Morphology of the Mandibular and Intramandibular Glands of Army Ant Workers of Labidus praedator (Smith 1858) and Labidus coecus (Latreille 1802) (Formicidae: Dorylinae).

Social insects are characterized by having a wide diversity of exocrine glands, with highlights for ants with about 85 glands spreading throughout the body. The mandibular and intramandibular glands are associated with the production of pheromones. The army ants (Dorylinae) play an important role in the structure of the invertebrate community because they are efficient predators and provide suitable conditions for various animals following their invasions in the food search. Labidus coecus (Latreille) is an underground-ameliorating ant and Labidus praedator (Smith) is a generalist surface predator which can deplete invertebrate biomass by up to 75%. This work investigated the morphology of the mandibular and intramandibular glands of L. praedator and L. coecus workers. The glands were analyzed by light microscopy, histochemistry, and scanning electron microscopy. The mandibular and intramandibular glands of the two species were classified as class III glands. The data on the morphology of the mandibular glands has revealed that they have characteristics in common with other subfamilies. The intramandibular glands of the two species of Labidus have similar morphology and chemical composition, which indicates that the components of these glands can have the same function despite their different habits.

Effect of Induced Pulmonary Arterial Hypertension on Testicular Parameters of Wistar Rats Subjected to Resistance Exercise Training.

Pulmonary arterial hypertension (PAH) is characterized by elevated arterial pressure and vascular resistance. PAH may cause alterations in the microcirculation of several organs, including the kidney, liver, brain, and testes. However, it remains unclear whether monocrotaline-induced PAH exerts detrimental effects on animal testes. Thus, we analyzed the impact of PAH on testicular morphology and function. Additionally, we investigated the effect of resistance exercise training (RT) on testicular parameters in PAH rats. Eight healthy Wistar rats and eight PAH rats were subjected to RT training for 30 days; the other PAH and healthy rats (n = 8/group) did not exercise. PAH rats had lower reproductive organ weight, serum testosterone levels, testicular glucose, and nitric oxide (NO) levels, Leydig cell parameters, tubular morphometry, germ cell counts, and daily sperm production than healthy animals did. The practice of RT attenuated the negative impact of PAH on the relative weights of the testes and epididymides, Leydig cell number, nuclear volume, testicular NO levels, and seminiferous epithelium architecture. Moreover, RT positively influenced testosterone levels in PAH animals. We conclude that PAH exerts deleterious effects on testicular histology and function. However, RT can be beneficial to the PAH-affected testicular parameters.

Hemocyte morphology of worker subcastes of the leaf-cutting ant Atta sexdens rubropilosa (Hymenoptera: Formicidae).

Hemocytes are cells present in the hemolymph of insects that play a role in combating invasive pathogens, ensuring defense by the immune system in these organisms. While the types of hemocytes are well known in some insect representatives, data on these cells in Hymenoptera are limited to certain bees and wasps, with little information available for ants. Among ants, the genus Atta has environmental and economic importance, forming highly organized colonies consisting of the queen and workers, with the latter subdivided into subcastes: gardeners, waste removers, foragers, and soldiers, which are exposed to different pathogens. This study describes the morphology of hemocytes in the worker subcastes of Atta sexdens rubropilosa. Hemolymph samples from the ant were submitted to light, confocal, and scanning electron microscopy analyses. Five types of hemocytes were identified in the hemolymph of all ant subcastes, including prohemocytes, oenocytoids, spherulocytes, plasmatocytes, and granulocytes. They exhibited nuclei with a predominance of decondensed chromatin. The granulocytes were the most abundant cell type in the subcastes, followed by prohemocytes, plasmatocytes, oenocytoids, and spherulocytes. Phagocytosis assays reveal that plasmatocytes and granulocytes are the main phagocytic cells in all castes evaluated. This study fills an important gap in understanding the immune response in this ant species.

The fungicide azoxystrobin causes histopathological and cytotoxic changes in the midgut of the honey bee Apis mellifera (Hymenoptera: Apidae).

