Plasmonic probing of the adhesion strength of single microbial cells

Probing the binding between a microbe and surface is critical for understanding biofilm formation processes, developing biosensors, and designing biomaterials, but it remains a challenge. Here, we demonstrate a method to measure the interfacial forces of bacteria attached to the surface. We tracked the intrinsic fluctuations of individual bacterial cells using an interferometric plasmonic imaging technique. Unlike the existing methods, this approach determined the potential energy profile and quantified the adhesion strength of single cells by analyzing the fluctuations. This method provides insights into biofilm formation and can also serve as a promising platform for investigating biological entity/surface interactions, such as pathogenicity, microbial cell capture and detection, and antimicrobial interface screening.

Microorganisms can form biofilms, which are widely distributed and present on biotic and abiotic surfaces in natural, industrial, and medical settings (1–3). Initial bacterial adhesion to surfaces is the most crucial step in biofilm formation. The transition from initial weak, reversible interactions between a bacterium and a surface to irreversible adhesion involves complex physicochemical forces, including specific receptor-ligand forces, nonspecific hydrophobic, and electrostatic forces (4). Understanding and managing bacterial adhesion, especially at single-cell level, is a cross-disciplinary challenge (5, 6).While many methods have been developed for study of bacterial adhesion, most technologies are based on ensemble analysis of a vast population of cells, which washes out heterogeneity and microscopic information of single bacterial cells, and cannot measure the forces driving cell adhesion. Several methods are now available to study bacterial adhesion at the single-cell level (7–9). For example, atomic force microscopy (AFM) measures interfacial forces by mechanically moving one cell with the AFM probe (7, 10). Optical tweezers are another force spectroscopy method with an intense laser field that uses microbeads attached to the cell (11, 12). These methods measure one single cell at one time, thus having limited throughput. Additionally, they exert external forces on the cell and interfere with the intrinsic feature of bacterial adhesion.Here, we aim to probe the interfacial forces by measuring intrinsic fluctuations of bacteria attached to the surface using plasmonic interferometric imaging technique. Unlike AFM or optical tweezers, this method enabled us to perform high-throughput tracking of many single bacterial cells, to determine the potential energy profile for each bacterial cell and obtain the elastic parameters. To probe the tiny vertical fluctuations, we imaged the interferometric pattern of bacterial cells scattering the planar plasmonic wave propagating on the surface. The plasmonic scattering intensity was extremely sensitive to the vertical distance, allowing precise tracking of the fluctuations. From the fluctuation analyses, we obtained the interfacial energy profiles and elasticity of microbial binding, which were essential properties in understanding microbial adhesion. The derived binding constant can be used to quantify bacterial adhesion strength. Thus, the knowledge obtained can help understand biofilm formation and be used in the design of artificial surfaces to minimize or maximize bacterial adhesion.     

Carboxymethylcellulose ammonium-derived nitrogen-doped carbon fiber/molybdenum disulfide hybrids for high-performance supercapacitor electrodes

In this paper, a new type of nitrogen-doped carbon fiber/molybdenum disulfide (N-CFs/MoS₂) hybrid electrode materials are prepared via a certain concentration in solvothermal synthesis followed by a high-temperature carbonization process and using the carboxymethylcellulose ammonium (CMC-NH₄) as a structure-directing agent for MoS₂ nanosheet growth during the solvothermal synthesis process. The addition of CMC-NH₄ effectively prevents the agglomeration of MoS₂ nanosheets to increase the specific surface area. Moreover, it not only serves as a carbon source to provide conductive pathways, but also introduces N atoms to improve the conductivity of the CFs and promote the transfer of electrons and ions. This ultimately increases the conductivity of the electrode materials. Thus, the as-prepared N-CFs/MoS₂ hybrids exhibit excellent electrochemical performance. The specific capacitance is up to 572.6 F g⁻¹ under a current density of 0.75 A g⁻¹ and the specific capacitance retained 98% of the initial capacitance after 5000 cycles of charge–discharge tests at a current density of 2.5 A g⁻¹. Moreover, the hybrids show a maximum energy density of 19.5 W h kg⁻¹ at a power density of 94 W kg⁻¹. Therefore, the as-prepared N-CFs/MoS₂ hybrids with remarkable electrochemical properties, low cost and environment protection show potential for practical application in the development of high-performance electrochemical energy storage devices.

Novel CMC-NH₄-derived nitrogen-doped CFs/MoS₂ hybrid electrode materials are prepared using CMC-NH₄ as a structure-directing agent for MoS₂ nanosheets.     

