James L. Glenn

Geographical variation in Crotalus scutulatus scutulatus (Mojave rattlesnake) venom properties

Individual venom samples were analyzed from 12 specimens of Crotalus scutulatus scutulatus, from north of Tucson to the extreme southeastern region of Arizona. Six of the specimens, from north of Tucson, produced venom lethal toxicity (i.p. LD50) values in mice of 2.0-6.0 mg/kg. These coincided with the values previously reported for C. s. scutulatus in the Phoenix, Arizona, region and designated as type B venom (Glenn and Straight, 1978). In contrast, the venom LD50 of six individuals from extreme southeastern Arizona, including one individual near Tucson, ranged from 0.22-0.46 mg/kg. This corresponds to the values for C. s. scutulatus venom previously reported and designated as type A venom (Glenn and Straight, 1978). Specimens with type A venom have been collected in California, Nevada, Utah and regions of Arizona. In addition to differences in lethal toxicity, the type B venom consistently exhibits a different protein profile, greater proteolytic activity, greater hemorrhagic activity and contains little or none of the major lethal toxin, Mojave toxin, compared to the type A venom. No external morphological characteristic could be found differentiating the type A venom specimens from the type B venom specimens. These findings further confirm the geographical variation of C. s. scutulatus venom in Arizona.

Detection of myotoxin a-like proteins in various snake venoms

Ninety-five venom samples from eight snake genera (Agkistrodon, Bitis, Bothrops, Calloselasma, Crotalus, Sistrurus, Naja and Vipera) including venoms of Crotalus species of different geographical origin were assayed using immunodiffusion or an ELISA for the presence of the small basic protein, myotoxin alpha, known to cause muscle necrosis. Of the eight genera investigated, only Crotalus and Sistrurus venoms contained detectable amounts of myotoxin alpha-like proteins. The venoms of 13 out of 17 rattlesnake species investigated contained proteins immunologically similar to myotoxin alpha, including 12 Crotalus species and one Sistrurus species. The highest amounts were detected in venoms of C. exsul, C. viridis oreganus and C. v. viridis. Qualitative differences in the presence or absence of myotoxin alpha-like proteins were observed in the venoms of C. cerastes, C. horridus, C. lepidus, C. mitchelli, C. scutulatus, C. viridis and S. catenatus specimens of different geographic origin. The toxin was not detected in the venoms obtained from C. adamanteus, C. atrox, C. enyo or C. vegrandis specimens. The toxin appears to be widely distributed among rattlesnake species in the new world, but may vary qualitatively by geographical region in several species and subspecies.

The midget faded rattlesnake (Crotalus Viridis Concolor) venom: Lethal toxicity and individual variability☆

Abstract The midget faded rattlesnake ( Crotalus viridis concolor ) venom: lethal toxicity and individual variability. Toxicon 15, 129–133, 1977.— Crotalus viridis concolor venoms were collected from captive specimens from northeastern Utah and tested for lethal potency in mice and for protein content by polyacrylamide gel electrophoresis. We found C. v. concolor potency (i.p.- ld 50 -0·25 μg per g) comparable to Crotalus durisses terrificus (i.p.- ld 50 -0·25 μg) and Crotalus scutulatus scutulatus (California variety) (i.p.- ld 50 -0·24 μg per g) venoms. Individual C. v. concolor venoms show a wide variability both in lethality and protein pattern. The venom appears to be one of the most lethal Crotalid venoms in the New World.

Comparative enzymatic study of HPLC-fractionated Crotalus venoms

1. Ten venoms of the genus Crotalus (Crotalus adamanteus, Crotalus atrox, Crotalus durissus durissus, Crotalus horridus horridus, Crotalus lepidus, Crotalus polystictus, Crotalus molossus molossus, Crotalus pusillus, Crotalus scutulatus scutulatus, venom B, and Crotalus viridis lutosus) were fractionated using HPLC anion and cation exchange chromatography. 2. HPLC venom fractions were tested for hemorrhagic, hemolytic, and proteolytic activities. 3. Crude Virginia opossum (Didelphis virginiana) serum neutralized the hemorrhagic activity of HPLC fractions.

Yield of venom obtained from Crotalus atrox by electrical stimulation.

Abstract Venom was collected from 150 freshly caught specimens of Crotalus atrox . Quantity and quality of venom produced were studied as a function of length of time in captivity, feeding, size of the snake and frequency of venom extraction by electrical stimulation of the mandibulae compressor glandulae muscles. The volume of venom collected from Crotalus atrox and other venomous snakes was increased by electrical venom extraction (EVE) without altering the quality of the venom or injuring the snake. The first EVE on freshly caught snakes yielded relatively low and highly variable volumes. Fasted snakes produced more venom at a faster rate than force-fed snakes. EVE of rested and fasted snakes was found to be an excellent way to obtain large amounts of venom for research.

Regional differences in content of small basic peptide toxins in the venoms of Crotalus adamanteus and Crotalus horridus.

1. Reverse-phase HPLC and organic solvents were used to isolate small basic peptide (SBP) toxins from the venoms of Crotalus adamanteus, C. durissus terrificus, C. horridus, C. scutulatus scutulatus, C. viridis concolor, C. viridis helleri and C. viridis viridis. 2. Acid-DEP analyses indicated a high degree of toxin purity which was obtained with a single HPLC run. 3. The combined results of HPLC, immunodiffusion and electrophoresis analyses of venoms from different geographical regions indicate that the SBP toxin content in the venoms of Crotalus adamanteus, Crotalus horridus, Crotalus scutulatus and Crotalus viridis viridis may vary regionally.

Regional variation of biochemical characteristics and antigeneity in great basin rattlesnake (Crotalus viridis lutosus) venom

1. Three pooled and 20 individual venom samples of Crotalus viridis lutosus from different localities in Utah and Arizona were screened and fractionated with HPLC-anion exchange. 2. Pooled venom samples and fractions were tested for hemorrhagic, collagenase, and phospholipase activities, and reactivity to a monoclonal antibody against a hemorrhagin from C. atrox venom (CA-P-8) using ELISA. 3. The 20 individual samples were organized into four groups based on their HPLC profiles. 4. ELISA results and specific hemorrhagic activity of the venom samples displayed a variation in latitidinal distribution although from the same species.

North-south regional variation in phospholipase a activity in the venom of crotalus ruber

1. Twenty-seven individual venoms from the rattlesnake species Crotalus ruber from different regions were comparatively analyzed by reverse-phase HPLC and analyzed for phospholipase A (PLA) content using a polarographic assay. 2. Two fractions containing PLA activity were detected by HPLC in the venoms of all the C. ruber specimens from southern Baja, Mexico, but specimens from southern California, U.S.A., were lacking corresponding fractions and were extremely low or lacking in PLA activity in their venoms. 3. The north-south regional variation in PLA content in C. ruber venom does not correlate with the north-south ranges (based on external morphology) of the subspecies C. ruber ruber and C. ruber lucasensis.