Genetic uniqueness of Cryptosporidium parvum from dairy calves in Colombia

Fecal specimens from 432 pre-weaned calves younger than 35 days were collected over a 2-year period (2010–2012) from 74 dairy cattle farms in the central area of Colombia. These samples were microscopically examined for the presence of Cryptosporidium oocysts, and positive specimens were selected for molecular examination. Microscopy revealed that 115 calves (26.6%) from 44 farms (59.5%) tested positive. Oocyst shedding was recorded in calves aged 3-day-old onwards, although the infection rate peaked at 8–14 days (40.7%). Infection rates were higher in diarrheic (52.2%) than in non-diarrheic calves (19.9%) (p < 0.0001, ¿2), and infected calves had up to seven times more probability of having diarrhea than non-infected calves. Cryptosporidium species and subtypes were successfully identified in 73 samples from 32 farms. Restriction and sequence analyses of the SSU rRNA gene revealed C. parvum in all but two isolates identified as Cryptosporidium bovis. Sequence analyses of the 60-KDa glycoprotein (gp60) gene revealed eight subtypes within the IIa family. An unusual subtype (IIaA18G5R1) was the most prevalent and widely distributed (more than 66% specimens and 68% farms) while the subtype most frequently reported in cattle worldwide (IIaA15G2R1) was found in less than 13% of specimens and 16% farms. The remaining subtypes (IIaA16G2R1, IIaA17G4R1, IIaA20G5R1, IIaA19G6R1, IIaA20G6R1, and IIaA20G7R1) were restricted to 1–3 farms. This is the first large-sample size study of Cryptosporidium species and subtypes in Colombia and demonstrates the genetic uniqueness of this protozoan in cattle farms in this geographical area

Host association of cryptosporidium parvum populations infecting domestic ruminants in Spain

A stock of 148 Cryptosporidium parvum DNA extracts from lambs and goat kids selected from a previous study examining the occurrence of Cryptosporidium species and GP60 subtypes in diarrheic lambs and goat kids in northeastern Spain was further characterized by a multilocus fragment typing approach with six mini- and microsatellite loci. Various degrees of polymorphism were seen at all but the MS5 locus, although all markers exhibited two major alleles accounting for more than 75% of isolates. A total of 56 multilocus subtypes (MLTs) from lambs (48 MLTs) and goat kids (11 MLTs) were identified. Individual isolates with mixed MLTs were detected on more than 25% of the farms, but most MLTs (33) were distinctive for individual farms, revealing the endemicity of cryptosporidial infections on sheep and goat farms. Comparison with a previous study in calves in northern Spain using the same six-locus subtyping scheme showed the presence of host-associated alleles, differences in the identity of major alleles, and very little overlap in MLTs between C. parvum isolates from lambs and those from calves (1 MLT) or isolates from lambs and those from goat kids (3 MLTs). The Hunter-Gaston index of the multilocus technique was 0.976 (95% confidence interval [CI], 0.970 to 0.982), which supports its high discriminatory power for strain typing and epidemiological tracking. Population analyses revealed the presence of two host-associated subpopulations showing epidemic clonality among the C. parvum isolates infecting calves and lambs/goat kids, respectively, although evidence of genetic flow between the two subpopulations was also detected

Enhancing predicted fluoride varnish efficacy and post-treatment compliance by means of calcium-containing gummy bears

Objectives This study determined whether consumption of calcium-containing gummies prior to fluoride varnish application enhances plaque fluoride retention and compliance with post-varnish application instructions. Methods The present study followed a multi-center, parallel, randomized, and laboratory analyst-blind design. Following IRB approval, parent consent and child assent, 44 subjects (7–12 years), were randomized to either gummy or no-gummy study groups. A baseline plaque sample was obtained after a wash-out period. Fluoride varnish (5% NaF) was applied; subjects in the gummy group received two calcium-containing gummies prior to varnish application. Subjects were given two questionnaires to complete (subject and parent) to investigate adherence to post-treatment instructions. Three days later, a second plaque sample was obtained. Plaque was analyzed for plaque fluid and solid fluoride concentrations. Fluoride data were analyzed using Wilcoxon Rank Sum tests, questionnaire data using Pearson chi-square tests. Results Plaque fluid fluoride did not change pre- to post-treatment in the gummy group (mean ± sd: 8.8 ± 5.7 μmol/l vs. 10.0 ± 6.3 μmol/l; p = 0.265) or in the no-gummy group (8.1 ± 4.4 μmol/l vs. 16.1 ± 20.0 μmol/l; p = 0.058). Groups were not different for plaque fluid fluoride pre-treatment (p = 1.000), post-treatment (p = 0.904), or change (p = 0.904). Plaque solid fluoride did not change pre- to post-treatment in the gummy group (0.89 ± 1.10 μmol/g vs. 1.37 ± 1.77 μmol/g; p = 0.073) or in the no-gummy group (0.68 ± 0.77 μmol/g vs. 2.01 ± 5.00 μmol/g; p = 0.190). Groups were not different for plaque solid fluoride pre-treatment (p = 1.000), post-treatment (p = 0.466), or change (p = 0.874). No significant differences were found between groups for questionnaire responses. Conclusion This study failed to demonstrate an effect of calcium-containing gummies in enhancing plaque fluoride retention

