Raspailiidae (Porifera: Demospongiae: Axinellida) from the Mexican Pacific Ocean with the description of seven new species

The taxonomy of the family Raspailiidae has always been controversial. The family was first included in the order Poecilosclerida. It was then allocated to the order Axinellida and later moved back to Poecilosclerida. Currently with the development of molecular tools it has been assigned to the order Axinellida. In this contribution we describe 10 species from the Mexican Pacific Ocean. Seven of them are new to science: Raspailia (Parasyringella) rubra sp. nov., Raspailia (Raspaxilla) hymani (Dickinson 1945 Dickinson, MG. 1945. Sponges on the Gulf of California. Allan Hancock Pac Exp, 11(1): 1–251.  [Google Scholar]), Raspailia (Raspaxilla) hyle (de Laubenfels 1930 de Laubenfels, MW. 1930. The sponges of California. (Abstracts of dissertations for the degree of doctor of philosophy). Stanford Univ Bull, 5(98): 24–29.  [Google Scholar]), Aulospongus cerebella (Dickinson 1945 Dickinson, MG. 1945. Sponges on the Gulf of California. Allan Hancock Pac Exp, 11(1): 1–251.  [Google Scholar]), Aulospongus californianus sp. nov., Aulospongus aurantiacus sp. nov., Eurypon patriciae sp. nov., Eurypon tylospinosum sp. nov., Eurypon diversicolor sp. nov. and Eurypon brunus sp. nov. We discuss the genus Eurypon and include a table for all the species described worldwide with some comments about this genus. http://www.zoobank.org/urn:lsid:zoobank.org:pub:D462084B-EE9C-4C61-884A-C9DB70003B4A     

Light on the structure of thromboxane A2 receptor heterodimers

The structure-based design of a mutant form of the thromboxane A(2) prostanoid receptor (TP) was instrumental in characterizing the structural determinants of the hetero-dimerization process of this G protein coupled receptor (GPCR). The results suggest that the hetero-dimeric complexes between the TPα and β isoforms are characterized by contacts between hydrophobic residues in helix 1 from both monomers. Functional characterization confirms that TPα-TPβ hetero-dimerization serves to regulate TPα function through agonist-induced internalization, with important implications in cardiovascular homeostasis. The integrated approach employed in this study can be adopted to gain structural and functional insights into the dimerization/oligomerization process of all GPCRs for which the structural model of the monomer can be achieved at reasonable atomic resolution.     

Origin of AIDS: contaminated polio vaccine theory refuted

Despite strong evidence to the contrary, speculation continues that the AIDS virus, human immunodeficiency virus type 1 (HIV-1), may have crossed into humans as a result of contamination of the oral polio vaccine (OPV). This 'OPV/AIDS theory' claims that chimpanzees from the vicinity of Stanleyville--now Kisangani in the Democratic Republic of Congo--were the source of a simian immunodeficiency virus (SIVcpz) that was transmitted to humans when chimpanzee tissues were allegedly used in the preparation of OPV. Here we show that SIVcpz is indeed endemic in wild chimpanzees of this region but that the circulating virus is phylogenetically distinct from all strains of HIV-1, providing direct evidence that these chimpanzees were not the source of the human AIDS pandemic.     

The knockout mouse project

Mouse knockout technology provides a powerful means of elucidating gene function in vivo, and a publicly available genome-wide collection of mouse knockouts would be significantly enabling for biomedical discovery. To date, published knockouts exist for only about 10% of mouse genes. Furthermore, many of these are limited in utility because they have not been made or phenotyped in standardized ways, and many are not freely available to researchers. It is time to harness new technologies and efficiencies of production to mount a high-throughput international effort to produce and phenotype knockouts for all mouse genes, and place these resources into the public domain.     

An age-colour relationship for main-belt S-complex asteroids

Asteroid collisions in the main belt eject fragments that may eventually land on Earth as meteorites. It has therefore been a long-standing puzzle in planetary science that laboratory spectra of the most populous class of meteorite (ordinary chondrites, OC) do not match the remotely observed surface spectra of their presumed (S-complex) asteroidal parent bodies. One of the proposed solutions to this perplexing observation is that 'space weathering' modifies the exposed planetary surfaces over time through a variety of processes (such as solar and cosmic ray bombardment, micro-meteorite bombardment, and so on). Space weathering has been observed on lunar samples, in Earth-based laboratory experiments, and there is good evidence from spacecraft data that the process is active on asteroid surfaces. Here, we present a measurement of the rate of space weathering on S-complex main-belt asteroids using a relationship between the ages of asteroid families and their colours. Extrapolating this age-colour relationship to very young ages yields a good match to the colour of freshly cut OC meteorite samples, lending strong support to a genetic relationship between them and the S-complex asteroids.     

Antagonistic pathways in neurons exposed to body fluid regulate social feeding in Caenorhabditis elegans

Wild isolates of Caenorhabditis elegans can feed either alone or in groups. This natural variation in behaviour is associated with a single residue difference in NPR-1, a predicted G-protein-coupled neuropeptide receptor related to Neuropeptide Y receptors. Here we show that the NPR-1 isoform associated with solitary feeding acts in neurons exposed to the body fluid to inhibit social feeding. Furthermore, suppressing the activity of these neurons, called AQR, PQR and URX, using an activated K(+) channel, inhibits social feeding. NPR-1 activity in AQR, PQR and URX neurons seems to suppress social feeding by antagonizing signalling through a cyclic GMP-gated ion channel encoded by tax-2 and tax-4. We show that mutations in tax-2 or tax-4 disrupt social feeding, and that tax-4 is required in several neurons for social feeding, including one or more of AQR, PQR and URX. The AQR, PQR and URX neurons are unusual in C. elegans because they are directly exposed to the pseudocoelomic body fluid. Our data suggest a model in which these neurons integrate antagonistic signals to control the choice between social and solitary feeding behaviour.     

Increasing dominance of large lianas in Amazonian forests

Ecological orthodoxy suggests that old-growth forests should be close to dynamic equilibrium, but this view has been challenged by recent findings that neotropical forests are accumulating carbon and biomass, possibly in response to the increasing atmospheric concentrations of carbon dioxide. However, it is unclear whether the recent increase in tree biomass has been accompanied by a shift in community composition. Such changes could reduce or enhance the carbon storage potential of old-growth forests in the long term. Here we show that non-fragmented Amazon forests are experiencing a concerted increase in the density, basal area and mean size of woody climbing plants (lianas). Over the last two decades of the twentieth century the dominance of large lianas relative to trees has increased by 1.7-4.6% a year. Lianas enhance tree mortality and suppress tree growth, so their rapid increase implies that the tropical terrestrial carbon sink may shut down sooner than current models suggest. Predictions of future tropical carbon fluxes will need to account for the changing composition and dynamics of supposedly undisturbed forests.