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1

Enzymatyczna regeneracja ortofosforanu w wodach jezior

100%
Siuda W.
Postępy Mikrobiologii
|
2001
|
tom 40
|
nr 2
187-217
2

Bialka jako substrat pokarmowy dla mikroorganizmow wodnych

63%
Kiersztyn B., Siuda W.
Postępy Mikrobiologii
|
2007
|
tom 46
|
nr 4
355-366
3

Some factors affecting the heterotrophic activity of becateria in lake

63%
Chrost R. J., Siuda W.
Acta Microbiologica Polonica
|
1978
|
tom 27
|
nr 2
4

Urea in lake ecosystem: the origin, concentration and distribution in relation to trophic state of The Great Mazurian Lakes (Poland)

63%
Siuda W., Kiersztyn B.
Polish Journal of Ecology
|
2015
|
tom 63
|
nr 1
The distribution, concentrations and origin of urea were studied in surface and profundal waters of meso-eutrophic and highly eutrophic parts of The Great Mazurian Lake System (GMLS) during spring — autumn period. Urea concentrations varied from 0.25 µM in surface layer to 3.36 µM in profundal zone of studied lakes and were in the range of concentrations noted in other non-polluted freshwater habitats. In the photic zone of lakes of GMLS Urea N made up to 10 % the total DON pool and often exceeded 2-3 times of NH₄-N concentrations. Pattern of changes in urea concentrations observed during three-years study excludes external urea input and suggests supplementation of lake waters with this compounds by phytoplankton decomposition processes. Generally, urea concentrations were negatively correlated with the trophic state index calculated from “algal” as well as from “bacterial” determinants. However, more detailed analysis showed that the relationships between production and assimilation of urea by various plankton components as well as the ecological role of this compound in meso- and eutrophic lakes could be different.
5

The relationship between alkaline phosphatase (APA) activity and phosphate availability for phytoplankton and bacteria in eutrophic lakes

63%
Siuda W., Chrost R. J.
Acta Microbiologica Polonica
|
1987
|
tom 36
|
nr 3
6

Czy oczyszczalnie ścieków zagrażają jakości wód Wielkich Jezior Mazurskich?

63%
Siuda W., Chrost R.
Ekonatura
|
2011
|
nr 12
7

The role of phosphorus and organic carbon compounds in regulation of alkaline phosphatase activity and regeneration processes in eutrophic lakes

63%
Siuda W., Gude H.
Polskie Archiwum Hydrobiologii
|
1994
|
tom 41
|
nr 2
171-187
8

Decomposition and utilization of particulate organic matter by bacteria in lakes of different trophic status

63%
Siuda W., Chrost R. J.
Polish Journal of Environmental Studies
|
2002
|
tom 11
|
nr 1
Enzymatic decomposition and bacterial utilization of various types of particulate and dissolved substrates was studied during spring-summer period in four lakes of Mazurian Lake District (Northern Poland). We found that seston particles, similarly as dissolved organic matter (DOM), undergo intensive decomposition processes in lake water, but only after their previous colonization by bacteria. In lakes of low or moderate trophic status free-living microorganisms predominated. They preferentially utilized low molecular weight, dissolved organic compounds. Increases in particulate organic matter (POM) content in these environments caused rapid change of substrate exploitation strategy and adaptation of these bacteria to live in particle-attached forms. In lakes of POM and colloidal DOM (CDOM) abundant particle-attached microheterotrophs, although less metabolically active than free-living bacteria, were mainly responsible for secondary production and POM mineralization A mechanisms that permit effective POM exploitation by seston-attached bacteria was overproduction of relatively low active (high Km) enzymes (e.g. aminopeptidase) and/or synthesis of the enzymes (e.g. β-glucosidase or glucosaminidase) that were optimally adapted (low Km) to the environment.
9

Utilization of selected dissolved organic phosphorus compounds by bacteria in lake water under non-limiting orthophosphate conditions

