bluuebunny/crossref_metadata_2025 huggingface dataset:
Employing a teaching module improves patient satisfaction in facial rejuvenation
Authors: Freedman B M , Earley R V , Balakrishnan T P
Published: June 2006

Background and objectives  The purpose of this study was to determine whether a teaching module for facial rejuvenation improved patient satisfaction and enhanced practice growth in a cosmetic surgery office. An educational module was designed to review soft‐tissue anatomy and physiology, treatment options, and outcomes.

Materials and methods  During the initial office consultation, the module was utilized in group A (50 patients) but not in group B (50 patients). Satisfaction surveys were taken from all patients following the consultation. Patients from both groups who scheduled procedures were surveyed following completion of treatment.

Results  The surveys indicated a statistically significant higher level of satisfaction with the consultation, a better understanding of treatment options, and a greater percentage of treatment scheduling in group A patients (P < 0.05). Furthermore, patients in group A who underwent treatment indicated greater satisfaction with treatment outcome when compared to those treated patients in group B (P < 0.05).

Conclusions  We conclude that use of a well‐designed teaching module helps patients better understand the concepts behind facial rejuvenation and leads to increased procedure scheduling and greater patient satisfaction following treatment.
A note on integumental (1→3)(1→6)β‐d‐glucan permeation, using the porcine ear skin model
Authors: Meyer Wilfried , Schönnagel Britta , Fleischer Lutz‐Günther
Published: June 2006

Based on carbohydrate histochemical methods and the porcine ear skin model, the study demonstrates the rapid permeation of (1→3)(1→6)β‐d‐glucans from a cosmetic formulation into the mammalian epidermis.
Treatment of periungual vitiligo with Erbium‐YAG‐laser plus 5‐flurouracil: a left to right comparative study
Authors: Anbar Tag , Westerhof Weite , Abdel‐Rahman Amal , El‐Khayyat Mohamed , El‐Metwally Yasser
Published: June 2006

Despite the multiple treatment modalities available for vitiligo, none of them gives satisfactory results in the periungual type. In this study we tried to explore and evaluate the effects of the combination treatment of erbium:YAG laser resurfacing and topical 5‐flurouracil in periungual vitiligo.

Nine adult patients presenting with periungual vitiligo lesions were included in this prospective left–right comparative study. The desirable inflammation was achieved after a mean of 4.7 days of 5‐flurouracil application. The mean re‐epithelization time in the treatment sessions was 11.3 days. The patients received a mean of 3.4 sessions in a mean duration of 7.6 months. The mean overall response to therapy in the treated group was 47.8% while in the control group it was 1.1% (P < 0.0001). No side effects necessitated the stoppage of treatment.

This study points to the efficacy and safety of this combination in the treatment of periungual vitiligo.
Atopic xerosis: employment of noninvasive biophysical instrumentation for the functional analyses of the mildly abnormal stratum corneum and for the efficacy assessment of skin care products
Authors: Tagami Hachiro , Kobayashi Hiromi , O’goshi Kenichiro , Kikuchi Katsuko
Published: June 2006

The subtle dryness of the skin surrounding the lesions of atopic dermatitis (AD) is called atopic dry skin or atopic xerosis (AX). AX is more susceptible to the development of AD skin lesions under various environmental stimuli than the clinically normal skin of the people who have or have had or will have AD, which might be called normal atopic skin (NAS) that shows no functional differences as compared to the skin of normal individuals. Routine histopathologic studies of AX that involve the invasive procedures of biopsy are not so helpful in clarifying the underlying pathogenesis. Modern, noninvasive biophysical instrumentation provides rich and quantitative information about various functional aspects of skin. The stratum corneum (SC) of AX reveals not only decreased hydration but also mildly impaired barrier function demonstrable as an increase in transepidermal water loss, elevated pH values, and an increased turnover rate of the SC consisting of thick layers of smaller‐sized corneocytes. These data suggest that AX is related to mildly increased epidermal proliferation as a result of the presence of subclinical cutaneous inflammation. Although AX skin does not display any impairment in the recovery of barrier function after physical skin irritation by tape‐stripping, it produces a much more severe, long‐lasting inflammatory response together with a delay in barrier repair after chemical irritation such as that induced by sodium lauryl sulphate. The SC of AX is biochemically characterized by reduction in the amounts of ceramides, especially ceramide I, sebum lipids, and water‐soluble amino acids. None of these changes in SC functions are seen in NAS, which includes not only the normal‐looking skin of AD patients long after regression of all active lesions but also of latent atopic skin such as neonates who later develop AD. This suggests that all of the observed functional as well as biochemical abnormalities of AX are a reflection of subclinical inflammation. The presence of the underlying inflammation in AX also differentiates it from senile xerosis. The mildly impaired SC functions of AX can be improved by daily repeated applications of effective moisturizers, i.e., corneotherapy, which is effective in preventing the exacerbating progression of AX to AD resulting from inadvertent scratching of the skin that facilitates the penetration of environmental allergens into the skin. The biophysical confirmation of such efficacy of moisturizers, including cosmetic bases on the mildly impaired barrier function and decreased water‐holding capacity of the SC of AX, definitely substantiates the importance of skin care for the cosmetic skin problems that affect every individual in the cold and dry season ranging from late autumn to early spring.
Onychomycosis: beyond cosmetic distress
Authors: Lateur Nadine
Published: June 2006

Onychomycosis, or fungal infection of the nail, is the most common nail disease affecting children (although to a lesser extent) as well as adults. The distress it provokes is not only of a cosmetic kind; it may impair the quality of life.

