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

Elasticity as the basis of allostery in DNA

Allosteric interactions in DNA are crucial for various biological processes. These interactions are quantified by measuring the change in free energy as a function of the distance between the binding sites for two ligands. Here we show that trends in the interaction energy of ligands binding to DNA can be explained within an elastic birod model. The birod model accounts for the deformation of each strand as well as the change in stacking energy due to perturbations in position and orientation of the bases caused by the binding of ligands. The strain fields produced by the ligands decay with distance from the binding site. The interaction energy of two ligands decays exponentially with the distance between them and oscillates with the periodicity of the double helix in quantitative agreement with experimental measurements. The trend in the computed interaction energy is similar to that in the perturbation of groove width produced by the binding of a single ligand which is consistent with molecular simulations. Our analysis provides a new framework to understand allosteric interactions in DNA and can be extended to other rod-like macromolecules whose elasticity plays a role in biological functions

Synteza celulaz w hodowlach bakterii Paenibacillus sp. wyizolowanych z ryzosfery

 gleby ryzosferowej jabłoni, wiśni i truskawki nawożonej kompostami przygotowanymi na bazie miału z węgla brunatnego z dodatkiem grzybni Basidiomycota, wyizolowano sześć szczepów bakterii względnie beztlenowych, przetrwalnikujących zdolnych do rozkładu celulozy. Na podstawie morfologii, cech biochemicznych i sekwencji 16S rRNA izolaty sklasyfikowano do gatunków z rodzaju Paenibacillus. W pożywkach wybiórczych z dodatkiem bibuły filtracyjnej (FP) i karboksymetylocelulozy (CMC) badane izolaty syntetyzowały enzymy, które hydrolizują celulozę amorficzną i krystaliczną. Badane izolaty w 14 i 28-dniowych hodowlach w pożywce z karboksymetylocelulzą (CMC) produkowały odpowiednio od 0 mU do 10,87 mU oraz od 10,73 do 21,13 mU CMCazy (karboksymetylocelulazy). Najwyższą aktywność enzymów scukrzających celulozę (FPazy) w pożywce z CMC wykazano w 14-dniowych hodowlach P. lautus EG_11 – 75,6 mU, Paenibacillus sp. EG_17 – 57,6 mU oraz P. woosongensis EG_15 – 38,9 mU. W pożywce z dodatkiem bibuły filtracyjnej (FP), najwyższą produkcję CMCazy i FPazy odnotowano w hodowlach P. lautus EG_11 – odpowiednio 79,85 i 118,83 mU

Endocrine Disrupting Compounds (Nonylphenol and Bisphenol A)–Sources, Harmfulness and Laccase-Assisted Degradation in the Aquatic Environment

Environmental pollution with organic substances has become one of the world’s major problems. Although pollutants occur in the environment at concentrations ranging from nanograms to micrograms per liter, they can have a detrimental effect on species inhabiting aquatic environments. Endocrine disrupting compounds (EDCs) are a particularly dangerous group because they have estrogenic activity. Among EDCs, the alkylphenols commonly used in households deserve attention, from where they go to sewage treatment plants, and then to water reservoirs. New methods of wastewater treatment and removal of high concentrations of xenoestrogens from the aquatic environment are still being searched for. One promising approach is bioremediation, which uses living organisms such as fungi, bacteria, and plants to produce enzymes capable of breaking down organic pollutants. These enzymes include laccase, produced by white rot fungi. The ability of laccase to directly oxidize phenols and other aromatic compounds has become the focus of attention of researchers from around the world. Recent studies show the enormous potential of laccase application in processes such as detoxification and biodegradation of pollutants in natural and industrial wastes

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

The role of exochitinase type A1 in the fungistatic activity of the rhizosphere bacterium Paenibacillus sp. M4

The aim of the study was to detect the activity and characterize potentially fungistatic chitinases synthesized by rhizosphere bacteria identified as Paenibacillus sp. M4. Maximum chitinolytic activity was achieved on the fifth day of culturing bacteria in a growth medium with 1% colloidal chitin. Analysis of a zymogram uncovered the presence of four activity bands in the crude bacterial extract. The used three-stage protein purification procedure resulted in a single band of chitinase activity on the zymogram. The purified enzyme exhibited maximum activity at pH 6.5 and temperature 45oC, and thermal stability at 40oC for 4 h. In terms of substrate specificity, it is an exochitinase (chitobiose). The amino acid sequence obtained after mass spectrometry showed similarity to chitinase A1 synthesized by Bacillus circulans. The M4 isolate demonstrated the highest growth inhibiting activity against plant pathogens belonging to the genera Fusarium, Rhizoctonia and Alternaria. Fungistatic activity, although to a somewhat lesser degree, was also demonstrated by purified chitinase. The obtained results confirm the participation of the studied exochitinase in antagonism towards pathogenic molds. However, the lower fungistatic effectiveness of the chitinases points to the synergistic action of different metabolites in biocontrol by these bacteria

Biochemical Characteristics of Laccases and Their Practical Application in the Removal of Xenobiotics from Water

The rapid growth of the human population in recent decades has resulted in the intensive development of various industries, the development of urban agglomerations and increased production of medicines for animals and humans, plant protection products and fertilizers on an unprecedented scale. Intensive agriculture, expanding urban areas and newly established industrial plants release huge amounts of pollutants into the environment, which, in nature, are very slowly degraded or not decomposed, which leads to their accumulation in water and terrestrial ecosystems. Researchers are scouring extremely contaminated environments to identify organisms that have the ability to degrade resistant xenobiotics, such as PAHs, some pharmaceuticals, plasticizers and dyes. These organisms are a potential source of enzymes that could be used in the bioremediation of industrial and municipal wastewater. Great hopes are pinned on oxidoreductases, including laccase, called by some a green biocatalyst because the end product of the oxidation of a wide range of substrates by this enzyme is water and other compounds, most often including dimers, trimers and polymers. Laccase immobilization techniques and their use in systems together with adsorption or separation have found application in the enzymatic bioremediation of wastewater

New aspects of the enzymatic breakdown of chitin: a review

This review focuses on the enzymatic breakdown of chitin, taking into account the latest scientific reports on the activity of lytic polysaccharide monooxygenase (LPMO). Chitin is a natural, abundant polysaccharide of great practical importance in the environment. However, the insolubility in water and the tightly packed crystalline structure of chitin pose a serious obstacle to enzymatic degradation. This substrate can be converted into soluble sugars by the action of glycosidic hydrolases (GH), also known as chitinases. LPMO could prove to be helpful in enzymatic processes that increase the rate of chitin depolymerisation by improving the availability of substrates for chitinases. The unique action of LPMO is based on the ability to catalyse the oxidative cleavage of glycosidic chains present in complex, resistant crystal networks of chitin, and this cleavage facilitates the subsequent action of glycolytic hydrolases