Volumen 59 (2020): Edición 1 (January 2020)

After the success of the Human Genome Project, which lead to estimating the number of human genes at only about 30–40 thousand, researchers started paying attention to a great number of genes present inside and on the surface of the human body. The gastrointestinal tract alone is a habitat for up to 1000 species of bacteria and other microorganisms. These microorganisms add a pool of 2–4 million additional genes. In 2009, a hypothesis was proposed that changes in microbiota are sensed by neurons localized along the entire bowel length, and communicated to the brain, making up the gut-brain axis. The vagus nerve seems to serve as the main communication path. Besides affecting gastrointestinal tract functions, primary neuropsychological studies show that gut microbiota is linked to HPA activity, and thus with arousal regulation and emotional functions. Research also suggests a link to cognitive functions. For now, mechanisms of those connections remain, for the most part, unknown. History of the research on human microbiota shows a complex nature of human functions and the need for integration of knowledge from, as it may seem, distant branches of science, like microbiology and psychology. While connections between microbiota and host organism remain unrecognized, our knowledge of human biology will be incomplete.

1. Human Genome Project. 2. In search for the missing genes. 3. Human Microbiome Project. 4. In search for the structure in infinity. 5. Gut-brain axis, towards neuropsychology. 6. Conclusions

Bordetella pertussis is an etiological factor of whooping cough. Despite global vaccination programs, this disease remains endemic in many countries and is still recognized as a significant public health problem. It is estimated that in 2014, around 24 million people worldwide contracted pertussis, of whom 160,700 children under the age of 5 died. Two types of pertussis vaccines are available: suspensions based on whole, killed, B. pertussis cells and acellular pertussis vaccines containing highly purified bacterial antigens. Due to concerns of potential neurological side effects of the whole-cell vaccines, less reactogenic acellular vaccines are now more commonly used. In recent years, many developed countries have reported a resurgence of pertussis disease despite of the high vaccine coverage. Several causes have been suggested for the re-emergence of pertussis including waning immunity and bacterial adaptation resulting from the selection pressure of the used vaccinations.

1. Introduction. 2. Virulence factors of Bordetella pertussis. 3. Pathogenesis of pertussis infection. 4. Clinical symptoms of pertussis. 5. Epidemiology. 6. Genetic variation in Bordetella pertussis. 7. Whole-cell pertussis vaccines. 8. Acellular pertussis vaccines. 9. Future pertussis vaccines. 10. Summary

The most frequent etiologic agents of the urinary tract infections (UTIs) are UPEC strains (Uropathogenic Escherichia coli), which are responsible for 75–95% of UTIs. The virulence factors of UPEC bacteria, as well as their ability to form biofilm, play a significant role in the pathogenicity of UTIs. Limiting iron availability is a major host defense against the growth of microorganisms within hosts. That is why UPEC strains produce various types of siderophores as well as siderophore receptors, which facilitate the uptake and transport of iron to the bacterial cell. Moreover, in order to modulate an inflammatory response and host signaling pathways, UPEC strains produce the following toxins: α-hemolysin (HlyA), cytotoxic necrotizing factor 1 (CNF-1) and vacuolating autotransporter toxin (VAT, Vat-like/ Vat-ExEc). Moreover, Usp is a novel genotoxin of UPEC strains which provokes DNA fragmentation and cell apoptosis. Furthermore, the presence of protein Ag43 enhances adhesion of UPEC within the urinary tract, aggregation and biofilm formation. It is important to underline that all of the virulence factors mentioned above and the ability to form biofilm facilitate and enable UPEC colonization and dissemination in the urinary tract. In conclusion, UPEC harbors an arsenal of virulence factors which promote persistence within the adverse settings of the host urinary tract and finally lead to the development of UTI.

1. Introduction. 2. Iron acquisition system – siderophores, siderophore receptors. 3. Toxins. 3.1. α-hemolysin HlyA. 3.2. Cytotoxic necrotizing factor 1. 3.3. Toxin Vat. 4. Protein Usp. 5. Protein Ag43. 6. Bacterial biofilm. 7. Summary

Probiotics are organisms which belong to the fungi or bacteria groups and affect e.g., bacterial flora in the intestinum or inflammation site by reduction of the condition. They are applied in many cases, such as food allergies, diarrhea, autoimmunologic disorders, and irritable bowel syndrome (IBS) that affects 10% of the world population. Due to the lack of proper pharmacological treatment which would result in complete remission, probiotic preparations which lead to a reduction of the symptoms are one of the most often used drugs. Among them, Saccharomycces cerevisiae var. boulardii has a high efficacy of IBS treatment. There are three main mechanisms of action of this probiotic: antimicrobial activity (direct or anti-toxin), trophic activity, and anti-inflammatory activity.

