THE GLUCOSE UPTAKE KINETICS OF SOME MARINE BACTERIA

1966 ◽  
Vol 12 (5) ◽  
pp. 995-1003 ◽  
Author(s):  
R. D. Hamilton ◽  
K. M. Morgan ◽  
J. D. H. Strickland
Keyword(s):  
Glucose Uptake ◽  
Marine Bacteria ◽  
Uptake Kinetics ◽  
Microbial Populations ◽  
Ecological Significance ◽  
Factors Affecting ◽  
Low Concentrations ◽  
Pure Cultures ◽  
Low Levels ◽  
Kinetics Of

The kinetics of glucose uptake by marine microbial populations have been investigated. Pure cultures were used in an attempt to define the conditions affecting uptake kinetics. The use of routine marine microbiological media did not isolate microorganisms capable of responding to the substrate levels that one might expect to find in the ocean, but a chemostat approach was successful in the isolation of such forms. Some factors affecting the uptake of glucose at very low levels were investigated. The kinetic approach with pure cultures has possible application as a bioassay method for substrates in low concentrations in seawater. The ecological significance of the investigation is discussed.

Glucose uptake kinetics of Saccharomyces cerevisiae monitored with a newly developed FIA

1996 ◽  
Vol 50 (1) ◽  
pp. 1-12 ◽  
Author(s):  
S.A. Rothen ◽  
M. Saner ◽  
S. Meenakshisundaram ◽  
B. Sonnleitner ◽  
A. Fiechter
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Glucose Uptake ◽  
Uptake Kinetics ◽  
Kinetics Of

scholarly journals Aging in vitro and D-glucose uptake kinetics of diploid human fibroblasts

1981 ◽  
Vol 106 (1) ◽  
pp. 99-108 ◽  
Author(s):  
T. Cremer ◽  
K. Werdan ◽  
A. F. G. Stevenson ◽  
K. Lehner ◽  
O. Messerschmidt
Keyword(s):  
Glucose Uptake ◽  
Human Fibroblasts ◽  
Uptake Kinetics ◽  
Kinetics Of

scholarly journals Anaerobic Oxidation of Arsenite Linked to Chlorate Reduction

2010 ◽  
Vol 76 (20) ◽  
pp. 6804-6811 ◽  
Author(s):  
Wenjie Sun ◽  
Reyes Sierra-Alvarez ◽  
Lily Milner ◽  
Jim A. Field
Keyword(s):  
Organic Carbon ◽  
16S Rrna ◽  
Molar Ratio ◽  
Gene Clone ◽  
Rrna Gene ◽  
Microbial Oxidation ◽  
Anaerobic Conditions ◽  
Low Concentrations ◽  
Pure Cultures ◽  
Low Levels

ABSTRACT Microorganisms play a significant role in the speciation and mobility of arsenic in the environment. In this study, the oxidation of arsenite [As(III)] to arsenate [As(V)] linked to chlorate (ClO3 −) reduction was shown to be catalyzed by sludge samples, enrichment cultures (ECs), and pure cultures incubated under anaerobic conditions. No activity was observed in treatments lacking inoculum or with heat-killed sludge, or in controls lacking ClO3 −. The As(III) oxidation was linked to the complete reduction of ClO3 − to Cl−, and the molar ratio of As(V) formed to ClO3 − consumed approached the theoretical value of 3:1 assuming the e − equivalents from As(III) were used to completely reduce ClO3 −. In keeping with O2 as a putative intermediate of ClO3 − reduction, the ECs could also oxidize As(III) to As(V) with O2 at low concentrations. Low levels of organic carbon were essential in heterotrophic ECs but not in autotrophic ECs. 16S rRNA gene clone libraries indicated that the ECs were dominated by clones of Rhodocyclaceae (including Dechloromonas, Azospira, and Azonexus phylotypes) and Stenotrophomonas under autotrophic conditions. Additional phylotypes (Alicycliphilus, Agrobacterium, and Pseudoxanthomonas) were identified in heterotrophic ECs. Two isolated autotrophic pure cultures, Dechloromonas sp. strain ECC1-pb1 and Azospira sp. strain ECC1-pb2, were able to grow by linking the oxidation of As(III) to As(V) with the reduction of ClO3 −. The presence of the arsenite oxidase subunit A (aroA) gene was demonstrated with PCR in the ECs and pure cultures. This study demonstrates that ClO3 − is an alternative electron acceptor to support the microbial oxidation of As(III).

