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. 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 Unit (PFU) (400/ml) were recorded 14 days post oral infection in the Swiss population incubated at 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 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 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.

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 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 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.

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 ◽  
Western Europe ◽  
Transmission Rate ◽  
Vector Competence ◽  
Mosquito Species ◽  
Control Measures ◽  
Fluctuating Temperature ◽  
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. Although Aedes aegypti has been described as the main vector, other Aedes species (e.g. Ae. albopictus and Ae. japonicus) which can potentially transmit viruses from the same family (Flavivirus) such as West Nile, dengue and yellow fever, at least under laboratory conditions, have been incriminated as potential vector for ZIKV. Among these, the Asian bush mosquito Ae. japonicus is widely spread 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 Both populations were positive for ZIKV transmission. Infectious virus particles were present already 7 days post exposure to infectious rabbit blood. The highest amount of Plaque Forming Unit (PFU) (400/female) 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 according to the mosquito population.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 under realistic summer temperatures. 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.

Fluctuating temperature and light influence seed germination of goosegrass (Eleusine indica)

Weed Science ◽  
1997 ◽  
Vol 45 (3) ◽  
pp. 426-429 ◽  
Author(s):  
Roy K. Nishimoto ◽  
Lambert B. McCarty
Keyword(s):  
Seed Germination ◽  
Temperature Regime ◽  
Fluctuating Temperature ◽  
Eleusine Indica ◽  
Temperature Cycles ◽  
Temperature Regimes ◽  
Moist Environment

This research examined the effect of duration of the warm cycle and number of fluctuating temperature/light cycles on goosegrass seed germination. Less than 10% goosegrass seed germination occurred at constant temperatures of 20, 25, and 35 C, while 99% germinated at daily fluctuating temperature regimes of 20 C for 16 h and 35 C for 8 h with light. Increasing the number of fluctuating temperature cycles increased goosegrass seed germination. Fluctuating temperature cycles with 22 h at 20 C and 2 h at 35 C with light strongly stimulated germination, but not as much as the cycle with 8 h at 35 C. Goosegrass seed germination ceased once the fluctuating temperature regime was discontinued, and constant 20 C with 8 h light daily was reimposed. Germination occurred only on resumption of fluctuating temperature cycles. Seed incubated for several weeks in a moist environment at constant 20 C had 81 to 91% germination with two cycles of 20 C for 16 h and 35 C for 8 h, compared to 14% for fresh seeds.

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%).

Fall condition factor and temperature influence the incidence of metamorphosis in sea lampreys, Petromyzon marinus

1994 ◽  
Vol 72 (6) ◽  
pp. 1134-1140 ◽  
Author(s):  
John A. Holmes ◽  
John H. Youson
Keyword(s):  
Ambient Temperature ◽  
Constant Temperature ◽  
Temperature Regime ◽  
Condition Factor ◽  
Petromyzon Marinus ◽  
Population Differences ◽  
Temperature Influence ◽  
Temperature Regimes ◽  
Sea Lampreys ◽  
Effects Of Temperature

Larval sea lampreys of immediate premetamorphic size (at least 120 mm and 3.0 g) were subjected to ambient or constant 21 °C temperature regimes for 9 months to investigate the influence of temperature and a fall condition factor (CF) of 1.50 or greater on the incidence of metamorphosis the following summer. The incidence of metamorphosis was 53% in the ambient temperature regime (29/55) and only 2% (1/55) in the constant temperature regime. About 64% (7/11) of the presumptively metamorphic larvae in the ambient temperature regime entered metamorphosis compared with 10% (1/10) in the constant temperature regime. Our predictions of metamorphosis based on CF were consistent with the observation that seven presumptively metamorphic larvae (CF ≥ 1.50) metamorphosed in the ambient temperature regime and that there was no metamorphosis among presumptively nonmetamorphic larvae in the constant temperature regime. Significantly more presumptively nonmetamorphic larvae in the ambient regime entered metamorphosis and fewer presumptively metamorphic larvae (CF < 1.50) metamorphosed in the constant temperature regime than expected. We attribute this response to the effects of temperature on metabolic processes. Larval sea lampreys of the appropriate size (≥ 120 mm and ≥ 3.0 g) with a CF of 1.50 or greater in the fall will usually enter metamorphosis the following July, but the accuracy of these predictions may be improved in some populations by using an empirically determined CF criterion that reflects seasonal or population differences in mass–length relationships.

Can alternating temperature, moist chilling, and gibberellin interchangeably promote the completion of germination in Clematis vitalba seeds?

