SCANNING ELECTRON-MICROSCOPY OF THE RHODNIUS-NEGLECTUS (HEMIPTERA) LABIAL SALIVARY-GLANDS AFTER STARVATION

Labial salivary glands are found in the majority of insects. They are relatively large, extend back into the thorax, and in Rhodnius, they are cherry red in color due to a pigment derived from traces of hemoglobin absorbed form the gut. In most insects they are acinous shaped, with long excretion channels that present differentiated regions which from salivary reservoirs. The glands may be relatively simple or complexly branched and convoluted. In Rhodnius they are described as being unilobed with no traces of division. The main duct leaves the gland at its anterior extremity. The acini have different kinds of cells but all of them are seen as sources of secretion. Our material has a different shape due to the fact that the animals spent 20 days under starvation conditions. New data are also obtained through treatment with collagenase and HCl. The importance of the study of these glands lies in the fact that it will further understanding of the transmission of Chagas' disease.

Long-term starvation effects on Mus musculus hepatocyte nuclear phenotypes

Starvation is a physiologic stress and can significantly alter the structure of hepatic cells. This work aims to detect morphological changes in mice hepatocyte under starvation physiologic stress, based on silver staining technique. Fourteen 21 day old male mice (Mus musculus) were used, 5 as control, 5 submitted to 72 hours of starvation, and 4 were refed during 72 hours after 72 hours of starvation. After liver imprint, 15 nuclei per mouse and their respective nucleoli were outlined in millimetric paper and their areas were obtained. The results, in mm2, were transformed into μm2. The number of nucleoli per nuclei were also counted. After starvation, a statistically significant rise in nuclear and nucleolar areas occurred and no significant increase in the number of nucleoli was observed. The refeeding caused a partial recovery of the nuclear area, no significant change in the nucleolar area and a statistically significant increase in the number of nucleoli. Therefore, starvation can be considered as a modifier agent of the chromatinic structure, leading to an increase of the nuclear and nucleolar areas probably due to an increment of RNA and protein synthesis. The recovery of the stress (refeeding) did not presented a decrease of nucleolar area and evidenced a nucleoli fragmentation, probably to increase more the protein synthesis and/or due to its cycle during the interphase.

Analysis of chromatin and nuclear area alterations in triatomines during starvation

In the present study changes in nuclear area and chromatin distribution in the Malpighian tubules of a blood-feeding insect, the vector of Chagas' disease were analysed. Male and female adult insects were dissected, after a starving period of up to 28 days. The Malpighian tubules were fixed and stained by orcein lacto-acetic. The nuclei were analyzed by photomicrography, karyometry and a statistical analysis was performed. It was observed that with the increase of the starvation period there were alterations in the nuclear phenotype, that is, changes in the nuclear area and chromatin extenuation. In males, starting from the second week of starvation, chromatin extenuation was accentuated, and the beginning of nuclear coalition occurred more frequently in the third and fourth starvation weeks. In females, the accentuated chromatin extenuation was observed after the third starvation week, and irregularities in nuclear borders were more frequent. The descriptive statistical analysis of the male and temale nuclear areas revealed that the nuclear areas continued to increase during starvation reaching highest values in the third week. Another outstanding aspect is that in the third starvation week karyometry presented larger heterogeneity with higher standard deviation values for both genders. Therefore, nuclear alterations related to the distribution and extenuation chromatin and increase in nuclear area were observed. These aspects suggest the presence of nuclear metabolic mechanisms that lead to synthesis of specific proteins necessary for the protection and maintenance of the cell during physiologic stress.

Nucleolar changes in malpighian tubules cells of Rhodnius prolixus during starvation

This study focused on nuclear and nucleolar area changes in Malpighian tubule cells of Rhodnius prolixus, an hematophagous insect, vector of Chagas' disease. Male and female adult insects were dissected after a 28-day starvation period, as well as insects which had been fed again after a 30-day starvation period. Malpighian tubules were fixed and silver stained. In both, males and females, nucleolar fusions and regions of nucleolar corpuscles were observed to be differentially impregnated by silver during feeding stress. In the males and females that were fed again, nucleolar corpuscles were partially fusioned, indicating a slight recovery upon the 30-day starvation period. The changes observed in the nucleolar phenotype and in both nuclear and nucleolar areas indicated that, as a result of stress, a more intense, compensatory activity occurred to supply the metabolic rate. The mechanism of this phenomenon may be associated to the decondensation and activation of chromatin that carries rDNA in order to increase rRNA transcription, and,consequently, protein synthesis.

