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1.
Proc Natl Acad Sci U S A ; 119(40): e2203783119, 2022 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-36161901

RESUMO

ASPM is a protein encoded by primary microcephaly 5 (MCPH5) and is responsible for ensuring spindle position during mitosis and the symmetrical division of neural stem cells. We recently reported that ASPM promotes homologous recombination (HR) repair of DNA double strand breaks. However, its potential role in DNA replication and replication stress response remains elusive. Interestingly, we found that ASPM is dispensable for DNA replication under unperturbed conditions. However, ASPM is enriched at stalled replication forks in a RAD17-dependent manner in response to replication stress and promotes RAD9 and TopBP1 loading onto chromatin, facilitating ATR-CHK1 activation. ASPM depletion results in failed fork restart and nuclease MRE11-mediated nascent DNA degradation at the stalled replication fork. The overall consequence is chromosome instability and the sensitization of cancer cells to replication stressors. These data support a role for ASPM in loading RAD17-RAD9/TopBP1 onto chromatin to activate the ATR-CHK1 checkpoint and ultimately ensure genome stability.


Assuntos
Proteínas Mutadas de Ataxia Telangiectasia , Quinase 1 do Ponto de Checagem , Replicação do DNA , Proteínas do Tecido Nervoso , Animais , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Proteínas de Transporte/metabolismo , Proteínas de Ciclo Celular/metabolismo , Quinase 1 do Ponto de Checagem/genética , Quinase 1 do Ponto de Checagem/metabolismo , Cromatina/genética , Reparo do DNA/genética , Replicação do DNA/genética , Proteínas de Ligação a DNA/metabolismo , Células HeLa , Humanos , Camundongos , Microcefalia/genética , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/fisiologia , Proteínas Nucleares/metabolismo
2.
Crit Rev Biochem Mol Biol ; 57(3): 333-350, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35112600

RESUMO

Cohesin, a four-subunit ring comprising SMC1, SMC3, RAD21 and SA1/2, tethers sister chromatids by DNA replication-coupled cohesion (RC-cohesion) to guarantee correct chromosome segregation during cell proliferation. Postreplicative cohesion, also called damage-induced cohesion (DI-cohesion), is an emerging critical player in DNA damage response (DDR). In this review, we sum up recent progress on how cohesin regulates the DNA damage checkpoint activation and repair pathway choice, emphasizing postreplicative cohesin loading and DI-cohesion establishment in yeasts and mammals. DI-cohesion and RC-cohesion show distinct features in many aspects. DI-cohesion near or far from the break sites might undergo different regulations and execute different tasks in DDR and DSB repair. Furthermore, some open questions in this field and the significance of this new scenario to our understanding of genome stability maintenance and cohesinopathies are discussed.


Assuntos
Proteínas Cromossômicas não Histona , Proteínas Nucleares , Animais , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Proteínas Cromossômicas não Histona/genética , Proteínas Cromossômicas não Histona/metabolismo , Dano ao DNA , Reparo do DNA , Mamíferos/metabolismo , Proteínas Nucleares/genética , Coesinas
3.
Anal Chem ; 96(15): 6072-6078, 2024 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-38577757

RESUMO

The urgent need for sensitive and accurate assays to monitor acetylcholinesterase (AChE) activity and organophosphorus pesticides (OPs) arises from the imperative to safeguard human health and protect the ecosystem. Due to its cost-effectiveness, ease of operation, and rapid response, nanozyme-based colorimetry has been widely utilized in the determination of AChE activity and OPs. However, the rational design of nanozymes with high activity and specificity remains a great challenge. Herein, trace amount of Bi-doped core-shell Pd@Pt mesoporous nanospheres (Pd@PtBi2) have been successfully synthesized, exhibiting good peroxidase-like activity and specificity. With the incorporation of trace bismuth, there is a more than 4-fold enhancement in the peroxidase-like performance of Pd@PtBi2 compared to that of Pd@Pt. Besides, no significant improvement of oxidase-like and catalase-like activities of Pd@PtBi2 was found, which prevents interference from O2 and undesirable consumption of substrate H2O2. Based on the blocking impact of thiocholine, a colorimetric detection platform utilizing Pd@PtBi2 was constructed to monitor AChE activity with sensitivity and selectivity. Given the inhibition of OPs on AChE activity, a biosensor was further developed by integrating Pd@PtBi2 with AChE to detect OPs, capitalizing on the cascade amplification strategy. The OP biosensor achieved a detection limit as low as 0.06 ng mL-1, exhibiting high sensitivity and anti-interference ability. This work is promising for the construction of nanozymes with high activity and specificity, as well as the development of nanozyme-based colorimetric biosensors.


