Antimicrobial Evaluation of Novel Fatty Acid Derivatives and Other Natural Antimicrobials

The food industry has shown increased interest for novel natural antimicrobials due to consumer demand for foods with fewer synthetic additives, increased safety, quality and shelf-life. Concurrently, the emergence of drug resistant bacteria substantiates the need for newer antimicrobial agents. Alternative strategies include the use of novel antimicrobials, such as fatty acid derivatives, essential oils and bacteriocins, with proven antimicrobial properties against a diverse range of bacteria. This study investigated novel carbohydrate fatty acid (CF A) derivatives for their antibacterial activity against a range of pathogenic and spoilage bacteria. A series of mono-substituted CF A derivatives using lauric and caprylic acids were synthesized. Chemical routes allowing the attachment of the fatty acid as either an ester or ether to the monosaccharide 6-hydroxyl were developed. Structure/activity relationship studies of antimicrobial efficacy allowed some insight into the mechanism of action of these compounds. In addition, selected essential oil (EO) individual components and nisin, both alone and in combination, were also assessed for possible combination strategies with CF A derivatives. Minimum inhibitory concentration (MIC), ICso values, increase in lag phase and decrease in maximum specific growth rate were determined. Leakage of intracellular material absorbing at 260nm, Live/Dead BacLight fluorescence and ATP BacTiterGlo luminescence assays assessed membrane disrupting effects. Furthermore, a Phenotypic MicroArray assay was used to investigate bacterial cell response in the absence and presence of CF A derivatives. The laurate ether of methyl a-D-glucopyranoside (9a) and laurate ester of methyl a-D-mannopyranoside (4c) showed the highest growth-inhibitory effect. CFA derivatives were significantly more effective against Gram positive than Gram negative bacteria. The analysis of both ester and ether fatty acid derivatives of the same carbohydrate, in tandem with alpha and beta configuration of the carbohydrate moiety suggest that the carbohydrate moiety is involved in the antimicrobial activity of the fatty acid derivatives and that the nature of the bond also has a significant effect on efficacy. Membrane damage was observed and may account for at least a component of the mode of action of these compounds. The ATP assay and phenotypic responses suggested that another mechanism of action might also account for the antimicrobial activity of the beta lauric ether derivative (compound 9b). Carvacrol and thymol were found to have the highest antimicrobial activity, followed by citral. Nisin in combination with carvacrol, thymol and citral showed additive effects against Listeria spp. The antimicrobial effect of the combination was improved by lowering the pH from neutral to pH6. CF A derivatives with different structures have great potential for developing antibacterial agents relevant to the food and health care industries. Nisin in combination with individual EO components could lead to useful efficacy as an alternative natural preservative

Diet among Siberian Yup'iks of Alaska and the implications for cardiovascular disease

Thesis (Ph.D.) University of Alaska Fairbanks, 1996I investigated dietary factors associated with cardiovascular disease and their relation to blood lipids among Siberian Yup'iks. This study was prompted by reports of increasing mortality from cardiovascular disease in Alaska Natives and the need to know to what extent their unique diet may influence cardiovascular disease. Information on dietary intakes was collected in 1992 using two recall methods, from over one-half of the Siberian Yup'ik Eskimos (n = 65) $\geq$40 years-of-age in Gambell, Alaska, as part of a comprehensive screening for diabetes and cardiovascular disease. Based on analysis of 29 nutrients, mean daily intakes of monounsaturated fats and antioxidants--vitamin E, selenium, and vitamin C (among men)--exceeded US recommendations. Mean intake of n-3 fatty acids (7.0 g/d) exceeded the level associated with favorable physiologic responses (>3 g/d) and was comparable to that of Greenlandic Eskimos (8.6 g/d). Although fat intake was high (44% of total energy for men, 42% for women), saturated (11%) and polyunsaturated fats (8%) were not different $(P>$ 0.05), but energy from monounsaturated fat was greater (18% vs. 13%, $P50$\alpha$-tocopherol and n-6 fatty acids (r = 0.888). When multiple regression was applied among all participants,$\alpha$-tocopherol and fresh bird were associated with reduced LDL-HDL ratio; body-mass index, pizza and syrup were positively associated. Adding obesity to this equation increased the percent of variation explained (42% to 59%). Dietary advice includes maintaining desirable weight, consuming a diet moderate in fat, rich in monounsaturated fats and low in saturated fats, and foods rich in n-3 fatty acids--e.g. Native foods--and vitamin E

