bluuebunny/crossref_metadata_2025 huggingface dataset:
Phylogenetically Distinct Cellulose Synthase Genes Support Secondary Wall Thickening in Arabidopsis Shoot Trichomes and Cotton Fiber
Authors: Betancur Lissete , Singh Bir , Rapp Ryan A. , Wendel Jonathan F. , Marks M. David , Roberts Alison W. , Haigler Candace H.
Published: February 2010

Through exploring potential analogies between cotton seed trichomes (or cotton fiber) and arabidopsis shoot trichomes we discovered that CesAs from either the primary or secondary wall phylogenetic clades can support secondary wall thickening. CesA genes that typically support primary wall synthesis, AtCesA1,2,3,5, and 6, underpin expansion and secondary wall thickening of arabidopsis shoot trichomes. In contrast, apparent orthologs of CesA genes that support secondary wall synthesis in arabidopsis xylem, AtCesA4,7, and 8, are up‐regulated for cotton fiber secondary wall deposition. These conclusions arose from: (a) analyzing the expression of CesA genes in arabidopsis shoot trichomes; (b) observing birefringent secondary walls in arabidopsis shoot trichomes with mutations in AtCesA4, 7, or 8; (c) assaying up‐regulated genes during different stages of cotton fiber development; and (d) comparing genes that were co‐expressed with primary or secondary wall CesAs in arabidopsis with genes up‐regulated in arabidopsis trichomes, arabidopsis secondary xylem, or cotton fiber during primary or secondary wall deposition. Cumulatively, the data show that: (a) the xylem of arabidopsis provides the best model for secondary wall cellulose synthesis in cotton fiber; and (b) CesA genes within a “cell wall toolbox” are used in diverse ways for the construction of particular specialized cell walls.
What Do We Really Know about Cellulose Biosynthesis in Higher Plants?
Authors: Guerriero Gea , Fugelstad Johanna , Bulone Vincent
Published: February 2010

Cellulose biosynthesis is one of the most important biochemical processes in plant biology. Despite the considerable progress made during the last decade, numerous fundamental questions related to this key process in plant development are outstanding. Numerous models have been proposed through the years to explain the detailed molecular events of cellulose biosynthesis. Almost all models integrate solid experimental data with hypotheses on several of the steps involved in the process. Speculative models are most useful to stimulate further research investigations and bring new exciting ideas to the field. However, it is important to keep their hypothetical nature in mind and be aware of the risk that some undemonstrated hypotheses may progressively become admitted. In this review, we discuss the different steps required for cellulose formation and crystallization, and highlight the most important specific aspects that are supported by solid experimental data.
General two-dimensional least-squares image subtraction
Authors: Quinn J. L. , Clocchiatti A. , Hamuy M.
Published: February 2010

A very general two-dimensional solution to the image convolution problem is presented extending the least-squares approach of Bramich. Image convolution is of wide applicability in astronomical data reduction including, but not limited to, light-curve analysis, microlensing and planet transits. The authors present the solution in a manner of interest to someone wishing to code a spatially varying implementation of the least-squares method.
CHANGES IN THE EFFECTIVENESS OF CHLORINE TREATMENTS DURING COLONIZATION OF SALMONELLA MONTEVIDEO ON TOMATOES
Authors: ITURRIAGA MONTSERRAT H. , ESCARTÍN EDUARDO F.
Published: February 2010

Inactivation of pathogens in produce is an essential approach for mitigating the risk of disease. A study was undertaken to compare the efficacy of chlorine to kill Salmonella Montevideo cells during colonization on the surface of tomatoes. Tomatoes (Lycopersicum esculentum) were spot‐inoculated with 100 µL (ca. 8 log cfu) of S. Montevideo. To promote attachment, inoculated fruits were incubated for 90 min at 22C, then washed to remove unattached cells and stored at 30C and 97% relative humidity for up to 10 days. Periodically, tomatoes were treated with chlorine (1000 or 200 mg/L) or water (control). On day 0, treatments with 1000 or 200 mg/L of chlorine, and water reduced the pathogen population by approximately 5.0, 4.5 and 0.4 log cfu/tomato, respectively. The inactivation efficacy of the sanitizers decreased as the storage time elapsed. By the 7th day, the populations recovered from tomatoes treated with water and disinfectants were not significantly different (P < 0.5).

PRACTICAL APPLICATIONS

This study clearly shows how the effectiveness of chlorine is modified when treatments are applied to tomatoes several days after the contamination with a human pathogen took place. The diminished effect of disinfection treatments suggests that microorganisms colonizing on surfaces become more resistant to germicides, and that biofilms may provide protective sites, or both. The results also reinforce the concept that once contaminated, bacterial pathogens can persist on tomatoes throughout a normal distribution time.
Treatment of chromium‐bearing wastewaters with constructed wetlands
Authors: Dotro Gabriela , Larsen Daniel , Palazolo Paul
Published: February 2010

