Impact of growth environment and physiological state on metal immobilization byPseudomonas aeruginosaPAO1

2010 ◽  
Vol 56 (7) ◽  
pp. 527-538 ◽  
Author(s):  
Ryan C. Hunter ◽  
Vernon R. Phoenix ◽  
Anuradha Saxena ◽  
Terry J. Beveridge
Keyword(s):  
Metal Binding ◽  
Physiological State ◽  
Growth Conditions ◽  
Spectrophotometric Analysis ◽  
Cell Physiology ◽  
Growth Environment ◽  
Bacterial Surface ◽  
Metal Interactions ◽  
Metal Immobilization ◽  
In Cells

Environmental growth conditions and cell physiology have the potential to influence bacterial surface–metal interactions in both planktonic and biofilm systems. Here, Pseudomonas aeruginosa was studied to determine the influence of these factors (pH, redox potential, and active respiration) on surface electrostatics and metal immobilization. Acid–base titrations revealed a decrease in ionizable ligands at pKa5 (putative carboxyls) in cells grown below pH 6.2 and in cells grown anaerobically relative to cells grown under oxic and circumneutral pH conditions. This observation correlates with Western immunoblotting assays that revealed a reduction in carboxylated B-band lipopolysaccharide in these cells. Furthermore, spectrophotometric analysis revealed a decrease in zinc, copper, and iron immobilization in these cells, suggesting that lipopolysaccharide modification in response to environmental stimuli influences metal binding. The effect of active versus inactive metabolism on metal adsorption was also examined using respiration inhibitors carbonyl cyanide m-chlorophenylhydrazone and sodium azide. Cells treated with these compounds bound more zinc, copper, and iron than untreated controls, suggesting proton extrusion through respiration competes with metal cations for reactive groups on the cell surface. Accumulation of gold did not show the same trend, and transmission electron microscopy studies confirmed it was not a surface-mediated process. These results suggest that variations in growth environment and cell physiology influence metal accumulation by bacterial cell surfaces and may help to explain discontinuous accumulation of metal observed throughout microbial communities.

Localization and quantification of endoplasmic reticulum Ca(2+)-ATPase isoform transcripts

1995 ◽  
Vol 269 (3) ◽  
pp. C775-C784 ◽  
Author(s):  
K. D. Wu ◽  
W. S. Lee ◽  
J. Wey ◽  
D. Bungard ◽  
J. Lytton
Keyword(s):  
Endoplasmic Reticulum ◽  
Critical Role ◽  
Qualitative Assessment ◽  
Cell Physiology ◽  
Striated Muscles ◽  
Physiological Processes ◽  
Alternatively Spliced ◽  
Spleen Lymphocytes ◽  
Fast Twitch ◽  
In Cells

The Ca(2+)-adenosinetriphosphatase pump of the sarcoplasmic or endoplasmic reticulum (SERCA) plays a critical role in Ca2+ signaling and homeostasis in all cells and is encoded by a family of homologous and alternatively spliced genes. To understand more clearly the role the different isoforms play in cell physiology, we have undertaken a quantitative and qualitative assessment of the tissue distribution of transcripts encoding each SERCA isoform. SERCA1 expression is restricted to fast-twitch striated muscles, SERCA2a to cardiac and slow-twitch striated muscles, whereas SERCA2b is ubiquitously expressed. SERCA3 is expressed most abundantly in large and small intestine, thymus, and cerebellum and at lower levels in spleen, lymph node, and lung. In situ hybridization analyses revealed SERCA3 transcripts in cells of the intestinal crypt, the thymic cortex, and Purkinje cells in cerebellum. In addition, SERCA3 was expressed abundantly in isolated rat spleen lymphocytes, in various murine lymphoid cell lines, and in primary cultured microvascular endothelial cells. This analysis demonstrates that SERCA3 is expressed selectively in cells in which Ca2+ signaling plays a critical and sensitive role in regulating physiological processes.

