Molecular characterization and demographic insights into soybean bud borer (Lepidoptera: Tortricidae) in Brazil.

The soybean bud borer, a soybean pest in Brazil, was initially identified as Crocidosema aporema (Walsingham 1914) (Lepidoptera: Tortricidae). Outbreaks of this species have recently increased, but identification of this pest remains uncertain, and the historical factors associated with its geographic distribution in Brazil are little known. Here, we conducted a species characterization and phylogeographic analysis based on molecular and morphological evidence. Ninety individuals of bud-borers Lepidoptera were collected in different regions of Brazil. We sequenced COI and COII mitochondrial genes and examined wing patterns and male genital morphology. DNA barcoding approach revealed that 10 individuals were Argyrotaenia sphaleropa (Meyrick 1909) (Lepidoptera: Tortricidae) and 80 were a species of the genus Crocidosema Zeller. The morphology of the adult genitalia and wings proved to be insufficient to confirm the identification of Brazilian individuals as C. aporema, a species originally described from a high-elevation site in Costa Rica. Furthermore, the genetic distance between putative C. aporema specimens from Brazil and Costa Rica (ranging from 5.2% to 6.4%) supports the hypothesis that the Brazilian specimens are not referable to C. aporema. Our analysis revealed a single genetic strain (i.e., species) with low genetic diversity on soybean crops. We found no indication that the genetic structure was related to geographic distance among populations or edaphoclimatic regions. The population expansion of the soybean bud borer coincides with the increase in the area of soybean production in Brazil, suggesting that expanded soybean farming has allowed a significant increase in the effective population size of this pest.

Molecular orbital and topological electron density study of n → π* interactions: amides and thioamides cases.

The n → π* interactions were studied in amides and thioamides systems models, through the analysis of the electron density topology along with the Natural Bonding Orbital (NBO) approach. The effect of the dispersion terms was assessed using different DFT functionals. The NBO, independent gradient model (IGM), and the analysis of the reduced density gradient outcomes show that dispersion forces play a significant role in the strength of n → π* interactions. The IGM results indicate that δg height values for n → π* interactions do not extend beyond 0.025. All the methods used in this work predict that n → π* interaction between pairs of thioamides is stronger than those between amides. However, the electron density topology-based methods were not able to replicate the trends in the relative force of this interaction found in the experimental and NBO results.

Corrigendum: The impact of the parental support on risk factors in the process of gender affirmation of transgender and gender diverse people.

[This corrects the article DOI: 10.3389/fpsyg.2018.00399.].

Characterizing the lethal and sub-lethal effects of genetically modified soybean expressing Cry1A.105, Cry2Ab2, and Cry1Ac insecticidal proteins against Spodoptera species (Lepidoptera: Noctuidae) in Brazil.

BACKGROUND: MON 87701 × MON 89788 × MON 87751 × MON 87708 soybean, that expresses Cry1A.105, Cry2Ab2, and Cry1Ac insecticidal proteins and confers tolerance to glyphosate and dicamba, is a potential tool for managing Spodoptera species in soybean fields in Brazil. In this study, we characterized the lethal and sub-lethal effects of Cry1A.105/Cry2Ab2/Cry1Ac soybean against Spodoptera species and genotypes of Spodoptera frugiperda resistant and susceptible to Cry1 and Cry2 proteins. These evaluations were also conducted with MON 87701 × MON 89788 soybean, which expresses Cry1Ac protein. RESULTS: Cry1A.105/Cry2Ab2/Cry1Ac soybean caused high lethality in neonates of Spodoptera cosmioides and Spodoptera albula. However, it showed low lethality in S. frugiperda genotypes homozygous for resistance to Cry1 and Cry2 proteins but reduced their population growth potential. No relevant lethal effects of Cry1Ac soybean were detected in the Spodoptera species and genotypes evaluated. Spodoptera frugiperda genotypes heterozygous for Cry1 and Cry2 resistance were controlled by Cry1A.105/Cry2Ab2/Cry1Ac soybean, with no insects developing into adults. This Bt soybean also caused intermediate mortality of neonates of Spodoptera eridania (60%-83%) but no surviving larvae developed to adulthood, resulting in population suppression. CONCLUSIONS: Cry1A.105/Cry2Ab2/Cry1Ac soybean caused high mortality of S. cosmioides, S. albula, and S. frugiperda genotypes susceptible to Cry1 and Cry2 and heterozygous for Cry1 and Cry2 resistance. This Bt soybean also suppressed population growth of S. eridania but had minimal impact on S. frugiperda homozygous for resistance to Cry1 and Cry2 proteins. Cry1Ac soybean had minimal impact on all Spodoptera species and genotypes evaluated. © 2022 Society of Chemical Industry.

