• Food Science of Animal Resources
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• v.44 no.4
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• pp.779-789
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• 2024

The effects of irradiation on meat constituents including water, proteins, and lipids are multifaceted. Irradiation leads to the decomposition of water molecules, resulting in the formation of free radicals that can have both positive and negative effects on meat quality and storage. Although irradiation reduces the number of microorganisms and extends the shelf life of meat by damaging microbial DNA and cell membranes, it can also accelerate the oxidation of lipids and proteins, particularly sulfur-containing amino acids and unsaturated fatty acids. With regard to proteins, irradiation affects both myofibrillar and sarcoplasmic proteins. Myofibrillar proteins, such as actin and myosin, can undergo depolymerization and fragmentation, thereby altering protein solubility and structure. Sarcoplasmic proteins, including myoglobin, undergo structural changes that can alter meat color. Collagen, which is crucial for meat toughness, can undergo an increase in solubility owing to irradiation-induced degradation. The lipid content and composition are also influenced by irradiation, with unsaturated fatty acids being particularly vulnerable to oxidation. This process can lead to changes in the lipid quality and the production of off-odors. However, the effects of irradiation on lipid oxidation may vary depending on factors such as irradiation dose and packaging method. In summary, while irradiation can have beneficial effects, such as microbial reduction and shelf-life extension, it can also lead to changes in meat properties that need to be carefully managed to maintain quality and consumer acceptability.

• KSBB Journal
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• v.24 no.3
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• pp.217-226
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• 2009

p53 undergoes various post-translational modifications, including phosphorylation, ubiquitination, sumoylation, acetylation, methylation, and poly(ADP-ribosyl)ation. Modification of p53 widely affects to various functions of p53. Acetylation and phosphorylation of p53 have been studied for regulating its transcriptional activity which is observed in various stress condition. Otherwise, ubiquitination of p53 by Mdm2 has been well-studied as a canonical ubiquitin-mediated proteasomal degradation pathway. Moreover several investigators have recently reported that ubiquitination of p53 modulates not only its proteasome-dependent degradation by poly-ubiquitination but also its localization and transcriptional activity by mono-ubiquitination which usually does not serve the proteasome dependent degradation. Here we review recent studies on the cellular functions of p53 regulated by post-translational modifications, particularly focusing on mechanisms of ubiquitination.

• Microbiology and Biotechnology Letters
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• v.31 no.4
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• pp.408-412
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• 2003

The purpose of this study was to evaluate the Influence of oil concentration and inoculum size on petroleum biodegradation in soil by Nocardia sp. H17-1, isolated from oil-contaminated soil. To investigate the effect of initial oil concentration on total petroleum hydrocarbon (TPH) degradation, the soil was artificially contaminated with 10, 50 or 100 g of Arabian light oil per kg of soil, respectively. After 50 days, Nocardia sp. H17-1 degraded 78,94 and 53% of the each initial TPH concentration, respectively. Also, it produced 1.35, 4.21, and 5.91 mmol of $CO_2$ per g of soil, respectively. The degradation rate constant (k) of TPH was decreased in proportion to the initial oil concentrations while $CO_2$ production was increased with the concentration. The growth of Nocardia sp. H17-1 was remarkably inhibited when it was inoculated into soil containing 100 g of oil per kg of soil. To evaluate the effect of the inoculum size, the soil was artificially contaminated with 50 g of Arabian light oil per kg of soil, and inoculated with $3${\times}$10^{6}$ , $5${\times}$10^{7}$ , $2${\times}$10^{8}$ cells per g of soil, respectively. After 50 days, the degradation of TPH was remained with similar in all treatment but degradation rate constant (k) and evolved $CO_2$ was increased with increasing the inoculum size.

