Molecular Epidemiology of Echovirus 18 Circulating in Mainland China from 2015 to 2016

Abstract

Echovirus 18 (E18), a serotype of Enterovirus B (EV-B) species, is an important pathogen in aseptic meningitis. E18 had rarely been detected in mainland China, but became the predominant pathogen associated with viral encephalitis (VE) and meningitis in Hebei province for the first time in 2015. To investigate the molecular epidemiology and genetic characteristics of E18 in mainland China, sixteen E18 strains from patient throat swabs with hand, foot, and mouth disease (HFMD) in six provinces in China collected between 2015 and 2016, and four E18 strains isolated from 18 patient cerebrospinal fluid specimens with VE in Hebei Province in 2015 were obtained and sequenced. Combined with the sequences from the GenBank database, we performed an extensive genetic analysis. Phylogenetic analysis of VP1 gene sequences revealed that all E18 strains from mainland China after 2015 belonged to subgenotype C2. There were no obvious specific differences in phylogenetic and variation analyses of E18 genome sequences between HFMD and VE/meningitis strains. Potential multiple recombination may have occurred in the 5′-untranslated region and in the P2 and P3 nonstructural protein-encoding regions of E18 strains from China. The current E18 strains were potential multiple-recombinant viruses. Overall, these findings supported that E18 caused HFMD, VE, and meningitis, although there were no significant associations between clinical features and viral genomic characteristics.

https://ift.tt/2Sh08dr

Novel paper-based electroanalytical tools for food surveillance

Abstract

Analytical strategies to ensure the quality and safety of food products without the need for skilled personnel are highly required. The simplicity of glucose strips for diabetes monitoring should be translated to the agri-food sector, ensuring easy evaluation of certain molecules and/or the freshness of a beverage/foodstuff. In addition to the well-known advantages that are characteristic of electroanalytical methods over other methods, paper-based materials are being used to further reduce the gap between complex laboratory testing and simple point-of-need testing. This article highlights some of the most recent advances in the development of paper-based electrochemical approaches for food surveillance, specifically focusing on the use of novel paper-based materials. Two examples are discussed: the development of a miniaturized biosensor realized on copy paper for the quantification of ethanol in commercial beers, and the measurement of ascorbic acid in food supplements within printed electronics supports. Paper-based materials have the potential to lower economic costs, simplify the operative tasks, and most importantly reduce waste generation. The continued combination of manufacturing methods and functional (smart) materials will facilitate the implementation of food analysis at the point of need.

https://ift.tt/2SfjPm3

Three-dimensional reconstruction of the distribution of elemental tags in single cells using laser ablation ICP-mass spectrometry via registration approaches

Abstract

This paper describes a workflow towards the reconstruction of the three-dimensional elemental distribution profile within human cervical carcinoma cells (HeLa), at a spatial resolution down to 1 μm, employing state-of-the-art laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) instrumentation. The suspended cells underwent a series of fixation/embedding protocols and were stained with uranyl acetate and an Ir-based DNA intercalator. A priori, laboratory-based absorption micro-computed tomography (μ-CT) was applied to acquire a reference frame of the morphology of the cells and their spatial distribution before sectioning. After CT analysis, a trimmed 300 × 300 × 300 μm³ block was sectioned into a sequential series of 132 sections with a thickness of 2 μm, which were subjected to LA-ICP-MS imaging. A pixel acquisition rate of 250 pixels s⁻¹ was achieved, through a bidirectional scanning strategy. After acquisition, the two-dimensional elemental images were reconstructed using the timestamps in the laser log file. The synchronization of the data required an improved optimization algorithm, which forces the pixels of scans in different ablation directions to be spatially coherent in the direction orthogonal to the scan direction. The volume was reconstructed using multiple registration approaches. Registration using the section outline itself as a fiducial marker resulted into a volume which was in good agreement with the morphology visualized in the μ-CT volume. The 3D μ-CT volume could be registered to the LA-ICP-MS volume, consisting of 2.9 × 10⁷ voxels, and the nucleus dimensions in 3D space could be derived.

https://ift.tt/2XfzBRF

Recovery, overloading, and protein interactions in asymmetrical flow field-flow fractionation

