Intraspecific Evolution of Rhizoctonia solani AG-1 IA Associated with Soybean and Rice in Brazil based on Polymorphisms at the ITS-5.8S rDNA Operon

Rhizoctonia solani AG-1 IA causes leaf blight on soybean and rice. Despite the fact that R. solani AG-1 IA is a major pathogen affecting soybean and rice in Brazil and elsewhere in the world, little information is available on its genetic diversity and evolution. This study was an attempt to reveal the origin, and the patterns of movement and amplification of epidemiologically significant genotypes of R.solani AG-1 IA from soybean and rice in Brazil. For inferring intraspecific evolution of R. solani AG-1 IA sampled from soybean and rice, networks of ITS-5.8S rDNA sequencing haplotypes were built using the statistical parsimony algorithm from Clement et al. (2000) Molecular Ecology 9: 1657-1660. Higher haplotype diversity (Nei M 1987, Molecular Evolutionary Genetics Columbia University Press, New york: 512p.) was observed for the Brazilian soybean sample of R. solani AG-1 IA (0.827) in comparison with the rest of the world sample (0.431). Within the south-central American clade (3-2), four haplotypes of R.solani AG-1 IA from Mato Grosso, one from Tocantins, one from Maranhão, and one from Cuba occupied the tips of the network, indicating recent origin. The putative ancestral haplotypes had probably originated either from Mato Grosso or Maranhão States. While 16 distinct haplotypes were found in a sample of 32 soybean isolates of the pathogen, the entire rice sample (n=20) was represented by a single haplotype (haplotype 5), with a worldwide distribution. The results from nested-cladistic analysis indicated restricted gene flow with isolation by distance (or restricted dispersal by distance in nonsexual species) for the south-central American clade (3-2), mainly composed by soybean haplotype

Ferrugem‑asiática da soja no Brasil: passado, presente e futuro

Asian soybean rust, caused by the fungus Phakopsora pachyrhizi, is the most severe disease of the crop and can cause yield losses of up to 90%. The disease was first reported in Brazil in 2001. Epidemics of the disease are common in the country, where the fungus can survive year‑round. Regulatory measures to reduce the inoculum between seasons and avoid late-season soybean have been adopted to manage the disease. Disease control has relied mainly on chemical control, but a lower sensibility of the fungus to fungicides has been reported in Brazil. Major‑resistance genes have been mapped and incorporated into the cultivars. With the reduced efficacy of the fungicides, the adoption of integrated measures to control the disease will be important for the sustainability of the crop. This review presents the main changes in the soybean crop system caused by the introduction of the fungus in Brazil, the current management strategies adopted to avoid losses, and the new trends that, together with biotechnological strategies, can improve management in the future.A ferrugem‑asiática da soja, causada pelo fungo Phakopsora pachyrhizi, é a doença mais severa da cultura e pode causar perdas de produtividade de até 90%. A doença foi relatada pela primeira vez no Brasil em 2001. Epidemias da doença são comuns no País, onde o fungo pode sobreviver durante todo o ano. Medidas regulatórias para reduzir o inóculo entre safras e evitar a semeadura tardia de soja têm sido adotadas para manejar a doença. O controle da doença tem se baseado principalmente no controle químico, mas uma menor sensibilidade do fungo aos fungicidas tem sido relatada no Brasil. Genes de resistência têm sido mapeados e incorporados às cultivares. Por causa da redução da eficiência dos fungicidas, a adoção de medidas integradas para o controle da doença será importante para a sustentabilidade da cultura. Este artigo de revisão apresenta as principais mudanças no sistema de produção da soja causadas pela introdução do fungo no Brasil, as medidas de controle atualmente usadas para evitar perdas, e as novas tendências que, juntas com estratégias biotecnológicas, podem melhorar o manejo da doença no futuro

