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1.
J Am Heart Assoc ; 10(7): e016201, 2021 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-33719504

RESUMO

Background There was little evidence about the role of objective sleep efficiency (SE) in the incidence of major cardiovascular disease (CVD) events. The purpose of this study was to investigate the correlation between objective SE and CVD based on polysomnography. Methods and Results A total of 3810 participants from the SHHS (Sleep Heart Health Study) were selected in the current study. CVD was assessed during an almost 11-year follow-up period. The primary composite cardiovascular outcome was major adverse cardiovascular events, defined as CVD mortality, congestive heart failure, myocardial infarction, and stroke. The secondary composite cardiovascular outcome was major adverse cardiovascular event plus revascularization. Objective measured SE, including SE and wake after sleep onset, was based on in-home polysomnography records. Cox regression analysis was used to explore the association between SE and CVD. After multivariate Cox regression analysis, poor SE (<80%) was significantly associated with primary (hazard ratio [HR], 1.338; 95% CI, 1.025-1.745; P=0.032) and secondary composite cardiovascular outcomes (HR, 1.250; 95% CI, 1.027-1.521; P=0.026); it was also found to be a predictor of CVD mortality (HR, 1.887; 95% CI, 1.224-2.909; P=0.004). Moreover, wake after sleep onset of fourth quartile (>78.0 minutes) was closely correlated with primary (HR, 1.436; 95% CI, 1.066-1.934; P=0.017), secondary composite cardiovascular outcomes (HR, 1.374; 95% CI, 1.103-1.712; P=0.005), and CVD mortality (HR, 2.240; 95% CI, 1.377-3.642; P=0.001). Conclusions Poor SE and long wake after sleep onset, objectively measured by polysomnography, were associated with the increased risk of incident CVD.

2.
Pharmacol Biochem Behav ; 204: 173156, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33675839

RESUMO

The relationship between circadian rhythms and mood disorders has been established. Circadian dysregulations are believed to exacerbate the severity of mood disorders and vice versa. Although many studies on diurnal changes of clock genes in animal model of depression have been performed from the RNA level, only a few studies have been carried out from the protein level. In this study, we investigated the diurnal changes induced by chronic unpredictable stress (CUS) using free-running wheel test and Western Blotting (WB). Besides, we examined the depression-like behaviors of rats by sucrose preference test (SPT) and forced swim test (FST). We found that CUS induced significant reductions in the quantity of free-running wheel activity and rhythmic disruptions of clock proteins in hippocampus. Furthermore, we found that the amplitude of PER1 in CA1 was positively related to the severity of depression-like behaviors. These results suggest that CUS results in both changes in diurnal rhythms and in depression-like behaviors and that it is suggested that these changes are related.

3.
J Clin Sleep Med ; 2021 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-33779541

RESUMO

STUDY OBJECTIVES: Sleep fragmentation (SF) has been reported to be associated with cardiovascular risk. The aim of this study was to explore the relationship between SF and congestive heart failure (CHF). METHODS: A total of 4,887 participants (2,256 males and 2,631 females, mean age of 63.6 ± 11.0 years) from the Sleep Heart Health Study (SHHS) were included in this study. Incident CHF was defined as the first occurrence of CHF between baseline in-home polysomnography (PSG) and the end of follow-up. Objective assessments for SF, including sleep fragmentation index (SFI), arousal index (ArI), sleep efficiency (SE), and wake after sleep onset (WASO), were determined based on in-home polysomnography records. Multivariate Cox regression analysis was used to investigate the relationship between SF and incident CHF. RESULTS: During an average of 10 years of follow-up, 543 participants with CHF (11.1%) were observed. Individuals with CHF had a significantly higher SFI, total ArI, and WASO and a lower SE than controls. After multivariate Cox regression analysis, SE (odds ratio [OR], 0.967; 95% confidence interval [CI] 0.955-0.978; P < 0.001), WASO (OR, 1.009; 95% CI 1.006-1.012; P < 0.001), SFI (OR, 1.046; CI 1.007-1.086; P = 0.021), and total ArI (OR, 1.018; 95% CI 1.000-1.035; P = 0.044) were found to be associated with the incidence of CHF in participants without hypertension. CONCLUSIONS: Objectively measured SF was associated with the incidence of CHF. The role of SFI, total ArI, SE, and WASO deserves further investigation.

