Population structure and genetic diversity in green turtles nesting at Tortuguero,Costa Rica,based on mitochondrial DNA control region sequences

The green turtle (Chelonia mydas) nesting population at Tortuguero, Costa Rica, is the largest nesting aggregation in the Atlantic, by at least an order of magnitude. Previous mitochondrial DNA (mtDNA) surveys based on limited sampling (n = 41) indicated low genetic diversity and low gene flow with other Caribbean nesting colonies. Furthermore, a survey of nuclear DNA diversity invoked the possibility of substructure within the Tortuguero rookery. To evaluate these characteristics, mtDNA control region sequences were determined for green turtles nesting at Tortuguero in 2001 (n = 157) and 2002 (n = 235). The increased sample revealed three additional haplotypes; five haplotypes are now known for Tortuguero female green turtles. Analyses of molecular variance indicated that there was no significant spatial population structure along the 30-km nesting beach. In addition, no temporal population structure was detected either between the two nesting seasons or within the nesting season. As a result of the larger sample size and additional haplotypes, estimates of genetic separation among Caribbean nesting colonies have changed and the concordance of phylogenetic and phylogeographic patterns reported in the past for green turtles in the Greater Caribbean has weakened. The five haplotypes from Tortuguero represent 36% of the haplotypes identified in green turtle nesting aggregations in the Greater Caribbean and 17% of the haplotypes known to occur in nesting or foraging aggregations in the Greater Caribbean. Haplotype diversity (0.16) and nucleotide diversity (0.0034) for the Tortuguero population are substantially lower than those for the combined rookeries in the Greater Caribbean (0.44 and 0.0078, respectively). Although comprehensive evaluation of regional genetic diversity requires nuclear DNA data, our study indicates that conserving genetic diversity in Caribbean green turtles will require careful management of the smaller rookeries in addition to the Tortuguero rookery.     

Antimicrobial activities of extracts from tropical Atlantic marine plants against marine pathogens and saprophytes

Studies investigating disease resistance in marine plants have indicated that secondary metabolites may have important defensive functions against harmful marine microorganisms. The goal of this study was to systematically screen extracts from marine plants for antimicrobial effects against marine pathogens and saprophytes. Lipophilic and hydrophilic extracts from species of 49 marine algae and 3 seagrasses collected in the tropical Atlantic were screened for antimicrobial activity against five ecologically relevant marine microorganisms from three separate kingdoms. These assay microbes consisted of the pathogenic fungus Lindra thalassiae, the saprophytic fungus Dendryphiella salina, the saprophytic stramenopiles, Halophytophthora spinosa and Schizochytrium aggregatum, and the pathogenic bacterium Pseudoaltermonas bacteriolytica. Overall, 90% of all species surveyed yielded extracts that were active against one or more, and 77% yielded extracts that were active against two or more assay microorganisms. Broad-spectrum activity against three or four assay microorganisms was observed in the extracts from 48 and 27% of all species, respectively. The green algae Halimeda copiosa and Penicillus capitatus (Chlorophyta) were the only species to yield extracts active against all assay microorganisms. Among all assay microorganisms, both fungi were the most resistant to the extracts tested, with less than 21% of all extracts inhibiting the growth of either L. thalassiae or D. salina. In contrast, over half of all lipophylic extracts were active against the stramenopiles H. spinosa and S. aggregatum, and the bacterium P. bacteriolytica. Growth sensitivity to hydrophilic extracts varied considerably between individual assay microorganisms. While 48% of all hydrophilic extracts were active against H. spinosa, 27% were active against P. bacteriolytica, and only 14% were active against S. aggregatum. Overall, more lipophilic extracts inhibited microbial growth than hydrophilic extracts. The variability observed in the antimicrobial effects of individual extracts against each assay microorganism reflects the importance of choosing appropriate test microbes in assays from which ecologically relevant information is sought. Results from this survey demonstrate that antimicrobial activities are prevalent among extracts from marine algae and seagrasses, suggesting that antimicrobial chemical defenses are widespread among marine plants.     

