Latest Articles from BioRisk Latest 6 Articles from BioRisk https://biorisk.pensoft.net/ Thu, 28 Mar 2024 23:19:24 +0200 Pensoft FeedCreator https://biorisk.pensoft.net/i/logo.jpg Latest Articles from BioRisk https://biorisk.pensoft.net/ Evaluation of abundance of microplastics in the Bulgarian coastal waters https://biorisk.pensoft.net/article/97555/ BioRisk 20: 59-69

DOI: 10.3897/biorisk.20.97555

Authors: Stanislava K. Georgieva, Zlatina V. Peteva, Mona D. Stancheva

Abstract: Plastic pollution in seawaters is ubiquitous, but quantitative estimates on the floating microplastics in the Black Sea are still limited. Plastics may adsorb persistent environmental contaminants, thus representing a potential risk for marine organisms. Aim: Thе aim of the study was evaluation of the presence and characteristics of microplastic particles (MPs) in waters from the Black Sea coast of Bulgaria. Materials and methods: Samples of coastal waters were collected from March 2021 to April 2022 from different stations on the Black Sea coast, including protected, aquaculture and industrial areas. In order to determine the number of plastic particles, 23 samples were collected from the surface waters at depth of 1–3 m close to the Bulgarian shore. Samples were treated with H2O2, plastic particles were isolated by density separation and filtered over a membrane filter. Identification analysis of micro particles (< 5 mm) was performed visually by microscopy. Main results: Results indicated widespread presence of microplastics in coastal waters. Mean MPs concentration was calculated 7.3 ± 4.9 pt/l. The comparison of the North, Varna and South sampling area showed that there is no significant difference in the abundance of plastic particles. The most dominant type forms were fibres followed by fragments. The most abundant size class of fragments was 101–500 μm Ferret diameter. Conclusion: Further studies are needed in order to fill knowledge gap and to evaluate distribution of plastic particles in the Black Sea and their potential ecological risk.

HTML

XML

PDF

]]>
Research Article Mon, 15 May 2023 20:00:05 +0300
Does overproduction of chaperone proteins favour the repair of DNA injuries induced by oxidative stress? (Mini review) https://biorisk.pensoft.net/article/97569/ BioRisk 20: 7-22

DOI: 10.3897/biorisk.20.97569

Authors: Stephka G. Chankova, Nadezhda P. Yurina, Teodora I. Todorova, Petya N. Parvanova

Abstract: Genotype resistance to oxidative stress, induced by various physical/chemical stimuli has been the focus of scientists for the last decades, with several aspects – ecological (the formation of the genetic elite of population), agricultural and medical (radio-chemotherapy). Genotype resistance to oxidative stress is regarded as the integration of different morphological, physiological, biochemical, metabolic and genetic characteristics. Currently, it is supposed that the mechanisms involved in the formation of genotype resistance to oxidative stress are inter-correlated and inter-dependent, comprising changes in genes, proteins, enzymes, different metabolic pathways and/or biological networks. According to the present state of knowledge, various cellular targets, resulting in genotoxic stress, induction of DNA damage, mutations, genomic instability or apoptosis can trigger different signal transduction pathways, activating DNA repair, antioxidant and chaperone defence systems. Till now, a lot of experimental data have been accumulated concerning the contribution of DNA repair to the formation of genotype resistance to oxidative stress. At the same time, genotype resistance of organisms is largely determined by the ability of molecular chaperones to maintain conformational homeostasis of proteins (folding – misfolding – refolding or aggregation – degradation). The role of chaperones in protein homeostasis and cell death, especially in apoptosis, is well discussed in literature, but much less is known about their function in DNA repair. In this regard, here we addressed the question of whether the overproduction of chaperone proteins contributes to the repair of DNA damage caused by oxidative stress.