scholarly journals A model for variable phytoplankton stoichiometry based on cell protein regulation

2013 ◽  
Vol 10 (2) ◽  
pp. 3241-3279
Author(s):  
J. A. Bonachela ◽  
S. D. Allison ◽  
A. C. Martiny ◽  
S. A. Levin
Keyword(s):  
Physiological State ◽  
Single Point ◽  
Nutrient Content ◽  
Growth Conditions ◽  
Marine Phytoplankton ◽  
Cell Protein ◽  
Nitrogen And Phosphorus ◽  
Elemental Ratios ◽  
Regulatory Processes ◽  
Complex Interactions

Abstract. The elemental ratios of marine phytoplankton emerge from complex interactions between the biotic and abiotic components of the ocean, and reflect the plastic response of individuals to changes in their environment. The stoichiometry of phytoplankton is, thus, dynamic and dependent on the physiological state of the cell. We present a theoretical model for the dynamics of the carbon, nitrogen and phosphorus contents of a phytoplankton population. By representing the regulatory processes controlling nutrient uptake, and focusing on the relation between nutrient content and protein synthesis, our model qualitatively replicates existing experimental observations for nutrient content and ratios. The population described by our model takes up nutrients in proportions that match the input ratios for a broad range of growth conditions. In addition, there are two zones of single-nutrient limitation separated by a wide zone of co-limitation. Within the co-limitation zone, a single point can be identified where nutrients are supplied in an optimal ratio. The existence of a wide co-limitation zone affects the standard picture for species competing for nitrogen and phosphorus, which shows here a much richer pattern. However, additional comprehensive laboratory experiments are needed to test our predictions. Our model contributes to the understanding of the global cycles of oceanic nitrogen and phosphorus, as well as the elemental ratios of these nutrients in phytoplankton populations.

Nutritional biomarkers and machine learning for personalized nutrition applications and health optimization

2021 ◽  
pp. 1-9
Author(s):  
Dimitrios P. Panagoulias ◽  
Dionisios N. Sotiropoulos ◽  
George A. Tsihrintzis
Keyword(s):  
Machine Learning ◽  
Physiological State ◽  
Prediction Method ◽  
Disease Diagnosis ◽  
Classification Model ◽  
Cell Physiology ◽  
Cellular Processes ◽  
General Evaluation ◽  
Model Training ◽  
The One

The doctrine of the “one size fits all” approach in the field of disease diagnosis and patient management is being replaced by a more per patient approach known as “personalized medicine”. In this spirit, biomarkers are key variables in the research and development of new methods for prognostic and classification model training based on advances in the field of artificial intelligence [1, 2, 3]. Metabolomics refers to the systematic study of the unique chemical fingerprints that cellular processes leave behind. The metabolic profile of a person can provide a snapshot of cell physiology and, by extension, metabolomics provide a direct “functional reading of the physiological state” of an organism. Via employing machine learning methodologies, a general evaluation chart of nutritional biomarkers is formulated and an optimised prediction method for body to mass index is investigated with the aim to discover dietary patterns.

Autonomy of differentiation in avian branchial somites and the influence of adjacent tissues

Development ◽  
1987 ◽  
Vol 100 (3) ◽  
pp. 449-462 ◽  
Author(s):  
T. Kenny-Mobbs ◽  
P. Thorogood
Keyword(s):  
Chorioallantoic Membrane ◽  
Growth Conditions ◽  
Explant Culture ◽  
Developmental Pathways ◽  
Morphological Evidence ◽  
Growth Environment ◽  
Enzymatic Dissociation ◽  
Time Migration ◽  
Recombination Experiments ◽  
Do So

