Novel mechanisms of diversity generation in Acinetobacter baumannii resistance islands driven by Tn7-like elements.

Mobile genetic elements play an important role in the acquisition of antibiotic and biocide resistance, especially through the formation of resistance islands in bacterial chromosomes. We analyzed the contribution of Tn7-like transposons to island formation and diversification in the nosocomial pathogen Acinetobacter baumannii and identified four separate families that recognize different integration sites. One integration site is within the comM gene and coincides with the previously described Tn6022 elements suggested to account for the AbaR resistance island. We established Tn6022 in a heterologous E. coli host and confirmed basic features of transposition into the comM attachment site and the use of a novel transposition protein. By analyzing population features within Tn6022 elements we identified two potential novel transposon-encoded diversification mechanisms with this dynamic genetic island. The activities of these diversification features were confirmed in E. coli. One was a novel natural gain-of-activity allele that could function to broaden transposition targeting. The second was a transposon-encoded hybrid dif-like site that parasitizes the host dimer chromosome resolution system to function with its own tyrosine recombinase. This work establishes a highly active Tn7-like transposon that harnesses novel features allowing the spread and diversification of genetic islands in pathogenic bacteria.

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.

Hybridization and introgression between Helicoverpa armigera and H. zea: an adaptational bridge.

BACKGROUND: Invasion of organisms into new ecosystems is increasingly common, due to the global trade in commodities. One of the most complex post-invasion scenarios occurs when an invasive species is related to a native pest, and even more so when they can hybridize and produce fertile progeny. The global pest Helicoverpa armigera was first detected in Brazil in 2013 and generated a wave of speculations about the possibility of hybridization with the native sister taxon Helicoverpa zea. In the present study, we used genome-wide single nucleotide polymorphisms from field-collected individuals to estimate hybridization between H. armigera and H. zea in different Brazilian agricultural landscapes. RESULTS: The frequency of hybridization varied from 15 to 30% depending on the statistical analyses. These methods showed more congruence in estimating that hybrids contained approximately 10% mixed ancestry (i.e. introgression) from either species. Hybridization also varied considerably depending on the geographic locations where the sample was collected, forming a 'mosaic' hybrid zone where introgression may be facilitated by environmental and landscape variables. Both landscape composition and bioclimatic variables indicated that maize and soybean cropland are the main factors responsible for high levels of introgression in agricultural landscapes. The impact of multiple H. armigera incursions is reflected in the structured and inbred pattern of genetic diversity. CONCLUSIONS: Our data showed that the landscape composition and bioclimatic variables influence the introgression rate between H. armigera and H. zea in agricultural areas. Continuous monitoring of the hybridization process in the field is necessary, since agricultural expansion, climatic fluctuations, changing composition of crop species and varieties, and dynamic planting seasons are some factors in South America that could cause a sudden alteration in the introgression rate between Helicoverpa species. Introgression between invasive and native pests can dramatically impact the evolution of host ranges and resistance management.

Effects of glyphosate on the non-target leaf beetle Cerotoma arcuata (Coleoptera: Chrysomelidae) in field and laboratory conditions.

This study aimed to assess the glyphosate application effects on the Cerotoma arcuata Oliver (Coleoptera: Chrysomelidae) population in glyphosate-resistant soybean crops. Field studies were conducted with glyphosate and the insecticide endosulfan to observe the effects of these pesticides on C. arcuata, on its damages in the crop and on the populations of natural enemies in glyphosate-resistant soybean crops. Moreover, the lethal and behavioral sublethal response of C. arcuata to glyphosate and endosulfan was conducted in the laboratory. The results of the field and laboratory experiments showed that glyphosate caused moderate toxicity and high irritability in C. arcuata and that endosulfan caused high toxicity and irritability. Therefore, the direct effect of glyphosate on C. arcuata was negative and does not explain the population increases of this pest in glyphosate-resistant soybean. However, the glyphosate also decreased the density of predators. Thus, the negative effect of glyphosate on the predators may be related to population increases of C. arcuata in glyphosate-resistant soybean crops, however, more studies are needed to better evidence this relationship. This study suggests that glyphosate can impact other non-target organisms, such as herbivorous insects and natural enemies and that the use of this herbicide will need to be carefully stewarded to prevent potential disturbances in beneficial insect communities in agricultural systems.

