Induced alkoxyresorufin-O-dealkylases in tilapias (Oreochromis niloticus) from Guandu river, Rio de Janeiro, Brazil

The activity of fish monooxygenases has been extensively used as a monitoring tool to detect contamination of water bodies by cytochrome P450-inducing agents. In this study we evaluated the activities of ethoxy- (EROD), methoxy- (MROD) and pentoxy- (PROD) resorufin-O-dealkylases in the liver of Nile tilapias (Oreochromis niloticus) collected at the Guandu river, at a reference clean site (Lake 1) and at two other sampling sites (Lakes 2 and 3) in Rio de Janeiro state, Brazil. Alkoxyresorufin-O-dealkylases were measured fluorimetrically in the hepatic S9 fraction. EROD (17.7-fold), MROD (14.2-fold) as well as PROD activities were considerably higher in tilapias from Guandu river. A moderate increase of EROD (5.0-fold) and MROD (5.4-fold) was also found in tilapias from Lake 3. These findings suggest that Guandu river watershed, the main source of urban drinking water supply in Rio de Janeiro, is polluted with CYP1A-inducing xenobiotics. Furthermore, we also found a good linear relationship between EROD and MROD, a finding that agrees with the hypothesis that the two reactions are catalysed by the same CYP1A isoform in O. niloticus.     

Modulation of branchial ion transport protein expression by salinity in glass eels (<Emphasis Type="Italic">Anguilla anguilla</Emphasis> L.)

The Anguillid juvenile glass eel must deal with the osmoregulatory consequences of highly variable environmental salinities on its recruitment migration from coastal to fresh waters. Changes in ionoregulatory parameters and branchial ion transport protein [Na⁺/K⁺-ATPase, Na⁺:K⁺:2Cl⁻ cotransporter (NKCC), cystic fibrosis transmembrane regulator (CFTR) anion channel, V-type proton ATPase] expression (activities, protein and/or mRNA level expression and/or cellular localization) in response to acclimation to a broad range of ionic strengths [distilled water (DW) to hypersaline water (HSW; 150%) sea water (SW 32‰)] was studied. The estuarine glass eels were very euryhaline and successfully acclimated to acute changes in environmental ionic strength from 50% SW, with high mortality only observed in HSW (51%) and sublethal osmoregulatory indicators (whole body water content and sodium levels) disturbed at the extremes (DW and HSW). Central to a high salinity acclimation were elevated branchial Na⁺/K⁺-ATPase, NKCC and CFTR expression. At lower salinity, Na⁺/K⁺-ATPase expression was maintained and NKCC and CFTR expressions were reduced. Branchial chloride cells increased in size up to SW but decreased in HSW. During hypotonic disturbance (DW), no compensatory elevation in V-ATPase or Na⁺/K⁺-ATPase expression was observed.     

Biodegradation of wastewater of Najafgarh drain,Delhi using autochthonous microbial consortia : a laboratory study

There are seventeen drains, which discharge their untreated urban and industrial wastewaters into the Delhi segment of river Yamuna. The Najafgarh drain is the first and the largest drain, and it alone contributes 1667.84 mld i.e. 60% of the total wastewater discharge into the river Yamuna and as such add 81.36 tons of BOD load per day. As per the available data approximately 95% of the wastewater of this drain is biodegradable. In the present study, an attempt has been made to reduce the BOD load and COD levels of wastewater of Najafgarh drain using autochthonous microbial consortium. During this study the raw wastewater samples were treated for 6 h time interval with different concentration of consortium. It was observed that by increasing the existing microbial population in the wastewater sample by 150-200% there is a significant decrease in BOD and COD levels. Finally, BOD/COD ratios before and after biotreatment have been analyzed to assess the efficacy of the natural consortium.     

Temporal and spatial variation in the growth rates of Baltic herring (<Emphasis Type="Italic">Clupea harengus membras</Emphasis> L.) larvae during summer

It has been suggested that larval survival determines the year-class strength in most marine fish species. During their growth and development, the ability of the larvae to catch prey and avoid predation will increase. However, the factors affecting short-term changes in the growth of Baltic Sea herring have been little studied in the field. We collected Baltic herring (Clupea harengus membras L.) larvae from five different towing areas in the Archipelago Sea (SW Finland) during May and June 1989, right after the main spawning season. Twenty thousand two hundred and ten larvae were analysed and the area-specific growth rate (i.e. increase in standard length) was estimated by tracing the larval cohorts from the length-frequency data. This represents the first Baltic herring study with daily sampling during a long study period. The growth rate was related to environmental factors, such as temperature, number of zooplankters, and wind speed and direction. Large variation in larval growth rate occurred between areas: lowest and highest growth rates were 0.18 and 0.52 mm·day^-1. Temperature was an important variable controlling larval-fish growth rate. An increase of one 1°C in average water temperature corresponded to an increase in growth rate of 0.043 mm·day^-1. This may have been caused either by a direct temperature effect (changes in metabolic rate) or by the indirect effect of changes in food availability. We also found the densest herring populations in the areas with highest average water temperature. However, temperature and larval growth rate both increased towards the inner archipelago.     

