bluuebunny/crossref_metadata_2025 huggingface dataset:
Pharmacological investigation of the bioluminescence signaling pathway of the dinoflagellate Lingulodinium polyedrum: evidence for the role of stretch‐activated ion channels
Authors: Jin Kelly , Klima Jason C. , Deane Grant , Dale Stokes Malcolm , Latz Michael I.
Published: May 2013

Dinoflagellate bioluminescence serves as a whole‐cell reporter of mechanical stress, which activates a signaling pathway that appears to involve the opening of voltage‐sensitive ion channels and release of calcium from intracellular stores. However, little else is known about the initial signaling events that facilitate the transduction of mechanical stimuli. In the present study using the red tide dinoflagellate Lingulodinium polyedrum (Stein) Dodge, two forms of dinoflagellate bioluminescence, mechanically stimulated and spontaneous flashes, were used as reporter systems to pharmacological treatments that targeted various predicted signaling events at the plasma membrane level of the signaling pathway. Pretreatment with 200 μM Gadolinium III (Gd3+), a nonspecific blocker of stretch‐activated and some voltage‐gated ion channels, resulted in strong inhibition of both forms of bioluminescence. Pretreatment with 50 μM nifedipine, an inhibitor of L‐type voltage‐gated Ca2+ channels that inhibits mechanically stimulated bioluminescence, did not inhibit spontaneous bioluminescence. Treatment with 1 mM benzyl alcohol, a membrane fluidizer, was very effective in stimulating bioluminescence. Benzyl alcohol‐stimulated bioluminescence was inhibited by Gd3+ but not by nifedipine, suggesting that its role is through stretch activation via a change in plasma membrane fluidity. These results are consistent with the presence of stretch‐activated and voltage‐gated ion channels in the bioluminescence mechanotransduction signaling pathway, with spontaneous flashing associated with a stretch‐activated component at the plasma membrane.
Expression patterns of tight junction components induced by CD24 in an oral epithelial cell‐culture model correlated to affected periodontal tissues
Authors: Ye P. , Yu H. , Simonian M. , Hunter N.
Published: May 2013

Background and Objective

Previously we demonstrated uniformly strong expression of CD24 in the epithelial attachment to the tooth and in the migrating epithelium of the periodontitis lesion. Titers of serum antibodies autoreactive with CD24 peptide correlated with reduced severity of periodontal disease. Ligation of CD24 expressed by oral epithelial cells induced formation of tight junctions that limited paracellular diffusion. In this study, we aimed to reveal that the lack of uniform expression of tight junction components in the pocket epithelium of periodontitis lesions is likely to contribute to increased paracellular permeability to bacterial products. This is proposed as a potential driver of the immunopathology of periodontitis.

Material and Methods

An epithelial culture model with close correspondence for expression patterns for tight junction components in periodontal epithelia was used. Immunohistochemical staining and confocal laser scanning microscopy were used to analyse patterns of expression of gingival epithelial tight junction components.

Results

The minimally inflamed gingival attachment was characterized by uniformly strong staining at cell contacts for the tight junction components zona occludens‐1, zona occludens‐2, occludin, junction adhesion molecule‐A, claudin‐4 and claudin‐15. In contrast, the pocket epithelium of the periodontal lesion showed scattered, uneven staining for these components. This pattern correlated closely with that of unstimulated oral epithelial cells in culture. Following ligation of CD24 expressed by these cells, the pattern of tight junction component expression of the minimally inflamed gingival attachment developed rapidly.

Conclusion

There was evidence for non‐uniform and focal expression only of tight junction components in the pocket epithelium. In the cell‐culture model, ligation of CD24 induced a tight junction expression profile equivalent to that observed for the minimally inflamed gingival attachment. Ligation of CD24 expressed by gingival epithelial cells by lectin‐like receptors of commensal oral streptococci could mediate the phenotype of health, whereas pathogenic organisms associated with periodontal disease might not signal effectively through CD24.
Animal Health Modeling & Simulation Society: a new society promoting model‐based approaches in veterinary pharmacology
Authors: Mochel J. P. , Gabrielsson J. , Collard W. , Fink M. , Gehring R. , Laffont C. , Liu Y. , Martin‐Jimenez T. , Pelligand L. , Steimer J.‐L. , Toutain P.‐L. , Whittem T. , Riviere J.
Published: May 2013

The Animal Health Modeling & Simulation Society (AHM&S) is a newly founded association (2012) that aims to promote the development, application, and dissemination of modeling and simulation techniques in the field of Veterinary Pharmacology and Toxicology. The association is co‐chaired by Pr. Johan Gabrielsson (Europe), Pr. Jim Riviere (USA), and secretary Dr. Jonathan Mochel (Switzerland). This short communication aims at presenting the membership, rationale and objectives of this group.
The consequences of generic marketing on antibiotic consumption and the spread of microbial resistance: the need for new antibiotics
Authors: Toutain P.‐L. , Bousquet‐Melou A.
Published: May 2013

