Dear Editor,Chemotherapy remains ineffective against solid tumors due to their dense extracellular matrix, abnormal vasculature, and high interstitial pressure coalesce to create a barrier to drug penetration and dist...Dear Editor,Chemotherapy remains ineffective against solid tumors due to their dense extracellular matrix, abnormal vasculature, and high interstitial pressure coalesce to create a barrier to drug penetration and distribution. This challenge is even particularly pronounced in pancreatic and brain tumors, where chemotherapy response rates remain dismal.The advent of ultrasonic tumor permeabilization using focused ultrasound and microbubble technology represents a significant breakthrough in research on overcoming drug resistance in solid tumors toward overcoming these barriers and improving outcomes.[1]展开更多
Objective:To investigate the mechanism of antibacterial activity of luteoiin(LUT) against methicillin-resistant Staphylococcus aureus(MRSA).Methods:The mechanism of anti-MRSA activity of LUT was analyzed by the viabil...Objective:To investigate the mechanism of antibacterial activity of luteoiin(LUT) against methicillin-resistant Staphylococcus aureus(MRSA).Methods:The mechanism of anti-MRSA activity of LUT was analyzed by the viability assay in membrane permeabilizing agent ATPase inhibitors,and peptidoglycan(PGN) derived from Staphylococcus aureus(S.aureus).Also,transmission electron microscopy was used to monitor survival characteristics and changes in S.aureus morphology.Results:Compared to the LUT alone,the optical density of suspensions treated with the combination of 125 μg/mL Tris and 230 μg/mL DCCD were reduced to 60%and 46%,respectively.PGN(15.6 μg/mL) gradually impeded the activity of LUT,and PGN(62.5 μg/mL) completely blocked the activity of LUT on S.aureus.Conclusions:Increased susceptibility to LUT with me Tris and DCCD combinations is evident in all tested MRSA isolates.The results indicate LUT synergy in increasing cytoplasmic membrane permeability and inhibiting ATPase.S.aureus PGN directly blocks the antibacterial activity of LUT,suggesting the direct binding of LUT with PGN.These findings may be validated for the development of antibacterial agent for low MRSA resistance.展开更多
The increased importance of the G. mellonella for wide range of scientific research and commercial sides will need to create a germplasm resource banking by cryopreservation. Impermeability is a fundamental limiting f...The increased importance of the G. mellonella for wide range of scientific research and commercial sides will need to create a germplasm resource banking by cryopreservation. Impermeability is a fundamental limiting factor for the successful cryopreservation of arthropods embryos. The successful permeability of Drosophila embryo by using an embryo permeabilization solvent (EPS) solution encouraged this trial on G. mellonella embryos (stage of 24 hours Post-oviposition (h PO)). Permeability assessment with Rhodamine B and crystal violet dyes showed that G. mellonella embryos can be permeabilized by EPS of D-limonene that has 3 mol ethoxylated alcohol. The permeabilization for 30 sec exposure time was resulted 61.5% ± 5.8% survival rate, 31.7% ± 3.1% uptakes dyes and 40.5% ± 0.3% was the survival rate post loading in 12% Ethylene glycol (EG). The low viability after immersion in liquid nitrogen (LN) (0.6% ± 0.08%) is due to the dual toxicity of EPS and cryoprotectant (CPA) solutions. However, fluorescence images showed sufficient permeability that confirms the possibility to increase the permeability of G. mellonella embryos with EPS solution, and to have the opportunity to improve the viability after LN by improving procedures of loading and dehydration with various CPAs and exposure times, which decrease the toxicity effect.展开更多
We reported previously that chymotrypsin B is cached in the lysosomes of rat hepatocytes and mediates apoptosis induced by TNF-alpha (1) and H2O2. However, the mechanism
