Expression and validation of PvPGIP genes for resistance to white mold (Sclerotinia sclerotiorum) in common beans (Phaseolus vulgaris L.).

The interaction between polygalacturonase-inhibiting proteins (PGIPs), produced by plants, and endopolygalacturonases (PGs), produced by fungi, limits the destructive potential of PGs and can trigger plant defense responses. This study aimed to i) investigate variation in the expression of different common bean (Phaseolus vulgaris L.) genotypes and its relationship with resistance to white mold (Sclerotinia sclerotiorum); ii) determine the expression levels of PvPGIP genes at different time points after inoculation with white mold; and iii) investigate differences in PvPGIP gene expression between two white mold isolates with different levels of aggressiveness. Four bean lines were analyzed, including two lines from a recurrent selection for white mold (50/5 and 84/6), one resistant line that was not adapted to Brazilian conditions (Cornell 605), and one susceptible line (Corujinha). Gene expression was investigated at 0, 1, 2, 3, and 5 days after inoculation. The isolate UFLA 03 caused no significant difference in the relative expression of any gene examined, and was inefficient in discriminating among the genotypes. For the isolate UFLA 116, all of the genes were differentially expressed, as they were associated with resistance to white mold, and the expressions increased until the third day after inoculation. The 50/5 line was not significantly different from the Corujinha line for all of the genes analyzed. However, this line had a resistance level that was similar to that of Cornell 605, according to the straw test. Therefore, the incorporation of PvPGIP genes can increase the resistance of lines derived from recurrent selection.

White mold resistance-associated quantitative trait loci in the Jalo x Small White common bean population.

We aimed to identify simple sequence repeat (SSR) markers linked to quantitative trait loci (QTLs) associated with white mold resistance in a segregating population derived from a cross between common bean cultivars Jalo and Small White, in the Southern State of Minas Gerais. Parents were crossed to obtain the F2 generation of 190 plants. From these, F2:3 and F2:4 progenies were obtained for phenotypic evaluation. DNA was extracted from F2 plants and parents for genotyping with SSR primers. For phenotypic assessment by the straw test, we used 190 F2:3 progenies and six lines in a triple-lattice design of 14 x 14 m. Nine trials were conducted for phenotyping by the oxalic acid method to evaluate 177 F2:4 progenies, in addition to the two parents and two common treatments represented by the Jalo and Corujinha lines. The experimental design for the oxalic acid method was completely randomized with three replicates. Adjusted means of evaluations related to F2:3 and F2:4 were used to identify QTLs by using the moving away method from the marker under Bayesian analysis. The markers GATS91, BM197, and X60000 stood out with high heritability and with effects on disease reduction by the straw test; therefore, these markers are promising for selection. The markers BM183, BM189, and SSR-IAC143 were associated with the QTLs identified by oxalic acid, providing greater effects in white mold resistance with high heritability. Based on the oxalic acid and straw test methods, the most prominent marker was PVBR189.

Analysis of genetic diversity of Laeliinae (Orchidaceae) in the State of Sergipe using ISSR markers.

The Orchidaceae represent one of the largest and most diverse families on the planet. However, this family is constantly threatened by predators and by the advancement of urban centers over its natural habitats. The objective of this study was to use inter-simple sequence repeat markers to evaluate the genetic diversity between orchid accessions of the Laeliinae subtribe, which comprise part of the Orchidaceae study collection at the Department of Agronomic Engineering of the Federal University of Sergipe. DNA was extracted from each specimen by using an adapted 2% cetyltrimethyl ammonium bromide protocol. Similarity between individuals was calculated using the Jaccard method. Clustering was carried out by the unweighted pair group method with arithmetic mean method, with resampling and 10,000 bootstraps. Eighty-seven fragments were obtained, all of which were polymorphic, revealing high variability between accessions. The mean similarity was 35.77% between Encyclia sp individuals, and 35.90% between specimens of Cattleya tigrina. For Epidendrum secundum, a relationship between geographic and genetic distances was observed, and the accession collected in the southern part of the State of Sergipe (Serra de Itabaiana National Park) was more divergent than that of the other parts of the state. The data generated in this study will guide further research aimed at the ex situ conservation of these materials.