Tomographic index as auxiliary criteria for surgery indication in fracture dislocation of acetabulum posterior wall

There are situations which the tomographic exam is done on the affected hip or situations where the contralateral hip presents abnormalities that make it impossible to compare. In this study we aimed to evaluate a tomographic index that does not require comparison between the both hips. Twenty two patients with unilateral acetabular fracture dislocation with fracture of posterior wall were studied. We established the relationship between the remaining posterior wall and the femoral head diameter (head/wall index-H/W index). We evaluated 45 two-dimensional computed tomography scan in normal hips and established the H/W index. In 45 normal hips we simulated a posterior wall fracture with involvement of 25% and 30% of the posterior wall and calculated the H/W index. We divided into five groups with five different H/W index (fractured group with non surgical treatment; fractured group; normal group; normal group with simulated fracture of 25% and; 30% of the posterior wall). 2.4 was the lowest limit of confidence interval of the group with 25% of the posterior wall fracture. When we analyzed the confidence interval of the 30% fracture group the upper limit of the confidence interval was 2.7, close to the lower limit of the surgical group that was 2.9. Thus, we suggest the 2.4 the H/W index limit as an auxiliary criteria to indicate whether or not to operate. H/W index is helpful to decide whether or not surgery indication in the fracture dislocation of the posterior wall of the acetabulum. © 2012 Fujiki et al.; licensee BioMed Central Ltd.

Feeding strategy with alternate fasting and refeeding: effects on farmed pacu production

P>A 36-day trial was conducted to determine the effects of repetitive periods of food restriction and refeeding on growth and energy metabolism in pacu (Piaractus mesopotamicus). A total 264 juvenile fish (36.9 +/- 2.8 g) were fed with the experimental diet for 36 days using three regimes: (i) feeding daily to satiation (FD); (ii) no feed for 3 days, then feeding the same amount offered to the control groups for the next 3 days (NF/R controlled); and (iii) no feed for 3 days, then feeding to apparent satiation for the next 3 days (NF/R at satiation). The treatments were distributed into four tanks each. WG and SGR were higher in FD group. Fish refed showed hyperphagia just up to the second day of refeeding. The worst feed conversion rate and the lowest protein efficiency ratio were found in fish NF/R controlled. The lowest values of visceral fat somatic index were found in both fasted fish groups, particularly in NF/R at satiation. The LL and glycogen concentrations, and the hepatosomatic index were all elevated in both feed restricted fish. Muscle lipid showed a tendency to decrease after the cycle of fasting and refeeding. Plasma free fatty acids and glucose levels were elevated in fish subjected to feeding restrictions while serum triglycerides levels were reduced. Triiodothyronine levels were significantly depressed in fish from the NF/R-controlled group and remained at the same levels as the control fish in fish NF/R at satiation. Results indicated that fish subjected to cyclic periods of 3-day satiation or controlled feeding after 3-days of fasting were unable to achieve the final body weight of fish fed to satiation after 36 days.

Influência da heparina sódica na ocorrência de laminite eqüina induzida por sobrecarga de carboidratos

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeito de diferentes fontes de carboidrato e da privação de alimento sobre aspectos biológicos de Telenomus remus Nixon (Hymenoptera, Scelionidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Patogenicidade de isolados de três fungos entomopatogênicos a soldados de Atta sexdens sexdens (Linnaeus, 1758) (Hymenoptera : Formicidae)

As formigas cortadeiras atacam diversas culturas agrícolas, pastagens e os reflorestamentos, atuando sobre muitas espécies vegetais. O presente trabalho teve por objetivo avaliar a patogenicidade dos fungos Beauveria bassiana (isolados AM 9 e JAB 06), Metarhizium anisopliae (isolados E 9 e AL) e Paecilomyces farinosus (isolados CG 189 e CG 195) a soldados de Atta sexdens sexdens, em condições de laboratório. Após a coleta em formigueiro isento de produtos fitossanitários, exemplares de soldados foram cuidadosamente separados em grupos de oito indivíduos e, a seguir, banhados em suspensões contendo 1,0 x 10(6), 1,0 x 10(7), 1,0 x 10(8) e 1,0 x 10(9) conídios/mL de cada isolado. em seguida, cada grupo de formigas foi transferido para unidades de câmara úmida e mantido, sem alimentação, a 27 ± 1 ºC. A mortalidade foi verificada diariamente. Os três fungos se mostraram eficientes patógenos, pois provocaram alta mortalidade, matando mais que 80% dos soldados nos quatro primeiros dias após a inoculação. Os melhores isolados foram JAB 06 e AL, na concentração de 1,0 x 10(9) con./mL. Os isolados JAB 06, AL, CG 195 apresentaram maior capacidade de esporular nos cadáveres das formigas e os tempos letais decresceram com o aumento da concentração de conídios usada.

