bluuebunny/crossref_metadata_2025_split huggingface dataset:
Collective Narcissism and Intergroup Hostility: The Dark Side of ‘In‐Group Love’
Authors: de Zavala Agnieszka Golec 
Published: June 2011

AbstractThis paper reviews current research on intergroup consequences of collective narcissism – an emotional investment in an unrealistic belief in exaggerated greatness of an in‐group. Integrating findings of the psychology of intergroup relations with findings regarding psychological outcomes of individual narcissism, the collective narcissism construct addresses the relationship between ‘in‐group love’ and ‘out‐group hate’. Differentiating between narcissistic and genuine positive group regard uncovers the potential of genuine ‘in‐group’ love to motivate positive out‐group attitudes and intergroup tolerance. Collective narcissism is also shown to be the aspects of positive group attachment that inspires defensive and retaliatory intergroup hostility under perceived threat. Narcissistic idealization of an in‐group is contingent on external validation and underlain by internal doubts. Collective narcissists are never fully satisfied with external acknowledgement of the in‐group and they are sensitive to anything that may undermine the in‐group’s exaggerated image.
Changes on the color parameters of air‐abraded resin composite exposed to different colored beverages
Authors: Gaglianone Livia Aguilera , Martins Joana Dourado , Rossi Thaís Régis Aranha , Saraiva Letícia Oliveira , Cavalcanti Andrea Nóbrega , Mathias Paula 
Published: June 2011

AbstractAim:  To evaluate the effect of prophylaxis using sodium bicarbonate and colored beverages on the color parameters of a resin composite.Methods:  Eighty specimens (Z350–3M ESPE) were randomly allocated into eight groups (n = 10), according to the combination of staining solution (artificial saliva, cola, red wine, or coffee) and air‐powder abrasion with sodium bicarbonate (either performed or not performed). Specimens were immersed in the staining solution for 48 h (two 24‐h cycles). Color evaluation was based on the CIELab system. Two measurements were carried out using a spectrophotometer (Commission Internationale de L’Eclairage L* a* b* system) before and after the immersion period. Final measurement data were analyzed by two‐way anova/Tukey’s test, and comparisons were made between initial and final measurements by anova/Dunnett’s test, with a 5% significance level.Results:  Most comparisons between initial and final measurements were statistically significant. Red wine and coffee significantly affected the color parameters (L*, b*, and ΔE). However, only coffee significantly increased a* values. When compared with untreated surfaces, air‐powder abrasion resulted in alterations of b* and a* parameters, but did not affect L* and ΔE.Conclusions:  Both colored beverage solutions and air‐powder abrasion can affect the color of composite resin restorations.
Increased Transfer of a Multidrug Resistance Plasmid in Escherichia coli Biofilms at the Air-Liquid Interface
Authors: Król Jaroslaw E. , Nguyen Hung Duc , Rogers Linda M. , Beyenal Haluk , Krone Stephen M. , Top Eva M. 
Published: June 2011

ABSTRACT

Although biofilms represent a common bacterial lifestyle in clinically and environmentally important habitats, there is scant information on the extent of gene transfer in these spatially structured populations. The objective of this study was to gain insight into factors that affect transfer of the promiscuous multidrug resistance plasmid pB10 in
Escherichia coli
biofilms. Biofilms were grown in different experimental settings, and plasmid transfer was monitored using laser scanning confocal microscopy and plate counting. In closed flow cells, plasmid transfer in surface-attached submerged biofilms was negligible. In contrast, a high plasmid transfer efficiency was observed in a biofilm floating at the air-liquid interface in an open flow cell with low flow rates. A vertical flow cell and a batch culture biofilm reactor were then used to detect plasmid transfer at different depths away from the air-liquid interface. Extensive plasmid transfer occurred only in a narrow zone near that interface. The much lower transfer frequencies in the lower zones coincided with rapidly decreasing oxygen concentrations. However, when an
E. coli
csrA
mutant was used as the recipient, a thick biofilm was obtained at all depths, and plasmid transfer occurred at similar frequencies throughout. These results and data from separate aerobic and anaerobic matings suggest that oxygen can affect IncP-1 plasmid transfer efficiency, not only directly but also indirectly, through influencing population densities and therefore colocalization of donors and recipients. In conclusion, the air-liquid interface can be a hot spot for plasmid-mediated gene transfer due to high densities of juxtaposed donor and recipient cells.
Large-Scale Comparative Phenotypic and Genomic Analyses Reveal Ecological Preferences of Shewanella Species and Identify Metabolic Pathways Conserved at the Genus Level
Authors: Rodrigues Jorge L. M. , Serres Margrethe H. , Tiedje James M. 
Published: June 2011