63%
Siuda W., Chrost R. J.
Polish Journal of Environmental Studies
|
2001
|
tom 10
|
nr 6
This study presents results on the availability of various organic P compounds for bacteria from mesotrophic Lake Constance. The rates of hydrolysis of all tested compounds added to the analyzed lake water samples did not correlate with assimilation of liberated inorganic P. beta -glycerophosphate and AMP were the most efficiently hydrolysed by bacterial phosphohydrolytic enzymes. The highest specific P uptake was found in water samples supplemented with nucleotides. The fastest increase in bacterial numbers was observed in water samples enriched with DNA, RNA, ATP and phytin. Analysis of discrepancies between rates of hydrolysis, specific P uptake and bacterial growth rates in samples enriched with various organic P compounds suggested that bacterial phosphatases participated substantially in processes of dissolved organic carbon (DOC) compound decomposition in lake water, whereas 5'-nucleotidase was mainly responsible for bacterial P demand.
10

Urea and ureolytic activity in lakes of different trophic status

63%
Siuda W., Chrost R. J.
Polish Journal of Microbiology
|
2006
|
tom 55
|
nr 3
Urea and uraease (U-ase) activity were determined in water samples taken from the surface layers of 17 lakes of different trophic status. Urea concentrations were inversely correlated with the trophic status of the studied lakes and varied from below the detection limit to 25 μmol 1⁻¹. Maximal potential ureolytic activity (Vmax) ranged from 0.2 to 7.0 μmol 1⁻¹ h⁻¹. The highest urea concentrations and the lowest U-ase activities were recorded in the spring, whereas the lowest urea concentrations and the highest rates of urea hydrolysis were observed late in summer, during heavy phytoplankton blooms. Since in the majority of the Great Mazurian Lakes microplankton growth was limited by nitrogen supply, urea was an important N source for both auto- and heterotrophic planktonic microorganisms throughout the growth period. U-ase activity was mainly related to the seston. Only up to 25% of total activity could be attributed to free enzymes dissolved in lake water. In epilimnetic water samples the bulk of the ureolytic activity originated from seston-attached bacteria. However, a positive, statistically significant correlation between ureolytic activity and chlorophyll a (Chla) concentrations suggests that phytoplankton may also be responsible for at least a some of the observed ureolytic activity in the highly eutrophic Great Mazurian Lakes.
11

Coomassie blue G250 for visualization of active bacteria from lake environment and culture

51%
Kiersztyn B., Siuda W., Chrost R.
Polish Journal of Microbiology
|
2017
|
tom 66
|
nr 3
Bacteria play a fundamental role in the cycling of nutrients in aquatic environments. A precise distinction between active and inactive bacteria is crucial for the description of this process. We have evaluated the usefulness of Coomassie Blue G250 for fluorescent staining of protein containing potentially highly active bacteria. We found that the G250 solution has excitation and emission properties appropriate for direct epifluorescence microscopy observations. It enables fast and effective fluorescent visualization of living, protein-rich bacteria, both in freshwater environment and culture. Our results revealed that the number of G250-stained bacteria from eutrophic lake was positively correlated with other standard bacterial activity markers, like number of bacteria containing 16S rRNA, bacterial secondary productionor maximal potential leucine-aminopeptidase activity. In case of the E. coli culture, the percentage of bacteria visualized with G250 was similar to that of bacteria which accumulated tetracycline. Compared to other common methods utilizing fluorogenic substances forbacteria staining, the approach we evaluated is inexpensive and less hazardous (for example mutagenic) to the environment and researchers. It can be regarded as an additional or alternative method for protein rich, active bacteria staining.
12

Enzymatic "fingerprinting" of physiological diversity of microbial communities in clear-water and humic lakes

