Bacteriostatic and bactericidal modes of action of bis(tributyltin)oxide on Legionella pneumophila

Phosphoproteomic analysis of mouse thymoma cells treated with tributyltin oxide: TBTO affects proliferation and energy sensing pathways

We report the results of phosphoproteomic analysis of mouse thymoma cells treated with tributyltin oxide (TBTO), an immunotoxic compound. After cell lysis, phosphoproteins were isolated using Phosphoprotein Purification Kit, separated by SDS-PAGE and subsequently digested with trypsin. Phosphopeptides were enriched employing titanium dioxide, and the obtained fractions were analyzed by nano-LC-MS/MS. A total of 160 phosphoproteins and 328 phosphorylation sites were identified in thymoma cells. Among the differentially phosphorylated proteins identified in TBTO-treated cells were key enzymes, which catalyze rate-limiting steps in pathways that are sensitive to cellular energy status. These proteins included acetyl-CoA carboxylase isoform 1, which catalyzes the rate-limiting step of fatty acid synthesis. Another enzyme was glutamine: fructose-6-phosphate amidotransferase, GFAT1, the first and rate-limiting enzyme for the hexoamine synthesis pathway. Pyruvate dehydrogenase (PDH), a multicomplex enzyme that catalyzes the rate-limiting step of aerobic oxidation of fuel carbohydrates, was identified in both TBTO-treated and control cells; however, phosphorylation at residue S293, known to inhibit PDH activity, was identified only in control cells. A lower expression level of ribosomal protein S6 kinase 1, a downstream kinase of the mammalian target of rapamycin signaling pathway implicated in protein synthesis through phosphorylation of 40 ribosomal S6, was observed in the treated cells. Giant kinases like AMP-activated protein kinase (AMPK) and cAMP-dependent protein kinase (PKAR1A), which are known to mediate the phosphorylation of these enzymes, were identified in TBTO-treated cells. Downregulation of proteins, such as MAPK, matrin-3 and ribonucleotide reductase, subunit RRM2, which are implicated in cell proliferation, was also observed in TBTO-treated cells. Together, the results show that TBTO affects proliferation and energy sensor pathways.

Tributyltin oxide affects energy production in the yeast Rhodotorula ferulica, a utilizer of phenolic compounds

Rhodotorula ferulica, a yeast able to utilize phenolic compounds, was chosen for evaluating the effects of tributyltin oxide (TBTO) on this utilization. TBTO reduced respiratory capacity when vanillic or benzoic acid was the energy source. The ATP level of the cells was severely affected by 2 microM TBTO. The mitochondrial ATPase was strongly inhibited by 0.5 microM TBTO, whereas the activity of the plasma membrane ATPase was not affected by concentrations of TBTO up to 30 microM. Our data support the hypothesis that the target for TBTO action is the mitochondrial ATPase, resulting in a severe disturbance of the yeast utilization of aromatic compounds.

Ecology of Legionella: From Data to Knowledge with a Little Wisdom

The respiratory diseases produced by the Legionella genus of bacteria are collectively called Legionellosis. Presently more than 34 species of Legionella have been identified, 20 of which have been isolated from both environmental and clinical sources. The diseases produced by Legionella include the pneumonic form, Legionnaires' disease, and the flu-like form, Pontiac fever. Because the vast majority of Legionellosis is caused by the L. pneumophila species, this bacterium is the thrust of the discussion.Legionella is a global bacterium. The relationship of the bacterium to its environment has told us many things about infectious diseases. Not until Legionellosis and the discovery of its etiologic agent, Legionella, has such a successful modern-day marriage been consummated between the agent and its environment. Nearly two decades have passed since the term Legionellosis found its way into the vocabulary of the scientific journals, the popular press, and courtroom proceedings. Too often the scientific development, engineering implementation, and societal acceptance are disconnected. The focus of scientific research sometimes does not reflect engineering or societal needs and thus contributes little to the solution of immediate and important problems. At other times, scientific knowledge that could contribute to solutions is overlooked because of poor communication between the problem holders, the scientific community, regulatory agencies, the problem makers, and the public. The scope of this paper provides insights on the ecological niche of Legionella, describes the organism's ecological relationships in the natural world, and provides wisdom for effective control of the bacterium for the industrial and user communities.

