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1.
2.
The genus Lutzomyia has great importance in the New World, with some species implicated in the transmission of causal agents of leishmaniases, bartonellosis and arboviruses. From April 2003 to June 2004 an investigation was undertaken on the richness and abundance of the sand fly fauna in the northeast area of Manacapuru county, Amazonas State. The captures were carried out, with 16 light traps CDC, in areas of forest known as terra firme along the highway Manuel Urbano. In the period of 13 months we collected a total of 10,446 sandfly specimens, 3,908 males (38%) and 6,465 females (62%), distributed in 43 species belonging to the genus Lutzomyia, 10 subgenera and six species groups. These results evidenced a diversified and abundant sand fly fauna, with some species not yet reported for Manaus county, close to the study area. 相似文献
3.
In this study, we have compared 34 repetition units of pBuM-2 satellite DNA of individuals from six isolated populations of
Drosophila gouveai, a cactophilic member of Drosophila buzzatii cluster (repleta group). In contrast to the results of previous morphological and molecular data, which suggest differentiation among the
D. gouveai populations, the sequences and the cluster analysis of pBuM-2 monomers showed that this repetitive element is highly conserved
among the six D. gouveai populations (97.8% similarity), indicating a slow rate of evolution of pBuM-2 sequences at the population level. Probably,
some homogenization mechanisms of tandem sequences, such as unequal crossing or gene conversion, have maintained the sequence
similarity of pBuM-2 among D. gouveai populations. Alternatively, such a result may be associated with a functional role of pBuM-2 sequences, although it is not
understood at present. 相似文献
4.
A central composite experimental design leading to a set of 16 experiments with different combinations of pH and temperature was performed to attain the optimal activities of xylose reductase (XR) and xylitol dehydrogenase (XDH) enzymes from Candida mogii cell extract. Under optimized conditions (pH 6.5 and 38°C), the XR and XDH activities were found to be 0.48 U/ml and 0.22 U/ml, respectively, resulting in an XR to XDH ratio of 2.2. Stability, cofactor specificity and kinetic parameters of the enzyme XR were also evaluated. XR activity remained stable for 3 h under 4 and 38°C and for 4 months of storage at −18°C. Studies on cofactor specificity showed that only NADPH-dependent XR was obtained under the cultivation conditions employed. The XR present in C. mogii extracts showed a superior K
m value for xylose when compared with other yeast strains. Besides, this parameter was not modified after enzyme extraction by aqueous two-phase system. 相似文献
5.
The nuclear phenotypes of Malpighian tubule epithelial cells of male nymphs of the blood-sucking insect, Panstrongylus megistus, subjected to short- and long-duration heat shocks at 40oC were analyzed immediately after the shock and 10 and 30 days later. Normal nuclei with a usual heterochromatic body as well as phenotypes indicative of survival (unravelled heterochromatin, giants) and death (apoptosis, necrosis) responses were observed in control and treated specimens. However, all nuclear phenotypes, except the normal ones, were more frequent in shocked specimens. Similarly altered phenotypes have also been reported in Triatoma infestans following heat shock, although at different frequencies. The frequency of the various nuclear phenotypes observed in this study suggests that the forms of cell survival observed were not sufficient or efficient enough to protect all of the Malpighian tubule cells from the deleterious effects of stress. In agreement with studies on P. megistus survival following heat shock, only long-duration shock produced strongly deleterious effects. 相似文献
6.
Franco SJ Rodgers MA Perrin BJ Han J Bennin DA Critchley DR Huttenlocher A 《Nature cell biology》2004,6(10):977-983
Dynamic regulation of adhesion complexes is required for cell migration and has therefore emerged as a key issue in the study of cell motility. Recent progress has been made in defining some of the molecular mechanisms by which adhesion disassembly is regulated, including the contributions of adhesion adaptor proteins and tyrosine kinases. However, little is known about the potential contribution of proteolytic mechanisms to the regulation of adhesion complex dynamics. Here, we show that proteolysis of talin by the intracellular calcium-dependent protease calpain is critical for focal adhesion disassembly. We have generated a single point mutation in talin that renders it resistant to proteolysis by calpain. Quantification of adhesion assembly and disassembly rates demonstrates that calpain-mediated talin proteolysis is a rate-limiting step during adhesion turnover. Furthermore, we demonstrate that disassembly of other adhesion components, including paxillin, vinculin and zyxin, is also dependent on the ability of calpain to cleave talin, suggesting a general role for talin proteolysis in regulating adhesion turnover. Together, these findings identify calpain-mediated proteolysis of talin as a mechanism by which adhesion dynamics are regulated. 相似文献
7.