Uptake and metabolism of 2,4,6-trinitrotoluene in higher plants

The fate of the explosive 2,4,6-TNT in plants is of major interest. Therefore, a method was developed to analyse TNT and derivatives in plant tissue. The method was utilized to investigate the uptake and metabolism of TNT inMedicago sativa andAllium schoenoprasum grown in hydroponic cultures containing TNT levels of 0.1 to 10 mg/1. Detectable concentrations of nitrotoluenes were significantly higher inAllium schoenoprasum than inMedicago sativa. The uptake of TNT in plants was directly related to the initial TNT level. The principal nitroaromatic components in roots and shoots of both plant species were identified as 4-ADNT and 2-ADNT in equal amounts, with substantially less TNT.     

The SeKT joint research project: definition of reference conditions, control sediments and toxicity thresholds for limnic sediment contact tests

- In current biotest approaches, intact organisms or in vitro systems are exposed to sediments using different exposure scenarios. The most important issue in sediment toxicity testing protocols is the question which test phase (solid or liquid) should be used. Whole-sediment exposure protocols represent the most realistic scenario to simulate in situ exposure conditions in the laboratory. However, until now there is no agreement in how to acquire and to evaluate the data of the various available sediment contact assays. The SeKT joint research project was initiated with the aim to compare recently developed sediment contact assays by addressing reference conditions, control sediments and toxicity thresholds for limnic sediment contact tests.     

Stra?enversiegelung in Deutschland und ihre Beinflussung der Umwelt im Vergleich mit anderen OECD-L?ndern

Zusammenfassung  Die durch die Fernstra?en versiegelte Fl?che in Deutschland betr?gt 0,47% der Oberfl?che, ohne die Seitenstreifen und Gemeindestra?en. Z?hlt man diese hinzu, so erh?ht sich der Wert auf 1,3%. In den dicht besiedelten Bundesl?ndern Hessen und Nordrhein-Westfalen erh?hen sich die Werte in Hessen auf 0,59 bzw. 1,59% und in NRW auf 0,68 bzw. 1,82%. In anderen OECD-L?ndern betragen die Prozents?tze des durch Fernstra?en versiegelten Bodens zwischen 0,2 und 3,0%. Bei diesem Vergleich liegt Deutschland an 5. Stelle hinter den Benelux-L?ndern und Japan. In der Verkehrsdichte (zugelassene Kraftfahrzeuge pro Stra?enkilometer) liegt Deutschland an 3. Stelle hinter Italien und Gro?britannien. Die Bodenversiegelung durch Stra?endecken sch?digt die Umwelt durch die Einbringung verkehrsbedingter Schadstoffe und St?rung des Grundwasserspiegels, aber noch mehr durch die Zerteilung und Zerst?rung von Biotopen. Online-First: 19. Mai 2000     

A salamander’s toxic arsenal: review of skin poison diversity and function in true salamanders,genus <Emphasis Type="Italic">Salamandra</Emphasis>

Terrestrial salamanders of the genus Salamandra represent one of the most prominent groups of amphibians. They are mainly distributed across Europe but also reach Northern Africa and the Near East. Members of the six currently accepted species have long been known to be poisonous; however, work on their toxins was mostly published in German language, and therefore, many nuances of these studies have remained hidden from the majority of herpetologists and toxinologists. Several Salamandra species are called fire salamanders due to their highly contrasted, black-yellow colouration which probably serves to deter predators, although thorough evidence for aposematism in Salamandra is still lacking. Salamandra skin toxins do not only represent a potent antipredator defence but may also have antimicrobial effects. A better understanding of this dual function of Salamandra skin secretions is of utmost importance in the face of the emergence of a fungal disease causing catastrophic declines of fire salamanders in Central Europe, caused by the fungus Batrachochytrium salamandrivorans. In this review, we summarize the knowledge on Salamandra toxins, providing a list of the compounds so far isolated from their secretion and focusing on the bioactivity of the major compounds in Salamandra secretions, the steroidal alkaloids. We identify priorities for future research, including a screening of co-occurrence of steroidal alkaloids and tetrodotoxins in salamandrids, chemical characterization of already identified novel steroidal compounds, elucidation of the presence and role of peptides and proteins in the secretion, and experimental in vitro and in vivo study of the interactions between bioactive compounds in Salamandra skin secretions and cutaneous fungal and bacterial pathogens.     

