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1.
Dev Biol ; 475: 10-20, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33662357

RESUMO

microRNAs (miRNAs) are ~21-22 nucleotide (nt) RNAs that mediate broad post-transcriptional regulatory networks. However, genetic analyses have shown that the phenotypic consequences of deleting individual miRNAs are generally far less overt compared to their misexpression. This suggests that miRNA deregulation may have broader phenotypic impacts during disease situations. We explored this concept in the Drosophila eye, by screening for miRNAs whose misexpression could modify the activity of pro-apoptotic factors. Via unbiased and comprehensive in vivo phenotypic assays, we identify an unexpectedly large set of miRNA hits that can suppress the action of pro-apoptotic genes hid and grim. We utilize secondary assays to validate that a subset of these miRNAs can inhibit irradiation-induced cell death. Since cancer cells might seek to evade apoptosis pathways, we modeled this situation by asking whether activation of anti-apoptotic miRNAs could serve as "second hits". Indeed, while clones of the lethal giant larvae (lgl) tumor suppressor are normally eliminated during larval development, we find that diverse anti-apoptotic miRNAs mediate the survival of lgl mutant clones in third instar larvae. Notably, while certain anti-apoptotic miRNAs can target apoptotic factors, most of our screen hits lack obvious targets in the core apoptosis machinery. These data highlight how a genetic approach can reveal distinct and powerful activities of miRNAs in vivo, including unexpected functional synergies during disease or cancer-relevant settings.


Assuntos
Apoptose/genética , MicroRNAs/genética , Animais , Apoptose/fisiologia , Morte Celular/genética , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Olho/metabolismo , Proteínas do Olho/genética , Proteínas do Olho/metabolismo , Expressão Gênica/genética , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica/genética , Regulação da Expressão Gênica/fisiologia , Redes Reguladoras de Genes/genética , MicroRNAs/fisiologia , Neuropeptídeos/genética , Neuropeptídeos/metabolismo , Fenótipo , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/metabolismo
2.
FASEB J ; 35(5): e21614, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33908669

RESUMO

Alexander disease (AxD) caused by mutations in the coding region of GFAP is a neurodegenerative disease characterized by astrocyte dysfunction, GFAP aggregation, and Rosenthal fiber accumulation. Although how GFAP mutations cause disease is not fully understood, Rosenthal fibers could be induced by forced overexpression of human GFAP and this could be lethal in mice implicate that an increase in GFAP levels is central to AxD pathogenesis. Our recent studies demonstrated that intronic GFAP mutations cause disease by altering GFAP splicing, suggesting that an increase in GFAP isoform expression could lead to protein aggregation and astrocyte dysfunction that typify AxD. Here we test this hypothesis by establishing primary astrocyte cultures from transgenic mice overexpressing human GFAP. We found that GFAP-δ and GFAP-κ were disproportionately increased in transgenic astrocytes and both were enriched in Rosenthal fibers of human AxD brains. In vitro assembly studies showed that while the major isoform GFAP-α self-assembled into typical 10-nm filaments, minor isoforms including GFAP-δ, -κ, and -λ were assembly-compromised and aggregation prone. Lentiviral transduction showed that expression of these minor GFAP isoforms decreased filament solubility and increased GFAP stability, leading to the formation of Rosenthal fibers-like aggregates that also disrupted the endogenous intermediate filament networks. The aggregate-bearing astrocytes lost their normal morphology and glutamate buffering capacity, which had a toxic effect on neighboring neurons. In conclusion, our findings provide evidence that links elevated GFAP isoform expression with GFAP aggregation and impaired glutamate transport, and suggest a potential non-cell-autonomous mechanism underlying neurodegeneration through astrocyte dysfunction.


Assuntos
Doença de Alexander/patologia , Astrócitos/patologia , Proteína Glial Fibrilar Ácida/química , Proteína Glial Fibrilar Ácida/metabolismo , Ácido Glutâmico/metabolismo , Mutação , Agregados Proteicos , Doença de Alexander/metabolismo , Animais , Astrócitos/metabolismo , Humanos , Camundongos , Camundongos Transgênicos , Conformação Proteica , Isoformas de Proteínas
3.
J Formos Med Assoc ; 121(9): 1773-1785, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35094911

