The morphology,innervation and neural control of the anterior arterial system of Aplysia californica

Summary The morphology, innervation, and neural control of the anterior arterial system of Aplysia californica were investigated. Immunocytochemical and histochemical techniques generated positive reactions in the anterior arterial system for several neuroactive substances, including SCP_B, FMRFamide, R151 peptide, dopamine and serotonin. Three neurons were found to innervate the rostral portions of the anterior arterial tree. One is the identified peptidergic neuron R15 in the abdominal ganglion, and the other two are a pair of previously unidentified neurons, one in each pedal ganglion, named pedal arterial shorteners (P_AS)- The endogeneously bursting neuron R15 was found to innervate the proximal anterior aorta. It also innervates a branch of the distal anterior aorta, the left pedal-parapodial artery. Activity in R15 causes constriction of the left pedal-parapodial artery. This effect is presumed to direct hemolymph towards the genital groove and penis on the right side in vivo. This vasoconstrictor action of R15 is mimicked by the R151 peptide. The P_AS neuron pair causes longitudinal contraction of the rostral anterior aorta and the pedal-parapodial arteries. In vivo, the pair is active during behaviors involving head withdrawal and turning. By adjusting the length of the arteries during postural changes, the P_AS neurons may prevent disturbances in blood flow due to bending or kinking of the arterial walls.     

Control of regeneration and morphogenesis by divalent cations in Acetabularia mediterranea

A study of the effects of altered calcium and magnesium levels on the capacities of Acetabularia plants to elongate and to form whorls or caps revealed sharp transitions of regenerative state over small concentration changes of external calcium at both reduced and elevated levels. Cobalt and lanthanum, which interfere with calcium fluxes across membranes, also affect regeneration and morphogenesis with sharply defined transition ranges. It is shown that these effects are localized at the growing tip. The nature of the mechanisms involved in the transitions from one morphogenetic state to another in the regenerative process is considered.     

A new precursor for organo-osmium complexes

The use of potassium osmate, K₂[OsO₂(OH)₄], as a precursor for some cyclopentadienyl-osmium complexes is described. The X-ray structures of OsBr(PPh₃)₂Cp, OsCl(dppe)Cp and OsX(dppe)Cp^∗ (X = Cl, Br) are reported.     

Synthesis and Transfection Efficiencies of Divalent Ammonium Headgroup Cationic Lipids with Different Hydrophobic Tails

Russian Journal of Bioorganic Chemistry - Cationic lipids with amide or carbamate linker and divalent cationic headgroups were synthesized for a transfection study. Sixteen cationic lipids with...     

Trophic ecology of a freshwater sponge (Spongilla lacustris) revealed by stable isotope analysis

The vital roles that sponges play in marine habitats are well-known. However, sponges inhabiting freshwaters have been largely ignored despite having widespread distributions and often high local abundances. We used natural abundance stable isotope signatures of carbon and nitrogen (δ ¹³C and δ ¹⁵N) to infer the primary food source of the cosmopolitan freshwater sponge Spongilla lacustris. Our results suggest that S. lacustris feed largely on pelagic resources and may therefore link pelagic and benthic food webs. A facultative association between S. lacustris and endosymbiotic green algae caused S. lacustris to have significantly depleted carbon and nitrogen signatures that may reflect carbon and nitrogen exchange between sponges and their symbiotic algae. Isotopic data from specialist sponge consumers demonstrated that sponges hosting zoochlorellae were the major component of the diet of the spongillafly Climacia areolaris and the sponge-eating caddisfly Ceraclea resurgens suggesting that the symbiosis between freshwater sponges and algae is important to sponge predator trophic ecology. Our results help define the role of sponges in freshwater ecosystems and shed new light on the evolution and ecological consequences of a complex tri-trophic symbiosis involving freshwater sponges, zoochlorellae, and spongivorous insects.     