Assuntos
Técnicas Biossensoriais , Nanosferas , Agentes Neurotóxicos , Praguicidas , Humanos , Acetilcolinesterase/metabolismo , Compostos Organofosforados , Praguicidas/análise , Peróxido de Hidrogênio , Ecossistema , Oxirredutases , Peroxidase , Colorimetria
4.
Cell Commun Signal ; 22(1): 108, 2024 02 12.
Artigo em Inglês | MEDLINE | ID: mdl-38347543

RESUMO

Psoriasis is an immune-mediated inflammatory skin disease, involving a complex interplay between genetic and environmental factors. Previous studies have demonstrated that genetic factors play a major role in the pathogenesis of psoriasis. However, non-genetic factors are also necessary to trigger the onset and recurrence of psoriasis in genetically predisposed individuals, which include infections, microbiota dysbiosis of the skin and gut, dysregulated lipid metabolism, dysregulated sex hormones, and mental illness. Psoriasis can also be induced by other environmental triggers, such as skin trauma, unhealthy lifestyles, and medications. Understanding how these triggers play a role in the onset and recurrence of psoriasis provides insights into psoriasis pathogenesis, as well as better clinical administration. In this review, we summarize the triggers for the onset and recurrence of psoriasis and update the current evidence on the underlying mechanism of how these factors elicit the disease. Video Abstract.


Assuntos
Microbiota , Psoríase , Humanos , Psoríase/genética , Pele/patologia
5.
Dermatology ; 240(1): 95-102, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-37848012

RESUMO

BACKGROUND: Rosacea is a chronic inflammatory dermatological condition in humans, and its pathogenesis remains unclear. However, the development of rosacea is suspected to be related to Demodex, a microscopic commensal organism that resides in or near hair follicles and sebaceous glands. Although Demodex is known to be a host-specific, obligate commensal organism, it is currently difficult to be cultured in vitro to parasitize and infect other animal hosts. Therefore, direct evidence for a pathogenic role of Demodex in rosacea is currently lacking. SUMMARY: As circumstantial evidence, non-invasive skin-detecting techniques have shown abnormally elevated numbers of Demodex in rosacea patients. Increased cytokine levels such as IL-10, IL-8, and IL-12p70 have been observed in human sebocytes following the Demodex challenge, and acaricides have been found to be effective in rosacea therapy, all point to a close relationship between Demodex and rosacea. Based on these findings, we conducted a comprehensive literature review to summarize the current state of knowledge, research insights, and clinical treatment recommendations for Demodex-associated rosacea, with the ultimate goal of improving patient outcomes.


Assuntos
Infestações por Ácaros , Ácaros , Rosácea , Animais , Humanos , Infestações por Ácaros/complicações , Infestações por Ácaros/patologia , Rosácea/complicações , Pele/patologia , Glândulas Sebáceas/patologia
6.
Sichuan Da Xue Xue Bao Yi Xue Ban ; 55(2): 353-359, 2024 Mar 20.
Artigo em Zh | MEDLINE | ID: mdl-38645852