Lauric acid is an inhibitor of Clostridium difficile growth in vitro and reduces inflammation in a mouse infection model

Indexación: Scopus.Clostridium difficile is a Gram-positive, spore-forming anaerobic human gastrointestinal pathogen. C. difficile infection (CDI) is a major health concern worldwide, with symptoms ranging from diarrhea to pseudomembranous colitis, toxic megacolon, sepsis, and death. CDI onset and progression are mostly caused by intestinal dysbiosis and exposure to C. difficile spores. Current treatment strategies include antibiotics; however, antibiotic use is often associated with high recurrence rates and an increased risk of antibiotic resistance. Medium-chain fatty acids (MCFAs) have been revealed to inhibit the growth of multiple human bacterial pathogens. Components of coconut oil, which include lauric acid, have been revealed to inhibit C. difficile growth in vitro. In this study, we demonstrated that lauric acid exhibits potent antimicrobial activities against multiple toxigenic C. difficile isolates in vitro. The inhibitory effect of lauric acid is partly due to reactive oxygen species (ROS) generation and cell membrane damage. The administration of lauric acid considerably reduced biofilm formation and preformed biofilms in a dose-dependent manner. Importantly, in a mouse infection model, lauric acid pretreatment reduced CDI symptoms and proinflammatory cytokine production. Our combined results suggest that the naturally occurring MCFA lauric acid is a novel C. difficile inhibitor and is useful in the development of an alternative or adjunctive treatment for CDI.https://www.frontiersin.org/articles/10.3389/fmicb.2017.02635/ful

Isolierte Gehirn-Kapillaren als in vitro-Modell der Blut-Hirn Schranke

Ziel war, ein in vitro-Modell der Blut-Hirn Schranke zu erarbeiten, anhand dessen man insbesondere den Einfluß der ABC-Transporter-Proteine P-Glykoprotein und Mrp2 auf den Transport von Arzneistoffen an der Blut-Hirn Schranke untersuchen kann. Es wurde untersucht, ob frisch isolierte Kapillaren aus dem Gehirn von Schweinen für diese Fragestellung geeignet sind, da bisher bekannte und verwendete Modelle wie beispielsweise isolierte und kultivierte Gehirn-Endothelzellen diesbezüglich Nachteile besitzen. Es wurden morphologisch und funktionell intakte Gehirn-Kapillaren mechanisch aus dem Gehirn von Schweinen isoliert. Diese Kapillaren waren vital und zeigten typische Eigenschaften der Blut-Hirn Schranke wie beispielsweise dichte tight junctions, Exprimierung des Markerproteins 'von Willebrand-Faktor', sowie erhöhte Aktivitäten der Markerenzyme g-Glutamyl-Transpeptidase und Alkalische Phosphatase. Durch immunhistochemische Färbungen, Western Blots sowie Sekretions-Untersuchungen am konfokalen Lasermikroskop mit spezifischen Substraten und Hemmstoffen konnte belegt werden, daß sowohl P-Glykoprotein als auch Mrp2 in den Endothelzellen der frisch isolierten Kapillaren exprimiert werden und auch funktionell aktiv sind. Abschließend wurde beispielhaft anhand des in der vorliegenden Arbeit untersuchten und charakterisierten in vitro-Modells der Blut-Hirn Schranke in Form frisch isolierter Gehirn-Kapillaren der Transport der beiden Arzneistoffe Ivermectin und Octreotid an der Blut-Hirn Schranke auf eine mögliche Beteiligung der Transporter-Proteine P-Glykoprotein und Mrp2 hin untersucht. Für das Anthelminthikum Ivermectin konnte aufgrund von Sekretions-Untersuchungen gezeigt werden, daß P-Glykoprotein einen limitierenden Faktor bezüglich der Gehirngängigkeit an der Blut-Hirn Schranke darstellt. Für das Somatostatin-Analogon Octreotid ergab sich, daß sowohl P-Glykoprotein als auch Mrp2 an dessen Transport an der Blut-Hirn Schranke beteiligt sind