Short Communication Quick method for identifying horse (Equus caballus) and donkey (Equus asinus) hybrids.

The domestication of the Equus genus 5000-6000 years ago has influenced the history of human civilization. As soon as horse and donkey species had been domesticated, they were crossbred, producing humanity's first documented attempt at animal genome manipulation. Since then, the mule (male donkey x female horse) and the reciprocal cross (the hinny, male horse x female donkey) have been the most common equine hybrids in the world. Due to their hybrid vigor, mules and hinnies have been intensively used for carrying loads and people and for tilling the land. Despite their importance, visual distinction of mules and hinnies is difficult due to high phenotypic resemblance. However, the distinction between these two hybrids is of pivotal importance for equid breeders and ranchers. In this study, an easy, low-cost, effective, and fast multiplex-polymerase chain reaction method was developed to distinguish the maternal origin of mules and hinnies, targeting the hyper-variable mitochondrial DNA D-loop region. This methodology can help breeders, ranchers, animal science professionals, and researchers manage their equine herds with more confidence and precision.

A new method of QTL identification for undersaturated maps.

In many species, low levels of polymorphism prevent the assembly of linkage maps that are used to identify genetic markers related to the expression of quantitative trait loci (QTLs). This study compared two methods of locating QTLs in association studies that do not require a previous estimation of linkage maps. Method I (MI) was a Bayesian multiple marker regression and Method II (MII) combined multiple QTL mapping and "moving away from markers". In this method, markers are not directly regressed to the phenotype, but are used as pivots to search for QTLs along the genome. To compare methods, we simulated 300 individuals from an F2 progeny with two levels of marker loss (20 and 80%). A total of 165 markers and seven QTLs were spread along 11 chromosomes (roughly emulating the genetic structure of the common bean, Phaseolus vulgaris). A real data example with 186 progenies of a F2:4 generation of the species was analyzed using 59 markers (17 simple sequence repeats, 31 amplified fragment length polymorphisms, and 11 sequence-related amplified polymorphisms). MII was more precise than MI for both levels of marker loss. For real data, MII detected 17 candidate positions for QTLs, whereas MI did not detect any. MII is a powerful method that requires further studies with actual data and other designs such as crossover, and genome-wide studies.

Genetic divergence of common bean cultivars.

The aim of this study was to evaluate genetic divergence in the 'Carioca' (beige with brown stripes) common bean cultivar used by different institutions and in 16 other common bean cultivars used in the Rede Cooperativa de Pesquisa de Feijão (Cooperative Network of Common Bean Research), by using simple sequence repeats associated with agronomic traits that are highly distributed in the common bean genome. We evaluated 22 polymorphic loci using bulks containing DNA from 30 plants. There was genetic divergence among the Carioca cultivar provided by the institutions. Nevertheless, there was lower divergence among them than among the other cultivars. The cultivar used by Instituto Agronômico do Paraná was the most divergent in relation to the Carioca samples. The least divergence was observed among the samples used by Universidade Federal de Lavras and by Embrapa Arroz e Feijão. Of all the cultivars, 'CNFP 10104' and 'BRSMG Realce' showed the greatest dissimilarity. The cultivars were separated in two groups of greatest similarity using the Structure software. Genetic variation among cultivars was greater than the variation within or between the groups formed. This fact, together with the high estimate of heterozygosity observed and the genetic divergence of the samples of the Carioca cultivar in relation to the original provided by Instituto Agronômico de Campinas, indicates a mixture of cultivars. The high divergence among cultivars provides potential for the utilization of this genetic variability in plant breeding.

Identification of QTLs of resistance to white mold in common bean from multiple markers by using Bayesian analysis.