People's sensitivity to allergies may representone of the most important health factors of thenext century to which attention must be paid inorder to reduce the incidence of social costsand improve the quality of life.Taking into consideration the earnest requestsof the medical-scientific communityEmilia-Romagna ARPA (Regional Agency for thePrevention of the Environment) moved theattention from the monitoring to a short andmedium term prediction of the concentration ofallergenic pollens in the air in order toachieve a more effective therapeutic action.Our main objectives are to improve seasonalforecasts and to interpret anomalous years.A neural network model for grass pollenforecasting has been implemented. Inputvariables were meteorological situations, i.e.,daily temperature (max., min. and average) andrainfall, in addition to combinations ofindividual variables and their thresholds. Theoutput was daily pollen concentration.The model was able to understand and predictanomalous years. We demonstrate that therelationships between pollen concentrations andmeteorological situations are independent fromsite. This means that such models canunderstand the differences in differentareas. 相似文献
8.
Pedro M.G. Soares José Maurício S.C. Mota Emmanuel P. Souza Priscilla F.C. Justino Alvaro X. Franco Fernando Q. Cunha Ronaldo A. Ribeiro Marcellus H.L.P. Souza 《Cytokine》2013,61(1):46-49
Background5-Fluorouracil (5-FU) induces intestinal mucositis, which is characterized by epithelial ulcerations in the mucosa and clinical manifestations, such as pain and dyspeptic symptoms. Cytokines participate in the inflammatory and functional events of intestinal mucositis. IL-4 is an important mediator of intestinal inflammation, with either anti-inflammatory or pro-inflammatory functions, depending on the model of intestinal inflammation. This study aimed to evaluate the role of IL-4 in 5-FU-induced intestinal mucositis.MethodsIL-4+/+ or IL-4?/? mice (25–30 g) were intraperitoneally injected with 5-FU (450 mg/Kg) or saline (C). After 3 days, the mice were sacrificed and the duodenum was evaluated for epithelial damage, MPO activity and cytokine concentration.Results5-FU induced significant damage in the intestinal epithelium of IL-4+/+ mice (reduction in the villus/crypt ratio: control = 3.31 ± 0.21 μm, 5-FU = 0.99 ± 0.10 μm). However, the same treatment did not induce significant damage in IL-4?/? mice (5-FU = 2.87 ± 0.19 μm) compared to wild-type mice. 5-FU-induced epithelial damage increased the MPO activity (neutrophil number) and the level of pro-inflammatory cytokines (IL-4, TNF-α, IL-1β and CXCL-8) in the duodenum. These results were not observed in IL-4?/? mice treated with 5-FU.ConclusionOur data suggest that IL-4 participates as a pro-inflammatory cytokine in a 5-FU-induced intestinal damage model and suggests that IL-4 antagonists may be novel therapeutics for this condition. 相似文献
9.
The piloneural collar in mammalian hairy skin comprises an intricate pattern of circumferential and longitudinal sensory afferents that innervate primary and secondary pelage hairs. The longitudinal afferents tightly associate with terminal Schwann cell processes to form encapsulated lanceolate nerve endings of rapidly adapting mechanoreceptors. The molecular basis for piloneural development, maintenance and function is poorly understood. Here, we show that Nefh-expressing glutamatergic neurons represent a major population of longitudinal and circumferential sensory afferents innervating the piloneural collar. Our findings using a VGLUT2 conditional-null mouse model indicate that glutamate is essential for innervation, patterning and differentiation of NMDAR(+) terminal Schwann cells during piloneural collar development. Similarly, treatment of adult mice with a selective NMDAR antagonist severely perturbed piloneural collar structure and reduced excitability of these mechanosensory neurons. Collectively, these results show that DRG-derived glutamate is essential for the proper development, maintenance and sensory function of the piloneural mechanoreceptor. 相似文献
10.
Latorraca MQ Carneiro EM Mello MA Boschero AC 《The Journal of nutritional biochemistry》1999,10(1):37-43
Changes in (45)Ca uptake and insulin secretion in response to glucose, leucine, and arginine were measured in isolated islets derived from 4-week-old rats born of mothers maintained with normal protein (NP, 17%) or low protein (LP, 6%) diet during pregnancy and lactation. Glucose provoked a dose-dependent stimulation of insulin secretion in both groups of islets, with basal (2.8 mmol/L glucose) and maximal release (27.7 mmol/L glucose) significantly reduced in LP compared with NP islets. In the LP group the concentration-response curve to glucose was shifted to the right compared with the NP group, with the half-maximal response occurring at 16.9 and 13.3 mmol/L glucose, respectively. In LP islets, glucose-induced first and second phases of insulin secretions were drastically reduced. In addition, insulin response to individual amino acids, or in association with glucose, was also significantly reduced in the LP group compared with NP islets. Finally, in LP islets the (45)Ca uptake after 5 minutes or 90 minutes of incubation (which reflect mainly the entry and retention, respectively, of Ca(2+)), was lower than in NP islets. These data indicate that in malnourished rats both initial and sustained phases of insulin secretion in response to glucose were reduced. This poor secretory response to nutrients seems to be the consequence of an altered Ca(2+) handling by malnourished islet cells. 相似文献