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1.
Chem Biodivers ; 20(1): e202200626, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36448941

RESUMO

The purpose of this study is to optimize the extraction process and study antioxidant activity of Polysaccharide extracted from Centipeda minima. The Box-Behnken design-response surface methodology was adopted to optimize the extraction process of polysaccharides from Centipeda minima. We purified the crude polysaccharides from Centipeda minima, as well as determined the purity, monosaccharide composition, and molecular weight of the purified fraction. Fourier transform infrared spectrometer (FT-IR) and scanning electron microscopy (SEM) were used to analyze the structural features of the polysaccharides. Further, we investigated the antioxidant activities of different fractions of polysaccharides. Consequently, the results showed that the optimum extraction conditions for polysaccharides were: a liquid-solid ratio of 26 mL/g, extraction temperature of 85.5 °C, and extraction time of 2.4 h. Moreover, the yield of polysaccharides measured under these conditions was close to the predicted value. After purification, we obtained four components of Centipeda minima polysaccharides (CMP). The purity, monosaccharide composition, molecular weight, and structural characteristics of CMP were different, but with similar infrared absorption spectra. CMP exhibited a typical infrared absorption characteristic of a polysaccharide. Besides, CMP displayed good antioxidant activity, with potential to scavenge DPPH radical, hydroxyl radical, and superoxide radical. Therefore, this study provides a reference for future research on the structure and biological activity of CMP, and lays a theoretical foundation for food processing and medicinal development of CMP.


Assuntos
Antioxidantes , Polissacarídeos , Antioxidantes/química , Espectroscopia de Infravermelho com Transformada de Fourier , Polissacarídeos/química , Superóxidos/química , Monossacarídeos
2.
Plant J ; 106(3): 817-830, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33595147

RESUMO

Cowpea (Vigna unguiculata (L.) Walp.) is one of the most important legume crops planted worldwide, but despite decades of effort, cowpea transformation is still challenging due to inefficient Agrobacterium-mediated transfer DNA delivery, transgenic selection and in vitro shoot regeneration. Here, we report a highly efficient transformation system using embryonic axis explants isolated from imbibed mature seeds. We found that removal of the shoot apical meristem from the explants stimulated direct multiple shoot organogenesis from the cotyledonary node tissue. The application of a previously reported ternary transformation vector system provided efficient Agrobacterium-mediated gene delivery, while the utilization of spcN as selectable marker enabled more robust transgenic selection, plant recovery and transgenic plant generation without escapes and chimera formation. Transgenic cowpea plantlets developed exclusively from the cotyledonary nodes at frequencies of 4% to 37% across a wide range of cowpea genotypes. CRISPR/Cas-mediated gene editing was successfully demonstrated. The transformation principles established here could also be applied to other legumes to increase transformation efficiencies.


Assuntos
Edição de Genes/métodos , Sementes/genética , Vigna/genética , Agrobacterium/genética , Cotilédone/genética , Cotilédone/crescimento & desenvolvimento , Cotilédone/metabolismo , Técnicas de Transferência de Genes , Genoma de Planta/genética , Brotos de Planta/crescimento & desenvolvimento , Plantas Geneticamente Modificadas , Sementes/crescimento & desenvolvimento , Sementes/metabolismo , Transformação Genética , Vigna/crescimento & desenvolvimento , Vigna/metabolismo
4.
J Pharmacol Exp Ther ; 377(3): 316-325, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33722881

