bluuebunny/crossref_metadata_2025 huggingface dataset:
Rules of the seed size game: contests between large‐seeded and small‐seeded species
Authors: Lönnberg Karin , Eriksson Ove
Published: December 2012

The coexistence of multiple seed size strategies within plant communities have been considered puzzling, based on a theoretical expectation of the existence of an optimal seed size under each set of specific environmental conditions. A model aimed at explaining the coexistence of different seed sizes has been suggested, where a seed size – seed number tradeoff is connected to a tradeoff between competition and colonization, leading to a competitive advantage in larger‐seeded species and a colonization advantage in smaller‐seeded species. Recently an alternative model has been suggested, based on a tradeoff between stress tolerance and fecundity, associated with the variation from large to small seeds. Here, we examine the role of seed size for recruitment in two‐species contests subjected to various treatments. In a garden experiment seeds of 14 plant species were combined pair‐wise into seven pairs, each with one larger‐seeded species and one smaller‐seeded species. Each species‐pair was sown with sparse and dense seed densities and subjected to different treatments of shading and litter. Recruitment was recorded during two years. Our results showed a general advantage of larger‐seeded species over smaller‐seeded species. This seed size advantage increased in treatments with litter, whereas there were minor effects of shade, and no effect of seed density was found. We thus found little support for a density dependent seed size game as assumed in models of a competition‐colonization tradeoff, whereas our results fit well with a model based on a tradeoff between stress tolerance and fecundity. Our experiment provides novel empirical data to theoretical models on co‐existence between multiple seed size strategies.
Standard Operating Procedures for Peyronie's Disease
Authors: Levine Laurence A. , Burnett Arthur L.
Published: December 2012

Introduction

Peyronie's disease (PD) refers to a penile deformity that is associated with sexual dysfunction.

Aim

To provide recommendations and Standard Operating Procedures (SOPs) based on best evidence for diagnosis and treatment of PD.

Methods

Medical literature was reviewed and combined with expert opinion of the authors.

Main Outcome Measures

Recommendations and SOPs based on grading of evidence–based medical literature.

Results

PD is a fibrotic wound-healing disorder involving the tunica albuginea of the corpora cavernosa. The resulting scar is responsible for a variety of deformities, including curvature, shortening, narrowing with hinge effect, and is frequently associated in the early phase with pain. Patients frequently experience diminished quality erections. All of these conditions can compromise sexual function for the affected male. The etiopathophysiology of PD has yet to be clarified and as a result, effective, reliable, mechanistic directed non-surgical therapy is lacking.

Conclusions

The management of PD consists of proper diagnosis and treatment, ranging from non-surgical to surgical interventions. The main state of treatment for PD rests at this time on surgical correction that should be based on clear indications, involve surgical consent, and follow a surgical algorithm that includes tunica plication, plaque incision/partial excision and grafting, and penile prosthesis implantation.
Effects of Increasing Salinity Stress and Decreasing Water Availability on Ecophysiological Traits of Quinoa (Chenopodium quinoa Willd.) Grown in a Mediterranean‐Type Agroecosystem
Authors: Cocozza C. , Pulvento C. , Lavini A. , Riccardi M. , d'Andria R. , Tognetti R.
Published: December 2012

Quinoa is a native Andean crop for domestic consumption and market sale, widely investigated due to its nutritional composition and gluten‐free seeds. Leaf water potential (Ψleaf) and its components and stomatal conductance (gs) of quinoa, cultivar Titicaca, were investigated in Southern Italy, in field trials (2009 and 2010). This alternative crop was subjected to irrigation treatments, with the restitution of 100 %, 50 % and 25 % of the water necessary to replenish field capacity, with well water (100 W, 50 W, 25 W) and saline water (100 WS, 50 WS, 25 WS) with an electrical conductivity (ECw) of 22 dS m−1. As water and salt stress developed and Ψleaf decreased, the leaf osmotic potential (Ψπ) declined (below −2.05 MPa) to maintain turgor. Stomatal conductance decreased with the reduction in Ψleaf (with a steep drop at Ψleaf between −0.8 and 1.2 MPa) and Ψπ (with a steep drop at Ψπ between −1.2 and −1.4 MPa). Salt and drought stress, in both years, did not affect markedly the relationship between water potential components, RWC and gs. Leaf water potentials and gs were inversely related to water limitation and soil salinity experimentally imposed, showing exponential (Ψleaf and turgor pressure, Ψp, vs. gs) or linear (Ψleaf and Ψp vs. SWC) functions. At the end of the experiment, salt‐irrigated plants showed a severe drop in Ψleaf (below −2 MPa), resulting in stomatal closure through interactive effects of soil water availability and salt excess to control the loss of turgor in leaves. The effects of salinity and drought resulted in strict dependencies between RWC and water potential components, showing that regulating cellular water deficit and volume is a powerful mechanism for conserving cellular hydration under stress, resulting in osmotic adjustment at turgor loss. The extent of osmotic adjustment associated with drought was not reflected in Ψπ at full turgor. As soil was drying, the association between Ψleaf and SWC reflected the ability of quinoa to explore soil volume to continue extracting available water from the soil. However, leaf ABA content did not vary under concomitant salinity and drought stress conditions in 2009, while differing between 100 W and 100 WS in 2010. Quinoa showed good resistance to water and salt stress through stomatal responses and osmotic adjustments that played a role in the maintenance of a leaf turgor favourable to plant growth and preserved crop yield in cropping systems similar to those of Southern Italy.
Melasma pathogenesis and influencing factors – an overview of the latest research
Authors: Passeron T.
Published: December 2012

