Sample records for bacterial species dilemma

  1. Bacterial communities in the phylloplane of Prunus species.

    PubMed

    Jo, Yeonhwa; Cho, Jin Kyong; Choi, Hoseong; Chu, Hyosub; Lian, Sen; Cho, Won Kyong

    2015-04-01

    Bacterial populations in the phylloplane of four different Prunus species were investigated by 16 S rRNA pyrosequencing. Bioinformatic analysis identified an average of 510 operational taxonomic units belonging to 159 genera in 76 families. The two genera, Sphingomonas and Methylobacterium, were dominant in the phylloplane of four Prunus species. Twenty three genera were commonly identified in the four Prunus species, indicating a high level of bacterial diversity dependent on the plant species. Our study based on 16 S rRNA sequencing reveals the complexity of bacterial diversity in the phylloplane of Prunus species in detail. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Distinct antimicrobial peptide expression determines host species-specific bacterial associations

    PubMed Central

    Franzenburg, Sören; Walter, Jonas; Künzel, Sven; Wang, Jun; Baines, John F.; Bosch, Thomas C. G.; Fraune, Sebastian

    2013-01-01

    Animals are colonized by coevolved bacterial communities, which contribute to the host’s health. This commensal microbiota is often highly specific to its host-species, inferring strong selective pressures on the associated microbes. Several factors, including diet, mucus composition, and the immune system have been proposed as putative determinants of host-associated bacterial communities. Here we report that species-specific antimicrobial peptides account for different bacterial communities associated with closely related species of the cnidarian Hydra. Gene family extensions for potent antimicrobial peptides, the arminins, were detected in four Hydra species, with each species possessing a unique composition and expression profile of arminins. For functional analysis, we inoculated arminin-deficient and control polyps with bacterial consortia characteristic for different Hydra species and compared their selective preferences by 454 pyrosequencing of the bacterial microbiota. In contrast to control polyps, arminin-deficient polyps displayed decreased potential to select for bacterial communities resembling their native microbiota. This finding indicates that species-specific antimicrobial peptides shape species-specific bacterial associations. PMID:24003149

  3. Bacterial Responses to Reactive Chlorine Species

    PubMed Central

    Gray, Michael J.; Wholey, Wei-Yun; Jakob, Ursula

    2013-01-01

    Hypochlorous acid (HOCl), the active ingredient of household bleach, is the most common disinfectant in medical, industrial, and domestic use and plays an important role in microbial killing in the innate immune system. Given the critical importance of the antimicrobial properties of chlorine to public health, it is surprising how little is known about the ways in which bacteria sense and respond to reactive chlorine species (RCS). Although the literature on bacterial responses to reactive oxygen species (ROS) is enormous, work addressing bacterial responses to RCS has begun only recently. Transcriptomic and proteomic studies now provide new insights into how bacteria mount defenses against this important class of antimicrobial compounds. In this review, we summarize the current knowledge, emphasizing the overlaps between RCS stress responses and other more well-characterized bacterial defense systems, and identify outstanding questions that represent productive avenues for future research. PMID:23768204

  4. Eradication of bacterial species via photosensitization

    NASA Astrophysics Data System (ADS)

    Golding, Paul S.; Maddocks, L.; King, Terence A.; Drucker, D. B.

    1999-02-01

    Photosensitization and inactivation efficacy of three bacterial species: Prevotella nigrescens, Staphylococcus aureus and Escherichia coli have been investigated. Samples of Staphylococcus aureus and Escherichia coli were treated with the triphenylmethane dye malachite green isothiocyanate and exposed to light from a variety of continuous and pulsed light sauces at a wavelength of approximately 630 nm. Inactivation of the Gram-positive species Staphylococcus aureus was found to increase with radiation dose, whilst Gram-negative Escherichia coli was resistant to such treatment. Samples of the pigmented species Prevotella nigrescens were found to be inactivated by exposure to light alone. The mechanism of photosensitization and inactivation of Staphylococcus aureus with malachite green isothiocyanate is addressed. The possible roles of the excited triplet state of the photosensitizer, the involvement of molecular oxygen, and the bacterial cell wall are discussed. Photosensitization may provide a way of eliminating naturally pigmented species responsible for a variety of infections, including oral diseases such as gingivitis and periodontitis.

  5. Structural differences in the bacterial flagellar motor among bacterial species.

    PubMed

    Terashima, Hiroyuki; Kawamoto, Akihiro; Morimoto, Yusuke V; Imada, Katsumi; Minamino, Tohru

    2017-01-01

    The bacterial flagellum is a supramolecular motility machine consisting of the basal body as a rotary motor, the hook as a universal joint, and the filament as a helical propeller. Intact structures of the bacterial flagella have been observed for different bacterial species by electron cryotomography and subtomogram averaging. The core structures of the basal body consisting of the C ring, the MS ring, the rod and the protein export apparatus, and their organization are well conserved, but novel and divergent structures have also been visualized to surround the conserved structure of the basal body. This suggests that the flagellar motors have adapted to function in various environments where bacteria live and survive. In this review, we will summarize our current findings on the divergent structures of the bacterial flagellar motor.

  6. Characterisation of the gill mucosal bacterial communities of four butterflyfish species: a reservoir of bacterial diversity in coral reef ecosystems.

    PubMed

    Reverter, Miriam; Sasal, Pierre; Tapissier-Bontemps, N; Lecchini, D; Suzuki, M

    2017-06-01

    While recent studies have suggested that fish mucus microbiota play an important role in homeostasis and prevention of infections, very few studies have investigated the bacterial communities of gill mucus. We characterised the gill mucus bacterial communities of four butterflyfish species and although the bacterial diversity of gill mucus varied significantly between species, Shannon diversities were high (H = 3.7-5.7) in all species. Microbiota composition differed between butterflyfishes, with Chaetodon lunulatus and C. ornatissimus having the most similar bacterial communities, which differed significantly from C. vagabundus and C. reticulatus. The core bacterial community of all species consisted of mainly Proteobacteria followed by Actinobacteria and Firmicutes. Chaetodonlunulatus and C. ornatissimus bacterial communities were mostly dominated by Gammaproteobacteria with Vibrio as the most abundant genus. Chaetodonvagabundus and C. reticulatus presented similar abundances of Gammaproteobacteria and Alphaproteobacteria, which were well represented by Acinetobacter and Paracoccus, respectively. In conclusion, our results indicate that different fish species present specific bacterial assemblages. Finally, as mucus layers are nutrient hotspots for heterotrophic bacteria living in oligotrophic environments, such as coral reef waters, the high bacterial diversity found in butterflyfish gill mucus might indicate external fish mucus surfaces act as a reservoir of coral reef bacterial diversity. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  7. Panamanian frog species host unique skin bacterial communities

    PubMed Central

    Belden, Lisa K.; Hughey, Myra C.; Rebollar, Eria A.; Umile, Thomas P.; Loftus, Stephen C.; Burzynski, Elizabeth A.; Minbiole, Kevin P. C.; House, Leanna L.; Jensen, Roderick V.; Becker, Matthew H.; Walke, Jenifer B.; Medina, Daniel; Ibáñez, Roberto; Harris, Reid N.

    2015-01-01

    Vertebrates, including amphibians, host diverse symbiotic microbes that contribute to host disease resistance. Globally, and especially in montane tropical systems, many amphibian species are threatened by a chytrid fungus, Batrachochytrium dendrobatidis (Bd), that causes a lethal skin disease. Bd therefore may be a strong selective agent on the diversity and function of the microbial communities inhabiting amphibian skin. In Panamá, amphibian population declines and the spread of Bd have been tracked. In 2012, we completed a field survey in Panamá to examine frog skin microbiota in the context of Bd infection. We focused on three frog species and collected two skin swabs per frog from a total of 136 frogs across four sites that varied from west to east in the time since Bd arrival. One swab was used to assess bacterial community structure using 16S rRNA amplicon sequencing and to determine Bd infection status, and one was used to assess metabolite diversity, as the bacterial production of anti-fungal metabolites is an important disease resistance function. The skin microbiota of the three Panamanian frog species differed in OTU (operational taxonomic unit, ~bacterial species) community composition and metabolite profiles, although the pattern was less strong for the metabolites. Comparisons between frog skin bacterial communities from Panamá and the US suggest broad similarities at the phylum level, but key differences at lower taxonomic levels. In our field survey in Panamá, across all four sites, only 35 individuals (~26%) were Bd infected. There was no clustering of OTUs or metabolite profiles based on Bd infection status and no clear pattern of west-east changes in OTUs or metabolite profiles across the four sites. Overall, our field survey data suggest that different bacterial communities might be producing broadly similar sets of metabolites across frog hosts and sites. Community structure and function may not be as tightly coupled in these skin symbiont

  8. Distinctive bacterial communities in the rhizoplane of four tropical tree species.

    PubMed

    Oh, Yoon Myung; Kim, Mincheol; Lee-Cruz, Larisa; Lai-Hoe, Ang; Go, Rusea; Ainuddin, N; Rahim, Raha Abdul; Shukor, Noraini; Adams, Jonathan M

    2012-11-01

    It is known that the microbial community of the rhizosphere is not only influenced by factors such as root exudates, phenology, and nutrient uptake but also by the plant species. However, studies of bacterial communities associated with tropical rainforest tree root surfaces, or rhizoplane, are lacking. Here, we analyzed the bacterial community of root surfaces of four species of native trees, Agathis borneensis, Dipterocarpus kerrii, Dyera costulata, and Gnetum gnemon, and nearby bulk soils, in a rainforest arboretum in Malaysia, using 454 pyrosequencing of the 16S rRNA gene. The rhizoplane bacterial communities for each of the four tree species sampled clustered separately from one another on an ordination, suggesting that these assemblages are linked to chemical and biological characteristics of the host or possibly to the mycorrhizal fungi present. Bacterial communities of the rhizoplane had various similarities to surrounding bulk soils. Acidobacteria, Alphaproteobacteria, and Betaproteobacteria were dominant in rhizoplane communities and in bulk soils from the same depth (0-10 cm). In contrast, the relative abundance of certain bacterial lineages on the rhizoplane was different from that in bulk soils: Bacteroidetes and Betaproteobacteria, which are known as copiotrophs, were much more abundant in the rhizoplane in comparison to bulk soil. At the genus level, Burkholderia, Acidobacterium, Dyella, and Edaphobacter were more abundant in the rhizoplane. Burkholderia, which are known as both pathogens and mutualists of plants, were especially abundant on the rhizoplane of all tree species sampled. The Burkholderia species present included known mutualists of tropical crops and also known N fixers. The host-specific character of tropical tree rhizoplane bacterial communities may have implications for understanding nutrient cycling, recruitment, and structuring of tree species diversity in tropical forests. Such understanding may prove to be useful in both

  9. Towards large-scale FAME-based bacterial species identification using machine learning techniques.

    PubMed

    Slabbinck, Bram; De Baets, Bernard; Dawyndt, Peter; De Vos, Paul

    2009-05-01

    In the last decade, bacterial taxonomy witnessed a huge expansion. The swift pace of bacterial species (re-)definitions has a serious impact on the accuracy and completeness of first-line identification methods. Consequently, back-end identification libraries need to be synchronized with the List of Prokaryotic names with Standing in Nomenclature. In this study, we focus on bacterial fatty acid methyl ester (FAME) profiling as a broadly used first-line identification method. From the BAME@LMG database, we have selected FAME profiles of individual strains belonging to the genera Bacillus, Paenibacillus and Pseudomonas. Only those profiles resulting from standard growth conditions have been retained. The corresponding data set covers 74, 44 and 95 validly published bacterial species, respectively, represented by 961, 378 and 1673 standard FAME profiles. Through the application of machine learning techniques in a supervised strategy, different computational models have been built for genus and species identification. Three techniques have been considered: artificial neural networks, random forests and support vector machines. Nearly perfect identification has been achieved at genus level. Notwithstanding the known limited discriminative power of FAME analysis for species identification, the computational models have resulted in good species identification results for the three genera. For Bacillus, Paenibacillus and Pseudomonas, random forests have resulted in sensitivity values, respectively, 0.847, 0.901 and 0.708. The random forests models outperform those of the other machine learning techniques. Moreover, our machine learning approach also outperformed the Sherlock MIS (MIDI Inc., Newark, DE, USA). These results show that machine learning proves very useful for FAME-based bacterial species identification. Besides good bacterial identification at species level, speed and ease of taxonomic synchronization are major advantages of this computational species

  10. Distribution of 10 periodontal bacterial species in children and adolescents over a 7-year period.

    PubMed

    Nakano, K; Miyamoto, E; Tamura, K; Nemoto, H; Fujita, K; Nomura, R; Ooshima, T

    2008-10-01

    There is scant information available regarding the distribution of periodontal bacterial species in children and adolescents over an extended period. The purpose of this study was to compare bacterial profiles in the same individuals over a period of 7 years. Twenty-six children and adolescents from whom dental plaque and saliva specimens were obtained during both the first (1999-2000) and second (2006-2007) periods, were analyzed. Bacterial DNA was extracted from each specimen and the presence of 10 periodontal bacterial species was determined using a PCR method, with a focus on the red complex species of Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia. Subjects with red complex species in saliva specimens obtained during the second collection possessed a significantly higher number of total bacterial species than those without. The detection rate of the red complex species in the second collection period samples was significantly greater in subjects who had two or more species detected in samples taken during the first collection compared with the other subjects. Subjects possessing red complex species may be at possible risk for infection with a high number of periodontal bacterial species during adolescent and younger adult years.

  11. New bacterial species associated with chronic periodontitis.

    PubMed

    Kumar, P S; Griffen, A L; Barton, J A; Paster, B J; Moeschberger, M L; Leys, E J

    2003-05-01

    Recent investigations of the human subgingival oral flora based on ribosomal 16S cloning and sequencing have shown many of the bacterial species present to be novel species or phylotypes. The purpose of the present investigation was to identify potential periodontal pathogens among these newly identified species and phylotypes. Species-specific ribosomal 16S primers for PCR amplification were developed for detection of new species. Associations with chronic periodontitis were observed for several new species or phylotypes, including uncultivated clones D084 and BH017 from the Deferribacteres phylum, AU126 from the Bacteroidetes phylum, Megasphaera clone BB166, clone X112 from the OP11 phylum, and clone I025 from the TM7 phylum, and the named species Eubacterium saphenum, Porphyromonas endodontalis, Prevotella denticola, and Cryptobacterium curtum. Species or phylotypes more prevalent in periodontal health included two uncultivated phylotypes, clone W090 from the Deferribacteres phylum and clone BU063 from the Bacteroidetes, and named species Atopobium rimae and Atopobium parvulum.

  12. Bacterial-biota dynamics of eight bryophyte species from different ecosystems

    PubMed Central

    Koua, Faisal Hammad Mekky; Kimbara, Kazuhide; Tani, Akio

    2014-01-01

    Despite the importance of bryophyte-associated microorganisms in various ecological aspects including their crucial roles in the soil-enrichment of organic mass and N2 fixation, nonetheless, little is known about the microbial diversity of the bryophyte phyllospheres (epi-/endophytes). To get insights into bacterial community structures and their dynamics on the bryophyte habitats in different ecosystems and their potential biological roles, we utilized the 16S rRNA gene PCR-DGGE and subsequent phylogenetic analyses to investigate the bacterial community of eight bryophyte species collected from three distinct ecosystems from western Japan. Forty-two bacterial species belonging to γ-proteobacteria and Firmicutes with 71.4% and 28.6%, respectively, were identified among 90 DGGE gel band population. These DGGE-bands were assigned to 13 different genera with obvious predomination the genus Clostridium with 21.4% from the total bacterial community. These analyses provide new insights into bryophyte-associated bacteria and their relations to the ecosystems. PMID:25737654

  13. A new mathematical model of bacterial interactions in two-species oral biofilms

    PubMed Central

    Martin, Bénédicte; Tamanai-Shacoori, Zohreh; Bronsard, Julie; Ginguené, Franck; Meuric, Vincent

    2017-01-01

    Periodontitis are bacterial inflammatory diseases, where the bacterial biofilms present on the tooth-supporting tissues switch from a healthy state towards a pathogenic state. Among bacterial species involved in the disease, Porphyromonas gingivalis has been shown to induce dysbiosis, and to induce virulence of otherwise healthy bacteria like Streptococcus gordonii. During biofilm development, primary colonizers such as S. gordonii first attach to the surface and allow the subsequent adhesion of periodontal pathogens such as P. gingivalis. Interactions between those two bacteria have been extensively studied during the adhesion step of the biofilm. The aim of the study was to understand interactions of both species during the growing phase of the biofilm, for which little knowledge is available, using a mathematical model. This two-species biofilm model was based on a substrate-dependent growth, implemented with damage parameters, and validated thanks to data obtained on experimental biofilms. Three different hypothesis of interactions were proposed and assayed using this model: independence, competition between both bacteria species, or induction of toxicity by one species for the other species. Adequacy between experimental and simulated biofilms were found with the last hypothetic mathematical model. This new mathematical model of two species bacteria biofilms, dependent on different substrates for growing, can be applied to any bacteria species, environmental conditions, or steps of biofilm development. It will be of great interest for exploring bacterial interactions in biofilm conditions. PMID:28253369

  14. Prevalent bacterial species and novel phylotypes in advanced noma lesions.

    PubMed

    Paster, B J; Falkler Jr, W A; Enwonwu, C O; Idigbe, E O; Savage, K O; Levanos, V A; Tamer, M A; Ericson, R L; Lau, C N; Dewhirst, F E

    2002-06-01

    The purpose of this study was to determine the bacterial diversity in advanced noma lesions using culture-independent molecular methods. 16S ribosomal DNA bacterial genes from DNA isolated from advanced noma lesions of four Nigerian children were PCR amplified with universally conserved primers and spirochetal selective primers and cloned into Escherichia coli. Partial 16S rRNA sequences of approximately 500 bases from 212 cloned inserts were used initially to determine species identity or closest relatives by comparison with sequences of known species or phylotypes. Nearly complete sequences of approximately 1,500 bases were obtained for most of the potentially novel species. A total of 67 bacterial species or phylotypes were detected, 25 of which have not yet been grown in vitro. Nineteen of the species or phylotypes, including Propionibacterium acnes, Staphylococcus spp., and the opportunistic pathogens Stenotrophomonas maltophilia and Ochrobactrum anthropi were detected in more than one subject. Other known species that were detected included Achromobacter spp., Afipia spp., Brevundimonas diminuta, Capnocytophaga spp., Cardiobacterium sp., Eikenella corrodens, Fusobacterium spp., Gemella haemoylsans, and Neisseria spp. Phylotypes that were unique to noma infections included those in the genera Eubacterium, Flavobacterium, Kocuria, Microbacterium, and Porphyromonas and the related Streptococcus salivarius and genera Sphingomonas and TREPONEMA: Since advanced noma lesions are infections open to the environment, it was not surprising to detect species not commonly associated with the oral cavity, e.g., from soil. Several species previously implicated as putative pathogens of noma, such as spirochetes and Fusobacterium spp., were detected in at least one subject. However, due to the limited number of available noma subjects, it was not possible at this time to associate specific species with the disease.

  15. The bacterial species definition in the genomic era

    PubMed Central

    Konstantinidis, Konstantinos T; Ramette, Alban; Tiedje, James M

    2006-01-01

    The bacterial species definition, despite its eminent practical significance for identification, diagnosis, quarantine and diversity surveys, remains a very difficult issue to advance. Genomics now offers novel insights into intra-species diversity and the potential for emergence of a more soundly based system. Although we share the excitement, we argue that it is premature for a universal change to the definition because current knowledge is based on too few phylogenetic groups and too few samples of natural populations. Our analysis of five important bacterial groups suggests, however, that more stringent standards for species may be justifiable when a solid understanding of gene content and ecological distinctiveness becomes available. Our analysis also reveals what is actually encompassed in a species according to the current standards, in terms of whole-genome sequence and gene-content diversity, and shows that this does not correspond to coherent clusters for the environmental Burkholderia and Shewanella genera examined. In contrast, the obligatory pathogens, which have a very restricted ecological niche, do exhibit clusters. Therefore, the idea of biologically meaningful clusters of diversity that applies to most eukaryotes may not be universally applicable in the microbial world, or if such clusters exist, they may be found at different levels of distinction. PMID:17062412

  16. Predominant bacterial species in subgingival plaque in dogs.

    PubMed

    Dahlén, G; Charalampakis, G; Abrahamsson, I; Bengtsson, L; Falsen, E

    2012-06-01

    The dog has been used extensively for experimental and microbiological studies on periodontitis and peri-implantitis without detailed knowledge about the predominant flora of the subgingival plaque. This study was designed to evaluate the predominant cultivable bacterial species in dogs and compare them phenotypically and genotypically with corresponding human species. Four subgingival samples were taken from two upper premolars in each of six Labrador retrievers. The samples from each dog were processed for anaerobic culture. From the samples of each dog, the five or six predominating bacteria based on colony morphology were selected and pure cultured. Each of the strains was characterized by Gram stain, anaerobic/aerobic growth and API-ZYM test. Eighteen strains showing clear-cut phenotypic differences were further classified based on DNA sequencing technology. Cross-reactions of DNA probes from human and dog strains were also tested against a panel of both human and dog bacterial species. Thirty-one strains in the dogs were isolated and characterized. They represented 21 different species, of which six belonged to the genus Porphyromonas. No species was found consistently in the predominant flora of all six dogs. Porphyromonas crevioricanis and Fusobacterium canifelinum were the two most prevalent species in predominant flora in dogs. DNA probes from human and dog species cross-reacted to some extent with related strains from humans and dogs; however, distinct exceptions were found. The predominant cultural subgingival flora in dogs shows great similarities with the subgingival bacteria from humans at the genus level, but distinct differences at the species level; however, a genetic relatedness could be disclosed for most strains investigated. © 2011 John Wiley & Sons A/S.

  17. Recombination-Driven Genome Evolution and Stability of Bacterial Species.

    PubMed

    Dixit, Purushottam D; Pang, Tin Yau; Maslov, Sergei

    2017-09-01

    While bacteria divide clonally, horizontal gene transfer followed by homologous recombination is now recognized as an important contributor to their evolution. However, the details of how the competition between clonality and recombination shapes genome diversity remains poorly understood. Using a computational model, we find two principal regimes in bacterial evolution and identify two composite parameters that dictate the evolutionary fate of bacterial species. In the divergent regime, characterized by either a low recombination frequency or strict barriers to recombination, cohesion due to recombination is not sufficient to overcome the mutational drift. As a consequence, the divergence between pairs of genomes in the population steadily increases in the course of their evolution. The species lacks genetic coherence with sexually isolated clonal subpopulations continuously formed and dissolved. In contrast, in the metastable regime, characterized by a high recombination frequency combined with low barriers to recombination, genomes continuously recombine with the rest of the population. The population remains genetically cohesive and temporally stable. Notably, the transition between these two regimes can be affected by relatively small changes in evolutionary parameters. Using the Multi Locus Sequence Typing (MLST) data, we classify a number of bacterial species to be either the divergent or the metastable type. Generalizations of our framework to include selection, ecologically structured populations, and horizontal gene transfer of nonhomologous regions are discussed as well. Copyright © 2017 by the Genetics Society of America.

  18. Bacterial Communities of Diverse Drosophila Species: Ecological Context of a Host–Microbe Model System

    PubMed Central

    Bhatnagar, Srijak; Eisen, Jonathan A.; Kopp, Artyom

    2011-01-01

    Drosophila melanogaster is emerging as an important model of non-pathogenic host–microbe interactions. The genetic and experimental tractability of Drosophila has led to significant gains in our understanding of animal–microbial symbiosis. However, the full implications of these results cannot be appreciated without the knowledge of the microbial communities associated with natural Drosophila populations. In particular, it is not clear whether laboratory cultures can serve as an accurate model of host–microbe interactions that occur in the wild, or those that have occurred over evolutionary time. To fill this gap, we characterized natural bacterial communities associated with 14 species of Drosophila and related genera collected from distant geographic locations. To represent the ecological diversity of Drosophilids, examined species included fruit-, flower-, mushroom-, and cactus-feeders. In parallel, wild host populations were compared to laboratory strains, and controlled experiments were performed to assess the importance of host species and diet in shaping bacterial microbiome composition. We find that Drosophilid flies have taxonomically restricted bacterial communities, with 85% of the natural bacterial microbiome composed of only four bacterial families. The dominant bacterial taxa are widespread and found in many different host species despite the taxonomic, ecological, and geographic diversity of their hosts. Both natural surveys and laboratory experiments indicate that host diet plays a major role in shaping the Drosophila bacterial microbiome. Despite this, the internal bacterial microbiome represents only a highly reduced subset of the external bacterial communities, suggesting that the host exercises some level of control over the bacteria that inhabit its digestive tract. Finally, we show that laboratory strains provide only a limited model of natural host–microbe interactions. Bacterial taxa used in experimental studies are rare or absent in

  19. Dilemma of dilemmas: how collective and individual perspectives can clarify the size dilemma in voluntary linear public goods dilemmas.

    PubMed

    Shank, Daniel B; Kashima, Yoshihisa; Saber, Saam; Gale, Thomas; Kirley, Michael

    2015-01-01

    Empirical findings on public goods dilemmas indicate an unresolved dilemma: that increasing size-the number of people in the dilemma-sometimes increases, decreases, or does not influence cooperation. We clarify this dilemma by first classifying public goods dilemma properties that specify individual outcomes as individual properties (e.g., Marginal Per Capita Return) and group outcomes as group properties (e.g., public good multiplier), mathematically showing how only one set of properties can remain constant as the dilemma size increases. Underpinning decision-making regarding individual and group properties, we propose that individuals are motivated by both individual and group preferences based on a theory of collective rationality. We use Van Lange's integrated model of social value orientations to operationalize these preferences as an amalgamation of outcomes for self, outcomes for others, and equality of outcomes. Based on this model, we then predict how the public good's benefit and size, combined with controlling individual versus group properties, produce different levels of cooperation in public goods dilemmas. A two (low vs. high benefit) by three (2-person baseline vs. 5-person holding constant individual properties vs. 5-person holding constant group properties) factorial experiment (group n = 99; participant n = 390) confirms our hypotheses. The results indicate that when holding constant group properties, size decreases cooperation. Yet when holding constant individual properties, size increases cooperation when benefit is low and does not affect cooperation when benefit is high. Using agent-based simulations of individual and group preferences vis-à-vis the integrative model, we fit a weighted simulation model to the empirical data. This fitted model is sufficient to reproduce the empirical results, but only when both individual (self-interest) and group (other-interest and equality) preference are included. Our research contributes to

  20. Association between Lactobacillus species and bacterial vaginosis-related bacteria, and bacterial vaginosis scores in pregnant Japanese women

    PubMed Central

    Tamrakar, Renuka; Yamada, Takashi; Furuta, Itsuko; Cho, Kazutoshi; Morikawa, Mamoru; Yamada, Hideto; Sakuragi, Noriaki; Minakami, Hisanori

    2007-01-01

    Background Bacterial vaginosis (BV), the etiology of which is still uncertain, increases the risk of preterm birth. Recent PCR-based studies suggested that BV is associated with complex vaginal bacterial communities, including many newly recognized bacterial species in non-pregnant women. Methods To examine whether these bacteria are also involved in BV in pregnant Japanese women, vaginal fluid samples were taken from 132 women, classified as normal (n = 98), intermediate (n = 21), or BV (n = 13) using the Nugent gram stain criteria, and studied. DNA extracted from these samples was analyzed for bacterial sequences of any Lactobacillus, four Lactobacillus species, and four BV-related bacteria by PCR with primers for 16S ribosomal DNA including a universal Lactobacillus primer, Lactobacillus species-specific primers for L. crispatus, L. jensenii, L. gasseri, and L. iners, and BV-related bacterium-specific primers for BVAB2, Megasphaera, Leptotrichia, and Eggerthella-like bacterium. Results The prevalences of L. crispatus, L. jensenii, and L. gasseri were significantly higher, while those of BVAB2, Megasphaera, Leptotrichia, and Eggerthella-like bacterium were significantly lower in the normal group than in the BV group. Unlike other Lactobacillus species, the prevalence of L. iners did not differ between the three groups and women with L. iners were significantly more likely to have BVAB2, Megasphaera, Leptotrichia, and Eggerthella-like bacterium. Linear regression analysis revealed associations of BVAB2 and Megasphaera with Nugent score, and multivariate regression analyses suggested a close relationship between Eggerthella-like bacterium and BV. Conclusion The BV-related bacteria, including BVAB2, Megasphaera, Leptotrichia, and Eggerthella-like bacterium, are common in the vagina of pregnant Japanese women with BV. The presence of L. iners may be correlated with vaginal colonization by these BV-related bacteria. PMID:17986357

  1. Coral-associated bacterial diversity is conserved across two deep-sea Anthothela species

    USGS Publications Warehouse

    Lawler, Stephanie N.; Kellogg, Christina A.; France, Scott C; Clostio, Rachel W; Brooke, Sandra D.; Ross, Steve W.

    2016-01-01

    Cold-water corals, similar to tropical corals, contain diverse and complex microbial assemblages. These bacteria provide essential biological functions within coral holobionts, facilitating increased nutrient utilization and production of antimicrobial compounds. To date, few cold-water octocoral species have been analyzed to explore the diversity and abundance of their microbial associates. For this study, 23 samples of the family Anthothelidae were collected from Norfolk (n = 12) and Baltimore Canyons (n = 11) from the western Atlantic in August 2012 and May 2013. Genetic testing found that these samples comprised two Anthothela species (Anthothela grandiflora and Anthothela sp.) and Alcyonium grandiflorum. DNA was extracted and sequenced with primers targeting the V4-V5 variable region of the 16S rRNA gene using 454 pyrosequencing with GS FLX Titanium chemistry. Results demonstrated that the coral host was the primary driver of bacterial community composition. Al. grandiflorum, dominated by Alteromonadales and Pirellulales had much higher species richness, and a distinct bacterial community compared to Anthothela samples. Anthothela species (A. grandiflora and Anthothela sp.) had very similar bacterial communities, dominated by Oceanospirillales and Spirochaetes. Additional analysis of core-conserved bacteria at 90% sample coverage revealed genus level conservation across Anthothela samples. This core included unclassified Oceanospirillales, Kiloniellales, Campylobacterales, and genus Spirochaeta. Members of this core were previously recognized for their functional capabilities in nitrogen cycling and suggest the possibility of a nearly complete nitrogen cycle within Anthothela species. Overall, many of the bacterial associates identified in this study have the potential to contribute to the acquisition and cycling of nutrients within the coral holobiont.

  2. Plants of the fynbos biome harbour host species-specific bacterial communities.

    PubMed

    Miyambo, Tsakani; Makhalanyane, Thulani P; Cowan, Don A; Valverde, Angel

    2016-08-01

    The fynbos biome in South Africa is globally recognised as a plant biodiversity hotspot. However, very little is known about the bacterial communities associated with fynbos plants, despite interactions between primary producers and bacteria having an impact on the physiology of both partners and shaping ecosystem diversity. This study reports on the structure, phylogenetic composition and potential roles of the endophytic bacterial communities located in the stems of three fynbos plants (Erepsia anceps, Phaenocoma prolifera and Leucadendron laureolum). Using Illumina MiSeq 16S rRNA sequencing we found that different subpopulations of Deinococcus-Thermus, Alphaproteobacteria, Acidobacteria and Firmicutes dominated the endophytic bacterial communities. Alphaproteobacteria and Actinobacteria were prevalent in P. prolifera, whereas Deinococcus-Thermus dominated in L. laureolum, revealing species-specific host-bacteria associations. Although a high degree of variability in the endophytic bacterial communities within hosts was observed, we also detected a core microbiome across the stems of the three plant species, which accounted for 72% of the sequences. Altogether, it seems that both deterministic and stochastic processes shaped microbial communities. Endophytic bacterial communities harboured putative plant growth-promoting bacteria, thus having the potential to influence host health and growth. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  3. Development of a Single Locus Sequence Typing (SLST) Scheme for Typing Bacterial Species Directly from Complex Communities.

    PubMed

    Scholz, Christian F P; Jensen, Anders

    2017-01-01

    The protocol describes a computational method to develop a Single Locus Sequence Typing (SLST) scheme for typing bacterial species. The resulting scheme can be used to type bacterial isolates as well as bacterial species directly from complex communities using next-generation sequencing technologies.

  4. Bacterial Communities in the Rhizospheres of Three Mangrove Tree Species from Beilun Estuary, China.

    PubMed

    Wu, Peng; Xiong, Xiaofei; Xu, Zhanzhou; Lu, Chuqian; Cheng, Hao; Lyu, Xiangli; Zhang, Jinghuai; He, Wei; Deng, Wei; Lyu, Yihua; Lou, Quansheng; Hong, Yiguo; Fang, Hongda

    2016-01-01

    The bacterial communities played important roles in the high productivity mangrove ecosystem. In this study, we investigated the vertical distributions of rhizosphere bacteria from three mangrove species (Bruguiera gymnorrhiza, Kandelia candel and Aegiceras corniculatum) in Beilun Estuary, China using high throughput DNA pyrosequencing of the 16S rRNA gene. Phylogenetic analysis showed that bacterial communities from mangrove rhizosphere sediments were dominated by Proteobacteria (mostly Deltaproteobacteria and Gammaproteobacteria), followed by Chloroflexi, Bacteroidetes, Planctomycetes and Acidobacteria. However, the ANOVA analysis on Shannon and Chao1 indices indicated that bacterial communities among sediments of the three mangrove species varied more strongly than the sampling depths. In addition, the PCA result demonstrated that the bacterial communities could be separated into three groups according to the mangrove species. Moreover, the dominated orders Rhodospirillales, GCA004 and envOPS12 were significantly different among sediments of the three mangrove species. The results of this study provided valuable information about the distribution feature of rhizosphere bacteria from Chinese mangrove plants and shed insights into biogeochemical transformations driven by bacteria in rhizosphere sediments.

  5. Bacterial Communities in the Rhizospheres of Three Mangrove Tree Species from Beilun Estuary, China

    PubMed Central

    Wu, Peng; Xiong, Xiaofei; Xu, Zhanzhou; Lu, Chuqian; Cheng, Hao; Lyu, Xiangli; Zhang, Jinghuai; He, Wei; Deng, Wei; Lyu, Yihua; Lou, Quansheng; Hong, Yiguo; Fang, Hongda

    2016-01-01

    The bacterial communities played important roles in the high productivity mangrove ecosystem. In this study, we investigated the vertical distributions of rhizosphere bacteria from three mangrove species (Bruguiera gymnorrhiza, Kandelia candel and Aegiceras corniculatum) in Beilun Estuary, China using high throughput DNA pyrosequencing of the 16S rRNA gene. Phylogenetic analysis showed that bacterial communities from mangrove rhizosphere sediments were dominated by Proteobacteria (mostly Deltaproteobacteria and Gammaproteobacteria), followed by Chloroflexi, Bacteroidetes, Planctomycetes and Acidobacteria. However, the ANOVA analysis on Shannon and Chao1 indices indicated that bacterial communities among sediments of the three mangrove species varied more strongly than the sampling depths. In addition, the PCA result demonstrated that the bacterial communities could be separated into three groups according to the mangrove species. Moreover, the dominated orders Rhodospirillales, GCA004 and envOPS12 were significantly different among sediments of the three mangrove species. The results of this study provided valuable information about the distribution feature of rhizosphere bacteria from Chinese mangrove plants and shed insights into biogeochemical transformations driven by bacteria in rhizosphere sediments. PMID:27695084

  6. Diazotrophic potential among bacterial communities associated with wild and cultivated Agave species.

    PubMed

    Desgarennes, Damaris; Garrido, Etzel; Torres-Gomez, Miryam J; Peña-Cabriales, Juan J; Partida-Martinez, Laila P

    2014-12-01

    Agaves are major biotic resources in arid and semi-arid ecosystems. Despite their ecological, economical and cultural relevance, many aspects of the microbial communities associated with agaves are still unknown. Here, we investigated the bacterial communities associated with two Agave species by 16S rRNA- Denaturing gradient gel electrophoresis fingerprinting and sequencing. We also evaluated the effects of biotic and abiotic factors in the structure of the bacterial communities. In parallel, we isolated and characterized diazotrophic bacteria associated with agaves, as Agave soils are characterized by their low nitrogen content. Our results demonstrate that in Agave, the structure of prokaryotic assemblages was mostly influenced by the community group, where the soil, episphere, and endosphere were clearly distinct. Proteobacteria (γ and α), Actinobacteria, and Acidobacteria were the dominant phyla. Bacterial communities in the episphere of agaves were mainly influenced by the host species, whereas in the endosphere were affected by the season. Fifteen bacterial taxa were common and abundant in the endosphere of both Agave species during the dry season. Notably, some of the confirmed diazotrophic strains belonged to this group, suggesting a possible beneficial role in planta. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  7. Coral-Associated Bacterial Diversity Is Conserved across Two Deep-Sea Anthothela Species

    PubMed Central

    Lawler, Stephanie N.; Kellogg, Christina A.; France, Scott C.; Clostio, Rachel W.; Brooke, Sandra D.; Ross, Steve W.

    2016-01-01

    Cold-water corals, similar to tropical corals, contain diverse and complex microbial assemblages. These bacteria provide essential biological functions within coral holobionts, facilitating increased nutrient utilization and production of antimicrobial compounds. To date, few cold-water octocoral species have been analyzed to explore the diversity and abundance of their microbial associates. For this study, 23 samples of the family Anthothelidae were collected from Norfolk (n = 12) and Baltimore Canyons (n = 11) from the western Atlantic in August 2012 and May 2013. Genetic testing found that these samples comprised two Anthothela species (Anthothela grandiflora and Anthothela sp.) and Alcyonium grandiflorum. DNA was extracted and sequenced with primers targeting the V4–V5 variable region of the 16S rRNA gene using 454 pyrosequencing with GS FLX Titanium chemistry. Results demonstrated that the coral host was the primary driver of bacterial community composition. Al. grandiflorum, dominated by Alteromonadales and Pirellulales had much higher species richness, and a distinct bacterial community compared to Anthothela samples. Anthothela species (A. grandiflora and Anthothela sp.) had very similar bacterial communities, dominated by Oceanospirillales and Spirochaetes. Additional analysis of core-conserved bacteria at 90% sample coverage revealed genus level conservation across Anthothela samples. This core included unclassified Oceanospirillales, Kiloniellales, Campylobacterales, and genus Spirochaeta. Members of this core were previously recognized for their functional capabilities in nitrogen cycling and suggest the possibility of a nearly complete nitrogen cycle within Anthothela species. Overall, many of the bacterial associates identified in this study have the potential to contribute to the acquisition and cycling of nutrients within the coral holobiont. PMID:27092120

  8. Bacterial endophyte communities of three agricultural important grass species differ in their response towards management regimes

    NASA Astrophysics Data System (ADS)

    Wemheuer, Franziska; Kaiser, Kristin; Karlovsky, Petr; Daniel, Rolf; Vidal, Stefan; Wemheuer, Bernd

    2017-01-01

    Endophytic bacteria are critical for plant growth and health. However, compositional and functional responses of bacterial endophyte communities towards agricultural practices are still poorly understood. Hence, we analyzed the influence of fertilizer application and mowing frequency on bacterial endophytes in three agriculturally important grass species. For this purpose, we examined bacterial endophytic communities in aerial plant parts of Dactylis glomerata L., Festuca rubra L., and Lolium perenne L. by pyrotag sequencing of bacterial 16S rRNA genes over two consecutive years. Although management regimes influenced endophyte communities, observed responses were grass species-specific. This might be attributed to several bacteria specifically associated with a single grass species. We further predicted functional profiles from obtained 16S rRNA data. These profiles revealed that predicted abundances of genes involved in plant growth promotion or nitrogen metabolism differed between grass species and between management regimes. Moreover, structural and functional community patterns showed no correlation to each other indicating that plant species-specific selection of endophytes is driven by functional rather than phylogenetic traits. The unique combination of 16S rRNA data and functional profiles provided a holistic picture of compositional and functional responses of bacterial endophytes in agricultural relevant grass species towards management practices.

  9. Waste Workers’ Exposure to Airborne Fungal and Bacterial Species in the Truck Cab and During Waste Collection

    PubMed Central

    Madsen, Anne Mette; Alwan, Taif; Ørberg, Anders; Uhrbrand, Katrine; Jørgensen, Marie Birk

    2016-01-01

    A large number of people work with garbage collection, and exposure to microorganisms is considered an occupational health problem. However, knowledge on microbial exposure at species level is limited. The aim of the study was to achieve knowledge on waste collectors’ exposure to airborne inhalable fungal and bacterial species during waste collection with focus on the transport of airborne microorganisms into the truck cab. Airborne microorganisms were collected with samplers mounted in the truck cab, on the workers’ clothes, and outdoors. Fungal and bacterial species were quantified and identified. The study showed that the workers were exposed to between 112 and 4.8×104 bacteria m−3 air and 326 and 4.6×104 fungi m−3 air. The personal exposures to bacteria and fungi were significantly higher than the concentrations measured in the truck cabs and in the outdoor references. On average, the fungal and bacterial concentrations in truck cabs were 111 and 7.7 times higher than outdoor reference measurements. In total, 23 fungal and 38 bacterial species were found and identified. Most fungal species belonged to the genus Penicillium and in total 11 Penicillium species were found. Identical fungal species were often found both in a personal sample and in the same person’s truck cab, but concentrations were on average 27 times higher in personal samples. Concentrations of fungal and bacterial species found only in the personal samples were lower than concentrations of species also found in truck cabs. Skin-related bacteria constituted a large fraction of bacterial isolates found in personal and truck cab samples. In total, six Staphylococcus species were found. In outdoor samples, no skin-related bacteria were found. On average, concentrations of bacterial species found both in the truck cab and personal samples were 77 times higher in personal samples than in truck cab samples. In conclusion, high concentrations of fungi were found in truck cabs, but the

  10. Temporal changes in species interactions in simple aquatic bacterial communities

    PubMed Central

    2012-01-01

    Background Organisms modify their environment and in doing so change the quantity and possibly the quality of available resources. Due to the two-way relationship between organisms and their resource environment, and the complexity it brings to biological communities, measuring species interactions reliably in any biological system is a challenging task. As the resource environment changes, the intensity and even the sign of interactions may vary in time. We used Serratia marcescens and Novosphingobium capsulatum bacteria to study how the interaction between resource environment and organisms influence the growth of the bacterial species during circa 200 generations. We used a sterile-filtering method to measure how changes in resource environment are reflected in growth rates of the two species. Results Changes in the resource environment caused complex time and species composition-dependent effects on bacterial growth performance. Variation in the quality of the growth medium indicated existence of temporally fluctuating within-species facilitation and inhibition, and between-species asymmetric facilitation. Conclusions The interactions between the community members could not be fully predicted based only on the knowledge of the growth performance of each member in isolation. Growth dynamics in sterile-filtered samples of the conditioned growth medium can reveal both biologically meaningful changes in resource availability and temporally changing facilitative resource-mediated interactions between study species. This is the first study we are aware of where the filter-sterilization – growth assay method is applied to study the effect of long-term changes in the environment on species interactions. PMID:22984961

  11. Dilemma of Dilemmas: How Collective and Individual Perspectives Can Clarify the Size Dilemma in Voluntary Linear Public Goods Dilemmas

    PubMed Central

    Shank, Daniel B.; Kashima, Yoshihisa; Saber, Saam; Gale, Thomas; Kirley, Michael

    2015-01-01

    Empirical findings on public goods dilemmas indicate an unresolved dilemma: that increasing size—the number of people in the dilemma—sometimes increases, decreases, or does not influence cooperation. We clarify this dilemma by first classifying public goods dilemma properties that specify individual outcomes as individual properties (e.g., Marginal Per Capita Return) and group outcomes as group properties (e.g., public good multiplier), mathematically showing how only one set of properties can remain constant as the dilemma size increases. Underpinning decision-making regarding individual and group properties, we propose that individuals are motivated by both individual and group preferences based on a theory of collective rationality. We use Van Lange's integrated model of social value orientations to operationalize these preferences as an amalgamation of outcomes for self, outcomes for others, and equality of outcomes. Based on this model, we then predict how the public good's benefit and size, combined with controlling individual versus group properties, produce different levels of cooperation in public goods dilemmas. A two (low vs. high benefit) by three (2-person baseline vs. 5-person holding constant individual properties vs. 5-person holding constant group properties) factorial experiment (group n = 99; participant n = 390) confirms our hypotheses. The results indicate that when holding constant group properties, size decreases cooperation. Yet when holding constant individual properties, size increases cooperation when benefit is low and does not affect cooperation when benefit is high. Using agent-based simulations of individual and group preferences vis-à-vis the integrative model, we fit a weighted simulation model to the empirical data. This fitted model is sufficient to reproduce the empirical results, but only when both individual (self-interest) and group (other-interest and equality) preference are included. Our research contributes to

  12. Positive and negative associations between bacterial species in dental root canals.

    PubMed

    Gomes, B P; Drucker, D B; Lilley, J D

    1994-01-01

    Significant associations have been previously reported between certain pairs of bacterial species isolated from human dental root canals. The aim of this study was to examine microbiologically a more extensive series of cases, with particular reference to obligate anaerobes which accounted for 64% of total isolations. A total of 65 different species was isolated and individual root canals yielded a maximum of eleven bacterial species. Highly significant positive associations (p < 0.001) were found between Peptostreptococcus spp. and Prevotella spp., between Peptostreptococcus spp. and P. melaninogenica, between P. micros and Prevotella spp., P. micros and P. melaninogenica and between Prevotella spp. and Eubacterium spp., all with an ODDS ratio of > 9.0. In contrast, negative and highly significant associations (p < 0.01) were found only between the four species pairs: B. vulgatus/F. necrophorum, P. magnus/Bifidobacterium spp., B. gracilis/F. nucleatum and between B. gracilis/Fusobacterium spp.; all with an ODDS ratio of < 0.5. Some previously published associations were confirmed and some new associations were found, while some negative associations became apparent.

  13. Validation of hierarchical cluster analysis for identification of bacterial species using 42 bacterial isolates

    NASA Astrophysics Data System (ADS)

    Ghebremedhin, Meron; Yesupriya, Shubha; Luka, Janos; Crane, Nicole J.

    2015-03-01

    Recent studies have demonstrated the potential advantages of the use of Raman spectroscopy in the biomedical field due to its rapidity and noninvasive nature. In this study, Raman spectroscopy is applied as a method for differentiating between bacteria isolates for Gram status and Genus species. We created models for identifying 28 bacterial isolates using spectra collected with a 785 nm laser excitation Raman spectroscopic system. In order to investigate the groupings of these samples, partial least squares discriminant analysis (PLSDA) and hierarchical cluster analysis (HCA) was implemented. In addition, cluster analyses of the isolates were performed using various data types consisting of, biochemical tests, gene sequence alignment, high resolution melt (HRM) analysis and antimicrobial susceptibility tests of minimum inhibitory concentration (MIC) and degree of antimicrobial resistance (SIR). In order to evaluate the ability of these models to correctly classify bacterial isolates using solely Raman spectroscopic data, a set of 14 validation samples were tested using the PLSDA models and consequently the HCA models. External cluster evaluation criteria of purity and Rand index were calculated at different taxonomic levels to compare the performance of clustering using Raman spectra as well as the other datasets. Results showed that Raman spectra performed comparably, and in some cases better than, the other data types with Rand index and purity values up to 0.933 and 0.947, respectively. This study clearly demonstrates that the discrimination of bacterial species using Raman spectroscopic data and hierarchical cluster analysis is possible and has the potential to be a powerful point-of-care tool in clinical settings.

  14. Host species shapes the co-occurrence patterns rather than diversity of stomach bacterial communities in pikas.

    PubMed

    Li, Huan; Li, Tongtong; Tu, Bo; Kou, Yongping; Li, Xiangzhen

    2017-07-01

    The mammalian stomach acts as an important barrier against ingested pathogens into the entire gastrointestinal tract, thereby playing a key role in host health. However, little is known regarding to the stomach microbial compositions in wild mammals and the factors that may influence the community compositions. Using high-throughput sequencing of the 16S rRNA gene, we characterized the stomach bacterial community compositions, diversity, and interactions in two common pika (Ochotona sp.) species in China, including Plateau pikas (Ochotona curzoniae) and Daurian pikas (Ochotona daurica) living in the Qinghai-Tibet Plateau and the Inner Mongolia Grassland, respectively. The bacterial communities can be divided into two distinct phylogenetic clusters. The most dominant bacteria in cluster I were unclassified bacteria. Cluster II was more diverse, predominantly consisting of Bacteroidetes, followed by unclassified bacteria, Firmicutes and Proteobacteria. Three dominant genera (Prevotella, Oscillospira, and Ruminococcus) in pika stomachs were significantly enriched in cluster II. In addition, seasons, host species, and sampling sites as well as body weight and sex had no significant impacts on the composition and diversity of pika stomach communities. Interestingly, Plateau pikas harbored a more complex bacterial network than Daurian pikas, and these two pika species showed different co-occurrence patterns. These results suggested that the pika stomach harbors a diverse but relatively stable and unique bacterial community, which is independent on host (host species, body weight, and sex) and measured environmental factors (sampling sites and seasons). Interestingly, host species shapes the microbial interactions rather than diversity of stomach bacterial communities in pikas, reflecting specific niche adaptation of stomach bacterial communities through species interactions.

  15. Massive Infection of Seabird Ticks with Bacterial Species Related to Coxiella burnetii

    PubMed Central

    Dietrich, Muriel; Lebarbenchon, Camille; Jaeger, Audrey; Le Rouzic, Céline; Bastien, Matthieu; Lagadec, Erwan; McCoy, Karen D.; Pascalis, Hervé; Le Corre, Matthieu; Dellagi, Koussay; Tortosa, Pablo

    2014-01-01

    Seabird ticks are known reservoirs of bacterial pathogens of medical importance; however, ticks parasitizing tropical seabirds have received less attention than their counterparts from temperate and subpolar regions. Recently, Rickettsia africae was described to infect seabird ticks of the western Indian Ocean and New Caledonia, constituting the only available data on bacterial pathogens associated with tropical seabird tick species. Here, we combined a pyrosequencing-based approach with a classical molecular analysis targeting bacteria of potential medical importance in order to describe the bacterial community in two tropical seabird ticks, Amblyomma loculosum and Carios (Ornithodoros) capensis. We also investigated the patterns of prevalence and host specificity within the biogeographical context of the western Indian Ocean islands. The bacterial community of the two tick species was characterized by a strong dominance of Coxiella and Rickettsia. Our data support a strict Coxiella-host tick specificity, a pattern resembling the one found for Rickettsia spp. in the same two seabird tick species. Both the high prevalence and stringent host tick specificity suggest that these bacteria may be tick symbionts with probable vertical transmission. Detailed studies of the pathogenicity of these bacteria will now be required to determine whether horizontal transmission can occur and to clarify their status as potential human pathogens. More generally, our results show that the combination of next generation sequencing with targeted detection/genotyping approaches proves to be efficient in poorly investigated fields where research can be considered to be starting from scratch. PMID:24657860

  16. Influences of Plant Species, Season and Location on Leaf Endophytic Bacterial Communities of Non-Cultivated Plants

    PubMed Central

    Ding, Tao; Melcher, Ulrich

    2016-01-01

    Bacteria are known to be associated endophytically with plants. Research on endophytic bacteria has identified their importance in food safety, agricultural production and phytoremediation. However, the diversity of endophytic bacterial communities and the forces that shape their compositions in non-cultivated plants are largely uncharacterized. In this study, we explored the diversity, community structure, and dynamics of endophytic bacteria in different plant species in the Tallgrass Prairie Preserve of northern Oklahoma, USA. High throughput sequencing of amplified segments of bacterial rDNA from 81 samples collected at four sampling times from five plant species at four locations identified 335 distinct OTUs at 97% sequence similarity, representing 16 phyla. Proteobacteria was the dominant phylum in the communities, followed by the phyla Bacteriodetes and Actinobacteria. Bacteria from four classes of Proteobacteria were detected with Alphaproteobacteria as the dominant class. Analysis of molecular variance revealed that host plant species and collecting date had significant influences on the compositions of the leaf endophytic bacterial communities. The proportion of Alphaproteobacteria was much higher in the communities from Asclepias viridis than from other plant species and differed from month to month. The most dominant bacterial groups identified in LDA Effect Size analysis showed host-specific patterns, indicating mutual selection between host plants and endophytic bacteria and that leaf endophytic bacterial compositions were dynamic, varying with the host plant’s growing season in three distinct patterns. In summary, next generation sequencing has revealed variations in the taxonomic compositions of leaf endophytic bacterial communities dependent primarily on the nature of the plant host species. PMID:26974817

  17. Influences of Plant Species, Season and Location on Leaf Endophytic Bacterial Communities of Non-Cultivated Plants.

    PubMed

    Ding, Tao; Melcher, Ulrich

    2016-01-01

    Bacteria are known to be associated endophytically with plants. Research on endophytic bacteria has identified their importance in food safety, agricultural production and phytoremediation. However, the diversity of endophytic bacterial communities and the forces that shape their compositions in non-cultivated plants are largely uncharacterized. In this study, we explored the diversity, community structure, and dynamics of endophytic bacteria in different plant species in the Tallgrass Prairie Preserve of northern Oklahoma, USA. High throughput sequencing of amplified segments of bacterial rDNA from 81 samples collected at four sampling times from five plant species at four locations identified 335 distinct OTUs at 97% sequence similarity, representing 16 phyla. Proteobacteria was the dominant phylum in the communities, followed by the phyla Bacteriodetes and Actinobacteria. Bacteria from four classes of Proteobacteria were detected with Alphaproteobacteria as the dominant class. Analysis of molecular variance revealed that host plant species and collecting date had significant influences on the compositions of the leaf endophytic bacterial communities. The proportion of Alphaproteobacteria was much higher in the communities from Asclepias viridis than from other plant species and differed from month to month. The most dominant bacterial groups identified in LDA Effect Size analysis showed host-specific patterns, indicating mutual selection between host plants and endophytic bacteria and that leaf endophytic bacterial compositions were dynamic, varying with the host plant's growing season in three distinct patterns. In summary, next generation sequencing has revealed variations in the taxonomic compositions of leaf endophytic bacterial communities dependent primarily on the nature of the plant host species.

  18. Catecholamines and in vitro growth of pathogenic bacteria: enhancement of growth varies greatly among bacterial species

    NASA Technical Reports Server (NTRS)

    Belay, Tesfaye; Aviles, Hernan; Vance, Monique; Fountain, Kimberly; Sonnenfeld, Gerald

    2003-01-01

    The purpose of this study was to examine the effects of catecholamines on in vitro growth of a range of bacterial species, including anaerobes. Bacteria tested included: Porphyromonas gingivalis, Bacteriodes fragilis, Shigella boydii, Shigella sonnie, Enterobacter Sp, and Salmonella choleraesuis. The results of the current study indicated that supplementation of bacterial cultures in minimal medium with norepinephrine or epinephrine did not result in increased growth of bacteria. Positive controls involving treatment of Escherichia coli with catecholamines did result in increased growth of that bacterial species. The results of the present study extend previous observations that showed differential capability of catecholamines to enhance bacterial growth in vitro.

  19. Bacterial communities associated with the pitcher fluids of three Nepenthes (Nepenthaceae) pitcher plant species growing in the wild.

    PubMed

    Chou, Lee Yiung; Clarke, Charles M; Dykes, Gary A

    2014-10-01

    Nepenthes pitcher plants produce modified jug-shaped leaves to attract, trap and digest insect prey. We used 16S rDNA cloning and sequencing to compare bacterial communities in pitcher fluids of each of three species, namely Nepenthes ampullaria, Nepenthes gracilis and Nepenthes mirabilis, growing in the wild. In contrast to previous greenhouse-based studies, we found that both opened and unopened pitchers harbored bacterial DNA. Pitchers of N. mirabilis had higher bacterial diversity as compared to other Nepenthes species. The composition of the bacterial communities could be different between pitcher types for N. mirabilis (ANOSIM: R = 0.340, p < 0.05). Other Nepenthes species had similar bacterial composition between pitcher types. SIMPER showed that more than 50 % of the bacterial taxa identified from the open pitchers of N. mirabilis were not found in other groups. Our study suggests that bacteria in N. mirabilis are divided into native and nonnative groups.

  20. Spatial and species variations in bacterial communities associated with corals from the Red Sea as revealed by pyrosequencing.

    PubMed

    Lee, On On; Yang, Jiangke; Bougouffa, Salim; Wang, Yong; Batang, Zenon; Tian, Renmao; Al-Suwailem, Abdulaziz; Qian, Pei-Yuan

    2012-10-01

    Microbial associations with corals are common and are most likely symbiotic, although their diversity and relationships with environmental factors and host species remain unclear. In this study, we adopted a 16S rRNA gene tag-pyrosequencing technique to investigate the bacterial communities associated with three stony Scleractinea and two soft Octocorallia corals from three locations in the Red Sea. Our results revealed highly diverse bacterial communities in the Red Sea corals, with more than 600 ribotypes detected and up to 1,000 species estimated from a single coral species. Altogether, 21 bacterial phyla were recovered from the corals, of which Gammaproteobacteria was the most dominant group, and Chloroflexi, Chlamydiae, and the candidate phylum WS3 were reported in corals for the first time. The associated bacterial communities varied greatly with location, where environmental conditions differed significantly. Corals from disturbed areas appeared to share more similar bacterial communities, but larger variations in community structures were observed between different coral species from pristine waters. Ordination methods identified salinity and depth as the most influential parameters affecting the abundance of Vibrio, Pseudoalteromonas, Serratia, Stenotrophomonas, Pseudomonas, and Achromobacter in the corals. On the other hand, bacteria such as Chloracidobacterium and Endozoicomonas were more sensitive to the coral species, suggesting that the host species type may be influential in the associated bacterial community, as well. The combined influences of the coral host and environmental factors on the associated microbial communities are discussed. This study represents the first comparative study using tag-pyrosequencing technology to investigate the bacterial communities in Red Sea corals.

  1. Spatial and Species Variations in Bacterial Communities Associated with Corals from the Red Sea as Revealed by Pyrosequencing

    PubMed Central

    Lee, On On; Yang, Jiangke; Bougouffa, Salim; Wang, Yong; Batang, Zenon; Tian, Renmao; Al-Suwailem, Abdulaziz

    2012-01-01

    Microbial associations with corals are common and are most likely symbiotic, although their diversity and relationships with environmental factors and host species remain unclear. In this study, we adopted a 16S rRNA gene tag-pyrosequencing technique to investigate the bacterial communities associated with three stony Scleractinea and two soft Octocorallia corals from three locations in the Red Sea. Our results revealed highly diverse bacterial communities in the Red Sea corals, with more than 600 ribotypes detected and up to 1,000 species estimated from a single coral species. Altogether, 21 bacterial phyla were recovered from the corals, of which Gammaproteobacteria was the most dominant group, and Chloroflexi, Chlamydiae, and the candidate phylum WS3 were reported in corals for the first time. The associated bacterial communities varied greatly with location, where environmental conditions differed significantly. Corals from disturbed areas appeared to share more similar bacterial communities, but larger variations in community structures were observed between different coral species from pristine waters. Ordination methods identified salinity and depth as the most influential parameters affecting the abundance of Vibrio, Pseudoalteromonas, Serratia, Stenotrophomonas, Pseudomonas, and Achromobacter in the corals. On the other hand, bacteria such as Chloracidobacterium and Endozoicomonas were more sensitive to the coral species, suggesting that the host species type may be influential in the associated bacterial community, as well. The combined influences of the coral host and environmental factors on the associated microbial communities are discussed. This study represents the first comparative study using tag-pyrosequencing technology to investigate the bacterial communities in Red Sea corals. PMID:22865078

  2. Impact of grassland management regimes on bacterial endophyte diversity differs with grass species.

    PubMed

    Wemheuer, F; Wemheuer, B; Kretzschmar, D; Pfeiffer, B; Herzog, S; Daniel, R; Vidal, S

    2016-04-01

    Most plant species are colonized by endophytic bacteria. Despite their importance for plant health and growth, the response of these bacteria to grassland management regimes is still not understood. Hence, we investigated the bacterial community structure in three agricultural important grass species Dactylis glomerata L., Festuca rubra L. and Lolium perenne L. with regard to fertilizer application and different mowing frequencies. For this purpose, above-ground plant material was collected from the Grassland Management Experiment (GrassMan) in Germany in September 2010 and 2011. DNA was extracted from surface-sterilized plant tissue and subjected to 16S rRNA gene PCRs. Endophytic community structures were assessed by denaturing gradient gel electrophoresis (DGGE)-based analysis of obtained PCR products. DGGE fingerprints revealed that fertilizer application significantly altered the endophytic communities in L. perenne and F. rubra but not in D. glomerata. Although no direct effect of mowing was observed, mowing frequencies in combination with fertilizer application had a significant impact on endophyte bacterial community structures. However, this effect was not observed for all three grass species in both years. Therefore, our results showed that management regimes changed the bacterial endophyte communities, but this effect was plant-specific and varied over time. Endophytic bacteria play an important role in plant health and growth. However, studies addressing the influence of grassland management regimes on these bacteria in above-ground plant parts are still missing. In this study, we present first evidence that fertilizer application significantly impacted bacterial community structures in three agricultural important grass species, whereas mowing had only a minor effect. Moreover, this effect was plant-specific and thus not visible for all grass species in each year. Consequently, this study sheds new light into the complex interaction of microbes and

  3. Studies on interaction of colloidal silver nanoparticles (SNPs) with five different bacterial species.

    PubMed

    Khan, S Sudheer; Mukherjee, Amitava; Chandrasekaran, N

    2011-10-01

    Silver nanoparticles (SNPs) are being increasingly used in many consumer products like textile fabrics, cosmetics, washing machines, food and drug products owing to its excellent antimicrobial properties. Here we have studied the adsorption and toxicity of SNPs on bacterial species such as Pseudomonas aeruginosa, Micrococcus luteus, Bacillus subtilis, Bacillus barbaricus and Klebsiella pneumoniae. The influence of zeta potential on the adsorption of SNPs on bacterial cell surface was investigated at acidic, neutral and alkaline pH and with varying salt (NaCl) concentrations (0.05, 0.1, 0.5, 1 and 1.5 M). The survival rate of bacterial species decreased with increase in adsorption of SNPs. Maximum adsorption and toxicity was observed at pH 5, and NaCl concentration of <0.5 M. A very less adsorption was observed at pH 9 and NaCl concentration >0.5 M, there by resulting in less toxicity. The zeta potential study suggests that, the adsorption of SNPs on the cell surface was related to electrostatic force of attraction. The equilibrium and kinetics of the adsorption process were also studied. The adsorption equilibrium isotherms fitted well to the Langmuir model. The kinetics of adsorption fitted best to pseudo-first-order. These findings form a basis for interpreting the interaction of nanoparticles with environmental bacterial species. Copyright © 2011 Elsevier B.V. All rights reserved.

  4. The Species Dilemma of Northeast Indian Mahseer (Actinopterygii: Cyprinidae): DNA Barcoding in Clarifying the Riddle

    PubMed Central

    Laskar, Boni A.; Bhattacharjee, Maloyjo J.; Dhar, Bishal; Mahadani, Pradosh; Kundu, Shantanu; Ghosh, Sankar K.

    2013-01-01

    Background The taxonomic validity of Northeast Indian endemic Mahseer species, Tor progeneius and Neolissochilus hexastichus, has been argued repeatedly. This is mainly due to disagreements in recognizing the species based on morphological characters. Consequently, both the species have been concealed for many decades. DNA barcoding has become a promising and an independent technique for accurate species level identification. Therefore, utilization of such technique in association with the traditional morphotaxonomic description can resolve the species dilemma of this important group of sport fishes. Methodology/Principal Findings Altogether, 28 mahseer specimens including paratypes were studied from different locations in Northeast India, and 24 morphometric characters were measured invariably. The Principal Component Analysis with morphometric data revealed five distinct groups of sample that were taxonomically categorized into 4 species, viz., Tor putitora, T. progeneius, Neolissochilus hexagonolepis and N. hexastichus. Analysis with a dataset of 76 DNA barcode sequences of different mahseer species exhibited that the queries of T. putitora and N. hexagonolepis clustered cohesively with the respective conspecific database sequences maintaining 0.8% maximum K2P divergence. The closest congeneric divergence was 3 times higher than the mean conspecific divergence and was considered as barcode gap. The maximum divergence among the samples of T. progeneius and T. putitora was 0.8% that was much below the barcode gap, indicating them being synonymous. The query sequences of N. hexastichus invariably formed a discrete and a congeneric clade with the database sequences and maintained the interspecific divergence that supported its distinct species status. Notably, N. hexastichus was encountered in a single site and seemed to be under threat. Conclusion This study substantiated the identification of N. hexastichus to be a true species, and tentatively regarded T

  5. Bacterial species colonizing the vagina of healthy women are not associated with race.

    PubMed

    Beamer, May A; Austin, Michele N; Avolia, Hilary A; Meyn, Leslie A; Bunge, Katherine E; Hillier, Sharon L

    2017-06-01

    The vaginal microbiota of 36 white versus 25 black asymptomatic women were compared using both cultivation-dependent and -independent identification. Significant differences by race were found in colonization and density of bacterial species. However, exclusion of 12 women with bacterial vaginosis by Nugent criteria resulted in no significant differences by race. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Phylogenetic analysis of bacterial and archaeal species in symptomatic and asymptomatic endodontic infections.

    PubMed

    Vickerman, M M; Brossard, K A; Funk, D B; Jesionowski, A M; Gill, S R

    2007-01-01

    Phylogenetic analysis of bacterial and archaeal 16S rRNA was used to examine polymicrobial communities within infected root canals of 20 symptomatic and 14 asymptomatic patients. Nucleotide sequences from approximately 750 clones amplified from each patient group with universal bacterial primers were matched to the Ribosomal Database Project II database. Phylotypes from 37 genera representing Actinobacteria, Bacteroidetes, Firmicutes, Fusobacteria and Proteobacteria were identified. Results were compared to those obtained with species-specific primers designed to detect Prevotella intermedia, Porphyromonas gingivalis, Porphyromonas endodontalis, Peptostreptococcus micros, Enterococcus sp., Streptococcus sp., Fusobacterium nucleatum, Tannerella forsythensis and Treponema denticola. Since members of the domain Archaea have been implicated in the severity of periodontal disease, and a recent report confirms that archaea are present in endodontic infections, 16S archaeal primers were also used to detect which patients carried these prokaryotes, to determine if their presence correlated with severity of the clinical symptoms. A Methanobrevibacter oralis-like species was detected in one asymptomatic and one symptomatic patient. DNA from root canals of these two patients was further analysed using species-specific primers to determine bacterial cohabitants. Trep. denticola was detected in the asymptomatic but not the symptomatic patient. Conversely, Porph. endodontalis was found in the symptomatic but not the asymptomatic patient. All other species except enterococci were detected with the species-specific primers in both patients. These results confirm the presence of archaea in root canals and provide additional insights into the polymicrobial communities in endodontic infections associated with clinical symptoms.

  7. Effect of species, breed, and age on bacterial load in bovine and bubaline semen

    PubMed Central

    Sannat, Chandrahas; Nair, Ajit; Sahu, S. B.; Sahasrabudhe, S. A.; Kumar, Ashish; Gupta, Amit Kumar; Shende, R. K.

    2015-01-01

    Aim: The present study was conducted to investigate the effect of species, breed and age on bacterial load in fresh and frozen semen of Cattle and Buffalo bull. Materials and Methods: Present study covered 56 cow and 10 buffalo bulls stationed at Central Semen Station Anjora, Durg (Chhattisgarh). Impact of breeds on bacterial load in semen was assessed using six breeds of cattle viz. Sahiwal, Gir, Red Sindhi, Tharparkar, Jersey and Holstein Friesian (HF) cross. Cow bulls were categorized into four different groups based on their age (<4 years, 4-5 years, 5-6 years and > 6 years) to study variation among age groups. Bacterial load was measured in fresh and frozen semen samples from these bulls using the standard plate count (SPC) method and count was expressed as colony forming unit (CFU) per ml of semen. Results: Higher bacterial load was reported in fresh (2.36 × 104 ± 1943 CFU/ml) and frozen (1.00 × 10 ± 90 CFU/ml) semen of cow bulls as compared to buffalo bulls (1.95 × 104 ± 2882 and 7.75 × 102 ± 160 CFU/ml in fresh and frozen semen, respectively). Jersey bull showed significantly higher bacterial count (p < 0.05) both in fresh (4.07 × 104 ± 13927 CFU/ml) and frozen (1.92 × 103 ± 178 CFU/ml) semen followed by HF cross, Sahiwal, Gir, Red Sindhi and Tharparkar bull. Bulls aged < 4 years and more than 6 years yielded increased bacterial load in their semen. Although a minor variation was reported between species and among age groups, no significant differences were measured. Conclusion: Bacterial load in semen did not differ significantly between species and age groups; however significant variation was reported among different breeds. Bulls of Jersey breed showed significantly higher bacterial load in semen as compared to the crossbred and indigenous bull. PMID:27047115

  8. Bacterial community composition associated with freshwater algae: species specificity vs. dependency on environmental conditions and source community.

    PubMed

    Eigemann, Falk; Hilt, Sabine; Salka, Ivette; Grossart, Hans-Peter

    2013-03-01

    We studied bacterial associations with the green alga Desmodesmus armatus and the diatom Stephanodiscus minutulus under changing environmental conditions and bacterial source communities, to evaluate whether bacteria-algae associations are species-specific or more generalized and determined by external factors. Axenic and xenic algae were incubated in situ with and without allelopathically active macrophytes, and in the laboratory with sterile and nonsterile lake water and an allelochemical, tannic acid (TA). Bacterial community composition (BCC) of algae-associated bacteria was analyzed by denaturing gradient gel electrophoresis (DGGE), nonmetric multidimensional scaling, cluster analyses, and sequencing of DGGE bands. BCC of xenic algal cultures of both species were not significantly affected by changes in their environment or bacterial source community, except in the case of TA additions. Species-specific interactions therefore appear to overrule the effects of environmental conditions and source communities. The BCC of xenic and axenic D. armatus cultures subjected to in situ bacterial colonization, however, had lower similarities (ca. 55%), indicating that bacterial precolonization is a strong factor for bacteria-algae associations irrespective of environmental conditions and source community. Our findings emphasize the ecological importance of species-specific bacteria-algae associations with important repercussions for other processes, such as the remineralization of nutrients, and organic matter dynamics. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  9. Life history correlates of fecal bacterial species richness in a wild population of the blue tit Cyanistes caeruleus

    PubMed Central

    Benskin, Clare McW H; Rhodes, Glenn; Pickup, Roger W; Mainwaring, Mark C; Wilson, Kenneth; Hartley, Ian R

    2015-01-01

    Very little is known about the normal gastrointestinal flora of wild birds, or how it might affect or reflect the host's life-history traits. The aim of this study was to survey the species richness of bacteria in the feces of a wild population of blue tits Cyanistes caeruleus and to explore the relationships between bacterial species richness and various life-history traits, such as age, sex, and reproductive success. Using PCR-TGGE, 55 operational taxonomic units (OTUs) were identified in blue tit feces. DNA sequencing revealed that the 16S rRNA gene was amplified from a diverse range of bacteria, including those that shared closest homology with Bacillus licheniformis, Campylobacter lari, Pseudomonas spp., and Salmonella spp. For adults, there was a significant negative relationship between bacterial species richness and the likelihood of being detected alive the following breeding season; bacterial richness was consistent across years but declined through the breeding season; and breeding pairs had significantly more similar bacterial richness than expected by chance alone. Reduced adult survival was correlated with the presence of an OTU most closely resembling C. lari; enhanced adult survival was associated with an OTU most similar to Arthrobacter spp. For nestlings, there was no significant change in bacterial species richness between the first and second week after hatching, and nestlings sharing the same nest had significantly more similar bacterial richness. Collectively, these results provide compelling evidence that bacterial species richness was associated with several aspects of the life history of their hosts. PMID:25750710

  10. Cuticles of European and American lobsters harbor diverse bacterial species and differ in disease susceptibility

    PubMed Central

    Whitten, Miranda M A; Davies, Charlotte E; Kim, Anita; Tlusty, Michael; Wootton, Emma C; Chistoserdov, Andrei; Rowley, Andrew F

    2014-01-01

    Diseases of lobster shells have a significant impact on fishing industries but the risk of disease transmission between different lobster species has yet to be properly investigated. This study compared bacterial biofilm communities from American (Homarus americanus) and European lobsters (H. gammarus), to assess both healthy cuticle and diseased cuticle during lesion formation. Culture-independent molecular techniques revealed diversity in the bacterial communities of cuticle biofilms both within and between the two lobster species, and identified three bacterial genera associated with shell lesions plus two putative beneficial bacterial species (detected exclusively in healthy cuticle or healing damaged cuticle). In an experimental aquarium shared between American and European lobsters, heterospecific transmission of potentially pathogenic bacteria appeared to be very limited; however, the claws of European lobsters were more likely to develop lesions when reared in the presence of American lobsters. Aquarium biofilms were also examined but revealed no candidate pathogens for environmental transmission. Aquimarina sp. ‘homaria’ (a potential pathogen associated with a severe epizootic form of shell disease) was detected at a much higher prevalence among American than European lobsters, but its presence correlated more with exacerbation of existing lesions rather than with lesion initiation. PMID:24817518

  11. Identification of different bacterial species in biofilms using confocal Raman microscopy

    NASA Astrophysics Data System (ADS)

    Beier, Brooke D.; Quivey, Robert G.; Berger, Andrew J.

    2010-11-01

    Confocal Raman microspectroscopy is used to discriminate between different species of bacteria grown in biofilms. Tests are performed using two bacterial species, Streptococcus sanguinis and Streptococcus mutans, which are major components of oral plaque and of particular interest due to their association with healthy and cariogenic plaque, respectively. Dehydrated biofilms of these species are studied as a simplified model of dental plaque. A prediction model based on principal component analysis and logistic regression is calibrated using pure biofilms of each species and validated on pure biofilms grown months later, achieving 96% accuracy in prospective classification. When biofilms of the two species are partially mixed together, Raman-based identifications are achieved within ~2 μm of the boundaries between species with 97% accuracy. This combination of spatial resolution and predication accuracy should be suitable for forming images of species distributions within intact two-species biofilms.

