Molecular and morphological screening of Podocotyle spp. (Trematoda: Opecoelidae) sheds light on their diversity in Northwest Pacific and eastern European Arctic

Podocotyle is a genus of marine opecoelid digeneans that parasitize a wide variety of fish as adults. We present the first phylogenetic analysis of several Podocotyle isolates using nuclear 28S rDNA and mitochondrial cox1 DNA regions. New sequences were obtained for Podocotyle specimens from fish caught in the Sea of Okhotsk and the White Sea. Based on morphological and molecular data, eight Podocotyle lineages of species rank were revealed. However, this diversity is poorly formalized within the current taxonomic model of the genus. As a result, we identified Podocotyle cf. angulata, Podocotyle cf. atomon, Podocotyle cf. reflexa, Podocotyle atomon of Sokolov et al., 2019, Podocotyle sp. of Denisova et al., 2023, Podocotyle sp. 1, Podocotyle sp. 2 and Podocotyle sp. 3. We also highlight the unresolved question of the life cycles of representatives of Podocotyle whose intramolluscan stages parasitize the intertidal snails Littorina spp.

Security labeling and optical information encryption enabled by laser-printed silicon Mie resonators

Fighting against the falsification of valuable items remains a crucial social-threatening challenge stimulating a never-ending search for novel anti-counterfeiting strategies. The demanding security labels must simultaneously address multiple requirements (high density of the recorded information, high protection degree, etc.) and be realized via scalable and inexpensive technologies. Here, the direct reproducible femtosecond-laser patterning of thin glass-supported amorphous (α-)Si films is proposed for optical information encryption and the scalable and highly reproducible fabrication of security labels composed of Raman-active hemispherical Si nanoparticles (NPs). Laser printing conditions allow the precise control of the diameter of the formed NPs ensuring translation of their dipolar Mie resonance position within the entire visible spectral range. Two-temperature molecular dynamics simulations clarify the origin of α-Si NP formation by rupture of the molten Si layer driven by a negative GPa-range pressure near the liquid-solid interface. Arrangement of the laser-printed Mie-resonant NP allows the creation of hidden security labels offering several easy-to-realize information encryption strategies (for example, local laser-induced post-crystallization or mixing Mie-resonant and non-resonant NPs), additional protection modalities, facile Raman mapping readout and dense information recording (up to 60 000 dots per inch) close to the optical diffraction limit. The developed fabrication strategy is simple, inexpensive, and scalable and can be realized based on cheap Earth-abundant materials and commercially-available equipment justifying its practical applicability and attractiveness for anti-counterfeit and security applications.

The first report of a parasitic 'turbellarian' from a cephalopod mollusc, with description of Octopoxenus antarcticus gen. nov., sp. nov. (Platyhelminthes: Fecampiida: Notenteridae)

Parasitic 'turbellarians' are known from various animals such as echinoderms, crustaceans, annelids, bivalve and gastropod molluscs. So far, however, no 'turbellarians' have been reported from cephalopods. In this paper we report a parasitic 'turbellarian' from the giant Antarctic octopus, Megaleledone setebos. We dissected two specimens of M. setebos caught in the Ross Sea (Antarctica) and found numerous worms in their intestine and liver. The worms were spherical or oblong and had two morphologically different poles. The frontal pole bears a small conical protrusion containing large elongated pear-shaped frontal glands and large polygonal cells. The ducts of the frontal glands open terminally to form the frontal organ. The caudal pole has an opening shaped as a folded tube connected by the genital pore with a common genital atrium, which continues into a canal with a muscular sheath. The worms were identified as 'turbellarians' from the family Notenteridae (Fecampiida). This family contains only one species, Notentera ivanovi, reported from the gut of a polychaete at the White Sea. The worms that we found in the gastrointestinal tract of the octopuses were morphologically similar to N. ivanovi but differed from it in several important respects. Phylogenetic analysis based on 28S rDNA gene showed that the newly found worm clustered together with other fecampiids in a highly supported clade and was closely related to N. ivanovi. On the basis of these morphological and molecular data, we described a new species, Octopoxenus antarcticus gen. nov., sp. nov. (Fecampiida: Notenteridae), establishing a new genus to accommodate it and provided an updated diagnosis of the family Notenteridae. This is the first report of a parasitic 'turbellarian' from a cephalopod mollusc.

