Genomic analysis of two phlebotomine sand fly vectors of Leishmania from the New and Old World.

Phlebotomine sand flies are of global significance as important vectors of human disease, transmitting bacterial, viral, and protozoan pathogens, including the kinetoplastid parasites of the genus Leishmania, the causative agents of devastating diseases collectively termed leishmaniasis. More than 40 pathogenic Leishmania species are transmitted to humans by approximately 35 sand fly species in 98 countries with hundreds of millions of people at risk around the world. No approved efficacious vaccine exists for leishmaniasis and available therapeutic drugs are either toxic and/or expensive, or the parasites are becoming resistant to the more recently developed drugs. Therefore, sand fly and/or reservoir control are currently the most effective strategies to break transmission. To better understand the biology of sand flies, including the mechanisms involved in their vectorial capacity, insecticide resistance, and population structures we sequenced the genomes of two geographically widespread and important sand fly vector species: Phlebotomus papatasi, a vector of Leishmania parasites that cause cutaneous leishmaniasis, (distributed in Europe, the Middle East and North Africa) and Lutzomyia longipalpis, a vector of Leishmania parasites that cause visceral leishmaniasis (distributed across Central and South America). We categorized and curated genes involved in processes important to their roles as disease vectors, including chemosensation, blood feeding, circadian rhythm, immunity, and detoxification, as well as mobile genetic elements. We also defined gene orthology and observed micro-synteny among the genomes. Finally, we present the genetic diversity and population structure of these species in their respective geographical areas. These genomes will be a foundation on which to base future efforts to prevent vector-borne transmission of Leishmania parasites

Immunity in a variable world

Immune function is likely to be a critical determinant of an organism's fitness, yet most natural animal and plant populations exhibit tremendous genetic variation for immune traits. Accumulating evidence suggests that environmental heterogeneity may retard the long-term efficiency of natural selection and even maintain polymorphism, provided alternative host genotypes are favoured under different environmental conditions. ‘Environment’ in this context refers to abiotic factors such as ambient temperature or availability of nutrient resources, genetic diversity of pathogens or competing physiological demands on the host. These factors are generally controlled in laboratory experiments measuring immune performance, but variation in them is likely to be very important in the evolution of resistance to infection. Here, we review some of the literature emphasizing the complexity of natural selection on immunity. Our aim is to describe how environmental and genetic heterogeneities, often excluded from experimentation as ‘noise’, may determine the evolutionary potential of populations or the potential for interacting species to coevolve

Fontes de carboidratos e ionóforo em dietas contendo óleo vegetal para ovinos: digestibilidade, balanço de nitrogênio e fluxo portal de nutrientes Carbohydrate sources and ionophore in sheep diets with vegetal oil: digestibility, nitrogen balance and portal flux of nutrients

Os objetivos neste trabalho foram avaliar a utilização de duas fontes de carboidratos (casca de soja e milho), com a utilização ou não de monensina em dietas com alta densidade lipídica, e seus efeitos sobre a digestibilidade dos nutrientes, o balanço de nitrogênio e o fluxo portal de nutrientes em ovinos. Adotou-se o método de coleta total de fezes e urina para determinação da digestibilidade e do balanço de nitrogênio. O fluxo líquido de nutrientes foi calculado pelo princípio de Fick. Foram utilizados quatro ovinos (54 kg de PV) da raça Corriedale com três cateteres implantados (veia e artéria mesentérica e veia porta). A ingestão, a excreção fecal, a digestão e a digestibilidade de MS, MO e EE não foram influenciadas pelos tratamentos. A ingestão, a digestão e a digestibilidade da FDN foram maiores para as dietas com casca de soja (757,0; 531,1 g/dia e 70,2%) que para aquelas com milho (392,3; 199,9 g/dia e 51,0%), enquanto a dos carboidratos não-fibrosos (CNF), foram maiores para as dietas com milho (474,6, 416,8 g/dia e 87,8%) que para aquelas com casca de soja (148,0; 97,8 g/dia e 66,1%). A concentração de energia expressa como NDT foi maior nas dietas com milho (80,2%) que naquelas com casca de soja (76,7%). Não houve efeito da utilização da monensina nos parâmetros de digestibilidade e balanço de nitrogênio. A excreção fecal da proteína foi menor e a digestibilidade maior para as dietas com milho. A concentração portal e arterial de nitrogênio alfa amino (N alfa-amino) foi menor para as dietas com monensina (3,161 e 2,922 e 3,530 e 3,218 mM, respectivamente). A concentração portal (0,419 vs 0,516 mM), a diferença venosa-arterial (0,230 vs 0,317 mM) e o fluxo portal de amônia (26,119 vs 37,041 mM/h) foram menores para as dietas com milho.<br>The objectives of this trial were to evaluate the effects of two carbohydrate sources (soybean hulls and corn grain) with and without monensin on digestibility, nitrogen balance and portal nutrient flux in sheep fed high vegetable oil diets. Four Corriedale wethers averaging 54 kg of body weight and fitted with catheters in the mesenteric and portal veins and also in the mesenteric artery were used. Digestibility and nitrogen balance were determined using total collection of feces and urine. Net nutrient flux was calculated using the Fick principle. Intake, fecal excretion, digestion and digestibility of dry matter (DM), organic matter (OM) and ether extract (EE) were not affected by treatments. However, intake, digestion and digestibility of neutral detergent fiber (NDF) were higher when animals were fed soybean hulls (757.0 g/d, 531.1 g/d and 70.2%) rather than corn grain (392.3, 199.9 g/d and 51.0%). Conversely, intake, digestion and digestibility of nonfiber carbohydrates (NFC) as well as TDN content were greater on corn (474.6 g/d, 416.8 g/d, 87.8%, 80.2%) than on soybean hulls diets (148.0 g/d, 97.8 g/d and 66.1%, 76.7%). There was no effect of monensin on nutrient digestibility and nitrogen balance. Fecal excretion of protein was lower and protein digestibility was higher for corn diets. Alpha-amino-nitrogen concentration in arterial and portal plasma was lower for diets supplemented with monensin (3.161 and 2.922 mM) compared to non-supplemented monsesin diets (3.530 and 3.218 mM), respectively. Portal concentration (0.419 vs. 0.516 mM), venous-arterial difference (0.230 vs. 0.317 mM), and portal flux (26.119 vs. 37.041 mM/h) of ammonia were all lower on corn diets