Algal and cyanobacterial diversity in saline rivers of the Elton Lake Basin (Russia) studied via light microscopy and next-generation sequencing

Naturally saline rivers are known in various regions of the world. Saline rivers with a salinity gradient from the source to the mouth are particularly interesting, because the range of salinity is the structure-forming factor of the hydrobiont assemblage. Such rivers are represented by saline rivers of the Elton Lake Basin in Volgograd region of Russia (the Bolshaya Samoroda River and the Malaya Samoroda River). Herein, we analyzed taxonomic structure and species diversity of microalgae and Cyanobacteria of the saline rivers flowing into the Elton Lake by light microscopy and next-generation sequencing. The differences and possible causes of inconsistencies in the results obtained by these methods are discussed. In total, 91 taxa of microorganisms were identified by integrated approach in the assemblages of microalgae and Cyanobacteria in the middle course of the Bolshaya Samoroda River, and 60 taxa – in the river mouth. The species diversity of those assemblages in the hypersaline Malaya Samoroda River was lower: 27 taxa from the middle course and 23 taxa from the mouth. Next-generation sequencing allowed us to refine and expand the list of microalgae taxa in the studied saline rivers due to detection of species which were hard to identify, low-abundance taxa, as well as extremely small-cell forms. Some discrepancies between the data obtained by light microscopy and next-generation sequencing indicate the advantage of simultaneous use of both methods for study of the algae communities. Such a comprehensive approach provides the most accurate and correct list of taxa added with the morphological descriptions and 18S rRNA and 16S rRNA partial sequences. Generally, 18 taxa have been recorded for the first time in the Bolshaya Samoroda River, belonging to the phyla Chlorophyta (Borodinellopsis sp., Chlorochytrium lemnae Cohn, Caespitella sp., Halochlorococcum sp., Tetraselmis cordiformis (H. J. Carter) F. Stein), Ochrophyta (Pseudocharaciopsis ovalis (Chodat) D. J. Hibberd, Characiopsis sp., Poterioochromonas stipitata Scherffel, Chrysolepidomonas sp.), Euglenozoa (Euglena bucharica I. Kisselev, Lepocinclis tripteris (Dujardin) B. Marin & Melkonian, Phacus orbicularis K. Hübner, P. parvulus G. A. Klebs), Cryptophyta (Hemiselmis cryptochromatica C. E. Lane & J. M. Archibald, Rhodomonas sp., Hanusia phi J. A. Deane), Haptophyta (Pavlova sp.), Cyanobacteria (Johanseninema constrictum (Szafer) Hasler, Dvorák & Poulícková). Seven taxa have been detected for the first time in the algal and cyanobacterial assemblages of the Malaya Samoroda River from the phyla Chlorophyta (Tetraselmis cordiformis, T. arnoldii (Proschkina-Lavrenko) R. E. Norris, Hori & Chihara, T. tetrathele (West) Butcher, Pyrobotrys elongatus Korshikov), Cryptophyta (Hanusia phi), and Cyanobacteria (Synechococcus elongatus (Nägeli) Nägeli, Oscillatoria simplicissima Gomont)

Diversity of Prokaryotes in Planktonic Communities of Saline Sol-Iletsk lakes (Orenburg Oblast, Russia)

© 2018, Pleiades Publishing, Ltd. Prokaryotic diversity was studied in the planktonic communities of six Sol-Iletsk lakes (Orenburg oblast, Russia) varying in salinity level using the Illumina technology of high-throughput sequencing. The extremely halophilic archaea of the phyla Euryarchaeota and Nanohaloarchaeota, as well as the bacterial phylum Bacteroidetes predominated in the communities of lakes with salinity of 285–300‰. Representatives of the phyla Bacteroidetes and Actinobacteria, as well as of the class Gammaproteobacteria were predominant in the lakes with salinity 110−180‰. A bloom of Cyanobacteria was observed in Bol’shoe Gorodskoe Lake (10‰ salinity). The dominant OTUs in the lakes with high salinity were represented by archaea Halonotius sp., uncultured Nanohaloarchaea, and bacteria Salinibacter sp. In the lakes with medium salinity level the dominants included gammaproteobacteria Spiribacter sp., alphaproteobacteria Roseovarius sp., flavobacteria Psychroflexus sp., unidentified archaea of the family Haloferacaceae, actinobacteria Pontimonas sp. and Rhodoluna sp. In the lake with low salinity level cyanobacteria of the genus Planktothrix were predominant. Effect of salinity on prokaryotic taxonomic richness, composition, and diversity in planktonic communities of the studied lakes was demonstrated

Nanohaloarchaea as beneficiaries of xylan degradation by haloarchaea

Climate change, desertification, salinisation of soils and the changing hydrology of the Earth are creating or modifying microbial habitats at all scales including the oceans, saline groundwaters and brine lakes. In environments that are saline or hypersaline, the biodegradation of recalcitrant plant and animal polysaccharides can be inhibited by salt-induced microbial stress and/or by limitation of the metabolic capabilities of halophilic microbes. We recently demonstrated that the chitinolytic haloarchaeon Halomicrobium can serve as the host for an ectosymbiont, nanohaloarchaeon ‘Candidatus Nanohalobium constans’. Here, we consider whether nanohaloarchaea can benefit from the haloarchaea-mediated degradation of xylan, a major hemicellulose component of wood. Using samples of natural evaporitic brines and anthropogenic solar salterns, we describe genome-inferred trophic relations in two extremely halophilic xylan-degrading three-member consortia. We succeeded in genome assembly and closure for all members of both xylan-degrading cultures and elucidated the respective food chains within these consortia. We provide evidence that ectosymbiontic nanohaloarchaea is an active ecophysiological component of extremely halophilic xylan-degrading communities (although by proxy) in hypersaline environments. In each consortium, nanohaloarchaea occur as ectosymbionts of Haloferax, which in turn act as scavenger of oligosaccharides produced by xylan-hydrolysing Halorhabdus. We further obtained and characterised the nanohaloarchaea–host associations using microscopy, multi-omics and cultivation approaches. The current study also doubled culturable nanohaloarchaeal symbionts and demonstrated that these enigmatic nano-sized archaea can be readily isolated in binary co-cultures using an appropriate enrichment strategy. We discuss the implications of xylan degradation by halophiles in biotechnology and for the United Nation's Sustainable Development Goals

