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Body perception is an individual’s ability to recognize their body in attitudinal and/or dimensional aspects. We investigated women’s body perceptions before and after bariatric surgery. Participants were 31 women ( M age = 36.23, SD = 7.95 years old) with an average pre-operative body mass index of 44.58 ( SD = 4.65) kg/m2. We collected anthropometric and body perception measures (attitudinal body image [ABI] and dimensional body image [DBI]) before bariatric surgery and 30, 60, 90, and 120 days after it. There was an average decrease of 21.09% in participants’ body weight over the 120 days. Regarding ABI, 51.61% of participants had high body dissatisfaction before surgery, and this proportion of dissatisfied participants decreased to 3.23% 120 days after surgery. We observed no statistically significant differences in DBI perceptions. Fast weight loss caused by bariatric surgery appeared to generate a perception of ghost fat. Somatosensory interventions and/or a longer follow-up are needed to alter this persistent distortion of body dimensions.

Andrade RosárioNacha Samadi,de SouzaPerciliany Martins, AssunçãoPoliana Elisa, Pereira de OliveiraFernando Luiz, BearzotiEduardo, de Castro PintoKelerson Mauro,SouzaGabriela Guerra Leal.Resting heart rate variability in professors: Impact of psychological stress, obesity and blood pressure.Journal of Education, Health and Sport. 2021;11(5):11-25. eISSN 2391-8306. DOI http://dx.doi.org/10.12775/JEHS.2021.11.05.001 https://apcz.umk.pl/czasopisma/index.php/JEHS/article/view/JEHS.2021.11.05.001 https://zenodo.org/record/4733067 The journal has had 5 points in Ministry of Science and Higher Education parametric evaluation. § 8. 2) and § 12. 1. 2) 22.02.2019. © The Authors 2021; This article is published with open access at Licensee Open Journal Systems of Nicolaus Copernicus University in Torun, Poland Open Access. This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author (s) and source are credited. This is an open access article licensed under the terms of the Creative Commons Attribution Non commercial license Share alike. (http://creativecommons.org/licenses/by-nc-sa/4.0/) which permits unrestricted, non commercial use, distribution and reproduction in any medium, provided the work is properly cited. The authors declare that there is no conflict of interests regarding the publication of this paper. Received: 21.04.2021. Revised: 26.04.2021. Accepted: 02.05.2021. Resting heart rate variability in professors: Impact of psychological stress, obesity and blood pressure MSc. Nacha Samadi Andrade Rosário1(nacha.rosario@aluno.ufop.edu.br), MSc. Perciliany Martins de Souza1(perciliany.souza@aluno.ufop.edu.br), Poliana Elisa Assunção1(popoelisa@gmail.com), PhD. Fernando Luiz Pereira de Oliveira2(fernandoluiz@ufop.edu.br), PhD. Eduardo Bearzoti2(eduardo.bearzoti@ufop.edu.br), PhD. Kelerson Mauro de Castro Pinto3(kelerson@ufop.edu.br), and PhD. Gabriela Guerra Leal Souza1(gabriela.souza@ufop.edu.br). Laboratory of Psychophysiology, Department of Biological Sciences, Federal University of Ouro Preto, Ouro Preto, Brazil Department of Statistics, Federal University of Ouro Preto, Ouro Preto,Brazil SchoolofPhysical Education, Federal University of Ouro Preto, Ouro Preto,Brazil Corresponding author: Gabriela Guerra Leal Souza; Federal University of Ouro Preto, Department of Biological Sciences, Campus Morro do Cruzeiro, Laboratory of Psychophysiology – Ouro Preto, Minas Gerais – Brasil. CEP 35400-000; e-mail: gabriela.souza@ufop.edu.br; +55 (31) 3559-1991 / (31) 9 8864-2549Email Abstract Objective:University professors are prone to show physical and psychological diseases related to excessive workload. Such overwork can affect the functioning of the autonomic nervous system, leading to a decrease in heart rate variability (HRV). HRV reflects the continuous fluctuation of the R-R intervals due to sympathetic and parasympathetic actions in the heart and is associated with good physical and psychological health.We aimed to evaluate whether psychological stress and anthropometric and clinical variables influence HRV at rest in professors. Methods:University professors of both sexes (N=65; 41 men) participated. We collected Anthropometry and Clinical variables, Psychological stress, and HRV parasympathetic parameters (square root mean squares of the differences between RR intervals: RMSSD, number of successive differences between RR intervals, which are > 50 ms: NN50 and high frequency – HF). Results:Four principal components (PCs) represented 68.29% of the data total variation. Principal component 1 (PC1) was called the good cardiac regulation component. PC2 was called the component of reduced stress symptoms. PC3 was named favorable working conditions component. PC4 was denominated component of labor and physiological deregulation. Each HRV parameter was associated with each PC through the use of regression models. The RMSSD was positively associated with PC2. The NN50 was positively associated with PC2 and PC3. HF was positively associated with PC3 and PC4. Conclusions:HRV parasympathetic parameters, which represent good physical and mental health, are positively associated with the components of reduced stress symptoms, favorable working conditions, and labor and physiological deregulation. Keywords: heart rate variability; stress; blood pressure; obesity; anthropometry;professors. Abstrata Objetivo:Professores universitários são propensos a apresentar doenças físicas e psicológicas relacionadas à carga horária excessiva.Esse excesso de trabalho pode afetar o funcionamento do sistema nervoso autônomo, levando a uma diminuição da variabilidade da frequência cardíaca (VFC).A VFC reflete a flutuação contínua dos intervalos RR devido às ações simpáticas e parassimpáticas no coração e está associada a uma boa saúde física e psicológica.Objetivamos avaliar se o estresse psicológico e as variáveis antropométricas e clínicas influenciam a VFC em repouso em professores.Métodos:Participaram professores universitários de ambos os sexos (N = 65; 41 homens).Coletamos variáveis antropométricas e clínicas, estresse psicológico e parâmetros parassimpáticos da VFC (raiz quadrada da média dos quadrados das diferenças entre os intervalos RR: RMSSD, número de diferenças sucessivas entre os intervalos RR, que são> 50 ms: NN50 e alta frequência - HF).Resultados:Quatro componentes principais (PCs) representaram 68,29% da variação total dos dados.O componente principal 1 (PC1) foi denominado componente de boa regulação cardíaca.PC2 foi chamado de componente de redução dos sintomas de estresse.O PC3 foi denominado componente de condições favoráveis de trabalho.PC4 foi denominado componente do parto e desregulamentação fisiológica.Cada parâmetro de VFC foi associado a cada PC por meio do uso de modelos de regressão.O RMSSD foi positivamente associado ao PC2.O NN50 foi associado positivamente com PC2 e PC3.HF associou-se positivamente com PC3 e PC4.Conclusões: Osparâmetros parassimpáticos da VFC, que representam boa saúde física e mental, estão positivamente associados aos componentes de redução dos sintomas de estresse, condições favoráveis de trabalho e desregulamentação fisiológica e laboral. Palavras-chave: variabilidade da freqüência cardíaca; estresse; pressão sanguínea; obesidade; antropometria; professores.

