Abstract: Designer self-assembling peptides are a category of emerging nanobiomaterials which have been widely investigated in the past decades. In this field, amphiphilic peptides have received special attention for their simplicity in design and versatility in application. This review focuses on recent progress in designer amphiphilic peptides, trying to give a comprehensive overview about this special type of self-assembling peptides. By exploring published studies on several typical types of amphiphilic peptides in recent years, herein we discuss in detail the basic design, self-assembling behaviors and the mechanism of amphiphilic peptides, as well as how their nanostructures are affected by the peptide characteristics or environmental parameters. The applications of these peptides as potential nanomaterials for nanomedicine and nanotechnology are also summarized. Keywords: amphiphilic peptides, self-assembly, nanomaterials
Functional coating materials have found broad technological applications in diverse fields. Despite recent advances, few coating materials simultaneously achieve robustness and substrate independence while still retaining the capacity for genetically encodable functionalities. Here, we report Escherichia coli biofilm-inspired protein nanofiber coatings that simultaneously exhibit substrate independence, resistance to organic solvents, and programmable functionalities. The intrinsic surface adherence of CsgA amyloid proteins, along with a benign solution-based fabrication approach, facilitates forming nanofiber coatings on virtually any surface with varied compositions, sizes, shapes, and structures. In addition, the typical amyloid structures endow the nanofiber coatings with outstanding robustness. On the basis of their genetically engineerable functionality, our nanofiber coatings can also seamlessly participate in functionalization processes, including gold enhancement, diverse protein conjugations, and DNA binding, thus enabling a variety of proof-of-concept applications, including electronic devices, enzyme immobilization, and microfluidic bacterial sensors. We envision that our coatings can drive advances in electronics, biocatalysis, particle engineering, and biomedicine.
This paper analyzes the contents of medical person evaluation,designs a medical ethics evaluation system based on B/S structure.It introduces the functions of the system in detail,and describes the design and implementation.
The interaction between extracellular matrices and cancer cells plays an important role in regulating cancer cell behaviors. In this article, we use matrigel to mimic extracellular matrices and investigate experimentally how matrigel influences the shape and dynamics of breast cancer cells (MDA-MB-231-GFP cells). We find that matrigel facilitates cancer cells’ migration and shape deformation. The influences of the matrigel concentration are also reported.
Significance Voltage-gated proton (Hv1) channels play important roles in various physiological processes, such as the innate immune response. However, the mechanism by which this channel closes and opens its proton permeation pathways is unknown, due to the lack of structural information about the closed and open states of the channel. This study uses both simulation and experimental approaches to develop models of the closed and open states of the Hv1 channel. These models suggest a mechanism for how the channel closes and opens. The models also suggest a mechanism explaining why a blocker only binds to the open state of the channel. These structural models will be essential for future investigations of this channel and the development of new pharmacological blockers.
Purinergic signaling plays distinct and important roles in the CNS, including the transmission of calcium signals between astrocytes. Gap junction hemichannels are among the mechanisms proposed by which astrocytes might release ATP; however, whether the gap junction protein connexin43 (Cx43) forms these “hemichannels” remains controversial. Recently, a new group of proteins, the pannexins, have been shown to form nonselective, high-conductance plasmalemmal channels permeable to ATP, thereby offering an alternative for the hemichannel protein. Here, we provide strong evidence that, in cultured astrocytes, pannexin1 (Panx1) but not Cx43 forms hemichannels. Electrophysiological and fluorescence microscope recordings performed in wild-type and Cx43-null astrocytes did not reveal any differences in hemichannel activity, which was mostly eliminated by treating Cx43-null astrocytes with Panx1-short interfering RNA [Panx1-knockdown (Panx1-KD)]. Moreover, quantification of the amount of ATP released from wild-type, Cx43-null, and Panx1-KD astrocytes indicates that downregulation of Panx1, but not of Cx43, prevented ATP release from these cells.