In this study, we identified simple sequence repeat, ampli-fied fragment length polymorphism, and sequence-related amplified poly-morphism markers linked to quantitative trait loci (QTLs) for resistance to white mold disease in common bean progenies derived from a cross between lines CNFC 9506 and RP-2, evaluated using the oxalic acid test and using Bayesian analysis. DNA was extracted from 186 F2 plants and their parental lines for molecular analysis. Fifteen experiments were car-ried out for phenotypic analysis, which included 186 F2:4 progenies, the F1 generation, the F2 generation, and the lines CNFC 9506, RP-2, and G122 as common treatments. A completely randomized experimental design with 3 replications was used in controlled environments. The adjusted means for the F2:4 generation were to identify QTLs by Bayesian shrink-age analysis. Significant differences were observed among the progenies for the reaction to white mold. The moving away method under the Bayes-ian approach was effective for identifying QTLs when it was not possible to obtain a genetic map because of low marker density. Using the Wald test, 25 markers identified QTLs for resistance to white mold, as well as 16 simple sequence repeats, 7 amplified fragment length polymorphisms, and 2 sequence-related amplified polymorphisms. The markers BM184, BM211, and PV-gaat001 showed low distances from QTLs related white mold resistance. In addition, these markers showed, signal effects with increasing resistance to white mold and high heritability in the analysis with oxalic acid, and thus, are promising for marker-assisted selection.

Color flow Doppler sonography for the etiologic diagnosis of thyrotoxicosis.

The objective of this prospective study was to compare the results of color flow Doppler sonography (CFDS) and radioiodine scintigraphy in patients with thyrotoxicosis. A total of 176 patients, 102 with clinical thyrotoxicosis and 74 with subclinical dysfunction, were included. Pregnant and breast-feeding women, patients using amiodarone or recently exposed to iodinated contrast, and patients treated with antithyroid drugs were excluded. Total T3, free T4, TSH, and anti-TSH receptor antibodies were measured before scintigraphy and CFDS. Excluding one patient whose etiology of thyrotoxicosis remained undefined, CFDS showed 100% specificity. In fact, in all 10 cases in which scintigraphy and CFDS provided discordant results, the diagnosis suggested by the latter was correct. In patients with clinical thyrotoxicosis, the sensitivity of CFDS was 96% for diffuse toxic goiter, 95% for the absence of hyperfunction, and 100% for toxic nodular disease. In patients with subclinical dysfunction, the sensitivity of CFDS was 72.7% for diffuse toxic goiter, 90% for toxic adenoma, and 86.6% for toxic multinodular disease. CFDS was inconclusive in patients with parenchymal blood flow with patchy uneven distribution or with macronodules in which nodule vascularity compared to the remaining parenchyma did not permit to establish the diagnosis with certainty. CFDS can be used instead of scintigraphy not only in situations in which the latter is contraindicated or of limited value to define the etiology of thyrotoxicosis.

Reaction of common bean lines and aggressiveness of Sclerotinia sclerotiorum isolates.

The aims of this study were to evaluate the reaction of common bean lines to white mold, the aggressiveness of different Sclerotinia sclerotiorum isolates from various common bean production areas in Brazil, and comparison of the diallel and GGE (genotype main effect plus genotype-by-environment interaction) biplot analysis procedures via study of the line-by-isolate interaction. Eleven common bean (Phaseolus vulgaris) lines derived from 3 backcross populations were used. Field experiments were performed in the experimental area of the Departamento de Biologia of the Universidade Federal de Lavras, Lavras, MG, Brazil, in the 2011 and 2012 dry crop season and 2011 winter crop season through a randomized block design with 3 replications. This study was also set up in a greenhouse. Inoculations were performed 28 days after sowing by means of the straw test method. The reaction of the bean lines to white mold was assessed according to a diagrammatic scale from 1 (plant without symptoms) to 9 (dead plant). Estimations of general reaction capacity (lines) and general aggressiveness capacity (isolates) indicated different horizontal levels of resistance in the lines and levels of aggressiveness in the isolates. Therefore, it was possible to select more resistant lines and foresee those crosses that are the most promising for increasing the level of resistance. It was also possible to identify the most aggressive isolates that were more efficient in distinguishing the lines. Both diallel and GGE biplot analyses were useful in identifying the genotypic values of lines and isolates.