High frequency of CYP337B3 gene associated with control failures of Helicoverpa armigera with pyrethroid insecticides in Brazil.

Control failures with the use of pyrethroid insecticides have been reported frequently for populations of Helicoverpa armigera (Hübner) in Brazil, since its detection in 2013. Here, we confirmed and investigated the metabolic mechanisms of pyrethroid resistance in H. armigera populations from Brazil. Mortality of H. armigera populations was lower than 50% at the highest dose (10µg a.i./3rd instar larva) of the pyrethroids deltamethrin and fenvalerate in dose-response bioassays. Very low mortality (10 to 40%) was obtained at a diagnostic dose of 10µg a.i./larva for each pyrethroid in H. armigera populations collected from different agricultural regions in Brazil, from 2013 to 2016. In synergist bioassays, when larvae were treated with PBO synergist, the mortality of all populations tested was 100%. The frequency of the cytochrome P450 CYP337B3 gene was above 0.95 in all populations of H. armigera. We found only fourteen heterozygous H. armigera out of 497 individuals tested for this gene subfamily. Our results indicated that H. armigera populations from Brazil have different degrees of susceptibility to deltamethrin and fenvalerate, but all populations can be considered tolerant to pyrethroid insecticides. The chimeric P450 CYP337B3 enzyme is one of the main mechanisms of pyrethroid resistance in Brazilian H. armigera populations.

The Invasive Liriomyza huidobrensis (Diptera: Agromyzidae): Understanding Its Pest Status and Management Globally.

Liriomyza huidobrensis (Blanchard) is native to South America but has expanded its range and invaded many regions of the world, primarily on flowers and to a lesser extent on horticultural product shipments. As a result of initial invasion into an area, damage caused is usually significant but not necessarily sustained. Currently, it is an economic pest in selected native and invaded regions of the world. Adults cause damage by puncturing abaxial and adaxial leaf surfaces for feeding and egg laying sites. Larvae mine the leaf parenchyma tissues which can lead to leaves drying and wilting. We have recorded 365 host plant species from 49 families and more than 106 parasitoid species. In a subset of the Argentinian data, we found that parasitoid community composition attacking L. huidobrensis differs significantly in cultivated and uncultivated plants. No such effect was found at the world level, probably due to differences in collection methods in the different references. We review the existing knowledge as a means of setting the context for new and unpublished data. The main objective is to provide an update of widely dispersed and until now unpublished data, evaluate dispersion of the leafminer and management strategies in different regions of the world, and highlight the need to consider the possible effects of climate change on further regional invasions or expansions.

The first extensive analysis of species composition and abundance of stink bugs (Hemiptera: Pentatomidae) on soybean crops in Brazil.

BACKGROUND: Soybean is the third-greatest global commodity crop with respect to grain production, Brazil is the largest soybean producer in the world. We performed the first extensive survey including all the five main soybean cultivation regions in Brazil over three seasons (2018/2019, 2019/2020, and 2020/2021). A total of 2386 localities were sampled, corresponding to 145 municipalities in 11 states. Sampling was carried out between the R1 and R8 soybean growth stages, using a beating sheet. RESULTS: Fifteen species were recorded, with five species accounting for more than 99% of the sampled insects. The Neotropical brown stink bug, Euschistus heros (F.), was the most abundant species (82.4% of the adults and 84.1% of the nymphs overall), with differences in the mean abundance between soybean macroregions. The melacanthus green belly stink bug, Diceraeus melacanthus Dallas was the second most abundant species overall, followed by the brown winged stink bug, Edessa meditabunda (F.), the furcatus green belly stink bug, Diceraeus furcatus (F.) and the red-banded green stink bug, Piezodorus guildinii (Westwood). The relative abundance of each species differed between soybean macroregions. The mean abundance of nymphs and adults of Euschistus heros at different soybean reproductive stages showed an increase from early reproductive stages to the beginning of the late reproductive stages (R5 or R6). CONCLUSION: This large-scale assessment of stink bugs provides a basis for outlining integrated pest management programs and drives the development of monitoring and control strategies, as well as future studies investigating population dynamics over time and space in soybean fields. © 2024 Society of Chemical Industry.