Apis mellifera is an important bee pollinating native and crop plants but its recent population decline has been linked to the use of pesticides, including fungicides that have been commonly classified as safe for bees. However, many pesticides, in addition to direct mortality cause sublethal effects, including damage to target selective honey bee organs. The midgut is the organ responsible for the digestion and absorption of nutrients and the detoxification of ingested substances, such as pesticides. This study evaluated the histopathological and cytotoxic changes in the midgut of A. mellifera workers caused by the pesticide azoxystrobin. The limit-test was performed, and a 100 µg a.i./bee dose was administered orally and midgut analyzed with light and transmission electron microscopies after 24 h and 48 h of pesticide exposure. The midgut of the control bees has a single layer of digestive cells, with spherical nuclei, nests of regenerative cells, and the lumen coated with the peritrophic matrix. The bees fed on azoxystrobin showed morphological changes, including intense cytoplasm vacuolization and cell fragments released into the gut lumen. The protein detection test showed greater staining intensity in the nests of regenerative cells after 24 h of exposure to azoxystrobin. The occurrence of damage to the midgut in A. mellifera exposed to azoxystrobin indicates that although this fungicide has been classified as low toxicity for bees, it has sublethal effects in the midgut, and effects in other organs should be investigated.

Larval and adult digestive tract of the carrion beetle Oxelytrum discicolle (Brullé, 1840) (Coleoptera: Silphidae).

Oxelytrum discicolle is a necrophagous beetle occurring in Central and South America, with potential use in forensic entomology for investigations in the context of legal medicine. The present work aimed to describe the morphology of the digestive tract of larvae and adults and contributes to the knowledge about the digestion associated with necrophagy. In the three larval instars, the foregut is short and narrow, the midgut is a dilated tube, elongated with a smooth surface, and the hindgut is narrow and long, with small lateral projections and a dilated terminal region. The gut epithelium in the second and third instar larvae is vacuolated in the mid- and hindgut, with high production of apocrine secretions in the midgut lumen. In adults, the foregut is short, with small spines in the cuticular intima that covers the flattened epithelium. The midgut is dilated, with many short gastric caeca with regenerative cells in the blind portion, which differentiate in digestive columnar cells towards the midgut lumen. The hindgut is long and narrow, with an enlarged distal portion with folded epithelium lined by a thin cuticle. The histochemical tests reveal the absence of protein storage granules in the gut epithelium of larvae and adults. The gut characteristics of the carrion beetle O. discicolle are similar to those of other predatory and phytophagous Coleoptera, which may indicate that ancestry may influence the alimentary canal morphology more than the feeding habits.

Differential gene expression by RNA-seq during Alzheimer's disease-like progression in the Drosophila melanogaster model.

Alzheimer's disease (AD) is characterized by progressive, irreversible loss of memory and cognitive function. Drosophila melanogaster and other animal models are used to study several diseases, in order to elucidate unknown mechanisms and develop potential therapies. Molecular studies require biological samples and, for neuropathologies such as AD biopsy of the human brain, are invasive and potentially damaging. The solution is to use animal models, such as D. melanogaster, which is a model organism that can replace mammalian organisms in such studies. In this study, we evaluated the climbing ability and differential gene expression during AD progression due to the amylodoigenic pathway using RNA-seq, and we performed an in silico analysis of a fruit fly AD-like GFP (Green Fluorescent Protein) model with GFP expression in the pan-neural elav driver. A total of 1388 genes were differentially expressed in all analyzed groups. The main pathways related to those Differentially Expressed Genes (DEGs) during aging and AD progression were evaluated using the fly genes and human orthologs, in order to link genomic information to higher-order functional information with gene pathway mapping. We identified pathways present in all analyzed groups, such as metabolic pathways, ribosomal pathways, proteasome pathways and immune system pathways. Some of the genes were validated by qPCR. Knockdown of CG17754 gene by RNAi promoted degeneration in the fly eye, validating these findings in vivo. The identification of similarities in molecular pathways between the transgenic fly AD-like GFP model and mammals related to AD provides new insights into the use of this fly in screening novel anti-AD drugs.

Acute oral exposure to imidacloprid induces apoptosis and autophagy in the midgut of honey bee Apis mellifera workers.