RESUMO

Ca2+/calmodulin-dependent protein kinase II (CaMKII) is upregulated in congestive heart failure (CHF), contributing to electrical, structural, and functional remodeling. CaMKII inhibition is known to improve CHF, but its direct cardiac effects in CHF remain unclear. We hypothesized that CaMKII inhibition improves cardiomyocyte function, [Ca2+]i regulation, and ß-adrenergic reserve, thus improving advanced CHF. In a 16-week study, we compared plasma neurohormonal levels and left ventricular (LV)- and myocyte-functional and calcium transient ([Ca2+]iT) responses in male Sprague-Dawley rats (10/group) with CHF induced by isoproterenol (170 mg/kg sq for 2 days). In rats with CHF, we studied the effects of the CaMKII inhibitor KN-93 or its inactive analog KN-92 (n = 4) (70 µg/kg per day, mini-pump) for 4 weeks. Compared with controls, isoproterenol-treated rats had severe CHF with 5-fold-increased plasma norepinephrine and about 50% decreases in ejection fraction (EF) and LV contractility [slope of LV end-systolic pressure-LV end-systolic volume relation (EES)] but increased time constant of LV relaxation (τ). They also showed significantly reduced myocyte contraction [maximum rate of myocyte shortening (dL/dtmax)], relaxation (dL/dtmax), and [Ca2+]iT Isoproterenol superfusion caused significantly fewer increases in dL/dtmax and [Ca2+]iT KN-93 treatment prevented plasma norepinephrine elevation, with increased basal and acute isoproterenol-stimulated increases in EF and EES and decreased τ in CHF. KN-93 treatment preserved normal myocyte contraction, relaxation, [Ca2+]iT, and ß-adrenergic reserve, whereas KN-92 treatment failed to improve LV and myocyte function, and plasma norepinephrine remained high in CHF. Thus, chronic CaMKII inhibition prevented CHF-induced activation of the sympathetic nervous system, restoring normal LV and cardiomyocyte basal and ß-adrenergic-stimulated contraction, relaxation, and [Ca2+]iT, thereby playing a rescue role in advanced CHF. SIGNIFICANCE STATEMENT: We investigated the therapeutic efficacy of late initiation of chronic Ca2+/calmodulin-dependent protein kinase II (CaMKII) inhibition on progression of advanced congestive heart failure (CHF). Chronic CaMKII inhibition prevented CHF-induced activation of the sympathetic nervous system and restored normal intrinsic cardiomyocyte basal and ß-adrenergic receptor-stimulated relaxation, contraction, and [Ca2+]i regulation, leading to reversal of CHF progression. These data provide new evidence that CaMKII inhibition is able and sufficient to rescue a failing heart, and thus cardiac CaMKII inhibition is a promising target for improving CHF treatment.


Assuntos
Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina , Animais , Insuficiência Cardíaca , Ratos , Ratos Sprague-Dawley
5.
Nano Lett ; 20(10): 7281-7286, 2020 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-32830984

RESUMO

On-chip signal processing at microwave frequencies is key for modern mobile communication. When one aims at small footprints, low power consumption, reprogrammable filters, and delay lines, magnons in low-damping ferrimagnets offer great promise. Ferromagnetic grating couplers have been reported to be specifically useful as microwave-to-magnon transducers. However, their interconversion efficiency is unknown and real-space measurements of the emitted magnon wavelengths have not yet been accomplished. Here, we image with subwavelength spatial resolution the magnon emission process into ferrimagnetic yttrium iron garnet (YIG) at frequencies up to 8 GHz. We evidence propagating magnons of a wavelength of 98.7 nm underneath the gratings, which enter the YIG without a phase jump. Counterintuitively, the magnons exhibit an even increased amplitude in YIG, which is unexpected and due to a further wavelength conversion process. Our results are of key importance for magnonic components, which efficiently control microwave signals on the nanoscale.

6.
Phys Rev Lett ; 124(2): 027203, 2020 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-32004033

RESUMO

Spin waves can probe the Dzyaloshinskii-Moriya interaction (DMI), which gives rise to topological spin textures, such as skyrmions. However, the DMI has not yet been reported in yttrium iron garnet (YIG) with arguably the lowest damping for spin waves. In this work, we experimentally evidence the interfacial DMI in a 7-nm-thick YIG film by measuring the nonreciprocal spin-wave propagation in terms of frequency, amplitude, and most importantly group velocities using all electrical spin-wave spectroscopy. The velocities of propagating spin waves show chirality among three vectors, i.e., the film normal direction, applied field, and spin-wave wave vector. By measuring the asymmetric group velocities, we extract a DMI constant of 16 µJ/m^{2}, which we independently confirm by Brillouin light scattering. Thickness-dependent measurements reveal that the DMI originates from the oxide interface between the YIG and garnet substrate. The interfacial DMI discovered in the ultrathin YIG films is of key importance for functional chiral magnonics as ultralow spin-wave damping can be achieved.

