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Background: We tested the hypothesis that non-invasive pulse wave analysis (PWA)-derived systemic circulation variables can predict invasive hemodynamics of pulmonary circulation and the indicator of right heart function, N-terminal pro-brain natriuretic peptide (NT-proBNP), in patients with precapillary pulmonary hypertension (PH). Methods: This prospective study enrolled patients with group 1 and 4 PH who had complete PWA, NT-proBNP, and hemodynamics data. Risk assessment-based "hemodynamic score (HS)" and principal component analysis-based PWA variable grouping were determined/performed. Models of hierarchical multiple linear regression (HMLR) and receiver operating characteristic (ROC) curves were used to determine the relationships of PWA variables with HS and NT-proBNP and to predict the latter parameters. Results: Fifty-three PWAs were included. PWA variables were classified into 4 eigenvalue principal components (representing 90% configuration). Univariate analysis showed that left ventricular ejection time (LVET) was significantly negatively associated with HS and NT-proBNP levels. HMLR analysis showed that LVET was still significantly, negatively, and independently associated with HS (B = -0.006 [-0.010~-0.001]) and NT-proBNP (B = -13.47 [-21.20~-5.73]). ROC curve analysis showed that LVET > 306.9 msec and > 313.2 msec predicted the low-risk group of HS (AUC: 0.802; p = 0.001; sensitivity: 100%; and specificity: 59%) and low-to-intermediate risk levels of NT-proBNP (AUC: 0.831; p < 0.001; sensitivity: 100%; and specificity: 59%). Conclusions: The non-invasive PWA parameter, LVET, is an independent predictor of invasive right heart HS and NT-proBNP levels; it may serve as a novel biomarker of right ventricular function in patients with pre-capillary PH.
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Sweating during exercise is regulated by objective parameters, body weight, and endothelial function, among other factors. However, the relationship between vascular arterial stiffness and sweat volume in young adults remains unclear. This study aimed to identify hemodynamic parameters before exercise that can predict sweat volume during exercise, and post-exercise parameters that can be predicted by the sweat volume. Eighty-nine young healthy subjects (aged 21.9 ± 1.7 years, 51 males) were recruited to each perform a 3-km run on a treadmill. Demographic and anthropometric data were collected and hemodynamic data were obtained, including heart rate, blood pressure and pulse wave analysis using non-invasive tonometry. Sweat volume was defined as pre-exercise body weight minus post-exercise body weight. Post-exercise hemodynamic parameters were also collected. Sweat volume was significantly associated with gender, body surface area (BSA) (b = 0.288, p = 0.010), peripheral systolic blood pressure (SBP), peripheral and central pulse pressure (PP), and was inversely associated with augmentation index at an HR of 75 beats/min (AIx@HR75) (b = -0.005, p = 0.019) and ejection duration. While BSA appeared to predict central PP (B = 19.271, p ≤ 0.001), central PP plus AIx@HR75 further predicted sweat volume (B = 0.008, p = 0.025; B = -0.009, p = 0.003 respectively). Sweat volume was associated with peripheral SBP change (B = -17.560, p = 0.031). Sweat volume during a 3-km run appears to be influenced by hemodynamic parameters, including vascular arterial stiffness and central pulse pressure. Results of the present study suggest that vascular arterial stiffness likely regulates sweat volume during exercise.