RESUMO

Objective: To investigate the longitudinal association between alcohol abstinence and accelerated biological aging among middle-aged and older adults and to explore the potential effect modifiers influencing the association. Methods: Utilizing the clinico-biochemical and anthropometric data from the baseline and first repeat survey of the UK Biobank (UKB), we employed the Klemera and Doubal method (KDM) to construct the biological age (BA) and calculate BA acceleration. Change analysis based on multivariate linear regression models was employed to explore the association between changes in alcohol abstinence and changes in BA acceleration. Age, sex, smoking status, tea and coffee consumption, and body mass index were considered as the stratification factors for conducting stratified analysis. Results: A total of 5 412 participants were included. Short-term alcohol abstinence (ß=1.00, 95% confidence interval [CI]: 0.15-1.86) was found to accelerate biological aging when compared to consistent never drinking, while long-term abstinence (ß=-0.20, 95% CI: -1.12-0.71) did not result in a significant acceleration of biological aging. Body mass index may be a potential effect modifier. Conclusion: Short-term alcohol abstinence was associated with accelerated biological aging, but the effect gradually diminishes over extended periods of abstinence.


Assuntos
Abstinência de Álcool , Consumo de Bebidas Alcoólicas , Índice de Massa Corporal , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Envelhecimento/fisiologia , Modelos Lineares , Estudos Longitudinais , Biobanco do Reino Unido , Reino Unido
7.
Biochem Biophys Res Commun ; 667: 146-152, 2023 07 30.
Artigo em Inglês | MEDLINE | ID: mdl-37229823

RESUMO

BACKGROUND: Acne is associated with the excessive production of sebum, a complex mixture of lipids, in the sebaceous glands. The transcription factor Krüppel-like factor 4 (KLF4) plays an important role in skin morphogenesis, but its role in sebum production by sebocytes is not well known. PURPOSE: In this study, we investigated the possible action mechanism of KLF4 during calcium-induced lipogenesis in immortalized human sebocytes. METHODS: Sebocytes were treated with calcium, and lipid production was confirmed by thin-layer chromatography (TLC) and Oil Red O staining. To investigate the effect of KLF4, sebocytes were transduced with the KLF4-overexpressing adenovirus, and then lipid production was evaluated. RESULTS: Calcium treatment resulted in increased sebum production in terms of squalene synthesis in sebocytes. In addition, calcium increased the expression of lipogenic regulators such as sterol-regulatory element binding protein 1 (SREBP1), sterol-regulatory element binding protein 2 (SREBP2), and stearoyl-CoA desaturase (SCD). Similarly, the expression of KLF4 was increased by calcium in sebocytes. To investigate the effect of KLF4, we overexpressed KLF4 in sebocytes using recombinant adenovirus. As a result, KLF4 overexpression increased the expression of SREBP1, SREBP2, and SCD. Parallel to this result, lipid production was also increased by KLF4 overexpression. Chromatin immunoprecipitation revealed the binding of KLF4 to the SREBP1 promoter, indicating that KLF4 may directly regulate the expression of lipogenic regulators. CONCLUSION: These results suggest that KLF4 is a novel regulator of lipid production in sebocytes.


Assuntos
Cálcio , Fator 4 Semelhante a Kruppel , Humanos , Cálcio/metabolismo , Células Cultivadas , Lipídeos , Lipogênese , Glândulas Sebáceas/metabolismo , Estearoil-CoA Dessaturase/genética , Estearoil-CoA Dessaturase/metabolismo , Esteróis/metabolismo
8.
Macromol Rapid Commun ; 44(6): e2200829, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36482796

RESUMO

The development of multifunctional supramolecular hydrogels with high mechanical strength and multifunction is in high demand. In this work, the diblock copolymer poly(acrylamide-co-1-benzyl-3-vinylimidazolium bromide)-block-polyAzobenzene is synthesized through reversible addition-fragmentation chain transfer polymerization. The dynamic host-guest interactions between the host molecule cucurbit[8] uril and guest units are used to fabricate a 3D network of supramolecular hydrogels. Investigations on the properties of the supramolecular hydrogels show that the tensile stress of the sample is 1.46 MPa, eight times higher than that of hydrogel without liquid-crystalline block copolymer, and the self-healing efficiency of the supramolecular hydrogels at room temperature is 88.3% (fracture stress) and 100% (fracture strain) after 24 h. Results show that microphase-separated structure plays a key role in the high-strength hydrogel, whereas the host-guest interaction endows the hydrogel with self-healing properties. The supramolecular hydrogels with high mechanical strength, photo-responsivity, injectability, and biocompatibility can be used in various potential applications.


