A New Species of Allosathes Gaud, Atyeo & Berla (Astigmata: Crypturoptidae) on Feathers of the Chilean Tinamou, Nothoprocta perdicaria (Tinamiformes: Tinamidae) in Chile

Allosathes anitae n. sp. Casanueva & González-Acu?a (Astigmata: Crypturoptidae), collected on the Chilean tinamou Nothoprocta perdicaria (Tinamiformes: Tinamidae) from different localities of the ?uble Province, Chile, is described. Comments on its affinities and differences with Allosathes anepiandrius Gaud, Atyeo & Berla are also included.     

TRAINING NEEDS ASSESSMENT IN RESEARCH ETHICS EVALUATION AMONG RESEARCH ETHICS COMMITTEE MEMBERS IN THREE AFRICAN COUNTRIES: CAMEROON,MALI AND TANZANIA

Background: As actors with the key responsibility for the protection of human research participants, Research Ethics Committees (RECs) need to be competent and well‐resourced in order to fulfil their roles. Despite recent programs designed to strengthen RECs in Africa, much more needs to be accomplished before these committees can function optimally. Objective: To assess training needs for biomedical research ethics evaluation among targeted countries. Methods: Members of RECs operating in three targeted African countries were surveyed between August and November 2007. Before implementing the survey, ethical approvals were obtained from RECs in Switzerland, Cameroon, Mali and Tanzania. Data were collected using a semi‐structured questionnaire in English and in French. Results: A total of 74 respondents participated in the study. The participation rate was 68%. Seventy one percent of respondents reported having received some training in research ethics evaluation. This training was given by national institutions (31%) and international institutions (69%). Researchers and REC members were ranked as the top target audiences to be trained. Of 32 topics, the top five training priorities were: basic ethical principles, coverage of applicable laws and regulations, how to conduct ethics review, evaluating informed consent processes and the role of the REC. Conclusion: Although the majority of REC members in the targeted African countries had received training in ethics, they expressed a need for additional training. The results of this survey have been used to design a training program in research ethics evaluation that meets this need.     

Oligomerization of the voltage-gated proton channel

The voltage-gated proton channel exists as a dimer, although each protomer has a separate conduction pathway, and when forced to exist as a monomer, most major functions are retained. However, the proton channel protomers appear to interact during gating. Proton channel dimerization is thought to result mainly from coiled-coil interaction of the intracellular C-termini. Several types of evidence are discussed that suggest that the dimer conformation may not be static, but is dynamic and can sample different orientations. Zn²⁺ appears to link the protomers in an orientation from which the channel(s) cannot open. A tandem WT-WT dimer exhibits signs of cooperative gating, indicating that despite the abnormal linkage, the correct orientation for opening can occur. We propose that C-terminal interaction functions mainly to tether the protomers together. Comparison of the properties of monomeric and dimeric proton channels speaks against the hypothesis that enhanced gating reflects monomer-dimer interconversion.Key words: voltage-gated proton channels, voltage gating, voltage-sensing domains, phagocytes, coiled-coil, oligomerization, proton currents, pH, dimerization, C-terminus     

移植的5—羟色胺能神经元跨软脊膜迁入大鼠脊髓的研究

本文对移植的5-HT神经元从蛛网膜下腔跨软脊膜迁移进入脊髓作了初步研究。将含有5-HT细胞的胚胎中缝核组织小块或神经细胞悬浮液作为移植物,以5-HT免疫组织化学方法跟踪移植细胞,结果如下:(1)在低胸水平横切脊髓,10d后,横断脊髓内的5-HT纤维消失。(2)横切脊髓(方法同上)后,立即将中缝核组织小块移植在胸腰段脊髓的蛛网膜下腔,一月后.在横断脊髓内出现5-HT阳性神经元和纤维。5-HT纤维能在灰白质内延伸。(3)脊髓横断后,若以中缝核的细胞悬浮液代替组织小块,作上述移植,则在移植区附近的灰质内出现大量的5-HT阳性神经元。这些神经元在灰质内的分布范围与神经细胞悬浮液在蛛网膜下腔的移植范围相一致。迁入神经元能在灰质内重新形成5-HT阳性纤维网。(4)经上述移植后,灰质内出现的5-HT阳性纤维随远离细胞体而变得稀疏。白质内的5-HT阳性纤维远比灰质内稀少。本实验结果表明:移植在脊髓蛛网膜下腔的脑干5-HT细胞能跨软脊膜迁移进入脊髓。     