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Hemodinâmica , Corrida/fisiologia , Sudorese/fisiologia , Pressão Sanguínea , Superfície Corporal , Feminino , Frequência Cardíaca , Humanos , Masculino , Estudos Prospectivos , Fatores Sexuais , Volume Sistólico , Suor , Rigidez Vascular , Adulto JovemRESUMO
Mental health literacy (MHL) predicts help-seeking attitudes. However, the relationship between components of MHL and help-seeking attitudes has not been thoroughly examined. This study aims to examine whether mental illness stigma, help-seeking efficacy, and maintenance of positive mental health mediated the relationship between recognition of mental disorders and help-seeking attitudes, using a meta-analytic structural equation modeling (MASEM) approach. A comprehensive literature search was conducted to gather relevant studies (111 articles with 118 independent samples), and their data (k = 185) were analyzed using MASEM. Reducing mental illness stigma or increasing help-seeking efficacy may be effective strategies for promoting help-seeking behaviors among individuals who recognize mental disorders, while the maintenance of positive mental health did not significantly mediate the relationship between recognition of mental disorders and help-seeking attitudes. These findings suggest that reducing stigma or increasing help-seeking efficacy may be an effective strategy for promoting help-seeking behaviors among individuals who can identify mental disorders. The use of MASEM in this study highlights the importance of integrating multiple studies to understand the complex relationship between MHL components and help-seeking attitudes. (PsycInfo Database Record (c) 2024 APA, all rights reserved).
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Letramento em Saúde , Transtornos Mentais , Humanos , Saúde Mental , Transtornos Mentais/terapia , Transtornos Mentais/psicologia , Estigma SocialRESUMO
Adult haemophagocytic lymphohistiocytosis (HLH) is an infrequent and life-threatening condition. The most common triggers of HLH are malignancy and virus, and bacterial infections are rarely implicated. We present a case of HLH secondary to Staphylococcus aureus infection and systemically searched the PubMed database for publications on HLH associated with Staphylococcus aureus infection and reviewed nine cases from seven studies. A marked third of patients had infective endocarditis, while the mortality rate was 44 %. HLH developed in our case despite elimination of MRSA from the bloodstream, leading to eventual demise of our patient, suggesting that prolonged hyperimmune response may persist even after the elimination of initial triggering factor. Our case highlights the necessity of high clinical suspicion and prompt diagnosis of HLH.
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Transdermal nicotine patches (TNPs), administering nicotine into the bloodstream through skin, have been widely used as nicotine replacement therapy, and exposure to nicotine can be detected by measurement of plasma cotinine concentration. In animal studies, nicotine treatment could increase the number of endothelial progenitor cells (EPCs), but the effect of TNPs on circulating EPCs and their activity in humans remained unclear. This study aimed to explore the influence of TNPs on circulating EPCs with surface markers of CD34, CD133, and/or KDR, and colony-forming function plus migration activity of early EPCs derived from cultured peripheral blood mononuclear cells before and after TNP treatments in young healthy nonsmokers. In parallel, pulse wave analysis (PWA) was applied to evaluate the vascular effect of TNP treatments. Twenty-one participants (25.8 ± 3.6 years old, 10 males) used TNP (nicotine: 4.2 mg/day) for 7 consecutive days. During the treatment, the CD34+ EPCs progressively increased in number. In addition, the number of EPCs positive for CD34/KDR, CD133, and CD34/CD133 were also increased on day 7 of the treatment. Furthermore, the early EPC colony-forming function and migration activity were increased with the plasma cotinine level positively correlating with change in colony-forming unit number. PWA analyses on day 7, compared with pretreatment, did not show significant change except diastolic pressure time index, which was prolonged and implied potential vascular benefit. In conclusion, 7-day TNP treatments could be a practical strategy to enhance angiogenesis of circulating EPCs to alleviate tissue ischemia without any hemodynamic concern.
