The morphological features of germling cells were examined to identify an unspecified resting cyst (described as Cochlodinium cf. polykrikoides-like resting cyst) in the Korean coastal area. LSU rRNA gene sequences were also obtained from a strain established from the germling cells. The resting cysts isolated from Korean coastal sediment were characterized as being brown in color, having a large dark-red body, and fibrous lobed ornaments. The germling cells were ellipsoidal with an irregular outline and had an open comma-shaped ASC (apical structure complex), a wide and deep cingulum, and a deep sulcus. These morphological features were consistent with those of previously described harmful dinoflagellate Pseudocochlodinium profundisulcus. The molecular phylogeny revealed that the germling cells and P. profundisulcus were conspecific. Based on these morphological and phylogenetic data, this study documents the occurrence of P. profundisulcus in a Korean coastal area for the first time.

The genus Desmodesmus (Chodat) S.S. An, T. Friedl & E. Hegewald is ubiquitous in freshwater ecosystems, such as rivers, ponds, and wetlands. The actual species diversity and distribution of the genus is unknown because of morphological plasticity affected by habitats. Currently, 38 Desmodesmus species have been reported in Korea most of which transferred from the genus Scenedesmus recently, however, no phylogenetic relationships have been studied yet. Despite the challenges in analyzing relationships among Desmodesmus species through the morphology, ecology, and original description, this study focused on examining species-level relationships using the FBCC culture strains isolated from Korea. A total of 299 sequences (66 of 18S rRNA, 47 of atpB, 67 of petA, 52 of rbcL, and 67 of tufA) were newly determined and used for phylogenetic analysis. Four plastid genes tend to have higher variation than 18S rRNA in the variable sites and P-distance. From the combined phylogeny, the Desmodesmus included six clades such as Clade-1: D. pseudoserratus and D. serratus, Clade-2: D. communis, D. dispar, D. maximus, D. pannonicus, unidentified Desmodesmus sp., Clade-3: D. bicaudatus and D. intermedius, Clade-4: D. microspina, D. multivariablis, D. pleiomorphus, D. subspicatus, Clade-5: D. abundans, D. kissii, and D. spinosus, and Clade-6: D. armatus, D. armatus var. longispina, D. opoliensis, unidentified Desmodesmus spp. The new sequence data from FBCC strains will be used to identify species and study the molecular ecology of scenedesmacean green algae in freshwater ecosystems. The phylogenetic information from this study will expand our understanding of Desmodesmus species diversity in Korea.

Miridae show remarkable diversity (>11,700 spp.), accounting for a quarter of all Heteroptera. However, their phylogeny and evolutional history is still remain unclear. In this work, we provide new suggestions for the phylogeny of Miridae using a larger dataset than previous studies. In addition, we suggest an alternative evolutionary history based on newly calibrated divergence dates for Miridae and its subordinate groups, and present probable factors of the family’s success in terms of species diversity. The entire dataset comprises 16 outgroups and 188 ingroup taxa including all seven known subfamilies and 37 out of 45 known tribes. Each species is aligned as 3,577 bp with six molecular loci (COI, 16S rRNA, 18S rRNA, 28S rRNA D3 region, H2A, and H3A).

The germination characteristics of the resting cysts of Pheopolykrikos hartmannii collected from the southern coastal sediments of Korea were studied at different temperature conditions, and the morphology and phylogeny of the germlings were examined. The resting cysts of Ph. hartmannii were round and characterized by a red accumulation body and many arrow-like spines and could germinate at temperature of 10 to 30°C. High germination rates (>90%) were observed at 15 and 20°C, indicating that the resting cysts could act as seed populations for the bloom initiation of Ph. hartmannii in Korean coastal waters in early summer or early fall. The morphology of the germlings was generally consistent with the previous description, and an apical groove characterized by a fully enclosed loop was observed. Phylogenetic analysis based on large SubUnit (LSU) rRNA gene sequences revealed that the germlings shared an identical sequence with the Korean and American isolates of Ph. hartmannii and was a sister clade of Polykrikos species.

A strain of Alexandrium species was established by isolating cells from Jangmok Bay, Korea. Its morphology and molecular phylogeny based on LSU rRNA gene sequences were examined. In addition, growth responses of this Alexandrium species to changes in temperature, salinity, and nutrient concentrations were investigated. This Alexandrium species from Jangmok Bay had a ventral pore on the 1′, which was morphologically consistent with previously described Alexandrium tamarense and A. catenella. Phylogenetic analyses revealed that this isolate was assigned to A. pacificum (Group IV) within A. tamarense species complex. In growth experiments, relatively high growth rates and cell densities of A. pacificum (Group IV) were observed at 15°C and 20°C. This species also grew under a wide range of salinity. This indicates that this Korean isolate of A. pacificum (Group IV) is a stenothermic and euryhaline species. In growth responses to changes in nutrient levels, enhanced growth rates and cell densities of A. pacificum (Group IV) were observed with additions of nitrate and phosphate. In particular, rapid uptakes of phosphate by A. pacificum (Group IV) were observed in experimental treatments, indicating that the increase in phosphate concentration could stimulate the growth of A. pacificum (Group IV).

거제도 장목항에서 분리한 Akashiwo sanguinea의 형태와 계통학적 특성을 명확히 하고, 여러 온도와 염분구배에 따른 성장조건을 파악하고자 하였다. A. sanguinea의 세포는 오각형이었고, 세포의 길이는 54.7~70.3 μm, 폭은 31.5~48.5 μm로 나타났다. 핵은 세포의 중심에 위치하였고, 엽록체는 황갈색으로 세포 전체에 퍼져있었다. 상추구는 알파벳 e 모양이었다. 계통분석 결과 장목항에서 분리한 본 배양주는 ribotype A에 포함되었다. 온도 및 염분구배에 따른 성장 실험은 5°C 이하의 온도를 제외한 모든 온 도구배에서 성장이 나타났다. 그리고, 최대성장속도는 온도 20°C, 염분 20 psu에서 0.50 day-1로 나타났고, 최대세포 밀도는 온도 25°C, 염분 30 psu에서 1,372 cells mL-1였다. 이 결과는 A. sanguinea가 가을철에 한국 연안에서 최대 증식을 보일 수 있다는 것을 나타낸다.

Recent increase of raw sequences generated by next generation sequencing (NGS) machines enabled re-analyzing raw sequences for diverse purposes: one is assembling organelle genome. One recent study completed the mitochondrial genomes of 14 ants from public raw sequences in subfamily Pseudomyrmecinae not having organelle genomes. Along with this approach, we have found four ant species of which genome papers were published and its raw sequences were open to public but its mitochondrial genome has not been assembled yet: Harpegnathos saltator and three Pogonomyrmex species (P. rugosus, P. anergismus, and P. colei). We assembled four complete mitochondrial genomes, presenting mitogenome of H. saltator 16,467 bp long and those of three Pogonomyrmex species above 21 kb long, ranking top among all known Hymenopteran mitogenomes. Four mitochondrial genomes contain 13 PCGs, 22 tRNAs, and 2 rRNAs, conserved as in all other insects. Phylogenomic tree based on partial or complete mitogneomes covering 26 genera provides insights of ant mitogenomic phylogeny and evolution.