In both human and veterinary medicine, it has been shown that flooding the market with different generics and/or ‘me‐too’ branded drugs has increased overall antibiotic consumption correlating with the emergence and spread of bacterial resistance to antibiotics. Another possible undesirable consequence of the promotion of generics is the promotion of an economic incentive that encourages the use of old drug products with very poor oral bioavailability, marketed with historical dosage regimens and extensively excreted in the environment. What veterinary medicine rather needs is new innovative and ‘ecofriendly’ antibiotics to actually enforce a more prudent use of antibiotics. For a pharmaceutical company, generics are inexpensive to manufacture and on a short‐term basis, the generic market is very appealing. However, on a long‐term basis, this marketing orientation provides a disincentive to the development of new and innovative products that will be required to meet the therapeutic needs of the veterinary community while being consistent with public health concerns. Indeed, for veterinary medicine, the key issue surrounding antibiotics is public health. It is the opinion of the authors that veterinary antibiotics and/or veterinary drug formulations should be innovative in terms of selectivity (no or minimal impact on the commensal gut flora), biodegradable (with minimal environmental disruption), and more expensive, with a strictly regulated market rather than unselective, cheap, and freely available drugs.
Acute inactivation of the Aspergillus nidulans Golgi membrane fusion machinery: correlation of apical extension arrest and tip swelling with cisternal disorganization
Authors: Pinar Mario , Pantazopoulou Areti , Arst Herbert N. , Peñalva Miguel A.
Published: May 2013

The mechanisms governing traffic across the Golgi are incompletely understood. We studied, by live‐cell microscopy, the consequences of disorganizing the Aspergillus nidulans Golgi, using an extended set of fluorescent protein markers to resolve early from late cisternae. The early Golgi syntaxin SedVSed5 and the RabORab1 regulatory GTPase play essential roles in secretion, cooperating in the ER–Golgi interface. Following a temperature shift‐up ‘on‐the‐stage’, hyphae carrying engineered sedVR258G and rabOA136D ts mutations arrest polarized growth. This arrest correlates with overall Golgi disorganization and characteristic hyphal tip swelling. Using v‐SNARE SynA as reporter, we show that the sedVR258G phenotypes correlate with arrested secretion. Both the morphogenetic defect and the secretory deficit are reversible. Thus downregulation of secretion, like that of endocytosis, has morphogenetic consequences, implying that mechanisms tuning the secretory pathway might be involved in developmental processes. According to the cisternal maturation model, acute impairment of traffic in the ER–Golgi interface should lead to disorganization of both the early and the late Golgi cisternae. Thus, the relatively rapid late Golgi disorganization observed upon shifting ER–Golgi interface mutants to the restrictive temperature seems incompatible with an A. nidulans Golgi network organized on the basis of stable early and late compartments, supporting instead cisternal maturation.
Bypassing the need for subcellular localization of a polysaccharide export‐anchor complex by overexpressing its protein subunits
Authors: Javens June , Wan Zhe , Hardy Gail G. , Brun Yves V.
Published: May 2013

Subcellular protein localization is thought to promote protein–protein interaction by increasing the effective concentration and enabling spatial co‐ordination and proper segregation of proteins. We found that protein overexpression allowed the assembly of a productive polysaccharide biosynthesis‐export‐anchoring complex in the absence of polar localization in Caulobacter crescentus. Polar localization of the holdfast export protein, HfsD, depends on the presence of the other export proteins, HfsA and HfsB, and on the polar scaffold protein PodJ. The holdfast deficiency of hfsB and podJ mutants is suppressed by the overexpression of export proteins. Restored holdfasts are randomly positioned and colocalize with a holdfast anchor protein in these strains, indicating that functional complexes can form at non‐polar sites. Therefore, overexpression of export proteins surpasses a concentration threshold necessary for holdfast synthesis. Restoration of holdfast synthesis at non‐polar sites reduces surface adhesion, consistent with the need to spatially co‐ordinate the holdfast synthesis machinery with the flagellum and pili. These strains lack the cell‐specific segregation of the holdfast, resulting in the presence of holdfasts in motile daughter cells. Our results highlight the fact that multiple facets of subcellular localization can be coupled to improve the phenotypic outcome of a protein assembly.
Long‐term social structure of a resident community of Atlantic spotted dolphins, Stenella Frontalis, in the Bahamas 1991–2002
Authors: Elliser Cindy R. , Herzing Denise L.
Published: May 2013

Long‐term social structure data on small delphinids is lacking for most species except the bottlenose dolphin. This study describes the long‐term social structure of one community of Atlantic spotted dolphins, Stenella frontalis, divided into three social clusters. Data from 12 yr were analyzed using SOCPROG 2.3. Coefficients of association (CoA) were calculated using the half‐weight index. The overall mean community CoA ranged from 0.09 to 0.12. Temporal analyses and mantel tests revealed significant differences between sex class associations due to high male‐male CoA (0.12–0.23) compared to female‐female and mixed sex CoA (0.08–0.10). Female associations were strongly influenced by reproductive status, calf care, and social familiarity, but not by age class. Male associations were strongly influenced by age, access to females, and alliance formation. Males showed two levels of alliance formation, long‐term first order pairs/trios (CoA 0.70–1.00) and shorter‐term second order alliances between two or more first order alliances (CoA 0.45–0.69), and a possible third level during interspecies interactions. Mating strategies, sex, and cluster formation shaped the social structure in this spotted dolphin community. Similar to many bottlenose dolphin studies, long‐term affiliations for spotted dolphins were correlated with age, sex, and reproductive status.
Bridge to Recovery or Permanent System Implantation: An Eight‐Year Single‐Center Experience in Transvenous Semipermanent Pacing
Authors: KORNBERGER ANGELA , SCHMID ECKHARD , KALENDER GUENAY , STOCK ULRICH ALFRED , DOERNBERGER VOLKER , KHALIL MAHMUD , LISY MILAN
Published: May 2013

Background

To compare the risks, implications, and outcomes of transvenous semipermanent pacing as a bridge to permanent system implantation or recovery.