Chromium can have detrimental effects on most organisms, including humans. The present study focused on the effect of treating chromium‐bearing, organic‐rich wastewater on constructed wetland performance. Eight laboratory‐scale systems were used to study organic matter and chromium removals, with three features tested in duplicate: media with proven chromium sorption capacity, vegetation presence and intermittent influent loading. A set of two wetlands acted as the base design. Average BOD5 and chromium removal rates were 13.4 g/m2 day and 135 mg Cr/m2 day, respectively. From an influent chromium concentration of 5 mg/L, <0.5 mg/L could be detected at the outlet during the study in all systems. Chromium removal efficiencies were statistically different for all systems (P<0.01), except when comparing the base design against the intermittent feed systems (P>0.05). Overall treatment performance of all systems was remarkably good in spite of significant chromium content and salinity.
The economic and social contribution of the zoological industry in Australia
Authors: BERI V. , TRANENT A. , ABELSON P.
Published: February 2010

This paper is based on a report that Aegis Consulting Australia and Applied Economics prepared for the Australasian Regional Association of Zoological Parks and Aquaria (ARAZPA) in March 2009. We discuss the zoological industry's contribution to the Australian economy and society in terms of the following items. • Economic value, that is Gross Domestic Product, employment and tourism. • Value for consumers, based on visitor survey results, financial support for zoos and consumer surplus. • Conservation value, including the type and results of in situ and ex situ programmes and research. • Education value, including success in raising conservation awareness and motivating behaviour change. • Value of contribution to bio‐security.  Our research is based on surveys and interviews with a range of stakeholders, including zoos, governments, consumers, industry representatives and conservation organizations. In the report, comparisons are drawn between government and private‐sector contributions to the financial upkeep of zoos and the contribution of zoos to the governments' conservation obligations and priorities, and the resultant savings to the public sector. In conclusion, the report finds that there is a strong case for governments to increase their contributions to zoos to assist in ongoing education, conservation and bio‐security services to the Australian and international community.
Protecting health care workers: a pandemic simulation based on Allegheny County
Authors: Cooley Philip , Lee Bruce Y. , Brown Shawn , Cajka James , Chasteen Bernadette , Ganapathi Laxminarayana , Stark James H. , Wheaton William D. , Wagener Diane K. , Burke Donald S.
Published: February 2010

Please cite this paper as: Cooley et al. (2010) Protecting health care workers: a pandemic simulation based on Allegheny County. Influenza and Other Respiratory Viruses 4(2), 61–72.

Background and Objectives  The Advisory Committee on Immunization Practices has identified health care workers (HCWs) as a priority group to receive influenza vaccine. Although the importance of HCW to the health care system is well understood, the potential role of HCW in transmission during an epidemic has not been clearly established.

Methods  Using a standard SIR (Susceptible–Infected–Recovered) framework similar to previously developed pandemic models, we developed an agent‐based model (ABM) of Allegheny County, PA, that incorporates the key health care system features to simulate the spread of an influenza epidemic and its effect on hospital‐based HCWs.

Findings  Our simulation runs found the secondary attack rate among unprotected HCWs to be approximately 60% higher (54·3%) as that of all adults (34·1%), which would result in substantial absenteeism and additional risk to HCW families. Understanding how a pandemic may affect HCWs, who must be available to treat infected patients as well as patients with other medical conditions, is crucial to policy makers’ and hospital administrators’ preparedness planning.
A novel electrochemical device to differentiate pandemic (H1N1) 2009 from seasonal influenza
Authors: Straight T. M. , Merrill G. , Perez L. , Livezey J. , Robinson B. , Lodes M. , Suciu D. , Anderson B.
Published: February 2010

Please cite this paper as: Straight et al. (2010) A novel electrochemical device to differentiate pandemic (H1N1) 2009 from seasonal influenza. Influenza and Other Respiratory Viruses 4(2), 73–79.

Background  One of the challenges of the recent pandemic (H1N1) 2009 influenza outbreak was to differentiate the virus from seasonal influenza when confronting clinical cases. The determination of the virus has implications on treatment choice, and obvious epidemiologic significance.

Objectives  We set out to apply a novel electrochemical device to samples derived from clinical cases of pandemic (H1N1) 2009 influenza to examine the ability of the device to differentiate these samples from cases of seasonal influenza.

Patients/Methods  An IRB approved protocol allowed for the use of original nasal wash samples from 24 confirmed human cases pandemic (H1N1) 2009 influenza. Clinical samples from cases of seasonal influenza (Influenza A/H1N1, A/H3N2, and B) were included as controls. Nucleic acids were extracted and samples examined by the ElectraSense® Influenza A assay (CombiMatrix, Inc). Samples were also examined by RT‐PCR or Luminex assays as a comparator.

Results and Conclusions  The ElectraSense® Influenza A assay correctly identified 23 of 24 samples of laboratory‐confirmed pandemic (H1N1) 2009 Influenza. The assay correctly identified all samples of influenza A/H1N1 and A/H3N2, and differentiated these from pandemic (H1N1) 2009 Influenza in all cases. The ElectraSense® Influenza A assay proved to be a useful assay to quickly and accurately differentiate pandemic (H1N1) 2009 influenza from seasonal influenza.
The Spanish influenza pandemic in occidental Europe (1918–1920) and victim age
Authors: Erkoreka Anton
Published: February 2010

Please cite this paper as: Erkoreka A. (2010) The Spanish influenza pandemic in occidental Europe (1918–1920) and victim age. Influenza and Other Respiratory Viruses 4(2), 81–89.

Background  Studies of the Spanish Influenza pandemic (1918–1920) provide interesting information that may improve our preparation for present and future influenza pandemic threats.

