Silymarin is an extract obtained from the seeds of milk thistle (Sylibum marianum L., Asteraceae) and contains several structurally related flavonolignans and a small family of flavonoids. Mouse spleen cells represent highly sensitive primary cells suitable for studying the pharmacological potential and biofunctional properties of natural substances. Cultivation of splenocytes for 24 h under standard culture conditions (humidity, 37 °C, 5% CO2, atmospheric oxygen) resulted in decreased viability of splenocytes compared to intact cells. A cytoprotective effect of silybin (SB), silychristin (SCH) and 2,3-dehydrosilybin (DHSB) was observed at concentrations as low as 5 µmol/ml. At 50 µmol/ml, these substances restored and/or stimulated viability and mitochondrial membrane potential and had anti-apoptotic effect in the order SB > DHSB > SCH. The substances demonstrated a concentration-dependent activity in restoring the redox balance based on the changes in the concentration of reactive oxygen species (ROS), hydrogen peroxide (H2O2) and nitric oxide. This was in the order DHSB > SCH > SB, which correlated with the suppressed expression of nuclear factor erythroid 2-related factor 2 (Nrf2), catalase and glutathione peroxidase. The strong stimulation of the superoxide dismutase 1 gene converting ROS to H2O2 points to its dominant role in the maintaining redox homeostasis in splenocytes, which was disrupted by oxidative stress due to non-physiological culture conditions. Our study showed significant differences in the cytoprotective, antioxidant and anti-apoptotic activities of SB, SCH, and DHSB on splenocytes exposed to mild and AAPH-induced oxidative stress.

• Klíčová slova
• 2,3-dehydrosilybin, Apoptosis, Mouse splenocytes, Redox balance, Silybin, Silychristin, Viability,
• MeSH
• antioxidancia * farmakologie   MeSH
• apoptóza * účinky léků   MeSH
• cytoprotekce účinky léků   MeSH
• membránový potenciál mitochondrií účinky léků   MeSH
• myši inbrední BALB C * MeSH
• myši MeSH
• oxidační stres účinky léků   MeSH
• peroxid vodíku MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• silibinin * farmakologie   MeSH
• silymarin * farmakologie   MeSH
• slezina * cytologie   účinky léků   metabolismus   MeSH
• viabilita buněk účinky léků   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antioxidancia * MeSH
• peroxid vodíku MeSH
• reaktivní formy kyslíku MeSH
• silibinin * MeSH
• silychristin MeSH Prohlížeč
• silymarin * MeSH

Coexistence of species with similar requirements is allowed, among others, through trade-offs between competitive ability and other ecological traits. Although interspecific competition is based on two mechanisms, exploitation of resources and physical interference, trade-off studies largely consider only species' ability to exploit resources. Using a mesocosm experiment, we examined the trade-off between interference competition ability and susceptibility to predation in larvae of two newt species, Ichthyosaura alpestris and Lissotriton vulgaris. In the presence of heterospecifics, L. vulgaris larvae slowed somatic growth and developmental rates, and experienced a higher frequency of injuries than in conspecific environments which suggests asymmetrical interspecific interference. During short-term predation trials, L. vulgaris larvae suffered higher mortality than I. alpestris. Larvae of the smaller species, L. vulgaris, had both lower interference and antipredator performance than the larger I. alpestris, which suggests a lack of trade-off between interference competition ability and predator susceptibility. We conclude that interference competition may produce a positive rather than negative relationship with predation susceptibility, which may contribute to the elimination of subordinate species from common habitats.

• Klíčová slova
• amphibians, interspecific aggression, predator‐prey interaction, somatic growth, species coexistence,
• Publikační typ
• časopisecké články MeSH

It has been proposed that digit ratio may be used as a biomarker of early developmental effects. Specifically, the second-to-fourth digit ratio (2D:4D) has been linked to the effects of sex hormones and their receptor genes, but other digit ratios have also been investigated. Across taxa, patterns of sexual dimorphism in digit ratios are ambiguous and a scarcity of studies in basal tetrapods makes it difficult to understand how ratios have evolved. Here, we focus on examining sex differences in digit ratios (2D:3D, 2D:4D, and 3D:4D) in a common amphibian, the fire salamander (Salamandra salamandra). We used graphic software to measure soft tissue digit length and digit bone length from X-rays. We found a nonsignificant tendency in males to have a lower 2D:3D than females; however, no sexual differences were detected in the other ratios. We discuss our results in the context of other studies of digit ratios, and how sex determination systems, as well as other factors, might impact patterns of sexual dimorphism, particularly in reptiles and in amphibians. Our findings suggest that caution is needed when using digit ratios as a potential indicator of prenatal hormonal effects in amphibians and highlight the need for more comparative studies to elucidate the evolutionary and genetic mechanisms implicated in sexually dimorphic patterns across taxonomic groups.

• Klíčová slova
• Salamandridae, amphibians, digit ratios, image analysis,
• MeSH
• pohlavní dimorfismus * MeSH
• přední končetina anatomie a histologie   diagnostické zobrazování   MeSH
• prsty nohy anatomie a histologie   diagnostické zobrazování   MeSH
• rentgendiagnostika MeSH
• Salamandra MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Many ectotherms effectively reduce their exposure to low or high environmental temperatures using behavioral thermoregulation. In terrestrial ectotherms, thermoregulatory strategies range from accurate thermoregulation to thermoconformity according to the costs and limits of thermoregulation, while in aquatic taxa the quantification of behavioral thermoregulation have received limited attention. We examined thermoregulation in two sympatric newt species, Ichthyosaura alpestris and Lissotriton vulgaris, exposed to elevated water temperatures under semi-natural conditions. According to a recent theory, we predicted that species for which elevated water temperatures pose a lower thermal quality habitat, would thermoregulate more effectively than species in thermally benign conditions. In the laboratory thermal gradient, L. vulgaris maintained higher body temperatures than I. alpestris. Semi-natural thermal conditions provided better thermal quality of habitat for L. vulgaris than for I. alpestris. Thermoregulatory indices indicated that I. alpestris actively thermoregulated its body temperature, whereas L. vulgaris remained passive to the thermal heterogeneity of aquatic environment. In the face of elevated water temperatures, sympatric newt species employed disparate thermoregulatory strategies according to the species-specific quality of the thermal habitat. Both strategies reduced newt exposure to suboptimal water temperatures with the same accuracy but with or without the costs of thermoregulation. The quantification of behavioral thermoregulation proves to be an important conceptual and methodological tool for thermal ecology studies not only in terrestrial but also in aquatic ectotherms.

• MeSH
• druhová specificita MeSH
• fyziologická adaptace * MeSH
• Salamandridae fyziologie   MeSH
• sympatrie fyziologie   MeSH
• tělesná teplota MeSH
• termoregulace fyziologie   MeSH
• voda * MeSH
• vysoká teplota * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• voda * MeSH