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1.
Vascular ; : 17085381241236571, 2024 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-38404043

RESUMO

AIM: The aim of this study was to investigate the potential of novel automated machine learning (AutoML) in vascular medicine by developing a discriminative artificial intelligence (AI) model for the classification of anatomical patterns of peripheral artery disease (PAD). MATERIAL AND METHODS: Random open-source angiograms of lower limbs were collected using a web-indexed search. An experienced researcher in vascular medicine labelled the angiograms according to the most applicable grade of femoropopliteal disease in the Global Limb Anatomic Staging System (GLASS). An AutoML model was trained using the Vertex AI (Google Cloud) platform to classify the angiograms according to the GLASS grade with a multi-label algorithm. Following deployment, we conducted a test using 25 random angiograms (five from each GLASS grade). Model tuning through incremental training by introducing new angiograms was executed to the limit of the allocated quota following the initial evaluation to determine its effect on the software's performance. RESULTS: We collected 323 angiograms to create the AutoML model. Among these, 80 angiograms were labelled as grade 0 of femoropopliteal disease in GLASS, 114 as grade 1, 34 as grade 2, 25 as grade 3 and 70 as grade 4. After 4.5 h of training, the AI model was deployed. The AI self-assessed average precision was 0.77 (0 is minimal and 1 is maximal). During the testing phase, the AI model successfully determined the GLASS grade in 100% of the cases. The agreement with the researcher was almost perfect with the number of observed agreements being 22 (88%), Kappa = 0.85 (95% CI 0.69-1.0). The best results were achieved in predicting GLASS grade 0 and grade 4 (initial precision: 0.76 and 0.84). However, the AI model exhibited poorer results in classifying GLASS grade 3 (initial precision: 0.2) compared to other grades. Disagreements between the AI and the researcher were associated with the low resolution of the test images. Incremental training expanded the initial dataset by 23% to a total of 417 images, which improved the model's average precision by 11% to 0.86. CONCLUSION: After a brief training period with a limited dataset, AutoML has demonstrated its potential in identifying and classifying the anatomical patterns of PAD, operating unhindered by the factors that can affect human analysts, such as fatigue or lack of experience. This technology bears the potential to revolutionize outcome prediction and standardize evidence-based revascularization strategies for patients with PAD, leveraging its adaptability and ability to continuously improve with additional data. The pursuit of further research in AutoML within the field of vascular medicine is both promising and warranted. However, it necessitates additional financial support to realize its full potential.

3.
Int J Mol Sci ; 24(23)2023 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-38069170

RESUMO

In previous genome-wide association studies (GWAS), genetic loci associated with obesity and impaired fat distribution (FD) have been identified. In the present study, we elucidated the role of the PEMT gene, including the waist-hip-ratio-associated single nucleotide polymorphism rs4646404, and its influence on obesity-related metabolic traits. DNA from 2926 metabolically well-characterized subjects was used for genotyping. PEMT expression was analyzed in paired visceral (vis) and subcutaneous (sc) adipose tissue (AT) from a subset of 574 individuals. Additionally, PEMT expression was examined in vis, sc AT and liver tissue in a separate cohort of 64 patients with morbid obesity and liver disease. An in vitro Pemt knockdown was conducted in murine epididymal and inguinal adipocytes. Our findings highlight tissue-specific variations in PEMT mRNA expression across the three studied tissues. Specifically, vis PEMT mRNA levels correlated significantly with T2D and were implicated in the progression of non-alcoholic steatohepatitis (NASH), in contrast to liver tissue, where no significant associations were found. Moreover, sc PEMT expression showed significant correlations with several anthropometric- and metabolic-related parameters. The rs4646404 was associated with vis AT PEMT expression and also with diabetes-related traits. Our in vitro experiments supported the influence of PEMT on adipogenesis, emphasizing its role in AT biology. In summary, our data suggest that PEMT plays a role in regulating FD and has implications in metabolic diseases.


