Synthesis of two fluorescent GTPγS molecules and their biological relevance

Fluorescent GTP analogues are utilized for an assortment of nucleic acid and protein characterization studies. Non-hydrolysable analogues such as GTPγS offer the advantage of keeping proteins in a GTP-bound conformation due to their resistance to hydrolysis into GDP. Two novel fluorescent GTPγS molecules were developed by linking fluorescein and tetramethylrhodamine to the γ-thiophosphate of GTPγS. Chemical and biological analysis of these two compounds revealed their successful synthesis and ability to bind to the nucleotide-binding site of tubulin. These two new fluorescent non-hydrolysable nucleotides offer new possibilities for biophysical and biochemical characterization of GTP-binding proteins.     

“Lost sugars” — reality of their biological and medical applications

The glycan chains attached to cell surfaces or to single proteins are highly dynamic structures with various functions. The glycan chains of mammals and of some microorganisms often terminate in sialic acids or α-1,3-galactose. Although these two sugars are completely distinct, there are several similarities in their biological and medical importance. First, one type of sialic acid, N-glycolylneuraminic acid, and the galactose bound by an α-1,3-linkage to LacNAc, that forms an α-gal epitope, were both eliminated in human evolution, resulting in the production of antibodies to these sugars. Both of these evolutionary events have consequences connected with the consumption of foods of mammalian origin, causing medical complications of varying severity. In terms of ageing, sialic acids prevent the clearance of glycoproteins and circulating blood cells, whereas cryptic α-gal epitopes on senescent red blood cells contribute to their removal from circulation. The efficiency of therapeutic proteins can be increased by sialylation. Another common feature is the connection with microorganisms since sialic acids and α-gal epitopes serve as receptors on host cells and can also be expressed on the surfaces of some microorganisms. Whereas, the sialylation of IgG antibodies may help to treat inflammation, the expression of the α-gal epitope on microbial antigens increases the immunogenicity of the corresponding vaccines. Finally, sialic acids and the α-gal epitope have applications in cancer immunotherapy. N-glycolylneuraminic acid is a powerful target for cancer immunotherapy, and the α-gal epitope increases the efficiency of cancer vaccines. The final section of this article contains a brief overview of the methods for oligosaccharide chain synthesis and the characteristics of sialyltransferases and α-1,3-galactosyltransferase.     

Bioactive chemicals and biological—biochemical activities and their functions in rhizospheres of wetland plants

Wetland soils provide anoxia-tolerant plants with access to ample light, water, and nutrients. Intense competition, involving chemical strategies, ensues among the plants. The roots of wetland plants are prime targets for root-eating pests, and the wetland rhizosphere is an ideal environment for many other organisms and communities because it provides water, oxygen, organic food, and physical protection. Consequently, the rhizosphere of wetland plants is densely populated by many specialized organisms, which considerably influence its biogeochemical functioning. The roots protect themselves against pests and control their rhizosphere organisms by bioactive chemicals, which often also have medicinal properties. Anaerobic metabolites, alkaloids, phenolics, terpenoids, and steroids are bioactive chemicals abundant in roots and rhizospheres in wetlands. Bioactivities include allelopathy, growth regulation, extraorganismal enzymatic activities, metal manipulation by phytosiderophores and phytochelatines, various pest-control effects, and poisoning. Complex biological-biochemical interactions among roots, rhizosphere organisms, and the rhizosphere solution determine the overall biogeochemical processes in the wetland rhizosphere and in the vegetated wetlands. To comprehend how wetlands really function, it is necessary to understand these interactions. Such understanding requires further research.     

Ecological assessment of running waters: Do macrophytes,macroinvertebrates, diatoms and fish show similar responses to human pressures?

This study aimed to compare the intensity and the sensitivity of the responses of four river biological quality elements (BQEs) – macrophytes, fish, diatoms and macroinvertebrates – to human pressures excluding natural variations in stream ecosystem functioning. Biological, water quality and hydro-morphological data were compiled for 290 French river sites.Out of the 93 metrics tested, 51 covering the four BQEs responded significantly to global degradation. The responses to specific pressures were consistent with the BQEs’ ecological and biological characteristics. For the four BQEs, metrics responded strongly to water quality degradations. Like fish, macroinvertebrate metrics were very sensitive to morphological degradations such as the presence of an impoundment, while diatom and macrophyte metrics did not show strong responses to these changes. Among the four BQEs’ metrics, fish metrics responded the strongest to hydrological perturbations. Although a high proportion of the metrics responded only to high levels of human-induced degradations, trait-based metrics seemed the most sensitive and responded to lower levels of pressure. Global and water quality degradations of the river appear to be better detected by BQE metrics than channel morphological and hydrological degradations. Our results highlight the different impacts of human-induced pressures on the four BQE metrics and the challenging task of assessing the effect of single pressures when most of sites are multi-impacted.     

