443 resultados para subspecies
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Melipona quadrifasciata quadrifasciata and M. quadrifasciata anthidioides are subspecies of M. quadrifasciata, a stingless bee species common in coastal Brazil. These subspecies are discriminated by the yellow stripe pattern of the abdominal tergites. We found Vsp I restriction patterns in the cytochrome b region closely associated to each subspecies in 155 M. quadrifasciata colonies of different geographical origin. This mitochondrial DNA molecular marker facilitates diagnosis of M. quadrifasciata subspecies matrilines and can be used to establish their natural distribution and identify hybrid colonies.
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Background: Plasmodium vivax circumsporozoite variants have been identified in several geographical areas. The real implication of the genetic variation in this region of the P. vivax genome has been questioned for a long time. Although previous studies have observed significant association between VK210 and the Duffy blood group, we present here that evidences of this variation are limited to the CSP central portion. Methods: The phylogenetic analyses were accomplished starting from the amplification of conserved domains of 18 SSU RNAr and Cyt B. The antibodies responses against the CSP peptides, MSP-1, AMA-1 and DBP were detected by ELISA, in plasma samples of individuals infected with two P. vivax CS genotypes: VK210 and P. vivax-like. Results: These analyses of the two markers demonstrate high similarity among the P. vivax CS genotypes and surprisingly showed diversity equal to zero between VK210 and P. vivax-like, positioning these CS genotypes in the same clade. A high frequency IgG antibody against the N- and C-terminal regions of the P. vivax CSP was found as compared to the immune response to the R- and V-repetitive regions (p = 0.0005, Fisher's Exact test). This difference was more pronounced when the P. vivax-like variant was present in the infection (p = 0.003, Fisher's Exact test). A high frequency of antibody response against MSP-1 and AMA-1 peptides was observed for all P. vivax CS genotypes in comparison to the same frequency for DBP. Conclusions: This results target that the differences among the P. vivax CS variants are restrict to the central repeated region of the protein, mostly nucleotide variation with important serological consequences.
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Background: Leifsonia xyli is a xylem-inhabiting bacterial species comprised of two subspecies: L. xyli subsp. xyli (Lxx) and L. xyli subsp. cynodontis (Lxc). Lxx is the causal agent of ratoon stunting disease in sugarcane commercial fields and Lxc colonizes the xylem of several grasses causing either mild or no symptoms of disease. The completely sequenced genome of Lxx provided insights into its biology and pathogenicity. Since IS elements are largely reported as an important source of bacterial genome diversification and nothing is known about their role in chromosome architecture of L. xyli, a comparative analysis of Lxc and Lxx elements was performed. Results: Sample sequencing of Lxc genome and comparative analysis with Lxx complete DNA sequence revealed a variable number of IS transposable elements acting upon genomic diversity. A detailed characterization of Lxc IS elements and a comparative review with IS elements of Lxx are presented. Each genome showed a unique set of elements although related to same IS families when considering features such as similarity among transposases, inverted and direct repeats, and element size. Most of the Lxc and Lxx IS families assigned were reported to maintain transposition at low levels using translation regulatory mechanisms, consistent with our in silico analysis. Some of the IS elements were found associated with rearrangements and specific regions of each genome. Differences were also found in the effect of IS elements upon insertion, although none of the elements were preferentially associated with gene disruption. A survey of transposases among genomes of Actinobacteria showed no correlation between phylogenetic relatedness and distribution of IS families. By using Southern hybridization, we suggested that diversification of Lxc isolates is also mediated by insertion sequences in probably recent events. Conclusion: Collectively our data indicate that transposable elements are involved in genome diversification of Lxc and Lxx. The IS elements were probably acquired after the divergence of the two subspecies and are associated with genome organization and gene contents. In addition to enhancing understanding of IS element dynamics in general, these data will contribute to our ongoing comparative analyses aimed at understanding the biological differences of the Lxc and Lxx.
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Phaethornis longuemareus aethopyga was described by John T. Zimmer in 1950 and treated as a valid subspecies until it was proposed that the three known specimens were hybrids between R ruber and P. rupurumii amazonicus. On the basis of some recently collected specimens, we reevaluated the validity of P. l. aethopyga. Despite showing some differences related to age and sex, all specimens agree in the general plumage pattern and are fully diagnosable when compared with any other taxon of the genus. The hypothesis of a hybrid origin becomes unsustainable when one notes that (1) P. l. aethopyga has characters that are unique and absent in the purported parental species, such as the white outer margins at the base of the rectrices; and (2) P. l. aethopyga occurs far from the distribution of one of the alleged parental species. Furthermore, field data show that P. l. aethopyga has attributes typical of a valid and independent taxon, such as lekking behavior. Therefore, given its overall diagnosis, P. aethopyga could at least be treated as a phylogenetic species. Yet its morphological and vocal distinctiveness with respect to other Phaethornis spp. in the ""Pygmornis group"" is greater than that observed between some species pairs traditionally regarded as separate biological species within the group, which supports its recognition as a species under the biological species concept. Received 13 July 2008, accepted 9 March 2009.
