Structural and Functional Modifications of Corneal Crystallin ALDH3A1 by UVB Light

As one of the most abundantly expressed proteins in the mammalian corneal epithelium, aldehyde dehydrogenase 3A1 (ALDH3A1) plays critical and multifaceted roles in protecting the cornea from oxidative stress. Recent studies have demonstrated that one protective mechanism of ALDH3A1 is the direct absorption of UV-energy, which reduces damage to other corneal proteins such as glucose-6-phosphate dehydrogenase through a competition mechanism. UV-exposure, however, leads to the inactivation of ALDH3A1 in such cases. In the current study, we demonstrate that UV-light caused soluble, non-native aggregation of ALDH3A1 due to both covalent and non-covalent interactions, and that the formation of the aggregates was responsible for the loss of ALDH3A1 enzymatic activity. Spectroscopic studies revealed that as a result of aggregation, the secondary and tertiary structure of ALDH3A1 were perturbed. LysC peptide mapping using MALDI-TOF mass spectrometry shows that UV-induced damage to ALDH3A1 also includes chemical modifications to Trp, Met, and Cys residues. Surprisingly, the conserved active site Cys of ALDH3A1 does not appear to be affected by UV-exposure; this residue remained intact after exposure to UV-light that rendered the enzyme completely inactive. Collectively, our data suggest that the UV-induced inactivation of ALDH3A1 is a result of non-native aggregation and associated structural changes rather than specific damage to the active site Cys

Determination of the efficacy of ultrasound combined with essential oils on the decontamination of Salmonella inoculated lettuce leaves

Salmonella is one of main pathogenic bacteria present in fresh produce. Ultrasound has been reported to be effective at inactivating food-borne pathogens. Moreover, ultrasound can be combined with essential oils to enhance its efficacy. This study evaluates the reduction and inactivation of Salmonella enterica Abony inoculated on lettuce leaves by the application of continuous and pulsed ultrasound as well as ultrasound combined with the essential oil of oregano and thyme. The physicochemical properties of these essential oil nanoemulsions are characterised while the structural damage of treated leaves is determined by the electrolyte leakage. Ultrasound combined with essential oils enhanced the microbial reduction on lettuce leaves and inactivation on the treated water, resulting on significant differences at concentrations higher than 0.018% (v/v) compared to control. Particle size, zeta potential and pH varied between 35 and 133 nm, −26 to −36 mV and 5.67 to 5.38, respectively. Electrolyte leakage was similar for both the control and the treated samples, increasing when essential oils were applied.peer-reviewe

Identification of photocatalytic degradation products of diazinon in TiO2 aqueous suspensions using GC/MS/MS and LC/MS with quadrupole time-of-flight mass spectrometry

AbstractThe photocatalytic degradation of the organophosphorus insecticide diazinon in aqueous suspensions has been studied by using titanium dioxide as a photocatalyst. The degradation of the insecticide was a fast process and included the formation of several intermediates that were identified using GC/ion-trap mass spectrometry with EI or CI in positive and negative ionization mode and HPLC/electrospray-QqTOF mass spectrometry. Since primarily hydroxy derivatives were identified in these aqueous suspensions, the mechanism of degradation was probably based on hydroxyl radical attack. The initial oxidative pathways of the degradation of diazinon involved the substitution of sulfur by oxygen on the PS bond, cleavage of the pyrimidine ester bond, and oxidation of the isopropyl group. Exact mass measurements of the derivatives allowed the elemental formula of the molecules to be determined confidently. Similarities to the metabolic pathways occurring in living organisms were observed

A Low-Overhead Method for Pre-bond Test of Resonant 3-D Clock Distribution Networks

Designing a low power clock network in synchronous circuits is an important task. This requirement is stricter for 3-D circuits due to the increased power densities. Resonant clock networks are considered efficient low power alternatives to con- ventional clock distribution schemes. These networks utilize ad- ditional inductive circuits to reduce power while delivering a full swing clock signal to the sink nodes. Test is another complex task for 3-D ICs, where pre-bond test is a prerequisite. Contactless test has been considered as an alternative for conventional test methods. This paper, consequently, introduces a design method- ology for resonant 3-D clock networks that supports wireless pre- bond testing through the use of inductive links. By employing the inductors comprising the LC tanks of the resonant clock net- works as the receiver circuit for the links, the need for additional circuits and/or interconnect resources during pre-bond test is essentially eliminated. The proposed technique produces low power and pre-bond testable 3-D clock distribution networks. Simulation results indicate 98.5% and 99% decrease in the area overhead and power consumed by the contactless testing method as compared to existing methods

Low-power clock distribution networks for 3-D ICs

Designing a low power clock network in synchronous circuits is an important task. This requirement is stricter for 3-D circuits due to the increased power densities. Resonant clock networks are considered efficient low-power alternatives to conventional clock distribution schemes. These networks utilize additional inductive circuits to reduce the power consumption while delivering a full swing clock signal to the sink nodes. Test is another complex task for 3-D ICs, where pre-bond test is a prerequisite. This paper, consequently, introduces a design methodology for resonant 3-D clock networks that lowers the power of the clock networks while supporting pre-bond test. Several 3-D clock network topologies are explored in a 0.18 μm CMOS technology. Simulation results indicate 43% reduction in the power consumed by the resonant 3-D clock network as compared to a conventional buffered clock network. By properly distributing the inductance within the layers of the 3-D stack, resonance is ensured both in pre-bond test and normal operation. The important aspects of this approach are introduced in this paper

Artificial neural networks as a tool for incorporating microbial stress adaptations in the quantification of microbial inactivation

Quantifying microbial adapted responses due to thermal stresses by an accurate methodology is imperative for assessing the efficacy of a heat process. Two different artificial neural network (ANN) models are constructed for studying the increased induction of the heat resistance of Escherichia coli K12 under a treatment of decreasing heating rates. In the first model structure there are two input vectors, namely, time t and temperature rate dT=dt, whereas in the second case is also added a third one, namely, the microbial load delayed with one time unit Nk¡1. For both models a minimal fully-connected feedforward architecture is used consisting of one hidden neuron and one output neuron. Results as based on the prediction capability of the model structures demonstrate the comparative advantage when an ANN architecture with a delay in its inputs is employed. Incorporation of past events seems to be an essential input for taking into account the observed induced microbial heat resistance.peer-reviewe

COVID-19 one year into the pandemic: from genetics and genomics to therapy, vaccination, and policy

COVID-19 has engulfed the world and it will accompany us all for some time to come. Here, we review the current state at the milestone of 1 year into the pandemic, as declared by the WHO (World Health Organization). We review several aspects of the on-going pandemic, focusing first on two major topics: viral variants and the human genetic susceptibility to disease severity. We then consider recent and exciting new developments in therapeutics, such as monoclonal antibodies, and in prevention strategies, such as vaccines. We also briefly discuss how advances in basic science and in biotechnology, under the threat of a worldwide emergency, have accelerated to an unprecedented degree of the transition from the laboratory to clinical applications. While every day we acquire more and more tools to deal with the on-going pandemic, we are aware that the path will be arduous and it will require all of us being community-minded. In this respect, we lament past delays in timely full investigations, and we call for bypassing local politics in the interest of humankind on all continents