Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 78
Filter
1.
Microbiol Spectr ; : e0183821, 2023 Sep 22.
Article in English | MEDLINE | ID: mdl-37737625

ABSTRACT

In an attempt to identify novel bacterial species, microbiologists have examined a wide range of environmental niches. We describe the serendipitous discovery of a novel gram-negative bacterial species from a different type of extreme niche: a purchased vial of antibiotic. The vial of antibiotic hygromycin B was found to be factory contaminated with a bacterial species, which we designate Pseudomonas hygromyciniae sp. nov. The proposed novel species belongs to the P. fluorescens complex and is most closely related to P. brenneri, P. proteolytica, and P. fluorescens. The type strain Pseudomonas hygromyciniae sp. nov. strain SDM007T (SDM007T) harbors a novel 250 kb megaplasmid which confers resistance to hygromycin B and contains numerous other genes predicted to encode replication and conjugation machinery. SDM007T grows in hygromycin concentrations of up to 5 mg/mL but does not use the antibiotic as a carbon or nitrogen source. While unable to grow at 37°C ruling out its ability to infect humans, it grows and survives at temperatures between 4 and 30°C. SDM007T can infect plants, as demonstrated by the lettuce leaf model, and is highly virulent in the Galleria mellonella infection model but is unable to infect mammalian A549 cells. These findings indicate that commercially manufactured antibiotics represent another extreme environment that may support the growth of novel bacterial species. IMPORTANCE Physical and biological stresses in extreme environments may select for bacteria not found in conventional environments providing researchers with the opportunity to not only discover novel species but to uncover new enzymes, biomolecules, and biochemical pathways. This strategy has been successful in harsh niches such as hot springs, deep ocean trenches, and hypersaline brine pools. Bacteria belonging to the Pseudomonas species are often found to survive in these unusual environments, making them relevant to healthcare, food, and manufacturing industries. Their ability to survive in a variety of environments is mainly due to the high genotypic and phenotypic diversity displayed by this genus. In this study, we discovered a novel Pseudomonas sp. from a desiccated environment of a sealed antibiotic bottle that was considered sterile. A close genetic relationship with its phylogenetic neighbors reiterated the need to use not just DNA-based tools but also biochemical characteristics to accurately classify this organism.

2.
Nat Rev Neurol ; 19(5): 289-304, 2023 05.
Article in English | MEDLINE | ID: mdl-37055617

ABSTRACT

Current therapies for multiple sclerosis (MS) reduce both relapses and relapse-associated worsening of disability, which is assumed to be mainly associated with transient infiltration of peripheral immune cells into the central nervous system (CNS). However, approved therapies are less effective at slowing disability accumulation in patients with MS, in part owing to their lack of relevant effects on CNS-compartmentalized inflammation, which has been proposed to drive disability. Bruton tyrosine kinase (BTK) is an intracellular signalling molecule involved in the regulation of maturation, survival, migration and activation of B cells and microglia. As CNS-compartmentalized B cells and microglia are considered central to the immunopathogenesis of progressive MS, treatment with CNS-penetrant BTK inhibitors might curtail disease progression by targeting immune cells on both sides of the blood-brain barrier. Five BTK inhibitors that differ in selectivity, strength of inhibition, binding mechanisms and ability to modulate immune cells within the CNS are currently under investigation in clinical trials as a treatment for MS. This Review describes the role of BTK in various immune cells implicated in MS, provides an overview of preclinical data on BTK inhibitors and discusses the (largely preliminary) data from clinical trials.


Subject(s)
Multiple Sclerosis, Chronic Progressive , Multiple Sclerosis , Humans , Central Nervous System/pathology , Signal Transduction
3.
Biotechnol J ; 18(4): e2200535, 2023 Apr.
Article in English | MEDLINE | ID: mdl-36723451

ABSTRACT

Engineered Saccharomyces cerevisiae expressing a lactic acid dehydrogenase can metabolize pyruvate into lactic acid. However, three pyruvate decarboxylase (PDC) isozymes drive most carbon flux toward ethanol rather than lactic acid. Deletion of endogenous PDCs will eliminate ethanol production, but the resulting strain suffers from C2 auxotrophy and struggles to complete a fermentation. Engineered yeast assimilating xylose or cellobiose produce lactic acid rather than ethanol as a major product without the deletion of any PDC genes. We report here that sugar flux, but not sensing, contributes to the partition of flux at the pyruvate branch point in S. cerevisiae expressing the Rhizopus oryzae lactic acid dehydrogenase (LdhA). While the membrane glucose sensors Snf3 and Rgt2 did not play any direct role in the option of predominant product, the sugar assimilation rate was strongly correlated to the partition of flux at pyruvate: fast sugar assimilation favors ethanol production while slow sugar assimilation favors lactic acid. Applying this knowledge, we created an engineered yeast capable of simultaneously converting glucose and xylose into lactic acid, increasing lactic acid production to approximately 17 g L-1 from the 12 g L-1 observed during sequential consumption of sugars. This work elucidates the carbon source-dependent effects on product selection in engineered yeast.


