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1.
Territoriality carries costs and benefits, which are commonly affected by the spatial and temporal abundance and predictability of food, and by intruder pressure. Giant otters (Pteronura brasiliensis) live in groups that defend territories along river channels during the dry season using chemical signals, loud vocalizations and agonistic encounters. However, little is known about the territoriality of giant otters during the rainy season, when groups leave their dry season territories and follow fish dispersing into flooded areas. The objective of this study was to analyze long-term territoriality of giant otter groups in a seasonal environment. The linear extensions of the territories of 10 giant otter groups were determined based on locations of active dens, latrines and scent marks in each season. Some groups overlapped the limits of neighboring territories. The total territory extent of giant otters was correlated with group size in both seasons. The extent of exclusive territories of giant otter groups was negatively related to the number of adults present in adjacent groups. Territory fidelity ranged from 0 to 100% between seasons. Some groups maintained their territory for long periods, which demanded constant effort in marking and re-establishing their territories during the wet season. These results indicate that the defense capacity of groups had an important role in the maintenance of giant otter territories across seasons, which may also affect the reproductive success of alpha pairs. 相似文献
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Alessandra Bertassoni Guilherme Mourão Rullian César Ribeiro Clarice Silva Cesário Juliana Paula de Oliveira Rita de Cassia Bianchi 《Studies on Neotropical Fauna and Environment》2017,52(1):68-74
This study analyzes a giant anteater’s (Myrmecophaga tridactyla) movement patterns and space use in São Paulo, Brazil. It is the first study to track a giant anteater with Iridium-GPS. The anteater traveled an average distance of 1326 m day–1 with an average speed of 1.04 m min–1. Home range by Kernel was 2.46 km2 while the core area was 0.75 km2, and estimates by Brownian bridge and minimum convex polygon were also provided. The anteater used shrub savanna, open savanna, and water habitats more than expected. Monitoring ended just after 10 days when the female giant anteater’s GPS was found on an illegal trail. 相似文献
3.
Guilherme H.M. Salvador Rafael J. Borges Bruno Lomonte Matthew R. Lewin Marcos R.M. Fontes 《Biochimica et Biophysica Acta (BBA)/General Subjects》2021,1865(7):129913
BackgroundThe treatment for snakebites is early administration of antivenom, which can be highly effective in inhibiting the systemic effects of snake venoms, but is less effective in the treatment of extra-circulatory and local effects. To complement standard-of-care treatments such as antibody-based antivenoms, natural and synthetic small molecules have been proposed for the inhibition of key venom components such as phospholipase A2 (PLA2) and PLA2-like toxins. Varespladib (compound LY315920) is a synthetic molecule developed and clinically tested aiming to block inflammatory cascades of several diseases associated with high PLA2s. Recent studies have demonstrated this molecule is able to potently inhibit snake venom catalytic PLA2 and PLA2-like toxins.MethodsIn vivo and in vitro techniques were used to evaluate the inhibitory effect of varespladib against MjTX-I. X-ray crystallography was used to reveal details of the interaction between these molecules. A new methodology that combines crystallography, mass spectroscopy and phylogenetic data was used to review its primary sequence.ResultsVarespladib was able to inhibit the myotoxic and cytotoxic effects of MjTX-I. Structural analysis revealed a particular inhibitory mechanism of MjTX-I when compared to other PLA2-like myotoxin, presenting an oligomeric-independent function.ConclusionResults suggest the effectiveness of varespladib for the inhibition of MjTX-I, in similarity with other PLA2 and PLA2-like toxins.General significanceVarespladib appears to be a promissory molecule in the treatment of local effects led by PLA2 and PLA2-like toxins (oligomeric dependent and independent), indicating that this is a multifunctional or broadly specific inhibitor for different toxins within this superfamily. 相似文献
4.
