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Zhu BT. Biochemical mechanism underlying the pathogenesis of diabetic retinopathy and other diabetic complications in humans: the methanol-formaldehyde-formic acid hypothesis. Acta Biochim Biophys Sin (Shanghai) 2022; 54:415-451. [PMID: 35607958 PMCID: PMC9828688 DOI: 10.3724/abbs.2022012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 11/18/2021] [Indexed: 11/25/2022] Open
Abstract
Hyperglycemia in diabetic patients is associated with abnormally-elevated cellular glucose levels. It is hypothesized that increased cellular glucose will lead to increased formation of endogenous methanol and/or formaldehyde, both of which are then metabolically converted to formic acid. These one-carbon metabolites are known to be present naturally in humans, and their levels are increased under diabetic conditions. Mechanistically, while formaldehyde is a cross-linking agent capable of causing extensive cytotoxicity, formic acid is an inhibitor of mitochondrial cytochrome oxidase, capable of inducing histotoxic hypoxia, ATP deficiency and cytotoxicity. Chronic increase in the production and accumulation of these toxic one-carbon metabolites in diabetic patients can drive the pathogenesis of ocular as well as other diabetic complications. This hypothesis is supported by a large body of experimental and clinical observations scattered in the literature. For instance, methanol is known to have organ- and species-selective toxicities, including the characteristic ocular lesions commonly seen in humans and non-human primates, but not in rodents. Similarly, some of the diabetic complications (such as ocular lesions) also have a characteristic species-selective pattern, closely resembling methanol intoxication. Moreover, while alcohol consumption or combined use of folic acid plus vitamin B is beneficial for mitigating acute methanol toxicity in humans, their use also improves the outcomes of diabetic complications. In addition, there is also a large body of evidence from biochemical and cellular studies. Together, there is considerable experimental support for the proposed hypothesis that increased metabolic formation of toxic one-carbon metabolites in diabetic patients contributes importantly to the development of various clinical complications.
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Affiliation(s)
- Bao Ting Zhu
- Shenzhen Key Laboratory of Steroid Drug Discovery and DevelopmentSchool of MedicineThe Chinese University of Hong KongShenzhen518172China
- Department of PharmacologyToxicology and TherapeuticsSchool of MedicineUniversity of Kansas Medical CenterKansas CityKS66160USA
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James ER, Wen Y, Overby J, Pluchino K, McTighe S, Matheny S, Eappen A, Hoffman SL, Billingsley PF. Cryopreservation of Anopheles stephensi embryos. Sci Rep 2022; 12:43. [PMID: 34997079 PMCID: PMC8741979 DOI: 10.1038/s41598-021-04113-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Accepted: 12/10/2021] [Indexed: 11/09/2022] Open
Abstract
The ability to cryopreserve mosquitoes would revolutionize work on these vectors of major human infectious diseases by conserving stocks, new isolates, lab-bred strains, and transgenic lines that currently require continuous life cycle maintenance. Efforts over several decades to develop a method for cryopreservation have, until now, been fruitless: we describe here a method for the cryopreservation of Anopheles stephensi embryos yielding hatch rates of ~ 25%, stable for > 5 years. Hatched larvae developed into fertile, fecund adults and blood-fed females, produced fully viable second generation eggs, that could be infected with Plasmodium falciparum at high intensities. The key components of the cryopreservation method are: embryos at 15-30 min post oviposition, two incubation steps in 100% deuterated methanol at - 7 °C and - 14.5 °C, and rapid cooling. Eggs are recovered by rapid warming with concomitant dilution of cryoprotectant. Eggs of genetically modified A. stephensi and of A. gambiae were also successfully cryopreserved. This enabling methodology will allow long-term conservation of mosquitoes as well as acceleration of genetic studies and facilitation of mass storage of anopheline mosquitoes for release programs.
