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Non-benzodiazepine hypnotics ( "Z-drugs") are prescribed for insomnia, but might increase risk of motor vehicle crash (MVC) among older adults through prolonged drowsiness and delayed reaction times. We estimated the effect of initiating Z-drug treatment on the 12-week risk of MVC in a sequential target trial emulation. After linking New Jersey driver licensing and police-reported MVC data to Medicare claims, we emulated a new target trial each week (July 1, 2007 - October 7, 2017) in which Medicare fee-for-service beneficiaries were classified as Z-drug-treated or untreated at baseline and followed for an MVC. We used inverse probability of treatment and censoring weighted pooled logistic regression models to estimate risk ratios (RR) and risk differences with 95% bootstrap confidence limits (CLs). There were 257,554 person-trials, of which 103,371 were Z-drug-treated and 154,183 untreated, giving rise to 976 and 1,249 MVCs, respectively. The intention-to-treat RR was 1.06 (95%CLs 0.95, 1.16). For the per-protocol estimand, there were 800 MVCs and 1,241 MVCs among treated and untreated person-trials, respectively, suggesting a reduced MVC risk (RR 0.83 [95%CLs 0.74, 0.92]) with sustained Z-drug treatment. Z-drugs should be prescribed to older patients judiciously but not withheld entirely over concerns about MVC risk.
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Esters are valuable aroma compounds and can be produced enzymatically by Baeyer-Villiger monooxygenases (BVMOs) from (aliphatic) ketone precursors. However, a genetically encoded biosensor system for the assessment of BVMO activity and the detection of reaction products is missing. In this work, we assembled a synthetic enzyme cascade - featuring an esterase, an alcohol dehydrogenase, and LuxAB - in the heterologous host Escherichia coli. Target esters are produced by a BVMO, subsequently cleaved, and the corresponding alcohol oxidized through the artificial pathway. Ultimately, aldehyde products are detected in vivo by LuxAB, a luciferase from Photorhabdus luminescens that emits bioluminescence upon the oxidation of aldehydes to the corresponding carboxylates. This biosensor system greatly accelerated the screening and selection of active BVMO variants from a focused library, omitting commonly used low-throughput chromatographic analysis. Engineered enzymes accepted linear aliphatic ketones such as 2-undecanone and 2-dodecanone and exhibited improved ester formation.
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In the last decades, biocatalysis has offered new perspectives for the synthesis of (chiral) amines, which are essential building blocks for pharmaceuticals, fine and bulk chemicals. In this regard, amidases have been employed due to their broad substrate scope and their independence from expensive cofactors. To expand the repertoire of amidases, tools for their rapid identification and characterization are greatly demanded. In this work an ultra-high throughput growth selection assay based on the production of the folate precursor p-aminobenzoic acid (PABA) is introduced to identify amidase activity. PABA-derived amides structurally mimic the broad class of commonly used chromogenic substrates derived from p-nitroaniline. This suggests that the assay should be broadly applicable for the identification of amidases. Unlike conventional growth selection assays that rely on substrates as nitrogen or carbon source, our approach requires PABA in sub-nanomolar concentrations, making it exceptionally sensitive and ideal for engineering campaigns that aim at enhancing amidase activities from minimally active starting points, for example. The presented assay offers flexibility in the adjustment of sensitivity to suit project-specific needs using different expression systems and fine-tuning with the antimetabolite sulfathiazole. Application of this PABA-based assay facilitates the screening of millions of enzyme variants on a single agar plate within two days, without the need for laborious sample preparation or expensive instruments, with transformation efficiency being the only limiting factor. KEY POINTS: ⢠Ultra-high throughput assay (tens of millions on one agar plate) for amidase screening ⢠High sensitivity by coupling selection to folate instead of carbon or nitrogen source ⢠Highly adjustable in terms of sensitivity and expression of the engineering target.
