| denim clothing reduces venom expenditure by rattlesnakes striking defensively at model human limbs. | venomous snakebites can be painful, costly, and potentially life threatening. we seek to learn whether ordinary clothing (denim material from blue jeans) interferes with the kinematics of venom delivery, thereby reducing the amount of venom injected by a representative viper into a human limb. | 2009 | 19942067 |
| california ground squirrel (spermophilus beecheyi) defenses against rattlesnake venom digestive and hemostatic toxins. | previous studies have shown that some mammals are able to neutralize venom from snake predators. california ground squirrels (spermophilus beecheyi) show variation among populations in their ability to bind venom and minimize damage from northern pacific rattlesnakes (crotalus oreganus), but the venom toxins targeted by resistance have not been investigated. four california ground squirrel populations, selected for differences in local density or type of rattlesnake predators, were assayed for t ... | 2005 | 16273425 |
| isolation and identification of a snake venom metalloproteinase inhibitor from california ground squirrel (spermophilus beecheyi) blood sera. | california ground squirrels (spermophilus beecheyi) show blood-based defenses to a variety of toxins in the venom of the northern pacific rattlesnake (crotalus oreganus oreganus). in this study we demonstrate the presence of an effective snake venom metalloproteinase inhibitor (svmpi) in s. beecheyi. the blood sera of california ground squirrels were effective at reducing the metalloproteinase activity of northern pacific (c. o. oreganus) and prairie rattlesnake (crotalus viridis viridis) venoms ... | 2011 | 21903126 |
| a novel phospholipase a2 (d49) from the venom of the crotalus oreganus abyssus (north american grand canyon rattlesnake). | currently, crotalus viridis was divided into two species: crotalus viridis and crotalus oreganus. the current classification divides "the old" crotalus viridis into two new and independent species: crotalus viridis (subspecies: viridis and nuntius) and crotalus oreganus (subspecies: abyssus, lutosus, concolor, oreganus, helleri, cerberus, and caliginis). the analysis of a product from cdna (e6d), derived from the gland of a specie crotalus viridis viridis, was found to produce an acid phospholip ... | 2014 | 24707493 |
| comparison of the protective effect of a commercially available western diamondback rattlesnake toxoid vaccine for dogs against envenomation of mice with western diamondback rattlesnake (crotalus atrox), northern pacific rattlesnake (crotalus oreganus oreganus), and southern pacific rattlesnake (crotalus oreganus helleri) venom. | to evaluate effectiveness of a commercially available toxoid manufactured from western diamondback (wd) rattlesnake (crotalus atrox) venom against envenomation of mice with wd, northern pacific (np) rattlesnake (crotalus oreganus oreganus), and southern pacific (sp) rattlesnake (crotalus oreganus helleri) venom. | 2015 | 25710764 |
| biochemical and functional studies of coltx-i, a new myotoxic phospholipase a2 isolated from crotalus oreganus lutosus (great basin rattlesnake) snake venom. | commonly, phospholipases a2 (pla2s) play key roles in the pathogenesis of the local tissue damage characteristic of crotaline and viperine snake envenomations. crotalus oreganus lutosus snake venom has not been extensively studied; therefore, the characterization of its components represents a valuable biotechnological tool for studying pathophysiological processes of envenoming and for gaining a deeper understanding of its biological effects. in this study, for the first time, a basic pla2 myot ... | 2016 | 26996495 |
| intraspecific venom variation in the medically significant southern pacific rattlesnake (crotalus oreganus helleri): biodiscovery, clinical and evolutionary implications. | due to the extreme variation of venom, which consequently results in drastically variable degrees of neutralization by crofab antivenom, the management and treatment of envenoming by crotalus oreganus helleri (the southern pacific rattlesnake), one of the most medically significant snake species in all of north america, has been a clinician's nightmare. this snake has also been the subject of sensational news stories regarding supposed rapid (within the last few decades) evolution of its venom. ... | 2014 | 24463169 |
| snake venomics of crotalus tigris: the minimalist toxin arsenal of the deadliest neartic rattlesnake venom. evolutionary clues for generating a pan-specific antivenom against crotalid type ii venoms. | we report the proteomic and antivenomic characterization of crotalus tigris venom. this venom exhibits the highest lethality for mice among rattlesnakes and the simplest toxin proteome reported to date. the venom proteome of c. tigris comprises 7-8 gene products from 6 toxin families; the presynaptic β-neurotoxic heterodimeric pla(2), mojave toxin, and two serine proteinases comprise, respectively, 66 and 27% of the c. tigris toxin arsenal, whereas a vegf-like protein, a crisp molecule, a medi ... | 2011 | 22181673 |