7.
Proc Natl Acad Sci U S A ; 113(39): 11040-5, 2016 09 27.
Artigo em Inglês | MEDLINE | ID: mdl-27621466

RESUMO

Micronutrient deficiencies are common in locales where people must rely upon sorghum as their staple diet. Sorghum grain is seriously deficient in provitamin A (ß-carotene) and in the bioavailability of iron and zinc. Biofortification is a process to improve crops for one or more micronutrient deficiencies. We have developed sorghum with increased ß-carotene accumulation that will alleviate vitamin A deficiency among people who rely on sorghum as their dietary staple. However, subsequent ß-carotene instability during storage negatively affects the full utilization of this essential micronutrient. We determined that oxidation is the main factor causing ß-carotene degradation under ambient conditions. We further demonstrated that coexpression of homogentisate geranylgeranyl transferase (HGGT), stacked with carotenoid biosynthesis genes, can mitigate ß-carotene oxidative degradation, resulting in increased ß-carotene accumulation and stability. A kinetic study of ß-carotene degradation showed that the half-life of ß-carotene is extended from less than 4 wk to 10 wk on average with HGGT coexpression.


Assuntos
Alimentos Fortificados , Sorghum/metabolismo , Vitamina E/metabolismo , beta Caroteno/metabolismo , Cromatografia Líquida de Alta Pressão , DNA Bacteriano/genética , Endosperma/metabolismo , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Sementes/metabolismo , Sorghum/enzimologia , Sorghum/genética
8.
Plant Biotechnol J ; 16(7): 1388-1395, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29327444

RESUMO

Sorghum is the fifth most widely planted cereal crop in the world and is commonly cultivated in arid and semi-arid regions such as Africa. Despite its importance as a food source, sorghum genetic improvement through transgenic approaches has been limited because of an inefficient transformation system. Here, we report a ternary vector (also known as cohabitating vector) system using a recently described pVIR accessory plasmid that facilitates efficient Agrobacterium-mediated transformation of sorghum. We report regeneration frequencies ranging from 6% to 29% in Tx430 using different selectable markers and single copy, backbone free 'quality events' ranging from 45% to 66% of the total events produced. Furthermore, we successfully applied this ternary system to develop transformation protocols for popular but recalcitrant African varieties including Macia, Malisor 84-7 and Tegemeo. In addition, we report the use of this technology to develop the first stable CRISPR/Cas9-mediated gene knockouts in Tx430.


Assuntos
Agrobacterium/genética , Engenharia Genética/métodos , Sorghum/genética , Sistemas CRISPR-Cas , Técnicas de Transferência de Genes , Marcadores Genéticos/genética , Vetores Genéticos/genética , Plantas Geneticamente Modificadas/genética , Transformação Genética/genética
9.
Org Biomol Chem ; 16(39): 7265-7273, 2018 10 10.
Artigo em Inglês | MEDLINE | ID: mdl-30259031

RESUMO

An efficient method for the synthesis of 3-halogeno-substituted 4-benzoylquinolin-2-(1H)-ones from N-(2-alkynylphenyl)-substituted trihaloacetamides has been developed, in which organic amines (TNPA and DIEA) act as the electron donors. In this carbocyclization reaction, a new C-C bond formation occurred regioselectively via a 6-exo-dig radical cyclization. A variety of useful functional groups are compatible with the reaction conditions. In this process, readily removable organic amines were employed and no heavy metal catalysts were required.

10.
Org Biomol Chem ; 16(30): 5483-5491, 2018 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-30024586

RESUMO

An efficient Ag(i)-catalyzed method for the synthesis of 5H-benzo[b]naphtho[2,3-f]azepine-6,11-diones from 2-(2-ethynylphenyl)amino substituted 1,4-naphthoquinones has been developed. In this transformation new C-C bond formation occurred regioselectively via a 7-endo-dig cyclization. The related 13-iodine substituted benzazepine derivatives could also be produced exclusively by the I2-induced carbocyclization reaction of 2-(2-alkynylphenyl)amino substituted 1,4-naphthoquinones. This process has advantages such as mild reaction conditions and tolerance of a broad range of functional groups.

