Aerobio Growth of Listeria monocytogenes on Beef Lean and Fatty Tissue: Equations Describing the Effects of Temperature and pH

1993 ◽  
Vol 56 (2) ◽  
pp. 96-101 ◽  
Author(s):  
FREDERICK H. GRAU ◽  
PAUL B. VANDERLINDE
Keyword(s):  
Growth Rate ◽  
Listeria Monocytogenes ◽  
Goodness Of Fit ◽  
Effect Of Temperature ◽  
Fatty Tissue ◽  
Lean Tissue ◽  
Generation Times ◽  
Lag Period ◽  
Effects Of Temperature ◽  
Lag Times

The aerobio growth rate and the duration of the lag period were determined for Listeria monocytogenes strain Murray B growing on ground beef lean and on pieces of fatty tissue. The organism grew at 0°C on lean tissue at pH ≥ 6 and on fatty tissue. It failed to grow at 0°C on lean at pH 5.6 but did grow at 2.5°C. The effect of temperature, between 0 and 30°C, on the growth rate on fatty tissue can be described by a modified Arrhenius equation Ln (gen/h) = −205.73 + 1.2939 × 105/K −2.0298 × 107/K2, where K = °Kelvin. This equation accounted for 99.7% of the variance. The combined effect of temperature and pH on the growth rate on beef lean was described by Ln (gen/h) = − 232.64 + 1.4041 × 105/K - 2.1908 × 107K2 + 1.1586 × 102/pH - 4.0952 × 102/pH2 (variance accounted for 99.5%). For lean at about pH 5.5–5.6, this equation applied between about 2.5 and 35°C; for lean of pH 6–7, it applied between about 0 and 35°C. Though the lag period increased with decrease in temperature and pH, measured lag times were more variable than generation times, and the goodness of fit of modified Arrhenius equations to lag times was relatively poor (variance accounted for 83–92%).

scholarly journals The Effect of Temperature and Humidity May Reduce the Growth Rate of the Coronavirus Disease 2019 Epidemic

2020 ◽  
Author(s):  
Lei Qin ◽  
Qiang Sun ◽  
Jiani Shao ◽  
Yang Chen ◽  
Xiaomei Zhang ◽  
...  
Keyword(s):  
Growth Rate ◽  
Relative Humidity ◽  
Effect Of Temperature ◽  
Average Temperature ◽  
Temperature And Humidity ◽  
Scatter Plots ◽  
Low Humidity ◽  
Average Relative Humidity ◽  
Effects Of Temperature ◽  
The Relationship

Abstract Background: The effects of temperature and humidity on the epidemic growth of coronavirus disease 2019 (COVID-19)remains unclear.Methods: Daily scatter plots between the epidemic growth rate (GR) and average temperature (AT) or average relative humidity (ARH) were presented with curve fitting through the “loess” method. The heterogeneity across days and provinces were calculated to assess the necessity of using a longitudinal model. Fixed effect models with polynomial terms were developed to quantify the relationship between variations in the GR and AT or ARH.Results: An increased AT dramatically reduced the GR when the AT was lower than −5°C, the GR was moderately reduced when the AT ranged from −5°C to 15°C, and the GR increased when the AT exceeded 15°C. An increasedARH increased theGR when the ARH was lower than 72% and reduced theGR when the ARH exceeded 72%.Conclusions: High temperatures and low humidity may reduce the GR of the COVID-19 epidemic. The temperature and humidity curves were not linearly associated with the COVID-19 GR.

scholarly journals Studies in the geotropism of the pteridophyta V—Some effects of temperature on growth and geotropism in Asplenium bulbiferium

1935 ◽  
Vol 116 (800) ◽  
pp. 479-493 ◽  
Keyword(s):  
Growth Rate ◽  
Effect Of Temperature ◽  
Horizontal Position ◽  
Present Position ◽  
Minimum Period ◽  
Plant Life ◽  
Latent Time ◽  
Presentation Time ◽  
Effects Of Temperature ◽  
The Given

