fraction from Geoffroea decorticans fruits flour affects key enzymes involved in metabolic syndrome, oxidative stress and inflammatory process, Food Chemistry (2015),

Minocycline (MIN) and tigecycline (TIG) are antibiotics currently used for treatment of multidrugresistant nosocomial pathogens. In this work, we show that blue light, as well as white light, modulates susceptibility to these antibiotics in a temperature-dependent manner. The modulation of susceptibility by light depends on the content of iron; an increase in iron results in a reduction in antibiotic susceptibility both under light and in the dark, though the effect is more pronounced in the latter condition. We further provide insights into the mechanism by showing that reduction in susceptibility to MIN and TIG induced by light is likely triggered by the generation of 1 O 2 , which, by a yet unknown mechanism, would ultimately lead to the activation of resistance genes such as those coding for the efflux pump AdeABC. The clinical relevance of these results may lie in surface-exposed wound infections, given the exposure to light in addition to the relatively low temperatures recorded in this type of lesion. We further show that the modulation of antibiotic susceptibility occurs not only in Acinetobacter baumannii but also in other micro-organisms of clinical relevance such as Escherichia coli and Staphylococcus aureus. Overall, our findings allow us to suggest that MIN and TIG antibiotic treatments may be improved by the inclusion of an iron chelator, in addition to keeping the wounds in the dark, a condition that would increase the effectiveness in the control of infections involving these micro-organisms.

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Light sensing has been extensively characterized in the human pathogen Acinetobacter baumannii at environmental temperatures. However, the influence of light on the physiology and pathogenicity of human bacterial pathogens at temperatures found in warm-blooded hosts is still poorly understand. In this work, we show that Staphylococcus aureus, Acinetobacter baumannii, and Pseudomonas aeruginosa (ESKAPE) priority pathogens, which have been recognized by the WHO and the CDC as critical, can also sense and respond to light at temperatures found in human hosts. Most interestingly, in these pathogens, light modulates important pathogenicity determinants as well as virulence in an epithelial infection model, which could have implications in human infections. In fact, we found that alpha-toxin-dependent hemolysis, motility, and growth under iron-deprived conditions are modulated by light in S. aureus. Light also regulates persistence, metabolism, and the ability to kill competitors in some of these microorganisms. Finally, light exerts a profound effect on the virulence of these pathogens in an epithelial infection model, although the response is not the same in the different species; virulence was enhanced by light in A. baumannii and S. aureus, while in A. nosocomialis and P. aeruginosa it was reduced. Neither the BlsA photoreceptor nor the type VI secretion system (T6SS) is involved in virulence modulation by light in A. baumannii. Overall, this fundamental knowledge highlights the potential use of light to control pathogen virulence, either directly or by manipulating the light regulatory switch toward the lowest virulence/persistence configuration. IMPORTANCE Pathogenic bacteria are microorganisms capable of producing disease. Dangerous bacterial pathogens, such as Staphylococcus aureus, Pseudomonas aeruginosa, and Acinetobacter baumannii, are responsible for serious intrahospital and community infections in humans. Therapeutics is often complicated due to resistance to multiple antibiotics, rendering them ineffective. In this work, we show that these pathogens sense natural light and respond to it by modulating aspects related to their ability to cause disease; in the presence of light, some of them become more aggressive, while others show an opposite response. Overall, we provide new understanding on the behavior of these pathogens, which could contribute to the control of infections caused by them. Since the response is distributed in diverse pathogens, this notion could prove a general concept.

Seven table potato varieties were studied for pH, soluble solids content, moisture, firmness, color, external appearance of raw tubers and flavor and texture of the fried and boiled product. Monalisa was the most appreciated variety regarding external appearance, Bartina was preferred for the flavor of the fned product while Victoria and Desiree were the best for flavor and texture of boiledpotatoes. The different scores by variety depending on frying or boiling suggest a specific use for each variety. Soluble solids content, pH, and moisture determinations showed minimal differences between varieties. Firmness was highest in the two varieties with the least moisture (Desiree and Victoria) and lowest in varieties with a high degree of moisture (Bartina and Caesar); fresh potato firmness had a positive correlation with these sensorial parameters when the product was boiled. All colorimetric purameters were useful to discriminate red skin from yellow-white skin varieties.

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The influence of sub-MIC of ciprofloxacin on the surface properties of 25 non-P mannose-resistant uropathogenic Escherichia coli (UPEC) strains was studied. Thirteen isolates responded to antibiotic treatment with an increase in haemagglutination titre and/or surface hydrophobicity, which correlated with a higher expression of surface proteins. Only UPEC strains with ciprofloxacin-enhanced hydrophobicity increased their adhesiveness to urinary catheters that correlated, in one analysed case, with a dramatic increase in the number of fimbriae peripherally located. The overall results indicate that sub-MICs of ciprofloxacin could increase the adhesiveness, and hence the risk of colonization by UPEC strains expressing mannose-resistant adhesins different from type P.

A summary of the major findings concerning light modulation in Acinetobacter baumannii, which governs aspects related to the success of this microorganism as a nosocomial pathogen, is presented. Particularly, the evidence shows that light modulates the ability of the bacteria to persist in the environment, its virulence against eukaryotic hosts and even susceptibility to certain antibiotics. The light signal is sensed through different mechanisms, in some cases involving specialized photoreceptors of the BLUF-type, whereas in others, directly by a photosensitizer molecule. We also provide new data concerning the genomic context of BLUF-domain containing proteins within the genus Acinetobacter, as well as further insights into the mechanism of light-mediated reduction in susceptibility to antibiotics. The overall information points toward light being a crucial stimulus in the lifestyle of members of the genus Acinetobacter as well as in other clinically relevant species, such as members of the ESKAPE group, playing therefore an important role in the clinical settings. INTRODUCTIONOur planet is one of the few places in universe close enough to one star that its whole surface bathes in light, and where life can take place. Each human cell and most forms of life on Earth synchronize their activities taking into account this ubiquitous environmental signal.In addition to incident solar radiation, humans and other organisms are exposed to artificial and man-made electromagnetic radiation used for indoor and outdoor lighting, medical diagnosis and treatment of diseases (1).However, the effects light produces on living organisms are far from being completely understood. In the case of bacteria, extensive knowledge has been accumulated for phototrophs, which capture light to convert it into chemical bond energy or electrochemical potential for processes dedicated to satisfy cellular energy requirements (2,3). However, information recalled during the last decades indicates that this signal also plays a role in the physiology of environmental and pathogenic chemotrophic nonphototrophic prokaryotes (3-5). Pertinent examples include physiological responses as diverse and interesting as morphogenesis in Stigmatella aurantiaca (6); carotenogenesis in Streptomyces coelicolor (7) and Myxococcus xanthus (8,9); the general response to stress in Bacillus subtilis (10,11); the attachment of Caulobacter crescentus to glass surfaces (12); the photophobic response and various biofilm functions in Escherichia coli (13,14); biofilm formation in Idiomarina loihiensis (15); motility in Acinetobacter calcoaceticus and other Acinetobacter species (16)(17)(18)(19)(20). Light signals perceived by nonphotosynthetic bacteria may even modulate their interactions with hosts (5,21). For instance, light regulates the general stress response and infection of macrophages by Brucella abortus (22,23), the virulence of Agrobacterium tumefaciens toward cucumber (24); the invasiveness of Listeria monocytogenes for enterocytes (25); the nodulation o...