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61.
Comparative chromosome painting between two marsupials: origins of an XX/XY1Y2 sex chromosome system
Roland Toder Rachel J. W. O’Neill Johannes Wienberg Patricia C. M. O’Brien Lucille Voullaire Jennifer A. Marshall-Graves 《Mammalian genome》1997,8(6):418-422
Cross-species chromosome painting was used to investigate genome rearrangements between tammar wallaby Macropus eugenii (2n = 16) and the swamp wallaby Wallabia bicolor (2n = 10♀/11♂), which diverged about 6 million years ago. The swamp wallaby has an XX female:XY1Y2 male sex chromosome system thought to have resulted from a fusion between an autosome and the small original X, not involving
the Y. Thus, the small Y1 should represent the original Y and the large Y2 the original autosome. DNA paints were prepared from flow-sorted and microdissected chromosomes from the tammar wallaby.
Painting swamp wallaby spreads with each tammar chromosome-specific probe gave extremely strong and clear signals in single-,
two-, and three-color FISH. These showed that two tammar wallaby autosomes are represented unchanged in the swamp wallaby,
two are represented by different centric fusions, and one by a tandem fusion to make the very long arms of swamp wallaby Chromosome
(Chr) 1. The large swamp wallaby X comprises the tammar X as its short arm, and a tandemly fused 7 and 2 as the long arm.
The acrocentric swamp wallaby Y2 is a 2/7 fusion, homologous with the long arm of the X. The small swamp wallaby Y1 is confirmed as the original Y by its painting with the tammar Y. However, the presence of sequences shared between the microdissected
tammar Xp and Y on the swamp wallaby Y2 implies that the formation of the compound sex chromosomes involved addition of autosome(s) to both the original X and Y.
We propose that this involved fusion with an ancient pseudoautosomal region followed by fission proximal to this shared region.
Received: 16 October 1996/Accepted: 30 January 1997 相似文献
62.
Sorichter Stephan; Mair Johannes; Koller Arnold; Gebert Walter; Rama Daniel; Calzolari Charles; Artner-Dworzak Erika; Puschendorf Bernd 《Journal of applied physiology》1997,83(4):1076-1082
Sorichter, Stephan, Johannes Mair, Arnold Koller, WalterGebert, Daniel Rama, Charles Calzolari, Erika Artner-Dworzak, and BerndPuschendorf. Skeletal troponin I as a marker of exercise-inducedmuscle damage. J. Appl. Physiol.83(4): 1076-1082, 1997.The utility of skeletal troponin I (sTnI)as a plasma marker of skeletal muscle damage after exercise wascompared against creatine kinase (CK), myoglobin (Mb), and myosin heavychain (MHC) fragments. These markers were serially measured in normalphysical education teacher trainees after four different exerciseregimens: 20 min of level or downhill (16% decline) running(intensity: 70% maximal O2uptake), high-force eccentric contractions (70 repetitions), orhigh-force isokinetic concentric contractions of the quadriceps group(40 repetitions). Eccentrically biased exercise (downhill running andeccentric contractions) promoted greater increases in all parameters.The highest plasma concentration were found after downhill running{median peaks: 309 U/l CK concentration ([CK])}, 466 µg/l Mb concentration([Mb]), 1,021 µU/l MHC concentration ([MHC]),and 27.3 µg/l sTnI concentration ([sTnI]). Level running produced a moderate response (median peaks: 178 U/l [CK],98 µg/l [Mb], 501 µU/l [MHC], and 6.6 µg/l [sTnI]), whereas the concentric contraction protocoldid not elicit significant changes in any of the markers assayed. sTnIincreased and peaked in parallel to CK and stayed elevated (>2.2µg/l) for at least 1-2 days after exercise. In contrast to MHC,sTnI is an initial, specific marker of exercise-induced muscle injury,which may be partly explained by their different intracellularcompartmentation with essentially no (MHC <0.1%) or a small solublepool (sTnI: median 3.4%). 相似文献
63.
A freshwater sediment from a ditch of a peat grassland near Zegveld (Province of Utrecht, The Netherlands) was investigated for its potential methanogenic and syntrophic activity and the influence of sulfate and nitrate on these potential activities. Methanogenesis started after a 10 days lagphase. After 35–40 days aceticlastic methanogens were sufficiently enriched to cause a net decrease of acetate. In the presence of sulfate methane formation was only slightly affected. The addition of nitrate led to an outcompetion of aceticlastic methanogens by nitrate reducers. When inorganic electron acceptors were absent, substrates like propionate and butyrate were converted by syntrophic methanogenic consortia. Addition of inorganic electron acceptors resulted in an outcompetition of the syntrophic propionate and butyrate degrading consortia by the sulfate and nitrate reducers. 相似文献
64.
