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Antioxidative Responses of Microalgae to Heavy Metals

Abstract

Microalgae are unicellular free living entities and therefore their responses to excess of heavy metals must be faster and more efficient than those in vascular plants protected by various types of tissues. Up to date, numerous studies reported metal bioaccumulation potential of algae but metabolic responses have relatively rarely been monitored. Here I provide basic overview of quantitative changes of ascorbic acid (AA), reduced glutathione (GSH), phytochelatins (PCs) and selected related enzymes (ascorbate peroxidase and glutathione reductase) in some common microalgae exposed to various metals (cadmium mainly). Despite various culture and exposure conditions, some common signs of metal toxicity (including e.g. enhancement of phytochelatin biosynthesis) are clearly identifiable in algae. Other metal chelators such as organic acids are also briefly mentioned. Comparison with macroalgae, mosses and vascular plants is discussed in terms of basal values and evolutionary similarities.

Open access
Application of Fuzzy Rayleigh Distribution in the Nonisothermal Pyrolysis of Loose Biomass

Abstract

This paper studied the implementation of fuzzy logic on the relevant parameter of biomass pyrolysis. Frequency factor, the upper limit of ‘dE’, and the scale parameter of Rayleigh distribution are fuzzified in order to estimate the randomness in estimating the parametric values. Distribution function, f(E), of activation energies is assumed to follow the Rayleigh distribution. Thermo-analytical data has been found experimentally with the help of TGA/DTG analysis. The approximated solution of distributed activation energy model (DAEM) is obtained by using asymptotic approach.

Open access
How the Management May Affect Dispersal of Slender Speedwell (Veronica filiformis Smith) in Meadows and Pastures

Abstract

Slender speedwell (Veronica filiformis Smith, family Plantaginaceae) is a non-native and invasive species of grassland in the Europe. The aim of the study was to test the ability of the growth and spreading in nine differently managed grasslands (mowing, mulching, grazing). The best survival was found in two-years mowed lots with fertilisation and in all lots with not permanent cattle pasture crops. There were found the highest number of survived plants and plants with big “rosette“ diameters. Number of survived plant for two seasons was 18 and total number of vegetative peaks per plant was 688. The potential for the spreading of such plant population is great. On the other hand, plants did not survived in lots with mulch treatment and in fenced lots with permanent cattle grazing.

Open access
Molecular Characterization of ESBL Gene in Citrobacter Spp and Antibacterial Activity of Omega-3 Against Resistant Isolates

Abstract

This study aimed to investigated the prevalence and resistance pattern of different Citrobacter species phenotypically and genotypically to β-lactam and some most common antibiotics then evaluate the antibacterial activity of omega-3 extracted from flaxseed against isolates that harboring resistance genes. 19 Citrobacter isolates were isolated from100 stool and urine samples taken from patients attended to AL-Sadar Hospital during June-December 2016. Clinical samples were cultured on specific media, thereafter isolates were identified depending on morphological, biochemical characteristics and VITK-2. The results showed that the Citrobacter comprise 24% of isolated bacteria which divided into 11 (14.1%) were C. freundii, 5 (6.41%) C. kosaeri and C. farmeri were 3 (3.8%). The antagonistic activity was evaluated by observing a clear zone of inhibition growth, the results showed that all Citrobacter (100%) isolates were resistant to Ampicillin, cefoxitin and sensitive to Imipinim, also the isolates showed different degrees of resistant to β-lactam antibiotics initially. By confirmatory test the results observed 17/19 (89.4%) isolated were ESBL producers finally using PCR technique to detect bla–genes (blaCTX-M, OXA, SHV and Z). The results revealed that 14/17 (82.3) of potential ESBL producing Citrobacter were harbor one or more of ESBL genes they included 10 of C. freundii and 4 of C. koseri. The extraction of essential fatty acid semicarbazide (omega-3) from Linum usitatissium (Flax seed) were tested to evaluate their activity against resistant isolates, results explained broad spectrum antibacterial property of EFASC compounds against resistant bacteria. In conclusion, this study found increase prevalence of MDR Citrobacter spp as causative agents in clinical cases. Considering antibacterial activity of EFASC, it was observed highly activity against resistant pathogens deservedly, therefore attention must be paid to development their used as alternative antibiotics.

