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21.
In Drosophila pseudoobscura, the amylase (Amy) multigene family is
contained within a series of inversions, or gene arrangements, on the third
chromosome. The Standard (ST), Santa Cruz (SC), and Tree Line (TL)
inversions are central to the phylogeny of arrangements, and have clusters
of other arrangements derived from them. The gene arrangements belonging to
each of these three clusters have a characteristic number of Amy genes,
ranging from three in ST to two in SC to one in TL. This distribution
pattern can reflect a history of either duplications or deletions, although
the data available in the past did not permit a decision between these
alternatives. We provide unambiguous evidence that three Amy genes were
present before the divergence of the ST, SC, and TL arrangements. Thus, the
current status of the Amy multigene family is the result of deletions in
the TL and SC arrangements, which created three new pseudogenes: TL
Amy2-psi, TL Amy3-psi, and SC Amy3- psi. Analysis of pseudogene sequences
revealed that, in the SC and ST arrangements, pseudogene evolution has been
retarded, most likely due to the homogenization effect of gene conversion.
Finally, by determining the original copy number, we have reconstructed the
evolutionary history of the Amy multigene family and linked it with the
evolution of the central gene arrangements.
相似文献
22.
This study examines the effect of sheep and human follicular fluid on the in vitro maturation (IVM) of sheep follicular oocytes. Oocyte cumulus complexes recovered post mortem were matured for 24 to 26 h at 38.6 degrees C, 5% CO(2) in air, in TCM-199 bicarbonate medium supplemented with 20% fetal calf serum (FCS) and, where stated, with maturation hormones, including FSH (5.0 ug/ml), LH (5.0 ug/ml) and estradiol (1 ug/ml), or with sheep follicular fluid recovered from large (>5mm) or small (2 to 5mm) ovarian follicles post mortem, or with human periovular follicular fluid obtained during routine IVF procedures. The matured oocytes were then denuded, and their maturation stage and developmental capacity were assessed by in vitro fertilization (IVF) and culture (IVC). It was found that inclusion of sheep or human follicular fluid or hormone supplements in the IVM media more than doubled the number of oocytes completing maturation (FCS alone 33%, compared with 76.2% for maturation hormones, 84.2% for fluid from large and 69.6% for fluid from small sheep follicles and 82.6% for human follicular fluid), and significantly increased fertilization rates (FCS alone 51.6%, compared with 71.9% for maturation hormones, 78.4% for fluid from the large and 75.7% for fluid from small sheep follicles and 73.1% for human follicular fluid) without discernible adverse effects on the development of the cleaving embryos to the morula or blastocyst stage in culture. Omission of FCS and supplements from the IVM medium resulted in a marked reduction (56%) in the number of oocytes maturing. This reduction could be offset to a large part, but not completely, by inclusion of human follicular fluid or human follicular fluid plus LH (5 ug/ml) in the medium. The results of this study show that addition of sheep or human follicular fluid to maturation medium can enhance rather than inhibit the maturation and fertilizability of sheep follicular oocytes in vitro. 相似文献
23.
Abstract Bacitracin affinity chromatography has been used to purify proteinases of the parasitic protozoon Tritrichomonas foetus . It proved superior to other affinity chromatography methods we have tested for the purification of trichomonad proteinases and should prove a useful procedure for purifying cysteine proteines from these parasites and other parasitic protozoa. The main cysteine proteinases of T. foetus were purified over 100-fold to be free from the majority of other cell proteins. About 90 μg of protein containing 1.56-fold more proteinase activity than was detectable in the original cell lysate was obtained from 109 cells (7.2 mg protein). SDS-PAGE revealed that the eluate contained two main Coomassie blue-staining bands. N-terminal amino acid sequence analysis of these proteins confirmed that one of them was a cysteine proteinase with unusuall features. Cysteine proteinases were also purified from cell lysates of Trichomonas vaginalis and a N-terminal sequence determined. This is the first amino acid sequence information that has been obtained for trichomonad cysteine proteinases. The method was also used to purify proteinases from the medium of T. foetus cultures. Some selectivity in binding of the proteinases to the affinity column was found. 相似文献
24.