The different clinical types of onychomycosis should be differentiated from similar‐looking nail diseases. As far as therapy is concerned, the appearance of new antifungal drugs in the 1990s makes our job easier, but it does not allow us to cure 100% of the patients. Relapses still exist.

The aim of this article is to help dermatologists achieve a tailor‐made treatment for their patients. The clinical type, the compulsory mycological investigations, the age of the patient, his medical history (drug intake), as well as the use of nail cosmetics, must be considered.
Development of sonic technology for the daily cleansing of the skin
Authors: Akridge Robert E , Pilcher Kenneth A
Published: June 2006

Even though many skin cleansing products are commercially available, the cleansing of the skin is dependent upon the user's diligence, compliance, and technique, which often results in inconsistent cleansing. When the skin is inadequately or excessively cleansed, the skin becomes compromised, sometimes leading to acute or chronic conditions that may require medical attention. A sonic skincare brush was developed to enhance and provide consistent skin cleansing while preventing the skin from becoming compromised. Utilizing a technology previously used to cleanse the oral cavity, the sonic skincare brush is optimized to work with the skin's own elasticity providing rapid oscillatory flexing of the infundibular opening. By oscillating at sonic speed the net result is the inelastic comedones become loosened and detached from the infundibular wall and are then cleared from the acroinfundibulum. Although additional clinical research into the various applications of sonic skin care technology is needed, utilization of sonic technology is now available for effectively and consistently cleansing the skin.
Effects of Family Structure on Children's Use of Ambulatory Visits and Prescription Medications
Authors: Chen Alex Y. , Escarce José J.
Published: June 2006

Objective. To examine the effects of family structure, including number of parents, number of other children, and number and type of other adults, on office visits, emergency room visits, and use of prescription medications by children.

Data Source. The Household Component of the 1996–2001 Medical Expenditure Panel Survey (MEPS).

Study Design. The study consisted of a nationally representative sample of children 0–17 years of age living in single‐mother or two‐parent families. We used negative binomial regression to model office visits and emergency room visits and logistic regression to model the likelihood of prescription medication use. Our analyses adjusted for demographic and socioeconomic characteristics as well as measures of children's health and parental education and child‐rearing experience.

Data Collection/Extraction Method. We combined 1996–2001 MEPS Full Year Consolidated Files and Medical Conditions Files.

Principal Findings. Descriptive data showed that children in single‐mother families had fewer office visits than children in two‐parent families; however, the effect of number of parents in the family on children's office visits or use of prescription medications was completely explained by other explanatory variables. By contrast, children living in families with many other children had fewer total and physician office visits and a lower likelihood of using a prescription medication than children living in families with no other children even after adjusting for other explanatory variables. Children who lived with other adults in addition to their parents also had fewer office visits and a lower likelihood of using a prescription medication than children who lived only with their parents.

Conclusions. Children living in families with many other children or with other adults use less ambulatory care and prescription medications than their peers. Additional research is needed to determine whether these differences in utilization affect children's health.
What's Driving the Downward Trend in Employer‐Sponsored Health Insurance?
Authors: Shen Yu‐Chu , Long Sharon K.
Published: June 2006

Objective. We investigate the factors driving the downward trend in employer sponsored health insurance (ESI) coverage between 1999 and 2002 for low‐ and middle‐income workers, and assess their insurance options in the absence of ESI coverage.

Data. We use the 1999 and 2002 rounds of the National Survey of America's Families (NSAF), supplemented with ESI premiums from the Medical Expenditure Panel Survey, as well as other state‐ and county‐level data from a variety of sources. The sample includes workers between the ages of 19 and 64.

Study Design. We first estimate linear probability models of the probability of having an ESI offer and, for those with an offer, the probability of taking up ESI coverage, using two‐stage least square regression on the 2002 worker sample. We then use Oaxaca–Blinder regression‐based decomposition methods to identify the factors that explain the changes in ESI offer and take‐up between 1999 and 2002.

Principal Findings. We find that while low‐income workers are more likely to be uninsured and are most vulnerable to the loss of ESI coverage, many middle‐income workers are also in a precarious position when faced with the loss of ESI coverage. Many low‐ and middle‐income workers have few coverage options in the absence of ESI. This is particularly problematic for low‐income workers: only 13 percent have a spouse with an ESI offer and the nongroup premium they face increased at a much higher rate than for middle‐income workers. Finally, we find that the drop in ESI offers between 1999 and 2002 was driven largely by changes in nature of the workers' jobs, while the drop in ESI take‐up was driven largely by rising ESI premiums.