Subject(s)
Glucose , Saccharomyces cerevisiae , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae/metabolism , Glucose/metabolism , Lactic Acid , Xylose/metabolism , Pyruvic Acid/metabolism , Ethanol/metabolism , Fermentation , Oxidoreductases/metabolism
4.
Bioresour Technol ; 346: 126614, 2022 Feb.
Article in English | MEDLINE | ID: mdl-34954359

ABSTRACT

Lignocellulosic biomass-derived fuels, chemicals, and materials are promising sustainable solutions to replace the current petroleum-based production. The direct microbial conversion of thermos-chemically pretreated lignocellulosic biomass is hampered by the presence of highly toxic chemical compounds. Also, thermo-catalytic upgrading of lignocellulosic biomass generates wastewater that contains heterogeneous toxic chemicals, a mixture of unutilized carbon. Metabolic engineering efforts have primarily focused on the conversion of carbohydrates in lignocellulose biomass; substantial opportunities exist to harness value from toxic lignocellulose-derived toxic compounds. This article presents the comprehensive metabolic routes and tolerance mechanisms to develop robust synthetic microbial cell factories to valorize the highly toxic compounds to advanced-platform chemicals. The obtained platform chemicals can be used to manufacture high-value biopolymers and biomaterials via a hybrid biochemical approach for replacing petroleum-based incumbents. The proposed strategy enables a sustainable bio-based materials economy by microbial biofunneling of lignocellulosic biomass-derived toxic molecules, an untapped biogenic carbon.


Subject(s)
Lignin , Metabolic Engineering , Biomass , Catalysis
5.
Int J Inflam ; 2021: 3963659, 2021.
Article in English | MEDLINE | ID: mdl-34691383

ABSTRACT

Idiopathic pulmonary fibrosis (IPF) is a disease with an unknown etiology mainly characterized by a progressive decline of lung function due to the scarring of the tissue deep in the lungs. The overall survival after diagnosis remains low between 3 and 5 years. IPF is a heterogeneous disease and much progress has been made in the past decade in understanding the disease mechanisms that contributed to the development of two new drugs, pirfenidone and nintedanib, which improved the therapeutic management of the disease. The understanding of the cofactors and comorbidities of IPF also contributed to improved management of the disease outcome. In the present review, we evaluate scientific evidence which indicates IPF as a risk factor for other diseases based on the complexity of molecular and cellular mechanisms involved in the disease development and of comorbidities. We conclude from the existing literature that while much progress has been made in understating the mechanisms involved in IPF development, further studies are still necessary to fully understand IPF pathogenesis which will contribute to the identification of novel therapeutic targets for IPF management as well as other diseases for which IPF is a major risk factor.

6.
Int J Mol Sci ; 22(18)2021 Sep 10.
Article in English | MEDLINE | ID: mdl-34575975

ABSTRACT

Several classes of immunomodulators are used for treating relapsing-remitting multiple sclerosis (RRMS). Most of these disease-modifying therapies, except teriflunomide, carry the risk of progressive multifocal leukoencephalopathy (PML), a severely debilitating, often fatal virus-induced demyelinating disease. Because teriflunomide has been shown to have antiviral activity against DNA viruses, we investigated whether treatment of cells with teriflunomide inhibits infection and spread of JC polyomavirus (JCPyV), the causative agent of PML. Treatment of choroid plexus epithelial cells and astrocytes with teriflunomide reduced JCPyV infection and spread. We also used droplet digital PCR to quantify JCPyV DNA associated with extracellular vesicles isolated from RRMS patients. We detected JCPyV DNA in all patients with confirmed PML diagnosis (n = 2), and in six natalizumab-treated (n = 12), two teriflunomide-treated (n = 7), and two nonimmunomodulated (n = 2) patients. Of the 21 patients, 12 (57%) had detectable JCPyV in either plasma or serum. CSF was uniformly negative for JCPyV. Isolation of extracellular vesicles did not increase the level of detection of JCPyV DNA versus bulk unprocessed biofluid. Overall, our study demonstrated an effect of teriflunomide inhibiting JCPyV infection and spread in glial and choroid plexus epithelial cells. Larger studies using patient samples are needed to correlate these in vitro findings with patient data.


