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.

Hepatitis C-Associated Osteosclerosis: Improvement After Treatment with Sofosbuvir, Daclatasvir, and Ibandronate: Case Report and Literature Review.

Hepatitis C-associated osteosclerosis (HCAO) remains a rare condition despite the growing prevalence of hepatitis C virus (HCV) infection worldwide. Since the first case reported in 1992, this is the twenty-second case described. Patients with HCAO present with severe bone pain and elevated serum levels of bone markers, especially alkaline phosphatase (ALP), with increased bone density. We report here the case of a 59-year-old man with generalized bone pain and diagnosis of HCV infection. Biochemical tests showed elevated bone turnover markers, specifically, ALP, carboxy-terminal collagen crosslinks and osteocalcin. Imaging studies revealed generalized bone sclerosis. Bone mineral density was elevated in all validated sites. His clinical symptoms and bone-related findings were attributed to HCAO. He was sequentially treated with cholecalciferol, prednisone, sofosbuvir associated with daclatasvir and ibandronate, and progressed with undetectable viral load after HCV treatment, normalization of ALP levels after introduction of ibandronate, and pain improvement 1 year after discontinuation of the bisphosphonate. Bone pain complaints must be investigated in patients with HCV. HCAO is a differential diagnosis of increased bone mass.

Assessment of Preoperative Endometrial Histopathological Sampling as a Predictor of Final Surgical Pathology in Endometrial Cancer.

OBJECTIVE: To evaluate the agreement between the histopathological diagnoses of preoperative endometrial samples and surgical specimens and correlate the agreement between the diagnoses with the impact on surgical management and the survival of patients with endometrial adenocarcinomas. METHODS: Sixty-two patients treated for endometrial cancer at a university hospital from 2002 to 2011 were retrospectively evaluated. The histopathological findings of preoperative endometrial samples and of surgical specimens were analyzed. The patients were subjected to hysterectomy as well as adjuvant treatment, if necessary, and clinical follow-up, according to the institutional protocol. Lesions were classified as endometrioid tumor (type 1) grades 1, 2, or 3 or non-endometrioid carcinoma (type 2). RESULTS: The agreement between the histopathological diagnoses based on preoperative endometrial samples and surgical specimens was fair (Kappa: 0.40; p < 0.001). However, the agreement was very significant for tumor type and grade, in which a higher concordance occurred at a higher grade. The percentage of patients with lymph nodes affected was 19.2%. Although most patients presenting with disease remission or cure were in the early stages (90.5%), there were no significant differences between those patients who had a misdiagnosis (11/16; 68.8%) and those who had a correct diagnosis (25/33; 75.8%) based on preoperative endometrial sampling (p = 0.605). CONCLUSION: Our findings corroborate the literature and confirm the under staging of preoperative endometrial samples based on histopathological assessment, especially for lower grade endometrial tumors. We suggest that the preoperative diagnosis should be complemented with other methods to better plan the surgical management strategy.

OBJETIVO: Avaliar a concordância entre os diagnósticos histopatológicos de amostras endometriais pré-operatórias e cirúrgicas de pacientes com adenocarcinomas endometriais e avaliar o impacto da concordância entre os diagnósticos no planejamento cirúrgico e sobrevida das pacientes. MéTODOS: Dados de 62 pacientes com câncer de endométrio operadas entre 2002 a 2011 em um hospital universitário foram avaliadas retrospectivamente. As pacientes foram submetidas à histerectomia e tratamento adjuvante, se necessário, e acompanhadas clinicamente de acordo com o protocolo institucional. Foram avaliados os resultados das análises histopatológicas das amostras endometriais pré-operatórias e cirúrgicas. As lesões foram classificadas como tumor endometrioide (tipo 1) graus 1, 2 ou 3 ou carcinoma não endometrioide (tipo 2). RESULTADOS: De modo geral, houve uma concordância baixa entre os diagnósticos histopatológicos das amostras endometriais pré-operatórias e cirúrgicas (Kappa: 0,40; p < 0,001). Entretanto, uma alta concordância entre os diagnósticos foi observada nos tumores de graus mais elevados. Comprometimento de linfonodos ocorreu em 19,2% das pacientes e a maioria das que apresentaram remissão ou cura foram diagnosticadas nos estágios iniciais da doença (90,5%). Não houve diferença significativa na taxa de remissão ou cura entre as pacientes que tiveram concordância (25/33; 75,8%) ou divergência (11/16; 68,8%) entre os resultados histopatológicos pré-operatórios e cirúrgicos (p = 0,605). CONCLUSãO: Nossos achados corroboram a literatura e confirmam o sub-estadiamento de amostras endometriais pré-operatórias com base na avaliação histopatológica, especialmente para tumores endometriais de baixo grau. Outros métodos complementares são necessários para um diagnóstico pré-operatório mais preciso a fim de melhorar o planejamento cirúrgico.

