Korea Research Institute of Bioscience and Biotechnology
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Orifice-based membrane fouling inhibition employing in-situ turbulence for efficient microalgae harvesting
No full textIn this study, a simple way of generating turbulence via the use of an orifice was developed for the purpose to mitigating membrane fouling in microalgae harvesting. When an orifice with given number of holes was installed at the inlet of a membrane module, vigorous turbulence was observed on the surface of the membrane, which caused to detach the cake layer and limit further formation of it. Experiments on Chlorella sp. HS-2 showed that the filtration efficiency increased up to 299% compared to the conventional cross-flow operation. Through computational fluid dynamics, it was proven that the orifice increased the shear stress over the membrane surface area from 0.7 Pa to maximum average shear stress of 52.3 Pa. With regards to the operation time, microalgae harvesting could be finished nearly 3 times faster with the orifice. Faster harvesting time implies more quantity at a given time, not to mention prevention of quality degradation associated with cell decay. Low power consumption with enhanced filtration performance supported that membrane filtration equipped with an orifice can offer a promising means for microalgae harvesting, in terms of surpassing effectiveness and simplicity.
Production of fermentable sugars from Chlorella sp. by solid-acid catalyst
No full textThe hydrolysis of microalgae Chlorella sp. via a solid acid catalyst was conducted in order to obtain fermentable sugars. To optimize the hydrolysis conditions, Box-Behnken design was used to construct the experimental setup. Results show that the highest fermentable sugar yield of 50.4% (25.2 g/L) was achieved using a reaction composed of 5% biomass and 40% solid acid catalyst loading (based on biomass), at a reaction temperature of 160 °C for 45 min. Moreover, under these conditions, only 1.16 g/L of 5-HMF and 0.12 g/L of levulinic acid were formed as by-products. Furthermore, at 12.5% biomass concentration, a 56.97 g/L (45.58%) high concentration of fermentable sugars was obtained. In conclusion, the utilization of microalgae and a solid acid catalyst for fermentable sugar production has a high possibility of applicability.
Anti-inflammatory and antioxidant effects of Carpesium cernuum L. methanolic extract in LPS-stimulated RAW 264.7 macrophages
No full textA hypernomic reaction or an abnormal inflammatory process could cause a series of diseases, such as cardiovascular disease, neurodegeneration, and cancer. Additionally, oxidative stress has been identified to induce severe tissue injury and inflammation. Carpesium cernuum L. (C. cernuum) is a Chinese folk medicine used for its anti-inflammatory, analgesic, and detoxifying properties. However, the underlying molecular mechanism of C. cernuum in inflammatory and oxidative stress conditions remains largely unknown. The aim of this study was to examine the effects of a methanolic extract of C. cernuum (CLME) on lipopolysaccharide- (LPS-) induced RAW 264.7 mouse macrophages and a sepsis mouse model. The data presented in this study indicated that CLME inhibited LPS-induced production of proinflammatory mediators such as nitric oxide (NO) and prostaglandin E2 (PGE2) in RAW 264.7 cells. CLME treatment also reduced reactive oxygen species (ROS) generation and enhanced the expression of heme oxygenase-1 (HO-1) protein in a dose-dependent manner in the LPS-stimulated RAW 264.7 cells. Moreover, CLME treatment abolished the nuclear translocation of nuclear factor-κB (NF-κB), enhanced the activation of nuclear factor-erythroid 2 p45-related factor 2 (Nrf2), and reduced the expression of extracellular signal-related kinase (ERK) and ERK kinase (MEK) phosphorylation in LPS-stimulated RAW 264.7 cells. These outcomes implied that CLME could be a potential antioxidant and anti-inflammatory agent.