| rock squirrel (spermophilus variegatus) blood sera affects proteolytic and hemolytic activities of rattlesnake venoms. | rock squirrels (spermophilus variegatus) from two sites in south central new mexico, where prairie (crotalus viridis viridis) and western diamondback (crotalus atrox) rattlesnakes are common predators, were assayed for inhibition of rattlesnake venom digestive and hemostatic activities. at statistically significant levels rock squirrel blood sera reduced the metalloprotease and hemolytic activity of venoms from c. v. viridis and c. atrox more than venom from an allopatric snake species, the nort ... | 2010 | 21184770 |
| ground squirrels use an infrared signal to deter rattlesnake predation. | the evolution of communicative signals involves a major hurdle; signals need to effectively stimulate the sensory systems of their targets. therefore, sensory specializations of target animals are important sources of selection on signal structure. here we report the discovery of an animal signal that uses a previously unknown communicative modality, infrared radiation or "radiant heat," which capitalizes on the infrared sensory capabilities of the signal's target. california ground squirrels (s ... | 2007 | 17704254 |
| california ground squirrel (spermophilus beecheyi) defenses against rattlesnake venom digestive and hemostatic toxins. | previous studies have shown that some mammals are able to neutralize venom from snake predators. california ground squirrels (spermophilus beecheyi) show variation among populations in their ability to bind venom and minimize damage from northern pacific rattlesnakes (crotalus oreganus), but the venom toxins targeted by resistance have not been investigated. four california ground squirrel populations, selected for differences in local density or type of rattlesnake predators, were assayed for t ... | 2006 | 16525875 |
| quantitative analysis of snake venoms using soluble polymer-based isotope labeling. | we present the design and synthesis of a new quantitative strategy termed soluble polymer-based isotope labeling (sopil) and its application as a novel and inclusive method for the identification and relative quantification of individual proteins in complex snake venoms. the sopil reagent selectively captures and isolates cysteine-containing peptides, and the subsequent tagged peptides are released and analyzed using nanoflow liquid chromatography-tandem mass spectrometry. the sopil strategy was ... | 2008 | 18089550 |
| the effects of hybridization on divergent venom phenotypes: characterization of venom from crotalus scutulatus scutulatus × crotalus oreganus helleri hybrids. | hybridization between divergent species can be analyzed to elucidate expression patterns of distinct parental characteristics, as well as to provide information about the extent of reproductive isolation between species. a known hybrid cross between two rattlesnakes with highly divergent venom phenotypes provided the opportunity to examine occurrence of parental venom characteristics in the f1 hybrids as well as ontogenetic shifts in the expression of these characters as the hybrids aged. althou ... | 2016 | 27496060 |
| coatx-ii, a new dimeric lys49 phospholipase a2 from crotalus oreganus abyssus snake venom with bactericidal potential: insights into its structure and biological roles. | snake venoms are rich and intriguing sources of biologically-active molecules that act on target cells, modulating a diversity of physiological functions and presenting promising pharmacological applications. lys49 phospholipase a2 is one of the multifunctional proteins present in these complex secretions and, although catalytically inactive, has a variety of biological activities, including cytotoxic, antibacterial, inflammatory, antifungal activities. herein, a lys49 phospholipase a2, denomina ... | 2016 | 27530662 |
| presence of peptide inhibitors in rattlesnake venoms and their effects on endogenous metalloproteases. | long-term storage of proteins with retention of biological activity is a concern for many actual and potential protein drugs. a model for stabilization of proteins for long periods could exist in natural systems, particularly among viperid snakes whose venoms are rich in lytic enzymes, because when secreted into the lumen, they are stored in an inactive and competent state for many months. one mechanism inhibiting autolysis is the production of (relatively) low affinity peptide enzyme inhibitors ... | 2005 | 15683863 |