Abstract

In asymmetrical flow field-flow fractionation (AF4), similar to other separation techniques, mass recovery and overloading require special attention in order to obtain quantitative results. We conducted a systematic study with five globular proteins of different molecular weight (36.7–669 kDa) and isoelectric point (4.0–6.5), and ultrafiltration membranes that are commonly used in aqueous AF4, regenerated cellulose (RC) and polyethersulfone (PES). Phosphate-buffered saline (PBS) with ionic strength 0.15 M and pH 7.2 was used as the carrier liquid in this study. The actual molecular weight cutoff (MWCO) was found to be higher than the nominal value and varied between membranes of different chemistry but the same nominal MWCO. Adsorption on the membrane was found to be dependent on the membrane chemistry (RC had lower adsorption compared to PES), and independent of the protein standard for the examined proteins. On the other hand, the mass overloading effects (i.e., higher retention times, peak broadening, and fronting peaks) were significantly more pronounced for γ-globulin than for the other proteins. The overloading effects could be rationalized with the increase of the local viscosity close to the membrane, depending on the properties of the proteins, and we derived theoretical equations that related the dependency of the migration velocity on the protein concentration through this non-ideal viscosity effect.

https://ift.tt/2SfjK1J

Do Mechanism-Based Social Explanations Make a Case for Methodological Individualism?

Abstract

Recently, we notice an increasing support for mechanism-based social explanations. Earlier pleas for social mechanisms were often closely linked to defenses of methodological individualism. However, more recent contributions by, e.g., Daniel Little and Petri Ylikoski, seem to be loosening that link and develop a more sophisticated account. In this paper, we review the impact of the social mechanisms approach on methodological individualism and draw conclusions regarding the individualism/holism debate, severing the link between the social mechanisms approach and individualism. Four steps will be taken: (a) there are more than two levels of social explanation; (b) levels of explanation are perspectival, neither absolute, nor unique; (c) seeking microfoundations has value, but so has seeking macrofoundations; (d) there are no general preference rules with respect to the level of social explanations. In conclusion, the answer to the title question is that the social mechanisms approach does not strengthen the case for methodological individualism.

https://ift.tt/2GUPQO9

Incorporation of non-standard amino acids into proteins: challenges, recent achievements, and emerging applications

Abstract

The natural genetic code only allows for 20 standard amino acids in protein translation, but genetic code reprogramming enables the incorporation of non-standard amino acids (NSAAs). Proteins containing NSAAs provide enhanced or novel properties and open diverse applications. With increased attention to the recent advancements in synthetic biology, various improved and novel methods have been developed to incorporate single and multiple distinct NSAAs into proteins. However, various challenges remain in regard to NSAA incorporation, such as low yield and misincorporation. In this review, we summarize the recent efforts to improve NSAA incorporation by utilizing orthogonal translational system optimization, cell-free protein synthesis, genomically recoded organisms, artificial codon boxes, quadruplet codons, and orthogonal ribosomes, before closing with a discussion of the emerging applications of NSAA incorporation.

https://ift.tt/2SQOtHq

Efficacy of Intraperitoneal Instillation of Bupivacaine after Bariatric Surgery: Randomized Controlled Trial

Abstract

Introduction

Obesity is one of the greatest health problems. Bariatric surgery is more effective than non-surgical options; however, postoperative pain is bound to a greater morbidity. Control of postoperative pain is important in facilitating patient convalescence. In this study, we assessed the efficacy of intraperitoneal instillation of bupivacaine after bariatric surgery.

Methods

A hundred patients who underwent bariatric procedures including sleeve gastrectomy, sleeve gastrectomy with cardioplasty, gastric bypass, and gastric mini bypass (one anastomosis gastric bypass) were included in the study. Patients were divided into two groups randomly, 50 patients for each; group I had intraperitoneal instillation of 40 ml bupivacaine 0.25% at the end of the procedure, while group II had normal saline instillation. Monitoring of pain control in the first 24 h after surgery was done using the visual analogue scale (VAS) to assess the efficacy of intraperitoneal bupivacaine instillation and its effect on the overall opioid usage, postoperative nausea and vomiting (PONV), and shoulder tip pain.

Results

Pain scores were significantly lower in group I compared to group II at recovery, 2, 4 and 6 h after surgery, P = 0.004, 0.001, < 0.001, and 0.001 respectively. However, there were no significant differences between 12 and 24 h postoperatively. Additionally, there was a significant difference regarding the need for rescue analgesia at recovery P = < 0.001^*. Further analysis revealed lower morphine consumption via PCA in group I compared to group II P = 0.013^*. There were no significant differences with the use of intraperitoneal bupivacaine as regards nausea, vomiting, or shoulder tip pain, P = 0.688, 0.249, and 0.487, respectively.

Conclusions

Intraperitoneal instillation of bupivacaine provides a good analgesia in the early postoperative period, reduces the overall consumption of opioid, and decreases the rescue analgesia requirement in the first 24 h after surgery.

https://ift.tt/2twYz19