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Whole rice contains several fat-soluble phytochemicals such. as tocopherols, tocotrienols, and gamma-oryzanol which have been reported to possess beneficial health properties. This study was conducted to determine whether brown rice belonging to indica and japonica subspecies were distinguishable from each other regarding the concentration of these compounds by analyzing 32 genotypes. The fat-soluble compounds were analyzed by normal-phase HPLC in a single run. The variability of the compounds analyzed was high, but the mean content of gamma-oryzanol across all samples was significantly higher (P < 0.01) in japonica (246.3 mg/kg) than in indica rice (190.1 mg/kg). Similar differences were found for total vitamin E contents which were 24.2 mg/kg injaponica and 17.1 mg/kg in indica rice, respectively. In japonica rice, alpha-tocopherol, alpha-tocotrienol, and gamma-tocotrienol were the most abundant homologs, while in indica rice the most abundant were gamma-tocotrienol, alpha-tocopherol, and alpha-tocotrienol. A significant Pearson coefficient (0.80, P < 0.001) between alpha-tocopherol and alpha-tocotrienol levels was found, independent of the subspecies. Both compounds were positively correlated to total tocols and gamma-oryzanol contents. Although more studies are needed to evaluate the interference of growing rice in different environments and multiple years, the present study provided information on natural variations of the vitamin E isomers and the gamma-oryzanol contents in different rice genotypes.
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We report the comparative proteomic and antivenomic characterization of the venoms of subspecies cascavella and collilineatus of the Brazilian tropical rattlesnake Crotalus durissus. The venom proteomes of C. d. collilineatus and C. d. cascavella comprise proteins in the range of 4-115 kDa belonging to 9 and 8 toxin families, respectively. Collilineatus and cascavella venoms contain 20-25 main toxins belonging to the following protein families: disintegrin, PLA(2), serine proteinase, cysteine-rich secretory protein (CRISP), vascular endothelial growth factor-like (VEGF), L-amino acid oxidase, C-type lectin-like, and snake venom metalloproteinase (SVMP). As judged by reverse-phase HPLC and mass spectrometry, cascavella and collilineatus share about 90% of their venom proteome. However, the relative occurrence of the toxin families departs among the two C. durissus subspecies venoms. The most notable difference is the presence of the myotoxin crotamine in some C. d. collilineatus specimens (averaging 20.8% of the total proteins of pooled venom), which is absent in the venom of C. d. cascavella. On the other hand, the neurotoxic PLA2 crotoxin represents the most abundant protein in both C. durissus venoms, comprising 67.4% of the toxin proteome in C. d. collilineatus and 72.5% in C. d. cascavella. Myotoxic PLA(2)s are also present in the two venoms albeit in different relative concentrations (18.1% in C. d. cascavella vs. 4.6% in C. d. collilineatus). The venom composition accounts for the clinical manifestations caused by C. durissus envenomations: systemic neurotoxicity and myalgic symptoms and coagulation disturbances, frequently accompanied by myoglobinuria and acute renal failure. The overall compositions of C. d. subspecies cascavella and collilineatus venoms closely resemble that of C. d. terrificus, supporting the view that these taxa can be considered geographical variations of the same species. Pooled venom from adult C.d. cascavella and neonate C.d. terrificus lack crotamine, whereas this skeletal muscle cell membrane depolarizing inducing myotoxin accounts for similar to 20% of the total toxins of venom pooled from C.d. collilineatus and C.d. terrificus from Southern Brazil. The possible relevance of the observed venom variability among the tropical rattlesnake subspecies was assessed by antivenomics using anti-crotalic antivenoms produced at Instituto Butantan and Instituto Vital Brazil. The results revealed that both antivenoms exhibit impaired immunoreactivity towards crotamine and display restricted (similar to 60%) recognition of PLA(2) molecules (crotoxin and D49-myotoxins) from C. d. cascavella and C. d. terrificus venoms. This poor reactivity of the antivenoms may be due to a combination of factors: on the one hand, an inappropriate choice of the mixture of venoms for immunization and, on the other hand, the documented low immunogenicity of PLA(2) molecules. C. durissus causes most of the lethal snakebite accidents in Brazil. The implication of the geographic variation of venom composition for the treatment of bites by different C. durissus subspecies populations is discussed. (C) 2010 Elsevier B.V. All rights reserved.
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Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.
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Qualitative and quantitative analyses of the volatile constituents from resin of Protium heptaphyllum (Aubl.) Marchand subsp. ulei (Swat) Daly (PHU), and Protium heptaphyllum (Aubl.) Marchand subsp. heptaphyllum (PHH), Burseraceae were performed using GC-MS and GC-FID. The resins were collected around the city of Cruzeiro do Sul, state of Acre, Brazil. Essential oils from the two subspecies were extracted by hydrodistillation with a yield of 8.6% (PHU) and 11.3% (PHH); the main components were terpinolene (42.31%) and p-cymene (39.93%) for subspecies ulei (PHU) and heptaphyllum (PHH), respectively.
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v.13:pt.2:no.1(1918)
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v.3:no.10(1903)
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v.1:no.7(1913)
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v.1:no.9(1915)
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v.3:no.15(1904)
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v.3:no.14(1903)
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v.3:no.9(1903)