Kinetics of Various 99mTc-Sn-Pyrophosphate Compounds in the Rat

1977 ◽  
Vol 16 (04) ◽  
pp. 157-162 ◽  
Author(s):  
C. Schümichen ◽  
B. Mackenbrock ◽  
G. Hoffmann
Keyword(s):  
Normal Saline ◽  
Half Life ◽  
Compound A ◽  
Short Half Life ◽  
Low Concentrations ◽  
The Stability ◽  
Kinetics Of ◽  
In Vitro Stability

SummaryThe bone-seeking 99mTc-Sn-pyrophosphate compound (compound A) was diluted both in vitro and in vivo and proved to be unstable both in vitro and in vivo. However, stability was much better in vivo than in vitro and thus the in vitro stability of compound A after dilution in various mediums could be followed up by a consecutive evaluation of the in vivo distribution in the rat. After dilution in neutral normal saline compound A is metastable and after a short half-life it is transformed into the other 99mTc-Sn-pyrophosphate compound A is metastable and after a short half-life in bone but in the kidneys. After dilution in normal saline of low pH and in buffering solutions the stability of compound A is increased. In human plasma compound A is relatively stable but not in plasma water. When compound B is formed in a buffering solution, uptake in the kidneys and excretion in urine is lowered and blood concentration increased.It is assumed that the association of protons to compound A will increase its stability at low concentrations while that to compound B will lead to a strong protein bond in plasma. It is concluded that compound A will not be stable in vivo because of a lack of stability in the extravascular space, and that the protein bond in plasma will be a measure of its in vivo stability.

Arsenic removal by MF membrane with chemical sludge adsorption and NF membrane equipped with vibratory shear enhanced process

2003 ◽  
Vol 3 (5-6) ◽  
pp. 303-310 ◽  
Author(s):  
S.-H. Yi ◽  
S. Ahmed ◽  
Y. Watanabe ◽  
K. Watari
Keyword(s):  
Arsenic Removal ◽  
Membrane Surface ◽  
Membrane Process ◽  
Low Concentrations ◽  
Strong Shear ◽  
Low Levels ◽  
Removal Processes ◽  
Removal Of Arsenic ◽  
Concentration Polarization Layer ◽  
Chemical Sludge

Conventional arsenic removal processes have difficulty removing low concentrations of arsenic ion from water. Therefore, it is very hard to comply with stringent low levels of arsenic, such as below 10 μg/L. So, we have developed two arsenic removal processes which are able to comply with more stringent arsenic regulations. They are the MF membrane process combined with chemical sludge adsorption and NF membrane process equipped with the vibratory shear enhanced process (VSEP). In this paper, we examine the performance of these new processes for the removal of arsenic ion of a low concentration from water. We found that chemical sludge produced in the conventional rapid sand filtration plants can effectively remove As (V) ions of H2AsO4- and HAsO42- through anion exchange reaction. The removal efficiency of MF membrane process combined with chemical sludge adsorption increased to about 36%, compared to MF membrane alone. The strong shear force on the NF membrane surface produced by vibration on the VSEP causes the concentration polarization layer to thin through increased back transport velocity of particles. So, it can remove even dissolved constituents effectively. Therefore, As (V) ions such as H2AsO4- and HAsO42- can be removed. The concentration of As (V) ions decreased from 50 μg/L to below 10 μg/L and condensation factor in recirculating water increased up to 7 times by using NF membrane equipped with VSEP.

