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1.
Phylogeography and population differentiation in the Psittacanthus calyculatus (Loranthaceae) mistletoe: a complex scenario of climate–volcanism interaction along the Trans‐Mexican Volcanic Belt 下载免费PDF全文
2.
David L. Lentz Maria Luisa Reyna de Aguilar Raul Villacorta Helen Marini 《Economic botany》1996,50(1):108-114
Paleoethnobotanical studies in the Zapotitdn Valley of north-central El Salvador revealed that a species of grass,Trachypogon plumosus, was in common use as a thatch material at the Ceren site, a small mesoamerican farming community inundated by volcanic ash circaa.d. 590. Although the grass must have been common in Precolumbian times, repeated attempts to collect fresh specimens from the modern valley were unsuccessful. A survey of the major herbaria with collections from El Salvador likewise demonstrated a lack of modern specimens from the Zapotitdn Valley. The elimination of theT. plumosus from this area and its characteristic savanna habitat probably occurred as a result of the introduction of competing Old World grasses and excessive herbivory. This finding demonstrates why conservationists working in the tropics should be concerned not only with the extinction of rain forest habitats, but with the elimination of other habitats as well. 相似文献
3.
Martha L. Bohórquez Alonso Jorge Martínez Cotrina David Aguilar Pardo Enrique Font Miguel Molina-Borja 《Journal of Ethology》2010,28(2):305-311
Many vertebrate species show display behaviors when predators are in their vicinity. Some of these displays may inform the
predator of the improbability of capturing the prey (i.e., pursuit-deterrent displays) and are potentially advantageous to
both predator and prey. Here we present data on a tail display performed by Gonatodes albogularis, a diurnal tropical gecko. We performed transect surveys in three habitats near Bogotá in Colombia. Geckos detected during
transects were approached by the observer in a standardized way, and details of their tail-waving displays were recorded.
In control recordings animals were watched from a distant site without approaching them. Results showed sexual differences
in tail-waving display: when approached by the observer, males performed this behavior more frequently than females. We found
no significant differences between males and females in flight-initiation distances and height above the substratum when they
were initially located. Results also showed that males displayed more frequently when approached than when the simulated predator
remained stationary. We interpret these results as evidence that the display functions as a pursuit-deterrent signal to potential
predators. However, as some tail displays were performed in the presence of conspecifics, the display may also have a social
function. 相似文献
4.
Summary We have observed a large Mexican American family segregating for a low activity allele at the phosphoglucomutase-1 locus. The deficient allele is detectable by starch gel electrophoresis and by direct activity determination. The presence of the deficient allele in either the homozygous or heterozygous condition is not associated with any other phenotypic finding. 相似文献
5.
A parsimony analysis of 133 sequences of the nuclear ribosomal DNA ITS1 + 5.8S + ITS2 region from 71 taxa in Armeria was carried out. The presence of additive polymorphic sites (APS; occurring in 14 accessions) fits the reticulate scenario proposed in previous work for explaining the ITS pattern of variation on a much smaller scale and is based mainly on the geographical structure of the data, irrespective of taxonomic boundaries. Despite the relatively low bootstrap values and large polytomies, part of which are likely due to disruptive effects of reticulation and concerted evolution in these multicopy sequences, the ITS analysis has phylogenetic and biogeographic implications. APS detected in this study are consistent with hypothesized hybridization events, although biased concerted evolution, previously documented in the genus, needs to be invoked for specific cases and may be responsible for a possible “sink” effect in terminals from a large clade. The causes for sequences of the same species appearing in different clades (here termed transclade) are discussed. 相似文献
6.
A simple, fast and highly reproducible microtest was developed for in vitro adherence studies. A rat epithelial cell line was investigated for the adherence of clinical and subclinical ovine and bovine Staphylococcus aureus strains isolated from mastitis. Staphylococcus aureus strains differed in their ability to adhere to epithelial cells, the degree of adherence being dependent on the concentration of bacteria used in the test. 相似文献
7.
Esmeralda Parra-Peralbo Manuel Pineda Miguel Aguilar 《Molecular biology reports》2009,36(8):2249-2258
A gene encoding a putative asparagine synthetase (AS; EC 6.3.5.4) has been isolated from common bean (Phaseolus vulgaris). A 2.4 kb cDNA clone of this gene (PVAS3) encodes a protein of 570 amino acids with a predicted molecular mass of 64,678 Da, an isoelectric point of 6.45, and a net
charge of −5.9 at pH 7.0. The PVAS3 protein sequence conserves all the amino acid residues that are essential for glutamine-dependent
AS, and PVAS3 complemented an E. coli asparagine auxotroph, that demonstrates that it encodes a glutamine-dependent AS. PVAS3 displayed significant similarity
to other AS. It showed the highest similarity to soybean SAS3 (92.9% identity), rice AS (73.7% identity), Arabidopsis ASN2 (73.2%) and sunflower HAS2 (72.9%). A phylogenetic analysis revealed that PVAS3 belongs to class-II asparagine synthetases. Expression analysis by real-time RT-PCR revealed that PVAS3 is expressed ubiquitously and is not repressed by light. 相似文献
8.
9.
Xavier Moll Felix García Rosa Isabel Ferrer Laura Santos Adrià Aguilar Anna Andaluz 《PloS one》2014,9(4)
The aim of the study was to determine the distribution of different volumes of methylene blue solution injected into the epidural space in anaesthetized pregnant and non-pregnant sheep, to evaluate its cranial distribution and to compare between them. Fifteen pregnant and fifteen non-pregnant sheep were included in the study. Sheep were anaesthetized and received 0.05, 0.1, or 0.2 mL/kg of a lumbosacral epidural solution containing 0.12% methylene blue in 0.9% saline. Thirty minutes after the epidural injection, the ewes were euthanized. The extension of the dye within the epidural space was measured, and the correlation between the volume of the dye injected and the number of stained vertebrae was evaluated. The cranial migration of the dye between pregnant and non-pregnant sheep was also compared. The results show that the volume of methylene blue injected epidurally into pregnant and non-pregnant sheep correlated directly with its cephalic distribution into the epidural space; and a volume of 0.1 mL/kg or 0.2 mL/kg stained up to the first lumbar segment in pregnant and non-pregnant sheep, respectively. Also, the results suggest that the volume of drugs administered into the epidural space of pregnant sheep should be half the volume that would be used in non-pregnant sheep. 相似文献
10.
Florentino Carral San Laureano José Vicente Gutiérrez Manzanedo Carmen Ayala Ortega Concepción García Calzado Juan José Silva Rodríguez Manuel Aguilar Diosdado 《Endocrinología y nutrición》2010,57(6):268-276
Together with a balanced diet, regular physical activity is one of the pillars of diabetes mellitus (DM) management. Physical activity theoretically provides the same advantages in people with DM as in the general population and also has some beneficial effects in controlling metabolic factors, such as improving blood glucose levels and insulin sensitivity. In this article, we analyze the main clinical studies published to date that evaluate the impact of physical activity on metabolic control or the development of chronic complications in patients with type 1 diabetes mellitus. In conclusion, most of the evaluated studies show that regular physical activity favorably affects metabolic control in DM (or at least does not have adverse effects). However, there is insufficient information about the impact of physical activity on the development and progression of chronic complications. 相似文献