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81.
82.
Mayra Chamlian Erick L. Bastos Ceres Maciel Margareth L. Capurro Antonio Miranda Adriana F. Silva Marcelo Der T. Torres Vani X. Oliveira Jr 《Journal of peptide science》2013,19(9):575-580
Controlling the dissemination of malaria requires the development of new drugs against its etiological agent, a protozoan of the Plasmodium genus. Angiotensin II and its analog peptides exhibit activity against the development of immature and mature sporozoites of Plasmodium gallinaceum. In this study, we report the synthesis and characterization of angiotensin II linear and cyclic analogs with anti‐plasmodium activity. The peptides were synthesized by a conventional solid‐phase method on Merrifield's resin using the t‐Boc strategy, purified by RP‐HPLC and characterized by liquid chromatography/ESI (+) MS (LC‐ESI(+)/MS), amino acid analysis, and capillary electrophoresis. Anti‐plasmodium activity was measured in vitro by fluorescence microscopy using propidium iodine uptake as an indicator of cellular damage. The activities of the linear and cyclic peptides are not significantly different (p < 0.05). Kinetics studies indicate that the effects of these peptides on plasmodium viability overtime exhibit a sigmoidal profile and that the system stabilizes after a period of 1 h for all peptides examined. The results were rationalized by partial least‐square analysis, assessing the position‐wise contribution of each amino acid. The highest contribution of polar amino acids and a Lys residue proximal to the C‐terminus, as well as that of hydrophobic amino acids in the N‐terminus, suggests that the mechanism underlying the anti‐malarial activity of these peptides is attributed to its amphiphilic character. Copyright © 2013 European Peptide Society and John Wiley & Sons, Ltd. 相似文献
83.
Internal and surface structures of asci and ascospores were studied by transmission electron microscopy (TEM) and by scanning electron microscopy (SEM) to establish the character and number of ascospores within the ascus of Metschnikowia krissii. Enzyme digestion with snail gut enzymes and SEM examination suggested the presence of a single ascospore enclosed in a thick sheath of epiplasmic materials. Two closely associated ascospores without an epiplasmic sheath were clearly distinguishable from asci of M. bicuspidata var. chathamia when similarly treated. Ultramicrotomy and TEM established conclusively that M. krissii produced a single ascospore per ascus. Neither SEM nor TEM revealed any morphological detail of the ascospores of taxonomic significance. 相似文献
84.
R. D. Reeves A. J. M. Baker T. Becquer G. Echevarria Z. J. G. Miranda 《Plant and Soil》2007,293(1-2):107-119
Major collections of the ultramafic flora of Goiás, central Brazil, were made by Brooks and co-workers in 1988 and 1990. At
the time of reports on this material in 1990–1992 much of it had been identified only tentatively and incompletely, but the
area was clearly interesting for taxonomic and biogeochemical reasons. Further progress has been made but still only two-thirds
of the specimens are identified at the species level. Following a third collection in early 2005, we now have 800 specimens
from this area, with chemical analyses of all the plants and of more than 120 representative soil samples. New species have
been found, e.g., in Paspalum (Poaceae) and Pterolepis (Melastomataceae). There is a need for more taxonomic work in genera such as Cnidoscolus (Euphorbiaceae), Lippia (Verbenaceae), Turnera and Piriqueta (Turneraceae), and Vellozia (Velloziaceae). Ni hyperaccumulation (>1,000 mg/kg in dry plant matter) has now been found in a total of 79 specimens, representing
more than 30 different species. Notable Ni hyperaccumulators include Pfaffia sarcophylla (Amaranthaceae), species of Justicia, Lophostachys and Ruellia (Acanthaceae), Porophyllum (Asteraceae), several species of Lippia (Verbenaceae), Turnera and Piriqueta (Turneraceae), and a possibly new Cnidoscolus (Euphorbiaceae). Ni hyperaccumulation has not been found in plants of the outcrops of Morro Feio or Crominia-Mairipotaba;
it seems to be confined to the extensive layered ultramafics of Barro Alto and the Macedo-Niquelandia areas. The distribution
of Ni-values in the Brazilian plant collection is different from that found in the Mediterranean and California, where there
is a clear distinction between accumulator and non-accumulator plants: in Brazil the distribution is more continuous, and
median Ni concentrations are much greater. An ultramafic hill just north of Niquelandia deserves to be protected because of
the presence there of many of the hyperaccumulators and species probably endemic to the Goiás ultramafics. 相似文献
85.