11.
Curr Hypertens Rep ; 19(2): 16, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28233239

RESUMO

PURPOSE OF THE REVIEW: Drugs targeting the renin-angiotensin system (RAS), namely angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers, are the most commonly prescribed drugs for patients with or at risk for cardiovascular events. However, new treatment strategies aimed at mitigating the rise of the heart failure pandemic are warranted because clinical trials show that RAS blockers have limited benefits in halting disease progression. The main goal of this review is to put forward the concept of an intracrine RAS signaling through the novel angiotensin-(1-12)/chymase axis as the main source of deleterious angiotensin II (Ang II) in cardiac maladaptive remodeling leading to heart failure (HF). RECENT FINDINGS: Expanding traditional knowledge, Ang II can be produced in tissues independently from the circulatory renin-angiotensin system. In the heart, angiotensin-(1-12) [Ang-(1-12)], a recently discovered derivative of angiotensinogen, is a precursor of Ang II, and chymase rather than ACE is the main enzyme contributing to the direct production of Ang II from Ang-(1-12). The Ang-(1-12)/chymase axis is an independent intracrine pathway accounting for the trophic, contractile, and pro-arrhythmic Ang II actions in the human heart. Ang-(1-12) expression and chymase activity have been found elevated in the left atrial appendage of heart disease subjects, suggesting a pivotal role of this axis in the progression of HF. Recent meta-analysis of large clinical trials on the use of ACE inhibitors and angiotensin receptor blockers in cardiovascular disease has demonstrated an imbalance between patients that significantly benefit from these therapeutic agents and those that remain at risk for heart disease progression. Looking to find an explanation, detailed investigation on the RAS has unveiled a previously unrecognized complexity of substrates and enzymes in tissues ultimately associated with the production of Ang II that may explain the shortcomings of ACE inhibition and angiotensin receptor blockade. Discovery of the Ang-(1-12)/chymase axis in human hearts, capable of producing Ang II independently from the circulatory RAS, has led to the notion that a tissue-delimited RAS signaling in an intracrine fashion may account for the deleterious effects of Ang II in the heart, contributing to the transition from maladaptive cardiac remodeling to heart failure. Targeting intracellular RAS signaling may improve current therapies aimed at reducing the burden of heart failure.


Assuntos
Antagonistas de Receptores de Angiotensina/uso terapêutico , Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Angiotensinogênio/metabolismo , Quimases/metabolismo , Insuficiência Cardíaca/tratamento farmacológico , Hipertensão/tratamento farmacológico , Fragmentos de Peptídeos/metabolismo , Sistema Renina-Angiotensina/fisiologia , Animais , Humanos , Receptores de Angiotensina/fisiologia , Sistema Renina-Angiotensina/efeitos dos fármacos
12.
Org Biomol Chem ; 15(9): 2020-2032, 2017 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-28203674

RESUMO

An efficient and low-cost method for the synthesis of 4-substituted quinolin-2-(1H)-ones has been developed. In the presence of TBHP, the cobalt(ii)-catalyzed carbocyclization reactions of arylethenyl substituted α-bromo-N-phenylacetamides, involving sequential 6-exo-trig radical cyclization, t-butylperoxy radical cross-coupling reaction and the base-promoted ionic Kornblum-DeLaMare reaction, produced 4-benzoylquinolin-2-(1H)-ones. A variety of useful functional groups such as methoxy, fluoro, chloro, bromo, methoxycarbonyl, and cyano groups, are compatible with the reaction conditions. This strategy was further applied to arylethynyl substituted α-bromo-N-phenylacetamides, and 4-benzylquinolin-2-(1H)-ones were formed effectively.

13.
Am J Physiol Heart Circ Physiol ; 311(2): H404-14, 2016 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-27233763

RESUMO

Although it is well-known that excess renin angiotensin system (RAS) activity contributes to the pathophysiology of cardiac and vascular disease, tissue-based expression of RAS genes has given rise to the possibility that intracellularly produced angiotensin II (Ang II) may be a critical contributor to disease processes. An extended form of angiotensin I (Ang I), the dodecapeptide angiotensin-(1-12) [Ang-(1-12)], that generates Ang II directly from chymase, particularly in the human heart, reinforces the possibility that an alternative noncanonical renin independent pathway for Ang II formation may be important in explaining the mechanisms by which the hormone contributes to adverse cardiac and vascular remodeling. This review summarizes the work that has been done in evaluating the functional significance of Ang-(1-12) and how this substrate generated from angiotensinogen by a yet to be identified enzyme enhances knowledge about Ang II pathological actions.


