Three structurally related anticancer drugs, mithramycin, chromomycin A3, and olivomycin, exhibited large differences (greater than 100-fold) in their toxicity towards cultured cells from various species. These differences are species related, as all cell lines from any one species showed similar sensitivity to the three drugs. Of the three species examined, namely, human, mouse, and Chinese ha...

Two populations of Astyanax altiparanae (Garutti & Britski, 2000) of the Água dos Patos stream/SP and lake Igapó/PR were analyzed. All individuals showed 2n = 50, however, different karyotypic formulae were observed. The population of the Água dos Patos stream showed 8m +24sm+6st+12a (NF=88) and the population of lake Igapó, 8m+28sm+4st+10a (NF=90). Nucleolus organizing regions (AgNORs) were ob...

BACKGROUND Globozoospermia is a severe form of teratozoospermia (incidence < 0.1%) in infertile men that is characterized by round headed sperm and acrosomeless in semen. OBJECTIVE To compare the semen parameters, protamine deficiency, and apoptosis in ejaculated spermatozoa between globozoospermic and normozoospermic men. MATERIALS AND METHODS Thirty six semen samples were divided into two...

An experimental study was conducted between January 2002 and April 2003 for the detection of delayed hypersensitivity to Fonsecaea pedrosoi metabolic antigen (chromomycin) in skin tests. A total of 194 subjects were attended by spontaneous demand at the Infectious and Parasitic Diseases outpatient clinic of the Federal University of Maranhão-UFMA and at the Department of Microbiology, Federal U...

Cytogenetic studies were carried out on Rhamdella microcephala collected from the headwaters of the Machado river, a tributary of the Sapucaí river, Minas Gerais, Brazil. Sixteen specimens exhibited 2n556 chromosomes, with 18 metacentrics, 30 submetacentrics and 8 subtelocentric-acrocentrics (FN584). The nucleolar organizing regions (NORs) were identified in the interstitial position on the lon...

Anti-cancer antibiotics, chromomycin A3 (CHR) and mithramycin (MTR) inhibit DNA directed RNA synthesis in vivo by binding reversibly to template DNA in the minor groove with GC base specificity, in the presence of divalent cations like Mg2+. Under physiological conditions, (drug)2Mg2+ complexes formed by the antibiotics are the potential DNA binding ligands. Structures of CHR and MTR differ in ...

The biosynthesis of chromomycin A3 was investigated using 13C-labeled acetates, methionine and glucose, and 13C,18O-labeled acetate. 13C NMR spectral analysis demonstrated that: Aglycone assembly occurs by combining at least two polyketide chains; three of nine oxygen atoms of the aglycone originate from acetate precursor oxygen atoms; carbon methylations on the aromatic ring at C-7, on the chr...

Cytogenetic studies were carried out on eighteen wild specimens of Pterophyllum scalare from Jari River, in Pará state, and the results were compared to literature. Mitotic chromosomes were obtained from kidney cells and the analysis was done using: C-banding, Ag-NOR staining, Chromomycin A3/DAPI sequential staining and fluorochrome in situ hybridization with human telomere probes. All individu...