scholarly journals Genetic and biochemical characterization of the chromosome-encoded class B β-lactamases from Shewanella livingstonensis (SLB-1) and Shewanella frigidimarina (SFB-1)

2005 ◽  
Vol 55 (5) ◽  
pp. 680-685 ◽  
Author(s):  
Laurent Poirel ◽  
Claire Héritier ◽  
Patrice Nordmann
Keyword(s):  
Biochemical Characterization ◽  
Shewanella Frigidimarina ◽  
Class B ◽  
Shewanella Livingstonensis

scholarly journals Genetic and Biochemical Characterization of CGB-1, an Ambler Class B Carbapenem-Hydrolyzing β-Lactamase from Chryseobacterium gleum

2002 ◽  
Vol 46 (9) ◽  
pp. 2791-2796 ◽  
Author(s):  
Samuel Bellais ◽  
Thierry Naas ◽  
Patrice Nordmann
Keyword(s):  
Reference Strain ◽  
Biochemical Characterization ◽  
Amino Acid Identity ◽  
Relative Molecular Mass ◽  
Class A ◽  
Molecular Subclass ◽  
Class B ◽  
Lactamase Gene ◽  
Chryseobacterium Gleum

ABSTRACT Chryseobacterium gleum (previously included in the Flavobacterium IIb species) is a gram-negative aerobe that is a source of nosocomial infections. An Ambler class B β-lactamase gene was cloned and expressed in Escherichia coli from reference strain C. gleum CIP 103039 that had reduced susceptibility to expanded-spectrum cephalosporins and carbapenems. The purified β-lactamase, CGB-1, with a pI value of 8.6 and a determined relative molecular mass of ca. 26 kDa, hydrolyzed penicillins; narrow- and expanded-spectrum cephalosporins; and carbapenems. CGB-1 was a novel member of the molecular subclass B1 of metallo-enzymes. It had 83 and 42% amino acid identity with IND-1 from Chryseobacterium indologenes and BlaB from C. meningosepticum, respectively. Thus, in addition to the previously characterized clavulanic acid-inhibited extended-spectrum β-lactamase CGA-1 of Ambler class A, C. gleum produces a very likely chromosome-borne class B β-lactamase.

scholarly journals Biochemical Characterization of Streptococcus pneumoniae Penicillin-Binding Protein 2b and Its Implication in β-Lactam Resistance

2004 ◽  
Vol 48 (5) ◽  
pp. 1848-1855 ◽  
Author(s):  
Estelle Pagliero ◽  
Laurent Chesnel ◽  
Julie Hopkins ◽  
Jacques Croizé ◽  
Otto Dideberg ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Biochemical Characterization ◽  
Protein A ◽  
Strain Analysis ◽  
Penicillin G ◽  
Penicillin Binding Protein ◽  
Class B ◽  
Selection Of

ABSTRACT Extensive use of β-lactam antibiotics has led to the selection of pathogenic streptococci resistant to β-lactams due to modifications of the penicillin-binding proteins (PBPs). PBP2b from Streptococcus pneumoniae is a monofunctional (class B) high-molecular-weight PBP catalyzing the transpeptidation between adjacent stem peptides of peptidoglycan. The transpeptidase domain of PBP2b isolated from seven clinical resistant (CR) strains contains 7 to 44 amino acid changes over the sequence of PBP2b from the R6 β-lactam-sensitive strain. We show that the extracellular soluble domains of recombinant PBP2b proteins (PBP2b*) originating from these CR strains have an in vitro affinity for penicillin G that is reduced by up to 99% from that of the R6 strain. The Thr446Ala mutation is always observed in CR strains and is close to the key conserved motif (S443SN). The Thr446Ala mutation in R6 PBP2b* displays a 60% reduction in penicillin G affinity in vitro compared to that for the wild-type protein. A recombinant R6 strain expressing the R6 PBP2b Thr446Ala mutation is twofold less sensitive to piperacillin than the parental S. pneumoniae strain. Analysis of the Thr446Ala mutation in the context of the PBP2b CR sequences revealed that its influence depends upon the presence of other unidentified mutations.

scholarly journals Biochemical characterization of the class B acid phosphatase (AphA) of Escherichia coli MG1655

2006 ◽  
Vol 1764 (1) ◽  
pp. 13-19 ◽  
Author(s):  
Claudio Passariello ◽  
Costantino Forleo ◽  
Vanna Micheli ◽  
Serena Schippa ◽  
Rosalida Leone ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Acid Phosphatase ◽  
Biochemical Characterization ◽  
Class B

Plant Pathology Diagnosed by X-Ray Microanalysis

1987 ◽  
Vol 45 ◽  
pp. 974-975
Author(s):  
J. H. Resau ◽  
N. Howell ◽  
S. H. Chang
Keyword(s):  
Electron Microscopy ◽  
Plant Pathology ◽  
Biochemical Characterization ◽  
Nutrient Deficiency ◽  
Green Leaf ◽  
Parasitic Infestation ◽  
X Ray

Spinach grown in Texas developed “yellow spotting” on the peripheral portions of the leaves. The exact cause of the discoloration could not be determined as there was no evidence of viral or parasitic infestation of the plants and biochemical characterization of the plants did not indicate any significant differences between the yellow and green leaf portions of the spinach. The present study was undertaken using electron microscopy (EM) to determine if a micro-nutrient deficiency was the cause for the discoloration.Green leaf spinach was collected from the field and sent by express mail to the EM laboratory. The yellow and equivalent green portions of the leaves were isolated and dried in a Denton evaporator at 10-5 Torr for 24 hrs. The leaf specimens were then examined using a JEOL 100 CX analytical microscope. TEM specimens were prepared according to the methods of Trump et al.

Interaction effect of rootstocks on gas exchange parameters, biochemical changes and nutrientstatus in Sauvignon Blanc winegrapes

2014 ◽  
Vol 3 (3) ◽  
pp. 218-225
Author(s):  
R. G. Somkuwar ◽  
M. A. Bhange ◽  
A. K. Upadhyay ◽  
S. D. Ramteke
Keyword(s):  
Biochemical Characterization ◽  
Reducing Sugar ◽  
Wine Grape ◽  
Gas Exchange Parameters ◽  
Food Material ◽  
Total Carbohydrates ◽  
Salt Creek ◽  
Grape Varieties ◽  
Photosynthetic Activities

SauvignonBlanc wine grape was characterized for their various morphological, physiological and biochemical parameters grafted on different rootstocks. Significant differences were recorded for all the parameters studied. The studies on vegetative parameters revealed that the rootstock influences the vegetative growth thereby increasing the photosynthetic activities of a vine. The highest photosynthesis rate was recorded in 140-Ru grafted vine followed by Fercal whereas the lowest in Salt Creek rootstock grafted vines.The rootstock influenced the changes in biochemical constituents in the grafted vine thereby helping the plant to store enough food material. Significant differences were recorded for total carbohydrates, proteins, total phenols and reducing sugar. The vines grafted on1103-Pshowed highest carbohydrates and starch followed by 140-Ru,while the least amount of carbohydrates were recorded in 110-R and Salt Creek grafted vines respectively.Among the different rootstock graft combinations, Fercal showed highest amount of reducing sugar, proteins and phenols, followed by 1103-P and SO4, however, the lowest amount of reducing sugar, proteins and phenols were recorded with 110-R grafted vines.The vines grafted on different rootstocks showed changes in nutrient uptake. Considering this, the physico-biochemical characterization of grafted vine may help to identify particularrootstocks combination that could influence a desired trait in commercial wine grape varieties after grafting.

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