Effect of temperature on subclinical infection by Batrachochytrium dendrobatidis in three species of plethodontid salamanders

2021 ◽  
pp. 1-7
Author(s):  
Cinthya Mendoza-Almeralla ◽  
Ireri Suazo-Ortuño ◽  
Gabriela Parra-Olea ◽  
Gerardo Suzán

Abstract We assessed the effect of temperature on subclinical Batrachochytrium dendrobatidis (Bd) infection in three species of plethodontids. Collected individuals were tested for Bd in the field during the dry and rainy season and randomly assigned to 15° and 18°C treatments for 30 days. We collected 129 salamanders, of these nine individuals tested positive for Bd in the field. At the two temperature trials, 12 individuals that were Bd-negative in the field, tested positive for Bd. Near the end of the temperature trials, 18 of 21 Bd-positive individuals tested negative for Bd. Three individuals that were Bd positive in the field and assigned to the 18°C trial died during the experiment. Our results suggest that at 15°C the most of plethodontids present subclinical infection, whereas at higher temperatures, Bd infection can increase to detectable levels. The processes underlying plethodontids’s recovery from Bd infection warrants further study.

2017 ◽  
Vol 13 (11) ◽  
pp. 1515-1526 ◽  
Author(s):  
Aliénor Lavergne ◽  
Fabio Gennaretti ◽  
Camille Risi ◽  
Valérie Daux ◽  
Etienne Boucher ◽  
...  

Abstract. Oxygen isotopes in tree rings (δ18OTR) are widely used to reconstruct past climates. However, the complexity of climatic and biological processes controlling isotopic fractionation is not yet fully understood. Here, we use the MAIDENiso model to decipher the variability in δ18OTR of two temperature-sensitive species of relevant palaeoclimatological interest (Picea mariana and Nothofagus pumilio) and growing at cold high latitudes in North and South America. In this first modelling study on δ18OTR values in both northeastern Canada (53.86° N) and western Argentina (41.10° S), we specifically aim at (1) evaluating the predictive skill of MAIDENiso to simulate δ18OTR values, (2) identifying the physical processes controlling δ18OTR by mechanistic modelling and (3) defining the origin of the temperature signal recorded in the two species. Although the linear regression models used here to predict daily δ18O of precipitation (δ18OP) may need to be improved in the future, the resulting daily δ18OP values adequately reproduce observed (from weather stations) and simulated (by global circulation model) δ18OP series. The δ18OTR values of the two species are correctly simulated using the δ18OP estimation as MAIDENiso input, although some offset in mean δ18OTR levels is observed for the South American site. For both species, the variability in δ18OTR series is primarily linked to the effect of temperature on isotopic enrichment of the leaf water. We show that MAIDENiso is a powerful tool for investigating isotopic fractionation processes but that the lack of a denser isotope-enabled monitoring network recording oxygen fractionation in the soil–vegetation–atmosphere compartments limits our capacity to decipher the processes at play. This study proves that the eco-physiological modelling of δ18OTR values is necessary to interpret the recorded climate signal more reliably.


Development ◽  
1971 ◽  
Vol 25 (3) ◽  
pp. 339-345
Author(s):  
Jean Piatt

Eggs of Ambystoma maculatum in early stages of development were separated into two groups and maintained at 5 and 14 °C, respectively. In one series of animals comprising both temperature groups, the right otic vesicle was extirpated at stage 27. In another series the right forelimb disc was extirpated at stage 30. Following operation, animals of both groups were kept at 18 °C. Frequency and extent of reconstitution were compared between the two temperature groups. The 5° group was superior to the 14° group in the number of ears and forelimbs reconstituted. The extent of ear reconstitution and the initial quality of forelimb reconstitution were also superior in the 5° group. Statistical analysis of the data indicates that the difference between the two temperature groups is highly significant in both series. It is concluded that a slower pre-operative rate of development, caused by hypothermia, enhances the regenerative capacity of both ear and forelimb fields in the salamander embryo.


2017 ◽  
Vol 05 (03) ◽  
pp. 1750008 ◽  
Author(s):  
Ashraf M. Zenkour ◽  
Ahmed E. Abouelregal

A two-temperature theory of the generalized thermoelasticity is proposed to study the effect of temperature dependence on a semi-infinite medium. The surface of bounding plane of the medium is under a non-Gaussian laser pulse. Lamé’s coefficients and the thermal conductivity are supposed as temperature-dependent linear functions. The dual-phase-lags (DPLs) theory of the generalized thermoelasticity is applied to treat with the present problem. The analytical solution for different boundary conditions may be deduced by using Laplace transform technique. The numerical results are obtained by using the inverse of Laplace transforms. The comparisons have been graphically presented to show the effects of PLs, temperature discrepancy, laser pulse and laser intensity parameters on field quantities. Also, the results are compared with those obtained from the mechanical and thermal material properties with the temperature independence.


1979 ◽  
Vol 29 (3) ◽  
pp. 423-426 ◽  
Author(s):  
K. J. McCracken ◽  
B. J. Caldwell ◽  
N. Walker

ABSTRACTTwo temperature regimes were compared in relation to the growth and feed conversion ratio of groups of cage-reared pigs between 10 and 38 days of age. The treatments were: 27°C at 10 days reducing by 1°C every 4 days to 20°C at 38 days; and 27°C at 10 days reducing by 1°C daily to 20°C at 17 days and then remaining constant. Twelve replicates using 244 pigs were completed, the group size varying between 9 and 12 pigs. The mean growth rates on the two temperature regimes were respectively 234 and 243 g/day, and in both cases feed conversion ratio (kg DM/kg gain) averaged 1·03. It is concluded that temperatures lower than those currently recommended for pigs weaned at 14 to 16 days into controlled-environment houses would support satisfactory performance with direct savings in heating costs under winter conditions.


