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Tanwar AK, Dhillon MK, Hasan F, Kumar S, Kirti JS. Lipid composition differs in diapause and nondiapause states of spotted stem borer, Chilo partellus. Comp Biochem Physiol B Biochem Mol Biol 2024; 274:110996. [PMID: 38810773 DOI: 10.1016/j.cbpb.2024.110996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 05/23/2024] [Accepted: 05/25/2024] [Indexed: 05/31/2024]
Abstract
Spotted stem borer, Chilo partellus, undergoes larval diapause (hibernation and aestivation), and depends on the food reserve accumulated during feeding stage for its survival. Lipids are the primary source of energy during diapause, and essential for different cellular, biochemical and physiological functions. However, there is no information on lipid and lipophilic compound contents during different stages of hibernation, aestivation and nondiapause in C. partellus. Thus, we compared the concentration and composition of lipids in pre-diapause, diapause and post-diapause stages of hibernation and aestivation with nondiapause stages of C. partellus. The studies revealed significant differences in total lipids and various lipophilic compounds during different stages of diapause as compared to nondiapause C. partellus. The total lipids were significantly lower during diapause stage of aestivation and hibernation as compared to nondiapause larvae. Further, the linoleic acid, Methyl 3-methoxytetradecanoate, and l-(+)-Ascorbic acid 2,6-dihexadecanoate were significantly lower, and oleic and palmitoleic acids greater during pre-diapause and diapause stages of hibernation and aestivation as compared to nondiapause larvae. The cholesterol content was significantly greater during pre-diapause stage of hibernation, and diapause and post-diapause stages of aestivation as compared to nondiapause stages. The unsaturation ratio was significantly higher in the pre-diapause and diapause stages and lower in post-diapause stage of aestivation than the hibernation and nondiapause states. This study provides insights on differential lipid profiles during different phases of diapause, which could be useful for further understanding biochemical and physiological cross-talk, and develop target-specific technologies for the management of C. partellus.
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Affiliation(s)
- Aditya K Tanwar
- Division of Entomology, ICAR-Indian Agricultural Research Institute, New Delhi, India; Department of Zoology and Environmental Sciences, Punjabi University, Patiala, Punjab, India
| | - Mukesh K Dhillon
- Division of Entomology, ICAR-Indian Agricultural Research Institute, New Delhi, India.
| | - Fazil Hasan
- Department of Agricultural Sciences, Noida International University, Uttar Pradesh, India
| | - Sandeep Kumar
- Biochemistry Laboratory, Germplasm Evaluation Division, ICAR-National Bureau of Plant Genetic Resources, New Delhi 110 012, India
| | - Jagbir S Kirti
- Department of Zoology and Environmental Sciences, Punjabi University, Patiala, Punjab, India
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Sau AK, Dhillon MK, Tanwar AK. Diapause-induced shift in the content of major carbohydrates in Chilo partellus (Swinhoe). JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2024; 341:193-202. [PMID: 38149458 DOI: 10.1002/jez.2774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2023] [Revised: 10/17/2023] [Accepted: 11/29/2023] [Indexed: 12/28/2023]
Abstract
Although several aspects like diapause determining factors, population structure, reproductive physiology, and genetics of diapause have been investigated, there is no clarity on carbohydrate energetics during larval diapause in Chilo partellus (Swinhoe). Present studies revealed significant variation between the nondiapausing and diapausing C. partellus for total carbohydrates, glycogen, sorbitol, and trehalose contents in different body parts, life stages, and for body parts × life stages interaction. Total carbohydrate content started declining, while sorbitol and trehalose increased in all the body parts as the C. partellus larvae progressed from prediapausing to diapausing state. However, glycogen content spiked in all the body parts at prediapausing stage, which then declined during diapause. Among the body parts, total carbohydrate content was significantly greater in the hemolymph as compared to other body parts of both larvae and pupae of C. partellus. Glycogen content was significantly greater in the larval fat bodies and pupal hemolymph as compared to their other body parts. In diapausing larvae, sorbitol and trehalose were greater in the integument than in other body parts. Furthermore, there was spike in trehalose and decrease in sorbitol in all the body parts of pupae from diapausing than those from nondiapausing larvae. These findings suggest that the diapause alterate and/or fluctuate major carbohydrates in different body parts of both larvae and pupae of C. partellus. This information will be helpful in better understanding the diapause energetics and overwintering metabolic cryoprotection in insects.
