The centralspindlin complex regulates cytokinesis and morphogenesis in the C. elegans spermatheca.

Organ morphogenesis needs orchestration of a series of cellular events, including cell division, cell shape change, cell rearrangement and cell death. Cytokinesis, the final step of cell division, is involved in the control of organ size, shape and function. Mechanistically, it is unclear how the molecules involved in cytokinesis regulate organ size and shape. Here, we demonstrate that the centralspindlin complex coordinates cell division and epithelial morphogenesis by regulating cytokinesis. Loss of the centralspindlin components CYK-4 and ZEN-4 disrupts cell division, resulting in altered cell arrangement and malformation of the Caenorhabditis elegans spermatheca. Further investigation revealed that most spermathecal cells undergo nuclear division without completion of cytokinesis. Germline mutant-based analyses suggest that CYK-4 regulates cytokinesis of spermathecal cells in a GTPase activator activity-independent manner. Spermathecal morphology defects can be enhanced by double knockdown of rho-1 and cyk-4, and partially suppressed by double knockdown of cdc-42 and cyk-4. Thus, the centralspindlin components CYK-4 and ZEN-4, together with RHO-1 and CDC-42, are central players of a signaling network that guides spermathecal morphogenesis by enabling completion of cytokinesis.

Generation and characterization of cardiac valve endothelial-like cells from human pluripotent stem cells.

The cardiac valvular endothelial cells (VECs) are an ideal cell source that could be used for making the valve organoids. However, few studies have been focused on the derivation of this important cell type. Here we describe a two-step chemically defined xeno-free method for generating VEC-like cells from human pluripotent stem cells (hPSCs). HPSCs were specified to KDR+/ISL1+ multipotent cardiac progenitors (CPCs), followed by differentiation into valve endothelial-like cells (VELs) via an intermediate endocardial cushion cell (ECC) type. Mechanistically, administration of TGFb1 and BMP4 may specify VEC fate by activating the NOTCH/WNT signaling pathways and previously unidentified targets such as ATF3 and KLF family of transcription factors. When seeded onto the surface of the de-cellularized porcine aortic valve (DCV) matrix scaffolds, hPSC-derived VELs exhibit superior proliferative and clonogenic potential than the primary VECs and human aortic endothelial cells (HAEC). Our results show that hPSC-derived valvular cells could be efficiently generated from hPSCs, which might be used as seed cells for construction of valve organoids or next generation tissue engineered heart valves.

Chitinimonas arctica sp. nov., isolated from Arctic tundra soil.

A Gram-stain-negative, rod-shaped, green-pigmented, aerobic and motile bacterium, strain R3-44T, was isolated from Arctic tundra soil. Stain R3-44T clustered closely with members of the genus Chitinimonas, which belongs to the family Burkholderiaceae, and showed the highest 16S rRNA sequence similarity to Chitinimonas naiadis AR2T (96.10%). Strain R3-44T grew optimally at pH 7.0, 28 °C and in the presence of 0-0.5 % (w/v) NaCl. The predominant respiratory isoprenoid quinone of strain R3-44T was identified as ubiquinone Q-8. The polar lipids consisted of phosphatidylglycerol, phosphatidylethanolamine, unidentified aminolipid and unidentified phospholipid. The main fatty acids were summed feature 3 (comprising C16 : 1 ω7c and/or C16 : 1 ω6c, 40.6 %) and C16 : 0 (29.3 %). The DNA G+C content of strain R3-44T was 60.8 mol%. On the basis of the evidence presented in this study, strain R3-44T represents a novel species of the genus Chitinimonas, for which the name Chitinimonas arctica sp. nov. is proposed, with the type strain R3-44T (=CCTCC AB 2010422T=KCTC 72602T).

Pseudolysobacter antarcticus gen. nov., sp. nov., isolated from soil in Fildes Peninsula, Antarctica.

