Effects of vitamin B12 concentration on chemostat cultured Synechococcus sp. strain PCC 7002

1995 ◽  
Vol 41 (2) ◽  
pp. 145-151 ◽  
Author(s):  
Steven W. Wilhelm ◽  
Charles G. Trick
Keyword(s):  
Growth Rate ◽  
Vitamin B12 ◽  
Continuous Culture ◽  
Gel Electrophoresis ◽  
Outer Membrane Proteins ◽  
Polyacrylamide Gel Electrophoresis ◽  
Entire Group ◽  
Vitamin B ◽  
Limited Growth ◽  
Synechococcus Sp

The effects of vitamin B12 availability on the physiology of the cyanobacterium Synechococcus sp. strain PCC 7002 were examined in a continuous culture chemostat system. The availability of vitamin B12 within the system was demonstrated to control the cell density and cellular chlorophyll levels under nutrient-limiting conditions. Electron micrographs of vitamin B12 replete and vitamin B12 deficient cyanobacteria indicated that a reduction in vitamin B12 availability induced a loss of thylakoid integrity within the system. Polyacrylamide gel electrophoresis demonstrated that the expression of outer membrane proteins of 95, 70, and 34 kDa was enhanced during vitamin B12 limited growth. Cellular quotients were determined to be a minimum of 256 molecules of vitamin B12/cell to sustain a growth rate of 0.6/day. A comparison with eukaryotic plankton demonstrated that the vitamin B12 requirements of cyanobacteria may be more similar to those of chloroplasts than to those of the entire group of eukaryotic algae.Key words: chemostats, cellular quotients, cyanobacterial physiology, Synechococcus, vitamin B12.

Outer membrane proteins from Serratia marcescens

1993 ◽  
Vol 39 (1) ◽  
pp. 108-111 ◽  
Author(s):  
Marta Puig ◽  
Carme Fusté ◽  
Miquel Viñas
Keyword(s):  
Membrane Proteins ◽  
Serratia Marcescens ◽  
Outer Membrane ◽  
Nutrient Availability ◽  
Sodium Dodecyl Sulphate ◽  
Gel Electrophoresis ◽  
Outer Membrane Proteins ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Cultural Conditions

The outer membrane proteins (OMPs) of several strains of Serratia marcescens have been studied by sodium dodecyl sulphate – urea – polyacrylamide gel electrophoresis. Four major OMPs, named Omp1, Omp2, Omp3, and OmpA (42, 40, 39, and 37 kDa, respectively), have been visualized. The relative proportions of Omp2 and Omp3 depend on cultural conditions (temperature of incubation, osmolarity, and nutrient availability).Key words: Serratia marcescens, outer membrane proteins, porin.

Mechanisms of ertapenem resistance in Enterobacteriaceae isolates in a tertiary university hospital

2016 ◽  
Vol 64 (5) ◽  
pp. 1042-1049 ◽  
Author(s):  
Hae-Sun Chung ◽  
Dongeun Yong ◽  
Miae Lee
Keyword(s):  
Gel Electrophoresis ◽  
Molecular Mechanisms ◽  
Outer Membrane Proteins ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
University Hospital ◽  
Clinical Microbiology Laboratory ◽  
Sequencing Analysis ◽  
Sds Page ◽  
Broth Microdilution Method

The aim of this study was to investigate the molecular mechanisms of ertapenem resistance among Enterobacteriaceae isolates in a clinical microbiology laboratory at a tertiary university hospital. A total of 40 clinical isolates including 20 resistant and 20 intermediate isolates were collected from August 2012 to July 2013. Ertapenem susceptibility was confirmed by the broth microdilution method. PCR and sequencing analysis of carbapenemase, AmpC β-lactamase, and extended-spectrum β-lactamase (ESBL) genes were performed. Outer membrane proteins (OMPs) were examined by urea-sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Molecular epidemiology studies were performed by pulsed-field gel electrophoresis (PFGE). AmpC β-lactamases and ESBLs were found in 32 (80.0%) and 20 (50.0%) of the 40 isolates with ertapenem non-susceptibility, respectively. Distributions of β-lactamase genes differed among the species. OneCitrobacter freundiiisolate among the 40 isolates with ertapenem non-susceptibility carrying theblaIMP-1associated class 1 integron was detected. SDS-PAGE of OMPs showed altered or greatly diminished expression of porins in all isolates ofKlebsiella pneumoniae(n=5) andEnterobacter cloacae(n=11) with ertapenem resistance. Porin alterations were less common among the isolates with intermediate susceptibility (4/19). Integration of the results of molecular analysis of β-lactamases and OMP analysis revealed that most of the isolates with ertapenem resistance exhibited β-lactamase activity and porin alteration. PFGE revealed that most isolates were epidemiologically unrelated. Ertapenem resistance in clinical Enterobacteriaceae isolates was associated with β-lactamase activity and porin alteration. Even though carbapenemase-producing Enterobacteriaceae are still rare, continuous monitoring and infection control for carbapenem-resistant Enterobacteriaceae are necessary.

