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1.
Ecotoxicol Environ Saf ; 257: 114957, 2023 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-37105099

RESUMO

The spike is the organ that contributes the most to lead (Pb) accumulation in wheat grains. However, as an important photosynthetic and transpiration tissue in spike, the role of awn in wheat grain Pb absorption remains unknown. A field experiment was conducted to investigate the influence mechanism of awn on grain Pb accumulation through two comparative treatments: with and without awns (de-awned treatment). The de-awned treatment decreased wheat yield by 4.1 %; however, it significantly lowered the grain Pb accumulation rate at the late filling stage (15 days after anthesis) and led to a 22.8 % decrease in grain Pb concentration from 0.57 to 0.44 mg·kg-1. Moreover, the relative contribution of awn-to-grain Pb accumulation gradually increased with the filling process, finally reaching 26.6 % at maturity. In addition, Pb isotope source analysis indicated that the Pb in the awn and grain mainly originated from atmospheric deposition, and the de-awned treatment decreased the proportion of grain Pb from atmospheric deposition by 8.9 %. Microstructural observations further confirmed that the contribution of awns to grain Pb accumulation mainly originated from their direct absorption of atmospheric Pb. In conclusion, awns play an important role in wheat grain Pb absorption at the late grain-filling stage; planting awnless or short-awn wheat varieties may be the simplest and effective environmental management measure to reduce the health risks of Pb in wheat in regions with serious atmospheric Pb contamination.


Assuntos
Chumbo , Triticum , Triticum/química , Chumbo/análise , Grão Comestível/química , Poluição Ambiental , Fotossíntese
2.
Phys Chem Chem Phys ; 24(8): 5199-5210, 2022 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-35166747

RESUMO

The p53 protein is a tumor suppressor crucial for cell cycle and genome integrity. In a very large proportion of human cancers, p53 is frequently inactivated by mutations located in its DNA-binding domain (DBD). Some experimental studies reported that the inherited R337H mutation located in the p53 tetramerization domain (p53TD) can also result in destabilization of the p53 protein, and consequently lead to an organism prone to cancer setup. However, the underlying R337H mutation-induced structural destabilization mechanism is not well understood. Herein, we investigate the structural stability and dynamic property of the wild type p53TD tetramer and its cancer-related R337H mutant by performing multiple microsecond molecular dynamics simulations. It is found that R337H mutation destroys the R337-D352 hydrogen bonds, weakens the F341-F341 π-π stacking interaction and the hydrophobic interaction between aliphatic hydrocarbons of R337 and M340, leading to more solvent exposure of all the hydrophobic cores, and thus disrupting the structural integrity of the tetramer. Importantly, our simulations show for the first time that R337H mutation results in unfolding of the α-helix starting from the N-terminal region (residues 335RER(H)FEM340). Consistently, community network analyses reveal that R337H mutation reduces dynamical correlation and global connectivity of p53TD tetramer, which destabilizes the structure of the p53TD tetramer. This study provides the atomistic mechanism of R337H mutation-induced destabilization of p53TD tetramer, which might be helpful for in-depth understanding of the p53 loss-of-function mechanism.


Assuntos
Neoplasias , Proteína Supressora de Tumor p53/química , Humanos , Ligação de Hidrogênio , Simulação de Dinâmica Molecular , Mutação , Neoplasias/genética
3.
Cytopathology ; 33(4): 499-504, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35038367