Submerged upflow biotower operation and computer simulation

1994 ◽  
Vol 30 (11) ◽  
pp. 143-146
Author(s):  
Ronald D. Neufeld ◽  
Christopher A. Badali ◽  
Dennis Powers ◽  
Christopher Carson
Keyword(s):  
Computer Simulation ◽  
Benzoic Acid ◽  
Computer Model ◽  
Rate Constants ◽  
Batch Mode ◽  
Operational Conditions ◽  
First Order ◽  
Low Concentrations ◽  
Biological Transformation ◽  
Kinetics Of

A two step operation is proposed for the biodegradation of low concentrations (< 10 mg/L) of BETX substances in an up flow submerged biotower configuration. Step 1 involves growth of a lush biofilm using benzoic acid in a batch mode. Step 2 involves a longer term biological transformation of BETX. Kinetics of biotransformations are modeled using first order assumptions, with rate constants being a function of benzoic acid dosages used in Step 1. A calibrated computer model is developed and presented to predict the degree of transformation and biomass level throughout the tower under a variety of inlet and design operational conditions.

Study of nickel-molybdenum catalysts for methanation of carbon monoxide

1980 ◽  
Vol 45 (3) ◽  
pp. 783-790 ◽  
Author(s):  
Petr Taras ◽  
Milan Pospíšil
Keyword(s):  
Carbon Monoxide ◽  
Catalytic Activity ◽  
Mixed Oxides ◽  
Minor Component ◽  
Fast Neutrons ◽  
Scanning Calorimetry ◽  
Low Concentrations ◽  
Γ Rays ◽  
Molybdenum Catalysts ◽  
Kinetics Of

Catalytic activity of nickel-molybdenum catalysts for methanation of carbon monoxide and hydrogen was studied by means of differential scanning calorimetry. The activity of NiMoOx systems exceeds that of carrier-free nickel if x < 2, and is conditioned by the oxidation degree of molybdenum, changing in dependence on the composition in the region Mo-MoO2. The activity of the catalysts is adversely affected by irradiation by fast neutrons, dose 28.1 Gy, or by γ rays using doses in the region 0.8-52 kGy. The system is most susceptible to irradiation in the region of low concentrations of the minor component (about 1 mol.%). The dependence of changes in catalytic activity of γ-irradiated samples on the dose exhibits a maximum in the range of 2-5 kGy. The changes in catalytic activity are stimulated by the change of reactivity of the starting mixed oxides, leading to different kinetics of their reduction and modification of their adsorption properties. The irradiation of the catalysts results in lowered concentration of the active centres for the methanation reaction.

scholarly journals Co-Occurrence of Regulated and Emerging Mycotoxins in Corn Silage: Relationships with Fermentation Quality and Bacterial Communities

Toxins ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 232
Author(s):  
Antonio Gallo ◽  
Francesca Ghilardelli ◽  
Alberto Stanislao Atzori ◽  
Severino Zara ◽  
Barbara Novak ◽  
...  
Keyword(s):  
Bacterial Community ◽  
Bacterial Communities ◽  
Dry Matter ◽  
Kojic Acid ◽  
Corn Silage ◽  
Fungal Metabolites ◽  
Fusarium Mycotoxins ◽  
Low Concentrations ◽  
Fermentation Quality ◽  
Low Levels

Sixty-four corn silages were characterized for chemicals, bacterial community, and concentrations of several fungal metabolites. Silages were grouped in five clusters, based on detected mycotoxins, and they were characterized for being contaminated by (1) low levels of Aspergillus- and Penicillium-mycotoxins; (2) low levels of fumonisins and other Fusarium-mycotoxins; (3) high levels of Aspergillus-mycotoxins; (4) high levels of non-regulated Fusarium-mycotoxins; (5) high levels of fumonisins and their metabolites. Altersetin was detected in clusters 1, 3, and 5. Rugulusovin or brevianamide F were detected in several samples, with the highest concentration in cluster 3. Emodin was detected in more than 50.0% of samples of clusters 1, 3 and 5, respectively. Kojic acid occurred mainly in clusters 1 and 2 at very low concentrations. Regarding Fusarium mycotoxins, high occurrences were observed for FB3, FB4, FA1, whereas the average concentrations of FB6 and FA2 were lower than 12.4 µg/kg dry matter. Emerging Fusarium-produced mycotoxins, such as siccanol, moniliformin, equisetin, epiequisetin and bikaverin were detected in the majority of analyzed corn silages. Pestalotin, oxaline, phenopirrozin and questiomycin A were detected at high incidences. Concluding, this work highlighted that corn silages could be contaminated by a high number of regulated and emerging mycotoxins.

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