RESUMO

BACKGROUND/PURPOSE: The increasing prevalence of overweight and obese children and adolescents has been recognized as a public health threat worldwide. This study aimed to assess the effect of a stepwise lifestyle intervention in children and adolescents. METHODS: We developed a multidisciplinary clinic aimed at providing lifestyle interventions for obese children and adolescents. The program comprised three stages with stepwise goals: knowledge building (the first 4 weeks), habit consolidation (5-12 weeks), and self-monitoring (13-20 weeks). RESULTS: Of the 63 participants (age 11.6 ± 3.2 years) who entered the first stage of the program, 48, 22, and 15 completed the first, second and third stages (4, 12, and 20 weeks), respectively. In the first stage, significant improvement was noted in body weight, body mass index (BMI), BMI z-score, and waist circumference. Improvements in physical fitness performance were observed at 4 weeks in 3/5 items and at 12 weeks in 4/5 items. The decreases in body weight, BMI and BMI z-score were most prominent in the first two stages. In the third stage, participants maintained a stable body weight. In the 15 subjects who completed the whole program, BMI decreased from 29.3 ± 6.9 to 27.8 ± 6.1 (P = 0.001), and BMI z-score decreased from 3.06 ± 0.96 to 2.69 ± 0.91(P = 0.001). CONCLUSION: We developed a feasible multidisciplinary program based on knowledge education and individualized training. BMI and physical fitness scores can be used as early indicators of lifestyle change for obese children and adolescents.


Assuntos
Sobrepeso , Obesidade Infantil , Adolescente , Índice de Massa Corporal , Peso Corporal , Criança , Humanos , Estilo de Vida
4.
J Chem Phys ; 151(8): 084302, 2019 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-31470727

RESUMO

A suppressed-Doppler (Δν = 180 MHz) infrared spectrum of monodeuterated ammonium ions (NH3D+) has been obtained for the ν1 (symmetric) and ν4 (degenerate) N-H stretch bands via direct absorption high resolution IR laser spectroscopy in a planar slit jet discharge expansion. The ion is efficiently generated by H3 + protonation of NH2D in a discharge mixture of H2/NH2D, with the resulting expansion rapidly cooling the molecular ions into low rotational states. The first high-resolution infrared spectrum of ν1 is reported, as well as many previously unobserved transitions in the ν4 rovibrational manifold. Simultaneous observation of both ν1 and ν4 permits elucidation of both the vibrational ground and excited state properties of the ion, including rigorous benchmarking of band origins against high-level anharmonic ab initio theory as well as determination of the ν1:ν4 intensity ratio for comparison with bond-dipole model predictions. Ground-state combination differences from this work and earlier studies permit the rotational constants of NH3D+ to be determined to unprecedented accuracy, the results of which support previous laboratory and astronomical assignment of the 10-00 pure rotational transition and should aid future searches for other rotational transitions as well.

5.
J Chem Phys ; 148(1): 014304, 2018 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-29306286

RESUMO

Sub-Doppler infrared rovibrational transitions in the symmetric (v1) and antisymmetric (v6) NH stretch modes of the isotopomerically substituted ND2H2+ ammonium cation are reported for the first time in a slit jet discharge supersonic expansion spectrometer. The partially H/D substituted cation is generated by selective isotopic exchange of ND3 with H2O to form NHD2, followed by protonation with H3+ formed in the NHD2/H2/Ne slit-jet discharge expansion environment. Rotational assignment for ND2H2+ is confirmed rigorously by four line ground state combination differences, which agree to be within the sub-Doppler precision in the slit jet (∼9 MHz). Observation of both b-type (ν1) and c-type (ν6) bands enables high precision determination of the ground and vibrationally excited state rotational constants. From an asymmetric top Watson Hamiltonian analysis, the ground state constants are found to be A″ = 4.856 75(4) cm-1, B″ = 3.968 29(4) cm-1, and C″ = 3.446 67(6) cm-1, with band origins at 3297.5440(1) and 3337.9050(1) cm-1 for the v1 and v6 modes, respectively. This work permits prediction of precision microwave/mm-wave transitions, which should be invaluable in facilitating ongoing spectroscopic searches for partially deuterated ammonium cations in interstellar clouds and star-forming regions of the interstellar medium.

