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1.
Brain Tumor Pathol ; 2024 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-38597999

RESUMO

Surgical biopsy is the gold standard for diagnosing central nervous system (CNS) lymphomas. However, reliable liquid biopsy methods for diagnosing CNS lymphomas have quickly developed and have been implicated in clinical decision-making. In the current report, we introduce two patients for whom liquid biopsy was essential for diagnosing CNS lymphomas and discuss the rapidly growing applications of this technology.

2.
Curr Opin Biotechnol ; 87: 103133, 2024 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-38640846

RESUMO

Microbial fermentation employs two strategies: growth- and nongrowth-coupled productions. Stoichiometric metabolic models with flux balance analysis enable pathway engineering to couple target synthesis with growth, yielding numerous successful results. Growth-coupled engineering also contributes to improving bottleneck flux through subsequent adaptive evolution. However, because growth-coupled production inevitably shares resources between biomass and target syntheses, the cost-effective production of bulk chemicals mandates a nongrowth-coupled approach. In such processes, understanding how and when to transition the metabolic state from growth to production modes becomes crucial, as does maintaining cellular activity during the nongrowing state to achieve high productivity. In this paper, we review recent technologies for growth-coupled and nongrowth-coupled production, considering their advantages and disadvantages.

3.
Acta Neuropathol ; 147(1): 76, 2024 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-38658413

RESUMO

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune disease of the CNS characterized by the production of disease-specific autoantibodies against aquaporin-4 (AQP4) water channels. Animal model studies suggest that anti-AQP4 antibodies cause a loss of AQP4-expressing astrocytes, primarily via complement-dependent cytotoxicity. Nonetheless, several aspects of the disease remain unclear, including: how anti-AQP4 antibodies cross the blood-brain barrier from the periphery to the CNS; how NMOSD expands into longitudinally extensive transverse myelitis or optic neuritis; how multiphasic courses occur; and how to prevent attacks without depleting circulating anti-AQP4 antibodies, especially when employing B-cell-depleting therapies. To address these knowledge gaps, we conducted a comprehensive 'stage-dependent' investigation of immune cell elements in situ in human NMOSD lesions, based on neuropathological techniques for autopsied/biopsied CNS materials. The present study provided three major findings. First, activated or netting neutrophils and melanoma cell adhesion molecule-positive (MCAM+) helper T (TH) 17/cytotoxic T (TC) 17 cells are prominent, and the numbers of these correlate with the size of NMOSD lesions in the initial or early-active stages. Second, forkhead box P3-positive (FOXP3+) regulatory T (Treg) cells are recruited to NMOSD lesions during the initial, early-active or late-active stages, suggesting rapid suppression of proinflammatory autoimmune events in the active stages of NMOSD. Third, compartmentalized resident memory immune cells, including CD103+ tissue-resident memory T (TRM) cells with long-lasting inflammatory potential, are detected under "standby" conditions in all stages. Furthermore, CD103+ TRM cells express high levels of granzyme B/perforin-1 in the initial or early-active stages of NMOSD in situ. We infer that stage-dependent compartmentalized immune traits orchestrate the pathology of anti-AQP4 antibody-guided NMOSD in situ. Our work further suggests that targeting activated/netting neutrophils, MCAM+ TH17/TC17 cells, and CD103+ TRM cells, as well as promoting the expansion of FOXP3+ Treg cells, may be effective in treating and preventing relapses of NMOSD.


Assuntos
Aquaporina 4 , Autoanticorpos , Neuromielite Óptica , Neutrófilos , Neuromielite Óptica/imunologia , Neuromielite Óptica/patologia , Aquaporina 4/imunologia , Humanos , Neutrófilos/imunologia , Neutrófilos/patologia , Feminino , Autoanticorpos/imunologia , Masculino , Pessoa de Meia-Idade , Memória Imunológica , Adulto , Idoso , Células Th17/imunologia , Células Th17/patologia
4.
Neuropathology ; 2024 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-38583489