Plasticity of mycangia in Xylosandrus ambrosia beetles

Insects that depend on microbial mutualists evolved a variety of organs to transport the microsymbionts while dispersing. The ontogeny and variability of such organs is rarely studied, and the microsymbiont*s effects on the animal tissue development remain unknown in most cases. Ambrosia beetles (Coleoptera: Curculionidae: Scolytinae or Platypodinae) and their mutualistic fungi are an ideal system to study the animalfungus interactions. While the interspecific diversity of their fungus transport organ一 mycangia—is well-known, their developmental plasticity has been poorly described. To determine the ontogeny of the mycangium and the influence of the symbiotic fungus on the tissue development, we dissected by hand or scanned with micro-CT the mycangia in various developmental stages in five Xylosandrus ambrosia beetle species that possess a large, mesonotal mycangium: Xylosandrus amputatus. Xylosandrus compactus, Xylosandrus crassiusculus, Xylosandrus discolor, and Xylosandrus germanus. We processed 181 beetle samples from the United States and China. All five species displayed three stages of the mycangium development:(1) young teneral adults had an empty, deflated and cryptic mycangium without fungal mass;(2) in fully mature adults during dispersal, the promesonotal membrane was inflated, and most individuals developed a mycangium mostly filled with the symbiont, though size and symmetry varied;and (3) after successful establishment of their new galleries, most females discharged the bulk of the fun gal inoculum and deflated the mycangium. Experimental aposymbiotic individuals demonstrated that the pronotal membrane invaginated independently of the presence of the fungus, but the fungus was required for inflation. Mycangia are more dynamic than previously thought, and their morphological changes correspond to the phases of the symbiosis. Importantly, studies of the fungal symbionts or plant pathogen transmission in ambrosia beetles need to consider which developmental stage to sample. We provide illustrations of the different stages, including microphotography of dissections and micro-CT scans.     

A plasmid-based reverse genetics system for animal double-stranded RNA viruses

Mammalian orthoreoviruses (reoviruses) are highly tractable experimental models for studies of double-stranded (ds) RNA virus replication and pathogenesis. Reoviruses infect respiratory and intestinal epithelium and disseminate systemically in newborn animals. Until now, a strategy to rescue infectious virus from cloned cDNA has not been available for any member of the Reoviridae family of dsRNA viruses. We report the generation of viable reovirus following plasmid transfection of murine L929 (L) cells using a strategy free of helper virus and independent of selection. We used the reovirus reverse genetics system to introduce mutations into viral capsid proteins sigma1 and sigma3 and to rescue a virus that expresses a green fluorescent protein (GFP) transgene, thus demonstrating the tractability of this technology. The plasmid-based reverse genetics approach described here can be exploited for studies of reovirus replication and pathogenesis and used to develop reovirus as a vaccine vector.     

Proteomic and microarray analyses of the Dictyostelium Zak1-GSK-3 signaling pathway reveal a role in early development

GskA, the Dictyostelium GSK-3 orthologue, is modified and activated by the dual-specificity tyrosine kinase Zak1, and the two kinases form part of a signaling pathway that responds to extracellular cyclic AMP. We identify potential cellular effectors for the two kinases by analyzing the corresponding null mutants. There are proteins and mRNAs that are altered in abundance in only one or the other of the two mutants, indicating that each kinase has some unique functions. However, proteomic and microarray analyses identified a number of proteins and genes, respectively, that are similarly misregulated in both mutant strains. The positive correlation between the array data and the proteomic data is consistent with the Zak1-GskA signaling pathway's functioning by directly or indirectly regulating gene expression. The discoidin 1 genes are positively regulated by the pathway, while the abundance of the H5 protein is negatively regulated. Two of the targets, H5 and discoidin 1, are well-characterized markers for early development, indicating that the Zak1-GskA pathway plays a role in development earlier than previously observed.     

Descriptive study of cooperative language in primary care consultations by male and female doctors

ObjectiveTo compare the use of some of the characteristics of male and female language by male and female primary care practitioners during consultations.DesignDoctors’ use of the language of dominance and support was explored by using concordancing software. Three areas were examined: mean number of words per consultation; relative frequency of question tags; and use of mitigated directives. The analysis of language associated with cooperative talk examines relevant words or phrases and their immediate context.Subjects26 male and 14 female doctors in general practice, in a total of 373 consecutive consultations.SettingWest Midlands.ResultsDoctors spoke significantly more words than patients, but the number of words spoken by male and female doctors did not differ significantly. Question tags were used far more frequently by doctors (P<0.001) than by patients or companions. Frequency of use was similar in male and female doctors, and the speech styles in consultation were similar.ConclusionsThese data show that male and female doctors use a speech style which is not gender specific, contrary to findings elsewhere; doctors consulted in an overtly non-directive, negotiated style, which is realised through suggestions and affective comments. This mode of communication is the core teaching of communication skills courses. These results suggest that men have more to learn to achieve competence as professional communicators.

Key messages

• Standard teaching on medical communication promotes a cooperative approach to doctor-patient interaction
• In everyday life, however, cooperative language is more typical of female speech style, and this suggests that male doctors may find it harder to develop appropriate consulting styles; in a sample of 373 consultations, male and female general practitioners used examples of cooperative language equally
• Language based study of doctor-patient interaction can deepen understanding and provide useful insights