bluuebunny/crossref_metadata_2025 huggingface dataset:
Flattening of Caribbean coral reefs: region-wide declines in architectural complexity
Authors: Alvarez-Filip Lorenzo , Dulvy Nicholas K. , Gill Jennifer A. , Côté Isabelle M. , Watkinson Andrew R.
Published: June 2009

Coral reefs are rich in biodiversity, in large part because their highly complex architecture provides shelter and resources for a wide range of organisms. Recent rapid declines in hard coral cover have occurred across the Caribbean region, but the concomitant consequences for reef architecture have not been quantified on a large scale to date. We provide, to our knowledge, the first region-wide analysis of changes in reef architectural complexity, using nearly 500 surveys across 200 reefs, between 1969 and 2008. The architectural complexity of Caribbean reefs has declined nonlinearly with the near disappearance of the most complex reefs over the last 40 years. The flattening of Caribbean reefs was apparent by the early 1980s, followed by a period of stasis between 1985 and 1998 and then a resumption of the decline in complexity to the present. Rates of loss are similar on shallow (<6 m), mid-water (6–20 m) and deep (>20 m) reefs and are consistent across all five subregions. The temporal pattern of declining architecture coincides with key events in recent Caribbean ecological history: the loss of structurally complex
Acropora
corals, the mass mortality of the grazing urchin
Diadema antillarum
and the 1998 El Nino Southern Oscillation-induced worldwide coral bleaching event. The consistently low estimates of current architectural complexity suggest regional-scale degradation and homogenization of reef structure. The widespread loss of architectural complexity is likely to have serious consequences for reef biodiversity, ecosystem functioning and associated environmental services.
Food-chain length and adaptive foraging
Authors: Kondoh Michio , Ninomiya Kunihiko
Published: June 2009

Food-chain length, the number of feeding links from the basal species to the top predator, is a key characteristic of biological communities. However, the determinants of food-chain length still remain controversial. While classical theory predicts that food-chain length should increase with increasing resource availability, empirical supports of this prediction are limited to those from simple, artificial microcosms. A positive resource availability–chain length relationship has seldom been observed in natural ecosystems. Here, using a theoretical model, we show that those correlations, or no relationships, may be explained by considering the dynamic food-web reconstruction induced by predator's adaptive foraging. More specifically, with foraging adaptation, the food-chain length becomes relatively invariant, or even decreases with increasing resource availability, in contrast to a non-adaptive counterpart where chain length increases with increasing resource availability; and that maximum chain length more sharply decreases with resource availability either when species richness is higher or potential link number is larger. The interactive effects of resource availability, adaptability and community complexity may explain the contradictory effects of resource availability in simple microcosms and larger ecosystems. The model also explains the recently reported positive effect of habitat size on food-chain length as a result of increased species richness and/or decreased connectance owing to interspecific spatial segregation.
Are insect pollinators more generalist than insect herbivores?
Authors: Fontaine Colin , Thébault Elisa , Dajoz Isabelle
Published: June 2009

Recent community-level studies have acknowledged that generalist species are more widespread than previously thought and highlighted their preponderant impact on community functioning and evolution. It is suggested that the type of interaction, trophic versus mutualistic, should affect species generalization level; however, no direct comparison has been made yet. Here, we performed such a comparison using 44 plant–insect networks describing either pollination or herbivory communities. Our analysis shows that the type of interaction does indeed have an impact on various aspects of species generalism, from the distribution of generalism in the community to the phylogenetic diversity of the plants with which a given insect species interacts. However, the amplitude of the observed differences depends on the aspect of species generalism studied. While the non-quantitative and quantitative measures of generalism suggest that pollinators interact with more plant species and more evenly than herbivores, phylogenetic measures clearly show that herbivores interact with plant species far more closely related to each other than pollinators. This comparative approach offers a promising perspective to better understand the functioning and evolution of multispecies assemblages by pointing out some fundamental singularities of communities depending on the type of interaction considered.
Increases in air temperature can promote wind-driven dispersal and spread of plants
Authors: Kuparinen Anna , Katul Gabriel , Nathan Ran , Schurr Frank M.
Published: June 2009

Long-distance dispersal (LDD) of seeds and pollen shapes the spatial dynamics of plant genotypes, populations and communities. Quantifying LDD is thus important for predicting the future dynamics of plants exposed to environmental changes. However, environmental changes can also alter the behaviour of LDD vectors: for instance, increasing air temperature may enhance atmospheric instability, thereby altering the turbulent airflow that transports seed and pollen. Here, we investigate temperature effects on wind dispersal in a boreal forest using a 10-year time series of micrometeorological measurements and a Lagrangian stochastic model for particle transport. For a wide range of dispersal and life history types, we found positive relations between air temperature and LDD. This translates into a largely consistent positive effect of +3°C warming on predicted LDD frequencies and spread rates of plants. Relative increases in LDD frequency tend to be higher for heavy-seeded plants, whereas absolute increases in LDD and spread rates are higher for light-seeded plants for which wind is often an important dispersal vector. While these predicted increases are not sufficient to compensate forecasted range losses and environmental changes can alter plant spread in various ways, our results generally suggest that warming can promote wind-driven movements of plant genotypes and populations in boreal forests.
Courtship raises male fertilization success through post-mating sexual selection in a spider
Authors: Schneider Jutta M. , Lesmono Kristiani
Published: June 2009

Courtship is well known for its positive effects on mating success. However, in polyandrous species, sexual selection continues to operate after copulation. Cryptic female choice is expected under unpredictable mating rates in combination with sequential mate encounters. However, there are very few accounts of the effects of courtship on cryptic female choice, and the available evidence is often correlative.

