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61.
Ivanović J Dordević S Ilijin L Janković-Tomanić M Nenadović V 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2002,132(3):555-566
The response of xylophagous Morimus funereus larvae to a direct change of diet demonstrated that the larvae from nutrient-poor substrates, e.g. oak, are very sensitive to such a change. Depending on dietary protein quality and quantity, an increase of proteolytic activity, i.e. an intensified protein metabolism accompanied by changes in body mass gain, was observed. At the same time, amylolytic activity was usually decreased. In the larvae reared on Robert's diet, sensitivity to the switch in diet was lower at the level of proteolytic enzymes that remained at the control level, while amylolytic activity was elevated. If the switch to a new diet was preceded by 7-day-starvation that disturbed nutritional homeostasis, the response of the larvae was similar to that recorded upon a direct switch only after short-term feeding (24 h) upon starvation. Differences in the response to changes in the diet of the larvae from nature, those reared under laboratory conditions and those of different physiological status could be ascribed to plasticity in the expression of the genes coding for proteases and their isoenzymes, as well as to the multi-functionality of some neurosecretory neurons, synthetic products that participate in the regulation of digestive enzyme activities. 相似文献
62.
Phlebotomus sergenti is a natural vector of Leishmania tropica. However, the ability of P. sergenti to transmit L. tropica by bite has not been proven experimentally yet. We have transmitted L. tropica to golden hamsters and BALB/c mice by the bite of P. sergenti. Sand flies and Leishmania both originated from an anthroponotic cutaneous leishmaniasis focus in Urfa, Turkey. P. sergenti females from a laboratory colony were infected by feeding on lesions of needle-inoculated hamsters or mice. Gravid females were allowed to refeed on uninfected hosts 9-15 d after the infective feeding. At the second feeding, some infected females took a full blood meal, while others only a partial one; some females failed to feed at all. The ability of infected females to take a blood meal did not correlate with the parasite transmissibility. In four BALB/c mice, lesions developed after 1-6 months. In two albino hamsters (Mesocricetus auratus), lesions developed 1 month after the infective feeding, and Leishmania could be reisolated from these sites. Another hamster did not develop a lesion; however, the feeding site and the adjacent ear were PCR positive 1 year after infective feeding. Our results show that dissemination to other parts of host body occurs in L. tropica after sand fly bite. Experimental transmission of the parasite confirms that P. sergenti is a natural vector of L. tropica. 相似文献
63.
Yoshinari NH Abrão MG Bonoldi VL Soares CO Madruga CR Scofield A Massard CL da Fonseca AH 《Memórias do Instituto Oswaldo Cruz》2003,98(3):311-318
This paper reports a case of coinfection caused by pathogens of Lyme disease and babesiosis in brothers. This was the first case of borreliosis in Brazil, acquired in Cotia County, State of S o Paulo, Brazil. Both children had tick bite history, presented erythema migrans, fever, arthralgia, mialgia, and developed positive serology (ELISA and Western-blotting) directed to Borrelia burgdorferi G 39/40 and Babesia bovis antigens, mainly of IgM class antibodies, suggestive of acute disease. Also, high frequencies of antibodies to B. bovis was observed in a group of 59 Brazilian patients with Lyme borreliosis (25.4%), when compared with that obtained in a normal control group (10.2%) (chi-square = 5.6; p < 0.05). Interestingly, both children presented the highest titers for IgM antibodies directed to both infective diseases, among all patients with Lyme borreliosis. 相似文献
64.
Pinti M Biswas P Troiano L Nasi M Ferraresi R Mussini C Vecchiet J Esposito R Paganelli R Cossarizza A 《Experimental biology and medicine (Maywood, N.J.)》2003,228(11):1346-1354
Apoptotic death of CD4+ T lymphocytes is a major cause of the immunodeficiency caused by human immunodeficiency virus (HIV), but it is still unclear how this process precisely occurs. To characterize a potentially useful cellular model, we have analyzed the tendency of chronically HIV-infected CD4+ human cell lines of different origin to undergo apoptosis. We studied ACH-2 and U1 lines, derived from the CD4+ T-cell A301 and the promonocytic U937 cell lines, respectively, and induced apoptosis via several stimuli that trigger different pathways. Their capacity to regulate plasma membrane CD95 expression and to produce soluble CD95 was also analyzed. Using staurosporine, TNF-alpha plus cycloheximide, and gamma-radiations, we observed that ACH-2 were more sensitive to programmed cell death than A301, while U1 were less sensitive than U937. Both infected cell types had a lower sensitivity to CD95-induced apoptosis; the analysis of changes in mitochondrial membrane potential corroborated these observations. Plasma membrane CD95 was similarly regulated in all cell types, which, however, presented a different capacity to produce soluble CD95 molecules. Our in vitro results may offer a new perspective for developing further studies on the pathogenesis of HIV infection. A chronically infected cell line of lymphocytic origin is more susceptible to apoptosis than its parental cell type, while infected monocytic cells are less sensitive than their uninfected counterpart. Thus, it is possible to hypothesize that one of the reasons by which circulating monocytes survive and represent a viral reservoir is the capacity of HIV to decrease the sensitivity to apoptosis of this cell type. However, further studies on ex-vivo collected fresh cells, as well as on other cell lines, are urgently needed to confirm such hypothesis. 相似文献
65.
