Embryo Development and Egg Hatching of Sitona crinitus Herbst (Coleoptera: Curculionidae) under Constant Temperature Regimes

2004 ◽  
Vol 7 (7) ◽  
pp. 1191-1193 ◽  
Author(s):  
M. El Damir ◽  
M. El Bouhssini . ◽  
M.N. Al-Salty .
Keyword(s):  
Embryo Development ◽  
Constant Temperature ◽  
Egg Hatching ◽  
Temperature Regimes

scholarly journals Assessing the role of two populations of Aedes japonicus japonicus for Zika virus transmission under a constant and a fluctuating temperature regime

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Uros Glavinic ◽  
Jasmin Varga ◽  
Anca Ioana Paslaru ◽  
Jeannine Hauri ◽  
Paul Torgerson ◽  
...  
Keyword(s):  
Constant Temperature ◽  
Temperature Regime ◽  
Zika Virus ◽  
Incubation Temperature ◽  
Transmission Rate ◽  
Control Measures ◽  
Fluctuating Temperature ◽  
Laboratory Conditions ◽  
Temperature Regimes ◽  
Two Populations

Abstract Background Since the huge epidemic of Zika virus (ZIKV) in Brazil in 2015, questions were raised to understand which mosquito species could transmit the virus. Aedes aegypti has been described as the main vector. However, other Aedes species (e.g. Ae. albopictus and Ae. japonicus) proven to be competent for other flaviviruses (e.g. West Nile, dengue and yellow fever), have been described as potential vectors for ZIKV under laboratory conditions. One of these, the Asian bush mosquito, Ae. japonicus, is widely distributed with high abundances in central-western Europe. In the present study, infection, dissemination and transmission rates of ZIKV (Dak84 strain) in two populations of Ae. japonicus from Switzerland (Zürich) and France (Steinbach, Haut-Rhin) were investigated under constant (27 °C) and fluctuating (14–27 °C, mean 23 °C) temperature regimes. Results The two populations were each able to transmit ZIKV under both temperature regimes. Infectious virus particles were detected in the saliva of females from both populations, regardless of the incubation temperature regime, from 7 days post-exposure to infectious rabbit blood. The highest amount of plaque forming units (PFU) (400/ml) were recorded 14 days post-oral infection in the Swiss population incubated at a constant temperature. No difference in terms of infection, dissemination and transmission rate were found between mosquito populations. Temperature had no effect on infection rate but the fluctuating temperature regime resulted in higher dissemination rates compared to constant temperature, regardless of the population. Finally, transmission efficiency ranged between 7–23% and 7–10% for the constant temperature and 0–10% and 3–27% under fluctuating temperatures for the Swiss and the French populations, respectively. Conclusions To the best of our knowledge, this is the first study confirming vector competence for ZIKV of Ae. japonicus originating from Switzerland and France at realistic summer temperatures under laboratory conditions. Considering the continuous spread of this species in the northern part of Europe and its adaptation at cooler temperatures, preventative control measures should be adopted to prevent possible ZIKV epidemics.

Germination of Seeds of Perennial Pepperweed (Lepidium latifolium)

Weed Science ◽  
1986 ◽  
Vol 34 (2) ◽  
pp. 252-255 ◽  
Author(s):  
Gerald K. Miller ◽  
James A. Young ◽  
Raymond A. Evans
Keyword(s):  
United States ◽  
Constant Temperature ◽  
Western United States ◽  
Lepidium Latifolium ◽  
Temperature Regimes ◽  
Riparian Habitats ◽  
Alternating Temperature

Perennial pepperweed (Lepidium latifoliumL. # LEPLA) is a serious weed of meadows and riparian habitats in the intermountain area of the western United States. Germination of seeds of this species was tested at 55 constant- and alternating-temperature regimes. No significant differences were found in mean germination at a range of temperatures varying from 0 to 40 C for seedlots collected at the same site in different years or at different locations in the same year. Optimum germination not significantly (P = 0.01) lower than the maximum observed occurred most frequently at 5/40 C (5 C for 16 h and 40 C for 8 h), and 10/40 and 15/40 C. Germination was enhanced by alternating regimes with low night temperatures (0, 2, or 5 C) and high day temperatures (35 and 40 C), in comparison with more moderate constant-temperature regimes.

scholarly journals CONSTANT TEMPERATURE AND TIME PERIOD EFFECTS ON ANOPHELES GAMBIAE EGG HATCHING

2007 ◽  
Vol 23 (2) ◽  
pp. 124-130 ◽  
Author(s):  
DANIEL E. IMPOINVIL ◽  
GABRIEL A. CARDENAS ◽  
JOHN I. GIHTURE ◽  
CHARLES M. MBOGO ◽  
JOHN C. BEIER
Keyword(s):  
Anopheles Gambiae ◽  
Constant Temperature ◽  
Egg Hatching ◽  
Period Effects ◽  
Time Period

Effects of Low Environmental pH on Smolting of Atlantic Salmon (Salmo salar)

