998 resultados para RED GIANT BRANCH
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We sequenced 12S RNA mtDNA for the majority of the extant species of sloths and anteaters and compared our results with previous data obtained by our group using 16S RNA mtDNA in the same specimens and to GenBank sequences of the extinct giant sloth Mylodon. Our results suggest that pigmy-anteaters may be a case of the long-branch attraction phenomenon and also show the large genetic difference between the Amazonian and Atlantic forest three-toed sloths, contrasting with the small differences observed between the two non-Atlantic forest forms of sloths. These results have important implications for the taxonomy of sloths and anteaters and strongly suggest the placement of pigmy anteaters in their own family (Cyclopidae) and raising the taxonomic status of Bradypus torquatus to a genus.
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Context. The giant anteater, Myrmecophaga tridactyla, is a large insectivorous mammal from Cerrado which is classified as vulnerable by the IUCN's red list. In spite of frequent giant anteater casualties, there continues to be a lack of published data on how road and landscape attributes affect road-kill rates - information that could prove useful in guiding mitigation measures.Aims. We seek to determine whether road and landscape attributes influence the incidence of road-kills of the giant anteater.Methods. From February 2002 to December 2012 (except for 2004), five roads in two regions in south-eastern Brazil were surveyed twice each month by car. We recorded temporal road-kill data for the giant anteater and related spatial road variables. These variables were also recorded at regular control sites every 2 km. We also took traffic volume data on stretches of the two roads to correlate with road-kills.Key results. Of the 45 anteater casualties recorded, there was a predominance of adult males. On roads MG-428 and SP-334, we found anteater road-kills were more common in the dry season, negatively correlated with traffic volume and related to the presence of native vegetation. Accordingly, road-kill sites tended to occur near the cerrado and grasslands and also appeared more frequently on some straight stretches of roadways. Although it was not shown to influence road-kill rates, topography data does point to regular overpass/underpass locations allowing population connectivity. Termitaria or ant nests were present at all road-kill sites, with 86% having signs of feeding.Conclusions. Native vegetation along roadways, together with straight road design, increases the probability of anteater road-kills by 40.1%.Implications. For mitigation, mowing and removing insect nests on roadsides, as well as roadside wildlife fencing in cerrado and grassland areas is suggested. Warning signs and radar to reduce vehicle speed are recommended for both human safety and anteater conservation. With regard to population connectivity, the absence of aggregated anteater road-kill data in this study meant that there were no particular crossing locations identified. However, the collected topography data do show places that could be used for roadway crossings. The measures indicated may apply to similar species and types of topography on other continents.
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Background: Hystricognath rodents have a lobed placenta, comprising labyrinthine exchange areas and interlobular trophoblast. These correspond to the labyrinthine and spongy zones of other rodent placentae. Beneath them, however, is a structure unique to hystricognath rodents called the subplacenta. We here describe the subplacenta of the red-rumped agouti and examine the possible functional correlates of this structure. Methods: Placentae were collected from early in midgestation to near term of pregnancy and examined by standard histological techniques, immunohistochemistry and transmission electron microscopy. In addition, to study the microvasculature of the subplacenta, vessel casts were inspected by scanning electron microscopy. Results: In the subplacenta, lamellae of connective tissue support a layer of mononuclear cytotrophoblast cells. Beneath this is found syncytiotrophoblast. Clusters of multinuclear giant cells occur in the transition zone between the subplacenta and decidua. There are prominent intercellular spaces between the cytotrophoblast cells. The basal membrane of these cells is often close to fetal blood vessels. The syncytiotrophoblast surrounds an extensive system of lacunae. Microvilli project into these lacunae from the plasma membrane of the syncytiotrophoblast. The syncytial cytoplasm contains electron-dense granules. This is probably the amylase-resistant PAS-positive material identified by histochemistry. The subplacenta is supplied entirely from the fetal circulation. Within it the vessels pursue a tortuous course with sinusoidal dilatations and constrictions. Conclusion: The functions that have been attributed to the subplacenta include hormone production. Our findings are consistent with this interpretation, but suggest that hormone secretion is directed towards the fetal circulation rather than the maternal tissues.