1. Introduction. 2. Irritable bowel syndrome. 3. History. 4. Morphology. 5. Mechanism of action. 5.1. Luminal action. 5.2. Trophic action. 5.3. Anti-inflammatory action. 6. Taxonomy. 7. Probiotics. 8. Summary

The resistance of bacteria to antimicrobial substances is one of the most serious epidemiological problems present on a global scale. The widespread use of same classes of antimicrobials in human and veterinary medicine, often without laboratory confirmation of the efficacy of active compounds used, contributes to the selection of resistant bacteria in humans and animals, and their spread in nature. The increasing resistance of pathogenic bacteria leads to serious consequences for both human and animal health. However, the resistance of commensal bacteria is equally important as they constitute a reservoir and vector of resistance determinants in the environment. Exposure to antimicrobials belonging to different classes can lead to cross-resistance and the selection of genes that may spread horizontally on mobile genetic elements. The emergence of plasmid-encoded resistance to critically important antibiotics for human medicine e.g. carbapenems or polymyxins is alarming. On the example of antibiotics classified as critically important for human medicine, it is possible to discuss almost all bacterial mechanisms of antimicrobial resistance. For effective combat against the growing antibiotic resistance of bacteria, it is necessary to know the mechanisms of resistance and the methods of their acquisition by bacteria. The aim of the paper is to review the ways that critically important antimicrobials act on bacterial cells and present complex mechanisms that are responsible for resistance to these substances as well as genes conferring for resistance.

1. Introduction. 2. Antimicrobials that cause loss of cell wall integrity: β-lactams, glycopeptides and phosphonic acid derivatives. 2.1. Mechanisms of antimicrobial action. 2.2. Mechanisms of resistance. 3. Antimicrobials affecting the cell membrane: polymyxins and lipopeptides. 3.1. Mechanisms of antimicrobial action. 3.2. Mechanisms of resistance. 4. Antimicrobial substances that inhibit the synthesis of nucleic acids: quinolones and ansamycins. 4.1. Mechanisms of antimicrobial action. 4.2. Mechanisms of resistance. 5. Antimicrobial substances inhibiting protein synthesis: macrolides, ketolides, aminoglycosides, glycylcyclines, oxazolidinones. 5.1. Mechanisms of antimicrobial action. 5.2. Mechanisms of resistance. 6. Summary

Paradoxically, despite the progress in medicine, the prevalence of fungal infections is increasing from year to year. At the beginning of the third millennium, practical therapeutic options are still very limited. Currently, only eight classes of antifungal compounds are in clinical use, only four of which are used in the treatment of dermatomycoses. The intense search for the “Holy Grail” of antifungal therapy that has been going on since the second half of the 20th century faces serious obstacles arising from the eukaryotic model of fungal cell structure. In this paper, new groups of chemical compounds of mainly natural origin have been synthetically described, which due to their interesting antifungal activity, including pathogenic species of dermatophytes, may constitute new therapeutic options. Among compounds currently arousing great interest, compounds from the group of terpenoids, alkaloids, saponins, flavonoids and essential oils deserve attention. Many of these compounds are in clinical trials as potential antifungal agents, while others are in preclinical studies. Future research should focus on attempting to determine the applicability of the given substances in implementation for routine use and their effectiveness, toxicity and side effects.

1. Introduction. 2. General characteristics of dermatophytes in the therapeutic aspect. 3. New synthetic preparations with antifungal activity. 4. Natural antifungal preparations. 4.1. Terpenoids and essential oils. 4.2. Alkaloids. 4.3. Flavonoids. 4.4. Saponins. 4.5. Other chemical compounds 5. Summary

Cellobiose dehydrogenase (CDH) is an extracellular oxidoreductive enzyme produced by wood-decaying fungi belonging to the phylum Basidiomycota and Ascomycota. This enzyme has a binary structure containing two cofactors (FAD and hem), located in separate domains and connected by a proteolytically sensitive linker. Due to its unique structure and properties, CDH has great potential for application in both biotechnology and biomedical applications. The aim of this paper is to review the literature on catalytic properties of cellobiose dehydrogenase and its potential applications.

1. Introduction. 2. Cellobiose dehydrogenase. 2.1. History of discovery and classification of the enzyme. 2.2. Structure, mechanism of action and properties. 3. Application potential of cellobiose dehydrogenase. 3.1. Biomedical applications. 3.2. Application of cellobiose dehydrogenase in biotechnological processes. 4. Summary

The food industry is one area of industrial activities that requires the frequent implementation of technological and product innovations. Foodstuffs obtained both in technologically advanced factories, as well as in small manufacturing enterprises, are increasingly produced using innovative food additives, which include natural polysaccharide ingredients. One of these substances is bionanocellulose – microbially produced cellulose (most commonly by the genus Komagataeibacter xylinus, formerly known as Gluconacetobacter xylinus). Bionanocellulose is a polymer with exceptionally valuable functional properties resulting from its unique molecular structure (formed by the chemically ultra-pure β-1,4-glucan). The main features of bionanocellulose are high hygroscopicity, flexibility and mechanical strength. Various physical and chemical forms of bionanocellulose (produced both during surface and submerged cultivation) are increasingly used in the production of food products. The need to produce highly diversified (e.g., usable or sensory) food products as well as the increasing difficulties associated with access to conventional sources of external coal, necessitate the search of alternative culture media for the production of bionanocellulose. The aim of the work is to describe the use of alternative carbon sources for the microbiological synthesis of bionanocellulose and its application in the food industry.

Introduction. 2. Structure and physico-mechanical characteristics of bionanocellulose. 3. The process of synthesis of bionanocellulose and its importance for microorganisms. 4. Microorganisms used for the production of bionanocellulose. 5. Raw materials used in the synthesis of bionanocellulose. 6. Techniques of culturing microorganisms that produce bionanocellulose. 7. Possible applications of bionanocellulose in the food industry. 8. Conclusions