Conserved Evolutionary Trajectory Can Be Perturbed to Prevent Resistance Evolution under Norfloxacin Pressure by Forcing on Alternate Evolutionary Paths.

Antibiotic resistance is a pressing health issue, with the emergence of resistance in bacteria outcompeting the discovery of novel drug candidates. While many studies have used Adaptive Laboratory Evolution (ALE) to understand the determinants of resistance, the influence of the drug dosing profile on the evolutionary trajectory remains understudied. In this study, we employed ALE on exposed to various concentrations of Norfloxacin using both cyclic constant and stepwise increasing drug dosages to examine their impact on the resistance mechanisms selected.

Enhancement of Antimycobacterial Activity of Rifampicin Using Mannose-Anchored Lipid Nanoparticles against Intramacrophage Mycobacteria.

Tuberculosis treatment requires a multidrug combination for the long-term, associated with adverse effects which lead to nonpatient compliance and the emergence of drug-resistant strains. Thus, mannose-anchored rifampicin-loaded solid lipid nanoparticles (M-RIF-SLNs) were developed to enhance the effect of rifampicin by selectively delivering to the macrophage, which led to the high intracellular killing of mycobacteria. The synthesized M-RIF-SLNs show a particle size of ∼100 nm and a drug loading of ∼8%.

The Extent of Antimicrobial Resistance Due to Efflux Pump Regulation.

A key mechanism driving antimicrobial resistance (AMR) stems from the ability of bacteria to up-regulate efflux pumps upon exposure to drugs. The resistance gained by this up-regulation is pliable because of the tight regulation of efflux pump levels. This leads to temporary enhancement in survivability of bacteria due to higher efflux pump levels in the presence of antibiotics, which can be reversed when the cells are no longer exposed to the drug.

Involvement of the SCO3366 efflux pump from S. coelicolor in rifampicin resistance and its regulation by a TetR regulator.

Overexpression of efflux pumps represents a key mechanism of resistance in bacteria. Soil bacteria such as Streptomyces harbour a vast array of efflux genes that are transcriptionally silent under laboratory conditions. However, dissemination of many of these genes into clinical pathogens via horizontal gene transfer results in conferring resistance to multiple drugs.

Potentiating the Anti-Tuberculosis Efficacy of Peptide Nucleic Acids through Combinations with Permeabilizing Drugs.

The emergence of antimicrobial resistance warrants for the development of improved treatment approaches. In this regard, peptide nucleic acids (PNAs) have shown great promise, exhibiting antibiotic properties through the targeting of cellular nucleic acids. We aimed to study the efficacy of PNA as an anti-tuberculosis agent.

pH-driven enhancement of anti-tubercular drug loading on iron oxide nanoparticles for drug delivery in macrophages.

Nanoparticle deployment in drug delivery is contingent upon controlled drug loading and a desired release profile, with simultaneous biocompatibility and cellular targeting. Iron oxide nanoparticles (IONPs), being biocompatible, are used as drug carriers. However, to prevent aggregation of bare IONPs, they are coated with stabilizing agents.

The Mycobacterial Efflux Pump EfpA Can Induce High Drug Tolerance to Many Antituberculosis Drugs, Including Moxifloxacin, in Mycobacterium smegmatis.

Active efflux of drugs across the membrane is a major survival strategy of bacteria against many drugs. In this work, we characterize an efflux pump, EfpA, from the major facilitator superfamily, that is highly conserved among both slow-growing and fast-growing Mycobacterium species and has been found to be upregulated in many clinical isolates of Mycobacterium tuberculosis. The gene encoding EfpA from Mycobacterium smegmatis was overexpressed under the control of both a constitutive and an inducible promoter.

A Major Facilitator Superfamily (MFS) Efflux Pump, SCO4121, from Streptomyces coelicolor with Roles in Multidrug Resistance and Oxidative Stress Tolerance and Its Regulation by a MarR Regulator.

Overexpression of efflux pumps is one of the major determinants of resistance in bacteria. species harbor a large array of efflux pumps that are transcriptionally silenced under laboratory conditions. However, their dissemination results in multidrug resistance in different clinical pathogens.

