Chemical modification of the lectin of the marine coral Gerardia savaglia by marine quinone avarone

The quinone avarone, isolated from the marine sponge Dysidea avara, possesses the ability to chemically modify proteins. In this work, modification of lectin isolated from the coral Gerardia savaglia by avarone was examined. The techniques used for studying the modification were: SDS PAGE, isoelectric focusing and hemagglutination testing. The results of the SDS PAGE indicate dimerization of the protein. A shift of the pI toward lower value occurs upon modification. The change of the hemagglutination activity of the protein confirms that chemical modification of G. savaglia lectin by avarone changes its ability to interact with the membrane of erythrocytes.Avaron, hinon izolovan iz morskog sunđera Dysidea avara, poseduje sposobnost da hemijski modifikuje proteine. U ovom radu ispitivana je modifikacija lektina izolovanog iz korala Gerardia savaglia avaronom. Tehnike za praćenje hemijske modifikacije bile su: SDS PAGE, izoelektrično fokusiranje i hemaglutinacioni test. Rezultati SDS PAGE upućuju na dimerizaciju proteina. Dolazi do pomeranja pI vrednosti proteina. Promena hemaglutinacione aktivnosti G. savaglia lektina avaronom uticala je na njegovu sposobnost interakcije sa membranom eritrocita

Synthesis and biological evaluation of 5-substituted derivatives of benzimidazole

A series of eight novel 5-substituted derivatives of benzimidazole was synthesized by condensation of the corresponding diamine with ethyl 4-[4-(2-chlorophenyl)piperazin-1-yl]butanoate in refluxing 4 M hydrochloric acid. In vitro antibacterial activity against ten strains, namely Bacillus subtilis, Clostridium sporogenes, Streptosporangium longisporum, Micrococcus flavus, Sarcina lutea, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Salmonella enteritidis and Proteus vulgaris and antifungal activity against two fungal strains, namely Candida albicans and Saccharomyces cerevisiae, were evaluated. Of all the compounds screened for activity, 2-{3-[4-(2-chlorophenyl)piperazin-1-yl]propyl}-5-iodo-1H-benzimidazole and 2-{3-[4-(2-chlorophenyl)piperazin-1-yl]propyl}-5-methyl-1H-benzimidazole were associated with higher antifungal activity than commercial drugs

Regioselectivity of conjugate additions to monoalkyl-1,4-benzoquinones

The regioselectivity of the reaction of conjugate addition of thiols, amines, methanol and hydrogen chloride with the monoalkyl-1,4-benzoquinones avarone and 2-tert-butyl-1,4-benzoquinone was investigated. It was shown that the regioselectivity of the reaction is influenced by the electrophilicity of position 5 in unprotonated 2-alkylquinones, the increased electrophilicity of position 6 in acidic medium, and by the acidity of the intermediate hydroquinones