Key points for translating wound regenerative agents from in vivo assays in mice to clinical validation.

Skin wound healing leads to the recovery of tissue structure and homeostasis after injury. Numerous factors can hamper wound healing and complete recovery of the harmed tissue, causing the formation of scars or chronic wounds. Therapeutic options to improve wound regeneration are limited, possibly due to failure during pre-clinical validation toward clinical trials. In this article, the authors aim to convey key points and provide recommendations for the development of regenerative agents that improve wound healing using mouse models.First, the authors highlight the differences in the wound healing processes of mice and humans. Later, the authors apply a quasi-systematic research approach based on a search algorithm of 32 terms that focuses on in vivomouse model assays of regenerative factors. The authors analyze the top 20 most cited articles of 2241 hits produced by Scopus. The authors focus the search on a period covering the last 10 years (January 2011 to October 2021). The authors synthesize information from the top 20 articles and present the most common type of mouse model used, mouse characteristics (strain, sex, age, weight), surgical wounding technique employed (size, location, equipment), agents tested, methods of wound monitoring, regeneration assessment and key points to consider for the translational potential of these agents. This knowledge will help the scientific community design better in vivo assays and translate their results to further research and clinical validation.

Vigilancia de virus sincicial respiratorio e influenza en niños escolarizados asistidos en un hospital pediátrico durante 2 meses del segundo semestre de 2021 / Respiratory syncytial virus and influenza surveillance in schoolchildren seen at a children's hospital over 2 months of the second semester of 2021

Introducción. Durante la pandemia de COVID-19, disminuyeron las notificaciones de infecciones respiratorias. El objetivo fue estimar la prevalencia de virus sincicial respiratorio (VSR) e influenza en niños escolarizados asistidos en un hospital pediátrico durante el retorno a la presencialidad. Métodos. Estudio transversal de casos sospechosos de COVID-19, de 3-18 años, con prueba negativa para SARSCoV-2, entre agosto y octubre de 2021. Se estratificó por nivel educativo. Se utilizó PCR para detectar VSR e influenza. Resultados. Se incluyeron 619 niños: 234 del nivel inicial, 224 del primario y 161 del secundario; 25,5 % (158) fueron positivos para VSR (36,3 % del nivel inicial versus 21 % del primario y 16 % del secundario); en adolescentes se asoció la infección al contacto escolar con caso sintomático (OR 2,5; IC95%: 1-6,80; p = 0,04). No se aisló virus influenza. Conclusión. VSR se aisló en un cuarto de la población estudiada, con mayor frecuencia en el nivel inicial; en adolescentes, se asoció con contacto escolar sintomático. No se detectaron casos de influenza

Introduction. Reporting of respiratory infections reduced during the COVID-19 pandemic. The objective was to estimate the prevalence of respiratory syncytial virus (RSV) and influenza in schoolchildren seen at a children's hospital during the return to school. Methods. Cross-sectional study of patients aged 3­18 years suspected of COVID-19 with a negative test for SARS-CoV-2 between August and October 2021. Participants were stratified by level of education. PCR was used to detect RSV and influenza. Results. A total of 619 children were included: 234 in preschool, 224 in primary and 161 in secondary school; 25.5% (158) tested positive for RS (36.3% in the pre-school level versus 21% in primary and 16% in secondary school). Infection among adolescents was associated with school contact with symptomatic cases (OR 2.5; 95%CI 1­6.80; p = 0.04). No case of influenza was detected. Conclusion. RSV was isolated in one fourth of the study population, with a higher frequency in pre-school; among adolescents, it was associated with school contact with symptomatic cases. No case of influenza was detected.

