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The relevance of this study is conditioned by the lack of detailed information on the structure and topography of the digestive organs of the Yemeni chameleon (Chamaeleo calyptratus). The purpose of this study was to find out the specific features of changes in body weight, topography, and structure of the digestive organs of the Yemeni chameleon, to determine their morphometric parameters in animals from 1 day to 1 year of age. The research material included the tongue, oesophagus, stomach, intestines, liver, and pancreas of chameleons of different sexes of 9 age groups. The data obtained were processed by one-factor analysis of variance (ANOVA). According to the topography, macroscopic structure and surface of the mucous membrane, there are three intestines in the small intestine: duodenum, jejunum, and ileum, and two intestines in the large intestine: the colon with a diverticulum and the rectum, which passes into the cloaca. A feature of the serous membrane of the chameleon intestine is that it is coloured black by melanin. From 1 day to 1 year of age, the body weight of chameleons increased 185.9 times, the snout-vent length (SVL) increased 6.7 times, the length of the digestive tract increased 3.8 times, and the ratio of the length of the digestive tract to SVL decreased from 3.2 to 1.8 times. The most intensive increase in body weight and SVL occurred during the second and third months of life. The relative length of the small intestine in chameleons of different age groups was 65.1-81.6%, with the longest part being the jejunum. The increase in the morphometric parameters of the stomach, intestines, liver, and pancreas was asynchronous. The most pronounced changes in their relative weight were determined in animals of 2-3 months of age. The obtained materials supplement and clarify the information on the topography and structure of the digestive organs of the Yemeni chameleon, and therefore they will be useful in X-ray and ultrasound examination during veterinary manipulations. [ABSTRACT FROM AUTHOR]

The antibacterial activities of the series of novel N'-(alpha-aminoacyl)- and N'-alpha-(N-akylamino)acyl derivatives of eremomycin and vancomycin containing hydrophobic moieties have been investigated. The N'-(N-alkylglycyl) derivatives of vancomycin are more active against vancomycin-susceptible staphylococci and enterococci and glycopeptide intermediate-resistant Staphylococcus aureus (GISA) than the corresponding eremomycin derivatives, but except for N'-[N-(p-octyloxybenzyl)glycyl-vancomycin] (28) and N'-[N-(p-octyloxybenzyl)-L-alanyl-vancomycin (33)--they are less active against glycopeptide-resistant enterococci (GRE). Derivatives 28 and 33 are the most active compounds (MIC's for glycopeptide-sensitive staphylococci and enterococci are 0.25 approximately 1 microg/ml, for GISA 1 approximately 2 microg/ml, for GRE 2 approximately 6 microg/ml). In in vivo studies, derivative 28 was active against S. aureus infections in mice with ED(50) 1 mg/kg versus 2 mg/kg for vancomycin (iv). In general N'-(N-alkylglycyl)-derivatives of vancomycin and eremomycin were more active than the corresponding N'-aminoacylated derivatives of these antibiotics containing other than glycin amino acids (L-Lys, L-Met, L-Orn, L- and D-Ala) and also L- and D-Phe or benzyl-O-L-Tyr.

The acylation of unprotected vancomycin or eremomycin with activated esters of N(alpha)-protected amino acids or N(alpha)-alkyl-N(alpha)-Fmoc-amino acids is directed selectively to the amino group of the disaccharide branch (N') and after Fmoc-group removal leads to the corresponding N'-alpha-aminoacyl derivatives. A series of N'-alpha-aminoacyl and N'-alpha-(N(alpha)-alkylamino)acyl derivatives of eremomycin and vancomycin containing hydrophobic moieties has been synthesized. The structures of all derivatives were confirmed by Electrospray Ionization mass-spectral (ESI MS) analysis, and by chemical degradation methods. Position of the introduced N'-alpha-aminoacyl- and N-(N(alpha)-alkylamino)acyl groups were determined after Edman degradation and acidic hydrolysis. The structures of the synthesized starting reagents (N(alpha)-alkylamino acids or N(alpha)-alkyl-N(alpha)-Fmocamino acids) were confirmed by NMR-spectra data. In general, N'-(N-alkylglycyl)-derivatives were more active than the corresponding N'-alpha-(N(alpha)-alkylamino)acylated derivatives containing other amino acids (L-Lys, L-Met, L-Orn, L- and D-Ala, L- and D-Phe and benzyl-O-L-Tyr).