Botany ◽  
2017 ◽  
Vol 95 (8) ◽  
pp. 847-852 ◽  
Author(s):  
Rosangela Picciau ◽  
Marco Porceddu ◽  
Gianluigi Bacchetta
Keyword(s):  
Seed Germination ◽  
Gibberellic Acid ◽  
Plant Species ◽  
Temperature Regime ◽  
Fluctuating Temperature ◽  
Temperature Regimes ◽  
Moist Chilling ◽  
Clematis Vitalba ◽  
Alternating Temperature ◽  
Positive Effect

Each plant species has particular requirements for seed germination, and some of them respond differently to constant or alternating temperature regimes. In this study, the interchangeable effects of different treatments and temperatures on the completion of seed germination of Clematis vitalba L. were investigated. The seeds were tested with a constant (from 5 °C to 25 °C) or a fluctuating (25/10 °C) temperature regime, and the effect of gibberellic acid (GA3), incubation at warm (W) or cold (C) temperatures while being imbibed, and drying after ripening (DAR) were evaluated. The final germination percentages and the time in days required to reach 50% of germination (T50) were calculated. GA3 and C significantly enhanced completion of seed germination at all of the temperatures tested. A strong positive effect of alternating temperature was observed, which triggered completion of seed germination regardless of treatment. Under the fluctuating temperature, the chilled seeds had the most rapid germination. Low germination rates were observed for both control and DAR treatments. Seeds of C. vitalba display a certain degree of dormancy, which can be broken by moist chilling and GA3 treatments. Moreover, alternating temperature stimulates the completion of seed germination by satisfying certain physiological requirements for germination under constant temperatures.

Effect of Constant and Fluctuating Temperature on the Development, Reproduction, Survival, and Sex Ratio of Phenacoccus solenopsis (Hemiptera: Pseudococcidae)

2020 ◽  
Vol 49 (3) ◽  
pp. 553-560
Author(s):  
Muhammad Saad Waqas ◽  
Lulu Lin ◽  
Ali Ahmed Zaky Shoaib ◽  
Xinlai Cheng ◽  
Qianqian Zhang ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Constant Temperature ◽  
Oviposition Period ◽  
Adult Longevity ◽  
Developmental Duration ◽  
Phenacoccus Solenopsis ◽  
Fluctuating Temperature ◽  
Laboratory Conditions ◽  
Preoviposition Period ◽  
Fluctuating Temperatures

Abstract Effects of temperature on the development, survival, reproduction, longevity and sex ratio of the cotton mealybug, Phenacoccus solenopsis Tinsley, was assessed at five constant temperatures ranging from 20 to 35°C and five fluctuating temperatures ranging from 15 to 40°C under laboratory conditions. Results showed that nymphal development duration, preoviposition period, oviposition period, fecundity, and adult longevity were reduced significantly with increasing temperature until 30°C, but developmental duration of third female nymphal instar and female adult longevity was longer at 35°C than 30°C, and no males could emerge from pupae at the constant temperature 35°C. Fluctuating temperature, in general, significantly accelerated the nymphal developmental duration, prolonged preoviposition period, shortened oviposition period, reduced fecundity, lowered the survival rate of nymphs, and decreased adult longevity of males and females compared to their mean corresponding constant temperature. Overall, it is suggested that one should be prudent when applying the obtained results under constant and fluctuating temperatures under laboratory conditions.

scholarly journals Properties of Extruded Snacks Prepared from Corn and Carrot Powder with Ascorbic Acid Addition

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1367
Author(s):  
Valentina Obradović ◽  
Jurislav Babić ◽  
Verica Dragović-Uzelac ◽  
Antun Jozinović ◽  
Đurđica Ačkar ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Temperature Regime ◽  
External Source ◽  
Single Screw Extruder ◽  
Functional Value ◽  
Temperature Regimes ◽  
Starting Point ◽  
Extruded Snacks ◽  
New Type ◽  
Corn Snacks

The objective of this research was to investigate the potentiality of carrot powder (CP) utilization at levels 4, 6, or 8% as ingredient of corn snacks and evaluation of the extrusion influence on functionally important ingredients such as carotenoids (color), polyphenols, fiber, fat, and antioxidant activity. The influence of ascorbic acid (AA) as an external source at levels 0.5 and 1% on this particular extrusion was also investigated. A single-screw extruder at two temperature regimes (135/170/170 °C (E1) and 100/150/150 °C (E2)) carried out extrusion. The E1 temperature regime acted favorably on total polyphenol content and crude fiber, but fat preferred the E2 regime. Extrusion, especially the E1 temperature regime, increased the extractability of carotenoids. Ascorbic acid degraded during extrusion, but it still provided protection to carotenoids and color attributes of extrudates. Snacks with increased nutritional and functional value due to carrot powder addition were successfully produced, which is a starting point for production of a new type of extruded snacks.

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