Seasonal Pattern of Batrachochytrium dendrobatidis Infection and Mortality in Lithobates areolatus: Affirmation of Vredenburg's “10,000 Zoospore Rule”

To fully comprehend chytridiomycosis, the amphibian disease caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd), it is essential to understand how Bd affects amphibians throughout their remarkable range of life histories. Crawfish Frogs (Lithobates areolatus) are a typical North American pond-breeding species that forms explosive spring breeding aggregations in seasonal and semipermanent wetlands. But unlike most species, when not breeding Crawfish Frogs usually live singly—in nearly total isolation from conspecifics—and obligately in burrows dug by crayfish. Crayfish burrows penetrate the water table, and therefore offer Crawfish Frogs a second, permanent aquatic habitat when not breeding. Over the course of two years we sampled for the presence of Bd in Crawfish Frog adults. Sampling was conducted seasonally, as animals moved from post-winter emergence through breeding migrations, then back into upland burrow habitats. During our study, 53% of Crawfish Frog breeding adults tested positive for Bd in at least one sample; 27% entered breeding wetlands Bd positive; 46% exited wetlands Bd positive. Five emigrating Crawfish Frogs (12%) developed chytridiomycosis and died. In contrast, all 25 adult frogs sampled while occupying upland crayfish burrows during the summer tested Bd negative. One percent of postmetamorphic juveniles sampled were Bd positive. Zoospore equivalents/swab ranged from 0.8 to 24,436; five out of eight frogs with zoospore equivalents near or >10,000 are known to have died. In summary, Bd infection rates in Crawfish Frog populations ratchet up from near zero during the summer to over 25% following overwintering; rates then nearly double again during and just after breeding—when mortality occurs—before the infection wanes during the summer. Bd-negative postmetamorphic juveniles may not be exposed again to this pathogen until they take up residence in crayfish burrows, or until their first breeding, some years later

Liver Enzymes as Biomarkers for Hepatotoxicity of Statins in Patients with Dyslipidemia

Various chemical agents or pharmaceuticals as drugs administered into the body in increased concentrations for a long time may have hepatotoxic or carcinogenic effect. In human biomonitoring are used different biomarkers, which can confirm the presence of various chemical agents in the body and their effects on cells or molecules. The aim of the study is to biomonitoring of the hepatotoxic effects of statins (atorvastatin and rosuvastatin) as a chemical agents or drugs in therapy of patients with dyslipidemia, using biochemical biomarkers as liver enzymes. Materials and methods: Follow-up laboratory tests (AST, ALT, GGT, ALP, cholesterol, and triglycerides) were evaluated with biochemical analyzer Cobas Integra 400 Plus, after 6 months of treatment with statins. The study included 28 subjects, aged 28–84 years (the mean 63.7), 15 women and 13 men, mainly patients with confirm dyslipidemia. Results: The observation of total serum transferases confirmed that 20 of the subjects (71.42%) have a normal serum transferases (AST and ALT) but 8 of the subjects (28.58%) (Groups 1 and 2) have a abnormal level of serum transferases. Subjects in Group 1 (5 subjects with atorvastatin therapy) have an abnormal level of serum transferases (AST and ALT), the mean value of AST was 43.6 U/L and for ALT 73.6 U/L. Subject in Group 2 (3 subjects with rosuvastatin therapy) has >10 times more of the level of AST and ALT (the mean value of AST was 580.3 U/L, and ALT 1802.3 U/L). In the Group 2 we reported older patients (with theages after 60) with long time therapy with rosuvastatin (more than 6 months) who demonstrated significant elevation of ALT according with other chronical diseases as a cardiovascular diseases, diabetes mellitus type 2, acute pancreatitis and in alcohol abusers. Conclusions: We want to emphasize the importance of biomonitoring of liver enzymes as biomarkers which associates hepatotoxicity. Statins therapy (on patients with dyslipidemia) combined with other metabolic drugs and inhibitors, might increase the risk of liver injury. Individual differences, such as sex, age, sensitivity and immune ability, affect the degree of hepatotoxicity of various drugs (in our study statins) as a chemical agents present in the body

Combining BrdU-Labeling to Detection of Neuronal Markers to Monitor Adult Neurogenesis in Hydra

The nervous system is produced and maintained in adult Hydra through the continuous production of nerve cells and mechanosensory cells (nematocytes or cnidocytes). De novo neurogenesis occurs slowly in intact animals that replace their dying nerve cells, at a faster rate in animals regenerating their head as a complete apical nervous system is built in few days. To dissect the molecular mechanisms that underlie these properties, a precise monitoring of the markers of neurogenesis and nematogenesis is required. Here we describe the conditions for an efficient BrdU-labeling coupled to an immunodetection of neuronal markers, either regulators of neurogenesis, here the homeoprotein prdl-a, or neuropeptides such as RFamide or Hym-355. This method can be performed on whole-mount animals as well as on macerated tissues when cells retain their morphology. Moreover, when antibodies are not available, BrdU-labeling can be combined with the analysis of gene expression by whole-mount in situ hybridization. This co-immunodetection procedure is well adapted to visualize and quantify the dynamics of de novo neurogenesis. Upon continuous BrdU labeling, the repeated measurements of BrdU-labeling indexes in specific cellular populations provide a precise monitoring of nematogenesis as well as neurogenesis, in homeostatic or developmental conditions