Biology subjects

Novikov, I. A.

Publications and source records attributed to Novikov, I. A..

3 recordsLinked to original sources

bioRxiv2025

Mechanical properties of adherent cell sheets analyzed by deflection of supporting membrane

Multicellular structures, including cell sheets, are actively used as model systems to study intercellular interactions and can be applied in different areas of regenerative medicine. In this paper, we present a novel approach for measuring mechanical properties of cell sheets based on a simple experimental setup and numerical simulations. The advantage of the present approach is the relative ease of the sample preparation, while previous systems for the tensile tests required specialized and sensitive equipment. With the developed approach, the cell sheet on a polymer membrane is mounted in the holder on one side, and then deflection of the free end of the membrane is measured. The deflection of this cantilever-like construction depends on the elastic modulus of the membrane (which is known) and cell sheet, and also from the traction force generated by the cell sheet. By involving an experimental step with relaxing the traction force and by conducting finite element simulations, both traction force and elastic properties of the cell sheet can be estimated. We performed such measurements on cell sheets from keratocytes from corneal explants and confirmed that the developed approach is applicable for measurement of both traction force and elastic modulus of cell sheets.

biophysics↗

bioRxiv2024

rRNA-specific antisense DNA and dsDNA trigger rRNA biogenesis and cause potent insecticidal effect on insect pest Coccus hesperidum L.

Invented in 2008, contact unmodified antisense DNA biotechnology (CUADb) is built on the use of short antisense DNA oligonucleotides (oligos) for insect pest control. Being a novel class of insecticides, oligonucleotide insecticides target pest rRNAs and/or pre-rRNAs and recently showed high insecticidal potential against sap-feeding insect pests, main vectors of plant DNA viruses and one of the most economically-damaging groups of herbivorous insects. In order to use all possible opportunities of CUADb, in this article insecticidal potential of short 11-mer antisense DNA oligos was investigated for Coccus hesperidum control in comparison with long 56-mer single-stranded and double-stranded DNA sequences and lower efficiency of the latter was found. At the end of the experiment, on the 9th day, the highest mortality rate among antisense oligos was reached for Coccus-11 group (97.66 {+/-} 4.04 %), while for long sequences the highest mortality rate was obtained for double-stranded DNA fragment in dsCoccus-56 group (77.09 {+/-} 6.24 %). Also in this article architecture of DNA containment (DNAc) mechanism is described representing interesting and important for insect cell life interplay between rRNAs and different types of DNA oligos. During DNAc, Coccus-11 caused increased ribosome biogenesis and ATP production through metabolic switch in energy synthesis from carbohydrates to lipids but eventually caused kinase disaster through downregulation of most kinases due to insufficient level of ATP produced. In the course of DNAc, hypercompensation of target rRNA is triggered by all highly and all somewhat complementary DNA oligos but more pronounced later degradation of target rRNA and significant insect pest mortality is seen only in the case of perfect complementarity of oligonucleotides to target rRNA. For both short and long oligonucleotide insecticides substantial decrease in rRNA concentration after rRNA hypercompensation in average by 3.75-4.25 fold, is explained by the work of DNA-guided rRNase, like RNase H1. We detected significant upregulation of RNase H1 after application of Coccus-11 in this study. On the contrary, for short and long random DNA oligos concentration of rRNA decreased in average by 2-3 fold after rRNA hypercompensation due to normal half-life of rRNAs in insect cells provided by ribonucleases. Fundamentally important, obtained results show completely new principle of regulation of rRNA expression in the cell via complementary interaction between rRNAs and unmodified antisense sequences of exogenous DNA. Practically important, this minimalist approach of using short antisense DNA dissolved in water is potent and eco-friendly innovation against sternorrhynchans and other pests, and reveals entirely new dimension to plant protection - DNA-programmable insect pest control.

molecular biology↗

bioRxiv2024

Potent and selective 'genetic zipper' method for plant protection: innovative DNA psyllidicides against Trioza alacris Flor based on short unmodified antisense oligonucleotides targeting rRNA of the pest

Chemical insecticides increased the chemical burden on natural ecosystems posing environmental health risk factor. The urgent need for a more sustainable and ecological approach has produced many innovative ideas, including eco-friendly genetic zipper method (or CUAD platform) based on contact oligonucleotide insecticides. Oligonucleotide insecticides have enjoyed success recently on many sternorrhynchans showing highly adaptable structure for distinct insect pest species and selective mode of action. In this article, we describe the efficiency of the oligonucleotide insecticides (briefly, olinscides or DNA insecticides) Alacris-11 and Laura-11, as well as their combined use in mixture (1:1), designed for control of bay sucker (Trioza alacris Flor), an important psyllid pest of noble laurel (Laurus nobilis L.). These olinscides are based on short unmodified antisense DNA oligonucleotides that target ITS2 between 5.8S rRNA and 28S rRNA in pre-rRNA (Laura-11) and 28S rRNA region in mature 28S rRNA and pre-rRNA (Alacris-11). The maximum pest mortality, observed on 14th day of the experiment, comprised 95.01 {+/-} 4.42 % for Alacris-11, 97.16 {+/-} 2.48 % for Laura-11, and 98.72 {+/-} 1.14 % for their mixture (1:1). The control oligonucleotide CTGA-11 did not cause any significant mortality (9.38 {+/-} 0.57 %), emphasizing selectivity in the action of oligonucleotide insecticides. The results show potent and specific nature of oligonucleotide insecticides for pest control and opens up new frontiers in control of economically important psyllids in agriculture and forestry, including Asian citrus psyllid (Diaphorina citri Kuwayama) and many others. Scientists can easily adopt genetic zipper method for plethora of insect pests because DNA is a programmable molecule and provides game-changing characteristics for plant projection.

molecular biology↗