Detection of quantitative trait loci for resistance to gastrointestinal nematode infections in Creole goats

This study aimed to identify regions of the genome affecting resistance to gastrointestinal nematodes in a Creole goat population naturally exposed to a mixed nematode infection (Haemonchus contortus, Trichostrongylus colubriformis and Oesophagostomum columbianum) by grazing on irrigated pasture. A genome‐wide quantitative trait loci (QTL) scan was performed on 383 offspring from 12 half‐sib families. A total of 101 microsatellite markers were genotyped. Traits analysed were faecal egg count (FEC), packed cell volume (PCV), eosinophil count and bodyweight (BW) at 7 and 11 months of age. Levels of activity of immunoglobulin A (IgA) and activity of immunoglobulin E (IgE) anti‐Haemonchus contortus L3 crude extracts and adult excretion/secretion products (ESPs) were also analysed. Using interval mapping, this study identified 13 QTL for parasite resistance. Two QTL linked with FEC were found on chromosomes 22 and 26. Three QTL were detected on chromosomes 7, 8 and 14 for eosinophil counts. Three QTL linked with PCV were identified on chromosomes 5, 9 and 21. A QTL for BW at 7 months of age was found on chromosome 6. Lastly, two QTL detected on chromosomes 3 and 10 were associated with IgE anti‐L3, and IgE anti‐ESP was linked with two QTL on chromosomes 1 and 26. This study is the first to have identified regions of the genome linked with nematode resistance in a goat population using a genome scan. These results provide useful tools for the understanding of parasite resistance in small ruminants.     

Nitrogen-fixing cyanobacteria as source of phycobiliprotein pigments. Composition and growth performance of ten filamentous heterocystous strains

Ten strains of filamentous, heterocystous nitrogen-fixing blue-green algae (cyanobacteria) were screened for growth performance and tolerance to temperature, pH, irradiance and salinity, together with their potential as producers of phycobiliprotein pigments. Phycobiliproteins typically accounted for about 50% total cell protein, the prevalent type being C-phycocyanin, followed by alloppycocyanin, with levels of 17 and 11% d.wt, respectively, in some strains of Anabaena and Nostoc. C-phycoerythrin was the major pigment in several Nostoc strains, reaching 10% d.wt. Some strains represent, therefore, excellent sources of one or more phycobiliproteins. All strains tolerated an irradiance of ca 2000 μmol photon m^-2 s^-1. Anabaena sp. ATCC 33047 and Nostoc sp. (Albufera) exhibited the widest optimum range of both temperature (30–45 and 25–40 °C) and pH (6.5–9.5 and 6.0–9.0) for growth, the former also showing significant salt tolerance. In an outdoor open system, productivity of cultures of two phycoerythrin-rich strains of Nostoc was over 20 g (d.wt) m^-2 d^-1 during summer. The growth performance of the allophycocyanin-rich Anabaena sp. ATCC 33047 in outdoor semi-continuous culture has been assessed throughout the year. Productivity values under optimized conditions ranged from 9 (winter) to 24 (summer) g (d.wt) m^-2 d^-1.     

Malaria entomological risk factors in relation to land cover in the Lower Caura River Basin,Venezuela

To explore the effects of deforestation and resulting differences in vegetation and land cover on entomological parameters, such as anopheline species composition, abundance, biting rate, parity and entomological inoculation rate (EIR), three villages were selected in the Lower Caura River Basin, state of Bolívar, Venezuela. All-night mosquito collections were conducted between March 2008-January 2009 using CDC light traps and Mosquito Magnet^(r) Liberty Plus. Human landing catches were performed between 06:00 pm-10:00 pm, when anophelines were most active. Four types of vegetation were identified. The Annual Parasite Index was not correlated with the type of vegetation. The least abundantly forested village had the highest anopheline abundance, biting rate and species diversity. Anopheles darlingi and Anopheles nuneztovari were the most abundant species and were collected in all three villages. Both species showed unique biting cycles. The more abundantly forested village of El Palmar reported the highest EIR. The results confirmed previous observations that the impacts of deforestation and resulting changes in vegetation cover on malaria transmission are complex and vary locally.     

