The genetics of ray pattern variation in Caenorhabditis briggsae

BACKGROUND: How does intraspecific variation relate to macroevolutionary change in morphology? This question can be addressed in species in which derived characters are present but not fixed. In rhabditid nematodes, the arrangement of the nine bilateral pairs of peripheral sense organs (rays) in tails of males is often the most highly divergent character between species. The development of ray pattern involves inputs from hometic gene expression patterns, TGFβ signalling, Wnt signalling, and other genetic pathways. In Caenorhabditis briggsae, strain-specific variation in ray pattern has provided an entrée into the evolution of ray pattern. Some strains were fixed for a derived pattern. Other strains were more plastic and exhibited derived and ancestral patterns at equal frequencies. RESULTS: Recombinant inbred lines (RILs) constructed from crosses between the variant C. briggsae AF16 and HK104 strains exhibited a wide range of phenotypes including some that were more extreme than either parental strain. Transgressive segregation was significantly associated with allelic variation in the C. briggsae homolog of abdominal B, Cb-egl-5. At least two genes that affected different elements of ray pattern, ray position and ray fusion, were linked to a second gene, mip-1. Consistent with this, the segregation of ray position and ray fusion phenotypes were only partially correlated in the RILs. CONCLUSIONS: The evolution of ray pattern has involved allelic variation at multiple loci. Some of these loci impact the specification of ray identities and simultaneously affect multiple ray pattern elements. Others impact individual characters and are not constrained by covariance with other ray pattern elements. Among the genetic pathways that may be involved in ray pattern evolution is specification of anteroposterior positional information by homeotic genes

Phylogenomic analysis of vertebrate thrombospondins reveals fish-specific paralogues, ancestral gene relationships and a tetrapod innovation

BACKGROUND: Thrombospondins (TSPs) are evolutionarily-conserved, extracellular, calcium-binding glycoproteins with important roles in cell-extracellular matrix interactions, angiogenesis, synaptogenesis and connective tissue organisation. Five TSPs, designated TSP-1 through TSP-5, are encoded in the human genome. All but one have known roles in acquired or inherited human diseases. To further understand the roles of TSPs in human physiology and pathology, it would be advantageous to extend the repertoire of relevant vertebrate models. In general the zebrafish is proving an excellent model organism for vertebrate biology, therefore we set out to evaluate the status of TSPs in zebrafish and two species of pufferfish. RESULTS: We identified by bioinformatics that three fish species encode larger numbers of TSPs than vertebrates, yet all these sequences group as homologues of TSP-1 to -4. By phylogenomic analysis of neighboring genes, we uncovered that, in fish, a TSP-4-like sequence is encoded from the gene corresponding to the tetrapod TSP-5 gene. Thus, all TSP genes show conservation of synteny between fish and tetrapods. In the human genome, the TSP-1, TSP-3, TSP-4 and TSP-5 genes lie within paralogous regions that provide insight into the ancestral genomic context of vertebrate TSPs. CONCLUSION: A new model for TSP evolution in vertebrates is presented. The TSP-5 protein sequence has evolved rapidly from a TSP-4-like sequence as an innovation in the tetrapod lineage. TSP biology in fish is complicated by the presence of additional lineage- and species-specific TSP paralogues. These novel results give deeper insight into the evolution of TSPs in vertebrates and open new directions for understanding the physiological and pathological roles of TSP-4 and TSP-5 in humans

The Genetics of Ray Pattern Variation in Caenorhabditis briggsae

Background: How does intraspecific variation relate to macroevolutionary change in morphology? This question can be addressed in species in which derived characters are present but not fixed. In rhabditid nematodes, the arrangement of the nine bilateral pairs of peripheral sense organs (rays) in tails of males is often the most highly divergent character between species. The development of ray pattern involves inputs from hometic gene expression patterns, TGFβ signalling, Wnt signalling, and other genetic pathways. In Caenorhabditis briggsae, strain-specific variation in ray pattern has provided an entrée into the evolution of ray pattern. Some strains were fixed for a derived pattern. Other strains were more plastic and exhibited derived and ancestral patterns at equal frequencies. Results: Recombinant inbred lines (RILs) constructed from crosses between the variant C. briggsae AF16 and HK104 strains exhibited a wide range of phenotypes including some that were more extreme than either parental strain. Transgressive segregation was significantly associated with allelic variation in the C. briggsae homolog of abdominal B, Cb-egl-5. At least two genes that affected different elements of ray pattern, ray position and ray fusion, were linked to a second gene, mip-1. Consistent with this, the segregation of ray position and ray fusion phenotypes were only partially correlated in the RILs. Conclusions: The evolution of ray pattern has involved allelic variation at multiple loci. Some of these loci impact the specification of ray identities and simultaneously affect multiple ray pattern elements. Others impact individual characters and are not constrained by covariance with other ray pattern elements. Among the genetic pathways that may be involved in ray pattern evolution is specification of anteroposterior positional information by homeotic genes

A Case of Ruptured Splenic Artery Aneurysm in Pregnancy

Background. Rupture of a splenic artery aneurysm is rare complication of pregnancy that is associated with a significant maternal and fetal mortality. Case. A multiparous female presented in the third trimester with hypotension, tachycardia, and altered mental status. A ruptured splenic artery aneurysm was discovered at the time of laparotomy and cesarean delivery. The patient made a full recovery following resection of the aneurysm. The neonate survived but suffered severe neurologic impairment. Conclusion. The diagnosis of ruptured splenic artery aneurysm should be considered in a pregnant woman presenting with signs of intra-abdominal hemorrhage. Early intervention by a multidisciplinary surgical team is key to preserving the life of the mother and fetus

Serotonin Deficiency Rescues Lactation on Day 1 in Mice Fed a High Fat Diet.

