This study was conducted to evaluate the microbiological quality of a mangrove estuary in the Vitória Bay region, Espírito Santo, Brazil. We analyzed the presence and concentration of enteric viruses and thermotolerant coliforms in water, mussels (Mytella charruana and Mytella guyanensis), and oysters (Crassostrea rhizophorae), collected over a 13-month period. Human adenovirus, rotavirus A (RVA), and norovirus genogroup II were analyzed by quantitative PCR. The highest viral load was found in RVA-positive samples with a concentration of 3.0 × 104 genome copies (GC) L−1 in water samples and 1.3 × 105 GC g−1 in bivalves. RVA was the most prevalent virus in all matrices. Thermotolerant coliforms were quantified as colony-forming units (CFU) by the membrane filtration method. The concentration of these bacteria in water was in accordance with the Brazilian standard for recreational waters (< 250 CFU 100 mL−1) during most of the monitoring period (12 out of 13 months). However, thermotolerant coliform concentrations of 3.0, 3.1, and 2.6 log CFU 100 g−1 were detected in M. charruana, M. guyanensis, and C. rhizophorae, respectively. The presence of human-specific viruses in water and bivalves reflects the strong anthropogenic impact on the mangrove and serves as an early warning of waterborne and foodborne disease outbreaks resulting from the consumption of shellfish and the practice of water recreational activities in the region.
In populations of various ant species, many queens reproduce in the same nest (polygyny), and colony boundaries appear to
be absent with individuals able to move freely between nests (unicoloniality). Such societies depart strongly from a simple
family structure and pose a potential challenge to kin selection theory, because high queen number coupled with unrestricted
gene flow among nests should result in levels of relatedness among nestmates close to zero. This study investigated the breeding
system and genetic structure of a highly polygynous and largely unicolonial population of the wood ant Formica paralugubris. A microsatellite analysis revealed that nestmate workers, reproductive queens and reproductive males (the queens' mates)
are all equally related to each other, with relatedness estimates centring around 0.14. This suggests that most of the queens
and males reproducing in the study population had mated within or close to their natal nest, and that the queens did not disperse
far after mating. We developed a theoretical model to investigate how the breeding system affects the relatedness structure
of polygynous colonies. By combining the model and our empirical data, it was estimated that about 99.8% of the reproducing
queens and males originated from within the nest, or from a nearby nest. This high rate of local mating and the rarity of
long-distance dispersal maintain significant relatedness among nestmates, and contrast with the common view that unicoloniality
is coupled with unrestricted gene flow among nests.
Received: 8 February 1999 / Received in revised form: 15 June 1999 / Accepted: 19 June 1999 相似文献
Summary Inbreeding may have important consequences for the genetic structure of social insects and thus for sex ratios and the evolution of sociality and multiple queen (polygynous) colonies. The influence of kinship on mating preferences was investigated in a polygynous ant species, Iridomyrmex humilis, which has within-nest mating. When females were presented simultaneously with a brother that had been reared in the same colony until the pupal stage and an unrelated male produced in another colony, females mated preferentially with the unrelated male. The role of environmental colony-derived cues was tested in a second experiment where females were presented with two unrelated males, one of which had been reared in the same colony until the pupal stage (i.e., as in the previous experiment), while the other had been produced in another colony. In this experiment there was no preferential mating with familiar or unfamiliar males, suggesting that colony-derived cues might not be important in mating preferences. Inbreeding was shown to have no strong effect on the reproductive output of queens as measured by the number of worker and sexual pupae produced. The level of fluctuating asymmetry of workers produced by inbreeding queens was not significantly higher than that of non-inbreeding queens. Finally, colonies headed by inbreeding queens did not produce adult diploid males. Based on the current hypotheses of sex-determination the most plausible explanations for the absence of diploid-male-producing colonies are that (i) workers recognized and eliminated these males early in their development, and/or (ii) there are multiple sex-determining loci in this species. It is suggested that even if inbreeding effects on colony productivity are absent or low, incest avoidance mechanisms may have evolved and been maintained if inbreeding queens produce a higher proportion of unviable offspring.
Correspondence to: L. Keller at the present address 相似文献
A soil profile from 0 to 90 cm was collected in an undisturbeded area of Cape Cod, Massachusetts. Five centimeter increments of the profile were analyzed for 234,238U, 226Ra, 210Pb and 210Po. The factors affecting the activity distribution of these naturally-occurring radionuclides are discussed for this particular soil type. 相似文献
Seasonal growth was studied in potted cuttings of hybrid poplar (one clone of Populus x euramericana) either exposed to ozone in filtered air (0 = control, 0.05, 0.10 microl litre(-1)) or in ambient air (mean = 0.03 microl litre(-1)). Only at 0.10 microl litre(-1) was biomass production reduced and related to leaf loss rather than leaf formation, since the latter was similar in all treatments. Stem length at 0.10 microl litre(-1) approached that of the control, whereas starch concentration in the green stem bark tended to be reduced, as were the ratios of stem weight/length and root/shoot biomass. The changes in carbon allocation and biomass production gradually became established during the second half of the growing season. At the altered carbon allocation at 0.10 microl litre(-1), the ratio of whole-plant production/attached foliage area resembled that of the other O(3) regimes. However, the latter ratio was strongly reduced at 0.10 microl litre(-1) when calculated on the basis of the potential foliage area, as compensated for the O(3)-induced leaf loss. Thus the carbon return/cost balance of the totally formed foliage was low, although the relative-growth rate of ozonated plants temporarily reached that of the control. The relation between leaf differentiation under ozonation (lowered stomatal density) and whole-plant production remains uncertain. The plant behavior found is discussed in terms of passive response or acclimatization to O(3) stress. 相似文献