scholarly journals Metabolt: An In-Situ Instrument to Characterize the Metabolic Activity of Microbial Soil Ecosystems Using Electrochemical and Gaseous Signatures

Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4479
Author(s):  
Miracle Israel Nazarious ◽  
María-Paz Zorzano ◽  
Javier Martín-Torres
Keyword(s):  
Thermal Stress ◽  
Osmotic Stress ◽  
Metabolic Activity ◽  
Atmospheric Chemistry ◽  
Metabolic Response ◽  
Pure Water ◽  
Soil Microbiome ◽  
Laboratory Research ◽  
Gaseous Species ◽  
Space Applications

Metabolt is a portable soil incubator to characterize the metabolic activity of microbial ecosystems in soils. It measures the electrical conductivity, the redox potential, and the concentration of certain metabolism-related gases in the headspace just above a given sample of regolith. In its current design, the overall weight of Metabolt, including the soils (250 g), is 1.9 kg with a maximum power consumption of 1.5 W. Metabolt has been designed to monitor the activity of the soil microbiome for Earth and space applications. In particular, it can be used to monitor the health of soils, the atmospheric-regolith fixation, and release of gaseous species such as N2, H2O, CO2, O2, N2O, NH3, etc., that affect the Earth climate and atmospheric chemistry. It may be used to detect and monitor life signatures in soils, treated or untreated, as well as in controlled environments like greenhouse facilities in space, laboratory research environments like anaerobic chambers, or simulating facilities with different atmospheres and pressures. To illustrate its operation, we tested the instrument with sub-arctic soil samples at Earth environmental conditions under three different conditions: (i) no treatment (unperturbed); (ii) sterilized soil: after heating at 125 °C for 35.4 h (thermal stress); (iii) stressed soil: after adding 25% CaCl2 brine (osmotic stress); with and without addition of 0.5% glucose solution (for control). All the samples showed some distinguishable metabolic response, however there was a time delay on its appearance which depends on the treatment applied to the samples: 80 h for thermal stress without glucose, 59 h with glucose; 36 h for osmotic stress with glucose and no significant reactivation in the pure water case. This instrument shows that, over time, there is a clear observable footprint of the electrochemical signatures in the redox profile which is complementary to the gaseous footprint of the metabolic activity through respiration.

scholarly journals Microbiology and atmospheric processes: chemical interactions of primary biological aerosols

2008 ◽  
Vol 5 (4) ◽  
pp. 1073-1084 ◽  
Author(s):  
L. Deguillaume ◽  
M. Leriche ◽  
P. Amato ◽  
P. A. Ariya ◽  
A.-M. Delort ◽  
...  
Keyword(s):  
Metabolic Activity ◽  
Atmospheric Chemistry ◽  
Ph Value ◽  
Chemical Constituents ◽  
Fungal Spores ◽  
Chemical Properties ◽  
Nutrient Concentrations ◽  
Chemical Interactions ◽  
Biological Aerosols ◽  
Micro Organisms

Abstract. This paper discusses the influence of primary biological aerosols (PBA) on atmospheric chemistry and vice versa through microbiological and chemical properties and processes. Several studies have shown that PBA represent a significant fraction of air particulate matter and hence affect the microstructure and water uptake of aerosol particles. Moreover, airborne micro-organisms, namely fungal spores and bacteria, can transform chemical constituents of the atmosphere by metabolic activity. Recent studies have emphasized the viability of bacteria and metabolic degradation of organic substances in cloud water. On the other hand, the viability and metabolic activity of airborne micro-organisms depend strongly on physical and chemical atmospheric parameters such as temperature, pressure, radiation, pH value and nutrient concentrations. In spite of recent advances, however, our knowledge of the microbiological and chemical interactions of PBA in the atmosphere is rather limited. Further targeted investigations combining laboratory experiments, field measurements, and modelling studies will be required to characterize the chemical feedbacks, microbiological activities at the air/snow/water interface supplied to the atmosphere.

Differential metabolic activity by dental plaque bacteria in association with two preparations of MUC5B mucins in solution and in biofilms

Microbiology ◽  
2009 ◽  
Vol 155 (1) ◽  
pp. 53-60 ◽  
Author(s):  
Claes Wickström ◽  
Ian R. Hamilton ◽  
Gunnel Svensäter
Keyword(s):  
Biological Activity ◽  
Metabolic Activity ◽  
Dental Plaque ◽  
Metabolic Response ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Biological Properties ◽  
Model Surface ◽  
Tetrazolium Chloride ◽  
Salivary Mucin

