Altura, número de folhas, composição química e produção de massa seca de Estilosantes Campo Grande sob níveis de potássio e zinco / Height, leaf nymber, chemical composition and dry matter production of Stylosanthes Campo Grande at different levels of potassium and zinco

Objetivou-se determinar a altura de plantas, o número de folhas totais e vivas, a composição química e a produção de massa seca, no primeiro corte e aos 21 dias de rebrota, do estilosantes cv. Campo Grande, sob diferentes níveis de potássio (K2O), com e sem zinco (Zn). O experimento foi realizado em esquema fatorial 4 x 2, no delineamento em blocos casualizados, com quatro repetições. Foram utilizados quatro níveis de K2O (0; 120; 240 e 360 mg/dm3), com e sem Zn (0 e 6 mg/dm3). Não houve efeito da interação níveis de K2O e Zn, nem efeitos independentes de níveis de K2O e de Zn sobre as características estruturais do estilosantes cv. Campo Grande. Os valores médios para altura de plantas, número de folhas totais e número de folhas vivas foram de 21,2 cm, 30,2 folhas e 27,2 folhas vivas, respectivamente. A produção de massa seca não variou com os níveis de K2O e Zn com valor médio de 3,7 g/vaso. Não houve efeito da interação níveis de K2O e Zn, nem efeitos independentes de níveis de K2O e Zn sobre os teores de matéria seca e de fibra em detergente neutro, obtendo-se valores médios de 29,3% e 46,9% MS, respectivamente. No entanto, foi observado efeito da interação níveis de K2O e Zn para os teores de proteína bruta, que apresentaram resposta quadrática. A rebrota aumentou de forma linear com os níveis crescentes de K2O. Embora o mais alto teor de proteína bruta tenha sido obtido nos níveis zero de potássio e zinco, a adubação com potássio é vantajosa por incrementar a rebrota aos 21 dias do estilosantes cv. Campo Grande...(AU)

The objective of this study was to determine plant height, total number of leaves, number of live leaves, chemical composition and dry mass production of Stylosanthes cv. Campo Grande at first cut and after 21 days of regrowth at different levels of potassium (K2O) with and without zinc (Zn). The experiment was conducted using a randomized block design in a 4 x 2 factorial scheme consisting of four repetitions. Four levels of K2O (0, 120, 240 and 360 mg/dm3) with and without Zn (0 and 6 mg/dm3) were used. There was no effect of the interaction between K2O and Zn levels on the structural characteristics of Stylosanthes cv. Campo Grande, and no independent effects of the different levels of K2O and Zn were observed. The mean plant height, total number of leaves and number of live leaves were 21.2 cm, 30.2 and 27.2, respectively. Dry mass production did not differ between K2O and Zn levels, with a mean production of 3.7 g/pot. There was also no effect of the interaction between K2O and Zn levels on dry matter and neutral detergent fiber content, and no independent effects of the different levels of K2O and Zn were observed, with mean values of 29.3% and 46.9% dry matter, respectively. However, an effect of the interaction between K2O and Zn levels was observed for crude protein content, which exhibited a quadratic response. Re2growth increased linearly with increasing K2O levels. Although the highest crude protein content was obtained at zero levels of potassium and zinc, potassium fertilization is advantageous since it increases the regrowth of Stylosanthes cv. Campo Grande in 21 days...(AU)

Altura, número de folhas, composição química e produção de massa seca de Estilosantes Campo Grande sob níveis de potássio e zinco / Height, leaf nymber, chemical composition and dry matter production of Stylosanthes Campo Grande at different levels of potassium and zinco

