Sublethal Effects Induced by a Cyflumetofen Formulation on Honeybee Apis mellifera L. Workers: Assessment of Midgut, Hypopharyngeal Glands, and Fat Body Integrity.

Worldwide, both cultivated and wild plants are pollinated by the honey bee, Apis mellifera. Bee numbers are declining as a result of a variety of factors, including increased pesticide use. Cyflumetofen controls pest mites in some plantations pollinated by bees, which may be contaminated with residual sublethal concentrations of this pesticide, in nectar and pollen. We evaluated the effects of a sublethal concentration of a cyflumetofen formulation on the midgut, hypopharyngeal gland, and fat body of A. mellifera workers orally exposed for 72 h or 10 days. The midgut epithelium of treated bees presented digestive cells with cytoplasm vacuoles and some cell fragmentation, indicating autophagy and cell death. After being exposed to the cyflumetofen formulation for 72 h, the midgut showed a higher injury rate than the control bees, but after 10 days, the organs had recovered. In the hypopharyngeal gland of treated bees, the end apparatus was filled with secretion, suggesting that the acaricide interferes with the secretory regulation of this gland. Histochemical tests revealed differences in the treated bees in both exposure periods in the midgut and hypopharyngeal glands. The acaricide caused cytotoxic effects on the midgut digestive cells, with apical protrusions, plasma membrane rupture, and several vacuoles in the cytoplasm, features of cell degeneration. In the hypopharyngeal glands of the treated bees, the secretory cells presented small electron-dense and large electron-lucent secretory granules. The fat body cells had no changes in comparison with the control bees. In conclusion, the cyflumetofen formulation at sublethal concentrations causes damage to the midgut and the hypopharyngeal glands of honey bee, which may compromise the functions of these organs and colony fitness. Environ Toxicol Chem 2024;43:2455-2465. © 2024 SETAC.

Minthostachys verticillata Griseb (Epling.) (Lamiaceae) essential oil orally administered modulates gastrointestinal immunological and oxidative parameters in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Minthostachys verticillata (Griseb.) Epling (Lamiaceae) is a plant used in folk medicine for digestive or respiratory disorders. In addition, it is incorporated as condiment, in foods, as beverage flavoring or mate. The ethnopharmacological interest of M. verticillata resides in its essential oil (EO). Part of group has demonstrated the immunomodulatory ability of EO giving this oil a biological potential not known until that moment and conducted studies to evaluate their possible application in diseases of veterinary interest. However, the immunomodulatory effects of EO administered orally have not been fully characterized. AIM OF THE STUDY: This study evaluated the impact of EO oral administration on gastrointestinal and immune health through measurement of immunological and oxidative parameters in mice. MATERIAL AND METHODS: The EO was extracted from the leaves, slender stems and flowers of M. verticillata by hydrodistillation and chemical analyzed by gas chromatography-mass spectrometry (GC-MS). Prior to in vivo study, the cytotoxic effect of EO was determined using the human colon carcinoma Caco-2 cell line. For in vivo study, three groups of male Balb/c mice (n = 3) were orally administered with saline solution (control group) and EO (5 or 10 mg/kg/day) during 10 consecutive days. Subsequently, histological and hematological parameters, cytokines production, oxidative markers and CD4+ and CD8+ T cells were evaluated. RESULTS: The chemical analysis of EO revealed the presence of a high content of monoterpenes, being the main pulegone (76.12%) and menthone (14.28%). The EO oral administration improved mice growth performance and modulated systemic adaptive immune response by increasing in the total leukocyte number. A high percentage of CD4+ T cells were observed whereas the number of CD8+ T cells was not altered. EO did not alter the morpho-physiology of intestine and improved total antioxidant capacity by decreasing MDA concentrations. In addition, EO decreased the IL-6 levels and increased in the IL-4 and IL-10 concentrations. CONCLUSION: Results indicate that M. verticillata EO modulate inflammatory and oxidative parameters constituting a natural alternative which could be applied to improve gastrointestinal and immune functionality in animals.