Ovary development at the onset of gametogenesis is genetically determined and correlated with reproductive traits at maturity in shrimp <Emphasis Type="Italic">Litopenaeus (Penaeus) vannamei</Emphasis>

Besides some mammals and a few model organisms, the presence of genetic variation in ovary or gonad development at ages before that of reproduction has not been established for marine oviparous species nor has the correlation with reproductive traits at maturity. In this investigation, ovary development was evaluated for genetic variability in a full-sib family structured population of subadult shrimp. The numbers of each oocyte type that were present were counted, measured, and used to evaluate the following traits: total oocyte number, mean oocytes diameter, and ovary maturity (OM). The total ovary area was also measured for each female. Genetic variation was assessed through the estimation of the parameter ‘heritability’. The heritability (h ²) of total number of oocytes was zero, but large heritability values were seen for mean oocytes diameter (h ²=0.57±0.27) and OM (h ²=0.71±0.26). Family means correlations between traits in subadults with traits measured in their full-sibs when adults (days to first spawn, total number of spawns, total fecundity, and fecundity at first spawn) indicated the existence of some significant associations between reproductive traits at the two ages. These findings point toward an early genetic determination of reproductive capacity in this crustacean.     

Environmental Surveillance of Enteroviruses in Central Argentina: First Detection and Evolutionary Analyses of E14

Environmental surveillance is an effective approach to investigate the circulation of human enteroviruses in the population. Enteroviruses E14, CVA9, E-6, E16, E20, E25, E13, and CVA24 were detected in sewage and a watercourse in central Argentina. E14 was the most frequent serotype and was found for the first time in environmental samples in our region. Phylogenetic and coalescence analyses showed at least two recent introduction events.     

Identifying Conservation and Restoration Priorities for Saproxylic and Old-Growth Forest Species: A Case Study in Switzerland

Saproxylic (dead-wood-associated) and old-growth species are among the most threatened species in European forest ecosystems, as they are susceptible to intensive forest management. Identifying areas with particular relevant features of biodiversity is of prime concern when developing species conservation and habitat restoration strategies and in optimizing resource investments. We present an approach to identify regional conservation and restoration priorities even if knowledge on species distribution is weak, such as for saproxylic and old-growth species in Switzerland. Habitat suitability maps were modeled for an expert-based selection of 55 focal species, using an ecological niche factor analyses (ENFA). All the maps were then overlaid, in order to identify potential species’ hotspots for different species groups of the 55 focal species (e.g., birds, fungi, red-listed species). We found that hotspots for various species groups did not correspond. Our results indicate that an approach based on “richness hotspots” may fail to conserve specific species groups. We hence recommend defining a biodiversity conservation strategy prior to implementing conservation/restoration efforts in specific regions. The conservation priority setting of the five biogeographical regions in Switzerland, however, did not differ when different hotspot definitions were applied. This observation emphasizes that the chosen method is robust. Since the ENFA needs only presence data, this species prediction method seems to be useful for any situation where the species distribution is poorly known and/or absence data are lacking. In order to identify priorities for either conservation or restoration efforts, we recommend a method based on presence data only, because absence data may reflect factors unrelated to species presence.     

Biosorption of Reactive Black 5 from aqueous solutions by chitosan: Column studies

Fixed-bed column studies were carried out to investigate the dynamic sorption of Reactive Black 5 (RB5) onto chitosan. The effect of operating parameters such as initial dye concentration, superficial flow velocity, bed height and particle size on the sorption of RB5 onto chitosan was studied. Column regeneration, dye recovery and the possibility of reusing the regenerated chitosan were also investigated. The results show that both the breakthrough curves and the adsorption parameters of the column were strongly affected by the operating parameters studied. An analysis of the breakthrough curves indicated that adsorption was affected by mass transfer limitations, probably due to intraparticle diffusion. An empirical model was applied to describe the breakthrough curves, while the Bohart–Adams and BDST models were used to determine the operating parameters useful in the process design. Elution of the column with 0.01 mol L^?1 NaOH allowed the chitosan to be regenerated and the dye to be recovered and concentrated. The concentration factor was 10. Several cycles of adsorption–elution showed that the regenerated chitosan retained good adsorption efficiency and the elution efficiency was always higher than 80%.