Objective(s) Motility plays a major role in pathogenicity of Helicobacter pylori, yet there is  scarce data regarding its chemotactic behaviour. The present study was designed to investigate the chemotactic responses of local isolates of H. pylori towards various sugars, amino acids, as well as some other chemical substances. Materials and Methods Chemotaxis was assayed by a modified Adler’s...

Chirality plays a major role in recognition and interaction of biologically important molecules. The enzyme 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase (DAH7PS) is the first enzyme of the shikimate pathway, which is responsible for the synthesis of aromatic amino acids in bacteria and plants, and a potential target for the development of antibiotics and herbicides. DAH7PS from Mycobact...

A procedure for the precise determination of the D and L isomers in a given sample of an amino acid has been based upon chromatographic separation of the diastereoisomeric dipeptides obtained by derivatization with an L-amino acid N-carboxyanhydride. The conditions for the preparation of dipeptides developed by Hirschmann and associates make the derivatization step simple and rapid; the couplin...

From a strain of Bacillus subtilis a new antifungal peptidolipid complex of the iturin group was isolated. This antibiotic complex contained six lipophilic beta-amino acids with 3-amino-14-methylpentanoic acid as the predominant component. Iturin AL contains: 2 D-Asp, 1 L-Asp, 1 L-Glu, 1 L-Pro, 1 L-Ser, 1 D-Tyr and a mixture of 2.9% iso-C14-beta-amino acid, 30.7% n-C14-beta-amino acid, 15% iso-...

It has been shown that the 2’ endoautoaminoacylation of surface-bound RNA is stereoselective for the Lenantiomers of the amino acids (1). This mimics selection of amino acids by RNA in an early ‘RNA world’ (2), and thus may have led to the evolution of L-amino acid homochirality. However, the current selection of amino acids for protein synthesis utilizes the 3’ exoaminoacylated species exclusi...

background: dermatophagoides farinae and dermatophagoides pteronyssinus are house dust mites (hdm) that they cause severe asthma and allergic symptoms. tropomyosin protein plays an important role in mentioned immune and allergic reactions to hdms. here, tropomyosin protein from dermatophagoides spp. was comprehensively screened in silico for its allergenicity, antigenicity and similarity/conser...

There are significant differences in d-amino acid concentrations between healthy people and Alzheimer's disease patients. In order to investigate the potential correlation between d-amino acids and Alzheimer's disease, a simple and sensitive ultra high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method has been developed. The method was applied to simultaneous determ...

A series of mutations has been isolated that confer upon amino-acid auxotrophs of Escherichia coli K-12 the ability to grow when fed various D-amino acids. Several distinct systems, mediating cellular use of the D-isomers of leucine, histidine, phenylalanine, tyrosine, tryptophan, isoleucine, and valine, can be mutationally activated. Mutations leading to D-tryptophan use (dadR) all map near pu...