Summary A protocol for obtaining regenerated fertile plants from mesophyll protoplasts of three lines of Matthiola incana is described. Protoplasts were isolated from leaves of 21–28 days old Matthiola plants grown in controlled environment. Sustained divisions were achieved when protoplasts were embedded in sodium alginate. Up to 2.0 % of the protoplasts developed into colonies which could be transferred to shoot regeneration media. More than 25 % of the obtained calluses regenerated shoots. About 4 % of these shoots could be rooted and after transfer to soil phenotypically normal plants have been obtained.Abbreviations 2,4-D
2,4-dichlorphenoxyacetic acid
- NAA
naphthalene acetic acid
- IAA
indole-3-acetic acid
- BAP
6-banzylaminopurine
- IPA
isopentenyladenine
- IPAR
isopentenyladenosine
- MES
(2-[N-morpholino]) ethanesulfonic acid 相似文献
65.
66.
67.
Jos C. F. M. Dreesen Joep P. M. Geraedts John C. M. Dumoulin Johannes L. H. Evers Math H. E. C. Pieters 《Human genetics》1995,96(3):323-329
In order to approach preimplantation testing for the fragile-X syndrome, we used genotyping of the polymorphic RS46(DXS548) locus closely linked to the FMR1 gene, in single reproductive cells of females. The RS46(DXS548) amplification was adjusted to the single cell level by a two-round polymerase chain reaction (PCR) procedure. Unfertilized oocytes and extruded polar bodies were subjected to PCR. RS46(DXS548) genotyping at the single cell level was successful in 95% of the samples. In two-third of the metaphase II oocytes and first polar bodies obtained from women who were heterozygous at the RS46(DXS548) locus, both maternal RS46(DXS548) alleles were observed because of crossing over during the first meiotic division. This makes gamete selection by first polar body analysis inefficient. From the allele frequencies found in 56 unrelated individuals, a heterozygote frequency of 51% was estimated, whereas the observed heterozygote frequency was 56%. The whole PCR procedure can be performed within 16 h after blastomere biopsy. Consequently, the selection and transfer of the diagnosed embryos can be carried out within an acceptable time. Therefore, preimplantation testing for the fragile-X syndrome with the RS46(DXS548) AC-repeat may be an alternative choice for prenatal testing for those carrier females who are heterozygous (informative) at the RS46(DXS548) locus. 相似文献
68.
Johannes E. Philipp 《Radiation and environmental biophysics》1984,23(4):295-297
Summary In the above mentioned article [1] the notion of a time-dependent Gibbs free energy has been introduced to explain the observed time-pattern of embryo growth in seeds. Furthermore, the notion of a non-random thermal communication has been inferred from an inspection of the shapes of germination time distributions. It can be shown, however, that the reasoning leading to the time-dependent thermodynamic potential is based on inappropriate interpretation of kinetic equations, and that the shape of the distributions of germination time might be a natural consequence of the initial distribution of embryo size in the seeds.Discussion about the Paper Seed Germination as a Thermobiological Problem by L. G. Labouriau Radiation and Environmental Biophysics 15:345–366 (1978) 相似文献
69.
Reproductive strategies of coastal marine fishes in the tropics 总被引:14,自引:0,他引:14
Robert E. Johannes 《Environmental Biology of Fishes》1978,3(1):65-84
Synopsis A synthesis of ethnobiological, behavioral and physical oceanographic information leads to the conclusion that temperate zone models of reproductive strategy are inapplicable to many fishes of the coastal tropics. Intense predation appears to exert heavy selection pressure on fishes that spend their adult lives in coral, mangrove or tropical seagrass communities. Many exhibit spawning behaviors and spawn at times and locations that favor the transport of their pelagic eggs and pelagic larvae offshore where predation is reduced. This creates a countervailing selection pressure — the need to return the larvae to shallow water once they are ready to colonize their post-larval habitats. Accordingly, spawning is often concentrated at times of the year when prevailing winds or currents are at their weakest, thereby reducing the transport of larvae long distances from where they originated. Spawning is also concentrated in the vicinity of nearshore gyres which similarly favor the ultimate return of the larvae to their natal area. Among these species, therefore, offshore larval dispersal does not seem to be an adaptation for dispersal of the species, but rather an evolutionary response to intense predation pressure in the adult habitats. Lunar reproductive periodicity is more common among these species than has previously been recognized, and is one of the strategies employed to enhance the offshore flushing of eggs and larvae.This paper forms part of the proceedings of a mini-symposium convened at Cornell University, Ithaca, N. Y. 18–19 May 1976, entitled Patterns of Community Structure in Fishes (G. S. Helfman, ed.).Contribution No. 524, Hawaii Institute of Marine Biology, University of Hawaii, Honolulu. 相似文献
70.
Distribution of testosterone-estradiol binding globulin (TeBG) in the higher vertebrates 总被引:1,自引:0,他引:1
The presence of testosterone-estradiol binding globulin (TeBG) in a variety of higher vertebrate species has been investigated by an ammonium sulphate precipitation technique. TeBG has been demonstrated in significant amounts in primates, carnivora, marsupiala, and some artiodactyla, even in circumstances where previously electrophoretic studies failed to identify it. For the first time it has also been shown in trace amounts in certain rodents and birds. TeBG in the kangaroo substantiates the primitiveness of the protein in the mammal line and its absence in certain orders and species of eutherian mammals must represent a secondary loss. 相似文献