Korea Research Institute of Bioscience and Biotechnology
KRIBB Open Access RepositoryNot a member yet
15834 research outputs found
Sort by
Development of a novel composite film based on polyurethane and defatted Chlorella biomass: Physical and functional characterization
No full textNovel composite films made of polyurethane (PU) and defatted Chlorella biomass (DCB) at different mass proportions (10？70 wt%) were prepared using polyethylene glycol (PEG) as a model polyol and hexamethylene diisocyanate (HMDI) as a coupling agent. Increasing DCB content led to a respective increase in tensile strength and elongation at break of the composites in the range of 33.9？116% and 69.6？248%, compared to the neat PU-PEG film. As confirmed by Fourier transform infrared and scanning electron microscopy analysis, such improvement in mechanical properties can be attributed to the establishment of hydrogen bonds and other molecular interactions between isocyanate groups of PEG-HMDI prepolymer and hydroxyl groups of DCB biofiller along with the uniform distribution of the incorporated DCB into the PU-PEG based matrix. DCB incorporation at the highest content of 70% increased both antioxidant activity and bulk hydrophilicity of the composites by more than 69.3 and 85.0%, respectively, compared to the neat PU-PEG.
Bioprospecting of exopolysaccharide from marine Sphingobium yanoikuyae BBL01: production, characterization, and metal chelation activity
No full textIn the present study, an exopolysaccharide (EPS)-producing bacterial strain was isolated from the Eastern Sea (Sokcho Beach) of South Korea and identified as Sphingobium yanoikuyae BBL01. Media optimization was performed using response surface design, and a yield of 2.63 ± 0.02 g/L EPS was achieved. Purified EPS produced using lactose as the main carbon source was analyzed by GC-MS and found to be composed of α-D-xylopyranose (28.6 ± 2.0%), β-D-glucopyranose (21.0 ± 1.6%), α-D-mannopyranose (18.5 ± 1.2%), β-d-mannopyranose (13.1 ± 1.4%), β-D-xylopyranose (10.2 ± 2.1%), α-d-talopyranose (5.9 ± 1.1%), and β-d-galacturonic acid (2.43 ± 0.8%). Interestingly, different carbon sources (glucose, galactose, glycerol, lactose, sucrose, and xylose) showed no effect on EPS monomer composition, with a slight change in the mass percentage of various monosaccharides. Purified EPS was stable up to 233 °C, indicating its possible suitability as a thickening and gelling agent for food-related applications. EPS also showed considerable emulsifying, flocculating, free-radical scavenging, and metal-complexion activity, suggesting various biotechnological applications.
A clofazimine-containing regimen confers improved treatment outcomes in macrophages and in a murine model of chronic progressive pulmonary infection caused by the Mycobacterium avium complex
No full textTreatment outcomes using the standard regimen (a macrolide, ethambutol, and rifampicin) for Mycobacterium avium complex-pulmonary disease (MAC-PD) remain unsatisfactory. Thus, improved treatment regimens for MAC-PD are required. Clofazimine has recently been revisited as an effective drug against mycobacterial infection. We performed a comparison between the standard regimen and an alternative regimen (replacing the rifampicin of the standard regimen with clofazimine) based on the intracellular anti-MAC activities of the individual drugs in a murine model of chronic progressive MAC-pulmonary infection (MAC-PI). The intracellular anti-MAC activities of the individual drugs and their combinations in murine bone marrow-derived macrophages (BMDMs) were determined. The treatment efficacies of the standard and clofazimine-containing regimens were evaluated in mice chronically infected with M. avium by initiating 2- and 4-week treatment at 8 weeks post-infection. Bacterial loads in the lung, spleen, and liver were assessed along with lung inflammation. Insufficient intracellular anti-MAC activity of rifampicin in BMDMs was recorded despite its low in vitro minimum inhibitory concentrations (MICs), whereas optimal intracellular killing activity against all tested MAC strains was achieved with clofazimine. Compared to the standard regimen, the clofazimine-containing regimen significantly reduced CFUs in all organs and achieved marked reductions in lung inflammation. The replacement of rifampicin with clofazimine in the treatment regimen resulted in more favorable outcomes in an animal model of chronic progressive MAC-PI. Intriguingly, 2 weeks of treatment with the clofazimine-containing regimen reduced bacterial loads more effectively than 4 weeks of treatment with the standard regimen in M. avium-infected mice. Thus, the clofazimine-containing regimen also had a treatment-shortening effect.
