• Biomedical Science Letters
• /
• v.18 no.3
• /
• pp.324-327
• /
• 2012

Acanthamoeba is a free-living amoeba that causes human infections, and recently the incidence of amoebic keratitis has increased among contact lens wearers. In order to investigate Acanthamoeba contamination of contact lens storage cases, a short survey was performed on 57 contact lens wearers, and Acanthamoeba was found in one contact lens storage case. To diagnose Acanthamoeba, the 18s small subunit ribosomal DNA (18s rDNA) gene was amplified by polymerase chain reaction (PCR), and subsequently, the isolate was identified as A. lugdunensis. This species was originally isolated from a freshwater pool in France, and was reported recently to be a cause of amoebic keratitis. This observation indicates the need for a large survey to investigate the extent of Acanthamoeba contamination, and suggests that contact lens wearers be aware of the importance of hygiene and of the implications of Acanthamoeba infection.

• Korean Journal of Microbiology
• /
• v.49 no.3
• /
• pp.270-274
• /
• 2013

The bumblebee, Bombus terrestris, has played an important role as one of the alternative pollinators since the outbreak of honeybee collapse disorder. Recently, pathogens and parasites such as viruses, bacteria and mites, which affect the life span and fecundity of their host, have been discovered in B. terristris. In order to detect the microsporidian pathogen, Nosema spp. in the field populations of B. terristris, we collected adults and isolated their genomic DNA for diagnostic PCR. The PCR primers specific for Nosema spp. were newly designed and applied to gene amplification for cloning. Only small subunit ribosomal RNA (SSU rRNA) gene of N. ceranae was successfully amplified among examined genes and sequenced, which indicates that N. ceranae mainly infects the examined field population of B. terristris. To detect of SSU rRNA gene, two regions of SSU rRNA gene were selected by primary PCR analysis and further analyzed in quantitative real-time PCR (qRT-PCR). The qRT-PCR analysis demonstrated that SSU rRNA of N. ceranae was detected at concentration as low as $0.85ng/{\mu}l$ genomic DNA. This result suggests that the detection via qRT-PCR can be applied for the rapid and sensitive diagnosis of N. ceranae infection in the field population as well as risk assessment of B. terristris.

• Korean Journal Plant Pathology
• /
• v.14 no.5
• /
• pp.519-525
• /
• 1998

Intraspecific genetic diversity of Korean isolates of Phytophthora drechsleri was investigated based on PCR-RFLP of rDNA along with closely related species in the genus; P. cryptogea, P. melonis, P. erythroseptica, P. cinnamomi, P. cambivora and P. cactorum. Gene regions of nuclear small subunit and internal transcribed spacer (ITS) in rDNA were amplified with polymerase chain reaction and digested with 9 restriction enzymes. Phytophthora species was readily differentiated from each other based on the digestion patterns, however, P. cryptogea was not separable from some isolates of P. drechsleri. Twenty one isolates of P. drechsleri originated from 15 host plants were divided into three distinct groups designated as PdG1, PdG2 and PdG3, respectively. Four isolates in PdG1 were originated from green vegetables and tomato and nine isolates in PdG2 were mainly isolated from medicinal plants. The two groups showed 95.3% homology and four isolates of P. cyptogea came under the groups. However, Eight isolates in PdG3 collected from cucurbits were clearly differentiated from those of PdG1 and PdG2 by 66.5% homology, but completely matched with a Taiwan isolate of P. melonis. Results indicated that three distinct groups exist in Korean isolates of P. drechleri and each group has host preference. In addition, reclassification of the cucurbits isolates are reserved because of their distinct genetic characters from other intraspecific groups in P. drechsleri.

• ALGAE
• /
• v.22 no.1
• /
• pp.1-10
• /
• 2007

To gain insights into the phylogenetic relationships of genus Staurastrum and Staurodesmus, we analyzed nuclearencoded small subunit rDNA of 82 strains, and chloroplast atpB gene sequences of 44 strains belonging to three genera (Staurastrum, Staurodesmus, Cosmarium). Excluding the Staurastrum muticum and S. orbiculare, forty five strains of genus Staurastrum formed a well supported clade. It was shown that with no cell wall sculpture and processes, these two species have a strong phylogenetic relationship with genus Staurodesmus. Therefore, it is strongly recommended to transfer Staurastrum without processes and cell wall sculpture into Staurodesmus. S. obsoletus is a taxa that is transferred from Cosmarium. But, from this study, it has shown a phylogenetic relationship with Cosmarium. Therefore, this species is strongly recommended to transfer back to Cosmarium instead of Staurodesmus. As it was studied before, genus Staurastrum has shown monophyletic. Since the genus taurodesmus groups with Cosmarium, they were shown to be polyphyletic.

