Ecological analysis of macrozoobenthos communities in the Nišava River

Doktorska disertacija obuhvata ekološku analizu zajednica makrozoobentosa reke Nišave i njihovu zavisnost od biotičkih i abiotičkih faktora. Istraživanja su obavljena mesečnom dinamikom na dvanaest lokaliteta od maja 2006. do aprila 2007. godine. U disertaciji se diskutuje zavisnost koncentracije hlorofila a i mase perifitona od abiotičkih faktora. Sa druge strane, razmatran je pritisak (na osnovu brojnosti) filtratornih vrsta zajednice makroinvertebrata na količinu fitoplanktona (izraženu preko hlorofila a) i pritisak grebača na masu perifitona. Dobijen je predikcioni model za izračunavanje koncentracije hlorofila a korišćenjem multiple linearne regresije. Model ima značajnu predikcionu moć (sig=0,003). Na osnovu Pirsonovog koeficijenta korelacije konstatovano je da postoji značajna povezanost koncentracije hlorofila a sa mutnoćom (p=0,000), sa ukupnim fosforom (p=0,029) i sa kombinovanom (zbirnom) koncentracijom ukupnog azota i fosfora (p=0,036). Nije utvrđena značajna povezanost sa brojnošću filtratornih organizama, što govori da njihov pritisak nije dovoljno jak da bi limitirao količinu fitoplanktona. Taksonomskom analizom makroinvertebrata reke Nišave utvrđeno je prisustvo 132 vrste iz 4 različita filuma. Filum Platyhelminthes je predstavljen sa 3 vrste iz 2 familije. Filum Annelida obuhvata 23 vrste iz 6 familija. Najveći broj vrsta ovog filuma pripada potklasi Oligochaeta (16 vrsta). Filum Mollusca obuhvata 13 vrsta iz 5 familija, od kojih 11 pripada klasi Gastropoda, a 2 klasi Bivalvia. Najveći broj vrsta faune makroinvertebrata pripada filumu Arthropoda (92 vrste iz 33 familije), od kojih 3 pripadaju subfilumu Crustacea, a sve ostale podfilumu Hexapoda, odnosno klasi Insecta. Rezultati taksonomske analize pojedinačnih grupa u okviru zajednice makroinvertebrata pokazuju da najveći broj vrsta pripada grupi Ephemeroptera (28 vrsta), zatim slede Diptera (26 vrsta) i Trichoptera (20 vrsta). Ostale grupe su zastupljene sa manjim brojem vrsta. Diskutovana je sezonska i longitudinalna dinamika grupa makroinvertebrata i njihova uslovljenost faktorima sredine. Razmatrani su indeksi diverziteta i adekvatnost njihovog korišćenja kao pokazatelja zagađenosti ekosistema, posebno za svaku grupu...This doctoral dissertation comprises the ecological analysis of macrozoobenthos communities in the Nišava River and their dependence on biotic and abiotic factors. The studies followed the monthly dynamics at 12 sites, from May 2006 to April 2007. The dissertation is discussing the dependence of chlorophyll a concentration and periphyton mass on abiotic factors, as well as the pressure (based on abundance) of filtrating species in the macroinvertebrate community on the amount of phytoplankton (expressed as chlorophyll a) and pressure of scraper species on periphyton mass. The prediction model for calculating chlorophyll a concentration was derived from the multiple linear regression. This model has a significant prediction power (sig=0.003). The Pearson's correlation coefficient was used to determine the correlation of chlorophyll a concentration with water turbidity (p=0.000), total phosphorus (p=0.029) and combined (summative) concentration of total nitrogen and total phosphorus (p=0.036). No significant connection with the abundance of filtrating organisms was determined, which indicates that their pressure was not strong enough to limit the quantity of phytoplankton. The taxonomic analysis of macroinvertebrates in the Nišava River yielded the presence of 132 species from 4 different phyla. The phylum Platyhelminthes was represented with 3 species from 2 families. The phylum Annelida was represented with 23 species from 6 families. Most recorded species from this phylum belong to the subclass Oligochaeta (16 species). The phylum Mollusca was represented with 13 species from 5 families, of which 11 were from the class Gastropoda and 2 from the class Bivalvia. Most species of the macroinvertebrate fauna belong to the phylum Arthropoda (92 species from 33 families), of which 3 were from the subphylum Crustacea, while all others belong to the subphylum Hexapoda and class Insecta. The results of the taxonomic analysis of individual groups within the macroinvertebrate community have shown that most species belong to the group Ephemeroptera (28 species), followed by Diptera (26 species), and Trichoptera (20 species). Other groups were represented with a smaller number of species. The study also includes the discussion on seasonal and longitudinal dynamics of macroinvertebrate groups and the effect of environmental factors on their presence. The diversity indices and their suitability as indicators of ecosystem pollution were discussed for each group separately..

