Bathyal Research Articles

Suppressive might of a few: T follicular regulatory cells impede auto-reactivity despite being outnumbered in the germinal centres.

The selection of high-affinity B cells and the production of high-affinity antibodies are mediated by T follicular helper cells (Tfhs) within germinal centres (GCs). Therein, somatic hypermutation and selection enhance B cell affinity but risk the emergence of self-reactive B cell clones. Despite being outnumbered compared to their helper counterpart, the ablation of T follicular regulatory cells (Tfrs) results in enhanced dissemination of self-reactive antibody-secreting cells (ASCs). The specific mechanisms by which Tfrs exert their regulatory action on self-reactive B cells are largely unknown. We developed computer simulations to investigate how Tfrs regulate either selection or differentiation of B cells to prevent auto-reactivity. We observed that Tfr-induced apoptosis of self-reactive B cells during the selection phase impedes self-reactivity with physiological Tfr numbers, especially when Tfrs can access centrocyte-enriched GC areas. While this aided in selecting non-self-reactive B cells by restraining competition, higher Tfr numbers distracted non-self-reactive B cells from receiving survival signals from Tfhs. Thus, the location and number of Tfrs must be regulated to circumvent such Tfr distraction and avoid disrupting GC evolution. In contrast, when Tfrs regulate differentiation of selected centrocytes by promoting recycling to the dark zone phenotype of self-reactive GC resident pre-plasma cells (GCPCs), higher Tfr numbers were required to impede the circulation of self-reactive ASCs (s-ASCs). On the other hand, Tfr-engagement with GCPCs and subsequent apoptosis of s-ASCs can control self-reactivity with low Tfr numbers, but does not confer selection advantage to non-self-reactive B cells. The simulations predict that to restrict auto-reactivity, natural redemption of self-reactive B cells is insufficient and that Tfrs should increase the mutation probability of self-reactive B cells.

Mesophotic and Bathyal Palaemonid Shrimp Diversity of the Red Sea, with the Establishment of Two New Genera and Two New Species

The diversity and evolution of the Red Sea invertebrates in mesophotic and deep-water benthic ecosystems remain largely unexplored. The Palaemonidae is a diversified family of caridean shrimps with numerous taxa in need of taxonomic revisions based on recent molecular analyses. The Red Sea mesophotic and bathyal palaemonid shrimps are largely unstudied. During recent expeditions off the Red Sea coast of Saudi Arabia, several palaemonid specimens were collected at a depth range of 88–494 m, spanning the mesophotic and bathyal zones. This material was examined morphologically and genetically to infer phylogenetic relationships among the Red Sea taxa and several other palaemonid genera. The concordant morphological and genetic data led to the description of two new genera and two new species. Moreover, one species was recorded in the Red Sea for the first time, with a new host record, whereas three further deep-water species, which do not occur in the Red Sea, were formally transferred to a different genus. As more exploration efforts are deployed, research on the diversity and evolutionary relationships among marine invertebrates from the Red Sea will further underline the uniqueness of its mesophotic and bathyal fauna.

Potential seamount effect on the distribution of the hydrographic features and community structure of pelagic ciliates at the Caroline seamount (tropical western Pacific) in late (2017) and early summer (2019)

Seamounts are ubiquitous features in the world ocean with potential for increasing plankton biodiversity and abundance, and providing important habitats for aquatic predators. Although ecological importance of seamount is well known, the mechanisms for supporting seamount-associated microzooplankton (e.g., pelagic ciliates) communities remains to be substantiated. In this study, pelagic ciliate community structure variations and their relationship with environmental variables were investigated in the Caroline seamount in late (2017) and early summer (2019). Above the seamount in 2019, ciliates exhibited higher abundance and biomass than off the seamount, which supported the classic hypothesis of seamount effect. Aloricate ciliate small size-fraction (10–20 μm) was dominant in bathypelagic (>1000 m) zone. Although relative abundance of small size-fraction was similar in both 2017 and 2019, the absolute abundance in 2019 seamount-effect stations were obviously higher than that in 2017. All abundant tintinnids were classified into surface- and DCM (deep Chl a maximum layer)-peak groups. Among them, four abundant tintinnids (Acanthostomella conicoides, Eutintinnus hasleae, Salpingella curta and S. minutissima) had higher abundance at DCM and might uplifted to shallower waters by upwelling at 2019 seamount-effect stations. The multivariate biota-environment analysis showed that environmental variables have significant impacts on the ciliate community structures in 2017 and 2019. Higher Chl a and nutrient concentrations, and sustained upwelling might be two potential mechanisms for microzooplankton seamount effect. Our study constitutes a rather solid foundation for quantitative and functional study of microzooplankton populations over oligotrophic tropical seamounts.