Follow-up of patients with low-risk papillary thyroid carcinoma and undetectable basal serum thyroglobulin after ablation measured with a sensitive assay: a prospective study.

The importance of thyroglobulin (Tg) stimulation after ablation in patients with papillary thyroid carcinoma (PTC) and undetectable basal Tg measured with sensitive assays has been questioned. However, there is a need for prospective studies that evaluate the evolution of these patients when stimulated Tg is omitted and this was the objective of the present investigation. One hundred twenty-two consecutive patients with PTC with the following characteristics were evaluated: submitted to total thyroidectomy and remnant ablation; low risk for recurrence; undetectable basal Tg (functional sensitivity of 0.1 ng/ml) 6 months after initial therapy; anti-Tg antibodies (TgAb) negative, and neck ultrasound (US) showing no abnormalities. These patients were not submitted to Tg stimulation. After follow-up for 24-78 months, only one patient (0.8%) presented apparent disease (lymph node metastases). TgAb were detected at low titers and without progression in 1 patient (0.8%). Tg became detectable and continued to be detectable in 3 patients (2.4%), but at concentrations ≤0.3 ng/ml in the absence of further increases, with stimulated Tg < 1.4 ng/ml. A total of 117 patients (96%) coursed with no apparent disease throughout follow-up and had undetectable Tg at the end of the study. Of these, 111 showed undetectable Tg in all measurements and 6 showed detectable Tg in some of them, although Tg later returned spontaneously to an undetectable range. After ablation, the risk of recurrence is very low in patients with low-risk PTC who show undetectable basal Tg measured with a sensitive assay, negative TgAb and negative US.

Peripheral nerve regeneration in rats using nerve graft in a vein conduit pre-filled with platelet-rich fibrin (PRF).

Treatment of peripheral nerve injury is not always satisfactory. To improve results, specific adjuvant methods have been used, such as platelet-rich fibrin (PRF) and vein conduits. The goal of this study was to assess whether use of PRF and vein conduits after nerve suture improves nerve regeneration as measured by a functional score and histomorphometry analysis. Ten isogenic spontaneously hypertensive rats were randomly assigned to 4 experimental procedures: 1) Sham group (n = 10); 2) Nerve graft (NG) group (n = 10); 3) Nerve graft covered with a vein conduit (NGVC) (n = 10); and 4) Nerve graft covered with a vein conduit pre-filled with PRF (NGVCP) (n = 10). Nerve repair results were evaluated on: sciatic functional index (SFI) at 0, 30, 60 and 90 days; morphometric and morphologic analysis of the distal nerve; and histological analysis of Fluoro-Gold® stained motor neurons in the anterior horn of the spinal cord. Compared to the Sham control group, the NGVC and NGVCP groups exhibited lower SFI on all measures. The NGVC group showed improvement in SFI at day 90, which was significant compared to the NG group. Fiber and axon diameters were comparable in the NGVC and NGVCP groups, which were both significantly lower than in the Sham and NG groups. Significant improvement was expected with PRF, but in fact the release of factors from this substance was not as effective as hoped.

Lactate modulates cardiac gene expression in mice during acute physical exercise.

The aim of the present study was to verify the role of lactate as a signaling molecule in cardiac tissue under physiological conditions. C57BL6/J male mice were submitted to acute running bouts on a treadmill at different exercise intensities (30, 60, and 90% of maximal speed - Smax) under the effect of two doses (0.5 and 5 mM) of α-cyano-4-hydroxycynnamate (CINN), a blocker of lactate transporters. Cardiac lactate levels, activity of the enzymes of glycolytic [hexokinase (HK) and lactate dehydrogenase (LDH)] and oxidative metabolism [citrate synthase (CS)], and expression of genes also related to metabolism [LDH, nuclear factor erythroid 2-related factor 2 (NRF-2), cytochrome oxidase IV (COX-IV), and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α)] were evaluated. Elevated cardiac lactate levels were observed after high intensity running at 90% of Smax, which were parallel to increased activity of the HK and CS enzymes and mRNA levels of PGC-1α and COX-IV. No changes were observed in cardiac lactate levels in mice running at lower exercise intensities. Interestingly, prior intraperitoneal administration (15 min) of CINN (0.5 mM) significantly reduced cardiac lactate concentration, activities of HK and CS, and mRNA levels of PGC-1α and COX-IV in mice that ran at 90% of Smax. In addition, cardiac lactate levels were significantly correlated to both PGC-1α and COX-IV cardiac gene expression. The present study provides evidence that cardiac lactate levels are associated to gene transcription during an acute bout of high intensity running exercise.