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Affiliation(s)
- Ashok K Sau
- Division of Entomology, ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - Mukesh K Dhillon
- Division of Entomology, ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - Aditya K Tanwar
- Division of Entomology, ICAR-Indian Agricultural Research Institute, New Delhi, India
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Wang B, Huang D, Cao C, Gong Y. Insect α-Amylases and Their Application in Pest Management. Molecules 2023; 28:7888. [PMID: 38067617 PMCID: PMC10708458 DOI: 10.3390/molecules28237888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 11/27/2023] [Accepted: 11/29/2023] [Indexed: 12/18/2023] Open
Abstract
Amylase is an indispensable hydrolase in insect growth and development. Its varied enzymatic parameters cause insects to have strong stress resistance. Amylase gene replication is a very common phenomenon in insects, and different copies of amylase genes enable changes in its location and function. In addition, the classification, structure, and interaction between insect amylase inhibitors and amylases have also invoked the attention of researchers. Some plant-derived amylase inhibitors have inhibitory activities against insect amylases and even mammalian amylases. In recent years, an increasing number of studies have clarified the effects of pesticides on the amylase activity of target and non-target pests, which provides a theoretical basis for exploring safe and efficient pesticides, while the exact lethal mechanisms and safety in field applications remain unclear. Here, we summarize the most recent advances in insect amylase studies, including its sequence and characteristics and the regulation of amylase inhibitors (α-AIs). Importantly, the application of amylases as the nanocide trigger, RNAi, or other kinds of pesticide targets will be discussed. A comprehensive foundation will be provided for applying insect amylases to the development of new-generation insect management tools and improving the specificity, stability, and safety of pesticides.
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Affiliation(s)
| | | | - Chunxia Cao
- National Biopesticide Engineering Research Centre, Hubei Biopesticide Engineering Research Centre, Hubei Academy of Agricultural Sciences, Wuhan 430064, China; (B.W.)
| | - Yan Gong
- National Biopesticide Engineering Research Centre, Hubei Biopesticide Engineering Research Centre, Hubei Academy of Agricultural Sciences, Wuhan 430064, China; (B.W.)
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Xie Z, Xu L, Zhao J, Li N, Qin D, Xiao C, Lu Y, Guo Z. Rapid cold hardening and cold acclimation promote cold tolerance of oriental fruit fly, Bactrocera dorsalis (Hendel) by physiological substances transformation and cryoprotectants accumulation. BULLETIN OF ENTOMOLOGICAL RESEARCH 2023; 113:574-586. [PMID: 37501573 DOI: 10.1017/s0007485323000251] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Insect response to cold stress is often associated with adaptive strategies and chemical variation. However, low-temperature domestication to promote the cold tolerance potential of Bactrocera dorsalis and transformation of main internal substances are not clear. Here, we use a series of low-temperature exposure experiments, supercooling point (SCP) measurement, physiological substances and cryoprotectants detection to reveal that pre-cooling with milder low temperatures (5 and 10°C) for several hours (rapid cold hardening) and days (cold acclimation) can dramatically improve the survival rate of adults and pupae under an extremely low temperature (-6.5°C). Besides, the effect of rapid cold hardening for adults could be maintained even 4 h later with 25°C exposures, and SCP was significantly declined after cold acclimation. Furthermore, content of water, fat, protein, glycogen, sorbitol, glycerol and trehalose in bodies were measured. Results showed that water content was reduced and increased content of proteins, glycogen, glycerol and trehalose after two cold domestications. Our findings suggest that rapid cold hardening and cold acclimation could enhance cold tolerance of B. dorsalis by increasing proteins, glycerol, trehalose and decreasing water content. Conclusively, identifying a physiological variation will be useful for predicting the occurrence and migration trend of B. dorsalis populations.
