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Peng Z, Xiang A, He H, Luo Y, Wu S, Luo Y, Yang J, Nie K, Zhong X. Brimonidine as a possible treatment for myopia. BMC Ophthalmol 2024; 24:161. [PMID: 38605375 PMCID: PMC11007938 DOI: 10.1186/s12886-024-03433-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Accepted: 04/04/2024] [Indexed: 04/13/2024] Open
Abstract
BACKGROUND Myopia is becoming a huge burden on the world's public health systems. The purpose of this study was to explore the effect of brimonidine in the treatment of form-deprivation myopia (FDM) and the relationship between intraocular pressure (IOP) and myopia development. METHODS Monocular form deprivation myopia (FDM) was induced in three-week-old pigmented male guinea pigs. They were treated with 3 different methods of brimonidine administration (eye drops, and subconjunctival or intravitreal injections). Four different concentrations of brimonidine were tested for each method (2µg/µL, 4µg/µL, 20µg/µL, and 40µg/µL). All treatments continued for a period of 21 days. Tonometry, retinoscopy, and A-scan ultrasonography were used to monitor intraocular pressure, refractive error and axial length (AL), respectively. RESULTS Treatment with subconjunctival brimonidine at 40µg/µL, and intravitreal brimonidine at 2µg/µL and 4µg/µL, inhibited the development of FDM. The myopic refraction, excessive axial length, and elevation of IOP were significantly decreased. Brimonidine in eye drops was ineffective. CONCLUSION Brimonidine at appropriate doses significantly reduced the development of FD myopia in guinea pigs. The IOP may change with FD myopia.
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Affiliation(s)
- Zixuan Peng
- Hainan Provincial Key Laboratory of Ophthalmology, Hainan Eye Hospital, Zhongshan Ophthalmic Center, Sun Yat-sen University, No. 19 Xiuhua Road, Xiuying District, 570300, Haikou, Hainan, China
- Hainan Medical University, Haikou, Hainan, China
| | - Aiqun Xiang
- Hainan Provincial Key Laboratory of Ophthalmology, Hainan Eye Hospital, Zhongshan Ophthalmic Center, Sun Yat-sen University, No. 19 Xiuhua Road, Xiuying District, 570300, Haikou, Hainan, China
| | - Hong He
- Hainan Provincial Key Laboratory of Ophthalmology, Hainan Eye Hospital, Zhongshan Ophthalmic Center, Sun Yat-sen University, No. 19 Xiuhua Road, Xiuying District, 570300, Haikou, Hainan, China.
| | - Yaqi Luo
- Hainan Provincial Key Laboratory of Ophthalmology, Hainan Eye Hospital, Zhongshan Ophthalmic Center, Sun Yat-sen University, No. 19 Xiuhua Road, Xiuying District, 570300, Haikou, Hainan, China
- Hainan Medical University, Haikou, Hainan, China
| | - Shunliang Wu
- Hainan Provincial Key Laboratory of Ophthalmology, Hainan Eye Hospital, Zhongshan Ophthalmic Center, Sun Yat-sen University, No. 19 Xiuhua Road, Xiuying District, 570300, Haikou, Hainan, China
- Hainan Medical University, Haikou, Hainan, China
| | - Yanting Luo
- Hainan Provincial Key Laboratory of Ophthalmology, Hainan Eye Hospital, Zhongshan Ophthalmic Center, Sun Yat-sen University, No. 19 Xiuhua Road, Xiuying District, 570300, Haikou, Hainan, China
- Hainan Medical University, Haikou, Hainan, China
| | - Junming Yang
- Hainan Provincial Key Laboratory of Ophthalmology, Hainan Eye Hospital, Zhongshan Ophthalmic Center, Sun Yat-sen University, No. 19 Xiuhua Road, Xiuying District, 570300, Haikou, Hainan, China
- Hainan Medical University, Haikou, Hainan, China
| | - Ke Nie
- Hainan Provincial Key Laboratory of Ophthalmology, Hainan Eye Hospital, Zhongshan Ophthalmic Center, Sun Yat-sen University, No. 19 Xiuhua Road, Xiuying District, 570300, Haikou, Hainan, China
- Hainan Medical University, Haikou, Hainan, China
| | - Xingwu Zhong
- Hainan Provincial Key Laboratory of Ophthalmology, Hainan Eye Hospital, Zhongshan Ophthalmic Center, Sun Yat-sen University, No. 19 Xiuhua Road, Xiuying District, 570300, Haikou, Hainan, China.
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.
- Hainan Medical University, Haikou, Hainan, China.
