scholarly journals Microbial growth on C1 compounds. Uptake of [14C]formaldehyde and [14C]formate by methane-grown Pseudomonas methanica and determination of the hexose labelling pattern after brief incubation with [14C]methanol

1967 ◽  
Vol 102 (1) ◽  
pp. 94-102 ◽  
Author(s):  
MB Kemp ◽  
JR Quayle
Keyword(s):  
Microbial Growth ◽  
Labelling Pattern

Evaluation of Analytical Methods for Determination of Biogenic Amines in Fresh and Processed Meat

1983 ◽  
Vol 46 (12) ◽  
pp. 1044-1049 ◽  
Author(s):  
J. A. ZEE ◽  
R. E. SIMARD ◽  
L. L'HEUREUX
Keyword(s):  
Biogenic Amines ◽  
Microbial Growth ◽  
Extraction Efficiency ◽  
Meat Products ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Processed Meat ◽  
Fresh Meat ◽  
Microbial Growth Inhibition

Fifteen biogenic amines were separated and quantitated by an automated ion-exchange chromatography technique. Extraction efficiencies for amines from fresh and processed meat using trichloroacetic acid (TCA), perchloric acid and methanol were compared. In general, biogenic amines in meat and meat products were better extracted by TCA. Aliphatic amines were more efficiently extracted than aromatic amines. Type of meat and adsorption of amines on proteins probably affected the extraction efficiency. Both fresh and processed meat products contained high amounts of adrenaline, spermidine and spermine (up to 581, 280 and 685 mg/kg, respectively), but low amounts (13 to 19 mg/kg) of noradrenaline, putrescine, histamine, cadaverine and tyramine. Processed meat contained less amines than fresh meat, suggesting losses during salting and curing or microbial growth inhibition.

Determination of rumen microbial growth in vitro from32P-labelled phosphate incorporation

1977 ◽  
Vol 38 (1) ◽  
pp. 101-114 ◽  
Author(s):  
C. J. Van Nevel ◽  
D. I. Demeyer
Keyword(s):  
Microbial Growth ◽  
Specific Activity ◽  
Rumen Fluid ◽  
List Type ◽  
Substrate Protein ◽  
Isotope Method ◽  
Total Growth ◽  
N Incorporation

1.The extracellular phosphate pool in incubations of rumen fluid or washed cell suspensions of mixed rumen bacteria (WCS) was labelled with32P. From the constant extracellular phosphate pool specific activity and the amount of radioactivity incorporated during incubation, the amount of P incorporated in the microbial fraction was calculated. From the value for nitrogen: P determined in microbial matter, the amount of N incorporated was calculated as a measure of microbial growth.2.Incorporation of soluble non-protein-N in incubations devoid of substrate protein was 50 and 80 % of the values obtained using the isotope method for rumen fluid and WCS respectively. It is suggested that results obtained using the former method reflect 'net growth' of micro-organisms which is the result of simultaneous growth and degradation. The isotope method measures 'total growth', as isotope incorporation is not affected by degradation of non-growing cells.3.Incorporation of32P in P-containing microbial components (mainly nucleic acids) was compared with net synthesis of these components in incubations of WCS. The results showed different specific rates of synthesis and degradation for all components studied. It is concluded that the composition of microbial matter changed during growth.4.When N incorporation, calculated from results obtained using the isotope method in incubations with rumen fluid, was compared with the amount of carbohydrate substrate fermented and the type of fermentation, values between 18.3 and 44.6 g N incorporated/kg of organic matter fermented were obtained. Low values were associated with large proportions of the substrate being fermented to lactate and the use of glucose instead of disaccharides as substrate. Part of the variation could also be attributed to differences in incubation period, reflected in different proportions of polysaccharide formed.5.The use of isotopes for determination of rumen microbial growth in vitro is critically discussed.

Determination of Reduce of Arsenic (III) Toxicity to Pseudomonas fluorescens Using Iron by Combined Methods

2012 ◽  
Vol 599 ◽  
pp. 40-43
Author(s):  
Fei Wang ◽  
Jun Yao ◽  
Hui Lun Chen
Keyword(s):  
Growth Rate ◽  
Heat Flow ◽  
Ir Spectra ◽  
Thermodynamic Parameters ◽  
Microbial Growth ◽  
Heat Evolution ◽  
Growth Rate Constant ◽  
Ft Ir ◽  
Inhibitory Ratio

A series of microcalorimetric experiments were performed to evaluate the As(III), Fe(II), P and their joint effects by analyzing the thermodynamic parameters, microbial growth rate constant k, total heat evolution QT, inhibitory ratio I and highest heat flow Pmax. They were obtained from power-time curves of the growth of P. fluorescens. The effect of mixed As(III), Fe(II) and P were moderate, compared with control, single As(III) or Fe(II). In addition, FT-IR spectra of dry P. fluorescens after the adsoption of As(III) and Fe(II) and their mixture showed that Fe influenced the C-H bonds of the functional groups on the cellwall, the As(III) caused litter effect.

scholarly journals Use of the Microbial Growth Curve in Postantibiotic Effect Studies of Legionella pneumophila

2003 ◽  
Vol 47 (3) ◽  
pp. 1081-1087 ◽  
Author(s):  
Raymond P. Smith ◽  
Aldona L. Baltch ◽  
Phyllis B. Michelsen ◽  
William J. Ritz ◽  
Richard Alteri
Keyword(s):  
Minimum Inhibitory Concentration ◽  
Bacterial Growth ◽  
Legionella Pneumophila ◽  
Microbial Growth ◽  
Inhibitory Concentration ◽  
Growth Curves ◽  
Laboratory Medicine ◽  
Postantibiotic Effect ◽  
Antibiotic Concentration

