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1.
Toxins (Basel) ; 14(8)2022 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-36006190

RESUMO

Snake venom is an adaptive ecological trait that has evolved primarily as a form of prey subjugation. Thus, the selection pressure for toxin diversification is exerted by the prey's physiological targets, with this pressure being particularly acute for specialist feeders, such as the King Cobra species, all of which are snake-prey specialists. However, while extensive research has been undertaken to elucidate key amino acids that guide toxin structure-activity relationships, reciprocal investigations into the specific sites guiding prey-lineage selective effects have been lacking. This has largely been due to the lack of assay systems amenable to systematic amino acid replacements of targeted proteins in the prey's physiological pathways. To fill this knowledge gap, we used a recently described approach based upon mimotope peptides corresponding to the orthosteric site of nicotinic acetylcholine receptor alpha-1 subunits, a major binding site for snake venom neurotoxins that cause flaccid paralysis. We investigated the venoms of four different types of King Cobra (Cambodian, Javan, Malaysian, and Thai). This approach allowed for the determination of the key amino acid positions in King Cobra snake prey that are selectively bound by the toxins, whereby replacing these amino acids in the snake-prey orthosteric site with those from lizards or rats resulted in a significantly lower level of binding by the venoms, while conversely replacing the lizard or rat amino acids with those from the snake at that position increased the binding. By doing such, we identified three negatively charged amino acids in the snake orthosteric site that are strongly bound by the positively charged neurotoxic three-finger toxins found in King Cobra venom. This study, thus, sheds light on the selection pressures exerted by a specialist prey item for the evolution of lineage-selective toxins.


Assuntos
Colubridae , Lagartos , Receptores Nicotínicos , Toxinas Biológicas , Aminoácidos/metabolismo , Animais , Colubridae/metabolismo , Venenos Elapídicos/metabolismo , Venenos Elapídicos/toxicidade , Elapidae/metabolismo , Lagartos/metabolismo , Ophiophagus hannah/metabolismo , Ratos , Receptores Nicotínicos/metabolismo , Venenos de Serpentes/química , Toxinas Biológicas/metabolismo
2.
Mol Phylogenet Evol ; 165: 107300, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34474153

RESUMO

In widespread species, the diverse ecological conditions in which the populations occur, and the presence of many potential geographical barriers through their range are expected to have created ample opportunities for the evolution of distinct, often cryptic lineages. In this work, we tested for species boundaries in one such widespread species, the king cobra, Ophiophagus hannah (Cantor, 1836), a largely tropical elapid snake distributed across the Oriental realm. Based on extensive geographical sampling across most of the range of the species, we initially tested for candidate species (CS) using Maximum-Likelihood analysis of mitochondrial genes. We then tested the resulting CS using both morphological data and sequences of three single-copy nuclear genes. We used snapclust to determine the optimal number of clusters in the nuclear dataset, and Bayesian Phylogenetics and Phylogeography (BPP) to test for likely species status. We used non-metric multidimensional scaling (nMDS) analysis for discerning morphological separation. We recovered four independently evolving, geographically separated lineages that we consider Confirmed Candidate Species: (1) Western Ghats lineage; (2) Indo-Chinese lineage (3) Indo-Malayan lineage; (4) Luzon Island lineage, in the Philippine Archipelago. We discuss patterns of lineage divergence, particularly in the context of low morphological divergence, and the conservation implications of recognizing several endemic king cobra lineages.


Assuntos
DNA , Ophiophagus hannah , Animais , Teorema de Bayes , Filipinas , Filogenia , Piridazinas
3.
Toxicon ; 200: 127-133, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34302855

RESUMO

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.


Assuntos
Fasciite Necrosante , Ophiophagus hannah , Aeromonas , Animais , Venenos Elapídicos , Humanos , Vietnã
4.
Sci Rep ; 11(1): 7271, 2021 03 31.
Artigo em Inglês | MEDLINE | ID: mdl-33790309

