Morphological and immunohistochemical study of the midgut and fat body of Spodoptera frugiperda (J.E. Smith) (Lepidoptera: noctuidae) treated with essential oils of the genus Piper.

Essential oils are a promising alternative to insecticides. We investigated the LD50 of oils extracted from Piper corcovadensis, P. marginatum, and P. arboreum after 48 h topical contact with Spodoptera frugiperda larvae using morphometry, histochemistry and immunohistochemistry of the midgut and fat body. Chromatography revealed that E-caryophyllene was the principal compound common to the Piper species. The essential oils of P. corcovadensis, P. marginatum and P. arboreum caused deleterious changes in the midgut of S. frugiperda larvae. P. corcovadensis oil produced the lowest LD50 and significant histopathological alterations including elongation of the columnar cells, formation of cytoplasmic protrusions, reduction in carbohydrate, increased apoptotic index and decreased cell proliferation. P. arboreum oil caused histopathological alterations similar to P. corcovadensis, but caused the highest rate of cell proliferation and increased regenerative cells, which indicated rapid regeneration of the epithelium. Our findings demonstrated the insecticidal potential of P. corcovadensis for control of S. frugiperda owing to the significant damage it inflicted on S. frugiperda midgut.

Effects of citronella oil (Cymbopogon winterianus Jowitt ex Bor) on Spodoptera frugiperda (J. E. Smith) midgut and fat body.

The armyworm, Spodoptera frugiperda, is the principal pest of corn in Brazil. Control is achieved primarily by synthetic insecticides, which cause problems for the agro-ecosystem. Alternative methods of control are under investigation and citronella (Cymbopogon winterianus) essential oil appears to be a promising agent. We investigated the effects of citronella oil using histological, histochemical and immunohistochemical methods. The midgut of larvae treated with citronella exhibited altered epithelium including cytoplasmic protrusions, columnar cell extrusion, pyknotic nuclei, and increased periodic acid-Schiff positive granules. Regenerative cells in the epithelium of the midgut increased in number, which facilitated subsequent regeneration of this tissue. After exposure to citronella, trophocytes, the principal cell type of the fat body, possessed enlarged vacuoles and mitotic bodies, and contained reduced amounts of glycogen, lipid, and protein. Citronella oil caused morphological changes of the midgut and reduction of stored resources in the fat body, which may adversely affect insect reproduction and survival.

Sublethal Effects of Essential Oils From Eucalyptus staigeriana (Myrtales: Myrtaceae), Ocimum gratissimum (Lamiales: Laminaceae), and Foeniculum vulgare (Apiales: Apiaceae) on the Biology of Spodoptera frugiperda (Lepidoptera: Noctuidae).

Spodoptera frugiperda (Smith 1797) (Lepidoptera: Noctuidae) is a major pest of maize, Zea mays L. Its control is often achieved through repeated applications per season of insecticides, which may lead to adverse effects on the ecosystem. Thus, the study of alternative methods with less environmental impact has expanded to include the use of essential oils. These oils are products of the secondary metabolism in plants, and their insecticidal activity has been widely demonstrated in populations of many pest insects. This study evaluated the insecticidal activities of essential oils from Eucalyptus staigeriana, Ocimum gratissimum, and Foeniculum vulgare on Spodoptera frugiperda. Gas chromatography­mass spectrometry profiles and contact toxicity of these oils as well as their sublethal effects on larvae and reproductive parameters in adults were evaluated. All three oils had sublethal effects on S. frugiperda; however, the oil of O. gratissimum showed the best results at all doses tested. These essential oils may have promise for control of S. frugiperda.

Efeito da enrofloxacina sobre a interação blastocisto endométrio e seu reflexo no desenvolvimento placentário e fetal em ratas / Effect of enrofloxacin on the blastocyst endometrial interactions and their impact on placental and fetal development in rats