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Xu J, Lei X, Li A, Li J, Li S, Chen L. Scalable production of recombinant three-finger proteins: from inclusion bodies to high quality molecular probes. Microb Cell Fact 2024; 23:48. [PMID: 38347541 PMCID: PMC10860255 DOI: 10.1186/s12934-024-02316-1] [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: 04/25/2022] [Accepted: 08/10/2022] [Indexed: 02/15/2024] Open
Abstract
BACKGROUND The three-finger proteins are a collection of disulfide bond rich proteins of great biomedical interests. Scalable recombinant expression and purification of bioactive three-finger proteins is quite difficult. RESULTS We introduce a working pipeline for expression, purification and validation of disulfide-bond rich three-finger proteins using E. coli as the expression host. With this pipeline, we have successfully obtained highly purified and bioactive recombinant α-Βungarotoxin, k-Bungarotoxin, Hannalgesin, Mambalgin-1, α-Cobratoxin, MTα, Slurp1, Pate B etc. Milligrams to hundreds of milligrams of recombinant three finger proteins were obtained within weeks in the lab. The recombinant proteins showed specificity in binding assay and six of them were crystallized and structurally validated using X-ray diffraction protein crystallography. CONCLUSIONS Our pipeline allows refolding and purifying recombinant three finger proteins under optimized conditions and can be scaled up for massive production of three finger proteins. As many three finger proteins have attractive therapeutic or research interests and due to the extremely high quality of the recombinant three finger proteins we obtained, our method provides a competitive alternative to either their native counterparts or chemically synthetic ones and should facilitate related research and applications.
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Affiliation(s)
- Jiang Xu
- Molecular and Computational Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA, 90089, USA.
| | - Xiao Lei
- Molecular and Computational Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA, 90089, USA
| | - Ao Li
- Molecular and Computational Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA, 90089, USA
| | - Jun Li
- Institute of Clinical Medicine, The First Affiliated Hospital of University of South China, Hengyang, Hunan, 421001, People's Republic of China
| | - Shuxing Li
- Molecular and Computational Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA, 90089, USA
| | - Lin Chen
- Molecular and Computational Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA, 90089, USA.
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Captive Black Mamba (Dendroaspis Polylepis) Bite Leading to Respiratory Failure. J Emerg Med 2023; 64:311-314. [PMID: 36925444 DOI: 10.1016/j.jemermed.2023.01.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 01/06/2023] [Indexed: 03/15/2023]
Abstract
BACKGROUND Of the 8000-10,000 snake envenomations evaluated in U.S. emergency departments (ED) annually, approximately 1% are due to non-native snakes. We describe a 26-year-old man who was bitten by his captive black mamba (Dendroaspis polylepis) as he was packing it up for transport to another snake collector. CASE REPORT The patient presented to the ED 1 h after being bitten on the forearm, complaining of left arm pain, oral paresthesias, and dyspnea. His vital signs: heart rate 96 beats/min, blood pressure 167/101 mm Hg, temperature 36.7°C (97.9°F), respiratory rate 20 breaths/min, and room air oxygen saturation 100%. Two mildly tender puncture wounds without swelling or ecchymosis were found on the posterior aspect of the forearm. Over the ensuing 30 min his dyspnea worsened, and he developed objective weakness. He was intubated and placed on mechanical ventilation. He was treated with atropine 2 mg for bronchorrhea. Five vials of South African Vaccine Producers (Johannesburg, South Africa) polyvalent antivenom were administered 2.5 h post-bite and the patient was admitted to the intensive care unit. He was extubated 18 h post-envenomation and discharged the following day. He has remained asymptomatic since leaving the hospital. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: The primary manifestations of D. polylepis envenomings are neurological. Initial signs may include paresthesias, dysarthria, dysphagia, and ptosis. Progressive descending paralysis leading to respiratory failure develops within 60 min. Muscarinic features are frequently observed. Cardiotoxicity and hematologic laboratory abnormalities may be present. Although pain is common, significant local tissue injury does not occur. In addition to supportive care, several non-native antivenoms are indicated for D. polylepis envenomations. Black mamba envenomings differ from the native snakebites with which U.S. physicians are familiar. Rapid, progressive neurological toxicity and muscarinic features are most common. Treatment consists of supportive care and appropriate antivenom administration.