4.
Opt Express ; 29(3): 4048-4057, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33770992

RESUMO

We demonstrate a watt-level mid-infrared supercontinuum source, with the spectrum covering the infrared region from 2 to 6.5 µm, in an all-fiber structured laser transmission system. To further improve the SC spectral bandwidth, power and system compactness in the follow-up As2S3 fiber, we theoretically and experimentally explored some knotty problems that would potentially result in the As2S3 fiber end-facet failure and low SC output power during the high-power butt-coupling process and proposed an optimal coupling distance on the premise of the safety of As2S3 fiber end face. In addition, we also built a multi-pulse pumping model for the first time to more precisely estimate the SC spectral evolution in As2S3 fiber. This work will give an important reference to someone who is working on the all-fiber structured, high-power mid- and far-infrared supercontinuum source.

5.
Clin Interv Aging ; 16: 311-323, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33654388

RESUMO

Background: Studies concerning the impact of the AT(N) framework on diagnostic capability in the dementia population are lacking. We aimed to explore the diagnostic application of CSF AT(N) framework in clinical routines of Alzheimer's disease (AD) as well as differential diagnosis of other cognitive diseases in the Chinese Han population. Patients and Methods: A total of 137 patients with cognitive disorders received CSF tests of Aß42, t-tau and p-tau181. Their CSF biomarker results were categorized and interpreted by the AT(N) framework. Neurologists provided a diagnosis both pre- and post-CSF biomarker disclosure with corresponding diagnostic confidence. Results: The total initial diagnosis included 79 patients with AD and 58 patients with non-AD (NAD). The results of CSF biomarkers led to a diagnostic change of 28% in the cohort. Approximately 81.5% (n=53) of 65 patients whose CSF biomarker showed an underlying AD pathology were finally diagnosed as AD, with an increase of 17.5% in diagnostic confidence. Thirty-seven CSF results indicating NAD pathologic changes contributed to an exclusion of AD in 56.8% (n=21) of the patients along with a modest increase of 9.8% in average confidence. Thirty-five patients with normal CSF biomarkers maintained the diagnosis of NAD in 68.6% (n=24) of the group, leading to a slight elevation of 7.6% in confidence. Conclusion: We found that the presence of amyloid pathology (A+) is contributable to diagnosing AD and improving confidence. On occasion of negative amyloid pathology (A-), with or without tau pathology, gaining uncertainty of the primary AD diagnosis would diminish the corresponding confidence. To the best of our knowledge, this is the first study performed in the Chinese Han population with cognitive disorders that explores the clinical capability of CSF AT(N) framework in a quantitative way.

6.
Appl Opt ; 60(7): 1843-1850, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33690272

RESUMO

Cone-beam computed tomography is a noninvasive detection system that can obtain the three-dimensional structure of objects in a way that does not damage the object. It is widely applied in precision instruments, medical detection, and other fields. However, in the actual process, if a geometric artifact appears in the results, it will affect the quality of reconstructed images, including detail loss and decreased spatial resolution, which leads to inaccurate distinction of defects in detection. We propose a method for correcting a geometric artifact by means of data-driven projection and neural networks. The network designed is a deep neural network with six convolutional layers and six deconvolutional layers that can correct a geometric artifact by training a large number of labeled data and unlabeled data. Compared with other networks that require prior information for reconstructed images, the proposed method uses a projection data-driven approach that can avoid the requirement for prior information. The simulation data have been tested under varying degrees of noise, and satisfactory geometric artifact correction results have been obtained. Meanwhile, we use the actual data of line pairs and ball grid array solder joints to conduct experiments. The results obtained by our method are compared with two other phantom-based method and the U-net method, respectively. The results of similarity and spatial resolution show that the proposed method can achieve the comparable results as the two types of methods. At the same time, we apply a projection data-driven approach to avoid the requirement for prior information, which is more conducive to the correction of the geometric artifact in practical situations where prior information is lacking.