Estudos têm mostrado efeitos tóxicos da enrofloxacina em diversos tecidos. Assim, testou-se a hipótese de que a enrofloxacina pode interferir no desenvolvimento placentário e gerar efeitos adversos ao feto. A enrofloxacina (Baytril(r)) foi administrada em ratas, na dose de 5mg/kg, diariamente, IM, durante toda a gestação. As placentas foram analisadas morfologicamente, morfometricamente e imuno-histoquimicamente aos sete, 14 e 21 dias de prenhez. Os resultados mostraram que a enrofloxacina reduziu o número de sítios de implantação, o peso e a área total do disco placentário aos 14 e 21 dias de desenvolvimento, além dos elementos constituintes da placenta. A análise histoquímica não revelou alterações significativas no teor de fibras colágenas, elásticas e reticulares. O teste de Tunel mostrou atividade apoptótica apenas nas placentas com 14 dias de desenvolvimento de ambos os grupos, sendo mais intensa no grupo tratado. Não foi observado nenhum indício de malformação na cabeça, no tronco e nos membros dos neonatos. No entanto, houve uma redução significativa no número e no peso dos neonatos no grupo tratado, porém sem afetar o seu comprimento. Assim, concluiu-se que a enrofloxacina administrada na dosagem de 5mg/kg durante prenhez em ratas interfere no número de embriões implantados e no desenvolvimento placentário. Isto sugere cautela na administração da enrofloxacina durante a gestação, pois a exposição contínua a esse antibiótico pode ter reflexos na redução do número e do peso da prole...

Some studies have shown the toxic effects of enrofloxacin in various tissues. Thus, the hypothesis that enrofloxacin could interfere with placental development and generate adverse effects to the fetus was tested in this study. Enrofloxacin (Baytril(r)) was administered in the dose of 5mg/kg daily, i.m., throughout gestation in rats. The placentas were analyzed morphologically, morphometrically, and immunohistochemically on the 7, 14, and 20th days of pregnancy. The results showed that enrofloxacin reduced the number of implantation sites, weight, and placental disk total area at 14 and 20 days of development, in addition to the element components of the placenta. The histochemical analysis did not reveal significant changes in the content of collagen, reticular, and elastic fibers. The TUNEL test showed apoptosis only in placenta development at 14 days in both groups and more intense in the treated group. Head, trunk, and limb malformations were not observed in the neonates. A significant reduction in the number and weight of neonates were observed in the treated group, however, without affecting their length. Thus, it was concluded that the administration of enrofloxacin, at the dosage of 5 mg/kg during pregnancy in rats, interferes in the number of implanted embryos and placental development. This suggests caution in the administration of enrofloxacin during pregnancy because continuous exposure to this antibiotic may have adverse effects, reducing the number and weight of the offspring...

Bioactivity of Piper hispidinervum (Piperales: Piperaceae) and Syzygium aromaticum (Myrtales: Myrtaceae) oils, with or without formulated Bta on the biology and immunology of Spodoptera frugiperda (Lepidoptera: Noctuidae).

The combination of essential oils and Bacillus thuringiensis Berliner may represent an interesting control strategy. Thus, the study tested the following hypothesis: the combination of long pepper oil (Piper hispidinervum L.) and clove (Syzygium aromaticum L.) oils in two concentrations with Xentari WG (Bta) yields a more effective control of Spodoptera frugiperda (JE Smith) (Lepidoptera: Noctuidae) affecting biological and reproductive parameters and leading to changes in the levels of phenoloxidase and nitric oxide in the hemolymph of the pest. The results demonstrate that only long pepper oil, at the highest concentration with Xentari WG (Bta), promotes reduced larval survival. However, both oils with or without the insecticide interfere in the biology and humoral immunity of S.frugiperda. All treatments caused a decrease in the amount of eggs, except for the clove oil at both concentrations without Bta. Therefore, the use of these oils is a promising alternative for the integrated management of S. frugiperda; however, its association with Bta demonstrated no significant increase in their efficiency.

Efeito da dexametasona e melatonina exógenas sobre parâmetros sanguíneos, progesterona, carboidratos totais e histomorfometria de órgãos em ratas prenhes / The effect of dexamethasone and exogenous melatonin on blood parameters, progesterone, total carbo hydrates and histomorphometry of organs in pregnant rats