Encefalitis inmunomediada en un niño con antecedente de infección por SARS-CoV-2 n / Immune-mediated encephalitis in a child with a history of SARS-CoV-2 infectio

Las encefalitis son cuadros clínicos frecuentes en la edad pediátrica. Pueden dividirse en aquellas causadas por la infección del sistema nervioso central y en las de etiología inmunomediada (algunas de las cuales pueden ser para- o posinfecciosas). En marzo de 2020 la Organización Mundial de la Salud declaró la pandemia por el coronavirus de tipo 2 del síndrome respiratorio agudo grave (SARS-CoV-2, por su sigla en inglés). Los reportes pediátricos de enfermedad por dicho agente describen una amplia gama de manifestaciones clínicas: compromiso respiratorio, gastrointestinal, síntomas neurológicos, entre otros; y el síndrome inflamatorio multisistémico asociado a COVID-19 (SIM-C). Describimos el caso de un niño de 2 años con diagnóstico de encefalitis por anticuerpos antirreceptor N-metil-d-aspartato (anti-NMDAR), en quien se comprobó, mediante serología, una infección reciente por SARS-CoV-2. La presencia de marcadores serológicos positivos para SARS-CoV-2 en un paciente que presentó encefalitis por anticuerpos anti-NMDAR podría interpretarse como una asociación temporal, estableciéndose la posibilidad de que el virus haya actuado como gatillo de una enfermedad autoinmunitaria.

Encephalitis are frequent clinical pictures in pediatric age. They can be divided into those caused by infection of the central nervous system and those of immune-mediated etiology (some of which may be para- or post-infectious). In March 2020, the WHO declared a SARS-CoV-2 pandemic. Pediatric reports of disease caused by this agent describe a wide range of clinical manifestations: respiratory and gastrointestinal compromise, neurological symptoms, among others; and a multisystemic inflammatory syndrome in children associated with COVID-19 (MIS-C).We describe the case of a 2-year-old boy with a diagnosis of anti-NMDAR antibody encephalitis, in whom a recent SARSCoV-2 infection was serologically proven. The presence of positive serological markers for SARS-CoV-2 in a patient who presented encephalitis due to anti-NMDAR antibodies could be interpreted as a temporal association; establishing the possibility that the virus has acted as a trigger for an autoimmune disease

Respiratory syncytial virus and influenza surveillance in schoolchildren seen at a children's hospital over 2 months of the second semester of 2021. / Vigilancia de virus sincicial respiratorio e influenza en niños escolarizados asistidos en un hospital pediátrico durante 2 meses del segundo semestre de 2021.

INTRODUCTION: Reporting of respiratory infections reduced during the COVID-19 pandemic. The objective was to estimate the prevalence of respiratory syncytial virus(RSV) and influenza in schoolchildren seen at a children's hospital during the return to school. METHODS: Cross-sectional study of patients aged 3-18 years suspected of COVID-19 with a negative test for SARS-CoV-2 between August and October 2021. Participants were stratified by level of education. PCR was used to detect RSV and influenza. RESULTS: A total of 619 children were included: 234 in pre-school, 224 in primary and 161 in secondary school; 25.5% (158) tested positive for RSV (36.3% in the pre-school level versus 21% in primary and 16% in secondary school). Infection among adolescents was associated with school contact with symptomatic cases (OR 2.5; 95%CI 1-6.80; p = 0.04). No case of influenza was detected. CONCLUSIONS: RSV was isolated in one fourth of the study population, with a higher frequency in pre-school; among adolescents, it was associated with school contact with symptomatic cases. No case of influenza was detected.