Background: Sarcopenia is a disease that involves skeletal muscle mass loss and is highly prevalent in the older adult population. Moreover, the incidence of sarcopenia is increased in patients with hypertension. Objectives: The study aimed to evaluate the association between the classes of the drugs used for arterial hypertension treatment and the presence or absence of sarcopenia. Methods: 129 older adults with hypertension were evaluated by the researchers who registered the participants medication for arterial hypertension treatment. Sarcopenia level was measured by anthropometric parameters, muscular strength, and functional capacity. The data were analyzed by one-way ANOVA followed by post-hoc test and Fisher’s exact test; statistical significance was set at 0.05. Results: Age was not different between women with different levels of sarcopenia, but significant differences were observed between men with absent sarcopenia (66.8±4.2 years) and men with probable sarcopenia (77.0±10.2 years). Individuals with absent sarcopenia showed higher handgrip strength (men: 33.8±7.4, women: 23.2±4.6 Kgf) in comparison with those with sarcopenia (men with probable sarcopenia: 9.5±3.3 Kgf, women with probable, confirmed, and severe sarcopenia: 11.7±2.5, 12.2±3.0, 11.8±1.8 Kgf, respectively). The analysis showed an association between the type of medication and degree of sarcopenia; diuretics were significantly associated with probable sarcopenia, and angiotensin II receptor blockers (alone or in combination with diuretics) was associated with absence of sarcopenia. Conclusion: In conclusion, handgrip strength was a good method to diagnose sarcopenia, and diuretics were associated with increased risk of sarcopenia in older adults with hypertension.

This study is aimed at evaluating the profile of inflammatory markers and components of redox regulation in untrained women after 10 weeks of resistance training using equalized protocols but different muscle action duration (MAD). Twenty-two women underwent progressive resistance training exercising the knee extensor muscles for 10 weeks—3x/week, with 3-5 sets of 6 repetitions at 50% of the 1 repetition maximum strength test (1RM), with a rest of 180 s between the series, following the training protocol (i) 5 s of concentric muscle action for 1 s of eccentric muscle action (5C-1E) and (ii) 1 s of concentric muscle action for 5 s of eccentric muscle action (1C-5E). Quadriceps muscle hypertrophy maximum strength (1RM) and redox regulation/muscle damage/inflammatory markers (CAT, SOD, TBARS, FRAP, CH, LDH, CXCL8, and CCL2) were evaluated. Plasma markers were evaluated before and 30 minutes after the first and last training sessions. A similar gain in hypertrophy and maximum strength was observed in both groups. However, in the 5C-1E, a significant major effect was observed for SOD ( F 1.19 = 10.480 , p = 0.004 ) and a significant major time effect, with a reduction in the last training session, was observed for CXCL8 ( F 1.37 = 27.440 , p < 0.001 ). In conclusion, similar protocols of resistance training, with different MAD, produced similar inflammatory and adaptive responses to strength training. As the training load is progressive, the maintenance of this inflammatory and redox regulation profile suggests an adaptive response to the proposed strength training.

A seleção recorrente em espécies autógamas consiste em um procedimento que pode aumentar a probabilidade de combinações genotípicas superiores, em virtude do aumento da frequência de alelos favoráveis. Entretanto, trata-se de uma prática de difícil execução, principalmente devido ao fato de a etapa de recombinação quase sempre ter de ser manual. Suas dificuldades inerentes demandam a busca por metodologias que aumentem sua eficiência. A seleção assistida por marcadores moleculares pode contribuir nesse sentido, uma vez que quase sempre algum desequilíbrio de ligação é restabelecido em cada ciclo seletivo, em decorrência do uso frequente de unidades de seleção com algum grau de endogamia. Para tanto, é fundamental a estimação da proporção da variância genética explicada por marcadores moleculares (p), se um índice de seleção for utilizado, combinando as informações fenotípica e molecular. Embora o coeficiente de determinação (R2) seja por vezes empregado para esse fim, não é claro sob quais circunstâncias esta estatística é adequada, e se não haveria outros estimadores mais apropriados. Face aos aspectos levantados, este trabalho teve por objetivos: a) a obtenção de um estimador da proporção da variância genética explicada por marcadores moleculares, e a avaliação de algumas de suas propriedades e de sua utilização na seleção assistida por marcadores; e b) a avaliação da seleção assistida por marcadores moleculares em espécies autógamas, mediante simulação em computador, sob diferentes valores de parâmetros genéticos e de outros fatores. Um estimador da proporção p da variância genética explicada por marcadores moleculares foi obtido considerando situações em que modelos de regressão múltipla são utilizados, tendo o número de cópias de um dos alelos de vários locos marcadores como variáveis regressaras. Também considerou-se como variável dependente a média fenotípica de progênies avaliadas em experimentos com repetições. Para a avaliação da seleção assistida por marcadores em plantas autógamas, linhagens endogâmicas foram simuladas, em número de 5 (na maioria das situações), cada qual participando de dois cruzamentos mediante um esquema de dialelo circulante, formando assim uma população-base composta por 5 subpopulações. Em cada uma destas, 400 plantas So ou S2 eram classificadas quanto ao genótipo de 130 locos marcadores codominantes, ao longo de um genoma fictício de 10 Morgans. Neste genoma, 50 QTL's foram dispostos aleatoriamente, apresentando efeito diferenciado. As progênies obtidas daquelas plantas So ou S2 eram dispostas em 2 repetições. Os descendentes obtidos por autofecundação das progênies selecionadas formavam novas 5 subpopulações em um ciclo seletivo seguinte. Ao todo, 6 ciclos de seleção foram simulados em 10 repetições, para cada conjunto de valores para parâmetros possivelmente influentes. A seleção assistida por marcadores foi praticada mediante o índice de seleção de Lande & Thompson (1990), e avaliada comparando-a com a seleção baseada apenas nas médias fenotípicas das progênies. Para quantificar o nível de desequilíbrio de ligação em um dado ciclo seletivo, foram considerados todos os pares de locos marcadores distanciados de 16,67 cM apresentando polimorfismo, tomando-se o valor médio do desequilíbrio. Quando o número de progênies é pequeno (da ordem de 10), tanto o estimador proposto da proporção da variância genética explicada por marcadores moleculares, como o coeficiente de determinação, mostraram-se insatisfatórios, devido à sua tendenciosidade ou baixa precisão. Por outro lado, se a herdabilidade da característica for alta, ou tanto este parâmetro como p forem altos, o coeficiente de determinação R2 mostrou-se mais apropriado. Se o número de progênies avaliadas for alto (algumas centenas), o estimador proposto tem um vício consideravelmente menor que o de R2, e com um nível de precisão tolerável. Nesses casos, intervalos de confiança para p podem ser construídos utilizando a aproximação normal. Os resultados de uma forma geral não atestaram a seleção assistida por marcadores como eficiente, por mais de um único ciclo seletivo, em todas as situações consideradas. A razão principal dessa falta de eficiência foi tida principalmente pelo fato de que, ao contrário de estudos anteriores, nos quais foram consideradas populações-base formadas a partir do cruzamento de duas linhagens endogâmicas apenas, nesse estudo optou-se pela simulação de uma população-base formada a partir de várias linhagens. Isto fez com que ocorressem misturas de diferentes fases de ligação entre locos marcadores e aqueles controladores da característica em questão, diminuindo o nível de desequilíbrio de ligação ao longo dos ciclos seletivos, apesar do uso de unidades de recombinação endogâmicas. Quando considerada por apenas um ciclo seletivo, a seleção assistida por marcadores mostrou-se eficiente, especialmente se praticada em gerações precoces de autofecundação, e quando a característica apresentou baixa herdabilidade. O tamanho das subpopulações nas quais a metodologia foi aplicada afetou sobremaneira sua eficiência, demandando a avaliação de algumas centenas de progênies por cruzamento. A técnica mostrou-se promissora no primeiro ciclo seletivo, mesmo em presença de dominância positiva completa. O uso de 200 locos marcadores, ao invés de 130, propiciou melhorias apenas modestas de eficiência. Baixos valores do coeficiente de heterogeneidade de solo de Smith (1938), com consequentes reduções na herdabilidade, também não aumentaram sobremaneira a eficiência do uso de marcadores moleculares. Para que a seleção assistida por marcadores se mantivesse eficiente por mais de um ciclo seletivo, testou-se o uso de seleção de apenas uma progênie por cruzamento (e, consequentemente, apenas duas progênies para compor subpopulações, em ciclos seguintes). Este procedimento de fato aumentou o desequilíbrio de ligação gerado na etapa de recombinação, mas mostrou-se inadequado a longo prazo, devido à ocorrência de alta deriva genética, tanto em QTL's como em locos marcadores, reduzindo o nível de polimorfismo. O uso de um alto tamanho efetivo populacional, pelo uso de 20 linhagens para compor a população-base, não foi suficiente para contornar o problema da deriva genética, evidenciando a dificuldade de se estabelecer um programa de melhoramento em espécies autógamas com características tais que a seleção assistida por marcadores se justifique. Recurrent selection in cultivated autogamous species is a procedure that can enlarge the probability of obtaining superior genotypes, by increasing the frequencies of favorable genes. However, the practice is difficult to be carried out mainly because recombination generally needs to be made manually. These inherent difficulties require the search for methodologies to enhance its efficiency. This can be partly achieved through marker-assisted selection, since almost certainly some level of linkage disequilibrium will be restored, at every cycle of selection, when inbred lines are used as selection units. ln marker-assisted selection, the estimation of the proportion of the genetic variance explained by molecular markers (p) is imperative, when a selection index, combining both phenotypic and molecular information, is used. The coefficient of determination (R2) is sometimes taken for this purpose, but it is not clear under which circumstances this statistic is suitable, and whether there are better estimators. Considering these points, the main objectives of this work were: a) to obtain an estimator of the proportion of the genetic variance explained by molecular markers, and to evaluate its properties and its use in marker-assisted selection; b) to evaluate marker-assisted selection in autogamous species through computer simulation, assuming different genetic and non-genetic parameters conditions. An estimator of the proportion of genetic variance explained by molecular markers was obtained considering a multiple regression model, in which the numbers of one of the alleles, at several marker toci, are the regressor variables. The dependent variable was the phenotypic mean of progenies evaluated in replicated trials. The evaluation of marker-assisted selection in autogamous species was performed by simulating 5 inbred tines (in most of the situations considered), each crossed with two others, in a circulant diallel scheme, such that a base population of 5 crosses was formed. Within each cross, 400 So or S2 plants were genotyped in relation to 130 marker Ioci, spread over a genome of 10 Morgans. ln this genome, 50 QTL of different effects were located randomly. Progenies derived from those So or S2 plants were replicated twice, and evaluated with respect to the simulated trait. The descendants of the selected progenies formed 5 new subpopulations in a next selective cycle. For each situation, 6 cycles were simulated in 10 replications. The index proposed by Lande & Thompson (1990) was applied for marker-assisted selection and its efficiency measured by comparing the average progress attained with that found assuming selection based solely on phenotypic progeny means, for the simulated trait. The level of linkage disequilibrium in a given cycle was quantified by the average value observed in all pairs of polimorfic marker loci, 16.67cM distant of one another. The proposed estimator of the proportion of genetic variance explained by molecular markers, and the coefficient of determination, were both unsatisfactory with small numbers of progenies (about 10), due to strong bias and/or low precision. However, if heritability of the trait is high, or both heritability and p are high, then the coefficient of determination R2 showed to be more suitable. lf the number of evaluated progenies is large (as a few hundreds), the proposed estimator was less biased than R2, and had an acceptable precision. Under these circumstances, confidence intervals for p can be constructed based on approximations to the normal distribution. Results in general showed that marker-assisted selection is not efficient, after the first cycle of selection, for all situations considered. These results are not in agreement with previous reports on computer simulation of marker assisted selection. The reason for this contrast must have been that, while in most of other works the base population was constructed by crossing only two inbred lines, in this study the base population was formed by intercrossing several inbred lines. This caused a mixture of different gametic phases between marker loci and quantitative trait loci, thus reducing the amount of linkage disequilibrium, in advanced cycles, despite the use of inbred selection units. When considering a single cycle of selection, marker-assisted selection showed to be efficient, specially if practiced in early generations of inbreeding, and under low heritability. The size of the population strongly affects its efficiency, requiring the evaluation of some hundreds of progenies. The technique was promising in a single cycle of selection even in the presence of complete positive dominance. The use of 200 marker loci yielded only slight improvement in efficiency, in relation to 130 marker loci. Low values of the coefficient of soil heterogeneity of Smith (1938), which lowered heritability, did not markedly increase the efficiency of marker-assisted selection, either. ln order to search for situations in which marker-assisted selection could be effective in subsequent cycles, the selection of a single progeny per cross was also simulated. This led to the formation of subpopulations consisting of only two inbred lines, in all cycles, and a consequent increase of linkage disequilibrium in the recombination process. In spite of this, the effectiveness of marker-assisted selection was not improved in a long term basis, mainly due to genetic drift that was detected not only for QTL's but for marker loci as well, thus reducing the degree of polymorphism. lncreasing effective population size through a large number (20) of inbred lines to form the base population was not sufficient for reducing the effect of drift. These results clearly showed that finding the ideal situations for marker-assisted selection to be effective in autogamous species is a difficult task.

