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Choco Michael Gorospe,Sang-Hyun Han,Seong Geun Kim,Joo Young Park,Chang-Ho Kang,정진훈,소재성 한국생물공학회 2013 Biotechnology and Bioprocess Engineering Vol.18 No.5
We examined the effectiveness of using different calcium salts for bioconsolidation. Four calcium salts were chosen based on their applicability and solubility. Initial experiments demonstrated that the addition of any calcium salt had a negative effect on the urease activity of S. pasteurii. Microscopic examinations elucidated the morphological and structural differences of the calcium carbonate (CaCO3) crystals induced. Calcite and vaterite are the prominent forms of CaCO3 detected according to X-ray diffraction (XRD) analysis. Bioconsolidated sand samples were able to significantly resist water flow through a column compared to the non-treated samples. Also, in a tightness test, the differences in the ability to retain water within columns were observed among the samples tested. Moreover, despite the differences, the calcium salts tested still bound the sand together to form blocks. Our results further explain the influence of multiple factors in crystal formation and sand bioconsolidation effectiveness.
Leucine supplementation mimics the effects of caloric restriction on yeast chronological lifespan
Gorospe Choco Michael,Jemiseye Olumide Temitayo,이성근 대한독성 유전단백체 학회 2022 Molecular & cellular toxicology Vol.18 No.1
Backgrounds Leucine prototrophic yeast exhibits extended longevity and related phenotypes similar to yeast grown under calorie restriction (CR) condition. The extended longevity of leucine prototrophic yeast is thought to be a function of abundant cellular leucine level. Objective To verify the similar effects of leucine-induced and CR-induced chronological life span (CLS), leucine prototrophic and auxotrophic yeast cells were grown in the presence or absence of exogenous leucine supplementation and CR condition, and their lifespan and various phenotypes were examined. Results Leucine supplementation induced CLS extension, increased cellular Cox2p levels, and decreased cell death. These phenotypes were similar to those of the cells grown under CR. Interestingly, simultaneous treatment with exogenous leucine supplementation and CR led to a synergistic effect. CLS and cellular Cox2p levels increased further by simultaneous treatment compared to the observations in cells treated with either leucine supplementation or CR. Similarly, the rate of cell death of simultaneously treated cells was signifi cantly lower than that of cells undergoing only one treatment. Conclusion Leucine-induced CLS extension and a decreased in the rate of cell death observed in this study verified the function of leucine in cell death prevention and CLS extension in yeast. Interestingly, leucine-induced changes were similar to CR-induced changes. The results in this study suggest that leucine can function as a CR mimetic.
Chronological lifespan increases of yeast by leucine supplementation
( Sung-lim Yu ),( Choco Michael Gorospe ),( Mi-sun Kang ),( Sung-keun Lee ) 한국장기요양학회 2018 한국장기요양학회 추계학술대회자료집 Vol.2018 No.-
Supplementation or depletion of some amino acids, such as methionine, threonine, and branched-chain amino acids (BCAA), has been identified to modulate life span and health span of many species. BCAA (leucine, valine, and isoleucine) supplementation was shown to promote yeast chronological life span (CLS). Previously, we showed that two leucine biosynthesis genes, LEU2 and LEU4, are critical in determining yeast lifespan. In order to understand the mechanism by which yeast lifespan is regulated in the connection to leucine metabolism, we have examined the effect of leucine supplementation on yeast CLS and the underlying mechanisms. Verification of cellular levels of cytochrome C oxidase and vital dye exclusion assay suggest that leucine supplementation increases yeast lifespan by alleviation of cell death rate.