The use of HPLC-MS in T-cell epitope identification 总被引:4,自引:0,他引:4
The hunt for T-cell epitopes is going on because hopes are set on such peptide sequences for diagnosis and vaccine development in the fight against infectious and tumor diseases. In addition to a variety of other techniques used in T-cell epitope identification, mass spectrometers coupled to microcapillary liquid chromatography have now become an important and sensitive tool in separation, detection, and sequence analysis of highly complex natural major histocompatibility complex (MHC) ligand mixtures. In this article, we review the basics of mass spectrometric techniques and their on-line coupling to microcapillary liquid chromatography (microcap-LC). Furthermore, we introduce current strategies for the identification of new T-cell epitopes using microcapillary liquid chromatography-mass spectrometry (microcap-LC-MS). 相似文献
66.
Segura Alejandro M. Holmgren Milena Anabalón Juan J. Fuentes Eduardo R. 《Plant Ecology》1998,139(2):259-264
The hypothesis that high and low intensity human-made fires can produce ecologically different effects in the Chilean matorral is examined. We compared the abundance of naturally established seedlings under shrubs burned by low and high intensity fires on five north and five south facing slopes. On south facing slopes, we found 54 shrubs burned by low intensity fires and only 4 shrubs burned by high intensity fires. In contrast, north facing slopes had approximately the same number of shrubs burned by low and high fire intensity fires (24 versus 19, respectively). We only found seedlings under shrubs burned by low intensity fires and most of them were of Muehlenbeckia hastulata and Trevoa trinervis. Also viable seeds were only found under shrubs burned by low intensity fires. Results indicate that fire intensity can be an important factor determining species distribution patterns in the matorral. 相似文献
67.
Sara Alberghini Elisa Polone Viviana Corich Milena Carlot Flavio Seno Antonio Trovato & Andrea Squartini 《FEMS microbiology letters》2009,292(2):149-161
Cell-to-cell bacterial communication via diffusible signals is addressed and the conceptual framework in which quorum sensing is usually described is evaluated. By applying equations ruling the physical diffusion of the autoinducer molecules, one can calculate the gradient profiles that would occur either around a single cell or at the center of volumes of increasing size and increasing cell densities. Water-based matrices at 25 °C and viscous biofilms at colder temperatures are compared. Some basic consequences relevant for the field of microbial signalling arise. As regards induction, gradient-mixing dynamics between as little as two cells lying at a short distance appears to be sufficient for the buildup of a concentration reaching the known thresholds for quorum sensing. A straight line in which the highest concentrations occur is also created as a consequence of the gradient overlap geometry, providing an additional signal information potentially useful for chemotactic responses. In terms of whole population signalling, it is shown how the concentration perceived by a cell in the center is critically dependent not only on the cell density but also on the size of the biofilm itself. Tables and formulas for the practical prediction of N -acyl homoserine lactones concentrations at desired distances in different cell density biofilms are provided. 相似文献
68.
Joshua M. Thurman Maria Wong Brandon Renner Ashley Frazer-Abel Patricia C. Giclas Melanie S. Joy Diana Jalal Milena K. Radeva Jennifer Gassman Debbie S. Gipson Frederick Kaskel Aaron Friedman Howard Trachtman 《PloS one》2015,10(9)
Background
Recent pre-clinical studies have shown that complement activation contributes to glomerular and tubular injury in experimental FSGS. Although complement proteins are detected in the glomeruli of some patients with FSGS, it is not known whether this is due to complement activation or whether the proteins are simply trapped in sclerotic glomeruli. We measured complement activation fragments in the plasma and urine of patients with primary FSGS to determine whether complement activation is part of the disease process.Study Design
Plasma and urine samples from patients with biopsy-proven FSGS who participated in the FSGS Clinical Trial were analyzed.Setting and Participants
We identified 19 patients for whom samples were available from weeks 0, 26, 52 and 78. The results for these FSGS patients were compared to results in samples from 10 healthy controls, 10 patients with chronic kidney disease (CKD), 20 patients with vasculitis, and 23 patients with lupus nephritis.Outcomes
Longitudinal control of proteinuria and estimated glomerular filtration rate (eGFR).Measurements
Levels of the complement fragments Ba, Bb, C4a, and sC5b-9 in plasma and urine.Results
Plasma and urine Ba, C4a, sC5b-9 were significantly higher in FSGS patients at the time of diagnosis than in the control groups. Plasma Ba levels inversely correlated with the eGFR at the time of diagnosis and at the end of the study. Plasma and urine Ba levels at the end of the study positively correlated with the level of proteinuria, the primary outcome of the study.Limitations
Limited number of patients with samples from all time-points.Conclusions
The complement system is activated in patients with primary FSGS, and elevated levels of plasma Ba correlate with more severe disease. Measurement of complement fragments may identify a subset of patients in whom the complement system is activated. Further investigations are needed to confirm our findings and to determine the prognostic significance of complement activation in patients with FSGS. 相似文献69.
Milena Nasi Sara De Biasi Elena Bianchini Lara Gibellini Marcello Pinti Tiziana Scacchetti Tommaso Trenti Vanni Borghi Cristina Mussini Andrea Cossarizza 《PloS one》2015,10(1)