Methods  We studied archives from France, Italy, Spain and Portugal, obtaining high‐quality data that allowed us to calculate mortality rates associated with the Spanish flu and to characterize the proportional distribution of influenza deaths by age in the capital cities of these countries.

Results  French and American troops who fought in the First World War began to be affected from April 1918 onwards by a benign influenza epidemic, which hardly caused any deaths. The first occidental European country in which the pandemic spread to large sectors of the population, causing serious mortality, was Spain. The associated influenza provoked in Madrid a mortality rate of 1·31 per 1000 inhabitants between May and June (1918). In the following months of June and July, the epidemic spread to Portugal, but did not reach the Pyrenees. In September 1918, the influenza pandemic spread with tremendous virulence, presenting itself simultaneously during the month of October in South Western European countries. In Madrid, the 1918 excess mortality due in large part to the influenza pandemic is estimated at 5·27 per 1000. In Paris, the 1918 mortality rate provoked by the influenza and pathologies of the respiratory system was 6·08 per 1000. In South Western European countries, mortality rates oscillated between 10·6 and 12·1 per 1000 inhabitants. A study of the age distribution of deaths due to influenza between 1916 and 1921 reveals that the Spanish influenza principally affected men and women between 15 and 44 years of age. Deaths associated with the seasonal influenza of 1916, 1917 and 1921 represented 19·7%, 12·5% and 21·0% of all deaths respectively, whereas during the rawest moments of the Spanish influenza, in 1918, the proportion of deaths due to flu for those aged between 15 and 44 years of age reached 68·2% in Paris and 66·3% in Madrid.

Conclusion  Victim age is an important criterion that can be used to evaluate the phase and evolution of pandemic influenza. The Spanish Influenza affected particularly the 25‐ to 34‐year‐old and 15‐ to 24‐year‐old age groups.
Low‐pathogenic notifiable avian influenza serosurveillance and the risk of infection in poultry – a critical review of the European Union active surveillance programme (2005–2007)
Authors: Gonzales J. L. , Elbers A. R. W. , Bouma A. , Koch G. , De Wit J. J. , Stegeman J. A.
Published: February 2010

Please cite this paper as: Gonzales et al. (2010) Low‐pathogenic notifiable avian influenza serosurveillance and the risk of infection in poultry – a critical review of the European Union active surveillance programme (2005–2007). Influenza and Other Respiratory Viruses 4(2), 91–99.

Background  Since 2003, Member States (MS) of the European Union (EU) have implemented serosurveillance programmes for low pathogenic notifiable avian influenza (LPNAI) in poultry. To date, there is the need to evaluate the surveillance activity in order to optimize the programme’s surveillance design.

Objectives  To evaluate MS sampling operations [sample size and targeted poultry types (PTs)] and its relation with the probability of detection and to estimate the PTs relative risk (RR) of being infected.

Methods  Reported data of the surveillance carried out from 2005 to 2007 were analyzed using: (i) descriptive indicators to characterize both MS sampling operations and its relation with the probability of detection and the LPNAI epidemiological situation, and (ii) multivariable methods to estimate each PTs RR of being infected.

Results  Member States sampling a higher sample size than that recommended by the EU had a significantly higher probability of detection. Poultry types with ducks & geese, game‐birds, ratites and “others” had a significant higher RR of being seropositive than chicken categories. The seroprevalence in duck & geese and game‐bird holdings appears to be higher than 5%, which is the EU‐recommended design prevalence (DP), while in chicken and turkey categories the seroprevalence was considerably lower than 5% and with that there is the risk of missing LPNAI seropositive holdings.

Conclusion  It is recommended that the European Commission discusses with its MS whether the results of our evaluation calls for refinement of the surveillance characteristics such as sampling frequency, the between‐holding DP and MS sampling operation strategies.
Pre‐dispensing of antivirals to high‐risk individuals in an influenza pandemic
Authors: Goldstein Edward , Miller Joel C. , O’Hagan Justin J. , Lipsitch Marc
Published: February 2010

Please cite this paper as: Goldstein et al. (2010) Pre‐dispensing of antivirals to high‐risk individuals in an influenza pandemic. Influenza and other Respiratory Viruses 4(2), 101‐112.

We consider the net benefits of pre‐dispensing antivirals to high‐risk individuals during an influenza pandemic, where the measure of the benefit is the number of severe outcomes (such as deaths or hospitalizations) prevented by antivirals in the whole population. One potential benefit of pre‐dispensing is that individuals to whom antivirals have been pre‐dispensed may be able to initiate treatment earlier than if they had to wait to obtain and fill a prescription, reducing their risk of progression to severe disease. If this benefit exceeds the side effects of misuse for the category of individuals to whom antivirals were pre‐dispensed, and if antiviral supply exceeds overall population demand (which appears relevant for several countries including US in the 2009 H1N1 pandemic), pre‐dispensing a quantity of antivirals not exceeding the difference between supply and demand is always beneficial. In this study, we consider the net benefits of pre‐dispensing antivirals under various scenarios, including demand exceeding supply, and derive mathematical conditions under which antiviral pre‐dispensing is advantageous on balance. For individuals whose relative risk of severe outcome is high enough, such as immunosuppressed individuals (particularly children) and possibly individuals with neurological disorders, pre‐dispensing is always beneficial at a given level of antiviral stockpile with modest assumptions on the relative benefit of early treatment by a pre‐dispensed course, regardless of the overall population demand for antivirals during the course of an epidemic. Making additional assumptions on either the overall population demand for antivirals (which appear relevant for the 2009 H1N1 pandemic) or on the relative benefit of pre‐dispensing would make pre‐dispensing net beneficial with inclusion of a larger number of persons such as pregnant women and morbidly obese adults.
National review of state wildlife action plans for Odonata species of greatest conservation need
Authors: BRIED JASON T. , MAZZACANO CELESTE A.
Published: February 2010