Ultrastructure of the Bacteriocytes in the Midgut of the Carpenter ant Camponotus rufipes: Endosymbiont Control by Autophagy.

The carpenter ant Camponotus rufipes has intracellular bacteria in bacteriocytes scattered in the midgut epithelium, which have different amounts of endosymbionts, according to the developmental stages. However, there are no detailed data about the midgut cells in adult workers. The present work aimed to evaluate the morphology and cellular events that coordinate the abundance of endosymbionts in the midgut cells in C. rufipes workers. The midgut epithelium has digestive cells, bacteriocytes, and cells with intermediate morphology. The latter is similar to bacteriocytes, due to the abundance of endosymbionts, and similar to digestive cells, due to their microvilli. The digestive and intermediate cells are rich in autophagosomes and autolysosomes, both with bacteria debris in the lumen. These findings suggest that midgut cells of C. rufipes control the endosymbiont level by the autophagy pathway.

The fungicide iprodione affects midgut cells of non-target honey bee Apis mellifera workers.

The honey bee Apis mellifera is an important pollinator of agricultural crops and natural forests. Honey bee populations have declined over the years, as a result of diseases, pesticides, and management problems. Fungicides are the main pesticides found in pollen grains, which are the major source of protein for bees. The objective of this study was to evaluate the cytotoxic effects of the fungicide iprodione on midgut cells of adult A. mellifera workers. Bees were fed on iprodione (LD50, determined by the manufacturer) for 12 or 24 h, and the midgut was examined using light and transmission electron microscopies. The expression level of the autophagy gene atg1 was assessed in midgut digestive cells. Cells of treated bees had signs of apoptosis: cytoplasmic vacuolization, apical cell protrusions, nuclear fragmentation, and chromatin condensation. Ultrastructural analysis revealed some cells undergoing autophagy and necrosis. Expression of atg1 was similar between treated and control bees, which can be explained by the facts that digestive cells had autolysosomes, whereas ATG-1 is found in the initial phases of autophagy. Iprodione acts by inhibiting the synthesis of glutathione, leading to the generation of reactive oxygen species, which in turn can induce different types of cell death. The results indicate that iprodione must be used with caution because it has side effects on non-target organisms, such as pollinator bees.

A peritrophin mediates the peritrophic matrix permeability in the workers of the bees Melipona quadrifasciata and Apis mellifera.

The permeability of the peritrophic matrix, essential for its function, depends on its chemical composition. The objective was to determine if the permeability of the peritrophic matrix varies along the midgut and in the presence of anti-peritrophin-55 antibody in Melipona quadrifasciata and Apis mellifera bees. The thickness of the peritrophic matrix in both species varies between the anterior and posterior midgut regions in workers. In A. mellifera dextran molecules with 40 kDa cross the peritrophic matrix, whereas those ≥70 kDa are retained in the endoperitrophic space. In M. quadrifasciata the peritrophic matrix permeability was for molecules <40 kDa. Bees fed on anti-peritrophin-55 antibody showed an increase in peritrophic matrix permeability, but survival was not affected. In the bees studied, the peritrophic matrices have morphological differences between midgut regions, but there is no difference in their permeability along the midgut, which is affected by peritrophin 55.

