Reproducible Polybutylene Succinate (PBS)-Degrading Artificial Consortia by Introducing the Least Type of PBS-Degrading Strains.

Polybutylene succinate (PBS) stands out as a promising biodegradable polymer, drawing attention for its potential as an eco-friendly alternative to traditional plastics due to its biodegradability and reduced environmental impact. In this study, we aimed to enhance PBS degradation by examining artificial consortia composed of bacterial strains. Specifically, Terribacillus sp. JY49, Bacillus sp. JY35, and Bacillus sp. NR4 were assessed for their capabilities and synergistic effects in PBS degradation. When only two types of strains, Bacillus sp. JY35 and Bacillus sp. NR4, were co-cultured as a consortium, a notable increase in degradation activity toward PBS was observed compared to their activities alone. The consortium of Bacillus sp. JY35 and Bacillus sp. NR4 demonstrated a remarkable degradation yield of 76.5% in PBS after 10 days. The degradation of PBS by the consortium was validated and our findings underscore the potential for enhancing PBS degradation and the possibility of fast degradation by forming artificial consortia, leveraging the synergy between strains with limited PBS degradation activity. Furthermore, this study demonstrated that utilizing only two types of strains in the consortium facilitates easy control and provides reproducible results. This approach mitigates the risk of losing activity and reproducibility issues often associated with natural consortia.

Versatile human cardiac tissues engineered with perfusable heart extracellular microenvironment for biomedical applications.

Engineered human cardiac tissues have been utilized for various biomedical applications, including drug testing, disease modeling, and regenerative medicine. However, the applications of cardiac tissues derived from human pluripotent stem cells are often limited due to their immaturity and lack of functionality. Therefore, in this study, we establish a perfusable culture system based on in vivo-like heart microenvironments to improve human cardiac tissue fabrication. The integrated culture platform of a microfluidic chip and a three-dimensional heart extracellular matrix enhances human cardiac tissue development and their structural and functional maturation. These tissues are comprised of cardiovascular lineage cells, including cardiomyocytes and cardiac fibroblasts derived from human induced pluripotent stem cells, as well as vascular endothelial cells. The resultant macroscale human cardiac tissues exhibit improved efficacy in drug testing (small molecules with various levels of arrhythmia risk), disease modeling (Long QT Syndrome and cardiac fibrosis), and regenerative therapy (myocardial infarction treatment). Therefore, our culture system can serve as a highly effective tissue-engineering platform to provide human cardiac tissues for versatile biomedical applications.

Positive effect of phasin in biohydrogen production of non polyhydroxybutyrate-producing Clostridium acetobutylicum ATCC 824.

In this study, the goal was to enhance the tolerance of Clostridium acetobutylicum ATCC 824 to biomass-based inhibitory compounds for biohydrogen production and evaluate various known genes that enhance the production of biochemicals in various hosts. The introduction of phaP, the major polyhydroxyalkanoate granule-associated protein that has been reported as a chaperone-like protein resulted in increased tolerance to inhibitors and leads to higher levels of hydrogen production, cell growth, and glucose consumption in the presence of these inhibitors. It was observed that the introduction of phaP led to an increase in the transcription of the hydrogenase gene, whereas transcription of the chaperone functional genes decreased compared to the wild type. Finally, the introduction of phaP could significantly enhance biohydrogen production by 2.6-fold from lignocellulosic hydrolysates compared to that of wild type. These findings suggested that the introduction of phaP could enhance growth and biohydrogen production, even in non-polyhydroxyalkanoate-producing strains.

Unveiling the inhibition mechanism of Clostridioides difficile by Bifidobacterium longum via multiomics approach.

Antibiotic-induced gut microbiota disruption constitutes a major risk factor for Clostridioides difficile infection (CDI). Further, antibiotic therapy, which is the standard treatment option for CDI, exacerbates gut microbiota imbalance, thereby causing high recurrent CDI incidence. Consequently, probiotic-based CDI treatment has emerged as a long-term management and preventive option. However, the mechanisms underlying the therapeutic effects of probiotics for CDI remain uninvestigated, thereby creating a knowledge gap that needs to be addressed. To fill this gap, we used a multiomics approach to holistically investigate the mechanisms underlying the therapeutic effects of probiotics for CDI at a molecular level. We first screened Bifidobacterium longum owing to its inhibitory effect on C. difficile growth, then observed the physiological changes associated with the inhibition of C. difficile growth and toxin production via a multiomics approach. Regarding the mechanism underlying C. difficile growth inhibition, we detected a decrease in intracellular adenosine triphosphate (ATP) synthesis due to B. longum-produced lactate and a subsequent decrease in (deoxy)ribonucleoside triphosphate synthesis. Via the differential regulation of proteins involved in translation and protein quality control, we identified B. longum-induced proteinaceous stress. Finally, we found that B. longum suppressed the toxin production of C. difficile by replenishing proline consumed by it. Overall, the findings of the present study expand our understanding of the mechanisms by which probiotics inhibit C. difficile growth and contribute to the development of live biotherapeutic products based on molecular mechanisms for treating CDI.

