Natural Snake Research Articles

Combined Soft Grasping and Crawling Locomotor Robot for Exterior Navigation of Tubular Structures

This paper presents the design, development, and testing of a robot that combines soft-body grasping and crawling locomotion to navigate tubular objects. Inspired by the natural snakes’ climbing locomotion of tubular objects, the soft robot includes proximal and distal modules with radial expansion/contraction for grasping around the objects and a longitudinal contractile–expandable driving module in-between for providing a bi-directional crawling movement along the length of the object. The robot’s grasping modules are made of fabrics, and the crawling module is made of an extensible pneumatic soft actuator (ePSA). Conceptual designs and CAD models of the robot parts, textile-based inflatable structures, and pneumatic driving mechanisms were developed. The mechanical parts were fabricated using advanced and conventional manufacturing techniques. An Arduino-based electro-pneumatic control board was developed for generating cyclic patterns of grasping and locomotion. Different reinforcing patterns and materials characterize the locomotor actuators’ dynamical responses to the varying input pressures. The robot was tested in a laboratory setting to navigate a cable, and the collected data were used to modify the designs and control software and hardware. The capability of the soft robot for navigating cables in vertical, horizontal, and curved path scenarios was successfully demonstrated. Compared to the initial design, the forward speed is improved three-fold.

Correlation Between Skin Galvanic Response with Snake Photographs, Self-Assessment of Fear, and the Level of Natural Snake Fear

Correlation Between Skin Galvanic Response with Snake Photographs, Self-Assessment of Fear, and the Level of Natural Snake Fear

The population genetics of the causative agent of snake fungal disease indicate recent introductions to the USA.

Snake fungal disease (SFD; ophidiomycosis), caused by the pathogen Ophidiomyces ophiodiicola (Oo), has been documented in wild snakes in North America and Eurasia, and is considered an emerging disease in the eastern United States of America. However, a lack of historical disease data has made it challenging to determine whether Oo is a recent arrival to the USA or whether SFD emergence is due to other factors. Here, we examined the genomes of 82 Oo strains to determine the pathogen's history in the eastern USA. Oo strains from the USA formed a clade (Clade II) distinct from European strains (Clade I), and molecular dating indicated that these clades diverged too recently (approximately 2,000 years ago) for transcontinental dispersal of Oo to have occurred via natural snake movements across Beringia. A lack of nonrecombinant intermediates between clonal lineages in Clade II indicates that Oo has actually been introduced multiple times to North America from an unsampled source population, and molecular dating indicates that several of these introductions occurred within the last few hundred years. Molecular dating also indicated that the most common Clade II clonal lineages have expanded recently in the USA, with time of most recent common ancestor mean estimates ranging from 1985 to 2007 CE. The presence of Clade II in captive snakes worldwide demonstrates a potential mechanism of introduction and highlights that additional incursions are likely unless action is taken to reduce the risk of pathogen translocation and spillover into wild snake populations.

Snake Robots for Rescue Operation

The motivation for snake robots originates from natural snakes. Snakes show better versatility abilities and can move over basically any kind of landscape, including limited and restricted spaces. Like a snake, robot has an exceptionally expressed robot controller arm with the capacity of giving its own drive. Wheel-less, limbless secluded Snake-like robot (Snake robot) has superior capacities in flexibility and adoptability to nature in examination with the most haggled vehicles. Some helpful highlights of snake-like robots incorporate smaller size of the cross-sectional regions, steadiness, capacity to work in troublesome landscape, great footing, high redundancy and complete fixing of the inside systems. Our model consists of multiple links joined together to create propulsion on its own in a spatial environment. The first link (head) can have various configurations like camera, gripper, etc. This makes the snake robot ideal for search and rescue operation.

Energy-efficient and damage-recovery slithering gait design for a snake-like robot based on reinforcement learning and inverse reinforcement learning

