Variation in microplastic characteristics among amphibian larvae: a comparative study across different species and the influence of human activity.

Microplastic pollution is a significant global environmental issue, and impacts span from individual organisms to the entire ecosystems. This study investigated the properties of microplastics in amphibian larvae, shedding light on their environmental interactions and potential ecological consequences. We examined microplastics extracted from amphibian larvae of 10 taxa, sampled from sites experiencing different levels of human impact. Our findings revealed a predominance of blue microplastics and fibres, each comprising 53% of the total microplastics in amphibian larvae. Microplastic fibres were also notably longer than other morphological types of microplastics. Furthermore, we observed variations in the surface area of microplastics among different amphibian families. An interesting observation from our research is the apparent positive relationship between the size of amphibian larvae and the length of granular and flake-shaped microplastics. Conversely, we observed a negative relationship between the length of these microplastics and human environmental impact. These insights significantly contribute to the understanding of microplastic pollution in freshwater environments, highlighting its complexities beyond marine ecosystems. Our research emphasises the intricate relationships between microplastics and freshwater organisms, underscoring the need for comprehensive strategies to mitigate microplastic pollution.

Similarity of Microplastic Characteristics between Amphibian Larvae and Their Aquatic Environment.

Microplastics, pervasive environmental pollutants, are found across various ecosystems, including small inland water bodies. They are reported in different environmental media, yet little is known about the mutual relationships of microplastics' properties across components of small inland water bodies. Here, having extracted and analyzed these particles from water, sediment, and amphibian larvae from 23 sites, we test within-site similarities regarding shape (morphological type), color, and chemical composition (polymer type). We also provide a brief characterization of the microplastics extracted from water and sediment regarding these parameters. We observed a statistically significant similarity of microplastics' shapes and colors between those extracted from water and amphibian larvae. Such a similarity, though less pronounced, was also found between amphibian larvae and sediment. However, the chemical composition (polymer type) of the microplastics from water, sediment, and amphibian larvae did not exhibit any similarities beyond what would be expected by chance. The observed congruence in the colors and shapes of microplastics between amphibian larvae and their corresponding aquatic habitats underscores the profound interconnectedness among the constituents of freshwater ecosystems.

Climatic conditions and prevalence of melanistic snakes-contrasting effects of warm springs and mild winters.

Climate change is one of the greatest challenges that wildlife is facing. Rapid shifts in climatic conditions may accelerate evolutionary changes in populations as a result of strong selective pressure. Most studies focus on the impact of climatic conditions on phenologies and annual cycles, whereas there are fewer reports of empirical support for climate-driven changes in the phenotypic variability of free-living populations. We investigated whether climatic variables explain the prevalence of colour polymorphism in a population of the grass snake (Natrix natrix) with two morphotypes, the melanistic and non-melanistic ones, in the period 1981-2013. We found that the prevalence of the black phenotype was negatively related to spring temperature and winter harshness, expressed as the number of snow days. According to the thermal melanism hypothesis, a high predation rate during warmer springs may override relaxed thermal benefits and vice versa, i.e. black individuals may perform better than typical ones when thermal conditions in spring are unfavourable. In turn, because they are smaller, melanistic individuals may be exposed to a higher risk of winter mortality, particularly during longer winters. We highlight the need for more studies on the effects of climatic conditions on temporal variation in melanism prevalence in other populations and species as well as in various geographic regions.

Lipid droplets in skeletal muscle during grass snake (Natrix natrix L.) development.

Lipid droplets (LDs) are common organelles observed in Eucaryota. They are multifunctional organelles (involved in lipid storage, metabolism, and trafficking) that originate from endoplasmic reticulum (ER). LDs consist of a neutral lipid core, made up of diacyl- and triacylglycerols (DAGs and TAGs) and cholesterol esters (CEs), surrounded by a phospholipid monolayer and proteins, which are necessary for their structure and dynamics. Here, we report the protein and lipid composition as well as characterization and dynamics of grass snake (Natrix natrix) skeletal muscle LDs at different developmental stages. In the present study, we used detailed morphometric, LC-MS, quantitative lipidomic analyses of LDs isolated from the skeletal muscles of the snake embryos, immunofluorescence, and TEM. Our study also provides a valuable insight concerning the LDs' multifunctionality and ability to interact with a variety of organelles. These LD features are reflected in their proteome composition, which contains scaffold proteins, metabolic enzymes signalling polypeptides, proteins necessary for the formation of docking sites, and many others. We also provide insights into the biogenesis and growth of muscle LDs goes beyond the conventional mechanism based on the synthesis and incorporation of TAGs and LD fusion. We assume that the formation and functioning of grass snake muscle LDs are based on additional mechanisms that have not yet been identified, which could be related to the unique features of reptiles that are manifested in the after-hatching period of life, such as a reptile-specific strategy for energy saving during hibernation.

