Antimicrobial targets should be essential to the life or pathogenicity of bacteria and contain co... more Antimicrobial targets should be essential to the life or pathogenicity of bacteria and contain conserved target binding regions. This chapter reviews the antimicrobial target sites, their structures, roles, and their inhibition. Life-essential targets include FtsZ and their regulatory proteins; they mediate the cell division and its accompanying modifications in the cell wall. Peptidoglycan biosynthesis enzymes also belong to life-essential targets; we focused on the integral membrane protein MraY, the membrane-associated protein MurG, and penicillin-binding proteins (PBPs) rather than Mur enzymes due to their in vivo inaccessibility. Targeting DNA, as an essential element, may damage the strands or interfere with the replication mechanisms, or even specific genes; sequence-specific binders are designed. For expanding the drug targets, bacterial quorum sensing systems (QSs) are targeted; it regulates several genes; we reviewed the quorum quenching through several approaches. Other targets would provide new anti-virulence drugs. The d-alanylation of teichoic acid represents a potential target in Gram-positive bacteria; we discussed the specificity and inter-species conservation of the key enzyme (d-Alanyl carrier protein ligase) in this pathway.
Polish journal of microbiology / Polskie Towarzystwo Mikrobiologów = The Polish Society of Microbiologists, 2011
Optimizing production of alpha-amylase production by Thermoactinomyces vulgaris isolated from Egy... more Optimizing production of alpha-amylase production by Thermoactinomyces vulgaris isolated from Egyptian soil was studied. The optimum incubation period, temperature and initial pH of medium for organism growth and enzyme yield were around 24 h, 55 degrees C and 7.0, respectively. Maximum alpha-amylase activity was observed in a medium containing starch as carbon source. The other tested carbohydrates (cellulose, glucose, galactose, xylose, arabinose, lactose and maltose) inhibited the enzyme production. Adding tryptone as a nitrogen source exhibited a maximum activity of alpha-amylase. Bactopeptone and yeast extract gave also high activity comparing to the other nitrogen sources (NH4CI, NH4NO3, NaNO3, KNO3, CH3CO2NH4). Electrophoresis profile of the produced two alpha-amylase isozymes indicated that the same pattern at about 135-145 kDa under different conditions. The optimum pH and temperature of the enzyme activity were 8.0 and 60 degrees C, respectively and enzyme was stable at 50...
Optimizing production of alpha-amylase production by Thermoactinomyces vulgaris isolated from Egy... more Optimizing production of alpha-amylase production by Thermoactinomyces vulgaris isolated from Egyptian soil was studied. The optimum incubation period, temperature and initial pH of medium for organism growth and enzyme yield were around 24 h, 55 degrees C and 7.0, respectively. Maximum alpha-amylase activity was observed in a medium containing starch as carbon source. The other tested carbohydrates (cellulose, glucose, galactose, xylose, arabinose, lactose and maltose) inhibited the enzyme production. Adding tryptone as a nitrogen source exhibited a maximum activity of alpha-amylase. Bactopeptone and yeast extract gave also high activity comparing to the other nitrogen sources (NH4CI, NH4NO3, NaNO3, KNO3, CH3CO2NH4). Electrophoresis profile of the produced two alpha-amylase isozymes indicated that the same pattern at about 135-145 kDa under different conditions. The optimum pH and temperature of the enzyme activity were 8.0 and 60 degrees C, respectively and enzyme was stable at 50...
AN ISOLATE of Streptomyces was phenotypically, morphologically and physiologically characterized ... more AN ISOLATE of Streptomyces was phenotypically, morphologically and physiologically characterized and identified as Streptomyces violaceoruber ES. Its identification was confirmed using 16S rRNA gene sequencing. It produced a metabolite containing deep pink pigment that might be involved in silver nanoparticles (AgNPs) biosynthesis. Both crude metabolite on starch nitrate medium and partially purified metabolite with ammonium sulphate precipitation were tested for AgNPs synthesis. The biosynthesis protocol had environmental advantages of green synthesis and superior nanoparticles properties included regular rounded shape, size range from 13 nm to 27 nm, and bactericidal efficiency. The AgNPs synthesis was performed within one minute at room temperature and sun light. This guarantees high biosafety, low cost, less consumption of energy, rapid and simplicity of its biosynthesis. Furthermore, the synthesized AgNPs showed antibacterial activity against multidrug resistant strains of E. c...