Subject(s)
Crotonates/pharmacology , DNA Viruses/drug effects , Hydroxybutyrates/pharmacology , Leukoencephalopathy, Progressive Multifocal/drug therapy , Multiple Sclerosis, Relapsing-Remitting/drug therapy , Neuroglia/drug effects , Nitriles/pharmacology , Toluidines/pharmacology , Astrocytes/drug effects , Astrocytes/virology , Cell Line , Choroid Plexus/drug effects , Choroid Plexus/virology , DNA Viruses/pathogenicity , Demyelinating Diseases/drug therapy , Demyelinating Diseases/pathology , Demyelinating Diseases/virology , Epithelial Cells/drug effects , Epithelial Cells/virology , Extracellular Vesicles/drug effects , Extracellular Vesicles/virology , Humans , Immunologic Factors/adverse effects , Immunologic Factors/therapeutic use , JC Virus/drug effects , JC Virus/pathogenicity , Leukoencephalopathy, Progressive Multifocal/chemically induced , Leukoencephalopathy, Progressive Multifocal/pathology , Leukoencephalopathy, Progressive Multifocal/virology , Multiple Sclerosis, Relapsing-Remitting/genetics , Multiple Sclerosis, Relapsing-Remitting/pathology , Multiple Sclerosis, Relapsing-Remitting/virology , Neuroglia/virology , Virus Diseases/drug therapy , Virus Diseases/genetics , Virus Diseases/virology
7.
Lancet Neurol ; 20(9): 729-738, 2021 09.
Article in English | MEDLINE | ID: mdl-34418400

ABSTRACT

BACKGROUND: Tolebrutinib is an oral, CNS-penetrant, irreversible inhibitor of Bruton's tyrosine kinase, an enzyme expressed in B lymphocytes and myeloid cells including microglia, which are major drivers of inflammation in multiple sclerosis. We aimed to determine the dose-response relationship between tolebrutinib and the reduction in new active brain MRI lesions in patients with relapsing multiple sclerosis. METHODS: We did a 16-week, phase 2b, randomised, double-blind, placebo-controlled, crossover, dose-finding trial at 40 centres (academic sites, specialty clinics, and general neurology centres) in ten countries in Europe and North America. Eligible participants were adults aged 18-55 years with diagnosed relapsing multiple sclerosis (either relapsing-remitting or relapsing secondary progressive multiple sclerosis), and one or more of the following criteria: at least one relapse within the previous year, at least two relapses within the previous 2 years, or at least one active gadolinium-enhancing brain lesion in the 6 months before screening. Exclusion criteria included a diagnosis of primary progressive multiple sclerosis or a diagnosis of secondary progressive multiple sclerosis without relapse. We used a two-step randomisation process to randomly assign eligible participants (1:1) to two cohorts, then further randomly assign participants in each cohort (1:1:1:1) to four tolebrutinib dose groups (5, 15, 30, and 60 mg administered once daily as an oral tablet). Cohort 1 received tolebrutinib for 12 weeks, then matched placebo (ie, identical looking tablets) for 4 weeks; cohort 2 received 4 weeks of placebo followed by 12 weeks of tolebrutinib. Participants and investigators were masked for dose and tolebrutinib-placebo administration sequence; investigators, study team members, and study participants did not have access to unmasked data. MRI scans were done at screening and every 4 weeks over 16 weeks. The primary efficacy endpoint was the number of new gadolinium-enhancing lesions detected on the scan done after 12 weeks of tolebrutinib treatment (assessed at week 12 for cohort 1 and week 16 for cohort 2), relative to the scan done 4 weeks previously, and compared with the lesions accumulated during 4 weeks of placebo run-in period in cohort 2. Efficacy data were analysed in a modified intention-to-treat population, using a two-step multiple comparison procedure with modelling analysis. Safety was assessed for all participants who received at least one dose of study drug. This trial is registered with ClinicalTrials.gov (NCT03889639), EudraCT (2018-003927-12), and WHO (U1111-1220-0572), and has been completed. FINDINGS: Between May 14, 2019, and Jan 2, 2020, we enrolled and randomly assigned 130 participants to tolebrutinib: 33 to 5 mg, 32 to 15 mg, 33 to 30 mg, and 32 to 60 mg. 129 (99%) completed the treatment regimen and 126 were included in the primary analysis. At treatment week 12, there was a dose-dependent reduction in the number of new gadolinium-enhancing lesions (mean [SD] lesions per patient: placebo, 1·03 [2·50]; 5 mg, 1·39 [3·20]; 15 mg, 0·77 [1·48]; 30 mg, 0·76 [3·31]; 60 mg, 0·13 [0·43]; p=0·03). One serious adverse event was reported (one patient in the 60 mg group was admitted to hospital because of a multiple sclerosis relapse). The most common non-serious adverse event during tolebrutinib treatment was headache (in one [3%] of 33 in the 5 mg group; three [9%] of 32 in the 15 mg group; one [3%] of 33 in the 30 mg group; and four [13%] of 32 in the 60 mg group). No safety-related discontinuations or treatment-related deaths occurred. INTERPRETATION: 12 weeks of tolebrutinib treatment led to a dose-dependent reduction in new gadolinium-enhancing lesions, the 60 mg dose being the most efficacious, and the drug was well tolerated. Reduction of acute inflammation, combined with the potential to modulate the immune response within the CNS, provides a scientific rationale to pursue phase 3 clinical trials of tolebrutinib in patients with relapsing and progressive forms of multiple sclerosis. FUNDING: Sanofi.