Outcome of carpal tunnel release surgery in patients with and without Linburg-Comstock anomaly.

Anatomical variations may entail increased volume within the carpal tunnel and consequently the development of carpal tunnel syndrome (CTS) symptoms. The clinical importance of anomalous connection between the flexor pollicis longus (FPL) and flexor digitorum profundus (FDP) tendons was described by Linburg and Comstock. The objective of the present study was to compare postoperative outcomes of carpal tunnel release surgery in patients with and without Linburg-Comstock anomaly (LCA). Hands of CTS patients with and without LCA were evaluated for finger sensitivity, grip, tip, key and tripod pinch strength, pain intensity and Boston Carpal Tunnel Questionnaire score. Patients were evaluated preoperatively and 1, 3 and 6 months after surgery. Forty-six hands in 36 CTS patients with LCA and 50 hands in 38 patients without LCA were included. On all study parameters, no significant difference was found between CTS patients with versus without LCA. As outcomes are similar in both cases, LCA resection is not useful in patients with LCA and CTS. Preoperative diagnosis is unnecessary and screening for LCA is non-contributive for CTS evaluation.

Linburg-Comstock anomaly: A comparison of the prevalence in women with and without clinical carpal tunnel syndrome.

We aimed to compare the prevalence of the Linburg-Comstock anomaly in women with and without a clinical diagnosis of carpal tunnel syndrome. The prevalence of the Linburg-Comstock anomaly was evaluated in 400 hands from 200 women over 40 years of age who were diagnosed clinically with carpal tunnel syndrome (CTS), designated as the CTS group. The volunteer group consisted of 400 hands from 200 healthy women over 40 years of age. The women from both groups were asked to carry out the clinical flexion and pain tests described by Linburg and Comstock (1979) as a basis for the clinical diagnosis. CTS patient ages ranged from 40 to 90 (mean 55.8) years, while volunteer group ages ranged from 40 to 93 (mean 55) years. The flexion test was positive in 305 (76%) hands in the CTS group and 242 (60%) hands in the volunteer group. The pain test was positive in 261 (65%) hands in the CTS group and 108 (27%) hands in the volunteer group. Both tests were positive in 244 (61%) hands in the CTS group and 98 (24%) hands in the volunteer group. All these differences were statistically significant. Based on clinical examination using the flexion and pain tests, the prevalence of Linburg-Comstock anomaly was statistically higher in the group of women with carpal tunnel syndrome than in healthy volunteers.

Ecotoxicological effects of commercial herbicides on the reproductive system of aquatic arthropod Limnocoris submontandoni (Hemiptera: Naucoridae).

Worldwide, conventional agriculture makes extensive use of pesticides. Although the effects of herbicides are relatively well known in terms of environmental impacts on non-target organisms, there is very little scientific evidence regarding the impacts of herbicide residues on aquatic arthropods from tropical conservation areas. This study evaluates for the first time the toxicity of the herbicides ametryn, atrazine, and clomazone on the aquatic insect Limnocoris submontandoni (Hemiptera: Naucoridae). The lethal concentration (LC50) of herbicides was evaluated for these insects, as well as the effect of the herbicides on the insects' tissues and testicles. The estimated LC50 was 1012.41, 192.42, and 46.09 mg/L for clomazone, atrazine, and ametryn, respectively. Spermatocyte and spermatid changes were observed under the effect of atrazine, and effects on spermatogenesis were observed for some concentrations of clomazone, with apparent recovery after a short time. Our results provide useful information on the effects of herbicide residues in aquatic systems. This information can help minimize the risk of long-term reproductive effects in non-target species that have been previously overlooked in ecotoxicology studies.