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Affiliation(s)
- Zifei Xie
- College of Plant Protection, Yunnan Agricultural University/State Key Laboratory of Yunnan Biological Resources Protection and Utilization, Kunming 650201, China
| | - Luchen Xu
- College of Plant Protection, Yunnan Agricultural University/State Key Laboratory of Yunnan Biological Resources Protection and Utilization, Kunming 650201, China
| | - Jie Zhao
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
| | - Na Li
- College of Plant Protection, Yunnan Agricultural University/State Key Laboratory of Yunnan Biological Resources Protection and Utilization, Kunming 650201, China
| | - Deqiang Qin
- College of Plant Protection, Yunnan Agricultural University/State Key Laboratory of Yunnan Biological Resources Protection and Utilization, Kunming 650201, China
| | - Chun Xiao
- College of Plant Protection, Yunnan Agricultural University/State Key Laboratory of Yunnan Biological Resources Protection and Utilization, Kunming 650201, China
| | - Yongyue Lu
- College of Plant Protection, South China Agricultural University, Guangzhou 510640, China
| | - Zijun Guo
- College of Plant Protection, Yunnan Agricultural University/State Key Laboratory of Yunnan Biological Resources Protection and Utilization, Kunming 650201, China
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Zhao L, Wang X, Liu Z, Torson AS. Energy Consumption and Cold Hardiness of Diapausing Fall Webworm Pupae. INSECTS 2022; 13:853. [PMID: 36135554 PMCID: PMC9505466 DOI: 10.3390/insects13090853] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 09/11/2022] [Accepted: 09/12/2022] [Indexed: 06/16/2023]
Abstract
Diapause and cold hardiness are essential components of winter survival for most insects in temperate zones. The fall webworm, Hyphantria cunea, overwinters in a pupal diapause. In this study, we investigated the energy consumption and cold hardiness of diapausing pupae. We found that lipid content decreased from October to November and stabilized from November to March. Glycogen content decreased by 61.3% and 52.2% for females and males, respectively, from October to November, and decreased slowly from November to March. We also observed a significant increase in trehalose concentrations as ambient temperatures decreased from October to November and a decrease in trehalose as temperatures increased again in March. We did not observe substantial changes in pupal supercooling points among the dates sampled. In addition, prolonged pupal development time reduced their survival rate and had no significant effect on post-diapause adult body mass and fecundity but reduced egg diameter in females. These results suggest that the energy consumption of H. cunea pupae during early diapause depends on lipid and glycogen, while it shifts to depend on glycogen or other energy stores in the mid- and late diapause stages. Our results also suggest that the prolonged development time of diapausing pupae had a negative effect on post-diapause fitness.
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Affiliation(s)
- Lvquan Zhao
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing 210037, China; (X.W.); (Z.L.)
| | - Xinmei Wang
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing 210037, China; (X.W.); (Z.L.)
| | - Zheng Liu
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing 210037, China; (X.W.); (Z.L.)
