Parasitic diseases remain an unarguable public health problem worldwide. Liver fluke Clonorchis sinensis is a high risk pathogenic parasitic helminth which is endemic predominantly in Asian countries, including Korea, China, Taiwan, Vietnam, and the far eastern parts of Russia, and is still actively transmitted. According to the earlier 8th National Survey on the Prevalence of Intestinal Parasitic Infections in 2012, C. sinensis was revealed as the parasite with highest prevalence of 1.86% in general population among all parasite species surveyed in Korea. This fluke is now classified under one of the definite Group 1 human biological agents (carcinogens) by International Agency of Research on Cancer (IARC) along with two other parasites, Opisthorchis viverrini and Schistosoma haematobium. C. sinensis infestation is mainly linked to liver and biliary disorders, especially cholangiocarcinoma (CCA). For the purposes of this mini-review, we will only focus on C. sinensis and review pathogenesis and carcinogenesis of clonorchiasis, disease condition by C. sinensis infestation, and association between C. sinensis infestation and CCA. In this presentation, we briefly consider the current scientific status for progression of CCA by heavy C. sinensis infestation from the food-borne trematode and development of CCA.

From biological and genetic standpoints, centromeres play an important role in the delivery of the chromosome complement to the daughter cells at cell division. The positions of the centromeres of potato were determined by half-tetrad analysis in a 4x-2x population where the male parent produced 2n pollen by first-division restitution (FDR). The genetic linkage groups and locations of 95 male parent-derived amplified fragment length polymorphism markers could be determined by comparing their position on a 2x-2x highly saturated linkage map of potato. Ten centromere positions were identified by 100% heterozygosity transmitted from the 2n heterozygous gametes of the paternal parent into the tetraploid offspring. The position of these centromeric marker loci was in accordance with those predicted by the saturated 2x-2x map using the level of marker clustering as a criterion. Two remaining centromere positions could be determined by extrapolation. The frequent observation of transmission of 100% heterozygosity proves that the meiotic restitution mechanism is exclusively based on FDR. Additional investigations on the position of recombination events of three chromosomes with sufficient numbers of markers showed that only one crossover occurred per chromosome arm, proving strong interference of recombination between centromere and telomere.

SummaryThe devastating late blight pathogen Phytophthora infestans infects foliage as well as tubers of potato. To date, resistance breeding has often focused on foliage blight resistance, but tuber blight resistance is becoming more and more important in cultivated potatoes. In this study, a reliable tuber assay for resistance assessment was developed and foliage and tuber blight resistance (R) was compared in four mapping populations. In the RH4X-103 population, tuber blight resistance inherited independently from foliage blight resistance. Three specific R genes against P. infestans were segregating. The Rpi-abpt and R3a genes function as foliage-specific R genes, whereas the R1 gene acts on both foliage and tuber. In the segregating populations SHRH and RH94-076, tuber and foliage blight resistance correlated significantly, which suggests that resistance in foliage and tuber is conferred by the same gene (could be R3b) and quantitative trait loci (QTL), respectively. In the CE population neither tuber nor foliage resistance was observed.

The detailed karyotypes of diploid (2n = 2x = 24) and triploid (2n = 3x = 36) of L. tigrinum were constructed based on fluorescence in situ hybridization (FISH) using 5S rDNA and 45S rDNA probes. The lengths of mitotic metaphase chromosomes ranged from 15.92 to 30.18 um, with a total length/genome of 250.46 um in diploid, and 15.24 to 28.16 um, with a total length/genome of 233.42 um in triploid. The chromosome composed of two pairs of metacentrics (Chromosomes 1 and 2), four pairs of subtelocentrics (Chromosomes 3, 4, 5, and 6) and six pairs of telocentrics (Chromosomes 7, 8, 9, 10, 11, and 12) in diploid L. tigrinum, two pairs of metacentrics (Chromosomes 1 and 2), six pairs of subtelocentrics (Chromosomes 3, 4, 5, 6, 7, and 11) and four pairs of telocentrics (Chromosomes 8, 9, 10, and 12) in triploid L. tigrinum. Ten (Chromosomes 1, 2, 6, 7, and 11) or twelve (Chromosomes 1, 2, 4, 6, 7, and 11) loci of 45S rDNA were detected in the diploid chromosomes whereas fifteen loci were detected in triploid chromosomes (Chromosomes 1, 2, 6, 7, and 11). Two loci of 5S rDNAs were located close to each other at the both diploid and triploid chromosome 3. New cytotypes of secondary constriction were observed in diploid (1-1-1-0) and triploid (3-2-1-1).