Exposure to copper sulfate impairs survival, post-embryonic midgut development and reproduction in Aedes aegypti.

Aedes aegypti is a vector of several global human viruses responsible for high human morbidity and mortality. The method to prevent the transmission of vector-borne viruses is mainly based on the control of the insect vector using insecticides. Among these chemicals, copper sulfate is a compound widely used in agriculture with the potential to be used as an alternative to control these insects. This study evaluated the effects of the exposure of A. aegypti larvae to copper sulfate on survival, midgut morphology, blood-feeding and fecundity. The exposure to CuSO4 decreased the survival of A. aegypti during the immature phase. Adults obtained from exposed larvae had their lifespan decreased at all tested concentrations. The exposure to CuSO4 impaired the development in the transition from larvae to pupae and from pupae to adult. The number of eggs laid by females developed from larvae treated with CuSO4 was significantly lower than in control. In addition, the egg hatching rates were also negatively affected. The midguts of treated larvae and pupae showed epithelial disorganization. The number of cleaved caspase-3 cells increased in the midgut of exposed pupae compared to control. Moreover, there was a reduction in proliferating cells in treated larvae and pupae compared to the control. In conclusion, the results reveal that CuSO4 exposure has insecticidal activity against A. aegypti, which may be related to the impairment of the midgut metamorphosis and reduced proliferation of stem cells, with the consequent impairment of female mosquito fertility and fecundity.

L-glutamina e zinco em dietas para frangos de corte criados em condições naturais de calor / L-glutamine and zinc in diets for chickens created under natural conditions of heat

Objetivou-se avaliar a suplementação de L-glutamina e zinco em dietas para frangos de corte criados em condições naturais de calor sobre o desempenho produtivo nos períodos de 1 a 7 e de 1 a 21 dias de idade; e o peso dos órgãos digestivos e do coração aos 21 dias de idade. Foram utilizados 630 pintos de corte da linhagem Ross, distribuídos em delineamento inteiramente casualizados em esquema 2 (1 e 2% de L-glutamina) x 3 (0, 90, e 120 mg de zinco/kg de ração) + 1 (dieta controle), totalizando sete tratamentos e cinco repetições com 18 aves cada. A suplementação combinada de L-glutamina e zinco não influenciou as variáveis avaliadas, porém a suplementação isolada de L-glutamina proporcionou maior viabilidade criatória e índice de eficiência produtiva, além de maior peso de fígado e moela dos animais. Da mesma forma, o zinco de forma isolada interferiu de maneira linear decrescente nos pesos relativos do fígado, moela, pâncreas e coração. Concluem-se que dietas suplementadas com1% de L-glutamina melhoram a viabilidade criatória, o índice de eficiência produtiva, o peso de fígado e moela de frangos de corte na fase de 1 a 21 dias de idade, bem como que a adição de zinco interfere no peso dos órgãos digestivos e coração das aves criadas em condições naturais de calor.

The objective of this study was to evaluate the supplementation of L-glutamine and zinc in diets for broilers reared in natural conditions of heat on the productive performance in the periods from 1 to 7 and from 1 to 21 days of age and, weight of digestive organs and heart at 21 days of age. Six hundred and thirty Ross broiler chicks were used, distributed in a completely randomized design, in scheme 2 (1 and 2% L-glutamine) x 3 (0, 90, and 120 mg of zinc/kg of feed) + 1 (diet control), totaling seven treatments and five repetitions, with 18 birds each. The combined supplementation of L-glutamine and zinc did not influence the variables evaluated, however the isolated supplementation of L-glutamine provided greater creative viability and productive efficiency index in addition toa greater weight of liver and gizzard of the animals. Likewise, zinc alone interfered in a linear decreasing manner on the relative weights of the liver, gizzard, pancreas and heart. Diets supplemented with 1% L-glutamine improve the creative viability, the production efficiency index, the weight of liver and gizzards of broilers in the phase from1 to 21 days of age and the addition of zinc interferes in the weight of the digestive organs and heart of birds raised in natural heat.

