Hugo Delleon Silva

Why the Use of Adenoviruses as Water Quality Virologic Marker

Adenovirus is the virus that contains the highest amount of features favorable to its use as a virologic marker for water quality. Those pathogens are resistant on the environment, abundant, easily detected by molecular methods and are of great importance in public health.

Molecular Detection of Adenoviruses in Lakes and Rivers of Goiânia, Goiás, Brazil

Adenoviruses are a highly important public health issue, since they are among the most persistent and ubiquitous viruses present in water and associated with a variety of clinical manifestations. The aim of this study was to use molecular techniques for the detection of adenovirus in public and recreational water supplies in Goiânia, Brazil. From December 2007 to November 2008, 54 water samples were collected in 5 different sites in 2 lakes and 2 rivers of the city. The samples were filtered in a positively charged nylon membrane, and the DNA was extracted using the phenol–chloroform–isoamyl alcohol method. Semi-nested PCR was used to detect adenovirus DNA, and sequence analysis of the semi-nested PCR products was performed to identify the recovered viruses. Adenovirus DNA was detected in 43% (24 of 54) of samples collected. Considering all examined sites, MP1 presented the highest occurrence of adenovirus (6 positive from 10 collected samples), followed by MP2 (3 positive from 6 collected samples), JL (10 positive from 21 collected samples), VB (3 positive from 9 collected samples), and BB (2 positive from 8 collected samples), respectively. The methodology employed proved to be feasible, fast, low-cost, and suitable to be used as screening approach on adenovirus detection in water for public sanitation companies.

Cytotoxic and Genotoxic Effects of cis-Tetraammine(oxalato)Ruthenium(III) Dithionate on the Root Meristem Cells of Allium cepa

Ruthenium complexes have attracted much attention as possible building blocks for new transition-metal-based antitumor agents. The present study examines the mitotoxic and clastogenic effects induced in the root tips of Allium cepa by cis-tetraammine(oxalato)ruthenium(III) dithionate {cis-[Ru(C2O2)(NH3)4]2(S2O6)} at different exposure durations and concentrations. Correlation tests were performed to determine the effects of the time of exposure and concentration of ruthenium complex on mitotic index (MI) and mitotic aberration index. A comparison of MI results of cis-[Ru(C2O2)(NH3)4]2(S2O6) to those of lead nitrate reveals that the ruthenium complex demonstrates an average mitotic inhibition eightfold higher than lead, with the frequency of cellular abnormalities almost fourfold lower and mitotic aberration threefold lower. A. cepa root cells exposed to a range of ruthenium complex concentrations did not display significant clastogenic effects. Cis-tetraammine(oxalato)ruthenium(III) dithionate therefore exhibits a remarkable capacity to inhibit mitosis, perhaps by inhibiting DNA synthesis or blocking the cell cycle in the G2 phase. Further investigation of the mechanisms of action of this ruthenium complex will be important to define its clinical potential and to contribute to a novel and rational approach to developing a new metal-based drug with antitumor properties complementary to those exhibited by the drugs already in clinical use.

Behaviour and recovery of human adenovirus from tropical sediment under simulated conditions.

This study assessed the contributions of pH and organic matter (OM) on the recovery of infectious human adenovirus 5 (HAdV-5) and genome copies (GCs) in waters that were artificially contaminated with tropical soil. The use of a mathematical equation was proposed based on the flocculation index of clay to assess the recovery of total GCs in these controlled assays. The results suggest that solids in the water reduced the viral genome copy loads per millilitre (GC · mL(-1)) and viral infectivity. OM did not influence the GC · mL(-1) recovery rate (p > 0.05) but led to a 99% (2 log10) reduction in plaque-forming unit counts per millilitre (PFU/mL), which indicates that infectivity and gene integrity were non-related parameters. Our findings also suggest that acidic pH levels hinder viral inactivation and that clay is the main factor responsible for the interactions of HAdV-5 with soil. These findings may be useful for future eco-epidemiological investigations and studies of viral inactivation or even as parameters for future research into water quality analysis and water treatment.

Environmental Monitoring of Opportunistic Protozoa in Rivers and Lakes: Relevance to Public Health in the Neotropics

Water is a natural resource of vital importance to living beings, but due to anthropic action several microorganisms are disseminated into aquatic environments. In developing countries, over one billion people do not have access to clean, properly treated water and approximately three billion people do not have access to adequate sanitary facilities (Kraszewski et al., 2001) This scenery is probably a consequence of the increased environmental degradation, depletion of water resources, and constant contamination of bodies of water with wastewater and industrial effluents (Pedro & Germano, 2001), causing microorganisms from soil, faeces, decomposing organic matter, and other pollutant sources to spread into water. Goiania, the capital of the state of Goias, located in the Midwestern Region of Brazil, has ca. 1.221.654 inhabitants and is considered a regional metropolis, among the major Brazilian cities that receive a large number of migrants (Alves & Chaveiro 2007). As a result, the city faces problems of disorderly and unsustainable urban growth with a consequent increase in superficial waste, which is a continuous source of contamination of water courses. The current sources of public water supply for the city of Goiania, the Meia Ponte river basin and its tributary river Joao Leite, are constantly submitted to degradation processes due to anthropic action, such as agriculture, intensive livestock production, and urbanization. And although all the water supplies of Goiânia come from this basin (52% from the Joa o Leite River and 48% from the Meia Ponte River), this municipality is its largest polluter (Silva et al., 2010). Among the microorganisms that contaminate the aquatic environment, special attention should be given to opportunistic protozoa, such as Coccidea (Cryptosporidium parvum, Isospora belli, Sarcocystis sp., and Cyclospora sp.) and Microsporidia that infect the