RESUMO

OBJECTIVE: To analyse the cytopathological features of fine needle aspiration (FNA) in angioimmunoblastic T-cell lymphoma (AITL) diagnostics. METHODS: Fine needle aspiration lymph node biopsy samples from 12 patients with AITL were collected at a single centre between January 2014 and December 2020. The clinical, cytological and histopathological characteristics were retrospectively analysed. RESULTS: Three male and six female patients with AITL who had a median onset age of 65 years (range 51-74 years) and a mean follow-up period of 29 months (range 12-47 months) were included. The FNA cytological and morphological analysis of the reactive lymph node background revealed diffusely distributed non-homogeneous mixed lymphocytes, including mature small lymphocytes, medium-sized lymphoid cells, immune cells, and plasma cells; some mixed eosinophils, macrophages, and an occasional mixture of visible and medium-sized lymphocytes and epithelioid cells were observed. Mitotically active lymphocytes and sporadic pigmented bodies were observed occasionally. An abnormal proliferation of follicular dendritic cells observed under the microscope is important for AITL diagnosis, and these cells are often distributed in a scattered pattern of small clusters with many nuclear morphologies. Branched capillaries are another important diagnostic clue. Two patients with AITL who achieved clinical remission after treatment experienced recurrence and were diagnosed using FNA and cell block immunohistochemistry. CONCLUSIONS: Fine needle aspiration provides clues for the diagnosis of AITL in special clinical situations, and cell block immunohistochemistry is worthy of further exploration.


Assuntos
Linfadenopatia Imunoblástica , Linfoma de Células T , Biópsia por Agulha Fina , Criança , Pré-Escolar , Feminino , Humanos , Linfadenopatia Imunoblástica/diagnóstico , Linfadenopatia Imunoblástica/patologia , Imuno-Histoquímica , Linfoma de Células T/diagnóstico , Linfoma de Células T/patologia , Masculino , Estudos Retrospectivos
4.
Nanotechnology ; 32(50)2021 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-34479223

RESUMO

The rational design of cathode materials with core-shell heterostructures is significant to develop a Ni//Zn battery with both high gravimetric and areal energy density under high mass loading. In this work, the NiCo-OH nanothorns with a mass loading of 11.6 mg cm-2were coated on CuO nanowire arrays via a chemical bath deposition method. Thanks to the construction of 3D core-shell nanowire arrays and appropriate cobalt doping, as-fabricated Ni//Zn battery based on the NiCo-OH as cathode achieved the maximum specific capacity of 383 mAh g-1at 5 mA cm-2with high energy density of 649 Wh kg-1at 0.73 kW kg-1, indicating good energy storage performance in Ni//Zn battery.

5.
Nanotechnology ; 31(36): 365405, 2020 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-32438364

RESUMO

Cosmetic brush-like Co3O4 nanowires grown on carbon cloth were prepared by regulating the addition of trisodium citrate by hydrothermal synthesis. Then a simple liquid-phase ion exchange was carried out to improve the electrochemical performance of Co3O4 by surface modification with Ni2+. After surface modification, at a current density of 4 A g-1, the specific capacity significantly increased from 276.1 C g-1 (720.5 F g-1) to 655.9 C g-1 (1525.4 F g-1). Meanwhile, the electrocatalytic oxidation performances of methanol and urea were also improved significantly. The enhanced electrochemical properties were attributed to the modification of the surface of Co3O4 with Ni2+.

6.
Nanotechnology ; 31(16): 165709, 2020 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-31899902

RESUMO

High-efficiency and low-cost electrocatalysts are generally believed to be the critical factor and have been highly researched to catalyze the oxygen reduction reaction (ORR) during the operation of Li-O2 battery (LOB). The catalysts with better ORR performance are essential for high-performance LOBs. Herein, a binder-free MnO x @carbon cloth cathode composed of Mn3O4 nanoparticles and Mn2O3 nanosheets were directly synthesized on the carbon cloth by electrodeposition and subsequently heat treatment at different temperature (from 200 °C to 400 °C). With the increase of temperature, the Mn3O4 nanospheres gradually transformed into Mn2O3 nanosheets. The MnO x obtained at 350 °C exhibited the best ORR performance. And MnO x -350 °C could operate more than 80 cycles at 340 mA g-1 with a limiting specific capacity of 1000 mAh g-1, and its first discharge specific capacity could nearly achieve 8000 mAh g-1 at 200 mA g-1.