Salivary mucin, MUC5B, is an oligomeric glycoprotein, heterogeneous in size and with a diverse repertoire of oligosaccharides, which differ in composition and charge. Since complex salivary glycoproteins are considered to be the major source of nutrients for the oral supragingival microbiota, the major aim of the current study was to determine whether different preparations of non-denatured MUC5B could be isolated exhibiting different biological properties in relation to the microflora associated with the surfaces of the oral cavity. Two preparations, solMUC5B and gelMUC5B, were isolated by density-gradient centrifugation and were shown to have different buoyant densities, carbohydrate content and surface-adsorbing characteristics. To ascertain differences in biological activity, the two mucin preparations, both in solution and adsorbed to a model surface, were incubated with freshly isolated dental plaque and assayed for metabolic (dehydrogenase) activity with the fluoresecent substrate CTC (5-cyano-2,3-ditolyl tetrazolium chloride). The plaque bacteria exhibited higher metabolism with the solMUC5B preparation in solution, with 79.4 % active plaque cells compared to the controls without mucin (9.6 %), while gelMUC5B showed 48.2 % active cells with the same plaque population. In contrast, the same mucins adhered to a surface elicited a significantly lower metabolic response, with surface-associated plaque cells showing only 12.1 % active cells with solMUC5B and 29.2 % with gelMUC5B. These results suggested that the metabolism by the plaque cells adsorbed to surface-associated mucins was downregulated compared to the same cells suspended in mucin solution. This was confirmed in an experiment where active dispersed plaque/solMUC5B suspensions were shown to lose significant metabolic activity (e.g. 74.9 to 19.3 %) when allowed to interact with gelMUC5B adsorbed to a surface. Clearly, the solMUC5B and gelMUC5B preparations exhibited different biological activity when assayed with freshly plaque bacteria in suspension and in a biofilm.

Influence of osmotic stress on upper lethal temperatures in the cyprinodontid fish Fundulus heteroclitus (L.)

1972 ◽  
Vol 50 (6) ◽  
pp. 787-791 ◽  
Author(s):  
E. T. Garside ◽  
Z. K. Chin-Yuen-Kee
Keyword(s):  
Thermal Stress ◽  
Osmotic Stress ◽  
Fresh Water ◽  
Thermal Tolerance ◽  
Fundulus Heteroclitus ◽  
Thermal Acclimation ◽  
Lethal Temperature ◽  
Lethal Temperatures

Upper lethal temperatures determined for the mummichog Fundulus heteroclitus (L.) for exposures of 10 000 min ranged from 18.58C to 36.31C. Osmotic acclimations were prepared at 0, 14, and 32‰ salinity (S), at thermal acclimations of 5 and 15C, and at 14 and 32‰ S at 25C. Mummichog could not survive in the acclimatory combination of 0‰ S at 25C. Subsamples from these acclimatory combinations were exposed to thermal stress at 0, 14, and 32‰ S. Highest upper lethal temperatures were observed in isosmotic test salinity (14‰). Intermediate lethal levels occurred in seawater (32‰ S) and the lowest lethal temperatures occurred in fresh water (0‰ S). Upper lethal temperature increased with increasing thermal acclimation but generally, prior osmotic experience did not modify thermal tolerance. There was no relation between order of death and size in 18 of the 24 test combinations. In the remaining six, the largest members died first in four and the smallest died first in two test combinations.

Metabolic response of the cannonball jellyfish Stomolophus meleagris upon short-term exposure to thermal stress

2020 ◽  
Vol 166 ◽  
pp. 101959
Author(s):  
C.A. Nevarez-Lopez ◽  
A. Sanchez-Paz ◽  
J. Lopez-Martinez ◽  
R. Llera-Herrera ◽  
A. Muhlia-Almazan
Keyword(s):  
Thermal Stress ◽  
Metabolic Response ◽  
Short Term ◽  
Short Term Exposure ◽  
Stomolophus Meleagris

Fetal Central Auditory System Metabolic Response to Cochlear Implant Stimulation

2002 ◽  
Vol 127 (3) ◽  
pp. 131-137 ◽  
Author(s):  
Patrick J. Antonelli ◽  
Kenneth J. Gerhardt ◽  
Robert M. Abrams ◽  
Xinyan Huang
Keyword(s):  
Auditory System ◽  
Metabolic Activity ◽  
Glucose Utilization ◽  
Metabolic Response ◽  
Auditory Brainstem ◽  
Central Auditory System ◽  
Electrode Arrays ◽  
Fetal Sheep ◽  
Brainstem Response ◽  
Normal Controls

OBJECTIVES: The purpose of this study was to examine the effects of profound auditory deprivation and its treatment by cochlear implantation and stimulation on the metabolic activity of the central auditory system in fetal sheep. METHODS: Six ovine fetuses at 85% to 90% gestation were bilaterally deafened by kanamycin perfusion and unilaterally implanted with cochlear electrode arrays. Half of the implanted animals were stimulated with an extrauterine sound processor, and half were not. Four animals served as hearing controls. One week postoperatively, central nervous system metabolic activity was evaluated in ambient laboratory noise by quantitative autoradiography using 14C-deoxyglucose. RESULTS: Kanamycin perfusion deafened all treated animals as verified by auditory brainstem response and scanning electron microscopy. Glucose utilization in the inferior colliculus was markedly lower in deafened and unstimulated animals relative to hearing controls. Glucose utilization in implanted-stimulated animals was similar to normal controls. CONCLUSIONS: Changes in central auditory system metabolic activity associated with congenital deafness may be minimized by prompt auditory habilitation.