Conclusions. Policies that shore up the ESI system are important for both low‐ and middle‐income workers, as both are vulnerable to a loss of insurance coverage in the absence of ESI. Over time, the potential coverage options available to low‐ and middle‐income workers in the absence of ESI have narrowed as nongroup premiums have increased. While public coverage has provided some protection from that increase for low‐income workers, middle‐income workers are much less likely to have access to public protection.
Predictability in Financial Analyst Forecast Errors: Learning or Irrationality?
Authors: MARKOV STANIMIR , TAMAYO ANE
Published: June 2006

In this paper, we propose a rational learning‐based explanation for the predictability in financial analysts' earnings forecast errors documented in prior literature. In particular, we argue that the serial correlation pattern in analysts' quarterly earnings forecast errors is consistent with an environment in which analysts face parameter uncertainty and learn rationally about the parameters over time. Using simulations and real data, we show that the predictability evidence is more consistent with rational learning than with irrationality (fixation on a seasonal random walk model or some other dogmatic belief).
A feasibility study of low‐dose total body irradiation for relapsed canine lymphoma
Authors: Brown E. M. , Ruslander D. M. , Azuma C. , Moore A. S. , Bengtson A. E. , Quesenberry P. J. , Frimberger A. E.
Published: June 2006

Seven client owned dogs with confirmed relapsed lymphoma were enrolled in a prospective feasibility study investigating the effects of low‐dose total body irradiation (LDTBI) delivered in a single 1 Gy fraction. LDTBI for relapsed lymphoma was safe and well tolerated. The only major side‐effect of LDTBI was asymptomatic thrombocytopenia in all dogs. The median platelet nadir was 17 000/μL (range 4000–89 000), which occurred a median of 10 days (range 8–30) post irradiation. Three dogs had short‐term partial responses, two stable disease and two progressive disease (PD). Six dogs were euthanatized for PD, and one dog died while in partial remission. No dogs had clinical complications. Survival analysis was not performed, because the study design did not allow for evaluation of survival time. Larger studies incorporating LDTBI in the induction/consolidation phase of treatment need to be performed to determine the therapeutic efficacy of LDTBI.
Palliative radiotherapy as treatment for non‐resectable soft tissue sarcomas in the dog – a report of 15 cases
Authors: Plavec T. , Kessler M. , Kandel B. , Schwietzer A. , Roleff S.
Published: June 2006

Fifteen dogs with various non‐resectable soft tissue sarcomas were treated with a palliative protocol of Cobalt60radiation. Twelve (80%) of the 15 tumours were fibrosarcomas and haemangiopericytomas. Total tumour radiation dose was 24 Gy, given in three 8 Gy fractions, on days 0, 7, 21 or weekly. Thirteen tumours (87%) responded with stable disease; median time to progression and median survival time were 263 and 332 days, respectively. Radiation toxicity was negligible. The survival and local control with this palliative protocol are almost comparable with curative intent primary radiotherapy.
Working to Make Interdisciplinarity Work: Investing in Communication and Interpersonal Relationships
Authors: Marzano Mariella , Carss David N. , Bell Sandra
Published: June 2006

In this paper, we apply qualitative methodologies to explore the practice of interdisciplinary research. The UK's Rural Economy and Land Use (RELU) Programme aims to advance understanding of the challenges faced by rural areas through funding interdisciplinary research to inform future policy and practice on management choices for the countryside and rural economies. Addressing the challenges faced by rural areas often requires a combination of different perspectives, involving research to address subjects that may lie beyond the skills of individual researchers. An interdisciplinary approach requires the integration of both data/information and the experiences and perspectives of different people (natural/social scientists, local people and policy‐makers). We focus here on the processes involved in making interdisciplinarity work, documenting the experiences, perceptions, ideas and concerns of researchers working in interdisciplinary projects (specifically two EU‐funded projects but also the first wave of RELU projects). A key finding from this research is that interdisciplinarity requires conscious effort, time and resources for the development of interpersonal relationships to enhance effective communication and thus successful collaboration.
Food Choice in an Interdisciplinary Context
Authors: Tiffin Richard , Bruce Traill W. , Mortimer Simon
Published: June 2006

