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91.
92.
The Polyborinae is the most diverse subfamily of the Falconidae in terms of both morphology and behaviour, and includes falconet‐shaped birds (Spiziapteryx), arboreal omnivores (Daptrius, Ibycter), as well as terrestrial generalists and scavengers (Caracara, Milvago and Phalcoboenus). The Polyborinae are endemic to the New World, with all but one species (Caracara cheriway) being restricted to Central and South America. Using over 7300 bp of mitochondrial and nuclear sequence data, we aim to clarify the taxonomy and biogeography of the Polyborinae. The genus Milvago was unexpectedly found to be polyphyletic, with Chimango Caracara Milvago chimango being related to the genus Phalcoboenus and Yellow‐headed Caracara Milvago chimachima being sister to Daptrius. Furthermore, very low genetic divergence was found among the four species of the genus Phalcoboenus, with the lowest divergence being between White‐throated Caracara Phalcoboenus albogularis and Mountain Caracara Phalcoboenus megalopterus. Our divergence time analyses revealed that the Polyborinae started to diversify in the Miocene, at about 14 Ma, and that the generalist/scavenger behaviour in the Falconidae appeared between 14 and 6.6 Ma. All speciation events within the caracaras occurred during the Pleistocene. This situation differs from the general pattern described for forest birds, in which most diversification events are older, occurring primarily in the Pliocene and Miocene. 相似文献
93.
The assessor performance is a key point in a sensory evaluation. In particular, at the end of a session, a decrease of the performance can be feared. We propose to analyze this performance with various criteria: usual ones as the main product effect or the error variance; a new one measuring the perceived products variability. The performance can then be studied all along the session from two points of view: in taking into account the only products tested at a given instant (named instantaneous); in taking into account all the products tested up to a given instant (named cumulative). In the presented example, in spite of the large number of products successively tested by each assessor, the instantaneous performance of the panel shows no significant deterioration. Furthermore, when the number of products tested by each assessor increases, more significant product effects can be obtained thanks to the accumulation of the amount of data. This shows that the number of products that can be reasonably studied by one assessor during one session is generally underestimated. 相似文献
94.
D Bellar A Hatchett LW Judge ME Breaux L Marcus 《Biology of sport / Institute of Sport》2015,32(4):315-320
CrossFit is becoming increasingly popular as a method to increase fitness and as a competitive sport in both the Unites States and Europe. However, little research on this mode of exercise has been performed to date. The purpose of the present investigation involving experienced CrossFit athletes and naïve healthy young men was to investigate the relationship of aerobic capacity and anaerobic power to performance in two representative CrossFit workouts: the first workout was 12 minutes in duration, and the second was based on the total time to complete the prescribed exercise. The participants were 32 healthy adult males, who were either naïve to CrossFit exercise or had competed in CrossFit competitions. Linear regression was undertaken to predict performance on the first workout (time) with age, group (naïve or CrossFit athlete), VO2max and anaerobic power, which were all significant predictors (p < 0.05) in the model. The second workout (repetitions), when examined similarly using regression, only resulted in CrossFit experience as a significant predictor (p < 0.05). The results of the study suggest that a history of participation in CrossFit competition is a key component of performance in CrossFit workouts which are representative of those performed in CrossFit, and that, in at least one these workouts, aerobic capacity and anaerobic power are associated with success. 相似文献
95.
Abstract Morphologically similar species occur in various groups of insects, including aphid pests. In Europe, Aphis frangulae Kaltenbach and Aphis gossypii Glover (sometimes considered as subspecies) are differentiated usually on the basis of life cycle and host plant. We used a sexual population of A. frangulae collected on the primary host and samples of A. gossypii collected on cucurbits or cotton for the development of molecular markers. DNA sequence data for the gene encoding cytochrome b and for the barcode region of cytochrome oxidase I, as well as a length polymorphism for an intron in the sodium channel para‐type gene discriminated unambiguously between the two taxa. These markers were also used as identification keys for aphids collected on crops belonging to the Solanaceae. The cytochrome b marker differentiates host‐related Aphis gossypii haplotypes, and the para‐type gene intron might be suitable for the resolution of taxonomic problems in other aphid species complexes. 相似文献
96.
97.
