We attempted to investigate antibacterial and proteolytic activities of bacteria isolated from three ethnic fermented seafoods in the east coast of South Korea, gajami sikhae, squid jeotgal, and fermented jinuari (Grateloupia filicina). Bacillus cereus ATCC 14579, Listeria monocytogenes ATCC 15313, Staphylococcus aureus KCTC 1916, Escherichia coli O157:H7 ATCC 43895, and Salmonella enterica serovar Typhimurium ATCC 4931 were selected to determine the antibacterial activity of the bacterial isolates. Among 233 isolates from the three foods, 36 isolates (15.5%) showed antibacterial activity against B. cereus ATCC 14579, the highest incidence of inhibition, followed by S. aureus KCTC 1916 (7.7%) and L. monocytogenes ATCC 15313 (6.0%). However, only five and three strains among the isolates exhibited inhibitory activity against Gram-negative indicators, E. coli ATCC 43895 and Sal. enterica ATCC 4931, respectively. The proteolytic activity of the isolates was determined via hydrolysis of skim milk after 24, 48, and 72 h incubation. After 72 h incubation, 72 out of 233 isolates (30.9%) showed proteolytic activity, and the isolates of fermented jinuari exhibited the highest incidence of proteolytic activity (60%, 36 isolates). These results suggest that ethnic fermented seafoods in the east coast of South Korea might be a promising source of bacterial strains producing antibacterial and proteolytic compounds.

Proteolytic enzymes were screened to obtain anchovy protein hydrolysates (APH) with low-bitterness under pressurization. First, the residual proteolytic activity (%) and SDS-PAGE of commercially available food-grade protease (Alcalase® 2.4 L, FlavourzymeTM 500 MG, Neutrase®, ProtamexTM) and mixed enzyme (ME, Alcalase® : FlavourzymeTM = 1 : 5) after treatments of ambient pressure and 100 MPa at 50oC were investigated. The proteolytic activity of enzymes was still largely retained after pressure treatment. The SDS-PAGE on tested enzymes showed that the electrophoretic mobility maps (EMMs) after pressure treatment were similar to those at ambient pressure. With these results, it seemed that tested enzymes were stable at 100 MPa and 50oC. Raw anchovy hydrolyzed with various protease at 50oC under ambient pressure and 100 MPa for 1, 2, 6, 12, and 24 h. The degree of hydrolysis (DH, %) of prepared APHs at 100 MPa was increased, which suggests that the medium pressure treatment accelerates protein hydrolysis. The APH by ME exhibited the best suitable characteristics, which had a relatively higher DH (36.2±1.8- 57.5±2.8), a high content of oligopeptides with a molecular mass lower than 1,100 Da, mildly bitter taste as the bitterness value was lower than that of 0.2 g/L tea alkaloid, and the lowest contents of tryptophan. Thus, ME was selected to obtain APH with low-bitterness under pressurization.

오징어 젓갈에 오징어 먹즙을 2% 및 4% 농도로 첨가하고 10℃에서 8주일간, 20℃에서 32일간 숙성시키면서 아미노태 질소와 근육단백질 변화를 분석한 결과는 다음과 같다. 오징어 먹즙이 첨가되지 않은 오징어 젓갈의 아미노태 질소는 식염 농도가 낮고 숙성온도가 높을수록 숙성 후반까지 계속 유의성 높게 증가하여 숙성이 촉진되었으며 오징어 근육의 단백질 변화는 myosin heavy chain이 숙성 초반에 현저히 분해되지만 actin의 변화는 거의 없어서 protease에 강하였다. 오징어 먹즙을 첨가한 오징어 젓갈의 아미노태 질소 함량은 숙성후반까지 계속 증가하였으나 증가폭은 무 첨가군에 비하여 적었으며 오징어 근육 단백질 중 myosin heavy chain은 숙성 중반에 현저히 분해되었으며 식염농도가 높고, 온도가 낮은 먹즙 첨가군은 분해 속도가 느렸다.

Nine strains of pathogenic Vibrio sp. of clinical and environmental origin were examined for the degradation of gelatin, casein and hemolysin which is important to the virulence of this bacterium. Culture filtrates of all nine strains of Vibrio exhibited proteolytic activities. Especially, four strains of V. parahaemolyticus and one V. alginolyticus showed strong gelatin-degrading activity. In terms of hemolytic activity, three V. parahaemolyticus and V. mimicus showed strong β-hemolysis whereas those of strains of V. alginolyticus, V. fluuialis, V. uulnificus examined lacked this activity.

Plant growth under water-deficit conditions adversely affects many key processes. Efforts to understand drought stress-related defense mechanisms have revealed a host of plant genes using molecular approaches in rice. Here, we report the novel finding that OsCTR1 E3 ligase regulates both chloroplast-localized chloroplast protein 12 (OsCP12) and ribosomal protein 1 (OsRP1) in protein levels and subcellular localization. The results of a yeast-two hybrid assay, bimolecular fluorescence complementation assay, ubiquitination assay, subcellular localization, and a protein degradation assay support the hypothesis that OsCTR1 functions in trafficking inhibition and proteolysis of OsCP12 and OsRP1 via the ubiquitin 26S proteasome pathway. Heterogeneous overexpression of OsCTR1 in Arabidopsis showed ABA-hypersensitive phenotype in seed germination, seedling growth, and stomatal closure. The transgenic plants also exhibited improvement of water-deficit tolerance with an accumulation of hydrogen peroxide production. These results demonstrate that the OsCTR1 E3 ligase might positively regulate the cellular functions of OsCP12 and RP1 related to photosynthesis under drought stress conditions in rice.

반응표면분석법을 이용하여 가수분해 조건에 콩 가수분해물의 품질 특성을 모니터링 하였다. 수율은 protease 농도에 크게 영향을 받았으며, 이상의 농도에서는 가수분해 시간의 영향이 점차 증가하였다. 수율에 대한 회귀식의 는 0.978로서 이내에서 유의성이 인정되었다 가용성고형분은 pretense첨가량과 가수분해시간의 영향이 모두 나타났으며, 회귀식의 는 0.954로서 이내에서 유의성이 인정되었다. 가수분해도는 pretense첨가량이 높을수