A novel strain, designated AQ6-296T, was isolated from a soil sample collected in Fildes Peninsula, Antarctic. Cells were Gram-stain-negative, non-endospore-forming, non-motile, strictly aerobic and rod-shaped. Growth occurred at 4-28 °C (optimum, 20 °C) and at pH 6.0-7.0 (optimum, pH 7.0). NaCl was not obligatory for growth. Colonies were pale yellow after growth for 3 days at 20 °C on Reasoner's 2A agar. The strain was weakly positive for oxidase and the catalase test was negative. The only respiratory quinone was Q-8. The predominant cellular fatty acids were iso-C16 : 0, iso-C15 : 0, iso-C11 : 0 3OH, summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c) and summed feature 9 (comprising iso-C17 : 1ω9c and/or C16 : 010-methyl). The major polar lipids were phosphatidylethanolamine, unknown aminolipids, phosphatidylglycerol and diphosphatidylglycerol. The results of phylogenetic analysis based on 16S rRNA gene sequences (the highest similarity at 92.4 % to Lysobacter dokdonensis) indicated that strain AQ6-296T is within the family Xanthomonadaceae. The DNA G+C content of the type strain was 58.6 mol%. On the basis of phenotypic, chemotaxonomic and phylogenetic data, strain AQ6-296T is considered to represent a novel genus and species in the family Xanthomonadaceae, for which the name Pseudolysobacter antarcticus gen. nov., sp. nov. is proposed. The type strain is AQ6-296T (CCTCC AB 2016313T=KCTC 52744T).

Correction to: Hymenobacter oligotrophus sp. nov., isolated from a contaminated agar plate.

In the original publication, the deposit number of strain sh-6T was incorrectly published as "CCTCC AB 2016064" throughout the article.

Sphingomonas paeninsulae sp. nov., isolated from soil sampled at Fildes Peninsula, Antarctica.

Strain YZ-8T, isolated from soil sampled at Fildes Peninsula, Antarctica, was found to be a Gram-stain-negative, yellow-pigmented, oxidase- and catalase-positive, non-motile, non-spore-forming, rod-shaped and aerobic bacterium. Strain YZ-8T grewoptimally at pH 7.0 and 20 °C. Tolerance to NaCl was up to 0.3 % (w/v) with optimum growth in the absence of NaCl. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain YZ-8T belonged to the family Sphingomonas. Strain YZ-8T showed the highest sequence similarities to Sphingomonas molluscorum KMM 3882T (94.4 %), Sphingomonas oligophenolica JCM 12082T (94.4 %), Sphingomonas gotjawalisoli SN6-9T (94.3 %) and Sphingomonas aquatica W1-2-1T (94.3 %). The predominant respiratory isoprenoid quinone and polyamine components were identified as ubiquinone Q-10 and sym-homospermidine, respectively. In addition, carotenoid were also found. The polar lipid profile of the strain YZ-8T was found to contain one phosphatidylethanolamine, an unidentified phospholipid, one diphosphatidylglycerol, one phosphatidylglycerol, two sphingophosphonolipids, one phosphatidylcholine and two unidentified alkali-stable lipids. The G+C content of the genomic DNA was determined to be 58.8 mol%. The main fatty acids were summed feature 8 (comprising C18 : 1ω7c and/or C18 : 1ω6c; 35.4 %), summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c; 32.6 %) and C14 : 0 2-OH (7.7 %). On the basis of the evidence presented in this study, a novel species of the genus Sphingomonas, Sphingomonaspaeninsulae sp. nov., is proposed, with the type strain YZ-8T (=CCTCC AB 2017137T=LMG 31027T).

Deinococcus psychrotolerans sp. nov., isolated from soil on the South Shetland Islands, Antarctica.

A Gram-stain-negative, non-motile, strictly aerobic, coccus-shaped bacterium, designated S14-83T, was isolated from a soil sample collected from the South Shetland Islands of Antarctica. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the strain is a novel member of the genus Deinococcus, with Deinococcus alpinitundrae as its closest relative (96.1 % similarity). The DNA G+C content of the strain was 61.1 mol% and the major respiratory quinone was MK-8. Major cellular fatty acids were summed feature 3 (C16 : 1ω7c/C16 : 1ω6c) and C16 : 0. As well as containing glycophospholipid, aminophospholipids and glycolipid as major polar lipids, there were also some unknown polar lipids. The diagnostic diamino acid in the cell-wall peptidoglycan was ornithine, corroborating the assignment of the strain to the genus Deinococcus. Strain S14-83T was shown to be extremely resistant to gamma radiation (>10 kGy) and UV light (460 Jm-2). On the basis of phylogenetic, chemotaxonomic and phenotypic data presented here, strain S14-83T represents a novel species of the genus Deinococcus, for which the name Deinococcus psychrotolerans sp. nov. is proposed. The type strain is S14-83T (=CCTCC AB 2015449T= DSM 105285 T).

