The complete mitochondrial genome of Haustorioides koreanus Jo, 1988 (Crustacea: Amphipoda: Dogielinotidae).

The mitochondrial genome of a dogielinotid amphipod, Haustorioides koreanus, was completely sequenced for the first time. The total mitogenome length of H. koreanus was 14,839 bp with 13 protein-coding genes, two ribosomal RNA genes, and 22 transfer RNA genes. The phylogenetic tree confirmed that H. koreanus belongs to the families Hyalellidae in the same clade and to the suborder Senticaudata within Amphipoda. This is the first record of the complete mitochondrial genome sequence of the family Dogielinotidae.

Integrative description of Diosaccus koreanus sp. nov. (Hexanauplia, Harpacticoida, Miraciidae) and integrative information on further Korean species.

A new species of Diosaccus Boeck, 1873 (Arthropoda, Hexanauplia, Harpacticoida) was recently discovered in Korean waters. The species was previously recognized as D. ezoensis Itô, 1974 in Korea but, here, is described as a new species, D. koreanus sp. nov., based on the following features: 1) second inner seta on exopod of fifth thoracopod apparently longest in female, 2) outer margin of distal endopodal segment of second thoracopod ornamented with long setules in male, 3) caudal seta VII located halfway from base of rami (vs. on anterior extremity in D. ezoensis), and 4) sixth thoracopod with three setae in female (vs. 2 setae in D. ezoensis). In addition, there is also a mitochondrial COI sequence difference of more than 19.93% with D. ezoensis registered in NCBI. A key to Diosaccus species of the world is also provided, and new morphological features and DNA sequences are presented for two other harpacticoid species, Parathalestris verrucosa Itô, 1970 and Peltidium quinquesetosum Song & Yun, 1999. In order to clearly identify harpacticoids at the species level, both morphological and DNA sequence characteristics should be considered.

The complete mitochondrial genome of Undinula vulgaris (Dana, 1849) (Crustacea: Calanoida: Calanidae).

The present study reports, for the first time, the complete mitochondrial genome (mitogenome) of Undinula vulgaris. The total mitogenome length of U. vulgaris was 15,303 bp with 13 protein-coding genes (PCGs), 2 ribosomal RNAs (rRNAs), 22 transfer RNAs (tRNAs), and 1 non-coding region. Phylogenetic analysis showed that U. vulgaris belonged to the same family. This is the second report of the complete mitogenome sequence of the family Calanidae.

Akinete germination chamber: An experimental device for cyanobacterial akinete germination and plankton emergence.

Understanding how algal resting cells (e.g. akinetes) germinate and what factors influence their germination rate is crucial for elucidating the development of algal blooms and their succession. While laboratory studies have demonstrated algal germination rate and some key factors affecting the germination, the use of artificially induced akinetes and/or removal of the sediments are obviously limiting in simulating the natural environment when designing such controlled experiments. This study introduce a laboratory Akinete Germination Chamber (AGC) that facilitates research for cyanobacterial akinete germination and emergence in an environment similar to natural conditions while minimizing sediment disturbance. The fundamental difference between AGC method and the conventional microplate method is that AGC incorporates the substrate from the natural environment whereas the microplate method does not employ sediment. Therefore, authors of this study assume that the characteristics of akinete germination between the two methods differ because the sediment influences the germination environment. The present study developed the AGC method as an efficient tool to understand harmful cyanobacterial bloom formation. For validation of the AGC method, this study evaluated akinete germination of Dolichospermum circinale (Anabaena circinalis) with different temperature and nutrient condition and then compared the results with those generated by conventional methods The results showed a marked difference in the maximal germination rate between two methods (78% and 35% in the AGC and the microplate, respectively; p < 0.05) at optimum germination temperature (25 °C for both the AGC and the microplate). The nutrient effect also demonstrated clear difference (p < 0.01) in the germination rate between two methods; 88%, 68% and 78% in the AGC and 15%, 20% and 15% in the microplate with -N+P, +N-P, and +N+P condition of CB medium, respectively. Importantly, both DW and -N-P treatments in the AGC induced a little germination of akinete (4.2 ±â€¯1.4% and 5.0 ±â€¯7.1%, respectively), whereas no germination was occurred in the DW treatment in the microplate, suggesting a possible positive effect of sediment on akinete germination. With these results, this study suspects that these differences were largely attributable to natural sediment. Also sediment-accompanied properties, possibly such as nutrient availability, heat budget, micronutrients, and bacteria might have some potential effects on akinete germination. The AGC method can overcome the limitations of the conventional microplate method, and that it is applicable in studies on pelagic-benthic coupling.