6.
J Chem Phys ; 149(14): 144303, 2018 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-30316288

RESUMO

High-resolution rotationally resolved spectra of the N-H stretch vibrational mode (ν 1) of jet-cooled ND3H+ ions are collected and analyzed in a sub-Doppler slit-jet infrared spectrometer. The isotopomeric ammonium ions are generated by proton transfer from H3 + to ND3 in a discharge of an ND3/H2 gas mixture, whereby the slit jet expansion cools the nascent ND3H+ ions into lower rotational states. Rotational assignments are confirmed by four-line combination differences that agree to within the spectrometer precision (9 MHz). Based on precision two-line ground-state combination differences and a symmetric top Hamiltonian, the B, D J , and D JK rotational constants for the ground vibrational state of ND3H+ are determined with high precision for the first time. Approximate rotational constants for the ν 1 excited state are also determined, with a band origin at 3316.8425(19) cm-1 and in remarkable (∼0.1 cm-1) agreement with high level anharmonic theoretical predictions by Guo and co-workers [J. Phys. Chem. A, 120, 2185 (2016)]. Our results allow us to predict several low-J pure rotational transitions of ND3H+, which we hope will support future studies of this important ion in laboratory and astronomical rotational spectroscopy.

7.
Biomed Microdevices ; 19(1): 13, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-28229307

RESUMO

Periosteum-derived cells was indicated to respond to mechanical force and have stem cell potential capable of differentiating into multiple tissue. Investigation of osteogenic activity under mechanical stimulation is important to understand the therapeutic conditions of fracture healing. In this work, a cell culture platform was developed for respectively providing isotropic and anisotropic axial strain. Primary rabbit periosteal cells were isolated and cultured in the chamber. Multi-axial tensile strain was received and osteogenic activity was investigated by mRNA expressions of CBFA1 and OPN. The highest mRNA expression was found in moderate strain (5-8%) under anisotropic axial strain. These results provided important foundation for further in vivo studies and development of tailor-made stretching rehabilitation equipment.


Assuntos
Técnicas de Cultura de Células/instrumentação , Osteogênese , Periósteo/citologia , Estresse Mecânico , Resistência à Tração , Animais , Subunidade alfa 1 de Fator de Ligação ao Core/genética , Periósteo/metabolismo , Pressão , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Coelhos
8.
J Chem Phys ; 146(19): 194307, 2017 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-28527463

RESUMO

The sub-Doppler CH-symmetric stretch (ν3) infrared absorption spectrum of a hydroxymethyl (CH2OH) radical is observed and analyzed with the radical formed in a slit-jet supersonic discharge expansion (Trot = 18 K) via Cl atom mediated H atom abstraction from methanol. The high sensitivity of the spectrometer and reduced spectral congestion associated with the cooled expansion enable first infrared spectroscopic observation of hydroxymethyl transitions from both ± symmetry tunneling states resulting from large amplitude COH torsional motion. Nuclear spin statistics due to exchange of the two methyl H-atoms aid in unambiguous rovibrational assignment of two A-type Ka = 0 ← 0 and Ka = 1 ← 1 bands out of each ± tunneling state, with additional spectral information obtained from spin-rotation splittings in P, Q, and R branch Ka = 1 ← 1 transitions that become resolved at low N. A high level ab initio potential surface (CCSD(T)-f12b/cc-pvnzf12 (n = 2,3)/CBS) is calculated in the large amplitude COH torsional and CH2 wag coordinates, which in the adiabatic approximation and with zero point correction predicts ground state tunneling splittings in good qualitative agreement with experiment. Of particular astrochemical interest, a combined fit of the present infrared ground state combination differences with recently reported millimeter-wave frequencies permits the determination of improved accuracy rotational constants for the ground vibrational state, which will facilitate ongoing millimeter/microwave searches for a hydroxymethyl radical in the interstellar medium.

