Valéria Wanderley Teixeira

Spermatogenesis, changes in reproductive structures, and time constraint associated with insemination in Podisus nigrispinus.

Males of the predatory stinkbug, Podisus nigrispinus (Dallas) (Hemiptera: Pentatomidae), accomplish long and multiple matings. We hypothesize that this behavior is due to time requirement for spermatozoa production and their transference to the females. Thus, this work investigated the effect of mating status of males and mating duration on spermatozoa transference to the females and the location of spermatozoa in the male reproductive tract during mating. On females, morphological alterations on female spermatheca and associated structures during a mating were investigated. Analyses of male reproductive tract showed presence of spermatozoa in the lumen of vas deferens was independent of mating status (ca. virgin, 0, 12 and 24 h after having a full mating), indicating continuous spermatogenesis which is supported by the absence of a seminal vesicle for spermatozoa storage. Female spermatheca had no changes associated with the duration of mating. However, females exhibited spermathecal elastic duct swelling by 30 min of mating duration. The success of males in filling the female spermatheca with spermatozoa depends on duration of mating. Thus, the results indicate that multiple mating is a requirement for reproductive success in the species by transference of spermatozoa and accessory substances stored in the female spermathecal duct. Likewise, the long mating is a male requirement to transfer materials in appropriate amount to the female but it is not dependent on spermatozoa alone.

Ultrastructural aspects of melatonin cytotoxicity on Caco-2 cells in vitro

Colon adenocarcinoma is a disease expanding worldwide. Cancer of colon and rectum are among the top ten most insidious types in Brazil. In vitro and in vivo studies have demonstrated the efficacy of the hormone melatonin to prevent and reduce tumor growth. However, there are only few studies addressing the action of melatonin on Caco-2 cells. Thus, the cytotoxic effect of melatonin on the ultrastructure of Caco-2 cells was investigated. The MTT colorimetric method was used to assess the cytotoxicity. A total of 2×10(6)cells/mL were seeded in microplates and incubated at 50, 25, 12.5, 6.25, 3.125, 1.56, 0.78 and 0.0 (control) μg/mL of melatonin. For ultrastructural analysis concentrations with low, medium and high cytotoxicity plus the control were used for ultrastructural analysis. The concentrations 50, 1.56 and 0.78 μg/mL of melatonin showed low, medium and high cytotoxicity, respectively. Ultrastructurally, the control tumor cells were shown to be preserved. Caco-2 cells showed morphological changes at 50 μg/mL of melatonin, with numerous vacuoles, mitochondrial degeneration and reduced glycogen. However, Caco-2 cells also showed altered morphology in treatments at 1.56 and 0.78 μg/mL of melatonin with characteristics of cells in degeneration by the presence of numerous vacuoles, absence of microvilli, mitochondrial degeneration and nuclear fragmentation. Thus, one can infer that concentrations of 1.56 and 0.78 μg/mL of melatonin promote cytotoxicity in Caco-2 cells, which can probably be related to the generation of reactive oxygen species (ROS).

Effects of melatonin and prolactin in reproduction: review of literature

The pineal gland is responsible for producing a hormone called melatonin (MEL), and is accepted as the gland that regulates reproduction in mammals. Prolactin (PRL) also exhibits reproductive activity in animals in response to photoperiod. It is known that the concentrations of PRL are high in the summer and reduced during winter, the opposite of what is seen with melatonin in these seasons. In placental mammals, both prolactin and melatonin affect implantation, which is considered a critical point of pregnancy, since a successful pregnancy requires the development of a synchronous interaction between the endometrium and blastocyst for placental development. It is also known that PRL levels during pregnancy are essential for the maintenance of pregnancy, because this hormone induces the corpus luteum to produce progesterone, in addition to stimulating blastocyst implantation to maintain pregnancy and form the placenta. However, melatonin levels in plasma have also been shown to increase during pregnancy, peaking at the end of this period, which suggests that this hormone plays an important role in the maintenance of pregnancy. Thus, it is clear that treatment with prolactin or melatonin interferes with the processes responsible for the development and maintenance of pregnancy.

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.

