scholarly journals Paving the Way to Unveil the Diversity and Evolution of Phage Genomes

Viruses ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 905
Author(s):  
Alejandro Reyes ◽  
Martha J. Vives
Keyword(s):  
Molecular Evolution ◽  
Host Range ◽  
Molecular Mechanisms ◽  
Bacterial Resistance ◽  
Viral Pathogenesis ◽  
Resistance Mechanisms ◽  
Molecular Tools ◽  
Special Issue ◽  
Bacterial Host ◽  
Host Interactions

Phage biology has been developing for the last hundred years, and the potential of phages as tools and treatments has been known since their early discovery. However, the lack of knowledge of the molecular mechanisms coded in phage genomes hindered the development of the field. With current molecular methods, the last decade has been a resurgence of the field. The Special Issue on “Diversity and Evolution of Phage Genomes” is a great example with its 17 manuscripts published. It covers some of the latest methods to sample and characterize environmental and host associated viromes, considering experimental biases and computational developments. Furthermore, the use of molecular tools coupled with traditional methods has allowed to isolate and characterize viruses from different hosts and environments with such diversity that even a new viral class is being proposed. The viruses described cover all different phage families and lifestyles. However, is not only about diversity; the molecular evolution is studied in a set of manuscripts looking at phage-host interactions and their capacity to uncover the frequency and type of mutations behind the bacterial resistance mechanisms and viral pathogenesis, and such methods are opening new ways into identifying potential receptors and characterizing the bacterial host range.

scholarly journals Molecular Mechanisms of Bacterial Resistance to Metal and Metal Oxide Nanoparticles

2019 ◽  
Vol 20 (11) ◽  
pp. 2808 ◽  
Author(s):  
Nereyda Niño-Martínez ◽  
Marco Felipe Salas Orozco ◽  
Gabriel-Alejandro Martínez-Castañón ◽  
Fernando Torres Méndez ◽  
Facundo Ruiz
Keyword(s):  
Metal Oxide ◽  
Molecular Mechanisms ◽  
Bacterial Resistance ◽  
Bacterial Species ◽  
Metal Oxide Nanoparticles ◽  
Multidrug Resistant ◽  
Resistance Mechanisms ◽  
Resistant Bacteria ◽  
Oxide Nanoparticles ◽  
Multidrug Resistant Bacteria

The increase in bacterial resistance to one or several antibiotics has become a global health problem. Recently, nanomaterials have become a tool against multidrug-resistant bacteria. The metal and metal oxide nanoparticles are one of the most studied nanomaterials against multidrug-resistant bacteria. Several in vitro studies report that metal nanoparticles have antimicrobial properties against a broad spectrum of bacterial species. However, until recently, the bacterial resistance mechanisms to the bactericidal action of the nanoparticles had not been investigated. Some of the recently reported resistance mechanisms include electrostatic repulsion, ion efflux pumps, expression of extracellular matrices, and the adaptation of biofilms and mutations. The objective of this review is to summarize the recent findings regarding the mechanisms used by bacteria to counteract the antimicrobial effects of nanoparticles.

scholarly journals Announcement of the 2019 BLAST Conference: “BLAST XV: 15th International Conference on Bacterial Locomotion and Signal Transduction”

mSystems ◽  
2018 ◽  
Vol 3 (5) ◽  
Author(s):  
Christine Josenhans ◽  
Robert B. Bourret ◽  
Karen Ottemann ◽  
Rasika Harshey ◽  
Ariane Briegel ◽  
...  
Keyword(s):  
Signal Transduction ◽  
New Orleans ◽  
Structural Biology ◽  
Cell Biology ◽  
Molecular Mechanisms ◽  
Early Career ◽  
Bacterial Host ◽  
Signaling Systems ◽  
Host Interactions ◽  
Bacterial Signal Transduction

ABSTRACT An exciting conference showcasing cutting edge research in bacterial signal transduction, chemotaxis, and motility will be held in January 2019. This conference, called Bacterial Locomotion and Signal Transduction (BLAST), will be held in New Orleans, LA, USA, under the auspices of chair Birgit Scharf. The conference has been held biennially since 1991 and highlights presentations from early-career scientists. The majority of talks are from submitted abstracts, interspersed by presentations of internationally renowned scientists. Six awards will be presented specifically to young researchers. The main goal is to bring together researchers at the junior and experienced levels from a wide variety of research disciplines. Topics showcased include structural biology, computational biology, modeling, and cell biology covering molecular mechanisms of bacterial movement, systems biology, evolution of signaling systems, computational modeling of nanomachine function, and bacterial-host interactions. The combination of broad-scope and in-depth science will continue to inspire breakthrough technical and scientific advances.

scholarly journals RNase R, a new virulence determinant of Streptococcus pneumoniae