Melasma is an acquired, symmetrical hypermelanosis of the face. The pathogenesis of melasma is complex and the treatment is often challenging with frequent relapses. Genetic background, exposure to ultraviolet radiation, and female sex hormones are classical influencing factors. To the light of the recent literature, other factors could promote melasma lesions. Moreover, there are increasing evidences showing that melanocytes are not the only cells involved, and that other players probably have a key role in the development and the relapses of melasma. Identifying those associated factors should provide new targets for a more efficient treatment of melasma and a better prevention of the relapses.
4‐n‐butylresorcinol, a highly effective tyrosinase inhibitor for the topical treatment of hyperpigmentation
Authors: Kolbe L. , Mann T. , Gerwat W. , Batzer J. , Ahlheit S. , Scherner C. , Wenck H. , Stäb F.
Published: December 2012

Background  Hyperpigmentary disorders like melasma, actinic and senile lentigines are a major cosmetic concern. Therefore, many topical products are available, containing various active ingredients aiming to reduce melanin production and distribution. The most prominent target for inhibitors of hyperpigmentation is tyrosinase, the key regulator of melanin production. Many inhibitors of tyrosinase are described in the literature; however, most of them lack clinical efficacy.

Methods  We were interested in evaluating the inhibition of skin pigmentation by well‐known compounds with skin‐whitening activity like hydroquinone, arbutin, kojic acid and 4‐n‐butylresorcinol. We compared the inhibition of human tyrosinase activity in a biochemical assay as well as inhibition of melanin production in MelanoDerm™ skin model culture. For some compounds, the in vivo efficacy was tested in clinical studies.

Results  Arbutin and hydroquinone only weakly inhibit human tyrosinase with a half maximal inhibitory concentration (IC50) in the millimolar range. Kojic acid is 10 times more potent with an IC50 of approximately 500 μmol/L. However, by far the most potent inhibitor of human tyrosinase is 4‐n‐butylresorcinol with an IC50 of 21 μmol/L. In artificial skin models, arbutin was least active with an IC50 for inhibition of melanin production > 5000 μmol/L. Kojic acid inhibited with an IC50 > 400 μmol/L. Interestingly, hydroquinone inhibited melanin production in MelanoDerms with an IC50 below 40 μmol/L, probably due to a mechanism different from tyrosinase inhibition. Again, 4‐n‐butylresorcinol was the most potent inhibitor with an IC50 of 13.5 μmol/L. In vivo efficacy of 4‐n‐butyl‐resorcinol was confirmed in clinical studies. Subjects with age spots on the forearm treated twice daily two age spots with a formula containing 4‐n‐butylresorcinol and two control age spots with the corresponding vehicle. Within 8 weeks, 4‐n‐butylresorcinol reduced visibly the appearance of age spots, while the control spots showed no improvement. A second study showed that 4‐butylresorcinol was more effective than 4‐hexylresorcinol and 4‐phenylethylresorcinol.

Conclusion  The present in vitro and in vivo data prove the high inhibitory capacity of 4‐n‐butylresorcinol on human tyrosinase activity, exceeding by far the potency of hydroquinone, arbutin and kojic acid. The resulting clinical improvement of skin hyperpigmentations reveals 4‐n‐butylresorcinol as a very valuable active compound for the management of pigmentation disorders.
Trypanosomatid Pin1‐Type Peptidyl‐Prolyl Isomerase Is Cytosolic and Not Essential for Cell Proliferation
Authors: Erben Esteban D. , Nardelli Sheila C. , de Jesus Teresa C. L. , Schenkman Sergio , Tellez‐Iñon Maria T.
Published: December 2012

Pin1‐type peptidyl‐prolyl cis/trans isomerases (PPIases) isomerise the peptide bond of specific phosphorylated (Ser/Thr)‐Pro residues, regulating various cellular events. Previously, we reported a Pin1‐type PPIase in Trypanosoma cruzi, but little is known about its function and subcellular localization. Immunofluorescence analysis revealed that in contrast with Pin1‐like proteins from diverse organisms, TcPin1 mainly localized in the cytoplasm and was excluded from the nuclei. In addition, RNAi‐mediated downregulation of TbPin1 in Trypanosoma brucei did not abolish cell proliferation. Using yeast two‐hybrid assay, we identified a MORN domain‐containing protein as putative Pin1‐binding partners. These data suggest that Pin1‐mediated signaling mechanism plays a different role in protozoan parasites.
A 24‐h a la carte food service as support for patients at nutritional risk: a pilot study
Authors: Munk T. , Seidelin W. , Rosenbom E. , Nielsen A. L. , Klausen T. W. , Nielsen M. A. , Thomsen T.
Published: December 2012

Background

Undernutrition and insufficient energy and protein intake is a common problem in hospitalised patients. The aim of this pilot study was to investigate whether a novel hospital menu would be an effective strategy for increasing nutritional intake in patients at nutritional risk.

Methods

A historically controlled intervention pilot study was conducted. Forty patients at nutritional risk were offered a novel hospital menu as a supplement to the ordinary hospital menu. The menu consisted of 36 naturally energy‐enriched small dishes served on demand 24 h a day. Energy and protein intake were calculated as the mean over a period of 3 days.

Results

No significant difference in energy and protein intake was observed between the groups; however, a significant (P = 0.001) time gradient in total energy intake was observed in the intervention group. Moreover, a significant (P = 0.03) time gradient in energy intake received from the novel menu was observed. The dishes from the novel menu were mainly ordered from 11.00 h to 14.00 h and from 17.00 h to 18.00 h.