POS1214 THE DYNAMICS OF INFLAMMATORY MARKERS IN COVID-19 PATIENTS TREATED WITH LEVILIMAB

Background:

Levilimab (LVL) is a novel anti-IL6Rmonoclonal antibody against IL6Rα. Cytokine release syndrome plays the key role in the pathogenesis of a range of life-threatening conditions including the acute respiratory distress syndrome in severely ill COVID-19 patients. Thus, the use of LVL could be considered as anti-cytokine therapy with a potency to prevent the complications and progression of respiratory failure in COVID-19.

Objectives:

We analyzed the changes in the serum concentrations of inflammatory markers (Erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and IL-6) in patients treated with LVL or placebo as part of a phase III multicenter randomized double-blind placebo-controlled adaptive-design CORONA clinical study aimed to evaluate the efficacy and safety of LVL in subjects with severe COVID-19 (NCT04397562).

Methods:

A total of 217 patients were enrolled in the study, 206 patients were randomized, and 204 patients received the investigational product (IP, LVL or placebo).

Study included men and non-pregnant women aged ≥18 years, hospitalized for severe COVID-19 pneumonia, receiving standard therapy according to the national guidelines. Patients with acute respiratory failure with the need in invasive respiratory support, septic shock, multiple organ failure or life expectancy less than 24 hours could not participate in the study. The use of other monoclonal antibodies and glucocorticoids for the treatment of COVID-19 were not allowed.

Subjects were stratified according to the CRP level (CRP ≤ 7 mg/L; CRP > 7 mg/L) and then randomized (1:1) into 2 groups to receive LVL 324 mg or placebo. LVL/placebo were administered as a single subcutaneous injection, investigator and patients were unaware of the received therapy.

Among secondary endpoints of the study changes from baseline in ESR, CRP and IL-6 concentrations were assessed. CRP level and ESR were measured before the IP administration and on Days 3, 5, 7, 14, 21, 29 and 30. Blood samples for the measurement of IL-6 concentration were obtained before the IP administration and then every day for 2 weeks after administration.

Results:

We observed the pronounced decrease of ESR in LVL group compared to Placebo group. The difference was statistically significant on Days 3 and 7: the median ESR change from baseline was -3 mm/h and +3 mm/h on Day 3, -11 mm/h and -3.1 mm/h on Day 7, in LVL and Placebo groups, respectively (p=0.0319 and p=0.0110, Days 3 and 7). The statistically significant difference in the change of CRP level was detected between the groups on Day 3: -26.6±41.9 mg/L and -19.2±58.2 mg/L in LVL and Placebo groups, respectively (p=0.0241). Numerically the same dynamics of ESR and CRP was observed over entire study period.

The dynamics of IL-6 serum concentrations in LVL and Placebo groups was strikingly different. After LVL administration we detected the rapid significant increase in IL-6 concentration due to IL-6 receptors inhibition. Maximum change from baseline was observed on Day 3 (+91.9±117.7 pg/mL), on Day 14 the value was +31.9±62.7 pg/mL.

In the Placebo group, the IL-6 concentration increased slightly until Day 4 (+5,1±76,5 pg/mL), and then decreased significantly (-39.2±55.1 pg/mL on Day 14) due to clinical improvement in this group.

Conclusion:

The significant differences in the dynamics of ESR, CRP and IL-6 after LVL administration compared to placebo confirmed the pharmacodynamic effect and its potency to prevent the excessive release of inflammatory substances in severely ill COVID-19 patients.