A new species of Janiralata Menzies, 1951 (Isopoda: Janiridae) from Japanese bathyal waters, with a review of the associations with invertebrates among the species of Janiralata

Abstract Isopods of the genus Janiralata Menzies, 1951 (Asellota: Janiridae) are known from shallow and deep waters of the Northern Hemisphere. Most species are free-living, but some are symbiotic on the surface of other benthic invertebrates. We obtained from three beam- and four otter-trawl hauls 18 Janiralata asellote specimens from the bathyal zone off the Pacific coasts of Tohoku, northeastern Japan. Partial nucleotide sequences of the mitochondrial cytochrome c oxidase subunit I (COI) gene (505 bp) were determined for 16 of the 18 collected specimens. Non-significant genetic differences (< 0.8%) indicated that the individuals were conspecifics. Morphological analysis indicated that all the specimens belonged to a single species, Janiralata planasp. nov. based on the unique morphology of the anterolateral and distolateral projections on the head and pleotelson, surface and lateral margins of the body, antennula article 1, and of the male pleopod 1. Six of the 18 collected specimens were found attached to the surface of an unidentified sea anemone (Hormathiidae), ten to the solasterid starfish Crossaster borealis Fisher, 1906 and two were obtained from the bottom sediment. Three COI haplotypes of the new species were shared by individuals from two neighboring sites, which suggests that genetic isolation occurs on a relatively narrow horizontal scale, although the bathymetric distribution range was rather wide. We describe a case study of the geographic and bathymetric distributions of an asellote species with low dispersal ability and its genetically differentiated populations. Such approach could help elucidate the diversity and distribution of deep-sea organisms and their diversification processes.

NATURAL LIGHTING’S CONTOUR, CASE: CLASSROOM-STUDIO, FLOOR 6th BUILDING C, UNIVERSITAS TRISAKTI

The room requires specific lighting according to its function. One way to achieve the room's optimal comfort is to adjust the natural or artificial lighting to the required standards. This research aims to study daylight intensity in the architectural classroom studio on the sixth floor of Building C Universitas Trisakti and compare it with the illuminance level requirements stipulated in SNI 6197: 2011. This study hypothesizes that the natural intensity of the room, which also functions as an architectural drawing studio, is incompatible with conventional lectures. The measuring instrument was the Lutron LM 8000A Light Lux Meter, while the natural lighting contour simulation used Dialux Evo 9. The results show that the measured natural lighting intensity is unevenly distributed. There are bright zones in the room that exceed the standard value of the illuminance level (> 350-750 lux) and dark zones that are below the standard of illuminance (<350-750 lux), with a distance of 0.5 m - 3m from a row of window openings as a source of lighting.

Pseudotemporal ordering of spatial lymphoid tissue microenvironment profiles trails Unclassified DLBCL at the periphery of the follicle.

We have established a pseudotemporal ordering for the transcriptional signatures of distinct microregions within reactive lymphoid tissues, namely germinal center dark zones (DZ), germinal center light zones (LZ), and peri-follicular areas (Peri). By utilizing this pseudotime trajectory derived from the functional microenvironments of DZ, LZ, and Peri, we have ordered the transcriptomes of Diffuse Large B-cell Lymphoma cases. The apex of the resulting pseudotemporal trajectory, which is characterized by enrichment of molecular programs fronted by TNFR signaling and inhibitory immune checkpoint overexpression, intercepts a discrete peri-follicular biology. This observation is associated with DLBCL cases that are enriched in the Unclassified/type-3 COO category, raising questions about the potential extra-GC microenvironment imprint of this peculiar group of cases. This report offers a thought-provoking perspective on the relationship between transcriptional profiling of functional lymphoid tissue microenvironments and the evolving concept of the cell of origin in Diffuse Large B-cell Lymphomas.

