Virus Genome Quantification Does not Predict Norovirus Infectivity After Application of Food Inactivation Processing Technologies

When determining the effect of food processing on the infectivity of any contaminating virus, it is necessary to distinguish unambiguously between infectious and non-infectious viruses present. However, this can be difficult in the particular case of noroviruses (NoVs) because no reliable cell culture model is available. The aim of this study was to assess the use of molecular methods—RT real-time PCR (RT-qPCR) and enzymatic treatment (ET) coupled to RT-qPCR—to quantify the infectivity of NoV after application of various inactivating food-processing technologies. RT-qPCR and ET-RT-qPCR gave significantly different (P < 0.01) results concerning the reduction in viral genome counts by all inactivation procedures and conditions used, except for HHP treatment at 600 MPa for 5 min. These findings indicate that the ET prior to RT-qPCR has an effect on the estimation of the reduction of virus genome counts, and may eliminate genomes of affected virus particles. However, no correlation was found between the results obtained by ET-RT-qPCR and those obtained by cell culture. Therefore, the effect is presumably only partial, and not adequate to allow accurate estimation of virus inactivation. Consequently, our results indicate that the quantification of virus genomes by PCR, regardless of prior ET, is not adequate for establishing virus inactivation and/or infectivity. In addition, our results also illustrate that the general effect of virus inactivation is not directly correlated to effects on the integrity of virus genome and protein capsid. Presumably, inactivation by food processing is the consequence of effects on proteins involved in adhesion and invasion stages.     

The kinetics of reductive dehalogenation of a set of halogenated aliphatic hydrocarbons in anaerobic sediment slurries

Disappearance rate constants are reported for the reductive transformation of 17 halogenated aliphatic hydrocarbons in anaerobic sediment-water samples. Statistical experimental design in combination with multivariate chemical characterization of their chemical properties was used to select the compounds. Degradation followed pseudo first-order kinetics through at least two half-lives for 15 of the 17 compounds. Of all the compounds investigated, 1,2,3-trichloropropane and dichloromethane were unique in that they were dehalogenated according to zero-order kinetics. Reductive dehalogenation was the sole transformation reaction taking place.     

Antiestrogenic activity of anthropogenic and natural chemicals

A number of natural and man-made chemicals possess antiestrogenic activity, i.e. they antagonize a broad spectrum of estrogen-induced responses in vertebrates. Examples of antiestrogens include dioxin, furan and PCB congeners, certain PAHs, pesticides and indol-3-carbinol derivatives. Major mechanisms of antiestrogenicity are antagonistic action of chemicals at the estrogen receptor, or binding of chemicals to the arylhydrocarbon (Ah) receptor and subsequent interaction with estrogen-responsive genes. Toxicological consequences resulting from antiestrogenic activity have not been conclusively demonstrated to date, although antiestrogenic compounds could critically affect sensitive reproductive and developmental processes.     

Monitoring of the Phytosanitary State of Navarra's Forests, Spain

Between 1988 and 1993 six surveys on the condition of forests in Navarra (North Spain) were carried out. The results, relating to 408 trees in 17 sampling points, showed that the overall percentage of damaged trees increased from 2.86% in 1988 to 18.6% in 1993, which indicates a general large-scale deterioration of forest condition. Among the most common groups of trees, the most severely affected species were Quercus faginea, Quercus robur and Pinus sylvestris. Furthermore, it was observed that defoliation and discoloration processes did not occur randomly between stand trees, but the trees that were damaged one year (1992) were more predisposed to suffer damage in the next year (1993).     

Diel Variability of Water Quality in a Tropical Polluted Bay

The objective is to describe and quantify the diel variability of water quality in a tropical coastal system, Guanabara Bay, Brazil. Water samples were collected in spring and neap tide cycles over 24 h periods at three strategic sites. A pollution gradient was evident between the sampling sites. The average fecal coliform values decreased from 10⁶ (site 3, most polluted) to 10¹ (site 1, less polluted). Organic matter mineralization was found in a similar gradient to organic pollution. However, complete nitrification was only found associated to regions where the water quality was better. Variability in this data set was determined mostly by the pollution gradient observed, and by tidal influence as well. The poor water quality indicates that the bay undergoes severe environmental stress. However water renewal promoted by tidal action was an important mechanism in diluting the pollution, improving water quality even in ebb tides and in the inner channels. The significance of micro-scale changes in water quality assessment in Guanabara Bay was confirmed, as well as the importance of these strategic sampling sites, reinforcing the importance of these measurements in monitoring programs.     