Although temperature and gravity both influence plant life, and although both factors have been studied for many decades, there is surprisingly little literature decades, there is surprisingly little literature dealing with the relation between the two; and none, so far as I can discover, on the effect in any Pteridophyte. Navez (1929) who criticized the work of some investigators on the effect of temperature on the geotropism of a few seedlings, sums up the present position in his remark that the conclusions of workers are very different and often in opposition. The present paper gives the results of 1100 experiments carried out mainly between the years 1922 and 1927, and though it is realized that much remains to be done on the question, it is believed that the results which have been obtained are of some value. For general methods, reference may be made to previous “Studies” in this series. Geotropic sensitivity, as measured by presentation time at different stages in development of the frond, was fully worked out by Waight (1923) for 20°C, and is adopted here as a standard of reference. The growth rate recorded in the tables is that for the particular frond under investigation, or is the average of the fronds examined during the day of the experiment. Nearly all the experiments included in the tables were conducted during the months of April-October, as I have since been able to show that there is an annual rhythm in geotropic irritability. A decrease in sensitivity occurs in winter, and hence experiments performed in November-March are not strictly comparable with those carried out in the summer. The following abbreviations are used:- P.S. = period of stimulation. P.T. = presentation time, i. e ., the minimum period of stimulation in a horizontal position, which, under the given conditions, will cause a movement of approximately 5° in about 80% of the fronds. L.T. = latent time (Prankerd, 1925) in hours. N = “normal time,” i. e ., the P.T. For different stages of the frond at 20°C (see Waight, 1923).

scholarly journals Growth, stoichiometry and cell size; temperature and nutrient responses in haptophytes

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3743 ◽  
Author(s):  
Lars Fredrik Skau ◽  
Tom Andersen ◽  
Jan-Erik Thrane ◽  
Dag Olav Hessen
Keyword(s):  
Growth Rate ◽  
High Temperature ◽  
Cell Size ◽  
Marine Phytoplankton ◽  
Effect Of Temperature ◽  
Elemental Content ◽  
Specific Content ◽  
Batch Cultures ◽  
P Limitation ◽  
Effects Of Temperature

Temperature and nutrients are key factors affecting the growth, cell size, and physiology of marine phytoplankton. In the ocean, temperature and nutrient availability often co-vary because temperature drives vertical stratification, which further controls nutrient upwelling. This makes it difficult to disentangle the effects of temperature and nutrients on phytoplankton purely from observational studies. In this study, we carried out a factorial experiment crossing two temperatures (13°and 19°C) with two growth regimes (P-limited, semi-continuous batch cultures [“−P”] and nutrient replete batch cultures in turbidostat mode [“+P”]) for three species of common marine haptophytes (Emiliania huxleyi, Chrysochromulina rotalis and Prymnesium polylepis) to address the effects of temperature and nutrient limitation on elemental content and stoichiometry (C:N:P), total RNA, cell size, and growth rate. We found that the main gradient in elemental content and RNA largely was related to nutrient regime and the resulting differences in growth rate and degree of P-limitation, and observed reduced cell volume-specific content of P and RNA (but also N and C in most cases) and higher N:P and C:P in the slow growing −P cultures compared to the fast growing +P cultures. P-limited cells also tended to be larger than nutrient replete cells. Contrary to other recent studies, we found lower N:P and C:P ratios at high temperature. Overall, elemental content and RNA increased with temperature, especially in the nutrient replete cultures. Notably, however, temperature had a weaker–and in some cases a negative–effect on elemental content and RNA under P-limitation. This interaction indicates that the effect of temperature on cellular composition may differ between nutrient replete and nutrient limited conditions, where cellular uptake and storage of excess nutrients may overshadow changes in resource allocation among the non-storage fractions of biomass (e.g. P-rich ribosomes and N-rich proteins). Cell size decreased at high temperature, which is in accordance with general observations.

scholarly journals Exposure to Salt and Organic Acids Increases the Ability of Listeria monocytogenes To Invade Caco-2 Cells but Decreases Its Ability To Survive Gastric Stress

2006 ◽  
Vol 72 (8) ◽  
pp. 5384-5395 ◽  
Author(s):  
Matthew R. Garner ◽  
Karen E. James ◽  
Michelle C. Callahan ◽  
Martin Wiedmann ◽  
Kathryn J. Boor
Keyword(s):  
Listeria Monocytogenes ◽  
Organic Acids ◽  
Response Regulator ◽  
Gastric Fluid ◽  
Stress Exposure ◽  
Infectious Dose ◽  
Generation Times ◽  
Maximum Cell ◽  
Phase Temperature ◽  
Effects Of Temperature