2021 ◽  
Author(s):  
Cátia Bárria ◽  
Dalila Mil-Homens ◽  
Arsénio M. Fialho ◽  
Cecília Maria Arraiano ◽  
Susana Domingues
Keyword(s):  
Molecular Mechanisms ◽  
Bacterial Resistance ◽  
Galleria Mellonella ◽  
Bacterial Load ◽  
Infection Model ◽  
Virulence Determinants ◽  
Pneumococcal Infections ◽  
Rnase R ◽  
Host Interactions ◽  
Eclipse Phase

ABSTRACTPneumococcal infections have increasingly high mortality rates despite the availability of vaccines and antibiotics. The increase of bacterial resistance to antibiotics urges the discovery of new alternative therapeutics. Therefore, the identification of new virulence determinants, and the understanding of the molecular mechanisms behind pathogenesis and pneumococcal-host interactions has become of paramount importance in the search of new targets for drug development. The exoribonuclease RNase R has been involved in virulence in a growing number of pathogens. In this work, we have used Galleria mellonella as an infection model to demonstrate that the presence of ribonuclease R increases the pneumococcus virulence. Although the absence of RNase R does not affect exponential growth, the ability of the RNase R deleted strain to replicate in the hemolymph is compromised. Larvae infected with the RNase R mutant strain show an increased expression level of antimicrobial peptides, and have a lower bacterial load in the haemolymph in the later stages of infection, leading to a higher survival rate. Interestingly RNase R carrying pneumococci suffer a sudden drop in bacterial numbers immediately after infection, resembling the eclipse phase observed after intravenous inoculation in mice. Together our results suggest that RNase R might be involved in the ability of pneumococci to evade the host immune response, probably by interfering with internalisation and/or replication inside the larval hemocytes.

Modulation of Drug Resistance by Limonene: Inhibition of Efflux Pumps in Staphylococcus aureus Strains RN-4220 and IS-58

2021 ◽  
Vol 21 ◽  
Author(s):  
Ana Carolina Justino de Araújo ◽  
Priscilla Ramos Freitas ◽  
Cristina Rodrigues dos Santos Barbosa ◽  
Débora Feitosa Muniz ◽  
Jaime Jaime Ribeiro-Filho ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Ethidium Bromide ◽  
Molecular Mechanisms ◽  
Bacterial Resistance ◽  
Efflux Pump ◽  
Antibacterial Properties ◽  
Resistance Mechanisms ◽  
Pathogenic Potential ◽  
Microdilution Method ◽  
Broth Microdilution Method

Aims: This study aimed to investigate the potential of limonene as an efflux pump (EP) inhibitor in Staphylococcus aureus strains RN-4220 and IS-58, which carry EPs for erythromycin (MrsA) and tetracycline (TetK), respectively. Background: The evolution of bacterial resistance mechanisms over time has impaired the action of most classes of antibiotics. Staphylococcus aureus is a notable bacterium, with high pathogenic potential and demonstrated resistance to conventional antibiotics. Considering the importance of discovering novel compounds to combat antibiotic resistance, our group previously demonstrated the antibacterial properties of limonene, a compound present in the essential oils of several plant species. Objective: This study aimed to investigate the potential of limonene as an efflux pump (EP) inhibitor in Staphylococcus aureus strains RN-4220 and IS-58, which carry EPs for erythromycin (MrsA) and tetracycline (TetK), respectively. Method: The minimum inhibitory concentrations (MIC) of limonene and other efflux pump inhibitors were determined through the broth microdilution method. A reduction in the MIC of ethidium bromide was used as a parameter of EP inhibition. Result: While limonene was not shown to exhibit direct antibacterial effects against EP-carrying strains, in association with ethidium bromide and antibiotics, this compound demonstrated enhanced antibacterial activity, indicating the inhibition of the MrsA and TetK pumps. Conclusion: In conclusion, this pioneering study demonstrated the effectiveness of limonene as an EP inhibitor in S. aureus strains RN-4220 and IS-58. Nevertheless, further studies are required to characterize the molecular mechanisms associated with limonene-mediated EP inhibition.

Anticancer Agents Based on Vulnerable Components in a Signalling Pathway

2020 ◽  
Vol 20 (10) ◽  
pp. 886-907 ◽  
Author(s):  
Ankur Vaidya ◽  
Shweta Jain ◽  
Sanjeev Sahu ◽  
Pankaj Kumar Jain ◽  
Kamla Pathak ◽  
...  
Keyword(s):  
Anticancer Agents ◽  
Dna Methyltransferase ◽  
Leucine Zipper ◽  
Molecular Mechanisms ◽  
Resistance Mechanisms ◽  
Sphingosine Kinase 2 ◽  
Family Protein ◽  
Rational Combination ◽  
Protein Kinase Akt ◽  
Parp 1

