L-amino acid oxidase from Naja atra venom activates and binds to human platelets

An L-amino acid oxidase (LAAO), NA-LAAO, was purified from the venom of Naja atra. Its N-terminal sequence shows great similarity with LAAOs from other snake venoms. NA-LAAO dose-dependently induced aggregation of washed human platelets. However, it had no activity on platelets in platelet-rich plasma. A low concentration of NA-LAAO greatly promoted the effect of hydrogen peroxide, whereas hydrogen peroxide itself had little activation effect on platelets. NA-LAAO induced tyrosine phosphorylation of a number of platelet proteins including Src kinase, spleen tyrosine kinase, and phospholipase Cgamma2. Unlike convulxin, Fc receptor gamma chain and T lymphocyte adapter protein are not phosphorylated in NA-LAAO-activated platelets, suggesting an activation mechanism different from the glycoprotein VI pathway. Catalase inhibited the platelet aggregation and platelet protein phosphorylation induced by NA-LAAO. NA-LAAO bound to fixed platelets as well as to platelet lysates of Western blots. Furthermore, affinity chromatography of platelet proteins on an NA-LAAO-Sepharose 4B column isolated a few platelet membrane proteins, suggesting that binding of NA-LAAO to the platelet membrane might play a role in its action on platelets.

Assessment of the prevalence of Trichinella spp. in red foxes and Eurasian lynxes from Switzerland

Trichinella spp. larvae have not been detected in Swiss pigs, horses, or wild boar for many decades, whereas the parasite was repeatedly isolated from red foxes and Eurasian lynxes. Whenever the isolated larvae could be subjected to genotyping, T. britovi was found as infective agent. The present study was initiated to re-assess the epidemiological situation of Trichinella infection in Swiss carnivorous wildlife, namely in red foxes and lynxes. Tissue samples from 1,298 foxes were collected between 2006 and 2007, and those of 55 lynxes between 1999 and 2007. All samples were tested by a standard artificial digestion method and a multiplex-PCR to determine the species and/or genotypes of recovered larvae. Trichinella larvae were found in 21 foxes (1.6%) and 15 lynxes (27.3%), and T. britovi was identified as infecting species in all cases. The geographic distribution of positive foxes showed two main clusters: one in Central Switzerland and one in the West of the country, where also many lynxes were found to be positive. While the prevalence for Trichinella infection in foxes was not statistically correlated with sex or age class, the prevalence in lynx was significantly higher in males compared to females, and in adults compared to juveniles.

Optimizing the size of the area surveyed for monitoring a Eurasian lynx (Lynx lynx) population in the Swiss Alps by means of photographic capture-recapture

We studied the influence of surveyed area size on density estimates by means of camera-trapping in a low-density felid population (1-2 individuals/100 km(2) ). We applied non-spatial capture-recapture (CR) and spatial CR (SCR) models for Eurasian lynx during winter 2005/2006 in the northwestern Swiss Alps by sampling an area divided into 5 nested plots ranging from 65 to 760 km(2) . CR model density estimates (95% CI) for models M0 and Mh decreased from 2.61 (1.55-3.68) and 3.6 (1.62-5.57) independent lynx/100 km(2) , respectively, in the smallest to 1.20 (1.04-1.35) and 1.26 (0.89-1.63) independent lynx/100 km(2) , respectively, in the largest area surveyed. SCR model density estimates also decreased with increasing sampling area but not significantly. High individual range overlaps in relatively small areas (the edge effect) is the most plausible reason for this positive bias in the CR models. Our results confirm that SCR models are much more robust to changes in trap array size than CR models, thus avoiding overestimation of density in smaller areas. However, when a study is concerned with monitoring population changes, large spatial efforts (area surveyed ≥760 km(2) ) are required to obtain reliable and precise density estimates with these population densities and recapture rates.

Immunoblotting for the serodiagnosis of alveolar echinococcosis in alive and dead Eurasian beavers (Castor fiber)

A novel species-specific anti-beaver-IgG-alkaline-phosphatase conjugate was synthesized for the development of a new serological test for echinococcosis in beavers. Two different ELISAs conventionally used for human Echinococcus multilocularis serology (Em18-ELISA and Em2-ELISA) yielded diagnostic sensitivities of 0% and 46%, respectively. In contrast, the subsequently developed immunoblotting assay gave an 85% diagnostic sensitivity (11 out of 13 beavers with alveolar echinococcosis were immunoblotting-positive, i.e. showed reactivity with a specific 21 Mr band), and maximal specificity. In conclusion, this immunoblotting assay should be the method of choice for use in serological studies on E. multilocularis in Eurasian beavers, and the test proved suitable to investigate both animals alive and post-mortem.

Scent-marking behaviour and social dynamics in a wild population of Eurasian lynx Lynx lynx.

Scent-marking is widespread among mammals and has been observed in many felid species. Although the behaviour is well-described, little is known about its function in wild felid populations. We investigated patterns of scent-marking and its role in intra- and intersexual communication among resident and non-resident Eurasian lynx Lynx lynx by observing interactions among wild lynx at natural marking sites by means of infrared camera traps. Marking activity of resident animals showed a peak during the mating season and was lowest during the time when females gave birth and lactated. Both sexes scent-marked, but male lynx visited marking sites much more often than females and marked relatively more often when visiting a site. Most visits to marking sites were by residents but we also observed scent-marking by non-residents. Juveniles were never observed marking. We found no evidence of lynx regularly renewing scent-marks after a certain 'expiry date' but the presence of a strange scent-mark triggered over-marking. Males responded similarly to the presence of another individual's scent-mark, irrespective of whether it was the top- or the underlying scent-mark in a mixture of scent-marks they encountered. Our results suggest that marking sites could serve as 'chemical bulletin boards', where male lynx advertise their presence and gain information on ownership relationships in a given area. Females placed their urine marks on top of the ones left by resident males, but further studies are needed to explain the functions of over-marking in females.

The First Density Estimation of an Isolated Eurasian Lynx Population in Southwest Asia

During November 2010–February 2011, we used camera traps to estimate the population density of Eurasian lynx Lynx lynx in Ciglikara Nature Reserve, Turkey, an isolated population in southwest Asia. Lynx density was calculated through spatial capture—recapture models. In a sampling eff ort of 1093 camera trap days, we identifi ed 15 independent individuals and estimated a density of 4.20 independent lynx per 100 km2, an unreported high density for this species. Camera trap results also indicated that the lynx is likely to be preying on brown hare Lepus europaeus, which accounted for 63% of the non-target species pictured. As lagomorph populations tend to fl uctuate, the high lynx density recorded in Ciglikara may be temporary and may decline with prey fl uctuation. Therefore we recommend to survey other protected areas in southwestern Turkey where lynx is known or assumed to exist, and continuously monitor the lynx populations with reliable methods in order to understand the populations structure and dynamics, defi ne sensible measures and management plans to conserve this important species.