scholarly journals Phenotypic and Genetic Characterization of Temperature-Induced Mutagenesis and Mortality in Cupriavidus metallidurans

2021 ◽  
Vol 12 ◽  
Author(s):  
Rob Van Houdt ◽  
Joachim Vandecraen ◽  
Wietse Heylen ◽  
Natalie Leys ◽  
Pieter Monsieurs ◽  
...  
Keyword(s):  
Normal Growth ◽  
Growth Media ◽  
High Concentration ◽  
Cupriavidus Metallidurans ◽  
Aberrant Phenotype ◽  
Induced Mutagenesis ◽  
Casamino Acids ◽  
Phenotypic And Genetic Characterization

Cupriavidus metallidurans strains display a decreased viability when incubated in rich medium at a temperature of 37°C compared to their normal growth temperature of 30°C, a phenomenon coined “temperature-induced mortality and mutagenesis” (TIMM). To scrutinize this aberrant phenotype further, the contributions of specific inducers and protective agents were determined. Different growth media, including lysogeny broth (LB) and Schatz, and components, including casamino acids, in particular amino acids (proline, cysteine, glycine, glutamine, leucine, histidine and phenylalanine) and ammonium, were found to induce TIMM at 37°C. Sorbitol was found to counteract TIMM. Furthermore, although TIMM is well conserved within the C. metallidurans species, multiple and strain-specific TIMM inducers exist. Twenty-nine percent of the TIMM survivors inherited resistance to TIMM. Whole-genome sequencing of two resistant derivatives revealed an important role of an uncharacterized oxidoreductase, indicating putative metabolic poisoning when grown in high-concentration nitrogen-containing media at 37°C.

scholarly journals Focused ultrasound in neuro-oncology: the role of the Focused Ultrasound Foundation in driving adoption and innovation

2021 ◽  
Author(s):  
Emily C. Whipple ◽  
Camille A. Favero ◽  
Neal F. Kassell
Keyword(s):  
Drug Delivery ◽  
Brain Tumors ◽  
Focused Ultrasound ◽  
Clinical Evidence ◽  
Neurological Injury ◽  
High Concentration ◽  
Potential Applications ◽  
Tumor Agent

Abstract Introduction Intra-arterial (lA) delivery of therapeutic agents across the blood-brain barrier (BBB) is an evolving strategy which enables the distribution of high concentration therapeutics through a targeted vascular territory, while potentially limiting systemic toxicity. Studies have demonstrated lA methods to be safe and efficacious for a variety of therapeutics. However, further characterization of the clinical efficacy of lA therapy for the treatment of brain tumors and refinement of its potential applications are necessary. Methods We have reviewed the preclinical and clinical evidence supporting superselective intraarterial cerebral infusion (SSJACI) with BBB disruption for the treatment of brain tumors. In addition, we review ongoing clinical trials expanding the applicability and investigating the efficacy of lA therapy for the treatment of brain tumors. Results Trends in recent studies have embraced the use of SSIACI and less neurotoxic chemotherapies. The majority of trials continue to use mannitol as the preferred method of hyperosmolar BBB disruption. Recent preclinical and preliminary human investigations into the lA delivery of Bevacizumab have demonstrated its safety and efficacy as an anti-tumor agent both alone and in combination with chemotherapy. Conclusion lA drug delivery may significantly affect the way treatment are delivered to patients with brain tumors, and in particular GBM. With refinement and standardization of the techniques of lA drug delivery, improved drug selection and formulations, and the development of methods to minimize treatment-related neurological injury, lA therapy may offer significant benefits for the treatment of brain tumors.

scholarly journals Phenotypic and genetic characterization of differential galacto-oligosaccharide utilization in Lactobacillus plantarum

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jori Fuhren ◽  
Markus Schwalbe ◽  
Lucía Peralta-Marzal ◽  
Christiane Rösch ◽  
Henk A. Schols ◽  
...  
Keyword(s):  
Lactobacillus Plantarum ◽  
Phenotypic Diversity ◽  
Degree Of Polymerization ◽  
Carbohydrate Utilization ◽  
Potential Health ◽  
Probiotic Strains ◽  
Health Promoting ◽  
Phenotypic And Genetic Characterization

