Time course of biofilm formation by Staphylococcus aureus and Staphylococcus epidermidis mastitis isolates

Biofilm formation is considered a selective advantage for staphylococci mastitis isolates, facilitating bacterial persistence in the udder. It requires attachment to mammary epithelium, proliferation and accumulation of cells in multilayers and enclosing in a polymeric matrix, being regulated by several loci. As biofilm formation can proceed through different pathways and time ranges, its detection may differ according to the time of observation. This study aimed at evaluating the time course evolution of biofilm production in Staphylococcus aureus (n = 26) and Staphylococcus epidermidis (n = 29) mastitis isolates by Fluorescent In Situ Hybridisation. Biofilm-forming ability increased with incubation time for both species: for S. aureus, 34.6%, 69.2% and 80.8% of the isolates were able to produce biofilm at 24, 48 and 72 h, respectively. For S. epidermidis, 44.8%, 62.1% and 75.9% of the isolates were biofilm-positive at 24, 48 and 72 h, respectively. No significant difference was found between species at each time point (Friedman's test, p > 0.05). For S. aureus, although a significant difference was found between 24 and 48 h (Wilcoxon matched paired test, p < 0.05), no significant difference was found between 24 and 48 h (p > 0.05). For S. epidermidis, significant differences were found between each time point (p < 0.05). Bacterial biofilms may impair eradication of chronic mastitis, rendering antibiotherapy less effective. Detection of biofilm-forming ability in mastitis isolates may provide useful information for the establishment of a more adequate therapeutic regimen, in view of the antimicrobial concentrations required for bacterial control. However, it is essential that biofilm formation time course is taken into consideration.     

Ecological intensification of cropping systems enhances soil functions,mitigates soil erosion,and promotes crop resilience to dry spells in the Brazilian Cerrado

Water scarcity threatens global food security and agricultural systems are challenged to achieve high yields while optimizing water usage. Water deficit can be accentuated by soil physical degradation, which also triggers water losses through runoff and consequently soil erosion. Although soil health in cropping systems within the Brazilian Cerrado biome have been surveyed throughout the years, information about soil erosion impacts and its mitigation are still not well understood; especially concerning the role of cropping system diversification and its effects on crop yield. Thus, the aim of this study was to assess whether ecological intensification of cropping systems –inclusion of a consorted perennial grass and crop rotation– could promote soil coverage and consequently decrease water erosion and soil, water, and nutrient losses. This work studied the effects of crop rotation and consorted Brachiaria, along with different levels of investment in fertilization on soil physical quality and on soil, water, and nutrient losses, and crop yields. Results proved that soybean monoculture (SS) is a system of low sustainability even under no-till in the Brazilian Cerrado conditions. It exhibited high susceptibility to soil, water, and nutrient losses, causing low crop yields. Our results showed that water losses in SS cropping system were approximately 10% of the total annual rainfall, and total K losses would require an additional 35% of K application. Conversely, ecological intensification of cropping systems resulted in enhanced soil environmental and agronomic functions, increased grain yield, and promoted soil and water conservation: high soil cover rate, and low soil, water and nutrient losses. Ecological intensification proved to be an adequate practice to boost crop resilience to water deficit in the Brazilian Cerrado.     

Prevalence and risk factors associated with swine gastrointestinal nematodes and coccidia in the semi-arid region of northeastern Brazil

Tropical Animal Health and Production - In northeastern Brazil, with has a predominantly dry climate, farmers seek alternative sources of income and livelihood by the rearing pigs. The...     

Genetic diversity of Brazilian farmers-made strawberry genotypes and their relationship with commercial cultivars

Genetic Resources and Crop Evolution - The cultivated strawberry [Fragaria × ananassa (Duchesne ex Weston) Duchesne ex Rozier] is one of the most valuable small fruits worldwide....     