Multiomics analysis reveals the biological effects of live Roseburia intestinalis as a high-butyrate-producing bacterium in human intestinal epithelial cells.

Butyrate-producing bacteria play a key role in human health, and recent studies have triggered interest in their development as next-generation probiotics. However, there remains limited knowledge not only on the identification of high-butyrate-producing bacteria in the human gut but also in the metabolic capacities for prebiotic carbohydrates and their interaction with the host. Herein, it was discovered that Roseburia intestinalis produces higher levels of butyrate and digests a wider variety of prebiotic polysaccharide structures compared with other human major butyrate-producing bacteria (Eubacterium rectale, Faecalibacterium prausnitzii, and Roseburia hominis). Moreover, R. intestinalis extracts upregulated the mRNA expression of tight junction proteins (TJP1, OCLN, and CLDN3) in human intestinal epithelial cells more than other butyrate-producing bacteria. R. intestinalis was cultured with human intestinal epithelial cells in the mimetic intestinal host-microbe interaction coculture system to explore the health-promoting effects using multiomics approaches. Consequently, it was discovered that live R. intestinalis only enhances purine metabolism and the oxidative pathway, increasing adenosine triphosphate levels in human intestinal epithelial cells, but that heat-killed bacteria had no effect. Therefore, this study proposes that R. intestinalis has potentially high value as a next-generation probiotic to promote host intestinal health.

Generation of a novel monoclonal antibody against inflammatory biomarker S100A8 using hybridoma technology.

OBJECTIVES: S100A8 is highly expressed in several inflammatory and oncological conditions. To address the current lack of a reliable and sensitive detection method for S100A8, we generated a monoclonal antibody with a high binding affinity to human S100A8 to enable early disease diagnosis. RESULTS: A soluble recombinant S100A8 protein with a high yield and purity was produced using Escherichia coli. Next, mice were immunized with recombinant S100A8 to obtain anti-human S100A8 monoclonal antibodies using hybridoma technology. Lastly, the high binding activity of the antibody was confirmed and its sequence was identified. CONCLUSIONS: This method, including the production of antigens and antibodies, will be useful for the generation of hybridoma cell lines that produce anti-S100A8 monoclonal antibodies. Moreover, the sequence information of the antibody can be used to develop a recombinant antibody for use in various research and clinical applications.

Enhancement of polyhydroxybutyrate production by introduction of heterologous phasin combination in Escherichia coli.

Phasin is a surface-binding protein of polyhydroxyalkanoate (PHA) granules that is encoded by the phaP gene. As its expression increases, PHA granules become smaller, to increase their surface area, and are densely packed inside the cell, thereby increasing the PHA content. A wide range of PHA-producing bacteria have phaP genes; however, their PHA productivity differs, although they are derived from the cognate bacterial host cell. Modulating phasin expression could be a new strategy to enhance PHA production. This study aimed to characterize the effect of heterologous phasins on the reconstitution of E. coli BL21(DE3) and determine the best synergistic phaP gene combination to produce polyhydroxybutyrate (PHB). We identified novel phasins from a PHB high-producer strain, Halomonas sp. YLGW01, and introduced a combination of phaP genes into Escherichia coli. The resulting E. coli phaP1,3 strain had enhanced PHB production by 2.9-fold, leading to increased cell mass and increased PHB content from 48 % to 65 %. This strain also showed increased tolerance to inhibitors, such as furfural and vanillin, enabling the utilization of lignocellulose biosugar as a carbon source. These results suggested that the combination of phaP1 and phaP3 genes from H. sp. YLGW01 could increase PHB production and robustness.

Study of SarA by DNA Affinity Capture Assay (DACA) Employing Three Promoters of Key Virulence and Resistance Genes in Methicillin-Resistant Staphylococcus aureus.

