Contenido de minerales en algunas especies forrajeras presentes en el pastizal natural de un sistema silvopastoril en el bajo delta del Río Paraná

We analyzed the content of phosphorus (P), calcium (Ca), magnesium (Mg), total ash (Cen) and insoluble ash (Insol), iron (Fe), copper (Cu) and zinc (Zn) in forage species growing wild in silvopastoral system of the Lower Delta of the Parana River after planting forest. 10 plants were harvested from the following species: Glyceria multiflora (Cebadilla de agua), Deyeuxia viridiflavescens (Pasto plateado), Melilotus officinalis (Trébol de olor amarillo), Phalaris angusta (Alpistillo), Lolium multiflorum (Ray gras), Lathyrus pubescens (Arvejilla), Vicia gramínea (Vicia) y Leersia hexandra (Arrocillo). They were dried, incinerated and ashes dissolved in acid. Mineral determinations were performed by atomic absorption spectrophotometry (AAS) and colorimetry. Mineral contents in the species studied here were lower than values informed previously of forage species of temperate weather and, in some cases, mineral requirements for cattle.Se realizó el análisis del contenido de fósforo (P), calcio (Ca), magnesio (Mg), hierro (Fe), cobre (Cu), zinc (Zn) y cenizas totales (Cen) e insolubles (Insol), en especies forrajeras que crecen naturalmente en el sistema silvopastoril del Bajo Delta del Río Paraná,  luego de la plantación forestal. Se cosecharon 10 plantas de cada una de las siguientesespecies: Glyceria multiflora (Cebadilla de agua), Deyeuxia viridiflavescens (Pasto plateado), Melilotus officinalis (Trébol de olor amarillo), Phalaris angusta (Alpistillo), Lolium multiflorum (Ray gras), Lathyrus pubescens (Arvejilla), Vicia gramínea (Vicia) y Leersia hexandra (Arrocillo). Se secaron y calcinaron, resuspendiendo las cenizas en ácido. Las determinaciones de minerales se realizaron por espectrofotometría de absorción atómica (EAA) y colorimetría. Las concentraciones determinadas fueron inferiores a las informadas para forrajeras de clima templado y, en algunos casos, a los requerimientos establecidos para ganado bovino

The impact of low erythrocyte density in human blood on the fitness and energetic reserves of the African malaria vector Anopheles gambiae

Background Anaemia is a common health problem in the developing world. This condition is characterized by a reduction in erythrocyte density, primarily from malnutrition and/or infectious diseases such as malaria. As red blood cells are the primary source of protein for haematophagous mosquitoes, any reduction could impede the ability of mosquito vectors to transmit malaria by influencing their fitness or that of the parasites they transmit. The aim of this study was to determine the impact of differences in the density of red blood cells in human blood on malaria vector (Anopheles gambiae sensu stricto) fitness. The hypotheses tested are that mosquito vector energetic reserves and fitness are negatively influenced by reductions in the red cell density of host human blood meals commensurate with those expected from severe anaemia. Methods Mosquitoes (An. gambiae s.s.) were offered blood meals of different packed cell volume(PCV) of human blood consistent with those arising from severe anaemia (15%) and normalPCV (50%). Associations between mosquito energetic reserves (lipid, glucose and glycogen)and fitness measures (reproduction and survival) and blood meal PCV were investigated. Results The amount of protein that malaria vectors acquired from blood feeding (indexed by haematin excretion) was significantly reduced at low blood PCV. However, mosquitoes feeding on blood of low PCV had the same oviposition rates as those feeding on blood of normal PCV, and showed an increase in egg production of around 15%. The long-term survival of An. gambiae s.s was reduced after feeding on low PCV blood, but PCV had no significant impact on the proportion of mosquitoes surviving through the minimal period required to develop and transmit malaria parasites (estimated as 14 days post-blood feeding). The impact of blood PCV on the energetic reserves of mosquitoes was relatively minor. Conclusions These results suggest that feeding on human hosts whose PCV has been depleted due to severe anaemia does not significantly reduce the fitness or transmission potential of malaria vectors, and indicates that mosquitoes may be able exploit resources for reproduction more efficiently from blood of low rather than normal PCV

Структура вірусних діарей у дітей на Сумщині

Гострі кишкові інфекції (ГКІ) стійко посідають одне з провідних місць серед усіх інфекційних захворювань, характеризуються широкою поширеністю, високою частотою розвитку тяжких форм і ускладнень. Прогрес у галузі лабораторних методів діагностики дозволив істотно розширити уявлення про етіологічні чинники хвороби: у країнах, що розвиваються, домінують діарейні інфекції бактерійної етіології, а в економічно розвинених країнах - вірусної. При цитуванні документа, використовуйте посилання http://essuir.sumdu.edu.ua/handle/123456789/3228