7.
J Am Heart Assoc ; 10(6): e018385, 2021 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-33666090

RESUMO

Background Previous studies have suggested that sleep timing is associated with cardiovascular risk factors. However, there is no evidence on the relationship between sleep timing and congestive heart failure (CHF). We aimed to examine this relationship in this study. Methods and Results We recruited 4765 participants (2207 men; mean age, 63.6±11.0 years) from the SHHS (Sleep Heart Health Study) database in this multicenter prospective cohort study. Follow-up was conducted until the first CHF diagnosis between baseline and the final censoring date. Sleep timing (bedtimes and wake-up times on weekdays and weekends) was based on a self-reported questionnaire. Cox proportional hazard models were constructed to investigate the association between sleep timing and CHF. During the mean follow-up period of 11 years, 519 cases of CHF (10.9%) were reported. The multivariable Cox proportional hazards models revealed that participants with weekday bedtimes >12:00 am (hazard ratio [HR], 1.56; 95% CI, 1.15-2.11; P=0.004) and from 11:01 pm to 12:00 am (HR, 1.25; 95% CI, 1.00-1.56; P=0.047) had an increased risk of CHF compared with those with bedtimes from 10:01 pm to 11:00 pm. After stratified analysis, the association was intensified in participants with a self-reported sleep duration of 6 to 8 hours. Furthermore, wake-up times >8:00 am on weekdays (HR, 1.53; 95% CI, 1.07-2.17; P=0.018) were associated with a higher risk of incident CHF than wake-up times ≤6:00 am. Conclusions Delayed bedtimes (>11:00 pm) and wake-up times (>8:00 am) on weekdays were associated with an increased risk of CHF.

8.
Phys Rev Lett ; 126(7): 070602, 2021 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-33666449

RESUMO

We explore nonadiabatic quantum phase transitions in an Ising spin chain with a linearly time-dependent transverse field and two different spins per unit cell. Such a spin system passes through critical points with gapless excitations, which support nonadiabatic transitions. Nevertheless, we find that the excitations on one of the chain sublattices are suppressed in the nearly adiabatic regime exponentially. Thus, we reveal a coherent mechanism to induce exponentially large density separation for different quasiparticles.

9.
Cancers (Basel) ; 13(4)2021 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-33669381

RESUMO

Pancreatic ductal adenocarcinoma (PDAC) is extremely malignant and the therapeutic options available usually have little impact on survival. Great hope is placed on new therapeutic targets, including long noncoding RNAs (lncRNAs), and on the development of new drugs, based on e.g., broccoli-derived sulforaphane, which meanwhile has shown promise in pilot studies in patients. We examined whether sulforaphane interferes with lncRNA signaling and analyzed five PDAC and two nonmalignant cell lines, patient tissues (n = 30), and online patient data (n = 350). RT-qPCR, Western blotting, MTT, colony formation, transwell and wound healing assays; gene array analysis; bioinformatics; in situ hybridization; immunohistochemistry and xenotransplantation were used. Sulforaphane regulated the expression of all of five examined lncRNAs, but basal expression, biological function and inhibition of H19 were of highest significance. H19 siRNA prevented colony formation, migration, invasion and Smad2 phosphorylation. We identified 103 common sulforaphane- and H19-related target genes and focused to the virus-induced tumor promoter APOBEC3G. APOBEC3G siRNA mimicked the previously observed H19 and sulforaphane effects. In vivo, sulforaphane- or H19 or APOBEC3G siRNAs led to significantly smaller tumor xenografts with reduced expression of Ki67, APOBEC3G and phospho-Smad2. Together, we identified APOBEC3G as H19 target, and both are inhibited by sulforaphane in prevention of PDAC progression.

10.
Insects ; 12(3)2021 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-33673724

RESUMO

Host plant preference during the larval stage may help shape not only phenotypic plasticity but also behavioral isolation. We assessed the effects of diet on population parameters and mate choice in Spodoptera litura. We raised larvae fed on tobacco, Chinese cabbage, or an artificial diet, and we observed the shortest developmental time and highest fecundity in individuals fed the artificial diet. However, survival rates were higher for larvae on either of the natural diets. Population parameters including intrinsic rate of increase and finite rate of increase were significantly higher with the artificial diet, but this diet led to a lower mean generation time. Copulation duration, copulation time, and number of eggs reared significantly differed between diets. In terms of mate choice, females on the artificial diet rarely mated with males fed on a natural host. Our results support the hypothesis that different diets may promote behavioral isolation, affecting mating outcomes. Thus, findings for populations fed an artificial diet may not reflect findings for populations in the field.