Unveiling the bathypelagic zone with an acoustic vertical profiler

There is a growing interest in the study of mesopelagic and bathypelagic species due to their implication in the active carbon flux and climate change. Underwater acoustics is one of the most efficient methods to study such widely distributed communities. However, there are several challenges among which the reduced spatial resolution with depth for vessel-mounted echosounders stands out. The increase in sampling volume with range precludes observation of fine structures within the scattering layers or the study of less-aggregated organisms far from the transducer face. Echosounders are thus increasingly being deployed in alternative platforms that get the transducer close to the layers of interest. We present here the comparison between two active acoustic platforms used to analyse mesopelagic and bathypelagic species: a vessel-mounted EK60 scientific echosounder and a 6000 m depth rated Acoustic Zooplankton Fish Profiler (AZFP) attached to a CTD rosette. Both systems depicted similar vertical distributions and scattering at 38 kHz for the main scattering layers recorded around the Canary Islands but the finer vertical resolution of the AZFP discerned a series of sub-layers within them that differed in scattering, avoidance and sparsity. The availability of high frequencies at depth also provided further insights on the frequency response of those layers. However, the horizontal orientation of the AZFP created sidelobe artefacts close to the surface and bottom that limit its use in those areas. Signal-to-noise ratio of the AZFP system in the bathypelagic zone also precludes applying echointegration analysis at those depths or outside the denser scattering layers. Finally, the visualization of horizontal or temporal patterns such as migration or mesoscale features is limited to a coarse resolution using data from closely spaced successive stations. New challenges encountered with vertically-deployed echosounders and recommendations for their use are pointed out. Although no scattering layers were detected in the bathypelagic zone, this study unveils an area never before recorded acoustically.

Distribution and clinical impact of molecular subtypes with dark zone signature of DLBCL in a Japanese real-world study

AbstractThe distribution and clinical impact of cell-of-origin (COO) subtypes of diffuse large B-cell lymphoma (DLBCL) outside Western countries remain unknown. Recent literature also suggests that there is an additional COO subtype associated with the germinal center dark zone (DZ) that warrants wider validation to generalize clinical relevance. Here, we assembled a cohort of Japanese patients with untreated DLBCL and determined the refined COO subtypes, which include the DZ signature (DZsig), using the NanoString DLBCL90 assay. To compare the distribution and clinical characteristics of the molecular subtypes, we used a data set from the cohort of British Columbia Cancer (BCC) (n = 804). Through the 1050 patient samples on which DLBCL90 assay was successfully performed in our cohort, 35%, 45%, and 6% of patients were identified to have germinal center B-cell–like (GCB) DLBCL, activated B-cell–like (ABC) DLBCL, and DZsig-positive (DZsigpos) DLBCL, respectively, with the highest prevalence of ABC-DLBCL, differing significantly from the BCC result (P < .001). GCB-DLBCL, ABC-DLBCL, and DZsigpos-DLBCL were associated with 2-year overall survival rates of 88%, 75%, and 66%, respectively (P < .0001), with patients with DZsigpos-DLBCL having the poorest prognosis. In contrast, GCB-DLBCL without DZsig showed excellent outcomes after rituximab-containing immunochemotherapy. DZsigpos-DLBCL was associated with the significant enrichment of tumors with CD10 expression, concurrent MYC/BCL2 expression, and depletion of microenvironmental components (all, P < .05). These results provide evidence of the distinct distribution of clinically relevant molecular subtypes in Japanese DLBCL and that refined COO, as measured by the DLBCL90 assay, is a robust prognostic biomarker that is consistent across geographical areas.

The mammalian midbody and midbody remnant are assembly sites for RNA and localized translation

Long ignored as a vestigial remnant of cytokinesis, the mammalian midbody (MB) is released post-abscission inside large extracellular vesicles called MB remnants (MBRs). Recent evidence suggests that MBRs can modulate cell proliferation and cell fate decisions. Here, we demonstrate that the MB matrix is the site of ribonucleoprotein assembly and is enriched in mRNAs that encode proteins involved in cell fate, oncogenesis, and pluripotency, which we are calling the MB granule. Both MBs and post-abscission MBRs are sites of spatiotemporally regulated translation, which is initiated when nascent daughter cells re-enter G1 and continues after extracellular release. MKLP1 and ARC are necessary for the localization and translation of RNA in the MB dark zone, whereas ESCRT-III is necessary to maintain translation levels in the MB. Our work reveals a unique translation event that occurs during abscission and within a large extracellular vesicle.