Does an ulnar styloid fracture interfere with the results of a distal radius fracture?

BACKGROUND: The ulnar styloid is a supportive structure for the capsular ligament complex of the distal radioulnar joint. The relation between fractures of the ulna and distal radius is not clear, especially in regard to whether ulnar fractures predict worse outcomes for distal radius fractures. The objective of this study was to analyze the influence of ulnar styloid fractures in patients with reducible and unstable distal radius fractures. METHODS: A total of 100 patients with unstable and reducible distal radius fractures, with or without an ulnar styloid fracture, were randomly assigned to treatment with transarticular bridging external fixation or transulnar percutaneous pinning. Follow-up was obtained for 91 patients. For the secondary data analysis, three patient cohorts were created: a no ulnar styloid fracture group with the radius fracture treated by pinning or external fixation (n = 30); an ulnar styloid fracture with radius fracture group treated by external fixation (n = 31); and an ulnar styloid fracture with radius fracture treated by pinning (n = 30). Functional and radiological outcomes were measured at 6 and 24 months. Functional outcome measures included wrist pain (visual analogue scale) and the Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire. RESULTS: At 24 months, patients with both fractures had worse wrist pain and worse scores on the DASH questionnaire than the patients with an isolated distal radius fracture; and those treated by pinning had less wrist pain and showed better scores on the DASH questionnaire than the patients treated by fixation. CONCLUSIONS: Ulnar styloid fracture may be a predictive factor of worse functional outcome for distal radius fracture. Pinning and above-the-elbow casting, used to treat ulnar styloid fractures, led to better function than fixation.

Ecotoxicological effects of commercial herbicides on the reproductive system of aquatic arthropod Limnocoris submontandoni (Hemiptera: Naucoridae)

Abstract Worldwide, conventional agriculture makes extensive use of pesticides. Although the effects of herbicides are relatively well known in terms of environmental impacts on non-target organisms, there is very little scientific evidence regarding the impacts of herbicide residues on aquatic arthropods from tropical conservation areas. This study evaluates for the first time the toxicity of the herbicides ametryn, atrazine, and clomazone on the aquatic insect Limnocoris submontandoni (Hemiptera: Naucoridae). The lethal concentration (LC50) of herbicides was evaluated for these insects, as well as the effect of the herbicides on the insects tissues and testicles. The estimated LC50 was 1012.41, 192.42, and 46.09 mg/L for clomazone, atrazine, and ametryn, respectively. Spermatocyte and spermatid changes were observed under the effect of atrazine, and effects on spermatogenesis were observed for some concentrations of clomazone, with apparent recovery after a short time. Our results provide useful information on the effects of herbicide residues in aquatic systems. This information can help minimize the risk of long-term reproductive effects in non-target species that have been previously overlooked in ecotoxicology studies.

Resumo Em todo o mundo, a agricultura convencional faz uso extensivo de pesticidas. Embora os efeitos dos herbicidas sejam relativamente bem conhecidos em termos de impactos ambientais em organismos não-alvo, há pouca evidência científica sobre os impactos de resíduos de herbicidas em artrópodes aquáticos de áreas de conservação tropicais. Este estudo avalia pela primeira vez a toxicidade dos herbicidas ametryn, atrazine e clomazone sobre o inseto aquático Limnocoris submontandoni (Hemiptera: Naucoridae). A concentração letal (LC50) de herbicidas foi avaliada para esses insetos, bem como o efeito dos herbicidas nos tecidos e testículos dos insetos. A LC50 estimada foi de 1012,41, 192,42 e 46,09 mg/L para clomazone, atrazine e ametryn, respectivamente. Alterações nos espermatócitos e espermátides foram observadas sob o efeito de atrazine, e efeitos na espermatogênese foram observados para algumas concentrações de clomazone, com aparente recuperação após um curto período de tempo. Nossos resultados fornecem informações úteis sobre os efeitos de resíduos de herbicidas em sistemas aquáticos. Essas informações podem ajudar a minimizar o risco de efeitos reprodutivos de longo prazo em espécies não-alvo que foram negligenciadas anteriormente em estudos de ecotoxicologia.