AbstractSeveral Lactobacillus plantarum strains are marketed as probiotics for their potential health benefits. Prebiotics, e.g., galacto-oligosaccharides (GOS), have the potential to selectively stimulate the growth of L. plantarum probiotic strains based on their phenotypic diversity in carbohydrate utilization, and thereby enhance their health promoting effects in the host in a strain-specific manner. Previously, we have shown that GOS variably promotes the strain-specific growth of L. plantarum. In this study we investigated this variation by molecular analysis of GOS utilization by L. plantarum. HPAEC-PAD analysis revealed two distinct GOS utilization phenotypes in L. plantarum. Linking these phenotypes to the strain-specific genotypes led to the identification of a lac operon encoding a β-galactosidase (lacA), a permease (lacS), and a divergently oriented regulator (lacR), that are predicted to be involved in the utilization of higher degree of polymerization (DP) constituents present in GOS (specifically DP of 3–4). Mutation of lacA and lacS in L. plantarum NC8 resulted in reduced growth on GOS, and HPAEC analysis confirmed the role of these genes in the import and utilization of higher-DP GOS constituents. Overall, the results enable the design of highly-selective synbiotic combinations of L. plantarum strain-specific probiotics and specific GOS-prebiotic fractions.

scholarly journals Salt-Induced Stress Stimulates a Lipoteichoic Acid-Specific Three-Component Glycosylation System inStaphylococcus aureus

2018 ◽  
Vol 200 (12) ◽  
Author(s):  
Kelvin Kho ◽  
Timothy C. Meredith
Keyword(s):  
Staphylococcus Aureus ◽  
Sigma Factor ◽  
Cell Envelope ◽  
Normal Growth ◽  
Lipoteichoic Acid ◽  
Growth Conditions ◽  
Growth Media ◽  
Alternative Sigma Factor ◽  
Content Type

ABSTRACTLipoteichoic acid (LTA) inStaphylococcus aureusis a poly-glycerophosphate polymer anchored to the outer surface of the cell membrane. LTA has numerous roles in cell envelope physiology, including regulating cell autolysis, coordinating cell division, and adapting to environmental growth conditions. LTA is often further modified with substituents, includingd-alanine and glycosyl groups, to alter cellular function. While the genetic determinants ofd-alanylation have been largely defined, the route of LTA glycosylation and its role in cell envelope physiology have remained unknown, in part due to the low levels of basal LTA glycosylation inS. aureus. We demonstrate here thatS. aureusutilizes a membrane-associated three-component glycosylation system composed of an undecaprenol (Und)N-acetylglucosamine (GlcNAc) charging enzyme (CsbB; SAOUHSC_00713), a putative flippase to transport loaded substrate to the outside surface of the cell (GtcA; SAOUHSC_02722), and finally an LTA-specific glycosyltransferase that adds α-GlcNAc moieties to LTA (YfhO; SAOUHSC_01213). We demonstrate that this system is specific for LTA with no cross recognition of the structurally similar polyribitol phosphate containing wall teichoic acids. We show that while wild-typeS. aureusLTA has only a trace of GlcNAcylated LTA under normal growth conditions, amounts are raised upon either overexpressing CsbB, reducing endogenousd-alanylation activity, expressing the cell envelope stress responsive alternative sigma factor SigB, or by exposure to environmental stress-inducing culture conditions, including growth media containing high levels of sodium chloride.IMPORTANCEThe role of glycosylation in the structure and function ofStaphylococcus aureuslipoteichoic acid (LTA) is largely unknown. By defining key components of the LTA three-component glycosylation pathway and uncovering stress-induced regulation by the alternative sigma factor SigB, the role ofN-acetylglucosamine tailoring during adaptation to environmental stresses can now be elucidated. As thedltand glycosylation pathways compete for the same sites on LTA and induction of glycosylation results in decreasedd-alanylation, the interplay between the two modification systems holds implications for resistance to antibiotics and antimicrobial peptides.

scholarly journals Removal of COD & NH3 from Produced Water using Modified Horizontal Subsurface Flow Constructed Wetlands (HSCW)