Mechanism of complex formation between [AuCl4] – and L-methionine

The kinetics of the reaction between tetrachloroaurate(III) ion and L-methionine has been studied spectrophotometrically by using stopped-flow technique in 0.1 M HClO4 as the function of temperature. The fast reaction was ascribed to the formation of short living square-planar [AuCl2Met]+ complex ion, that was reduced in the slower reaction step. The activation parameters (∆H≠ and ∆S≠ ) for complex formation were determined. The entropy of activation was compatible with an associative reaction mechanismPhysical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200

Application of ultra performance liquid chromatography (uplc) for determination of Na+ /K+ atpase activity

An ion-pair ultra performance liquid chromatography (IP-UPLC) method was developed to obtain a sensitive and efficient means for quantification of ADP in order to follow the decrease of Na+ /K+ ATPase activity after its exposure to different inhibitors. The concentrations of ADP obtained after hydrolysis of ATP in the presence of enzyme depends on enzyme activity. Simultaneously with the chromatographic determination of ADP, the spectrophotometric determination of phosphates liberated after the hydrolysis of ATP was done.Physical chemistry 2008 : 9th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 200

Spectrophotometric and uplc study of reaction between [AuCl4] - and quercetin

The equilibrium and kinetics of the reaction between tetrachloroaurate(III) ion (AuCl4 - ) and quercetin in 0.1 M HClO4 were studied spectrophotometrically. The fast and the slow reaction steps were distinguished in the reaction mechanism, depending on the ratio of AuCl4 - and quercetin concentration. The stoichiometry of reaction, determined by molar ratio and Jobb’s methods, was 1:1. The kinetics of complex formation was followed under the pseudo-first order conditions by measuring the absorbance at 294 nm vs. time as the function of quercetin concentration in 5 – 15 fold excess.Physical chemistry 2008 : 9th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 200

Thermal Induced Phase Transformation of Cs-Exchanged LTA framework zeolite

Cesium aluminosilicate phases are of great interest as possible hosts for 137Cs immobilization in radioactive waste management. Cs+ exchanged forms of two synthetic zeolites (4A and 3A) were prepared by standard procedure, and content of exchanged ions was determined by ion chromatography. Obtained samples were investigated by differential thermal gravimetry TG/(DTG) and SEM/EDS analysis. All samples were annealed in the range of 600–1500 °C. High temperature phase transformations of Cs+ exchanged zeolites (LTA) were investigated. Based on data obtained by XRD analysis of the samples, it was concluded that above 1000 °C Cs-LTA (4A and 3A) frameworks recrystallized in a pollucite phase

The influence of environmental factors on the structure of caddisfly (Trichoptera) assemblage in the Nisava River (Central Balkan Peninsula)