Optimal range of prey size for antlions

1. Antlions are opportunistic trap building predators that cannot control prey encounter. Their trap should ideally retain a great diversity of prey. However, building a single trap that captures many prey with varying characteristics can be challenging. 2. A series of five different ant species ranging from thin to large, of sizes ranging from 2.75 to 6.5 mm, and a mean weight ranging from 0.54 to 6.00 mg were offered in a random succession to antlions. The state of satiation of the antlions was controlled, and their mass and the depth of their pit were recorded. The reaction of antlion to the prey, the probability of capture as well as the time to escape were recorded. 3. The probability of an antlion reaction is an increasing function of the pit depth and a decreasing function of antlion mass. The probability of capture is highest for intermediate prey mass and is an increasing function of pit depth. The time to escape is a declining function of prey mass and an increasing function of pit depth. 4. There is an upper limit to prey mass given that large prey escape out of the pit. There is a lower limit to prey mass given the difficulty to apprehend the smallest, thin species. Consequently, there is a range of prey mass, corresponding to a medium‐sized ant of 2 mg, for which the pit functions best. The physics of insect locomotion on sandy slopes was identified as the key to understanding the functioning of antlion pits.     

Molecular phylogenetic evidence that the phylum Haplosporidia has an alveolate ancestry

The phylogenetic position of the phylum Haplosporidia among other protists was investigated with the complete 16S-like rRNA gene sequences from two species in the phylum: Haplosporidium nelsoni, a parasite of oysters, and Minchinia teredinis, a parasite of shipworms. Because the lack of obvious morphological homologies with other protists hampered decisions regarding taxonomic composition for sequence alignment and phylogenetic analysis, the complete sequences for these two haplosporidians were directed as search queries to the blast/ncbi.nlm.nih.gov electronic mail server. The results of this heuristic similarity search provided a basis for constructing a preliminary higher-taxonomic-level analysis comparing the haplosporidians with species from the slime molds, fungi, algae, amoebae, ciliates, dinoflagellates, and apicomplexans. Maximum parsimony yielded equivocal results, whereas transversionally weighted parsimony suggested an affinity with the alveolates (i.e., the ciliates, dinoflagellates, and apicomplexans). Multiple alignment of the two haplosporidian sequences against 17 taxa in a secondary analysis focusing on the alveolates and subsequent parsimony analysis placed the phylum Haplosporidia as a monophyletic group within the Alveolata and as a taxon of equal rank with the other three alveolate phyla. The precise placement within the Alveolata was sensitive to weighting.      

A requirement for trypsin-sensitive cell-surface components for cell-cell interactions of embryonic neural retina cells

A quantitative assay was used to measure the rate of collection of a population of embryonic neural retina cells to the surface of cell aggregates. The rate of collection of freshly trysinized cells was limited in the initial stages by the rate of replacement of trypsin-sensitive cell- surface components. When cells were preincubated, or "recovered," and then added to cell aggregates, collection occurred at a linear rate and was independent of protein and glycoprotein synthesis. The adhesion of recovered cells was temperature and energy dependent, and was reversibly inhibited by cytochalasin B. Colchicine had little effect on collection of recovered cells. Antiserum directed against recovered cell membranes was shown to bind to recovered cells by indirect immunofluorescence. The antiserum also was shown to inhibit collection of recovered cells to aggregates, suggesting that at least some of the antigens identified might be involved in the adhesion process. The inhibitory effect of the antiserum was dose dependent . Freshly trypsinized cells absorbed neither the immunofluorescence activity nor the adhesion-inhibiting activity. Recovered cells absorbed away both activities. In specificity studies, dorsal neural retina cells adhered to aggregates of ventral optic tectum in preference to aggregates of dorsal optic tectum. The adhesive specificity of the dorsal retina cells was less sensitive to trypsin than the adhesive specificity of ventral retina cells which adhered preferentially to dorsal tectal aggregates only after a period of recovery.     

hierfstat,a package for r to compute and test hierarchical F‐statistics

The package hierfstat for the statistical software r , created by the R Development Core Team, allows the estimate of hierarchical F‐statistics from a hierarchy with any numbers of levels. In addition, it allows testing the statistical significance of population differentiation for these different levels, using a generalized likelihood‐ratio test. The package hierfstat is available at http://www.unil.ch/popgen/softwares/hierfstat.htm .