ABSTRACT Using the standard Craig and Gudmundsson method (W. A. Craig and S. Gudmundsson, p. 296-329, in V. Lorian, ed., Antibiotics in Laboratory Medicine, 1996) as a guideline for determination of postantibiotic effects (PAE), we studied a large series of growth curves for two strains of Legionella pneumophila. We found that the intensity of the PAE was best determined by using a statistically fitted line over hours 3 to 9 following antibiotic removal. We further determined the PAE duration by using a series of observations of the assay interval from hours 3 to 24. We determined that inoculum reduction was not necessarily the only predictor of the PAE but that the PAE was subject to the type and dose of the drug used in the study. In addition, there was a variation between strains. Only levofloxacin at five and ten times the minimum inhibitory concentration (MIC) resulted in a PAE duration of 4 to 10 h for both strains of L. pneumophila tested. Ciprofloxacin at five and ten times the MIC and azithromycin at ten times the MIC caused a PAE for one strain only. No PAE could be demonstrated for either strain with erythromycin or doxycycline. Using the presently described method of measuring PAE for L. pneumophila, we were able to detect differences in PAE which were dependent upon the L. pneumophila strain, the antibiotic tested, and the antibiotic concentration. We suggest the use of mathematically fitted curves for comparison of bacterial growth in order to measure PAE for L. pneumophila.

Determination of nitrogen degradability of some different protein sources by in situ techniques

1999 ◽  
Vol 1999 ◽  
pp. 92-92
Author(s):  
M. Gorgulu ◽  
L. Baykal ◽  
H.R. Kutlu ◽  
C. Atasoglu
Keyword(s):  
Amino Acids ◽  
Small Intestine ◽  
Protein Degradation ◽  
Microbial Growth ◽  
Rumen Fermentation ◽  
Protein Sources ◽  
In Situ Techniques ◽  
The World

The rate and extent of protein degradation in the rumen is very crucial, as it determines the availability of nitrogen to microorganisms and amino acids in the small intestine to the host animals. The protein consumed by the animal should be partly degradable in the rumen, as peptides and amino acids derived from proteolysis are thought to stimulate microbial growth and rumen fermentation under certain conditions. It is, therefore, very important to determine the degradability of different feed ingredients which are grown and used in different regions of the world. The present study was undertaken to assess the degradation characteristics of different protein sources grown and used in Turkey.

scholarly journals A New Sensitive Bioassay for Determination of Microbially Available Phosphorus in Water

1999 ◽  
Vol 65 (5) ◽  
pp. 2032-2034 ◽  
Author(s):  
Markku J. Lehtola ◽  
Ilkka T. Miettinen ◽  
Terttu Vartiainen ◽  
Pertti J. Martikainen
Keyword(s):  
Water Sample ◽  
Energy Supply ◽  
Microbial Growth ◽  
Maximum Growth ◽  
Phosphorus Concentration ◽  
Available Phosphorus ◽  
Assimilable Organic Carbon ◽  
Drinking Waters ◽  
Sensitive Method

ABSTRACT The content of assimilable organic carbon has been proposed to control the growth of microbes in drinking water. However, recent results have shown that there are regions where it is predominantly phosphorus which determines the extent of microbial growth in drinking waters. Even a very low concentration of phosphorus (below 1 μg of P liter−1) can promote extensive microbial growth. We present here a new sensitive method to determine microbially available phosphorus concentrations in water down to 0.08 μg of P liter−1. The method is a bioassay in which the analysis of phosphorus in a water sample is based on maximum growth ofPseudomonas fluorescens P17 when the energy supply and inorganic nutrients, with the exception of phosphorus, do not limit bacterial growth. Maximum growth (CFU) in the water sample is related to the concentration of phosphorus with the factor 373,200 ± 9,400 CFU/μg of PO4-P. A linear relationship was found between cell growth and phosphorus concentration between 0.05 to 10 μg of PO4-P liter−1. The content of microbially available phosphorus in Finnish drinking waters varied from 0.1 to 10.2 μg of P liter−1 (median, 0.60 μg of P liter−1).

scholarly journals Automated Screening Method for Determining Optimum Preservative Systems for Personal and Home Care Products

1998 ◽  
Vol 81 (3) ◽  
pp. 534-539 ◽  
Author(s):  
Melissa E Lenczewski ◽  
Lafonna L Kananen
Keyword(s):  
Home Care ◽  
Microbial Growth ◽  
Screening Method ◽  
Microtiter Plate ◽  
Time Interval ◽  
Association Method ◽  
Test Materials ◽  
Automated Screening ◽  
Recommended Level

abstract A procedure was designed to determine the minimum preservative level (MPL) for personal and home care products. A highly preserved sample and an unpreserved sample were combined at different concentrations within a 96-we 11 microtiter plate by using an autodilutor. A unique tip design made it possible to accurately deliver viscous test materials that cannot be dispensed using vacuumor fluid-filled systems. After inoculation, the sample was evaluated at a specified time interval for the presence of surviving bacteria, yeast, and mold. The lowest concentration of preservative with no microbial growth is the recommended level of preservative for the product. Because sample turbidity may interfere with determination of the endpoint, a colorimetric endpoint was used to indicate growth of microorganisms and to differentiate product from growth. The predicted levels were tested with a modified Cosmetic, Toiletry, and Fragrance Association method. The method successfully predicted effective preservative levels in many personal and home care products with a broad range of viscosities.

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