Factors influencing tartrate uptake by Penicillium charlesii

1968 ◽  
Vol 14 (5) ◽  
pp. 579-585 ◽  
Author(s):  
K. P. Klatt ◽  
J. E. Gander
Keyword(s):  
Spore Germination ◽  
Glucose Concentration ◽  
Factors Influencing ◽  
High Concentrations

The uptake of tartrate by P. charlesii has been studied for cultures that were either aerated by shaking or were kept stationary. Stationary cultures were permeable to tartrate when high concentrations of NH4+ (above 36 mM) and glucose (278 mM) were present. Manganous ion (10−5 M) was required for the uptake of tartrate by stationary cultures containing high concentrations of NH4+. Both stationary and shake cultures were able to remove tartrate from the medium when the glucose concentration was reduced below 278 mM; the process was then no longer dependent upon the presence of Mn2+. The influence of changes in the concentrations of glucose and NH4+ was not related to the biochemical events of spore germination.

675. The carbon dioxide content of New Zealand Cheddar cheese

1957 ◽  
Vol 24 (2) ◽  
pp. 235-241 ◽  
Author(s):  
P. S. Robertson
Keyword(s):  
Carbon Dioxide ◽  
New Zealand ◽  
Carbon Dioxide Concentration ◽  
Cheddar Cheese ◽  
Carbon Dioxide Content ◽  
Single Strain ◽  
Open Texture ◽  
Factors Influencing ◽  
High Concentrations ◽  
Lower Temperature

Some of the factors influencing the concentration of carbon dioxide found in New Zealand Cheddar cheese have been investigated.1. Cheeses made with the use of commercial starters (containing betacocci) are characterized by a rapid increase in their carbon dioxide content during the 2 weeks following manufacture.2. Cheeses made with the use of single strain starters do not change in carbon dioxide content in the first 2 weeks following manufacture, but may ultimately contain as much carbon dioxide as commercial starter cheeses.3. High concentrations of carbon dioxide within a cheese result in an open texture, especially when the carbon dioxide is formed shortly after manufacture.4. The loss of carbon dioxide to the atmosphere is demonstrated by the existence of a carbon dioxide concentration gradient within the cheese.5. Storage of cheese at a lower temperature than is usual results in retarded carbon dioxide formation.

Factors Influencing Geosmin Production by a Streptomycete and their Relevance to the Occurrence of Earthy Taints in Reservoirs

1983 ◽  
Vol 15 (6-7) ◽  
pp. 191-198 ◽  
Author(s):  
S Wood ◽  
S T Williams ◽  
W R White ◽  
F Jones
Keyword(s):  
Water Mass ◽  
Plant Debris ◽  
Water Supplies ◽  
Biological Origin ◽  
Factors Influencing ◽  
Run Off ◽  
High Concentrations

Water Authorities in the U.K. receive complaints about taste and odours of chemical and biological origin in water supplies. Earthy flavours associated with actinomycetes, cyanobacteria and/or combinations of these are most prevalent. The study area consisted of five large open reservoirs, four of which have sporadic flavour problems. The possible sources of odourous metabolites were studied (water mass, sediment, plant debris, soil run-off). The water mass required high concentrations of nutrients before actinomycetes produced geosmin; such were not reached in the reservoirs. Sediment yielded geosmin after exposure to air for four weeks and plant debris was found to support geosmin production. The soil surrounding the reservoir supports geosmin production and may contaminate the water by run-off or seepage through the reservoir walls.

Measurement of Isocitric Dehydrogenase Activity in Body Fluids

1959 ◽  
Vol 5 (6) ◽  
pp. 509-518 ◽  
Author(s):  
George N Bowers
Keyword(s):  
Standard Deviation ◽  
Dehydrogenase Activity ◽  
Substrate Inhibition ◽  
Body Fluids ◽  
Isocitric Dehydrogenase ◽  
Factors Influencing ◽  
Activity Curve ◽  
High Concentrations ◽  
Healthy Males

Abstract 1. Factors influencing the isocitric dehydrogenase (ICD) activity of serum were studied. Substrate inhibition by high concentrations of isocitrate was observed. 2. The temperature-activity curve of serum ICD was determined. The importance of controlling the temperature of the reaction was stressed. 3. Using this information, a method of measuring the ICD activity in 0.2 ml. of serum is described. 4. The range of ICD activity in 50 healthy males was 30 to 192 units with a mean of 90 units and a standard deviation of ± 34.3 units.

Correlation between protonema morphogenesis and the development of the microtubule system in Funaria spore germination under normal conditions and at high auxin concentrations: an immunofluorescence study

1989 ◽  
Vol 67 (8) ◽  
pp. 2227-2234 ◽  
Author(s):  
N. Ljubešić ◽  
H. Quader ◽  
E. Schnepf
Keyword(s):  
Cell Division ◽  
Spore Germination ◽  
Germ Tube ◽  
Immunofluorescence Study ◽  
Cell Morphogenesis ◽  
Antimicrotubule Agents ◽  
High Concentrations ◽  
High Auxin

Ungerminated spores of Funaria do not contain distinct microtubules but show diffuse antitubulin antibody fluorescence. The microtubules arise when, 24–48 h after sowing, the spores are swollen and the first germ tube begins to protrude. Initially, diffuse fluorescence and microtubules are concentrated around the nucleus. Treatment with auxin at high concentrations (5 × 10−5 – 10−4 M) retards germination and cell division. Like antimicrotubule agents, such as colchicine and chloroisopropyl-N-phenylcarbamate, high auxin concentrations affect the formation of microtubules; either short, irregularly shaped microtubules and fluorescent spots arise, or there is no evidence of microtubules. The auxin effects on growth and microtubules can be reversed in less than 1 day. There is a correlation between the formation of the microtubule system and cell morphogenesis.

