Mechanisms of regulation of invasive processes in phytoplankton on the example of the north-eastern part of the Black Sea

© 2016, Springer Science+Business Media Dordrecht. In the north-eastern part of the Black Sea, the seasonal complexes of dominant species of phytoplankton were fixed: small-celled diatom (spring), coccolithophores (late spring, early summer) and large diatoms (summer and autumn). In May–June 2005 and 2006, two invasive species of marine diatoms Chaetoceros throndsenii (maximal abundance 1.92 × 105 cells/l) and Chaetoceros minimus (1.6 × 105 cells/l) were recorded. These species have been incorporated in the complex of the late spring and early summer and grew simultaneously with the coccolithophore Emiliania huxleyi. The coccolithophore was dominant species, whose abundance had reached the level of a bloom. C. throndsenii was observed over the entire area from the coast to the centre of the sea; C. minimus were recorded at coastal stations and only at two stations of the open sea. Stratification of the water mass and the low (below the Redfield) ratio of nitrogen to phosphorus were observed at this time. Then, C. throndsenii was not marked even once, and C. minimus has been registered once on a shelf in June 2011. Experimental studies (2005) have shown that intensive growth C. throndsenii requires the simultaneous addition of nitrogen and phosphorus in a ratio close to the Redfield ratio. C. minimus shows the intensive growth only at high concentrations of phosphorus and at low nitrogen-to-phosphorus ratio (the experiment was carried out in June 2011). Mathematical modelling shows that C. throndsenii and Emiliania huxleyi form a stable couple whose growth is limited by different factors: the diatoms by nitrogen and the coccolithophores by phosphorus. C. minimus might not be able to form a stable couple with coccolithophores because they have the same limiting factor, i.e. phosphorus. However, this species could become the dominant one, if low (0.5–1) nitrogen-to-phosphorus ratio conditions were stable for more than 2 months. However, this scenario is improbable in natural circumstances since the existence of this complex seasonal rarely exceeds 1.5 months

Norleucine, a natural occurrence in a novel ergot alkaloid γ-ergokryptinine

A novel natural peptide ergot alkaloid γ-ergokryptinine containing norleucine has been isolated from ergot sclerotia of the field-growing parasitic fungus Claviceps purpurea CCM 8059. Its structure was deduced from the NMR and mass spectral data. The final structural proof was provided by the crystal structure determination, which is the first X-ray structure of a natural Nle-containing secondary metabolite. The conformations of three ergopeptinines: γ-ergokryptinine, ergoladinine, and α-ergokryptinine were compared. © Springer-Verlag 2005

Disassembly of Actin Structures by Nanosecond Pulsed Electric Field is a Downstream Effect of Cell Swelling

Disruption of the actin cytoskeleton structures was reported as one of the characteristic effects of nanosecond-duration pulsed electric field (nsPEF) in both mammalian and plant cells. We utilized CHO cells that expressed the monomeric fluorescent protein (mApple) tagged to actin to test if nsPEF modifies the cell actin directly or as a consequence of cell membrane permeabilization. A train of four 600-ns pulses at 19.2 kV/cm (2 Hz) caused immediate cell membrane poration manifested by YO-PRO-1 dye uptake, gradual cell rounding and swelling. Concurrently, bright actin features were replaced by dimmer and uniform fluorescence of diffuse actin. To block the nsPEF-induced swelling, the bath buffer was isoosmotically supplemented with an electropore-impermeable solute (sucrose). A similar addition of a smaller, electropore-permeable solute (adonitol) served as a control. We demonstrated that sucrose efficiently blocked disassembly of actin features by nsPEF, whereas adonitol did not. Sucrose also attenuated bleaching of mApple-tagged actin in nsPEF-treated cells (as integrated over the cell volume), although did not fully prevent it. We conclude that disintegration of the actin cytoskeleton was a result of cell swelling, which, in turn, was caused by cell permeabilization by nsPEF and transmembrane diffusion of solutes which led to the osmotic imbalance

Future physical education teachers’ marketing business motivations survey

Objective of the study was to survey marketing business motivations of future physical education teacher

The development of a toxicity database using freshwater macroinvertebrates, and its application to the protection of South African water resources

There is a growing international trend towards the protection of freshwater resources from pollution by imposing instream guidelines and specified waste-discharge conditions. Current methods for devising freshwater quality guidelines are based on species sensitivity distributions (SSDs) that are used to identify pollutant concentrations, ensuring the protection of a modelled percentage of species (95% protection is a common goal). SSDs are derived from the toxicity test results of as many taxa as possible for each polluting substance. Waste-discharge licences can be for single substances, specified in terms of chemical concentrations, and derived in conjunction with instream guidelines; or for complex mixtures, specified in terms of toxic units. In both cases toxicity test results are the core data used. The emphasis on SSDs calls into question the species constituting the test populations. It is likely that SSDs based in part on the responses of local organisms will achieve superior site-specific ecological protection. Until the early 1990s, there were very few data on the tolerances of South African freshwater organisms. In the intervening decade, the Unilever Centre for Environmental Water Quality at Rhodes University has developed a toxicity database that, to date, records the responses of 21 South African freshwater taxa to 26 single-substance pollutants or mixtures. This is the most comprehensive database of South African toxicity responses available and has been used in the drawing up of methods and guidelines to protect water resources. This paper aims to make these data available and to describe applications of the data using selected case studies