Targeted sequencing identifies novel variants in common and rare MODY genes.

BACKGROUND: Maturity-onset diabetes of the young (MODY) is a form of monogenic diabetes with autosomal dominant inheritance. To date, mutations in 11 genes have been frequently associated with this phenotype. In Brazil, few cohorts have been screened for MODY, all using a candidate gene approach, with a high prevalence of undiagnosed cases (MODY-X). METHODS: We conducted a next-generation sequencing target panel (tNGS) study to investigate, for the first time, a Brazilian cohort of MODY patients with a negative prior genetic analysis. One hundred and two patients were selected, of which 26 had an initial clinical suspicion of MODY-GCK and 76 were non-GCK MODY. RESULTS: After excluding all benign and likely benign variants and variants of uncertain significance, we were able to assign a genetic cause for 12.7% (13/102) of the probands. Three rare MODY subtypes were identified (PDX1/NEUROD1/ABCC8), and eight variants had not been previously described/mapped in genomic databases. Important clinical findings were evidenced in some cases after genetic diagnosis, such as MODY-PDX1/HNF1B. CONCLUSION: A multiloci genetic approach allowed the identification of rare MODY subtypes, reducing the large percentage of MODY-X in Brazilian cases and contributing to a better clinical, therapeutic, and prognostic characterization of these rare phenotypes.

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.

Morphology of the mandibular gland of the ant Paraponera clavata (Hymenoptera: Paraponerinae).

The ant Paraponera clavata (Fabricius, 1775) is the only extant species of Paraponerinae and is widely distributed in Brazilian forests. Aspects of its biology are documented extensively in the literature; however, knowledge of P. clavata internal morphology, specifically of exocrine glands, is restricted to the venom apparatus. The objective of this study was to describe the mandibular gland morphology of P. clavata workers. The mandibular gland is composed of a reservoir connected to a cluster of Type III secretory cells with cytoplasm rich in mitochondria and lipid droplets, similar to that of other ants. Notably, the glandular secretion is rich in protein and has a solid aspect. This is the first morphological description of the mandibular gland of P. clavata. RESEARCH HIGHLIGHTS: This study presents the morphological description of the mandibular gland of Paraponera clavata (Hymenoptera: Paraponerinae). Singular characteristics of the gland are described: the glandular secretion is rich in protein and has a solid aspect.

Spinosad-mediated effects on survival, overall group activity and the midgut of workers of Partamona helleri (Hymenoptera: Apidae).

Populations of stingless bees have declined around the world and pesticides have been indicated as one of the possible causes of this decrease. Spinosad, which is synthesized from the fermentation process produced by the soil actinomycete Saccharopolyspora spinosa, is one of the most used bioinsecticides today. This study aimed to evaluate the possible effects of spinosad (formulation) on survival, general group activity and the processes of autophagy, apoptosis and oxidative stress in two organs (midgut and brain) of workers of Partamona helleri, after 24 h of oral exposure. Workers were orally exposed to different concentrations of spinosad. The concentration (8.16 × 10-3 mg a.i./mL) that led to the mortality of approximately half the number of treated bees was considered LC50 and was used in behavior, histology and immunofluorescence bioassays. The results revealed that bee survival was substantially reduced with increasing spinosad concentrations. The LC50 of the bioinsecticide compromised general group activity, caused morphological alterations in the midgut and intensified the processes of autophagy, apoptosis and oxidative stress in this organ. The brain, on the other hand, did not present significant alterations under the tested conditions. The data obtained demonstrate, therefore, that spinosad negatively affects individual survival, general group activity and the midgut epithelium of P. helleri.

Morphology and Morphometry of the Midgut in the Stingless Bee Friesella schrottkyi (Hymenoptera: Apidae).