L-glutamina e zinco em dietas para frangos de corte criados em condições naturais de calor / L-glutamine and zinc in diets for chickens created under natural conditions of heat

Objetivou-se avaliar a suplementação de L-glutamina e zinco em dietas para frangos de corte criados em condições naturais de calor sobre o desempenho produtivo nos períodos de 1 a 7 e de 1 a 21 dias de idade; e o peso dos órgãos digestivos e do coração aos 21 dias de idade. Foram utilizados 630 pintos de corte da linhagem Ross, distribuídos em delineamento inteiramente casualizados em esquema 2 (1 e 2% de L-glutamina) x 3 (0, 90, e 120 mg de zinco/kg de ração) + 1 (dieta controle), totalizando sete tratamentos e cinco repetições com 18 aves cada. A suplementação combinada de L-glutamina e zinco não influenciou as variáveis avaliadas, porém a suplementação isolada de L-glutamina proporcionou maior viabilidade criatória e índice de eficiência produtiva, além de maior peso de fígado e moela dos animais. Da mesma forma, o zinco de forma isolada interferiu de maneira linear decrescente nos pesos relativos do fígado, moela, pâncreas e coração. Concluem-se que dietas suplementadas com1% de L-glutamina melhoram a viabilidade criatória, o índice de eficiência produtiva, o peso de fígado e moela de frangos de corte na fase de 1 a 21 dias de idade, bem como que a adição de zinco interfere no peso dos órgãos digestivos e coração das aves criadas em condições naturais de calor.(AU)

The objective of this study was to evaluate the supplementation of L-glutamine and zinc in diets for broilers reared in natural conditions of heat on the productive performance in the periods from 1 to 7 and from 1 to 21 days of age and, weight of digestive organs and heart at 21 days of age. Six hundred and thirty Ross broiler chicks were used, distributed in a completely randomized design, in scheme 2 (1 and 2% L-glutamine) x 3 (0, 90, and 120 mg of zinc/kg of feed) + 1 (diet control), totaling seven treatments and five repetitions, with 18 birds each. The combined supplementation of L-glutamine and zinc did not influence the variables evaluated, however the isolated supplementation of L-glutamine provided greater creative viability and productive efficiency index in addition toa greater weight of liver and gizzard of the animals. Likewise, zinc alone interfered in a linear decreasing manner on the relative weights of the liver, gizzard, pancreas and heart. Diets supplemented with 1% L-glutamine improve the creative viability, the production efficiency index, the weight of liver and gizzards of broilers in the phase from1 to 21 days of age and the addition of zinc interferes in the weight of the digestive organs and heart of birds raised in natural heat.(AU)

Fungicide pyraclostrobin affects midgut morphophysiology and reduces survival of Brazilian native stingless bee Melipona scutellaris.

Native stingless bees are key pollinators of native flora and important for many crops. However, the loss of natural fragments and exposure to pesticides can hinder the development of colonies and represent a high risk for them. Nevertheless, most studies are conducted with honeybees and there are not many studies on native species, especially in relation to the effects of fungicides on them. Therefore, the objective of this paper is to evaluate the effects of sublethal concentrations of pyraclostrobin, on Melipona scutellaris forager workers. These Brazilian native stingless bees were submitted to continuous oral exposure to three concentrations of pyraclostrobin in sirup: 0.125 ng a.i./µL (P1), 0.025 ng a.i./µL (P2), and 0.005 ng a.i./µL (P3). Histopathological and histochemical parameters of midgut, as well as survival rate were evaluated. All concentrations of fungicide showed an increase in the midgut lesion index and morphological signs of cell death, such as cytoplasmic vacuolizations, presence of atypical nuclei or pyknotic nuclei. Histochemical analyzes revealed a decreased marking of polysaccharides and neutral glycoconjugates both in the villi and in peritrophic membrane in all exposed-groups in relation to control-groups. P1 and P2 groups presented a reduction in total protein marking in digestive cells in relation to control groups. As a consequence of alteration in the midgut, all groups exposed to fungicide showed a reduced survival rate. These findings demonstrate that sublethal concentrations of pyraclostrobin can lead to significant adverse effects in stingless bees. These effects on social native bees indicate the need for reassessment of the safety of fungicides to bees.

