• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.5
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• pp.712-720
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• 2022

In this study, we evaluated the production and photoreactivity of CDOM of two polar phytoplanktons - Phaeocystis antarctica and Phaeocystis pouchetii, in order to find out UV effects on phytoplanktons. In visible region, CDOM in media of both phytoplanktons under UV-R decreased during 48hrs incubation period. However, in UV region CDOM decreased 30 % in the media of P. antarctica, but increased 10% in media of P. pouchetii, compared to CDOM concentrations of control after 48 hr incubation. This result indicates that biota in polar environment would not well protected from UV-R harmful effect when P. antarctica is dominant because of loss of CDOM, but when P. pouchetii is dominant species, production of UV absorbing organic matter could play more efficiently for UV screening for marine biota. Also we confirmed that FDOM of humic substance (C-peak) produced by these phtoplanktons under UV-R stress were well matched with fluorescence characteristics of the UV-protecting compound, MAAs. This finding shows that Phaeocystis pouchetti with low photoreactivity would contribute to DOM pool of polar marine environment under stratification by global warming.

• Journal of Photoscience
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• v.9 no.2
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• pp.466-469
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• 2002

An experiment has been conducted to measure the impact of UV radiation sensitivity on dermatophytes (Microsporum boullardii) by different UV radiation exposure time interval (1 min, 2 min 5 min, 10 min and 20 min) in degradation of keratin (Feather) in growth promoting substances of protein, cysteine, cystine and methionine from 7 to 28 days of incubation period. Mutant strain caused maximum weight loss with 1 minutes of UV radiation exposure at 21 day and mutant strain became immune in sensitivity at 14 days for decomposition of feathers. Maximum protein caused at 21st days with 20 minutes U.V radiation exposure and immune sensitivity had deducted with other UV radiation exposure time. On 28 days, mutant strains became immune with all exposure times, Whereas maximum methionine caused at 21st days with 20 minutes UV radiation exposure. Maximum cysteine caused at $14^{th}$ day with 5 minutes UV radiation exposure and mutant strain showed immune response at all time periods. Cystine production was also followed by cysteine at 21 day and also showed complete immune response with 1 and 2 minutes UV radiation exposure at7 and 14 days. Thus mutant strain of Microspornm boullardii can be used as a biotechnological tool for production of growth promoting substances.

• Asian-Australasian Journal of Animal Sciences
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• v.1 no.2
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• pp.99-106
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• 1988

A high performance liquid chromatographic procedure is described for the direct determination of the picomole amount of palmitoyl-Coenzyme A and stearoyl-Coenzyme A, using a stainless steel column packed with C-18 derivatized porous silica ($5{\mu}m$), an isocratic elution with a mixture of 33 mM $KH_2PO_4$/acetonitrile as a mobile phase and a UV detector. The long-chain acyl-Coenzyme A esters were determined in incubated microsomal fractions of a bovine liver to demonstrate the utility of this method for monitoring acyl-CoA synthesis in biological samples. The reaction rate of palmitate was higher than that of stearate. After a 60 minute incubation period, the generated amount of palmitoyl-Coenzyme A and stearoyl-Coenzyme A were approximately 70 and 20 n mol/mg micresomal protein, respectively. The advantage of this method are in that no decomposition of the CoA esters is involved, while the constituent molecular species is detected.

• Journal of Korean Society on Water Environment
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• v.26 no.6
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• pp.976-985
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• 2010

In this study, characteristics of dissolved organic matter (DOM) from Lake Paldang and seven other DOM sources (lake plankton, plants, soil, composite, treated sewage) were studied using XAD resin fractionation and 28-day microbial incubation experiment. Distribution patterns of DOM-fractions, which include hydrophilic acids (HiA), hydrophilic bases (HiB), hydrophilic neutrals (HiN), hydrophobic acids (HoA), hydrophobic neutrals (HoN) and the extent of DOM biodegradation (i.e., biodegradability) were different depending on the origins of the DOM samples. The DOM distribution pattern and the biodegradability were found to be effective for distinguishing the different DOM sources. The biodegradability (%) had negative correlations with the content (%) of hydrophobic fractions (Ho) and specific UV absorbance of DOM, which indicate that the Ho fractions contain more aromatic carbon structures and relatively stable during biodegradation, irrespective of the sources. To gain additional insight into the microbial transformation of the DOM, we also investigated the changes in the fraction's distribution for plankton, leaf litter and composite samples after the incubation. The results showed that biodegradation of hydrophilic fraction (Hi) causes an increase in the proportion of Ho (HoA, HoN), while biodegradation of HoA increases the HoN production.

• KSBB Journal
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• v.9 no.5
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• pp.469-474
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• 1994

The purpose of the work was to evaluate the feasibility of a biological treatment process for the phenoxy alkanoic herbicide 2,4-D(2,4-dichlorophenoxyacetic acid) as a commercial pesticide. The phenoxy herbicide was 2,4-D amine salts which contained 40%(vol/vol) 2,4-D and 60%(vol/vol) solvent. A microbial consortium has been derived by enrichment with 2,4-D. The consortium utilized 2,4-D as the sole source of carbon and energy. Optimal pH on the 2,4-D degradation was 7.0 in this experiment. As concentrations of 2,4-D were increased, the degradation by microbial consontium became inhibited. The amendment with yeast extract and ascorbic acid accelerated the degradation of 2,4-D. High performance liquid chromatography methodology was used to measure 2,4-D and it also resolved 2,4-DCP(2,4-dichlorophenol), the corresponding phenol as intermediate. Gas chromatography-mass spectrometry was used for preliminary identification of the intermediate 2,4-DCP. UV scans of spent cultures showed that the maximum absorption of 2,4-D at the wavelength of 283 nm was decreased toward the end of incubation, but the consortium displayed no detectable spectral changes or peak shifts in the UV absorbance.

• Microbiology and Biotechnology Letters
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• v.35 no.3
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• pp.196-202
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• 2007

Mutations in the cystathionine ${\beta}$-synthase (CBS) gene cause homocystinuria, the most frequent inherited disorder in sulfur metabolism. CBS is the unique enzyme using both heme and pyridoxal 5-phosphate (PLP) for activity. Among the reported 140 mutations, one of the most common disease-causing alterations in human CBS is G307S mutation. To investigate the pathogenic mechanism of G307S by spectroscopic methods, we engineered the full length and the truncated G247S mutation of yeast CBS that is corresponding mutation to human G307S. Yeast CBS does not contain heme and thus gives a merit to study the spectroscopic properties. The UV-visible spectra of the purified full length and the truncated G247S yeast CBSs showed the total absence of PLP in the protein. The absence of PLP in G247S mutation was also confirmed by the PLP-cyanide adduct formation experiment, which was conducted by the incubation of the purified enzyme with KCN. The adducts were detected using a circular dichroism (CD) and a spectrofluorimeter. Radio isotope activity assay of full length and truncated G247S proteins also gave no activity. Our yeast G247S mutation data suggested that G307S might make the distortion of the active site so that cofactor PLP and substrate can not fit inside the active site. Our yeast CBS study addressed the reason why the G307S mutation in human CBS makes the enzyme inactive that consequently leads to severe clinical phenotype.