962 resultados para plumifer species group


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Consistent leadership of group travel by specific individuals has been documented in many animals. Most species exhibiting this type of leadership have relatively stable group membership. Animals using fission-fusion grouping are not expected to use specific leaders because associations would not be frequent. Certain conditions, however, may allow this type of control over group travel to occur. First, a population would need to be small enough to allow regular associations between individuals. Second, leadership may be useful if the environment where the population in question lives is complex and requires learning to access the resources efficiently. To determine whether fission-fusion species existing under these conditions utilize specific individual leadership, I examined a small residential population of bottlenose dolphins (Tursiops truncatus) in the Lower Florida Keys (LFK) where the benthic habitat is highly complex. My goals were to (1) determine whether specific individuals in this population led group travel more often than expected; (2) determine whether certain factors predicted which animals would lead most often and (3) investigate the benefits of leading to leaders and to followers in a fission-fusion society. Multiple types of data were collected to answer questions posed including dolphin behavior (for leadership analyses), fish sampling (to examine dolphin habitat use under leadership), and dolphin biopsy sampling (for genetic analyses). Results of analyses provided strong evidence for consistent leadership in this population. Leaders were female, most were mothers and on average they had larger measures of centrality within the LFK population. Leaders benefited by leading individuals who were more closely related than expected. Followers benefited from efficient access to profitable habitat. Results build on previous leadership research by expanding our knowledge about the type of species in which specific individuals lead and predictors for what types of individuals may lead. Additionally, results provide the first detailed information about benefits group members obtain by both leading and following.^

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Recent molecular genetic work, combined with morphological comparisons, on Malagasy members of the bat genus Miniopterus (Family Miniopteridae), has uncovered a number of cryptic species. Based on recently collected specimens and associated tissues, we examine patterns of variation in M. aelleni, the holotype of which comes from Ankarana in northern Madagascar. Using molecular genetic (mitochondrial cytochrome b) and morphological characters we describe a new species, M. ambohitrensis sp. nov. In northern Madagascar, M. ambohitrensis and M. aelleni are allopatric, but occur in relatively close geographical contact (approximately 40 km direct line distance) with M. ambohitrensis found at Montagne d'Ambre in montane humid forest and M. aelleni sensu stricto at Ankarana in dry deciduous forest. Morphologically, this new taxon is differentiated from M. aelleni based on pelage coloration, external measurements, craniodental differences, and tragus shape. Comparisons using 725 bp of cytochrome b found a divergence of 1.1% within M. aelleni sensu stricto, 0.8% within M. ambohitrensis, and 3.3% between these two clades. The two sister species do not demonstrate acoustical differences based on recordings made in a flight cage. Miniopterus ambohitrensis is known from four localities in the northern and central portions of Madagascar, all from montane regions and across an elevational range from about 800 to 1600 m; its calculated "Extent of occurrence" is 15,143 km2. It is possible that this species is at least partially migratory.

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NIR and IR spectroscopy has been applied for detection of chemical species and the nature of hydrogen bonding in arsenate complexes. The structure and spectral properties of copper(II) arsenate minerals chalcophyllite and chenevixite are compared with copper(II) sulphate minerals devilline, chalcoalumite and caledonite. Split NIR bands in the electronic spectrum of two ranges 11700-8500 cm-1 and 8500-7200 cm-1 confirm distortion of octahedral symmetry for Cu(II) in the arsenate complexes. The observed bands with maxima at 9860 and 7750 cm-1 are assigned to Cu(II) transitions 2B1g ® 2B2g and 2B1g ® 2A1g. Overlapping bands in the NIR region 4500-4000 cm-1 is the effect of multi anions OH-, (AsO4)3- and (SO4)2-. The observation of broad and diffuse bands in the range 3700-2900 cm-1 confirms strong hydrogen bonding in chalcophyllite relative to chenevixite. The position of the water bending vibrations indicates the water is strongly hydrogen bonded in the mineral structure. The strong absorption feature centred at 1644 cm-1 in chalcophyllite indicates water is strongly hydrogen bonded in the mineral structure. The H2O-bending vibrations shift to low wavenumbers in chenevixite and an additional band observed at 1390 cm-1 is related to carbonate impurity. The characterisation of IR spectra by ν3 antisymmetric stretching vibrations of (SO4)2- and (AsO4)3 ions near 1100 and 800 cm-1 respectively is the result of isomorphic substitution for arsenate by sulphate in both the minerals of chalcophyllite and chenevixite.

