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561.
The aim of this study was to evaluate the influence of Hoechst 33342 (H‐42) concentration and of the male donor on the efficiency of sex‐sorting procedure in canine spermatozoa. Semen samples from six dogs (three ejaculates/dog) were diluted to 100 × 106 sperm/ml, split into four aliquots, stained with increasing H‐42 concentrations (5, 7.5, 10 and 12.5 μl, respectively) and sorted by flow cytometry. The rates of non‐viable (FDA+), oriented (OS) and selected spermatozoa (SS), as well as the average sorting rates (SR, sorted spermatozoa/s), were used to determine the sorting efficiency. The effects of the sorting procedure on the quality of sorted spermatozoa were evaluated in terms of total motility (TM), percentage of viable spermatozoa (spermatozoa with membrane and acrosomal integrity) and percentage of spermatozoa with reacted/damaged acrosomes. X‐ and Y‐chromosome‐bearing sperm populations were identified in all of the samples stained with 7.5, 10 and 12.5 μl of H‐42, while these two populations were only identified in 77.5% of samples stained with 5 μl. The values of OS, SS and SR were influenced by the male donor (p < 0.01) but not by the H‐42 concentration used. The quality of sorted sperm samples immediately after sorting was similar to that of fresh samples, while centrifugation resulted in significant reduction (p < 0.05) in TM and in the percentage of viable spermatozoa and a significant increase (p < 0.01) in the percentage of spermatozoa with damage/reacted acrosomes. In conclusion, the sex‐sorting of canine spermatozoa by flow cytometry can be performed successfully using H‐42 concentrations between 7.5 and 12.5 μl. The efficiency of the sorting procedure varies based on the dog from which the sperm sample derives.  相似文献   
562.
The following three articles have been published online as part of the EVE Oncology Virtual Issue which is available online at wileyonlinelibrary.com/journal/eve  相似文献   
563.
The atmospheric Cherenkov gamma-ray telescope MAGIC, designed for a low-energy threshold, has detected very-high-energy gamma rays from a giant flare of the distant Quasi-Stellar Radio Source (in short: radio quasar) 3C 279, at a distance of more than 5 billion light-years (a redshift of 0.536). No quasar has been observed previously in very-high-energy gamma radiation, and this is also the most distant object detected emitting gamma rays above 50 gigaelectron volts. Because high-energy gamma rays may be stopped by interacting with the diffuse background light in the universe, the observations by MAGIC imply a low amount for such light, consistent with that known from galaxy counts.  相似文献   
564.
Although there is evidence that liquids have flowed on the surface at Titan's equator in the past, to date, liquids have only been confirmed on the surface at polar latitudes, and the vast expanses of dunes that dominate Titan's equatorial regions require a predominantly arid climate. We report the detection by Cassini's Imaging Science Subsystem of a large low-latitude cloud system early in Titan's northern spring and extensive surface changes (spanning more than 500,000 square kilometers) in the wake of this storm. The changes are most consistent with widespread methane rainfall reaching the surface, which suggests that the dry channels observed at Titan's low latitudes are carved by seasonal precipitation.  相似文献   
565.
Ultraviolet images of Venus over a 3-month period show marked evolution of the planetary scale features in the cloud patterns. The dark horizontal Y feature recurs quasi-periodically, at intervals of about 4 days, but it has also been absent for periods of several weeks. Bow-shaped features observed in Pioneer Venus images are farther upstream from the subsolar point than those in Mariner 10 images.  相似文献   
566.
The distribution of seven flavonoids, eriocitrin, luteolin 3'-O-beta-d-glucuronide, hesperidin, diosmin, isoscutellarein 7-O-glucoside, hispidulin 7-O-glucoside, and genkwanin, has been studied in Rosmarinus officinalis leaves, flowers, stems, and roots during plant growth. The maximum level reached by luteolin 3'-O-beta-d-glucuronide in leaves during June-August suggests the existence of a delay between the activation of the enzymes involved in the flavanone and flavone biosynthesis. The presence of hesperidin and diosmin in the vascular system is significant, and hesperidin shows even higher levels than the phenolic diterpenes and rosmarinic acid. The distribution of flavonoids observed in R. officinalis suggests a functional and structural relationship between phytoregulators and flavonoids, where flavonoids would be "protectors" of the activity of phytoregulators. A hypothesis for the general pathway of biosynthesis of these compounds in plants of the family Labiatae is proposed.  相似文献   
567.
Tea is a complex mixture containing a range of compounds from simple phenolics to complex thearubigins, many of which have well-recognized antioxidant properties. This paper describes the application of high-performance liquid chromatography-mass spectrometry (HPLC-MS(n)) methods for the rapid and routine analysis of more than 30 phenolics in tea. Green and black tea infusions were injected directly onto a reversed phase HPLC column, and the phenolics eluted using two different mobile phase gradients, one optimized to resolve catechin derivatives and the other, flavonols and theaflavins. Compounds, identified on the basis of their retention time, absorbance spectrum, and MS fragmentation pattern, included (+)-catechin, (-)-epicatechin, theaflavin and their various gallate derivatives, quercetin and kaempferol mono-, di-, and triglycosides, quinic acid esters of gallic acid and hydroxycinnamates, and the purine alkaloids, caffeine and theobromine.  相似文献   
568.
To assess the protective effects of diphenylamine (DPA) on yield, DPA- and non-DPA-treated plants of potatoes (Solanum tuberosum cv. Agria) were exposed to ambient air at a rural site in Spain. Concentrations of ambient ozone were high at the site. Untreated plants served as controls. The DPA treatments did not have a significant effect on Chl content. The treatment with DPA (0.2 M) caused a significant increase of fresh weight production and tuber number of the potato plants in both years of study (32 and 47% in 2002 and 9 and 27% in 2003). Changes in the activity of antioxidant enzymes guaiacol peroxidase (GPX) and glutathione reductase (GR) in the leaves were determined in control and DPA-treated plants. The GPX activity in the leaves was significantly lower in the treated plants. GR was also lower, but not significantly, in the treated plants. The highest correlation between enzyme activity and yield was found in the case of GPX. The protective effect of DPA was related inversely to peroxidase activity. This is the first report demonstrating markedly enhanced yield and reduction of peroxides of potentially harmful O3 by DPA as a mechanism for protecting plants against noxious oxidative stress from the environment.  相似文献   
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