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Results for “Colubridae”

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At least 487 records · Page 27Linked to original sources
PubMed2003

Edematogenic and myotoxic activities of the Duvernoy's gland secretion of Philodryas olfersii from the north-east region of Argentina.

Philodryas olfersii is found in South America, from Amazonas to Patagonia. It is important to characterize the venom of P. olfersii, who inhabits the North-East region of Argentina, since snake venoms are known to exhibit considerable variability in composition and biological activities. In this work, mice weighing 18-20 g (n = 4 for each experimental group) were used. For the edematogenic activity mice were injected s.c. in the right foot pad with 50 microl of solutions containing different amounts of venom, whereas the left foot pad was injected with 50 microl of PBS. Two hours after injection mice were killed by cervical dislocation and both feet were cut off and weighed individually. For the myotoxic activity mice were injected i.m. with 100 microl of solutions containing 40 microg of venom. Blood samples were extracted after 1, 3, 6, 8, 10, 12, 14, 16 and 24 h of venom injection to determinate serum CPK activity and mice were sacrificed at the same time intervals to obtain the inoculated gastrocnemius muscle. They were fixed with Bouin solution and stained with Hematoxylin-Eosin. Results showed that P. olfersii venom exhibits a high edematogenic activity (MED = 0.31 microg) and a moderate myotoxic activity. Myonecrosis reached its highest level after 12 h of venom injection as shown by plasmatic CPK levels (5,401 +/- 330 IU/l) and microscopic assay. It demonstrates the potential toxicity of the venom of P. olfersii, who inhabits the North-East region of Argentina. It also reinforces the original warning concerning the potential danger of bites by colubrids.

Animals↗
PubMed2004

Bites by the grass snake Natrix natrix.

The non life-threatening results of a bite from a grass snake in a 17-y-old patient are described, their significance evaluated, and the hazard of such bites discussed.

Adolescent↗
PubMed2005

Does large body size in males evolve to facilitate forcible insemination? A study on garter snakes.

A trend for larger males to obtain a disproportionately high number of matings, as occurs in many animal populations, typically is attributed either to female choice or success in male-male rivalry; an alternative mechanism, that larger males are better able to coercively inseminate females, has received much less attention. For example, previous studies on garter snakes (Thamnophis sirtalis parietalis) at communal dens in Manitoba have shown that the mating benefit to larger body size in males is due to size-dependent advantages in male-male rivalry. However, this previous work ignored the possibility that larger males may obtain more matings because of male-female interactions. In staged trials within outdoor arenas, larger body size enhanced male mating success regardless of whether a rival male was present. The mechanism involved was coercion rather than female choice, because mating occurred most often (and soonest) in females that were least able to resist courtship-induced hypoxic stress. Males do physically displace rivals from optimal positions in the mating ball, and larger males are better able to resist such displacement. Nonetheless, larger body size enhances male mating success even in the absence of such male-male interactions. Thus, even in mating systems where males compete physically and where larger body size confers a significant advantage in male-male competition, the actual selective force for larger body size in males may relate to forcible insemination of unreceptive females. Experimental studies are needed to determine whether the same situation occurs in other organisms in which body-size advantages have been attributed to male-male rather than male-female interactions.

Aggression↗
PubMed2006

Culex neavei Theobald, as a possible transmitter of Hepatozoon matruhensis to the Egyptian snake Psammophis schokari.

Stained smears of Culex neavei females infected with Hepattozoon matruhensis from Psammophis schokari and kept at 20 +/- 1 degrees C showed the complete developmental stages of the parasite. However, no detection of sporozoites was monitored when females were kept at 30 +/- 1 degrees C. A successful infection of P. schokari was carried out in the laboratory by C. neavei bites. The effect of infection on the mosquito longevity was insignificant (p>0.05) under low temperature and highly significant (p<0.001) under high temperature. The mortality rate was slightly affected at 20 +/- 1 degrees C, but greatly affected at 30 +/- 1 degrees C.

Animals↗
PubMed1995

Tissue and serum enzyme activities in the yellow rat snake (Elaphe obsoleta quadrivitatta).

Activities of diagnostically important enzymes were measured in serum and lysates of liver, kidney, skeletal muscle, heart, intestine, lung, and pancreatic tissues from wild-caught yellow rat snakes, Elaphe obsoleta quadrivitatta. All samples were analyzed for alkaline phosphatase, lactate dehydrogenase (LD), aspartate transaminase (AST), alanine transaminase, gamma-glutamyltransferase, and creatine kinase (CK) activities. The major enzyme activities found in the liver were LD and AST. The kidney had moderate activities of LD, AST, alanine transaminase, and CK. Skeletal muscle and heart contained high CK activity. Intestine, lung, and pancreas had low activities for most enzymes analyzed. Little to no gamma-glutamyltransferase activity was found in serum or tissues analyzed. Serum enzyme activities in yellow rat snakes were similar to those described for other reptile species, except for serum CK activity, which was increased in rat snakes.

Alanine Transaminase↗
PubMed1994

Seasonal changes in spermatogenesis and ultrastructure of developing spermatids in the Japanese rat snake, Elaphe climacophora.