Repeatability of full-sib sugarcane families across harvests and the efficiency of early selection

This study was designed to estimate the repeatability coefficient of traits of the plant-cane and first rattoon in a large number of full-sib sugarcane families and to select the superior families based on their predicted genotypic values. The population used in this study consisted of 190 families, and crossing was performed at the Federal University of Alagoas, in Murici, Alagoas, Brazil, in 2007. Five experiments, each with 22 families, took place at the Centro de Pesquisa e Melhoramento da Cana-de-Açúcar (CECA), in Oratórios, Minas Gerais, while four experiments, each with 20 families, took place at the Volta Grande mill (VGM), in Conceição das Alagoas, Minas Gerais. Each experiment took the form of a randomized complete block design with six replications. The following traits were determined from the plant-cane and first rattoon: percentage of soluble solids w/w in the juice (Brix), tons of stalks per hectare (TSH) and tons of brix per hectare (TBH). Statistical analyses were performed using the mixed model methodology. Variance components were estimated by restricted maximum likelihood (REML) and the genotypic values of families were predicted by best linear unbiased prediction (BLUP). The moderately high estimates of repeatability for TSH and TBH and the high rates of coincidences of the families selected in both plant-cane and first rattoon indicate that selection of families using repeated measures across the first two harvests combined with individual clone selection at the rattoon stage may be efficient in sugarcane breeding programs, increasing the efficiency of obtaining new cultivars.     

Fatal coccidiosis by Isospora icterus (Upton & Whitaker, 2000) in captive Campo Troupial (Icterus jamacaii) in Brazil

An outbreak of coccidiosis by Isospora icterus (I. icterus, Upton & Whitaker, 2000) in captive Campo Troupial (Icterus jamacaii) (Gmelin, 1788) at the Wild Animals Triage Center (IBAMA, Belo Horizonte, Brazil) is described. Clinical history and the necropsy findings documented diarrhea with diffuse necrotic enteritis. Sporulated oocysts (n = 100) had a bilayered wall, were subspherical, and measured 30.1 (27.5-32.5) microm in length and 28.5 (26.2-30.0) microm in width. A polar body but no micropyle was present and the length/width ratio was 1.1 (1.00-1.2). Each oocyst contained two ellipsoidal sporocysts measuring 17.6 (15.0-20.0) microm in length and 12.9 (12.5-15.0) microm in width, with a length/width ratio of 1.4 (1.2-1.5), and with Stieda and sub-Stieda bodies. Each sporocyst contained four sporozoites with granular sporocyst residuum. Oocysts were compatible with those from I. icterus, previously described in Campo Troupial.     

Silicon induces resistance to Diatraea saccharalis in sugarcane and it is compatible with the biological control agent Cotesia flavipes

Journal of Pest Science - The sugarcane borer Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae) is a major pest of sugarcane (Saccharum sp.) (Glumiflorae: Poaceae) in Brazil and has been...     

Genetic parameters and correlation in early measurement cycles in rubber trees

Knowledge of the traits present in plant populations of a species is essential to carry out selection and breeding. The objective of the present study was to estimate the genetic parameters and correlate genetically and phenotypically the variables rubber yield, annual trunk girth increase, number of latex vessel rings and bark thickness in early measurement cycles. A total of 22 rubber tree progenies (Hevea brasiliensis) were assessed in three locations during three early measurement cycles. The bark thickness variable correlated significantly for the three increase measurements made in the locations of Jaú, Pindorama and Votuporanga. The progeny mean based joint hereditability showed mean values greater than individual plants and within progeny plants of 0.848, 0.286 and 0.242, respectively. The variables annual trunk girth increase and bark thickness are genetically correlated variables. Rubber yield is correlated genetically with bark thickness that permits simultaneous selection for the two characteristics. The early measurement cycles were efficacious for finding genetic variability among the genotypes.     

Infection process and defense response of two distinct symptoms of Cercospora leaf spot in coffee leaves

Phytoparasitica - Cercospora leaf spot, an important disease in coffee caused by the fungus Cercospora coffeicola, can appear as two distinct symptoms on leaves, which are ‘brown eye...