Conclusions

No overall significant differences in energy and protein intake between the groups were found. However, the present pilot study revealed a significant time gradient in total energy intake (P = 0.001) and in energy intake from the novel menu (P = 0.03). This indicates the need to include a run‐in period when investigating novel hospital menus as a support for patients at nutritional risk. Additionally, food service, available 24 h a day, appears to be unnecessary.
The Arabidopsis Anaphase‐Promoting Complex/Cyclosome Subunit 1 is Critical for Both Female Gametogenesis and EmbryogenesisF
Authors: Wang Yanbing , Hou Yingnan , Gu Hongya , Kang Dingming , Chen Zhang‐Liang , Liu Jingjing , Qu Li‐Jia
Published: December 2012

Anaphase‐promoting complex/cyclosome (APC/C), a multisubunit E3 ligase, plays a critical role in cell cycle control, but the functional characterization of each subunit has not yet been completed. To investigate the function of APC1 in Arabidopsis, we analyzed four mutant alleles of APC1, and found that mutation in APC1 resulted in significantly reduced plant fertility, accumulation of cyclin B, and disrupted auxin distribution in embryos. The three mutant alleles apc1–1, apc1–2 and apc1–3 shared variable defects in female gametogenesis including degradation, abnormal nuclear number, and disrupted polarity of nuclei in the embryo sac as well as in embryogenesis, in which embryos were arrested at multiple stages. All of these defects are similar to those previously identified in apc4. The mutant apc1–4, in which the T‐DNA was inserted after the transmembrane domain at the C‐terminus, showed much more severe phenotypes; that is, most of the ovules were arrested at the one‐nucleate female gametophyte stage (stage FG1). In the apc1 apc4 double mutants, the fertility was further reduced by one‐third in apc1–1/+ apc4–1/+, and in some cases no ovules even survived in siliques of apc1–4/+ apc4–1/+. Our data thus suggest that APC1, an essential component of APC/C, plays a synergistic role with APC4 both in female gametogenesis and in embryogenesis.
Cullin‐RING Ubiquitin Ligase Family in Plant Abiotic Stress PathwaysF
Authors: Guo Liquan , Nezames Cynthia D. , Sheng Lianxi , Deng Xingwang , Wei Ning
Published: December 2012

The ubiquitin‐proteasome system is a key mechanism that plants use to generate adaptive responses in coping with various environmental stresses. Cullin‐RING (CRL) complexes represent a predominant group of ubiquitin E3 ligases in this system. In this review, we focus on the CRL E3s that have been implicated in abiotic stress signaling pathways in Arabidopsis. By comparing and analyzing these cases, we hope to gain a better understanding on how CRL complexes work under various settings in an attempt to decipher the clues about the regulatory mechanism of CRL E3s.

image

[ Ning Wei (Corresponding author)]
Risk assessment and management approaches on mental health units
Authors: Woods P.
Published: December 2012

Accessible summary

The study aimed to understand risk assessment and management approaches on a number of mental health units.

Mental health professionals have a number of choices to make when considering risk assessment.

Participants were mainly using a clinical approach to risk assessment, which is affected by their own skill level.

It is important to consider including more structured approaches to risk assessment, as well as education and training, and client participation.

This exploratory and descriptive study took place in one Canadian province. The study aimed to: (1) to identify and describe the nature and extent of current risk assessment and management approaches used in the adult inpatient mental health and forensic units; and (2) to identify good practice and shortfalls in the nature and extent of the approaches currently utilized. Data were collected from 48 participants through nine focus groups. Participants reported that they used a clinical approach to risk assessment. They had also not considered risk assessment and management as a proactive structured process. Education and training was also limited and skills were developed over time through practice. Five keys issues are discussed as important: reliance on clinical judgement alone is not the best choice to make; the need to consider risk as a whole concept; risk management being more reactive than proactive; education and training; and client involvement in risk assessment.
Ethical Aspects of Sexual Medicine. Internet, Vibrators, and Other Sex Aids: Toys or Therapeutic Instruments?
Authors: Jannini Emmanuele A. , Limoncin Erika , Ciocca Giacomo , Buehler Stephanie , Krychman Michael
Published: December 2012

Introduction

Sexual health is the result of a complex interplay between social, relational, intrapsychic, and medical aspects. Sexual health care professionals (SHCP) may face several ethical issues. Some SHCP prescribe Internet pornography for both diagnosis and therapy and some others directly sell vibrators and sex aids in their offices.

Methods

Five scientists, with different perspectives, debate the ethical aspects in the clinical practice of the SHCP.

Main Outcome Measure

To give to the Journal of Sexual Medicine’s reader enough data to form her/his own opinion on an important ethical topic.

Results

Expert #1, who is Controversy’s Section Editor, together with two coworkers, expert psycho-sexologists, reviews data from literature regarding the use of the Internet in the SHCP. Expert #2 argues that licensed professionals, who treat sexual problems, should not sell sexual aids such as vibrators, lubricants, erotica, and instructional DVDs to their clients. On the other hand, Expert #3 is in favor of the possibility, for the patient, to directly purchase sexual aids from the SHCP in order to avoid embarrassment, confusion, and non-adherence to treatment.

Conclusion

Evidence and intelligence would suggest that both the Internet (in selected subjects) and the vibrators (in the correct clinical setting), with the due efforts in counseling the patients and tailoring their therapy, are not-harmful, excellent tools in promoting sexual health.
Use of Epothilone B (Patupilone) in Refractory Lymphoma and Advanced Solid Tumors in Dogs
Authors: Meier V. , Geigy C. , Grosse N. , McSheehy P. , Rohrer Bley C.
Published: December 2012

Background

The epothilones are microtubule‐stabilizing agents with promising antitumor effect in refractory and metastatic tumors in humans. The toxicity profile is considered more favorable than in taxanes. The safety of epothilone B (patupilone) has not been evaluated in tumor‐bearing dogs.