Assuntos
Estudo de Associação Genômica Ampla , Hepatopatia Gordurosa não Alcoólica , Humanos , Animais , Camundongos , Fosfatidiletanolamina N-Metiltransferase/genética , Fígado/metabolismo , Hepatopatia Gordurosa não Alcoólica/genética , Hepatopatia Gordurosa não Alcoólica/metabolismo , RNA Mensageiro/metabolismo , Obesidade/genética , Obesidade/metabolismo
4.
Respirol Case Rep ; 11(11): e01231, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37840600

RESUMO

Here we describe three cases of sarcoidosis which were diagnosed following COVID infection. Treating clinicians should consider post-COVID-19 sarcoidosis in their differential, as it represents a potentially treatable cause of persistent symptomatology.

5.
Am J Respir Crit Care Med ; 208(9): 975-982, 2023 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-37672028

RESUMO

Rationale: Identifying patients with pulmonary fibrosis (PF) at risk of progression can guide management. Objectives: To explore the utility of combining baseline BAL and computed tomography (CT) in differentiating progressive and nonprogressive PF. Methods: The derivation cohort consisted of incident cases of PF for which BAL was performed as part of a diagnostic workup. A validation cohort was prospectively recruited with identical inclusion criteria. Baseline thoracic CT scans were scored for the extent of fibrosis and usual interstitial pneumonia (UIP) pattern. The BAL lymphocyte proportion was recorded. Annualized FVC decrease of >10% or death within 1 year was used to define disease progression. Multivariable logistic regression identified the determinants of the outcome. The optimum binary thresholds (maximal Wilcoxon rank statistic) at which the extent of fibrosis on CT and the BAL lymphocyte proportion could distinguish disease progression were identified. Measurements and Main Results: BAL lymphocyte proportion, UIP pattern, and fibrosis extent were significantly and independently associated with disease progression in the derivation cohort (n = 240). Binary thresholds for increased BAL lymphocyte proportion and extensive fibrosis were identified as 25% and 20%, respectively. An increased BAL lymphocyte proportion was rare in patients with a UIP pattern (8 of 135; 5.9%) or with extensive fibrosis (7 of 144; 4.9%). In the validation cohort (n = 290), an increased BAL lymphocyte proportion was associated with a significantly lower probability of disease progression in patients with nonextensive fibrosis or a non-UIP pattern. Conclusions: BAL lymphocytosis is rare in patients with extensive fibrosis or a UIP pattern on CT. In patients without a UIP pattern or with limited fibrosis, a BAL lymphocyte proportion of ⩾25% was associated with a lower likelihood of progression.


Assuntos
Fibrose Pulmonar Idiopática , Doenças Pulmonares Intersticiais , Humanos , Doenças Pulmonares Intersticiais/diagnóstico por imagem , Progressão da Doença , Tomografia Computadorizada por Raios X/métodos , Tomografia , Pulmão/diagnóstico por imagem , Estudos Retrospectivos
6.
Ann Am Thorac Soc ; 20(9): 1267-1273, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37159951

RESUMO

Rationale: Cough is a commonly reported symptom in idiopathic pulmonary fibrosis (IPF) that negatively impacts patient-reported quality of life (QoL). However, both the burden of cough at diagnosis and the behavior of cough over time have not been systematically described in patients with IPF. Objectives: By utilizing data prospectively collected as part of the PROFILE study, we sought to assess cough burden and the impact that this has on QoL within a cohort of patients with newly diagnosed IPF. We also reexamined the previously described relationship between cough and mortality and the association of cough with the MUC5B promoter polymorphism. Methods: The PROFILE study is a multicenter, prospective, observational, longitudinal cohort study of incident IPF. Scores on the Leicester Cough Questionnaire (LCQ) were recorded at baseline in 632 subjects and then repeated 6 monthly in a subset (n = 216) of the cohort. Results: The median LCQ score at diagnosis was 16.1 (interquartile range, 6.5). LCQ scores remained stable over the subsequent year in the majority of patients. There was a weak association between LCQ score and baseline lung function, with worse cough-related QoL associated with more severe physiological impairment. Cough scores were not associated with subsequent mortality after correcting for baseline lung function. Furthermore, there was no relationship between LCQ score and MUC5B promoter polymorphism status. Conclusions: The burden of cough in IPF is high. Although cough is weakly associated with disease severity at baseline, cough-specific QoL, as measured by the LCQ, confers no prognostic value. Cough-specific QoL burden remains relatively stable over time and does not associate with MUC5B promoter polymorphism.