Draft genome sequence of Bizionia argentinensis, isolated from Antarctic surface water

A psychrotolerant marine bacterial strain, designated JUB59(T), was isolated from Antarctic surface seawater and classified as a new species of the genus Bizionia. Here, we present the first draft genome sequence for this genus, which suggests interesting features such as UV resistance, hydrolytic exoenzymes, and nitrogen metabolism.     

Mosquito transgenesis: what is the fitness cost?

The generation of transgenic mosquitoes with a minimal fitness load is a prerequisite for the success of strategies for controlling mosquito-borne diseases using transgenic insects. It is important to assemble as much information as possible on this subject because realistic estimates of transgene fitness costs are essential for modeling and planning release strategies. Transgenic mosquitoes must have minimal fitness costs, because such costs would reduce the effectiveness of the genetic drive mechanisms that are used to introduce the transgenes into field mosquito populations. Several factors affect fitness of transgenic mosquitoes, including the potential negative effect of transgene products and insertional mutagenesis. Studies to assess fitness of transgenic mosquitoes in the field (as opposed to the laboratory) are still needed.     

Prediction of apparent trabecular bone stiffness through fourth-order fabric tensors

The apparent stiffness tensor is an important mechanical parameter for characterizing trabecular bone. Previous studies have modeled this parameter as a function of mechanical properties of the tissue, bone density, and a second-order fabric tensor, which encodes both anisotropy and orientation of trabecular bone. Although these models yield strong correlations between observed and predicted stiffness tensors, there is still space for reducing accuracy errors. In this paper, we propose a model that uses fourth-order instead of second-order fabric tensors. First, the totally symmetric part of the stiffness tensor is assumed proportional to the fourth-order fabric tensor in the logarithmic scale. Second, the asymmetric part of the stiffness tensor is derived from relationships among components of the harmonic tensor decomposition of the stiffness tensor. The mean intercept length (MIL), generalized MIL (GMIL), and fourth-order global structure tensor were computed from images acquired through microcomputed tomography of 264 specimens of the femur. The predicted tensors were compared to the stiffness tensors computed by using the micro-finite element method (\(\upmu \)FE), which was considered as the gold standard, yielding strong correlations (\(R^2\) above 0.962). The GMIL tensor yielded the best results among the tested fabric tensors. The Frobenius error, geodesic error, and the error of the norm were reduced by applying the proposed model by 3.75, 0.07, and 3.16 %, respectively, compared to the model by Zysset and Curnier (Mech Mater 21(4):243–250, 1995) with the second-order MIL tensor. From the results, fourth-order fabric tensors are a good alternative to the more expensive \(\upmu \)FE stiffness predictions.     

Heme Amplifies the Innate Immune Response to Microbial Molecules through Spleen Tyrosine Kinase (Syk)-dependent Reactive Oxygen Species Generation

Infectious diseases that cause hemolysis are among the most threatening human diseases, because of severity and/or global distribution. In these conditions, hemeproteins and heme are released, but whether heme affects the inflammatory response to microorganism molecules remains to be characterized. Here, we show that heme increased the lethality and cytokine secretion induced by LPS in vivo and enhanced the secretion of cytokines by macrophages stimulated with various agonists of innate immune receptors. Activation of nuclear factor κB (NF-κB) and MAPKs and the generation of reactive oxygen species were essential to the increase in cytokine production induced by heme plus LPS. This synergistic effect of heme and LPS was blocked by a selective inhibitor of spleen tyrosine kinase (Syk) and was abrogated in dendritic cells deficient in Syk. Moreover, inhibition of Syk and the downstream molecules PKC and PI3K reduced the reactive oxygen species generation by heme. Our results highlight a mechanism by which heme amplifies the secretion of cytokines triggered by microbial molecule activation and indicates possible pathways for therapeutic intervention during hemolytic infectious diseases.