Molecular insights on the historical dispersion of Piezodorus guildinii (Hemiptera: Pentatomidae) in Brazil.

Piezodorus guildinii (Westwood, 1837) (Hemiptera: Pentatomidae) is an important arthropod pest of soybean (Glycine max (L.) Merr.) throughout American continents. However, the historical events associated with its dispersion are poorly understood. In this study, we employed a phylogeographic approach to investigate the origin and demographic history of P. guildinii in Brazil. We analyzed the cytochrome c oxidase subunit I and Cytb gene sequences of P. guildinii individuals collected in Brazil's 5 soybean production macro-regions and cross-referenced this information with sequences available in public databases. Our findings support an older Caribbean basin establishment for the current genealogical strains of P. guildinii, with subsequent dispersion to Brazil around 0.97 Mya. No secondary dispersion of this species from the Caribbean region to soybean areas in Brazil was identified. The Brazilian populations of P. guildinii are genetically structured across the country's soybean macro-regions and show strong signals of continuous demographic and spatial expansion in Brazil, which may be accelerated by the soybean cropping landscape in the country. The populations from the northern region (MR5) are older than the Central and South populations. The signs of demographic expansion indicate that P. guildinii populations are increasing their effective size in soybean regions, which could reflect its importance as a soybean pest in the coming years.

Write a Researcher: a Pen Pal Outreach Program for Middle and High School Students.

The decision to pursue a science, technology, engineering, and/or math (STEM) career is often made in middle and high school, yet many students do not have access to resources or opportunities to navigate this career path. Without guidance, obtaining a job in STEM may seem like a daunting or impossible task. Here, we present Write a Researcher, a program wherein middle and high school students were paired with STEM professionals at Cornell University as pen pals. Through personalized handwritten letters, students her empowered with advice, encouragement, and knowledge to support their understanding of STEM fields, advanced degrees, and careers. We share Write a Researcher here to encourage others to establish similar programs at their own institutions.

Establishment of Sinoxylon anale Lesne (Coleoptera, Bostrichidae) in Brazil: Identification, Host Plants, Distribution, and Damage.

Damage from Sinoxylon anale Lesne, a woodboring beetle not previously known to be established in Brazil, was observed in young jabuticaba trees (Plinia cauliflora, Myrtaceae) in a nursery in the municipality of Laranjal Paulista, state of São Paulo. We immediately advised MAPA ("Ministério da Agricultura, Pecuária e Abastecimento") and collected samples from the nursery and from different hosts in nearby areas, to identify the specimens and investigate the dynamics of the infestation in the jabuticaba trees. Sinoxylon anale was also collected in ethanol-baited and ultraviolet-light traps and in dry branches of the native species pau-jacaré (Piptadenia gonoacantha, Fabaceae) and inga (Inga vera, Fabaceae), and the exotic pau-d'água (Dracaena fragrans, Asparagaceae) in the municipality of Piracicaba, state of São Paulo. These collections established that S. anale larvae and adults develop in dead branches of four new host plants. Taxonomic studies using morphological parameters and DNA barcoding confirmed the identification of S. anale. An illustrated key to the three Sinoxylon species now recorded in Brazil is provided, and the COI gene sequences have been made available in a public database. Sinoxylon anale probably attacked the young jabuticaba trees after they were killed by larvae of long-horned beetles (Cerambycidae). So far, S. anale has been found established only in two locations in the same area of the state of São Paulo.