This study investigates the differentiative abilities of avian brachial somites at stages of development before, during and after the migration of somitic cells into the wing primordium. These somites are the source of cells that migrate into the forelimbs and there give rise exclusively, and totally, to the skeletal muscle lineage of the wing and yet show no morphological evidence of commitment to that fate when they leave the somites. The aim of the study was to see if the brachial somitic cells are committed to particular developmental pathways at these stages. The brachial somites were isolated from HH stage-12, -15 and -18 chick embryos, either by microdissection or enzymatic dissociation, and grown in organ culture, in explant culture on different substrata or on the chorioallantoic membrane (CAM) of host chicks, either alone or in combination with adjacent tissues. Myogenesis and chondrogenesis occurred in all stage-18 enzymatically separated somites, regardless of the growth environment. Myogenesis was reduced in stage-15 somites and unobservable in stage-12 somites; however, recombination of stage-12 somites with epithelium or neural tube increased the incidence of myogenesis at this stage. The incidence of chondrogenesis was also less in the younger explants. Unlike its effect on myogenic expression, recombination with epithelium resulted in a dramatic decrease in chondrogenesis in both stage-12 and -15 somites. The recombination experiments suggest that conditions that maintain the normal spatial relationships within isolated somites permit expression of a preexisting specification to a particular fate. They also show that the overlying epithelium can inhibit chondrogenesis in these somites. Overall, the results suggest that by the time migration of somitic cells into wing regions is finishing, brachial somitic cells have become stabilized in their ability to undergo both myogenesis and chondrogenesis for they will do so under a variety of growth conditions and independently of adjacent tissues. However, immediately before (stage 12) and shortly after (stage 15) the onset of migration, both myogenic and chondrogenic expression by brachial somitic cells are still under the influence of interactions with adjacent tissues.

NMR methods for in-situ biofilm metabolism studies: spatial and temporal resolved measurements

2005 ◽  
Vol 52 (7) ◽  
pp. 7-12 ◽  
Author(s):  
P.D. Majors ◽  
J.S. McLean ◽  
J.K. Fredrickson ◽  
R.A. Wind
Keyword(s):  
Magnetic Resonance ◽  
Cell Metabolism ◽  
Shewanella Oneidensis ◽  
Growth Conditions ◽  
Magnetic Resonance Images ◽  
Ex Situ ◽  
Adherent Cell ◽  
Growth Environment ◽  
Environment Control

We are developing novel nuclear magnetic resonance (NMR) microscopy, spectroscopy and combined NMR/optical techniques for the study of biofilms under known, controlled growth conditions. Objectives include: time and depth-resolved metabolite concentrations with isotropic spatial resolution on the order of 10 microns, metabolic pathways and flux rates, mass transport and ultimately their correlation with gene expression by optical microscopy in biofilms. We describe the implementation of ex-situ grown biofilms to improve growth environment control and NMR analysis. In-situ NMR depth resolved metabolite profiling techniques are introduced and demonstrated for a Shewanella oneidensis strain MR-1 biofilm. Finally, initial combined confocal fluorescence and magnetic resonance images are shown for a GFP-labeled Shewanella biofilm. These methods are equally applicable to other biofilm systems of interest; thus they may provide a significant contribution toward the understanding of adherent cell metabolism.

scholarly journals Using measures of single‐cell physiology and physiological state to understand organismic aging

Aging Cell ◽  
2015 ◽  
Vol 15 (1) ◽  
pp. 4-13 ◽  
Author(s):  
Alexander Mendenhall ◽  
Monica Driscoll ◽  
Roger Brent
Keyword(s):  
Single Cell ◽  
Physiological State ◽  
Cell Physiology ◽  
Single Cell Physiology

scholarly journals Superoxide dismutase, catalase, and peroxidase in ammonium-grown and nitrogen-fixing Azospirillum brasilense

1984 ◽  
Vol 30 (10) ◽  
pp. 1222-1228 ◽  
Author(s):  
Richard W. Clara ◽  
Roger Knowles
Keyword(s):  
Superoxide Dismutase ◽  
Electron Acceptor ◽  
Azospirillum Brasilense ◽  
Polyacrylamide Gel Electrophoresis ◽  
Growth Conditions ◽  
Sod Activity ◽  
Batch Cultures ◽  
Physiological Conditions ◽  
Azospirillum Brasilense Sp7 ◽  
In Cells

