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Watersheds are defined as a set of lands where water drainage occurs through rivers and their tributaries. A large quantity of water resources exist in the state of Maranhão, Brazil, where rivers and their basins must meet environmental quality standards defined by the limits set out in national environmental council (CONAMA) legislation 357/05 for physicochemical and microbiological parameters, including parasites. Multivariate statistical techniques were applied to study the temporal and spatial variations in water quality of a segment of the Pindaré River. The data set included nine parameters for three sampling points over eleven months. Principal component analysis grouped the monitored sampling points into four clusters and identified electrical conductivity, temperature, total dissolved solids (TDS), pH, salinity, and Escherichia coli as being associated with the dry season and nitrite, nitrate, and turbidity as being associated with the rainy season. Three principal components explained 83.80% of the data variance during the rainy and dry seasons. The evaluated correlations indicated that during the rainy season, nitrite (~0.18 mg L−1) and turbidity (~46.00 NTU) levels were the highest, but pH was at its lowest (~6.61). During the dry season, TDS (~155.00 mg L−1) and pH (~8.10) were highest, and E. coli bacteria was more abundant. [ABSTRACT FROM AUTHOR]

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Objective The present study assessed the effect of smoking on clinical, microbiological and immunological parameters in an experimental gingivitis model. Material and Methods Twenty-four healthy dental students were divided into two groups: smokers ( n = 10); and nonsmokers ( n = 14). Stents were used to prevent biofilm removal during brushing. Visible plaque index ( VPI) and gingival bleeding index ( GBI) were determined 5- on day -7 (running phase), baseline, 21 d (experimental gingivitis) and 28 d (resolution phase). Supragingival biofilm and gingival crevicular fluid were collected and assayed by checkerboard DNA- DNA hybridization and a multiplex analysis, respectively. Intragroup comparison was performed by Friedman and Dunn's multiple comparison tests, whereas the Mann-Whitney U-test was applied for intergroup analyses. Results Cessation of oral hygiene resulted in a significant increase in VPI, GBI and gingival crevicular fluid volume in both groups, which returned to baseline levels 7 d after oral hygiene was resumed. Smokers presented lower GBI than did nonsmokers ( p < 0.05) at day 21. Smokers had higher total bacterial counts and higher proportions of red- and orange complex bacteria, as well as lower proportions of Actinomyces spp., and of purple- and yellow-complex bacteria ( p < 0.05). Furthermore, the levels of key immune-regulatory cytokines, including interleukin ( IL)-8, IL-17 and interferon-γ, were higher in smokers than in nonsmokers ( p < 0.05). Conclusion Smokers and nonsmokers developed gingival inflammation after supragingival biofilm accumulation, but smokers had less bleeding, higher proportions of periodontal pathogens and distinct host-response patterns during the course of experimental gingivitis. [ABSTRACT FROM AUTHOR]

Aim To evaluate the changes occurring in the subgingival microbial profile of subjects with generalized chronic periodontitis (ChP) treated by scaling and root planing ( SRP) alone or with metronidazole ( MTZ) or MTZ + amoxicillin ( AMX). A secondary aim was to examine a possible added effect of chlorhexidine ( CHX) to these therapies. Methods One hundred and eighteen subjects were randomly assigned to receive SRP-only or with MTZ [400 mg/thrice a day ( TID)] or MTZ + AMX (500 mg/ TID) for 14 days. Half of the subjects in each group rinsed with 0.12% CHX twice a day ( BID) for 2 months. Nine subgingival plaque samples/subject were analysed by checkerboard DNA- DNA hybridization for 40 bacterial species at baseline, 3, 6 and 12 months post-therapy. Results At 12 months, the antibiotic-treated groups harboured lower mean counts and proportions of key periodontal pathogens than the SRP group ( p < 0.05). These benefits were observed at initially deep and shallow sites. Initial reductions in periodontal pathogens obtained with SRP partially rebound after 12 months. CHX rinsing enhanced the microbiological effects of the MTZ + AMX treatment in shallow sites. Conclusion The adjunctive use of MTZ and MTZ + AMX results in a greater reduction in the levels of periodontal pathogens in generalized ChP subjects compared to SRP alone. [ABSTRACT FROM AUTHOR]

Papaya ringspot virus-type W (PRSV-W) is the most prevalent and important viral pathogen of cucurbits in Brazil. It can be effectively controlled by the incorporation of genetic resistance into susceptible melon cultivars. The present study identified amplified fragment length polymorphic (AFLP) markers linked to the PRSV-W resistance Prv1 allele. The susceptible yellow-fleshed melon-breeding line AF426 prv1 and its nearly isogenic-resistant line AF426 Prv1, which carries the Prv1 allele resident in the Indian cantaloupe U.S. Plant Introduction (PI) 180280, were screened for AFLP marker polymorphisms. Of 30 251 AFLP loci, only three were polymorphic between the nearly isogenic lines. Segregation analyses for these three polymorphic markers and the Prv1 allele using a BC1 population of 197 plants indicated close linkage (0.5% recombination frequency) between marker EK190 ( HindIII-CGA and MseI-GTG; 190 bp) and Prv1. Thus, EK190 might be a useful marker in breeding programmes aiming to develop melon cultivars resistant to PRSV-W. The other two markers are closely linked to each other, but distantly linked to Prv1. [ABSTRACT FROM AUTHOR]