Assuntos
Tosse , Fibrose Pulmonar Idiopática , Humanos , Tosse/epidemiologia , Tosse/etiologia , Tosse/diagnóstico , Qualidade de Vida , Estudos Longitudinais , Estudos Prospectivos , Fibrose Pulmonar Idiopática/complicações , Inquéritos e Questionários
7.
Lancet Respir Med ; 11(8): 709-725, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37216955

RESUMO

Although the exact prevalence of post-COVID-19 condition (also known as long COVID) is unknown, more than a third of patients with COVID-19 develop symptoms that persist for more than 3 months after SARS-CoV-2 infection. These sequelae are highly heterogeneous in nature and adversely affect multiple biological systems, although breathlessness is a frequently cited symptom. Specific pulmonary sequelae, including pulmonary fibrosis and thromboembolic disease, need careful assessment and might require particular investigations and treatments. COVID-19 outcomes in people with pre-existing respiratory conditions vary according to the nature and severity of the respiratory disease and how well it is controlled. Extrapulmonary complications such as reduced exercise tolerance and frailty might contribute to breathlessness in post-COVID-19 condition. Non-pharmacological therapeutic options, including adapted pulmonary rehabilitation programmes and physiotherapy techniques for breathing management, might help to attenuate breathlessness in people with post-COVID-19 condition. Further research is needed to understand the origins and course of respiratory symptoms and to develop effective therapeutic and rehabilitative strategies.


Assuntos
COVID-19 , Fibrose Pulmonar , Humanos , Síndrome de COVID-19 Pós-Aguda , COVID-19/complicações , SARS-CoV-2 , Dispneia/etiologia , Dispneia/terapia , Progressão da Doença
8.
Respirology ; 28(7): 627-635, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37121779

RESUMO

Novel genetic associations for idiopathic pulmonary fibrosis (IPF) risk have been identified. Common genetic variants associated with IPF are also associated with chronic hypersensitivity pneumonitis. The characterization of underlying mechanisms, such as pathways involved in myofibroblast differentiation, may reveal targets for future treatments. Newly identified circulating biomarkers are associated with disease progression and mortality. Deep learning and machine learning may increase accuracy in the interpretation of CT scans. Novel treatments have shown benefit in phase 2 clinical trials. Hospitalization with COVID-19 is associated with residual lung abnormalities in a substantial number of patients. Inequalities exist in delivering and accessing interstitial lung disease specialist care.


Assuntos
Alveolite Alérgica Extrínseca , COVID-19 , Fibrose Pulmonar Idiopática , Doenças Pulmonares Intersticiais , Humanos , Doenças Pulmonares Intersticiais/diagnóstico , Fibrose Pulmonar Idiopática/diagnóstico , Fibrose Pulmonar Idiopática/genética , Fibrose Pulmonar Idiopática/terapia , Progressão da Doença , Pulmão/diagnóstico por imagem
9.
J Vet Diagn Invest ; 35(3): 304-306, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36929829

RESUMO

Although the novel Brazilian porcupinepox virus (BPoPV) can infect wild porcupines, its lethality and zoonotic potential are not well-established. In May 2021, a free-ranging neotropical porcupine (Coendou longicaudatus boliviensis) rescued from the natural savanna in the Brazilian Cerrado, Mato Grosso State, was presented with a lethal poxviral infection. Clinical signs and PCR detection of BPoPV supported the diagnosis. Poxviral lesions included erythema, exfoliative dermatitis, and erosions involving mainly the face, hindlimb, and vulva. Histologically, the lesions consisted of proliferative and necrotic dermatitis, intraepidermal and follicular pustules, and intracytoplasmic inclusion bodies in keratinocytes. Phylogenetic analysis revealed BPoPV strains closely related to other rodent-infecting poxviruses. This poxviral infection resulted in the death of a specimen of C. l. boliviensis; the effect on species conservation, and the potential of spillover into humans and other vertebrates remain unknown.