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Red pine (Pinus resinosa Ait.) plantations have been established in Michigan with expectations of mixed final product goals: pulpwood, boltwood and possibly sawlogs. The effects of alternative treatments on tree and stand attributes were examined in: the Atlantic Mine trial, thinned in spring 2006 with three alternatives: (1) every fifth row removal plus crown thinning, (2) every third row removal plus crown thinning and (3) every third row removal plus thinning from below; the Crane Lake trial, thinned in fall 2004 with two alternatives: (1) every third row removal and (2) every third row removal plus thinning from above; the Middle Branch East trial, thinned in fall 2004 with two alternatives: (1) every third row removal plus one in three remaining trees and (2) every third row removal plus one in five remaining trees. All trials included control plots where no thinning was applied. The trials were established in the field as a randomized complete block experiments, in which individual trees were measured in 3-4 fixed-area plots located within each treatment unit. Growth responses of diameter at breast height, height, live crown length, stand basal area and stand volume were examined along with their increments. The Tukey multiple comparison test was used to detect significant differences between treatments in their effect on tree growth response. The results showed that diameter increment increased with increasing thinning intensity and was significantly larger in thinned plots compared to unthinned. Treatments did not substantially affect average tree height increment. Stand basal area increment was significantly larger in the control plot only the year after the harvest. Volume increment was significantly larger in controls, but did not differ considerably among remaining treatments. However, the ratio of volume increment to standing volume was significantly smaller in unthinned plots compared to thinned. Since thinning treatments in all trials hardly ever differed significantly in their effect on stand growth response, mainly due to the relatively short time of the evaluation, heavier thinnings should be favored due to higher volume increment rates and shorter time needed to reach desirable diameters. Nevertheless, economic evaluation based on obtained results will be conducted in the future in order to make final decisions about the most profitable treatment.
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Global climate change and ocean acidification pose a serious threat to marine life. Marine invertebrates are particularly susceptible to ocean acidification, especially highly calcareous taxa such as molluscs, echinoderms and corals. The largest of all bivalve molluscs, giant clams, are already threatened by a variety of local pressures, including overharvesting, and are in decline worldwide. Several giant clam species are listed as 'Vulnerable' on the IUCN Red List of Threatened Species and now climate change and ocean acidification pose an additional threat to their conservation. Unlike most other molluscs, giant clams are 'solar-powered' animals containing photosynthetic algal symbionts suggesting that light could influence the effects of ocean acidification on these vulnerable animals. In this study, juvenile fluted giant clams Tridacna squamosa were exposed to three levels of carbon dioxide (CO2) (control ~400, mid ~650 and high ~950 µatm) and light (photosynthetically active radiation 35, 65 and 304 µmol photons/m**2/s). Elevated CO2 projected for the end of this century (~650 and ~950 µatm) reduced giant clam survival and growth at mid-light levels. However, effects of CO2 on survival were absent at high-light, with 100% survival across all CO2 levels. Effects of CO2 on growth of surviving clams were lessened, but not removed, at high-light levels. Shell growth and total animal mass gain were still reduced at high-CO2. This study demonstrates the potential for light to alleviate effects of ocean acidification on survival and growth in a threatened calcareous marine invertebrate. Managing water quality (e.g. turbidity and sedimentation) in coastal areas to maintain water clarity may help ameliorate some negative effects of ocean acidification on giant clams and potentially other solar-powered calcifiers, such as hard corals.
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Includes indexes.
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Photocopy.
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Mode of access: Internet.
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This study explores the giant oyster Hyotissa hyotis as a novel environmental archive in tropical reef environments of the Indo-Pacific. The species is a typical accessory component in coral reefs, can reach sizes of tens of centimetres, and dates back to the Late Pleistocene. Here, a 70.2-mm-long oxygen and carbon isotope transect through the shell of a specimen collected at Safaga Bay, northern Red Sea, in May 1996, is presented. The transect runs perpendicularly to the foliate and vesicular layers of the inner ostracum near the ligament area of the oyster. The measured d18O and d13C records show sinusoidal fluctuations, which are independent of shell microstructure. The d13C fluctuations exhibit the same wavelength as the d18O fluctuations but are phase shifted. The d18O record reflects the sea surface temperature variations from 1957 until 1996, possibly additionally influenced by the local evaporation. Due to locally enhanced evaporation in the semi-enclosed Safaga Bay, the d18Oseawater value is estimated at 2.17 per mil, i.e., 0.3-0.8 per mil higher than published open surface water d18O values (1.36-1.85 per mil) from the region. The mean water temperature deviates by only 0.4°C from the expected value, and the minimum and maximum values are 0.5°C lower and 2.9°C higher, respectively. When comparing the mean monthly values, however, the sea surface temperature discrepancy between reconstructed and global grid datasets is always <1.0°C. The d13C signal is weakly negatively correlated with regional chlorophyll a concentration and with the sunshine duration, which may reflect changes in the bivalve's respiration. The study emphasises the palaeogeographic context in isotope studies based on fossils, because coastal embayments might not reflect open-water oceanographic conditions.
