小麦×玉米杂交后代的蛋白质及酯酶同工酶分析

以８ 个普通小麦（Ｔｒｉｔｉｃｕｍ ａｅｓｔｉｖｕｍ Ｌ．）品种为母本,２ 个栽培玉米（Ｚｅａ ｍ ａｙｓ Ｌ．）品种为父本杂交所获得的Ｆ２ 代在形态上出现了明显变异。对其籽粒进行蛋白质电泳分析,得到了如下主要结果：杂交后代的蛋白质谱带较母本有了很大的变异,主要集中在高分子量麦谷蛋白（ＨＭＷ－Ｇｌｕ）区域。杂交后代的蛋白质谱带由５ 种类型构成：１．母本型,占全部测试籽粒的２２．６％ ;２．附加型,占１４．３％ ;３．互补型,占１５．５％ ;４．杂种型,占３０．９％ ;５．缺失型,占１６．７％ 。对“矮杆早”ד紫粘”的Ｆ２ 代籽粒进行酯酶同工酶电泳分析发现,变异主要发生在ＥＳＴ－１ 区。由此看来,小麦×玉米的杂合子中玉米染色体在被排除前后,可以诱发小麦染色体组发生遗传变异     

多胚水稻品系APⅣ的多卵遗传行为分析

通过多胚水稻品系APⅣ与单胚水稻品种IR36、明恢77和龙特浦B正反杂交, 研究APⅣ的多卵遗传行为,表明APⅣ的多卵性状可能不是由孢子体基因型决定的,而是由雄配子体基因型决定,属配子体遗传的范畴。 Abstract:The inheritance of poly-eggs was investigated by crossing and reciprocally crossing APIV with monoembryonic rice variety IR36,Minghui No.77 and Longtepu B,respectively.It was suggested that the production of poly-eggs is probably controlled by gametophytic genotypes,rather than sporophytic ones.     

The fate of ribosomal genes in three interspecific somatic hybrids of Medicago sativa: three different outcomes including the rapid amplification of new spacer-length variants

We have characterized the genetic consequences of somatic hybridization within the ribosomal DNA (rDNA) of three interspecific hybrids, each involving M. sativa as one of the parents. Restriction-fragment-length-polymorphisms (RFLPs) of rDNA spacers and fluorescent-in-situ-hybridization (FISH) of an 18S-gene probe to mitotic chromosomes were used to compare parental and hybrid species. The M. sativa-coerulea hybrid retained all six parental nucleolar-organizing regions (NORs) and all parental RFLPs representing a complete integration of rDNA. The M. sativa-arborea hybrid retained five of six parental NORs while losing half of the arborea-specific RFLPs, indicating that simple chromosome loss of one arborea NOR accounted for the RFLP losses. Dramatic alterations occurred within the M. sativa-falcata hybrid where five of six parental NORs were retained and new rDNA RFLPs were created and amplified differentially among somaclonal-variant plants. The molecular basis of the new RFLPs involved increased numbers of a 340-bp subrepeating element within the rDNA intergenic spacer (IGS), suggesting that recurrent cycles of unequal recombination occurred at high frequency within the rDNA in somatic lineages.This paper was supported by the National Research Council of Italy, Special Project RAISA, Sub-project No. 2, Paper No. 1077     

Intergeneric transfer of a partial genome and direct production of monosomic addition plants by microprotoplast fusion

Results are reported on the transfer of single, specific chromosomes carrying kanamycin resistance (Kan^R) and -glucuronidase (GUS) traits from a transformed donor line of potato (Solanum tuberosum) to a recipient line of the tomato species Lycopersicon peruvianum through microprotoplast fusion. Polyethylene glycol-induced mass fusion between donor potato microprotoplasts containing one or a few chromosomes and normal recipient diploid L. peruvianum protoplasts gave several Kan^R calli. A high frequency of plants regenerated from Kan^R calli expressed both Kan^R and GUS, and contained one or two copies of npt-II and a single copy of gus. Genomic in situ hybridization showed that several microprotoplast hybrid plants had one single potato donor chromosome carrying npt-II and gus genes and the complete chromosome complement of the recipient L. peruvianum (monosomic additions). Several monosomic-addition hybrid plants could be regenerated within the short time of 3 months and they were phenotypically normal, resembling the recipient line. These results suggest that the transfer of single chromosomes is tolerated better than is the transfer of the whole donor genome. The unique advantages of microprotoplast fusion are discussed: these include the direct production of monosomic addition lines for the transfer and introgression of economically important traits in sexually-incongruent species, the construction of chromosome-specific DNA libaries, high-resolution physical mapping and the identification of alien chromosome domains related to gene expression.     