11.
Front Cell Infect Microbiol ; 11: 640309, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33777850

RESUMO

To characterize the salivary microbiota in patients at different progressive histological stages of gastric carcinogenesis and identify microbial markers for detecting gastric cancer, two hundred and ninety-three patients were grouped into superficial gastritis (SG; n = 101), atrophic gastritis (AG; n = 93), and gastric cancer (GC; n = 99) according to their histology. 16S rRNA gene sequencing was used to access the salivary microbiota profile. A random forest model was constructed to classify gastric histological types based on the salivary microbiota compositions. A distinct salivary microbiota was observed in patients with GC when comparing with SG and AG, which was featured by an enrichment of putative proinflammatory taxa including Corynebacterium and Streptococcus. Among the significantly decreased oral bacteria in GC patients including Haemophilus, Neisseria, Parvimonas, Peptostreptococcus, Porphyromonas, and Prevotella, Haemophilus, and Neisseria are known to reduce nitrite, which may consequently result in an accumulation of carcinogenic N-nitroso compounds. We found that GC can be distinguished accurately from patients with AG and SG (AUC = 0.91) by the random forest model based on the salivary microbiota profiles, and taxa belonging to unclassified Streptophyta and Streptococcus have potential as diagnostic biomarkers for GC. Remarkable changes in the salivary microbiota functions were also detected across three histological types, and the upregulation in the isoleucine and valine is in line with a higher level of these amino acids in the gastric tumor tissues that reported by other independent studies. Conclusively, bacteria in the oral cavity may contribute gastric cancer and become new diagnostic biomarkers for GC, but further evaluation against independent clinical cohorts is required. The potential mechanisms of salivary microbiota in participating the pathogenesis of GC may include an accumulation of proinflammatory bacteria and a decline in those reducing carcinogenic N-nitroso compounds.

12.
Zootaxa ; 4933(3): zootaxa.4933.3.10, 2021 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-33756793

RESUMO

Two new Mileewini leafhoppers (Hemiptera: Cicadellidae: Mileewinae), Mileewa triloba sp. nov. and Ujna cavipenis sp. nov. are described from Hainan Island, China. Habitus images and figures of both male and female genitalia are provided together with a key to species of Mileewini from Hainan.


Assuntos
Hemípteros , Animais , China , Feminino , Ilhas , Masculino
13.
Int J Stroke ; : 17474930211006285, 2021 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-33724079

RESUMO

BACKGROUND: Observational studies have found an association between visceral adiposity and stroke. AIMS: The purpose of this study was to investigate the role and genetic effect of visceral adipose tissue (VAT) accumulation on stroke and its subtypes. METHODS: In this two-sample Mendelian randomization (MR) study, genetic variants (221 single nucleotide polymorphisms; P<5Ã10-8) using as instrumental variables for MR analysis was obtained from a genome-wide association study (GWAS) of VAT. The outcome datasets for stroke and its subtypes were obtained from the MEGASTROKE consortium (up to 67,162 cases and 453,702 controls). MR standard analysis (inverse variance weighted method) was conducted to investigate the effect of genetic liability to visceral adiposity on stroke and its subtypes. Sensitivity analysis (MR-Egger, weighted median, MR-PRESSO) were also utilized to assess horizontal pleiotropy and remove outliers. Multi-variable MR analysis was employed to adjust potential confounders. RESULTS: In the standard MR analysis, genetically determined visceral adiposity (per 1 SD) was significantly associated with a higher risk of stroke (odds ratio [OR] 1.30; 95% confidence interval [CI] 1.21-1.41, P=1.48Ã10-11), ischemic stroke (OR 1.30; 95% CI 1.20-1.41, P=4.01Ã10-10), and large artery stroke (OR 1.49; 95% CI 1.22-1.83, P=1.16Ã10-4). The significant association was also found in sensitivity analysis and multi-variable MR analysis. CONCLUSIONS: Genetic liability to visceral adiposity was significantly associated with an increased risk of stroke, ischemic stroke, and large artery stroke. The effect of genetic susceptibility to visceral adiposity on the stroke warrants further investigation.

