Mechanical feedback promotes bacterial adaptation to antibiotics

Hfq is a bacterial regulator with key roles in gene expression. The protein notably regulates translation efficiency and RNA decay in Gram-negative bacteria, thanks to its binding to small regulatory noncoding RNAs. This property is of primary importance for bacterial adaptation and survival in hosts. Small RNAs and Hfq are, for instance, involved in the response to antibiotics. Previous work has shown that the E. coli Hfq C-terminal region (Hfq-CTR) self-assembles into an amyloid structure. It was also demonstrated that the green tea compound EpiGallo Catechin Gallate (EGCG) binds to Hfq-CTR amyloid fibrils and remodels them into nonamyloid structures. Thus, compounds that target the amyloid region of Hfq may be used as antibacterial agents. Here, we show that another compound that inhibits amyloid formation, apomorphine, may also serve as a new antibacterial. Our results provide an alternative in order to repurpose apomorphine, commonly used in the treatment of Parkinson’s disease, as an antibiotic to block bacterial adaptation to treat infections.

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Bioleaching of Pyrrhotite with Bacterial Adaptation and Biological Oxidation for Iron Recovery

Metals ◽

10.3390/met11020295 ◽

2021 ◽

Vol 11 (2) ◽

pp. 295

Author(s):

Bong-Ju Kim ◽

Yong-Kwon Koh ◽

Jang-Soon Kwon

Keyword(s):

Mine Drainage ◽

Mine Waste ◽

Point Of Zero Charge ◽

Biological Oxidation ◽

Indigenous Bacteria ◽

Bacterial Adaptation ◽

Valuable Metals ◽

Initial Ph ◽

Dominant Member ◽

Corrosion Pits

The microbially mediated recovery of valuable metals contained in mining waste presents an economical alternative to conventional hydrometallurgical processes. In order to investigate the effect of bacterial adaptation and biological oxidation on bioleaching, the microbially mediated bioleaching of a pyrrhotite sample from mine waste, with indigenous bacteria existing in acid mine drainage, was studied. The indigenous bacteria were sub-cultured repeatedly for iron adaptation, and Acidithiobacillus ferrooxidans was identified as the dominant member of the microbial consortium. The point of zero charge (PZC) of pyrrhotite sampled from mine waste was determined as 3.0. The performance of bioleaching by contact and non-contact biological oxidation was compared by conducting bioleaching under different initial pH (pHini) conditions (2.8 and 3.2). Negatively charged bacteria could be attached onto the pyrrhotite, which has a positive surface charge at lower pHini (2.8) than the PZC (3.0). Bacteria attachment and corrosion pits on the surface of the pyrrhotite residues were observed at pHini of 2.8. Under bacteria-adapted conditions, the leaching concentration of Fe (44.2 mg/L) at pHini of 2.8 was 2.1 times greater than that (21.3 mg/L) at pHini of 3.2. Under non-adapted bacteria conditions, the extent of Fe leaching was not significantly different between the pHini of 2.8 and 3.2. This could be attributed to the fact that the adapted bacteria could more easily attach onto the pyrrhotite surfaces at pHini 2.8, allowing contact biological oxidation during the bioleaching experiments. We demonstrate here that the bioleaching of pyrrhotite could increase Fe recovery through bacterial adaptation and contact biological oxidation.

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Amoeba host-Legionellasynchronization of amino acid auxotrophy and its role in bacterial adaptation and pathogenic evolution

Environmental Microbiology ◽

10.1111/1462-2920.12290 ◽

2013 ◽

Vol 16 (2) ◽

pp. 350-358 ◽

Cited By ~ 33

Author(s):

Christopher T. D. Price ◽

Ashley M. Richards ◽

Juanita E. Von Dwingelo ◽

Hala A. Samara ◽

Yousef Abu Kwaik

Keyword(s):

Amino Acid ◽

Bacterial Adaptation ◽

Pathogenic Evolution

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The Crossroads between RAS and RHO Signaling Pathways in Cellular Transformation, Motility and Contraction

Genes ◽

10.3390/genes12060819 ◽

2021 ◽

Vol 12 (6) ◽

pp. 819

Author(s):

Olga Soriano ◽

Marta Alcón-Pérez ◽

Miguel Vicente-Manzanares ◽

Esther Castellano

Keyword(s):