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Affiliation(s)
| | | | | | | | - Shane McTighe
- Sanaria Inc, Rockville, MD, USA.,Department of Dermatology, Walter Reed National Military Medical Center, Rockville, MD, USA
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Gallichotte EN, Dobos KM, Ebel GD, Hagedorn M, Rasgon JL, Richardson JH, Stedman TT, Barfield JP. Towards a method for cryopreservation of mosquito vectors of human pathogens. Cryobiology 2021; 99:1-10. [PMID: 33556359 DOI: 10.1016/j.cryobiol.2021.02.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 01/23/2021] [Accepted: 02/01/2021] [Indexed: 12/13/2022]
Abstract
Mosquito-borne diseases are responsible for millions of human deaths every year, posing a massive burden on global public health. Mosquitoes transmit a variety of bacteria, parasites and viruses. Mosquito control efforts such as insecticide spraying can reduce mosquito populations, but they must be sustained in order to have long term impacts, can result in the evolution of insecticide resistance, are costly, and can have adverse human and environmental effects. Technological advances have allowed genetic manipulation of mosquitoes, including generation of those that are still susceptible to insecticides, which has greatly increased the number of mosquito strains and lines available to the scientific research community. This generates an associated challenge, because rearing and maintaining unique mosquito lines requires time, money and facilities, and long-term maintenance can lead to adaptation to specific laboratory conditions, resulting in mosquito lines that are distinct from their wild-type counterparts. Additionally, continuous rearing of transgenic lines can lead to loss of genetic markers, genes and/or phenotypes. Cryopreservation of valuable mosquito lines could help circumvent these limitations and allow researchers to reduce the cost of rearing multiple lines simultaneously, maintain low passage number transgenic mosquitoes, and bank lines not currently being used. Additionally, mosquito cryopreservation could allow researchers to access the same mosquito lines, limiting the impact of unique laboratory or field conditions. Successful cryopreservation of mosquitoes would expand the field of mosquito research and could ultimately lead to advances that would reduce the burden of mosquito-borne diseases, possibly through rear-and-release strategies to overcome mosquito insecticide resistance. Cryopreservation techniques have been developed for some insect groups, including but not limited to fruit flies, silkworms and other moth species, and honeybees. Recent advances within the cryopreservation field, along with success with other insects suggest that cryopreservation of mosquitoes may be a feasible method for preserving valuable scientific and public health resources. In this review, we will provide an overview of basic mosquito biology, the current state of and advances within insect cryopreservation, and a proposed approach toward cryopreservation of Anopheles stephensi mosquitoes.
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Affiliation(s)
- Emily N Gallichotte
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
| | - Karen M Dobos
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
| | - Gregory D Ebel
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
| | - Mary Hagedorn
- Smithsonian Conservation Biology Institute, Smithsonian Institution, Front Royal, VA, USA; Hawaii Institute of Marine Biology, University of Hawaii, Kaneohe, HI, USA
| | - Jason L Rasgon
- Department of Entomology, The Pennsylvania State University, University Park, PA, USA; Center for Infectious Disease Dynamics, The Pennsylvania State University, University Park, PA, USA; Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, USA
| | | | | | - Jennifer P Barfield
- Department of Biomedical Sciences, Animal Reproduction and Biotechnology Laboratory, Colorado State University, Fort Collins, CO, USA.
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Nesbitt JE, Swei A, Hunt C, Dotson EM, Toner M, Sandlin RD. Cryoprotectant toxicity and hypothermic sensitivity among Anopheles larvae. Cryobiology 2020; 99:106-113. [PMID: 33382993 DOI: 10.1016/j.cryobiol.2020.12.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 11/30/2020] [Accepted: 12/23/2020] [Indexed: 01/06/2023]
Abstract
Laboratory rearing of mosquitoes is commonly practiced by researchers studying mosquito-borne infectious diseases and vector control methods. In the absence of cryopreservation methods to stabilize unique or genetically modified strains, mosquito lines must be continuously maintained, a laborious process that risks selection effects, contamination, and genetic drift. Towards the development of a cryopreservation protocol, several commonly used cryoprotectants were systematically characterized here both individually and as cocktails. Among first instar, feeding-stage An. gambiae and An. stephensi larvae, cryoprotectant toxicity followed the order of dimethyl sulfoxide > ethylene glycol > methanol. The resulting LD50 values were used as the basis for the development of cryoprotectant cocktail solutions, where formulation optimization was streamlined using Taguchi methods of experimental design. Sensitivity to hypothermia was further evaluated to determine the feasibility of cryoprotectant loading at reduced temperatures and slow cooling approaches to cryopreservation. The information described here contributes to the knowledge base necessary to inform the development of a cryopreservation protocol for Anopheles larvae.