Ribeiro Brbhara Isabella Oenning Braghin Louizi de Souza Magalhes Lansac-Tha Fernando Miranda Bomfim Francieli Ftima Almeida Bia A. Bonecker Cludia Costa Lansac-Tha Fbio Amdeo 《Hydrobiologia》2022,849(14):3135-3147
Hydrobiologia - Beta diversity is the variability in species composition among sampling units for a given area and can be influenced by several environmental drivers, including environmental... 相似文献
86.
Phenotypic and genotypic profile of clinical and animal multidrug‐resistant Salmonella enterica isolates from Mexico 下载免费PDF全文
S. Aguilar‐Montes de Oca M. Talavera‐Rojas E. Soriano‐Vargas J. Barba‐León J. Vázquez‐Navarrete J. Acosta‐Dibarrat C. Salgado‐Miranda 《Journal of applied microbiology》2018,124(1):67-74
Aims
The objective of this study was to obtain a phenotypic and genotypic profile of Salmonella enterica including multidrug‐resistant (MDR) isolates from food‐producing animals and clinical isolates, as well as their genetic relatedness in two different States of Mexico (Jalisco and State of Mexico).Methods and Results
A total of 243 isolates were evaluated in terms of antimicrobial resistance (AMR) and related genes through a disk diffusion method and PCR respectively; we found 16 MDR isolates, all of them harbouring the blaCMY gene but not qnr genes, these isolates represent less than 10% of the collection. The pulsed‐field gel electrophoresis revealed a higher genotypic similitude within isolates of State of Mexico than Jalisco.Conclusions
A low percentage of Salmonella isolates were resistant to relevant antibiotics in human health, nevertheless, the AMR and involved genes were similar despite the different serovars and origin of the isolates.Significance and Impact of the Study
This investigation provided an insight of the current status of AMR of Salmonella isolates in two States of Mexico and pinpoint the genes involved in AMR and their epidemiological relationship, the information could help to determine an adequate therapy in human and veterinary medicine. 相似文献87.
The receptor occupancy-biological effect relationship for muscarinic receptors in guinea pig ileal smooth muscle has been studied by comparison of radioligand binding and contractile response. Muscarinic receptors in homogenates of ileal smooth muscle were labeled with [3H]-1-Quinuclidinyl benzilate. Treatment with propylbenzilylcholine mustard (PrBCM), to inactivate irreversibly muscarinic receptors, caused a large dose dependent rightward shift of the dose-response curve to three agonistic furtrethonium derivatives with a concomitant decrease in maximal response. Using those data, the fraction of receptors remaining unoccupied (q-values) and "true affinity constants" (-log KA-values) were calculated. Exposure to 20 or 60 nM PrBCM for 15 minutes resulted in a 39% and a 61% reduction in specific [3H]-1-Quinuclidinyl benzilate binding sites respectively to be compared with a 62% and a 85% decrease expected from calculated q-values. KA-values for the methyl and ethyl derivative agreed well with the dissociation constants for the high affinity agonist sites determined from displacement of [3H-]-1-Quinuclidinyl benzilate. The KA-value for the propylfurtrethonium corresponds to the low affinity agonist dissociation constant. The fraction of receptors in the high affinity agonist state differs considerably for the three furtrethonium derivatives investigated. Neither the fraction of receptors in the high affinity agonist state, nor the ratio of dissociation constants for these states is affected by the alkylation of 85% of the functional muscarinic receptors. The inactivation of components of the effector system by PrBCM seems unlikely. 相似文献
88.