When Bergmann's rule fails: evidences of environmental selection pressures shaping phenotypic diversification in a widespread seabird 下载免费PDF全文
Organisms tend to exhibit phenotypes that can be shaped by climate, commonly demonstrating clinal variations along latitudinal gradients. In vertebrates, air temperature plays a major role in shaping body size in both ectothermic and endothermic animals. However, additional small‐scale environmental factors can also act as selection pressures in the marine ecosystem (e.g. primary productivity), evidencing multi‐scale processes acting on marine organisms. In this study, we tested Bergmann's rule in a widely distributed seabird, the brown booby Sula leucogaster, in addition to evaluating the relationship of sea surface temperature and chlorophyll α with phenotypes. We used traits from a morphometric dataset (culmen, wing chord, and tarsus length) and body mass of 276 brown boobies distributed on six breeding sites along a latitudinal gradient in the South Atlantic Ocean (0–27°S). We found significant differentiation among colonies, but phenotypic similarities were observed between colonies located at the extremes of the latitudinal gradient. As the colony nearest to the Equator, Saint Peter and Saint Paul archipelago, had the largest and heaviest individuals, the model containing only air temperature explained < 5% of the allometric variation, providing no substantial support for Bergmann's rule. However, when we added the interaction of chlorophyll α and sea surface temperature the deviance explained rose to over 80%. Primary productivity and sea surface temperature do not follow a latitudinal gradient in the ocean and, therefore, the role of small‐scale oceanographic processes in shaping body size and the importance of considering additional environmental variables when testing Bergmann's rule in marine organisms are evident. 相似文献
5.
Carlos H. Dumard Shana P. C. Barroso Guilherme A. P. de Oliveira Carlos A. M. Carvalho Andre M. O. Gomes José Nelson S. S. Couceiro Davis F. Ferreira Dirlei Nico Andrea C. Oliveira Jerson L. Silva Patrícia S. Santos 《PloS one》2013,8(11)
Whole inactivated vaccines (WIVs) possess greater immunogenicity than split or subunit vaccines, and recent studies have demonstrated that WIVs with preserved fusogenic activity are more protective than non-fusogenic WIVs. In this work, we describe the inactivation of human influenza virus X-31 by high hydrostatic pressure (HHP) and analyze the effects on the structure by spectroscopic measurements, light scattering, and electron microscopy. We also investigated the effects of HHP on the glycoprotein activity and fusogenic activity of the viral particles. The electron microscopy data showed pore formation on the viral envelope, but the general morphology was preserved, and small variations were seen in the particle structure. The activity of hemagglutinin (HA) during the process of binding and fusion was affected in a time-dependent manner, but neuraminidase (NA) activity was not affected. Infectious activity ceased after 3 hours of pressurization, and mice were protected from infection after being vaccinated. Our results revealed full viral inactivation with overall preservation of viral structure and maintenance of fusogenic activity, thereby conferring protection against infection. A strong response consisting of serum immunoglobulin IgG1, IgG2a, and serum and mucosal IgA was also detected after vaccination. Thus, our data strongly suggest that applying hydrostatic pressure may be an effective method for developing new vaccines against influenza A as well as other viruses. 相似文献
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Structural and ecophysiological adaptations to forest gaps 总被引:2,自引:0,他引:2
Guilherme R. Rabelo Ângela P. Vitória Marcos V. A. da Silva Ricardo A. Cruz Elis I. B. Pinho Douglas R. Ribeiro Anita V. Freitas Maura Da Cunha 《Trees - Structure and Function》2013,27(1):259-272
To survive new microclimatic conditions of a forest gap environment, plant species must physiologically and structurally adjust. A morpho-anatomical, ultrastructural and ecophysiological study was performed at three different times in a forest gap that was created by illegal selective logging. The study followed the early successional Actinostemon verticillatus and the late-successional Metrodorea brevifolia, to elucidate the adaptive strategies of acclimation to gaps. Additionally, Schinus terebinthifolius was included in the study in order to test the plasticity of a pioneer species that grows on forest edges, where this species had higher values of leaf thickness, leaf mass area and succulence. M. brevifolia had succulent leaves, high leaf area and a thin cuticle. A. verticillatus presented the densest leaves and was the only species to show leaf morpho-anatomical plasticity. Ultrastructural and physiological differences were observed only in A. verticillatus and M. brevifolia leaves from the gap: increase in the stroma volume, oil droplets, plastoglobuli, photochemical and non-photochemical quenching. Photosynthetic efficiency showed that the early stages of gap formation are the most critical. Acclimation strategies of A. verticillatus suggest this species invests in the efficiency of photosynthesis by increasing its leaf thickness, leaf mass area and in water content maintenance by increasing the density of its leaves, at the expense of gas exchange, was compensated by a high density of stomata. M. brevifolia compensates for the higher cost of leaves and lower leaf plasticity with ultrastructural changes that are used to adjust the photosynthetic process, which promotes a shorter leaf payback time. 相似文献
9.