Ecotoxicological effects of commercial herbicides on the reproductive system of aquatic arthropod Limnocoris submontandoni (Hemiptera: Naucoridae) / Efeitos ecotoxicológicos de herbicidas comerciais no sistema reprodutivo do artrópode aquático Limnocoris submontandoni (Hemiptera: Naucoridae)

Abstract Worldwide, conventional agriculture makes extensive use of pesticides. Although the effects of herbicides are relatively well known in terms of environmental impacts on non-target organisms, there is very little scientific evidence regarding the impacts of herbicide residues on aquatic arthropods from tropical conservation areas. This study evaluates for the first time the toxicity of the herbicides ametryn, atrazine, and clomazone on the aquatic insect Limnocoris submontandoni (Hemiptera: Naucoridae). The lethal concentration (LC50) of herbicides was evaluated for these insects, as well as the effect of the herbicides on the insects' tissues and testicles. The estimated LC50 was 1012.41, 192.42, and 46.09 mg/L for clomazone, atrazine, and ametryn, respectively. Spermatocyte and spermatid changes were observed under the effect of atrazine, and effects on spermatogenesis were observed for some concentrations of clomazone, with apparent recovery after a short time. Our results provide useful information on the effects of herbicide residues in aquatic systems. This information can help minimize the risk of long-term reproductive effects in non-target species that have been previously overlooked in ecotoxicology studies.

Resumo Em todo o mundo, a agricultura convencional faz uso extensivo de pesticidas. Embora os efeitos dos herbicidas sejam relativamente bem conhecidos em termos de impactos ambientais em organismos não-alvo, há pouca evidência científica sobre os impactos de resíduos de herbicidas em artrópodes aquáticos de áreas de conservação tropicais. Este estudo avalia pela primeira vez a toxicidade dos herbicidas ametryn, atrazine e clomazone sobre o inseto aquático Limnocoris submontandoni (Hemiptera: Naucoridae). A concentração letal (LC50) de herbicidas foi avaliada para esses insetos, bem como o efeito dos herbicidas nos tecidos e testículos dos insetos. A LC50 estimada foi de 1012,41, 192,42 e 46,09 mg/L para clomazone, atrazine e ametryn, respectivamente. Alterações nos espermatócitos e espermátides foram observadas sob o efeito de atrazine, e efeitos na espermatogênese foram observados para algumas concentrações de clomazone, com aparente recuperação após um curto período de tempo. Nossos resultados fornecem informações úteis sobre os efeitos de resíduos de herbicidas em sistemas aquáticos. Essas informações podem ajudar a minimizar o risco de efeitos reprodutivos de longo prazo em espécies não-alvo que foram negligenciadas anteriormente em estudos de ecotoxicologia.

Genetic control of the resistance of common beans to white mold using the reaction to oxalic acid.

The use of genetically resistant cultivars is the best method to reduce losses caused by white mold (Sclerotinia sclerotiorum (Lib.) de Bary). As the best known resistance sources are not adapted, the genetic control of white mold in the common bean must be understood to guide breeding more efficiently. The objective of the present study was to identify the genetic control of the resistance of common bean to white mold by an indirect method using oxalic acid. For this, the descendents of the VC3 cross (susceptible) x G122 (resistant) were used. The trait was assessed by a descriptive key of scores after treatment with oxalic acid. The assessments were made on individual plants (P1, P2, F1, F2 populations and within F2:3 families) in a complete randomized design and on family means where the randomized block design was used with two replications. The oxalic acid method was efficient in detecting genetic differences. The additive effects dominated and genetic control was characterized by partial dominance (d/a = 0.47). At least one resistance gene is involved, although the trait is greatly influenced by the environment. The broad sense heritability at the family mean level (0.47) was greater than that obtained at the individual plant level (0.33), indicating that selection should be more efficient based on progeny mean assessments.