• 한국자원식물학회지
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• 제31권4호
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• pp.342-354
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• 2018

Suaeda japonica is a halophytic plant that lives in mudflat at intertidal zone of western and southern coastal areas of Korea. The seawater-living plants showed a purple color during their whole life. In contrast, freshwater-living plants displayed a green color in leaves. When seawater-living plants were transferred to potting soil, the purple color was gradually changed to green in the leaves. The extracted purple pigment compound exhibited typical characteristics of betacyanin that were represented by water solubility, pH- and temperature-dependent color changes, sensitivity to light, UV-Vis spectra, and gel electrophoretic migration pattern. The LC-MS analysis of the extracted pigment compound showed the presence of two major protonated molecular ions ($[M+H]^+$) at m/z 651.1 and m/z 827.1. Antioxidant activity of the pigment compound was determined using stable free radical DPPH assay. It was found to have an antioxidant activity that is linearly increased in proportion to the reaction time for up to 30 min, and the activity was comparable to that of control BHA at 9.0 mg/ml. The anticancer activity against several tumor cell lines was also examined following the MTT assay. The significant growth inhibitory effect was observed on two tumor cell lines, SW-156 (human kidney carcinoma) and HEC-1B (human endometrial adenocarcinoma). Probably, the pigment compound may function as an osmolyte to uphold halotolerant physiological processes in saline environment.

• Journal of Microbiology and Biotechnology
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• 제32권11호
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• pp.1427-1434
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• 2022

Two novel, halotolerant strains of Martelella soudanensis, NC18^T and NC20, were isolated from deep subsurface sediment, deeply sequenced, and comparatively analyzed with related strains. Based on a phylogenetic analysis using 16S rRNA gene sequences, the two strains grouped with members of the genus Martelella. Here, we sequenced the complete genomes of NC18^T and NC20 to understand the mechanisms of their halotolerance. The genome sizes and G+C content of the strains were 6.1 Mb and 61.8 mol%, respectively. Moreover, NC18^T and NC20 were predicted to contain 5,849 and 5,830 genes, and 5,502 and 5,585 protein-coding genes, respectively. Both strains contain the identically predicted 6 rRNAs and 48 tRNAs. The harboring of halotolerant-associated genes revealed that strains NC18^T and NC20 might tolerate high salinity through the accumulation of potassium ions in a "salt-in" strategy induced by K⁺ uptake protein (kup) and the K⁺ transport system (trkAH and kdpFABC). These two strains also use the ectoine transport system (dctPQM), the glycine betaine transport system (proVWX), and glycine betaine uptake protein (opu) to accumulate "compatible solutes," such as ectoine and glycine betaine, to protect cells from salt stress. This study reveals the halotolerance mechanism of strains NC18^T and NC20 in high salt environments and suggests potential applications for these halotolerant and halophilic strains in environmental biotechnology.

• 미생물학회지
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• 제37권4호
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• pp.299-304
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• 2001

Teicoplanin은 Actinoplanes teichomyceticus가 생산하는 밴코마이신과 유사한 글리코펩티드계 항생제의 일종으로 메티실린 내성 황색포도상구균에 대해서도 효과가 우수한 치료제이다. 공시균주인 Actinoplanes teichomyceticus ATCC31121에 자외선을 조사하여 teicoplanin 생산성이 우수한 균주를 얻었다. 본 연구에서 우수 변이주 획득을 위한 UV 조사에 대한 균주의 치사곡선을 구하고 변이 유도 최적 조건을 확립하였다. 또한 한천 확산법을 사용하여 모균주와 변이주들의 teicoplanin 생산성 분포를 비교하였다. 변이주 가운데 가장 생산성이 높은 T1014-1를 최종적으로 획득하였으며 효소 활성도, 항생제 내성, 자가내성 및 teicoplanin 생산성을 조사하였으며 발효조에서 발효특성을 조사하였다.