• Parasites, Hosts and Diseases
• /
• v.49 no.3
• /
• pp.281-284
• /
• 2011

Amebiasis is a protozoan disease caused by Entamoeba histolytica and a potential health threat in areas where sanitation and hygiene are inappropriate. Highly sensitive PCR methods for detection of E. histolytica in clinical and environmental samples are extremely useful to control amebiasis and to promote public health. The present study compared several primer sets for small subunit (SSU) rDNA and histone genes of E. histolytica cysts. A 246 bp of the SSU rDNA gene of pure cysts contained in phosphate-buffered saline (PBS) and in stool samples was successfully amplified by nested PCR, using the 1,147-246 bp primer set, of the primary PCR products which were pre-amplified using the 1,147 bp primer as the template. The detection limit of the nested PCR using the 1,147-246 primer set was 10 cysts in both groups (PBS and stool samples). The PCR to detect histone gene showed negative results. We propose that the nested PCR technique to detect SSU rDNA can be used as a highly sensitive genetic method to detect E. histolytica cysts in stool samples.

• The Plant Pathology Journal
• /
• v.22 no.1
• /
• pp.36-45
• /
• 2006

Twenty isolates of Didymella bryoniae were isolated from infected cucurbit plants in various growing areas of southern Korea in 2001 and 2002. Random Amplified Polymorphic DNA (RAPD) group [RG] I of D. bryoniae was more virulent than RG IV to watermelon. Virulence of the RG I isolate was strong to moderate to cucumber, whereas that of the RG IV varied from strong, moderate to weak. Two hundred seventy-three amplified fragments were produced with 40 primers, and were analyzed by a cluster analysis using UPGMA method with an arithmetic average program of NTSYSPC. At the distance level of 0.7, two major genomic DNA RAPD groups were differentiated among 20 isolates. The RG I included 7 isolates from watermelon and one isolate from melon, whereas the RG IV included 12 isolates from squash, cucumber, watermelon and melon. Amplification of internal transcribed spacer (ITS) region and small subunit rRNA region from the 20 isolates yielded respectively a single fragment. Restriction pattern with 12 restriction enzymes was identical for all isolates tested, suggesting that variation in the ITS and small subunit within the D. bryoniae were low. Amplification of the genomic DNAs of the tested isolates with the sequence characterized amplified regions (SCAR) primer RG IF-RG IR specific for RG I group resulted in a single band of 650bp fragment for 8 isolates out of the 20 isolates. Therefore, these 8 isolates could be assigned into RG I. The same experiments done with RG IIF-RG IIR resulted in no amplified PCR product for the 20 isolates tested. An about 1.4 kb-fragment amplified from the RG IV isolates was specifically hybridized with PCR fragments amplified from genomic DNAs of the RG IV isolates only, suggesting that this PCR product could be used for discriminating the RG IV isolates from the RG I isolates as well other fungal species.

• Journal of Life Science
• /
• v.16 no.1
• /
• pp.71-75
• /
• 2006

We analyzed the phylogenic relationships of 23 partial 18S rDNA sequences of 22 species (1 species has 2 strains) belonging to Sarcorptiforms include 4 new sequences, using several tools. Although geographic distributions are quite far from, sequence similarity of two strains of Dermatophygoides pteronyssinus isolated from Japan and New Zealand were very high. This result suggests that mite migration by animals including human occurred in the two continents. We investigated the Endeostigmata taxonomic relationship between the Prostigmata and Oribatida subgroups using small fragments (340-400 bp) of their 185 rDNA sequences. But Endeostigmata was not grouped with Oribatida or Prostigmata. In conclusion, it is first reported phylogenic relationship for classified mites included in Sarcoptiformes using 185 rDNA sequence analysis and its system is a very powerful tool for classification of mites.