Assuntos
Viroses , Humanos , Feminino , Animais , Brasil/epidemiologia , Filogenia , Reação em Cadeia da Polimerase/veterinária , Viroses/veterinária
10.
Respir Res ; 24(1): 51, 2023 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-36788603

RESUMO

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a chronic lung disease that affects 3 million people worldwide. Senescence and small extracellular vesicles (sEVs) have been implicated in the pathogenesis of IPF, although how sEVs promote disease remains unclear. Here, we profile sEVs from bronchial epithelial cells and determine small RNA (smRNA) content. METHODS: Conditioned media was collected and sEVs were isolated from normal human bronchial epithelial cells (NHBEs) and IPF-diseased human bronchial epithelial cells (DHBEs). RESULTS: Increased sEV release from DHBEs compared to NHBEs (n = 4; p < 0.05) was detected by nanoparticle tracking analysis. NHBEs co-cultured with DHBE-derived sEVs for 72 h expressed higher levels of SA-ß-Gal and γH2AX protein, p16 and p21 RNA and increased secretion of IL6 and IL8 proteins (all n = 6-8; p < 0.05). sEVs were also co-cultured with healthy air-liquid interface (ALI) cultures and similar results were observed, with increases in p21 and p16 gene expression and IL6 and IL8 (basal and apical) secretion (n = 6; p < 0.05). Transepithelial electrical resistance (TEER) measurements, a reflection of epithelial barrier integrity, were decreased upon the addition of DHBE-derived sEVs (n = 6; p < 0.05). smRNA-sequencing identified nineteen significantly differentially expressed miRNA in DHBE-derived sEVs compared to NHBE-derived sEVs, with candidate miRNAs validated by qPCR (all n = 5; p < 0.05). Four of these miRNAs were upregulated in NHBEs co-cultured with DHBE-derived sEVs and three in healthy ALI cultures co-cultured with DHBE-derived sEVs (n = 3-4; p < 0.05). CONCLUSIONS: This data demonstrates that DHBE-derived sEVs transfer senescence to neighbouring healthy cells, promoting the disease state in IPF.


Assuntos
Vesículas Extracelulares , Fibrose Pulmonar Idiopática , MicroRNAs , Humanos , Interleucina-6/metabolismo , Interleucina-8/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , Fibrose Pulmonar Idiopática/metabolismo , Vesículas Extracelulares/metabolismo
11.
Biochemistry ; 62(2): 410-418, 2023 01 17.
Artigo em Inglês | MEDLINE | ID: mdl-34762799

RESUMO

The DNA polymerase I from Geobacillus stearothermophilus (also known as Bst DNAP) is widely used in isothermal amplification reactions, where its strand displacement ability is prized. More robust versions of this enzyme should be enabled for diagnostic applications, especially for carrying out higher temperature reactions that might proceed more quickly. To this end, we appended a short fusion domain from the actin-binding protein villin that improved both stability and purification of the enzyme. In parallel, we have developed a machine learning algorithm that assesses the relative fit of individual amino acids to their chemical microenvironments at any position in a protein and applied this algorithm to predict sequence substitutions in Bst DNAP. The top predicted variants had greatly improved thermotolerance (heating prior to assay), and upon combination, the mutations showed additive thermostability, with denaturation temperatures up to 2.5 °C higher than the parental enzyme. The increased thermostability of the enzyme allowed faster loop-mediated isothermal amplification assays to be carried out at 73 °C, where both Bst DNAP and its improved commercial counterpart Bst 2.0 are inactivated. Overall, this is one of the first examples of the application of machine learning approaches to the thermostabilization of an enzyme.


