Parentage-based pedigree reconstruction reveals female matrilineal clusters and male-biased dispersal in nongregarious Asian great apes, the Bornean orang-utans (Pongo pygmaeus)

Philopatry and sex-biased dispersal have a strong influence on population genetic structure, so the study of species dispersal patterns and evolutionary mechanisms shaping them are of great interest. Particularly nongregarious mammalian species present an underexplored field of study: despite their lower levels of sociality compared to group-living species, interactions among individuals do occur, providing opportunities for cryptic kin selection. Among the least gregarious primates are orang-utans (genus: Pongo), in which preferential associations among females have nevertheless been observed, but for which the presence of kin structures was so far unresolved because of the equivocal results of previous genetic studies. To clarify relatedness and dispersal patterns in orang-utans, we examined the largest longitudinal set of individuals with combined genetic, spatial and behavioural data. We found that males had significantly higher mitochondrial DNA (mtDNA) variation and more unique haplotypes, thus underscoring their different maternal ancestries compared to females. Moreover, pedigree reconstruction based on 24 highly polymorphic microsatellite markers and mtDNA haplotypes demonstrated the presence of three matrilineal clusters of generally highly related females with substantially overlapping ranges. In orang-utans and possibly other nongregarious species, comparing average biparental relatedness (r) of males and females to infer sex-biased dispersal is extremely problematic. This is because the opportunistic sampling regime frequently employed in nongregarious species, combined with overlapping space use of distinct matrilineal clusters, leads to a strong downward bias when mtDNA lineage membership is ignored. Thus, in nongregarious species, correct inferences of dispersal can only be achieved by combining several genetic approaches with detailed spatial information.     

Comparative toxicity of nanoparticulate CuO and ZnO to soil bacterial communities

The increasing industrial application of metal oxide Engineered Nano-Particles (ENPs) is likely to increase their environmental release to soils. While the potential of metal oxide ENPs as environmental toxicants has been shown, lack of suitable control treatments have compromised the power of many previous assessments. We evaluated the ecotoxicity of ENP (nano) forms of Zn and Cu oxides in two different soils by measuring their ability to inhibit bacterial growth. We could show a direct acute toxicity of nano-CuO acting on soil bacteria while the macroparticulate (bulk) form of CuO was not toxic. In comparison, CuSO(4) was more toxic than either oxide form. Unlike Cu, all forms of Zn were toxic to soil bacteria, and the bulk-ZnO was more toxic than the nano-ZnO. The ZnSO(4) addition was not consistently more toxic than the oxide forms. Consistently, we found a tight link between the dissolved concentration of metal in solution and the inhibition of bacterial growth. The inconsistent toxicological response between soils could be explained by different resulting concentrations of metals in soil solution. Our findings suggested that the principal mechanism of toxicity was dissolution of metal oxides and sulphates into a metal ion form known to be highly toxic to bacteria, and not a direct effect of nano-sized particles acting on bacteria. We propose that integrated efforts toward directly assessing bioavailable metal concentrations are more valuable than spending resources to reassess ecotoxicology of ENPs separately from general metal toxicity.     

The Multi-PDZ domain protein MUPP1 as a lipid raft-associated scaffolding protein controlling the acrosome reaction in mammalian spermatozoa

The success of acrosomal exocytosis, a complex process with a variety of interrelated steps, relies on the coordinated interaction of participating signaling molecules. Since scaffolding proteins are known to spatially organize sequential signaling pathways, we examined whether the Multi-PDZ domain protein MUPP1, recently identified in mammalian spermatozoa, is functionally active in controlling acrosomal secretion in mammalian sperm cells. To address this question, permeabilized mouse sperm were loaded with inhibitory antibodies against MUPP1 as well as with a photosensitive Ca(2+) chelator which allows a controlled release of acrosomal Ca(2+). The results revealed that MUPP1 controls initial tethering and docking of the acrosomal vesicle, whereas syntaxin 2, a t-SNARE protein also expressed in the acrosomal cap of mammalian spermatozoa, appears to take part in the final process of acrosomal fusion. Interestingly, using immunogold electron microscopy, it was found that MUPP1 is detectable in the region of the periacrosomal membrane. Furthermore, in isolated detergent-insoluble glycolipid-enriched membrane domains from epididymal spermatozoa, MUPP1 was found to show a striking association with the Triton X-100 insoluble membrane fraction, which did not change significantly upon sperm capacitation or partial chemical extraction of cholesterol. This evidence points to a role of MUPP1 as a membrane raft-associated molecular organizer, and suggests that mammalian spermatozoa may use a scaffolding protein and distinct membrane subdomains to spatially organize components involved in the process of acrosomal exocytosis.     