Subject(s)
Agammaglobulinaemia Tyrosine Kinase/antagonists & inhibitors , Central Nervous System/drug effects , Inflammation/drug therapy , Multiple Sclerosis, Relapsing-Remitting/drug therapy , Outcome Assessment, Health Care , Protein Kinase Inhibitors/pharmacology , Adult , Central Nervous System/diagnostic imaging , Central Nervous System/immunology , Central Nervous System/pathology , Cross-Over Studies , Dose-Response Relationship, Drug , Double-Blind Method , Female , Humans , Inflammation/diagnostic imaging , Inflammation/immunology , Inflammation/pathology , Magnetic Resonance Imaging , Male , Middle Aged , Multiple Sclerosis, Relapsing-Remitting/diagnostic imaging , Multiple Sclerosis, Relapsing-Remitting/immunology , Multiple Sclerosis, Relapsing-Remitting/pathology , Protein Kinase Inhibitors/administration & dosage , Protein Kinase Inhibitors/adverse effects , Protein Kinase Inhibitors/pharmacokinetics , Recurrence , Young Adult
8.
BMJ Case Rep ; 14(5)2021 May 24.
Article in English | MEDLINE | ID: mdl-34031078

ABSTRACT

A man in his 50s with neutropenic fever and multifocal lung opacities was diagnosed with a viral pneumonia. A small number of bacteria grown from bronchoalveolar lavage fluid collected during a repeat bronchoscopy were initially identified as Pseudomonas aeruginosa by VITEK-2 and mass spectrometry platforms. Whole-genome sequencing, however, subsequently demonstrated that the bacteria were Pseudomonas nitroreducens, representing the first known case of P. nitroreducens cultured from human lungs.


Subject(s)
Pneumonia , Pseudomonas Infections , Bronchoalveolar Lavage Fluid , Humans , Lung/diagnostic imaging , Male , Pseudomonas , Pseudomonas Infections/diagnosis , Pseudomonas Infections/drug therapy , Pseudomonas aeruginosa
9.
Article in English | MEDLINE | ID: mdl-33837058

ABSTRACT

OBJECTIVE: To test the hypothesis that teriflunomide can reduce ex vivo spontaneous proliferation of peripheral blood mononuclear cells (PBMCs) from patients with human T-cell lymphotropic virus type 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP). METHODS: PBMCs from patients with HAM/TSP were cultured in the presence and absence of teriflunomide and assessed for cell viability, lymphocyte proliferation, activation markers, HTLV-1 tax and HTLV-1 hbz messenger ribonucleic acid (mRNA) expression, and HTLV-1 Tax protein expression. RESULTS: In culture, teriflunomide did not affect cell viability. A concentration-dependent reduction in spontaneous proliferation of PBMCs was observed with 25 µM (38.3% inhibition), 50 µM (65.8% inhibition), and 100 µM (90.7% inhibition) teriflunomide. The inhibitory effects of teriflunomide were detected in both CD8+ and CD4+ T-cell subsets, which are involved in the immune response to HTLV-1 infection and the pathogenesis of HAM/TSP. There was no significant change in HTLV-1 proviral load (PVL) or tax mRNA/Tax protein expression in these short-term cultures, but there was a significant reduction of HTLV-1 PVL due to inhibition of proliferation of CD4+ T cells obtained from a subset of patients with HAM/TSP. CONCLUSIONS: These results suggest that teriflunomide inhibits abnormal T-cell proliferation associated with HTLV-1 infection and may have potential as a therapeutic option in patients with HAM/TSP.


Subject(s)
Crotonates/pharmacology , Hydroxybutyrates/pharmacology , Leukocytes, Mononuclear/drug effects , Nitriles/pharmacology , Paraparesis, Tropical Spastic/drug therapy , Toluidines/pharmacology , Adult , Aged , Cell Proliferation/drug effects , Cell Survival/drug effects , Female , Gene Products, tax/metabolism , HTLV-I Infections/complications , Human T-lymphotropic virus 1/genetics , Humans , Male , Middle Aged , Primary Cell Culture , RNA, Messenger/metabolism , T-Lymphocyte Subsets/drug effects
10.
J Labelled Comp Radiopharm ; 63(11): 482-487, 2020 09.
Article in English | MEDLINE | ID: mdl-32726870

ABSTRACT

Bruton's tyrosine kinase (BTK) is a key component in the B-cell receptor signaling pathway and is consequently a target for in vivo imaging of B-cell malignancies as well as in multiple sclerosis (MS) with positron emission tomography (PET). A recent Phase 2b study with Sanofi's BTK inhibitor, Tolebrutinib (also known as [a.k.a.] SAR442168, PRN2246, or BTK'168) showed significantly reduced disease activity associated with MS. Herein, we report the radiosynthesis of [11 C]Tolebrutinib ([11 C]5) as a potential PET imaging agent for BTK. The N-[11 C]acrylamide moiety of [11 C]5 was labeled by 11 C-carbonylation starting from [11 C]CO, iodoethylene, and the secondary amine precursor via a novel palladium-NiXantphos-mediated carbonylation protocol, and the synthesis was fully automated using a commercial carbon-11 synthesis platform (TracerMaker™, Scansys Laboratorieteknik). [11 C]5 was obtained in a decay-corrected radiochemical yield of 37 ± 2% (n = 5, relative to starting [11 C]CO activity) in >99% radiochemical purity, with an average molar activity of 45 GBq/µmol (1200 mCi/µmol). We envision that this methodology will be generally applicable for the syntheses of labeled N-acrylamides.