D-psicose exits in an extremely small amount in nature and is difficult to be chemically synthesized.Only three bacteria have been used in the biotransformation of D-psicose from D-fructose.In this paper,another bacte...D-psicose exits in an extremely small amount in nature and is difficult to be chemically synthesized.Only three bacteria have been used in the biotransformation of D-psicose from D-fructose.In this paper,another bacterium which could convert D-fructose to D-psicose was isolated and identified as Rhodobacter sphaeroides.The process parameters of D-psicose production using permeabilized cells of Rhodobacter sphaeroides SK011 were optimized,including the permeabilization procedure:0.1%(w/v)CTAB,10 min,and reaction conditions:cell concentration,30 g dry cell wt/L;concentration of substrate,50 g/L;40℃,pH 9.0;reaction time,8 h.Under the optimized conditions,the permeabilized cells produced approximately 6.5 g/L D-psicose with a Dpsicose productivity of 0.82 g·L^(-1)·h^(-1).This is the first report of bioproduction of D-psicose using permeabilized cells of Rhodobacter sphaeroides.展开更多
The permeabilization of liposomes by melittin,an antimicrobial peptide(AMP),has been studied by an electrochemiluminescence(ECL)imaging strategy.The methodology consisted ffrst of encapsulating ECL reagents in sealed ...The permeabilization of liposomes by melittin,an antimicrobial peptide(AMP),has been studied by an electrochemiluminescence(ECL)imaging strategy.The methodology consisted ffrst of encapsulating ECL reagents in sealed giant asymmetrical liposomes(100μm in diameter)made of DOPG/DOPC phospholipids(i.e.,1,2-dioleoyl-sn-glycerol-3-phospho-(1′-rac-glycerol)sodium salt/1,2-dioleolyl-sn-glycero-3-phosphocholine).Then liposomes were placed on an indium tin oxide electrode coated with poly-L-lysine to avoid any membrane poration/permeabilization through polarization of the electrode surface.Finally,the addition of melittin(from 10μM to 100 nM in concentration)enabled the permeabilization of the lipid membrane followed by the liposome content release and subsequent light generation through the ECL reagents oxidation processes.Interestingly,at a melittin concentration of 10μM,two successive leakages occurring on the same liposome could be imaged.Combination of ECL and photoluminescence imaging allowed comprehensive monitoring of the permeabilization and content release of a single liposome.This ECL imaging approach opens interesting perspectives to characterize the instant release of vesicle content upon permeabilization by AMPs or other membrane-active species.展开更多
文摘Dear Editor,Chemotherapy remains ineffective against solid tumors due to their dense extracellular matrix, abnormal vasculature, and high interstitial pressure coalesce to create a barrier to drug penetration and distribution. This challenge is even particularly pronounced in pancreatic and brain tumors, where chemotherapy response rates remain dismal.The advent of ultrasonic tumor permeabilization using focused ultrasound and microbubble technology represents a significant breakthrough in research on overcoming drug resistance in solid tumors toward overcoming these barriers and improving outcomes.[1]
基金supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Educatio(2013060380)+2 种基金the Korea governmen(MSIP)(2008-0062484)Cooperative Research Program for Agriculture Science&Technology Development(Project No.PJ00962201)Rural Development Administration,Republic of Korea
文摘Objective:To investigate the mechanism of antibacterial activity of luteoiin(LUT) against methicillin-resistant Staphylococcus aureus(MRSA).Methods:The mechanism of anti-MRSA activity of LUT was analyzed by the viability assay in membrane permeabilizing agent ATPase inhibitors,and peptidoglycan(PGN) derived from Staphylococcus aureus(S.aureus).Also,transmission electron microscopy was used to monitor survival characteristics and changes in S.aureus morphology.Results:Compared to the LUT alone,the optical density of suspensions treated with the combination of 125 μg/mL Tris and 230 μg/mL DCCD were reduced to 60%and 46%,respectively.PGN(15.6 μg/mL) gradually impeded the activity of LUT,and PGN(62.5 μg/mL) completely blocked the activity of LUT on S.aureus.Conclusions:Increased susceptibility to LUT with me Tris and DCCD combinations is evident in all tested MRSA isolates.The results indicate LUT synergy in increasing cytoplasmic membrane permeability and inhibiting ATPase.S.aureus PGN directly blocks the antibacterial activity of LUT,suggesting the direct binding of LUT with PGN.These findings may be validated for the development of antibacterial agent for low MRSA resistance.