Similar to real snakes in nature, the flexible trunks of snake-like robots enhance their movement capabilities and adaptabilities in diverse environments. However, this flexibility corresponds to a complex control task involving highly redundant degrees of freedom, where traditional model-based methods usually fail to propel the robots energy-efficiently and adaptively to unforeseeable joint damage. In this work, we present an approach for designing an energy-efficient and damage-recovery slithering gait for a snake-like robot using the reinforcement learning (RL) algorithm and the inverse reinforcement learning (IRL) algorithm. Specifically, we first present an RL-based controller for generating locomotion gaits at a wide range of velocities, which is trained using the proximal policy optimization (PPO) algorithm. Then, by taking the RL-based controller as an expert and collecting trajectories from it, we train an IRL-based controller using the adversarial inverse reinforcement learning (AIRL) algorithm. For the purpose of comparison, a traditional parameterized gait controller is presented as the baseline and the parameter sets are optimized using the grid search and Bayesian optimization algorithm. Based on the analysis of the simulation results, we first demonstrate that this RL-based controller exhibits very natural and adaptive movements, which are also substantially more energy-efficient than the gaits generated by the parameterized controller. We then demonstrate that the IRL-based controller cannot only exhibit similar performances as the RL-based controller, but can also recover from the unpredictable damage body joints and still outperform the model-based controller, which has an undamaged body, in terms of energy efficiency. Videos can be viewed at https://videoviewsite.wixsite.com/rlsnake.

The interaction between the natural metalloendopeptidase inhibitor BJ46a and its target toxin jararhagin analyzed by structural mass spectrometry and molecular modeling

Snakebite envenoming affects millions of people worldwide, being officially considered a neglected tropical disease by the World Health Organization. The antivenom is effective in neutralizing the systemic effects of envenomation, but local effects are poorly neutralized, often leading to permanent disability. The natural resistance of the South American pit viper Bothrops jararaca to its venom is partly attributed to BJ46a, a natural snake venom metalloendopeptidase inhibitor. Upon complex formation, BJ46a binds non-covalently to the metalloendopeptidase, rendering it unable to exert its proteolytic activity. However, the structural features that govern this interaction are largely unknown. In this work, we applied structural mass spectrometry techniques (cross-linking-MS and hydrogen-deuterium exchange MS) and in silico analyses (molecular modeling, docking, and dynamics simulations) to understand the interaction between BJ46a and jararhagin, a metalloendopeptidase from B. jararaca venom. We explored the distance restraints generated from XL-MS experiments to guide the modeling of BJ46a and jararhagin, as well as the protein-protein docking simulations. HDX-MS data pinpointed regions of protection/deprotection at the interface of the BJ46a–jararhagin complex which, in addition to the molecular dynamics simulation data, reinforced our proposed interaction model. Ultimately, the structural understanding of snake venom metalloendopeptidases inhibition by BJ46a could lead to the rational design of drugs to improve anti-snake venom therapeutics, alleviating the high morbidity rates currently observed.

Snake Venom Cathelicidins as Natural Antimicrobial Peptides.

Bioactive small molecules isolated from animals, plants, fungi and bacteria, including natural antimicrobial peptides, have shown great therapeutic potential worldwide. Among these peptides, snake venom cathelicidins are being widely exploited, because the variation in the composition of the venom reflects a range of biological activities that may be of biotechnological interest. Cathelicidins are short, cationic, and amphipathic molecules. They play an important role in host defense against microbial infections. We are currently facing a strong limitation on pharmacological interventions for infection control, which has become increasingly complex due to the lack of effective therapeutic options. In this review, we will focus on natural snake venom cathelicidins as promising candidates for the development of new antibacterial agents to fight antibiotic-resistant bacteria. We will highlight their antibacterial and antibiofilm activities, mechanism of action, and modulation of the innate immune response.

Structural analysis of the natural snake venom metalloendopeptidase inhibitor BJ46a and its target toxin, jararhagin, based on XL-MS and HDX-MS

Structural analysis of the natural snake venom metalloendopeptidase inhibitor BJ46a and its target toxin, jararhagin, based on XL-MS and HDX-MS

Natural Snake Venom Inhibitors and their Pharmaceutical Uses: Challenges and Possibilities.

Nowadays, treatment with specific antivenins is considered the only cure for snakebites accidents. However, access to antivenom obstructs the successful implementation of the World Health Organization international guidelines. In the last few years, natural organic compounds, peptides, and proteins with the ability to inhibit snake toxins and obtained from different sources such as plant extracts and animal blood have been proposed as antivenoms. In this work, we will focus on the inhibitors of the main venom toxins, phospholipases A2 and metalloproteinases, and their application as novel antivenoms.

Pharmacological characterization of crotamine effects on mice hind limb paralysis employing both ex vivo and in vivo assays: Insights into the involvement of voltage-gated ion channels in the crotamine action on skeletal muscles.