Objectives

To evaluate the inhibition of proliferation in canine tumor cells after patupilone treatment. To assess toxicity profile and maximally tolerated dose of patupilone in dogs with refractory tumors.

Animals

Twenty client‐owned dogs with various malignancies.

Methods

Prospective clinical study. The inhibition of proliferation was assessed with a proliferation assay in vitro in canine hemangiosarcoma and lymphoma cell lines. Dogs received patupilone IV once a week for 2 treatments (= 1 treatment cycle). Dose was escalated with 3 dogs per cohort and 20% increments. Adverse effects were graded accor‐ding to the VCOG‐CTCAE v1.0.

Results

Both canine cell lines were sensitive to patupilone with approximately 50% decrease in proliferative activity at 0.2–1 nM. In vivo, dose‐limiting adverse effects occurred at 3.3 mg/m2; main adverse effects were diarrhea, anorexia, vomiting, and nausea. Neither neutropenia nor peripheral neuropathy was observed. Maximally tolerated dose for 2 patupilone administrations once weekly IV is 2.76 mg/m2. Three per 11 dogs receiving more than 1 treatment cycle showed partial remission in the short period of observation.

Conclusions and Clinical Importance

Canine tumor cells show inhibition of proliferation to patupilone in vitro. Clinically, a dose of 2.76 mg/m2 IV is well tolerated in dogs with spontaneously occurring tumors.
Invasion genetics of the introduced black rat (Rattus rattus) in Senegal, West Africa
Authors: Konečný Adam , Estoup Arnaud , Duplantier Jean‐Marc , Bryja Josef , Bâ Khalilou , Galan Maxime , Tatard Caroline , Cosson Jean‐Francois
Published: December 2012

An understanding of the evolutionary history and dynamics of invasive species is required for the construction of predictive models of future spread and the design of biological management measures. The black rat (Rattus rattus) is a major vertebrate invader with a worldwide distribution. Despite the severe ecological, economic and health impacts of this species, its evolutionary history has been little studied. We carried out extensive specimen sampling in Senegal, West Africa, and used microsatellite markers to describe the pattern and processes of invasion in this large continental area. The genetic data obtained were combined with historical knowledge concerning the presence of this species in Senegal. Data were analysed by a combination of Bayesian clustering and approximate Bayesian computation methods. The invasion pathways closely paralleled the history of human trade routes in Senegal. In several places, we detected the occurrence of multiple introductions from genetically different sources. Long‐distance migration between towns and villages was also observed. Our findings suggest that genetic bottlenecks and admixture have played a major role in shaping the genetics of invasive black rats. These two processes may generate genetic novelty and favour rapid evolution along the invasion pathways.
Historical introgression and the persistence of ghost alleles in the intermediate horseshoe bat (Rhinolophus affinis)
Authors: Mao Xiuguang , He Guimei , Hua Panyu , Jones Gareth , Zhang Shuyi , Rossiter Stephen J.
Published: December 2012

Phylogenetic conflicts between genetic markers can help to disentangle complex histories of phylogeography and introgression among taxa. We previously proposed that the Chinese mainland subspecies of the intermediate horseshoe bat Rhinolophus affinis himalayanus colonized Hainan Island to form the subspecies R. a. hainanus. Subsequent recolonization of the mainland formed a third taxon, R. a macrurus, and a secondary contact zone with the ancestral himalayanus. To test for historical and recurrent genetic exchange between these mainland subspecies, we sampled populations of each from two parapatric zones and undertook analyses using one mtDNA marker, three nuclear genes and 14 microsatellites. Nuclear DNA, echolocation call frequencies and morphological data all recovered two taxa; however, a mtDNA phylogeny revealed two himalayanus clades, of which one clustered with macrurus, as well as some shared or related mtDNA haplotypes in eastern populations. Isolation‐with‐migration (IM) models suggested some mtDNA gene flow from macrurus to himalayanus. However, strong population structure in himalayanus raises the possibility that macrurus captured mtDNA from a coastal population of himalayanus that has since become rare or extinct. To reconcile these two sets of results, we suggest that the IM estimates might reflect historical mtDNA gene flow among populations of himalayanus, before mtDNA was subsequently captured by macrurus. Finally, microsatellite‐based ABC analyses supported the island origin of macrurus; however, mtDNA‐based ABC analyses suggest this taxon might have evolved on the mainland. Our findings highlight the importance of understanding population history and structure for interpreting hybridization and introgression events.
Biomechanical analysis of the herringbone technique as employed by elite cross‐country skiers
Authors: Andersson E. , Stöggl T. , Pellegrini B. , Sandbakk Ø. , Ettema G. , Holmberg H.‐C.
Published: December 2012

This investigation was designed to analyse the kinematics and kinetics of cross‐country skiing at different velocities with the herringbone technique on a steep incline. Eleven elite male cross‐country skiers performed this technique at maximal, high, and moderate velocities on a snow‐covered 15° incline. They positioned their skis laterally (25 to 30°) with a slight inside tilt and planted their poles laterally (8 to 12°) with most leg thrust force exerted on the inside forefoot. Although 77% of the total propulsive force was generated by the legs, the ratio between propulsive and total force was approximately fourfold higher for the poles. The cycle rate increased with velocity (1.20 to 1.60 Hz), whereas the cycle length increased from moderate up to high velocity, but then remained the same at maximal velocity (2.0 to 2.3 m). In conclusion, with the herringbone technique, the skis were angled laterally without gliding, with the forces distributed mainly on the inside forefoot to enable grip for propulsion. The skiers utilized high cycle rates with major propulsion by the legs, highlighting the importance of high peak and rapid generation of leg forces.
Reduction maps and minimal model theory
Authors: Gongyo Yoshinori , Lehmann Brian
Published: December 2012