Lifespan extension without fertility reduction following dietary addition of the autophagy activator Torin1 in Drosophila melanogaster

Autophagy is a highly conserved mechanism for cellular repair that becomes progressively down-regulated during normal ageing. Hence, manipulations that activate autophagy could increase lifespan. Previous reports show that manipulations to the autophagy pathway can result in longevity extension in yeast, flies, worms and mammals. Under standard nutrition, autophagy is inhibited by the nutrient sensing kinase Target of Rapamycin (TOR). Therefore, manipulations of TOR that increase autophagy may offer a mechanism for extending lifespan. Ideally, such manipulations should be specific and minimise off-target effects, and it is important to discover additional methods for ‘clean’ lifespan manipulation. Here we report an initial study into the effect of up-regulating autophagy on lifespan and fertility in Drosophila melanogaster by dietary addition of Torin1. Activation of autophagy using this selective TOR inhibitor was associated with significantly increased lifespan in both sexes. Torin1 induced a dose-dependent increase in lifespan in once-mated females. There was no evidence of a trade-off between longevity and fecundity or fertility. Torin1-fed females exhibited significantly elevated fecundity, but also elevated egg infertility, resulting in no net change in overall fertility. This supports the idea that lifespan can be extended without trade-offs in fertility and suggest that Torin1 may be a useful tool with which to pursue anti-ageing research

Accessory gland as a site for prothoracicotropic hormone controlled ecdysone synthesis in adult male insects

Insect steroid hormones (ecdysteroids) are important for female reproduction in many insect species and are required for the initiation and coordination of vital developmental processes. Ecdysteroids are also important for adult male physiology and behavior, but their exact function and site of synthesis remains unclear, although previous studies suggest that the reproductive system may be their source. We have examined expression profiles of the ecdysteroidogenic Halloween genes, during development and in adults of the flour beetle Tribolium castaneum. Genes required for the biosynthesis of ecdysone (E), the precursor of the molting hormone 20-hydroxyecdysone (20E), are expressed in the tubular accessory glands (TAGs) of adult males. In contrast, expression of the gene encoding the enzyme mediating 20E synthesis was detected in the ovaries of females. Further, Spookiest (Spot), an enzyme presumably required for endowing tissues with competence to produce ecdysteroids, is male specific and predominantly expressed in the TAGs. We also show that prothoracicotropic hormone (PTTH), a regulator of E synthesis during larval development, regulates ecdysteroid levels in the adult stage in Drosophila melanogaster and the gene for its receptor Torso seems to be expressed specifically in the accessory glands of males. The composite results suggest strongly that the accessory glands of adult male insects are the main source of E, but not 20E. The finding of a possible male-specific source of E raises the possibility that E and 20E have sex-specific roles analogous to the vertebrate sex steroids, where males produce primarily testosterone, the precursor of estradiol. Furthermore this study provides the first evidence that PTTH regulates ecdysteroid synthesis in the adult stage and could explain the original finding that some adult insects are a rich source of PTTH

New physiological activities of myosuppressin, sulfakinin and NVP-like peptide in Zophobas atratus beetle

Three neuropeptides Zopat-MS-2 (pEDVDHVFLRFa), Zopat-SK-1 (pETSDDYGHLRFa) and Zopat-NVPL-4trunc. (GRWGGFA), recently isolated from the neuroendocrine system of the Zophobas atratus beetle, were tested for their myotropic and hyperglycaemic activities in this species. These peptides exerted differentiated dose-dependent and tissue specific physiological effects. Zopat-MS-2 inhibited contractions of the isolated heart, ejaculatory duct, oviduct and hindgut of adult beetles and induced bimodal effects in the heart contractile activity of pupae in vivo. It also increased the haemolymph free sugar level in larvae of this species, apart from myotropic activity. Zopat-SK-1 showed myostimulatory action on the isolated hindgut of the adult beetles, but it decreased contractions of the heart, ejaculatory duct and oviduct. Injections of this peptide at a dose of 2 μg also caused delayed cardioinhibitory effects on the heartbeat of the pupae. Together with the ability to increase free sugar level in the haemolymph of larvae these were new physiological activities of sulfakinins in insects. Zopat-NVPL-4trunc. inhibited the muscle contractions of the two organs: hindgut and ejaculatory duct but it was inactive on the oviduct and the heart of the adult beetles. This peptide also increased free sugar level concentration in the haemolymph of Z. atratus larvae. These physiological actions are the first biological activities discovered for this group of the insect peptides. The present work showed pleiotropic activity of three neuropeptides and indicates that the visceral muscle contractions and the haemolymph sugar homeostasis in Z. atratus are regulated by complex mechanisms

