Sperm production in an extremophile fish,the cave molly (<Emphasis Type="Italic">Poecilia mexicana</Emphasis>, Poeciliidae,Teleostei)

A prominent trade-off in life history theory and evolution balances the costs of reproduction with those of basic somatic needs. Hence, reproductive efforts may be reduced in environments where additional energy is required for somatic maintenance. Here, we investigated male sperm stores in Atlantic mollies (Poecilia mexicana) from a sulfidic cave and several sulfidic and non-sulfidic surface habitats. We found significant differences among populations in the number of sperm stripped per male, which was also correlated with differences in gonad weights. The largest sperm stores were detected in males from non-sulfidic surface creeks, while males from a partially sulfidic surface system had lower sperm counts, and males from completely sulfidic systems, surface as well as subterranean, had even fewer available sperm. We conclude that the extreme environmental conditions in sulfidic habitats appear to constrain male sperm production, since hydrogen sulfide as a naturally occurring toxin requires energy-demanding adaptations. Furthermore, we examined sperm counts of lab-reared cave and surface mollies in response to energy limitation. Males from stock populations were placed under high and low food treatments for a 2-week period and then stripped of sperm. Sperm counts of surface mollies tended to be reduced by low food availability, whereas sperm counts of cave mollies did not significantly vary between food treatments, which likely points towards a higher starvation resistance in cave mollies.     

Molecular phylogeny of songbirds (Aves: Passeriformes) and the relative utility of common nuclear marker loci

While the monophyly of the largest avian order Passeriformes as well as its suborders suboscines (Tyranni) and oscines (Passeri) is well established, lower phylogenetic relationships of this fast radiated taxon have been a continuous matter of debate, especially within the suborder oscines. Many studies analyzing phylogenetic relationships of the Passeriformes using molecular markers have been published, which led to a better resolved phylogeny. Conflicting hypotheses and still remaining uncertainties, especially within the Passerida, have repeatedly stimulated further research with additional new markers. In the present study we used a combination of established molecular markers (RAG‐1, RAG‐2, c‐myc) and the recently introduced ZENK. We accomplished phylogenetic analyses using maximum parsimony, maximum likelihood and Bayesian inference, both separately for all genes and simultaneously. To assess the phylogenetic utility of the different genes in avian systematics we analyzed the influence of each data partition on the phylogenetic tree yielded by the combined approach using partitioned Bremer support. Compared with the other single gene analyses, the ZENK trees exhibited by far the best resolution and showed the lowest amount of homoplasy. Our data indicate that this gene is—at least in passerines—suitable for inference of even old taxonomic splits. Our combined analysis yields well‐supported phylogenetic hypotheses for passerine phylogeny and apart from corroborating recently proposed hypotheses on phylogenetic relationships in the Passeriformes we provide evidence for some new hypotheses. The subdivision of the Passerida into three superfamilies, Sylvioidea, Passeroidea and Muscicapoidea, the first as sister to the two latter groups is strongly supported. We found evidence for a split between Paridae and the remaining Sylvioidea. © The Willi Hennig Society 2007.     

Molecular detection and differentiation of Brazilian and African isolates of the entomopathogen Neozygites tanajoae (Entomophthorales: Neozygitaceae) with PCR using specific primers

Neozygites tanajoae is an entomopathogenic fungus which has been used for biocontrol of the cassava green mite (Mononychellus tanajoa, CGM) in Africa. Establishment and dispersal of Brazilian isolates which have been introduced into some African countries in recent years to improve CGM control was followed with specific PCR assays. Two primer pairs, NEOSSU_F/NEOSSU_R and 8DDC_F/8DDC_R, were used to differentiate isolates collected from several locations in Brazil and from three countries in Africa, Benin, Ghana and Tanzania. The first primer pair enabled the species-specific detection of Neozygites tanajoae, while the second differentiated the Brazilian isolates from those of other geographical origin. PCR assays were designed for detection of fungal DNA in the matrix of dead infested mites since N. tanajoae is difficult to isolate and culture on selective artificial media. Our results show that all isolates (Brazilian and African) that sporulated on mummified mites were amplified with the first primer pair confirming their Neozygites tanajoae identity. The second pair amplified DNA from all the Brazilian isolates, but did not amplify any DNA samples from the African isolates. None of the two primers showed amplification neither from any of the non-sporulating mite extracts nor from the dead uninfected mites used as negative controls. We confirmed that the two primer pairs tested are suitable for the detection and differential identification of N. tanajoae isolates from Brazil and Africa and that they are useful to monitor the establishment and spread of the Brazilian isolates of N. tanajoae introduced into Benin or into other African countries for improvement of CGM biocontrol.     

Hormone-regulated expression and distribution of versican in mouse uterine tissues

Background  

Remodeling of the extracellular matrix is one of the most striking features observed in the uterus during the estrous cycle and after hormone replacement. Versican (VER) is a hyaluronan-binding proteoglycan that undergoes RNA alternative splicing, generating four distinct isoforms. This study analyzed the synthesis and distribution of VER in mouse uterine tissues during the estrous cycle, in ovariectomized (OVX) animals and after 17beta-estradiol (E2) and medroxyprogesterone (MPA) treatments, either alone or in combination.     

Genetic structure reveals management units for the yellow cardinal (<Emphasis Type="Italic">Gubernatrix cristata</Emphasis>), endangered by habitat loss and illegal trapping

The yellow cardinal, Gubernatrix cristata, is an endangered passerine from southern South America. Populations are declining due to the loss of their natural habitat, which has caused a fragmented distribution, and the continuous extraction of individuals from the wild, mainly males, to sell them as cage birds. In this study, we assess the genetic variability of remaining yellow cardinal’s populations and determine whether these populations represent independent management units. We found that the degree of geographic isolation of the remaining populations parallels the genetic differentiation of these populations for both mitochondrial and nuclear markers, and supports the delimitation of four management units for the yellow cardinal (three in Argentina and one in Uruguay). Assignment tests showed that geographic genetic differentiation can be used to assign seized individuals from illegal pet trade to their original populations and thus manage their release.     

Potential effects of global warming on oilseed rape pathogens in Northern Germany

This review analyses potential effects of global warming, i.e. higher mean temperatures, on the life cycle of five economically important oilseed rape pathogens in Northern Germany using a meta-analytical approach. First, the currently available but strongly fragmented knowledge about temperature influences on individual life cycle stages of the referred pathogens, such as survival, sporulation, infection and disease progress is summarised. These data are compared with current regional climate projections (REMO model) based on emission scenario A1B for the periods 2001–2030 and 2071–2100 in three different oilseed rape growing regions in Lower Saxony, Germany, using a baseline historical series of meteorological data collected from 1971 to 2000. Our analysis suggests that warming might lead to shifts in the future prevalence of these pathogens. Verticillium longisporum, Sclerotinia sclerotiorum and Alternaria brassicae could be particularly favoured, but beneficial effects may also occur for certain life cycle stages of Phoma lingam, such as infection and stem canker development. Pyrenopeziza brassicae might even lose importance under future warming. These changes may be particularly explicit in the long-term view (2071–2100). However, predictions on potential disease shifts are restricted by a lack of reliable, high-resolution future climate scenarios and complicated by the prospective adaptations of farming techniques and crop genotypes to climate change.     

Ornithologische Beobachtungen aus dem Hornsund-Gebiet auf West-Spitzbergen

Ohne ZusammenfassungErgebnisse der Deutschen Spitzbergen-Expeditionen von Dr.Herbert Rieche 1937 und 1938.Zugleich 204. Ringfundmitteilung der Vogelwarte Helgoland.