We use reduction maps to study the minimal model program. Our main result is that the existence of a good minimal model for a Kawamata log terminal pair (X,Δ) can be detected on a birational model of the base of the (KX+Δ)-trivial reduction map. We then interpret the main conjectures of the minimal model program as a natural statement about the existence of curves on X.
A fiber dimension theorem for essential and canonical dimension
Authors: Lötscher Roland
Published: December 2012

The well-known fiber dimension theorem in algebraic geometry says that for every morphismf:X→Yof integral schemes of finite type the dimension of every fiber offis at least dimX−dimY. This has recently been generalized by Brosnan, Reichstein and Vistoli to certain morphisms of algebraic stacksf:𝒳→𝒴, where the usual dimension is replaced by essential dimension. We will prove a general version for morphisms of categories fibered in groupoids. Moreover, we will prove a variant of this theorem, where essential dimension and canonical dimension are linked. These results let us relate essential dimension to canonical dimension of algebraic groups. In particular, using the recent computation of the essential dimension of algebraic tori by MacDonald, Meyer, Reichstein and the author, we establish a lower bound on the canonical dimension of algebraic tori.
Creating a Space for Innovative Device Development
Authors: McMurry-Heath Michelle , Hamburg Margaret A.
Published: December 2012

FDA announces a partnership—the Medical Device Innovation Consortium—to advance regulatory science in the medical technology arena.
In Vivo
Bioluminescence Imaging To Evaluate Systemic and Topical Antibiotics against Community-Acquired Methicillin-Resistant Staphylococcus aureus-Infected Skin Wounds in Mice
Authors: Guo Yi , Ramos Romela Irene , Cho John S. , Donegan Niles P. , Cheung Ambrose L. , Miller Lloyd S.
Published: December 2012

Community-acquired methicillin-resistant
Staphylococcus aureus
(CA-MRSA) frequently causes skin and soft tissue infections, including impetigo, cellulitis, folliculitis, and infected wounds and ulcers. Uncomplicated CA-MRSA skin infections are typically managed in an outpatient setting with oral and topical antibiotics and/or incision and drainage, whereas complicated skin infections often require hospitalization, intravenous antibiotics, and sometimes surgery. The aim of this study was to develop a mouse model of CA-MRSA wound infection to compare the efficacy of commonly used systemic and topical antibiotics. A bioluminescent USA300 CA-MRSA strain was inoculated into full-thickness scalpel wounds on the backs of mice and digital photography/image analysis and
in vivo
bioluminescence imaging were used to measure wound healing and the bacterial burden. Subcutaneous vancomycin, daptomycin, and linezolid similarly reduced the lesion sizes and bacterial burden. Oral linezolid, clindamycin, and doxycycline all decreased the lesion sizes and bacterial burden. Oral trimethoprim-sulfamethoxazole decreased the bacterial burden but did not decrease the lesion size. Topical mupirocin and retapamulin ointments both reduced the bacterial burden. However, the petrolatum vehicle ointment for retapamulin, but not the polyethylene glycol vehicle ointment for mupirocin, promoted wound healing and initially increased the bacterial burden. Finally, in type 2 diabetic mice, subcutaneous linezolid and daptomycin had the most rapid therapeutic effect compared with vancomycin. Taken together, this mouse model of CA-MRSA wound infection, which utilizes
in vivo
bioluminescence imaging to monitor the bacterial burden, represents an alternative method to evaluate the preclinical
in vivo
efficacy of systemic and topical antimicrobial agents.
Putative Compensatory Mutations in the
rpoC
Gene of Rifampin-Resistant Mycobacterium tuberculosis Are Associated with Ongoing Transmission
Authors: de Vos M. , Müller B. , Borrell S. , Black P. A. , van Helden P. D. , Warren R. M. , Gagneux S. , Victor T. C.
Published: December 2012

Rifampin resistance in clinical isolates of
Mycobacterium tuberculosis
arises primarily through the selection of bacterial variants harboring mutations in the 81-bp rifampin resistance-determining region of the
rpoB
gene. While these mutations were shown to infer a fitness cost in the absence of antibiotic pressure, compensatory mutations in
rpoA
and
rpoC
were identified which restore the fitness of rifampin-resistant bacteria carrying mutations in
rpoB
. To investigate the epidemiological relevance of these compensatory mutations, we analyzed 286 drug-resistant and 54 drug-susceptible clinical
M. tuberculosis
isolates from the Western Cape, South Africa, a high-incidence setting of multidrug-resistant tuberculosis. Sequencing of a portion of the RpoA-RpoC interaction region of the
rpoC
gene revealed that 23.5% of all rifampin-resistant isolates tested carried a nonsynonymous mutation in this region. These putative compensatory mutations in
rpoC
were associated with transmission, as 30.8% of all rifampin-resistant isolates with an IS
6110
restriction fragment length polymorphism (RFLP) pattern belonging to a recognized RFLP cluster harbored putative
rpoC
mutations. Such mutations were present in only 9.4% of rifampin-resistant isolates with unique RFLP patterns (
P
< 0.01). Moreover, these putative compensatory mutations were associated with specific strain genotypes and the
rpoB
S531L rifampin resistance mutation. Among isolates harboring this
rpoB
mutation, 44.1% also harbored
rpoC
mutations, while only 4.1% of the isolates with other
rpoB
mutations exhibited mutations in
rpoC
(
P
< 0.001). Our study supports a role for
rpoC
mutations in the transmission of multidrug-resistant tuberculosis and illustrates how epistatic interactions between drug resistance-conferring mutations, compensatory mutations, and different strain genetic backgrounds might influence compensatory evolution in drug-resistant
M. tuberculosis
.
Reduced Artemisinin Susceptibility of Plasmodium falciparum Ring Stages in Western Cambodia
Authors: Witkowski Benoit , Khim Nimol , Chim Pheaktra , Kim Saorin , Ke Sopheakvatey , Kloeung Nimol , Chy Sophy , Duong Socheat , Leang Rithea , Ringwald Pascal , Dondorp Arjen M. , Tripura Rupam , Benoit-Vical Françoise , Berry Antoine , Gorgette Olivier , Ariey Frédéric , Barale Jean-Christophe , Mercereau-Puijalon Odile , Menard Didier
Published: December 2012