Divergencia del régimen tributario aplicable a los clubes profesionales en Colombia

Artículo de investigaciónEn el presente artículo el lector encontrará un breve estudio acerca del régimen jurídico tributario aplicable a los clubes deportivos profesionales en Colombia destacando las divergencias de disposiciones normativas a las que están sometidos los mismos, toda vez que, le es permitido estructurarse bajo la forma de una asociación civil o de una sociedad anónima, lo cual opera en perjuicio de la competencia, pues la diversa carga tributaria a la que se ven sometidos genera inequidad en las cargas operativas de los clubes competidores. Todo lo anterior se analizará críticamente a partir del mandato constitucional de fomento del deporte que se ha establecido a cargo del Estado.PregradoAbogad

Review of \u3ci\u3eUrochloa\u3c/i\u3e Breeder’s Toolbox with the Theory of Change and Stage Gate System Approach

Livestock production in the global south is at crossroads as there is a demand to increase Animal Source Foods to address hunger and pressure to lighten the environmental footprint often associated with livestock production. To satisfy both needs, the use of technologies that improve animal performance, while reducing land use and net Greenhouse Gas emissions produced by animals is essential. One of such technologies are Urochloa forage grasses. Urochloa forage grasses are well known for their rusticity and their ability to grow in soils of low fertility and high aluminum content. These characteristics allow Urochloa to grow in areas temporally or spatially less suitable for crop production, but also have made ruminants production profitable in areas that would not be otherwise. However, productivity and sustainability of ruminant production in these areas is likely to fall within the next decade due to climate change unless action is taken. Despite these known benefits of Urochloa forage species, breeding programs have long delayed initiation due to apomixes and differences in ploidy. In the mid-1980s, the development of suitable sexual germplasm allowed crossings, and therefore favoured the emergence of breeding programs. In recent decades, several advances in biology, molecular biology, phenotyping, population genetics, genomics and transcriptomics have generated a plethora of information that ought to be integrated for its use in a single breeding toolbox. We use the Theory of Change and Stage-Gate systems approach to review these advances in research and the utility of the current and future available tools. Further, we address the remaining lack of information, thus bridging the knowledge gap and enabling us to maximize the genetic gain in the different Urochloa breeding programs. In this way, we identify breeding bottlenecks and help to pinpoint priorities for Urochloa research and development

Diverged subpopulations in tropical Urochloa (Brachiaria) forage species indicate a role for facultative apomixis and varying ploidy in their population structure and evolution

Abstract Background Urochloa (syn. Brachiaria) is a genus of tropical grasses sown as forage feedstock, particularly in marginal soils. Here we aimed to clarify the genetic diversity and population structure in Urochloa species to understand better how population evolution relates to ploidy level and occurrence of apomictic reproduction. Methods We explored the genetic diversity of 111 accessions from the five Urochloa species used to develop commercial cultivars. These accessions were conserved from wild materials collected at their centre of origin in Africa, and they tentatively represent the complete Urochloa gene pool used in breeding programmes. We used RNA-sequencing to generate 1.1 million single nucleotide polymorphism loci. We employed genetic admixture, principal component and phylogenetic analyses to define subpopulations. Results We observed three highly differentiated subpopulations in U. brizantha, which were unrelated to ploidy: one intermixed with U. decumbens, and two diverged from the former and the other species in the complex. We also observed two subpopulations in U. humidicola, unrelated to ploidy; one subpopulation had fewer accessions but included the only characterized sexual accession in the species. Our results also supported a division of U. decumbens between diploids and polyploids, and no subpopulations within U. ruziziensis and U. maxima. Conclusions Polyploid U. decumbens are more closely related to polyploid U. brizantha than to diploid U. decumbens, which supports the divergence of both polyploid groups from a common tetraploid ancestor and provides evidence for the hybridization barrier of ploidy. The three differentiated subpopulations of apomictic polyploid U. brizantha accessions constitute diverged ecotypes, which can probably be utilized in hybrid breeding. Subpopulations were not observed in non-apomictic U. ruziziensis. Sexual Urochloa polyploids were not found (U. brizantha, U. decumbens) or were limited to small subpopulations (U. humidicola). The subpopulation structure observed in the Urochloa sexual–apomictic multiploidy complexes supports geographical parthenogenesis, where the polyploid genotypes exploit the evolutionary advantage of apomixis, i.e. uniparental reproduction and clonality, to occupy extensive geographical areas

Complex polyploid and hybrid species in an apomictic and sexual tropical forage grass group: genomic composition and evolution in Urochloa (Brachiaria) species

