Integrating the inputs that shape pancreatic islet hormone release.

The pancreatic islet is a complex mini organ composed of a variety of endocrine cells and their support cells, which together tightly control blood glucose homeostasis. Changes in glucose concentration are commonly regarded as the chief signal controlling insulin-secreting beta cells, glucagon-secreting alpha cells and somatostatin-secreting delta cells. However, each of these cell types is highly responsive to a multitude of endocrine, paracrine, nutritional and neural inputs, which collectively shape the final endocrine output of the islet. Here, we review the principal inputs for each islet-cell type and the physiological circumstances in which these signals arise, through the prism of the insights generated by the transcriptomes of each of the major endocrine-cell types. A comprehensive integration of the factors that influence blood glucose homeostasis is essential to successfully improve therapeutic strategies for better diabetes management

The conundrum of conservation agriculture and livelihoods in Southern Africa

Low crop productivity, food insecurity, hunger and malnutrition; inadequate farming knowledge and skills, implements and inputs are characteristic of smallholder agriculture in Southern Africa. Many researchers argue that conservation agriculture can guarantee higher crop productivity, food security, improved livelihoods and environmental protection, better than the unsustainable traditional systems of slash and burn practices. In this paper, we present the results of a meta-analysis of over 40 academic publications to review conservation agriculture’s role in influencing desired livelihood outcomes in Southern Africa. We conclude that the effectiveness of conservation agriculture towards better livelihood outcomes in Southern Africa remains debatable, especially when supportive government policies are lacking

Wat doet een beek zelf na een project van beekherstel?

Al 25 jaar voeren waterbeheerders projecten uit waarbij laglandbeken een kronkelende loop terugkrijgen. Maar wat gebeurt er precies met de vorm van zo'n beek na uitvoering van het project? Hoe lang duurt de aanpassingsperiode en welke factoren hebben invloed? De conclusies van een onderzoek in de Lunterse Beek

CXCL8 Chemokines in Teleost Fish: Two Lineages with Distinct Expression Profiles during Early Phases of Inflammation

Contains fulltext : 126584.pdf (publisher's version ) (Open Access

Evolution of Th2 responses : Characterization of IL-4/13 in sea bass (Dicentrarchus labrax L.) and studies of expression and biological activity

Acknowledgements This research was funded by the European Commission under the 7th Framework Programme for Research and Technological Development (FP7) of the European Union (Grant Agreement 311993 TARGETFISH). T.W. received funding from the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland). MASTS is funded by the Scottish Funding Council (grant reference number HR09011) and contributing institutions.Peer reviewedPublisher PD

Levantamento do uso e cobertura da terra de seis áreas amostrais relacionadas ao Projeto BiosBrasil (Conservation and Sustainable Management of Below-Ground Biodiversity: phase I), Município de Benjamin Constant (AM).

O presente trabalho tem como objetivo identificar o uso e a cobertura da terra e sua distribuição espacial, utilizando técnicas de sensoriamento remoto, em seis áreas selecionadas para o estudo da biodiversidade do solo, reunir informações sobre a história do uso nas áreas amostradas e identificar a intensidade do uso da terra. Ele integra o projeto de pesquisa "Conservation and Sustainable Management of Below-Ground Biodiversity: Phase I" desenvolvido em sete países, financiado pelo Global Environment Facility (GEF) e implementado pelo United Nations Environment Programme (UNEP). A área de estudo no Brasil está localizada na Amazônia Ocidental, no município de Benjamin Constant, estado do Amazonas, e inclui seis áreas amostrais. As classes predominantes de uso e cobertura da terra são: floresta, floresta secundária, agrofloresta, agricultura e pastagem. Há três sistemas, os quais se baseiam predominantemente em a) produtos florestais, b) culturas anuais e c) produtos animais. As práticas culturais empregadas são muito similares em cada um dos três sistemas identificados, indicando não haver diferenças acentuadas em termos de intensidade de uso em cada sistema. Em todos eles não são utilizados corretivos, fertilizantes ou produtos para controle de pragas e doenças, bem como irrigação. Os pontos amostrais classificados como agricultura diferem em relação às espécies cultivadas e histórico de uso, incluindo os períodos de pousio. Nos pontos amostrais sob sistema em que predominam culturas anuais, são mais freqüentes os pousios curtos a longos, com valores de R calculados entre 16,67 e 50,00. Somente um ponto amostral encontra-se sob sistema de cultura permanente, correspondendo a 5,6% de todos os pontos sob agricultura. Os pontos de agrofloresta apresentam diversidade no número de indivíduos e de espécies úteis.bitstream/CNPS-2010/14919/1/bpd71-2005-usocobertseisareasamostrais.pd