Abstract.  1. The overarching goal of United States wildlife action plans is to prevent wildlife from becoming endangered or declining to levels where recovery becomes unlikely. Effective plan implementation depends on establishing Species of Greatest Conservation Need (SGCN), defined as wildlife species with small or declining populations or other characteristics that make them vulnerable.

2. Although nearly two‐thirds of distinct Odonata species known from the U.S. (441 species as of 2005) were appointed as SGCN, over half the states neglected to assign dragonfly SGCN, damselfly SGCN, or both. Western and southern states listed proportionately fewer odonate SGCN than states of the Great Lakes, Mid‐Atlantic, and New England regions, apparently reflecting geographic patterns of legal authority, available information, and involvement by Odonata specialists.

3. Greater consultation of Odonata specialists is encouraged in any revision of state wildlife action plans, along with increased: (i) use of existing conservation lists, (ii) inferences from field guides and major faunal synopses, (iii) recognition of patterns of endemism, and (iv) application of empirical species distribution modelling.

4. Legal and management restrictions aside, insects and other invertebrates are often neglected in mainstream conservation efforts because they are perceived as understudied. It is erroneous to assume ‘not enough information’ exists for well‐studied microfauna such as Odonata and doing so further undermines the conservation of less conspicuous and charismatic taxa.
Does one community shape the other? Dragonflies and fish in Swedish lakes
Authors: WITTWER TORBEN , SAHLÉN GÖRAN , SUHLING FRANK
Published: February 2010

Abstract. 1. Freshwater communities are often structured by predation. In permanent lentic freshwater habitats dragonfly larvae are major predators which, in return, suffer predation by fish. Antipredator traits vary between the dragonfly species, and the dragonfly communities are therefore shaped by the presence of fish. But fish communities vary, and as different fish species affect dragonflies in different ways, the species composition of the fish community may affect the composition of the dragonfly community.

2. We sampled dragonfly larvae in 24 lakes with a known fish stock in south‐western Sweden, and explored the impact of fish as well as vegetation structure on dragonfly communities by means of multivariate analyses.

3. We found that the presence of four fish species affected the community structure of dragonflies. The impact strength depended mainly on the abundance ofPerca fluviatilis, with which most dragonfly species were negatively correlated. Many dragonfly species were also positively correlated with the occurrence of at least one fish species, which may reflect similar habitat requirements or imply indirect positive effects of these fish species.

4. Of the 24 recorded dragonfly species, four did not occur in lakes dominated byP. fluviatilis, whereas only one species was lacking in lakes dominated byRutilus rutilus. The dragonfly species diversity was higher inR. rutiluslakes than inP. fluviatilislakes.

5. Our results suggest that the fish species composition is a major determinant of the dragonfly community, which in turn will influence the lower trophic levels.
Distribution of hepatic stem cell markers in human liver with massive hepatic necrosis
Authors: Hwang Jeong Eun , Han Sang Hak , Kim Ji‐Hun , Cho Yong‐Mee , Yu Eunsil
Published: February 2010

Background and aims: The origin, niche, and function of human hepatic stem/progenitor cells (HHSPCs) have been longstanding areas of debate. We designed this study to elucidate the distribution of potential HHSPCs during the various stages of regeneration by the expression of known HHSPC markers. Methods: Immunostainings for c‐kit, cytokeratin (CK)19, and CD133 were performed in cases of massive hepatic necrosis (MHN) in various regenerating stages. Results: We identified c‐kit‐positive cells as single cells primarily in the stroma of portal tracts but rarely in the sinusoids. There were no differences in the numbers or distribution of c‐kit positive cells according to MHN regeneration stage. The number of CK19‐positive cells mostly in a ductular arrangement significantly increased along the interface, and single cells or small clusters of CK19‐positive cells were occasionally observed in the sinusoid in cases of MHN. CD133‐positive cells were located in ductular structures along the interface in cases of MHN, while no CD133‐positive cells were observed in the normal liver. Conclusion: The c‐kit‐ or CD133‐positive cells appear first at the limiting plate and are then organized into ductular structures or moved to the sinusoid as single cells or clusters during hepatic regeneration.
Adoption of Open Business Models in the West and Innovation in India's Software Industry
Authors: Lema Rasmus
Published: February 2010

