Dioxins and furans in the atmosphere of São Paulo City, Brazil

Air samples were collected simultaneously at three urban sites in São Paulo City, Brazil, in winter, spring, summer and fall (in 2000 and 2001). Andersen PUF samplers were used for gas and particles sequential sampling. Samples were analyzed using HRGC/HRMS according to US EPA Method 8290. The greater metropolitan area of São Paulo is the largest industrialized region of Latin America and has a highly polluted atmosphere. Concentrations of dioxins and furans, which are well-known toxic chemicals, ranged from 1.14 pg m⁻³ to 13.8 pg m⁻³ (0.047 pg I-TEQ m⁻³ to 0.751 pg I-TEQ m⁻³). Principal component analysis showed that all the variables are highly correlated with one another except the 2,3,7,8-TCDD one. This is consistent with the similar concentration profiles observed for the tetra, penta, hexa, hepta and octa-homologous groups of the three sampling sites studied. At all sites, the most abundant compounds were the hepta and octa congeners. The 2,3,4,7,8-PeCDF accounted for 37–46% of the total toxicity and the 2,3,7,8-TCDD accounted for 7–16%. Highest mass concentrations of PCDD/Fs were found in the site where there is influence of industrial activities and heavy vehicular traffic fueled by gasohol, diesel, and ethanol.     

The contribution of azo dyes to the mutagenic activity of the Cristais River

To verify whether dyes emitted within the discharge of a dye processing plant were contributing to the mutagenicity repeatedly found in the Cristais River, Sao Paulo, Brazil, we chemically characterized the following mutagenic samples: the treated industrial effluent, raw and treated water, and the sludge produced by a Drinking Water Treatment Plant (DWTP) located approximately 6 km from the industrial discharge. Considering that 20% of the dyes used for coloring activities might be lost to wastewaters and knowing that several dyes have mutagenic activity, we decided to analyze the samples for the presence of dyes. Thin layer chromatographic analysis indicated the presence of three prevalent dyes in all samples, except for the drinking water. This combination of dyes corresponded to a commercial product used by the industry, and it tested positive in the Salmonella assay. The structures of the dye components were determined using proton magnetic resonance and mass spectrometric (MS) methods, and the dyes were tested for mutagenicity. The blue component was identified as the C.I. Disperse Blue 373, the violet as C.I. Disperse Violet 93, and the orange as C.I. Disperse Orange 37. The dyes showed mutagenic responses of 6300, 4600, and 280 revertants/microg for YG1041 with S9 respectively. A bioassay-directed fractionation/chemical analysis showed that the C.I. Disperse Blue 373 contributed 55% of the mutagenic activity of the DWTP sludge. We showed that these dyes contributed to the mutagenic activity found in the Cristais River environmental samples analyzed and are indirectly affecting the quality of the related drinking water. Therefore, we believe that this type of discharge should be more thoroughly characterized chemically and toxicologically. Additionally, human and ecological risks associated with the release of dye processing plant effluents should be more fully investigated, especially where the resultant water is taken for human consumption.     

Temporal changes in feeding habits and daily rations of<Emphasis Type="Italic"> Hoplostethus mediterraneus</Emphasis> in the bathyal Ionian Sea (eastern Mediterranean)

Data on the diet, feeding habits and daily rations of Hoplostethus mediterraneus Cuvier, 1829 in the bathyal eastern Ionian Sea (Mediterranean Sea) are presented. A total of 430 specimens collected by bottom trawls at depths ranging from 473 to 603 m during four 24-h day–night sampling cycles covering the four annual seasons was examined. H. mediterraneus diet consisted of pelagic and vagile epibenthic prey, mainly crustaceans, and was dominated by benthopelagic natantian decapods (83.35% IRI, index of relative importance). Seasonal changes in diet were apparent and related to seasonal fluctuations in suprabenthic and zooplanktonic prey in the environment. Diel patterns in stomach fullness and trends in diel feeding cycles are discussed in relation to the vertical migratory movements of available prey (i.e. suprabenthos and zooplankton). Daily-ration estimates were determined by evacuation-rate models and ranged from 0.143% to 0.397% WW/WW. Overall, daily-ration estimates were within the range of the daily consumption of other deep-sea fish. Deduced from diet contents, we found a constant gross energy intake (305–316 kcal g^–1) during all seasons. As a possible response to the reproductive peak of mature females observed in summer, H. mediterraneus increases its food consumption, which, in turn, is coupled with an increase in food availability.Communicated by S.A. Poulet, Roscoff     