Toxicity of dibutyltin, tributyltin and other organotin compounds to humans and to experimental animals

Alkyltin compounds are used as stabilizers and antifouling agents. Food chain accumulation and bioconcentration have been demonstrated in crabs, oysters and salmon exposed to tributyltin oxide. In mammalian species, tributyltin compounds may be metabolized to dibutyltin derivatives and related metabolites. Di- and tributyltins appear to be less potent neurotoxicants than trimethyltins and triethyltins. Dibutyltins and tributyltins produced bile duct damage in rats, mice and hamsters. Tributyltin oxide and dibutyltin and dioctyltin compounds are potent thymolytic and immunotoxic agents in rats. Tributyltin oxide at 5 ppm in the rat diet produced immunotoxicity in a 2-year feeding study, and at 50 ppm increased the incidence of tumors of endocrine origin. In preliminary reports, 5 ppm tributyltin produced no detectable increase in tumor incidence, and 0.5 ppm produced no detectable immunotoxicity in long-term studies. Tributyltin oxide and dibutyltin acetate did not appear to be mutagenic in a large battery of mutagenicity assays but produced base-pair substitutions in one of the bacterial strains tested. Tributyltin oxide produced mutations in Chinese hamster ovary cells, increased the incidence of micronuclei in the erythrocytes of exposed male BALB/c mice, and was highly embryotoxic in vitro. Embryotoxic and teratogenic effects in mice exposed to tributyltin oxide in vivo may have been due either to direct tributyltin oxide action or responses secondary to maternal toxicity. More information is needed to determine the applicability to human risk assessments of the immunotoxicity data derived from rat studies and to establish a definitive tolerable daily intake for tributyltin oxide.

Legionella and Legionnaires' disease: a review with emphasis on environmental studies and laboratory diagnosis

Legionella pneumophila and related species are important causes of epidemic bacterial pneumonia and nosocomial infection. This review will discuss this new family of bacteria and the diseases they produce. The classification, general microbiologic characteristics, and ecology of the bacteria will be reviewed and the epidemiology and clinical aspects of the infection will be discussed. More emphasis will be given to issues that are more directly related to laboratory workers and with which the author has had more direct experience: pathology, laboratory diagnosis of human infection, pathogenesis of the infection, and virulence mechanisms of the bacterium. Therapy and prevention of the infection will be discussed more briefly.

Comparison of methods to measure acute metal and organometal toxicity to natural aquatic microbial communities

Microbial communities in water from Baltimore Harbor and from the mainstem of Chesapeake Bay were examined for sensitivity to mercuric chloride, monomethyl mercury, stannic chloride, and tributyltin chloride. Acute toxicity was determined by measuring the effects of [3H]thymidine incorporation, [14C]glutamate incorporation and respiration, and viability as compared with those of controls. Minimum inhibitory concentrations were low for all metals (monomethyl mercury, less than 0.05 microgram liter-1; mercuric chloride, less than 1 microgram liter-1; tributyltin chloride, less than 5 micrograms liter-1) except stannic chloride (5 mg liter-1). In some cases, mercuric chloride and monomethyl mercury were equally toxic at comparable concentrations. The Chesapeake Bay community appeared to be slightly more sensitive to metal stress than the Baltimore Harbor community, but this was not true for all treatments or assays. For culturable bacteria the opposite result was found. Thymidine incorporation and glutamate metabolism were much more sensitive indicators of metal toxicity than was viability. To our knowledge, this is the first use of the thymidine incorporation method for ecotoxicology studies. We found it the easiest and fastest of the three methods; it is at least equal in sensitivity to metabolic measurements, and it likely measures the effects on greater portion of the natural community.

Susceptibilities of algae and Legionella pneumophila to cooling tower biocides

Nine algal strains and nine Legionella pneumophila strains were tested in laboratory culture for their susceptibility to inhibition by a variety of commercially available microbiocides. The responses ranged from ineffective to effective at 1/100 the manufacturers' recommended pulse doses. Tests were also performed to determine whether the action of the microbiocide was bacteriostatic or bacteriocidal.