Helping students see bacteria in 3D: cellular models increase student learning about cell size and diffusion.

In the microbial world, cell size and shape impact physiology, but students struggle to visualize spatial relationships between cells and macromolecules. In prokaryotic cells, cell size is limited by reliance on diffusion for nutrient uptake and the transport of nutrients within the cell. Cells must also meet a minimum size threshold to accommodate essential cellular components such as ribosomes and DNA. Using 3D printing allows for the creation of custom models that can be influential teaching tools in the biology classroom. This lesson uses 3D cell models to teach students enrolled in an introductory microbiology course about bacterial cell size and the biological importance of surface-area-to-volume ratio. During the lesson, students interact with 3D cell models and discuss a series of questions in small groups. Student learning was assessed using quantitative and qualitative student response data collected pre- and post-lesson. Student achievement of learning objectives, and their confidence in their knowledge of these concepts, improved post-lesson, and these gains were statistically significant. Our findings suggest that interacting with 3D-printed cell models improves student understanding about bacterial cell size and diffusion.

Integrative approach reveals the identity of Brazilian specimens previously recognized as Anastrepha dissimilis Stone, 1942 (Diptera: Tephritidae).

Anastrepha dissimilis is currently considered to be widely distributed in Brazil, occurring in 20 of 27 states. However, morphological differences between the holotype (from Plaisance, Haiti) and a paratype (from Pernambuco, Brazil) suggest that the Brazilian specimens are not A. dissimilis, because their aculeus tip is similar to the paratype not to the holotype. Therefore, considering the importance of integrative taxonomy for species delimitation, we used geometric and linear morphometrics and cytochrome c oxidase subunit I sequences integrated with the morphology of the aculeus tip to clarify the identity of populations previously identified as A. dissimilis from multiple Brazilian localities. Morphological data show a uniform pattern among the Brazilian populations, with some variation among specimens from the south and northeast. In addition, the geometric and linear morphometrics suggest considerable geographic variation among these populations, suggesting the existence of at least two morphs. The molecular analysis revealed that specimens from Brazil previously identified as A. dissimilis belong to Anastrepha chiclayae Greene, with a genetic distance ranging from 0.00 to 0.015%. According to our integrative analyses, specimens from Brazil formerly identified as A. dissimilis actually are A. chiclayae. Therefore, this is the first record of A. chiclayae in Brazil, and we also report that A. dissimilis does not occur in Brazil.

The genome sequence of the Neotropical brown stink bug, Euschistus heros provides insights into population structure, demographic history and signatures of adaptation.

The Neotropical brown stink bug, Euschistus heros, is a major pest of soybean in South America. The importance of E. heros as a pest has grown significantly in recent times due to increases in its abundance and range, and the evolution of insecticide resistance. Recent work has begun to examine the genetic diversity, population structure, and genetic mechanisms of insecticide resistance in E. heros. However, to date, investigation of these topics has been hampered by a lack of genomic resources for this species. Here we address this need by assembling a high-quality draft genome for E. heros. We used a combination of short and long read sequencing to assemble an E. heros genome of 1.4 Gb comprising 906 contigs with a contig N50 of 3.5 MB. We leveraged this new genomic resource, in combination with genotyping by sequencing, to explore genetic diversity in populations of this species in Brazil and identify genetic loci in the genome which are under selection. Our genome-wide analyses, confirm that there are two populations of E. heros co-occurring in different geographical regions in Brazil, and that, in certain regions of the country these populations are hybridizing. We identify several regions of the genome as under selection, including markers associated with putative insecticide resistance genes. Taken together, the new genomic resources generated in this study will accelerate research into fundamental aspects of stinkbug biology and applied aspects relating to the sustainable control of a highly damaging crop pest.

