Expression, purification, and characterization of the yeast KEX1 gene product, a polypeptide precursor processing carboxypeptidase.

The Saccharomyces cerevisiae KEX1 gene encodes a protease with carboxypeptidase B-like activity involved in K1 and K2 killer toxins and alpha-factor (mating pheromone) precursors processing. The gene has been expressed using the baculovirus/insect cell system, and the KEX1 encoded protein (Kex1p) was purified to apparent homogeneity from detergent-solubilized membrane preparations of insect cells infected with the recombinant virus. The specific activity of the enzyme was enriched 126-fold as compared with the cell lysate, with a recovery of 29%. The NH2-terminal sequence of the purified active enzyme was identical to the predicted sequence after the removal of the signal peptide. This provides evidence that Kex1p, at least in insect cells, is not made as a proenzyme. The optimum pH for activity was 6.0, and the apparent pI value of the protein was below pH 3.0. The enzyme cleaves arginine or lysine from the COOH terminus of synthetic peptides: benzoyl-Phe-Ala-Arg (Km = 284 microM), furylacryloyl (fa)-Ala-Arg (Km = 516 microM), and fa-Ala-Lys (Km = 962 microM). The kinetic data obtained reveals that Kex1p preferentially cleaves the COOH-terminal arginine of peptides over the COOH-terminal lysine. Insect-derived Kex1p processes alpha-factor-Lys-Arg, its known natural substrate, to mature active alpha-factor, and this maturation event takes place in a sequential manner. Furthermore, the enzyme expresses very high affinity for the 15-amino acid-long peptide, alpha-factor-Lys-Arg (Ki = 22 microM), and somewhat lower affinity for the heptapeptides [Leu]enkephalin-Arg-Arg,-Arg-Lys, and [Met]enkephalin-Lys-Lys (Ki = 45, 57, and 81 microM, respectively). The data demonstrate that processing at the COOH terminus of the peptides tested stops after the cleavage of the Arg and/or Lys residues. The specificity of the enzyme for COOH-terminal basic amino acid residues of the peptides used in this study and its high affinity for alpha-factor-Lys-Arg confirms the role that Kex1p plays in polypeptide precursor processing in yeast

A ZnO nanorod based 64° YX LiNbO3 surface acoustic wave CO sensor

Zinc oxide (ZnO) nanorod based surface acoustic wave (SAW) gas sensor has been developed. ZnO nanorods were deposited onto a layered ZnO/64deg YX LiNbO<sub>3</sub> substrate using a liquid solution method. Micro-characterization results reveal that the diameter and area density of ZnO nanorods are around 100 nm and 107 cm<sup>-2</sup>, respectively. The sensor was exposed to different concentrations of CO in synthetic air. The sensor response at operating temperatures between 200°C and 300°C was examined. The study showed that the sensor responded with highest frequency shift at 265°C. At this temperature, stable base-line and fast response and recovery were observed. The developed sensor is promising for industrial applications

Nanostructured molybdenum oxide gas sensors

In this paper, we present a surface acoustic wave (SAW) gas sensor based on nano-structured molybdenum oxide (MoOx) thin film. The film was deposited onto a 36° YX LiTaO3 SAW transducer, with an operating frequency of approximately 103 MHz, by thermal evaporation. The nanostructured MoOx film consists of connected nanorods with diameters of less than 100 nm. We compared devices with MoOx deposited by RF sputtering and thermal evaporation and found those with evaporated films have response that are an order of magnitude larger

MAST CELLS AS BIOMARKERS OF INFLAMM-AGEING

Most mechanisms of ageing are believed to be more or less associated with inflammation. With age, a unique form of chronic inflammation develops which is termed as “inflamm-ageing”. The mechanisms of this process are still not fully clear due to the lack of reliable assessment criteria. Immune system is among those involved in accelerating age-related changes in the body. It also directly participates in the process of inflammation. In its pathogenesis, the reaction of mast cells may be of great importance. The role of mast cells in tissue remodeling deserves special attention, since the latter event is among the main features associated with ageing. Hence, the “inflamm-ageing” is considered a sufficient indicator of ageing, and the mast cells could provide biomarkers of this process. In order to test the proposed hypothesis, the present study was conducted to determine age-related morpho-functional changes in mast cell populations in various organs in rats. Some morpho-functional parameters of mast cells (number, synthetic and functional activity, degree of maturation) in different animal organs were evaluated in male Wistar rats of different ages (4 months and 2 years). We have found the age-dependent changes upon examination of thymus, adrenal glands, and skin, i.e., a decrease in the number of mast cells and their synthetic capacity, along with significantly increased functional activity. In the stomach, small and large intestines, at the constant number of mast cells, we revealed a decrease in their synthetic ability, and increased functional activity. These changes were accompanied by enlargement of blood vessels in the studied organs. Liver is the only organ which did not exhibit any changes in mast cell populations with age. The detected changes in mast cell populations may play an important role in formation of “inflamm-ageing” events, which accompany the ageing processes, because these cells are an integral component of inflammatory response. The progression of “inflamm-ageing” leads to accumulation of cytokines and pro-inflammatory mediators in tissues, which, in turn, activate the mast cells. At the same time, increased degranulation of mastocytes may promote the process of “inflamm-ageing”. The oberved mutual influence of mast cells and “inflamm-ageing” makes it possible to consider mastocytes as potential candidates for searching the biomarkers in “inflamm-ageing”. © 2022, RSI