ABSTRACTThe use of comparative genomics for the study of different microbiological species has increased substantially as sequence technologies become more affordable. However, efforts to fully link a genotype to its phenotype remain limited to the development of one mutant at a time. In this study, we provided a high-throughput alternative to this limiting step by coupling comparative genomics to the use of phenotype arrays for five sequencedShewanellastrains. Positive phenotypes were obtained for 441 nutrients (C, N, P, and S sources), with N-based compounds being the most utilized for all strains. Many genes and pathways predicted by genome analyses were confirmed with the comparative phenotype assay, and three degradation pathways believed to be missing inShewanellawere confirmed as missing. A number of previously unknown gene products were predicted to be parts of pathways or to have a function, expanding the number of gene targets for future genetic analyses. Ecologically, the comparative high-throughput phenotype analysis provided insights into niche specialization among the five different strains. For example,Shewanella amazonensisstrain SB2B, isolated from the Amazon River delta, was capable of utilizing 60 C compounds, whereasShewanellasp. strain W3-18-1, isolated from deep marine sediment, utilized only 25 of them. In spite of the large number of nutrient sources yielding positive results, our study indicated that except for the N sources, they were not sufficiently informative to predict growth phenotypes from increasing evolutionary distances. Our results indicate the importance of phenotypic evaluation for confirming genome predictions. This strategy will accelerate the functional discovery of genes and provide an ecological framework for microbial genome sequencing projects.
Discovery of a Gene Involved in a Third Bacterial Protoporphyrinogen Oxidase Activity through Comparative Genomic Analysis and Functional Complementation
Authors: Boynton Tye O. , Gerdes Svetlana , Craven Sarah H. , Neidle Ellen L. , Phillips John D. , Dailey Harry A. 
Published: June 2011

ABSTRACT

Tetrapyrroles are ubiquitous molecules in nearly all living organisms. Heme, an iron-containing tetrapyrrole, is widely distributed in nature, including most characterized aerobic and facultative bacteria. A large majority of bacteria that contain heme possess the ability to synthesize it. Despite this capability and the fact that the biosynthetic pathway has been well studied, enzymes catalyzing at least three steps have remained “missing” in many bacteria. In the current work, we have employed comparative genomics via the SEED genomic platform, coupled with experimental verification utilizing
Acinetobacter baylyi
ADP1, to identify one of the missing enzymes, a new protoporphyrinogen oxidase, the penultimate enzyme in heme biosynthesis. COG1981 was identified by genomic analysis as a candidate protein family for the missing enzyme in bacteria that lacked HemG or HemY, two known protoporphyrinogen oxidases. The predicted amino acid sequence of COG1981 is unlike those of the known enzymes HemG and HemY, but in some genomes, the gene encoding it is found neighboring other heme biosynthetic genes. When the COG1981 gene was deleted from the genome of
A. baylyi
, a bacterium that lacks both
hemG
and
hemY
, the organism became auxotrophic for heme. Cultures accumulated porphyrin intermediates, and crude cell extracts lacked protoporphyrinogen oxidase activity. The heme auxotrophy was rescued by the presence of a plasmid-borne protoporphyrinogen oxidase gene from a number of different organisms, such as
hemG
from
Escherichia coli
,
hemY
from
Myxococcus xanthus
, or the human gene for protoporphyrinogen oxidase.
Potentially Human-Pathogenic Escherichia coli O26 in Norwegian Sheep Flocks
Authors: Sekse C. , Sunde M. , Lindstedt B.-A. , Hopp P. , Bruheim T. , Cudjoe K. S. , Kvitle B. , Urdahl A. M. 
Published: June 2011

