154 research outputs found

    1,8-Cineole Inhibits Both Proliferation and Elongation of BY-2 Cultured Tobacco Cells

    Get PDF
    Volatile monoterpenes such as 1,8-cineole inhibit the growth of Brassica campestris seedlings in a dose-dependent manner, and the growth-inhibitory effects are more severe for roots than hypocotyls. The preferential inhibition of root growth may be explained if the compounds inhibit cell proliferation more severely than cell elongation because root growth requires both elongation and proliferation of the constituent cells, whereas hypocotyl growth depends exclusively on elongation of existing cells. In order to examine this possibility, BY-2 suspension-cultured tobacco (Nicotiana tabacum) cells were treated with 1,8-cineole, and the inhibitory effects on cell proliferation and on cell elongation were assessed quantitatively. Treatment with 1,8-cineole lowered both the mitotic index and elongation of the cells in a dose-dependent manner, and the half-maximal inhibitory concentration (IC50) for cell elongation was lower than that for cell proliferation. Moreover, 1,8-cineole also inhibited starch synthesis, with IC50 lower than that for cell proliferation. Thus, the inhibitory effects of 1,8-cineole were not specific to cell proliferation; rather, 1,8-cineole seemed inhibitory to a variety of physiological activities when it was in direct contact with target cells. Based on these results, possible mechanisms for the mode of action of 1,8-cineole and for its preferential inhibition on root growth are discussed

    Antibiotic sensitivity profile of Salmonella isolated from two slaughterhouses and human clinical cases

    Get PDF
    The antibiotic sensitivity of Salmonella strains isolated during the period 1996-98 from two industrial slaughterhouses of Northern Greece was detennined and compared with that of salmonellae isolated from human hospital cases during the period 1995-1997. For antibiotic sensitivity the disc agar diffusion method was used. Of 1874 samples obtained from the slaughterhouse environment (floors, worker\u27s hands and their knives), pork carcasses, by-products (livers and plucks) as well as lymph nodes and caecal contents 178 (9.5%) were positive for Salmonella spp. The salmonellae belonged to 22 serotypes. S. derby, S. london and S. typhimurium represented 25.8%, 15.2%, and 10.7% of the serotypes respectively. Of the salmonellae 59%, and 4.5%, were resistant and 33%, and 4.5% were intermediate sensitive to Tetracyclin, and Streptomycin, respectively and 26.4%, 14.6%, 5.1%, 1.7% and 1% were resistant to Ampicillin, Sulfamethoxa\u3eole I Trimethoprim, Chloramphenicol, Gentamicin, and Tobramycin respectively. Of the S. typhimurium strains 47% were resistant to Ampicillin and 41.2% to Chloramphenicol. Seven of the 19 strains were DT I 04, isolated for the first time in Greece, and multiple drug resistant. Of all isolates 5.1% were resistant to Chloramphenicol, the use of which is prohibited in food animal veterinary practice. Of the 422 salmonellae isolated at the Hospital of Infectious Diseases in Thessaloniki during the period 1996-98 77.4% were S. enteritidis and 17.7% S. typhimurium. Of the salmonellae isolated during 1995-1997, 76-79 % were resistant to Ampicillin and 1.2-1.5% to Chloramphenicol. Many of S. typhimurium strains isolated from the slaughterhouses and human cases exhibited the same antibiotic sensitivity profile a fact indicative of a potential transfer of animal strains to humans. Salmonellae of the same serotype exhibited different antibiotic resistance profiles, an indication of the presence of different clones within the same serotype. No S. enteritidis was isolated in slaughterhouses

    A bacterial quorum-sensing precursor induces mortality in the marine coccolithophore, Emiliania huxleyi