2017 ◽  
Author(s):  
Aliénor Lavergne ◽  
Fabio Gennaretti ◽  
Camille Risi ◽  
Valérie Daux ◽  
Etienne Boucher ◽  
...  

Abstract. Oxygen isotopes in tree-rings (δ18OTR) are widely used to reconstruct past climates. However, the complexity of climatic and biological processes controlling isotopic fractionation is not yet fully understood. Here, we use the MAIDENiso model to decipher the variability of δ18OTR of two temperature-sensitive species of relevant paleoclimatological interest (Picea mariana and Nothofagus pumilio) and growing at cold high-latitudes in North and South America. In this first modelling study on δ18OTR values in both northeastern Canada (53.86° N) and western Argentina (41.10° S), we specifically aim at: (1) evaluating the predictive skill of MAIDENiso to simulate δ18OTR values, (2) identifying the physical processes controlling δ18OTR by mechanistic modelling and, (3) defining the origin of the temperature signal recorded in the two species. Although the linear regression models used here to predict daily δ18O of precipitation (δ18OP) may need to be improved in the future, the resulting daily δ18OP values adequately reproduce observed (from weather stations) and simulated (by global circulation model) δ18OP series. The δ18OTR values of the two species are correctly simulated using the δ18OP estimation as MAIDENiso input, although some offset in mean δ18OTR levels is observed for the South American site. For both species, the variability of δ18OTR series is more likely linked to the effect of temperature on isotopic enrichment of the leaf water rather than on the isotopic composition of the source water. We show that MAIDENiso is a powerful tool for investigating isotopic fractionation processes but that the lack of a denser isotope-enabled monitoring network recording oxygen fractionation in the soil-vegetation-atmosphere compartments limits our capacity to decipher the processes at play. This study proves that the eco-physiological modelling of δ18OTR values is necessary to interpret the recorded climate signal more reliably.


Plants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 843
Author(s):  
Cunchun Yang ◽  
Zhongwei Zou ◽  
Wannakuwattewaduge Gerard Dilantha Fernando

Temperature is considered one of the crucial environmental elements in plant pathological interactions, and previous studies have indicated that there is a relationship between temperature change and host–pathogen interactions. The objective of this research is to investigate the link between temperature and the incompatible interactions of the host and pathogen. In this study, two Leptosphaeria maculans isolates (HCRT75 8-1 and HCRT77 7-2) and two Brassica napus genotypes (Surpass400 and 01-23-2-1) were selected. The selected B. napus genotypes displayed intermediate and resistant phenotypes. The inoculated seedlings were tested under three temperature conditions: 16 °C/10 °C, 22 °C/16 °C and 28 °C/22 °C (day/night: 16 h/8 h). Lesion measurements demonstrated that the necrotic lesions from the 28 °C/22 °C treatment were enlarged compared with the other two temperature treatments (i.e., 16 °C/10 °C and 22 °C/16 °C). The results of expression analysis indicated that the three temperature treatments displayed distinct differences in two marker genes (PATHOGENESIS–RELATED (PR) 1 and 2) for plant defense and one temperature-sensitive gene BONZAI 1 (BON1). Additionally, seven dpi at 22 °C/16 °C appeared to be the optimal pre-condition for the induction of PR1 and 2. These findings suggest that B. napus responds to temperature changes when infected with L. maculans.


1927 ◽  
Vol 10 (6) ◽  
pp. 961-985 ◽  
Author(s):  
Vladimir Pertzoff

1. The investigations dealing with the properties of casein as an acid were reviewed. 2. The solubility of uncombined casein in water was measured at 5°C. and found to be 0.70±0.1 mg. of N per 100 gm. of water. 3. Robertson's solubility measurements of casein in bases at various temperatures were recalculated and found to agree well with more recent measurements. 4. By combining the observations of several investigators, as well as the author's measurements of the solubility of casein, in base, at various temperatures, the following conclusions were reached: (a) The solubility of casein in base is affected by the temperature in a discontinuous manner. (b) There exist two ranges of temperature, one, extending from about 21° to 37°C. and the other from about 60° to 85°C. where the solubility of casein in base is practically independent of temperature. (c) From 37° to 60° the equivalent combining weight of casein rises from the value 2100 to about 3700 gm. 5. By comparing the values of base bound by 1 gm. of casein at the two temperature ranges with a constant, the value of base necessary to saturate the same amount of casein, it was found that the latter value is a common multiple of the former values, indicating the stoichiometric nature of the effect of temperature.


2017 ◽  
Vol 24 (3) ◽  
pp. 443-455
Author(s):  
Krzysztof Gondek ◽  
Agnieszka Baran ◽  
Monika Mierzwa-Hersztek ◽  
Michał Kopeć

Abstract The aim of the research was to evaluate the effect of temperature during the treatment process as well as the effect of adding plant materials to sewage sludge on selected chemical properties and Vibrio fischeri response. The mixtures were placed in a chamber furnace, under airless conditions. Two temperature procedures were applied: 300 and 600ºC; the exposure time in both cases was 15 minutes. Thermal treatment of sewage sludge without a plant component is not well-founded and may cause an increase in concentration of trace elements. Using the temperature of 300ºC caused significantly lower changes in the contents of total forms of trace elements than using the temperature of 600ºC. The metals extracted from the studied mixtures were not toxic for the Vibrio fischeri. In the case of the fractional composition of humic compounds, thermal treatment of mixtures of sewage sludge and plant materials is not beneficial in terms of labile fractions, but it had a beneficial effect on stabilizing the durable bonds between C compounds in those mixtures.


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