Engineering nanostructured porous SiO2 surfaces for bacteria detection via "direct cell capture"

An optical label-free biosensing platform for bacteria detection ( Escherichia coli K12 as a model system) based on nanostructured oxidized porous silicon (PSiO(2)) is introduced. The biosensor is designed to directly capture the target bacteria cells on its surface with no prior sample processing (such as cell lysis). The optical reflectivity spectrum of the PSiO(2) nanostructure displays Fabry-Pe?rot fringes characteristic of thin-film interference, enabling direct, real-time observation of bacteria attachment within minutes. The PSiO(2) optical nanostructure is synthesized and used as the optical transducer element. The porous surface is conjugated with specific monoclonal antibodies (immunoglobulin G's) to provide the active component of the biosensor. The immobilization of the antibodies onto the biosensor system is confirmed by attenuated total reflectance Fourier transform infrared spectroscopy, fluorescent labeling experiments, and refractive interferometric Fourier transform spectroscopy. We show that the immobilized antibodies maintain their immunoactivity and specificity when attached to the sensor surface. Exposure of these nanostructures to the target bacteria results in "direct cell capture" onto the biosensor surface. These specific binding events induce predictable changes in the thin-film optical interference spectrum of the biosensor. Our preliminary studies demonstrate the applicability of these biosensors for the detection of low bacterial concentrations. The current detection limit of E. coli K12 bacteria is 10(4) cells/mL within several minutes.     

Deciphering the Epigenetic Alphabet Involved in Transgenerational Stress Memory in Crops

Although epigenetic modifications have been intensely investigated over the last decade due to their role in crop adaptation to rapid climate change, it is unclear which epigenetic changes are heritable and therefore transmitted to their progeny. The identification of epigenetic marks that are transmitted to the next generations is of primary importance for their use in breeding and for the development of new cultivars with a broad-spectrum of tolerance/resistance to abiotic and biotic stresses. In this review, we discuss general aspects of plant responses to environmental stresses and provide an overview of recent findings on the role of transgenerational epigenetic modifications in crops. In addition, we take the opportunity to describe the aims of EPI-CATCH, an international COST action consortium composed by researchers from 28 countries. The aim of this COST action launched in 2020 is: (1) to define standardized pipelines and methods used in the study of epigenetic mechanisms in plants, (2) update, share, and exchange findings in epigenetic responses to environmental stresses in plants, (3) develop new concepts and frontiers in plant epigenetics and epigenomics, (4) enhance dissemination, communication, and transfer of knowledge in plant epigenetics and epigenomics.     

Asprich: A novel aspartic acid-rich protein family from the prismatic shell matrix of the bivalve Atrina rigida

Almost all mineralized tissues contain proteins that are unusually acidic. As they are also often intimately associated with the mineral phase, they are thought to fulfill important functions in controlling mineral formation. Relatively little is known about these important proteins, because their acidic nature causes technical difficulties during purification and characterization procedures. Much effort has been made to overcome these problems, particularly in the study of mollusk-shell formation. To date about 16 proteins from mollusk-shell organic matrices have been sequenced, but only two are unusually rich in aspartic and glutamic acids. Here we screened a cDNA library made from the mRNA of the shell-forming cells of a bivalve, Atrina rigida, using probes for short Asp-containing repeat sequences, and identified ten different proteins. Using more specific probes designed from one subgroup of conserved sequences, we obtained the full sequences of a family of seven aspartic acid-rich proteins, which we named "Asprich"; a subfamily of the unusually acidic shell-matrix proteins. Polyclonal antibodies raised against a synthetic peptide of the conserved acidic1 domain of these proteins reacted specifically with the matrix components of the calcitic prismatic layer, but not with those of the aragonitic nacreous layer. Thus the Asprich proteins are constituents of the prismatic layer shell matrix. We can identify different domains within these sequences, including a signal peptide characteristic of proteins destined for extracellular secretion, a conserved domain rich in aspartic acid that contains a sequence very similar to the calcium-binding domain of Calsequestrin, and another domain rich in aspartic acid, that varies between the seven sequences. We also identified a domain with DEAD repeats that may have Mg-binding capabilities. Although we do not know, as yet, the function of these proteins, their generally conserved sequences do indicate that they might well fulfill basic functions in shell formation.     

Should Altruism,Solidarity, or Reciprocity be Used as Prosocial Appeals? Contrasting Conceptions of Members of the General Public and Medical Professionals Regarding Promoting Organ Donation

Moral appeals to altruism as a means to influence people's prosocial behavior are common, especially in organ donation, but communicators might not consider that conceptions of altruism differ among people, cultures, and scholars. In organ donation employing altruism as the main appeal is contested and some propose using solidarity or reciprocity as alternative prosocial appeals. This qualitative study explored views of people from diverse Israeli groups (29 focus groups) and medical professionals (140) regarding the appropriateness of employing these 3 moral appeals in organ donation. The analysis presents frameworks of contrasting conceptions of altruism that point to potential unintended effects when applying a restrictive conception. It also identifies communication challenges associated with introducing solidarity or reciprocity as prosocial and value‐laden persuasive appeals.