The cellular basis of photobehavior in the tufted parenchymella larva of demosponges

The mechanisms by which light elicits a phototactic response in sponge larvae remain poorly understood. Here we investigate histological and behavioral aspects of the photoresponse in parenchymella larvae of three demosponges. Two species are photonegative during their entire larval life, while the other, initially photopositive, becomes photonegative only after swimming in the laboratory for 4 h to 6 h. All larvae are bullet-shaped, with a uniformly ciliated surface, except at their posterior end, which is unciliated but surrounded by a distinctive ring of long cilia, the tuft. The short cilia beat metachronally, generating the thrust to move the larva forward with clockwise rotation. The long cilia of the tuft do not beat metachronally and are apparently more involved in maneuvering than in the generation of thrust. Transmission electron microscopy revealed in one species that the axoneme of the short cilia contains a distinctive "9×3+2" microtubule pattern at its base, but the presence of such an arrangement in cilia of the tuft remains uncorroborated. Nevertheless, the differences in beating characteristics between the monociliated cells of the tuft and those in the rest of the body correspond to other cytological differences. Cilia of the tuft have a type-I basal body, a large basal foot, and a branched rootlet, whereas the remaining cilia have a type-II basal body, a smaller and simpler basal foot, and an unbranched rootlet. Furthermore, the cells forming the tuft have a characteristic distal protrusion filled with pigments and mitochondria. Several of these traits suggest that the monociliated cells of the tuft are involved in the larval photoresponse both as sensors and effectors. Drastic changes in light intensity have no effect on the beating of the short cilia. In contrast, they cause a predictable and instantaneous movement of each cilium in the tuft, triggering expansions and contractions of either a part or the entire tuft, which in turn alters the direction of swimming. Observations on free-swimming larvae suggest that the tuft works as a passive light-sensitive rudder in both photonegative species that contract their posterior cilia under high irradiance and in photopositive species that expand their cilia under high irradiance. However, in photonegative larvae that expand the tuft under high irradiance, an active ciliary coordination by the larva needs to be invoked to explain a deviation of the swimming trajectory.     

Multivariate analysis of the bentho-demersal ichthyofauna along soft bottoms of the Eastern Atlantic: comparison between unvegetated substrates,seagrass meadows and sandy bottoms beneath sea-cage fish farms

By means of multivariate techniques, we studied: (1) the differences in the structure of bentho-demersal, non-cryptic, fish assemblages associated with unvegetated sandy substrates, vegetated meadows constituted by the seagrass Cymodocea nodosa and the bottoms under the influence of sea-cage fish farms; as well as (2) the persistence of these patterns with regard to different scales of spatial variability, across three islands of the Canarian Archipelago (Central East Atlantic). Our sampling strategy (involving three islands, with five locations per island, and two sites within each location) detected significant changes in the composition and structure of the fish assemblages between the three habitats. Fish assemblages associated with the unvegetated and vegetated bottoms were similar among the surveyed islands. In contrast, we observed a significant inter-island variability in the fish populations associated with the sea-cage fish farms. The presence of the sea-cage fish farms increased the overall fish abundance (184.8±49.8 ind 100 m⁻²) as compared to both the vegetated (38.8±9.7 ind 100 m⁻²) and unvegetated habitats (1.1±0.4 ind 100 m⁻²). Differences within and between the habitats were found to be associated with the relative abundance of a few fish species. The most abundant species were Xyrichthys novacula in the unvegetated bottoms and Diplodus annularis, Spondyliosoma cantharus and Mullus surmuletus on the seagrass meadows. Finally, we recorded an increase in the abundance of Heteroconger longissimus, Trachinus draco and Pagellus acarne in the bottoms beneath the sea-cage fish farms. These species, in addition to a group of large benthic chondrichthyes, were responsible for the differences between islands in the composition and structure of the demersal ichthyofauna beneath the sea-cage fish farms.     

