Thermal Sensitivity ofDrosophila melanogaster:Evolutionary Responses of Adults and Eggs to Laboratory Natural Selection at Different Temperatures

1997 ◽  
Vol 70 (4) ◽  
pp. 403-414 ◽  
Author(s):  
George W. Gilchrist ◽  
Raymond B. Huey ◽  
Linda Partridge
Author(s):  
Alan S. Lima ◽  
Letícia de F. Ferreira ◽  
Diego P. Silva ◽  
Fernando R. Gomes ◽  
Stefanny C. M. Titon

2021 ◽  
Vol 9 ◽  
Author(s):  
Antoni Gayà ◽  
Massimo Rittà ◽  
David Lembo ◽  
Paola Tonetto ◽  
Francesco Cresi ◽  
...  

One of the main concerns in human milk banks (HMB) is the transmission of human cytomegalovirus (HCMV) that could be present in the milk of infected women. There are consistent data showing that this virus is destroyed by Holder pasteurization (62.5°C for 30 min), but there is a lack of information about the response of the virus to the treatment at lower temperatures in strict HMB conditions. In order to analyze the effectiveness of different temperatures of pasteurization to eliminate HCMV in human milk, a preliminary assay was performed incubating HCMV-spiked raw milk samples from donor mothers at tested temperatures in a PCR thermocycler and the viral infectivity was assayed on cell cultures. No signs of viral replication were observed after treatments at temperatures equal or >53°C for 30, 20, and 10 min, 58°C for 5 min, 59°C for 2 min, and 60°C for 1 min. These data were confirmed in a pasteurizer-like model introducing HCMV-spiked milk in disposable baby bottles. No viral infectivity was detected on cell cultures after heating treatment of milk for 30 min at temperatures from 56 to 60°C. Thus, our results show that by using conventional pasteurization conditions, temperatures in the range of 56–60°C are enough to inactivate HCMV. Consequently, we consider that, in order to provide a higher quality product, the current recommendation to pasteurize both mother's own milk and donated milk at 62.5°C must be re-evaluated.


2020 ◽  
Vol 116 (2) ◽  
pp. 245
Author(s):  
Hassan ABHARI ◽  
Amir Hossein ELHAMI RAD ◽  
Hojjat KARAZHIYAN ◽  
Abbas ABHARI

<p>Grape molasses is a traditional sweet with high nutritional value. One factor limiting the production and storage of grape molasse halva Gazi is related to the thermal sensitivity of its texture properties and decreasing its quality during storage at ambient temperature. Therefore, this study aimed to improve the texture properties of the newly formulated halva during storage at different temperatures. Different levels of gums (0.5 %, 1 % &amp; 1.5 %) including alginate, carrageenan, xanthan, and their blends (0.5 %-0.5 %) were used as additives in the formulation of halva to improve its texture during 48 h storage at 25 °C and 40 °C. The texture analysis tests were then performed to evaluate the firmness and fracturability of the halva. The results showed that the combination of gums, as well as using xanthan gum alone, produced an appropriate and soft texture in comparison to the control halva (0 % gum). However, the halva containing carrageenan-alginate blends showed the softest texture. The samples containing 0.5 and 1 % of alginate and xanthan as well as xanthan-alginate blend and xanthan-carrageenan blend had the best texture properties during storage at 40 °C.</p>


Evolution ◽  
1991 ◽  
Vol 45 (3) ◽  
pp. 751-756 ◽  
Author(s):  
Raymond B. Huey ◽  
Linda Partridge ◽  
Kevin Fowler

1988 ◽  
Vol 101 (2) ◽  
pp. 321-325 ◽  
Author(s):  
Z. Hubálek ◽  
J. Halouzka

SUMMARYA sterile suspension containing 950 mouse LD50 per ml of type C botulinum toxin was exposed for various periods to different temperatures. The time required for the 99% (hundred-fold) reduction of toxicity was more than 5 years at -70°C or -20°C, 6 montha at +5 °C, 3 weeks at +20 °C, 2 weeks at +28 °C, 2 days at +37 °C, 9h at +42°C, less than 30 min at 56 °C, less than 20 min at +60 °C, and below 5 min at +80 °C. The results suggest thatClostridium botulinumtype C toxin, if produced in an ecosystem of the mild climatic zone, might persist there over the winter season and cause the intoxication of vertebrates next carly spring in the absence of further microbial toxigenesis.


2017 ◽  
Author(s):  
Leonardo D. Bacigalupe ◽  
Juan D. Gaitan-Espitia ◽  
Aura M. Barria ◽  
Avia Gonzalez-Mendez ◽  
Manuel Ruiz-Aravena ◽  
...  