REAKTOR ◽  
2018 ◽  
Vol 18 (03) ◽  
pp. 166
Author(s):  
Agus Jatnika Effendi ◽  
Regi Risman Sandi
Keyword(s):  
Produced Water ◽  
Anaerobic Bacteria ◽  
Subsurface Flow ◽  
Typha Latifolia ◽  
Oil Field ◽  
Elevated Concentration ◽  
High Concentration ◽  
Horizontal Subsurface Flow

It is very common that COD and NH3 are found in Produced Water with elevated concentration. One proven technology that is capable in removing organic substances and nutrients, is Horizontal Subsurface Flow Constructed Wetland (HSCW). Based on characterization of produced water from one oil field in Indonesia, it was shown that COD and NH3 were found to exceed the threshold limit stated in Ministry of Environmental Decree no. 19 Year 2010. Modified HSCWs were developed in order to treat produced water containing high concentration of COD and NH3 and allowing anaerobic process to occur in the reactor. The HSCWs were planted by three different species; they were Sagittaria palaefolia (Jasmine Water), Scirpus grossus (Mensiang), and Typha latifolia (Walingi). Organic loading rates (OLRs) to the HSCWs reactor were varied from 7.2 to 72 gr COD/m2.day. It was found that HSCW planted with Typha latifolia had the highest removal efficiency for both COD and NH3 when the OLR was set at 14.4 gr COD/m2.day. Anaerobic bacteria were found in high number indicating that these bacteria involved actively in removing pollutants containing in produced water. However, further microbiology study should be performed in order to determine the role of anaerobic bacteria.

scholarly journals Integrating Molecular Network and Culture Media Variation to Explore the Production of Bioactive Metabolites by Vibrio diabolicus A1SM3

Marine Drugs ◽  
2019 ◽  
Vol 17 (4) ◽  
pp. 196
Author(s):  
Natalia Conde-Martínez ◽  
Anelize Bauermeister ◽  
Alan Pilon ◽  
Norberto Lopes ◽  
Edisson Tello
Keyword(s):  
Culture Media ◽  
Molecular Network ◽  
Bioactive Metabolites ◽  
Growth Media ◽  
Main Compound ◽  
Carbon And Nitrogen ◽  
The Media ◽  
Casamino Acids ◽  
Human Lung Cell Line

Vibrio diabolicus A1SM3 strain was isolated from a sediment sample from Manaure Solar Saltern in La Guajira and the produced crude extracts have shown antibacterial activity against methicillin-resistant Staphylococcus aureus and cytotoxic activity against human lung cell line. Thus, the aim of this research was to identify the main compound responsible for the biological activity observed and to systematically study how each carbon and nitrogen source in the growth media, and variation of the salinity, affect its production. For the characterization of the bioactive metabolites, 15 fractions obtained from Vibrio diabolicus A1SM3 crude extract were analyzed by HPLC-MS/MS and their activity was established. The bioactive fractions were dereplicated with Antibase and Marinlit databases, which combined with nuclear magnetic resonance (NMR) spectra and fragmentation by MS/MS, led to the identification of 2,2-di(3-indolyl)-3-indolone (isotrisindoline), an indole-derivative antibiotic, previously isolated from marine organisms. The influence of the variations of the culture media in isotrisindoline production was established by molecular network and MZmine showing that the media containing starch and peptone at 7% NaCl was the best culture media to produce it. Also, polyhydroxybutyrates (PHB) identification was established by MS/MS mainly in casamino acids media, contributing to the first report on PHB production by this strain.

scholarly journals Insulin increases the density of potassium channels in white adipocytes: possible role in adipogenesis

2002 ◽  
Vol 174 (2) ◽  
pp. 299-307 ◽  
Author(s):  
MP Ramirez-Ponce ◽  
JC Mateos ◽  
JA Bellido
Keyword(s):  
Potassium Channels ◽  
Normal Growth ◽  
Potassium Currents ◽  
High Concentration ◽  
Differentiated Cells ◽  
White Adipocytes ◽  
Cell Proliferation And Differentiation ◽  
Proliferation And Differentiation ◽  
Inhibition Of Differentiation