Introducción. Durante la pandemia de COVID-19, disminuyeron las notificaciones de infecciones respiratorias. El objetivo fue estimar la prevalencia de virus sincicial respiratorio (VSR) e influenza en niños escolarizados asistidos en un hospital pediátrico durante el retorno a la presencialidad. Métodos. Estudio transversal de casos sospechosos de COVID-19, de 3-18 años, con prueba negativa para SARS-CoV-2, entre agosto y octubre de 2021. Se estratificó por nivel educativo. Se utilizó PCR para detectar VSR e influenza. Resultados. Se incluyeron 619 niños: 234 del nivel inicial, 224 del primario y 161 del secundario; 25,5 % (158) fueron positivos para VSR (36,3 % del nivel inicial versus 21 % del primario y 16 % del secundario); en adolescentes se asoció la infección al contacto escolar con caso sintomático (OR 2,5; IC95%: 1-6,80; p = 0,04). No se aisló virus influenza. Conclusión. VSR se aisló en un cuarto de la población estudiada, con mayor frecuencia en el nivel inicial; en adolescentes, se asoció con contacto escolar sintomático. No se detectaron casos de influenza.

[Immune-mediated encephalitis in a child with a history of SARS-CoV-2 infection]. / Encefalitis inmunomediada en un niño con antecedente de infección por SARS-CoV-2.

Encephalitis are frequent clinical pictures in pediatric age. They can be divided into those caused by infection of the central nervous system and those of immune-mediated etiology (some of which may be para- or post-infectious). In March 2020, the WHO declared a SARS-CoV-2 pandemic. Pediatric reports of disease caused by this agent describe a wide range of clinical manifestations: respiratory and gastrointestinal compromise, neurological symptoms, among others; and a multisystemic inflammatory syndrome in children associated with COVID-19 (MIS-C). We describe the case of a 2-year-old boy with a diagnosis of anti-NMDAR antibody encephalitis, in whom a recent SARS-CoV-2 infection was serologically proven. The presence of positive serological markers for SARS-CoV-2 in a patient who presented encephalitis due to anti-NMDAR antibodies could be interpreted as a temporal association; establishing the possibility that the virus has acted as a trigger for an autoimmune disease.

Las encefalitis son cuadros clínicos frecuentes en la edad pediátrica. Pueden dividirse en aquellas causadas por la infección del sistema nervioso central y en las de etiología inmunomediada (algunas de las cuales pueden ser para- o posinfecciosas). En marzo de 2020 la Organización Mundial de la Salud declaró la pandemia por el coronavirus de tipo 2 del síndrome respiratorio agudo grave (SARS-CoV-2, por su sigla en inglés). Los reportes pediátricos de enfermedad por dicho agente describen una amplia gama de manifestaciones clínicas: compromiso respiratorio, gastrointestinal, síntomas neurológicos, entre otros; y el síndrome inflamatorio multisistémico asociado a COVID-19 (SIM-C). Describimos el caso de un niño de 2 años con diagnóstico de encefalitis por anticuerpos antirreceptor N-metil-d-aspartato (anti-NMDAR), en quien se comprobó, mediante serología, una infección reciente por SARS-CoV-2. La presencia de marcadores serológicos positivos para SARS-CoV-2 en un paciente que presentó encefalitis por anticuerpos anti-NMDAR podría interpretarse como una asociación temporal, estableciéndose la posibilidad de que el virus haya actuado como gatillo de una enfermedad autoinmunitaria.

MON 95379 Bt maize as a new tool to manage sugarcane borer (Diatraea saccharalis) in South America.

