Effect of Sodium Chloride,Sodium Nitrite and Sodium Nitrate on the Infectivity of Hepatitis E Virus

Food and Environmental Virology - Hepatitis E virus (HEV) infection can cause acute and chronic hepatitis in humans. The zoonotic HEV genotype 3, which is highly prevalent in Europe, is mainly...     

A salamander’s toxic arsenal: review of skin poison diversity and function in true salamanders,genus <Emphasis Type="Italic">Salamandra</Emphasis>

Terrestrial salamanders of the genus Salamandra represent one of the most prominent groups of amphibians. They are mainly distributed across Europe but also reach Northern Africa and the Near East. Members of the six currently accepted species have long been known to be poisonous; however, work on their toxins was mostly published in German language, and therefore, many nuances of these studies have remained hidden from the majority of herpetologists and toxinologists. Several Salamandra species are called fire salamanders due to their highly contrasted, black-yellow colouration which probably serves to deter predators, although thorough evidence for aposematism in Salamandra is still lacking. Salamandra skin toxins do not only represent a potent antipredator defence but may also have antimicrobial effects. A better understanding of this dual function of Salamandra skin secretions is of utmost importance in the face of the emergence of a fungal disease causing catastrophic declines of fire salamanders in Central Europe, caused by the fungus Batrachochytrium salamandrivorans. In this review, we summarize the knowledge on Salamandra toxins, providing a list of the compounds so far isolated from their secretion and focusing on the bioactivity of the major compounds in Salamandra secretions, the steroidal alkaloids. We identify priorities for future research, including a screening of co-occurrence of steroidal alkaloids and tetrodotoxins in salamandrids, chemical characterization of already identified novel steroidal compounds, elucidation of the presence and role of peptides and proteins in the secretion, and experimental in vitro and in vivo study of the interactions between bioactive compounds in Salamandra skin secretions and cutaneous fungal and bacterial pathogens.     

Seasonal changes in eicosanoid metabolism in the brown bear

Polyunsaturated fatty acids (PUFAs) exert several important functions across organ systems. During winter, hibernators divert PUFAs from oxidation, retaining them in their tissues and membranes, to ensure proper body functions at low body temperature. PUFAs are also precursors of eicosanoids with pro- and anti-inflammatory properties. This study investigated seasonal changes in eicosanoid metabolism of free-ranging brown bears (Ursus arctos). By using a lipidomic approach, we assessed (1) levels of specific omega-3 and omega-6 fatty acids involved in the eicosanoid cascade and (2) concentrations of eicosanoids in skeletal muscle and blood plasma of winter hibernating and summer active bears. We observed significant seasonal changes in the specific omega-3 and omega-6 precursors. We also found significant seasonal alterations of eicosanoid levels in both tissues. Concentrations of pro-inflammatory eicosanoids, such as thromboxane B2, 5-hydroxyeicosatetraenoic acid (HETE), and 15-HETE and 18-HETE, were significantly lower in muscle and/or plasma of hibernating bears compared to summer-active animals. Further, plasma and muscle levels of 5,6-epoxyeicosatrienoic acid (EET), as well as muscle concentration of 8,9-EET, tended to be lower in bears during winter hibernation vs. summer. We also found lower plasma levels of anti-inflammatory eicosanoids, such as 15dPGJ₂ and PGE₃, in bears during winter hibernation. Despite of the limited changes in omega-3 and omega-6 precursors, plasma and muscle concentrations of the products of all pathways decreased significantly, or remained unchanged, independent of their pro- or anti-inflammatory properties. These findings suggest that hibernation in bears is associated with a depressed state of the eicosanoid cascade.