Reform of agricultural policies, notably the continuing elimination of production‐enhancing subsidies, makes it possible for policies to respond to social issues such as the rural environment and health in future. In this paper, we draw on a Rural Economy and Land Use (RELU) research project which is examining the potential for the development of healthy food chains and the implications for human health and the environment. One of the key issues to be addressed is consumers’ willingness to pay for the nutritionally enhanced food products from these new chains, but it is evident that only a partial understanding can be gained from a traditional economics approach. In the paper, we discuss how economists are beginning to incorporate views from other disciplines into their models of consumer choice.
Analysing the Agricultural Costs and Non‐market Benefits of Implementing the Water Framework Directive
Authors: Bateman Ian J. , Brouwer Roy , Davies Helen , Day Brett H. , Deflandre Amelie , Falco Salvatore Di , Georgiou Stavros , Hadley David , Hutchins Michael , Jones Andrew P. , Kay David , Leeks Graham , Lewis Mervyn , Lovett Andrew A. , Neal Colin , Posen Paulette , Rigby Dan , Kerry Turner R.
Published: June 2006

Implementation of the Water Framework Directive (WFD) represents a fundamental change in the management of water in Europe with a requirement that member states ensure ‘good ecological status’ for all water bodies by 2015. Agriculture is expected to bear a major share of WFD implementation costs as it is compelled to reduce the emission of diffuse water pollutants. The research outlined here comprises interdisciplinary modelling of agricultural land use, hydrology and consequent water quality effects to consider both agricultural costs and the non‐market recreational use (and potentially non‐use) values that implementation of the Directive may generate. A theme throughout the research is the spatial distribution of the costs and benefits of WFD implementation, which is addressed through the use of GIS techniques in the modelling of agricultural land use, the integration of land use and hydrological models, and the estimation, aggregation and transfer of the economic value of the benefits.
Managing Food Chain Risks: Integrating Technical and Stakeholder Perspectives on Uncertainty
Authors: Shepherd Richard , Barker Gary , French Simon , Hart Andy , Maule John , Cassidy Angela
Published: June 2006

We explore ways for expressing and communicating uncertainties about food risks and the options for including views from different stakeholders, including members of the public, in risk assessment and risk management. Uncertainty is not only a major consideration of technical risk assessments but also needs to be understood within the two‐way interaction with various stakeholders, ranging from specialist risk managers to members of the public. We consider techniques for integration of technical risk assessment methodologies, including measures of the uncertainties, with social science inputs on participation processes, consumer behaviour and effective risk communication. We use case studies representing different types of risk – chemical contamination, and microbial contamination – to focus the discussion. The paper reviews the approach of ongoing interdisciplinary research which is exploring ways of communicating risks and involving members of the public and other stakeholders in defining the interfaces and processes needed.
RELU Special Issue: Editorial Reflections
Authors: Harvey David R.
Published: June 2006

This special issue is special in two major dimensions: the papers range intentionally over a much wider spectrum of social and natural science approaches and disciplines than is normal for the Journal of Agricultural Economics; and, the articles relate to ongoing research rather than completed work. These reflections, perhaps peculiar to a practicing applied economist and policy analyst, concentrate on the lessons to be learned and messages to be heard from the RELU programme, both by those engaged on the programme's research portfolio, and by other researchers.
Dehydroepiandrosterone Alleviates Copulatory Disorder Induced by Social Stress in Male Rats
Authors: Mizuno Tsuyoshi , Yotsuyanagi Satoshi , Nagasaka Yasuhiro , Namiki Mikio
Published: June 2006

Introduction

Social stress induces sexual dysfunction and reduces serum testosterone (T) level in rats. Stressful events exert an influence on a variety of behaviors and physiology through hormonal changes. The mechanism of stress-induced sexual dysfunction is unknown.

Aim

To investigate the role of dehydroepiandrosterone (DHEA) in copulatory behavior induced by social stress in rats.

Methods

Stress-induced male rats were subjected to social stress in which the males lived in a wire-mesh siege located in a colony of male and female rats and were exposed daily to a brief defeat by the colony of males for five consecutive days. After the stress period, copulatory behavior and serum concentrations of DHEA and T were measured.

Main Outcome Measures

The effects of DHEA, T, and NE-100, a selective sigma 1 receptor antagonist, on copulatory behavior following social stress were examined.

Results

The males exhibited a marked suppression of copulatory behavior (elongation of intromission and ejaculation latencies). Serum concentrations of DHEA and T were significantly lower than those in nonstressed control males. Another three groups of social stressed males were injected daily with DHEA, T, or DHEA + NE-100 during the stress period. Injections of DHEA attenuated the stress-induced suppression of copulatory behavior, whereas T had no effect. The combined treatment of NE-100 made DHEA ineffective at restoring copulatory behavior.