1983 ◽  
Vol 40 (8) ◽  
pp. 1203-1211 ◽  
Author(s):  
Richard L. Saunders ◽  
Eugene B. Henderson ◽  
Paul R. Harmon ◽  
C. Edward Johnston ◽  
J. Geoffrey Eales
Keyword(s):  
Atlantic Salmon ◽  
Atpase Activity ◽  
Salmo Salar ◽  
Constant Temperature ◽  
Water Hardness ◽  
Low Ph ◽  
Temperature Plasma ◽  
Atlantic Salmon Salmo Salar ◽  
Temperature Regimes ◽  
And Control

We reared Atlantic salmon (Salmo salar) in soft water (hardness 13 mg/L as CaCO3) at two pH levels, 6.4–6.7 and 4.2–4.7, from February to June, to assess the effect of low pH on survival, growth, and the smolting process under rising (4–8.5 °C) or relatively constant (9.5–10.5 °C) temperature. Survival was lower as a result of low pH (4.2–4.7) under both temperature regimes. Neither group exposed to low pH gained weight whereas both control groups gained weight during the experiment. Parr–smolt transformation, as indicated by salinity tolerance and gill Na+, K+ ATPase activity, was impaired as a result of low pH. The large (17–19 cm) parr used in this study were initially salinity tolerant and those at control pH (6.4–6.7) increased tolerance to 35‰ salinity between March and May; those in low pH became intolerant of high salinity. ATPase levels in salmon reared at low pH were significantly lower than those at normal pH levels under both temperature regimes. ATPase activity was significantly greater in fish reared at pH 6.4–6.7 with rising than with constant temperature. Plasma chloride and sodium levels were low in response to low pH, indicating impaired ionic regulation in freshwater. Plasma calcium levels were higher at low pH in both temperature regimes; higher levels were reached under constant temperature. Moisture content rose less sharply under low than under control pH in both temperature regimes. In the rising temperature regime, lipid levels reached similar, low levels under low and control pH conditions. Thyroid hormone (T3 and T4) levels gave no clear indication of effects of low pH on smolting. Smoltification did not proceed normally in our Atlantic salmon subjected to low pH levels.

scholarly journals EFFECT OF PHOTOPERIOD AND TEMPERATURE REGIMES ON YIELD OF SWEET POTATOES GROWN USING THE NUTRIENT FILM TECHNIQUE (NFT)

HortScience ◽  
1990 ◽  
Vol 25 (8) ◽  
pp. 858g-858
Author(s):  
Desmond Mortley ◽  
Conrad Bonsi ◽  
Philip Loretan ◽  
Walter Hill ◽  
Edwin Martinez
Keyword(s):  
Sweet Potato ◽  
Constant Temperature ◽  
Continuous Light ◽  
Storage Root ◽  
Sweet Potatoes ◽  
Root Numbers ◽  
Temperature Regimes ◽  
Nutrient Film Technique ◽  
Growth Chambers ◽  
Hoagland Nutrient Solution

Hydroponic experiments using the nutrient film technique (NFT) were conducted in environmental growth chambers to evaluate the response of two sweet potato cultivars, `Georgia Jet' and `TI-155', to two photoperiod and temperature regimes. Vine cuttings of these cultivars were planted in growth channels supplied with modified half-Hoagland nutrient solution using NFT. Plants were subjected to a 24 h photoperiod or a 12:12 h light:dark photoperiod, a constant temperature of 28C or light:dark temperature of 28/22C. Plants were exposed to irradiance levels of 400 umol m-2 s-1 at canopy level and 70% RH. Storage root fresh and dry weights were increased for both cultivars under the 24 h photoperiod at the 28C constant temperature. `Georgia Jet' storage root numbers were not affected by any treatment while those for `TI-155' were reduced under continuous light for both temperature regimes. Foliage fresh and dry weights were not affected by any treatment.

scholarly journals Assessing the role of two populations of Aedes japonicus japonicus for Zika virus transmission under a constant and a fluctuating temperature regime.

2020 ◽  
Author(s):  
Uros Glavinic ◽  
Jasmin Varga ◽  
Anca Iona Paslaru ◽  
Jeannine Hauri ◽  
Paul Torgerson ◽  
...  
Keyword(s):  
Constant Temperature ◽  
Temperature Regime ◽  
Zika Virus ◽  
Incubation Temperature ◽  
Transmission Rate ◽  
Control Measures ◽  
Fluctuating Temperature ◽  
Laboratory Conditions ◽  
Temperature Regimes ◽  
Two Populations