Evaluation of the green mussel floating cage related to the enlightenment aspect through the analysis of the Perna viridis spat settlement & population structure

A floating cage is one of the methods of cultivating green mussels that can potentially be used as a medium for maritime education because it is easily accessible to people of various age groups, especially in green mussel cultivation related to mangrove ecotourism. This study aims to analyze the design of floating cages from light and shaded zones based on the spat density and the population structure. The research was conducted in floating cages operated in the Java Sea, Banyuurip Village, Ujungpangkah District at coordinates 06°52’18.84” South Latitude and 112°29’41.19” East Longitude. The spat density was calculated per collector rope per depth (1-4m). When the green mussels were harvested in five-month cultivation from each zone, the population structure was analyzed with Excel 2010 software and measured for the population frequency distribution to investigate the percentage of mussels that reached consumer size. The differences between open and shaded population variables were evaluated by t-test (α=5%). The results of this study show that the density of spat attachment to the collector in the open space was 17.044±724 individuals/m2, and in the shaded area was 16.085±4634 individuals/m2. The density of the spat at a depth of 1m (22,538±4,536 individuals/m2) was significantly different (p<0.05, with three observations) from the density at a depth of 4m (10,830±1,016 individuals/m2) in a light area. However, the spat settlement between each depth was not significantly different in the shaded area. The population structure of green mussels in both areas had seven length classes (class I-VII) with a 7.8 mm interval. The percentage of the class VI population (47.4-55.20 mm) in the light area (31%) was significantly different (p<0.05) from the shaded area (25.79%). It means that the portion of green mussels suitable for harvest (length 40-80 mm) in the light zone is more than in dark zone. We conclude that lighting is an essential aspect of the rate of spat attachment, survival, and growth. The proportion and position of the shaded area in the floating cages must be adjusted so that the growth of the spat is not blocked.

Epstein-Barr virus evades restrictive host chromatin closure by subverting B cell activation and germinal center regulatory loci

Chromatin accessibility fundamentally governs gene expression and biological response programs that can be manipulated by pathogens. Here we capture dynamic chromatin landscapes of individual B cells during Epstein-Barr virus (EBV) infection. EBV+ cells that exhibit arrest via antiviral sensing and proliferation-linked DNA damage experience global accessibility reduction. Proliferative EBV+ cells develop expression-linked architectures and motif accessibility profiles resembling invivo germinal center (GC) phenotypes. Remarkably, EBV elicits dark zone (DZ), light zone (LZ), and post-GC B cell chromatin features despite BCL6 downregulation. Integration of single-cell assay for transposase-accessible chromatin sequencing (scATAC-seq), single-cell RNA sequencing (scRNA-seq), and chromatin immunoprecipitation sequencing (ChIP-seq) data enables genome-wide cis-regulatory predictions implicating EBV nuclear antigens (EBNAs) in phenotype-specific control of GC B cell activation, survival, and immune evasion. Knockouts validate bioinformatically identified regulators (MEF2C and NFE2L2) of EBV-induced GC phenotypes and EBNA-associated loci that regulate gene expression (CD274/PD-L1). These data and methods can inform high-resolution investigations of EBV-host interactions, B cell fates, and virus-mediated lymphomagenesis.

Capparis spinosa Promoted BDNF and Antioxidant Enzyme Levels to Protect Against Learning and Memory Deficits Induced by Scopolamine.

Alzheimer's disease (AD) is a major neurodegenerative disorder with multiple manifestations, including oxidative stress, brain-derived neurotrophic factor (BDNF) depletion, and cholinergic dysfunction. Capparis spinosa (C. spinosa) is identified as a potential source of nutrition for alleviating various ailments. The current study assessed the ameliorating properties of C. spinosa hydroethanolic extract on memory dysfunction and the possible roles of oxidative stress and BDNF in the scopolamine (Scop)-treated rats. Forty male Wistar rats were divided into the following four groups: Control, Scop (2 mg/kg, intraperitoneal injection (i.p.)), Scop + C. spinosa 150, and Scop + C. spinosa 300 groups. The rats were given C. spinosa extract (150 or 300 mg/kg, oral) for 3 weeks. During the third week, Passive Avoidance (PA) and Morris Water Maze (MWM) tests were done to assess memory and learning performance. Finally, oxidative stress markers and BDNF in the brain tissue were evaluated. Scop injection was associated with a significant increase in the time latency and travelled distance to reach the platform during the learning phase of MWM In the probe test, the Scoptreated rats showed a lower time and distance in the target area. Furthermore, Scop injection significantly decreased the latency to enter the dark while increasing the dark time and the frequency of entries to the dark zone of the PA task. C. spinosa extract effectively reversed the behavioural changes induced by Scop. Treatment with the extract also significantly increased the levels of superoxide dismutase, catalase, thiols, and BDNF, while decreasing malondialdehyde production in the brains of the Scop-injured rats. C. spinosa hydroethanolic extract successfully ameliorated Scop-induced memory impairment by modifying BDNF and oxidative stress markers in the brain of amnesic rats.