Signal transduction-related responses to phytohormones and environmental challenges in sugarcane

Background: Sugarcane is an increasingly economically and environmentally important C4 grass, used for the production of sugar and bioethanol, a low-carbon emission fuel. Sugarcane originated from crosses of Saccharum species and is noted for its unique capacity to accumulate high amounts of sucrose in its stems. Environmental stresses limit enormously sugarcane productivity worldwide. To investigate transcriptome changes in response to environmental inputs that alter yield we used cDNA microarrays to profile expression of 1,545 genes in plants submitted to drought, phosphate starvation, herbivory and N-2-fixing endophytic bacteria. We also investigated the response to phytohormones (abscisic acid and methyl jasmonate). The arrayed elements correspond mostly to genes involved in signal transduction, hormone biosynthesis, transcription factors, novel genes and genes corresponding to unknown proteins.Results: Adopting an outliers searching method 179 genes with strikingly different expression levels were identified as differentially expressed in at least one of the treatments analysed. Self Organizing Maps were used to cluster the expression profiles of 695 genes that showed a highly correlated expression pattern among replicates. The expression data for 22 genes was evaluated for 36 experimental data points by quantitative RT-PCR indicating a validation rate of 80.5% using three biological experimental replicates. The SUCAST Database was created that provides public access to the data described in this work, linked to tissue expression profiling and the SUCAST gene category and sequence analysis. The SUCAST database also includes a categorization of the sugarcane kinome based on a phylogenetic grouping that included 182 undefined kinases.Conclusion: An extensive study on the sugarcane transcriptome was performed. Sugarcane genes responsive to phytohormones and to challenges sugarcane commonly deals with in the field were identified. Additionally, the protein kinases were annotated based on a phylogenetic approach. The experimental design and statistical analysis applied proved robust to unravel genes associated with a diverse array of conditions attributing novel functions to previously unknown or undefined genes. The data consolidated in the SUCAST database resource can guide further studies and be useful for the development of improved sugarcane varieties.

Small intestine development of laying hens fed different fiber sources diets and crude protein levels

The objective of the presente study was to evaluate the effects on different dietary fiber sources and crude protein levels on the intestinal morphometry of commercial layers. Isa Brown® layers with 48 weeks of age were distributed in a completely randomized experimental design with a 3 x 2 + 1 factorial arrangement, resulting in seven treatments with seven replicates of eight birds each. At the end of the fourth experimental period (28 days each), birds were 64 weeks of age and were randomly chosen (two birds per replicate, totaling 14 birds per treatment), weighed and sacrificed by neck dislocation. Their intestine was dissected and the duodenum, jejunum and ileum were collected for subsequent analysis of intestinal morphometry. Treatments consisted of diets containing three different fiber sources (cottonseed hulls, soybean hulls or rice husks) and two crude protein levels (12% or 16%). Soybean hulls and 16% crude protein level promoted, in general, an increase in villus height and crypt depth in the three intestinal segments. In the duodenum, the control diet resulted in higher villus height and crypt depth relative to the diets containing fiber. In the jejunum, higher crypt depth values. In the ileum, dietary fiber increased villus height as compared to the control diet.

Análise espacial da distribuição longitudinal de sementes de milho em uma semeadora-adubadora de precisão

In the operation of sowing with planter numerous factors interfere with the establishment of the plant stand, among them, the longitudinal distribution of seeds depending on the displacement speed can significantly affect crop productivity.The present study aimed the evaluation of longitudinal distribution of maize seeds in two different speeds of dislocation of a precision grain drill, through classical and geostatistics. A regular grid sample, totalizing 100 points in each area, was built with 10-meter distance among the points. Each sample point comprised 3.6m(2) (1.8 x 2.0) where the percentage of acceptable, double and fail spacing among the plants was measured after sowing at 4.58 and 5.94 km h(-1) speed of dislocation. Classical and geostatistics were used for data analyses. The percentage of acceptable and failed spacing has shown significant difference between 4.58 and 5.94 km h(-1) speed. The results has shown absence of spatial dependence regarding the percentage of the studied spacing (acceptable, fail and double) at both speeds, showing that studies and statistical inferences can occur based on parameters of classical statistics for distances higher than the shortest one used in the sampling.

