Analysis of ten Brucella genomes reveals evidence for horizontal gene transfer despite a preferred intracellular lifestyle.

The facultative intracellular bacterial pathogen Brucella infects a wide range of warm-blooded land and marine vertebrates and causes brucellosis. Currently, there are nine recognized Brucella species based on host preferences and phenotypic differences. The availability of 10 different genomes consisting of two chromosomes and representing six of the species allowed for a detailed comparison among themselves and relatives in the order Rhizobiales. Phylogenomic analysis of ortholog families shows limited divergence but distinct radiations, producing four clades as follows: Brucella abortus-Brucella melitensis, Brucella suis-Brucella canis, Brucella ovis, and Brucella ceti. In addition, Brucella phylogeny does not appear to reflect the phylogeny of Brucella species' preferred hosts. About 4.6% of protein-coding genes seem to be pseudogenes, which is a relatively large fraction. Only B. suis 1330 appears to have an intact beta-ketoadipate pathway, responsible for utilization of plant-derived compounds. In contrast, this pathway in the other species is highly pseudogenized and consistent with the "domino theory" of gene death. There are distinct shared anomalous regions (SARs) found in both chromosomes as the result of horizontal gene transfer unique to Brucella and not shared with its closest relative Ochrobactrum, a soil bacterium, suggesting their acquisition occurred in spite of a predominantly intracellular lifestyle. In particular, SAR 2-5 appears to have been acquired by Brucella after it became intracellular. The SARs contain many genes, including those involved in O-polysaccharide synthesis and type IV secretion, which if mutated or absent significantly affect the ability of Brucella to survive intracellularly in the infected host.

The unusual inheritance of multidrug-resistance factors in Saccharomyces.

The yeast PDR5 locus encodes a 160-kDa member of the ABC family of transport proteins. Strains bearing a deletion of this locus are drug hypersensitive. Resistant revertants arise when cells are plated on cycloheximide medium. About one-third of these are cross resistant to other agents, including oligomycin, fluconazole and sulfometuron methyl. Most of the revertants exhibit linkage to the PDR5 locus and map in three locations. Curiously, the multi-drug resistance is not due to a single mutation. Most of the revertants behave as though they contained several tightly linked resistance factors.

Novel, quinone-thiosemicarbazone hybrid (QTSCHY) non-platinum antitumor agents: inhibition of DNA biosynthesis in P388 lymphocytic cells by coordinatively unsaturated copper(II) and iron(III) complexes of naphthoquinone thiosemicarbazones.

Coordinately unsaturated Cu(II) and Fe(III) complexes of the stoichiometry [Cu(L)Cl] and [Fe(L)Cl2], where L = tridentate anion of 2-hydroxy-1,4-naphthoquinone 1-thiosemicarbazone (2HNQTSC) and its 3-methyl derivative (3M2HNQTSC), were screened in vitro against P388 lymphocytic leukemia cells. Copper complexes were found to be more effective inhibitors of DNA synthesis than analogous Fe(III) compounds. The inhibitory activities are suggested to be related to Cu(II)-Cu(I) redox couple or nitrogen adduct formation.

Response of human chronic myeloid leukemia cells to mitoxantrone cytotoxicity: potentiation by bepridil, a calcium channel antagonist.

The ability of bepridil, a calcium channel blocker, to potentiate the antitumor activity of mitoxantrone (MITO) in human chronic myeloid leukemia (CML) cells was evaluated. MITO and bepridil, when incubated alone with the CML cells for 4 h, indicated a dose-dependent increase in the inhibition of 3H-thymidine incorporation. Incorporation rate of the radiolabeled thymidine into DNA was used as a measure of cell growth. When the CML cells were exposed to MITO (1 microgram/ml) in the presence of bepridil (1 and 5 micrograms/ml), an enhancement in the inhibition of DNA biosynthesis was observed in 14 out of 17 human CML samples studied. This significant inhibition (p less than 0.001) of 3H-thymidine incorporation due to the combination was found to be completely irreversible. Bepridil was identified predominantly in the octanol phase in the octanol/water partitioning studies. This lipophilic property of drug response modulators was implicated in the observed increase in the intracellular uptake of anticancer drugs, which in turn led to an enhanced cytotoxicity correlating well with the MITO activity observed in this study. The results are suggestive of clinical utility of bepridil as an adjuvant to enhance the anticancer ability of MITO in the treatment of CML.

Syntheses and spectroscopic studies of potential antitumor copper(II) complexes with 5-phenylazo-3-methoxy salicylidene thiosemicarbazone and N4 substituted thiosemicarbazones.

Five new copper(II) complexes of 5-phenylazo-3-methoxy salicylidene thiosemicarbazone and N4 substituted thiosemicarbazones have been synthesized. They have been characterized by chemical analyses, magnetic, conductance data, and by ultraviolet (UV)--visible, infrared, and electron spin resonance spectra. The complexes have the general formula CuL2, where HL is the ligand. One representative complex has been screened in vitro and in vivo against P388 lymphocytic leukemia cells sensitive and resistant to adriamycin (P388/S and P388/R). It has shown promising growth inhibition activity. We are reporting here for the first time the antineoplastic activity of this complex against experimental tumor systems.

Altered cerebral protein turnover in rats following prolonged in vivo treatment with nicotine.

Turnover rates of cerebral proteins were examined in control adult rats and in those subjected to prolonged in vivo treatment with "low" (0.02 mg/ml) or "high" (0.04 mg/ml) doses of nicotine (added to drinking water), using [14C]bicarbonate as the label. It was found that the turnover of proteins in various subcellular fractions consisted of two distinct components turning over at a "fast" or a "slow" rate and having relatively short or long half-lives, respectively. Thus in control animals the half-lives of the protein components turning over at a fast rate ranged from 1.31 to 3.61 days whereas for those turning over at a slow rate the half-lives ranged from 8.56 to 24.28 days. Treatment with low doses of nicotine resulted in a more rapid turnover of nuclear fast turning over component with a concomitant decreased turnover of homogenate, cytosol, mitochondrial, and microsomal proteins; in the synaptosomal membranes this component disappeared altogether. The half-lives of the slow turning over components decreased in general from 14.3 to 33.3% with the exception of the nuclear proteins, where the half-live increased by 71.1%. Turnover of microsomal proteins was not affected. When the animals were given a high dose of nicotine, the turnover of fast components became even more rapid for nuclear, myelin, and microsomal proteins with a decrease in half-life from 26.6 to 32.3%. By contrast, half-lives of synaptosomal and mitochondrial proteins increased by 16.1-89.3%. These changes were not reflected in the turnover rate of whole homogenate proteins.(ABSTRACT TRUNCATED AT 250 WORDS)

Altered synaptosomal ATPase activity in rat brain following prolonged in vivo treatment with nicotine.

Effects of prolonged in vivo treatment with nicotine on synaptosomal ATPase activity in rat brain were examined by employing doses of nicotine (0.02 and 0.04 mg/ml in the drinking water) which simulated intake by moderate and heavy smokers. Under these conditions the "low" dose of nicotine resulted in increased body weight whereas "high" dose of nicotine inhibited weight gain. Examination of synaptosomal ATPase activities revealed a dose and time dependent stimulatory/inhibitory effect. With "low" dose of nicotine, maximum stimulatory effect on ATPase activity was seen at the end of the 3rd week, while "high" dose stimulated the enzyme activities maximally by the 2nd week itself; further treatment up to the 4th week caused inhibition of the ATPase activities (10% to 43% decrease).