Obesity is an inflammatory state associated with delayed lactogenesis stage II and altered mammary gland morphology. Serotonin mediates inflammation and mammary gland involution. The objective of this study was to determine if a genetic deficiency of tryptophan hydroxylase 1, the rate-limiting enzyme in peripheral serotonin synthesis, would result in an improved ability to lactate in dams fed a high fat diet. Twenty-six female mice were fed a high (HFD) or low fat (LFD) diet throughout pregnancy and lactation. Fourteen mice were genetically deficient for Tph1 (Tph1-/-), and twelve were wild type. Milk yield, pup mortality, and dam weights were recorded and milk samples were collected. On day 10 of lactation, dams were sacrificed and mammary glands were harvested for RT-PCR and histological evaluation. HFD dams weighed more than LFD dams at the onset of lactation. WT HFD dams were unable to lactate on day 1 of lactation and exhibited increased pup mortality relative to all other treatments, including Tph1-/- HFD dams. mRNA expression of immune markers C-X-C motif chemokine 5 and tumor necrosis factor alpha were elevated in WT HFD mammary glands. Mammary gland histology showed a reduced number of alveoli in WT compared to Tph1-/- dams, regardless of diet, and the alveoli of HFD dams were smaller than those of LFD dams. Finally, fatty acid profile in milk was dynamic in both early and peak lactation, with reduced de novo synthesis of fatty acids on day 10 of lactation in the HFD groups. Administration of a HFD to C57BL/6 dams produced an obese phenotype in the mammary gland, which was alleviated by a genetic deficiency of Tph1. Serotonin may modulate the effects of obesity on the mammary gland, potentially contributing to the delayed onset of lactogenesis seen in obese women

Planeta ROODA: inovações no AVA a partir de propostas pedagógicas para o ensino fundamental

Este artigo trata de um ambiente virtual de aprendizagem (AVA), Planeta ROODA, voltado à educação escolar. O objetivo é investigar como professores do ensino fundamental elaboram propostas pedagógicas para o AVA considerando-se princípios teóricos interacionistas como as trocas sociais, o interesse e a atividade do estudante. Um levantamento de artigos demonstrou haver um número escasso de produções científicas envolvendo AVA e ensino fundamental. A metodologia de pesquisa é estudo de caso. Os dados constituem-se de entrevistas com professores e registros de atividades realizadas em um curso de extensão. Como resultados, constata-se, com os cursos, que as funcionalidades do Planeta ROODA podem potencializar a construção de propostas pedagógicas interacionistas. Como exemplo, consideram-se a troca de ideias, o compartilhamento de produções assim como a autoria de textos, desenhos, vídeos e projetos. As entrevistas mostraram que a estrutura tecnológica de escolas públicas é precária, especialmente quanto à disponibilização de internet. Por outro lado, o celular está presente no cotidiano dos estudantes e alguns professores os utilizam em suas práticas. Tal fato corroborou para o desenvolvimento da terceira versão do Planeta ROODA, a qual contará com uma versão para dispositivos móveis

Planet ROODA: innovations in the VLE from pedagogical proposals for elementary education

Este artigo trata de um ambiente virtual de aprendizagem (AVA), Planeta ROODA, voltado à educação escolar. O objetivo é investigar como professores do ensino fundamental elaboram propostas pedagógicas para o AVA considerando-se princípios teóricos interacionistas como as trocas sociais, o interesse e a atividade do estudante. Um levantamento de artigos demonstrou haver um número escasso de produções científicas envolvendo AVA e ensino fundamental. A metodologia de pesquisa é estudo de caso. Os dados constituem-se de entrevistas com professores e registros de atividades realizadas em um curso de extensão. Como resultados, constata-se, com os cursos, que as funcionalidades do Planeta ROODA podem potencializar a construção de propostas pedagógicas interacionistas. Como exemplo, consideram-se a troca de ideias, o compartilhamento de produções assim como a autoria de textos, desenhos, vídeos e projetos. As entrevistas mostraram que a estrutura tecnológica de escolas públicas é precária, especialmente quanto à disponibilização de internet. Por outro lado, o celular está presente no cotidiano dos estudantes e alguns professores os utilizam em suas práticas. Tal fato corroborou para o desenvolvimento da terceira versão do Planeta ROODA, a qual contará com uma versão para dispositivos móveis.This article deals of a virtual learning enviroment (VLE), ROODA Planet, in order to schooling. The objective is to investigate how elementary school teachers elaborate proposals to the VLE considering the interactionist theoretical principles as socials exchanges, the interest and the student activity. An analysis of articles on the subject demonstrate a small number of scientific productions involving the study of VLE in elementary schools. The research methodology is a case study. The datas made up of interviews with teachers and activity logs an extension course with the VLE. As a result, as seen during the extension course, the features of ROODA Planet can increase the construction of interactionist pedagogical proposals. As example, considering sharing of ideias, sharing posts like written texts, drawings, videos and projects. The interviews show that the technological structure of public schools is poor, especially the availability of the internet. On the other hand, the smartphones are widely present in the daily lives of students and teachers, who use in their activities. This fact corroborated for the development of the third version of ROODA Planet, which will feature a mobile version