Vina: proyecto de vivienda en altura que busca la integración de la naturaleza tras el extractivismo urbano en Barranquilla

En la ciudad el extractivismo urbano es algo que ha generado cambios en distintos aspectos, y es que este implica la intensa explotación de los recursos urbanos de la localidad, como el territorio, la tierra y los bienes culturales, con fines económicos a corto plazo. Este hecho ha generado desafíos sobre la planificación urbana, los efectos ambientales, el legado cultural y la desigualdad social. En consecuencia, se está tratando de fomentar un desarrollo urbano más justo y sostenible en la ciudad. El resultante a este estudio es VINA, el cual es un proyecto vivienda en altura que busca la integración de la naturaleza en entornos urbanos, la influencia del extractivismo urbano logra que se implemente la incorporación de elementos naturales en el diseño y desarrollo del proyecto arquitectónico. Esto incluye el anexo de áreas verdes, huertas y espacios abiertos. Esta relación puede contribuir a mejorar la calidad ambiental de los espacios urbanos.PregradoArquitect

In Vitro Antimicrobial Activity and Mechanism of Action of Novel Carbohydrate Fatty Acid Derivatives Against Staphylococcus Aureus and MRSA

Aims: This study investigates the antimicrobial activity and mode of action of novel carbohydrate fatty acid (CFA) derivatives against Staphylococcus aureus and methicillin-resistant Staph. aureus (MRSA). Methods and Results: Minimum inhibitory concentrations (MIC) and the effect of CFA derivatives on lag phase were determined using a broth microdilution method. Lauric acid carbohydrate esters and corresponding ether analogs showed the greatest antimicrobial activity with MIC values between 0.04 to 0.16mmol l-1. Leakage studies at 260nm following exposure to CFA derivatives at 4X MIC showed a significant increase in membrane permeability for all compounds, after ca. 15 minutes exposure except for the lauric beta ether CFA derivative. Further assessment using both BacLight and luminescence ATP assays, confirmed that an increase in membrane permeability and reduced metabolic activity was associated with CFA treatment. Conclusions: All strains were significantly inhibited by the novel compounds studied and efficacy was related to specific structural features. Cell-membrane permeabilization was associated with CFA treatment and may account for at least a component of the mode of action of these compounds. Significance and Impact of Study: This study reports the antimicrobial action of CFA compounds against a range of Staph. aureus and MRSA strains, and provides insights into their mode of action

The Antimicrobial Efficacy and Structure Activity Relationship of Novel Carbohydrate Fatty Acid Derivatives Against Listera spp. and Food Spoilage Microorganisms

Novel mono-substituted carbohydrate fatty acid (CFA) esters and ethers were investigated for their antibacterial activity against a range of pathogenic and spoilage bacteria focussing on Listeria monocytogenes. Carbohydrate derivatives with structural differences enable comparative studies on the structure/activity relationship for antimicrobial efficacy and mechanism of action. The antimicrobial efficacy of the synthesized compounds was compared with commercially available compounds such as monolaurin and monocaprylin, as well as the pure free fatty acids, lauric acid and caprylic acid, which have proven antimicrobial activity. Compound efficacy was compared using an absorbance based broth microdilution assay to determine the minimum inhibitory concentration (MIC), increase in lag phase and decrease in maximum growth rate. Among the carbohydrate derivatives synthesized, lauric ether of methyl α-d-glucopyranoside and lauric ester of methyl α-d-mannopyranoside showed the highest growth-inhibitory effect with MIC values of 0.04 mM, comparable to monolaurin. CFA derivatives were generally more active against Gram positive bacteria than Gram negative bacteria. The analysis of both ester and ether fatty acid derivatives of the same carbohydrate, in tandem with alpha and beta configuration of the carbohydrate moiety suggest that the carbohydrate moiety is involved in the antimicrobial activity of the fatty acid derivatives and that the nature of the bond also has a significant effect on efficacy, which requires further investigation. This class of CFA derivatives has great potential for developing antibacterial agents relevant to the food industry, particularly for control of Listeria or other Gram-positive pathogens