Monthly samples of caddisfly (Trichoptera) larvae were taken from ten localities along a 151 km long section of the Nisava River (eastern Serbia) during a one year study, with the aim to assessing the spatial composition of the caddisfly assemblage along the river gradient, to identify key environmental factors influencing its variability, to find out if caddisflies are suitable as biological indicators of water quality in this region, and to asses if the caddisfly assemblage in the river follows the river continuum concept. Twenty-three morphologically distinct taxa belonging to 14 genera were identified. The dominant family was Hydropsychidae with 70.34% of specimens examined, followed by Brachycentridae with 9.74% specimens. The longitudinal variability of the caddisfly assemblage has shown a clear dependence on physical and chemical parameters. The CCA analysis suggests that BOD5 and concentration of total phosphorus are the most important factors in structuring the caddisfly assemblage. The species diversity was greatest at localities with the highest oxygen concentration and low nutrient levels. The caddisfly assemblage proved to be useful in identifying differences in environmental conditions in the Central Balkan region.Ministry of Education, Science and Technological Development of the Republic of Serbia [173045, 173030

Mechanism of complex formation between [AuCl4](-) and L-methionine

The kinetics of the reaction between the tetrachloroaurate(III) ion and L-methionine (L-Met) (0.1 M HClO4, pH 1.0-2.5) have been studied spectrophotometrically using a stopped-flow technique at different temperatures. Initially, the fast substitution reaction was ascribed to the formation of the short-lived square-planar Au(III)-(L-Met) that was followed by the replacement of a Cl- ligand and a subsequent, slower reduction to Au(I)-(L-Met). This is an intermolecular process, involving attack on the [AuCl4](-) Complex by an outer-sphere L-methionine. The activation parameters (Delta H-not equal and Delta S-not equal) for substitution and reduction were determined. IR spectroscopy indicates that L-methionine acts as a bidentate ligand, most likely coordinating via the S and N atoms, while H-1 and C-13 NMR data indicate methionine sulfoxide as the final product. Finally, the components of the reaction were treated thermally in order to investigate the solid phase synthesis of the resulting complex. (C) 2008 Elsevier Ltd. All rights reserved

Na+/K+-ATPase: Activity and inhibition

The aim of the study was to give an overview of the mechanism of inhibition of Na+/K+-ATPase activity induced by some specific and non specific inhibitors. For this purpose, the effects of some ouabain like compounds (digoxin, gitoxin), noble metals complexes ([PtCl2DMSO2], [AuCl4](-), [PdCl4](2-), [PdCl(dien)](+), [PdCl(Me(4)dien)](+)), transition metal ions (Cu2+, Zn2+, Fe2+, Co2+), and heavy metal ions (Hg2+, Pb2+, Cd2+) on the activity of Na+/K+-ATPase from rat synaptic plasma membranes (SPM), porcine cerebral cortex and human erythrocytes were discussed.9th International Conference on Fundamental and Applied Aspects of Physical Chemistry, Sep 24-26, 2008, Belgrade, Serbi

The influence of environmental factors on the structure of caddisfly (Trichoptera) assemblage in the Nisava River (Central Balkan Peninsula)

Monthly samples of caddisfly (Trichoptera) larvae were taken from ten localities along a 151 km long section of the Nisava River (eastern Serbia) during a one year study, with the aim to assessing the spatial composition of the caddisfly assemblage along the river gradient, to identify key environmental factors influencing its variability, to find out if caddisflies are suitable as biological indicators of water quality in this region, and to asses if the caddisfly assemblage in the river follows the river continuum concept. Twenty-three morphologically distinct taxa belonging to 14 genera were identified. The dominant family was Hydropsychidae with 70.34% of specimens examined, followed by Brachycentridae with 9.74% specimens. The longitudinal variability of the caddisfly assemblage has shown a clear dependence on physical and chemical parameters. The CCA analysis suggests that BOD5 and concentration of total phosphorus are the most important factors in structuring the caddisfly assemblage. The species diversity was greatest at localities with the highest oxygen concentration and low nutrient levels. The caddisfly assemblage proved to be useful in identifying differences in environmental conditions in the Central Balkan region.Ministry of Education, Science and Technological Development of the Republic of Serbia [173045, 173030