Conclusions

These results indicate that DHEA, but not its conversion to T, alleviates the suppressive effect of social stress on copulatory behavior via sigma 1 receptors. We suggest that the decreased endogenous DHEA is involved in copulatory disorders induced by social stress in rats.
Seed Dispersal by Geochelone carbonaria and Geochelone denticulata in Northwestern Brazil1
Authors: Strong Joel N. , Fragoso José M. V.
Published: June 2006

The role of red‐footed tortoises (Geochelone carbonaria) and yellow‐footed tortoises (G. denticulata) as seed dispersal agents was investigated in northwestern Brazil from 5 to 26 January 2002 by analyzing fecal samples for frequency and viability of seed species and estimating daily displacement of tortoises from recaptured and thread‐trailed individuals. Fourteen of 19 fecal samples contained a total of 646 seeds represented by 11 plant species. The most abundant species was Ficus sp. (N= 400) with 100 percent of seeds viable, followed by Aechmea sp. (N = 88) with 93 percent of seeds viable, and Genipa americana (N= 59) with 91 percent of seeds viable. Mean minimum retention time of seeds was 1.6 d and mean daily displacement of tortoises based on recaptured (N= 7) and thread‐trailed tortoises (N= 2) was 57 m. Thus, the diversity and proportion of viable seeds consumed by tortoises, combined with the seed retention times and daily movements, suggest they may be effective dispersal agents. These preliminary findings warrant further investigation into the ecological role of these tortoises in Neotropical ecosystems and their contribution to the maintenance of species diversity and forest structure.
GlnR-Mediated Regulation of Nitrogen Metabolism in
Lactococcus lactis
Authors: Larsen Rasmus , Kloosterman Tomas G. , Kok Jan , Kuipers Oscar P.
Published: June 2006

We show that the nitrogen regulatory protein GlnR of
Lactococcus lactis
represses transcription of the
amtB-glnK
,
glnRA
, and
glnPQ
operons. This likely occurs through a conserved DNA motif, 5′-TGTNA-7N-TNACAT-3′, and takes place in response to extracellular glutamine and ammonium. GlnR-independent repression of
amtB-glnK
is mediated by the pleiotropic nitrogen regulator CodY.
Characterization of the Primary Starch Utilization Operon in the Obligate Anaerobe
Bacteroides fragilis
: Regulation by Carbon Source and Oxygen
Authors: Spence Cheryl , Wells W. Greg , Smith C. Jeffrey
Published: June 2006

The opportunistic pathogen
Bacteroides fragilis
is a commensal organism in the large intestine, where it utilizes both dietary and host-derived polysaccharides as a source of carbon and energy. In this study, a four-gene operon required for starch utilization was identified. The operon also was found to be oxygen responsive and thus was designated
osu
for
o
xygen-induced
s
tarch
u
tilization. The first three genes in the operon were predicted to encode outer membrane proteins involved in starch binding, and a fourth gene,
osuD
, encoded an amylase involved in starch hydrolysis. Insertional mutation of the
osuA
gene (Ω
osuA
) resulted in the inability to utilize starch or glycogen and an insertional mutation into the
osuD
gene (Ω
osuD
) was severely impaired for growth on starch media. Transcriptional studies indicated that maltose, maltooligosaccharides, and starch were inducers of
osu
expression and that maltose was the strongest inducer. A transcriptional activator of
osuABCD
, OsuR, was identified and found to mediate maltose induction. The Ω
osuA
and Ω
osuD
mutants were able to grow on maltose but not starch, whereas a mutation in
osuR
abolished growth on both substrates, indicating that additional genes under the control of OsuR are needed for maltose utilization. The
osuABCD
operon also was induced by exposure to oxygen and was shown to be part of the oxidative stress response important for aerotolerance of
B. fragilis
. Transcriptional analyses showed that
osuA
was induced 20-fold by oxygen, but OsuR was not required for this activation. Analysis of
osu
mutants suggested that expression of the operon was important for survival during oxygen exposure but not to hydrogen peroxide stress.
Spx Is a Global Effector Impacting Stress Tolerance and Biofilm Formation inStaphylococcus aureus
Authors: Pamp Sünje Johanna , Frees Dorte , Engelmann Susanne , Hecker Michael , Ingmer Hanne
Published: June 2006

InBacillus subtilis, Spx was recently characterized as a novel type of global regulator whose activity is regulated by the redox status of the cells. In the present study, we demonstrate that inactivation of Spx in the important pathogenStaphylococcus aureusrenders the cells hypersensitive to a wide range of stress conditions including high and low temperature, high osmolarity, and hydrogen peroxide. Moreover, growth was restricted under nonstress conditions. Two-dimensional gel electrophoresis revealed that the proteome of thespxmutant differs substantially from the proteome of wild-type cells, supporting the finding that Spx is also a global regulator inS. aureus. More specifically, we demonstrated that Spx is required for transcription oftrxB, encoding thioredoxin reductase, under all growth conditions examined. AstrxBis essential inS. aureus, we speculate that the severely reducedtrxBtranscription could account for some of the growth defects of thespxmutant. Inactivation ofspxalso enhanced biofilm formation.S. aureusbiofilm formation is associated with the production of the polysaccharide intercellular adhesin encoded by theicaoperon. Interestingly, our data indicate that the augmented capacity of thespxmutant to form biofilms is due to Spx modulating the expression oficaR, encoding a repressor of the structuralicagenes (icaABCD). In summary, we conclude that Spx fulfills an important role for growth, general stress protection, and biofilm formation inS. aureus.
Phosphorylation of the Group A Streptococcal CovR Response Regulator Causes Dimerization and Promoter-Specific Recruitment by RNA Polymerase
Authors: Gusa Asiya A. , Gao Jinxin , Stringer Virginia , Churchward Gordon , Scott June R.
Published: June 2006