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Yang Y, Wu J, Wu D, Wei Q, Zhong T, Yang J, Yang X, Zeng M, Zhong X. Intravitreal brimonidine inhibits form-deprivation myopia in guinea pigs. EYE AND VISION 2021; 8:27. [PMID: 34256866 PMCID: PMC8278638 DOI: 10.1186/s40662-021-00248-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Accepted: 05/24/2021] [Indexed: 11/15/2022]
Abstract
Background The use of ocular hypotensive drugs has been reported to attenuate myopia progression. This study explores whether brimonidine can slow myopia progression in the guinea pig form-deprivation (FD) model. Methods Three-week-old pigmented male guinea pigs (Cavia porcellus) underwent monocular FD and were treated with 3 different methods of brimonidine administration (eye drops, subconjunctival or intravitreal injections). Four different concentrations of brimonidine were tested for intravitreal injection (2 μg/μL, 4 μg/μL, 20 μg/μL, 40 μg/μL). All treatments continued for a period of 21 days. Tonometry, retinoscopy, and A-scan ultrasonography were used to monitor intraocular pressure (IOP), refractive error and axial length (AL), respectively. On day 21, guinea pigs were sacrificed for RNA sequencing (RNA-seq) to screen for associated transcriptomic changes. Results The myopia model was successfully established in FD animals (control eye vs. FD eye, respectively: refraction at day 20, 0.97 ± 0.18 D vs. − 0.13 ± 0.38 D, F = 6.921, P = 0.02; AL difference between day 0 and day 21, 0.29 ± 0.04 mm vs. 0.45 ± 0.03 mm, F = 11.655, P = 0.004). Among the 3 different brimonidine administration methods, intravitreal injection was the most effective in slowing myopia progression, and 4 μg/μL was the most effective among the four different concentrations of brimonidine intravitreal injection tested. The AL and the refraction of the brimonidine intravitreal injection group was significantly shorter or more hyperopic than those of other 2 groups. Four μg/μL produced the smallest difference in AL and spherical equivalent difference values. FD treatment significantly increased the IOP. IOP was significantly lower at 1 day after intravitreal injections which was the lowest in FD eye of intravitreal injection of brimonidine. At day 21, gene expression analyses using RNA-seq showed upregulation of Col1a1 and Mmp2 expression levels by intravitreal brimonidine. Conclusions Among the 3 different administration methods, intravitreal injection of brimonidine was the most effective in slowing myopia progression in the FD guinea pig model. Intravitreal brimonidine at 4 μg/μL significantly reduced the development of FD myopia in guinea pigs. Expression levels of the Col1a1 and Mmp2 genes were significantly increased in the retinal tissues of the FD-Inj-Br group. Supplementary Information The online version contains supplementary material available at 10.1186/s40662-021-00248-0.
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Trim CM, Byrne LJ, Trim SA. Utilisation of compounds from venoms in drug discovery. PROGRESS IN MEDICINAL CHEMISTRY 2021; 60:1-66. [PMID: 34147202 DOI: 10.1016/bs.pmch.2021.01.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Difficult drug targets are becoming the normal course of business in drug discovery, sometimes due to large interacting surfaces or only small differences in selectivity regions. For these, a different approach is merited: compounds lying somewhere between the small molecule and the large antibody in terms of many properties including stability, biodistribution and pharmacokinetics. Venoms have evolved over millions of years to be complex mixtures of stable molecules derived from other somatic molecules, the stability comes from the pressure to be ready for delivery at a moment's notice. Snakes, spiders, scorpions, jellyfish, wasps, fish and even mammals have evolved independent venom systems with complex mixtures in their chemical arsenal. These venom-derived molecules have been proven to be useful tools, such as for the development of antihypotensive angiotensin converting enzyme (ACE) inhibitors and have also made successful drugs such as Byetta® (Exenatide), Integrilin® (Eptifibatide) and Echistatin. Only a small percentage of the available chemical space from venoms has been investigated so far and this is growing. In a new era of biological therapeutics, venom peptides present opportunities for larger target engagement surface with greater stability than antibodies or human peptides. There are challenges for oral absorption and target engagement, but there are venom structures that overcome these and thus provide substrate for engineering novel molecules that combine all desired properties. Venom researchers are characterising new venoms, species, and functions all the time, these provide great substrate for solving the challenges presented by today's difficult targets.
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Affiliation(s)
- Carol M Trim
- Faculty of Science, Engineering and Social Sciences, Natural and Applied Sciences, School of Psychology and Life Sciences, Canterbury Christ Church University, Canterbury, Kent, United Kingdom
| | - Lee J Byrne
- Faculty of Science, Engineering and Social Sciences, Natural and Applied Sciences, School of Psychology and Life Sciences, Canterbury Christ Church University, Canterbury, Kent, United Kingdom
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Muratspahić E, Freissmuth M, Gruber CW. Nature-Derived Peptides: A Growing Niche for GPCR Ligand Discovery. Trends Pharmacol Sci 2019; 40:309-326. [PMID: 30955896 DOI: 10.1016/j.tips.2019.03.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 02/26/2019] [Accepted: 03/06/2019] [Indexed: 12/11/2022]
Abstract
G protein-coupled receptors (GPCRs) represent important drug targets, as they regulate pivotal physiological processes and they have proved to be readily druggable. Natural products have been and continue to be amongst the most valuable sources for drug discovery and development. Here, we surveyed small molecules and (poly-)peptides derived from plants, animals, fungi, and bacteria, which modulate GPCR signaling. Among naturally occurring compounds, peptides from plants, cone-snails, snakes, spiders, scorpions, fungi, and bacteria are of particular interest as lead compounds for the development of GPCR ligands, since they cover a chemical space, which differs from that of synthetic small molecules. Peptides, however, face challenges, some of which can be overcome by studying plant-derived compounds. We argue here that the opportunities outweigh the challenges.
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Affiliation(s)
- Edin Muratspahić
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Austria
| | - Michael Freissmuth
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Austria; Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center for Physiology and Pharmacology, Medical University of Vienna, Austria
| | - Christian W Gruber
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Austria.
