• KSBB Journal
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• 제18권4호
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• pp.294-300
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• 2003

본 연구에서는 L. fermentum KLB12을 열 전처리 함으로서 제제화 과정 동안 거치게 되는 열 스트레스에 대한 내성이 증진됨을 확인하고, 최적의 열 전처리 조건을 수행하였다. 또한 열 전처리 뿐만 아니라, 저온과 열 전처리 조건에도 열 스트레스에 대한 간섭 효과를 확인하였다. 그리고 내성 증진에 신규 단백질 합성이 필요함을 확인하였으며 나아가, 2-D electrophoresis를 통하여 7개의 신규 단백질을 확인하였다. 따라서 이 균주를 제제화하기 위한 방법으로 열 전처리를 이용할 경우 생균력 유지에 큰 효과를 얻을 수 있다고 사료된다.

• ALGAE
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• 제35권1호
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• pp.91-106
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• 2020

Incorporating renewable fuel into practice, especially from algae, is a promising approach in reducing fossil fuel dependency. Algae are an exceptional feedstock since they produce abundant biomass and oils in short timeframes. Algae also produce high-valued lipid products suitable for human nutrition and supplement. Achieving goals of producing algae fuels and high-valued lipids at competitive prices involves further improvement of technology, especially better control over cultivation. Manipulating microalgae cultivation conditions to prevent contamination is essential in addition to promoting optimal growth and lipid yields. Contamination of algal cultures is a major impediment to algae cultivation that can however be mitigated by choosing extremophile microalgae. This work describes the isolation of alkali-tolerant / alkaliphilic microalgae native to South Florida with ideal characteristics for cultivation. For that purpose, water samples from Lake Okeechobee were inoculated into Zarrouk's medium (pH 9-12) and incubated for 35 days. Selection resulted in isolation of three strains that were screened for biomass and lipid accumulation. Two alkali-tolerant algae Chloroidium sp. 154-1 and Chlorella sp. 154-2 were poor lipid accumulators. One of the isolates, the diatom Fistulifera sp. 154-3, was identified as a lipid accumulating, alkaliphilic organism capable of producing 0.233 g L^-1 d^-1 dry biomass and a lipid content of 20-30% dry weight. Lipid analysis indicated the most abundant fatty acid within Fistulifera sp. was palmitoleic acid (52%), or omega-7, followed by palmitic acid (17%), and then eicosapentanoic acid (15%). 18S rRNA phylogenetic analysis formed a well-supported clade with Fistulifera species.

• 생태와환경
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• 제47권spc호
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• pp.39-47
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• 2014

바이칼호에 서식하는 2종의 스폰지 체내 및 주변 물로부터 92개의 저온성 균주를 분리하고 각 균주들의 기질 분해능을 조사하였다. 그 결과 섬유소와 지방에 대한 분해 활성도를 갖는 균주는 38.0, 34.8%로 비교적 적었으나 전분과 단백질 분해 활성도를 갖는 균주는 78.3, 57.6%로 높은 비율로 나타났다. 분리한 세균을 염기서열의 유사도에 따라 분류하기 위하여 Genomic Fingerprinting을 실시한 후 31개 균주를 선별하여 동정한 결과, Baikalospongia sp.에서 분리한 13균주는 모두 Pseudomonas속으로 확인된 반면, Lubomirskia sp.에서 분리한 14균주는 Pseudomonas ssp., Buttiauxella agrestis, Pseudomonas fluorescens, Yersinia ruckeri, Bacillus ssp., Paenibacillus ssp., Bacillus thuringiensis, Bacillus simplex, Brevibacterium ssp., Acinetobacter lwoffii로 다양하게 동정되었다. 그러나 총 31개 균주 중 18개가 Pseudomonas속으로 동정된 것은 타감작용에 의한 다른 세균 성장의 방해 때문으로 평가되며, 이러한 일반적인 배양 방법의 한계점을 극복하기 위해서는 스폰지의 서식처와 세균의 검출 방법에 대하여 보다 다양한 심층적인 연구가 이루어져야 할 것으로 생각된다.

• 한국축산식품학회지
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• 제41권6호
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• pp.967-982
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• 2021