Over the last three decades, outsourcing has had a big influence on the international division of labour. It is clear that it has been a major reason for the enormous build‐up of production capabilities in the developing world, in particular in the export platforms of Asia. However, the influence of outsourcing on innovation capabilities is less clear. Recent literature shows that innovation capabilities have emerged in the software cluster of Bangalore in India. This report asks whether and how the adoption of open business models in OECD countries had an influence on the rise of innovative software services in Bangalore. This requires detailed research on both the demand side and the supply side of outsourced software services. On the demand side, this report compares three software buyer segments, exploring the relationship between business models and outsourcing patterns. The study shows that the adoption of open business models in OECD countries has a major influence on the ‘space’ for innovation that accrues to suppliers in the software industry in India. On the supply side, the study investigates the factors that determine whether the new spaces are filled and how advanced innovation capabilities are built. The key feature of this study is that it examines the interaction between demand‐ and supply‐side dynamics. Most studies tend to focus on only one side, but the key is to see them in conjunction. The study shows that their co‐evolution over time changes not only the scale of outsourcing but also the ‘quality’ of the contents and the division of labour.
Transforming Children's Lives Through Innovation in Quality Education: Implications for Policy and Practice
Authors: Oswald Katy , Moriarty Kathleen
Published: February 2010

This report argues for an expansion of the understanding of quality basic education, to be education that empowers students and addresses the inter‐generational transmission of inequality and poverty. It argues that what is needed is an understanding of quality education that combines behaviourist and humanist approaches, infused with transformative education (TE) approaches. This report provides a framework for this broader understanding of quality education. It highlights evidence that shows transformative education approaches can help stimulate economic development, increase learning retention, lead to better cognitive performance and retention rates; increase civic engagement, raise human rights awareness to address discrimination; and promote reconciliation and reintegration. Most importantly, transformative education approaches are aimed at empowering students and can contribute to addressing inter‐generational transmissions of inequality and poverty. It concludes with three recommendations for policymakers: (1) to expand the assessment of ‘effective’ education to include broader education outcomes, including individual and social transformation, empowerment and learner's retention rates, rather than simple test scores; (2) to include transformative education approaches in pre‐ and in‐service training and as part of the mainstream teacher training curriculum, and; (3) that donors need to increase long‐term and predictable funding to meet the existing annual $7.2 billion gap in education financing globally.
Simple means to improve the interpretability of regression coefficients
Authors: Schielzeth Holger
Published: February 2010

1. Linear regression models are an important statistical tool in evolutionary and ecological studies. Unfortunately, these models often yield some uninterpretable estimates and hypothesis tests, especially when models contain interactions or polynomial terms. Furthermore, the standard errors for treatment groups, although often of interest for including in a publication, are not directly available in a standard linear model.

2. Centring and standardization of input variables are simple means to improve the interpretability of regression coefficients. Further, refitting the model with a slightly modified model structure allows extracting the appropriate standard errors for treatment groups directly from the model.

3. Centring will make main effects biologically interpretable even when involved in interactions and thus avoids the potential misinterpretation of main effects. This also applies to the estimation of linear effects in the presence of polynomials. Categorical input variables can also be centred and this sometimes assists interpretation.

4. Standardization (z‐transformation) of input variables results in the estimation of standardized slopes or standardized partial regression coefficients. Standardized slopes are comparable in magnitude within models as well as between studies. They have some advantages over partial correlation coefficients and are often the more interesting standardized effect size.

5. The thoughtful removal of intercepts or main effects allows extracting treatment means or treatment slopes and their appropriate standard errors directly from a linear model. This provides a simple alternative to the more complicated calculation of standard errors from contrasts and main effects.

6. The simple methods presented here put the focus on parameter estimation (point estimates as well as confidence intervals) rather than on significance thresholds. They allow fitting complex, but meaningful models that can be concisely presented and interpreted. The presented methods can also be applied to generalised linear models (GLM) and linear mixed models.
The Origins of Sexually Transmitted HIV Among Men Who Have Sex with Men
Authors: Butler David M. , Delport Wayne , Kosakovsky Pond Sergei L. , Lakdawala Malcolm K. , Cheng Pok Man , Little Susan J. , Richman Douglas D. , Smith Davey M.
Published: February 2010

Cell-free virus in seminal plasma is the origin of sexually transmitted HIV among men who have sex with men.
A Monoclonal Antibody Against α
V
β
3
Integrin Inhibits Development of Atherosclerotic Lesions in Diabetic Pigs
Authors: Maile Laura A. , Busby Walker H. , Nichols Timothy C. , Bellinger Dwight A. , Merricks Elizabeth P. , Rowland Michael , Veluvolu Umadevi , Clemmons David R.
Published: February 2010

An antibody directed at the C terminus of an integrin subunit can prevent the formation of atherosclerotic lesions in diabetic pigs.
Liberating Health Data for Clinical Research Applications
Authors: Nadler Jessica J. , Downing Gregory J.
Published: February 2010

Advances in communication and information technology infrastructure and policies to support exchange of health information are providing new opportunities for enhancing clinical research.
Like a Bridge over Troubled Waters: Innervation Changes in the Malfunctioning Heart
Authors: Buettner Christoph
Published: February 2010

Heart failure causes cardiac nerves to change the neurotransmitter they release, potentially protecting the heart.
A Preemptive Strike Against Resistant Tumor Cells
Authors: Morozov Alexei
Published: February 2010