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Streptococcus pyogenes, also known as Group A Streptococcus (GAS) has been associated with a range of diseases from the mild pharyngitis and pyoderma to more severe invasive infections such as streptococcal toxic shock. GAS also causes a number of non-suppurative post-infectious diseases such as rheumatic fever, rheumatic heart disease and glomerulonephritis. The large extent of GAS disease burden necessitates the need for a prophylactic vaccine that could target the diverse GAS emm types circulating globally. Anti-GAS vaccine strategies have focused primarily on the GAS M-protein, an extracellular virulence factor anchored to GAS cell wall. As opposed to the hypervariable N-terminal region, the C-terminal portion of the protein is highly conserved among different GAS emm types and is the focus of a leading GAS vaccine candidate, J8-DT/alum. The vaccine candidate J8-DT/alum was shown to be immunogenic in mice, rabbits and the non-human primates, hamadryas baboons. Similar responses to J8-DT/alum were observed after subcutaneous and intramuscular immunization with J8-DT/alum, in mice and in rabbits. Further assessment of parameters that may influence the immunogenicity of J8-DT demonstrated that the immune responses were identical in male and female mice and the use of alum as an adjuvant in the vaccine formulation significantly increased its immunogenicity, resulting in a long-lived serum IgG response. Contrary to the previous findings, the data in this thesis indicates that a primary immunization with J8-DT/alum (50ƒÊg) followed by a single boost is sufficient to generate a robust immune response in mice. As expected, the IgG response to J8- DT/alum was a Th2 type response consisting predominantly of the isotype IgG1 accompanied by lower levels of IgG2a. Intramuscular vaccination of rabbits with J8-DT/alum demonstrated that an increase in the dose of J8-DT/alum up to 500ƒÊg does not have an impact on the serum IgG titers achieved. Similar to the immune response in mice, immunization with J8-DT/alum in baboons also established that a 60ƒÊg dose compared to either 30ƒÊg or 120ƒÊg was sufficient to generate a robust immune response. Interestingly, mucosal infection of naive baboons with a M1 GAS strain did not induce a J8-specific serum IgG response. As J8-DT/alum mediated protection has been previously reported to be due to the J8- specific antibody formed, the efficacy of J8-DT antibodies was determined in vitro and in vivo. In vitro opsonization and in vivo passive transfer confirmed the protective potential of J8-DT antibodies. A reduction in the bacterial burden after challenge with a bioluminescent M49 GAS strain in mice that were passively administered J8-DT IgG established that protection due to J8-DT was mediated by antibodies. The GAS burden in infected mice was monitored using bioluminescent imaging in addition to traditional CFU assays. Bioluminescent GAS strains including the ‘rheumatogenic’ M1 GAS could not be generated due to limitations with transformation of GAS, however, a M49 GAS strain was utilized during BLI. The M49 serotype is traditionally a ‘nephritogenic’ serotype associated with post-streptococcal glomerulonephritis. Anti- J8-DT antibodies now have been shown to be protective against multiple GAS strains such as M49 and M1. This study evaluated the immunogenicity of J8-DT/alum in different species of experimental animals in preparation for phase I human clinical trials and provided the ground work for the development of a rapid non-invasive assay for evaluation of vaccine candidates.

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Agrobacterium is widely considered to be the only bacterial genus capable of transferring genes to plants. When suitably modified, Agrobacterium has become the most effective vector for gene transfer in plant biotechnology1. However, the complexity of the patent landscape2 has created both real and perceived obstacles to the effective use of this technology for agricultural improvements by many public and private organizations worldwide. Here we show that several species of bacteria outside the Agrobacterium genus can be modified to mediate gene transfer to a number of diverse plants. These plant-associated symbiotic bacteria were made competent for gene transfer by acquisition of both a disarmed Ti plasmid and a suitable binary vector. This alternative to Agrobacterium-mediated technology for crop improvement, in addition to affording a versatile ‘open source’ platform for plant biotechnology, may lead to new uses of natural bacteria– plant interactions to achieve plant transformation.