Assuntos
Hidrogéis , Polímeros , Hidrogéis/química , Polímeros/química
9.
Int J Med Sci ; 20(9): 1220-1234, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37575275

RESUMO

Purpose: Melanoma is a highly malignant tumor, which metastasizes and has poor prognosis in late-stage cancer patients. α-Mangostin possesses pharmacological properties, including antioxidant, anti-infective, and anticarcinogenic activities. We investigated α-Mangostin effect on melanoma growth, migration, and invasion and its possible molecular mechanism. Methods: Melanoma cells growth inhibition was determined by the colorimetric 4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide reduction assay. Morphological changes of α-Mangostin-treated melanoma cells were evaluated by transmission electron microscopy and JC-1 staining. Cell apoptosis and cell cycle arrest were assessed by flow cytometry. The effect of α-Mangostin on tumor cells migration and invasion was observed by migration and invasion in vitro assay. Furthermore, the nude and C57BL/6 mouse subcutaneous melanoma models were used to evaluate the in vivo anti-tumor effect of α-Mangostin. Western blot and real time-PCR were performed to analyze the influence of α-Mangostin on some of the common signaling pathways in melanoma cell lines. Signaling pathways were further verified in dissected tumor tissues. Results: α-Mangostin inhibited in vitro melanoma cells proliferation, migration, and invasion of melanoma cells, induced cell cycle arrest in G0/G1 phase, and caused mitochondrial swelling and membrane depolarization, whereas it effectively suppressed melanoma growth in xenografted mice. In addition, α-Mangostin potentiated the in vitro and in vivo anti-tumor effects of cisplatin both in vitro and in vivo. Mechanistically, α-Mangostin down-regulated expression of RAS protein and mRNA, as well as phosphorylation of PI3K in A375, B16F10, M14 and SK-MEL-2 cells. MITF protein and mRNA were inhibited only in M14 cells. Conclusion: α-Mangostin suppresses melanoma cells growth, migration and invasion, and synergistically enhances the anti-tumor effect of chemotherapy, whose mechanism may be mediated through inhibiting Ras, PI3K and MITF.


Assuntos
Melanoma , Animais , Camundongos , Linhagem Celular Tumoral , Camundongos Endogâmicos C57BL , Melanoma/tratamento farmacológico , Proliferação de Células , Apoptose , RNA Mensageiro , Fosfatidilinositol 3-Quinases/genética , Fosfatidilinositol 3-Quinases/metabolismo , Movimento Celular
10.
Zhongguo Dang Dai Er Ke Za Zhi ; 24(1): 33-40, 2022 Jan 15.
Artigo em Inglês, Zh | MEDLINE | ID: mdl-35177173

