scholarly journals Comparison of the growth kinetics and proteolytic activities of Chryseobacterium species and Pseudomonas fluorescens

2015 ◽  
Vol 61 (12) ◽  
pp. 977-982 ◽  
Author(s):  
A. Bekker ◽  
L. Steyn ◽  
G. Charimba ◽  
P. Jooste ◽  
C. Hugo
Keyword(s):  
Temperature Gradient ◽  
Pseudomonas Fluorescens ◽  
Proteolytic Activity ◽  
Growth Kinetics ◽  
Effect Of Temperature ◽  
Time Intervals ◽  
Temperature Range ◽  
Growth Studies ◽  
Proteolytic Activities

The effect of temperature on the growth kinetics and proteolytic activity of Chryseobacterium joostei and Chryseobacterium bovis was determined during this study. The results were compared with the activities of Pseudomonas fluorescens, which is regarded to be a major food spoilage psychrotolerant microorganism. For the growth studies, cultures were incubated in nutrient broth in a temperature gradient incubator (from 9 to 50 °C) and separately at 4 °C, and the optical density was measured at different time intervals. Growth temperature profiles for each organism were constructed. For determination of proteolytic activity, the cultures were incubated in fat-free ultra-high temperature processed milk in the temperature gradient incubator for 72 h (temperature range as above). Cell-free extracts were used to determine the proteolytic activity using the azocasein method. Results of the growth studies showed that C. joostei had the ability to grow over a wider temperature range than C. bovis and P. fluorescens without being affected by changes in the temperature. For the proteolytic activity, C. joostei had significantly (p < 0.001) higher activity per milligram of protein at 15.5 °C, followed by C. bovis and P. fluorescens. The results showed that C. joostei potentially has an even greater spoilage capacity in milk on the basis of growth rate and proteolytic activity than did P. fluorescens.

scholarly journals Determination of digestive proteolytic profile in the larvae of Dyspessa palidata (Staudinger) (Lepidoptera: Cossidae)

2015 ◽  
Vol 47 (3) ◽  
pp. 91
Author(s):  
M. Mardani-Talaee ◽  
A. Zibaee
Keyword(s):  
Proteolytic Activity ◽  
Cathepsin B ◽  
Posterior Midgut ◽  
Ph Dependency ◽  
Metalloproteinase Inhibitors ◽  
Optimal Value ◽  
Important Pest ◽  
Proteolytic Activities ◽  
Membrane Bound

Digestive proteolytic profile was determined in the larvae of <em>Dyspessa palidata</em> (Staudinger), which is the most important pest of Alliaceae in Europe and Iran. Compartmentalisation of the proteolytic activities by considering soluble and membrane-bound fractions revealed that soluble fractions of the whole midgut preparations had higher general proteolytic activity than membrane-bound fractions. Also, four proteolytic bands were observed in the soluble fraction of the total midgut preparation in electrophoresis. Compartmentalisation of the specific proteases revealed presence of trypsin, elastase, aminoand carboxy peptidases in posterior midgut but the highest activities of other proteases were found in anterior midgut. The highest activity of general protease was found at pHs of 6 and 8. Also, pH dependency of trypsin, chymotrypsin and elastase were found at values of 8, 7-8 and 9 but cathepsins had the optimal pH at 6. Exopeptidases showed the optimal value at pH of 7 although carboxypeptidase showed same activity at values of 6 and 7. The inhibitory concentrations 50% (IC<sub>50</sub>) of AEBSF.HCL on trypsin, chymotrypsin and elastase proteases were found to be 3.69, 3.31 and 4.09 mM, respectively. IC<sub>50</sub> concentrations of TLCK, SBTI and TPCK significantly inhibited trypsin and chymotrypsin activities. IC<sub>50</sub> of E-64 were 3.67 and 4.16 mM on cathepsin B and L but cystatin revealed 5.22 and 4.48 mM concentrations on cathepsin B and L, respectively. EDTA and phenathroline as metalloproteinase inhibitors had IC<sub>50</sub> of 3.25 and 3.91 mM on general proteolytic activity. Results of the current study revealed larvae of <em>D. palidata</em> utilised different proteases to increase digestive efficiency when they fed on the host plants containing several toxic molecules.

scholarly journals The effect of temperature on the viscosity of air

1926 ◽  
Vol 113 (763) ◽  
pp. 233-237 ◽  
Keyword(s):  
Present Author ◽  
Effect Of Temperature ◽  
Appreciable Change ◽  
Temperature Range ◽  
Higher Temperature ◽  
The Difference ◽  
Experimental Values ◽  
Coefficient Of Viscosity ◽  
Slight Alteration

