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The Gfo/Idh/MocA family enzyme DgpA was known to catalyze the regiospecific oxidation of puerarin to 3"-oxo-puerarin in the presence of 3-oxo-glucose. Here, we discovered that D3dgpA, dgpA cloned from the human gut bacterium Dorea sp. MRG-IFC3, catalyzed the regiospecific oxidation of various C-/O-glycosides, including puerarin, in the presence of methyl ß-D-3-oxo-glucopyranoside. While C-glycosides were converted to 3"- and 2"-oxo-products by D3dgpA, O-glycosides resulted in the formation of aglycones and hexose enediolone from the 3"-oxo-products. From DFT calculations, it was found that isomerization of 3"-oxo-puerarin to 2"-oxo-puerarin required a small activation energy of 9.86 kcal/mol, and the O-glycosidic bond cleavage of 3"-oxo-products was also thermodynamically favored with a small activation energy of 3.49 kcal/mol. In addition, the reaction mechanism of D3dgpA was discussed in comparison to those of Gfo/Idh/MocA and GMC family enzymes. The robust reactivity of D3dgpA was proposed as a new general route for derivatization of glycosides.
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Defect engineering of metal-organic frameworks (MOFs) is a promising strategy for tailoring the interfacial characteristics between MOFs and polymers, aiming to create high-performance mixed matrix membranes (MMMs). This study introduces a new approach using dual defective alkylamine (AA)-modulated zeolitic imidazolate framework-8 (DAZIF-8), to develop high-flux MMMs. Tributylamine (TBA) and triethylamine (TEA) monodentate ligands coordinate with zinc ions in varying compositions. A mixture of Zn(CH3COO)2·2H2O:2-methylimidazole (Mim):AA in a 1:1.75:5 molar ratio facilitates high-yield coordination between Zn and multiple organic ligands, including Zn-Mim, Zn-TEA, and Zn-TBA (>80%). Remarkably, DAZIF-8 containing 3 mol% TBA and 2 mol% TEA exhibits exceptional characteristics, such as a Brunauer-Emmett-Teller surface area of 1745 m2 g-1 and enhanced framework rigidity. Furthermore, dual Zn-AA coordination sites on the framework's outer surface enhance compatibility with the polyimide (PI) matrix through electron donor-acceptor interactions, enabling the fabrication of high-loading MMMs with excellent mechanical durability. Importantly, the PI/DAZIF-8 (60/40 w/w) MMM demonstrates an unprecedented 759% enhancement in ethylene (C2H4) permeability (281 Barrer) with a moderate ethylene/ethane (C2H4/C2H6) selectivity of 2.95 compared to the PI, surpassing the polymeric upper limit for C2H4/C2H6 separation.
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Human gut bacterium Dorea sp. MRG-IFC3 is unique in that it is capable of metabolizing puerarin, an isoflavone C-glycoside, whereas it shows broad substrate glycosidase activity for the various flavonoid O-glycosides. To address the question on the substrate specificity, as well as biochemical characteristics, cell-free biotransformation of flavonoid glycosides was performed under various conditions. The results showed that there are two different enzyme systems responsible for the metabolism of flavonoid C-glycosides and O-glycosides in the MRG-IFC3 strain. The system responsible for the conversion of puerarin was inducible and comprised of two enzymes. One enzyme oxidizes puerarin to 3"-oxo-puerarin and the other enzyme converts 3"-oxo-puearin to daidzein. The second enzyme was only active toward 3"-oxo-puerarin. The activity of puerarin conversion to daidzein was enhanced in the presence of Mn2+ and NAD+. It was concluded that the puerarin C-deglycosylation by Dorea sp. MRG-IFC3 possibly adopts the same biochemical mechanism as the strain PUE, a species of Dorea longicatena.