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Betanodavirus infections have a significant impact through direct losses and trade restrictions for aquaculture sectors in Australia. The giant grouper, Epinephelus lanceolatus, is a high-value, fast-growing species with significant aquaculture potential. With subacute to chronic mortalities reported from a commercial aquaculture facility in northern Queensland, the viral nervous necrosis in the affected fish was confirmed using a RT-qPCR followed by virus isolation using the SSN-1 cell line. The RNA1 and RNA2 segments were sequenced and nucleotide sequences were compared with betanodavirus sequences from GenBank. Phylogenetic analysis revealed that both these sequences clustered with sequences representing red spotted grouper nervous necrosis virus genotype and showed high sequence identity to virus sequences affecting other grouper species. This is the first report confirming infection by betanodavirus in E. lanceolatus from Australia with successful isolation of the virus in a cell culture system, and analysis of nearly full length RNA1 and RNA2 sequences.
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The catastrophic event of red tide has happened in the Strait of Hormuz, the Persian Gulf and Gulf of Oman from late summer 2008 to spring 2009. With its devastating effects, the phenomenon shocked all the countries located in the margin of the Persian Gulf and the Gulf of Oman and caused considerable losses to fishery industries, tourism, and tourist and trade economy of the region. In the maritime cruise carried out by the Persian Gulf and Gulf of Oman Ecological Research Institute, field data, including temperature, salinity, chlorophyll-a, dissolved oxygen and algal density were obtained for this research. Satellite information was received from MODIS and MERIS and SeaWiFS sensors. Temperature and surface chlorophyll images were obtained and compared with the field data and data of PROBE model. The results obtained from the present research indicated that with the occurrence of harmful algal blooms (HAB), the Chlorophyll-a and the dissolved oxygen contents increased in the surface water. Maximum algal density was seen in the northern coasts of the Strait of Hormuz. Less concentration of algal density was detected in deep and surface offshore water. Our results show that the occurred algal bloom was the result of seawater temperature drop, water circulation and the adverse environmental pollutions caused by industrial and urban sewages entering the coastal waters in this region of the Persian Gulf ,This red tide phenomenon was started in the Strait of Hormuz and eventually covered about 140,000 km2 of the Persian Gulf and total area of Strait of Hormuz and it survived for 10 months which is a record amongst the occurred algal blooms across the world. Temperature and chlorophyll satellite images were proportionate to the measured values obtained by the field method. This indicates that satellite measurements have acceptable precisions and they can be used in sea monitoring and modeling.
Direct Visualization Of The Action Of Triton X-100 On Giant Vesicles Of Erythrocyte Membrane Lipids.
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The raft hypothesis proposes that microdomains enriched in sphingolipids, cholesterol, and specific proteins are transiently formed to accomplish important cellular tasks. Equivocally, detergent-resistant membranes were initially assumed to be identical to membrane rafts, because of similarities between their compositions. In fact, the impact of detergents in membrane organization is still controversial. Here, we use phase contrast and fluorescence microscopy to observe giant unilamellar vesicles (GUVs) made of erythrocyte membrane lipids (erythro-GUVs) when exposed to the detergent Triton X-100 (TX-100). We clearly show that TX-100 has a restructuring action on biomembranes. Contact with TX-100 readily induces domain formation on the previously homogeneous membrane of erythro-GUVs at physiological and room temperatures. The shape and dynamics of the formed domains point to liquid-ordered/liquid-disordered (Lo/Ld) phase separation, typically found in raft-like ternary lipid mixtures. The Ld domains are then separated from the original vesicle and completely solubilized by TX-100. The insoluble vesicle left, in the Lo phase, represents around 2/3 of the original vesicle surface at room temperature and decreases to almost 1/2 at physiological temperature. This chain of events could be entirely reproduced with biomimetic GUVs of a simple ternary lipid mixture, 2:1:2 POPC/SM/chol (phosphatidylcholine/sphyngomyelin/cholesterol), showing that this behavior will arise because of fundamental physicochemical properties of simple lipid mixtures. This work provides direct visualization of TX-100-induced domain formation followed by selective (Ld phase) solubilization in a model system with a complex biological lipid composition.