Methods

We investigated semipermanent transvenous pacing systems consisting of one (n = 57%) or two (n = 3%) bipolar active‐fixation pacing leads and an attached epicutaneous pulse generator implanted from 2000 to 2009. The study population comprised 60 patients aged 72.9 ± 10.5 years (44 [73.3%] male). Forty‐two (70%) were enrolled for complete system explantation for cardiac‐implanted electronic devices associated infection. Eighteen (30%) required temporary pacing in the context of a variety of mostly severe cardiac and noncardiac conditions. The semipermanent pacing systems were removed after implantation of permanent systems or recovery of a noncompromising heart rhythm, respectively.

Results

Transvenous semipermanent lead implantation was successful in 59 (98.3%) patients. Major and minor intraoperative complications occurred in one case (1.7%) each. The semipermanent systems were left in situ for a mean period of 14.6 ± 8.1 days). They served as a bridge to permanent system implantation in 68.3% (n = 41) and as a bridge to recovery of a noncompromising heart rhythm in 11.7% (n = 7). Four patients (8.3%) died with the semipermanent pacing system in situ, and seven (11.7%) were transferred to external hospitals with semipermanent pacing systems.

Conclusions

Transvenous semipermanent pacing with bipolar active‐fixation leads and epicutaneous pulse generators provide an important option for prolonged temporary pacing as a bridge to permanent system implantation or recovery.
ECONOMIC RATIONALES, LEARNING, AND REGULATORY POLICY INSTRUMENTS
Authors: COLETTI PAOLA , RADAELLI CLAUDIO M.
Published: May 2013

European governments have adopted policy instruments for regulatory appraisal, oversight, ex‐post evaluation, and simplification in the context of the so‐called ‘smart regulation agenda’. In this article we compare the two most important instruments, that is, regulatory impact assessment (RIA) and the standard cost model (SCM). We answer the following questions: What are the economic rationales that, at least in principle, should make the SCM and RIA work? What are the learning models that, yet again in principle, allow the two instruments to produce effects? The RIA economic rationale is grounded in welfare economics. The SCM economics is rudimentary: one can hardly make an economic case for the SCM. With regard to learning models, RIA draws on rational‐synoptic models, whilst the SCM is inspired by experience‐based learning. We then discuss economic rationales and learning models jointly, thus explaining the different implementation patterns of the two instruments and exposing the ambiguities in the relationship among instruments, ideas, and behavioural change.
Age‐related activity patterns are moderated by diet in Queensland fruit flies Bactrocera tryoni
Authors: PRENTER JOHN , WELDON CHRISTOPHER W. , TAYLOR PHILLIP W.
Published: May 2013

Life‐history parameters and the fitness of tephritid flies are closely linked to diet. Studies of locomotor behaviour can provide insights to these links, although little is known about how locomotor behaviour is influenced by diet. In the present study, video recordings of Queensland fruit flies Bactrocera tryoni Froggatt (Diptera: Tephritidae) (‘Q‐flies’) that are maintained individually in cages are used to determine how diet affects the activity patterns (flight, walking, grooming, inactivity) of males and females at ages ranging from 4 to 30 days. The frequency and total duration of activities over 10‐min trials are affected by diet, age and sex. Supplementation of diet with hydrolysed yeast results in a higher frequency and duration of flight in flies of all ages and both sexes. The effect of diet on other activities varies with age. Q‐flies fed sugar only increase walking frequency steadily from 4 to 30 days post‐eclosion, whereas flies fed sugar + yeast have higher walking frequencies at 4 and 10 days than flies fed sugar only, although they then exhibit a sharp decline at 30 days post‐eclosion. The frequency and duration of inactivity remain consistent in flies fed sugar + yeast, whereas flies fed sugar only exhibit a marked increase in inactivity from 4 to 30 days post‐eclosion. Compared with older flies, 4 day‐old Q‐flies fed sugar only spend considerably more time grooming. The potential of activity monitoring as a quality control test for flies that are mass‐reared for use in sterile insect technique programmes is discussed.
Marked cardiomegaly in a patient with familial amyloidotic polyneuropathy after orthotopic liver transplantation: a case study
Authors: Sakashita Naomi , Kagawa Seiko , Date Risako , Ueno Tatsuro , Nakagawa Takenobu , Yamashita Taro , Obayashi Konen , Ohshima Toshinori , Ueda Mitsuharu , Horiguchi Hidehisa , Ando Yukio , Takeya Motohiro
Published: May 2013

Hepatocyte‐derived mutant amyloidogenic transthyretin (ATTR) causes familial amyloidotic polyneuropathy (FAP), for which orthotopic liver transplantation is an established curative treatment. However, some patients with FAP have cardiac amyloidosis after transplantation. Here, we describe a man with an autonomic disorder diagnosed as FAP ATTR Val30Met and marked cardiomegaly after liver transplantation. He underwent orthotopic liver transplantation at 49 years of age and was prescribed prednisolone to prevent graft rejection. Two years later, autonomic dysfunction and severe heart failure gradually developed. He died suddenly at 59. The autopsy revealed marked cardiomegaly (heart weight: 1020 g). Histological and ultrastructural examinations demonstrated massive amyloid deposition and unusual myocardial hypertrophic injury associated with nuclear translocation of the glucocorticoid receptor (GR). No other FAP patients without heart failure showed GR nuclear translocation. GR is a nuclear transcription factor that leads to myocardial hypertrophy, and cumulative prednisolone doses may promote marked cardiomegaly and severe cardiac amyloidosis.
Continuous positive airway pressure in clinically stable patients with mild‐to‐moderate obesity hypoventilation syndrome and obstructive sleep apnoea
Authors: Salord Neus , Mayos Mercedes , Miralda Rosa Maria , Farré Ariadna , Carreras Montserrat , Sust Rosa , Masuet‐Aumatell Cristina , Rodríguez Jose , Pérez Antonio
Published: May 2013

Background and objective

The use of continuous positive airway pressure (CPAP) treatment in patients with obesity hypoventilation syndrome (OHS) and obstructive sleep apnoea (OSA) was evaluated, and factors that might predict CPAP treatment failure were determined.

