Evidence of Batrachochytrium dendrobatidis Infection in Amphibians from Serbian Lowlands

A Variety of Fungal Species on the Green Frogs' Skin (Pelophylax esculentus complex) in South Banat

In the last several decades, amphibian populations have been declining worldwide. Many factors have been linked to global amphibian decline, including habitat destruction, pollution, introduced species, global environmental changes, and emerging infectious diseases. Recent studies of amphibian skin infections were mainly focused on the presence of chytridiomycosis, neglecting other members of the frogs' skin communities. The diversity pattern of fungal dwellers on the skin of green frogs (Pelophylax esculentus complex) was investigated. A total of 100 adults were sampled from three localities in South Banat (northern Serbia) over three consecutive years and detected fungal dwellers were identified using light microscopy and ITS and BenA gene sequencing. Structures belonging to fungi and fungus-like organisms including a variety of spores and different mycelia types were documented in the biofilm formed on amphibian skin, and are classified into 10 groups. In total, 42 fungal isolates were identified to species, section, or genus level. The difference in mycobiota composition between sampling points (localities and green frog taxa) was documented. The highest number of fungal structures and isolates was recorded on the hybrid taxon P. esculentus and locality Stevanove ravnice. Parental species showed a markedly lower diversity than the hybrid taxon and were more similar in diversity patterns and were placed in the same homogenous group. The locality Stevanove ravnice exhibited more pronounced differences in diversity pattern than the other two localities and was placed in a distinct and separate homogenous group. Among the fungal isolates, the highest isolation frequency was documented for Alternaria alternata, Aspergillus sp. sect. Nigri, Epicoccum nigrum, Fusarium proliferatum, and Trichoderma atroviride. Among the documented species, dematiaceous fungi, causative agents of chromomycosis in amphibians, were also recorded in this research with high isolation frequency. Also, some rare fungal species such as Quambalaria cyanescens and Pseudoteniolina globosa are documented for the first time in this research as microbial inhabitants of amphibian skin.

Tetrahydroxystilbene Glucoside Delayed Senile Symptoms in Old Mice via Regulation of the AMPK/SIRT1/PGC-1α Signaling Cascade

BACKGROUND

Tetrahydroxystilbene glucoside (TSG) is a main bioactive component of Polygonum multiflorum, a traditional Chinese medicine known for certain anti-aging effects. Since TSG has been found to extend lifespan in the nematode Caenorhabditis elegans, we hypothesized that TSG might produce anti-aging benefits in mammals.

OBJECTIVE

The aim was to evaluate the anti-aging potential of TSG and to explore its relative molecular mechanism.

METHODS

Mice were maintained on standard diet, high-calorie diet (HC), or high-calorie plus TSG diet. Survival rates and body weight changes were recorded weekly. Rotarod analysis was performed to assess the physical fitness of mice. Bone mineral density was assessed using micro-computed tomography. Hematoxylin and eosin staining was used for the histological examination of heart, liver, and kidney pathology. The mRNA and protein expression of target genes were analyzed by quantitative real-time polymerase chain reaction and western blotting, respectively. Mitotracker deep red staining and high-content analysis were used to quantify cellular mitochondrial mass and function.

RESULTS

In this study, we found that TSG improved the physiology of aged mice consuming excess calories and delayed senile symptoms. The anti-aging benefits of TSG were mediated at least in part by the AMP-activated protein kinase (AMPK)/sirtuin 1 (SIRT1)/peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α) signaling cascade, leading to significant improvement in motor function, bone mineral density, HC-induced organ pathology, and mitochondrial function.

CONCLUSION

Our findings show that TSG could be a potential drug candidate for the treatment of aging- and high-calorie intake-associated disorders.