Alarm Pheromone Composition and Behavioral Activity in Fungus-Growing Ants.

Chemical communication is a dominant method of communication throughout the animal kingdom and can be especially important in group-living animals in which communicating threats, either from predation or other dangers, can have large impacts on group survival. Social insects, in particular, have evolved a number of pheromonal compounds specifically to signal alarm. There is predicted to be little selection for interspecific variation in alarm cues because individuals may benefit from recognizing interspecific as well as conspecific cues and, consequently, alarm cues are not normally thought to be used for species or nestmate recognition. Here, we examine the composition of the alarm pheromones of seven species of fungus-growing ants (Attini), including both basal and derived species and examine the behavioral responses to alarm pheromone of Acromyrmex leaf-cutting ants, the sister genus to the highly studied Atta leaf-cutting ants. We find surprisingly high interspecific variation in alarm pheromone composition across the attine phylogeny. Interestingly, the active component of the alarm pheromone was different between the two leaf-cutting ant genera. Furthermore, in contrast to previous studies on Atta, we found no differences among morphological castes in their responses to alarm pheromone in Acromyrmex but we did find differences in responses among putative age classes. The results suggest that the evolution of alarm communication and signaling within social insect clades can be unexpectedly complex and that further work is warranted to understand whether the evolution of different alarm pheromone compounds is adaptive

The role of juvenile hormone in regulating reproductive physiology and dominance in Dinoponera quadriceps ants

Unequal reproductive output among members of the same sex (reproductive skew) is a common phenomenon in a wide range of communally breeding animals. In such species, reproductive dominance is often acquired during antagonistic interactions between group members that establish a reproductive hierarchy in which only a few individuals reproduce. Rank-specific syndromes of behavioural and physiological traits characterize such hierarchies, but how antagonistic behavioural interactions translate into stable rank-specific syndromes remains poorly understood. The pleiotropic nature of hormones makes them prime candidates for generating such syndromes as they physiologically integrate environmental (social) information, and often affect reproduction and behaviour simultaneously. Juvenile hormone (JH) is one of several hormones that occupy such a central regulatory role in insects and has been suggested to regulate reproductive hierarchies in a wide range of social insects including ants. Here we use experimental manipulation to investigate the effect of JH levels on reproductive physiology and social dominance in high-ranked workers of the eusocial ant Dinoponera quadriceps, a species that has secondarily reverted to queenless, simple societies. We show that JH regulated reproductive physiology, with ants in which JH levels were experimentally elevated having more regressed ovaries. In contrast, we found no evidence of JH levels affecting dominance in social interactions. This could indicate that JH and ovary development are decoupled from dominance in this species, however only high-ranked workers were investigated. The results therefore confirm that the regulatory role of JH in reproductive physiology in this ant species is in keeping with its highly eusocial ancestors rather than its secondary reversion to simple societies, but more investigation is needed to disentangle the relationships between hormones, behaviour and hierarchies

A review of elliptical and disc galaxy structure, and modern scaling laws

A century ago, in 1911 and 1913, Plummer and then Reynolds introduced their models to describe the radial distribution of stars in `nebulae'. This article reviews the progress since then, providing both an historical perspective and a contemporary review of the stellar structure of bulges, discs and elliptical galaxies. The quantification of galaxy nuclei, such as central mass deficits and excess nuclear light, plus the structure of dark matter halos and cD galaxy envelopes, are discussed. Issues pertaining to spiral galaxies including dust, bulge-to-disc ratios, bulgeless galaxies, bars and the identification of pseudobulges are also reviewed. An array of modern scaling relations involving sizes, luminosities, surface brightnesses and stellar concentrations are presented, many of which are shown to be curved. These 'redshift zero' relations not only quantify the behavior and nature of galaxies in the Universe today, but are the modern benchmark for evolutionary studies of galaxies, whether based on observations, N-body-simulations or semi-analytical modelling. For example, it is shown that some of the recently discovered compact elliptical galaxies at 1.5 < z < 2.5 may be the bulges of modern disc galaxies.Comment: Condensed version (due to Contract) of an invited review article to appear in "Planets, Stars and Stellar Systems"(www.springer.com/astronomy/book/978-90-481-8818-5). 500+ references incl. many somewhat forgotten, pioneer papers. Original submission to Springer: 07-June-201

Tyrosine Sulfation of Native Mouse Psgl-1 Is Required for Optimal Leukocyte Rolling on P-Selectin In Vivo