A Molecular Marker to Identify Spodoptera frugiperda (JE Smith) DNA in Predators' Gut Content.

Spodoptera frugiperda is a serious pest of maize and other crops worldwide. The integration of control tactics is recommended for S. frugiperda suppression because reports of insecticide and Btplant-resistance are frequent. Biological control agents would be an alternative to improve S. frugiperda control in agricultural areas. We constructed a species-specific molecular marker to detect S. frugiperda DNA in predators' gut content and estimated the predation rates of ladybugs and earwigs on S. frugiperda in maize crops. Predators were sampled in Pirassununga, São Paulo state, Brazil, in 2020 and 2021. Using the species-specific molecular marker in laboratory conditions, we estimated the half-life time to detect S. frugiperda DNA in the gut contents of Hippodamia convergens as 6.16 h and Doru luteipes as 25.72 h. The weekly predation rate of S. frugiperda by predators in maize crop varied from 0 to 42.1% by ladybugs and from 0 to 9.2% by D. luteipes. Predation events on S. frugiperda by predators were more frequent during the maize reproductive stage. Our results confirmed that predators might contribute to S. frugiperda suppression in maize fields. However, further studies of prey-predator interactions and agricultural landscapes are essential for a better understanding of predator dynamics in crops.

"Unmasking the Villain": Integrative Taxonomy Reveals the Real Identity of the Key Pest (Thysanoptera: Thripidae) of Peanuts (Arachis hypogaea L.) in South America.

The peanut thrips, Enneothrips enigmaticus sp. n., is the key pest of Arachis hypogaea L. in South America, where it can cause yield losses of up to 85%. This species has historically been identified as Enneothrips flavens, but access to the holotype of this species and freshly collected material from southeastern and northern Brazil revealed that specimens commonly collected on peanut crops are not conspecific with E. flavens. Biological, molecular, and morphological assessments were carried out and led to the conclusion that the key pest of A. hypogaea belongs to a previously undescribed species: Enneothrips enigmaticus sp. n.

[Oral paracoccidiodomycosis in an immunocompetent woman: a case report and literature review]. / Paracoccidiodomicosis oral en mujer inmunocompetente: a propósito de un caso y revisión de la literatura.

Paracoccidioidomycosis is a progressive, chronic, systemic disease which is the second most common form of mycosis in South America, affecting approximately 10million people in this region. It occurs most commonly in adult male farmers and mainly affects the lungs. Oral paracoccidioidomycosis is the second most frequent chronic presentation. We report the case of an immunocompetent female patient whose oral mucosae was infected with paracoccidium and discuss oral paracoccidium.

Regional pest suppression associated with adoption of Cry1Ac soybean benefits pest management in tropical agriculture.

BACKGROUND: Bacillus thuringiensis (Bt) crops have been adopted worldwide, providing high-level protection from insect pests. Furthermore, Bt crops preserve natural enemies, promote higher yield, and economically benefit farmers. Although regional pest suppression by widespread Bt crop adoption has been observed in temperate regions, this possibility remains uncertain in tropical areas due to the high diversity of alternative hosts and mild winters. RESULTS: Evidence of regional reduction in insecticide use across areas was observed in Brazil where Cry1Ac soybean has been grown since 2013, with up to 50% reduction in the number of insecticide sprays for managing lepidopteran pests on non-Bt soybean observed at specific locations from 2012 to 2019. Pest monitoring data from four mesoregions across 5 years of commercial plantings of Cry1Ac soybean from December 2014 to July 2019 showed reduced numbers of Chrysodeixis includens moths captured in pheromone traps across years at all locations. The number of Helicoverpa spp. moths captured also was reduced at three locations. CONCLUSION: We provide evidence for regional suppression of lepidopteran pests and reduced insecticide use with the widespread adoption of Cry1Ac soybean in Brazil, bringing economic, social and environmental benefits. © 2022 Society of Chemical Industry.

