Bayesian inference of mixed models in quantitative genetics of crop species

The objectives of this study were to implement a Bayesian framework for mixed models analysis in crop species breeding and to exploit alternatives for informative prior elicitation. Bayesian inference for genetic evaluation in annual crop breeding was illustrated with the first two half-sib selection cycles in a popcorn population. The Bayesian framework was based on the Just Another Gibbs Sampler software and the R2jags package. For the first cycle, a non-informative prior for the inverse of the variance components and an informative prior based on meta-analysis were used. For the second cycle, a non-informative prior and an informative prior defined as the posterior from the non-informative and informative analyses of the first cycle were used. Regarding the first cycle, the use of an informative prior from the meta-analysis provided clearly distinct results relative to the analysis with a non-informative prior only for the grain yield. Regarding the second cycle, the results for the expansion volume and grain yield showed differences among the three analyses. The differences between the non-informative and informative prior analyses were restricted to variance components and heritability. The correlations between the predicted breeding values from these analyses were almost perfect.     

A low-protein diet during pregnancy prevents modifications in intercellular communication proteins in rat islets

Background

Gap junctions between β-cells participate in the precise regulation of insulin secretion. Adherens junctions and their associated proteins are required for the formation, function and structural maintenance of gap junctions. Increases in the number of the gap junctions between β-cells and enhanced glucose-stimulated insulin secretion are observed during pregnancy. In contrast, protein restriction produces structural and functional alterations that result in poor insulin secretion in response to glucose. We investigated whether protein restriction during pregnancy affects the expression of mRNA and proteins involved in gap and adherens junctions in pancreatic islets. An isoenergetic low-protein diet (6% protein) was fed to non-pregnant or pregnant rats from day 1–15 of pregnancy, and rats fed an isocaloric normal-protein diet (17% protein) were used as controls.

Results

The low-protein diet reduced the levels of connexin 36 and β-catenin protein in pancreatic islets. In rats fed the control diet, pregnancy increased the levels of phospho-[Ser^279/282]-connexin 43, and it decreased the levels of connexin 36, β-catenin and beta-actin mRNA as well as the levels of connexin 36 and β-catenin protein in islets. The low-protein diet during pregnancy did not alter these mRNA and protein levels, but avoided the increase of levels of phospho-[Ser^279/282]-connexin 43 in islets. Insulin secretion in response to 8.3 mmol/L glucose was higher in pregnant rats than in non-pregnant rats, independently of the nutritional status.

Conclusion

Short-term protein restriction during pregnancy prevented the Cx43 phosphorylation, but this event did not interfer in the insulin secretion.     

Laboratory diagnosis of mange-causing mites in dogs using a modified centrifugation-flotation technique in sucrose solution

Among the skin disorders of dogs, scabies is notable for its high occurrence rate and the need for veterinary interventions. There are two obstacles to making this diagnosis through direct investigation under a microscope (DIM): the continual need to make new slides when the results are negative and the long time needed for reading these slides. Thus, the objective of the present study was to compare efficacy between DIM and the technique of centrifugation-flotation in sucrose solution (CFSS) in samples from dogs in the semiarid region of the state of Paraíba, Brazil. Samples from 136 dogs were used, and three slides were made for each examination (DIM and CFSS). The readings were halted in cases of positivity. Positive samples were obtained from 56.6% of the dogs (77/136), of which 76.6% (59/77) were positive through both techniques, 13% (10/77) only through DIM and 10.4% (8/77) only through CFSS. The positivity rate did not differ statistically between the techniques. CFSS showed higher quality of readings, due to the considerably fewer artifacts on the slides, thereby optimizing the reading time. Sensitivity (85.6%), specificity (88.1%), accuracy (86.8%), positive predictive value (88.1%) and negative predictive value (85.1%) were obtained and the kappa coefficient (0.73) was considered substantial. It was concluded that CFSS showed high diagnostic capacity for scabies, similar to that of DIM, with optimized reading time, fewer artifacts and better display of mites.