Open access
Bioleaching of Arsenic and Antimony from Mining Waste

Abstract

This paper is a contribution to quantification of bio-leached arsenic and antimony from mining waste collected from impoundment in Slovinky (Slovakia). Autochtonous fungal strain Aspergillus niger was used in all bioleaching experiments. The contents of arsenic and antimony in two different samples from the impoundment were 294.7 and 328.2 mg.kg−1 As and 225.3 and 285.7 mg.kg−1 Sb, respectively. After 21-day cultivation of Aspergillus niger on such contaminated substrates, this strain was capable to bioleach, bioaccumulate and biovolatilize both toxic elements.

Open access
Contents of Potentially Toxic Metals and Magnetic Susceptibility of Soils Along a Rural – Urban – Rural Gradient in Bratislava City (Slovakia)

Abstract

The concentrations of potentially toxic metals (As, Cd, Cu, Hg, Pb, Zn and Fe) and the values of magnetic susceptibility in surface soils were measured along NW-SE gradient in Bratislava city (rural – urban – rural soils). The results indicate that both the contents of potentially toxic metals (PTMs) and the values of magnetic susceptibility decrease with increasing distance from the city centre in both directions. Urban soils are enriched mainly in Cu, Hg, Pb and Zn. Their elevated concentrations in soils within the city are due to accumulation from anthropogenic activities. There was a statistically significant and positive correlation between the mean values of Tomlinson pollution load index (PLI) and the mean values of magnetic susceptibility in soil samples. This correlation shows that the monitoring of magnetic properties of soils can be used as a rapid and non-destructive tool for the effective determination of environmental pollution in urbanized regions affected by anthropogenic activities.

Open access
Ecological Risk Assessment Framework

Abstract

Purpose of this paper is to draft shot information about framework for ecological risk assessment compile according Guidelines and short description of phases from which this method consists. During description of particular procedures, the meaning of used terms is introduced and explained. The framework for risk assessment is presented as a useful tool for risk management and selection of available cleanup and remedy technologies, and costs of alternative actions.

Open access
On the Occurrence of the Introduced Pest Thrips simplex () (Thysanoptera: Thripidae) in Slovakia

Abstract

Exotic species introduction has recently increased European insect diversity in accordance with global climate change and international biological commodity trade, often with serious environmental and economic consequences for natural ecosystems as well as urban and farmland area. This short communication deals with the first official faunistic record of the gladiolus thrips Thrips simplex (Morison, 1930) (Thysanoptera, Thripidae) in Slovakia.

Open access
Response of Tomato Plants (Solanum lycopersicum) to Stress Induced by Sb(III)

Abstract

Presented study evaluates effects of various Sb(III) concentrations on tomato plants (Solanum lycopersicum) cultivated hydroponically. Visual symptoms of antimony toxicity were observed only at two highest applied concentrations (50 and 100 mg/L). Dry weight of aboveground parts decreased significantly in variants treated with 25, 50 and 100 mg/L Sb(III), by ~12, 35 and 65 %, respectively, in comparison to the control. Statistically significant decrease of chlorophyll a and b was observed only after application of two highest studied concentrations 50 and 100 mg/L Sb(III). On the other hand concentration of total carotenoids in leaves rose with increasing external Sb(III) concentration. High concentrations (50 and 100 mg/L) of Sb(III) in nutrient solution caused that protein content in leaves dropped by ~20 and 39% relative to control. Accumulation of antimony in roots was about 5- (10 mg/L) to 27-times (25 mg/L) greater than that in shoots. The highest BAF factor value determined for shoots was ~55 at 10 mg/L Sb(III) and for roots it was ~821 at 50 mg/L Sb(III). Translocation factor values were in whole studied concentration range 5 – 100 mg/L Sb(III) < 1. The most effective translocation of antimony from roots to shoots was observes for variants treated with 10 mg/L of Sb(III).

Open access