RESUMO

OBJECTIVES: To investigate the clinical treatment outcomes and the changes of the outcomes over time in extremely preterm twins in Guangdong Province, China. METHODS: A retrospective analysis was performed for 269 pairs of extremely preterm twins with a gestational age of <28 weeks who were admitted to the department of neonatology in 26 grade A tertiary hospitals in Guangdong Province from January 2008 to December 2017. According to the admission time, they were divided into two groups: 2008-2012 and 2013-2017. Besides, each pair of twins was divided into the heavier infant and the lighter infant subgroups according to birth weight. The perinatal data of mothers and hospitalization data of neonates were collected. The survival rate of twins and the incidence rate of complications were compared between the 2008-2012 and 2013-2017 groups. RESULTS: Compared with the 2008-2012 group, the 2013-2017 group (both the heavier infant and lighter infant subgroups) had lower incidence rates of severe asphyxia and smaller head circumference at birth (P<0.05). The mortality rates of both of the twins, the heavier infant of the twins, and the lighter infant of the twins were lower in the 2013-2017 group compared with the 2008-2012 group (P<0.05). Compared with the 2008-2012 group, the 2013-2017 group (both the heavier infant and lighter infant subgroups) had lower incidence rates of pulmonary hemorrhage, patent ductus arteriosus (PDA), periventricular-intraventricular hemorrhage (P-IVH), and neonatal respiratory distress syndrome (NRDS) and a higher incidence rate of bronchopulmonary dysplasia (P<0.05). CONCLUSIONS: There is a significant increase in the survival rate over time in extremely preterm twins with a gestational age of <28 weeks in the 26 grade A tertiary hospitals in Guangdong Province. The incidences of severe asphyxia, pulmonary hemorrhage, PDA, P-IVH, and NRDS decrease in both the heavier and lighter infants of the twins, but the incidence of bronchopulmonary dysplasia increases. With the improvement of diagnosis and treatment, the multidisciplinary collaboration between different fields of fetal medicine including prenatal diagnosis, obstetrics, and neonatology is needed in the future to jointly develop management strategies for twin pregnancy.


Assuntos
Displasia Broncopulmonar , Síndrome do Desconforto Respiratório do Recém-Nascido , Displasia Broncopulmonar/epidemiologia , Feminino , Idade Gestacional , Humanos , Lactente , Lactente Extremamente Prematuro , Recém-Nascido , Gravidez , Síndrome do Desconforto Respiratório do Recém-Nascido/epidemiologia , Estudos Retrospectivos , Resultado do Tratamento
11.
J Am Chem Soc ; 143(27): 10309-10316, 2021 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-34196529

RESUMO

Balancing the second-harmonic generation (SHG) coefficient, band gap, and birefringence is a vital but addressable challenge for designing infrared nonlinear optical materials. By applying a "rigidity-flexibility coupling" strategy, a quaternary diamond-like phosphide, Mg2In3Si2P7, with wurtzite-type superstructure was successfully designed and synthesized. Remarkably, it achieved the rare coexistence of giant second-harmonic generation (2 × ZnGeP2 and 7.1 × AgGaS2), suitable band gap (2.21 eV), moderate birefringence (0.107), and wide IR transparent range (0.56-16.4 µm). First-principles calculations revealed that the giant SHG response and large birefringence can be attributed to the synergy of arrangement-aligned [InP4] and [SiP4] tetrahedra. This work not only opens a new avenue for designing advanced infrared nonlinear optical materials but also may spur more explorations on quaternary diamond-like pnictides.

12.
Mycoses ; 64(12): 1527-1534, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33978260

RESUMO

BACKGROUND: Tinea capitis is a common dermatophyte infection of the scalp primarily affecting children, with less frequent, though not rare, observation in adults. OBJECTIVE: This study aimed to assess changes in the causative agents of adult tinea capitis over a 60-year period in the Hubei area. METHODS: A retrospective, single-centre study was performed on 164 adults with tinea capitis between 1960 and 2020. RESULTS: Out of 1113 cases of tinea capitis, 164 patients were adults, representing 14.7% of all patients. Adult tinea capitis was slightly more prevalent in males (91, 55.5%) than in females (73, 44.5%), but gender difference was not statistically significant between adults and children. Adult tinea capitis was most prevalent between the ages of 18 and 29 years, with a mean age of 22 years. Trichophyton schoenleinii was the most common dermatophyte in adult tinea capitis (78, 47.6%), followed by Trichophyton violaceum (58, 35.4%). Most adult tinea capitis cases before the 1980s were caused by T. schoenleinii, but T. violaceum has become the leading pathogen for recent adult tinea capitis cases. CONCLUSION: Tinea capitis is not a disease exclusive to children. On the contrary, an upward trend of tinea capitis in adults has been observed in recent years. T. violaceum has become the dominant causative agent of adult tinea capitis in the Hubei area, replacing T. schoenleinii. These results provide a better understanding of the treatment and prevention of tinea capitis in adults.


