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S. E. Ashmore A. S. Shapcott 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1989,78(2):249-259
Summary Investigations have been carried out on karyotype change in both callus and suspension cell cultures of Haplopappus gracilis (2n=4). It has been found that polyploidization arises directly in culture to give up to six times the normal diploid chromosome number in some cultures. In polyploid cultures, both chromosome loss and chromosome rearrangements occur to give rise to aneuploid karyotypes displaying chromosomes which differ in morphology from the diploid set. Whole or partial chromosome loss has been observed in the form of lagging chromosomes and chromosome bridges at anaphase, and micronuclei, ring chromosomes and chromosome fragments at other stages in mitosis. C-banded preparations have confirmed the occurrence of chromosomal rearrangements. Comparative investigations suggest that (i) more polyploidy occurs in callus cultures than in suspension cell cultures, and (ii) the presence of cytokinin (kinetin) in the culture medium may reduce the extent of karyotype change. 相似文献
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Cloning and sequencing of the peroxisomal amine oxidase gene from Hansenula polymorpha 总被引:7,自引:0,他引:7
P G Bruinenberg M Evers H R Waterham J Kuipers A C Arnberg G AB 《Biochimica et biophysica acta》1989,1008(2):157-167
We have cloned the AMO gene, encoding the microbody matrix enzyme amine oxidase (EC 1.4.3.6) from the yeast Hansenula polymorpha. The gene was isolated by differential screening of a cDNA library, immunoselection, and subsequent screening of a H. polymorpha genomic library. The nucleotide sequence of a 3.6 kilobase stretch of DNA containing the amine oxidase (AMO) gene was determined. The AMO gene contains an open reading frame of 692 amino acids, with a relative molecular mass of 77,435. The 5' and 3' ends of the gene were mapped and show that the transcribed region measures 2134 nucleotides. The derived amino-acid sequence was confirmed by sequencing an internal proteolytic fragment of the purified protein. Amine oxidase contains the tripeptide sequence Ser-Arg-Leu, located 9 residues from the carboxy terminus, which may represent the topogenic signal for protein import into microbodies. 相似文献
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This study assessed the potential of two types of primate exhibit both for enhancing zoo visitors' interest, knowledge, and enjoyment and for promoting conservation education. Visitors' reactions to a free-ranging group of cotton-top tamarins were compared with their responses to caged tamarins in three ways: 1) timing how long visitors spent at each exhibit, 2) recording the comments made by visitors about the exhibits, and 3) asking visitors to respond to questionnaires about the two exhibits. The results showed that the free-ranging group of tamarins provoked wider comment from members of the public than caged groups and that visitors were willing to spend much more time looking for and watching monkeys in trees than monkeys in cages. Visitors felt that improvements in the animals' welfare were obtained from allowing them to live free in the trees, thought that they could learn more from such groups than from caged animals, and enjoyed seeing the free-ranging tamarins more than the monkeys in cages. These results suggest that developing more naturalistic zoo exhibits can have considerable benefits not only for the animals involved, but also for public education in conservation issues. © 1994 Wiley-Liss, Inc. 相似文献
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A. R. Gould S. E. Ashmore 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1982,64(1):7-12
Summary The polycation mediated attachment of purified tritiated DNA to plant protoplasts has been measured by quantitative microautoradiography. The automated grain counting technique used, also provides information on the cell cycle stage of individual protoplasts, which circumvents the need to synchronize the plant cell population before preparation of protoplasts. With protoplasts from asynchronously dividing suspension cultures of Nicotiana syhestris (NS-1), S-phase protoplasts appear to be inefficient binders of 3H-DNA, as compared with G1 or G2 protoplasts. Protoplasts derived from a tumour line of Crepis capillaris (CAPT) exhibit 3H-DNA binding at all cell cycle phases, but Sphase protoplasts appear to be preferential binders. These differences are discussed with reference to cell cycle kinetics, membrane charge variation and the possibility of increasing the efficiency of genetic transformation of higher plant cells in culture. 相似文献
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Summary Analysis of the cell cycle by three methods has revealed unusual kinetics of proliferation in tumour derived suspensions ofCrepis capillaris. The different methods of analysis yield different estimates of cycle phase durations, and such discrepancies have been explained in terms of low growth fractions with rapid total cycle traverse. Specifically, confidence in the estimation of G2 duration by the fraction of labelled mitosis analysis, and comparison with shorter G2 estimates obtained by the two other methods, suggests that cells drop out in G1. However, cells which do not drop out of the proliferative compartment traverse G1 extremely rapidly. Extremely short cell cycle durations in which the G1 phase is virtually non-existent are uncharacteristic of plant cell suspension cultures, in which the G1 phase has previously been shown to be extended as compared with meristematic root tip cells. A model has been proposed in which a central core of rapidly dividing cells continuously loses cells into a subpopulation of resting or G0 cells with the G1 DNA content. Similarities between plant and animal tumours with respect to cell growth and division are discussed. 相似文献
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A vitrification-based cryopreservation protocol was applied to in vitro sourced shoot-tips of four genotypes of Carica papaya; two female (70 and Z6) and two male (B2 and B4). Regeneration of ~58?% (70) and ~59?% (Z6) was recorded for the female genotypes confirming previously published results. Regeneration was at ~77 and ~53?% for the two male genotypes B2 and B4 respectively. Cryo-tube storage and regeneration was tested after 2?C18?months storage in one male (B2) and one female (70) genotype. Regeneration post cryo-storage was similar to 1?h exposure to liquid nitrogen. Individual shoot-tips from the two female and two male genotypes were grown into complete in vitro plants, potted and acclimatised without micropropagation to provide material for randomly amplified DNA fingerprinting (RAF) and amplified DNA methylation polymorphism (AMP) analysis of multiple individuals from in vitro control, plant vitrification solution 2 (PVS2) cryoprotectant control and short (1?h) and long-term cryopreservation treatment plants. No variations were detected for genotype Z6 control and treatment individuals and no RAF variations were detected in any individuals of genotype B2. Small numbers of RAF and AMP variations were detected in some individuals from genotypes B2 (AMP variation only), B4 and 70, but these were also found in controls. Genotype 70 showed the greatest level of variation; genomic DNA variation (RAF) was detected in control and cryopreservation treatment individuals, and the PVS2 control group was the only treatment group without variations for the respective AMP analysis. The variations observed could not be correlated with any phenotypic characteristics 2?months after acclimatisation. 相似文献