山茶属5种植物的核型研究

 本文报道了山茶属5种植物的核型:1.矩叶茶Camellia grijsii Hance核型公式为2n=2x=30=20m+7sm+3st;2.文山毛蕊茶C.wenshanensis Hu核型公式为2n=2x=30=20m+8sm+2st;3.紫果茶C.purpura Chang et Chen核型公式为2n=2x=30=22m+4sm+4st;4.显脉金花茶C.euphelebia Merr.ex Sealy核型公式为2n=2x=30=21m(4sat)+9sm(2sat);5.五柱滇山茶C.yunnanensis(Pitard ex Diels)Cohen Stuart核型公式为2n=2x=30=26m(2sat)+4sm.这5种植物分属不同的亚属及组.结果表明它们均是二倍体2n=30,但核型结构明显不同.核型类型前2种属2A型,后3种属2B型.     

八倍体小滨麦与硬粒小麦杂交F1的细胞遗传学研究

八倍体小滨麦(OctoploidTritileymus)与硬粒小麦(Triticumdurum)的杂交研究结果表明以八倍体小滨麦作母本,硬粒小麦作父本时,杂交结实率较高,平均为28.47%,而其反交结实率较低,平均仅为5.84%。杂种F1自交结实率极低,平均为1.11%;F1形态兼具硬粒小麦、普通小麦(Triticumaestivum)和滨麦(L.mollis)特性;杂种F1PMCMI染色体构型主要是14 14 ,平均为13.51 13.82 0.14 0.10 0.02 ,普通小麦D染色体组与滨麦J、N染色体组配对频率分别为3.02%和3.57%,说明D组与J、N组间基本无同源关系。同时杂种F1PMC后期有落后染色体排列在赤道板上,末期和末期出现大量二分孢子、四分孢子带微核现象。     

Hybridization among Epimedium (Berberidaceae) species native to China

The hybridization of fourteen plant populations belonging to seven Epimedium species native to China was studied by self-cross, infra-population cross, inter-population cross within species, and interspecific cross. Self-pollination studies on nine populations indicated high incompatibility; capsule-set rates were higher than zero in only three (4.61–6.76%). Interspecific cross-pollinations demonstrated high crossabilities in most cross combination (15.38–92.44% capsule-set rate), and the F₁ seeds possessed high germination rates (>20%). The F₁ hybrids of three interspecific cross combinations were raised to maturity. The morphology, karyomorphology of somatic cells, and pollen mother cell (PMC) meiosis of these F₁ plants revealed that they were all highly fertile (>76.10% in pollen viability), that there were few structural differences in chromosomes among species, and that most PMCs had 6 bivalents at MI. Abnormal chromosomal behaviors occurred in a minority, including chromosome bridges, unequal segregation of chromosome number, lagging chromosomes, and micronuclei. A series of experimental crosses provided strong evidence for an outbreeding system and a weak internal barrier to hybridizations in the taxa studied.     

Effects of maxadilan on proliferation of human induced pluripotent stem cells

AIM: To investigate the promoting effect of maxadilan, which specifically activate the type I receptor for pituitary adenylate cyclase-activating polypeptide (PACAP), on the proliferation of human induced pluripotent stem cells (IPSCs). METHODS: PACAP type I (PAC1) receptor in IPSCs was detected by RT-PCR and Western blotting. maxadilan at various concentrations was added to the medium of IPSCs as experimental groups. The medium in control group was without maxadilan treatment. The effect of maxadilan on theproliferation of IPSCs was measured with Cell Counting Kit-8 (CCK-8). The changes of cell cycle caused by maxadilan in IPSCs were analyzed by flow cytometry. The analysis of karyotype was carried out in IPSCs treated with maxadilan. Proteins and gene expression levels of both Nanog and OCT4 in IPSCs treated with maxadilan were detected by real-time quantitative polymerase chain reaction (real-time-qPCR) and immunofluorescence. The gene expression levels of Nestin and PAX6 in both IPSCs treated with maxadilan and cells of embryonic body, which was birthed from IPSCs with maxadilan treatment, were detected by real-time qPCR. The ability of IPSCs treated with maxadilan differentiating into 3 embryonic layers was evaluated by analyzing the component of embryo using RT-PCR. RESULTS: The PAC1 receptor in IPSCs was identified by RT-PCR and Western blotting. Viability of the IPSCs with 100 nmol/L maxadilan treatment was increased by 16% compared with control group. The differences with statistical significance were found in the cell viability between 100 nmol/L maxadilan treatment group and control group (P<0.05). The average values of proliferation index (PI) in IPSCs with 100 nmol/L maxadilan treatment for 3 h, 6 h and 9 h were 47.23%, 59.70% and 55.67%,respectively, while that in control group was 37.00%. The differences with statistical significance were found in PI between 100 nmol/L maxadilan treatment for 3 h group, 6 h group, 9 h group and control group (P<0.05). Normal karyotype and unchanged pluripotent state in IPSCs treated with maxadilan were observed. Compared with control group, the gene expression levels of Nestin and PAX6 were not significantly different in both IPSCs and the cells of embryonic body birthed from IPSCs with maxadilan treatment. The ability of differentiation into 3 embryonic layers in IPSCs treated with 100 nmol/L maxadilan was found. CONCLUSION: PAC1 receptor presents in IPSCs. Maxadilan promotes the proliferation of IPSCs but does not affect their pluripotent state and karyotype.     