9.
J Chem Phys ; 145(4): 044304, 2016 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-27475358

RESUMO

A series of CH stretch modes in phenyl radical (C6H5) has been investigated via high resolution infrared spectroscopy at sub-Doppler resolution (∼60 MHz) in a supersonic discharge slit jet expansion. Two fundamental vibrations of a1 symmetry, ν1 and ν2, are observed and rotationally analyzed for the first time, corresponding to in-phase and out-of-phase symmetric CH stretch excitation at the ortho/meta/para and ortho/para C atoms with respect to the radical center. The ν1 and ν2 band origins are determined to be 3073.968 50(8) cm(-1) and 3062.264 80(7) cm(-1), respectively, which both agree within 5 cm(-1) with theoretical anharmonic scaling predictions based on density functional B3LYP/6-311g++(3df,3dp) calculations. Integrated band strengths for each of the CH stretch bands are analyzed, with the relative intensities agreeing remarkably well with theoretical predictions. Frequency comparison with previous low resolution Ar-matrix spectroscopy [A. V. Friderichsen et al., J. Am. Chem. Soc. 123, 1977 (2001)] reveals a nearly uniform Δν ≈ + 10-12 cm(-1) blue shift between gas phase and Ar matrix values for ν1 and ν2. This differs substantially from the much smaller red shift (Δν ≈ - 1 cm(-1)) reported for the ν19 mode, and suggests a simple physical model in terms of vibrational mode symmetry and crowding due to the matrix environment. Finally, the infrared phenyl spectra are well described by a simple asymmetric rigid rotor Hamiltonian and show no evidence for spectral congestion due to intramolecular vibrational coupling, which bodes well for high resolution studies of other ring radicals and polycyclic aromatic hydrocarbons. In summary, the combination of slit jet discharge methods with high resolution infrared lasers enables spectroscopic investigation of even highly reactive combustion and interstellar radical intermediates under gas phase, jet-cooled (Trot ≈ 11 K) conditions.

10.
J Chem Phys ; 144(7): 074301, 2016 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-26896980

RESUMO

Infrared spectroscopy and formation dynamics of triacetylene are investigated in a slit jet supersonic discharge and probed with sub-Doppler resolution (≈60 MHz) on the fundamental antisymmetric CH stretch mode (ν5). The triacetylene is generated in the throat of the discharge by sequential attack of ethynyl radical with acetyelene and diacetylene: (i) HCCH → HCC + H, (ii) HCC + HCCH → HCCCCH + H, (iii) HCC + HCCCCH → HCCCCCCH + H, cooled rapidly in the slit expansion to 15 K, and probed by near shot-noise-limited absorption sensitivity with a tunable difference-frequency infrared laser. The combination of jet cooled temperatures (Trot = 15 K) and low spectral congestion permits (i) analysis of rotationally avoided crossings in the ν5 band ascribed to Coriolis interactions, as well as (ii) first detection of ν5 Π-Π hot band progressions built on the ν12 sym CC bend and definitively assigned via state-of-the-art ab initio vibration-rotation interaction parameters (αi), which make for interesting comparison with recent spectroscopic studies of Doney et al. [J. Mol. Spectrosc. 316, 54 (2015)]. The combined data provide direct evidence for significantly non-equilibrium populations in the CC bending manifold, dynamically consistent with a strongly bent radical intermediate and transition states for forming triacetylene product. The presence of intense triacetylene signals under cold, low density slit jet conditions provides support for (i) barrierless addition of HCC with HCCCCH and (ii) a high quantum yield for HCCCCCCH formation. Complete basis set calculations for energetics [CCSD(T)-f12/VnZ-f12, n = 2,3] and frequencies [CCSD(T)-f12/VdZ-f12] are presented for both radical intermediate and transition state species, predicting collision stabilization in the slit jet expansion to be competitive with unimolecular decomposition with increasing polyyne chain length.

11.
Nanotechnology ; 26(10): 105101, 2015 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-25693888

RESUMO

Benzo[a]pyrene (BaP), a component of cooking oil fumes (COF), promotes lung cancer cell proliferation and survival via the induction of inhibitor of apoptosis protein-2 (IAP-2) proteins. Thus knockdown of IAP-2 would be a promising way to battle against lung cancer caused by COF. Functionalized gold nanoparticle (AuNP) is an effective delivery system for bio-active materials. Here, biocompatible hyaluronic acid (HA) was fabricated into nanoparticles to increase the target specificity by binding to CD44-over-expressed cancer cells. IAP-2-specific small-interfering RNA (siRNAs) or fluorescein isothiocyanate (FITC) were then incorporated into AuNP-HA. Conjugation of IAP-2 siRNA into AuNPs-HA was verified by the UV-vis spectrometer and Fourier transform infrared spectrometer. Further studies showed that AuNP-HA/FITC were effectively taken up by A549 cells through CD44-mediated endocytosis. Incubation of BaP-challenged cells with AuNP-HA-IAP-2 siRNAs silenced the expression of IAP-2, decreased cell proliferation and triggered pronounced cell apoptosis by the decrease in Bcl-2 protein and the increase in Bax protein as well as the active form of caspases-3. The BaP-elicited cell migration and enzymatic activity of the secreted matrix metalloproteinase-2 were also substantially suppressed by treatment with AuNP-HA-IAP-2 siRNAs. These results indicated that IAP-2 siRNAs can be efficiently delivered into A549 cells by functionalized AuNP-HA to repress the IAP-2 expression and BaP-induced oncogenic events, suggesting the potential therapeutic application of IAP-2 siRNA or other siRNA-conjugated AuNP-HA composites to COF-induced lung cancer and other gene-caused diseases in the future.