Mature
Argiope bruennichi
females are always receptive and never attack or reject males before mating, although sexual cannibalism after mating occurs regularly. Still, males usually perform an energetic vibratory display prior to copulation. We tested the hypothesis that beneficial effects of courtship arise cryptically, during or after mating, resulting in increased paternity success under polyandry. Manipulating courtship duration experimentally, we found that males that mated without display had a reduced paternity share even though no differences in post-copulatory cannibalism or copulation duration were detected. This suggests that the paternity advantage associated with courtship arose through female-mediated processes after intromission, meeting the definition of cryptic female choice.
The origin of ascophoran bryozoans was historically contingent but likely
Authors: Dick Matthew H. , Lidgard Scott , Gordon Dennis P. , Mawatari Shunsuke F.
Published: June 2009

The degree to which evolutionary outcomes are historically contingent remains unresolved, with studies at different levels of the biological hierarchy reaching different conclusions. Here we examine historical contingency in the origin of two evolutionary novelties in bryozoans, a phylum of colonial animals whose fossil record is as complete as that of any major group. In cheilostomes, the dominant living bryozoans, key innovations were the costal shield and ascus, which first appeared in the Cretaceous 85–95 Myr ago. We establish the parallel origin of these structures less than 12 Myr ago in an extant bryozoan genus,
Cauloramphus
, with transitional stages remarkably similar to those inferred for a Cretaceous clade. By one measure, long lag times in the first origins of costal shield and ascus suggest a high degree of historical contingency. This, however, does not equate with dependence on a narrow set of initial conditions or a low probability of evolution. More than one set of initial conditions may lead to an evolutionary outcome, and alternative sets are not entirely independent. We argue that, although historically contingent, the origin of ascus and costal shield was highly likely with sufficient possibilities afforded by time.
An onychodont fish (Osteichthyes, Sarcopterygii) from the Early Devonian of China, and the evolution of the Onychodontiformes
Authors: Lu Jing , Zhu Min
Published: June 2009

Although the superbly preserved specimens ofOnychodus jandemarraihave greatly advanced our understanding of the Onychodontiformes, a primitive sarcopterygian group with large parasymphysial tooth whorls, the scarcity of the otoccipital material in the group hampers further morphological comparisons between onychodonts and other sarcopterygian groups. Here we report a new onychodontQingmenodus yuigen. et sp. nov. from the Early Devonian (Pragian) of South China that comprises well-ossified otoccipital and upper and lower jaw material. As one of the oldest known onychodonts,Qingmenodusshows for the first time the nearly complete structure of the otoccipital in onychodonts and provides an additional basis to address the phylogenetic position of the group. Its elongated otic shelf exhibits the posterior shift of the attachment for the basicranial muscle as in coelacanths and sheds light on the feeding mechanism of onychodonts.Qingmenodusdisplays a mosaic of primitive and derived onychodont features. The phylogenetic analysis placesQingmenodusimmediately basal to the clade comprisingOnychodusandGrossius.
Signals of major histocompatibility complex overdominance in a wild salmonid population
Authors: Kekäläinen Jukka , Vallunen J. Albert , Primmer Craig R. , Rättyä Jouni , Taskinen Jouni
Published: June 2009

The major histocompatibility complex (MHC) contains the most variable genes in vertebrates, but despite extensive research, the mechanisms maintaining this polymorphism are still unresolved. One hypothesis is that MHC polymorphism is a result of balancing selection operating by overdominance, but convincing evidence for overdominant selection in natural populations has been lacking. We present strong evidence consistent with MHC-specific overdominance in a free-living population of Arctic charr (Salvelinus alpinus) in northernmost Europe. In this population, where just two MHC alleles were observed, MHC heterozygous fish had a lower parasite load, were in better condition (as estimated by a fatness indicator) and had higher survival under stress than either of the homozygotes. Conversely, there was no consistent association between these fitness measures and assumedly neutral microsatellite variability, indicating an MHC-specific effect. Our results provide convincing empirical evidence consistent with the notion that overdominance can be an important evolutionary mechanism contributing to MHC polymorphism in wild animal populations. They also support a recent simulation study indicating that the number of alleles expected to be maintained at an MHC loci can be low, even under strong heterozygote advantage.
Global latitudinal variations in marine copepod diversity and environmental factors
Authors: Rombouts Isabelle , Beaugrand Grégory , Ibaňez Frédéric , Gasparini Stéphane , Chiba Sanae , Legendre Louis
Published: June 2009

Latitudinal gradients in diversity are among the most striking features in ecology. For terrestrial species, climate (i.e. temperature and precipitation) is believed to exert a strong influence on the geographical distributions of diversity through its effects on energy availability. Here, we provide the first global description of geographical variation in the diversity of marine copepods, a key trophic link between phytoplankton and fish, in relation to environmental variables. We found a polar–tropical difference in copepod diversity in the Northern Hemisphere where diversity peaked at subtropical latitudes. In the Southern Hemisphere, diversity showed a tropical plateau into the temperate regions. This asymmetry around the Equator may be explained by climatic conditions, in particular the influence of the Inter-Tropical Convergence Zone, prevailing mainly in the northern tropical region. Ocean temperature was the most important explanatory factor among all environmental variables tested, accounting for 54 per cent of the variation in diversity. Given the strong positive correlation between diversity and temperature, local copepod diversity, especially in extra-tropical regions, is likely to increase with climate change as their large-scale distributions respond to climate warming.
Emergence of carbapenem-non-susceptible extended-spectrum β-lactamase-producing Klebsiella pneumoniae isolates at the university hospital of Tübingen, Germany
Authors: Gröbner Sabine , Linke Dirk , Schütz Wolfgang , Fladerer Claudia , Madlung Johannes , Autenrieth Ingo B. , Witte Wolfgang , Pfeifer Yvonne
Published: June 2009