A dexametasona é utilizada em casos de gestação com risco de prematuridade; porém, doses suprafisiológicas podem afetar a embriogênese. A melatonina tem demonstrado prevenir efeitos deletérios dos glicocorticoides. Assim, avaliamos a influência da melatonina sobre efeitos da dexametasona em ratas prenhes através dos seguintes parâmetros: 1. Hemograma e perfil glicídico; 2. Níveis de progesterona; e 3. Histomorfometria e histoquímica. Foram utilizadas 20 ratas divididas nos grupos: I - ratas prenhes que receberam placebo (Controle); II - ratas prenhes tratadas com dexametasona (0,8mg/kg); III - ratas prenhes tratadas com melatonina (0,5mg/kg); IV - ratas prenhes tratadas com dexametasona e melatonina. Todos os tratamentos foram iniciados 10 dias após confirmação do acasalamento até o final da prenhez. O sangue foi coletado no 7º, 14º e 21º dia de prenhez. As dosagens de carboidratos e progesterona foram realizadas pelo método antrona e ELISA, respectivamente. O fígado, rins e adrenais foram analisados histoquímica e morfometricamente. No 7º dia de prenhez, não houve alteração significativa nos parâmetros analisados. Porém, no 14º dia de prenhez, houve aumento significativo do volume de hematócrito, redução do número total de hemácias e leucócitos, neutrofilia, linfopenia, eosinopenia e redução do diâmetro das hemácias nas matrizes tratadas com dexametasona. Esses efeitos permaneceram no 21º dia de prenhez, exceto para o hematócrito, o qual reduziu. Verificou-se ainda redução significativa dos níveis de glicose (21º dia de prenhez) e progesterona (14º e 21º dia de prenhez). Não houve alteração nos parâmetros morfométricos e histoquímico no fígado, rins e adrenais. A dexametasona na dosagem de 0,8mg/kg, administrada a partir do terço médio da prenhez, produz alterações hematológicas, bioquímicas e hormonais em ratas, sendo prevenidas pela melatonina; porém não afeta o fígado, rins e adrenais quanto aos parâmetros morfométricos e histoquímicos.

Dexamethasone is used in cases of pregnancy with prematurity risk. However, it may affect the embryogenesis when used in supraphysiological doses. Melatonin has been shown to prevent the deleterious effects of glucocorticoids. Therefore, the influence of melatonin on the effects of dexamethasone on pregnant rats was evaluated through the following parameters: 1. Hemogram and glucose profile; 2. Progesterone levels; 3. Histomorphometry and histochemistry analyses. Twenty female rats were divided into the following groups: I - rats that received placebo (Control); II - rats treated with dexamethasone (0.8mg/kg); III - rats treated with melatonin (0.5mg/kg); IV - rats treated with dexamethasone and melatonin. All treatments started 10 days after confirmation of mating and lasted until the end of the pregnancy. Blood samples were collected on the 7th, 14th, and 21st day. Carbohydrate and progesterone levels were determined with the antrona and ELISA method, respectively. The liver, kidneys, and adrenal glands were analyzed morphometrically and histochemically. On the 7th day of pregnancy there were no significant changes in the parameters analyzed. However, at 14 days of pregnancy there was a significant increase of hematocrit, reducing the total number of erythrocytes and leukocytes, neutrophilia, lymphopenia, eosinopenia and reduced diameter of red blood cells in rats treated with dexamethasone. These effects remained on the 21st of day of pregnancy, except for the hematocrit, which was reduced. There was also a significant reduction in glucose levels (21st day) and progesterone (14th and 21st days). There was no change in the histochemical and morphometric parameters in the liver, kidneys and adrenals. Dexamethasone at a dosage of 0.8mg/kg administered from the middle third of pregnancy produces hematological, biochemical and hormonal changes in rats, being prevented by melatonin, but does not affect the liver...

Fitness costs associated with field-evolved resistance to chlorantraniliprole in Plutella xylostella (Lepidoptera: Plutellidae).