2-Aminoethyldiphenyl Borinate: A Multitarget Compound with Potential as a Drug Precursor.

BACKGROUND: Boron is considered a trace element that induces various effects in systems of the human body. However, each boron-containing compound exerts different effects. OBJECTIVE: To review the effects of 2-Aminoethyldiphenyl borinate (2-APB), an organoboron compound, on the human body, but also, its effects in animal models of human disease. METHODS: In this review, the information to showcase the expansion of these reported effects through interactions with several ion channels and other receptors has been reported. These effects are relevant in the biomedical and chemical fields due to the application of the reported data in developing therapeutic tools to modulate the functions of the immune, cardiovascular, gastrointestinal and nervous systems. RESULTS: Accordingly, 2-APB acts as a modulator of adaptive and innate immunity, including the production of cytokines and the migration of leukocytes. Additionally, reports show that 2-APB exerts effects on neurons, smooth muscle cells and cardiomyocytes, and it provides a cytoprotective effect by the modulation and attenuation of reactive oxygen species. CONCLUSION: The molecular pharmacology of 2-APB supports both its potential to act as a drug and the desirable inclusion of its moieties in new drug development. Research evaluating its efficacy in treating pain and specific maladies, such as immune, cardiovascular, gastrointestinal and neurodegenerative disorders, is scarce but interesting.

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.

Differential responses in the biotransformation systems of the oyster Crassostrea gasar (Adanson, 1757) elicited by pyrene and fluorene: molecular, biochemical and histological approach - Part I.

Polycyclic aromatic hydrocarbons (PAHs) are among the main contaminants in aquatic environments. PAHs can affect organisms due to their carcinogenic, mutagenic and/or teratogenic characteristics. Depending on the PAHs, concentration, and period of exposure, biological damage can occur leading to histopathologic alterations. This study aimed to evaluate the molecular, biochemical and histological responses of the oyster Crassostrea gasar exposed to pyrene (0.25 and 0.5 µM) and fluorene (0.6 and 1.2 µM), after exposure for 24 and 96 h. Concentrations of both PAHs were quantified in the water and in oyster tissues. Transcript levels of phase I (CYP3475C1, CYP2-like, CYP2AU1 and CYP356A) and phase II (GSTO-like, MGST-like and SULT-like) biotransformation-related genes and the activities of ethoxyresorufin-O-deethylase (EROD), total and microsomal glutathione S-transferase (GST and MGST) were evaluated in the gills. Also, histological changes and localization of mRNA transcripts CYP2AU1 in gills, mantle, and digestive diverticula were evaluated. Both PAHs accumulated in oyster tissues. Pyrene half-life in water was significantly lower than fluorene. Transcript levels of all genes were higher in oysters exposed to of pyrene 0.5 µM (24 h). Only CYP2AU1 gene was up-regulated by fluorene exposure. EROD and MGST activities were higher in oysters exposed to pyrene. Tubular atrophy in the digestive diverticula and an increased number of mucous cells in the mantle were observed in oysters exposed to pyrene. CYP2AU1 transcripts were observed in different tissues of pyrene-exposed oysters. A significant correlation was observed between tubular atrophy and the CYP2AU1 hybridization signal in oysters exposed to pyrene, suggesting the sensibility of the species to this PAH. These results suggest an important role of biotransformation-related genes and enzymes and tissue alterations associated to pyrene metabolism but not fluorene. In addition, it reinforces the role of CYP2AU1 gene in the biotransformation process of PAHs in the gills of C. gasar.

Marine contamination and cytogenotoxic effects of fluoxetine in the tropical brown mussel Perna perna.