RESUMO

Facultative parthenogenesis (FP) is widespread in the animal kingdom. In vertebrates it was first described in poultry nearly 70 years ago, and since then reports involving other taxa have increased considerably. In the last two decades, numerous reports of FP have emerged in elasmobranch fishes and squamate reptiles (lizards and snakes), including documentation in wild populations of both clades. When considered in concert with recent evidence of reproductive competence, the accumulating data suggest that the significance of FP in vertebrate evolution has been largely underestimated. Several fundamental questions regarding developmental mechanisms, nonetheless, remain unanswered. Specifically, what is the type of automixis that underlies the production of progeny and how does this impact the genomic diversity of the resulting parthenogens? Here, we addressed these questions through the application of next-generation sequencing to investigate a suspected case of parthenogenesis in a king cobra (Ophiophagus hannah). Our results provide the first evidence of FP in this species, and provide novel evidence that rejects gametic duplication and supports terminal fusion as a mechanism underlying parthenogenesis in snakes. Moreover, we precisely estimated heterozygosity in parthenogenetic offspring and found appreciable retained genetic diversity that suggests that FP in vertebrates has underappreciated evolutionary significance.


Assuntos
Evolução Molecular , Repetições de Microssatélites , Ophiophagus hannah/genética , Partenogênese , Animais , Estudo de Associação Genômica Ampla
5.
PLoS One ; 15(12): e0242826, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33296389

RESUMO

Identifying individuals with natural markings is increasing in popularity to non-invasively support population studies. However, applying natural variation among individuals requires careful evaluation among target species, snakes for example have little validation of such methods. Here we introduce a mark-free identification method for King Cobras (Ophiophagus hannah) from the Sakaerat Biosphere Reserve, in northeast Thailand using both subcaudal scale pholidosis (scale arrangement and number) and unique ventral body markings to distinguish individuals. This project aims to evaluate the impact of observer error on individual identification. Observers of varying expertise, will distinguish between King Cobra individuals using identifying photographs from a previous study. We will ask randomly assigned observers to distinguish individuals via: 1) subcaudal pholidosis, 2) ventral body markings, and 3) combination of both measures. Using Bayesian logistic regression, we will assess the probability observers correctly distinguish individuals. Based on exploratory observations, we hypothesise that there will be a high probability of correct identifications using subcaudal pholidosis and ventral body markings. We aim to stimulate other studies implementing identification techniques for scrutinous assessment of such methods, in order to avoid subsequent errors during long-term population studies.


Assuntos
Comportamento Animal , Ophiophagus hannah , Fotografação , Animais , Variações Dependentes do Observador , Ophiophagus hannah/classificação , Tailândia
6.
PLoS Negl Trop Dis ; 14(11): e0008873, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-33253321

RESUMO

Bungarus multicinctus is the most venomous snake distributed in China and neighboring countries of Myanmar, Laos, north Vietnam and Thailand. The high mortality rate of B. multicinctus envenomation is attributed to the lethal components of α-, ß-, γ- and κ- bungarotoxins contained in the venom. Although anti-B. multicinctus sera were produced in Shanghai, Taiwan and Vietnam, the most widely clinic used product was term as B. multicinctus antivenin and manufactured by Shanghai Serum Bio-technology Co. Ltd. In the present investigation, high purity α-, ß- and γ-bungarotoxins were separately isolated from B. multicinctus crude venom. Rabbit anti- α-, ß- and γ-bungarotoxin antisera were prepared by common methods, respectively. LD50 values of α-, ß- and γ-bungarotoxins were systematically determined via three administration pathways (intraperitoneal, intramuscular and intravenous injections) in Kunming mice. LD50 values of ß-bungarotoxin were closely related with injection routines but those of both α- and γ-bungarotoxins were not dependent on the injection routines. Commercial B. multicinctus antivenin showed strong immunoreaction with high molecular weight fractions of the B. multicinctus but weakly recognized low molecular weight fractions like α- and γ-bungarotoxins. Although B. multicinctus antivenin showed immunoreaction with high molecular weight fractions of Bungarus fasciatus, Naja atra, Ophiophagus hannah venoms but the antivenin only demonstrated animal protection efficacy against O. hannah venom. These results indicated that the high molecular weight fractions of the O. hannah played an important role in venom lethality but those of B. fasciatus and N. atra did not have such a role.