7.
Int J Mol Sci ; 20(3)2019 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-30754626

RESUMO

The gene Pm61 that confers powdery mildew resistance has been previously identified on chromosome arm 4AL in Chinese wheat landrace Xuxusanyuehuang (XXSYH). To facilitate the use of Pm61 in breeding practices, the bulked segregant analysis-RNA-Seq (BSR-Seq) analysis, in combination with the information on the Chinese Spring reference genome sequence, was performed in the F2:3 mapping population of XXSYH × Zhongzuo 9504. Two single nucleotide polymorphism (SNP), two Kompetitive Allele Specific PCR (KASP), and six simple sequence repeat (SSR) markers, together with previously identified polymorphic markers, saturated the genetic linkage map for Pm61, especially in the proximal side of the target gene that was short of gene-linked markers. In the newly established genetic linkage map, Pm61 was located in a 0.71 cM genetic interval and can be detected in a high throughput scale by the KASP markers Xicsk8 and Xicsk13 or by the standard PCR-based markers Xicscx497 and Xicsx538. The newly saturated genetic linkage map will be useful in molecular marker assisted-selection of Pm61 in breeding for disease resistant cultivar and in its map-based cloning.


Assuntos
Mapeamento Cromossômico , Ligação Genética , Sequenciamento de Nucleotídeos em Larga Escala , Repetições de Microssatélites , Doenças das Plantas/genética , Polimorfismo de Nucleotídeo Único , Resistência à Doença/genética , Perfilação da Expressão Gênica , Genes de Plantas , Marcadores Genéticos , Interações Hospedeiro-Patógeno/genética , Doenças das Plantas/microbiologia , Análise de Sequência de DNA , Triticum/genética , Triticum/microbiologia
8.
Genome Res ; 23(3): 530-8, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23222846

RESUMO

Zinc-finger nucleases (ZFNs) are important tools for genome engineering. Despite intense interest by many academic groups, the lack of robust noncommercial methods has hindered their widespread use. The modular assembly (MA) of ZFNs from publicly available one-finger archives provides a rapid method to create proteins that can recognize a very broad spectrum of DNA sequences. However, three- and four-finger arrays often fail to produce active nucleases. Efforts to improve the specificity of the one-finger archives have not increased the success rate above 25%, suggesting that the MA method might be inherently inefficient due to its insensitivity to context-dependent effects. Here we present the first systematic study on the effect of array length on ZFN activity. ZFNs composed of six-finger MA arrays produced mutations at 15 of 21 (71%) targeted loci in human and mouse cells. A novel drop-out linker scheme was used to rapidly assess three- to six-finger combinations, demonstrating that shorter arrays could improve activity in some cases. Analysis of 268 array variants revealed that half of MA ZFNs of any array composition that exceed an ab initio B-score cutoff of 15 were active. These results suggest that, when used appropriately, MA ZFNs are able to target more DNA sequences with higher success rates than other current methods.


Assuntos
DNA/isolamento & purificação , Endonucleases/genética , Engenharia de Proteínas , Dedos de Zinco/genética , Animais , DNA/genética , Análise Mutacional de DNA , Ensaio de Desvio de Mobilidade Eletroforética , Endonucleases/metabolismo , Loci Gênicos , Células HEK293 , Humanos , Camundongos , Análise de Sequência de DNA
9.
J Biol Chem ; 287(31): 25808-20, 2012 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-22689570

RESUMO

ClC-1 is the dominant sarcolemmal chloride channel and plays an important role in regulating membrane excitability that is underscored by ClC-1 mutations in congenital myotonia. Here we show that the coenzyme ß-nicotinamide adenine dinucleotide (NAD), an important metabolic regulator, robustly inhibits ClC-1 when included in the pipette solution in whole cell patch clamp experiments and when transiently applied to inside-out patches. The oxidized (NAD(+)) form of the coenzyme was more efficacious than the reduced (NADH) form, and inhibition by both was greatly enhanced by acidification. Molecular modeling, based on the structural coordinates of the homologous ClC-5 and CmClC proteins and in silico docking, suggest that NAD(+) binds with the adenine base deep in a cleft formed by ClC-1 intracellular cystathionine ß-synthase domains, and the nicotinamide base interacts with the membrane-embedded channel domain. Consistent with predictions from the models, mutation of residues in cystathionine ß-synthase and channel domains either attenuated (G200R, T636A, H847A) or abrogated (L848A) the effect of NAD(+). In addition, the myotonic mutations G200R and Y261C abolished potentiation of NAD(+) inhibition at low pH. Our results identify a new biological role for NAD and suggest that the main physiological relevance may be the exquisite sensitivity to intracellular pH that NAD(+) inhibition imparts to ClC-1 gating. These findings are consistent with the reduction of sarcolemmal chloride conductance that occurs upon acidification of skeletal muscle and suggest a previously unexplored mechanism in the pathophysiology of myotonia.