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Propolis is a resin that bees collect from different plant sources and use in the defense of the bee community. The intricate composition of propolis varies depending on plant sources from different geographic regions and many types have been reported. Red coloured propolis found in several states in Brazil and in other countries has known antimicrobial and antioxidant activity. Different analytical methods have been applied to studies regarding the chemical composition and plant origins of red propolis. In this study samples of red propolis from different regions have been characterised using direct infusion electrospray ionisation mass spectrometry (ESI(-)-MS) fingerprinting. Data from the fingerprints was extracted and analysed by multivariate analysis to group the samples according to their composition and marker compounds. Despite similar colour, the red coloured propolis samples were divided into three groups due to contrasting chemical composition, confirming the need to properly characterise the chemical composition of propolis.
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In the Amazon Region, there is a virtual absence of severe malaria and few fatal cases of naturally occurring Plasmodium falciparum infections; this presents an intriguing and underexplored area of research. In addition to the rapid access of infected persons to effective treatment, one cause of this phenomenon might be the recognition of cytoadherent variant proteins on the infected red blood cell (IRBC) surface, including the var gene encoded P. falciparum erythrocyte membrane protein 1. In order to establish a link between cytoadherence, IRBC surface antibody recognition and the presence or absence of malaria symptoms, we phenotype-selected four Amazonian P. falciparum isolates and the laboratory strain 3D7 for their cytoadherence to CD36 and ICAM1 expressed on CHO cells. We then mapped the dominantly expressed var transcripts and tested whether antibodies from symptomatic or asymptomatic infections showed a differential recognition of the IRBC surface. As controls, the 3D7 lineages expressing severe disease-associated phenotypes were used. We showed that there was no profound difference between the frequency and intensity of antibody recognition of the IRBC-exposed P. falciparum proteins in symptomatic vs. asymptomatic infections. The 3D7 lineages, which expressed severe malaria-associated phenotypes, were strongly recognised by most, but not all plasmas, meaning that the recognition of these phenotypes is frequent in asymptomatic carriers, but is not necessarily a prerequisite to staying free of symptoms.
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Frailty and anemia in the elderly appear to share a common pathophysiology associated with chronic inflammatory processes. This study uses an analytical, cross-sectional, population-based methodology to investigate the probable relationships between frailty, red blood cell parameters and inflammatory markers in 255 community-dwelling elders aged 65 years or older. The frailty phenotype was assessed by non-intentional weight loss, fatigue, low grip strength, low energy expenditure and reduced gait speed. Blood sample analyses were performed to determine hemoglobin level, hematocrit and reticulocyte count, as well as the inflammatory variables IL-6, IL-1ra and hsCRP. In the first multivariate analysis (model I), considering only the erythroid parameters, Hb concentration was a significant variable for both general frailty status and weight loss: a 1.0g/dL drop in serum Hb concentration represented a 2.02-fold increase (CI 1.12-3.63) in an individual's chance of being frail. In the second analysis (model II), which also included inflammatory cytokine levels, hsCRP was independently selected as a significant variable. Each additional year of age represented a 1.21-fold increase in the chance of being frail, and each 1-unit increase in serum hsCRP represented a 3.64-fold increase in the chance of having the frailty phenotype. In model II reticulocyte counts were associated with weight loss and reduced metabolic expenditure criteria. Our findings suggest that reduced Hb concentration, reduced RetAbs count and elevated serum hsCRP levels should be considered components of frailty, which in turn is correlated with sarcopenia, as evidenced by weight loss.