  12. Diversity and Phylogenetic Analyses of Bacterial Symbionts in Three Whitefly Species from Southeast Europe

    PubMed Central

    Skaljac, Marisa; Zanic, Katja; Puizina, Jasna; Lepen Pleic, Ivana; Ghanim, Murad

    2017-01-01

    Bemisia tabaci (Gennadius), Trialeurodes vaporariorum (Westwood), and Siphoninus phillyreae (Haliday) are whitefly species that harm agricultural crops in many regions of the world. These insects live in close association with bacterial symbionts that affect host fitness and adaptation to the environment. In the current study, we surveyed the infection of whitefly populations in Southeast Europe by various bacterial symbionts and performed phylogenetic analyses on the different symbionts detected. Arsenophonus and Hamiltonella were the most prevalent symbionts in all three whitefly species. Rickettsia was found to infect mainly B. tabaci, while Wolbachia mainly infected both B. tabaci and S. phillyreae. Furthermore, Cardinium was rarely found in the investigated whitefly populations, while Fritschea was never found in any of the whitefly species tested. Phylogenetic analyses revealed a diversity of several symbionts (e.g., Hamiltonella, Arsenophonus, Rickettsia), which appeared in several clades. Reproductively isolated B. tabaci and T. vaporariorum shared the same (or highly similar) Hamiltonella and Arsenophonus, while these symbionts were distinctive in S. phillyreae. Interestingly, Arsenophonus from S. phillyreae did not cluster with any of the reported sequences, which could indicate the presence of Arsenophonus, not previously associated with whiteflies. In this study, symbionts (Wolbachia, Rickettsia, and Cardinium) known to infect a wide range of insects each clustered in the same clades independently of the whitefly species. These results indicate horizontal transmission of bacterial symbionts between reproductively isolated whitefly species, a mechanism that can establish new infections that did not previously exist in whiteflies. PMID:29053633

  13. Diversity and Phylogenetic Analyses of Bacterial Symbionts in Three Whitefly Species from Southeast Europe.

    PubMed

    Skaljac, Marisa; Kanakala, Surapathrudu; Zanic, Katja; Puizina, Jasna; Pleic, Ivana Lepen; Ghanim, Murad

    2017-10-20

    Bemisia tabaci (Gennadius), Trialeurodes vaporariorum (Westwood), and Siphoninus phillyreae (Haliday) are whitefly species that harm agricultural crops in many regions of the world. These insects live in close association with bacterial symbionts that affect host fitness and adaptation to the environment. In the current study, we surveyed the infection of whitefly populations in Southeast Europe by various bacterial symbionts and performed phylogenetic analyses on the different symbionts detected. Arsenophonus and Hamiltonella were the most prevalent symbionts in all three whitefly species. Rickettsia was found to infect mainly B. tabaci, while Wolbachia mainly infected both B. tabaci and S. phillyreae. Furthermore, Cardinium was rarely found in the investigated whitefly populations, while Fritschea was never found in any of the whitefly species tested. Phylogenetic analyses revealed a diversity of several symbionts (e.g., Hamiltonella, Arsenophonus, Rickettsia), which appeared in several clades. Reproductively isolated B. tabaci and T. vaporariorum shared the same (or highly similar) Hamiltonella and Arsenophonus, while these symbionts were distinctive in S. phillyreae. Interestingly, Arsenophonus from S. phillyreae did not cluster with any of the reported sequences, which could indicate the presence of Arsenophonus, not previously associated with whiteflies. In this study, symbionts (Wolbachia, Rickettsia, and Cardinium) known to infect a wide range of insects each clustered in the same clades independently of the whitefly species. These results indicate horizontal transmission of bacterial symbionts between reproductively isolated whitefly species, a mechanism that can establish new infections that did not previously exist in whiteflies.

  14. Cuticles of European and American lobsters harbor diverse bacterial species and differ in disease susceptibility.

    PubMed

    Whitten, Miranda M A; Davies, Charlotte E; Kim, Anita; Tlusty, Michael; Wootton, Emma C; Chistoserdov, Andrei; Rowley, Andrew F

    2014-06-01

    Diseases of lobster shells have a significant impact on fishing industries but the risk of disease transmission between different lobster species has yet to be properly investigated. This study compared bacterial biofilm communities from American (Homarus americanus) and European lobsters (H. gammarus), to assess both healthy cuticle and diseased cuticle during lesion formation. Culture-independent molecular techniques revealed diversity in the bacterial communities of cuticle biofilms both within and between the two lobster species, and identified three bacterial genera associated with shell lesions plus two putative beneficial bacterial species (detected exclusively in healthy cuticle or healing damaged cuticle). In an experimental aquarium shared between American and European lobsters, heterospecific transmission of potentially pathogenic bacteria appeared to be very limited; however, the claws of European lobsters were more likely to develop lesions when reared in the presence of American lobsters. Aquarium biofilms were also examined but revealed no candidate pathogens for environmental transmission. Aquimarina sp. 'homaria' (a potential pathogen associated with a severe epizootic form of shell disease) was detected at a much higher prevalence among American than European lobsters, but its presence correlated more with exacerbation of existing lesions rather than with lesion initiation. © 2014 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

  15. Root and Rhizosphere Bacterial Phosphatase Activity Varies with Tree Species and Soil Phosphorus Availability in Puerto Rico Tropical Forest

    PubMed Central

    Cabugao, Kristine G.; Timm, Collin M.; Carrell, Alyssa A.; Childs, Joanne; Lu, Tse-Yuan S.; Pelletier, Dale A.; Weston, David J.; Norby, Richard J.

    2017-01-01

    Tropical forests generally occur on highly weathered soils that, in combination with the immobility of phosphorus (P), often result in soils lacking orthophosphate, the form of P most easily metabolized by plants and microbes. In these soils, mineralization of organic P can be the major source for orthophosphate. Both plants and microbes encode for phosphatases capable of mineralizing a range of organic P compounds. However, the activity of these enzymes depends on several edaphic factors including P availability, tree species, and microbial communities. Thus, phosphatase activity in both roots and the root microbial community constitute an important role in P mineralization and P nutrient dynamics that are not well studied in tropical forests. To relate phosphatase activity of roots and bacteria in tropical forests, we measured phosphatase activity in roots and bacterial isolates as well as bacterial community composition from the rhizosphere. Three forests in the Luquillo Mountains of Puerto Rico were selected to represent a range of soil P availability as measured using the resin P method. Within each site, a minimum of three tree species were chosen to sample. Root and bacterial phosphatase activity were both measured using a colorimetric assay with para-nitrophenyl phosphate as a substrate for the phosphomonoesterase enzyme. Both root and bacterial phosphatase were chiefly influenced by tree species. Though tree species was the only significant factor in root phosphatase activity, there was a negative trend between soil P availability and phosphatase activity in linear regressions of average root phosphatase and resin P. Permutational multivariate analysis of variance of bacterial community composition based on 16S amplicon sequencing indicated that bacterial composition was strongly controlled by soil P availability (p-value < 0.05). These results indicate that although root and bacterial phosphatase activity were influenced by tree species; bacterial

  16. Root and Rhizosphere Bacterial Phosphatase Activity Varies with Tree Species and Soil Phosphorus Availability in Puerto Rico Tropical Forest.

    PubMed

    Cabugao, Kristine G; Timm, Collin M; Carrell, Alyssa A; Childs, Joanne; Lu, Tse-Yuan S; Pelletier, Dale A; Weston, David J; Norby, Richard J

    2017-01-01

    Tropical forests generally occur on highly weathered soils that, in combination with the immobility of phosphorus (P), often result in soils lacking orthophosphate, the form of P most easily metabolized by plants and microbes. In these soils, mineralization of organic P can be the major source for orthophosphate. Both plants and microbes encode for phosphatases capable of mineralizing a range of organic P compounds. However, the activity of these enzymes depends on several edaphic factors including P availability, tree species, and microbial communities. Thus, phosphatase activity in both roots and the root microbial community constitute an important role in P mineralization and P nutrient dynamics that are not well studied in tropical forests. To relate phosphatase activity of roots and bacteria in tropical forests, we measured phosphatase activity in roots and bacterial isolates as well as bacterial community composition from the rhizosphere. Three forests in the Luquillo Mountains of Puerto Rico were selected to represent a range of soil P availability as measured using the resin P method. Within each site, a minimum of three tree species were chosen to sample. Root and bacterial phosphatase activity were both measured using a colorimetric assay with para-nitrophenyl phosphate as a substrate for the phosphomonoesterase enzyme. Both root and bacterial phosphatase were chiefly influenced by tree species. Though tree species was the only significant factor in root phosphatase activity, there was a negative trend between soil P availability and phosphatase activity in linear regressions of average root phosphatase and resin P. Permutational multivariate analysis of variance of bacterial community composition based on 16S amplicon sequencing indicated that bacterial composition was strongly controlled by soil P availability ( p -value < 0.05). These results indicate that although root and bacterial phosphatase activity were influenced by tree species; bacterial

  17. Intra- and inter-species interactions within biofilms of important foodborne bacterial pathogens

    PubMed Central

    Giaouris, Efstathios; Heir, Even; Desvaux, Mickaël; Hébraud, Michel; Møretrø, Trond; Langsrud, Solveig; Doulgeraki, Agapi; Nychas, George-John; Kačániová, Miroslava; Czaczyk, Katarzyna; Ölmez, Hülya; Simões, Manuel

    2015-01-01

    A community-based sessile life style is the normal mode of growth and survival for many bacterial species. Under such conditions, cell-to-cell interactions are inevitable and ultimately lead to the establishment of dense, complex and highly structured biofilm populations encapsulated in a self-produced extracellular matrix and capable of coordinated and collective behavior. Remarkably, in food processing environments, a variety of different bacteria may attach to surfaces, survive, grow, and form biofilms. Salmonella enterica, Listeria monocytogenes, Escherichia coli, and Staphylococcus aureus are important bacterial pathogens commonly implicated in outbreaks of foodborne diseases, while all are known to be able to create biofilms on both abiotic and biotic surfaces. Particularly challenging is the attempt to understand the complexity of inter-bacterial interactions that can be encountered in such unwanted consortia, such as competitive and cooperative ones, together with their impact on the final outcome of these communities (e.g., maturation, physiology, antimicrobial resistance, virulence, dispersal). In this review, up-to-date data on both the intra- and inter-species interactions encountered in biofilms of these pathogens are presented. A better understanding of these interactions, both at molecular and biophysical levels, could lead to novel intervention strategies for controlling pathogenic biofilm formation in food processing environments and thus improve food safety. PMID:26347727

  18. Bacterial and fungal endophthalmitis in upper Egypt: related species and risk factors.

    PubMed

    Gharamah, A A; Moharram, A M; Ismail, M A; Al-Hussaini, A K

    2012-08-01

    To study risk factors, contributing factors of bacterial and fungal endophthalmitis in Upper Egypt, test the isolated species sensitive to some therapeutic agents, and to investigate the air-borne bacteria and fungi in opthalmology operating rooms. Thirty one cases of endophthalmitis were clinically diagnosed and microbiologically studied. Indoor air-borne bacteria and fungi inside four air-conditioned operating rooms in the Ophthalmology Department at Assiut University Hospitals were also investigated. The isolated microbes from endophthalmitis cases were tested for their ability to produce some extracellular enzymes including protease, lipase, urease, phosphatase and catalase. Also the ability of 5 fungal isolates from endophthalmitis origin to produce mycotoxins and their sensitivity to some therapeutic agents were studied. Results showed that bacteria and fungi were responsihle for infection in 10 and 6 cases of endophthalmitis, respectively and only 2 cases produced a mixture of bacteria and fungi. Trauma was the most prevalent risk factor of endophthalmitis where 58.1% of the 31 cases were due to trauma. In ophthalmology operating rooms, different bacterial and fungal species were isolated. 8 bacterial and 5 fungal isolates showed their ability to produce enzymes while only 3 fungal isolates were able to produce mycotoxins. Terbinafine showed the highest effect against most isolates in vitro. The ability of bacterial and fungal isolates to produce extracellular enzymes and mycotoxins may be aid in the invasion and destruction of eye tissues. Microbial contamination of operating rooms with air-borne bacteria and fungi in the present work may be a source of postoperative endophthalmitis.

  19. Novel Perspectives on the Characterization of Species-Dependent Optical Signatures of Bacterial Colonies by Digital Holography.

    PubMed

    Buzalewicz, Igor; Kujawińska, Małgorzata; Krauze, Wojciech; Podbielska, Halina

    2016-01-01

    The use of light diffraction for the microbiological diagnosis of bacterial colonies was a significant breakthrough with widespread implications for the food industry and clinical practice. We previously confirmed that optical sensors for bacterial colony light diffraction can be used for bacterial identification. This paper is focused on the novel perspectives of this method based on digital in-line holography (DIH), which is able to reconstruct the amplitude and phase properties of examined objects, as well as the amplitude and phase patterns of the optical field scattered/diffracted by the bacterial colony in any chosen observation plane behind the object from single digital hologram. Analysis of the amplitude and phase patterns inside a colony revealed its unique optical properties, which are associated with the internal structure and geometry of the bacterial colony. Moreover, on a computational level, it is possible to select the desired scattered/diffracted pattern within the entire observation volume that exhibits the largest amount of unique, differentiating bacterial features. These properties distinguish this method from the already proposed sensing techniques based on light diffraction/scattering of bacterial colonies. The reconstructed diffraction patterns have a similar spatial distribution as the recorded Fresnel patterns, previously applied for bacterial identification with over 98% accuracy, but they are characterized by both intensity and phase distributions. Our results using digital holography provide new optical discriminators of bacterial species revealed in one single step in form of new optical signatures of bacterial colonies: digital holograms, reconstructed amplitude and phase patterns, as well as diffraction patterns from all observation space, which exhibit species-dependent features. To the best of our knowledge, this is the first report on bacterial colony analysis via digital holography and our study represents an innovative approach

  20. Novel Perspectives on the Characterization of Species-Dependent Optical Signatures of Bacterial Colonies by Digital Holography

    PubMed Central

    Buzalewicz, Igor; Kujawińska, Małgorzata; Krauze, Wojciech; Podbielska, Halina

    2016-01-01

    The use of light diffraction for the microbiological diagnosis of bacterial colonies was a significant breakthrough with widespread implications for the food industry and clinical practice. We previously confirmed that optical sensors for bacterial colony light diffraction can be used for bacterial identification. This paper is focused on the novel perspectives of this method based on digital in-line holography (DIH), which is able to reconstruct the amplitude and phase properties of examined objects, as well as the amplitude and phase patterns of the optical field scattered/diffracted by the bacterial colony in any chosen observation plane behind the object from single digital hologram. Analysis of the amplitude and phase patterns inside a colony revealed its unique optical properties, which are associated with the internal structure and geometry of the bacterial colony. Moreover, on a computational level, it is possible to select the desired scattered/diffracted pattern within the entire observation volume that exhibits the largest amount of unique, differentiating bacterial features. These properties distinguish this method from the already proposed sensing techniques based on light diffraction/scattering of bacterial colonies. The reconstructed diffraction patterns have a similar spatial distribution as the recorded Fresnel patterns, previously applied for bacterial identification with over 98% accuracy, but they are characterized by both intensity and phase distributions. Our results using digital holography provide new optical discriminators of bacterial species revealed in one single step in form of new optical signatures of bacterial colonies: digital holograms, reconstructed amplitude and phase patterns, as well as diffraction patterns from all observation space, which exhibit species-dependent features. To the best of our knowledge, this is the first report on bacterial colony analysis via digital holography and our study represents an innovative approach

  1. Dissolution and degradation of crude oil droplets by different bacterial species and consortia by microcosm microfluidics

    NASA Astrophysics Data System (ADS)

    Jalali, Maryam; Sheng, Jian

    2017-11-01

    Bacteria are involved in cleanup and degradation of crude oil in polluted marine and soil environments. A number of bacterial species have been identified for consuming petroleum hydrocarbons with diverse metabolic capabilities. We conducted laboratory experiments to investigate bacterial consumption by monitoring the volume change to oil droplets as well as effects of oil droplet size on this process. To conduct our study, we developed a micro-bioassay containing an enclosed chamber with bottom substrate printed with stationary oil microdroplets and a digital holographic interferometer (DHI). The morphology of microdroplets was monitored in real time over 100 hours and instantaneous flow field was also measured by digital holographic microscope. The substrates with printed oil droplets were further evaluated with atomic force microscopy (AFM) at the end of each experiment. Three different bacteria species, Pseudomonas sp, Alcanivorax borkumensis, and Marinobacter hydrocarbonoclasticus, as well as six bacterial consortia were used in this study. The results show that droplets smaller than 20µm in diameter are not subject to bacterial degradation and the volume of droplet did not change beyond dissolution. Substantial species-specific behaviors have been observed in isolates. The experiments of consortia and various flow shears on biodegradation and dissolution are ongoing and will be reported.

  2. Assessing the viability of bacterial species in drinking water by combined cellular and molecular analyses.

    PubMed

    Kahlisch, Leila; Henne, Karsten; Gröbe, Lothar; Brettar, Ingrid; Höfle, Manfred G

    2012-02-01

    The question which bacterial species are present in water and if they are viable is essential for drinking water safety but also of general relevance in aquatic ecology. To approach this question we combined propidium iodide/SYTO9 staining ("live/dead staining" indicating membrane integrity), fluorescence-activated cell sorting (FACS) and community fingerprinting for the analysis of a set of tap water samples. Live/dead staining revealed that about half of the bacteria in the tap water had intact membranes. Molecular analysis using 16S rRNA and 16S rRNA gene-based single-strand conformation polymorphism (SSCP) fingerprints and sequencing of drinking water bacteria before and after FACS sorting revealed: (1) the DNA- and RNA-based overall community structure differed substantially, (2) the community retrieved from RNA and DNA reflected different bacterial species, classified as 53 phylotypes (with only two common phylotypes), (3) the percentage of phylotypes with intact membranes or damaged cells were comparable for RNA- and DNA-based analyses, and (4) the retrieved species were primarily of aquatic origin. The pronounced difference between phylotypes obtained from DNA extracts (dominated by Betaproteobacteria, Bacteroidetes, and Actinobacteria) and from RNA extracts (dominated by Alpha-, Beta-, Gammaproteobacteria, Bacteroidetes, and Cyanobacteria) demonstrate the relevance of concomitant RNA and DNA analyses for drinking water studies. Unexpected was that a comparable fraction (about 21%) of phylotypes with membrane-injured cells was observed for DNA- and RNA-based analyses, contradicting the current understanding that RNA-based analyses represent the actively growing fraction of the bacterial community. Overall, we think that this combined approach provides an interesting tool for a concomitant phylogenetic and viability analysis of bacterial species of drinking water.

  3. Host species and developmental stage, but not host social structure, affects bacterial community structure in socially polymorphic bees.

    PubMed

    McFrederick, Quinn S; Wcislo, William T; Hout, Michael C; Mueller, Ulrich G

    2014-05-01

    Social transmission and host developmental stage are thought to profoundly affect the structure of bacterial communities associated with honey bees and bumble bees, but these ideas have not been explored in other bee species. The halictid bees Megalopta centralis and M. genalis exhibit intrapopulation social polymorphism, which we exploit to test whether bacterial communities differ by host social structure, developmental stage, or host species. We collected social and solitary Megalopta nests and sampled bees and nest contents from all stages of host development. To survey these bacterial communities, we used 16S rRNA gene 454 pyrosequencing. We found no effect of social structure, but found differences by host species and developmental stage. Wolbachia prevalence differed between the two host species. Bacterial communities associated with different developmental stages appeared to be driven by environmentally acquired bacteria. A Lactobacillus kunkeei clade bacterium that is consistently associated with other bee species was dominant in pollen provisions and larval samples, but less abundant in mature larvae and pupae. Foraging adults appeared to often reacquire L. kunkeei clade bacteria, likely while foraging at flowers. Environmental transmission appears to be more important than social transmission for Megalopta bees at the cusp between social and solitary behavior. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  4. Studies on Batch Production of Bacterial Concentrates from Mixed Species Lactic Starters

    PubMed Central

    Pettersson, H. E.

    1975-01-01

    Optimum growth conditions for mixed species starter FDs 0172 at constant pH in skim milk, whey, and tryptone medium were investigated. Growth rate and maximum population were optimal at 30 C. pH values between 5.5 and 7.0 did not influence the growth rate and maximum population obtainable. Lactic acid-producing activity declined rapidly after reaching the end of the exponential growth phase. The bacterial balance was found to be influenced by the growth parameters: media, pH, temperature, and neutralizer. Skim milk or whey medium at 25 C, pH 6.5, and neutralized with 20% (vol/vol) NH4OH kept the bacterial balance almost constant throughout the cultivation. Grown in tryptone medium at constant pH, the changes in bacterial balance and other metabolic activities were striking compared to the other two media tested. The effect of lactate as an inhibitor was found to be complex, changing with the growth conditions. Concentrates made from mixed species starters FDs 0172, FD 0570, CH 0170, CHs 0170, and T 27 were comparable to controls when cultivated at the optimum conditions found and thereafter centrifuged. Aroma production, proteolytic activity, and CO2 production did not change significantly compared to controls when cultivated at optimum conditions in skim milk or whey medium. PMID:16350009

  5. Zero-knowledge cooperation in dilemma games.

    PubMed

    Huck, Steffen; Normann, Hans Theo; Oechssler, Jorg

    2003-01-07

    We consider a very simple adaptive rule that induces cooperative behavior in a large class of dilemma games. The rule has a Pavlovian flavor and can be described as win-continue, lose-reverse. It assumes no knowledge about the underlying structure of the environment (the "rules of the game") and requires very little cognitive effort. Both features make it an appealing candidate for explaining the emergence of cooperative behavior in non-human species. Copyright 2003 Elsevier Science Ltd.

  6. Microplastics as a vector for the transport of the bacterial fish pathogen species Aeromonas salmonicida.

    PubMed

    Viršek, Manca Kovač; Lovšin, Marija Nika; Koren, Špela; Kržan, Andrej; Peterlin, Monika

    2017-12-15

    Microplastics is widespread in the marine environment where it can cause numerous negative effects. It can provide space for the growth of organisms and serves as a vector for the long distance transfer of marine microorganisms. In this study, we examined the sea surface concentrations of microplastics in the North Adriatic and characterized bacterial communities living on the microplastics. DNA from microplastics particles was isolated by three different methods, followed by PCR amplification of 16S rDNA, clone libraries preparation and phylogenetic analysis. 28 bacterial species were identified on the microplastics particles including Aeromonas spp. and hydrocarbon-degrading bacterial species. Based on the 16S rDNA sequences the pathogenic fish bacteria Aeromonas salmonicida was identified for the first time on microplastics. Because A. salmonicida is responsible for illnesses in fish, it is crucial to get answers if and how microplastics pollution is responsible for spreading of diseases. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. What Makes a Bacterial Species Pathogenic?:Comparative Genomic Analysis of the Genus Leptospira

    PubMed Central

    Fouts, Derrick E.; Matthias, Michael A.; Adhikarla, Haritha; Adler, Ben; Amorim-Santos, Luciane; Berg, Douglas E.; Bulach, Dieter; Buschiazzo, Alejandro; Chang, Yung-Fu; Galloway, Renee L.; Haake, David A.; Haft, Daniel H.; Hartskeerl, Rudy; Ko, Albert I.; Levett, Paul N.; Matsunaga, James; Mechaly, Ariel E.; Monk, Jonathan M.; Nascimento, Ana L. T.; Nelson, Karen E.; Palsson, Bernhard; Peacock, Sharon J.; Picardeau, Mathieu; Ricaldi, Jessica N.; Thaipandungpanit, Janjira; Wunder, Elsio A.; Yang, X. Frank; Zhang, Jun-Jie; Vinetz, Joseph M.

    2016-01-01

    Leptospirosis, caused by spirochetes of the genus Leptospira, is a globally widespread, neglected and emerging zoonotic disease. While whole genome analysis of individual pathogenic, intermediately pathogenic and saprophytic Leptospira species has been reported, comprehensive cross-species genomic comparison of all known species of infectious and non-infectious Leptospira, with the goal of identifying genes related to pathogenesis and mammalian host adaptation, remains a key gap in the field. Infectious Leptospira, comprised of pathogenic and intermediately pathogenic Leptospira, evolutionarily diverged from non-infectious, saprophytic Leptospira, as demonstrated by the following computational biology analyses: 1) the definitive taxonomy and evolutionary relatedness among all known Leptospira species; 2) genomically-predicted metabolic reconstructions that indicate novel adaptation of infectious Leptospira to mammals, including sialic acid biosynthesis, pathogen-specific porphyrin metabolism and the first-time demonstration of cobalamin (B12) autotrophy as a bacterial virulence factor; 3) CRISPR/Cas systems demonstrated only to be present in pathogenic Leptospira, suggesting a potential mechanism for this clade’s refractoriness to gene targeting; 4) finding Leptospira pathogen-specific specialized protein secretion systems; 5) novel virulence-related genes/gene families such as the Virulence Modifying (VM) (PF07598 paralogs) proteins and pathogen-specific adhesins; 6) discovery of novel, pathogen-specific protein modification and secretion mechanisms including unique lipoprotein signal peptide motifs, Sec-independent twin arginine protein secretion motifs, and the absence of certain canonical signal recognition particle proteins from all Leptospira; and 7) and demonstration of infectious Leptospira-specific signal-responsive gene expression, motility and chemotaxis systems. By identifying large scale changes in infectious (pathogenic and intermediately pathogenic

  8. What Makes a Bacterial Species Pathogenic?:Comparative Genomic Analysis of the Genus Leptospira.

    PubMed

    Fouts, Derrick E; Matthias, Michael A; Adhikarla, Haritha; Adler, Ben; Amorim-Santos, Luciane; Berg, Douglas E; Bulach, Dieter; Buschiazzo, Alejandro; Chang, Yung-Fu; Galloway, Renee L; Haake, David A; Haft, Daniel H; Hartskeerl, Rudy; Ko, Albert I; Levett, Paul N; Matsunaga, James; Mechaly, Ariel E; Monk, Jonathan M; Nascimento, Ana L T; Nelson, Karen E; Palsson, Bernhard; Peacock, Sharon J; Picardeau, Mathieu; Ricaldi, Jessica N; Thaipandungpanit, Janjira; Wunder, Elsio A; Yang, X Frank; Zhang, Jun-Jie; Vinetz, Joseph M

    2016-02-01

    Leptospirosis, caused by spirochetes of the genus Leptospira, is a globally widespread, neglected and emerging zoonotic disease. While whole genome analysis of individual pathogenic, intermediately pathogenic and saprophytic Leptospira species has been reported, comprehensive cross-species genomic comparison of all known species of infectious and non-infectious Leptospira, with the goal of identifying genes related to pathogenesis and mammalian host adaptation, remains a key gap in the field. Infectious Leptospira, comprised of pathogenic and intermediately pathogenic Leptospira, evolutionarily diverged from non-infectious, saprophytic Leptospira, as demonstrated by the following computational biology analyses: 1) the definitive taxonomy and evolutionary relatedness among all known Leptospira species; 2) genomically-predicted metabolic reconstructions that indicate novel adaptation of infectious Leptospira to mammals, including sialic acid biosynthesis, pathogen-specific porphyrin metabolism and the first-time demonstration of cobalamin (B12) autotrophy as a bacterial virulence factor; 3) CRISPR/Cas systems demonstrated only to be present in pathogenic Leptospira, suggesting a potential mechanism for this clade's refractoriness to gene targeting; 4) finding Leptospira pathogen-specific specialized protein secretion systems; 5) novel virulence-related genes/gene families such as the Virulence Modifying (VM) (PF07598 paralogs) proteins and pathogen-specific adhesins; 6) discovery of novel, pathogen-specific protein modification and secretion mechanisms including unique lipoprotein signal peptide motifs, Sec-independent twin arginine protein secretion motifs, and the absence of certain canonical signal recognition particle proteins from all Leptospira; and 7) and demonstration of infectious Leptospira-specific signal-responsive gene expression, motility and chemotaxis systems. By identifying large scale changes in infectious (pathogenic and intermediately pathogenic

  9. Moral Dilemmas of Young Adults.

    ERIC Educational Resources Information Center

    Rest, James R.

    This study describes moral dilemmas that young adults (ages 18-24) formulate spontaneously and examines the relationship between these dilemmas and the subjects' environment and scores on a standardized test. Fifty-two subjects were tested both in 1976 and 1978, creating 104 subject-oriented dilemmas. Thirty-two were in college, 17 were not, and…

  10. Bacterial diversity of bacteriomes and organs of reproductive, digestive and excretory systems in two cicada species (Hemiptera: Cicadidae)

    PubMed Central

    Zheng, Zhou; Wang, Dandan; He, Hong

    2017-01-01

    Cicadas form intimate symbioses with bacteria to obtain nutrients that are scarce in the xylem fluid they feed on. The obligate symbionts in cicadas are purportedly confined to specialized bacteriomes, but knowledge of bacterial communities associated with cicadas is limited. Bacterial communities in the bacteriomes and organs of reproductive, digestive and excretory systems of two cicada species (Platypleura kaempferi and Meimuna mongolica) were investigated using different methods, and the bacterial diversity and distribution patterns of dominant bacteria in different tissues were compared. Within each species, the bacterial communities of testes are significantly different from those of bacteriomes and ovaries. The dominant endosymbiont Candidatus Sulcia muelleri is found not only in the bacteriomes and reproductive organs, but also in the “filter chamber + conical segment” of both species. The transmission mode of this endosymbiont in the alimentary canal and its effect on physiological processes merits further study. A novel bacterium of Rhizobiales, showing ~80% similarity to Candidatus Hodgkinia cicadicola, is dominant in the bacteriomes and ovaries of P. kaempferi. Given that the genome of H. cicadicola exhibits rapid sequence evolution, it is possible that this novel bacterium is a related endosymbiont with beneficial trophic functions similar to that of H. cicadicola in some other cicadas. Failure to detect H. cicadicola in M. mongolica suggests that it has been subsequently replaced by another bacterium, a yeast or gut microbiota which compensates for the loss of H. cicadicola. The distribution of this novel Rhizobiales species in other cicadas and its identification require further investigation to help establish the definition of the bacterial genus Candidatus Hodgkinia and to provide more information on sequence divergence of related endosymbionts of cicadas. Our results highlight the complex bacterial communities of cicadas, and are informative

  11. Bacterial diversity of bacteriomes and organs of reproductive, digestive and excretory systems in two cicada species (Hemiptera: Cicadidae).

    PubMed

    Zheng, Zhou; Wang, Dandan; He, Hong; Wei, Cong

    2017-01-01

    Cicadas form intimate symbioses with bacteria to obtain nutrients that are scarce in the xylem fluid they feed on. The obligate symbionts in cicadas are purportedly confined to specialized bacteriomes, but knowledge of bacterial communities associated with cicadas is limited. Bacterial communities in the bacteriomes and organs of reproductive, digestive and excretory systems of two cicada species (Platypleura kaempferi and Meimuna mongolica) were investigated using different methods, and the bacterial diversity and distribution patterns of dominant bacteria in different tissues were compared. Within each species, the bacterial communities of testes are significantly different from those of bacteriomes and ovaries. The dominant endosymbiont Candidatus Sulcia muelleri is found not only in the bacteriomes and reproductive organs, but also in the "filter chamber + conical segment" of both species. The transmission mode of this endosymbiont in the alimentary canal and its effect on physiological processes merits further study. A novel bacterium of Rhizobiales, showing ~80% similarity to Candidatus Hodgkinia cicadicola, is dominant in the bacteriomes and ovaries of P. kaempferi. Given that the genome of H. cicadicola exhibits rapid sequence evolution, it is possible that this novel bacterium is a related endosymbiont with beneficial trophic functions similar to that of H. cicadicola in some other cicadas. Failure to detect H. cicadicola in M. mongolica suggests that it has been subsequently replaced by another bacterium, a yeast or gut microbiota which compensates for the loss of H. cicadicola. The distribution of this novel Rhizobiales species in other cicadas and its identification require further investigation to help establish the definition of the bacterial genus Candidatus Hodgkinia and to provide more information on sequence divergence of related endosymbionts of cicadas. Our results highlight the complex bacterial communities of cicadas, and are informative for

  12. Combinations of bacterial species associated with symptomatic endodontic infections in a Chinese population.

    PubMed

    Qi, Z; Cao, H; Jiang, H; Zhao, J; Tang, Z

    2016-01-01

    To use microarrays to detect 11 selected bacteria in infected root canals, revealing bacterial combinations that are associated with clinical symptoms and signs of primary endodontic infections in a Chinese population. DNA was extracted from 90 samples collected from the root canals of teeth with primary endodontic infections in a Chinese population, and the 16S rRNA gene was amplified by polymerase chain reaction (PCR). The PCR products were hybridized to microarrays containing specific oligonucleotide probes targeting 11 species, and the arrays were screened with a confocal laser scanner. Pearson's chi-squared test and cluster analysis were performed to investigate the associations between the bacterial combinations and clinical symptoms and signs using SAS 8.02. Seventy-seven samples (86%) yielded at least one of the 11 target species. Parvimonas micra (56%), Porphyromonas endodontalis (51%), Tannerella forsythia (48%), Prevotella intermedia (44%) and Porphyromonas gingivalis (37%) were the most prevalent taxa and were often concomitant. The following positive associations were found between the bacterial combinations and clinical features: P. endodontalis and T. forsythia with abscess; P. gingivalis and P. micra with sinus tract; P. gingivalis and P. endodontalis or P. micra and P. endodontalis with abscess and sinus tract; and the combination of P. endodontalis, P. micra, T. forsythia and P. gingivalis with sinus tract (P < 0.05). Various combinations of P. micra, P. endodontalis, T. forsythia and P. gingivalis may contribute to abscesses or sinus tracts of endodontic origin with bacterial synergism in a Chinese population. © 2015 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  13. Periodic Colony Formation by Bacterial Species Bacillus subtilis

    NASA Astrophysics Data System (ADS)

    Wakita, Jun-ichi; Shimada, Hirotoshi; Itoh, Hiroto; Matsuyama, Tohey; Matsushita, Mitsugu

    2001-03-01

    We have investigated the periodic colony growth of bacterial species Bacillus subtilis. A colony grows cyclically with the interface repeating an advance (migration phase) and a rest (consolidation phase) alternately on a surface of semi-solid agar plate under appropriate environmental conditions, resulting in a concentric ring-like colony. It was found from macroscopic observations that the characteristic quantities for the periodic growth such as the migration time, the consolidation time and the terrace spacing do not depend so much on nutrient concentration Cn, but do on agar concentration Ca. The consolidation time was a weakly increasing function of Ca, while the migration time and the terrace spacing were, respectively, weakly and strongly decreasing function of Ca. Overall, the cycle (migration-plus-consolidation) time seems to be constant, and does not depend so much on both Cn and Ca. Microscopically, bacterial cells inside the growing front of a colony keep increasing their population during both migration and consolidation phases. It was also confirmed that their secreting surfactant called surfactin does not affect their periodic growth qualitatively, i.e., mutant cells which cannot secrete surfactin produce a concentric ring-like colony. All these results suggest that the diffusion of the nutrient and the surfactin are irrelevant to their periodic growth.

  14. The in situ bacterial production of fluorescent organic matter; an investigation at a species level.

    PubMed

    Fox, B G; Thorn, R M S; Anesio, A M; Reynolds, D M

    2017-11-15

    Aquatic dissolved organic matter (DOM) plays an essential role in biogeochemical cycling and transport of organic matter throughout the hydrological continuum. To characterise microbially-derived organic matter (OM) from common environmental microorganisms (Escherichia coli, Bacillus subtilis and Pseudomonas aeruginosa), excitation-emission matrix (EEM) fluorescence spectroscopy was employed. This work shows that bacterial organisms can produce fluorescent organic matter (FOM) in situ and, furthermore, that the production of FOM differs at a bacterial species level. This production can be attributed to structural biological compounds, specific functional proteins (e.g. pyoverdine production by P. aeruginosa), and/or metabolic by-products. Bacterial growth curve data demonstrates that the production of FOM is fundamentally related to microbial metabolism. For example, the majority of Peak T fluorescence (> 75%) is shown to be intracellular in origin, as a result of the building of proteins for growth and metabolism. This underpins the use of Peak T as a measure of microbial activity, as opposed to bacterial enumeration as has been previously suggested. This study shows that different bacterial species produce a range of FOM that has historically been attributed to high molecular weight allochthonous material or the degradation of terrestrial FOM. We provide definitive evidence that, in fact, it can be produced by microbes within a model system (autochthonous), providing new insights into the possible origin of allochthonous and autochthonous organic material present in aquatic systems. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  15. Learning from Ethical Dilemmas.

    ERIC Educational Resources Information Center

    Havens, Mark D.

    1987-01-01

    Reports analysis of 60 case studies of ethical dilemmas faced by experiential educators. Identifies issues which enhance likelihood of moral dilemmas: funding, residential programming, and risk-taking. Exposes need for a professional "code of ethics." (NEC)

  16. Identification and characterization of bacterial symbionts in three species of filth fly parasitoids.

    PubMed

    Betelman, Kfir; Caspi-Fluger, Ayelet; Shamir, Maayan; Chiel, Elad

    2017-09-01

    Facultative bacterial symbionts are widespread among insects and have diverse effects on their biology. Here, we focused on bacterial symbionts of three ecologically and economically important filth flies parasitoid species-Spalangia cameroni, Spalangia endius and Muscidifurax raptor. Both Spalangia species harbored a Sodalis bacterium that is closely related to Spalangia praecaptivus (a free-living bacterium) and to Sodalis symbionts of weevils. This is the only case of Sodalis infection in the important order Hymenoptera. We also found, for the first time in this parasitoid guild, a Rickettsia infecting the two Spalangia spp., albeit in much higher prevalence in S. cameroni. Molecular and phylogenetic analyses revealed that it is closely related to Rickettsia felis and other Rickettsia species from the 'transitional' group. All three parasitoid species harbored Wolbachia. Using multi-locus sequence typing, we found that M. raptor harbors a single Wolbachia strain whereas the Spalangia spp. have multiple strains. By controlled crossings, we found that Wolbachia infection in S. endius causes incomplete cytoplasmic incompatibility and increased longevity, thereby promoting Wolbachia's spread. In contrast, no effects of Wolbachia on the reproduction and longevity of M. raptor were found. This study underscores the diversity and nature of symbiotic interactions between microbes and insects. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  17. Bacterial Species and Biochemical Characteristic Investigations of Nostoc flagelliforme Concentrates during its Storage.

    PubMed

    Yue, Lifang; Lv, Hexin; Zhen, Jing; Jiang, Shengping; Jia, Shiru; Shen, Shigang; Gao, Lu; Dai, Yujie

    2016-04-28

    Preservation of fresh algae plays an important role in algae seed subculture and aquaculture. The determination and examination of the changes of cell viability, composition, and bacterial species during storage would help to take suitable preservation methods to prolong the preservation time of fresh algae. Nostoc flagelliforme is a kind of edible cyanobacterium with important herbal and dietary values. This article investigated the changes of bacterial species and biochemical characteristics of fresh N. flagelliforme concentrate during natural storage. It was found that the viability of cells decreased along with the storage time. Fourteen bacteria strains in the algae concentrate were identified by PCR-DGGE and were grouped into four phyla, including Cyanobacteria, Firmicutes, Proteobacteria, and Bacteroidetes. Among them, Enterococcus viikkiensis may be a concern in the preservation. Eleven volatile organic compounds were identified from N. flagelliforme cells, in which geosmin could be treated as an indicator of the freshness of N. flagelliforme. The occurrence of indole compound may be an indicator of the degradation of cells.

  18. In vitro bacterial cytotoxicity of CNTs: reactive oxygen species mediate cell damage edges over direct physical puncturing.

    PubMed

    Rajavel, Krishnamoorthy; Gomathi, Rajkumar; Manian, Sellamuthu; Rajendra Kumar, Ramasamy Thangavelu

    2014-01-21

    Understanding the bacterial cytotoxicity of CNTs is important for a wide variety of applications in the biomedical, environmental, and health sectors. A majority of the earlier reports attributed the bactericidal cytotoxicity of CNTs to bacterial cell membrane damage by direct physical puncturing. Our results reveal that bacterial cell death via bacterial cell membrane damage is induced by reactive oxygen species (ROS) produced from CNTs and is not due to direct physical puncturing by CNTs. To understand the actual mechanism of bacterial killing, we elucidated the bacterial cytotoxicity of SWCNTs and MWCNTs against Gram-negative human pathogenic bacterial species Escherichia coli, Shigella sonnei, Klebsiella pneumoniae, and Pseudomonas aeruginosa and its amelioration upon functionalizing the CNTs with antioxidant tannic acid (TA). Interestingly, the bacterial cells treated with CNTs exhibited severe cell damage under laboratory (ambient) and sunlight irradiation conditions. However, CNTs showed no cytotoxicity to the bacterial cells when incubated in the dark. The quantitative assessments carried out by us made it explicit that CNTs are effective generators of ROS such as (1)O2, O2(•-), and (•)OH in an aqueous medium under both ambient and sunlight-irradiated conditions. Both naked and TA-functionalized CNTs showed negligible ROS production in the dark. Furthermore, strong correlations were obtained between ROS produced by CNTs and the bacterial cell mortality (with the correlation coefficient varying between 0.7618 and 0.9891) for all four tested pathogens. The absence of bactericidal cytotoxicity in both naked and functionalized CNTs in the dark reveals that the presence of ROS is the major factor responsible for the bactericidal action compared to direct physical puncturing. This understanding of the bactericidal activity of the irradiated CNTs, mediated through the generation of ROS, could be interesting for novel applications such as regulated ROS delivery

  19. Justice within social dilemmas.

    PubMed

    Schroeder, David A; Steel, Julie E; Woodell, Andria J; Bembenek, Alicia F

    2003-01-01

    The defining feature of social dilemma situations is the inherent conflict faced by those involved: should one act in his or her own individual best interest or sacrifice a measure of one's personal payoff to help maximize the joint payoff of the group as a whole? In such dilemmas, those making individualistic and defecting choices are always at a competitive advantage relative to those who choose to cooperate. One seemingly inevitable consequence of the resulting resource allocation asymmetry is that it must challenge and threaten the cooperator's sense of fairness and justice, and it is the reaction of those caught in social dilemmas to this injustice and unfairness that is the focus of this article. We examine how justice processes-distributive justice, procedural justice, restorative justice, and retributive justice-operate in social dilemmas. Within this examination, we consider ideas from classic and contemporary conceptual analyses of justice to provide a broader context within which to understand social dilemmas and the roles that justice plays as people strive to ensure fair outcomes for themselves and for others. We conclude with the proposal of a 4-stage, sequential model of justice in social dilemmas that posits groups move between the types of justice concerns when unfair and unsatisfactory outcomes (e.g., inequitable resource allocations, violations of agreed-on allocation rules, intentional and egregious exploitation of the group) cause members to "recognize the necessity" for change to ensure fair and just outcomes for all.

  20. The Unculturables: targeted isolation of bacterial species associated with canine periodontal health or disease from dental plaque.

    PubMed

    Davis, Ian J; Bull, Christopher; Horsfall, Alexander; Morley, Ian; Harris, Stephen

    2014-08-01

    The current inability to culture the entirety of observed bacteria is well known and with the advent of ever more powerful molecular tools, that can survey bacterial communities at previously unattainable depth, the gap in our capacity to culture and define all of these species increases exponentially. This gap has essentially become the rate limiting step in determining how the knowledge of which species are present in a sample can be applied to understand the role of these species in an ecosystem or disease process. A case in point is periodontal disease, which is the most widespread oral disease in dogs. If untreated the disease results in significant pain, eventual loss of the dentition and potentially an increased risk of systemic diseases. Previous molecular based studies have identified the bacterial species associated with periodontal disease in dogs; however without cultured strains from many of these species it has not been possible to study whether they play a role in the disease process. Using a quantitative polymerase chain reaction (qPCR) directed approach a range of microbiological media were screened and optimized to enrich for previously uncultivated target species. A systematic screening methodology was then employed to isolate the species of interest. In cases where the target species were not cultivable in isolation, helper strains grown underneath a nitrocellulose membrane were used to provide the necessary growth factors. This guided media optimization approach enabled the purification of 14 species, 8 of which we had previously been unable to cultivate in isolation. It is also applicable to the targeted isolation of isolates from species that have previously been cultured (for example to study intra-species variation) as demonstrated by the successful isolation of 6 targeted isolates of already cultured species. To our knowledge this is the first time this combination of qPCR guided media optimization, strategic screening and helper strain

  1. Molecular and Ecological Evidence for Species Specificity and Coevolution in a Group of Marine Algal-Bacterial Symbioses

    PubMed Central

    Ashen, Jon B.; Goff, Lynda J.

    2000-01-01

    The phylogenetic relationships of bacterial symbionts from three gall-bearing species in the marine red algal genus Prionitis (Rhodophyta) were inferred from 16S rDNA sequence analysis and compared to host phylogeny also inferred from sequence comparisons (nuclear ribosomal internal-transcribed-spacer region). Gall formation has been described previously on two species of Prionitis, P. lanceolata (from central California) and P. decipiens (from Peru). This investigation reports gall formation on a third related host, Prionitis filiformis. Phylogenetic analyses based on sequence comparisons place the bacteria as a single lineage within the Roseobacter grouping of the α subclass of the division Proteobacteria (99.4 to 98.25% sequence identity among phylotypes). Comparison of symbiont and host molecular phylogenies confirms the presence of three gall-bearing algal lineages and is consistent with the hypothesis that these red seaweeds and their bacterial symbionts are coevolving. The species specificity of these associations was investigated in nature by whole-cell hybridization of gall bacteria and in the laboratory by using cross-inoculation trials. Whole-cell in situ hybridization confirmed that a single bacterial symbiont phylotype is present in galls on each host. In laboratory trials, bacterial symbionts were incapable of inducing galls on alternate hosts (including two non-gall-bearing species). Symbiont-host specificity in Prionitis gall formation indicates an effective ecological separation between these closely related symbiont phylotypes and provides an example of a biological context in which to consider the organismic significance of 16S rDNA sequence variation. PMID:10877801

  2. Cheating fosters species co-existence in well-mixed bacterial communities

    PubMed Central

    Leinweber, Anne; Fredrik Inglis, R; Kümmerli, Rolf

    2017-01-01

    Explaining the enormous biodiversity observed in bacterial communities is challenging because ecological theory predicts that competition between species occupying the same niche should lead to the exclusion of less competitive community members. Competitive exclusion should be particularly strong when species compete for a single limiting resource or live in unstructured habitats that offer no refuge for weaker competitors. Here, we describe the ‘cheating effect’, a form of intra-specific competition that can counterbalance between-species competition, thereby fostering biodiversity in unstructured habitats. Using experimental communities consisting of the strong competitor Pseudomonas aeruginosa (PA) and its weaker counterpart Burkholderia cenocepacia (BC), we show that co-existence is impossible when the two species compete for a single limiting resource, iron. However, when introducing a PA cheating mutant, which specifically exploits the iron-scavenging siderophores produced by the PA wild type, we found that biodiversity was preserved under well-mixed conditions where PA cheats could outcompete the PA wild type. Cheating fosters biodiversity in our system because it creates strong intra-specific competition, which equalizes fitness differences between PA and BC. Our study identifies cheating – typically considered a destructive element – as a constructive force in shaping biodiversity. PMID:28060362

  3. Leadership Tensions and Dilemmas

    ERIC Educational Resources Information Center

    Edmunds, Bill; Mulford, Bill; Kendall, Diana; Kendall, Lawrie

    2008-01-01

    Results from the Tasmanian Successful School Principal Project (SSPP) survey concur with the four major leadership tensions and dilemmas identified in a background literature review. These tensions and dilemmas relate to internal/external control, ethic of care/responsibility, and an emphasis on professional/personal as well as…

  4. MOSAIC: an online database dedicated to the comparative genomics of bacterial strains at the intra-species level.

    PubMed

    Chiapello, Hélène; Gendrault, Annie; Caron, Christophe; Blum, Jérome; Petit, Marie-Agnès; El Karoui, Meriem

    2008-11-27

    The recent availability of complete sequences for numerous closely related bacterial genomes opens up new challenges in comparative genomics. Several methods have been developed to align complete genomes at the nucleotide level but their use and the biological interpretation of results are not straightforward. It is therefore necessary to develop new resources to access, analyze, and visualize genome comparisons. Here we present recent developments on MOSAIC, a generalist comparative bacterial genome database. This database provides the bacteriologist community with easy access to comparisons of complete bacterial genomes at the intra-species level. The strategy we developed for comparison allows us to define two types of regions in bacterial genomes: backbone segments (i.e., regions conserved in all compared strains) and variable segments (i.e., regions that are either specific to or variable in one of the aligned genomes). Definition of these segments at the nucleotide level allows precise comparative and evolutionary analyses of both coding and non-coding regions of bacterial genomes. Such work is easily performed using the MOSAIC Web interface, which allows browsing and graphical visualization of genome comparisons. The MOSAIC database now includes 493 pairwise comparisons and 35 multiple maximal comparisons representing 78 bacterial species. Genome conserved regions (backbones) and variable segments are presented in various formats for further analysis. A graphical interface allows visualization of aligned genomes and functional annotations. The MOSAIC database is available online at http://genome.jouy.inra.fr/mosaic.

  5. Towards a framework for the elicitation of dilemmas.

    PubMed

    Burger, Marc J C

    2008-08-01

    This paper covers the main findings of the doctoral research that was concerned with seeking to extend aspects of dilemma theory. In professional practice, the Trompenaars Hampden-Turner Dilemma Reconciliation Process(TM) is a vehicle delivering dilemma theory in application. It informs a manager or leader on how to explore the dilemmas they face, how to reconcile the tensions that result, and how to structure the action steps for implementing the reconciled solutions. This vehicle forms the professional practice of the author who seeks to bring more rigor to consulting practice and thereby also contribute to theory development in the domain. The critical review of dilemma theory reveals that previous authors are inconsistent and variously invalid in their use of the terms 'dilemma theory,' 'dilemma methodology,' 'dilemma process,' 'dilemma reconciliation,' etc., and therefore an attempt is made to resolve these inconsistencies by considering whether 'dilemmaism' at the meta-level might be positioned as a new paradigm of inquiry for (management) research that embodies ontological, epistemological, and methodical premises that frame an approach to the resolution of real world business problems in (multi) disciplinary; (multi) functional and (multi) cultural business environments. This research offers contributions to knowledge, professional practice and theory development from the exploration of the SPID model as a way to make the elicitation of dilemmas more rigorous and structured and in the broader context of exploring 'dilemmaism' as a new paradigm of inquiry.

  6. The Prisoner's Dilemma: Introducing Game Theory

    ERIC Educational Resources Information Center

    Shaw, Doug J.; Miller, Catherine M.

    2015-01-01

    Since 1950, the Prisoner's Dilemma has intrigued economists and amused fans of mathematics. It presents a situation in which two players acting to their own advantage do not do as well together as two players whose actions oppose their individual interests--hence, the dilemma. Variations of the Prisoner's Dilemma have appeared in diverse…

  7. Arthropod-borne bacterial diseases in pregnancy.

    PubMed

    Dotters-Katz, Sarah K; Kuller, Jeffrey; Heine, R Phillips

    2013-09-01

    Arthropod-borne bacterial diseases affect more than 25,000 Americans every year and thousands more around the world. These infections present a diagnostic dilemma for clinicians because they mimic many other pathologic conditions and are often low on or absent from the differential diagnosis list. Diagnosis is particularly challenging during pregnancy, as these infections may mimic common pregnancy-specific conditions, such as typical and atypical preeclampsia, or symptoms of pregnancy itself. Concerns regarding the safety in pregnancy of some indicated antibiotics add a therapeutic challenge for the prescriber, requiring knowledge of alternative therapeutic options for many arthropod-borne bacterial diseases. Physicians, especially those in endemic areas, must keep this class of infections in mind, particularly when the presentation does not appear classic for more commonly seen conditions. This article discusses presentation, diagnosis, and treatment of the most common of these arthropod-borne bacterial diseases, including Lyme disease, Rocky Mountain spotted fever, tick-borne relapsing fever, typhus, plague, cat-scratch disease, and Carrión disease.

  8. An X-ray Absorption Fine Structure study of Au adsorbed onto the non-metabolizing cells of two soil bacterial species

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Song, Zhen; Kenney, Janice P.L.; Fein, Jeremy B.

    2015-02-09

    Gram-positive and Gram-negative bacterial cells can remove Au from Au(III)-chloride solutions, and the extent of removal is strongly pH dependent. In order to determine the removal mechanisms, X-ray Absorption Fine Structure (XAFS) spectroscopy experiments were conducted on non-metabolizing biomass of Bacillus subtilis and Pseudomonas putida with fixed Au(III) concentrations over a range of bacterial concentrations and pH values. X-ray Absorption Near Edge Structure (XANES) and Extended X-ray Absorption Fine Structure (EXAFS) data on both bacterial species indicate that more than 90% of the Au atoms on the bacterial cell walls were reduced to Au(I). In contrast to what has beenmore » observed for Au(III) interaction with metabolizing bacterial cells, no Au(0) or Au-Au nearest neighbors were observed in our experimental systems. All of the removed Au was present as adsorbed bacterial surface complexes. For both species, the XAFS data suggest that although Au-chloride-hydroxide aqueous complexes dominate the speciation of Au in solution, Au on the bacterial cell wall is characterized predominantly by binding of Au atoms to sulfhydryl functional groups and amine and/or carboxyl functional groups, and the relative importance of the sulfhydryl groups increases with increasing pH and with decreasing Au loading. The XAFS data for both microorganism species suggest that adsorption is the first step in the formation of Au nanoparticles by bacteria, and the results enhance our ability to account for the behavior of Au in bacteria-bearing geologic systems.« less

  9. An X-ray Absorption Fine Structure study of Au adsorbed onto the non-metabolizing cells of two soil bacterial species

    NASA Astrophysics Data System (ADS)

    Song, Zhen; Kenney, Janice P. L.; Fein, Jeremy B.; Bunker, Bruce A.

    2012-06-01

    Gram-positive and Gram-negative bacterial cells can remove Au from Au(III)-chloride solutions, and the extent of removal is strongly pH dependent. In order to determine the removal mechanisms, X-ray Absorption Fine Structure (XAFS) spectroscopy experiments were conducted on non-metabolizing biomass of Bacillus subtilis and Pseudomonas putida with fixed Au(III) concentrations over a range of bacterial concentrations and pH values. X-ray Absorption Near Edge Structure (XANES) and Extended X-ray Absorption Fine Structure (EXAFS) data on both bacterial species indicate that more than 90% of the Au atoms on the bacterial cell walls were reduced to Au(I). In contrast to what has been observed for Au(III) interaction with metabolizing bacterial cells, no Au(0) or Au-Au nearest neighbors were observed in our experimental systems. All of the removed Au was present as adsorbed bacterial surface complexes. For both species, the XAFS data suggest that although Au-chloride-hydroxide aqueous complexes dominate the speciation of Au in solution, Au on the bacterial cell wall is characterized predominantly by binding of Au atoms to sulfhydryl functional groups and amine and/or carboxyl functional groups, and the relative importance of the sulfhydryl groups increases with increasing pH and with decreasing Au loading. The XAFS data for both microorganism species suggest that adsorption is the first step in the formation of Au nanoparticles by bacteria, and the results enhance our ability to account for the behavior of Au in bacteria-bearing geologic systems.

  10. Evolutionary Stability in the Traveler's Dilemma

    ERIC Educational Resources Information Center

    Barker, Andrew T.

    2009-01-01

    The traveler's dilemma is a generalization of the prisoner's dilemma which shows clearly a paradox of game theory. In the traveler's dilemma, the strategy chosen by analysis and theory seems obviously wrong intuitively. Here we develop a measure of evolutionary stability and show that the evolutionarily stable equilibrium is in some sense not very…

  11. EXPLOSIVE RADIATION OF A BACTERIAL SPECIES GROUP

    PubMed Central

    Morlon, Hélène; Kemps, Brian D.; Plotkin, Joshua B.; Brisson, Dustin

    2013-01-01

    The current diversity of life on earth is the product of macroevolutionary processes that have shaped the dynamics of diversification. Although the tempo of diversification has been studied extensively in macroorganisms, much less is known about the rates of diversification in the exceedingly diverse and species-rich microbiota. Decreases in diversification rates over time, a signature of explosive radiations, are commonly observed in plant and animal lineages. However, the few existing analyses of microbial lineages suggest that the tempo of diversification in prokaryotes may be fundamentally different. Here, we use multilocus and genomic sequence data to test hypotheses about the rate of diversification in a well-studied pathogenic bacterial lineage, Borrelia burgdorferi sensu lato (sl). Our analyses support the hypothesis that an explosive radiation of lineages occurred near the origin of the clade, followed by a sharp decay in diversification rates. These results suggest that explosive radiations may be a general feature of evolutionary history across the tree of life. PMID:22834754

  12. Diversity of bacterial species in the nasal cavity of sheep in the highlands of Ethiopia and first report of Histophilus somni in the country.

    PubMed

    Tesfaye, Biruk; Sisay Tessema, Tesfaye; Tefera, Genene

    2013-06-01

    A study was conducted to isolate bacterial species/pathogens from the nasal cavity of apparently healthy and pneumonic sheep. Nasal swabs were collected aseptically, transported in tryptose soya broth and incubated for 24 h. Then, each swab was streaked onto chocolate and blood agar for culture. Bacterial species were identified following standard bacteriological procedures. Accordingly, a total of 1,556 bacteria were isolated from 960 nasal swabs collected from three different highland areas of Ethiopia, namely Debre Berhan, Asella, and Gimba. In Debre Berhan, 140 Mannheimia haemolytica, 81 Histophilus somni, 57 Staphylococcus species, and 52 Bibersteinia trehalosi were isolated. While from Gimba M. haemolytica, Staphylococcus, Streptococcus, and H. somni were isolated at rates of 25.2, 15.9, 11.4, and 5.9 %, respectively, of the total 647 bacterial species. In Asella from 352 bacterial species isolated, 93 (26.4 %) were M. haemolytica, 48 (13.6 %) were Staphylococcus species, 26 (7.4 %) were B. trehalosi, and 17 (4.8 %) H. somni were recognized. Further identification and characterization using BIOLOG identification system Enterococcus avium and Sphingomonas sanguinis were identified at 100 % probability, while, H. somni and Actinobacillus lignerisii were suggested by the system. The study showed that a variety of bacterial species colonize the nasal cavity of the Ethiopian highland sheep with variable proportion between healthy and pneumonic ones. To our knowledge, this is the first report on isolation of H. somni, an important pathogen in cattle, from the respiratory tract of a ruminant species in the country.

  13. Diversity of the dominant bacterial species on sliced cooked pork products at expiration date in the Belgian retail.

    PubMed

    Geeraerts, Wim; Pothakos, Vasileios; De Vuyst, Luc; Leroy, Frédéric

    2017-08-01

    Pork-based cooked products, such as cooked hams, are economically valuable foods that are vulnerable to bacterial spoilage, even when applying cooling and modified atmosphere packaging (MAP). Besides a common presence of Brochothrix thermosphacta, their microbiota are usually dominated by lactic acid bacteria (LAB). Yet, the exact LAB species diversity can differ considerably among products. In this study, 42 sliced cooked pork samples were acquired from three different Belgian supermarkets to map their bacterial heterogeneity. The community compositions of the dominant bacterial species were established by analysing a total of 702 isolates from selective agar media by (GTG) 5 -PCR fingerprinting followed by gene sequencing. Most of the isolates belonged to the genera Carnobacterium, Lactobacillus, and Leuconostoc, with Leuconostoc carnosum and Leuconostoc gelidum subsp. gelidum being the most dominant members. The diversity of the dominant bacterial species varied when comparing samples from different production facilities and, in some cases, even within the same product types. Although LAB consistently dominated the microbiota of sliced cooked pork products in the Belgian market, results indicated that bacterial diversity needs to be addressed on the level of product composition and batch variation. Dedicated studies will be needed to substantiate potential links between such variability and microbial composition. For instance, the fact that higher levels of lactobacilli were associated with the presence of potassium lactate (E326) may be suggestive of selective pressure but needs to be validated, as this finding referred to a single product only. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. N-Acetyl-L-cysteine Effects on Multi-species Oral Biofilm Formation and Bacterial Ecology

    PubMed Central

    Rasmussen, Karin; Nikrad, Julia; Reilly, Cavan; Li, Yuping; Jones, Robert S.

    2015-01-01

    Future therapies for the treatment of dental decay have to consider the importance of preserving bacterial ecology while reducing biofilm adherence to teeth. A multi-species plaque derived (MSPD) biofilm model was used to assess how concentrations of N-acetyl-L-cysteine (0, 0.1%, 1%, 10%) affected the growth of complex oral biofilms. Biofilms were grown (n=96) for 24 hours on hydroxyapatite disks in BMM media with 0.5% sucrose. Bacterial viability and biomass formation was examined on each disk using a microtiter plate reader. In addition, fluorescence microscopy and Scanning Electron Microscopy was used to qualitatively examine the effect of NAC on bacterial biofilm aggregation, extracellular components, and bacterial morphology. The total biomass was significantly decreased after exposure of both 1% (from 0.48, with a 95% confidence interval of (0.44, 0.57) to 0.35, with confidence interval (0.31, 0.38)) and 10% NAC (0.14 with confidence interval (0.11, 0.17)). 16S rRNA amplicon sequencing analysis indicated that 1% NAC reduced biofilm adherence while preserving biofilm ecology. PMID:26518358

  15. Plant-associated bacterial populations on native and invasive plant species: comparisons between 2 freshwater environments.

    PubMed

    Olapade, Ola A; Pung, Kayleigh

    2012-06-01

    Plant-microbial interactions have been well studied because of the ecological importance of such relationships in aquatic systems. However, general knowledge regarding the composition of these biofilm communities is still evolving, partly as a result of several confounding factors that are attributable to plant host properties and to hydrodynamic conditions in aquatic environments. In this study, the occurrences of various bacterial phylogenetic taxa on 2 native plants, i.e., mayapple (Podophyllum peltatum L.) and cow parsnip (Heracleum maximum Bartram), and on an invasive species, i.e., garlic mustard (Alliaria petiolata (M. Bieb.) Cavara & Grande), were quantitatively examined using nucleic acid staining and fluorescence in situ hybridization. The plants were incubated in triplicates for about a week within the Kalamazoo River and Pierce Cedar Creek as well as in microcosms. The bacterial groups targeted for enumeration are known to globally occur in relatively high abundance and are also ubiquitously distributed in freshwater environments. Fluorescence in situ hybridization analyses of the bacterioplankton assemblages revealed that the majority of bacterial cells that hybridized with the different probes were similar between the 2 sites. In contrast, the plant-associated populations while similar on the 3 plants incubated in Kalamazoo River, their representations were highest on the 2 native plants relative to the invasive species in Pierce Cedar Creek. Overall, our results further suggested that epiphytic bacterial assemblages are probably under the influences of and probably subsequently respond to multiple variables and conditions in aquatic milieus.

  16. Efficiencies of Recovery of Bdellovibrios from Brackish- Water Environments by Using Various Bacterial Species as Prey

    PubMed Central

    Schoeffield, A. J.; Williams, H. N.

    1990-01-01

    A total of 44 bacterial species subdivided into 10 trial experiments have been used as prey for the recovery of bdellovibrios from samples of water from a brackish tidal pond and an aquarium saltwater tank. In an initial investigation, the recovery efficiency of each of the test bacterial species was compared with that of a designated standard prey, Vibrio parahaemolyticus P-5. The results revealed that in each case strain P-5 yielded an equal or significantly greater number of plaques of bdellovibrios than the test prey with but a single exception, strain CS5. In repeat experiments, CS5 yielded fewer plaques than P-5. To determine whether the use of multiple bacterial species compared with a single species as prey would increase the number of PFU of bdellovibrios recovered, material from plaques appearing on each of the test prey in the respective trials was sequentially subcultured onto two respective agar plates, the first containing as prey V. parahaemolyticus P-5 and the second containing the initial test organism. In nearly every case, subculture of plaques from lawns of the test prey to P-5 resulted in plaque formation. On the basis of the results, the use of several test prey and P-5 did not result in the recovery of any more bdellovibrio PFU than the use of P-5 alone. In this study, V. parahaemolyticus P-5 was observed to be the most efficient prey for the recovery of bdellovibrios from moderate salt water. PMID:16348096

  17. Microbiological and molecular identification of bacterial species isolated from nasal and oropharyngeal mucosa of fuel workers in Riyadh, Saudi Arabia.

    PubMed

    AlWakeel, Suaad S

    2017-09-01

    This study aimed to determine the bacterial species colonizing the nasal and oropharyngeal mucosa of fuel workers in Central Riyadh, Saudi Arabia on a microbiological and molecular level. Throat and nasal swab samples were obtained from 29 fuel station attendants in the period of time extending from March to May 2014 in Riyadh, Saudi Arabia. Microbiological identification techniques were utilized to identify the bacterial species isolated. Antibiotic sensitivity was assessed for each of the bacterial isolates. Molecular identification techniques based on PCR analysis of specific genomic sequences was conducted and was the basis on which phylogeny representation was done for 10 randomly selected samples of the isolates. Blood was drawn and a complete blood count was conducted to note the hematological indices for each of the study participants. Nineteen bacterial species were isolated from both the nasal cavity and the oropharynx including Streptococcus thoraltensis , alpha-hemolytic streptococci, Staphylococcus hominis , coagulase-negative staphylococci, Leuconostoc mesenteroides , Erysipelothrix rhusiopathiae and several others. We found 100% sensitivity of the isolates to ciprofloxacin, cefuroxime and gentamicin. Whereas cefotaxime and azithromycin posted sensitivities of 85.7% and 91.4%, respectively. Low sensitivities (<60% sensitivity) to the antibiotics ampicillin, erythromycin, clarithromycin and norfloxacin were observed. Ninety-seven percent similarity to the microbial bank species was noted when the isolates were compared to it. Most hematological indices recorded were within the normal range. In conclusion, exposure to toxic fumes and compounds within fuel products may be a contributing factor to bacterial colonization of the respiratory tract in fuel workers.

  18. Characterization of the spoilage potential of pure and mixed cultures of bacterial species isolated from tropical yellowfin tuna (Thunnus albacares).

    PubMed

    Silbande, A; Cornet, J; Cardinal, M; Chevalier, F; Rochefort, K; Smith-Ravin, J; Adenet, S; Leroi, F

    2018-02-01

    The spoilage potential of 28 bacterial strains isolated from spoiled raw yellowfin tuna was evaluated. Bacterial species were inoculated in irradiated tuna matrix. Chemical changes, bacterial growth and sensory quality were monitored during aerobic storage at 8°C. Pseudomonas spp., Enterobacter spp. and Escherichia hermanii had no spoiling effect. Brochothrix thermosphacta and Carnobacterium divergens/maltaromaticum developed moderate unpleasant odours. Hafnia paralvei and Serratia spp. released strong off-odours (pyrrolidine, sulphur/cabbage). No bacterial group (except H. paralvei) combined with Pseudomonas spp. deteriorated the sensory quality of tuna. When C. divergens/maltaromaticum was associated with H. paralvei or B. thermosphacta, the odour is close to the naturally contaminated tuna stored on the same conditions. The pH, total volatile basic nitrogen (TVBN) and trimethylamine (TMA) were not correlated with the spoilage. The bacterial species had a different impact on the sensory quality of the fish. The bacterial interactions lead to an enhancement or an inhibition of the spoilage potential and the bacterial growth. The specific spoilage organism (SSO) appears to be an association of lactic acid bacteria (LAB) with Enterobacteriaceae or B. thermosphacta. Pseudomonas, often dominant at the sensory rejection time, is not a good quality indicator. © 2017 The Society for Applied Microbiology.

  19. Moral Dilemmas in Pediatric Orthopedics.

    PubMed

    Mercuri, John J; Vigdorchik, Jonathan M; Otsuka, Norman Y

    2015-12-01

    All orthopedic surgeons face moral dilemmas on a regular basis; however, little has been written about the moral dilemmas that are encountered when providing orthopedic care to pediatric patients and their families. This article aims to provide surgeons with a better understanding of how bioethics and professionalism apply to the care of their pediatric patients. First, several foundational concepts of both bioethics and professionalism are summarized, and definitions are offered for 16 important terms within the disciplines. Next, some of the unique aspects of pediatric orthopedics as a subspecialty are reviewed before engaging in a discussion of 5 common moral dilemmas within the field. Those dilemmas include the following: (1) obtaining informed consent and assent for either surgery or research from pediatric patients and their families; (2) performing cosmetic surgery on pediatric patients; (3) caring for pediatric patients with cognitive or physical impairments; (4) caring for injured pediatric athletes; and (5) meeting the demand for pediatric orthopedic care in the United States. Pertinent considerations are reviewed for each of these 5 moral dilemmas, thereby better preparing surgeons for principled moral decision making in their own practices. Each of these dilemmas is inherently complex with few straightforward answers; however, orthopedic surgeons have an obligation to take the lead and better define these kinds of difficult issues within their field. The lives of pediatric patients and their families will be immeasurably improved as a result. Copyright 2015, SLACK Incorporated.

  20. Epithelial cell pro-inflammatory cytokine response differs across dental plaque bacterial species.

    PubMed

    Stathopoulou, Panagiota G; Benakanakere, Manjunatha R; Galicia, Johnah C; Kinane, Denis F

    2010-01-01

    The dental plaque is comprised of numerous bacterial species, which may or may not be pathogenic. Human gingival epithelial cells (HGECs) respond to perturbation by various bacteria of the dental plaque by production of different levels of inflammatory cytokines, which is a putative reflection of their virulence. The aim of the current study was to determine responses in terms of interleukin (IL)-1beta, IL-6, IL-8 and IL-10 secretion induced by Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum and Streptococcus gordonii in order to gauge their virulence potential. HGECs were challenged with the four bacterial species, live or heat killed, at various multiplicity of infections and the elicited IL-1beta, IL-6, IL-8 and IL-10 responses were assayed by enzyme-linked immunosorbent assay. Primary HGECs challenged with live P. gingivalis produced high levels of IL-1beta, while challenge with live A. actinomycetemcomitans gave high levels of IL-8. The opportunistic pathogen F. nucleatum induces the highest levels of pro-inflammatory cytokines, while the commensal S. gordonii is the least stimulatory. We conclude that various dental plaque biofilm bacteria induce different cytokine response profiles in primary HGECs that may reflect their individual virulence or commensal status.

  1. Limitations to estimating bacterial cross-species transmission using genetic and genomic markers: inferences from simulation modeling

    PubMed Central

    Benavides, Julio A; Cross, Paul C; Luikart, Gordon; Creel, Scott

    2014-01-01

    Cross-species transmission (CST) of bacterial pathogens has major implications for human health, livestock, and wildlife management because it determines whether control actions in one species may have subsequent effects on other potential host species. The study of bacterial transmission has benefitted from methods measuring two types of genetic variation: variable number of tandem repeats (VNTRs) and single nucleotide polymorphisms (SNPs). However, it is unclear whether these data can distinguish between different epidemiological scenarios. We used a simulation model with two host species and known transmission rates (within and between species) to evaluate the utility of these markers for inferring CST. We found that CST estimates are biased for a wide range of parameters when based on VNTRs and a most parsimonious reconstructed phylogeny. However, estimations of CST rates lower than 5% can be achieved with relatively low bias using as low as 250 SNPs. CST estimates are sensitive to several parameters, including the number of mutations accumulated since introduction, stochasticity, the genetic difference of strains introduced, and the sampling effort. Our results suggest that, even with whole-genome sequences, unbiased estimates of CST will be difficult when sampling is limited, mutation rates are low, or for pathogens that were recently introduced. PMID:25469159

  2. Species and Scale Dependence of Bacterial Motion Dynamics

    NASA Astrophysics Data System (ADS)

    Sund, N. L.; Yang, X.; Parashar, R.; Plymale, A.; Hu, D.; Kelly, R.; Scheibe, T. D.

    2017-12-01

    Many metal reducing bacteria are motile with their motion characteristics described by run-and-tumble behavior exhibiting series of flights (jumps) and waiting (residence) time spanning a wide range of values. Accurate models of motility allow for improved design and evaluation of in-situ bioremediation in the subsurface. While many bioremediation models neglect the motion of the bacteria, others treat motility using an advection dispersion equation, which assumes that the motion of the bacteria is Brownian.The assumption of Brownian motion to describe motility has enormous implications on predictive capabilities of bioremediation models, yet experimental evidence of this assumption is mixed [1][2][3]. We hypothesize that this is due to the species and scale dependence of the motion dynamics. We test our hypothesis by analyzing videos of motile bacteria of five different species in open domains. Trajectories of individual cells ranging from several seconds to few minutes in duration are extracted in neutral conditions (in the absence of any chemical gradient). The density of the bacteria is kept low so that the interaction between the bacteria is minimal. Preliminary results show a transition from Fickian (Brownian) to non-Fickian behavior for one species of bacteria (Pelosinus) and persistent Fickian behavior of another species (Geobacter).Figure: Video frames of motile bacteria with the last 10 seconds of their trajectories drawn in red. (left) Pelosinus and (right) Geobacter.[1] Ariel, Gil, et al. "Swarming bacteria migrate by Lévy Walk." Nature Communications 6 (2015).[2] Saragosti, Jonathan, Pascal Silberzan, and Axel Buguin. "Modeling E. coli tumbles by rotational diffusion. Implications for chemotaxis." PloS one 7.4 (2012): e35412.[3] Wu, Mingming, et al. "Collective bacterial dynamics revealed using a three-dimensional population-scale defocused particle tracking technique." Applied and Environmental Microbiology 72.7 (2006): 4987-4994.

  3. Ethical dilemmas in community mental health care.

    PubMed

    Liégeois, A; Van Audenhove, C

    2005-08-01

    Ethical dilemmas in community mental health care is the focus of this article. The dilemmas are derived from a discussion of the results of a qualitative research project that took place in five countries of the European Union. The different stakeholders are confronted with the following dilemmas: community care versus hospital care (clients); a life with care versus a life without care (informal carers); stimulation of the client toward greater responsibility versus protection against such responsibility (professionals); budgetary control versus financial incentives (policy makers), and respect for the client versus particular private needs (neighbourhood residents). These dilemmas are interpreted against the background of a value based ethical model. This model offers an integral approach to the dilemmas and can be used to determine policy. The dilemmas are discussed here as the result of conflicting values-namely autonomy and privacy, support and safety, justice and participation, and trust and solidarity.

  4. [Ethical dilemmas of contemporary psychiatry].

    PubMed

    Filaković, Pavo; Pozgain, Ivan

    2008-01-01

    Ethics in the contemporary psychiatry, as well as in medicine in general, is based on the two core ethical traditions: deontological and theological. Good ethical decision takes into the consideration both traditions, and is preceded with ethical dilemmas to provide the best possible care to the patients in that moment. In the article are presented most recent research results of the literature about ethical dilemmas in psychiatry. Ethical dilemmas in everyday practice as well as compliance with the patients, psychiatric consultations, informed consent, treatment of personality disorders, pharmacological investigations, forensic psychiatry, forced hospitalisation, promotion of mental health, and dealing with the stigma of the mental diseases are showed in the article. The authors emphasize the necessity of constant questioning of ethical dilemmas in the contemporary psychiatry, because of the special status of psychiatry as a potentially risky field in practice, and because of intensive pharmacological investigations in psychiatric patients.

  5. Social dilemmas in multistrategy evolutionary potential games

    NASA Astrophysics Data System (ADS)

    Szabó, György; Bunth, Gergely

    2018-01-01

    The nature of social dilemmas is studied in n -strategy evolutionary potential games on a square lattice with nearest-neighbor interactions and the logit rule. For symmetric games with symmetric payoff matrices there are no dilemmas because of the coincidence of individual and common interests. The dilemmas are caused by the antisymmetric parts of the self- and cross-dependent payoff components if it modifies the preferred Nash equilibrium. The contentment of players and the emergence of dilemmas in the preferred Nash equilibria are illustrated on some two-dimensional cross sections of the parameter space.

  6. The Nuclear and Mitochondrial Genomes of the Facultatively Eusocial Orchid Bee Euglossa dilemma

    PubMed Central

    Brand, Philipp; Saleh, Nicholas; Pan, Hailin; Li, Cai; Kapheim, Karen M.; Ramírez, Santiago R.

