A first insight into the Polish Bochnia Salt Mine metagenome.

The Bochnia Salt Mine is one of the oldest mines in Europe. It was established in the thirteenth century, and actively operated until 1990. The mine has been placed on the UNESCO World Heritage List. Previous research describing Polish salt mines has been focused on bioaerosol characteristics and the identification of microorganisms potentially important for human health. The use of Polish salt mines as inhalation chambers for patients of health resorts has also been investigated. Nevertheless, the biodiversity of salt mines associated with biotechnological potential has not been well characterized. The present study paper examines the biodiversity of microorganisms in the Bochnia Salt Mine based on 16S rRNA gene and shotgun sequencing. Biodiversity studies revealed a significantly higher relative abundance of Chlamydiae at the first level of the mine (3.5%) compared to the other levels (< 0.1%). Patescibacteria microorganisms constituted a high percentage (21.6%) in the sample from site RA6. Shotgun sequencing identified 16 unique metagenome-assembled genomes (MAGs). Although one was identified as Halobacterium bonnevillei, the others have not yet been assigned to any species; it is possible that these species may be undescribed. Preliminary analyses of the biotechnological and pharmaceutical potential of microorganisms inhabiting the mine were also performed, and the biosynthetic gene cluster (BGC) profiles and antimicrobial peptide (AMP) coding genes in individual samples were characterized. Hundreds of BGCs and dozens of AMP coding genes were identified in metagenomes. Our findings indicate that Polish salt mines are promising sites for further research aimed at identifying microorganisms that are producers of potentially important substances with biotechnological and pharmaceutical applications.

Effect of oxidation and in vitro intestinal hydrolysis on phospholipid toxicity towards HT29 cell line serving as a model of human intestinal epithelium.

Oxidation of food-derived phospholipids (PLs) can influence nutrient digestion and induce oxidative stress in gastrointestinal epithelium. In this study, hen egg yolk PL fraction was used to evaluate the effect of lipoxygenase (LOX)-induced PL oxidation on the rate of PL hydrolysis catalyzed by pancreatic phospholipase A2 (PLA2) in the presence of bile salts (BSs). Then, PL/BS solutions containing native or oxidized PLs were used in in vitro intestinal digestion to assess the effect of PL oxidation and hydrolysis on the toxicity towards HT29 cell line. Based on the obtained results, we suggest that hexanal and (E)-2-nonenal, formed by the decomposition of PL hydroperoxides, inhibited PLA2 activity. The cell exposure to simulated intestinal fluid (SIF) containing BSs decreased HT29 cell viability and significantly damaged cellular DNA. However, the genotoxic effect was reversed in the presence of all tested PL samples, while the protective effect against the BS-induced cytotoxicity was observed for native non-hydrolyzed PLs, but was not clearly visible for other samples. This can result from an overlap of other toxic effects such as lipotoxicity or disturbance of cellular redox homeostasis. Taking into account the data obtained, it was proposed that the PLA2 activity decline in the presence of PL oxidation products may be a kind of protective mechanism against rapid release of oxidized FAs characterized by high cytotoxic effect towards intestinal epithelium cells.

Interactions between polyphenolic antioxidants quercetin and naringenin dictate the distinctive redox-related chemical and biological behaviour of their mixtures.

Food synergy concept is suggested to explain observations that isolated antioxidants are less bioactive than real foods containing them. However, mechanisms behind this discrepancy were hardly studied. Here, we demonstrate the profound impact of interactions between two common food flavonoids (individual: aglycones quercetin-Q and naringenin-N- or their glycosides rutin-R and naringin-N+ vs. mixed: QN- and RN+) on their electrochemical properties and redox-related bioactivities. N- and N+ seemed weak antioxidants individually, yet in both chemical and cellular tests (DPPH and CAA, respectively), they increased reducing activity of mixtures synergistically. In-depth measurements (differential pulse voltammetry) pointed to kinetics of oxidation reaction as decisive factor for antioxidant power. In cellular (HT29 cells) tests, the mixtures exhibited properties of a new substance rather than those of components. Pure flavonoids did not influence proliferation; mixtures stimulated cell growth. Individual flavonoids tended to decrease global DNA methylation with growing concentration; this effect was more pronounced for mixtures, but not concentration-dependent. In nutrigenomic studies, expression of gene set affected by QN- differed entirely from common genes modulated by individual components. These results question the current approach of predicting bioactivity of mixtures based on research with isolated antioxidants.

Upper-airway dysbiosis related to frequent sweets consumption increases the risk of asthma in children with chronic rhinosinusitis.

