Microcystin concentration in fishpond waters

Cyanobacterial blooming is a worldwide problem which sometimes results in cyanotoxin production. Most commonly produced cyanotoxins are microcystins (MCs), potent inhibitors of protein phosphatases. Protein phosphatase 1 (PP1) is known to be involved in the regulation of a variety of cellular processes. In this study, MC concentration was assessed via inhibition of protein phosphatase 1 (PP1 assay) in water samples taken from 14 lakes of Mužlja fishpond, Vojvodina, Serbia. During the summer of 2011, cyanobacterial growth occured in the fishpond lakes and small, planktonic crustacean Daphnia sp. was used to control or/and prevent further development of cyanobacteria. Different MC concentrations (calculated as microcystin-LR equivalents) were detected, mostly depending on the occurrence and grazing of Daphnia sp. More thorough monitoring of fishponds should be conducted, both in Serbia and around the world, in order to gain more precise estimation of cyanotoxin concentrations and their accumulation in organisms used for human consumption and thus prevent possible negative health effects. [Projekat Ministarstva nauke Republike Srbije, br.176020

Detection of phosphatase activity in aquatic and terrestrial cyanobacterial strains

Cyanobacteria, as highly adaptable microorganisms, are characterized by an ability to survive in different environmental conditions, in which a significant role belongs to their enzymes. Phosphatases are enzymes produced by algae in relatively large quantities in response to a low orthophosphate concentration and their activity is significantly correlated with their primary production. The activity of these enzymes was investigated in 11 cyanobacterial strains in order to determine enzyme synthesis depending on taxonomic and ecological group of cyanobacteria. The study was conducted with 4 terrestrial cyanobacterial strains, which belong to Nostoc and Anabaena genera, and 7 filamentous water cyanobacteria of Nostoc, Oscillatoria, Phormidium and Microcystis genera. The obtained results showed that the activity of acid and alkaline phosphatases strongly depended on cyanobacterial strain and the environment from which the strain originated. Higher activity of alkaline phosphatases, ranging from 3.64 to 85.14 μmolpNP/s/dm3, was recorded in terrestrial strains compared to the studied water strains (1.11-5.96 μmolpNP/s/dm3). The activity of acid phosphatases was higher in most tested water strains (1.67-6.28 μmolpNP/s/dm3) compared to the activity of alkaline phosphatases (1.11-5.96 μmolpNP/s/dm3). Comparing enzyme activity of nitrogen fixing and non-nitrogen fixing cyanobacteria, it was found that most nitrogen fixing strains had a higher activity of alkaline phosphatases. The data obtained in this work indicate that activity of phosphatases is a strain specific property. The results further suggest that synthesis and activity of phosphatases depended on eco-physiological characteristics of the examined cyanobacterial strains. This can be of great importance for the further study of enzymes and mechanisms of their activity as a part of cyanobacterial survival strategy in environments with extreme conditions. [Projekat Ministarstva nauke Republike Srbije, br. III 43002

Tretman natrijum-alginatom kao način da se poboljšaju sorpciona svojstva sirove tkanine jute

Sodium alginate aqueous solutions of different concentrations (0.5, 1.0, or 2.0%) were used for improving the sorption properties (evaluated through the determination of water retention power (WRP) and wetting time (WT)) of raw jute fabric. The influence of drying conditions (never-dried samples, samples dried at 60 °C or at room temperature) on the sorption properties of alginate-treated jute fabrics was also studied. Independently on the examined method (centrifuge or water absorption method), the same trend of improvement in WRP of alginate-treated fabrics was observed. The WRP of never-dried fabric treated with 2.0% sodium alginate solution determined using the water absorption or centrifuge method increased by 4.8 or 3.3 times compared to raw jute fabric, respectively. Moreover, the WT of jute fabrics decreased from 206.9±6.6 s down to 1.7±0.1 s after the treatment with 0.5% sodium alginate solution. The improved sorption properties of alginate-treated jute fabrics are attributed to the alginate layer on the fabric surface having a higher number of accessible carboxyl groups as well as hydroxyl groups capable of forming new hydrogen bonds with water molecules.Vodeni rastvori natrijum-alginata različitih koncentracija (0,5, 1,0 ili 2,0%) korišćeni su za poboljšanje sorpcionih svojstava (procenjenih određivanjem sposobnosti zadržavanja vode (WRP) i vremena kvašenja (WT)) sirove tkanine jute. Takođe je proučavan uticaj uslova sušenja (neosušeni uzorci, uzorci sušeni na 60 °C ili na sobnoj temperaturi) na sorpciona svojstva tkanina jute tretiranih alginatom. Nezavisno od metode ispitivanja (centrifugiranjem ili apsorpcijom vode posle potapanja), dobijen je isti trend poboljšanja sposobnosti zadržavanja vode tkanina tretiranih alginatom. Sposobnost zadržavanja vode nesušene tkanine tretirane 2,0% rastvorom natrijum-alginata, određene metodom apsorpcije vode posle potapanja ili centrifugiranjem, povećana je 4,8 ili 3,3 puta u poređenju sa sirovom tkaninom jute, respektivno. Štaviše, tretman tkanina jute 0,5% rastvorom natrijum-alginata dovodi do smanjenja vremena kvašenja sa 206,9±6,6 s na 1,7±0,1 s. Poboljšana sorpciona svojstva tkanina jute tretiranih alginatom pripisuju se sloju alginata na njihovoj površini sa većim brojem dostupnih karboksilnihi hidroksilnih grupa sposobnih da formiraju nove vodonične veze sa molekulima vode