ABSTRACT

A national survey of
Escherichia coli
O26 in Norwegian sheep flocks was conducted, using fecal samples to determine the prevalence. In total, 491 flocks were tested, and
E. coli
O26 was detected in 17.9% of the flocks. One hundred forty-two
E. coli
O26 isolates were examined for flagellar antigens (H typing) and four virulence genes, including
stx
and
eae
, to identify possible Shiga toxin-producing
E. coli
(STEC) and enteropathogenic
E. coli
(EPEC). Most isolates (129 out of 142) were identified as
E. coli
O26:H11. They possessed
eae
and may have potential as human pathogens, although only a small fraction were identified as STEC O26:H11, giving a prevalence in sheep flocks of only 0.8%. Correspondingly, the sheep flock prevalence of atypical EPEC (aEPEC) O26:H11 was surprisingly high (15.9%). The genetic relationship between the
E. coli
O26:H11 isolates was investigated by pulsed-field gel electrophoresis (PFGE) and multilocus variable number tandem repeat analysis (MLVA), identifying 63 distinct PFGE profiles and 22 MLVA profiles. Although the MLVA protocol was less discriminatory than PFGE and a few cases of disagreement were observed, comparison by partition mapping showed an overall good accordance between the two methods. A close relationship between a few isolates of aEPEC O26:H11 and STEC O26:H11 was identified, but all the
E. coli
O26:H11 isolates should be considered potentially pathogenic to humans. The present study consisted of a representative sampling of sheep flocks from all parts of Norway. This is the first large survey of sheep flocks focusing on
E. coli
O26 in general, including results of STEC, aEPEC, and nonpathogenic isolates.
Global Gene Expression Profile for Swarming Bacillus cereus Bacteria
Authors: Salvetti Sara , Faegri Karoline , Ghelardi Emilia , Kolstø Anne-Brit , Senesi Sonia 
Published: June 2011

ABSTRACT

Bacillus cereus
can use swarming to move over and colonize solid surfaces in different environments. This kind of motility is a collective behavior accompanied by the production of long and hyperflagellate swarm cells. In this study, the genome-wide transcriptional response of
B. cereus
ATCC 14579 during swarming was analyzed. Swarming was shown to trigger the differential expression (>2-fold change) of 118 genes. Downregulated genes included those required for basic cellular metabolism. In accordance with the hyperflagellate phenotype of the swarm cell, genes encoding flagellin were overexpressed. Some genes associated with K
+
transport, phBC6A51 phage genes, and the binding component of the enterotoxin hemolysin BL (HBL) were also induced. Quantitative reverse transcription-PCR (qRT-PCR) experiments indicated an almost 2-fold upregulation of the entire
hbl
operon during swarming. Finally, BC1435 and BC1436, orthologs of
liaI-liaH
that are known to be involved in the resistance of
Bacillus subtilis
to daptomycin, were upregulated under swarming conditions. Accordingly, phenotypic assays showed reduced susceptibility of swarming
B. cereus
cells to daptomycin, and P

spac

-induced hyper-expression of these genes in liquid medium highlighted the role of BC1435 and BC1436 in the response of
B. cereus
to daptomycin.
Redesigning Escherichia coli Metabolism for Anaerobic Production of Isobutanol
Authors: Trinh Cong T. , Li Johnny , Blanch Harvey W. , Clark Douglas S. 
Published: June 2011

ABSTRACT

Fermentation enables the production of reduced metabolites, such as the biofuels ethanol and butanol, from fermentable sugars. This work demonstrates a general approach for designing and constructing a production host that uses a heterologous pathway as an obligately fermentative pathway to produce reduced metabolites, specifically, the biofuel isobutanol. Elementary mode analysis was applied to design an
Escherichia coli
strain optimized for isobutanol production under strictly anaerobic conditions. The central metabolism of
E. coli
was decomposed into 38,219 functional, unique, and elementary modes (EMs). The model predictions revealed that during anaerobic growth
E. coli
cannot produce isobutanol as the sole fermentative product. By deleting 7 chromosomal genes, the total 38,219 EMs were constrained to 12 EMs, 6 of which can produce high yields of isobutanol in a range from 0.29 to 0.41 g isobutanol/g glucose under anaerobic conditions. The remaining 6 EMs rely primarily on the pyruvate dehydrogenase enzyme complex (PDHC) and are typically inhibited under anaerobic conditions. The redesigned
E. coli
strain was constrained to employ the anaerobic isobutanol pathways through deletion of 7 chromosomal genes, addition of 2 heterologous genes, and overexpression of 5 genes. Here we present the design, construction, and characterization of an isobutanol-producing
E. coli
strain to illustrate the approach. The model predictions are evaluated in relation to experimental data and strategies proposed to improve anaerobic isobutanol production. We also show that the endogenous alcohol/aldehyde dehydrogenase AdhE is the key enzyme responsible for the production of isobutanol and ethanol under anaerobic conditions. The glycolytic flux can be controlled to regulate the ratio of isobutanol to ethanol production.
Electroactivity of Phototrophic River Biofilms and Constitutive Cultivable Bacteria
Authors: Lyautey Emilie , Cournet Amandine , Morin Soizic , Boulêtreau Stéphanie , Etcheverry Luc , Charcosset Jean-Yves , Delmas François , Bergel Alain , Garabetian Frédéric 
Published: June 2011

