Institute of Parasitology, Slovak Academy of Sciences, Hlinkova 3, 040 01, Košice, Slovakia.
Institute of Entomology, Biology Centre CAS, Branišovská 31, 370 05, České Budějovice, Czech Republic.
Parasitol Res. 2019 Oct;118(10):2789-2800. doi: 10.1007/s00436-019-06450-3. Epub 2019 Sep 4.
An original cytogenetic study combining classical karyotype analysis and modern fluorescence in situ hybridization using telomeric (TTAGGG) and ribosomal sequences (18S rDNA) was performed in Khawia abbottinae (Cestoda, Caryophyllidea), a parasite of Chinese false gudgeon (Abbottina rivularis) from China. Analyses based on conventional Giemsa staining, DAPI, YOYO-1 dye, and silver (Ag) staining were also carried out. The karyotype is composed of eight pairs of metacentric and telocentric chromosomes (2n = 16, n=5m + 3t). Constitutive heterochromatin was mainly positioned at pericentromeric regions, and telomeric sequences (TTAGGG) were restricted to the end of all chromosomes. In mitotic preparations stained with Giemsa, both homologues of chromosome pair 4 showed a distinct secondary constriction. FISH with rDNA probe confirmed that this secondary constriction contains a nucleolar organizer region (NOR). The process of spermatocyte meiosis and the dynamics of nucleolus degradation in dividing cell were scrutinized. The present study and its results enhance the limited knowledge on basic karyotype characteristics and 18S rDNA clusters location in caryophyllidean tapeworms.
对一种产自中国的中华假鱲（Abbottina rivularis）的绦虫——克氏副叶目绦虫（Cestoda， Caryophyllidea）进行了一项原始细胞遗传学研究，该研究结合了经典的核型分析和使用端粒（TTAGGG）和核糖体序列（18S rDNA）的现代荧光原位杂交技术。还进行了基于常规吉姆萨染色、DAPI、YOYO-1 染料和银（Ag）染色的分析。该染色体组由 8 对中央着丝粒和近端着丝粒染色体组成（2n = 16，n=5m + 3t）。组成性异染色质主要位于着丝粒区域，端粒序列（TTAGGG）仅限于所有染色体的末端。在吉姆萨染色的有丝分裂制剂中，染色体对 4 的两个同源物都显示出明显的次缢痕。用 rDNA 探针进行的 FISH 证实，这个次缢痕包含一个核仁组织者区域（NOR）。仔细研究了精母细胞减数分裂过程和分裂细胞中核仁降解的动态。本研究及其结果增强了对叶目绦虫基本核型特征和 18S rDNA 簇位置的有限认识。
