Polyester Sulphonic Acid Interstitial Nanocomposite Platform for Peroxide Biosensor

A novel enzyme immobilization platform was prepared on a platinum disk working electrode by polymerizing aniline inside the interstitial pores of polyester sulphonic acid sodium salt (PESA). Scanning electron microscopy study showed the formation of homogeneous sulphonated polyaniline (PANI) nanotubes (∼90 nm) and thermogravimetric analysis (TGA) confirmed that the nanotubes were stable up to 230 °C. The PANI:PESA nanocomposite showed a quasi-reversible redox behaviour in phosphate buffer saline. Horseradish peroxidase (HRP) was immobilized on to this modified electrode for hydrogen peroxide detection. The biosensor gave a sensitivity of 1.33 μA (μM)-1 and a detection limit of 0.185 μM for H2O2. Stability experiments showed that the biosensor retained more than 64% of its initial sensitivity over four days of storage at 4 °C

Application Of FBG Optical Sensors To In-Situ Monitoring The Thermo-Mechanical Behaviour Of Cold Spray Coated Samples

In this research, a fiber Bragg grating (FBG) sensor is employed for monitoring thermal and mechanical strain induced by severe plastic deformation during high thermal and mechanical strain rate of cold spray technique. The FBG sensors are embedded in magnesium alloy substrates and the strain evolutions of the substrates are recorded during the cold gas spray coating process. In these experiments, the localized transient thermo-mechanical strain induced in the close vicinity of the substrate surface is monitored. Qualitative analysis of the complicated spectra shapes obtained during coating and cooling processes demonstrates the repeatability and sensitivity of the sensors in this condition. In addition, the obtained result from FBG sensors reveals the existence of compressive strain in the substrate near the interface during peening; however, it is released after a few second because of the high impact temperature of cold spray coating

Prediabetes management in the Middle East, Africa and Russia: Current status and call for action:

Most data on the burden of diabetes and prediabetes are from countries where local infrastructure can support reliable estimates of the burden of non-communicable diseases. Countries in the Middle ..

Vision, challenges and opportunities for a Plant Cell Atlas

With growing populations and pressing environmental problems, future economies will be increasingly plant-based. Now is the time to reimagine plant science as a critical component of fundamental science, agriculture, environmental stewardship, energy, technology and healthcare. This effort requires a conceptual and technological framework to identify and map all cell types, and to comprehensively annotate the localization and organization of molecules at cellular and tissue levels. This framework, called the Plant Cell Atlas (PCA), will be critical for understanding and engineering plant development, physiology and environmental responses. A workshop was convened to discuss the purpose and utility of such an initiative, resulting in a roadmap that acknowledges the current knowledge gaps and technical challenges, and underscores how the PCA initiative can help to overcome them.</jats:p

Aquaporin contribution to facilitated membrane diffusion of hydrogen peroxide and cations in plant cells

Aquaporins (AQPs) are channels facilitating the diffusion of water and small solutes across the cellular membranes. Recent evidence suggests that plant AQPs also facilitate the rapid permeation of hydrogen peroxide (H2O2) and even cations, which are essential for plant physiology. In our project, we aim at establishing molecular and cellular tools to determine whether plasma membrane AQPs (PIPs, plasma membrane intrinsic proteins) facilitate the diffusion of H2O2 and cations through the plasma membrane in plant cells and characterize this transport. We prepared genetic constructs to stably co-express in Nicotiana tabacum BY2 suspension cells the fluorescent H2O2 sensor HyPer, with maize PIP2;5, an AQP that, when expressed in yeast, facilitates the membrane diffusion of H2O2. PIP2;5 expression was controlled by a heat shock inducible promoter. After induction of PIP2;5 expression, a HyPer signal was recorded when the cells were incubated with H2O2, which suggests that PIP2;5 facilitates H2O2 transmembrane diffusion. Using this new system, we tested several maize and Arabidopsis PIP2s and showed that they facilitate the H2O2 transmembrane diffusion, but it was not the case for the PIP2;5W85A mutant. We also showed that treatment by abscisic acid and the elicitor flagellin-derived flg22 peptide induced the intracellular H2O2 accumulation in plant cells when PIP2;5 was expressed. These results indicate that plant suspension cells and the HyPer sensor co-expressed with PIPs are a powerful toolkit for evaluating the transport specificity of PIPs in living cells, determining their molecular determinants as well as real-time monitoring H2O2 dynamics in plant single cells. The cation transport ability of PIP2;5 was first tested in a yeast expression system. PIP2;5 increased the Na+ sensitivity of the cells compared with the control yeast. We confirmed this result in BY2 cells using a novel fluorescent photo-switchable Li+ sensor. After induction of PIP2;5 expression and incubation with the sensor and Li+, a higher fluorescent signal was observed compared with the signal obtained in non-induced BY2 cells, suggesting that PIP2;5 facilitates the membrane diffusion of cations. Furthermore, this new feature was tested in intact maize plants deregulated in PIP2;5 expression. The results obtained from PIP2;5 deregulated plants support our conclusion that PIP2;5 is a novel cation channel or a cation transport facilitator.(SC - Sciences) -- UCL, 202