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Affiliation(s)
- Jenny E Nesbitt
- BioMEMS Resource Center, Center for Engineering in Medicine, & Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
| | - Anisa Swei
- BioMEMS Resource Center, Center for Engineering in Medicine, & Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
| | - Catherine Hunt
- Centers for Disease Control and Prevention, Atlanta, GA, USA.
| | - Ellen M Dotson
- Centers for Disease Control and Prevention, Atlanta, GA, USA.
| | - Mehmet Toner
- BioMEMS Resource Center, Center for Engineering in Medicine, & Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
| | - Rebecca D Sandlin
- BioMEMS Resource Center, Center for Engineering in Medicine, & Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
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Campbell JB, Dosch A, Hunt CM, Dotson EM, Benedict MQ, Rajamohan A, Rinehart JP. Physiological responses to cryoprotectant treatment in an early larval stage of the malaria mosquito, Anopheles gambiae. Cryobiology 2020; 99:114-121. [PMID: 33279509 DOI: 10.1016/j.cryobiol.2020.12.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 10/27/2020] [Accepted: 12/01/2020] [Indexed: 10/22/2022]
Abstract
The development of cryopreservation protocols for Anopheles gambiae could significantly improve research and control efforts. Cryopreservation of any An. gambiae life stage has yet to be successful. The unique properties of embryos have proven to be resistant to any practical cryoprotectant loading. Therefore, we have chosen to investigate early non-feeding first instar larvae as a potential life stage for cryopreservation. In order to determine an appropriate cryoprotective compound, larvae were treated with progressively better glass-forming cryoprotective mixtures. Toxicity evaluation in combination with calorimetry-based water content and supercooling point depression assessments were used to determine the cryoprotectants that could be used for cryostorage of viable larvae. Approximately 35-75% of the larvae were viable after reasonably high osmotic and biochemical challenge. This study provides ample evidence for an active osmoregulatory response in the Anopheles larvae to counter the permeation of cryoprotectants from the surrounding medium. The data show a strong correlation between the larval mortality and water content, indicating an osmoregulatory crisis in the larva due to certain cryoprotectants such as the higher concentrations of ethane diol (ED). The observations also indicate that the ability of the larvae to regulate permeation and water balance ceases at or within 20 min of cryoprotectant exposure, but this is strongly influenced by the treatment temperature. Among the compound cryoprotectants tested, 25% ED + 10% dimethyl sulfoxide (DMSO) and 40% ED + 0.5 M trehalose seem to present a compromise between viability, larval water content, supercooling point depression, and glass forming abilities.
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Affiliation(s)
- Jacob B Campbell
- Insect Genetics and Biochemistry Unit, Biosciences Research Lab, USDA-ARS, Fargo, ND, USA.
| | - Andrew Dosch
- Insect Genetics and Biochemistry Unit, Biosciences Research Lab, USDA-ARS, Fargo, ND, USA
| | - Catherine M Hunt
- Center for Disease Control and Prevention, Division of Parasitic Diseases and Malaria, Entomology Branch, Atlanta, GA, USA
| | - Ellen M Dotson
- Center for Disease Control and Prevention, Division of Parasitic Diseases and Malaria, Entomology Branch, Atlanta, GA, USA
| | - Mark Q Benedict
- Center for Disease Control and Prevention, Division of Parasitic Diseases and Malaria, Entomology Branch, Atlanta, GA, USA
| | - Arun Rajamohan
- Insect Genetics and Biochemistry Unit, Biosciences Research Lab, USDA-ARS, Fargo, ND, USA
| | - Joseph P Rinehart
- Insect Genetics and Biochemistry Unit, Biosciences Research Lab, USDA-ARS, Fargo, ND, USA
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Bazbouz MB, Taylor M, Baker D, Ries ME, Goswami P. Dry-jet wet electrospinning of native cellulose microfibers with macroporous structures from ionic liquids. J Appl Polym Sci 2018. [DOI: 10.1002/app.47153] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
| | - Mark Taylor
- School of Design; University of Leeds; Leeds LS2 9JT United Kingdom
| | - Daniel Baker
- School of Physics and Astronomy; University of Leeds; Leeds LS2 9JT United Kingdom
| | - Michael E. Ries
- School of Physics and Astronomy; University of Leeds; Leeds LS2 9JT United Kingdom
| | - Parikshit Goswami
- Department of Fashion and Textiles; University of Huddersfield; Huddersfield HD1 3DH United Kingdom
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Ameen I, Tripathi AK, Siddiqui A, Kapil G, Pandey SS, Tripathi UN. Synthesis, characterizations and photo-physical properties of novel lanthanum(III) complexes. JOURNAL OF TAIBAH UNIVERSITY FOR SCIENCE 2018. [DOI: 10.1080/16583655.2018.1516028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Iffat Ameen