First genetic validation and diagnosis of the short-finned squid species of the genus <Emphasis Type="Italic">Illex</Emphasis> (Cephalopoda: Ommastrephidae)

Squids of the genus Illex are representative of the family Ommastrephidae and account for 65% of the world’s cephalopod captures. Illex is formed by four taxa distributed throughout the Atlantic Ocean (I. argentinus, I. coindetii, I. illecebrosus and I. oxygonius), whose identification and phylogenetic relationships based on morphological characters remain controversial. Thirty-seven enzyme-coding loci were analysed in 230 individuals from seven populations of Illex and ten specimens of Todaropsis eblanae, which were used as the outgroup. Two to four enzyme loci (ALPDH*, IDHP-1*, MEP* and SOD*) were diagnostic among Illex species depending on the species-pair comparison. Individuals morphologically identified as I. oxygonius were also found genetically distinct, which proves the taxonomic validity of this species. No significant intraspecific genetic heterogeneity was detected within Illex argentinus, I. coindetii and I. illecebrosus (Mean G _ST= 0.011, 0.003, 0.017, respectively). I. illecebrosus and I. oxygonius were shown as sister species with a close relationship to I. argentinus, whereas I. coindetii formed a different lineage.     

Genetic sub-structure and intermediate optimal outcrossing distance in the marine angiosperm <Emphasis Type="Italic">Zostera marina</Emphasis>

The spatial distribution of genetic variability depends on the spatial patterns of clonal and sexual reproduction, gene flow, genetic drift and natural selection. Species with restricted dispersal may exhibit genetic structuring within populations with immediate neighbours being close relatives, and may show differentiation among populations. Genetic structuring of a species may have important genetic, evolutionary and ecological consequences including distance-dependent mating success. In this study we used microsatellite markers to show that clones of Zostera marina in a population in the Ria Formosa, Portugal, were aggregated and covered distances of up to 3–4 m. Clones within 4 m of each other exhibited significant and positive coancestry values, reflecting the limited seed dispersal of this species. Hand-pollinations between near (0–10.9 m), intermediate (11–32 m) and far (15 km) individuals resulted in similar levels of seed set, although the near pollinations had higher, although not statistically significant, levels of seed abortion during maturation. Seeds from intermediate-distance pollinations had a significantly higher proportion of seeds germinate and shorter germination time than both the near and far seeds. Similarly, the average number of seedlings produced per pollination, used as an overall estimate of fitness, was significantly greater for the intermediate distance when compared to both near and far pollinations. These results suggest that the genetic structuring observed may result in both inbreeding and outbreeding depression, which gives rise to an intermediate optimal outcrossing distance.     

Feeding activity rhythm of<Emphasis Type="Italic"> Nephrops norvegicus</Emphasis> of the western Mediterranean shelf and slope grounds

Over a 24-h time scale, benthic decapods show complex patterns of behavioural activity associated with feeding. Information is scarce on the feeding rhythms of the burrowing decapod Nephrops norvegicus (L.), especially in those deep, benthic environments typical of western Mediterranean slopes, where the fishery of this species is highly developed. In the present study, the feeding of this species was determined by means of stomach sampling, from animals captured during four continuous 24-h cycles of trawl hauls at 100–110 m and 400–430 m, in October (the autumn equinox) and June (the spring solstice). A total of 3348 stomachs were analysed for fullness and classified by means of a visual, qualitative scale. A high proportion of the stomachs collected was empty (47.2%). Feeding rhythmicity was analysed by computing a percentage value of empty stomachs for each catch. Over 4 days, the percentage values presented marked fluctuations. Therefore, periodogram and form estimate analyses were performed on time series of percentages of empty stomachs, to determine the phase and periodicity of feeding rhythms. In October, animals ingested food during the daytime, presenting nocturnal peaks of empty stomachs at both depths considered in this study. In June, nocturnal peaks of empty stomachs were recorded for the slope, while a marked feeding arrhythmia was present on the shelf. A hypothesis linking feeding activity to endogenous rhythms in locomotion, cardiac and respiratory activities is presented to account for the animals diurnal ingestion, irrespective of the depth of distribution.Communicated by S.A. Poulet, Roscoff     

