배합시 $24^{\circ}C$물 처리구는 $6^{\circ}C$물 처리구에 비하여 팽이버섯 병재배사에서 균배양기간 및 버섯발생기간이 각각 1~2일 지연되는 경향이었으며, 자실체 수량도 저온수 처리구에서 안정적이었다. 그리고 9시간 경과한 배지에서는 균사생장이 정지되었다. 배지제조후 경과시간에 따라 팽이버섯 발생기간은 1~3일이 지연이 되었으며, 자실체 수량은 6시간이 경과된 배지에서 7~12% 감소하는 경향이었다. 본 시험은 여름철 고온기의 팽이버섯 재배시 배지제조에 $6^{\circ}C$이하의 저온수를 사용하여 배지내 미생물 증식을 억제시키고, 입병작업을 마치는 즉시 고압살균 함으로써 배지의 성분을 안정화시켜 버섯의 안정생산에 기여할 것으로 기대된다.

• Journal of Microbiology
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• 제35권4호
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• pp.284-289
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• 1997

A Gram (-), rod-shaped bacterium $2.3{\sim}2.8{\times}0.45{\mu}m$ in size which exhibited growth-inhibiting effects against a cyanobacterium (Anabaena cylindrica) was isolated from Daechung Dam Reservoir. This isolate was identified as Moraxella sp. and designated Moracella sp. CK-1. Hollow zones formed around bacterial colonies on the cyanobacterial lawn. In a mixed-culture of A. cylindrica and the isolate, each microorganism grew inverse-proportionally, and the cyanobacterial vegetative cells completely disappeared within 24 hours. On treatment with Moraxella sp. CK-1, cell walls of A. cylindrica disappeared, but sheathes remained in a more electron dense form. The unit membrane such as thylakoidal membrane was stable to bacterial lysing activity. This bacterium showed a broad action spectrum against cyanobacteria. The growth-inhibiting activity of Moracella sp. CK-1 against A. cylindrica is believed to be performed through the excretion of active substances.