The spread of Gram-negative bacteria with plasmid-borne extended-spectrumβ-lactamases (ESBLs) has become a worldwide problem. This study analysed a total of 366 ESBL-producingEnterobacteriaceaestrains isolated from non-selected patient specimens at the university hospital of Tübingen in the period January 2003 to December 2007. Although the overall ESBL rate was comparatively low (1.6 %), the percentages of ESBL-producingEnterobacterspp. andEscherichia coliincreased from 0.8 and 0.5 %, respectively, in 2003 to 4.6 and 3.8 % in 2007. In particular, the emergence was observed of one carbapenem-resistant ESBL-producingE. coliisolate and five carbapenem-non-susceptible ESBL-positiveKlebsiella pneumoniaeisolates, in two of which carbapenem resistance development was documentedin vivounder a meropenem-containing antibiotic regime. The possible underlying mechanism for this carbapenem resistance in three of theK. pneumoniaeisolates was loss of theKlebsiellaporin channel protein OmpK36 as shown by PCR analysis. The remaining twoK. pneumoniaeisolates exhibited increased expression of a tripartite AcrAB–TolC efflux pump as demonstrated by SDS-PAGE and mass spectrometry analysis of bacterial outer-membrane extracts, which, in addition to other unknown mechanisms, may contribute towards increasing the carbapenem MIC values further. Carbapenem-non-susceptible ESBL isolates may pose a new problem in the future due to possible outbreak situations and limited antibiotic treatment options. Therefore, a systematic exploration of intestinal colonization with ESBL isolates should be reconsidered, at least for haemato-oncological departments from where four of the five carbapenem-non-susceptible ESBL isolates originated.
Immune effects against influenza A virus and a novel DNA vaccine with co-expression of haemagglutinin- and neuraminidase-encoding genes
Authors: Zhang Weidong , Li Wanyi , Li Yan , Li Hong , Wang Baoning , Wang Fengping , Zhu Yuanjun , Jiang Zhonghua , Zhong Li , Li Mingyuan
Published: June 2009

The high variability of influenza virus causes difficulties in the control and prevention of influenza, thus seeking a promising approach for dealing with these problems is a hot topic. Haemagglutinin (HA) and neuraminidase (NA) are major surface antigens of the influenza virus, and provide effective protection against lethal challenges with this virus. We constructed a DNA vaccine (pHA-IRES2-NA) that co-expressed both HA and NA, and compared its protective efficacy and immunogenic ability with that of singly expressed HA or NA, or a mixture of the two singly expressed proteins. Our findings showed that both HA and NA proteins expressed by pHA-IRES2-NA could be detectedin vivoandin vitro. The protection of DNA vaccines was evaluated by serum antibody titres, residual lung virus titres and survival rates of the mice. In the murine model, immunization of pHA-IRES2-NA generated significant anti-HA and anti-NA antibody, increased the percentage of CD8+cells and gamma interferon-producing CD8+cells and the ratio of Th1/Th2 (T helper) cells, which was comparable to the effects of immunization withHAorNADNA alone or with a mixture ofHAandNADNA. All the mice inoculated by pHA-IRES2-NA resisted the lethal challenge by homologous influenza virus and survived with low lung virus titre. In addition, previous studies reported that co-expression allowed higher-frequency transduction compared to co-transduction of separated vector systems encoding different genes. The novel HA and NA co-expression DNA vaccine is a successful alternative to using a mixture of purified HA and NA proteins orHAandNADNA.
Escherichia coli O123 O antigen genes and polysaccharide structure are conserved in some Salmonella enterica serogroups
Authors: Clark Clifford G. , Kropinski Andrew M. , Parolis Haralambos , Grant Christopher C. R. , Trout-Yakel Keri M. , Franklin Kristyn , Ng Lai-King , Paramonov Nikolay A. , Parolis Lesley A. S. , Rahn Kris , Tabor Helen
Published: June 2009

The serotyping of O and H antigens is an important first step in the characterization of Salmonella enterica. However, serotyping has become increasingly technically demanding and expensive to perform. We have therefore sequenced additional S. enterica O antigen gene clusters to provide information for the development of DNA-based serotyping methods. Three S. enterica isolates had O antigen gene clusters with homology to the Escherichia coli O123 O antigen region. O antigen clusters from two serogroup O58 S. enterica strains had approximately 85 % identity with the E. coli O123 O antigen region over their entire length, suggesting that these Salmonella and E. coli O antigen regions evolved from a common ancestor. The O antigen cluster of a Salmonella serogroup O41 isolate had a lower level of identity with E. coli O123 over only part of its O antigen DNA cluster sequence, suggesting a different and more complex evolution of this gene cluster than those in the O58 strains. A large part of the Salmonella O41 O antigen DNA cluster had very close identity with the O antigen cluster of an O62 strain. This region of DNA homology included the wzx and wzy genes. Therefore, molecular serotyping tests using only the O41 or O62 wzx and wzy genes would not differentiate between the two serogroups. The E. coli O123 O-antigenic polysaccharide and its repeating unit were characterized, and the chemical structure for E. coli O123 was entirely consistent with the O antigen gene cluster sequences of E. coli O123 and the Salmonella O58 isolates. An understanding of both the genetic and structural composition of Salmonella and E. coli O antigens is necessary for the development of novel molecular methods for serotyping these organisms.
Leukocyte populations and cytokine expression in the mammary gland in a mouse model of Streptococcus agalactiae mastitis
Authors: Trigo Gabriela , Dinis Márcia , França Ângela , Bonifácio Andrade Elva , Gil da Costa Rui M. , Ferreira Paula , Tavares Delfina
Published: June 2009