The main actors involved in parasitization of Heliothis virescens larva

At the moment of parasitization by another insect, the host Heliothis larva is able to defend itself by the activation of humoral and cellular defenses characterized by unusual reactions of hemocytes in response to external stimuli. Here, we have combined light and electron microscopy, staining reactions, and immunocytochemical characterization to analyze the activation and deactivation of one of the most important immune responses involved in invertebrates defense, i.e., melanin production and deposition. The insect host/parasitoid system is a good model to study these events. The activated granulocytes of the host insect are a major repository of amyloid fibrils forming a lattice in the cell. Subsequently, the exocytosed amyloid lattice constitutes the template for melanin deposition in the hemocel. Furthermore, cross-talk between immune and neuroendocrine systems mediated by hormones, cytokines, and neuromodulators with the activation of stress-sensoring circuits to produce and release molecules such as adrenocorticotropin hormone, alpha melanocyte-stimulating hormone, and neutral endopeptidase occurs. Thus, parasitization promotes massive morphological and physiological modifications in the host insect hemocytes and mimics general stress conditions in which phenomena such as amyloid fibril formation, melanin polymerization, pro-inflammatory cytokine production, and activation of the adrenocorticotropin hormone system occur. These events observed in invertebrates are also reported in the literature for vertebrates, suggesting that this network of mechanisms and responses is maintained throughout evolution

Assessment and validation of a suite of reverse transcription-quantitative PCR reference genes for analyses of density-dependent behavioural plasticity in the Australian plague locust

<p>Abstract</p> <p>Background</p> <p>The Australian plague locust, <it>Chortoicetes terminifera</it>, is among the most promising species to unravel the suites of genes underling the density-dependent shift from shy and cryptic solitarious behaviour to the highly active and aggregating gregarious behaviour that is characteristic of locusts. This is because it lacks many of the major phenotypic changes in colour and morphology that accompany phase change in other locust species. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) is the most sensitive method available for determining changes in gene expression. However, to accurately monitor the expression of target genes, it is essential to select an appropriate normalization strategy to control for non-specific variation between samples. Here we identify eight potential reference genes and examine their expression stability at different rearing density treatments in neural tissue of the Australian plague locust.</p> <p>Results</p> <p>Taking advantage of the new orthologous DNA sequences available in locusts, we developed primers for genes encoding 18SrRNA, ribosomal protein L32 (RpL32), armadillo (Arm), actin 5C (Actin), succinate dehydrogenase (SDHa), glyceraldehyde-3P-dehydrogenase (GAPDH), elongation factor 1 alpha (EF1a) and annexin IX (AnnIX). The relative transcription levels of these eight genes were then analyzed in three treatment groups differing in rearing density (isolated, short- and long-term crowded), each made up of five pools of four neural tissue samples from 5^thinstar nymphs. SDHa and GAPDH, which are both involved in metabolic pathways, were identified as the least stable in expression levels, challenging their usefulness in normalization. Based on calculations performed with the geNorm and NormFinder programs, the best combination of two genes for normalization of gene expression data following crowding in the Australian plague locust was EF1a and Arm. We applied their use to studying a target gene that encodes a Ca²⁺binding glycoprotein, <it>SPARC</it>, which was previously found to be up-regulated in brains of gregarious desert locusts, <it>Schistocerca gregaria</it>. Interestingly, expression of this gene did not vary with rearing density in the same way in brains of the two locust species. Unlike <it>S. gregaria</it>, there was no effect of any crowding treatment in the Australian plague locust.</p> <p>Conclusion</p> <p>Arm and EF1a is the most stably expressed combination of two reference genes of the eight examined for reliable normalization of RT-qPCR assays studying density-dependent behavioural change in the Australian plague locust. Such normalization allowed us to show that <it>C. terminifera </it>crowding did not change the neuronal expression of the <it>SPARC </it>gene, a gregarious phase-specific gene identified in brains of the desert locust, <it>S. gregaria</it>. Such comparative results on density-dependent gene regulation provide insights into the evolution of gregarious behaviour and mass migration of locusts. The eight identified genes we evaluated are also candidates as normalization genes for use in experiments involving other Oedipodinae species, but the rank order of gene stability must necessarily be determined on a case-by-case basis.</p