The Experts below are selected from a list of 9735 Experts worldwide ranked by ideXlab platform
Juhee Ahn - One of the best experts on this subject based on the ideXlab platform.
-
survival prophage induction and invasive properties of Lysogenic salmonella typhimurium exposed to simulated gastrointestinal conditions
Archives of Microbiology, 2014Co-Authors: Songrae Kim, Kanghee Ryu, Debabrata Biswas, Juhee AhnAbstract:This study was designed to evaluate the viability, prophage induction, invasive ability, and relative gene expression in Lysogenic Salmonella Typhimurium exposed to the simulated gastric juice (SGJ) at pH 2 (SGJ-2), 3 (SGJ-3), 4 (SGJ-4), and 5 (SGJ-5) for 30 min followed by 0.5 % bile salts for 2 h. The susceptibility of Lysogenic S. Typhimurium increased with decreasing pH value and increasing bile salt concentration. The Lysogenic S. Typhimurium cells were least susceptible to SGJ-4 and SGJ-5, showing <1 log reduction. The highest prophage induction was observed by 3.34 log PFU/ml in Lysogenic S. Typhimurium at SGJ-3 in the presence of 0.5 % bile salts. The numbers of invading Lysogenic S. Typhimurium treated at SGJ-3, SGJ-4, and SGJ-5 were 3.57, 3.73, and 4.15 log CFU/cm2, respectively. Most genes (hilA, hilC, hilD, invA, invE, invF, and sirA) were down-regulated in Lysogenic S. Typhimurium treated at SGJ-3, SGJ-4, and SGJ-5. This study provides useful information for understanding physiological changes of Lysogenic S. Typhimurium in the simulated gastrointestinal conditions.
-
Survival, prophage induction, and invasive properties of Lysogenic Salmonella Typhimurium exposed to simulated gastrointestinal conditions.
Archives of Microbiology, 2014Co-Authors: Songrae Kim, Kanghee Ryu, Debabrata Biswas, Juhee AhnAbstract:This study was designed to evaluate the viability, prophage induction, invasive ability, and relative gene expression in Lysogenic Salmonella Typhimurium exposed to the simulated gastric juice (SGJ) at pH 2 (SGJ-2), 3 (SGJ-3), 4 (SGJ-4), and 5 (SGJ-5) for 30 min followed by 0.5 % bile salts for 2 h. The susceptibility of Lysogenic S. Typhimurium increased with decreasing pH value and increasing bile salt concentration. The Lysogenic S. Typhimurium cells were least susceptible to SGJ-4 and SGJ-5, showing
José Luis García - One of the best experts on this subject based on the ideXlab platform.
-
molecular and biochemical analysis of the system regulating the lytic Lysogenic cycle in the pneumococcal temperate phage mm1
Fems Microbiology Letters, 2003Co-Authors: Virginia Obregón, Pedro García, Rubens López, José Luis GarcíaAbstract:The temperate phage MM1 forms stable lysogens in Streptococcus pneumoniae. We report here the first characterization of the Lysogenic control region in Pneumococcus which contains two functional divergent promoters (PR and PL). MM1 encodes a 14-kDa cI protein (CI) that appears to be responsible for maintaining the Lysogenic state in Pneumococcus since it prevents elongation of the transcripts controlled by PR and PL.
-
Molecular and biochemical analysis of the system regulating the lytic/Lysogenic cycle in the pneumococcal temperate phage MM1.
FEMS Microbiology Letters, 2003Co-Authors: Virginia Obregón, Pedro García, Rubens López, José Luis GarcíaAbstract:The temperate phage MM1 forms stable lysogens in Streptococcus pneumoniae. We report here the first characterization of the Lysogenic control region in Pneumococcus which contains two functional divergent promoters (PR and PL). MM1 encodes a 14-kDa cI protein (CI) that appears to be responsible for maintaining the Lysogenic state in Pneumococcus since it prevents elongation of the transcripts controlled by PR and PL.
John H Paul - One of the best experts on this subject based on the ideXlab platform.
-
Significance of Lysogeny in the Marine Environment: Studies with Isolates and a Model of Lysogenic Phage Production
Microbial Ecology, 1998Co-Authors: Sunny C Jiang, John H PaulAbstract:The importance of lysogeny in marine microbial populations is just beginning to be understood. To determine the abundance of lysogens in bacterial populations, we studied the occurrence of Lysogenic bacteria among bacterial isolates from a variety of marine environments. More than 116 bacteria isolated on artificial seawater nutrient agar plates were tested for the presence of inducible prophage by mitomycin C and UV radiation. Induction was determined as a decrease in culture absorbance at 600 nm, after treatment with inducing agents. Samples in which optical density decreased or remained the same after induction were further examined by transmission electron microscopy, for the presence of virus-like particles. More than 40% of the bacterial isolates contained inducible prophage, as determined by mitomycin C induction. A higher percentage of Lysogenic bacteria was found in isolates from oligotrophic environments, compared to coastal or estuarine environments. These studies suggest that Lysogenic bacteria are important components in marine microbial populations. However, a mathematical model based on viral and bacterial abundance and production rates suggests that, under normal conditions, Lysogenic viral production contributes less than 0.02% of total viral production. Therefore, lysogens in the marine environment may serve as a source of viruses and only contribute significantly to viral production during natural induction events.