| | - Alex S. Torson
- USDA-ARS Edward T. Schafer Agricultural Research Center, Biosciences Research Laboratory, Fargo, ND 58102, USA;
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Tanwar AK, Kirti JS, Kumar S, Dhillon MK. The amino acid and lipophilic profiles of Chilo partellus (Swinhoe) larvae fluctuate with diapause. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2021; 335:595-601. [PMID: 34185965 DOI: 10.1002/jez.2502] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 06/05/2021] [Accepted: 06/16/2021] [Indexed: 11/10/2022]
Abstract
The Chilo partellus (Crambidae: Lepidoptera) larvae undergoes both hibernation and estivation in India. Although, much has been done on reproductive physiological aspects, little is known about biochemical changes happening during hibernation and estivation in C. partellus. Thus, we mapped changes in amino acid and lipophilic profiles of C. partellus larvae while undergoing hibernation and estivation using high-performance liquid chromatography and gas chromatography mass spectroscopy. The studies revealed higher amounts of amino acids namely, serine, glycine, histidine, arginine, proline, tyrosine, and methionine in estivation, while lower in hibernation as compared with nondiapause larvae of C. partellus. Furthermore, the amounts of aspartic acid, glutamic acid, and alanine in hibernation, and threonine, valine, isoleucine, phenylalanine, and leucine in estivation were on par with nondiapause larvae. The lipophilic compounds namely, linoleic acid, stearic acid, eicosanoic acid, and n-pentadecanol were lower in hibernation than estivation and nondiapause larvae of C. partellus. Palmitoleic acid and methyl 3-methoxytetradecanoate contents were higher in hibernation than estivation and nondiapause, while myristic acid and lathosterol contents were higher in estivation than hibernation and nondiapause larvae of C. partellus. Cholesterol content was higher, while squalene and gamma-ergostenol were lower in hibernation and estivation as compared with nondiapause larvae of C. partellus. These findings suggest that certain amino acids may be constituents of heat-shock proteins and help C. partellus during estivation. However, the lipophilic compounds could be helpful in maintaining development during hibernation and estivation in C. partellus.
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Affiliation(s)
- Aditya K Tanwar
- Division of Entomology, ICAR-Indian Agricultural Research Institute, New Delhi, India.,Department of Zoology and Environmental Sciences, Punjabi University, Patiala, Punjab, India
| | - Jagbir S Kirti
- Department of Zoology and Environmental Sciences, Punjabi University, Patiala, Punjab, India
| | - Sandeep Kumar
- Biochemistry Laboratory, ICAR-National Bureau of Plant Genetic Resources, New Delhi, India
| | - Mukesh K Dhillon
- Division of Entomology, ICAR-Indian Agricultural Research Institute, New Delhi, India
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Zhao L, Wang W. Effects of Autumn Warming on Energy Consumption of Diapausing Fall Webworm (Lepidoptera: Arctiidae) Pupae. JOURNAL OF INSECT SCIENCE (ONLINE) 2021; 21:6209913. [PMID: 33822125 PMCID: PMC8023358 DOI: 10.1093/jisesa/ieab021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Indexed: 06/12/2023]
Abstract
Since its invasion into China in 1979, the fall webworm, Hyphantria cunea Drury, has spread from Dandong city (about 40°N) in Liaoning Province to Nanjing city (about 32°N) in Jiangsu Province, and to other areas. Owing to geographic and latitudinal gradients in temperature, H. cunea will encounter temperature changes during the spreading process. In this study, we verified the hypothesis that autumn warming accelerates the energy consumption of H. cunea diapause pupae. We found that, after autumn warming, the body size and mass of diapause pupae decreased significantly and raised constant temperature accelerated carbohydrate and protein consumption in female pupae, while fluctuating temperature changes had a more pronounced effect on carbohydrate and protein consumption in male pupae. Contrary to expectations, the lipid content of diapause pupae did not decrease after autumn warming, and even increased significantly. We conclude that warming in autumn accelerates energy consumption by diapause pupae, and the autumn energy consumption of diapause pupae is dominated by carbohydrates, supplemented by protein when carbohydrates are overconsumed, while lipid use is dominated by anabolic metabolism during autumn.