RESUMO

An 84-year-old man presented with somnolence, dysphagia, and right hemiplegia, all occurring within a month, approximately one year after initial admission due to subacute, transient cognitive decline suggestive of acute disseminated encephalomyelitis involving the cerebral white matter. Serial magnetic resonance imaging (MRI) studies over that period revealed three high-intensity signal lesions on fluid-attenuated inversion recovery images, appearing in chronological order in the left upper and left lower medulla oblongata and left pontine base. Despite some clinical improvement following methylprednisolone pulse therapy, the patient died of respiratory failure. Autopsy revealed four fresh, well-defined lesions in the brainstem, three of which corresponded to the lesions detected radiologically. The remaining lesion was located in the dorsal medulla oblongata and involved the right solitary nucleus. This might have appeared at a later disease stage, eventually causing respiratory failure. Histologically, all four lesions showed loss of myelin, preservation of axons, and infiltration of lymphocytes, predominantly CD8-positive T cells, consistent with the histological features of autoimmune demyelinating diseases, particularly the confluent demyelination observed in the early and acute phases of multiple sclerosis (MS). In the cerebral white matter, autoimmune demyelination appeared superimposed on ischemic changes, consistent with the cerebrospinal fluid (CSF) and MRI findings on initial admission. No anti-AQP4 or MOG antibodies or those potentially causing autoimmune encephalitis/demyelination were detected in either the serum or CSF. Despite several similarities to MS, such as the relapsing-remitting disease course and lesion histology, the entire clinicopathological picture in the present patient, especially the advanced age at onset and development of brainstem lesions in close proximity within a short time frame, did not fit those of MS or other autoimmune diseases that are currently established. The present results suggest that exceptionally older individuals can be affected by an as yet unknown inflammatory demyelinating disease of the CNS.

5.
J Biosci Bioeng ; 137(3): 187-194, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38281859

RESUMO

Overexpression of proteins by introducing a DNA vector is among the most important tools for the metabolic engineering of microorganisms such as Escherichia coli. Protein overexpression imposes a burden on metabolism because metabolic pathways must supply building blocks for protein and DNA synthesis. Different E. coli strains have distinct metabolic capacities. In this study, two proteins were overexpressed in four E. coli strains (MG1655(DE3), W3110(DE3), BL21star(DE3), and Rosetta(DE3)), and their effects on metabolic burden were investigated. Metabolomic analysis showed that E. coli strains overexpressing green fluorescent protein had decreased levels of several metabolites, with a positive correlation between the number of reduced metabolites and green fluorescent protein expression levels. Moreover, nucleic acid-related metabolites decreased, indicating a metabolic burden in the E. coli strains, and the growth rate and protein expression levels were improved by supplementation with the five nucleosides. In contrast, two strains overexpressing delta rhodopsin, a microbial membrane rhodopsin from Haloterrigena turkmenica, led to a metabolic burden and decrease in the amino acids Ala, Val, Leu, Ile, Thr, Phe, Asp, and Trp, which are the most frequent amino acids in the delta rhodopsin protein sequence. The metabolic burden caused by protein overexpression was influenced by the metabolic capacity of the host strains and the sequences of the overexpressed proteins. Detailed characterization of the effects of protein expression on the metabolic state of engineered cells using metabolomics will provide insights into improving the production of target compounds.


Assuntos
Escherichia coli , Rodopsina , Proteínas de Fluorescência Verde/genética , Escherichia coli/genética , Metaboloma , Aminoácidos , DNA
6.
Acta Neuropathol Commun ; 12(1): 14, 2024 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-38254245

RESUMO

Neurocutaneous melanosis (NCM) is a rare congenital neurocutaneous syndrome characterized by congenital melanocytic nevus of skin and abnormal proliferation of leptomeningeal melanocytes. Early acquisition of post-zygotic somatic mutations has been postulated to underlie the pathogenesis of NCM. The pathogenesis of NCM remains to be fully elucidated, and treatment options have not been established. Here, we report for the first time, multiregional genomic analyses in a 3-year-old autopsied girl with leptomeningeal melanomatosis associated with NCM, in which a ventriculo-peritoneal (VP) shunt was inserted for the treatment of hydrocephalus. The patient expired six months after the onset due to respiratory failure caused by abdominal dissemination via VP shunt. We performed multiregional exome sequencing to identify genomic differences among brain and abdominal tumors, nevus, and normal tissues. A total of 87 somatic mutations were found in 71 genes, with a significantly large number of gene mutations found in the tumor site. The genetic alterations detected in the nevus were only few and not shared with other sites. Three mutations, namely GNAQ R183Q, S1PR3 G89S and NRAS G12V, considered pathogenic, were found, although S1PR3 mutations have not been previously reported in melanocytic tumors. GNAQ and S1PR3 mutations were shared in both tumor and normal sites. Moreover, the mutant allele frequencies of the two mutations were markedly higher in tumor sites than in normal sites, with copy-neutral loss-of-heterozygosity (CN-LOH) occurring in tumor. NRAS mutation was found only in the abdominal tumor and was thought to be responsible for malignant progression in the present case. Multiregional comprehensive genetic analysis may lead to discovering novel driver mutations associated with tumorigenesis and targeted therapy.