HTML

XML

PDF

]]>
Review Article Mon, 15 May 2023 20:00:02 +0300
Polar and non-polar fraction from Origanum vulgare spp. hirtum methanolic extract – differences in their bioactivity on Chlamydomonas reinhardtii test system https://biorisk.pensoft.net/article/78169/ BioRisk 17: 191-200

DOI: 10.3897/biorisk.17.78169

Authors: Maria Dimitrova Todorova, Petya Nikolaeva Parvanova, Teodora Ivanova Todorova, Milena Tihomirova Nikolova, Strahil Hristov Berkov, Stephka Georgieva Chankova

Abstract: Aim: To compare the bioactivity of both polar and non-polar fraction of Origanum vulgare spp. hirtum methanolic extract on Chlamydomonas reinhardtii. Material and methods: The polar and non-polar fractions were derived from aerial parts of Origanum vulgare ssp. hirtum, collected during the flowering stage from the ex-situ collection of IBER-BAS. GC/MS analysis of both fractions was done following the standard protocol. The measured mass spectra were deconvoluted by the Automated Mass Spectral Deconvolution and Identification System (AMDIS), before comparison with the databases. Chlamydomonas reinhardtii 137C+ (WT) was used as a test system. Spot-test, cell survival fraction (SF), test of “visible mutations” and CFGE (for measurement of induced DNA double-strand breaks (DSBs)) were applied. Results: The polar fraction did not possess genotoxic, mutagenic as well as DNA-damaging effect. The situation with the non-polar fraction was quite different. Even at the lowest concentration of 250 ppm, cell survival was decreased by 60% (SF = 0.41 ± 0.08). Treatment with concentrations equal to/or greater than 500 ppm resulted in around 100% lethality. A mild mutagenic effect was obtained for the concentration of 250 ppm non-polar fraction (IM = 4.83 ± 0.004). Well-expressed and concentration-dependent induction of DSBs for even the strong DNA fragmentation was observed after the treatment with the non-polar fraction. Conclusions: The different bioactivity of the two fractions correlated well with their different chemical composition. The polar fraction, rich in sugars, organic acids and flavonoid glycosides, did not possess genotoxic and mutagenic potential. The strong genotoxic potential of the non-polar fraction might be related to carvacrol content (37.08%), which is not present in the composition of the polar fraction. To the best of our knowledge, this study provides the first information that the carvacrol-rich non-polar fraction of Origanum vulgare spp. hirtum methanolic extract possesses genotoxic, mutagenic and DNA damaging effect on some low eukaryotes, such as C. reinhardtii. Further experiments with carvacrol should be done in order to clarify the exact mechanism of action.

HTML

XML

PDF

]]>
Research Article Thu, 21 Apr 2022 19:00:18 +0300
On the mode of action of Origanum vulgare spp. hirtum methanolic extract and essential oil on Chlamydomonas reinhardtii https://biorisk.pensoft.net/article/77313/ BioRisk 17: 179-190

DOI: 10.3897/biorisk.17.77313

Authors: Maria D. Todorova, Petya N. Parvanova, Teodora I. Todorova, Georgi D. Dronchev, Milena T. Nikolova, Strahil H. Berkov, Stephka G. Chankova

Abstract: Aim: To reveal whether methanolic extract and essential oil from Origanum vulgare subsp. hirtum in doses causing even low levels of mortality in aphids, would have harmful effects on plants-genotoxic, mutagenic and/or DNA damaging. Materials and methods: Aerial parts of Origanum vulgare ssp. hirtum from the ex-situ collection of IBER, BAS during flowering were collected. Extraction and isolation procedures, as well as GC/MS analysis of essential oil and methanolic extract were performed by standard protocols. The components were identified by comparing their relative retention times to the retention times of authentic standards, and with mass spectra with the NIST. Test system: Chlamydomonas reinhardtii strain 137 C+ (WT). Endpoints: “clonal” assay, the test of “visible mutations”, constant field gel electrophoresis. Statistics: GraphPad Prism version 6.04 (San Diego, USA) and One-way Analysis of Variance ANOVA with multiple comparisons using the Tukey method. Results: A good correlation was observed between chemical composition of essential oil and methanolic extract, and their mode of action. Our genotoxic and double strand breaks results demonstrated mild genotoxic and statistically non-significant DNA damaging potential of methanolic extract and concentration-dependent well - expressed genotoxic and DNA damaging potential of essential oil. A good relationship between increased double strand breaks levels and decreased survival might be related to one of the main constituents of essential oil, suspected to be carvacrol. No mutagenic effect for ME and EO was found. Conclusion: Well-expressed toxic/genotoxic capacity of essential oil, as well as its capacity to damage DNA inducing double strand breaks, but the absence of mutagenic potential, could be considered as a good reason to recommend Origanum vulgare subsp. hirtum essential oil as a promising candidate for purposes of “green” technologies.