The high medical importance of Crotalus snakes is unquestionable, as this genus is the second in frequency of ophidian accidents in many countries, including Brazil. With a relative less complex composition compared to other genera venoms, as those from the Bothrops genus, the Crotalus genus venom from South America is composed basically by the neurotoxin crotoxin (a phospholipase A2), the thrombin-like gyroxin (a serinoprotease), a very potent aggregating protein convulxin, and a myotoxic polypeptide named crotamine. Interestingly not all Crotalus snakes express crotamine, which was first described in early 50s due to its ability to immobilize animal hind limbs, contributing therefore to the physical immobilization of preys and representing an important advantage for the envenoming efficacy, and consequently, for the feeding and survival of these snakes in nature. Representing about 10–25% of the dry weight of the crude venom of crotamine-positive rattlesnakes, the polypeptide crotamine is also suggested to be of importance for antivenom therapy, although the contribution of this toxin to the main symptoms of envenoming process remains far unknown until now. Herein, we concomitantly performed in vitro and in vivo assays to show for the first time the dose-dependent response of crotamine-triggered hind limbs paralysis syndrome, up to now believed to be observable only at high (sub-lethal) concentrations of crotamine. In addition, ex vivo assay performed with isolated skeletal muscles allowed us to suggest here that compounds active on voltage-sensitive sodium and/or potassium ion channels could both affect the positive inotropic effect elicited by crotamine in isolated diaphragm, besides also affecting the hind limbs paralysis syndrome imposed by crotamine in vivo. By identifying the potential molecular targets of this toxin, our data may contribute to open new roads for translational studies aiming to improve the snakebite envenoming treatment in human. Interestingly, we also demonstrate that the intraplantal or intraperitoneal (ip) injections of crotamine in mice do not promote pain. Therefore, this work may also suggest the profitable utility of non-toxic analogs of crotamine as a potential tool for targeting voltage-gated ion channels in skeletal muscles, aiming its potential use in the therapy of neuromuscular dysfunctions and envenoming therapy.

Motion Investigation of a Snake Robot with Different Scale Geometry and Coefficient of Friction

Most snakes in nature have scales at their ventral sides. The anisotropic frictional coefficient of the ventral side of the snakes, as well as snake robots, is considered to be responsible for their serpentine kind of locomotion. However, little work has been done on snake scales so far to make any guidelines for designing snake robots. This paper presents an experimental investigation on the effects of artificial scale geometry on the motion of snake robots that move in a serpentine manner. The motion of a snake robot equipped with artificial scales with different geometries was recorded using a Kinect camera under different speeds of the actuating motors attached to the links of the robot. The results of the investigation showed that the portion of the scales along the central line of the robot did not contributed to the locomotion of the robot, rather, it is the parts of the scales along the lateral edges of the robot that contributed to the motion. It was also found that the lower frictional ratio at low slithering speeds made the snake robot motion unpredictable. The scales with ridges along the direction of the snake body gave better and more stable motion. However, to get the peg effect, the scales needed to have a very high lateral to forward friction ratio, otherwise, significant side slipping occurred, resulting in unpredictable motion.

Predation on artificial and natural nests in the lowland rainforest of Papua New Guinea

ABSTRACTCapsule: Although survival of nests was similar between forest fragments and continuous forest, the range of predators differed. Artificial nests provide an under-estimate of nest predation by snakes.Aims: To estimate the natural nest predation rate in continuous primary forest, compare it with predation rates in forest fragments. To assess the reliability of nest survival rates determined by the use of artificial nests with clay eggs and identify the main nest predators.Methods: We observed survival of natural nests during the incubation period in continuous primary forest in Papua New Guinea. Some nests were monitored with infrared cameras. We also used artificial nests deployed with clay eggs to identify predators.Results: There was a predation rate of 50% for natural nests and snakes were major predators of nest contents. Clutch daily survival rates (DSRs) differed among nest types. The DSR of artificial nests (0.977) was not significantly different to that of natural cup nests (0.969). Survival rates of artificial nests were similar in forest fragments and continuous forest. Forest fragments had, however, a higher proportion of avian predators than continuous forest.Conclusion: Although, we observed similar survival rates in artificial and natural nests, the composition of nest predators was different between natural and artificial nests. Artificial nests were not suitable for estimating the real predation caused by reptiles. Nevertheless, we find that participation of avian nest predators can be estimated correctly with the use of artificial nests.

Study of the mechanical performance and analysis of hybrid natural snake grass-jute-glass fiber strengthened polyester composite

The research paper involves fiber composites form a special category materials that are contributing to present swaping of manufactured hybrid which finds traditional and non traditional applications. The study explains which are accentuates and optimizing for the recently recognized snake grass standard materials. In this article, the prospecting performance characterization of SG fiber is selected and contrasted as per the ASTM standard. This study additionally manages the examination apply different phenomena of this stages in Jute and snake as fortifications utilized index ended a try. Experiments have been conducted on normal Filaments, snake grass, Glass Fiber and Jute to analyse their Mechanical properties. The common strands are orchestrated in the flat and vertical heading as transferred quality on all sides. Microstructural analysis of these hybrid composite is observed using Scanning Electron Microscope that reveals bonding and Filament breaksge, Voids and Fiber decover which are further investigated.