The honey bee Apis mellifera is an important pollinator that increases the yield and quality of crops. In recent years, honey bee populations have declined in some parts of the world, which has been associated with several causes, including pesticides used in agriculture. Neonicotinoids are neurotoxic insecticides widely used in the world with systemic action mode contaminating nectar and pollen that may be consumed by bees. This study evaluated the side effects of imidacloprid in the midgut of A. mellifera after acute oral exposure. Toxicity, histopathology, cytotoxicity, and expression of autophagy-related gene atg1 were evaluated in honey bee workers orally exposed to imidacloprid. The estimated imidacloprid LC50 was 1.44 mg L-1. The midgut epithelium of bees fed on imidacloprid LC50 has the occurrence of cytoplasm vacuoles, enlarged intercellular spaces, disorganization of the striated border, and nuclear pyknosis, with an organ injury index that increases with time exposure. The midgut digestive cells of treated bees have apical protrusions, damaged mitochondria, and autophagosomes that were characterized for content with organelle debris and high expression of atg1. These features indicate the occurrence of high cell death in the midgut of workers exposed to imidacloprid, which may affect the digestibility the physiology of the insect.

Biochemical and morphological characterization of freshwater microalga Tetradesmus obliquus (Chlorophyta: Chlorophyceae).

Tetradesmus is a microalgal genus with biotechnological potential due to its rapid production of biomass, which is plenty in proteins, carbohydrates, lipids, and bioactives. However, its morphology and physiology need to be determined to guide better research to optimize the species cultivation and biocompounds processing. Thus, this study describes the biochemistry and morphology of the strain Tetradesmus obliquus BR003, isolated from a sample of freshwater reservoirs in a Brazilian municipality. In the T. obliquus BR003 dry biomass, we identified 61.6% unsaturated fatty acids, and 3.4% saturated fatty acids. Regarding other compounds, 28.50 ± 1.47 g soluble proteins/100 g, 0.14 ± 0.009 g carotenoids/100 g, 0.76 ± 0.013 g chlorophyll a/100 g, and 0.42 ± 0.015 g chlorophyll b/100 g with a chlorophyll a/b ratio of 1.8 were detected. The main chemical elements found were S, Mg, and P. The cells of BR003 were elliptically curved at the ends and without appendages. Histochemical tests showed carbohydrates distributed in the cytoplasm and pyrenoids, some lipid droplets, and proteins. The cytoplasm is rich in vacuoles, rough endoplasmic reticulum, mitochondria, and chloroplasts. The nucleus has a predominance of decondensed chromatin, and the cell wall has three layers. Chloroplasts have many starch granules and may be associated with a spherical central pyrenoid. To the best of our knowledge, this was the first biochemical description combined with ultrastructural morphological characterization of the strain T. obliquus BR003, grown under standard conditions, to demonstrate specific characteristics of the species.

Handmade face mask can be sterilized without compromising their efficacy / Máscara facial artesanal pode ser esterilizada sem comprometer sua eficácia / La mascarilla facial hecha a mano se puede esterilizar sin comprometer su eficácia

Background and Objectives: COVID-19 caused by SARS-CoV-2 is transmitted by contact, droplets and aerosols. The World Health Organization recommends the mandatory use of surgical masks for health professionals and encourages countries to adhere to their use, en masse, in order to minimize the transmission of the virus. Since the lack of this personal protective equipment is a cause for concern, the objective of this study was to evaluate the characteristics of facial masks regarding (i) the mechanical properties of elongation, rupture stress and resistance to air passage and (ii) the morphometric properties of thickness, fiber diameter and pore distribution after autoclave sterilization. Methods: The masks were made in TNT Spunbonded (100% polypropylene, 60 g/m2 ), autoclaved at 70 ºC for 5 minutes and stored in plastic films at room temperature. Then, the mechanical properties were determined in an Instron universal testing machine and Gurley type automatic densimeter and the morphometric properties in a semi-automatic thickness gauge and scanning electron microscope. Results: It was observed that a cycle of sterilization of facial masks, by moist heat under pressure, increased the blanket's stiffness, did not produce physical damage and did not reduce the blanket's barrier capacity. Conclusion: The sterilization of face masks made of TNT can be considered a strategy to increase safety in their production and use.(AU)