Assuntos
Sistemas de Liberação de Medicamentos/instrumentação , Ouro/química , Ácido Hialurônico/química , Proteínas Inibidoras de Apoptose/uso terapêutico , Neoplasias Pulmonares/tratamento farmacológico , Nanopartículas/uso terapêutico , RNA Interferente Pequeno/uso terapêutico , Benzo(a)pireno/toxicidade , Materiais Biocompatíveis , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Humanos , Receptores de Hialuronatos , Proteínas Inibidoras de Apoptose/administração & dosagem , Neoplasias Pulmonares/induzido quimicamente , Nanopartículas/química , RNA Interferente Pequeno/administração & dosagem , Espécies Reativas de Oxigênio
12.
J Phys Chem A ; 119(28): 7940-50, 2015 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-25919691

RESUMO

Fundamental, bending (ν6, ν7, ν8, ν9), and CC-stretch (ν2, ν3) hot band spectra in the antisymmetric CH stretch (ν4) region near 3330 cm(-1) have been observed and analyzed for jet cooled diacetylene (HC≡C-C≡CH) under sub-Doppler conditions. Diacetylene is generated in situ in the throat of a pulsed supersonic slit expansion by discharge dissociation of acetylene to form ethynyl (C≡CH) + H, followed by radical attack (HC≡CH + C≡C-H) to form HC≡C-C≡CH + H. The combination of (i) sub-Doppler line widths and (ii) absence of spectral congestion permits rotational structure and Coriolis interactions in the ν4 CH stretch fundamental to be observed and analyzed with improved precision. Of particular dynamical interest, the spectra reveal diacteylene formation in highly excited internal vibrational states. Specifically, multiple Π â† Π and Δ â† Δ hot bands built on the ν4 CH stretch fundamental are observed, due to doubly degenerate bending vibrations [cis C≡C-H bend (ν6), trans C-C≡C bend (ν7), trans C≡C-H bend (ν8) and cis C-C≡C bend (ν9)], as well as a heretofore unobserved Σ â† Σ band assigned to excitation of ν2 or 2ν3 CC stretch. Boltzmann analysis yields populations consistent with universally cold rotations (Trot ≈ 15 ± 5 K) and yet superthermal vibrations (Tvib ≈ 85-430 K), the latter of which is quite anomalous for the high collision densities in a slit jet expansion. In order to elucidate the physical mechanism for this excess vibrational excitation, high level ab initio CCSD(T) calculations have been pursued with explicitly correlated basis sets (VnZ-f12; n = 2,3) and extrapolated to the complete basis set (CBS) limit using MOLPRO quantum chemistry software. The results suggest that the extensive hot band structure observed arises from (i) highly exothermic CCH + HCCH addition to yield a strongly bent HCCHCCH radical intermediate (ΔH = -62.6 kcal/mol), followed by (ii) rapid fragmentation over a submerged transition state barrier (ΔH = -18.9 kcal/mol) to form vibrationally hot diacetylene + H products (ΔH = -25.6 kcal/mol), and consistent with crossed molecular beam studies by Kaiser et al. [Phys. Chem. Chem. Phys. 2002, 4, 2950.] Finally, RRKM fragmentation rates for this complex are calculated, which exceed collision frequencies in the slit jet expansion and suggest near unity quantum efficiency for diacetylene formation.

13.
J Chem Phys ; 142(24): 244313, 2015 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-26133434

RESUMO

The acetylenic CH stretch mode (ν1) of propargyl (H2CCCH) radical has been studied at sub-Doppler resolution (∼60 MHz) via infrared laser absorption spectroscopy in a supersonic slit-jet discharge expansion, where low rotational temperatures (Trot = 13.5(4) K) and lack of spectral congestion permit improved determination of band origin and rotational constants for the excited state. For the lowest J states primarily populated in the slit jet cooled expansion, fine structure due to the unpaired electron spin is resolved completely, which permits accurate analysis of electron spin-rotation interactions in the vibrationally excited states (εaa = - 518.1(1.8), εbb = - 13.0(3), εcc = - 1.8(3) MHz). In addition, hyperfine broadening in substantial excess of the sub-Doppler experimental linewidths is observed due to nuclear spin-electron spin contributions at the methylenic (-CH2) and acetylenic (-CH) positions, which permits detailed modeling of the fine/hyperfine structure line contours. The results are consistent with a delocalized radical spin density extending over both methylenic and acetylenic C atoms, in excellent agreement with simple resonance structures as well as ab initio theoretical calculations.