Melanism, body size, and sex ratio in snakes-new data on the grass snake (Natrix natrix) and synthesis.

It is postulated that melanism in ectotherms is adaptive by enhancing thermoregulation, subsequent resource acquisition, and growth. Such effects may differ between the sexes as a result of the differential costs of self-maintenance and reproduction, but empirical support for the sex-specific consequences of melanism remains inconsistent. We studied the effects of melanism on body size and sex ratio in a population of the European grass snake (Natrix natrix) in SE Poland and also carried out a systematic review of the literature on the consequences of melanism in terrestrial snakes. Melanistic grass snakes of both sexes appeared to be smaller than the typical phenotype, which indicates higher predation pressure and minimal thermal benefits for black individuals. A female-biased sex ratio was observed in the typical phenotype, but not in melanistic snakes, suggesting that the costs for females and/or benefits for males are higher in melanistic individuals. In conjunction with earlier studies, our data indicate that the consequences of melanism may be related to the reproductive mode of species. In viviparous species, melanism tends to improve growth and/or body size and is more frequent in females, whereas the opposite holds for oviparous snakes. Further studies on melanism should examine a wider array of species with different reproductive strategies and traits beyond the usual thermal benefits.

Recent Findings of Potentially Lethal Salamander Fungus Batrachochytrium salamandrivorans.

The distribution of the chytrid fungus Batrachochytrium salamandrivorans continues to expand in Europe. During 2014-2018, we collected 1,135 samples from salamanders and newts in 6 countries in Europe. We identified 5 cases of B. salamandrivorans in a wild population in Spain but none in central Europe or the Balkan Peninsula.

Complete mitochondrial genome of the Eastern slow worm, Anguis colchica (Nordmann, 1840).

Here, we present complete mitochondrial genome of the Eastern Slow Worm, Anguis colchica (Nordmann, 1840). Mitogenome complete sequence is 17,097 bp long and consists of 13 protein-coding genes, 22 tRNA genes, two rRNA genes and one control region. Anguis colchica mitochondrial genome has the same gene order as other mitogenomes of Anguis spp. Their analyzed genome has base composition as: A (30.4%), T (24.6%), C (30.4%), G (14.6%), with an A + T bias (55%). Length of the all 22 tRNA genes varies from 65 to 73 bp with an average of 69 bp. Presented mitogenome will provide new data for phylogenetic analysis within the genus Anguis.

Complete mitochondrial genome of the Italian slow-worm Anguis veronensis Pollini, 1818, and its comparison with mitogenomes of other Anguis species.

In this paper, we present complete mitochondrial genome of the Italian legless lizard species Anguis veronensis Pollini, 1818. The complete mtDNA consisted of 13 protein-coding genes, 22 tRNAs, and two rRNA genes which in total formed a DNA strand of 17,322 bp. Anguis veronensis mitogenome had the same gene order as two other compared Anguis spp., i.e. A. cephallonica and A. fragilis. The base composition of A. veronensis mitochondrial genome was A - 30.8%, T - 24.9%, C - 29.9%, G - 14.4%, with an A + T bias (55.7%). The newly described genome provides valuable data for future comparative mitogenomic analysis within Anguis genus.

Complete mitochondrial genome of the endemic legless lizard Anguis cephallonica Werner, 1894 and its comparison with mitogenome of Anguis fragilis Linnaeus, 1758.

Complete mitochondrial genome of the Peloponnese endemic lizard species Anguis cephallonica is presented in this study. The complete sequence is 17 208 bp long and consists of 13 protein-coding genes, 22 tRNA genes, two rRNA genes and one control region. The gene order is same as in the relative species Anguis fragilis. Length of the 22 tRNA genes varies from 64 bp to 73 bp. The Anguis cephallonica mitogenome base composition is: A (30.5%), T (24.2%), C (30.5%), G (14.8%), with an A + T bias (54.7%). Six protein coding genes have incomplete stop codons. This is the first complete mitogenome described in this species as well as in any endemic Peloponnese lizard. Presented complete mitochondrial genome will form a basis for future comparative analysis within the genus Anguis.