Assuntos
Ácido 4-Aminobenzoico , Amidoidrolases , Ensaios de Triagem em Larga Escala , Amidoidrolases/metabolismo , Amidoidrolases/genética , Ensaios de Triagem em Larga Escala/métodos , Ácido 4-Aminobenzoico/metabolismo , Ácido 4-Aminobenzoico/química , Especificidade por Substrato , Escherichia coli/genética , Escherichia coli/enzimologia , Escherichia coli/metabolismoRESUMO
OBJECTIVE: To compare image quality and diagnostic performance of 3T and 7T magnetic resonance imaging (MRI) for direct depiction of finger flexor pulleys A2, A3 and A4 before and after artificial pulley rupture in an ex-vivo model using anatomic preparation as reference. MATERIALS AND METHODS: 30 fingers from 10 human cadavers were examined at 3T and 7T before and after being subjected to iatrogenic pulley rupture. MRI protocols were comparable in duration, both lasting less than 22 min. Two experienced radiologists evaluated the MRIs. Image quality was graded according to a 4-point Likert scale. Anatomic preparation was used as gold standard. RESULTS: In comparison, 7T versus 3T had a sensitivity and specificity for the detection of A2, A3 and A4 pulley lesions with 100% vs. 95%, respectively 98% vs. 100%. In the assessment of A3 pulley lesions sensitivity of 7T was superior to 3T MRI (100% vs. 83%), whereas specificity was lower (95% vs. 100%). Image quality assessed before and after iatrogenic rupture was comparable with 2.74 for 7T and 2.61 for 3T. Visualization of the A3 finger flexor pulley before rupture creation was significantly better for 7 T (p < 0.001). Interobserver variability showed substantial agreement at 3T (κ = 0.80) and almost perfect agreement at 7T (κ = 0.90). CONCLUSION: MRI at 3T allows a comparable diagnostic performance to 7T for direct visualization and characterization of finger flexor pulleys before and after rupture, with superiority of 7T MRI in the visualization of the normal A3 pulley.
Assuntos
Cadáver , Traumatismos dos Dedos , Imageamento por Ressonância Magnética , Sensibilidade e Especificidade , Traumatismos dos Tendões , Humanos , Imageamento por Ressonância Magnética/métodos , Ruptura/diagnóstico por imagem , Traumatismos dos Tendões/diagnóstico por imagem , Traumatismos dos Dedos/diagnóstico por imagem , Feminino , Masculino , Idoso , Idoso de 80 Anos ou maisRESUMO
Biocatalysis provides an attractive approach to facilitate synthetic reactions in aqueous media. Motivated by the discovery of promiscuous aminolysis activity of esterases, we exploited the esterase from Pyrobaculum calidifontis VA1 (PestE) for the synthesis of carbamates from different aliphatic, aromatic, and arylaliphatic amines and a set of carbonates such as dimethyl-, dibenzyl-, or diallyl carbonate. Thus, aniline and benzylamine derivatives, aliphatic and even secondary amines could be efficiently converted into the corresponding benzyloxycarbonyl (Cbz)- or allyloxycarbonyl (Alloc)-protected products in bulk water, with (isolated) yields of up to 99 %.
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Aciltransferases , Carbamatos , Esterases , Água , Esterases/metabolismo , Esterases/química , Carbamatos/química , Carbamatos/metabolismo , Carbamatos/síntese química , Água/química , Aciltransferases/metabolismo , Aciltransferases/química , Biocatálise , Estrutura Molecular , Aminas/química , Aminas/metabolismoRESUMO
While plastics like polyethylene terephthalate can already be degraded efficiently by the activity of hydrolases, other synthetic polymers like polyurethanes (PUs) and polyamides (PAs) largely resist biodegradation. In this study, we solved the first crystal structure of the metagenomic urethanase UMG-SP-1, identified highly flexible loop regions to comprise active site residues, and targeted a total of 20 potential hot spots by site-saturation mutagenesis. Engineering campaigns yielded variants with single mutations, exhibiting almost 3- and 8-fold improved activity against highly stable N-aryl urethane and amide bonds, respectively. Furthermore, we demonstrated the release of the corresponding monomers from a thermoplastic polyester-PU and a PA (nylonâ 6) by the activity of a single, metagenome-derived urethanase after short incubation times. Thereby, we expanded the hydrolysis profile of UMG-SP-1 beyond the reported low-molecular weight carbamates. Together, these findings promise advanced strategies for the bio-based degradation and recycling of plastic materials and waste, aiding efforts to establish a circular economy for synthetic polymers.