Methicillin-resistant Staphylococcus aureus (MRSA), one of the most well-known human pathogens, houses many virulence factors and regulatory proteins that confer resistance to diverse antibiotics. Although they have been investigated intensively, the correlations among virulence factors, regulatory proteins and antibiotic resistance are still elusive. We aimed to identify the most significant global MRSA regulator by concurrently analyzing protein-binding and several promoters under same conditions and at the same time point. DNA affinity capture assay (DACA) was performed with the promoters of mecA, sarA, and sarR, all of which significantly impact survival of MRSA. Here, we show that SarA protein binds to all three promoters. Consistent with the previous reports, ΔsarA mutant exhibited weakened antibiotic resistance to oxacillin and reduced biofilm formation. Additionally, production and activity of many virulence factors such as phenol-soluble modulins (PSM), α-hemolysin, motility, staphyloxanthin, and other related proteins were decreased. Comparing the sequence of SarA with that of clinical strains of various lineages showed that all sequences were highly conserved, in contrast to that observed for AgrA, another major regulator of virulence and resistance in MRSA. We have demonstrated that SarA regulates antibiotic resistance and the expression of various virulence factors. Our results warrant that SarA could be a leading target for developing therapeutic agents against MRSA infections.

Three-dimensional heart extracellular matrix enhances chemically induced direct cardiac reprogramming.

Direct cardiac reprogramming has emerged as a promising therapeutic approach for cardiac regeneration. Full chemical reprogramming with small molecules to generate cardiomyocytes may be more amenable than genetic reprogramming for clinical applications as it avoids safety concerns associated with genetic manipulations. However, challenges remain regarding low conversion efficiency and incomplete cardiomyocyte maturation. Furthermore, the therapeutic potential of chemically induced cardiomyocytes (CiCMs) has not been investigated. Here, we report that a three-dimensional microenvironment reconstituted with decellularized heart extracellular matrix can enhance chemical reprogramming and cardiac maturation of fibroblasts to cardiomyocytes. The resultant CiCMs exhibit elevated cardiac marker expression, sarcomeric organization, and improved electrophysiological features and drug responses. We investigated the therapeutic potential of CiCMs reprogrammed in three-dimensional heart extracellular matrix in a rat model of myocardial infarction. Our platform can facilitate the use of CiCMs for regenerative medicine, disease modeling, and drug screening.

Investigation of metabolic crosstalk between host and pathogenic Clostridioides difficile via multiomics approaches.

Clostridioides difficile is a gram-positive anaerobic bacterium that causes antibiotic-associated infections in the gut. C. difficile infection develops in the intestine of a host with an imbalance of the intestinal microbiota and, in severe cases, can lead to toxic megacolon, intestinal perforation, and even death. Despite its severity and importance, however, the lack of a model to understand host-pathogen interactions and the lack of research results on host cell effects and response mechanisms under C. difficile infection remain limited. Here, we developed an in vitro anaerobic-aerobic C. difficile infection model that enables direct interaction between human gut epithelial cells and C. difficile through the Mimetic Intestinal Host-Microbe Interaction Coculture System. Additionally, an integrative multiomics approach was applied to investigate the biological changes and response mechanisms of host cells caused by C. difficile in the early stage of infection. The C. difficile infection model was validated through the induction of disaggregation of the actin filaments and disruption of the intestinal epithelial barrier as the toxin-mediated phenotypes following infection progression. In addition, an upregulation of stress-induced chaperones and an increase in the ubiquitin proteasomal pathway were identified in response to protein stress that occurred in the early stage of infection, and downregulation of proteins contained in the electron transfer chain and ATP synthase was observed. It has been demonstrated that host cell energy metabolism is inhibited through the glycolysis of Caco-2 cells and the reduction of metabolites belonging to the TCA cycle. Taken together, our C. difficile infection model suggests a new biological response pathway in the host cell induced by C. difficile during the early stage of infection at the molecular level under anaerobic-aerobic conditions. Therefore, this study has the potential to be applied to the development of future therapeutics through basic metabolic studies of C. difficile infection.

Enhanced tolerance of Cupriavidus necator NCIMB 11599 to lignocellulosic derived inhibitors by inserting NAD salvage pathway genes.

