The pelagic zone of Lake Baikal is an ecological niche where phytoplankton bloom causes increasing microbial abundance in spring which plays a key role in carbon turnover in the freshwater lake. ...Co-occurrence patterns revealed among different microbes can be applied to predict interactions between the microbes and environmental conditions in the ecosystem. We used 454 pyrosequencing of 16S rRNA and 18S rRNA genes to study bacterial and microbial eukaryotic communities and their co-occurrence patterns at the pelagic zone of Lake Baikal during a spring phytoplankton bloom. We found that microbes within one domain mostly correlated positively with each other and are highly interconnected. The highly connected taxa in co-occurrence networks were operational taxonomic units (OTUs) of Actinobacteria, Bacteroidetes, Alphaproteobacteria, and autotrophic and unclassified Eukaryota which might be analogous to microbial keystone taxa. Constrained correspondence analysis revealed the relationships of bacterial and microbial eukaryotic communities with geographical location.
Diatoms synthesize species-specific exoskeletons inside cells under the control of the cytoskeleton and microtubule center. Previous studies have been conducted with the visualization of the ...microtubule center; however, its composition has not been studied and reliably established. In the present study, several components of MTOC in diatoms, GCP (gamma complex proteins), Aurora A, and centrins have been identified. Analysis of the predicted amino acid sequences of these proteins revealed structural features typical for diatoms. We analyzed the conserved amino acids and the motives necessary for the functioning of proteins. Phylogenetic analysis of GCP showed that all major groups of diatoms are distributed over phylogenetic trees according to their systematic position. This work is a theoretical study; however, it allows drawing some conclusions about the functioning of the studied components and possible ways to regulate them.
The composition of bacterial communities in Lake Baikal in different hydrological periods and at different depths (down to 1515 m) has been analyzed using pyrosequencing of the 16S rRNA gene V3 ...variable region. Most of the resulting 34 562 reads of the Bacteria domain have clustered into 1693 operational taxonomic units (OTUs) classified with the phyla Proteobacteria, Actinobacteria, Chloroflexi, Bacteroidetes, Firmicutes, Acidobacteria and Cyanobacteria. It has been found that their composition at the family level and relative contributions to bacterial communities distributed over the water column vary depending on hydrological period. The number of OTUs and the parameters of taxonomic richness (ACE, Chao1 indices) and diversity (Shannon and inverse Simpson index) reach the highest values in water layers. The composition of bacterial communities in these layers remains relatively constant, whereas that in surface layers differs between hydrological seasons. The dynamics of physicochemical conditions over the water column and their relative constancy in deep layers are decisive factors in shaping the pattern of bacterial communities in Lake Baikal.
In this article, we detailed description of changes in the taxonomic composition and quantitative ratio of different groups of microorganisms along the Lake Baikal water column.
Graphical Abstract Figure.
In this article, we detailed description of changes in the taxonomic composition and quantitative ratio of different groups of microorganisms along the Lake Baikal water column.
The complex Iridium(III)bis2-phenylbenzodthiazolato-N,C
2
′-quinolin-8-olate ((bt)
2
Irq) was synthesized and identified by
1
H NMR and IR spectroscopy. Its photophysical, electrochemical and ...electroluminescent properties for White Organic Light-Emitting Diodes (WOLED) application were investigated. It was established that (bt)
2
Irq irradiates yellow-orange light in CH
2
Cl
2
(DCM) solution and solid film with maximum peaks, respectively, at 578 and 666 nm and shoulders at 628 and 720 nm. The complex was used as stand-alone emitter and a dopant in the matrixes of hole transporting layer (HTL) or electroluminescent layer (EL) in the range from 0 to 16.5 w%. The base OLED structure was Anode/HTL/EL/ETL/Cathode, where HTL is N,N′-bis(3-methylphenyl)-N,N′-diphenylbenzidine (TPD) included in a matrix of poly(N-vinylcarbazole) (PVK), EL is Aluminium (III) bis(2-methyl-8-quninolinato)-4-phenylphenolate (BAlq) and ETL is an electron transporting layer of Tris-(8-hydroxyquinoline) aluminium (Alq
3
) or Zinc (II) bis(2-(hydroxyphenyl) benzothiazole (Zn(bt)
2
). It is found that the electroluminescent spectra of both types OLEDs were the sum of the greenish-blue and yellow-orange emissions of BAlq and Ir complex and CIE coordinates of the emitted light remain within the white range over wide dopant concentrations. The best current efficiency and CIE coordinates close to the ideal white (0.3300; 0.3300) demonstrate devices with 2 wt% doped HTL (6 Cd/A, (0.2735; 0.3613)) and 16.5 w% doped EL (5.1 Cd/A, (0.2721; 0.3284)). It was found that both types of doped devices operate through a charge trapping mechanism.