Strength exercise is a strategy applied in sports and physical training processes. It may induce skeletal muscle hypertrophy. The hypertrophy is dependent on the eccentric muscle actions and on the inflammatory response. Here, we evaluate the physiological, immunological, and inflammatory responses induced by a session of strength training with a focus on predominance of the eccentric muscle actions. Twenty volunteers were separated into two groups: the untrained group (UTG) and the trained group (TG). Both groups hold 4 sets of leg press, knee extensor, and leg curl at 65% of personal one-repetition maximum (1RM), 90 s of recovery, and 2″conc/3″eccen of duration of execution in each repetition. Blood samples were collected immediately before and after, 2 hours after, and 24 h after the end of the exercise session. The single session of strength training elevated the heart rate (HR), rating of perceived exertion (RPE), visual analog scale (VAS), and lactate blood level in UTG and TG. Creatine kinase (CK) levels were higher at 2 and 24 h after the end of the exercise in UTG and, in TG, only at 24 h. The number of white blood cells (WBC) and neutrophils increased in UTG and TG, post and 2 h after exercise. Lymphocytes increased postexercise but reduced 2 h after exercise in both groups, while the number of monocytes increased only immediately after the exercise session in UTG and TG. The strength training session elevated the levels of apelin and fatty acid-binding proteins-3 (FABP3) in both groups and brain-derived neurotrophic factor (BDNF) in TG. The single exercise session was capable of inducing elevated HR, RPE, lactate level, and CK levels. This protocol changed the count/total number of circulating immune cells in both groups (UTG and TG) and also increased the level of plasmatic apelin, BDNF, and FLTS1 only in TG and FABP3 myokines in both groups.