Thermoregulation during exercise in the heat of American football players

American football players might face challenges during a prolonged exercise in the heat which can lead to impairments in performance and induce heat-related illness. The purpose of this study was to verify the body temperature and sweating responses in American football players while exercising at a moderate-high intensity effort as prescribed by metabolic heat production. Seven heat-acclimatized players participated in the study. Players exercised 4×20-min bouts at moderate-high intensity as 8.0W.kg-1 of metabolic heat production, with 10min rest between them, totalizing 110min of heat exposure (39oC and 50% relative humidity). Rectal (Tre) and skin (Tsk) temperatures, heart rate (HR), metabolic heat production were measured continuously. Dehydration was calculated from Δbody mass pre-and post-exercise. Initial Tre and HR were 37.0 ± 0.3 °C and 80 ± 9 beats.min-1, respectively. Players began the trial euhydrated according to the initial urine specific gravity (1.014 ± 0.008) and colour (2.4 ± 1.4). During experimental trial, core temperature increased overtime (p < .001) resulting in a ΔTre of 2.2 ± 0.6 °C. Average HR during exercise was 166 ± 11 beats.min-1 and weighted Tsk was 36.7 ± 0.5 °C. Sweat volume was 2.6 ± 0.3 L, resulting a % hypohydration of -3.1 ± 0.4 % reflecting a moderate level of hypohydration. Final urine specific gravity and colour were 1.024 ± 0.009 and 5.0 ± 1.0, respectively. Experimental trials were interrupted at the end of the third and the fourth exercise bouts in two players due to the respective adverse conditions: leg muscle cramps, and excessive Tre increase (reached 39.9 °C). Thermoregulation and hydration must be a major concern, mainly related to greater exercise intensities and long-time practice, inducing high hypohydration levels and risk of hyperthermia

Fungitoxicidade de grupos químicos sobre Myrothecium roridum in vitro e sobre a mancha-de-mirotécio em algodoeiro

The objective of this work was to evaluate the toxicity of benzimidazoles, triazoles, strobilurins, isoftalonitrils and ditiocarbamats on Myrothecium roridum conidial germination and micelial growth in vitro, and the myrothecium leaf spot severity on cotton plants. On in vitro tests, fungicides were solubilized in PDA media at the following concentrations: 0.1, 1, 10 and 100 mg L-1. The toxicity of the products were evaluated by the ED50 rate (required for inhibiting 50% of the conidial germination or mycelial growth). In greenhouse tests, the severity of myrothecium leaf spot was quantified by measuring the leaf area affected by the pathogen in cotton plants sprayed before (preventive) and after (curative) the pathogen inoculation. The fungicides thiophanate methyl, carbendazim, metconazole, thiophanate methyl + chlorothalonil, pyraclostrobin + epoxyconazole, pyraclostrobin + metiran, trifloxystrobin + propiconazole, and tebuconazole were highly efficient (ED50<1 mg L-1) or efficient (ED50 between 1 and 10 mg L-1) inhibiting conidial germination and mycelial growth of M. roridum isolates. In greenhouse tests, fungicides pyraclostrobin + epoxyconazole, tebuconazole, metconazole, and azoxystrobin + cyproconazole are the most efficient against myrothecium leaf spot disease. Preventive treatment is more efficient than curative.O objetivo deste trabalho foi avaliar a fungitoxicidade de produtos pertencentes aos grupos dos benzimidazóis, triazóis, estrobilurinas, isoftalonitrilas e ditiocarbamatos sobre a germinação conidial e o crescimento micelial in vitro de isolados de Myrothecium roridum e, in vivo, sobre a severidade da mancha-de-mirotécio em plantas de algodoeiro. Nos testes in vitro os fungicidas foram solubilizados em meio BDA, utilizando-se as concentrações de 0,1, 1, 10 e 100 mg L-1 de ingrediente ativo. A fungitoxidade dos produtos foi avaliada por meio da ED50 (dose necessária para inibir 50% da germinação conidial ou crescimento micelial). Em casa de vegetação, estimou-se a severidade da mancha-de-mirotécio pela porcentagem de área foliar lesionada nas plantas de algodoeiro tratadas antes (preventivo) e depois (curativo) da inoculação do patógeno. Os fungicidas tiofanato metílico, carbendazim, metconazol, tiofanato metílico + clorotalonil, piraclostrobina + epoxiconazol, piraclostrobina + metiram, triflostrobina + propiconazol e tebuconazol inibiram com alta eficácia (ED50<1 mg L-1), ou com eficácia (ED50 entre 1 e 10 mg L-1), a germinação conidial e o crescimento micelial in vitro de M. roridum. Os fungicidas piraclostrobina + epoxiconazol, tebuconazol, metconazol e azoxistrobina + ciproconazol são os mais eficazes em testes in vivo. O tratamento preventivo é mais eficaz que o curativo

