POT1 proteins in green algae and land plants: DNA-binding properties and evidence of co-evolution with telomeric DNA

Telomeric DNA terminates with a single-stranded 3′ G-overhang that in vertebrates and fission yeast is bound by POT1 (Protection Of Telomeres). However, no in vitro telomeric DNA binding is associated with Arabidopsis POT1 paralogs. To further investigate POT1–DNA interaction in plants, we cloned POT1 genes from 11 plant species representing major branches of plant kingdom. Telomeric DNA binding was associated with POT1 proteins from the green alga Ostreococcus lucimarinus and two flowering plants, maize and Asparagus. Site-directed mutagenesis revealed that several residues critical for telomeric DNA recognition in vertebrates are functionally conserved in plant POT1 proteins. However, the plant proteins varied in their minimal DNA-binding sites and nucleotide recognition properties. Green alga POT1 exhibited a strong preference for the canonical plant telomere repeat sequence TTTAGGG with no detectable binding to hexanucleotide telomere repeat TTAGGG found in vertebrates and some plants, including Asparagus. In contrast, POT1 proteins from maize and Asparagus bound TTAGGG repeats with only slightly reduced affinity relative to the TTTAGGG sequence. We conclude that the nucleic acid binding site in plant POT1 proteins is evolving rapidly, and that the recent acquisition of TTAGGG telomere repeats in Asparagus appears to have co-evolved with changes in POT1 DNA sequence recognition

A-infinity structure on simplicial complexes

A discrete (finite-difference) analogue of differential forms is considered, defined on simplicial complexes, including triangulations of continuous manifolds. Various operations are explicitly defined on these forms, including exterior derivative and exterior product. The latter one is non-associative. Instead, as anticipated, it is a part of non-trivial A-infinity structure, involving a chain of poly-linear operations, constrained by nilpotency relation: (d + \wedge + m + ...)^n = 0 with n=2.Comment: final version. 29 page

Non-Radioactive TRF Assay Modifications to Improve Telomeric DNA Detection Efficiency in Plants

© 2016, Springer Science+Business Media New York.The length of telomeric DNA is often considered a cellular biomarker of aging and general health status. Several telomere length measuring assays have been developed, of which the most common is the telomere restriction fragment (TRF) analysis, which typically involves the use of radioactively labeled oligonucleotide probes. While highly effective, this method potentially poses substantial health concerns and generates radioactive waste. Digoxigenin (DIG) alternatives to radioactive probes have been developed and used successfully in a number of assays. Here, we optimize the DIG protocol to measure telomere length in the model plant Arabidopsis thaliana and present evidence that this approach can be used successfully to efficiently and accurately measure telomere length in plants. Specifically, hybridization temperature of 42 °C instead of the typical 55 °C appears to generate stronger signals. In addition, DIG incorporation at 5′-end instead of 3′-end of the labeled oligonucleotide greatly enhances signal. We conclude that non-radioactive TRF assays can be as efficient as radioactive methods in detecting and measuring telomere length in plants, making this assay suitable for medical and research laboratories unable to utilize radioactivity due to hazardous waste disposal and safety concerns

Histidine Acid Phytases of Microbial Origin

© 2018, Pleiades Publishing, Ltd. Abstract—: This review is focused on analysis of the biological diversity of phytase-producing microorganisms capable of degrading phytate to inorganic phosphate. General approaches to microbial phytase classification are discussed, with a particular emphasis on histidine acid phytases (HAPs), which catalyze specific cleaving of myo-inositol hexakisphosphate. The effect of glycosylation and various effectors on enzyme thermostability and activity of phytases are described. The data on the biosynthesis of histidine acid phytases, their substrate specificity, and on the mechanism of myo-inositol hexakisphosphate hydrolysis are considered. A conclusion is made concerning the biotechnological potential of this group of microbial enzymes

An improved gene expression system to generate transgenic arabidopsis thaliana plants harboring a Bacillus ginsengihumi phytase gene

We constructed a new vector system for heterologous gene expression in Arabidopsis thaliana. The construct contains a codon-optimized sequence encoding Bacillus ginsengihumi phytase behind an inducible plant-specific promoter for expression in root epithelial cells. The new vector introduced into the plant A. thaliana by Agrobacterium mediated transformation. We obtained several generations of transgenic A. thaliana plants with integrated Bacillus ginsengihumi phytase gene, as well as with an empty vector as a negative control. We tested several transgenic plants harboring the phyCg construct under the control of phosphate-starvation inducible Pht1;2 promoter and show that the phyCg gene is expressed at the mRNA level. Further characterization of these lines of plants will help us to design an improved transgenic strategy for the development of a root-specific heterologous system for the expression of bacterial phytases in plants

ПРОБЛЕМА ВОЗРАСТНОГО ЦИФРОВОГО РАЗРЫВА СОВРЕМЕННОСТИ

There are currently three broad trends in the world: the aging of our population, the continuing urbanization of human societies and the growing dependence on information and communication technologies (ICT). Demographic changes leading to an aging population are occurring simultaneously with rapid technological changes. This article discusses the problems faced by older people aged 65 and over.В настоящее время в мире существуют три широкие тенденции: старение нашего населения, продолжающаяся урбанизация человеческих обществ и растущая зависимость от информационно-коммуникационных технологий (ИКТ). Демографические изменения, ведущие к старению населения, происходят одновременно с быстрыми технологическими изменениями. В данной статье рассматриваются проблемы, с которыми сталкиваются пожилые люди в возрасте от 65 лет

Structural characteristics and catalytic mechanism of Bacillus β-propeller phytases

© 2016, Pleiades Publishing, Ltd.ß-Propeller phytases of Bacillus are unique highly conservative and highly specific enzymes capable of cleaving insoluble phytate compounds. In this review, we analyzed data on the properties of these enzymes, their differences from other phytases, and their unique spatial structures and substrate specificities. We considered influences of different factors on the catalytic activity and thermostability of these enzymes. There are few data on the hydrolysis mechanism of these enzymes, which makes it difficult to analyze their mechanism of action and their final products. We analyzed the available data on hydrolysis by ß-propeller phytases of calcium complexes with myo-inositol hexakisphosphate

Crystal growth and preliminary X-ray study of glutamic acid specific serine protease from Bacillus intermedius

The glutamic acid specific protease (glutamyl-endopeptidase) from Bacillus intermedius, strain 3-19, was isolated and purified using ion exchange chromatography on CM-cellulose and Mono-S FPLC column. The conditions for crystallization of the enzyme have been discussed. The crystals of enzyme were grown using hanging-drop vapor-diffusion technique. Crystals belong to the space group C2 with unit cell parameters of a = 61.62 Å, b = 55.84 Å, c = 60.40 Å, β = 117.6° X-ray diffraction data to 1.68 Å resolution were collected using synchrotron radiation (EMBL, Hamburg) and an imaging plate scanner. © 1999 Elsevier Science B.V. All rights reserved