Escherichia coli K-12 WcaJ and the Caulobacter crescentus HfsE, PssY, and PssZ enzymes are predicted to initiate the synthesis of colanic acid (CA) capsule and holdfast polysaccharide, respectively. These proteins belong to a prokaryotic family of membrane enzymes that catalyze the formation of a phosphoanhydride bond joining a hexose-1-phosphate with undecaprenyl phosphate (Und-P). In this stu...

The uncoupler 2,4-dinitrophenol prevents in vivo synthesis of O antigen in Salmonella typhimurium by inhibiting the first reaction of the pathway, formation of galactosyl-pyrophosphoryl-undecaprenol. Inhibition was observed only in intact cells; dinitrophenol had no effect on activity of the synthase enzyme in isolated membrane fractions. In vivo inhibition could not be explained by changes in ...

The aim of the present study was to evaluate the effect of a hydro-alcoholic extract of Vitex agnus-castus (VAC) fruit on blood urea nitrogen (BUN), creatinine (Cr) and, kidney histology of a female mouse model of D-galactose induced aging. In this experimental study, 72 NMRI mice were divided into 6 groups: control, VAC, D-galactose, D-galactose+VAC, aging, and aging+VAC. D-galactose was injec...

Extraction of the cell envelope of E. coli with 1% sodium dodecyl sulfate yielded a lipopolysaccharide protein that was purified to homogeneity by conventional techniques. Analysis of the pure protein indicated that it is a complex lipopolysaccharide protein with the following molar ratios of constitutents: 3-deoxyoctulosonate, 1.0; glucosamine, 1.3; neutral sugar (glucose + heptose), 1.0; orga...

The ability of suspensions of BALB/c cells to catalyze the incorporation of nucleotide sugars into complex polysaccha rides has been compared. These cells have previously been characterized for concanavalin A-induced agglutinability, tumonigenicity, and malignancy. All of the cell lines tested catalyze transfer of the sugar moieties of cytosine 5'-mono phosphate N-acetylneuraminic acid, unidine...

Sansanmycins, produced by Streptomyces sp. strain SS, are uridyl peptide antibiotics with activities against Pseudomonas aeruginosa and multidrug-resistant Mycobacterium tuberculosis. In this work, the biosynthetic gene cluster of sansanmycins, comprised of 25 open reading frames (ORFs) showing considerable amino acid sequence identity to those of the pacidamycin and napsamycin gene cluster, wa...

A new positional isotope exchange method has been developed that can be used for the analysis of enzyme-catalyzed reactions which have ping-pong kinetic mechanisms. The technique can be used to measure the relative rates of ligand dissociation from enzyme-product complexes. Enzyme is incubated with the labeled substrate and an excess of the corresponding unlabeled product. The partitioning of t...

The electrophilic, free radical and reactive oxygen species scavenging and detoxification potentials of Lophiraalata stem bark was evaluated. L. alata stem bark effectively scavenged DPPH radical, superoxideion and hydrogen peroxide. It produced 88% scavenging effect of DPPH radical at a concentration of 1.0 mg/ml. Aqueous extract of L. alata-stem bark produced 76% and 92% scavenging effect on ...

d-galactose induces pancreatic disorder along with aging mouse model. vitex agnus-castus (vac) has potential pancreatic protective effect. hence, this study was designed to evaluate the hypoglycemic and pancreas protective effects of vac hydroalcoholic extract in d-galactose-induced aging female mice. in the present experimental study, 72 adult female naval medical research institute (nmri) mic...