Insufficiency of Janus Kinase 2–Autonomous Leptin Receptor Signals for Most Physiologic Leptin Actions

OBJECTIVE: Leptin acts via its receptor (LepRb) to signal the status of body energy stores. Leptin binding to LepRb initiates signaling by activating the associated Janus kinase 2 (Jak2) tyrosine kinase, which promotes the phosphorylation of tyrosine residues on the intracellular tail of LepRb. Two previously examined LepRb phosphorylation sites mediate several, but not all, aspects of leptin action, leading us to hypothesize that Jak2 signaling might contribute to leptin action independently of LepRb phosphorylation sites. We therefore determined the potential role in leptin action for signals that are activated by Jak2 independently of LepRb phosphorylation (Jak2-autonomous signals). RESEARCH DESIGN AND METHODS: We inserted sequences encoding a truncated LepRb mutant (LepRb$^{\Delta65c}$, which activates Jak2 normally, but is devoid of other LepRb intracellular sequences) into the mouse Lepr locus. We examined the leptin-regulated physiology of the resulting $\Delta/\Delta$ mice relative to LepRb-deficient $db/db$ animals. RESULTS: The $\Delta/\Delta$ animals were similar to $db/db$ animals in terms of energy homeostasis, neuroendocrine and immune function, and regulation of the hypothalamic arcuate nucleus, but demonstrated modest improvements in glucose homeostasis. CONCLUSIONS: The ability of Jak2-autonomous LepRb signals to modulate glucose homeostasis in $\Delta/\Delta$ animals suggests a role for these signals in leptin action. Because Jak2-autonomous LepRb signals fail to mediate most leptin action, however, signals from other LepRb intracellular sequences predominate

Identification of new participants in the rainbow trout (Oncorhynchus mykiss) oocyte maturation and ovulation processes using cDNA microarrays

BACKGROUND: The hormonal control of oocyte maturation and ovulation as well as the molecular mechanisms of nuclear maturation have been thoroughly studied in fish. In contrast, the other molecular events occurring in the ovary during post-vitellogenesis have received far less attention. METHODS: Nylon microarrays displaying 9152 rainbow trout cDNAs were hybridized using RNA samples originating from ovarian tissue collected during late vitellogenesis, post-vitellogenesis and oocyte maturation. Differentially expressed genes were identified using a statistical analysis. A supervised clustering analysis was performed using only differentially expressed genes in order to identify gene clusters exhibiting similar expression profiles. In addition, specific genes were selected and their preovulatory ovarian expression was analyzed using real-time PCR. RESULTS: From the statistical analysis, 310 differentially expressed genes were identified. Among those genes, 90 were up-regulated at the time of oocyte maturation while 220 exhibited an opposite pattern. After clustering analysis, 90 clones belonging to 3 gene clusters exhibiting the most remarkable expression patterns were kept for further analysis. Using real-time PCR analysis, we observed a strong up-regulation of ion and water transport genes such as aquaporin 4 (aqp4) and pendrin (slc26). In addition, a dramatic up-regulation of vasotocin (avt) gene was observed. Furthermore, angiotensin-converting-enzyme 2 (ace2), coagulation factor V (cf5), adam 22, and the chemokine cxcl14 genes exhibited a sharp up-regulation at the time of oocyte maturation. Finally, ovarian aromatase (cyp19a1) exhibited a dramatic down-regulation over the post-vitellogenic period while a down-regulation of Cytidine monophosphate-N-acetylneuraminic acid hydroxylase (cmah) was observed at the time of oocyte maturation. CONCLUSION: We showed the over or under expression of more that 300 genes, most of them being previously unstudied or unknown in the fish preovulatory ovary. Our data confirmed the down-regulation of estrogen synthesis genes during the preovulatory period. In addition, the strong up-regulation of aqp4 and slc26 genes prior to ovulation suggests their participation in the oocyte hydration process occurring at that time. Furthermore, among the most up-regulated clones, several genes such as cxcl14, ace2, adam22, cf5 have pro-inflammatory, vasodilatory, proteolytics and coagulatory functions. The identity and expression patterns of those genes support the theory comparing ovulation to an inflammatory-like reaction