Methods

A sleep study was performed in 29 newly diagnosed, clinically stable OHS patients. CPAP treatment was commenced if the apnoea–hypopnoea index was >15. Lung function, night‐time oximetry, blood adipokine and C‐reactive protein levels were assessed prospectively on enrollment and after 3 months. Treatment failure at 3 months was defined as daytime arterial partial pressure of carbon dioxide (PaCO2) >45 mm Hg and/or oxygen saturation (SpO2) <90% for >30% of the night‐time oximetry study.

Results

All patients had severe OSA (median apnoea–hypopnoea index = 74.7 (62–100) with a nocturnal mean SpO2 of 81.4 ± 7), and all patients were treated with CPAP. The percentage of time spent below 90% saturation improved from 8.4% (0.0–39.0%) to 0.3% (0.4–4.0%). Awake PaCO2 decreased from 50 (47–53) mm Hg to 43 (40–45) mm Hg. Seven patients failed CPAP treatment after 3 months. PaCO2 at 1 month and mean night‐time SpO2 during the first night of optimal CPAP were associated with treatment failure at 3 months (odds ratio 1.4 (1.03–1.98); P = 0.034 and 0.6 (0.34–0.93); P = 0.027).

Conclusions

CPAP treatment improves night‐time oxygenation and daytime hypoventilation in selected clinically stable OHS patients who also have OSA. Patients with worse night‐time saturation while on CPAP and higher daytime PaCO2 at 1 month were more likely to fail CPAP treatment.
On the Treatment of Uncertainty and Variability in Making Decisions About Risk
Authors: Bier Vicki M. , Lin Shi‐Woei
Published: May 2013

Much attention has been paid to the treatment of dependence and to the characterization of uncertainty and variability (including the issue of dependence among inputs) in performing risk assessments to avoid misleading results. However, with relatively little progress in communicating about the effects and implications of dependence, the effort involved in performing relatively sophisticated risk analyses (e.g., two‐dimensional Monte Carlo analyses that separate variability from uncertainty) may be largely wasted, if the implications of those analyses are not clearly understood by decisionmakers. This article emphasizes that epistemic uncertainty can introduce dependence among related risks (e.g., risks to different individuals, or at different facilities), and illustrates the potential importance of such dependence in the context of two important types of decisions—evaluations of risk acceptability for a single technology, and comparisons of the risks for two or more technologies. We also present some preliminary ideas on how to communicate the effects of dependence to decisionmakers in a clear and easily comprehensible manner, and suggest future research directions in this area.
IgA Response to ESAT‐6/CFP‐10 and Rv2031 Antigens Varies in Patients With Culture‐Confirmed Pulmonary Tuberculosis, Healthy Mycobacterium tuberculosis–Infected and Non‐Infected Individuals in a Tuberculosis Endemic Setting, Ethiopia
Authors: Legesse M. , Ameni G. , Medhin G. , Mamo G. , Franken K. L. M. C. , Ottenhoff T. H. M. , Bjune G. , Abebe F.
Published: May 2013

Little attention has been given to the role of antibodies against Mycobacterium tuberculosis (Mtb) infection. We have compared the levels of IgA and IgG against ESAT‐6/CFP‐10 and Rv2031c antigens in sera of patients with culture‐confirmed pulmonary tuberculosis (PTB), healthy Mtb‐infected and non‐infected individuals in endemic TB settings. Venous blood samples were collected from 166 study participants; sera were separated and assayed by an enzyme‐linked immunosorbent assay (ELISA). QuantiFERON‐TB Gold In‐Tube (QFTGIT) assay was used for the screening of latent TB infection. The mean optical density (OD) values of IgA against ESAT‐6/CFP‐10 and Rv2031 were significantly higher in sera of patients with culture‐confirmed PTB compared with healthy Mtb‐infected and non‐infected individuals (P < 0.001). The mean OD values of IgG against ESAT‐6/CFP‐10 and Rv2031 were also significantly higher in sera of patients with culture‐confirmed PTB compared with healthy Mtb‐infected and non‐infected individuals (P < 0.05). The mean OD values of IgA against both antigens were also higher in sera of healthy Mtb‐infected cases compared with non‐infected individuals. There were positive correlations (P < 0.05) between the level of IFN‐γ induced in QFTGIT assay and the OD values of serum IgA against both antigens in healthy Mtb‐infected subjects. This study shows the potential of IgA response against ESAT‐6/CFP‐10 and Rv2031 antigens in discriminating clinical TB from healthy Mtb‐infected and non‐infected cases. Nevertheless, further well‐designed cohort study is needed to fully realize the full potential of this diagnostic marker.
Adenosine Promotes Tumor Metastasis
Authors: Linden Joel
Published: May 2013

Adenosine-mediated signaling suppresses the ability of the small GTPase Rap1B to promote cell-cell adhesion.
Science Signaling
Podcast: 28 May 2013
Authors: Balk Steven P. , VanHook Annalisa M.
Published: May 2013

The tyrosine kinase BMX may act as a global promoter of maximal receptor tyrosine kinase activity.
Obstructing the Craving
Authors: Ferrarelli Leslie K.
Published: May 2013

