446 research outputs found

    Kupanje u Dravi ā€“ Ā»idemo nizvodnoĀ«

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    This paper takes a look into the past, being by way of a first step, as it were Ā»dipping a toe in the cold waterĀ«, creating a few waves and then taking us up to the present day, with some ideas for the future of Ā»bathing in the DravaĀ«. We associate various things with the word Ā»bathingĀ«: washing and hygiene, recreation and leisure, sport and fitness. All these things were once possible in the river Drava (Drau) and certainly could be again, at least in certain selected locations. In Carinthia too, the Ā»land of 1,000 lakesĀ« ā€“ and not just in Carinthia ā€“ bathing in the river would be a meaningful and attractive addition to existing tourism facilities, and need not be regarded as being in competition with them.Ovaj nas rad vodi u proÅ”lost, kao da se radi o prvom koraku, kao kada bismo Ā»uronili stopala u hladnu voduĀ«, napravili nekoliko valova i zatim se vratili u sadaÅ”njost s nekoliko ideja vezanih uz budućnost Ā»kupanja u DraviĀ«. Uz riječ Ā»kupanjeĀ« se obično povezuju različite stvari: pranje i higijena, rekreacija, opuÅ”tanje i fitnes. Sve te stvari su se nekada odvijale na rijeci Dravi i sigurno bi se opet mogle odvijati, barem na pojedinim odabranim lokacijama. U KoruÅ”koj, Ā»saveznoj državi s 1,000 jezeraĀ« ā€“ i ne samo u KoruÅ”koj ā€“ kupanje u rijeci bila bi smislena i atraktivna nadopuna postojeće turističke ponude, te se takav oblik aktivnosti ne treba smatrati konkurencijom postojećoj turističkoj ponudi

    Messages from the other side: parasites receive damage cues from their host plants

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    As sessile organisms, plants rely on their environment for cues indicating imminent herbivory. These cues can originate from tissues on the same plant or from different individuals. Since parasitic plants form vascular connections with their host, parasites have the potential to receive cues from hosts that allow them to adjust defenses against future herbivory. However, the role of plant communication between hosts and parasites for herbivore defense remains poorly investigated. Here we examined the effects of damage to lupine hosts (Lupinus texensis) on responses of the attached hemiparasite (Castilleja indivisa), and indirectly, on a specialist herbivore of the parasite, buckeyes (Junonia coenia). Lupines produce alkaloids as defenses against herbivore that can be taken up by the parasite. We found that damage to lupine host plants by beet armyworm (Spodoptera exigua) significantly increased jasmonic acid (JA) levels in both the lupine host and parasite, suggesting uptake of phytohormones or priming of parasite defenses using host cues. However, lupine host damage did not induce changes in alkaloid levels in the hosts or parasites. Interestingly, the parasite had substantially higher concentrations of JA and alkaloids compared to lupine host plants. Buckeye herbivores consumed more parasite tissue when attached to damaged compared to undamaged hosts. We hypothesize that increased JA due to lupine host damage induced higher iridoid glycosides in the parasite, which are feeding stimulants for this specialist herbivore. Our results demonstrate that damage to hosts may affect both parasites and associated herbivores, indicating cascading effects of host damage on multiple trophic levels

    Antimicrobial and Efflux Pump Inhibitory Activity of Caffeoylquinic Acids from Artemisia absinthium against Gram-Positive Pathogenic Bacteria

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    Background: Traditional antibiotics are increasingly suffering from the emergence of multidrug resistance amongst pathogenic bacteria leading to a range of novel approaches to control microbial infections being investigated as potential alternative treatments. One plausible antimicrobial alternative could be the combination of conventional antimicrobial agents/antibiotics with small molecules which block multidrug efflux systems known as efflux pump inhibitors. Bioassay-driven purification and structural determination of compounds from plant sources have yielded a number of pump inhibitors which acted against gram positive bacteria. Methodology/Principal Findings: In this study we report the identification and characterization of 4ā€²,5ā€²-O-dicaffeoylquinic acid (4ā€²,5ā€²-ODCQA) from Artemisia absinthium as a pump inhibitor with a potential of targeting efflux systems in a wide panel of Gram-positive human pathogenic bacteria. Separation and identification of phenolic compounds (chlorogenic acid, 3ā€²,5ā€²-ODCQA, 4ā€²,5ā€²-ODCQA) was based on hyphenated chromatographic techniques such as liquid chromatography with post column solid-phase extraction coupled with nuclear magnetic resonance spectroscopy and mass spectroscopy. Microbial susceptibility testing and potentiation of well know pump substrates revealed at least two active compounds; chlorogenic acid with weak antimicrobial activity and 4ā€²,5ā€²-ODCQA with pump inhibitory activity whereas 3ā€²,5ā€²-ODCQA was ineffective. These intitial findings were further validated with checkerboard, berberine accumulation efflux assays using efflux-related phenotypes and clinical isolates as well as molecular modeling methodology. Conclusions/Significance: These techniques facilitated the direct analysis of the active components from plant extracts, as well as dramatically reduced the time needed to analyze the compounds, without the need for prior isolation. The calculated energetics of the docking poses supported the biological information for the inhibitory capabilities of 4ā€²,5ā€²-ODCQA and furthermore contributed evidence that CQAs show a preferential binding to Major Facilitator Super family efflux systems, a key multidrug resistance determinant in gram-positive bacteria.National Institutes of Health (U.S.) (grant R01GM59903)National Institutes of Health (U.S.) (grant R01AI050875)Netherlands Organization for Scientific Research (VICI grant 700.56.442)Massachusetts Technology Transfer Center (MTTC)National Institutes of Health (U.S.) (grant 5U54MH084690-02

    Plant Antimicrobial Agents and Their Effects on Plant and Human Pathogens

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    To protect themselves, plants accumulate an armoury of antimicrobial secondary metabolites. Some metabolites represent constitutive chemical barriers to microbial attack (phytoanticipins) and others inducible antimicrobials (phytoalexins). They are extensively studied as promising plant and human disease-controlling agents. This review discusses the bioactivity of several phytoalexins and phytoanticipins defending plants against fungal and bacterial aggressors and those with antibacterial activities against pathogens affecting humans such as Pseudomonas aeruginosa and Staphylococcus aureus involved in respiratory infections of cystic fibrosis patients. The utility of plant products as ā€œantibiotic potentiatorsā€ and ā€œvirulence attenuatorsā€ is also described as well as some biotechnological applications in phytoprotection

    Newly rare or newly common: evolutionary feedbacks through changes in population density and relative species abundance, and their management implications

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    Environmental management typically seeks to increase or maintain the population sizes of desirable species and to decrease population sizes of undesirable pests, pathogens, or invaders. With changes in population size come long-recognized changes in ecological processes that act in a density-dependent fashion. While the ecological effects of density dependence have been well studied, the evolutionary effects of changes in population size, via changes in ecological interactions with community members, are underappreciated. Here, we provide examples of changing selective pressures on, or evolution in, species as a result of changes in either density of conspecifics or changes in the frequency of heterospecific versus conspecific interactions. We also discuss the management implications of such evolutionary responses in species that have experienced rapid increases or decreases in density caused by human actions
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