Polyhydroxybutyrate (PHB) is a bio-based, biodegradable and biocompatible plastic that has the potential to replace petroleum-based plastics. Lignocellulosic biomass is a promising feedstock for industrial fermentation to produce bioproducts such as polyhydroxybutyrate (PHB). However, the pretreatment processes of lignocellulosic biomass lead to the generation of toxic byproducts, such as furfural, 5-HMF, vanillin, and acetate, which affect microbial growth and productivity. In this study, to reduce furfural toxicity during PHB production from lignocellulosic hydrolysates, we genetically engineered Cupriavidus necator NCIMB 11599, by inserting the nicotine amide salvage pathway genes pncB and nadE to increase the NAD(P)H pool. We found that the expression of pncB was the most effective in improving tolerance to inhibitors, cell growth, PHB production and sugar consumption rate. In addition, the engineered strain harboring pncB showed higher PHB production using lignocellulosic hydrolysates than the wild-type strain. Therefore, the application of NAD salvage pathway genes improves the tolerance of Cupriavidus necator to lignocellulosic-derived inhibitors and should be used to optimize PHB production.

Coproduction of exopolysaccharide and polyhydroxyalkanoates from Sphingobium yanoikuyae BBL01 using biochar pretreated plant biomass hydrolysate.

Sphingobium yanoikuyae BBL01 can produce exopolysaccharides (EPS) and polyhydroxyalkanoates (PHAs). The effect of side products (furfural, hydroxymethylfurfural (HMF), vanillin, and acetate) produced during pretreatment of biomass was evaluated on S. yanoikuyae BBL01. It was observed that a certain concentration range (0.01-0.03 %) of these compounds can improve growth, EPS production, and polyhydroxybutyrate (PHB) accumulation. The addition of HMF increases glucose and xylose utilization while other side products have a negative effect. The C/N of 5 favors EPS production (3.24 ± 0.05 g/L), while a higher C/N ratio of 30 promotes PHB accumulation (38.7 ± 0.08 % w/w), when commercial sugar is used as a carbon source. Pine biomass-derived biochar was able to remove 40 ± 2.1 % of total phenolic. Various biomass hydrolysates were evaluated and the use of detoxified pine biomass hydrolysate (DPH) as a carbon source resulted in the higher coproduction of EPS (2.83 ± 0.03 g/L) and PHB (40.8 ± 2.4 % w/w).

Leucyl-tRNA Synthetase Inhibitor, D-Norvaline, in Combination with Oxacillin, Is Effective against Methicillin-Resistant Staphylococcus aureus.

Methicillin-resistant Staphylococcus aureus (MRSA) is a pathogenic bacterium that causes severe diseases in humans. For decades, MRSA has acquired substantial resistance against conventional antibiotics through regulatory adaptation, thereby posing a challenge for treating MRSA infection. One of the emerging strategies to combat MRSA is the combinatory use of antibacterial agents. Based on the dramatic change in phospholipid fatty acid (PLFA) composition of MRSA in previous results, this study investigated branched-chain amino acid derivatives (precursors of fatty acid synthesis of cell membrane) and discovered the antimicrobial potency of D-norvaline. The compound, which can act synergistically with oxacillin, is among the three leucine-tRNA synthetase inhibitors with high potency to inhibit MRSA cell growth and biofilm formation. PLFA analysis and membrane properties revealed that D-norvaline decreased the overall amount of PLFA, increasing the fluidity and decreasing the hydrophobicity of the bacterial cell membrane. Additionally, we observed genetic differences to explore the response to D-norvaline. Furthermore, deletion mutants and clinically isolated MRSA strains were treated with D-norvaline. The study revealed that D-norvaline, with low concentrations of oxacillin, was effective in killing several MRSA strains. In summary, our findings provide a new combination of aminoacyl-tRNA synthetase inhibitor D-norvaline and oxacillin, which is effective against MRSA.

Thymol Reduces agr-Mediated Virulence Factor Phenol-Soluble Modulin Production in Staphylococcus aureus.

Staphylococcus aureus is a major human bacterial pathogen that carries a large number of virulence factors. Many virulence factors of S. aureus are regulated by the accessory gene regulator (agr) quorum-sensing system. Phenol-soluble modulins (PSMs) are one of the agr-mediated virulence determinants known to play a significant role in S. aureus pathogenesis. In the present study, the efficacy of thymol to inhibit PSM production including δ-toxin in S. aureus was explored. We employed liquid chromatography-mass spectrometry (LC-MS) to quantify the PSMsα1-PSMα4, PSMß1 and PSMß2, and δ-toxin production from culture supernatants. We found that thymol at 0.5 MIC (128 µg/mL) significantly reduced the PSMα and δ-toxin production in S. aureus WKZ-1, WKZ-2, LAC USA300, and ATCC29213. Downregulation in transcription by quantitative real-time (qRT) PCR analysis of response regulator agrA and receptor histidine kinase agrC upon 0.5 MIC thymol treatment affirmed the results of LC-MS quantification of PSMs. In silico molecular docking analysis demonstrated the binding affinity of thymol with receptors AgrA and AgrC. Transmission electron microscopy images revealed no ultrastructural alterations (cell wall and membrane) in thymol-treated WKZ-1 and WKZ-2 S. aureus strains. Here, we demonstrated that thymol reduces various PSM production in S. aureus clinical isolates and reference strains with mass spectrometry.

