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161.
Carey Krajewski Larry Buckley Patricia A. Woolley Michael Westerman 《Journal of Mammalian Evolution》1996,3(1):81-91
We report DNA sequence variation in 861 bp of the mitochondrial cytochromeb gene from 10 species of the dasyurid marsupial subfamily Phascogalinae (including the New Guinean genusMurexia) and an outgroup planigale (Planigale ingrami). Phylogenetic analyses of these sequences indicate that (1) the subfamily consists of three major clades corresponding to (a)Phascogale, (b) AustralianAntechinus, and (c) New Guinean Antechinus andMurexia; (2) Antechinus habbema constitutes the earliest branch of the New Guinean clade; and (3); Antechinus melanurus and A. naso are sister species within the New Guinean clade. Among Australian antechnuses,A. stuartii andA. swainsonii are more closely related to each other than either is toA. flavipes, a result that is seemingly at odds with all previous systematic studies. Although resolution is limited, it appears thatAntechnius andMurexia species form a clade to the exclusion ofPhascogale. This relationship suggests that male semelparity is not a strong synapomorphy for Australian antechinuses and phascogales, despite its apparent physiological similarity in the two groups.To whom correspondence should be addressed. 相似文献
162.
Angus R. Brown Maryanne Covington Robert C. Newton Robert Ramage Patricia Welch 《Journal of peptide science》1996,2(1):40-46
The affinity-based Nα-amino protecting group tetrabenzo [a,c,g,i]fluorenyl-17-methoxycarbonyl (Tbfmoc) has been utilized as a hydrophobic probe to allow the simple, quick and highly effective isolation of a 76 residue cysteine-containing protein (MCP-1). The base-labile Tbfmoc group can be removed under very mild conditions, which preserve the thiol-con taining protein in the reduced state. Oxidative folding was then used to furnish the biologically active β-chemokine MCP-1. 相似文献
163.
164.
In the moss Ceratodon purpureus a phytochrome gene encodes a phytochrome type (PhyCer) which has a C-terminal domain homologous to the catalytic domain of eukaryotic protein kinases (PKs). PhyCer exhibits sequence conservation to serine/ threonine as well to tyrosine kinases. Since PhyCer is expressed very weakly in moss cells, to investigate the proposed PK activity of PhyCer, we overexpressed PhyCer transiently in fibroblast cells. For this purpose we made a chimeric receptor, EC-R, which consists of the extracellular, the membrane-spanning and the juxtamembrane domains of the human epidermal growth-factor receptor (EGF-R) linked to the PK catalytic domain of PhyCer (CerKin). The expression of EC-R in transiently transfected cells was confirmed with antibodies directed against the extracellular domain of EGF-R or against CerKin. Both EGF-R and EC-R were immunoprecipitated from lysates of overexpressing cells with antibodies against the extracellular domain of EGF-R. Phosphorylation experiments were performed with the immunoprecipitates and the phosphorylation products were subjected to phosphoamino acid analysis. Phosphorylation products specifically obtained with EC-R-transfected cells exhibit phosphorylation on serine and threonine residues. In EC-R transfected cells the endogenous EGF-R showed enhanced phosphorylation of serine and threonine residues compared to EGF-R immuno-precipitated from control cells. Although CerKin is closest to the catalytic domain of a protein tyrosine kinase from Dictyostelium discoideum, EC-R does not appear to phosphorylate tyrosine residues in vitro. From our data we conclude that PhyCer carries an active PK domain capable of phosphorylating serine and threonine residues.Abbreviations CerKin
protein kinase catalytic domain of PhyCer
- EC-R
chimeric receptor consisting of the extracellular, the membrane spanning and the juxtamembrane domains of the human epidermal growth factor receptor (EGF-R) linked to the protein kinase catalytic domain of PhyCer
- EGF-R
epidermal growth factor receptor
- mAb
monoclonal antibody
- PhyCer
phytochrome gene in Ceratodon encoding a phytochrome type which has a C-terminal domain homologous to the catalytic domain of eucaryotic protein kinases
- PK
protein kinase
- PVDF
polyvinyl difluoride
- Ser
serine
- Thr
threonine
- Tyr
tyrosine
Dr. Patricia Algarra was supported by the Alexander von Humboldt Foundation, Germany. This work was supported by the Deutsche Forschungsgemeinschaft (DFG), Bonn, Germany. 相似文献
165.