Assuntos
Tinha do Couro Cabeludo , Trichophyton/classificação , Adolescente , Adulto , China/epidemiologia , Feminino , Humanos , Masculino , Estudos Retrospectivos , Couro Cabeludo , Tinha do Couro Cabeludo/epidemiologia , Tinha do Couro Cabeludo/microbiologia , Adulto Jovem
13.
Entropy (Basel) ; 23(11)2021 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-34828205

RESUMO

Deep convolutional neural networks (DCNNs) have achieved breakthrough performance on bird species identification using a spectrogram of bird vocalization. Aiming at the imbalance of the bird vocalization dataset, a single feature identification model (SFIM) with residual blocks and modified, weighted, cross-entropy function was proposed. To further improve the identification accuracy, two multi-channel fusion methods were built with three SFIMs. One of these fused the outputs of the feature extraction parts of three SFIMs (feature fusion mode), the other fused the outputs of the classifiers of three SFIMs (result fusion mode). The SFIMs were trained with three different kinds of spectrograms, which were calculated through short-time Fourier transform, mel-frequency cepstrum transform and chirplet transform, respectively. To overcome the shortage of the huge number of trainable model parameters, transfer learning was used in the multi-channel models. Using our own vocalization dataset as a sample set, it is found that the result fusion mode model outperforms the other proposed models, the best mean average precision (MAP) reaches 0.914. Choosing three durations of spectrograms, 100 ms, 300 ms and 500 ms for comparison, the results reveal that the 300 ms duration is the best for our own dataset. The duration is suggested to be determined based on the duration distribution of bird syllables. As for the performance with the training dataset of BirdCLEF2019, the highest classification mean average precision (cmAP) reached 0.135, which means the proposed model has certain generalization ability.

14.
Can J Infect Dis Med Microbiol ; 2021: 7865405, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34093925

RESUMO

Neisseria gonorrhoeae (N. gonorrhoeae, gonococci, or GC), the etiologic agent of gonorrhea, is a human-obligate bacterial pathogen. The GC surface contains pili that mediate the adherence to host cells. Studies have shown that GC pili, coded by pilin genes, undergo remarkable changes during human experimental gonorrhea, possibly generated by DNA phase variation during infection. The question that arises is whether the changes in pilins can alter the adherence capacity of N. gonorrhoeae to host cells. In this study, six variants initially isolated from male volunteers infected with one single clone of GC were examined for their adherence patterns with human Chang conjunctiva cells. In this study, we showed that the variants showed distinct adherence patterns to this cell line under light microscopy and scanning electron microscopy. Moreover, two reisolates showed higher adherence capacities than that of the input strain. The results provide an additional example as to how the pilus variation may play a role in the pathogenesis of N. gonorrhoeae.

15.
Microb Pathog ; 141: 103993, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31988008

RESUMO

Yersinia pestis, a Gram-negative bacterium, is the etiologic agent of plague. A hallmark of Y. pestis infection is the organism's ability to rapidly disseminate through an animal host. Y. pestis expresses the outer membrane protein, Ail (Attachment invasion locus), which is associated with host invasion and serum resistance. However, whether Ail plays a role in host dissemination remains unclear. In this study, C57BL/6J mice were challenged with a defined Y. pestis strain, KimD27, or an isogenic ail-deleted mutant derived from KimD27 via metacarpal paw pad inoculation, nasal drops, orogastric infection, or tail vein injection to mimic bubonic, pneumonic, oral, or septicemic plague, respectively. Our results showed that ail-deleted Y. pestis KimD27 lost the ability to invade host cells, leading to failed host dissemination in the pneumonic and oral plague models but not in the bubonic or septicemic plague models, which do not require invasiveness. Therefore, this study demonstrated that whether Ail plays a role in Y. pestis pathogenesis depends on the infection route.