Hemodynamics at different levels of salt intake in patients with hypertrophic cardiomyopathy of different age groups

Aim. To assess the relationship between the level of salt (NaCl) consumption and clinical and hemodynamic parameters in patients with hypertrophic cardiomyopathy (HCM) of different age groups.Material and methods. We examined 57 patients with HCM (mean age, 59,2±16,2 years). The patients were divided into groups according to the World Health Organization (WHO): I — young age (≤44 years old) — 12,4% of patients; II — middle (45-59 years old) — 37,2%; III — elderly (60–74 years old) — 36%; IV — senile (≥75 years old old) — 14,4%. The clinical status of patients was assessed, during which special attention was paid to syncope not related to cardiac arrhythmias. NaCl intake was assessed by the 24-hour urine sodium (Na+) level.Results. In the general cohort, in Na+ level <50 mmol/day, the lowest left ventricular stroke volume (LVSV) index was observed, which were associated with syncope (r=-0,9, p=0,03). With the urinary sodium level of 50-70 mmol/day, an increase in LVSV index was observed and the absence of syncope. At Na+ level more than 70 mmol/day, no increase in LVSV index was observed. In this regard, a predictive model was created, as a result of which it was found that with an increase in Na+ consumption by 1 mmol/day, an increase in LVSV index by 0,3 ml/m2 should be expected. There were no significant differences in the effect of NaCl intake on the studied parameters in patients with HCM of different ages. At the same time, low NaCl intake in elderly patients was associated with syncope.Conclusion. Minimal values of Na+ intake (<50 mmol/day or NaCl 3 g/day) were found, which are unfavorable for patients with HCM due to the risk syncope. The 24-hour urine sodium level to maintain a hemodynamically safe level of LVSV index in patients with HCM should be more than 70 mmol/day (NaCl 4,1 g/day). Monitoring of Na+ consumption level is especially important in elderly people with HCM

Novel membrane mimetic systems based on amphiphilic oxyethylated calix[4]arene: Aggregative and liquid crystalline behavior

Self-organization of amphiphilic calixarenes oxyethylated at a lower rim has been investigated in water and water-organic solutions. In the range of isotropic solutions three types of structural transitions were indicated by a complex of methods. The first critical point indicated by surface tension, dynamic light scattering and atomic force microscopy methods is probably connected with the formation of " infinite" organized structures (of hundreds nanometers in size) through the open association model. This aggregative phenomenon covers the concentration range below 10-3M. In the case of aqueous calixarene solutions these large aggregates co-exist with small micelle-like particles and undergo a rearrangement with an increase in the concentration. The second structural transition occurs beyond 10-3M. It is revealed in aqueous calixarene solutions by surface tension, spine probe, viscosimetry and dynamic light scattering methods. Small aggregates (~10nm in diameter) are formed in this range through a closed model typical for conventional surfactants. The third transition indicated by viscosimetry and in single case by tensiometry can be connected with an elongation of aggregates. The polarization microscopy and X-ray diffraction studies reveal the anisotropic behavior with the concentration of solutions. Parameters of the existence of liquid crystalline mesophases are found to be influenced by the structure of substituents at both the upper and lower rims, as well as by the nature of solvent. © 2010 Elsevier B.V

The Case of Langerhans Cell Histiocytosis (Abt-Letterer-Siwe Disease) in Twin Girls

Abt-Letterer-Siwe disease is a form of Langerhans cell histiocytosis and occurs in 2–10 cases per 1 million of the child population per year. The Russian and foreign literature provide descriptions of this disease in children of different ages. Family cases of this pathology are described in a small number. The chapter presents a rare clinical observation of the Abt-Letterer-Siwe disease in twin girls

THE KINETICS OF AUSTENITE FORMATION IN THE STEEL 08Г2Б WITH DIFFERENT INITIAL STRUCTURE

Samples of low-carbon pipe steel 08G2B after control rolling, normalization and quenching were investigated. The kinetics of the austenite formation under conditions of continuous heating with rate 90 оС/с and during isothermal soaking in the inter-critical temperature range were analyzed. The critical points Ac1 and Ac3, the activation energy of the austenite formation have been determined.В работе исследованы образцы низкоуглеродистой трубной стали 08Г2Б после контролируемой прокатки, нормализации и закалки. Проведен анализ кинетики образования аустенита в условиях непрерывного нагрева со скоростью 90 оС/с и в ходе изотермической выдержки в межкритическом интервале температур. Определены критические точки АС1 и АС3, найдена энергия активации образования аустенита

RESEARCH OF THE PRE-STRAIN AND ANNEALING EFFECT ON THE STRUCTURE AND MECHANICAL BEHAVIOR OF MEDIUM CARBON STEELS

The influence of pre-strain value of 2 % and subsequent low-temperature annealing at 250 °C on the structure and mechanical properties of medium carbon steels 37G2S and 37HGF.Изучено влияние предварительной деформации величиной 2 % и последующего низкотемпературного отжига при 250 оС на структуру и механические свойства среднеуглеродистых сталей 37Г2 С и 37ХГФ