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91.
Debra L. Forthman Suzanne D. Elder Roger Bakeman Timothy W. Kurkowski Constance C. Noble Samuel W. Winslow 《Zoo biology》1992,11(3):187-195
Bears are extremely popular among the zoo-going public, yet while many zoo exhibits have undergone dramatic design changes in recent years, most bears continue to be housed in moated grottos constructed largely of gunite. In these traditional exhibits they frequently demonstrate stereotypic locomotor patterns and are often encouraged by the public to beg. Thus, the manner in which most captive bears are exhibited does not facilitate conservation education. It is possible, however, to provide bears with opportunities to demonstrate species-typical feeding and foraging behaviors, even in standard exhibits. Subjects were four individuals of three bear species. Feeding enrichment was provided to one bear per week during three mornings during the summers of 1989 and 1990. Overall, animals were more active, less passive and less often engaged in abnormal behaviors during sessions with enrichment. Effects showed individual variation and were more profound during the second year of the study, when a greater variety of enrichment items was presented. These results suggest that simple and inexpensive methods of enrichment may have a significant, positive influence on the behavior of captive bears. © 1992 Wiley-Liss, Inc. 相似文献
92.
Françoise Farace Anne-Marie Le Ridant Bernard Escudier Thierry Hercend Frédéric Triebel 《Biotherapy》1992,5(1):11-20
We have attempted to improve negative selection procedures for the large scale purification of human CD
in3
–
CD56+ NK cells. In a series of experiments, purifications of NK cells from 108 PBMC were performed by T cell depletion using either direct or indirect anti-CD3 labeling and the Magnetic Activated Cell Separation (MACS) procedure. Contaminating CD3+ cells were still present using either one of these two different T cell depletion protocols as shown by phenotyping IL-2 supplemented cell cultures on day 12. A second cycle of purification was therefore added. When MACS and Dynabeads were compared as complementary procedures to the first MACS cycle starting with 108 cells, the Dynabeads method was found to be superior to the MACS with regard to the elimination of residual T cells. Starting from 109 PBMC, we showed that this MACS+Dynabeads procedure gave similar satisfactory results when compared to the scaling-up of a previously established two steps procedure using Dynabeads. These two approaches (MACS+Dynabeads and 2 cycles of Dynabeads) have been also tested in a clinical setting to purify NK cells from cancer patients prior toin vitro expansion. The results indicate that the two methods are equivalent with respect to purity and recovery rate; a slight advantage in terms of feasibility was found in favor of 2 cycles of Dynabeads. 相似文献
93.
I Zbieranowski J C Le Riche B Palcic R Gascoyne J Connors 《Analytical cellular pathology》1992,4(4):303-313
Paraffin-embedded tissue from a series of 40 cases of diffuse, large cell lymphoma was analyzed by both flow and image cytometry to compare the ability of these techniques to detect DNA aneuploid populations. Image cytometry (ICM) was performed both on nuclear suspensions and tissue sections. Twenty cases (50%) were non-diploid by at least one method of analysis. Twenty-five percent of the cases were aneuploid by flow cytometry (FCM) alone. The majority of these cases were near-diploid tumors which could not be resolved by ICM. Peri-tetraploid peaks were identified by ICM of tissue sections alone in 15% of the cases. There was an apparent loss of these peri-tetraploid cells during the preparation of the nuclear suspensions. The remaining cases showed a good correlation between all three methods in the determination of DNA ploidy. Flow and image cytometry are complimentary techniques when applied to archival tissue, however aneuploid populations may be missed if ICM is not performed on tissue sections. 相似文献
94.
Summary The objectives of this study were to determine if biotin-labelled total genomic DNA of rye (Secale cereale L.) could be used to (i) preferentially label rye meiotic chromosomes in triticale and (ii) detect translocation stocks at interphase and/or early prophase by in situ hybridization. Welsh triticale, a wheat-rye segmental amphiploid, and Kavkaz wheat, a wheat-rye translocation were used. The results indicated that labelled chromosomes of rye and unlabelled chromosomes of wheat could be observed throughout all meiotic stages in the triticale. For Kavkaz wheat, the presence of the translocated 1RS chromosome arm of rye was detected at the interphase or very early prophase stage. Rapid assessment of feasibility of gene transfers and detection of alien DNA in somatic cells at the interphase stage by in situ hybridization allows for rapid decision-making and saves time and expense in plant breeding programs.Plant Research Centre Contribution No. 1276 相似文献
95.