BACKGROUND: The sugarcane borer (SCB), Diatraea saccharalis (Lepidoptera: Crambidae), is a key pest of maize in Argentina, and genetically modified maize, producing Bacillus thuringiensis (Bt) proteins, has revolutionized the management of this insect in South America. However, field-evolved resistance to some Bt technologies has been observed in SCB in Argentina. Here we assessed a new Bt technology, MON 95379, in the laboratory, greenhouse and field for efficacy against SCB. RESULTS: In a laboratory leaf disc bioassay, both MON 95379 (producing Cry1B.868 and Cry1Da_7) and Cry1B.868_single maize (producing only Cry1B.868) resulted in 100% mortality of SCB. The level of Cry1B.868 in the Cry1B.868_single maize is comparable to that in MON 95379 maize. However, the Cry1Da_7 protein does not have high efficacy against SCB, as evidenced by < 20% mortality on Cry1Da_7_single leaf tissue. Total (100%) mortality of SCB in a Cry1B.868_single tissue dilution bioassay indicated that Cry1B.868_single maize meets the criteria to be classified as a high dose. Similar median lethal concentration (LC50 ) values were observed for MON 89034-R and susceptible SCB strains exposed to Cry1B.868 protein. MON 95379 also controlled SCB strains resistant to MON 89034 (Cry1A.105/Cry2Ab2) and Cry1Ab. Under field conditions in Brazil and Argentina, MON 95379 maize plants were consistently protected from SCB damage. CONCLUSION: MON 95379 maize will bring value to maize growers in South America by effectively managing SCB even in locations where resistance to other Bt-containing maize technologies has been reported. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Filgrastim (r-met-hu G-CSF) enhances the efficiency of spermatogenesis in prepubertal Bos indicus bulls.

This study aimed to test the effects of the drug r-met-hu-G-CSF (filgrastim) on spermatogenic efficiency in prepubertal Brahman bulls. Twelve intact, healthy prepubertal bulls were administered 0, 1 (LD = low dose) or 4 (HD = high dose) µg/Kg r-met-hu-G-CSF (daily for 4 days), and haematological analysis was performed. Bulls were castrated (D0 or D60). BW (body weight) and SC (scrotal circumference) were recorded. Testis weight and volume were taken at castration with samples for testis histology and stereology: germ cell types, spermatids count and DSP (daily sperm production per gram)/g of testicular parenchyma. Testicular weight, volume, BW, SC and gonadosomatic index (GSI) were NS (LD-HD; p > .05). At D0 (age 11 months), the most advanced germ cell types (maGCt) ranged from intermediate spermatogonia to pachytene spermatocytes. After 2 months, control animals had round spermatids as maGCt, LD animals 75% round spermatids and 25% elongated spermatids, and HD animals round spermatids. Spermatids/testis were higher in LD (1.23 ± 0.2 millions) than in controls (0.65 ± 0.1 millions, p < .05). Spermatogenic efficiency (DSP/g) was higher in LD (5.4 ± 0.4 million) than in controls (3.2 ± 0.2 million, p < .01). In conclusion, r-met-hu-G-CSF raises spermatogenic efficiency in prepubertal Brahman bulls.

Cytotoxic and antiproliferative activity of thiazole derivatives of Ochraceolide A.

A series of 15 novel 1,3-thiazole amide derivatives of the pentacyclic triterpene Ochraceolide A (1) was synthesized, characterized, and evaluated in vitro against three human cancer cell lines (MCF-7, MDA-MB-231 and SiHa) and a normal cell line (Vero). Synthetic derivatives were obtained by acylation of the 2-aminothiazole triterpene 2, previously reported. Remarkably, the 5-nitrofuramide derivative (2o) showed better cytotoxic and antiproliferative activity than compound 2 and the other derivatives against the three cancer cell lines with CC50 and IC50 values of 1.6-12.7 µM. Furthermore, butyramide derivative (2c) was approximately 25 times more selective than 2, as well as 3.4 times more selective than Docetaxel, against SiHa cells in the cytotoxic assay, while the phenyl amide derivatives were inactive against the three cancer cell lines.

Dystocia and cesarean section in a free-ranging ocelot (Leopardus pardalis) after traumatic spinal cord injury resulting from dog (Canis familiaris) attack.