Streptomyces griseorubens xylanase was immobilized on various carriers by different methods of im... more Streptomyces griseorubens xylanase was immobilized on various carriers by different methods of immobilization, including Sephadex G-50, chitosan and Ca alginate. In all cases, optimum pH of the immobilized xylanase were shifted to lower pH than those of free enzyme. The optimum reaction temperatures of immobilized xylanase on Sephadex G-50 and chitosan were shifted from 50-60 oC to 30 oC, whereas that of Ca alginate doesn't change. The half life time of immobilized xylanase on chitosan and Ca alginate was higher than those of native enzyme at 60 oC. The Km and Vmax values of immobilized xylanase were changed irregularly from those of native xylanase. A packed bead column type reactor of Ca alginate immobilized xylanase was prepared under optimum condition for continuous hydrolysis of xylan, rice straw and wheat straw. The operational stability of the reactor was evaluated successfully for five and half hours.
This book includes taxonomical, physiological, biochemical and molecular studies of amylolytic th... more This book includes taxonomical, physiological, biochemical and molecular studies of amylolytic thermophilic actinomycetes. A total of 36 actinomycetes were isolated from soil, mushroom compost and other compost samples. Four of the isolated thermophilic actinomycetes that exhibited the highest amylolytic activities were characterized and identified as: Thermoactinomyces sp, T. vulgaris and T. intermedius (two isolates). T. vulgaris, the best producer of α-amylase, was selected for further investigation. The optimum conditions for the production are: 24 hours incubation, 55ºC, pH 7.0, starch and tryptone as carbon and nitrogen sources, respectively. At different conditions of production, α-amylase electrophoresis profile had the same pattern of two isozyme with molecular weight between 135 and 145 kDa. Purification of this α-amylase was carried out by ammonium sulfate precipitation, dialysis, gel filtration and anion exchange chromatography. Physiochemical and molecular studies of th...
Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology], 2014
Two mesophilic streptomycetes (S. violaceoruber and S. spiroverticillatus) were selected to study... more Two mesophilic streptomycetes (S. violaceoruber and S. spiroverticillatus) were selected to study their Poly R-478 decolorization ability and lignocellulose solubilizing activity. Both strains were able to degrade Poly R-478 dye and ferulic acid during growth on a minimal salts medium. The Poly R-478 decolorizing activities of both strains were induced by adding different carbon sources to the culture media. S. violaceoruber could decolorize 63% of Poly R-478 after 24 h. Both strains could solubilize straw and produce acid-precipitable polymeric lignin (APPL) with different efficiency. From the major extracellular enzymes recovery of both strains on rice and wheat straw, we can predicate that the biodegradation process was partial indicating a possible utilization in biological delignification.
Antimicrobial targets should be essential to the life or pathogenicity of bacteria and contain co... more Antimicrobial targets should be essential to the life or pathogenicity of bacteria and contain conserved target binding regions. This chapter reviews the antimicrobial target sites, their structures, roles, and their inhibition. Life-essential targets include FtsZ and their regulatory proteins; they mediate the cell division and its accompanying modifications in the cell wall. Peptidoglycan biosynthesis enzymes also belong to life-essential targets; we focused on the integral membrane protein MraY, the membrane-associated protein MurG, and penicillin-binding proteins (PBPs) rather than Mur enzymes due to their in vivo inaccessibility. Targeting DNA, as an essential element, may damage the strands or interfere with the replication mechanisms, or even specific genes; sequence-specific binders are designed. For expanding the drug targets, bacterial quorum sensing systems (QSs) are targeted; it regulates several genes; we reviewed the quorum quenching through several approaches. Other targets would provide new anti-virulence drugs. The d-alanylation of teichoic acid represents a potential target in Gram-positive bacteria; we discussed the specificity and inter-species conservation of the key enzyme (d-Alanyl carrier protein ligase) in this pathway.
Polish journal of microbiology / Polskie Towarzystwo Mikrobiologów = The Polish Society of Microbiologists, 2011
Optimizing production of alpha-amylase production by Thermoactinomyces vulgaris isolated from Egy... more Optimizing production of alpha-amylase production by Thermoactinomyces vulgaris isolated from Egyptian soil was studied. The optimum incubation period, temperature and initial pH of medium for organism growth and enzyme yield were around 24 h, 55 degrees C and 7.0, respectively. Maximum alpha-amylase activity was observed in a medium containing starch as carbon source. The other tested carbohydrates (cellulose, glucose, galactose, xylose, arabinose, lactose and maltose) inhibited the enzyme production. Adding tryptone as a nitrogen source exhibited a maximum activity of alpha-amylase. Bactopeptone and yeast extract gave also high activity comparing to the other nitrogen sources (NH4CI, NH4NO3, NaNO3, KNO3, CH3CO2NH4). Electrophoresis profile of the produced two alpha-amylase isozymes indicated that the same pattern at about 135-145 kDa under different conditions. The optimum pH and temperature of the enzyme activity were 8.0 and 60 degrees C, respectively and enzyme was stable at 50...