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Carr BJ, Mihara K, Ramachandran R, Saifeddine M, Nathanson NM, Stell WK, Hollenberg MD. Myopia-Inhibiting Concentrations of Muscarinic Receptor Antagonists Block Activation of Alpha2A-Adrenoceptors In Vitro. Invest Ophthalmol Vis Sci 2019; 59:2778-2791. [PMID: 29860464 DOI: 10.1167/iovs.17-22562] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Myopia is a refractive disorder that degrades vision. It can be treated with atropine, a muscarinic acetylcholine receptor (mAChR) antagonist, but the mechanism is unknown. Atropine may block α-adrenoceptors at concentrations ≥0.1 mM, and another potent myopia-inhibiting ligand, mamba toxin-3 (MT3), binds equally well to human mAChR M4 and α1A- and α2A-adrenoceptors. We hypothesized that mAChR antagonists could inhibit myopia via α2A-adrenoceptors, rather than mAChR M4. Methods Human mAChR M4 (M4), chicken mAChR M4 (cM4), or human α2A-adrenergic receptor (hADRA2A) clones were cotransfected with CRE/promoter-luciferase (CRE-Luc; agonist-induced luminescence) and Renilla luciferase (RLuc; normalizing control) into human cells. Inhibition of normalized agonist-induced luminescence by antagonists (ATR: atropine; MT3; HIM: himbacine; PRZ: pirenzepine; TRP: tropicamide; OXY: oxyphenonium; QNB: 3-quinuclidinyl benzilate; DIC: dicyclomine; MEP: mepenzolate) was measured using the Dual-Glo Luciferase Assay System. Results Relative inhibitory potencies of mAChR antagonists at mAChR M4/cM4, from most to least potent, were QNB > OXY ≥ ATR > MEP > HIM > DIC > PRZ > TRP. MT3 was 56× less potent at cM4 than at M4. Relative potencies of mAChR antagonists at hADRA2A, from most to least potent, were MT3 > HIM > ATR > OXY > PRZ > TRP > QNB > MEP; DIC did not antagonize. Conclusions Muscarinic antagonists block hADRA2A signaling at concentrations comparable to those used to inhibit chick myopia (≥0.1 mM) in vivo. Relative potencies at hADRA2A, but not M4/cM4, correlate with reported abilities to inhibit chick form-deprivation myopia. mAChR antagonists might inhibit myopia via α2-adrenoceptors, instead of through the mAChR M4/cM4 receptor subtype.
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Affiliation(s)
- Brittany J Carr
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Inflammation Research Network-Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Neuroscience, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Koichiro Mihara
- Inflammation Research Network-Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Rithwik Ramachandran
- Inflammation Research Network-Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Physiology and Pharmacology, Western University, London, Ontario, Canada
| | - Mahmoud Saifeddine
- Inflammation Research Network-Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Neil M Nathanson
- Department of Pharmacology, University of Washington, Seattle, Washington, United States
| | - William K Stell
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Cell Biology and Anatomy, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Morley D Hollenberg
- Inflammation Research Network-Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Medicine, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
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Carr BJ, Nguyen CT, Stell WK. Alpha 2 -adrenoceptor agonists inhibit form-deprivation myopia in the chick. Clin Exp Optom 2019; 102:418-425. [PMID: 30699466 PMCID: PMC6617789 DOI: 10.1111/cxo.12871] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 11/22/2018] [Accepted: 12/09/2018] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND The putative myopia-controlling receptor is thought to be muscarinic acetylcholine receptor subtype M4 , because mamba toxin-3 can inhibit form-deprivation myopia in chicks at a far lower concentration than atropine. However, mamba toxin-3 is equally potent at the human α1A -, α1D -, and α2A -adrenoceptors. To test the hypothesis that α-adrenoceptors might be involved in regulation of eye growth, the treatment effects of α2 -adrenoceptor agonists brimonidine, clonidine, and guanfacine, and antagonist yohimbine, on form-deprivation myopia in the chick were measured. METHODS Right eyes of White Leghorn chicks were goggled with diffusers to induce form-deprivation myopia; left eyes were left open as controls. Goggled eyes were injected intravitreally with 20 μL of vehicle, or 2, 20, or 200 nmol of brimonidine, clonidine, guanfacine, or yohimbine, 24, 72, and 120 hours after goggle application. Alternatively, myopia was inhibited physiologically by goggle removal for two hours, and the α2 -adrenoceptor antagonist, yohimbine, was injected to test whether it could block this type of myopia inhibition. One day after the last injection, refractive error and axial length were measured. RESULTS Brimonidine (20 and 200 nmol) and clonidine (200 nmol) effectively inhibited experimentally induced increases in negative refractive error and axial elongation. All doses of guanfacine significantly inhibited induced negative refractive error, but only 20 and 200 nmol significantly inhibited axial elongation. Yohimbine had no effect on form-deprivation myopia, but 200 nmol reduced the myopia-inhibiting effect of goggle removal. CONCLUSION High concentrations of α2 -adrenoceptor agonists, similar to those required by atropine, inhibited chick form-deprivation myopia; antagonism by yohimbine had no effect. High-concentration yohimbine partially interfered with emmetropisation in form-deprived chicks experiencing normal vision for two hours per day. These data support the hypothesis that treatment with high concentrations of adrenergic drugs can affect experimentally induced myopia and normal visual processes.
