The complete genome sequence of Chromobacterium violaceum reveals remarkable and exploitable bacterial adaptability

Chromobacterium violaceum is one of millions of species of free-living microorganisms that populate the soil and water in the extant areas of tropical biodiversity around the world. Its complete genome sequence reveals (i) extensive alternative pathways for energy generation, (ii) ≈500 ORFs for transport-related proteins, (iii) complex and extensive systems for stress adaptation and motility, and (iv) wide-spread utilization of quorum sensing for control of inducible systems, all of which underpin the versatility and adaptability of the organism. The genome also contains extensive but incomplete arrays of ORFs coding for proteins associated with mammalian pathogenicity, possibly involved in the occasional but often fatal cases of human C. violaceum infection. There is, in addition, a series of previously unknown but important enzymes and secondary metabolites including paraquat-inducible proteins, drug and heavy-metal-resistance proteins, multiple chitinases, and proteins for the detoxification of xenobiotics that may have biotechnological applications.

Toxic and genotoxic effects of trivalent and hexavalent chromium - A review

During the last years, the emission of heavy metals to the environment has increased, causing a severe negative impact to the ecosystems and seriously compromising human health due to their mutagenic potential. Tri- (III) and hexavalent (VI) chromium (Cr) constitute the oxidative states of the metal chromium that are active in living organisms. These two oxidation states of the chromium differ with regards to their cellular effects, mainly due to the different abilities they possess in relation to easy of transport through biological membranes. Cr VI is transported into the cell through transference channels of endogenous anions that are isostructural and isoelectronical to Cr VI, such as SO 4 -2 and HPO 4 -2. On the other hand, Cr III is unable to diffuse through the cell membrane. Its existence inside the cells is generally due to the reduction of Cr VI, the endocytosis, or the absortion by the cells via phagocytosis. Cr III acts directly on the DNA molecule, while Cr VI reacts little with this molecule. In the ecosystem, however, Cr VI is more dangerous since this is the form that presents greater reactivity with biological membranes, crossing them and being easily incorporated into the cell. In the cell it is biotransformed to Cr III, a potentially mutagenic molecule. In vivo and in vitro studies have shown that organisms exposed to Cr VI present greater induction to a variety of damages to the DNA molecule. Among the damages induced by Cr, changes in the structure of the DNA molecule have been reported, with breaks of the major chain and base oxidation. In the organisms, these alterations generate chromosomal aberrations, micronucleus formation, sister chromatid exchanges, and errors in DNA synthesis.

The structural origin and biological function of pH-sensitivity in firefly luciferases

Firefly luciferases are called pH-sensitive because their bioluminescence spectra display a typical red-shift at acidic pH, higher temperatures, and in the presence of heavy metal cations, whereas other beetle luciferases (click beetles and railroadworms) do not, and for this reason they are called pH-insensitive. Despite many studies on firefly luciferases, the origin of pH-sensitivity is far from being understood. This subject is revised in view of recent results. Some substitutions of amino-acid residues influencing pH-sensitivity in firefly luciferases have been identified. Sequence comparison, site-directed mutagenesis and modeling studies have shown a set of residues differing between pH-sensitive and pH-insensitive luciferases which affect bioluminescence colors. Some substitutions dramatically affecting bioluminescence colors in both groups of luciferases are clustered in the loop between residues 223-235 (Photinus pyralis sequence). A network of hydrogen bonds and salt bridges involving the residues N229-S284-E311-R337 was found to be important for affecting bioluminescence colors. It is suggested that these structural elements may affect the benzothiazolyl side of the luciferin-binding site affecting bioluminescence colors. Experimental evidence suggest that the residual red light emission in pH-sensitive luciferases could be a vestige that may have biological importance in some firefly species. Furthermore, the potential utility of pH-sensitivity for intracellular biosensing applications is considered. © The Royal Society of Chemistry and Owner Societies.