Probiotics are living microorganisms that, when administered in adequate amounts, provide a health benefit to the host and are considered safe. Most probiotic strains that are beneficial to human health are included in the "Lactic acid bacteria" (LAB) group. The positive effects of probiotic bacteria on the host's health are species-specific and even strain-specific. Therefore, evaluating the probiotic potential of both wild and novel strains is essential. In this study, the probiotic characteristics of Lactobacillus brevis KT38-3 were determined. The strain identification was achieved by 16S rRNA sequencing. API-ZYM test kits were used to determine the enzymatic capacity of the strain. L. brevis KT38-3 was able to survive in conditions with a broad pH range (pH 2-7), range of bile salts (0.3%-1%) and conditions that simulated gastric juice and intestinal juice. The percentage of autoaggregation (59.4%), coaggregation with E. coli O157:H7 (37.4%) and hydrophobicity were determined to be 51.1%, 47.4%, and 52.7%, respectively. L. brevis KT38-3 produced β-galactosidase enzymes and was able ferment lactose. In addition, this strain was capable of producing antimicrobial peptides against the bacteria tested, including methicillin and/or vancomycin-resistant bacteria. The cell-free supernatants of the strain had high antioxidant activities (DPPH: 54.9% and ABTS: 48.7%). Therefore, considering these many essential in vitro probiotic properties, L. brevis KT38-3 has the potential to be used as a probiotic supplement. Supporting these findings with in vivo experiments to evaluate the potential health benefits will be the subject of our future work.

• 한국버섯학회지
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• 제17권1호
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• pp.19-23
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• 2019

Pseudomonas agarici에 의해 발생하는 세균성회색무늬병은 양송이버섯 재배에서 문제가 되는 대표적인 병해이다. 본 연구에서는 세균성회색무늬병의 생물학적 방제법에 이용할 수 있는 길항미생물의 항균활성과 선발된 길항미생물에 대해 폿트 수준의 생물검정 실험을 실시하였다. 재배중인 양송이버섯 배지에서 세균성회색무늬병 병원균을 강하게 억제하는 길항세균 HC42를 선발하였으며, 생리 생화학적 실험과 유전적 실험결과 HC42균주는 B. safensis로 동정되었다. B. safensis HC42를 양송이에 처리한 결과 66%의 방제효과를 보였다. 따라서 B. safensis HC42가 양송이버섯 세균성회색무늬병 방제를 위해 합성농약을 대체할 수 있는 친환경 방제제가 될 수 있을 것으로 생각된다.

• The Plant Pathology Journal
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• 제37권6호
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• pp.662-672
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• 2021

Plant growth-promoting bacteria improve plant growth under abiotic stress conditions. However, their effects on microbial succession in the rhizosphere are poorly understood. In this study, the inoculants of Bacillus mesonae strain H20-5 were administered to tomato plants grown in soils with different salinity levels (EC of 2, 4, and 6 dS/m). The bacterial communities in the bulk and rhizosphere soils were examined 14 days after H20-5 treatment using Illumina MiSeq sequencing of the bacterial 16S rRNA gene. Although the abundance of H20-5 rapidly decreased in the bulk and rhizosphere soils, a shift in the bacterial community was observed following H20-5 treatment. The variation in bacterial communities due to H20-5 treatment was higher in the rhizosphere than in the bulk soils. Additionally, the bacterial species richness and diversity were greater in the H20-5 treated rhizosphere than in the control. The composition and structure of the bacterial communities varied with soil salinity levels, and those in the H20-5 treated rhizosphere soil were clustered. The members of Actinobacteria genera, including Kineosporia, Virgisporangium, Actinoplanes, Gaiella, Blastococcus, and Solirubrobacter, were enriched in the H20-5 treated rhizosphere soils. The microbial co-occurrence network of the bacterial community in the H20-5 treated rhizosphere soils had more modules and keystone taxa compared to the control. These findings revealed that the strain H20-5 induced systemic tolerance in tomato plants and influenced the diversity, composition, structure, and network of bacterial communities. The bacterial community in the H20-5 treated rhizosphere soils also appeared to be relatively stable to soil salinity changes.

• 식물병연구
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• 제28권3호
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• pp.172-178
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• 2022

The graft cactus (Gymnocalycium mihanovichii) continues to be exported to more than 20 countries worldwide. In April 2021, typical bacterial symptoms of soft rot were observed in the graft cactus (cv. Yeonbit) in Goyang, Gyeonggi-do, Korea, resulting in economic losses in cactus production. The stems turned dark brown and the flowers were covered with black rot. The bacterial strain designated as KNUB-01-21 was isolated from infected stems and flowers. The results of the morphological and biochemical tests of the isolate were similar to those of Pectobacterium brasiliense. For molecular analysis, the 16S rRNA region and three housekeeping genes (dnaX, leuS, and recA) of the strain KNUB-01-21 were amplified. Based on the results of the molecular analysis and morphological and biochemical tests, KNUB-01-21 was identified as P. brasiliense. The pathogenicity of KNUB-01-21 on graft cactus was confirmed by an inoculation test. Artificial inoculation using P. brasiliense KNUB-01-21 produced soft rot symptoms on the grafted cactus, and the same bacterium was re-isolated and re-identified. This is the first report of P. brasiliense causing soft rot in graft cactus in Korea.