Background: Ex situ breeding programs are essential to establish genetic resource banks and produce offspring to strengthen the in situ conservation of endangered species. However, many programs fail to maintain viable ex situ populations due to reproductive problems, including dystocia in pregnant females. Dystocia encompasses different emergency obstetric situations for the lives of dams and fetuses that require urgent intervention. This condition has been studied in domesticated species but published records in wildlife, specifically in felines species, are scarce. Case Description: An adult female ocelot (Leopardus pardalis) was referred to the wildlife hospital of the Universidad San Francisco de Quito after being attacked by dogs (Canis familiaris). Neurological tests revealed traumatic spinal cord injury at a thoracolumbar level. Complementary tests (laboratory exams, radiographs, and ultrasound) revealed a full-term pregnancy, failure in the labor progress, and critical fetal stress. A cesarean section was performed, and the newborns received resuscitation care after assessing their viability using the Apgar score system. The neonate with the lowest Apgar score died within the first hour after birth, while the second one showed an increase in Apgar score after resuscitation care and survived the procedure. Conclusion: We provide new obstetric data that could be relevant to save the lives of dams and newborns in related cases for ocelots and other species of wild felids. Furthermore, this study confirms the adverse effects that domestic dogs have on wildlife species.

Low Incidence of Symptomatic Thrombotic Events in Adult Patients Hospitalized with Coronavirus 19: A Retrospective Cohort Study.

BACKGROUND: Since the beginning of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) pandemic, there have been many reports of increased incidence of venous thromboembolism and arterial events as a complication. OBJECTIVE: To determine the incidence of symptomatic thrombotic events (TEs) in patients hospitalized for SARS-CoV2 disease (coronavirus 19 [Covid-19]). METHODS: A retrospective single-center cohort study with adult patients with a positive reverse transcriptase-polymerase chain reaction (rt-PCR) for SARS-CoV2, included from the date of diagnosis of Covid-19 and followed for 90 days or until death. RESULTS: A total of 1621 patients were included in this study. The median age was 73 years (interquartile range25th-75th [IQR] 53-87 years) and 57% (913) were female. Overall mortality was 21.6% (348). The overall incidence of symptomatic TEs within 90 days of diagnosis was 1.8% (30 of 1621) occurring in 28 patients, including an incidence of pulmonary embolism of 0.9% (15, 95% confidence interval [CI] 0.60%-1.6%), deep venous thrombosis of 0.61% (10, 95% CI 0.2%-1%), ischemic stroke of 0.25% (4, 95% CI 0.09%-0.65%), and ischemic arterial events of 0.06% (1, 95% CI 0.008%-0.43%). No acute coronary syndrome events were recorded. The incidence of symptomatic TEs was significantly lower in the general ward than in intensive care units (1.2% vs 5.7%; p < .001). The median time since positive rt-PCR for SARS-CoV2 to symptomatic TE was 22.5 days (IQR 19-43 days). There was no significant difference in the proportion of patients receiving (53.6%) and not receiving thromboprophylaxis (66.5%) and the development of TEs. CONCLUSION: The overall incidence of symptomatic TEs among these patients was lower than the incidence previously reported.

Effect of the nO → π*C═O Interaction on the Conformational Preference of 1,3-Diketones: A Case Study of Riolozatrione Derivatives.

The cyclopropane ring-opening reaction of riolozatrione, a natural product obtained from Jatropha dioica, afforded a 2,2-disubstituted 1,3-cyclohexandione displaying an alkyl methyl ether group at position 5. The conformational analysis of this product showed a high preference for the trans-diaxial conformation in both solution and solid state. Such conformation was possible from the noncovalent intramolecular nX → π*C═O interactions (X = an element having an unshared electron pair), allowing the determination of the interaction energies. Since the nX → π*C═O interactions can be regarded as additive, the energy values ranged from 4.52 to 6.51 kcal mol-1 for each carbonyl group with a strong dependency on the interatomic distances. The rigorous analysis of the electron density in the topological theory of atoms in molecules framework clearly shows that the origin of O-C═O interactions are through the nO → π*C═O electron transfer mechanism. Such interactions are slightly weaker than a canonical hydrogen bond but seemingly stronger than a van der Waals interaction. This interaction must be considered as a stereoelectronic effect due the electronic transfer between the interacting groups, which are limited by their relative stereochemistry and can be represented by a bond-no bond interaction, causing the pyramidalization of the carbonyl, which is the charge acceptor group.