We have identified a protein in Chlamydomonas reinhardtii cell extracts that specifically binds the single-stranded (ss) Chlamydomonas G-strand telomere sequence (TTTTAGGG)n. This protein, called G-strand binding protein (GBP), binds DNA with two or more ss TTTTAGGG repeats. A single polypeptide (M(r) 34 kDa) in Chlamydomonas extracts binds (TTTTAGGG)n, and a cDNA encoding this G-strand binding protein was identified by its expression of a G-strand binding activity. The cDNA (GBP1) sequence predicts a protein product (Gbp1p) that includes two domains with extensive homology to RNA recognition motifs (RRMs) and a region rich in glycine, alanine and arginine. Antibody raised against a peptide within Gbp1p reacted with both the 34 kDa polypeptide and bound G-strand DNA-protein complexes in gel retardation assays, indicating that GBP1 encodes GBP. Unlike vertebrate heteronuclear ribonucleoproteins, GBP does not bind the cognate telomere RNA sequence UUUUAGGG in gel retardation, North-Western or competition assays. Thus, GBP is a new type of candidate telomere binding protein that binds, in vitro, to ss G-strand telomere DNA, the primer for telomerase, and has domains that have homology to RNA binding domains in other proteins. 相似文献
98.
Ustilago maydis, the causal agent of corn smut disease, displays dimorphic growth in which it alternates between a unicellular, nonpathogenic yeast-like form and a dikaryotic, pathogenic filamentous form. Previously, a constitutively filamentous haploid mutant was obtained. Complementation of this mutant led to the isolation of the gene encoding adenylate cyclase, uac1. Secondary mutagenesis of a uac1 disruption strain allowed the isolation of a large number of suppressor mutants, termed ubc, for Ustilago bypass of cyclase, lacking the filamentous phenotype. Analysis of one of these suppressor mutants previously led to the identification of the ubc1 gene, encoding the regulatory subunit of cAMP-dependent protein kinase. In this report we describe the isolation of cosmids containing three new ubc genes, termed ubc2, ubc3, and ubc4. We also describe the morphology of the ubc2, ubc3, and ubc4 mutants in a uac1- background as well as in a background with a functional uac1 gene. In addition, we describe several mutant strains not complemented with any of the genes currently in hand and that are thus presumed to possess mutations in additional ubc genes. Copyright 1998 Academic Press. 相似文献
99.
The taste of polycose in hamsters 总被引:2,自引:2,他引:0
Hamsters show a preference for Polycose, a mixture of starch-derived
glucose polymers, that is as strong as their preference for sucrose.
However, in the hamster, taste aversions to Polycose may be less easily
acquired than taste aversions to sucrose and the qualitative aspects of
Polycose are unknown in this species. In order to examine the taste of
Polycose in the hamster, we utilized a taste-aversion protocol with two
conditioning trials. Animals were trained to avoid one of three different
conditioning stimuli: 50 mM sucrose, 100 mM Polycose and a mixture of 50 mM
sucrose with 100 mM Polycose. Control animals were conditioned with
deionized water. After the second conditioning trial, generalization
testing began for the three conditioning stimuli plus 3 mM citric acid, 300
mM KCI and 30 mM NaCl. The results showed that aversions to Polycose,
sucrose or the Polycose/sucrose mixture cross- generalized, demonstrating
that Polycose and sucrose share a common taste percept in the hamster. None
of the aversions generalized to NaCl, citric acid or KCI. In addition,
comparisons among the patterns of taste generalizations indicated that the
tastes of Polycose and sucrose also had distinct qualitative components.
Finally, although the taste of 100 mM Polycose was more salient than the
taste of 50 mM sucrose, the taste of sucrose could still be detected in a
mixture with Polycose.
相似文献
100.
The 67-kDa laminin receptor originated from a ribosomal protein that acquired a dual function during evolution 总被引:8,自引:0,他引:8
Ardini E; Pesole G; Tagliabue E; Magnifico A; Castronovo V; Sobel ME; Colnaghi MI; Menard S 《Molecular biology and evolution》1998,15(8):1017-1025
The 67-kDa laminin receptor (67LR) is a nonintegrin cell surface receptor
that mediates high-affinity interactions between cells and laminin.
Overexpression of this protein in tumor cells has been related to tumor
invasion and metastasis. Thus far, only a full-length gene encoding a
37-kDa precursor protein (37LRP) has been isolated. The finding that the
cDNA for the 37LRP is virtually identical to a cDNA encoding the ribosomal
protein p40 has suggested that 37LRP is actually a component of the
translational machinery, with no laminin-binding activity. On the other
hand, a peptide of 20 amino acids deduced from the sequence of 37LR/p40 was
shown to exhibit high laminin-binding activity. The evolutionary
relationship between 23 sequences of 37LRP/p40 proteins was analyzed. This
phylogenetic analysis indicated that all of the protein sequences derive
from orthologous genes and that the 37LRP is indeed a ribosomal protein
that acquired the novel function of laminin receptor during evolution. The
evolutionary analysis of the sequence identified as the laminin-binding
site in the human protein suggested that the acquisition of the
laminin-binding capability is linked to the palindromic sequence LMWWML,
which appeared during evolution concomitantly with laminin.
相似文献