Mercury, copper, and zinc concentrations in extracted human teeth

Amalgam has been used as a filling material for over 150 years. Mercury, copper, and zinc are present in restoration. The aim of this study was to compare mercury, copper, and zinc concentrations in extracted human teeth with amalgam restorations and teeth without restorations. Thirty-two teeth, 15 restored with dental amalgam and 17 without restorations, were chemically analyzed in an Optima 3300 DV (Perkin Elmer) plasma emission spectrometer. Mercury, copper, and zinc were found in human teeth regardless of the presence of amalgam restorations. The highest mercury concentrations were found in the coronary portions of the teeth with amalgam restorations. Copper concentrations were very high. Zinc concentrations in the teeth without restoration were lower than those seen in the coronary portion of the teeth with restorations. © 2009 Heldref Publications.

The effects of soil pollution and its relation with morbidity in shoreline areas

Soil and subsoil pollution is not only significant in terms of environmental loss, but also a matter of environmental and public health. Solid, liquid and gaseous residues are the major soil contamination agents. They originate from urban conglomerates and industrial areas in which it is impossible to emphasize the chemical, petrochemical and textile industry; thermoelectric, mining, and ironmaster activities. The contamination process can thus be defined as a compound addition to soil, from what qualitative and or quantitative manners can modify soil's natural characteristics and use, producing baneful and deteriorative effects on human health. Studies have shown that human exposition to high concentration of some heavy metals found on soil can cause serious health problems, such as pulmonary or kidney complications, liver and nervous system harm, allergy, and the chronic exposition that leads to death. The present study searches for the correlation among soil contamination, done through a geochemical baseline survey of an industrial contamination area on the shoreline of Sao Paulo state. The study will be conducted by spatial analysis using Geographical Information Systems for mapping and regression analysis. The used data are 123 soil samples of percentage concentration of heavy metals. They were sampled and spatially distributed by geostatistics methods. To verify if there is a relation between heavy metals soil pollution and morbidity an executed correlation and regression analysis will be done using the pollution registers as the independent variables and morbidity as dependable variables. It is expected, by the end of the study, to identify the areas relation between heavy metals soil pollution and morbidity, moreover to be able to provide assistance in terms of new methodologies that could facilitate soil pollution control programs and public health planning. © 2010 WIT Press.

Study of adsorption and preconcentration by using a new silica organomodified with [3-(2,2′-dipyridylamine)propyl] groups

In this work, a silica surface chemically modified with [3-(2,2′-dipyridylamine)propyl] groups, named [3-(2,2′- dipyridylamine)propyl]silica (Si-Pr-DPA) was prepared, characterized, and evaluated for its heavy metal adsorption characteristics from aqueous solution. To our knowledge, we are the first authors who have reported the present modification. The material was characterized using infrared spectroscopy, SEM, and NMR 29Si and 13C solid state. Batch and column experiments were conducted to investigate for heavy metal removal from dilute aqueous solution by sorption onto Si-Pr-DPA. From a number of studies the affinity of various metal ions for the Si-Pr-DPA sorbent was determined to follow the order Fe(III) > Cr(III) >> Cu(II) > Cd(II) > Pb(II) > Ni(II). Two standard reference materials were used for checking the accuracy and precision of the method. The proposed method was successfully applied to the analysis of environmental samples. This ligand material has great advantage for adsorption of transition-metal ions from aqueous medium due to its high degree of organofunctionalization associated with the large adsorption capacity, reutilization possibility, and rapidity in reaching the equilibrium. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Concentrations of Cu, Fe, Mn, and Zn in tropical soils amended with sewage sludge and composted sewage sludge