ARAMIS: From systematic errors of NGS long reads to accurate assemblies.

NGS long-reads sequencing technologies (or third generation) such as Pacific BioSciences (PacBio) have revolutionized the sequencing field over the last decade improving multiple genomic applications like de novo genome assemblies. However, their error rate, mostly involving insertions and deletions (indels), is currently an important concern that requires special attention to be solved. Multiple algorithms are available to fix these sequencing errors using short reads (such as Illumina), although they require long processing times and some errors may persist. Here, we present Accurate long-Reads Assembly correction Method for Indel errorS (ARAMIS), the first NGS long-reads indels correction pipeline that combines several correction software in just one step using accurate short reads. As a proof OF concept, six organisms were selected based on their different GC content, size and genome complexity, and their PacBio-assembled genomes were corrected thoroughly by this pipeline. We found that the presence of systematic sequencing errors in long-reads PacBio sequences affecting homopolymeric regions, and that the type of indel error introduced during PacBio sequencing are related to the GC content of the organism. The lack of knowledge of this fact leads to the existence of numerous published studies where such errors have been found and should be resolved since they may contain incorrect biological information. ARAMIS yields better results with less computational resources needed than other correction tools and gives the possibility of detecting the nature of the found indel errors found and its distribution along the genome. The source code of ARAMIS is available at https://github.com/genomics-ngsCBMSO/ARAMIS.git.

Monitoring Glyphosate- and Chlorimuron- resistant Conyza spp. Populations in Brazil.

Conyza species are important weeds in global agriculture, especially due to their capacity to evolve resistance to multiple herbicide mechanisms of action. We aimed to evaluate the frequency and distribution of resistance to glyphosate and chlorimuron-ethyl in Conyza spp. populations from Brazil. Seed samples were collected from grain production areas across nine Brazilian states over five consecutive years (2014 to 2018). Prior to resistance monitoring trials, dose-response assays were conducted to determine a single dose of glyphosate or chlorimuron-ethyl to discriminate resistant and susceptible populations. Resistance monitoring based on plant responses to the application of discriminatory doses of glyphosate (960 g ha-1) or chlorimuron-ethyl (20 g ha-1). Populations were classified as resistant, moderately resistant, or susceptible to either herbicide. While glyphosate resistance was highly frequent (71.2%) in all the five years, chlorimuron-ethyl resistant populations occurred at 39.8% of the total. The frequency of multiple resistance to both herbicides (35.3%) was proportional to the occurrence of chlorimuron-ethyl resistance (39.6%). Resistance to glyphosate and to chlorimuron-ethyl were found across all states evaluated.

The origin of the regiospecificity of acrolein dimerization.

Acrolein dimerization is a intriguing case since the reaction does not occur to form the electronically preferred regioisomeric adduct. Various explanations have been suggested to rationalize this experimental regioselectivity, however, none of these arguments had been convincing enough. In this work, the hetero Diels-Alder acrolein dimerization was theoretically investigated using DFT and MP2 methods. The influence of nucleophilic/electrophilic interactions and non-covalent interactions (NCI) in the regiospecificity of the reaction were analyzed. Our results show that the NCI at the transition state are the key factor controlling the regiospecificity in this reaction. Besides, we found that the choice of calculation method can have an effect on the prediction of the mechanism in the reaction, as all DFT methods forecast a one-step hetero Diels-Alder acrolein dimerization, while MP2 predicts a stepwise description for the lower energy reaction channel.