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Biotransformação , Flavonoides , Glicosídeos , Isoflavonas , Isoflavonas/metabolismo , Humanos , Flavonoides/metabolismo , Flavonoides/química , Glicosídeos/metabolismo , Especificidade por Substrato , Microbioma GastrointestinalRESUMO
Stathmins are small, unstructured proteins that bind tubulin dimers and are implicated in several human diseases, but whose function remains unknown. We characterized a new stathmin, STMND1 (Stathmin Domain Containing 1) as the human representative of an ancient subfamily. STMND1 features a N-terminal myristoylated and palmitoylated motif which directs it to membranes and a tubulin-binding stathmin-like domain (SLD) that contains an internal nuclear localization signal. Biochemistry and proximity labeling showed that STMND1 binds tubulin, and live imaging showed that tubulin binding inhibits translocation from cellular membranes to the nucleus. STMND1 is highly expressed in multiciliated epithelial cells, where it localizes to motile cilia. Overexpression in a model system increased the length of primary cilia. Our study suggests that the most ancient stathmins have cilium-related functions that involve sensing soluble tubulin.
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Núcleo Celular , Cílios , Estatmina , Tubulina (Proteína) , Cílios/metabolismo , Tubulina (Proteína)/metabolismo , Humanos , Estatmina/metabolismo , Núcleo Celular/metabolismo , Filogenia , Ligação Proteica , Sinais de Localização Nuclear/metabolismo , Animais , Células Epiteliais/metabolismo , Transporte Proteico , Sequência de AminoácidosRESUMO
BACKGROUND: Antibody-drug conjugates (ADCs) enhance the specificity of cytotoxic drugs by directing them to cells expressing target antigens. Multiple ADCs are FDA-approved for solid and hematologic malignancies, including those expressing HER2, TROP2, and NECTIN4. Recently, an ADC targeting HER2 (Trastuzumab-Deruxtecan) increased survival and reduced growth of brain metastases in treatment-refractory metastatic breast cancer, even in tumors with low HER2 expression. Thus, low-level expression of ADC targets may be sufficient for treatment responsiveness. However, ADC target expression is poorly characterized in many central nervous system (CNS) tumors. METHODS: We analyzed publicly available RNA-sequencing and proteomic data from the children's brain tumor network (Nâ =â 188 tumors) and gene-expression-omnibus RNA-expression datasets (Nâ =â 356) to evaluate expression of 14 potential ADC targets that are FDA-approved or under investigation in solid cancers. We also used immunohistochemistry to measure the levels of HER2, HER3, NECTIN4, TROP2, CLDN6, CLDN18.2, and CD276/B7-H3 protein in glioblastoma, oligodendroglioma, meningioma, ependymoma, pilocytic astrocytoma, medulloblastoma, atypical teratoid/rhabdoid tumor (AT/RT), adamantinomatous craniopharyngioma (ACP), papillary craniopharyngioma (PCP), and primary CNS lymphoma (Nâ =â 575). RESULTS: Pan-CNS analysis showed subtype-specific expression of ADC target proteins. Most tumors expressed HER3, B7-H3, and NECTIN4. Ependymomas strongly expressed HER2, while meningiomas showed weak-moderate HER2 expression. ACP and PCP strongly expressed B7-H3, with TROP2 expression in whorled ACP epithelium. AT/RT strongly expressed CLDN6. Glioblastoma showed little subtype-specific marker expression, suggesting a need for further target development. CONCLUSIONS: CNS tumors exhibit subtype-specific expression of ADC targets including several FDA-approved for other indications. Clinical trials of ADCs in CNS tumors may therefore be warranted.