ABSTRACT

Electroactivity is a property of microorganisms assembled in biofilms that has been highlighted in a variety of environments. This characteristic was assessed for phototrophic river biofilms at the community scale and at the bacterial population scale. At the community scale, electroactivity was evaluated on stainless steel and copper alloy coupons used both as biofilm colonization supports and as working electrodes. At the population scale, the ability of environmental bacterial strains to catalyze oxygen reduction was assessed by cyclic voltammetry. Our data demonstrate that phototrophic river biofilm development on the electrodes, measured by dry mass and chlorophyll
a
content, resulted in significant increases of the recorded potentials, with potentials of up to +120 mV/saturated calomel electrode (SCE) on stainless steel electrodes and +60 mV/SCE on copper electrodes. Thirty-two bacterial strains isolated from natural phototrophic river biofilms were tested by cyclic voltammetry. Twenty-five were able to catalyze oxygen reduction, with shifts of potential ranging from 0.06 to 0.23 V, cathodic peak potentials ranging from −0.36 to −0.76 V/SCE, and peak amplitudes ranging from −9.5 to −19.4 μA. These isolates were diversified phylogenetically (
Actinobacteria
,
Firmicutes
,
Bacteroidetes
, and
Alpha
-,
Beta
-, and
Gammaproteobacteria
) and exhibited various phenotypic properties (Gram stain, oxidase, and catalase characteristics). These data suggest that phototrophic river biofilm communities and/or most of their constitutive bacterial populations present the ability to promote electronic exchange with a metallic electrode, supporting the following possibilities: (i) development of electrochemistry-based sensors allowing
in situ
phototrophic river biofilm detection and (ii) production of microbial fuel cell inocula under oligotrophic conditions.
Statistical Analysis of Long- and Short-Range Forces Involved in Bacterial Adhesion to Substratum Surfaces as Measured Using Atomic Force Microscopy
Authors: Chen Yun , Busscher Henk J. , van der Mei Henny C. , Norde Willem 
Published: June 2011

ABSTRACT
Surface thermodynamic analyses of microbial adhesion using measured contact angles on solid substrata and microbial cell surfaces are widely employed to determine the nature of the adhesion forces, i.e., the interplay between Lifshitz-van der Waals and acid-base forces. While surface thermodynamic analyses are often viewed critically, atomic force microscopy (AFM) can also provide information on the nature of the adhesion forces by means of Poisson analysis of the measured forces. This review first presents a description of Poisson analysis and its underlying assumptions. The data available from the literature for different combinations of bacterial strains and substrata are then summarized, leading to the conclusion that bacterial adhesion to surfaces is generally dominated by short-range, attractive acid-base interactions, in combination with long-range, weaker Lifshitz-van der Waals forces. This is in line with the findings of surface thermodynamic analyses of bacterial adhesion. Comparison with single-molecule ligand-receptor forces from the literature suggests that the short-range-force contribution from Poisson analysis involves a discrete adhesive bacterial cell surface site rather than a single molecular force. The adhesion force arising from these cell surface sites and the number of sites available may differ from strain to strain. Force spectroscopy, however, involves the tedious task of identifying the minor peaks in the AFM retraction force-distance curve. This step can be avoided by carrying out Poisson analysis on the work of adhesion, which can also be derived from retraction force-distance curves. This newly proposed way of performing Poisson analysis confirms that multiple molecular bonds, rather than a single molecular bond, contribute to a discrete adhesive bacterial cell surface site.
Identification of Loci and Functional Characterization of Trichothecene Biosynthesis Genes in Filamentous Fungi of the Genus Trichoderma
Authors: Cardoza R. E. , Malmierca M. G. , Hermosa M. R. , Alexander N. J. , McCormick S. P. , Proctor R. H. , Tijerino A. M. , Rumbero A. , Monte E. , Gutiérrez S. 
Published: June 2011

