巴西橡胶树MADS-box基因家族6个成员的染色体物理定位

MADS-box基因家族广泛分布于真核生物中,巴西橡胶树的MADS-box基因家族主要参与花形态建成,对生殖生长起到重要的调节作用。目前,MADS-box基因家族的26个相关基因已被克隆分析,但它们在染色体上的具体位置还未确定。本研究以巴西橡胶树‘热研7-33-97’品种为材料,将MADS-box基因家族的6个成员（HbAGL8、HbAG15、HbAGL30、HbTT16、HbAP1和HbSVP1）定位在细胞核染色体上,通过双探针荧光原位杂交技术（FISH）对巴西橡胶树MADS-box基因家族的这6个成员在细胞核染色体上进行物理定位分析。结果表明：MADS-box基因家族的6个基因分别位于不同的染色体上,其中HbAGL15、HbAG8、HbAG30和HbSVP1基因定位在第4、5、7和8号染色体长臂上,其信号位点到着丝粒的平均百分距离是11.85、39.71、48.94和6.70;HbTT16和HbAP1基因定位在第1和13号染色体短臂上,其信号位点到着丝粒的平均百分距离是22.19和18.01。本研究结果揭示了巴西橡胶树MADS-box基因家族的6个成员在细胞核染色体上的实际位置,展现家族基因之间的分布特点和连锁遗传关系,不仅丰富了橡胶树分子细胞遗传学信息,也为橡胶树的分子辅助育种和比较基因组学研究提供了分子细胞遗传学的科学理论依据。     

In-situ enrichment and analysis of atrazine-degrading microbial communities using atrazine-containing porous beads

We examined the community composition of microbes that colonized atrazine-containing beads buried in agricultural soils that differed in atrazine treatment history. Bacterial abundance was 5-40-fold greater in atrazine-fortified beads. In beads containing 20 mg atrazine kg⁻¹ buried in soil with a history of atrazine application (conditioned soil), the abundance of Actinobacteria increased approximately 80-fold whereas in control soil, Actinobacteria were enriched only 10-fold and the gamma-Proteobacteria and Planctomycetes increased by 60- and 25-fold, respectively. The gamma-Proteobacteria were enriched by 120- and 230-fold in beads containing 200 mg atrazine kg⁻¹ in conditioned and control soil, respectively. The results demonstrate that BioSep^® beads are a suitable matrix for recruiting a diverse subset of the bacterial community involved in atrazine degradation.     

小麦流式分选染色体的鉴定

构建染色体BAC文库对于简化拥有庞大基因组植物的测序、物理作图和基因克隆具有重要意义。分选染色体的鉴定是整个文库构建过程的关键环节之一。 本文在前人研究的基础上, 分别采用荧光原位杂交(FISH)、原位PCR(C-PRINS)和PCR方法, 对分选的6VS、3B和7BL染色体(臂)进行了鉴定。结果表明, 这3种方法都能对流式分选染色体进行有效鉴定, 其中PCR法速度最快、重复性好, 但结果不具可视性、也不能鉴定分选纯度; 而FISH法重复性好、结果具有可视性、能够鉴定分选纯度, 但操作程序复杂耗时, 受探针特异性的限制; C-PRINS法则综合了上述两种方法的优点, 是最具潜力的鉴定方法, 如果与液体原位杂交相结合, 有可能为解决染色体分选问题开辟新的途径, 但也存在重复性差、杂交信号不稳定的缺点。     

简单重复序列(AAG)_5在百萨偃麦草染色体上的分布

百萨偃麦草是小麦亲缘物种之一,对环境胁迫和生物胁迫具有很强的抗性,是小麦遗传改良的重要资源。为了对导入的外源染色体及片段进行有效鉴定,利用荧光原位杂交方法,研究了合成的简单重复序列(AAG)5在百萨偃麦草染色体上的分布情况。结果表明,(AAG)5在百萨偃麦草上有多个位点,利用(AAG)5作探针可以将百萨偃麦草的各条染色体区分开来。     

