Drugs online research references
Antibiot Khimioter. 1992 Dec;37(12):26-8.
[Selection of Penicillium chrysogenum--producer of penicillin with several valuable technologic features]
[Article in Russian]
Rusinov SF.
The efficiency of the routine methods for improvement of P. chrysogenum providing specific selection by several features with testing one of them was studied. A new highly potent strain of P. chrysogenum producing phenoxymethylpenicillin was isolated. The strain is characterized by a shorter fermentation cycle, lower viscosity of the fermentation broth and capacity for synthesizing 32,600 units/ml of phenoxymethylpenicillin under industrial conditions (in a lactose medium) by the 97th hour of the cultivation in fermenters with energy consumption of 1.3 kW. The increased amylolytic activity of the strain and the decreased viscosity of the fermentation broth provided using of the fermentation media containing 3.5 per cent of corn meal.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1304123&dopt=Abstract
Antibiot Khimioter. 1992 Jan;37(1):3-6.
[Effect of penicillin precursors on antibiotic biosynthesis in various strains]
[Article in Russian]
Tikhonova OV, Suvorova MV, Bartoshevich IuE, Lur'e LM.
The regularities of biosynthesis of 6-aminopenicillanic acid (6-APA), benzylpenicillin (BP) and phenoxymethylpenicillin (PMP) by the strains under the investigation did not significantly differ. In the absence of the precursor both the strains mainly synthesized 6-APA. Phenylacetic acid (PAA) and phenoxyacetic acid (POAA) provided directed biosynthesis: the fungus synthesized BP or PMP depending on the precursor nature. When the amount of the precursors was not sufficient, 6-APA was synthesized along with the penicillins. PAA proved to be a more active precursor than POAA. When both precursors were present in the fermentation broth, only BR was synthesized. An important distinction of strain 316A was its increased sensitivity to PAA especially in the initial period. After an increase in the PAA concentration the growth rate of strain 316A lowered to a greater extent than that of strain 284A. This was likely to determine the higher levels of penicillin production by strain 316A in the presence of POAA, a nontoxic precursor. A procedure for supplying the precursors was developed. Under the laboratory conditions it provided high levels of the penicillin production.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1326929&dopt=Abstract
Infect Immun. 1992 Oct;60(10):4024-31.
Modification in penicillin-binding proteins during in vivo development of genetic competence of Haemophilus influenzae is associated with a rapid change in the physiological state of cells.
Dargis M, Gourde P, Beauchamp D, Foiry B, Jacques M, Malouin F.
Departement de Microbiologie, Centre de Recherche du Centre Hospitalier de l'Universite, Ste-Foy, Quebec, Canada.
By using whole-cell labeling assay with 125I-penicillin V, we observed a reduction in the binding of the radiolabeled beta-lactam to four or five penicillin-binding proteins (PBPs) in Haemophilus influenzae cells cultivated under specific conditions. PBPs 3A, 3B, 4, and 6 were altered after the growth of bacteria in diffusion chambers implanted in the peritoneal cavity of rats. PBP 2 was also modified when cells were cultivated in human cerebrospinal fluids. Because this observation may have important consequences on the efficacy of beta-lactams during antibiotic therapy, we characterized the physiological state of bacteria cultivated in animals in the hope of explaining how such important changes in cell properties develop in vivo. Since the development of natural genetic competence occurs at the stationary phase of growth in H. influenzae, we used a DNA transformation assay to evaluate the physiological state of bacteria grown in diffusion chambers implanted in rats. Chromosomal DNA isolated from an antibiotic-resistant donor strain was mixed with bacteria in diffusion chambers. At different times during a 5-h incubation period, recipient bacteria were collected from the chambers, CFU were determined by plate counting, and antibiotic-resistant transformants were isolated on selective plates. Genetic competence rapidly developed in cells grown in rats, and the frequency of transformation by test DNA was elevated. Electron microscopy revealed an irregular cell shape and blebs at the surface of bacteria cultivated in animals and in cerebrospinal fluids. In an attempt to induce a similar physiological state in vitro, we supplemented broth cultures with cyclic AMP or synchronized cultures by a nutritional upshift. No changes in PBPs were observed with supplemental cyclic AMP or during a single cell cycle. Finally, a reduction in the affinity of PBPs for 125I-penicillin V identical to that observed in bacteria grown in rats was observed in cells isolated from the stationary phase of growth in vitro. These results clearly indicate that H. influenzae cells grown in animals undergo a rapid change to a physiological state similar to that found in late-stationary-phase cultures in vitro. This observation indicates that the rational design of future and improved antibiotic therapy of H. influenzae infections should consider cell properties of slow-growing or latent bacteria.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1328054&dopt=Abstract
Herbs and Pharmaceuticals Online ||
Hair Million herbal formula for hair loss and hair growth ||
Wellstreet online pharmacy for click-order prescription medications ||
Altace Online Pharmacy ||
Rx Drugs USA, Prescription Drugs Online Pharmacy ||
Insurance plans and information ||
Insurance policies for all purposes ||
Antibiotics and prescription medications online literature ||