scholarly journals The effect of respiratory gases and incubation temperature on early stage embryonic development in sea turtles

2020 ◽  
Author(s):  
David Terrington Booth ◽  
Alexander Archibald-Binge ◽  
Colin James Limpus
Keyword(s):  
Carbon Dioxide ◽  
Embryonic Development ◽  
Embryo Development ◽  
Incubation Temperature ◽  
Early Stage ◽  
Sea Turtle ◽  
Low Oxygen ◽  
Prolonged Incubation ◽  
Mature Embryos ◽  
Stage Embryo

AbstractSea turtle embryos at high density nesting beaches experience relative high rates of early stage embryo death. One hypothesis to explain this high dead rate is that there is an increased probability that newly constructed nests are located close to maturing clutches whose metabolising embryos cause low oxygen levels, high carbon dioxide levels, and high temperatures. Although these altered environmental conditions are well tolerated by mature embryos, early stage embryos may not be as tolerant leading to an increase in their mortality. To test this hypothesis, we incubated newly laid sea turtle eggs for a week over a range of temperatures in different combinations of oxygen and carbon dioxide concentrations and assessed embryo development and death rates. We found that gas mixtures of decreased oxygen and increased carbon dioxide, similar to those found in natural sea turtle nest containing mature embryos, slowed embryonic development but did not influence embryo mortality of early stage embryos. In contrast, high incubation temperature not only decreased embryo development rate, but prolonged incubation at 34°C was fatal.

scholarly journals The effect of respiratory gases and incubation temperature on early stage embryonic development in sea turtles

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0233580
Author(s):  
David Terrington Booth ◽  
Alexander Archibald-Binge ◽  
Colin James Limpus
Keyword(s):  
Carbon Dioxide ◽  
Incubation Temperature ◽  
Early Stage ◽  
Sea Turtle ◽  
High Density ◽  
Low Oxygen ◽  
Mature Embryos ◽  
Stage Embryo ◽  
Nesting Beaches ◽  
High Carbon Dioxide

Sea turtle embryos at high-density nesting beaches experience relative high rates of early stage embryo death. One hypothesis to explain this high mortality rate is that there is an increased probability that newly constructed nests are located close to maturing clutches whose metabolising embryos cause low oxygen levels, high carbon dioxide levels, and high temperatures. Although these altered environmental conditions are well tolerated by mature embryos, early stage embryos, i.e. embryos in eggs that have only been incubating for less than a week, may not be as tolerant leading to an increase in their mortality. To test this hypothesis, we incubated newly laid sea turtle eggs over a range of temperatures in different combinations of oxygen and carbon dioxide concentrations and assessed embryo development and death rates. We found that gas mixtures of decreased oxygen and increased carbon dioxide, similar to those found in natural sea turtle nests containing mature embryos, slowed embryonic development but did not influence the mortality rate of early stage embryos. We found incubation temperature had no effect on early embryo mortality but growth rate at 27°C and 34°C was slower than at 30°C and 33°C. Our findings indicate that low oxygen and high carbon dioxide partial pressures are not the cause of the high early stage embryo mortality observed at high-density sea turtle nesting beaches, but there is evidence suggesting high incubation temperatures, particularly above 34°C are harmful. Any management strategies that can increase the spacing between nests or other strategies such as shading or irrigation that reduce sand temperature are likely to increase hatching success at high-density nesting beaches.

scholarly journals A method for the collection of early-stage sea turtle embryos

2020 ◽  
Vol 42 ◽  
pp. 59-65
Author(s):  
A Gárriz ◽  
SA Williamson ◽  
RG Evans ◽  
RD Reina
Keyword(s):  
Embryonic Development ◽  
Early Stage ◽  
Initial Period ◽  
Sea Turtle ◽  
Turtle Species ◽  
Total Rna ◽  
Rna Integrity ◽  
Rna Integrity Number ◽  
Stage Of Development ◽  
Before And After

Early-stage turtle embryos, immediately after oviposition, are very small (<5 mm diameter), hindering research on the initial period of embryonic development. For example, assessing whether turtle eggs had been fertilized and contained a viable embryo at oviposition, especially under field conditions, is complicated by the microscopic size of embryos that may have died at an early stage of development. Further, little is known about the molecular pathways that promote and regulate early developmental processes in turtles, such as pre-ovipositional embryonic arrest. To enable further investigation of the processes critical to early embryonic development in turtle species, a reliable method is required for extraction of early-stage embryos from the egg. Therefore, our aim was to develop a novel and reproducible method for extracting early-stage sea turtle embryos. Herein, we describe the technique for extracting Chelonia mydas embryos before and after white spot formation. Once the embryos were collected, the total RNA of 10 embryos was extracted to validate the method. The total RNA concentration was above 5 ng µl-1 and the RNA integrity number varied between 7.0 and 10.0, which is considered acceptable for further RNA-sequencing analyses. This extraction technique could be employed when investigating fertilization rates of turtle nests and for further investigation of the molecular biology of embryonic development in turtles. Furthermore, the technique should be adaptable to other turtle species or any oviparous species with similar eggs.

