Biology subjects

Rinkevich, B.

Publications and source records attributed to Rinkevich, B..

5 recordsLinked to original sources

bioRxiv2025

Two closed systems for long-term propagation of the marine tunicate Botryllus schlosseri isolated from natural seawater

Advanced methodologies for Botryllus schlosseri artificial seawater systems are needed to decrease dependency of large-scale culture on natural seawater and expand use of this important new model organism to more inland laboratories. We constructed two botryllid tunicate customized closed aquaculture systems, a static system consisting of lightly aerated jars fed with commercial filter feeder diet, and a recirculating aquaculture system (RAS) consisting of standard marine RAS components fed live microalgae and zooplankton diets. Initially, static tunicate culture yielded exponential growth in contrast to the RAS system, which yielded poor survival and negligible growth. Modifications were made to the RAS system to improve water treatment proficiency that greatly improved tunicate survival and growth. Experiments were performed isolating feed and water type as variables that differed between the static and RAS systems to evaluate their effects. A live feed combination achieved five-fold greater growth relative to a commercial concentrate diet. B. schlosseri maintained in optimized RAS water achieved two-fold faster growth relative to animals maintained with freshly prepared artificial seawater indicating that the RAS water was beneficial to the animals. Feeding frequency of the RAS system was increased from three times per week to daily. The RAS system and procedural modifications resulted in comparable growth rates in the static and RAS systems. Both optimized systems are suitable for long-term propagation and sustenance of botryllid tunicate populations supporting both sexual and asexual modes of reproduction with a current residence time of over 24 months.

zoology↗

bioRxiv2024

Proteome-wide 4-hydroxy-2-nonenal signature of oxidative stress in the marine invasive tunicate Botryllus schlosseri

The colonial ascidian Boytryllus schlosseri is an invasive marine chordate that thrives under conditions of anthropogenic climate change. We show that the B. schlosseri expressed proteome contains unusually high levels of proteins that are adducted with 4-hydroxy-2-nonenal (HNE). HNE represents a prominent posttranslational modification resulting from oxidative stress. Although numerous studies have assessed oxidative stress in marine organisms HNE protein modification has not previously been determined in any marine species. LC/MS proteomics was used to identify 1052 HNE adducted proteins in B. schlosseri field and laboratory populations. Adducted amino acid residues were ascertained for 1849 modified sites, of which 1195 had a maximum amino acid localization score. Most HNE modifications were at less reactive lysines (rather than more reactive cysteines). HNE prevelance on most sites was high. These observations suggest that B. schlosseri experiences and tolerates high intracellular reactive oxygen species levels, resulting in substantial lipid peroxidation. HNE adducted B. schlosseri proteins show enrichment in mitochondrial, proteostasis, and cytoskeletal functions. Based on these results we propose that redox signaling contributes to regulating energy metabolism, the blastogenic cycle, oxidative burst defenses, and cytoskeleton dynamics during B. schlosseri development and physiology. A DIA assay library was constructed to quantify HNE adduction at 72 sites across 60 proteins that represent a holistic network of functionally discernable oxidative stress bioindicators. We conclude that the vast amount of HNE protein adduction in this circumpolar tunicate is indicative of high oxidative stress tolerance contributing to its range expansion into diverse environments. NEW & NOTEWORTHYOxidative stress results from environmental challenges that increase in frequency and severity during the Anthropocene. Oxygen radical attack causes lipid peroxidation leading to HNE production. Proteome-wide HNE adduction is highly prevalent in Botryllus schlosseri, a widely distributed, highly invasive, and economically important biofouling ascidian and the first marine species to be analyzed for proteome HNE modification. HNE adduction of specific proteins physiologically sequesters reactive oxygen species, which enhances fitness and resilience during environmental change.

systems biology↗

bioRxiv2023

The Orshina rhythm in a colonial urochordate: recurrent aging/rejuvenation sequels