• International Journal of Industrial Entomology and Biomaterials
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• 제47권1호
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• pp.1-11
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• 2023

The Indian golden muga silkworm, Antheraea assamensis Helfer is an economically important wild silkworm endemic to Northeastern part of India. In recent years, climate change has posed a threat to muga silk production due to the requirement that larvae be reared outdoors. Since the muga silkworm larvae are exposed to the vagaries of nature, the changing climate has increased the incidence of microbial diseases in the rearing fields. Accurate diagnosis of the disease causing pathogens and its associated epidemiology are prerequisites to manage the diseases in the rearing field. Although conventional microbial culturing methods are widely used to identify pathogenic bacteria, they would not provide meaningful information on a wide variety of silkworm pathogens. The information on use of molecular diagnostic tools in detection of microbial pathogens of wild silk moths is very limited. A wide range of molecular and immunodiagnostic techniques including denaturing gradient gel electrophoresis (DGGE), random amplified polymorphism (RAPD), 16S rRNA/ITSA gene sequencing, multiplex polymerase chain reaction (M-PCR), fluorescence in situ hybridization (FISH), immunofluorescence, and repetitive-element PCR (Rep-PCR), have been used for detecting and characterizing the pathogens of insects with economic significance. Nevertheless, the application of these molecular tools for detecting and typing entomopathogens in surveillance studies of muga silkworm rearing is very limited. Here, we discuss the possible application of these molecular techniques, their advantages and major limitations. These methods show promise in better management of diseases in muga ecosystem.

• Journal of Veterinary Science
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• 제24권3호
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• pp.38.1-38.12
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• 2023

Background: Poor disease management and irregular vector control could predispose sheltered animals to disease such as feline Bartonella infection, a vector-borne zoonotic disease primarily caused by Bartonella henselae. Objectives: This study investigated the status of Bartonella infection in cats from eight (n = 8) shelters by molecular and serological approaches, profiling the CD4:CD8 ratio and the risk factors associated with Bartonella infection in shelter cats. Methods: Bartonella deoxyribonucleic acid (DNA) was detected through polymerase chain reaction (PCR) targeting 16S-23S rRNA internal transcribed spacer gene, followed by DNA sequencing. Bartonella IgM and IgG antibody titre, CD4 and CD8 profiles were detected using indirect immunofluorescence assay and flow cytometric analysis, respectively. Results: B. henselae was detected through PCR and sequencing in 1.0% (1/101) oral swab and 2.0% (1/50) cat fleas, while another 3/50 cat fleas carried B. clarridgeiae. Only 18/101 cats were seronegative against B. henselae, whereas 30.7% (31/101) cats were positive for both IgM and IgG, 8% (18/101) cats had IgM, and 33.7% (34/101) cats had IgG antibody only. None of the eight shelters sampled had Bartonella antibody-free cats. Although abnormal CD4:CD8 ratio was observed in 48/83 seropositive cats, flea infestation was the only significant risk factor observed in this study. Conclusions: The present study provides the first comparison on the Bartonella spp. antigen, antibody status and CD4:CD8 ratio among shelter cats. The high B. henselae seropositivity among shelter cats presumably due to significant flea infestation triggers an alarm of whether the infection could go undetectable and its potential transmission to humans.

• 한국환경농학회지
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• 제41권4호
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• pp.344-354
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• 2022

BACKGROUND: Although antibiotics have contributed to treatment of bacterial infection, the antibiotic abuse can lead to antibiotic resistant bacteria. Impact of human activities on distribution of antibiotic resistance has been intensively issued and occurrence of antibiotic resistant bacteria in contaminated environments would not be a surprise. Nonetheless, anthropogenic contamination with the dissemination of antibiotic resistance along uncontaminated environments has been less considered. The aim of this study is to investigate antibiotic resistant bacteria across Ulleungdo, known as antibiotic resistance free and anthropogenic pollution free environment in Rep. of Korea. METHODS AND RESULTS: Antibiotic resistant bacteria in coastal seawater of Ulleungdo were investigated in July 2021. Antibiotic susceptibility test using the disk diffusion method was applied with six drugs according to the Clinical and Laboratory Standards Institute (CLSI) guideline. Total 43 bacterial isolates were tested and 20 isolates among of them showed multidrug resistance. Particularly, the number and ratio of resistant bacteria were relatively high in a densely populated area of Ulleungdo. The bacterial communities were investigated using 16S rRNA gene metabarcoding approach in the coastal seawater and soils of Ulleungdo. In the bacterial communities, Firmicutes were selectively distributed only in seawater, suggesting the possibility of anthropogenic contamination in coastal seawater of Ulleungdo. CONCLUSION(S): We found antibiotic resistant bacteria in a populated area of Ulleungdo. The occurrence of antibiotic resistant bacteria in Ulleungdo seems to result from the recent anthropogenic impact. Consistent monitoring of antibiotic resistant bacteria in the uncontaminated environment needs to considered for future risk assessment of antibiotics.