| complement inactivating proteins and intraspecies venom variation in crotalus oreganus helleri. | complement inactivating properties were detected in venom from the southern california distribution of crotalus oreganus helleri (southern pacific rattlesnake). this activity showed strong geographic bias to the san bernardino mountain range, and venom from this area reacted strongly with fraction 5 antiserum (af5). however, venoms from the san jacinto mountain range, which have been previously shown to contain mojave toxin, did not inhibit complement and did not react with af5. af5 has been pre ... | 2007 | 17134729 |
| syncope, massive aspiration, and sudden death following rattlesnake bite. | fatalities following rattlesnake bite are rare in the united states, usually occur some hours following the bite, and are generally secondary to direct venom effects. we report a patient with acute syncope and subsequent massive aspiration resulting in airway obstruction and rapid death following a probable northern pacific rattlesnake (crotalus oreganus oreganus) bite. | 2007 | 17896845 |
| the forked tongue and edge detection in snakes (crotalus oreganus): an experimental test. | many stimulus-detection systems are lateralized to allow for simultaneous comparison of paired stimuli. it has been hypothesized that the deeply forked tongue of snakes and some derived lizards functions as a chemical edge detector where cues gathered by each tine are kept separate to provide two points of lateral odor assessment by the central nervous system via vomeronasal input. while following a chemical trail, one time can be on the trail, the other off, and such differential information pr ... | 2008 | 18298279 |
| venom variation in hemostasis of the southern pacific rattlesnake (crotalus oreganus helleri): isolation of hellerase. | envenomations by the southern pacific rattlesnake (crotalus oreganus helleri) are the most common snakebite accidents in southern california. intraspecies venom variation may lead to unresponsiveness to antivenom therapy. even in a known species, venom toxins are recognized as diverse in conformity with interpopulational, seasonal, ontogenetic and individual factors. five venoms of individual c. oreganus helleri located in riverside and san bernardino counties of southern california were studied ... | 2009 | 18804187 |
| the relationship between plasma steroid hormone concentrations and the reproductive cycle in the northern pacific rattlesnake, crotalus oreganus. | we describe the reproductive cycle of northern pacific rattlesnakes (crotalus oreganus) by quantifying steroid hormone concentrations and observing reproductive behaviors in free-ranging individuals. additionally, we examined reproductive tissues from museum specimens. plasma steroid hormone concentrations were quantified for both male and female snakes throughout the active season (march-october). we measured testosterone (t), 5alpha-dihydrotestosterone (dht), and corticosterone (b) concentrati ... | 2010 | 20138180 |
| evolutionary trends in venom composition in the western rattlesnakes (crotalus viridis sensu lato): toxicity vs. tenderizers. | the western rattlesnake (crotalus viridis sensu lato, now including crotalus oreganus) is broadly distributed across the western half of the united states, northwestern mexico and southwestern canada, and eight subspecies are currently recognized. although some venom characteristics have been noted for most subspecies, a systematic study of venoms from all subspecies has not been reported. venom was extracted from snakes collected from approximate geographic range centers for all subspecies and ... | 2010 | 20227433 |
| comparative study of anticoagulant and procoagulant properties of 28 snake venoms from families elapidae, viperidae, and purified russell's viper venom-factor x activator (rvv-x). | snake venoms consist of numerous molecules with diverse biological functions used for capturing prey. each component of venom has a specific target, and alters the biological function of its target. once these molecules are identified, characterized, and cloned; they could have medical applications. the activated clotting time (act) and clot rate were used for screening procoagulant and anticoagulant properties of 28 snake venoms. crude venoms from daboia russellii siamensis, bothrops asper, bot ... | 2010 | 20677373 |
| vascular effects and electrolyte homeostasis of the natriuretic peptide isolated from crotalus oreganus abyssus (north american grand canyon rattlesnake) venom. | crotalus oreganus abyssus is a rattlesnake that is usually found in the grand canyon, united states of america. knowledge regarding the composition of c. o. abyssus venom is scarce. new natriuretic peptides (nps) have been isolated and characterized from the venoms of members of the crotalinae family. the np family comprises three members, anp (atrial natriuretic peptide), bnp (b-type natriuretic peptide) and cnp (c-type natriuretic peptide), and has an important role in blood pressure regulatio ... | 2012 | 22617223 |