Assuntos
Canais de Cloreto/metabolismo , Músculo Esquelético/metabolismo , NAD/fisiologia , Trifosfato de Adenosina/farmacologia , Trifosfato de Adenosina/fisiologia , Sequência de Aminoácidos , Substituição de Aminoácidos , Animais , Sítios de Ligação , Linhagem Celular , Canais de Cloreto/antagonistas & inibidores , Canais de Cloreto/genética , Simulação por Computador , Humanos , Concentração de Íons de Hidrogênio , Líquido Intracelular , Cinética , Potenciais da Membrana , Modelos Moleculares , Dados de Sequência Molecular , Músculo Esquelético/citologia , Mutagênese Sítio-Dirigida , NAD/farmacologia , Oócitos/metabolismo , Oócitos/fisiologia , Técnicas de Patch-Clamp , Ligação Proteica , Estrutura Terciária de Proteína , Xenopus
10.
J Hazard Mater ; 443(Pt B): 130284, 2023 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-36332279

RESUMO

Rapeseed cultivation is a novel approach to safely utilizing lead (Pb) contaminated farmland. However, the mechanism of Pb absorption in seeds remains uncertain. A field experiment was conducted to explore this mechanism with two contrasting treatments: rapeseed exposed to atmospheric deposition and non-exposed treatment. Non-exposed treatment ultimately decreased Pb content in leaf, silique, and seed by 46.7%, 53.7%, and 53.6%, respectively. Sub-microstructure analysis further confirmed that rapeseed leaves and siliques could directly absorb atmospheric Pb. In addition, Pb isotope analysis indicates that atmospheric deposition is the primary source of silique and seed Pb. The root and silique organs had relative Pb contributions of 28.0% and 72.0%, respectively, to seed. Thus, the direct absorption of atmospheric Pb by siliques during the filling stage was found to be the leading cause of seed Pb pollution.


Assuntos
Brassica napus , Brassica rapa , Chumbo/análise , Sementes/química , Poluição Ambiental
11.
J Phys Chem B ; 127(36): 7708-7720, 2023 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-37665658

RESUMO

Aggregation of p53 mutants can result in loss-of-function, gain-of-function, and dominant-negative effects that contribute to tumor growth. Revealing the mechanisms underlying mutation-enhanced p53 aggregation and dissecting how small molecule inhibitors prevent the conversion of p53 into aggregation-primed conformations are fundamentally important for the development of novel therapeutics for p53 aggregation-associated cancers. A recent experimental study shows that resveratrol (RSV) has an inhibitory effect on the aggregation of hot-spot R248Q mutant of the p53 core domain (p53C), while pterostilbene (PT) exhibits a relatively poor inhibitory efficacy. However, the conformational properties of the R248Q mutant leading to its enhanced aggregation propensity and the inhibitory mechanism of RSV against p53C aggregation are not well understood. Herein, we performed extensive all-atom molecular dynamics simulations on R248Q p53C in the absence and presence of RSV/PT, as well as wild-type (WT) p53C. Our simulations reveal that loop L3, where the mutation resides, remains compact in WT p53C, while it becomes extended in the R248Q mutant. The extension of loop L3 weakens the interactions between loop L3 and two crucial aggregation-prone regions (APRs) of p53C, leading to impaired interactions within the APRs and their structural destabilization as well as p53C. The destabilized APRs in the R248Q mutant are more exposed than in WT p53C, which is conducive to p53C aggregation. RSV has a higher preference to bind to R248Q p53C than PT. This binding not only stabilizes loop L3 of R248Q mutant to its WT-like conformation, preventing L3-extension-caused APRs' destabilization but also reduces APRs' solvent exposure, thereby inhibiting R248Q p53C aggregation. However, PT exhibits a lower hydrogen-bonding capability and a higher self-association propensity, which would lead to a reduced p53C binding and a weakened inhibitory effect on R248Q mutant aggregation. Our study provides mechanistic insights into the R248Q mutation-enhanced aggregation propensity and RSV's potent inhibition against R248Q p53C aggregation.