51%
Siuda W., Jasser I., Kiersztyn B.
Polish Journal of Ecology
|
2013
|
tom 61
|
nr 4
Extracellular enzymes occurring in aquatic environment are heterogeneous in respect to their origin and function, place, where they are located and their activity. They can be divided into mainly ‘bacterial-origin’ enzymes produced by heterotrophic organisms in order to obtain organic carbon, and mostly ‘phytoplankton-bacterial-origin’ enzymes, which are produced by autotrophic and heterotrophic organisms, and are responsible mainly for obtaining inorganic compounds. Enzymes activity provides information about microorganisms present in given environment and about their physiological state. We hypothesize that the patterns (‘fingerprints’) calculated on the basis of activity of several enzymes both mainly ‘bacterial-origin’ and mainly ‘phytoplankton-bacterial-origin’ may be used to characterise lake ecosystems in terms of the physiological structure of aquatic microorganisms present in these lakes. For the study we selected four lakes from Mazurian Lakes District in north-eastern Poland. Three of them were clear-water (lakes: Kuc, Mikołajskie, Tałtowisko) and ranged from oligotrophy to eutrophy, the fourth (Lake Smolak Duży) was slightly acidic (pH 5.2), highly productive and polyhumic. Activity of phosphatase (PA), L-leucine-aminopeptidase (AMP), β-glucosidase (B-Glu), esterase (EST), glucosaminidase (Glu-ami), glucuronidase (Glu-uro) and cellobiohydrolase (Cellob) were measured fluorometrically. The results were normalised and analysis of agglomerative clustering was performed to create an enzyme activity patterns characteristic for lakes. We found out that the enzymatic pattern reflected trophic differences between studied lakes. The patterns (‘fingerprints’) of enzymes were similar for three clear-water lakes, with urease (U–ase), AMP and EST dominating the overall enzymatic activity, but differed substantially for polyhumic lake, in which considerably high PA and saccharolytic enzyme activities were observed. We conclude that the analysis of enzymatic ‘fingerprints’ can be a useful tool to characterise lakes with respect to their trophic status and physiological diversity of microbial assemblages associated with each particular lake.
13

Stan zasolenia gleb w okolicy Inowrocławskich Zakładów Sodowych w Mątwach

51%
Ciesla W., Dabkowska-Naskret H., Siuda W.
Roczniki Gleboznawcze
|
1981
|
tom 32
|
nr 2
14

Microbial ectoenzyme activity: useful parameters for characterizing the trophic conditions of lakes

51%
Kiersztyn B., Siuda W., Chrost R. J.
Polish Journal of Environmental Studies
|
2002
|
tom 11
|
nr 4
This report describes the relationship between microbial enzymatic activities (aminopeptidase, esterase, and alkaline phosphatase) and the trophic state index of the studied lakes. Pelagic surface water samples were collected from nineteen lakes (Mazurian Lake District, northeastern Poland), characterized by different degrees of eutrophication, during spring homothermy and summer thermal stratification periods in 1999 and 2000. Aminopeptidase and esterase activities of microbial assemblages in unfiltered water samples were positively proportional to the trophic conditions of the studied lakes and both enzymes significantly correlated with Carlson's trophic state index of lakes. No correlation between alkaline phosphatase activities and the trophic state index of the studied lakes was found. This study showed that the selected parameters of microbial activity are very useful for the rapid determination of actual trophic conditions in lake ecosystems.
15

Bacterial secondary production and bacterial biomass in four Mazurian Lakes of differing trophic status

51%
Chrost R. J., Koton M., Siuda W.
Polish Journal of Environmental Studies
|
2000
|
tom 09
|
nr 4
This report presents results of four-year studies of bacterial production and biomass, and selected environmental variables (concentrations of total DOC, microbiologically labile DOC, chlorophylla) in surface pelagic waters of four Mazurian lakes of differing trophic status (oligo/mesotrophic, eutrophic, hypereutrophic, polihumic) during summer stratification periods 1994-97. Bacterial production and biomass were positively proportional to the degree of lake water eutrophication. The rates of production of bacteria and their biomass turnover were primarily dependent on concentrations of microbiologically labile organic substrates in the DOC pool. In lakes with high content of suspended particulate detritus (hypereutrophic and polihumic lakes) attached bacteria significantly predominated in total bacterial production. Importance of the "bottom-up" and "top-down" mechanisms in ecological regulation of bacterial production and biomass in the studied lakes is widely discussed.
16

