Effects of low temperature on growth parameters in the entomopathogenic fungus Metarhizium anisopliae

1999 ◽  
Vol 45 (12) ◽  
pp. 1055-1061 ◽  
Author(s):  
J N Amritha De Croos ◽  
Michael J Bidochka
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Metarhizium Anisopliae ◽  
Entomopathogenic Fungus ◽  
Incubation Temperature ◽  
Growth Parameters ◽  
Conidia Production ◽  
Cold Active ◽  
Germination And Growth ◽  
Cold Activity

The effects of temperature (8°C, 15°C, and 22°C) on germination, growth rate and conidia production in thirty-two isolates of the entomopathogenic fungus Metarhizium anisopliae were assessed. Most isolates were obtained from various locations in Ontario, Canada. Ten out of thirty-two (31.3%) isolates were deemed cold-active because of their ability to grow at 8°C. Growth rates in all isolates increased as the incubation temperature was increased. There were significant differences in growth rates and conidia production among isolates. However, conidia production had no relationship with a growth rate. With respect to the geographical origin, there was no general relationship between latitude and growth rates. However, we found that all the cold-active isolates were isolated from the more northern sites and no isolate originating below 43.5° latitude showed cold activity. Cold-active germination and growth of this biocontrol fungus have implications for strain selection and application in Canadian insect control efforts.Key words: Metarhizium anisopliae, cold activity, entomopathogen.

scholarly journals Growth of Listeria monocytogenes in Thawed Frozen Foods

2017 ◽  
Vol 80 (3) ◽  
pp. 447-453 ◽  
Author(s):  
Ai Kataoka ◽  
Hua Wang ◽  
Philip H. Elliott ◽  
Richard C. Whiting ◽  
Melinda M. Hayman
Keyword(s):  
Growth Rate ◽  
Listeria Monocytogenes ◽  
Growth Rates ◽  
Storage Temperature ◽  
Growth Parameters ◽  
Quadratic Model ◽  
Lag Phase ◽  
Frozen Foods ◽  
Phase Duration ◽  
Primary Model

ABSTRACT The growth characteristics of Listeria monocytogenes inoculated onto frozen foods (corn, green peas, crabmeat, and shrimp) and thawed by being stored at 4, 8, 12, and 20°C were investigated. The growth parameters, lag-phase duration (LPD) and exponential growth rate (EGR), were determined by using a two-phase linear growth model as a primary model and a square root model for EGR and a quadratic model for LPD as secondary models, based on the growth data. The EGR model predictions were compared with growth rates obtained from the USDA Pathogen Modeling Program, calculated with similar pH, salt percentage, and NaNO2 parameters, at all storage temperatures. The results showed that L. monocytogenes grew well in all food types, with the growth rate increasing with storage temperature. Predicted EGRs for all food types demonstrated the significance of storage temperature and similar growth rates among four food types. The predicted EGRs showed slightly slower rate compared with the values from the U.S. Department of Agriculture Pathogen Modeling Program. LPD could not be accurately predicted, possibly because there were not enough sampling points. These data established by using real food samples demonstrated that L. monocytogenes can initiate growth without a prolonged lag phase even at refrigeration temperature (4°C), and the predictive models derived from this study can be useful for developing proper handling guidelines for thawed frozen foods during production and storage.

Incubation temperature and clutch effects on initial body sizes and growth rates in green iguana hatchlings (Iguana iguana)

2017 ◽  
Vol 67 (3-4) ◽  
pp. 239-249 ◽  
Author(s):  
Yuleimis T. Martínez-Caballero ◽  
Brian C. Bock ◽  
Isabel Pérez ◽  
Ángela M. Ortega-León ◽  
Vivian P. Páez
Keyword(s):  
Growth Rate ◽  
Body Size ◽  
Growth Rates ◽  
Egg Size ◽  
Incubation Temperature ◽  
Size Variation ◽  
Early Growth ◽  
Rate Variation ◽  
Body Sizes ◽  
Green Iguanas

Large initial body size and rapid early growth rate are important in many species, both because predation rates decline as individuals grow and because females that attain a larger adult body size are more fecund. To identify possible factors contributing to size and growth rate variation in hatchling green iguanas, we artificially incubated six clutches at three constant temperatures to test for effects of incubation temperature and/or clutch effects on initial size and growth rate. Higher incubation temperatures resulted in significantly shorter incubation periods but did not influence initial body size. There were significant differences among clutches in egg size, and also in initial hatchling body size, even after correcting for differences in egg size among clutches. A subset of hatchlings from each nest was reared in semi-natural conditions for four months, with individuals from the high incubation temperature condition exhibiting the slowest longer-term growth rates. No clutch effects were detected in the growth rate analyses. The observed variation in early growth rate of juvenile iguanas seems to be selectively important and this variation may be due in part to the conditions the eggs experience during incubation, but clutch effects in this study were limited to egg size and initial hatchling body size variation, but were not found for subsequent growth rates.