A few cells within a tumor carry drug-resistance mutations even before treatment is initiated, providing an opportunity to squelch them early.
Pharmacokinetic-Pharmacodynamic Assessment of Faropenem in a Lethal Murine
Bacillus anthracis
Inhalation Postexposure Prophylaxis Model
Authors: Gill Stanley C. , Rubino Christopher M. , Bassett Jennifer , Miller Lynda , Ambrose Paul G. , Bhavnani Sujata M. , Beaudry Amber , Li Jinfang , Stone Kimberly Clawson , Critchley Ian , Janjic Nebojsa , Heine Henry S.
Published: February 2010

There are few options for prophylaxis after exposure to
Bacillus anthracis
, especially in children and women of childbearing potential. Faropenem is a β-lactam in the penem subclass that is being developed as an oral prodrug, faropenem medoxomil, for the treatment of respiratory tract infections. Faropenem was shown to have
in vitro
activity against
B. anthracis
strains that variably express the
bla1
β-lactamase (MIC range, ≤0.06 to 1 μg/ml). In this study we evaluated the pharmacokinetic-pharmacodynamic (PK-PD) relationships between the plasma faropenem free-drug (
f
) concentrations and efficacy against
B. anthracis
in a murine postexposure prophylaxis inhalation model. The plasma PKs and PKs-PDs of faropenem were evaluated in BALB/c mice following the intraperitoneal (i.p.) administration of doses ranging from 2.5 to 160 mg/kg of body weight. For the evaluation of efficacy, mice received by inhalation aerosol doses of
B. anthracis
(Ames strain; faropenem MIC, 0.06 μg/ml) at 100 times the 50% lethal dose. The faropenem dosing regimens (10, 20, 40, and 80 mg/kg/day) were administered i.p. at 24 h postchallenge at 4-, 6-, and 12-h intervals for 14 days. The sigmoid maximum-threshold-of-efficacy (
E
max
) model fit the survival data, in which the free-drug area under the concentration-time curve (
f
AUC)/MIC ratio, the maximum concentration of free drug in plasma (
fC
max
)/MIC ratio, and the cumulative percentage of a 24-h period that the free-drug concentration exceeds the MIC under steady-state pharmacokinetic conditions (
f
%
T
MIC
) were each evaluated. Assessment of
f
%
T
MIC
demonstrated the strongest correlation with survival (
R
2
= 0.967) compared to the correlations achieved by assessment of
f
AUC/MIC or
fC
max
/MIC, for which minimal correlations were observed. The 50% effective dose (ED
50
), ED
90
, and ED
99
corresponded to
f
%
T
MIC
values of 10.6, 13.4, and 16.4%, respectively, and
E
max
was 89.3%. Overall, faropenem demonstrated a high level of activity against
B. anthracis
in the murine postexposure prophylaxis inhalation model.
Changes in the Proteome of
Candida albicans
in Response to Azole, Polyene, and Echinocandin Antifungal Agents
Authors: Hoehamer Christopher F. , Cummings Edwin D. , Hilliard George M. , Rogers P. David
Published: February 2010

The yeast
Candida albicans
is an opportunistic human fungal pathogen and the cause of superficial and systemic infections in immunocompromised patients. The classes of antifungal agents most commonly used to treat
Candida
infections are the azoles, polyenes, and echinocandins. In the present study, we identified changes in
C. albicans
protein abundance using two-dimensional polyacrylamide gel electrophoresis and matrix-assisted laser desorption ionization-time of flight mass spectroscopy following exposure to representatives of the azole (ketoconazole), polyene (amphotericin B), and echinocandin (caspofungin) antifungals in an effort to elucidate the adaptive responses to these classes of antifungal agents. We identified 39 proteins whose abundance changed in response to ketoconazole exposure. Some of these proteins are involved in ergosterol biosynthesis and are associated with azole resistance. Exposure to amphotericin B altered the abundance of 43 proteins, including those associated with oxidative stress and osmotic tolerance. We identified 50 proteins whose abundance changed after exposure to caspofungin, including enzymes involved in cell wall biosynthesis and integrity, as well as the regulator of β-1,3-glucan synthase activity, Rho1p. Exposure to caspofungin also increased the abundance of the proteins involved in oxidative and osmotic stress. The common adaptive responses shared by all three antifungal agents included proteins involved in carbohydrate metabolism. Some of these antifungal-responsive proteins may represent potential targets for the development of novel therapeutics that could enhance the antifungal activities of these drugs.
Novel
FKS
Mutations Associated with Echinocandin Resistance in
Candida
Species
Authors: Garcia-Effron Guillermo , Chua Daniel Joseph , Tomada Jon Rupert , DiPersio Joseph , Perlin David S. , Ghannoum Mahmoud , Bonilla Hector
Published: February 2010

We studied three clinical isolates of
Candida
spp. (one
C. tropicalis
isolate and two
C. glabrata
isolates) from patients with invasive candidiasis. The first isolate emerged during echinocandin treatment, while the others emerged after the same treatment. These strains harbored an amino acid substitution in Fksp never linked before with reduced echinocandin susceptibility in
C. tropicalis
or in
C. glabrata
. The molecular mechanism of reduced susceptibility was confirmed using a 1,3-β-
d
-glucan synthase inhibition assay.
Dinitroaniline Activity inToxoplasma gondiiExpressing Wild-Type or Mutant α-Tubulin
Authors: Ma Christopher , Tran Johnson , Gu Frank , Ochoa Roxanna , Li Catherine , Sept David , Werbovetz Karl , Morrissette Naomi
Published: February 2010