Histopathology of Organs from Neonate Offspring Born to Female Rats Exposed to Sublethal Doses of Biological and Synthetic Insecticides

El consumo anual actual de insecticidas en la agricultura en Brasil es mas de tres millones de toneladas. Aproximadamente el 60% de los trabajadores rurales expuestos a los insecticidas son mujeres. La exposicion ocurre a traves de alimentos contaminados con desechos toxicos y la absorcion respiratoria y dermica. El control biologico con Bacillus thuringiensis Berliner (Bt) ha adquirido una importancia creciente en la sustitucion del uso de insecticidas convencionales. Sin embargo, las pruebas utilizadas para justificar la aprobacion para el uso y la liberacion del mercado de los productos Bt, y los protocolos utilizados para evaluar el desarrollo de toxicidad, son muy superficiales. Ademas, no se han realizado estudios que que permitan comparar los efectos entre hombres y mujeres y durante el embarazo y la lactancia. Por lo tanto, la hipotesis planteada en este estudio fue si la administracion del Grupo de Trabajo XenTari ® (B. thuringiensis subsp. Aizawai) insecticida biologico y Decis ® 25CE (deltametrina) insecticidas sinteticos, en concentraciones que no causan signos clinicos de toxicidad materna, podria interferir en la histofisiologia de los organos de las ratas recien nacidas. Treinta y cinco ratas albinas prenadas, Rattus norvegicus albino, fueron distribuidas aleatoriamente en siete grupos: Grupo I recibio un placebo (agua), los Grupos II, III y IV recibieron 1,0, 10,0 y 20,0 mg de XenTari ® / kg, respectivamente, y Grupos V, VI y VII recibieron 1,0, 2,0 y 4,0 mg de deltametrina / kg, respectivamente. Los resultados mostraron que las dosis mas altas de insecticidas redujeron el numero de neonatos. No se observaron alteraciones histopatologicas en los rinones, sin embargo, se observaron en el higado, lipidosis, difusas celulas inflamatorias mononucleares, y la congestion de sinusoides. Las ratas de los grupos IV y VII presentaron atresia ovarica. Los recien nacidos de grupo IV mostraron congestion y deposito de hemosiderina en los vasos sanguineos del testiculo, lo cual es caracteristico de un proceso de hemolisis. En conclusion, los insecticidas presentaron efectos similares en los organos y en el numero de recien nacidos de ratas expuestas a dosis sub-letales, que no causan sintomas clinicos de toxicidad materna.

Morphological Analysis of Neonates of Rats Treated with Dexamethasone in the Initial Phase of Pregnancy

SUMMARY: The glucocorticoid dexamethasone has been largely used due to its anti-inflammatory effect. However, severalauthors report that the excessive exposition to it during pregnancy may cause a retard in the development in several tissues, mainly: liver,lungs and kidneys. But, the majority of the works are done with the application of dexamethasone in the late periods of pregnancy.Because of the lack of researches that evaluate the effects in the beginning of gestation, this paper aimed at evaluating the effect ofdexamethasone administered in the initial phase of pregnancy, over the morphology of neonates rat. It was used 10 albino rats (Rattusnorvegicus albinus) aged 90 days from the lineage Wistar. The female were coupled and divided in two groups: Group I – rats notsubmitted to the dexamethasone application (control); Group II – rats submitted to the dexamethasone application in the first 5 days ofpregnancy. The results show that the treatment with dexamethasone in a dosage of 0.8mg/Kg during the 5 first days of pregnancy does notproduces a weight and height reduction or malformation in the offspring, it does not cause changes in the development of the liver andkidneys of neonate rats, but it leads to a reduction in the denseness of the interalveolar septa causing a higher distension of the alveoli.

Effect of the Treatment with Dexamethasone, for 10 and 15 Days, on the Fertility in Induced Rats to Polycystic Ovaries, by Constant Illumination

El estudio tuvo el objetivo de obtener informaciones sobre la fertilidad en ratas tratadas con dexametasona por 10 y 15 dias seguidos, para ovarios poliquisticos, inducidos por iluminacion constante. Se utilizo 40 ratas albinas (Rattus norvegicus albinus) con 90 dias de edad, del linaje Wistar, las cuales fueron divididas, en cuatro grupos, cada uno constituido por 10 animales: Grupo I - ratas mantenidas en ciclo claro/oscuro de 12/12 horas, y despues de 100 dias sometidas a la evaluacion de la fertilidad (control); Grupo II- ratas mantenidas bajo iluminacion constante, durante 100 dias, y luego sometidas a la evaluacion de la fertilidad ; Grupo III - ratas mantenidas bajo iluminacion constante, a lo largo de 100 dias, y posteriormente tratadas con dexametasona por diez dias, y sometidas a la evolucion de la fertilidad; Grupo IV - ratas mantenidas bajo iluminacion constante, durante 100 dias, en seguida tratadas con dexametasona por 15 dias, y sometidas a la evaluacion de la fertilidad. Los resultados mostraron que el numero de sitios implantados fue 38(GI), 37(G2), 32(G3), y 06(G4). La reduccion en el grupo IV fue como consecuencia de la alta mortalidad durante la experiencia, probablemente en funcion del largo tratamiento con dexametasona. Esos sitios presentaron aspectos histologicos semejantes. El analisis macroscopico de los neonatos no mostro ningun vestigio de malformacion. Tampoco fueron observados abortos. El tratamiento con dexametasona por 10 dias en ratas, no afecta la fertilidad y el desarrollo de los pulmones, higado y rinones de neonatos, mientras que la administracion por 15 dias lleva a una alta mortalidad materna.

