scholarly journals Some relationships between R-factor and chromosomal β-lactamase in Gram-negative bacteria

1971 ◽  
Vol 123 (4) ◽  
pp. 507-512 ◽  
Author(s):  
J. W. Dale ◽  
J. T. Smith

1. The β-lactamases specified by Klebsiella aerogenes 418 and the R-factor R-7268 have been partially purified. 2. The molecular weights of the K. aerogenes strains 418 and 373, Aerobacter cloacae 53, R-7268 and R-TEM β-lactamases were all about 20000; that of the enzymes from Escherichia coli strains 419 and 214T was about 31000. 3. These enzymes were also compared by means of their Km values for benzylpenicillin and ampicillin, and their behaviour on starch-gel electrophoresis. 4. The β-lactamases specified by the two Klebsiella strains, the Aerobacter strain, and the R-factors R-TEM and R-7268 were found to comprise a broadly similar group. However, within this group, only two enzymes seemed to be identical, namely those specified by the two R-factors. The two E. coli strains produce identical β-lactamases which are very different from the ‘Klebsiella/Aerobacter-type’ enzymes.

1971 ◽  
Vol 123 (4) ◽  
pp. 501-505 ◽  
Author(s):  
J. W. Dale

1. The amino acid composition of the β-lactamase from E. coli (R-1818) was determined. 2. The R-1818 β-lactamase is inhibited by formaldehyde, hydroxylamine, sodium azide, iodoacetamide, iodine and sodium chloride. 3. The Km values for benzylpenicillin, ampicillin and oxacillin have been determined by using the R-factor enzyme from different host species. The same values were obtained, irrespective of the host bacterium. 4. The molecular weight of the enzyme was found to be 44600, and was the same for all host species. 5. The relationship of R-1818 and R-GN238 β-lactamases is discussed.


1966 ◽  
Vol 44 (4) ◽  
pp. 487-495 ◽  
Author(s):  
John Y. S. Chan ◽  
Edwin T. Mertz

Activated, purified bovine plasminogen, when fractionated on a Sephadex column, revealed four major protein peaks. Bovine plasmin I and plasmin II were found under peak II and peak III, respectively. Highly potent bovine plasmin II was recovered from peak III. Activated human plasminogen, when fractionated by the same technique, yielded an elution curve similar to that of the nonactivated sample. The pathway of the breakdown of bovine plasminogen upon activation with urokinase was studied by starch-gel electrophoresis and Sephadex chromatography. It is suggested that native bovine plasminogen is first converted to an altered plasminogen, which is then converted to plasmin I, plasmin I is then converted to plasmin II, and plasmin II to peptide A. The molecular weights of plasmin I, plasmin II, and peptide A were estimated by the Sephadex method to be 8.0 × 104, 6.2 × 104, and 4.3 × 104, respectively.


1965 ◽  
Vol 32 (2) ◽  
pp. 181-186 ◽  
Author(s):  
H. A. Veringa ◽  
M. F. Kerkhof Mogot

SummaryWhole casein, β-casein, β-lactoglobulin and euglobulin were labelled with 131I. The conditions under which iodination was carried out were chosen so as to avoid any modification of the original characteristics of the proteins. This was checked by starch-gel electrophoresis and determination of sedimentation constants, apparent molecular weights and, for euglobulin, the clustering effect on fat globules.As was shown by autoradiograms of the starch-gel plates, the radioactivity was incorporated in all zones of the electrophoresis pattern.


1966 ◽  
Vol 101 (3) ◽  
pp. 665-673 ◽  
Author(s):  
JL Leaver ◽  
HJ Cruft

1. Methods have been developed for the extraction and purification of bacterial basic proteins. These proteins were initially examined by a micro-method of starch-gel electrophoresis and were then characterized more fully. 2. Although it was found that most of the DNA in both Bacillus megaterium and Escherichia coli must be free from combination with basic protein, there was some evidence that a small portion might be in the form of a typical nucleohistone complex. 3. The ribosomes of both B. megaterium and E. coli were shown to contain approximately 2% of basic protein. On the basis of ultraviolet-absorption curves, partial amino acid analyses and their behaviour on electrophoresis in polyacrylamide gels, it was concluded that some of these ribosomal basic proteins may be extremely similar to typical histones. 4. These results are discussed in relation to those of other authors, and the possible functions of basic proteins present in micro-organisms are considered with reference to those that have already been proposed for the histones of higher organisms.