Streptococcus agalactiaeis a contagious, mastitis-causing pathogen that is highly adapted to survive in the bovine mammary gland. This study used a BALB/c mouse model ofStreptococcus agalactiaemastitis to evaluate leukocyte populations in regional lymph nodes and cytokine expression in the mammary gland involved in the immune response againstStreptococcus agalactiae. It was found that the bacteria replicated efficiently in the mammary gland, peaking after 24 h and increasing by 100-fold. Dissemination of bacteria to systemic organs was observed 6 h after infection. At the same time, a massive infiltration of polymorphonuclear cells and an increase in the inflammatory cytokines interleukin (IL)-1β, IL-6 and tumour necrosis factor-αwere detected in mammary glands, indicating an early inflammatory response. A decrease in the levels of inflammatory cytokines in mammary glands was observed 72 h after infection, accompanied by an increase in the levels of IL-12 and IL-10, which were related to a gradual decrease in bacterial load. An increase in the number of macrophages and B220+lymphocytes and similar increases in both CD4+and CD8+T cells in regional lymph nodes were observed, being most pronounced 5 days after infection. Moreover, increased levels of anti-Streptococcus agalactiaeantibodies in the mammary gland were observed 10 days after infection. Overall, these data suggest that the host exhibits both innate and acquired immune responses in response toStreptococcus agalactiaemastitis.
Isolation and detection of Shiga toxin-producing Escherichia coli in clinical stool samples using conventional and molecular methods
Authors: Gilmour Matthew W. , Chui Linda , Chiu Theodore , Tracz Dobryan M. , Hagedorn Kathryn , Tschetter Lorelee , Tabor Helen , Ng Lai King , Louie Marie
Published: June 2009

The isolation of Shiga toxin-producingEscherichia coli(STEC) other than serogroup O157 from clinical stool samples is problematic due to the lack of differential phenotypic characteristics from non-pathogenicE. coli. The development of molecular reagents capable of identifying both toxin and serogroup-specific genetic determinants holds promise for a more comprehensive characterization of stool samples and isolation of STEC strains. In this study, 876 stool samples from paediatric patients with gastroenteritis were screened for STEC using a cytotoxicity assay, commercial immunoassay and a conventional PCR targeting Shiga-toxin determinants. In addition, routine culture methods for isolating O157 STEC were also performed. The screening assays identified 45 stools presumptively containing STEC, and using non-differential culture techniques a total of 20 O157 and 22 non-O157 strains were isolated. These included STEC serotypes O157 : H7, O26 : H11, O121 : H19, O26 : NM, O103 : H2, O111 : NM, O115 : H18, O121 : NM, O145 : NM, O177 : NM and O5 : NM. Notably, multiple STEC serotypes were isolated from two clinical stool samples (yielding O157 : H7 and O26 : H11, or O157 : H7 and O103 : H2 isolates). These data were compared to molecular serogroup profiles determined directly from the stool enrichment cultures using a LUX real-time PCR assay targeting the O157 fimbrial genelpfA, a microsphere suspension array targeting allelic variants ofespZand agnd-based molecular O-antigen serogrouping method. The genetic profile of individual stool cultures indicated that theespZmicrosphere array andlpfAreal-time PCR assay could accurately predict the presence and provide preliminary typing for the STEC strains present in clinical samples. Thegnd-based molecular serogrouping method provided additional corroborative evidence of serogroup identities. This toolbox of molecular methods provided robust detection capabilities for STEC in clinical stool samples, including co-infection of multiple serogroups.
Cutaneous infection caused by Aspergillus terreus
Authors: Ozer Burcin , Kalaci Aydiner , Duran Nizami , Dogramaci Yunus , Yanat Ahmet Nedim
Published: June 2009

Aspergillus species are widely distributed in nature, and more than 30 species have been reported to be involved in human and animal infection. Cutaneous infections due to Aspergillus terreus are particularly rare. In this report, we describe a case of cutaneous infection caused by A. terreus in a paediatric patient who underwent surgical treatment for an open tibial fracture secondary to an agricultural accident.
The cationic peptide magainin II is antimicrobial for Burkholderia cepacia-complex strains
Authors: Thwaite Joanne E. , Humphrey Suzanne , Fox Marc A. , Savage Victoria L. , Laws Thomas R. , Ulaeto David O. , Titball Richard W. , Atkins Helen S.
Published: June 2009