ABSTRACT

Trichothecenes are mycotoxins produced by
Trichoderma
,
Fusarium
, and at least four other genera in the fungal order
Hypocreales
.
Fusarium
has a trichothecene biosynthetic gene (
TRI
) cluster that encodes transport and regulatory proteins as well as most enzymes required for the formation of the mycotoxins. However, little is known about trichothecene biosynthesis in the other genera. Here, we identify and characterize
TRI
gene orthologues (
tri
) in
Trichoderma arundinaceum
and
Trichoderma brevicompactum
. Our results indicate that both
Trichoderma
species have a
tri
cluster that consists of orthologues of seven genes present in the
Fusarium
TRI
cluster. Organization of genes in the cluster is the same in the two
Trichoderma
species but differs from the organization in
Fusarium
. Sequence and functional analysis revealed that the gene (
tri5
) responsible for the first committed step in trichothecene biosynthesis is located outside the cluster in both
Trichoderma
species rather than inside the cluster as it is in
Fusarium
. Heterologous expression analysis revealed that two
T. arundinaceum
cluster genes (
tri4
and
tri11
) differ in function from their
Fusarium
orthologues. The
Tatri4
-encoded enzyme catalyzes only three of the four oxygenation reactions catalyzed by the orthologous enzyme in
Fusarium
. The
Tatri11
-encoded enzyme catalyzes a completely different reaction (trichothecene C-4 hydroxylation) than the
Fusarium
orthologue (trichothecene C-15 hydroxylation). The results of this study indicate that although some characteristics of the
tri/TRI
cluster have been conserved during evolution of
Trichoderma
and
Fusarium
, the cluster has undergone marked changes, including gene loss and/or gain, gene rearrangement, and divergence of gene function.
Role of Nitric Oxide and Flavohemoglobin Homolog Genes in Aspergillus nidulans Sexual Development and Mycotoxin Production
Authors: Baidya Sachin , Cary Jeffrey W. , Grayburn W. Scott , Calvo A. M. 
Published: June 2011

ABSTRACT

Flavohemoglobins are widely distributed in both prokaryotes and eukaryotes. These proteins are involved in reducing nitric oxide levels. Deletion of the
Aspergillus nidulans
flavohemoglobin gene
fhbA
induced sexual development and decreased sterigmatocystin production. Supplementation with a nitric oxide-releasing compound promoted cleistothecial formation and increased
nsdD
and
steA
expression, indicating that nitric oxide induces sexual development. This is the first study on the effect of nitric oxide on morphogenesis and secondary metabolism in fungi.
Determination of Microbial Diversity of Aeromonas Strains on the Basis of Multilocus Sequence Typing, Phenotype, and Presence of Putative Virulence Genes
Authors: Martino Maria Elena , Fasolato Luca , Montemurro Filomena , Rosteghin Marina , Manfrin Amedeo , Patarnello Tomaso , Novelli Enrico , Cardazzo Barbara 
Published: June 2011

ABSTRACT

The genus
Aeromonas
has been described as comprising several species associated with the aquatic environment, which represents their principal reservoir.
Aeromonas
spp. are commonly isolated from diseased and healthy fish, but the involvement of such bacteria in human infection and gastroenteritis has frequently been reported. The primary challenge in establishing an unequivocal link between the
Aeromonas
genus and pathogenesis in humans is the extremely complicated taxonomy. With the aim of clarifying taxonomic relationships among the strains and phenotypes, a multilocus sequencing approach was developed and applied to characterize 23 type and reference strains of
Aeromonas
spp. and a collection of 77 field strains isolated from fish, crustaceans, and mollusks. All strains were also screened for putative determinants of virulence by PCR (
ast
,
ahh1
,
act
,
asa1
,
eno
,
ascV
, and
aexT
) and the production of acylated homoserine lactones (AHLs). In addition, the phenotypic fingerprinting obtained from 29 biochemical tests was submitted to the nonparametric combination (NPC) test methodology to define the statistical differences among the identified genetic clusters. Multilocus sequence typing (MLST) achieved precise strain genotyping, and the phylogenetic analysis of concatenated sequences delineated the relationship among the taxa belonging to the genus
Aeromonas
, providing a powerful tool for outbreak traceability, host range diffusion, and ecological studies. The NPC test showed the feasibility of phenotypic differentiation among the majority of the MLST clusters by using a selection of tests or the entire biochemical fingerprinting. A Web-based MLST sequence database (
http://pubmlst.org/aeromonas
) specific for the
Aeromonas
genus was developed and implemented with all the results.