The survival, development and mycorrhizal efficiency of a selected strain of Laccaria bicolor along with naturally occurring ectomycorrhizal fungi in a young plantation of Douglas fir was examined. Symbionts were identified and their respective colonization abilities were determined. Eight species of symbiotic fungi, which may have originated in adjacent coniferous forests, were observed on the root systems. Mycorrhizal diversity differed between inoculated (5 taxa) and control (8 taxa) seedlings. Ectomycorrhizal fungi which occurred naturally in the nursery on control seedlings (Thelephora terrestris and Suillus sp.) did not survive after outplanting. Both inoculated and naturally occurring Laccaria species, as well as Cenococcum geophilum, survived on the old roots and colonized the newly formed roots, limiting the colonization by other naturally occurring fungi. Other fungi, such as Paxillus involutus, Scleroderma citrinum and Hebeloma sp. preferentially colonized the old roots near the seedling's collar. Russulaceae were found mainly in the middle section of the root system. Mycorrhizal colonization by Laccaria species on inoculated seedlings (54%) was significantly greater than on controls (13%) which were consequently dominated by the native fungi. Significant differences (up to 239%) were found in the growth of inoculated seedlings, especially in root and shoot weight, which developed mainly during the second year after outplanting. Seedling growth varied with the species of mycorrhizae and with the degree of root colonization. Competitiveness and effectiveness of the introduced strain on improving growth performances of seedlings are discussed. 相似文献
96.
Abscisic acid (ABA) uptake by Amaranthus tricolor cell suspensions was found to include both a nonsaturable component and a saturable part with Km of 3.74 ± 0.43 micromolar and an apparent Vmax of 1.5 ± 0.12 nanomoles per gram per minute. These kinetic parameters as well as the uptake by intact cells at 0°C or by frozen and thawed cells, are consistent with operation of a saturable carrier. This carrier-mediated ABA uptake was partially energized by ΔpH: it increased as the external pH was lowered to pH 4.0; it decreased after the lowering of the ΔpH by the proton ionophore carbonylcyanide-m-chlorophenylhydrazone or after the altering of metabolically maintained pH gradient by metabolic inhibitors (KCN, oligomycin). The carrier is specific for ABA among the plant growth regulators tested, is unaffected by (RS)-trans-ABA and was inhibited by (S)-ABA, (R)-ABA, and also by the ABA analog LAB 173711. 相似文献
97.
The candidate gene for the X-linked Kallmann syndrome encodes a protein related to adhesion molecules 总被引:34,自引:0,他引:34
R Legouis J P Hardelin J Levilliers J M Claverie S Compain V Wunderle P Millasseau D Le Paslier D Cohen D Caterina 《Cell》1991,67(2):423-435
Kallmann syndrome associates hypogonadotropic hypogonadism and anosmia and is probably due to a defect in the embryonic migration of olfactory and GnRH-synthesizing neurons. The Kallmann gene had been localized to Xp22.3. In this study 67 kb of genomic DNA, corresponding to a deletion interval containing at least part of the Kallmann gene, were sequenced. Two candidate exons, identified by multiparameter computer programs, were found in a cDNA encoding a protein of 679 amino acids. This candidate gene (ADMLX) is interrupted in its 3' coding region in the Kallmann patient, in which the proximal end of the KAL deletion interval was previously defined. A 5' end deletion was detected in another Kallmann patient. The predicted protein sequence shows homologies with the fibronectin type III repeat. ADMLX thus encodes a putative adhesion molecule, consistent with the defect of embryonic neuronal migration. 相似文献
98.
99.
Mapping of the structural gene for S-adenosyl homocysteine hydrolase to mouse Chromosome 2, and related sequences to Chromosomes 8 and X 总被引:1,自引:0,他引:1
Alison Pilz Paul Le Tissier Heather Moseley Jo Peters Cathy Abbott 《Mammalian genome》1992,3(11):633-636
Comparative mapping studies in human and mouse have shown that, to date, human Chromosome (Chr) 20 is completely syntenic with distal mouse Chr 2. The structural locus for S-adenosyl-l-homocysteine hydrolase (EC 3.3.1.1) in human, AHCY, maps to 20 qterq13.1, and we report here that the homologous locus in the mouse, Ahcy, maps to distal mouse Chr 2 with gene order Pcna-Ahcy-Ada. Analysis of 123 progeny of an interspecific backcross between a laboratory stock, AN, and Mus spretus using a rat cDNA probe revealed the presence of at least two other Ahcy-related sequences segregating independently in the mouse genome. One, Ahcy-rs1, was mapped to Chr 8 in the BXH recombinant inbred strains, and the other, Ahcy-rs2, shows a pattern of inheritance consistent with X-linkage. 相似文献
100.
J. Le Dérout David S. Thaler † Nancy Guillén‡ Luisa Hirschbein 《Molecular microbiology》1992,6(11):1495-1505
Bacillus subtilis can exist in a diploid state in which two genetically distinct chromosomes co-exist in the same cell and yet only one of them is expressed, thereby determining the phenotype. Such cells are called non-complementing diploids (Ncds). In this study, two types of experiments are reported which indicate that a previously known pleiotropic gene, spo0A, plays a role in the maintaining the diploid state, as follows. (i) When protoplasts of two Spo0A mutant strains were fused, the resulting products continued to segregate cells of both parental phenotypes for many more divisions than had been reported previously. (ii) When a stable Ncd (an Ncd in which the unexpressed markers are not spontaneously activated at a detectable level) harbouring a chloramphenicol acetyltransferase gene on the silent chromosome was transformed with spo0A null alleles the transformants often expressed chloramphenicol acetyltransferase activity. Together these results indicate that the spo0A gene is involved in maintenance of the diploid state in both unstable and stable Ncds. 相似文献