Estudo das condições de saúde das crianças do Município de São Paulo (Brasil), 1984/1985: IX - Cobertura e qualidade da assistência materno-infantil

A survey of 1,016 randomly selected children under five years of age was carried out in S. Paulo city, Brazil, with a view to studying the epidemiology of health conditions. The quality and the coverage of maternal and child care were observed. Both characteristics were estimated by means of domiciliary interviews. The prenatal care coverage was 92.9%. In 70% of the cases prenatal care started in the first quarter of pregnancy and the number of visits was 6 or more. Ninety-nine percent of the children were born in hospitals and in 47.1% of the cases caesarean section was mentioned. Ninety-eight percent of the children went, at least once, to well-baby clinics, about two thirds of them during the first two months of life. With regard to the activities provided by those clinics, a great concentration of visits in the first year of life (averaging 7.7 visits per child) was observed as well as a high percentage of immunized children (Sabin 86.7%, DPT 85.1%, BCG 89.0%, Measles 85.9%), a striking decrease of visits after 12 months of age and a very small proportion of children attended by an odontology specialist (19.5%). Considering the global coverage of maternal and infant care, minimal differences were observed between socioeconomic strata. Nevertheless the differences were impressive when qualitative aspects of the care were taken into account. Compared with other surveys made in Brazil, the present one shows that the situation of S. Paulo city is better than that of other urban areas of the country. It was also observed that there has been an increase in maternal and child care coverage over the last decade. The main problems still found in the city seem to be related to the qualitative aspects of the assistance. Early attraction of women for prenatal care and an increase in the coverage of well-baby clinics after the first year of life are definitely necessary, particularly for the poorest segments of the population. One important aspect which is a reason for concern is the enormous incidence of caesarean sections one of the highest ever registered in a population.Como parte de investigação epidemiológica sobre condições de saúde na infância, foram estudadas a cobertura e a qualidade da assistência materno-infantil prestada à população do Município de São Paulo. Todas as estimativas do estudo baseiam-se em dados obtidos através de inquérito recordatório aplicado a uma amostra representativa de crianças menores de cinco anos residentes no Município (n = 1.016). A cobertura da assistência pré-natal foi estimada em 92,9%, sendo que em cerca de 70% dos casos a assistência foi iniciada no primeiro trimestre de gestação e o número de consultas realizadas foi de seis ou mais. A cobertura da assistência hospitalar ao parto foi estimada em 99,0%, observando-se que 47,1% das crianças nasceram através de cesareanas. A cobertura da assistência de puericultura foi estimada em 98,0%, sendo que em dois terços das vezes a assistência foi iniciada nos primeiros dois meses de vida. Ainda com relação à puericultura, pôde-se observar: grande concentração de consultas no primeiro ano de vida (em média 7,7 consultas), percentagem relativamente alta de crianças vacinadas (Sabin = 86,7%, Tríplice = 85,1%, BCG = 89,0%, Anti-sarampo = 85,9%), decréscimo expressivo de consultas após a idade de doze meses e pequena proporção de crianças com assistência odontológica (19,5%). A estratificação social da população revelou diferenciais sócio-econômicos mínimos quanto à cobertura geral da assistência materno-infantil, observando-se, entretanto, diferenças expressivas quanto a aspectos qualitativos da assistência. Comparando-se o presente inquérito com outros realizados no país, observa-se que a situação de São Paulo apresenta-se mais favorável do que a observada no conjunto das áreas urbanas brasileiras. Verifica-se também que tem sido positiva a evolução recente da assistência materno-infantil no Município. As principais deficiências ainda encontradas dizem respeito a características relacionadas à qualidade da assistência, sendo imprescindível, sobretudo nos estratos populacionais de pior nível sócio-econômico, elevar a cobertura da assistência pré-natal precoce e a cobertura de puericultura após o primeiro ano de vida. Um item especialmente preocupante relacionado à assistência ao parto foi a alta incidência de cesareanas, uma das maiores já registrada em uma população