Assessment of hand motor function in a non-human primate model of ischemic stroke
No full textIschemic stroke results from arterial occlusion and can cause irreversible brain injury. A non-human primate (NHP) model of ischemic stroke was previously developed to investigate its pathophysiology and for efficacy testing of therapeutic candidates; however, fine motor impairment remains to be well-characterized. We evaluated hand motor function in a cynomolgus monkey model of ischemic stroke. Endovascular transient middle cerebral artery occlusion (MCAO) with an angiographic microcatheter induced cerebral infarction. In vivo magnetic resonance imaging mapped and measured the ischemia-induced infarct lesion. In vivo diffusion tensor imaging (DTI) of the stroke lesion to assess the neuroplastic changes and fiber tractography demonstrated three-dimensional patterns in the corticospinal tract 12 weeks after MCAO. The hand dexterity task (HDT) was used to evaluate fine motor movement of upper extremity digits. The HDT was modified for a home cage-based training system, instead of conventional chair restraint training. The lesion was localized in the middle cerebral artery territory, including the sensorimotor cortex. Maximum infarct volume was exhibited over the first week after MCAO, which progressively inhibited ischemic core expansion, manifested by enhanced functional recovery of the affected hand over 12 weeks after MCAO. The total performance time decreased with increasing success rate for both hands on the HDT. Compensatory strategies and retrieval failure improved in the chronic phase after stroke. Our findings demonstrate the recovery of fine motor skill after stroke, and outline the behavioral characteristics and features of functional disorder of NHP stroke model, providing a basis for assessing hand motor function after stroke.
Clarification of undiagnosed ataxia using whole-exome sequencing with clinical implications
No full textBackground
Hereditary cerebellar ataxias exhibit heterogeneous phenotypes and genotypes. To date, advancement of next-generation sequencing technologies have identified many causative genes for ataxia in various population. In this study, whole-exome sequencing (WES) was utilized to explore the genetic cause of ataxia among Korean patients who remained undiagnosed following routine investigation.
Methods
Patients with ataxia were enrolled in this study. We excluded patients with acquired, degenerative, and trinucleotide repeat ataxias, such as spinocerebellar ataxia 1 (SCA1), SCA2, SCA3, SCA6, SCA7, SCA8, SCA17, Dentatorubral-pallidoluysian atrophy, and Friedreich ataxia. WES was performed. After basic filtering based on population databases, we then performed primary filtering to screen for known ataxia-associated genes, followed by expanded filtering customized for individual patients.
Results
We enrolled 77 ataxia patients from 68 families. Eighteen families had pathogenic or likely pathogenic variants in 14 different genes, including NEU1, APTX, SPG7, HTRA1, POLG2, SYNE1, CACNA1G, CACNA1A, ITPR1, AHI1, SPG11, ANO10, ATM, and C5orf42, resulting in a diagnostic yield of 26.5%. Hereditary spastic paraplegia was the most common diagnosis. Adult-onset ataxias and those without family history were frequently encountered. Variants of unknown significance were found in 14 (20.6%) families, some of which were highly probable from the clinical perspective.
Conclusion
Using WES, we explored the molecular etiology of ataxia in patients whom were not diagnosed through routine clinical investigation. This study revealed unexpected rare disorders as well as the known ataxia-associated genes in a Korean population.
A new experimental model to study human drug responses
No full textAccurate prediction of pharmacokinetic (PK) and pharmacodynamic (PD) characteristics is critical for drug development. Oral drugs are particularly difficult because they are absorbed by the intestine and metabolized in the liver before systemic metabolism in vivo; this is called the first-pass effect and is a critical factor for predicting oral bioavailability (BA). Here, we fabricated a new networking and circulating cell culture system (NCCS), mimicking the circulatory system and interaction of organs for studying the pharmacokinetic and pharmacodynamics of oral drugs in vitro. NCCS consisted of a micro-pump for circulating fluids, two types of multi-insert culture dishes for culturing different cell types, and an orbital shaker for mixing; flow rate and shaking-speed were controlled by weight-sensors and drivers. A first-pass effect test was performed using functionally differentiated HepaRG and Caco-2 cell lines, using a new modified spheroid forming unit (SFU) protocol. To verify the similarity of PK (first-pass effect) data of NCCS with the data from the human body, 15 reference drugs were chosen and their associated data were obtained by liquid chromatography-mass spectrometry analysis. NCCS generated absorption and metabolism data showed >70% similarity to human data respectively. NCCS can also be used to demonstrate species differences. Animal models are the primary basis for drug discovery, development, and testing. However, the weak correlation between humans and animals, particularly regarding absorption and metabolism, is a substantial limitation for the use of animal models. Here we compare human and mouse acetaminophen (APAP) metabolism using NCCS, and its application can be extended to assess cellular responses, such as efficacy and toxicity, simultaneously.