The application of sensory methodology for measuring deodorizing effect of an air conditioner equipped with electric plasma was introduced. Deodorizing effect was measured using chemical and sensory methods at different time (0, 30 and 60 min) and mode (control, blowing and cooling) of an air conditioner. Smoke from a roll of cigarette in a closed room was used as a source of odor and the concentrations of acetic acid and ammonia were measured as odorous chemical components. As one of the sensory methods triangle test was used and as a first step to obtain deodorizing effects by triangle test, the threshold of each panelist was obtained as the log dilution ratio of odor concentration at which the difference from odorless air was detected. The odor concentration at each time and mode was calculated using the threshold of the panel and the deodorizing effect was obtained on the basis of the odor concentration. In addition to a triangle test, scaling methods such as category scaling or magnitude estimation were used to measure deodorizing effect of an air conditioner. Deodorizing effects by scaling methods were calculated based on odor intensity with time at each mode. The regression analysis was done between the efficacy of deodorizing effect by sensory test and those by acetic acid and ammonia, the R2 values of the regression equations for triangle test, category scale, and magnitude estimation were 0.84, 0.72 and 0.69, respectively. Deodorizing effect by triangle test explained the decrease of acetic acid and ammonia better than those by category scaling or magnitude estimation while high cost and time consuming labor involved in triangle tests reduced the merit. The results of this study demonstrated that various sensory methods could be used to measure deodorizing effect of air conditioners and further researches on fast and reliable methods are needed to establish the official procedures. 相似文献
25.
FNR-DNA interactions at natural and semi-synthetic promoters 总被引:8,自引:1,他引:7
26.
27.
Bruce R. Mate Kelly A. Rossbach Sharon L. Nieukirk Randall S. Wells A. Blair Irvine Michael D. Scott Andrew J. Read 《Marine Mammal Science》1995,11(4):452-463
An adult, female bottlenose dolphin ( Tursiops trucncatus ) was radio tagged and monitored via satellite-based Argos receivers for 25 d from 28 June to 23 July 1990, in Tampa Bay, Florida. A total of 794 transmissions were obtained during 106 satellite passes. A mean of 3.9 (SE = 0.24) locations/day were determined by Service Argos and showed the animal remained in the bay, usually close to the southeastern shore. The dolphin moved at least 581 km at a minimum mean speed of 1.2 (SE = 0.1) km/h. Data from 63, 922 dives were recorded. The animal spent an average of 87.1 (SE = 0.6)% of the time submerged, with a mean dive duration of 25.8 (SE = 0.5) sec. Mean dive duration differed significantly between four periods of the day, as did the mean percent of time spent submerged. During the early morning the animal spent more time at the surface, averaged shorter dives, and was submerged less than other times of day. This is the first study to demonstrate die1 dive cycles in a bottlenose dolphin. Four months after tag loss, the dolphin was photographed with no evidence of necrosis or disfigurement of the dorsal fin. Satellite telemetry was demonstrated as an effective means of documenting the movements and dive behavior of a small inshore cetacean. 相似文献
28.
Inositol (1,4,5)trisphosphate-promoted Ca2+ release from microsomal fractions of rat liver 总被引:23,自引:0,他引:23
Crude mitochondrial fractions containing a substantial amount of microsomes accumulate Ca2+ in the presence of ATP, ruthenium red and oligomycin. A proportion of this accumulated Ca2+ is released by the addition of low concentrations (ca. 1 microM) of inositol (1,4,5) trisphosphate . Under some conditions the release is transient, and evidence is presented which suggests that this is due to inhomogeneity in the vesicle population. (1,4,5)inositol trisphosphate -induced Ca2+ release can also be demonstrated, under appropriate experimental conditions, in a more purified microsomal fraction essentially free of mitochondria. 相似文献
29.
The reaction of tri-O-acetyl-d-allal or -d-glucal, ethyl 4,6-di-O-acetyl-2,3-dideoxy-α-d)-erythro-hex-2-enopyranoside, or 1,4,6-tri-O-acetyl-α,β-d-erythro-hex-2-enopyranose with sodium azide in acetonitrile under catalysis by boron trifluoride diethyl etherate yields a mixture of 4,6-di-O-acetyl-3-azido-3-deoxy-d-allal and -d-glucal, together with both anomers of 4,6-di-O-acetyl-2,3-dideoxy-d-erythro-hex-2-enopyranosyl azide. The mechanism of these reactions is discussed. 3-Amino-3-deoxy-d-allal and -d-glucal and their derivatives are described. 相似文献
30.
The major pathway by which liver lysosomal enzymes degrade phosphatidylinositol is through an EDTA-insensitive formation of phosphorylinositol. This is in distinct contrast with the Ca2+-dependent production of phosphorylinositol from phosphatidylinositol, which is located in the cytosol. Lysosomal enzymes can also totally deacylate phosphatidylinositol, producing glycerophosphorylinositol. 相似文献