By extending the concept of normal cone for a class of not necessarily convex sets in the
-dimensional Euclidean space, we generalize the concept of system with diode nonlinearities, for which a ...theorem on the existence of a solution of the initial value problem is proved. An example of the problem is given that shows that the uniqueness of the solution does not hold.
This paper presents the results of studies on the development of various technological methods for producing composites based on polytetrafluoroethylene (PTFE) and UVIS-AK-P carbon fibers. The ...methods consist in the physical and ultrasonic actions on the components of polymer composites. The dependence of the physicomechanical and tribotechnical properties on the production technology of polymer composite materials (PCM) based on PTFE and carbon fibers of the UVIS-AK-P brand is investigated. Two technological methods were applied in the present work to improve the distribution of discrete carbon fibers in the polymer matrix: ultrasonic treatment of the powder composition in a dry medium and the technology of introducing the filler into the polymer matrix through a polymer concentrate with carbon fibers (CF). Herewith, the influence of the filler content in the concentrate on the properties of polymer composites is considered. To increase the adhesive interaction of the polymer with filler, the technology of joint activation of the components was used at the stage of obtaining the concentrate. Afterward, the resulting mixture was mixed with a portion of the polymer to the required concentration of the filler. The positive effect of the technology of joint mechanical activation of components on the properties of PCM based on PTFE and UVIS-AK-P carbon fibers has been established. It has been revealed that the composite with a carbon fiber content of 5 wt % obtained using combined mechanical activation of a polymer with CF at a rotational speed of planetary mill drums of 400 rpm with a weight ratio of 50% concentrate and 50% PTFE has optimal properties. The deformation and strength characteristics of this composite is at the level of the initial polymer, and the wear resistance is higher by a factor of 2020 compared with PTFE and 5 compared with a composite obtained by a simple mixed concentration with a polymer.
Molecular Evolution of Tubulins in Diatoms Khabudaev, Kirill V; Petrova, Darya P; Bedoshvili, Yekaterina D ...
International journal of molecular sciences,
01/2022, Letnik:
23, Številka:
2
Journal Article
Recenzirano
Odprti dostop
Microtubules are formed by α- and β-tubulin heterodimers nucleated with γ-tubulin. Tubulins are conserved eukaryotic proteins. Previously, it was shown that microtubules are involved in diatom silica ...frustule morphogenesis. Diatom frustules are varied, and their morphology is species-specific. Despite the attractiveness of the problem of elucidating the molecular mechanisms of genetically programmed morphogenesis, the structure and evolution of diatom tubulins have not been studied previously. Based on available genomic and transcriptome data, we analyzed the phylogeny of the predicted amino acid sequences of diatom α-, β- and γ-tubulins and identified five groups for α-tubulins, six for β-tubulins and four for γ-tubulins. We identified characteristic amino acids of each of these groups and also analyzed possible posttranslational modification sites of diatom tubulins. According to our results, we assumed what changes occurred in the diatom tubulin structures during their evolution. We also identified which tubulin groups are inherent in large diatom taxa. The similarity between the evolution of diatom tubulins and the evolution of diatoms suggests that molecular changes in α-, β- and γ-tubulins could be one of the factors in the formation of a high morphological diversity of diatoms.
The aim of this multicentric retrospective study is to evaluate the predictive and prognostic performance of neutrophil to lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR) and their dynamics ...in patients with non-small cell lung cancer (NSCLC) treated with pembrolizumab as a second line. Patients with metastatic NSCLC (n = 119), whose tumors expressed programmed death-ligand 1 (PD-L1) ≥ 1%, were retrospectively analyzed between Apr 2017 and Apr 2019. All patients received platinum-containing chemotherapy as a first line treatment. Pre-treatment NLR was calculated by dividing the number of neutrophils by the number of lymphocytes in peripheral blood before the first pembrolizumab infusion. Progression free survival (PFS) and overall survival (OS) was compared by Kaplan-Meier method and Cox Proportional Hazard model. Patients with NLR > 5 before immunotherapy showed significantly shorter mean PFS of 6.86 months (95% CI: 5.81-7.90) as compared to those with NLR ≤ 5 of 18.82 months (95% CI: 15.87-21.78) (long rank test p < 0.001). Furthermore in the multivariate analysis, only NLR > 5 was an independent predictive factor for shorter PFS (HR: 4.47, 95% CI: 2.20-9.07, p < 0.001). In multivariate analysis, presence of bone metastases (HR: 2.08, 95% CI: 1.10-4.94, p = 0.030), NLR > 5 before chemotherapy (HR: 8.09, 95% CI: 2.35-27.81, p = 0.001) and high PLR before chemotherapy (HR: 2.81, 95% CI: 1.13-6.97, p = 0.025) were found to be independent negative prognostic factors for poor OS. Our data suggests that NLR ≤ 5 is a potential predictive marker, which may identify patients appropriate for immunotherapy as a second line treatment.
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