A Pair of Dopamine Neurons Target the D1-Like Dopamine Receptor DopR in the Central Complex to Promote Ethanol-Stimulated Locomotion in Drosophila

Dopamine is a mediator of the stimulant properties of drugs of abuse, including ethanol, in mammals and in the fruit fly Drosophila. The neural substrates for the stimulant actions of ethanol in flies are not known. We show that a subset of dopamine neurons and their targets, through the action of the D1-like dopamine receptor DopR, promote locomotor activation in response to acute ethanol exposure. A bilateral pair of dopaminergic neurons in the fly brain mediates the enhanced locomotor activity induced by ethanol exposure, and promotes locomotion when directly activated. These neurons project to the central complex ellipsoid body, a structure implicated in regulating motor behaviors. Ellipsoid body neurons are required for ethanol-induced locomotor activity and they express DopR. Elimination of DopR blunts the locomotor activating effects of ethanol, and this behavior can be restored by selective expression of DopR in the ellipsoid body. These data tie the activity of defined dopamine neurons to D1-like DopR-expressing neurons to form a neural circuit that governs acute responding to ethanol

l-Arginine stimulates proliferation and prevents endotoxin-induced death of intestinal cells

This study tested the hypothesis that l-arginine (Arg) may stimulate cell proliferation and prevent lipopolysaccharide (LPS)-induced death of intestinal cells. Intestinal porcine epithelial cells (IPEC-1) were cultured for 4 days in Arg-free Dulbecco’s modified Eagle’s-F12 Ham medium (DMEM-F12) containing 10, 100 or 350 μM Arg and 0 or 20 ng/ml LPS. Cell numbers, protein concentrations, protein synthesis and degradation, as well as mammalian target of rapamycin (mTOR) and Toll-like receptor 4 (TLR4) signaling pathways were determined. Without LPS, IPEC-1 cells exhibited time- and Arg-dependent growth curves. LPS treatment increased cell death and reduced protein concentrations in IPEC-1 cells. Addition of 100 and 350 μM Arg to culture medium dose-dependently attenuated LPS-induced cell death and reduction of protein concentrations, in comparison with the basal medium containing 10 μM Arg. Furthermore, supplementation of 100 and 350 μM Arg increased protein synthesis and reduced protein degradation in both control and LPS-treated IPEC-1 cells. Consistent with the data on cell growth and protein turnover, addition of 100 or 350 μM Arg to culture medium increased relative protein levels for phosphorylated mTOR and phosphorylated ribosomal protein S6 kinase-1, while reducing the relative levels of TLR4 and phosphorylated levels of nuclear factor-κB in LPS-treated IPEC-1 cells. These results demonstrate a protective effect of Arg against LPS-induced enterocyte damage through mechanisms involving mTOR and TLR4 signaling pathways, as well as intracellular protein turnover

Conversion of t11t13 CLA into c9t11 CLA in Caco-2 Cells and Inhibition by Sterculic Oil

Background : Conjugated linoleic acids (CLA), and principally c9t11 CLA, are suspected to have numerous preventive properties regarding non-infectious pathologies such as inflammatory diseases, atherosclerosis and several types of cancer. C9t11 CLA is produced in the rumen during biohydrogenation of linoleic acid, but can also be synthesized in mammalian tissues from trans-vaccenic acid (C18:1 t11) through the action of delta-9 desaturase (D9D). For several years, it is also known that c9t11 CLA can be synthesized from conjugated linolenic acids (CLnA), i.e. c9t11c13 CLnA and c9t11t13 CLnA. This study aimed at investigating to which extent and by which route c9t11 CLA can be produced from another isomer of CLA, the t11t13 CLA that is structurally very similar to c9t11t13 CLnA, in Caco-2 cells

MAP4K3 Is a Component of the TORC1 Signalling Complex that Modulates Cell Growth and Viability in Drosophila melanogaster

Background: MAP4K3 is a conserved Ser/Thr kinase that has being found in connection with several signalling pathways, including the Imd, EGFR, TORC1 and JNK modules, in different organisms and experimental assays. We have analyzed the consequences of changing the levels of MAP4K3 expression in the development of the Drosophila wing, a convenient model system to characterize gene function during epithelial development. Methodology and Principal Findings: Using loss-of-function mutants and over-expression conditions we find that MAP4K3 activity affects cell growth and viability in the Drosophila wing. These requirements are related to the modulation of the TORC1 and JNK signalling pathways, and are best detected when the larvae grow in a medium with low protein concentration (TORC1) or are exposed to irradiation (JNK). We also show that MAP4K3 display strong genetic interactions with different components of the InR/Tor signalling pathway, and can interact directly with the GTPases RagA and RagC and with the multi-domain kinase Tor. Conclusions and Significance: We suggest that MAP4K3 has two independent functions during wing development, one related to the activation of the JNK pathway in response to stress and other in the assembling or activation of the TORC1 complex, being critical to modulate cellular responses to changes in nutrient availability

The Germinal Center Kinase GCK-1 Is a Negative Regulator of MAP Kinase Activation and Apoptosis in the C. elegans Germline