Plutella xylostella (L.) is the most important pest of Brassicaceae worldwide, with a recent estimate of US$ 4-5 billion expenditure for the control of this insect. A case of very high resistance of this pest to chlorantraniliprole was recently associated with reduced efficacy in a Brazilian field of Brassica spp. Although diamide resistance has been characterized, the fitness of insects due to such resistance has yet to be examined. Therefore, in this study, biological parameters were assessed in both susceptible and resistant strains of P. xylostella subjected to sublethal chlorantraniliprole concentrations. The field strain showed high resistance to chlorantraniliprole (RR50=27,793-fold), although resistance rapidly decreased in the first generations, showing instability. The exposure of susceptible and resistant larvae to their respective LC1, LC10, and LC25 values led to an increased duration of the larval and pupae phases and reduced weight in both strains; however, no significant differences in pupal viability across the treatments were observed. The resistant insects presented significantly lower larval weight and fecundity and higher larval and pupal periods, hatchability, and male longevity when not exposed to chlorantraniliprole, suggesting a fitness cost associated with resistance. In addition, resistant females showed a significantly higher egg-laying period and longevity at LC25, whereas the males lived longer at LC1. Chlorantraniliprole negatively impacted the biological parameters of both strains tested, although these effects were more relevant to the resistant insects. Resistant P. xylostella showed negative and positive biological trade-offs when compared with the susceptible individuals in both the absence and presence of chlorantraniliprole. Despite the important role that these trade-offs may play in the evolution of resistance to chlorantraniliprole, practical applications still depend on such information as the dominance of fitness costs and resistance.

Effects of Piper hispidinervum on spermatogenesis and histochemistry of ovarioles of Spodoptera frugiperda.

The fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), not only damages crops, but controlling its population also requires synthetic insecticides, which leads to selection of resistant populations and environmental contamination. Essential oils are an alternative for controlling this insect. There are few studies of the effects of these oils on the insect's reproductive system. We evaluated the effects of the long pepper, Piper hispidinervum, essential oil on the gonads of the armyworm and tested its possible influence on the fertility of this insect. Dosages of 30 and 50 mg/ml were tested in 3(rd) instar caterpillars using the leaf immersion method. Testes and ovarioles were collected, fixed with 10% formalin and embedded in Historesin. The sections were stained with toluidine blue and Mallory trichrome to detect connective tissue, periodic acid-Schiff to detect neutral carbohydrates, and bromophenol blue to detect proteins. We found that the long pepper essential oil affected negatively the spermatogenesis and altered the histochemistry of the ovarioles of S. frugiperda. The effects of long pepper oil suggest that it is a promising tool for controlling the armyworm pest.

Ação da melatonina sobre a dinâmica sanguínea de ratas prenhes e sobre a histogênese do baço e do timo da prole / The action of melatonin on the blood dynamics of pregnant rats and on the histogenesis of the spleen and thymus of offspring

Investigou-se a influência da melatonina sobre o hemograma de ratas prenhes e dos filhotes e sobre a histogênese e morfometria do baço e do timo dos filhotes. A melatonina foi administrada na dose 0,5mg/kg de peso corporal, dissolvida em 0,1mL de etanol e diluída em 0,3mL de solução salina. Para análise do hematócrito, contagem total de hemácias e contagem total e diferencial dos leucócitos, amostras de sangue foram coletadas no sétimo, 14ºe 21ºdias de prenhez e aos 10 dias de nascimento dos filhotes. Cortes histológicos do baço e do timo da prole foram utilizados para histoquímica e morfometria. A ausência da melatonina promoveu alterações no hemograma apenas no terço final da gestação, sem interferir no hemograma dos filhotes, e induziu modificações morfológicas e morfométricas no timo e no baço nos primeiros dias de vida dos filhotes. Concluiu-se que a melatonina materna é importante para a modulação do hemograma em ratas prenhes e para o desenvolvimento normal do baço e do timo dos filhotes.

We investigated the influence of melatonin on the hemogram of pregnant rats and puppies, and on the histogenesis and morphology of the spleen and thymus of puppies. Melatonin was administered at a dose 0.5mg/kgbody weight, dissolved in 0.1mL of ethanol and diluted in 0.3mL of saline. For hematocrit analysis, total erythrocyte count and total and differential leukocyte count, blood samples were collected on the 7th, 14th and 21st days of pregnancy and the offspring at 10 days of birth. Histological sections of spleen and thymus of the offspring were used for histochemistry and morphometry. The absence of melatonin promoted changes in blood count only in the final third of gestation, without interfering with the hemogram of the puppies, and induced morphological and morphometric changes in the thymus and spleen in the first days of life of the puppies. It was concluded that maternal melatonin is important for the modulation of the blood count in pregnant rats and the normal development of the spleen and thymus of the offspring.