    Get PDF
    © The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Frontiers in Microbiology 7 (2016): 59, doi:10.3389/fmicb.2016.00059.Interactions between phytoplankton and bacteria play a central role in mediating biogeochemical cycling and food web structure in the ocean. However, deciphering the chemical drivers of these interspecies interactions remains challenging. Here, we report the isolation of 2-heptyl-4-quinolone (HHQ), released by Pseudoalteromonas piscicida, a marine gamma-proteobacteria previously reported to induce phytoplankton mortality through a hitherto unknown algicidal mechanism. HHQ functions as both an antibiotic and a bacterial signaling molecule in cell–cell communication in clinical infection models. Co-culture of the bloom-forming coccolithophore, Emiliania huxleyi with both live P. piscicida and cell-free filtrates caused a significant decrease in algal growth. Investigations of the P. piscicida exometabolome revealed HHQ, at nanomolar concentrations, induced mortality in three strains of E. huxleyi. Mortality of E. huxleyi in response to HHQ occurred slowly, implying static growth rather than a singular loss event (e.g., rapid cell lysis). In contrast, the marine chlorophyte, Dunaliella tertiolecta and diatom, Phaeodactylum tricornutum were unaffected by HHQ exposures. These results suggest that HHQ mediates the type of inter-domain interactions that cause shifts in phytoplankton population dynamics. These chemically mediated interactions, and other like it, ultimately influence large-scale oceanographic processes.This research was support through funding from the Gordon and Betty Moore Foundation through Grant GBMF3301 to MJ and TM; NIH grant from the National Institute of Allergy and Infectious Disease (NIAID – 1R21Al119311-01) to TM and KW; the National Science Foundation (OCE – 1313747) and US National Institute of Environmental Health Science (P01-ES021921) through the Oceans and Human Health Program to BM. Additional financial support was provided to TM from the Flatley Discovery Lab

    Antimicrobial susceptibility of Enterococcus spp. isolated from freshwater fish and personnel and equipment of fish markets in northern Greece

    Get PDF
    Διερευνήθηκε η ευαισθησία στα αντιμικροβιακά φάρμακα και η ικανότητα παραγωγής βιογενών αμινών από στελέχη Enterococcus spp. από ψάρια του γλυκού νερού και το προσωπικό και τον εξοπλισμό ιχθυοπωλείων στη Βόρειο Ελλάδα. Εξετάσθηκαν 270 συνολικά δείγματα και απομονώθηκαν εντερόκοκκοι από 9,6% των δειγμάτων, συγκεκριμένα από 7,4% των δειγμάτων απομονώθηκε Enterococcus faecium και από 2,2% των δειγμάτων απομονώθηκε Enterococcus casseliflavus. Τα απομονωθέντα στελέχη εξετάσθηκαν για την ευαισθησία τους έναντι 20 αντιμικροβιακών ουσιών που χρησιμοποιούνται συνήθως σε ελληνικά νοσοκομεία. Όλα τα στελέχη, εκτός ενός, ήταν πολυανθεκτικά εμφανίζοντας αντοχή σε 7-15 αντιμικροβιακά φάρμακα. Αυξημένη συχνότητα ανθεκτικότητας παρατηρήθηκε στην πενικιλλίνη, στις κεφαλοσπορίνες και στην ερυθρομυκίνη. Σχετικά αυξημένη συχνότητα παρατηρήθηκε στην κινουπριστίνη/δαλφοπριστίνη και τη λινεζολίδη, φάρμακα χρησιμοποιούμενα στη θεραπευτική αγωγή λοιμώξεων από ανθεκτικούς στη βανκομυκίνη εντεροκόκκους. Σε ένα στέλεχος E. faecium και ένα E. casseliflavus παρατηρήθηκε μέτρια ανθεκτικότητα έναντι της βανκομυκίνης. Με εξέταση με πολλαπλή αλυσιδωτή αντίδραση πολυμεράσης (multiplex PCR) των στελεχών E. faecium δεν ανιχνέυτηκαν γονίδια αντοχής στη βανκομυκίνη. Όλα τα στελέχη E. faecium και ένα τρίτο των στελεχών E. casseliflavus είχαν την ικανότητα αποκαρβοξυλίωσης της τυροσίνης, όχι όμως της ιστιδίνης, ορνιθίνης και λυσίνης. Τα αποτελέσματα υποδεικνύουν ότι τα ψάρια του γλυκού νερού και το περιβάλλον των ιχθυοπωλείων αποτελούν πιθανές πηγές διασποράς πολυανθεκτικών στελεχών εντερόκοκκων σε ανθρώπους.In total, 270 samples from freshwater fish and personnel and equipment from retail fish markets in three cities in northern Greece, were examined for presence of antimicrobial resistance and biogenic amine production of Enterococcus spp. strains. Enterococci were isolated from 9.6% of the samples; from 7.4% and 2.2%, respectively, Enterococcus faecium and Enterococcus casseliflavus were recovered. Isolates were tested for antibacterial susceptibility to 20 antibiotics used regularly in Greek hospitals. All isolates except one were multi drug resistant, to 7-15 antibiotics. Increased rates of resistance were recorded to penicillin, cephalosporins and erythromycin. Relatively increased rates were recoreded to quinupristin/casdalfopristin and linezolid, drugs commonly used as treatment options of infections by vancomycin-resistant enterococci. One E. faecium and one E. casseliflavus isolate showed intermediate resistance to vancomycin. Multiplex PCR assay for presence of van genes in E. faecium was negative. All E. faecium isolates and one third of E. casseliflavus isolates were able to decarboxylate tyrosine, but not histidine, ornithine or lysine. The results indicate that freshwater fish and fish markets are potential reservoirs of multi-drug resistant enterococci