Avaliação da deposição da calda de pulverização em função da densidade populacional de Brachiaria plantaginea, do volume e do ângulo de aplicação

O presente trabalho teve por objetivo avaliar a quantidade de calda de pulverização depositada nas folhas de Brachiaria plantaginea, em aplicações de pós-emergência precoce, em que se variou o volume de calda de pulverização, a densidade de plantas m-2 e o ângulo de posicionamento da ponta de pulverização na barra de aplicação. Para isso, foram conduzidos três experimentos em condições de laboratório. Nestes estudos, o volume de calda de pulverização foi obtido por meio da variação da velocidade de deslocamento de um veículo composto por plataforma e quatro rolamentos tracionados por um motor elétrico. Foi utilizada a ponta de pulverização XR Teejet 8001 EVS, na pressão de 241,4 kPa. O delineamento experimental utilizado foi o inteiramente casualizado, com cinco repetições. No primeiro experimento, os volumes utilizados foram de 1147,57; 860,68; 573,78; 459,02; 344,27; 229,51; 114,75; e 57,37 L ha-1 de calda de pulverização, com densidade de 600 plantas m-2. No segundo experimento foram estudadas as densidades de 300, 600, 900 e 1.200 plantas m-2; neste caso, utilizou-se o volume de 229,51 L ha-1 de calda de pulverização. No terceiro experimento avaliou-se o posicionamento do ângulo da ponta de pulverização na barra de aplicação e utilizou-se a densidade de 600 plantas m-2. Estudaram-se os ângulos de -30º, -15º, 90º, +15º e +30º e os volumes de calda de pulverização de 198,76; 221,69; 229,51; 221,69; e 198,76 L ha-1, respectivamente. Foram adotados sinais negativos para o sentido de deslocamento do veículo e sinais positivos para o sentido contrário ao deslocamento. As avaliações do depósito de calda de pulverização, na planta e no solo, foram feitas utilizando-se condutividade elétrica. A porcentagem de depósito de calda de pulverização nas plantas de B. plantaginea foi incrementada com a redução do volume de calda pulverizada por hectare. O depósito de calda por planta foi maior nas densidades maiores de plantas. O ângulo de posicionamento da ponta de pulverização na barra de aplicação incrementou o depósito de calda nas plantas de B. plantaginea, quando comparado com o ângulo de 90º.

Insulin and glucose sensitivity, insulin secretion and beta-cell distribution in endocrine pancreas of the fruit bat Artibeus lituratus

The fruit bat Artibeus lituratus absorbs large amounts of glucose in short periods of time and maintains normoglycemia even after a prolonged starvation period. Based on these data, we aimed to investigate various aspects related with glucose homeostasis analyzing: blood glucose and insulin levels, intraperitoneal glucose and insulin tolerance tests (ipGTT and ipITT), glucose-stimulated insulin secretion (2.8, 5.6 or 8.3 mmol/L glucose) in pancreas fragments, cellular distribution of beta cells, and the amount of pAkt/Akt in the pectoral muscle and liver. Blood glucose levels were higher in fed bats (6.88 +/- 0.5 mmol/L) than fasted bats (4.0 +/- 0.8 mmol/L), whereas insulin levels were similar in both conditions. The values of the area-under-the curve obtained from ipGTT were significantly higher when bats received 2 (5.5-fold) or 3 g/kg glucose (7.5-fold) b.w compared to control (saline). These bats also exhibited a significant decrease of blood glucose values after insulin administration during the iplTT. Insulin secretion from fragments of pancreas under physiological concentrations of glucose (5.6 or 8.3 mmol/L) was similar but higher than in 2.8 mmol/L glucose 1.8- and 2.0-fold, respectively. These bats showed a marked beta-cell distribution along the pancreas, and the pancreatic beta cells are not exclusively located at the central part of the islet. The insulin-induced Akt phosphorylation was more pronounced in the pectoral muscle, compared to liver. The high sensitivity to glucose and insulin, the proper insulin response to glucose, and the presence of an apparent large beta-cell population could represent benefits for the management of high influx of glucose from a carbohydrate-rich meal, which permits appropriate glucose utilization. (C) 2010 Elsevier B.V. All rights reserved.