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Affiliation(s)
- Brittany J Carr
- Department of Neuroscience, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Cynthia T Nguyen
- O'Brien Centre for the Bachelor of Health Sciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - William K Stell
- Department of Cell Biology and Anatomy, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
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Zhang Z, Zhou Y, Xie Z, Chen T, Gu Y, Lu S, Wu Z. The effect of topical atropine on the choroidal thickness of healthy children. Sci Rep 2016; 6:34936. [PMID: 27713535 PMCID: PMC5054672 DOI: 10.1038/srep34936] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 09/20/2016] [Indexed: 12/15/2022] Open
Abstract
The purpose of the current study was to investigate the effect of topical atropine on choroidal thickness using spectral-domain optical coherence tomography. A total of 30 healthy eyes from 30 children were analyzed in this study. A single drop of 1% atropine gel was administered twice daily for a week. Choroidal thickness (CT) was measured using SD-OCT, and changes in CT before and after administration of the eye drops were analyzed at the subfovea and at 1.0-mm intervals (up to 3.0 mm) from the fovea at superior, inferior, nasal, and temporal locations. Pre- and post-cycloplegic axial length (AL) was also measured using the IOLMaster. We observed that administration of 1% atropine gel led to a significant increase in the choroidal thickness under the fovea and at all intervals from the fovea. The greatest change in CT was observed in the inferior meridian, while the nasal meridian exhibited the least change. AL did not significantly differ before and after cycloplegia, and there was no significant correlation between the changes in AL and subfoveal CT. It was concluded that administration of 1% atropine gel can significantly increase CT in the eyes of young Chinese children, albeit with different magnitude at different locations.
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Affiliation(s)
- Zhengwei Zhang
- Department of Ophthalmology, Nanjing Medical University Affiliated Wuxi Second Hospital, Wuxi, Jiangsu Province, P. R.China
| | - Yuanting Zhou
- Department of Ophthalmology, Nanjing Medical University Affiliated Wuxi Second Hospital, Wuxi, Jiangsu Province, P. R.China
| | - Zhifang Xie
- Department of Ophthalmology, Nanjing Medical University Affiliated Wuxi Second Hospital, Wuxi, Jiangsu Province, P. R.China
| | - Tiantian Chen
- Department of Ophthalmology, Nanjing Medical University Affiliated Wuxi Second Hospital, Wuxi, Jiangsu Province, P. R.China
| | - Yan Gu
- Department of Ophthalmology, Nanjing Medical University Affiliated Wuxi Second Hospital, Wuxi, Jiangsu Province, P. R.China
| | - Shui Lu
- Department of Ophthalmology, Nanjing Medical University Affiliated Wuxi Second Hospital, Wuxi, Jiangsu Province, P. R.China
| | - Zhifeng Wu
- Department of Ophthalmology, Nanjing Medical University Affiliated Wuxi Second Hospital, Wuxi, Jiangsu Province, P. R.China
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Petras D, Heiss P, Harrison RA, Süssmuth RD, Calvete JJ. Top-down venomics of the East African green mamba, Dendroaspis angusticeps, and the black mamba, Dendroaspis polylepis, highlight the complexity of their toxin arsenals. J Proteomics 2016; 146:148-64. [PMID: 27318176 DOI: 10.1016/j.jprot.2016.06.018] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2016] [Revised: 06/04/2016] [Accepted: 06/13/2016] [Indexed: 01/24/2023]
Abstract
We report the characterization, by combination of high-resolution on-line molecular mass and disulfide bond profiling and top-down MS/MS analysis, of the venom proteomes of two congeneric African snake species of medical importance, Dendroaspis angusticeps (green mamba) and D. polylepis (black mamba). Each of these mamba venoms comprised more than two-hundred polypeptides belonging to just a few toxin families. Both venom proteomes are overwhelmingly composed of post-synaptically-acting short- and long-chain neurotoxins that potently inhibit muscle- and neuronal-type nicotinic acetylcholine receptors; muscarinic cardiotoxins; and dendrotoxins, that block some of the Kv1, n-class of K+ channels. However, the identity of the major proteins and their relative abundances exhibit marked interspecific variation. In addition, the greater resolution of the top-down venomic analytical approach revealed previously undetected protein species, isoforms and proteoforms, including the identification and precise location of modified lysine residues in a number of proteins in both venoms, but particularly in green mamba toxins. This comparative top-down venomic analysis unveiled the untapped complexity of Dendroaspis venoms and lays the foundations for rationalizing the notably different potency of green and black mamba lethal arsenals at locus resolution. SIGNIFICANCE PARAGRAPH We report the characterization, by combination of high-resolution on-line molecular mass and disulfide bond profiling and top-down MS/MS analysis, of the venom proteomes of two congeneric African snake species of medical importance, Dendroaspis angusticeps (green mamba) and D. polylepis (black mamba). Each of these mamba venoms comprised more than two-hundred polypeptides belonging to just a few toxin families. Both venom proteomes are overwhelmingly composed of post-synaptically-acting short- and long-chain neurotoxins that potently inhibit muscle- and neuronal-type nicotinic acetylcholine receptors; muscarinic cardiotoxins; and dendrotoxins, that block some of the Kv1, n-class of K+ channels. However, the identity of the major proteins and their relative abundances exhibit marked interspecific variation. In addition, the greater resolution of the top-down venomic analytical approach revealed previously undetected protein species, isoforms and proteoforms, including the identification and precise location of modified lysine residues in a number of proteins in both venoms, but particularly in green mamba toxins. This comparative top-down venomic analysis unveiled the untapped complexity of Dendroaspis venoms and lays the foundations for rationalizing the notably different potency of green and black mamba lethal arsenals at locus resolution.