-
occurrence of Lysogenic bacteria in marine microbial communities as determined by prophage induction
Marine Ecology Progress Series, 1996Co-Authors: Sunny C Jiang, John H PaulAbstract:Viruses are abundant and dynamic members of the marine microbial community, and it is important to understand the11 role in the ecology of natural microbial populations We have previously found Lysogenic bacteria to be a significant proportion (43%) of the cultivable heterotrophic microbial population. As the majority of marine bacteria are not cultivable using standard plating methods, we measured the proportion of marine Lysogenic bacteria in natural communities by prophage ~nduction. Mitomycin C, UV radiation, sunlight, temperature and pressure were used to induce prophage in lysogenlc bacteria from estuarine, coastal and oligotrophic offshore environments. To determine ~f hydrocarbon pollutants may cause the induction of marine lysogens, aromatic and aliphatic hydrocarbons (including Bunker C #6 fuel oil, phenanthrene, naphthalene, pyrene, and trichloroethylene) were also used as inducing agents. Induct~on was most often found in estuarine environments, where viral direct counts increased from 128.8 to 345% of the uninduced control, resulting in mortality of 10.5 to 67.3% (average 34%) of the bacterial population. Up to 38% of the bacterial population was lysogenized in estuanne environments, as calculated from an average burst size. Microbial populations from oligotrophic offshore environments were inducible at 3 of 11 stations sampled. Eight of the 11 samples (73 %) treated with polyaromatic hydrocarbons resulted in prophage induction in natural populations. Time series analysis was also conducted in 2 samples induced by mitomycin C from the Atlantic Ocean near the coast of North Carolina, USA. For both samples, significant decreases in bacterial numbers were detected in treated samples after 8 h of incubation. A significant increase of viruses was detected a t 8 h at one station and at 24 h at the other station after induction. This study indicates that natural Lysogenic populations are sensitive to a variety of ~nduc ing agents, and induction occurs more frequently in coastal and estuanne environments than offshore environments.
Songrae Kim - One of the best experts on this subject based on the ideXlab platform.
-
survival prophage induction and invasive properties of Lysogenic salmonella typhimurium exposed to simulated gastrointestinal conditions
Archives of Microbiology, 2014Co-Authors: Songrae Kim, Kanghee Ryu, Debabrata Biswas, Juhee AhnAbstract:This study was designed to evaluate the viability, prophage induction, invasive ability, and relative gene expression in Lysogenic Salmonella Typhimurium exposed to the simulated gastric juice (SGJ) at pH 2 (SGJ-2), 3 (SGJ-3), 4 (SGJ-4), and 5 (SGJ-5) for 30 min followed by 0.5 % bile salts for 2 h. The susceptibility of Lysogenic S. Typhimurium increased with decreasing pH value and increasing bile salt concentration. The Lysogenic S. Typhimurium cells were least susceptible to SGJ-4 and SGJ-5, showing <1 log reduction. The highest prophage induction was observed by 3.34 log PFU/ml in Lysogenic S. Typhimurium at SGJ-3 in the presence of 0.5 % bile salts. The numbers of invading Lysogenic S. Typhimurium treated at SGJ-3, SGJ-4, and SGJ-5 were 3.57, 3.73, and 4.15 log CFU/cm2, respectively. Most genes (hilA, hilC, hilD, invA, invE, invF, and sirA) were down-regulated in Lysogenic S. Typhimurium treated at SGJ-3, SGJ-4, and SGJ-5. This study provides useful information for understanding physiological changes of Lysogenic S. Typhimurium in the simulated gastrointestinal conditions.
-
Survival, prophage induction, and invasive properties of Lysogenic Salmonella Typhimurium exposed to simulated gastrointestinal conditions.
Archives of Microbiology, 2014Co-Authors: Songrae Kim, Kanghee Ryu, Debabrata Biswas, Juhee AhnAbstract:This study was designed to evaluate the viability, prophage induction, invasive ability, and relative gene expression in Lysogenic Salmonella Typhimurium exposed to the simulated gastric juice (SGJ) at pH 2 (SGJ-2), 3 (SGJ-3), 4 (SGJ-4), and 5 (SGJ-5) for 30 min followed by 0.5 % bile salts for 2 h. The susceptibility of Lysogenic S. Typhimurium increased with decreasing pH value and increasing bile salt concentration. The Lysogenic S. Typhimurium cells were least susceptible to SGJ-4 and SGJ-5, showing
Virginia Obregón - One of the best experts on this subject based on the ideXlab platform.
-
molecular and biochemical analysis of the system regulating the lytic Lysogenic cycle in the pneumococcal temperate phage mm1
Fems Microbiology Letters, 2003Co-Authors: Virginia Obregón, Pedro García, Rubens López, José Luis GarcíaAbstract:The temperate phage MM1 forms stable lysogens in Streptococcus pneumoniae. We report here the first characterization of the Lysogenic control region in Pneumococcus which contains two functional divergent promoters (PR and PL). MM1 encodes a 14-kDa cI protein (CI) that appears to be responsible for maintaining the Lysogenic state in Pneumococcus since it prevents elongation of the transcripts controlled by PR and PL.
-
Molecular and biochemical analysis of the system regulating the lytic/Lysogenic cycle in the pneumococcal temperate phage MM1.
FEMS Microbiology Letters, 2003Co-Authors: Virginia Obregón, Pedro García, Rubens López, José Luis GarcíaAbstract:The temperate phage MM1 forms stable lysogens in Streptococcus pneumoniae. We report here the first characterization of the Lysogenic control region in Pneumococcus which contains two functional divergent promoters (PR and PL). MM1 encodes a 14-kDa cI protein (CI) that appears to be responsible for maintaining the Lysogenic state in Pneumococcus since it prevents elongation of the transcripts controlled by PR and PL.