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Movimento Celular , Cotinina , Células Progenitoras Endoteliais , Hemodinâmica , Nicotina , Adesivo Transdérmico , Humanos , Células Progenitoras Endoteliais/efeitos dos fármacos , Células Progenitoras Endoteliais/metabolismo , Masculino , Adulto , Nicotina/administração & dosagem , Nicotina/sangue , Feminino , Adulto Jovem , Cotinina/sangue , Movimento Celular/efeitos dos fármacos , Hemodinâmica/efeitos dos fármacos , não Fumantes , Células Cultivadas , Análise de Onda de Pulso , Dispositivos para o Abandono do Uso de Tabaco/efeitos adversos , Administração CutâneaRESUMO
During development, activation of the complement pathway, an extracellular proteolytic cascade, results in microglia-dependent synaptic elimination via complement receptor 3 (CR3). Here, we report that decreased connectivity caused by overexpression of C4 (C4-OE), a schizophrenia-associated gene, is CR3 independent. Instead, C4-OE triggers GluR1 degradation through an intracellular mechanism involving endosomal trafficking protein SNX27, resulting in pathological synaptic loss. Moreover, the connectivity deficits associated with C4-OE were rescued by increasing levels of SNX27, linking excessive complement activity to an intracellular endolysosomal recycling pathway affecting synapses.
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Novel amphipathic derivative of chitosan (carboxymethyl-hexanoyl chitosan, CHC) was made into mats of nanofibers (approximately 100 nm) via electrospinning. The resulting mats were further cross-linked with genipin. The morphology of CHC nanofibers was examined using a field emission scanning electron microscope (FESEM). The optimum parameters of CHC nanofiber was achieved when the CHC concentration was 4 wt% and electrospinning was conducted with a voltage of 20 kV over a distance of 10 cm. The characterizations of biocompatibility, hemocompatibility, and anti-bacterial activity of the nanofibers were also investigated. The results show that CHC nanofibers still preserved antibacterial activity and thrombogeneicity owing to those residual amino groups of chitosan and exhibit high biocompatibility for L929 fibroblast test. Thus CHC exhibited the potential to serve as a novel wound dressing and surgical implants application by these advanced features.
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Fenômenos Fisiológicos Bacterianos/efeitos dos fármacos , Materiais Biocompatíveis/síntese química , Materiais Biocompatíveis/farmacologia , Quitosana/química , Quitosana/farmacologia , Nanoestruturas/química , Próteses e Implantes , Antibacterianos/síntese química , Antibacterianos/farmacologia , Eletroquímica/métodos , Teste de Materiais , Nanoestruturas/administração & dosagem , RotaçãoRESUMO
The Internet of Medical Things (IoMT) is an emerging technology in the healthcare revolution which provides real-time healthcare information communication and reasonable medical resource allocation. The COVID-19 pandemic has had a significant effect on people's lives and has affected healthcare capacities. It is important for integrated IoMT platform development to overcome the global pandemic challenges. This study proposed the national IoMT platform strategy portfolio decision-making model from the non-financial (technology, organization, environment) and financial perspectives. As a solution to the decision problem, initially, the decision-making trial and evaluation laboratory (DEMATEL) technology were employed to capture the cause-effect relationship based on the perspectives and criteria obtained from the insight of an expert team. The analytic network process (ANP) and pairwise comparisons were then used to determine the weights for the strategy. Simultaneously, this study incorporated IoMT platform resource limitations into the zero-one goal programming (ZOGP) method to obtain an optimal portfolio selection for IoMT platform strategy planning. The results showed that the integrated MCDM method produced reasonable results for selecting the most appropriate IoMT platform strategy portfolio when considering resource constraints such as system installation costs, consultant fees, infrastructure costs, reduction of medical staff demand, and improvement rates for diagnosis efficiency. The decision-making model of the IoMT platform in this study was conclusive and significantly compelling to aid government decision makers in concentrating their efforts on planning IoMT strategies in response to various pandemic and medical resource allocations.
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A 72-year-old man presented with altered consciousness. His past medical history included left renal cell carcinoma status post nephrectomy 3 years earlier, end-stage renal disease with regular hemodialysis, and central venous obstruction with stenting at the right subclavian vein and superior vena cava 8 months earlier. He was intubated and placed on a mechanical ventilator and inotropes for managing respiratory failure and shock. After numerous tests, it was evident that a right atrial mass was hindering blood flow into the right ventricle and causing blood to flow back into the peripheral venous system. This could cause obstructive cardiogenic shock and fluctuating cutaneous varices. The patient refused further intervention and died from multiple organ failure. This unusual phenomenon can provide a clue for the discovery of atrial masses in dialysis patients.
