Intracellular localization and binding of technetium-95m in the seastar Marthasterias glacialis

The subcellular distribution of technetium was studied using the seastar Marthasterias glacialis which had previously ingested prey labelled with ^95mTc either as pertechnetate (VII) or in the reduced state (IV). The majority of the Tc [98% (IV) and 96% (VII)] was taken up and retained in the pyloric caeca, the gland responsible for digestive and food storage processes. Differential centrifugation and separation techniques have demonstrated that, at the subcellular level, technetium in the pyloric caeca was largely associated with the lysosomes. ^95mTc (IV) was distributed between the lysosomes and the soluble fraction to roughly the same degree, whereas pertechnetate was more strongly associated with the lysosomal fraction. Chromatography of the cytosol by gel filtration indicated the presence of two distinct protein compounds which were responsible for binding virtually all of the technetium in the soluble fraction. Technetium had a greater relative affinity for the low molecular weight compound, more so for Tc (VII) than for Tc (IV). This anionic protein had an apparent molecular weight of approximately 10 000, and thus may play a role in metal detoxification mechanisms at the cellular level.     

Intracellular digestion in two sublittoral populations of Ostrea edulis (Lamellibranchia)

The rhythmicity of intracellular digestion was examined in two sublittoral populations of Ostrea edulis L. On the West coast of Ireland. During 12 h cycles at each station, 20 oysters were collected each hour, grouped as sub-samples of 5, facing each of the 4 cardinal points of the compass. A segment of digestive diverticula from each oyster was examined histologically and classified according to the digestive phases of the tubules. Oysters at both stations exhibited fluctuations in digestive activity which were not correlated with tidal ebb and flow nor with orientation to tidal currents. A relationship between variations in suspended particulate matter concentration in the water body and digestion is proposed. It is suggested that increases in the levels of particulate matter, by stimulating feeding, cause a significant increase in the proportion of absorptive-phase tubules 4 to 6 h later.     

Differential responses of benthic microbes and meiofauna to fish-farm disturbance in coastal sediments

Bacterial and meiofaunal abundance and biomass and their response to the disturbance induced by fish-farm biodeposition were investigated from March to October 1997 on a monthly basis at two stations of the Gaeta Gulf (Tyrrhenian Sea, Mediterranean Sea). The biopolymeric fraction of the organic matter was characterized by high concentrations which was similar at both fish-farming-impacted and control stations. Similarly, bacteria accounted for a small fraction of the biopolymeric organic carbon (< 1%), while the contribution due to auto-fluorescent cell biomass (i.e. prokaryotic and eukaryotic cells displaying auto-fluorescence) to the total biopolymeric carbon was quantitatively negligible (< 0.1%). Benthic bacteria appear to be sensitive to organic enrichment as their abundance increased significantly beneath the cage, whilst numbers of meiofauna was lower than in the control. Changes occurred also in terms of individual nematode biomass that increased as result of the biodeposition. A particularly useful tool appeared to be represented by the ratio of benthic auto-fluorescent cells to bacterial abundance, bacteria to meiofaunal biomass and auto-fluorescent cells to meiofauna biomass. All these parameters described well the impact due to biodeposition on the benthic environment as their ratios displayed significantly higher values in farm sediments, but recovered rapidly (15 days) to values observed in the control (i.e. undisturbed conditions) immediately after cage removal. Changes observed in the present study highlight that the increased organic loading determined a shift of the relative contribution of the different benthic components to the total biopolymeric carbon, so that in highly impacted systems total benthic biomass becomes increasingly dominated by microbial components.     

First evaluation of the Brazilian microorganisms biocatalytic potential

The biocatalytic potential of two novel Brazilian strains of Aspergillus niger and Rhodotorula glutinis, revealed enantioselective epoxide hydrolase activity in the asymmetrization of meso-epoxide and monosubstituted epoxides respectively. These two types of oxirane derivatives are not usually good substrates for biocatalytic enantioselective conversion.     

Impact of sublethal doses of 2,4-D, simulating drift, on tomato yield

Tomato is considered one of the most sensitive crops regarding 2,4-D drift. In many cases, such susceptibility has led to important restrictions in the use of 2,4-D based products. Field experiments were carried out for two consecutive years in tomato, by applying sublethal doses of 2,4-D (ranging from 0.42 to 13.44 g a.i. ha(-1)) directly to plants, at different stages of growth, as a simulation of eventual drifts to the crop. The range of rates was based on the assumption of a 0.0625-2.0% drift level of a 1 L ha(-1) of the most common formulated herbicides. For this crop, the range of rates between 0.42 and 13.44 g a.i ha(-1) applied at the beginning of flowering caused a linear crop reduction. On the other hand, rates < or = 13.44 g a.i. ha(-1) applied after full development of fourth truss stage or latter had no effect on crop yield or development. For tomato, tolerance to 2,4-D strongly increases with plant age.     

Enhancement of conservation knowledge through increased access to botanical information

Herbarium specimens are increasingly recognized as an important resource for conservation science and virtual herbaria are making specimens freely available to a wider range of users than ever before. Few virtual herbaria are designed with conservation use as a primary driver. Exceptionally, Brazil's Reflora Virtual Herbarium (RVH) was created to increase knowledge and conservation of the Brazilian flora. The RVH is closely integrated with the Flora of Brazil 2020 platform on which Brazil's new national Flora is under construction. Both resources are accessible via the Reflora home page and thousands of users move seamlessly between these Reflora resources. To understand how the Reflora resources are currently used and their impact on conservation science, we conducted a literature review and an online survey. We searched for publications of studies in which Reflora resources were used and publications resulting from Brazilian researchers who were part of Reflora's research and mobility program. The survey contained multiple choice questions and questions that required a written response. We targeted Reflora webpage visitors with the survey to capture a wider range of Reflora users than the literature review. Reflora resources were used for a variety of conservation-relevant purposes. Half the 806 scientific publications in which Reflora was cited and 81% of the 1069 survey respondents accessing Reflora resources mentioned conservation-relevant research outputs. Most conservation-relevant uses of the Reflora resources in scientific publications were research rather than implementation focused. The survey of Reflora users showed conservation uses and impacts of virtual herbaria were more numerous and diverse than the uses captured in the literature review. Virtual herbaria are vital resources for conservation science, but they must document use and impacts more comprehensively to ensure sustainability.     

Assessment of Water Quality in a Border Region Between the Atlantic Forest and an Urbanised Area in Rio de Janeiro,Brazil

The preservation of water resources is one of the goals of the designation of parks that act as natural reservoirs. In order to assess the impact of the presence of humans in an environmental preservation area bordering urban areas, the presence of four pathogenic enteric viruses [group A rotavirus (RV-A), norovirus (NoV), human adenoviruses (HAdV), and hepatitis A virus (HAV)], as well as the physico-chemical parameters, and Escherichia coli levels were assessed in riverine water samples. From June 2008 to May 2009, monthly monitoring was performed along the Engenho Novo River. RV-A, NoV, and HAdV were observed in 29 % (31/108) of the water samples, with concentrations of up to 10³ genome copies/liter. The natural occurrence of infectious HAdV was demonstrated by Integrated Cell Culture-PCR (ICC-PCR). This study confirms the suitability of using the detection of fecal-oral transmitted viruses as a marker of human fecal contamination in water matrices and indicates the spread of pathogenic viruses occurring in an alleged area of environmental protection.