Hymenobacter oligotrophus sp. nov., isolated from a contaminated agar plate.

A taxonomic study of a Gram-stain negative, rod-shaped, motile, asporogenous, catalase- and oxidase-positive bacterium, sh-6T, forming pink-red colonies, isolated from a contaminated R2A plate in the laboratory was performed. Its optimum growth temperature was determined to be 28 °C in the absence of NaCl on R2A plates. On the basis of 16S rRNA gene sequence analysis, strain sh-6T belongs to the genus Hymenobacter and is closely related to Hymenobacter deserti ZLB-3T (95.05%), Hymenobacter paludis KBP-30T (94.96%), Hymenobacter coalescens WW84T (94.04%), Hymenobacter gummosus ANT-18T (93.38%), Hymenobacter ocellatus Myx2105T (93.70%), Hymenobacter jeollabukensis 1-3-3-8T (93.48%) and Hymenobacter koreensis GYR3077T (93.21%). Comparison of the genome of strain sh-6T and that of H. gummosus ANT-18T gave digital DNA-DNA hybridization and Average Nucleotide Identity values of 20.6% and 78.4%, respectively. The respiratory isoprenoid quinone and polyamine component were identified as MK-7 and sym-homospermidine, respectively. The major cellular fatty acids identified as iso-C15:0, summed feature 4 (iso-C17:1 I/anteiso B), iso-C16:0, iso-C17:0 3-OH and iso-C17:0. The major polar lipid of strain sh-6T determined to be phosphatidylethanolamine. The DNA G+C content was determined to be 60.5 mol%. On the basis of the evidence presented in this study, a novel species of the genus Hymenobacter, Hymenobacter oligotrophus sp. nov., is proposed, with the type strain sh-6T (= CCTCC AB 2016064T = KCTC 62345T).

Kaistella flava sp. nov., isolated from Antarctic tundra soil, and emended descriptions of Kaistella yonginensis, Kaistella jeonii, Kaistella antarctica and Kaistella chaponensis.

A rod-shaped, yellow-pigmented, Gram-stain-negative, non-motile and aerobic bacterium, designated 7-3AT, was isolated from soil from King George Island, maritime Antarctica, and subjected to a polyphasic taxonomic study. Growth occurred at 4-37 °C (optimum, 20°C) and at pH 5.0-9.0 (optimum, pH 7.0-8.0). Tolerance to NaCl was up to 4 % (w/v) with optimum growth in the absence of NaCl. The results of phylogenetic analysis based on 16S rRNA gene sequences indicated that strain 7-3AT represented a member of the family Flavobacteriaceae. Strain 7-3AT showed the highest sequence similarities with Kaistella yonginensis HMD 1043T (96.65 %), Kaistella carnis NCTC 13525T (96.53 %), Kaistella chaponensis DSM 23145T (96.27 %), Kaistella antarctica LMG 24720T (96.13 %) and Kaistella jeonii DSM 17048T (96.06 %). A whole genome-level comparison of 7-3AT with K. jeonii DSM 17048T, K. antarctica LMG 24720T, K. chaponensis DSM 23145T, and Kaistella palustris DSM 21579T revealed average nucleotide identity (ANI) values of 79.03, 82.25, 78.12, and 74.42 %, respectively. The major respiratory isoprenoid quinone was identified as MK-6 and a few ubiquinones Q-10 were identified. In addition, flexirubin-type pigments were absent. The polar lipid profile of 7-3AT was found to contain one phosphatidylethanolamine, six unidentified aminolipids (AL) and two unidentified lipids (L). The G+C content of the genomic DNA was determined to be 34.54 mol%. The main fatty acids were iso-C15 : 0, summed feature 9 (comprising iso-C17 : 1ω9c and/or C16 : 0 10-methyl), anteiso-C15 : 0, iso-C13 : 0 and summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c). On the basis of the evidence presented in this study, a novel species of the genus Kaistella, Kaistella flava sp. nov., is proposed, with the type strain 7-3AT (=CCTCC AB 2016141T= KCTC 52492T). Emended descriptions of Kaistella yonginensis, Kaistella jeonii, Kaistella antarctica and Kaistella chaponensis are also given.