Although fish is a healthy alternative for meat, it can be a vehicle for mercury (Hg), including in its most toxic organic form, methylmercury (MeHg). The objective of the present study was to estimate the risk to human health caused by the consumption of sushi and sashimi as commercialized by Japanese food restaurants in the city of Campinas (SP, Brazil). The total Hg content was determined by atomic absorption spectrometry with thermal decomposition and amalgamation, and the MeHg content calculated considering that 90% of the total Hg is in the organic form. The health risk was estimated from the values for the provisional tolerable weekly ingestion (PTWI) by both adults and children. The mean concentrations for total Hg were: 147.99, 6.13, and 3.42 µg kg

In order to reduce the degradation of naturally-occurring components by conventional heat treatment, alternative processing techniques have been studied to preserve the nutritional properties of processed foods, such as thermosonication. This study evaluates the application of thermosonication for the inactivation of pathogenic microorganisms, and its effect on antioxidant activity and retinol level in donated human milk. We evaluate the effect of thermosonication on Staphylococcus aureus, Escherichia coli, and Salmonella spp. microorganisms in human milk by analyzing the effect of time and temperature of the thermosonication on these microorganisms using a central composite rotatable design. Also evaluated the effects of thermosonication (60 °C/4 min) on antioxidant activity using DPHH (2, 2-diphenyl-1-picrylhydrazyl) free radical and ABTS (2,2′-azino-bis 3- ethylbenzothiazoline-6-sulfonic acid) scavenging methods and on the retinol level in human milk and compared them to the effects of holder pasteurization (62.5 °C/30 min) in vitro. For this evaluation, a pool of the 10 human milk samples was made and distributed 40 mL, from this pool, for two interventions (holder pasteurization and thermosonication) and one control (untreated milk). Both in thermosonication and non-ultra-sound heat treatments, the microorganism counts tended to remain stable at lower temperatures, with the most significant and continuous reductions in thermosonication observed at the points of inflexion of the curves of the adjusted models: at 53.7 °C, 52.0 °C, and 60.9 °C for S. aureus, E. coli, and Salmonella, respectively. Thermosonication also promoted greater decimal reductions of the microorganisms analyzed than heat treatment at 60 °C, 48 °C, and 65 °C for S. aureus, E. coli, and Salmonella, respectively. Holder pasteurization significantly reduced the antioxidant activity when compared to the control, while thermosonication increased it. Retinol level remained stable following both pasteurization and thermosonication. This study could be used to encourage further studies to fill in the remaining gaps for this type of processing on human milk.

The high fat diet (HFD) can trigger metabolic and cardiovascular diseases. Trypanosoma cruzi infection induces progressive inflammatory manifestations capable to affect the structure and the function of important organs such as the heart and liver. Here we aimed to investigate the effects of a HFD on the immune response and matrix metalloproteinase (MMP) activities during acute infection with the T. cruzi strain VL-10. The VL-10 strain has cardiac tropism and causes myocarditis in mice. Male C57BL/6 mice were treated with either: (i) regular diet (Reg) or (ii) HFD for 8 weeks, after which mice in each group were infected with T. cruzi. Mice were euthanized on day 30 after infection, and the liver and heart were subjected to histology and zymography to determine MMP-2 activities and plasma levels of IL-10, TNF, CCL2, and CCL5. T. cruzi-infected HFD animals had higher parasitemia, LDL and total cholesterol levels. Regardless of diet, plasma levels of all inflammatory mediators and cardiac MMP-2 activity were elevated in infected mice in contrast with the low plasma levels of leptin. HFD animals presented micro- and macrovesicular hepatic steatosis, while cardiac leukocyte infiltration was mainly detected in T. cruzi-infected mice. Our findings suggested that a HFD promotes higher circulating T. cruzi load and cardiac and liver immunopathogenesis in an experimental model using the VL-10 strain of the T. cruzi.

Psychotria viridis is one of the species that produces N,N-dimethyltryptamine. Its decoction together with other species, such as Banisteriopsis caapi, produces ayahuasca, a beverage used for ritualistic and medicinal purposes. The goal of this study was to understand how environmental factors and cultivation methods influenced the content of N,N-dimethyltryptamine in P. viridis. Over all four seasons, leaf samples were collected from 25 different locations in 14 Brazilian states, and Federal District. Environmental parameters, micro and macronutrients, plant characteristics, information on farming methods were correlated with N,N-dimethyltryptamine content, determined by gas chromatography coupled to mass spectrometry (GC-MS). Greatest effects on the N,N-dimethyltryptamine amount were associated with seasonality, altitude, latitude and biome type. A positive correlation between N and Mg content and N,N-dimethyltryptamine levels was statistically established. By regression analysis, the adequate foliar nutrient levels that would result in the concentration of N,N-dimethyltryptamine in cultivated plants similar to that of Amazonian P. viridis were equated.

The impact of soapstone (steatite) upon inorganic element contaminant concentrations in alcoholic beverages was investigated. Concentrations of As, Cd, Cu, Ni and Pb levels in 8 Brazilian spirits plus an alcoholic simulant were initially measured, and then measured following each 24 h cycle of exposure to raw soapstone cups, for a total of 4 cycles/sample. The results were compared to the levels established by Brazilian and German regulations. The contact between the spirits and the soapstone reduced the Cu content by up to 50.4% and increased the Ni content by up to 622.2%, especially in the first contact cycle. The exposure of spirits to the soapstone exhibits a linear reduction in the Pb content (18.3–54.5%) while As and Cd levels remained unaltered throughout the experiments. In conclusion, crude soapstone in contact with alcoholic solutions acts as an adsorbent of trace elements (Cu and Pb) while releasing Ni.

Uma estratégia comum em programas de melhoramento é conduzir estudos básicos de herança para investigar a hipótese de controle do caráter por um ou poucos genes de efeito principal, associados ou não a genes modificadores de pequeno efeito. Neste trabalho, foi utilizada a inferência bayesiana para ajustar modelos de herança genética aditiva-dominante a experimentos de genética vegetal com várias gerações. Densidades normais com médias associadas aos efeitos genéticos das gerações foram consideradas em um modelo linear em que a matriz de delineamento dos efeitos genéticos tinha coeficientes indeterminados (precisando ser estimada para cada indivíduo). A metodologia foi ilustrada com um conjunto de dados de um estudo de herança da partenocarpia em abobrinha (Cucurbita pepo L). Tal ajuste permitiu explicitar a distribuição a posteriori das probabilidades genotípicas. . A análise corrobora resultados anteriores da literatura, porém foi mais eficiente que alternativas prévias que supunham a matriz de delineamento conhecida para as gerações. Conclui-se que a partenocarpia em abobrinha é governada por um gene principal com dominância parcial. A common breeding strategy is to carry out basic studies to investigate the hypothesis of a single gene controlling the trait (major gene) with or without polygenes of minor effect. In this study we used Bayesian inference to fit genetic additive-dominance models of inheritance to plant breeding experiments with multiple generations. Normal densities with different means, according to the major gene genotype, were considered in a linear model in which the design matrix of the genetic effects had unknown coefficients (which were estimated in individual basis). An actual data set from an inheritance study of partenocarpy in zucchini (Cucurbita pepo L.) was used for illustration. Model fitting included posterior probabilities for all individual genotypes. Analysis agrees with results in the literature but this approach was far more efficient than previous alternatives assuming that design matrix was known for the generations. Partenocarpy in zucchini is controlled by a major gene with important additive effect and partial dominance.

The direct sowing to tropical forest restoration can be viable when the ecological and silvicultural aspects of species areknown. This work evaluated the effect of breaking seed dormancy and a physical protector on the initial growth of riparian treespecies. The experiment was carried out in a randomized blocks design, in a factorial (2x2), with four blocks and four plots for eachtreatment. The treatment to break seed dormancy used were: immersion in sulphuric acid for 20 minutes and washing in water for 1hour plus soaking for 24 hours for Trema micrantha; immersion in boiling water (100oC) with following soaking until refreshing for24 hours to Senna multijuga and Senna macranthera and pre-soaking in water for 2 hours for Solanum granuloso-leprosum. Thephysical protector used was a transparent plastic cup (500mL). The breaking seed dormancy used was efficient in laboratory, exceptfor S. macranthera. In field conditions, it was efficient only for S. multijuga and S. macranthera. The physical protector did notpresented any benefit for the studied tree species regarding seedlings emergence and survival, but it provided significant differencesin height and base diameter for S. multijuga and in height for S. macranthera after three months. After 24 months, T. micranthapresented the highest values for height and basal diameter. S. macranthera presented the height relative growth and T. micrantha thehighest basal diameter. The studied species can be recommended for ecological forest restoration, using direct sowing.