ABSTRACT The effects of environmental stress exposure on Listeria monocytogenes growth and virulence-associated characteristics were investigated. Specifically, we measured the effects of temperature (7 or 37°C), pH (5.5 or 7.4), the presence of salt and organic acids (375 mM NaCl, 8.45 mM sodium diacetate [SD], 275 mM sodium lactate [SL], or a combination of NaCl, SD, and SL), and deletion of sigB, which encodes a key stress response regulator, on the ability of L. monocytogenes to grow, invade Caco-2 cells, and survive exposure to synthetic gastric fluid (pH 2.5 or 4.5). Our results indicate that (i) L. monocytogenes log-phase generation times and maximum cell numbers are not dependent on the alternative sigma factor σB in the presence of NaCl and organic acids at concentrations typically found in foods; (ii) growth inhibition of L. monocytogenes through the addition of organic acids is pH dependent; (iii) the ability of L. monocytogenes to invade Caco-2 cells is affected by growth phase, temperature, and the presence of salt and organic acids, with the highest relative invasion capabilities observed for cells grown with SL or NaCl at 37°C and pH 7.4; (iv) growth of L. monocytogenes in the presence of NaCl, SD, or SL reduces its ability to survive exposure to gastric fluid; and (v) exposure of L. monocytogenes to gastric fluid reduces the enhanced invasiveness caused by growth in the presence of NaCl or SL. These findings suggest that virulence-associated characteristics that determine the L. monocytogenes infectious dose are likely to be affected by food-specific properties (e.g., pH or the presence of salt or organic acid).

scholarly journals From individuals to populations: How intraspecific competition shapes thermal reaction norms

2019 ◽  
Author(s):  
François Mallard ◽  
Vincent Le Bourlot ◽  
Christie Le Coeur ◽  
Monique Avnaim ◽  
Romain Péronnet ◽  
...  
Keyword(s):  
Growth Rate ◽  
Population Dynamics ◽  
Intraspecific Competition ◽  
Thermal Reaction ◽  
Reaction Norms ◽  
Effect Of Temperature ◽  
Dominant Factor ◽  
List Type ◽  
Joint Effects ◽  
Effects Of Temperature

AbstractMost ectotherms follow the temperature-size rule (TSR): in cold environments individuals grow slowly but reach a large asymptotic length. Intraspecific competition can induce plastic changes of growth rate and asymptotic length and competition may itself be modulated by temperature.Our aim is to disentangle the joint effects of temperature and intraspecific competition on growth rate and asymptotic length.We used two distinct clonal lineages of the Collembola Folsomia candida, to describe thermal reaction norms of growth rate, asymptotic length and reproduction over 6 temperatures between 6°C and 29°C. In parallel, we measured the long-term size-structure and dynamics of populations reared under the same temperatures to measure growth rates and asymptotic lengths in populations and to quantify the joint effects of competition and temperature on these traits.We show that intraspecific competition modulates the temperature-size rule. In dense populations there is a direct negative effect of temperature on asymptotic length, but there is no temperature dependence of the growth rate, the dominant factor regulating growth being competition. We fail to demonstrate that the strength of competition varies with temperature except at the lowest temperature where competition is minimal. The two lineages responded differently to the joint effects of temperature and competition and these genetic differences have marked effects on population dynamics along our temperature gradient.Our results reinforce the idea that the TSR response of ectotherms can be modulated by biotic and abiotic stressors when studied in non-optimal laboratory experiments. Untangling complex interactions between environment and demography will help understanding how size will respond to environmental change and how climate change may influence population dynamics.

Effect of average daily food intake on production performance in growing pigs

1988 ◽  
Vol 46 (1) ◽  
pp. 111-122 ◽  
Author(s):  
E. Kanis
Keyword(s):  
Growth Rate ◽  
Food Intake ◽  
Tissue Growth ◽  
Growing Pigs ◽  
Fatty Tissue ◽  
Food Conversion ◽  
Lean Tissue ◽  
Daily Food Intake ◽  
Daily Food ◽  
Second Degree

ABSTRACTEffects of daily food intake (FI) on daily gain (DG), food conversion ratio (FCR), ultrasonic backfat thickness (BF), proportion of lean parts (LP), proportion of fatty parts (FP), lean tissue growth rate (LTGR), fatty tissue growth rate (FTGR) and lean tissue food conversion (LTFC) were investigated in 687 barrows and 98 gilts, slaughtered at a mean live weight of 108 kg and fattened in seven batches. In the range of food intake from about 1·7 to 3·2 kg/day (22 to 42 MJ digestible energy) a continuous distribution of data was available.Body composition was linearly related to FI. Most regressions of BF and all of LP and of FP on FI were linear, showing fatter animals at higher food intake. For FTGR, BF, LP and FP, parameter estimates based on linear regression were given. Although the response of DG and of LTGR on increasing FI was not always significantly different from linearity, the second degree polynomials indicated diminishing returns in all batches. FTGR had a high linear correlation with FI (0·85 to 0·95), indicating that in the present range of FI a rather fixed proportion of the food was used to deposit fatty tissue.For DG and LTGR a non-linear model of the type a(FI -fo)b was fitted, where fo was interpreted as maintenance requirement. For FCR and LTFC the corresponding model was FI/(α(FI — fo)b). Both models were preferred over second degree polynomials because of better interpretation of parameters. FCR and LTFC showed minima at about 2·6 and 2·2 kg/day food intake, but especially for FCR the increase at increasing FI was low. Results were not consistent in demonstrating or refuting a plateau in LTGR, which in any event appears to lie near to or beyond ad libitum FI for most pigs.