Assuntos
DNA Polimerase Dirigida por DNA , Técnicas de Amplificação de Ácido Nucleico , DNA Polimerase Dirigida por DNA/genética , DNA Polimerase Dirigida por DNA/metabolismo , DNA Polimerase I/química , Geobacillus stearothermophilus
12.
Biosens Bioelectron ; 222: 114993, 2023 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-36525710

RESUMO

The organized self-assembly of conductive biological structures holds promise for creating new bioelectronic devices. In particular, Geobacter sulfurreducens type IVa pili have proven to be a versatile material for fabricating protein nanowire-based devices. To scale the production of conductive pili, we designed a strain of Shewanella oneidensis that heterologously expressed abundant, conductive Geobacter pili when grown aerobically in liquid culture. S. oneidensis expressing a cysteine-modified pilin, designed to enhance the capability to bind to gold, generated conductive pili that self-assembled into biohybrid filaments in the presence of gold nanoparticles. Elemental composition analysis confirmed the filament-metal interactions within the structures, which were several orders of magnitude larger than previously described metal:organic filaments. The results demonstrate that the S. oneidensis chassis significantly advances the possibilities for facile conductive protein nanowire design and fabrication.


Assuntos
Técnicas Biossensoriais , Geobacter , Nanopartículas Metálicas , Ouro , Fímbrias Bacterianas/metabolismo , Transporte de Elétrons
13.
Proc Natl Acad Sci U S A ; 119(3)2022 01 18.
Artigo em Inglês | MEDLINE | ID: mdl-35042777

RESUMO

Mitochondrial ribosomes (mitoribosomes) play a central role in synthesizing mitochondrial inner membrane proteins responsible for oxidative phosphorylation. Although mitoribosomes from different organisms exhibit considerable structural variations, recent insights into mitoribosome assembly suggest that mitoribosome maturation follows common principles and involves a number of conserved assembly factors. To investigate the steps involved in the assembly of the mitoribosomal small subunit (mt-SSU) we determined the cryoelectron microscopy structures of middle and late assembly intermediates of the Trypanosoma brucei mitochondrial small subunit (mt-SSU) at 3.6- and 3.7-Å resolution, respectively. We identified five additional assembly factors that together with the mitochondrial initiation factor 2 (mt-IF-2) specifically interact with functionally important regions of the rRNA, including the decoding center, thereby preventing premature mRNA or large subunit binding. Structural comparison of assembly intermediates with mature mt-SSU combined with RNAi experiments suggests a noncanonical role of mt-IF-2 and a stepwise assembly process, where modular exchange of ribosomal proteins and assembly factors together with mt-IF-2 ensure proper 9S rRNA folding and protein maturation during the final steps of assembly.


Assuntos
Proteínas Mitocondriais/química , Ribossomos Mitocondriais/química , Fosforilação Oxidativa , RNA Ribossômico/química , Proteínas Ribossômicas/química , Subunidades Ribossômicas/química , Linhagem Celular , Microscopia Crioeletrônica , Mitocôndrias/metabolismo , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Ribossomos Mitocondriais/metabolismo , Modelos Moleculares , RNA Ribossômico/genética , RNA Ribossômico/metabolismo , Proteínas Ribossômicas/genética , Proteínas Ribossômicas/metabolismo , Subunidades Ribossômicas/genética , Subunidades Ribossômicas/metabolismo , Trypanosoma brucei brucei/genética , Trypanosoma brucei brucei/metabolismo
14.
Appl Environ Microbiol ; 88(1): e0162221, 2022 01 11.
Artigo em Inglês | MEDLINE | ID: mdl-34669448