文摘The increased importance of the G. mellonella for wide range of scientific research and commercial sides will need to create a germplasm resource banking by cryopreservation. Impermeability is a fundamental limiting factor for the successful cryopreservation of arthropods embryos. The successful permeability of Drosophila embryo by using an embryo permeabilization solvent (EPS) solution encouraged this trial on G. mellonella embryos (stage of 24 hours Post-oviposition (h PO)). Permeability assessment with Rhodamine B and crystal violet dyes showed that G. mellonella embryos can be permeabilized by EPS of D-limonene that has 3 mol ethoxylated alcohol. The permeabilization for 30 sec exposure time was resulted 61.5% ± 5.8% survival rate, 31.7% ± 3.1% uptakes dyes and 40.5% ± 0.3% was the survival rate post loading in 12% Ethylene glycol (EG). The low viability after immersion in liquid nitrogen (LN) (0.6% ± 0.08%) is due to the dual toxicity of EPS and cryoprotectant (CPA) solutions. However, fluorescence images showed sufficient permeability that confirms the possibility to increase the permeability of G. mellonella embryos with EPS solution, and to have the opportunity to improve the viability after LN by improving procedures of loading and dehydration with various CPAs and exposure times, which decrease the toxicity effect.
文摘We reported previously that chymotrypsin B is cached in the lysosomes of rat hepatocytes and mediates apoptosis induced by TNF-alpha (1) and H2O2. However, the mechanism
基金supported financially by the National High Technology Research and Development Program of China(Grant No.2006AA10Z334)the Research Program of Sate Key Laboratory of Food Science and Technology,Jiangnan University(SKLF-MB-200804 and SKLF-TS-200805).
文摘D-psicose exits in an extremely small amount in nature and is difficult to be chemically synthesized.Only three bacteria have been used in the biotransformation of D-psicose from D-fructose.In this paper,another bacterium which could convert D-fructose to D-psicose was isolated and identified as Rhodobacter sphaeroides.The process parameters of D-psicose production using permeabilized cells of Rhodobacter sphaeroides SK011 were optimized,including the permeabilization procedure:0.1%(w/v)CTAB,10 min,and reaction conditions:cell concentration,30 g dry cell wt/L;concentration of substrate,50 g/L;40℃,pH 9.0;reaction time,8 h.Under the optimized conditions,the permeabilized cells produced approximately 6.5 g/L D-psicose with a Dpsicose productivity of 0.82 g·L^(-1)·h^(-1).This is the first report of bioproduction of D-psicose using permeabilized cells of Rhodobacter sphaeroides.
基金supported in parts by CNRS UMR 8640,Ecole Normale Supérieure,PSL University and Sorbonne Université.F.B.T.thanks the doctoral school ED388“Chimie Physique et de Chimie Analytique de Paris Centre”for a PhD grant.We thank Gilles Clodic(MS3U platform,Sorbonne Université)for MALDI-TOF mass spectrometry analysis.N.S.acknowledges the financial support from Agence Nationale de la Recherche(ELISE-ANR-21-CE42).
文摘The permeabilization of liposomes by melittin,an antimicrobial peptide(AMP),has been studied by an electrochemiluminescence(ECL)imaging strategy.The methodology consisted ffrst of encapsulating ECL reagents in sealed giant asymmetrical liposomes(100μm in diameter)made of DOPG/DOPC phospholipids(i.e.,1,2-dioleoyl-sn-glycerol-3-phospho-(1′-rac-glycerol)sodium salt/1,2-dioleolyl-sn-glycero-3-phosphocholine).Then liposomes were placed on an indium tin oxide electrode coated with poly-L-lysine to avoid any membrane poration/permeabilization through polarization of the electrode surface.Finally,the addition of melittin(from 10μM to 100 nM in concentration)enabled the permeabilization of the lipid membrane followed by the liposome content release and subsequent light generation through the ECL reagents oxidation processes.Interestingly,at a melittin concentration of 10μM,two successive leakages occurring on the same liposome could be imaged.Combination of ECL and photoluminescence imaging allowed comprehensive monitoring of the permeabilization and content release of a single liposome.This ECL imaging approach opens interesting perspectives to characterize the instant release of vesicle content upon permeabilization by AMPs or other membrane-active species.