The influence of calcium on phytase efficacy in non-ruminant animals

2016 ◽  
Vol 56 (8) ◽  
pp. 1345 ◽  
Author(s):  
C. L. Walk
Keyword(s):  
Small Intestine ◽  
Gastrointestinal Tract ◽  
Binding Sites ◽  
Nutrient Digestibility ◽  
Factors Influencing ◽  
Ruminant Animals ◽  
Ph Conditions ◽  
The Difference ◽  
High Concentrations ◽  
Book Values

High dietary calcium (Ca) can negatively influence growth performance and reduce phosphorus, protein and amino acid digestibility in broilers and pigs. In addition, high dietary Ca will precipitate with phytate at pH conditions within the small intestine. Previous research reported that high dietary Ca significantly reduced phytase efficacy through precipitation with or competition for binding sites on the phytate molecule. However, microbial phytases are active at pH ranges where phytate is soluble and hydrolyse phytate rapidly to reduce the likelihood of phytate precipitating with Ca, suggesting the effect of dietary Ca on the efficacy of these phytases may be reduced. Even with such phytases there may still be problems observed due to particularly high concentrations of dietary Ca, which can occur as a result of a reduction in Ca not being applied in the presence of a phytase and/or if Ca concentrations in the diet exceed expectations. For example, when total Ca was analysed in 795 broiler and pig diets, on average, there was 0.22% more Ca present than expected. This means that if a diet was formulated to contain 0.80% total Ca, the analysed value could be as high as 1.02%, almost 25% above the expected dietary Ca concentration. The discrepancy between the expected and analysed total Ca may have implications on chemical and physical properties within the gastrointestinal tract, dietary phytate solubility, nutrient digestibility and phytase efficacy. The present paper aims to highlight factors influencing the effect of Ca on phytase efficacy, encompassing the differences among published book values for total Ca content of ingredients, the difference between Ca sources and their affinity for phytate, and finally how these factors influence the Ca to P ratio and thus phytase efficacy.

scholarly journals Glucose oxidation and low-density lipoprotein-induced macrophage ceroid accumulation: possible implications for diabetic atherosclerosis

1994 ◽  
Vol 300 (1) ◽  
pp. 243-249 ◽  
Author(s):  
J V Hunt ◽  
M A Bottoms ◽  
K Clare ◽  
J T Skamarauskas ◽  
M J Mitchinson
Keyword(s):  
Glucose Concentration ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Protein Glycation ◽  
Ldl Oxidation ◽  
Low Density ◽  
Catalysed Oxidation ◽  
Induce Lipid Peroxidation ◽  
High Concentrations

The exposure of proteins to high concentrations of glucose in vitro is widely considered a relevant model of the functional degeneration of tissue occurring in diabetes mellitus. In particular, the enhanced atherosclerosis in diabetes is often discussed in terms of glycation of low-density lipoprotein (LDL), the non-enzymic attachment of glucose to apolipoprotein amino groups. However, glucose can undergo transition-metal-catalysed oxidation under near-physiological conditions in vitro, producing oxidants that possess a reactivity similar to the hydroxyl radical. These oxidants can fragment protein, hydroxylate benzoic acid and induce lipid peroxidation in human LDL. In this study, glycation of LDL in vitro is accompanied by such oxidative processes. However, the oxidation of LDL varies with glucose concentration in a manner which does not parallel changes in protein glycation. Glycation increases in proportion to glucose concentration, whereas in our studies maximal oxidation occurs at a glucose concentration of approx. 25 mM. The modification of LDL resulting from exposure to glucose alters macrophage ceroid accumulation, a process which occurs in the human atherosclerotic plaque. The accumulation of ceroid in macrophages is shown to be related to LDL oxidation rather than LDL glycation, per se, as it too occurs at a maximum of approx. 25 mM. Oxidative sequelae of protein glycation appear to be a major factor in LDL-macrophage interactions, at least with respect to ceroid accumulation. Our observations are discussed in the context of the observed increase in the severity of atherosclerosis in diabetes.

scholarly journals Role of GerKB in Germination and Outgrowth of Clostridium perfringens Spores

2009 ◽  
Vol 75 (11) ◽  
pp. 3813-3817 ◽  
Author(s):  
Daniel Paredes-Sabja ◽  
Peter Setlow ◽  
Mahfuzur R. Sarker
Keyword(s):  
Clostridium Perfringens ◽  
Spore Germination ◽  
Nutrient Concentrations ◽  
Wild Type ◽  
Spore Viability ◽  
Colony Forming Efficiency ◽  
Forming Efficiency ◽  
High Concentrations ◽  
Auxiliary Role

ABSTRACT Previous work indicated that Clostridium perfringens gerKA gerKC spores germinate significantly, suggesting that gerKB also has a role in C. perfringens spore germination. We now find that (i) gerKB was expressed only during sporulation, likely in the forespore; (ii) gerKB spores germinated like wild-type spores with nonnutrient germinants and with high concentrations of nutrients but more slowly with low nutrient concentrations; and (iii) gerKB spores had lower colony-forming efficiency and slower outgrowth than wild-type spores. These results suggest that GerKB plays an auxiliary role in spore germination under some conditions and is required for normal spore viability and outgrowth.

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