The declining efficacy of artemisinin derivatives against
Plasmodium falciparum
in western Cambodia is a major concern. The knowledge gap in the understanding of the mechanisms involved hampers designing monitoring tools. Here, we culture-adapted 20 isolates from Pailin and Ratanakiri (areas of artemisinin resistance and susceptibility in western and eastern Cambodia, respectively) and studied their
in vitro
response to dihydroartemisinin. No significant difference between the two sets of isolates was observed in the classical isotopic test. However, a 6-h pulse exposure to 700 nM dihydroartemisinin (ring-stage survival assay -RSA]) revealed a clear-cut geographic dichotomy. The survival rate of exposed ring-stage parasites (ring stages) was 17-fold higher in isolates from Pailin (median, 13.5%) than in those from Ratanakiri (median, 0.8%), while exposed mature stages were equally and highly susceptible (0.6% and 0.7%, respectively). Ring stages survived drug exposure by cell cycle arrest and resumed growth upon drug withdrawal. The reduced susceptibility to artemisinin in Pailin appears to be associated with an altered
in vitro
phenotype of ring stages from Pailin in the RSA.
Daptomycin Pharmacokinetics and Pharmacodynamics in a Pooled Sample of Patients Receiving Thrice-Weekly Hemodialysis
Authors: Butterfield Jill M. , Mueller Bruce A. , Patel Nimish , Cardone Katie E. , Grabe Darren W. , Salama Noha N. , Lodise Thomas P.
Published: December 2012

While the pharmacokinetic (PK) properties of daptomycin in hemodialysis (HD) patients have been evaluated previously by three groups, resultant dosing recommendations have varied. To address this clinical conundrum, this study combined concentration-time data from these PK evaluations and derived uniform dosing recommendations among patients on HD receiving daptomycin. A two-compartment model with separate HD and non-HD clearance terms was fit to the PK data from these studies by using BigNPAG. Embedded with PK parameters from the population PK analysis, 5,000-subject Monte Carlo simulations (MCS) were performed to identify HD dosing schemes that provided efficacy (cumulative and daily area under the concentration-time curve [AUC] values) and toxicity (trough concentrations of ≥24.3 mg/liter) profiles comparable to those from simulations employing the daptomycin PK model derived from the
Staphylococcus aureus
bacteremia–infective endocarditis (SAB-IE) study. Separate HD dosing schemes were sought for the two weekly interdialytic periods (48 and 72 h). For the 48-h interdialytic period, intra- and post-HD dosing provided the most isometric cumulative and daily AUCs. For the 72-h interdialytic period, all HD dosing schemes provided noncumulative AUC values from 48 to 72 h (AUC
48–72
) that were <50% of the SAB-IE AUC
48–72
values. Increasing the parent dose by 50% intra- or post-HD provided comparable AUC
48–72
values, while maintaining acceptable trough concentration (
C
min
) values. When efficacy and toxicity profiles were evaluated for each individual study, higher probabilities for
C
min
reaching ≥24.3 mg/liter were observed in one of the three studies. Given the high probability of
C
min
being ≥24.3 mg/liter in one of the three studies, more intensive creatine phosphokinase (CPK) monitoring may be warranted in HD patients receiving daptomycin.
Crystal Structures of Pseudomonas aeruginosa GIM-1: Active-Site Plasticity in Metallo-β-Lactamases
Authors: Borra Pardha Saradhi , Samuelsen Ørjan , Spencer James , Walsh Timothy R. , Lorentzen Marit Sjo , Leiros Hanna-Kirsti S.
Published: December 2012

Metallo-β-lactamases (MBLs) have rapidly disseminated worldwide among clinically important Gram-negative bacteria and have challenged the therapeutic use of β-lactam antibiotics, particularly carbapenems. The
bla
GIM-1
gene, encoding one such enzyme, was first discovered in a
Pseudomonas aeruginosa
isolate from 2002 and has more recently been reported in
Enterobacteriaceae
. Here, we present crystal structures of GIM-1 in the apo-zinc (metal-free), mono-zinc (where Cys221 was found to be oxidized), and di-zinc forms, providing nine independently refined views of the enzyme. GIM-1 is distinguished from related MBLs in possessing a narrower active-site groove defined by aromatic side chains (Trp228 and Tyr233) at positions normally occupied by hydrophilic residues in other MBLs. Our structures reveal considerable flexibility in two loops (loop 1, residues 60 to 66; loop 2, residues 223 to 242) adjacent to the active site, with open and closed conformations defined by alternative hydrogen-bonding patterns involving Trp228. We suggest that this capacity for rearrangement permits GIM-1 to hydrolyze a wide range of β-lactams in spite of possessing a more constrained active site. Our results highlight the structural diversity within the MBL enzyme family.
Epithelial Cells Augment Barrier Function via Activation of the Toll-Like Receptor 2/Phosphatidylinositol 3-Kinase Pathway upon Recognition of Salmonella enterica Serovar Typhimurium Curli Fibrils in the Gut
Authors: Oppong Gertrude O. , Rapsinski Glenn J. , Newman Tiffanny N. , Nishimori Jessalyn H. , Biesecker Steven G. , Tükel Çagla
Published: December 2012