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Metagenoma , Hidrólise , Metagenômica , Glicosídeo Hidrolases/metabolismo , Glicosídeo Hidrolases/química , Glicosídeo Hidrolases/genética , Modelos Moleculares , Engenharia de ProteínasRESUMO
One of the central aims in Alzheimer's disease (AD) research is the identification of clinically relevant drug targets. A plethora of potential molecular targets work very well in preclinical model systems both in vitro and in vivo in AD mouse models. However, the lack of translation into clinical settings in the AD field is a challenging endeavor. Although it is long known that N-terminally truncated and pyroglutamate-modified Abeta (AßpE3) peptides are abundantly present in the brain of AD patients, form stable and soluble low-molecular weight oligomers, and induce neurodegeneration in AD mouse models, their potential as drug target has not been generally accepted in the past. This situation has dramatically changed with the report that passive immunization with donanemab, an AßpE3-specific antibody, cleared aymloid plaques and stabilized cognitive deficits in a group of patients with mild AD in a phase II trial. This review summarizes the current knowledge on the molecular mechanisms of generation of AßpE, its biochemical properties, and the intervention points as a drug target in AD.
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Doença de Alzheimer , Peptídeos beta-Amiloides , Animais , Modelos Animais de Doenças , Humanos , Camundongos , Placa Amiloide , Ácido Pirrolidonocarboxílico/químicaRESUMO
One of the hallmarks of Alzheimer's disease (AD) are deposits of amyloid-beta (Aß) protein in amyloid plaques in the brain. The Aß peptide exists in several forms, including full-length Aß1-42 and Aß1-40 - and the N-truncated species, pyroglutamate Aß3-42 and Aß4-42, which appear to play a major role in neurodegeneration. We previously identified a murine antibody (TAP01), which binds specifically to soluble, non-plaque N-truncated Aß species. By solving crystal structures for TAP01 family antibodies bound to pyroglutamate Aß3-14, we identified a novel pseudo ß-hairpin structure in the N-terminal region of Aß and show that this underpins its unique binding properties. We engineered a stabilised cyclic form of Aß1-14 (N-Truncated Amyloid Peptide AntibodieS; the 'TAPAS' vaccine) and showed that this adopts the same 3-dimensional conformation as the native sequence when bound to TAP01. Active immunisation of two mouse models of AD with the TAPAS vaccine led to a striking reduction in amyloid-plaque formation, a rescue of brain glucose metabolism, a stabilisation in neuron loss, and a rescue of memory deficiencies. Treating both models with the humanised version of the TAP01 antibody had similar positive effects. Here we report the discovery of a unique conformational epitope in the N-terminal region of Aß, which offers new routes for active and passive immunisation against AD.
Assuntos
Doença de Alzheimer , Vacinas , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Animais , Anticorpos/metabolismo , Encéfalo/metabolismo , Camundongos , Fragmentos de Peptídeos/metabolismo , Placa Amiloide/metabolismo , Ácido Pirrolidonocarboxílico/metabolismo , Vacinas/metabolismoRESUMO
OBJECTIVE: To examine prevalence of Alzheimer Disease and related dementias (ADRD) and patient characteristics as a function of comorbid insomnia and/or depression among heart failure (HF) patients discharged from hospitals. DESIGN: Retrospective cohort descriptive epidemiology study. SETTING: VA Hospitals. PARTICIPANTS: N = 373,897 Veterans hospitalized with heart failure from October 1, 2011 until September 30, 2020. MEASUREMENTS: We examined VA and Center for Medicare & Medicaid Services (CMS) coding in the year prior to admission using published ICD-9/10 codes for dementia, insomnia, and depression. The primary outcome was the prevalence of ADRD and the secondary outcomes were 30-day and 365-day mortality. RESULTS: The cohort were predominantly older adults (mean age = 72 years, SD = 11), male (97%), and White (73%). Dementia prevalence in participants without insomnia or depression was 12%. In those with both insomnia and depression, dementia prevalence was 34%. For insomnia alone and depression alone, dementia prevalence was 21% and 24%, respectively. Mortality followed a similar pattern with highest 30-day and 365-day mortality higher in those with both insomnia and depression. CONCLUSIONS: These results suggest that persons with both insomnia and depression are at an increased risk of ADRD and mortality compared to persons with one or neither condition. Screening for both insomnia and depression, especially in patients with other ADRD risk factors, could lead to earlier identification of ADRD. Understanding comorbid conditions which may represent earlier signs of ADRD may be critical in the identification of ADRD risk.
