Drift across the Atlantic: genetic differentiation and population structure in Brazilian and Portuguese native goat breeds

Brazilian goat breeds are believed to derive mainly from animals brought by Portuguese settlers since the 16th century. We used microsatellite markers in a sample of 436 animals to study genetic variability and differentiation of the six Portuguese (PT) and six Brazilian (BR) goat breeds currently recognized in the two countries. These breeds were also compared with an outgroup represented by a sample of Alpine (ALP) goats. The effective number of alleles and allelic richness were slightly higher in PT than in BR breeds. The global F(ST) was nearly 0.11 when PT and BR breeds were considered, with a mean pairwise F(ST) of about 0.03 among PT breeds, 0.07 among BR breeds and 0.15 between PT and BR breeds. The dendrogram illustrating relationships between populations and the correspondence analysis indicate the existence of two very distinct clusters, corresponding to the countries of origin of the breeds studied, which are nearly equidistant from the Alpine outgroup. The analysis with structure confirmed the separation between PT and BR breeds but suggests that some BR breeds, especially Graúna and Canindé, may share a common ancestry with PT breeds. The divergence observed between PT and BR breeds may result from founder effects and genetic drift but could also reflect the introduction in Brazil of goats originating from other regions, e.g., West Africa.     

Seroprevalence of anti-Leptospira spp. antibodies in dogs in Bahia, Brazil

The aim of this study was to determine the prevalence of anti-Leptospira spp. antibodies in dogs living in the urban area of the city of Ilhéus, Bahia, Brazil using the microscopic agglutination test (MAT) to investigate 24 serovars. A semi-structured questionnaire was administered to dog owners to collect data about demography, husbandry and environmental factors. The prevalence of anti-Leptospira spp. antibodies in the population of 282 dogs was 7.1% (95% confidence interval: 4.4-10.7%). Serovar Copenhageni was the most prevalent, followed by serovars Bratislava, Canicola and Gryppotyphosa. No risk factor was detected with regard to demography (age, gender and breed), husbandry (Leptospira vaccinations, food and water exposure through their environment, hunting habits, contact with other animals and contact with rats) and environmental factors (sewage network, garbage collection, history of flooding, river proximity and wastelands). Despite the low prevalence found in this study, the seroprevalence of Leptospira spp. in healthy dogs in Ilhéus indicates the presence of this agent in the environment, which may be a source of human infection. Knowledge of the serovars present in this environment is important for understanding the epidemiology of leptospirosis and establishing public health policies aimed at its control.     

An atypical biotype I Actinobacillus pleuropneumoniae serotype 13 is present in North America

Atypical Actinobacillus pleuropneumoniae serotype 13 strains present in North America are described here for the first time. Different from serotype 13 strains described in Europe, North America strains are biotype I and antigenically related to both, serotypes 13 and 10. Chemical and structural analysis of the capsular polysaccharide (CPS) and lipopolysaccharide (LPS) of a representative strain revealed that the CPS is almost identical to that of the reference strain of serotype 13, having a slightly higher degree of glycose O-acetylation. However, it produces an O-PS within the LPS antigenically and structurally identical with that of the reference strain of A. pleuropneumoniae serotype 10. The O-PS was characterized as a homopolymer of 1,2 linked β-D-galactofuranosyl residues, a structure unrelated to that of the O-PS produced by the reference strain of serotype 13. Strains from Canada and United States are antigenically, phenotypically and genotypically similar. Animals infected by one of these strains induced antibodies that were detected by a LPS-based ELISA diagnostic test using either the homologous antigen or that of serotype 10. Based on the LPS and toxin profile, these strains might be misidentified as A. pleuropneumoniae serotype 10.     

Farnesol inhibits in vitro growth of the Cryptococcus neoformans species complex with no significant changes in virulence-related exoenzymes

Farnesol is a sesquiterpene alcohol that modulates cell-to-cell communication in Candida albicans. In recent years, several studies have shown that this molecule presents inhibitory effects against non-albicans Candida species, Paracoccidioides brasiliensis and bacteria. The present study aimed at determining the effect of farnesol on the growth of strains of the Cryptococcus neoformans species complex, through microdilution assays. In addition, the effect of farnesol on the synthesis of phospholipase and protease - important virulence-associated enzymes - by C. neoformans and Cryptococcus gattii was also investigated. A total of 36 strains were studied, out of which 20 were from veterinary sources, 8 were from human cases and 8 were from a reference collection. The minimum inhibitory concentrations (MICs) were determined in accordance with the M27-A3 protocol as described by the CLSI and farnesol was tested at a concentration range of 0.29-150μM. Phospholipase and protease activities were evaluated through growth on egg yolk agar and spectrophotometry, respectively, after pre-incubating the strains at different farnesol concentrations (MIC/4, MIC/2 and MIC). It was observed that farnesol presents an inhibitory activity against C. neoformans and C. gattii (MIC range: 0.29-75.0μM). Although farnesol did not significantly alter phospholipase activity, a tendency to decrease this activity was observed. Concerning protease, no statistically significant differences were observed when comparing the production before and after pre-incubation at different farnesol concentrations. Based on these findings, it can be concluded that farnesol has in vitro inhibitory activity against C. neoformans and C. gattii, but has little impact on the production of the analyzed virulence factors.     