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Neoplasias da Mama , Neoplasias do Sistema Nervoso Central , Neoplasias Cerebelares , Glioblastoma , Imunoconjugados , Tumor Rabdoide , Criança , Humanos , Feminino , Glioblastoma/tratamento farmacológico , Proteômica , Imunoconjugados/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Neoplasias do Sistema Nervoso Central/tratamento farmacológico , Tumor Rabdoide/tratamento farmacológico , Neoplasias Cerebelares/tratamento farmacológico , RNA/uso terapêutico , Claudinas/uso terapêutico , Antígenos B7RESUMO
In this study, three nitrogen-containing aluminum-based metal-organic frameworks (Al-MOFs), namely, CAU-10pydc, MOF-303, and KMF-1, were investigated for the efficient separation of a C2H2/CO2 gas mixture. Among these three Al-MOFs, KMF-1 demonstrated the highest selectivity for C2H2/CO2 separation (6.31), primarily owing to its superior C2H2 uptake (7.90 mmol g-1) and lower CO2 uptake (2.82 mmol g-1) compared to that of the other two Al-MOFs. Dynamic breakthrough experiments, using an equimolar binary C2H2/CO2 gas mixture, demonstrated that KMF-1 achieved the highest separation performance. It yielded 3.42 mmol g-1 of high-purity C2H2 (>99.95%) through a straightforward desorption process under He purging at 298 K and 1 bar. To gain insights into the distinctive characteristics of the pore surfaces of structurally similar CAU-10pydc and KMF-1, we conducted computational simulations using canonical Monte Carlo and dispersion-corrected density functional theory methods. These simulations revealed that the secondary amine (C2N-H) groups in KMF-1 played a more significant role in differentiating between C2H2 and CO2 compared to that of the N atoms in CAU-10pydc and MOF-303. Consequently, KMF-1 emerged as a promising adsorbent for the separation of high-purity C2H2 from binary C2H2/CO2 gas mixtures.
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The typical Korean diet contains a significant quantity of doenjang owing to its unique taste and health benefits. However, the presence of anti-nutritional and toxic substances, such as biogenic amines and microbial pathogens, in doenjang has resulted in a loss of revenue and poor consumer health. The present study focused on the identification and quantification of different biogenic amines, pathogenic Bacillus cereus, and yeast counts in 36 doenjang products (designated as De-1 to De-36, 500 g each) procured from the different cottage industries situated in different parts of the Republic of Korea. The results indicated, only three samples were contaminated with B. cereus, exceeding the recommended limit (4 log CFU/g) suggested by the national standards of Korea. A total of six distinct yeasts were identified in different doenjang samples, whose comprehensive enzymatic profiling suggested the absence of harmful enzymes such as N-acetyl-ß-glucosaminidase, α-chymotrypsin, and ß-glucuronidase. The biogenic amines were detected in the range of 67.68 mg/kg to 2556.68 mg/kg and classified into six major groups based on hierarchical cluster analysis. All doenjang samples contained tryptamine, putrescine, cadaverine, histamine, and tyramine, while 94.44% were positive for spermidine and spermine. The results documented the analysis of traditional cottage industry doenjang and suggest the need for constant monitoring to ensure the safety of food for the consumer.
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Nuclear atypia, including altered nuclear size, contour, and chromatin organization, is ubiquitous in cancer cells. Atypical primary nuclei and micronuclei can rupture during interphase; however, the frequency, causes, and consequences of nuclear rupture are unknown in most cancers. We demonstrate that nuclear envelope rupture is surprisingly common in many human cancers, particularly glioblastoma. Using highly-multiplexed 2D and super-resolution 3D-imaging of glioblastoma tissues and patient-derived xenografts and cells, we link primary nuclear rupture with reduced lamin A/C and micronuclear rupture with reduced lamin B1. Moreover, ruptured glioblastoma cells activate cGAS-STING-signaling involved in innate immunity. We observe that local patterning of cell states influences tumor spatial organization and is linked to both lamin expression and rupture frequency, with neural-progenitor-cell-like states exhibiting the lowest lamin A/C levels and greatest susceptibility to primary nuclear rupture. Our study reveals that nuclear instability is a core feature of cancer, and links nuclear integrity, cell state, and immune signaling.
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Water and other small molecules frequently coordinate within metal-organic frameworks (MOFs). These coordinated molecules may actively engage in mass transfer, moving together with the transport molecules, but this phenomenon has yet to be examined. In this study, we explore a unique water transfer mechanism in UTSA-280, where an incoming water molecule can displace a coordinated molecule for mass transfer. We refer to this process as the "knock-off" mechanism. Despite UTSA-280 possessing one-dimensional channels, the knock-off transport enables water movement along the other two axes, effectively simulating a pseudo-three-dimensional mass transfer. Even with a relatively narrow pore width, the knock-off mechanism enables a high water flux in the UTSA-280 membrane. The knock-off mechanism also renders UTSA-280 superior water/ethanol diffusion selectivity for pervaporation. To validate this unique mechanism, we conducted 1 H and 2 H solid-state NMR on UTSA-280 after the adsorption of deuterated water. We also derived potential energy diagrams from the density functional theory to gain atomic-level insight into the knock-off and the direct-hopping mechanisms. The simulation findings reveal that the energy barrier of the knock-off mechanism is marginally lower than the direct-hopping pathway, implying its potential role in enhancing water diffusion in UTSA-280.