Assuntos
Proteína Supressora de Tumor p53 , Resveratrol/farmacologia , Proteína Supressora de Tumor p53/genética , Mutação
12.
Int J Gen Med ; 16: 1081-1089, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36999008

RESUMO

Purpose: To investigate the value of immunocytochemical (ICC) staining for human papillomavirus (HPV) E7 protein (E7-ICC staining) as a new-generation immunological method in the cytological diagnosis of cervical lesions. Methods: The exfoliated cervical cell samples of 690 women were subjected to a liquid-based cytology test (LCT), high-risk HPV (HR-HPV) test, E7-ICC staining, and cervical biopsy for pathological diagnosis. Results: E7-ICC staining as a preliminary screening scheme for cervical precancerous lesions was comparable to the HR-HPV test in sensitivity and to the LCT in specificity. E7-ICC staining was advantageous in facilitating the secondary triage of HR-HPV-positive patients; therefore, this method can be used as an auxiliary scheme to routine LCT for diagnostic grading to improve the accuracy of cervical cytology. Conclusion: E7-ICC staining as a primary or auxiliary cytological screening scheme can effectively reduce the colposcopy referral rate.

13.
J Environ Public Health ; 2022: 7364473, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36213030

RESUMO

With the progress of science and technology and the arrival of the big data era, people increasingly rely on computers to deal with daily life and related affairs. In recent years, machine learning has become more and more popular and has achieved good results in some fields, which also makes machine learning widely used. Among them, visual neural network technology can more intelligently analyze the emotional expression of oil painting, which is one of the current research hotspots, involving machine vision, pattern recognition, image processing, artificial intelligence, and other fields. However, in the art field, oil painting is still very different from other images. At present, there is no deep learning algorithm to identify the application of emotional expression analysis in oil painting theme creation. This paper will start with the neural network algorithm and combine the big data recognition technology to analyze the emotional expression of the oil painting subject in the public environment and establish the emotional expression analysis model of oil painting creation based on big data and neural network. The experiment shows that the graphics synthesized by this model have high resolution and good definition, but the speed is slow in the process of experimental operation. It takes about one hour to complete a round of image optimization.


Assuntos
Inteligência Artificial , Big Data , Algoritmos , Humanos , Redes Neurais de Computação , Tecnologia
14.
Am J Case Rep ; 23: e934617, 2022 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-35091526

RESUMO

BACKGROUND Incarcerated inguinal hernias (IGHs) combined with abdominal cocoons (ACs) are uncommon in adults. Abdominal cavity exploration using laparoscopy via the hernial sac (hernioscopy) has rarely been reported. Here, an elderly man with unilateral IGH complicated by a contralateral inguinal hernia and AC was found using hernioscopy. We present the surgical decision-making points in an elderly patient with IGH, enrich the diversity of AC, and propose a relatively novel hernioscopy approach. CASE REPORT A 90-year-old man presented with chronic constipation and reducible right inguinal masses. A lump in the right groin was strangulated for 2 days, accompanied with progressive abdominal pain, distension, and vomiting. The levels of inflammatory markers were elevated. Abdominal computed tomography revealed a dilated small bowel and a large mass in the right groin. Subsequently, the patient's condition quickly deteriorated. Therefore, he underwent surgical repair of bilateral hernias. Additionally, in our hospital, a total of 46 patients underwent hernioscopy because of IGH. No intraoperative or postoperative complications were observed. According to our clinical practice, hernioscopy via the bilateral hernial sacs was performed in this elderly patient. We found that almost the entire small bowel and colon were encapsulated in a fibrous and cocoon-like membrane, which postoperative pathological results revealed as AC. CONCLUSIONS This is the first report to reveal that AC complicated with IGH could occur in a 90-year-old man. Hernioscopy is a relatively novel and safe surgical approach to abdominal pathology associated with incarcerated or strangulated inguinal hernias. It is rarely used in adults with IGH.


