Biological activity of surfactins - a case of a biosurfactant produced by Bacillus subtilis PCM 1949.

Biosurfactants are microbial surface active compounds which, contrary to synthetic surfactants, are natural in origin, biodegradable and less toxic to a human organism. For that reason, there is a great research potential in studies aimed at their purification, finding potential ways of their utilization and decreasing their production costs. This paper demonstrates the process of isolating and purifying a surfactin synthesized by Bacillus subtilis PCM 1949. Surfactin samples were prepared by a classical organic solvent extraction and were studied using mass spectrometry (MS). Analysis of the susceptibility profile of microorganisms utilized in the diffusion-plate tests demonstrated that their sensitivity to this surfactin is differentiated and depends on the microorganism species. In our studies, we found that the selected strains of bacteria and fungi were insensitive to this surfactin at a wide range of concentrations.

Alternaria alternata and its allergens: a comprehensive review.

Alternaria alternata is mainly an outdoor fungus whose spores disseminate in warm, dry air, so in temperate climates, their count peaks in the summers. Alternaria may also be found in damp, insufficiently ventilated houses, where its allergenic properties cocreate the sick building syndrome. Mold-induced respiratory allergies and research on Alternaria both have a lengthy history: the first was described as early as 1698 and the second dates back to 1817. However, the two were only linked in 1930 when Alternaria spores were found to cause allergic asthma. The allergenic extracts from Alternaria hyphae and spores still remain in use but are variable and insufficiently standardized as they are often a random mixture of allergenic ingredients and coincidental impurities. In contrast, contemporary biochemistry and molecular biology make it possible to obtain pure allergen molecules. To date, 16 allergens of A. alternata have been isolated, many of which are enzymes: Alt a 4 (disulfide isomerase), Alt a 6 (enolase), Alt a 8 (mannitol dehydrogenase), Alt a 10 (alcohol dehydrogenase), Alt a 13 (glutathione-S-transferase), and Alt a MnSOD (Mn superoxide dismutase). Others have structural and regulatory functions: Alt a 5 and Alt a 12 comprise the structure of large ribosomal subunits and mediate translation, Alt a 3 is a molecular chaperone, Alt a 7 regulates transcription, Alt a NTF2 facilitates protein import into the nucleus, and Alt a TCTP acts like a cytokine. The function of four allergenic proteins, Alt a 1, Alt a 2, Alt a 9, and Alt a 70 kDa, remains unknown.

[Allergens of mites]. / Alergeny roztoczy.

Mite allergens belong to the group of inhalant allergens and represent antigenic substances which are particutlarly important in the pathogenesis of respiratory system diseases and skin diseases. The most common diseases associated with chronic exposure to these aeroallergens include: allergic rhinitis, bronchial asthma and atopic dermatitis. Mite allergens are simple proteins or glycoproteins with different molecular structures and various biochemical functions. The sensitizing capacity of these proteins is connected from their physicochemical properties. Individual allergens perform, among others, the functions of structural proteins, act as enzymes, transport lipids, bind metal ions, and are capable of glycosylation. In addition, mite allergenic proteases degrade proteins of the skin epithelium-resulting in a weakening of its natural protective barrier-and induce the immune response. The proteases also induce the release of pro-inflammatory cytokines: interleukin-4 (IL-4), interleukin 6 (IL-6), interleukin 8 (IL-8), eotaxin, and granulocyte-macrophage colony-stimulating factor-GM-CSF. The article presents the tertiary structure of major and mid-range mite allergens and their classification. Based on literature reports concerning the chemical structure of allergenic proteins, it was emphasized that the structural differences between homologous proteins with allergenic pozoproperties relate to the distribution of amino acid residues on the surface of the molecule. IgE binding affinity and the similarities and differences in the amino acid sequence of the allergens were also the basis for determining cross-reactivity of allergenic proteins. The paper shows an example of this phenomenon, describing the existence of common allergens for various mite species.