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Doença de Alzheimer , Insuficiência Cardíaca , Distúrbios do Início e da Manutenção do Sono , Veteranos , Humanos , Masculino , Idoso , Estados Unidos/epidemiologia , Doença de Alzheimer/complicações , Prevalência , Estudos Retrospectivos , Depressão/epidemiologia , Distúrbios do Início e da Manutenção do Sono/epidemiologia , Distúrbios do Início e da Manutenção do Sono/complicações , Medicare , Insuficiência Cardíaca/epidemiologia , Insuficiência Cardíaca/complicaçõesRESUMO
OBJECTIVE: We aimed to further improve knowledge about volar plate (VP) motion of the finger proximal interphalangeal joint (PIP), by analyzing the dynamic VP shape during a full range of finger flexion using magnetic resonance cinematography of the fingers (MRCF), and to compare the results with anatomical cross sections from cadaver specimens. MATERIALS AND METHODS: The dynamic sagittal VP shape was visualized with MRCF in a total number of 23 healthy volunteers. The length, angle, and thickness as well as the contact length of the VP to the PIP joint base were measured. Statistical analysis included t-test or rank-sum testing. Anatomical cross sections with differing degrees of PIP joint flexion were obtained from 12 cadaver specimens (fingers) for comparison. RESULTS: Significant positive correlations between PIP joint flexion angle and VP area, length, depth and the VP contact length were found. This matched histologically to fiber rearrangements especially within the loose third VP layer. CONCLUSION: Our study analyzed the full range of motion dynamic VP shape of the PIP joint using MRCF. This contributes to a more precise understanding of the complex interaction of the VP with the PIP joint and may facilitate evaluation of clinical cases such as VP avulsion or pulley rupture.
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Traumatismos dos Dedos , Articulações dos Dedos , Humanos , Articulações dos Dedos/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Dedos , Espectroscopia de Ressonância Magnética , Cadáver , Amplitude de Movimento ArticularRESUMO
Fatty aldehydes (FALs) can be derived from fatty acids (FAs) and related compounds and are frequently used as flavors and fragrances. Although chemical methods have been conventionally used, their selective biotechnological production aiming at more efficient and eco-friendly synthetic routes is in demand. α-Dioxygenases (α-DOXs) are heme-dependent oxidative enzymes biologically involved in the initial step of plant FA α-oxidation during which molecular oxygen is incorporated into the Cα -position of a FA (Cn ) to generate the intermediate FA hydroperoxide, which is subsequently converted into the shortened corresponding FAL (Cn-1 ). α-DOXs are promising biocatalysts for the flavor and fragrance industries, they do not require NAD(P)H as cofactors or redox partner proteins, and they have a broad substrate scope. Here, we highlight recent advances in the biocatalytic utilization of α-DOXs with emphasis on newly discovered cyanobacterial α-DOXs as well as analytical methods to measure α-DOX activity inâ vitro and inâ vivo.
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Dioxigenases , Dioxigenases/metabolismo , Odorantes , OxirreduçãoRESUMO
α-Dioxygenases (α-DOXs) are known as plant enzymes involved in the α-oxidation of fatty acids through which fatty aldehydes, with a high commercial value as flavor and fragrance compounds, are synthesized as products. Currently, little is known about α-DOXs from non-plant organisms. The phylogenic analysis reported here identified a substantial number of α-DOX enzymes across various taxa. Here, we report the functional characterization and Escherichia coli whole-cell application of two novel α-DOXs identified from cyanobacteria: CalDOX from Calothrix parietina and LepDOX from Leptolyngbya sp. The catalytic behavior of the recombinantly expressed CalDOX and LepDOX revealed that they are heme-dependent like plant α-DOXs but exhibit activities toward medium carbon fatty acids ranging from C10 to C14 unlike plant α-DOXs. The in-depth molecular investigation of cyanobacterial α-DOXs and their application in an E. coli whole system employed in this study is useful not only for the understanding of the molecular function of α-DOXs, but also for their industrial utilization in fatty aldehyde biosynthesis.Key points⢠Two novel α-dioxygenases from Cyanobacteria are reported⢠Both enzymes prefer medium-chain fatty acids⢠Both enzymes are useful for fatty aldehyde biosynthesis.
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Cianobactérias , Dioxigenases , Aldeídos , Escherichia coli/genética , Ácidos GraxosRESUMO
Biocatalysis has undergone revolutionary progress in the past century. Benefited by the integration of multidisciplinary technologies, natural enzymatic reactions are constantly being explored. Protein engineering gives birth to robust biocatalysts that are widely used in industrial production. These research achievements have gradually constructed a network containing natural enzymatic synthesis pathways and artificially designed enzymatic cascades. Nowadays, the development of artificial intelligence, automation, and ultra-high-throughput technology provides infinite possibilities for the discovery of novel enzymes, enzymatic mechanisms and enzymatic cascades, and gradually complements the lack of remaining key steps in the pathway design of enzymatic total synthesis. Therefore, the research of biocatalysis is gradually moving towards the era of novel technology integration, intelligent manufacturing and enzymatic total synthesis.