Acquisition of a glycosylated B-cell receptor drives follicular lymphoma toward a dark zone phenotype

Acquisition of a glycosylated B-cell receptor drives follicular lymphoma toward a dark zone phenotype

Three new species of the family Cirolanidae Dana, 1852 (Isopoda, Cymothoida) from the shallow Brazilian bathyal.

Three new species of isopod crustaceans of the family Cirolanidae-Dolicholana ivanyae spec. nov., Natatolana hadassae spec. nov. and Politolana cleoniceae spec. nov.-are described from the shallow waters of the Brazilian bathyal. The specimens were collected from the shallow bathyal zone of the Potiguar Basin, off the Brazilian state of Rio Grande do Norte, from Pernambuco and Bahia, and the Campos Basin, off Rio de Janeiro and São Paulo states. Dolicholana ivanyae spec. nov. can be distinguished from its congeners by the subrectangular shape of the head, its very long frontal lamina, which surpasses article 2 of the peduncle of antenna 1, and its densely setose pereopod 7. Natatolana hadassae spec. nov. is unique due to the subacute posteroventral angle of epimeron 4, ischial pereopod 3 as produced as those of pereopods 1 and 2, and the distal margin of the pleotelson with 10 robust distal setae. Politolana cleoniceae spec. nov. differs from its congeners based on the combination of the following traits: the pereon-pleon articulation is tight, with pleonite 1 clearly visible, and not covered completely by pereonite 7, while the pleon (in the dorsal-ventral view) is arched in a uniform sequence with the pereon, and the uropodal endopod is shorter than the exopod. In addition to these findings, the known geographical distribution of Dolicholana brucei, which was described recently from Brazil, is extended southward to include Bahia, Brazil. This study increases the number of cirolanid species recorded from Brazilian waters to 23.

IL-21 shapes germinal center polarization via light zone B cell selection and cyclin D3 upregulation.

Germinal center (GC) dysregulation has been widely reported in the context of autoimmunity. Here, we show that interleukin 21 (IL-21), the archetypal follicular helper T cell (Tfh) cytokine, shapes the scale and polarization of spontaneous chronic autoimmune as well as transient immunization-induced GC. We find that IL-21 receptor deficiency results in smaller GC that are profoundly skewed toward a light zone GC B cell phenotype and that IL-21 plays a key role in selection of light zone GC B cells for entry to the dark zone. Light zone skewing has been previously reported in mice lacking the cell cycle regulator cyclin D3. We demonstrate that IL-21 triggers cyclin D3 upregulation in GC B cells, thereby tuning dark zone inertial cell cycling. Lastly, we identify Foxo1 regulation as a link between IL-21 signaling and GC dark zone formation. These findings reveal new biological roles for IL-21 within GC and have implications for autoimmune settings where IL-21 is overproduced.

Black carbon concentrations and modeled smoke deposition fluxes to the bare-ice dark zone of the Greenland Ice Sheet