Assuntos
Melanose , Síndromes Neurocutâneas , Nevo , Neoplasias Cutâneas , Feminino , Humanos , Pré-Escolar , Síndromes Neurocutâneas/genética , Mutação de Sentido Incorreto , Neoplasias Cutâneas/genética , Proteínas de Membrana/genética , GTP Fosfo-Hidrolases/genética
7.
J Neurooncol ; 166(2): 273-282, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38227143

RESUMO

PURPOSE: Liquid biopsy of cyst fluid in brain tumors has not been extensively studied to date. The present study was performed to see whether diagnostic genetic alterations found in brain tumor tissue DNA could also be detected in cell-free DNA (cfDNA) of cyst fluid in cystic brain tumors. METHODS: Cyst fluid was obtained from 22 patients undergoing surgery for a cystic brain tumor with confirmed genetic alterations in tumor DNA. Pathological diagnoses based on WHO 2021 classification and diagnostic alterations in the tumor DNA, such as IDH1 R132H and TERT promoter mutation for oligodendrogliomas, were detected by Sanger sequencing. The same alterations were analyzed by both droplet digital PCR (ddPCR) and Sanger sequencing in cyst fluid cfDNA. Additionally, multiplex ligation-dependent probe amplification (MLPA) assays were performed to assess 1p/19q status, presence of CDKN2A loss, PTEN loss and EGFR amplification, to assess whether differentiating between astrocytomas and oligodendrogliomas and grading is possible from cyst fluid cfDNA. RESULTS: Twenty-five genetic alterations were found in 22 tumor samples. All (100%) alterations were detected in cyst fluid cfDNA by ddPCR. Twenty of the 25 (80%) alterations were also detected by Sanger sequencing of cyst fluid cfDNA. Variant allele frequency (VAF) in cyst fluid cfDNA was comparable to that of tumor DNA (R = 0.62, Pearson's correlation). MLPA was feasible in 11 out of 17 (65%) diffuse gliomas, with close correlation of results between tumor DNA and cyst fluid cfDNA. CONCLUSION: Cell-free DNA obtained from cyst fluid in cystic brain tumors is a reliable alternative to tumor DNA when diagnosing brain tumors.


Assuntos
Neoplasias Encefálicas , Ácidos Nucleicos Livres , Oligodendroglioma , Humanos , Oligodendroglioma/diagnóstico , Oligodendroglioma/genética , Oligodendroglioma/patologia , Líquido Cístico , Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patologia , Mutação , Reação em Cadeia da Polimerase Multiplex , DNA
8.
J Gen Appl Microbiol ; 69(4): 185-195, 2024 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-36935115

RESUMO

Although n-butanol (BuOH) is an ideal fuel because of its superior physical properties, it has toxicity to microbes. Previously, a Synechococcus elongatus PCC 7942 derivative strain that produces BuOH from CO2 was developed by introducing six heterologous genes (BUOH-SE strain). To identify the bottleneck in BuOH production, the effects of BuOH production and its toxicity on central metabolism and the photosystem were investigated. Parental (WT) and BUOH-SE strains were cultured under autotrophic conditions. Consistent with the results of a previous study, BuOH production was observed only in the BUOH-SE strain. Isotopically non-stationary 13C-metabolic flux analysis revealed that the CO2 fixation rate was much larger than the BuOH production rate in the BUOH-SE strain (1.70 vs 0.03 mmol gDCW-1 h-1), implying that the carbon flow for BuOH biosynthesis was less affected by the entire flux distribution. No large difference was observed in the flux of metabolism between the WT and BUOH-SE strains. Contrastingly, in the photosystem, the chlorophyll content and maximum O2 evolution rate per dry cell weight of the BUOH-SE strain were decreased to 81% and 43% of the WT strain, respectively. Target proteome analysis revealed that the amounts of some proteins related to antennae (ApcA, ApcD, ApcE, and CpcC), photosystem II (PsbB, PsbU, and Psb28-2), and cytochrome b6f complex (PetB and PetC) in photosystems decreased in the BUOH-SE strain. The activation of photosynthesis would be a novel approach for further enhancing BuOH production in S. elongatus PCC 7942.