This study was undertaken to determine the antibacterial activity of eight cationic antimicrobial peptides towards strains of genomovars I–V of theBurkholderia cepaciacomplex (Bcc) in time–kill assays. All but one of the peptides failed to show activity against the panel of test strains. The exception was magainin II, a 23 aa peptide isolated from the epidermis of the African clawed frog,Xenopus laevis, which exhibited significant bactericidal activity for Bcc genomovars most frequently associated with lung infection of patients with cystic fibrosis.In vitrostudies indicated that magainin II protected a human bronchial epithelial cell line (BEAS-2B) from killing by Bcc and suggest that this peptide may have therapeutic potential against these organisms.
Isolation of Candida dubliniensis from denture wearers
Authors: Gasparoto Thaís Helena , Dionísio Thiago José , de Oliveira Carine Ervolino , Porto Vinicius Carvalho , Gelani Valéria , Santos Carlos Ferreira , Campanelli Ana Paula , Lara Vanessa Soares
Published: June 2009

Candida albicans is considered the most important Candida species able to cause oral infections in denture wearers. In recent years, Candida dubliniensis has emerged as a pathogenic yeast in humans. The close phenotypic similarities of C. albicans and C. dubliniensis have led to the misidentification of these species. In this work, our aim was to verify through PCR the presence of C. dubliniensis in palate and maxillary denture samples from 112 denture wearers presenting with or without denture-related stomatitis (DRS). C. dubliniensis was isolated at low rates from both palate (5.3 % and 10.7 %) and maxillary denture (5.3 % and 8.9 %) samples from wearers regardless of the presence of the disease. However, when C. dubliniensis was detected in individuals with DRS, it was always associated with C. albicans. In addition, our results showed that C. albicans was the most commonly identified candidal species in maxillary denture and hard palate samples from DRS patients (78.5 % and 89.2 %, respectively) as well as from controls (31.2 % and 28.5 %, respectively). In conclusion, C. dubliniensis was detected in the oral environment of denture wearers. The association of C. dubliniensis with C. albicans occurred in approximately 10 % of the DRS cases.
Characterization of Mycobacterium avium clinical isolates in Japan using subspecies-specific insertion sequences, and identification of a new insertion sequence, ISMav6
Authors: Ichikawa Kazuya , Yagi Tetsuya , Moriyama Makoto , Inagaki Takayuki , Nakagawa Taku , Uchiya Kei-Ichi , Nikai Toshiaki , Ogawa Kenji
Published: June 2009

Clinical isolates ofMycobacterium avium(n=81) from patients with pulmonary infections who were HIV-negative and isolates (n=33) from HIV-positive patients were subjected to genetic analysis by PCR detection of threeM. avium-specific insertion sequences (IS901, IS1245and IS1311), and nucleotide sequencing of the heat-shock protein 65 (hsp65) gene. All clinical isolates were identified as ‘M. aviumsubspecieshominissuis’ by sequence analysis ofhsp65. Compared with clinical isolates ofM. aviumreported elsewhere, IS1245was found less frequently in Japanese isolates (96/114 isolates, 84 %) and IS901was detected more frequently (76/114 isolates, 67 %). One isolate was found to lack IS1311, which has not been reported previously for ‘M. aviumsubsp.hominissuis’. Nucleotide sequence analysis of the PCR products for IS901revealed that all clinical isolates had the same new insertion sequence, designated ISMav6, which had 60 point mutations compared with the nucleotide sequence of the original IS901. These results suggest that ‘M. aviumsubsp.hominissuis’ with ISMav6is prevalent in Japan. ISMav6may have implications for the virulence ofM. aviumand contribute to an increase ofM. aviuminfections in this country.
Toxin A-producing Clostridium difficile as an aetiological factor of post-traumatic wound infection
Authors: Deptuła Aleksander , Kruszyńska Ewa , Mikucka Agnieszka , Gospodarek Eugenia , Olszewski Krzysztof , Kruczyński Jacek , Mątewski Dariusz
Published: June 2009

Clostridium difficile is a well-known cause of hospital-acquired infection such as antibiotic associated diarrhoea or pseudomembranous colitis. Extraintestinal infections caused by this pathogen are described rarely. A case of post-traumatic wound infection caused by C. difficile in an immunocompetent, young and otherwise healthy trauma patient is reported. A 31-year-old female, a car accident victim, was admitted to hospital because of polytrauma. After open reduction and internal fixation of a supracondylar femoral fracture by means of the dynamic condylar screw (DCS) system, a purulent fistula occurred. Microbiological examination of the pus revealed C. difficile as the single aetiological factor of this infection. Empirical antibiotic treatment with cefazoline and metronidazole had been administered right after the surgery, but was found to be ineffective. The strain isolated from the patient was sensitive to most antimicrobials except for clindamycin, and amoxicillin/clavulanic acid was chosen for the guided therapy. Such treatment combined with the removal of the DCS system produced a desirable effect.
Fatal Morganella morganii bacteraemia in a diabetic patient with gas gangrene
Authors: Ghosh Sujoy , Bal Abhijit M. , Malik Iqbal , Collier Andrew
Published: June 2009

We report a case of a 60-year-old lady with a history of a heel ulcer that had not responded to antibiotic therapy. This progressed to involve the right leg, which was swollen and erythematous. Radiological imaging revealed the presence of gas within the fascial planes. Blood cultures on admission yielded Morganella morganii. Due to the extent of the gas gangrene and her co-morbidities the patient was not suitable for surgical intervention and was treated conservatively with antibiotics. She deteriorated and died within 72 h of presentation. Non-clostridial gas gangrene is relatively rare, and diagnosis is frequently delayed and often missed. Early aggressive surgical intervention combined with appropriate antibiotic therapy is essential. Bacterial species other than Clostridium should be considered in all cases of gas gangrene.
Tissue microarray and immunohistochemistry as tools for evaluation of antibodies against Chlamydia-like bacteria
Authors: Borel Nicole , Casson Nicola , Entenza José M. , Kaiser Carmen , Pospischil Andreas , Greub Gilbert
Published: June 2009