Recovery of Chondrocyte Metabolic Activity after Thermal Exposure

2003 ◽  
Vol 31 (3) ◽  
pp. 392-398 ◽  
Author(s):  
Lee D. Kaplan ◽  
Constance R. Chu ◽  
James P. Bradley ◽  
Freddie H. Fu ◽  
Rebecca K. Studer
Keyword(s):  
Thermal Stress ◽  
Articular Cartilage ◽  
Metabolic Activity ◽  
Clinical Relevance ◽  
Thermal Exposure ◽  
Radiofrequency Energy ◽  
Human Cartilage ◽  
Energy Devices ◽  
Increased Sensitivity ◽  
Thermal Chondroplasty

Background The relationship between temperature elevation and thermal exposure time during thermal chondroplasty has implications for cell viability and subsequent articular cartilage function. Purpose To characterize cartilage metabolic changes after exposure to thermal stress and to determine whether changes seen acutely are reversible. Study Design Controlled laboratory study. Methods Human cartilage was exposed to a 45°, 50°, or 55°C bath for up to 3 minutes. Untreated control specimens were analyzed with each group. Viability and metabolic capability of treated and untreated specimens were evaluated immediately or 1 week after thermal stress by using methylthiotetrazole conversion, 3H-serine incorporation into protein, and 35S-sulfate incorporation into newly synthesized proteoglycan. Results Nonarthritic and arthritic articular cartilage metabolic activity declined with increasing thermal exposure. Articular cartilage displayed a recovery from thermal stress after exposure to the 50°C but not the 55°C bath. Arthritic cartilage displayed increased sensitivity with higher temperatures. Conclusions Understanding of the increased sensitivity to thermal stress of arthritic articular cartilage may be helpful in thermally based treatments. Clinical Relevance Further correlation with the temperatures attained during thermal chondroplasty will be necessary to confirm the clinical relevance of these in vitro observations to the use of radiofrequency energy devices to treat partial-thickness chondral lesions.

Metabolic Imaging Predicts Response, Survival, and Recurrence in Adenocarcinomas of the Esophagogastric Junction

2006 ◽  
Vol 24 (29) ◽  
pp. 4692-4698 ◽  
Author(s):  
Katja Ott ◽  
Wolfgang A. Weber ◽  
Florian Lordick ◽  
Karen Becker ◽  
Raymonde Busch ◽  
...  
Keyword(s):  
Survival Rate ◽  
Metabolic Activity ◽  
Esophagogastric Junction ◽  
Response Rate ◽  
Metabolic Response ◽  
Locally Advanced ◽  
Metabolic Imaging ◽  
Preoperative Treatment ◽  
Histopathologic Response ◽  
Tumor Stages

PurposeA previous study suggested that measurement of therapy-induced changes in tumor glucose metabolism by positron emission tomography (PET) with the glucose analog [18F]fluorodeoxyglucose (FDG) allows to select patients most likely to benefit from preoperative chemotherapy in adenocarcinomas of the esophagogastric junction (AEG). The aim of this study was to prospectively validate these findings by using an a priori definition of metabolic response.Patients and MethodsSixty-five patients with locally advanced AEGs were included. Tumor glucose utilization was quantitatively assessed by FDG-PET before chemotherapy and 14 days after initiation of therapy. Patients were classified as metabolic responders when the metabolic activity of the primary tumor had decreased by more than 35% at the time of the second PET.ResultsMetabolic responders showed a high histopathologic response rate (44%) with a 3-year survival rate of 70%. In contrast, prognosis was poor for metabolic nonresponders with a histopathologic response rate of 5% (P = .001) and a 3-year survival rate of 35% (P = .01). A multivariate analysis (covariates: ypT-, ypN-category, histopathologic response) demonstrated that metabolic response was the only factor predicting recurrence (P = .018) in the subgroup of completely resected (R0) patients.ConclusionThis study prospectively demonstrates that changes in tumor metabolic activity during chemotherapy predict response, prognosis, and recurrence. These data provide the basis for clinical trials in which preoperative treatment is changed for patients without a metabolic response early in the course of therapy. PET-guided induction therapy may even be applicable to earlier tumor stages because surgery is only minimally delayed in nonresponding patients.