166.
Patricia C. Wright 《International journal of primatology》1995,16(5):835-854
I conducted the first long- term study of the life history patterns of Propithecus diadema edwardsi—Milne- Edward’s sifaka— in the rain forests of southeastern Madagascar, beginning in 1986. I report behavioral observations
on a total of 33 individuals from three groups over a 9- year span. We captured,marked, and released 21 individuals. Individual group size ranged from three to nine sifakas. Two breeding females lived in
groups I and II until 1993. A newly formed group (III) had one breeding female. Age at first reproduction is 4 years for females
and 5 years for males. Gestation length is 179 days (n =2). Most births occurred in June (n = 17), but infants were also born in May (n = 2) and July (n =2). Nine of 21 (43%) infants born died before the age of 1 year, and 15 (67%) died before the age of reproduction. One female
bred in her natal group after the death of the resident male and the immigration of an adult male. Another two females disappeared
at 4 and 5 years of age;they could have emigrated or died. All 5- to- 6- year- old males (n = 4) have emigrated from their natal groups to adjacent
groups. Two have committed infanticide. Five or more individuals were killed by Cryptoprocta ferox.Despite high mortality and offspring dispersal, the number of individuals in the two main groups remained nearly the same
over the 9- year study. 相似文献
167.
168.
Delhon Patricia; Gojon Alain; Tillard Pascal; Passama Lucien 《Journal of experimental botany》1995,46(10):1585-1594
The effect of light on NO3 utilization was investigatedin non-nodulated soybean (Clycine max L. Merr., cv. Kingsoy)plants during a 14/10 h light/dark period at a constant temperatureof 26C. A 3050% decrease of net NO3 uptake ratewas observed 26 h after the lights were turned off. Thiswas specifically due to an inhibition of NO3 influx asmeasured by 15N incorporation during 5 min. The absolute valuesof NO3 efflux depended on whether the labelling protocolinvolved manipulation of the plants or not, but were not affectedby illumination of the shoots. Darkness had an even more markedeffect in lowering the reduction of 15NO3 in both rootsand shoots, as well as xylem transport of 15NO3 and reduced15N. Concurrently with this slowing down of transport and metabolicprocesses, accumulations of NO3 and Asn were significantlystimulated in roots during the dark period. These data are discussedin view of the hypothesis that darkness adversely affects NO3uptake through specific feedback control, in response to alterationsin the later steps of N utilization which are more directlydependent on light. Key words: Glycine max, light/dark cycles, nitrate uptake, nitrate reduction 相似文献
169.
Sergio Vidal Matilde Lombardero Pablo Sánchez Albina Román Lucas Moya 《The Histochemical journal》1995,27(3):204-209
Summary A simple procedure is described for removing Epon resin from semi-thin 1 m sections, which permits excellent postembedding immunohistochemical staining (avidin-biotin complex technique). The procedure was developed for the detection of growth hormone and prolactin in bovine adenohypophysis fixed with 2% paraformaldehyde and 0.5% glutaraldehyde in 0.1 m sodium cacodylate buffer pH 7.4–7.6. The results indicate that the removal of the epoxy embedding medium prior to the application of the immunohistochemical reagents was essential for the successful localization of the antigenic determinants of the two hormones. The immunocytochemical reactivity was obtained only after treating the sections with a solution of potassium hydroxide in a mixture of absolute methyl alcohol and propylene oxide (Maxwell's solution). An enhanced immunoreactivity was obtained when this treatment was followed by an additional treatment with either 4% hydrogen peroxide or a saturated aqueous solution of sodium metaperiodate. Because of the easy preparation of the Epon removal solution and the good structural preservation without damage to the antigenic determinants, Maxwell's solution is suggested as a good etching agent which can be used in immunohistochemical studies on semi-thin sections with excellent results. 相似文献
170.
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