The complete mitochondrial genome of Gymnogobius heptacanthus (Perciformes, gobiidae).

Gymnogobius heptacanthus is a small intertidal species belonging to the family Gobiidae. Herein, we report the first sequencing and assembly of the complete mitochondrial genome of G. heptacanthus. The complete mitochondrial genome is 16,529 bp long and has the typical vertebrate mitochondrial gene arrangement, consisting of 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and a control region. Phylogenetic analysis using mitochondrial genomes of 12 species showed that G. heptacanthus is clustered with G. urotaenia and G. petschiliensis and rooted with other Gobiidae species. This mitochondrial genome provides potentially important resources for addressing taxonomic issues and studying molecular evolution.

The complete mitochondrial genome of Arctic Calanus hyperboreus (Copepoda, Calanoida) reveals characteristic patterns in calanoid mitochondrial genome.

Copepoda is the most diverse and abundant group of crustaceans, but its phylogenetic relationships are ambiguous. Mitochondrial (mt) genomes are useful for studying evolutionary history, but only six complete Copepoda mt genomes have been made available and these have extremely rearranged genome structures. This study determined the mt genome of Calanus hyperboreus, making it the first reported Arctic copepod mt genome and the first complete mt genome of a calanoid copepod. The mt genome of C. hyperboreus is 17,910 bp in length and it contains the entire set of 37 mt genes, including 13 protein-coding genes, 2 rRNAs, and 22 tRNAs. It has a very unusual gene structure, including the longest control region reported for a crustacean, a large tRNA gene cluster, and reversed GC skews in 11 out of 13 protein-coding genes (84.6%). Despite the unusual features, comparing this genome to published copepod genomes revealed retained pan-crustacean features, as well as a conserved calanoid-specific pattern. Our data provide a foundation for exploring the calanoid pattern and the mechanisms of mt gene rearrangement in the evolutionary history of the copepod mt genome.

A DO- and pH-based early warning system of nitrification inhibition for biological nitrogen removal processes.

In Korea, more than 80% of municipal wastewater treatment plants (WWTPs) with capacities of 500 m3·d-1 or more are capable of removing nitrogen from wastewater through biological nitrification and denitrification processes. Normally, these biological processes show excellent performance, but if a toxic chemical is present in the influent to a WWTP, the biological processes (especially, the nitrification process) may be affected and fail to function normally; nitrifying bacteria are known very vulnerable to toxic substances. Then, the toxic compound as well as the nitrogen in wastewater may be discharged into a receiving water body without any proper treatment. Moreover, it may take significant time for the process to return back its normal state. In this study, a DO- and pH-based strategy to identify potential nitrification inhibition was developed to detect early the inflow of toxic compounds to a biological nitrogen removal process. This strategy utilizes significant changes observed in the oxygen uptake rate and the pH profiles of the mixed liquor when the activity of nitrifying bacteria is inhibited. Using the strategy, the toxicity from test wastewater with 2.5 mg·L-1 Hg2+, 0.5 mg·L-1 allythiourea, or 0.25 mg·L-1 chloroform could be successfully detected.

The perception of syllable affiliation of singleton stops in repetitive speech.

Stetson (1951) noted that repeating singleton coda consonants at fast speech rates makes them be perceived as onset consonants affiliated with a following vowel. The current study documents the perception of rate-induced resyllabification, as well as what temporal properties give rise to the perception of syllable affiliation. Stimuli were extracted from a previous study of repeated stop + vowel and vowel + stop syllables (de Jong, 2001a, 2001b). Forced-choice identification tasks show that slow repetitions are clearly distinguished. As speakers increase rate, they reach a point after which listeners disagree as to the affiliation of the stop. This pattern is found for voiced and voiceless consonants using different stimulus extraction techniques. Acoustic models of the identifications indicate that the sudden shift in syllabification occurs with the loss of an acoustic hiatus between successive syllables. Acoustic models of the fast rate identifications indicate various other qualities, such as consonant voicing, affect the probability that the consonants will be perceived as onsets. These results indicate a model of syllabic affiliation where specific juncture-marking aspects of the signal dominate parsing, and in their absence other differences provide additional, weaker cues to syllabic affiliation.