Ticagrelor does not affect left ventricular remodeling following acute myocardial ischemia
No full textBackground: Despite ticagrelor’s proven superiority to clopidogrel in treating patients with acute coronary syndrome, it is unclear whether its actions are mediated by antiplatelet inhibition or by some other pleotropic effect. In this study, we used a porcine model of acute myocardial infarction (AMI) to evaluate the efficacy of ticagrelor administered at a similar level of platelet inhibition to that seen with clopidogrel.
Methods: Twenty pigs were grouped according to the P2Y12-receptor inhibitors (ticagrelor or clopidogrel). Platelet inhibition was monitored by measuring adenosine diphosphate - induced platelet aggregation. A chronic ischemic heart model was artificially generated by embolization of the middle left anterior descending coronary artery. Animals received a maintenance dose of the antiplatelet agents. Two-dimensional echocardiography was performed on the surviving animals 2 weeks later.
Results: Both 180 mg ticagrelor and 600 mg clopidogrel exerted a significant and consistent antiplatelet effect showing platelet aggregation inhibition of 50.7±22.9% and 45.5±21.0%, respectively, p=0.614), which persisted for up to 2 weeks. However, no significant differences were observed in ventricular arrhythmia (40% vs. 50%, respectively; p=0.886). The ejection fraction measured 2 weeks after surgery was 44.6±7.4% in the ticagrelor group and 36.9±5.7% in the clopidogrel group (p=0.091).
Conclusions: In a chronic ischemic heart failure model with a similar level of platelet inhibition, ticagrelor was no better than clopidogrel in reducing mortality and improving cardiac function.
The nuclear receptor ESRRA protects from kidney disease by coupling metabolism and differentiation
No full textKidney disease is poorly understood because of the organ's cellular diversity. We used single-cell RNA sequencing not only in resolving differences in injured kidney tissue cellular composition but also in cell-type-specific gene expression in mouse models of kidney disease. This analysis highlighted major changes in cellular diversity in kidney disease, which markedly impacted whole-kidney transcriptomics outputs. Cell-type-specific differential expression analysis identified proximal tubule (PT) cells as the key vulnerable cell type. Through unbiased cell trajectory analyses, we show that PT cell differentiation is altered in kidney disease. Metabolism (fatty acid oxidation and oxidative phosphorylation) in PT cells showed the strongest and most reproducible association with PT cell differentiation and disease. Coupling of cell differentiation and the metabolism was established by nuclear receptors (estrogen-related receptor alpha [ESRRA] and peroxisomal proliferation-activated receptor alpha [PPARA]) that directly control metabolic and PT-cell-specific gene expression in mice and patient samples while protecting from kidney disease in the mouse model.
New polyenes from the marine-derived fungus Talaromyces cyanescens with anti-neuroinflammatory and cytotoxic activities
No full textThree new polyene compounds, talacyanols A-C (1-3), along with two known compounds, ramulosin (4) and eurothiocin A (5), were isolated from the marine fungus Talaromyces cyanescens derived from a seaweed Caulerpa sp. Structures of 1-5 were established by one-dimensional and two-dimensional (1D/2D) NMR, HR-ESIMS, and the modified Mosher’s methods, as well as comparison with previously reported literature data. All the compounds (1？5) were tested for their in vitro cytotoxic and anti-neuroinflammatory activities. Among them, 1 showed moderate cytotoxic activity against a panel of cancer cell lines (HCT-15, NUGC-3, NCI-H23, ACHN, PC-3, and MDA-MB-231) with GI50 values ranging from 44.4 to 91.6 μM, whereas compounds 2 and 5 exhibited anti-neuroinflammatory effect without cytotoxicity against all the tested cell lines.