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PURPOSE: To describe the optical coherence tomography features of pachyvitelliform maculopathy (PVM), an acquired vitelliform lesion (AVL) associated with pachychoroid disease. METHODS: This study was a retrospective, multicentre, observational analysis.Medical records and multimodal imaging were reviewed in all patients with pachychoroid disease and AVL. Visual acuity, central choroidal thickness (CCT), AVL dimensions, total choroidal area, luminal choroidal area, stromal choroidal area and choroidal vascular index were measured in all eyes with PVM and compared with normal age-matched control eyes. RESULTS: Mean age of the PVM group (17 eyes of 17 patients) was 71.41 years. Average follow-up was 33.15 months. Baseline VA was 20/40 in the PVM group and declined to 20/100 (p=0.006). AVLs were all detected overlying pachyvessels with optical coherence tomography and were all hyperautofluorescent with fundus autofluorescent imaging. Mean CCT in the PVM group was significantly greater (352.35 µm) than the CCT in the control group (226.88 µm, p<0.001). Retinal pigment epithelium (RPE) disruption was present in 64.71% of eyes with PVM at baseline and 41.18% developed macular atrophy at the end of follow-up. CONCLUSIONS: PVM, defined by the presence of AVL associated with pachychoroid features, is a distinct novel entity of the pachychoroid disease spectrum. This study suggests a possible pathogenesis of RPE dysfunction secondary to a thick choroid, leading to accumulation of undigested photoreceptor outer segments and AVL. Clinicians should be aware of this common cause of vitelliform lesions and the poor visual prognosis due to the high risk of atrophy development.
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Structural flexibility is a critical issue that limits the application of metal-organic framework (MOF) membranes for gas separation. Herein we propose a mixed-linker approach to suppress the structural flexibility of the CAU-10-based (CAU = Christian-Albrechts-University) membranes. Specifically, pure CAU-10-PDC membranes display high separation performance but at the same time are highly unstable for the separation of CO2/CH4. A partial substitution (30 mol.%) of the linker PDC with BDC significantly improves its stability. Such an approach also allows for decreasing the aperture size of MOFs. The optimized CAU-10-PDC-H (70/30) membrane possesses a high separation performance for CO2/CH4 (separation factor of 74.2 and CO2 permeability of 1,111.1 Barrer under 2 bar of feed pressure at 35°C). A combination of in situ characterization with X-ray diffraction (XRD) and diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, as well as periodic density functional theory (DFT) calculations, unveils the origin of the mixed-linker approach to enhancing the structural stability of the mixed-linker CAU-10-based membranes during the gas permeation tests.
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BACKGROUND: Evaluate the visual outcomes of Ahmed glaucoma valve implantation (AGVI) in patients with neovascular glaucoma (NVG) who underwent diabetic vitrectomy and suggest appropriate AGVI timing. METHODS: Medical records of patients who underwent AGVI due to NVG after diabetic vitrectomy were reviewed. Successful intraocular pressure (IOP) control was defined as an IOP between 6 and 21 mmHg. Visual outcome was compared before NVG diagnosis and after AGVI, and the "favorable" visual outcome was defined as a postoperative deterioration in BCVA of less than 0.3 logMAR units compared to those before the development of NVG. Various factors including surgical timing were evaluated to identify the risk factors associated with unfavorable visual outcome. RESULTS: A total of 35 eyes were enrolled and divided into group 1(medically uncontrolled NVG group, IOP more than 30mmHg, 16 eyes) and group 2(NVG group responded well to the initial non-surgical treatment but eventually required AGVI, 19 eyes). Despite the favorable rate of normalization of post-AGVI IOP (85.7%), 43.8% in Group 1 and 26.3% in Group 2 showed unfavorable visual outcomes. In group 1, delayed surgical timing more than 1 week from the NVG diagnosis showed a significant association with unfavorable visual outcomes (P = 0.041). In group 2, poor patient compliance (follow up loss, refuse surgery) was the main factor of unfavorable visual outcomes. CONCLUSION: When NVG occurs in patients with proliferative diabetic retinopathy after vitrectomy, physicians should be cautious not to delay the surgical intervention, especially in patients with IOP of 30 or more despite non-surgical treatment. Early AGVI within six days might be necessary to preserve useful vision in these patients.