Efeito da administração pré-natal da dexametasona em ratas sobre os perfis glicídicos e hematológicos materno e da prole / Effect of prenatal administration of dexamethasone in rats on profiles hematologic and glicidic maternal and offspring

Avaliou-se o efeito da administração de dexametasona no início e no meio da gestação de ratas, sobre os perfis glicídicos e hematológicos materno e da prole. Os animais foram submetidos aos seguintes tratamentos: dexametasona do primeiro ao sétimo dia e placebo do oitavo ao 14º dia; placebo do primeiro ao sétimo dia e dexametasona do oitavo ao 14º dia; dexametasona do primeiro ao 14º dia e placebo do primeiro ao 14º dia de gestação. A dexametasona foi administrada por via intraperitoneal, na dose de 0,8mg/kg. Foram coletadas amostras de sangue no sétimo, 14º e 21º dias de gestação, e de sangue e tecido hepático da prole no quinto, 10º e 15º dias pós-natal. Para a verificação das reservas de glicogênio hepático da prole, cortes histológicos foram corados pelo ácido periódico de Schiff. Os resultados apontam para um efeito tempo-dependente da administração de dexametasona durante a gestação, levando a alterações temporais distintas na hematologia e na concentração plasmática de carboidratos nas matrizes e na prole.

The effect of the administration of dexamethasone at the beginning and middle of the pregnancy in rats on hematological and glicidic maternal and offspring profile was evaluated. The animals underwent the following treatments: dexamethasone from the first to the seventh day and placebo from the 8th to the 14th day, placebo from the first to the seventh day and dexamethasone from the 8th to the 14th day; dexamethasone from the 1st to the 14th day, and placebo treatment from the first to the 14th day of gestation. Dexamethasone was administered intraperitoneally at a dose of 0.8 mg/kg. Blood samples were collected on the 7th, 14th and 21st days of pregnancy, and blood and liver tissue of offspring on the fifth, 10th and 15th days postnatal. For verification of the reserves of liver glycogen on the offspring, histological sections were stained with periodic acid-Schiff. The results point to a time-dependent effect of dexamethasone during pregnancy, leading to different temporal changes in hematology and plasma levels of carbohydrates in headquarters and in the offspring.

Preferência de oviposição e sua relação com o desempenho de Diaphania hyalinata (L, 1758) (Lepidoptera: Crambidae) em cucurbitáceas / Preferência de oviposição e sua relação com o desempenho de Diaphania hyalinata (L, 1758) (Lepidoptera: Crambidae) em cucurbitáceas

Diaphania hyalinata L. (Lepidoptera, Pyralidae) destaca-se como principal praga da família Cucurbitaceae. Este lepidóptero é oligófago de hábito polífago, que desperta largo interesse de estudos da sua ecologia comportamental por motivos de manejo em culturas de grande importância econômica como o meloeiro (Cucumis melo L.). Dada esta situação, trabalhos básicos de entendimento de aspectos da ecologia são necessários para a melhoria das formas de manejo, principalmente no aspecto do monitoramento populacional. Diante disso, a presente pesquisa teve como objetivo verificar se a escolha do hospedeiro exercida por fêmeas de D. hyalinata corresponde ao melhor desempenho da prole e como os hospedeiros influenciam sua dinâmica populacional. Testes de oviposição com chance de escolha foram realizados em melão, melancia, maxixe, bucha, melãode-são-caetano e pepino, para estabelecimento de um ranking de preferência. Para o desempenho das lagartas e reprodução foi escolhido o melão (dentre o mais preferido) e a bucha e o pepino (dentre os hospedeiros menos preferidos). Os resultados suportam a hipótese de que a escolha de hospedeiro é relacionada com o desempenho da prole e que D. hyalinata demonstrou possuir plasticidade ao lidar com diferentes hospedeiros o que pode ser um indicativo de capacidade de adaptação a recursos alimentares que flutuam em termos de qualidade e disponibilidade. No entanto, de modo geral, esta plasticidade tem custos elevados, principalmente em termos reprodutivos.