Plant aquaporins: crossroads of hydrogen peroxide signaling

Reactive oxygen species (ROS), including hydrogen peroxide (H2O2), are important inter- and intracellular signaling molecules involved in various plant physiological processes under biotic and abiotic stress conditions. They are produced in different subcellular compartments such as apoplast, plasma membrane, chloroplasts, peroxisomes, and mitochondria. Under stress, H2O2 is mainly produced in the apoplast by plasma membrane localized respiratory oxygen burst oxidase homologs (RBOHs), dismutases, and cell wall peroxidases. The function of H2O2 as a signal requires its diffusion through the plasma membrane or internal membranes, a process that is facilitated by the presence of channels named aquaporins (AQPs). In this chapter, we will discuss the mechanisms by which AQPs facilitate and regulate H2O2 membrane diffusion, and the relevance of their contribution in organellar, cellular, and cell-to-cell H2O2 signaling processes in the context of abiotic and biotic stresses

Evolutionary and Predictive Functional Insights into the Aquaporin Gene Family in the Allotetraploid Plant Nicotiana tabacum

Aquaporins (AQPs) are a class of integral membrane proteins that facilitate the membrane diffusion of water and other small solutes. Nicotiana tabacum is an important model plant, and its allotetraploid genome has recently been released, providing us with the opportunity to analyze the AQP gene family and its evolution. A total of 88 full-length AQP genes were identified in the N. tabacum genome, and the encoding proteins were assigned into five subfamilies: 34 plasma membrane intrinsic proteins (PIPs); 27 tonoplast intrinsic proteins (TIPs); 20 nodulin26-like intrinsic proteins (NIPs); 3 small basic intrinsic proteins (SIPs); 4 uncharacterized X intrinsic proteins (XIPs), including two splice variants. We also analyzed the genomes of two N. tabacum ancestors, Nicotiana tomentosiformis and Nicotiana sylvestris, and identified 49 AQP genes in each species. Functional prediction, based on the substrate specificity-determining positions (SDPs), revealed significant differences in substrate specificity among the AQP subfamilies. Analysis of the organ-specific AQP expression levels in the N. tabacum plant and RNA-seq data of N. tabacum bright yellow-2 suspension cells indicated that many AQPs are simultaneously expressed, but differentially, according to the organs or the cells. Altogether, these data constitute an important resource for future investigations of the molecular, evolutionary, and physiological functions of AQPs in N. tabacum

Computational Analysis of Damaging Single-Nucleotide Polymorphisms and Their Structural and Functional Impact on the Insulin Receptor

Single-nucleotide polymorphisms (SNPs) associated with complex disorders can create, destroy, or modify protein coding sites. Single amino acid substitutions in the insulin receptor (INSR) are the most common forms of genetic variations that account for various diseases like Donohue syndrome or Leprechaunism, Rabson-Mendenhall syndrome, and type A insulin resistance. We analyzed the deleterious nonsynonymous SNPs (nsSNPs) in INSR gene based on different computational methods. Analysis of INSR was initiated with PROVEAN followed by PolyPhen and I-Mutant servers to investigate the effects of 57 nsSNPs retrieved from database of SNP (dbSNP). A total of 18 mutations that were found to exert damaging effects on the INSR protein structure and function were chosen for further analysis. Among these mutations, our computational analysis suggested that 13 nsSNPs decreased protein stability and might have resulted in loss of function. Therefore, the probability of their involvement in disease predisposition increases. In the lack of adequate prior reports on the possible deleterious effects of nsSNPs, we have systematically analyzed and characterized the functional variants in coding region that can alter the expression and function of INSR gene. In silico characterization of nsSNPs affecting INSR gene function can aid in better understanding of genetic differences in disease susceptibility

Vision, challenges and opportunities for a Plant Cell Atlas

With growing populations and pressing environmental problems, future economies will be increasingly plant-based. Now is the time to reimagine plant science as a critical component of fundamental science, agriculture, environmental stewardship, energy, technology and healthcare. This effort requires a conceptual and technological framework to identify and map all cell types, and to comprehensively annotate the localization and organization of molecules at cellular and tissue levels. This framework, called the Plant Cell Atlas (PCA), will be critical for understanding and engineering plant development, physiology and environmental responses. A workshop was convened to discuss the purpose and utility of such an initiative, resulting in a roadmap that acknowledges the current knowledge gaps and technical challenges, and underscores how the PCA initiative can help to overcome them