Tissue extracellular matrix hydrogels as alternatives to Matrigel for culturing gastrointestinal organoids.

Matrigel, a mouse tumor extracellular matrix protein mixture, is an indispensable component of most organoid tissue culture. However, it has limited the utility of organoids for drug development and regenerative medicine due to its tumor-derived origin, batch-to-batch variation, high cost, and safety issues. Here, we demonstrate that gastrointestinal tissue-derived extracellular matrix hydrogels are suitable substitutes for Matrigel in gastrointestinal organoid culture. We found that the development and function of gastric or intestinal organoids grown in tissue extracellular matrix hydrogels are comparable or often superior to those in Matrigel. In addition, gastrointestinal extracellular matrix hydrogels enabled long-term subculture and transplantation of organoids by providing gastrointestinal tissue-mimetic microenvironments. Tissue-specific and age-related extracellular matrix profiles that affect organoid development were also elucidated through proteomic analysis. Together, our results suggest that extracellular matrix hydrogels derived from decellularized gastrointestinal tissues are effective alternatives to the current gold standard, Matrigel, and produce organoids suitable for gastrointestinal disease modeling, drug development, and tissue regeneration.

An Integrative Multiomics Approach to Characterize Prebiotic Inulin Effects on Faecalibacterium prausnitzii.

Faecalibacterium prausnitzii, a major commensal bacterium in the human gut, is well known for its anti-inflammatory effects, which improve host intestinal health. Although several studies have reported that inulin, a well-known prebiotic, increases the abundance of F. prausnitzii in the intestine, the mechanism underlying this effect remains unclear. In this study, we applied liquid chromatography tandem mass spectrometry (LC-MS/MS)-based multiomics approaches to identify biological and enzymatic mechanisms of F. prausnitzii involved in the selective digestion of inulin. First, to determine the preference for dietary carbohydrates, we compared the growth of F. prausnitzii in several carbon sources and observed selective growth in inulin. In addition, an LC-MS/MS-based intracellular proteomic and metabolic profiling was performed to determine the quantitative changes in specific proteins and metabolites of F. prausnitzii when grown on inulin. Interestingly, proteomic analysis revealed that the putative proteins involved in inulin-type fructan utilization by F. prausnitzii, particularly ß-fructosidase and amylosucrase were upregulated in the presence of inulin. To investigate the function of these proteins, we overexpressed bfrA and ams, genes encoding ß-fructosidase and amylosucrase, respectively, in Escherichia coli, and observed their ability to degrade fructan. In addition, the enzyme activity assay demonstrated that intracellular fructan hydrolases degrade the inulin-type fructans taken up by fructan ATP-binding cassette transporters. Furthermore, we showed that the fructose uptake activity of F. prausnitzii was enhanced by the fructose phosphotransferase system transporter when inulin was used as a carbon source. Intracellular metabolomic analysis indicated that F. prausnitzii could use fructose, the product of inulin-type fructan degradation, as an energy source for inulin utilization. Taken together, this study provided molecular insights regarding the metabolism of F. prauznitzii for inulin, which stimulates the growth and activity of the beneficial bacterium in the intestine.

An integrative multiomics approach to characterize anti-adipogenic and anti-lipogenic effects of Akkermansia muciniphila in adipocytes.

The cellular components of Akkermansia muciniphila are considered potential biotherapeutics for the improvement of obesity, diabetes, and metabolic diseases. However, the molecular-based mechanism of A. muciniphila for treatment of obesity, which can provide important evidence for human research, has rarely been explored. Here, we applied integrative multiomics approaches to investigate the underlying molecular mechanism involved in obesity treatment by A. muciniphila. First, the treatment with a cell lysate of A. muciniphila reduced lipid accumulation in 3T3-L1 cells and downregulated the mRNA expression of proteins involved in adipogenesis and lipogenesis. Our proteomic results revealed that A. muciniphila decreased the expression of proteins involved in fat cell differentiation, fatty acid metabolism, and energy metabolism in adipocytes. Moreover, A. muciniphila significantly reduced the level of metabolites related to glycolysis, the TCA cycle, and ATP in adipocytes. Interestingly, serine protease inhibitor A3 (SERPINA3) homologs were overexpressed in the 3T3-L1 cells treated with A. muciniphila. Small interfering RNA (siRNA) transfection demonstrated that A. muciniphila upregulates SERPINA3G expression and inhibits lipogenesis in adipocytes. Taken together, our multiomics-based approaches enabled to uncover the molecular mechanism of A. muciniphila for treatment of obesity and provide potent anti-lipogenic agents.