Curli fibrils, the best-characterized functional bacterial amyloids, are an important component of enterobacterial biofilms. We have previously shown that curli fibrils are recognized by the Toll-like receptor 2 (TLR2)/TLR1 heterodimer complex. Utilizing polarized T-84 cells, an intestinal epithelial cell line derived from colon carcinoma grown on semipermeable tissue culture inserts, we determined that infection with aSalmonella entericaserovar TyphimuriumcsgBAmutant, which does not express curli, resulted in an increase in intestinal barrier permeability and an increase in bacterial translocation compared to infection with curliated wild-typeS. Typhimurium. When the TLR2 downstream signaling molecule phosphatidylinositol 3-kinase (PI3K) was blocked using wortmannin or LY294002, the difference in disruption of the intestinal epithelium and bacterial translocation was no longer observed. Additionally, disruption of polarized T-84 cells treated basolaterally with the TLR5 ligand flagellin was prevented when the polarized cells were simultaneously treated with the synthetic TLR2/TLR1 ligand Pam3CSK4or with purified curli fibrils in the apical compartment. Similar toin vitroobservations, C57BL/6 mice infected with thecsgBAmutant suffered increased disruption of the intestinal epithelium and therefore greater dissemination of the bacteria to the mesenteric lymph nodes than mice infected with wild-typeS. Typhimurium. The differences in disruption of the intestinal epithelium and bacterial dissemination in the mice infected withcsgBAmutant or wild-typeS. Typhimurium were not apparent in TLR2-deficient mice. Overall, these studies report for the first time that activation of the TLR2/PI3K pathway by microbial amyloids plays a critical role in regulating the intestinal epithelial barrier as well as monitoring bacterial translocation during infection.
Tannic Acid Inhibits Staphylococcus aureus Surface Colonization in an IsaA-Dependent Manner
Authors: Payne David E. , Martin Nicholas R. , Parzych Katherine R. , Rickard Alex H. , Underwood Adam , Boles Blaise R.
Published: December 2012

Staphylococcus aureus
is a human commensal and pathogen that is capable of forming biofilms on a variety of host tissues and implanted medical devices. Biofilm-associated infections resist antimicrobial chemotherapy and attack from the host immune system, making these infections particularly difficult to treat. In order to gain insight into environmental conditions that influence
S. aureus
biofilm development, we screened a library of small molecules for the ability to inhibit
S. aureus
biofilm formation. This led to the finding that the polyphenolic compound tannic acid inhibits
S. aureus
biofilm formation in multiple biofilm models without inhibiting bacterial growth. We present evidence that tannic acid inhibits
S. aureus
biofilm formation via a mechanism dependent upon the putative transglycosylase IsaA. Tannic acid did not inhibit biofilm formation of an
isaA
mutant. Overexpression of wild-type IsaA inhibited biofilm formation, whereas overexpression of a catalytically dead IsaA had no effect. Tannin-containing drinks like tea have been found to reduce methicillin-resistant
S. aureus
nasal colonization. We found that black tea inhibited
S. aureus
biofilm development and that an
isaA
mutant resisted this inhibition. Antibiofilm activity was eliminated from tea when milk was added to precipitate the tannic acid. Finally, we developed a rodent model for
S. aureus
throat colonization and found that tea consumption reduced
S. aureus
throat colonization via an
isaA
-dependent mechanism. These findings provide insight into a molecular mechanism by which commonly consumed polyphenolic compounds, such as tannins, influence
S. aureus
surface colonization.
Site of Isolation Determines Biofilm Formation and Virulence Phenotypes of Streptococcus pneumoniae Serotype 3 Clinical Isolates
Authors: Trappetti Claudia , van der Maten Erika , Amin Zarina , Potter Adam J. , Chen Austen Y. , van Mourik Paula M. , Lawrence Andrew J. , Paton Adrienne W. , Paton James C.
Published: December 2012

Streptococcus pneumoniae
is a diverse species causing invasive as well as localized infections that result in massive global morbidity and mortality. Strains vary markedly in pathogenic potential, but the molecular basis is obscured by the diversity and plasticity of the pneumococcal genome. In the present study,
S. pneumoniae
serotype 3 blood (
n
= 12) or ear (
n
= 13) isolates were multilocus sequence typed (MLST) and assessed for biofilm formation and virulence phenotype. Blood and ear isolates exhibited similar MLST distributions but differed markedly in phenotype. Blood isolates formed robust biofilms only at pH 7.4, which were enhanced in Fe(III)-supplemented medium. Conversely, ear isolates formed biofilms only at pH 6.8, and Fe(III) was inhibitory. Biofilm formation paralleled
luxS
expression and genetic competence. In a mouse intranasal challenge model, blood isolates did not stably colonize the nasopharynx but spread to the blood; none spread to the ear. Ear isolates colonized the nasopharynx at higher levels and also spread to the ear compartment in a significant proportion of animals; none caused bacteremia. Thus, pneumococci of the same serotype and MLST exhibit distinct phenotypes in accordance with clinical site of isolation, indicative of stable niche adaptation within a clonal lineage.
Severe obstructive sleep apnoea due to adenotonsillar hypertrophy after liver transplantation
Authors: Mulla Omar , Bajaj Yogesh , Knight Lindsey
Published: December 2012