Genetics of neotropical fish: from chromosomes to populations

The Neotropical freshwater fish fauna is very rich—according to the most recent catalogue 71 families and 4,475 species have been described. However, only a small amount of general information is available on the composition of Neotropical marine fishes. In Brazil, 1,298 marine species have been recorded. General analysis of available cytogenetic and population genetic data clearly indicates research has been mainly concentrated on freshwater fishes. Thus, today, cytogenetic information is available for 475 species of Characiformes, 318 species of Siluriformes, 48 species of Gymnotiformes, 199 freshwater species that do not belong to the superorder Ostariophysi, and only 109 species of marine fishes. For the species studied, only about 6% have sex chromosomes and about 5% have supernumerary or B chromosomes. A review of the cytogenetic studies shows that these data have provided valuable information about the relationships between fish groups, the occurrence of cryptic species and species complexes, the mechanism of sex determination and sex chromosome evolution, the distribution of nucleolus organizer regions, the existence supernumerary chromosomes, and the relationship between polyploidy and evolution. In relation to populations in Neotropical marine waters, the studies have shown the presence of cryptic species, which has important implications for fishery management. Different levels of genetic structuring can be found among Neotropical freshwater migratory fish species. This raises important implications for fish population genetic diversity and consequently its sustainable utilization in inland fisheries and aquaculture, specifically for conservation of ichthyo-diversity and survival.     

6个茶树品种染色体C-带的研究

采用 BSG 法,研究了6个茶树品种花蕾的染色体 C-带。结果表明,各品种多数染色体皆具有着丝点带,只有少数染色体同时具有端带或中间带。各品种染色体 C-带有不同的特征,主要表现在带纹的有无,位置和宽狭上。每个品种的同源染色体间的带纹亦存在一定的差异。本文还对不同作者对茶树染色体 C-带研究结果上的差异和品种间 C-带带纹的差异原因、研究 C-带的意义,以及研究的方法和应注意的问题进行了讨论。     

东北梅花鹿染色体C带和高分辨G带研究

采用外周血细胞培养、C分带技术对东北梅花鹿染色体进行研究,结果表明,不同地域东北梅花鹿染色体的结构异染色质可能存在一定程度上的多态性.采用氨甲喋呤阻断法使细胞分裂同步化,结合胰酶G显带技术对东北梅花鹿染色体进行研究,得到了高分辨G带核型,单倍体染色体显带数目增加至456条.     

Characteristics of chromosome of teratocarcinoma and its influence elements

AIM:To investigate the characteristics of chromosome of teratocarcinoma and its influence elements.METHODS:We used the methods of G-banded karyotype analysis,DNA basic sequence analysis and Western blot and the others,and studied the chromosome karyotype and the status of p53 gene of teratocarcinoma PA-1 cell line which had been cultured for 407-445 passages for 20 years. RESULTS: More than 80% PA-1 cells still maintained the near-diploid karyotype,after passage 30 the cells appeared with M1 and M2 chromosomal markers because of a balanced translocation between chromosomes 15 and 20. DNA directional sequence analysis of RP-PCR products revealed that there were both wild and mutated band (p53 codon 239 mutation), Western blot did not detect mutational p53 gene protein,while p21 protein expression lower than that in normal human fibroblasts. CONCLUSION:Missense mutation of one of the p53 allele gene of PA-1 cells in human teratocarcinoma was detected after cultured for more than twenty years, which was not sufficient to induce the instability of the chromosome of cell line.     

西镇牛的染色体研究

对２１头西镇牛的染色体核型、Ｇ带、Ｃ带及Ａｇ－ＮＯＲｓ进行了研究。结果表明，西镇牛公牛的核型为６０，ｘｙ，，母牛为６０，ｘｘ。Ｙ染色体近端着丝点染色体。     

Karyotype Variation within Some Natural Populations of Sulla (Hedysarum coronarium L., Fabaceae) in Algeria

As a part of the characterization and the valorization of plant genetic resources of fodder and pastoral interest in Algeria, a cytogenetic study was undertaken for nine natural populations of Hedysarum coronarium L. originating from North-East Algeria. The chromosomic characterization was realized throughout the mitosis, the C-banding and the meiosis analysis. Ecological factors (altitude and rainfall) of the originating environment of the different populations were considered in this study. Six Algerian populations present the stable chromosome number, usually observed in this species (2n = 16), whereas three others present two numbers. The first number (2n = 2x = 16), previously cited by other authors throughout the world, and the second one (2n = 2x = 18) is newly observed within Hedysarum coronarium L. Both mitotis ans meiosis confirmed these numbers. The chromosomes are median and the karyotype is primitive in terms of form and size. The C-banding method showed off three types of bands (telomeric, intercalary, centromeric). The originating environment seems to have an effect on the existing variability in Hedysarum coronarium L.