scholarly journals THE CORRELATION OF A BIPHASIC METABOLIC RESPONSE WITH A BIPHASIC RESPONSE IN RESISTANCE TO TUBERCULOSIS IN RABBITS

1962 ◽  
Vol 115 (5) ◽  
pp. 881-890 ◽  
Author(s):  
Marvin J. Allison ◽  
Peter Zappasodi ◽  
Max B. Lurie
Keyword(s):  
Metabolic Activity ◽  
Metabolic Response ◽  
Mononuclear Phagocytes ◽  
Protein Therapy ◽  
Biphasic Response ◽  
Bcg Vaccination ◽  
Second Stage ◽  
Resistance To Infection ◽  
Metabolic Activities

We have found a phase of susceptibility associated with a reduced metabolic activity on the part of peritoneal mononuclear phagocytes taken from BCG-vaccinated rabbits. A second stage of heightened resistance to infection was found to be associated with a heightened metabolic activity. The period of susceptibility in BCG vaccination is primarily concerned with initiation of the infection and not with the progression of the disease, which in both stages is increased. These reactions are discussed in relation to other conditions, such as nonspecific protein therapy and the administration of endotoxin, which also have similiar biphasic stages of resistance. Of incidental interest is the fact that rabbits who received 400 roentgen units are two years later still unable to respond to BCG vaccination with an increase in resistance. We conclude that there is a relationship between the level of certain metabolic activities of reticuloendothelial cells and resistance to tuberculosis.

scholarly journals Microbial Loop Dynamics in Antarctic Sea-Ice

2021 ◽  
Author(s):  
◽  
Andrew Robert Martin
Keyword(s):  
Sea Ice ◽  
Community Composition ◽  
Metabolic Activity ◽  
Bacterial Growth ◽  
Metabolic Response ◽  
Microbial Loop ◽  
Microbial Dynamics ◽  
Antarctic Sea Ice

<p>Sea-ice is a predominant feature of polar oceans and exerts a unique influence on marine ecosystems. The annual circumpolar expansion of sea-ice around Antarctica provides a stable platform for the in situ colonisation and growth of a diverse assemblage of microbes that are integral to the energy base of the Southern Ocean. An active microbial loop has been proposed to operate within the ice matrix connecting bacteria, microalgae and protozoa, but validating this metabolic pathway has historically relied on bulk correlations of chlorophyll a (a surrogate for microalgal biomass) and estimates of bacterial production or abundance. I investigate the microbial loop using a range of physiological, genetic, and ecological techniques to determine whether the photosynthate exuded by phototrophic microalgae serves as a growth substrate for heterotrophic bacteria. This link is examined at a range of spatial (in vitro and in situ experiments) and temporal (8 hours to 18 days) scales by manipulating the supply of algal-derived photosynthate and documenting the subsequent change in bacterial metabolic activity, cell abundance and community composition. Single-cell analysis of both bacterial membrane integrity and intracellular activity revealed that sea ice is among the most productive microbial habitats. In short-term in vitro experiments, increased availability of dissolved organic matter (DOM) was shown to elicit a rapid metabolic response in sea ice bacteria, however single-activity was significantly reduced in treatments where photosynthate was restricted by either removing the majority of algal cells or inhibiting photosynthesis with 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU). To verify this metabolic response, microcosm simulations were conducted over a period of 9 days with microbes derived from two regions of the ice (bottom layer and high-salinity surface region) with presumed differences in the concentration of DOM. Metabolic activity was relatively low in bacteria derived from the high-saline region of the ice and in cultures spiked with DCMU, photosynthate limitation restricted bacterial growth and significantly influenced community structure. In contrast, the bottom of the ice is characterised by a high concentration of DOM and bacterial metabolic activity was shown to be higher and DCMU was less influential with respect to changes in bacterial abundance or community composition. To examine in situ microbial dynamics, a series of cores were extracted from Antarctic sea-ice and reinserted into the ice matrix upside down to expose resident microbial assemblages to a significantly different light, temperature and salinity regime. Limited assimilation of algal-derived DOM by bacteria in ice cores that were flipped illustrated a malfunction in the microbial loop after a period of 18 days. Bacteria originally at the bottom of the sea ice appeared to be temperature-limited, while a lack of growth in cells originally at the top of the ice profile was attributed to a community dominated by slow-growing psychrophilic species. A stronger physiological response to disturbance was elicited by microalgae and significant growth was contrasted with severe bleaching and cell death. This reciprocal transplant is the first of its kind to examine the in situ sea ice community and illustrats that although microbial assemblages are similar with respect to trophic dynamics, they are also attuned to distinct regions within the ice. The bacterial assimilation of algal-derived DOM is of fundamental importance to the microbial loop and by confirming that photosynthate is a major stimulus for bacterial growth, these results provide a new and unique insight into microbial dynamics in Antarctic sea-ice.</p>

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