    2017-01-01

    Bees provide indispensable pollination services to both agricultural crops and wild plant populations, and several species of bees have become important models for the study of learning and memory, plant–insect interactions, and social behavior. Orchid bees (Apidae: Euglossini) are especially important to the fields of pollination ecology, evolution, and species conservation. Here we report the nuclear and mitochondrial genome sequences of the orchid bee Euglossa dilemma Bembé & Eltz. E. dilemma was selected because it is widely distributed, highly abundant, and it was recently naturalized in the southeastern United States. We provide a high-quality assembly of the 3.3 Gb genome, and an official gene set of 15,904 gene annotations. We find high conservation of gene synteny with the honey bee throughout 80 MY of divergence time. This genomic resource represents the first draft genome of the orchid bee genus Euglossa, and the first draft orchid bee mitochondrial genome, thus representing a valuable resource to the research community. PMID:28701376

  7. The Nuclear and Mitochondrial Genomes of the Facultatively Eusocial Orchid Bee Euglossa dilemma.

    PubMed

    Brand, Philipp; Saleh, Nicholas; Pan, Hailin; Li, Cai; Kapheim, Karen M; Ramírez, Santiago R

    2017-09-07

    Bees provide indispensable pollination services to both agricultural crops and wild plant populations, and several species of bees have become important models for the study of learning and memory, plant-insect interactions, and social behavior. Orchid bees (Apidae: Euglossini) are especially important to the fields of pollination ecology, evolution, and species conservation. Here we report the nuclear and mitochondrial genome sequences of the orchid bee Euglossa dilemma Bembé & Eltz. E. dilemma was selected because it is widely distributed, highly abundant, and it was recently naturalized in the southeastern United States. We provide a high-quality assembly of the 3.3 Gb genome, and an official gene set of 15,904 gene annotations. We find high conservation of gene synteny with the honey bee throughout 80 MY of divergence time. This genomic resource represents the first draft genome of the orchid bee genus Euglossa , and the first draft orchid bee mitochondrial genome, thus representing a valuable resource to the research community. Copyright © 2017 Brand et al.

  8. Loofah sponges as reservoirs and vehicles in the transmission of potentially pathogenic bacterial species to human skin.

    PubMed Central

    Bottone, E J; Perez, A A; Oeser, J L

    1994-01-01

    Loofah sponges are natural products used as exfoliative beauty aids. As a consequence of tracing a case of Pseudomonas aeruginosa folliculitis to a contaminated loofah sponge, we assessed the role of loofah sponges in supporting the growth of a wide variety of bacterial species. Our data show growth enhancement of sterile loofah fragments for numerous gram-negative (Pseudomonas, Xanthomonas, and Klebsiella) and gram-positive (Enterococcus and group B Streptococcus) species of human and environmental origin. Furthermore, hydrated new, unused loofah sponges undergo a shift in bacterial flora from sparse colonies of Bacillus spp. and Staphylococcus epidermidis to a predominantly gram-negative flora. The growth-promoting potential of loofah sponges (and other exfoliatives) can be further augmented by desquamated epithelial cells entrapped in the loofah fibrous matrix. Therefore, as loofah sponges (and other exfoliatives) can serve as a reservoir and a vehicle for the transmission of potentially pathogenic species to the human skin, we recommend their decontamination with hypochlorite (10%) bleach at regular intervals. Images PMID:8150959

  9. Loofah sponges as reservoirs and vehicles in the transmission of potentially pathogenic bacterial species to human skin.

    PubMed

    Bottone, E J; Perez, A A; Oeser, J L

    1994-02-01

    Loofah sponges are natural products used as exfoliative beauty aids. As a consequence of tracing a case of Pseudomonas aeruginosa folliculitis to a contaminated loofah sponge, we assessed the role of loofah sponges in supporting the growth of a wide variety of bacterial species. Our data show growth enhancement of sterile loofah fragments for numerous gram-negative (Pseudomonas, Xanthomonas, and Klebsiella) and gram-positive (Enterococcus and group B Streptococcus) species of human and environmental origin. Furthermore, hydrated new, unused loofah sponges undergo a shift in bacterial flora from sparse colonies of Bacillus spp. and Staphylococcus epidermidis to a predominantly gram-negative flora. The growth-promoting potential of loofah sponges (and other exfoliatives) can be further augmented by desquamated epithelial cells entrapped in the loofah fibrous matrix. Therefore, as loofah sponges (and other exfoliatives) can serve as a reservoir and a vehicle for the transmission of potentially pathogenic species to the human skin, we recommend their decontamination with hypochlorite (10%) bleach at regular intervals.

  10. Combined chemical and physical transformation method with RbCl and sepiolite for the transformation of various bacterial species.

    PubMed

    Ren, Jun; Lee, Haram; Yoo, Seung Min; Yu, Myeong-Sang; Park, Hansoo; Na, Dokyun

    2017-04-01

    DNA transformation that delivers plasmid DNAs into bacterial cells is fundamental in genetic manipulation to engineer and study bacteria. Developed transformation methods to date are optimized to specific bacterial species for high efficiency. Thus, there is always a demand for simple and species-independent transformation methods. We herein describe the development of a chemico-physical transformation method that combines a rubidium chloride (RbCl)-based chemical method and sepiolite-based physical method, and report its use for the simple and efficient delivery of DNA into various bacterial species. Using this method, the best transformation efficiency for Escherichia coli DH5α was 4.3×10 6 CFU/μg of pUC19 plasmid, which is higher than or comparable to the reported transformation efficiencies to date. This method also allowed the introduction of plasmid DNAs into Bacillus subtilis (5.7×10 3 CFU/μg of pSEVA3b67Rb), Bacillus megaterium (2.5×10 3 CFU/μg of pSPAsp-hp), Lactococcus lactis subsp. lactis (1.0×10 2 CFU/μg of pTRKH3-ermGFP), and Lactococcus lactis subsp. cremoris (2.2×10 2 CFU/μg of pMSP3535VA). Remarkably, even when the conventional chemical and physical methods failed to generate transformed cells in Bacillus sp. and Enterococcus faecalis, E. malodoratus and E. mundtii, our combined method showed a significant transformation efficiency (2.4×10 4 , 4.5×10 2 , 2×10 1 , and 0.5×10 1 CFU/μg of plasmid DNA). Based on our results, we anticipate that our simple and efficient transformation method should prove usefulness for introducing DNA into various bacterial species without complicated optimization of parameters affecting DNA entry into the cell. Copyright © 2017. Published by Elsevier B.V.

  11. Cultural Values in Intergroup and Single-Group Social Dilemmas.

    PubMed

    Probst; Carnevale; Triandis

    1999-03-01

    Do cultural values influence the manner in which people cooperate with one another? This study assessed cultural characteristics of individuals and then related these characteristics to cooperative behavior in social dilemmas. Participants were assessed for their degree of vertical and horizontal individualism and collectivism, cultural values identified by Triandis (1995). They made choices in either a single-group or an intergroup social dilemma. The single-group dilemma entailed a three-person dilemma; the intergroup dilemma was identical but added subgroup competition, i.e., an opposing three-person group. The results indicated an interaction between cultural characteristics and type of dilemma for cooperation. The single-group versus intergroup effect reported by Bornstein and Ben-Yossef (1994) was replicated, but only for vertical individualists. The vertical individualists were least cooperative in the single-group dilemma but were more cooperative in the intergroup dilemma-where cooperation with the group maximized personal outcomes. The vertical collectivists were most cooperative in the single-group dilemma but were less cooperative in the intergroup dilemma- where group defection resulted in maximum group outcomes. The horizontal individualists and collectivists exhibited an intermediate level of cooperation, with no differences in cooperation between the single-group and intergroup dilemmas. Taken together, the results suggest that the relationship between cultural values and cooperation, in particular with reference to vertical and horizontal components of individualism and collectivism, is more complex than has been suggested in past research. Copyright 1999 Academic Press.

  12. Moral judgment reloaded: a moral dilemma validation study

    PubMed Central

    Christensen, Julia F.; Flexas, Albert; Calabrese, Margareta; Gut, Nadine K.; Gomila, Antoni

    2014-01-01

    We propose a revised set of moral dilemmas for studies on moral judgment. We selected a total of 46 moral dilemmas available in the literature and fine-tuned them in terms of four conceptual factors (Personal Force, Benefit Recipient, Evitability, and Intention) and methodological aspects of the dilemma formulation (word count, expression style, question formats) that have been shown to influence moral judgment. Second, we obtained normative codings of arousal and valence for each dilemma showing that emotional arousal in response to moral dilemmas depends crucially on the factors Personal Force, Benefit Recipient, and Intentionality. Third, we validated the dilemma set confirming that people's moral judgment is sensitive to all four conceptual factors, and to their interactions. Results are discussed in the context of this field of research, outlining also the relevance of our RT effects for the Dual Process account of moral judgment. Finally, we suggest tentative theoretical avenues for future testing, particularly stressing the importance of the factor Intentionality in moral judgment. Additionally, due to the importance of cross-cultural studies in the quest for universals in human moral cognition, we provide the new set dilemmas in six languages (English, French, German, Spanish, Catalan, and Danish). The norming values provided here refer to the Spanish dilemma set. PMID:25071621

  13. Fundamental dilemmas in contemporary psychotherapy: a transtheoretical concept.

    PubMed

    Scaturo, Douglas J

    2002-01-01

    The transtheoretical nature of fundamental dilemmas in contemporary psychotherapy is explored. The basic distinction between technical and ethical dilemmas in clinical practice is discussed, as well as the ramifications for the psychotherapist. Clinical dilemmas identified by survey research studies and interviews with master psychotherapists are reviewed. In addition to dilemmas relevant to circumscribed areas of psychotherapy, such as brief therapy, managed mental health care, sexual questions, feminist therapy, dilemmas fundamental to the psychotherapeutic process as a whole are examined. Finally, clinical examples are provided that include such issues as hospitalization of the suicidal patient, dealing with known contraindications, treating the intractable patient, and self-care of the psychotherapist.

  14. Turkish Teachers' Accounts of Moral Dilemmas in Early Childhood Settings

    ERIC Educational Resources Information Center

    Koc, Kevser; Buzzelli, Cary A.

    2016-01-01

    In all, 26 Turkish early childhood educators were asked to describe a moral dilemma they faced in their classroom, the circumstances that made the situation a dilemma, and why it was a moral dilemma. The dilemmas described arose from conflicts between teachers and children, teachers and parents, and teachers and administrators. Dilemmas described…

  15. Diversity and localization of bacterial symbionts in three whitefly species (Hemiptera: Aleyrodidae) from the east coast of the Adriatic Sea.

    PubMed

    Skaljac, M; Zanić, K; Hrnčić, S; Radonjić, S; Perović, T; Ghanim, M

    2013-02-01

    Several whitefly species (Hemiptera: Aleyrodidae) are cosmopolitan phloem-feeders that cause serious damage in numerous agricultural crops. All whitefly species harbor a primary bacterial symbiont and a diverse array of secondary symbionts which may influence several aspects of the insect's biology. We surveyed infections by secondary symbionts in Bemisia tabaci (Gennadius), Trialeurodes vaporariorum (Westwood) and Siphoninus phillyreae (Haliday) from areas in the east cost of the Adriatic Sea. Both the Middle East-Asia Minor 1 (MEAM1) and Mediterranean (MED) B. tabaci genetic groups were detected in Montenegro, whereas only the MED was confirmed in Croatia. Trialeurodes vaporariorum and S. phillyreae were found in all areas surveyed. MEAM1 and MED exhibited similarity to previously reported infections, while populations of T. vaporariorum from Montenegro harbored Rickettsia, Wolbachia and Cardinium in addition to previously reported Hamiltonella and Arsenopnohus. Siphoninus phillyreae harbored Hamiltonella, Wolbachia, Cardinium and Arsenophonus, with the latter appearing in two alleles. Multiple infections of all symbionts were common in the three insect species tested, with some reaching near fixation. Florescent in situ hybridization showed new localization patterns for Hamiltonella in S. phillyreae, and the morphology of the bacteriosome differed from that observed in other whitefly species. Our results show new infections with bacterial symbionts in the whitefly species studied. Infections with the same symbionts in reproductively isolated whitefly species confirm complex relationships between whiteflies and bacterial symbionts, and suggest possible horizontal transfer of some of these bacteria.

  16. The dilemma of female mate selection in the brown bear, a species with sexually selected infanticide

    PubMed Central

    Bellemain, Eva; Zedrosser, Andreas; Manel, Stéphanie; Waits, Lisette P; Taberlet, Pierre; Swenson, Jon E

    2005-01-01

    Because of differential investment in gametes between sexes, females tend to be the more selective sex. Based on this concept, we investigate mate selection in a large carnivore: the brown bear (Ursus arctos). We hypothesize that, in this species with sexually selected infanticide (SSI), females may be faced with a dilemma: either select a high-quality partner based on phenotypic criteria, as suggested by theories of mate choice, or rather mate with future potentially infanticidal males as a counter-strategy to SSI. We evaluated which male characteristics were important in paternity assignment. Among males available in the vicinity of the females, the largest, most heterozygous and less inbred and also the geographically closest males were more often the fathers of the female's next litter. We suggest that female brown bears may select the closest males as a counter-strategy to infanticide and exercise a post-copulatory cryptic choice, based on physical attributes, such as a large body size, reflecting male genetic quality. However, male–male competition either in the form of fighting before copulation or during the post-copulatory phase, in the form of sperm competition, cannot entirely be ruled out. PMID:16543170

  17. The French Strategic Dilemma.

    DTIC Science & Technology

    1984-03-01

    THE FRENCH STRATEGIC DILEMMA This paper identifies a basic strategic dilemma for France . On the one hand, French leaders identify the political purpose...are inducing a need for France to provide a more explicit definition of the role of French nuclear weapons in the West European security system. In...defense policy in France . This section concludes with an assessment of the alternative scenarios for the evolution of French defense policy in the 1980s

  18. Nurse middle manager ethical dilemmas and moral distress.

    PubMed

    Ganz, Freda D; Wagner, Nurit; Toren, Orly

    2015-02-01

    Nurse managers are placed in a unique position within the healthcare system where they greatly impact upon the nursing work environment. Ethical dilemmas and moral distress have been reported for staff nurses but not for nurse middle managers. To describe ethical dilemmas and moral distress among nurse middle managers arising from situations of ethical conflict. The Ethical Dilemmas in Nursing-Middle Manager Questionnaire and a personal characteristics questionnaire were administered to a convenience sample of middle managers from four hospitals in Israel. Middle managers report low to moderate levels of frequency and intensity of ethical dilemmas and moral distress. Highest scores were for administrative dilemmas. Middle managers experience lower levels of ethical dilemmas and moral distress than staff nurses, which are irrespective of their personal characteristics. Interventions should be developed, studied, and then incorporated into institutional frameworks in order to improve this situation. © The Author(s) 2014.

  19. Biomimetic/Optical Sensors for Detecting Bacterial Species

    NASA Technical Reports Server (NTRS)

    Homer, Margie; Ksendzov, Alexander; Yen, Shiao-Pin; Ryan, Margaret; Lazazzera, Beth

    2006-01-01

    Biomimetic/optical sensors have been proposed as means of real-time detection of bacteria in liquid samples through real-time detection of compounds secreted by the bacteria. Bacterial species of interest would be identified through detection of signaling compounds unique to those species. The best-characterized examples of quorum-signaling compounds are acyl-homoserine lactones and peptides. Each compound, secreted by each bacterium of an affected species, serves as a signal to other bacteria of the same species to engage in a collective behavior when the population density of that species reaches a threshold level analogous to a quorum. A sensor according to the proposal would include a specially formulated biomimetic film, made of a molecularly imprinted polymer (MIP), that would respond optically to the signaling compound of interest. The MIP film would be integrated directly onto an opticalwaveguide- based ring resonator for optical readout. Optically, the sensor would resemble the one described in Chemical Sensors Based on Optical Ring Resonators (NPO-40601), NASA Tech Briefs, Vol. 29, No. 10 (October 2005), page 32. MIPs have been used before as molecular- recognition compounds, though not in the manner of the present proposal. Molecular imprinting is an approach to making molecularly selective cavities in a polymer matrix. These cavities function much as enzyme receptor sites: the chemical functionality and shape of a cavity in the polymer matrix cause the cavity to bind to specific molecules. An MIP matrix is made by polymerizing monomers in the presence of the compound of interest (template molecule). The polymer forms around the template. After the polymer solidifies, the template molecules are removed from the polymer matrix by decomplexing them from their binding sites and then dissolving them, leaving cavities that are matched to the template molecules in size, shape, and chemical functionality. The cavities thus become molecular-recognition sites

  20. Vaginal lactobacilli inhibiting growth of Gardnerella vaginalis, Mobiluncus and other bacterial species cultured from vaginal content of women with bacterial vaginosis.

    PubMed

    Skarin, A; Sylwan, J

    1986-12-01

    On a solid agar medium the growth-inhibitory effect of 9 Lactobacillus strains cultured from vaginal content was tested on bacteria cultured from vaginal content of women with bacterial vaginosis: Mobiluncus, Gardnerella vaginalis, Bacteroides and anaerobic cocci. Inhibition zones were observed in the growth of all of the strains isolated from women with bacterial vaginosis around all lactobacilli. The inhibitory effect of the lactobacilli was further tested on various anaerobic and facultatively anaerobic species, both type strains and fresh extragenitally cultured strains. Four Bacteroides fragilis strains as well as 2 out of 4 Staphylococcus aureus strains were clearly inhibited by the lactobacilli. The inhibition zones were generally wider at pH 5.5 than at 6.0. For all inhibited strains, (the S. aureus excepted) a low pH on the agar around the lactobacilli correlated to wider growth-inhibition zones.

  1. Medical ethics and ethical dilemmas.

    PubMed

    Iyalomhe, G B S

    2009-01-01

    Ethical problems routinely arise in the hospital and outpatient practice settings and times of dilemma do occur such that practitioners and patients are at cross-roads where choice and decision making become difficult in terms of ethics. This paper attempts a synopsis of the basic principles of medical ethics, identifies some ethical dilemmas that doctors often encounter and discusses some strategies to address them as well as emphasizes the need for enhanced ethics education both for physicians and patients particularly in Nigeria. Literature and computer programmes (Medline and PsychoInfo databases) were searched for relevant information. The search showed that the fundamental principles suggested by ethicists to assist doctors to evaluate the ethics of a situation while making a decision include respect for autonomy, beneficence, non-maleficence and justice. Although the above principles do not give answers as to how to handle a particular situation, they serve as a guide to doctors on what principles ought to apply to actual circumstances. The principles sometimes conflict with each other leading to ethical dilemmas when applied to issues such as abortion, contraception, euthanasia, professional misconduct, confidentiality truth telling, professional relationship with relatives, religion, traditional medicine and business concerns. Resolution of dilemmas demand the best of the doctor's knowledge of relevant laws and ethics, his training and experience, his religious conviction and moral principles as well as his readiness to benefit from ethics consultation and the advice of his colleagues. Ethics education should begin from the impressionable age in homes, continued in the medical schools and after graduation to ensure that doctors develop good ethical practices and acquire the ability to effectively handle ethical dilemmas. Also, education of patients and sanction of unethical behaviour will reduce ethical dilemmas.

  2. School Administrators Who Serve in Different Institutions Ethical Dilemmas and Their Attitudes towards These Dilemmas

    ERIC Educational Resources Information Center

    Karayama, Saffet

    2018-01-01

    The aim of the study was to determine what ethical dilemmas are faced by school administrators working in different institutions, what they are doing to solve the dilemmas/according to the motives. The research is a patterned qualitative case study and multiple case design is used. 50 school administrators participated by easy-to-reach state…

  3. Bacterial growth rates are influenced by cellular characteristics of individual species when immersed in electromagnetic fields.

    PubMed

    Tessaro, Lucas W E; Murugan, Nirosha J; Persinger, Michael A

    2015-03-01

    Previous studies have shown that exposure to extremely low-frequency electromagnetic fields (ELF-EMFs) have negative effects on the rate of growth of bacteria. In the present study, two Gram-positive and two Gram-negative species were exposed to six magnetic field conditions in broth cultures. Three variations of the 'Thomas' pulsed frequency-modulated pattern; a strong-static "puck" magnet upwards of 5000G in intensity; a pair of these magnets rotating opposite one another at ∼30rpm; and finally a strong dynamic magnetic field generator termed the 'Resonator' with an average intensity of 250μT were used. Growth rate was discerned by optical density (OD) measurements every hour at 600nm. ELF-EMF conditions significantly affected the rates of growth of the bacterial cultures, while the two static magnetic field conditions were not statistically significant. Most interestingly, the 'Resonator' dynamic magnetic field increased the rates of growth of three species (Staphylococcus epidermidis, Staphylococcus aureus, and Escherichia coli), while slowing the growth of one (Serratia marcescens). We suggest that these effects are due to individual biophysical characteristics of the bacterial species. Copyright © 2015 Elsevier GmbH. All rights reserved.

  4. Reframing Educational Leadership in the Perspective of Dilemma.

    ERIC Educational Resources Information Center

    Moller, Jorunn

    This paper describes the dilemmas of leadership experienced by principals and superintendents in Norway. The term "dilemma" refers to contradictory orientations that these educational leaders experienced in their job activities. Dilemmas are categorized in terms of legality, which pertains to the formal steering of the schools, or in…

  5. Investigation of bacterial resistance to the immune system response: cepacian depolymerisation by reactive oxygen species.

    PubMed

    Cuzzi, Bruno; Cescutti, Paola; Furlanis, Linda; Lagatolla, Cristina; Sturiale, Luisa; Garozzo, Domenico; Rizzo, Roberto

    2012-08-01

    Reactive oxygen species (ROS) are part of the weapons used by the immune system to kill and degrade infecting microorganisms. Bacteria can produce macromolecules, such as polysaccharides, that are able to scavenge ROS. Species belonging to the Burkholderia cepacia complex are involved in serious lung infection in cystic fibrosis patients and produce a characteristic polysaccharide, cepacian. The interaction between ROS and bacterial polysaccharides was first investigated by killing experiments, where bacteria cells were incubated with sodium hypochlorite (NaClO) with and without prior incubation with cepacian. The results showed that the polysaccharide had a protective effect towards bacterial cells. Cepacian was then treated with different concentrations of NaClO and the course of reactions was followed by means of capillary viscometry. The degradation products were characterised by size-exclusion chromatography, NMR and mass spectrometry. The results showed that hypochlorite depolymerised cepacian, removed side chains and O-acetyl groups, but did not cleave the glycosidic bond between glucuronic acid and rhamnose. The structure of some oligomers produced by NaClO oxidation is reported.

  6. A Cross-Sectional Survey of Bacterial Species in Plaque from Client Owned Dogs with Healthy Gingiva, Gingivitis or Mild Periodontitis

    PubMed Central

    Davis, Ian J.; Wallis, Corrin; Deusch, Oliver; Colyer, Alison; Milella, Lisa; Loman, Nick; Harris, Stephen

    2013-01-01

    Periodontal disease is the most widespread oral disease in dogs which if left untreated results in significant pain to the pet and loss of dentition. The objective of this study was to identify bacterial species in canine plaque that are significantly associated with health, gingivitis and mild periodontitis (<25% attachment loss). In this survey subgingival plaque samples were collected from 223 dogs with healthy gingiva, gingivitis and mild periodontitis with 72 to 77 samples per health status. DNA was extracted from the plaque samples and subjected to PCR amplification of the V1-V3 region of the 16S rDNA. Pyrosequencing of the PCR amplicons identified a total of 274 operational taxonomic units after bioinformatic and statistical analysis. Porphyromonas was the most abundant genus in all disease stages, particularly in health along with Moraxella and Bergeyella. Peptostreptococcus, Actinomyces, and Peptostreptococcaceae were the most abundant genera in mild periodontitis. Logistic regression analysis identified species from each of these genera that were significantly associated with health, gingivitis or mild periodontitis. Principal component analysis showed distinct community profiles in health and disease. The species identified show some similarities with health and periodontal disease in humans but also major differences. In contrast to human, healthy canine plaque was found to be dominated by Gram negative bacterial species whereas Gram positive anaerobic species predominate in disease. The scale of this study surpasses previously published research and enhances our understanding of the bacterial species present in canine subgingival plaque and their associations with health and early periodontal disease. PMID:24349448

  7. A cross-sectional survey of bacterial species in plaque from client owned dogs with healthy gingiva, gingivitis or mild periodontitis.

    PubMed

    Davis, Ian J; Wallis, Corrin; Deusch, Oliver; Colyer, Alison; Milella, Lisa; Loman, Nick; Harris, Stephen

    2013-01-01

    Periodontal disease is the most widespread oral disease in dogs which if left untreated results in significant pain to the pet and loss of dentition. The objective of this study was to identify bacterial species in canine plaque that are significantly associated with health, gingivitis and mild periodontitis (<25% attachment loss). In this survey subgingival plaque samples were collected from 223 dogs with healthy gingiva, gingivitis and mild periodontitis with 72 to 77 samples per health status. DNA was extracted from the plaque samples and subjected to PCR amplification of the V1-V3 region of the 16S rDNA. Pyrosequencing of the PCR amplicons identified a total of 274 operational taxonomic units after bioinformatic and statistical analysis. Porphyromonas was the most abundant genus in all disease stages, particularly in health along with Moraxella and Bergeyella. Peptostreptococcus, Actinomyces, and Peptostreptococcaceae were the most abundant genera in mild periodontitis. Logistic regression analysis identified species from each of these genera that were significantly associated with health, gingivitis or mild periodontitis. Principal component analysis showed distinct community profiles in health and disease. The species identified show some similarities with health and periodontal disease in humans but also major differences. In contrast to human, healthy canine plaque was found to be dominated by Gram negative bacterial species whereas Gram positive anaerobic species predominate in disease. The scale of this study surpasses previously published research and enhances our understanding of the bacterial species present in canine subgingival plaque and their associations with health and early periodontal disease.

  8. Phylogeographic reconstruction of a bacterial species with high levels of lateral gene transfer

    USGS Publications Warehouse

    Pearson, T.; Giffard, P.; Beckstrom-Sternberg, S.; Auerbach, R.; Hornstra, H.; Tuanyok, A.; Price, E.P.; Glass, M.B.; Leadem, B.; Beckstrom-Sternberg, J. S.; Allan, G.J.; Foster, J.T.; Wagner, D.M.; Okinaka, R.T.; Sim, S.H.; Pearson, O.; Wu, Z.; Chang, J.; Kaul, R.; Hoffmaster, A.R.; Brettin, T.S.; Robison, R.A.; Mayo, M.; Gee, J.E.; Tan, P.; Currie, B.J.; Keim, P.

    2009-01-01

    Background: Phylogeographic reconstruction of some bacterial populations is hindered by low diversity coupled with high levels of lateral gene transfer. A comparison of recombination levels and diversity at seven housekeeping genes for eleven bacterial species, most of which are commonly cited as having high levels of lateral gene transfer shows that the relative contributions of homologous recombination versus mutation for Burkholderia pseudomallei is over two times higher than for Streptococcus pneumoniae and is thus the highest value yet reported in bacteria. Despite the potential for homologous recombination to increase diversity, B. pseudomallei exhibits a relative lack of diversity at these loci. In these situations, whole genome genotyping of orthologous shared single nucleotide polymorphism loci, discovered using next generation sequencing technologies, can provide very large data sets capable of estimating core phylogenetic relationships. We compared and searched 43 whole genome sequences of B. pseudomallei and its closest relatives for single nucleotide polymorphisms in orthologous shared regions to use in phylogenetic reconstruction. Results: Bayesian phylogenetic analyses of >14,000 single nucleotide polymorphisms yielded completely resolved trees for these 43 strains with high levels of statistical support. These results enable a better understanding of a separate analysis of population differentiation among >1,700 B. pseudomallei isolates as defined by sequence data from seven housekeeping genes. We analyzed this larger data set for population structure and allele sharing that can be attributed to lateral gene transfer. Our results suggest that despite an almost panmictic population, we can detect two distinct populations of B. pseudomallei that conform to biogeographic patterns found in many plant and animal species. That is, separation along Wallace's Line, a biogeographic boundary between Southeast Asia and Australia. Conclusion: We describe an

  9. Korean indigenous bacterial species with valid names belonging to the phylum Actinobacteria.

    PubMed

    Bae, Kyung Sook; Kim, Mi Sun; Lee, Ji Hee; Kang, Joo Won; Kim, Dae In; Lee, Ji Hee; Seong, Chi Nam

    2016-12-01

    , Gyeonggi, Jeonnam, Daejeon, and Chungnam. A large number of novel actinobacterial species continue to be discovered since the Korean government is encouraging the search for new bacterial species and researchers are endeavoring to find out novel strains from extreme or untapped environments.

  10. Workplace distress and ethical dilemmas in neuroscience nursing.

    PubMed

    Silén, Marit; Tang, Ping Fen; Wadensten, Barbro; Ahlström, Gerd

    2008-08-01

    This study concerns Swedish nurses' experiences of workplace stress and the occurrence of ethical dilemmas in a neurological setting. Qualitative interviews were conducted with 21 nurses. The interview results were subjected to qualitative latent content analysis and sorted into 4 content areas: workplace distress, ethical dilemmas, managing distress and ethical dilemmas, and quality of nursing. Common workplace stressors were high workload and lack of influence. These were perceived to have negative consequences for the quality of nursing. Ethical dilemmas mainly concerned decision making on initiation or withdrawal of treatment, which was experienced as a troublesome situation where conflicts could arise. The nurses managed the distress and ethical dilemmas by accepting and adjusting to the situation and seeking support from colleagues. They also endeavored to gain new strength in their private lives.

  11. Differentiation of some species of Neisseriaceae and other bacterial groups by DNA-DNA hybridization.

    PubMed

    Tønjum, T; Bukholm, G; Bøvre, K

    1989-05-01

    DNA-DNA hybridization using total genomic DNA probes may represent a way of differentiating between miscellaneous bacterial species. This was studied with type and reference strains of 20 species in Moraxella, Kingella, and other selected Gram-negative groups. Both radioactive and biotin labelling were employed. Most of the species examined were easily distinguished, such as Moraxella (Branhamella) catarrhalis, M.(B.) ovis, M. atlantae, M. phenylpyruvica, M. osloensis, Neisseria elongata, N. meningitidis, Kingella kingae, K. indologenes, K. dentrificans, Oligella urethralis, Eikenella corrodens, Cardiobacterium hominis, Haemophilus aphrophilus, Actinobacillus actinomycetemcomitans, Gardnerella vaginalis, and DF-2. This reflected the extent of the genetic distances between them as a basis for identification by hybridization. There was some clustering in the Moraxella group. Especially the closely related Moraxella nonliquefaciens, M. lacunata and M. bovis showed strong hybridization affinities. This leads to potential problems in distinguishing these three species from each other by DNA-DNA hybridization with total genomic probes alone.

  12. Narrative, emotion and action: analysing 'most memorable' professionalism dilemmas.

    PubMed

    Rees, Charlotte E; Monrouxe, Lynn V; McDonald, Laura A

    2013-01-01

    Although previous studies have explored medical learners''most memorable' experiences, these have typically focused on patient deaths or mistakes. Drawing on multiple theoretical perspectives to understand the interplay between narrative, emotion and action, this paper aims to explore the whats and hows of written narratives of most memorable professionalism dilemmas: what types of dilemma are most memorable? When and where do they take place? How do students act? What characteristics relate to these dilemmas? How are dilemmas narrated? A total of 680 students from 29 of 32 UK medical schools provided a written narrative of their most memorable dilemma as part of their responses to an online questionnaire exploring the impact of professionalism dilemmas on moral distress. We employed quantitative thematic and discourse analysis of all narratives using Linguistic Inquiry Word Count software (LIWC) and conducted a narrative analysis of one exemplar. The most common themes across all narratives concerned dilemmas that related to issues of patient care with reference to the actions of health care professionals or students, student abuse, and consent and intimate examination. A total of 41.1% of experiences had occurred over 6 months previously and 80.1% had taken place in hospital settings. Overall, 54.9% of narrators reported having done something in the face of their dilemma, although only 13.2% described taking obvious or direct action. Numerous characteristics were related to most memorable dilemmas (e.g. narratives citing intimate examinations were more likely to take place in surgical settings). A total of 92.6% of narratives included negative emotion talk and numerous significant relationships emerged between types of emotion talk and most memorable dilemmas (e.g. more anger talk in abuse narratives). Our narrative analysis of one exemplar illustrates the richness of emotion talk and more subtle devices to establish emotional tone. Findings extend previous

  13. Distribution of dilemma zone after intelligent transportation system established

    NASA Astrophysics Data System (ADS)

    Deng, Yuanchang; Yang, Huiqin; Wu, Linying

    2017-03-01

    Dilemma zone refers to an area where vehicles can neither clear the intersection during the yellow interval nor stop safely before the stop line. The purpose of this paper is to analyzing the distribution of two types of dilemma zone after intelligent transportation system (ITS) established at Outer Ring Roads signalized intersections in Guangzhou Higher Education Mega Center. To collect field data a drone aircraft was used. When calculating the type II dilemma zone's distribution, we considered the information of drivers' aggressiveness, which was classified by driving speed and type I dilemma zone as well. We also compared the two types dilemma zone's distribution before and after ITS established and analyzed the changes, which was brought by ITS.

  14. Bacterial communities in floral nectar.

    PubMed

    Fridman, Svetlana; Izhaki, Ido; Gerchman, Yoram; Halpern, Malka

    2012-02-01

    Floral nectar is regarded as the most important reward available to animal-pollinated plants to attract pollinators. Despite the vast amount of publications on nectar properties, the role of nectar as a natural bacterial habitat is yet unexplored. To gain a better understanding of bacterial communities inhabiting floral nectar, culture-dependent and -independent (454-pyrosequencing) methods were used. Our findings demonstrate that bacterial communities in nectar are abundant and diverse. Using culture-dependent method we showed that bacterial communities of nectar displayed significant variation among three plant species: Amygdalus communis, Citrus paradisi and Nicotiana glauca. The dominant class in the nectar bacterial communities was Gammaproteobacteria. About half of the isolates were novel species (< 97% similarities of the 16S rRNA gene with known species). Using 454-pyrosequencing we demonstrated that nectar microbial community are distinct for each of the plant species while there are no significant differences between nectar microbial communities within nectars taken from different plants of the same species. Primary selection of the nectar bacteria is unclear; it may be affected by variations in the chemical composition of the nectar in each plant. The role of the rich and diverse nectar microflora in the attraction-repulsion relationships between the plant and its nectar consumers has yet to be explored. © 2011 Society for Applied Microbiology and Blackwell Publishing Ltd.

  15. Spatial and temporal features of the growth of a bacterial species colonizing the zebrafish gut.

    PubMed

    Jemielita, Matthew; Taormina, Michael J; Burns, Adam R; Hampton, Jennifer S; Rolig, Annah S; Guillemin, Karen; Parthasarathy, Raghuveer

    2014-12-16

    The vertebrate intestine is home to microbial ecosystems that play key roles in host development and health. Little is known about the spatial and temporal dynamics of these microbial communities, limiting our understanding of fundamental properties, such as their mechanisms of growth, propagation, and persistence. To address this, we inoculated initially germ-free zebrafish larvae with fluorescently labeled strains of an Aeromonas species, representing an abundant genus in the zebrafish gut. Using light sheet fluorescence microscopy to obtain three-dimensional images spanning the gut, we quantified the entire bacterial load, as founding populations grew from tens to tens of thousands of cells over several hours. The data yield the first ever measurements of the growth kinetics of a microbial species inside a live vertebrate intestine and show dynamics that robustly fit a logistic growth model. Intriguingly, bacteria were nonuniformly distributed throughout the gut, and bacterial aggregates showed considerably higher growth rates than did discrete individuals. The form of aggregate growth indicates intrinsically higher division rates for clustered bacteria, rather than surface-mediated agglomeration onto clusters. Thus, the spatial organization of gut bacteria both relative to the host and to each other impacts overall growth kinetics, suggesting that spatial characterizations will be an important input to predictive models of host-associated microbial community assembly. Our intestines are home to vast numbers of microbes that influence many aspects of health and disease. Though we now know a great deal about the constituents of the gut microbiota, we understand very little about their spatial structure and temporal dynamics in humans or in any animal: how microbial populations establish themselves, grow, fluctuate, and persist. To address this, we made use of a model organism, the zebrafish, and a new optical imaging technique, light sheet fluorescence microscopy

  16. Influence of fluoride on the bacterial composition of a dual-species biofilm composed of Streptococcus mutans and Streptococcus oralis.

    PubMed

    Jung, Ji-Eun; Cai, Jian-Na; Cho, Sung-Dae; Song, Kwang-Yeob; Jeon, Jae-Gyu

    2016-10-01

    Despite the widespread use of fluoride for the prevention of dental caries, few studies have demonstrated the effects of fluoride on the bacterial composition of dental biofilms. This study investigated whether fluoride affects the proportion of Streptococcus mutans and S. oralis in mono- and dual-species biofilm models, via microbiological, biochemical, and confocal fluorescence microscope studies. Fluoride did not affect the bacterial count and bio-volume of S. mutans and S. oralis in mono-species biofilms, except for the 24-h-old S. mutans biofilms. However, fluoride reduced the proportion and bio-volume of S. mutans but did not decrease those of S. oralis during both S. oralis and S. mutans dual-species biofilm formation, which may be related to the decrease in extracellular polysaccharide formation by fluoride. These results suggest that fluoride may prevent the shift in the microbial proportion to cariogenic bacteria in dental biofilms, subsequently inhibiting the cariogenic bacteria dominant biofilm formation.

  17. Comparative analysis of the intestinal bacterial communities in different species of carp by pyrosequencing.

    PubMed

    Li, Tongtong; Long, Meng; Gatesoupe, François-Joël; Zhang, Qianqian; Li, Aihua; Gong, Xiaoning

    2015-01-01

    Gut microbiota is increasingly regarded as an integral component of the host, due to important roles in the modulation of the immune system, the proliferation of the intestinal epithelium and the regulation of the dietary energy intake. Understanding the factors that influence the composition of these microbial communities is essential to health management, and the application to aquatic animals still requires basic investigation. In this study, we compared the bacterial communities harboured in the intestines and in the rearing water of grass carp (Ctenopharyngodon idellus), crucian carp (Carassius cuvieri), and bighead carp (Hypophthalmichthys nobilis), by using 454-pyrosequencing with barcoded primers targeting the V4 to V5 regions of the bacterial 16S rRNA gene. The specimens of the three species were cohabiting in the same pond. Between 6,218 and 10,220 effective sequences were read from each sample, resulting in a total of 110,398 sequences for 13 samples from gut microbiota and pond water. In general, the microbial communities of the three carps were dominated by Fusobacteria, Firmicutes, Proteobacteria and Bacteroidetes, but the abundance of each phylum was significantly different between species. At the genus level, the overwhelming group was Cetobacterium (97.29 ± 0.46 %) in crucian carp, while its abundance averaged c. 40 and 60 % of the sequences read in the other two species. There was higher microbial diversity in the gut of filter-feeding bighead carp than the gut of the two other species, with grazing feeding habits. The composition of intestine microbiota of grass carp and crucian carp shared higher similarity when compared with bighead carp. The principal coordinates analysis (PCoA) with the weighted UniFrac distance and the heatmap analysis suggested that gut microbiota was not a simple reflection of the microbial community in the local habitat but resulted from species-specific selective pressures, possibly dependent on behavioural, immune

  18. Species richness in soil bacterial communities: a proposed approach to overcome sample size bias.

    PubMed

    Youssef, Noha H; Elshahed, Mostafa S

    2008-09-01

    Estimates of species richness based on 16S rRNA gene clone libraries are increasingly utilized to gauge the level of bacterial diversity within various ecosystems. However, previous studies have indicated that regardless of the utilized approach, species richness estimates obtained are dependent on the size of the analyzed clone libraries. We here propose an approach to overcome sample size bias in species richness estimates in complex microbial communities. Parametric (Maximum likelihood-based and rarefaction curve-based) and non-parametric approaches were used to estimate species richness in a library of 13,001 near full-length 16S rRNA clones derived from soil, as well as in multiple subsets of the original library. Species richness estimates obtained increased with the increase in library size. To obtain a sample size-unbiased estimate of species richness, we calculated the theoretical clone library sizes required to encounter the estimated species richness at various clone library sizes, used curve fitting to determine the theoretical clone library size required to encounter the "true" species richness, and subsequently determined the corresponding sample size-unbiased species richness value. Using this approach, sample size-unbiased estimates of 17,230, 15,571, and 33,912 were obtained for the ML-based, rarefaction curve-based, and ACE-1 estimators, respectively, compared to bias-uncorrected values of 15,009, 11,913, and 20,909.

  19. Species differences in unlocking B-side electron transfer in bacterial reaction centers

    DOE PAGES

    Dylla, Nicholas P.; Faries, Kaitlyn M.; Wyllie, Ryan M.; ...

    2016-06-21

    The structure of the bacterial photosynthetic reaction center (RC) reveals symmetry-related electron transfer (ET) pathways, but only one path is used in native RCs. Analogous mutations have been made in two Rhodobacter (R.) species. A glutamic acid at position 133 in the M subunit increases transmembrane charge separation via the naturally inactive (B-side) path through impacts on primary ET in mutant R. sphaeroidesRCs. Prior work showed that the analogous substitution in the R. capsulatusRC also increases B-side activity, but mainly affects secondary ET. Finally, the overall yields of transmembrane ET are similar, but enabled in fundamentally different ways.

  20. Species differences in unlocking B-side electron transfer in bacterial reaction centers

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Dylla, Nicholas P.; Faries, Kaitlyn M.; Wyllie, Ryan M.

    The structure of the bacterial photosynthetic reaction center (RC) reveals symmetry-related electron transfer (ET) pathways, but only one path is used in native RCs. Analogous mutations have been made in two Rhodobacter (R.) species. A glutamic acid at position 133 in the M subunit increases transmembrane charge separation via the naturally inactive (B-side) path through impacts on primary ET in mutant R. sphaeroidesRCs. Prior work showed that the analogous substitution in the R. capsulatusRC also increases B-side activity, but mainly affects secondary ET. Finally, the overall yields of transmembrane ET are similar, but enabled in fundamentally different ways.

  1. Framing Effect in the Trolley Problem and Footbridge Dilemma.

    PubMed

    Cao, Fei; Zhang, Jiaxi; Song, Lei; Wang, Shoupeng; Miao, Danmin; Peng, Jiaxi

    2017-02-01

    The present study investigated the effect of dilemma type, framing, and number of saved lives on moral decision making. A total of 591 undergraduates, with a mean age of 20.56 (SD = 1.37) were randomly assigned to 12 groups on the basis of a grid of two dilemma types (the trolley problem or the footbridge dilemma) by three frames (positive, neutral, or negative frame) by two different numbers of workers (5 or 15 people). The main effects of dilemma type, frame, and number of saved workers were all significant. The interaction of dilemma type and number of saved workers and the interaction of the three independent factors were significant. Results indicated that moral judgment is affected by framing. Specifically, people were more inclined to utilitarianism in the positive or neutral frame and more inclined to intuitionism in the negative frame. Furthermore, this effect can be moderated by dilemma type and number of saved lives. Implications of our results are discussed.

  2. A Model of Human Cooperation in Social Dilemmas

    PubMed Central

    Capraro, Valerio

    2013-01-01

    Social dilemmas are situations in which collective interests are at odds with private interests: pollution, depletion of natural resources, and intergroup conflicts, are at their core social dilemmas. Because of their multidisciplinarity and their importance, social dilemmas have been studied by economists, biologists, psychologists, sociologists, and political scientists. These studies typically explain tendency to cooperation by dividing people in proself and prosocial types, or appealing to forms of external control or, in iterated social dilemmas, to long-term strategies. But recent experiments have shown that cooperation is possible even in one-shot social dilemmas without forms of external control and the rate of cooperation typically depends on the payoffs. This makes impossible a predictive division between proself and prosocial people and proves that people have attitude to cooperation by nature. The key innovation of this article is in fact to postulate that humans have attitude to cooperation by nature and consequently they do not act a priori as single agents, as assumed by standard economic models, but they forecast how a social dilemma would evolve if they formed coalitions and then they act according to their most optimistic forecast. Formalizing this idea we propose the first predictive model of human cooperation able to organize a number of different experimental findings that are not explained by the standard model. We show also that the model makes satisfactorily accurate quantitative predictions of population average behavior in one-shot social dilemmas. PMID:24009679

  3. Social Values, Subjective Transformations, and Cooperation in Social Dilemmas

    ERIC Educational Resources Information Center

    Simpson, Brent

    2004-01-01

    A persistent anomaly in the social dilemmas literature is the surprisingly high level of cooperation observed in experimental investigations of the one-shot Prisoners' Dilemma (PD). The exchange heuristic hypothesis and related approaches explain this finding by arguing that actors subjectively transform PD into the Assurance Dilemma. A tendency…

  4. Novice Teachers' Case Dilemmas: Surprising Perspectives Related to Diversity.

    ERIC Educational Resources Information Center

    Mastrilli, Thomas; Sardo-Brown, Deborah; Hinson, Stephanie

    This study described novice teachers' case dilemmas, analyzing them for assumptions made by teachers about teaching and learning as well as for solutions to the dilemmas. Twenty-one of the thirty-six dilemmas emphasized either minority students, students of low socioeconomic status, or students from single-parent households. Among the issues…

  5. Ethical Dilemmas in Teaching and Nursing: The Israeli Case

    ERIC Educational Resources Information Center

    Shapira-Lishchinsky, Orly

    2010-01-01

    This article explores a cross-occupational approach for dealing with ethical dilemmas by comparing teaching and nursing. Findings indicate more shared patterns of ethical dilemmas (such as caring for needs for others versus following formal codes) than dilemmas specific to teaching (e.g., advancing universal values versus advancing knowledge) or…

  6. Dilemmas in Bioethics. [Student's Guide.] Preparing for Tomorrow's World.

    ERIC Educational Resources Information Center

    Iozzi, Louis A.; And Others

    The purpose of this module is to introduce students (grades 10-11) to critical bioethical issues by considering moral dilemmas and knowledge of biomedical advances. The module is organized into 12 topic areas, each containing a dilemma story, introductory reading material, sample student responses, and questions. Dilemmas are essentially brief…

  7. Impact of Cropping Systems, Soil Inoculum, and Plant Species Identity on Soil Bacterial Community Structure.

    PubMed

    Ishaq, Suzanne L; Johnson, Stephen P; Miller, Zach J; Lehnhoff, Erik A; Olivo, Sarah; Yeoman, Carl J; Menalled, Fabian D

    2017-02-01

    Farming practices affect the soil microbial community, which in turn impacts crop growth and crop-weed interactions. This study assessed the modification of soil bacterial community structure by organic or conventional cropping systems, weed species identity [Amaranthus retroflexus L. (redroot pigweed) or Avena fatua L. (wild oat)], and living or sterilized inoculum. Soil from eight paired USDA-certified organic and conventional farms in north-central Montana was used as living or autoclave-sterilized inoculant into steam-pasteurized potting soil, planted with Am. retroflexus or Av. fatua and grown for two consecutive 8-week periods to condition soil nutrients and biota. Subsequently, the V3-V4 regions of the microbial 16S rRNA gene were sequenced by Illumina MiSeq. Treatments clustered significantly, with living or sterilized inoculum being the strongest delineating factor, followed by organic or conventional cropping system, then individual farm. Living inoculum-treated soil had greater species richness and was more diverse than sterile inoculum-treated soil (observed OTUs, Chao, inverse Simpson, Shannon, P < 0.001) and had more discriminant taxa delineating groups (linear discriminant analysis). Living inoculum soil contained more Chloroflexi and Acidobacteria, while the sterile inoculum soil had more Bacteroidetes, Firmicutes, Gemmatimonadetes, and Verrucomicrobia. Organically farmed inoculum-treated soil had greater species richness, more diversity (observed OTUs, Chao, Shannon, P < 0.05), and more discriminant taxa than conventionally farmed inoculum-treated soil. Cyanobacteria were higher in pots growing Am. retroflexus, regardless of inoculum type, for three of the four organic farms. Results highlight the potential of cropping systems and species identity to modify soil bacterial communities, subsequently modifying plant growth and crop-weed competition.

  8. Influence of hyaluronic acid on bacterial and fungal species, including clinically relevant opportunistic pathogens.

    PubMed

    Ardizzoni, Andrea; Neglia, Rachele G; Baschieri, Maria C; Cermelli, Claudio; Caratozzolo, Manuela; Righi, Elena; Palmieri, Beniamino; Blasi, Elisabetta

    2011-10-01

    Hyaluronic acid (HA) has several clinical applications (aesthetic surgery, dermatology, orthopaedics and ophtalmology). Following recent evidence, suggesting antimicrobial and antiviral properties for HA, we investigated its effects on 15 ATCC strains, representative of clinically relevant bacterial and fungal species. The in vitro system employed allowed to assess optical density of broth cultures as a measure of microbial load in a time-dependent manner. The results showed that different microbial species and, sometimes, different strains belonging to the same species, are differently affected by HA. In particular, staphylococci, enterococci, Streptococcus mutans, two Escherichia coli strains, Pseudomonas aeruginosa, Candida glabrata and C. parapsilosis displayed a HA dose-dependent growth inhibition; no HA effects were detected in E. coli ATCC 13768 and C. albicans; S. sanguinis was favoured by the highest HA dose. Therefore, the influence of HA on bacteria and fungi warrants further studies aimed at better establishing its relevance in clinical applications.

  9. Impact of cultivation on characterisation of species composition of soil bacterial communities.

    PubMed

    McCaig, A E.; Grayston, S J.; Prosser, J I.; Glover, L A.

    2001-03-01

    The species composition of culturable bacteria in Scottish grassland soils was investigated using a combination of Biolog and 16S rDNA analysis for characterisation of isolates. The inclusion of a molecular approach allowed direct comparison of sequences from culturable bacteria with sequences obtained during analysis of DNA extracted directly from the same soil samples. Bacterial strains were isolated on Pseudomonas isolation agar (PIA), a selective medium, and on tryptone soya agar (TSA), a general laboratory medium. In total, 12 and 21 morphologically different bacterial cultures were isolated on PIA and TSA, respectively. Biolog and sequencing placed PIA isolates in the same taxonomic groups, the majority of cultures belonging to the Pseudomonas (sensu stricto) group. However, analysis of 16S rDNA sequences proved more efficient than Biolog for characterising TSA isolates due to limitations of the Microlog database for identifying environmental bacteria. In general, 16S rDNA sequences from TSA isolates showed high similarities to cultured species represented in sequence databases, although TSA-8 showed only 92.5% similarity to the nearest relative, Bacillus insolitus. In general, there was very little overlap between the culturable and uncultured bacterial communities, although two sequences, PIA-2 and TSA-13, showed >99% similarity to soil clones. A cloning step was included prior to sequence analysis of two isolates, TSA-5 and TSA-14, and analysis of several clones confirmed that these cultures comprised at least four and three sequence types, respectively. All isolate clones were most closely related to uncultured bacteria, with clone TSA-5.1 showing 99.8% similarity to a sequence amplified directly from the same soil sample. Interestingly, one clone, TSA-5.4, clustered within a novel group comprising only uncultured sequences. This group, which is associated with the novel, deep-branching Acidobacterium capsulatum lineage, also included clones isolated

  10. Genomic and phenotypic characterization of Xanthomonas cynarae sp. nov., a new species that causes bacterial bract spot of artichoke (Cynara scolymus L.).

    PubMed

    Trébaol, G; Gardan, L; Manceau, C; Tanguy, J L; Tirilly, Y; Boury, S

    2000-07-01

    A bacterial disease of artichoke (Cynara scolymus L.) was first observed in 1954 in Brittany and the Loire Valley, France. This disease causes water-soaked spots on bracts and depreciates marketability of the harvest. Ten strains of the pathogen causing bacterial spot of artichoke, previously identified as a member of the genus Xanthomonas, were characterized and compared with type and pathotype strains of the 20 Xanthomonas species using a polyphasic study including both phenotypic and genomic methods. The ten strains presented general morphological, biochemical and physiological traits and G+C content characteristic of the genus Xanthomonas. Sequencing of the 165 rRNA gene confirmed that this bacterium belongs to the genus Xanthomonas, and more precisely to the Xanthomonas campestris core. DNA-DNA hybridization results showed that the strains that cause bacterial spot of artichoke were 92-100% related to the proposed type strain CFBP 4188T and constituted a discrete DNA homology group that was distinct from the 20 previously described Xanthomonas species. The results of numerical analysis were in accordance with DNA-DNA hybridization data. Strains causing the bacterial bract spot of artichoke exhibited consistent determinative biochemical characteristics, which distinguished them from the 20 other Xanthomonas species previously described. Furthermore, pathogenicity tests allowed specific identification of this new phytopathogenic bacterium. Thus, it is concluded that this bacterium is a new species belonging to the genus Xanthomonas, for which the name Xanthomonas cynarae is proposed. The type strain, CFBP 4188T, has been deposited in the Collection Française des Bactéries Phytopathogènes (CFBP).

  11. Funding Drives Service Decisions: A Moral Dilemma.

    ERIC Educational Resources Information Center

    Huebner, K. M.; Luxton, L.

    1990-01-01

    The 1990 Josephine L. Taylor Leadership Institute addressed the theme "Funding Drives Service Decisions: A Moral Dilemma." Institute participants identified specific dilemmas related to legislation, funding, and placement issues in education and rehabilitation of visually handicapped individuals. Participants subsequently generated solutions in…

  12. Bacterial community dynamics in a cooling tower with emphasis on pathogenic bacteria and Legionella species using universal and genus-specific deep sequencing.

    PubMed

    Pereira, Rui P A; Peplies, Jörg; Höfle, Manfred G; Brettar, Ingrid

    2017-10-01

    Cooling towers are the major source of outbreaks of legionellosis in Europe and worldwide. These outbreaks are mostly associated with Legionella species, primarily L. pneumophila, and its surveillance in cooling tower environments is of high relevance to public health. In this study, a combined NGS-based approach was used to study the whole bacterial community, specific waterborne and water-based bacterial pathogens, especially Legionella species, targeting the 16S rRNA gene. This approach was applied to water from a cooling tower obtained by monthly sampling during two years. The studied cooling tower was an open circuit cooling tower with lamellar cooling situated in Braunschweig, Germany. A highly diverse bacterial community was observed with 808 genera including 25 potentially pathogenic taxa using universal 16S rRNA primers. Sphingomonas and Legionella were the most abundant pathogenic genera. By applying genus-specific primers for Legionella, a diverse community with 85 phylotypes, and a representative core community with substantial temporal heterogeneity was observed. A high percentage of sequences (65%) could not be affiliated to an acknowledged species. L. pneumophila was part of the core community and the most abundant Legionella species reinforcing the importance of cooling towers as its environmental reservoir. Major temperature shifts (>10 °C) were the key environmental factor triggering the reduction or dominance of the Legionella species in the Legionella community dynamics. In addition, interventions by chlorine dioxide had a strong impact on the Legionella community composition but not on the whole bacterial community. Overall, the presented results demonstrated the value of a combined NGS approach for the molecular monitoring and surveillance of health related pathogens in man-made freshwater systems. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. THE OCCURRENCE OF POLYGLYCEROPHOSPHATE AS AN ANTIGENIC COMPONENT OF VARIOUS GRAM-POSITIVE BACTERIAL SPECIES

    PubMed Central

    McCarty, Maclyn

    1959-01-01

    A bacterial substance has been described which gives a precipitin reaction with certain antisera to Group A streptococci. The precipitating antigen is present in various Gram-positive bacteria, including most hemolytic streptococci, staphylococci, and aerobic sporulating bacilli. It is not present in any of the Gram-negative species examined or in pneumococci, clostridia, or corynebacteria. Analysis of purified preparations obtained from Group A streptococci indicates that the antigen is a simple polymer of glycerophosphate. The identification has been confirmed by immunochemical studies, including precipitin tests and specific inhibition with synthetic polyglycerophosphates. In addition, the infrared spectra of bacterial and synthetic polyglycerophosphate are shown to be closely similar. Immunochemical analysis suggests that the amount of polyglycerophosphate present in Group A streptococci and staphylococci is approximately 1 per cent of the dry weight of the cells. The cellular localization and function of the polyglycerophosphate have not been established. PMID:13641562

  14. Abundance of antibiotic resistance genes and bacterial community composition in wild freshwater fish species.

    PubMed

    Marti, Elisabet; Huerta, Belinda; Rodríguez-Mozaz, Sara; Barceló, Damià; Marcé, Rafael; Balcázar, Jose Luis

    2018-04-01

    This study was aimed to determine the abundance of four antibiotic resistance genes (bla TEM , ermB, qnrS and sulI), as well as bacterial community composition associated with the intestinal mucus of wild freshwater fish species collected from the Foix and La Llosa del Cavall reservoirs, which represent ecosystems with high and low anthropogenic disturbance, respectively. Water and sediments from these reservoirs were also collected and analyzed to determine the pollution level by antibiotics. The bla TEM gene was only detected in brown trout and Ebro barbel, which were collected from La Llosa del Cavall reservoir. In contrast, the sulI and qnrS genes were only detected in common carp, which were collected from the Foix reservoir. Although the ermB gene was also detected in common carp, the values were below the limit of quantification. Likewise, water and sediment samples from the Foix reservoir had higher concentrations and more classes of antibiotics than those from La Llosa del Cavall. Pyrosequencing analysis of 16S rRNA genes revealed significant differences in bacterial communities associated with the intestinal mucus of fish species. Therefore, these findings suggest that anthropogenic activities are not only increasing the pollution of aquatic environments, but also contributing to the emergence and spread of antibiotic resistance in organisms that inhabit such environments. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Goniothalamus Species: A Source of Drugs for the Treatment of Cancers and Bacterial Infections?

    PubMed Central

    2007-01-01

    Irrespective of the presence of cytotoxic acetogenins and styryl-lactones in the genus Goniothalamus, only 22 species in the genus Goniothalamus, out of 160 species (13.7%) have so far been investigated. In an effort to promote further research on the genus Goniothalamus which could represent a source of drugs for the treatment of cancers and bacterial infections, this work offers a broad analysis of current knowledge on Goniothalamus species. Therefore, it includes (i) taxonomy (ii) botanical description (iii) traditional medicinal uses and (iv) phytochemical and pharmacological studies. We discuss the molecular mechanisms of actions of acetogenins and styryl-lactones, with some emphasis on the possible involvement of protein kinase, Bax and TRAIL receptors in the cytotoxic effects of styryl-lactones. We also report (v) the growth inhibition of several nosocomial bacteria by Goniothalamus. scortechinii. The crude methanol extract of G. scortechinii showed a good and broad spectrum of antibacterial activity against both Gram-negative and Gram-positive bacteria. PMID:17965760

  16. Ethical dilemmas in veterinary medicine.

    PubMed

    Morgan, Carol A; McDonald, Michael

    2007-01-01

    Veterinarians frequently encounter situations that are morally charged and potentially difficult to manage. Situation involving euthanasia, end-of-life care, economics, and inadequate provision of care create practical and moral dilemmas. Ethical tension may be attributable to differences in beliefs regarding the moral value of animals, client and veterinary responsibilities, and deciding what is best for an animal. Veterinarians can employ communication skills used in medical situations to explore the reasons underpinning ethical dilemmas and to search for solutions with clients, staff, and colleagues.

  17. Ethical dilemma and moral distress: proposed new NANDA diagnoses.

    PubMed

    Kopala, Beverly; Burkhart, Lisa

    2005-01-01

    To propose two NANDA diagnoses--ethical dilemma and moral distress--and to distinguish between the NANDA diagnosis decisional conflict and the proposed nursing diagnosis of ethical dilemma. Journal articles, books, and focus group research findings. Moral/ethical situations exist in health care. Nurses' experiences of ethical dilemmas and moral distress are extrapolated to the types and categories of ethical dilemmas and moral distress that patients experience and are used as the basis for development of two new nursing diagnoses. The two proposed NANDA diagnoses fill a void in current standardized terminology. It is important that nurses have the ability to diagnose ethical or moral situations in health care. Currently, NANDA does not offer a means to document this important phenomenon. The creation of two sets of nursing diagnoses, ethical dilemma and moral distress, will enable nurses to recognize and track nursing care related to ethical or moral situations.

  18. Memory does not necessarily promote cooperation in dilemma games

    NASA Astrophysics Data System (ADS)

    Wang, Tao; Chen, Zhigang; Li, Kenli; Deng, Xiaoheng; Li, Deng

    2014-02-01

    Evolutionary games can model dilemmas for which cooperation can exist in rational populations. According to intuition, memory of the history can help individuals to overcome the dilemma and increase cooperation. However, here we show that no such general predictions can be made for dilemma games with memory. Agents play repeated prisoner’s dilemma, snowdrift, or stag hunt games in well-mixed populations or on a lattice. We compare the cooperation ratio and fitness for systems with or without memory. An interesting result is that cooperation is demoted in snowdrift and stag hunt games with memory when cost-to-benefit ratio is low, while system fitness still increases with memory in the snowdrift game. To illustrate this interesting phenomenon, two further experiments were performed to study R, ST, and P reciprocity and investigate 16 agent strategies for one-step memory. The results show that memory plays different roles in different dilemma games.

  19. Cooperation Dilemma in Finite Populations under Fluctuating Environments

    NASA Astrophysics Data System (ADS)

    Assaf, Michael; Mobilia, Mauro; Roberts, Elijah

    2013-12-01

    We present a novel approach allowing the study of rare events like fixation under fluctuating environments, modeled as extrinsic noise, in evolutionary processes characterized by the dominance of one species. Our treatment consists of mapping the system onto an auxiliary model, exhibiting metastable species coexistence, that can be analyzed semiclassically. This approach enables us to study the interplay between extrinsic and demographic noise on the statistics of interest. We illustrate our theory by considering the paradigmatic prisoner’s dilemma game, whose evolution is described by the probability that cooperators fixate the population and replace all defectors. We analytically and numerically demonstrate that extrinsic noise may drastically enhance the cooperation fixation probability and even change its functional dependence on the population size. These results, which generalize earlier works in population genetics, indicate that extrinsic noise may help sustain and promote a much higher level of cooperation than static settings.

  20. A Note on Helga's Dilemma: The Dark Side of Kohlberg.

    ERIC Educational Resources Information Center

    Kirman, Joseph M.

    1991-01-01

    Argues that exposing children to some of Lawrence Kohlberg's moral dilemmas, such as Helga's dilemma, may be pedagogically unsound at the elementary-school level. States sample responses provided are inappropriate, rigid, and self-righteous. Provides 10 reasons why this dilemma and its designated responses are of questionable morality. Claims…

  1. Bacterial species involved in the conversion of dietary flavonoids in the human gut.

    PubMed

    Braune, Annett; Blaut, Michael

    2016-05-03

    The gut microbiota plays a crucial role in the conversion of dietary flavonoids and thereby affects their health-promoting effects in the human host. The identification of the bacteria involved in intestinal flavonoid conversion has gained increasing interest. This review summarizes available information on the so far identified human intestinal flavonoid-converting bacterial species and strains as well as their enzymes catalyzing the underlying reactions. The majority of described species involved in flavonoid transformation are capable of carrying out the O-deglycosylation of flavonoids. Other bacteria cleave the less common flavonoid-C-glucosides and/or further degrade the aglycones of flavonols, flavanonols, flavones, flavanones, dihydrochalcones, isoflavones and monomeric flavan-3-ols. To increase the currently limited knowledge in this field, identification of flavonoid-converting bacteria should be continued using culture-dependent screening or isolation procedures and molecular approaches based on sequence information of the involved enzymes.

  2. Themes and Variations: Regulation of RpoN-Dependent Flagellar Genes across Diverse Bacterial Species

    PubMed Central

    Tsang, Jennifer; Hoover, Timothy R.

    2014-01-01

    Flagellar biogenesis in bacteria is a complex process in which the transcription of dozens of structural and regulatory genes is coordinated with the assembly of the flagellum. Although the overall process of flagellar biogenesis is conserved among bacteria, the mechanisms used to regulate flagellar gene expression vary greatly among different bacterial species. Many bacteria use the alternative sigma factor σ 54 (also known as RpoN) to transcribe specific sets of flagellar genes. These bacteria include members of the Epsilonproteobacteria (e.g., Helicobacter pylori and Campylobacter jejuni), Gammaproteobacteria (e.g., Vibrio and Pseudomonas species), and Alphaproteobacteria (e.g., Caulobacter crescentus). This review characterizes the flagellar transcriptional hierarchies in these bacteria and examines what is known about how flagellar gene regulation is linked with other processes including growth phase, quorum sensing, and host colonization. PMID:24672734

  3. Raw Cow Milk Bacterial Population Shifts Attributable to Refrigeration

    PubMed Central

    Lafarge, Véronique; Ogier, Jean-Claude; Girard, Victoria; Maladen, Véronique; Leveau, Jean-Yves; Gruss, Alexandra; Delacroix-Buchet, Agnès

    2004-01-01

    We monitored the dynamic changes in the bacterial population in milk associated with refrigeration. Direct analyses of DNA by using temporal temperature gel electrophoresis (TTGE) and denaturing gradient gel electrophoresis (DGGE) allowed us to make accurate species assignments for bacteria with low-GC-content (low-GC%) (<55%) and medium- or high-GC% (>55%) genomes, respectively. We examined raw milk samples before and after 24-h conservation at 4°C. Bacterial identification was facilitated by comparison with an extensive bacterial reference database (∼150 species) that we established with DNA fragments of pure bacterial strains. Cloning and sequencing of fragments missing from the database were used to achieve complete species identification. Considerable evolution of bacterial populations occurred during conservation at 4°C. TTGE and DGGE are shown to be a powerful tool for identifying the main bacterial species of the raw milk samples and for monitoring changes in bacterial populations during conservation at 4°C. The emergence of psychrotrophic bacteria such as Listeria spp. or Aeromonas hydrophila is demonstrated. PMID:15345453

  4. Dietary and developmental shifts in butterfly-associated bacterial communities

    PubMed Central

    2018-01-01

    Bacterial communities associated with insects can substantially influence host ecology, evolution and behaviour. Host diet is a key factor that shapes bacterial communities, but the impact of dietary transitions across insect development is poorly understood. We analysed bacterial communities of 12 butterfly species across different developmental stages, using amplicon sequencing of the 16S rRNA gene. Butterfly larvae typically consume leaves of a single host plant, whereas adults are more generalist nectar feeders. Thus, we expected bacterial communities to vary substantially across butterfly development. Surprisingly, only few species showed significant dietary and developmental transitions in bacterial communities, suggesting weak impacts of dietary transitions across butterfly development. On the other hand, bacterial communities were strongly influenced by butterfly species and family identity, potentially due to dietary and physiological variation across the host phylogeny. Larvae of most butterfly species largely mirrored bacterial community composition of their diets, suggesting passive acquisition rather than active selection. Overall, our results suggest that although butterflies harbour distinct microbiomes across taxonomic groups and dietary guilds, the dramatic dietary shifts that occur during development do not impose strong selection to maintain distinct bacterial communities across all butterfly hosts. PMID:29892359

  5. How Large Is the Role of Emotion in Judgments of Moral Dilemmas?

    PubMed

    Horne, Zachary; Powell, Derek

    2016-01-01

    Moral dilemmas often pose dramatic and gut-wrenching emotional choices. It is now widely accepted that emotions are not simply experienced alongside people's judgments about moral dilemmas, but that our affective processes play a central role in determining those judgments. However, much of the evidence purporting to demonstrate the connection between people's emotional responses and their judgments about moral dilemmas has recently been called into question. In the present studies, we reexamined the role of emotion in people's judgments about moral dilemmas using a validated self-report measure of emotion. We measured participants' specific emotional responses to moral dilemmas and, although we found that moral dilemmas evoked strong emotional responses, we found that these responses were only weakly correlated with participants' moral judgments. We argue that the purportedly strong connection between emotion and judgments of moral dilemmas may have been overestimated.

  6. Oligotyping reveals differences between gut microbiomes of free-ranging sympatric Namibian carnivores (Acinonyx jubatus, Canis mesomelas) on a bacterial species-like level

    PubMed Central

    Menke, Sebastian; Wasimuddin; Meier, Matthias; Melzheimer, Jörg; Mfune, John K. E.; Heinrich, Sonja; Thalwitzer, Susanne; Wachter, Bettina; Sommer, Simone

    2014-01-01

    Recent gut microbiome studies in model organisms emphasize the effects of intrinsic and extrinsic factors on the variation of the bacterial composition and its impact on the overall health status of the host. Species occurring in the same habitat might share a similar microbiome, especially if they overlap in ecological and behavioral traits. So far, the natural variation in microbiomes of free-ranging wildlife species has not been thoroughly investigated. The few existing studies exploring microbiomes through 16S rRNA gene reads clustered sequencing reads into operational taxonomic units (OTUs) based on a similarity threshold (e.g., 97%). This approach, in combination with the low resolution of target databases, generally limits the level of taxonomic assignments to the genus level. However, distinguishing natural variation of microbiomes in healthy individuals from “abnormal” microbial compositions that affect host health requires knowledge of the “normal” microbial flora at a high taxonomic resolution. This gap can now be addressed using the recently published oligotyping approach, which can resolve closely related organisms into distinct oligotypes by utilizing subtle nucleotide variation. Here, we used Illumina MiSeq to sequence amplicons generated from the V4 region of the 16S rRNA gene to investigate the gut microbiome of two free-ranging sympatric Namibian carnivore species, the cheetah (Acinonyx jubatus) and the black-backed jackal (Canis mesomelas). Bacterial phyla with proportions >0.2% were identical for both species and included Firmicutes, Fusobacteria, Bacteroidetes, Proteobacteria and Actinobacteria. At a finer taxonomic resolution, black-backed jackals exhibited 69 bacterial taxa with proportions ≥0.1%, whereas cheetahs had only 42. Finally, oligotyping revealed that shared bacterial taxa consisted of distinct oligotype profiles. Thus, in contrast to 3% OTUs, oligotyping can detect fine-scale taxonomic differences between microbiomes

  7. Isolation of a lead tolerant novel bacterial species, Achromobacter sp. TL-3: assessment of bioflocculant activity.

    PubMed

    Batta, Neha; Subudhi, Sanjukta; Lal, Banwari; Devi, Arundhuti

    2013-11-01

    Lead is one of the four heavy metals that has a profound damaging effects on human health. In the recent past there has been an increasing global concern for development of sustainable bioremediation technologies for detoxification of lead contaminant. Present investigation highlights for lead biosorption by a newly isolated novel bacterial species; Achromobacter sp. TL-3 strain, isolated from activated sludge samples contaminated with heavy metals (collected from oil refinery, Assam, North-East India). For isolation of lead tolerant bacteria, sludge samples were enriched into Luria Broth medium supplemented separately with a range of lead nitrate; 250, 500, 750, 1000, 1250 and 1500 ppm respectively. The bacterial consortium that could tolerate 1500 ppm of lead nitrate was selected further for purification of lead tolerant bacterial isolates. Purified lead tolerant bacterial isolates were then eventually inoculated into production medium supplemented with ethanol and glycerol as carbon and energy source to investigate for bioflocculant production. Bioflocculant production was estimated by monitoring the potential of lead tolerant bacterial isolate to flocculate Kaolin clay in presence of 1% CaCl2. Compared to other isolates, TL-3 isolate demonstrated for maximum bioflocculant activity of 95% and thus was identified based on 16S rRNA gene sequence analysis. TL3 isolate revealed maximum homology (98%) with Achromobacter sp. and thus designated as Achromobacter sp. TL-3. Bioflocculant activity of TL-3 isolate was correlated with the change in pH and growth. Achromobacter sp. TL-3 has significant potential for lead biosorption and can be effectively employed for detoxification of lead contaminated waste effluents/waste waters.

  8. How Large Is the Role of Emotion in Judgments of Moral Dilemmas?

    PubMed Central

    Horne, Zachary; Powell, Derek

    2016-01-01

    Moral dilemmas often pose dramatic and gut-wrenching emotional choices. It is now widely accepted that emotions are not simply experienced alongside people’s judgments about moral dilemmas, but that our affective processes play a central role in determining those judgments. However, much of the evidence purporting to demonstrate the connection between people’s emotional responses and their judgments about moral dilemmas has recently been called into question. In the present studies, we reexamined the role of emotion in people’s judgments about moral dilemmas using a validated self-report measure of emotion. We measured participants’ specific emotional responses to moral dilemmas and, although we found that moral dilemmas evoked strong emotional responses, we found that these responses were only weakly correlated with participants’ moral judgments. We argue that the purportedly strong connection between emotion and judgments of moral dilemmas may have been overestimated. PMID:27385365

  9. School Restructuring and the Dilemmas of Principals' Work.

    ERIC Educational Resources Information Center

    Wildy, Helen; Louden, William

    2000-01-01

    The complexity of principals' work may be characterized according to three dilemmas: accountability, autonomy, and efficiency. Narrative vignettes of 74 Australian principals revealed that principals were fair and inclusive. When faced with restructuring dilemmas, however, they favored strong over shared leadership, efficiency over collaboration,…

  10. Comparative and bioinformatics analyses of pathogenic bacterial secretomes identified by mass spectrometry in Burkholderia species.

    PubMed

    Nguyen, Thao Thi; Chon, Tae-Soo; Kim, Jaehan; Seo, Young-Su; Heo, Muyoung

    2017-07-01

    Secreted proteins (secretomes) play crucial roles during bacterial pathogenesis in both plant and human hosts. The identification and characterization of secretomes in the two plant pathogens Burkholderia glumae BGR1 and B. gladioli BSR3, which cause diseases in rice such as seedling blight, panicle blight, and grain rot, are important steps to not only understand the disease-causing mechanisms but also find remedies for the diseases. Here, we identified two datasets of secretomes in B. glumae BGR1 and B. gladioli BSR3, which consist of 118 and 111 proteins, respectively, using mass spectrometry approach and literature curation. Next, we characterized the functional properties, potential secretion pathways and sequence information properties of secretomes of two plant pathogens in a comparative analysis by various computational approaches. The ratio of potential non-classically secreted proteins (NCSPs) to classically secreted proteins (CSPs) in B. glumae BGR1 was greater than that in B. gladioli BSR3. For CSPs, the putative hydrophobic regions (PHRs) which are essential for secretion process of CSPs were screened in detail at their N-terminal sequences using hidden Markov model (HMM)-based method. Total 31 pairs of homologous proteins in two bacterial secretomes were indicated based on the global alignment (identity ≥ 70%). Our results may facilitate the understanding of the species-specific features of secretomes in two plant pathogenic Burkholderia species.

  11. Bacterial Communities in Women with Bacterial Vaginosis: High Resolution Phylogenetic Analyses Reveal Relationships of Microbiota to Clinical Criteria

    PubMed Central

    Srinivasan, Sujatha; Hoffman, Noah G.; Morgan, Martin T.; Matsen, Frederick A.; Fiedler, Tina L.; Hall, Robert W.; Ross, Frederick J.; McCoy, Connor O.; Bumgarner, Roger; Marrazzo, Jeanne M.; Fredricks, David N.