Tissue microarray technology was used to establish immunohistochemistry protocols and to determine the specificity of new antisera against various Chlamydia-like bacteria for future use on formalin-fixed and paraffin-embedded tissues. The antisera exhibited strong reactivity against autologous antigen and closely related heterologous antigen, but no cross-reactivity with distantly related species.
Biofilm characteristics of Staphylococcus epidermidis isolates associated with device-related meningitis
Authors: Stevens Niall T. , Greene Catherine M. , O'Gara James P. , Humphreys Hilary
Published: June 2009

Staphylococcus epidermidis biofilm causes device-related meningitis in neurosurgical patients. This study assessed the contribution of polysaccharide and protein to the development of a strong biofilm-positive phenotype in four S. epidermidis isolates associated with probable device-related meningitis, under varying environmental conditions. RT-PCR analysis of the intercellular adhesion operon (icaADBC) and assessment of polysaccharide intercellular adhesin (PIA) production indicated a correlation between increased icaA transcription and PIA production in ica
+ isolates grown in medium with 4 % ethanol and 4 % NaCl. Treatment of biofilm with sodium metaperiodate caused dispersion of adhered cells (P <0.0001), indicating involvement of PIA. Transcriptional levels of protein factors revealed that atlE transcription levels were similar in all isolates, whilst aap levels were variable, with induction being seen in two isolates following growth in the presence of alcohol or salt. Transcription of agr did not influence protein expression and RNAIII transcription varied among the strains. Although aap transcription was induced, the treatment of biofilm with proteinase K did not always disperse the biofilm. Our data suggest that, among the three ica
+
S. epidermidis isolates clinically associated with meningitis that were studied, PIA contributed to the strong biofilm-positive phenotype, whereas protein factors appeared to have a secondary role.
Novel synergistic antibiofilm combinations for salvage of infected catheters
Authors: Venkatesh Mohan , Rong Liang , Raad Issam , Versalovic James
Published: June 2009

Biofilms on catheters are responsible for catheter-related bloodstream infections (CRBSIs), which cause significant mortality and morbidity. Antimicrobial catheter-lock solutions may salvage precious catheters by eradicating biofilms. Staphylococcus epidermidis and Candida albicans are frequently isolated organisms in CRBSIs. We evaluated N-acetylcysteine (NAC), EDTA, ethanol and talactoferrin (TLF) individually and in combination with antibiotics against biofilms of S. epidermidis and C. albicans to identify effective catheter-lock solutions. Minimum biofilm-eradication concentrations causing 50 % inhibition (MBEC50) for EDTA, NAC, ethanol and TLF were determined against biofilms of S. epidermidis and C. albicans formed on 96-well microtitre plates. Biomass, mean thickness and viability of S. epidermidis and C. albicans biofilms were evaluated after exposure to MBEC50 concentrations of EDTA, NAC, ethanol and TLF. Antimicrobial combinations of EDTA, NAC, ethanol and TLF with nafcillin, vancomycin, fluconazole and amphotericin B were evaluated systematically for synergy using combination indices (CIs). EDTA, NAC, ethanol and TLF significantly reduced biofilm biomass and mean thickness (P<0.05, one-way ANOVA) of monomicrobial and polymicrobial biofilms as evaluated by confocal microscopy. CIs evaluated at equipotency ratios, and 50, 75 and 90 % effects, showed that EDTA, NAC, ethanol and TLF were synergistic (CI <1) with antibiotics (with few exceptions) against biofilms of S. epidermidis and C. albicans. EDTA, NAC, ethanol and TLF inhibit monomicrobial and polymicrobial biofilms of neonatal strains of S. epidermidis and C. albicans, and are synergistic with antibiotics. Catheter-lock solutions of EDTA, NAC and ethanol alone or in combination with antibiotics may be used to salvage infected catheters, which will directly impact on patient morbidity and health-care costs.
Evaluation of new selective culture media and a rapid fluorescence in situ hybridization assay for identification of Clostridium difficile from stool samples
Authors: Bloedt Kathrin , Riecker Melanie , Poppert Sven , Wellinghausen Nele
Published: June 2009

Two newClostridium difficile-selective agars, from Oxoid (according to Brazier) and from BD, were compared with cycloserine-cefoxitin-fructose agar (Oxoid) for their sensitivity of recovery of toxigenicC. difficilefrom stool samples. For the culture-positive samples, the sensitivities were 84.0, 42.6 and 90.4 %, respectively. In addition, aC. difficile-specific fluorescencein situhybridization assay was developed, facilitating rapid and reliable identification of cultured isolates.
Comparative evaluation of published cytomegalovirus primers for rapid real-time PCR: which are the most sensitive?
Authors: Habbal Wafa , Monem Fawza , Gärtner Barbara C.
Published: June 2009