Abstract. Ice–albedo feedbacks in the ablation region of the Greenland Ice Sheet (GrIS) are difficult to constrain and model due, in part, to our limited understanding of the seasonal evolution of the bare-ice region. To help fill observational gaps, 13 surface samples were collected on the GrIS across the 2014 summer melt season from patches of snow and ice that were visibly light, medium, and dark colored. These samples were analyzed for their refractory black carbon (rBC) concentrations and size distributions with a single-particle soot photometer coupled to a characterized nebulizer. We present a size distribution of rBC in fresh snow on the GrIS and from the weathering crust in the bare-ice dark zone of the GrIS. The size distributions from the weathering crust samples appear unimodal and were overall smaller than the fresh snow sample, with a peak around 0.3 µm. The fresh snow sample contained very large rBC particles that had a pronounced bimodality in the peak size distributions, with peaks around 0.2 and 2 µm. rBC concentrations ranged from a minimum of 3 µg-rBC/L-H2O in light-colored patches at the beginning and end of the melt season to a maximum of 32 µg-rBC/L-H2O in a dark patch in early August. On average, the rBC concentrations were higher (20 ± 10 µg-rBC/L-H2O) in patches that were visibly dark, compared to medium patches (7 ± 2 µg-rBC/L-H2O) and light patches (4 ± 1 µg-rBC/L-H2O), suggesting that BC aggregation contributed to snow aging on the GrIS, and vice versa. Additionally, concentrations peaked in light and dark patches in early August, which is likely due to smoke transport from wildfires in northern Canada and Alaska, as supported by the Navy Aerosol Analysis and Prediction System (NAAPS) reanalysis model. According to the model output, 26 mg m−3 of biomass-burning-derived smoke was deposited between 1 April and 30 August, of which 85 % came from wet deposition, and 67 % was deposited during our sample collection time frame. The increase in the rBC concentration and size distributions immediately after the modeled smoke deposition fluxes suggest that biomass burning smoke is a source of BC to the dark zone of the GrIS. Thus, the role of BC in the seasonal evolution of the ice–albedo feedbacks should continue to be investigated in the weathering crust of the bare-ice zone of the GrIS.

Effect of Machine Pin-Manufacturing Process Parameters by Plasma Nitriding on Microstructure and Hardness of Working Surfaces

This work concerns two stages of research into plasma nitriding (change of nitriding steel and modification of nitriding parameters). In the first stage, pins obtained from currently used steel were compared with pins made of an alternative material available on the market, using the same nitriding process parameters. As a result of the metallographic tests carried out, in the first case, the presence of a thin, porous, and heterogeneous nitrided layer or its absence was found, with the core in its raw state and not thermally improved. In the second case, the presence of a nitrided layer of small thickness with noticeable porosity on the surface of the sample was found, but with a core after heat treatment (incorrect process parameters). Therefore, modification of the parameters of the nitriding process was proposed, in terms of a mixture of gases, currents, time, and temperature of the nitriding process. As a result, a satisfactory effective thickness of the nitrided layer was obtained, consisting of a white near-surface zone with ε and ε + γ′-type nitrides with a thickness of 8.7 to 10.2 µm, and a dark zone of internal nitriding with γ′ nitrides. The nitrides layer was continuous, compact, and well adhered to the steel surface. In the core of the samples, the presence of a fine-needle tempering sorbite structure with a small amount of fine bainite, which is correct for the steel after heat treatment and nitriding, was found. The most favorable parameters of the ion nitriding process were gas flow rate (1.5 L/min N; 0.4 L/min H; 0.3 L/min Ar); currents (BIAS—410 V 4.0 A, SCREEN—320 V 4.0 A); time (26 h and 35 min); and temperature (550 °C).

Age and growth analyses of the purple sea urchin Heliocidaris crassispina inhabiting different feeding environments in the Shimane Peninsula, Japan

The purple sea urchin Heliocidaris crassispina is an echinoid responsible for the denudation of rocky shore seaweed in recent years. We used the gonad index to estimate the spawning period and rotula bones of the mouth to determine the age of H. crassispina individuals living in different feeding environments in the Shimane Peninsula. Seasonal changes in the gonad index suggested that the spawning season for H. crassispina was from May to July, with peak spawning in June. Ring forms in H. crassispina once a year based on the timing of the appearance of the dark zone on the rotula bone; this generally begins around June during the peak spawning period. The age (years) and test diameter (TD, mm) data were fitted to various growth equations. The von Bertalanffy equation that separately used data from the “seaweed bed area” and the “isoyake area” (rocky shore seaweed denudation) resulted in the best fit, with TDt=70.5 (1−e−0.174(t+1.018)) and TDt=60.8 (1−e−0.191(t+1.463)), respectively. This suggested that differences in the feeding environment have a significant effect on the growth of H. crassispina, even in the same bay area. Furthermore, the oldest specimen was estimated to be 25 years old, suggesting that H. crassispina has a higher longevity than that previously reported. Therefore, it is important to manage the H. crassispina population by systematic extermination and not by relying on natural mortality to prevent the decline of seaweed beds.