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Diabetes Mellitus , Retinopatia Diabética , Implantes para Drenagem de Glaucoma , Glaucoma Neovascular , Glaucoma , Humanos , Glaucoma Neovascular/diagnóstico , Glaucoma Neovascular/etiologia , Glaucoma Neovascular/cirurgia , Vitrectomia , Glaucoma/cirurgia , Retinopatia Diabética/diagnóstico , Retinopatia Diabética/cirurgia , Retinopatia Diabética/complicações , Pressão Intraocular , Prognóstico , Estudos RetrospectivosRESUMO
Aflatoxins are the mycotoxins that contaminate food and feed and pose health hazards to humans and animals. Here, Bacillus albusYUN5 was isolated from doenjang (Korean fermented soybean paste) and examined for aflatoxin B1 (AFB1) and aflatoxin G1 (AFG1) degradation capabilities. The highest degradation of AFB1 (76.28 ± 0.15%) and AFG1 (98.98 ± 0.00%) was observed in the cell-free supernatant (CFS) ofB. albusYUN5, whereas negligible degradation was observed in intracellular fraction, viable cells, and cell debris. Furthermore, heat (100 °C) and proteinase K treated CFS possessed AFB1 and AFG1 degradation ability, suggesting that substances other than proteins or enzymes are responsible for the degradation. Optimal degradation of AFB1 and AFG1 by the CFS was achieved at 55 °C and 45 °C, respectively, and at pH 7-10 and salt concentration of 0-20%. Liquid chromatography-mass spectroscopy analysis of the degraded products revealed that either the difuran or lactone ring of AFB1 and lactone ring of AFG1 is the main target site by CFS of B. albus YUN5. A slightly better reduction of AFB1 and AFG1 was observed in doenjang treated with CFS and viable cells of B. albus YUN5 compared to those without CFS and B. albus YUN5 treated doenjang during one year of fermentation, suggesting the applicability of B. albus in real food.
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Aflatoxinas , Bacillus , Animais , Humanos , Aflatoxina B1 , Lactonas , República da CoreiaRESUMO
Metal-organic frameworks (MOFs) are promising candidates for membrane gas separation. MOF-based membranes include pure MOF membranes and MOF-based mixed matrix membranes (MMMs). This Perspective discusses the challenges for the next stage of the development of MOF-based membranes based on research conducted in the past decade. We focused on three major issues associated with pure MOF membranes. First, some MOF compounds have been overstudied, despite the availability of numerous MOFs. Second, gas adsorption and diffusion in MOFs are often independently investigated. The correlation between adsorption and diffusion has seldom been discussed. Third, we identify the importance of characterizing the gas distribution in MOFs to understand the structure-property relationships for gas adsorption and diffusion in MOF membranes. For MOF-based MMMs, engineering the MOF-polymer interface is essential for achieving the desired separation performance. Various approaches to modify the MOF surface or polymer molecular structure have been proposed to improve the MOF-polymer interface. Herein, we present defect engineering as a facile and efficient approach for engineering the MOF-polymer interfacial morphology and its extended application for various gas separations.