    2012-01-01

    Background Bacterial vaginosis (BV) is a common condition that is associated with numerous adverse health outcomes and is characterized by poorly understood changes in the vaginal microbiota. We sought to describe the composition and diversity of the vaginal bacterial biota in women with BV using deep sequencing of the 16S rRNA gene coupled with species-level taxonomic identification. We investigated the associations between the presence of individual bacterial species and clinical diagnostic characteristics of BV. Methodology/Principal Findings Broad-range 16S rRNA gene PCR and pyrosequencing were performed on vaginal swabs from 220 women with and without BV. BV was assessed by Amsel’s clinical criteria and confirmed by Gram stain. Taxonomic classification was performed using phylogenetic placement tools that assigned 99% of query sequence reads to the species level. Women with BV had heterogeneous vaginal bacterial communities that were usually not dominated by a single taxon. In the absence of BV, vaginal bacterial communities were dominated by either Lactobacillus crispatus or Lactobacillus iners. Leptotrichia amnionii and Eggerthella sp. were the only two BV-associated bacteria (BVABs) significantly associated with each of the four Amsel’s criteria. Co-occurrence analysis revealed the presence of several sub-groups of BVABs suggesting metabolic co-dependencies. Greater abundance of several BVABs was observed in Black women without BV. Conclusions/Significance The human vaginal bacterial biota is heterogeneous and marked by greater species richness and diversity in women with BV; no species is universally present. Different bacterial species have different associations with the four clinical criteria, which may account for discrepancies often observed between Amsel and Nugent (Gram stain) diagnostic criteria. Several BVABs exhibited race-dependent prevalence when analyzed in separate groups by BV status which may contribute to increased incidence of BV in

  12. Solving Ethical Dilemmas with Children: Empowering Classroom Research

    ERIC Educational Resources Information Center

    Parr, Michelann

    2010-01-01

    This article identifies and discusses ethical dilemmas inherent when undertaking research with children or other vulnerable populations: power relations, risks and benefits, and informed consent and confidentiality (Maguire, 2005). Ethical dilemmas often arise when researchers attempt to merge the interests of their research and the interests of…

  13. Emotional Multiagent Reinforcement Learning in Spatial Social Dilemmas.

    PubMed

    Yu, Chao; Zhang, Minjie; Ren, Fenghui; Tan, Guozhen

    2015-12-01

    Social dilemmas have attracted extensive interest in the research of multiagent systems in order to study the emergence of cooperative behaviors among selfish agents. Understanding how agents can achieve cooperation in social dilemmas through learning from local experience is a critical problem that has motivated researchers for decades. This paper investigates the possibility of exploiting emotions in agent learning in order to facilitate the emergence of cooperation in social dilemmas. In particular, the spatial version of social dilemmas is considered to study the impact of local interactions on the emergence of cooperation in the whole system. A double-layered emotional multiagent reinforcement learning framework is proposed to endow agents with internal cognitive and emotional capabilities that can drive these agents to learn cooperative behaviors. Experimental results reveal that various network topologies and agent heterogeneities have significant impacts on agent learning behaviors in the proposed framework, and under certain circumstances, high levels of cooperation can be achieved among the agents.

  14. Roman Catholic beliefs produce characteristic neural responses to moral dilemmas

    PubMed Central

    Flexas, Albert; de Miguel, Pedro; Cela-Conde, Camilo J.; Munar, Enric

    2014-01-01

    This study provides exploratory evidence about how behavioral and neural responses to standard moral dilemmas are influenced by religious belief. Eleven Catholics and 13 Atheists (all female) judged 48 moral dilemmas. Differential neural activity between the two groups was found in precuneus and in prefrontal, frontal and temporal regions. Furthermore, a double dissociation showed that Catholics recruited different areas for deontological (precuneus; temporoparietal junction) and utilitarian moral judgments [dorsolateral prefrontal cortex (DLPFC); temporal poles], whereas Atheists did not (superior parietal gyrus for both types of judgment). Finally, we tested how both groups responded to personal and impersonal moral dilemmas: Catholics showed enhanced activity in DLPFC and posterior cingulate cortex during utilitarian moral judgments to impersonal moral dilemmas and enhanced responses in anterior cingulate cortex and superior temporal sulcus during deontological moral judgments to personal moral dilemmas. Our results indicate that moral judgment can be influenced by an acquired set of norms and conventions transmitted through religious indoctrination and practice. Catholic individuals may hold enhanced awareness of the incommensurability between two unequivocal doctrines of the Catholic belief set, triggered explicitly in a moral dilemma: help and care in all circumstances—but thou shalt not kill. PMID:23160812

  15. Roman Catholic beliefs produce characteristic neural responses to moral dilemmas.

    PubMed

    Christensen, Julia F; Flexas, Albert; de Miguel, Pedro; Cela-Conde, Camilo J; Munar, Enric

    2014-02-01

    This study provides exploratory evidence about how behavioral and neural responses to standard moral dilemmas are influenced by religious belief. Eleven Catholics and 13 Atheists (all female) judged 48 moral dilemmas. Differential neural activity between the two groups was found in precuneus and in prefrontal, frontal and temporal regions. Furthermore, a double dissociation showed that Catholics recruited different areas for deontological (precuneus; temporoparietal junction) and utilitarian moral judgments [dorsolateral prefrontal cortex (DLPFC); temporal poles], whereas Atheists did not (superior parietal gyrus for both types of judgment). Finally, we tested how both groups responded to personal and impersonal moral dilemmas: Catholics showed enhanced activity in DLPFC and posterior cingulate cortex during utilitarian moral judgments to impersonal moral dilemmas and enhanced responses in anterior cingulate cortex and superior temporal sulcus during deontological moral judgments to personal moral dilemmas. Our results indicate that moral judgment can be influenced by an acquired set of norms and conventions transmitted through religious indoctrination and practice. Catholic individuals may hold enhanced awareness of the incommensurability between two unequivocal doctrines of the Catholic belief set, triggered explicitly in a moral dilemma: help and care in all circumstances-but thou shalt not kill.

  16. An Application of Evolutionary Game Theory to Social Dilemmas: The Traveler's Dilemma and the Minimum Effort Coordination Game

    PubMed Central

    Iyer, Swami; Reyes, Joshua; Killingback, Timothy

    2014-01-01

    The Traveler's Dilemma game and the Minimum Effort Coordination game are two social dilemmas that have attracted considerable attention due to the fact that the predictions of classical game theory are at odds with the results found when the games are studied experimentally. Moreover, a direct application of deterministic evolutionary game theory, as embodied in the replicator dynamics, to these games does not explain the observed behavior. In this work, we formulate natural variants of these two games as smoothed continuous-strategy games. We study the evolutionary dynamics of these continuous-strategy games, both analytically and through agent-based simulations, and show that the behavior predicted theoretically is in accord with that observed experimentally. Thus, these variants of the Traveler's Dilemma and the Minimum Effort Coordination games provide a simple resolution of the paradoxical behavior associated with the original games. PMID:24709851

  17. An application of evolutionary game theory to social dilemmas: the traveler's dilemma and the minimum effort coordination game.

    PubMed

    Iyer, Swami; Reyes, Joshua; Killingback, Timothy

    2014-01-01

    The Traveler's Dilemma game and the Minimum Effort Coordination game are two social dilemmas that have attracted considerable attention due to the fact that the predictions of classical game theory are at odds with the results found when the games are studied experimentally. Moreover, a direct application of deterministic evolutionary game theory, as embodied in the replicator dynamics, to these games does not explain the observed behavior. In this work, we formulate natural variants of these two games as smoothed continuous-strategy games. We study the evolutionary dynamics of these continuous-strategy games, both analytically and through agent-based simulations, and show that the behavior predicted theoretically is in accord with that observed experimentally. Thus, these variants of the Traveler's Dilemma and the Minimum Effort Coordination games provide a simple resolution of the paradoxical behavior associated with the original games.

  18. Bacterial Species and Antibiotic Sensitivity in Korean Patients Diagnosed with Acute Otitis Media and Otitis Media with Effusion.

    PubMed

    Kim, Sang Hoon; Jeon, Eun Ju; Hong, Seok Min; Bae, Chang Hoon; Lee, Ho Yun; Park, Moo Kyun; Byun, Jae Yong; Kim, Myung Gu; Yeo, Seung Geun

    2017-04-01

    Changes over time in pathogens and their antibiotic sensitivity resulting from the recent overuse and misuse of antibiotics in otitis media (OM) have complicated treatment. This study evaluated changes over 5 years in principal pathogens and their antibiotic sensitivity in patients in Korea diagnosed with acute OM (AOM) and OM with effusion (OME). The study population consisted of 683 patients who visited the outpatient department of otorhinolaryngology in 7 tertiary hospitals in Korea between January 2010 and May 2015 and were diagnosed with acute AOM or OME. Aural discharge or middle ear fluid were collected from patients in the operating room or outpatient department and subjected to tests of bacterial identification and antibiotic sensitivity. The overall bacteria detection rate of AOM was 62.3% and OME was 40.9%. The most frequently isolated Gram-positive bacterial species was coagulase negative Staphylococcus aureus (CNS) followed by methicillin-susceptible S. aureus (MSSA), methicillin-resistant S. aureus (MRSA), and Streptococcus pneumonia (SP), whereas the most frequently isolated Gram-negative bacterium was Pseudomonas aeruginosa (PA). Regardless of OM subtype, ≥ 80% of CNS and MRSA strains were resistant to penicillin (PC) and tetracycline (TC); isolated MRSA strains showed low sensitivity to other antibiotics, with 100% resistant to PC, TC, cefoxitin (CFT), and erythromycin (EM); and isolated PA showed low sensitivity to quinolone antibiotics, including ciprofloxacin (CIP) and levofloxacin (LFX), and to aminoglycosides. Bacterial species and antibiotic sensitivity did not change significantly over 5 years. The rate of detection of MRSA was higher in OME than in previous studies. As bacterial predominance and antibiotic sensitivity could change over time, continuous and periodic surveillance is necessary in guiding appropriate antibacterial therapy. © 2017 The Korean Academy of Medical Sciences.

  19. Lactobacillus species isolated from vaginal secretions of healthy and bacterial vaginosis-intermediate Mexican women: a prospective study

    PubMed Central

    2013-01-01

    Background Lactobacillus jensenii, L. iners, L. crispatus and L. gasseri are the most frequently occurring lactobacilli in the vagina. However, the native species vary widely according to the studied population. The present study was performed to genetically determine the identity of Lactobacillus strains present in the vaginal discharge of healthy and bacterial vaginosis (BV) intermediate Mexican women. Methods In a prospective study, 31 strains preliminarily identified as Lactobacillus species were isolated from 21 samples collected from 105 non-pregnant Mexican women. The samples were classified into groups according to the Nugent score criteria proposed for detection of BV: normal (N), intermediate (I) and bacterial vaginosis (BV). We examined the isolates using culture-based methods as well as molecular analysis of the V1–V3 regions of the 16S rRNA gene. Enterobacterial repetitive intergenic consensus (ERIC) sequence analysis was performed to reject clones. Results Clinical isolates (25/31) were classified into four groups based on sequencing and analysis of the 16S rRNA gene: L. acidophilus (14/25), L. reuteri (6/25), L. casei (4/25) and L. buchneri (1/25). The remaining six isolates were presumptively identified as Enterococcus species. Within the L. acidophilus group, L. gasseri was the most frequently isolated species, followed by L. jensenii and L. crispatus. L. fermentum, L. rhamnosus and L. brevis were also isolated, and were placed in the L. reuteri, L. casei and L. buchneri groups, respectively. ERIC profile analysis showed intraspecific variability amongst the L. gasseri and L. fermentum species. Conclusions These findings agree with previous studies showing that L. crispatus, L. gasseri and L. jensenii are consistently present in the healthy vaginal ecosystem. Additional species or phylotypes were detected in the vaginal microbiota of the non-pregnant Mexican (Hispanic-mestizo) population, and thus, these results further our understanding of

  20. Exposure of Bacterial Biofilms to Electrical Current Leads to Cell Death Mediated in Part by Reactive Oxygen Species

    PubMed Central

    Brinkman, Cassandra L.; Schmidt-Malan, Suzannah M.; Karau, Melissa J.; Greenwood-Quaintance, Kerryl; Hassett, Daniel J.; Mandrekar, Jayawant N.

    2016-01-01

    Bacterial biofilms may form on indwelling medical devices such as prosthetic joints, heart valves and catheters, causing challenging-to-treat infections. We have previously described the ‘electricidal effect’, in which bacterial biofilms are decreased following exposure to direct electrical current. Herein, we sought to determine if the decreased bacterial quantities are due to detachment of biofilms or cell death and to investigate the role that reactive oxygen species (ROS) play in the observed effect. Using confocal and electron microscopy and flow cytometry, we found that direct current (DC) leads to cell death and changes in the architecture of biofilms formed by Gram-positive and Gram-negative bacteria. Reactive oxygen species (ROS) appear to play a role in DC-associated cell death, as there was an increase in ROS-production by Staphylococcus aureus and Staphylococcus epidermidis biofilms following exposure to DC. An increase in the production of ROS response enzymes catalase and superoxide dismutase (SOD) was observed for S. aureus, S. epidermidis and Pseudomonas aeruginosa biofilms following exposure to DC. Additionally, biofilms were protected from cell death when supplemented with antioxidants and oxidant scavengers, including catalase, mannitol and Tempol. Knocking out SOD (sodAB) in P. aeruginosa led to an enhanced DC effect. Microarray analysis of P. aeruginosa PAO1 showed transcriptional changes in genes related to the stress response and cell death. In conclusion, the electricidal effect results in death of bacteria in biofilms, mediated, at least in part, by production of ROS. PMID:27992529

  1. Exposure of Bacterial Biofilms to Electrical Current Leads to Cell Death Mediated in Part by Reactive Oxygen Species.

    PubMed

    Brinkman, Cassandra L; Schmidt-Malan, Suzannah M; Karau, Melissa J; Greenwood-Quaintance, Kerryl; Hassett, Daniel J; Mandrekar, Jayawant N; Patel, Robin

    2016-01-01

    Bacterial biofilms may form on indwelling medical devices such as prosthetic joints, heart valves and catheters, causing challenging-to-treat infections. We have previously described the 'electricidal effect', in which bacterial biofilms are decreased following exposure to direct electrical current. Herein, we sought to determine if the decreased bacterial quantities are due to detachment of biofilms or cell death and to investigate the role that reactive oxygen species (ROS) play in the observed effect. Using confocal and electron microscopy and flow cytometry, we found that direct current (DC) leads to cell death and changes in the architecture of biofilms formed by Gram-positive and Gram-negative bacteria. Reactive oxygen species (ROS) appear to play a role in DC-associated cell death, as there was an increase in ROS-production by Staphylococcus aureus and Staphylococcus epidermidis biofilms following exposure to DC. An increase in the production of ROS response enzymes catalase and superoxide dismutase (SOD) was observed for S. aureus, S. epidermidis and Pseudomonas aeruginosa biofilms following exposure to DC. Additionally, biofilms were protected from cell death when supplemented with antioxidants and oxidant scavengers, including catalase, mannitol and Tempol. Knocking out SOD (sodAB) in P. aeruginosa led to an enhanced DC effect. Microarray analysis of P. aeruginosa PAO1 showed transcriptional changes in genes related to the stress response and cell death. In conclusion, the electricidal effect results in death of bacteria in biofilms, mediated, at least in part, by production of ROS.

  2. Nurses' contributions to the resolution of ethical dilemmas in practice.

    PubMed

    Barlow, Nichola Ann; Hargreaves, Janet; Gillibrand, Warren P

    2018-03-01

    Complex and expensive treatment options have increased the frequency and emphasis of ethical decision-making in healthcare. In order to meet these challenges effectively, we need to identify how nurses contribute the resolution of these dilemmas. To identify the values, beliefs and contextual influences that inform decision-making. To identify the contribution made by nurses in achieving the resolution of ethical dilemmas in practice. An interpretive exploratory study was undertaken, 11 registered acute care nurses working in a district general hospital in England were interviewed, using semi-structured interviews. In-depth content analysis of the data was undertaken via NVivo coding and thematic identification. Participants and context: Participants were interviewed about their contribution to the resolution of ethical dilemmas within the context of working in an acute hospital ward. Participants were recruited from all settings working with patients of any age and any diagnosis. Ethical considerations: Ethical approval was obtained from the local National Research Ethics Committee. Four major themes emerged: 'best for the patient', 'accountability', 'collaboration and conflict' and 'concern for others'. Moral distress was also evident in the literature and findings, with moral dissonance recognised and articulated by more experienced nurses. The relatively small, single-site sample may not account for the effects of organisational culture on the results; the findings suggested that professional relationships were key to resolving ethical dilemmas. Nurses use their moral reasoning based on their beliefs and values when faced with ethical dilemmas. Subsequent actions are mediated though ethical decision-making frames of reference including deontology, consequentialism, the ethics of care and virtue ethics. Nurses use these in contributing to the resolution of these dilemmas. Nurses require the skills to develop and maintain professional relationships for addressing

  3. Ethical concerns and dilemmas of Finnish and Dutch health professionals.

    PubMed

    Hopia, Hanna; Lottes, Ilsa; Kanne, Mariël

    2016-09-01

    Healthcare professionals encounter ethical dilemmas and concerns in their practice. More research is needed to understand these ethical problems and to know how to educate professionals to respond to them. To describe ethical dilemmas and concerns at work from the perspectives of Finnish and Dutch healthcare professionals studying at the master's level. Exploratory, qualitative study that used the text of student online discussions of ethical dilemmas at work as data. Participants' online discussions were analyzed using inductive content analysis. The sample consisted of 49 students at master's level enrolled in professional ethics courses at universities in Finland and the Netherlands. Permission for conducting the study was granted from both universities of applied sciences. All students provided their informed consent for the use of their assignments as research data. Participants described 51 problematic work situations. Among these, 16 were found to be ethical dilemmas, and the remaining were work issues with an ethical concern and did not meet criteria of a dilemma. The most common problems resulted from concerns about quality care, safety of healthcare professionals, patients' rights, and working with too few staff and inadequate resources. The results indicated that participants were concerned about providing quality of care and raised numerous questions about how to provide it in challenging situations. The results show that it was difficult for students to differentiate ethical dilemmas from other ethical work concerns. Online discussions among healthcare providers give them an opportunity to relate ethical principles to real ethical dilemmas and problems in their work as well as to critically analyze ethical issues. We found that discussions with descriptions of ethical dilemmas and concerns by health professionals provide important information and recommendations not only for education and practice but also for health policy. © The Author(s) 2015.

  4. The Development of Artistic Style: Transformations of a Creator's Core Dilemma.

    ERIC Educational Resources Information Center

    Cohen-Shalev, Amir

    1993-01-01

    In the works of the playwright Pierre Corneille, the core dilemma of love versus duty, which underlay the artist's endeavors, evolved from the stage of articulation or problem finding in early adulthood, to dilemma resolution at midlife, and finally to dilemma fragmentation in old age. Argues that the dialectical tensions underlying creativity are…

  5. Exploring Ethical Dilemmas Using the "Drifting Goals" Archetype

    ERIC Educational Resources Information Center

    Bardoel, E. Anne; Haslett, Tim

    2006-01-01

    This article demonstrates how the system archetype "drifting goals" can be used in the classroom to explore ethical dilemmas. System archetypes provide a framework that shifts the focus from seeing ethical dilemmas as stemming solely from the acts of individuals to exploring the systemic structures that are responsible for generic patterns of…

  6. Surface-Selective Preferential Production of Reactive Oxygen Species on Piezoelectric Ceramics for Bacterial Killing.

    PubMed

    Tan, Guoxin; Wang, Shuangying; Zhu, Ye; Zhou, Lei; Yu, Peng; Wang, Xiaolan; He, Tianrui; Chen, Junqi; Mao, Chuanbin; Ning, Chengyun

    2016-09-21

    Reactive oxygen species (ROS) can be used to kill bacterial cells, and thus the selective generation of ROS from material surfaces is an emerging direction in antibacterial material discovery. We found the polarization of piezoelectric ceramic causes the two sides of the disk to become positively and negatively charged, which translate into cathode and anode surfaces in an aqueous solution. Because of the microelectrolysis of water, ROS are preferentially formed on the cathode surface. Consequently, the bacteria are selectively killed on the cathode surface. However, the cell experiment suggested that the level of ROS is safe for normal mammalian cells.

  7. Bacterial surface adaptation

    NASA Astrophysics Data System (ADS)

    Utada, Andrew

    2014-03-01

    Biofilms are structured multi-cellular communities that are fundamental to the biology and ecology of bacteria. Parasitic bacterial biofilms can cause lethal infections and biofouling, but commensal bacterial biofilms, such as those found in the gut, can break down otherwise indigestible plant polysaccharides and allow us to enjoy vegetables. The first step in biofilm formation, adaptation to life on a surface, requires a working knowledge of low Reynolds number fluid physics, and the coordination of biochemical signaling, polysaccharide production, and molecular motility motors. These crucial early stages of biofilm formation are at present poorly understood. By adapting methods from soft matter physics, we dissect bacterial social behavior at the single cell level for several prototypical bacterial species, including Pseudomonas aeruginosa and Vibrio cholerae.

  8. Assessing the Effect of Litter Species on the Dynamic of Bacterial and Fungal Communities during Leaf Decomposition in Microcosm by Molecular Techniques

    PubMed Central

    Xu, Wenjing; Shi, Lingling; Chan, Onchim; Li, Jiao; Casper, Peter; Zou, Xiaoming

    2013-01-01

    Although bacteria and fungi are well-known to be decomposers of leaf litter, few studies have examined their compositions and diversities during the decomposition process in tropical stream water. Xishuangbanna is a tropical region preserving one of the highest floristic diversity areas in China. In this study, leaf litter of four dominant plant species in Xishuangbanna was incubated in stream water for 42 days during which samples were taken regularly. Following DNA extraction, PCR-DGGE (denaturing gradient gel electrophoresis) and clone-sequencing analyses were performed using bacterial and fungal specific primers. Leaf species have slightly influences on bacterial community rather than fungal community. The richness and diversity of bacteria was higher than that of fungi, which increased towards the end of the 42-day-incubation. The bacterial community was initially more specific upon the type of leaves and gradually became similar at the later stage of decomposition with alpha-proteobacteria as major component. Sequences affiliated to methanotrophs were obtained that indicates potentially occurrence of methane oxidation and methanogenesis. For the fungal community, sequences affiliated to Aspergillus were predominant at the beginning and then shifted to Pleosporales. Our results suggest that the microorganisms colonizing leaf biofilm in tropical stream water were mostly generalists that could exploit the resources of leaves of various species equally well. PMID:24367682

  9. Comparative Genomic Analyses of the Bacterial Phosphotransferase System

    PubMed Central

    Barabote, Ravi D.; Saier, Milton H.

    2005-01-01

    We report analyses of 202 fully sequenced genomes for homologues of known protein constituents of the bacterial phosphoenolpyruvate-dependent phosphotransferase system (PTS). These included 174 bacterial, 19 archaeal, and 9 eukaryotic genomes. Homologues of PTS proteins were not identified in archaea or eukaryotes, showing that the horizontal transfer of genes encoding PTS proteins has not occurred between the three domains of life. Of the 174 bacterial genomes (136 bacterial species) analyzed, 30 diverse species have no PTS homologues, and 29 species have cytoplasmic PTS phosphoryl transfer protein homologues but lack recognizable PTS permeases. These soluble homologues presumably function in regulation. The remaining 77 species possess all PTS proteins required for the transport and phosphorylation of at least one sugar via the PTS. Up to 3.2% of the genes in a bacterium encode PTS proteins. These homologues were analyzed for family association, range of protein types, domain organization, and organismal distribution. Different strains of a single bacterial species often possess strikingly different complements of PTS proteins. Types of PTS protein domain fusions were analyzed, showing that certain types of domain fusions are common, while others are rare or prohibited. Select PTS proteins were analyzed from different phylogenetic standpoints, showing that PTS protein phylogeny often differs from organismal phylogeny. The results document the frequent gain and loss of PTS protein-encoding genes and suggest that the lateral transfer of these genes within the bacterial domain has played an important role in bacterial evolution. Our studies provide insight into the development of complex multicomponent enzyme systems and lead to predictions regarding the types of protein-protein interactions that promote efficient PTS-mediated phosphoryl transfer. PMID:16339738

  10. Viral-bacterial associations in acute apical abscesses.

    PubMed

    Ferreira, Dennis C; Rôças, Isabela N; Paiva, Simone S M; Carmo, Flávia L; Cavalcante, Fernanda S; Rosado, Alexandre S; Santos, Kátia R N; Siqueira, José F

    2011-08-01

    Viral-bacterial and bacterial synergism have been suggested to contribute to the pathogenesis of several human diseases. This study sought to investigate the possible associations between 9 candidate endodontic bacterial pathogens and 9 human viruses in samples from acute apical abscesses. DNA extracts from purulent exudate aspirates of 33 cases of acute apical abscess were surveyed for the presence of 9 selected bacterial species using a 16S ribosomal RNA gene-based nested polymerase chain reaction (PCR) approach. Single or nested PCR assays were used for detection of the human papillomavirus (HPV) and herpesviruses types 1 to 8. Two-thirds of the abscess samples were positive for at least one of the target viruses. Specifically, the most frequently detected viruses were HHV-8 (54.5%); HPV (9%); and varicella zoster virus (VZV), Epstein-Barr virus (EBV), and HHV-6 (6%). Bacterial DNA was present in all cases and the most prevalent bacterial species were Treponema denticola (70%), Tannerella forsythia (67%), Porphyromonas endodontalis (67%), Dialister invisus (61%), and Dialister pneumosintes (57.5%). HHV-8 was positively associated with 7 of the target bacterial species and HPV with 4, but all these associations were weak. Several bacterial pairs showed a moderate positive association. Viral coinfection was found in 6 abscess cases, but no significant viral association could be determined. Findings demonstrated that bacterial and viral DNA occurred concomitantly in two-thirds of the samples from endodontic abscesses. Although this may suggest a role for viruses in the etiology of apical abscesses, the possibility also exists that the presence of viruses in abscess samples is merely a consequence of the bacterially induced disease process. Further studies are necessary to clarify the role of these viral-bacterial interactions, if any, in the pathogenesis of acute apical abscesses. Copyright © 2011 Mosby, Inc. All rights reserved.

  11. Jeb Stewart's Dilemma

    ERIC Educational Resources Information Center

    Cedo, Kelli M.; Dickerson, William E.

    2010-01-01

    This case study creates a dilemma that many school districts face. Public education is under-funded. Principals are expected to be the instructional leaders and are held accountable for student achievement. Is it appropriate then for public schools to have local businesses as benefactors when teaching personnel are involved? The conflict between…

  12. Bacterial colonization of the phyllosphere of mediterranean perennial species as influenced by leaf structural and chemical features.

    PubMed

    Yadav, R K P; Karamanoli, K; Vokou, D

    2005-08-01

    In this study, we assessed various leaf structural and chemical features as possible predictors of the size of the phyllosphere bacterial population in the Mediterranean environment. We examined eight perennial species, naturally occurring and coexisting in the same area, in Halkidiki (northern Greece). They are Arbutus unedo, Quercus coccifera, Pistacia lentiscus, and Myrtus communis (evergreen sclerophyllous species), Lavandula stoechas and Cistus incanus (drought semi-deciduous species), and Calamintha nepeta and Melissa officinalis (non-woody perennial species). M. communis, L. stoechas, C. nepeta, and M. officinalis produce essential oil in substantial quantities. We sampled summer leaves from these species and (1) estimated the size of the bacterial population of their phyllosphere, (2) estimated the concentration of different leaf constituents, and (3) studied leaf morphological and anatomical features and expressed them in a quantitative way. The aromatic plants are on average more highly colonized than the other species, whereas the non-woody perennials are more highly colonized than the woody species. The population size of epiphytic bacteria is positively correlated with glandular and non-glandular trichome densities, and with water and phosphorus contents; it is negatively correlated with total phenolics content and the thickness of the leaf, of the mesophyll, and of the abaxial epidermis. No correlation was found with the density of stomata, the nitrogen, and the soluble sugar contents. By regression tree analysis, we found that the leaf-microbe system can be effectively described by three leaf attributes with leaf water content being the primary explanatory attribute. Leaves with water content >73% are the most highly colonized. For leaves with water content <73%, the phosphorus content, with a critical value of 1.34 mg g(-1) d.w., is the next explanatory leaf attribute, followed by the thickness of the adaxial epidermis. Leaves higher in phosphorus

  13. Learning Objects and the E-Learning Cost Dilemma

    ERIC Educational Resources Information Center

    Weller, Martin

    2004-01-01

    The creation of quality e-learning material creates a cost dilemma for many institutions, since it has both high variable and high fixed costs. This cost dilemma means that economies of scale are difficult to achieve, which may result in a consequent reduction in the quality of the learning material. Based on the experience of creating a masters…

  14. Clinical ethics consultation's dilemma, and a solution.

    PubMed

    Rasmussen, Lisa M

    2011-01-01

    Clinical ethics consultation is on the horns of a dilemma. One horn skewers the field for its lack of standards, while the other horn skewers it for proposing arbitrary or deeply contested foundations. I articulate the dilemma by discussing several critiques of the field and the challenge of formulating standards and suggest that the solution lies, at least until a robust consensus emerges, with establishing a list of proscriptive standards to guide the field.

  15. Moral Dilemmas and the Concept of Value in Engineering Ethics

    NASA Astrophysics Data System (ADS)

    Ohishi, Toshihiro

    The purpose of this paper is to show that the consideration of value is necessary to understand moral dilemmas in engineering ethics. First, the author shows that moral dilemmas are not fully understood in engineering ethics and argues that it is due to the lack of understanding of value. Second, the author considers the concept of value from the viewpoint of ‘desirability’ . Finally, three suggestions for improving engineering ethics in the understanding of moral dilemmas are made.

  16. Host and Environmental Specificity in Bacterial Communities Associated to Two Highly Invasive Marine Species (Genus Asparagopsis)

    PubMed Central

    Aires, Tânia; Serrão, Ester A.; Engelen, Aschwin H.

    2016-01-01

    As habitats change due to global and local pressures, population resilience, and adaptive processes depend not only on their gene pools but also on their associated bacteria communities. The hologenome can play a determinant role in adaptive evolution of higher organisms that rely on their bacterial associates for vital processes. In this study, we focus on the associated bacteria of the two most invasive seaweeds in southwest Iberia (coastal mainland) and nearby offshore Atlantic islands, Asparagopsis taxiformis and Asparagopsis armata. Bacterial communities were characterized using 16S rRNA barcoding through 454 next generation sequencing and exploratory shotgun metagenomics to provide functional insights and a backbone for future functional studies. The bacterial community composition was clearly different between the two species A. taxiformis and A. armata and between continental and island habitats. The latter was mainly due to higher abundances of Acidimicrobiales, Sphingomonadales, Xanthomonadales, Myxococcales, and Alteromonadales on the continent. Metabolic assignments for these groups contained a higher number of reads in functions related to oxidative stress and resistance to toxic compounds, more precisely heavy metals. These results are in agreement with their usual association with hydrocarbon degradation and heavy-metals detoxification. In contrast, A. taxiformis from islands contained more bacteria related to oligotrophic environments which might putatively play a role in mineralization of dissolved organic matter. The higher number of functional assignments found in the metagenomes of A. taxiformis collected from Cape Verde Islands suggest a higher contribution of bacteria to compensate nutrient limitation in oligotrophic environments. Our results show that Asparagopsis-associated bacterial communities have host-specificity and are modulated by environmental conditions. Whether this environmental effect reflects the host's selective requirements or

  17. Bacterial species and their associations with acute and chronic mastitis in suckler ewes.

    PubMed

    Smith, E M; Willis, Z N; Blakeley, M; Lovatt, F; Purdy, K J; Green, L E

    2015-10-01

    Acute mastitis in suckler ewes is often detected because of systemic signs such as anorexia or lameness, whereas chronic mastitis, characterized by intramammary abscesses with no systemic disease, is typically detected when ewes are inspected before mating. The aims of the current study were to identify the species and strains of culturable bacteria associated with acutely diseased, chronically diseased, and unaffected mammary glands to investigate whether species and strains vary by state. To investigate acute mastitis, 28 milk samples were obtained from both glands of 14 ewes with acute mastitis in one gland only. To investigate chronic mastitis, 16 ovine udders were obtained from 2 abattoirs; milk was aspirated from the 32 glands where possible, and the udders were sectioned to expose intramammary abscesses, which were swab sampled. All milk and swab samples were cultured aerobically. In total, 37 bacterial species were identified, 4 from acute mastitis, 26 from chronic mastitis, and 8 from apparently healthy glands. In chronic mastitis, the overall coincidence index of overlap of species detected in intramammary abscesses and milk was 0.60, reducing to 0.36 within individual glands, indicating a high degree of species overlap in milk and abscesses overall, but less overlap within specific glands. Staphylococcus aureus was detected frequently in all sample types; it was isolated from 10/14 glands with acute mastitis. In 5 ewes, closely related strains were present in both affected and unaffected glands. In chronic mastitis, closely related Staphylococcus aureus strains were detected in milk and abscesses from the same gland. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  18. Group size effect on cooperation in one-shot social dilemmas

    PubMed Central

    Barcelo, Hélène; Capraro, Valerio

    2015-01-01

    Social dilemmas are central to human society. Depletion of natural resources, climate protection, security of energy supply, and workplace collaborations are all examples of social dilemmas. Since cooperative behaviour in a social dilemma is individually costly, Nash equilibrium predicts that humans should not cooperate. Yet experimental studies show that people do cooperate even in anonymous one-shot interactions. In spite of the large number of participants in many modern social dilemmas, little is known about the effect of group size on cooperation. Does larger group size favour or prevent cooperation? We address this problem both experimentally and theoretically. Experimentally, we find that there is no general answer: it depends on the strategic situation. Specifically, we find that larger groups are more cooperative in the Public Goods game, but less cooperative in the N-person Prisoner's dilemma. Theoretically, we show that this behaviour is not consistent with either the Fehr & Schmidt model or (a one-parameter version of) the Charness & Rabin model, but it is consistent with the cooperative equilibrium model introduced by the second author. PMID:25605124

  19. Strong Regionality and Dominance of Anaerobic Bacterial Taxa Characterize Diazotrophic Bacterial Communities of the Arcto-Alpine Plant Species Oxyria digyna and Saxifraga oppositifolia.

    PubMed

    Kumar, Manoj; van Elsas, Jan Dirk; Nissinen, Riitta

    2017-01-01

    Arctic and alpine biomes are most often strongly nitrogen-limited, and hence biological nitrogen fixation is a strong driver of these ecosystems. Both biomes are characterized by low temperatures and short growing seasons, but they differ in seasonality of solar radiation and in soil water balance due to underlying permafrost in the Arctic. Arcto-alpine plant species are well-adapted to the low temperatures that prevail in their habitats, and plant growth is mainly limited by the availability of nutrients, in particular nitrogen, due to slow mineralization. Nitrogen fixing bacteria are likely important for plant growth in these habitats, but very little is known of these bacteria or forces shaping their communities. In this study, we characterized the potential nitrogen fixing bacterial (PNFB) communities associated with two arcto-alpine pioneer plant species, Oxyria digyna (mountain sorrel) and Saxifraga oppositifolia (blue saxifrage), in three climate regions. Both of these plants readily colonize low nutrient mineral soils. Our goal was to investigate how climate (region) and, on the other hand, host plant and plant species shape these communities. To our knowledge, this is the first comprehensive study describing PNFB communities associated with pioneer plants in different arcto-alpine biomes. Replicate samples were taken from two arctic regions, Kilpisjärvi and Ny-Ålesund, and one alpine region, Mayrhofen. In these, the PNFB communities in the bulk and rhizosphere soils and the plant endospheres were characterized by nifH -targeted PCR and massive parallel sequencing. The data revealed strong effects of climatic region on the dominating nitrogen fixers. Specifically, nifH sequences related to Geobacter (δ- Proteobacteria ) were present in high relative abundances in the nitrogen-fixing communities in the Mayrhofen and Kilpisjärvi regions, while members of the Clostridiales prevailed in the Kilpisjärvi and Ny-Ålesund regions. The bulk and rhizosphere soil

  20. Emergence of Super Cooperation of Prisoner’s Dilemma Games on Scale-Free Networks

    PubMed Central

    Li, Angsheng; Yong, Xi

    2015-01-01

    Recently, the authors proposed a quantum prisoner’s dilemma game based on the spatial game of Nowak and May, and showed that the game can be played classically. By using this idea, we proposed three generalized prisoner’s dilemma (GPD, for short) games based on the weak Prisoner’s dilemma game, the full prisoner’s dilemma game and the normalized Prisoner’s dilemma game, written by GPDW, GPDF and GPDN respectively. Our games consist of two players, each of which has three strategies: cooperator (C), defector (D) and super cooperator (denoted by Q), and have a parameter γ to measure the entangled relationship between the two players. We found that our generalised prisoner’s dilemma games have new Nash equilibrium principles, that entanglement is the principle of emergence and convergence (i.e., guaranteed emergence) of super cooperation in evolutions of our generalised prisoner’s dilemma games on scale-free networks, that entanglement provides a threshold for a phase transition of super cooperation in evolutions of our generalised prisoner’s dilemma games on scale-free networks, that the role of heterogeneity of the scale-free networks in cooperations and super cooperations is very limited, and that well-defined structures of scale-free networks allow coexistence of cooperators and super cooperators in the evolutions of the weak version of our generalised prisoner’s dilemma games. PMID:25643279

  1. Independent studies using deep sequencing resolve the same set of core bacterial species dominating gut communities of honey bees.

    PubMed

    Sabree, Zakee L; Hansen, Allison K; Moran, Nancy A

    2012-01-01

    Starting in 2003, numerous studies using culture-independent methodologies to characterize the gut microbiota of honey bees have retrieved a consistent and distinctive set of eight bacterial species, based on near identity of the 16S rRNA gene sequences. A recent study [Mattila HR, Rios D, Walker-Sperling VE, Roeselers G, Newton ILG (2012) Characterization of the active microbiotas associated with honey bees reveals healthier and broader communities when colonies are genetically diverse. PLoS ONE 7(3): e32962], using pyrosequencing of the V1-V2 hypervariable region of the 16S rRNA gene, reported finding entirely novel bacterial species in honey bee guts, and used taxonomic assignments from these reads to predict metabolic activities based on known metabolisms of cultivable species. To better understand this discrepancy, we analyzed the Mattila et al. pyrotag dataset. In contrast to the conclusions of Mattila et al., we found that the large majority of pyrotag sequences belonged to clusters for which representative sequences were identical to sequences from previously identified core species of the bee microbiota. On average, they represent 95% of the bacteria in each worker bee in the Mattila et al. dataset, a slightly lower value than that found in other studies. Some colonies contain small proportions of other bacteria, mostly species of Enterobacteriaceae. Reanalysis of the Mattila et al. dataset also did not support a relationship between abundances of Bifidobacterium and of putative pathogens or a significant difference in gut communities between colonies from queens that were singly or multiply mated. Additionally, consistent with previous studies, the dataset supports the occurrence of considerable strain variation within core species, even within single colonies. The roles of these bacteria within bees, or the implications of the strain variation, are not yet clear.

  2. Ethical dilemmas experienced by speech-language pathologists working in private practice.

    PubMed

    Flatley, Danielle R; Kenny, Belinda J; Lincoln, Michelle A

    2014-06-01

    Speech-language pathologists experience ethical dilemmas as they fulfil their professional roles and responsibilities. Previous research findings indicated that speech-language pathologists working in publicly funded settings identified ethical dilemmas when they managed complex clients, negotiated professional relationships, and addressed service delivery issues. However, little is known about ethical dilemmas experienced by speech-language pathologists working in private practice settings. The aim of this qualitative study was to describe the nature of ethical dilemmas experienced by speech-language pathologists working in private practice. Data were collected through semi-structured interviews with 10 speech-language pathologists employed in diverse private practice settings. Participants explained the nature of ethical dilemmas they experienced at work and identified their most challenging and frequently occurring ethical conflicts. Qualitative content analysis was used to analyse transcribed data and generate themes. Four themes reflected the nature of speech-language pathologists' ethical dilemmas; balancing benefit and harm, fidelity of business practices, distributing funds, and personal and professional integrity. Findings support the need for professional development activities that are specifically targeted towards facilitating ethical practice for speech-language pathologists in the private sector.

  3. Exploration of bacterial species associated with the salivary microbiome of individuals with a low susceptibility to dental caries.

    PubMed

    Yasunaga, Haruna; Takeshita, Toru; Shibata, Yukie; Furuta, Michiko; Shimazaki, Yoshihiro; Akifusa, Sumio; Ninomiya, Toshiharu; Kiyohara, Yutaka; Takahashi, Ichiro; Yamashita, Yoshihisa

    2017-11-01

    Dental caries is caused by acidogenic plaque microbiota formed on saliva-bathed tooth surfaces, in which multiple organisms act collectively to initiate and expand a cavity. We explored bacterial species associated with the salivary microbiome of individuals with low susceptibility to dental caries. The bacterial composition of saliva from 19 young adults was analyzed using barcoded pyrosequencing of the 16S rRNA gene; we compared 10 caries-experienced (CE) and nine caries-free (CF) individuals. A quantitative PCR assay of saliva from 139 orally healthy adults aged 40-59 years was carried out to confirm the result obtained by pyrosequencing analysis. The microbiomes of CF individuals showed more diverse communities with a significantly greater proportion of the genus Porphyromonas. Among operational taxonomic units (OTUs) corresponding to the genus Porphyromonas, the OTU corresponding to P. pasteri was the most predominant and its relative abundance in CF individuals was significantly greater than in CE individuals (P < 0.001, Wilcoxon rank sum test). A quantitative PCR assay of saliva confirmed that the amounts of P. pasteri were significantly higher in individuals with lower caries experience (filled teeth <15, n = 67) than in those with higher caries experience (filled teeth ≥15, n = 72) (P < 0.001, Student's t test). These results revealed an association between a greater abundance of P. pasteri and lower susceptibility to dental caries. P. pasteri may be a bacterial species that could potentially be used as a marker for maintaining a healthy oral microbiome against dental caries.

  4. Partner choice cooperation in prisoner's dilemma

    NASA Astrophysics Data System (ADS)

    Wang, Qi; Xu, Zhaojin; Zhang, Lianzhong

    2017-12-01

    In this paper, we investigated the cooperative behavior in prisoner's dilemma when the individual behaviors and interaction structures could coevolve. Here, we study the model that the individuals can imitate the strategy of their neighbors and rewire their social ties throughout evolution, based exclusively on a fitness comparison. We find that the cooperation can be achieved if the time scale of network adaptation is large enough, even when the social dilemma strength is very strong. Detailed investigation shows that the presence or absence of the network adaptation has a profound impact on the collective behavior in the system.

  5. Bacterial Diversity in Human Subgingival Plaque

    PubMed Central

    Paster, Bruce J.; Boches, Susan K.; Galvin, Jamie L.; Ericson, Rebecca E.; Lau, Carol N.; Levanos, Valerie A.; Sahasrabudhe, Ashish; Dewhirst, Floyd E.

    2001-01-01

    The purpose of this study was to determine the bacterial diversity in the human subgingival plaque by using culture-independent molecular methods as part of an ongoing effort to obtain full 16S rRNA sequences for all cultivable and not-yet-cultivated species of human oral bacteria. Subgingival plaque was analyzed from healthy subjects and subjects with refractory periodontitis, adult periodontitis, human immunodeficiency virus periodontitis, and acute necrotizing ulcerative gingivitis. 16S ribosomal DNA (rDNA) bacterial genes from DNA isolated from subgingival plaque samples were PCR amplified with all-bacterial or selective primers and cloned into Escherichia coli. The sequences of cloned 16S rDNA inserts were used to determine species identity or closest relatives by comparison with sequences of known species. A total of 2,522 clones were analyzed. Nearly complete sequences of approximately 1,500 bases were obtained for putative new species. About 60% of the clones fell into 132 known species, 70 of which were identified from multiple subjects. About 40% of the clones were novel phylotypes. Of the 215 novel phylotypes, 75 were identified from multiple subjects. Known putative periodontal pathogens such as Porphyromonas gingivalis, Bacteroides forsythus, and Treponema denticola were identified from multiple subjects, but typically as a minor component of the plaque as seen in cultivable studies. Several phylotypes fell into two recently described phyla previously associated with extreme natural environments, for which there are no cultivable species. A number of species or phylotypes were found only in subjects with disease, and a few were found only in healthy subjects. The organisms identified only from diseased sites deserve further study as potential pathogens. Based on the sequence data in this study, the predominant subgingival microbial community consisted of 347 species or phylotypes that fall into 9 bacterial phyla. Based on the 347 species seen in our

  6. An Analysis of Student Choices in Medical Ethical Dilemmas.

    ERIC Educational Resources Information Center

    Woloshin, Phyllis Lerman

    This report describes a study undertaken to assess student choices in medical ethical dilemmas. Medical ethical dilemmas are interpreted to include problems such as abortion, euthanasia, sterilization, experimentation on humans, allocation of scarce medical resources, and physician and health personnel training. The major purpose of the study was…

  7. Pathogenic Leptospira species express surface-exposed proteins belonging to the bacterial immunoglobulin superfamily

    PubMed Central

    Matsunaga, James; Barocchi, Michele A.; Croda, Julio; Young, Tracy A.; Sanchez, Yolanda; Siqueira, Isadora; Bolin, Carole A.; Reis, Mitermayer G.; Riley, Lee W.; Haake, David A.; Ko, Albert I.

    2005-01-01

    Summary Proteins with bacterial immunoglobulin-like (Big) domains, such as the Yersinia pseudotuberculosis invasin and Escherichia coli intimin, are surface-expressed proteins that mediate host mammalian cell invasion or attachment. Here, we report the identification and characterization of a new family of Big domain proteins, referred to as Lig (leptospiral Ig-like) proteins, in pathogenic Leptospira. Screening of L. interrogans and L. kirschneri expression libraries with sera from leptospirosis patients identified 13 lambda phage clones that encode tandem repeats of the 90 amino acid Big domain. Two lig genes, designated ligA and ligB, and one pseudo-gene, ligC, were identified. The ligA and ligB genes encode amino-terminal lipoprotein signal peptides followed by 10 or 11 Big domain repeats and, in the case of ligB, a unique carboxy-terminal non-repeat domain. The organization of ligC is similar to that of ligB but contains mutations that disrupt the reading frame. The lig sequences are present in pathogenic but not saprophytic Leptospira species. LigA and LigB are expressed by a variety of virulent leptospiral strains. Loss of Lig protein and RNA transcript expression is correlated with the observed loss of virulence during culture attenuation of pathogenic strains. High-pressure freeze substitution followed by immunocytochemical electron microscopy confirmed that the Lig proteins were localized to the bacterial surface. Immunoblot studies with patient sera found that the Lig proteins are a major antigen recognized during the acute host infection. These observations demonstrate that the Lig proteins are a newly identified surface protein of pathogenic Leptospira, which by analogy to other bacterial immunoglobulin superfamily virulence factors, may play a role in host cell attachment and invasion during leptospiral pathogenesis. PMID:12890019

  8. Pathogenic Leptospira species express surface-exposed proteins belonging to the bacterial immunoglobulin superfamily.

    PubMed

    Matsunaga, James; Barocchi, Michele A; Croda, Julio; Young, Tracy A; Sanchez, Yolanda; Siqueira, Isadora; Bolin, Carole A; Reis, Mitermayer G; Riley, Lee W; Haake, David A; Ko, Albert I

    2003-08-01

    Proteins with bacterial immunoglobulin-like (Big) domains, such as the Yersinia pseudotuberculosis invasin and Escherichia coli intimin, are surface-expressed proteins that mediate host mammalian cell invasion or attachment. Here, we report the identification and characterization of a new family of Big domain proteins, referred to as Lig (leptospiral Ig-like) proteins, in pathogenic Leptospira. Screening of L. interrogans and L. kirschneri expression libraries with sera from leptospirosis patients identified 13 lambda phage clones that encode tandem repeats of the 90 amino acid Big domain. Two lig genes, designated ligA and ligB, and one pseudogene, ligC, were identified. The ligA and ligB genes encode amino-terminal lipoprotein signal peptides followed by 10 or 11 Big domain repeats and, in the case of ligB, a unique carboxy-terminal non-repeat domain. The organization of ligC is similar to that of ligB but contains mutations that disrupt the reading frame. The lig sequences are present in pathogenic but not saprophytic Leptospira species. LigA and LigB are expressed by a variety of virulent leptospiral strains. Loss of Lig protein and RNA transcript expression is correlated with the observed loss of virulence during culture attenuation of pathogenic strains. High-pressure freeze substitution followed by immunocytochemical electron microscopy confirmed that the Lig proteins were localized to the bacterial surface. Immunoblot studies with patient sera found that the Lig proteins are a major antigen recognized during the acute host infection. These observations demonstrate that the Lig proteins are a newly identified surface protein of pathogenic Leptospira, which by analogy to other bacterial immunoglobulin superfamily virulence factors, may play a role in host cell attachment and invasion during leptospiral pathogenesis.

  9. European Portuguese adaptation and validation of dilemmas used to assess moral decision-making.

    PubMed

    Fernandes, Carina; Gonçalves, Ana Ribeiro; Pasion, Rita; Ferreira-Santos, Fernando; Paiva, Tiago Oliveira; Melo E Castro, Joana; Barbosa, Fernando; Martins, Isabel Pavão; Marques-Teixeira, João

    2018-03-01

    Objective To adapt and validate a widely used set of moral dilemmas to European Portuguese, which can be applied to assess decision-making. Moreover, the classical formulation of the dilemmas was compared with a more focused moral probe. Finally, a shorter version of the moral scenarios was tested. Methods The Portuguese version of the set of moral dilemmas was tested in 53 individuals from several regions of Portugal. In a second study, an alternative way of questioning on moral dilemmas was tested in 41 participants. Finally, the shorter version of the moral dilemmas was tested in 137 individuals. Results Results evidenced no significant differences between English and Portuguese versions. Also, asking whether actions are "morally acceptable" elicited less utilitarian responses than the original question, although without reaching statistical significance. Finally, all tested versions of moral dilemmas exhibited the same pattern of responses, suggesting that the fundamental elements to the moral decision-making were preserved. Conclusions We found evidence of cross-cultural validity for moral dilemmas. However, the moral focus might affect utilitarian/deontological judgments.

  10. Leadership styles of nurse managers in ethical dilemmas: Reasons and consequences.

    PubMed

    Zydziunaite, Vilma; Suominen, Tarja

    2014-01-01

    Abstract Background: Understanding the reasons and consequences of leadership styles in ethical dilemmas is fundamental to exploring nurse managers' abilities to influence outcomes for patients and nursing personnel. To explain the associations between different leadership styles, reasons for their application and its consequences when nurse managers make decisions in ethical dilemmas. The data were collected between 15 October 2011 and 30 April 2012 by statistically validated questionnaire. The respondents (N = 278) were nurse managers. The data were analysed using SPSS 20.0, calculating Spearman's correlations, the Stepwise Regression and ANOVA. The reasons for applying different leadership styles in ethical dilemmas include personal characteristics, years in work position, institutional factors, and the professional authority of nurse managers. The applied leadership styles in ethical dilemmas are associated with the consequences regarding the satisfaction of patients,' relatives' and nurse managers' needs. Nurse managers exhibited leadership styles oriented to maintenance, focussing more on the 'doing the job' than on managing the decision-making in ethical dilemmas.

  11. Environmental Education Research in Southern Africa: Dilemmas of Interpretation

    ERIC Educational Resources Information Center

    Gough, Annette; Gough, Noel

    2004-01-01

    These multiple framings of our reflections on environmental education research in southern Africa are written as dilemmas of interpretation that aim to disrupt any temptation to generalise or essentialise its qualities and characteristics. Recognising that research is a textual practice, we use J. M. Coetzee's portrayal of the dilemmas faced by…

  12. Success and Failure of Parliamentary Motions: A Social Dilemma Approach.

    PubMed

    Popping, Roel; Wittek, Rafael

    2015-01-01

    Parliamentary motions are a vital and frequently used element of political control in democratic regimes. Despite their high incidence and potential impact on the political fate of a government and its policies, we know relatively little about the conditions under which parliamentary motions are likely to be accepted or rejected. Current collective decision-making models use a voting power framework in which power and influence of the involved parties are the main predictors. We propose an alternative, social dilemma approach, according to which a motion's likelihood to be accepted depends on the severity of the social dilemma underlying the decision issue. Actor- and dilemma-centered hypotheses are developed and tested with data from a stratified random sample of 822 motions that have been voted upon in the Dutch Parliament between September 2009 and February 2011. The social dilemma structure of each motion is extracted through content coding, applying a cognitive mapping technique developed by Anthony, Heckathorn and Maser. Logistic regression analyses are in line with both, actor-centered and social-dilemma centered approaches, though the latter show stronger effect sizes. Motions have a lower chance to be accepted if voting potential is low, the proposer is not from the voting party, and if the problem underlying the motion reflects a prisoner's dilemma or a pure competition game as compared to a coordination game. The number of proposing parties or a battle of the sexes structure does not significantly affect the outcome.

  13. Success and Failure of Parliamentary Motions: A Social Dilemma Approach

    PubMed Central

    Popping, Roel; Wittek, Rafael

    2015-01-01

    Parliamentary motions are a vital and frequently used element of political control in democratic regimes. Despite their high incidence and potential impact on the political fate of a government and its policies, we know relatively little about the conditions under which parliamentary motions are likely to be accepted or rejected. Current collective decision-making models use a voting power framework in which power and influence of the involved parties are the main predictors. We propose an alternative, social dilemma approach, according to which a motion’s likelihood to be accepted depends on the severity of the social dilemma underlying the decision issue. Actor- and dilemma-centered hypotheses are developed and tested with data from a stratified random sample of 822 motions that have been voted upon in the Dutch Parliament between September 2009 and February 2011. The social dilemma structure of each motion is extracted through content coding, applying a cognitive mapping technique developed by Anthony, Heckathorn and Maser. Logistic regression analyses are in line with both, actor-centered and social-dilemma centered approaches, though the latter show stronger effect sizes. Motions have a lower chance to be accepted if voting potential is low, the proposer is not from the voting party, and if the problem underlying the motion reflects a prisoner’s dilemma or a pure competition game as compared to a coordination game. The number of proposing parties or a battle of the sexes structure does not significantly affect the outcome. PMID:26317869

  14. Philanthropic dilemmas and the nurse administrator role.

    PubMed

    Klein, Tracy

    2014-01-01

    Nurse administrators are in a position to encounter ethical dilemmas when evaluating philanthropic proposals. Nurses may have little formal training in ethics, or they may be most experienced with ethical frameworks that apply primarily to clinical patient encounters. Gifts of goods, services, education, or other benefits to nurses may create ethical dilemmas. Philanthropic ethics and potential dilemmas are discussed in nonnursing professions such as medicine and nonprofit administration but rarely explored in the nursing administration context. Nurse administrators in a position to evaluate generous offers of philanthropy should identify key components to fully assess the ethics of their receipt. A survey of several resources is done to provide nurse administrators with the foundation to develop policies related to philanthropy if they are absent, preferably in advance of the offer. Recommendations for assessment and evaluation of philanthropic proposals are provided to aid nurse administrators in their synthesis and application of ethical principles from multiple sources.

  15. Characterization of initial events in bacterial surface colonization by two Pseudomonas species using image analysis.

    PubMed

    Mueller, R F; Characklis, W G; Jones, W L; Sears, J T

    1992-05-01

    The processes leading to bacterial colonization on solid-water interfaces are adsorption, desorption, growth, and erosion. These processes have been measured individually in situ in a flowing system in real time using image analysis. Four different substrata (copper, silicon, 316 stainless-steel and glass) and 2 different bacterial species (Pseudomonas aeruginosa and Pseudomonas fluorescens) were used in the experiments. The flow was laminar (Re = 1.4) and the shear stress was kept constant during all experiments at 0.75 N m(-2). The surface roughness varied among the substrata from 0.002 microm (for silicon) to 0.015 microm (for copper). Surface free energies varied from 25.1 dynes cm(-1) for silicon to 31.2 dynes cm(-1) for copper. Cell curface hydrophobicity, reported as hydrocarbon partitioning values, ranged from 0.67 for Ps. fluorescens to 0.97 for Ps. aeruginosa.The adsorption rate coefficient varied by as much as a factor of 10 among the combinations of bacterial strain and substratum material, and was positively correlated with surface free energy, the surface roughness of the substratum, and the hydrophobicity of the cells. The probability of desorption decreased with increasing surface free energy and surface roughness of the substratum. Cell growth was inhibited on copper, but replication of cells overlying an initial cell layer was observed with increased exposure time to the cell-containing bulk water. A mathematical model describing cell accumulation on a substratum is presented.

  16. The Cattle-Wolf Dilemma: Interactions among Three Protected Species

    NASA Astrophysics Data System (ADS)

    Becker, Nir; Farja, Yanay

    2017-02-01

    This paper utilizes economic valuation to offer a new perspective on livestock rancher—predator conflicts. While most studies have considered losses to the species directly involved, i.e., cattle and wolves ( Canis lupus), we take into account other species that are threatened by efforts to protect livestock. In this case, vultures ( Gyps fulvus) and gazelles ( Gazella gazella), both endangered species, are either poisoned (vultures) or suffer from habitat fragmentation (gazelles) in the Upper Galilee region in Israel. Since the ecological value of these species is unobserved in the marketplace, we use the contingent valuation method to quantify the loss incurred from damage to protected species: wolves, vultures and gazelles. This method uses surveys of a representative sample from the population to generate estimates for use and non-use values of animals and other components of the natural environment. These value estimates are then used to compare between different measures that address the problem: either protect cattle herds by building anti-wolf fences and taking other protective measures, or compensating ranchers for their losses from wolf depredations. Our analysis suggests that while it is optimal from the ranchers' point of view to invest in protective measures such as fences, dogs and guards against wolves, it is not in society's best interest. A cost-benefit analysis taking into account all the ecological values finds a higher net benefit to society from a relatively small amount of protection, coupled with compensation to the farmers for depredations.

  17. Bacterial diversity at different stages of the composting process

    PubMed Central

    2010-01-01

    Background Composting is an aerobic microbiological process that is facilitated by bacteria and fungi. Composting is also a method to produce fertilizer or soil conditioner. Tightened EU legislation now requires treatment of the continuously growing quantities of organic municipal waste before final disposal. However, some full-scale composting plants experience difficulties with the efficiency of biowaste degradation and with the emission of noxious odours. In this study we examine the bacterial species richness and community structure of an optimally working pilot-scale compost plant, as well as a full-scale composting plant experiencing typical problems. Bacterial species composition was determined by isolating total DNA followed by amplifying and sequencing the gene encoding the 16S ribosomal RNA. Results Over 1500 almost full-length 16S rRNA gene sequences were analysed and of these, over 500 were present only as singletons. Most of the sequences observed in either one or both of the composting processes studied here were similar to the bacterial species reported earlier in composts, including bacteria from the phyla Actinobacteria, Bacteroidetes, Firmicutes, Proteobacteria and Deinococcus-Thermus. In addition, a number of previously undetected bacterial phylotypes were observed. Statistical calculations estimated a total bacterial diversity of over 2000 different phylotypes in the studied composts. Conclusions Interestingly, locally enriched or evolved bacterial variants of familiar compost species were observed in both composts. A detailed comparison of the bacterial diversity revealed a large difference in composts at the species and strain level from the different composting plants. However, at the genus level, the difference was much smaller and illustrated a delay of the composting process in the full-scale, sub-optimally performing plants. PMID:20350306

  18. Bacteriophage Amplification-Coupled Detection and Identification of Bacterial Pathogens

    NASA Astrophysics Data System (ADS)

    Cox, Christopher R.; Voorhees, Kent J.

    Current methods of species-specific bacterial detection and identification are complex, time-consuming, and often require expensive specialized equipment and highly trained personnel. Numerous biochemical and genotypic identification methods have been applied to bacterial characterization, but all rely on tedious microbiological culturing practices and/or costly sequencing protocols which render them impractical for deployment as rapid, cost-effective point-of-care or field detection and identification methods. With a view towards addressing these shortcomings, we have exploited the evolutionarily conserved interactions between a bacteriophage (phage) and its bacterial host to develop species-specific detection methods. Phage amplification-coupled matrix assisted laser desorption time-of-flight mass spectrometry (MALDI-TOF-MS) was utilized to rapidly detect phage propagation resulting from species-specific in vitro bacterial infection. This novel signal amplification method allowed for bacterial detection and identification in as little as 2 h, and when combined with disulfide bond reduction methods developed in our laboratory to enhance MALDI-TOF-MS resolution, was observed to lower the limit of detection by several orders of magnitude over conventional spectroscopy and phage typing methods. Phage amplification has been combined with lateral flow immunochromatography (LFI) to develop rapid, easy-to-operate, portable, species-specific point-of-care (POC) detection devices. Prototype LFI detectors have been developed and characterized for Yersinia pestis and Bacillus anthracis, the etiologic agents of plague and anthrax, respectively. Comparable sensitivity and rapidity was observed when phage amplification was adapted to a species-specific handheld LFI detector, thus allowing for rapid, simple, POC bacterial detection and identification while eliminating the need for bacterial culturing or DNA isolation and amplification techniques.

  19. Ethical dilemmas in geosciences. We can ask, but, can we ans?

    NASA Astrophysics Data System (ADS)

    Marone, Eduardo

    2016-04-01

    Philosophy tries to provide rules and principles enabling us to solve the ethical dilemmas we face in a wide sense, and, also, in particular fields as (geo)sciences. One alleged goal of ethics is to figure out how to solve ethical dilemmas. But, is it possible to solve such dilemmas? And what can we do if we cannot? An ethical dilemma is a problem that offers an alternative between two or more solutions, none of which proves to be fully acceptable in practice. Dilemmas arise because of conflict between the rightness or wrongness of the actions/means and the goodness or badness of the consequences/ends. They involve an apparent conflict between moral imperatives, in which to follow one would result in violating another. Can a geoscientist answer those dilemmas that appear in the exercise of his/her profession? Always? In some cases? Not at all? What if we cannot? Have we? As geoscientists, we hold the knowledge (our scientific principles), not perfect, thus fallible, and always subject to changes and improvements. If we have to do what is right, based on our principles, despite potentially bad consequences, then we have to be sure that the principle is an absolute true. But, are our scientific principles such a true? Deontological theories may deny that consequences are of any concern, provided the intention was a good one. However, if our principles are not perfect (and we know that): can we answer in one or other direction to geoethical dilemmas in good faith? Although, if a geoscientist action does usually go for the best consequences, sometimes bad consequences may be accepted. But, who have to decide to accept the bad consequences? If ethical dilemmas with a conflict between means and ends cannot simply be solved by a geoscientist, where is our duty? If there is no real solution to the conflict of the right with the good, in the sense that a solution usually seems to be expected, what has to be our professional attitude? When we have duties of omission and when

  20. Mineral Types and Tree Species Determine the Functional and Taxonomic Structures of Forest Soil Bacterial Communities.

    PubMed

    Colin, Y; Nicolitch, O; Turpault, M-P; Uroz, S

    2017-03-01

    mineralogy influences the diversity, structure, and function of soil bacterial communities in relation to the soil conditions is crucial to better understanding the relative role of the soil bacterial communities in nutrient cycling and plant nutrition in nutrient-poor environments. The present study determined in detail the diversity and structure of bacterial communities associated with different mineral types incubated for 2.5 years in the soil under different tree species using cultivation-dependent and -independent analyses. Our data showed an enrichment of specific bacterial taxa on the minerals, specifically on the most weathered minerals, suggesting that they play key roles in mineral weathering and nutrient cycling in nutrient-poor forest ecosystems. Copyright © 2017 American Society for Microbiology.

  1. Mineral Types and Tree Species Determine the Functional and Taxonomic Structures of Forest Soil Bacterial Communities

    PubMed Central

    Colin, Y.; Nicolitch, O.; Turpault, M.-P.

    2016-01-01

    how soil mineralogy influences the diversity, structure, and function of soil bacterial communities in relation to the soil conditions is crucial to better understanding the relative role of the soil bacterial communities in nutrient cycling and plant nutrition in nutrient-poor environments. The present study determined in detail the diversity and structure of bacterial communities associated with different mineral types incubated for 2.5 years in the soil under different tree species using cultivation-dependent and -independent analyses. Our data showed an enrichment of specific bacterial taxa on the minerals, specifically on the most weathered minerals, suggesting that they play key roles in mineral weathering and nutrient cycling in nutrient-poor forest ecosystems. PMID:28003192

  2. Non-Official Roads Dilemma in Amazonia

    NASA Technical Reports Server (NTRS)

    Perz, Stephen G.; Arima, Eugenio; Souza, Carlos, Jr.; Caldas, Marcellus; Brandao, Amintas de O., Jr.; Araujo de Souza, Francisco Kennedy; Walker, Robert

    2005-01-01

    At the beginning of this millennium, "non-official" roads predominate in Amazonia. The opening of these roads, a phenomenon that has not been studied in depth, represents a major dilemma - it generates environmental and social impacts, but it helps to reduce the isolation of the communities in Amazonia and to improve the quality of life for those rural populations. The combined positive and negative aspects of this dilemma mean that it is a matter of crucial importance for the government at last to do a proper job in building these roads; if this is disregarded, in the future, the environment and the Brazilians living in that region will be at risk.

  3. Differentiation of bacterial colonies and temporal growth patterns using hyperspectral imaging

    NASA Astrophysics Data System (ADS)

    Mehrübeoglu, Mehrube; Buck, Gregory W.; Livingston, Daniel W.

    2014-09-01

    Detection and identification of bacteria are important for health and safety. Hyperspectral imaging offers the potential to capture unique spectral patterns and spatial information from bacteria which can then be used to detect and differentiate bacterial species. Here, hyperspectral imaging has been used to characterize different bacterial colonies and investigate their growth over time. Six bacterial species (Pseudomonas fluorescens, Escherichia coli, Serratia marcescens, Salmonella enterica, Staphylococcus aureus, Enterobacter aerogenes) were grown on tryptic soy agar plates. Hyperspectral data were acquired immediately after, 24 hours after, and 96 hours after incubation. Spectral signatures from bacterial colonies demonstrated repeatable measurements for five out of six species. Spatial variations as well as changes in spectral signatures were observed across temporal measurements within and among species at multiple wavelengths due to strengthening or weakening reflectance signals from growing bacterial colonies based on their pigmentation. Between-class differences and within-class similarities were the most prominent in hyperspectral data collected 96 hours after incubation.

  4. Trust, trolleys and social dilemmas: A replication study.

    PubMed

    Bostyn, Dries H; Roets, Arne

    2017-05-01

    The present manuscript addresses how perceived trustworthiness of cooperative partners in a social dilemma context is influenced by the moral judgments those partners make on Trolley-type moral dilemmas; an issue recently investigated by Everett, Pizarro, and Crockett (2016). The present research comprises 2 studies that were conducted independently, simultaneously with, and incognizant of the Everett studies. Whereas the present studies aimed at investigating the same research hypothesis, a different and more elaborate methodology was used, as such providing a conceptual replication opportunity and extension to the Everett et al. Overall, the present studies clearly confirmed the main finding of Everett et al., that deontologists are more trusted than consequentialists in social dilemma games. Study 1 replicates Everett et al.'s effect in the context of trust games. Study 2 generalizes the effect to public goods games, thus demonstrating that it is not specific to the type of social dilemma game used in Everett et al. Finally, both studies build on these results by demonstrating that the increased trust in deontologists may sometimes, but not always, be warranted: deontologists displayed increased cooperation rates but only in the public goods game and not in trust games. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  5. The great downside dilemma for risky emerging technologies

    NASA Astrophysics Data System (ADS)

    Baum, Seth D.

    2014-12-01

    Some emerging technologies promise to significantly improve the human condition, but come with a risk of failure so catastrophic that human civilization may not survive. This article discusses the great downside dilemma posed by the decision of whether or not to use these technologies. The dilemma is: use the technology, and risk the downside of catastrophic failure, or do not use the technology, and suffer through life without it. Historical precedents include the first nuclear weapon test and messaging to extraterrestrial intelligence. Contemporary examples include stratospheric geoengineering, a technology under development in response to global warming, and artificial general intelligence, a technology that could even take over the world. How the dilemma should be resolved depends on the details of each technology’s downside risk and on what the human condition would otherwise be. Meanwhile, other technologies do not pose this dilemma, including sustainable design technologies, nuclear fusion power, and space colonization. Decisions on all of these technologies should be made with the long-term interests of human civilization in mind. This paper is part of a series of papers based on presentations at the Emerging Technologies and the Future of Humanity event held at the Royal Swedish Academy of Sciences on 17 March 2014.

  6. Bacterial Identification Using Light Scattering Measurements: a Preliminary Report

    NASA Technical Reports Server (NTRS)

    Wilkins, J. R.

    1971-01-01

    The light scattering properties of single bacterial cells were examined as a possible means of identification. Three species were studied with streptococcus faecalis exhibiting a unique pattern; the light-scattering traces for staphylococcus aureus and escherichia coli were quite similar although differences existed. Based on preliminary investigations, the light scattering approach appeared promising with additional research needed to include a wide variety of bacterial species, computer capability to handle and analyze data, and expansion of light scattering theory to include bacterial cells.

  7. Periodic growth of bacterial colonies

    NASA Astrophysics Data System (ADS)

    Yamazaki, Yoshihiro; Ikeda, Takemasa; Shimada, Hirotoshi; Hiramatsu, Fumiko; Kobayashi, Naoki; Wakita, Jun-ichi; Itoh, Hiroto; Kurosu, Sayuri; Nakatsuchi, Michio; Matsuyama, Tohey; Matsushita, Mitsugu

    2005-06-01

    The formation of concentric ring colonies by bacterial species Bacillus subtilis and Proteus mirabilis has been investigated experimentally, focusing our attention on the dependence of local cell density upon the bacterial motility. It has been confirmed that these concentric ring colonies reflect the periodic change of the bacterial motility between motile cell state and immotile cell state. We conclude that this periodic change is macroscopically determined neither by biological factors (i.e., biological clock) nor by chemical factors (chemotaxis as inhibitor). And our experimental results strongly suggest that the essential factor for the change of the bacterial motility during concentric ring formation is the local cell density.

  8. Effect of Weak Magnetic Field on Bacterial Growth

    NASA Astrophysics Data System (ADS)

    Masood, Samina

    Effects of weak magnetic fields are observed on the growth of various bacterial strains. Different sources of a constant magnetic field are used to demonstrate that ion transport in the nutrient broth and bacterial cellular dynamics is perturbed in the presence of weak magnetic field which affects the mobility and absorption of nutrients in cells and hence their doubling rate. The change is obvious after a few hours of exposure and keeps on increasing with time for all the observed species. The growth rate depends on the field strength and the nature of the magnetic field. The field effect varies with the shape and the structure of the bacterial cell wall as well as the concentration of nutrient broth. We closely study the growth of three species Escherichia coli, Pseudomonas aeruginosa and Staphylococcus epidermidis with the same initial concentrations at the same temperature in the same laboratory environment. Our results indicate that the weak static field of a few gauss after a few hours gives a measurable change in the growth rates of all bacterial species. This shows that the same magnetic field has different effects on different species in the same environment.

  9. The intrinsic resistome of bacterial pathogens

    PubMed Central

    Olivares, Jorge; Bernardini, Alejandra; Garcia-Leon, Guillermo; Corona, Fernando; B. Sanchez, Maria; Martinez, Jose L.

    2013-01-01

    Intrinsically resistant bacteria have emerged as a relevant health problem in the last years. Those bacterial species, several of them with an environmental origin, present naturally low-level susceptibility to several drugs. It has been proposed that intrinsic resistance is mainly the consequence of the impermeability of cellular envelopes, the activity of multidrug efflux pumps or the lack of appropriate targets for a given family of drugs. However, recently published articles indicate that the characteristic phenotype of susceptibility to antibiotics of a given bacterial species depends on the concerted activity of several elements, what has been named as intrinsic resistome. These determinants comprise not just classical resistance genes. Other elements, several of them involved in basic bacterial metabolic processes, are of relevance for the intrinsic resistance of bacterial pathogens. In the present review we analyze recent publications on the intrinsic resistomes of Escherichia coli and Pseudomonas aeruginosa. We present as well information on the role that global regulators of bacterial metabolism, as Crc from P. aeruginosa, may have on modulating bacterial susceptibility to antibiotics. Finally, we discuss the possibility of searching inhibitors of the intrinsic resistome in the aim of improving the activity of drugs currently in use for clinical practice. PMID:23641241

  10. The intrinsic resistome of bacterial pathogens.

    PubMed

    Olivares, Jorge; Bernardini, Alejandra; Garcia-Leon, Guillermo; Corona, Fernando; B Sanchez, Maria; Martinez, Jose L

    2013-01-01

    Intrinsically resistant bacteria have emerged as a relevant health problem in the last years. Those bacterial species, several of them with an environmental origin, present naturally low-level susceptibility to several drugs. It has been proposed that intrinsic resistance is mainly the consequence of the impermeability of cellular envelopes, the activity of multidrug efflux pumps or the lack of appropriate targets for a given family of drugs. However, recently published articles indicate that the characteristic phenotype of susceptibility to antibiotics of a given bacterial species depends on the concerted activity of several elements, what has been named as intrinsic resistome. These determinants comprise not just classical resistance genes. Other elements, several of them involved in basic bacterial metabolic processes, are of relevance for the intrinsic resistance of bacterial pathogens. In the present review we analyze recent publications on the intrinsic resistomes of Escherichia coli and Pseudomonas aeruginosa. We present as well information on the role that global regulators of bacterial metabolism, as Crc from P. aeruginosa, may have on modulating bacterial susceptibility to antibiotics. Finally, we discuss the possibility of searching inhibitors of the intrinsic resistome in the aim of improving the activity of drugs currently in use for clinical practice.

  11. Relationship of periodontal clinical parameters with bacterial composition in human dental plaque.

    PubMed

    Fujinaka, Hidetake; Takeshita, Toru; Sato, Hirayuki; Yamamoto, Tetsuji; Nakamura, Junji; Hase, Tadashi; Yamashita, Yoshihisa

    2013-06-01

    More than 600 bacterial species have been identified in the oral cavity, but only a limited number of species show a strong association with periodontitis. The purpose of the present study was to provide a comprehensive outline of the microbiota in dental plaque related to periodontal status. Dental plaque from 90 subjects was sampled, and the subjects were clustered based on bacterial composition using the terminal restriction fragment length polymorphism of 16S rRNA genes. Here, we evaluated (1) periodontal clinical parameters between clusters; (2) the correlation of subgingival bacterial composition with supragingival bacterial composition; and (3) the association between bacterial interspecies in dental plaque using a graphical Gaussian model. Cluster 1 (C1) having high prevalence of pathogenic bacteria in subgingival plaque showed increasing values of the parameters. The values of the parameters in Cluster 2a (C2a) having high prevalence of non-pathogenic bacteria were markedly lower than those in C1. A cluster having low prevalence of non-pathogenic bacteria in supragingival plaque showed increasing values of the parameters. The bacterial patterns between subgingival plaque and supragingival plaque were significantly correlated. Chief pathogens, such as Porphyromonas gingivalis, formed a network with other pathogenic species in C1, whereas a network of non-pathogenic species, such as Rothia sp. and Lautropia sp., tended to compete with a network of pathogenic species in C2a. Periodontal status relates to non-pathogenic species as well as to pathogenic species, suggesting that the bacterial interspecies connection affects dental plaque virulence.