scholarly journals The effect of temperature and water activity on the growth of Staphylococcus aureus

2010 ◽  
Vol 27 (Special Issue 2) ◽  
pp. 28-35 ◽  
Author(s):  
A. Medveďová ◽  
Ľ. Valík ◽  
A. Studeničová
Keyword(s):  
Staphylococcus Aureus ◽  
Growth Rate ◽  
Sodium Chloride ◽  
Water Activity ◽  
Specific Growth ◽  
Incubation Temperature ◽  
Growth Parameters ◽  
Effect Of Temperature ◽  
Extended Model ◽  
Growth Responses

The growth responses of Staphylococcus aureus 2064 as affected by water activity and incubation temperature were studied in two different laboratory media. Growth parameters at temperatures from 7 to 51&deg;C and a<sub>w</sub> in the range from 1.0 to 0.86 were fitted using Ratkowsky models. The effect of temperature within its whole range on the specific growth rate was modelled by the extended model under the following equation: &radic;&micro; = 0.0456 (T &ndash; T<sub>min</sub>) [1 &ndash; e<sup>0.447(T &ndash; T<sub>max</sub>)</sup>]. The water activity values of tested media were adjusted by sodium chloride in the range from a<sub>w</sub> = 1.0 to 0.86 and experiments were conducted at 15 and 18&deg;C. The growth responses of S. aureus on water activity at 15&deg;C and 18&deg;C in PCA broth and BHI broth was described by simplified Ratkowsky model in the form: &radic;&micro; = b &times; a<sub>w</sub>. Validation of the found relationships confirmed sound fitting of the data and thus the referred results of the isolate originated from ewes&rsquo; cheese can be used in the growth prediction of S. aureus, reliably.

Performance of a-Si-H Solar Cells at Higher Growth Rates

1999 ◽  
Vol 557 ◽  
Author(s):  
G. Ganguly ◽  
G. Lin ◽  
L.F. Chen ◽  
M. He ◽  
G. Wood ◽  
...  
Keyword(s):  
Growth Rate ◽  
Solar Cells ◽  
Growth Rates ◽  
Growth Parameters ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Growth Conditions ◽  
Plasma Decomposition ◽  
Hydrogen Mixtures ◽  
External Growth

AbstractWe have studied the effects of external growth parameters during the deposition of the i-layers of a-Si p-i-n solar cells using dc plasma decomposition of silane-hydrogen mixtures at growth rates of up to 3A/s. The loss of initial performance with increasing growth rate is mainly due to a loss of short-circuit current. The relative degradation of efficiency upon extended light soaking also increases with growth rate, and is mainly due to a decrease in the fill factor. Systematic comparisons of the performance and its degradation with changes in growth conditions reveal that these two components of the total degradation have distinct origins.

Influence of growth parameters on the microstructure of directionally solidified Bi2Sr2CaCu2Oy

1990 ◽  
Vol 5 (9) ◽  
pp. 1834-1849 ◽  
Author(s):  
M. J. Cima ◽  
X. P. Jiang ◽  
H. M. Chow ◽  
J. S. Haggerty ◽  
M. C. Flemings ◽  
...  
Keyword(s):  
Growth Rate ◽  
Directional Solidification ◽  
Growth Rates ◽  
Growth Parameters ◽  
Directionally Solidified ◽  
Primary Solidification Phase ◽  
Float Zone ◽  
The Matrix ◽  
Laser Heated ◽  
Planar Growth

Laser-heated float zone growth was used to study the directional solidification behavior of Bi–Sr–Ca–Cu–O superconductors. The phases that solidify from the melt, their morphology, and their composition are altered by growth rate. Highly textured microstructures are achieved by directional solidification at all growth rates. The superconducting phase is found always to have the composition Bi2.5Sr2CaCu2.2Oy when grown from boules with composition 2:2:1:2 (BiO1.5:SrO:CaO:CuO). Planar growth fronts of Bi2.5Sr2CaCu2.2Oy are observed when the temperature gradient divided by the growth rate (G/R) is larger than 3 ⊠ 1011 K-s/m2 in 2.75 atm oxygen. Thus, the 2212 compound was observed to solidify directly from the melt at the slowest growth rates used in this study. Measurement of the steady-state liquid zone composition indicates that it becomes bismuth-rich as the growth rate decreases. Dendrites of the primary solidification phase, (Sr1−xCax)14Cu24Oy, form in a matrix of Bi2.5Sr2CaCu2.2Oy when G/R is somewhat less than 3 ⊠ 1011 K-s/m2. Observed microstructures are consistent with a peritectic relationship among Bi2.5Sr2CaCu2.2Oy, (Sr1−xCax)14Cu24Oy (x = 0.4), and a liquid rich in bismuth at elevated oxygen pressure. At lower values of G/R, Sr3Ca2Cu5Oy is the primary solidification phase and negligible Bi2.5Sr2CaCu2.2Oy forms in the matrix.

scholarly journals COMPATIBILITY OF NEUTRAL DETERGENT WITH THE ENTOMOPATHOGENIC FUNGUS METARHIZIUM ANISOPLIAE (METSCH.) SOROK.

