Seog-Jin Kang

Autophagy induced by resveratrol prevents human prion protein-mediated neurotoxicity.

Our previous study revealed that resveratrol blocks prion protein peptide PrP(106-126)-induced neurotoxicity. However, the mechanism of resveratrol-mediated neuroprotection in prion diseases is not clear. Resveratrol initiates neuroprotective effects via the activation of autophagy, which protects organelles, cells, and organisms against misfolded protein-disorders, including Alzheimers disease and Parkinsons disease via regulation of mitochondrial homeostasis. Thus, we focused on elucidating the mechanisms responsible for resveratrol-mediated neuroprotection related to mitochondrial homeostasis as a result of autophagy activation. Resveratrol prevented PrP(106-126)-induced neuronal cell death by activating autophagy. Moreover, resveratrol-induced autophagy prevented the PrP(106-126)-induced reduction in mitochondrial potential and translocation of Bax to the mitochondria and cytochrome c release. Our results indicate that treatment with resveratrol appears to protect against neurotoxicity caused by prion protein peptides and the neuroprotection is induced by resveratrol-mediated autophagy signals.

Lactoferrin protects against prion protein-induced cell death in neuronal cells by preventing mitochondrial dysfunction

Prion disorder-related neurodegenerative diseases are characterized by the accumulation of prion protein (PrP) scrapie isoform (PrPsc) within the central nervous system. PrPsc induces neuronal cell death by increasing intracellular generation of reactive oxygen species (ROS). Lactoferrin (LF) is an 80 kDa protein, which has antioxidant abilities due to the scavenging of ROS. The effects of LF treatment on PrP (106-126)-mediated neurotoxicity and ROS generation were the focus of this study. LF treatment protected against PrP (106-126)-induced neuronal cell death and decreased ROS generation. The reduced ROS generation prevented PrP (106-126)-induced mitochondrial dysfunction. Moreover, PrP (106-126)-induced protein activation including c-Jun N-terminal kinase and caspase-3 were blocked by LF treatment. These results demonstrated that LF protects neuronal cells against PrP (106-126)-mediated neurotoxicity through the scavenging of ROS and provide evidence that LF treatment prevents neuronal cell death caused by PrP (106-126).

Evaluation of Fertilizer Value of Animal Cadavers for Agricultural Recycling

To evaluate fertilizer value of animal cadavers for agricultural recycling, fertilizer components of animal cadavers by pig and poultry were investigated using rendering and alkali (KOH) treatment methods. Total nitrogen concentrations in meat waste by pig and poultry using rendering treatment method were 7.80% and 9.30%, respectively. Total nitrogen concentration in meat waste of pig by KOH treatment method was lower than that by rendering treatment method. Organic matter concentrations in meat waste of pig and poultry ranged 87.8~97.4%. Total phosphorus concentrations in bone waste of pig using rendering and KOH treatment methods ranged 5.59~11.18%. Animal cadavers contains nitrogen, phosphorus, potassium and other nutrients essential to plant growth. The results of this study suggest that animal cadavers can supply some of the nutrient requirements of crops and is a valuable fertilizer as well.

Evaluation of Possibility of Water Plant Wastes in Composting for Agricultural Recycling

To evaluate the possibility of water plant wastes in composting for agricultural recycling, Phragmites communis (PHRCO), Typha orientalis (TYHOR) and Zizania latifolia (ZIZLA) were used as a compost materials. In composting basin, cumulative oxygen consumptions of the compost used by water plant wastes were rapidly increased at the early stage and slightly decreased in around 15 days. Cumulative oxygen consumptions under different water plant wastes were higher in the order of TYHOR > ZIZLA > PHRCO. Temperature changes during composting process were rapidly increased at the early stage and then slowly decreased to . The maximum temperatures were higher in the order of ZIZLA ( at 11 days after starting composting) > TYHOR ( at 10 days after starting composting) > PHRCO ( at 7 days after starting composting). Oxygen consumptions at maximum temperature were higher in the order of TYHOR () > ZIZLA () > PHRCO (). Organic matter contents, moisture contents and OM/N rates in the compost ranged 39.5~44.8%, 29.6~35.6% and 27.9~32.9, respectively. Considering that water plant waste can supply some of the nutrient requirements of crops and is a valuable fertilizer.