Seasonal changes in spermatogenesis and the ultrastructure of developing spermatids in the Japanese rat snake, Elaphe climacophora, were observed by light and transmission electron microscopy. Spermatogenesis in this species began in August, continued through October and ceased in November. No spermatozoa were found during other periods. Japanese rat snakes mate from May to July, and spermatogenesis occurs after the mating season. Therefore, according to Girons' classification (1982), the reproduction of this species was classified as a postnuptial type. Although the morphological changes in developing spermatids during spermiogenesis in these snakes fundamentally resembled those in mammals, some unique features were detected. The most prominent characteristic of the developing spermatids was lipid-like structures. These structures first appeared in early round spermatids, gradually increased in size and number, and, finally, aligned around the nucleus of mature spermatids. Although spermatozoa with lipid-like structures were released from the epithelium, stored spermatozoa in vas deferenses had none of these structures. Lipid-like structures that apparently separated from spermatozoa were scattered in the vas deferens. Prominent elongation of mitochondria was also remarkable in elongated spermatids.

Acrosome↗
PubMed1994

Experimental infection of elaphid snakes with Cryptosporidium serpentis (Apicomplexa: Cryptosporidiidae).

The shedding pattern of fecal Cryptosporidium serpentis oocysts, histopathologic changes in the gastric region, and the effect of spiramycin treatment were investigated in 6 experimentally infected, captive black rat (Elaphe obsoleta obsoleta), 4 yellow rat (Elaphe obsoleta quadrivittata), and 2 corn snakes (Elaphe guttata guttata). Feces were monitored for up to 2 years postinfection (PI). No significant (P > 0.07) differences were observed between expected and observed numbers of PI oocyst-positive feces. Two of 5 control animals acquired natural infections of C. serpentis over the period of study. No morphological differences were observed between oocysts from experimental and natural infections. Clinical signs included postprandial regurgitation in 5 of 13 (38%) snakes, not coinciding with the shedding of fecal oocysts. Midbody swelling and self-cure were not observed. Spiramycin treatment of 4 of 12 experimentally infected animals resulted in negative fecal examinations in 2 snakes and reduced the percentage of oocyst-positive feces in 2 other snakes from 75.5% to 24.5% and from 83.9% to 33.6%. Biopsies and necropsies revealed stages of Cryptosporidium in the gastric mucosa of all spiramycin-treated animals. The gastric mucosa was thickened and edematous, with focal necrosis, mucosal petechiae, and brush hemorrhages. Fibroplasia of lamina propria associated with chronic mucosal inflammation were common. Examination of direct fecal smears was found not to be a reliable technique for diagnosis of cryptosporidial infections in snakes.

Analysis of Variance↗
PubMed1994

Snake bites in Zimbabwe: a clinical study with emphasis on the need for antivenom.

A retrospective analysis of 83 consecutive patients (42 males and 41 females) treated for snake bites at Mpilo Central Hospital between January 1990 and June 1992 is presented. In Zimbabwe poisonous snakes belong to four families; Colubrids (Boomslang), Vipers (Puff Adder), Elapids (Mambas and Cobras) and Atractaspids (Bibron Stilleto snake). The Puff Adder is responsible for three quarters of the bites. Forty eight pc (40/83) of the patients were below 20 years of age (range 1 year 10 months to 72 years). Most bites occurred at night (61 pc) in the rainy season (November to April). The majority of snake bites occurred on the lower limb, 64 pc (53/83), with most of the remainder occurring on the upper limb, 34 pc (28/83). The most common clinical features were; pain (95 pc), swelling (87 pc), tachycardia (20 pc), fever (13 pc) and vomiting (8 pc). This study, carried out at a time when there was no antivenom in stock at Mpilo Hospital, shows a considerable mortality (5 pc, 4/83) and morbidity (37 pc, 31/83) rate from poisonous snake bites in Zimbabwe. These observations highlight the need to maintain adequate stocks of antivenom in the major hospitals in Zimbabwe.

Adolescent↗
PubMed1994

Properties of "reconstructed" motor synapses of the garter snake.

We have developed a technique, called synaptic reconstruction, that permits nerve terminals of living vertebrate neuromuscular junctions (NMJs) to be isolated and then manually recombined with vacant endplate sites to form functional synapses. By reconstructing NMJs with various combinations of pre- and postsynaptic partners, or with varying degrees of pre- to postsynaptic alignment, the functional properties of the three anatomical components of the NMJ--nerve terminal, endplate, and the alignment between them--may be studied independently. Our experiments thus far indicate, surprisingly, that reconstructed NMJs function nearly normally. Thus, one feature of the intact vertebrate NMJ, precise alignment between presynaptic active zones and postsynaptic secondary folds, is either unnecessary for normal function or, alternatively, is spontaneously reestablished when an isolated terminal and vacant endplate site are placed in contact. We have also utilized synaptic reconstruction to examine a recently described property of NMJs: the regulation of quantal size among motor synapses in one muscle so that larger muscle fibers receive larger single quantal currents. Quantal size appears to be a postsynaptic attribute, suggesting that its regulation is achieved by a postsynaptic mechanism.

Animals↗
PubMedDate not supplied

[A comparative study of the content of peripheral and integral proteins in the liver microsomal membranes of vertebrates].

Peripheral and integral protein amounts in liver microsomal membranes of 11 species of vertebrate animals have been investigated. It was found that the peripheral protein content increases in the following sequence: fishes, amphibians, reptiles, birds. The content of integral proteins decreases in the same sequence. The content of proteins in liver membranes from mammals corresponds to that from lower vertebrates.

Animals↗