Concerns are growing about the presence of fluoxetine (FLX) in environmental matrices, as well as its harmful effects on non-target organisms. FLX in aquatic ecosystems has been detected in a range varying from pg/L to ng/L, while adverse effects have been reported in several organisms inhabiting freshwater and marine environments. The present study quantifies FLX concentrations in seawater samples from Santos Bay, Brazil and assesses metabolic responses and sublethal effects on the tropical brown mussel Perna perna. Levels of ethoxyresorufin­O­deethylase, dibenzylfluorescein dealkylase, glutathione S-transferase, glutathione peroxidase, cholinesterase, lipoperoxidation, and DNA damage were assessed in the gills and digestive gland of these animals, and lysosomal membrane stability was also assessed in hemocytes. FLX altered phase I and II enzyme activities, caused cytogenotoxic effects, and negatively impacted the overall health of mussels exposed to environmentally relevant concentrations. These findings contribute to characterize the risks of introducing this drug into the marine environment.

Insect midgut structures and molecules as targets of plant-derived protease inhibitors and lectins.

The midgut of insects is involved in digestion, osmoregulation and immunity. Although several defensive strategies are present in this organ, its organization and function may be disturbed by some insecticidal agents, including bioactive proteins like lectins and protease inhibitors (PIs) from plants. PIs interfere with digestion, leading to poor nutrient absorption and decreasing amino acid bioavailability. Intake of PIs can delay development, cause deformities and reduce fertility. Ingestion of PIs may lead to changes in the set of proteases secreted in the insect gut, but this response is often insufficient and results in aggravation of the malnutrition status. Lectins are proteins that are able to interact with glycoconjugates, including those linked to cell surfaces. Their effects on the midgut include disruption of the peritrophic matrix, brush border and secretory cell layer; induction of apoptosis and oxidative stress; interference with nutrient absorption and transport proteins; and damaging effects on symbionts. In addition, lectins can cross the intestinal barrier and reach the hemolymph. The establishment of resistant insect populations due to selective pressure resulting from massive use of a bioactive protein is an actual possibility, but this can be minimized by the multiple mode-of-action of these proteins, mainly the lectins. © 2018 Society of Chemical Industry.

Binding targets of termiticidal lectins from the bark and leaf of Myracrodruon urundeuva in the gut of Nasutitermes corniger workers.

BACKGROUND: Lectins, carbohydrate-binding proteins, from the bark (MuBL) and leaf (MuLL) of Myracrodruon urundeuva are termiticidal agents against Nasutitermes corniger workers and have been shown to induce oxidative stress and cell death in the midgut of these insects. In this study, we investigated the binding targets of MuBL and MuLL in the gut of N. corniger workers by determining the effects of these lectins on the activity of digestive enzymes. In addition, we used mass spectrometry to identify peptides from gut proteins that adsorbed to MuBL-Sepharose and MuLL-Sepharose columns. RESULTS: Exoglucanase activity was neutralized in the presence of MuBL and stimulated by MuLL. α-l-Arabinofuranosidase activity was not affected by MuBL but was inhibited by MuLL. Both lectins stimulated α-amylase activity and inhibited protease and trypsin-like activities. Peptides with homology to apolipophorin, trypsin-like enzyme, and ABC transporter substrate-binding protein were detected from proteins that adsorbed to MuBL-Sepharose, while peptides from proteins that bound to MuLL-Sepharose shared homology with apolipophorin. CONCLUSION: This study revealed that digestive enzymes and transport proteins found in worker guts can be recognized by MuBL and MuLL. Thus, the mechanism of their termiticidal activity may involve changes in the digestion and absorption of nutrients. © 2018 Society of Chemical Industry.

Spinosad-mediated effects on the walking ability, midgut, and Malpighian tubules of Africanized honey bee workers.