Objetivou-se determinar a altura de plantas, o número de folhas totais e vivas, a composição química e a produção de massa seca, no primeiro corte e aos 21 dias de rebrota, do estilosantes cv. Campo Grande, sob diferentes níveis de potássio (K2O), com e sem zinco (Zn). O experimento foi realizado em esquema fatorial 4 x 2, no delineamento em blocos casualizados, com quatro repetições. Foram utilizados quatro níveis de K2O (0; 120; 240 e 360 mg/dm3), com e sem Zn (0 e 6 mg/dm3). Não houve efeito da interação níveis de K2O e Zn, nem efeitos independentes de níveis de K2O e de Zn sobre as características estruturais do estilosantes cv. Campo Grande. Os valores médios para altura de plantas, número de folhas totais e número de folhas vivas foram de 21,2 cm, 30,2 folhas e 27,2 folhas vivas, respectivamente. A produção de massa seca não variou com os níveis de K2O e Zn com valor médio de 3,7 g/vaso. Não houve efeito da interação níveis de K2O e Zn, nem efeitos independentes de níveis de K2O e Zn sobre os teores de matéria seca e de fibra em detergente neutro, obtendo-se valores médios de 29,3% e 46,9% MS, respectivamente. No entanto, foi observado efeito da interação níveis de K2O e Zn para os teores de proteína bruta, que apresentaram resposta quadrática. A rebrota aumentou de forma linear com os níveis crescentes de K2O. Embora o mais alto teor de proteína bruta tenha sido obtido nos níveis zero de potássio e zinco, a adubação com potássio é vantajosa por incrementar a rebrota aos 21 dias do estilosantes cv. Campo Grande...

The objective of this study was to determine plant height, total number of leaves, number of live leaves, chemical composition and dry mass production of Stylosanthes cv. Campo Grande at first cut and after 21 days of regrowth at different levels of potassium (K2O) with and without zinc (Zn). The experiment was conducted using a randomized block design in a 4 x 2 factorial scheme consisting of four repetitions. Four levels of K2O (0, 120, 240 and 360 mg/dm3) with and without Zn (0 and 6 mg/dm3) were used. There was no effect of the interaction between K2O and Zn levels on the structural characteristics of Stylosanthes cv. Campo Grande, and no independent effects of the different levels of K2O and Zn were observed. The mean plant height, total number of leaves and number of live leaves were 21.2 cm, 30.2 and 27.2, respectively. Dry mass production did not differ between K2O and Zn levels, with a mean production of 3.7 g/pot. There was also no effect of the interaction between K2O and Zn levels on dry matter and neutral detergent fiber content, and no independent effects of the different levels of K2O and Zn were observed, with mean values of 29.3% and 46.9% dry matter, respectively. However, an effect of the interaction between K2O and Zn levels was observed for crude protein content, which exhibited a quadratic response. Re2growth increased linearly with increasing K2O levels. Although the highest crude protein content was obtained at zero levels of potassium and zinc, potassium fertilization is advantageous since it increases the regrowth of Stylosanthes cv. Campo Grande in 21 days...

Ultrastructural and functional analysis of secretory goblet cells in the midgut of the lepidopteran Anticarsia gemmatalis.

Defoliation caused by Anticarsia gemmatalis larvae affects the commercial production of the soybean. Although regulation of the digestion of soybean components has become part of the suggested strategy to overcome problems caused by Anticarsia larvae, few studies have focused on the morphological and cellular aspects of Anticarsia intestinal tissue. We have therefore further analyzed the morphology and ultrastructure of the midgut of 5th instar larvae of A. gemmatalis. Dissected midgut was subjected to chemical or cryo-fixation and then to several descriptive and analytical techniques associated with both light and electron microscopy in order to correlate anatomical and physiological aspects of this organ. Histological analysis revealed typical anatomy composed of a cell layer limited by a peritrophic membrane. The identified lepidoptera-specific goblet cells were shown to contain several mitochondria inside microvilli of the goblet cell cavity and a vacuolar H(+)-ATPase possibly coupled to a K(+)-pumping system. Columnar cells were present and exhibited microvilli dispersed along the apical region that also presented secretory characteristics. We additionally found evidence for the secretion of polyphosphate (PolyP) into the midgut, a result corroborating previous reports suggesting an excretion route from the goblet cell cavity toward the luminal space. Thus, our results suggest that the Anticarsia midgut not only possesses several typical lepidopteran features but also presents some unique aspects such as the presence of a tubular network and PolyP-containing apocrine secretions, plus an apparent route for the release of cellular debris by the goblet cells.

Inorganic polyphosphates are stored in spherites within the midgut of Anticarsia gemmatalis and play a role in copper detoxification.