Diaphania hyalinata L. (Lepidoptera, Pyralidae) stands out as a major pest of the Cucurbitaceae family. This insect is oligophagous with a polyphagous habit, which arouses wide interest in studies of their behavioral ecology for reasons of pest management in crops of high economic importance such as muskmelon (Cucumis melo L.). Given this situation, basic studies aimed at an understanding of ecological aspects of this pest are needed to improve pest management systems, especially in the aspect of population monitoring. Given this, the present study was aimed to determine whether the choice of the host exerted by females of D. hyalinata corresponds to the best performance of the offspring and how the hosts influence their population dynamics. Oviposition-choice tests were performed on melon, watermelon, cucumber, loofah, balsam apple and cucumber, to establish a ranking of preference. For the performance of larvae and reproduction the melon was chosen (among the most preferred hosts) along with loofah and cucumber (among the least preferred hosts). The results support the hypothesis that the choice of host is related to the performance of the offspring and D. hyalinata has demonstrated plasticity in dealing with different hosts which may be indicative of ability to adapt to fluctuating food resources in terms of quality and availability. However, generally this plasticity is expensive, especially in reproductive terms.

Histological description of the midgut and the pyloric valve of Tropidacris collaris (Stoll, 1813) (Orthopetera: Romaleidae)

The present research describes the histology of the midgut, gastric caeca, and pyloric valve of Tropidacris collaris (Stoll, 1813), (Orthopetera: Romaleidae). We used light microscopy, staining (Gomori's trichrome and periodic acid-Schiff (PAS)), and a routine histological analysis method (hematoxilin-eosin). The insects were obtained from, and also bred in, the Laboratory of Entomology, Department of Biology, of the Rural Federal University of Pernambuco (UFRPE). The collected material was fixed in alcoholic Boüin and embedded in paraplast. The results demonstrated that the midgut wall is composed of an inner epithelial layer and two outer layers of striate muscles: one internal (circular) and the other external (longitudinal), with connective tissue between the muscle fibers. The epithelium is single-layered, with two cell types: regenerative and elongated columnar. The gastric caeca presents muscle layers similar to those of the midgut. Simple columnar epithelium lines the gastric caeca, which presents villi and projects towards the lumen. The pyloric valve is of striate muscle tissue, covered by a single epithelial-cell layer.

A presente pesquisa teve como objetivo descrever a histologia do mesêntero, cecos gástricos e válvula pilórica de Tropidacris collaris (Stoll, 1813) (Orthoptera: Romaleidae), por meio da microscopia de luz, utilizando-se colorações especiais (Tricrômico de Gomori e P.A.S. - Acido periódico de Schiff) e de rotina (Hematoxilina-Eosina). Os insetos foram obtidos da criação existente no Laboratório de Entomologia, do Departamento de Biologia, da UFRPE. O material coletado foi fixado em Boüin alcoólico e processado para inclusão em "paralast". Os resultados mostraram que a parede do mesêntero é constituída por duas camadas de músculo estriado: uma interna (circular) e outra externa (longitudinal), com a presença de tecido conjuntivo entre as fibras musculares. O epitélio é do tipo simples, constituído por dois tipos de células: células regenerativas e células colunares altas. Os cecos gástricos também apresentam as camadas de músculo semelhantes às observadas no mesêntero. O tecido epitelial é do tipo simples colunar projetando-se para a luz do órgão, formando vilosidades. A válvula pilórica é constituída por tecido muscular estriado, recoberto por tecido epitelial.

Histological description of the midgut and the pyloric valve of Tropidacris collaris (Stoll, 1813) (Orthopetera: Romaleidae).

The present research describes the histology of the midgut, gastric caeca, and pyloric valve of Tropidacris collaris (Stoll, 1813), (Orthopetera: Romaleidae). We used light microscopy, staining (Gomori's trichrome and periodic acid-Schiff (PAS)), and a routine histological analysis method (hematoxilin-eosin). The insects were obtained from, and also bred in, the Laboratory of Entomology, Department of Biology, of the Rural Federal University of Pernambuco (UFRPE). The collected material was fixed in alcoholic Botüin and embedded in paraplast. The results demonstrated that the midgut wall is composed of an inner epithelial layer and two outer layers of striate muscles: one internal (circular) and the other external (longitudinal), with connective tissue between the muscle fibers. The epithelium is single-layered, with two cell types: regenerative and elongated columnar. The gastric caeca presents muscle layers similar to those of the midgut. Simple columnar epithelium lines the gastric caeca, which presents villi and projects towards the lumen. The pyloric valve is of striate muscle tissue, covered by a single epithelial-cell layer.