Ecological-parasitological method in studies of population biology of beaked redfish &lt;i&gt;Sebastes mentella&lt;/i&gt; (Scorpaeniformes: Sebastidae) in the Irminger Sea

The results of the analysis of the data set obtained in course of long-term studies of the population biology of beaked redfish Sebastes mentella are used as an interdisciplinary approach in the study of its geographical, biotopic, ontogenetic and phylogenetic features, population structure in the pelagic zone of the Irminger Sea and the adjacent bathyal zone of Greenland and Iceland. The approach is based on the ecological-parasitological method, which involves the use of data on the composition of parasite communities and the occurrence of their individual species as biomarkers for understanding the features of the hydrobionts ecology. The results obtained, which include information on the spatial distribution, functional subdivision of the area, ontogenetic migrations, maturation and growth rate, underwater marking, phenetic, genetic and other features of beaked redfish, made it possible to identify the conditions for divergent formation and significant isolation of its pelagic and benthic groupings, constituting the North Atlantic population. The colonization by this species of great depths of the oceanic pelagial and the near-bottom layer of the bathyal, accompanied with an increase in the rate of sexual maturation and migratory activity in the pelagial, characterizes the direction of the current stage of its phylogenesis. The unity of the pelagic grouping of beaked redfish in the vast water area and throughout the depth of its distribution in the Irminger and Labrador seas is substantiated. It is shown that significant differences in infestation rate between males and females of beaked redfish, stable in time and space, with the only species-specific parasite (the copepod Sphyrion lumpi), serve as a phene of the pelagic grouping of the North Atlantic population of the host.

Method for identification of &lt;i&gt;acinetobacter baumannii&lt;/i&gt; bv. &lt;i&gt;tryptophandestruens&lt;/i&gt; and its subbiovars A and B

The aim of the study was to increase diagnostic sensitivity for identification of A. baumannii bv. tryptophandestruens bacteria and assess prevalence of this biovar and its subbiovars among A. baumannii clinical isolates. There were examined 210 primary strains of A. baumannii isolated in 20212022 at Bacteriological Laboratory of the Military Medical Academy named after S.M. Kirov, of which 42 strains were A. baumannii bv. tryptophandestruens. Tryptophandestruens biovar bacteria were identified by chromogenic biotransformation of sodium benzoate on a dense nutrient medium (g/l): peptone enzymatic 5.0; NaCl 5.0; FeCl3 6H2O (10% aqueous solution) 0.11 ml; bromothymol blue (1.6% aqueous solution) 3 ml; agar 15.0; NaOH (4% solution) 2.63 ml; distilled water 1 l; all components were dissolved by heating and added with sodium benzoate (CAS 532-32-1) 1.02.0; adjusted pH 7.20.2; sterilized at 121С, poured into Petri dishes. Bacteria of subbiovars A and B of biovar tryptophandestruens were identified by chromogenic biotransformation of L-tryptophan using the same nutrient medium supplemented with L-tryptophan (1.02.0 g/l) instead of sodium benzoate. Both nutrient media were used simultaneously. The A. baumannii cultures studied were seeded with a loop on the media sectors in the form of a plaque, incubated aerobically at 37С for 1824 hours, and analyzed final data as follows: the presence of a dark brown color zone of the nutrient medium around bacterial lawn on sodium benzoate- and L-tryptophan-containing medium indicated detection of subbiovar A of the tryptophandestruens biovar; in case of dark brown zone on sodium benzoate- but not L-tryptophan-containing medium around bacterial lawn identified biovar tryptophandestruens subbiovar B. The study revealed for the first time the chromogenic biotransformation of sodium benzoate (benzoic acid) and its importance as a marker for the biovar tryptophandestruens A. baumannii. Two subbiovars A and B of the tryptophandestruens biovar were found. A method was developed to identify the biovar tryptophandestruens A. baumannii and its subbiovars A and B by chromogenic biotransformation of sodium benzoate and L-tryptophan, which enhances diagnostic sensitivity by detecting the subbiovar B. The frequency of tryptophandestruens biovar distribution among primary clinical isolates of A. baumannii in 20212022 was determined: out of 210 strains of A. baumannii were 42 (20.03.5%) strains of bv. tryptophandestruens including subbiovar A 27 (12.92.3%), subbiovar B 15 (7.11.7%).