A neuroprotective drug may treat cocaine addiction and prevent cocaine-induced neurotoxicity by inhibiting the nitrosylation of GAPDH.
A Preclinical Xenograft Model Identifies Castration-Tolerant Cancer-Repopulating Cells in Localized Prostate Tumors
Authors: Toivanen Roxanne , Frydenberg Mark , Murphy Declan , Pedersen John , Ryan Andrew , Pook David , Berman David M. ,   Australian Prostate Cancer BioResource, Taylor Renea A. , Risbridger Gail P.
Published: May 2013

This study uses a preclinical xenograft model to reveal prostate cancer cells that exist in untreated localized disease, survive androgen withdrawal, and are potential therapeutic targets.
A New ABC Half-Transporter in Leishmania major Is Involved in Resistance to Antimony
Authors: Manzano J. I. , García-Hernández R. , Castanys S. , Gamarro F.
Published: May 2013

The characterization of ABCI4, a new intracellular ATP-binding cassette (ABC) half-transporter in
Leishmania major
, is described. We show that ABCI4 is involved in heavy metal export, thereby conferring resistance to Pentostam, to Sb(III), and to As(III) and Cd(II). Parasites overexpressing ABCI4 showed a lower mitochondrial toxic effect of antimony by decreasing reactive oxygen species production and maintained higher values of both the mitochondrial electrochemical potential and total ATP levels with respect to controls. The ABCI4 half-transporter forms homodimers as determined by a coimmunoprecipitation assay. A combination of subcellular localization studies under a confocal microscope and a surface biotinylation assay using parasites expressing green fluorescent protein- and FLAG-tagged ABCI4 suggests that the transporter presents a dual localization in both mitochondria and the plasma membrane. Parasites overexpressing ABCI4 present an increased replication in mouse peritoneal macrophages. We have determined that porphyrins are substrates for ABCI4. Consequently, the overexpression of ABCI4 confers resistance to some toxic porphyrins, such as zinc-protoporphyrin, due to the lower accumulation resulting from a significant efflux, as determined using the fluorescent zinc-mesoporphyrin, a validated heme analog. In addition, ABCI4 has a significant ability to efflux thiol after Sb(III) incubation, thus meaning that ABCI4 could be considered to be a potential thiol-X-pump that is able to recognize metal-conjugated thiols. In summary, we have shown that this new ABC transporter is involved in drug sensitivity to antimony and other compounds by efflux as conjugated thiol complexes.
Compensation of the Metabolic Costs of Antibiotic Resistance by Physiological Adaptation in Escherichia coli
Authors: Händel Nadine , Schuurmans J. Merijn , Brul Stanley , ter Kuile Benno H.
Published: May 2013

Antibiotic resistance is often associated with metabolic costs. To investigate the metabolic consequences of antibiotic resistance, the genomic and transcriptomic profiles of an amoxicillin-resistant
Escherichia coli
strain and the wild type it was derived from were compared. A total of 125 amino acid substitutions and 7 mutations that were located <1,000 bp upstream of differentially expressed genes were found in resistant cells. However, broad induction and suppression of genes were observed when comparing the expression profiles of resistant and wild-type cells. Expression of genes involved in cell wall maintenance, DNA metabolic processes, cellular stress response, and respiration was most affected in resistant cells regardless of the absence or presence of amoxicillin. The SOS response was downregulated in resistant cells. The physiological effect of the acquisition of amoxicillin resistance in cells grown in chemostat cultures consisted of an initial increase in glucose consumption that was followed by an adaptation process. Furthermore, no difference in maintenance energy was observed between resistant and sensitive cells. In accordance with the transcriptomic profile, exposure of resistant cells to amoxicillin resulted in reduced salt and pH tolerance. Taken together, the results demonstrate that the acquisition of antibiotic resistance in
E. coli
is accompanied by specifically reorganized metabolic networks in order to circumvent metabolic costs. The overall effect of the acquisition of resistance consists not so much of an extra energy requirement, but more a reduced ecological range.
Single-Dose Pharmacodynamics of Amphotericin B against Aspergillus Species in an
In Vitro
Pharmacokinetic/Pharmacodynamic Model
Authors: Al-Saigh Rafal , Siopi Maria , Siafakas Nikolaos , Velegraki Aristea , Zerva Loukia , Meletiadis Joseph
Published: May 2013

Conventional MIC testing of amphotericin B results in narrow MIC ranges challenging the detection of resistant strains. In order to discern amphotericin B pharmacodynamics, the
in vitro
activity of amphotericin B was studied against
Aspergillus
isolates with the same MICs by using a new
in vitro
pharmacokinetic/pharmacodynamic (PK/PD) model that simulates amphotericin B human plasma levels. Clinical isolates of
Aspergillus fumigatus
,
A. terreus
, and
A. flavus
with the same Clinical and Laboratory Standards Institute modal MICs of 1 mg/liter were exposed to amphotericin B concentrations following the plasma concentration-time profile after single-bolus administration with
C
max
values of 0.6, 1.2, 2.4, and 4.8 mg/liter. Fungal growth was monitored for up to 72 h based on galactomannan production. Complete growth inhibition was observed only against
A. fumigatus
with amphotericin B with a
C
max
of ≥2.4 mg/liter. At the lower
C
max
values 0.6 and 1.2 mg/liter, significant growth delays of 34 and 52 h were observed, respectively (
P
< 0.001). For
A. flavus
, there was no complete inhibition but a progressive growth delay of 1 to 50 h at an amphotericin B
C
max
of 0.6 to 4.8 mg/liter (
P
< 0.001). For
A. terreus
, the growth delay was modest (up to 8 h) at all
C
max
s (
P
< 0.05). The
C
max
(95% confidence interval) associated with 50% activity for
A. fumigatus
was 0.60 (0.49 to 0.72) mg/liter, which was significantly lower than for
A. flavus
3.06 (2.46 to 3.80) mg/liter and for
A. terreus
7.90 (5.20 to 12.29) mg/liter (
P
< 0.001). A differential
in vitro
activity of amphotericin B was found among
Aspergillus
species despite the same MIC in the order
A. fumigatus
>
A. flavus
>
A. terreus
in the
in vitro
PK/PD model, possibly reflecting the different concentration- and time-dependent inhibitory/killing activities amphotericin B exerted against these species.
FeoB-Mediated Uptake of Iron by Francisella tularensis
Authors: Thomas-Charles Cindy A. , Zheng Huaixin , Palmer Lance E. , Mena Patricio , Thanassi David G. , Furie Martha B.
Published: May 2013