Optimizing production of alpha-amylase production by Thermoactinomyces vulgaris isolated from Egy... more Optimizing production of alpha-amylase production by Thermoactinomyces vulgaris isolated from Egyptian soil was studied. The optimum incubation period, temperature and initial pH of medium for organism growth and enzyme yield were around 24 h, 55 degrees C and 7.0, respectively. Maximum alpha-amylase activity was observed in a medium containing starch as carbon source. The other tested carbohydrates (cellulose, glucose, galactose, xylose, arabinose, lactose and maltose) inhibited the enzyme production. Adding tryptone as a nitrogen source exhibited a maximum activity of alpha-amylase. Bactopeptone and yeast extract gave also high activity comparing to the other nitrogen sources (NH4CI, NH4NO3, NaNO3, KNO3, CH3CO2NH4). Electrophoresis profile of the produced two alpha-amylase isozymes indicated that the same pattern at about 135-145 kDa under different conditions. The optimum pH and temperature of the enzyme activity were 8.0 and 60 degrees C, respectively and enzyme was stable at 50...
AN ISOLATE of Streptomyces was phenotypically, morphologically and physiologically characterized ... more AN ISOLATE of Streptomyces was phenotypically, morphologically and physiologically characterized and identified as Streptomyces violaceoruber ES. Its identification was confirmed using 16S rRNA gene sequencing. It produced a metabolite containing deep pink pigment that might be involved in silver nanoparticles (AgNPs) biosynthesis. Both crude metabolite on starch nitrate medium and partially purified metabolite with ammonium sulphate precipitation were tested for AgNPs synthesis. The biosynthesis protocol had environmental advantages of green synthesis and superior nanoparticles properties included regular rounded shape, size range from 13 nm to 27 nm, and bactericidal efficiency. The AgNPs synthesis was performed within one minute at room temperature and sun light. This guarantees high biosafety, low cost, less consumption of energy, rapid and simplicity of its biosynthesis. Furthermore, the synthesized AgNPs showed antibacterial activity against multidrug resistant strains of E. c...
Streptomyces griseorubens xylanase was immobilized on various carriers by different methods of im... more Streptomyces griseorubens xylanase was immobilized on various carriers by different methods of immobilization, including Sephadex G-50, chitosan and Ca alginate. In all cases, optimum pH of the immobilized xylanase were shifted to lower pH than those of free enzyme. The optimum reaction temperatures of immobilized xylanase on Sephadex G-50 and chitosan were shifted from 50-60 oC to 30 oC, whereas that of Ca alginate doesn't change. The half life time of immobilized xylanase on chitosan and Ca alginate was higher than those of native enzyme at 60 oC. The Km and Vmax values of immobilized xylanase were changed irregularly from those of native xylanase. A packed bead column type reactor of Ca alginate immobilized xylanase was prepared under optimum condition for continuous hydrolysis of xylan, rice straw and wheat straw. The operational stability of the reactor was evaluated successfully for five and half hours.
This book includes taxonomical, physiological, biochemical and molecular studies of amylolytic th... more This book includes taxonomical, physiological, biochemical and molecular studies of amylolytic thermophilic actinomycetes. A total of 36 actinomycetes were isolated from soil, mushroom compost and other compost samples. Four of the isolated thermophilic actinomycetes that exhibited the highest amylolytic activities were characterized and identified as: Thermoactinomyces sp, T. vulgaris and T. intermedius (two isolates). T. vulgaris, the best producer of α-amylase, was selected for further investigation. The optimum conditions for the production are: 24 hours incubation, 55ºC, pH 7.0, starch and tryptone as carbon and nitrogen sources, respectively. At different conditions of production, α-amylase electrophoresis profile had the same pattern of two isozyme with molecular weight between 135 and 145 kDa. Purification of this α-amylase was carried out by ammonium sulfate precipitation, dialysis, gel filtration and anion exchange chromatography. Physiochemical and molecular studies of th...
Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology], 2014
Two mesophilic streptomycetes (S. violaceoruber and S. spiroverticillatus) were selected to study... more Two mesophilic streptomycetes (S. violaceoruber and S. spiroverticillatus) were selected to study their Poly R-478 decolorization ability and lignocellulose solubilizing activity. Both strains were able to degrade Poly R-478 dye and ferulic acid during growth on a minimal salts medium. The Poly R-478 decolorizing activities of both strains were induced by adding different carbon sources to the culture media. S. violaceoruber could decolorize 63% of Poly R-478 after 24 h. Both strains could solubilize straw and produce acid-precipitable polymeric lignin (APPL) with different efficiency. From the major extracellular enzymes recovery of both strains on rice and wheat straw, we can predicate that the biodegradation process was partial indicating a possible utilization in biological delignification.
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