BACKGROUND: Innate immunity response to local dysbiosis seems to be one of the most important immunologic backgrounds of chronic rhinosinusitis (CRS) and concomitant asthma. We aimed to assess clinical determinants of upper-airway dysbiosis and its effect on nasal inflammatory profile and asthma risk in young children with CRS. METHODS: We recruited one hundred and thirty-three children, aged 4-8 years with doctor-diagnosed CRS with or without asthma. The following procedures were performed in all participants: face-to-face standardized Sinus and Nasal Quality of Life questionnaire, skin prick test, taste perception testing, nasopharynx swab, and sampling of the nasal mucosa. Upper-airway dysbiosis was defined separately by asthma-specific microbiome composition and reduced biodiversity. Multivariate methods were used to define the risk factors for asthma and upper-airway dysbiosis and their specific inflammatory profile of nasal mucosa. RESULTS: The asthma-specific upper-airway microbiome composition reflected by the decreased ratio of Patescibacteria/Actinobacteria independently of atopy increased the risk of asthma (OR:8.32; 95%CI: 2.93-23.6). This asthma-specific microbiome composition was associated with ≥ 7/week sweet consumption (OR:2.64; 95%C:1.11-6.28), reduced biodiversity (OR:3.83; 95%CI:1.65-8.87), the presence of Staphylococcus strains in the nasopharynx (OR:4.25; 95%CI:1.12-16.1), and lower expression of beta-defensin 2, IL-5, and IL-13 in the nasal mucosa. The reduced biodiversity was associated with frequent antibiotic use and with a higher nasal expression of IL-17 and T1R3 (sweet taste receptor). In asthmatic children, reduced sweet taste perception was observed. CONCLUSIONS: Specific upper-airway dysbiosis related to frequent sweet consumption, frequent antibiotic courses, and altered nasal immune function increases the risk of asthma in young children with CRS.

Interactions between bioactive components determine antioxidant, cytotoxic and nutrigenomic activity of cocoa powder extract.

Numerous studies have shown, rather disappointingly, that isolated bioactive phytochemicals are not as biologically effective as natural plant products. Such a discrepancy may be explained by the concept of food synergy, which was verified in this research for cocoa extract versus its major components with regard to cancer chemoprevention. The evaluation embraced the relationship between redox properties evaluated in cell-free systems with the aid of free radicals scavenging method and differential pulse voltammetry, and redox associated anticarcinogenic activities (cellular antioxidant activity, cytotoxicity, nutrigenomic activity) in human colon adenocarcinoma cell line exposed to either cocoa powder extract or artificial mixtures of cocoa bioactives at matching concentrations. In contrast to expectations, our results showed that the stepwise enrichment with antioxidants caused no gradual increase in the antioxidant activity of the model mixtures; also, these model mixtures did not reach the reducing potential of cocoa in the cell-free systems or cellular model employed. Further, the biological activities examined in colon adenocarcinoma cells did not alter in a stepwise manner that could reflect the gradual changes in composition of bioactive ingredients. In conclusion, the experiments presented here showed that the growing complexity of a mixture of phytochemicals seems to create a new redox bioactive substance rather than enrich the mixture with new activities, characteristic of the compound added. It follows that no simple, predictable relationship can be expected between the chemopreventive potential and the composition of real food items containing a complicated set of non-toxic redox active ingredients. Our observations suggest that the interactions between different bioactive compounds and food matrix components are cooperating factors determining the final bioactivity of foods.

Prophylaxis of Non-communicable Diseases: Why Fruits and Vegetables may be Better Chemopreventive Agents than Dietary Supplements Based on Isolated Phytochemicals?

The World Health Organization (WHO) report from 2014 documented that non-communicable socalled civilization diseases such as cardiovascular disease, chronic respiratory diseases, cancer or type 2 diabetes are responsible for over 50% of all premature deaths in the world. Research carried out over the past 20 years has provided data suggesting that diet is an essential factor influencing the risk of development of these diseases. The increasing knowledge on chemopreventive properties of certain food ingredients, in particular, those of plant origin, opened the discussion on the possibility to use edible plants or their active components in the prevention of these chronic diseases. Health-promoting properties of plant foods are associated with the presence of secondary metabolites that can affect many biological mechanisms of critical importance to the proper functioning of the human organism. Particularly, there have been numerous investigations indicating strong physiological effects of bioactive plant phenols belonging to the flavonoid family. These observations initiated mass production of dietary supplements containing flavonoids commercialized under the name antioxidants, even if their chemical properties did not justify such a term. However, epidemiological studies revealed that isolated bioactive phytochemicals are not as effective as fruits and vegetables containing these substances whereas they are of interest of the functional food industry. In this paper, the critical assessment of reasons for this turn of events has been attempted and the concept of food synergy has been suggested as a future strategy of dietary chemoprevention.