  12. Korean nurses' ethical dilemmas, professional values and professional quality of life.

    PubMed

    Kim, Kyunghee; Han, Yonghee; Kim, Ji-su

    2015-06-01

    In the changing medical environment, professional stress continuously increases as the individual's quality of life suffers. Of all the healthcare professions, nursing is especially prone to burnout, compassion fatigue and reduced compassion satisfaction, due to the tensions resulting from the physical and psychological stress of caring for extremely ill patients. This study examined the professional quality of life of clinical nurses in Korea and the relationship between their experiences in ethical dilemmas and professional values. This was a cross-sectional study of a convenience sample consisting of 488 clinical nurses. We used four questionnaires to measure the participants' demographic characteristics, experiences in ethical dilemmas, professional nursing values and professional quality of life (ProQOL assessment, Version 5). Ethical considerations: This study received approval from the Institutional Review Board of Bronco Memorial Hospital. Written informed consent was given by all participants. The nurses' professional quality of life was affected by ethical dilemmas and professional nursing values. The factors influencing compassion satisfaction were age, client domain of ethical dilemmas, social awareness, professionalism of nursing and the roles of nursing services in professional values. The factors influencing burnout were marital status (married), religion (yes), human life domain, professional work domain of ethical dilemmas, social awareness and the role of nursing services in nursing professional values. The factors influencing secondary traumatic stress were human life domain, client domain and the professional work domain of ethical dilemmas. Intervention to help nurses increase their professional quality of life will have a greater chance of success if they are based on the nurses' values and beliefs about the ethical dilemmas they face and foster the establishment of positive professional values. © The Author(s) 2014.

  13. Species Diversity and Functional Prediction of Surface Bacterial Communities on Aging Flue-Cured Tobaccos.

    PubMed

    Wang, Fan; Zhao, Hongwei; Xiang, Haiying; Wu, Lijun; Men, Xiao; Qi, Chang; Chen, Guoqiang; Zhang, Haibo; Wang, Yi; Xian, Mo

    2018-06-05

    Microbes on aging flue-cured tobaccos (ATFs) improve the aroma and other qualities desirable in products. Understanding the relevant organisms would picture microbial community diversity, metabolic potential, and their applications. However, limited efforts have been made on characterizing the microbial quality and functional profiling. Herein, we present our investigation of the bacterial diversity and predicted potential genetic capability of the bacteria from two AFTs using 16S rRNA gene sequences and phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) software. The results show that dominant bacteria from AFT surfaces were classified into 48 genera, 36 families, and 7 phyla. In addition, Bacillus spp. was found prevalent on both ATFs. Furthermore, PICRUSt predictions of bacterial community functions revealed many attractive metabolic capacities in the AFT microbiota, including several involved in the biosynthesis of flavors and fragrances and the degradation of harmful compounds, such as nicotine and nitrite. These results provide insights into the importance of AFT bacteria in determining product qualities and indicate specific microbial species with predicted enzymatic capabilities for the production of high-efficiency flavors, the degradation of undesirable compounds, and the provision of nicotine and nitrite tolerance which suggest fruitful areas of investigation into the manipulation of AFT microbiota for AFT and other product improvements.

  14. Dilemmas and Discarded Leadership

    ERIC Educational Resources Information Center

    Dana, Joyce A.

    2009-01-01

    Women are challenged most by cultural norms, particularly sex-role norms, religious and political ideologies, and gender-structured opportunities that favor men. Although some stereotypes have loosened a bit, dilemmas remain for women who aspire to fill school district leadership positions. The author's predicament is not unique. It is something…

  15. Ethical Dilemmas as Perceived by Healthcare Students with Teaching Implications

    ERIC Educational Resources Information Center

    Buelow, Janet R.; Mahan, Pamela L.; Garrity, April W.

    2010-01-01

    Ethical dilemmas are experienced by all individuals, but are especially prevalent among healthcare professionals. Universities and colleges preparing students to work and provide care in this arena are currently addressing this challenge through traditional ethics courses and lectures. However, student perspectives of the major ethical dilemmas in…

  16. School District Superintendents' Response to Ethical Dilemmas: A Grounded Theory

    ERIC Educational Resources Information Center

    Sprouse, Fay Simpson

    2009-01-01

    Ethical dilemmas, situations involving a conflict between values or principles, often arise when employees of school districts violate laws or professional codes of behavior. Ethical dilemmas also occur when there are inequities in educational programming, resulting in missed opportunities for students. This qualitative study, conducted with the…

  17. Jellyfish modulate bacterial dynamic and community structure.

    PubMed

    Tinta, Tinkara; Kogovšek, Tjaša; Malej, Alenka; Turk, Valentina

    2012-01-01

    Jellyfish blooms have increased in coastal areas around the world and the outbreaks have become longer and more frequent over the past few decades. The Mediterranean Sea is among the heavily affected regions and the common bloom-forming taxa are scyphozoans Aurelia aurita s.l., Pelagia noctiluca, and Rhizostoma pulmo. Jellyfish have few natural predators, therefore their carcasses at the termination of a bloom represent an organic-rich substrate that supports rapid bacterial growth, and may have a large impact on the surrounding environment. The focus of this study was to explore whether jellyfish substrate have an impact on bacterial community phylotype selection. We conducted in situ jellyfish-enrichment experiment with three different jellyfish species. Bacterial dynamic together with nutrients were monitored to assess decaying jellyfish-bacteria dynamics. Our results show that jellyfish biomass is characterized by protein rich organic matter, which is highly bioavailable to 'jellyfish-associated' and 'free-living' bacteria, and triggers rapid shifts in bacterial population dynamics and composition. Based on 16S rRNA clone libraries and denaturing gradient gel electrophoresis (DGGE) analysis, we observed a rapid shift in community composition from unculturable Alphaproteobacteria to culturable species of Gammaproteobacteria and Flavobacteria. The results of sequence analyses of bacterial isolates and of total bacterial community determined by culture independent genetic analysis showed the dominance of the Pseudoalteromonadaceae and the Vibrionaceae families. Elevated levels of dissolved proteins, dissolved organic and inorganic nutrient release, bacterial abundance and carbon production as well as ammonium concentrations characterized the degradation process. The biochemical composition of jellyfish species may influence changes in the amount of accumulated dissolved organic and inorganic nutrients. Our results can contribute insights into possible changes in

  18. Key determinants of the fungal and bacterial microbiomes in homes.

    PubMed

    Kettleson, Eric M; Adhikari, Atin; Vesper, Stephen; Coombs, Kanistha; Indugula, Reshmi; Reponen, Tiina

    2015-04-01

    The microbiome of the home is of great interest because of its possible impact on health. Our goal was to identify some of the factors that determine the richness, evenness and diversity of the home's fungal and bacterial microbiomes. Vacuumed settled dust from homes (n=35) in Cincinnati, OH, were analyzed by pyrosequencing to determine the fungal and bacterial relative sequence occurrence. The correlation coefficients between home environmental characteristics, including age of home, Environmental Relative Moldiness Index (ERMI) values, occupant number, relative humidity and temperature, as well as pets (dog and cat) were evaluated for their influence on fungal and bacterial communities. In addition, linear discriminant analysis (LDA) was used for identifying fungal and bacterial genera and species associated with those housing determinants found to be significant. The fungal richness was found to be positively correlated with age of home (p=0.002), ERMI value (p=0.003), and relative humidity (p=0.015) in the home. However, fungal evenness and diversity were only correlated with the age of home (p=0.001). Diversity and evenness (not richness) of the bacterial microbiome in the homes were associated with dog ownership. Linear discriminant analysis showed total of 39 putative fungal genera/species with significantly higher LDA scores in high ERMI homes and 47 genera/species with significantly higher LDA scores in homes with high relative humidity. When categorized according to the age of the home, a total of 67 fungal genera/species had LDA scores above the significance threshold. Dog ownership appeared to have the most influence on the bacterial microbiome, since a total of 130 bacterial genera/species had significantly higher LDA scores in homes with dogs. Some key determinants of the fungal and bacterial microbiome appear to be excess moisture, age of the home and dog ownership. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Broad spectrum microarray for fingerprint-based bacterial species identification

    PubMed Central

    2010-01-01

    Background Microarrays are powerful tools for DNA-based molecular diagnostics and identification of pathogens. Most target a limited range of organisms and are based on only one or a very few genes for specific identification. Such microarrays are limited to organisms for which specific probes are available, and often have difficulty discriminating closely related taxa. We have developed an alternative broad-spectrum microarray that employs hybridisation fingerprints generated by high-density anonymous markers distributed over the entire genome for identification based on comparison to a reference database. Results A high-density microarray carrying 95,000 unique 13-mer probes was designed. Optimized methods were developed to deliver reproducible hybridisation patterns that enabled confident discrimination of bacteria at the species, subspecies, and strain levels. High correlation coefficients were achieved between replicates. A sub-selection of 12,071 probes, determined by ANOVA and class prediction analysis, enabled the discrimination of all samples in our panel. Mismatch probe hybridisation was observed but was found to have no effect on the discriminatory capacity of our system. Conclusions These results indicate the potential of our genome chip for reliable identification of a wide range of bacterial taxa at the subspecies level without laborious prior sequencing and probe design. With its high resolution capacity, our proof-of-principle chip demonstrates great potential as a tool for molecular diagnostics of broad taxonomic groups. PMID:20163710

  20. Research Dilemmas with Behavioral Big Data.

    PubMed

    Shmueli, Galit

    2017-06-01

    Behavioral big data (BBD) refers to very large and rich multidimensional data sets on human and social behaviors, actions, and interactions, which have become available to companies, governments, and researchers. A growing number of researchers in social science and management fields acquire and analyze BBD for the purpose of extracting knowledge and scientific discoveries. However, the relationships between the researcher, data, subjects, and research questions differ in the BBD context compared to traditional behavioral data. Behavioral researchers using BBD face not only methodological and technical challenges but also ethical and moral dilemmas. In this article, we discuss several dilemmas, challenges, and trade-offs related to acquiring and analyzing BBD for causal behavioral research.

  1. Ethical Dilemmas in Qualitative Research Methodology: Researcher's Reflections

    ERIC Educational Resources Information Center

    Ngozwana, Nomazulu

    2018-01-01

    This article examines the ethical dilemmas that are specific to qualitative research methodology. These dilemmas concern the issues of withdrawal from the study, anonymity and confidentiality, which are discussed. Each aspect examines how it was dealt with using the researcher's reflections. The research was positioned within an interpretive…

  2. Designing and Introducing Ethical Dilemmas into Computer-Based Business Simulations

    ERIC Educational Resources Information Center

    Schumann, Paul L.; Scott, Timothy W.; Anderson, Philip H.

    2006-01-01

    This article makes two contributions to the teaching of business ethics literature. First, it describes the steps involved in developing effective ethical dilemmas to incorporate into a computer-based business simulation. Second, it illustrates these steps by presenting two ethical dilemmas that an instructor can incorporate into any business…

  3. Gamma-irradiated bacterial preparation having anti-tumor activity

    DOEpatents

    Vass, Arpad A.; Tyndall, Richard L.; Terzaghi-Howe, Peggy

    1999-01-01

    A bacterial preparation from Pseudomonas species isolated #15 ATCC 55638 that has been exposed to gamma radiation exhibits cytotoxicity that is specific for neoplastic carcinoma cells. A method for obtaining a bacterial preparation having antitumor activity consists of suspending a bacterial isolate in media and exposing the suspension to gamma radiation. A bacterial preparation of an aged culture of an amoeba-associated bacteria exhibits anti-reverse transcriptase activity. A method for obtaining a bacterial preparation having anti-reverse transcriptase activity from an amoeba-associated bacterial isolate grown to stationary phase is disclosed.

  4. The Dilemmas of Teaching Reading. Eighth Yearbook of The American Reading Forum, 1988.

    ERIC Educational Resources Information Center

    Lumpkin, Donavon, Ed.; And Others

    Articles in this eighth yearbook of the American Reading Forum address the dilemmas of teaching reading. Articles, listed with their authors, are as follows: (1) "Deepening a Dilemma: Stylus vs. Computer Writing at an Early Primary Level" (J. Heep); (2) "Concept Maps and Vee Diagrams: Strategies To Deal with the Dilemma of the Restricted…

  5. Would they dope? Revisiting the Goldman dilemma.

    PubMed

    Connor, James; Woolf, Jules; Mazanov, Jason

    2013-07-01

    Discussions of doping often report Goldman's sensational results that half of the elite athletes asked would take a drug that guaranteed sporting success which would also result in their death in 5 years' time. There has never been any effort to assess the properties of the 'Goldman dilemma' or replicate the results in the post World Anti-Doping Agency context. This research evaluated the dilemma with contemporary elite athletes. Participants at an elite-level track and field meet in North America were segregated into an interview or online response. After basic demographics, participants were presented with three variant 'Goldman' dilemmas counter-balanced for presentation order. Only 2 out of 212 samples  (119 men, 93 women, mean age 20.89) reported that they would take the Faustian bargain offered by the original Goldman dilemma. However, if there were no consequences to the (illegal) drug use, then 25/212 indicated that they would take the substance (no death condition). Legality also changes the acceptance rate to 13/212 even with death as a consequence. Regression modelling showed that no other variable was significant (gender, competitive level, type of sport) and there was no statistical difference between the interview and online collection method. Goldman's results do not match our sample. A subset of athletes is willing to dope and another subset is willing to sacrifice their life to achieve success, although to a much lesser degree than that observed by Goldman. A larger scale online survey is now viable to answer important questions such as variation across sports.

  6. Molecular Survey of Bacterial Communities Associated with Bacterial Chondronecrosis with Osteomyelitis (BCO) in Broilers

    PubMed Central

    Jiang, Tieshan; Mandal, Rabindra K.; Wideman, Robert F.; Khatiwara, Anita; Pevzner, Igal; Min Kwon, Young

    2015-01-01

    Bacterial chondronecrosis with osteomyelitis (BCO) is recognized as an important cause of lameness in commercial broiler chickens (meat-type chickens). Relatively little is known about the microbial communities associated with BCO. This study was conducted to increase our understanding of the microbial factors associated with BCO using a culture-independent approach. Using Illumina sequencing of the hyper-variable region V6 in the 16S rRNA gene, we characterized the bacterial communities in 97 femoral or tibial heads from normal and lame broilers carefully selected to represent diverse variations in age, line, lesion type, floor type, clinical status and bone type. Our in-depth survey based on 14 million assembled sequence reads revealed that complex bacterial communities exist in all samples, including macroscopically normal bones from clinically healthy birds. Overall, Proteobacteria (mean 90.9%) comprised the most common phylum, followed by Firmicutes (6.1%) and Actinobacteria (2.6%), accounting for more than 99% of all reads. Statistical analyses demonstrated that there are differences in bacterial communities in different types of bones (femur vs. tibia), lesion types (macroscopically normal femora or tibiae vs. those with pathognomonic BCO lesions), and among individual birds. This analysis also showed that BCO samples overrepresented genera Staphylococcus, whose species have been frequently isolated in BCO samples in previous studies. Rarefaction analysis demonstrated the general tendency that increased severities of BCO lesions were associated with reduced species diversity in both femoral and tibial samples when compared to macroscopically normal samples. These observations suggest that certain bacterial subgroups are preferentially selected in association with the development of BCO lesions. Understanding the microbial species associated with BCO will identify opportunities for understanding and modulating the pathogenesis of this form of lameness in

  7. Dancing for Food in the Deep Sea: Bacterial Farming by a New Species of Yeti Crab

    PubMed Central

    Thurber, Andrew R.; Jones, William J.; Schnabel, Kareen

    2011-01-01

    Vent and seep animals harness chemosynthetic energy to thrive far from the sun's energy. While symbiont-derived energy fuels many taxa, vent crustaceans have remained an enigma; these shrimps, crabs, and barnacles possess a phylogenetically distinct group of chemosynthetic bacterial epibionts, yet the role of these bacteria has remained unclear. We test whether a new species of Yeti crab, which we describe as Kiwa puravida n. sp, farms the epibiotic bacteria that it grows on its chelipeds (claws), chelipeds that the crab waves in fluid escaping from a deep-sea methane seep. Lipid and isotope analyses provide evidence that epibiotic bacteria are the crab's main food source and K. puravida n. sp. has highly-modified setae (hairs) on its 3rd maxilliped (a mouth appendage) which it uses to harvest these bacteria. The ε- and γ- proteobacteria that this methane-seep species farms are closely related to hydrothermal-vent decapod epibionts. We hypothesize that this species waves its arm in reducing fluid to increase the productivity of its epibionts by removing boundary layers which may otherwise limit carbon fixation. The discovery of this new species, only the second within a family described in 2005, stresses how much remains undiscovered on our continental margins. PMID:22140426

  8. Dancing for food in the deep sea: bacterial farming by a new species of Yeti crab.

    PubMed

    Thurber, Andrew R; Jones, William J; Schnabel, Kareen

    2011-01-01

    Vent and seep animals harness chemosynthetic energy to thrive far from the sun's energy. While symbiont-derived energy fuels many taxa, vent crustaceans have remained an enigma; these shrimps, crabs, and barnacles possess a phylogenetically distinct group of chemosynthetic bacterial epibionts, yet the role of these bacteria has remained unclear. We test whether a new species of Yeti crab, which we describe as Kiwa puravida n. sp, farms the epibiotic bacteria that it grows on its chelipeds (claws), chelipeds that the crab waves in fluid escaping from a deep-sea methane seep. Lipid and isotope analyses provide evidence that epibiotic bacteria are the crab's main food source and K. puravida n. sp. has highly-modified setae (hairs) on its 3(rd) maxilliped (a mouth appendage) which it uses to harvest these bacteria. The ε- and γ- proteobacteria that this methane-seep species farms are closely related to hydrothermal-vent decapod epibionts. We hypothesize that this species waves its arm in reducing fluid to increase the productivity of its epibionts by removing boundary layers which may otherwise limit carbon fixation. The discovery of this new species, only the second within a family described in 2005, stresses how much remains undiscovered on our continental margins.

  9. Ethical dilemmas concerning decision-making within health care leadership: a systematic literature review.

    PubMed

    Zydziūnaite, Vilma; Suominen, Tarja; Astedt-Kurki, Päivi; Lepaite, Daiva

    2010-01-01

    The objective was to describe the research methods and research focuses on ethical dilemmas concerning decision-making within health care leadership. The search was conducted on Medline and PubMed databases (1998-2008). The systematic review included 21 selected articles. The ethical dilemmas concerning decision-making within health care leadership are related to three levels: institutional (particular organization), political and local interface (local governmental structure), and national (professional expertise and system). The terms that are used as adequate to the term of "ethical dilemma" are the following: "continuous balancing," "result of resource allocation," "gap between professional obligations and possibilities," "ethically controversial situation," "concern about interactions," "ethical difficulty," "outcome of medical choices," "concern about society access to health care resources," "ethically difficult/challenging situation," "(the consequence of) ethical concern/ethical issue." In qualitative studies, a semi-structured interview and qualitative content analysis are the most commonly applied methods; in quantitative studies, questionnaire surveys are employed. In the research literature, there is a lack of specification according to professional qualification of health care professionals concerning ethical dilemmas by decision-making within health care management/administration. The research on ethical dilemmas in health care leadership, management, and administration should integrate data about levels at which ethical dilemmas occur and investigate ethical dilemmas as complex phenomena because those are attached to decision-making and specific nuances of health care management/administration. In this article, the presented scientific problem requires extensive scientific discussions and research on ethical dilemmas concerning decision-making within health care leadership at various levels.

  10. A national survey of U.S. internists' experiences with ethical dilemmas and ethics consultation.

    PubMed

    DuVal, Gordon; Clarridge, Brian; Gensler, Gary; Danis, Marion

    2004-03-01

    To identify the ethical dilemmas that internists encounter, the strategies they use to address them, and the usefulness of ethics consultation. National telephone survey. Doctors' offices. General internists, oncologists, and critical care/pulmonologists (N = 344, 64% response rate). Types of ethical dilemmas recently encountered and likelihood of requesting ethics consultation; satisfaction with resolution of ethical dilemmas with and without ethics consultation. Internists most commonly reported dilemmas regarding end-of-life decision making, patient autonomy, justice, and conflict resolution. General internists, oncologists, and critical care specialists reported participating in an average of 1.4, 1.3, and 4.1 consultations in the preceding 2 years, respectively (P <.0001). Physicians with the least ethics training had the least access to and participated in the fewest ethics consultations; 19% reported consultation was unavailable at their predominant practice site. Dilemmas about end-of-life decisions and patient autonomy were often referred for consultation, while dilemmas about justice, such as lack of insurance or limited resources, were rarely referred. While most physicians thought consultations yielded information that would be useful in dealing with future ethical dilemmas (72%), some hesitated to seek ethics consultation because they believed it was too time consuming (29%), might make the situation worse (15%), or that consultants were unqualified (11%). While most internists recall recent ethical dilemmas in their practices, those with the least preparation and experience have the least access to ethics consultation. Health care organizations should emphasize ethics educational activities to prepare physicians for handling ethical dilemmas on their own and should improve the accessibility and responsiveness of ethics consultation when needed.

  11. Relationship between bacterial diversity and environmental parameters during composting of different raw materials.

    PubMed

    Wang, Xueqin; Cui, Hongyang; Shi, Jianhong; Zhao, Xinyu; Zhao, Yue; Wei, Zimin

    2015-12-01

    The aim of this study was to compare the bacterial structure of seven different composts. The primary environmental factors affecting bacterial species were identified, and a strategy to enhance the abundance of uncultured bacteria through controlling relevant environmental parameters was proposed. The results showed that the physical-chemical parameters of each different pile changed in its own manner during composting, which affected the structure and succession of bacteria in different ways. DGGE profiles showed that there were 10 prominent species during composting. Among them, four species existed in all compost types, two species existed in several piles and four species were detected in a single material. Redundancy analysis results showed that bacterial species compositions were significantly influenced by C/N and moisture (p<0.05). The optimal range of C/N was 14-27. Based on these results, the primary environmental factors affecting a certain species were further identified as a potential control of bacterial diversity. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. RNA-oligonucleotide quantification technique (ROQT) for the enumeration of uncultivated bacterial species in subgingival biofilms

    PubMed Central

    Teles, F.R.F.; Teles, R.P.; Siegelin, Y.; Paster, B.; Haffajee, A.D.; Socransky, S.S.

    2010-01-01

    SUMMARY Approximately 35% of the species present in subgingival biofilms are as yet uncultivated, so their role in periodontal pathogenesis is unknown. The aim of the present study was to develop a high throughput method to quantify a wide range of cultivated and uncultivated taxa in subgingival biofilm samples associated with periodontal disease or health. Oligonucleotides targeting the 16S ribosomal DNA gene were designed, synthesized and labeled with digoxigenin. These probes were hybridized with the total nucleic acids of pure cultures or subgingival biofilm samples. Target species included cultivated taxa associated with periodontal health and disease, as well as uncultivated species, such as TM7 sp OT 346, Mitsuokella sp. OT 131 and Desulfobulbus sp. OT 041. Sensitivity and specificity of the probes were determined. A Universal probe was used to assess total bacterial load. Sequences complementary to the probes were used as standards for quantification. Chemiluminescent signals were visualized after film exposure or using a CCD camera. In a pilot clinical study, 266 subgingival plaque samples from eight periodontally healthy people and 11 patients with periodontitis were examined. Probes were specific and sensitivity reached 104 cells. Fusobacterium nucleatum ss polymorphum and Actinomyces gerencseriae were the most abundant cultivated taxa in clinical samples. Among uncultivated/unrecognized species, Mitsuokella sp. OT 131 and Prevotella sp. OT 306 were the most numerous. Porphyromonas gingivalis and Desulfobulbus sp. OT 041 were only detected in patients with periodontitis. Direct hybridization of total nucleic acids using oligonucleotide probes permitted the quantification of multiple cultivated and uncultivated taxa in mixed species biofilm samples. PMID:21375703

  13. RT-PCR-DGGE Analysis to Elucidate the Dominant Bacterial Species of Industrial Spanish-Style Green Table Olive Fermentations.

    PubMed

    Benítez-Cabello, Antonio; Bautista-Gallego, Joaquín; Garrido-Fernández, Antonio; Rantsiou, Kalliopi; Cocolin, Luca; Jiménez-Díaz, Rufino; Arroyo-López, Francisco N

    2016-01-01

    This paper describes the dominant bacterial species metabolically active through the industrial production of Spanish-style Manzanilla and Gordal olives. For this purpose, samples (brines and fruits) obtained at 0, 15, and 90 fermentation days were analyzed by a culture-independent approach to determine viable cells by reverse transcription of RNA and further PCR-DGGE analysis, detecting at least 7 different species. Vibrio vulnificus, Lactobacillus plantarum group, and Lactobacillus parafarraginis were present in samples from both cultivars; Lactobacillus sanfranciscensis and Halolactobacillus halophilus were detected only in Gordal samples, while Staphylococcus sp. was exclusively found at the onset of Manzanilla fermentations. Physicochemical data showed a typical fermentation profile while scanning electron microscopy confirmed the in situ biofilm formation on the olive epidermis. Different Bacillus, Staphylococcus, and Enterococcus species, not detected during the fermentation process, were also found in the solid marine salt used by the industry for preparation of brines. Elucidation of these non-lactic acid bacteria species role during fermentation is then an appealingly challenge, particularly regarding safety issues.

  14. Review: Game theory of public goods in one-shot social dilemmas without assortment.

    PubMed

    Archetti, Marco; Scheuring, István

    2012-04-21

    We review the theory of public goods in biology. In the N-person prisoner's dilemma, where the public good is a linear function of the individual contributions, cooperation requires some form of assortment, for example due to kin discrimination, population viscosity or repeated interactions. In most social species ranging from bacteria to humans, however, public goods are usually a non-linear function of the contributions, which makes cooperation possible without assortment. More specifically, a polymorphic state can be stable in which cooperators and non-cooperators coexist. The existence of mixed equilibria in public goods games is a fundamental result in the study of cooperation that has been overlooked so far, because of the disproportionate attention given to the two- and N-person prisoner's dilemma. Methods and results from games with pairwise interactions or linear benefits cannot, in general, be extended to the analysis of public goods. Game theory helps explain the production of public goods in one-shot, N-person interactions without assortment, it leads to predictions that can be easily tested and allows a prescriptive approach to cooperation. Copyright © 2011 Elsevier Ltd. All rights reserved.

  15. Juan's Dilemma: A New Twist on the Old Lemon Battery

    ERIC Educational Resources Information Center

    Hunt, Vanessa; Sorey, Timothy; Balandova, Evguenia; Palmquist, Bruce

    2010-01-01

    When life hands you lemons, make a battery! In this article, the authors describe an activity they refer to as "Juan's Dilemma," an extension of the familiar lemon-battery activity (Goodisman 2001). Juan's Dilemma integrates oxidation and reduction chemistry with circuit theory in a fun, real-world exercise. The authors designed this activity for…

  16. Promiscuity in mice is associated with increased vaginal bacterial diversity

    NASA Astrophysics Data System (ADS)

    Macmanes, Matthew David

    2011-11-01

    Differences in the number of sexual partners (i.e., mating system) have the potential to exert a strong influence on the bacterial communities present in reproductive structures like the vagina. Because this structure serves as a conduit for gametes, bacteria present there may have a pronounced, direct effect on host reproductive success. As a first step towards the identification of the relationship between sexual behavior and potentially pathogenic bacterial communities inhabiting vital reproductive structures, as well as their potential effects on fitness, I sought to quantify differences in bacterial diversity in a promiscuous and monogamous mammal species. To accomplish this, I used two sympatric species of Peromyscus rodents— Peromyscus californicus and Peromyscus maniculatus that differ with regard to the number of sexual partners per individual to test the hypothesis that bacterial diversity should be greater in the promiscuous P. maniculatus relative to the monogamous P. californicus. As predicted, phylogenetically controlled and operational taxonomic unit-based indices of bacterial diversity indicated that diversity is greater in the promiscuous species. These results provide important new insights into the effects of mating system on bacterial diversity in free-living vertebrates, and may suggest a potential cost of promiscuity.

  17. A National Survey of U.S. Internists’ Experiences with Ethical Dilemmas and Ethics Consultation

    PubMed Central

    DuVal, Gordon; Clarridge, Brian; Gensler, Gary; Danis, Marion

    2004-01-01

    OBJECTIVE To identify the ethical dilemmas that internists encounter, the strategies they use to address them, and the usefulness of ethics consultation. DESIGN National telephone survey. SETTING Doctors’ offices. PARTICIPANTS General internists, oncologists, and critical care/pulmonologists (N = 344, 64% response rate). MEASUREMENTS Types of ethical dilemmas recently encountered and likelihood of requesting ethics consultation; satisfaction with resolution of ethical dilemmas with and without ethics consultation. RESULTS Internists most commonly reported dilemmas regarding end-of-life decision making, patient autonomy, justice, and conflict resolution. General internists, oncologists, and critical care specialists reported participating in an average of 1.4, 1.3, and 4.1 consultations in the preceding 2 years, respectively (P < .0001). Physicians with the least ethics training had the least access to and participated in the fewest ethics consultations; 19% reported consultation was unavailable at their predominant practice site. Dilemmas about end-of-life decisions and patient autonomy were often referred for consultation, while dilemmas about justice, such as lack of insurance or limited resources, were rarely referred. While most physicians thought consultations yielded information that would be useful in dealing with future ethical dilemmas (72%), some hesitated to seek ethics consultation because they believed it was too time consuming (29%), might make the situation worse (15%), or that consultants were unqualified (11%). CONCLUSIONS While most internists recall recent ethical dilemmas in their practices, those with the least preparation and experience have the least access to ethics consultation. Health care organizations should emphasize ethics educational activities to prepare physicians for handling ethical dilemmas on their own and should improve the accessibility and responsiveness of ethics consultation when needed. PMID:15009780

  18. Gamma-irradiated bacterial preparation having anti-tumor activity

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Vass, A.A.; Tyndall, R.L.; Terzaghi-Howe, P.

    1999-11-16

    This application describes a bacterial preparation from Pseudomonas species isolated {number{underscore}sign}15 ATCC 55638 that has been exposed to gamma radiation exhibits cytotoxicity that is specific for neoplastic carcinoma cells. A method for obtaining a bacterial preparation having antitumor activity consists of suspending a bacterial isolate in media and exposing the suspension to gamma radiation. A bacterial preparation of an aged culture of an amoeba-associated bacteria exhibits anti-reverse transcriptase activity. A method for obtaining a bacterial preparation having anti-reverse transcriptase activity from an amoeba-associated bacterial isolate grown to stationary phase is disclosed.

  19. Ethical dilemmas encountered by small animal veterinarians: characterisation, responses, consequences and beliefs regarding euthanasia.

    PubMed

    Kipperman, Barry; Morris, Patricia; Rollin, Bernard

    2018-05-12

    Small animal veterinarians' opinions were investigated regarding the frequency and nature of ethical dilemmas encountered, beliefs regarding euthanasia and balancing client and animal interests, prevalence and value of ethics training and proposals to mitigate the stressful effects of ethical dilemmas. The majority (52 per cent) of 484 respondents in the USA indicated via an online survey experiencing an ethical dilemma regarding the interests of clients and those of their patients at least weekly. Scenarios involving client financial concerns were commonly reported causes of ethical conflicts. While only 20 per cent of respondents indicated that other practitioners prioritise patient interests, 50 per cent of respondents characterised their own behaviour as prioritising patients. Most respondents (52 per cent) reported that ethical dilemmas are the leading cause, or are one of many equal causes, of work-related stress. Less experienced practitioners, general practitioners and associate veterinarians were more likely to encounter situations they defined as ethical dilemmas, and female respondents were more likely to find ethical dilemmas stressful. Most small animal veterinarians experience ethical dilemmas regularly, which contribute to moral stress. Results suggested that most small animal practitioners believe that greater awareness of moral stress and providing training in ethical theories and tools for coping with ethical dilemmas can ameliorate moral stress. © British Veterinary Association (unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  20. Detection of bacterial pathogens including potential new species in human head lice from Mali.

    PubMed

    Amanzougaghene, Nadia; Fenollar, Florence; Sangaré, Abdoul Karim; Sissoko, Mahamadou S; Doumbo, Ogobara K; Raoult, Didier; Mediannikov, Oleg

    2017-01-01

    In poor African countries, where no medical and biological facilities are available, the identification of potential emerging pathogens of concern at an early stage is challenging. Head lice, Pediculus humanus capitis, have a short life, feed only on human blood and do not transmit pathogens to their progeny. They are, therefore, a perfect tool for the xenodiagnosis of current or recent human infection. This study assessed the occurrence of bacterial pathogens from head lice collected in two rural villages from Mali, where a high frequency of head lice infestation had previously been reported, using molecular methods. Results show that all 600 head lice, collected from 117 individuals, belonged to clade E, specific to West Africa. Bartonella quintana, the causative agent of trench fever, was identified in three of the 600 (0.5%) head lice studied. Our study also shows, for the first time, the presence of the DNA of two pathogenic bacteria, namely Coxiella burnetii (5.1%) and Rickettsia aeschlimannii (0.6%), detected in human head lice, as well as the DNA of potential new species from the Anaplasma and Ehrlichia genera of unknown pathogenicity. The finding of several Malian head lice infected with B. quintana, C. burnetii, R. aeschlimannii, Anaplasma and Ehrlichia is alarming and highlights the need for active survey programs to define the public health consequences of the detection of these emerging bacterial pathogens in human head lice.

  1. Real-Life Dilemma Resolution among Malaysian Adolescents: A Case Study

    ERIC Educational Resources Information Center

    Balakrishnan, Vishalache

    2011-01-01

    This paper is based on a participatory action research. The research is based on a process of resolving real-life moral dilemmas in the Moral Education classroom. It critically analyses the types of real-life moral dilemmas that a selected group of secondary students thought about. It also indicates the moral choices that they make based on their…

  2. Cooperation and control in multiplayer social dilemmas

    PubMed Central

    Hilbe, Christian; Wu, Bin; Traulsen, Arne; Nowak, Martin A.

    2014-01-01

    Direct reciprocity and conditional cooperation are important mechanisms to prevent free riding in social dilemmas. However, in large groups, these mechanisms may become ineffective because they require single individuals to have a substantial influence on their peers. However, the recent discovery of zero-determinant strategies in the iterated prisoner’s dilemma suggests that we may have underestimated the degree of control that a single player can exert. Here, we develop a theory for zero-determinant strategies for iterated multiplayer social dilemmas, with any number of involved players. We distinguish several particularly interesting subclasses of strategies: fair strategies ensure that the own payoff matches the average payoff of the group; extortionate strategies allow a player to perform above average; and generous strategies let a player perform below average. We use this theory to describe strategies that sustain cooperation, including generalized variants of Tit-for-Tat and Win-Stay Lose-Shift. Moreover, we explore two models that show how individuals can further enhance their strategic options by coordinating their play with others. Our results highlight the importance of individual control and coordination to succeed in large groups. PMID:25349400

  3. [Ethical Dilemmas in Practice of Medicine Child].

    PubMed

    Ruiz López, Justo; Navarro Zaragoza, Javier; Carrillo Navarro, Francisco; Luna Maldonado, Aurelio

    2017-01-01

    After reviewing the existing bibliography in the last 20 years, we concluded that there is a lack of information regarding the ethical conflicts that affect to pediatrics in their daily practice. It produces certain degree of uncertainty in these professionals at the time of solving these problems. We made a systematic search in the main data bases, finding more than 150 articles related, of which 80 were considered outstanding. After studying them, we have found 40 ethical dilemmas, related to some principle of solution and that we described in this article. Through them we can find such important dilemmas as those related to physical disability, palliative care or consent from children.

  4. Evolution of Cooperation in Social Dilemmas on Complex Networks

    PubMed Central

    Iyer, Swami; Killingback, Timothy

    2016-01-01

    Cooperation in social dilemmas is essential for the functioning of systems at multiple levels of complexity, from the simplest biological organisms to the most sophisticated human societies. Cooperation, although widespread, is fundamentally challenging to explain evolutionarily, since natural selection typically favors selfish behavior which is not socially optimal. Here we study the evolution of cooperation in three exemplars of key social dilemmas, representing the prisoner’s dilemma, hawk-dove and coordination classes of games, in structured populations defined by complex networks. Using individual-based simulations of the games on model and empirical networks, we give a detailed comparative study of the effects of the structural properties of a network, such as its average degree, variance in degree distribution, clustering coefficient, and assortativity coefficient, on the promotion of cooperative behavior in all three classes of games. PMID:26928428

  5. Bacterial detection: from microscope to smartphone.

    PubMed

    Gopinath, Subash C B; Tang, Thean-Hock; Chen, Yeng; Citartan, Marimuthu; Lakshmipriya, Thangavel

    2014-10-15

    The ubiquitous nature of bacteria enables them to survive in a wide variety of environments. Hence, the rise of various pathogenic species that are harmful to human health raises the need for the development of accurate sensing systems. Sensing systems are necessary for diagnosis and epidemiological control of pathogenic organism, especially in the food-borne pathogen and sanitary water treatment facility' bacterial populations. Bacterial sensing for the purpose of diagnosis can function in three ways: bacterial morphological visualization, specific detection of bacterial component and whole cell detection. This paper provides an overview of the currently available bacterial detection systems that ranges from microscopic observation to state-of-the-art smartphone-based detection. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. [Sharing bacterial microbiota between owners and their pets (dogs, cats)].

    PubMed

    Wipler, Jan; Čermáková, Zuzana; Hanzálek, Tomáš; Horáková, Hana; Žemličková, Helena

    2017-06-01

    The microbiological aspect of a relationship between pets (dogs/cats) and their owners is mainly concerned with the incidence of shared bacterial species, in particular potential pathogens. Given the great popularity of sharing homes with pets (dogs/cats) in the Czech Republic, there is an increased possibility of communication between microbiota of the two macroorganisms (pet and owner). The aim of the study was to determine the biodiversity of shared bacteria and possibility of exchange of genes of resistance to antimicrobial agents between potential pathogens based on the close relationship between pets and humans. A total of 103 samples were collected from 20 pairs (20 owners, 16 dogs and 4 cats). All owners completed a questionnaire with their pets' veterinarians. In owners, swabs were collected from the nasal mucosa, armpit and interdigital spaces of the foot. In pets, swabs were obtained from the external auditory meatus and nasal mucosa. In individuals with skin lesions, samples were also collected from the affected areas. Bacterial species were identified by culture and matrix-assisted laser desorption/ionization - time of flight (MALDI-TOF) mass spectrometry. In shared species, susceptibility to antibiotics was tested by the disk diffusion method. Statistical methods were used to correlate the closeness of relationship with the number of shared bacterial species and to correlate previous antimicrobial therapy with shared resistance of the common bacteria. Analysis of the questionnaires showed that 65 % of owners who participated in the study kept more pets at home than only the tested one. In the previous year, 5 % of pets and 5 % of owners received antimicrobial therapy. As many as 45 % of dogs or cats slept in their owners' beds and 80 % rested on a sofa together with their owners. Also, 45 % owners had their faces licked by pets. Eighty percent of pets were fed with several types of food (dry food and cooked food). Further, 70 % of pets lived

  7. Humans choose representatives who enforce cooperation in social dilemmas through extortion

    PubMed Central

    Milinski, Manfred; Hilbe, Christian; Semmann, Dirk; Sommerfeld, Ralf; Marotzke, Jochem

    2016-01-01

    Social dilemmas force players to balance between personal and collective gain. In many dilemmas, such as elected governments negotiating climate-change mitigation measures, the decisions are made not by individual players but by their representatives. However, the behaviour of representatives in social dilemmas has not been investigated experimentally. Here inspired by the negotiations for greenhouse-gas emissions reductions, we experimentally study a collective-risk social dilemma that involves representatives deciding on behalf of their fellow group members. Representatives can be re-elected or voted out after each consecutive collective-risk game. Selfish players are preferentially elected and are hence found most frequently in the ‘representatives' treatment. Across all treatments, we identify the selfish players as extortioners. As predicted by our mathematical model, their steadfast strategies enforce cooperation from fair players who finally compensate almost completely the deficit caused by the extortionate co-players. Everybody gains, but the extortionate representatives and their groups gain the most. PMID:26948250

  8. Humans choose representatives who enforce cooperation in social dilemmas through extortion

    NASA Astrophysics Data System (ADS)

    Milinski, Manfred; Hilbe, Christian; Semmann, Dirk; Sommerfeld, Ralf; Marotzke, Jochem

    2016-03-01

    Social dilemmas force players to balance between personal and collective gain. In many dilemmas, such as elected governments negotiating climate-change mitigation measures, the decisions are made not by individual players but by their representatives. However, the behaviour of representatives in social dilemmas has not been investigated experimentally. Here inspired by the negotiations for greenhouse-gas emissions reductions, we experimentally study a collective-risk social dilemma that involves representatives deciding on behalf of their fellow group members. Representatives can be re-elected or voted out after each consecutive collective-risk game. Selfish players are preferentially elected and are hence found most frequently in the `representatives' treatment. Across all treatments, we identify the selfish players as extortioners. As predicted by our mathematical model, their steadfast strategies enforce cooperation from fair players who finally compensate almost completely the deficit caused by the extortionate co-players. Everybody gains, but the extortionate representatives and their groups gain the most.

  9. New target for inhibition of bacterial RNA polymerase: 'switch region'.

    PubMed

    Srivastava, Aashish; Talaue, Meliza; Liu, Shuang; Degen, David; Ebright, Richard Y; Sineva, Elena; Chakraborty, Anirban; Druzhinin, Sergey Y; Chatterjee, Sujoy; Mukhopadhyay, Jayanta; Ebright, Yon W; Zozula, Alex; Shen, Juan; Sengupta, Sonali; Niedfeldt, Rui Rong; Xin, Cai; Kaneko, Takushi; Irschik, Herbert; Jansen, Rolf; Donadio, Stefano; Connell, Nancy; Ebright, Richard H

    2011-10-01

    A new drug target - the 'switch region' - has been identified within bacterial RNA polymerase (RNAP), the enzyme that mediates bacterial RNA synthesis. The new target serves as the binding site for compounds that inhibit bacterial RNA synthesis and kill bacteria. Since the new target is present in most bacterial species, compounds that bind to the new target are active against a broad spectrum of bacterial species. Since the new target is different from targets of other antibacterial agents, compounds that bind to the new target are not cross-resistant with other antibacterial agents. Four antibiotics that function through the new target have been identified: myxopyronin, corallopyronin, ripostatin, and lipiarmycin. This review summarizes the switch region, switch-region inhibitors, and implications for antibacterial drug discovery. Copyright © 2011 Elsevier Ltd. All rights reserved.

  10. PATRIC: the Comprehensive Bacterial Bioinformatics Resource with a Focus on Human Pathogenic Species ▿ ‡ #

    PubMed Central

    Gillespie, Joseph J.; Wattam, Alice R.; Cammer, Stephen A.; Gabbard, Joseph L.; Shukla, Maulik P.; Dalay, Oral; Driscoll, Timothy; Hix, Deborah; Mane, Shrinivasrao P.; Mao, Chunhong; Nordberg, Eric K.; Scott, Mark; Schulman, Julie R.; Snyder, Eric E.; Sullivan, Daniel E.; Wang, Chunxia; Warren, Andrew; Williams, Kelly P.; Xue, Tian; Seung Yoo, Hyun; Zhang, Chengdong; Zhang, Yan; Will, Rebecca; Kenyon, Ronald W.; Sobral, Bruno W.

    2011-01-01

    Funded by the National Institute of Allergy and Infectious Diseases, the Pathosystems Resource Integration Center (PATRIC) is a genomics-centric relational database and bioinformatics resource designed to assist scientists in infectious-disease research. Specifically, PATRIC provides scientists with (i) a comprehensive bacterial genomics database, (ii) a plethora of associated data relevant to genomic analysis, and (iii) an extensive suite of computational tools and platforms for bioinformatics analysis. While the primary aim of PATRIC is to advance the knowledge underlying the biology of human pathogens, all publicly available genome-scale data for bacteria are compiled and continually updated, thereby enabling comparative analyses to reveal the basis for differences between infectious free-living and commensal species. Herein we summarize the major features available at PATRIC, dividing the resources into two major categories: (i) organisms, genomes, and comparative genomics and (ii) recurrent integration of community-derived associated data. Additionally, we present two experimental designs typical of bacterial genomics research and report on the execution of both projects using only PATRIC data and tools. These applications encompass a broad range of the data and analysis tools available, illustrating practical uses of PATRIC for the biologist. Finally, a summary of PATRIC's outreach activities, collaborative endeavors, and future research directions is provided. PMID:21896772

  11. Chemical sensing in mammalian host-bacterial commensal associations

    USDA-ARS?s Scientific Manuscript database

    The mammalian gastrointestinal (GI) tract is colonized by a complex consortium of bacterial species. Bacteria engage in chemical signaling to coordinate population-wide behavior. However, it is unclear if chemical sensing plays a role in establishing mammalian host–bacterial commensal relationships....

  12. A culture-based study of the bacterial communities within the guts of nine longicorn beetle species and their exo-enzyme producing properties for degrading xylan and pectin.

    PubMed

    Park, Doo-Sang; Oh, Hyun-Woo; Jeong, Won-Jin; Kim, Hyangmi; Park, Ho-Yong; Bae, Kyung Sook

    2007-10-01

    In this study, bacterial communities within the guts of several longicorn beetles were investigated by a culture-dependent method. A total of 142 bacterial strains were isolated from nine species of longicorn beetle, including adults and larvae. A comparison of their partial 16S rRNA gene sequences showed that most of the bacteria constituting the gut communities can typically be found in soil, plants and the intestines of animals, and approximately 10% were proposed as unreported. Phylogenetic analysis demonstrated that the bacterial species comprised 7 phyla, and approximately half were Gammaproteobacteria. Actinobacteria were the second most populous group (19%), followed by Firmicutes (13%) and Alphaproteobacteria (11%). Betaproteobacteria, Flavobacteria, and Acidobacteria were minor constituents. The taxonomic compositions of the isolates were variable according to the species of longicorn beetle. Particularly, an abundance of Actinobacteria existed in Moechotypa diphysis and Mesosa hirsute, which eat broadleaf trees; however, no Actinobacteria were isolated from Corymbia rubra and Monochamus alternatus, which are needle-leaf eaters. Considerable proportions of xylanase and pectinase producing bacteria in the guts of the longicorn beetles implied that the bacteria may play an important role in the digestion of woody diets. Actinobacteria and Gammaproteobacteria were the dominant xylanase producers in the guts of the beetles.

  13. Host-Specificity and Dynamics in Bacterial Communities Associated with Bloom-Forming Freshwater Phytoplankton

    PubMed Central

    Bagatini, Inessa Lacativa; Eiler, Alexander; Bertilsson, Stefan; Klaveness, Dag; Tessarolli, Letícia Piton; Vieira, Armando Augusto Henriques

    2014-01-01

    Many freshwater phytoplankton species have the potential to form transient nuisance blooms that affect water quality and other aquatic biota. Heterotrophic bacteria can influence such blooms via nutrient regeneration but also via antagonism and other biotic interactions. We studied the composition of bacterial communities associated with three bloom-forming freshwater phytoplankton species, the diatom Aulacoseira granulata and the cyanobacteria Microcystis aeruginosa and Cylindrospermopsis raciborskii. Experimental cultures incubated with and without lake bacteria were sampled in three different growth phases and bacterial community composition was assessed by 454-Pyrosequencing of 16S rRNA gene amplicons. Betaproteobacteria were dominant in all cultures inoculated with lake bacteria, but decreased during the experiment. In contrast, Alphaproteobacteria, which made up the second most abundant class of bacteria, increased overall during the course of the experiment. Other bacterial classes responded in contrasting ways to the experimental incubations causing significantly different bacterial communities to develop in response to host phytoplankton species, growth phase and between attached and free-living fractions. Differences in bacterial community composition between cyanobacteria and diatom cultures were greater than between the two cyanobacteria. Despite the significance, major differences between phytoplankton cultures were in the proportion of the OTUs rather than in the absence or presence of specific taxa. Different phytoplankton species favoring different bacterial communities may have important consequences for the fate of organic matter in systems where these bloom forming species occur. The dynamics and development of transient blooms may also be affected as bacterial communities seem to influence phytoplankton species growth in contrasting ways. PMID:24465807

  14. The effects of micronutrient deficiencies on bacterial species from the human gut microbiota

    PubMed Central

    Hibberd, Matthew C.; Wu, Meng; Rodionov, Dmitry A.; Li, Xiaoqing; Cheng, Jiye; Griffin, Nicholas W.; Barratt, Michael J.; Giannone, Richard J.; Hettich, Robert L.; Osterman, Andrei L.; Gordon, Jeffrey I.

    2017-01-01

    Vitamin and mineral (micronutrient) deficiencies afflict two billion people. While the impact of these imbalances on host biology has been studied extensively, much less is known about their effects on the gut microbiota of developing or adult humans. Therefore, we established a community of cultured, sequenced human gut-derived bacterial species in gnotobiotic mice and fed the animals a defined micronutrient-sufficient diet, followed by a derivative diet devoid of vitamin A, folate, iron or zinc, followed by return to the sufficient diet. Acute vitamin A deficiency had the largest effect on bacterial community structure and meta-transcriptome, with Bacteroides vulgatus, a prominent responder, increasing its abundance in the absence of vitamin A. Applying retinol selection to a library of 30,300 B. vulgatus transposon mutants revealed that disruption of acrR abrogated retinol sensitivity. Genetic complementation studies, microbial RNA-Seq, and transcription factor binding assays disclosed that AcrR is a repressor of an adjacent AcrAB-TolC efflux system. Retinol efflux measurements in wildtype and acrR-mutant strains plus treatment with a pharmacologic inhibitor of the efflux system, revealed that AcrAB-TolC is a determinant of retinol and bile acid sensitivity in B. vulgatus. Acute vitamin A deficiency was associated with altered bile acid metabolism in vivo, raising the possibility that retinol, bile acid metabolites, and AcrAB-TolC interact to influence the fitness of B. vulgatus and perhaps other microbiota members. This type of preclinical model can help to develop mechanistic insights about and more effective treatment strategies for micronutrient deficiencies. PMID:28515336

  15. Will I Regret It? Anticipated Negative Emotions Modulate Choices in Moral Dilemmas

    PubMed Central

    Pletti, Carolina; Lotto, Lorella; Tasso, Alessandra; Sarlo, Michela

    2016-01-01

    We tested if post-decisional emotions of regret, guilt, shame, anger, and disgust can account for individuals’ choices in moral dilemmas depicting the choice of letting some people die (non-utilitarian option) or sacrificing one person to save them (utilitarian option). We collected participants’ choices and post-decisional emotional ratings for each option using Footbridge-type dilemmas, in which the sacrifice of one person is the means to save more people, and Trolley-type dilemmas, in which the sacrifice is only a side effect. Moreover, we computed the EEG Readiness Potential to test if the neural activity related to the last phase of decision-making was related to the emotional conflict. Participants reported generally stronger emotions for the utilitarian as compared to the non-utilitarian options, with the exception of anger and regret, which in Trolley-type dilemmas were stronger for the non-utilitarian option. Moreover, participants tended to choose the option that minimized the intensity of negative emotions, irrespective of dilemma type. No significant relationship between emotions and the amplitude of the Readiness Potential emerged. It is possible that anticipated post-decisional emotions play a role in earlier stages of decision-making. PMID:27999559

  16. Understanding the National Energy Dilemma.

    ERIC Educational Resources Information Center

    Georgetown Univ., Washington, DC. Center for Strategic and International Studies.

    This graphic representation of our energy dilemma provides government officials, industry, and general public with an understanding of the broad problems and complexity of our energy crisis. An energy display system projects effects of energy policies on our domestic energy situation. This display contains sheets indicating total energy flow…

  17. Prisoner's Dilemma: Reflections and Recollections.

    ERIC Educational Resources Information Center

    Rapoport, Anatol

    1995-01-01

    Traces the roots of social trap situations and describes a parasitism-symbiosis model, showing that when each organism attempts to maximize its survival potential without regard for the other's, neither does as well as when they behave collectively. Discusses a model social trap situation, "Prisoner's Dilemma" ("PD") and a…

  18. [Ethical dilemmas in health].

    PubMed

    Boléo-Tomé, J

    2009-01-01

    It is difficult to speak of ethic dilemmas in a society that has relativism as the oficial philosophical and political doctrine, i.e., stable values and behavior references, are denied, both in health care and in any other area of human knowledge. In the field of medical sciences it is even pretended to pass from the observational methodology to a field of manipulation and manipulability. It is the very Ethic that is presented as a dilemma. In these conditions one needs to know the lines of thought that are defended, to replace and make disappear the stable ethic references: ecletism, historicism, scientificism, pragmatism, and nihilism itself, that lead to the 'new ethic paradigm', that has created by itself a pseudo-spirituality. The truth is we are adrift in the 'Ethic of Convenience' which changes according to the majorities. In this setting the way to go is to rediscover the abandoned ethic values: only with an objective ethic, with sound references and foundations, it is possible to re-establish and perfect the patient-physician relationship, for a better social health. And this begins with the ethic problem of human life.

  19. Moral dilemmas and moral principles: when emotion and cognition unite.

    PubMed

    Manfrinati, Andrea; Lotto, Lorella; Sarlo, Michela; Palomba, Daniela; Rumiati, Rino

    2013-01-01

    Traditional studies on moral judgement used resolutions of moral dilemmas that were framed in terms of acceptability of the consequentialist action promoting a greater good, thus overlooking the deontological implications (choices cannot be justified by their consequences). Recently, some authors have suggested a parallelism between automatic, unreflective emotional responses and deontological moral judgements. In this study, we developed a novel experimental paradigm in which participants were required to choose between two resolutions of a moral dilemma (consequentialist and deontological). To assess whether emotions are engaged in each of the two resolutions, we asked participants to evaluate their emotional experience through the ratings of valence and arousal. Results showed that emotion is involved not only in deontological but also in consequentialist resolutions. Moreover, response times pointed out a different interplay between emotion and cognition in determining a conflict in the dilemma's resolution. In particular, when people were faced with trolley-like dilemmas we found that decisions leading to deontological resolutions were slower than decisions leading to consequentialist resolutions. We propose that this finding reflects the special (but not accepted) permission provided by the doctrine of the double effect for incidentally causing death for the sake of a good end.

  20. A Survey of Current and Projected Ethical Dilemmas of Rehabilitation Counselors

    ERIC Educational Resources Information Center

    Hartley, Michael T.; Cartwright, Brenda Y.

    2016-01-01

    Purpose: This study surveyed current and projected ethical dilemmas of rehabilitation counselors. Method: As a mixed-methods approach, the study used both quantitative and qualitative analyses. Results: Of the 211 participants who completed the survey, 116 (55.0%) reported an ethical dilemma. Based on the descriptions, common themes involved roles…

  1. A Model for Making Decisions about Ethical Dilemmas in Student Assessment

    ERIC Educational Resources Information Center

    Johnson, Robert L.; Liu, Jin; Burgess, Yin

    2017-01-01

    In this mixed-methods study we investigated the development of a generalized ethics decision-making model that can be applied in considering ethical dilemmas related to student assessment. For the study, we developed five scenarios that describe ethical dilemmas associated with student assessment. Survey participants (i.e., educators) completed an…

  2. The development and evaluation of ultrasound for the treatment of bacterial suspensions. A study of frequency, power and sonication time on cultured Bacillus species.

    PubMed

    Joyce, E; Phull, S S; Lorimer, J P; Mason, T J

    2003-10-01

    Some species of bacteria produce colonies and spores which agglomerate in spherical clusters (Bacillus subtilis) and this serves as a protection for the organisms inside against biocidal attack. Flocs of fine particles e.g. clay can entrap bacteria which can also protect them against the biocides. It is because of problems such as these that alternative methods of disinfecting water are under active investigation. One such method is the use of power ultrasound, either alone or in combination with other methods. Ultrasound is able to inactivate bacteria and deagglomerate bacterial clusters or flocs through a number of physical, mechanical and chemical effects arising from acoustic cavitation. The aim of this study was to investigate the effect of power ultrasound at different powers and frequencies on Bacillus subtilis. Viable plate count techniques were used as a measure of microbial activity. Results showed a significant increase in percent kill for Bacillus species with increasing duration of exposure and intensity of ultrasound in the low-kilohertz range (20 and 38 kHz). Results obtained at two higher frequencies (512 and 850 kHz) indicated a significant increase in bacteria count suggesting declumping. In assessing the bacterial kill with time under different sonication regimes three types of behaviour were characterized: High power ultrasound (lower frequencies) in low volumes of bacterial suspension results in a continuous reduction in bacterial cell numbers i.e. the kill rate predominates. High power ultrasound (lower frequencies) in larger volumes results in an initial rise in cell numbers suggesting declumping of the bacteria but this initial rise then falls as the declumping finishes and the kill rate becomes more important. Low intensity ultrasound (higher frequencies) gives an initial rise in cell numbers as a result of declumping. The kill rate is low and so there is no significant subsequent decrease in bacterial cell numbers.

  3. Identification of Bioethical Dilemmas, Ethical Reasoning, and Decision-Making in Military Emergency Medicine Departments

    DTIC Science & Technology

    2000-05-01

    U.S. ARMY-BAYLOR UNIVERSITY GRADUATE PROGRAM IN HEALTH CARE ADMINISTRATION IDENTIFICATION OF BIOETHICAL DILEMMAS, ETHICAL REASONING, AND DECISION...of service members and their families. ABSTRACT ii Background. Little is known about (1) the range and frequency of bioethical dilemmas that military...making in resolving these complex issues. By identifying the type and frequency of bioethical dilemmas faced by military emergency medicine

  4. The Patterns and Drivers of Bacterial and Fungal β-Diversity in a Typical Dryland Ecosystem of Northwest China.

    PubMed

    Wang, Jianming; Zhang, Tianhan; Li, Liping; Li, Jingwen; Feng, Yiming; Lu, Qi

    2017-01-01

    Dryland ecosystems cover more than 30% of the terrestrial area of China, while processes that shape the biogeographic patterns of bacterial and fungal β-diversity have rarely been evaluated synchronously. To compare the biogeographic patterns and its drivers of bacterial and fungal β-diversity, we collected 62 soil samples from a typical dryland region of northwest China. We assessed bacterial and fungal communities by sequencing bacterial 16S rRNA gene and fungal ITS data. Meanwhile, the β-diversity was decomposed into two components: species replacement (species turnover) and nestedness to further explore the bacterial and fungal β-diversity patterns and its causes. The results show that both bacterial and fungal β-diversity were derived almost entirely from species turnover rather than from species nestedness. Distance-decay relationships confirmed that the geographic patterns of bacterial and fungal β-diversity were significantly different. Environmental factors had the dominant influence on both the bacterial and fungal β-diversity and species turnover, however, the role of geographic distance varied across bacterial and fungal communities. Furthermore, both bacterial and fungal nestedness did not significantly respond to the environmental and geographic distance. Our findings suggest that the different response of bacterial and fungal species turnover to dispersal limitation and other, unknown processes may result in different biogeographic patterns of bacterial and fungal β-diversity in the drylands of northwest China. Together, we highlight that the drivers of β-diversity patterns vary between bacterial and fungal communities, and microbial β-diversity are driven by multiple factors in the drylands of northwest China.

  5. Is Drosophila-microbe association species-specific or region specific? A study undertaken involving six Indian Drosophila species.

    PubMed

    Singhal, Kopal; Khanna, Radhika; Mohanty, Sujata

    2017-06-01

    The present work aims to identify the microbial diversity associated with six Indian Drosophila species using next generation sequencing (NGS) technology and to discover the nature of their distribution across species and eco-geographic regions. Whole fly gDNA of six Drosophila species were used to generate sequences in an Illumina platform using NGS technology. De novo based assembled raw reads were blasted against the NR database of NCBI using BLASTn for identification of their bacterial loads. We have tried to include Drosophila species from different taxonomical groups and subgroups and from three different eco-climatic regions India; four species belong to Central India, while the rest two, D. melanogaster and D. ananassae, belong to West and South India to determine both their species-wise and region-wide distribution. We detected the presence of 33 bacterial genera across all six study species, predominated by the class Proteobacteria. Amongst all, D. melanogaster was found to be the most diverse by carrying around 85% of the bacterial diversity. Our findings infer both species-specific and environment-specific nature of the bacterial species inhabiting the Drosophila host. Though the present results are consistent with most of the earlier studies, they also remain incoherent with some. The present study outcome on the host-bacteria association and their species specific adaptation may provide some insight to understand the host-microbial interactions and the phenotypic implications of microbes on the host physiology. The knowledge gained may be importantly applied into the recent insect and pest population control strategy going to implement through gut microflora in India and abroad.

  6. Host plant species determines symbiotic bacterial community mediating suppression of plant defenses.

    PubMed

    Chung, Seung Ho; Scully, Erin D; Peiffer, Michelle; Geib, Scott M; Rosa, Cristina; Hoover, Kelli; Felton, Gary W

    2017-01-03

    Herbivore associated bacteria are vital mediators of plant and insect interactions. Host plants play an important role in shaping the gut bacterial community of insects. Colorado potato beetles (CPB; Leptinotarsa decemlineata) use several Solanum plants as hosts in their natural environment. We previously showed that symbiotic gut bacteria from CPB larvae suppressed jasmonate (JA)-induced defenses in tomato. However, little is known about how changes in the bacterial community may be involved in the manipulation of induced defenses in wild and cultivated Solanum plants of CPB. Here, we examined suppression of JA-mediated defense in wild and cultivated hosts of CPB by chemical elicitors and their symbiotic bacteria. Furthermore, we investigated associations between the gut bacterial community and suppression of plant defenses using 16 S rRNA amplicon sequencing. Symbiotic bacteria decreased plant defenses in all Solanum hosts and there were different gut bacterial communities in CPB fed on different host plants. When larvae were reared on different hosts, defense suppression differed among host plants. These results demonstrate that host plants influence herbivore gut bacterial communities and consequently affect the herbivore's ability to manipulate JA-mediated plant defenses. Thus, the presence of symbiotic bacteria that suppress plant defenses might help CPB adapt to host plants.

  7. Host plant species determines symbiotic bacterial community mediating suppression of plant defenses

    PubMed Central

    Chung, Seung Ho; Scully, Erin D.; Peiffer, Michelle; Geib, Scott M.; Rosa, Cristina; Hoover, Kelli; Felton, Gary W.

    2017-01-01

    Herbivore associated bacteria are vital mediators of plant and insect interactions. Host plants play an important role in shaping the gut bacterial community of insects. Colorado potato beetles (CPB; Leptinotarsa decemlineata) use several Solanum plants as hosts in their natural environment. We previously showed that symbiotic gut bacteria from CPB larvae suppressed jasmonate (JA)-induced defenses in tomato. However, little is known about how changes in the bacterial community may be involved in the manipulation of induced defenses in wild and cultivated Solanum plants of CPB. Here, we examined suppression of JA-mediated defense in wild and cultivated hosts of CPB by chemical elicitors and their symbiotic bacteria. Furthermore, we investigated associations between the gut bacterial community and suppression of plant defenses using 16 S rRNA amplicon sequencing. Symbiotic bacteria decreased plant defenses in all Solanum hosts and there were different gut bacterial communities in CPB fed on different host plants. When larvae were reared on different hosts, defense suppression differed among host plants. These results demonstrate that host plants influence herbivore gut bacterial communities and consequently affect the herbivore’s ability to manipulate JA-mediated plant defenses. Thus, the presence of symbiotic bacteria that suppress plant defenses might help CPB adapt to host plants. PMID:28045052

  8. Biodiversity of Bacterial Ecosystems in Traditional Egyptian Domiati Cheese▿

    PubMed Central

    El-Baradei, Gaber; Delacroix-Buchet, Agnès; Ogier, Jean-Claude

    2007-01-01

    Bacterial biodiversity occurring in traditional Egyptian soft Domiati cheese was studied by PCR-temporal temperature gel electrophoresis (TTGE) and PCR-denaturing gradient gel electrophoresis (DGGE). Bands were identified using a reference species database (J.-C. Ogier et al., Appl. Environ. Microbiol. 70:5628-5643, 2004); de novo bands having nonidentified migration patterns were identified by DNA sequencing. Results reveal a novel bacterial profile and extensive bacterial biodiversity in Domiati cheeses, as reflected by the numerous bands present in TTGE and DGGE patterns. The dominant lactic acid bacteria (LAB) identified were as follows: Leuconostoc mesenteroides, Lactococcus garvieae, Aerococcus viridans, Lactobacillus versmoldensis, Pediococcus inopinatus, and Lactococcus lactis. Frequent non-LAB species included numerous coagulase-negative staphylococci, Vibrio spp., Kocuria rhizophila, Kocuria kristinae, Kocuria halotolerans, Arthrobacter spp./Brachybacterium tyrofermentans. This is the first time that the majority of these species has been identified in Domiati cheese. Nearly all the dominant and frequent bacterial species are salt tolerant, and several correspond to known marine bacteria. As Domiati cheese contains 5.4 to 9.5% NaCl, we suggest that these bacteria are likely to have an important role in the ripening process. This first systematic study of the microbial composition of Domiati cheeses reveals great biodiversity and evokes a role for marine bacteria in determining cheese type. PMID:17189434

  9. Biodiversity of bacterial ecosystems in traditional Egyptian Domiati cheese.

    PubMed

    El-Baradei, Gaber; Delacroix-Buchet, Agnès; Ogier, Jean-Claude

    2007-02-01

    Bacterial biodiversity occurring in traditional Egyptian soft Domiati cheese was studied by PCR-temporal temperature gel electrophoresis (TTGE) and PCR-denaturing gradient gel electrophoresis (DGGE). Bands were identified using a reference species database (J.-C. Ogier et al., Appl. Environ. Microbiol. 70:5628-5643, 2004); de novo bands having nonidentified migration patterns were identified by DNA sequencing. Results reveal a novel bacterial profile and extensive bacterial biodiversity in Domiati cheeses, as reflected by the numerous bands present in TTGE and DGGE patterns. The dominant lactic acid bacteria (LAB) identified were as follows: Leuconostoc mesenteroides, Lactococcus garvieae, Aerococcus viridans, Lactobacillus versmoldensis, Pediococcus inopinatus, and Lactococcus lactis. Frequent non-LAB species included numerous coagulase-negative staphylococci, Vibrio spp., Kocuria rhizophila, Kocuria kristinae, Kocuria halotolerans, Arthrobacter spp./Brachybacterium tyrofermentans. This is the first time that the majority of these species has been identified in Domiati cheese. Nearly all the dominant and frequent bacterial species are salt tolerant, and several correspond to known marine bacteria. As Domiati cheese contains 5.4 to 9.5% NaCl, we suggest that these bacteria are likely to have an important role in the ripening process. This first systematic study of the microbial composition of Domiati cheeses reveals great biodiversity and evokes a role for marine bacteria in determining cheese type.

  10. Morphodynamics of growing bacterial colony

    NASA Astrophysics Data System (ADS)

    Ghosh, Pushpita; Perlekar, Prasad; Rana, Navdeep

    Self-organization into multicellular communities is a natural trend of most of the bacteria. Mutual interactions and competition among the bacterial cells in such multicellular organization play essential role in governing the spatiotemporal dynamics. We here present the spatiotemporal dynamics of growing bacterial colony using theory and a particle-based or individual-based simulation model of nonmotile cells growing utilizing a diffusing nutrient/food on a semi-solid surface by their growth and division forces and by pushing each-other through sliding motility. We show how the resource competition over a fixed amount of food, the diffusion coefficient of the nutrient and the random genetic noise govern the morphodynamics of a single species and a well-mixed two-species bacterial colonies. Our results show that for a very low initial food concentrations, colony develops fingering pattern at the front, while for intermediate values of initial food sources, the colony undergoes transitions to branched structures at the periphery and for very high values of food colony develops smoother fronts.

  11. Ethical Dilemmas for School Administrators

    ERIC Educational Resources Information Center

    Denig, Stephen J.; Quinn, Terrence

    2001-01-01

    Schools are ethical organizations. The daily schedule of educational administrators is filled with ethical dilemmas and moral decisions. As reflective practitioners, school leaders know that the decisions that are made and the values that underlie those decisions are filled with moral implications for the entire school community. In this paper,…

  12. Inter- and intra-specific cuticle variation between amphimictic and parthenogenetic species of root-knot nematode (Meloidogyne spp.) as revealed by a bacterial parasite (Pasteuria penetrans).

    PubMed

    Davies, K G; Rowe, J A; Williamson, V M

    2008-06-01

    Specific host-parasite interactions exist between species and strains of plant parasitic root-knot nematodes and the Gram-positive bacterial hyperparasite Pasteuria penetrans. This bacterium produces endospores that adhere to the cuticle of migrating juveniles, germinate and colonise the developing female within roots. Endospore attachment of P. penetrans populations to second-stage juveniles of the root-knot nematode species Meloidogyne incognita and Meloidogyne hapla showed there were interactive differences between bacterial populations and nematode species. Infected females of M. incognita produced a few progeny which were used to establish two nematode lines from single infective juveniles encumbered with either three or 26 endospores. Single juvenile descent lines of each nematode species were produced to test whether cuticle variation was greater within M. hapla lines that reproduce by facultative meiotic parthenogenesis than within lines of M. incognita, which reproduces by obligate parthenogenesis. Assays revealed variability between broods of individual females derived from single second-stage juvenile descent lines of both M. incognita and M. hapla suggesting that progeny derived from a single individual can differ in spore adhesion in both sexual and asexual nematode species. These results suggest that special mechanisms that produced these functional differences in the cuticle surface may have evolved in both sexually and asexually reproducing nematodes as a strategy to circumvent infection by this specialised hyperparasite.

  13. Plant-plant competition outcomes are modulated by plant effects on the soil bacterial community.

    PubMed

    Hortal, S; Lozano, Y M; Bastida, F; Armas, C; Moreno, J L; Garcia, C; Pugnaire, F I

    2017-12-19

    Competition is a key process that determines plant community structure and dynamics, often mediated by nutrients and water availability. However, the role of soil microorganisms on plant competition, and the links between above- and belowground processes, are not well understood. Here we show that the effects of interspecific plant competition on plant performance are mediated by feedbacks between plants and soil bacterial communities. Each plant species selects a singular community of soil microorganisms in its rhizosphere with a specific species composition, abundance and activity. When two plant species interact, the resulting soil bacterial community matches that of the most competitive plant species, suggesting strong competitive interactions between soil bacterial communities as well. We propose a novel mechanism by which changes in belowground bacterial communities promoted by the most competitive plant species influence plant performance and competition outcome. These findings emphasise the strong links between plant and soil communities, paving the way to a better understanding of plant community dynamics and the effects of soil bacterial communities on ecosystem functioning and services.

  14. Detection of bacterial pathogens including potential new species in human head lice from Mali

    PubMed Central

    Amanzougaghene, Nadia; Fenollar, Florence; Sangaré, Abdoul Karim; Sissoko, Mahamadou S.; Doumbo, Ogobara K.; Raoult, Didier

    2017-01-01

    In poor African countries, where no medical and biological facilities are available, the identification of potential emerging pathogens of concern at an early stage is challenging. Head lice, Pediculus humanus capitis, have a short life, feed only on human blood and do not transmit pathogens to their progeny. They are, therefore, a perfect tool for the xenodiagnosis of current or recent human infection. This study assessed the occurrence of bacterial pathogens from head lice collected in two rural villages from Mali, where a high frequency of head lice infestation had previously been reported, using molecular methods. Results show that all 600 head lice, collected from 117 individuals, belonged to clade E, specific to West Africa. Bartonella quintana, the causative agent of trench fever, was identified in three of the 600 (0.5%) head lice studied. Our study also shows, for the first time, the presence of the DNA of two pathogenic bacteria, namely Coxiella burnetii (5.1%) and Rickettsia aeschlimannii (0.6%), detected in human head lice, as well as the DNA of potential new species from the Anaplasma and Ehrlichia genera of unknown pathogenicity. The finding of several Malian head lice infected with B. quintana, C. burnetii, R. aeschlimannii, Anaplasma and Ehrlichia is alarming and highlights the need for active survey programs to define the public health consequences of the detection of these emerging bacterial pathogens in human head lice. PMID:28931077

  15. New insights into valve-related intramural and intracellular bacterial diversity in infective endocarditis

    PubMed Central

    Feder, Stefan; Lehmann, Stefanie; Kullnick, Yvonne; Buschmann, Tilo; Blumert, Conny; Horn, Friedemann; Neuhaus, Jochen; Neujahr, Ralph; Bagaev, Erik; Hagl, Christian; Pichlmaier, Maximilian; Rodloff, Arne Christian; Gräber, Sandra; Kirsch, Katharina; Sandri, Marcus; Kumbhari, Vivek; Behzadi, Armirhossein; Behzadi, Amirali; Correia, Joao Carlos; Mohr, Friedrich Wilhelm

    2017-01-01

    Aims In infective endocarditis (IE), a severe inflammatory disease of the endocardium with an unchanged incidence and mortality rate over the past decades, only 1% of the cases have been described as polymicrobial infections based on microbiological approaches. The aim of this study was to identify potential biodiversity of bacterial species from infected native and prosthetic valves. Furthermore, we compared the ultrastructural micro-environments to detect the localization and distribution patterns of pathogens in IE. Material and methods Using next-generation sequencing (NGS) of 16S rDNA, which allows analysis of the entire bacterial community within a single sample, we investigated the biodiversity of infectious bacterial species from resected native and prosthetic valves in a clinical cohort of 8 IE patients. Furthermore, we investigated the ultrastructural infected valve micro-environment by focused ion beam scanning electron microscopy (FIB-SEM). Results Biodiversity was detected in 7 of 8 resected heart valves. This comprised 13 bacterial genera and 16 species. In addition to 11 pathogens already described as being IE related, 5 bacterial species were identified as having a novel association. In contrast, valve and blood culture-based diagnosis revealed only 4 species from 3 bacterial genera and did not show any relevant antibiotic resistance. The antibiotics chosen on this basis for treatment, however, did not cover the bacterial spectra identified by our amplicon sequencing analysis in 4 of 8 cases. In addition to intramural distribution patterns of infective bacteria, intracellular localization with evidence of bacterial immune escape mechanisms was identified. Conclusion The high frequency of polymicrobial infections, pathogen diversity, and intracellular persistence of common IE-causing bacteria may provide clues to help explain the persistent and devastating mortality rate observed for IE. Improved bacterial diagnosis by 16S rDNA NGS that increases the

  16. Helping without harming: the instructor's feedback dilemma in debriefing--a case study.

    PubMed

    Rudolph, Jenny W; Foldy, Erica Gabrielle; Robinson, Traci; Kendall, Sandy; Taylor, Steven S; Simon, Robert

    2013-10-01

    Simulation instructors often feel caught in a task-versus-relationship dilemma. They must offer clear feedback on learners' task performance without damaging their relationship with those learners, especially in formative simulation settings. Mastering the skills to resolve this dilemma is crucial for simulation faculty development. We conducted a case study of a debriefer stuck in this task-versus-relationship dilemma. The "2-column case" captures debriefing dialogue and instructor's thoughts and feelings or the "subjective experience." The "learning pathways grid" guides a peer group of faculty in a step-by-step, retrospective analysis of the debriefing. The method uses vivid language to highlight the debriefer's dilemmas and how to surmount them. The instructor's initial approach to managing the task-versus-relationship dilemma included (1) assuming that honest critiques will damage learners, (2) using vague descriptions of learner actions paired with guess-what-I-am-thinking questions, and (3) creating a context she worried would leave learners feeling neither safe nor clear how they could improve. This case study analysis identified things the instructor could do to be more effective including (1) making generous inferences about the learners' qualities, (2) normalizing the challenges posed by the simulation, (3) assuming there are different understandings of what it means to be a team. There are key assumptions and ways of interacting that help instructors resolve the task-versus-relationship dilemma. The instructor can then provide honest feedback in a rigorous yet empathic way to help sustain good or improve suboptimal performance in the future.

