Search

In vivo physiological measurement is a major challenge in modern science and technology, as is environment conservation at the global scale. Proper toxicological testing of widely produced mixtures of chemicals is a necessary step in the development of new products, allowing us to minimize the human impact on aquatic ecosystems. However, currently available bioassay-based techniques utilizing small aquatic organisms such as fish embryos for toxicity testing do not allow assessing in time the changes in physiological parameters in the same individual. In this study, we introduce microencapsulated fluorescent probes as a promising tool for in vivo monitoring of internal pH variation in zebrafish embryos. The pH alteration identified under stress conditions demonstrates the applicability of the microencapsulated fluorescent probes for the repeated analysis of the embryo’s physiological state. The proposed approach has strong potential to simultaneously measure a range of physiological characteristics using a set of specific fluorescent probes and to finally bring toxicological bioassays and related research fields to a new level of effectiveness and sensitivity. [ABSTRACT FROM AUTHOR]

Temperature is the most pervasive abiotic environmental factor for aquatic organisms. Fluctuations in temperature range lead to changes in metabolic performance. Here, we aimed to identify whether surpassing the thermal preference zones is correlated with shifts in universal cellular stress markers of protein integrity, responses to oxidative stress and lactate content, as indicators of anaerobic metabolism. Exposure of the Lake Baikal endemic amphipod species Eulimnogammarus verrucosus (Gerstfeldt, 1858), Ommatogammarus flavus (Dybowski, 1874) and of the Holarctic amphipod Gammarus lacustris Sars 1863 (Amphipoda, Crustacea) to increasing temperatures resulted in elevated heat shock protein 70 (Hsp70) and lactate content, elevated antioxidant enzyme activities (i.e., catalase and peroxidase), and reduced lactate dehydrogenase and glutathione S-transferase activities. Thus, the zone of stability (absence of any significant changes) of the studied molecular and biochemical markers correlated with the behaviorally preferred temperatures. We conclude that the thermal behavioral responses of the studied amphipods are directly related to metabolic processes at the cellular level. Thus, the determined thermal ranges may possibly correspond to the thermal optima. This relationship between species-specific behavioral reactions and stress response metabolism may have significant ecological consequences that result in a thermal zone-specific distribution (i.e., depths, feed spectrum, etc.) of species. As a consequence, by separating species with different temperature preferences, interspecific competition is reduced, which, in turn, increases a species’ Darwinian fitness in its environment. [ABSTRACT FROM AUTHOR]

Actinobacteria isolated from unstudied ecosystems are one of the most interesting and promising sources of novel biologically active compounds. Cave ecosystems are unusual and rarely studied. Here, we report the isolation and characterization of ten new actinobacteria strains isolated from an ancient underground lake and moonmilk speleothem from the biggest conglomeratic karstic cave in Siberia with a focus on the biological activity of the obtained strains and the metabolite dereplication of one active strain. Streptomyces genera isolates from moonmilk speleothem demonstrated antibacterial and antifungal activities. Some of the strains were able to inhibit the growth of pathogenic Candida albicans. [ABSTRACT FROM AUTHOR]

At present, approximately 187 genera and over 1300 species of Microsporidia have been described, among which almost half infect aquatic species and approximately 50 genera potentially infect aquatic arthropods. Lake Baikal is the deepest and one of the oldest lakes in the world, and it has a rich endemic fauna with a predominance of arthropods. Among the arthropods living in this lake, amphipods (Crustacea) are the most dominant group and are represented by more than 350 endemic species. Baikalian amphipods inhabit almost all depths and all types of substrates. The age and geographical isolation of this group creates excellent opportunities for studying the diversity, evolution and genetics of host-parasite relationships. However, despite more than 150 years of study, data investigating the microsporidia of Lake Baikal remain incomplete. In this study, we used molecular genetic analyses to detect microsporidia in the hemolymph of several endemic species of amphipods from Lake Baikal. We provide the first evidence that microsporidian species belonging to three genera (Microsporidium, Dictyocoela and Nosema) are present in the hemolymph of Baikalian endemic amphipods. In the hemolymph of Eulimnogammarus verrucosus, we detected SSU rDNA of microsporidia belonging to the genus Nozema. In the hemolymph of Pallasea cancellous, we found the DNA of Microsporidium sp. similar to that in other Baikalian endemic amphipods; Dictyocoela sp. was found in the hemolymph of Eulimnogammarus marituji and Acanthogammarus lappaceus longispinus. [ABSTRACT FROM AUTHOR]