813 resultados para De Morgan


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Sequence data from the RUBISCO large subunit (rbcL) plastid gene and nuclear small-subunit ribosomal DNA (SSU rDNA) were examined for five samples of Sirodotia delicatula from southeastern Brazil. Data from six North American samples previously identified as S. huillensis and S. suecica were also included in the analysis. Molecular data supported the continued recognition of these three species as separate entities, although one of the North American collections was misidentified. These results were shown to be congruent with morphology, chromosome number and geographic distribution. S. delicatula is more closely related to S. huillensis, both occurring in tropical-subtropical regions, than either to S. suecica with a temperate-boreal distribution. There was little rbcL variation within S. delicatula from Brazil and Costa Rica (the latter a collection previously identified as S. huillensis), with the six samples sequenced diverging from each other by 0-8 bp (0-0.67%). SSU rDNA data set did not provide sufficient resolution to infer phylogenetic relationships among the species of this group due to the low rates of variation (5 bp). Sirodotia was a well-supported clade (100% bootstrap or 1.00 a posteriori probability) based on rbcL sequences. Thus, the results confirm that Sirodotia is a monophyletic group within the Batrachospermales and we continue to recognize it at the generic level. The species S. delicatula, S. huillensis and S. suecica are morphologically and genetically distinct.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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This article documents the addition of 512 microsatellite marker loci and nine pairs of Single Nucleotide Polymorphism (SNP) sequencing primers to the Molecular Ecology Resources Database. Loci were developed for the following species: Alcippe morrisonia morrisonia, Bashania fangiana, Bashania fargesii, Chaetodon vagabundus, Colletes floralis, Coluber constrictor flaviventris, Coptotermes gestroi, Crotophaga major, Cyprinella lutrensis, Danaus plexippus, Fagus grandifolia, Falco tinnunculus, Fletcherimyia fletcheri, Hydrilla verticillata, Laterallus jamaicensis coturniculus, Leavenworthia alabamica, Marmosops incanus, Miichthys miiuy, Nasua nasua, Noturus exilis, Odontesthes bonariensis, Quadrula fragosa, Pinctada maxima, Pseudaletia separata, Pseudoperonospora cubensis, Podocarpus elatus, Portunus trituberculatus, Rhagoletis cerasi, Rhinella schneideri, Sarracenia alata, Skeletonema marinoi, Sminthurus viridis, Syngnathus abaster, Uroteuthis (Photololigo) chinensis, Verticillium dahliae, Wasmannia auropunctata, and Zygochlamys patagonica. These loci were cross-tested on the following species: Chaetodon baronessa, Falco columbarius, Falco eleonorae, Falco naumanni, Falco peregrinus, Falco subbuteo, Didelphis aurita, Gracilinanus microtarsus, Marmosops paulensis, Monodelphis Americana, Odontesthes hatcheri, Podocarpus grayi, Podocarpus lawrencei, Podocarpus smithii, Portunus pelagicus, Syngnathus acus, Syngnathus typhle,Uroteuthis (Photololigo) edulis, Uroteuthis (Photololigo) duvauceli and Verticillium albo-atrum. This article also documents the addition of nine sequencing primer pairs and sixteen allele specific primers or probes for Oncorhynchus mykiss and Oncorhynchus tshawytscha; these primers and assays were cross-tested in both species.