Assuntos
1-Butanol , Proteoma , Proteoma/genética , Complexo Citocromos b6f , Dióxido de Carbono , Fotossíntese , Butanóis
9.
Biotechnol Bioeng ; 121(3): 1016-1025, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38116710

RESUMO

Optogenetics is an attractive synthetic biology tool for controlling the metabolic flux distribution. Here, we demonstrated optogenetic flux ratio control of glycolytic pathways consisting of the Embden-Meyerhof-Parnas (EMP), pentose phosphate (PP), and Entner-Doudoroff (ED) pathways by illuminating multicolor lights using blue light-responsive EL222 and green/red light-responsive CcaSR in Escherichia coli. EL222 forms a dimer and binds to a particular DNA sequence under blue light; therefore, target gene expression can be reduced or induced by inserting a recognition sequence into its promoter regions. First, a flux ratio between the PP and ED pathways was controlled by blue light using EL222. After blocking the EMP pathway, the EL222-recognition sequence was inserted between the -35 and -10 regions of gnd to repress the PP flux and was also inserted upstream of the -35 region of edd to induce ED flux. After adjusting light intensity, the PP:ED flux ratios were 60:39% and 29:70% under dark and blue light conditions, respectively. Finally, a CcaSR-based pgi expression system was implemented to control the flux ratio between the EMP and PP + ED pathways by illuminating green/red light. The EMP:PP:ED flux ratios were 80:9:11%, 14:35:51%, and 33:5:62% under green, red, and red and blue light, respectively.


Assuntos
Escherichia coli , Optogenética , Escherichia coli/genética , Escherichia coli/metabolismo , Via de Pentose Fosfato , Glicólise/genética
10.
J Neurosurg Case Lessons ; 6(16)2023 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-37870755

RESUMO

BACKGROUND: Germinomatous germ cell tumor is highly sensitive to chemoradiotherapy; patients are expected to survive for decades. Many radiation-induced malignant gliomas (RIMGs) occur >10 years after radiotherapy. Standard therapy for RIMGs has not been established because of the lesion's rarity, the patient's shorter survival period, and the risk of radiation necrosis by repeat radiation. OBSERVATIONS: Two patients, a 32-year-old man and a 50-year-old man, developed glioblastomas more than 20 years after radiation monotherapy for germinoma with or without mature teratoma. The first patient showed a tumor in the left frontotemporal region with disseminated lesions and died 2 months after partial resection of the tumor without responding to the chemotherapy with temozolomide and bevacizumab. Methylation classifier analysis classified the pathology as closest to diffuse pediatric-type high-grade glioma, Rtk1 subtype. The second patient showed a tumor mass in the brainstem and left cerebellar peduncle, which worsened progressively during chemotherapy with temozolomide and bevacizumab. The tumor transiently responded to stereotactic radiotherapy with the CyberKnife. However, the patient died of RIMG recurrence-related aspiration pneumonia 11 months after the biopsy. Methylation classifier analysis classified the pathology as closest to infratentorial pilocytic astrocytoma. LESSONS: Chemoradiotherapy may improve the survival of patients with RIMGs. Furthermore, molecular features may influence the clinical, locoregional, and pathological features of RIMG.

11.
Clin J Gastroenterol ; 16(6): 859-863, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37608145

RESUMO

A 75-year-old female with a history of Parkinson's disease treatment and hypertension presented at the emergency section with sudden onset of right abdominal pain. Contrast-enhanced computed tomography revealed beaded irregular stenosis and dilation of the superior mesenteric artery (SMA) and an aneurysm in the branch of the pancreaticoduodenal artery (PDA) that communicates with the common hepatic artery and SMA. Additionally, a hematoma had formed in the retroperitoneal space, and extravasation of contrast medium from the pancreaticoduodenal artery aneurysm (PDAA) into the hematoma was observed. The celiac artery (CA) was compressed by the median arcuate ligament; stenosis of the CA at its origin and dilation on the distal side were observed. Based on the imaging findings, it was diagnosed that PDAA was ruptured, SMA developed segmental arterial mediolysis (SAM), and CA developed median arcuate ligament syndrome (MALS). The ruptured PDAA was thought to be caused by SAM combined with MALS. Transcatheter arterial embolization (TAE) was performed for the ruptured PDAA. To the best of our knowledge, there have been no reports of TAE for a ruptured PDAA caused by SAM and MALS. After TAE, the PDAA did not re-rupture.