QTL mapping consists of estimating the position and effects of genes (or linkage groups) that control quantitative traits. For traits that follow a normal distribution of probability, statistical approaches for QTL mapping are described in literature. However, for other traits the amount of research is little. The present work aimed to evaluate four alternative methods for QTL mapping of genes that control Poisson traits. The studied approaches were: standard interval mapping methodologies of Lander and Botstein and of Haley and Knott, a mixed model based on Poisson distributions, and a generalized linear model. Through computational simulation, the results showed great similarity for the different approaches under study. All approaches were highly effective for the tested simulations, especially when the abnormality of data in use was taken into account. Owing to the computational simplicity, Harley and Knott's methodology was considered most effective.

A separation of the effects of major genes from effects of polygenes is important to understand genetic inheritance of quantitative traits and predict the segregation of a crossing. The inheritance mode of resistance to anthracnose leaf bligh t (ALB) caused by C. graminicola was evaluated by a mixed model. P 1, P2, F1, F2, BC1, and BC2 generations derived from four crossings between tropical maize inbred lines were used. Maximum likelihood was used to choose the best fitting inheritance model and to estimate genetic parameters. The mixed model indicated that the resistance to ALB was controlled by a major gene in all crosses and trials, and by polygenes in at least one trial. Additive and dominance effects were important for both major gene and polygenes. Both effects of the major genes were negative, indicating their contribution to disease resistance, while both effects of the polygenes were positive or negative, reflecting differences in the genetic background among inbred li nes.

The influence of a population of the understorey woody bamboo Merostachys riedeliana and different flooding regimes on tree community dynamics in a section of tropical semideciduous forest in South-Eastern Brazil was examined. A forest section with an area of 1.6 ha composed of 71 adjacent plots was located on a slope ending at the river margin. The section was divided into five topographical sectors according to the mean duration of river floods. In 1991 and 1998 all trees with a diameter at the base of the trunk ≥ 5 cm were measured, identified and tagged, and all live bamboo culms were counted. Annualised estimates of the rates of tree mortality and recruitment, gain and loss of tree basal area, and change in bamboo density were calculated for each of the 71 plots and five topographical sectors as well as for diameter classes and tree species. To segregate patterns arising from spatially autocorrelated events, geostatistical analyses were used prior to statistical comparisons and correlations. In general, mortality rates were not compensated by recruitment rates but there was a net increase in basal area in all sectors, suggesting that the tree community as a whole was in a building phase. Tree community dynamics of the point bar forest (Depression and Levee sectors) differed from that of the upland forest (Ridgetop, Middle Slope and Lower Slope sectors) in the extremely high rates of gain in basal area. The predominant and specialised species, Inga vera and Salix humboldtiana, are probably favoured by relaxed competition in an environment stressed by long-lasting floods. In the upland forest, mortality rates were highest at the Middle Slope, particularly for smaller trees, while recruitment rates were lowest. As bamboo clumps were concentrated in this sector, the locally higher instability in the tree community probably resulted from the direct interference of bamboos. The density of bamboo culms in the upland forest was negatively correlated with the rates of tree recruitment and gain in basal area, and positively correlated with tree mortality rates. Bamboos therefore seemed to restrict the recruitment, growth and survival of trees.

Curvas de lactação representam a produção de leite de uma fêmea leiteira em função do tempo. Uma vez que tais curvas variam aleatoriamente de animal para animal, devido a fatores tanto genéticos quanto ambientais, o modelo misto conhecido como regressão aleatória é apropriado para ajustar os dados de produção de um rebanho. A regressão aleatória foi avaliada neste estudo mediante simulação de dados. Produções de cinco animais em cinco idades foram simuladas em mil conjuntos de dados independentes, em três níveis de precisão, ou seja, a razão entre a variância de regressão e a total igual a 0,9 (variância alta), 0,5 (variância média) e 0,1 (variância baixa) e três graus médios de parentesco entre os animais. A regressão aleatória foi utilizada de duas maneiras, admitindo-se ou não que as variâncias genéticas e de meio fossem conhecidas, comparando-a com o método de quadrados mínimos ordinário. Pelos resultados pode-se concluir que, com baixa precisão, os modelos tiveram comportamento semelhante quanto ao erro quadrático médio e desvios absolutos médios. O nível de precisão foi o fator mais influente do que o grau de parentesco no desempenho relativo dos modelos. De maneira geral, a regressão aleatória com variâncias conhecidas propiciou predições mais precisas, seguida da regressão aleatória estimando-se tais variâncias. Concluiu-se que a regressão aleatória é potencialmente útil sob condições de alta variabilidade ambiental relativa, mesmo com variâncias desconhecidas. Lactation curves represent milk production of a dairy dam as a function of time. Since such curves vary randomly among individuals, due to environment and genetic factors, the mixed model known as random regression is suitable for fitting such curves, and it was evaluated in this study through data simulation. Milk production of five animals in five ages was simulated in one thousand random and independent data sets, considering three precision levels, variation due to the model in relation to the residual variation of 0,9 (high variance), 0,5 (medium variance) and 0,1 (low variance) and three average degrees of relationship. Random regression was used in two ways, admitting or not that the variances of the model (genetic and of environment) were known, and compared to the ordinary least squares method. Results showed that, under low variance, the models had similar fits, with regard mean square error and mean absolute deviation. The level of precision was more influential than the degree of relationship on relative performance of models. In general, random regression with known variances yielded the most precise predictions, followed by random regression estimating such variances. Results suggest that random regression is potentially useful under high environmental heterogeneity, even if variances are unknown.

Cytotaxonomic studies were carried out on 26 accessions of Pennisetum spp. originating from the Active Germplasm Bank of Embrapa Gado de Leite-Juiz de Fora, Minas Gerais, Brazil.This study presents cytogenetics and reproductive morphological data for each one of these accessions, which allowed groupings and suggest botanical identifications to be established. The metaphases of the accessions characterized as P. purpureum confirmed the presence of 2n = 28 chromosomes that have already been described for this species. For the hybrids between P. purpureum and P. glaucum and for the hexaploids, resulting from the chromosome duplication of these hybrids, 2n = 21 and 2n = 42 chromosomes were confirmed, respectively. The wild accession identified as P. setosum showed metaphases with 2n = 54 chromosomes, while those characterized as P. nervosum had cells with 2n = 36 chromosomes. The wild accession 15 was different from the others for the morphological characters, with 2n = 36 chromosomes, and was classified as P. orientale. Two statistical procedures were used (canonical variables and cluster analysis on the basis of the Mahalanobis distance), and the results confirmed the conclusions obtained from the cytogenetic and morphologic analysis.

O índice I de Moran é a ferramenta usual para se medir a intensidade da autocorrelação espacial em dados de marcadores genéticos. A estatística I é assintoticamente normalmente distribuída, podendo ser avaliada como desvios da normal padrão mediante o suposto-N (aproximação normal). Porém, para pequenos números de populações (m25}, deve-se aplicar o teste de Mantel em qualquer das situações simuladas. Moran's I index is the usual tool to measure the intensity of the spatial autocorrelation in genetic markers data. I statistics is asymptotically normally distributed and it may be evaluated as standard normal deviations (assumption-N, normality). However, for small numbers of populations (m

The inheritance of the tendency to set parthenocarpic fruit in the summer squash (Cucurbita pepo L.) line Whitaker was studied. Two parental lines, Whitaker (parthenocarpic) and Caserta (non-parthenocarpic), and the F1 and F2 generations and backcrosses to both parents were tested. The parthenocarpic tendency of individual plants was scored on a scale from 1 (non-parthenocarpic fruit) to 5 (parthenocarpic fruit). The Whitaker line produced parthenocarpic fruit and had a mean score of 4.2, whereas Caserta did not set parthenocarpic fruit and had a score of 1.55. The heritability estimates indicated that genetic gains from selection were feasible. The additive-dominant model showed a good fit, with epistasis being negligible or nonexistent. The hypothesis of monogenic inheritance with incomplete dominance was not rejected within the degree of dominance range from 0.2 to 0.5. These results indicate that parthenocarpy is controlled by a single locus, with incomplete dominance in the direction of parthenocarpic expression.