Subject(s)
Agammaglobulinaemia Tyrosine Kinase/antagonists & inhibitors , Carbon Radioisotopes/chemistry , Palladium/chemistry , Protein Kinase Inhibitors/chemistry , Protein Kinase Inhibitors/chemical synthesis , Tolmetin/chemistry , Tolmetin/chemical synthesis , Chemistry Techniques, Synthetic , Positron-Emission Tomography , Protein Kinase Inhibitors/pharmacology , Radiochemistry , Tolmetin/pharmacology
11.
J Neuroinflammation ; 17(1): 9, 2020 Jan 08.
Article in English | MEDLINE | ID: mdl-31915017

ABSTRACT

BACKGROUND: The multi-drug resistance transporter ABCG2, a member of the ATP-binding cassette (ABC) transporter family, mediates the efflux of different immunotherapeutics used in multiple sclerosis (MS), e.g., teriflunomide (teri), cladribine, and mitoxantrone, across cell membranes and organelles. Hence, the modulation of ABCG2 activity could have potential therapeutic implications in MS. In this study, we aimed at investigating the functional impact of abcg2 modulation on teri-induced effects in vitro and in vivo. METHODS: T cells from C57BL/6 J wild-type (wt) and abcg2-knockout (KO) mice were treated with teri at different concentrations with/without specific abcg2-inhibitors (Ko143; Fumitremorgin C) and analyzed for intracellular teri concentration (HPLC; LS-MS/MS), T cell apoptosis (annexin V/PI), and proliferation (CSFE). Experimental autoimmune encephalomyelitis (EAE) was induced in C57BL/6J by active immunization with MOG35-55/CFA. Teri (10 mg/kg body weight) was given orally once daily after individual disease onset. abcg2-mRNA expression (spinal cord, splenic T cells) was analyzed using qRT-PCR. RESULTS: In vitro, intracellular teri concentration in T cells was 2.5-fold higher in abcg2-KO mice than in wt mice. Teri-induced inhibition of T cell proliferation was two fold increased in abcg2-KO cells compared to wt cells. T cell apoptosis demonstrated analogous results with 3.1-fold increased apoptosis after pharmacological abcg2-inhibition in wt cells. abcg2-mRNA was differentially regulated during different phases of EAE within the central nervous system and peripheral organs. In vivo, at a dosage not efficacious in wt animals, teri treatment ameliorated clinical EAE in abcg2-KO mice which was accompanied by higher spinal cord tissue concentrations of teri. CONCLUSION: Functional relevance of abcg2 modulation on teri effects in vitro and in vivo warrants further investigation as a potential determinant of interindividual treatment response in MS, with potential implications for other immunotherapies.


Subject(s)
ATP Binding Cassette Transporter, Subfamily G, Member 2/physiology , Crotonates/therapeutic use , Disease Models, Animal , Immunotherapy/methods , Multiple Sclerosis/immunology , T-Lymphocytes/immunology , Toluidines/therapeutic use , Animals , Crotonates/pharmacology , Female , Humans , Hydroxybutyrates , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Multiple Sclerosis/drug therapy , Nitriles , Rats , T-Lymphocytes/drug effects , Toluidines/pharmacology
12.
Bioorg Med Chem ; 28(1): 115232, 2020 01 01.
Article in English | MEDLINE | ID: mdl-31818630

ABSTRACT

Glucose flux through glucokinase (GK) controls insulin release from the pancreas in response to high levels of glucose. Flux through GK is also responsible for reducing hepatic glucose output. Since many individuals with type 2 diabetes appear to have an inadequacy or defect in one or both of these processes, identifying compounds that can activate GK could provide a therapeutic benefit. Herein we report the further structure activity studies of a novel series of glucokinase activators (GKA). These studies led to the identification of pyridine 72 as a potent GKA that lowered post-prandial glucose in normal C57BL/6J mice, and after 14d dosing in ob/ob mice.


Subject(s)
Enzyme Activators/chemistry , Glucokinase/chemistry , Hypoglycemic Agents/chemistry , Animals , Binding Sites , Blood Glucose/analysis , Crystallography, X-Ray , Diabetes Mellitus, Experimental/drug therapy , Diabetes Mellitus, Experimental/metabolism , Diabetes Mellitus, Experimental/pathology , Drug Design , Drug Evaluation, Preclinical , Enzyme Activators/metabolism , Enzyme Activators/therapeutic use , Glucokinase/metabolism , Glucose Tolerance Test , Hypoglycemic Agents/metabolism , Hypoglycemic Agents/therapeutic use , Kinetics , Mice , Mice, Inbred C57BL , Molecular Dynamics Simulation , Structure-Activity Relationship , Thiadiazoles/chemistry , Thiadiazoles/metabolism
13.
3 Biotech ; 9(10): 367, 2019 Oct.
Article in English | MEDLINE | ID: mdl-31588391