Proenkephalin expression and enkephalin release are widely observed in non-neuronal tissues

Enkephalins are opioid peptides that are found at high levels in the brain and endocrine tissues. Studies have shown that enkephalins play an important role in behavior, pain, cardiac function, cellular growth, immunity, and ischemic tolerance. Our global hypothesis is that enkephalins are released from non-neuronal tissues in response to brief ischemia or exercise, and that this release contributes to cardioprotection. To identify tissues that could serve as potential sources of enkephalins, we used real-time PCR, Western blot analysis, ELISA, immunofluorescence microscopy, and ex vivo models of enkephalin release. We found widespread expression of preproenkephalin (pPENK) mRNA and production of the enkephalin precursor protein proenkephalin (PENK) in rat and mouse tissues, as well as in tissues and cells from humans and pigs. Immunofluorescence microscopy with anti-enkephalin antisera demonstrated immunoreactivity in rat tissues, including heart and skeletal muscle myocytes, intestinal and kidney epithelium, and intestinal smooth muscle cells. Finally, isolated tissue studies showed that heart, skeletal muscle, and intestine released enkephalins ex vivo. Together our studies indicate that multiple non-neuronal tissues produce PENK and release enkephalins. These data support the hypothesis that non-neuronal tissues could play a role in both local and systemic enkephalin-mediated effects.     

Hybridization and crossability in Caiophora (Loasaceae subfam. Loasoideae): Are interfertile species and inbred populations results of a recent radiation?

Interspecific hybridization is considered a possible mechanism of plant diversification. The Andes are a hotspot of biodiversity, but hybridization in Andean taxa has so far not been investigated intensively. The current study investigates crossability in Caiophora (Loasaceae subfam. Loasoideae) by experimental interspecific hybridization of seven different species. Hand pollination was undertaken, developing fruits counted, thousand (seed) grain weights, and seed viability were examined. Cross pollination led to some fruit set in 36 of the 37 different combinations. Overall fruit set was virtually identical irrespective of the combination of parental plants. Mean germination rates were much higher in hybrid seeds, indicating a marked heterosis effect and the possible presence of an inbreeding depression in the source populations: In experimental hybridization the divergent taxa of Caiophora behave like isolated, inbred populations of a single species. Allopatry and different habitat preferences seem to be the key factors keeping the (interfertile) taxa of Caiophora apart in the apparent absence of both postmating isolating mechanisms and obvious isolating mechanisms in phenology and floral biology. Interspecific hybrids reported from the wild appear to be the result of secondary contact due to human impact.     

Effects of prey type on suspension-feeding behavior in Nile tilapia

Using freshly collected field samples and enrichment cultures, eight genera of cryptomonads from the Salton Sea are recorded for the first time. Comparative data from light and scanning electron microscopy were utilized to identify these genera and species. The genera included Chroomonas, Falcomonas, Hemiselmis, Plagioselmis, Pyrenomonas/Rhodomonas, Storeatula, Teleaulax, and the kathablepharid Leucocryptos. One putative genus remains unidentified and may represent a new taxon. SEM has not been conducted on this cryptomonad, but it has been isolated and is being maintained in culture. The genera and species identified from the Salton Sea are typical of marine rather then freshwater environments and may play an important role in primary productivity and as preferred food organisms for zooplankton.     

Programming of poliovirus inhibition of deoxyribonucleic acid synthesis in HeLa cells

Ackermann, W. W. (The University of Michigan, Ann Arbor), and D. Wahl. Programming of poliovirus inhibition of deoxyribonucleic acid synthesis in HeLa cells. J. Bacteriol. 92:1051-1054. 1966.-Deletion of arginine from a culture medium reduced the rate of deoxyribonucleic acid (DNA) synthesis in uninfected HeLa cells. The normal rate was promptly restored by addition of arginine. Deletion of arginine also prevented poliovirus from inhibiting DNA synthesis in HeLa cells. However, the inhibitory potential of the infection and the capacity of the host cell for stimulation with regard to DNA synthesis were both retained in arginine-depleted cells which were infected. Upon addition of arginine late in the infection, DNA synthesis was first stimulated and then inhibited.     

Effect of the phosphonic acid derivatives ethephon and trichlorphon on the incorporation in vivo of (14C)-acetate into cholesterol and other lipids in rats

The effect of the phosphonic acid derivatives Ethephon and Trichlorphon on the incorporation of 14C-labelled acetate into lipids especially cholesterol was investigated. Adult Wistar rats were fed for 7 days diets containing 50 and 500 ppm, respectively, of the phosphonic acid derivatives. Both compounds caused a significant increase of the 14C-activity in lipids of serum, liver, heart, and brain. The effect of Ethephon was significantly more intense than that of Trichlorphon. The important finding was the Ethephon-induced increase of the [14C]-acetate incorporation into cholesterol which continued across all the tissues studied.