Friesella schrottkyi is a small stingless bee (3-mm long) important for agricultural and native forest pollination. This study describes the morphology and morphometry of the midgut in F. schrottkyi forager workers. The F. schrottkyi midgut presents a single-layered epithelium with digestive, regenerative and endocrine cells. The digestive cells are similar along the entire midgut length with a spherical nucleus, apex with long striated border, cytoplasmic granules in the apical region and well-developed basal labyrinth associated with mitochondria, suggesting they are multifunctional, synthesizing digestive enzymes and peritrophic matrix compounds and absorbing nutrients. Regenerative cells are located around the basal region organized in nests with some cells with a spherical nucleus. Phe-Met-Arg-Phe-NH2-amide (FMRFamide) positive endocrine cells are restricted to the posterior midgut region, suggesting a paracrine function in the midgut. This is the first morphological description of the F. schrottkyi midgut contributing to the comprehension of the digestive process of this bee.

Aedes aegypti larvae treated with spinosad produce adults with damaged midgut and reduced fecundity.

The mosquito Aedes aegypti is the main vector of Dengue, Chikungunya, Zika, and yellow fever viruses, which are responsible for high human morbidity and mortality. The fight against these pathogens is mainly based on the control of the insect vector with the use of insecticides. Among insecticides, spinosad bioinsecticide is efficient against A. aegypti larvae and may be an alternative for vector control. Here, we investigate the sublethal effects of spinosad during midgut metamorphosis of A. aegypti females and its cumulative effects on blood acquisition capacity and fecundity in adults. We studied the midgut because it is an important model organ directly related to blood acquisition and digestion. Treatment of larvae with spinosad induced oxidative stress, apoptosis, and damage to the midgut cells at all stages of development and in adults. There was a reduction in the number of proliferating cells and the number of enteroendocrine cells in treated individuals. In addition, damage caused by spinosad led to a reduction in oviposition and egg viability of A. aegypti females. Finally, the exposure of mosquito larvae to sublethal concentrations of spinosad interfered with the development of the midgut, arresting the blood digestion and reproduction of adult females with blood digestion and reproduction difficulties.

Toxicity and cytotoxicity of the insecticide imidacloprid in the midgut of the predatory bug, Podisus nigrispinus.

The selectivity of insecticides on natural enemies in pest control are an important strategy for Integrated Pest Management. However, insecticides can have side effects on non-target organisms such as natural enemies. This study evaluated the histological and cytological changes mediated by the sublethal concentration of the imidacloprid insecticide on the midgut of non-target predator Podisus nigrispinus (Heteroptera: Pentatomidae), used in the biological control of pests. Imidacloprid was toxic for P. nigrispinus with LC50 = 3.75 mg L-1 and survival of 51.8%. This sublethal concentration of imidacloprid causes histological alterations in the midgut epithelium and cytotoxic features were irregular border epithelium, cytoplasmic vacuolation, and apocrine secretions in the first 6 h after exposure with the insecticide. Apoptosis in the digestive cells occurs after 12 h of exposure in the midgut. These results suggest that imidacloprid may affect the digestive physiology of P. nigrispinus and compromise the effective predation of this insect a biological control agent. The associated use of this insecticide with the predator in pest control should be carefully evaluated.

Permethrin induces histological and cytological changes in the midgut of the predatory bug, Podisus nigrispinus.

Insecticides used in the agriculture and forestry have side effects on non-target organisms used as natural enemies. This study evaluated the histopathology and cytotoxicity of permethrin on the midgut of the non-target predatory bug, Podisus nigrispinus (Heteroptera: Pentatomidae) used in the biological control of pest insects. The toxicity and survival of this insect were determined using six concentrations of permethrin via ingestion. Histological and ultraestutural changes of the midgut of P. nigrispinus were analyzed after exposure to permethrin. The insecticide caused toxicity in P. nigrispinus with LC50 = 0.46 µg L-1 and survival of 47% after 72 h of exposure. The histological changes in the midgut were irregularly bordered epithelium, cytoplasmic vacuolization and apocrine secretions in the lumen after 6 h following exposure to the insecticide. Cytotoxic effects such as granules and vacuoles secreted into the lumen, presence of autophagosomes, and dilatation of infolds of the basal plasma membrane were observed in the three regions of the midgut. Cells of the midgut in apoptosis occurred after 12 h of exposure. Permethrin causes toxic effects, inhibits survival, and produces changes in the histology and cytology of the midgut in P. nigrispinus, suggesting that the cell stress induced by this insecticide can disrupt physiological processes such as digestion, compromising the potential of the predator as a biological control agent of pests. The low selectivity of permethrin to a non-target organism such as the predatory bug, P. nigrispinus indicates that the associated use of this insecticide in biological control should be better evaluated.