The human parasiteToxoplasma gondiiis sensitive to dinitroaniline compounds which selectively disrupt microtubules in diverse protozoa but which have no detectable effect on vertebrate host cell microtubules or other functions. Replication of wild-typeT. gondiiis inhibited by 0.5 to 2.5 μM oryzalin, but mutant parasites harboring amino acid substitutions in the predicted dinitroaniline binding site confer resistance up to 40 μM oryzalin. However, the precise interaction between dinitroanilines and the binding site in α-tubulin remains unclear. We have investigated the activity of 12 dinitroanilines and the related compound amiprophos methyl on wild-type and dinitroaniline-resistant parasite lines that contain proposed binding site mutations. These data indicate that dinitramine is the most effective dinitroaniline to inhibitToxoplasmagrowth in wild-type parasites and most resistant lines. Dinitramine has an amine group at themetaposition not present in any of the other dinitroanilines tested here that is predicted to form hydrogen bonds with residues Arg2 and Gln133 according to docking data. Remarkably, although the binding site mutation Ile235Val confers increased resistance to most dinitroanilines, it confers increased sensitivity to GB-II-5, a compound optimized for activity against kinetoplastid tubulin. Kinetoplastid parasites have a valine at position 235 of α-tubulin, whereas apicomplexan parasites have an isoleucine at this site. We suggest that this heterogeneity in binding site environment influences relative dinitroaniline sensitivity in distinct protozoan lineages and hypothesize that a mutation that makes the apicomplexan dinitroaniline binding site more like the kinetoplastid site increases sensitivity to a dinitroaniline optimized for activity in the latter parasites.
Antistaphylococcal Activity of ACHN-490 Tested Alone and in Combination with Other Agents by Time-Kill Assay
Authors: Lin Gengrong , Ednie Lois M. , Appelbaum Peter C.
Published: February 2010

Synergy time-kill studies of 47 methicillin-resistant
Staphylococcus aureus
strains with differing resistance phenotypes showed that combinations of subinhibitory concentrations of ACHN-490 and daptomycin yielded synergy against 43/47 strains at 24 h, while the combination was indifferent against the remaining 4 strains. ACHN-490 and ceftobiprole showed synergy in 17/47 strains tested at 24 h, while 6/47 strains showed synergy for subinhibitory combinations of ACHN-490 and linezolid.
Fluoroquinolone Resistance in
Streptococcus dysgalactiae
subsp.
equisimilis
and Evidence for a Shared Global Gene Pool with
Streptococcus pyogenes
Authors: Pinho M. D. , Melo-Cristino J. , Ramirez M.
Published: February 2010

Quinolone resistance is an emerging problem in
Streptococcus pyogenes
, and recombination with
Streptococcus dysgalactiae
DNA has been implicated as a frequent mechanism leading to resistance. We have characterized a collection of
S. dysgalactiae
subsp.
equisimilis
isolates responsible for infections in humans (
n
= 314) and found a high proportion of levofloxacin-resistant isolates (12%). Resistance was associated with multiple
emm
types and genetic lineages, as determined by pulsed-field gel electrophoretic profiling. Since we could not find evidence for a role of efflux pumps in resistance, we sequenced the quinolone resistance-determining regions of the
gyrA
and
parC
genes of representative resistant and susceptible isolates. We found much greater diversity among the
parC
genes (19 alleles) than among the
gyrA
genes (5 alleles). While single mutations in either GyrA or ParC were sufficient to raise the MIC so that the strains were classified as intermediately resistant, higher-level resistance was associated with mutations in both GyrA and ParC. Evidence for recombination with
S. pyogenes
DNA was found in some
parC
alleles, but this was not exclusively associated with resistance. Our data support the existence of a common reservoir of genes conferring quinolone resistance shared between
S. dysgalactiae
subsp.
equisimilis
and
S. pyogenes
, while no recombination with the animal pathogen
S. dysgalactiae
subsp.
dysgalactiae
could be found.
Mutant APH(2″)-IIa Enzymes with Increased Activity against Amikacin and Isepamicin
Authors: Toth Marta , Frase Hilary , Chow Joseph W. , Smith Clyde , Vakulenko Sergei B.
Published: February 2010

Directed evolution by random PCR mutagenesis of the gene for the aminoglycoside 2″-IIa phosphotransferase generated R92H/D268N and N196D/D268N mutant enzymes, resulting in elevated levels of resistance to amikacin and isepamicin but not to other aminoglycoside antibiotics. Increases in the activities of the mutant phosphotransferases for isepamicin are the result of decreases in

K
m

values, while improved catalytic efficiency for amikacin is the result of both a decrease in

K
m

values and an increase in turnover of the antibiotic. Enzymes with R92H, D268N, and D268N single amino acid substitutions did not result in elevated MICs for aminoglycosides.
Correlation between
In
Vitro
Activity of Posaconazole and
In
Vivo
Efficacy against
Rhizopus oryzae
Infection in Mice
Authors: Rodríguez M. Mar , Pastor F. Javier , Sutton Deanna A. , Calvo Enrique , Fothergill Annette W. , Salas Valentina , Rinaldi Michael G. , Guarro Josep
Published: February 2010