BACKGROUND: The global decline in Apis mellifera colonies is attributed to multiple factors, including pesticides. The bioinsecticide spinosad was initially recognized as safe for non-target organisms; however, its toxicity has been changing this view. Here, we investigated the survival, behavioral changes, and structural changes in the midgut and Malpighian tubules of A. mellifera treated orally with a spinosad formulation. RESULTS: The field-recommended concentration of spinosad killed 100% of the bees. The 5% and 50% lethal concentrations (LC5 and LC50 , respectively) of spinosad altered the behavioral activity, reducing the walking distance and velocity, and increased the resting time in comparison to the control. The LC50 caused disorganization of the epithelia of tested organs and induced oxidative stress and cell death. CONCLUSIONS: The present work provides new insights into the debate about the role of bioinsecticides in the mortality of Africanized honey bees. Even at very low concentrations, the spinosad formulation was toxic to the vital organs midgut and Malpighian tubules and adversely affected walking behavior. This detailed evaluation of the impact of the bioinsecticide on A. mellifera will contribute to the clarification of disturbances probably caused by spinosad formulations, which can be used to develop more sustainable protocols in agriculture. © 2017 Society of Chemical Industry.

Sublethal dose of deltamethrin damage the midgut cells of the mayfly Callibaetis radiatus (Ephemeroptera: Baetidae).

In insects, the midgut performs multiple physiologic functions (e.g., digestion and nutrients absorption) and serves as a physical/chemical barrier against pathogens and chemical stressors such as deltamethrin, a pyrethroid insecticide, commonly used in insect control that are agricultural pests and human disease vectors. Here, we described the midgut cell ultrastructure of Callibaetis radiatus nymphs, which are bioindicators of water quality and the ultrastructural alterations in midgut under sublethal exposure to deltamethrin at three different periods (1, 12, 24 h). The digestive cells of deltamethrin-unexposed nymphs had long microvilli, many mitochondria in the apical cytoplasm, a rough endoplasmic reticulum, a basal labyrinth with openings for hemocele, and the midgut peritrophic matrix which is classified as type I. Nymphs exposed to deltamethrin exhibited digestive cells rich in autophagic vacuoles, basal labyrinth loss, and microvilli disorganization since the first hour of contact with deltamethrin. However, these midgut tissues underwent to autophagic cellular recovery along the 24 h of exposure to deltamethrin. Thus, the sublethal exposure to deltamethrin is sufficient to disturb the ultrastructure of C. radiatus midgut, which might reduce the abilities of these insects to survive in aquatic environments contaminated by pyrethroids.

Thiamethoxam and picoxystrobin reduce the survival and overload the hepato-nephrocitic system of the Africanized honeybee.

Apis mellifera perform important pollination roles in agroecosystems. However, there is often intensive use of systemic pesticides in crops, which can be carried to the colony by forage bees through the collection of contaminated pollen and nectar. Inside the colony, pollen loads are stored by bees that add honey and several enzymes to this pollen. Nevertheless, intra-colonial chronic exposure could induce sublethal effects in young bees exposed to a wide range of pesticides present in these pollen loads. This study was aimed to both determine the survival rate and evaluate the sublethal effects on the hepato-nephrocitic system in response to continuous oral exposure to lower concentrations of neonicotinoid thiamethoxam (TXT) and picoxystrobin fungicide (PXT). Exposure to a single chemical and co-exposure to both pesticides were performed in newly emerged honeybee workers. A significant decrease in the bee survival rates was observed following exposure to TXT (0.001 ng a.i./µL) and PXT (0.018 ng a.i./µL), as well as following co-exposure to TXT+PXT/2. After five days of continuous exposure, TXT induced sub-lethal effects in the organs involved in the detoxification of xenobiotics, such as the fat body and pericardial cells, and it also induced a significant increase in the hemocyte number. Thus, the hepato-nephrocitic system (HNS) reached the greatest level of activity of pericardial cells as an attempt to eliminate this toxic compound from hemolymph. The HNS was activated at low levels by PXT without an increase in the hemocyte number; however, the mobilization of neutral glycoconjugates from the trophocytes of the fat body was prominent only in this group. TXT and PXT co-exposure induced intermediary morphological effects in trophocytes and pericardial cells, but oenocytes from the fat body presented with atypical cytoplasm granulation only in this group. These data showed that the realistic concentrations of these pesticides are harmful to newly emerged Africanized honeybees, indicating that intra-colonial chronic exposure drastically reduces the longevity of bees exposed to neonicotinoid insecticide (TXT) and the fungicide strobilurin (PXT) as in single and co-exposure. Additionally, the sublethal effects observed in the organs constituting the HNS suggest that the activation of this system, even during exposure to low concentrations of theses pesticides, is an attempt to maintain homeostasis of the bees. These data together are alarming because these pesticides can affect the performance of the entire colony.