Molecular-cytogenetic characterization of a higher plant centromere/kinetochore complex

The centromeric region of a telocentric field bean chromosome that resulted from centric fission of the metacentric satellite chromosome was microdissected. The DNA of this region was amplified and biotinylated by degenerate oligonucleotide-primed polymerase chain reaction (DOP-PCR)/linker-adapter PCR. After fluorescence in situ hybridization (FISH) the entire chromosome complement of Vicia faba was labelled by these probes except for the nucleolus organizing region (NOR) and the interstitial heterochromatin, the chromosomes of V. sativa and V. narbonensis were only slightly labelled by the same probes. Dense uniform labelling was also observed when a probe amplified from a clearly delimited microdissected centromeric region of a mutant of Tradescantia paludosa was hybridized to T. paludosa chromosomes. Even after six cycles of subtractive hybridization between DNA fragments amplified from centromeric and acentric regions no sequences specifically located at the field bean centromeres were found among the remaining DNA. A mouse antiserum was produced which detected nuclear proteins of 33 kDa and 68 kDa; these were predominantly located at V. faba kinetochores during mitotic metaphase. DNA amplified from the chromatin fraction adsorbed by this serum out of the sonicated total mitotic chromatin also did not cause specific labelling of primary constrictions. From these results we conclude: (1) either centromere-specific DNA sequences are not very conserved among higher plants and are — at least in species with large genomes — intermingled with complex dispersed repetitive sequences that prevent the purification of the former, or (2) (some of) the dispersed repeats themselves specify the primary constrictions by stereophysical parameters rather than by their base sequence.     

Interspecific hybridization of cultivated rice, Oryza sativa L. with the wild rice, O. minuta Presl.

Crosses were made between four varieties (Mahsuri, Setanjung, MR84 and MR103) of Oryza sativa L. (2n=24, AA) and one accession of O. minuta (2n= 8, BBCC). The seed set obtained ranged between 9.5% and 25.1% depending on the rice variety used. By rescuing 14-day-old embryos and culturing them on 25%-strength MS medium we obtained a total of 414 F₁ hybrids. The F₁s were vigorous, tillered profusely, were perennial and male-sterile. The hybrids were triploid (ABC) with 36 chromosomes and showed irregular meiosis. The average frequency and range of chromosome associations at metaphase I or early anaphase I pollen mother cells of F₁ plants were 29.31(16–36) Is +3.32(0–10) IIs+0.016(0–1) IIIs+0.002(0–1) IVs. Upon backcrossing the original triploid hybrids and colchicine-treated hybrids to their respective recurrent parents, and further embryo rescue, 17 backcross-1 (BC₁) plants were obtained. Of all the crosses using MR84, no BC₁ plant was obtained even after pollinating 13 894 spikelets of the triploid hybrid. The BC₁s were similar in appearence to the F₁s and were male-sterile, their chromosome number ranged from 44 to 48. By backcrossing these BC₁s and nurturing them through embryo rescue, we obtained 32 BC₂ plants. Of these, however, only 18 plants grew vigorously. One of these plants has 24 chromosomes and the other 17 have chromosome numbers ranging between 30 and 37. The 24-chromosome plant was morphologically similar to the O. sativa parent and was partially fertile with a pollen and spikelet fertility of 58.8% and 12.5% respectively. All of the F₁ and BC₁ plants were found to be resistant to five Malaysian isolates (XO66, XO99, XO100, XO257 and XO319) of Xanthomonas campestris pv oryzae. Amongst the BC₂s, the reaction varied from resistant to moderately susceptible. The 24-chromosome BC₂ plant was resistant to the four isolates and moderately resistant to isolate XO100 to which the O. sativa parent was susceptible.Part of PhD thesis submitted by first author to Universiti Kebangsaan Malaysia, Bangi     

Intergeneric somatic hybrid plantlets between Dianthus barbatus and Gypsophila paniculata obtained by electrofusion

Hypocotyl-derived protoplasts of Dianthus barbatus that had been pretreated with iodoacetamide were fused electrically with cell suspension culture-derived protoplasts of Gypsophila paniculata that could divide to form callus but could not regenerate shoots under the culture conditions used in this study. Electrofusion-derived calli which produced shoots were selected as putative somatic hybrids, and plantlets were subsequently regenerated from 2 of these selected calli. These plantlets, which in vitro produced flowers precociously, were identified as intergeneric somatic hybrids by nuclear ribosomal DNA analysis. Normal plants have not been established up to the present.     

大鼠脊髓内生长抑素mRNA原位杂交的研究

采用地高辛标记生长抑素反意ＲＮＡ探针经原位杂交和显色后,光学显微镜下观察生长抑素ｍＲＮＡ在大鼠脊髓内的定位。结果显示：脊髓内含有大量呈紫蓝色的生长抑素ｍＲＮＡ阳性神经细胞,岍性磷酸酶反应产生     

Specific detection of RNA molecules by fluorescent in situ hybridization in living cells

The antisense therapeutic strategy makes the assumption that sequence-specific hybridization of an oligonucleotide to its target can take place in living cells. The present work provides a new method for the detection of intracellular RNA molecules using in situ hybridization on living cells. The first step consisted in designing nonperturbant conditions for cell permeabilization using streptolysin O. In a second step, intracellular hybridization specificity was evaluated by incorporating various types of fluorescently labeled nucleic acid probes (plasmids, oligonucleotides). Due to its high expression level, the 28S ribosomal RNA was retained as a model. Results showed that: (1) no significant cell death was observed after permeabilization; (2) on living cells, 28S RNA specific probes provided bright nucleoli and low cytoplasmic signal; (3) control probes did not lead to significant fluorescent staining; and (4) comparison of signals obtained on living and fixed cells showed a colocalization of observed fluorescence. These results indicate the feasibility of specific hybridization of labeled nucleic acid probes under living conditions, after a simple and efficient permeabilization step. This new detection method is of interest for investigating the dynamics of distribution of various gene products in living cells, under normal or pathological conditions.Abbreviations PI propidium iodide - SLO streptolysin O