Uma das dificuldades de se conduzir estudos citogenéticos em espécies vegetais nativas do cerrado é a ocorrência de baixos índices metafásicos no meristema radicular. O incremento dos índices mitótico e metafásico em células de pontas de raiz tem sido obtido em várias espécies com a sincronização do ciclo celular por meio de hidroxiuréia (HU). Neste trabalho foram determinadas as condições ótimas para a sincronização eficiente do ciclo em células meristemáticas de raízes de baru (Dipteryx alata Vog.). Foram testadas quatro concentrações de HU (0,00; 1,25; 2,50; 5,00 e 10,00 mM), três tempos de exposição das raízes (10, 15 e 20 h) e dois tempos de recuperação do ciclo (5 e 10 h). As melhores respostas foram obtidas com exposição das raízes, de cerca de 1 cm, à solução de HU 3,5 mM, por 20 horas, com posterior recuperação do ciclo em água destilada por 5 horas. O índice de 45% de células em divisão representou um incremento de cerca de 5 vezes em relação à testemunha, ao passo que para células em metáfases, o índice de 22,6% foi cerca de 10 vezes superior. Portanto, o uso dessa estratégia mostrou-se bastante eficiente para a obtenção de grande quantidade de cromossomos para análise citogenética do baru. A major difficulty in cytogenetic studies of plant species from "cerrado" is the low metaphasic index in root tip cells. Cell cycle synchronization, by using hydroxyurea (HU), has been successfully used in order to obtain high mitotic and metaphasic index in several species. The goal of this work was to optimize conditions for efficient synchronization of Dipteryx alata root tip meristematic cells. Different levels of hydroxyurea (0, 1.25, 2.50, 5.00, and 10.00 mM), periods of treatment (10, 15, and 20 h) and periods of cell cycle recovery (5 and 10 h) were tested. Best results were achieved by treating 10-mm long roots with 3.5 mM hydroxyurea, for 20 h and incubating for 5 h in distilled water. The amount of cells dividing was five folds increased, compared to that of the control treatment, reaching an index value of 45%. Whereas for metaphase cells, the index value of 23% was 10 times higher. Therefore, such strategy was efficient to obtain high chromosome amounts for cytogenetic analysis of baru.

The augmented block design is widely used in breeding programs, with non-replicated treatments generally being selection units, and replicated treatments being standard cultivars. Originally, an intrablock analysis (fixed model) was proposed. Although non-replicated treatments and/or blocks can be considered of random nature, mixed linear models could be used instead. This work evaluated such an approach, using computer simulation. Populations consisted of sets of randomly generated inbred lines. Molecular marker data were also simulated to allow the estimation of the genetic covariance matrix. Different conditions were considered, varying heritability and the coefficient b of Smith of soil heterogeneity. For each condition 100 simulations were performed, considering four linear models, varying respectively the nature of the effects of blocks and non-replicated treatments (fixed - F, or random - R): FF, FR, RF and RR. In relation to FF, the mixed models were more efficient under low to intermediate heritability and high b. Mixed models could improve inference in breeding programs using the augmented block design and the choice of the model should rely on the kind of selection. If this is truncated, the RF model should be preferred; if it is not, then the RR model would be more suitable. O delineamento em blocos aumentados é amplamente utilizado em programas de melhoramento, geralmente com tratamentos não-repetidos correspondentes a unidades de seleção, e tratamentos repetidos sendo cultivares comerciais. Originalmente, uma análise intrablocos (modelo fixo) foi sugerida. No entanto, se os tratamentos não-repetidos e/ou blocos puderem ser considerados de natureza aleatória, modelos lineares mistos poderiam ser utilizados. Este estudo objetivou a avaliação de tal abordagem, utilizando simulação. Linhagens endogâmicas foram geradas aleatoriamente, bem como dados de marcação molecular, para estimar a matriz de covariâncias genéticas. Variaram-se a herdabilidade e o coeficiente b de heterogeneidade de solo de Smith; em cada condição, 100 simulações foram feitas, considerando 4 modelos lineares, variando respectivamente a natureza dos efeitos de bloco e de tratamentos não-repetidos (fixo -- F, ou aleatório -- A): FF, FA, AF e AA. Em relação ao modelo FF, os modelos mistos foram mais eficientes especialmente sob herdabilidade baixa a intermediária e alto b. Modelos mistos podem melhorar a inferência em programas de melhoramento utilizando o delineamento, e a escolha do modelo deve se basear no tipo de seleção. Se esta for truncada, o modelo AF deveria ser preferido; se não for, então o modelo AA é mais apropriado.

Estimation of the proportion of genetic variance explained by molecular markers (p) plays an important role in basic studies of quantitative traits, as well as in marker-assisted selection (MAS), if the selection index proposed by Lande and Thompson (Genetics 124: 743-756, 1990) is used. Frequently, the coefficient of determination (R2) is used to account for this proportion. In the present study, a simple estimator of p is presented, which is applicable when a multiple regression approach is used, and progenies are evaluated in replicated trials. The associated sampling distribution was obtained and compared with that of R2. Simulations indicated that, when the number of evaluated progenies is small, the statistics are not satisfactory, in general, due to bias and/or low precision. Coefficient R2 was found adequate in situations where p is high. If a large number of progenies is evaluated (say, a few hundreds), then the proposed estimator appears to be better, with acceptable precision and considerably lower bias than R2. A normal approximation to the sampling distribution of is given, using Taylor's expansion of the expectation and variance of this statistic. Approximate confidence intervals for p, based on normal distribution, are reasonable, if the number of progenies is large. The use of in MAS is illustrated for estimation of the weight given to the molecular score, when a selection index is used.A estimação da proporção da variância genética explicada por marcadores moleculares (p) desempenha um importante papel em estudos básicos de características quantitativas, bem como na seleção assistida por marcadores (SAM), se o índice de seleção proposto por Lande e Thompson (Genetics 124: 743-756, 1990) é utilizado. Freqüentemente, o coeficiente de determinação (R2) é usado para quantificar esta proporção. Neste trabalho, um estimador simples de p é apresentado, o qual é aplicável quando um modelo de regressão múltipla é utilizado e progênies são avaliadas em delineamentos experimentais. A sua distribuição de amostragem foi obtida e comparada com aquela do R2. Simulações de Monte Carlo sugeriram que, quando o número de progênies avaliadas é pequeno, ambas as estatísticas são insatisfatórias, devido a tendenciosidades e/ou baixa precisão. O coeficiente R2 mostrou-se adequado apenas quando p é alta. Se o número de progênies avaliadas é elevado (algumas centenas), então o estimador proposto mostrou-se superior, com tendenciosidade consideravelmente menor que a do R2, e com precisão aceitável. Uma aproximação normal da distribuição de amostragem de foi obtida, utilizando a expansão de Taylor da esperança e da variância dessa estatística. Intervalos de confiança aproximados para p, baseados na distribuição normal, mostraram-se satisfatórios, se o número de progênies for elevado. O uso de na SAM é ilustrado para a estimativa do coeficiente dado ao escore molecular, se um índice de seleção é utilizado.