The group A streptococcus (GAS),
Streptococcus pyogenes
, is an important human pathogen that causes infections ranging in severity from self-limiting pharyngitis to severe invasive diseases that are associated with significant morbidity and mortality. The pathogenic effects of GAS are mediated by the expression of virulence factors, one of which is the hyaluronic acid capsule (encoded by genes in the
has
operon). The expression of these virulence factors is controlled by the CovR/S (CsrR/S) two-component regulatory system of GAS which regulates, directly or indirectly, the expression of about 15% of the genome. CovR is a member of the OmpR/PhoB family of transcriptional regulators. Here we show that phosphorylation by acetyl phosphate results in dimerization of CovR. Dimerization was not observed using a D53A mutant of CovR, indicating that D53 is the site of phosphorylation in CovR. Phosphorylation stimulated binding of CovR to a DNA fragment containing the promoter of the
has
operon (P
has
) approximately twofold. Binding of CovR D53A mutant protein to P
has
was indistinguishable from the binding of wild-type unphosphorylated CovR. In vitro transcription, using purified GAS RNA polymerase, showed that wild-type CovR repressed transcription, and repression was stimulated more than sixfold by phosphorylation. In the presence of RNA polymerase, binding at P
ha
s of phosphorylated, but not unphosphorylated, CovR was stimulated about fourfold, which accounts for the difference in the effect of phosphorylation on repression versus DNA binding. Thus, regulation of P
has
by CovR is direct, and the degree of repression of P
has
is controlled by the phosphorylation of CovR.
Transcriptional Regulation of the
Borrelia burgdorferi
Antigenically Variable VlsE Surface Protein
Authors: Bykowski Tomasz , Babb Kelly , von Lackum Kate , Riley Sean P. , Norris Steven J. , Stevenson Brian
Published: June 2006

The Lyme disease agent
Borrelia burgdorferi
can persistently infect humans and other animals despite host active immune responses. This is facilitated, in part, by the
vls
locus, a complex system consisting of the
vlsE
expression site and an adjacent set of 11 to 15 silent
vls
cassettes. Segments of nonexpressed cassettes recombine with the
vlsE
region during infection of mammalian hosts, resulting in combinatorial antigenic variation of the VlsE outer surface protein. We now demonstrate that synthesis of VlsE is regulated during the natural mammal-tick infectious cycle, being activated in mammals but repressed during tick colonization. Examination of cultured
B. burgdorferi
cells indicated that the spirochete controls
vlsE
transcription levels in response to environmental cues. Analysis of P
vlsE
::
gfp
fusions in
B. burgdorferi
indicated that VlsE production is controlled at the level of transcriptional initiation, and regions of 5′ DNA involved in the regulation were identified. Electrophoretic mobility shift assays detected qualitative and quantitative changes in patterns of protein-DNA complexes formed between the
vlsE
promoter and cytoplasmic proteins, suggesting the involvement of DNA-binding proteins in the regulation of
vlsE
, with at least one protein acting as a transcriptional activator.
Distinctive Repertoire of Contingency Genes Conferring Mutation- Based Phase Variation and Combinatorial Expression of Surface Lipoproteins in
Mycoplasma capricolum
subsp.
capricolum
of the
Mycoplasma mycoides
Phylogenetic Cluster
Authors: Wise Kim S. , Foecking Mark F. , Röske Kerstin , Lee Young Jin , Lee Young Moo , Madan Anup , Calcutt Michael J.
Published: June 2006

The generation of surface variation among many divergent species of
Mollicutes
(mycoplasmas) occurs through stochastic expression patterns of diverse lipoprotein genes. The size and wide distribution of such variable gene sets in minimal (∼0.6- to 1.4-Mb) mycoplasmal genomes suggest their key role in the adaptation and survival of these wall-less monoderms. Diversity through variable genes is less clearly established among phylogenetically similar mycoplasmas, such as the
Mycoplasma mycoides
cluster of ruminant pathogens, which vary widely in host range and pathobiology. Using (i) genome sequences from two members of this clade,
Mycoplasma capricolum
subsp.
capricolum
and
M. mycoides
subsp.
mycoides
small colony biotype (SC), (ii) antibodies to specific peptide determinants of predicted
M. capricolum
subsp.
capricolum
gene products, and (iii) analysis of the membrane-associated proteome of
M. capricolum
subsp.
capricolum
, a novel set of six genes (
vmcA
to
vmcF
) expressing distinct Vmc (variable
M. capricolum
subsp.
capricolum
) lipoproteins is demonstrated. These occur at two separate loci in the
M. capricolum
subsp.
capricolum
genome, which shares striking overall similarity and gene synteny with the
M. mycoides
subsp.
mycoides
SC genome. Collectively, Vmc expression is noncoordinate and combinatorial, subject to a single-unit insertion/deletion in a 5′ flanking dinucleotide repeat that governs expression of each
vmc
gene. All
vmc
genes share modular regions affecting expression and membrane translocation. In contrast,
vmcA
to
vmcD
genes at one locus express surface proteins with highly structured size-variable repeating domains, whereas
vmcE
to
vmcF
genes express products with short repeats devoid of predicted structure. These genes confer a distinctive, dynamic surface architecture that may represent adaptive differences within this important group of pathogens as well as exploitable diagnostic targets.
Regulation of Type IV Fimbrial Biogenesis in
Dichelobacter nodosus
Authors: Parker Dane , Kennan Ruth M. , Myers Garry S. , Paulsen Ian T. , Songer J. Glenn , Rood Julian I.
Published: June 2006