还原型谷胱甘肽片质量标准提高工作研究

目的:对还原型谷胱甘肽片质量标准进行提高:改进鉴别方法,建立有关物质、溶出度和含量测定的方法。方法:采用反相高效液相色谱法,色谱柱用VenusiL MP C₁₈(4.6 mm×250 mm,5μm),流动相为磷酸盐溶液-甲醇(96:4),检测波长210nm。结果:还原型谷胱甘肽在5~1034μg·mL^-1浓度范围内线性关系良好(r=1.0000,n=7),平均回收率为99.0%,RSD=0.6%。结论:标准修订提高后,可更好地用于该制剂的质量控制。     

苦参片质量标准的研究

目的：修订完善苦参片的质量标准。方法：修订现行标准的显微鉴别和薄层鉴别;增订高效液相色谱法测定苦参片中苦参碱和氧化苦参碱的总量。结果：显微鉴别中苦参组织特征均易察见;薄层色谱中斑点清晰,专属性强;苦参碱,氧化苦参碱分别在24.2～4840μg（r=0.9999）、20.8～4160μg（r=0.9999）范围内线性关系良好,平均回收率分别为97.53%（RSD为1.17%）、96.97%（RSD为1.35%）。结论：修订后的标准简便、准确,可用于苦参片的质量控制。     

NAc Shell Arc/Arg3.1 Protein Mediates Reconsolidation of Morphine CPP by Increased GluR1 Cell Surface Expression: Activation of ERK-Coupled CREB is Required

Background:

Relapse into drug abuse evoked by reexposure to the drug-associated context has been a primary problem in the treatment of drug addiction. Disrupting the reconsolidation of drug-related context memory would therefore limit the relapse susceptibility.

Methods:

Morphine conditioned place preference (CPP) was used to assess activity-regulated cytoskeleton-associated protein (Arc/Arg3.1) and correlative molecule expression in the Nucleus accumbens (NAc) shell during the reconsolidation of morphine CPP. U0126 and Arc/Arg3.1 antisense oligodeoxynucleotide were adapted to evaluate the role and the underlying mechanism of Arc/Arg3.1 during the reconsolidation.

Results:

The retrieval of morphine CPP in rats specifically increased the Arc/Arg3.1 protein level in the NAc shell, accompanied simultaneously by increases in the phosphorylation of extracellular signal-regulated kinase1/2 (pERK1/2), the phosphorylation of Cyclic Adenosine monophosphate (cAMP) response element-binding (pCREB), and the up-regulation of the membrane α-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) receptors GluR1 subunit level. Intra-NAc shell infusion U0126, an inhibitor of the Mitogen-activated protein kinase kinase (MEK), prevented the retrieval-induced up-regulation of pERK1/2, pCREB, Arc/Arg3.1, and membrane GluR1 immediately after retrieval of morphine CPP. The effect of disrupting the reconsolidation of morphine CPP by U0126 could last for at least 14 days, and could not be evoked by a priming injection of morphine. Furthermore, the specific knockdown of Arc/Arg3.1 in the NAc shell decreased the membrane GluR1 level, and impaired both the reconsolidation and the reinstatement of morphine CPP.

Conclusions:

Arc/Arg3.1 in the NAc shell mediates the reconsolidation of morphine-associated context memory via up-regulating the level of membrane of GluR1, for which the local activation of the ERK-CREB signal pathway, as an upstream mechanism of Arc/Arg3.1, is required.     

A rare asymptomatic metallic intraocular foreign body retained in the anterior chamber for 15 years: A case report

Rationale:Intraocular foreign bodies (IOFBs) are common in ocular injuries, but asymptomatic metallic IOFBs retained in the anterior chamber for years are rare.Patient concerns:A 31-year-old female presented with blurred vision in her right eye after lumbar magnetic resonance imaging. Her best-corrected vision acuity was 0.6 in the right eye and 1.0 in the left eye. Slit-lamp examination revealed a brown granular foreign body in the anterior chamber and pigmentation of the limbus. Lens and retina examination indicated ocular siderosis. Corneal endothelioscopy revealed decreased endothelial cell density. A detailed history showed ocular globe injury 15 years earlier.Diagnoses:Anterior chamber IOFB with ocular siderosis.Interventions:Anterior chamber foreign body removal was performed with appropriate incision and forceps.Outcomes:The anterior chamber IOFB was successfully removed and examined as a magnetic metal foreign body. The best-corrected vision acuity was 1.0 at 1 day postoperatively. An abnormal electroretinogram with a 12% decrease in the “b” wave and a 91% decrease in the “a” wave was observed 3 months postoperatively. There were no intraoperative or postoperative complications during a 3-month follow-up.Lessons:Eye trauma should be examined carefully to exclude IOFBs. Asymptomatic anterior chamber foreign bodies can also cause corneal endothelial injury and ocular siderosis. Careful examination and timely management are needed in such cases.     