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Affiliation(s)
- Lvquan Zhao
- Co-innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing 210037, China
| | - Wei Wang
- Co-innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing 210037, China
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Simultaneous Occurrence of Diapause and Cold Hardiness in Overwintering Eggs of the Apple Oystershell Scale, Lepidosaphes Malicola Borchsenius (Hem.: Diaspididae). Zool Stud 2020; 59:e25. [PMID: 33262848 DOI: 10.6620/zs.2020.59-25] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 05/20/2020] [Indexed: 11/18/2022]
Abstract
As the key pest of apple fruits, the oystershell scale, Lepidosaphes malicola Borchsenius (Hem.: Diaspididae), overwinters as diapausing eggs under the protective, waxy cover of females. In this research, the effects of diapause development, cold acclimation, and rapid cold hardening were studied on the cold hardiness of the eggs. The changes in some physiological components were also investigated. The results indicated cold exposure to be a prerequisite for the survival of the diapausing eggs of L. malicola. No eggs hatched without exposure to cold. In addition, a direct relationship was observed among cold hardiness, cold acclimation, and diapause of the eggs based on the results. The highest level of hatching (the highest cold hardiness) of the eggs (80%) occurred in the cold-acclimated eggs at the end of diapause (March). Rapid cold hardening also influenced the cold hardiness of the eggs with diapause development. At the end of diapause, the lowest (61%) and the highest (77%) rates of egg survival were observed when the eggs were exposed to 5 and -10°C for 24 h, respectively. Cold hardiness of the diapausing eggs of L. malicola was also accompanied by some physiological changes, i.e., a decrease in glycogen content and an increase in simple sugar, lipid, and protein contents. The lowest glycogen content (about 50 μg/g) and the highest amounts of total simple sugars (454 μg/g) of lipids (542 μg/g) and proteins (84 μg/g) were observed in the cold-acclimated eggs at the end of diapause.
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Hasanvand H, Izadi H, Mohammadzadeh M. Overwintering Physiology and Cold Tolerance of the Sunn Pest, Eurygaster integriceps, an Emphasis on the Role of Cryoprotectants. Front Physiol 2020; 11:321. [PMID: 32425803 PMCID: PMC7204558 DOI: 10.3389/fphys.2020.00321] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 03/20/2020] [Indexed: 12/17/2022] Open
Abstract
As a serious pest of wheat, the Sunn pest, Eurygaster integriceps Puton (Hem.: Scutelleridae), is prevalent in Iran. This pest belongs to univoltine species and tends to estivate and overwinter in high altitudes of nearby mountains as diapausing adults. The economic importance of the crop was attacked by this pest, i.e., wheat led the authors to study the physiological adaptations of these diapausing adults, that is, changes in the supercooling point (SCP), in the accumulation of cryoprotectants, and in the activities of the related enzymes in relation to diapause development. The mean SCP of the diapausing adults was found to be −8°C. The lowest SCP, i.e., approximately −11°C, was observed in the middle of diapause, October, when the highest cold hardiness was also interestingly recorded. This finding proposed that SCP depression could be a feasible cold-tolerance strategy for diapausing adults. The sugar content was high in the initiation and at the termination of diapause and was low during diapause maintenance. These sugar reserves were most likely utilized to be converted to glycogen and lipid during diapause maintenance as a survival strategy. The changes in the glycogen and lipid contents were inversely proportional to the changes in the total sugar content. The authors also found that the changes in the glycogen content were directly proportional to those in the low-molecular-weight carbohydrates (e.g., glycerol and trehalose) and in the diapause development. This finding underlined the role of the low-molecular-weight carbohydrates, such as the cryoprotectants, in enhancing the cold tolerance of the given insect. In this study, the diapause-associated changes in the activities of α-amylases and proteases were also investigated. The results showed that the enzyme activities were related to diapause development and cold-tolerance enhancement. The highest enzyme activity was observed in September. Since the overwintering adults of the Sunn pest could not tolerate temperatures below their SCPs, they were grouped in the freeze-intolerant species.