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Falência Renal Crônica , Varizes , Idoso , Humanos , Falência Renal Crônica/complicações , Falência Renal Crônica/diagnóstico , Falência Renal Crônica/terapia , Masculino , Diálise Renal/efeitos adversos , Veia Subclávia , Varizes/complicações , Varizes/diagnóstico , Varizes/terapia , Veia Cava SuperiorRESUMO
BACKGROUND: The alcohol patch test (APT) can detect aldehyde dehydrogenase (ALDH) genetic polymorphisms used to diagnose cutaneous erythema. However, the subjective results can vary owing to confounding factors. The hue-saturation-value (HSV) model provides an objective means of image analysis with APT. METHODS: This study enrolled 57 participants (27.7 ± 9.0 years, 52.6% females) with ALDH2*1/*1, ALDH2*1/*2, and ALDH2*2/*2 percentages of 50.9%, 43.8%, and 5.3%, respectively. In total, 56 APT protocols were applied and analyzed employing both visual inspection and the HSV model. The value of the delta standard deviation (SD) of the hue histogram, which manifests the difference between the APT reaction and the baseline skin color, was obtained using the HSV model. The receiver operating characteristic (ROC) curve and area under the ROC curve (AUC) were used to predict the ALDH2*2 allele with the HSV model. RESULTS: Upon visual inspection, a maximal Youden index with a sensitivity of 82.1% and a specificity of 96.6% was determined for the ALDH2 genetic mutation. Using the delta SD of hue obtained in the HSV model, a maximal Youden index with 85.7% sensitivity and 96.6% specificity was determined using the ROC curve analysis (AUC = 0.948, p < 0.001). Thus, the use of the HSV model analysis with APT resulted in equal specificity, but better sensitivity, compared to those obtained upon visual inspection. CONCLUSION: The HSV model took into account the potential confounding factors, and thus, could help in the prediction of ALDH2 genetic polymorphisms.
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Álcool Desidrogenase , Polimorfismo Genético , Álcool Desidrogenase/genética , Aldeído-Desidrogenase Mitocondrial/genética , Etanol , Feminino , Genótipo , Humanos , Masculino , Testes do EmplastroRESUMO
GP.Mur, a red blood cell (RBC) hybrid protein encoded by glycophorin B-A-B, increases expression of erythroid band 3 (Anion Exchanger-1, SLC4A1). GP.Mur is extremely rare but has a prevalence of 1-10% in regions of Southeast Asia. We unexpectedly found slightly higher blood pressure (BP) among healthy Taiwanese adults with GP.Mur. Since band 3 has been suggested to interact with hemoglobin (Hb) to modulate nitric oxide (NO)-dependent hypoxic vasodilation during the respiratory cycle, we hypothesized that GP.Mur red cells could exert differentiable effects on vascular tone. Here we recruited GP.Mur-positive and GP.Mur-negative elite male college athletes, as well as age-matched, GP.Mur-negative non-athletes, for NO-dependent flow-mediated dilation (FMD) and NO-independent dilation (NID). The subjects were also tested for plasma nitrite and nitrate before and after arterial occlusion in FMD. GP.Mur+ and non-GP.Mur athletes exhibited similar heart rates and blood pressure, but GP.Mur+ athletes showed significantly lower FMD (4.8 ± 2.4%) than non-GP.Mur athletes (6.5 ± 2.1%). NO-independent vasodilation was not affected by GP.Mur. As Hb controls intravascular NO bioavailability, we examined the effect of Hb on limiting FMD and found it to be significantly stronger in GP.Mur+ subjects. Biochemically, plasma nitrite levels were directly proportional to individual band 3 expression on the red cell membrane. The increase of plasma nitrite triggered by arterial occlusion also showed small dependency on band 3 levels in non-GP.Mur subjects. By the GP.Mur comparative study, we unveiled comodulation of NO-dependent vasodilation by band 3 and Hb, and verified the long-pending role of erythroid band 3 in this process.