• Animal Systematics, Evolution and Diversity
• /
• v.26 no.1
• /
• pp.21-27
• /
• 2010

Two marine euplotid ciliates, i.e. Euplotes cristatus Kahl, 1932 and E. minuta Yocom, 1930, were collected from the public waterfront of Incheon on the Yellow Sea and from the Songjeong Beach, Busan, in the Strait of Korea, respectively. These two species were verified as unrecorded species in Korea. These species were described based on live observation, protargol impregnation, and silver nitrate impregnation. In addition, the small subunit ribosomal DNA (SSU rDNA) sequences of the two species were compared with previously known sequences of the Euplotes species. Euplotes cristatus has an elongated oval form, size in vivo of $60-84{\times}38-68\;{\mu}m$, 35-50 adoral zone of membranelles (AZM), 10 frontoventral cirri (FVC), 5 transverse cirri (TC), 4-5 caudal cirri (CC), 8 dorsal kineties (DK), 10-16 dorsal cilia of middle DK, and silverline system of single-vannus type. Euplotes minuta has a small ovoid form ($44-53{\times}26-35\;{\mu}m$ in vivo), 31-41 AZM, 10 FVC, 5 TC, 4 CC, 9 DK, 10-12 dorsal cilia of middle DK, and silverline system of single-vannus type.

• Parasites, Hosts and Diseases
• /
• v.34 no.2
• /
• pp.127-134
• /
• 1996

Twelve isolates of Accnthamoebc app. assigned to either A. castellanii or A. poIMphoSa, and type strains of A. culbefsoni, A. henIWi, A. pqkestinefiE, and A. astronyxi,s were examined by restriction fragment length polymorphism (RFLP) of a conserved region of small subunit ribosomal RMh gene (ssu rDNA) amplified by polymerase chain reaction (PCR). The PCR products of the isolates measured approximately 910-930 bp, except for that of A. astronyxis which was extraordinarily long, approximately 1,170 bp. Average of estimated sequence divergence of the amplified DNA among the isolates assigned to A. castellanii was 9.8% whereas that among the isolates assigned to A. polvphusn 9.6%. The maximum intraspecific sequence divergence among the isolates assigned to A. costellanii was observed between the Chang and Ma strains (17.3%) while that among the isolates assigned to A. poIWphosa was observed between KA/S3 and KA/S7 strains (16.1%). The both maximum sequence divergences were much greater than the minimum interspecific sequence divergence between A. cnstellnnii and A. polwphasa (2.6%) which appeared between the Castellani (or CCAP 1501/12 g) and KA/S3 strains. The PCR-RFLP patterns of A. culbertsoni, A. healyi, A. palestinensis, and A. ostronvxis were quite diverse from one another and from those of isolates assigned to either A. castellanii or A. polyphoga. It is suggested that taxonomic validity of the isolates assigned to either A. castellnnii or A. polyphoga should be reevaluated.

• ALGAE
• /
• v.33 no.1
• /
• pp.1-19
• /
• 2018

Members of the family Parviluciferaceae (Alveolata, Perkinsozoa) are the well-known dinoflagellate parasitoids along with Amoebophrya ceratii species complex and parasitic chytrid Dinomyces arenysensis and contain six species across three genera (i.e., Parvilucifera infectans, P. sinerae, P. rostrata, and P. corolla, Dinovorax pyriformis, and Snorkelia prorocentri) so far. Among Parvilucifera species, the two species, P. infectans and P. sinerae, are very similar or almost identical each other morphologically and genetically, thereby make it difficult to distinguish between the two. The only main difference between the two species known so far is the number of sporangium wall (i.e., 2 layers in P. infectans vs. 3 layers in P. sinerae). During sampling in Masan bay, Korea during the spring season of 2015, the dinoflagellate Akashiwo sanguinea cells infected by the parasite Parvilucifera were observed and this host-parasite system was established in culture. Using this culture, its morphological and ultrastructural features with special emphasis on the variation in the number of sporangium wall over developmental times, were investigated. In addition, the sequences of rDNA regions and ${\beta}-tubulin$ genes were determined. The result clearly demonstrated that the trophocyte at 36 h was covered with 4 layers, and then outer layer of the sporocyte gradually degraded over time, resulting in wall structure consisting of two layers, with even processes being detached from 7-day-old sporangium with smooth surface, indicating that the difference in the number of layers seems not to be an appropriate ultrastructural character for distinguishing P. infectans and P. sinerae. While pairwise comparison of the large subunit rDNA sequences showed 100% identity among P. infectans / P. sinerae species complex, genetic differences were found in the small subunit (SSU) rDNA sequences but the differences were relatively small (11-13 nucleotides) compared with those (190-272 nucleotides) found among the rest of Parvilucifera species (P. rostrata and P. corolla). Those small differences in SSU rDNA sequences of P. infectans / P. sinerae species complex may reflect the variations within inter- strains of the same species from different geographical areas. Taken together, all morphological, ultrastructural, and molecular data from the present study suggest that they are the same species.