     

Drivers of global variation in land ownership

Land ownership shapes natural resource management and social–ecological resilience, but the factors determining ownership norms in human societies remain unclear. Here we conduct a global empirical test of long‐standing theories from ecology, economics and anthropology regarding potential drivers of land ownership and territoriality. Prior theory suggests that resource defensibility, subsistence strategies, population pressure, political complexity and cultural transmission mechanisms may all influence land ownership. We applied multi‐model inference procedures based on logistic regression to cultural and environmental data from 102 societies, 71 with some form of land ownership and 31 with no land ownership. We found an increased probability of land ownership in mountainous environments, where patchy resources may be more cost effective to defend via ownership. We also uncovered support for the role of population pressure, with a greater probability of land ownership in societies living at higher population densities. Our results also show more land ownership when neighboring societies also practiced ownership. We found less support for variables associated with subsistence strategies and political complexity.     

Physiological and molecular analyses of early and late Coffea arabica cultivars at different stages of fruit ripening

Coffee quality is strongly influenced by a great number of factors, among which the fruit ripening stage at harvest time has a major influence on this feature. Studies comprising ethylene production and the regulation of ethylene biosynthesis genes during the ripening process indicate that ethylene plays an important role on coffee fruit ripening. Coffee early cultivars usually show a more uniform ripening process although little is known about the genetic factors that promote the earliness of ripening. Thus, in order to better understand the physiological and genetic factors involved in the regulation of ripening time, and consequently ripening uniformity, this study aimed to analyze ethylene and respiration patterns during coffee ripening, as well as to analyze ACC oxidase, an ethylene biosynthesis enzyme, gene expression, in fruits of early (Catucaí 785-15) and late (Acauã) coffee cultivars. Coffee fruits were harvested monthly from 124 days after flowering (end of February), until complete maturation (end of June). Dry matter, moisture content, color, respiratory rate and ethylene production analysis were performed. In silico analysis identified a coffee ACC oxidase gene (CaACO-like) and its expression was analyzed by real-time PCR. Dry matter and relative water content constantly increased and gradually decreased, respectively, during fruit ripening, and the color analysis enabled the observation of the earliness in the ripening process displayed by Catucaí 785-15 and its higher fruit ripening uniformity. The results obtained from the CaACO-like expression analysis and respiration and ethylene analysis suggest that the differences in ripening behavior between the two coffee cultivars analyzed in this study may be related to the differences in their capacity to produce ethylene, with fruits of Catucaí 785-15 and Acauã showing a typical and an attenuated climacteric phase, respectively, which may have lead to differences in their ripening time and uniformity.     

The hard-tick fauna of mainland Portugal (Acari: Ixodidae): an update on geographical distribution and known associations with hosts and pathogens

This work is an updated revision of the available information on Portuguese ixodid tick species. It includes data on tick biology, ecology, taxonomy and host/pathogen-associations. The current list of Portuguese ixodid ticks comprises twenty species: Dermacentor marginatus (Sulzer, 1776), Dermacentor reticulatus (Fabricius, 1794), Haemaphysalis hispanica Gil Collado, 1938, Haemaphysalis inermis Birula, 1895, Haemaphysalis punctata Canestrini & Fanzago, 1878, Hyalomma lusitanicum Koch, 1844, Hyalomma marginatum Koch, 1844, Ixodes acuminatus Neumann, 1901, Ixodes bivari Dias, 1990, Ixodes canisuga Johnston, 1849, Ixodes frontalis (Panzer, 1798), Ixodes hexagonus Leach, 1815, Ixodes ricinus (Linnaeus, 1758), Ixodes simplex Neumann, 1906, Ixodes ventalloi Gil Collado, 1936, Ixodes vespertilionis Koch, 1844, Rhipicephalus (Boophilus) annulatus (Say, 1821), Rhipicephalus bursa Canestrini & Fanzago, 1878, Rhipicephalus pusillus Gil Collado, 1938, and Rhipicephalus sanguineus (Latreille, 1806).     

Isolation and characterization of cellulolytic bacteria from the Stain house Lake,Antarctica

The main aim was to evaluate the occurrence of cellulolytic bacteria from the Stain house Lake, located at Admiralty Bay, Antarctica. Thick cotton string served as a cellulose bait for the isolation of bacteria. A total of 52 bacterial isolates were recovered and tested for their cellulase activity, and two of them, isolates CMAA 1184 and CMAA 1185, showed significant cellulolytic activity on carboxymethylcellulose agar plates. Phylogenetic analysis placed the isolates into the Bacillus 16S ribosomal RNA gene subclade. Both isolates produced a cold-active cellulase which may play a crucial role in this extreme environment.