• Journal of Animal Science and Technology
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• v.48 no.5
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• pp.699-708
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• 2006

Ground rice, barley and corn were fed separately to the ruminally cannulated Hanwoo (Korean native cattle) for comparing their in situ and in vitro degradabilities, microbial growth, pH and gas production. It has been found that nearly all the dry matter (DM) and organic matter (OM) in barley and rice disappeared during 24 hr suspension in the rumen, but those in corn were only reduced by around 67%. Water soluble DM and OM fractions(‘a’), ranked from highest to lowest was corn, then rice and finally barley, but the order was reversed for content ‘b’, degradable fraction during time ‘t’. Judging by the degradation parameter of ‘b’ fraction, degradation rates per hour of DM and OM for barley were 38.3% and 37.2% respectively, significantly higher than those for rice (7.7% and 5.6%) and corn (4.1% and 1.3%). In general, results obtained from in vitro degradability of DM and OM were lower than those from in situ trials, but the ranking order of degradability was in agreement between both trials. In particular, ground rice has relatively lower in vitro microbial growth than corn or barley, but exhibited higher gas production. In addition, in vitro microbial growth of ground rice increased with up to 12 hr of incubation period, thereafter experienced a decrease with extended incubation time. pH of in vitro solution of rice decreased following 9 hr of incubation but gas production increased rapidly during the same period. From the results of DM and OM degradabilities and pH changes of in vitro solution with incubation time, it is concluded that rice represents a good source of energy for stability of rumen fermentation.

• 보존과학연구
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• s.35
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• pp.111-119
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• 2014

Microorganisms were isolated from Dongchundang(wooden cultural heritage) with PDA medium culture. Nineteen species shows the cellulolytic activity. Methylobacterium sp. was the most active in cellulose degradation. The growth curve and pH were measured during incubation of the microorganism for 72 hours. The pH was increased with the increasing of microbial growth. The degree of cellulose degradation was determined with the amount of reducing sugar by use of dinitrosalicylic acid (DNS) method. The amount of reducing sugar was decreased after 45 hours. As a results, It should suggested that wood component were deteriorated by Methylobacterium sp..

• Korean Journal of Microbiology
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• v.28 no.1
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• pp.71-75
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• 1990

The isolates biodigrading crude oil were examined to characterize thier properties. Isolates which were identified as Acinetobacter lwoffii G1, Klebsiella pneumoniae L25, Pseudomonas maltophilia N246, Xanthomonas campestris M12, and Xanthomonas sp. M28. The optimum concentration of crude oil was 0.15% for the bacterial growth. X. campestris M12, Xanthomonas sp. M28, and K. penumoniae L25 showed the maximal growth at the concentration of 3.5% sodium chloride, indicating that they were derived from sea water. Among the isolates, X. campestris M12, Xanthomonas sp. M28 specially utilized hexadecane and octane, and P. maltophilia N246 utilized octane with optimum concentration of 0.2-0.3% as sole carbon source. The utilization of components of saturate fraction by K. pneumoniae L25 was examined by gas-liquid chromatography. The short-chain saturates are used before the long chain ones although they almost disappear within 8 days of incubation at $30^{\circ}C$.

• Journal of Biosystems Engineering
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• v.43 no.2
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• pp.110-118
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• 2018

Purpose: In this study, the potential for biogas production, degradation rates, and lag-phase of diauxic growth of carbohydrate-based material, which is one of the proximate compositions, were investigated. Methods: This study was conducted using starch as a carbohydrate-based material. In experimental condition 1, the biogas potential of carbohydrate-based material was measured. In experimental condition 2, the effect of feed to microorganism ratio (F/M ratio) on lag-phase of diauxic growth from carbohydrate-based material was tested. Biochemical methane potential tests were performed at five different feed to microorganism ratios (0.2, 0.4, 0.6, 0.8, and 1.0) under mesophilic conditions. The biogas production patterns, lag-phase, total volatile fatty acids to total alkalinity ratio (TVFA/TA ratio), and time required for 90 percent biogas production were used to evaluate biogas production based on the biochemical methane potential tests. Results: In experimental condition 1, unlike previous studies, biogas was produced in the TVFA/TA ratio ranging from 1.131 to 2.029 (approximately 13-19 days). The methane content in the biogas produced from the digesters was 7% on day 9 and increased rapidly until approximately day 27 (approximately 72%). In experimental condition 2, biogas yield was improved when the feed to microorganism ratio exceeded 0.6, with an initial lag-phase. Conclusions: Even if the TVFA/TA ratio was greater than 1.0, the biogas production was processed continuously, and the $CO_2$ content of the biogas production was as high as 60%. The biogas yield was improved when the F/M ratio was increased more than 0.6, but the lag-phase of carbohydrate-based material digestion became longer starting with high organic loading rate. To clarify the problem of the initial lag-phase, our future study will examine the microbial mechanisms during anaerobic digestion.