14.
Zhongguo Gu Shang ; 34(3): 282-7, 2021 Mar 25.
Artigo em Chinês | MEDLINE | ID: mdl-33787176

RESUMO

OBJECTIVE: To observe the analgesic effect of manipulation loading on chronic low back pain (CLBP) model rats and the expression of inflammatory factors in psoas major muscle tissue, and to explore the improvement of manipulation on local inflammatory microenvironment. METHODS: Thirty two SPF male SD rats weighing 340-360g were randomly divided into blank group, sham operation group, chronic low back pain model group and treatment group, with 8 rats in each group. In the model group, L4-L6 lumbar vertebrae were implanted with external link fixation system (ELFS). After implantation of ELFS, the treatment group received manualintervention with 5N force and 2Hz frequency on both sides of the spine, 15 min / time, once a day, for 14 consecutive days. Paw with drawl threshold (PWT) and paw withdrawl latency (PWL) was measured before modeling and on the 1st, 3rd, 7th, 10th and 14th day after intervention. At the end of the treatment cycle, the concentrations of calcitonin gene-related peptide (CGRP) and nerve growth factor (NGF) in psoas muscle were detected by enzyme-linked immunosorbent assay (ELISA). RESULTS: There was no significant difference in PWT and PWL between the blank group and the sham operation group after modeling (P>0.05);after modeling, PWT and PWL in the CLBP model group and the treatment group were significantly decreased(P<0.01);PWT in the treatment group was not significantly improved than that in the CLBP model group on the 1st and 3rd day after manual loading(P>0.05);on the 7th day after manual loading, the pain threshold value in the treatment group was higher than that in the CLBP model group, but there was no significant difference There was no significant difference between the two groups (P=0.056>0.05). On the 10th and 14th day of treatment, the mechanical pain threshold of the treatment group began to rise, and it was statistically significant compared with CLBP model rats (P<0.05, P< 0.01);on the 1st and 3rd day after manual treatment, the PWL of the treatment group was not significantly improved compared with CLBP model group (P>0.05);on the 7th day, the PWL of the treatment group was significantly higher than that of CLBP model group, there was statistical significance (P=0.016<0.05). Manual loading improved thermal hyperalgesia in CLBP rats until the end of the experiment. The contents of CGRP and NGF in psoas major muscle of CLBP model group were higher than those of blank group and sham operation group (P<0.01). After treatment, the contents of CGRP and NGF decreased significantly(P<0.01). CONCLUSION: Local massage loading has analgesic effect on CLBP rats, at the same time, it can inhibit the content of CGRP and NGF in psoas muscle tissue of CLBP rats, and improve the local inflammatory microenvironment.


Assuntos
Peptídeo Relacionado com Gene de Calcitonina , Dor Lombar , Animais , Calcitonina , Dor Lombar/terapia , Masculino , Fator de Crescimento Neural/genética , Ratos , Ratos Sprague-Dawley
15.
Orthop Surg ; 2021 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-33783979

RESUMO

OBJECTIVE: To investigate the epidemiological characteristics of major intra-articular fractures. METHODS: This retrospective study enrolled patients with major intra-articular fractures who were treated in the Third Hospital of Hebei Medical University from January 2015 to December 2019. A total of 11,084 patients (7,338 [66.20%] males and 3,746 [33.80%] females) meeting the inclusion and exclusion criteria were included. The distribution characteristics of intra-articular fractures involving shoulder, elbow, wrist, hip, knee, ankle, and subtalar joints were identified.The potential associations between fractures and various other factors, such as age, gender, sites, were explored. RESULTS: There were 74 cases (0.67%) of shoulder fractures, 1,941 cases (17.51%) of elbow fractures, 1,155 cases (10.42%) of wrist fractures, 520 cases (4.69%) of hip fractures, 3,118 cases (28.13%) of knee fractures, 2,156 cases (19.45%) of ankle fractures, and 2,120 cases (19.13%) of subtalar fractures. The overall male-to-female ratio was 1.96:1. The highest proportion age group of major intra-articular fractures included the ages 45-54 years. For males, the highest proportion age group was 45-54 years, for females, it was 55-64 years. The knee joint fracture was the most common type, accounting for 28.13%. For male and female patients, knee fractures accounted for 26.19% and 31.93%, respectively, with a male to female ratio of 1.13:1. The proportion of shoulder fractures was the smallest among this investigation, accounting for 0.67%. For male and female patients, shoulder fractures accounted for 0.44% and 1.12%, respectively, with a male to female ratio of 0.76:1. The age group with the highest proportion of shoulder joint fractures was ≥65 year olds (41.89%), with a male to female ratio of 0.76:1. The age group with the highest risk of elbow, wrist, hip, knee, ankle, and subtalar joint fracture was 5-14 year olds (33.59%) with a male to female ratio of 3.29:1, 5-14 year olds (23.98%) with a male to female ratio of 6.91:1, 45-54 year olds (26.92%) with a male to female ratio of 5.67:1, 45-54 year olds (24.60%) with a male to female ratio of 1.68:1, 25-34 year olds (20.36%) with a male to female ratio of 2.30:1, 45-54 year olds (27.41%) with a male to female ratio of 9.02:1, respectively. The most common site of intra-articular fractures in different age groups was corresponding as follows: 0-4 year olds (elbow), 5-14 year olds (elbow), 15-24 year olds (ankle), 25-34 year olds (subtalar joint), 35-44 year olds (subtalar joint), 45-54 year olds (knee), 55-64 year olds (knee), 65-74 year olds (knee), and ≥75 year olds (knee). CONCLUSION: The current study revealed the age- and gender-specific epidemiological characteristics of major intra-articular fractures, providing a basis for clinical evaluation and practices.