Disintegrins from the Venom of Vipera ammodytes ammodytes Efficiently Inhibit Migration of Breast Cancer Cells.

Integrins are plasma membrane proteins, whose dysfunction frequently results in cancer pathology, and therefore they represent important targets of anti-tumour therapy. Snake venoms are a rich source of disintegrins (Dis), proteins that specifically bind integrins and thus interfere with their functions. In an attempt to discover new molecules for treatment of breast cancer, the major type of cancer in women, we isolated a dimeric Dis (Vaa-Dis) from the venom of the nosehorned viper. By cell viability testing we demonstrated that 50 nM and higher concentrations of Vaa-Dis were toxic to highly invasive human breast adenocarcinoma cell line MDA-MB-231. Wound-healing assay revealed that already at one order of magnitude lower concentrations Vaa-Dis efficiently inhibited MDA-MB-231 cell migration. This exposed a promising anti-metastatic potential of Vaa-Dis and a good perspective of these natural snake venom proteins for further research and development towards the application in breast cancer treatment.

MODEL PEMBELAJARAN IPA DENGAN ALAT PERAGA SEDERHANA UNTUK MENINGKATKAN PEMAHAMAN DAN KREATIVITAS SISWA DI MTS MA’ARIF CIKERUH, JATINANGOR

ABSTRACTPracticum is a teaching strategy that is used to describe the learning materials. Props is one of the practical tools needed to assist in the learning activities. The purpose of this activity is to create props in enhancing the understanding and creativity of students in science subjects in MTs Ma’arif Cikeruh, Jatinangor. The event begins socialization to MTs Ma’arif Cikeruh Jatinangor, followed by the preparation of tools and materials to be used, then conducted the experiment installation of equipment before it is demonstrated to the students. Before making props, students are given a pre-test and explanation of theories related to props are made. Props are made include simple auksanometer, simple bioreactor, simple distillation apparatus, means of fermentation, miniature hydraulic pump, a water filter is simple, natural ph indicator, colored fountains, and sugar snake. Implementation of the activities take place every two weeks for four months from March to June 2016 and will be associated with the ongoing evaluation and monitoring activities. Evaluation and monitoring includes affective, psychomotor, and cognitive. Rate affective and psychomotor aspects conveniently indicates the criteria very well, while the students do with the cognitive aspects of the pre-test and post-test each meeting. The average value of the pre-test is 40.75, after a practicum conducted post-test with the average value is 74.125. Thus concluded practicum enhance students' understanding of 33.375.Keywords: simple props, science, junior high school students

Natural Inhibitors of Snake Venom Metalloendopeptidases: History and Current Challenges.

The research on natural snake venom metalloendopeptidase inhibitors (SVMPIs) began in the 18th century with the pioneering work of Fontana on the resistance that vipers exhibited to their own venom. During the past 40 years, SVMPIs have been isolated mainly from the sera of resistant animals, and characterized to different extents. They are acidic oligomeric glycoproteins that remain biologically active over a wide range of pH and temperature values. Based on primary structure determination, mammalian plasmatic SVMPIs are classified as members of the immunoglobulin (Ig) supergene protein family, while the one isolated from muscle belongs to the ficolin/opsonin P35 family. On the other hand, SVMPIs from snake plasma have been placed in the cystatin superfamily. These natural antitoxins constitute the first line of defense against snake venoms, inhibiting the catalytic activities of snake venom metalloendopeptidases through the establishment of high-affinity, non-covalent interactions. This review presents a historical account of the field of natural resistance, summarizing its main discoveries and current challenges, which are mostly related to the limitations that preclude three-dimensional structural determinations of these inhibitors using “gold-standard” methods; perspectives on how to circumvent such limitations are presented. Potential applications of these SVMPIs in medicine are also highlighted.