The role of planktonic organisms in urea metabolism in lakes of temperate zone – case study

45%
Siuda W., Chrost R. J., Kalinowska K., Ejsmont-Karabin J., Kiersztyn B.
Polish Journal of Ecology
|
2016
|
tom 64
|
nr 4
Although urea is the simplest N-containing organic compound ubiquitous in all aquatic environments, its role in N-nutrition of planktonic biota and relevance for eutrophication of freshwater ecosystems is still insufficiently defined and often bypassed. The dynamics of production of autochthonous urea as well as maximal potential net ureolytic activity (net URA Vmax) of phyto- and bacterioplakton were studied in mesocosm experiment and verified during the field studies conducted in the Great Mazurian Lake system (GMLS). Analysis of the obtained results revealed that the proteins were the main autochthonous urea precursors. Urea concentration in the studied mesocosms and in GMLS surface waters was positively correlated with flagellate, ciliate and crustacean biomass and, less evidently, with bacterial biomass (BB). In surface waters of GMLS net URA Vmax, similarly as urea concentrations, increased with their trophic status. Analysis of correlation of potential ureolytic activity with chlorophyllₐ, (Chlₐ) BB and L-leucine aminopeptidase activity (AMP) in lakes of different trophic status suggests that although both groups of planktonic microorganisms participated in urea decomposition processes, in eutrophic ones bacterial decomposition of urea is more evident. In highly eutrophic lakes excess of phosphorus induced higher nitrogen requirement resulting in the increase in protein decomposition rate. Intensified protein degradation resulted faster urea production, which finally induced higher ureolytic activity of planktonic microorganisms. In profundal waters of GMLS potential ureolytic activity was distinctly lower than in surface waters. This was caused by low temperature of hypolymnetic waters, inhibitory effect of hydrogen sulphide and lack of phytoplankton, which is known as a primary urea consumer.
17

The relationship between primary production and respiration in the photic zone of the Great Mazurian Lakes (GMLS), in relation to trophic conditions, plankton composition and other ecological factors

45%
Siuda W., Kauppinen E. S., Kalinski T., Chrost R. J., Kiersztyn B.
Polish Journal of Ecology
|
2017
|
tom 65
|
nr 3
The relation of primary production to respiration and dependence of both processes on various environmental factors were investigated in the surface waters of lakes of The Great Mazurian Lake System (GMLS) during summer seasons 2009–2011. Primary production and extracellular release was determined by ¹⁴C method, respiration (dark oxygen consumption) - by Winkler's method. Collected results allow to conclude that: (i) in all studied lakes primary production was primarily cyanobacterial, although in mesotrophic ones participation of eukaryotic phytoplankton in light CO₂ fixation was more pronounced; (ii) in mesotrophic part of GMLS primary production was limited alternately by N and P availability and less dependent on N and P regeneration processes, whereas in southern, eutrophic lakes it was primarily fueled by regeneration of biogenic substances from organic compounds and strongly limited by N resources; (iii) although in photic zone of whole GMLS respiration was dominated by heterotrophic bacteria, in its mesotrophic part also participation of other plankton components in respiration processes was significant and, (iv) that in eutrophic lakes planktonic respiration was more dependent on low molecular weight products liberated enzymatically from organic substrates than on organic compounds released by primary producers. The mean production to respiration ratio, which varied from 2.11 to 2.60 in northern, and from 2.05 to 3.67 in southern lakes suggested that during period of investigations photic zones of lakes of both parts of GMLS were net autotrophic systems.
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