PNA-mediated efflux inhibition as a therapeutic strategy towards overcoming drug resistance in Mycobacterium smegmatis.

The emergence of antibiotic-resistant strains of Mycobacterium tuberculosis and the decelerating development of new and effective antibiotics has impaired the treatment of tuberculosis (TB). Efflux pump inhibitors (EPIs) have the potential to improve the efficacy of existing anti-TB drugs although with toxicity limitations. Peptide nucleic acids (PNAs), oligonucleotide mimics, by virtue of their high nucleic acid binding specificity have the capability to overcome this drawback.

Ethanol in Combination with Oxidative Stress Significantly Impacts Mycobacterial Physiology.

Here, we investigate the mycobacterial response to the combined stress of an organic oxidant (cumene hydroperoxide [CHP]) and a solvent (ethanol). To understand the interaction between the two stressors, we treated cells to a range of ethanol concentrations (2.5% to 10% [vol/vol]) in combination with a subinhibitory concentration of 1 mM CHP.

Enhancing titers and productivity of rCHO clones with a combination of an optimized fed-batch process and ER-stress adaptation.

To increase the productivity of rCHO cells, many cell engineering approaches have been demonstrated that over-express or knockout a specific gene to achieve increased titers. In this work, we present an alternate approach, based on the concept of evolutionary adaptation, to achieve cells with higher titers. rCHO cells, producing a monoclonal antibody, are adapted to ER-stress, by continuous culturing under increasing concentration of tunicamycin.

Repurposing artemisinin as an anti-mycobacterial agent in synergy with rifampicin.

The current anti-TB treatment consists of a prolonged multi-drug therapy. Interventional strategies are required to reduce the chemotherapeutic load. In this regard, we have previously identified a synergistic interaction between hydroperoxides and rifampicin.

Distinct transcriptomic response of S. coelicolor to ciprofloxacin in a nutrient-rich environment.

With the rising threat of anti-microbial resistance (AMR), there is an urgent need to enhance efficacy of existing antibiotics. Understanding the myriad mechanisms through which bacteria evade these drugs would be of immense value to designing novel strategies against them. Streptomyces coelicolor A3(2) M145 belongs to the actinomyctes species that are responsible for more than two-thirds of antibiotics.

The Familial α-Synuclein A53E Mutation Enhances Cell Death in Response to Environmental Toxins Due to a Larger Population of Oligomers.

Amyloid formation of α-synuclein (α-Syn) and its familial mutations are directly linked with Parkinson's disease (PD) pathogenesis. Recently, a new familial α-Syn mutation (A53E) was discovered, associated with an early onset aggressive form of PD, which delays α-Syn aggregation. When we overexpressed wild-type (WT) and A53E proteins in cells, showed neither toxicity nor aggregate formation, suggesting merely overexpression may not recapitulate the PD phenotype in cell models.

Synergistic Response of Rifampicin with Hydroperoxides on : A Mechanistic Study.

Prolonged chemotherapy as well as rapid development of antimicrobial resistance are two of the major concerns for treatment of mycobacterial infections. To enhance the effectiveness of current drug regimens, search for compounds having synergistic interaction with anti-mycobacterial drugs has become indispensable. Here, we have investigated the intervention by oxidative stress, a major factor in mycobacterial pathogenesis, in combination with rifampicin (RIF), a first-line drug used against .

Activation of unfolded protein response pathway is important for valproic acid mediated increase in immunoglobulin G productivity in recombinant Chinese hamster ovary cells.

Process engineering to improve product quality and titers is gaining importance at late-stage cell culture process development. Valproic acid, a US Food and Drug Administration-approved histone deacetylase (HDAC) inhibitor, has been shown to improve cell culture performance with higher productivities and minimal effect on the product quality. However, the wider physiological impact of valproic acid on recombinant cells has not been investigated till date.

Polyacrylic acid-coated iron oxide nanoparticles for targeting drug resistance in mycobacteria.