Dose-Dependent Thresholds of 10-ns Electric Pulse Induced Plasma Membrane Disruption and Cytotoxicity in Multiple Cell Lines

In this study, we determined the LD50 (50% lethal dose) for cell death, and the ED50 (50% of cell population staining positive) for propidium (Pr) iodide uptake, and phosphatidylserine (PS) externalization for several commonly studied cell lines (HeLa, Jurkat, U937, CHO-K1, and GH3) exposed to 10-ns electric pulses (EP). We found that the LD50 varied substantially across the cell lines studied, increasing from 51 J/g for Jurkat to 1861 J/g for HeLa. PS externalized at doses equal or lower than that required for death in all cell lines ranging from 51 J/g in Jurkat, to 199 J/g in CHO-K1. Pr uptake occurred at doses lower than required for death in three of the cell lines: 656 J/g for CHO-K1, 634 J/g for HeLa, and 142 J/g for GH3. Both Jurkat and U937 had a LD50 lower than the ED50 for Pr uptake at 780 J/g and 1274 J/g, respectively. The mechanism responsible for these differences was explored by evaluating cell size, calcium concentration in the exposure medium, and effect of trypsin treatment prior to exposure. None of the studied parameters correlated with the observed results suggesting that cellular susceptibility to injury and death by 10-ns EP was largely determined by cell physiology. In contrast to previous studies, our findings suggest that permeabilization of internal membranes may not necessarily be responsible for cell death by 10-ns EP. Additionally, a mixture of Jurkat and HeLa cells was exposed to 10-ns EP at a dose of 280 J/g. Death was observed only in Jurkat cells suggesting that 10-ns EP may selectively kill cells within a heterogeneous tissue

Maximal and repeated muscular efforts: ergometric and physiological evaluation criteria

The pre-versus post-experimental 5s maximal strength tests of the isometric contractions of rectus femoris found significant progress in the following test rates: peak force by 10.4%; maximal strength by 13.3% and force impulse by 15.5%. The pre-versus post-experimental 1min maximal strength keeping tests found significant progress in the following test rates: peak force by 11.2%; maximal strength by 15.2%; maximal strength reaching time by 14.6%; and the 97% maximal strength reaching time by 15.8

Experimental animal models of scoliosis for understanding the etiology of idiopathic scoliosis

Idiopathic scoliosis is a common disease of the musculoskeletal system, affecting 2–3% of children and adolescents worldwide. The etiology and pathogenesis of scoliotic spinal deformity have not yet been disclosed, despite numerous long-term studies. Animal modeling of scoliosis can become the basis for studying possible etiological factors and pathogenetic mechanisms of the formation of the pathology in question and the prospects for possible treatment of scoliosis in the future. To date, many different types of models of scoliotic disease have been created and studied. The purpose of this review was to analyze the literature data on animal modeling of scoliosis in order to understand the etiological factor of idiopathic scoliosis in humans. Material and methods. The review was carried out using databases of electronic information resources PubMed (MEDLINE), Scopus, eLibrary.ru. The analysis of scientific literature was carried out according to the search words: “idiopathic scoliosis”, “experimental model of scoliosis”, “animal model of scoliosis”, “mechanical models of scoliosis”, “pineal gland resection models”, “genetic models of scoliosis”. Results. The analysis of scientific literature data confirms the high importance of experimental animal models of scoliosis for the study of the etiology of idiopathic scoliosis. The review summarizes and analyzes data on the main directions of modeling scoliotic deformity: mechanical, neuroendocrine and genetic models. Conclusions. The models of scoliosis presented in the literature have been implemented with varying degrees of success and have not been able to clarify the etiology of spinal pathology, but they are a useful tool for testing interventions aimed at correcting and preventing deformity. The development of an optimal experimental model of scoliosis in animals will further overcome the existing limitations in determining the etiological factor of idiopathic scoliosis and describe the processes of disease development characteristic of humans

OPPORTUNITIES FOR DEVELOPMENT OF ROBOTICS IN SVERDLOVSK REGION

The analysis of conditions allowing to develop robotics in the Sverdlovsk region

Congenital dislocation of the hip – theories, etiological and predisposing factors (risk factors)

According to current statistics worldwide, congenital orthopedic pathologies rank second quantitatively after congenital diseases of the nervous system. Congenital dislocation of the hip is one of the most common and severe pathologies of the musculoskeletal system in children and adolescents. The theories of its development and etiological factors are not only of historical interest but also create prerequisites for determining the true cause of this complex process. The problem of predicting the development of hip dysplasia remains relevant. The practical significance lies in determining the etiological factor (predisposing or risk factors) of the disease onset or manifestation. Analysis of the literature suggests that hip dysplasia is based on a genetic substrate as an etiological factor. Predisposing factors only increase the risk of pathology manifestation. Further studies to determine the etiological factor will make it possible to formulate more specific recommendations for the management of patients with hip dysplasia and possibly expand the methods of prevention and conservative treatment