Superoxide dismutase (SOD), catalase (CAT), and peroxidase (PER) activities were studied in ammonium-grown and N2-fixing batch cultures of Azospirillum brasilense Sp7. PER activity, as measured using o-dianisidine or 3,3′-diaminobenzidine as the H donor, was not significant in most growth conditions. SOD activity increased in response to higher O2 concentrations but was also present in cells grown anaerobically with nitrate [Formula: see text] or nitrous oxide (N2O) as electron acceptor. CAT activity increased at lower O2 concentrations and was highest in cells grown anaerobically with [Formula: see text] as electron acceptor. Polyacrylamide gel electrophoresis of cell-free extracts revealed only one band of SOD activity under each of the physiological conditions employed, compared with three for aerobically grown Escherichia coli K12. This band proved to be iron-containing SOD (FeSOD) on the basis of inhibitor sensitivity.

Growth temperature-dependent stearoyl coenzyme A desaturase activity of Fusarium oxysporum microsomes

1978 ◽  
Vol 56 (12) ◽  
pp. 1109-1114 ◽  
Author(s):  
Alan C. Wilson ◽  
Richard W. Miller
Keyword(s):  
Fusarium Oxysporum ◽  
Spectrophotometric Analysis ◽  
Oleic Acid Content ◽  
Temperature Dependent ◽  
Different Temperatures ◽  
Sulfur Protein ◽  
Band Absorption ◽  
Iron Sulfur Protein ◽  
Stearoyl Coa Desaturase ◽  
In Cells

The characteristics of the microsomal stearoyl CoA desaturase (EC 1.14.99.5) of vegetative Fusarium oxysporum cells grown at different temperatures were studied. The enzyme had an unusual preference for NADPH (Km = 38 μM) over NADH (Km = 89 μM) as electron donor, and a relatively high optimum pH of 8.3. Enzyme activity was highest in microsomes from cells grown at 37 °C and lowest in cells grown at 15 °C. This result correlated well with the observed changes in oleic acid content of the microsomal lipids.Both NADPH-linked reductase activities and hemoprotein content were lowest in cells grown at 37 °C. Spectrophotometric analysis of the microsomal hemoproteins indicated the absence of cytochrome b5 and the presence of a b-type heme with a pyridine hemochrome α band absorption maximum at 565 nm. Labile sulfide analysis and inhibitor studies with thenoyltrifluoroacetone suggested a role for an iron–sulfur protein in the electron transfer system associated with the desaturase.

scholarly journals An interpretable flux-based machine learning model of drug interactions across metabolic space and time

2021 ◽  
Author(s):  
Carolina H Chung ◽  
Sriram Chandrasekaran
Keyword(s):  
Machine Learning ◽  
Combination Therapy ◽  
Drug Interactions ◽  
Growth Conditions ◽  
Drug Combinations ◽  
Time Interval ◽  
Therapy Outcomes ◽  
Data Types ◽  
Growth Environment ◽  
Therapy Design

Drug combinations are a promising strategy to counter antibiotic resistance. However, current experimental and computational approaches do not account for the entire complexity involved in combination therapy design, such as the effect of the growth environment, drug order, and time interval. To address these limitations, we present an approach that uses genome-scale metabolic modeling and machine learning to explain and guide combination therapy design. Our approach (a) accommodates diverse data types, (b) accurately predicts drug interactions in various growth conditions, (c) accounts for time- and order-specific interactions, and (d) identifies mechanistic factors driving drug interactions. The entropy in bacterial stress response, time between treatments, and gluconeogenesis activation were the most predictive features of combination therapy outcomes across time scales and growth conditions. Analysis of the vast landscape of condition-specific drug interactions revealed promising new drug combinations and a tradeoff in the efficacy between simultaneous and sequential combination therapies.

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