We have evaluated the
in vitro
activity of posaconazole (PSC) against 50 clinical strains of
Rhizopus oryzae
using a broth microdilution method, the Neo-Sensitabs tablet diffusion method, and minimal fungicidal concentration (MFC) determination. In general, PSC showed low MICs against this fungus, and the MICs correlated with the inhibition zone diameters. Most of the MFCs, however, were from 1 to 4 dilutions higher than their corresponding MICs. We then investigated the efficacies of several different doses of PSC in a murine model. All treatments began 24 h after challenge and lasted for 7 days. The drug was administered twice a day to mice infected with three strains that showed intermediate PSC susceptibility (MIC = 2 μg/ml) and three PSC-susceptible strains (MIC = 0.25 μg/ml). A dose of 10 mg/kg of body weight was ineffective, while doses of 20 and 30 mg/kg prolonged the survival of the mice. The 50 strains tested were segregated into two groups on the basis of the
in vitro
data. For the group with the most strains (85%), the strains had low PSC MICs, mice infected with the strains showed higher rates of survival (30 to 40%), and PSC was able to reduce the fungal load in the kidney and less regularly in the brain. For the second group (15% of the strains), the strains had intermediate PSC MICs, mice infected with the strains had lower survival rates (10 to 20%), and PSC treatment resulted in variable and no reductions in the fungal loads in the kidneys and brains, respectively.
Crystal Structure of the Narrow-Spectrum OXA-46 Class D β-Lactamase: Relationship between Active-Site Lysine Carbamylation and Inhibition by Polycarboxylates
Authors: Docquier Jean-Denis , Benvenuti Manuela , Calderone Vito , Giuliani Francesco , Kapetis Dimos , De Luca Filomena , Rossolini Gian Maria , Mangani Stefano
Published: February 2010

Class D β-lactamases represent a heterogeneous group of active-site serine β-lactamases that show an extraordinary panel of functional features and substrate profiles, thus representing relevant models for biochemical and structural studies. OXA-46 is a narrow-spectrum enzyme belonging to the OXA-2 subgroup which was found in aPseudomonas aeruginosaclinical isolate from northern Italy. In this work, we obtained the three-dimensional structure of OXA-46, which shows the overall fold of active serine β-lactamases and a dimeric quaternary structure. Significant differences with currently available structures of class D β-lactamases were found in the loops located close to the active site, which differ in length and conformation. Interestingly, the three subunits present in the asymmetric unit showed some structural heterogeneity, only one of which presented a carbamylated lysine recognized as an important functional feature of class D enzymes. The carbamylation state of residue Lys75 appeared to be associated with different shapes and dimensions of the active site. Moreover, a tartrate molecule from the crystallization buffer was found in the active site of the noncarbamylated subunits, which interacts with catalytically relevant residues. The OXA-46 crystal asymmetric units thus interestingly present the structures of the free carbamylated active site and of the ligand-bound uncarbamylated active site, offering the structural basis for investigating the potential of new scaffolds of β-lactamase inhibitors.
Occurrence of ST23 Complex Phylogroup A
Escherichia coli
Isolates Producing Extended-Spectrum AmpC β-Lactamase in a French Hospital
Authors: Crémet Lise , Caroff Nathalie , Giraudeau Cécile , Dauvergne Sandie , Lepelletier Didier , Reynaud Alain , Corvec Stéphane
Published: February 2010

Extended-spectrum AmpC β-lactamase (ESAC)
Escherichia coli
producers were investigated over a 5-year period. Eleven isolates presenting a strong
ampC
promoter and different strategic AmpC mutations, including two newly described modifications (A292V and an L-A-A insertion at 295), were characterized. All the isolates belonged to phylogenetic group A and to the ST23 complex.
Stressor Exposure Disrupts Commensal Microbial Populations in the Intestines and Leads to Increased Colonization by
Citrobacter rodentium
Authors: Bailey Michael T. , Dowd Scot E. , Parry Nicola M. A. , Galley Jeffrey D. , Schauer David B. , Lyte Mark
Published: February 2010

The gastrointestinal tract is colonized by an enormous array of microbes that are known to have many beneficial effects on the host. Previous studies have indicated that stressor exposure can disrupt the stability of the intestinal microbiota, but the extent of these changes, as well as the effects on enteric infection, has not been well characterized. In order to examine the ability of stressors to induce changes in the gut microbiota, we exposed mice to a prolonged restraint stressor and then characterized microbial populations in the intestines using both traditional culture techniques and bacterial tag-encoded FLX amplicon pyrosequencing (bTEFAP). Exposure to the stressor led to an overgrowth of facultatively anaerobic microbiota while at the same time significantly reducing microbial richness and diversity in the ceca of stressed mice. Some of these effects could be explained by a stressor-induced reduction in the relative abundance of bacteria in the family
Porphyromonadaceae
. To determine whether these alterations would lead to increased pathogen colonization, stressed mice, as well as nonstressed controls, were challenged orally with the enteric murine pathogen
Citrobacter rodentium
. Exposure to the restraint stressor led to a significant increase in
C. rodentium
colonization over that in nonstressed control mice. The increased colonization was associated with increased tumor necrosis factor alpha (TNF-α) gene expression in colonic tissue. Together, these data demonstrate that a prolonged stressor can significantly change the composition of the intestinal microbiota and suggest that this disruption of the microbiota increases susceptibility to an enteric pathogen.