scholarly journals Plasmid-mediated trimethoprim-resistance in Staphylococcus aureus. Characterization of the first gram-positive plasmid dihydrofolate reductase (type S1)

1987 ◽  
Vol 243 (1) ◽  
pp. 309-312 ◽  
Author(s):  
H K Young ◽  
R A Skurray ◽  
S G B Amyes
Keyword(s):  
Staphylococcus Aureus ◽  
Dihydrofolate Reductase ◽  
Specific Activity ◽  
Gram Positive ◽  
Heat Stable ◽  
Dihydrofolate Reductases ◽  
High Degree ◽  
Moderately Resistant ◽  
Identification And Characterization

The trimethoprim-resistance gene located on plasmid pSK1, originally identified in a multi-resistant Staphylococcus aureus from Australia, encodes the production of a dihydrofolate reductase (type S1), which confers a high degree of resistance to its host and is quite unlike any plasmid-encoded dihydrofolate reductase hitherto described. It has a low Mr (19,700) and has a higher specific activity than the constitutive Gram-negative plasmid dihydrofolate reductases. The type S1 enzyme is heat-stable and has a relatively low affinity for the substrate, dihydrofolate (Km 10.8 microM). It is moderately resistant to trimethoprim, and is competitively inhibited by this drug with an inhibitor-binding constant of 11.6 microM. This is the first identification and characterization of a plasmid-encoded trimethoprim-resistant dihydrofolate reductase derived from a Gram-positive species.

scholarly journals Proteomic Characterization of Bacteriophage Peptides from the Mastitis Producer Staphylococcus aureus by LC-ESI-MS/MS and the Bacteriophage Phylogenomic Analysis

Foods ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 799
Author(s):  
Ana G. Abril ◽  
Mónica Carrera ◽  
Karola Böhme ◽  
Jorge Barros-Velázquez ◽  
Benito Cañas ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Dairy Products ◽  
Phylogenomic Analysis ◽  
Esi Ms ◽  
Complement Inhibitors ◽  
Staphylococcus Spp ◽  
The Relationship ◽  
Phage Proteins ◽  
Identification And Characterization

The present work describes LC-ESI-MS/MS MS (liquid chromatography-electrospray ionization-tandem mass spectrometry) analyses of tryptic digestion peptides from phages that infect mastitis-causing Staphylococcus aureus isolated from dairy products. A total of 1933 nonredundant peptides belonging to 1282 proteins were identified and analyzed. Among them, 79 staphylococcal peptides from phages were confirmed. These peptides belong to proteins such as phage repressors, structural phage proteins, uncharacterized phage proteins and complement inhibitors. Moreover, eighteen of the phage origin peptides found were specific to S. aureus strains. These diagnostic peptides could be useful for the identification and characterization of S. aureus strains that cause mastitis. Furthermore, a study of bacteriophage phylogeny and the relationship among the identified phage peptides and the bacteria they infect was also performed. The results show the specific peptides that are present in closely related phages and the existing links between bacteriophage phylogeny and the respective Staphylococcus spp. infected.

Identification and characterization of two novel superantigens among Staphylococcus aureus complex

2018 ◽  
Vol 308 (4) ◽  
pp. 438-446 ◽  
Author(s):  
Dao-Feng Zhang ◽  
Xin-Yi Yang ◽  
Jing Zhang ◽  
Xiaojie Qin ◽  
Xiaozhen Huang ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Identification And Characterization

scholarly journals Identification and characterization of UDP-N-acetylenolpyruvylglucosamine reductase (MurB) from the Gram-positive pathogen Streptococcus pneumoniae

2001 ◽  
Vol 355 (2) ◽  
pp. 431 ◽  
Author(s):  
Daniel R. SYLVESTER ◽  
Emilio ALVAREZ ◽  
Arun PATEL ◽  
Kapila RATNAM ◽  
Howard KALLENDER ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Gram Positive ◽  
Identification And Characterization

scholarly journals Purification and characterization of a heat-stable esterase from the thermoacidophilic archaebacterium Sulfolobus acidocaldarius

1988 ◽  
Vol 250 (2) ◽  
pp. 453-458 ◽  
Author(s):  
H Sobek ◽  
H Görisch
Keyword(s):  
Specific Activity ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sulfolobus Acidocaldarius ◽  
Sedimentation Equilibrium ◽  
Prolonged Storage ◽  
Heat Stable ◽  
Equilibrium Data ◽  
Poly Ethylene ◽  
Hydrolysis Of

A heat-stable esterase has been purified 1080-fold to electrophoretic homogeneity from Sulfolobus acidocaldarius, a thermoacidophilic archaebacterium; 20% of the starting activity is recovered. The purified enzyme shows a specific activity of 158 units/mg, based on the hydrolysis of p-nitrophenyl acetate. The esterase hydrolyses short-chain p-nitrophenyl esters, aliphatic esters and triacylglycerols. It is strongly inhibited by paraoxon and phenylmethanesulphonyl fluoride, but only weakly by eserine. From sedimentation-equilibrium data and molecular sieving in polyacrylamide gels, the Mr of the esterase is estimated to be 117000-128000. SDS/polyacrylamide-gel electrophoresis reveals a single band of protein, of Mr 32000. The purified esterase crystallizes in the presence of poly(ethylene glycol) in short rods. The enzyme is inactivated only on prolonged storage at temperature above 90 degrees C.

scholarly journals Characterization of Multiple forms of Human Thrombin

1977 ◽  
Author(s):  
J.J. Gorman ◽  
P.A. Castaldi
Keyword(s):  
Specific Activity ◽  
Peptide Mapping ◽  
Multiple Forms ◽  
Bovine Thrombin ◽  
Molecular Weights ◽  
Human Thrombin ◽  
Affinity Resin ◽  
C 50 ◽  
High Degree

Human thrombin was obtained by activation of partially purified human prothrombin with venom of the Australian Taipan (oxyuranus scutellatus scutellatus).The crude thrombin was precipitated with ammonium sulphate and subsequently purified by chromatography on Sephadex G-75 CM-Sephadex C-50 and the affinity resin am inobenzamidine-CH-Sepharose. The final preparation had a specific activity of 1700 units per absorbance unit (A| cm 280n m Was herterogenous as shown by urea-acrylamide gel electrophoresis at acid pH and by isoelectric focusing. SDS-acrylamide electrophoresis revealed molecular weights of 39,000, 28,000, 25-23,000 and 15-12,000 for these proteins. The 39,000 dalton species predominated (greater than 90%) when the enzyme was inhibited with phenyImethanesuI phony I fluoride prior to dialysis against 0.02M sod i urn phosphate (pH 8.0) containing 0.1% SDS. Lack of such inhibition reduced the amount of the 39,000 dalton species to less than 60% with concomitant increase in the smaller species. Increase in the smaller species also occurred during incubation in 0.IM NaCI-0.I M Tris buffer (pH 8.0).Peptide mapping studies indicated that the smaller species were structurally related to the 39,000 dalton species. Amino acid compositions of tryptic peptides indicated a high degree of homology with bovine thrombin.It has been established that human thrombin can exist in at least two secondary structural forms of different molecular weights, probably due to autolytic degradation of the largest (39,000 dalton) protein species.

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