Assuntos
Antivenenos/imunologia , Bungarotoxinas/imunologia , Venenos Elapídicos/imunologia , Soros Imunes/imunologia , Animais , Bungarotoxinas/química , Bungarotoxinas/toxicidade , Bungarus , China , Venenos Elapídicos/química , Venenos Elapídicos/toxicidade , Dose Letal Mediana , Masculino , Camundongos , Testes de Neutralização , Ophiophagus hannah , Coelhos
8.
Acta Trop ; 203: 105311, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31862461

RESUMO

The wide distribution of king cobra (Ophiophagus hannah), a medically important venomous snake in Asia could be associated with geographical variation in the toxicity and antigenicity of the venom. This study investigated the lethality of king cobra venoms (KCV) from four geographical locales (Malaysia, Thailand, Indonesia, China), and the immunological binding as well as in vivo neutralization activities of three antivenom products (Thai Ophiophagus hannah monovalent antivenom, OHMAV; Indonesian Serum Anti Bisa Ular, SABU; Chinese Naja atra monovalent antivenom, NAMAV) toward the venoms. The Indonesian and Chinese KCV were more lethal (median lethal dose, LD50 ~0.5 µg/g) than those from Malaysia and Thailand (LD50 ~1.0 µg/g). The antivenoms, composed of F(ab)'2, were variably immunoreactive toward the KCV from all locales, with OHMAV exhibited the highest immunological binding activity. In mice, OHMAV neutralized the neurotoxic lethality of Thai KCV most effectively (normalized potency = 118 mg venom neutralized per g antivenom) followed by Malaysian, Indonesian and Chinese KCV. In comparison, the hetero-specific SABU was remarkably less potent by at least 6 to10 folds, whereas NAMAV appeared to be non-effective. The finding supports that a specific king cobra antivenom is needed for the effective treatment of king cobra envenomation in each region.


Assuntos
Antivenenos/imunologia , Antivenenos/uso terapêutico , Venenos Elapídicos/imunologia , Venenos Elapídicos/toxicidade , Animais , China , Indonésia , Dose Letal Mediana , Malásia , Camundongos , Ophiophagus hannah , Tailândia
9.
Front Public Health ; 8: 608765, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33643982

RESUMO

A novel severe acute respiratory syndrome coronavirus, SARS-CoV-2, emerged in China in December 2019 and spread worldwide, causing more than 1.3 million deaths in 11 months. Similar to the human SARS-CoV, SARS-CoV-2 shares strong sequence homologies with a sarbecovirus circulating in Rhinolophus affinis bats. Because bats are expected to be able to transmit their coronaviruses to intermediate animal hosts that in turn are a source of viruses able to cross species barriers and infect humans (so-called spillover model), the identification of an intermediate animal reservoir was the subject of intense researches. It was claimed that a reptile (Ophiophagus hannah) was the intermediate host. This hypothesis was quickly ruled out and replaced by the pangolin (Manis javanica) hypothesis. Yet, pangolin was also recently exonerated from SARS-CoV-2 transmission to humans, leaving other animal species as presumed guilty. Guided by the spillover model, several laboratories investigated in silico the species polymorphism of the angiotensin I converting enzyme 2 (ACE2) to find the best fits with the SARS-CoV-2 spike receptor-binding site. Following the same strategy, we used multi-sequence alignment, 3-D structure analysis, and electrostatic potential surface generation of ACE2 variants to predict their binding capacity to SARS-CoV-2. We report evidence that such simple in silico investigation is a powerful tool to quickly screen which species are potentially susceptible to SARS-CoV-2. However, possible receptor binding does not necessarily lead to successful replication in host. Therefore, we also discuss here the limitations of these in silico approaches in our quest on the origins of COVID-19 pandemic.


Assuntos
COVID-19/imunologia , COVID-19/patologia , Especificidade de Hospedeiro/genética , Receptores de Angiotensina/genética , Origem de Replicação , SARS-CoV-2/genética , SARS-CoV-2/patogenicidade , Animais , China , Quirópteros/virologia , Predisposição Genética para Doença , Humanos , Ophiophagus hannah/virologia , Pandemias , Pangolins/virologia , Polimorfismo de Nucleotídeo Único
10.
J. venom. anim. toxins incl. trop. dis ; 26: e20200005, 2020. tab, graf
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1135147

RESUMO

Beta-cardiotoxin (ß-CTX), the three-finger toxin isolated from king cobra (Ophiophagus hannah) venom, possesses ß-blocker activity as indicated by its negative chronotropy and its binding property to both ß-1 and ß-2 adrenergic receptors and has been proposed as a novel ß-blocker candidate. Previously, ß-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: ß-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 ß-CTX concentration. Results: Purified ß-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. ß-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 ß-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 ß-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 ß-CTX.(AU)