Receptor mediated endocytosis of vicilin in Callosobruchus maculatus (Coleoptera: Chrysomelidae) larval midgut epithelial cells.

The transport of proteins across the intestinal epithelium of insects is still not well understood. There is evidence that vicilin, a major storage protein of cowpea seeds (Vigna unguiculata), is internalized in larvae of the seed-beetle Callosobruchus maculatus. It has been reported that this vicilin interacts with proteins present in the microvillar membranes of columnar cells along the digestive tract of the larvae. In the present work, we studied the cellular pathway involved in endocytosis of vicilin in larval C. maculatus by employing ex vivo experiments. In the ex vivo approach, we incubated FITC-labelled vicilin with isolated midgut wholemounts in the absence or in the presence of endocytosis inhibitors. The fate of labelled or non-labelled globulins was monitored by confocal microscopy and fluorescence measurement. Our results suggest that the internalization of vicilins is due to receptor-mediated endocytosis. Here we report the identity of a microvillar vicilin-binding protein that was purified using affinity chromatography on a vicilin-sepharose column. The putative vicilin receptor showed high homology to proteins with the CRAL-TRIO domain, specifically the Sec14 superfamily member α-tocopherol transfer protein. The precise mechanism involved in vicilin internalization was defined through the use of specific inhibitors of the endocytosis pathway. The inhibitors filipin III and nystatin significantly inhibited the endocytosis of vicilin, while chlorpromazine and phenylarsine oxide had a much lower effect on endocytosis, suggesting that the endocytic pathway is predominantly mediated by caveolin.

Lufenuron impact upon Anthonomus grandis Boheman (Coleoptera: Curculionidae) midgut and its reflection in gametogenesis.

The insecticide Match® (lufenuron), one of the main insect growth regulators used in pest control, has been presented as a viable alternative against the boll weevil, Anthonomus grandis (Coleoptera: Curculionidae), by inhibiting chitin synthesis. Thus, this study aimed to examine whether Match® interferes in the synthesis of the peritrophic matrix, leading to changes in the midgut epithelium, resulting in nutritional deficiency and reflecting, thereby, in the gametogenesis process of A. grandis. Floral cotton buds were immersed in the insecticide solution (800µL of Match®+200mL of distilled water) and offered to the adult insects. The midguts of the insects were evaluated after 24 and 120h after feeding. The gonads were evaluated after 120h. The results showed that Match®, in both evaluation periods, induced histopathological alterations such as disorganization, vacuolization and desquamation of the midgut epithelium; histochemical modifications in the distribution patterns of carbohydrates, although without quantitative changes; and a strong decrease in protein levels. No apoptosis were observed, however, there was an increase in the number of regenerative cell nests. In the testicles, a reduction in the amount of spermatozoids and reduced carbohydrate levels were observed, but no difference in protein levels. The ovarioles presented structural disorganization of follicular cells, yolk reduction and decrease in protein levels, however, no change in carbohydrates levels was noted. Therefore, it is concluded that Match® performs histopathologic and histochemical alterations in the midgut epithelium and the gonads of A. grandis adults, reflecting in the gametogenesis process, presenting itself as a promising tool in the management of this pest on cotton crops.

Is Selective Digestive Decontamination Useful for Critically Ill Patients?

