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2.
Bruna de Cssia M. Ramos Danessa S. Boligon Gilson R. P. Moreira 《Ecological Entomology》2019,44(5):610-622
1. Larvae of tortoise beetles present exaggerated body parts in association with an abdominal shield, which is made of faeces and exuviae that are deposited on the urogomphi throughout ontogeny. Growth trajectories and scaling relationships of these functional structures associated with the shield, if any, are unknown. 2. This study of Gratiana spadicea first tested, under field conditions, whether there is adaptive value associated with the shield regarding protection against predation and sunlight. Then, under laboratory conditions, the growth trajectory and allometric relationships among body parts were investigated, including scoli, individual and apparent furcae, and shield. The influence of food deprivation on the development of these structures was also determined. 3. Findings from previous studies were confirmed, suggesting that the adaptive value assigned to the shield is related to protection against predators. The present study demonstrated for the first time that the shield acts as a parasol in cassidines, decreasing the exposure of their larval body to sunlight. The scoli and apparent furca are exaggerated structures of G. spadicea, the development of which involves allometric growth and greater energetic investment (positive allometry) during ontogeny. There was proportionally less energetic investment for somatic construction of individual furca (negative allometry) due to the accumulation of the exuviae. 4. The possible consequences, in terms of developmental costs and survivorship benefits associated with the evolution of such exaggerated structures, are discussed. 相似文献
3.
V. Carré‐Missio F.A. Rodrigues D.A. Schurt R.S. Resende N.F.A. Souza D.C. Rezende W.R. Moreira L. Zambolim 《The Annals of applied biology》2014,164(3):396-403
Coffee leaf rust, caused by Hemileia vastatrix, is the most devastating disease of coffee. Since limited information is available in the literature on silicon (Si) affecting plant diseases in coffee, this study was designed to investigate foliar application of potassium silicate (PS), a source of soluble (Si), on infection process of coffee leaf rust at the microscopic level. The foliar Si concentration for plants sprayed with water and PS has no significant difference (0.24 and 0.30 dag kg?1, respectively). X‐ray microanalysis indicated that the deposition of Si on the leaves of the plants that were sprayed with PS was greater in comparison to the leaf samples from the plants sprayed with water. Rust severity on leaves of plants sprayed with water or sprayed with PS reached 44% and 32%, respectively, at 36 days after inoculation (dai). Plates of polymerised PS were observed on the leaf surfaces of the plants sprayed with the product, in contrast to its absence on the leaf surfaces of plants sprayed with water. At 36 dai, a greater number of uredia were observed on the leaf surfaces of plants sprayed with water in comparison to the leaf surfaces of plants sprayed with PS. On fractured leaf tissues that were sprayed with PS, less fungal colonisation was observed in comparison to the leaves of plants sprayed with water. In conclusion, the results of this study suggest that the effect of foliar‐applied Si on the control of the coffee leaf rust development may be attributed to the physical role of the polymerised PS, its osmotic effect against urediniospores germination, or both. 相似文献
4.
Jorge E. Moreira Arthur R. Hand L. A. Håkan Borg Stellan Sandler Michael Welsh Nils Welsh Décio L. Eizirik 《Virchows Archiv. B, Cell pathology including molecular pathology》1991,60(1):337-344
We have previously described a preferential reduction in the secretory response to nutrient secretagogues in pancreatic mouse
islets maintained in culture after in vitro exposure to streptozotocin (SZ). This reduction was associated with an impaired
substrate metabolism at the mitochondrial level. To further clarify this issue, mouse pancreatic islets were exposed in vitro
to 2.2 mM SZ for 30 min. At 4 h after SZ treatment ultrastructural changes were apparent in the endoplasmic reticulum and
Golgi areas of the B-cells. However, 2 and 6 days following SZ exposure the B-cells appeared well preserved, except for a
marked decrease in the number of insulin-containing secretory granules. A morphometric analysis of the B-cells 6 days after
SZ exposure showed a normal B-cell size and a normal volume fraction of B-cell mitochondria. However, there was a decrease
in total islet size and a 13% decrease in the volume fraction of B-cells in the islets. These mouse islets exhibited a decreased
content of the mitochondrial DNA-encoded cytochrome b mRNA, as evaluated by dot-blot analysis. As a whole, the data obtained
indicate that SZ treatment does not induce a decrease in the number of mitochondria or long-lasting ultrastructural damage
to this organelle. However, there is a clear decrease in the cytochrome b mRNA, suggesting that SZ can induce damage to the
mitochondrial DNA. 相似文献
5.