Assuntos
Hérnia Inguinal , Laparoscopia , Abdome , Adulto , Idoso , Idoso de 80 Anos ou mais , Colo , Hérnia Inguinal/diagnóstico por imagem , Hérnia Inguinal/cirurgia , Humanos , Intestino Delgado , Masculino
15.
Front Bioeng Biotechnol ; 10: 883545, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35903797

RESUMO

Traumatic brain injury (TBI), which is mainly caused by impact, often results in chronic neurological abnormalities. Since the pathological changes in vivo during primary biomechanical injury are quite complicated, the in-depth understanding of the pathophysiology and mechanism of TBI depends on the establishment of an effective experimental in vitro model. Usually, a bomb explosive blast was employed to establish the in vitro model, while the process is complex and unsuitable in the lab. Based on water-hammer, we have developed a device system to provide a single dynamic compression stress on living cells. A series of amplitude (∼5.3, ∼9.8, ∼13.5 MPa) were generated to explore the effects of dynamic compression loading on primary microglia within 48 h. Apoptosis experiments indicated that primary microglia had strong tolerance to blast waves. In addition, the generation of intercellular reactive oxygen species and secretory nitric oxide was getting strongly enhanced and recovered within 48 h. In addition, there is a notable release of pro-inflammatory cytokine by microglia. Our work provides a reproducible and peaceable method of loading single dynamic compression forces to cells in vitro. Microglia showed an acute inflammatory response to dynamic loadings, while no significant cell death was observed. This insight delivers a new technological approach that could open new areas to a better understanding of the mechanism of cell blast injuries.

16.
Ann Palliat Med ; 10(5): 5706-5713, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-34107714

RESUMO

BACKGROUND: At present, the treatment of acute ischaemic stroke (AIS) by aticepase (rt-PA) in emergency veins has become the main treatment mode in hospital, but the research on early hemorrhage complications in patients with emergency thrombolysis is rarely reported. This research aims to study the earlier warning index of early hemorrhage complications in patients with emergency thrombolysis. METHODS: A retrospective analysis was performed on the clinical data of rt-PA intravenous thrombolysis-treated AIS patients in the advanced stroke center of the emergency department of a tertiary grade hospital from January 2018 to May 2020. Patients were divided into a hemorrhage group and non-hemorrhage group according to the hemorrhage situation within 24 hours after thrombolytic therapy. The differences between the 2 groups in terms of pre-thrombolysis risk factors were analyzed. Logistic regression analysis was used to analyze the independent risk factors associated with post-thrombolysis hemorrhage. RESULTS: After intravenous thrombolysis, the hemorrhage group had 91 cases and the non-hemorrhage group had 146 cases. Logistic regression analysis showed that atrial fibrillation, systolic blood pressure before thrombolysis, platelet count, and antiplatelet drugs were independent risk factors for hemorrhage after intravenous thrombolysis (P<0.05). CONCLUSIONS: Patients with AIS have a higher incidence of hemorrhage after intravenous thrombolysis. Atrial fibrillation, systolic blood pressure before thrombolysis, platelet count, and antiplatelet drugs were independent risk factors for hemorrhage after intravenous thrombolysis. These independent risk factors can provide a basis for clinical nurses to evaluate hemorrhage risk in AIS patients after intravenous thrombolysis.


Assuntos
Isquemia Encefálica , AVC Isquêmico , Acidente Vascular Cerebral , Isquemia Encefálica/tratamento farmacológico , Serviço Hospitalar de Emergência , Fibrinolíticos/efeitos adversos , Hemorragia , Humanos , Estudos Retrospectivos , Fatores de Risco , Acidente Vascular Cerebral/tratamento farmacológico , Terapia Trombolítica/efeitos adversos , Resultado do Tratamento
17.
PLoS One ; 15(12): e0240704, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33362212