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Affiliation(s)
- Daniel Petras
- Technische Universität Berlin, Institut für Chemie, Berlin, Germany; University of California-San Diego, Skaggs School of Pharmacy & Pharmaceutical Sciences, La Jolla, CA, USA
| | - Paul Heiss
- Technische Universität Berlin, Institut für Chemie, Berlin, Germany
| | - Robert A Harrison
- Alistair Reid Venom Research Unit, Liverpool, School of Tropical Medicine, Liverpool, United Kingdom
| | | | - Juan J Calvete
- Instituto de Biomedicina de Valencia, CSIC, Valencia, Spain.
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11
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Polypharmacology profiles and phylogenetic analysis of three-finger toxins from mamba venom: Case of aminergic toxins. Biochimie 2014; 103:109-17. [DOI: 10.1016/j.biochi.2014.04.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 04/22/2014] [Indexed: 12/21/2022]
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12
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McBrien NA, Stell WK, Carr B. How does atropine exert its anti-myopia effects? Ophthalmic Physiol Opt 2013; 33:373-8. [PMID: 23662969 DOI: 10.1111/opo.12052] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In the following point-counterpoint article, internationally-acclaimed myopia researchers were challenged to defend the two opposing sides of the topic defined by the title; their contributions, which appear in the order, Point followed by Counterpoint, were peer-reviewed by both the editorial team and an external reviewer. Independently of the invited authors, the named member of the editorial team provided an Introduction and Summary, both of which were reviewed by the other members of the editorial team. By their nature, views expressed in each section of the Point-Counterpoint article are those of the author concerned and may not reflect the views of all of the authors.
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Affiliation(s)
- Neville A McBrien
- Department of Optometry & Vision Sciences, University of Melbourne, Melbourne, Vic., Australia.
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13
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Blanchet G, Upert G, Mourier G, Gilquin B, Gilles N, Servent D. New α-adrenergic property for synthetic MTβ and CM-3 three-finger fold toxins from black mamba. Toxicon 2013; 75:160-7. [PMID: 23648423 DOI: 10.1016/j.toxicon.2013.04.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 04/15/2013] [Accepted: 04/19/2013] [Indexed: 12/28/2022]
Abstract
Despite their isolation more than fifteen years ago from the venom of the African mamba Dendroaspis polylepis, very few data are known on the functional activity of MTβ and CM-3 toxins. MTβ was initially classified as a muscarinic toxin interacting non-selectively and with low affinity with the five muscarinic receptor subtypes while no biological function was determined for CM-3. Recent results highlight the multifunctional activity of three-finger fold toxins for muscarinic and adrenergic receptors and reveal some discrepancies in the pharmacological profiles of their venom-purified and synthetic forms. Here, we report the pharmacological characterization of chemically-synthesized MTβ and CM-3 toxins on nine subtypes of muscarinic and adrenergic receptors and demonstrate their high potency for α-adrenoceptors and in particular a sub-nanomolar affinity for the α1A-subtype. Strikingly, no or very weak affinity were found for muscarinic receptors, highlighting that pharmacological characterizations of venom-purified peptides may be risky due to possible contaminations. The biological profile of these two homologous toxins looks like that one previously reported for the Dendroaspis angusticeps ρ-Da1a toxin. Nevertheless, MTβ and CM-3 interact more potently than ρ-Da1a with α1B- and α1D-AR subtypes. A computational analysis of the stability of the MTβ structure suggests that mutation S38I, could be involved in this gain in function.