Assuntos
Animais , Charibdotoxina/isolamento & purificação , Miócitos Cardíacos , Proteínas Cardiotóxicas de Elapídeos , Venenos Elapídicos , Cardiotoxinas , Ophiophagus hannah , Supressão , Citotoxicidade Imunológica
11.
Toxins (Basel) ; 11(10)2019 10 16.
Artigo em Inglês | MEDLINE | ID: mdl-31623073

RESUMO

The binding of compounds to nicotinic acetylcholine receptors is of great interest in biomedical research. However, progress in this area is hampered by the lack of a high-throughput, cost-effective, and taxonomically flexible platform. Current methods are low-throughput, consume large quantities of sample, or are taxonomically limited in which targets can be tested. We describe a novel assay which utilizes a label-free bio-layer interferometry technology, in combination with adapted mimotope peptides, in order to measure ligand binding to the orthosteric site of nicotinic acetylcholine receptor alpha-subunits of diverse organisms. We validated the method by testing the evolutionary patterns of a generalist feeding species (Acanthophis antarcticus), a fish specialist species (Aipysurus laevis), and a snake specialist species (Ophiophagus hannah) for comparative binding to the orthosteric site of fish, amphibian, lizard, snake, bird, marsupial, and rodent alpha-1 nicotinic acetylcholine receptors. Binding patterns corresponded with diet, with the Acanthophis antarcticus not showing bias towards any particular lineage, while Aipysurus laevis showed selectivity for fish, and Ophiophagus hannah a selectivity for snake. To validate the biodiscovery potential of this method, we screened Acanthophis antarcticus and Tropidolaemus wagleri venom for binding to human alpha-1, alpha-2, alpha-3, alpha-4, alpha-5, alpha-6, alpha-7, alpha-9, and alpha-10. While A. antarcticus was broadly potent, T. wagleri showed very strong but selective binding, specifically to the alpha-1 target which would be evolutionarily selected for, as well as the alpha-5 target which is of major interest for drug design and development. Thus, we have shown that our novel method is broadly applicable for studies including evolutionary patterns of venom diversification, predicting potential neurotoxic effects in human envenomed patients, and searches for novel ligands of interest for laboratory tools and in drug design and development.


Assuntos
Receptores Nicotínicos/metabolismo , Venenos de Serpentes , Animais , Sítios de Ligação , Aves , Colubridae , Elapidae , Ensaios de Triagem em Larga Escala , Humanos , Ligantes , Lagartos , Marsupiais , Ophiophagus hannah , Peptídeos/metabolismo , Filogenia , Roedores , Especificidade da Espécie
12.
Mol Biol Rep ; 46(6): 6087-6098, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31502192

RESUMO

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).


Assuntos
Repetições de Microssatélites/genética , Naja naja/genética , Ophiophagus hannah/genética , Alelos , Animais , Loci Gênicos/genética , Marcadores Genéticos/genética , Estudo de Associação Genômica Ampla/métodos , Polimorfismo Genético/genética , Análise de Sequência de DNA/métodos
13.
Protein J ; 38(5): 565-575, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31278531

RESUMO

The biochemical properties and biological activities of the venom from three individual Ophiophagus hannah (King cobra) specimens was compared. The toxicity against mice, the cytotoxicity against five cell lines, and the antioxidant activity were measured. The KV2 venom showed a higher cytotoxicity than the KV6 and the non-cytotoxic KV9 venoms. Comparative analysis of the O. hannah venom proteins was performed after 2-dimensional (2-D) denaturing gel electrophoresis and reverse phase high performance liquid chromatography (RP-HPLC). 2-D analysis by isoelectric focusing (IEF) Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) resolution of the venoms revealed significant differences between all three venoms, with most spots being unique to that venom. Only 2 out of the 13-16 distinct spots were common to all three venoms, and four spots were common to KV6 and KV9. KV2 had the highest proportion of low molecular mass spots, and KV6 and KV9 appeared more related to each other than to KV9. From peptide mass mapping by matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and MASCOT-based amino acid sequence database searching, the two venom proteins that were common to all three specimens are likely to be ophanin and acidic phospholipase A2 (PLA2), whilst the proteins unique to the cytotoxic KV2 venom, included three other PLA2 proteins. The RP-HPLC pattern of KV2 was different from the other two venoms with a higher protein concentration eluting in the 31-41% (v/v) acetonitrile (ACN) fraction than for the other two venoms.