Assuntos
Aneurisma Roto , Embolização Terapêutica , Síndrome do Ligamento Arqueado Mediano , Feminino , Humanos , Idoso , Síndrome do Ligamento Arqueado Mediano/complicações , Constrição Patológica/terapia , Pâncreas/irrigação sanguínea , Duodeno/irrigação sanguínea , Aneurisma Roto/complicações , Aneurisma Roto/diagnóstico por imagem , Aneurisma Roto/terapia , Embolização Terapêutica/métodos , Artéria Celíaca/diagnóstico por imagem , Hematoma/complicações
13.
Intern Med ; 62(20): 2971-2975, 2023 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-36792186

RESUMO

Plexiform neurofibromas (PNs) occur in approximately 50% of patients with neurofibromatosis type 1 (NF1). PNs are rare in the abdominal cavity and especially rare in hepatobiliary lesions. A 31-year-old man with NF1 had a tumor extending along the celiac artery, superior mesenteric artery, and intrahepatic portal vein. We diagnosed him with diffuse PN based on liver tumor biopsy findings and the tumor form. Because the tumor had invaded along the intrahepatic portal vein, surgical resection was deemed difficult, and the patient was followed up with imaging studies. The patient remained asymptomatic without tumor growth.


Assuntos
Neoplasias Hepáticas , Neurofibroma Plexiforme , Neurofibromatose 1 , Masculino , Humanos , Adulto , Neurofibroma Plexiforme/complicações , Neurofibroma Plexiforme/diagnóstico por imagem , Neurofibroma Plexiforme/cirurgia , Neurofibromatose 1/complicações , Neurofibromatose 1/diagnóstico por imagem , Abdome , Neoplasias Hepáticas/diagnóstico por imagem
14.
Clin J Gastroenterol ; 16(3): 366-371, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36763235

RESUMO

The malignant gastrointestinal endometriosis transformation is represented by endometriosis-associated intestinal tumors. Endometrioid adenocarcinoma and clear cell adenocarcinoma are most common among the endometrial cancers of all organs. Only four cases of mixed serous carcinoma and large cell neuroendocrine carcinoma have been reported, and all these cases originated from the uterus. A 59-year-old woman with a month's history of bloody stools was admitted. She was stable until the hematochezia occurred but is 11 years post-hysterectomy. A circumferential type-3 advanced upper rectum tumor was seen on colonoscopy. Adenocarcinoma was revealed from the forceps biopsies of the type-3 tumor component. Computed tomography showed narrowed lumen with a thickened rectum wall, a continuing mass, and a component on the anorectal side. Swollen lymph nodes were observed around the rectum, but no distant metastatic lymph nodes or organs were found. To treat the lesion, rectal surgical resection with D3 lymph node dissection was performed. Histological examination revealed combined high-grade serous and large cell neuroendocrine carcinomas. Tumor was contiguous to the endometrium in the sub-serosa. Endometriosis was determined to be the origin of both carcinomas. Therefore, endometriosis-associated intestinal tumors should be included in the differential diagnosis when rectal tumors with cystic structures are found post-hysterectomy.


Assuntos
Adenocarcinoma de Células Claras , Carcinoma Endometrioide , Carcinoma Neuroendócrino , Endometriose , Doenças Retais , Neoplasias Retais , Feminino , Humanos , Pessoa de Meia-Idade , Endometriose/complicações , Endometriose/cirurgia , Carcinoma Endometrioide/patologia , Carcinoma Endometrioide/cirurgia , Histerectomia , Adenocarcinoma de Células Claras/etiologia , Adenocarcinoma de Células Claras/cirurgia , Neoplasias Retais/etiologia , Neoplasias Retais/cirurgia , Neoplasias Retais/patologia , Carcinoma Neuroendócrino/cirurgia
15.
ACS Nano ; 17(6): 5561-5569, 2023 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-36820647