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Aldehyde dehydrogenase 2 (ALDH2) rs671 polymorphism is a common genetic variant in Asians that is responsible for defective toxic aldehyde and lipid peroxidation metabolism after alcohol consumption. The extent to which low alcohol consumption may cause atrial substrates to trigger atrial fibrillation (AF) development in users with ALDH2 variants remains to be determined. We prospectively enrolled 249 ethnic Asians, including 56 non-drinkers and 193 habitual drinkers (135 (70%) as ALDH2 wild-type: GG, rs671; 58 (30%) as ALDH2 variants: G/A or A/A, rs671). Novel left atrial (LA) mechanical substrates with dynamic characteristics were assessed using a speckle-tracking algorithm and correlated to daily alcohol consumption and ALDH2 genotypes. Despite modest and comparable alcohol consumption by the habitual alcohol users (14.3 [8.3~28.6] and 12.3 [6.3~30.7] g/day for those without and with ALDH2 polymorphism, p = 0.31), there was a substantial and graded increase in the 4-HNE adduct and prolonged PR, and a reduction in novel LA mechanical parameters (including peak atrial longitudinal strain (PALS) and phasic strain rates (reservoir, conduit, and booster pump functions), p < 0.05), rather than an LA emptying fraction (LAEF) or LA volume index across non-drinkers, and in habitual drinkers without and with ALDH2 polymorphism (all p < 0.05). The presence of ALDH2 polymorphism worsened the association between increasing daily alcohol dose and LAEF, PALS, and phasic reservoir and booster functions (all Pinteraction: <0.05). Binge drinking superimposed on regular alcohol use exclusively further worsened LA booster pump function compared to regular drinking without binge use (1.66 ± 0.57 vs. 1.97 ± 0.56 1/s, p = 0.001). Impaired LA booster function further independently helped to predict AF after consideration of the CHARGE-AF score (adjusted 1.68 (95% CI: 1.06-2.67), p = 0.028, per 1 z-score increment). Habitual modest alcohol consumption led to mechanical LA substrate formation in an ethnic Asian population, which was more pronounced in subjects harboring ALDH2 variants. Impaired LA booster functions may serve as a useful predictor of AF in such populations.
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Fibrilação Atrial , Consumo de Bebidas Alcoólicas , Humanos , Polimorfismo Genético , Fatores de RiscoRESUMO
There is an established link between cardiometabolic abnormality, central arterial stiffness, and preserved ejection fraction heart failure (HFpEF). Adipocyte free fatty acid binding protein (a-FABP) has been shown to signal endothelial dysfunction through fatty acid toxicity, though its role in mediating ventricular-arterial dysfunction remains unclear. We prospectively examined the associations of a-FABP with central arterial pressure using non-invasive applanation tonometry (SphygmoCor) and cardiac structure/function (i.e., tissue Doppler imaging [TDI] and global longitudinal myocardial strain [GLS]) in patients with cardiometabolic (CM) risk (n = 150) and HFpEF (n = 50), with healthy volunteers (n = 49) serving as a control. We observed a graded increase of a-FABP across the healthy controls, CM individuals, and HFpEF groups (all paired p < 0.05). Higher a-FABP was independently associated with higher central systolic and diastolic blood pressures (CSP/CPP), increased arterial augmentation index (Aix), lower early myocardial relaxation velocity (TDI-e'), higher left ventricle (LV) filling (E/TDI-e') and worsened GLS (all p < 0.05). During a median of 3.85 years (interquartile range: 3.68-4.62 years) follow-up, higher a-FABP (cutoff: 24 ng/mL, adjusted hazard ratio: 1.01, 95% confidence interval: 1.001-1.02, p = 0.04) but not brain natriuretic peptide, and higher central hemodynamic indices were related to the incidence of heart failure (HF) in fully adjusted Cox models. Furthermore, a-FABP improved the HF risk classification over central hemodynamic information. We found a mechanistic pathophysiological link between a-FABP, central arterial stiffness, and myocardial dysfunction. In a population with a high metabolic risk, higher a-FABP accompanied by worsened ventricular-arterial coupling may confer more unfavorable outcomes in HFpEF.