Efficacy and safety of acupuncture combined with analgesics on lung cancer pain: A protocol for systematic review and meta-analysis

Background:Lung cancer (LC) is the malignant tumor with the highest incidence in the world, and treatment methods include surgery, radiotherapy, chemotherapy, and immunotherapy. Cancer pain is a common symptom in patients with LC, and the clinical treatment is to relieve it with analgesics. Acupuncture can relieve cancer pain. This study aims to systematically study the efficacy and safety of acupuncture combined with analgesics on cancer pain in patients with LC.Methods:From the beginning to April 2021, search Medline, Embase, Cochrane Central Controlled Trials Register (Central), China National Knowledge Infrastructure (CNKI), Wanfang Database, China Biomedical Literature Database (CBM), and Chinese Science Journal Database (VIP database). Search the international clinical trial registration platform and the Chinese clinical trial registration platform to find ongoing or unpublished trials. The main outcome indicator is the total effective rate of analgesia, and the secondary outcome indicator is pain intensity score and adverse reactions. The RevMan 5.4 software will be used for statistical analysis.Results:This study will provide the latest evidence for acupuncture combined with analgesics to relieve LC pain.Conclusion:The conclusion of this study is to evaluate the effectiveness and safety of acupuncture combined with analgesics in alleviating LC pain.INPLASY registration number:INPLASY202150051     

Whether cognitive behavioral therapy is effective for Alzheimer's disease: A protocol for systematic review and network meta-analysis

Background:Alzheimer disease (AD) is a progressive neurodegenerative disease characterized by impaired memory and cognitive judgment. It is the leading cause of dementia in the elderly, and its high morbidity and mortality have also brought a significant social burden. So far, there is no method can completely cure Alzheimer''s dementia, but there are many non-drug treatments that have been praised by people, especially the cognitive behavioral therapy proposed in recent years. The main purpose of this article is to evaluate the effect of cognitive behavioral therapy on the cognitive function improvement of patients with Alzheimer''s dementia.Methods:We did a network meta-analysis to identify both direct and indirect evidence in relevant studies. A systematic literature search will be performed in the Cochrane Library, PubMed, and EMBASE from inception to October 2020. We extracted the relevant information from these trials with a predefined data extraction sheet and assessed the risk of bias with the Cochrane risk of bias tool.The outcomes investigated were Mini–Mental State Examination and AD Assessment Scale-Cognitive section scores. We did a pair-wise meta-analysis using the fixed-effects model and then did a random-effects network meta-analysis within a Bayesian framework. The = the Assessment of Multiple Systematic Reviews-2 scale, Preferred Reporting Items for Systematic Reviews and Meta-Analyses scale and Grading of Recommendations Assessment, Development and Evaluation were used to assess the quality and evidence grade of the literature. General characteristics of the eligible randomized controlled trials will be summarized and described. Meanwhile, The ADDIS software will be used to perform the network meta-analysis, and the result figures will be generated by STATA 15.0 software.Results:Using the draft search strategy of databases and after screening,7 randomized controlled trials met the a priori criteria and were included. This network mate-analysis will be published in a peer-reviewed journal.Conclusion:Our study will provide evidence for cognitive behavioral intervention in AD patients. And provide recommendations and guidelines for the clinic.Protocol Registration:INPLASY2020110052.     

An integrated pathway interaction network for the combination of four effective compounds from ShengMai preparations in the treatment of cardio-cerebral ischemic diseases

Aim:

SMXZF (a combination of ginsenoside Rb1, ginsenoside Rg1, schizandrin and DT-13) derived from Chinese traditional medicine formula ShengMai preparations) is capable of alleviating cerebral ischemia-reperfusion injury in mice. In this study we used network pharmacology approach to explore the mechanisms of SMXZF in the treatment of cardio-cerebral ischemic diseases.

Methods:

Based upon the chemical predictors, such as chemical structure, pharmacological information and systems biology functional data analysis, a target-pathway interaction network was constructed to identify potential pathways and targets of SMXZF in the treatment of cardio-cerebral ischemia. Furthermore, the most related pathways were verified in TNF-α-treated human vascular endothelial EA.hy926 cells and H2O2-treated rat PC12 cells.

Results:

Three signaling pathways including the NF-κB pathway, oxidative stress pathway and cytokine network pathway were demonstrated to be the main signaling pathways. The results from the gene ontology analysis were in accordance with these signaling pathways. The target proteins were found to be associated with other diseases such as vision, renal and metabolic diseases, although they exerted therapeutic actions on cardio-cerebral ischemic diseases. Furthermore, SMXZF not only dose-dependently inhibited the phosphorylation of NF-κB, p50, p65 and IKKα/β in TNF-α-treated EA.hy926 cells, but also regulated the Nrf2/HO-1 pathway in H2O2-treated PC12 cells.

Conclusion:

NF-κB signaling pathway, oxidative stress pathway and cytokine network pathway are mainly responsible for the therapeutic actions of SMXZF against cardio-cerebral ischemic diseases.