Composition of extractable organic matter in aerosols from urban areas of Rio de Janeiro city, Brazil

The hydrocarbon compositions of atmospheric particulate matter from urban areas of Rio de Janeiro city have been studied to assess the different pollution levels. Samples were acquired using a standard high-volume air sampler (Hi-Vol), extracts were prepared and fractionated into aliphatic and aromatic compounds. High-resolution gas chromatography and GC coupled to mass spectrometry (GC–MS) were used for the analysis of the organic matter. The results show that all samples contain n-alkanes, but the distributions are different for each sample, reflecting both the biogenic (vascular plant wax input) and fossil fuel contamination sources (vehicular exhaust). The fossil fuel biomarkers, hopanes and steranes, were also observed in all samples except in the Tijuca Forest, which is a mountain forest in the midst of the sea-level city. A decrease in the level of pollution was observed in the sequence for Rebouças Tunnel>Cinelândia (downtown)>Quinta da Boa Vista Park>Tijuca Forest, as expected from the traffic density. Unfortunately, all sites are polluted mainly from vehicular emissions, but at different degrees, with the lowest levels in Tijuca Forest.     

Integrated coastal management: the challenge of transdisciplinarity

The Euroconference on Coastal Management Research held in San-Feliu de Guixols, Spain, in December 1997 brought together scientists from a great variety of disciplines in the natural and social sciences, in a search for modes of transdisciplinary cooperation in the context of integrated coastal management. During the conference the participants discussed which interactions among disciplines are required for different coastal issues. Discussion groups each focused on a particular type of coastal environment, characterized by a particular type and degree of development. The group discussions were inspired by background papers which were prepared for this purpose by invited speakers. A selection of these background papers were redrafted on the basis of the conference outcome, and are published in this issue of theJournal of Coastal Conservation. The reports of the discussion groups are published in a conference proceedings booklet issued by EMAPS (1998), the European Polar and Marine Sciences Secretariat. A synthesis of ideas on the challenge of transdisciplinarity, expressed during the discussion group sessions, is presented in this introduction. The statements reflect opinions or suggestions which received broad support from the participants; they should not be taken as proven knowledge.     

Effects of paternal care on reproductive success in the polygynous spotless starling Sturnus unicolor

For males of socially polygynous avian species like the spotless starling, there may exist a trade-off between investing in paternal care and controlling several nests. To determine how the intensity of paternal care affects reproductive success per brood sired or expressed as the total number of young raised in all nests controlled by the same male, it is necessary to manipulate paternal care. Testosterone (T) has been shown to depress the tendency for males to care for their young, and induces them to acquire more mates. The effects of paternal care on reproductive success were studied by treating certain male starlings with exogenous T and others with the antiandrogen cyproterone acetate (CA), and comparing the parental behavior of T- and CA-males throughout the breeding season with that of controls. CA-males fed their chicks more during the first week after hatching than T-males, with controls feeding at intermediate rates, both on a per nest basis and as total effort for all nests controlled by the same male. Paternal feeding rates during the first week of chick life had a significant positive effect on the number of fledged young. The hormone treatment significantly affected the number of chicks raised per nest, CA-males having a higher breeding success per nest than T-males, and controls showing intermediate levels of success. There was no significant effect of treatment on total reproductive success attained by males throughout the season. In the polygonous spotless starling, the intensity of paternal care of young affects reproductive success per nest positively but not on a seasonal basis. Received: 6 February 1999 / Received in revised form: 30 June 1999 / Accepted: 11 July 1999     

Effects of sex-associated competitive asymmetries on foraging group structure and despotic distribution in Andean condors

Phenotype-limited interference models assume competitive asymmetries among conspecifics and unequal sharing of resources. Their main prediction is a correlation between dominance status and patch quality: dominant individuals should preferentially exploit better-quality habitats. We tested assumptions and predictions of the phenotype-limited interference model in Andean condors (Vultur gryphus), a New World vulture with strong sexual size dimorphism (males are 30–40% heavier than females). We recorded searching birds in habitats differing in quality: mountains and plains. We also observed scavenging behaviour at 20 sheep carcasses, and videotaped 5 of them. Intraspecific hierarchy at carcasses was based on size: males dominated females and, within each sex, older birds dominated younger ones. Adult males and juvenile females occupied extreme positions in the feeding hierarchy. Aggression was directed at those individuals belonging to lower hierarchical levels. In high-quality areas (mountains), more condors arrived at carcasses. Juvenile females were more often observed searching in low-quality areas (plains), far from breeding areas and main roost sites. GLM analyses of individual behaviour showed that the hierarchy did not influence time of arrival, but low-ranking individuals spent more time at carcasses, especially if the number of condors at arrival was high. Additionally, low-ranking condors spent less time feeding at carcasses when individuals of higher hierarchical levels were present. On the other hand, the number of condors present had a positive effect on feeding rates of dominant individuals, probably because of a reduction in individual vigilance. These results support most of the assumptions and predictions of the phenotype-limited distribution model, although a spatial truncated distribution between phenotypes was not observed. Asymmetric feeding pay-off, unequal parental roles and sexual selection constraints could favour sexual divergence in body size in Andean condors. Received: 6 April 1998 / Accepted after revision: 11 July 1998