The emergence of drug resistance is a major problem faced in current tuberculosis (TB) therapy, representing a global health concern. Mycobacterium is naturally resistant to most drugs due to export of the latter outside bacterial cells by active efflux pumps, resulting in a low intracellular drug concentration. Thus, development of agents that can enhance the effectiveness of drugs used in TB treatment and bypass the efflux mechanism is crucial.

Dynamics of unfolded protein response in recombinant CHO cells.

Genes in the protein secretion pathway have been targeted to increase productivity of monoclonal antibodies in Chinese hamster ovary cells. The results have been highly variable depending on the cell type and the relative amount of recombinant and target proteins. This paper presents a comprehensive study encompassing major components of the protein processing pathway in the endoplasmic reticulum (ER) to elucidate its role in recombinant cells.

Transcriptomic study of ciprofloxacin resistance in Streptomyces coelicolor A3(2).

Soil organisms exhibit resistance to a wide range of antibiotics as they either need to protect themselves from endogenous antibiotics or from those present in their soil environment. The soil could serve as a reservoir for resistance mechanisms that have already emerged or have the potential to emerge in clinically important bacteria. Streptomyces coelicolor, a non-pathogenic soil-dwelling organism, is thus used as a model for the study of intrinsic resistance.

Comparative phylogenomics of pathogenic and non-pathogenic mycobacterium.

Mycobacterium species are the source of a variety of infectious diseases in a range of hosts. Genome based methods are used to understand the adaptation of each pathogenic species to its unique niche. In this work, we report the comparison of pathogenic and non-pathogenic Mycobacterium genomes.

Proteomic analysis of Streptomyces coelicolor in response to Ciprofloxacin challenge.

Unlabelled: Multi-drug tolerance is an important phenotypic property that complicates treatment of infectious diseases and reshapes drug discovery. Hence a systematic study of the origins and mechanisms of resistance shown by microorganisms is imperative. Since soil-dwelling bacteria are constantly challenged with a myriad of antibiotics, they are potential reservoirs of resistance determinants that can be mobilized into pathogens over a period of time.

All-trans retinoic acid loaded block copolymer nanoparticles efficiently induce cellular differentiation in HL-60 cells.

All-trans retinoic acid (atRA) is used in the differentiation therapy of Acute Promyelocytic Leukemia. However, its therapeutic success is limited by the appearance of relapse and recalcitrant cases, poor aqueous solubility and high degradability. In the current work, we prepared two types of atRA-loaded copolymer nanoparticles - PL1RA and PC1RA, based on poly(ethyleneglycol) (PEG)-poly(l-lactide) and PEG-poly(ε-caprolactone), respectively.

Convergent transcription in the butyrolactone regulon in Streptomyces coelicolor confers a bistable genetic switch for antibiotic biosynthesis.

cis-encoded antisense RNAs (cis asRNA) have been reported to participate in gene expression regulation in both eukaryotic and prokaryotic organisms. Its presence in Streptomyces coelicolor has also been reported recently; however, its role has yet to be fully investigated. Using mathematical modeling we explore the role of cis asRNA produced as a result of convergent transcription in scbA-scbR genetic switch.

A bistable gene switch for antibiotic biosynthesis: the butyrolactone regulon in Streptomyces coelicolor.

Many microorganisms, including bacteria of the class Streptomycetes, produce various secondary metabolites including antibiotics to gain a competitive advantage in their natural habitat. The production of these compounds is highly coordinated in a population to expedite accumulation to an effective concentration. Furthermore, as antibiotics are often toxic even to their producers, a coordinated production allows microbes to first arm themselves with a defense mechanism to resist their own antibiotics before production commences.

Genome-wide transcriptome analysis reveals that a pleiotropic antibiotic regulator, AfsS, modulates nutritional stress response in Streptomyces coelicolor A3(2).

Background: A small "sigma-like" protein, AfsS, pleiotropically regulates antibiotic biosynthesis in Streptomyces coelicolor. Overexpression of afsS in S. coelicolor and certain related species causes antibiotic stimulatory effects in the host organism.