Type IV fimbriae are expressed by several bacterial pathogens and are essential for virulence in
Dichelobacter nodosus
, which causes ovine footrot. We have identified a two-component signal transduction system (PilR/S) and an alternative sigma factor (σ
54
) that were shown by insertional inactivation to be required for the regulation of fimbrial biogenesis in
D. nodosus
. Western blots showed that in both
pilR
and
rpoN
mutants, fimbrial subunit production was significantly reduced by a process that was shown to occur at a PilR- and σ
54
-dependent promoter. The mutants lacked surface fimbriae, which were shown to be required for the adherence of
D. nodosus
cells to tissue culture monolayers. The reduction in fimbrial subunit production in these mutants also resulted in a concomitant loss of the ability to secrete extracellular proteases. A maltose binding protein-PilR fusion protein was purified and was shown to bind specifically to a region located 234 to 594 bp upstream of the
fimA
transcriptional start point. To determine additional targets of PilR and σ
54
, genome-wide transcriptional profiling was performed using a whole-genome oligonucleotide microarray. The results indicated that PilR and σ
54
regulated genes other than
fimA
; these genes appear to encode surface-exposed proteins whose role in virulence is unknown. In conclusion, this study represents a significant advancement in our understanding of how the ability of
D. nodosus
to cause ovine footrot is regulated, as we have shown that the biogenesis of type IV fimbriae in
D. nodosus
is regulated by a σ
54
-dependent PilR/S system that also indirectly controls protease secretion.
Role of CheB and CheR in the Complex Chemotactic and Aerotactic Pathway of
Azospirillum brasilense
Authors: Stephens Bonnie B. , Loar Star N. , Alexandre Gladys
Published: June 2006

It has previously been reported that the alpha-proteobacterium
Azospirillum brasilense
undergoes methylation-independent chemotaxis; however, a recent study revealed
cheB
and
cheR
genes in this organism. We have constructed
cheB
,
cheR
, and
cheBR
mutants of
A. brasilense
and determined that the CheB and CheR proteins under study significantly influence chemotaxis and aerotaxis but are not essential for these behaviors to occur. First, we found that although cells lacking CheB, CheR, or both were no longer capable of responding to the addition of most chemoattractants in a temporal gradient assay, they did show a chemotactic response (albeit reduced) in a spatial gradient assay. Second, in comparison to the wild type,
cheB
and
cheR
mutants under steady-state conditions exhibited an altered swimming bias, whereas the
cheBR
mutant and the
che
operon mutant did not. Third,
cheB
and
cheR
mutants were null for aerotaxis, whereas the
cheBR
mutant showed reduced aerotaxis. In contrast to the swimming bias for the model organism
Escherichia coli
, the swimming bias in
A. brasilense
cells was dependent on the carbon source present and cells released methanol upon addition of some attractants and upon removal of other attractants. In comparison to the wild type, the
cheB
,
cheR
, and
cheBR
mutants showed various altered patterns of methanol release upon exposure to attractants. This study reveals a significant difference between the chemotaxis adaptation system of
A. brasilense
and that of the model organism
E. coli
and suggests that multiple chemotaxis systems are present and contribute to chemotaxis and aerotaxis in
A. brasilense
.
Functional Identification of Conjugation and Replication Regions of the Tetracycline Resistance Plasmid pCW3 fromClostridium perfringens
Authors: Bannam Trudi L. , Teng Wee Lin , Bulach Dieter , Lyras Dena , Rood Julian I.
Published: June 2006