14.
J Phys Chem A ; 117(39): 10047-57, 2013 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-23537501

RESUMO

Phenyl radical has been studied via sub-Doppler infrared spectroscopy in a slit supersonic discharge expansion source, with assignments for the highest frequency b2 out-of-phase C-H symmetric stretch vibration (ν19) unambiguously confirmed by ≤6 MHz (0.0002 cm(-1)) agreement with microwave ground state combination differences of McMahon et al. [Astrophys. J. 2003, 590, L61-64]. Least squares analysis of over 100 resolved rovibrational peaks in the sub-Doppler spectrum to a Watson Hamiltonian yields precision excited-state rotational constants and a vibrational band origin (ν0 = 3071.8915(4) cm(-1)) consistent with a surprisingly small red-shift (0.9 cm(-1)) with respect to Ar matrix isolation studies of Ellison and co-workers [J. Am. Chem. Soc. 2001, 123, 1977]. Nuclear spin weights and inertial defects confirm the vibrationally averaged planarity and (2)A1 rovibronic symmetry of phenyl radical, with analysis of the rotational constants consistent with a modest C2v distortion of the carbon backbone frame due to partial sp rehybridization of the σ C radical-center. Most importantly, despite the number of atoms (N = 11) and vibrational modes (3N - 6 = 27), phenyl radical exhibits a remarkably clean jet cooled high-resolution IR spectrum that shows no evidence of intramolecular vibrational relaxation (IVR) phenomena such as local or nonlocal perturbations due to strongly coupled nearby dark states. This provides strong support for the feasibility of high-resolution infrared spectroscopy in other aromatic hydrocarbon radical systems.

15.
J Phys Chem A ; 117(50): 13255-64, 2013 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-23701020

RESUMO

Rovibrational spectroscopy of the fundamental OH stretching mode of the trans-HOCO radical has been studied via sub-Doppler high-resolution infrared laser absorption in a discharge slit-jet expansion. The trans-HOCO radical is formed by discharge dissociation of H2O to form OH, which then combines with CO and cools in the Ne expansion to a rotational temperature of 13.0(6) K. Rigorous assignment of both a-type and b-type spectral transitions is made possible by two-line combination differences from microwave studies, with full rovibrational analysis of the spectrum based on a Watson asymmetric top Hamiltonian. Additionally, fine structure splittings of each line due to electron spin are completely resolved, thus permitting all three ε(aa), ε(bb), ε(cc) spin-rotation constants to be experimentally determined in the vibrationally excited state. Furthermore, as both a- and b-type transitions for trans-HOCO are observed for the first time, the ratio of transition dipole moment projections along the a and b principal axes is determined to be µ(a)/µ(b) = 1.78(5), which is in close agreement with density functional quantum theoretical predictions (B3LYP/6-311++g(3df,3pd), µ(a)/µ(b) = 1.85). Finally, we note the energetic possibility in the excited OH stretch state for predissociation dynamics (i.e., trans-HOCO → H + CO2), with the present sub-Doppler line widths providing a rigorous upper limit of >2.7 ns for the predissociation lifetime.