Euschistus crenator (Fabricius) (Hemiptera: Pentatomidae): a New Invasive Species on Soybean Fields in Northern Brazil.

The expansion of soybean Glycine max (L.) Merrill in South America has provided an abundant host to the native arthropod fauna. Stink bugs (Heteroptera: Pentatomidae) are severe pests on soybean crops due to their feeding activities. Several native species have been recorded on this crop, with the widespread Neotropical brow stink bug Euschistus heros (Fabricius) recognized as the key pest in most of its distribution. Here, we report for the first time Euschistus crenator (Fabricius) as a new invasive species on soybean fields in Northern Brazil. We collected the species at Pará state (2°38'32.2″S 54°55'56.1″W and 4°06'31.2″S 54°55'01.9″W) and Roraima state (2°39'41.3″N 60°46'58.9″W and 3°00'44.6″N 60°22'32.9″W). The latter represents a new state record, and the first represents new locality records, however, both representing the first soybean host record for the species. The distribution of E. crenator ranges from southern US (AZ, CA, FL, and TX) to north South America, mostly between the Tropics of Cancer and Capricorn. Despite overlap in distribution, we did not find E. crenator and E. heros simultaneously on soybean crops in the North region (Amazon Forest) of Brazil. Euschistus crenator was able to complete its life cycle and had viable offspring on soybean plants, with development parameters similar to E. heros.

Reproductive Patterns Drive the Gene Flow and Spatial Dispersal of Euschistus heros (Hemiptera: Pentatomidae).

Euschistus heros (Hemiptera: Pentatomidae) has two allopatric strains with a hybrid zone in central Brazil. Asymmetric dispersal and gene flow between these strains of E. heros have been observed, where the South strain (SS) moves more quickly to the northern regions of the country than the North strain (NS) to the southern areas. In addition, SS generally has a bigger body size and presents dark brown coloration, and NS is usually smaller in size and presents light brown coloration. Here, we studied the reproductive behavior and tested for the presence of assortative mating and reproductive barriers between the two allopatric strains of E. heros. Nonrandom mating was observed in the SS strain based on mating choice trials and the reproductive isolation indexes. SS females and males prefer to mate with their co-specific (same strain) partner, while NS insects showed no mating preference. The insect's pronotum width was positively associated with the mating choice suggesting size-assortative mating in E. heros. Reciprocal crosses between strains yielded similar reproductive outputs when compared with pure strain crosses, suggesting similar fitness of hybrid pure strains. The asymmetric gene flow in the hybridization zone that favors SS seems to be associated with the reproductive behavior of the species, which favors the typical phenotype found in the SS populations.

Integrative taxonomy and phylogeography of Telenomus remus (Scelionidae), with the first record of natural parasitism of Spodoptera spp. in Brazil.

The egg parasitoid Telenomus remus (Hymenoptera: Scelionidae) has been investigated for classical and applied biological control of noctuid pests, especially Spodoptera (Lepidoptera: Noctuidae) species. Although T. remus was introduced into Brazil over three decades ago for classical biological control of S. frugiperda, this wasp has not been recorded as established in corn or soybean crops. We used an integrative approach to identify T. remus, combining a taxonomic key based on the male genitalia with DNA barcoding, using a cytochrome c oxidase subunit I mitochondrial gene fragment. This is the first report of natural parasitism of T. remus on S. frugiperda and S. cosmioides eggs at two locations in Brazil. We also confirmed that the T. remus lineage in Brazil derives from a strain in Venezuela (originally from Papua New Guinea and introduced into the Americas, Africa, and Asia). The occurrence of T. remus parasitizing S. frugiperda and S. cosmioides eggs in field conditions, not associated with inundative releases, suggests that the species has managed to establish itself in the field in Brazil. This opens possibilities for future biological control programs, since T. remus shows good potential for mass rearing and egg parasitism of important agricultural pests such as Spodoptera species.