Toxicological and morphological effects of tebufenozide on Anticarsia gemmatalis (Lepidoptera: Noctuidae) larvae.

The velvetbean caterpillar, Anticarsia gemmatalis Hübner (Lepidoptera: Noctuidae), is an important soybean pest in the Americas. Tebufenozide, a novel nonsteroidal ecdysone agonist is used to control this pest. Bioassays were conducted to assess tebufenozide toxicity and their ultrastructural effects on midgut of A. gemmatalis. The toxicity, survivorship, behavior response, and respiration rate for A. gemmatalis larvae after exposure to tebufenozide were evaluated. Also, A. gemmatalis larvae were treated with LC50 obtained from tebufenozide and changes were observed on their midgut cells after 24, 48 and 96 h. Tebufenozide was toxic to A. gemmatalis (LC50 = 3.86 mg mL-1 and LC90 = 12.16 mg mL-1) and survivorship was 95% for adults that had not been exposed to tebufenozide, decreasing to 52% with LC50 and 27% with LC90 estimated value. Damage to midgut cells was increased with exposure time. These cells show damaged striated border with release of protrusions to the midgut lumen, damaged nuclear membrane and nucleus with condensed chromatin and increase in amount of autophagic vacuoles. Mitochondria were modified into nanotunnels which might be an evidence that tebufenozide induces damage to cells, resulting in cell death, proved by immunofluorescence analyses. This insecticide also caused paralysis movement with change in homeostasis and compromised larval respiration. Thus, sublethal exposure to tebufenozide is sufficient to disturb the ultrastructure of A. gemmatalis midgut, which might compromise insect fitness, confirming tebufenozide a possible controlling insecticide.

Histochemistry, immunohistochemistry and cytochemistry of the anterior midgut region of the stingless bee Melipona quadrifasciata and honey bee Apis mellifera (Hymenoptera: Apidae).

The anterior midgut region of stingless bees is anatomically differentiated with tall and narrow cells, whereas in other social and solitary bees this anatomical gut region is lacking. The objective of the present study was to describe the histochemistry, immunohistochemistry and cytochemistry of the anterior midgut region of the stingless bee Melipona quadrifasciata in comparison with the honey bee Apis mellifera. The anterior midgut region of both species was evaluated for identification of the enzymes ß- galactosidase, glucose-6-phosphatase, acid phosphatase, and alkaline phosphatase, the membrane transporter aquaporin, the hormone FMRF-amide, and lysosomes. Histology of the anterior midgut region showed that this region in M. quadrifasciata workers did not present external folds of the wall, whereas the following midgut wall presented many. In A. mellifera, folds in the midgut wall occur starting from the fore- midgut transition region. Despite these morphological differences, the tests evaluated were similar in both species. ß-galactosidase was not found in the anterior midgut cells. Glucose-6-phosphatase and acid phosphatase occurred in the apical region of the gut epithelium. Alkaline phosphatase occurred in vesicles in apical cytoplasm and in the basal plasma membrane infoldings of the epithelial cells. Aquaporin was found in the basal region of the midgut epithelium and in the associated visceral muscles. FMRF-amide was found only in nerve endings in the anterior midgut region. All cells in the anterior midgut region were rich in lysosomes. These results suggest that in both bee species, although they have anatomically different anterior midgut regions, these regions present high metabolic activity and function in cellular homeostasis, lipid absorption and are under neurohormone control.

Sequential medium with GH and IGF-1 improved in vitro development of bovine preantral follicles enclosed in ovarian tissue.