Synthesis of a novel superabsorbent hydrogel by copolymerization of acrylamide and cashew gum modified with glycidyl methacrylate 总被引:5,自引:0,他引:5
Marcos R. Guilherme Adriano V. Reis Sulen H. Takahashi Adley F. Rubira Judith P.A. Feitosa Edvani C. Muniz 《Carbohydrate polymers》2005,61(4):464-471
Novel superabsorbent hydrogels were manufactured using chemically modified cashew gum (CGMA) and acrylamide (AAm) as reactants. The route for the synthesis was feasible due to the incorporation of glycidyl methacrylate (GMA) into structure of cashew gum (CG) to form the cashew gum-methacrylated (CGMA), in an appropriate mixture water-DMSO, as solvent, and using TEMED as catalyst. Thereafter, the CGMA was copolymerized with AAm yielding (CGMA-co-AAm) hydrogels. The main characteristics of raw and the modified materials are reported in this paper. 13C NMR, 1H NMR and FTIR spectroscopies confirmed the incorporation of vinyl groups, from GMA, into CG structure. By the spectrophotometry analyses, it was found that, ca. 82% of GMA was incorporated to the CG after 24 h of reaction. The cross-linking of CGMA or co-polymerization of CGMA with acrylamide leads to a hydrogel formation. Their gelation was characterized by FT-IR analysis. Alkaline hydrolysis at 40 °C for 3 and 4.5 h increased the water uptake (WU) capacity. Hydrolyzed CGMA-co-AAm hydrogels present higher values of WU (up to 1500) and may be classified as water superabsorbent material. Applications in agriculture, as soil conditioner, and in biomedical field, as biomaterial (scaffold) are being investigated. 相似文献
10.
Vagner Oliveira-Carvalho Miguel Morita Fernandes da Silva Guilherme Veiga Guimarães Fernando Bacal Edimar Alcides Bocchi 《Molecular biology reports》2013,40(3):2663-2670
MicroRNAs (miRNAs) are a class of non-coding small RNAs representing one of the most exciting areas of modern medical science. miRNAs modulate a large and complex regulatory network of gene expression of the majority of the protein-coding genes. Currently, evidences suggest that miRNAs play a crucial role in the pathogenesis of heart failure. Some miRNAs as miR-1, miR-133 and miR-208a are highly expressed in the heart and strongly associated with the development of cardiac hypertrophy. Recent data indicate that these miRNAs as well as miR-206 change their expression quickly in response to physical activity. The differential regulation of miRNAs in response to exercise suggests a potential value of circulating miRNAs (c-miRNAs) as biomarkers of physiological mediators of the cardiovascular adaptation induced by exercise. Likewise, serum levels of c-miRNAs such as miR-423-5p have been evaluated as potential biomarkers in the diagnosis and prognosis of heart failure. On the other hand, the manipulation of miRNAs levels using techniques such as ‘miR mimics’ and ‘antagomiRs’ is becoming evident the enormous potential of miRNAs as promising therapeutic strategies in heart failure. 相似文献