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Biocatálise , Animais , Inteligência Artificial , Vias Biossintéticas , Enzimas/metabolismo , Humanos , Engenharia de ProteínasRESUMO
The presynaptic protein Mover/TPRGL/SVAP30 is absent in Drosophila and C. elegans and differentially expressed in synapses in the rodent brain, suggesting that it confers specific functions to subtypes of presynaptic terminals. In order to investigate how the absence of this protein affects behavior and learning, Mover knockout mice (KO) were subjected to a series of established learning tests. To determine possible behavioral and cognitive alterations, male and female 8-week-old KO and C57Bl/6J wildtype (WT) control mice were tested in a battery of memory and anxiety tests. Testing included the cross maze, novel object recognition test (NOR), the Morris water maze (MWM), the elevated plus maze (EPM), and the open field test (OF). Mover KO mice showed impaired recognition memory in the NOR test, and decreased anxiety behavior in the OF and the EPM. Mover KO did not lead to changes in working memory in the cross maze or spatial reference memory in the MWM. However, a detailed analysis of the swimming strategies demonstrated allocentric-specific memory deficits in male KO mice. Our data indicate that Mover appears to control synaptic properties associated with specific forms of memory formation and behavior, suggesting that it has a modulatory role in synaptic transmission.
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Ansiedade , Caenorhabditis elegans , Animais , Comportamento Animal , Comportamento Exploratório , Feminino , Masculino , Aprendizagem em Labirinto , Transtornos da Memória , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Memória EspacialRESUMO
There has been much debate regarding the aetiology and pathogenesis of hallux valgus and it appears to be multifactorial with contracture or tightness of the Achilles tendon and more specifically the gastrocnemius being implicated as an intrinsic factor. The purpose of this study was to look at the association of gastrocnemius tightness, genu valgum and hallux valgus. A prospective case-control study with 25 patients in each group was carried out over a 12-month period. The case group observed adult patients who were referred primarily because of symptomatic hallux valgus and were assessed for the following: hallux valgus stage; presence or absence of isolated gastrocnemius tightness; presence or absence of genu valgum. The control group excluded those with pre-existing hallux valgus, genu valgum and rheumatoid arthritis and were assessed for isolated gastrocnemius tightness. There was a statistically significant association between the presence of genu valgum and hallux valgus when comparing both groups with a p < .001. There was also a statistically significant association between the Silfverskiöld test and the presence of hallux valgus, as well as the Silfverskiöld test and the presence of genu valgum with a p < .001. This study is the first to describe the association of gastrocnemius tightness, genu valgum and hallux valgus. Further studies are required to assess this relationship but knowledge and awareness of it can be applied by clinicians when considering the most appropriate management options with patients.
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Joanete , Geno Valgo , Hallux Valgus , Adulto , Estudos de Casos e Controles , Geno Valgo/diagnóstico por imagem , Geno Valgo/epidemiologia , Hallux Valgus/diagnóstico por imagem , Humanos , Estudos ProspectivosRESUMO
We engineered the cytochrome P450 monooxygenase CYP107D1 (OleP) from Streptomyces antibioticus for the stereo- and regioselective 7ß-hydroxylation of lithocholic acid (LCA) to yield ursodeoxycholic acid (UDCA). OleP was previously shown to hydroxylate testosterone at the 7ß-position but LCA is exclusively hydroxylated at the 6ß-position, forming murideoxycholic acid (MDCA). Structural and 3DM analysis, and molecular docking were used to identify amino acid residues F84, S240, and V291 as specificity-determining residues. Alanine scanning identified S240A as a UDCA-producing variant. A synthetic "small but smart" library based on these positions was screened using a colorimetric assay for UDCA. We identified a nearly perfectly regio- and stereoselective triple mutant (F84Q/S240A/V291G) that produces 10-fold higher levels of UDCA than the S240A variant. This biocatalyst opens up new possibilities for the environmentally friendly synthesis of UDCA from the biological waste product LCA.