Cyanobacteria in aquatic ecosystems in Serbia: effects on water quality, human health and biodiversity

<div><p>Cyanobacterial blooms and toxins (cyanotoxins) in both natural and controlled waterbodies are of worldwide concern. This paper presents a review of 130 years of research on the biodiversity, occurrence and toxicity of cyanobacteria in waterbodies throughout Serbia, as well as their effects on water quality and human health. Data on the occurrence of particular cyanotoxins over more recent years are also collated. Data from over 70 sources, including research articles, project reports, conference abstracts, dissertations, books, annual and news reports are summarized. This survey provides a valuable resource for current and future assessments of cyanobacterial and cyanotoxin occurrence and abundance in Serbian waterbodies, and for management solutions where ecosystems and human health are jeopardized.</p></div

Adsorpcija Kongo crvenog kao indikatora sorpcionih svojstava oksidisane tkanine od jute

This work aims to obtain jute fabrics with improved sorption properties that could be used as a novel solution for biodegraded land rehabilitation. For that purpose, raw jute fabric was oxidized with 0.4% sodium periodate (NaIO4), while the adsorption of textile dye Congo Red (CR) was used as an indicator for fabrics' sorption properties. The kinetic study revealed that fabric oxidized for 60 min reached equilibrium dye adsorption after 270 min, while in the case of jute oxidized for 120 min, the equilibrium was attained 30 min faster. This behavior is ascribed to the better availability and higher content of functional groups (capable of binding CR) within fabric oxidized for 120 min than within those oxidized for 60 min. The above-mentioned could be also used as an explanation for the 35 and 50% higher adsorption capacities of fabrics oxidized for 60 and 120 min compared to the raw fabric, respectively. With increasing the initial concentration of CR from 25 up to 100 mg L-1, the equilibrium adsorption increased up to 2.6 times.Cilj ovog rada je dobijanje tkanine od jute sa poboljšanim sorpcionim svojstvima koja ce se koristititi za rehabilitaciju degradiranog zemljišta. U tu svrhu, sirova tkanina jute oksidisana je 0,4% rastvora natrijum-perjodata (NaIO4), dok je adsorpcija tekstilne boje Kongo crvenog (CR) korišcena kao indikator sorpcionih svojstava. Kineticka istraživanja pokazala su da je tkanina oksidisana tokom 60 minuta dostigla ravnotežnu adsorpciju boje nakon 270 minuta, dok je u slucaju tkanine od jute oksidisane tokom 120 minuta ravnoteža postignuta 30 minuta brže. Ovakvo ponašanje posledica je bolje dostupnosti i veceg sadržaja funkcionalnih grupa (sposobnih da vežu CR) unutar tkanine oksidisane tokom 120 minuta u odnosu na tkaninu oksidisanu tokom 60 minuta. Navedeno bi se moglo koristiti i kao objašnjenje za 35 i 50% vece adsorpcione kapacitete uzoraka tkanine oksidisanih tokom 60 i 120 minuta u pore enju sa sirovom tkaninom, redosledno . Sa povecanjem pocetne koncentracije CR sa 25 na 100 mg L-1, ravnotežna adsorpcija se povecava do 2,6 puta