We recently demonstrated that tyrosine sulfation is an important contributor to monocyte recruitment and retention in a mouse model of atherosclerosis. P-selectin glycoprotein ligand-1 (Psgl-1) is tyrosine-sulfated in mouse monocyte/macrophages and its interaction with P-selectin is important in monocyte recruitment in atherosclerosis. However, whether tyrosine sulfation is required for the P-selectin binding function of mouse Psgl-1 is unknown. Here we test the function of native Psgl-1 expressed in leukocytes lacking endogenous tyrosylprotein sulfotransferase (TPST) activity.Psgl-1 function was assessed by examining P-selectin dependent leukocyte rolling in post-capillary venules of C57BL6 mice transplanted with hematopoietic progenitors from wild type (WT → B6) or Tpst1;Tpst2 double knockout mice (Tpst DKO → B6) which lack TPST activity. We observed that rolling flux fractions were lower and leukocyte rolling velocities were higher in Tpst DKO → B6 venules compared to WT → B6 venules. Similar results were observed on immobilized P-selectin in vitro. Finally, Tpst DKO leukocytes bound less P-selectin than wild type leukocytes despite equivalent surface expression of Psgl-1.These findings provide direct and convincing evidence that tyrosine sulfation is required for optimal function of mouse Psgl-1 in vivo and suggests that tyrosine sulfation of Psgl-1 contributes to the development of atherosclerosis

A computational model of lipopolysaccharide-induced nuclear factor kappa B activation:a key signalling pathway in infection-induced preterm labour

Preterm birth is the single biggest cause of significant neonatal morbidity and mortality, and the incidence is rising. Development of new therapies to treat and prevent preterm labour is seriously hampered by incomplete understanding of the molecular mechanisms that initiate labour at term and preterm. Computational modelling provides a new opportunity to improve this understanding. It is a useful tool in (i) identifying gaps in knowledge and informing future research, and (ii) providing the basis for an in silico model of parturition in which novel drugs to prevent or treat preterm labour can be "tested". Despite their merits, computational models are rarely used to study the molecular events initiating labour. Here, we present the first attempt to generate a dynamic kinetic model that has relevance to the molecular mechanisms of preterm labour. Using published data, we model an important candidate signalling pathway in infection-induced preterm labour: that of lipopolysaccharide (LPS) -induced activation of Nuclear Factor kappa B. This is the first model of this pathway to explicitly include molecular interactions upstream of Nuclear Factor kappa B activation. We produced a formalised graphical depiction of the pathway and built a kinetic model based on ordinary differential equations. The kinetic model accurately reproduced published in vitro time course plots of Lipopolysaccharide-induced Nuclear Factor kappa B activation in mouse embryo fibroblasts. In this preliminary work we have provided proof of concept that it is possible to build computational models of signalling pathways that are relevant to the regulation of labour, and suggest that models that are validated with wet-lab experiments have the potential to greatly benefit the field

Comparative genomics reveals diversity among xanthomonads infecting tomato and pepper

<p>Abstract</p> <p>Background</p> <p>Bacterial spot of tomato and pepper is caused by four <it>Xanthomonas </it>species and is a major plant disease in warm humid climates. The four species are distinct from each other based on physiological and molecular characteristics. The genome sequence of strain 85-10, a member of one of the species, <it>Xanthomonas euvesicatoria </it>(<it>Xcv</it>) has been previously reported. To determine the relationship of the four species at the genome level and to investigate the molecular basis of their virulence and differing host ranges, draft genomic sequences of members of the other three species were determined and compared to strain 85-10.</p> <p>Results</p> <p>We sequenced the genomes of <it>X. vesicatoria </it>(<it>Xv</it>) strain 1111 (ATCC 35937), <it>X. perforans </it>(<it>Xp</it>) strain 91-118 and <it>X. gardneri </it>(<it>Xg</it>) strain 101 (ATCC 19865). The genomes were compared with each other and with the previously sequenced <it>Xcv </it>strain 85-10. In addition, the molecular features were predicted that may be required for pathogenicity including the type III secretion apparatus, type III effectors, other secretion systems, quorum sensing systems, adhesins, extracellular polysaccharide, and lipopolysaccharide determinants. Several novel type III effectors from <it>Xg </it>strain 101 and <it>Xv </it>strain 1111 genomes were computationally identified and their translocation was validated using a reporter gene assay. A homolog to Ax21, the elicitor of XA21-mediated resistance in rice, and a functional Ax21 sulfation system were identified in <it>Xcv</it>. Genes encoding proteins with functions mediated by type II and type IV secretion systems have also been compared, including enzymes involved in cell wall deconstruction, as contributors to pathogenicity.</p> <p>Conclusions</p> <p>Comparative genomic analyses revealed considerable diversity among bacterial spot pathogens, providing new insights into differences and similarities that may explain the diverse nature of these strains. Genes specific to pepper pathogens, such as the O-antigen of the lipopolysaccharide cluster, and genes unique to individual strains, such as novel type III effectors and bacteriocin genes, have been identified providing new clues for our understanding of pathogen virulence, aggressiveness, and host preference. These analyses will aid in efforts towards breeding for broad and durable resistance in economically important tomato and pepper cultivars.</p