Assuntos
Venenos Elapídicos/química , Venenos Elapídicos/farmacologia , Ophiophagus hannah , Proteínas de Répteis/química , Proteínas de Répteis/farmacologia , Animais , Antineoplásicos/química , Antineoplásicos/metabolismo , Antineoplásicos/farmacologia , Antioxidantes/química , Antioxidantes/metabolismo , Antioxidantes/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Venenos Elapídicos/metabolismo , Eletroforese em Gel de Poliacrilamida , Humanos , Ophiophagus hannah/metabolismo , Proteínas de Répteis/metabolismo , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
14.
Protein Sci ; 28(5): 952-963, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30891862

RESUMO

ß-Cardiotoxin is a novel member of the snake venom three-finger toxin (3FTX) family. This is the first exogenous protein to antagonize ß-adrenergic receptors and thereby causing reduction in heart rates (bradycardia) when administered into animals, unlike the conventional cardiotoxins as reported earlier. 3FTXs are stable all ß-sheet peptides with 60-80 amino acid residues. Here, we describe the three-dimensional crystal structure of ß-cardiotoxin together with the identification of a molten globule intermediate in the unfolding pathway of this protein. In spite of the overall structural similarity of this protein with conventional cardiotoxins, there are notable differences observed at the loop region and in the charge distribution on the surface, which are known to be critical for cytolytic activity of cardiotoxins. The molten globule intermediate state present in the thermal unfolding pathway of ß-cardiotoxin was however not observed during the chemical denaturation of the protein. Interestingly, circular dichroism (CD) and NMR studies revealed the presence of α-helical secondary structure in the molten globule intermediate. These results point to substantial conformational plasticity of ß-cardiotoxin, which might aid the protein in responding to the sometimes conflicting demands of structure, stability, and function during its biological lifetime.


Assuntos
Cardiotoxinas/química , Ophiophagus hannah/metabolismo , Venenos de Serpentes/metabolismo , Animais , Dicroísmo Circular , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Desnaturação Proteica , Dobramento de Proteína , Estrutura Secundária de Proteína , Venenos de Serpentes/química
15.
J Zoo Wildl Med ; 49(4): 1061-1063, 2018 12 13.
Artigo em Inglês | MEDLINE | ID: mdl-30592920

RESUMO

Feces collected from a wild-caught, young adult king cobra ( Ophiophagus hannah) were repeatedly positive for Cryptosporidium on both direct immunofluorescent antibody (DFA) and polymerase chain reaction (PCR), and sequencing identified the organism as Cryptosporidium serpentis. Infection was subclinical, as the snake was in good body condition and active, and readily consumed dead rats that were scented with snake skin. A course of paromomycin, inserted in feeder rats, was initiated at 360 mg/kg, orally, twice weekly for 6 wk. Feces collected at the end of treatment were negative for Cryptosporidium on PCR, as were feces collected 3 wk, 6 mo, 12 mo, and 18 mo later. At higher dosages, paromomycin may prove useful and may be curative for early gastric and intestinal cryptosporidiosis in squamate reptiles.


Assuntos
Antiprotozoários/uso terapêutico , Criptosporidiose/tratamento farmacológico , Cryptosporidium/isolamento & purificação , Ophiophagus hannah , Paromomicina/uso terapêutico , Animais , Animais de Zoológico , Criptosporidiose/parasitologia , Resultado do Tratamento
16.
Toxins (Basel) ; 10(11)2018 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-30373186

RESUMO

Calloselasma rhodostoma (CR) and Ophiophagus hannah (OH) are two medically important snakes found in Malaysia. While some studies have described the biological properties of these venoms, feeding and environmental conditions also influence the concentration and distribution of snake venom toxins, resulting in variations in venom composition. Therefore, a combined proteomic approach using shotgun and gel filtration chromatography, analyzed by tandem mass spectrometry, was used to examine the composition of venoms from these Malaysian snakes. The analysis revealed 114 proteins (15 toxin families) and 176 proteins (20 toxin families) in Malaysian Calloselasma rhodostoma and Ophiophagus hannah species, respectively. Flavin monoamine oxidase, phospholipase A2, phosphodiesterase, snake venom metalloproteinase, and serine protease toxin families were identified in both venoms. Aminopeptidase, glutaminyl-peptide cyclotransferase along with ankyrin repeats were identified for the first time in CR venom, and insulin, c-type lectins/snaclecs, hepatocyte growth factor, and macrophage colony-stimulating factor together with tumor necrosis factor were identified in OH venom for the first time. Our combined proteomic approach has identified a comprehensive arsenal of toxins in CR and OH venoms. These data may be utilized for improved antivenom production, understanding pathological effects of envenoming, and the discovery of biologically active peptides with medical and/or biotechnological value.