ABSTRACT

In a previously engineered Saccharomyces cerevisiae recombinant, the cellobiose fermentation rate was significantly lower than the glucose fermentation rate. Thus, we implemented a genome-wide perturbation library to find gene targets for improving the cellobiose fermentation capability of the yeast strain. Unexpectedly, we discovered a transformant that contained an additional ß-glucosidase gene (gh1-1), possibly through homologous recombination between the plasmids. The additional ß-glucosidase led to the fastest cellobiose fermentation activity among all the transformants evaluated, and the strain demonstrated significantly higher ß-glucosidase activity than the control strain, especially during the initial exponential growth phase. The present work revealed the benefit of the extra gh1-1 copy for efficient cellobiose fermentation in the engineered S. cerevisiae strain.

14.
FEMS Yeast Res ; 19(6)2019 09 01.
Article in English | MEDLINE | ID: mdl-31505595

ABSTRACT

Microorganisms have evolved to produce specific end products for many reasons, including maintaining redox balance between NAD+ and NADH. The yeast Saccharomyces cerevisiae, for example, produces ethanol as a primary end product from glucose for the regeneration of NAD+. Engineered S. cerevisiae strains have been developed to ferment lignocellulosic sugars, such as xylose, to produce lactic acid by expression of a heterologous lactate dehydrogenase (ldhA from Rhizopus oryzae) without genetic perturbation to the native ethanol pathway. Surprisingly, the engineered yeast strains predominantly produce ethanol from glucose, but produce lactic acid as the major product from xylose. Here, we provide initial evidence that the shift in product formation from ethanol to lactic acid during xylose fermentation is at least partially dependent on the presence of functioning monocarboxylate transporter genes/proteins, including JEN1 and ADY2, which are downregulated and unstable in the presence of glucose, but upregulated/stable on xylose. Future yeast metabolic engineering studies may find the feedstock/carbon selection, such as xylose, an important step toward improving the yield of target end products.


Subject(s)
L-Lactate Dehydrogenase/metabolism , Lactic Acid/metabolism , Membrane Transport Proteins/genetics , Metabolic Engineering , Rhizopus/enzymology , Saccharomyces cerevisiae Proteins/genetics , Saccharomyces cerevisiae/metabolism , Xylose/metabolism , Down-Regulation , Ethanol/metabolism , Fermentation , Fungal Proteins/genetics , Fungal Proteins/metabolism , Gene Expression , Glucose/metabolism , L-Lactate Dehydrogenase/genetics , Monocarboxylic Acid Transporters/genetics , Rhizopus/genetics , Saccharomyces cerevisiae/genetics , Sequence Deletion , Symporters/genetics , Transgenes
15.
Sci Transl Med ; 11(490)2019 05 01.
Article in English | MEDLINE | ID: mdl-31043571

ABSTRACT

Interference with immune cell proliferation represents a successful treatment strategy in T cell-mediated autoimmune diseases such as rheumatoid arthritis and multiple sclerosis (MS). One prominent example is pharmacological inhibition of dihydroorotate dehydrogenase (DHODH), which mediates de novo pyrimidine synthesis in actively proliferating T and B lymphocytes. Within the TERIDYNAMIC clinical study, we observed that the DHODH inhibitor teriflunomide caused selective changes in T cell subset composition and T cell receptor repertoire diversity in patients with relapsing-remitting MS (RRMS). In a preclinical antigen-specific setup, DHODH inhibition preferentially suppressed the proliferation of high-affinity T cells. Mechanistically, DHODH inhibition interferes with oxidative phosphorylation (OXPHOS) and aerobic glycolysis in activated T cells via functional inhibition of complex III of the respiratory chain. The affinity-dependent effects of DHODH inhibition were closely linked to differences in T cell metabolism. High-affinity T cells preferentially use OXPHOS during early activation, which explains their increased susceptibility toward DHODH inhibition. In a mouse model of MS, DHODH inhibitory treatment resulted in preferential inhibition of high-affinity autoreactive T cell clones. Compared to T cells from healthy controls, T cells from patients with RRMS exhibited increased OXPHOS and glycolysis, which were reduced with teriflunomide treatment. Together, these data point to a mechanism of action where DHODH inhibition corrects metabolic disturbances in T cells, which primarily affects profoundly metabolically active high-affinity T cell clones. Hence, DHODH inhibition may promote recovery of an altered T cell receptor repertoire in autoimmunity.