Acute myeloblastic leukemia with associated BCR-ABL translocation in a dog

An 8-year-old male neutered Labrador Retriever was referred to the University of Wisconsin Veterinary Medical Teaching Hospital with a presumptive diagnosis of leukemia. Hematologic abnormalities included normal neutrophil count with a left shift, monocytosis, eosinophilia, thrombocytopenia, and circulating immature mononuclear cells. Bone marrow was effaced by immature hematopoietic cells of various morphologic appearances. In addition, large multinucleated cells were observed frequently. Flow cytometric analysis of nucleated cells in blood revealed 34% CD34(+) cells, consistent with acute leukemia. By immunocytochemical analysis of cells in blood and bone marrow, some mononuclear cells expressed CD18, myeloperoxidase, and CD11b, indicating myeloid origin; some, but not all, large multinucleated cells expressed CD117 and CD42b, the latter supporting megakaryocytic lineage. The diagnosis was acute myeloblastic leukemia without maturation (AML-M1). To identify genetic aberrations associated with this malignancy, cells from formalin-fixed paraffin-embedded bone marrow were analyzed cytogenetically by multicolor fluorescence in situ hybridization (FISH). Co-localization of bacterial artificial chromosome (BAC) containing BCR and ABL was evident in 32% of cells. This confirmed the presence of the canine BCR-ABL translocation or Raleigh chromosome. In people, the analogous translocation or Philadelphia chromosome is characteristic of chronic myelogenous leukemia (CML) and is rarely reported in AML. BCR-ABL translocation also has been identified in dogs with CML; however, to our knowledge this is the first report of AML with a BCR-ABL translocation in a domestic animal.     

薄片牡蛎的核型及18S-28S核糖体rRNA基因的染色体定位

以薄片牡蛎（Dendostrea folium）成体鳃组织为材料制备有丝分裂中期染色体标本,对其染色体核型进行了分析,并运用荧光原位杂交技术（FISH）将18S-28S核糖体RNA基因定位于中期染色体上。FISH探针是通过PCR扩增介于18S-28S rRNA基因之间的ITS和5.8S rRNA基因序列,并在PCR扩增过程中掺入了Biotin-11-dUTP进行生物素标记。结果显示,薄片牡蛎的单倍染色体数目为n=10,全部为中部着丝粒染色体。与大多数已知巨蛎属牡蛎的染色体核型相似。ITS探针在薄片牡蛎中期分裂体相上产生两簇FISH信号,分别杂交于2号染色体短臂的近端粒区域。本研究首次报道了薄片牡蛎的中期染色体核型以及18S-28S核糖体RNA基因在染色体上的定位。     

Quantitative impact of CO2 enriched atmosphere on abundances of methanotrophic bacteria in a meadow soil

In the Giessen free-air CO₂ enrichment (GiFACE) experiment, 5 years of CO₂ enrichment led to decreased CH₄ uptake rates of the investigated meadow soil. In soils, CH₄ is mainly oxidised by methanotrophic bacteria. In the present study, abundances of methanotrophic bacteria and total bacteria in soil samples from the GiFACE experiment were quantified by applying pmoA- and 16S rRNA gene-targeted real-time PCR and fluorescence in situ hybridisation (FISH). Methanotrophic bacteria of the Methylosinus group (Alphaproteobacteria) and the Methylobacter/Methylosarcina group (Gammaproteobacteria) were detectable by real-time PCR as well as by FISH. Both quantitative analytical approaches revealed that abundances of either bacteria or methanotrophic bacteria in soil samples from sites under CO₂-enriched atmosphere were decreased. Compared to ambient site, only 46 and 30.5% of methanotrophic bacteria and 38 and 63.2% of total bacterial cell numbers could be detected under CO₂-enriched atmosphere by FISH and real-time PCR, respectively. These results suggest that significantly decreased abundances of methanotrophic bacteria could explain reduced CH₄ uptake rates.     

水仙荧光原位杂交体系的建立

摘要：建立以水仙染色体为靶、rDNA为探针的荧光原位杂交实验技术,为进一步利用荧光原位杂交技术分析水仙的亲缘和进化关系奠定了基础。水仙的染色体制片以去壁低渗-火焰干燥法较好,容易获得大量清晰、分散的有丝分裂中期相;切刻平移法地高辛标记探针、染色体和探针共变性90℃ 5 min能有效的进行水仙rDNA的染色体荧光原位杂交定位。     

DNA分子原位杂交在植物分子细胞遗传学研究中的应用

DNA分子原位杂交（in situ hybridiation）是植物分子细胞遗传学研究的重要工具。本文简要回顾了DNA分子原位杂交的起源和发展,详细综述了基因组原位杂交（genomic in situ hybridization, GISH）在植物细胞遗传学研究中的应用以及荧光原位杂交（Fluorescence in situ hybridization, FISH）在物理作图和染色体识别中的应用。文中还介绍了Fiber-FISH、BAC-FISH以及Immuno-FISH等新兴技术。最后对FISH技术进行了展望。