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Sixty-five accessions of the species-rich freshwater red algal order Batrachospermales were characterized through DNA sequencing of two regions: the mitochondrial cox1 gene (664 bp), which is proposed as the DNA barcode for red algae, and the UPA (universal plastid amplicon) marker (370 bp), which has been recently identified as a universally amplifying region of the plastid genome. upgma phenograms of both markers were consistent in their species-level relationships, although levels of sequence divergence were very different. Intraspecific variation of morphologically identified accessions for the cox1 gene ranged from 0 to 67 bp (divergences were highest for the two taxa with the greatest number of accessions; Batrachospermum helminthosum and Batrachospermum macrosporum); while in contrast, the more conserved universal plastid amplicon exhibited much lower intraspecific variation (generally 0-3 bp). Comparisons to previously published mitochondrial cox2-3 spacer sequences for B. helminthosum indicated that the cox1 gene and cox2-3 spacer were characterized by similar levels of sequence divergence, and phylogeographic patterns based on these two markers were consistent. The two taxa represented by the largest numbers of specimens (B. helminthosum and B. macrosporum) have cox1 intraspecific divergence values that are substantially higher than previously reported, but no morphological differences can be discerned at this time among the intraspecific groups revealed in the analyses. DNA barcode data, which are based on a short fragment of an organellar genome, need to be interpreted in conjunction with other taxonomic characters, and additional batrachospermalean taxa need to be analyzed in detail to be able to draw generalities regarding intraspecific variation in this order. Nevertheless, these analyses reveal a number of batrachospermalean taxa worthy of more detailed DNA barcode study, and it is predicted that such research will have a substantial effect on the taxonomy of species within the Batrachospermales in the future.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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In social insects, cuticular hydrocarbons are involved in species, kin, caste and nestmate recognition. Gas chromatography and mass spectrometry were used to compare the cuticular hydrocarbon composition of workers, males and queens of Melipona bicolor. The cuticular hydrocarbon composition of this species was found to consist mainly of C23, C25:1, C25, C27:1, C27, C29:1 and C29, which are already present in imagoes that have not yet abandoned the brood cell. This composition varied quantitatively and qualitatively between and within the castes and sexes. The newly emerged workers and young queens (virgins) had similar cuticular hydrocarbon profiles, which were different from those of the males. When the females start executing their tasks in the colony, the cuticular hydrocarbon profile differences appear. The workers have less variety, while the queens conserve or increase the number of cuticular hydrocarbon compounds. The queens have more abdominal tegumentary glands than the workers, which apparently are the source of the new cuticular compounds.

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We describe differences in the chemical composition of the Dufour gland secretion of virgin and physogastric queens of Melipona bicolor through gas chromatography and mass spectrometry. The Dufour gland secretion of virgin queens consists only of hydrocarbons, while that of physogastric queens contains, besides these, a variety of other compounds, such as isobutyrate and acetate esters. Such differences may indicate the queen fecundity condition and the oxygenated compounds of the physogastrics secretion may help to increase their attractiveness.

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Batrachospermum delicatulum specimens from three stream segments were analyzed from a tropical region in south-eastern Brazil (20°18′- 20°49′S, 49°13′-49°46′W). Physical and chemical parameters and the spatial placement of thalli were investigated along with the reproductive characteristics of the gametophytic phase. Sequence data of the cox 2-3 spacer region was also utilized to evaluate genetic variation in individuals within and among stream segments. Gametophyte occurred under relatively diverse environmental conditions, whereas thalli abundance was weakly or not correlated to environmental variables within the stream segments. All specimens examined were dioecious. The ratio of male/female plants was relatively low (0.5 to 1.3) and male plants tended to occur as clumps (two or three plants together). High reproductive success was observed, as indicated by the occurrence of 100% fertilized (carposporophytic) female plants. This is similar to previous reports for this and other dioecious species, which is remarkable considering the relatively low proportion of male/female plants. Results support the two hypotheses to explain the high reproductive success in dioecious species. The occurrence of male plants in clumps was evidence for a strict spatial relationship (i.e. male plants located in upstream position of female plants in order to release spermatia, which would be carried by eddies through female plants). In contrast, the occurrence of male and female plants adjacent to each other allowed outcrossing among neighboring plants with intermingled male and female branches, which seemed more applicable to some situations (low turbulence habitats). The cox 2-3 spacer region from the 18 individuals sequenced was 376 bp and the DNA sequence was identical with no base pair substitutions. Likewise, a previous study of another Batrachospermum species showed that the same haplotypes were present in all stream segments from the same drainage basin, even though the stream segments were a considerable distance apart. Short distance dispersal either by small birds or waterway connectivity might explain these findings.

