Interactions of antimicrobials in milk and their detection by the disk diffusion method and Delvotest SP

The combination of more than 2 different microbials might show interactions with various effects (synergistic, additive, antagonistic, or indifferent) on target microorgnisms. An objective of this paper was to evaluate the possible interactions of several antimicrobials--those used most frequently in the treatment of mastitis in clinical veterinary practice (beta-lactam antibiotics, aminoglycosides, peptides, other antibiotics, and sulfonamides)--and their consequences on detection limits. In the model experiment with milk artificially altered by means of Delvotest SP and the disk diffusion method with Bacillus stearothermophilus var. calidolactis C 953, we observed the synergistic effect between all the antimicrobials tested. The results show that Delvotest SP is more sensitive (approximately 7.5- to 40-fold) than the disk diffusion method in estimating the detection limits of cephalosporin antibiotics.     

Flavonoid Preparations from Taraxacum officinale L. Fruits—A Phytochemical,Antioxidant and Hemostasis Studies

Dandelion (Taraxacum officinale L.) roots, leaves, and flowers have a long history of use in traditional medicine. Compared to the above organs, dandelion fruits are the least known and used. Hence, the present paper was aimed at the phytochemical analysis of T. officinale fruit extract and estimating its antiradical, antiplatelet, and antioxidant properties related to hemostasis. Methanolic extract of fruits (E1), enriched with polyphenols (188 mg gallic acid equivalents (GAE)/g), was successfully separated into cinnamic acids (E2; 448 mg GAE/g) and flavonoids (E3; 377 mg GAE/g) extracts. Flavonoid extract was further divided into four fractions characterized by individual content: A (luteolin fraction; 880 mg GAE/g), B (philonotisflavone fraction; 516 mg GAE/g), C (flavonolignans fraction; 384 mg GAE/g), and D (flavone aglycones fraction; 632 mg GAE/g). High DPPH radical scavenging activity was evaluated for fractions A and B (A > B > Trolox), medium for extracts (Trolox > E3 > E2 > E1), and low for fractions C and D. No simple correlation between polyphenol content and antiradical activity was observed, indicating a significant influence of qualitative factor, including higher anti-oxidative effect of flavonoids with B-ring catechol system compared to hydroxycinnamic acids. No cytotoxic effect on platelets was observed for any dandelion preparation tested. In experiments on plasma and platelets, using several different parameters (lipid peroxidation, protein carbonylation, oxidation of thiols, and platelet adhesion), the highest antioxidant and antiplatelet potential was demonstrated by three fruit preparations–hydroxycinnamic acids extract (E2), flavonoid extract (E3), and luteolin fraction (A). The results of this paper provide new information on dandelion metabolites, as well as their biological potential and possible use concerning cardiovascular diseases.     

Application of Green Algal Planktochlorella nurekis Biomasses to Modulate Growth of Selected Microbial Species

As microalgae are producers of proteins, lipids, polysaccharides, pigments, vitamins and unique secondary metabolites, microalgal biotechnology has gained attention in recent decades. Microalgae can be used for biomass production and to obtain biotechnologically important products. Here, we present the application of a method of producing a natural, biologically active composite obtained from unicellular microalgae of the genus Planktochlorella sp. as a modulator of the growth of microorganisms that can be used in the cosmetics and pharmaceutical industries by exploiting the phenomenon of photo-reprogramming of metabolism. The combination of red and blue light allows the collection of biomass with unique biochemical profiles, especially fatty acid composition (Patent Application P.429620). The ethanolic and water extracts of algae biomass inhibited the growth of a number of pathogenic bacteria, namely Enterococcus faecalis, Staphylococcus aureus PCM 458, Streptococcus pyogenes PCM 2318, Pseudomonas aeruginosa, Escherichia coli PCM 2209 and Candida albicans ATCC 14053. The algal biocomposite obtained according to our procedure can be used also as a prebiotic supplement. The presented technology may allow the limitation of the use of antibiotics and environmentally harmful chemicals commonly used in preparations against Enterococcus faecalis, Staphylococcus aureus, Streptococcus pyogenes, Pseudomonas aeruginosa, Escherichia coli or Candida spp.