Assuntos
Proteínas da Membrana Bacteriana Externa/metabolismo , Peste/microbiologia , Fatores de Virulência/metabolismo , Virulência , Yersinia pestis , Animais , Proteínas de Bactérias/metabolismo , Modelos Animais de Doenças , Pulmão/microbiologia , Camundongos , Camundongos Endogâmicos C57BL , Boca/microbiologia , Yersinia pestis/metabolismo , Yersinia pestis/patogenicidade
16.
Langmuir ; 36(2): 600-608, 2020 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-31885276

RESUMO

Because of the unique optical properties of gold nanomaterials, the preparation of gold nanomaterials with excellent chirality has received extensive attention. In order to develop a simple fabrication method for three-dimensional chiral Au nanostructures with a size of several hundred nanometers, chiral gold nanoparticles were developed to transfer chirality of a peptide to gold nanoparticles. In this study, the controlled synthesis of asymmetric gold nanopolyhedrons was achieved. The asymmetric gold nanopolyhedrons prepared via peptide-directed growth can exhibit strong circular dichroism (∼±50 mdeg) couplets in the visible range (500-600 nm). Also, the morphology of chiral Au nanododecahedrons-peptide particles showed distorted and asymmetric properties. In order to prove that the size and spatial structure of gold nanopolyhedrons have an influence on their chiral optical properties, Au nanotrioctahedron-peptide particles were prepared by using Au nanotrioctahedrons with different morphologies. Au nanotrioctahedron-peptide particles also exhibited circular dichromatic couplets in the visible region.


Assuntos
Ouro/química , Nanopartículas Metálicas/química , Peptídeos/síntese química , Fenômenos Ópticos , Tamanho da Partícula , Peptídeos/química , Propriedades de Superfície
17.
Soft Matter ; 16(14): 3416-3424, 2020 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-32219229

RESUMO

The introduction of structured microsphere composites into hydrogels is found to improve their mechanical strength capability. Herein, chitosan microspheres were functionalized with poly(acrylamide-co-1-benzyl-3-vinylimidazolium bromide) (CS-P(AM-G)), which was synthesized through an in situ copolymerization of acrylamide and a guest functional monomer. Supramolecular hydrogels were fabricated by dynamic host-guest interactions between guest units and the host molecule cucurbit[8]uril (CB[8]). Investigations on the mechanical properties of the hydrogels show that the tensile stress and the compress stress of the hydrogels are five times higher than those of CB[8] hydrogels without CS, and the healing efficiency of the hydrogels at room temperature is 88% after 24 h. The results show that CS microspheres serve as both polyfunctional initiating and cross-linking centers, whereas the dynamic host-guest interactions endow the hydrogels with a higher self-healing property. The process provides a novel method for the production of tough and self-healing supramolecular hydrogels with various potential applications.

18.
Langmuir ; 35(38): 12501-12508, 2019 09 24.
Artigo em Inglês | MEDLINE | ID: mdl-31503496

RESUMO

Vesicular structures of block copolymers and inorganic nanoparticles with good stability have potential applications in therapeutic drug release and bioimaging. Herein, a block copolymer of polystyrene-b-poly(acrylic acid) (PS48-b-PAA67) and water-soluble AgInS2/ZnS core/shell quantum dots (QDs) capped with gelatin and thioglycolic acid were coassembled in tetrahydrofuran by adding water. The positively charged QDs bind to negatively charged PAA segments through electrostatic interaction. Numerous vesicular structures, such as uniform bilayer vesicles, flowerlike large compound vesicles, onionlike lamellar structures consisting of alternating PS and PAA&QD layers, and multilamellar vesicles with spaces between concentric vesicle layers were obtained from the coassembly of PS48-b-PAA67 with QDs. The binding of the positively charged QDs to the PAA block influenced both the intra-aggregate PAA corona conformation and the interaggregate interactions. The key parameters affecting the formation of these vesicular structures included the QD content, solution pH, and water addition rate. Thus, tunable vesicular structures can be prepared and regulated through this simple but effective coassembly method.