FATORES ASSOCIADOS À APTIDÃO CARDIORRESPIRATÓRIA DE ESCOLARES

RESUMO Introdução: Há alta prevalência de jovens que não atendem ao critério de saúde para aptidão cardior- respiratória, o que os expõe a riscos relacionados à saúde metabólica, cardiovascular e mental. Dessa forma, é relevante investigar quais aspectos estão associados à aptidão cardiorrespiratória de jovens. Objetivo: Analisar os fatores associados à aptidão cardiorrespiratória em escolares. Métodos: Estudo transversal que envolveu 736 escolares (50,1% do sexo feminino) com idade entre 10 a 18 anos. Foram analisadas a condição socioeconômica, escolaridade paterna, número de irmãos, percepção de atividade física, atividade física moderada a vigorosa, participação nas aulas de educação física, prática esportiva, local para prática, transporte ativo e comportamento sedentário. Foram coletadas medidas de estatura, massa corporal e realizado um teste de aptidão cardiorrespiratória. Para estimar a razão de prevalência (RP) e os intervalos de confiança de 95% foi utilizada a regressão de Poisson. Resultados: Para escolares com idade inferior a 14 anos, as variáveis que apresentaram associação com a aptidão cardiorrespiratória foram o sexo feminino (RP = 0,79, 0,68-0,91), sobrepeso (RP = 0,73, 0,61-0,89), percepção de atividade física igual às pessoas de mesma idade (RP = 1,26, 1,03-1,53), atividade física semanal de 3-6h (RP = 1,21, 1,05-1,38), participação nas aulas de educação física (RP = 1,35, 1,03-1,76) e comportamento sedentário ≥ 2h (RP = 0,82, 0,73-0,94). Com relação aos escolares com idade igual ou superior a 14 anos, o sexo feminino (RP = 0,35, 0,19-0,63), o sobrepeso (RP = 0,25, 0,09-0,66), praticar esportes algumas vezes (RP = 1,96, 1,00-3,81) e frequentemente (RP = 2,09, 1,01-4,31) apresentaram associação com a aptidão cardiorrespiratória. Conclusão: Programas de intervenção com o objetivo de aumentar o atendimento ao critério de saúde para aptidão cardiorrespiratória de escolares devem promover a prática de atividade física moderada a vigorosa, prática esportiva, participação nas aulas de educação física e redução do sobrepeso

Pesquisa em educação médica conduzida por estudantes: um ano de experiência do núcleo acadêmico de pesquisa em educação Médica

A pesquisa em educação médica vem se desenvolvendo muito nos últimos anos. A participação de estudantes nos processos de mudanças curriculares também é crescente e bastante contributiva. Ainda, a iniciação científica está sendo amplamente defendida por seu impacto positivo na formação profissional. Relatamos um ano de experiência do Núcleo Acadêmico de Pesquisa em Educação Médica (Napem), que integra as propostas de participação discente nas discussões de ensino médico através de trabalhos de iniciação científica em educação médica. O Napem foi fundado em 2008 e foi bem aceito na comunidade acadêmica da Faculdade de Medicina de Botucatu/Universidade Estadual Paulista (FMB/Unesp). Seus projetos de pesquisa atuais investigam: avaliação do curso médico, avaliação do estudante, fatores que influenciam a busca por iniciação científica, Ligas Acadêmicas e interdisciplinaridade. Estão envolvidos 17 estudantes e dez professores. Em um ano, o Napem apresentou trabalhos em congressos, publicou artigo em periódico indexado e está certificado como grupo de pesquisa no CNPq. Dentre seus desafios estão a necessidade de contínua renovação dos estudantes e o avanço nas pesquisas, de modo que os projetos não se encerrem em si mesmos, mas constituam um continuum de investigação à medida que novas informações sejam agregadas ao conhecimento

Dynamics of Disks and Warps

This chapter reviews theoretical work on the stellar dynamics of galaxy disks. All the known collective global instabilities are identified, and their mechanisms described in terms of local wave mechanics. A detailed discussion of warps and other bending waves is also given. The structure of bars in galaxies, and their effect on galaxy evolution, is now reasonably well understood, but there is still no convincing explanation for their origin and frequency. Spiral patterns have long presented a special challenge, and ideas and recent developments are reviewed. Other topics include scattering of disk stars and the survival of thin disks.Comment: Chapter accepted to appear in Planets, Stars and Stellar Systems, vol 5, ed G. Gilmore. 32 pages, 17 figures. Includes minor corrections made in proofs. Uses emulateapj.st