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Dolia J, Das A, Kelkar N. House-warming: Wild king cobra nests have thermal regimes that positively affect hatching success and hatchling size. J Therm Biol 2023; 112:103468. [PMID: 36796913 DOI: 10.1016/j.jtherbio.2023.103468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 01/05/2023] [Accepted: 01/06/2023] [Indexed: 01/09/2023]
Abstract
Incubation temperature in nests of oviparous reptiles affects reproductive success indicators, including hatching time and success, offspring size, fitness, and behaviour. The female king cobra builds an above ground nest to incubate and protect its eggs. However, it is not clear how thermal regimes inside king cobra nests respond to external environmental temperature regimes, especially in subtropical regions that witness high diel and seasonal temperature fluctuations. To better understand the relationship between inside nest temperatures and hatching outcomes for this snake, we monitored the thermal regimes of 25 natural king cobra nests in the subtropical forests of the Western Himalayas in Uttarakhand state, northern India. We hypothesized that inside nest temperatures would be higher than outside (ambient) temperatures and that thermal regimes inside nests would affect hatching success and hatchling size. Internal and external temperatures at nest sites were measured every hour until hatching, via automatic data loggers. We then calculated hatching success of eggs and measured hatchling length and weight. Mean inside nest temperatures were consistently higher by about 3.0 °C than outside environmental temperatures. External temperature reduced with increasing elevation of nest sites and was the best determinant of inside nest temperature, which had a smaller range of variability. Physical characteristics of nests (size and leaf materials used) did not influence nest temperature significantly, but nest size was positively related to clutch size. Mean inside nest temperature was the best predictor of hatching success. Average daily minimum nest temperature, which indicates a possible lower threshold for thermal tolerance by eggs, was also correlated positively with hatching success. Mean daily maximum temperature was a significant predictor of mean length of hatchlings, but not of mean hatchling weight. Our study provides unequivocal evidence for the critical thermal benefits of king cobra nests for increased reproductive success, in subtropical environments with lower and sharply fluctuating temperature regimes.
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Le HQ, Nguyen NTT, Vo TNA, Van Nguyen T, Do KTN, Ho TTC, Nguyen SN, Phan XT, Nguyen DLM, Kieu DN, Ngo HD, Warrell DA. Envenoming by king cobras (Ophiophagus hannah) in Vietnam with cardiac complications and necrotizing fasciitis. Toxicon 2021; 200:127-133. [PMID: 34302855 DOI: 10.1016/j.toxicon.2021.07.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 07/08/2021] [Accepted: 07/12/2021] [Indexed: 11/18/2022]
Abstract
King Cobra (Ophiophagus hannah) bite is well-known for its potentially fatal neurotoxicity. However, fatalities still occur, despite specific antivenom and respiratory support. Cardiovascular disturbances, which have attracted little attention in published reports of O. hannah envenoming, could contribute to fatality. We present two cases of confirmed O. hannah envenoming in Southern Vietnam in which there were cardiac abnormalities including arrhythmias and electrocardiographic changes, as well as elevated markers of myocardial damage. Cardiac pacing was required. One patient developed critical multi-organ dysfunctions partly explained by extensive necrotizing fasciitis/myositis originating from an Aeromonas sobria wound infection. This resulted in rhabdomyolysis, disseminated intravascular coagulation and acute kidney injury. Specific antivenom reversed neurotoxic effects of envenoming. Additional therapeutic interventions included antibiotics, surgical debridement, continuous renal replacement therapy and therapeutic plasma exchange. Both patients eventually made full recoveries. Apart from the critical problem of rapidly evolving and severe neurotoxicity, our case reports also emphasises the risk of cardiotoxic envenoming, and the complications of an overwhelming secondary bacterial wound infection. We suggest a practical approach to diagnosis and management.
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Affiliation(s)
- Hung Quoc Le
- Department of Tropical Diseases, Cho Ray Hospital, 201B Nguyen Chi Thanh, District 5, Ho Chi Minh City, Viet Nam
| | - Ngan Thi Thuy Nguyen
- Department of Tropical Diseases, Cho Ray Hospital, 201B Nguyen Chi Thanh, District 5, Ho Chi Minh City, Viet Nam; Oxford University Clinical Research Unit, 764 Vo Van Kiet, Quan 5, Ho Chi Minh City, Viet Nam.