Periphyton in running waters – long-term studies of natural variation

The objective of this study in River Atna, Norway, was to analyse the spatial and temporal variation in species composition and diversity of the periphyton community in a pristine sub-alpine / boreal watercourse. The variations in the biotic parameters were related to selected environmental factors. We addressed epilithic algae and species living epiphytic on epilithic algae and submerged bryophytes. The sampling sites were located in the alpine, northern boreal, and mid boreal biomes. There was considerable spatial variation in species composition and diversity. This variation showed close correlation with natural gradients in water temperature and nutrient concentration. Three or four periphyton community categories could be distinguished in terms of species composition, diversity, and environmental variables. At high altitudes (1150–740 m a.s.l.) in cold water temperatures and extremely low nutrient contents, there was very low species diversity, only including algae known from ultra oligothrophic cold waters, e.g. Scytonematopsis starmachii (cyanobacteria) and Klebshormidium rivulare (green algae). The second category, at medium altitudes (701–522 m a.s.l.), was characterised by somewhat higher water temperatures and nutrient contents, and the species diversity was higher. This category included algae known from somewhat richer waters, e.g. Stigonema mamillosum (cyanobacteria) and Zygnema spp.(green algae). The third category was located at approx. 522 m a.s.l., had low water temperatures, relatively high alkalinity, and was characterised by Tolypothrix distorta (cyanobacteria) and Ulothrix zonata (green algae). A possible fourth category was found in the lower part of the river (350 m a.s.l.), where periphyton was distinguished by high diversity. At the individual sampling localities, species diversity showed strong seasonal variation, but otherwise high temporal stability. Over the 12 years of observations, there was only a weak temporal trend; towards species initially occurring only at low altitudes and high nutrient content. The combination of high temporal stability and high spatial variability, correlating closely with environmental gradients, is the main reason why periphyton observations have become an important constituent in water quality assessment.     

Harmful cyanobacteria and their cyanotoxins in Egyptian fresh waters – state of knowledge and research needs

Cyanobacterial blooms have increased in freshwater ecosystems worldwide in the last century, mostly resulting from eutrophication and climate change. These blooms represent serious threats to environmental and human health because of the production of harmful metabolites, called cyanotoxins. Like many countries, Egypt has been plagued with cyanobacterial blooms in most water sources, including the Nile River, irrigation canals, lakes and fishponds. However, the data about cyanotoxins produced in these blooms are limited. Only two types of cyanotoxins, microcystins and cylindrospermopsin, have been identified and characterised, mainly from Microcystis and Cylindrospermopsis blooms. The data revealed the presence of microcystins in raw and treated drinking waters at concentrations (0.05–3.8 µg l^?1), exceeding the WHO limit (1 µg l^?1) in some drinking water treatment plants. In addition, Nile tilapia Oreochromis niloticus caught from ponds containing heavy cyanobacterial blooms have accumulated considerable amounts of cyanotoxins in their edible tissues. The data presented here could be the catalyst for the establishment of a monitoring and management programme for harmful cyanobacteria and their cyanotoxins in Egyptian fresh waters. This review also elucidates the important research gaps and possible avenues for future research on cyanobacterial blooms and cyanotoxins in Egypt.     

Entropy and symmetry — their relation to thought processes in the biological system

This paper addresses the topic of the electrophysiology of thought processes in a biological system. A classification and criticism of definitions of intelligence is presented. The engenderment of intelligent regulations of behavior is seen to involve stipulations concerning the relation of metron to logon informational content (MacKay, 1950). The relationship is of a nature similar to that hidden behind the Maxwell demon (Maxwell, 1871), and to certain difficulties already faced in quantum mechanics. As thought structures observe conservation of variety under transformations, the conservation of entropy in thermodynamics is investigated. Conservation occurs in a Carnot cycle (Carnot, 1824) and only under a Lorenz transformation subject to a symmetry group formation. The symmetry group is topic neutral and could be applied to informational structures. The need for the informational equivalents of a Carnot cycle and Lorenz transformations is described. To depict the interaction of energy and structure, equivalents of Einstein's field equations are needed. The study of symmetry groups by electrophysiological methods is seen to be at least feasible.     