6.14 Serum Vitamin B12 Concentrations in Growing Cattle and Their Relationship with Growth Rate and Cobalt Bullet Therapy

1983 ◽  
Vol 7 ◽  
pp. 145-146
Author(s):  
D. I. Givens ◽  
V. R. Simpson
Keyword(s):  
Growth Rate ◽  
Vitamin B12 ◽  
Isotope Dilution ◽  
Serum Vitamin ◽  
Vitamin B ◽  
A Value ◽  
Growing Cattle

The interpretation of serum vitamin B12 concentrations in cattle is not well established but a value <350 ng/1 is commonly used to describe adequacy (MAFF, 1978). Three separate experiments explore this interpretation and the ability of cobalt (Co) bullets to increase serum vitamin B12 concentrations in cattle. In all cases, vitamin B12 has been measured microbiologically, using the organism L. leichmannii. In experiment 3, a number of samples were additionally analyzed using a radio isotope dilution (RID) technique.

scholarly journals Polynucleotide Phosphorylase from a Cyanobacterium (Synechococcus sp.): Subunit Composition and Properties

1982 ◽  
Vol 37 (7-8) ◽  
pp. 600-608 ◽  
Author(s):  
Wolf-Thomas Nolden ◽  
Gerhard Richter
Keyword(s):  
Molecular Mass ◽  
Isoelectric Focusing ◽  
Isoelectric Point ◽  
Gel Electrophoresis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Enzyme Molecule ◽  
Polynucleotide Phosphorylase ◽  
Synechococcus Sp ◽  
Single Polypeptide ◽  
Significant Stimulatory Effect

Abstract Polynucleotide phosphorylase from cells of the cyanobacterium Synechococcus sp. has been purified 1400-fold by an improved procedure. The enzyme purified to homogeneity and lacking nuclease, phosphatase and protease contaminations reveals a single band of ADP polymerizing activity upon polyacrylamide gel electrophoresis under nondenaturing conditions which cor­responds to a molecular mass of about 275 000. The enzyme migrates as a single polypeptide of Mr ≈ 70 000 when subjected to gel electrophoresis in the presence of dodecyl sulfate indicating a composition of α4 for the native enzyme molecule. The isoelectric point of the purified enzyme as determined by isoelectric focusing was found to be at 4.2 ± 0.1. Polynucleotide phosphorylase of Synechococcus is preferentially activated by Mg2+; KCl has a significant stimulatory effect.

Two-dimensional SDS–polyacrylamide gel electrophoresis of heat-modifiable outer-membrane proteins

1976 ◽  
Vol 22 (1) ◽  
pp. 83-91 ◽  
Author(s):  
R. R. B. Russell
Keyword(s):  
Gel Electrophoresis ◽  
Outer Membrane Proteins ◽  
Polyacrylamide Gel Electrophoresis ◽  
Polyacrylamide Gel ◽  
Two Dimensional ◽  
Two Temperatures ◽  
Cell Envelopes ◽  
Neisseria Sicca ◽  
Relationship Of ◽  
The Relationship

An examination has been made of the effect which temperature of solubilization has upon the subsequent migration in SDS–polyacrylamide gel electrophoresis of proteins from the cell envelopes of Escherichia coli K12 and Neisseria sicca ATCC 9913. Conventional electrophoresis in tubes revealed substantial differences in the staining patterns of gels, depending upon whether the envelope samples were solubilized at 37 °C or 100 °C; in the case of N. sicca at least 6 of 13 discernible bands displayed heat-modifiable behavior. The relationship of the bands produced by each of the two temperatures was investigated by a two-dimensional electrophoresis procedure, in which a sample was solubilized at 37 °C and run in a usual cylindrical gel; the entire gel was then resolubilized at 100 °C, and laid along an acrylamide slab for electrophoresis in the second dimension.It was found that "free endotoxin" of both organisms examined contained the same major proteins as the total envelope fraction, and that these free endotoxin proteins showed the same heat-modifiable properties as when present in total envelopes.

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