Korean Ocean Research and Development Institute

About: Korean Ocean Research and Development Institute is a facility organization based out in Busan, South Korea. It is known for research contribution in the topics: Sea surface temperature & Gene. The organization has 1770 authors who have published 3032 publications receiving 50142 citations.

Observations of the Antarctic Circumpolar Current Over the Udintsev Fracture Zone, the Narrowest Choke Point in the Southern Ocean

Abstract: An up-to-date map of the Antarctic Circumpolar Current (ACC) fronts is constructed from the latest version of mean dynamic topography (MDT) from satellite altimetry and reveals the narrowest ACC width in the Udintsev Fracture Zone (UFZ), with the strongest concentration of the three major ACC fronts within a limited distance as short as 170 km, about 40% narrower than that at Drake Passage. At 144°W, at the entrance of the UFZ, which lies between the Pacific-Antarctic Ridge (PAR) and its eastwardly offset segment (offset PAR segment), there is a triple confluence of the Subantarctic Front, Polar Front, and Southern ACC Front. Downstream of this longitude, the Subantarctic Front progressively meanders northward over the relatively shallow offset PAR segment before channeling through the Eltanin Fracture Zone, thus diverging from the Polar Front which proceeds through the UFZ. In situ observations from two recent cruises at 144°W confirm the satellite altimetry-derived frontal circulation in the UFZ region and yield a baroclinic transport relative to the bottom of 113 × 10 6 m 3 /s, comparable to that through Drake Passage. The hydrographic sections show no Antarctic bottom water colder than 0.2°C. Characteristics of major water masses are described, and the implications for their potential downstream modifications at Drake Passage are discussed in terms of the meridional overturning circulation across the ACC. Mesoscale eddy activity with periods shorter than 90 days is predominantly concentrated in the immediate downstream area of the offset PAR segment, suggesting a substantial poleward eddy heat flux there.

Proposal of Algoriphagus vanfongensis sp. nov., transfer of members of the genera Hongiella Yi and Chun 2004 emend. Nedashkovskaya et al. 2004 and Chimaereicella Tiago et al. 2006 to the genus Algoriphagus, and emended description of the genus Algoriphagus Bowman et al. 2003 emend. Nedashkovskaya et al. 2004.

Abstract: A taxonomic study of a novel marine, heterotrophic, non-gliding, halotolerant and light-pink-pigmented bacterium was carried out using a polyphasic approach 16S rRNA gene sequence analysis revealed that strain KMM 6241(T) is a member of the phylum Bacteroidetes Strain KMM 6241(T) formed a cluster with the genera Algoriphagus, Chimaereicella and Hongiella with sequence similarities of 940-982 % Hongiella ornithinivorans was the closest relative of the novel isolate Comparative analysis of phenotypic, chemotaxonomic and genotypic characteristics of strain KMM 6241(T) and representatives of the genera Algoriphagus, Chimaereicella and Hongiella revealed many similar features Consequently, phylogenetic evidence supported by phenotypic and genotypic similarities support the transfer of members of the genera Chimaereicella and Hongiella to the genus Algoriphagus and the establishment of a novel species, Algoriphagus vanfongensis sp nov, with strain KMM 6241(T) (=DSM 17529(T)=KCTC 12716(T)) as the type strain

Improved Thermostability and Acetic Acid Tolerance of Escherichia coli via Directed Evolution of Homoserine o-Succinyltransferase

Abstract: In Escherichia coli, growth is limited at elevated temperatures mainly because of the instability of a single enzyme, homoserine o-succinyltransferase (MetA), the first enzyme in the methionine biosynthesis pathway. The metA gene from the thermophile Geobacillus kaustophilus cloned into the E. coli chromosome was found to enhance the growth of the host strain at elevated temperature (44°C), thus confirming the limited growth of E. coli due to MetA instability. In order to improve E. coli growth at higher temperatures, we used random mutagenesis to obtain a thermostable MetAE. coli protein. Sequencing of the thermotolerant mutant showed five amino acid substitutions: S61T, E213V, I229T, N267D, and N271K. An E. coli strain with the mutated metA gene chromosomally inserted showed accelerated growth over a temperature range of 34 to 44°C. We used the site-directed metA mutants to identify two amino acid residues responsible for the sensitivity of MetAE. coli to both heat and acids. Replacement of isoleucine 229 with threonine and asparagine 267 with aspartic acid stabilized the protein. The thermostable MetAE. coli enzymes showed less aggregation in vivo at higher temperature, as well as upon acetic acid treatment. The data presented here are the first to show improved E. coli growth at higher temperatures solely due to MetA stabilization and provide new knowledge for designing E. coli strains that grow at higher temperatures, thus reducing the cooling cost of bioprocesses.