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951.
Whitlock R Hipperson H Mannarelli M Butlin RK Burke T 《Molecular ecology resources》2008,8(4):725-735
Amplified fragment length polymorphism (AFLP) fingerprint data are now commonly collected using DNA sequencers. AFLP genotypes are still often scored by eye from such data - a time-consuming, error-prone and subjective process. We present a semi-automated method of genotyping sequencer-collected AFLPs at predefined fragment locations (loci) within the fingerprint. Our method uses thresholds of AFLP-polymerase chain reaction-product fluorescence intensity (peak height) in order to: (i) exclude AFLP loci that are likely to contribute high rates of error to data sets, and (ii) determine the AFLP phenotype (fragment presence or absence) at the retained loci. Error rate analysis is an integral part of this process and is used to determine optimal thresholds that minimize genotyping error, while maximizing the numbers of retained loci. We show that application of this method to a large AFLP data set allows genotype calls that are rapid, objective and repeatable, facilitating the extraction of reliable genotype data for molecular ecological studies. 相似文献
952.
In this article, we describe an 8- to 10-day inquiry safari designed for middle/high school students to investigate hominid
evolution using replica skulls of extant and extinct vertebrates. Students begin the unit using their own skulls and proceed
to use the replica skulls of extant vertebrates to construct an understanding of how skulls can be used to interpret and infer
diets, dentition, dental formulae, bipedal or quadrupedal locomotion, and the social structure of animals. They are then able
to use this knowledge to construct similar inferences for extinct fossil hominids. Using radiometric dating data, the students
develop possible phylogenetic pathways for hominid evolution. The lessons promote the use of inquiry skills including journaling,
observing, drawing, puzzle-making, using taxonomic keys, and investigating into deep geological time. 相似文献
953.
Toivonen T Toivo T Pitkäaho R Puranen L Silfverhuth M Mennander A Hannula M Hyttinen J Jokela K 《Bioelectromagnetics》2008,29(5):363-370
The aim of this study was a dosimetrical analysis of the setup used in the exposure of the heads of domestic pigs to GSM-modulated radio frequency electromagnetic fields (RF-EMF) at 900 MHz. The heads of pigs were irradiated with a half wave dipole using three different exposure routines; short bursts of 1-3 s at two different exposure levels and a continuous 10-min exposure. The electroencephalogram (EEG) was registered continuously during the exposures to search for RF-EMF originated changes. The dosimetry was based on simulations with the anatomical heterogeneous numerical model of the pig head. The simulation results were validated by experimental measurements with the exposure dipole and a homogeneous liquid phantom resembling the pig head. The specific absorption rate (SAR), defined as a maximum average over 10 g tissue mass (SAR(10g)), was 7.3 W/kg for the first set of short bursts and 31 W/kg for the second set of short bursts. The SAR(10g) in the continuous 10-min exposure was 31 W/kg. The estimated uncertainty for the dosimetry was +/-25% (K = 2). 相似文献
954.
Biosynthesis and secretion of salusin-alpha from human cells 总被引:1,自引:0,他引:1
Salusins originally identified using bioinformatics analyses have been shown to act on the cardiovascular and endocrine systems. Although the hypotensive activity of salusin-alpha is limited, it exerts a significant anti-atherosclerotic effect via suppression of foam cell formation in human monocyte-derived macrophages by down-regulating acyl-CoA:cholesterol acyltransferase-1. Furthermore, serum salusin-alpha levels show a close negative correlation with the severity of atherosclerotic diseases. However, biosynthesis and secretion of salusin-alpha peptide from cultured mammalian cells have not been demonstrated to date. We examined the expression, synthesis and release of salusin-alpha in human-derived cell lines. Preprosalusin mRNA and protein were detected ubiquitously in all cells tested, whereas the processing of preprosalusin into salusin-alpha peptide is dependent upon each cell type. Immunohistochemical study revealed the most abundant salusin-alpha-like immunoreactivity to be present in HeLa cells which released salusin-alpha-like immunoreactivity into the culture supernatant. Analysis of extracted conditioned media from HeLa cells by reverse-phase high performance liquid chromatography coupled with radioimmunoassay detection revealed a single immunoreactive component that co-eluted with authentic salusin-alpha. These results present the first evidence that salusin-alpha is biosynthesized and released from human-derived cells. 相似文献
955.
Ripper D Schwarz H Stierhof YD 《Biology of the cell / under the auspices of the European Cell Biology Organization》2008,100(2):109-123
BACKGROUND INFORMATION: Electron microscopic immunolabelling of ultrathin thawed cryo-sections, according to the method of Tokuyasu, is widely used as a very sensitive high-resolution localization technique. Its main advantages are that antigens remain in a hydrated environment prior to immunolabelling, and that antigen accessibility is improved compared with resin section labelling. However, the quality of structural appearance and antigenicity depends highly on the limitations of the initial conventional chemical fixation step, such as slow diffusion and selective reaction/cross-linking of fixative molecules. RESULTS AND CONCLUSIONS: Cryofixation, instead of conventional chemical fixation, followed by freeze-substitution/chemical fixation, rehydration and further processing for Tokuyasu cryo-sectioning leads to an improved preservation of both ultrastructure and antigenicity. This is especially true for tissues which are difficult to preserve by conventional chemical fixation at ambient temperatures, such as plant material, Drosophila embryos or nematode tissue. In particular labile and highly dynamic structures (for example, microtubules and Golgi apparatus) are remarkably better preserved. These improvements are also valid for light microscopic applications. 相似文献
956.