Orthogonal optimization of prokaryotic expression of a natural snake venom phospholipase A2 inhibitor from Sinonatrix annularis

Phospholipase A2 (PLA2) is a calcium-dependent enzyme that is involved in inflammatory processes such as the liberation of free arachidonic acid from the membrane pool for the biosynthesis of eicosanoids. Snake venom are known containing PLA2s (svPLA2s) which exhibit a wide variety of pharmacological effects including neurotoxicity, cardiotoxicity, myotoxicity and hemorrhage. Therefore, inhibition of svPLA2 would be advantageous to successful envenomation treatment. A gamma type PLI (PLA2 inhibitor) has been extracted from the serum of Sinonatrix annularis, a non-venomous snake indigenous to China. This showed strong inhibition of Deinagkistrrodon acutus PLA2, however, the PLIγ level in the serum and snake resource are not sufficiently sustainable for further research. To overcome these limitations, we constructed a His6-PLIγ pET28 fusion expression vector and transformed Escherichia coli BL21. To improve the expression of PLIγ, an orthogonal experiment [L16(4)5] was performed to optimize induction parameters. The optimized condition was determined to be: induction by 0.4 mM isopropyl-β-d-thiogalactoside (IPTG) for 6 h to the recombinant BL21 after its OD600 was 0.8, with continuous shaking cultivation at 190 rpm and 35 °C. Under these conditions, the amount of expressed protein could reach 57 mg/L. The His6-PLIγ was purified by nickel affinity chromatography and renatured by On-column refolding. The resulting PLIγ showed a good inhibitory effect of enzymatic activities to venom PLA2 isolated from D. acutus. Moreover, the PLIγ had a wide anti-hemorrhage activities to D. acutus, Naja atra and Agkistrodon halys venom.

Exotic snake bites in the Czech Republic—Epidemiological and clinical aspects during 15-year period (1999–2013)

Only one natural venomous snake—the adder viper—lives in the central European region and its bite is usually associated only with mild course of envenoming. Cases of envenoming caused by exotic snakes among their breeders are clinically more important. Objective. The aim of this study was to analyze the epidemiological and clinical aspects of registered venomous bites caused by exotic snakes in the Czech Republic over a period of 15 years (1999–2013). Materials and methods. This is an observational case series. Data have been collected retrospectively from a database and medical charts of the Toxinology Center belonging to the General University Hospital in Prague. Results. In total, 87 cases of exotic snakebites caused by 34 venomous snake species were registered during the study period, coming from 18 genera of Elapinae, Viperinae, and Crotalinae subfamilies. In the cohort, 29 patients (33.3%) developed systemic envenoming and 17 (19.5%) were treated with antivenom. Ten cases of envenoming (11.5%) were considered as potentially life threatening. No patient died due to envenoming caused by exotic snake bites during the study period. Four illustrative cases of envenoming (Echis pyramidum, Dendroaspis polylepis, Protobothrops mangshanensis, and Proatheris superciliaris) are described in detail. Conclusion. Bites caused by exotic snakes resulted in serious and life-threatening envenomings in some patients. Early transfer to the Center, antivenom administration, and support of failing organ functions contributed to favorable outcome of victims.

Design and Modeling of a New Drive System and Exaggerated Rectilinear-Gait for a Snake-Inspired Robot

In recent years, snake-inspired locomotion has garnered increasing interest in the bio-inspired robotics community. This positive trend is largely due to the unique and highly effective gaits utilized by snakes to traverse various terrains and obstacles. These gaits make use of a snake's hyper-redundant body structure to adapt to the terrain and maneuver through tight spaces. Snake-inspired robots utilizing rectilinear motion, one of the primary gaits observed in natural snakes, have demonstrated favorable results on various terrains. However, previous robot designs utilizing rectilinear gaits were slow in speed. This paper presents a design and an exaggerated rectilinear gait concept for a snake-inspired robot which overcomes this limitation. The robot concept incorporates high speed linear motion and a new multimaterial, variable friction force anchoring concept. A series of traction experiments are conducted to determine appropriate materials to be used in the friction anchor (FA) design. The gait concept includes four unique gaits: a forward and a turning gait, which both emphasize speed for the robot; and a forward and turning gait which emphasize traction. We also report a comparative study of the performance of prototype robot designed using these concepts to other published snake-inspired robot designs.

3A1-X10 ヘビ型ロボットによる等方的摩擦条件における蛇行推進(バイオミメティクス・バイオメカトロニクス)

For snake-like robots, lateral undulatory locomotion has been realized by attaching passive wheels that prevent sideway slip. Utilization of anisotropic friction has been confirmed by biological experiments and considered to be an important factor of lateral undulation. Meanwhile, snakes in nature do not always rely on the anisotropy. In fact, on a smooth and flat surface, they change the weight distribution and concentrate contact force on specific parts of the body, which is known as sinus lifting. This paper shows that lateral undulation can be achieved even with isotropic friction by increasing weight on the point where the magnitude of curvature derivative becomes large.