  17. 76 FR 72955 - Proposed Collection; Comment Request: “Ethical Dilemmas in Surgery and Utilization of Hospital...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-28

    ... Request: ``Ethical Dilemmas in Surgery and Utilization of Hospital Ethics Consultation Service: A Survey.... Proposed Collection: Title: Ethical Dilemmas in Surgery and Utilization of Hospital Ethics Consultation...: This survey is intended to collect information about the ethical dilemmas that surgeons have faced in...

  18. Entanglement guarantees emergence of cooperation in quantum prisoner's dilemma games on networks.

    PubMed

    Li, Angsheng; Yong, Xi

    2014-09-05

    It was known that cooperation of evolutionary prisoner's dilemma games fails to emerge in homogenous networks such as random graphs. Here we proposed a quantum prisoner's dilemma game. The game consists of two players, in which each player has three choices of strategy: cooperator (C), defector (D) and super cooperator (denoted by Q). We found that quantum entanglement guarantees emergence of a new cooperation, the super cooperation of the quantum prisoner's dilemma games, and that entanglement is the mechanism of guaranteed emergence of cooperation of evolutionary prisoner's dilemma games on networks. We showed that for a game with temptation b, there exists a threshold arccos √b/b for a measurement of entanglement, beyond which, (super) cooperation of evolutionary quantum prisoner's dilemma games is guaranteed to quickly emerge, giving rise to stochastic convergence of the cooperations, that if the entanglement degree γ is less than the threshold arccos √b/b, then the equilibrium frequency of cooperations of the games is positively correlated to the entanglement degree γ, and that if γ is less than arccos √b/b and b is beyond some boundary, then the equilibrium frequency of cooperations of the games on random graphs decreases as the average degree of the graphs increases.

  19. Management dilemmas that will shape wilderness in the 21st century

    Treesearch

    David N. Cole

    2001-01-01

    How we resolve two management dilemmas will determine the future nature and value of wilderness. The first dilemma is providing for use and enjoyment while protecting wilderness conditions. The second is whether wilderness ecosystems should be left wild and “untrammeled” or, paradoxically, be manipulated toward a more natural state. Alternative solutions are explored....

  20. A quasi-universal medium to break the aerobic/anaerobic bacterial culture dichotomy in clinical microbiology.

    PubMed

    Dione, N; Khelaifia, S; La Scola, B; Lagier, J C; Raoult, D

    2016-01-01

    In the mid-19th century, the dichotomy between aerobic and anaerobic bacteria was introduced. Nevertheless, the aerobic growth of strictly anaerobic bacterial species such as Ruminococcus gnavus and Fusobacterium necrophorum, in a culture medium containing antioxidants, was recently demonstrated. We tested aerobically the culture of 623 bacterial strains from 276 bacterial species including 82 strictly anaerobic, 154 facultative anaerobic, 31 aerobic and nine microaerophilic bacterial species as well as ten fungi. The basic culture medium was based on Schaedler agar supplemented with 1 g/L ascorbic acid and 0.1 g/L glutathione (R-medium). We successively optimized this media, adding 0.4 g/L uric acid, using separate autoclaving of the component, or adding haemin 0.1 g/L or α-ketoglutarate 2 g/L. In the basic medium, 237 bacterial species and ten fungal species grew but with no growth of 36 bacterial species, including 22 strict anaerobes. Adding uric acid allowed the growth of 14 further species including eight strict anaerobes, while separate autoclaving allowed the growth of all tested bacterial strains. To extend its potential use for fastidious bacteria, we added haemin for Haemophilus influenzae, Haemophilus parainfluenzae and Eikenella corrodens and α-ketoglutarate for Legionella pneumophila. This medium allowed the growth of all tested strains with the exception of Mycobacterium tuberculosis and Mycobacterium bovis. Testing primoculture and more fastidious species will constitute the main work to be done, but R-medium coupled with a rapid identification method (matrix-assisted laser desorption/ionization time-of-flight mass spectrometry) will facilitate the anaerobic culture in clinical microbiology laboratories. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  1. Shifts in bacterial communities of two caribbean reef-building coral species affected by white plague disease

    PubMed Central

    Cárdenas, Anny; Rodriguez-R, Luis M; Pizarro, Valeria; Cadavid, Luis F; Arévalo-Ferro, Catalina

    2012-01-01

    Coral reefs are deteriorating at an alarming rate mainly as a consequence of the emergence of coral diseases. The white plague disease (WPD) is the most prevalent coral disease in the southwestern Caribbean, affecting dozens of coral species. However, the identification of a single causal agent has proved problematic. This suggests more complex etiological scenarios involving alterations in the dynamic interaction between environmental factors, the coral immune system and the symbiotic microbial communities. Here we compare the microbiome of healthy and WPD-affected corals from the two reef-building species Diploria strigosa and Siderastrea siderea collected at the Tayrona National Park in the Caribbean of Colombia. Microbiomes were analyzed by combining culture-dependent methods and pyrosequencing of 16S ribosomal DNA (rDNA) V5-V6 hypervariable regions. A total of 20 410 classifiable 16S rDNA sequences reads were obtained including all samples. No significant differences in operational taxonomic unit diversity were found between healthy and affected tissues; however, a significant increase of Alphaproteobacteria and a concomitant decrease in the Beta- and Gammaproteobacteria was observed in WPD-affected corals of both species. Significant shifts were also observed in the orders Rhizobiales, Caulobacteriales, Burkholderiales, Rhodobacterales, Aleteromonadales and Xanthomonadales, although they were not consistent between the two coral species. These shifts in the microbiome structure of WPD-affected corals suggest a loss of community-mediated growth control mechanisms on bacterial populations specific for each holobiont system. PMID:21955993

  2. Deep learning approach to bacterial colony classification.

    PubMed

    Zieliński, Bartosz; Plichta, Anna; Misztal, Krzysztof; Spurek, Przemysław; Brzychczy-Włoch, Monika; Ochońska, Dorota

    2017-01-01

    In microbiology it is diagnostically useful to recognize various genera and species of bacteria. It can be achieved using computer-aided methods, which make the recognition processes more automatic and thus significantly reduce the time necessary for the classification. Moreover, in case of diagnostic uncertainty (the misleading similarity in shape or structure of bacterial cells), such methods can minimize the risk of incorrect recognition. In this article, we apply the state of the art method for texture analysis to classify genera and species of bacteria. This method uses deep Convolutional Neural Networks to obtain image descriptors, which are then encoded and classified with Support Vector Machine or Random Forest. To evaluate this approach and to make it comparable with other approaches, we provide a new dataset of images. DIBaS dataset (Digital Image of Bacterial Species) contains 660 images with 33 different genera and species of bacteria.

  3. Dilemma between health and environmental motives when purchasing animal food products: sociodemographic and nutritional characteristics of consumers.

    PubMed

    Péneau, Sandrine; Fassier, Philippine; Allès, Benjamin; Kesse-Guyot, Emmanuelle; Hercberg, Serge; Méjean, Caroline

    2017-11-10

    Dietary guidelines in France give quantitative recommendations for intake of meat, fish and dairy products whereas consumers are increasingly concerned by the environmental impacts associated with the production of these foods. This potentially leads to consumer dilemmas when purchasing food products. The present study aimed at investigating the sociodemographic profiles of individuals reporting health and environmental dilemmas when purchasing meat, fish and dairy products, and comparing diet quality of individuals with and without dilemma. A total of 22,936 adult participants in the NutriNet-Santé cohort were included in this cross-sectional analysis. Participants completed a questionnaire assessing motives when purchasing meat, fish and dairy products, including health and environmental determinants. Environmental vs. health dilemmas were assessed using implicit and explicit methods. Sociodemographic data as well as dietary intake using repeated 24 h-records were collected. The association between sociodemographic characteristics and presence of dilemma was assessed using logistic regression models and between dilemma and intake of these products, adherence to food group guidelines, or overall dietary quality, using covariance analysis. Among participants, 13% were torn between buying meat for health reasons and to avoid buying it for environmental reasons, 12% in the case of fish and 5% in the case of dairy products. Older participants, women and low income individuals were more likely to report dilemmas. Participants reporting dilemmas for meat and dairy products consumed less of these foods (P < 0.05 and P < 0.0001, respectively) and had a better dietary quality overall (both P < 0.0001). In addition, participants with meat dilemma showed a better adherence to meat/fish/eggs guidelines (P < 0.001). Individuals reporting dilemmas concerning animal products had specific sociodemographic characteristics and showed higher diet quality overall compared

  4. Ethical Dilemmas for Academic Professionals.

    ERIC Educational Resources Information Center

    Payne, Stephen L., Ed.; Charnov, Bruce H., Ed.

    Ethical dilemmas faced by many academicians in the course of their work activities and role demands are described in eight articles and 24 case illustrations. Article titles and authors are as follows: "The Academician as Good Citizen" (Bruce H. Charnov); "Fundamental Means to Ethical Teaching" (Gordon A. Walter, Mary Ann Von Glinow); "Concern for…

  5. Fumonisin-Exposure Impairs Age-Related Ecological Succession of Bacterial Species in Weaned Pig Gut Microbiota.

    PubMed

    Mateos, Ivan; Combes, Sylvie; Pascal, Géraldine; Cauquil, Laurent; Barilly, Céline; Cossalter, Anne-Marie; Laffitte, Joëlle; Botti, Sara; Pinton, Philippe; Oswald, Isabelle P

    2018-06-05

    Pigs are highly affected by dietary mycotoxin contamination and particularly by fumonisin. The effects of fumonisin on pig intestinal health are well documented, but little is known regarding its impact on gut microbiota. We investigate the effects of the fumonisin (FB1, 12 mg/kg feed) on the fecal microbiota of piglets ( n = 6) after 0, 8, 15, 22, and 29 days of exposure. A control group of six piglets received a diet free of FB1. Bacterial community diversity, structure and taxonomic composition were carried out by V3⁻V4 16S rRNA gene sequencing. Exposure to FB1 decreases the diversity index, and shifts and constrains the structure and the composition of the bacterial community. This takes place as early as after 15 days of exposure and is at a maximum after 22 days of exposure. Compared to control, FB1 alters the ecological succession of fecal microbiota species toward higher levels of Lactobacillus and lower levels of the Lachnospiraceae and Veillonellaceae families, and particularly OTUs (Operational Taxonomic Units) of the genera Mitsuokella , Faecalibacterium and Roseburia . In conclusion, FB1 shifts and constrains age-related evolution of microbiota. The direct or indirect contribution of FB1 microbiota alteration in the global host response to FB1 toxicity remains to be investigated.

  6. Monochloramine inactivation of bacterial select agents.

    PubMed

    Rose, Laura J; Rice, Eugene W; Hodges, Lisa; Peterson, Alicia; Arduino, Matthew J

    2007-05-01

    Seven species of bacterial select agents were tested for susceptibility to monochloramine. Under test conditions, the monochloramine routinely maintained in potable water would reduce six of the species by 2 orders of magnitude within 4.2 h. Bacillus anthracis spores would require up to 3.5 days for the same inactivation with monochloramine.

  7. The effects of micronutrient deficiencies on bacterial species from the human gut microbiota.

    PubMed

    Hibberd, Matthew C; Wu, Meng; Rodionov, Dmitry A; Li, Xiaoqing; Cheng, Jiye; Griffin, Nicholas W; Barratt, Michael J; Giannone, Richard J; Hettich, Robert L; Osterman, Andrei L; Gordon, Jeffrey I

    2017-05-17

    Vitamin and mineral (micronutrient) deficiencies afflict 2 billion people. Although the impact of these imbalances on host biology has been studied extensively, much less is known about their effects on the gut microbiota of developing or adult humans. Therefore, we established a community of cultured, sequenced human gut-derived bacterial species in gnotobiotic mice and fed the animals a defined micronutrient-sufficient diet, followed by a derivative diet devoid of vitamin A, folate, iron, or zinc, followed by return to the sufficient diet. Acute vitamin A deficiency had the largest effect on bacterial community structure and metatranscriptome, with Bacteroides vulgatus, a prominent responder, increasing its abundance in the absence of vitamin A. Applying retinol selection to a library of 30,300 B. vulgatus transposon mutants revealed that disruption of acrR abrogated retinol sensitivity. Genetic complementation studies, microbial RNA sequencing, and transcription factor-binding assays disclosed that AcrR is a repressor of an adjacent AcrAB-TolC efflux system. Retinol efflux measurements in wild-type and acrR -mutant strains plus treatment with a pharmacologic inhibitor of the efflux system revealed that AcrAB-TolC is a determinant of retinol and bile acid sensitivity in B. vulgatus Acute vitamin A deficiency was associated with altered bile acid metabolism in vivo, raising the possibility that retinol, bile acid metabolites, and AcrAB-TolC interact to influence the fitness of B. vulgatus and perhaps other microbiota members. This type of preclinical model can help to develop mechanistic insights about the effects of, and more effective treatment strategies for micronutrient deficiencies. Copyright © 2017, American Association for the Advancement of Science.

  8. Proteome analysis of Arabidopsis seedlings exposed to bacterial volatiles.

    PubMed

    Kwon, Young Sang; Ryu, Choong-Min; Lee, Soohyun; Park, Hyo Bee; Han, Ki Soo; Lee, Jung Han; Lee, Kyunghee; Chung, Woo Sik; Jeong, Mi-Jeong; Kim, Hee Kyu; Bae, Dong-Won

    2010-11-01

    Plant root-associated bacteria (rhizobacteria) elicit plant basal immunity referred to as induced systemic resistance (ISR) against multiple pathogens. Among multi-bacterial determinants involving such ISR, the induction of ISR and promotion of growth by bacterial volatile compounds was previously reported. To exploit global de novo expression of plant proteins by bacterial volatiles, proteomic analysis was performed after exposure of Arabidopsis plants to the rhizobacterium Bacillus subtilis GB03. Ethylene biosynthesis enzymes were significantly up-regulated. Analysis by quantitative reverse transcriptase polymerase chain reaction confirmed that ethylene biosynthesis-related genes SAM-2, ACS4, ACS12, and ACO2 as well as ethylene response genes, ERF1, GST2, and CHIB were up-regulated by the exposure to bacterial volatiles. More interestingly, the emission of bacterial volatiles significantly up-regulated both key defense mechanisms mediated by jasmonic acid and salicylic acid signaling pathways. In addition, high accumulation of antioxidant proteins also provided evidence of decreased sensitivity to reactive oxygen species during the elicitation of ISR by bacterial volatiles. The present results suggest that the proteomic analysis of plant defense responses in bacterial volatile-mediated ISR can reveal the mechanisms of plant basal defenses orchestrated by endogenous ethylene production pathways and the generation of reactive oxygen species.

  9. Effects of Incidental Emotions on Moral Dilemma Judgments: An Analysis Using the CNI Model.

    PubMed

    Gawronski, Bertram; Conway, Paul; Armstrong, Joel; Friesdorf, Rebecca; Hütter, Mandy

    2018-02-01

    Effects of incidental emotions on moral dilemma judgments have garnered interest because they demonstrate the context-dependent nature of moral decision-making. Six experiments (N = 727) investigated the effects of incidental happiness, sadness, and anger on responses in moral dilemmas that pit the consequences of a given action for the greater good (i.e., utilitarianism) against the consistency of that action with moral norms (i.e., deontology). Using the CNI model of moral decision-making, we further tested whether the three kinds of emotions shape moral dilemma judgments by influencing (a) sensitivity to consequences, (b) sensitivity to moral norms, or (c) general preference for inaction versus action regardless of consequences and moral norms (or some combination of the three). Incidental happiness reduced sensitivity to moral norms without affecting sensitivity to consequences or general preference for inaction versus action. Incidental sadness and incidental anger did not show any significant effects on moral dilemma judgments. The findings suggest a central role of moral norms in the contribution of emotional responses to moral dilemma judgments, requiring refinements of dominant theoretical accounts and supporting the value of formal modeling approaches in providing more nuanced insights into the determinants of moral dilemma judgments. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  10. Identification of Bacterial Species in Kuwaiti Waters Through DNA Sequencing

    NASA Astrophysics Data System (ADS)

    Chen, K.

    2017-01-01

    With an objective of identifying the bacterial diversity associated with ecosystem of various Kuwaiti Seas, bacteria were cultured and isolated from 3 water samples. Due to the difficulties for cultured and isolated fecal coliforms on the selective agar plates, bacterial isolates from marine agar plates were selected for molecular identification. 16S rRNA genes were successfully amplified from the genome of the selected isolates using Universal Eubacterial 16S rRNA primers. The resulted amplification products were subjected to automated DNA sequencing. Partial 16S rDNA sequences obtained were compared directly with sequences in the NCBI database using BLAST as well as with the sequences available with Ribosomal Database Project (RDP).

  11. Gallstone Ileus: Dilemma in the Management

    PubMed Central

    Bakhshi, Girish D.; Chincholkar, Rajesh G.; Agarwal, Jasmine R.; Gupta, Madhukar R.; Gokhe, Prachiti S.; Nadkarni, Amogh R.

    2017-01-01

    Gallstone ileus is a mechanical intestinal obstruction caused due to impaction of a large gallstone within the bowel. The ideal treatment of gallstone ileus remains controversial, with the main dilemma being between a one-stage and a two-stage surgical procedure. A 69-year old male patient presented with gallstone ileus. A one-stage procedure with enterolithotomy and primary closure of duodenal fistula was done. His immediate postoperative recovery was uneventful, but after 3 weeks of surgery, he developed respiratory complications and expired of multi-organ failure. In gallstone ileus, patient presents with symptoms of intestinal obstruction. Enterolithotomy alone remains the most common operative method, but the definitive surgical management is still under research. An intraoperative dilemma between a one-stage or two-stage surgery is difficult to resolve in absence of clear guidelines. Hence, more studies are required to come to a consensus in deciding its definitive management. PMID:28808520

  12. Endosymbiont Dominated Bacterial Communities in a Dwarf Spider

    PubMed Central

    Vanthournout, Bram; Hendrickx, Frederik

    2015-01-01

    The microbial community of spiders is little known, with previous studies focussing primarily on the medical importance of spiders as vectors of pathogenic bacteria and on the screening of known cytoplasmic endosymbiont bacteria. These screening studies have been performed by means of specific primers that only amplify a selective set of endosymbionts, hampering the detection of unreported species in spiders. In order to have a more complete overview of the bacterial species that can be present in spiders, we applied a combination of a cloning assay, DGGE profiling and high-throughput sequencing on multiple individuals of the dwarf spider Oedothorax gibbosus. This revealed a co-infection of at least three known (Wolbachia, Rickettsia and Cardinium) and the detection of a previously unreported endosymbiont bacterium (Rhabdochlamydia) in spiders. 16S rRNA gene sequences of Rhabdochlamydia matched closely with those of Candidatus R. porcellionis, which is currently only reported as a pathogen from a woodlouse and with Candidatus R. crassificans reported from a cockroach. Remarkably, this bacterium appears to present in very high proportions in one of the two populations only, with all investigated females being infected. We also recovered Acinetobacter in high abundance in one individual. In total, more than 99% of approximately 4.5M high-throughput sequencing reads were restricted to these five bacterial species. In contrast to previously reported screening studies of terrestrial arthropods, our results suggest that the bacterial communities in this spider species are dominated by, or even restricted to endosymbiont bacteria. Given the high prevalence of endosymbiont species in spiders, this bacterial community pattern could be widespread in the Araneae order. PMID:25706947

  13. Reduction in bacterial load using hypochlorous acid hygiene solution on ocular skin

    PubMed Central

    Stroman, David W; Mintun, Keri; Epstein, Arthur B; Brimer, Crystal M; Patel, Chirag R; Branch, James D; Najafi-Tagol, Kathryn

    2017-01-01

    Purpose To examine the magnitude of bacterial load reduction on the surface of the periocular skin 20 minutes after application of a saline hygiene solution containing 0.01% pure hypochlorous acid (HOCl). Methods Microbiological specimens were collected immediately prior to applying the hygiene solution and again 20 minutes later. Total microbial colonies were counted and each unique colony morphology was processed to identify the bacterial species and to determine the susceptibility profile to 15 selected antibiotics. Results Specimens were analyzed from the skin samples of 71 eyes from 36 patients. Prior to treatment, 194 unique bacterial isolates belonging to 33 different species were recovered. Twenty minutes after treatment, 138 unique bacterial isolates belonging to 26 different species were identified. Staphylococci accounted for 61% of all strains recovered and Staphylococcus epidermidis strains comprised 60% of the staphylococcal strains. No substantial differences in the distribution of Gram-positive, Gram-negative, or anaerobic species were noted before and after treatment. The quantitative data demonstrated a >99% reduction in the staphylococcal load on the surface of the skin 20 minutes following application of the hygiene solution. The total S. epidermidis colony-forming units were reduced by 99.5%. The HOCl hygiene solution removed staphylococcal isolates that were resistant to multiple antibiotics equally well as those isolates that were susceptible to antibiotics. Conclusion The application of a saline hygiene solution preserved with pure HOCl acid reduced the bacterial load significantly without altering the diversity of bacterial species remaining on the skin under the lower eyelid. PMID:28458509

  14. Molecular survey of neglected bacterial pathogens reveals an abundant diversity of species and genotypes in ticks collected from animal hosts across Romania.

    PubMed

    Andersson, Martin O; Tolf, Conny; Tamba, Paula; Stefanache, Mircea; Radbea, Gabriel; Frangoulidis, Dimitrios; Tomaso, Herbert; Waldenström, Jonas; Dobler, Gerhard; Chitimia-Dobler, Lidia

    2018-03-20

    Ticks are transmitting a wide range of bacterial pathogens that cause substantial morbidity and mortality in domestic animals. The full pathogen burden transmitted by tick vectors is incompletely studied in many geographical areas, and extensive studies are required to fully understand the diversity and distribution of pathogens transmitted by ticks. We sampled 824 ticks of 11 species collected in 19 counties in Romania. Ticks were collected mainly from dogs, but also from other domestic and wild animals, and were subjected to molecular screening for pathogens. Rickettsia spp. was the most commonly detected pathogen, occurring in 10.6% (87/824) of ticks. Several species were detected: Rickettsia helvetica, R. raoultii, R. massiliae, R. monacensis, R. slovaca and R. aeschlimannii. A single occurrence of the zoonotic bacterium Bartonella vinsonii berkhoffii was detected in a tick collected from a dog. Anaplasma phagocytophilum occurred in four samples, and sequences similar to Anaplasma marginale/ovis were abundant in ticks from ruminants. In addition, molecular screening showed that ticks from dogs were carrying an Ehrlichia species identical to the HF strain as well as the enigmatic zoonotic pathogen "Candidatus Neoehrlichia mikurensis". An organism similar to E. chaffeensis or E. muris was detected in an Ixodes ricinus collected from a fox. We describe an abundant diversity of bacterial tick-borne pathogens in ticks collected from animal hosts in Romania, both on the level of species and genotypes/strains within these species. Several findings were novel for Romania, including Bartonella vinsonii subsp. berkhoffii that causes bacteremia and endocarditis in dogs. "Candidatus Neoehrlichia mikurensis" was detected in a tick collected from a dog. Previously, a single case of infection in a dog was diagnosed in Germany. The results warrant further studies on the consequences of tick-borne pathogens in domestic animals in Romania.

  15. Analytics For Distracted Driver Behavior Modeling in Dilemma Zone

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Li, Jan-Mou; Malikopoulos, Andreas; Thakur, Gautam

    2014-01-01

    In this paper, we present the results obtained and insights gained through the analysis of TRB contest data. We used exploratory analysis, regression, and clustering models for gaining insights into the driver behavior in a dilemma zone while driving under distraction. While simple exploratory analysis showed the distinguishing driver behavior patterns among different popu- lation groups in the dilemma zone, regression analysis showed statically signification relationships between groups of variables. In addition to analyzing the contest data, we have also looked into the possible impact of distracted driving on the fuel economy.

  16. Mass Customization in Schools: Strategies Dutch Secondary Schools Pursue to Cope with the Diversity-Efficiency Dilemma

    ERIC Educational Resources Information Center

    Waslander, Sietske

    2007-01-01

    Faced with the diversity-efficiency dilemma, private companies apply "mass customization" strategies to add diversity without adding costs. As schools are urged to become more "customer oriented" they also face a diversity-efficiency dilemma. This article asks how Dutch secondary schools cope with this dilemma and to what…

  17. Monochloramine Inactivation of Bacterial Select Agents▿

    PubMed Central

    Rose, Laura J.; Rice, Eugene W.; Hodges, Lisa; Peterson, Alicia; Arduino, Matthew J.

    2007-01-01

    Seven species of bacterial select agents were tested for susceptibility to monochloramine. Under test conditions, the monochloramine routinely maintained in potable water would reduce six of the species by 2 orders of magnitude within 4.2 h. Bacillus anthracis spores would require up to 3.5 days for the same inactivation with monochloramine. PMID:17400782

  18. Bacterial diversity in the oral cavity of ten healthy individuals

    PubMed Central

    Bik, Elisabeth M.; Long, Clara Davis; Armitage, Gary C.; Loomer, Peter; Emerson, Joanne; Mongodin, Emmanuel F.; Nelson, Karen E.; Gill, Steven R.; Fraser-Liggett, Claire M.; Relman, David A.

    2010-01-01

    The composition of the oral microbiota from 10 individuals with healthy oral tissues was determined using culture-independent techniques. From each individual, 26 specimens, each from different oral sites at a single point in time, were collected and pooled. An eleventh pool was constructed using portions of the subgingival specimens from all 10 individuals. The 16S rRNA gene was amplified using broad-range bacterial primers, and clone libraries from the individual and subgingival pools were constructed. From a total of 11 368 high-quality, non-chimeric, near full-length sequences, 247 species-level phylotypes (using a 99% sequence identity threshold) and 9 bacteria phyla were identified. At least 15 bacterial genera were conserved among all 10 individuals, with significant interindividual differences at the species and strain level. Comparisons of these oral bacterial sequences to near full-length sequences found previously in the large intestines and feces of other healthy individuals suggest that the mouth and intestinal tract harbor distinct sets of bacteria. Co-occurrence analysis demonstrated significant segregation of taxa when community membership was examined at the level of genus, but not at the level of species, suggesting that ecologically-significant, competitive interactions are more apparent at a broader taxonomic level than species. This study is one of the more comprehensive, high-resolution analyses of bacterial diversity within the healthy human mouth to date, and highlights the value of tools from macroecology for enhancing our understanding of bacterial ecology in human health. PMID:20336157

  19. Towards Spectral Library-free MALDI-TOF MS Bacterial Identification.

    PubMed

    Cheng, Ding; Qiao, Liang; Horvatovich, Péter

    2018-05-11

    Bacterial identification is of great importance in clinical diagnosis, environmental monitoring and food safety control. Among various strategies, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has drawn significant interests, and has been clinically used. Nevertheless, current bioinformatics solutions use spectral libraries for the identification of bacterial strains. Spectral library generation requires acquisition of MALDI-TOF spectra from monoculture bacterial colonies, which is time-consuming and not possible for many species and strains. We propose a strategy for bacterial typing by MALDI-TOF using protein sequences from public database, i.e. UniProt. Ten genes were identified to encode proteins most often observed by MALD-TOF from bacteria through 500 times repeated a 10-fold double cross-validation procedure, using 403 MALDI-TOF spectra corresponding to 14 genera, 81 species and 403 strains, and the protein sequences of 1276 species in UniProt. The 10 genes were then used to annotate peaks on MALDI-TOF spectra of bacteria for bacterial identification. With the approach, bacteria can be identified at the genus level by searching against a database containing the protein sequences of 42 genera of bacteria from UniProt. Our approach identified 84.1% of the 403 spectra correctly at the genus level. Source code of the algorithm is available at https://github.com/dipcarbon/BacteriaMSLF.

  20. Hot utilitarianism and cold deontology: Insights from a response patterns approach to sacrificial and real world dilemmas.

    PubMed

    Rosas, Alejandro; Viciana, Hugo; Caviedes, Esteban; Arciniegas, Alejandra

    2018-04-18

    Research on moral judgment with moral dilemmas suggests that "utilitarian" responses (UR) to sacrificial high-conflict dilemmas are due to decreased harm aversion, not only in individuals with clinical conditions, but also in healthy participants with high scores in antisocial personality traits. We investigated the patterns of responses to different dilemma types in healthy participants and present evidence that some URs to sacrificial dilemmas are morally motivated, as indicated by their empathic concern (EC) or primary psychopathy (PP) scores. In study 1 (N = 230) we tested students with four categories of sacrificial dilemmas featuring innocent victims. In study 2 (N = 590) we tested students with two categories of sacrificial dilemmas and two "real-world" moral dilemmas, where the agent can improve the lot of strangers by making a personal sacrifice. Results in both studies showed no decreased harm aversion in a pattern where the only UR is to the sacrificial dilemma where the number of saved people is very high, and significantly lower harm aversion only in the pattern of all-deontological respondents in Study 2. The analysis by response patterns allowed a better discrimination of the moral motivations of participants and showed that at least some of them express moral concerns in their URs.

  1. Structure of a bacterial cell surface decaheme electron conduit

    USDA-ARS?s Scientific Manuscript database

    Some bacterial species are able to utilize extracellular mineral forms of iron and manganese as respiratory electron acceptors. In Shewanella oneidensis this involves decaheme cytochromes that are located on the bacterial cell surface at the termini of trans-outer-membrane electron transfer conduits...

  2. Psychologists' Dilemmas in Career Counselling Practice

    ERIC Educational Resources Information Center

    Cardoso, Paulo Miguel; Taveira, Maria Ceu; Biscaia, Constanca Sacadura; Santos, Maria Graca

    2012-01-01

    In this study, we explored main dilemmas psychologists face in career counselling in two main professional settings: employment and education. Participants included 24 experienced Portuguese psychologists, working in employment (n = 14) and educational (n = 10) settings. We used consensual qualitative research to conduct and analyse…

  3. Putting Primary Prevention to Work: Administrative Dilemmas.

    ERIC Educational Resources Information Center

    Schwartz, Sanford

    1982-01-01

    Explores primary prevention as an integral part of community mental health practice. Considers the impact of primary prevention on the fundamental tasks of mental health administrators. Suggests ways of overcoming anticipated dilemmas. (RC)

  4. "Bringing the Message Forward": Using Poetic Re-Presentation to Solve Research Dilemmas

    ERIC Educational Resources Information Center

    Ward, Angela

    2011-01-01

    Researchers cannot always rely on traditional methods for solving research dilemmas. In a research project that explored the friendships and social relationships of four students with severe disabilities in four secondary schools in New Zealand, the author uses poetic re-presentation to solve several ethical and pragmatic research dilemmas. Within…

  5. The gut bacterial communities associated with lab-raised and field-collected ants of Camponotus fragilis (Formicidae: Formicinae).

    PubMed

    He, Hong; Wei, Cong; Wheeler, Diana E

    2014-09-01

    Camponotus is the second largest ant genus and known to harbor the primary endosymbiotic bacteria of the genus Blochmannia. However, little is known about the effect of diet and environment changes on the gut bacterial communities of these ants. We investigated the intestinal bacterial communities in the lab-raised and field-collected ants of Camponotus fragilis which is found in the southwestern United States and northern reaches of Mexico. We determined the difference of gut bacterial composition and distribution among the crop, midgut, and hindgut of the two types of colonies. Number of bacterial species varied with the methods of detection and the source of the ants. Lab-raised ants yielded 12 and 11 species using classical microbial culture methods and small-subunit rRNA genes (16S rRNAs) polymerase chain reaction-restriction fragment-length polymorphism analysis, respectively. Field-collected ants yielded just 4 and 1-3 species using the same methods. Most gut bacterial species from the lab-raised ants were unevenly distributed among the crop, midgut, and hindgut, and each section had its own dominant bacterial species. Acetobacter was the prominent bacteria group in crop, accounting for about 55 % of the crop clone library. Blochmannia was the dominant species in midgut, nearly reaching 90 % of the midgut clone library. Pseudomonas aeruginosa dominated the hindgut, accounting for over 98 % of the hindgut clone library. P. aeruginosa was the only species common to all three sections. A comparison between lab-raised and field-collected ants, and comparison with other species, shows that gut bacterial communities vary with local environment and diet. The bacterial species identified here were most likely commensals with little effect on their hosts or mild pathogens deleterious to colony health.

  6. An Examination of the Disruptive Innovation Paradox: The Application of the Innovators Dilemma to SME's

    NASA Astrophysics Data System (ADS)

    Nagle, Tadhg; Golden, William

    Managing strategic contradiction and paradoxical situations has been gaining importance in technological, innovation and management domains. As a result, more and more paradoxical instances and types have been documented in literature. The innovators dilemma is such an instance that gives a detailed description of how disruptive innovations affect firms. However, the innovators dilemma has only been applied to large organisations and more specifically industry incumbents. Through a multiple case study of six eLearning SME’s, this paper investigates the applicability of the innovators dilemma as well as the disruptive effects of Web 2.0 on the organisations. Analysing the data collected over 18 months, it was found that the innovators dilemma did indeed apply to SME’s. However, inline with the original thesis the dilemma only applied to the SME’s established (pre-2002) before the development of Web 2.0 technologies began. Furthermore, the study highlights that the post-2002 firms were also partly vulnerable to the dilemma but were able to avoid any negative effects though technological visionary leadership. In contrast, the pre-2002 firms were lacking this visionary ability and were also constrained by low risk profiles.

  7. Sidetracked by trolleys: Why sacrificial moral dilemmas tell us little (or nothing) about utilitarian judgment.

    PubMed

    Kahane, Guy

    2015-01-01

    Research into moral decision-making has been dominated by sacrificial dilemmas where, in order to save several lives, it is necessary to sacrifice the life of another person. It is widely assumed that these dilemmas draw a sharp contrast between utilitarian and deontological approaches to morality, and thereby enable us to study the psychological and neural basis of utilitarian judgment. However, it has been previously shown that some sacrificial dilemmas fail to present a genuine contrast between utilitarian and deontological options. Here, I raise deeper problems for this research paradigm. Even when sacrificial dilemmas present a contrast between utilitarian and deontological options at a philosophical level, it is misleading to interpret the responses of ordinary folk in these terms. What is currently classified as "utilitarian judgment" does not in fact share essential features of a genuine utilitarian outlook, and is better explained in terms of commonsensical moral notions. When subjects deliberate about such dilemmas, they are not deciding between opposing utilitarian and deontological solutions, but engaging in a richer process of weighing opposing moral reasons. Sacrificial dilemmas therefore tell us little about utilitarian decision-making. An alternative approach to studying proto-utilitarian tendencies in everyday moral thinking is proposed.

  8. Redox-Stratified Bacterial Communities in Sediments Associated with Multiple Lucinid Bivalve Species: Implications for Symbiosis in Changing Coastal Habitats

    NASA Astrophysics Data System (ADS)

    Paterson, A. T.; Fortier, C. M.; Long, B.; Kokesh, B. S.; Lim, S. J.; Campbell, B. J.; Anderson, L. C.; Engel, A. S.

    2017-12-01

    Lucinids, chemosymbiotic marine bivalves, occupy strong redox gradient habitats, including the rhizosphere of coastal seagrass beds and mangrove forests in subtropical to tropical ecosystems. Lucinids and their sulfide-oxidizing gammaproteobacterial endosymbionts, which are acquired from the environment, provide a critical ecosystem service by removing toxic reduced sulfur compounds from the surrounding environment, and lucinids may be an important food source to economically valuable fisheries. The habitats of Phacoides pectinatus, Stewartia floridana, Codakia orbicularis, Ctena orbiculata, and Lucina pensylvanica lucinids in Florida and San Salvador in The Bahamas were evaluated in comprehensive malacological, microbiological, and geochemical surveys. Vegetation cover included different seagrass species or calcareous green macroalgae. All sites were variably affected by anthropogenic activities, as evidenced by visible prop scars in seagrass beds, grain size distributions atypical of low energy environments (i.e., artificial fill or dredge material from nearby channels), and high levels of pyrogenic hydrocarbon compounds in sediment indicative of urbanization impact. Where present, lucinid population densities frequently exceeded 2000 individuals per cubic meter, and were typically more abundant underlying seagrass compared to unvegetated, bare sand. Dissolved oxygen and sulfide levels varied from where lucinids were recovered. The sediment bacterial communities from classified 16S rRNA gene sequences indicated that the diversity of putative anaerobic groups increased with sediment depth, but putative aerobes, including of Gammaproteobacteria related to the lucinid endosymbionts, decreased with depth. Where multiple seagrass species co-occurred, retrieved bacterial community compositions correlated to overlying seagrass species, but diversity differed from bare sand patches, including among putative free-living endosymbiont groups. As such, continued sea

  9. Bacterial Colonization and Tissue Compatibility of Denture Base Resins.

    PubMed

    Olms, Constanze; Yahiaoui-Doktor, Maryam; Remmerbach, Torsten W; Stingu, Catalina Suzana

    2018-06-15

    Currently, there is minimal clinical data regarding biofilm composition on the surface of denture bases and the clinical tissue compatibility. Therefore, the aim of this experimental study was to compare the bacterial colonization and the tissue compatibility of a hypoallergenic polyamide with a frequently used PMMA resin tested intraorally in a randomized split-mouth design. Test specimens made of polyamide ( n = 10) and PMMA ( n = 10) were attached over a molar band appliance in oral cavity of 10 subjects. A cytological smear test was done from palatal mucosa at baseline and after four weeks. The monolayers were inspected for micronuclei. After four weeks in situ, the appliance was removed. The test specimens were immediately cultivated on non-selective and selective nutrient media. All growing colonies were identified using VITEK-MS. The anonymized results were analyzed descriptively. A total of 110 different bacterial species could be isolated, including putative pathogens. An average of 17.8 different bacterial species grew on the PMMA specimens, and 17.3 on the polyamide specimens. The highest number of different bacterial species was n = 24, found on a PMMA specimen. On the two specimens, a similar bacterial distribution was observed. Micronuclei, as a marker for genotoxic potential of dental materials, were not detected. This study indicates that the composition of bacterial biofilm developed on these resins after four weeks is not influenced by the type of resin itself. The two materials showed no cytological differences. This investigation suggests that polyamide and PMMA are suitable for clinical use as denture base material.

  10. The bacterial community of entomophilic nematodes and host beetles.

    PubMed

    Koneru, Sneha L; Salinas, Heilly; Flores, Gilberto E; Hong, Ray L

    2016-05-01

    Insects form the most species-rich lineage of Eukaryotes and each is a potential host for organisms from multiple phyla, including fungi, protozoa, mites, bacteria and nematodes. In particular, beetles are known to be associated with distinct bacterial communities and entomophilic nematodes. While entomopathogenic nematodes require symbiotic bacteria to kill and reproduce inside their insect hosts, the microbial ecology that facilitates other types of nematode-insect associations is largely unknown. To illuminate detailed patterns of the tritrophic beetle-nematode-bacteria relationship, we surveyed the nematode infestation profiles of scarab beetles in the greater Los Angeles area over a five-year period and found distinct nematode infestation patterns for certain beetle hosts. Over a single season, we characterized the bacterial communities of beetles and their associated nematodes using high-throughput sequencing of the 16S rRNA gene. We found significant differences in bacterial community composition among the five prevalent beetle host species, independent of geographical origin. Anaerobes Synergistaceae and sulphate-reducing Desulfovibrionaceae were most abundant in Amblonoxia beetles, while Enterobacteriaceae and Lachnospiraceae were common in Cyclocephala beetles. Unlike entomopathogenic nematodes that carry bacterial symbionts, insect-associated nematodes do not alter the beetles' native bacterial communities, nor do their microbiomes differ according to nematode or beetle host species. The conservation of Diplogastrid nematodes associations with Melolonthinae beetles and sulphate-reducing bacteria suggests a possible link between beetle-bacterial communities and their associated nematodes. Our results establish a starting point towards understanding the dynamic interactions between soil macroinvertebrates and their microbiota in a highly accessible urban environment. © 2016 John Wiley & Sons Ltd.

  11. Species Specific Bacterial Spore Detection Using Lateral-Flow Immunoassay with DPA-Triggered Tb Luminescence

    NASA Technical Reports Server (NTRS)

    Ponce, Adrian

    2003-01-01

    A method of detecting bacterial spores incorporates (1) A method of lateral-flow immunoassay in combination with (2) A method based on the luminescence of Tb3+ ions to which molecules of dipicolinic acid (DPA) released from the spores have become bound. The present combination of lateral-flow immunoassay and DPA-triggered Tb luminescence was developed as a superior alternative to a prior lateral-flow immunoassay method in which detection involves the visual observation and/or measurement of red light scattered from colloidal gold nanoparticles. The advantage of the present combination method is that it affords both (1) High selectivity for spores of the species of bacteria that one seeks to detect (a characteristic of lateral-flow immunoassay in general) and (2) Detection sensitivity much greater (by virtue of the use of DPA-triggered Tb luminescence instead of gold nanoparticles) than that of the prior lateral-flow immunoassay method

  12. Using an Ethical Decision-Making Model to Address Ethical Dilemmas in School Counseling

    ERIC Educational Resources Information Center

    Brown, Timothy; Armstrong, Stephen A.; Bore, Samuel; Simpson, Chris

    2017-01-01

    School counselors frequently face ethical dilemmas. These dilemmas often involve relationships with principals, parents, and other stakeholders. School counselors may confront complex ethical issues involving confidentiality, student safety, parental rights,and social media. The American School Counselor Association recommends following an ethical…

  13. Subjective Theories of Indonesian Agronomy and Biology Teacher Students on Environmental Commons Dilemmas

    ERIC Educational Resources Information Center

    Koch, Sebastian; Barkmann, Jan; Sundawati, Leti; Bogeholz, Susanne

    2013-01-01

    Fostering the cognitive skills to analyse environmental "commons dilemmas" is an urgent task of environmental education globally. Commons dilemmas are characterised by structural incentives to overexploit a natural resource; their solution is particularly pressing in threatened biodiversity "hotspot" areas. Solutions to these…

  14. Bacterial communities associated with four ctenophore genera from the German Bight (North Sea).

    PubMed

    Hao, Wenjin; Gerdts, Gunnar; Peplies, Jörg; Wichels, Antje

    2015-01-01

    Intense research has been conducted on jellyfish and ctenophores in recent years. They are increasingly recognized as key elements in the marine ecosystem that serve as critical indicators and drivers of ecosystem performance and change. However, the bacterial community associated with ctenophores is still poorly investigated. Based on automated ribosomal intergenic spacer analysis (ARISA) and 16S ribosomal RNA gene amplicon pyrosequencing, we investigated bacterial communities associated with the frequently occurring ctenophore species Mnemiopsis leidyi, Beroe sp., Bolinopsis infundibulum and Pleurobrachia pileus at Helgoland Roads in the German Bight (North Sea). We observed significant differences between the associated bacterial communities of the different ctenophore species based on ARISA patterns. With respect to bacterial taxa, all ctenophore species were dominated by Proteobacteria as revealed by pyrosequencing. Mnemiopsis leidyi and P. pileus mainly harboured Gammaproteobacteria, with Marinomonas as the dominant phylotype of M. leidyi. By contrast, Pseudoalteromonas and Psychrobacter were the most abundant Gammaproteobacteria in P. pileus. Beroe sp. was mainly dominated by Alphaproteobacteria, particularly by the genus Thalassospira. For B. infundibulum, the bacterial community was composed of Alphaproteobacteria and Gammaproteobacteria in equal parts, which consisted of the genera Thalassospira and Marinomonas. In addition, the bacterial communities associated with M. leidyi display a clear variation over time that needs further investigation. Our results indicate that the bacterial communities associated with ctenophores are highly species- specific. © FEMS 2014. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  15. The protective role of endogenous bacterial communities in chironomid egg masses and larvae

    PubMed Central

    Senderovich, Yigal; Halpern, Malka

    2013-01-01

    Insects of the family Chironomidae, also known as chironomids, are distributed worldwide in a variety of water habitats. These insects display a wide range of tolerance toward metals and organic pollutions. Bacterial species known for their ability to degrade toxicants were identified from chironomid egg masses, leading to the hypothesis that bacteria may contribute to the survival of chironomids in polluted environments. To gain a better understanding of the bacterial communities that inhabit chironomids, the endogenous bacteria of egg masses and larvae were studied by 454-pyrosequencing. The microbial community of the egg masses was distinct from that of the larval stage, most likely due to the presence of one dominant bacterial Firmicutes taxon, which consisted of 28% of the total sequence reads from the larvae. This taxon may be an insect symbiont. The bacterial communities of both the egg masses and the larvae were found to include operational taxonomic units, which were closely related to species known as toxicant degraders. Furthermore, various bacterial species with the ability to detoxify metals were isolated from egg masses and larvae. Koch-like postulates were applied to demonstrate that chironomid endogenous bacterial species protect the insect from toxic heavy metals. We conclude that chironomids, which are considered pollution tolerant, are inhabited by stable endogenous bacterial communities that have a role in protecting their hosts from toxicants. This phenomenon, in which bacteria enable the continued existence of their host in hostile environments, may not be restricted only to chironomids. PMID:23804150

  16. Communal range defence in primates as a public goods dilemma

    PubMed Central

    Willems, Erik P.; Arseneau, T. Jean. M.; Schleuning, Xenia; van Schaik, Carel P.

    2015-01-01

    Classic socio-ecological theory holds that the occurrence of aggressive range defence is primarily driven by ecological incentives, most notably by the economic defendability of an area or the resources it contains. While this ecological cost–benefit framework has great explanatory power in solitary or pair-living species, comparative work on group-living primates has always found economic defendability to be a necessary, but not sufficient condition to account for the distribution of effective range defence across the taxon. This mismatch between theory and observation has recently been ascribed to a collective action problem among group members in, what is more informatively viewed as, a public goods dilemma: mounting effective defence of a communal range against intrusions by outgroup conspecifics. We here further develop this framework, and report on analyses at three levels of biological organization: across species, across populations within a single lineage and across groups and individuals within a single population. We find that communal range defence in primates very rarely involves collective action sensu stricto and that it is best interpreted as the outcome of opportunistic and strategic individual-level decisions. Whether the public good of a defended communal range is produced by solitary, joint or collective action is thus the outcome of the interplay between the unique characteristics of each individual, local and current socio-ecological conditions, and fundamental life-history traits of the species. PMID:26503678

  17. Best friends' discussions of social dilemmas.

    PubMed

    McDonald, Kristina L; Malti, Tina; Killen, Melanie; Rubin, Kenneth H

    2014-02-01

    Peer relationships, particularly friendships, have been theorized to contribute to how children and adolescents think about social and moral issues. The current study examined how young adolescent best friends (191 dyads; 53.4% female) reason together about multifaceted social dilemmas and how their reasoning is related to friendship quality. Mutually-recognized friendship dyads were videotaped discussing dilemmas entailing moral, social-conventional and prudential/pragmatic issues. Both dyad members completed a self-report measure of friendship quality. Dyadic data analyses guided by the Actor-Partner Interdependence Model indicated that adolescent and friend reports of friendship qualities were related to the forms of reasoning used during discussion. Friends who both reported that they could resolve conflicts in a constructive way were more likely to use moral reasoning than friends who reported that their conflict resolution was poor or disagreed on the quality of their conflict resolution. The findings provide evidence for the important role that friendship interaction may play in adolescents' social and moral development.

  18. Best Friends’ Discussions of Social Dilemmas

    PubMed Central

    McDonald, Kristina L.; Malti, Tina; Killen, Melanie; Rubin, Kenneth H.

    2013-01-01

    Peer relationships, particularly friendships, have been theorized to contribute to how children and adolescents think about social and moral issues. The current study examined how young adolescent best friends (191 dyads; 53.4% female) reason together about multifaceted social dilemmas and how their reasoning is related to friendship quality. Mutually-recognized friendship dyads were videotaped discussing dilemmas entailing moral, social-conventional and prudential/pragmatic issues. Both dyad members completed a self-report measure of friendship quality. Dyadic data analyses guided by the Actor-Partner Interdependence Model indicated that adolescent and friend's reports of friendship qualities were related to the forms of reasoning used during discussion. Friends who both reported that they could resolve conflicts in a constructive way were more likely to use moral reasoning than friends who reported that their conflict resolution was poor or disagreed on the quality of their conflict resolution. The findings provide evidence for the important role that friendship interaction may play in adolescents’ social and moral development. PMID:23666555

  19. Natural selection of memory-one strategies for the iterated prisoner's dilemma.

    PubMed

    Kraines, D P; Kraines, V Y

    2000-04-21

    In the iterated Prisoner's Dilemma, mutually cooperative behavior can become established through Darwinian natural selection. In simulated interactions of stochastic memory-one strategies for the Iterated Prisoner's Dilemma, Nowak and Sigmund discovered that cooperative agents using a Pavlov (Win-Stay Lose-Switch) type strategy eventually dominate a random population. This emergence follows more directly from a deterministic dynamical system based on differential reproductive success or natural selection. When restricted to an environment of memory-one agents interacting in iterated Prisoner's Dilemma games with a 1% noise level, the Pavlov agent is the only cooperative strategy and one of very few others that cannot be invaded by a similar strategy. Pavlov agents are trusting but no suckers. They will exploit weakness but repent if punished for cheating. Copyright 2000 Academic Press.

  20. Moral Dilemmas and Moral Rules

    ERIC Educational Resources Information Center

    Nichols, Shaun; Mallon, Ron

    2006-01-01

    Recent work shows an important asymmetry in lay intuitions about moral dilemmas. Most people think it is permissible to divert a train so that it will kill one innocent person instead of five, but most people think that it is not permissible to push a stranger in front of a train to save five innocents. We argue that recent emotion-based…

  1. Social Workers' Participation in the Resolution of Ethical Dilemmas in Hospice Care

    ERIC Educational Resources Information Center

    Csikai, Ellen L.

    2004-01-01

    Ethical dilemmas are inherent in every health care setting. A sample of hospice social workers with no direct access to a hospice ethics committee (N = 110) was surveyed regarding ethical issues in hospice care, how the issues were managed, and the extent to which social workers participated in resolution of ethical dilemmas. Common issues…

  2. New perspectives on bacterial ferredoxin evolution

    NASA Technical Reports Server (NTRS)

    George, D. G.; Hunt, L. T.; Yeh, L.-S. L.; Barker, W. C.

    1985-01-01

    Ferredoxins are low-molecular-weight, nonheme, iron proteins which function as electron carriers in a wide variety of electron transport chains. Howard et al. (1983) have suggested that the amino end of Azotobacter vinelandii ferredoxin shows a greater similarity to the carboxyl end of ferredoxin from Chromatium vinosum and that their half-chain sequences are homologous when the half-chains of either species are considered in inverse order. Examination of this proposition has made it necessary to reevaluate previous conclusions concerning the evolution of bacterial ferredoxin. Attention is given to the properties of the bacterial ferredoxin sequences, and the evolution of the bacterial ferredoxins.

  3. REASONS AND CONSEQUENCES OF APPLIED LEADERSHIP STYLES IN ETHICAL DILEMMAS WHEN NURSE MANAGERS MAKE DECISIONS.

    PubMed

    Zydziunaite, V; Suominen, T

    2014-09-21

    Abstract Background: Understanding the reasons and consequences of leadership styles in ethical dilemmas is fundamental to exploring nurse managers' abilities to influence outcomes for patients and nursing personnel. Purpose: To explain the associations between different leadership styles, reasons for their application and its consequences when nurse managers make decisions in ethical dilemmas. Methods: The data were collected between 15 October 2011 and 30 April 2012 by statistically validated questionnaire. The respondents (n=278) were nurse managers. The data were analyzed using SPSS 20.0, calculating Spearman's correlations, the Stepwise Regression and ANOVA. Results: The reasons for applying different leadership styles in ethical dilemmas include personal characteristics, years in work position, institutional factors, and the professional authority of nurse managers. The applied leadership styles in ethical dilemmas are associated with the consequences regarding the satisfaction of patients', relatives' and nurse managers' needs. Conclusions: Nurse managers exhibited leadership styles oriented to maintenance, focusing more on the "doing the job" than on managing the decision-making in ethical dilemmas.

  4. A new checkerboard panel for testing bacterial markers in periodontal disease.

    PubMed

    Dahlén, G; Leonhardt, A

    2006-02-01

    Various microbiological methods have been used for testing bacterial markers for periodontitis and periodontal disease progression. Most studies have used only a limited number of well recognized bacterial species. The purpose of the present study was to evaluate the association of 13 more recently identified bacterial species in a new panel in comparison with 12 previously more recognized periodontotopathogens ('old panel') using the 'checkerboard' DNA-DNA hybridization method. Fifty individuals were chosen who showed at least one site with a probing pocket depth of 6 mm or more (disease) and bleeding on probing and at least one site with a probing pocket depth of 3 mm and without bleeding on probing (health). One diseased and one healthy site on each individual were sampled with the paperpoint technique and the samples were processed in the checkerboard technique against deoxigenin-labeled whole genomic probes to 25 subgingival species representing 12 well recognized and 13 newly identified periodontitis associated species. Twenty-four (out of 25) species were detected more frequently in the subgingival plaque of diseased than healthy sites both at score 1 (> 10(4)) and score 3 (> 10(5)). A significant difference at the higher score (score 3) was noticed for all species of the old panel except for three (Streptococcus intermedius, Selenomonas noxia, and Eikenella corrodens). Of the species in the new panel only Prevotella tannerae, Filifactor alocis, and Porphyromonas endodontalis showed a statistical significant difference between diseased and healthy sites. It was concluded that P. tannerae, F. alocis, and P. endodontalis should be added to the 12 species used for routine diagnostics of periodontitis-associated bacterial flora.

  5. Dilemma zone protection on high-speed arterials.

    DOT National Transportation Integrated Search

    2014-12-01

    Driver behavior within the dilemma zone can be a major safety concern at high-speed signalized intersections, especially : for heavy trucks. The Nebraska Department of Roads (NDOR) has developed and implemented an Actuated Advance : Warning (AAW) dil...

  6. The Dilemma of Service Productivity and Service Innovation

    PubMed Central

    Aspara, Jaakko; Klein, Jan F.; Luo, Xueming; Tikkanen, Henrikki

    2017-01-01

    We conduct a systematic exploratory investigation of the effects of firms’ existing service productivity on the success of their new service innovations. Although previous research extensively addresses service productivity and service innovation, this is the first empirical study that bridges the gap between these two research streams and examines the links between the two concepts. Based on a comprehensive data set of new service introductions in a financial services market over a 14-year period, we empirically explore the relationship between a firm’s existing service productivity and the firm’s success in introducing new services to the market. The results unveil a fundamental service productivity-service innovation dilemma: Being productive in existing services increases a firm’s willingness to innovate new services proactively but decreases the firm’s capabilities of bringing these services to the market successfully. We provide specific insights into the mechanism underlying the complex relationship between a firm’s productivity in existing services, its innovation proactivity, and its service innovation success. For managers, we not only unpack and elucidate this dilemma but also demonstrate that a focused customer scope and growth market conditions may enable firms to mitigate the dilemma and successfully pursue service productivity and service innovation simultaneously. PMID:29706764

  7. Elucidating Duramycin's Bacterial Selectivity and Mode of Action on the Bacterial Cell Envelope.

    PubMed

    Hasim, Sahar; Allison, David P; Mendez, Berlin; Farmer, Abigail T; Pelletier, Dale A; Retterer, Scott T; Campagna, Shawn R; Reynolds, Todd B; Doktycz, Mitchel J

    2018-01-01

    The use of naturally occurring antimicrobial peptides provides a promising route to selectively target pathogenic agents and to shape microbiome structure. Lantibiotics, such as duramycin, are one class of bacterially produced peptidic natural products that can selectively inhibit the growth of other bacteria. However, despite longstanding characterization efforts, the microbial selectivity and mode of action of duramycin are still obscure. We describe here a suite of biological, chemical, and physical characterizations that shed new light on the selective and mechanistic aspects of duramycin activity. Bacterial screening assays have been performed using duramycin and Populus -derived bacterial isolates to determine species selectivity. Lipidomic profiles of selected resistant and sensitive strains show that the sensitivity of Gram-positive bacteria depends on the presence of phosphatidylethanolamine (PE) in the cell membrane. Further the surface and interface morphology were studied by high resolution atomic force microscopy and showed a progression of cellular changes in the cell envelope after treatment with duramycin for the susceptible bacterial strains. Together, these molecular and cellular level analyses provide insight into duramycin's mode of action and a better understanding of its selectivity.

  8. Coevolution of Vertex Weights Resolves Social Dilemma in Spatial Networks.

    PubMed

    Shen, Chen; Chu, Chen; Guo, Hao; Shi, Lei; Duan, Jiangyan

    2017-11-09

    In realistic social system, the role or influence of each individual varies and adaptively changes in time in the population. Inspired by this fact, we thus consider a new coevolution setup of game strategy and vertex weight on a square lattice. In detail, we model the structured population on a square lattice, on which the role or influence of each individual is depicted by vertex weight, and the prisoner's dilemma game has been applied to describe the social dilemma of pairwise interactions of players. Through numerical simulation, we conclude that our coevolution setup can promote the evolution of cooperation effectively. Especially, there exists a moderate value of δ for each ε that can warrant an optimal resolution of social dilemma. For a further understanding of these results, we find that intermediate value of δ enables the strongest heterogeneous distribution of vertex weight. We hope our coevolution setup of vertex weight will provide new insight for the future research.

  9. Social dilemma structure hidden behind traffic flow with route selection

    NASA Astrophysics Data System (ADS)

    Tanimoto, Jun; Nakamura, Kousuke

    2016-10-01

    Several traffic flows contain social dilemma structures. Herein, we explored a route-selection problem using a cellular automaton simulation dovetailed with evolutionary game theory. In our model, two classes of driver-agents coexist: D agents (defective strategy), which refer to traffic information for route selection to move fast, and C agents (cooperative strategy), which are insensitive to information and less inclined to move fast. Although no evidence suggests that the social dilemma structure in low density causes vehicles to move freely and that in high density causes traffic jams, we found a structure that corresponds to an n-person (multiplayer) Chicken (n-Chicken) game if the provided traffic information is inappropriate. If appropriate traffic information is given to the agents, the n-Chicken game can be solved. The information delivered to vehicles is crucial for easing the social dilemma due to urban traffic congestion when developing technologies to support the intelligent transportation system (ITS).

  10. Nurses' workplace distress and ethical dilemmas in Tanzanian health care.

    PubMed

    Häggström, Elisabeth; Mbusa, Ester; Wadensten, Barbro

    2008-07-01

    The aim of this study was to describe Tanzanian nurses' meaning of and experiences with ethical dilemmas and workplace distress in different care settings. An open question guide was used and the study focused on the answers that 29 registered nurses supplied. The theme, ;Tanzanian registered nurses' invisible and visible expressions about existential conditions in care', emerged from several subthemes as: suffering from (1) workplace distress; (2) ethical dilemmas; (3) trying to maintaining good quality nursing care; (4) lack of respect, appreciation and influence; and (5) a heavy workload that did not prevent registered nurses from struggling for better care for their patients. The analysis shows that, on a daily basis, nurses find themselves working on the edge of life and death, while they have few opportunities for doing anything about this situation. Nurses need professional guidance to gain insight and be able to reflect on their situations, so that they do not become overloaded with ethical dilemmas and workplace distress.

  11. Analysis of the Bacterial Diversity in Liver Abscess: Differences between Pyogenic and Amebic Abscesses

    PubMed Central

    Reyna-Fabián, Miriam E.; Zermeño, Valeria; Ximénez, Cecilia; Flores, Janin; Romero, Miguel F.; Diaz, Daniel; Argueta, Jesús; Moran, Patricia; Valadez, Alicia; Cerritos, René

    2016-01-01

    Several recent studies have demonstrated that virulence in Entamoeba histolytica is triggered in the presence of both pathogenic and nonpathogenic bacteria species using in vitro and in vivo experimental animal models. In this study, we examined samples aspirated from abscess material obtained from patients who were clinically diagnosed with amebic liver abscess (ALA) or pyogenic liver abscess (PLA). To determine the diversity of bacterial species in the abscesses, we performed partial 16S rRNA gene sequencing. In addition, the E. histolytica and Entamoeba dispar species were genotyped using tRNA-linked short tandem repeats as specific molecular markers. The association between clinical data and bacterial and parasite genotypes were examined through a correspondence analysis. The results showed the presence of numerous bacterial groups. These taxonomic groups constitute common members of the gut microbiota, although all of the detected bacterial species have a close phylogenetic relationship with bacterial pathogens. Furthermore, some patients clinically diagnosed with PLA and ALA were coinfected with E. dispar or E. histolytica, which suggests that the virulence of these parasites increased in the presence of bacteria. However, no specific bacterial groups were associated with this effect. Together, our results suggest a nonspecific mechanism of virulence modulation by bacteria in Entamoeba. PMID:26572872

  12. Sidetracked by trolleys: Why sacrificial moral dilemmas tell us little (or nothing) about utilitarian judgment

    PubMed Central

    Kahane, Guy

    2015-01-01

    Research into moral decision-making has been dominated by sacrificial dilemmas where, in order to save several lives, it is necessary to sacrifice the life of another person. It is widely assumed that these dilemmas draw a sharp contrast between utilitarian and deontological approaches to morality, and thereby enable us to study the psychological and neural basis of utilitarian judgment. However, it has been previously shown that some sacrificial dilemmas fail to present a genuine contrast between utilitarian and deontological options. Here, I raise deeper problems for this research paradigm. Even when sacrificial dilemmas present a contrast between utilitarian and deontological options at a philosophical level, it is misleading to interpret the responses of ordinary folk in these terms. What is currently classified as “utilitarian judgment” does not in fact share essential features of a genuine utilitarian outlook, and is better explained in terms of commonsensical moral notions. When subjects deliberate about such dilemmas, they are not deciding between opposing utilitarian and deontological solutions, but engaging in a richer process of weighing opposing moral reasons. Sacrificial dilemmas therefore tell us little about utilitarian decision-making. An alternative approach to studying proto-utilitarian tendencies in everyday moral thinking is proposed. PMID:25791902

  13. Community-acquired bacterial meningitis.

    PubMed

    van de Beek, Diederik; Brouwer, Matthijs; Hasbun, Rodrigo; Koedel, Uwe; Whitney, Cynthia G; Wijdicks, Eelco

    2016-11-03

    Meningitis is an inflammation of the meninges and subarachnoid space that can also involve the brain cortex and parenchyma. It can be acquired spontaneously in the community - community-acquired bacterial meningitis - or in the hospital as a complication of invasive procedures or head trauma (nosocomial bacterial meningitis). Despite advances in treatment and vaccinations, community-acquired bacterial meningitis remains one of the most important infectious diseases worldwide. Streptococcus pneumoniae and Neisseria meningitidis are the most common causative bacteria and are associated with high mortality and morbidity; vaccines targeting these organisms, which have designs similar to the successful vaccine that targets Haemophilus influenzae type b meningitis, are now being used in many routine vaccination programmes. Experimental and genetic association studies have increased our knowledge about the pathogenesis of bacterial meningitis. Early antibiotic treatment improves the outcome, but the growing emergence of drug resistance as well as shifts in the distribution of serotypes and groups are fuelling further development of new vaccines and treatment strategies. Corticosteroids were found to be beneficial in high-income countries depending on the bacterial species. Further improvements in the outcome are likely to come from dampening the host inflammatory response and implementing preventive measures, especially the development of new vaccines.

  14. An Overview of the Evolution of Infrared Spectroscopy Applied to Bacterial Typing.

    PubMed

    Quintelas, Cristina; Ferreira, Eugénio C; Lopes, João A; Sousa, Clara

    2018-01-01

    The sustained emergence of new declared bacterial species makes typing a continuous challenge for microbiologists. Molecular biology techniques have a very significant role in the context of bacterial typing, but they are often very laborious, time consuming, and eventually fail when dealing with very closely related species. Spectroscopic-based techniques appear in some situations as a viable alternative to molecular methods with advantages in terms of analysis time and cost. Infrared and mass spectrometry are among the most exploited techniques in this context: particularly, infrared spectroscopy emerged as a very promising method with multiple reported successful applications. This article presents a systematic review on infrared spectroscopy applications for bacterial typing, highlighting fundamental aspects of infrared spectroscopy, a detailed literature review (covering different taxonomic levels and bacterial species), advantages, and limitations of the technique over molecular biology methods and a comparison with other competing spectroscopic techniques such as MALDI-TOF MS, Raman, and intrinsic fluorescence. Infrared spectroscopy possesses a high potential for bacterial typing at distinct taxonomic levels and worthy of further developments and systematization. The development of databases appears fundamental toward the establishment of infrared spectroscopy as a viable method for bacterial typing. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Influence of bacterial interactions on pneumococcal colonization of the nasopharynx

    PubMed Central

    Shak, Joshua R.; Vidal, Jorge E.; Klugman, Keith P.

    2013-01-01

    Streptococcus pneumoniae (the pneumococcus) is a common commensal inhabitant of the nasopharynx and a frequent etiologic agent in serious diseases such as pneumonia, otitis media, bacteremia, and meningitis. Multiple pneumococcal strains can colonize the nasopharynx, which is also home to many other bacterial species. Intraspecies and interspecies interactions influence pneumococcal carriage in important ways. Co-colonization by two or more pneumococcal strains has implications for vaccine serotype replacement, carriage detection, and pneumonia diagnostics. Interactions between the pneumococcus and other bacterial species alter carriage prevalence, modulate virulence, and affect biofilm formation. By examining these interactions, this review highlights how the bacterial ecosystem of the nasopharynx changes the nature and course of pneumococcal carriage. PMID:23273566

  16. The quest for bacterial allergens.

    PubMed

    Nordengrün, Maria; Michalik, Stephan; Völker, Uwe; Bröker, Barbara M; Gómez-Gascón, Lidia

    2018-04-26

    Allergies are complex diseases featuring local tissue inflammation, which is characterized by an exaggerated type 2 immune response to environmental compounds known as allergens. Pollens, environmental fungi, and house dust mites are examples of common allergens. Bacteria have a dual role in allergy. Usually, they are associated with protection, however, certain bacterial species promote the development and exacerbation of allergic inflammation. Notably, IgE antibodies specific for bacterial antigens are found in the sera of allergic individuals. This implies that some bacterial factors are allergens, eliciting a specific type 2 immune response. However, to date, only a few of these are molecularly defined. This review summarizes the current knowledge about known bacterial allergens, and it provides an overview of the available techniques for the discovery of new allergens as well as for measuring the immune responses directed against them. Copyright © 2018 The Authors. Published by Elsevier GmbH.. All rights reserved.

  17. The analysis and resolution of ethical dilemmas.

    PubMed

    Macauley, Robert C

    2013-01-01

    Perhaps no other field of medicine illustrates the ethical dilemmas occasioned by the explosion of technology more than neurology. Many dilemmas which at first appear to be ethical, however, are actually biotechnical, informational, or interpersonal in nature. For those which are, indeed, ethical, a review of existing information and acquisition of additional data can often serve to identify the proper response. When the optimal course of action remains unclear, the comprehensive, structured approach described in this chapter is both philosophically rigorous and clinically relevant. It takes into account a variety of critical considerations - including rights, duties, consequences, virtues, and similar cases - while utilizing both inductive and deductive methods. The end result is the "least bad" of available options, or, at the very least, a practical response which preserves future options and avoids crucial mistakes. © 2013 Elsevier B.V. All rights reserved.

  18. Do honeybees shape the bacterial community composition in floral nectar?

    PubMed

    Aizenberg-Gershtein, Yana; Izhaki, Ido; Halpern, Malka

    2013-01-01

    Floral nectar is considered the most important reward animal-pollinated plants offer to attract pollinators. Here we explore whether honeybees, which act as pollinators, affect the composition of bacterial communities in the nectar. Nectar and honeybees were sampled from two plant species: Amygdalus communis and Citrus paradisi. To prevent the contact of nectar with pollinators, C. paradisi flowers were covered with net bags before blooming (covered flowers). Comparative analysis of bacterial communities in the nectar and on the honeybees was performed by the 454-pyrosequencing technique. No significant differences were found among bacterial communities in honeybees captured on the two different plant species. This resemblance may be due to the presence of dominant bacterial OTUs, closely related to the Arsenophonus genus. The bacterial communities of the nectar from the covered and uncovered C. paradisi flowers differed significantly; the bacterial communities on the honeybees differed significantly from those in the covered flowers' nectar, but not from those in the uncovered flowers' nectar. We conclude that the honeybees may introduce bacteria into the nectar and/or may be contaminated by bacteria introduced into the nectar by other sources such as other pollinators and nectar thieves.

  19. Do Honeybees Shape the Bacterial Community Composition in Floral Nectar?

    PubMed Central

    Aizenberg-Gershtein, Yana; Izhaki, Ido; Halpern, Malka

    2013-01-01

    Floral nectar is considered the most important reward animal-pollinated plants offer to attract pollinators. Here we explore whether honeybees, which act as pollinators, affect the composition of bacterial communities in the nectar. Nectar and honeybees were sampled from two plant species: Amygdalus communis and Citrus paradisi. To prevent the contact of nectar with pollinators, C. paradisi flowers were covered with net bags before blooming (covered flowers). Comparative analysis of bacterial communities in the nectar and on the honeybees was performed by the 454-pyrosequencing technique. No significant differences were found among bacterial communities in honeybees captured on the two different plant species. This resemblance may be due to the presence of dominant bacterial OTUs, closely related to the Arsenophonus genus. The bacterial communities of the nectar from the covered and uncovered C. paradisi flowers differed significantly; the bacterial communities on the honeybees differed significantly from those in the covered flowers’ nectar, but not from those in the uncovered flowers’ nectar. We conclude that the honeybees may introduce bacteria into the nectar and/or may be contaminated by bacteria introduced into the nectar by other sources such as other pollinators and nectar thieves. PMID:23844027

  20. Bacteriophage-Based Bacterial Wilt Biocontrol for an Environmentally Sustainable Agriculture

    PubMed Central

    Álvarez, Belén; Biosca, Elena G.

    2017-01-01

    Bacterial wilt diseases caused by Ralstonia solanacearum, R. pseudosolanacearum, and R. syzygii subsp. indonesiensis (former R. solanacearum species complex) are among the most important plant diseases worldwide, severely affecting a high number of crops and ornamentals. Difficulties of bacterial wilt control by non-biological methods are related to effectiveness, bacterial resistance and environmental impact. Alternatively, a great many biocontrol strategies have been carried out, with the advantage of being environmentally friendly. Advances in bacterial wilt biocontrol include an increasing interest in bacteriophage-based treatments as a promising re-emerging strategy. Bacteriophages against the bacterial wilt pathogens have been described with either lytic or lysogenic effect but, they were proved to be active against strains belonging to R. pseudosolanacearum and/or R. syzygii subsp. indonesiensis, not to the present R. solanacearum species, and only two of them demonstrated successful biocontrol potential in planta. Despite the publication of three patents on the topic, until now no bacteriophage-based product is commercially available. Therefore, there is still much to be done to incorporate valid bacteriophages in an integrated management program to effectively fight bacterial wilt in the field. PMID:28769942

  1. Bacteriophage-Based Bacterial Wilt Biocontrol for an Environmentally Sustainable Agriculture.

    PubMed

    Álvarez, Belén; Biosca, Elena G

    2017-01-01

    Bacterial wilt diseases caused by Ralstonia solanacearum , R. pseudosolanacearum , and R. syzygii subsp. indonesiensis (former R. solanacearum species complex) are among the most important plant diseases worldwide, severely affecting a high number of crops and ornamentals. Difficulties of bacterial wilt control by non-biological methods are related to effectiveness, bacterial resistance and environmental impact. Alternatively, a great many biocontrol strategies have been carried out, with the advantage of being environmentally friendly. Advances in bacterial wilt biocontrol include an increasing interest in bacteriophage-based treatments as a promising re-emerging strategy. Bacteriophages against the bacterial wilt pathogens have been described with either lytic or lysogenic effect but, they were proved to be active against strains belonging to R. pseudosolanacearum and/or R. syzygii subsp. indonesiensis , not to the present R. solanacearum species, and only two of them demonstrated successful biocontrol potential in planta . Despite the publication of three patents on the topic, until now no bacteriophage-based product is commercially available. Therefore, there is still much to be done to incorporate valid bacteriophages in an integrated management program to effectively fight bacterial wilt in the field.

  2. The Marihuana Dilemma: Challenge to Commanders.

    DTIC Science & Technology

    The marihuana dilemma poses a major challenge to commanders in the US Army today. The problem was analyzed as to the characteristics of the drug...available to commanders to meet the challenge. The essay concludes that marihuana should not be legalized; drug users or former drug users should not be

  3. Identification of Uncultured Bacterial Species from Firmicutes, Bacteroidetes and CANDIDATUS Saccharibacteria as Candidate Cellulose Utilizers from the Rumen of Beef Cows

    PubMed Central

    Opdahl, Lee James; Gonda, Michael G.

    2018-01-01

    The ability of ruminants to utilize cellulosic biomass is a result of the metabolic activities of symbiotic microbial communities that reside in the rumen. To gain further insight into this complex microbial ecosystem, a selection-based batch culturing approach was used to identify candidate cellulose-utilizing bacterial consortia. Prior to culturing with cellulose, rumen contents sampled from three beef cows maintained on a forage diet shared 252 Operational Taxonomic Units (OTUs), accounting for 41.6–50.0% of bacterial 16S rRNA gene sequences in their respective samples. Despite this high level of overlap, only one OTU was enriched in cellulose-supplemented cultures from all rumen samples. Otherwise, each set of replicate cellulose supplemented cultures originating from a sampled rumen environment was found to have a distinct bacterial composition. Two of the seven most enriched OTUs were closely matched to well-established rumen cellulose utilizers (Ruminococcus flavefaciens and Fibrobacter succinogenes), while the others did not show high nucleotide sequence identity to currently defined bacterial species. The latter were affiliated to Prevotella (1 OTU), Ruminococcaceae (3 OTUs), and the candidate phylum Saccharibacteria (1 OTU), respectively. While further investigations will be necessary to elucidate the metabolic function(s) of each enriched OTU, these results together further support cellulose utilization as a ruminal metabolic trait shared across vast phylogenetic distances, and that the rumen is an environment conducive to the selection of a broad range of microbial adaptations for the digestion of plant structural polysaccharides. PMID:29495256

  4. Identification of Uncultured Bacterial Species from Firmicutes, Bacteroidetes and CANDIDATUS Saccharibacteria as Candidate Cellulose Utilizers from the Rumen of Beef Cows.

    PubMed

    Opdahl, Lee James; Gonda, Michael G; St-Pierre, Benoit

    2018-02-24

    The ability of ruminants to utilize cellulosic biomass is a result of the metabolic activities of symbiotic microbial communities that reside in the rumen. To gain further insight into this complex microbial ecosystem, a selection-based batch culturing approach was used to identify candidate cellulose-utilizing bacterial consortia. Prior to culturing with cellulose, rumen contents sampled from three beef cows maintained on a forage diet shared 252 Operational Taxonomic Units (OTUs), accounting for 41.6-50.0% of bacterial 16S rRNA gene sequences in their respective samples. Despite this high level of overlap, only one OTU was enriched in cellulose-supplemented cultures from all rumen samples. Otherwise, each set of replicate cellulose supplemented cultures originating from a sampled rumen environment was found to have a distinct bacterial composition. Two of the seven most enriched OTUs were closely matched to well-established rumen cellulose utilizers ( Ruminococcus flavefaciens and Fibrobacter succinogenes ), while the others did not show high nucleotide sequence identity to currently defined bacterial species. The latter were affiliated to Prevotella (1 OTU), Ruminococcaceae (3 OTUs), and the candidate phylum Saccharibacteria (1 OTU), respectively. While further investigations will be necessary to elucidate the metabolic function(s) of each enriched OTU, these results together further support cellulose utilization as a ruminal metabolic trait shared across vast phylogenetic distances, and that the rumen is an environment conducive to the selection of a broad range of microbial adaptations for the digestion of plant structural polysaccharides.