The parathyroid hormone (PTH) acts on bones, intestines, and kidneys to maintain the calcium homeostasis which, in turn, is a main factor in controling the parathyroid (PT) gland activity. In all mammals studied, the chief cells of PT glands changed their size, shape, and cytoplasmic structure due to different functional states which vary the serum calcium levels. The chief cells of the rat PT glands were classified as dark and light. The dark cells may constitute an active form, characterized mainly by the abundant free ribosomes, conspicuous rough endoplasmic reticulum, and GOLGI complexes, greater number of secretory granules (SG) and increased tortuosity of the plasma membranes as compared to the light ones which were considered as a less active type of cells. Due to different calcium requirements in newborn and young rats for the ossification of growing skeleton and in adult and senile rats with consolidate mature bones, the PT glands studied with electron microscope showed various cytological features. The parenchyma of newborn and young PT glands was composed by dark chief cells. The light chief cells were more frequent in adult and senile animals as a less active type of cell. Mature SG were only occasionally observed in dark cells of newborn, young and adult PT glands. They may constitute a reserve supply of PTH but probably not the main way of secretion, according to their little number. Another pool of PTH probably answers the needs for the small basal variations in the steady-state secretion and may be represented by the vesicles observed in the chief cells cytoplasm. 相似文献
6.
I T Toledo e Souza B L Wajchenberg F Prestes Cesar J S Almeida Neto 《Hormones et métabolisme》1983,15(12):575-580
Insulin and C-peptide (free insulin and C-peptide in insulin-treated patients) were measured after glucose stimulation in nine Type II diabetics on chlorpropamide, eleven insulin-treated maturity-onset diabetics and in 8 normal controls. Dissociation between C-peptide and insulin response to glucose was observed in several diabetics. The relation between incremental molar areas under C-peptide and insulin curves, after glucose challenge (delta CPR - delta IRI/delta CPR) were used to evaluate the hepatic insulin extraction in all but the insulin-treated diabetics. The lower insulin requirements and better control of the short-duration insulin-treated maturity-onset diabetics in relation to the long-term ones could not be explained either by the residual insulin secretion or by the level of "insulin antibodies". The chlorpropamide-responsive patients presented higher insulin levels after the glucose challenge and a lower hepatic insulin extraction than the non-responsive ones. 相似文献
7.
Proteins from two species of the genusArtocarpus (A. integrifolia L. andA. incisa L.) were compared by ammonium sulphate fractionation, molecular sieve chromatography and SDS-polyacrylamide gel electrophoresis,
with special attention to the lectins. The protein content and hemagglutinating activity were markedly different in the two
seeds. The protein pattern obtained by both molecular sieve chromatography and SDS-polyacrylamide gel electrophoresis were
quite different. The only similarities found were the elution volume of the lectins in the Sephadex G-100 column and the lectin
bands (11 500 and 15 000 daltons) in SDS-polyacrylamide gel electrophoresis. 相似文献
8.
9.
Maria Ieda Siqueira Linhares Yoshito Eizuru Gildete Patriota de Andrade Ivailda Barbosa Fonseca Luiz Bezerra Carvalho Ivanildo Tenorio Moreira Yoichi Minamishima 《Microbiology and immunology》1994,38(6):475-478
The seroprevalence of human T cell leukemia virus type 1 (HTLV-1) infection was investigated in Brazilians (570): native inhabitants (298) and descendants from Japanese (272) living in Recife and its neighborhoods—North-east of Brazil. Furthermore, polytransfused renal transplanted patients (54) were also examined for the serological status to this virus. The seropositivity to HTLV-1, screened by enzyme-linked immunosorbent assay (ELISA), was low: 1.34% for the local population and 0.73% for the descendants from Japanese. However, the seropositivity for the renal transplanted patients was found to be 11.1%. This higher value suggests that this retrovirus infection seems to be of importance in this clinical condition. 相似文献
10.
J. L. Moreira A. S. Feliciano P. C. Santana P. E. Cruz J. G. Aunins M. J. T. Carrondo 《Cytotechnology》1994,15(1-3):337-349
Natural aggregates of Baby Hamster Kidney cells were grown in stirred vessels operated as repeated-batch cultures during more than 600 hours. Different protocols were applied to passaging different fractions of the initial culture: single cells, large size distributed aggregates and large aggregates. When single cells or aggregates with the same size distribution found in culture are used as inoculum, it is possible to maintain semi-continuous cultures during more than 600 hours while keeping cell growth and viability. These results suggest that aggregate culture in large scale might be feasible, since a small scale culture can easily be used as inoculum for larger vessels without noticeable modification of the aggregate chacteristics. However, when only the large aggregates are used as inoculum, it was shown that much lower cell concentrations are obtained, cell viability in aggregates dropping to less than 60%. Under this selection procedure, aggregates maintain a constant size, larger than under batch experiments, up to approximately 400 hours; after this time, aggregate size increases to almost twice the size expected from batch cultures. 相似文献