In the prevailing phenomenon of peptide fibrillization, β-strand conformation has long been believed to be an important structural basis for peptide assembly. According to a widely accepted theory, in most peptide fibrillization processes, peptide monomers need to intrinsically take or transform to β-strand conformation before they can undergo ordered packing to form nanofibers. In this study, we reported our findings on an alternative peptide fibrillization pathway starting from a disordered secondary structure, which could then transform to β-strand after fibrillization. By using circular dichroism, thioflavin-T binding test, and transmission electron microscopy, we studied the secondary structure and assembly behavior of Ac-RADARADARADARADA-NH2 (RADA16-I) in a low concentration range. The effects of peptide concentration, solvent polarity, pH, and temperature were investigated in detail. Our results showed that at very low concentrations, even though the peptide was in a disordered secondary structure, it could still form nanofibers through intermolecular assembly, and under higher peptide concentrations, the transformation from the disordered structure to β-strand could happen with the growth of nanofibers. Our results indicated that even without ordered β-strand conformation, driving forces such as hydrophobic interaction and electrostatic interaction could still play a determinative role in the self-assembly of peptides. At least in some cases, the formation of β-strand might be the consequence rather than the cause of peptide fibrillization.
The hemoglobin, albumin, lymphocyte, and platelet (HALP) score, neutrophil-to-lymphocyte ratio (NLR), and platelet-to-lymphocyte ratio (PLR) are the important prognostic markers in some tumor types. This study aimed to evaluate the prognostic impact of pretreatment using HALP, NLR, and PLR for patients with small-cell lung cancer (SCLC), who were undergoing chemotherapy.In this retrospective study, 335 patients with SCLC were included between 2016 and 2018. The cutoff values for HALP, NLR, and PLR were defined using X-tile software. Survival was analyzed by the Kaplan-Meier method, with differences analyzed through the log-rank test. The multivariate Cox proportional hazard model was used to evaluate the prognostic significance of HALP, NLR, and PLR for SCLC.The median follow-up period was 27.1 months (range: 0.5-46.2 months). Based on the Kaplan-Meier curve analysis, it was noticed that the low pretreatment HALP (≤18.6), high pretreatment NLR (>2.4), and high PLR (>191.6) were significantly associated with worse overall survival (OS) (P = 0.009, 0.001, and 0.033, respectively). Cox multivariate analysis demonstrated that low pretreatment HALP and high pretreatment NLR were the independent prognostic factors for worse OS (hazard ratio [HR] = 1.468, 95% confidence interval [CI]: 1.004-2.146, P = 0.047; HR = 0.722, 95% CI: 0.542-0.960, P = 0.025, respectively).HALP and NLR were the independent prognostic factors of OS for SCLC patients undergoing chemotherapy.
To investigate the expression of tripartite-motif protein 25 (TRIM25) and pyruvate kinase M2 (PKM2) protein in non-small cell lung cancer (NSCLC) and explore their role in the occurrence and progression of NSCLC.The expressions of TRIM25 and PKM2 protein were detected in 60 NSCLC specimens and 20 adjacent normal lung tissue (>5 cm from the lesions) with immunofluorescence histochemical method and in 10 fresh specimens of NSCLC with Western blotting. The results were analyzed in relation with the clinicopathological features of the patients.The positivity rates of TRIM25 expression was 45% in the 60 lung carcinoma specimens, significantly higher than that in the 20 normal lung tissues (10%, P=0.005). TRIM25 protein was expressed in 28.6% of lung adenocarcinoma tissues and in 59.4% of squamous carcinoma tissues (P=0.017). TRIM25 protein expression was positively correlated with the TNM stages and lymph node metastasis of NSCLC (P<0.05). The expressions of PKM2 protein in 60 cases of lung carcinoma was 73.3%,while in 20 cases of normal lung tissues the expressions was 30%(P=0.001). The positivity rates of PKM2 expression differed significantly between lung adenocarcinoma and squamous carcinoma (57.1% vs 87.5%, P=0.008). An inverse correlation was noted between TRIM25 and PKM2 expressions (P=0.026).TRIM25 and PKM2 protein may participate in the occurrence and progression of NSCLC, and their expressions are inversely correlated.
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