Hoekstra M Kruijt JK Van Eck M Van Berkel TJ 《The Journal of biological chemistry》2003,278(28):25448-25453
Hepatic cholesterol(ester) uptake from serum coupled to intracellular processing and biliary excretion are important features in the removal of excess cholesterol from the body. ATP-binding cassette (ABC) transporters play an important role in hepatic cholesterol transport. The liver consists of different cell types, and ABC transporters may exert different physiological functions dependent on the individual cell type. Therefore, in the current study, using real time PCR we compared the mRNA expression of ABC transporters and genes involved in the regulation of cholesterol metabolism in liver parenchymal, endothelial, and Kupffer cells. It appears that liver parenchymal cells contain high expression levels compared with endothelial and Kupffer cells of scavenger receptor class BI ( approximately 3-fold), peroxisome proliferator-activated receptor (PPAR)alpha and PPARgamma (8-20-fold), cholesterol 7alpha-hydroxylase A1 (>100-fold), and ABCG5/G8 ( approximately 5-fold). Liver endothelial cells show a high expression of cholesterol 27-hydroxylase, liver X receptor (LXR)beta, PPARdelta, and ABCG1, suggesting a novel specific role for these genes in endothelial cells. In Kupffer cells, the expression level of LXRalpha, ABCA1, and in particular ABCG1 is high, leading to an ABCG1 mRNA expression level that is 70-fold higher than in parenchymal cells. It can be calculated that 51% of the total liver ABCG1 expression resides in Kupffer cells and 24% in endothelial cells, suggesting an intrahepatic-specific role for ABCG1 in Kupffer and endothelial cells. Because of a specific stimulation of ABCG1 in parenchymal cells by a high cholesterol diet, the contribution of parenchymal cells to the total liver increased from 25 to 60%. Our data indicate that for studies of the role of ABC transporters and their regulation in liver, their cellular localization should be taken into account, allowing proper interpretation of metabolic changes, which are directly related to their (intra)cellular expression level. 相似文献
89.
Danielle M.P. Oliveira Fabio M. Gomes Danielle B. Carvalho Isabela Ramos Alan B. Carneiro Mario A.C. Silva-Neto Wanderley de Souza Ana P.C.A. Lima Kildare Miranda Ednildo A. Machado 《Journal of insect physiology》2013,59(12):1242-1249
Despite being the main insect pest on soybean crops in the Americas, very few studies have approached the general biology of the lepidopteran Anticarsia gemmatalis and there is a paucity of studies with embryo formation and yolk mobilization in this species. In the present work, we identified an acid phosphatase activity in the eggs of A. gemmatalis (agAP) that we further characterized by means of biochemistry and cell biology experiments. By testing several candidate substrates, this enzyme proved chiefly active with phosphotyrosine; in vitro assays suggested a link between agAP activity and dephosphorylation of egg yolk phosphotyrosine. We also detected strong activity with endogenous and exogenous short chain polyphosphates (PolyP), which are polymers of phosphate residues involved in a number of physiological processes. Both agAP activity and PolyP were shown to initially concentrate in small vesicles clearly distinct from typically larger yolk granules, suggesting subcellular compartmentalization. As PolyP has been implicated in inhibition of yolk proteases, we performed in vitro enzymatic assays with a cysteine protease to test whether it would be inhibited by PolyP. This cysteine protease is prominent in Anticarsia egg homogenates. Accordingly, short chain PolyP was a potent inhibitor of cysteine protease. We thereby suggest that PolyP hydrolysis by agAP is a triggering mechanism of yolk mobilization in A. gemmatalis. 相似文献
90.
Catherine M. Phillips Audrey C. Tierney Pablo Perez‐Martinez Catherine Defoort Ellen E. Blaak Ingrid M. F. Gjelstad Jose Lopez‐Miranda Malgorzata Kiec‐Klimczak Malgorzata Malczewska‐Malec Christian A. Drevon Wendy Hall Julie A. Lovegrove Brita Karlstrom Ulf Risérus Helen M. Roche 《Obesity (Silver Spring, Md.)》2013,21(1):E154-E161