HTML

XML

PDF

]]>
Research Article Thu, 21 Apr 2022 19:00:17 +0300
Key Biodiversity Areas: Rapid assessment of phytoplankton in the Mesopotamian Marshlands of southern Iraq https://biorisk.pensoft.net/article/1834/ BioRisk 3: 111-126

DOI: 10.3897/biorisk.3.20

Authors: Ghasak Al-Obaidi, Suad Salman, Clayton Rubec

Abstract: Between the summers of 2005 and 2007, studies have been conducted for five seasons in several marsh locations in southern Iraq. During five surveys, 317 taxa of phytoplankton belonging to six major groups were identified. These included: 204 taxa of Bacillariophyceae (represented by 13 Centrales and 191 Pennales, thus 14% and 27% respectively of all taxa recorded), 59 Chlorophyta (28%), one Cryptophyta (4%), 39 Cyanophyta (21%), 10 Euglenophyta (2%) and four Pyrrophyta (4% of all the taxa recorded). The Central Marsh, Hammar Marsh and the Hawizeh Marsh had higher phytoplankton populations compared to all other studied sites. The dominant phytoplankton groups throughout the study area were the Bacillariophyceae, Chlorophyta and Cyanophyta. The dominant species were Cyclotella meneghiniana, Kirchneriella irregularis and Nitzschia palea. A progression in the richness and biodiversity of species occurred during winter. These three phytoplankton groups were dominant in waters of southern Iraq and were responsible for most of the species richness and diversity observed. Generally, sites changed from summer to winter according to the changing conditions associated with nutrients, salinity, temperature, and light intensity. These controlling factors influenced phytoplankton biomass from season to season.

HTML

PDF

]]>
Research Article Mon, 28 Dec 2009 00:00:00 +0200
Space-time variability of phytoplankton structure and diversity in the north-western part of the Arabian Gulf (Kuwait) https://biorisk.pensoft.net/article/1832/ BioRisk 3: 86-96

DOI: 10.3897/biorisk.3.8

Authors: Igor Polikarpov, Faiza Al-Yamani, Maria Saburova

Abstract: Studies of the phytoplankton community were conducted in the north-western Arabian Gulf in 2005 and 2006. Seven stations throughout Kuwait’s waters were sampled. The influence of nutrient-rich freshwaters from the Shatt al-Arab resulted in high phytoplankton productivity characterized by high species diversity with a strong dominance of diatoms, especially in northern Kuwait. Phytoplankton species richness gradually increased from north to south. Spatial distribution of both total abundance and biomass of phytoplankton indicated significant differences in species structure and size spectrum of the microalgae. The analysis of the temporal and spatial phytoplankton variability (distribution of total abundance and biomass, similarity of species compositions and local community structure) indicated that Kuwait’s northern waters differed from areas further south in terms of phytoplankton structure and temporal and spatial variability. Environmental heterogeneity is mainly attributed to the influence of the Shatt al-Arab system, which affects the temporal and spatial variability of the phytoplankton community.

HTML

PDF

]]>
Research Article Mon, 28 Dec 2009 00:00:00 +0200