The growth hormone (GH) and growth insulin-like factor-1 (IGF-1) act directly upon the regulation and growth in the different phases of preantral follicles. Thus, it is necessary to define their sequentiality until the in vitro preovulatory development. Therefore, the study aimed to assess the effects of a sequential medium containing GH and/or IGF-1 in the long-duration in vitro culture of preantral ovarian follicles. Ovarian fragments were cultivated: first half (days 1-7), second half (days 7-14) or during 14 culture days. Treatments were identified as: αMEM+; GH â†’ IGF-1; IGF-1 â†’ GH and GH + IGF-1. The culture was designed in 24-well plates, in an incubator at 37°C and 5% CO2 . The parameters of normality, viability, follicles (primordial/in developing) and follicle diameter were evaluated. In addition, the ultrastructure was confirmed with electron transmission microscopy. The results showed that the culture treated with GH â†’ IGF-1 kept the follicular normality and the viability until the 14th day of culture and increased both in the follicular development until 7th day and in the follicular diameter until 14th day, when compared to the control. The treatments IGF-1 â†’ GH and GH + IGF-1 were not effective in the developing and follicular diameter after 7 days of culture, and also reduced the percentage of viability. It is concluded that the bovine preantral follicles cultured in the sequential medium treated with GH â†’ IGF-1 improved the follicular development until the first half of the culture and kept these parameters with normality, viability and ultrastructure until the second half of the in vitro culture.

Vitellogenin transcytosis in follicular cells of the honeybee Apis mellifera and the wasp Polistes simillimus.

Vitellogenin receptor (VgR) is a low-density lipoprotein receptor responsible for the mediated endocytosis of vitellogenin (Vg) during egg formation in insects. The maturing oocyte is enveloped by a follicular epithelium, which has large intercellular spaces during Vg accumulation (patency). However, Vg has been reported in the cytoplasm of follicular cells, indicating that there may be a transcellular route for its transport. This study verified the presence of VgR in the follicular cells of the ovaries of the honeybee Apis mellifera and the wasp Polistes simillimus in order to evaluate if Vg is transported via transcytosis in these insects. Antibodies specific for vitellogenin receptor (anti-VgR), vitellogenin (anti-Vg), and clathrin (anti-Clt) were used for immunolocalization. The results showed the presence of VgR on the apical and basal plasma membranes of follicular cells of the vitellogenic follicles in both species, indicating that VgR may have been transported from the basal to the apical cell domain, followed by its release into the perivitelline space, evidenced by the presence of apical plasma membrane projections containing VgR. Co-localization proved that Vg bind to VgR and that the transport of this protein is mediated by clathrin. These data suggest that, in these social insects, Vg is transported via clathrin-mediated VgR transcytosis in follicular cells.

Squamocin induce histological and ultrastructural changes in the midgut cells of Anticarsia gemmatalis (Lepidoptera: Noctuidae).

Annonaceous acetogenins (Annona squamosa Linnaeus) comprises of a series of natural products which are extracted from Annonaceae species, squamocin proved to be highly efficient among those agents. Squamocin is mostly referred as a lethal agent for midgut cells of different insects, with toxic effects when tested against larva of some insects. In present study, LC50 and LC90 of squamocin for A. gemmatalis Hübner (Lepidoptera: Noctuidae) were calculated using probit analysis. Morphological changes in midgut cells were analyzed under light, fluorescence and transmission electron microscopes when larvae were treated with LC50 and LC90 of squamocin for 24, 48 and 72 h. Results revealed that the maximum damage to midgut cells was found under LC90 where it showed digestive cells with enlarged basal labyrinth, highly vacuolated cytoplasm, damaged apical surface, cell protrusions to the gut lumen, autophagy and cell death. The midgut goblet cells showed a strong disorganization of their microvilli. Likewise, in insects treated with squamocin, mitochondria were not marked with Mitotracker fluorescent probe, suggesting some molecular damage in these organelles, which was reinforced by decrease in the respiration rate in these insects. These results demonstrate that squamocin has potential to induce enough morphological changes in midgut through epithelial cell damage in A. gemmatalis.