| evaluating the thermal effects of translocation in a large-bodied pitviper. | acute stressors can be costly, often requiring alteration of normal physiological processes to mitigate their effects. animal translocation may be a very stressful event and result in a reduced ability to maintain homeostasis. the impacts of translocation on the thermal ecology of ectothermic vertebrates, which may rely on preferred habitats for thermoregulation, are currently unknown. in this study, 22 adult male northern pacific rattlesnakes (crotalus oreganus oreganus) were implanted with aut ... | 2014 | 24962181 |
| behavioral thermal tolerances of free-ranging rattlesnakes (crotalus oreganus) during the summer foraging season. | increasing temperature due to climate change is one of the greatest challenges for wildlife worldwide. behavioral data on free-ranging individuals is necessary to determine at what temperatures animals modify activity as this would determine their capacity to continue to move, forage, and mate under altered thermal regimes. in particular, high temperatures could limit available surface activity time and time spent on fitness-related activities. conversely, performance, such as feeding rate, can ... | 2017 | 28343580 |
| good vibrations: assessing the stability of snake venom composition after researcher-induced disturbance in the laboratory. | phenotypic plasticity contributes to intraspecific variation in traits of many animal species. venom is an integral trait to the success and survival of many snake species, and potential plasticity in venom composition is important to account for in the context of basic research as well as in human medicine for treating the various symptoms of snakebite and producing effective anti-venoms. researchers may unknowingly induce changes in venom variation by subjecting snakes to novel disturbances an ... | 2017 | 28487160 |
| biological activities of a new crotamine-like peptide from crotalus oreganus helleri on c2c12 and cho cell lines, and ultrastructural changes on motor endplate and striated muscle. | crotamine and crotamine-like peptides are non-enzymatic polypeptides, belonging to the family of myotoxins, which are found in high concentration in the venom of the crotalus genus. helleramine was isolated and purified from the venom of the southern pacific rattlesnake, crotalus oreganus helleri. this peptide had a similar, but unique, identity to crotamine and crotamine-like proteins isolated from other rattlesnakes species. the variability of crotamine-like protein amino acid sequences may al ... | 2020 | 33065200 |
| local prey community composition and genetic distance predict venom divergence among populations of the northern pacific rattlesnake (crotalus oreganus). | identifying the environmental correlates of divergence in functional traits between populations can provide insights into the evolutionary mechanisms that generate local adaptation. here, we assess patterns of population differentiation in expressed venom proteins in northern pacific rattlesnakes (crotalus oreganus) from 13 locations across california. we evaluate the relative importance of major biotic (prey species community composition), abiotic (temperature, precipitation and elevation) and ... | 2018 | 29959877 |
| obtaining plasma to measure baseline corticosterone concentrations in reptiles: how quick is quick enough? | there is growing interest in the use of glucocorticoid (gc) hormones to understand how wild animals respond to environmental challenges. blood is the best medium for obtaining information about recent gc levels; however, obtaining blood requires restraint and can therefore be stressful and affect gc levels. there is a delay in gcs entering blood, and it is assumed that blood obtained within 3 min of first disturbing an animal reflects a baseline level of gcs, based largely on studies of birds an ... | 2020 | 31733208 |
| the effects of temperature on the defensive strikes of rattlesnakes. | movements of ectotherms are constrained by their body temperature owing to the effects of temperature on muscle physiology. as physical performance often affects the outcome of predator-prey interactions, environmental temperature can influence the ability of ectotherms to capture prey and/or defend themselves against predators. however, previous research on the kinematics of ectotherms suggests that some species may use elastic storage mechanisms when attacking or defending, thereby mitigating ... | 2020 | 32561628 |