Francisella tularensis
, the bacterial cause of tularemia, infects the liver and replicates in hepatocytes
in vivo
and
in vitro
. However, the factors that govern adaptation of
F. tularensis
to the intrahepatocytic niche have not been identified. Using cDNA microarrays, we determined the transcriptional profile of the live vaccine strain (LVS) of
F. tularensis
grown in the FL83B murine hepatocytic cell line compared to that of
F. tularensis
cultured in broth. The
fslC
gene of the
fsl
operon was the most highly upregulated. Deletion of
fslC
eliminated the ability of the LVS to produce siderophore, which is involved in uptake of ferric iron, but it did not impair its growth in hepatocytes, A549 epithelial cells, or macrophages. Therefore, we sought an alternative means by which
F. tularensis
might obtain iron. Deletion of
feoB
, which encodes a putative ferrous iron transporter, retarded replication of the LVS in iron-restricted media, reduced its growth in hepatocytic and epithelial cells, and impaired its acquisition of iron. Survival of mice infected intradermally with a lethal dose of the LVS was slightly improved by deletion of
fslC
but was not altered by loss of
feoB
. However, the Δ
feoB
mutant showed diminished ability to colonize the lungs, liver, and spleen of mice that received sublethal inocula. Thus, FeoB represents a previously unidentified mechanism for uptake of iron by
F. tularensis
. Moreover, failure to produce a mutant strain lacking both
feoB
and
fslC
suggests that FeoB and the proteins of the
fsl
operon are the only major means by which
F. tularensis
acquires iron.
Escherichia coli Heat-Stable Toxin b Impairs Intestinal Epithelial Barrier Function by Altering Tight Junction Proteins
Authors: Ngendahayo Mukiza Clément , Dubreuil J. Daniel
Published: May 2013

Escherichia coli
heat-stable toxin b (STb) causes diarrhea in animals. STb binds to sulfatide, its receptor, and is then internalized. In the cytoplasm, through a cascade of events, STb triggers the opening of ion channels, allowing ion secretion and water loss and leading to diarrhea. Tight junctions (TJs) are well known for controlling paracellular traffic of ions and water by forming a physical intercellular barrier in epithelial cells, and some bacterial toxins are known to affect adversely TJs. The present study aimed at determining the effect of STb on TJs. T84 cells were treated for 24 h with purified STb and a nontoxic STb mutant (D30V). Transepithelial resistance (TER), paracellular flux marker, and confocal microscopy were used to analyze the effect of STb on TJs. Purified STb caused a significant reduction of TER parallel to an increase in paracellular permeability compared to the results seen in untreated cells or mutant D30V. The increased paracellular permeability was associated with a marked alteration of F-actin stress fibers. F-actin filament dissolution and condensation were accompanied by redistribution and/or fragmentation of ZO-1, claudin-1, and occludin. These changes were also observed following treatment of T84 cells with an 8-amino-acid peptide found in the STb sequence corresponding to a consensus sequence of
Vibrio cholerae
Zot toxin. These effects were not observed with a scrambled peptide or mutant D30V. Our findings indicate that STb induces epithelial barrier dysfunction through changes in TJ proteins that could contribute to diarrhea.
Differential Virulence and Disease Progression following Mycobacterium tuberculosis Complex Infection of the Common Marmoset (Callithrix jacchus)
Authors: Via Laura E. , Weiner Danielle M. , Schimel Daniel , Lin Philana Ling , Dayao Emmanuel , Tankersley Sarah L. , Cai Ying , Coleman M. Teresa , Tomko Jaime , Paripati Praveen , Orandle Marlene , Kastenmayer Robin J. , Tartakovsky Michael , Rosenthal Alexander , Portevin Damien , Eum Seok Yong , Lahouar Saher , Gagneux Sebastien , Young Douglas B. , Flynn JoAnne L. , Barry Clifton E.
Published: May 2013

Existing small-animal models of tuberculosis (TB) rarely develop cavitary disease, limiting their value for assessing the biology and dynamics of this highly important feature of human disease. To develop a smaller primate model with pathology similar to that seen in humans, we experimentally infected the common marmoset (Callithrix jacchus) with diverse strains ofMycobacterium tuberculosisof various pathogenic potentials. These included recent isolates of the modern Beijing lineage, the Euro-American X lineage, andM. africanum. All three strains produced fulminant disease in this animal with a spectrum of progression rates and clinical sequelae that could be monitored in real time using 2-deoxy-2-[18F]fluoro-d-glucose (FDG) positron emission tomography (PET)/computed tomography (CT). Lesion pathology at sacrifice revealed the entire spectrum of lesions observed in human TB patients. The three strains produced different rates of progression to disease, various extents of extrapulmonary dissemination, and various degrees of cavitation. The majority of live births in this species are twins, and comparison of results from siblings with different infecting strains allowed us to establish that the infection was highly reproducible and that the differential virulence of strains was not simply host variation. Quantitative assessment of disease burden by FDG-PET/CT provided an accurate reflection of the pathology findings at necropsy. These results suggest that the marmoset offers an attractive small-animal model of human disease that recapitulates both the complex pathology and spectrum of disease observed in humans infected with variousM. tuberculosisstrain clades.
Human Embryonic Stem Cell Lines Model Experimental Human Cytomegalovirus Latency
Authors: Penkert Rhiannon R. , Kalejta Robert F.
Published: May 2013