The germinal center kinases (GCK) constitute a large, highly conserved family of proteins that has been implicated in a wide variety of cellular processes including cell growth and proliferation, polarity, migration, and stress responses. Although diverse, these functions have been attributed to an evolutionarily conserved role for GCKs in the activation of ERK, JNK, and p38 MAP kinase pathways. In addition, multiple GCKs from different species promote apoptotic cell death. In contrast to these paradigms, we found that a C. elegans GCK, GCK-1, functions to inhibit MAP kinase activation and apoptosis in the C. elegans germline. In the absence of GCK-1, a specific MAP kinase isoform is ectopically activated and oocytes undergo abnormal development. Moreover, GCK-1- deficient animals display a significant increase in germ cell death. Our results suggest that individual germinal center kinases act in mechanistically distinct ways and that these functions are likely to depend on organ- and developmental-specific contexts

Phylogeny and evolution of life-history strategies in the Sycophaginae non-pollinating fig wasps (Hymenoptera, Chalcidoidea)

<p>Abstract</p> <p>Background</p> <p>Non-pollinating Sycophaginae (Hymenoptera, Chalcidoidea) form small communities within <it>Urostigma </it>and <it>Sycomorus </it>fig trees. The species show differences in galling habits and exhibit apterous, winged or dimorphic males. The large gall inducers oviposit early in syconium development and lay few eggs; the small gall inducers lay more eggs soon after pollination; the ostiolar gall-inducers enter the syconium to oviposit and the cleptoparasites oviposit in galls induced by other fig wasps. The systematics of the group remains unclear and only one phylogeny based on limited sampling has been published to date. Here we present an expanded phylogeny for sycophagine fig wasps including about 1.5 times the number of described species. We sequenced mitochondrial and nuclear markers (4.2 kb) on 73 species and 145 individuals and conducted maximum likelihood and Bayesian phylogenetic analyses. We then used this phylogeny to reconstruct the evolution of Sycophaginae life-history strategies and test if the presence of winged males and small brood size may be correlated.</p> <p>Results</p> <p>The resulting trees are well resolved and strongly supported. With the exception of <it>Apocrytophagus</it>, which is paraphyletic with respect to <it>Sycophaga</it>, all genera are monophyletic. The Sycophaginae are divided into three clades: (i) <it>Eukoebelea</it>; (ii) <it>Pseudidarnes</it>, <it>Anidarnes </it>and <it>Conidarnes </it>and (iii) <it>Apocryptophagus</it>, <it>Sycophaga </it>and <it>Idarnes</it>. The ancestral states for galling habits and male morphology remain ambiguous and our reconstructions show that the two traits are evolutionary labile.</p> <p>Conclusions</p> <p>The three main clades could be considered as tribes and we list some morphological characters that define them. The same biologies re-evolved several times independently, which make Sycophaginae an interesting model to test predictions on what factors will canalize the evolution of a particular biology. The ostiolar gall-inducers are the only monophyletic group. In 15 Myr, they evolved several morphological adaptations to enter the syconia that make them strongly divergent from their sister taxa. Sycophaginae appears to be another example where sexual selection on male mating opportunities favored winged males in species with small broods and wingless males in species with large broods. However, some species are exceptional in that they lay few eggs but exhibit apterous males, which we hypothesize could be due to other selective pressures selecting against the re-appearance of winged morphs.</p

Effect of conjugated linoleic acid supplementation on lipoprotein lipase activity in 3T3-L1 adipocyte culture Efeito da suplementação com ácido linoléico conjugado sobre a atividade da lípase lipoprotéica em cultura de adipócitos 3T3-L1

Supplementation with conjugated linoleic acid may reduce fat body mass and increase lean body mass in various species. Some studies have demonstrated that conjugated linoleic acid reduces body fat, in part, by inhibiting the activity of lipoprotein lipase in adipocytes. The objective of this work was to study the effect of conjugated linoleic acid supplementation on lipoprotein lipase activity in 3T3-L1 adipocyte culture. 3T3-L1 adipocytes received linoleic acid (group C) or conjugated linoleic acid (group AE, supplemented with AdvantEdge® CLA, and group CO, supplemented with CLA One®) in concentrations of 1 mmol/L. Heparin-releasable lipoprotein lipase activity was analyzed by means of a 3T3-L1 adipocyte culture. After 7 days, heparin-releasable lipoprotein lipase activity was lower in the groups AE and CO supplemented with conjugated linoleic acid. These results suggest that one of the mechanisms by which CLA is capable of reducing body fat is by reducing lipoprotein lipase activity.<br>A suplementação com ácido linoléico conjugado pode reduzir a gordura corporal e aumentar a massa magra em diferentes espécies. Alguns estudos têm demonstrado que o ácido linoléico conjugado reduz a gordura corporal, por meio da inibição da atividade de lípase lipoprotéica em adipócitos. O objetivo deste estudo foi avaliar o efeito da suplementação com uma mistura de isômeros do ácido linoléico conjugado sobre a atividade da lípase lipoprotéica em cultura de adipócitos 3T3-L1. Os adipócitos 3T3-L1 receberam ácido linoléico (grupo controle) ou ácido linoléico conjugado (grupo AE, suplementado com AdvantEdge® CLA, e grupo CO, suplementado com CLA One®) na concentração de 1 mmol/L. A atividade de lípase lipoprotéica livre de heparina foi analisada pela média da cultura de adipócitos. Após 7 dias, a atividade da lípase lipoprotéica livre de heparina mostrou menores valores nos grupos AE e CO, suplementados com ácido linoléico conjugado. Estes resultados sugerem que um dos mecanismos pelo qual o ácido linoléico conjugado seja capaz de reduzir a gordura corporal é a partir da redução da atividade da lípase lipoprotéica