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An experimental study of the effect of air pollutants on health can be undertaken only subsequent to the creation of synthetically polluted atmosphere in exposure chambers as a readily available and easily controllable laboratory tool. The many and varied pollutants must be studied singly and in combination so as to reproduce any synergistic or antagonistic effects that may exist. A study of pollutant substances at their source is wholly inadequate in view of the pronounced photo-chemical activity in the atmosphere. The products of this activity may well be the significant ones insofar as morbid effects are concerned. In the acute and subacute biological studies, both in vitro and in vivo systems are being used with the experimental progression being from the simple to the complex. 相似文献
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Six polymorphic microsatellite loci were isolated and characterized from the temporary social parasitic ant Lasius fuliginosus by a highly efficient enrichment procedure. Observed allele numbers ranged from three to 20 per locus, whereby four out of the six tested loci had more than 10 alleles and showed both observed and expected heterozygosities greater than 70%. For each locus we present suitable primer sequences. With these microsatellite markers we will be able to reveal colony and population structure of L. fuliginosus. 相似文献
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MEREDIN STOLTENBERG PETER THERKILDSEN ARNE ANDREASEN KNUD B. JENSEN SOREN JUHL ERIK ERNST GORM DANSCHER 《The Histochemical journal》1998,30(4):237-244
A concept for the computer-assisted visualization of tubular organs is presented. Unmarked histological zinc-stained serial sections from the epididymis of the Wistar rat were aligned to demonstrate the concept. Virtual images were made through the aligned sections and served as controls for the alignment process. Animation of the serial sections and the virtual images revealed new information about the structure of the organ under investigation. The analysis was used to upgrade the anatomical knowledge of rat epididymis by describing how the epididymal duct runs through the structure. The proximal parts of the epididymis contain large communicating septa of connective tissue dividing the caput and the upper part of the corpus epididymidis into segments. The tortuousness was high in the caput with many turns within a small area of the epididymis, whereas longer loops were found in the lower part of the corpus and cauda epididymidis. The tube of the vas deferens was found to become an integrated part of the ductal system in the cauda epididymidis, although it was histologically easy to distinguish from the epididymal duct. The total number of cross-sections of the ductus epididymidis in the 2254, 15-mu m-thick, tissue sections analysed was 104 700, giving a minimum length of the ductal system of 1.5 m. © 1998 Chapman & Hall 相似文献
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The After-Effect of Water Stress on Transpiration Rate and Changes in Abscisic Acid Content of Young Wheat Plants 总被引:3,自引:0,他引:3
Young wheat plants (Triticum aestivum L. cv. Weibulls Starke II) were exposed to water stress for 1, 2 or 3 hours by cooling the roots. The plants were subjected to a constant water stress during the stress periods. By this treatment the leaf water potential was lowered from ?6.5 to ?11.5 bars. Leaf water potential, transpiration rate and abscisic acid content were determined during the stress periods and during the recovery. The water stressed plants showed an after-effect on transpiration rate lasting for between 10 and 24 hours depending on the duration of the stress. The amount of water stress in the stressed plants compared with the controls is defined as the difference in leaf water potential between the controls and the stressed plants during the stress period integrated over time. The amount of after-affect on transpiration is analogously defined as the difference in transpiration rate between the controls and the stressed plants during the recovery period integrated over time. There was a linear relationship between the amount of water stress and the amount of after-effect on transpiration of the leaves. The abscisic acid content of the leaves increased between 3.0 and 4.5 times the original content depending on the duration of the stress. However, during the recovery the abscisic acid content reattained the pre-stress level within 3 hours for all three stress periods. There was thus no direct relationship between the after-effect and the abscisic acid content of the leaf. 相似文献