Justificativa e Objetivos: A COVID-19 causada pelo SARS-CoV-2 é transmitida pelo contato, por gotículas e por aerossóis. A Organização Mundial da Saúde recomenda a obrigatoriedade do uso de máscaras cirúrgicas aos profissionais da saúde e incentiva os países a aderirem ao seu uso, em massa, a fim de minimizar a transmissibilidade do vírus. Posto que a falta desse equipamento de proteção individual causa preocupação, o objetivo deste trabalho foi avaliar as características de máscaras faciais quanto (i) às propriedades mecânicas alongamento, tensão de ruptura e resistência a passagem de ar e (ii) às propriedades morfométricas espessura, diâmetro das fibras e distribuição de poros após esterilização em autoclave. Métodos: As máscaras foram confeccionadas em TNT Spunbonded (100% polipropileno, 60 g/m2), autoclavadas a 70 ºC por 5 minutos e armazendadas em filmes plásticos a temperatura ambiente. Na sequência, as propriedades mecânicas foram determinadas em máquina de teste universal Instron e densímetro automático tipo Gurley e as propriedades morfométricas em medidor de espessura semiautomático e microscópio eletrônico de varredura. Resultados: Observou-se que um ciclo de esterilização das máscaras faciais, por calor úmido sob pressão, promoveu o aumento da rigidez da manta, não produziu danos físicos e não diminuiu a capacidade de barreira da manta. Conclusão: A esterilização de máscaras faciais confeccionadas em TNT pode ser considerada uma estratégia para aumentar a segurança na sua produção e uso.(AU)

Antecedentes y objetivos: El COVID-19 causado por el SARS-CoV-2 se transmite por contacto, gotitas y aerosoles. La Organización Mundial de la Salud recomienda el uso obligatorio de mascarillas quirúrgicas para los profesionales de la salud y alienta a los países a adherirse a su uso, en masa, con el fin de minimizar la transmisión del virus. Dado que la falta de este equipo de protección personal es motivo de preocupación, el objetivo de este estudio fue evaluar las características de las máscaras faciales en cuanto a (i) las propiedades mecánicas de elongación, tensión de rotura y resistencia al paso del aire y (ii) la morfometría propiedades de espesor, diámetro de fibra y distribución de poros después de la esterilización en autoclave. Métodos: Las máscaras se fabricaron en TNT Spunbonded (100% polipropileno, 60 g / m2), se esterilizaron en autoclave a 70 ºC durante 5 minutos y se almacenaron en películas plásticas a temperatura ambiente. Posteriormente, se determinaron las propiedades mecánicas en una máquina de ensayo universal Instron y densímetro automático tipo Gurley y las propiedades morfométricas en un medidor de espesor semiautomático y microscópio electrónico escaneando.Resultados: Se observó que un ciclo de esterilización de mascarillas faciales, por calor húmedo a presión, incrementó la rigidez de la manta, no produjo daño físico y no redujo la capacidad barrera de la manta. Conclusión: La esterilización de mascarillas faciales fabricadas con TNT puede considerarse una estrategia para aumentar la seguridad en su producción y uso.(AU)

Morphology and composition of the midgut bacterial community of Scaptocoris castanea Perty, 1830 (Hemiptera: Cydnidae).

The burrower bug Scaptocoris castanea is an important soybean and pasture pest in Brazil, with an underground habit feeding directly on the sap of the roots. Underground habit hinders control and knowledge of the biology and physiology of this pest. This study describes the anatomy, histology, ultrastructure and symbionts of the midgut of S. castanea. The midgut of S. castanea is anatomically divided into five regions (ventricles). Ventricles 1-3 are similar between males and females, with cells specialized in digestion and absorption of nutrients, water transport and homeostasis. Ventricle 4 has squamous epithelium forming crypts and harboring bacteria in the lumen. Ventricle 5 of males is small with cells containing apical microvilli and broad basal folds with many openings for hemocoel, while in females, this region of the midgut is well developed and colonized by intracellular bacteria, characterizing bacteriocytes. The main bacteria are Gammaproteobacteria. The results show sexual dimorphism in ventricle 5 of the midgut of S. castanea, with formation of bacteriocytes in the females, while the other regions are involved in digestive processes in both sexes.

Anatomy, Histology, and Ultrastructure of Salivary Glands of the Burrower Bug, Scaptocoris castanea (Hemiptera: Cydnidae).