  5. "Carbon gain vs. water saving, growth vs. defence": two dilemmas with soluble phenolics as a joker.

    PubMed

    Karabourniotis, George; Liakopoulos, Georgios; Nikolopoulos, Dimosthenis; Bresta, Panagiota; Stavroulaki, Vassiliki; Sumbele, Sally

    2014-10-01

    Despite that phenolics are considered as a major weapon against herbivores and pathogens, the primal reason for their evolution may have been the imperative necessity for their UV-absorbing and antioxidant properties in order for plants to compensate for the adverse terrestrial conditions. In dry climates the choice concerning the first dilemma (carbon gain vs. water saving) needs the appropriate structural and metabolic modulations, which protect against stresses such as high UV and visible radiation or drought, but reduce photosynthesis and increase oxidative pressure. Thus, when water saving is chosen, priority is given to protection (including phenolic synthesis), instead of carbon gain and hence growth. At the global level, the different choices by the individual species are expressed by an interspecific negative relationship between total phenolics and photosynthesis. On the other hand, the accumulation of phenolics in water saving plants offers additional defensive functions because these multifunctional compounds can also act as pro-oxidant, antifeeding or toxic factors. Therefore phenolics, as biochemical jokers, can give the answer to both dilemmas: water saving involves high concentrations of phenolics which also offer high level of defence. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  6. Dissolving the engineering moral dilemmas within the Islamic ethico-legal praxes.

    PubMed

    Solihu, Abdul Kabir Hussain; Ambali, Abdul Rauf

    2011-03-01

    The goal of responsible engineers is the creation of useful and safe technological products and commitment to public health, while respecting the autonomy of the clients and the public. Because engineers often face moral dilemma to resolve such issues, different engineers have chosen different course of actions depending on their respective moral value orientations. Islam provides a value-based mechanism rooted in the Maqasid al-Shari'ah (the objectives of Islamic law). This mechanism prioritizes some values over others and could help resolve the moral dilemmas faced in engineering. This paper introduces the Islamic interpretive-evaluative maxims to two core issues in engineering ethics: genetically modified foods and whistleblowing. The study aims primarily to provide problem-solving maxims within the Maqasid al-Shari'ah matrix through which such moral dilemmas in science and engineering could be studied and resolved.

  7. Evolutionary dynamics of the traveler's dilemma and minimum-effort coordination games on complex networks.

    PubMed

    Iyer, Swami; Killingback, Timothy

    2014-10-01

    The traveler's dilemma game and the minimum-effort coordination game are social dilemmas that have received significant attention resulting from the fact that the predictions of classical game theory are inconsistent with the results found when the games are studied experimentally. Moreover, both the traveler's dilemma and the minimum-effort coordination games have potentially important applications in evolutionary biology. Interestingly, standard deterministic evolutionary game theory, as represented by the replicator dynamics in a well-mixed population, is also inadequate to account for the behavior observed in these games. Here we study the evolutionary dynamics of both these games in populations with interaction patterns described by a variety of complex network topologies. We investigate the evolutionary dynamics of these games through agent-based simulations on both model and empirical networks. In particular, we study the effects of network clustering and assortativity on the evolutionary dynamics of both games. In general, we show that the evolutionary behavior of the traveler's dilemma and minimum-effort coordination games on complex networks is in good agreement with that observed experimentally. Thus, formulating the traveler's dilemma and the minimum-effort coordination games on complex networks neatly resolves the paradoxical aspects of these games.

  8. Evolutionary dynamics of the traveler's dilemma and minimum-effort coordination games on complex networks

    NASA Astrophysics Data System (ADS)

    Iyer, Swami; Killingback, Timothy

    2014-10-01

    The traveler's dilemma game and the minimum-effort coordination game are social dilemmas that have received significant attention resulting from the fact that the predictions of classical game theory are inconsistent with the results found when the games are studied experimentally. Moreover, both the traveler's dilemma and the minimum-effort coordination games have potentially important applications in evolutionary biology. Interestingly, standard deterministic evolutionary game theory, as represented by the replicator dynamics in a well-mixed population, is also inadequate to account for the behavior observed in these games. Here we study the evolutionary dynamics of both these games in populations with interaction patterns described by a variety of complex network topologies. We investigate the evolutionary dynamics of these games through agent-based simulations on both model and empirical networks. In particular, we study the effects of network clustering and assortativity on the evolutionary dynamics of both games. In general, we show that the evolutionary behavior of the traveler's dilemma and minimum-effort coordination games on complex networks is in good agreement with that observed experimentally. Thus, formulating the traveler's dilemma and the minimum-effort coordination games on complex networks neatly resolves the paradoxical aspects of these games.

  9. How Culture Matters in Educational Borrowing? Chinese Teachers' Dilemmas in a Global Era

    ERIC Educational Resources Information Center

    Liu, Sheng-nan; Feng, Da-ming

    2015-01-01

    Educational borrowing may cause numerous dilemmas that emerge from cross-cultural differences among teachers in the globalization. Through the case study on the flipped classroom introduced from the United States into Chinese middle schools, this article presents an examination of dilemmas that teachers encountered during educational borrowing in…

  10. Shapley value redistribution of social wealth fosters cooperation in social dilemmas

    NASA Astrophysics Data System (ADS)

    Krawczyk, Przemysław; Płatkowski, Tadeusz

    2018-02-01

    We consider multiplayer social dilemma games played in a large population. The members of the population interact in randomly formed coalitions. Each coalition generates a social wealth (value), which is distributed among the coalition members according to their Shapley values. Evolution of the whole population is governed by the replicator equation. We demonstrate that application of the Shapley value fosters the time asymptotic cooperation in populations for various types of multiplayer social dilemmas.

  11. Complex traffic flow that allows as well as hampers lane-changing intrinsically contains social-dilemma structures

    NASA Astrophysics Data System (ADS)

    Iwamura, Yoshiro; Tanimoto, Jun

    2018-02-01

    To investigate an interesting question as to whether or not social dilemma structures can be found in a realistic traffic flow reproduced by a model, we built a new microscopic model in which an intentional driver may try lane-changing to go in front of other vehicles and may hamper others’ lane-changes. Our model consists of twofold parts; cellular automaton emulating a real traffic flow and evolutionary game theory to implement a driver’s decision making-process. Numerical results reveal that a social dilemma like the multi-player chicken game or prisoner’s dilemma game emerges depending on the traffic phase. This finding implies that a social dilemma, which has been investigated by applied mathematics so far, hides behind a traffic flow, which has been explored by fluid dynamics. Highlight - Complex system of traffic flow with consideration of driver’s decision making process is concerned. - A new model dovetailing cellular automaton with game theory is established. - Statistical result from numerical simulations reveals a social dilemma structure underlying traffic flow. - The social dilemma is triggered by a driver’s egocentric actions of lane-changing and hampering other’s lane-change.

  12. Comparative Genomics of Facultative Bacterial Symbionts Isolated from European Orius Species Reveals an Ancestral Symbiotic Association

    PubMed Central

    Chen, Xiaorui; Hitchings, Matthew D.; Mendoza, José E.; Balanza, Virginia; Facey, Paul D.; Dyson, Paul J.; Bielza, Pablo; Del Sol, Ricardo

    2017-01-01

    Pest control in agriculture employs diverse strategies, among which the use of predatory insects has steadily increased. The use of several species within the genus Orius in pest control is widely spread, particularly in Mediterranean Europe. Commercial mass rearing of predatory insects is costly, and research efforts have concentrated on diet manipulation and selective breeding to reduce costs and improve efficacy. The characterisation and contribution of microbial symbionts to Orius sp. fitness, behaviour, and potential impact on human health has been neglected. This paper provides the first genome sequence level description of the predominant culturable facultative bacterial symbionts associated with five Orius species (O. laevigatus, O. niger, O. pallidicornis, O. majusculus, and O. albidipennis) from several geographical locations. Two types of symbionts were broadly classified as members of the genera Serratia and Leucobacter, while a third constitutes a new genus within the Erwiniaceae. These symbionts were found to colonise all the insect specimens tested, which evidenced an ancestral symbiotic association between these bacteria and the genus Orius. Pangenome analyses of the Serratia sp. isolates offered clues linking Type VI secretion system effector–immunity proteins from the Tai4 sub-family to the symbiotic lifestyle. PMID:29067021

  13. Isolation and characterization of a novel violacein-like pigment producing psychrotrophic bacterial species Janthinobacterium svalbardensis sp. nov.

    PubMed

    Ambrožič Avguštin, Jerneja; Žgur Bertok, Darja; Kostanjšek, Rok; Avguštin, Gorazd

    2013-04-01

    A bacterial strain designated JA-1, related to Janthinobacterium lividum, was isolated from glacier ice samples from the island Spitsbergen in the Arctic. The strain was tested for phenotypic traits and the most prominent appeared to be the dark red brown to black pigmentation different from the violet pigment of Janthinobacterium, Chromobacterium and Iodobacter. Phylogenetic analysis based on 16S rRNA gene sequences and DNA-DNA hybridization tests showed that strain JA-1 belongs to the genus Janthinobacterium but represents a novel lineage distinct from the two known species of this genus, J. lividum and Janthinobacterium agaricidamnosum. The DNA G + C content of strain JA-1 was determined to be 62.3 mol %. The isolate is a psychrotrophic Gram negative bacterium, rod-shaped with rounded ends, containing intracellular inclusions and one polar flagellum. On the basis of the presented results strain JA-1 is proposed as the type strain of a novel species of the genus Janthinobacterium, for which the name Janthinobacterium svalbardensis sp. nov. is proposed (JA-1(T) = DSM 25734, ZIM B637).

  14. Bacterial Quorum Sensing and Microbial Community Interactions

    PubMed Central

    2018-01-01

    ABSTRACT Many bacteria use a cell-cell communication system called quorum sensing to coordinate population density-dependent changes in behavior. Quorum sensing involves production of and response to diffusible or secreted signals, which can vary substantially across different types of bacteria. In many species, quorum sensing modulates virulence functions and is important for pathogenesis. Over the past half-century, there has been a significant accumulation of knowledge of the molecular mechanisms, signal structures, gene regulons, and behavioral responses associated with quorum-sensing systems in diverse bacteria. More recent studies have focused on understanding quorum sensing in the context of bacterial sociality. Studies of the role of quorum sensing in cooperative and competitive microbial interactions have revealed how quorum sensing coordinates interactions both within a species and between species. Such studies of quorum sensing as a social behavior have relied on the development of “synthetic ecological” models that use nonclonal bacterial populations. In this review, we discuss some of these models and recent advances in understanding how microbes might interact with one another using quorum sensing. The knowledge gained from these lines of investigation has the potential to guide studies of microbial sociality in natural settings and the design of new medicines and therapies to treat bacterial infections. PMID:29789364

  15. Bacterial α2-macroglobulins: colonization factors acquired by horizontal gene transfer from the metazoan genome?

    PubMed Central

    Budd, Aidan; Blandin, Stephanie; Levashina, Elena A; Gibson, Toby J

    2004-01-01

    Background Invasive bacteria are known to have captured and adapted eukaryotic host genes. They also readily acquire colonizing genes from other bacteria by horizontal gene transfer. Closely related species such as Helicobacter pylori and Helicobacter hepaticus, which exploit different host tissues, share almost none of their colonization genes. The protease inhibitor α2-macroglobulin provides a major metazoan defense against invasive bacteria, trapping attacking proteases required by parasites for successful invasion. Results Database searches with metazoan α2-macroglobulin sequences revealed homologous sequences in bacterial proteomes. The bacterial α2-macroglobulin phylogenetic distribution is patchy and violates the vertical descent model. Bacterial α2-macroglobulin genes are found in diverse clades, including purple bacteria (proteobacteria), fusobacteria, spirochetes, bacteroidetes, deinococcids, cyanobacteria, planctomycetes and thermotogae. Most bacterial species with bacterial α2-macroglobulin genes exploit higher eukaryotes (multicellular plants and animals) as hosts. Both pathogenically invasive and saprophytically colonizing species possess bacterial α2-macroglobulins, indicating that bacterial α2-macroglobulin is a colonization rather than a virulence factor. Conclusions Metazoan α2-macroglobulins inhibit proteases of pathogens. The bacterial homologs may function in reverse to block host antimicrobial defenses. α2-macroglobulin was probably acquired one or more times from metazoan hosts and has then spread widely through other colonizing bacterial species by more than 10 independent horizontal gene transfers. yfhM-like bacterial α2-macroglobulin genes are often found tightly linked with pbpC, encoding an atypical peptidoglycan transglycosylase, PBP1C, that does not function in vegetative peptidoglycan synthesis. We suggest that YfhM and PBP1C are coupled together as a periplasmic defense and repair system. Bacterial α2-macroglobulins might

  16. Comparison of Ethical Dilemmas across Public and Private Sectors in Rehabilitation Counseling Practice

    ERIC Educational Resources Information Center

    Beveridge, Scott; Garcia, Jorge; Siblo, Matt

    2015-01-01

    Purpose: To examine the nature of ethical dilemmas most frequently reported by rehabilitation counselors in the private and public sectors and determine if significant differences exist in how practitioners experience ethical dilemmas in these two settings. Method: A mixed-methods internet-based survey design was utilized and included descriptive,…

  17. Virtue ethics: an approach to moral dilemmas in nursing.

    PubMed

    Arries, E

    2005-08-01

    Nurses are increasingly confronted with situations of moral difficulty, such as not to feed terminally ill patients, whistle blowing, or participation in termination of pregnancy. Most of these moral dilemmas are often analyzed using the principle-based approach which applies the four moral principles of justice, autonomy, beneficence, and non-malificence. In some instances, consequentialism is considered, but these frameworks have their limitations. Their limitations has to do with a consideration for the interpersonal nature of clinical nursing practice on the one hand, and is not always clear on how to judge which consequences are best on the other hand. When principles are in conflict it is not always easy to decide which principle should dominate. Furthermore, these frameworks do not take into account the importance of the interpersonal and emotional element of human experience. On the contrary, decision-making about moral issues in healthcare demands that nurses exercise rational control over emotions. This clearly focuses the attention on the nurse as moral agent and in particular their character. In this article I argue that virtue ethics as an approach, which focus of the character of a person, might provide a more holistic analysis of moral dilemmas in nursing and might facilitate more flexible and creative solutions when combined with other theories of moral decision-making. Advancing this argument, firstly, I provide the central features of virtue ethics. Secondly I describe a story in which a moral dilemma is evident. Lastly I apply virtue ethics as an approach to this moral dilemma and in particular focusing on the virtues inherent in the nurse as moral agent in the story.

  18. Duality, phase structures, and dilemmas in symmetric quantum games

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ichikawa, Tsubasa; Tsutsui, Izumi

    Symmetric quantum games for 2-player, 2-qubit strategies are analyzed in detail by using a scheme in which all pure states in the 2-qubit Hilbert space are utilized for strategies. We consider two different types of symmetric games exemplified by the familiar games, the Battle of the Sexes (BoS) and the Prisoners' Dilemma (PD). These two types of symmetric games are shown to be related by a duality map, which ensures that they share common phase structures with respect to the equilibria of the strategies. We find eight distinct phase structures possible for the symmetric games, which are determined by themore » classical payoff matrices from which the quantum games are defined. We also discuss the possibility of resolving the dilemmas in the classical BoS, PD, and the Stag Hunt (SH) game based on the phase structures obtained in the quantum games. It is observed that quantization cannot resolve the dilemma fully for the BoS, while it generically can for the PD and SH if appropriate correlations for the strategies of the players are provided.« less

  19. Bioethics education in clinical settings: theory and practice of the dilemma method of moral case deliberation.

    PubMed

    Stolper, Margreet; Molewijk, Bert; Widdershoven, Guy

    2016-07-22

    Moral Case Deliberation is a specific form of bioethics education fostering professionals' moral competence in order to deal with their moral questions. So far, few studies focus in detail on Moral Case Deliberation methodologies and their didactic principles. The dilemma method is a structured and frequently used method in Moral Case Deliberation that stimulates methodological reflection and reasoning through a systematic dialogue on an ethical issue experienced in practice. In this paper we present a case-study of a Moral Case Deliberation with the dilemma method in a health care institution for people with an intellectual disability, describing the theoretical background and the practical application of the dilemma method. The dilemma method focuses on moral experiences of participants concerning a concrete dilemma in practice. By an in-depth description of each of the steps of the deliberation process, we elucidate the educational value and didactics of this specific method. The didactics and methodical steps of the dilemma method both supported and structured the dialogical reflection process of the participants. The process shows that the participants learned to recognize the moral dimension of the issue at stake and were able to distinguish various perspectives and reasons in a systematic manner. The facilitator played an important role in the learning process of the participants, by assisting them in focusing on and exploring moral aspects of the case. The reflection and learning process, experienced by the participants, shows competency-based characteristics. The role of the facilitator is that of a Socratic teacher with specific knowledge and skills, fostering reflection, inquiry and dialogue. The specific didactics of the dilemma method is well suited for teaching bioethics in clinical settings. The dilemma method follows an inductive learning approach through a dialogical moral inquiry in which participants develop not only knowledge but also skills

  20. The Changes of Ethical Dilemmas in Palliative Care. A Lesson Learned from Comparison Between 1998 and 2013 in Taiwan.

    PubMed

    Chih, An-Hsuan; Su, Peijen; Hu, Wen-Yu; Yao, Chien-An; Cheng, Shao-Yi; Lin, Yen-Chun; Chiu, Tai-Yuan

    2016-01-01

    The current ethical dilemmas met by healthcare professionals were never compared with those 15 years ago when the palliative care system was newly developing in Taiwan. The aim of the study was to investigate the ethical dilemmas met by palliative care physicians and nurses in 2013 and compare the results with the survey in 1998. This cross-sectional study surveyed 213 physicians and nurses recruited from 9 representative palliative care units across Taiwan in 2013. The compared survey in 1998 studied 102 physicians and nurses from the same palliative care units. All participants took a questionnaire to survey the "frequency" and "difficulty" of 20 frequently encountered ethical dilemmas, which were grouped into 4 domains by factor analysis. The "ethical dilemma" scores were calculated and then compared across 15 years by Student's t tests. A general linear model analysis was used to identify significant factors relating to a high average "ethical dilemma" score in each domain. All of the highest-ranking ethical dilemmas in 2013 were related to insufficient resources. Physicians with less clinical experience had a higher average "ethical dilemma" score in clinical management. Physicians with dissatisfaction in providing palliative care were associated a higher average "ethical dilemma" score in communication. Nurses reported higher "ethical dilemma" scores in all items of resource allocation in 2013. Further analysis confirmed that, in 2013, nurses had a higher average "ethical dilemma" score in resource allocation after adjustment for other relating factors. Palliative care nursing staff in Taiwan are more troubled by ethical dilemmas related to insufficient resources than they were 15 years ago. Training of decision making in nurses under the framework of ethical principles and community palliative care programs may improve the problems. To promote the dignity of terminal cancer patients, long-term fundraising plans are recommended for countries in which the

  1. Ethical Dilemmas on Social Media: Swedish Secondary Teachers' Boundary Management on Facebook

    ERIC Educational Resources Information Center

    Thunman, Elin; Persson, Marcus

    2018-01-01

    With the aim of contributing to the research about the educational use of social media, the paper explores teachers' experiences of ethical dilemmas on Facebook. The paper draws upon focus group interviews with Swedish secondary teachers. Two main categories of ethical dilemmas, related to the border between private and professional, are detected.…

  2. Therapeutic risk management of clinical-legal dilemmas: should it be a core competency?

    PubMed

    Simon, Robert I; Shuman, Daniel W

    2009-01-01

    Therapeutic risk management of clinical-legal dilemmas achieves an optimal alignment between clinical competence and an understanding of legal concerns applicable to psychiatric practice. Understanding how psychiatry and law interact in frequently occurring clinical situations is essential for effective patient care. Successful management of clinical-legal dilemmas also avoids unnecessary, counterproductive defensive practices.

  3. Dilemmas of Leading National Curriculum Reform in a Global Era: A Chinese Perspective

    ERIC Educational Resources Information Center

    Yin, Hongbiao; Lee, John Chi-Kin; Wang, Wenlan

    2014-01-01

    Since the mid-1980s, a global resurgence of large-scale reform in the field of education has been witnessed. Implementing these reforms has created many dilemmas for change leaders. Following a three-year qualitative research project, the present study explores the dilemmas leaders faced during the implementation of the national curriculum reform…

  4. BACTERIAL INHIBITORS IN LAKE WATER

    EPA Science Inventory

    The populations of six bacterial genera fell rapidly after their addition to sterile lake water but not after their addition to buffer. The decline in numbers of two species that were studied further, Klebsiella pneumoniae and Micrococcus flavus, occurred even when the buffer was...

  5. Education in Aboriginal Communities: Dilemmas around Empowerment.

    ERIC Educational Resources Information Center

    Taylor, Donald M.; And Others

    1993-01-01

    Sudden empowerment of Canadian Aboriginal communities has raised many dilemmas concerning community controlled education, including issues related to educational planning and decision making by inexperienced administrators, focusing educational goals on the community versus mainstream society, discontinuities between community and school culture,…

  6. Aging Parents & Dilemmas of Their Children.

    ERIC Educational Resources Information Center

    Smith, Bert Kruger; And Others

    After an opening series of vignettes which describe the frustrations of adults who care for aging and infirm parents, this pamphlet addresses the issue of aging parents and the dilemmas they pose for their children. In particular, it describes a model entitled "As Parents Grow Older" (APGO) that originated as a service for families of…

  7. Project Management Consultancy (PMC) procurement approach: Supplier's evaluation and selection dilemma

    NASA Astrophysics Data System (ADS)

    Nawi, Mohd Nasrun Mohd; Azimi, Mohd Azrulfitri; Pozin, Mohd Affendi Ahmad; Osman, Wan Nadri; Anuar, Herman Shah

    2016-08-01

    Project Management Consultancy (PMC) is part of the management oriented procurement method in which a sole consultant is hired by the client to deal with the contactors in place of the client. Appointing contractors in this method or approach looks to be interesting as client could play a pivotal role in evaluating and selecting the supplier/contractor for the work package. In some cases, client gives the authority for the PMC to hire the supplier/contractor of their choice while in some cases the client is the one who made the decision. This research paper seeks to investigate the dilemma arises from this situation and for the purpose of this research, a real case study was studied to assess the impacts of such dilemma to the performance of the project. Recommendations on how to tackle the dilemma will also be addressed in the later part of this research paper.

  8. Professionalism dilemmas, moral distress and the healthcare student: insights from two online UK-wide questionnaire studies

    PubMed Central

    Monrouxe, Lynn V; Rees, Charlotte E; Dennis, Ian; Wells, Stephanie E

    2015-01-01

    Objective To understand the prevalence of healthcare students’ witnessing or participating in something that they think unethical (professionalism dilemmas) during workplace learning and examine whether differences exist in moral distress intensity resulting from these experiences according to gender and the frequency of occurrence. Design Two cross-sectional online questionnaires of UK medical (study 1) and nursing, dentistry, physiotherapy and pharmacy students (study 2) concerning professionalism dilemmas and subsequent distress for (1) Patient dignity and safety breaches; (2) Valid consent for students’ learning on patients; and (3) Negative workplace behaviours (eg, student abuse). Participants and setting 2397 medical (67.4% female) and 1399 other healthcare students (81.1% female) responded. Main results The most commonly encountered professionalism dilemmas were: student abuse and patient dignity and safety dilemmas. Multinomial and logistic regression identified significant effects for gender and frequency of occurrence. In both studies, men were more likely to classify themselves as experiencing no distress; women were more likely to classify themselves as distressed. Two distinct patterns concerning frequency were apparent: (1) Habituation (study 1): less distress with increased exposure to dilemmas ‘justified’ for learning; (2) Disturbance (studies 1 and 2): more distress with increased exposure to dilemmas that could not be justified. Conclusions Tomorrow's healthcare practitioners learn within a workplace in which they frequently encounter dilemmas resulting in distress. Gender differences could be respondents acting according to gendered expectations (eg, males downplaying distress because they are expected to appear tough). Habituation to dilemmas suggests students might balance patient autonomy and right to dignity with their own needs to learn for future patient benefit. Disturbance contests the ‘accepted’ notion that students become

  9. Influence of bacterial interactions on pneumococcal colonization of the nasopharynx.

    PubMed

    Shak, Joshua R; Vidal, Jorge E; Klugman, Keith P

    2013-03-01

    Streptococcus pneumoniae (the pneumococcus) is a common commensal inhabitant of the nasopharynx and a frequent etiologic agent in serious diseases such as pneumonia, otitis media, bacteremia, and meningitis. Multiple pneumococcal strains can colonize the nasopharynx, which is also home to many other bacterial species. Intraspecies and interspecies interactions influence pneumococcal carriage in important ways. Co-colonization by two or more pneumococcal strains has implications for vaccine serotype replacement, carriage detection, and pneumonia diagnostics. Interactions between the pneumococcus and other bacterial species alter carriage prevalence, modulate virulence, and affect biofilm formation. By examining these interactions, this review highlights how the bacterial ecosystem of the nasopharynx changes the nature and course of pneumococcal carriage. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. Highly heterogeneous bacterial communities associated with the South China Sea reef corals Porites lutea, Galaxea fascicularis and Acropora millepora.

    PubMed

    Li, Jie; Chen, Qi; Zhang, Si; Huang, Hui; Yang, Jian; Tian, Xin-Peng; Long, Li-Juan

    2013-01-01

    Coral harbor diverse and specific bacteria play significant roles in coral holobiont function. Bacteria associated with three of the common and phylogenetically divergent reef-building corals in the South China Sea, Porites lutea, Galaxea fascicularis and Acropora millepora, were investigated using 454 barcoded-pyrosequencing. Three colonies of each species were sampled, and 16S rRNA gene libraries were constructed individually. Analysis of pyrosequencing libraries showed that bacterial communities associated with the three coral species were more diverse than previous estimates based on corals from the Caribbean Sea, Indo-Pacific reefs and the Red Sea. Three candidate phyla, including BRC1, OD1 and SR1, were found for the first time in corals. Bacterial communities were separated into three groups: P. lutea and G. fascicular, A. millepora and seawater. P. lutea and G. fascicular displayed more similar bacterial communities, and bacterial communities associated with A. millepora differed from the other two coral species. The three coral species shared only 22 OTUs, which were distributed in Alphaproteobacteria, Deltaproteobacteria, Gammaproteobacteria, Chloroflexi, Actinobacteria, Acidobacteria and an unclassified bacterial group. The composition of bacterial communities within each colony of each coral species also showed variation. The relatively small common and large specific bacterial communities in these corals implies that bacterial associations may be structured by multiple factors at different scales and that corals may associate with microbes in terms of similar function, rather than identical species.

  11. Teaching the Repeated Prisoner's Dilemma with a Non-Computerised Adaptation of Axelrod's Tournament

    ERIC Educational Resources Information Center

    Dennis, Catherine

    2015-01-01

    Darwin's theory of evolution is explicitly competitive, yet co-operation between individuals is a common phenomenon. The Prisoner's Dilemma model is central to the teaching of the evolution of co-operation. The best-known explorations of the Prisoner's Dilemma are the tournaments run by Robert Axelrod in the 1980s. Aimed at students of biological…

  12. Bacterial biota in reflux esophagitis and Barrett’s esophagus

    PubMed Central

    Pei, Zhiheng; Yang, Liying; Peek, Richard M; Levine, Jr Steven M; Pride, David T; Blaser, Martin J

    2005-01-01

    AIM: To identify the bacterial flora in conditions such as Barrett’s esophagus and reflux esophagitis to determine if they are similar to normal esophageal flora. METHODS: Using broad-range 16S rDNA PCR, esophageal biopsies were examined from 24 patients [9 with normal esophageal mucosa, 12 with gastroesophageal reflux disease (GERD), and 3 with Barrett’s esophagus]. Two separate broad-range PCR reactions were performed for each patient, and the resulting products were cloned. In one patient with Barrett’s esophagus, 99 PCR clones were analyzed. RESULTS: Two separate clones were recovered from each patient (total = 48), representing 24 different species, with 14 species homologous to known bacteria, 5 homologous to unidentified bacteria, and 5 were not homologous (<97% identity) to any known bacterial 16S rDNA sequences. Seventeen species were found in the reflux esophagitis patients, 5 in the Barrett’s esophagus patients, and 10 in normal esophagus patients. Further analysis concentrating on a single biopsy from an individual with Barrett’s esophagus revealed the presence of 21 distinct bacterial species. Members of four phyla were represented, including Bacteroidetes, Firmicutes, Proteobacteria, and Actinobacteria. Microscopic examination of each biopsy demonstrated bacteria in intimate association with the distal esophageal epithelium, suggesting that the presence of these bacteria is not transitory. CONCLUSION: These findings provide evidence for a complex, residential bacterial population in esophageal reflux-related disorders. While much of this biota is present in the normal esophagus, more detailed comparisons may help identify potential disease associations. PMID:16437628

  13. Diversity of Bacterial Communities in Container Habitats of Mosquitoes

    PubMed Central

    Ponnusamy, Loganathan; Xu, Ning; Stav, Gil; Wesson, Dawn M.; Schal, Coby

    2010-01-01

    We investigated the bacterial diversity of microbial communities in water-filled, human-made and natural container habitats of the mosquitoes Aedes aegypti and Aedes albopictus in suburban landscapes of New Orleans, Louisiana in 2003. We collected water samples from three classes of containers, including tires (n=12), cemetery urns (n=23), and miscellaneous containers that included two tree holes (n=19). Total genomic DNA was extracted from water samples, and 16S ribosomal DNA fragments (operational taxonomic units, OTUs) were amplified by PCR and separated by denaturing gradient gel electrophoresis (DGGE). The bacterial communities in containers represented diverse DGGE-DNA banding patterns that were not related to the class of container or to the local spatial distribution of containers. Mean richness and evenness of OTUs were highest in water samples from tires. Bacterial phylotypes were identified by comparative sequence analysis of 90 16S rDNA DGGE band amplicons. The majority of sequences were placed in five major taxa: Alpha-, Beta- and Gammaproteobacteria, Actinobacteria, Bacteroidetes, Cyanobacteria, Firmicutes, and an unclassified group; Proteobacteria and Bacteroidetes were the predominant heterotrophic bacteria in containers. The bacterial communities in human-made containers consisted mainly of undescribed species, and a phylogenetic analysis based on 16S rRNA sequences suggested that species composition was independent of both container type and the spatial distribution of containers. Comparative PCR-based, cultivation-independent rRNA surveys of microbial communities associated with mosquito habitats can provide significant insight into community organization and dynamics of bacterial species. PMID:18373113

  14. Cognition and norms: toward a developmental account of moral agency in social dilemmas.

    PubMed

    Meyer, Leandro F F; Braga, Marcelo J

    2014-01-01

    Most recent developments in the study of social dilemmas give an increasing amount of attention to cognition, belief systems, valuations, and language. However, developments in this field operate almost entirely under epistemological assumptions which only recognize the instrumental form of rationality and deny that "value judgments" or "moral questions" have cognitive content. This standpoint erodes the moral aspect of the choice situation and obstructs acknowledgment of the links connecting cognition, inner growth, and moral reasoning, and the significance of such links in reaching cooperative solutions to many social dilemmas. Concurrently, this standpoint places the role of communication and mutual understanding in promoting cooperation in morally relevant conflicts of action in a rather mysterious situation. This paper draws on Habermas's critique of instrumental action, and on the most recent developments in institutional and behavioral economics with a view to enhancing our knowledge of the interventions used to cope with social dilemmas. We conclude the paper with a brief presentation of a research strategy for examining the capacity of alternative developmental models to predict dissimilar choices under similar incentive conditions in social dilemmas.

  15. Statistical physics of the spatial Prisoner's Dilemma with memory-aware agents

    NASA Astrophysics Data System (ADS)

    Javarone, Marco Alberto

    2016-02-01

    We introduce an analytical model to study the evolution towards equilibrium in spatial games, with `memory-aware' agents, i.e., agents that accumulate their payoff over time. In particular, we focus our attention on the spatial Prisoner's Dilemma, as it constitutes an emblematic example of a game whose Nash equilibrium is defection. Previous investigations showed that, under opportune conditions, it is possible to reach, in the evolutionary Prisoner's Dilemma, an equilibrium of cooperation. Notably, it seems that mechanisms like motion may lead a population to become cooperative. In the proposed model, we map agents to particles of a gas so that, on varying the system temperature, they randomly move. In doing so, we are able to identify a relation between the temperature and the final equilibrium of the population, explaining how it is possible to break the classical Nash equilibrium in the spatial Prisoner's Dilemma when considering agents able to increase their payoff over time. Moreover, we introduce a formalism to study order-disorder phase transitions in these dynamics. As result, we highlight that the proposed model allows to explain analytically how a population, whose interactions are based on the Prisoner's Dilemma, can reach an equilibrium far from the expected one; opening also the way to define a direct link between evolutionary game theory and statistical physics.

  16. Profile and Fate of Bacterial Pathogens in Sewage Treatment Plants Revealed by High-Throughput Metagenomic Approach.

    PubMed

    Li, Bing; Ju, Feng; Cai, Lin; Zhang, Tong

    2015-09-01

    The broad-spectrum profile of bacterial pathogens and their fate in sewage treatment plants (STPs) were investigated using high-throughput sequencing based metagenomic approach. This novel approach could provide a united platform to standardize bacterial pathogen detection and realize direct comparison among different samples. Totally, 113 bacterial pathogen species were detected in eight samples including influent, effluent, activated sludge (AS), biofilm, and anaerobic digestion sludge with the abundances ranging from 0.000095% to 4.89%. Among these 113 bacterial pathogens, 79 species were reported in STPs for the first time. Specially, compared to AS in bulk mixed liquor, more pathogen species and higher total abundance were detected in upper foaming layer of AS. This suggests that the foaming layer of AS might impose more threat to onsite workers and citizens in the surrounding areas of STPs because pathogens in foaming layer are easily transferred into air and cause possible infections. The high removal efficiency (98.0%) of total bacterial pathogens suggests that AS treatment process is effective to remove most bacterial pathogens. Remarkable similarities of bacterial pathogen compositions between influent and human gut indicated that bacterial pathogen profiles in influents could well reflect the average bacterial pathogen communities of urban resident guts within the STP catchment area.

  17. Communal range defence in primates as a public goods dilemma.

    PubMed

    Willems, Erik P; Arseneau, T Jean M; Schleuning, Xenia; van Schaik, Carel P

    2015-12-05

    Classic socio-ecological theory holds that the occurrence of aggressive range defence is primarily driven by ecological incentives, most notably by the economic defendability of an area or the resources it contains. While this ecological cost-benefit framework has great explanatory power in solitary or pair-living species, comparative work on group-living primates has always found economic defendability to be a necessary, but not sufficient condition to account for the distribution of effective range defence across the taxon. This mismatch between theory and observation has recently been ascribed to a collective action problem among group members in, what is more informatively viewed as, a public goods dilemma: mounting effective defence of a communal range against intrusions by outgroup conspecifics. We here further develop this framework, and report on analyses at three levels of biological organization: across species, across populations within a single lineage and across groups and individuals within a single population. We find that communal range defence in primates very rarely involves collective action sensu stricto and that it is best interpreted as the outcome of opportunistic and strategic individual-level decisions. Whether the public good of a defended communal range is produced by solitary, joint or collective action is thus the outcome of the interplay between the unique characteristics of each individual, local and current socio-ecological conditions, and fundamental life-history traits of the species. © 2015 The Author(s).

  18. Bacterial respiration of arsenic and selenium

    USGS Publications Warehouse

    Stolz, J.F.; Oremland, R.S.

    1999-01-01

    Oxyanions of arsenic and selenium can be used in microbial anaerobic respiration as terminal electron acceptors. The detection of arsenate and selenate respiring bacteria in numerous pristine and contaminated environments and their rapid appearance in enrichment culture suggest that they are widespread and metabolically active in nature. Although the bacterial species that have been isolated and characterized are still few in number, they are scattered throughout the bacterial domain and include Gram- positive bacteria, beta, gamma and epsilon Proteobacteria and the sole member of a deeply branching lineage of the bacteria, Chrysiogenes arsenatus. The oxidation of a number of organic substrates (i.e. acetate, lactate, pyruvate, glycerol, ethanol) or hydrogen can be coupled to the reduction of arsenate and selenate, but the actual donor used varies from species to species. Both periplasmic and membrane-associated arsenate and selenate reductases have been characterized. Although the number of subunits and molecular masses differs, they all contain molybdenum. The extent of the environmental impact on the transformation and mobilization of arsenic and selenium by microbial dissimilatory processes is only now being fully appreciated.

  19. Modern Dilemmas - Science (World History Series).

    ERIC Educational Resources Information Center

    Montgomery County Public Schools, Rockville, MD.

    The publication, referred to as a unit on "Modern Dilemmas," was completed in 1969 and is part of a Modern World History pilot project integrating areas of art, literature, philosophy, and science into the social studies curriculum. The unit seeks to explore all of the facets of science as part of man's search for meaning, but because of time…

  20. On the core bacterial flora of Ixodes persulcatus (Taiga tick).

    PubMed

    Sui, Shuo; Yang, Yu; Sun, Yi; Wang, Xumin; Wang, Guoliang; Shan, Guangle; Wang, Jiancheng; Yu, Jun

    2017-01-01

    Ixodes persulcatus is a predominant hard tick species that transmits a wide range of human and animal pathogens. Since bacterial flora of the tick dwelling in the wild always vary according to their hosts and the environment, it is highly desirable that species-associated microbiomes are fully determined by using next-generation sequencing and based on comparative metagenomics. Here, we examine such metagenomic changes of I. persulcatus starting with samples collected from the wild ticks and followed by the reared animals under pathogen-free laboratory conditions over multiple generations. Based on high-coverage genomic sequences from three experimental groups-wild, reared for a single generation or R1, and reared for eight generations or R8 -we identify the core bacterial flora of I. persulcatus, which contains 70 species that belong to 69 genera of 8 phyla; such a core is from the R8 group, which is reduced from 4625 species belonging to 1153 genera of 29 phyla in the wild group. Our study provides a novel example of tick core bacterial flora acquired based on wild-to-reared comparison, which paves a way for future research on tick metagenomics and tick-borne disease pandemics.

  1. On the core bacterial flora of Ixodes persulcatus (Taiga tick)

    PubMed Central

    Sun, Yi; Wang, Xumin; Wang, Guoliang; Shan, Guangle; Wang, Jiancheng; Yu, Jun

    2017-01-01

    Ixodes persulcatus is a predominant hard tick species that transmits a wide range of human and animal pathogens. Since bacterial flora of the tick dwelling in the wild always vary according to their hosts and the environment, it is highly desirable that species-associated microbiomes are fully determined by using next-generation sequencing and based on comparative metagenomics. Here, we examine such metagenomic changes of I. persulcatus starting with samples collected from the wild ticks and followed by the reared animals under pathogen-free laboratory conditions over multiple generations. Based on high-coverage genomic sequences from three experimental groups–wild, reared for a single generation or R1, and reared for eight generations or R8 –we identify the core bacterial flora of I. persulcatus, which contains 70 species that belong to 69 genera of 8 phyla; such a core is from the R8 group, which is reduced from 4625 species belonging to 1153 genera of 29 phyla in the wild group. Our study provides a novel example of tick core bacterial flora acquired based on wild-to-reared comparison, which paves a way for future research on tick metagenomics and tick-borne disease pandemics. PMID:28692666

  2. Bacterial pericarditis in a cat.

    PubMed

    LeBlanc, Nicole; Scollan, Katherine F

    2015-01-01

    A 4-year-old male neutered domestic shorthair cat was presented to the Oregon State University cardiology service for suspected pericardial effusion. Cardiac tamponade was documented and pericardiocentesis yielded purulent fluid with cytologic results supportive of bacterial pericarditis. The microbial population consisted of Pasteurella multocida, Actinomyces canis, Fusobacterium and Bacteroides species. Conservative management was elected consisting of intravenous antibiotic therapy with ampicillin sodium/sulbactam sodium and metronidazole for 48 h followed by 4 weeks of oral antibiotics. Re-examination 3 months after the initial incident indicated no recurrence of effusion and the cat remained free of clinical signs 2 years after presentation. Bacterial pericarditis is a rare cause of pericardial effusion in cats. Growth of P multocida, A canis, Fusobacterium and Bacteroides species has not previously been documented in feline septic pericarditis. Conservative management with broad-spectrum antibiotics may be considered when further diagnostic imaging or exploratory surgery to search for a primary nidus of infection is not feasible or elected.

  3. Reading Dilemmas in a Foreign Language Reduces Both Deontological and Utilitarian Response Tendencies

    ERIC Educational Resources Information Center

    Muda, Rafal; Niszczota, Pawel; Bialek, Michal; Conway, Paul

    2018-01-01

    Moral dilemmas entail deciding whether to cause harm to maximize overall outcomes, such as killing 1 person to save 5. Past work has demonstrated that people are more willing to accept causing such outcome-maximizing harm when they read dilemmas in a foreign language they speak rather than their native language. Presumably this effect is due to…

  4. Perceptions of the Dilemma--Order versus Freedom at Managing Faculty: A Literature Review

    ERIC Educational Resources Information Center

    Karaferye, Figen; Agaoglu, Esmahan

    2017-01-01

    This study aims to examine the perceptions of the middle management (deans and heads of departments) and academicians on the dilemma order versus freedom at faculty management. It discusses how this dilemma is seen at an operational level and how it can be managed at university where both parties--with a managerial role or not--are…

  5. Prevalence of gastrointestinal bacterial pathogens in a population of zoo animals.

    PubMed

    Stirling, J; Griffith, M; Blair, I; Cormican, M; Dooley, J S G; Goldsmith, C E; Glover, S G; Loughrey, A; Lowery, C J; Matsuda, M; McClurg, R; McCorry, K; McDowell, D; McMahon, A; Cherie Millar, B; Nagano, Y; Rao, J R; Rooney, P J; Smyth, M; Snelling, W J; Xu, J; Moore, J E

    2008-04-01

    Faecal prevalence of gastrointestinal bacterial pathogens, including Campylobacter, Escherichia coli O157:H7, Salmonella, Shigella, Yersinia, as well as Arcobacter, were examined in 317 faecal specimens from 44 animal species in Belfast Zoological Gardens, during July-September 2006. Thermophilic campylobacters including Campylobacter jejuni, Campylobacter coli and Campylobacter lari, were the most frequently isolated pathogens, where members of this genus were isolated from 11 animal species (11 of 44; 25%). Yersinia spp. were isolated from seven animal species (seven of 44; 15.9%) and included, Yersinia enterocolitica (five of seven isolates; 71.4%) and one isolate each of Yersinia frederiksenii and Yersinia kristensenii. Only one isolate of Salmonella was obtained throughout the entire study, which was an isolate of Salmonella dublin (O 1,9,12: H g, p), originating from tiger faeces after enrichment. None of the animal species found in public contact areas of the zoo were positive for any gastrointestinal bacterial pathogens. Also, water from the lake in the centre of the grounds, was examined for the same bacterial pathogens and was found to contain C. jejuni. This study is the first report on the isolation of a number of important bacterial pathogens from a variety of novel host species, C. jejuni from the red kangaroo (Macropus rufus), C. lari from a maned wolf (Chrysocyon brachyurus), Y. kristensenii from a vicugna (Vicugna vicugna) and Y. enterocolitica from a maned wolf and red panda (Ailurus fulgens). In conclusion, this study demonstrated that the faeces of animals in public contact areas of the zoo were not positive for the bacterial gastrointestinal pathogens examined. This is reassuring for the public health of visitors, particularly children, who enjoy this educational and recreational resource.

  6. De-Marginalizing Science in the Elementary Classroom by Coaching Teachers to Address Perceived Dilemmas

    ERIC Educational Resources Information Center

    Berg, Alissa; Mensah, Felicia Moore

    2014-01-01

    This study identifies and explores the dilemmas experienced by three first-grade teachers in teaching elementary school science. The impact of coaching and teachers' career stages on how teachers reconcile their dilemmas was examined. Results of this comparative case study indicate teachers perceived tensions between focusing instructional…

  7. What makes moral dilemma judgments "utilitarian" or "deontological"?

    PubMed

    Gawronski, Bertram; Beer, Jennifer S

    2017-12-01

    The distinction between utilitarianism and deontology has become a prevailing framework for conceptualizing moral judgment. According to the principle of utilitarianism, the morality of an action depends on its outcomes. In contrast, the principle of deontology states that the morality of an action depends on its consistency with moral norms. To identify the processes underlying utilitarian and deontological judgments, research in psychology and neuroscience has investigated responses to moral dilemmas that pit one principle against the other (e.g., trolley dilemma). However, the interpretation of responses in this paradigm is ambiguous, because the defining aspects of utilitarianism and deontology, outcomes and norms, are not manipulated. We illustrate how this shortcoming distorts interpretations of empirical findings and describe an alternative approach that overcomes the limitations of the traditional paradigm.

  8. Leadership styles in ethical dilemmas when head nurses make decisions.

    PubMed

    Zydziunaite, V; Lepaite, D; Suominen, T

    2013-06-01

    The overlooked aspect in Lithuania is the dearth of leaders among head nurses, who bear the responsibility for decisions in ethical dilemmas. Understanding the application of leadership styles is fundamental to ensuring head nurses' abilities to influence outcomes for healthcare providers and patients. To identify the leadership styles applied by head nurses in decision making in ethical dilemmas on hospital wards. The data were collected by questionnaires completed by head nurses (n = 278) working in five major state-funded hospitals in each of the five regions of Lithuania. The data were analysed using SPSS 16.0, calculating descriptive statistics and analysis of variance. Head nurses apply democratic, affiliative, transformational and sustainable leadership styles when resolving ethical dilemmas. The application of leadership styles is associated not only with specific situations, but also with certain background factors, such as years of experience in a head nurse's position, ward specialization and the incidence of ethical dilemmas. Nurses having been in a head nurse's position over 10 years use primitive leadership styles, notably bureaucratic leadership, more often than do those head nurses with only a few years of experience in such a position. The results highlight the need for head nurses to reflect on their practices and to find new ways of learning from practice, colleagues and patients. Head nurses' managerial decisions due to their 'executive power' can turn into a new state-of-the-art leadership in nursing. © 2013 The Authors. International Nursing Review © 2013 International Council of Nurses.

  9. Hierarchical prisoner’s dilemma in hierarchical game for resource competition

    NASA Astrophysics Data System (ADS)

    Fujimoto, Yuma; Sagawa, Takahiro; Kaneko, Kunihiko

    2017-07-01

    Dilemmas in cooperation are one of the major concerns in game theory. In a public goods game, each individual cooperates by paying a cost or defecting without paying it, and receives a reward from the group out of the collected cost. Thus, defecting is beneficial for each individual, while cooperation is beneficial for the group. Now, groups (say, countries) consisting of individuals also play games. To study such a multi-level game, we introduce a hierarchical game in which multiple groups compete for limited resources by utilizing the collected cost in each group, where the power to appropriate resources increases with the population of the group. Analyzing this hierarchical game, we found a hierarchical prisoner’s dilemma, in which groups choose the defecting policy (say, armament) as a Nash strategy to optimize each group’s benefit, while cooperation optimizes the total benefit. On the other hand, for each individual, refusing to pay the cost (say, tax) is a Nash strategy, which turns out to be a cooperation policy for the group, thus leading to a hierarchical dilemma. Here the group reward increases with the group size. However, we find that there exists an optimal group size that maximizes the individual payoff. Furthermore, when the population asymmetry between two groups is large, the smaller group will choose a cooperation policy (say, disarmament) to avoid excessive response from the larger group, and the prisoner’s dilemma between the groups is resolved. Accordingly, the relevance of this hierarchical game on policy selection in society and the optimal size of human or animal groups are discussed.

  10. Taiwanese medical students' narratives of intercultural professionalism dilemmas: exploring tensions between Western medicine and Taiwanese culture.

    PubMed

    Ho, Ming-Jung; Gosselin, Katherine; Chandratilake, Madawa; Monrouxe, Lynn V; Rees, Charlotte E

    2017-05-01

    In an era of globalization, cultural competence is necessary for the provision of quality healthcare. Although this topic has been well explored in non-Western cultures within Western contexts, the authors explore how Taiwanese medical students trained in Western medicine address intercultural professionalism dilemmas related to tensions between Western medicine and Taiwanese culture. A narrative interview method was employed with 64 Taiwanese medical students to collect narratives of professionalism dilemmas. Noting the prominence of culture in students' narratives, we explored this theme further using secondary analysis, identifying tensions between Western medicine and Taiwanese culture and categorizing students' intercultural professionalism dilemmas according to Friedman and Berthoin Antal's 'intercultural competence' framework: involving combinations of advocacy (i.e., championing one's own culture) and inquiry (i.e., exploring one's own and others' cultures). One or more intercultural dilemmas were identified in nearly half of students' professionalism dilemma narratives. Qualitative themes included: family relations, local policy, end-of-life care, traditional medicine, gender relations and Taiwanese language. Of the 62 narratives with sufficient detail for further analysis, the majority demonstrated the 'suboptimal' low advocacy/low inquiry approach (i.e., withdrawal or inaction), while very few demonstrated the 'ideal' high advocacy/high inquiry approach (i.e., generating mutual understanding, so 'intercultural competence'). Though nearly half of students' professionalism narratives concerned intercultural dilemmas, most narratives represented disengagement from intercultural dilemmas, highlighting a possible need for more attention on intercultural competence training in Taiwan. The advocacy/inquiry framework may help educators to address similar disconnects between Western medicine and non-Western cultures in other contexts.

  11. Bacterial diversity in permanently cold and alkaline ikaite columns from Greenland.

    PubMed

    Schmidt, Mariane; Priemé, Anders; Stougaard, Peter

    2006-12-01

    Bacterial diversity in alkaline (pH 10.4) and permanently cold (4 degrees C) ikaite tufa columns from the Ikka Fjord, SW Greenland, was investigated using growth characterization of cultured bacterial isolates with Terminal-restriction fragment length polymorphism (T-RFLP) and sequence analysis of bacterial 16S rRNA gene fragments. More than 200 bacterial isolates were characterized with respect to pH and temperature tolerance, and it was shown that the majority were cold-active alkaliphiles. T-RFLP analysis revealed distinct bacterial communities in different fractions of three ikaite columns, and, along with sequence analysis, it showed the presence of rich and diverse bacterial communities. Rarefaction analysis showed that the 109 sequenced clones in the 16S rRNA gene library represented between 25 and 65% of the predicted species richness in the three ikaite columns investigated. Phylogenetic analysis of the 16S rRNA gene sequences revealed many sequences with similarity to alkaliphilic or psychrophilic bacteria, and showed that 33% of the cloned sequences and 33% of the cultured bacteria showed less than 97% sequence identity to known sequences in databases, and may therefore represent yet unknown species.

  12. Bacterial Community Succession in Pine-Wood Decomposition.

    PubMed

    Kielak, Anna M; Scheublin, Tanja R; Mendes, Lucas W; van Veen, Johannes A; Kuramae, Eiko E

    2016-01-01

    Though bacteria and fungi are common inhabitants of decaying wood, little is known about the relationship between bacterial and fungal community dynamics during natural wood decay. Based on previous studies involving inoculated wood blocks, strong fungal selection on bacteria abundance and community composition was expected to occur during natural wood decay. Here, we focused on bacterial and fungal community compositions in pine wood samples collected from dead trees in different stages of decomposition. We showed that bacterial communities undergo less drastic changes than fungal communities during wood decay. Furthermore, we found that bacterial community assembly was a stochastic process at initial stage of wood decay and became more deterministic in later stages, likely due to environmental factors. Moreover, composition of bacterial communities did not respond to the changes in the major fungal species present in the wood but rather to the stage of decay reflected by the wood density. We concluded that the shifts in the bacterial communities were a result of the changes in wood properties during decomposition and largely independent of the composition of the wood-decaying fungal communities.

  13. Bacterial Community Succession in Pine-Wood Decomposition

    PubMed Central

    Kielak, Anna M.; Scheublin, Tanja R.; Mendes, Lucas W.; van Veen, Johannes A.; Kuramae, Eiko E.

    2016-01-01

    Though bacteria and fungi are common inhabitants of decaying wood, little is known about the relationship between bacterial and fungal community dynamics during natural wood decay. Based on previous studies involving inoculated wood blocks, strong fungal selection on bacteria abundance and community composition was expected to occur during natural wood decay. Here, we focused on bacterial and fungal community compositions in pine wood samples collected from dead trees in different stages of decomposition. We showed that bacterial communities undergo less drastic changes than fungal communities during wood decay. Furthermore, we found that bacterial community assembly was a stochastic process at initial stage of wood decay and became more deterministic in later stages, likely due to environmental factors. Moreover, composition of bacterial communities did not respond to the changes in the major fungal species present in the wood but rather to the stage of decay reflected by the wood density. We concluded that the shifts in the bacterial communities were a result of the changes in wood properties during decomposition and largely independent of the composition of the wood-decaying fungal communities. PMID:26973611

  14. Gender Dysphoria: The Therapist's Dilemma--The Client's Choice.

    ERIC Educational Resources Information Center

    Sherebrin, Hannah

    1996-01-01

    Therapist's role and dilemmas faced in treating a gender dysphoric client are discussed. Examines ethical and moral issues relating to transsexualism and discusses the appropriateness of art therapy as a treatment for transsexual clients. (SNR)

  15. Cultivable Bacterial Microbiota of Northern Bobwhite (Colinus virginianus): A New Reservoir of Antimicrobial Resistance?

    PubMed Central

    Su, Hongwen; McKelvey, Jessica; Rollins, Dale; Zhang, Michael; Brightsmith, Donald J.; Derr, James; Zhang, Shuping

    2014-01-01

    The northern bobwhite (Colinus virginianus) is an ecologically and economically important avian species. At the present time, little is known about the microbial communities associated with these birds. As the first step to create a quail microbiology knowledge base, the current study conducted an inventory of cultivable quail tracheal, crop, cecal, and cloacal microbiota and associated antimicrobial resistance using a combined bacteriology and DNA sequencing approach. A total of 414 morphologically unique bacterial colonies were selected from nonselective aerobic and anaerobic cultures, as well as selective and enrichment cultures. Analysis of the first 500-bp 16S rRNA gene sequences in conjunction with biochemical identifications revealed 190 non-redundant species-level taxonomic units, representing 160 known bacterial species and 30 novel species. The bacterial species were classified into 4 phyla, 14 orders, 37 families, and 59 or more genera. Firmicutes was the most commonly encountered phylum (57%) followed by Actinobacteria (24%), Proteobacteria (17%) and Bacteroidetes (0.02%). Extensive diversity in the species composition of quail microbiota was observed among individual birds and anatomical locations. Quail microbiota harbored several opportunistic pathogens, such as E. coli and Ps. aeruginosa, as well as human commensal organisms, including Neisseria species. Phenotypic characterization of selected bacterial species demonstrated a high prevalence of resistance to the following classes of antimicrobials: phenicol, macrolide, lincosamide, quinolone, and sulphate. Data from the current investigation warrant further investigation on the source, transmission, pathology, and control of antimicrobial resistance in wild quail populations. PMID:24937705

  16. The animal food supplement sepiolite promotes a direct horizontal transfer of antibiotic resistance plasmids between bacterial species.

    PubMed

    Rodríguez-Beltrán, Jerónimo; Rodríguez-Rojas, Alexandro; Yubero, Elva; Blázquez, Jesús

    2013-06-01

    Animal fodder is routinely complemented with antibiotics together with other food supplements to improve growth. For instance, sepiolite is currently used as a dietary coadjuvant in animal feed, as it increases animal growth parameters and improves meat and derived final product quality. This type of food additive has so far been considered innocuous for the development and spread of antibiotic resistance. In this study, we demonstrate that sepiolite promotes the direct horizontal transfer of antibiotic resistance plasmids between bacterial species. The conditions needed for plasmid transfer (sepiolite and friction forces) occur in the digestive tracts of farm animals, which routinely receive sepiolite as a food additive. Furthermore, this effect may be aggravated by the use of antibiotics supplied as growth promoters.

  17. Ethical Dilemmas in Office Practice: Physician Response and Rationale

    PubMed Central

    Secundy, Marian Gray

    1985-01-01

    A survey of black and white family physicians in the District of Columbia is described. The survey provides insight into decision-making processes and the ability to recognize ethical dilemmas in medical practice. Comments were elicited to hypothetical case vignettes typical of ethical conflict in office practice. Findings note physician ability to recognize ethical dilemmas in day-to-day aspects of medical practice. Methods of decision making and rationale for decisions made, however, appear to be inconsistent, nonuniversal, and individualistic without evidence of specific models or criteria. No significant differences were noted between black and white physicians. The need in physician training for clarification and development of criteria is evident. PMID:4078929

  18. Examination of ethical dilemmas experienced by adult intensive care unit nurses in physical restraint practices.

    PubMed

    Yönt, Gülendam Hakverdioğlu; Korhan, Esra Akin; Dizer, Berna; Gümüş, Fatma; Koyuncu, Rukiye

    2014-01-01

    Nurses are more likely to face the dilemma of whether to resort to physical restraints or not and have a hard time making that decision. This is a descriptive study. A total of 55 nurses participated in the research. For data collection, a question form developed by researchers to determine perceptions of ethical dilemmas by nurses in the application of physical restraint was used. A descriptive analysis was made by calculating the mean, standard deviation, and maximum and minimum values. The nurses expressed (36.4%) having difficulty in deciding to use physical restraint. Nurses reported that they experience ethical dilemmas mainly in relation to the ethic principles of nonmaleficence, beneficence, and convenience. We have concluded that majority of nurses working in critical care units apply physical restraint to patients, although they are facing ethical dilemmas concerning harm and benefit principles during the application.

  19. Dilemmas and Deliberations in Reflexive Ethnographic Research

    ERIC Educational Resources Information Center

    Robinson, Janean Valerie

    2014-01-01

    This paper traces insights into the challenges and dilemmas experienced whilst researching students' interpretations and understandings of the Behaviour Management in Schools policy in Western Australia. Journal records, supported by student transcripts, are woven together in a reflexive ethnographic journey--from the beginning phase of searching…

  20. Experienced Speech-Language Pathologists' Responses to Ethical Dilemmas: An Integrated Approach to Ethical Reasoning

    ERIC Educational Resources Information Center

    Kenny, Belinda; Lincoln, Michelle; Balandin, Susan

    2010-01-01

    Purpose: To investigate the approaches of experienced speech-language pathologists (SLPs) to ethical reasoning and the processes they use to resolve ethical dilemmas. Method: Ten experienced SLPs participated in in-depth interviews. A narrative approach was used to guide participants' descriptions of how they resolved ethical dilemmas. Individual…

  1. Bacterial Flora Changes in Conjunctiva of Rats with Streptozotocin-Induced Type I Diabetes.

    PubMed

    Yang, Chao; Fei, Yuda; Qin, Yali; Luo, Dan; Yang, Shufei; Kou, Xinyun; Zi, Yingxin; Deng, Tingting; Jin, Ming

    2015-01-01

    The microbiota of both humans and animals plays an important role in their health and the development of disease. Therefore, the bacterial flora of the conjunctiva may also be associated with some diseases. However, there are no reports on the alteration of bacterial flora in conjunctiva of diabetic rats in the literature. Therefore, we investigated the changes in bacterial flora in bulbar conjunctiva of rats with streptozotocin (STZ)-induced type I diabetes. A high dose of STZ (60 mg/kg, i.p.) was injected into Sprague-Dawley (SD) rats to induce type I diabetes mellitus (T1DM). The diabetic rats were raised in the animal laboratory and at 8 months post-injection of STZ swab samples were taken from the bulbar conjunctiva for cultivation of aerobic bacteria. The bacterial isolates were identified by Gram staining and biochemical features. The identified bacteria from both diabetic and healthy rats were then compared. The diabetic and healthy rats had different bacterial flora present in their bulbar conjunctiva. In total, 10 and 8 bacterial species were found in the STZ and control groups, respectively, with only three species (Enterococcus faecium, Enterococcus gallinarum and Escherichia coli) shared between the two groups. Gram-positive bacteria were common in both groups and the most abundant was Enterococcus faecium. However, after the development of T1DM, the bacterial flora in the rat bulbar conjunctiva changed considerably, with a reduced complexity evident. STZ-induced diabetes caused alterations of bacterial flora in the bulbar conjunctiva in rats, with some bacterial species disappearing and others emerging. Our results indicate that the conjunctival bacterial flora in diabetic humans should be surveyed for potential diagnostic markers or countermeasures to prevent eye infections in T1DM patients.

  2. Bacterial Flora Changes in Conjunctiva of Rats with Streptozotocin-Induced Type I Diabetes

    PubMed Central

    Qin, Yali; Luo, Dan; Yang, Shufei; Kou, Xinyun; Zi, Yingxin; Deng, Tingting; Jin, Ming

    2015-01-01

    Background The microbiota of both humans and animals plays an important role in their health and the development of disease. Therefore, the bacterial flora of the conjunctiva may also be associated with some diseases. However, there are no reports on the alteration of bacterial flora in conjunctiva of diabetic rats in the literature. Therefore, we investigated the changes in bacterial flora in bulbar conjunctiva of rats with streptozotocin (STZ)-induced type I diabetes. Methods A high dose of STZ (60 mg/kg, i.p.) was injected into Sprague-Dawley (SD) rats to induce type I diabetes mellitus (T1DM). The diabetic rats were raised in the animal laboratory and at 8 months post-injection of STZ swab samples were taken from the bulbar conjunctiva for cultivation of aerobic bacteria. The bacterial isolates were identified by Gram staining and biochemical features. The identified bacteria from both diabetic and healthy rats were then compared. Results The diabetic and healthy rats had different bacterial flora present in their bulbar conjunctiva. In total, 10 and 8 bacterial species were found in the STZ and control groups, respectively, with only three species (Enterococcus faecium, Enterococcus gallinarum and Escherichia coli) shared between the two groups. Gram-positive bacteria were common in both groups and the most abundant was Enterococcus faecium. However, after the development of T1DM, the bacterial flora in the rat bulbar conjunctiva changed considerably, with a reduced complexity evident. Conclusions STZ-induced diabetes caused alterations of bacterial flora in the bulbar conjunctiva in rats, with some bacterial species disappearing and others emerging. Our results indicate that the conjunctival bacterial flora in diabetic humans should be surveyed for potential diagnostic markers or countermeasures to prevent eye infections in T1DM patients. PMID:26176548

  3. Understanding institutional stakeholders’ perspectives on multidrug-resistant bacterial organism at the end of life: a qualitative study

    PubMed Central

    Heckel, Maria; Herbst, Franziska A; Adelhardt, Thomas; Tiedtke, Johanna M; Sturm, Alexander; Stiel, Stephanie; Ostgathe, Christoph

    2017-01-01

    Background Information lacks about institutional stakeholders’ perspectives on management approaches of multidrug-resistant bacterial organism in end-of-life situations. The term “institutional stakeholder” includes persons in leading positions with responsibility in hospitals’ multidrug-resistant bacterial organism management. They have great influence on how strategies on multidrug-resistant bacterial organism management approaches in institutions of the public health system are designed. This study targeted institutional stakeholders’ individual perspectives on multidrug-resistant bacterial organism colonization or infection and isolation measures at the end of life. Methods Between March and December 2014, institutional stakeholders of two study centers, a German palliative care unit and a geriatric ward, were queried in semistructured interviews. Interviews were audiotaped, transcribed verbatim, and analyzed qualitatively with the aid of the software MAXQDA for qualitative data analysis using principles of Grounded Theory. In addition, two external stakeholders were interviewed to enrich data. Results Key issues addressed by institutional stakeholders (N=18) were the relevance of multidrug-resistant bacterial organism in palliative and geriatric care, contradictions between hygiene principles and patients’ and family caregivers’ needs and divergence from standards, frame conditions, and reflections on standardization of multidrug-resistant bacterial organism end-of-life care procedures. Results show that institutional stakeholders face a dilemma between their responsibility in protecting third persons and ensuring patients’ quality of life. Until further empirical evidence establishes a clear multidrug-resistant bacterial organism management approach in end-of-life care, stakeholders suggest a case-based approach. Conclusion The institutional stakeholders’ perspectives and their suggestion of a case-based approach advance the development

  4. Understanding institutional stakeholders' perspectives on multidrug-resistant bacterial organism at the end of life: a qualitative study.

    PubMed

    Heckel, Maria; Herbst, Franziska A; Adelhardt, Thomas; Tiedtke, Johanna M; Sturm, Alexander; Stiel, Stephanie; Ostgathe, Christoph

    2017-01-01

    Information lacks about institutional stakeholders' perspectives on management approaches of multidrug-resistant bacterial organism in end-of-life situations. The term "institutional stakeholder" includes persons in leading positions with responsibility in hospitals' multidrug-resistant bacterial organism management. They have great influence on how strategies on multidrug-resistant bacterial organism management approaches in institutions of the public health system are designed. This study targeted institutional stakeholders' individual perspectives on multidrug-resistant bacterial organism colonization or infection and isolation measures at the end of life. Between March and December 2014, institutional stakeholders of two study centers, a German palliative care unit and a geriatric ward, were queried in semistructured interviews. Interviews were audiotaped, transcribed verbatim, and analyzed qualitatively with the aid of the software MAXQDA for qualitative data analysis using principles of Grounded Theory. In addition, two external stakeholders were interviewed to enrich data. Key issues addressed by institutional stakeholders (N=18) were the relevance of multidrug-resistant bacterial organism in palliative and geriatric care, contradictions between hygiene principles and patients' and family caregivers' needs and divergence from standards, frame conditions, and reflections on standardization of multidrug-resistant bacterial organism end-of-life care procedures. Results show that institutional stakeholders face a dilemma between their responsibility in protecting third persons and ensuring patients' quality of life. Until further empirical evidence establishes a clear multidrug-resistant bacterial organism management approach in end-of-life care, stakeholders suggest a case-based approach. The institutional stakeholders' perspectives and their suggestion of a case-based approach advance the development process of a patient-, family-, staff-, and institutional

  5. Exploring the plant-associated bacterial communities in Medicago sativa L

    PubMed Central

    2012-01-01

    Background Plant-associated bacterial communities caught the attention of several investigators which study the relationships between plants and soil and the potential application of selected bacterial species in crop improvement and protection. Medicago sativa L. is a legume crop of high economic importance as forage in temperate areas and one of the most popular model plants for investigations on the symbiosis with nitrogen fixing rhizobia (mainly belonging to the alphaproteobacterial species Sinorhizobium meliloti). However, despite its importance, no studies have been carried out looking at the total bacterial community associated with the plant. In this work we explored for the first time the total bacterial community associated with M. sativa plants grown in mesocosms conditions, looking at a wide taxonomic spectrum, from the class to the single species (S. meliloti) level. Results Results, obtained by using Terminal-Restriction Fragment Length Polymorphism (T-RFLP) analysis, quantitative PCR and sequencing of 16 S rRNA gene libraries, showed a high taxonomic diversity as well as a dominance by members of the class Alphaproteobacteria in plant tissues. Within Alphaproteobacteria the families Sphingomonadaceae and Methylobacteriaceae were abundant inside plant tissues, while soil Alphaproteobacteria were represented by the families of Hyphomicrobiaceae, Methylocystaceae, Bradyirhizobiaceae and Caulobacteraceae. At the single species level, we were able to detect the presence of S. meliloti populations in aerial tissues, nodules and soil. An analysis of population diversity on nodules and soil showed a relatively low sharing of haplotypes (30-40%) between the two environments and between replicate mesocosms, suggesting drift as main force shaping S. meliloti population at least in this system. Conclusions In this work we shed some light on the bacterial communities associated with M. sativa plants, showing that Alphaproteobacteria may constitute an important

  6. Ethical Leadership and Moral Literacy: Incorporating Ethical Dilemmas in a Case-­Based Pedagogy

    ERIC Educational Resources Information Center

    Jenlink, Patrick M.; Jenlink, Karen Embry

    2015-01-01

    In this paper the authors examine an ethical dilemma approach to case-based pedagogy for leadership preparation, which was used in a doctoral studies program. Specifically, the authors argue that preparing educational leaders for the ethical dilemmas and moral decision-making that define schools requires assessing current programs and pedagogical…

  7. New Stories of Mastery: Constructive Learning in the Face of Complex Dilemmas of Practice

    ERIC Educational Resources Information Center

    Cherry, Nita L.

    2014-01-01

    This paper suggests that complex practice dilemmas call for thick stories of masterful practice that don't ignore the tensions and ambiguities involved. The paper draws on an Australian study of policing as a fruitful example. Academic commentary suggests policing is beset with practice dilemmas unique in their complexity. However, empirical…

  8. Contrasting Ecological Processes and Functional Compositions Between Intestinal Bacterial Community in Healthy and Diseased Shrimp.

    PubMed

    Zhu, Jinyong; Dai, Wenfang; Qiu, Qiongfen; Dong, Chunming; Zhang, Jinjie; Xiong, Jinbo

    2016-11-01

    Intestinal bacterial communities play a pivotal role in promoting host health; therefore, the disruption of intestinal bacterial homeostasis could result in disease. However, the effect of the occurrences of disease on intestinal bacterial community assembly remains unclear. To address this gap, we compared the multifaceted ecological differences in maintaining intestinal bacterial community assembly between healthy and diseased shrimps. The neutral model analysis shows that the relative importance of neutral processes decreases when disease occurs. This pattern is further corroborated by the ecosphere null model, revealing that the bacterial community assembly of diseased samples is dominated by stochastic processes. In addition, the occurrence of shrimp disease reduces the complexity and cooperative activities of species-to-species interactions. The keystone taxa affiliated with Alphaproteobacteria and Actinobacteria in healthy shrimp gut shift to Gammaproteobacteria species in diseased shrimp. Changes in intestinal bacterial communities significantly alter biological functions in shrimp. Within a given metabolic pathway, the pattern of enrichment or decrease between healthy and deceased shrimp is correlated with its functional effects. We propose that stressed shrimp are more prone to invasion by alien strains (evidenced by more stochastic assembly and higher migration rate in diseased shrimp), which, in turn, disrupts the cooperative activity among resident species. These findings greatly aid our understanding of the underlying mechanisms that govern shrimp intestinal community assembly between health statuses.

  9. Tensions and Dilemmas in Leading Australia's Schools

    ERIC Educational Resources Information Center

    Gurr, David; Drysdale, Lawrie

    2012-01-01

    In this article we address several tensions and dilemmas that are impacting on Australian principals and other school leaders. The first section explores areas associated with improving teaching and learning and includes discussion of education trends, the construction of new learning environments and the implication of these for more…

  10. [When to consult the institutional bioethics committee? The deliberative method for resolving possible dilemmas].

    PubMed

    Rabadán, Alejandra T; Tripodoro, Vilma A

    2017-01-01

    In healthcare, an ethical concern that arises during the decision making process is considered to be a bioethical dilemma. It is often the case that in the absence of proper deliberation, the problem is transferred to a bioethics committee, not even representing precisely a dilemma. Bioethics emerged as a discipline in the mid-20th century. It is defined as a support to decision-making in ethical dilemmas centered on two aspects: ethics of clinical investigation, focused on protecting the rights of research subjects, and bioethics in medical practice, of an advisory nature. To recognize the difference among difficult or complex clinical circumstances and ethical dilemmas could allow knowing when it is necessary to request for advice of a committee. It is not so much a question of deciding what is right or wrong, but which is the most advisable solution to a problem. We review the history of Bioethics Committees in Argentina that are facing today the challenge of promoting social responsibility and opening deliberations to community and health professionals. In the 20th century two historical moments are recognized: a pioneering and slow first period, and a second one of legal regulatory framework. Considering deliberation as a method of ethics, this article proposes a case analysis procedure and the deliberative method to elucidate dilemmas, with or without the help of a Committee.

  11. Biodegradation of free cyanide by bacterial species isolated from cyanide-contaminated artisanal gold mining catchment area in Burkina Faso.

    PubMed

    Razanamahandry, Lovasoa Christine; Andrianisa, Harinaivo Anderson; Karoui, Hela; Kouakou, Koffi Marcelin; Yacouba, Hamma

    2016-08-01

    Soil and water samples were collected from a watershed in Burkina Faso where illegal artisanal gold extraction using cyanidation occurs. The samples were used to evaluate cyanide contamination and the presence of cyanide degrading bacteria (CDB). Free cyanide (F-CN) was detected in all samples, with concentrations varying from 0.023 to 0.9 mg kg(-1), and 0.7-23 μg L(-1) in the soil and water samples, respectively. Potential CDB also were present in the samples. To test the effective F-CN degradation capacity of the isolated CDB species, the species were cultivated in growth media containing 40, 60 or 80 mg F-CN L(-1), with or without nutrients, at pH 9.5 and at room temperature. More than 95% of F-CN was degraded within 25 h, and F-CN degradation was associated with bacterial growth and ammonium production. However, initial concentrations of F-CN higher than 100 mg L(-1) inhibited bacterial growth and cyanide degradation. Abiotic tests showed that less than 3% of F-CN was removed by volatilization. Thus, the degradation of F-CN occurred predominately by biological mechanisms, and such mechanisms are recommended for remediation of contaminated soil and water. The bacteria consortium used in the experiment described above exist in a Sahelian climate, which is characterized by a long hot and dry season. Because the bacteria are already adapted to the local climate conditions and show the potential for cyanide biodegradation, further applicability to other contaminated areas in West Africa, where illegal gold cyanidation is widespread, should be explored. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Feasibility of physical map construction from fingerprinted bacterial artificial chromosome libraries of polyploid plant species

    PubMed Central

    2010-01-01

    Background The presence of closely related genomes in polyploid species makes the assembly of total genomic sequence from shotgun sequence reads produced by the current sequencing platforms exceedingly difficult, if not impossible. Genomes of polyploid species could be sequenced following the ordered-clone sequencing approach employing contigs of bacterial artificial chromosome (BAC) clones and BAC-based physical maps. Although BAC contigs can currently be constructed for virtually any diploid organism with the SNaPshot high-information-content-fingerprinting (HICF) technology, it is currently unknown if this is also true for polyploid species. It is possible that BAC clones from orthologous regions of homoeologous chromosomes would share numerous restriction fragments and be therefore included into common contigs. Because of this and other concerns, physical mapping utilizing the SNaPshot HICF of BAC libraries of polyploid species has not been pursued and the possibility of doing so has not been assessed. The sole exception has been in common wheat, an allohexaploid in which it is possible to construct single-chromosome or single-chromosome-arm BAC libraries from DNA of flow-sorted chromosomes and bypass the obstacles created by polyploidy. Results The potential of the SNaPshot HICF technology for physical mapping of polyploid plants utilizing global BAC libraries was evaluated by assembling contigs of fingerprinted clones in an in silico merged BAC library composed of single-chromosome libraries of two wheat homoeologous chromosome arms, 3AS and 3DS, and complete chromosome 3B. Because the chromosome arm origin of each clone was known, it was possible to estimate the fidelity of contig assembly. On average 97.78% or more clones, depending on the library, were from a single chromosome arm. A large portion of the remaining clones was shown to be library contamination from other chromosomes, a feature that is unavoidable during the construction of single

  13. Professionalism dilemmas, moral distress and the healthcare student: insights from two online UK-wide questionnaire studies.