Identifying genome-wide off-target sites of CRISPR RNA-guided nucleases and deaminases with Digenome-seq
No full textDigested genome sequencing (Digenome-seq) is a highly sensitive, easy-to-carry-out, cell-free method for experimentally identifying genome-wide off-target sites of programmable nucleases and deaminases (also known as base editors). Genomic DNA is digested in vitro using clustered regularly interspaced short palindromic repeats ribonucleoproteins (RNPs; plus DNA-modifying enzymes to cleave both strands of DNA at sites containing deaminated base products, in the case of base editors) and subjected to whole-genome sequencing (WGS) with a typical sequencing depth of 30×. A web-based program is available to map in vitro cleavage sites corresponding to on- and off-target sites. Chromatin DNA, in parallel with histone-free genomic DNA, can also be used to account for the effects of chromatin structure on off-target nuclease activity. Digenome-seq is more sensitive and comprehensive than cell-based methods for identifying off-target sites. Unlike other cell-free methods, Digenome-seq does not involve enrichment of DNA ends through PCR amplification. The entire process other than WGS, which takes ~1-2 weeks, including purification and preparation of RNPs, digestion of genomic DNA and bioinformatic analysis after WGS, takes about several weeks.
Current challenges associated with the use of human induced pluripotent stem cell-derived organoids in regenerative medicine
No full textInnovative advances in stem cell research have resulted in the development of organoids, which are widely used as in vitro models of human organ development and for disease. The long-term goals of scientists include the generation of high-quality organoids with properties like those of native organs, and to expand their use to a variety of applications such as drug discovery and organoid-based cell therapy. In particular, the combination of human induced pluripotent stem cell (iPSC)-derived organoids with the recently developed genome engineering, biotechnology serve as an attractive platform in precision medicine. This review briefly summarizes the generation of organoids derived mostly from iPSCs without ethical issues, and describes the applications and technological advances of organoids under their differentiation and culture conditions. We also discuss the approaches to improve the organoid models, and how organoids can recapitulate mature organ systems of the human body for regenerative medicine. Finally, the future perspectives and remaining challenges in the field have been discussed to provide a better understanding of the potential applications of organoids.
Nc886, a novel suppressor of the type I interferon response upon pathogen intrusion
No full textInterferons (IFNs) are a crucial component in the innate immune response. Especially the IFN-β signaling operates in most cell types and plays a key role in the first line of defense upon pathogen intrusion. The induction of IFN-β should be tightly controlled, because its hyperactivation can lead to tissue damage or autoimmune diseases. Activation of the IFN-β promoter needs Interferon Regulatory Factor 3 (IRF3), together with Nuclear Factor kappa-light-chain-enhancer of activated B cells (NF-κB) and Activator Protein 1 (AP-1). Here we report that a human noncoding RNA, nc886, is a novel suppressor for the IFN-β signaling and inflammation. Upon treatment with several pathogen-associated molecular patterns and viruses, nc886 suppresses the activation of IRF3 and also inhibits NF-κB and AP-1 via inhibiting Protein Kinase R (PKR). These events lead to decreased expression of IFN-β and resultantly IFN-stimulated genes. nc886′s role might be to restrict the IFN-β signaling from hyperactivation. Since nc886 expression is regulated by epigenetic and environmental factors, nc886 might explain why innate immune responses to pathogens are variable depending on biological settings.
Nocardioides cynanchi sp. nov., isolated from soil of rhizosphere of Cynanchum wilfordii
No full textA novel actinobacterial strain, SB3-45T, was isolated from soil of Cynanchum wilfordii rhizosphere, Jaecheon-si, Chungcheongbuk-do, Republic of Korea. Strain SB3-45T, was Gram-stain-positive, aerobic and coccoid to short rod-shaped bacterium. Growth occurred at 4？37？°C (optimum 28？°C), pH 5？8 (optimum pH 7) and 0？2.5？%？NaCl (optimum 0%). Phylogenetic analysis based on 16S rRNA gene sequence showed that strain SB3-45T belonged to the genus Nocardioides and was closely related to Nocardioides opuntiae OS-21T (96.2%) and Nocardioides panacihumi Gsoil 616T (95.9%). ll-DAP as the diamino acid in the peptidoglycan and the menaquinone MK-8(H4) as the predominant isoprenoid quinone were detected. The polar lipids of strain SB3-45T were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and unidentified phospholipid. The major cellular fatty acids (>5%) of strain SB3-45T were iso-C16？:？0, C18？:？1？ω9c and C17？:？0. Based on phylogenetic, physiological and chemotaxonomic characteristics, strain SB3-45T represents a novel species of the genus Nocardioides, for which the name Nocardioides cynanchi sp.nov. is proposed. The type strain is SB3-45T (=KCTC 49133T=NBRC 114107T).