Standardization of human cytomegalovirus (CMV) PCR is highly recommended. As primer design is essential for PCR sensitivity, this study evaluated all published CMV primer pairs to identify the most sensitive for single-round real-time PCR. PubMed (1993–2004) was searched for original papers aimed at CMV PCR. Fifty-seven papers were identified revealing 82 different primer pairs. Of these, 17 primer sets were selected for empirical study, as they were either used in real-time PCR or were evaluated comparatively by conventional PCR. After optimizing the PCR conditions, these primer sets were evaluated by real-time PCR using a SYBR Green format. Analytical sensitivities were assessed by testing the reference standard CMV strain AD169. Ablastsearch was performed to identify mismatches with published sequences. Additionally, 60 clinical samples were tested with the three primer sets showing highest analytical sensitivity and the best match to all CMV strains. Three primer sets located in the glycoprotein B (UL55) gene region were found to be the most sensitive using strain AD169. However, two of these showed a considerable number of mismatches with clinical isolates in ablastsearch. Instead, two other pairs from the lower matrix phosphoprotein (UL83) gene and DNA polymerase (UL54) gene showed reasonable sensitivity and no mismatches with clinical isolates. These three pairs were further tested with clinical samples, which indicated that the two primer sets fromUL55andUL54were the most sensitive. Interestingly, the analytical sensitivity of the PCR was inversely correlated with the size of the PCR product. In conclusion, these two primer pairs are recommended for a standardized, highly sensitive, real-time PCR.
Histone H2A.Z is essential for estrogen receptor signaling
Authors: Gévry Nicolas , Hardy Sara , Jacques Pierre-Étienne , Laflamme Liette , Svotelis Amy , Robert François , Gaudreau Luc
Published: June 2009

Incorporation of H2A.Z into the chromatin of inactive promoters has been shown to poise genes for their expression. Here we provide strong evidence that H2A.Z is incorporated into the promoter regions of estrogen receptor (ERα) target genes only upon gene induction, and that, in a cyclic pattern. Moreover, members of the human H2A.Z-depositing complex, p400, also follow the same gene recruitment kinetics as H2A.Z. Importantly, cellular depletion of H2A.Z or p400 leads to a severe defect in estrogen signaling, including loss of estrogen-specific cell proliferation. We find that incorporation of H2A.Z within TFF1 promoter chromatin allows nucleosomes to adopt preferential positions along the DNA translational axis. Finally, we provide evidence that H2A.Z is essential to allow estrogen-responsive enhancer function. Taken together, our results provide strong mechanistic insight into how H2A.Z regulates ERα-mediated gene expression and provide a novel link between H2A.Z–p400 and ERα-dependent gene regulation and enhancer function.
Dysregulation of the Wnt pathway inhibits timely myelination and remyelination in the mammalian CNS
Authors: Fancy Stephen P.J. , Baranzini Sergio E. , Zhao Chao , Yuk Dong-In , Irvine Karen-Amanda , Kaing Sovann , Sanai Nader , Franklin Robin J.M. , Rowitch David H.
Published: June 2009

The progressive loss of CNS myelin in patients with multiple sclerosis (MS) has been proposed to result from the combined effects of damage to oligodendrocytes and failure of remyelination. A common feature of demyelinated lesions is the presence of oligodendrocyte precursors (OLPs) blocked at a premyelinating stage. However, the mechanistic basis for inhibition of myelin repair is incompletely understood. To identify novel regulators of OLP differentiation, potentially dysregulated during repair, we performed a genome-wide screen of 1040 transcription factor-encoding genes expressed in remyelinating rodent lesions. We report that ∼50 transcription factor-encoding genes show dynamic expression during repair and that expression of the Wnt pathway mediator Tcf4 (aka Tcf7l2) within OLPs is specific to lesioned—but not normal—adult white matter. We report that β-catenin signaling is active during oligodendrocyte development and remyelination in vivo. Moreover, we observed similar regulation of Tcf4 in the developing human CNS and lesions of MS. Data mining revealed elevated levels of Wnt pathway mRNA transcripts and proteins within MS lesions, indicating activation of the pathway in this pathological context. We show that dysregulation of Wnt–β-catenin signaling in OLPs results in profound delay of both developmental myelination and remyelination, based on (1) conditional activation of β-catenin in the oligodendrocyte lineage in vivo and (2) findings from APCMin mice, which lack one functional copy of the endogenous Wnt pathway inhibitor APC. Together, our findings indicate that dysregulated Wnt–β-catenin signaling inhibits myelination/remyelination in the mammalian CNS. Evidence of Wnt pathway activity in human MS lesions suggests that its dysregulation might contribute to inefficient myelin repair in human neurological disorders.
Ephrin-B1 regulates axon guidance by reverse signaling through a PDZ-dependent mechanism
Authors: Bush Jeffrey O. , Soriano Philippe
Published: June 2009

Mutations in the ephrin-B1 gene result in craniofrontonasal syndrome (CFNS) in humans, a congenital disorder that includes a wide range of craniofacial, skeletal, and neurological malformations. In addition to the ability of ephrin-B1 to forward signal through its cognate EphB tyrosine kinase receptors, ephrin-B1 can also act as a receptor and transduce a reverse signal by either PDZ-dependent or phosphorylation-dependent mechanisms. To investigate how ephrin-B1 acts to influence development and congenital disease, we generated mice harboring a series of targeted point mutations in the ephrin-B1 gene that independently ablate specific reverse signaling pathways, while maintaining forward signaling capacity. We demonstrate that both PDZ and phosphorylation-dependent reverse signaling by ephrin-B1 are dispensable for craniofacial and skeletal development, whereas PDZ-dependent reverse signaling by ephrin-B1 is critical for the formation of a major commissural axon tract, the corpus callosum. Ephrin-B1 is strongly expressed within axons of the corpus callosum, and reverse signaling acts autonomously in cortical axons to mediate an avoidance response to its signaling partner EphB2. These results demonstrate the importance of PDZ-dependent reverse signaling for a subset of Ephrin-B1 developmental roles in vivo.
Stalled Hox promoters as chromosomal boundaries
Authors: Chopra Vivek S. , Cande Jessica , Hong Joung-Woo , Levine Michael
Published: June 2009

