排序方式： 共有8条查询结果，搜索用时 25 毫秒
1
1.
Kutschera U 《Science (New York, N.Y.)》2006,311(5763):952-4; author reply 952-4
2.
Participation of phosphofructokinase,malate dehydrogenase and isocitrate dehydrogenase in capacitation and acrosome reaction of boar spermatozoa 
下载免费PDF全文
下载免费PDF全文 E Breininger D Dubois VE Pereyra PC Rodriguez MM Satorre PD Cetica 《Reproduction in domestic animals》2017,52(5):731-740
The aim of this work was to determine the enzymatic activity of phosphofructokinase (PFK), malate dehydrogenase (MDH) and isocitrate dehydrogenase (IDH) in boar spermatozoa and study their participation in bicarbonate‐induced capacitation and follicular fluid‐induced acrosome reaction. Enzymatic activity of these enzymes was determined spectrophotometrically in extracts of boar spermatozoa. Sperm suspensions were incubated in the presence of bicarbonate (40 mM), a well‐known capacitation inducer, or follicular fluid (30%), as an acrosome reaction inducer, and different concentrations of oxoglutarate, oxalomalate and hydroxymalonate, inhibitors of PFK, IDH and MDH, respectively. Capacitation percentages were determined by the fluorescence technique of chlortetracycline (CTC), and true acrosome reaction was determined by trypan blue and differential–interferential contrast, optical microscopy. The activity of PFK in boar spermatozoa enzymatic extracts was 1.70 ± 0.19 U/1010 spermatozoa, the activity of NAD‐ and NADP‐dependent IDH was 0.111 ± 0.005 U/1010 and 2.22 ± 0.14 U/1010 spermatozoa, respectively, and the activity of MDH was 4.24 ± 0.38 U/1010 spermatozoa. The addition of the specific inhibitors of these enzymes prevented sperm capacitation and decreased sperm motility during capacitation and inhibited the acrosome reaction (AR), without affecting the sperm motility during this process. Our results demonstrate the participation of PFK, IDH and MDH in bicarbonate‐induced capacitation and follicular fluid‐induced acrosome reaction in boar spermatozoa, contributing to elucidate the mechanisms that produce energy necessary for these processes in porcine spermatozoa. 相似文献
3.
Kutschera U 《Science (New York, N.Y.)》2008,321(5893):1157-1158
4.
The Influence of Maca (<Emphasis Type="Italic">Lepidium meyenii</Emphasis>) on Antioxidant Status,Lipid and Glucose Metabolism in Rat 总被引：1，自引：0，他引：1
Vecera R Orolin J Skottová N Kazdová L Oliyarnik O Ulrichová J Simánek V 《Plant foods for human nutrition (Dordrecht, Netherlands)》2007,62(2):59-63
This work focused on the effect of maca on lipid, anti-oxidative, and glucose parameters in hereditary hypertriglyceridemic
(HHTg) rat. Maca (1%) was administred to rats as a part of a high-sucrose diet (HSD) for 2 weeks. Rosiglitazone (0.02%) was
used as a positive control. Maca significantly decreased the levels of VLDL (very low density lipoproteins), LDL (low density
lipoproteins), and total cholesterol, and also the level of TAG (triacylglycerols) in the plasma, VLDL, and liver. Maca, as
well as rosiglitazone, significantly improved glucose tolerance, as the decrease of AUC (area under the curve) of glucose
showed, and lowered levels of glucose in blood. The activity of SOD (superoxide dismutase) in the liver, the GPX (glutathione
peroxidase) in the blood, and the level of GSH (glutathione) in liver increased in all cases significantly. Results demonstrate
that maca seems to be promising for a positive influence on chronic human diseases (characterized by atherogenous lipoprotein
profile, aggravated antioxidative status, and impaired glucose tolerance), and their prevention. 相似文献
5.
Henning W Bell WA Billquist PJ Glagola BG Kutschera W Liu Z Lucas HF Paul M Rehm KE Yntema JL 《Science (New York, N.Y.)》1987,236(4802):725-727
Calcium-41 has been suggested as a new tool for radiometric dating in the range of 10(5) to 10(6) years. The concentration of cosmogenic calcium-41 in natural samples of terrestrial origin has now been determined by high-sensitivity accelerator mass spectrometry after pre-enrichment in calcium-41 with an isotope separator. Ratios of calcium-41 to total calcium between 2 x 10(-14) and 3 x 10(-15) were measured for samples of contemporary bovine bone and from limestone deposits. Some prospects for the use of calcium-41 for dating Middle and Late Pleistocene bone and for other geophysical applications are discussed. 相似文献
6.
Hailer F Kutschera VE Hallström BM Klassert D Fain SR Leonard JA Arnason U Janke A 《Science (New York, N.Y.)》2012,336(6079):344-347
Recent studies have shown that the polar bear matriline (mitochondrial DNA) evolved from a brown bear lineage since the late Pleistocene, potentially indicating rapid speciation and adaption to arctic conditions. Here, we present a high-resolution data set from multiple independent loci across the nuclear genomes of a broad sample of polar, brown, and black bears. Bayesian coalescent analyses place polar bears outside the brown bear clade and date the divergence much earlier, in the middle Pleistocene, about 600 (338 to 934) thousand years ago. This provides more time for polar bear evolution and confirms previous suggestions that polar bears carry introgressed brown bear mitochondrial DNA due to past hybridization. Our results highlight that multilocus genomic analyses are crucial for an accurate understanding of evolutionary history. 相似文献
7.
Manning SW Ramsey CB Kutschera W Higham T Kromer B Steier P Wild EM 《Science (New York, N.Y.)》2006,312(5773):565-569
Radiocarbon (carbon-14) data from the Aegean Bronze Age 1700-1400 B.C. show that the Santorini (Thera) eruption must have occurred in the late 17th century B.C. By using carbon-14 dates from the surrounding region, cultural phases, and Bayesian statistical analysis, we established a chronology for the initial Aegean Late Bronze Age cultural phases (Late Minoan IA, IB, and II). This chronology contrasts with conventional archaeological dates and cultural synthesis: stretching out the Late Minoan IA, IB, and II phases by approximately 100 years and requiring reassessment of standard interpretations of associations between the Egyptian and Near Eastern historical dates and phases and those in the Aegean and Cyprus in the mid-second millennium B.C. 相似文献
8.
Kutschera U 《Science (New York, N.Y.)》2011,334(6061):1347; author reply 1347-1347; author reply 1348
1