- Department of Chemistry, Deen Dayal Upadhyay Gorakhpur University, Gorakhpur, India
| | | | - Afshan Siddiqui
- Department of Chemistry, Deen Dayal Upadhyay Gorakhpur University, Gorakhpur, India
| | - Gaurav Kapil
- Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, Wakamatsu, Kitakyushu, Japan
| | - Shyam S. Pandey
- Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, Wakamatsu, Kitakyushu, Japan
| | - Umesh Nath Tripathi
- Department of Chemistry, Deen Dayal Upadhyay Gorakhpur University, Gorakhpur, India
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Dorokhov YL, Shindyapina AV, Sheshukova EV, Komarova TV. Metabolic methanol: molecular pathways and physiological roles. Physiol Rev 2015; 95:603-44. [PMID: 25834233 DOI: 10.1152/physrev.00034.2014] [Citation(s) in RCA: 122] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Methanol has been historically considered an exogenous product that leads only to pathological changes in the human body when consumed. However, in normal, healthy individuals, methanol and its short-lived oxidized product, formaldehyde, are naturally occurring compounds whose functions and origins have received limited attention. There are several sources of human physiological methanol. Fruits, vegetables, and alcoholic beverages are likely the main sources of exogenous methanol in the healthy human body. Metabolic methanol may occur as a result of fermentation by gut bacteria and metabolic processes involving S-adenosyl methionine. Regardless of its source, low levels of methanol in the body are maintained by physiological and metabolic clearance mechanisms. Although human blood contains small amounts of methanol and formaldehyde, the content of these molecules increases sharply after receiving even methanol-free ethanol, indicating an endogenous source of the metabolic methanol present at low levels in the blood regulated by a cluster of genes. Recent studies of the pathogenesis of neurological disorders indicate metabolic formaldehyde as a putative causative agent. The detection of increased formaldehyde content in the blood of both neurological patients and the elderly indicates the important role of genetic and biochemical mechanisms of maintaining low levels of methanol and formaldehyde.
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Affiliation(s)
- Yuri L Dorokhov
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, Russia; and N. I. Vavilov Institute of General Genetics, Russian Academy of Science, Moscow, Russia
| | - Anastasia V Shindyapina
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, Russia; and N. I. Vavilov Institute of General Genetics, Russian Academy of Science, Moscow, Russia
| | - Ekaterina V Sheshukova
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, Russia; and N. I. Vavilov Institute of General Genetics, Russian Academy of Science, Moscow, Russia
| | - Tatiana V Komarova
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, Russia; and N. I. Vavilov Institute of General Genetics, Russian Academy of Science, Moscow, Russia
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Dixit S, Upadhyay SK, Singh H, Sidhu OP, Verma PC, K C. Enhanced methanol production in plants provides broad spectrum insect resistance. PLoS One 2013; 8:e79664. [PMID: 24223989 PMCID: PMC3818224 DOI: 10.1371/journal.pone.0079664] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Accepted: 09/23/2013] [Indexed: 01/22/2023] Open
Abstract
Plants naturally emit methanol as volatile organic compound. Methanol is toxic to insect pests; but the quantity produced by most of the plants is not enough to protect them against invading insect pests. In the present study, we demonstrated that the over-expression of pectin methylesterase, derived from Arabidopsis thaliana and Aspergillus niger, in transgenic tobacco plants enhances methanol production and resistance to polyphagous insect pests. Methanol content in the leaves of transgenic plants was measured using proton nuclear spectroscopy (1H NMR) and spectra showed up to 16 fold higher methanol as compared to control wild type (WT) plants. A maximum of 100 and 85% mortality in chewing insects Helicoverpa armigera and Spodoptera litura larvae was observed, respectively when fed on transgenic plants leaves. The surviving larvae showed less feeding, severe growth retardation and could not develop into pupae. In-planta bioassay on transgenic lines showed up to 99 and 75% reduction in the population multiplication of plant sap sucking pests Myzus persicae (aphid) and Bemisia tabaci (whitefly), respectively. Most of the phenotypic characters of transgenic plants were similar to WT plants. Confocal microscopy showed no deformities in cellular integrity, structure and density of stomata and trichomes of transgenic plants compared to WT. Pollen germination and tube formation was also not affected in transgenic plants. Cell wall enzyme transcript levels were comparable with WT. This study demonstrated for the first time that methanol emission can be utilized for imparting broad range insect resistance in plants.