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Cardiomiopatias/sangue , Proteínas de Ligação a Ácido Graxo/sangue , Insuficiência Cardíaca/sangue , Rigidez Vascular , Idoso , Pressão Sanguínea , Cardiomiopatias/diagnóstico por imagem , Estudos de Casos e Controles , Ecocardiografia , Feminino , Insuficiência Cardíaca/diagnóstico por imagem , Hemodinâmica , Humanos , Masculino , Manometria , Pessoa de Meia-Idade , Estudos Prospectivos , Volume Sistólico , Rigidez Vascular/fisiologiaRESUMO
Among 2085 asymptomatic subjects (age: 51.0±10.7 years, 41.3% female) with data available on common carotid artery diameter (CCAD) and circulating total white blood cell (WBC) counts, higher circulating leukocytes positively correlated with higher high sensitivity C-reactive protein (hs-CRP).Higher WBC/segmented cells and monocyte counts were independently associated with greater relative wall thicknesses and larger CCADs,which in generalweremore pronounced in men and obese subjects (body mass index ≥ 25kg/m2) (all P interaction: < 0.05). Using multivariate adjusting models, only the monocyte count independently predicted theleft ventricularmass index (LVMi) (ß-Coef: 0.06, p = 0.01). Higher circulating WBC, segmented,and monocyte counts and a greater CCAD were all independently associated with a higher risk of heart failure (HF)/all-cause death during a median of 12.1 years of follow-up in fully adjusted models, with individuals manifesting both higher CCADs and monocyte countsincurring the highest risk of HF/death (adjusted hazard ratio: 2.81, 95% CI: 1.57. -5.03, p< 0.001; P interaction, 0.035; lower CCAD/lower monocyte as reference). We conclude that a higher monocyte count is associated with cardiac remodeling and carotid artery dilation.Both an elevated monocyte count and a larger CCAD may indicate a specific phenotype that confers the highest risk of HF, which likely signifies the role of circulating monocytes in the pathophysiology of heart failure with preserved ejection fraction (HFpEF).
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A hydrogel-based functional hybrid with highly uniformly dispersed nanoparticulate CdS semiconductors is proposed. The hybrid is synthesized using an in situ polymerization following an in situ chemical reduction, where the resulting particle size and the distribution of CdS nanocrystals (NCs) can be narrowly manipulated. The hybrids, containing a relatively small amount of the CdS NCs, exhibit a pronounced photoluminescence spectrum shift when in contact with a number of dielectric liquids and such a pronounced dielectric-confinement effect has been experimentally verified and modeled in this study. The sensing capability of the hybrids with respect to dielectric liquids or molecules can be optically characterized and varied depending upon the intensity of the dielectric environment surrounding the hybrids. This work suggests that the transparent, nanoporous CdS-pHEMA hybrids can be used as highly efficient optical sensing materials.
