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61.
Pig to human xenotransplantation is considered a possible solution to the
prevailing chronic lack of human donor organs for allotransplantation. The
Galalpha1,3Gal determinant is the major porcine xenogeneic epitope causing
hyperacute rejection following human antibody binding and complement
activation. In order to characterize the tissue distribution of
Galalpha1,3Gal-containing and blood group- type glycosphingolipids in pig,
acid and nonacid glycosphingolipids were isolated from the kidney, small
intestine, spleen, salivary gland, liver, and heart of a single pig
obtained from a semi-inbred strain homozygous at the SLA locus. Glycolipids
were analyzed by thin-layer immunostaining using monoclonal antibodies, and
following ceramide glycanase cleavage as permethylated oligosaccharides by
gas chromatography, gas chromatography-mass spectrometry, and matrix-
assisted laser desorption/ionization mass spectrometry. The kidney
contained large amounts of Galalpha1,3Gal-containing penta- and
hexasaccharides having carbohydrate sequences consistent with the
Galalpha1,3nLc4and Galalpha1,3Lexstructures, respectively. The former
structure was tentatively identified in all organs by GC/MS. The presence
of extended Galalpha1,3Gal-terminated structures in the kidney and heart
was suggested by antibody binding, and GC/MS indicated the presence of a
Galalpha1,3nLc6structure in the heart. The kidney, spleen, and heart
contained blood group H pentaglycosylceramides based on type 1 (H-5-1) and
type 2 (H-5-2) chains, and H hexaglycosylceramides based on the type 4
chain (H-6-4). In the intestine H-5-1 and H-6-4 were expressed, in the
salivary gland H-5-1 and H-5-2, whereas only the H-5-1 structure was
identified in the liver. Blood group A structures were identified in the
salivary gland and the heart by antibody binding and GC/MS, indicating an
organ- specific expression of blood group AH antigens in the pig.
相似文献
62.
63.
Ecological imagery among the Upper Amazonian Canelos Quichua native peoples of eastern Ecuador provides a paradigmatic, symbolic template organized by sets of cosmological premises. This template, anchored by traditional shamanism and ceramic manufacture, is invoked in emotionally charged ceremonial and juropolitical contexts to express resistance to normative culture bearers who have a potential or real impact on the ecosystem and indigenous political economy. The imagery is described as it exists within a system of radical change. Mechanisms are discussed whereby ecosystem knowledge and social structure are systemically linked to cosmological premises within a dynamic system of indigenous cultural adaptability . [Ecuador, symbolism of Canelos Quichua, Amazonian cosmology, cultural adaptability, ecological imagery] 相似文献
64.
W. K. Whitten 《In vitro cellular & developmental biology. Plant》1979,15(1):19-22
Summary The genetic background and morphology of spontaneous mosaic hermaphrodites of mice have been described.
Presented in the formal symposium on Sexual Differentiation in Vitro and in Vivo at the 29th Annual Meeting of the Tissue
Culture Association, Denver, Colorado, June 4–8. 1978.
This work was supported by Grant HD 04083 from the National Institute of Child Health and Human Development. 相似文献
65.
Female sifaka mate selectively with one or more resident and/or non-resident males during the breeding season. Various adaptive explanations have been advanced to explain why female primates mate with multiple males including that 1) females seek to confuse paternity and thereby forestall male infanticide and/or ensure male infant care or 2) females seek to ensure fertilization. Assessing the power of fertilization insurance to explain mating patterns in females requires information on the temporal relationship between mating and ovarian hormones. The hormonal correlates of reproduction and mating in free-ranging Propithecus verreauxi were investigated using excreted steroids as indices of reproductive state. Solid-phase extraction and radioimmunoassay techniques were used to measure unconjugated estradiol (E3) and progesterone (P4) in 485 desiccated fecal samples collected from five female sifaka before and during the breeding season at Beza Mahafaly, Madagascar. Results suggest that behavioral estrus was characterized by 10- to 15-day elevations in E2; hormonal activity was observed to be similar to pseudo-estrus reported for other lemur species; apparent conception was associated with sustained P4 elevations beginning 1 to 3 days post-estrus with gestational phase elevations of E2 beginning 42 to 45 days post-conception; and mating with multiple partners appeared not to be a prerequisite to fertilization, as conception resulted from both monoandrous and polyandrous matings. These preliminary data suggest that fertilization insurance is not adequate to explain polyandrous mating in sifaka at Beza Mahafaly. © 1996 Wiley-Liss, Inc. 相似文献
66.
Patricia L. Whitten Ronda Stavisky Filippo Aureli Elizabeth Russell 《American journal of primatology》1998,44(1):57-69
This study examined whether fecal cortisol could be used as an index of stress responses. The stress responsiveness of fecal cortisol was tested with a stressor known to stimulate adrenal activity, the stress of anesthesia. Daily fecal and urine samples were collected from four captive chimpanzees (Pan troglodytes) before and after anesthetizations with Telazol®/Ketasat®. Tests of assay validity indicated that cortisol was measurable in chimpanzee fecal extracts. Fecal cortisol concentrations were significantly elevated 2 days after anesthetization, with elevations in seven of the eight treatments. The posttreatment peak was significantly greater than baseline values in three of the four subjects. Both fecal concentrations and proportionate increases in response to stress were significantly correlated with the corresponding values in urinary cortisol, confirming the stressfulness of these procedures and the stress responsiveness of fecal cortisol. These findings provide evidence for the application of fecal cortisol as a noninvasive index of physiologic stress in nonhuman primates. Am. J. Primatol. 44:57–69, 1998. © 1998 Wiley-Liss, Inc. 相似文献
67.
68.
Background and Aims Within Oncidiinae, there are severalgroups of species that are effectively annuals, and we wishedto see if these species had smaller genome sizes than averagefor the subtribe. Methods Fifty-four genome size estimates (50 of whichare new) for species in subtribe Oncidiinae (Orchidaceae) wereexamined for the first time in a phylogenetic context to evaluatehypotheses concerning genome sizes and life history traits. Results and Conclusions Within the limits of still relativelysparse sampling, the species that are effectively annuals doappear to have smaller genome sizes than average. However, thegenome sizes of their immediate sister group are also small,indicating that changes in genome size preceded the change inlife history traits. Genome sizes and chromosome numbers alsodo not correlate; some slowly growing species have lower chromosomenumbers but large genomes and vice versa. Based on a surveyof the literature on orchids, it is also clear that epiphyticspecies have smaller genome sizes than do terrestrial species,which could be an effect of different water relations or thefact that most terrestrial orchids are geophytic or have distinctgrowth and dormancy phases. 相似文献
69.
During 2 years spent conducting ecological fieldwork on Siberut, the largest and most northerly of the four Mentawai Islands
in Indonesia, incidental observations were made of the Mentawai macaque. The Mentawai macaque has been considered variously
as a full species similar in some respects to the long-tailed macaque and as a subspecies of the pig-tailed macaque. Evidence
is presented that a hitherto undescribed form of the Mentawai macaque occurs on Siberut, and aspects of its ecology and behavior
are described. 相似文献
70.