Signaling Pathways ◽

Actin Polymerization ◽

Mapk Pathway ◽

Human Cancer ◽

Cellular Transformation ◽

Dependent Manner ◽

Rho Proteins ◽

Filament Assembly ◽

Multiple Signaling ◽

Mechanical Feedback

Ras and Rho proteins are GTP-regulated molecular switches that control multiple signaling pathways in eukaryotic cells. Ras was among the first identified oncogenes, and it appears mutated in many forms of human cancer. It mainly promotes proliferation and survival through the MAPK pathway and the PI3K/AKT pathways, respectively. However, the myriad proteins close to the plasma membrane that activate or inhibit Ras make it a major regulator of many apparently unrelated pathways. On the other hand, Rho is weakly oncogenic by itself, but it critically regulates microfilament dynamics; that is, actin polymerization, disassembly and contraction. Polymerization is driven mainly by the Arp2/3 complex and formins, whereas contraction depends on myosin mini-filament assembly and activity. These two pathways intersect at numerous points: from Ras-dependent triggering of Rho activators, some of which act through PI3K, to mechanical feedback driven by actomyosin action. Here, we describe the main points of connection between the Ras and Rho pathways as they coordinately drive oncogenic transformation. We emphasize the biochemical crosstalk that drives actomyosin contraction driven by Ras in a Rho-dependent manner. We also describe possible routes of mechanical feedback through which myosin II activation may control Ras/Rho activation.

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Genomic Analysis of Citrobacter Portucalensis Sb-2 Identifies a Phage Predation Driven Metalloid Resistance

10.21203/rs.3.rs-470342/v1 ◽

2021 ◽

Author(s):

Yanshuang Yu ◽

Zhenchen Xie ◽

Jigang Yang ◽

Jinxuan Liang ◽

YuanPing Li ◽

...

Keyword(s):

Genetic Diversity ◽

Gene Transfer ◽

Horizontal Gene Transfer ◽

Significant Role ◽

Genome Analysis ◽

Extreme Environments ◽

Genomic Analysis ◽

Resistant Bacterium ◽

Bacterial Adaptation ◽

Resistance Determinants

Abstract Bacterial adaptation to extreme environments is often mediated by horizontal gene transfer (HGT). At the same time, phage mediated HGT for conferring bacterial arsenite and antimonite resistance has not been documented before. In this study, a highly arsenite and antimonite resistant bacterium, C. portucalensis strain Sb-2, was isolated and subsequent genome analysis showed that putative arsenite and antimonite resistance determinants were flanked or embedded by prophages. We predict these phage-mediated resistances play a significant role in maintaining genetic diversity within the genus of Citrobacter and are responsible for endowing the corresponding resistances to C. portucalensis strain Sb-2.

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The Influence of Chemical and Mechanical Feedback on Ventilatory Pattern in a Model of the Central Respiratory Pattern Generator

Advances in Experimental Medicine and Biology - Modeling and Control of Ventilation ◽

10.1007/978-1-4615-1933-1_5 ◽

1995 ◽

pp. 23-28 ◽

Cited By ~ 2

Author(s):

K. A. E. Geitz ◽

D. W. Richter ◽

A. Gottschalk

Keyword(s):

Pattern Generator ◽

Respiratory Pattern ◽

Ventilatory Pattern ◽

Mechanical Feedback

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The statistics of noisy growth with mechanical feedback in elastic tissues

10.1101/426361 ◽

2018 ◽

Author(s):

Ojan Khatib Damavandi ◽

David K. Lubensky

Keyword(s):

Tissue Growth ◽

Fundamental Aspect ◽

Isotropic Case ◽

Anisotropic Growth ◽

Clone Size ◽

Density Correlation ◽

Precise Control ◽

Growth Modes ◽

Elastic Sheets ◽

Mechanical Feedback

Tissue growth is a fundamental aspect of development and is intrinsically noisy. Stochasticity has important implications for morphogenesis, precise control of organ size, and regulation of tissue composition and heterogeneity. Yet, the basic statistical properties of growing tissues, particularly when growth induces mechanical stresses that can in turn affect growth rates, have received little attention. Here, we study the noisy growth of elastic sheets subject to mechanical feedback. Considering both isotropic and anisotropic growth, we find that the density-density correlation function shows power law scaling. We also consider the dynamics of marked, neutral clones of cells. We find that the areas (but not the shapes) of two clones are always statistically independent, even when they are adjacent. For anisotropic growth, we show that clone size variance scales like the average area squared and that the mode amplitudes characterizing clone shape show a slow 1/n decay, where n is the mode index. This is in stark contrast to the isotropic case, where relative variations in clone size and shape vanish at long times. The high variability in clone statistics observed in anisotropic growth is due to the presence of two soft modes—growth modes that generate no stress. Our results lay the groundwork for more in-depth explorations of the properties of noisy tissue growth in specific biological contexts.

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