Herpesviruses are highly successful pathogens that persist for the lifetime of their hosts primarily because of their ability to establish and maintain latent infections from which the virus is capable of productively reactivating. Human cytomegalovirus (HCMV), a betaherpesvirus, establishes latency in CD34
+
hematopoietic progenitor cells during natural infections in the body. Experimental infection of CD34
+
cells
ex vivo
has demonstrated that expression of the viral gene products that drive productive infection is silenced by an intrinsic immune defense mediated by Daxx and histone deacetylases through heterochromatinization of the viral genome during the establishment of latency. Additional mechanistic details about the establishment, let alone maintenance and reactivation, of HCMV latency remain scarce. This is partly due to the technical challenges of CD34
+
cell culture, most notably, the difficulty in preventing spontaneous differentiation that drives reactivation and renders them permissive for productive infection. Here we demonstrate that HCMV can establish, maintain, and reactivate
in vitro
from experimental latency in cultures of human embryonic stem cells (ESCs), for which spurious differentiation can be prevented or controlled. Furthermore, we show that known molecular aspects of HCMV latency are faithfully recapitulated in these cells. In total, we present ESCs as a novel, tractable model for studies of HCMV latency.

IMPORTANCE
Human cytomegalovirus (HCMV) is a significant human pathogen that is known for causing birth defects, blindness in AIDS patients, and organ transplant rejection. The ability of HCMV to cause disease is dependent upon its capacity to establish and maintain latent infections. Very few of the molecular mechanisms of latency have been elucidated, due in part to the lack of a tractable cell culture model. Here we present embryonic stem cells (ESCs) as a model for HCMV latency, one in which genome maintenance and reactivation could be closely monitored. HCMV establishes latency in ESCs in the same fashion as it does in CD34
+
cells, the currently favored
in vitro
model. Hence, ESCs represent a novel model with unique properties, such as the ability to be genetically manipulated and cultured indefinitely in an undifferentiated state, that will facilitate the mechanistic examination of certain aspects of HCMV latency that have proven technically challenging in other model systems.
Metagenomic
De Novo
Assembly of an Aquatic Representative of the Verrucomicrobial Class
Spartobacteria
Authors: Herlemann Daniel P. R. , Lundin Daniel , Labrenz Matthias , Jürgens Klaus , Zheng Zongli , Aspeborg Henrik , Andersson Anders F.
Published: May 2013

The verrucomicrobial subdivision 2 class
Spartobacteria
is one of the most abundant bacterial lineages in soil and has recently also been found to be ubiquitous in aquatic environments. A 16S rRNA gene study from samples spanning the entire salinity range of the Baltic Sea indicated that, in the pelagic brackish water, a phylotype of the
Spartobacteria
is one of the dominating bacteria during summer. Phylogenetic analyses of related 16S rRNA genes indicate that a purely aquatic lineage within the
Spartobacteria
exists. Since no aquatic representative from the
Spartobacteria
has been cultured or sequenced, the metabolic capacity and ecological role of this lineage are yet unknown. In this study, we reconstructed the genome and metabolic potential of the abundant Baltic Sea
Spartobacteria
phylotype by metagenomics. Binning of genome fragments by nucleotide composition and a self-organizing map recovered the near-complete genome of the organism, the gene content of which suggests an aerobic heterotrophic metabolism. Notably, we found 23 glycoside hydrolases that likely allow the use of a variety of carbohydrates, like cellulose, mannan, xylan, chitin, and starch, as carbon sources. In addition, a complete pathway for sulfate utilization was found, indicating catabolic processing of sulfated polysaccharides, commonly found in aquatic phytoplankton. The high frequency of glycoside hydrolase genes implies an important role of this organism in the aquatic carbon cycle. Spatiotemporal data of the phylotype’s distribution within the Baltic Sea indicate a connection to
Cyanobacteria
that may be the main source of the polysaccharide substrates.

IMPORTANCE
The ecosystem roles of many phylogenetic lineages are not yet well understood. One such lineage is the class
Spartobacteria
within the
Verrucomicrobia
that, despite being abundant in soil and aquatic systems, is relatively poorly studied. Here we circumvented the difficulties of growing aquatic
Verrucomicrobia
by applying shotgun metagenomic sequencing on a water sample from the Baltic Sea. By using a method based on sequence signatures, we were able to
in silico
isolate genome fragments belonging to a phylotype of the
Spartobacteria
. The genome, which represents the first aquatic representative of this clade, encodes a diversity of glycoside hydrolases that likely allow degradation of various complex carbohydrates. Since the phylotype cooccurs with
Cyanobacteria
, these may be the primary producers of the carbohydrate substrates. The phylotype, which is highly abundant in the Baltic Sea during summer, may thus play an important role in the carbon cycle of this ecosystem.
Delayed presentation of diaphragmatic rupture after blast injury
Authors: Weerink Linda B M , Ten Duis K , Van der Velde D , Rakic S
Published: May 2013