Temporal changes of biodiversity in urban running waters – Results of a twelve-year monitoring study

Freshwater biodiversity underlies severe threats, mainly suffering from habitat degradation by anthropogenic land use, in particular by urbanisation. However, recent long-term studies indicate recovery of stream macroinvertebrate diversity due to improved water quality at least in North America and Europe. We monitored macroinverbrates at 56 urban stream sites over a 12-year period (2009–2020) in Braunschweig, a German urban district. We utilised these data to investigate spatio-temporal changes in taxon richness and assemblage structure as well as factors potentially affecting the resulting patterns. Overall taxon richness was increasing over the study period, comprising both all taxa and taxa being indicators for healthy stream conditions. 53.6% of the sites had significant positive trends becoming most eminent since 2014, despite decelerating since 2018, the beginning of an extra-ordinary dry period. Only 10.7% of the study sites had negative trends. Assemblage structure was shaped by environmental factors like stream width and water quality. Over-average taxon richness including positive trends and higher numbers of indicator taxa of healthy stream conditions was found in streams with higher flow velocity, good saprobic conditions and more natural streambed structure. In contrast, low taxon richness and predominance of tolerant taxa were found in streams with more degraded conditions. Most of the environmental conditions having positive effects on taxon richness were improved by various programs set up by the environmental authorities. We therefore conclude, if urban stressors like organic pollution and structural degradation can be mitigated by revitalisation and water quality improvement, urban streams can have good potential for increasing biodiversity and improving ecological functioning.     

Fluorescent oligo and poly-thiophenes and their utilization for recording biological events of diverse origin—when organic chemistry meets biology

The technique of using luminescent oligo-thiophenes and luminescent conjugated poly-thiophenes to monitor biological processes has gained increased interest from scientists within different research areas, ranging from organic chemistry and photo-physics to biology since its introduction. The technique is generally straightforward and requires only standard equipment, and the result is available within minutes from sample preparation. In this review, the syntheses of oligo and polythiophenes developed over the last decades are discussed. Furthermore, the utilization of these molecular agents for exploring biological events, e.g., DNA hybridization or protein misfolding events, are covered.     

Synthesis,characterization and biological studies of sulfonamide Schiff’s bases and some of their metal derivatives

A new series of Schiff base ligands derived from sulfonamide and their metal(II) complexes [cobalt(II), copper(II), nickel(II) and zinc(II)] have been synthesized and characterized. The nature of bonding and structure of all the synthesized compounds has been explored by physical, analytical and spectral data of the ligands and their metal(II) complexes. The authors suggest that all the prepared complexes possess an octahedral geometry. The ligands and metal(II) complexes have been screened for their in vitro antibacterial activity against bacterial strains, Escherichia coli, Shigella flexneri, Pseudomonas aeruginosa, Salmonella typhi and for antifungal activity against fungal strains, Trichophyton longifusus, Candida albicans, Aspergillus flavus, Microsporum canis, Fusarium solani and Candida glabrata. These assays enabled the identification of the metal complexes as an effective antimicrobial agent with low cytotoxicity.     

Habitat requirements of Cardaminopsis petraea — Rare and relict species of the Czech Republic

Vegetation with Cardaminopsis petraea was sampled by phytosociological relevés at almost all the known Czech sites, and characterized by indicator values, influence of potential direct solar irradiation, and bedrock type with the aid of multivariate methods. It has been declared that C. petraea prefers open natural or seminatural drier to mesophilous habitats without some preference to the bedrock. It occupies habitats with various slopes, but it prefers more extreme slants and northerly exposed slopes. The classification and ordination methods showed clear distinction between Moravian and Bohemian habitats. Apart from other types, in Bohemia this species occurs uniquely in acidophilous rock communities, whereas in Moravia it grows uniquely within calcareous grasslands. Relictness of the species was discussed in relation to the specific site conditions (light supply, disturbance regime, and geographical isolation) and to the occurrence of other rare taxa and habitats. Occurrence on some man-made habitats was also observed.     

Polyploidy and aneuploidy of seed plants from the Qinghai–Tibetan Plateau and their biological implications

The Qinghai–Tibetan Plateau is biologically diverse, with 9556 species of vascular plants in the 2,500,000 km² plateau area. We focused on seed plants from the Qinghai–Tibetan Plateau. A total of 9321 species in the Qinghai–Tibetan Plateau were recorded. Sixty-one of these genera are Chinese endemics. Our results suggested that the flora of the Qinghai–Tibetan Plateau was characterized by relatively few polyploids, and aneuploidy was also considered as relatively rare. We inferred that aneuploidy may be affected by environmental factors and the addition or loss of centromeres. Furthermore, the highest frequency of polyploids was found among perennial herbs. Annuals had low polyploidy, and perennials had high polyploidy. Species richness was correlated with the incidence of polyploids, environmental conditions, and reproductive isolation.     