Abstract Background Since the huge epidemic of Zika virus (ZIKV) in Brazil in 2015, questions were raised to understand which mosquito species could transmit the virus. Aedes aegypti has been described as the main vector. However, other Aedes species (e.g. Ae. albopictus and Ae. japonicus) proven to be competent for other Flaviviruses (e.g.West Nile, dengue and yellow fever), have been described as potential vector for ZIKV under laboratory conditions. To name one, the Asian bush mosquito Ae. japonicus which is widely distributed with high abundances in Central-Western Europe. In the present study, infection, dissemination and transmission rates of ZIKV (Dak84 strain) in two populations of Ae. japonicus from Switzerland (Zürich) and France (Steinbach, Haut-Rhin) were investigated under constant (27 °C) and fluctuating (14-27 °C, mean 23 °C) temperature regimes.Results The two populations were each able to transmit ZIKV under both temperature regimes. Infectious virus particles were detected in the saliva of females from both populations, regardless of the incubation temperature regime, from 7 days post exposure to infectious rabbit blood. The highest amount of Plaque Forming Unit (PFU) (400/ml) were recorded 14 days post oral infection in the Swiss population incubated at constant temperature. No difference in term of infection, dissemination and transmission rate were found between mosquito populations.Temperature had no effect on infection rate but the fluctuating temperature regime resulted in higher dissemination rates comparing to constant temperature, regardless of the population. Finally, transmission efficiency ranged between 7-23% and 7-10% for the constant temperature and 0-10% and 3-27% under fluctuating temperatures for the Swiss and the French populations, respectively.Conclusions This is the first work confirming vector competence for ZIKV of Ae. japonicus originating from Switzerland and France at realistic summer temperatures under laboratory conditions. Considering the continuous spread of this species in the northern part of Europe and its adaptation at cooler temperatures, preventative control measures should be adopted to prevent possible ZIKV epidemics.

scholarly journals Some details and effects of the premeiotic controls of recombination frequencies in Neurospora crossa

1971 ◽  
Vol 18 (3) ◽  
pp. 255-264 ◽  
Author(s):  
B. C. Lamb
Keyword(s):  
Constant Temperature ◽  
Mating Type ◽  
Meiotic Recombination ◽  
Vegetative Growth ◽  
Adaptive Significance ◽  
Opposite Mating Type ◽  
Reciprocal Crosses ◽  
Temperature Regimes ◽  
Single Constant ◽  
Made In

SUMMARYRecombination data from crosses made at a single constant temperature of incubation were compared with those from crosses transferred to a different temperature at either the time of conidiation of protoperithecia by the strain of opposite mating-type, or after fertilization when crozier stages were first visible. Results were also compared from reciprocal crosses, from crosses made in different ways and from crosses in which protoperithecia were conidiated at different stages of maturity.Different temperature regimes during vegetative growth and proto-perithecial development had highly significant effects on subsequent meiotic recombination, while temperature differences during later premeiotic stages (between conidiation of protoperithecia and the crozier stage) had no or little effect. It was found that premeiotic controls could have as great, or greater, effects on meiotic recombination than those operating directly during meiosis. The possible adaptive significance of this is discussed.Recombination frequencies were affected by the method of making a cross (joint-inoculation of strains of opposite mating-type, or conidiation of protoperithecia), and by protoperithecial age at the time of conidiation by the opposite mating-type. Differences in recombination between reciprocal crosses were obtained and were dependent on temperature of incubation and age of protoperithecia at the time of conidiation. Recombination was not affected by different lysine concentrations in the medium. Genetic differences in premeiotic effector-production between the strains used were inferred.

Germination of leafy spurge (Euphorbia esula L.) seeds under alternating temperatures: the effects of amplitude, midpoint, and imbibition in gibberellic acid

2016 ◽  
Vol 96 (3) ◽  
pp. 321-328
Author(s):  
Michael E. Foley
Keyword(s):  
Gibberellic Acid ◽  
Constant Temperature ◽  
Temperature Regime ◽  
Initial Temperature ◽  
Leafy Spurge ◽  
Euphorbia Esula ◽  
Amplitude Difference ◽  
Temperature Regimes ◽  
Alternating Temperature

Germinability of dormant seeds or the capacity to germinate under particular conditions is sometimes enhanced by a diurnal alternating temperature regime relative to a constant temperature. Alternating temperature regimes vary in amplitude (difference between the minimum and maximum) and midpoint (average). The aim of this research was to test the effects of amplitude and midpoint regimes on germination of dormant leafy spurge seed from a Fargo, ND population in water and gibberellic acid (GA3). The optimal regimes for germination in both water and GA3 were 20:30 °C (16 h:8 h) and 20:35 °C (19 h:5 h), which provided amplitudes of 10 °C and 15 °C, respectively, with both conditions having a midpoint temperature of 23.3 °C. However, midpoint temperature of 22 °C to 27 °C were equally effective for germination under the 20:30 °C and 20:35 °C alternating temperature regimes. Additional alternating temperature regimes with amplitudes of 15 °C (15:30 °C and 10:25 °C), 20 °C (10:30 °C), and 25 °C (10:35 °C) generally displayed reduced germination in both water and GA3, which is likely attributable to the low initial alternating temperature (≤15 °C) component of the regime relative to the higher initial temperature of 20 °C for the optimum regimes of 20:30 °C and 20:35 °C. Under the alternating temperature regimes tested, seeds germinated in GA3 generally displayed higher germination (≥80%) compared with seeds in water (30%–50%).

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