957.
The reasons for the decline in net CO2 assimilation ( A ) above its thermal optimum are controversial. We tested the hypothesis that increasing the ratio of Rubisco activase to Rubisco catalytic site concentration would increase the activation state of Rubisco at high temperatures. We measured photosynthetic gas exchange, in vivo electron transport ( J ) and the activation state of Rubisco between 15 and 45 °C, at 38 and 76 Pa ambient CO2 , in wild-type (WT) and anti- rbc S tobacco. The Rubisco content of the anti- rbc S lines was 30% (S7-1) or 6% (S7-2) of WT, but activase levels were the same in the three genotypes. Anti- rbc S plants had lower A than WT at all temperatures, but had a similar thermal optimum for photosynthesis as WT at both CO2 levels. In WT plants, Rubisco was fully activated at 32 °C, but the activation state declined to 64% at 42 °C. By contrast, the activation state of Rubisco was above 90% in the S7-1 line, between 15 and 42 °C. Both A and J declined about 20% from T opt to the highest measurement temperatures in WT and the S7-1 line, but this was fully reversed after a 20 min recovery at 35 °C. At 76 Pa CO2 , predicted rates of RuBP regeneration-limited photosynthesis corresponded with measured A in WT tobacco at all temperatures, and in S7-1 tobacco above 40 °C. Our observations are consistent with the hypothesis that the high temperature decline in A in the WT is because of an RuBP regeneration limitation, rather than the capacity of Rubisco activase to maintain high Rubisco activation state. 相似文献
958.
Amelioration of cadmium-induced cardiac impairment by taurine 总被引:1,自引:0,他引:1
The present study has been designed to investigate the protective role of taurine (2-aminoethanesulfonic acid), a sulfur containing conditionally essential amino acid, against cadmium-induced cardiac dysfunction in mice. Cadmium chloride (CdCl(2)) was used as the source of cadmium and it was administered orally at a dose of 4mg/kg body weight for 6 days. Cadmium exposure caused significant accumulation of the cadmium and iron in mice hearts tissue. Levels of serum specific markers related to cardiac impairments, e.g. total cholesterol, HDL cholesterol and triglyceride were altered due to cadmium toxicity. Reduction in the activities of antioxidant enzymes, namely, superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST), glutathione reductase (GR), glutathione peroxidase (GPx) and glucose-6-phosphate dehydrogenase (G6PD) have been observed in cadmium exposed mice. Cadmium intoxication also decreased the cardiac glutathione (GSH) and total thiols contents and increased the levels of oxidized glutathione (GSSG), lipid peroxidation end products, protein carbonyl content and the extent of DNA fragmentation. Oral administration of taurine at a dose of 100mg/kg body weight for 5 days, however, prevented all the toxin-induced oxidative impairments mentioned above. "Ferric Reducing/Antioxidant Power (FRAP) assay" showed that taurine could protect the cardiac tissue by preventing cadmium-induced reduction of the intracellular antioxidant power. Histological examination of cardiac segments also supported the beneficial role of taurine against cadmium-induced damages in the murine hearts. Effect of a well established antioxidant, vitamin C has been included in the study as a positive control. Combining all, results suggest that taurine attenuates cadmium-induced impairment in mice hearts. 相似文献
959.
The isoprenoid metabolic pathway in protozoa of the Leishmania genus exhibits distinctive characteristics. These parasites, as well as other members of the Trypanosomatidae family, synthesize ergosterol, instead of cholesterol, as the main membrane sterol lipid. Leishmania has been shown to utilize leucine, instead of acetate as the main precursor for sterol biosynthesis. While mammalian dolichols are molecules containing 15-23 isoprene units, Leishmania amazonensis promastigotes synthesize dolichol of 11 and 12 units. In this paper, we show that the intracellular stages of L. amazonensis, amastigotes, synthesize mainly polyprenols of 9 isoprene units, instead of dolichol. 相似文献
960.
Jin S Umemoto E Tanaka T Shimomura Y Tohya K Kunizawa K Yang BG Jang MH Hirata T Miyasaka M 《FEBS letters》2008,582(20):3018-3024
Nepmucin/CLM-9 is an Ig domain-containing sialomucin expressed in vascular endothelial cells. Here we show that, like CD31, nepmucin was localized to interendothelial contacts and to vesicle-like structures along the cell border and underwent intracellular recycling. Functional analyses showed that nepmucin mediated homotypic and heterotypic cell adhesion via its Ig domain. Nepmucin-expressing endothelial cells showed enhanced lymphocyte transendothelial migration (TEM), which was abrogated by anti-nepmucin mAbs that block either homophilic or heterophilic binding. Notably, the mAbs that inhibited homophilic binding blocked TEM without affecting lymphocyte adhesion. These results suggest that endothelial nepmucin promotes lymphocyte TEM using multiple adhesion pathways. 相似文献