Biology subjects

Bae, K.

Publications and source records attributed to Bae, K..

3 recordsLinked to original sources

bioRxiv2021

Diverse northern Asian and Jomon-related genetic structure discovered among socially complex Three Kingdoms period Gaya region Koreans

The genetic history of prehistoric and protohistoric Korean populations is not well understood due to the lack of ancient Korean genomes. Here, we report the first paleogenomic data from Korea; eight shotgun-sequenced genomes (0.7x[~]6.1x coverage) from two archeological sites in Gimhae: Yuha-ri shell mound and Daesung-dong tumuli, the most important funerary complex of the Gaya confederacy. All eight individuals are from the Korean Three Kingdoms period (4th-7th century CE), during which there is archaeological evidence of extensive trade connections with both northern (modern-day China) and eastern (modern-day Japan) kingdoms. All genomes are best modeled as an admixture between a northern-Chinese Iron Age genetic source and a Japanese-Jomon-related ancestry. The proportion of Jomon-related ancestry suggests the presence of two genetic groups within the population. The observed substructure indicates diversity among the Gaya population that is not related to either social status or sex. Teaser1,700-year-old genomes reveal the genetic diversity of ancient Koreans in the Gimhae region.

evolutionary biology↗

bioRxiv2019

Nanocomposite bioink exploits dynamic covalent bonds between nanoparticles and polysaccharides for precision bioprinting

The field of bioprinting has made significant recent progress towards engineering tissues with increasing complexity and functionality. It remains challenging, however, to develop bioinks with optimal biocompatibility and good printing fidelity. Here, we demonstrate enhanced printability of a polymer-based bioink based on dynamic covalent linkages between nanoparticles (NPs) and polymers, which retains good biocompatibility. Amine-presenting silica NPs (ca. 45 nm) were added to a polymeric ink containing oxidized alginate (OxA). The formation of reversible imine bonds between amines on the NPs and aldehydes of OxA lead to significantly improved rheological properties and high printing fidelity. In particular, the yield stress increased with increasing amounts of NPs (14.5 Pa without NPs, 79 Pa with 2 wt% NPs). In addition, the presence of dynamic covalent linkages in the gel provided improved mechanical stability over 7 days compared to ionically crosslinked gels. The nanocomposite ink retained high printability and mechanical strength, resulting in generation of centimetre-scale porous constructs and an ear structure with overhangs and high structural fidelity. Furthermore, the nanocomposite ink supported both in vitro and in vivo maturation of bioprinted gels containing chondrocytes. This approach based on simple oxidation can be applied to any polysaccharide, thus the widely applicability of the method is expected to advance the field towards the goal of precision bioprinting.

bioengineering↗

bioRxiv2017

Zebrafish yolk syncytial nuclei migrate along a dynamic microtubule network

In teleosts, the yolk syncytial layer is a multinucleate syncytium that functions as an extraembryonic signaling center to pattern the mesendoderm, coordinate morphogenesis and supply nutrients to the embryo. The zebrafish is an excellent system for studying this morphogenetically active tissue. The external yolk syncytial nuclei (e-YSN) undergo microtubule dependent epiboly movements that distribute the nuclei over the yolk. How e-YSN epiboly proceeds, and what role the yolk microtubule network plays is not understood but currently it is proposed that e-YSN are pulled vegetally as the microtubule network shortens from the vegetal pole. Data from our live imaging studies suggest that the yolk microtubule network is dismantled from the animal and vegetal regions and show that a region of stabilized microtubules forms before nuclear migration begins. e-YSN do not appear to be pulled vegetally but rather move along a dynamic microtubule network. We also show that overexpression of the KASH domain of Syne2a impairs e-YSN movement, implicating the LINC complex in e-YSN migration. This work provides new insights into the role of microtubules in morphogenesis of an extraembryonic tissue.\n\nSummary StatementAnalysis of yolk syncytial nuclear migration during zebrafish epiboly reveals that nuclei migrate along and largely beneath a dynamically yolk microtubule network.

developmental biology↗