In this study we review the rationale for using selective digestive decontamination (SDD) in critically ill patients, and its effects on clinical outcomes and rates of infection with antimicrobial-resistant microorganisms. SDD consists of the application of nonabsorbable antibiotics to the oropharynx and through a nasogastric or nasoenteral tube, in association with a 4-day course of an intravenous third-generation cephalosporin. The enteral component aims at preventing oral and rectal colonization with potentially pathogenic nosocomial aerobic gram-negative bacilli and yeasts while preserving normal protective anaerobic enteral flora. The short-course systemic component aims at eradicating oral endogenous gram-positive bacteria. SDD decreases the risk of nosocomial infections, and reduces by one-quarter the mortality of patients on mechanical ventilation in settings with low prevalence of antibiotic resistance. Evidence from randomized trials suggests that SDD does not increase rates of antimicrobial-resistant microorganisms, and may reduce resistance rates to some antibiotics. However, several limitations decrease our confidence on these data, particularly for settings with high baseline rates of antimicrobial-resistant microorganisms. Although SDD has a clear potential to improve clinical outcomes of critically patients, its long-term ecologic effects on rates of antimicrobial resistant require appropriate assessment by large multinational cluster randomized trials. Before these results are available, the use of SDD cannot be recommended in most parts of the world, except in settings with very low baseline prevalence of antibiotic resistance.

Multiple Modes of Action of the Squamocin in the Midgut Cells of Aedes aegypti Larvae.

Annonaceous acetogenins are botanical compounds with good potential for use as insecticides. In the vector, Aedes aegypti (L.) (Diptera: Culicidae), squamocin (acetogenin) has been reported to be a larvicide and cytotoxic, but the modes of action of this molecule are still poorly understood. This study evaluated the changes in the cell morphology, and in the expression of genes, for autophagy (Atg1 and Atg8), for membrane ion transporter V-ATPase, and for water channel aquaporin-4 (Aqp4) in the midgut of A. aegypti larvae exposed to squamocin from Annona mucosa Jacq. (Annonaceae). Squamocin showed cytotoxic action with changes in the midgut epithelium and digestive cells of A. aegypti larvae, increase in the expression for autophagy gene Atg1 and Atg8, decrease in the expression of V-ATPase, decrease in the expression of Aqp4 gene in LC20 and inhibition of Apq4 genes in the midgut of this vector in LC50. These multiple modes of action for squamocin are described for the first time in insects, and they are important because different sites of action of squamocin from A. mucosa may reduce the possibility of resistance of A. aegypti to this molecule.

Histopathological assessment and inflammatory response in the digestive gland of marine mussel Mytilus galloprovincialis exposed to cadmium-based quantum dots.

Although tissue-level biomarkers have been widely applied in environmental toxicology studies, the knowledge using this approach in marine invertebrates exposed to engineered nanomaterials (ENMs) remains limited. This study investigated histopathological alterations and inflammatory responses induced by Cd-based quantum dots (QDs), in comparison with their dissolved counterparts, in the marine mussel Mytilus galloprovincialis. Mussels were exposed to CdTe QDs and dissolved Cd at the same concentration (10µg Cd L(-1)) for 14days and a total of 15 histopathological alterations and 17 histomorphometric parameters were analysed in the digestive gland along with the determination of histopathological condition indices (Ih). A multivariate analysis showed that the mussel response to QDs was more related to exposure time, inflammatory conditions (frequency of haemocytic infiltration and granulocytomas) and changes of cell-type composition (especially the rate between basophilic and digestive cells) when compared to dissolved Cd, while the response to dissolved Cd was associated with histomorphometric parameters of the epithelium and lumen of digestive tubules and increase of the atrophic tubule frequency. Both Cd forms induced higher Ih compared to unexposed mussels indicating a significant decrease in the health status of digestive gland in a Cd form and time-dependent pattern. Results indicate that the multiparametric tissue-level biomarkers in the digestive gland provide a suitable approach to assess the ecotoxicity and mode of action of metal-based ENMs in marine bivalves.