Traditional cancer treatment includes surgery, chemotherapy, radiotherapy and immunotherapy that are clinically beneficial, but are associated with drawbacks such as drug resistance and side effects. In quest for better treatment, many new molecular targets have been introduced in the last few decades. Finding new molecular mechanisms encourages researchers to discover new anticancer agents. Exploring the mechanism of action also facilitates anticipation of potential resistance mechanisms and optimization of rational combination therapies. The write up describes the leading molecular mechanisms for cancer therapy, including mTOR, tyrosine Wee1 kinase (WEE1), Janus kinases, PI3K/mTOR signaling pathway, serine/threonine protein kinase AKT, checkpoint kinase 1 (Chk1), maternal embryonic leucine-zipper kinase (MELK), DNA methyltransferase I (DNMT1), poly (ADP-ribose) polymerase (PARP)-1/-2, sphingosine kinase-2 (SK2), pan-FGFR, inhibitor of apoptosis (IAP), murine double minute 2 (MDM2), Bcl-2 family protein and reactive oxygen species 1 (ROS1). Additionally, the manuscript reviews the anticancer drugs currently under clinical trials.

Molecular Mechanisms Underlying the Functions of Cellular Markers Associated with the Phenotype of Cancer Stem Cells

2019 ◽  
Vol 14 (5) ◽  
pp. 405-420 ◽  
Author(s):  
Eduardo Alvarado-Ortiz ◽  
Miguel Á. Sarabia-Sánchez ◽  
Alejandro García-Carrancá
Keyword(s):  
Stem Cells ◽  
Cancer Stem Cells ◽  
Molecular Mechanisms ◽  
Tumor Biology ◽  
Molecular Tools ◽  
Recent Past ◽  
Functional Roles ◽  
Cellular Population ◽  
Cellular Markers ◽  
A Minor

Cancer Stem Cells (CSC) generally constitute a minor cellular population within tumors that exhibits some capacities of normal Stem Cells (SC). The existence of CSC, able to self-renew and differentiate, influences central aspects of tumor biology, in part because they can continue tumor growth, give rise to metastasis, and acquire drug and radioresistance, which open new avenues for therapeutics. It is well known that SC constantly interacts with their niche, which includes mesenchymal cells, extracellular ligands, and the Extra Cellular Matrix (ECM). These interactions regularly lead to homeostasis and maintenance of SC characteristics. However, the exact participation of each of these components for CSC maintenance is not clear, as they appear to be context- or cell-specific. In the recent past, surface cellular markers have been fundamental molecular tools for identifying CSC and distinguishing them from other tumor cells. Importantly, some of these cellular markers have been shown to possess functional roles that affect central aspects of CSC. Likewise, some of these markers can participate in regulating the interaction of CSC with their niche, particularly the ECM. We focused this review on the molecular mechanisms of surface cellular markers commonly employed to identify CSC, highlighting the signaling pathways and mechanisms involved in CSC-ECM interactions, through each of the cellular markers commonly used in the study of CSC, such as CD44, CD133, CD49f, CD24, CXCR4, and LGR5. Their presence does not necessarily implicate them in CSC biology.

scholarly journals Advances in the Molecular Mechanisms of Abscisic Acid and Gibberellins Functions in Plants

2021 ◽  
Vol 22 (11) ◽  
pp. 6080
Author(s):  
Víctor Quesada
Keyword(s):  
Abscisic Acid ◽  
Molecular Mechanisms ◽  
Original Research ◽  
Special Issue ◽  
Research Papers

In this special issue entitled, “Advances in the Molecular Mechanisms of Abscisic Acid and Gibberellins Functions in Plants”, eight articles are collected, with five reviews and three original research papers, which broadly cover different topics on the abscisic acid (ABA) field and, to a lesser extent, on gibberellins (GAs) research [...]

scholarly journals Viral Host Range database, an online tool for recording, analyzing and disseminating virus-host interactions

2021 ◽  
Author(s):  
Quentin Lamy-Besnier ◽  
Bryan Brancotte ◽  
Hervé Ménager ◽  
Laurent Debarbieux
Keyword(s):  
Host Range ◽  
Source Code ◽  
Range Data ◽  
Web Based ◽  
Online Tool ◽  
Experimental Host ◽  
Living World ◽  
Host Interactions ◽  
Experimental Host Range ◽  
Viral Host Range

Abstract Motivation Viruses are ubiquitous in the living world, and their ability to infect more than one host defines their host range. However, information about which virus infects which host, and about which host is infected by which virus, is not readily available. Results We developed a web-based tool called the Viral Host Range database to record, analyze and disseminate experimental host range data for viruses infecting archaea, bacteria and eukaryotes. Availability The ViralHostRangeDB application is available from https://viralhostrangedb.pasteur.cloud. Its source code is freely available from the Gitlab hub of Institut Pasteur (https://gitlab.pasteur.fr/hub/viralhostrangedb).

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