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Affiliation(s)
- Guillaume Blanchet
- CEA, iBiTec-S, Service d'Ingénierie Moléculaire des Protéines (SIMOPRO), F-91191 Gif sur Yvette, France; UFR Sciences de la Vie, Université Pierre et Marie Curie (UPMC), 4 place Jussieu, Paris, France
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14
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Jäntti MH, Putula J, Turunen PM, Näsman J, Reijonen S, Lindqvist C, Kukkonen JP. Autocrine endocannabinoid signaling through CB1 receptors potentiates OX1 orexin receptor signaling. Mol Pharmacol 2012; 83:621-32. [PMID: 23233488 DOI: 10.1124/mol.112.080523] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
It has been proposed that OX(1) orexin receptors and CB(1) cannabinoid receptors can form heteromeric complexes, which affect the trafficking of OX(1) receptors and potentiate OX(1) receptor signaling to extracellular signal-regulated kinase (ERK). We have recently shown that OX(1) receptor activity releases high levels of the endocannabinoid 2-arachidonoyl glycerol (2-AG), suggesting an alternative route for OX(1)-CB(1) receptor interaction in signaling, for instance, in retrograde synaptic transmission. In the current study, we set out to investigate this possibility utilizing recombinant Chinese hamster ovary K1 cells. 2-AG released from OX(1) receptor-expressing cells acted as a potent paracrine messenger stimulating ERK activity in neighboring CB(1) receptor-expressing cells. When OX(1) and CB(1) receptors were expressed in the same cells, OX(1) stimulation-induced ERK phosphorylation and activity were strongly potentiated. The potentiation but not the OX(1) response as such was fully abolished by specific inhibition of CB(1) receptors or the enzyme responsible for 2-AG generation, diacylglycerol lipase (DAGL). Although the results do not exclude the previously proposed OX(1)-CB(1) heteromerization, they nevertheless unequivocally identify DAGL-dependent 2-AG generation as the pivotal determinant of the OX(1)-CB(1) synergism and thus suggest a functional rather than a molecular interaction of OX(1) and CB(1) receptors.
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Affiliation(s)
- Maria H Jäntti
- Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland
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15
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Fruchart-Gaillard C, Mourier G, Blanchet G, Vera L, Gilles N, Ménez R, Marcon E, Stura EA, Servent D. Engineering of three-finger fold toxins creates ligands with original pharmacological profiles for muscarinic and adrenergic receptors. PLoS One 2012; 7:e39166. [PMID: 22720062 PMCID: PMC3375269 DOI: 10.1371/journal.pone.0039166] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Accepted: 05/16/2012] [Indexed: 01/26/2023] Open
Abstract
Protein engineering approaches are often a combination of rational design and directed evolution using display technologies. Here, we test “loop grafting,” a rational design method, on three-finger fold proteins. These small reticulated proteins have exceptional affinity and specificity for their diverse molecular targets, display protease-resistance, and are highly stable and poorly immunogenic. The wealth of structural knowledge makes them good candidates for protein engineering of new functionality. Our goal is to enhance the efficacy of these mini-proteins by modifying their pharmacological properties in order to extend their use in imaging, diagnostics and therapeutic applications. Using the interaction of three-finger fold toxins with muscarinic and adrenergic receptors as a model, chimeric toxins have been engineered by substituting loops on toxin MT7 by those from toxin MT1. The pharmacological impact of these grafts was examined using binding experiments on muscarinic receptors M1 and M4 and on the α1A-adrenoceptor. Some of the designed chimeric proteins have impressive gain of function on certain receptor subtypes achieving an original selectivity profile with high affinity for muscarinic receptor M1 and α1A-adrenoceptor. Structure-function analysis supported by crystallographic data for MT1 and two chimeras permits a molecular based interpretation of these gains and details the merits of this protein engineering technique. The results obtained shed light on how loop permutation can be used to design new three-finger proteins with original pharmacological profiles.
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Affiliation(s)
- Carole Fruchart-Gaillard
- CEA, iBiTecS, Service d’Ingénierie Moléculaire des Protéines, Laboratoire de Toxinologie Moléculaire et Biotechnologies, Gif-sur-Yvette, France
| | - Gilles Mourier
- CEA, iBiTecS, Service d’Ingénierie Moléculaire des Protéines, Laboratoire de Toxinologie Moléculaire et Biotechnologies, Gif-sur-Yvette, France
| | - Guillaume Blanchet
- CEA, iBiTecS, Service d’Ingénierie Moléculaire des Protéines, Laboratoire de Toxinologie Moléculaire et Biotechnologies, Gif-sur-Yvette, France
- Université Pierre et Marie Curie, Paris, France
| | - Laura Vera
- CEA, iBiTecS, Service d’Ingénierie Moléculaire des Protéines, Laboratoire de Toxinologie Moléculaire et Biotechnologies, Gif-sur-Yvette, France
| | - Nicolas Gilles
- CEA, iBiTecS, Service d’Ingénierie Moléculaire des Protéines, Laboratoire de Toxinologie Moléculaire et Biotechnologies, Gif-sur-Yvette, France
| | - Renée Ménez
- CEA, iBiTecS, Service d’Ingénierie Moléculaire des Protéines, Laboratoire de Toxinologie Moléculaire et Biotechnologies, Gif-sur-Yvette, France