The burrower bug Scaptocoris castanea Perty, 1830 (Hemiptera: Cydnidae) is an agricultural pest feeding on roots of several crops. The histology and ultrastructure of the salivary glands of S. castanea were described. The salivary system has a pair of principal salivary glands and a pair of accessory salivary glands. The principal salivary gland is bilobed with anterior and posterior lobes joined by a hilus where an excretory duct occurs. The accessory salivary gland is tubular with a narrow lumen that opens into the hilus near the excretory duct, suggesting that its secretion is stored in the lumen of the principal gland. The cytoplasm of the secretory cells is rich in the rough endoplasmic reticulum, secretory vesicles with different electron densities and mitochondria. At the base of the accessory gland epithelium, there were scattered cells that do not reach the gland lumen, with the cytoplasm rich in the rough endoplasmic reticulum, indicating a role in protein production. Data show that principal and accessory salivary glands of S. castanea produce proteinaceous saliva. This is the first morphological description of the S. castanea salivary system that is similar to other Hemiptera Pentatomomorpha, but with occurrence of basal cells in the accessory salivary gland.

Pyriproxyfen, a juvenile hormone analog, damages midgut cells and interferes with behaviors of Aedes aegypti larvae.

Juvenile hormone analogs (JHA) are known to interfere with growth and biosynthesis of insects with potential for insecticide action. However, there has been comparatively few data on morphological effects of JHA on insect organs. To determine pyriproxyfen effects on Aedes aegypti larvae, we conducted toxicity, behavioral bioassays and assessed ultrastructural effects of pyriproxyfen on midgut cells. A. aegypti larvae were exposed in aqueous solution of pyriproxyfen LC50 concentrations and evaluated for 24 h. This study fulfilled the toxic prevalence of pyriproxyfen to A. aegypti larvae (LC50 = 8.2 mg L-1). Behavioral observations confirmed that pyriproxyfen treatment significantly changes swimming behavior of larvae, limiting its displacement and speed. The pyriproxyfen causes remarkable histopathological and cytotoxic alterations in the midgut of larvae. Histopathological study reveals presence of cytoplasmic vacuolization and damage to brush border of the digestive cells. The main salient lesions of cytotoxic effects are occurrence of cell debris released into the midgut lumen, cytoplasm rich in lipid droplets, autophagosomes, disorganized microvilli and deformed mitochondria. Data suggest that pyriproxyfen can be used to help to control and eradicate this insect vector.

Male reproductive tract and spermatozoa ultrastructure in the grasshopper Orphulella punctata (De Geer, 1773) (Insecta, Orthoptera, Caelifera).

Identification Orphulellini grasshoppers (Acrididae: Gomphocerinae) species has been difficult due to high polymorphism rate. Orphulella Giglio-Tos, 1894 is a genus with widespread geographical distribution and poor descriptions. Orphulella punctata (De Geer, 1773) has an extensive record of occurrence and available information about the phallic complex, however, there is poor data describing other parts of the male reproductive tract. The objective of this study was characterizes the internal organs of the male reproductive system and spermatozoa of O. punctata. Orphulella punctata testes are of Fountain type, each having only four follicles. Spermatozoa into the seminal vesicle are arranged in bundles with c.a. 2320 µm length, with a nucleus 110 µm long. The spermatozoa are covered by a glycocalyx, the nucleus is cylindrical with condensed chromatin and connected to the flagellum by a dense and lamellar centriole adjunct. The axoneme have 9 + 9 + 2 pattern and present two symmetrical mitochondrial derivatives. A fibrous net and two flat membranous cisternae fill the space between the axoneme and mitochondrial derivatives. This is the first description of the reproductive system of a Gomphocerinae representative.

Sperm morphology of the leafhopper Diaphorina citri Kuwayama (Hemiptera: Sternorrhyncha: Psylloidea: Liviidae).

In this study, by using light and electron microscopy, we describe the sperm morphology of the leafhopper Diaphorina citri, a serious pest of citrus throughout the world. In this species the sperm measures 538.49±8.75µm in length, and as observed in psylloids, the sperm, when manipulated, opens into two filaments, one of which is attached to the nuclear base and the other becomes free. Along the flagellum, and only of it, there are lateral projections, about 2µm in length. Furthermore, at the end of the flagellum three appendages, with approximately 7µm in length, are observed. The head region is formed by the nucleus with compact chromatin, and, parallel to it, a structure of median electron density that extends about 25µm in length ahead of the nuclear tip. The flagellum consists of an axoneme with a 9+9+2 microtubule arrangement, two mitochondrial derivatives, and two accessory bodies each with two regions of different electron density. The presence of lateral projections is a characteristic observed in other Sternorrhyncha. As seen previously, the sperm opening in two filaments, when manipulated, was observed only in Psylloidea, and the presence of the three appendices at the end of the flagellum distinguishes D. citri from the other Psylloidea species studied.