scholarly journals Effects of Temperature on Ethylene-induced Phenylalanine Ammonia Lyase Activity and Russet Spotting in Harvested Iceberg Lettuce

1995 ◽  
Vol 120 (1) ◽  
pp. 84-87 ◽  
Author(s):  
M.A. Ritenour ◽  
M.J. Ahrens ◽  
M.E. Saltveit
Keyword(s):  
Phenolic Compounds ◽  
Phenylalanine Ammonia Lyase ◽  
Rapid Decrease ◽  
Effect Of Temperature ◽  
Pal Activity ◽  
Iceberg Lettuce ◽  
Lyase Activity ◽  
Lag Period ◽  
Effects Of Temperature ◽  
Phenylalanine Ammonia Lyase Activity

Experiments were conducted to study the effect of temperature on the ethylene inducibility of phenylalanine ammonia lyase (PAL, EC 4.3.1.5) activity and the development of russet spotting (RS) in Iceberg lettuce (Lactucu sutiva L.). Tissue exposed to ethylene and held at 15 or 20C showed earlier hut lower peaks in PAL activity than tissue held at 5C. Accumulation of total soluble phenolic compounds, and the development of RS paralleled increases in PAL activity after a short lag period. Lettuce tissue transferred from 5 to 15C after 1 to 3 days showed later hut higher peaks in PAL activity than tissue continuously held at 15C. Transferring ethylene-exposed tissue to 0C before RS symptoms developed greatly limited further rise in PAL activity and RS development. Discontinuing ethylene exposure after 4 days resulted in a rapid decrease in PAL activity. Lettuce tissue exposed to ethylene for 4 days and then transferred from 5 to 0C after the development of moderate RS symptoms showed no difference in RS after 8 days compared to tissue stored continuously at 5C.

Effect of temperature during the synthesis process of CdSe nanoparticles using the colloidal technique

MRS Advances ◽  
2020 ◽  
Vol 5 (63) ◽  
pp. 3389-3395
Author(s):  
R. González-Díaz ◽  
D. Fernández-Sánchez ◽  
P. Rosendo-Francisco ◽  
G. Sánchez-Legorreta
Keyword(s):  
Scanning Tunneling Microscope ◽  
Electron Cloud ◽  
Cdse Nanoparticles ◽  
Effect Of Temperature ◽  
Synthesis Process ◽  
Scanning Tunneling ◽  
Tunneling Microscope ◽  
First Results ◽  
Effects Of Temperature ◽  
Scanning Electron

AbstractIn this work, the first results of the effects of temperature during the production of Se2- ions and the effect during the interaction of Cd2+ and Se2- ions in the synthesis process of CdSe nanoparticles are presented. The synthesis of CdSe was carried out by the colloidal technique, in the first one we used a temperature of 63 °C to produce Se2- ions and in the second one an interaction temperature of 49 °C. The samples were characterized using a Scanning Electron Microscope (SEM) and a Scanning Tunneling Microscope (STM). From the SEM micrographs it was possible to identify the thorns formation and irregular islands. STM micrographs reveal elliptical shapes with a regular electron cloud profile.

Comparison of copper sulphate pentahydrate growth rates determined by different methods

1990 ◽  
Vol 55 (7) ◽  
pp. 1691-1707 ◽  
Author(s):  
Miloslav Karel ◽  
Jiří Hostomský ◽  
Jaroslav Nývlt ◽  
Axel König
Keyword(s):  
Growth Rate ◽  
Crystal Growth ◽  
Fluidized Bed ◽  
Growth Rates ◽  
Copper Sulphate ◽  
Crystal Growth Rate ◽  
Effect Of Temperature ◽  
Rotating Disc ◽  
Shape Factors ◽  
Data Treatment

Crystal growth rates of copper sulphate pentahydrate (CuSO4.5 H2O) determined by different authors and methods are compared. The methods included in this comparison are: (i) Measurement on a fixed crystal suspended in a streaming solution, (ii) measurement on a rotating disc, (iii) measurement in a fluidized bed, (iv) measurement in an agitated suspension. The comparison involves critical estimation of the supersaturation used in measurements, of shape factors used for data treatment and a correction for the effect of temperature. Conclusions are drawn for the choice of values to be specified when data of crystal growth rate measurements are published.

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