Chromosome structure and behaviour in Bursaphelenchus xylophilus (Nematoda: Parasitaphelenchidae) germ cells and early embryo
Chromosome structure and behaviour in Bursaphelenchus xylophilus (Nematoda: Parasitaphelenchidae) germ cells and early embryo
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DOI：
10.1163/156854106778493475
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发表时间：
2006-01-01
期刊：
影响因子：
1.2
通讯作者：
Miwa, Johji
中科院分区：
文献类型：
--
作者：
Hasegawa, Koichi;Mota, Manuel M.;Miwa, Johji
采用DAPI染色和激光共聚焦扫描显微镜连续切片图像三维重建技术，研究了松材线虫（Bursaphelenchus xylophilus）从受精到二细胞期生殖细胞减数分裂和胚胎有丝分裂的染色体结构和行为。通过这种方法，每个染色体的形状和行为在早期胚胎发生中清晰可见，从受精到配偶和雌性原核的形成和融合到第一次有丝分裂。雄性原核比雌性大，尽管卵母细胞比精子大，营养丰富。从分裂后期分离染色体的形态来看，有丝分裂染色体不是单着丝粒染色体，而是多着丝粒染色体或全着丝粒染色体。在雄性和雌性生殖细胞、单细胞期胚胎的原核和早期胚胎核中，每条染色体都可以清楚地区分。单倍体染色体数目为6条（2n = 12），染色体形态相似。通过荧光原位杂交观察含有核糖体RNA编码位点的染色体对。与秀丽隐杆线虫的性别决定系统（雌雄同体的XX和雄性的XO）不同，B. xylophilus可以由XX雌性和XY雄性组成。
Chromosome structure and behaviour in both meiosis of the germ cells and mitosis of the embryo from fertilisation to the two-cell stage in Bursaphelenchus xylophilus were examined by DAPI staining and three-dimensional reconstruction of serial-section images from confocal laser-scanning microscopy. By this method, each chromosome's shape and behaviour were clearly visible in early embryogenesis from fertilisation through the formation and fusion of the mate and female pronuclei to the first mitotic division. The male pronucleus was bigger than that of the female, although the oocyte is larger and richer in nutrients than the sperm. From the shape of the separating chromosomes at anaphase, the mitotic chromosomes appeared to be polycentric or holocentric rather than monocentric. Each chromosome was clearly distinguishable in the male and female germ cells, pronuclei of the one-cell stage embryo, and the early embryonic nuclei. The haploid number of chromosornes (N) was six (2n = 12), and all chromosomes appeared similar. The chromosome pair containing the ribosomal RNA-coding site was visualised by fluorescence in situ hybridisation. Unlike the sex determination system in Caenorhabditis elegans (XX in hermaphrodite and XO in male), the system for B. xylophilus may consist of an XX female and an XY male.