Inorganic polyphosphates (PolyP) are widespread molecules that have been shown to play a role in metal detoxification and heavy-metal tolerance. In the present report, we investigated the functional role of spherites as PolyP-metal binding stores in epithelial cells of the midgut of Anticarsia gemmatalis, a lepidopteran pest of soybean. PolyP stores were detected by DAPI staining and indirect immunohistochemistry as vesicles distributed in columnar cells and around goblet cell cavities. These PolyP vesicles were identified as spherites by their elemental profile in cell lysates that were partially modulated by P- or V-ATPases. PolyP levels along the midgut were detected using a recombinant exopolyphosphatase assay. When copper was added in the diet of larva, copper detection in spherites by X-ray microanalysis correlated with an increase in the relative phosphorous X-ray signal and with an increase in PolyP levels in epithelia cell lysate. Transmission electron microscopy of chemically fixed or cryofixed and freeze substituted tissues confirmed a preferential localization of spherites around the goblet cell cavity. Taken together, these results suggest that spherites store high levels of PolyP that are modulated during metal uptake and detoxification. The similarity between PolyP granules and spherites herein described also suggest that PolyP is one of the main phosphorous source of spherites found in different biological models. This suggests physiological roles played by spherites in the midgut of arthropods and mechanisms involved in heavy metal resistance among different insect genera.

Inorganic polyphosphate inhibits an aspartic protease-like activity in the eggs of Rhodnius prolixus (Stahl) and impairs yolk mobilization in vitro.

Inorganic polyphosphate (poly P) is a polymer of phosphate residues that has been shown to act as modulator of some vertebrate cathepsins. In the egg yolk granules of Rhodnius prolixus, a cathepsin D is the main protease involved in yolk mobilization and is dependent on an activation by acid phosphatases. In this study, we showed a possible role of poly P stored inside yolk granules on the inhibition of cathepsin D and arrest of yolk mobilization during early embryogenesis of these insects. Enzymatic assays detected poly P stores inside the eggs of R. prolixus. We observed that micromolar poly P concentrations inhibited cathepsin D proteolytic activity using both synthetic peptides and homogenates of egg yolk as substrates. Poly P was a substrate for Rhodnius acid phosphatase and also a strong competitive inhibitor of a pNPPase activity. Fusion events have been suggested as important steps towards acid phosphatase transport to yolk granules. We observed that poly P levels in those compartments were reduced after in vitro fusion assays and that the remaining poly P did not have the same cathepsin D inhibition activity after fusion. Our results are consistent with the hypothesis that poly P is a cathepsin D inhibitor and a substrate for acid phosphatase inside yolk granules. It is possible that, once activated, acid phosphatase might degrade poly P, allowing cathepsin D to initiate yolk proteolysis. We, therefore, suggest that degradation of poly P might represent a new step toward yolk mobilization during embryogenesis of R. prolixus.

Polyphosphate polymers during early embryogenesis of Periplaneta americana.

Inorganic polyphosphates (PolyP) are linear polymers of phosphate (Pi) residues linked by high-energy phosphoanhydride bonds. Despite a wide distribution, their role during insect embryogenesis has not been examined so far. In this study, we show the mobilization of PolyP polymers during the embryogenesis of the cockroach Periplaneta americana. PolyP was detected by enzymatic and fluorimetric assays and found to accumulate in two main sizes by agarose gel electrophoresis. Confocal microscopy showed their presence in small vesicles. In addition, X-ray microanalysis of small vesicles showed considerable amounts of calcium, sodium and magnesium, suggesting an association of PolyP with these elements. Variations of the free Ca+2, Pi and PolyP levels were observed during the first days of embryogenesis. Our results are consistent with the hypothesis that phosphate ions modulate PolyP variation and that PolyP hydrolysis result in increasing free Ca+2 levels. This is the first investigation of PolyP metabolism during embryogenesis of an insect and might shed light on the mechanisms involving Pi storage and homeostasis during this period. We suggest that PolyP, mainly stored in small vesicles, might be involved in the functional control of Ca+2 and Pi homeostasis during early embryogenesis of P. Americana.

An exanthematic disease epidemic associated with coxsackievirus B3 infection in a day care center.

An epidemic of exanthematic illness in a day care center is described. Ten children aged 7 to 13 months were affected by the illness. The exanthem was characterized by nonconfluent macular or maculopapular lesions that appeared on the face, body and limbs. Fifty percent of the infected children had fever of up to 39 degrees C at the beginning of the disease. Coxsackievirus B3 (CB3) was isolated from the stool of one ill child. Paired serum samples were obtained from eight ill children and six of them presented seroconversion to CB3. Antibodies to CB3 were detected at titers higher than 16 in a single serum sample collected from the other two patients. Neutralizing antibodies to CB3 were detected in 71.0% of the contact children.