When it comes to aging, some colonial invertebrates present disparate patterns from the customary aging phenomenon in unitary organisms, where a single senescence phenomenon along ontogeny culminates in their inevitable deaths. Here we studied aging processes in 81 colonies of the marine urochordate Botryllus schlosseri each followed from birth to death (over 720 days). The colonies were divided between three life history strategies, each distinct from the others based on the existence/absence of colonial fission: NF (no fission), FA (fission develops after the colony reaches maximal size), and FB (fission develops before the colony reaches maximal size). Results revealed that sexual reproductive statuses (hermaphroditism and male only settings), colonial vigorousness and sizes, represent coinciding and repeated rhythms of one or more emerged life/death astogenic segments on the whole-genet level, each is termed as Orshina, and the sum of all segments as the Orshina rhythm. Each Orshina segment lasts about three months (containing ca. 13 blastogenic cycles), ends by either the colonial death or rejuvenation, and manipulated by absence/existing of fission events in NF/FA/FB strategies. These findings indicate that reproduction, life span, death, rejuvenation and fission events are important scheduled biological components in the constructed Orshina rhythm, a novel aging phenomenon.

evolutionary biology↗

bioRxiv2023

Species delimitation of eight ascidian (Tunicata) species from the North Eastern Mediterranean

Members of the tunicates, a subphylum of marine filter-feeder chordates, inhabit all marine and oceanic habitats from the subtidal to the abyssal. Considered as the closest relatives to the vertebrates, the tunicates are widely used as model organisms for evo-devo, allorecognition, senescence, and whole-body regeneration studies. Yet, species boundaries are poorly understood due to high morphological and genetic plasticity that characterize many tunicates taxa. Here we study taxonomy and the distribution of eight tunicate species (Botrylloides niger Herdman, 1886/ aff. leachii, Botrylloides israeliense Brunetti, 2009, Botrylloides sp., Botrylloides anceps (Herdman, 1891), Botryllus schlosseri (Pallas, 1766), Didemnum perlucidum Monniot F., 1983, Symplegma brakenhielmi (Michaelsen, 1904) and Polyclinum constellatum Savigny, 1816) sampled from six Turkish North Eastern Mediterranean Sea sites and employed the mitochondrial barcoding marker (COI) for evaluating the relationships among geographically restricted and widely spread ascidian species. Species delimitation analysis was conducted using NCBI and the present study sequences. Morphological examinations were first done in the field and then, styelide colonies were cultured in the laboratory and studied using stereo and light microscopes. A putative new Botrylloides species (Botrylloides sp.) from the Antalya region was revealed, with 99% matching on the COI gene from Saudi Arabia, further awaiting for detailed traditional taxonomy.

genetics↗

bioRxiv2019

DNA barcode reference libraries for the monitoring of aquatic biota in Europe: Gap-analysis and recommendations for future work

Effective identification of species using short DNA fragments (DNA barcoding and DNA metabarcoding) requires reliable sequence reference libraries of known taxa. Both taxonomically comprehensive coverage and content quality are important for sufficient accuracy. For aquatic ecosystems in Europe, reliable barcode reference libraries are particularly important if molecular identification tools are to be implemented in biomonitoring and reports in the context of the EU Water Framework Directive (WFD) and the Marine Strategy Framework Directive (MSFD). We analysed gaps in the two most important reference databases, Barcode of Life Data Systems (BOLD) and NCBI GenBank, with a focus on the taxa most frequently used in WFD and MSFD. Our analyses show that coverage varies strongly among taxonomic groups, and among geographic regions. In general, groups that were actively targeted in barcode projects (e.g. fish, true bugs, caddisflies and vascular plants) are well represented in the barcode libraries, while others have fewer records (e.g. marine molluscs, ascidians, and freshwater diatoms). We also found that species monitored in several countries often are represented by barcodes in reference libraries, while species monitored in a single country frequently lack sequence records. A large proportion of species (up to 50%) in several taxonomic groups are only represented by private data in BOLD. Our results have implications for the future strategy to fill existing gaps in barcode libraries, especially if DNA metabarcoding is to be used in the monitoring of European aquatic biota under the WFD and MSFD. For example, missing species relevant to monitoring in multiple countries should be prioritized. We also discuss why a strategy for quality control and quality assurance of barcode reference libraries is needed and recommend future steps to ensure full utilization of metabarcoding in aquatic biomonitoring.

ecology↗