References:

[1]Xu X, Han M, Li T, Sun W, Wang D, Fu B, Zhou Y, Zheng X, Yang Y, Li X, Zhang X, Pan A, Wei H. Effective treatment of severe COVID-19 patients with tocilizumab. Proc Natl Acad Sci U S A. 2020 May 19;117(20):10970-10975. doi: 10.1073/pnas.2005615117. Epub 2020 Apr 29. PMID: 32350134; PMCID: PMC7245089.

Acknowledgements:

We thank all contributors to the CORONA study.

Disclosure of Interests:

Nikita Lomakin: None declared, Bulat Bakirov: None declared, Gaziiavdibir Musaev: None declared, Denis Protsenko: None declared, Olga Moiseeva: None declared, Elena Pasechnik: None declared, Vladimir Popov: None declared, Elena Smolyarchuk: None declared, Ivan Gordeev: None declared, Michail Gilyarov: None declared, Daria Fomina: None declared, V Mazurov: None declared, Maria Morozova Employee of: JSC BIOCAD, Ekaterina Dokukina Employee of: JSC BIOCAD, Dmitrii Bogdan Employee of: JSC BIOCAD, Anton Lutskii Employee of: JSC BIOCAD, Arina Zinkina-Orihan Employee of: JSC BIOCAD, Iulia Linkova Employee of: JSC BIOCAD, Anton Seleznev Employee of: JSC BIOCAD.

Description of a metacercaria of a zoogonid trematode Steganoderma cf. eamiqtrema Blend and Racz, 2020 (Microphalloidea: Zoogonidae), with notes on the phylogenetic position of the genus Steganoderma Stafford, 1904, and resurrection of the subfamily Lecithostaphylinae Odhner, 1911

Metacercariae of the zoogonid trematode Steganoderma cf. eamiqtrema ex crab Chionoecetes bairdi caught in the Sea of Okhotsk were described using morphological and molecular-genetic (ITS2 region, 28S rRNA and nd1 genes) data. These are the first molecular-genetic data for the genus Steganoderma. The studied trematodes differed from S. eamiqtrema in having a much larger body size. The phylogenetic analysis based on the 28S rRNA gene supported neither the current taxonomic hypothesis that Steganoderma belongs to the subfamily Lepidophyllinae nor the earlier views that the Steganodermatinae and the Lecithostaphylinae are synonymous. The topology of the phylogenetic tree shows that the Steganodermatinae and the Lecithostaphylinae are independent subfamilies. However, morphological differences between them are obscure. Until morphological evidence for the Steganodermatinae is found, we propose to distinguish the subfamily Lepidophyllinae sensu stricto with the genera Lepidophyllus and Urinatrema, and the subfamily Lecithostaphylinae sensu lato uniting all the other former lepidophyllines. Thus, for now, we propose to consider the Steganodermatinae as a conditional synonym for Lecithostaphylinae sensu lato.

Surface Study of Fe3O4 Nanoparticles Functionalized With Biocompatible Adsorbed Molecules

Surfaces of iron oxide of ferrimagnetic magnetite (Fe₃O₄) nanoparticles (MNPs) prepared by Massart's method and their functionalized form (f-MNPs) with succinic acid, L-arginine, oxalic acid, citric acid, and glutamic acid were studied by dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR-S), UV-vis, thermogravimetric analysis (TGA)/differential scanning calorimetry (DSC), X-ray photoelectron spectroscopy (XPS), and reflection electron energy loss spectroscopy (REELS). The XPS analysis of elements and their chemical states at the surface of MNPs and f-MNPs revealed differences in chemical bonding of atoms, content of carbon–oxygen groups, iron oxide forms, iron oxide magnetic properties, adsorbed molecules, surface coverage, and overlayer thickness, whereas the Auger parameters (derived from XPS and Auger spectra) and elastic and inelastic scattering probabilities of electrons on atoms and valence band electrons (derived from REELS spectra) indicated modification of surface charge redistribution, electronic, and optical properties. These modified properties of f-MNPs influenced their biological properties. The surfaces biocompatible for L929 cells showed various cytotoxicity for HeLa cells (10.8–5.3% of cell death), the highest for MNPs functionalized with oxalic acid. The samples exhibiting the largest efficiency possessed smaller surface coverage and thickness of adsorbed molecules layers, the highest content of oxygen and carbon–oxygen functionalizing groups, the highest ratio of lattice O²⁻ and OH⁻ to C sp² hybridizations on MNP surface, the highest ratio of adsorbed O⁻ and OH⁻ to C sp² hybridizations on adsorbed molecule layers, the closest electronic and optical properties to Fe₃O₄, and the lowest degree of admolecule polymerization. This high cytotoxicity was attributed to interaction of cells with a surface, where increased content of oxygen groups, adsorbed O⁻, and OH⁻ may play the role of additional adsorption and catalytic sites and a large content of adsorbed molecule layers of carboxylic groups facilitating Fenton reaction kinetics leading to cell damage.