scholarly journals EMBRYO DEVELOPMENT OF YELLOWFIN TUNA (Thunnus albacares) AT DIFFERENT INCUBATION TEMPERATURE

2007 ◽  
Vol 2 (2) ◽  
pp. 99
Author(s):  
Jhon Harianto Hutapea
Keyword(s):  
Embryonic Development ◽  
Embryo Development ◽  
Incubation Temperature ◽  
Sea Water ◽  
Digital Camera ◽  
Ultra Violet ◽  
Yellowfin Tuna ◽  
Thunnus Albacares ◽  
Image Analyzer ◽  
Micro Plates

<p>The experiment was conducted in order to figure out the effect of incubation temperature on embryonic development of yellowfin tuna, <em>Thunnus albacares</em> eggs. Five different incubation temperatures were applied as treatments, i.e.: 24°C, 26°C, 28°C, 30°C, and 32°C with 3 replicate each. Ten micro plates with lid (IWAKI, Japan) were used; each has 6 well and 10 mL volumes. Five micro plates were used for experiment and five for balance on shaker. Three well of each micro plate were filled with 8 mL ultra violet sterilized sea water and 50 fertilized eggs. Temperature was set using Multi Thermo Incubator which has 5 level racks. Temperatures were set from the lowest to the highest on bottom to upper rack order. To maintain eggs dispersed in the medium, shaker on each rack was operated at 150 RPM. The embryo was monitored every 30-60 minutes depends on embryonic stage development using Microscope which was connected to Digital Camera DXM 1200F. Image analyses by Image Analyzer Program. The results showed, incubation temperature was significantly affect (P&lt;0.05) embryonic development and hatching time of yellowfin tuna (<em>Thunnus albacares</em>) eggs. Optimum incubation temperature for embryo development and hatching was 28°C. Decreased on incubation temperature slows down embryo development at all stages, and vice versa, increased on incubation temperature accelerates embryo development.</p>

scholarly journals Transcriptomic Time-Series Analyses of Gene Expression Profile During Zygotic Embryo Development in Picea mongolica

2021 ◽  
Vol 12 ◽  
Author(s):  
Jia Yan ◽  
Ha buer ◽  
Ya ping Wang ◽  
Gegen zhula ◽  
Yu´e Bai
Keyword(s):  
Gene Expression ◽  
Embryo Development ◽  
Transcriptional Activation ◽  
Large Scale ◽  
Zygotic Embryo ◽  
Early Stage ◽  
Zygotic Embryos ◽  
Zygotic Embryogenesis ◽  
Mature Embryos ◽  
Picea Mongolica

Zygotic embryogenesis is a critical process during seed development in gymnosperms. However, knowledge on the genome-wide transcriptional activation that guides this process in conifers is limited, especially in Picea mongolica. This tree species is endemic to semiarid habitats of Inner Mongolia in China. To extend what is known about the molecular events underpinning its zygotic embryogenesis, comparative transcriptomic analyses of gene expression in zygotic embryos were performed by RNA sequencing in P. mongolica. Our results showed that most changes in transcript levels occurred in the early embryonic pattering determination and formation of mature embryos. Transcripts related to embryogenic competence, cell division pattern, hormones, and stress response genes were identified during embryogenesis. Auxin is essential for early embryo patterning and pre-cotyledon embryonic formation. However, ABA is a major regulator of embryo maturation. Moreover, we found that methylation-related gene expression is associated with activation of early-stage embryos, late embryogenesis abundant proteins, and storage/energy-related genes with late and mature embryos. Furthermore, network analysis revealed stage-specific and multistage gene expression clusters during embryogenesis. WOX, MYB, AP2, and HLH transcription factors seem more relevant to embryogenesis in different stages. Our results provide large-scale and comprehensive transcriptome data for embryo development in P. mongolica. These data will lay a foundation for the protection and utilization of P. mongolica resources.

DEVELOPMENT OF THE EMBRYO OF MEDICAGO SATIVA L. AFTER NORMAL FERTILIZATION AND AFTER POLLINATION BY OTHER SPECIES OF MEDICAGO

1963 ◽  
Vol 41 (1) ◽  
pp. 23-33 ◽  
Author(s):  
Sturla Fridriksson ◽  
J. L. Bolton
Keyword(s):  
Embryonic Development ◽  
Medicago Sativa ◽  
Embryo Development ◽  
Mature Seed ◽  
Pollen Parent ◽  
Full Size ◽  
Mature Embryos ◽  
Medicago Sativa L ◽  
Food Reserves ◽  
Normal Fertilization

The embryonic development of diploid and tetraploid Medicago sativa from the formation of the zygote to mature seed is described and illustrated. The embryo reaches the global stage at 7 to 8 days; the heart stage at 11 to 13 days; and the torpedo stage at 14 to 16 days after pollination. Full size is attained at about 25 days but food reserves apparently continue to be stored and maturity may not be reached until about the 35th day.Pollination of M. sativa stigmas with pollen from highly incompatible species failed to produce mature embryos. Crosses involving M. lupulina produced no sign of embryo development. However, when M. arborea, M. blancheana, M. marina, M. platycarpos, M. rigidula, M. ruthenica, or M. scutellata was used as a pollen parent the early stages of embryonic growth were initiated.

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