Chemical composition and antioxidant activity of some fermented vegetable juices compared to fresh vegetable juices

The aims of this study were to evaluate (1) the conversion rate of nitrate to nitrite in red pepper and tomato juices, and (2) the total polyphenols content (TPC), total carotenoid content (TCC) and antioxidant activity (AA) of fresh compared to fermented juices obtained from red pepper (Capsicum annuum L.) and tomato (Solanum lycopersicum L.). Red pepper and tomato juices were obtained from frozen fruits and fermentation was made in the presence of Staphylococcus xylosus ATCC strain 29971 (108 CFU/mL). The nitrate and nitrite concentration (ppm) was determined from 6 to 6 hours for 30 hours. For nitrate and nitrite determination, colorimetric methods were used. After 30 hours of incubation at 37°C, it was found a conversion rate of nitrate to nitrite of 85.10 % for red pepper, and 81.87 % for tomato. Fermented juices of red pepper and tomato showed similar conversion yield of nitrate to nitrite. The TPC, TCC and AA were determined for fresh and fermented juices using colorimetric methods. TPC, expressed as mg gallic acid equivalents/100 mL (mg GAE/100 mL) and TCC, expressed as mg β carotene equivalents/100 g wet weight (mg β-CarE/100g WW), varied considerably between unfermented and fermented sterilized juices, with highest concentrations in the unfermented pepper and tomato juices (42.34 ± 2.82 and 57.92 ± 3.86, respectively) for polyphenols, and (31.85 ± 2.12 and 61.76 ± 4.12, respectively) for carotenoids. AA was expressed as % Inhibition of DPPH•. After fermentation, the antioxidant activity decreased for both juices, the decrease rate was 39.50% for red pepper and 32.18% tomato juice

Detection and Molecular Characterization of Canine Babesiosis Causative Agent <i>Babesia canis</i> in Naturally Infected Dogs in the Dobrogea Area (Southeastern Romania)

Canine babesiosis is an emerging tick-borne disease of major veterinary concern in Europe. Its prevalence has increased in the last two decades and is spreading rapidly toward the north. The aim of this study was to investigate the genetic diversity of Babesia spp. strains isolated from naturally infected dogs in a tick-endemic area (Dobrogea) in southeastern Romania. For this purpose, a total of twenty-three samples from dogs diagnosed with various clinical forms of babesiosis, evaluated by means of clinical history, physical examination, and hematological tests, were subjected to a molecular investigation using PCR, sequencing analysis, and genetic characterization. A microscopic examination of thin Diff-quick-stained blood smears revealed large intra-erythrocytic Babesia piroplasms in all dogs. The PCR and sequencing analysis results indicated the presence of Babesia canis in 22 dogs (95.7%) and Babesia vogeli in 1 dog (4.3%). Among the B. canis isolates, two genotypes were distinguished based on two nucleotide substitutions (GA→AG) observed in the 18S rRNA gene sequences (at positions 609 and 610), with the AG genotype predominating (54.5% of samples), while the GA variant was identified in 9.1% of samples. In the remaining isolates (36.4%), both variants were identified. The B. vogeli-positive dog also tested positive for antibodies against Ehrlichia canis and displayed severe disease. This study reports, for the first time, the presence of genetically heterogenic B. canis strains in dogs with clinical babesiosis in Romania. These findings provide a basis for future studies on the relationship between the genetic structure of the causative agents of canine babesiosis in Romania and the course of the disease

Structural Analysis of Sortase A Inhibitors

Bacterial sortases are cysteine transpeptidases that regulate the covalent linkage of several surface protein virulence factors in Gram-positive bacteria. Virulence factors play significant roles in adhesion, invasion of host tissues, biofilm formation and immune evasion, mediating the bacterial pathogenesis and infectivity. Therefore, sortases are emerging as important targets for the design of new anti-infective agents. We employed a computational study, based on structure derived descriptors and molecular fingerprints, in order to develop simple classification methods which could allow predicting low active or high active SrtA inhibitors. Our results indicate that a highly active SrtA inhibitor has a molecular weight ranging between 180 and 600, contains one up to four nitrogen atoms, up to three oxygen atoms and under 18 hydrogen atoms. Also the hydrogen acceptor number and the molecular flexibility, as assessed by the number of rotatable bounds, have emerged as the most relevant descriptors for SrtA affinity. The Bemis-Murcko scaffolding revealed favoured scaffolds as containing at least two ring structures bonded directly or merged in a condensed cycle. This data represent a valuable tool for identifying new potent SrtA inhibitors, potential anti-virulence agents targeted against Gram-positive bacteria, including multiresistant strains

Molecular Docking and Screening Studies of New Natural Sortase A Inhibitors

To date, multi-drug resistant bacteria represent an increasing health threat, with a high impact on mortality, morbidity, and health costs on a global scale. The ability of bacteria to rapidly and permanently acquire new virulence factors and drug-resistance elements requires the development of new antimicrobial agents and selection of new proper targets, such as sortase A. This specific bacterial target plays an important role in the virulence of many Gram-positive pathogens, and its inhibition should produce a mild evolutionary pressure which will not favor the development of resistance. A primary screening using a fluorescence resonance energy transfer assay was used to experimentally evaluate the inhibitory activity of several compounds on sortase A. Using molecular docking and structure-activity relationship analyses, several lead inhibitors were identified, which were further tested for antimicrobial activity using the well diffusion test and minimum inhibitory concentration. The toxicity was assessed using the Daphnia magna test and used as a future screening filter. Three natural compounds were identified in this study as promising candidates for further development into therapeutically useful anti-infective agents that could be used to treat infections caused by multi-drug resistant bacterial pathogens which include sortase A in their enzymatic set

A bioanalytical approach of chemical composition, bioactivity and cytotoxicity of <i>Berteroa incana</i> L. herb

<p><i>Berteroa incana</i> is a wild herb widespread in temperate zones which was practically not studied for its biological effects. Methanolic and aqueous extracts of <i>B. incana</i> were assessed for the content in polyphenols and the related antioxidant and antimicrobial activities and the polysaccharide extract for the content in saccharides and the associated cytostatic effect. The results obtained highlighted that the methanolic extracts of <i>B. incana</i> contain moderate amounts of polyphenols, the most representative been isoquercitrin 4.41 ± 0.02 mg100 g⁻¹dry weight plant material (DW), quercetin 4.21 ± 0.05, sinapic acid 5.23 ± 0.12 and ferulic acid 5.05 ± 0.12 mg 100 g⁻¹DW, with correlated moderate antioxidant activities (IC₅₀ 13.40 ± 0.01 μg mL⁻¹) and absent antibacterial activity. The polysaccharide fraction showed high content in saccharides, especially in arabinose (312.22 ± 7.54 mg g⁻¹ polysaccharide extract) and glucose (279.22 ± 5.59), and promising cytostatic effect.</p