A comparative assessment of biological activities of Gundelia dersim Miller and Gundelia glabra Vitek,Yüce & Ergin extracts and their chemical characterization via HPLC-ESI-TOF-MS

Plants from the Gundelia genus have been well appraised as both food and remedies. The members of the Gundelia genus are widely used as foods in several countries including Turkey. This study presents a comparative assessment of two poorly studied Gundelia species (G. glabra Miller and G. dersim Vitek, Yüce & Ergin). The effect of conventional (infusion, maceration, and Soxhlet extraction) and non-conventional (homogeniser and ultrasound assisted extraction) methods of extraction of bioactive secondary metabolites from the selected Gundelia species was also assessed. A total of 68 different compounds were detected by high-performance liquid chromatography coupled to electrospray ionization and time-of-flight mass spectrometry (HPLC-ESI-TOF-MS) technique. Non-conventional extraction techniques do not guarantee higher antioxidant activity. As such, G. dersim (91.27, 138.87, 182.28, and 125.65 mg TE [Trolox equivalent]/g dried extract, for 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), cupric reducing antioxidant capacity (CUPRAC), and ferric reducing antioxidant power (FRAP) assays, respectively).The highest α-glucosidase inhibition was recorded for the extracts obtained by ultrasonication. In the multivariate analysis, the extracts from Gundelia species were separated based on their biological activities. The presented findings could be one methodological starting point for designing novel products from two Gundelia species.     

Include or exclude? A review on the role and suitability of aquatic invertebrate neozoa as indicators in biological assessment with special respect to fresh and brackish European waters

This paper reviews published knowledge on how to deal with invasive species during biological quality assessments in European river systems for water management and assessments of ecological quality required, for example, by the European Water Frame Work Directive. The papers studied included international papers and some standards for water assessment. An overview of the current state of neozoa research showed that many different topics are treated, comprising biogeography and fauna records, species replacements and effectiveness of colonisation, life cycles, competition between native and invasive species, habitat quality and pathways of migration. Additionally, some papers have been published recently on the integration of neozoa in index-based assessment systems. Although the decline or increase of alien species populations and the corresponding impacts on indigenous populations were frequently observed, the mechanisms behind the invasions often remain hypothetical. In the reviewed papers, issues such as possible reasons for coexistence, tolerances, quality of habitat or water, life history traits and introduction of diseases were rarely covered. Few neozoa are sufficiently investigated to be categorised as indicators. After discussing the advantages and disadvantages of inclusion or exclusion, inclusion of invaders in assessments of both biodiversity (all species) and human impact (only species classified in their specific tolerance) is suggested. Further research is required to (1) update and assign ecological profiles of the non-indigenous species currently and (2) assess the effects of new invaders on native communities.     

Assessment of running waters (Slovakia) using benthic macroinvertebrates — derivation of ecological quality classes with respect to altitudinal gradients

A method is presented for defining the five classes of ecological quality based on a multimetric index (MMI) of macroinvertebrates, as required for implementation of the Water Framework Directive for small (catchment area 10–100 km²), medium (101–1000 km²) and large (> 1000 km²) streams. Our method (expert judgment) allows us to overcome an absence of reference sites for some stream types. The key was selection of suitable metrics for all stream types. The whole procedure was divided into two parts. 1. Small streams with reference sites: suitable metrics were selected according to their ability to distinguish reference and monitoring sites — SI, Oligo [%], BMWP, RhiTI, Rheoindex, IBCR, % Aka+Lit+Psa [%] and EPT. Here the high-good boundary value was set as the 25^th (for metrics decreasing with increasing pollution) or 75^th percentile (for metrics increasing with increasing pollution). 2. Medium and large streams which lack reference sites: here the idea was applied that some metrics, the values of which change along an altitudinal gradient, also react to anthropogenic stress — SI, Oligo [%], BMWP, [%] metarhithral, RhiTI, Aka+Lit+Psa [%] and EPT for both medium and large streams with, in addition, IBCR and NFam for medium streams. This assumption was supported by regression analysis of altitude and metrics from small streams. Not all the metrics were related to altitude but metrics with a good ability to separate reference and monitoring sites did show a significant relationship to altitude. The boundary between high and good class for medium and large streams was set as the 95^th or 5^th percentiles.     

Impact of climatic variability on parameters used in typology and ecological quality assessment of surface waters—implications on the Water Framework Directive

In most cases the negative impacts of climate change to aquatic ecosystems cannot be mitigated by measures in the river basin management. Ignoring climate change by the Water Framework Directive may have strong implications for the typology and quality assessment systems used for water bodies. As a result of climate change, water bodies, especially those located near the type boundaries may change their type. Compared to typology characteristics, water quality parameters are even more labile and may be easily affected by climate change. The paper exemplifies that the anticipated deterioration of water quality within the time frame relevant for WFD implementation may be large enough to endanger the fulfillment of the set water quality objectives. The review of the river basin characterization every six years, as required by the WFD, might also include re-evaluation of reference conditions according to the changes observed at pristine reference sites. As a consequence, the restoration targets (i.e., the good ecological status) would also need to be evaluated periodically.