A diaphragmatic injury is usually associated with injury to thoracic or abdominal organs due to blunt or penetrating trauma, and is uncommon after blast injury. We describe a patient with respiratory distress due to herniation of the stomach into the chest through a diaphragmatic injury, sustained 1 year previously when he suffered a blast injury while on deployed military operations, but without obvious visceral injury at that time. At emergency laparotomy there was a gastric perforation which was exteriorised as a gastrostomy and the diaphragmatic rupture closed. Postoperative pneumonia and pelvic abscess were both treated successfully and he left the hospital in good condition. Delayed treatment of traumatic diaphragmatic injury leads to an increased risk for herniation and/or strangulation of abdominal organs, which can be life-threatening. Recognising the symptoms indicating diaphragmatic injury is especially important in cases in which the relationship to previous trauma is less clear.
Colombian-style emerald mineralization in the northern Canadian Cordillera: integration into a regional Paleozoic fluid flow regime
Authors: Hewton M.L. , Marshall D.D. , Ootes L. , Loughrey L.E. , Creaser R.A.
Published: May 2013

Emerald in the Mackenzie Mountains is hosted in extensional quartz–carbonate veins cutting organic-poor Neoproterozoic sandstones and siltstones within the hanging wall of a thrust fault that emplaced these strata above Paleozoic rocks. Isotopic compositions of water extracted from emerald are typical of evolved sedimentary sulphate brines. Fluid inclusion studies indicate two saline fluid populations: a CO2–N2-bearing, high-salinity brine (20.4–25.8 wt.% NaCl equivalent), and a gas-free, saline brine (7.6–15.3 wt.% NaCl equivalent). Both populations display evidence of post-entrapment volume changes. δ18OVSMOW (VSMOW, Vienna standard mean ocean water) values for emerald, quartz, and dolomite yield averages of 17.3‰ (±0.9), 19.6‰ (±1.5), and 18.1‰ (±1.0), respectively. Dolomite δ13CVPDB (VPDB, Vienna Pee Dee belemnite) averages –6.8‰ (±1.0). Two pyrite samples returned δ34SCDT (CDT, Cañon Diablo troilite) values of 5.1‰ and 11.2‰. Triply concordant mineral equilibration temperatures determined from mineral pair δ18OVSMOW equilibration (quartz–emerald, quartz–dolomite, emerald–dolomite) range from 380 to 415 °C. Depth calculations based on mineral pair isotope equilibration and typical geothermal gradient indicate vein formation at 6–11 km depth. A Re–Os isochron age of 345 ± 20 Ma from pyrite indicates that mineralization was contemporaneous with estimated ages of some northern Cordilleran Zn–Pb occurrences. Emerald mineralization resulted from inorganic thermochemical sulphate reduction via the circulation of warm basinal brines through siliciclastic, carbonate, and evaporitic rocks. These brines were driven along deep basement structures and reactivated normal faults during the development of a trans-tensional back-arc basin during the late Devonian to middle Mississippian. The Mountain River emerald occurrence thus represents a variant of the Colombian-type emerald deposit model requiring thermochemical sulphate reduction.
Regional-scale patterns in community concordance: testing the roles of historical biogeography versus contemporary abiotic controls in determining stream community composition
Authors: Neff Margaret R. , Jackson Donald A.
Published: May 2013

The determinants of a local-scale biological community can include both abiotic and biotic factors acting at a variety of spatial and temporal scales. Previous studies have shown that the Precambrian Shield, a broad-scale geological feature, has distinct abiotic conditions and aquatic communities in lotic systems as compared with systems off-Shield. The relative importance of historical biogeography and postglacial colonization in Ontario versus the role of contemporary abiotic conditions has been debated in determining fish community composition. In this study, we sampled fish and macroinvertebrate community data from south-central Ontario streams to examine the degree of community concordance between fishes and macroinvertebrates and to determine the main abiotic drivers for this biological distinction between Shield and off-Shield areas. This study shows that low-order lotic systems on the Shield differ both abiotically and biotically from adjacent off-Shield systems and that similar abiotic drivers are responsible for structuring both groups of taxa. However, water chemistry and land-use variables are the most important in structuring macroinvertebrate communities, whereas physical habitat plays a larger role for fish communities.
Paléophytogéographie de la formation de Scarborough : nouvelles données et implications
Authors: Richard Pierre JH , Occhietti Serge , Clet Martine , Larouche Alayn C
Published: May 2013

Palynological study of the upper part of the Don Formation, in the Toronto area, confirms the progressive change from a mixed forest with numerous thermophilous trees (Quercus, Ulmus, Carya) to a cold balsam fir forest (Abies balsamea, Picea mariana, Pinus banksiana) towards the end of the Sangamonian climatic optimum. The Scarborough Formation pollen content indicates a forest-tundra or treed tundra environment similar to modern subarctic conditions. Macrofossil content also points to harsh climatic conditions. Mean annual temperature could then have been 10°C lower than the present in the Toronto area. Our data refute the reconstruction of a climatic cycle (cold-warmer-cold) within the Scarborough Formation. To explain the simultaneous presence of floristic elements typical of presently contrasted climatic regions (cold boreal, warm temperate), we propose that Lake Scarborough acted as a climatic buffer for riverine plants: thermophilous species survived in an englaciation context in remote regions. The upper part of the Don Formation corresponds with the end of the Sangamonian climatic optimum (end of isotopic substage 5e). After a sedimentary gap of unknown duration, the Scarborough Formation is apparently correlative to the Lévrard Till in the Middle St. Lawrence River Valley (isotopic stage 5b).