Assuntos
Proteínas de Bactérias/metabolismo , Sistema Enzimático do Citocromo P-450/metabolismo , Ácido Ursodesoxicólico/metabolismo , Proteínas de Bactérias/genética , Sítios de Ligação , Domínio Catalítico , Sistema Enzimático do Citocromo P-450/genética , Ácido Desoxicólico/química , Ácido Desoxicólico/metabolismo , Hidroxilação , Ácido Litocólico/química , Ácido Litocólico/metabolismo , Simulação de Acoplamento Molecular , Mutagênese Sítio-Dirigida , Estereoisomerismo , Streptomyces/enzimologia , Ácido Ursodesoxicólico/síntese química , Ácido Ursodesoxicólico/químicaRESUMO
Pretibial panniculitis ossificans is a rare condition. In this report, we describe a 67-year-old male localized to his right pretibial tissue, approximately 20 years after contusion to the same area.
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Perna (Membro)/diagnóstico por imagem , Ossificação Heterotópica/diagnóstico por imagem , Idoso , Hallux Valgus/complicações , Humanos , Traumatismos da Perna/complicações , Masculino , Ossificação Heterotópica/etiologia , Ossificação Heterotópica/patologia , Ossificação Heterotópica/cirurgia , Paniculite , Doenças Raras , Tomografia Computadorizada por Raios XRESUMO
The molecular underpinnings associated with cognitive reserve remain poorly understood. Because animal models fail to fully recapitulate the complexity of human brain aging, postmortem studies from well-designed cohorts are crucial to unmask mechanisms conferring cognitive resistance against cumulative neuropathologies. We tested the hypothesis that functionality of the SNARE protein interactome might be an important resilience factor preserving cognitive abilities in old age. Cognition was assessed annually in participants from the Rush "Memory and Aging Project" (MAP), a community-dwelling cohort representative of the overall aging population. Associations between cognition and postmortem neurochemical data were evaluated in functional assays quantifying various species of the SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) machinery in samples from the inferior temporal (IT, nâ¯=â¯154) and middle-frontal (MF, nâ¯=â¯174) gyri. Using blue-native gel electrophoresis, we isolated and quantified several types of complexes containing the three SNARE proteins (syntaxin-1, SNAP25, VAMP), as well as the GABAergic/glutamatergic selectively expressed complexins-I/II (CPLX1/2), in brain tissue homogenates and reconstitution assays with recombinant proteins. Multivariate analyses revealed significant associations between IT and MF neurochemical data (SNARE proteins and/or complexes), and multiple age-related neuropathologies, as well as with multiple cognitive domains of MAP participants. Controlling for demographic variables, neuropathologic indices and total synapse density, we found that temporal 150-kDa SNARE species (representative of pan-synaptic functionality) and frontal CPLX1/CPLX2 ratio of 500-kDa heteromeric species (representative of inhibitory/excitatory input functionality) were, among all the immunocharacterized complexes, the strongest predictors of cognitive function nearest death. Interestingly, these two neurochemical variables were associated with different cognitive domains. In addition, linear mixed effect models of global cognitive decline estimated that both 150-kDa SNARE levels and CPLX1/CPLX2 ratio were associated with better cognition and less decline over time. The results are consistent with previous studies reporting that synapse dysfunction (i.e. dysplasticity) may be initiated early, and relatively independent of neuropathology-driven synapse loss. Frontotemporal dysregulation of the GABAergic/glutamatergic stimuli might be a target for future drug development.
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Envelhecimento/fisiologia , Disfunção Cognitiva/fisiopatologia , Lobo Frontal/fisiopatologia , Proteínas SNARE/fisiologia , Lobo Temporal/fisiopatologia , Idoso , Idoso de 80 Anos ou mais , Envelhecimento/genética , Envelhecimento/patologia , Disfunção Cognitiva/genética , Disfunção Cognitiva/patologia , Feminino , Lobo Frontal/patologia , Humanos , Masculino , Lobo Temporal/patologiaRESUMO
A synthetic cascade for the transformation of primary alcohols into polyhydroxylated compounds in Escherichia coli, through the in situ preparation of cytotoxic aldehyde intermediates and subsequent aldolase-mediated C-C bond formation, has been investigated. An enzymatic toolbox consisting of alcohol dehydrogenase AlkJ from Pseudomonas putida and the dihydroxyacetone-/hydroxyacetone-accepting aldolase variant Fsa1-A129S was applied. Pathway optimization was performed at the genetic and process levels. Three different arrangements of the alkJ and fsa1-A129S genes in operon, monocistronic, and pseudo-operon configuration were tested. The last of these proved to be most beneficial with regard to bacterial growth and protein expression levels. The optimized whole-cell catalyst, combined with a refined solid-phase extraction downstream purification protocol, provides diastereomerically pure carbohydrate derivatives that can be isolated in up to 91 % yield over two reaction steps.