16.
Front Immunol ; 12: 582858, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33679734

RESUMO

The structural and functional destruction of the blood-testis barrier (BTB) following uropathogenic E. coli (UPEC) infection may be a critical component of the pathologic progress of orchitis. Recent findings indicate that the mammalian target of the rapamycin (mTOR)-signaling pathway is implicated in the regulation of BTB assembly and restructuring. To explore the mechanisms underlying BTB damage induced by UPEC infection, we analyzed BTB integrity and the involvement of the mTOR-signaling pathway using in vivo and in vitro UPEC-infection models. We initially confirmed that soluble virulent factors secreted from UPEC trigger a stress response in Sertoli cells and disturb adjacent cell junctions via down-regulation of junctional proteins, including occludin, zonula occludens-1 (ZO-1), F-actin, connexin-43 (CX-43), ß-catenin, and N-cadherin. The BTB was ultimately disrupted in UPEC-infected rat testes, and blood samples from UPEC-induced orchitis in these animals were positive for anti-sperm antibodies. Furthermore, we herein also demonstrated that mTOR complex 1 (mTORC1) over-activation and mTORC2 suppression contributed to the disturbance in the balance between BTB "opening" and "closing." More importantly, rapamycin (a specific mTORC1 inhibitor) significantly restored the expression of cell-junction proteins and exerted a protective effect on the BTB during UPEC infection. We further confirmed that short-term treatment with rapamycin did not aggravate spermatogenic degeneration in infected rats. Collectively, this study showed an association between abnormal activation of the mTOR-signaling pathway and BTB impairment during UPEC-induced orchitis, which may provide new insights into a potential treatment strategy for testicular infection.

17.
mSphere ; 6(2)2021 03 17.
Artigo em Inglês | MEDLINE | ID: mdl-33731468

RESUMO

Bacteria of different shapes have adopted distinct mechanisms to faithfully coordinate morphogenesis and segregate their chromosomes prior to cell division. Despite recent focuses and advances, the mechanism of cell division in ovococci remains largely unknown. Streptococcus suis, a major zoonotic pathogen that causes problems in human health and in the global swine industry, is an elongated and ellipsoid bacterium that undergoes successive parallel splitting perpendicular to its long axis. Studies on cell cycle processes in this bacterium are limited. Here, we report that MsmK (multiple sugar metabolism protein K), an ATPase that contributes to the transport of multiple carbohydrates, has a novel role as a cell division protein in S. suis MsmK can display ATPase and GTPase activities, interact with FtsZ via the N terminus of MsmK, and promote the bundling of FtsZ protofilaments in a GTP-dependent manner in vitro Deletion of the C-terminal region or the Walker A or B motif affects the affinity between MsmK and FtsZ and decreases the ability of MsmK to promote FtsZ protofilament bundling. MsmK can form a complex with FtsZ in vivo, and its absence is not lethal but results in long chains and short, occasionally anuclear daughter cells. Superresolution microscopy revealed that the lack of MsmK in cells leads to normal septal peptidoglycan walls in mother cells but disturbed cell elongation and peripheral peptidoglycan synthesis. In summary, MsmK is a novel cell division protein that maintains cell shape and is involved in the synthesis of the peripheral cell wall.IMPORTANCE Bacterial cell division is a highly ordered process regulated in time and space and is a potential target for the development of antimicrobial drugs. Bacteria of distinct shapes depend on different cell division mechanisms, but the mechanisms used by ovococci remain largely unknown. Here, we focused on the zoonotic pathogen Streptococcus suis and identified a novel cell division protein named MsmK, which acts as an ATPase of the ATP-binding cassette-type carbohydrate transport system. MsmK has GTPase and ATPase activities. In vitro protein assays showed that MsmK interacts with FtsZ and promotes FtsZ protofilament bundling that relies on GTP. Superresolution microscopy revealed that MsmK maintains cell shape and is involved in peripheral peptidoglycan synthesis. Knowledge of the multiple functions of MsmK may broaden our understanding of known cell division processes. Further studies in this area will elucidate how bacteria can faithfully and continually multiply in a constantly changing environment.