    Goblin spider genus Neoxyphinus.

    Get PDF
    75 p. : ill., maps ; 26 cm.The Neotropical spider genus Neoxyphinus Birabén, 1953, is revised, comprising 10 species found from the West Indies to northern Argentina. The genus is characterized by a unique combination of characters, which include the presence of a set of low tubercles or large spikes on the posterior surface of carapace; male endites with an apical, retrolateral excavation bearing a subapical toothlike apophysis; palpal bulb strongly inflated; embolus compact, S-shaped, with large, round ejaculatory opening; epigynal atrium large, with angular lateral corners. The large, round ejaculatory duct may be a synapomorphy of the genus. The genus Hawkeswoodoonops Makhan and Ezzatpanah, 2011, is synonymized with Neoxyphinus and the two species included in that genus are considered as nomina dubia. The monotypic genus Decuana Dumitrescu and Georgescu, 1987, is also synonymized with Neoxyphinus and its type species, D. hispida Dumitrescu and Georgescu, 1987, is transferred to the genus and redescribed. Confirming a hypothesis raised in the literature, Dysderina termitophila Bristowe, 1938, is transferred to Neoxyphinus and recognized as the senior synonym of the type species N. ogloblini Birabén, 1953. Two other species are transferred from Dysderina to Neoxyphinus: D. keyserlingi Simon, 1907, here recognized as the senior synonym of D. rugosa Bristowe, 1938, and D. furtiva Chickering, 1968, of which the male is described for the first time. In addition to the redescription of N. termitophilus, n. comb., N. hispidus, n. comb., N. xyphinoides (Chamberlin and Ivie, 1942), N. keyserlingi, n. comb., and N. furtivus, n. comb., five new species are described: N. petrogoblin Abrahim and Ott, from the Amazon basin in Brazil, Colombia, Ecuador, and Peru; N. gregoblin Abrahim and Santos, from Venezuela; N. axe Abrahim and Brescovit, from Bahia, Brazil; N. boibumba Abrahim and Rheims, from Pará, Brazil; and N. barreirosi Abrahim and Bonaldo, from Brazil, Colombia, Guyana, and Venezuela. With the exception of N. boibumba, known only from males, all new species are described from both sexes

    Antihistamines for Postacute Sequelae of SARS-CoV-2 Infection

    Get PDF
    Postacute sequelae of SARS-CoV2 (PASC) infection is an emerging global health crisis, variably affecting millions worldwide. PASC has no established treatment. We describe 2 cases of PASC in response to opportune administration of over-the-counter antihistamines, with significant improvement in symptoms and ability to perform activities of daily living. Future studies are warranted to understand the potential role of histamine in the pathogenesis of PASC and explore the clinical benefits of antihistamines in the treatment of PASC
    corecore