RESUMO

The multi-heme c-type cytochrome OmcS is one of the central components used for extracellular electron transport in the Geobacter sulfurreducens strain DL-1, but its role in other microbes, including other strains of G. sulfurreducens, is currently a matter of debate. Therefore, we investigated the function of OmcS in the G. sulfurreducens strain KN400, which is even more effective in extracellular electron transfer than the DL-1 strain. We found that deleting omcS from strain KN400 did not negatively impact the rate of Fe(III) oxide reduction and that the cells expressed conductive filaments. Replacing the wild-type pilin gene with the aro-5 pilin gene eliminated the OmcS-deficient strain's ability to transport electrons to insoluble electron acceptors and diminished filament conductivity. These results are consistent with the concept that electrically conductive pili are the primary conduit for long-range electron transfer in G. sulfurreducens and closely related species. These findings, coupled with the lack of OmcS homologs in other microbes capable of extracellular electron transfer, suggest that OmcS is not a common critical component for extracellular electron transfer. IMPORTANCE OmcS has been widely studied and noted to be one of the key components for extracellular electron exchange by the Geobacter sulfurreducens strain DL-1. However, the true importance of OmcS warrants further investigation because it is well known that few bacteria, even within the Geobacteraceae family, contain OmcS homologs, and many bacteria that are capable of extracellular electron transfer lack an abundance of any type of outer surface c-type cytochrome. In addition, there is debate about the importance of OmcS filaments in the mechanism of extracellular electron transport to insoluble electron acceptors by G. sulfurreducens. It has been suggested that filaments comprised of OmcS rather than e-pili are the predominant conductive filaments expressed by G. sulfurreducens. However, the results presented here, along with multiple other sources of evidence, indicate that OmcS filaments cannot be the primary, conductive, protein nanowires expressed by G. sulfurreducens.


Assuntos
Elétrons , Geobacter , Citocromos/metabolismo , Transporte de Elétrons , Compostos Férricos/metabolismo , Fímbrias Bacterianas/genética , Fímbrias Bacterianas/metabolismo , Geobacter/genética , Geobacter/metabolismo , Oxirredução
15.
Exp Clin Endocrinol Diabetes ; 130(7): 454-461, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34284506

RESUMO

AIMS: To collect and analyse representative data of structural and process quality in the management of diabetic emergencies in Germany in 2020. METHODS: A standardised questionnaire comprising detailed items concerning clinically relevant parameters on the structural and process quality of out-of-hospital management of diabetic emergencies was sent nationwide to medical directors of emergency medical service districts (EMSDs). Results were compared with those from a similar study conducted in 2001. RESULTS: The return rate of the questionnaires represented 126 EMSDs, serving a total population of > 40.1 million. Only 4% of ambulances carried glucagon (6% in 2001). In 2020, blood glucose determination increased significantly to 71% of all emergency interventions and to 29% of suspected cardiac emergencies (24% and 15%, respectively, in 2001). In 100% of EMSDs severe hypoglycaemia (SH) was treated by paramedics by administering intravenous dextrose before the arrival of a doctor compared to 63% in 2001. The potential value of nasal glucagon was acknowledged by 43% of responders. In selected patients, treatment of SH was conducted without hospital admission in 78% of EMDs (60% in 2001). Fifty-three percent of medical directors acknowledged the need for further training in diabetic emergencies (47% in 2001). Cooperation for medical education between emergency teams and a diabetes centre was reported by 14% (41% in 2001). CONCLUSION: Structural and process quality of the management of diabetic emergencies in Germany has improved considerably since 2001. Persisting deficiencies could be improved by providing better medical equipment in ambulances and ongoing education to the entire emergency teams.