The relationship between standard reduction potentials of catechins and biological activities involved in redox control.

Redox homeostasis involves factors that ensure proper function of cells. The excess reactive oxygen species (ROS) leads to oxidative stress and increased risk of oxidative damage to cellular components. In contrast, upon reductive stress, insufficient ROS abundance may result in faulty cell signalling. It may be expected that dietary antioxidants, depending on their standard reduction potentials (E°), will affect both scenarios. In our study, for the first time, we systematically tested the relationship among E°, chemical properties, and biological effects in HT29 cells for a series of structurally different catechins and a major endogenous antioxidant - glutathione (GSH), at both physiological and dietary concentrations. Among chemical antioxidant activity tests, the strongest correlation with E° was seen using a DPPH assay. The values of E° were also highly correlated with cellular antioxidant activity (CAA) values determined in HT29 cells. Our results indicated that physiological concentrations (1-10 µM) of tested catechins stabilized the redox status of cells, which was not exhibited at higher concentrations. This stabilization of redox homeostasis was mirrored by constant, dose and E° independent CAA values, uninhibited growth of HT29 cells, modulation of hydrogen peroxide-induced DNA damage, as well as effects at the genomic level, where either up-regulation of three redox-related genes (ALB, CCL5, and HSPA1A) out of 84 in the array (1 µM) or no effect (10 µM) was observed for catechins. Higher catechin concentrations (over 10 µM) increased CAA values in a dose- and E°-dependent manner, caused cell growth inhibition, but surprisingly did not protect HT29 cells against reactive oxygen species (ROS)-induced DNA fragmentation. In conclusion, dose-dependent effects of dietary antioxidants and biological functions potentially modulated by them may become deregulated upon exposure to excessive doses.

Determination of antioxidantactivity of phytochemicals in cellular models by fluorescence/luminescence methods.

As soon as the role of Reactive Oxygen Species (ROS) in so-called civilization diseases, which include non-infectious chronic diseases such as cancer, diabetes or high blood pressure has been discovered, and the possibility of employing antioxidants as a remedy for these diseases have been proposed, scientists developed a broad spectrum of methods to determine antioxidant activity of pure chemicals and plant extracts, as well as dietary supplements. Most of these methods are based on simple redox reactions between antioxidant and ROS (for example ABTS, DPPH, or FRAP tests). However, chemical methods of assessing antioxidant activity are rarely biologically relevant. They do not mirror the real effect of antioxidants in living organisms, because they are used in non-physiological conditions of temperature and pH; neither they take metabolism nor intracellular transport under consideration. The perfect model for assessment of antioxidant activity in living organisms would be human or animal model, but such determinations are very complicated and often ambiguous. The current best alternative to chemical and human tests are assays employing cell culture models being less expensive than human tests, yet still reflecting biological systems more convincingly than chemical assays. Cellular antioxidant assays are performed under physiological pH and temperature, but most importantly, they take metabolism and intracellular transport under consideration. In this review, we present cellular tests used to determine antioxidant activity that are based on luminescence and fluorescence methods.

Antioxidant and antimicrobial properties of bioactive phytochemicals from cranberry.

In the rational human diet, the important role of fruits and vegetables, which are a source of bioactive phytochemicals, is emphasized. Among fruits particular attention, due to a number of documented health-promoting properties, is focused on cranberry. This fruit is characterized by the high content of antioxidant phenolic compounds, which may support the natural antioxidant defense system of the body in the prevention of damage caused by oxidative stress induced by reactive oxygen species (ROS). Therefore, cranberry is suggested for the prevention of civilization diseases such as atherosclerosis, hypertension and cancer, whose etiology is associated directly with oxidative stress. The health-promoting potential of cranberry is also associated with its antibacterial activity resulting from the presence of proanthocyanidins (PAC) type A with documented anti-adherence properties. The best-established medical applications of cranberry fruits are prevention and treatment of bacterial infections of the urinary tract (UTI), infections of gastric mucosa, and infections of the oral cavity. Due to the widespread use of cranberry and pharmaceutical preparations containing PACs in treating UTI, it is very important to evaluate the absorption, bioavailability and metabolism of these compounds in the human body.