    PubMed

    Monrouxe, Lynn V; Rees, Charlotte E; Dennis, Ian; Wells, Stephanie E

    2015-05-19

    To understand the prevalence of healthcare students' witnessing or participating in something that they think unethical (professionalism dilemmas) during workplace learning and examine whether differences exist in moral distress intensity resulting from these experiences according to gender and the frequency of occurrence. Two cross-sectional online questionnaires of UK medical (study 1) and nursing, dentistry, physiotherapy and pharmacy students (study 2) concerning professionalism dilemmas and subsequent distress for (1) Patient dignity and safety breaches; (2) Valid consent for students' learning on patients; and (3) Negative workplace behaviours (eg, student abuse). 2397 medical (67.4% female) and 1399 other healthcare students (81.1% female) responded. The most commonly encountered professionalism dilemmas were: student abuse and patient dignity and safety dilemmas. Multinomial and logistic regression identified significant effects for gender and frequency of occurrence. In both studies, men were more likely to classify themselves as experiencing no distress; women were more likely to classify themselves as distressed. Two distinct patterns concerning frequency were apparent: (1) Habituation (study 1): less distress with increased exposure to dilemmas 'justified' for learning; (2) Disturbance (studies 1 and 2): more distress with increased exposure to dilemmas that could not be justified. Tomorrow's healthcare practitioners learn within a workplace in which they frequently encounter dilemmas resulting in distress. Gender differences could be respondents acting according to gendered expectations (eg, males downplaying distress because they are expected to appear tough). Habituation to dilemmas suggests students might balance patient autonomy and right to dignity with their own needs to learn for future patient benefit. Disturbance contests the 'accepted' notion that students become less empathic over time. Future research might examine the strategies that

  14. Gut bacterial communities across tadpole ecomorphs in two diverse tropical anuran faunas

    NASA Astrophysics Data System (ADS)

    Vences, Miguel; Lyra, Mariana L.; Kueneman, Jordan G.; Bletz, Molly C.; Archer, Holly M.; Canitz, Julia; Handreck, Svenja; Randrianiaina, Roger-Daniel; Struck, Ulrich; Bhuju, Sabin; Jarek, Michael; Geffers, Robert; McKenzie, Valerie J.; Tebbe, Christoph C.; Haddad, Célio F. B.; Glos, Julian

    2016-04-01

    Animal-associated microbial communities can play major roles in the physiology, development, ecology, and evolution of their hosts, but the study of their diversity has yet focused on a limited number of host species. In this study, we used high-throughput sequencing of partial sequences of the bacterial 16S rRNA gene to assess the diversity of the gut-inhabiting bacterial communities of 212 specimens of tropical anuran amphibians from Brazil and Madagascar. The core gut-associated bacterial communities among tadpoles from two different continents strongly overlapped, with eight highly represented operational taxonomic units (OTUs) in common. In contrast, the core communities of adults and tadpoles from Brazil were less similar with only one shared OTU. This suggests a community turnover at metamorphosis. Bacterial diversity was higher in tadpoles compared to adults. Distinct differences in composition and diversity occurred among gut bacterial communities of conspecific tadpoles from different water bodies and after experimental fasting for 8 days, demonstrating the influence of both environmental factors and food on the community structure. Communities from syntopic tadpoles clustered by host species both in Madagascar and Brazil, and the Malagasy tadpoles also had species-specific isotope signatures. We recommend future studies to analyze the turnover of anuran gut bacterial communities at metamorphosis, compare the tadpole core communities with those of other aquatic organisms, and assess the possible function of the gut microbiota as a reservoir for protective bacteria on the amphibian skin.

  15. Memory boosts turn taking in evolutionary dilemma games.

    PubMed

    Wang, Tao; Chen, Zhigang; Yang, Lei; Zou, You; Luo, Juan

    2015-05-01

    Spontaneous turn taking phenomenon can be observed in many self-organized systems, and the mechanism is unclear. This paper tries to model it by evolutionary dilemma games with memory mechanism. Prisoner's dilemma, Snowdrift (including Leader and Hero) and Stag-hunt games are unified on an extended S-T plane. Agents play game with all the others and make decision by the last game histories. The experiments find that when agents remember last 2-step histories or more, a kind of cooperative turn taking (CAD) bursts at the area of Snowdrift game with restriction of S + T > 2R and S ≠ T, while the consistent strategy (DorC) gathers on the line of S + T > 2R and S = T. We also find that the system's fitness ratio greatly improved with 2-step memory. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  16. Cognition and norms: toward a developmental account of moral agency in social dilemmas

    PubMed Central

    Meyer, Leandro F. F.; Braga, Marcelo J.

    2015-01-01

    Most recent developments in the study of social dilemmas give an increasing amount of attention to cognition, belief systems, valuations, and language. However, developments in this field operate almost entirely under epistemological assumptions which only recognize the instrumental form of rationality and deny that “value judgments” or “moral questions” have cognitive content. This standpoint erodes the moral aspect of the choice situation and obstructs acknowledgment of the links connecting cognition, inner growth, and moral reasoning, and the significance of such links in reaching cooperative solutions to many social dilemmas. Concurrently, this standpoint places the role of communication and mutual understanding in promoting cooperation in morally relevant conflicts of action in a rather mysterious situation. This paper draws on Habermas’s critique of instrumental action, and on the most recent developments in institutional and behavioral economics with a view to enhancing our knowledge of the interventions used to cope with social dilemmas. We conclude the paper with a brief presentation of a research strategy for examining the capacity of alternative developmental models to predict dissimilar choices under similar incentive conditions in social dilemmas. PMID:25610414

  17. Diversity of Hindgut Bacterial Population in Subterranean Termite, Reticulitermes flavipes

    Treesearch

    Olanrewaju Raji; Dragica Jeremic-Nikolic; Juliet D. Tang

    2017-01-01

    The termite hindgut contains a bacterial community that symbiotically aids in digestion of cellulosic materials. For this paper, a species survey of bacterial hindgut symbionts in termites collected from Saucier, Mississippi was examined. Two methods were tested for optimal genetic material isolation. Genomic DNA was isolated from the hindgut luminal contents of five...

  18. Identification of causative pathogens in mouse eyes with bacterial keratitis by sequence analysis of 16S rDNA libraries

    PubMed Central

    Song, Hong-Yan; Qiu, Bao-Feng; Liu, Chun; Zhu, Shun-Xing; Wang, Sheng-Cun; Miao, Jin; Jing, Jing; Shao, Yi-Xiang

    2014-01-01

    The clone library method using PCR amplification of the 16S ribosomal RNA (rRNA) gene was used to identify pathogens from corneal scrapings of C57BL/6-corneal opacity (B6-Co) mice with bacterial keratitis. All 10 samples from the eyes with bacterial keratitis showed positive PCR results. All 10 samples from the normal cornea showed negative PCR results. In all 10 PCR-positive samples, the predominant and second most predominant species accounted for 20.9 to 40.6% and 14.7 to 26.1%, respectively, of each clone library. The predominant species were Staphylococcus lentus, Pseudomonas aeruginosa, and Staphylococcus epidermidis. The microbiota analysis detected a diverse group of microbiota in the eyes of B6-Co mice with bacterial keratitis and showed that the causative pathogens could be determined based on percentages of bacterial species in the clone libraries. The bacterial species detected in this study were mostly in accordance with results of studies on clinical bacterial keratitis in human eyes. Based on the results of our previous studies and this study, the B6-Co mouse should be considered a favorable model for studying bacterial keratitis. PMID:25312507

  19. Elucidating Duramycin’s Bacterial Selectivity and Mode of Action on the Bacterial Cell Envelope

    DOE PAGES

    Hasim, Sahar; Allison, David P.; Mendez, Berlin; ...

    2018-02-14

    The use of naturally occurring antimicrobial peptides provides a promising route to selectively target pathogenic agents and to shape microbiome structure. Lantibiotics, such as duramycin, are one class of bacterially produced peptidic natural products that can selectively inhibit the growth of other bacteria. However, despite longstanding characterization efforts, the microbial selectivity and mode of action of duramycin are still obscure. We describe here a suite of biological, chemical, and physical characterizations that shed new light on the selective and mechanistic aspects of duramycin activity. Bacterial screening assays have been performed using duramycin and Populus-derived bacterial isolates to determine species selectivity.more » Lipidomic profiles of selected resistant and sensitive strains show that the sensitivity of Gram-positive bacteria depends on the presence of phosphatidylethanolamine (PE) in the cell membrane. Further the surface and interface morphology were studied by high resolution atomic force microscopy and showed a progression of cellular changes in the cell envelope after treatment with duramycin for the susceptible bacterial strains. Together, these molecular and cellular level analyses provide insight into duramycin’s mode of action and a better understanding of its selectivity.« less

  20. Elucidating Duramycin’s Bacterial Selectivity and Mode of Action on the Bacterial Cell Envelope

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hasim, Sahar; Allison, David P.; Mendez, Berlin

    The use of naturally occurring antimicrobial peptides provides a promising route to selectively target pathogenic agents and to shape microbiome structure. Lantibiotics, such as duramycin, are one class of bacterially produced peptidic natural products that can selectively inhibit the growth of other bacteria. However, despite longstanding characterization efforts, the microbial selectivity and mode of action of duramycin are still obscure. We describe here a suite of biological, chemical, and physical characterizations that shed new light on the selective and mechanistic aspects of duramycin activity. Bacterial screening assays have been performed using duramycin and Populus-derived bacterial isolates to determine species selectivity.more » Lipidomic profiles of selected resistant and sensitive strains show that the sensitivity of Gram-positive bacteria depends on the presence of phosphatidylethanolamine (PE) in the cell membrane. Further the surface and interface morphology were studied by high resolution atomic force microscopy and showed a progression of cellular changes in the cell envelope after treatment with duramycin for the susceptible bacterial strains. Together, these molecular and cellular level analyses provide insight into duramycin’s mode of action and a better understanding of its selectivity.« less

  1. Ethical Dilemmas in Retail Merchandising: Student Perceptions

    ERIC Educational Resources Information Center

    Paulins, V. Ann; Lombardy, Lisa

    2005-01-01

    Ethical dilemmas observed by students in retailing internships were the basis for a survey in which students indicated their perceptions as to whether case situations involved unethical behavior. Expanded case situations were offered to students for further exploration. The specific questions posed in this study included the following: (1) In what…

  2. Teachers' Ethical Dilemmas: What Would You Do?

    ERIC Educational Resources Information Center

    Bucholz, Jessica L.; Keller, Cassandra L.; Brady, Michael P.

    2007-01-01

    Educators will face a variety of ethical and moral dilemmas throughout their teaching careers; however, they do not have a common board that governs its members' ethical behavior. Instead, there are numerous educational organizations that have written their own specific codes for ethical behavior. The Council for Exceptional Children (CEC) has…

  3. Collective influence in evolutionary social dilemmas

    NASA Astrophysics Data System (ADS)

    Szolnoki, Attila; Perc, Matjaž

    2016-03-01

    When evolutionary games are contested in structured populations, the degree of each player in the network plays an important role. If they exist, hubs often determine the fate of the population in remarkable ways. Recent research based on optimal percolation in random networks has shown, however, that the degree is neither the sole nor the best predictor of influence in complex networks. Low-degree nodes may also be optimal influencers if they are hierarchically linked to hubs. Taking this into account leads to the formalism of collective influence in complex networks, which as we show here, has far-reaching implications for the favorable resolution of social dilemmas. In particular, there exists an optimal hierarchical depth for the determination of collective influence that we use to describe the potency of players for passing their strategies, which depends on the strength of the social dilemma. Interestingly, the degree, which corresponds to the baseline depth zero, is optimal only when the temptation to defect is small. Our research reveals that evolutionary success stories are related to spreading processes which are rooted in favorable hierarchical structures that extend beyond local neighborhoods.

  4. Incidental emotions in moral dilemmas: the influence of emotion regulation.

    PubMed

    Szekely, Raluca D; Miu, Andrei C

    2015-01-01

    Recent theories have argued that emotions play a central role in moral decision-making and suggested that emotion regulation may be crucial in reducing emotion-linked biases. The present studies focused on the influence of emotional experience and individual differences in emotion regulation on moral choice in dilemmas that pit harming another person against social welfare. During these "harm to save" moral dilemmas, participants experienced mostly fear and sadness but also other emotions such as compassion, guilt, anger, disgust, regret and contempt (Study 1). Fear and disgust were more frequently reported when participants made deontological choices, whereas regret was more frequently reported when participants made utilitarian choices. In addition, habitual reappraisal negatively predicted deontological choices, and this effect was significantly carried through emotional arousal (Study 2). Individual differences in the habitual use of other emotion regulation strategies (i.e., acceptance, rumination and catastrophising) did not influence moral choice. The results of the present studies indicate that negative emotions are commonly experienced during "harm to save" moral dilemmas, and they are associated with a deontological bias. By efficiently reducing emotional arousal, reappraisal can attenuate the emotion-linked deontological bias in moral choice.

  5. Ethical dilemmas facing chief nurses in Japan: A Pilot study.

    PubMed

    Ito, Chiharu; Natsume, Mikiko

    2016-06-01

    Chief nurses are most likely to take the lead in discussing and working to resolve ethical dilemmas, creating an ethical culture within their organization that results in effective ethics training. As the first step in this process, there is a need to define the kinds of ethical dilemmas that chief nurses grapple with on a regular basis as a target for future study. Anonymous written questionnaires and semi-structured interviews. All research procedures were approved by the Chubu University Ethics Review Board, the research institution to which the authors belong (authorization no. 250016). Responses from four chief nurses indicated that ethical dilemmas could be categorized as either those related to patient dignity or those related to management (unique to their roles as administrators). It was also learned that chief nurses struggle with the fact that although they consult with their superiors and others, these efforts do not lead to resolution. The expectation is that going forward, chief nurses will play a central role in acting as coordinators with physicians to promote better communication as well as lead group discussions aimed at providing care that respects patient dignity. © The Author(s) 2015.

  6. Bacterial flora in abnormalities of the female genital tract

    PubMed Central

    Gordon, A. M.; Hughes, H. E.; Barr, G. T. D.

    1966-01-01

    The bacterial flora associated with certain common abnormalities of the female genital tract were studied. The abnormalities included were trichomonal infestation of the vagina, the epithelial inflammation and cellular atypia associated with protozoal infestation, and erosions of the cervix. Trichomonas vaginalis infestation and marked epithelial inflammation were associated with a very varied bacterial flora in which Mycoplasma species, streptococci, and `Haemophilus vaginalis' (Gardner and Dukes, 1955) were often prominent. No cases of vaginitis attributable to Haemophilus vaginalis were detected. An essentially normal bacterial flora accompanied erosions of the cervix. PMID:5919354

  7. Teaching Literature and Literacy in the Eye of Reform: A Dilemma in Three Acts.

    ERIC Educational Resources Information Center

    Florio-Ruane, Susan; Berne, Jennifer; Raphael, Taffy E.

    2001-01-01

    Tells a story of crossing borders in support of dilemma management in the teaching of literature. Discusses working together to manage dilemmas in literacy and teacher education. Sketches the genealogy of a network of teachers from across the southeast region of Michigan. Focuses on the teachers working in the "eye of reform" at an…

  8. School Leaders' Dilemmas and Measures to Instigate Changes for Inclusive Education in Hong Kong

    ERIC Educational Resources Information Center

    Poon-McBrayer, Kim Fong

    2017-01-01

    The roles of principal leadership in change management have long been documented. The key concern to examine in this study was the dilemmas and measures confronting principals' when they led changes to instigate inclusive education in Hong Kong. Thus, this paper aims to report sources of dilemmas and how principals tackled them in the change…

  9. Bacterial Community Composition Associated with Chironomid Egg Masses

    PubMed Central

    Senderovich, Yigal; Halpern, Malka

    2012-01-01

    Chironomids (Diptera: Chironomidae) are the most widely distributed and often the most abundant insect in freshwater. They undergo a complete metamorphosis of four life stages, of which the egg, larva, and pupae are aquatic and the adult is terrestrial. Chironomid egg masses were found to be natural reservoirs of Vibrio cholerae and Aeromonas species. To expand the knowledge of the endogenous bacterial community associated with chironomid egg masses, denaturing gradient gel electrophoresis and clone analysis of 16S rRNA gene libraries were used in this study. Bacterial community composition associated with chironomid egg masses was found to be stable among different sampling periods. Cloned libraries of egg masses revealed that about 40% of the clones were related to bacteria known to degrade various toxicants. These findings were further supported when bacterial species that showed resistance to different toxic metals were isolated from egg masses and larval samples. Chironomids are found under a wide range of water conditions and are able to survive pollutants. However, little is known about their protective mechanisms under these conditions. Chironomid egg masses are inhabited by a stable endogenous bacterial community, which may potentially play a role in protecting chironomids from toxicants in polluted environments. Further study is needed to support this hypothesis. PMID:23461272

  10. Dynamic social networks facilitate cooperation in the N-player Prisoner’s Dilemma

    NASA Astrophysics Data System (ADS)

    Rezaei, Golriz; Kirley, Michael

    2012-12-01

    Understanding how cooperative behaviour evolves in network communities, where the individual members interact via social dilemma games, is an on-going challenge. In this paper, we introduce a social network based model to investigate the evolution of cooperation in the N-player Prisoner’s Dilemma game. As such, this work complements previous studies focused on multi-player social dilemma games and endogenous networks. Agents in our model, employ different game-playing strategies reflecting varying cognitive capacities. When an agent plays cooperatively, a social link is formed with each of the other N-1 group members. Subsequent cooperative actions reinforce this link. However, when an agent defects, the links in the social network are broken. Computational simulations across a range of parameter settings are used to examine different scenarios: varying population and group sizes; the group formation process (or partner selection); and agent decision-making strategies under varying dilemma constraints (cost-to-benefit ratios), including a “discriminator” strategy where the action is based on a function of the weighted links within an agent’s social network. The simulation results show that the proposed social network model is able to evolve and maintain cooperation. As expected, as the value of N increases the equilibrium proportion of cooperators in the population decreases. In addition, this outcome is dependent on the dilemma constraint (cost-to-benefit ratio). However, in some circumstances the dynamic social network plays an increasingly important role in promoting and sustaining cooperation, especially when the agents adopt the discriminator strategy. The adjustment of social links results in the formation of communities of “like-minded” agents. Subsequently, this local optimal behaviour promotes the evolution of cooperative behaviour at the system level.

  11. Bacterial biofilm composition in caries and caries-free subjects.

    PubMed

    Wolff, D; Frese, C; Maier-Kraus, T; Krueger, T; Wolff, B

    2013-01-01

    Certain major pathogens such as Streptococcus mutans, Lactobacillus spp. and others have been reported to be involved in caries initiation and progression. Yet, in addition to those leading pathogens, microbial communities seem to be much more diverse and individually differing. The aim of this study, therefore, was to analyze the bacterial composition of carious dentin and the plaque of caries-free patients by using a custom-made, real-time quantitative polymerase chain reaction assay (RQ-PCR). The study included 26 patients with caries and 28 caries-free controls. Decayed tooth substance and plaque samples were harvested. Bacterial DNA was extracted and tested for the presence of 43 bacterial species or species groups using RQ-PCR. Relative quantification revealed that Propionibacterium acidifaciens was significantly more abundant in caries samples than were other microorganisms (fold change 169.12, p = 0.023). In the caries-free samples, typical health-associated species were significantly more prevalent. Unsupervised hierarchical cluster analysis showed a high abundance of P. acidifaciens in caries subjects and distinct but individually differing bacterial clusters in the caries-free subjects. The distribution of 11 bacteria allowed full discrimination between caries and caries-free subjects. Within the investigated cohort, P. acidifaciens was the only pathogen significantly more abundant in caries subjects. Cluster analysis yielded a diverse flora in caries-free subjects, whereas it was narrowed down to a small range of a few outcompeting members in caries subjects. Copyright © 2012 S. Karger AG, Basel.

  12. Does Moral Case Deliberation Help Professionals in Care for the Homeless in Dealing with Their Dilemmas? A Mixed-Methods Responsive Study.

    PubMed

    Spijkerboer, R P; van der Stel, J C; Widdershoven, G A M; Molewijk, A C

    2017-03-01

    Health care professionals often face moral dilemmas. Not dealing constructively with moral dilemmas can cause moral distress and can negatively affect the quality of care. Little research has been documented with methodologies meant to support professionals in care for the homeless in dealing with their dilemmas. Moral case deliberation (MCD) is a method for systematic reflection on moral dilemmas and is increasingly being used as ethics support for professionals in various health-care domains. This study deals with the question: What is the contribution of MCD in helping professionals in an institution for care for the homeless to deal with their moral dilemmas? A mixed-methods responsive evaluation design was used to answer the research question. Five teams of professionals from a Dutch care institution for the homeless participated in MCD three times. Professionals in care for the homeless value MCD positively. They report that MCD helped them to identify the moral dilemma/question, and that they learned from other people's perspectives while reflecting and deliberating on the values at stake in the dilemma or moral question. They became aware of the moral dimension of moral dilemmas, of related norms and values, of other perspectives, and learned to formulate a moral standpoint. Some experienced the influence of MCD in the way they dealt with moral dilemmas in daily practice. Half of the professionals expect MCD will influence the way they deal with moral dilemmas in the future. Most of them were in favour of further implementation of MCD in their organization.

  13. Bacterial gene transfer by natural genetic transformation in the environment.

    PubMed Central

    Lorenz, M G; Wackernagel, W

    1994-01-01

    Natural genetic transformation is the active uptake of free DNA by bacterial cells and the heritable incorporation of its genetic information. Since the famous discovery of transformation in Streptococcus pneumoniae by Griffith in 1928 and the demonstration of DNA as the transforming principle by Avery and coworkers in 1944, cellular processes involved in transformation have been studied extensively by in vitro experimentation with a few transformable species. Only more recently has it been considered that transformation may be a powerful mechanism of horizontal gene transfer in natural bacterial populations. In this review the current understanding of the biology of transformation is summarized to provide the platform on which aspects of bacterial transformation in water, soil, and sediments and the habitat of pathogens are discussed. Direct and indirect evidence for gene transfer routes by transformation within species and between different species will be presented, along with data suggesting that plasmids as well as chromosomal DNA are subject to genetic exchange via transformation. Experiments exploring the prerequisites for transformation in the environment, including the production and persistence of free DNA and factors important for the uptake of DNA by cells, will be compiled, as well as possible natural barriers to transformation. The efficiency of gene transfer by transformation in bacterial habitats is possibly genetically adjusted to submaximal levels. The fact that natural transformation has been detected among bacteria from all trophic and taxonomic groups including archaebacteria suggests that transformability evolved early in phylogeny. Probable functions of DNA uptake other than gene acquisition will be discussed. The body of information presently available suggests that transformation has a great impact on bacterial population dynamics as well as on bacterial evolution and speciation. PMID:7968924

  14. Bacterial population dynamics in recycled mushroom compost leachate.

    PubMed

    Safianowicz, Katarzyna; Bell, Tina L; Kertesz, Michael A

    2018-06-01

    Mushrooms are an important food crop throughout the world. The most important edible mushroom is the button mushroom (Agaricus bisporus), which comprises about 30% of the global mushroom market. This species is cultivated commercially on a selective compost that is produced predominantly from wheat straw/stable bedding and chicken manure, at a moisture content of around 70% (w/w) and temperatures of up to 80 °C. Large volumes of water are required to achieve this moisture content, and many producers therefore collect leachate from the composting windrows and bunkers (known in the industry as "goody water") and reuse it to wet the raw ingredients. This has the benefit of recycling and saving water and has the potential to enrich beneficial microorganisms that stimulate composting, but also the risk of enhancing pathogen populations that could reduce productivity. Here, we show by 16S rRNA gene sequencing that mushroom compost leachate contains a high diversity of unknown microbes, with most of the species found affiliated with the phyla Firmicutes and Proteobacteria. However, by far the most abundant species was the thermophile Thermus thermophilus, which made up approximately 50% of the bacterial population present. Although the leachate was routinely collected and stored in an aerated central storage tank, many of the bacterial species found in leachate were facultative anaerobes. However, there was no evidence for sulfide production, and no sulfate-reducing bacterial species were detected. Because T. thermophilus is important in the high temperature phase of composting, the use of recycled leachate as an inoculum for the raw materials is likely to be beneficial for the composting process.

  15. Bacterial communities in ancient permafrost profiles of Svalbard, Arctic.

    PubMed

    Singh, Purnima; Singh, Shiv M; Singh, Ram N; Naik, Simantini; Roy, Utpal; Srivastava, Alok; Bölter, Manfred

    2017-12-01

    Permafrost soils are unique habitats in polar environment and are of great ecological relevance. The present study focuses on the characterization of bacterial communities from permafrost profiles of Svalbard, Arctic. Counts of culturable bacteria range from 1.50 × 10 3 to 2.22 × 10 5 CFU g -1 , total bacterial numbers range from 1.14 × 10 5 to 5.52 × 10 5 cells g -1 soil. Bacterial isolates are identified through 16S rRNA gene sequencing. Arthrobacter and Pseudomonas are the most dominant genera, and A. sulfonivorans, A. bergeri, P. mandelii, and P. jessenii as the dominant species. Other species belong to genera Acinetobacter, Bacillus, Enterobacter, Nesterenkonia, Psychrobacter, Rhizobium, Rhodococcus, Sphingobacterium, Sphingopyxis, Stenotrophomonas, and Virgibacillus. To the best of our knowledge, genera Acinetobacter, Enterobacter, Nesterenkonia, Psychrobacter, Rhizobium, Sphingobacterium, Sphingopyxis, Stenotrophomonas, and Virgibacillus are the first northernmost records from Arctic permafrost. The present study fills the knowledge gap of culturable bacterial communities and their chronological characterization from permafrost soils of Ny-Ålesund (79°N), Arctic. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Interactions of Seedborne Bacterial Pathogens with Host and Non-Host Plants in Relation to Seed Infestation and Seedling Transmission

    PubMed Central

    Dutta, Bhabesh; Gitaitis, Ronald; Smith, Samuel; Langston, David

    2014-01-01

    The ability of seed-borne bacterial pathogens (Acidovorax citrulli, Clavibacter michiganensis subsp. michiganensis, Pseudomonas syringae pv. tomato, Xanthomonas euvesicatoria, and Pseudomonas syringae pv. glycinea) to infest seeds of host and non-host plants (watermelon, tomato, pepper, and soybean) and subsequent pathogen transmission to seedlings was investigated. A non-pathogenic, pigmented strain of Serratia marcescens was also included to assess a null-interacting situation with the same plant species. Flowers of host and non-host plants were inoculated with 1×106 colony forming units (CFUs)/flower for each bacterial species and allowed to develop into fruits or umbels (in case of onion). Seeds harvested from each host/non-host bacterial species combination were assayed for respective bacteria by plating on semi-selective media. Additionally, seedlots for each host/non-host bacterial species combination were also assayed for pathogen transmission by seedling grow-out (SGO) assays under greenhouse conditions. The mean percentage of seedlots infested with compatible and incompatible pathogens was 31.7 and 30.9% (by plating), respectively and they were not significantly different (P = 0.67). The percentage of seedlots infested with null-interacting bacterial species was 16.8% (by plating) and it was significantly lower than the infested lots generated with compatible and incompatible bacterial pathogens (P = 0.03). None of the seedlots with incompatible/null-interacting bacteria developed symptoms on seedlings; however, when seedlings were assayed for epiphytic bacterial presence, 19.5 and 9.4% of the lots were positive, respectively. These results indicate that the seeds of non-host plants can become infested with incompatible and null-interacting bacterial species through flower colonization and they can be transmitted via epiphytic colonization of seedlings. In addition, it was also observed that flowers and seeds of non-host plants can be colonized

  17. Characterization of the Cultivable Gut Microflora in Wild-Caught 
Mediterranean Fish Species.

    PubMed

    Jammal, Ahmad; Bariche, Michel; Zu Dohna, Heinrich; Kambris, Zakaria

    2017-05-01

    Microflora of the gastrointestinal tract plays important roles in food digestion, nutrient absorption and in host defense against ingested pathogens. Several studies have focused on the microflora of farmed fishes, but the gut flora of wild fishes remains poorly characterized. The aim of this work was to provide an overview of the bacteria colonizing the gut of wild-caught fishes and to determine whether some bacterial species can be pathogenic. We isolated cultivable bacteria from fifteen wild-caught Mediterranean fish species corresponding to different habitat, diet and origin. Bacterial species identity was determined by 16s rRNA gene sequencing for the 61 isolates. The potential pathogenicity of isolated bacteria was investigated using fruit fly (Drosophila melanogaster) and zebrafish (Danio rerio) as model organisms. Two bacterial strains (Serratia sp. and Aeromonas salmonicida) were lethal when microinjected to Drosophila, while zebrafish did not develop any disease when exposed to any of 34 isolated bacterial strains. However, it was interesting to note that two bacterial strains (Shewanella and Arthrobacter) isolated from marine fishes were able to colonize the guts of freshwater zebrafish. The results of this study give an overview of the bacterial species found in the guts of wild fishes living off Beirut seashore. It shows that some parameters believed to be limiting factors to host-gut colonization by bacteria can be overcome by some species. This pilot study could be extended by sampling a larger number of fish species with several specimens per fish species, and by identifying uncultivable bacteria that reside in the fish guts. Our results may have implications for the utilization of certain bacterial species in fish farming or their use as bio-indicators for water and/or food quality.

  18. Estimating Bacterial Diversity for Ecological Studies: Methods, Metrics, and Assumptions

    PubMed Central

    Birtel, Julia; Walser, Jean-Claude; Pichon, Samuel; Bürgmann, Helmut; Matthews, Blake

    2015-01-01

    Methods to estimate microbial diversity have developed rapidly in an effort to understand the distribution and diversity of microorganisms in natural environments. For bacterial communities, the 16S rRNA gene is the phylogenetic marker gene of choice, but most studies select only a specific region of the 16S rRNA to estimate bacterial diversity. Whereas biases derived from from DNA extraction, primer choice and PCR amplification are well documented, we here address how the choice of variable region can influence a wide range of standard ecological metrics, such as species richness, phylogenetic diversity, β-diversity and rank-abundance distributions. We have used Illumina paired-end sequencing to estimate the bacterial diversity of 20 natural lakes across Switzerland derived from three trimmed variable 16S rRNA regions (V3, V4, V5). Species richness, phylogenetic diversity, community composition, β-diversity, and rank-abundance distributions differed significantly between 16S rRNA regions. Overall, patterns of diversity quantified by the V3 and V5 regions were more similar to one another than those assessed by the V4 region. Similar results were obtained when analyzing the datasets with different sequence similarity thresholds used during sequences clustering and when the same analysis was used on a reference dataset of sequences from the Greengenes database. In addition we also measured species richness from the same lake samples using ARISA Fingerprinting, but did not find a strong relationship between species richness estimated by Illumina and ARISA. We conclude that the selection of 16S rRNA region significantly influences the estimation of bacterial diversity and species distributions and that caution is warranted when comparing data from different variable regions as well as when using different sequencing techniques. PMID:25915756

  19. Social Discounting and the Prisoner's Dilemma Game

    ERIC Educational Resources Information Center

    Locey, Matthew L.; Safin, Vasiliy; Rachlin, Howard

    2013-01-01

    Altruistic behavior has been defined in economic terms as “…costly acts that confer economic benefits on other individuals” (Fehr & Fischbacher, 2003). In a prisoner's dilemma game, cooperation benefits the group but is costly to the individual (relative to defection), yet a significant number of players choose to cooperate. We propose that…

  20. Bacterial profiling of White Plague Disease across corals and oceans indicates a conserved and distinct disease microbiome

    PubMed Central

    Roder, Cornelia; Arif, Chatchanit; Daniels, Camille; Weil, Ernesto; Voolstra, Christian R

    2014-01-01

    Coral diseases are characterized by microbial community shifts in coral mucus and tissue, but causes and consequences of these changes are vaguely understood due to the complexity and dynamics of coral-associated bacteria. We used 16S rRNA gene microarrays to assay differences in bacterial assemblages of healthy and diseased colonies displaying White Plague Disease (WPD) signs from two closely related Caribbean coral species, Orbicella faveolata and Orbicella franksi. Analysis of differentially abundant operational taxonomic units (OTUs) revealed strong differences between healthy and diseased specimens, but not between coral species. A subsequent comparison to data from two Indo-Pacific coral species (Pavona duerdeni and Porites lutea) revealed distinct microbial community patterns associated with ocean basin, coral species and health state. Coral species were clearly separated by site, but also, the relatedness of the underlying bacterial community structures resembled the phylogenetic relationship of the coral hosts. In diseased samples, bacterial richness increased and putatively opportunistic bacteria were consistently more abundant highlighting the role of opportunistic conditions in structuring microbial community patterns during disease. Our comparative analysis shows that it is possible to derive conserved bacterial footprints of diseased coral holobionts that might help in identifying key bacterial species related to the underlying etiopathology. Furthermore, our data demonstrate that similar-appearing disease phenotypes produce microbial community patterns that are consistent over coral species and oceans, irrespective of the putative underlying pathogen. Consequently, profiling coral diseases by microbial community structure over multiple coral species might allow the development of a comparative disease framework that can inform on cause and relatedness of coral diseases. PMID:24350609

  1. Environmental concern and cooperative-competitive behavior in a simulated commons dilemma.

    PubMed

    Smith, J M; Bell, P A

    1992-08-01

    Commons-dilemma simulation games are designed to examine behavior associated with preservation and destruction of slowly regenerating natural resources. In Experiment 1, 120 introductory psychology students in the United States were assigned to high- or low-environmental-concern conditions based on a median split of their scores from a pretest. They then played either a points game, in which they selected numerical points from a slowly regenerating pool, or a tree game, in which they harvested trees from a jointly managed forest. After the game, subjects were asked to sign a petition for an environmental cause, to participate in a litter pick-up, and to participate in a recycling drive. Neither environmental concern nor proenvironmental behaviors were related to commons dilemma performance. In Experiment 2, 57 other introductory psychology students were assessed on environmental concern and Machiavellian personality, size of other players' harvesting choices, and other players' altruistic choices, all correlated with subjects' outcomes in the game. Overall, cooperation and competition were more important than environmental concern in predicting behavior in the commons dilemma simulation game.

  2. Bacterial species and mycotoxin contamination associated with locust bean, melon and their fermented products in south-western Nigeria.

    PubMed

    Adedeji, Bamidele S; Ezeokoli, Obinna T; Ezekiel, Chibundu N; Obadina, Adewale O; Somorin, Yinka M; Sulyok, Michael; Adeleke, Rasheed A; Warth, Benedikt; Nwangburuka, Cyril C; Omemu, Adebukola M; Oyewole, Olusola B; Krska, Rudolf

    2017-10-03

    The microbiological safety of spontaneously fermented foods is not always guaranteed due to the undefined fermenting microbial consortium and processing materials. In this study, two commonly consumed traditional condiments (iru and ogiri) and their respective raw seeds (locust bean and melon) purchased from markets in south-western Nigeria were assessed for bacterial diversity and mycotoxin contamination using 16S rRNA gene sequencing and liquid chromatography tandem mass spectrometry (LC-MS/MS), respectively. Two hundred isolates obtained from the raw seeds and condiments clustered into 10 operational taxonomic units (OTUs) and spanned 3 phyla, 10 genera, 14 species and 2 sub-species. Bacillus (25%) and Staphylococcus (23.5%) dominated other genera. Potentially pathogenic species such as Alcaligenes faecalis, Bacillus anthracis, Proteus mirabilis and Staphylococcus sciuri subsp. sciuri occurred in the samples, suggesting poor hygienic practice during production and/or handling of the condiments. A total of 48 microbial metabolites including 7 mycotoxins [3-nitropropionic acid, aflatoxin B 1 (AFB 1 ), AFB 2 , beauvericin, citrinin, ochratoxin A and sterigmatocystin] were quantified in the food samples. Melon and ogiri had detectable aflatoxin levels whereas locust bean and iru did not; the overall mycotoxin levels in the food samples were low. There is a need to educate processors/vendors of these condiments on good hygienic and processing practices. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Volatiles in Inter-Specific Bacterial Interactions

    PubMed Central

    Tyc, Olaf; Zweers, Hans; de Boer, Wietse; Garbeva, Paolina

    2015-01-01

    The importance of volatile organic compounds for functioning of microbes is receiving increased research attention. However, to date very little is known on how inter-specific bacterial interactions effect volatiles production as most studies have been focused on volatiles produced by monocultures of well-described bacterial genera. In this study we aimed to understand how inter-specific bacterial interactions affect the composition, production and activity of volatiles. Four phylogenetically different bacterial species namely: Chryseobacterium, Dyella, Janthinobacterium, and Tsukamurella were selected. Earlier results had shown that pairwise combinations of these bacteria induced antimicrobial activity in agar media whereas this was not the case for monocultures. In the current study, we examined if these observations were also reflected by the production of antimicrobial volatiles. Thus, the identity and antimicrobial activity of volatiles produced by the bacteria were determined in monoculture as well in pairwise combinations. Antimicrobial activity of the volatiles was assessed against fungal, oomycetal, and bacterial model organisms. Our results revealed that inter-specific bacterial interactions affected volatiles blend composition. Fungi and oomycetes showed high sensitivity to bacterial volatiles whereas the effect of volatiles on bacteria varied between no effects, growth inhibition to growth promotion depending on the volatile blend composition. In total 35 volatile compounds were detected most of which were sulfur-containing compounds. Two commonly produced sulfur-containing volatile compounds (dimethyl disulfide and dimethyl trisulfide) were tested for their effect on three target bacteria. Here, we display the importance of inter-specific interactions on bacterial volatiles production and their antimicrobial activities. PMID:26733959

  4. Theory Ain't Practice: Four Novice Researchers Navigate Dilemmas of Representation within Immigrant Populations

    ERIC Educational Resources Information Center

    Aleixo, Marina; Hansen, Sarah; Horii, Sachiko; Un, Silvy

    2014-01-01

    This article illuminates instances in which four graduate students have struggled with issues of representation--of themselves and of immigrant participants--at their research sites and in their writing. These dilemmas are situated within the literature on the politics of representation in qualitative research. Although these dilemmas are not…

  5. Simultaneous hermaphrodites reproducing in pairs self-fertilize some of their eggs: an experimental test of predictions of mixed-mating and Hermaphrodite's Dilemma theory.

    PubMed

    Lüscher, A; Milinski, M

    2003-09-01

    Theory predicts (1) that mixed-mating systems (i.e. reproduction through both selfing and outcrossing) should usually not evolve and (2) that reproducing simultaneous hermaphrodites should be in a conflict over the preferred sexual role (The Hermaphrodite's Dilemma). In an in vitro system with the endoparasitic cestode Schistocephalus solidus, a simultaneous hermaphrodite, we tested predictions of both the mixed-mating and the Hermaphrodite's Dilemma theory. Using microsatellite markers, we measured the proportion of selfed offspring and the total reproductive output of each worm within pairs varying in mean weight and weight difference. Worms produced more outbred offspring not only with increasing total weight of the pair, but also with decreasing weight difference between the two paired worms. These results suggest: (1) that this parasite species reproduces by mixed-mating, which may be maintained by stochastic density fluctuations in the definitive host and hence unpredictability of self reproduction and (2) reproductive conflict may prevent worm pairs from achieving an optimal intermediate selfing rate.

  6. Pattern Formation of Bacterial Colonies by Escherichia coli

    NASA Astrophysics Data System (ADS)

    Tokita, Rie; Katoh, Takaki; Maeda, Yusuke; Wakita, Jun-ichi; Sano, Masaki; Matsuyama, Tohey; Matsushita, Mitsugu

    2009-07-01

    We have studied the morphological diversity and change in bacterial colonies, using the bacterial species Escherichia coli, as a function of both agar concentration Ca and nutrient concentration Cn. We observed various colony patterns, classified them into four types by pattern characteristics and established a morphological diagram by dividing it into four regions. They are regions A [diffusion-limited aggregation (DLA)-like], B (Eden-like), C (concentric-ring), and D (fluid-spreading). In particular, we have observed a concentric-ring colony growth for E. coli. We focused on the periodic growth in region C and obtained the following results: (i) A colony grows cyclically with the growing front repeating an advance (migration phase) and a momentary rest (consolidation phase) alternately. (ii) The growth width L and the bulge width W in one cycle decrease asymptotically to certain values, when Ca is increased. (iii) L does not depend on Cn, while W is an increasing function of Cn. Plausible mechanisms are proposed to explain the experimental results, by comparing them with those obtained for other bacterial species such as Proteus mirabilis and Bacillus subtilis.

  7. Intra-species bacterial quorum sensing studied at single cell level in a double droplet trapping system.

    PubMed

    Bai, Yunpeng; Patil, Santoshkumar N; Bowden, Steven D; Poulter, Simon; Pan, Jie; Salmond, George P C; Welch, Martin; Huck, Wilhelm T S; Abell, Chris

    2013-05-21

    In this paper, we investigated the intra-species bacterial quorum sensing at the single cell level using a double droplet trapping system. Escherichia coli transformed to express the quorum sensing receptor protein, LasR, were encapsulated in microdroplets that were positioned adjacent to microdroplets containing the autoinducer, N-(3-oxododecanoyl)-L-homoserine lactone (OdDHL). Functional activation of the LasR protein by diffusion of the OdDHL across the droplet interface was measured by monitoring the expression of green fluorescent protein (GFP) from a LasR-dependent promoter. A threshold concentration of OdDHL was found to induce production of quorum-sensing associated GFP by E. coli. Additionally, we demonstrated that LasR-dependent activation of GFP expression was also initiated when the adjacent droplets contained single E. coli transformed with the OdDHL synthase gene, LasI, representing a simple quorum sensing circuit between two droplets.

  8. Streptococcus massiliensis in the human mouth: a phylogenetic approach for the inference of bacterial habitats.

    PubMed

    Póntigo, F; Silva, C; Moraga, M; Flores, S V

    2015-12-29

    Streptococcus is a diverse bacterial lineage. Species of this genus occupy a myriad of environments inside humans and other animals. Despite the elucidation of several of these habitats, many remain to be identified. Here, we explore a methodological approach to reveal unknown bacterial environments. Specifically, we inferred the phylogeny of the Mitis group by analyzing the sequences of eight genes. In addition, information regarding habitat use of species belonging to this group was obtained from the scientific literature. The oral cavity emerged as a potential, previously unknown, environment of Streptococcus massiliensis. This phylogeny-based prediction was confirmed by species-specific polymerase chain reaction (PCR) amplification. We propose employing a similar approach, i.e., use of bibliographic data and molecular phylogenetics as predictive methods, and species-specific PCR as confirmation, in order to reveal other unknown habitats in further bacterial taxa.

  9. Bacterial pericarditis in a cat

    PubMed Central

    LeBlanc, Nicole; Scollan, Katherine F

    2015-01-01

    Case summary A 4-year-old male neutered domestic shorthair cat was presented to the Oregon State University cardiology service for suspected pericardial effusion. Cardiac tamponade was documented and pericardiocentesis yielded purulent fluid with cytologic results supportive of bacterial pericarditis. The microbial population consisted of Pasteurella multocida, Actinomyces canis, Fusobacterium and Bacteroides species. Conservative management was elected consisting of intravenous antibiotic therapy with ampicillin sodium/sulbactam sodium and metronidazole for 48 h followed by 4 weeks of oral antibiotics. Re-examination 3 months after the initial incident indicated no recurrence of effusion and the cat remained free of clinical signs 2 years after presentation. Relevance and novel information Bacterial pericarditis is a rare cause of pericardial effusion in cats. Growth of P multocida, A canis, Fusobacterium and Bacteroides species has not previously been documented in feline septic pericarditis. Conservative management with broad-spectrum antibiotics may be considered when further diagnostic imaging or exploratory surgery to search for a primary nidus of infection is not feasible or elected. PMID:28491384

  10. Dilemma zone protection and signal coordination at closely-spaced high-speed intersections : final report, November 2001.

    DOT National Transportation Integrated Search

    2001-11-01

    A feasibility study of dilemma zone problems, performed by collecting and analyzing traffic flow data at a high-speed signalized intersection, showed that the maximum green extension or cutback needed to get a vehicle out of the dilemma zone is gener...

  11. Dilemma zone protection and signal coordination at closely-spaced high-speed intersections : executive summary, November 2001.

    DOT National Transportation Integrated Search

    2001-11-01

    A feasibility study of dilemma zone problems, performed by collecting and analyzing traffic flow data at a high-speed signalized intersection, showed that the maximum green extension or cutback needed to get a vehicle out of the dilemma zone is gener...

  12. Role of Sulfhydryl Sites on Bacterial Cell Walls in the Biosorption, Mobility and Bioavailability of Mercury and Uranium

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Myneni, Satish C.; Mishra, Bhoopesh; Fein, Jeremy

    2009-04-01

    The goal of this exploratory study is to provide a quantitative and mechanistic understanding of the impact of bacterial sulfhydryl groups on the bacterial uptake, speciation, methylation and bioavailability of Hg and redox changes of uranium. The relative concentration and reactivity of different functional groups present on bacterial surfaces will be determined, enabling quantitative predictions of the role of biosorption of Hg under the physicochemical conditions found at contaminated DOE sites.The hypotheses we propose to test in this investigation are as follows- 1) Sulfhydryl groups on bacterial cell surfaces modify Hg speciation and solubility, and play an important role, specificallymore » in the sub-micromolar concentration ranges of metals in the natural and contaminated systems. 2) Sulfhydryl binding of Hg on bacterial surfaces significantly influences Hg transport into the cell and the methylation rates by the bacteria. 3) Sulfhydryls on cell membranes can interact with hexavalent uranium and convert to insoluble tetravalent species. 4) Bacterial sulfhydryl surface groups are inducible by the presence of metals during cell growth. Our studies focused on the first hypothesis, and we examined the nature of sulfhydryl sites on three representative bacterial species: Bacillus subtilis, a common gram-positive aerobic soil species; Shewanella oneidensis, a facultative gram-negative surface water species; and Geobacter sulfurreducens, an anaerobic iron-reducing gram-negative species that is capable of Hg methylation; and at a range of Hg concentration (and Hg:bacterial concentration ratio) in which these sites become important. A summary of our findings is as follows- Hg adsorbs more extensively to bacteria than other metals. Hg adsorption also varies strongly with pH and chloride concentration, with maximum adsorption occurring under circumneutral pH conditions for both Cl-bearing and Cl-free systems. Under these conditions, all bacterial species tested

  13. The Nature of Psychology: The Great Dilemmas

    ERIC Educational Resources Information Center

    Ardila, Ruben

    2007-01-01

    Research about the nature of psychology, its subject matter, its level of analysis, its scientific laws, its relationship with other disciplines, and its social relevance has been a matter of great concern and interest during the development of psychology. This problem can be analyzed in terms of the dilemmas of the psychological discipline, which…

  14. Dilemmas of Educational Ethics: Cases and Commentaries

    ERIC Educational Resources Information Center

    Levinson, Meira, Ed.; Fay, Jacob, Ed.

    2016-01-01

    Educators and policy makers confront challenging questions of ethics, justice, and equity on a regular basis. Should teachers retain a struggling student if it means she will most certainly drop out? Should an assignment plan favor middle-class families if it means strengthening the school system for all? These everyday dilemmas are both utterly…

  15. Secrecy: The Communication Dilemma of the CIA.

    ERIC Educational Resources Information Center

    Gibson, Dirk C.

    1987-01-01

    Explores the response of the CIA to public criticism when caught in the dilemma of having to put forth information to the public about its activities and yet carry out secret intelligence-gathering and covert operations. Concludes that its response, attempted cover-ups and censorship, failed due to this conflict in its position. (JC)

  16. Biotic Interactions Shape the Ecological Distributions of Staphylococcus Species.

    PubMed

    Kastman, Erik K; Kamelamela, Noelani; Norville, Josh W; Cosetta, Casey M; Dutton, Rachel J; Wolfe, Benjamin E

    2016-10-18

    Many metagenomic sequencing studies have observed the presence of closely related bacterial species or genotypes in the same microbiome. Previous attempts to explain these patterns of microdiversity have focused on the abiotic environment, but few have considered how biotic interactions could drive patterns of microbiome diversity. We dissected the patterns, processes, and mechanisms shaping the ecological distributions of three closely related Staphylococcus species in cheese rind biofilms. Paradoxically, the most abundant species (S. equorum) is the slowest colonizer and weakest competitor based on growth and competition assays in the laboratory. Through in vitro community reconstructions, we determined that biotic interactions with neighboring fungi help resolve this paradox. Species-specific stimulation of the poor competitor by fungi of the genus Scopulariopsis allows S. equorum to dominate communities in vitro as it does in situ Results of comparative genomic and transcriptomic experiments indicate that iron utilization pathways, including a homolog of the S. aureus staphyloferrin B siderophore operon pathway, are potential molecular mechanisms underlying Staphylococcus-Scopulariopsis interactions. Our integrated approach demonstrates that fungi can structure the ecological distributions of closely related bacterial species, and the data highlight the importance of bacterium-fungus interactions in attempts to design and manipulate microbiomes. Decades of culture-based studies and more recent metagenomic studies have demonstrated that bacterial species in agriculture, medicine, industry, and nature are unevenly distributed across time and space. The ecological processes and molecular mechanisms that shape these distributions are not well understood because it is challenging to connect in situ patterns of diversity with mechanistic in vitro studies in the laboratory. Using tractable cheese rind biofilms and a focus on coagulase-negative staphylococcus (CNS

  17. Live Attenuated Bacterial Vaccines in Aquaculture

    USDA-ARS?s Scientific Manuscript database

    Aquaculture has emerged as an important economical agribusiness, worldwide. Among the top barrier to growth of aquaculture is infectious disease that is causing severe economic losses. Bacterial species of more than 20 genera have been reported as causes of diseases. The risk of disease is often ...

  18. The Importance of the Lateral Prefrontal Cortex for Strategic Decision Making in the Prisoner's Dilemma.

    PubMed

    Soutschek, Alexander; Sauter, Marian; Schubert, Torsten

    2015-12-01

    Previous functional imaging studies investigating the neural basis of strategic decision making in the prisoner's dilemma reported a correlation between cooperative behavior and dorsolateral prefrontal cortex (DLPFC) activity; however, the precise function of the DLPFC in establishing cooperation remains unclear so far. The present study investigated the causal role of the DLPFC in an iterative prisoner's dilemma game with transcranial magnetic stimulation (TMS). We discovered that disrupting the DLPFC with TMS decreased cooperation rates in comparison to control conditions, with this effect being most pronounced when the partner had defected previously. Thus, the current results suggest that the DLPFC contributes to strategic decision making in the prisoner's dilemma game.

  19. Conjunctival bacterial and fungal flora in clinically normal sheep.

    PubMed

    Bonelli, Francesca; Barsotti, Giovanni; Attili, Anna Rita; Mugnaini, Linda; Cuteri, Vincenzo; Preziuso, Silvia; Corazza, Michele; Preziuso, Giovanna; Sgorbini, Micaela

    2014-01-01

    The aim was to identify conjunctival bacterial and fungal flora in clinically normal sheep. Prospective study. Tuscany. 100 eyes from 50 adult Massese female sheep were examined. The sheep included in the study were considered free of anterior ophthalmic abnormalities. Bacteria were identified by morphological assessment, Gram staining, biochemical tests. Identification of filamentous fungi was achieved at the genus level, and Aspergillus species were identified based on keys provided by other authors. Yeast colonies were highlighted, but not identified. Positive cultures were obtained from 100/100 eyes for bacteria, and from 86/100 eyes for fungi. A total of 14 types of bacteria and 5 types of fungi were isolated. Yeasts were isolated from 13/100 eyes. The most frequent fungal isolates were saprophytic fungi. Conjunctival bacterial and fungal flora of clinically normal eyes were reported in sheep. The positivity obtained for conjunctival bacteria was higher compared to findings in the literature by other authors in the same species (100 per cent v 40 per cent), while our results were in line with a recent work performed on mouflons (Ovis Musimon) with a 100 per cent positivity for bacterial conjunctival fornix. In our survey, Gram-positive species were prevalent, as reported by other authors in different species. Few data are available in the literature regarding conjunctival fungal flora in healthy small ruminants. The prevalence of conjunctival fungal flora in this study was higher than findings reported in mouflons (86 per cent v 45 per cent). Differences in fungal prevalence may be due to different methods of managing herds, though further studies are required to verify this hypothesis. The similarities in bacterial and fungal isolates between sheep and mouflons suggest a genera pattern of conjunctival colonisation by bacteria and fungi.

  20. Behavioral and autonomic reactivity to moral dilemmas in frontotemporal dementia versus Alzheimer's disease.

    PubMed

    Fong, Sylvia S; Navarrete, Carlos David; Perfecto, Sean E; Carr, Andrew R; Jimenez, Elvira E; Mendez, Mario F

    2017-08-01

    The personal/impersonal distinction of moral decision-making postulates intuitive emotional responses from medial frontal activity and rational evaluation from lateral frontal activity. This model can be analyzed in behavioral variant frontotemporal dementia (bvFTD), a disorder characterized by impaired emotional intuitions, ventromedial prefrontal cortex (vmPFC) involvement, and relative sparing of lateral frontal regions. Moral dilemmas were presented to 10 bvFTD, 11 Alzheimer's disease (AD), and 9 healthy control (HC) participants while recording skin conductance responses, a measure of emotional arousal. We evaluated their personal versus impersonal conflict, subjective discomfort, and adherence to social norms. Replicating prior work, bvFTD participants were more willing to harm in the personal, but not the impersonal, dilemma compared to AD and HC groups. BvFTD participants had lower arousal and less of an increase in conflict on the personal versus the impersonal dilemma, in contrast to increased arousal and conflict for the AD and HC groups. Furthermore, bvFTD participants verbalized less discomfort, a correlate of low adherence to social norms. These findings support impaired emotional reactions to moral dilemmas in bvFTD and vmPFC lesions and the personal/impersonal model. It suggests a reversion to utilitarian-like considerations when emotional intuition is impaired in the brain.

  1. N-METHYL GROUPS IN BACTERIAL LIPIDS

    PubMed Central

    Goldfine, Howard; Ellis, Martha E.

    1964-01-01

    Goldfine, Howard (Harvard Medical School, Boston, Mass.), and Martha E. Ellis. N-methyl groups in bacterial lipids. J. Bacteriol. 87:8–15. 1964.—The ability of bacteria to synthesize lecithin was examined by measuring the incorporation of the methyl group of methionine into the water-soluble moieties obtained on acid hydrolysis of bacterial lipids. Of 21 species examined, mostly of the order Eubacteriales, only 2, Agrobacterium radiobacter and A. rhizogenes, incorporated the methyl group of methionine into lipid-bound choline. Evidence was also obtained for the formation of lipid-bound N-methylethanolamine and N,N′-dimethylethanolamine in these two organisms. Two other species, Clostridium butyricum and Proteus vulgaris, incorporated the methyl group of methionine into lipid-bound N-methylethanolamine, but did not appear to be able to further methylate these lipids to form lecithin. The results of this study lend further strength to the generalization that bacteria, with the exception of the genus Agrobacterium, are unable to synthesize lecithin. PMID:14102879

  2. A Sociology "of" or a Sociology "for" Education? The New Zealand Experience of the Dilemma

    ERIC Educational Resources Information Center

    Rata, Elizabeth

    2010-01-01

    The sociology of education in New Zealand, as in other countries, is affected by the dilemma inherent to the discipline, namely: is it a sociology "of" education or a sociology "for" education? In this article I analyse three factors in which the dilemma is played out: "cultural oppositionism" in the indigenous…

  3. Bacterial desorption from food container and food processing surfaces.

    PubMed

    McEldowney, S; Fletcher, M

    1988-03-01

    The desorption ofStaphylococcus aureus, Acinetobacter calcoaceticus, and a coryneform from the surfaces of materials used for manufacturing food containers (glass, tin plate, and polypropylene) or postprocess canning factory conveyor belts (stainless steel and nylon) was investigated. The effect of time, pH, temperature, and adsorbed organic layers on desorption was studied.S. aureus did not detach from the substrata at any pH investigated (between pH 5 and 9).A. calcoaceticus and the coryneform in some cases detached, depending upon pH and substratum composition. The degree of bacterial detachment from the substrata was not related to bacterial respiration at experimental pH values. Bacterial desorption was not affected by temperature (4-30°C) nor by an adsorbed layer of peptone and yeast extract on the substrata. The results indicate that bacterial desorption, hence bacterial removal during cleaning or their transfer via liquids flowing over colonized surfaces, is likely to vary with the surface composition and the bacterial species colonizing the surfaces.

  4. Dilemmas of Teaching Inquiry in Elementary Science Methods

    ERIC Educational Resources Information Center

    Newman, William J., Jr.; Abell, Sandra K.; Hubbard, Paula D.; McDonald, James; Otaala, Justine; Martini, Mariana

    2004-01-01

    Because various definitions of inquiry exist in the science education literature and in classroom practice, elementary science methods students and instructors face dilemmas during the study of inquiry. Using field notes, instructor anecdotal notes, student products, and course artifacts, science methods course instructors created fictional…

  5. A novel framework of classical and quantum prisoner's dilemma games on coupled networks.

    PubMed

    Deng, Xinyang; Zhang, Qi; Deng, Yong; Wang, Zhen

    2016-03-15

    Evolutionary games on multilayer networks are attracting growing interest. While among previous studies, the role of quantum games in such a infrastructure is still virgin and may become a fascinating issue across a myriad of research realms. To mimick two kinds of different interactive environments and mechanisms, in this paper a new framework of classical and quantum prisoner's dilemma games on two-layer coupled networks is considered. Within the proposed model, the impact of coupling factor of networks and entanglement degree in quantum games on the evolutionary process has been studied. Simulation results show that the entanglement has no impact on the evolution of the classical prisoner's dilemma, while the rise of the coupling factor obviously impedes cooperation in this game, and the evolution of quantum prisoner's dilemma is greatly impacted by the combined effect of entanglement and coupling.

  6. Genetic difference but functional similarity among fish gut bacterial communities through molecular and biochemical fingerprints.

    PubMed

    Mouchet, Maud A; Bouvier, Corinne; Bouvier, Thierry; Troussellier, Marc; Escalas, Arthur; Mouillot, David

    2012-03-01

    Considering the major involvement of gut microflora in the digestive function of various macro-organisms, bacterial communities inhabiting fish guts may be the main actors of organic matter degradation by fish. Nevertheless, the extent and the sources of variability in the degradation potential of gut bacterial communities are largely overlooked. Using Biolog Ecoplate™ and denaturing gradient gel electrophoresis (DGGE), we explored functional (i.e. the ability to degrade organic matter) and genetic (i.e. identification of DGGE banding patterns) diversity of fish gut bacterial communities, respectively. Gut bacterial communities were extracted from fish species characterized by different diets sampled along a salinity gradient in the Patos-Mirim lagoons complex (Brazil). We found that functional diversity was surprisingly unrelated to genetic diversity of gut bacterial communities. Functional diversity was not affected by the sampling site but by fish species and diet, whereas genetic diversity was significantly influenced by all three factors. Overall, the functional diversity was consistently high across fish individuals and species, suggesting a wide functional niche breadth and a high potential of organic matter degradation. We conclude that fish gut bacterial communities may strongly contribute to nutrient cycling regardless of their genetic diversity and environment. © European Union 2011.

  7. Consequences, norms, and generalized inaction in moral dilemmas: The CNI model of moral decision-making.

    PubMed

    Gawronski, Bertram; Armstrong, Joel; Conway, Paul; Friesdorf, Rebecca; Hütter, Mandy

    2017-09-01

    Research on moral dilemma judgments has been fundamentally shaped by the distinction between utilitarianism and deontology. According to the principle of utilitarianism, the moral status of behavioral options depends on their consequences; the principle of deontology states that the moral status of behavioral options depends on their consistency with moral norms. To identify the processes underlying utilitarian and deontological judgments, researchers have investigated responses to moral dilemmas that pit one principle against the other (e.g., trolley problem). However, the conceptual meaning of responses in this paradigm is ambiguous, because the central aspects of utilitarianism and deontology-consequences and norms-are not manipulated. We illustrate how this shortcoming undermines theoretical interpretations of empirical findings and describe an alternative approach that resolves the ambiguities of the traditional paradigm. Expanding on this approach, we present a multinomial model that allows researchers to quantify sensitivity to consequences (C), sensitivity to moral norms (N), and general preference for inaction versus action irrespective of consequences and norms (I) in responses to moral dilemmas. We present 8 studies that used this model to investigate the effects of gender, cognitive load, question framing, and psychopathy on moral dilemma judgments. The findings obtained with the proposed CNI model offer more nuanced insights into the determinants of moral dilemma judgments, calling for a reassessment of dominant theoretical assumptions. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  8. 77 FR 67380 - Submission for OMB Review; Comment Request: Ethical Dilemmas in Surgery and Utilization of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-09

    ...; Comment Request: Ethical Dilemmas in Surgery and Utilization of Hospital Ethics Consultation Service: A..., unless it displays a currently valid OMB control number. Proposed Collection: Title: Ethical Dilemmas in Surgery and Utilization of Hospital Ethics Consultation Service: A Survey. Type of Information Collection...

  9. A universal surface complexation framework for modeling proton binding onto bacterial surfaces in geologic settings

    USGS Publications Warehouse

    Borrok, D.; Turner, B.F.; Fein, J.B.

    2005-01-01

    Adsorption onto bacterial cell walls can significantly affect the speciation and mobility of aqueous metal cations in many geologic settings. However, a unified thermodynamic framework for describing bacterial adsorption reactions does not exist. This problem originates from the numerous approaches that have been chosen for modeling bacterial surface protonation reactions. In this study, we compile all currently available potentiometric titration datasets for individual bacterial species, bacterial consortia, and bacterial cell wall components. Using a consistent, four discrete site, non-electrostatic surface complexation model, we determine total functional group site densities for all suitable datasets, and present an averaged set of 'universal' thermodynamic proton binding and site density parameters for modeling bacterial adsorption reactions in geologic systems. Modeling results demonstrate that the total concentrations of proton-active functional group sites for the 36 bacterial species and consortia tested are remarkably similar, averaging 3.2 ?? 1.0 (1??) ?? 10-4 moles/wet gram. Examination of the uncertainties involved in the development of proton-binding modeling parameters suggests that ignoring factors such as bacterial species, ionic strength, temperature, and growth conditions introduces relatively small error compared to the unavoidable uncertainty associated with the determination of cell abundances in realistic geologic systems. Hence, we propose that reasonable estimates of the extent of bacterial cell wall deprotonation can be made using averaged thermodynamic modeling parameters from all of the experiments that are considered in this study, regardless of bacterial species used, ionic strength, temperature, or growth condition of the experiment. The average site densities for the four discrete sites are 1.1 ?? 0.7 ?? 10-4, 9.1 ?? 3.8 ?? 10-5, 5.3 ?? 2.1 ?? 10-5, and 6.6 ?? 3.0 ?? 10-5 moles/wet gram bacteria for the sites with pKa values of 3

  10. [The composition of the gastrointestinal bacterial flora of mouse embryos and the placenta tissue bacterial flora].

    PubMed

    Lei, D; Lin, Y; Jiang, X; Lan, L; Zhang, W; Wang, B X

    2017-03-02

    Objective: To explore the composition of the gastrointestinal bacterial flora of mouse embryos and the placenta tissue bacterial flora. Method: Twenty-four specimens were collected from pregnant Kunming mouse including 8 mice of early embryonic (12-13 days) gastrointestinal tissues, 8 cases of late embryonic (19-20 days)gastrointestinal tissues, 8 of late pregnancy placental tissues.The 24 samples were extracted by DNeasy Blood & Tissue kit for high-throughput DNA sequencing. Result: The level of Proteobacteria, Bacteroidetes, Actino-bacteria and Firmicutes were predominantin all specimens.The relative content of predominant bacterial phyla in each group: Proteobacteria (95.00%, 88.14%, 87.26%), Bacteroidetes(1.71%, 2.15%, 2.63%), Actino-Bacteria(1.16%, 4.10%, 3.38%), Firmicutes(0.75%, 2.62%, 2.01%). At the level of family, there were nine predominant bacterial families in which Enterobacteriaeae , Shewanel laceae and Moraxellaceae were dominant.The relative content of dominant bacterial family in eachgroup: Enterobacteriaeae (46.99%, 44.34%, 41.08%), Shewanellaceae (21.99%, 21.10%, 19.05%), Moraxellaceae (9.18%, 7.09%, 5.64%). From the species of flora, the flora from fetal gastrointestinal in early pregnancy and late pregnancy (65.44% and 62.73%) were the same as that from placenta tissue in the late pregnancy.From the abundance of bacteria, at the level of family, the same content of bacteria in three groups accounted for 78.16%, 72.53% and 65.78% respectively. Conclusion: It was proved that the gastrointestinal bacterial flora of mouse embryos and the placenta tissue bacterial flora were colonized. At the same time the bacteria are classified.

  11. Moral dilemmas in surgical training: intent and the case for ethical ambiguity.

    PubMed Central

    Newton, M J

    1986-01-01

    It is often assumed that the central problem in a medical ethics issue is determining which course of action is morally correct. There are some aspects of ethical issues that will yield to such analysis. However, at the core of important medical moral problems is an irreducible dilemma in which all possible courses of action, including inaction, seem ethically unsatisfactory. When facing these issues ethical behaviour depends upon an individual's understanding and acceptance of this painful dilemma without recourse to external moral authority. PMID:3806633

  12. A quantum Samaritan’s dilemma cellular automaton

    PubMed Central

    Situ, Haozhen

    2017-01-01

    The dynamics of a spatial quantum formulation of the iterated Samaritan’s dilemma game with variable entangling is studied in this work. The game is played in the cellular automata manner, i.e. with local and synchronous interaction. The game is assessed in fair and unfair contests, in noiseless scenarios and with disrupting quantum noise. PMID:28680654

  13. Reflections on the ethical dilemmas involved in promoting self-management

    PubMed Central

    Severinsson, Elisabeth

    2014-01-01

    Due to their understanding of self-management, healthcare team members responsible for depressed older persons can experience an ethical dilemma. Each team member contributes important knowledge and experience pertaining to the management of depression, which should be reflected in the management plan. The aim of this study was to explore healthcare team members’ reflections on the ethical dilemmas involved in promoting self-management among depressed older persons. A qualitative design was used and data were collected by means of focus group interviews. The results revealed one main theme: ‘Lack of trust in the community health care system’s commitment to bringing about effectiveness and change, based on three themes; ‘Struggling to ensure the reliable transfer of information about depressed older persons to professionals and family members’, ‘Balancing autonomy, care and dignity’ and ‘Differences in the understanding of responsibility’. Lack of engagement on the part of and trust between the various professional categories who work in the community are extremely counterproductive and have serious implications for patient dignity as well as safety. In conclusion, ethical dilemmas occur when staff members are unable to act in accordance with their professional ethical stance and deliver an appropriate standard of care. PMID:24106261

  14. Symmetry warrants rational cooperation by co-action in Social Dilemmas.

    PubMed

    Sasidevan, V; Sinha, Sitabhra

    2015-08-12

    Is it rational for selfish individuals to cooperate? The conventional answer based on analysis of games such as the Prisoners Dilemma (PD) is that it is not, even though mutual cooperation results in a better outcome for all. This incompatibility between individual rationality and collective benefit lies at the heart of questions about the evolution of cooperation, as illustrated by PD and similar games. Here, we argue that this apparent incompatibility is due to an inconsistency in the standard Nash framework for analyzing non-cooperative games and propose a new paradigm, that of the co-action equilibrium. As in the Nash solution, agents know that others are just as rational as them and taking this into account lead them to realize that others will independently adopt the same strategy, in contrast to the idea of unilateral deviation central to Nash equilibrium thinking. Co-action equilibrium results in better collective outcomes for games representing social dilemmas, with relatively "nicer" strategies being chosen by rational selfish individuals. In particular, the dilemma of PD gets resolved within this framework, suggesting that cooperation can evolve in nature as the rational outcome even for selfish agents, without having to take recourse to additional mechanisms for promoting it.

  15. Experienced speech-language pathologists' responses to ethical dilemmas: an integrated approach to ethical reasoning.

    PubMed

    Kenny, Belinda; Lincoln, Michelle; Balandin, Susan

    2010-05-01

    To investigate the approaches of experienced speech-language pathologists (SLPs) to ethical reasoning and the processes they use to resolve ethical dilemmas. Ten experienced SLPs participated in in-depth interviews. A narrative approach was used to guide participants' descriptions of how they resolved ethical dilemmas. Individual narrative transcriptions were analyzed by using the participant's words to develop an ethical story that described and interpreted their responses to dilemmas. Key concepts from individual stories were then coded into group themes to reflect participants' reasoning processes. Five major themes reflected participants' approaches to ethical reasoning: (a) focusing on the well-being of the client, (b) fulfilling professional roles and responsibilities, (c) attending to professional relationships, (d) managing resources, and (e) integrating personal and professional values. SLPs demonstrated a range of ethical reasoning processes: applying bioethical principles, casuistry, and narrative reasoning when managing ethical dilemmas in the workplace. The results indicate that experienced SLPs adopted an integrated approach to ethical reasoning. They supported clients' rights to make health care choices. Bioethical principles, casuistry, and narrative reasoning provided useful frameworks for facilitating health professionals' application of codes of ethics to complex professional practice issues.

  16. Reagent-free bacterial identification using multivariate analysis of transmission spectra

    NASA Astrophysics Data System (ADS)

    Smith, Jennifer M.; Huffman, Debra E.; Acosta, Dayanis; Serebrennikova, Yulia; García-Rubio, Luis; Leparc, German F.

    2012-10-01

    The identification of bacterial pathogens from culture is critical to the proper administration of antibiotics and patient treatment. Many of the tests currently used in the clinical microbiology laboratory for bacterial identification today can be highly sensitive and specific; however, they have the additional burdens of complexity, cost, and the need for specialized reagents. We present an innovative, reagent-free method for the identification of pathogens from culture. A clinical study has been initiated to evaluate the sensitivity and specificity of this approach. Multiwavelength transmission spectra were generated from a set of clinical isolates including Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Staphylococcus aureus. Spectra of an initial training set of these target organisms were used to create identification models representing the spectral variability of each species using multivariate statistical techniques. Next, the spectra of the blinded isolates of targeted species were identified using the model achieving >94% sensitivity and >98% specificity, with 100% accuracy for P. aeruginosa and S. aureus. The results from this on-going clinical study indicate this approach is a powerful and exciting technique for identification of pathogens. The menu of models is being expanded to include other bacterial genera and species of clinical significance.

  17. Ethical dilemmas, work-related guilt, and posttraumatic stress reactions of news journalists covering the terror attack in Norway in 2011.

    PubMed

    Backholm, Klas; Idås, Trond

    2015-04-01

    News journalists working on crisis-related assignments may experience dilemmas with regard to how to conduct their work without causing additional harm to first-hand victims. In this study, we investigated how exposure to journalistic ethical dilemmas during the Oslo/Utøya terror attack in 2011 and subsequent work-related guilt were related to the development of posttraumatic stress (PTS) reactions. Norwegian journalists (N = 371) covering the terror attack participated in a web-based survey 8-9 months after the incident. We found that females reported more ethical dilemmas during the assignment than males (n = 356, d = 0.51). We also found that being on the scene was not related to more exposure to dilemmas (n = 311, d = 0.01). Moreover, we discovered that work-related guilt had a significant indirect effect on the relationship between exposure to ethical dilemmas and severity of PTS reactions (n = 344, completely standardized indirect effect size = .11, 95% CI [.04, .19]. The results showed that exposure to ethical dilemmas may affect the development of long-term psychological impairment. We concluded that media organizations can prevent postcrisis impairment by preparing employees for possible exposure to dilemmas during crisis-related assignments. Copyright © 2015 Wiley Periodicals, Inc., A Wiley Company.

  18. School Administration: Persistent Dilemmas in Preparation and Practice.

    ERIC Educational Resources Information Center

    Jacobson Stephen L., Ed.; Hickcox, Edward S., Ed.; Stevenson, Robert B., Ed.

    Much of administrative preparation and practice centers on problem solving, developing alternative solutions, and selecting among competing alternatives for the most feasible solutions. Some of the persistent dilemmas resident in the training and the functioning of administrators are examined here by scholars and practitioners of educational…

  19. Tree Leaf Bacterial Community Structure and Diversity Differ along a Gradient of Urban Intensity

    PubMed Central

    Messier, Christian; Kembel, Steven W.

    2017-01-01

    ABSTRACT Tree leaf-associated microbiota have been studied in natural ecosystems but less so in urban settings, where anthropogenic pressures on trees could impact microbial communities and modify their interaction with their hosts. Additionally, trees act as vectors spreading bacterial cells in the air in urban environments due to the density of microbial cells on aerial plant surfaces. Characterizing tree leaf bacterial communities along an urban gradient is thus key to understand the impact of anthropogenic pressures on urban tree-bacterium interactions and on the overall urban microbiome. In this study, we aimed (i) to characterize phyllosphere bacterial communities of seven tree species in urban environments and (ii) to describe the changes in tree phyllosphere bacterial community structure and diversity along a gradient of increasing urban intensity and at two degrees of tree isolation. Our results indicate that, as anthropogenic pressures increase, urban leaf bacterial communities show a reduction in the abundance of the dominant class in the natural plant microbiome, the Alphaproteobacteria. Our work in the urban environment here reveals that the structures of leaf bacterial communities differ along the gradient of urban intensity. The diversity of phyllosphere microbial communities increases at higher urban intensity, also displaying a greater number and variety of associated indicator taxa than the low and medium urban gradient sites. In conclusion, we find that urban environments influence tree bacterial community composition, and our results suggest that feedback between human activity and plant microbiomes could shape urban microbiomes. IMPORTANCE In natural forests, tree leaf surfaces host diverse bacterial communities whose structure and composition are primarily driven by host species identity. Tree leaf bacterial diversity has also been shown to influence tree community productivity, a key function of terrestrial ecosystems. However, most urban

  20. Tree Leaf Bacterial Community Structure and Diversity Differ along a Gradient of Urban Intensity.

    PubMed

    Laforest-Lapointe, Isabelle; Messier, Christian; Kembel, Steven W

    2017-01-01

    Tree leaf-associated microbiota have been studied in natural ecosystems but less so in urban settings, where anthropogenic pressures on trees could impact microbial communities and modify their interaction with their hosts. Additionally, trees act as vectors spreading bacterial cells in the air in urban environments due to the density of microbial cells on aerial plant surfaces. Characterizing tree leaf bacterial communities along an urban gradient is thus key to understand the impact of anthropogenic pressures on urban tree-bacterium interactions and on the overall urban microbiome. In this study, we aimed (i) to characterize phyllosphere bacterial communities of seven tree species in urban environments and (ii) to describe the changes in tree phyllosphere bacterial community structure and diversity along a gradient of increasing urban intensity and at two degrees of tree isolation. Our results indicate that, as anthropogenic pressures increase, urban leaf bacterial communities show a reduction in the abundance of the dominant class in the natural plant microbiome, the Alphaproteobacteria . Our work in the urban environment here reveals that the structures of leaf bacterial communities differ along the gradient of urban intensity. The diversity of phyllosphere microbial communities increases at higher urban intensity, also displaying a greater number and variety of associated indicator taxa than the low and medium urban gradient sites. In conclusion, we find that urban environments influence tree bacterial community composition, and our results suggest that feedback between human activity and plant microbiomes could shape urban microbiomes. IMPORTANCE In natural forests, tree leaf surfaces host diverse bacterial communities whose structure and composition are primarily driven by host species identity. Tree leaf bacterial diversity has also been shown to influence tree community productivity, a key function of terrestrial ecosystems. However, most urban microbiome