| | - Tho Ngoc Anh Vo
- Department of Tropical Diseases, Cho Ray Hospital, 201B Nguyen Chi Thanh, District 5, Ho Chi Minh City, Viet Nam
| | - Thuan Van Nguyen
- Department of Tropical Diseases, Cho Ray Hospital, 201B Nguyen Chi Thanh, District 5, Ho Chi Minh City, Viet Nam
| | - Khanh Thi Ngoc Do
- Department of Tropical Diseases, Cho Ray Hospital, 201B Nguyen Chi Thanh, District 5, Ho Chi Minh City, Viet Nam
| | - Thanh Thi Chi Ho
- Department of Tropical Diseases, Cho Ray Hospital, 201B Nguyen Chi Thanh, District 5, Ho Chi Minh City, Viet Nam
| | - Sang Ngoc Nguyen
- Department of Tropical Diseases, Cho Ray Hospital, 201B Nguyen Chi Thanh, District 5, Ho Chi Minh City, Viet Nam
| | - Xuan Thi Phan
- Central Intensive Care Unit, Cho Ray Hospital, 201B Nguyen Chi Thanh, District 5, Ho Chi Minh City, Viet Nam
| | - Duy Ly Minh Nguyen
- Central Intensive Care Unit, Cho Ray Hospital, 201B Nguyen Chi Thanh, District 5, Ho Chi Minh City, Viet Nam
| | - Dung Ngoc Kieu
- Department of Arrhythmia, Cho Ray Hospital, 201B Nguyen Chi Thanh, District 5, Ho Chi Minh City, Viet Nam
| | - Hiep Duc Ngo
- Department of Burn and Plastic Surgery, Cho Ray Hospital, 201B Nguyen Chi Thanh, District 5, Ho Chi Minh City, Viet Nam
| | - David A Warrell
- Nuffield Department of Clinical Medicine, University of Oxford, UK
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Lertwanakarn T, Suntravat M, Sanchez EE, Boonhoh W, Solaro RJ, Wolska BM, Martin JL, de Tombe PP, Tachampa K. Suppression of cardiomyocyte functions by β-CTX isolated from the Thai king cobra ( Ophiophagus hannah) venom via an alternative method. J Venom Anim Toxins Incl Trop Dis 2020; 26:e20200005. [PMID: 32742278 PMCID: PMC7375408 DOI: 10.1590/1678-9199-jvatitd-2020-0005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 06/16/2020] [Indexed: 12/20/2022] Open
Abstract
Background Beta-cardiotoxin (β-CTX), the three-finger toxin isolated from king cobra (Ophiophagus hannah) venom, possesses β-blocker activity as indicated by its negative chronotropy and its binding property to both β-1 and β-2 adrenergic receptors and has been proposed as a novel β-blocker candidate. Previously, β-CTX was isolated and purified by FPLC. Here, we present an alternative method to purify this toxin. In addition, we tested its cytotoxicity against different mammalian muscle cell types and determined the impact on cardiac function in isolated cardiac myocyte so as to provide insights into the pharmacological action of this protein. Methods β-CTX was isolated from the crude venom of the Thai king cobra using reverse-phased and cation exchange HPLC. In vitro cellular viability MTT assays were performed on mouse myoblast (C2C12), rat smooth muscle (A7r5), and rat cardiac myoblast (H9c2) cells. Cell shortening and calcium transient dynamics were recorded on isolated rat cardiac myocytes over a range of β-CTX concentration. Results Purified β-CTX was recovered from crude venom (0.53% w/w). MTT assays revealed 50% cytotoxicity on A7r5 cells at 9.41 ± 1.14 µM (n = 3), but no cytotoxicity on C2C12 and H9c2 cells up to 114.09 µM. β-CTX suppressed the extend of rat cardiac cell shortening in a dose-dependent manner; the half-maximal inhibition concentration was 95.97 ± 50.10 nM (n = 3). In addition, the rates of cell shortening and re-lengthening were decreased in β-CTX treated myocytes concomitant with a prolongation of the intracellular calcium transient decay, indicating depression of cardiac contractility secondary to altered cardiac calcium homeostasis. Conclusion We present an alternative purification method for β-CTX from king cobra venom. We reveal cytotoxicity towards smooth muscle and depression of cardiac contractility by this protein. These data are useful to aid future development of pharmacological agents derived from β-CTX.