16.
J Alzheimers Dis Rep ; 7(1): 51-76, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36777330

RESUMO

Background: Alzheimer's disease (AD) is a multifactorial disorder characterized by cognitive decline. Current available therapeutics for AD have limited clinical benefit. Therefore, preventive therapies for interrupting the development of AD are critically needed. Molecules targeting multifunction to interact with various pathlogical components have been considered to improve the therapeutic efficiency of AD. In particular, herbal medicines with multiplicity of actions produce cognitive benefits on AD. Bugu-M is a multi-herbal extract composed of Ganoderma lucidum (Antler form), Nelumbo nucifera Gaertn., Ziziphus jujuba Mill., and Dimocarpus longan, with the ability of its various components to confer resilience to cognitive deficits. Objective: To evaluate the potential of Bugu-M on amyloid-ß (Aß) toxicity and its in vitro mechanisms and on in vivo cognitive function. Methods: We illustrated the effect of Bugu-M on Aß25-35-evoked toxicity as well as its possible mechanisms to diminish the pathogenesis of AD in rat cortical neurons. For cognitive function studies, 2-month-old female 3×Tg-AD mice were administered 400 mg/kg Bugu-M for 30 days. Behavioral tests were performed to assess the efficacy of Bugu-M on cognitive impairment. Results: In primary cortical neuronal cultures, Bugu-M mitigated Aß-evoked toxicity by reducing cytoskeletal aberrations and axonal disruption, restoring presynaptic and postsynaptic protein expression, suppressing mitochondrial damage and apoptotic signaling, and reserving neurogenic and neurotrophic factors. Importantly, 30-day administration of Bugu-M effectively prevented development of cognitive impairment in 3-month-old female 3×Tg-AD mice. Conclusion: Bugu-M might be beneficial in delaying the progression of AD, and thus warrants consideration for its preventive potential for AD.

17.
J Phys Chem A ; 116(25): 6750-8, 2012 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-22616733

RESUMO

The sensitivity of vibronic calculations to electronic structure methods and basis sets is explored and compared to accurate relative intensities of the vibrational bands of phenylacetylene in the S(1)(A(1)B(2)) ← S(0)(X(1)A(1)) transition. To provide a better measure of vibrational band intensities, the spectrum was recorded by cavity ringdown absorption spectroscopy up to energies of 2000 cm(-1) above the band origin in a slit jet sample. The sample rotational temperature was estimated to be about 30 K, but the vibrational temperature was higher, permitting the assignment of many vibrational hot bands. The vibronic structure of the electronic transition was simulated using a combination of time-dependent density functional theory (TD-DFT) electronic structure codes, Franck-Condon integral calculations, and a second-order vibronic model developed previously [Johnson, P. M.; Xu, H. F.; Sears, T. J. J. Chem. Phys. 2006, 125, 164331]. The density functional theory (DFT) functionals B3LYP, CAM-B3LYP, and LC-BLYP were explored. The long-range-corrected functionals, CAM-B3LYP and LC-BLYP, produced better values for the equilibrium geometry transition moment, but overemphasized the vibronic coupling for some normal modes, while B3LYP provided better-balanced vibronic coupling but a poor equilibrium transition moment. Enlarging the basis set made very little difference. The cavity ringdown measurements show that earlier intensities derived from resonance-enhanced multiphoton ionization (REMPI) spectra have relative intensity errors.

18.
Cells ; 11(12)2022 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-35740991

RESUMO

Chitosan (Chi) is a natural polymer that has been demonstrated to have potential as a promoter of neural regeneration. In this study, Chi was prepared with various amounts (25, 50, and 100 ppm) of gold (Au) nanoparticles for use in in vitro and in vivo assessments. Each as-prepared material was first characterized by UV-visible spectroscopy (UV-Vis), Fourier-transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), scanning electron microscopy (SEM), and Dynamic Light Scattering (DLS). Through the in vitro experiments, Chi combined with 50 ppm of Au nanoparticles demonstrated better biocompatibility. The platelet activation, monocyte conversion, and intracellular ROS generation was remarkably decreased by Chi-Au 50 pm treatment. Furthermore, Chi-Au 50 ppm could facilitate colony formation and strengthen matrix metalloproteinase (MMP) activation in mesenchymal stem cells (MSCs). The lower expression of CD44 in Chi-Au 50 ppm treatment demonstrated that the nanocomposites could enhance the MSCs undergoing differentiation. Chi-Au 50 ppm was discovered to significantly induce the expression of GFAP, ß-Tubulin, and nestin protein in MSCs for neural differentiation, which was verified by real-time PCR analysis and immunostaining assays. Additionally, a rat model involving subcutaneous implantation was used to evaluate the superior anti-inflammatory and endothelialization abilities of a Chi-Au 50 ppm treatment. Capsule formation and collagen deposition were decreased. The CD86 expression (M1 macrophage polarization) and leukocyte filtration (CD45) were remarkably reduced as well. In summary, a Chi polymer combined with 50 ppm of Au nanoparticles was proven to enhance the neural differentiation of MSCs and showed potential as a biosafe nanomaterial for neural tissue engineering.


