Identification and properties of a keratinase from Stenotrophomonas maltophilia N4 with potential application in biotechnology

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

Temperature Effects Explain Continental Scale Distribution of Cyanobacterial Toxins

Insight into how environmental change determines the production and distribution of cyanobacterial toxins is necessary for risk assessment. Management guidelines currently focus on hepatotoxins (microcystins). Increasing attention is given to other classes, such as neurotoxins (e.g., anatoxin-a) and cytotoxins (e.g., cylindrospermopsin) due to their potency. Most studies examine the relationship between individual toxin variants and environmental factors, such as nutrients, temperature and light. In summer 2015, we collected samples across Europe to investigate the effect of nutrient and temperature gradients on the variability of toxin production at a continental scale. Direct and indirect effects of temperature were the main drivers of the spatial distribution in the toxins produced by the cyanobacterial community, the toxin concentrations and toxin quota. Generalized linear models showed that a Toxin Diversity Index (TDI) increased with latitude, while it decreased with water stability. Increases in TDI were explained through a significant increase in toxin variants such as MC-YR, anatoxin and cylindrospermopsin, accompanied by a decreasing presence of MC-LR. While global warming continues, the direct and indirect effects of increased lake temperatures will drive changes in the distribution of cyanobacterial toxins in Europe, potentially promoting selection of a few highly toxic species or strains.Peer reviewe

Can waters from woodland areas be of poor quality? The problem of sanitary contamination of Białowieża Primeval Forest watercourses

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

Agricultural Rivers at Risk: Dredging Results in a Loss of Macroinvertebrates. Preliminary Observations from the Narew Catchment, Poland

Ecosystem deterioration in small lowland agricultural rivers that results from river dredging entails a significant threat to the appropriate ecohydrological conditions of these water bodies, expressed as homogenization of habitats and loss of biodiversity. Our study was aimed at a comparison of abundance and taxonomic structure of bottom-dwelling macroinvertebrates in dredged and non-dredged stretches of small lowland rivers and tributaries of the middle Narew River, namely: Czaplinianka, Turośnianka, Dąb, and Ślina. The experimental setup was (1) to collect samples of the bottom material from the river stretches that either persisted in a non-modified state (dredging was not done there in the last few years) or had been subjected to river dredging in the year of sampling; and (2) to analyze the abundance and taxonomic structure of macroinvertebrates in the collected samples. The study revealed that at the high level of statistical significance (from p = 0.025 to p = 0.001), the total abundance of riverbed macroinvertebrates in the dredged stretches of the rivers analyzed was approximately 70% lower than in non-dredged areas. We state that the dredging of small rivers in agricultural landscapes seriously affects their ecological status by negatively influencing the concentrations and species richness of benthic macroinvertebrates

Microbiological Tests of air Quality in Var Cabins – Preliminary Tests

The aim of this study is to determine the concentration of fungi and bacteria in the air inside the car cabin and, on this basis, to determine the air quality in the passenger car cabin. The aim of the work is also to demonstrate the impact of hygienic maintenance of filtering devices on the quality of indoor air. The subjects of the research are car cabins, as an example of small, enclosed spaces in which people may remain. The tests were carried out in the summer of 2020 in three passenger cars. Based on the conducted research, it was found that the operation time of regularly serviced air conditioning has a positive effect on the air quality in small, confined spaces. The vehicle with the longest-used filter was characterised by the highest concentration of fungi (8369 CFU/m3) and bacteria (16563 CFU/m3) in the environment inside the car cabin, which means that periodic replacement of the filters in the car's ventilation system is very important. In Poland, it is recommended that such a filter be replaced after a year or after driving 10,000–15,000 kilometres. In analysing the state of air quality in the examined confined spaces, it can be concluded that by ensuring regular replacement of cabin filters and air conditioning servicing, we have a very large impact on indoor air quality

Long-term water quality monitoring using Sentinel-2 data, Głuszyńskie Lake case study

This study shows the results of long-term inland water monitoring using Sentinel-2 data for Głuszyńskie Lake in the years 2015–2022. Four water quality parameters: biological oxygen demand (BOD), dissolved organic carbon (DOC), chlorophyll concentration (CHL) and electrical conductivity (EC) were calculated according to formulas found in the literature. The results were validated based on measurements conducted in 2021 and 2022, where for BOD, DOC and CHL high determination coefficients (0.77 and 0.79) were observed, and the EC determination coefficient was equal to 0.45. The results show that empirical formulas can be used for qualitative analyses of inland water quality, while for quantitative analyses more extensive field work needs to be performed

Assessment of the state of water quality of the Dzierzgoń Lake using chemical and biological indicators

The paper presents an assessment of the state of water pollution of the Dzierzgoń Lake based on bacteriological indicators. Water samples were taken at two measurement points in four study periods in July and August 2011 and 2012. A total number of psychrophilic bacteria and MPN of faecal coliforms were determined. In addition, selected chemical parameters of water quality were analyzed, including total organic carbon and total nitrogen. The results were compared with those obtained by the Provincial Inspectorate for Environmental Protection in 1998 and 2004, and by Rychlik in 2009. It can be concluded that the sanitary condition of the Dzierzgoń Lake is satisfactory.W artykule zbadano stan zanieczyszczenia wód jeziora Dzierzgoń na podstawie wskaźników bakteriologicznych. Pobrano próbki wody w dwóch punktach pomiarowych w czterech terminach badawczych, tj. w lipcu i sierpniu w latach 2011 i 2012. Oznaczono ogólną liczbę bakterii psychrofilnych oraz NPL bakterii coli typu kałowego. Ponadto zanalizowano wybrane wskaźniki chemicznej jakości wody, m.in. ogólną zawartość węgla organicznego, azotu całkowitego i fosforu fosforanowego. Uzyskane wyniki porównano z wynikami uzyskanymi przez WIOŚ w latach 1998 i 2004, oraz wynikami badań uzyskanymi przez Rychlik w 2009 roku. Można stwierdzić, że stan sanitarny jeziora jest zadawalający