Assuntos
Angiotensina II/metabolismo , Angiotensinogênio/metabolismo , Coração/fisiopatologia , Miocárdio/metabolismo , Fragmentos de Peptídeos/metabolismo , Sistema Renina-Angiotensina , Animais , Quimases , Humanos , Remodelação Vascular/fisiologia , Remodelação Ventricular/fisiologia
14.
J Pharmacol Exp Ther ; 357(3): 545-53, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-27026682

RESUMO

In heart failure (HF), the impaired left ventricular (LV) arterial coupling and diastolic dysfunction present at rest are exacerbated during exercise. C-type natriuretic peptide (CNP) is elevated in HF; however, its functional effects are unclear. We tested the hypotheses that CNP with vasodilating, natriuretic, and positive inotropic and lusitropic actions may prevent this abnormal exercise response after HF. We determined the effects of CNP (2 µg/kg plus 0.4 µg/kg per minute, i.v., 20 minutes) on plasma levels of cGMP before and after HF and assessed LV dynamics during exercise in 10 chronically instrumented dogs with pacing-induced HF. Compared with the levels before HF, CNP infusion caused significantly greater increases in cGMP levels after HF. After HF, at rest, CNP administration significantly reduced LV end-systolic pressure (PES), arterial elastance (EA), and end-diastolic pressure. The peak mitral flow (dV/dtmax) was also increased owing to decreased minimum LVP (LVPmin) and the time constant of LV relaxation (τ) (P < 0.05). In addition, LV contractility (EES) was increased. The LV-arterial coupling (EES/EA) was improved. The beneficial effects persisted during exercise. Compared with exercise in HF preparation, treatment with CNP caused significantly less important increases in PES but significantly decreased τ (34.2 vs. 42.6 ms) and minimum left ventricular pressure with further augmented dV/dtmax Both EES, EES/EA (0.87 vs. 0.32) were increased. LV mechanical efficiency improved from 0.38 to 0.57 (P < 0.05). After HF, exogenous CNP produces arterial vasodilatation and augments LV contraction, relaxation, diastolic filling, and LV arterial coupling, thus improving LV performance at rest and restoring normal exercise responses after HF.


Assuntos
Insuficiência Cardíaca/fisiopatologia , Peptídeo Natriurético Tipo C/farmacologia , Condicionamento Físico Animal , Recuperação de Função Fisiológica/efeitos dos fármacos , Descanso/fisiologia , Disfunção Ventricular Esquerda/tratamento farmacológico , Disfunção Ventricular Esquerda/fisiopatologia , Animais , Diástole/efeitos dos fármacos , Cães , Relação Dose-Resposta a Droga , Feminino , Hemodinâmica/efeitos dos fármacos , Humanos , Masculino , Peptídeo Natriurético Tipo C/uso terapêutico
15.
J Nanosci Nanotechnol ; 16(3): 2719-24, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27455697

RESUMO

Zn(1-x)Co(x)O (x = 0-0.07) single-crystalline nanorods were prepared by a modified microemulsion route. The crystalline structure, morphology, optical, and hysteresis loop at low and room temperature of as-prepared materials were characterized by XRD, TEM, PL spectra, and magnetic measurement respectively. The nanorods are 80-250 nm in diameter and about 3 µm in length. X-ray diffraction data, TEM images confirm that the materials synthesized in optimal conditions are ZnO:Co single crystalline solid solution without any impurities related to Co. The PL spectra show that the ferromagnetic samples exhibit strong Zn interstitials and oxygen vacancy emission indicating defects may stabilize ferromagnetic order in the obtained diluted magnetic semiconductors. Magnetic measurements show that the Zn(1-x)Co(x)O nanorods exist obvious ferromagnetic characteristics with T(c) above 300 K. M(s) and coercivities first increase and then decrease with dopant concentration increasing, reaching the highest for 3% doping level. The structural and magnetic properties of these samples support the hypothesis that the FM of DMS nanorods is due to a defect mediated mechanism instead of cobalt nanoclusters and carrier mediated.