Background and Aims Diploid and polyploid Urochloa (including Brachiaria, Panicum and Megathyrsus species) C-4 tropical forage grasses originating from Africa are important for food security and the environment, often being planted in marginal lands worldwide. We aimed to characterize the nature of their genomes, the repetitive DNA and the genome composition of polyploids, leading to a model of the evolutionary pathways within the group including many apomictic species. Methods Some 362 forage grass accessions from international germplasm collections were studied, and ploidy was determined using an optimized flow cytometry method. Whole-genome survey sequencing and molecular cytogenetic analysis were used to identify chromosomes and genomes in Urochloa accessions belonging to the 'brizantha' and 'humidicola' agamic complexes and U. maxima. Key Results Genome structures are complex and variable, with multiple ploidies and genome compositions within the species, and no clear geographical patterns. Sequence analysis of nine diploid and polyploid accessions enabled identification of abundant genome-specific repetitive DNA motifs. In situ hybridization with a combination of repetitive DNA and genomic DNA probes identified evolutionary divergence and allowed us to discriminate the different genomes present in polyploids. Conclusions We suggest a new coherent nomenclature for the genomes present. We develop a model of evolution at the whole-genome level in diploid and polyploid accessions showing processes of grass evolution. We support the retention of narrow species concepts for Urochloa brizantha, U. decumbens and U. ruziziensis, and do not consider diploids and polyploids of single species as cytotypes. The results and model will be valuable in making rational choices of parents for new hybrids, assist in use of the germplasm for breeding and selection of Urochloa with improved sustainability and agronomic potential, and assist in measuring and conserving biodiversity in grasslands

THE TRAM-FPV RACING Open Database. Sequences complete indoor flight tests for the study of racing drones

This paper presents the TRAM-FPV Racing open database, generated from a set of indoor flights performed with five racing drones at Cranfield University (UK), specifically at the Flight Arena, one of the largest indoor flight fields in the world for research purposes. The database incorporates the position and orientation information in the space of five racing drone models using an optical measurement system (OMS). It includes readings from accelerometers, gyroscopes, and heading angles recorded by inertial unit (IMU) sensors. These databases are frequently used to develop and adjust the sensor fusion algorithms incorporated in the drones to estimate their current state vector. However, their field of application is vast, being able to be used, for example, for the development of the nonlinear mathematical models of drones or the generation of trajectories

Genotype-by-Environment Interaction in Interspecific \u3cem\u3eUrochloa\u3c/em\u3e Hybrids Using Factor Analytic Models

Environmental factors can influence plant phenotypes shaping the expression of pastures. The ability to test genotypes in multiple environments is critical in a breeding program because important traits are heavily influenced by the environment. Nutritional quality is critical in forage breeding because it affects the rate of live weight gain in livestock as well as the quality of end products such as milk and meat. However, there is not much information on the environmental effect on agronomic and nutritional quality traits in tropical forages. For this reason, the objective of the present study was to investigate the genotype-by-environment interaction in a breeding population of interspecific Urochloa hybrids evaluated for agronomic and nutritional quality traits across four locations in Colombia, using factor analytic mixed models. Phenotypic correlations among traits ranged from 0.26 (plant area vs dry weight) to 0.93 (fresh weight vs dry weight), indicating a strong interaction in some traits. Genetic correlations among environments showed different ranges depending on the variable evaluated. For example, plant height genetic correlations among environments ranged from 0.16 to 0.9, indicating high genotype-byenvironment interaction. The factor analytic analysis revealed that two factors explained more than 60% of the genetic variance in all traits evaluated and that 80% of the environments were clustered in the first factor. Factor analytic biplot indicates that Llanos location differed strongly from other locations evaluated. Based on the results obtained, the factor analytic analysis is a useful tool to stratify environments and identify Urochloa cultivars adapted to different ecological niches

The impact of secondary forest regeneration on ground-dwelling ant communities in the Tropical Andes

Natural regeneration of abandoned farmland provides an important opportunity to contribute to global reforestation targets, including the Bonn Challenge. Of particular importance are the montane tropics, where a long history of farming, frequently on marginal soils, has rendered many ecosystems highly degraded and hotspots of extinction risk. Ants play crucial roles in ecosystem functioning, and a key question is how time since abandonment and elevation (and inherent temperature gradients therein) affect patterns of ant recovery within secondary forest systems. Focusing on the Colombian Andes across a 1300 m altitudinal gradient and secondary forest (2–30 years) recovering on abandoned cattle pastures, we find that over time ant community composition and species richness recovered towards that of primary forest. However, these relationships are strongly dependent on elevation with the more open and warmer pasturelands supporting more ants than either primary or secondary forest at a particular elevation. The loss of species richness and change in species composition with elevation is less severe in pasture than forests, suggesting that conditions within pasture and its remaining scattered trees, hedgerows and forest fragments, are more favourable for some species, which are likely in or near thermal debt. Promoting and protecting natural regenerating forests over the long term in the montane tropics will likely offer significant potential for returning ant communities towards primary forest levels