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Gochujang (fermented hot pepper paste) products are well known for their distinct, spicy flavor. However, frequent pack burst spoilage of gochujang products occurs during transportation and storage because of microbial aerogenesis, resulting in considerable economic losses. The present study aimed to prevent pack burst spoilage of gochujang products by supplementing them with garlic ethanol extract. A simulated pack burst experiment revealed that 42.86 % of normal gochujang products were spoiled. Garlic ethanol extract significantly inhibited the growth of Zygosaccharomyces rouxii in gochujang products, with low minimum inhibitory concentration values (12.5-25 mg/mL). Gochujang products supplemented with various concentrations (1 % and 2.5 %) of garlic ethanol extract exhibited marked inhibition of microbial growth, particularly Z. rouxii, and pack burst spoilage. Microbiome analysis revealed that the pack burst samples harbored a high abundance of Z. rouxii. Supplementation of gochujang with 1 % garlic ethanol extract drastically reduced Z. rouxii abundance and prevented pack burst. Moreover, gochujang products supplemented with 1 % garlic ethanol extract exhibited a high hedonic score in the sensory analysis. Based on the results of this study, we concluded that supplementation of gochujang products with 1 % garlic ethanol extract before packaging could be effective in preventing pack burst spoilage of gochujang.
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Capsicum , Alho , Etanol , Antioxidantes , Suplementos Nutricionais , Extratos VegetaisRESUMO
Soybean (SB) leaves (SLs) contain diverse flavonoids with health-promoting properties. To investigate the chemical constituents of SB and their correlations across phenotypes, growing periods, and environmental factors, a validated separation method for mass detection was used with targeted metabolomics. Thirty-six polyphenols (1 coumestrol, 5 flavones, 18 flavonols, and 12 isoflavones) were identified in SLs, 31 of which were quantified. Machine learning (ML) modelling was used to differentiate between the variety, bean color, growing period, and cultivation area and identify the key compounds responsible for these differences. The isoflavone and flavonol profiles were influenced by the growing period and cultivation area based on bootstrap forest modelling. The neural model showed the best predictive capacity for SL differences among the various ML models. Discriminant polyphenols can differ depending on the ML method applied; therefore, a cautious approach should be ensured when using statistical ML outputs, including orthogonal partial least squares discriminant analysis.
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Fabaceae , Isoflavonas , Polifenóis/análise , Glycine max , Metabolômica/métodos , Folhas de Planta/química , Aprendizado de Máquina , Flavonóis , FenótipoRESUMO
Previously, we reported that Sargassum horneri (Turner) C. Agardh (S. horneri) is a brown algae species that exerts anti-inflammatory activity toward murine macrophages. However, the anti-neuroinflammatory effects and the mechanism of S. horneri on microglia cells are still unknown. We investigated the anti-neuroinflammatory effects of S. horneri extract on microglia in vitro and in vivo. In the present study, we found that S. horneri was not cytotoxic to BV-2 microglia cells and it significantly decreased lipopolysaccharide (LPS)-induced NO production. Moreover, S. horneri also diminished the protein expression of iNOS, COX-2, and cytokine production, including IL-1ß, TNF-α, and IL-6, on LPS-stimulated microglia activation. S. horneri elicited anti-neuroinflammatory effects by inhibiting phosphorylation of p38 MAPK and NF-κB. In addition, S. horneri inhibited astrocytes and microglia activation in LPS-challenged mice brain. Therefore, these results suggested that S. horneri exerted anti-neuroinflammatory effects on LPS-stimulated microglia cell activation by inhibiting neuroinflammatory factors and NF-κB signaling.
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Congenital hyperinsulinism (CHI) is a rare genetic condition characterized by uncontrolled insulin secretion, resulting in hypoglycemia. Although glucagon has lately been regarded as a therapeutic option for CHI, its use is severely hampered by its poor solubility and stability at physiological pH, as well as its short duration of action. To address these constraints, we developed HM15136, a novel long-acting glucagon analog composed of a glucagon analog conjugated to the Fc fragment of human immunoglobulin G4 via a polyethylene glycol linker. In this study, we established that HM15136 was more soluble than natural glucagon (≥ 150 mg/mL vs 0.03 mg/mL). Next, we confirmed that HM15136 activated glucagon receptor in vitro and induced glycogenolysis and gluconeogenesis in rat primary hepatocytes. Pharmacokinetics (PK)/Pharmacodynamics (PD) analysis of HM15136 shows that HM15136 has a markedly longer half-life (36 h vs. < 5 min) and increased bioavailability (90%) compared to native glucagon in mice. Further, HM15136 could effectively reverse acute hypoglycemia induced by insulin challenge, and multiple doses of HM15136 could sustain increased blood glucose levels in CHI rats. In conclusion, our findings indicate that HM15136 promotes sustained elevation of blood glucose, demonstrating the potential for development as a once-weekly therapy for CHI.