Epstein-Barr virus-related adenotonsillar hypertrophy is a precursor to post-transplantation lymphoproliferative disorder. We report a case of a 4-year-old child with severe obstructive sleep apnoea, who had liver transplantation at the age of 7 months. She had gross lymphoid hypertrophy in the oropharynx and supraglottis. We performed an adenotonsillectomy and aryepiglottoplasty which improved her symptoms. We emphasise the importance to consider the diagnosis of post-transplantation lymphoproliferative disorder in post-transplantation immunosuppressed patients who present with adenotonsillar hypertrophy.
Floral nectar production in Helleborus foetidus: an ultrastructural study
Authors: Vesprini J.L. , Pacini E. , Nepi M.
Published: December 2012

The floral nectaries of Helleborus foetidus L. were studied using scanning and transmission electron microscopy, as well as light microscopy. Nectaries are tubular and consist of an external epidermis, a photosynthesizing parenchyma, large branches of vascular tissue, a nectar-producing parenchyma, and an internal epidermis. The external epidermis is characterized by thick outer walls and a thin cuticle. Cells of the photosynthesizing parenchyma are characterized by chloroamyloplasts. The nectar-producing parenchyma consists of small cells with lobed nucleus, several small vacuoles, and numerous undifferentiated elongated plastids. These cells contain lipid bodies, Golgi membranes, and rough endoplasmic reticulum and are connected by numerous plasmodesmata. Parenchyma cells around sieve elements contain some amyloplasts. The outer cell wall of the internal epidermis displays a central thinned area containing a depression. The cuticle is very thick with amorphous structure, especially evident in its proximal part. Secretion takes place only in the inner basal region of the nectary cup. The surface of the internal epidermis is devoid of secreting structures. Nectar is released by fracture of the cuticle and underlying cell wall; however, epidermal cell death is not apoptotic. This holocrine secretion is coupled with a more common merocrine secretion through which nectar accumulates in subcuticular spaces. This combined secretion mode produces an enriched “nectar soup” crucial for interactions with pollinators and yeasts during winter flowering.
Connection development and in-plane response of glass fiber reinforced polymer sandwich panels with reinforced cores
Authors: Dawood Mina , Peirick Leo
Published: December 2012

This paper presents the findings of an experimental research project that was conducted in two phases to study the behavior of glass fiber reinforced polymer (GFRP) sandwich panels with reinforced cores under in-plane loading conditions. The tested panels consisted of two GFRP face skins separated by a polymeric foam core. The foam core was reinforced with different configurations of through-thickness fiber insertions and through-thickness GFRP web skins. In the first phase the performance of three different types of structural connections was tested — namely, bolted, bonded, and so-called enhanced bolted connections. The findings indicate that bolted connections to thinner and more flexible panels exhibited lower strength and a higher degree of nonlinear behavior compared with the bonded connections to the same panels. In contrast, the bolted connections to thicker and stiffer panels were generally stronger and stiffer than their bonded counterparts. The findings further indicate that the ultimate strength of the connections can be increased by up to 26% by bonding a steel reinforcing plate to the face skins of the panel prior to bolting. In the second phase three full-scale sandwich panels (1400 mm × 1400 mm) with different panel configurations were tested under proportional, biaxial, in-plane loading. The applied loads were selected to simulate the in-plane loading conditions in sandwich panels that are subjected primarily to in-plane loads, such as webs of deep beams and shear walls in lightweight structures. The full-field strains and displacements of the panels were measured using a digital image correlation-based (DIC) non-contact measurement system. The findings indicate that the through-thickness core reinforcements effectively prevented localized buckling, debonding, and separation of the panels’ face skins. The findings also demonstrated that slender panels exhibit shear–compression buckling failures, whereas less slender panels exhibit shear–tension rupture failures.
Infection cycle ofSalmonella entericaserovar Enteritidis in latent carrier mice1The work was carried out at the Microbial Biotechnology Laboratory of Universidade Estadual de Santa Cruz, Ilhéus, Bahia State, Brazil.
Authors: Maciel Bianca Mendes , Sriranganathan Nammalwar , Romano Carla Cristina , Santos Thalis Ferreira dos , Dias João Carlos Teixeira , Gross Eduardo , Rezende Rachel Passos
Published: December 2012

This work reports the distribution of an oral dose of Salmonella enterica serovar Enteritidis (SE) in C57Bl/6-Bcgr mice, to study its pathogenesis in a latent carrier animal. Mice orally inoculated with a high dose of SE developed a latent infection characterized by the absence of clinical symptoms in which the cecum is functioning as a “strategic site” of SE proliferation, releasing bacteria into feces intermittently over the 4-week study. A sequence of disruptions occurred in the small intestine at 1 day postinculation (PI). The microvilli exhibited different degrees of degeneration, which were reversible as the cells became vacuolated. From 2 days PI, SE was detected in the mononuclear phagocytic system, and an exponential growth of the remaining bacteria in tissues was observed until 4 days PI. The production of interferon gamma from 3 days PI is restricting the SE growth, and a plateau phase was observed from 4 to 15 days PI. A recurrence of the bacterial growth in tissue occurred from 15 to 28 days PI, especially in the cecum. Increasing our knowledge about the host–pathogen interaction of adapted pathogens with the ability to develop latency is essential for the development of an efficient strategy for Salmonella control.