1969 ◽  
Vol 24 (6) ◽  
pp. 732-740 ◽  
Author(s):  
Milan Marek

Gel filtration on Sephadex G-200 was carried out on haemolymph proteins of prepupae. ligatured prepupae, male and female pupae and cooled pupae of Galleria mellonella L.The proteins were separated into two main fractions. The esterase activity of the eluated haemolymph was determined by means of beta-naphthyl acetate after filtration.After elution the samples were condensed and additionally separated on horizontal starch-gel electrophoresis.The “cooling protein” of pupae and the “ligature protein” of ligatured larvae of Galleria mellonella were shown by means of starch-gel electrophoresis to be new proteins, so far not described.The isoelectric point and molecular weight were determined for the individual protein fractions.They were then stained with amido black 10 B for the proof of proteins, and with alpha-naphthyl butyrate with Fast-Blue BB salt for the identification of esterases.


1996 ◽  
Vol 43 (2) ◽  
pp. 379-382 ◽  
Author(s):  
B Krawczyk ◽  
J Kur

We describe a fast and very efficient method of purification which yields highly purified integration host factor-like proteins in one chromatographic step. IHF-like proteins from Acinetobacter junii or Proteus vulgaris are each an alpha beta heterodimer (subunits of 10 and 11 kDa) similar to the IHF of Escherichia coli when analyzed by polyacrylamide gel electrophoresis. The purified IHF are able to bind to the same ihf sites as IHF of E. coli. The results presented confirm that IHF is conserved during evolution in gram-negative bacteria.


1961 ◽  
Vol 113 (5) ◽  
pp. 861-884 ◽  
Author(s):  
G. M. Edelman ◽  
M. D. Poulik

When human and rabbit 7S γ-globulins were reduced in strong urea solutions by a number of procedures, their molecular weights fell to approximately ⅓ of the original values. Partial separation of the reduction products was achieved using chromatography and starch gel electrophoresis in urea solutions. One of the components of reduced human 7S γ-globulin was isolated by chromatography, identified by starch gel electrophoresis, and subjected to amino acid analyses. The amino acid composition of this component differed from that of the starting material and also from that of the remaining components. A reduced pathological macroglobulin dissociated to components with an average molecular weight of 41,000. Several reduced human myeloma proteins, when subjected to starch gel electrophoresis, yielded individual patterns that nevertheless had features in common with those of reduced normal γ-globulins. Reduction of normal and abnormal γ-globulins was accompanied by the appearance of titratable sulfhydryl groups. Chemical treatments other than reduction were used to determine the type of bond holding the subunits together. It was tentatively concluded that they were linked by disulfide bonds. An hypothesis is presented to relate the structural features of the various γ-globulins in terms of the multiplicity of polypeptide chains in these molecules.


1964 ◽  
Vol 12 (01) ◽  
pp. 126-136 ◽  
Author(s):  
Karl H. Slotta ◽  
J. D Gonzalez

SummaryWhen urea or ε-amino caproic acid were used as solublizing agents for plasminogen in electrophoretic experiments, only one broad band of the proenzyme was obtained on acetate cellulose, in starch block, and in acrylamide gel. In starch gel electrophoresis, however, both forms of plasminogen – the native or euglobulin and Kline’s or Pseudoglobulin plasminogen – separated into six bands. These migrated toward the cathode at room temperature in borate or veronal buffer in the alkaline range and showed full activity in fibrinagar-streptokinase plates.


2019 ◽  
Vol 10 ◽  
pp. 1864-1872
Author(s):  
Prof. Teodora P. Popova

The effect of ionized aqueous solutions (anolytes and catholyte) in the processing of fruits (cherries, morellos, and strawberries) for decontamination has been tested. Freshly prepared analytes and catholyte without the addition of salts were used, as well as stored for 7 months anolytes, prepared with 0.5% NaCl and a combination of 0.5% NaCl and 0.5% Na2CO3. The anolyte prepared with a combination of 0.5% NaCl and 0.5% Na2CO3, as well as the anolyte obtained with 0.5% NaCl, exhibit high antimicrobial activity against the surface microflora of strawberries, cherries, and sour cherries. They inactivate E. coli for 15 minutes. The other species of the fam. Enterobacteriaceae were also affected to the maximum extent, as is the total number of microorganisms, especially in cherries and sour cherries. Even stored for 7 months, they largely retain their antimicrobial properties. Anolyte and catholyte, obtained without the addition of salts, showed a lower effect on the total number of microorganisms, but had a significant effect on Gram-negative bacteria, and especially with regard to the sanitary indicative E. coli.


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