Fabrication of a polycaprolactone/alginate bipartite hybrid scaffold for osteochondral tissue using a three-dimensional bioprinting system
No full textOsteochondral defects, including damage to both the articular cartilage and the subchondral bone, are challenging to repair. Although many technological advancements have been made in recent years, there are technical difficulties in the engineering of cartilage and bone layers, simultaneously. Moreover, there is a great need for a valuable in vitro platform enabling the assessment of osteochondral tissues to reduce pre-operative risk. Three-dimensional (3D) bioprinting systems may be a promising approach for fabricating human tissues and organs. Here, we aimed to develop a polycaprolactone (PCL)/alginate bipartite hybrid scaffold using a multihead 3D bioprinting system. The hybrid scaffold was composed of PCL, which could improve the mechanical properties of the construct, and alginate, encapsulating progenitor cells that could differentiate into cartilage and bone. To differentiate the bipartite hybrid scaffold into osteochondral tissue, a polydimethylsiloxane coculture system for osteochondral tissue (PCSOT) was designed and developed. Based on evaluation of the biological performance of the novel hybrid scaffold, the PCL/alginate bipartite scaffold was successfully fabricated; importantly, our findings suggest that this PCSOT system may be applicable as an in vitro platform for osteochondral tissue engineering.
Peroxiredoxin 4 attenuates glutamate-induced neuronal cell death through inhibition of endoplasmic reticulum stress
No full textHigh concentrations of glutamate induce neurotoxicity by eliciting reactive oxygen species (ROS) generation and intracellular Ca2+ influx. The disruption of Ca2+ homeostasis in the endoplasmic reticulum (ER) evokes ER stress, ultimately resulting in neuronal dysfunction. Additionally, glutamate participates in the development of neurodegenerative diseases, such as Alzheimer’s and Parkinson’s diseases. Peroxiredoxins (Prxs) are members of a family of antioxidant enzymes that protect cells from neurotoxic factor-induced apoptosis by scavenging hydrogen peroxide (H2O2). Prx4 is located in the ER and controls the redox condition within the ER. The present study investigated the protective effects of Prx4 against glutamate-induced neurotoxicity linked to ER stress. HT22 cells in which Prx4 was either overexpressed or silenced were used to elucidate the protective role of Prx4 against glutamate toxicity. The expression of Prx4 in HT22 cells was significantly increased in response to glutamate treatment, while ROS scavengers and ER chemical chaperones reduced Prx4 levels. Moreover, Prx4 overexpression reduces glutamate-induced apoptosis of HT22 cells by inhibiting ROS formation, Ca2+ influx, and ER stress. Therefore, we conclude that Prx4 has protective effects against glutamate-induced HT22 cell damage. Collectively, these results suggest that Prx4 could contribute to the treatment of neuronal disorders.
TGFam-Finder: a novel solution for target-gene family annotation in plants
No full textWhole-genome annotation error that omits essential protein-coding genes hinders further research. We developed Target Gene Family Finder (TGFam-Finder), an alternative tool for the structural annotation of protein-coding genes containing target domain(s) of interest in plant genomes. TGFam-Finder took considerably reduced annotation run-time and improved accuracy compared to conventional annotation tools. Large-scale re-annotation of 50 plant genomes identified an average of 150, 166 and 86 additional far-red-impaired response 1, nucleotide-binding and leucine-rich-repeat, and cytochrome P450 genes, respectively, that were missed in previous annotations. We detected significantly higher number of translated genes in the new annotations using mass spectrometry data from seven plant species compared to previous annotations. TGFam-Finder along with the new gene models can provide an optimized platform for comprehensive functional, comparative, and evolutionary studies in plants.