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Compostos de Cádmio/química , Medições Luminescentes/métodos , Modelos Químicos , Nanoestruturas/ultraestrutura , Nanotecnologia/métodos , Poli-Hidroxietil Metacrilato/química , Compostos de Selênio/química , Soluções/química , Simulação por Computador , Cristalização/métodos , Impedância Elétrica , Substâncias Macromoleculares/química , Teste de Materiais , Conformação Molecular , Nanoestruturas/química , Tamanho da Partícula , Porosidade , Refratometria , Soluções/análise , Propriedades de SuperfícieRESUMO
A novel electro-activated Cu/pHEMA nanocomposite was fabricated by coupling nano copper particles with poly(2-hydroxyethyl methacrylate) (pHEMA) matrix. The nano-sized copper particles ranging from 5 nm to 10 nm were in-situ synthesized in the presence of three-dimensional polymer matrixes by photo-polymerization of the copper ions with the HEMA monomer and followed by a strong reducing reaction. The electrochemical behaviors of the Cu/pHEMA nanocomposite were charcterized by cyclic voltammetry and alternating current impedance method. The results showed that the redox behavior of Cu/pHEMA nanocomposite was controlled by the crystallinity of copper particles and the interaction between copper and pHEMA.
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Alzheimer's disease (AD) is characterized by the accumulation of neurotoxic amyloid-ß (Aß) peptides consisting of 39-43 amino acids, proteolytically derived fragments of the amyloid-ß protein precursor (AßPP), and the accumulation of the hyperphosphorylated microtubule-associated protein tau. Inhibiting Aß production may reduce neurodegeneration and cognitive dysfunction associated with AD. We have previously used an AßPP-firefly luciferase enzyme complementation assay to conduct a high throughput screen of a compound library for inhibitors of AßPP dimerization, and identified a compound that reduces Aß levels. In the present study, we have identified an analog, compound Y10, which also reduced Aß. Initial kinase profiling assays identified the receptor tyrosine kinase cKit as a putative Y10 target. To elucidate the precise mechanism involved, AßPP phosphorylation was examined by IP-western blotting. We found that Y10 inhibits cKit phosphorylation and increases AßPP phosphorylation mainly on tyrosine residue Y743, according to AßPP751 numbering. A known cKit inhibitor and siRNA specific to cKit were also found to increase AßPP phosphorylation and lower Aß levels. We also investigated a cKit downstream signaling molecule, the Shp2 phosphatase, and found that known Shp2 inhibitors and siRNA specific to Shp2 also increase AßPP phosphorylation, suggesting that the cKit signaling pathway is also involved in AßPP phosphorylation and Aß production. We further found that inhibitors of both cKit and Shp2 enhance AßPP surface localization. Thus, regulation of AßPP phosphorylation by small molecules should be considered as a novel therapeutic intervention for AD.
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Peptídeos beta-Amiloides/metabolismo , Precursor de Proteína beta-Amiloide/metabolismo , Proteínas Proto-Oncogênicas c-kit/metabolismo , Transdução de Sinais/efeitos dos fármacos , Peptídeos beta-Amiloides/efeitos dos fármacos , Precursor de Proteína beta-Amiloide/efeitos dos fármacos , Western Blotting , Eletroforese em Gel de Poliacrilamida , Ensaio de Imunoadsorção Enzimática , Células HEK293 , HumanosRESUMO
Phytohormone indole-3-acetic acid (IAA) is the most common naturally occurring and most thoroughly studied plant growth regulator. Microbial synthesis of IAA has long been known. Microbial IAA biosynthesis has been proposed as possibly occurring through multiple pathways, as has been proven in plants. However, the biosynthetic pathways of IAA and the ecological roles of IAA in yeast have not been widely studied. In this study, we investigated the variation in IAA production and its effect on the growth of Saccharomyces cerevisiae and its closest relative Saccharomyces paradoxus yeasts from diverse ecological sources. We found that almost all Saccharomyces yeasts produced IAA when cultured in medium supplemented with the primary precursor of IAA, L-tryptophan (L-Trp). However, when cultured in medium without L-Trp, IAA production was only detected in three strains. Furthermore, exogenous added IAA exerted stimulatory and inhibitory effects on yeast growth. Interestingly, a negative correlation was observed between the amount of IAA production in the yeast cultures and the IAA inhibition ratio of their growth.