19.
Inorg Chem ; 58(11): 7564-7570, 2019 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-31117632

RESUMO

Here, we report the crystal structures and properties of Rb xNbSe2, with 0 ≤ x ≤ 0.5. With Rb intercalation, Rb xNbSe2 evolves from 2H (Phase I) for 0 ≤ x ≤ 0.025, to 6R (Phase II) for x ∼ 0.2 with space group R3 m (no. 166), and finally to 2H (Phase IV) for 0.375 ≤ x ≤ 0.5 with space group P63/ mmc (no. 194). In addition, Phase II is found to transform to a rare 6H structure (Phase III) with space group P63/ mmc (no. 194) by annealing at a relatively low temperature. We show the first 6H phase in the intercalated transition-metal dichalcogenides (TMDs) family obtained through a solid-state reaction. Moreover, both 6R and 6H phases are new polymorphs in the NbSe2 system. For the range 0.2 ≤ x ≤ 0.5 in Rb xNbSe2, we show metallic electronic transport behavior and a paramagnetic feature. The lack of superconductivity (SC) down to 2 K is most probably due to the decrease of hole carrier density with increasing Rb content. Through careful analysis of the structural data, we were able to assemble a phase diagram covering the range of 0 ≤ x ≤ 0.5 in Rb xNbSe2.

20.
Med Sci Monit ; 25: 6990-6997, 2019 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-31527570

RESUMO

BACKGROUND We studied the effect of APOBEC3G on persistent human papillomavirus (HPV) infection and the correlation between APOBEC3G polymorphism and HPV persistent infection and cervical disease progression in Uygur women in China. MATERIAL AND METHODS From January 2015 to December 2017, we enrolled 529 Uygur ethnic group patients with HPV infection. SIHA cells were transfected with APOBEC3G. Real-time quantitative polymerase chain reaction (RT-qPCR) and Western blot analysis were used to detect mRNA and protein expression levels of APOBEC3G and HPV E6 and p53. Exon 3 of APOBEC3G was sequenced by first-generation sequencing. RESULTS The mRNA and protein expression levels of APOBEC3G in the cervical cancer group were significantly higher than in the cervical intraepithelial neoplasia (CIN) group (p<0.05). The mRNA and protein expression levels of APOBEC3G in the CIN group were significantly higher than in the non-cervical lesions group (p<0.05). The mRNA and protein expression levels of HPV E6 in SIHA cells transfected with APOBEC3G were significantly lower than in the control group and the no-load group (p<0.05), and the mRNA and protein expression levels of p53 were significantly higher than in the control group and the no-load group (p<0.05). There was a polymorphic locus rs5757465 on exon 3 of APOBEC3G in Uygur women, and this rare CC type was a risk factor for cervical lesions and cervical cancer (OR=3.714, 95%CI: 1.916-7.202, p<0.05). CONCLUSIONS APOBEC3G is involved in continuous HPV infection, cervical prelesions, and the development of cervical cancer, and the rare genotype (CC) of APOBEC3G may be one of the factors causing cervical lesions in Uygur women who have HPV infection.


Assuntos
Desaminase APOBEC-3G/genética , Progressão da Doença , Predisposição Genética para Doença , Infecções por Papillomavirus/genética , Polimorfismo de Nucleotídeo Único/genética , Neoplasias do Colo do Útero/genética , Neoplasias do Colo do Útero/virologia , Alelos , Sequência de Bases , Éxons/genética , Feminino , Regulação Neoplásica da Expressão Gênica , Loci Gênicos , Humanos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Neoplasias do Colo do Útero/patologia
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