| | - Elodie Marcon
- CEA, iBiTecS, Service d’Ingénierie Moléculaire des Protéines, Laboratoire de Toxinologie Moléculaire et Biotechnologies, Gif-sur-Yvette, France
| | - Enrico A. Stura
- CEA, iBiTecS, Service d’Ingénierie Moléculaire des Protéines, Laboratoire de Toxinologie Moléculaire et Biotechnologies, Gif-sur-Yvette, France
| | - Denis Servent
- CEA, iBiTecS, Service d’Ingénierie Moléculaire des Protéines, Laboratoire de Toxinologie Moléculaire et Biotechnologies, Gif-sur-Yvette, France
- * E-mail:
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16
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Characterization of α2B-adrenoceptor ligand binding in the presence of Muscarinic toxin α and delineation of structural features of receptor binding selectivity. Eur J Pharmacol 2012; 683:63-70. [DOI: 10.1016/j.ejphar.2012.03.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Revised: 03/09/2012] [Accepted: 03/09/2012] [Indexed: 11/24/2022]
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17
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Näreoja K, Louhivuori LM, Akerman KEO, Meriluoto J, Näsman J. Glycosylphosphatidylinositol (GPI)-anchoring of mamba toxins enables cell-restricted receptor silencing. Biochem Biophys Res Commun 2011; 417:93-7. [PMID: 22138651 DOI: 10.1016/j.bbrc.2011.11.062] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Accepted: 11/12/2011] [Indexed: 01/30/2023]
Abstract
Muscarinic toxins (MTs) are snake venom peptides found to selectively target specific subtypes of G-protein-coupled receptors. In here, we have attached a glycosylphosphatidylinositol (GPI) tail to three different toxin molecules and evaluated their receptor-blocking effects in a heterologous expression system. MT7-GPI remained anchored to the cell surface and selectively inhibited M(1) muscarinic receptor signaling expressed in the same cell. To further demonstrate the utility of the GPI tail, we generated MT3- and MTα-like gene sequences and fused these to the signal sequence for GPI attachment. Functional assessment of these membrane-anchored toxins on coexpressed target receptors indicated a prominent antagonistic effect. In ligand binding experiments the GPI-anchored toxins were found to exhibit similar selection profiles among receptor subtypes as the soluble toxins. The results indicate that GPI attachment of MTs and related receptor toxins could be used to assess the role of receptor subtypes in specific organs or even cells in vivo by transgenic approaches.
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Affiliation(s)
- Katja Näreoja
- Department of Biosciences, Biochemistry, Abo Akademi University, Turku, Finland
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Molecular conversion of muscarinic acetylcholine receptor M(5) to muscarinic toxin 7 (MT7)-binding protein. Toxins (Basel) 2011; 3:1393-404. [PMID: 22174976 PMCID: PMC3237002 DOI: 10.3390/toxins3111393] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Revised: 10/11/2011] [Accepted: 11/03/2011] [Indexed: 11/16/2022] Open
Abstract
Muscarinic toxin 7 (MT7) is a mamba venom peptide that binds selectively to the M(1) muscarinic acetylcholine receptor. We have previously shown that the second (ECL2) and third (ECL3) extracellular loops of the M(1) receptor are critically involved in binding the peptide. In this study we used a mutagenesis approach on the M(5) subtype of the receptor family to find out if this possesses a similar structural architecture in terms of toxin binding as the M(1) receptor. An M(5) receptor construct (M(5)-E(175)Y(184)E(474)), mutated at the formerly deciphered critical residues on ECL2 and 3, gained the ability to bind MT7, but with rather low affinity as determined in a functional assay (apparent K(i) = 24 nM; apparent K(i) for M(1) = 0.5 nM). After screening for different domains and residues, we found a specific residue (P(179) to L in M(5)) in the middle portion of ECL2 that was necessary for high affinity binding of MT7 (M(5)-EL(179)YE, apparent K(i) = 0.5 nM). Mutation of P(179) to A confirmed a role for the leucine side chain in the binding of MT7. Together the results reveal new binding interactions between receptors and the MT7 peptide and strengthen the hypothesis that ECL2 sequence is of utmost importance for MT binding to muscarinic receptors.
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Servent D, Blanchet G, Mourier G, Marquer C, Marcon E, Fruchart-Gaillard C. Muscarinic toxins. Toxicon 2011; 58:455-63. [PMID: 21906611 DOI: 10.1016/j.toxicon.2011.08.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Revised: 07/12/2011] [Accepted: 08/08/2011] [Indexed: 12/15/2022]
Abstract
Muscarinic toxins isolated from the venom of Dendroaspis snakes may interact with a high affinity, large selectivity and various functional properties with muscarinic receptors. Therefore, these toxins are invaluable tools for studying the physiological role, molecular functioning and structural organization of the five subtypes of these G-Protein Coupled Receptors. We review the data on the most relevant results dealing with the isolation/identification, mode of action, structure/function and exploitation of these toxins and finally highlight the unresolved issues related to their pharmacological studies.
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Affiliation(s)
- Denis Servent
- CEA, Institute of Biology and Technology, Service d'Ingénierie Moléculaire des Protéines, Gif-sur-Yvette 91191, France.
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