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Includes bibliography

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Twenty-five specimens of the freshwater red alga Compsopogon were collected from locations in North America, South America, Europe, Asia, Australasia and Oceania, and from an aquarium, with the goal of determining genetic diversity among specimens and ascertaining the number of phylogenetic species. Specimens were morphologically identified as having either the 'caeruleus' morphology, with regular polyhedral cortical cells, or the 'leptoclados' morphology, with irregular cortical cells with rhizoidal outgrowths. The 'leptoclados' morphology has been used by some researchers to distinguish the genus Compsopogonopsis from Compsopogon, or at least to distinguish C. leptoclados from other Compsopogon species. Sequence data for the rbcL gene and cox1 barcoding region were obtained for most specimens. In addition, SSU and partial LSU (barcode) rDNA were explored for a few specimens, but all sequences were identical. For the 25 newly generated and eight previously published rbcL gene data, there were seven unique haplotypes, but the sequence divergence was very low (≤7 bp, ≤ 0.7%). One haplotype was widespread, represented by 21 specimens from diverse locations in all regions sampled. Likewise, the 22 new and one previously published cox1 barcode region sequences yielded seven unique haplotypes with little sequence divergence (≤13 bp, ≤ 2.0%). One haplotype was widespread, being shared among 16 specimens from all regions. The combined molecular and morphological data showed no genetic differentiation between the 'caeruleus' and 'leptoclados' morphologies. The ubiquitous distribution of Compsopogon in tropical/subtropical regions and its low genetic variation are probably facilitated by the alga's ability to tolerate a wide range of stream conditions and its propagation via asexual spores. Given the findings of previous culture-based studies, morphometric research and field observations, coupled with the results of our study, we conclude there is only a single monospecific genus worldwide and that the species is correctly called C. caeruleus, since this is the oldest validly published name; all other previously described species of Compsopogon and Compsopogonopsis are synonyms. © 2013 British Phycological Society.

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Ethanol (ETOH) consumption has been associated with endocrine and autonomic changes, including the development of hypertension. However, the sequence of pathophysiological events underlying the emergence of this effect is poorly understood. Aims: This study aimed to establish a time-course correlation between neuroendocrine and cardiovascular changes contributing to the development of hypertension following ETOH consumption. Methods: Male adult Wistar rats were subjected to the intake of increasing ETOH concentrations in their drinking water (first week: 5%, second week: 10%, third and fourth weeks: 20% v/v). Results: ETOH consumption decreased plasma and urinary volumes, as well as body weight and fluid intake. Furthermore, plasma osmolality, plasma sodium and urinary osmolality were elevated in the ETOH-treated rats. ETOH intake also induced a progressive increase in the mean arterial pressure (MAP), without affecting heart rate. Initially, this increasein MAP was correlated with increased plasma concentrations of adrenaline and noradrenaline. After the second week of ETOH treatment, plasma catecholamines returned to basal levels, and incremental increases were observed in plasma concentrations of vasopressin (AVP) and angiotensin II (ANG II). Conversely, plasma oxytocin, atrial natriuretic peptide, prolactin and the hypothalamus-pituitary-adrenal axis components were not significantly altered by ETOH. Conclusions: Taken together, these results suggest that increased sympathetic activity may contribute to the early increase in MAP observed inETOHtreated rats. However, the maintenance of this effect may be predominantly regulated by the long-term increase in the secretion of other circulating factors, such as AVP and ANG II, the secretion of both hormones being stimulated by the ETOH-induced dehydration. © The Author 2013. Medical Council on Alcohol and Oxford University Press. All rights reserved.

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Events in Argentina dominated most of the third quarter of 2001 until September 11, when the terrorist attacks against the United States prompted a sell-off of emerging markets assets, increasing uncertainty and risk aversion against a background of global economic slowdown. Emerging markets' short term prospects to tap international capital markets deteriorated significantly. In the third quarter of 2001, Latin American countries issued US$7.6 billion in bonds, following US$11.2 billion in the second quarter and US$13.2 billion in the first quarter, which had been a jump from only US$2.9 billion in the last quarter of 2000. At first, it seemed that the pace of debt issuance would slow down considerably given Argentina's troubles in July, as Argentina's bond auction at the beginning of the month was poorly received, forcing the government to shorten the maturity of the new debt and to pay rates as high as those during the Russian crisis in 1998. By August, however, emerging markets rebounded strongly on the back of a new US$8 billion IMF assistance package to Argentina, with both Mexico and Brazil successfully launching large issues. International markets displayed considerable flexibility as investors gave Mexico's US$1.5 billion 30- year bond and Brazil's JPY200 billion two-year samurai issue a warm reception. This return to capital markets was interrupted by the events of September 11, which caused debt issuance to fall sharply in September and October. Following the events of September 11, EMBI+ spreads widened above 1,000 basis points for the first time in nearly two years. According to J.P. Morgan there was a 3.7% market decline in September, which brought year-to-date returns for the EMBI+ to only 0.06%. Emerging markets debt, however, fared better than most other fixed income and equity markets in the immediate aftermath of the attacks. U.S. high-yield market suffered its worst month since August 1998, declining by 6.5%, while the S&P 500 and Nasdaq declined by 8.2% and 17%, respectively. Emerging equity markets suffered even greater declines, with losses as severe as 24% in local currency terms and 31% in U.S. dollar terms.