Novel Polyhydroxybutyrate-Degrading Activity of the Microbulbifer Genus as Confirmed by Microbulbifer sp. SOL03 from the Marine Environment.

Ever since bioplastics were globally introduced to a wide range of industries, the disposal of used products made with bioplastics has become an issue inseparable from their application. Unlike petroleum-based plastics, bioplastics can be completely decomposed into water and carbon dioxide by microorganisms in a relatively short time, which is an advantage. However, there is little information on the specific degraders and accelerating factors for biodegradation. To elucidate a new strain for biodegrading poly-3-hydroxybutyrate (PHB), we screened out one PHB-degrading bacterium, Microbulbifer sp. SOL03, which is the first reported strain from the Microbulbifer genus to show PHB degradation activity, although Microbulbifer species are known to be complex carbohydrate degraders found in high-salt environments. In this study, we evaluated its biodegradability using solid- and liquid-based methods in addition to examining the changes in physical properties throughout the biodegradation process. Furthermore, we established the optimal conditions for biodegradation with respect to temperature, salt concentration, and additional carbon and nitrogen sources; accordingly, a temperature of 37°C with the addition of 3% NaCl without additional carbon sources, was determined to be optimal. In summary, we found that Microbulbifer sp. SOL03 showed a PHB degradation yield of almost 97% after 10 days. To the best of our knowledge, this is the first study to investigate the potent bioplastic degradation activity of Microbulbifer sp., and we believe that it can contribute to the development of bioplastics from application to disposal.

Novel phasins from the Arctic Pseudomonas sp. B14-6 enhance the production of polyhydroxybutyrate and increase inhibitor tolerance.

Phasin (PhaP), one of the polyhydroxyalkanoate granule-associated protein, enhances cell growth and polyhydroxybutyrate (PHB) biosynthesis by regulating the number and size of PHB granules. However, few studies have applied phasins to various PHB production conditions. In this study, we identified novel phasin genes from the genomic data of Arctic soil bacterium Pseudomonas sp. B14-6 and determined the role of phaP1Ps under different PHB production conditions. Transmission electron microscopy and gel permeation chromatography revealed small PHB granules with high-molecular weight, while differential scanning calorimetry showed that the extracted PHB films had similar thermal properties. The phasin protein derived from Pseudomonas sp. B14-6 revealed higher PHB production and exhibited higher tolerance to several lignocellulosic biosugar-based inhibitors than the phasin protein of Ralstonia eutropha H16 in a recombinant Escherichia coli strain. The increased tolerance to propionate, temperature, and other inhibitors was attributed to the introduction of phaP1Ps, which increased PHB production from lignocellulosic hydrolysate (2.39-fold) in the phaP1Ps strain. However, a combination of phasin proteins isolated from two different sources did not increase PHB production. These findings suggest that phasin could serve as a powerful means to increase robustness and PHB production in heterologous strains.

Microfluidic device with brain extracellular matrix promotes structural and functional maturation of human brain organoids.

Brain organoids derived from human pluripotent stem cells provide a highly valuable in vitro model to recapitulate human brain development and neurological diseases. However, the current systems for brain organoid culture require further improvement for the reliable production of high-quality organoids. Here, we demonstrate two engineering elements to improve human brain organoid culture, (1) a human brain extracellular matrix to provide brain-specific cues and (2) a microfluidic device with periodic flow to improve the survival and reduce the variability of organoids. A three-dimensional culture modified with brain extracellular matrix significantly enhanced neurogenesis in developing brain organoids from human induced pluripotent stem cells. Cortical layer development, volumetric augmentation, and electrophysiological function of human brain organoids were further improved in a reproducible manner by dynamic culture in microfluidic chamber devices. Our engineering concept of reconstituting brain-mimetic microenvironments facilitates the development of a reliable culture platform for brain organoids, enabling effective modeling and drug development for human brain diseases.