A comprehensive overview of miRNA targeting drought stress resistance in plants

MicroRNAs (miRNAs) are essential nonprotein-coding genes. In a range of organisms, miRNAs has been reported to play an essential role in regulating gene expressions at post-transcriptional level. They participate in most of the stress responsive processes in plants. Drought is an ultimate abiotic stress that affects the crop production. Therefore understanding drought stress responses are essential to improve the production of agricultural crops. Throughout evolution, plants have developed their own defense systems to cope with the adversities of environmental stresses. Among defensive mechanisms include the regulations of gene expression by miRNAs. Drought stress regulates the expression of some of the functionally conserved miRNAs in different plants. The given properties of miRNAs provide an insight to genetic alterations and enhancing drought resistance in cereal crops. The current review gives a summary to regulatory mechanisms in plants as well as miRNAs response to drought stresses in cereal crops. Some possible approaches and guidelines for the exploitation of drought stress miRNA responses to improve cereal crops are also described.

The fifth Japanese meeting on biological function and evolution through interactions between hosts and transposable elements

The fifth Japanese meeting on host–transposon interactions, titled “Biological Function and Evolution through Interactions between Hosts and Transposable Elements (TEs),” was held online on August 26–27, 2021. The meeting was supported by National Institute of Genetics and aimed to bring together researchers studying the diverse roles of TEs in genome function and evolution, as well as host defense systems against TE mobility by chromatin and RNA modifications and protein-protein interactions. Here, we present the highlights of the talks.

Microbial defenses against mobile genetic elements and viruses: Who defends whom from what?

Prokaryotes have numerous mobile genetic elements (MGEs) that mediate horizontal gene transfer (HGT) between cells. These elements can be costly, even deadly, and cells use numerous defense systems to filter, control, or inactivate them. Recent studies have shown that prophages, conjugative elements, their parasites (phage satellites and mobilizable elements), and other poorly described MGEs encode defense systems homologous to those of bacteria. These constitute a significant fraction of the repertoire of cellular defense genes. As components of MGEs, these defense systems have presumably evolved to provide them, not the cell, adaptive functions. While the interests of the host and MGEs are aligned when they face a common threat such as an infection by a virulent phage, defensive functions carried by MGEs might also play more selfish roles to fend off other antagonistic MGEs or to ensure their maintenance in the cell. MGEs are eventually lost from the surviving host genomes by mutational processes and their defense systems can be co-opted when they provide an advantage to the cell. The abundance of defense systems in MGEs thus sheds new light on the role, effect, and fate of the so-called “cellular defense systems,” whereby they are not only merely microbial defensive weapons in a 2-partner arms race, but also tools of intragenomic conflict between multiple genetic elements with divergent interests that shape cell fate and gene flow at the population level.

Towards a better understanding of antimicrobial resistance dissemination: what can be learnt from studying model conjugative plasmids?

Bacteria can evolve rapidly by acquiring new traits such as virulence, metabolic properties, and most importantly, antimicrobial resistance, through horizontal gene transfer (HGT). Multidrug resistance in bacteria, especially in Gram-negative organisms, has become a global public health threat often through the spread of mobile genetic elements. Conjugation represents a major form of HGT and involves the transfer of DNA from a donor bacterium to a recipient by direct contact. Conjugative plasmids, a major vehicle for the dissemination of antimicrobial resistance, are selfish elements capable of mediating their own transmission through conjugation. To spread to and survive in a new bacterial host, conjugative plasmids have evolved mechanisms to circumvent both host defense systems and compete with co-resident plasmids. Such mechanisms have mostly been studied in model plasmids such as the F plasmid, rather than in conjugative plasmids that confer antimicrobial resistance (AMR) in important human pathogens. A better understanding of these mechanisms is crucial for predicting the flow of antimicrobial resistance-conferring conjugative plasmids among bacterial populations and guiding the rational design of strategies to halt the spread of antimicrobial resistance. Here, we review mechanisms employed by conjugative plasmids that promote their transmission and establishment in Gram-negative bacteria, by following the life cycle of conjugative plasmids.

Substance Use Disorder and COVID-19; Forensic Medicine and Pharmacology Perspectives: A Concise Narrative Review

Many investigations have confirmed the link between a substance use disorder (SUD) and the COVID-19 pandemic's increased risk of infection and consequences. This narrative review aims to understand these issues from a pharmacological standpoint, as well as the pandemic's impact on forensic medicine. Research and review articles included in this review were selected through an extensive search of databases such as PubMed and the use of appropriate keywords e.g. “substance use disorder” and “COVID-19”. Due to a weakened immune system and degeneration of the respiratory system's defense systems, SUDs have been shown to increase the risk of COVID-19 infection. Furthermore, some substances raise pro-inflammatory mediators, exposing the body to a cytokine storm. SUD frequently causes secondary comorbidities, such as the liver, lung and cardiovascular disease, complicating the treatment of COVID-19 infections. Some misused substances can compromise the treatment's effectiveness or safety. This study also looked at the effects of the pandemic on forensic medicine. It underlines the importance of developing safe forensic examination procedures and methodologies during pandemics. The use of narcotic substances was documented as one of the reasons for the increase in the frequency of COVID-19 and the severity of its repercussions.