Degradation Rate and Velocity under Different Acidic and Alkaline Degradation Agents for Liquid Fertilizer of Rendering By-product

In order to develop liquid fertilizer using rendering by-product, rates and velocities of degradation from rendering by-product using pig cadaver investigated under different amount of injection and time with degradation agents (KOH, NaOH, and ). The amount of residue by degradation agent of treatment method was higher than that in KOH, NaOH and treatment methods. The degradation velocities (K; ) of rendering by-product in KOH treatment method were higher in the order of 25% () > 30% () > 20% () > 15% () > 10% () of weight of rendering by-product. In all conditions, the degradation velocity of rendering by-product using 30% of weight of rendering by-product was rapid than that for KOH, NaOH and treatment methods. Degradation rates of rendering by-product using NaOH were similar to that of KOH and except for under injecting 25% and 30% of rendering by-product weight.

The prevalence and genetic characteristics of porcine circovirus type 2 and 3 in Korea

BackgroundPorcine circovirus-associated diseases (PCVAD), caused by porcine circovirus type 2 (PCV2), threaten the pig industry worldwide. Five genotypes of PCV2 were recently identified: PCV2a, PCV2b, PCV2c, PCV2d and PCV2e. In addition, a novel porcine circovirus from a case of a sow with dermatitis, nephropathy syndrome and reproductive failure has been identified based on metagenomic analysis and classified as porcine circovirus type 3 (PCV3). Therefore, the current study was conducted to determine the prevalence and genetic characteristics of PCV2 and PCV3 in clinical samples.ResultsA total of 471 samples (161 tissue samples of lungs and lymph nodes from 34 farms and 310 serum samples from 47 farms) were tested for PCV2. Among them, 171 samples from 59 farms that had been positive for PCV2 were genotyped. Another 690 samples (296 tissue samples of lungs and lymph nodes from 91 farms, 108 samples of aborted foetuses from 26 farms, and 286 serum samples from 47 farms) were tested for PCV3. Based on PCV2 genotyping results, PCV2d was the most prevalent genotype (107 of 171 samples), and co-infections with combinations of PCV2a, 2b and 2d were identified in 48 samples from 17 farms. A total of 14 samples from 11 farms were also positive for both PCV2 and PCV3. For PCV3, 57 samples (9.8%) from 32 farms (23.2%) were positive. Among the 108 aborted foetuses from 26 farms, only 2 samples were positive for PCV3. Based on sequence comparisons, PCV2d shares 89.6–91.0% and 93.2–94.3% homology with PCV2a and PCV2b, respectively; 98.6–100% homology is shared among PCV2d strains. The PCV3 strains identified in this study share 98.0–99.5% homology.ConclusionsOur study concludes that PCV2d has become the most predominant genotype in Korea. PCV3 was also identified in clinical samples, though no significant association with clinical symptoms was observed in PCV3-positive cases.

Liquid-Composting Conditions of By-product Obtained from Degradation of Animal Carcass for Agriculture Recycling

BACKGROUND: Globally, concern about emerging infectious diseases of livestock is growing. For the disposal of the animal carcass, it is necessary to recycle the carcass into an agriculturally usable product. The objective of this study was to investigate the composting conditions of liquid by-product obtained from degradation of animal carcass. METHODS AND RESULTS: Optimum conditions of liquid fertilizer were investigated using different microorganisms, pHs, and volumes of microorganisms (Lactobacillus rhamnosus+Pichia deserticola). Based on the results from the optimum conditions, compost maturity and quality of liquid fertilizer were evaluated for 112 days. The compost maturity of liquid fertilizer were higher in the order of LP(Lactobacillus rhamnosus + Pichia deserticola) > BC(Bacillus cereus) > BS(Bacillus subtilis). The optimum condition under different volumes of LP was injection of 0.5 mL/100 mL. The compost maturity under different pHs were higher in the order of pH 7 > . The liquid by-product at 56 days after composting was completely decomposed. The concentrations of T-N, T-P and in liquid fertilizer at 56 days were 0.94, 0.17 and 3.78%, respectively, and the sum of those concentrations was 4.89%. CONCLUSION(S): Liquid fertilizer of by-product using pig carcass was decomposed with optimum conditions(LP, pH 7, injection of 0.5 mL/100 mL) in 56 days after composting, and was suitable for official standard of commercial fertilizer.

Effect of Sawdust Mixing Ratio on Composting of Animal Cadaver Residue Using Rendering Treatment Method

In order to obtain optimum mixing conditions with animal cadaver residue and sawdust for composting using rendering treatment method for agricultural recycling, changes of chemical characteristics and compost quality after composting were investigated. Initial mixing ratios with animal cadaver residue and sawdust were adjusted 100 : 0, 50 : 50 and 30 : 70. Temperature, pH, contents of ammonia and carbon dioxide were rapidly increased in 3 days and then decreased with time. Organic matter content was similar in all conditions. In mixing ratio of 50 : 50, the compost quality was satisfied with compost depending on official standard for product fertilizer. Thus, the optimum mixing ratio of animal cadaver residue and sawdust were 50 : 50.