Estudos de heranca genetica em plantas sao realizados para caracterizar os efeitos geneticos e verificar a existencia de um gene de efeito maior e/ou de genes de pequeno efeito (“poligenes”). Quando a caracteristica de interesse e continua, a verossimilhanca e baseada em modelos de misturas de densidades normais. Uma vez que nao ha testes exatos evidentes para julgar a existencia de um gene de efeito maior, a razao de verossimilhanca generalizada e em geral utilizada, considerando a aproximacao de qui-quadrado. Este trabalho objetivou avaliar esta estatistica de teste atraves de simulacao em computador. Dados foram simulados, considerando particularidades de genealogia tipicas de tais estudos, e duas condicoes sob a hipotese de nulidade, ou seja, sem a presenca de um gene de efeito maior e sem a presenca de genes de pequeno efeito (poligenes), para avaliar o controle do erro tipo I. O poder do teste foi avaliado com ambos presentes. No processo de simulacao, foram variados o tamanho de amostra e valores do coeficiente de herdabilidade. Resultados indicaram que, embora a distribuicao empirica da razao de verossimilhanca tenha se desviado significativamente da distribuicao de qui-quadrado, houve controle do erro tipo I, considerando um nivel de significância nominal de 5%. O poder e elevado para detectar poligenes e gene de efeito maior, em geral. O poder e baixo para detectar gene de efeito maior quando a proporcao da variacao genetica explicada por este e baixa.

Dentre os diversos aspectos geralmente observados na caracterização genética de populações naturais, a avaliação do grau de estruturação da variabilidade genética entre e dentro dos indivíduos e a obtenção de estimativas de parâmetros genéticos indicadores do sistema reprodutivo da espécie assumem grande importância. Os parâmetros de maior interesse neste caso são o índice de fixação intrapopulacional (f) e a taxa de fecundação cruzada (t). Pelo uso de simulações computacionais, este trabalho demonstra o caráter dinâmico do índice de fixação intrapopulacional em diferentes locos ao longo das gerações em decorrência do caráter finito da população e de variação nas taxas médias de fecundação cruzada entre gerações. Sugere-se que este caráter dinâmico representa uma explicação para a elevada variação, comumente reportada na literatura, das estimativas de f obtidas com locos diferentes avaliados em uma mesma população. Utilizando a abordagem Bayesiana, um modelo hierárquico de análise é proposto para a estimação de f, incorporando as informações obtidas de múltiplos locos não ligados, levando-se em conta a condicionalidade do processo de estimação ao polimorfismo dos locos utilizados. O modelo proposto incorpora o caráter dinâmico de f para diferentes locos e permite a estimação do número efetivo de indivíduos reprodutivamente ativos em uma população. Propõe-se ainda um modelo Bayesiano para a estimação da taxa de fecundação cruzada com base na informação de múltiplos locos, admitindo-se a possibilidade de ocorrência de apomixia. Os modelos propostos são avaliados por simulação e exemplos de aplicação a dados reais de marcadores moleculares codominantes são discutidos. Os resultados obtidos demonstram a aplicabilidade das metodologias propostas e o elevado potencial de aplicação da estatística Bayesiana em estudos de genética de populações. Among the various aspects generally considered in the genetic characterization of natural populations of plant species, the evaluation of the degree of genetic structure within and among individuals and the estimation of parameters related to the species mating system are of great importance. In general, considerable effort is focused on the estimation of the intrapopulation fixation index (f) and the outcrossing rate (t). Using computer simulated data, the dynamic nature of f for different loci along generations is illustrated. The dynamic nature of f is shown to result from the finite condition of populations and from the variation in the mean values of the outcrossing rates among generations. It is suggested that this dynamic behavior explains the inconsistency, commonly reported in the literature, of f estimates obtained for different loci in a given population. Using a Bayesian approach, we propose a hierarchical model for the estimation of f, incorporating information obtained from different unlinked loci and considering the conditionality of the estimation process to genetic polymorphism. The proposed model incorporates the dynamic nature of f values for different loci and allows the estimation of the effective number of reproductively active individuals in a given population. Using a similar approach, a Bayesian model is also proposed for estimating the outcrossing rate using multiple loci information and incorporating the possibility of apomixis. The models proposed are evaluated by computer simulations and examples using real data from codominant molecular markers are presented. Results obtained illustrate the applicability of the proposed methods and reveal the great potential of use of Bayesian statistics in population genetic studies.

O mapeamento de QTL's difere dos demais tipos de pesquisas conduzida em genética. Por se tratar basicamente de um procedimento de testes múltiplos, surge, neste contexto, um problema que se refere ao nível de significância conjunto da análise, e consequentemente, seu poder. Deste modo, avaliou-se, via simulação computacional de dados, o poder de detecção de QTL's da análise de marcas simples, realizada por meio de regressão linear múltipla, utilizando o procedimento stepwise" para seleção das marcas e procedimentos baseados em testes individuais, utilizando os critérios FDR e de Bonferroni para determinação nível de significância conjunto. Os resultados mostraram que o procedimento baseado em regressão múltipla, utilizando o procedimento stepwise" foi mais poderoso em identificar as marcas associadas a QTL's e, mesmo nos casos em que este procedimento apresentou poder ligeiramente inferior aos demais, verificou-se que o mesmo tem como grande vantagem selecionar apenas as marcas mais fortemente ligadas aos QTL's. Dentre os critérios FDR e de Bonferroni, o primeiro mostrou-se, em geral, mais poderoso, devendo ser adotado nos procedimentos de mapeamento por intervalo. Outro problema encontrado na análise de QTL's refere-se µa abordagem da interação QTL's x ambientes. Neste contexto, apresentou-se uma partição da variância da interação genótipos x ambientes em efeitos explicados pelos marcadores e desvios, a partir da qual obtiveram-se os estimadores da proporção da variância genética (pm), e da variância da interação genótipos x ambientes (pms), explicadas pelos marcadores moleculares. Estes estimadores independem de desvios das frequências alélicas dos marcadores em relação µ as esperadas (1:2:1 em uma geração F2, 1:1 em um retrocruzamento, etc.), porém, apresentam uma alta probabilidade de obtenção de estimativas fora do intervalo paramétrico, principalmente para valores elevados destas proporções. Contudo, estas probabilidades podem ser reduzidas com o aumento do número de repetições e/ou de ambientes nos quais as progênies são avaliadas. A partir de um conjunto de dados de produtividade de grãos, referentes µ a avaliação de 68 progênies de milho, genotipadas para 77 marcadores moleculares codominantes e avaliadas em quatro ambientes, verificou-se que as metodologias apresentadas permitiram estimar as proporções pm e pms, bem como classificar as marcas associadas a QTL's, conforme seu nível de interação. O procedimento permitiu ainda a identificação de regiões cromossômicas envolvidas no controle genético do caractere sob estudo conforme sua maior ou menor estabilidade ao longo dos ambientes. In general terms, QTL mapping di®ers from other research ac-tivities in genetics. Being basically a multiple test procedure, problems arise which are related to the joint level of signi¯cance of the analysis, and consequently, to its power. Using computational simulation of data, the power of simple marker analysis, carried out through multiple linear regression, using stepwise procedures to select the markers was obtained. Procedures based on single tests, using both the FDR and the Bonferroni criteria to determinate the joint level of signi¯cance were also used. Results showed that the procedure based on multiple regression, using the stepwise technique, was the most powerful in identifying markers associated to QTL's. However, in cases where its power was smaller, its advantage was the ability to detect only markers strongly associates with QTL's. In comparision with the Bonferroni method, the FDR criterion was in general more powerful, and should be adopted in the interval mapping procedures. Additional problems found in the QTL analysis refer to the QTL x environment interaction. We consider this aspect by par-titioning the genotype x environment interaction variance in components explained by the molecular markers and deviations. This alowed estimating the proportion of the genetic variance (pm), and genotype x environment variance (pms), explained by the markers. These estimators are not a®ected by deviations of allelic frequencies of the markers in relation to the expected values (1:2:1 in a F2 generation, 1:1 in a backcross , etc). However, there is a high probability of obtaining estimates out of the parametric range, specially for high values of this proportion. Nevertheless, these probabilities can be reduced by increasing the number of replications and/or environments where the progenies are evaluated. Based on a set of grain yield data, obtained from the evaluation of 68 maize progenies genotyped for 77 codominant molecular markers, and evaluated as top crosses in four environments, the presented methodologies allowed estimating proportions pm and pms as well the classification of markers associated to QTL's, with respect to its level of genotype x environment interaction. The procedure also allowed the identification of chromosomic regions, involved in the genetical control of the considered trait, according to its stability, in relation to the observed environmental variation.