Differential Fatty Acids and Stress Biomarkers Responses in Native (Carcinus Aestuarii) and Invasive (Portunus Segnis) Crabs Exposed to Environmental Pollution

The present work aims to determine and compare the tolerance to different stress environmental conditions in two crabs’ species the native Carcinus aestuarii and the invasive Portunus segnis. In this study, C.aestuarii appeared more intolerant to environmental stressor as shown by the important changes occurred on the proximate, fatty acids and their essential compounds comparing to P.segnis. Our results revealed accumulation of metallic trace elements, macromolecular damages and antioxidant defense systems perturbations mostly in C.aesuarii gills and muscles than P.segnis, thus highlighting the importance of a multi-markers approach to assess the urban pollution in coastal ecosystems. According to this study, fatty acid profiles and oxidative stress biomarker examination of both crabs indicate that the different environmental stresses significantly influence the tolerance of C.aestuarii compared to the invasive P.segnis which may provide physiological advantages for the achievement of their invasion in novel ecosystems.

An Interplay between Viruses and Bacteria Associated with the White Sea Sponges Revealed by Metagenomics

Sponges are remarkable holobionts harboring extremely diverse microbial and viral communities. However, the interactions between the components within holobionts and between a holobiont and environment are largely unknown, especially for polar organisms. To investigate possible interactions within and between sponge-associated communities, we probed the microbiomes and viromes of cold-water sympatric sponges Isodictya palmata (n = 2), Halichondria panicea (n = 3), and Halichondria sitiens (n = 3) by 16S and shotgun metagenomics. We showed that the bacterial and viral communities associated with these White Sea sponges are species-specific and different from the surrounding water. Extensive mining of bacterial antiphage defense systems in the metagenomes revealed a variety of defense mechanisms. The abundance of defense systems was comparable in the metagenomes of the sponges and the surrounding water, thus distinguishing the White Sea sponges from those inhabiting the tropical seas. We developed a network-based approach for the combined analysis of CRISPR-spacers and protospacers. Using this approach, we showed that the virus–host interactions within the sponge-associated community are typically more abundant (three out of four interactions studied) than the inter-community interactions. Additionally, we detected the occurrence of viral exchanges between the communities. Our work provides the first insight into the metagenomics of the three cold-water sponge species from the White Sea and paves the way for a comprehensive analysis of the interactions between microbial communities and associated viruses.

Detection and Tracking of UAV Targets Using Deep Learning

In recent years, the use of Flying drones and modern Unmanned aerial vehicles (UAVs) with the latest techniques and capabilities for both civilian and military applications growing sustainably on a large scope, Drones could autonomously fly in several environments and locations and could perform various missions, providing a system for UAV detection and tracking represent crucial importance. This paper discusses Designing Detection and Tracking method as a part of Aero-vehicle Defense System (ADS) for UAVs using Deep learning algorithms. The small Radar cross-section (RCS) foot-print makes a problem for Traditional methods and Aero-vehicle Defense systems to distinguish between birds, stealth fighters, and UAVs incomparable of size and RCS characteristics, the detection is a challenge in low RCS targets because the chance of detection is incredibly less moreover, in the existence of interference and clutter which reduce the performance of detection process rapidly.

Multiple phage resistance systems inhibit infection via SIR2-dependent NAD+ depletion

Defense-associated sirtuins (DSR) comprise a family of proteins that defend bacteria from phage infection via an unknown mechanism. These proteins are common in bacteria and harbor an N-terminal sirtuin (SIR2) domain. In this study we report that DSR proteins degrade nicotinamide adenine dinucleotide (NAD+) during infection, depleting the cell of this essential molecule and aborting phage propagation. Our data show that one of these proteins, DSR2, directly identifies phage tail tube proteins and then becomes an active NADase in Bacillus subtilis. Using a phage mating methodology that promotes genetic exchange between pairs of DSR2-sensitive and DSR2-resistant phages, we further show that some phages express anti-DSR2 proteins that bind and repress DSR2. Finally, we demonstrate that the SIR2 domain serves as an effector NADase in a diverse set of phage defense systems outside the DSR family. Our results establish the general role of SIR2 domains in bacterial immunity against phages.