Triangular Textures for Quark Mass Matrices

The hierarchical quark masses and small mixing angles are shown to lead to a simple triangular form for the U- and D-type quark mass matrices. In the basis where one of the matrices is diagonal, each matrix element of the other is, to a good approximation, the product of a quark mass and a CKM matrix element. The physical content of a general mass matrix can be easily deciphered in its triangular form. This parameterization could serve as a useful starting point for model building. Examples of mass textures are analyzed using this method.Comment: 10 pages, no figure

Water Absorption Enhancement Of Sodium Poly Acrylate And Poly(2-Acrylamido-2-Methylpropane Sulphonic Acid) Based Hydrogel Mixtures

Introduction: Hydrogels are hydrophilic polymers which are cross-linked to form three-dimensional structures, which can absorb, swell and retain huge amounts of water or aqueous fluids. Objective: This paper reports the preparation and characterization of Poly (2-Acrylamido-2-Methylpropane Sulphonic Acid) (PAMPS) hydrogel with different crosslinking intensities. Methodology: 2-Acrylamido-2-methylpropane sulfonic acid (AMPS) monomer was purchased from Alfa Aesar Company as reagent grade. It was used as received (\u3e98% purity) without any further purification. PAMPS hydrogel was prepared by free radical crosslinking solution polymerization of AMPS in water at room temperature under a nitrogen blanket in cylindrical glass tubes. The characteristics of the obtained PAMPS hydrogel were compared with those of commercial sodium polyacrylates hydrogel. Results: It was found that decreasing the crosslinker weight improved the absorbance capacity but to a limit. The suggested reasons were discussed. The mixture showed higher absorbance rate than PAMPS, and bigger absorbance capacity than sodium polyacrylates. Conclusion: This paper investigates the effect of crosslinker ratio on the swelling capacity of PAMPS. It was found that as the crosslinking ratio decreases, the porosity of the hydrogel increases, thus improving the swelling capacity

EFFECT OF SOME POST-HARVEST TREATMENTS ON CUT LEAVES OF CHAMAEDOREA ELEGANS

This study was carried out at the Post-harvest Lab. of Ornamental Plants and Landscape Gardening Res. Dept., Hort. Res. Inst., Giza, Egypt during the two seasons of 2014/2015 and 2015/2016. The aim of this study is to investigate the effect of GA3, BA, 8-HQC, CA and Sug. as preservative solution on improving the quality of the leaves, delaying leaf wilting and leaf yellowing and extending the shelf life period of cut leaves of Chamaedorea elegans. The results showed that, the treatment of the solution containing T14: GA3 at 50 ppm + BA at 20 ppm + 8-HQC at 300 ppm + CA at 300 ppm + Sug. at 2%, followed by the solution containing the T13: GA3 at 50 ppm + BA at 20 ppm + CA at 300 ppm +  Sug. at 2% significantly increased the water uptake, water balance, general appearance, vase life, concentration of chlorophyll a, b, carotenoids and total carbohydrates. It also reduced the amount of water loss in all days compared to other treatments. It can be recommended holding cut foliage of Chamaedorea elegans in solution containing GA3 at 50 ppm + BA at 20 ppm + 8-HQC at 300 ppm + CA at 300 ppm + Sug. at 2% followed by the solution containing GA3 at 50 ppm + BA at 20 ppm + CA at 300 ppm + Sug. at 2% to improve cut leaves quality and longer vase life was reached 84 days

Mass Hierarchies and the Seesaw Neutrino Mixing

We give a general analysis of neutrino mixing in the seesaw mechanism with three flavors. Assuming that the Dirac and u-quark mass matrices are similar, we establish simple relations between the neutrino parameters and individual Majorana masses. They are shown to depend rather strongly on the physical neutrino mixing angles. We calculate explicitly the implied Majorana mass hierarchies for parameter sets corresponding to different solutions to the solar neutrino problem.Comment: 11 pages, no figures, replaced with final version. Minor corrections and one typo corrected. Added one referenc

EFFECT OF SOME POST-HARVEST TREATMENTS ON UNROOTED CUTTING OF DRACAENA MARGINATA

This study was carried out at the Post-harvest Lab. of Ornamental Plants and Landscape Gardening Res. Dept., Hort. Res. Inst., Giza, Egypt during the two seasons of 2014/2015 and 2015/2016. The aim of this study is to investigate the effect of GA3, BA, 8-HQC, CA and Sug. as the preservative solution to improve the quality of the unrooted cutting, delaying leaf wilting, leaf yellowing and extending the shelf life period of unrooted cutting of Dracaena marginata. The results revealed that, the treatment of the solution containing the GA3 at 50 ppm + BA at 20 ppm + 8-HQC at 300 ppm + CA at 300 ppm + Sug. at 2%, followed by the solution containing GA3 at 50 ppm + BA at 20 ppm + CA at 300 ppm + Sug. at 2% significantly increased the water uptake, water balance, general appearance, vase life, chlorophyll a, b, carotenoids and total carbohydrates. It also reduced the amount of water loss in all days compared to other treatments. It can be recommended that holding unrooted cutting of Dracaena marginata in a solution containing GA3 at 50 ppm + BA at 20 ppm + 8-HQC at 300 ppm + CA at 300 ppm + Sug. at 2%, followed by the solution containing GA3 at 50 ppm + BA at 20 ppm + CA at 300 ppm + Sug. at 2% to improve quality and giving longer vase life was reached 50 days