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Reactive oxygen species (ROS) and related free radicals are considered to be key factors underpinning the various adverse health effects associated with exposure to ambient particulate matter. Therefore, measurement of ROS is a crucial factor for assessing the potential toxicity of particles. In this work, a novel profluorescent nitroxide, BPEAnit, was investigated as a probe for detecting particle-derived ROS. BPEAnit has a very low fluorescence emission due to inherent quenching by the nitroxide group, but upon radical trapping or redox activity, a strong fluorescence is observed. BPEAnit was tested for detection of ROS present in mainstream and sidestream cigarette smoke. In the case of mainstream cigarette smoke, there was a linear increase in fluorescence intensity with an increasing number of cigarette puffs, equivalent to an average of 101 nmol ROS per cigarette based on the number of moles of the probe reacted. Sidestream cigarette smoke sampled from an environmental chamber exposed BPEAnit to much lower concentrations of particles, but still resulted in a clearly detectible increase in fluorescence intensity with sampling time. It was calculated that the amount of ROS was equivalent to 50 ± 2 nmol per mg of particulate matter; however, this value decreased with ageing of the particles in the chamber. Overall, BPEAnit was shown to provide a sensitive response related to the oxidative capacity of the particulate matter. These findings present a good basis for employing the new BPEAnit probe for the investigation of particle-related ROS generated from cigarette smoke as well as from other combustion sources.

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Four morphologically cryptic species of the Bactrocera dorsalis fruit fly complex (B. dorsalis s.s., B. papayae, B. carambolae and B. philippinensis) are serious agricultural pests. As they are difficult to diagnose using traditional taxonomic techniques, we examined the potential for geometric morphometric analysis of wing size and shape to discriminate between them. Fifteen wing landmarks generated size and shape data for 245 specimens for subsequent comparisons among three geographically distinct samples of each species. Intraspecific wing size was significantly different within samples of B. carambolae and B. dorsalis s.s. but not within samples of B. papayae or B. philippinensis. Although B. papayae had the smallest wings (average centroid size=6.002 mm±0.061 SE) and B. dorsalis s.s. the largest (6.349 mm±0.066 SE), interspecific wing size comparisons were generally non-informative and incapable of discriminating species. Contrary to the wing size data, canonical variate analysis based on wing shape data discriminated all species with a relatively high degree of accuracy; individuals were correctly reassigned to their respective species on average 93.27% of the time. A single sample group of B. carambolae from locality 'TN Malaysia' was the only sample to be considerably different from its conspecific groups with regards to both wing size and wing shape. This sample was subsequently deemed to have been originally misidentified and likely represents an undescribed species. We demonstrate that geometric morphometric techniques analysing wing shape represent a promising approach for discriminating between morphologically cryptic taxa of the B. dorsalis species complex.

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Drosophila serrata is a member of the montium group, which contains more than 98 species and until recently was considered a subgroup within the melanogaster group. This Drosophila species is an emerging model system for evolutionary quantitative genetics and has been used in studies of species borders, clinal variation and sexual selection. Despite the importance of D. serrata as a model for evolutionary research, our poor understanding of its genome remains a significant limitation. Here, we provide a first-generation gene-based linkage map and a physical map for this species. Consistent with previous studies of other drosophilids we observed strong conservation of genes within chromosome arms homologous with D. melanogaster but major differences in within-arm synteny. These resources will be a useful complement to ongoing genome sequencing efforts and QTL mapping studies in this species

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The African streak viruses (AfSVs) are a diverse group of mastrevirus species (family Geminiviridae) that infect a wide variety of annual and perennial grass species across the African continent and its nearby Indian Ocean islands. Six AfSV species (of which maize streak virus is the best known) have been described. Here we report the full genome sequences of eight isolates of a seventh AfSV species: Urochloa streak virus (USV), sampled from various locations in Nigeria. Despite there being good evidence of recombination in many other AfSV species, we found no convincing evidence that any of the USV sequences were either inter- or intra-species recombinants. The USV isolates, all of which appear to be variants of the same strain (their genome sequences are all more than 98% identical), share less than 69% nucleotide sequence identity with other currently described AfSV species. © 2008 Springer-Verlag.

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Understanding the evolutionary history and phylogenetic relationships between rare and common species is necessary for the effective management of rare species. The genus Cherax, a group of freshwater crayfish species, is of interest in this regard as a number of species are rare or have restricted distributions while other species are common and widespread. Here we describe the characterisation of three novel nuclear genes of the haemocyanin superfamily for phylogenetic reconstruction of the genus. All novel markers developed in this study amplified consistently in species from three divergent clades of the genus Cherax. The level of polymorphism found in these markers was consistently higher than that found in other nuclear genes previously used in invertebrate systematics, such as NaK ATP-ase. In combination, these markers will be useful to delineate phylogenetic relationships between rare and common Cherax species.