RMS roughness-independent tuning of surface wettability by tailoring silver nanoparticles with a fluorocarbon plasma polymer

A layer of 14 nm-sized Ag nanoparticles undergoes complex transformation when overcoated by thin films of a fluorocarbon plasma polymer. Two regimes of surface evolution are identified, both with invariable RMS roughness. In the early regime, the plasma polymer penetrates between and beneath the nanoparticles, raising them above the substrate and maintaining the multivalued character of the surface roughness. The growth (β) and the dynamic (1/z) exponents are close to zero and the interface bears the features of self-affinity. The presence of inter-particle voids leads to heterogeneous wetting with an apparent water contact angle θ_a = 135°. The multivalued nanotopography results in two possible positions for the water droplet meniscus, yet strong water adhesion indicates that the meniscus is located at the lower part of the spherical nanofeatures. In the late regime, the inter-particle voids become filled and the interface acquires a single valued character. The plasma polymer proceeds to grow on the thus-roughened surface whereas the nanoparticles keep emerging away from the substrate. The RMS roughness remains invariable and lateral correlations propagate with 1/z = 0.27. The surface features multiaffinity which is given by different evolution of length scales associated with the nanoparticles and with the plasma polymer. The wettability turns to the homogeneous wetting state.

Redescription of Proctophantastes gillissi (Overstreet et Pritchard, 1977) (Trematoda: Zoogonidae) with discussion on the systematic position of the genus Proctophantastes Odhner, 1911

The redescription of Proctophantastes gillissi (Overstreet et Pritchard, 1977) (Trematoda: Zoogonidae) was made on specimens collected from Muraenolepis marmorata Günther, 1880 (Gadiformes) caught in the Ross Sea and the Amundsen Sea (Antarctic). The fish is a new host of this parasite. Phylogenetic relations of P. gillissi were inferred by Maximum Likelihood and Bayesian inference analysis of partial sequences from 28S rDNA. The findings from analysis of the molecular data are not consistent with the traditional point of view about the position of the genus Proctophantastes Odhner, 1911 in the subfamily Lepidophyllinae. The taxonomical position of the genus needs further revision.

New tentacled leech Ceratobdella quadricornuta n. g., n. sp. (Hirudinida: Piscicolidae) parasitic on the starry skate Raja georgiana Norman from the Scotia Sea, Antarctica

A new fish leech Ceratobdella quadricornuta n. g., n. sp. (Hirudinida: Piscicolidae), a parasite of the Antarctic skate Raja georgiana Norman (Rajiformes: Rajidae) collected between the Falkland Islands and South Georgia Island in the Scotia Sea, is described and compared with related genera. Ceratobdella quadricornuta is characterised by an uncommon appearance of its anterior sucker bearing four well-developed tentacles and a unique combination of features of the reproductive and digestive systems: crop and intestine equally developed, posterior crop caeca separated; accessory glands, conductive tissue and external copulatory area lacking; common part of ejaculatory ducts (common atrium) voluminous and muscular, male copulatory bursa short, small ovisacs opening into female copulatory bursa (vagina).