RESUMO

CLC-0, a prototype Cl- channel in the CLC family, employs two gating mechanisms that control its ion-permeation pore: fast gating and slow gating. The negatively-charged sidechain of a pore glutamate residue, E166, is known to be the fast gate, and the swinging of this sidechain opens or closes the pore of CLC-0 on the millisecond time scale. The other gating mechanism, slow gating, operates with much slower kinetics in the range of seconds to tens or even hundreds of seconds, and it is thought to involve still-unknown conformational rearrangements. Here, we find that low intracellular pH (pHi) facilitates the closure of the CLC-0's slow gate, thus generating current inhibition. The rate of low pHi-induced current inhibition increases with intracellular H+ concentration ([H+]i)-the time constants of current inhibition by low pHi = 4.5, 5.5 and 6 are roughly 0.1, 1 and 10 sec, respectively, at room temperature. In comparison, the time constant of the slow gate closure at pHi = 7.4 at room temperature is hundreds of seconds. The inhibition by low pHi is significantly less prominent in mutants favoring the slow-gate open state (such as C212S and Y512A), further supporting the fact that intracellular H+ enhances the slow-gate closure in CLC-0. A fast inhibition by low pHi causes an apparent inverted voltage-dependent activation in the wild-type CLC-0, a behavior similar to those in some channel mutants such as V490W in which only membrane hyperpolarization can open the channel. Interestingly, when V490W mutation is constructed in the background of C212S or Y512A mutation, the inverted voltage-dependent activation disappears. We propose that the slow kinetics of CLC-0's slow-gate closure may be due to low [H+]i rather than due to the proposed large conformational change of the channel protein. Our results also suggest that the inverted voltage-dependent opening observed in some mutant channels may result from fast closure of the slow gate by the mutations.


Assuntos
Canais de Cloreto/metabolismo , Cloretos/metabolismo , Ativação do Canal Iônico , Prótons , Canais de Cloreto/genética , Ácido Glutâmico/genética , Células HEK293 , Humanos , Concentração de Íons de Hidrogênio , Cinética , Potenciais da Membrana , Mutagênese Sítio-Dirigida , Mutação , Técnicas de Patch-Clamp , Homologia Estrutural de Proteína
19.
Onco Targets Ther ; 12: 4281-4285, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31213845

RESUMO

The incidence of synchronous multiple primary lung cancer (SMPLC) has been increased in recent years. Because of a variance in clinical management and outcome, it is important to distinguish SMPLC from a primary tumor with intrapulmonary metastases. Here, we reported a diagnosis and treatment procedure regarding a case of a 58-year-old woman who presented with synchronous multiple tumor lesions in separate lungs. Using a next generation sequencing technology, a discordant EGFR gene profile from the separate lungs was revealed for this patient. After standard treatment procedures, the therapeutic effects were evaluated by response evaluation criteria in solid tumors (RECIST). This case shows an essential role in the combination of molecular features, together with pathological analysis, during the management of SMPLC, but challenges still required considering during dealing the cases of SMPLC.

20.
Huan Jing Ke Xue ; 40(2): 987-993, 2019 Feb 08.
Artigo em Chinês | MEDLINE | ID: mdl-30628368

RESUMO

The effects of biochar addition to compost on change characteristics and passivation effect of heavy metals (Cd, Pb, Cu, Zn, Ni) were investigated during the process of sludge composting with two different composts (group A:with biochar; group B:without biochar) and land application of compost. The results indicated that the total amount of heavy metals (except Ni) did not change significantly during the process of sludge composting and land application of compost. Additionally, biochar addition had little effect on the total amount of heavy metals. During the sludge composting process, five heavy metals (Cd, Pb, Cu, Zn, Ni) were passivated. Sludge composting with the addition of biochar can decrease the available contents of heavy metals, and the passivation effect of heavy metals was significant (P<0.05). The passivation rate of the five examined heavy metals (Cd, Pb, Cu, Zn, Ni)ranged from 16.39%-43.10%, and the passivation effect for Zn and Ni was more significant. However, the passivation effect was not significant in the sludge composting process without the addition of biochar (P>0.05). The concentrations of heavy metals in soil increased with the application of sewage sludge compost products. In the short term, biochar had a certain passivation effect on the available heavy metals in soils with sludge compost application, but the effect was not significant.


Assuntos
Carvão Vegetal , Compostagem , Metais Pesados/análise , Esgotos , Solo/química
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