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Hiperinsulinismo Congênito , Hiperinsulinismo , Animais , Humanos , Camundongos , Ratos , Glicemia/análise , Hiperinsulinismo Congênito/tratamento farmacológico , Glucagon , Meia-Vida , Hiperinsulinismo/tratamento farmacológico , Fragmentos Fc das Imunoglobulinas , Insulina/farmacologia , Polietilenoglicóis/farmacologia , Receptores de Glucagon , RoedoresRESUMO
Herein, a new approach for the in situ synthesis of zeolitic imidazolate framework (ZIF) nanoparticles with triple ligands, referred to as Sogang ZIF-8 (SZIF-8), is reported for enhanced C2 H4 /C2 H6 kinetic separation. SZIF-8 consists of tetrahedral zinc metals coordinated with tri-butyl amine (TBA), 2,4-dimethylimidazole (DIm), and 2-methylimidazole (MIm). SZIF-8(x) with different DIm contents in x (up to 23.2 mol%) are synthesized in situ because TBA preferably deprotonates DIm ligands due to the much lower pKa of DIm over MIm, allowing for the Zn-DIm coordination. The Zn-DIm coordination reduces the window size of ZIF-8 with suppressed linker flipping motion due to bulky DIm ligands and simultaneously enhances the interfacial interaction between 6FDA-DAM polyimide (6FDA) and SZIF-8 via electron donor-acceptor interactions. Consequently, 6FDA/SZIF-8(13) mixed matrix membrane exhibits an excellent C2 H4 permeability of 60.3 Barrer and C2 H4 /C2 H6 selectivity of 4.5. The temperature-dependent transport characterization reveals that such excellent C2 H4 /C2 H6 kinetic separation is attained by the enhancement in size discrimination-based energetic selectivity. Our hybrid multi-ligand approach can offer a useful tool for the fine-tuning of molecular structures and textural properties of other metal organic frameworks.
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Consumption of fermented Prunus mume fruit (maesil) sugar syrup raise a health concern due to the presence of the cyanogenic glucoside amygdalin. The goal of the present study was to investigate the amygdalin degradation potential and genome profile of the native microbes found in maesil syrup. The microbial profile analysis revealed that yeast is the predominant microorganism native to maesil syrup and that the isolated yeast cells showed a remarkable potential for amygdalin reduction (99.7%). Moreover, the reduction in amygdalin was inversely proportional to the growth of the isolated yeast. The whole-genome analysis revealed that the isolated yeast is Zygosaccharomyces rouxii (genome size 10 Mb, 39.25% of GC content). Of the 5250 genes (64.88%) predicted in the Z. rouxii genome, 5245 (99.90%) were annotated using NCBI Non-Redundant, UniProt, and InterProScan databases. The genome of the isolated Z. ruoxii harbored 2.03% of repeats and 0.68% of non-coding RNAs. Protein prediction indicated that ß-glycosidases and hydroxynitrile lyase may play a key role in amygdalin degradation. The predicted degradation initiated by ß-glycosidases that hydrolyze α-glucosidic bonds of amygdalin results in α-hydroxy nitriles (cyanohydrins) that are subsequently converted into carbonyl compounds (benzaldehyde) and hydrogen cyanide catalyzed by hydroxynitrile lyases. Present findings provide valuable data for constructing engineered microorganisms that can degrade amygdalin. Further analysis of Z. rouxii may elucidate the exact mechanism of amygdalin reduction in the production of maesil syrup.