Assuntos
Cobalto/química , Magnetismo , Nanotubos , Oxigênio/química , Óxido de Zinco/química , Microscopia Eletrônica de Transmissão , Difração de Raios X
16.
J Nanosci Nanotechnol ; 16(3): 2929-32, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27455736

RESUMO

Non-Stoichiometric La2Zr2O7 (La(2-x)Zr(2-y)O7) Nanocrystal was synthesized by a simple sol-gel method. The crystalline structure, oxygen vacancy concentration, thermal expansion coefficient, as well as the fracture toughness of as-prepared materials were charactered by XRD, TG-DSC, PL spectra, dilatometer, and electronic universal testing machine respectively. The crystal structure of La2Zr2O7 is of the cubic type while lattice parameter increases with the deviatation of Zr4+ and La3+ from Stoichiometric La2Zr2O7 increasing. The average linear thermal expansion coefficient of non-stoichiometric La2Zr2O7 is obviously bigger than that of La2Zr2O7 in the temperature range between 150 degrees C and 950 degrees C. The fracture toughness of La(2-x)Zr(2-y)O7 increases with x and y increasing up to x = 0.3 and y = 0.25.


Assuntos
Lantânio/química , Nanopartículas , Zircônio/química , Géis , Difração de Raios X
17.
J Mol Cell Cardiol ; 83: 73-87, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25754674

RESUMO

Heart failure with preserved ejection fraction (HFpEF) is the most common form of heart failure (HF) in older adults, particularly women, and is increasing in prevalence as the population ages. With morbidity and mortality on par with HF with reduced ejection fraction, it remains a most challenging clinical syndrome for the practicing clinician and basic research scientist. Originally considered to be predominantly caused by diastolic dysfunction, more recent insights indicate that HFpEF in older persons is typified by a broad range of cardiac and non-cardiac abnormalities and reduced reserve capacity in multiple organ systems. The globally reduced reserve capacity is driven by: 1) inherent age-related changes; 2) multiple, concomitant co-morbidities; 3) HFpEF itself, which is likely a systemic disorder. These insights help explain why: 1) co-morbidities are among the strongest predictors of outcomes; 2) approximately 50% of clinical events in HFpEF patients are non-cardiovascular; 3) clinical drug trials in HFpEF have been negative on their primary outcomes. Embracing HFpEF as a true geriatric syndrome, with complex, multi-factorial pathophysiology and clinical heterogeneity could provide new mechanistic insights and opportunities for progress in management. This article is part of a Special Issue entitled CV Aging.


Assuntos
Envelhecimento/patologia , Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Insuficiência Cardíaca/patologia , Insuficiência Cardíaca/terapia , Idoso , Envelhecimento/metabolismo , Animais , Enalapril/uso terapêutico , Terapia por Exercício , Feminino , Insuficiência Cardíaca/diagnóstico , Insuficiência Cardíaca/metabolismo , Humanos , Masculino , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Proteínas Recombinantes/uso terapêutico , Relaxina/uso terapêutico , Fatores de Risco , Volume Sistólico/efeitos dos fármacos , Rigidez Vascular/efeitos dos fármacos
18.
Infect Drug Resist ; 17: 2389-2399, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38903152

RESUMO

Objective: The most common extraintestinal pathogen and infection site is uropathogenic Escherichia coli (UPEC), which causes urinary tract infections (UTIs). UPEC is also a common pathogen in bloodstream infections; in severe cases, it can lead to death. Although host and bacterial virulence factors have been demonstrated to be associated with UTI pathogenesis, the role of the related contributing factors in UTI and urinary source bacteremia is not yet fully understood. This study aimed to compare and analyze the factors contributing to urinary bacteremia in patients with UTI. Methods: A total of 171 E. coli strains collected from patients with UTI and urinary source bacteremia at Chiayi Christian Hospital were used. Phylogenetic groups and virulence factors were determined using PCR. Drug resistance patterns were determined using the disk diffusion assay. Results: Previous studies have demonstrated that fimbriae and papGII may be associated with first-step infections and severe UTIs, respectively. As expected, highly virulent E. coli strains (belonging to the phylogenetic B2 and D groups) were dominant in the bacteremic UTI (90%) and UTI (86.27%) groups. However, our results showed that the UTI group had a significantly higher prevalence of sfa/focDE (belonging to the S and FIC fimbriae) than the bacteremic UTI group (29.4% vs 12.5%; p=0.008). In the bacteremic group, we found that sfa/focDE was only detected in highly virulent strains. The bacteremic UTI group had a significantly higher prevalence of papGII (belonging to P fimbriae) than the UTI group (55.8% vs 37.3%; p=0.026). In addition, the P fimbriae gene cluster, including papC, papEF, and papGII, was predominant in highly virulent strains. Notably, our results show that multidrug-resistant (MDR) strains were significantly less virulent than non MDR strains. Conclusion: Taken together, our results provide insights into the contributing factors in patients with UTI and urinary bacteremia.