We studied the potassium currents in white adipocytes obtained by culturing preadipocytes from rat epididymal tissue, both with insulin (WA(i)) and without insulin (WA(o)), in order to test the role of insulin in the development of voltage-gated potassium channels (K(v)) during adipogenesis. Occasionally, very small potassium currents (I(K,V)) were present in preadipocytes; however these currents were measured in all differentiated cells (adipocytes). WA(i) exhibited greater macroscopic potassium currents than WA(o) with no apparent differences in kinetics or voltage dependence. The current density (pA/ micro m(2)) calculated in WA(i) was higher than in WA(o). Currents were blocked by millimolar concentrations of tetrethylamonium (TEA). The effect of insulin on adipogenesis, both with and without TEA, was analysed. Four days without insulin and three days with insulin were necessary to increase the total number of cells in culture by 2.5-fold. Insulin increased the number of differentiated cells by 73.5%. Cell proliferation and differentiation were inhibited by TEA. Proliferation was affected only by high concentration of TEA. Inhibition of differentiation was dose dependent, with the concentration necessary for half-block similar to the IC(50) values to block potassium channels. These results suggest that insulin increases the density of K(v) and that these channels may be necessary for the normal growth of white adipocytes in culture.

scholarly journals The antimicrobial activity of the macrophage metabolite itaconate is synergistic with acidity

2020 ◽  
Author(s):  
Dustin Duncan ◽  
Andréanne Lupien ◽  
Marcel A. Behr ◽  
Karine Auclair
Keyword(s):  
Itaconic Acid ◽  
Growth Media ◽  
Activated Macrophages ◽  
Bacterial Strains ◽  
High Concentration ◽  
Differential Growth ◽  
New Strategy ◽  
Acidic Conditions

AbstractThe production of itaconate by macrophages was only discovered in 2011. A rapidly increasing number of studies have since revealed essential biological roles for itaconate, ranging from antimicrobial to immunomodulator. Itaconate has been estimated to reach low-millimolar concentrations in activated macrophages, including those within infected lungs and brains, whereas itaconate’s MIC towards several bacterial strains were measured to be in the low-to-mid-millimolar range, casting some doubts on the antibacterial role of itaconate in vivo. Several of these investigations, in particular those measuring MIC values of itaconate or itaconic acid, have however tended to ignore the high acidity of this small diacid (pKas 3.85 and 5.45), thereby potentially biasing the MIC measurements. We report herein that: 1) at high concentration, itaconic acid can significantly reduce the pH of growth media; 2) the antibacterial activity of itaconate increases in a synergistic manner with acidity; 3) this synergistic effect is not simply due to increased permeability of monoanionic itaconate; 4) considering that the MIC of itaconate is many fold lower under acidic conditions for all strains tested, itaconate may serve an antimicrobial role, particularly in acidic vesicles such as the phagolysosome; and 5) differential growth behavior in the presence of disodium itaconate versus itaconic acid may serve to rapidly screen bacterial strains for their ability to metabolize itaconate. Our results further support the hypothesis that inhibitors of itaconate degradation in bacteria may provide a new strategy to treat infections.

Digital x-ray mapping of nanometer-size supported bimetallic catalysts

1988 ◽  
Vol 46 ◽  
pp. 530-531
Author(s):  
L. T. Germinario
Keyword(s):  
Background Radiation ◽  
Metal Cluster ◽  
Single Element ◽  
Beam Diameter ◽  
X Rays ◽  
X Ray ◽  
Major Interest ◽  
Induced Changes

Understanding the role of metal cluster composition in determining catalytic selectivity and activity is of major interest in heterogeneous catalysis. The electron microscope is well established as a powerful tool for ultrastructural and compositional characterization of support and catalyst. Because the spatial resolution of x-ray microanalysis is defined by the smallest beam diameter into which the required number of electrons can be focused, the dedicated STEM with FEG is the instrument of choice. The main sources of errors in energy dispersive x-ray analysis (EDS) are: (1) beam-induced changes in specimen composition, (2) specimen drift, (3) instrumental factors which produce background radiation, and (4) basic statistical limitations which result in the detection of a finite number of x-ray photons. Digital beam techniques have been described for supported single-element metal clusters with spatial resolutions of about 10 nm. However, the detection of spurious characteristic x-rays away from catalyst particles produced images requiring several image processing steps.

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