• Korean Journal of Ecology and Environment
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• v.49 no.2
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• pp.67-79
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• 2016

Cyanotoxins in aquatic ecosystems have been investigated by many researchers worldwide. Cyanotoxins can be classified according to toxicity as neurotoxins (anatoxin-a, anatoxin-a(s), saxitoxins) or hepatotoxins (microcystins, nodularin, cylindrospermopsin). Microcystins are generally present within cyanobacterial cells and are released by damage to the cell membrane. Cyanotoxins have been reported to cause adverse effects and to accumulate in aquatic organisms in lakes, rivers and oceans. Possible pathways of microcystins in Lake Suwa, Japan, have been investigated from five perspectives: production, adsorption, physiochemical decomposition, bioaccumulation and biodegradation. In this study, temporal variability in microcystins in Lake Suwa were investigated over 25 years (1991~2015). In nature, microcystins are removed by biodegradation of microorganisms and/or feeding of predators. However, during water treatment, the use of copper sulfate to remove algal cells causes extraction of a mess of microcystins. Cyanotoxins are removed by physical, chemical and biological methods, and the reduction of nutrients inflow is a basic method to prevent cyanobacterial bloom formation. However, this method is not effective for eutrophic lakes because nutrients are already present. The presence of a cyanotoxins can be a potential threat and therefore must be considered during water treatment. A complete understanding of the mechanism of cyanotoxins degradation in the ecosystem requires more intensive study, including a quantitative enumeration of cyanotoxin degrading microbes. This should be done in conjunction with an investigation of the microbial ecological mechanism of cyanobacteria degradation.

• Journal of the Korea Organic Resources Recycling Association
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• v.14 no.4
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• pp.141-150
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• 2006

To develop the microbial agents for the environmentally-friendly treatment and recycling of food waste, useful microorganisms, which showed higher degradation activities to various organic compounds and possessed flocculating activities, were isolated from the earthworm. One of the isolated strains, named JS-01, was further selected due to its higher flocculating activity against 0.5% Kaolin clay. JS-01 was identified as Bacillus pumilus sp. by 16s rDNA analysis. The optimal temperature and pH for the growth of JS-01 to express the flocculating activity was found to be at $37^{\circ}C$ in pH 7.0 of EPS broth medium. JS-01 also expressed good degrading activity against cellulose, which is one of the representative organic materials in food waste. We propose that JS-01 will be a good candidate for the efficient treatment of food waste and leachate due to the property to degrade cellulose and flocculating activity.

• Journal of the Korea Organic Resources Recycling Association
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• v.16 no.3
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• pp.46-51
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• 2008

The traditional view of the fate of lignin under anaerobic conditions is that it is recalcitrant because molecular oxygen is required for depolymerization. The presence of lignin is apparently the most important factor affecting the biodegradability of ligneous materials. The initial step in the degradation of ligneous material to smaller intermediates is catalyzed by enzymes secreted by microorganisms and is generally regarded as the rate limiting step in the microbial mineralization of organic matter. Biochemical methane potential (BMP) test, typically used to assess anaerobic biodegradability of liquid wastes with added nutrients and bacteria, have been adapted to assess initial biodegradation of ligneous material under anaerobic conditions. A method based on selective inhibition of microorganism activity, by 3% toluene, has been used to measure using the initial degradation rate of ligneous material and the accumulation of lignin-derived compounds.