| genotyping-in-thousands by sequencing reveals marked population structure in western rattlesnakes to inform conservation status. | delineation of units below the species level is critical for prioritizing conservation actions for species at-risk. genetic studies play an important role in characterizing patterns of population connectivity and diversity to inform the designation of conservation units, especially for populations that are geographically isolated. the northernmost range margin of western rattlesnakes (crotalus oreganus) occurs in british columbia, canada, where it is federally classified as threatened and restri ... | 2020 | 32760519 |
| rattlesnake migrations and the implications of thermal landscapes. | the importance of thermal resources to terrestrial ectotherms has been well documented but less often considered in larger-scale analyses of habitat use and selection, such as those routinely conducted using standard habitat features such as vegetation and physical structure. selection of habitat based on thermal attributes may be of particular importance for ectothermic species, especially in colder climates. in canada, western rattlesnakes (crotalus oreganus) reach their northern limits, with ... | 2020 | 32514356 |
| a novel synthetic peptide inspired on lys49 phospholipase a2 from crotalus oreganus abyssus snake venom active against multidrug-resistant clinical isolates. | currently, the evolving and complex mechanisms of bacterial resistance to conventional antibiotics are increasing, while alternative medicines are drying up, which urges the need to discover novel agents able to kill antibiotic-resistant bacteria. lys49 phospholipase a2s (pla2s) from snake venoms are multifunctional toxins able to induce a huge variety of therapeutic effects and consequently serve as templates for new drug leads. hence, the present study was aimed at the synthesis of oligopeptid ... | 2018 | 29501945 |
| crotamine-like from southern pacific rattlesnake (crotalus oreganus helleri) venom acts on human leukemia (k-562) cell lines and produces ultrastructural changes on mice adrenal gland. | crotamine is a cationic, non-enzymatic, protein integrating a minor family of myotoxins, composed of 42 amino acid residues, described in viperidae and crotalidae snake's families that has been used in neuroscience research, drug progressing and molecular diversity reports. crotamine-like protein (clp) from c.o.helleri venom was isolated in fraction 5 from 7 peaks obtained by sulfopropyl waters protein pak cationic exchange column. in tricine-sds-page under non-reduced conditions this clp showed ... | 2020 | 29466088 |
| genotyping-in-thousands by sequencing (gt-seq) panel development and application to minimally invasive dna samples to support studies in molecular ecology. | minimally invasive sampling (mis) is widespread in wildlife studies; however, its utility for massively parallel dna sequencing (mps) is limited. poor sample quality and contamination by exogenous dna can make mis challenging to use with modern genotyping-by-sequencing approaches, which have been traditionally developed for high-quality dna sources. given that mis is often more appropriate in many contexts, there is a need to make such samples practical for harnessing mps. here, we test the abil ... | 2020 | 31483931 |
| one bite, two patients: disparate clinical courses following simultaneous crotalus oreganus abyssus envenomation. | a number of crotaline species have been associated with neurotoxic envenomation in north america. one clinical sign that can occur is myokymia: fine, involuntary, wave-like muscle movements occurring at regular intervals. we report an unusual scenario in which a single snakebite resulted in simultaneous envenomation of 2 patients. both developed myokymia, with 1 having respiratory compromise. one patient also developed a hypersensitivity reaction to antivenom. envenomation by the grand canyon ra ... | 2020 | 32826164 |
| crotalus oreganus concolor: envenomation case with venom analysis and a diagnostic conundrum of myoneurologic symptoms. | a case of midget-faded rattlesnake (crotalus oreganus concolor) envenomation of an adult male professional herpetologist occurred in a rural setting and resulted in an array of venom induced myoneurologic symptoms. the patient experienced blurry vision, total body paresthesia, dyspnea, chest tightness, and waves of spastic muscle movements of the hands and feet that resembled tetany. it was not apparent whether these symptoms were potentially venom induced or were related to stress-induced physi ... | 2020 | 32173212 |
| cooler snakes respond more strongly to infrared stimuli, but we have no idea why. | the pit organ defining pit vipers (crotalinae) contains a membrane covered with temperature receptors that detect thermal radiation from environmental surfaces. temperature is both the environmental parameter being sensed and the mechanism by which the pit membrane detects the signal. as snakes are ectotherms, temperature also has a strong influence on neurological and locomotor responses to the signal. this study of pacific rattlesnakes (crotalus oreganus) systematically examined the effect of ... | 2018 | 29997162 |