Sewage sludge may be used as an agricultural fertilizer, but the practice has been criticized because sludge may contain trace elements and pathogens. The aim of this study was to compare the effectiveness of total and pseudototal extractants of Cu, Fe, Mn, and Zn, and to compare the results with the bioavailable concentrations of these elements to maize and sugarcane in a soil that was amended with sewage sludge for 13 consecutive years and in a separate soil that was amended a single time with sewage sludge and composted sewage sludge. The 13-year amendment experiment involved 3 rates of sludge (5, 10, and 20 t ha-1). The one-time amendment experiment involved treatments reflecting 50, 100, and 200 % of values stipulated by current legislation. The metal concentrations extracted by aqua regia (AR) were more similar to those obtained by Environmental Protection Agency (EPA) 3052 than to those obtained by EPA3051, and the strongest correlation was observed between pseudo(total) concentrations extracted by AR and EPA3052 and bioavailable concentrations obtained by Mehlich III. An effect of sewage sludge amendment on the concentrations of heavy metals was only observed in samples from the 13-year experiment. © 2012 Springer Science+Business Media B.V.

The effects of different styles of musical auditory stimulation on cardiac autonomic regulation in healthy women

The literature investigated the effects of chronic baroque music auditory stimulation on the cardiovascular system. However, it lacks in the literature the acute effects of different styles of music on cardiac autonomic regulation. To evaluate the acute effects of baroque and heavy metal music on heart rate variability (HRV) in women. The study was performed in 21 healthy women between 18 and 30 years old. We excluded persons with previous experience with music instrument and those who had affinity with the song styles. All procedures were performed in the same sound-proof room. We analyzed HRV in the time (standard deviation of normal-to-normal respiratory rate (RR) intervals, root-mean square of differences between adjacent normal RR intervals in a time interval, and the percentage of adjacent RR intervals with a difference of duration greater than 50 ms) and frequency (low frequency [LF], high frequency [HF], and LF/HF ratio) domains. HRV was recorded at rest for 10 min. Subsequently they were exposed to baroque or heavy metal music for 5 min through an earphone. After the first music exposure they remained at rest for more 5 min and them they were exposed again to baroque or heavy metal music. The sequence of songs was randomized for each individual. The power analysis provided a minimal number of 18 subjects. Shapiro-Wilk to verify normality of data and analysis of variance for repeated measures followed by the Bonferroni test for parametric variables and Friedman's followed by the Dunn's post-test for non-parametric distributions. During the analysis of the time-domain indices were not changed. In the frequency-domain analysis, the LF in absolute units was reduced during the heavy metal music stimulation compared to control. Acute exposure to heavy metal music affected the sympathetic activity in healthy women.

Nonlinear Optical Properties of Tungsten Lead-Pyrophosphate Glasses Containing Metallic Copper Nanoparticles

We have prepared heavy metal oxide glasses containing metallic copper nanoparticles with promising nonlinear optical properties which were determined by Z-scan and pump-probe measurements using femtosecond laser pulses. For the wavelengths within the plasmon band, we have observed saturable absorption and response times of 2.3 ps. For the other regions of the spectrum, reverse saturable absorption and lifetimes shorter than 200 fs were verified. The nonlinear refractive index is about 2.0 × 10-19 m2/W from visible to telecom region, thus presenting an enhancement effect at wavelengths near the plasmon and Cu+2 d-d band. © 2013 Springer Science+Business Media New York.

Adubação mineral, esterco de curral e lodo de esgoto no desenvolvimento inicial do cafeeiro

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Utilização de escamas e Eichhornia crassipes no tratamento de efluente de curtume de peles de tilápias

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Potencial do eucalipto na fitorremediação de um solo contaminado por chumbo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Ação citoprotetora do óxido nítrico na germinação de arroz (Oryza sativa L.) e soja (Glycine max (L.)Merril)submetidas a estresse de alumínio

Pós-graduação em Ciências Biológicas (Botânica) - IBB

Avaliação do potencial de compostos naturais (argila, turfa e carvão) na remoção do Chumbo (Pb) e da toxicidade de um efluente industrial

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Utilização de lodo de esgoto compostado e irrigação com água residuária em laranjeira valência

Pós-graduação em Agronomia (Irrigação e Drenagem) - FCA