Bone marrow-derived monocyte infusion improves hepatic fibrosis by decreasing osteopontin, TGF-β1, IL-13 and oxidative stress

AIM To evaluate the therapeutic effects of bone marrow-derived CD11b+CD14+ monocytes in a murine model of chronic liver damage. METHODS Chronic liver damage was induced in C57BL/6 mice by administration of carbon tetrachloride and ethanol for 6 mo. Bone marrow-derived monocytes isolated by immunomagnetic separation were used for therapy. The cell transplantation effects were evaluated by morphometry, biochemical assessment, immunohistochemistry and enzyme-linked immunosorbent assay. RESULTS CD11b+CD14+ monocyte therapy significantly reduced liver fibrosis and increased hepatic glutathione levels. Levels of pro-inflammatory cytokines, including tumor necrosis factor-α, interleukin (IL)-6 and IL-1β, in addition to pro-fibrotic factors, such as IL-13, transforming growth factor-β1 and tissue inhibitor of metalloproteinase-1 also decreased, while IL-10 and matrix metalloproteinase-9 increased in the monocyte-treated group. CD11b+CD14+ monocyte transplantation caused significant changes in the hepatic expression of α-smooth muscle actin and osteopontin. CONCLUSION Monocyte therapy is capable of bringing about improvement of liver fibrosis by reducing oxidative stress and inflammation, as well as increasing anti-fibrogenic factors.

Histological and Histochemical Changes by Clove Essential Oil Upon the Gonads of Spodoptera frugiperda (JE Smith) (Lepidoptera: Noctuidae)

Spodoptera frugiperda es un insecto polifago que causa perdidas economicas a varias cosechas en Brasil y es el mayor obstaculo para la produccion de maiz. Este estudio esta centrado en el control alternativo, con productos botanicos que se estan expandiendo y ofrecen una amplia variedad de moleculas que interfieren con diferentes parametros biologicos de plagas de insectos. Por tanto, se puso a prueba la hipotesis de que el aceite esencial de clavo de olor afecta la espermatogenesis. La histoquimica de los ovarioles y la fertilidad de S. frugiperda. Los resultados mostraron que el aceite esencial de clavo de olor afecta la gametogenesis de los ovarioles en S. frugiperda, lo que incide negativamente en su reproduccion, demostrando ser una herramienta prometedora para el control de esta plaga.

Efeitos de isolados do fungo Isaria (Persoon) sobre o cupim subterrâneo Coptotermes gestroi (Wasmann) (Isoptera: Rhinotermitidae)

Coptotermes gestroi (Wasmann) is considered to be one of the most destructive species of subterranean termites because of the damage caused on edifications, urban trees, and crops. One alternative to control it is the use of biocontrol agents, such as the entomopathogenic fungi. The genus Isaria (Persoon) has been suggested for the control of subterranean termites, including the Coptotermes genus. Therefore, the present work aim was to select isolates of Isaria pathogenic to C. gestroi. The workers were sprayed with fungi suspensions of I. farinosa, I. fumosoroseaand I. javanica, and evaluated every day to determine mortality. All isolates were pathogenic towards C. gestroi with mortality rates higher than 70%, and virulent, with mean of survival of 2.0 up to 3.9 days. Among the isolates, the ESALQ-1205 isolate of I. farinosa, the ESALQ-1296 isolate of I. fumosorosea, URM-4995 and URM-4993 isolates of I. javanica showed the highest virulence. The estimated CL50 for the ESALQ-1205 isolate of I. farinosa, URM-4995 isolate of I. javanica and ESALQ-1296 isolate of I. fumosorosea was 3.7 x 105, 1.4 x 106and 2.7 x 106 conidia mL-1, respectively. These results suggest high efficiency of these isolates towards the C. gestroi workers. Nevertheless, further studies are necessary to determine a way of using them as well as their efficacy in field.