2011 ◽  
Vol 78 (3) ◽  
pp. 471-474
Author(s):  
E.S. Harterreiten-Souza ◽  
L.G.A. Pessoa ◽  
E. de S. Loureiro
Keyword(s):  
Entomopathogenic Fungi ◽  
Metarhizium Anisopliae ◽  
Vegetative Growth ◽  
Entomopathogenic Fungus ◽  
Tween 80 ◽  
Genetic Composition ◽  
Fungus Species ◽  
Hydrophobic Character ◽  
Colony Forming Units ◽  
Conidia Production

ABSTRACT Entomopathogenic fungi have been widely used in pests control. The main diluent for its application in the field is water, and due to its hydrophobic character, its dispersion in the environment is complicated. Several products may be mixed to the sprays, allowing the dissolution and the dispersion of the fungus in the spray. Yet, some of these products may influence in the viability, sporulation or even in its genetic composition, changing its virulence. This paper aimed to evaluate the effect of a neutral detergent about the viability of the entomopathogenic fungus Metarhizium anisopliae. Three different concentrations of a neutral detergent (Ipê®) were used: 0.01%, 0.02%, 0.03% and an adhesive spreader (Tween 80) was used in the control. The percentage of conidia germination, the number of colony forming units (CFU), vegetative growth and the number of produced conidia were evaluated. There was no effect of the different concentrations of the neutral detergent on the germination. All detergent concentrations affected negatively in the vegetative growth of the fungus. Only the detergent at 0.01% of concentration did not affect the CFU number and the conidia production of the fungus. So, this is the only concentration classified as compatible for M. anisopliae, which may be recommended to promote the conidia dispersion of this fungus species in water.

Are Growth Parameters Estimated from Tagging and Age–Length Data Comparable?

1988 ◽  
Vol 45 (6) ◽  
pp. 936-942 ◽  
Author(s):  
R. I. C. C. Francis
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Growth Parameters ◽  
Growth Models ◽  
Maximum Length ◽  
Fish Growth ◽  
Data Sets ◽  
Von Bertalanffy ◽  
Length Data ◽  
The Mean

The two most common ways of estimating fish growth use age–length data and tagging data. It is shown that growth parameters estimated from these two types of data have different meanings and thus are not directly comparable. In particular, the von Bertalanffy parameter l∞ means asymptotic mean length at age for age–length data, and maximum length for tagging data, when estimated by conventional methods. New parameterizations are given for the von Bertalanffy equation which avoid this ambiguity and better represent the growth information in the two types of data. The comparison between growth estimates from these data sets is shown to be equivalent to comparing the mean growth rate of fish of a given age with that of fish of length equal to the mean length at that age. How much these growth rates may differ in real populations remains unresolved: estimates for two species of fish produced markedly different results, neither of which could be reproduced using growth models. Existing growth models are shown to be inadequate to answer this question.

Selected growth parameters of farm-raised mallard (Anas platyrhynchos L.) ducklings

2016 ◽  
Vol 96 (4) ◽  
pp. 504-511 ◽  
Author(s):  
Daria Murawska ◽  
Vladimir Hanzal ◽  
Pawel Janiszewski ◽  
Barry D. Lambert ◽  
Michal Gesek ◽  
...  
Keyword(s):  
Growth Rate ◽  
Body Weight ◽  
Growth Rates ◽  
Growth Parameters ◽  
Anas Platyrhynchos ◽  
Carcass Weight ◽  
Muscle Groups ◽  
Breast Weight ◽  
Average Body ◽  
Average Body Weight

The aim of this study was to determine changes in selected growth parameters of farm-raised mallard ducklings from hatch to 42 d of age. The largest increases in body and carcass weights of ducklings and weights of the analyzed tissue components were noted during the first 28 d of the rearing period, except for breast and wing muscles. In comparison with other muscle groups, the growth rate of breast and wing muscles was lower from hatch to 14 d of age, greatest between 14 and 28 d, and remained high up to 42 d of age. The average body weight of mallard ducklings increased more than 16-fold (from 39.7 to 644.8 g, P ≤ 0.01), and the average carcass weight increased more than 26-fold (from 14.4 to 384.5 g, P ≤ 0.01). The growth rates of carcass and tissue components varied considerably. Wing weight increased 84.5-fold (from 0.80 to 67.6 g, P ≤ 0.01), followed by breast weight, which increased 48-fold (from 1.7 to 82.9 g, P ≤ 0.01). Slower growth rates were noted in the remaining carcass parts: back, 23-fold; neck, 19.2-fold; and legs, 17.1-fold (from 5.4 to 92.2 g, P ≤ 0.01).

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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