Assuntos
Diabetes Mellitus , Hipoglicemia , Diabetes Mellitus/terapia , Emergências , Alemanha/epidemiologia , Glucagon , Hospitais , Humanos , Hipoglicemia/terapia
17.
mBio ; 12(4): e0220921, 2021 08 31.
Artigo em Inglês | MEDLINE | ID: mdl-34465020

RESUMO

Geobacter sulfurreducens is a model microbe for elucidating the mechanisms for extracellular electron transfer in several biogeochemical cycles, bioelectrochemical applications, and microbial metal corrosion. Multiple lines of evidence previously suggested that electrically conductive pili (e-pili) are an essential conduit for long-range extracellular electron transport in G. sulfurreducens. However, it has recently been reported that G. sulfurreducens does not express e-pili and that filaments comprised of multi-heme c-type cytochromes are responsible for long-range electron transport. This possibility was directly investigated by examining cells, rather than filament preparations, with atomic force microscopy. Approximately 90% of the filaments emanating from wild-type cells had a diameter (3 nm) and conductance consistent with previous reports of e-pili harvested from G. sulfurreducens or heterologously expressed in Escherichia coli from the G. sulfurreducens pilin gene. The remaining 10% of filaments had a morphology consistent with filaments comprised of the c-type cytochrome OmcS. A strain expressing a modified pilin gene designed to yield poorly conductive pili expressed 90% filaments with a 3-nm diameter, but greatly reduced conductance, further indicating that the 3-nm diameter conductive filaments in the wild-type strain were e-pili. A strain in which genes for five of the most abundant outer-surface c-type cytochromes, including OmcS, were deleted yielded only 3-nm-diameter filaments with the same conductance as in the wild type. These results demonstrate that e-pili are the most abundant conductive filaments expressed by G. sulfurreducens, consistent with previous functional studies demonstrating the need for e-pili for long-range extracellular electron transfer. IMPORTANCE Electroactive microbes have significant environmental impacts, as well as applications in bioenergy and bioremediation. The composition, function, and even existence of electrically conductive pili (e-pili) has been one of the most contentious areas of investigation in electromicrobiology, in part because e-pili offer a mechanism for long-range electron transport that does not involve the metal cofactors common in much of biological electron transport. This study demonstrates that e-pili are abundant filaments emanating from Geobacter sulfurreducens, which serves as a model for long-range extracellular electron transfer in direct interspecies electron transfer, dissimilatory metal reduction, microbe-electrode exchange, and corrosion caused by direct electron uptake from Fe(0). The methods described in this study provide a simple strategy for evaluating the distribution of conductive filaments throughout the microbial world with an approach that avoids artifactual production and/or enrichment of filaments that may not be physiologically relevant.


Assuntos
Condutividade Elétrica , Proteínas de Fímbrias/genética , Fímbrias Bacterianas/metabolismo , Geobacter/metabolismo , Microscopia de Força Atômica/métodos , Elétrons , Escherichia coli/genética , Geobacter/citologia , Oxirredução
18.
Microbiol Spectr ; 9(2): e0087721, 2021 10 31.
Artigo em Inglês | MEDLINE | ID: mdl-34585977

RESUMO

Geobacter sulfurreducens is commonly employed as a model for the study of extracellular electron transport mechanisms in the Geobacter species. Deletion of pilB, which is known to encode the pilus assembly motor protein for type IV pili in other bacteria, has been proposed as an effective strategy for evaluating the role of electrically conductive pili (e-pili) in G. sulfurreducens extracellular electron transfer. In those studies, the inhibition of e-pili expression associated with pilB deletion was not demonstrated directly but was inferred from the observation that pilB deletion mutants produced lower current densities than wild-type cells. Here, we report that deleting pilB did not diminish current production. Conducting probe atomic force microscopy revealed filaments with the same diameter and similar current-voltage response as e-pili harvested from wild-type G. sulfurreducens or when e-pili are expressed heterologously from the G. sulfurreducens pilin gene in Escherichia coli. Immunogold labeling demonstrated that a G. sulfurreducens strain expressing a pilin monomer with a His tag continued to express His tag-labeled filaments when pilB was deleted. These results suggest that a reinterpretation of the results of previous studies on G. sulfurreducens pilB deletion strains may be necessary. IMPORTANCE Geobacter sulfurreducens is a model microbe for the study of biogeochemically and technologically significant processes, such as the reduction of Fe(III) oxides in soils and sediments, bioelectrochemical applications that produce electric current from waste organic matter or drive useful processes with the consumption of renewable electricity, direct interspecies electron transfer in anaerobic digestors and methanogenic soils and sediments, and metal corrosion. Elucidating the phenotypes associated with gene deletions is an important strategy for determining the mechanisms for extracellular electron transfer in G. sulfurreducens. The results reported here demonstrate that we cannot replicate the key phenotype reported for a gene deletion that has been central to the development of models for long-range electron transport in G. sulfurreducens.