19.
J Phys Condens Matter ; 36(36)2024 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-38565125

RESUMO

Magnonicsis a research field that has gained an increasing interest in both the fundamental and applied sciences in recent years. This field aims to explore and functionalize collective spin excitations in magnetically ordered materials for modern information technologies, sensing applications and advanced computational schemes. Spin waves, also known as magnons, carry spin angular momenta that allow for the transmission, storage and processing of information without moving charges. In integrated circuits, magnons enable on-chip data processing at ultrahigh frequencies without the Joule heating, which currently limits clock frequencies in conventional data processors to a few GHz. Recent developments in the field indicate that functional magnonic building blocks for in-memory computation, neural networks and Ising machines are within reach. At the same time, the miniaturization of magnonic circuits advances continuously as the synergy of materials science, electrical engineering and nanotechnology allows for novel on-chip excitation and detection schemes. Such circuits can already enable magnon wavelengths of 50 nm at microwave frequencies in a 5G frequency band. Research into non-charge-based technologies is urgently needed in view of the rapid growth of machine learning and artificial intelligence applications, which consume substantial energy when implemented on conventional data processing units. In its first part, the 2024 Magnonics Roadmap provides an update on the recent developments and achievements in the field of nano-magnonics while defining its future avenues and challenges. In its second part, the Roadmap addresses the rapidly growing research endeavors on hybrid structures and magnonics-enabled quantum engineering. We anticipate that these directions will continue to attract researchers to the field and, in addition to showcasing intriguing science, will enable unprecedented functionalities that enhance the efficiency of alternative information technologies and computational schemes.

20.
Plant J ; 70(4): 562-77, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22211474

RESUMO

3-methylcrotonyl CoA carboxylase (MCCase) is a nuclear-encoded, mitochondrial-localized biotin-containing enzyme. The reaction catalyzed by this enzyme is required for leucine (Leu) catabolism, and it may also play a role in the catabolism of isoprenoids and the mevalonate shunt. In Arabidopsis, two MCCase subunits (the biotinylated MCCA subunit and the non-biotinylated MCCB subunit) are each encoded by single genes (At1g03090 and At4g34030, respectively). A reverse genetic approach was used to assess the physiological role of MCCase in plants. We recovered and characterized T-DNA and transposon-tagged knockout alleles of the MCCA and MCCB genes. Metabolite profiling studies indicate that mutations in either MCCA or MCCB block mitochondrial Leu catabolism, as inferred from the increased accumulation of Leu. Under light deprivation conditions, the hyper-accumulation of Leu, 3-methylcrotonyl CoA and isovaleryl CoA indicates that mitochondrial and peroxisomal Leu catabolism pathways are independently regulated. This biochemical block in mitochondrial Leu catabolism is associated with an impaired reproductive growth phenotype, which includes aberrant flower and silique development and decreased seed germination. The decreased seed germination phenotype is only observed for homozygous mutant seeds collected from a parent plant that is itself homozygous, but not from a parent plant that is heterozygous. These characterizations may shed light on the role of catabolic processes in growth and development, an area of plant biology that is poorly understood.


Assuntos
Proteínas de Arabidopsis/genética , Carbono-Carbono Ligases/genética , Germinação/genética , Leucina/metabolismo , Subunidades Proteicas/genética , Sementes/genética , Acil Coenzima A/metabolismo , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Carbono-Carbono Ligases/metabolismo , Elementos de DNA Transponíveis/genética , DNA Bacteriano/genética , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Homozigoto , Microscopia Eletrônica de Varredura , Mitocôndrias/metabolismo , Mutagênese Insercional , Plantas Geneticamente Modificadas , Subunidades Proteicas/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Sementes/crescimento & desenvolvimento , Sementes/metabolismo
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