Many developmental control genes contain stalled RNA Polymerase II (Pol II) in the early Drosophila embryo, including four of the eight Hox genes. Here, we present evidence that the stalled Hox promoters possess an intrinsic insulator activity. The enhancer-blocking activities of these promoters are dependent on general transcription factors that inhibit Pol II elongation, including components of the DSIF and NELF complexes. The activities of conventional insulators are also impaired in embryos containing reduced levels of DSIF and NELF. Thus, promoter-proximal stalling factors might help promote insulator–promoter interactions. We propose that stalled promoters help organize gene complexes within chromosomal loop domains.
Egalitarian is a selective RNA-binding protein linking mRNA localization signals to the dynein motor
Authors: Dienstbier Martin , Boehl Florian , Li Xuan , Bullock Simon L.
Published: June 2009

Cytoplasmic sorting of mRNAs by microtubule-based transport is widespread, yet very little is known at the molecular level about how specific transcripts are linked to motor complexes. InDrosophila, minus-end-directed transport of developmentally important transcripts by the dynein motor is mediated by seemingly divergent mRNA elements. Here we provide evidence that direct recognition of these mRNA localization signals is mediated by the Egalitarian (Egl) protein. Egl and the dynein cofactor Bicaudal-D (BicD) are the only proteins from embryonic extracts that are abundantly and specifically enriched on RNA localization signals from transcripts ofgurken,hairy,K10, and theI factorretrotransposon. In vitro assays show that, despite lacking a canonical RNA-binding motif, Egl directly recognizes active localization elements. We also reveal a physical interaction between Egl and a conserved domain for cargo recruitment in BicD and present data suggesting that Egl participates selectively in BicD-mediated transport of mRNA in vivo. Our work leads to the first working model for a complete connection between minus-end-directed mRNA localization signals and microtubules and reveals molecular strategies that are likely to be of general relevance for cargo transport by dynein.
Clinical trial: lansoprazole 15 or 30 mg once daily vs. placebo for treatment of frequent nighttime heartburn in self‐treating subjects
Authors: PEURA D. A. , RIFF D. S. , SNODDY A. M. , FENNERTY M. B.
Published: June 2009

Background Frequent nighttime heartburn is common. Lansoprazole 15 mg is indicated for treatment of heartburn and other gastro‐oesophageal reflux disease‐related symptoms.

Aim To evaluate the efficacy and safety of lansoprazole in self‐treating subjects with frequent nocturnal heartburn.

Methods A total of 864 subjects with heartburn on ≥2 days/week over the past month were randomized to double‐blind treatment with lansoprazole 15 or 30 mg or placebo each morning. Endpoints were percentage of nighttimes without heartburn (primary), percentage of 24‐h days without heartburn and percentage of subjects without heartburn on day 1.

Results Mean percentage of nighttimes without heartburn was significantly greater with lansoprazole 15 mg (61.3%) or lansoprazole 30 mg (61.7%) vs. placebo (47.8%) over 14 days (P < 0.0001 vs. placebo for both doses). Percentage of 24‐h days without heartburn and percentage of subjects without heartburn on day 1 were significantly greater with lansoprazole 15 or 30 mg vs. placebo.

Conclusions Both lansoprazole 15 and 30 mg were highly effective and well tolerated in reducing symptoms in subjects with frequent nighttime heartburn. The benefit of therapy on 24‐h heartburn and nighttime heartburn on day 1 of treatment was also evident. Lansoprazole 15 mg is a suitable choice for management of frequent nighttime heartburn.
Impact of ribavirin plasma level on sustained virological response in patients treated with pegylated interferon and ribavirin for chronic hepatitis C
Authors: BREILH D. , FOUCHER J. , CASTÉRA L. , TRIMOULET P. , DJABAROUTI S. , MERROUCHE W. , COUZIGOU P. , SAUX M.‐C. , DE LÉDINGHEN V.
Published: June 2009

Background  The main goal of therapy in hepatitis C virus (HCV) infection is to achieve a sustained virological response (SVR). However, the impact of the pharmacological properties of ribavirin on the SVR has not been fully investigated.

Aim  To evaluate, through a prospective study, the association between ribavirin plasma level and SVR response in HCV patients treated with pegylated interferon (PEG‐IFN) and ribavirin.

Patients and methods  Patients treated with PEG‐IFN and ribavirin had plasmatic ribavirin dosage at weeks 4 and 12. SVR was evaluated 6 months after the end of treatment.

Results  At week 4, a strong correlation was found between HCV‐RNA and Cmin of ribavirin plasma level (r = −0.376, P = 0.002) and AUC0→12h of ribavirin plasma level (r = −0.277, P = 0.018). At week 12, a strong correlation was found between HCV‐RNA and Cmin of ribavirin plasma level (r = −0.384, P < 0.0001) and AUC0→12h of ribavirin plasma level (r = −0.257, P = 0.002). In genotype 1 patients, AUC0→12h ribavirin and Cmin were significantly correlated with negative HCV‐RNA at week 12 and SVR. In the multiple logistic regression model, the only factor independently associated with SVR in genotype 1 patients was negative HCV‐RNA at week 12.

Conclusion  Cmin of ribavirin at weeks 4 and 12 was significantly higher in sustained virological responders compared with relapser or nonresponder patients. However, in genotype 1 patients, plasma ribavirin level at weeks 4 and 2 was not associated with SVR.