Verteilung und Abnahme von bodennahem Ozon in städtischen und ländlichen Regionen

The compilation of ozone data for the federal states of Hesse and Northrhine-Westphalia (NRW) in Germany indicated that the concentration of ozone level slightly decreased during the years 1990–1998. The average concentration of ozone over forest areas is significantly higher than over cities. Only the maximum figures in the years approached one another. However, values passing the legal thresholds (180 μg ozone/m³) were two to three-fold higher over forests than over cities. The ozone concentration in air is inversely proportional to the traffic density. It is suggested that the lower NOx concentration over the forest than over cities is involved in the maintenance of the higher ozone-concentration over forest areas. In the cities, the ozone is reduced by NO to almost zero at night, whereas it is reduced by only about 50% over forests with lower NO concentrations. This reduction is only partially compensated in connection with the photolysis of NO₂ and the subsequent oxidation of O₂ to O₃ during the day. The ozone situation is principally the same in the federal states of Hesse and Northrhine-Westphalia.     

Predictors of food-related aggression in wild Assamese macaques and the role of conflict avoidance

The quality, availability and distribution of food resources and their influence on types and levels of feeding competition play a central role in ecological models of female social structure in mammals. Here, we investigate the impact of social and ecological factors on rates of food-related aggression and the use of potential conflict avoidance mechanisms in wild Assamese macaques (Macaca assamensis) in northeastern Thailand. These questions were addressed by examining feeding competition at the level of individual food patches which provides detailed information on resource characteristics, aggression and feeding party composition. Results suggest that the frequency of aggression in food patches increases with increasing feeding group size and decreasing patch size but is not affected by ecological variables representing resource value (abundance and nutritional value of food items in a patch). Interestingly, females appear to employ several mechanisms to avoid direct conflicts, including the use of alternative feeding sites within food patches, delayed arrival at feeding sites, storing food in cheek pouches and co-feeding with individuals they share strong social bonds with. Conflict avoidance may be partially responsible for the absence of a rank-related skew in female energy intake in this population and may explain other cases where empirical data do not fit the predictions of socio-ecological theory. Our findings also inform the debate about the mechanisms generating fitness benefits from strong social bonds by suggesting that by increasing feeding tolerance, social bonds may enhance resource acquisition, reduce the risk of injuries and lower levels of agonism-related stress.     

Is male rhesus macaque red color ornamentation attractive to females?

Male sexually selected traits can evolve through different mechanisms: conspicuous and colorful ornaments usually evolve through intersexual selection, while weapons usually evolve through intra-sexual selection. Male ornaments are rare among mammals in comparison to birds, leading to the notion that female mate choice generally plays little role in trait evolution in this taxon. Supporting this view, when ornaments are present in mammals, they typically indicate social status and are products of male-male competition. This general mammalian pattern, however, may not apply to rhesus macaques (Macaca mulatta). Males of this species display conspicuous skin coloration, but this expression is not correlated to dominance rank and is therefore unlikely to have evolved due to male-male competition. Here, we investigate whether male color expression influences female proceptivity toward males in the Cayo Santiago free-ranging rhesus macaque population. We collected face images of 24 adult males varying in dominance rank and age at the peak of the mating season and modeled these to rhesus macaque visual perception. We also recorded female sociosexual behaviors toward these males. Results show that dark red males received more sexual solicitations, by more females, than pale pink ones. Together with previous results, our study suggests that male color ornaments are more likely to be a product of inter- rather than intra-sexual selection. This may especially be the case in rhesus macaques due to the particular characteristics of male-male competition in this species.