RNAi-mediated silencing of vitellogenin gene function turns honeybee (Apis mellifera) workers into extremely precocious foragers

The switch from within-hive activities to foraging behavior is a major transition in the life cycle of a honeybee (Apis mellifera) worker. A prominent regulatory role in this switch has long been attributed to juvenile hormone (JH), but recent evidence also points to the yolk precursor protein vitellogenin as a major player in behavioral development. In the present study, we injected vitellogenin double-stranded RNA (dsVg) into newly emerged worker bees of Africanized genetic origin and introduced them together with controls into observation hives to record flight behavior. RNA interference-mediated silencing of vitellogenin gene function shifted the onset of long-duration flights (>10 min) to earlier in life (by 3–4 days) when compared with sham and untreated control bees. In fact, dsVg bees were observed conducting such flights extremely precociously, when only 3 days old. Short-duration flights (<10 min), which bees usually perform for orientation and cleaning, were not affected. Additionally, we found that the JH titer in dsVg bees collected after 7 days was not significantly different from the controls. The finding that depletion of the vitellogenin titer can drive young bees to become extremely precocious foragers could imply that vitellogenin is the primary switch signal. At this young age, downregulation of vitellogenin gene activity apparently had little effect on the JH titer. As this unexpected finding stands in contrast with previous results on the vitellogenin/JH interaction at a later age, when bees normally become foragers, we propose a three-step sequence in the constellation of physiological parameters underlying behavioral development. David Santos Marco Antonio and Karina Rosa Guidugli-Lazzarini contributed equally to the present study.     

Availability of ammonium influences photosynthesis and the accumulation of mycosporine-like amino acids in two<Emphasis Type="Italic"> Porphyra</Emphasis> species (Bangiales,Rhodophyta)

The effect of ammonium concentration on photosynthetic activity estimated as in vivo chlorophyll fluorescence, i.e. maximal quantum yield (F_v/F_m) and electron transport rate (ETR) and on the accumulation of mycosporine-like amino acids (MAAs), chlorophyll a (chl a), biliproteins (BP) and soluble proteins (SP) in the red algae Porphyra leucosticta Thuret in Le Jolis collected from Lagos (Málaga, Spain) and Porphyra umbilicalis (Linnaeus) J. Agardh from Helgoland (Germany) was evaluated. Discs of both species were incubated with three ammonium concentrations (0, 100 and 300 µM) under artificial PAR and UV radiation for 7 days. Photosynthetic activity decreased under the culture conditions due to UV radiation and ammonium availability. The decrease of both F_v/F_m and maximal ETR was related to ammonium supply, i.e. the lowest decrease occurred in algae growing with the highest concentration of ammonium. In both species, after 7 days of culture, the content of chl a, BP and SP was higher under 300 µM than that under 0 and 100 µM ammonium. In both species, the content of MAAs was increased under 300 µM ammonium compared to the initial value, whereas a decrease under 0 and 100 µM ammonium was observed only in P. leucosticta. The content of MAAs in P. umbilicalis did not present significant differences compared to the initial value, probably because of the high initial content of MAAs. In both Porphyra species, four MAAs were identified: shinorine, porphyra-334, palythine and asterina-330. However, P. leucosticta modified its MAA pattern during the incubation time, reaching the same percentages found for P. umbilicalis, which did not show any change during the experimental period. P. leucosticta exhibited a decrease in BP/SP and BP/chl a ratios through the incubation time and an increase in MAAs/BP. The ratio MAAs/chl a did not show any variation with time or treatment, as was also true for all ratios in P. umbilicalis. In summary, ammonium supply diminished the decrease of F_v/F_m, increased the content of photosynthetic pigments (chlorophyll and biliprotein) and soluble protein, and stimulated of the accumulation of MAAs in the red algae P. leucosticta and P. umbilicalis.Communicated by O. Kinne, Oldendorf/Luhe