• Journal of Microbiology and Biotechnology
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• 제16권4호
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• pp.605-612
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• 2006

A psychrotrophic bacterium was isolated from oil-contaminated groundwater and identified as Rhodococcus sp. YHLT-2. Growth was observed at the temperature of 4 to $30^{\circ}C$. This strain degraded various petroleum hydrocarbons such as crude oil, diesel oil, and gasoline over the whole range of temperatures tested. The Rhodococcus sp. YHLT-2 was capable of growing even at $4^{\circ}C$, exhibiting 90% of oil biodegradation after 20 days. Degradation of crude oil occurred at low temperature in nature. This strain was also able to grow at 7% NaCl, and utilized not only short chain alkenes $(C_9\;to\;C_{12})$, but also a broad range of long chain alkenes $(C_{19}\;to\;C_{32})$ present in crude oil at $4^{\circ}C$. The Rhodococcus sp. YHLT-2 is expected to be of potential use in the in situ bioremediation of hazardous hydrocarbons under low-temperature and high-salt conditions.

• Journal of Microbiology and Biotechnology
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• 제24권2호
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• pp.254-263
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• 2014

Enteromorpha polysaccharides (EP) extracted from green algae have displayed a wide variety of biological activities. However, their high molecular weight leads to a high viscosity and low solubility, and therefore, greatly restrains their application. To solve this problem, bacteria from the surface of Enteromorpha were screened, and an Alteromonas macleodii strain B7 was found to be able to decrease the molecular weight of EP in culture media. Proteins harvested from the supernatant of the A. macleodii B7 culture were subjected to native gel electrophoresis, and a band corresponding to the Enteromorpha polysaccharide lyase (EPL) was detected by activity staining. The enzyme identity was subsequently confirmed by MALDI-TOF/TOF mass spectrometry as the putative ${\alpha}$-amylase reported in A. macleodii ATCC 27126. The amylase gene (amySTU) from A. macleodii B7 was cloned into Escherichia coli, resulting in high-level expression of the recombinant enzyme with EP-degrading activity. AmySTU was found to be cold-adapted; however, its optimal enzyme activity was detected at $40^{\circ}C$. The ${\alpha}$-amylase was highly stable over a broad pH range (5.5-10) with the optimal pH at 7.5-8.0. The highest enzyme activity was detected when NaCl concentration was 2%, which dropped by 50% when the NaCl concentration was increased to 16%, showing an excellent nature of halotolerance. Furthermore, the amylase activity was not significantly affected by tested surfactants or the presence of some organic solvents. Therefore, the A. macleodii strain B7 and its ${\alpha}$-amylase can be useful in lowering EP molecular weight and in starch processing.

• Mycobiology
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• 제47권2호
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• pp.230-241
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• 2019

The Great Sebkha of Oran is a closed depression located in northwestern of Algeria. Despite the ranking of this sebkha among the wetlands of global importance by Ramsar Convention in 2002, no studies on the fungal community in this area have been carried out. In our study, samples were collected from two different regions. The first region is characterized by halophilic vegetation and cereal crops and the second by a total absence of vegetation. The isolated strains were identified morphologically then by molecular analysis. The biotechnological interest of the strains was evaluated by testing their ability to grow at different concentration of NaCl and to produce extracellular enzymes (i.e., lipase, amylase, protease, and cellulase) on solid medium. The results showed that the soil of sebkha is alkaline, with the exception of the soil of cereal crops that is neutral, and extremely saline. In this work, the species Gymnoascus halophilus, Trichoderma gamsii, the two phytopathogenic fungi, Fusarium brachygibbosum and Penicillium allii, and the teleomorphic form of P. longicatenatum observed for the first time in this species, were isolated for the first time in Algeria. The halotolerance test revealed that the majority of the isolated are halotolerant. Wallemia sp. and two strains of G. halophilus are the only obligate halophilic strains. All strains are capable to secrete at least one of the four tested enzymes. The most interesting species presenting the highest enzymatic index were Aspergillus sp. strain A4, Chaetomium sp. strain H1, P. vinaceum, G. halophilus, Wallemia sp. and Ustilago cynodontis.