Assuntos
Quitosana , Células-Tronco Mesenquimais , Nanopartículas Metálicas , Nanocompostos , Animais , Quitosana/química , Quitosana/farmacologia , Ouro/química , Ouro/farmacologia , Nanopartículas Metálicas/química , Nanocompostos/química , Ratos
19.
Cells ; 11(14)2022 07 11.
Artigo em Inglês | MEDLINE | ID: mdl-35883615

RESUMO

n-butylidenephthalide (BP) has been verified as having the superior characteristic of cancer cell toxicity. Furthermore, gold (Au) nanoparticles are biocompatible materials, as well as effective carriers for delivering bio-active molecules for cancer therapeutics. In the present research, Au nanoparticles were first conjugated with polyethylene glycol (PEG), and then cross-linked with BP to obtain PEG-Au-BP nanodrugs. The physicochemical properties were characterized through ultraviolet-visible spectroscopy (UV-Vis), Fourier-transform infrared spectroscopy (FTIR), and dynamic light scattering (DLS) to confirm the combination of PEG, Au, and BP. In addition, both the size and structure of Au nanoparticles were observed through scanning electron microscopy (SEM) and transmission electron microscopy (TEM), where the size of Au corresponded to the results of DLS assay. Through in vitro assessments, non-transformed BAEC and DBTRG human glioma cells were treated with PEG-Au-BP drugs to investigate the tumor-cell selective cytotoxicity, cell uptake efficiency, and mechanism of endocytic routes. According to the results of MTT assay, PEG-Au-BP was able to significantly inhibit DBTRG brain cancer cell proliferation. Additionally, cell uptake efficiency and potential cellular transportation in both BAEC and DBTRG cell lines were observed to be significantly higher at 2 and 24 h. Moreover, the mechanisms of endocytosis, clathrin-mediated endocytosis, and cell autophagy were explored and determined to be favorable routes for BAEC and DBTRG cells to absorb PEG-Au-BP nanodrugs. Next, the cell progression and apoptosis of DBTRG cells after PEG-Au-BP treatment was investigated by flow cytometry. The results show that PEG-Au-BP could remarkably regulate the DBTRG cell cycle at the Sub-G1 phase, as well as induce more apoptotic cells. The expression of apoptotic-related proteins in DBTRG cells was determined through Western blotting assay. After treatment with PEG-Au-BP, the apoptotic cascade proteins p21, Bax, and Act-caspase-3 were all significantly expressed in DBTRG brain cancer cells. Through in vivo assessments, the tissue morphology and particle distribution in a mouse model were examined after a retro-orbital sinus injection containing PEG-Au-BP nanodrugs. The results demonstrate tissue integrity in the brain (forebrain, cerebellum, and midbrain), heart, liver, spleen, lung, and kidney, as they did not show significant destruction due to PEG-Au-BP treatment. Simultaneously, the extended retention period for PEG-Au-BP nanodrugs was discovered, particularly in brain tissue. The above findings identify PEG-Au-BP as a potential nanodrug for brain cancer therapies.


Assuntos
Neoplasias Encefálicas , Nanopartículas Metálicas , Animais , Proteínas Reguladoras de Apoptose/uso terapêutico , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/patologia , Linhagem Celular Tumoral , Ouro/química , Ouro/farmacologia , Humanos , Nanopartículas Metálicas/química , Camundongos , Anidridos Ftálicos , Polietilenoglicóis/química
20.
Nat Commun ; 13(1): 2518, 2022 05 06.
Artigo em Inglês | MEDLINE | ID: mdl-35523813

RESUMO

The nervous and endocrine systems coordinate with each other to closely influence physiological and behavioural responses in animals. Here we show that WAKE (encoded by wide awake, also known as wake) modulates membrane levels of GABAA receptor Resistance to Dieldrin (Rdl), in insulin-producing cells of adult male Drosophila melanogaster. This results in changes to secretion of insulin-like peptides which is associated with changes in juvenile hormone biosynthesis in the corpus allatum, which in turn leads to a decrease in 20-hydroxyecdysone levels. A reduction in ecdysone signalling changes neural architecture and lowers the perception of the male-specific sex pheromone 11-cis-vaccenyl acetate by odorant receptor 67d olfactory neurons. These finding explain why WAKE-deficient in Drosophila elicits significant male-male courtship behaviour.


Assuntos
Proteínas de Drosophila , Insulinas , Acetatos , Animais , Corte , Drosophila/metabolismo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Sistema Endócrino/metabolismo , Masculino , Percepção , Feromônios , Receptores de GABA-A , Comportamento Sexual Animal/fisiologia
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