Subject(s)
Crotonates/therapeutic use , Mitochondria/metabolism , Multiple Sclerosis/drug therapy , Multiple Sclerosis/immunology , T-Lymphocytes/immunology , Toluidines/therapeutic use , Aerobiosis/drug effects , Animals , Cell Proliferation/drug effects , Cell Respiration/drug effects , Crotonates/pharmacology , Dihydroorotate Dehydrogenase , Electron Transport Complex III/metabolism , Energy Metabolism/drug effects , Gene Expression Regulation/drug effects , Glycolysis/drug effects , Humans , Hydroxybutyrates , Lymphocyte Activation/drug effects , Lymphocyte Subsets/drug effects , Lymphocyte Subsets/immunology , Mitochondria/drug effects , Multiple Sclerosis/genetics , Multiple Sclerosis/pathology , Multiple Sclerosis, Relapsing-Remitting/immunology , Nitriles , Oxidative Phosphorylation/drug effects , Oxidoreductases Acting on CH-CH Group Donors/antagonists & inhibitors , Oxidoreductases Acting on CH-CH Group Donors/metabolism , Receptors, Antigen, T-Cell/metabolism , T-Lymphocytes/drug effects , Toluidines/pharmacology
16.
AMIA Annu Symp Proc ; 2019: 1197-1206, 2019.
Article in English | MEDLINE | ID: mdl-32308917

ABSTRACT

We investigated the cognitive load effect of a trainer providing surgical instruction by pointing/drawing over laparoscopic video to a trainee. Results showed that while cognitive load is higher overall with the use of the instructional system, there is a decrease by the second experience of being instructed by the Virtual Pointer. Further analysis showed that trainees were more likely to perform the surgical task and watch/listen to the trainer's instruction at the same time when the instructional system was used. This is thought to be an indication of more efficient communication when using the instructional system. Thus, although there is a small cognitive overload with the instructional system initially, the more efficient communication allows trainees to better integrate the knowledge and instructions being conveyed into the actions they must perform - indicating a better learning environment.


Subject(s)
Cognition , Computer Simulation , General Surgery/education , Laparoscopy/education , Clinical Competence , Communication , Humans , Teaching , Teaching Materials , Video Recording
17.
Appl Microbiol Biotechnol ; 102(18): 8121-8133, 2018 Sep.
Article in English | MEDLINE | ID: mdl-30027490

ABSTRACT

Engineered S. cerevisiae employing the xylose reductase pathway enables efficient xylose valorization to fuels and chemicals. However, toxicity of thermochemically pretreated biomass hydrolysate on S. cerevisiae is one of the key technical challenges to upgrade biomass-derived sugars including xylose and glucose into high-value products. We investigated the effect of glycolaldehyde, one of the biomass-derived highly toxic aldehyde compounds, and its combinatorial inhibitory effect with other major fermentation inhibitors commonly found in plant hydrolysate such as methylglyoxal, 5-HMF, furfural, vanillin, and acetic acid on engineered xylose-fermenting S. cerevisiae in xylose and/or glucose media. We elucidated that glycolaldehyde and methylglyoxal are the key inhibitory short-aliphatic aldehydes on engineered xylose-fermenting S. cerevisiae in xylose-containing medium. Indeed, the degree of toxicity of these tested fermentation inhibitors varies with the sole carbon source of the medium. We demonstrate that genome integration of an extra copy of autologous GRE2 with its native promotor substantially improved the toxic tolerance of engineered xylose-fermenting S. cerevisiae to major inhibitory compounds including glycolaldehyde in the xylose-containing medium, and xylose-rich, lignocellulosic hydrolysate derived from Miscanthus giganteus, and concurrently improved the ethanol fermentation profile. Outcomes of this study will aid the development of next-generation robust S. cerevisiae strains for efficient fermentation of hexose and pentose sugars found in biomass hydrolysate.


Subject(s)
Acetaldehyde/analogs & derivatives , Metabolic Engineering , Oxidoreductases/genetics , Saccharomyces cerevisiae Proteins/genetics , Saccharomyces cerevisiae/enzymology , Xylose/metabolism , Acetaldehyde/metabolism , Biomass , Fermentation , Glucose/metabolism , Oxidoreductases/metabolism , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae/growth & development , Saccharomyces cerevisiae/metabolism , Saccharomyces cerevisiae Proteins/metabolism
18.
Biotechnol Bioeng ; 115(12): 2859-2868, 2018 12.
Article in English | MEDLINE | ID: mdl-30011361

ABSTRACT

Simultaneous saccharification and fermentation (SSF) of cellulose via engineered Saccharomyces cerevisiae is a sustainable solution to valorize cellulose into fuels and chemicals. In this study, we demonstrate the feasibility of direct conversion of cellulose into ethanol and a biodegradable surfactant, ethyl-ß-d-glucoside, via an engineered yeast strain (i.e., strain EJ2) expressing heterologous cellodextrin transporter (CDT-1) and intracellular ß-glucosidase (GH1-1) originating from Neurospora crassa. We identified the formation of ethyl-ß-d-glucoside in SSF of cellulose by the EJ2 strain owing to transglycosylation activity of GH1-1. The EJ2 strain coproduced 0.34 ± 0.03 g ethanol/g cellulose and 0.06 ± 0.00 g ethyl-ß-d-glucoside/g cellulose at a rate of 0.30 ± 0.02 g·L-1 ·h-1 and 0.09 ± 01 g·L-1 ·h-1 , respectively, during the SSF of Avicel PH-101 cellulose, supplemented only with Celluclast 1.5 L. Herein, we report a possible coproduction of a value-added chemical (alkyl-glucosides) during SSF of cellulose exploiting the transglycosylation activity of GH1-1 in engineered S. cerevisiae. This coproduction could have a substantial effect on the overall technoeconomic feasibility of theSSF of cellulose.