RESUMO

One-dimensional (1D) conducting materials are of great interest as potential building blocks for integrated nanocircuits. Ternary 1D transition-metal chalcogenides, consisting of M6X6 wires with intercalated A atoms (M = Mo or W; X = S, Se, or Te; A = alkali or rare metals, etc.), have attracted much attention due to their 1D metallic behavior, superconductivity, and mechanical flexibility. However, the conventional solid-state reaction usually produces micrometer-scale bulk crystals, limiting their potential use as nanoscale conductors. Here we demonstrate a versatile method to fabricate indium (In)-intercalated W6Te6 (In-W6Te6) bundles with a nanoscale thickness. We first prepared micrometer-long, crystalline bundles of van der Waals W6Te6 wires using chemical vapor deposition and intercalated In into the crystal via a vapor-phase reaction. Atomic-resolution electron microscopy revealed that In atoms were surrounded by three adjacent W6Te6 wires. First-principles calculations suggested that their wire-by-wire stacking can transform through postgrowth intercalation. Individual In-W6Te6 bundles exhibited metallic behavior, as theoretically predicted. We further identified the vibrational modes by combining polarized Raman spectroscopy and nonresonant Raman calculations.

16.
Front Artif Intell ; 6: 1039438, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36776421

RESUMO

The discovery of hidden laws in data is the core challenge in many fields, from the natural sciences to the social sciences. However, this task has historically relied on human intuition and experience in many areas, including psychology. Therefore, discovering laws using artificial intelligence (AI) has two significant advantages. First, it makes it possible to detect laws that humans cannot discover. Second, it will help construct more accurate theories. An AI called AI-Feynman was released in a very different field, and it performed impressively. Although AI-Feynman was initially designed to discover laws in physics, it can also work well in psychology. This research aims to examine whether AI-Feynman can be a new data analysis method for inter-temporal choice experiments by testing whether it can discover the hyperbolic discount model as a discount function. An inter-temporal choice experiment was conducted to accomplish these objectives, and the data were input into AI-Feynman. As a result, seven discount function candidates were proposed by AI-Feynman. One candidate was the hyperbolic discount model, which is currently considered the most accurate. The three functions of the root-mean-squared errors were superior to the hyperbolic discount model. Moreover, one of the three candidates was more "hyperbolic" than the standard hyperbolic discount function. These results indicate two things. One is that AI-Feynman can be a new data analysis method for inter-temporal choice experiments. The other is that AI-Feynman can discover discount functions that humans cannot find.

17.
J Biosci Bioeng ; 135(4): 291-297, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36720653

RESUMO

In microbial bioproduction, CO2 emissions via pyruvate dehydrogenase in the Embden-Meyerhof pathway, which converts glucose to acetyl-CoA, is one of the challenges for enhancing carbon yield. The synthetic non-oxidative glycolysis (NOG) pathway transforms glucose into three acetyl-CoA molecules without CO2 emission, making it an attractive module for metabolic engineering. Because the NOG pathway generates no ATP and NADH, it is expected to use a resting cell reaction. Therefore, it is important to characterize the feasibility of the NOG pathway during stationary phase. Here, we experimentally evaluated the in vivo metabolic flow of the NOG pathway in Escherichia coli. An engineered strain was constructed by introducing phosphoketolase from Bifidobacterium adolescentis into E. coli and by deleting competitive reactions. When the strain was cultured in magnesium-starved medium under microaerobic conditions, the carbon yield of acetate, an end-product of the NOG pathway, was six times higher than that of the control strain harboring an empty vector. Based on the mass balance constraints, the NOG flux was estimated to be between 2.89 and 4.64 mmol g-1 h-1, suggesting that the engineered cells can convert glucose through the NOG pathway with enough activity for bioconversion. Furthermore, to expand the application potential of NOG pathway-implemented strains, the theoretical maximum yields of various useful compounds were calculated using flux balance analysis. This suggests that the theoretical maximum yields of not only acetate but also lactam compounds can be increased by introducing the NOG pathway. This information will help in future applications of the NOG pathway.