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Affiliation(s)
- Hamzeh Hasanvand
- Department of Plant Protection, Faculty of Agriculture, Vali-e-Asr University of Rafsanjan, Rafsanjan, Iran
| | - Hamzeh Izadi
- Department of Plant Protection, Faculty of Agriculture, Vali-e-Asr University of Rafsanjan, Rafsanjan, Iran
| | - Mozhgan Mohammadzadeh
- Department of Plant Protection, Faculty of Agriculture, Vali-e-Asr University of Rafsanjan, Rafsanjan, Iran
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Batz ZA, Armbruster PA. Diapause-associated changes in the lipid and metabolite profiles of the Asian tiger mosquito, Aedes albopictus. J Exp Biol 2018; 221:jeb189480. [PMID: 30385483 PMCID: PMC6307873 DOI: 10.1242/jeb.189480] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 10/24/2018] [Indexed: 12/31/2022]
Abstract
Diapause is an alternative life-history strategy that allows organisms to enter developmental arrest in anticipation of unfavorable conditions. Diapause is widespread among insects and plays a key role in enhancing overwinter survival as well as defining the seasonal and geographic distributions of populations. Next-generation sequencing has greatly advanced our understanding of the transcriptional basis for this crucial adaptation but less is known about the regulation of embryonic diapause physiology at the metabolite level. Here, we characterized the lipid and metabolite profiles of embryonic diapause in the Asian tiger mosquito, Aedes albopictus We used an untargeted approach to capture the relative abundance of 250 lipids and 241 metabolites. We observed adjustments associated with increased energy storage, including an accumulation of lipids, the formation of larger lipid droplets and increased lipogenesis, as well as metabolite shifts suggesting reduced energy utilization. We also found changes in neuroregulatory- and insulin-associated metabolites with potential roles in diapause regulation. Finally, we detected a group of unidentified, diapause-specific metabolites which have physical properties similar to those of steroids/steroid derivatives and may be associated with the ecdysteroidal regulation of embryonic diapause in A.albopictus Together, these results deepen our understanding of the metabolic regulation of embryonic diapause and identify key targets for future investigations.
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Affiliation(s)
- Zachary A Batz
- Department of Biology, Georgetown University, 37th and O Streets NW, Washington, DC 20057, USA
| | - Peter A Armbruster
- Department of Biology, Georgetown University, 37th and O Streets NW, Washington, DC 20057, USA
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Mohammadzadeh M, Izadi H. Cold Acclimation of Trogoderma granarium Everts Is Tightly Linked to Regulation of Enzyme Activity, Energy Content, and Ion Concentration. Front Physiol 2018; 9:1427. [PMID: 30425644 PMCID: PMC6218610 DOI: 10.3389/fphys.2018.01427] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Accepted: 09/20/2018] [Indexed: 12/22/2022] Open
Abstract
In this study, cold hardiness and some physiological characteristics of the Khapra beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae) larvae, were investigated under different thermal regimes, i.e., control, cold-acclimated (CA), fluctuating-acclimated (FA), and rapid cold-hardened (RCH). In all the regimes, the larval survival rate decreased with a decrease in temperature. CA larvae showed the highest cold hardiness following 24 h exposure at -15 and -20°C. Control larvae had the highest glycogen content (34.4 ± 2.3 μg/dry weight). In contrast, CA larvae had the lowest glycogen content (23.0 ± 1.6 μg/dry weight). Change in trehalose content was reversely proportional to changes in glycogen content. The highest myo-inositol and glucose contents were detected in CA larvae (10.7 ± 0.4 μg/dry weight) and control (0.49 ± 0.03 μg/dry weight), respectively. In control and treated larvae, [Na+] decreased, though [K+] increased, with increasing exposure time. The shape of the thermal reaction curve of AMP-depended protein kinase and protein phosphatase 2C followed the same norm, which was different from protein phosphatase 1 and protein phosphatase 2A. Protein phosphatase 2A and 2C showed a complete difference in thermal reaction norms. Indeed, thermal fluctuation caused the highest changes in the activity of the enzymes, whereas the RCH showed the lowest changes in the activity of the enzymes. Our results showed a significant enhancement of larval cold tolerance under CA regime, which is related to the high levels of low molecular weight carbohydrates under this regime. Our results showed that among the different thermal regimes tested, the CA larvae had the lowest supercooling point (about -22°C) and the highest cold hardiness following 24 h exposure at -15 and -20°C.
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Affiliation(s)
- Mozhgan Mohammadzadeh
- Department of Plant Protection, Faculty of Agriculture, Vali-e-Asr University of Rafsanjan, Rafsanjan, Iran
| | - Hamzeh Izadi
- Department of Plant Protection, Faculty of Agriculture, Vali-e-Asr University of Rafsanjan, Rafsanjan, Iran
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