In a recent paper Prof. A. 0. Rankine has put forward a number of criticisms of the results obtained from, and the experimental method employed in, the determination of the temperature coefficient of viscosity of air by the present author. In the first place, a comparison is drawn between the author’s results and those of other observers in the lower part of the temperature range, and the conclusion is drawn therefrom that there is a possibility of an error of 3 percent, in the author’s measurements throughout the whole range of temperature used. This inference is reached from the figures quoted in Table II of Rankine’s paper, in which the temperature range from 15° to 183° C. is considered. That some difference exists between the author’s results and those of other observers in the lower part of the temperature range is clear, but it must again be emphasised that the values given for low temperatures are not experimental values, but were obtained by an extension of the graph (fig. 2) for higher temperature measurements to the value of the viscosity as given by Millikanj for room temperatures. A slight alteration of the curvature of this extension would make an appreciable change in the ratios η100/η15 and η183/η15 , but this would not be sufficient to account for the curvature at B in fig. 3 of the original paper. If the values of T ⅜ /η for Breitenbach’s results at 182° C. and 302° C. are plotted on this curve, they lie above the present results and on a curve which would intersect AB at about 600° C. That part of the difference is due to this cause seems to be indicated by the fact that the difference diminishes as the temperature rises. Thus at 300° C. the following values of η300/η15 are obtained by Breitenbach, the only other worker at this temperature, and the author. The figures used are those given by Rankine.

scholarly journals SOME TEMPERATURE CHARACTERISTICS IN MAN

1935 ◽  
Vol 18 (3) ◽  
pp. 399-408 ◽  
Author(s):  
Hudson Hoagland ◽  
Clifton T. Perkins
Keyword(s):  
Human Heart ◽  
Heart Beat ◽  
Effect Of Temperature ◽  
Time Intervals ◽  
Temperature Characteristics ◽  
Temperature Range ◽  
Master Reaction ◽  
Short Time

The value of µ = 29,400 has been found for the human heart beat over the temperature range of approximately 4.7°C. This value is different from that of 24,000 calories which has been obtained for the effect of temperature on judgments of short durations. The evidence indicates that the estimation of short time intervals is controlled by a chemical master reaction which is independent of the pulse rhythm.

Acetylene chemisorption at palladium: Effect of temperature and structure of the surface

1984 ◽  
Vol 49 (6) ◽  
pp. 1448-1458
Author(s):  
Josef Kopešťanský
Keyword(s):  
Work Function ◽  
Atomic Hydrogen ◽  
Effect Of Temperature ◽  
Thermally Stable ◽  
Template Effect ◽  
Temperature Range ◽  
Adsorbed Layers ◽  
Different Types ◽  
Adsorption Complexes ◽  
Low Coverage

The effect of temperature and structure of the palladium surfaces on acetylene chemisorption was studied along with the interaction of the adsorbed layers with molecular and atomic hydrogen. The work function changes were measured and combined with the volumetric measurements and analysis of the products. At temperature below 100 °C, acetylene is adsorbed almost without dissociation and forms at least two different types of thermally stable adsorption complexes. Acetylene adsorbed at 200 °C is partly decomposed, especially in the low coverage region. Besides the above mentioned effects, the template effect of adsorbed acetylene was studied in the temperature range from -80° to 25 °C. It has been shown that this effect is a typical phenomenon of the palladium-acetylene system which is not due to surface impurities.

scholarly journals A PROCEDURE FOR THE DETERMINATION OF PROTEOLYTIC ACTIVITY

1950 ◽  
Vol 182 (2) ◽  
pp. 821-828
Author(s):  
Beat M. Iselin ◽  
Carl. Niemann
Keyword(s):  
Proteolytic Activity

Metabolic response to temperature stress in the Colombian freshwater crab Neostrengeria macropa (H. Milne Edwards, 1853) (Decapoda: Brachyura: Pseudothelphusidae)

2021 ◽  
Author(s):  
David M Hudson
Keyword(s):  
Metabolic Response ◽  
Infrastructure Development ◽  
Predator Prey ◽  
Temperature Range ◽  
Indicator Group ◽  
Response To Temperature ◽  
Performance Results ◽  
The City ◽  
The Ideal