Assuntos
Dióxido de Carbono , Escherichia coli , Escherichia coli/genética , Escherichia coli/metabolismo , Acetilcoenzima A/metabolismo , Dióxido de Carbono/metabolismo , Glicólise , Engenharia Metabólica , Glucose/metabolismo , Carbono/metabolismo , Acetatos/metabolismo
18.
Dent Mater J ; 42(3): 327-335, 2023 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-36709988

RESUMO

Phosphoric acid (PA) etchants are widely used for the bonding pretreatment of teeth; however, their influences on the bonding between glass-ceramics and resin cement have not been clarified yet. This study investigated the effect of a thickening agent on the bonding strength between feldspar porcelain treated with a PA etchant and resin cement with a silane coupling agent. The experiments were performed using two PA etchants: commercial one and prepared one consisting a PA aqueous solution and poly(ethylene glycol) thickening agent. The samples were evaluated by shear bond strength testing, scanning electron microscopy, and Fourier-transform infrared spectroscopy. The obtained results revealed that the thickening agent adhered to the porcelain surface and inhibited cement bonding. Meanwhile, PA remained on the surface due to the presence of the thickening agent and activated the silane coupling agent. Overall, the PA etchant did not improve the bond durability.


Assuntos
Colagem Dentária , Porcelana Dentária , Cimentos de Resina/química , Silanos/química , Colagem Dentária/métodos , Propriedades de Superfície , Cerâmica/química , Teste de Materiais , Resistência ao Cisalhamento
19.
Biotechnol Prog ; 39(3): e3326, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36700527

RESUMO

In nature, photosynthetic organisms are exposed to fluctuating light, and their physiological systems must adapt to this fluctuation. To maintain homeostasis, these organisms have a light fluctuation photoprotective mechanism, which functions in both photosystems and metabolism. Although the photoprotective mechanisms functioning in the photosystem have been studied, it is unclear how metabolism responds to light fluctuations within a few seconds. In the present study, we investigated the metabolic response of Synechocystis sp. PCC 6803 to light fluctuations using 13 C-metabolic flux analysis. The light intensity and duty ratio were adjusted such that the total number of photons or the light intensity during the low-light phase was equal. Light fluctuations affected cell growth and photosynthetic activity under the experimental conditions. However, metabolic flux distributions and cofactor production rates were not affected by the light fluctuations. Furthermore, the estimated ATP and NADPH production rates in the photosystems suggest that NADPH-consuming electron dissipation occurs under fluctuating light conditions. Although we focused on the water-water cycle as the electron dissipation path, no growth effect was observed in an flv3-disrupted strain under fluctuating light, suggesting that another path contributes to electron dissipation under these conditions.


Assuntos
Luz , Análise do Fluxo Metabólico , Fotossíntese , Synechocystis , Trifosfato de Adenosina/metabolismo , Clorofila/metabolismo , Transporte de Elétrons , Fluorescência , NADP/metabolismo , Oxigênio/metabolismo , Fenótipo , Fotossíntese/efeitos da radiação , Synechocystis/classificação , Synechocystis/crescimento & desenvolvimento , Synechocystis/metabolismo , Synechocystis/efeitos da radiação , Água/metabolismo
20.
Photochem Photobiol ; 99(3): 967-974, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36081379

RESUMO

Two krypton-chloride germicidal excimer lamp units (Care222 TRT-104C11-UI-U3, USHIO Inc.) were installed in the examination room of an ophthalmology department. The irradiation dose was set not to exceed the former (i.e., before 2022) threshold limit value (TLV) (22 mJ cm-2 /8 h) recommended by the ACGIH. Section 1: The eyes and lids of the six ophthalmologists (5 wore glasses for myopic correction) who worked in the room for a mean stay of 6.7 h week-1 were prospectively observed for 12 months. Slitlamp examinations revealed neither acute adverse events such as corneal erosion, conjunctival hyperemia, and lid skin erythema nor chronic adverse events such as pterygium, cataract, or lid tumor. The visual acuity, refractive error, and corneal endothelial cell density remained unchanged during the study. Section 2: The irradiation of samples placed on the table or floor using the same fixtures in the room (5-7.5 mJ cm-2 ) was associated with >99% inhibition of φX174 phage and >90% inhibition of Staphylococcus aureus. In conclusion, no acute or chronic health effects in human participants was observed in a clinical setting of full-room ultraviolet germicidal irradiation by 222-nm lamp units, and high efficacy in deactivation of microorganisms was determined in the same setting.


Assuntos
Raios Ultravioleta , Terapia Ultravioleta , Humanos , Raios Ultravioleta/efeitos adversos , Olho
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