Assuntos
Proteínas de Bactérias/genética , Condutividade Elétrica , Transporte de Elétrons/fisiologia , Proteínas de Fímbrias/genética , Fímbrias Bacterianas/metabolismo , Geobacter/metabolismo , Oxirredutases/genética , Transporte de Elétrons/genética , Fímbrias Bacterianas/genética , Deleção de Genes , Geobacter/genética , Sedimentos Geológicos/microbiologia , Microscopia de Força Atômica
19.
J Clin Psychopharmacol ; 41(5): 534-539, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34519455

RESUMO

BACKGROUND: Sedation is a common and incapacitating clozapine adverse effect, but the factors associated with sedation and its pharmacological management remain poorly studied. METHODS: We conducted a retrospective cohort study based on deidentified electronic clinical records of clozapine-treated patients from the secondary mental health care provider for Cambridgeshire and Peterborough, United Kingdom. We first evaluated cross-sectionally the influence of clozapine dose, clozapine, and norclozapine plasma levels on self-reported hours slept, as a proxy for sedation, using bivariate correlation and then the longitudinal effect of changes in clozapine dose and other 23 medications using linear mixed effect models. We followed 241 clozapine-treated patients for 56 months on average, with 2237 face-to-face assessments in total. RESULTS: Patients slept for a mean of 9.35 h/d, with 46% reporting 10 h/d or more. Cross-sectionally, sleep duration did not correlate with clozapine dose (r = 0.14, P = 0.106), but with clozapine plasma levels (r = 0.38, P < 0.0001) and norclozapine plasma levels (r = 0.25, P = 0.005). Longitudinally, the final mixed-effects model revealed 4 pharmacological variables that had a significant impact on hours slept: clozapine, risperidone augmentation, and atenolol were associated with increased sleep, whereas aripiprazole augmentation was associated with decreased sleep. We found that 20 other psychotropic medications measured were not associated with changes in sleep when added to clozapine. Excess sleep is a clozapine level-dependent adverse effect. CONCLUSIONS: The impact of different augmentation strategies might help clinicians decide on the most adequate strategy, albeit further studies should confirm our results.


Assuntos
Clozapina/efeitos adversos , Clozapina/farmacologia , Sono/efeitos dos fármacos , Adulto , Antipsicóticos/efeitos adversos , Antipsicóticos/farmacologia , Interações Medicamentosas , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Autorrelato , Fatores de Tempo , Reino Unido
20.
Preprint em Inglês | bioRxiv | ID: ppbiorxiv-439918

RESUMO

DNA polymerase from Geobacillus stearothermophilus, Bst DNA polymerase (Bst DNAP), is a versatile enzyme with robust strand-displacing activity that enables loop-mediated isothermal amplification (LAMP). Despite its exclusive usage in LAMP assay, its properties remain open to improvement. Here, we describe logical redesign of Bst DNAP by using multimodal application of several independent and orthogonal rational engineering methods such as domain addition, supercharging, and machine learning predictions of amino acid substitutions. The resulting Br512g3 enzyme is not only thermostable and extremely robust but it also displays improved reverse transcription activity and the ability to carry out ultrafast LAMP at 74 {degrees}C. Our study illustrates a new enzyme engineering strategy as well as contributes a novel engineered strand displacing DNA polymerase of high value to diagnostics and other fields.

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