Abstract Freshwater crustaceans are distributed throughout the montane and lowland areas of Colombia, and are therefore a useful indicator group for how aquatic species will respond to climate change. As such, metabolic determination of physiological performance was evaluated for the Colombian pseudothelphusid crab, Neostrengeria macropa (H. Milne Edwards, 1853), over a temperature range inclusive of current temperatures and those predicted by future scenarios in the plateau around the city of Bogotá, namely from 8 °C to 30 °C. The performance results mostly aligned with previous exploratory behavioral determination of the ideal temperature range in the same species, although the metabolism increased at the highest temperature treatments, a point when exploratory behavior declined. These results indicate that this species of montane crab behaviorally compensates for increased thermal stress by decreasing its physical activity, which could have negative predator-prey consequences with changes to community structure as different species undergo climate-mediated geographic range shifts in the region. As this species is endemic to the plateau surrounding Bogotá, it also experiences a number of other stressors to its survival, including infrastructure development and invasive species.

scholarly journals A Milk Foodomics Investigation into the Effect of Pseudomonas fluorescens Growth under Cold Chain Conditions

Foods ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1173
Author(s):  
Paolo Bellassi ◽  
Gabriele Rocchetti ◽  
Lorenzo Morelli ◽  
Biancamaria Senizza ◽  
Luigi Lucini ◽  
...  
Keyword(s):  
Pseudomonas Fluorescens ◽  
Degradation Products ◽  
Storage Conditions ◽  
Cold Chain ◽  
Lower Sensitivity ◽  
Multivariate Statistical ◽  
Proteolytic Activities ◽  
Quality Of Milk ◽  
Potential Tool

Pseudomonas fluorescens is a psychrotrophic species associated with milk spoilage because of its lipolytic and proteolytic activities. Consequently, monitoring P. fluorescens or its antecedent activity in milk is critical to preventing quality defects of the product and minimizing food waste. Therefore, in this study, untargeted metabolomics and peptidomics were used to identify the changes in milk related to P. fluorescens activity by simulating the low-temperature conditions usually found in milk during the cold chain. Both unsupervised and supervised multivariate statistical approaches showed a clear effect caused by the P. fluorescens inoculation on milk samples. Our results showed that the levels of phosphatidylglycerophosphates and glycerophospholipids were directly related to the level of contamination. In addition, our metabolomic approach allowed us to detect lipid and protein degradation products that were directly correlated with the degradative metabolism of P. fluorescens. Peptidomics corroborated the proteolytic propensity of P. fluorescens-contaminated milk, but with lower sensitivity. The results obtained from this study provide insights into the alterations related to P. fluorescens 39 contamination, both pre and post heat treatment. This approach could represent a potential tool to retrospectively understand the actual quality of milk under cold chain storage conditions, either before or after heat treatments.

Cortical reaction as an egg quality indicator in artificial reproduction of pikeperch, Sander lucioperca

2012 ◽  
Vol 24 (6) ◽  
pp. 843 ◽  
Author(s):  
Daniel Żarski ◽  
Sławomir Krejszeff ◽  
Katarzyna Palińska ◽  
Katarzyna Targońska ◽  
Krzysztof Kupren ◽  
...  
Keyword(s):  
Quality Evaluation ◽  
Egg Quality ◽  
Effect Of Temperature ◽  
Artificial Reproduction ◽  
Female Fish ◽  
Sander Lucioperca ◽  
Embryo Survival ◽  
Hormonal Stimulation ◽  
Cortical Reaction

The aim of this study was to investigate the process of the cortical reaction in eggs of pikeperch, Sander lucioperca (L.), as well as the application of microscopic assessment of this process in egg quality evaluation. The analysis was carried out with eggs obtained from 10 females by artificial reproduction, in which hormonal stimulation with hCG was applied. Subsequently, each sample of eggs (separately from each female fish) was analysed. The analysis included observation of the cortical reaction and the process of egg swelling, and determination of the effect of temperature (12, 14 and 16°C) and the presence of spermatozoa on the cortical reaction. The results indicate that the cortical reaction in pikeperch eggs is quite violent, resulting in visible deformation of eggs between 3 and 5 min after activation. No effect of temperature or the presence of spermatozoa on the cortical reaction was observed. A strong correlation was recorded for the percentage of egg deformations observed and embryo survival rate. The described method of determination of pikeperch egg quality (based on egg deformation rate between 3 and 5 min after activation) may be highly useful, both in scientific research (where high-quality eggs are required) and in hatchery practice.

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