Subject(s)
Cellulose/metabolism , Ethanol/metabolism , Glucosides/metabolism , Metabolic Engineering/methods , Saccharomyces cerevisiae/genetics , Fermentation , Fungal Proteins/genetics , Fungal Proteins/metabolism , Glucosides/genetics , Glycosylation , Neurospora crassa/enzymology , Neurospora crassa/genetics , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Saccharomyces cerevisiae/enzymology , Saccharomyces cerevisiae/metabolism
19.
Int J Comput Assist Radiol Surg ; 13(9): 1463-1472, 2018 Sep.
Article in English | MEDLINE | ID: mdl-29796835

ABSTRACT

PURPOSE: To assess a virtual pointer in supporting surgical trainees' development of professional vision in laparoscopic surgery. METHODS: We developed a virtual pointing and telestration system utilizing the Microsoft Kinect movement sensor as an overlay for any imagine system. Training with the application was compared to a standard condition, i.e., verbal instruction with un-mediated gestures, in a laparoscopic training environment. Seven trainees performed four simulated laparoscopic tasks guided by an experienced surgeon as the trainer. Trainee performance was subjectively assessed by the trainee and trainer, and objectively measured by number of errors, time to task completion, and economy of movement. RESULTS: No significant differences in errors and time to task completion were obtained between virtual pointer and standard conditions. Economy of movement in the non-dominant hand was significantly improved when using virtual pointer ([Formula: see text]). The trainers perceived a significant improvement in trainee performance in virtual pointer condition ([Formula: see text]), while the trainees perceived no difference. The trainers' perception of economy of movement was similar between the two conditions in the initial three runs and became significantly improved in virtual pointer condition in the fourth run ([Formula: see text]). CONCLUSIONS: Results show that the virtual pointer system improves the trainer's perception of trainee's performance and this is reflected in the objective performance measures in the third and fourth training runs. The benefit of a virtual pointing and telestration system may be perceived by the trainers early on in training, but this is not evident in objective trainee performance until further mastery has been attained. In addition, the performance improvement of economy of motion specifically shows that the virtual pointer improves the adoption of professional vision- improved ability to see and use laparoscopic video results in more direct instrument movement.


Subject(s)
Clinical Competence , Computer Simulation , Computer-Assisted Instruction , Laparoscopy/education , User-Computer Interface , Female , Humans , Laparoscopy/methods , Male
20.
Article in English | MEDLINE | ID: mdl-29843394

ABSTRACT

Kidney cancer ranks among the top 10 cancers in the United States. Although it affects both male and female populations, it is more common in males. The prevalence rate of renal cell carcinoma (RCC), which represents about 85% of kidney cancers, has been increasing gradually in many developed countries. Family history has been considered as one of the most relevant risk factors for kidney cancer, although most forms of an inherited predisposition for RCC only account for less than four percent. Lifestyle and other factors such as occupational exposure, high blood pressure, poor diet, and heavy cigarette smoking are highly associated with its incidence and mortality rates. In the United States, White populations have the lowest prevalence of RCC compared to other ethnic groups, while Black Americans suffer disproportionally from the adverse effects of RCC. Hence, this review article aims at identifying the major risk factors associated with RCC and highlighting the new therapeutic approaches for its control/prevention. To achieve this specific aim, articles in peer-reviewed journals with a primary focus on risk factors related to kidney cancer and on strategies to reduce RCC were identified. The review was systematically conducted by searching the databases of MEDLINE, PUBMED Central, and Google Scholar libraries for original articles. From the search, we found that the incidence and mortality rates of RCC are strongly associated with four main risk factors, including family history (genetics), lifestyle (poor diet, cigarette smoking, excess alcohol drinking), environment (community where people live), and occupation (place where people work). In addition, unequal access to improvement in RCC cancer treatment, limited access to screening and diagnosis, and limited access to kidney transplant significantly contribute to the difference observed in survival rate between African Americans and Caucasians. There is also scientific evidence suggesting that some physicians contribute to racial disparities when performing kidney transplant among minority populations. New therapeutic measures should be taken to prevent or reduce RCC, especially among African Americans, the most vulnerable population group.


Subject(s)
Black or African American , Carcinoma, Renal Cell/ethnology , Carcinoma, Renal Cell/prevention & control , Health Status Disparities , Kidney Neoplasms/ethnology , Kidney Neoplasms/prevention & control , White People , Carcinoma, Renal Cell/mortality , Humans , Incidence , Kidney Neoplasms/mortality , Minority Groups , Prevalence , Risk Factors , United States/epidemiology
SELECTION OF CITATIONS
SEARCH DETAIL
...