Thrombin-induced platelet microbicidal proteins (tPMP) are antibacterial proteins released when platelets are stimulated by thrombin. It has been reported that tPMP has antibacterial activity against various bacterial species including causative agents of infective endocarditis. Most of the oral streptococci have resistance to the killing by tPMP and this fact may play an important role as a virulence factor in infective endocarditis. However, the susceptibility and resistance mechanism of oral streptococci for tPMP have not been revealed yet. In this study, the killing mechanism of tPMP for oral streptococci has been investigated. Streptococcus rattus BHT, a susceptible strain, and Streptococcus gordonii DL1, a resistant strain, have been used in this study. tPMP was isolated from platelet after stimulation with thrombin. Cell membrane depolarization was examined with 3,3'-dipropylthiodicarbocyanine iodide (DiSC₃), membrane potential-sensitive cyanine dye, by fluorescence spectrophotometry. The permeabilization of cell membrane by tPMP was investigated with propidium iodide (PI) by flow cytometry. tPMP susceptible S. rattus BHT showed the increase of the DiSC₃fluorescence level meaning depolarization of cell membrane and increase of the uptake of PI which means permeabilization of cell membrane. However, tPMP resistant S. gordonii DLI did not show depolarization and permeabilization. These results indicate that the increasing depolarization and permeabilization of oral streptococcal cell membrane are associated with the bactericidal activity of tPMP.

프로테오믹스 기법을 이용하여 벼 저온 스트레스 관련 단백질을 분리 동정하기 위하여 저온 처리한 벼로부터 단백질을 분리하였다. 분리한 단백질로부터 Rubisco 단백질을 제거하기 위해 PEG fractionation을 실시한 후 PEG 상등액과 pellet 분획을 각각 이차원전기 영동으로 단백질을 분석하였고, MALDI-TOF MS를 이용하여 단백질을 동정하였다. PEG 상등액에서 8개의 단백질 spot이 증가하였고 10개의 spot 이 감소하였다. 증가

본 연구는 한우 난포란이 체외성숙된 환경의 변화를 단백질 측면으로부터 검토하기 위하여 체외성숙 배지와 세포질내 단백질 변화와 종류를 검토하였다. 그 결과 배지 내의 단백질 발현량은 배양 4.5시간째까지 감소하였고, 배양 13.5시간째까지는 변화가 없었다. 그러나 배양 13.5~18시간 사이에 증가한 후 배양 18시간 이후에 다시 감소하는 경향이었다. 세포질내의 단백질 발현량은 배양 4.5시간째까지 증가하였고 배양 9시간째까지 급격히 감소하였다. 배양 9시간째부터 18시간째 까지는 단백질 발현량이 유사한 경향이었으나 배양 18시간째부터 24시간째까지 다시 증가하였다. 한편 체외성숙한 배지와 세포질을 2차원 전기영동하여 각각 298개 및 35개의 단백질 spot을 확인하였고, 그 중 배지에서는 28개, 세포질에서는 5개의 spot이 유의적인 변화를 확인하였다. 이들 spot 대한MALDI-TOP분석으로 배지와 세포질에서 각각 8개 및 1개의 단백질을 동정하였다. 그 종류는 aldose reductase, alpha enolase, apolipoprotein A-1 precursor, 43M1a collectin precursor, heat shock 27kDa protein, plasminogen activator inhibitor-1 precursor, thrombospondin 1 transitional endoplasmic reticulum ATPase 및 β-tubulin이었다.

Somatic cell nuclear transfer in cattle has limited efficiency in terms of production of live offspring due to high incidence of fetal failure after embryo transfer to recipients. Such low efficiency of cloning could possibly arise from abnormal and poorly developed placenta. In the present study the placental proteome in late pregnancy established from in vitro fertilization (IVF) and nuclear transfer (NT) was analysed. Proteome alternation was tested using two-dimensional polyacrylamide gel electrophoresis (2-DE) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI- TOF). Comparing placenta from NT embryos to those from IVF counterparts, significant changes in expression level were found in 18 proteins. Of these proteins 12 were not expressed in NT placenta but expressed in IVF counterpart, whereas the expression of the other 6 proteins was limited only in NT placenta. Among these proteins, cytokeratin 8 and vimentin are considered to be involved in regulation of post-implantation development. In particular, cytokeratin 8 and vimentin may be used as makers for placental development during pregnancy because their expression levels changed considerably in NT placental tissue compared with its IVF counterpart. Data from 2-DE suggest that protein expression was disorientated in late pregnancy from NT, but this distortion was eliminated with progression of pregnancy. These findings demonstrate abnormal placental development during late pregnancy from NT and suggest that alterations of specific placental protein expression may be involved in abnormal function of placenta.

To investigate the antifungal activity related protein in pesticidal bacteria, a bacterial strain LTD was isolated from soil collected at Gimje in Jeonbuk province, Korea, and identified as Bacillus subtilis LTD based on a API50 CHB kit and 168 rDNA seque