AbstractThis preprint has been reviewed and recommended by Peer Community In Evolutionary Biology (http://dx.doi.org/10.24072/pci.evolbiol.100048). For ectothermic species with broad geographical distributions, latitudinal/altitudinal variation in environmental temperatures (averages and extremes) are expected to shape the evolution of physiological tolerances and the acclimation capacity (i.e., degree of phenotypic plasticity) of natural populations. This can create geographical gradients of selection in which environments with greater thermal variability (e.g., seasonality) tend to favour individuals that maximize performance across a broader range of temperatures compared to more stable environments. Although thermal acclimation capacity plays a fundamental role in this context, it is unknown whether natural selection targets this trait in natural populations. Here we addressed such an important gap in our knowledge by measuring survival, through mark recapture integrated into an information-theoretic approach, as a function of the plasticity of critical thermal limits for activity, behavioural thermal preference and the thermal sensitivity of metabolism in the northernmost population of the four-eyed frogPleurodema thaul. Overall, our results indicate that thermal acclimation in this population is not being targeted by directional selection, although there might be signals of selection on individual traits. According to the most supported models, survival decreased in individuals with less tolerance to cold when cold-acclimated (probably because daily low extremes are frequent during the cooler periods of the year) and increased with body size. However, in both cases, the directional selection estimates were non-significant.


Evolution ◽  
1991 ◽  
Vol 45 (3) ◽  
pp. 751 ◽  
Author(s):  
Raymond B. Huey ◽  
Linda Patridge ◽  
Kevin Fowler

1973 ◽  
Vol 51 (6) ◽  
pp. 1191-1196 ◽  
Author(s):  
Dempsey L. Thomas ◽  
James E. Bright

Protein extracts from dormant peanut cotyledons were heated to determine the influence of different temperatures on banding characteristics of soluble proteins and enzymes by use of horizontal starch gel electrophoresis. Soluble proteins showed no significant change between 25° and 85 °C. At 95 °C, however, major bands of reserve protein decreased in staining intensity and new bands with greater migration velocity appeared; banding still occurred at 100 °C. Distribution patterns of glutamate dehydrogenase (GDH), malate dehydrogenase (MDH), nonspecific α-esterases (α-EST), and leucine aminopeptidase (LAP) reflected no change in banding or apparent enzyme activity at temperatures less than 45 °C. Complete inactivation was estimated for GDH at 80 to 85 °C, MDH at 65 °C, α-EST at 60 to 65 °C, and LAP at 60 to 65 °C. Isoenzymes of GDH, MDH, and LAP, and bands of α-EST exhibited differential thermal sensitivity. Peroxidase activity (using pyrogallol as the hydrogen donor) was not influenced through 65 °C; minimal reaction with benzidine occurred. No alkaline phosphatase activity was observed. Banding patterns of proteins or enzymes heated for 15 min were identical with those heated for 30 min. The results are compared with those of other studies regarding the influence of heat on proteins and enzymes in extracts of heated cotyledons from 5-day peanut seedlings and in extracts from wet- and dry-roasted seed.


2021 ◽  
Vol 15 ◽  
Author(s):  
Lola Rueda-Ruzafa ◽  
Salvador Herrera-Pérez ◽  
Ana Campos-Ríos ◽  
J. A. Lamas

Internal human body normal temperature fluctuates between 36.5 and 37.5°C and it is generally measured in the oral cavity. Interestingly, most electrophysiological studies on the functioning of ion channels and their role in neuronal behavior are carried out at room temperature, which usually oscillates between 22 and 24°C, even when thermosensitive channels are studied. We very often forget that if the core of the body reached that temperature, the probability of death from cardiorespiratory arrest would be extremely high. Does this mean that we are studying ion channels in dying neurons? Thousands of electrophysiological experiments carried out at these low temperatures suggest that most neurons tolerate this aggression quite well, at least for the duration of the experiments. This also seems to happen with ion channels, although studies at different temperatures indicate large changes in both, neuron and channel behavior. It is known that many chemical, physical and therefore physiological processes, depend to a great extent on body temperature. Temperature clearly affects the kinetics of numerous events such as chemical reactions or conformational changes in proteins but, what if these proteins constitute ion channels and these channels are specifically designed to detect changes in temperature? In this review, we discuss the importance of the potassium channels of the TREK subfamily, belonging to the recently discovered family of two-pore domain channels, in the transduction of thermal sensitivity in different cell types.


Author(s):  
J. L. Brimhall ◽  
H. E. Kissinger ◽  
B. Mastel

Some information on the size and density of voids that develop in several high purity metals and alloys during irradiation with neutrons at elevated temperatures has been reported as a function of irradiation parameters. An area of particular interest is the nucleation and early growth stage of voids. It is the purpose of this paper to describe the microstructure in high purity nickel after irradiation to a very low but constant neutron exposure at three different temperatures.Annealed specimens of 99-997% pure nickel in the form of foils 75μ thick were irradiated in a capsule to a total fluence of 2.2 × 1019 n/cm2 (E > 1.0 MeV). The capsule consisted of three temperature zones maintained by heaters and monitored by thermocouples at 350, 400, and 450°C, respectively. The temperature was automatically dropped to 60°C while the reactor was down.


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