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Affiliation(s)
- Sameer Dixit
- CSIR-National Botanical Research Institute, Council of Scientific and Industrial Research, Lucknow, Uttar Pradesh, India
- Academy of Scientific and Innovative Research (AcSIR), Anusandhan Bhawan, 2-Rafi Marg, New Delhi, India
| | - Santosh Kumar Upadhyay
- CSIR-National Botanical Research Institute, Council of Scientific and Industrial Research, Lucknow, Uttar Pradesh, India
- Department of Biotechnology, National Agri-Food Biotechnology Institute, Ministry of Science and Technology, Mohali, Punjab, India
| | - Harpal Singh
- CSIR-National Botanical Research Institute, Council of Scientific and Industrial Research, Lucknow, Uttar Pradesh, India
| | - Om Prakash Sidhu
- CSIR-National Botanical Research Institute, Council of Scientific and Industrial Research, Lucknow, Uttar Pradesh, India
| | - Praveen Chandra Verma
- CSIR-National Botanical Research Institute, Council of Scientific and Industrial Research, Lucknow, Uttar Pradesh, India
- Academy of Scientific and Innovative Research (AcSIR), Anusandhan Bhawan, 2-Rafi Marg, New Delhi, India
| | - Chandrashekar K
- CSIR-National Botanical Research Institute, Council of Scientific and Industrial Research, Lucknow, Uttar Pradesh, India
- Indian Agricultural Research Institute, Shivaji Nagar, Pune, Maharashtra, India
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Pandey A, Misra P, Chandrashekar K, Trivedi PK. Development of AtMYB12-expressing transgenic tobacco callus culture for production of rutin with biopesticidal potential. PLANT CELL REPORTS 2012; 31:1867-76. [PMID: 22733206 DOI: 10.1007/s00299-012-1300-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Revised: 05/24/2012] [Accepted: 06/08/2012] [Indexed: 06/01/2023]
Abstract
UNLABELLED Flavonoids synthesized by the phenylpropanoid pathway participate in a number of physiological and biochemical processes in plants. Flavonols, among flavonoids, are considered as health-protective components in functional foods and they protect plants against certain insect pests. There have been efforts to develop strategies for the enhanced production of flavonols in plants, but limited success was achieved due to complex regulation and poor substrate availability. In the present study, we have developed and optimized method for callus cultures for transgenic tobacco line expressing a flavonol-specific transcription factor, AtMYB12, with an objective to use callus as an alternative source of rutin. Transgenic callus displayed enhanced expression of genes related to biosynthetic pathway leading to increased accumulation of flavonols, especially rutin. At each time point of callus growth, the rutin content of transgenic callus was several folds higher than that of wild-type tobacco callus. Supplementation of semi-synthetic diet with extract from transgenic callus as well as purified rutin led to mortality and growth reduction in the Spodoptera litura and Helicoverpa armigera larvae. This study suggests the biotechnological potential of AtMYB12-expressing callus cultures for the production of rutin, which can be used for biopesticide formulations against insect pests. KEY MESSAGE Tobacco callus cultures expressing AtMYB12 accumulate enhanced content of rutin and can be used as a potential alternative source of rutin as well as biopesticides against insect pests.
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Affiliation(s)
- Ashutosh Pandey
- CSIR-National Botanical Research Institute, Rana Pratap Marg, Lucknow, 226 001, India
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Liu XH, Mazur P. Effects of sugars on the kinetics of drying and on the survival of partially dehydrated larvae of Anopheles mosquitoes. JOURNAL OF INSECT PHYSIOLOGY 2003; 49:685-695. [PMID: 12837321 DOI: 10.1016/s0022-1910(03)00070-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The ability to cryopreserve a stage of Anopheles mosquitoes would facilitate the development of strains incapable of transmitting malaria. Cryopreservation requires that the freezable water in cell systems be removed or rendered incapable of undergoing ice formation. The present study was concerned with the rate at which water is removed from lst instar larvae of Anopheles gambiae by air-drying, with the extent of dehydration that the larvae will tolerate, and with the effect of trehalose and sucrose on both drying kinetics and survival. Eighty-one percent of the larvae are water. Air-drying removes 90% of that water in approximately 20 min. Survivals after partial dehydration are highest if the larvae are rehydrated in 1/2x isotonic saline (0.13 osm); they are poorest if rehydrated in water or 0.13 osm sucrose. In the former, about 34% survive the removal of half the water, but next to none survive the loss of >70% initial water. Prior exposure to 0.2 M trehalose for as little as 1 min slows the drying rate and increases the tolerance of the larvae to dehydration. With 30-min exposure, 88% survive the loss of 50% of their water and 63% survive the loss of 75%. Protection is abolished with 0.4 M trehalose. The results are similar with sucrose. It is substantially reduced if sugar-exposed larvae are briefly washed with water prior to drying. The protection appears not to be related to the decreased drying rate. Rather it appears related, by an unknown mechanism, to the presence of sugar on the outer surface of the larvae.
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Affiliation(s)
- Xiang-Hong Liu
- University of Tennessee, Department of Biochemistry and Cellular and Molecular Biology, 10515 Research Drive, Knoxville, TN 37932-2575, USA
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