Bacteriophages or more commonly ＂phages＂ are bacterial viruses. They are ubiquitous and good indicators of bacterial contaminations since their prevalence is high in those environments where their hosts are abundant...Bacteriophages or more commonly ＂phages＂ are bacterial viruses. They are ubiquitous and good indicators of bacterial contaminations since their prevalence is high in those environments where their hosts are abundant. Phage classification is based on morphology and for this reason, even though it is considered an old technique, TEM （Transmission Electron Microscopy） still plays a key role in their characterization. In the present work, the authors focused on TEM analysis of phage ФApr-1 isolated against Lactococcuslactis （L. lactis）, implicated in industrial fermentations and of phage ФIZSAM-1, active against Listeria monocytogenes （L. monocytogenes）, isolated from the environment. For observation with TEM （EM 900T-Zeiss）, phages were harvested in liquid media and were negative stained with fosfotungstic acid 2‰. An accurate viral ultrastructure analysis by using TEM is fundamental not only in the first approach of characterization of newly isolated phages but also for providing useful information to go further to the selection process as potential bio-decontaminants.展开更多
Fluoranthene, a four-ring polycyclic aromatic hydrocarbon that is possible genotoxic in nature, has been used as an indicator for assessing polycyclic aromatic hydrocarbon （PAH）-containing pollutants. Microbial degr...Fluoranthene, a four-ring polycyclic aromatic hydrocarbon that is possible genotoxic in nature, has been used as an indicator for assessing polycyclic aromatic hydrocarbon （PAH）-containing pollutants. Microbial degradation is one of the promising methods in removing up PAH-contaminated environments. White-rot fungi have showed the ability to degrade a wide range of PAHs. This study aimed to investigate enzyme production, fungal biomass, and glucose utilization during the biodegradation process of fiuoranthene by a white-rot fungus Pleurotus pulmonarius F043 and to identify the metabolites produced in the degradation process. The extracellular ligninolytic enzyme system of the fungi, producing laccases and peroxidases, was directly linked to the biodegradation of fiuoranthene. The production of ligninolytic enzymes during fluoranthene degradation was related to an increase in the biomass of Pleurotus pulmonarius F043. Fluoranthene removal decreased with an increase in fluoranthene concentrations. The highest biomass production of Pleurotus pulmonarius F043 （〉 4 400 mg L-1） was found in the 10 mg L-1 fluoranthene culture after 30 d of incubation. Two fluoranthene metabolites, naphthalene-l,8-dicarboxylic acid and phthalic acid, were found in the process of fluoranthene degradation. Laccase was revealed as the major enzyme that played an important role in degradation process. Suitable conditions must be found to promote a successful fungal biotransformation augmentation in liquid culture.展开更多
文摘Bacteriophages or more commonly ＂phages＂ are bacterial viruses. They are ubiquitous and good indicators of bacterial contaminations since their prevalence is high in those environments where their hosts are abundant. Phage classification is based on morphology and for this reason, even though it is considered an old technique, TEM （Transmission Electron Microscopy） still plays a key role in their characterization. In the present work, the authors focused on TEM analysis of phage ФApr-1 isolated against Lactococcuslactis （L. lactis）, implicated in industrial fermentations and of phage ФIZSAM-1, active against Listeria monocytogenes （L. monocytogenes）, isolated from the environment. For observation with TEM （EM 900T-Zeiss）, phages were harvested in liquid media and were negative stained with fosfotungstic acid 2‰. An accurate viral ultrastructure analysis by using TEM is fundamental not only in the first approach of characterization of newly isolated phages but also for providing useful information to go further to the selection process as potential bio-decontaminants.
基金supported by the Fundamental Research Grant Scheme(FRGS)of Ministry of Education,Malaysia(No.R.J130000.7809.4F465the Science Fund of Ministry of Science,Technology and Innovation,Malaysia(No.R.J130000.7909.4S110)
文摘Fluoranthene, a four-ring polycyclic aromatic hydrocarbon that is possible genotoxic in nature, has been used as an indicator for assessing polycyclic aromatic hydrocarbon （PAH）-containing pollutants. Microbial degradation is one of the promising methods in removing up PAH-contaminated environments. White-rot fungi have showed the ability to degrade a wide range of PAHs. This study aimed to investigate enzyme production, fungal biomass, and glucose utilization during the biodegradation process of fiuoranthene by a white-rot fungus Pleurotus pulmonarius F043 and to identify the metabolites produced in the degradation process. The extracellular ligninolytic enzyme system of the fungi, producing laccases and peroxidases, was directly linked to the biodegradation of fiuoranthene. The production of ligninolytic enzymes during fluoranthene degradation was related to an increase in the biomass of Pleurotus pulmonarius F043. Fluoranthene removal decreased with an increase in fluoranthene concentrations. The highest biomass production of Pleurotus pulmonarius F043 （〉 4 400 mg L-1） was found in the 10 mg L-1 fluoranthene culture after 30 d of incubation. Two fluoranthene metabolites, naphthalene-l,8-dicarboxylic acid and phthalic acid, were found in the process of fluoranthene degradation. Laccase was revealed as the major enzyme that played an important role in degradation process. Suitable conditions must be found to promote a successful fungal biotransformation augmentation in liquid culture.