A presente pesquisa propôs-se a investigar problemas de ordem estatístico-experimental relacionados à aplicação do delineamento de blocos aumentados, em programas de melhoramento genético vegetal. Nesses desenhos experimentais há duas categorias de tratamentos: as testemunhas (repetidas) e os tratamentos adicionais ou novos (normalmente não repetidos). As primeiras usualmente são cultivares comerciais já recomendados, e os outros, os novos materiais genéticos sob avaliação. Sua relação com os delineamentos de blocos em geral, princípios para a sua aplicação e análise estatística, bem como informações correlatas de outros temas aqui investigados (modelos mistos, componentes de variância e análise espacial de experimentos) foram objetos de revisão no Capítulo 1. O material que fundamentou este trabalho foi um conjunto de 41 ensaios de competição de linhagens de soja (genótipos), em gerações de autofecundação nunca inferiores a F5. Os ensaios, assim delineados, fazem parte do Programa de Melhoramento da Soja desenvolvido pelo Setor de Genética Aplicada às Espécies Autógamas, do Departamento de Genética da ESALQ/USP. Foram escolhidos, preferencialmente, os ensaios que dispunham de mapa de campo completo, o que possibilita associar cada observação à sua posição espacial na área do experimento. Entre os diversos caracteres avaliados, apenas os dados de produtividade de grãos (kg/ha) foram aqui considerados. Sabe-se que esses ensaios são conduzidos em etapas preliminares, quando as linhagens podem ser estatisticamente assumidas como de efeitos aleatórios, ou em fases intermediárias e finais, quando são preferencialmente tidas como de efeitos fixos. Logo, uma curiosidade inicial foi investigar, nos delineamentos em blocos, a influência destas suposições sobre as estimativas das médias genotípicas, bem como sobre o seu ordenamento para fins de seleção (Capítulo 2). O fato também abre a possibilidade de diferentes modelagens para a análise estatística dos dados desses experimentos, incluindo-se o modelo fixo e modelos mistos (análise intrablocos, análise com recuperação de informação interblocos e análises recuperando informação intergenotípica). A apresentação destas alternativas e suas implicações na seleção de genótipos constitui o objetivo principal do Capítulo 3. Acrescenta-se que, na abordagem de modelos mistos, uma etapa fundamental é a de estimação dos componentes de variância. Isto é passível de realização por meio de vários métodos estatísticos, cujos resultados, todavia, podem ser bastante conflitantes; sobretudo em caso de desbalanceamento. Dada a escassez de informações específicas e o fato de esses delineamentos serem naturalmente desbalanceados, avaliaram-se através de simulação em computador as propriedades dos principais estimadores disponíveis: ANOVA, MIVQUE(0), ML e REML (Capítulo 4). Outra característica marcante desses ensaios, particularmente nas etapas iniciais, é a adoção de parcelas de pequeno tamanho, haja vista a pouca disponibilidade de material de propagação. Isto, associado à costumeira alocação sistemática de testemunhas e/ou grupos de linhagens aparentadas, suscitou a avaliação de um procedimento de análise estatística que não ficasse sujeito à clássica suposição de independência espacial entre observações (Capítulo 5). Entre os resultados e conclusões obtidas pode-se destacar: i) a análise intrablocos (modelo fixo) pode fornecer ordenamentos inadequados das médias dos genótipos se estes forem de efeitos aleatórios e, sobretudo, se estiverem relacionados a diferentes populações de referência (Capítulo 2); ii) a classificação das novas linhagens em relação aos cultivares testemunhas pode mudar sensivelmente de um modelo de análise para outro, principalmente quando se passa da análise intrablocos para uma análise que recupera informação interlinhagens (Capítulo 3); iii) o método MIVQUE(0) comparativamente fornece estimativas de melhor qualidade para os componentes de variância, em particular se os genótipos vierem de população(ões) com baixa(s) variância(s) genotípica(s) e os experimentos forem relativamente pequenos (Capítulo 4); e, iv) em experimentos com observações correlacionadas espacialmente, a discriminação genotípica e o ordenamento dos genótipos para fins de seleção podem ser melhorados consideravelmente através da análise estatística espacial (Capítulo 5). This research investigates experimental and statistical problems related with the use of the augmented block design in plant breeding programs. A characteristic of these designs is that treatments are of two categories, namely: common checks (generally commercial varieties replicated over blocks) and the additional or new treatments (usually not replicated), the latter being the ones under evaluating for selection purposes. The relation of this design with block designs in general and fundaments required for its applications and analysis, as well as information about other topics (mixed models, components of variance and spatial analysis) were reviewed in the Chapter 1. For analysis and discussion a group of 41 trials, set up at the Department of Genetics (ESALQ, USP) for evaluating soybean inbred lines, was used. Only trials having a complete layout of the spatial position of plots in the field were taken. Analyses and discussions given here refer only to grain yield (kg/ha). It is known that these trials are usually conducted at preliminary stages, when genotypes can be statistically assumed as having random effects, or at intermediate and final stages when they are preferentially considered with fixed effects. The first interesting point here investigated was the influence of these assumptions on the estimates of genotypic means, as well as on the ranking of lines for selection purposes (Chapter 2). The assumptions open the possibility of considering either fixed or mixed models for analysis (intrablock analysis, or others with recovering of interblock or intergenotypic information). Chapter 3 shows the corresponding analytical procedures and their consequences on the ranking and selection of genotypes. Under mixed models a fundamental step is the estimation of variance components, for which several procedures are available. It is known that these procedures may lead to different estimates of the same parameter, specially when experiments are unbalanced. Due to the lack of specific information about its point, and since these designs are naturally unbalanced, computer simulations were made here for evaluating the properties of the different available estimators, specifically: ANOVA, MIVQUE(0), ML and REML (Chapter 4). An additional characteristic of these design, at initial stages of breeding programs, is the use of small-sized plots, necessary to accommodate the lack of seeds. This fact in addition to the common practice of systematic arrangement of check plots in the field and/or the arrangement of genetically related treatments in sets, motivated the application of spatial statistics procedures (Chapter 5). The following main results and conclusions can be pointed out: i) the intrablock analysis (fixed model) can provide inadequate ranking of the genotypic means if genotypes have random effects and, specially if they are stem from different populations (Chapter 2); ii) the classification of the new genetic treatments in relation to check varieties may change considerably, depending on the model adopted, specially when the intrablock and the analyses with recovery of intergenotypic information are compared (Chapter 3); iii) the MIVQUE(0) method, in general, furnished more efficient estimates of variance components, particularly if genotypes are derived from population(s) with low genotypic variance(s) and experiments are of small size (Chapter 4); and, iv) if the experimental observations are spatially correlated the discrimination among genotypes and the ranking of genetic treatments can be substantially improved through spatial statistical analysis (Chapter 5).