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Affiliation(s)
- Tuchakorn Lertwanakarn
- Department of Physiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand
| | - Montamas Suntravat
- National Natural Toxins Research Center, Texas A&M University-Kingsville, Kingsville, TX, USA.,Department of Chemistry, Texas A&M University-Kingsville, Kingsville, TX, USA
| | - Elda E Sanchez
- National Natural Toxins Research Center, Texas A&M University-Kingsville, Kingsville, TX, USA.,Department of Chemistry, Texas A&M University-Kingsville, Kingsville, TX, USA
| | - Worakan Boonhoh
- Department of Physiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand
| | - R John Solaro
- Department of Physiology and Biophysics, University of Illinois at Chicago, IL, USA
| | - Beata M Wolska
- Department of Physiology and Biophysics, University of Illinois at Chicago, IL, USA.,Department of Medicine, University of Illinois at Chicago, IL, USA
| | - Jody L Martin
- Department of Physiology and Biophysics, University of Illinois at Chicago, IL, USA
| | - Pieter P de Tombe
- Department of Physiology and Biophysics, University of Illinois at Chicago, IL, USA
| | - Kittipong Tachampa
- Department of Physiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand
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Liu W, Xu Y, Li Z, Fan J, Yang Y. Genome-wide mining of microsatellites in king cobra (Ophiophagus hannah) and cross-species development of tetranucleotide SSR markers in Chinese cobra (Naja atra). Mol Biol Rep 2019; 46:6087-6098. [PMID: 31502192 DOI: 10.1007/s11033-019-05044-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 08/22/2019] [Indexed: 12/13/2022]
Abstract
The complete genome sequence provides the opportunity for genome-wide and coding region analysis of SSRs in the king cobra and for cross-species identification of microsatellite markers in the Chinese cobra. In the Ophiophagus hannah genome, tetranucleotide repeats (38.03%) were the most abundant category, followed by dinucleotides (23.03%), pentanucleotides (13.07%), mononucleotides (11.78%), trinucleotides (11.49%) and hexanucleotides (2.6%). Twenty predominant motifs in the O. hannah genome were (A)n (C)n, (AC)n, (AG)n, (AT)n, (AGG)n, (AAT)n, (AAG)n, (AAC)n, (ATG)n, (ATAG)n, (AAGG)n, (ATCT)n, (CCTT)n, (ATTT)n, (AAAT)n, (AATAG)n, (ATTCT)n, (ATATGT)n, (AGATAT)n. In total, 4344 SSRs were found in coding sequences (CDSs). Tetranucleotides (52.79%) were the most abundant microsatellite type in CDS, followed by trinucleotides (28.50%), dinucleotides (11.02%), pentanucleotides (4.42%), mononucleotides (1.77%), and hexanucleotides (1.50%). A total of 984 CDSs containing microsatellites were assigned 11152 Gene Ontology (GO) functional terms. Gene Ontology (GO) analysis demonstrated that cellular process, cell and binding were the most frequent GO terms in biological process, cellular component and molecular function, respectively. Thirty-two novel highly polymorphic (PIC > 0.5) SSR markers for Naja atra were developed from cross-species amplification based on the tetranucleotide microsatellite sequences in the king cobra genome. The number of alleles (NA) per locus had between 3 and 11 alleles with an average of 6.5, the polymorphism information content (PIC) value ranged from 0.521 to 0.858 (average = 0.707), the observed heterozygosity (Ho) of 32 microsatellite loci ranged from 0.292 to 0.875 (mean = 0.678), the expected heterozygosity (HE) ranged from 0.561 to 0.889 (average = 0.761), and 3 microsatellite loci exhibited statistically significant departure from Hardy-Weinberg equilibrium (HWE) after Bonferroni correction (p < 0.003).
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Affiliation(s)
- Wencong Liu
- Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, China
- College of Materials and Chemistry & Chemical Engineering, Chengdu University of Technology, Chengdu, 610059, China
| | - Yongtao Xu
- College of Forestry, Jiangxi Agricultural University, Nanchang, 330045, China
| | - Zekun Li
- College of Materials and Chemistry & Chemical Engineering, Chengdu University of Technology, Chengdu, 610059, China
| | - Jun Fan
- College of Materials and Chemistry & Chemical Engineering, Chengdu University of Technology, Chengdu, 610059, China
| | - Yi Yang
- Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, China.
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Chang HC, Tsai TS, Tsai IH. Functional proteomic approach to discover geographic variations of king cobra venoms from Southeast Asia and China. J Proteomics 2013; 89:141-53. [PMID: 23796489 DOI: 10.1016/j.jprot.2013.06.012] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Revised: 06/10/2013] [Accepted: 06/13/2013] [Indexed: 11/21/2022]
Abstract
UNLABELLED This study deciphers the geographic variations of king cobra (Ophiophagus hannah) venom using functional proteomics. Pooled samples of king cobra venom (abbreviated as Ohv) were obtained from Indonesia, Malaysia, Thailand, and two provinces of China, namely Guangxi and Hainan. Using two animal models to test and compare the lethal effects, we found that the Chinese Ohvs were more fatal to mice, while the Southeast Asian Ohvs were more fatal to lizards (Eutropis multifasciata). Various phospholipases A2 (PLA2s), three-finger toxins (3FTxs) and Kunitz-type inhibitors were purified from these Ohvs and compared. Besides the two Chinese Ohv PLA2s with known sequences, eight novel PLA2s were identified from the five Ohv samples and their antiplatelet activities were compared. While two 3FTxs (namely oh-55 and oh-27) were common in all the Ohvs, different sets of 3FTx markers were present in the Chinese and Southeast Asian Ohvs. All the Ohvs contain the Kunitz inhibitor, OH-TCI, while only the Chinese Ohvs contain the inhibitor variant, Oh11-1. Relative to the Chinese Ohvs which contained more phospholipases, the Southeast Asian Ohvs had higher metalloproteinase, acetylcholine esterase, and alkaline phosphatase activities. BIOLOGICAL SIGNIFICANCE Remarkable variations in five king cobra geographic samples reveal fast evolution and dynamic translational regulation of the venom which probably adapted to different prey ecology as testified by the lethal tests on mice and lizards. Our results predict possible variations of the king cobra envenoming to human and the importance of using local antivenin for snakebite treatment.
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