The ability of six strains belonging to the genus Pseudomonas isolated from the rhizosphere of wheat to produce pyoverdin was examined. The studied strains demonstrated a varied level of production of the siderophore, depending on the culture conditions. The highest level of pyoverdin was determined after 72 hours of growth at 20-25°C in iron-free medium supplemented with succinate. The synthesis of pyoverdin by all the strains studied was strongly repressed by the addition of iron ions (III) to the growth medium. Calcium, cadmium and magnesium ions stimulated the synthesis of the siderophore examined, whereas zinc and lead ions partially decreased its level. Enrichment of the growth medium in cobalt ions completely inhibited the synthesis of siderophores as well as growth of the bacteria.
Sposób zagospodarowania zlewni wpływa na warunki siedliskowe ekosystemu wodnego. Poprzez analizę jakościową wód rzeki można określić przypuszczalne źródło jej zanieczyszczenia, a tym samym zdefi niować sposób użytkowania terenu. W wodach górnego odcinka rzeki Narwi analizowano liczebność Escherichia coli. Wyniki zestawiono z poziomem wybranych wskaźników jakości chemicznej wody oraz danymi hydromorfologicznymi. Uzyskane dane dowodzą, że sposób użytkowania zlewni wpływa znacząco także na zanieczyszczenie fekalne rzeki. Jego źródłem są procesy naturalne i antropogeniczne. Istotną przyczyną zanieczyszczenia bakteriologicznego rzeki jest zrzut z lokalnych oczyszczalni ścieków. W okresie wiosennym wzrost liczebności E. coli do ponad 2400 NPL/100 cm3 wynika z licznego występowania ptactwa wodnego na obszarze Narwiańskiego Parku Narodowego. Latem wzrost liczebności E. coli związany jest ze spływem z terenu sąsiadujących z rzeką gospodarstw i licznych pastwisk bydła mlecznego.
The bacterium Stenotrophomonas maltophilia N4 produces different extracellular proteases when cultured in a mineral medium with 1% of bird feathers. One of the enzymes was purified and characterized. The studied enzyme is a peptidase with keratinolytic activity. The optimal temperature for enzyme activity of the purified protein is 60°C, and its pH optimum 8.5. Its thermal stability is approximately 50% after two hours of preincubation at 55°C. Enzymatic activity is strongly inhibited by DFP and EDTA, indicating that the enzyme belongs to the metal-dependent serine proteases. Calcium, magnesium and manganese ions enhance the activity of the studied keratinase. The enzyme has broad substrate specificity; it hydrolyzes not only keratin, but also casein, gelatin and hemoglobin Considering the fact that the N4 bacteria are capable of using bird feathers as a source of organic nitrogen and carbon, and bearing in mind the stability and the broad substrate specificity of the studied enzyme, it appears that it may find application in various branches of biotechnology.
Studies on the microbiological quality of selected watercourses in the Białowieski Primeval Forest were assumed (Narewka, Orłówka, Hwoźna, Braszcza, Łutownia, Przedzielnia). ln samples of water taken in the years 2010-2015, the numbers of psychrophilic, coliform and Escherichia coli were determined. High organic contamination of all of the studied watercourses, typical of woodland and wetland areas, was confirmed. lncreased microbiological contamination was indicated only for the Orłówka and Braszcza rivers, which suggests an inflow of contaminants from areas inhabited by wild animals and water-logged areas. The poor sanitary quality of waters from the Hwoźna River is most likely connected with the cross-border inflow of contaminants.
An intracellular aminopeptidase N synthesized by Pseudomonas putida Lup was purified and characterized. The approx. 150-fold purified enzyme showed highest activity against A-β-naphthylamide at pH 7.5 and at temperature 40°C and was 100% thermostable for 240 min at 40°C. P. putida lup aminopeptidase N is a monomer with molecular mass approx. 99 kDa determined by SDS-PAGE and gel permeation chromatography. The enzyme has broad substrate specificity, but is the most active against protein substrates with N-terminal alanine and arginine. The activity of P. putida Lup aminopeptidase N is strongly inhibited in the presence of specific metallopeptidase inhibitors and is partly recovered in the presence of Zn²⁺ and Co²⁺ ions. Co²⁺, Mg²⁺ and Ca²⁺ ions increased the activity of the enzyme. Moreover, the enzyme was inhibited by inhibitors of cysteine enzymes. Analysis of fragments of the amino acid sequence of the purified enzyme demonstrated high similarity to PepN of Pseudomonas putida GB-1.