Resistance to avermectin/milbemycin anthelmintics in equine cyathostomins - current situation

Avermectins and milbemycins (AM) are potent compounds against all major nematode parasites, but their continuous usage has led to the development of widespread resistance in many of the important species of ruminant and equine parasites. The exception to this has been the cyathostomins, where AM resistance was recently first reported only after decades of drug exposure. Data from a Brazilian study suggests that AM resistance has developed in cyathostomins and reports of shortened egg reappearance periods after ivermectin treatment have been published recently from USA and Germany. Thus, AM resistance in cyathostomins is an emerging worldwide concern, but there is only limited amount data on the extent of this problem. To limit the development and spread of AM-resistant cyathostomins the equine industry must implement new strategies for worm control, and the veterinary parasitology community must develop and validate improved protocols for detecting anthelmintic resistance in the field.     

QTL analysis of main and epistatic effects for flour color traits in durum wheat

The aim of this work was to map quantitative trait loci (QTLs) associated with flour yellow color (Fb*) and yellow pigment content (YPC) in durum wheat (Triticum turgidum L. var. durum). Additionally, QTLs affecting flour redness (Fa*) and brightness (FL*) color parameters were investigated. A population of 93 RILs (UC1113 × Kofa) was evaluated in three locations of Argentina over 2 years. High heritability values (>94%) were obtained for Fb* and YPC, whereas FL* and Fa* showed intermediate to high values. The main QTLs affecting Fb* and YPC overlapped on chromosome arms 4AL (4AL.2), 6AL (6AL.2), 7AS, 7AL, 7BS (7BS.2) and 7BL (7BL.2). The 7BL.1 QTL included the Psy-B1 locus, but one additional linked QTL was detected. A novel minor QTL located on 7AS affected Fb*, with an epistatic effect on YPC. An epistatic interaction occurred between the 7AL and 7BL.2 QTLs. The 4AL.2 QTL showed a strong effect on Fb* and was involved in two digenic epistatic interactions. The 6AL.2 QTL explained most of the variation for Fb* and YPC. The main QTLs affecting FL* and Fa* were located on 2BS and 7BL, respectively. These results confirm the complex inheritance of flour color traits and open the possibility of developing perfect markers to improve pasta quality in Argentinean breeding programs.     

Control of lemon green mold by a sequential oxidative treatment and sodium bicarbonate

A sequential oxidative treatment (SOT), using sodium hypochlorite (NaClO) and hydrogen peroxide (H₂O₂) in the presence of a cupric salt inhibited in vitro growth and germination of Penicillium digitatum conidia, causal agent of citrus green mold. Here, modifications of this SOT were evaluated in vivo to control this disease in inoculated lemons. The treatment that consisted of two sequential 2-min baths: one with 200 mg L⁻¹ NaClO followed by a second with 600 mmol L⁻¹ H₂O₂ in the presence of 6 mmol L⁻¹ CuSO₄, resulted in 50% of disease control. When this treatment was combined with a third 2-min bath containing 30 g L⁻¹ NaHCO₃ at 37 °C (SOT-NaHCO₃) and applied at 24 h post-inoculation, green mold incidence was reduced to ∼5%. In non-inoculated lemons stored at 5 °C for 45 d, this treatment did not modify the appearance or weight compared to untreated lemons. Furthermore, phenolic content and the oxygen consumption rate in flavedo and albedo tissues were not affected by the SOT-NaHCO₃. The malondialdehyde content in flavedo tissues increased immediately after treatment, but decreased to levels similar to control fruit 2 d later. The SOT-NaHCO₃ combines compounds that are safe to the environment and human health, thus it represent a potential alternative to synthetic fungicides for the integrated control of postharvest diseases.     

Nutrition and production of Helianthus annuus in a function of application of leaf silicon

Silicon (Si) is important as it increases plant tolerance to abiotic stresses. However, studies on in foliar fertilization are still scarce. The objective of this research was to evaluate the effect of foliar application of silicon on nutrition and production of Helianthus annuus. The study was carried with a completely randomized design, consisting of five doses of silicon (0; 0.84; 1.68; 2.52 and 3.36?mg L^?1) applied as silicate, with four replicates. Biometric evaluations and relative chlorophyll index (RCI) measurements were performed, being also observed the dry matter production and the silicon use efficiency by plants. The RCI is not affected by the foliar application of Si, while the height and leaf area increase by 8.3 and 25.4%, respectively. Foliar Si application up to the dose of 3.36?g L^?1 promotes linear increases in the dry matter production of shoots (32%), capitulum (19%) and the whole plant of sunflower (27%).     

Interspecific competition changes nutrient : nutrient ratios of weeds and maize

The elemental ratios of plant tissues are associated with the adaptive and competitive success of a plant species in an ecosystem. So far, no study has evaluated if and how crop–weed competition influences the elemental ratios of competing populations, although such information is important to understand weed infestation dynamics and to improve weed management in agroecosystems. The objective of this study was to analyze weed–crop elemental ratios during interspecific competition between weeds and crops in greenhouse experiments. For this, maize (Zea mays L.) and the weeds Amaranthus viridis L, Bidens pilosa L., and Ipomoea grandifolia (Dammer) O'Donell were grown under seven treatments: maize and weed monocultures, and maize in competition with weeds. Competition between plants practically did not influence growth and nutrient contents of maize but reduced weed growth and nutrient uptake. Maize showed few changes in elemental ratios. In contrast, B. pilosa and I. grandifolia were very sensitive to competition and showed significant increases in C : N, C : P, C : K, N : P, and N : K ratios when grown with maize. A. viridis showed low flexibility of nutrient : nutrient ratios under the same competitive pressure as that faced by B. pilosa and I. grandifolia. The interspecific competition led to increases only in the C : P ratio of A. viridis shoots. Therefore, interspecific competition changes the elemental ratios, mainly of the weeds, and the magnitude of this change is dependent on the plant species involved. Interspecific competition changes plant biomass quality (higher C : nutrient ratios), mainly for B. pilosa and I. grandifolia.