Conjugated docosahexaenoic acid suppresses KPL-1 human breast cancer cell growth in vitro and in vivo: potential mechanisms of action

Introduction The present study was conducted to examine the effect of conjugated docosahexaenoic acid (CDHA) on cell growth, cell cycle progression, mode of cell death, and expression of cell cycle regulatory and/or apoptosis-related proteins in KPL-1 human breast cancer cell line. This effect of CDHA was compared with that of docosahexaenoic acid (DHA). Methods KPL-1 cell growth was assessed by colorimetric 3- (4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay; cell cycle progression and mode of cell death were examined by flow cytometry; and levels of expression of p53, p21Cip1/Waf1, cyclin D1, Bax, and Bcl-2 proteins were examined by Western blotting analysis. In vivo tumor growth was examined by injecting KPL-1 cells subcutaneously into the area of the right thoracic mammary fat pad of female athymic mice fed a CDHA diet. Results CDHA inhibited KPL-1 cells more effectively than did DHA (50% inhibitory concentration for 72 hours: 97 μmol/l and 270 μmol/l, respectively). With both CDHA and DHA growth inhibition was due to apoptosis, as indicated by the appearance of a sub-G1 fraction. The apoptosis cascade involved downregulation of Bcl-2 protein; Bax expression was unchanged. Cell cycle progression was due to G0/G1 arrest, which involved increased expression of p53 and p21Cip1/Waf1, and decreased expression of cyclin D1. CDHA modulated cell cycle regulatory proteins and apoptosis-related proteins in a manner similar to that of parent DHA. In the athymic mouse system 1.0% dietary CDHA, but not 0.2%, significantly suppressed growth of KPL-1 tumor cells; CDHA tended to decrease regional lymph node metastasis in a dose dependent manner. Conclusion CDHA inhibited growth of KPL-1 human breast cancer cells in vitro more effectively than did DHA. The mechanisms of action involved modulation of apoptosis cascade and cell cycle progression. Dietary CDHA at 1.0% suppressed KPL-1 cell growth in the athymic mouse system.</p

Research with Arctic peoples: Unique research opportunities in heart, lung, blood and sleep disorders. Working group summary and recommendations

Arctic peoples are spread over eight countries and comprise 3.74 million residents, of whom 9% are indigenous. The Arctic countries include Canada, Finland, Greenland (Denmark), Iceland, Norway, Russia, Sweden and the United States. Although Arctic peoples are very diverse, there are a variety of environmental and health issues that are unique to the Arctic regions, and research exploring these issues offers significant opportunities, as well as challenges. On July 28-29, 2004, the National Heart, Lung, and Blood Institute and the Canadian Institutes of Health Research co-sponsored a working group entitled Research with Arctic Peoples: Unique Research Opportunities in Heart, Lung, Blood and Sleep Disorders . The meeting was international in scope with investigators from Greenland, Iceland and Russia, as well as Canada and the United States. Multiple health agencies from Canada and the United States sent representatives. Also attending were representatives from the International Union for Circumpolar Health (IUCH) and the National Indian Health Board. The working group developed a set of ten recommendations related to research opportunities in heart, lung, blood and sleep disorders; obstacles and solutions to research implementation; and ways to facilitate international comparisons. These recommendations are expected to serve as an agenda for future research