18.
Analyst ; 146(7): 2313-2320, 2021 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-33620343

RESUMO

In this study, a facile strategy for the scalable synthesis of cobalt and nitrogen co-doped mesoporous carbon (Co-N/C) is reported. Structural characterization demonstrated that Co and N were successfully co-doped in the highly porous carbon. Graphitization of porous carbon was achieved by the introduction of cobalt species. The degree of graphitization of Co-N/C could be further promoted by increasing the calcination temperature. By taking advantage of the excellent mass and electron transfer kinetics attributed to the high specific surface area, high porosity and high graphitization, the obtained Co-N/C exhibited good electrochemical activity towards H2O2 reduction and excellent sensing performance for the electrochemical detection of H2O2. The Co-N/C-950 catalyst obtained at 950 °C showed good electrochemical sensing performance with a detection limit of 2 µM and a wide linear response over the concentration range from 0.03 mM to 13 mM. Meanwhile, Co-N/C exhibited high selectivity toward the detection of H2O2 in the presence of possible interferences during the applications such as NaCl, glucose, ascorbic acid and so on. The results confirm that Co-N/C could be used as an efficient electrocatalyst to fabricate electrochemical sensing devices.

19.
Artigo em Inglês | MEDLINE | ID: mdl-33522229

RESUMO

Activating upconversion nanoparticle-based photoresponsive nanovectors (UCPNVs) by upconversion visible light at low-power near-infrared (NIR) excitation can realize deeper biotissue stimulation with a minimized overheating effect and photodamage. Here, we demonstrate a facile strategy to construct new surface-decorated UCPNVs based on Passerini three-component reaction (P-3CR) in highly convenient and effective manners. Such UCPNVs materials have a tailored deprotecting wavelength that overlaps upconversion blue light. By using 3-perylenecarboxaldehyde, Tm3+/Yb3+ ion-doped UCNP-containing isocyanides, and antitumor agent chlorambucil as the three components, the resulting monodisperse UCPNV exhibits an efficient release of caged chlorambucil under a very low 976 nm power. This approach expands the synthetic toolbox to enable quick development of UCPNVs for UCNP-assisted low-power NIR photochemistry.

20.
J Am Soc Mass Spectrom ; 32(3): 690-699, 2021 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-33605725

RESUMO

Native mass spectrometry (MS) enables the study of intact proteins as well as noncovalent protein-protein and protein-ligand complexes in their biological state. In this work, we present the application of a Waters desorption electrospray ionization (DESI) source with a prototype spray emitter for rapid surface measurements of folded and native protein structures. A comparison of DESI spray solvent shows that adding 50% methanol to 200 mM ammonium acetate solution does not reduce its performance in preserving folded protein structures. Instead, improved signal-to-noise (S/N) ratio is obtained, and less adducted peaks are detected by using this uncommon native MS solvent system. The standard DESI design with an inlet tube allows optimization of sampling temperature conditions to improve desolvation and therefore S/N ratio. Furthermore, tuning the inlet temperature enables the control and study of unfolding behavior of proteins from surface samples. The optimized condition for native DESI has been applied to several selected proteins and protein complexes with the molecular weight ranging from 8.6 to 66.4 kDa. Ions of folded proteins with narrow charge state distribution (CSD), or peaks showing noncovalent-bond-assembled intact protein complexes, are observed in the spectra. Evidence for the structural refolding of denatured proteins and protein complexes sampled with native solvent highlights the need for care when interpreting DESI native MS data, particularly for proteins with stable native structures.

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