Assuntos
Venenos de Crotalídeos/química , Venenos Elapídicos/química , Proteínas de Répteis/análise , Animais , Crotalinae , Malásia , Ophiophagus hannah , Proteômica
18.
PLoS One ; 13(9): e0203449, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30226846

RESUMO

Home range estimators are a critical component for understanding animal spatial ecology. The choice of home range estimator in spatial ecology studies can significantly influence management and conservation actions, as different methods lead to vastly different interpretations of movement patterns, habitat selection, as well as home range requirements. Reptile studies in particular have struggled to reach a consensus on the appropriate home range estimators to use, and species with cryptic behavior make home range assessment difficult. We applied dynamic Brownian Bridge Movement Models (dBBMMs) to radio-telemetry data from Ophiophagus hannah, a wide-ranging snake species. We used two focal individuals at different life stages (one juvenile male and one adult male) and sought to identify whether the method would accurately represent both their home range and movement patterns. To assess the suitability of dBBMMs, we compared this novel method with traditional home range estimation methods: minimum convex polygons (MCP) and Kernel density estimators (KDE). Both KDE and MCP incorporated higher levels of Type I and Type II errors, which would lead to biases in our understanding of this species space-use and habitat selection. Although these methods identified some general spatial-temporal patterns, dBBMMs were more efficient at detecting movement corridors and accurately representing long-term shelters sites, showing an improvement over methods traditionally favored in reptile studies. The additional flexibility of the dBBMM approach in providing insight into movement patterns can help further improve conservation and management actions. Additionally, our results suggest that dBBMMs may be more widely applicable in studies that rely on VHF telemetry and not limited to studies employing GPS tags.


Assuntos
Migração Animal/fisiologia , Modelos Biológicos , Ophiophagus hannah/fisiologia , Animais
19.
Zool Res ; 39(2): 87-96, 2018 03 18.
Artigo em Inglês | MEDLINE | ID: mdl-29515090

RESUMO

Cationic antimicrobial peptides (AMPs) are considered as important candidate therapeutic agents, which exert potent microbicidal properties against bacteria, fungi and some viruses. Based on our previous findings king cobra cathelicidin (OH-CATH) is a 34-amino acid peptide that exerts strong antibacterial and weak hemolytic activity. The aim of this research is to evaluate the efficacy of both OH-CATH30 and its analog D-OH-CATH30 against clinical isolates comparing with routinely utilized antibiotics in vitro. In this study, 584 clinical isolates were tested (spanning 2013-2016) and the efficacy of the candidate peptides and antibiotics were determined by a broth microdilution method according to the CLSI guidelines. Among the 584 clinical isolates, 85% were susceptible to OH-CATH30 and its analogs. Both L- and D-OH-CATH30 showed higher efficacy against (toward) Gram-positive bacteria and stronger antibacterial activity against nearly all Gram-negative bacteria tested compare with antibiotics. The highest bactericidal activity was detected against Acinetobacter spp., including multi-drug-resistant Acinetobacter baumannii (MRAB) and methicillin-resistant Staphylococcus aureus (MRSA). The overall efficacy of OH-CATH30 and its analogs was higher than that of the 9 routinely used antibiotics. OH-CATH30 is a promising candidate drug for the treatment of a wide variety of bacterial infections which are resistant to many routinely used antimicrobial agents.


Assuntos
Anti-Infecciosos/uso terapêutico , Peptídeos Catiônicos Antimicrobianos/uso terapêutico , Venenos Elapídicos/uso terapêutico , Animais , Anti-Infecciosos/isolamento & purificação , Peptídeos Catiônicos Antimicrobianos/isolamento & purificação , Farmacorresistência Bacteriana , Venenos Elapídicos/isolamento & purificação , Testes de Sensibilidade Microbiana , Ophiophagus hannah
20.
Multimedia | Recursos Multimídia | ID: multimedia-2155

RESUMO

No último domingo (11), a Secretaria Municipal da Saúde realizou uma ação especial para o Dia dos Namorados na avenida Paulista. Confira como foi!


Assuntos
Ophiophagus hannah
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