Clostridium perfringenscauses fatal human infections, such as gas gangrene, as well as gastrointestinal diseases in both humans and animals. Detailed molecular analysis of the tetracycline resistance plasmid pCW3 fromC. perfringenshas shown that it represents the prototype of a unique family of conjugative antibiotic resistance and virulence plasmids. We have identified the pCW3 replication region by deletion and transposon mutagenesis and showed that the essentialrepgene encoded a basic protein with no similarity to any known plasmid replication proteins. An 11-gene conjugation locus containing 5 genes that encoded putative proteins with similarity to proteins from the conjugative transposon Tn916was identified, although the genes’ genetic arrangements were different. Functional genetic studies demonstrated that two of the genes in this transfer clostridial plasmid (tcp) locus,tcpFandtcpH, were essential for the conjugative transfer of pCW3, and comparative analysis confirmed that thetcplocus was not confined to pCW3. The conjugation region was present on all known conjugative plasmids fromC. perfringens, including an enterotoxin plasmid and other toxin plasmids. These results have significant implications for plasmid evolution, as they provide evidence that a nonreplicating Tn916-like element can evolve to become the conjugation locus of replicating plasmids that carry major virulence genes or antibiotic resistance determinants.
Staphylococcus aureus
Helicase but Not
Escherichia coli
Helicase Stimulates
S. aureus
Primase Activity and Maintains Initiation Specificity
Authors: Koepsell Scott A. , Larson Marilynn A. , Griep Mark A. , Hinrichs Steven H.
Published: June 2006

Bacterial primases are essential for DNA replication due to their role in polymerizing the formation of short RNA primers repeatedly on the lagging-strand template and at least once on the leading-strand template. The ability of recombinant
Staphylococcus aureus
DnaG primase to utilize different single-stranded DNA templates was tested using oligonucleotides of the sequence 5′-CAGA (CA)
5
XYZ (CA)
3
-3′, where XYZ represented the variable trinucleotide. These experiments demonstrated that
S. aureus
primase synthesized RNA primers predominately on templates containing 5′-d(CTA)-3′ or TTA and to a much lesser degree on GTA-containing templates, in contrast to results seen with the
Escherichia coli
DnaG primase recognition sequence 5′-d(CTG)-3′. Primer synthesis was initiated complementarily to the middle nucleotide of the recognition sequence, while the third nucleotide, an adenosine, was required to support primer synthesis but was not copied into the RNA primer. The replicative helicases from both
S. aureus
and
E. coli
were tested for their ability to stimulate either
S. aureus
or
E. coli
primase. Results showed that each bacterial helicase could only stimulate the cognate bacterial primase. In addition,
S. aureus
helicase stimulated the production of full-length primers, whereas
E. coli
helicase increased the synthesis of only short RNA polymers. These studies identified important differences between
E. coli
and
S. aureus
related to DNA replication and suggest that each bacterial primase and helicase may have adapted unique properties optimized for replication.
Interference between
Streptococcus pneumoniae
and
Staphylococcus aureus
: In Vitro Hydrogen Peroxide-Mediated Killing by
Streptococcus pneumoniae
Authors: Regev-Yochay Gili , Trzciński Krzysztof , Thompson Claudette M. , Malley Richard , Lipsitch Marc
Published: June 2006

The bactericidal activity of
Streptococcus pneumoniae
toward
Staphylococcus aureus
is mediated by hydrogen peroxide. Catalase eliminated this activity. Pneumococci grown anaerobically or genetically lacking pyruvate oxidase (SpxB) were not bactericidal, nor were nonpneumococcal streptococci. These results provide a possible mechanistic explanation for the interspecies interference observed in epidemiologic studies.
Cross-Regulation of Biphenyl- and Salicylate-Catabolic Genes by Two Regulatory Systems in
Pseudomonas pseudoalcaligenes
KF707
Authors: Fujihara Hidehiko , Yoshida Hideyuki , Matsunaga Tetsuya , Goto Masatoshi , Furukawa Kensuke
Published: June 2006

Pseudomonas pseudoalcaligenes
KF707 grows on biphenyl and salicylate as sole sources of carbon. The biphenyl-catabolic (
bph
) genes are organized as
bphR1A1A2
(
orf3
)
A3A4BCX0X1X2X3D
, encoding the enzymes for conversion of biphenyl to acetyl coenzyme A. In this study, the salicylate-catabolic (
sal
) gene cluster encoding the enzymes for conversion of salicylate to acetyl coenzyme A were identified 6.6-kb downstream of the
bph
gene cluster along with a second regulatory gene,
bphR2
. Both the
bph
and
sal
genes were cross-regulated positively and/or negatively by the two regulatory proteins, BphR1 and BphR2, in the presence or absence of the effectors. The BphR2 binding sequence exhibits homology with the NahR binding sequences in various naphthalene-degrading bacteria. Based on previous studies and the present study we propose a new regulatory model for biphenyl and salicylate catabolism in strain KF707.
Plasticity of the P
junc
Promoter of ISEc
11
, a New Insertion Sequence of the IS
1111
Family
Authors: Prosseda Gianni , Latella Maria Carmela , Casalino Mariassunta , Nicoletti Mauro , Michienzi Stefano , Colonna Bianca
Published: June 2006

We describe identification and functional characterization of ISEc
11
, a new insertion sequence that is widespread in enteroinvasive
E. coli
(EIEC), in which it is always present on the virulence plasmid (pINV) and very frequently also present on the chromosome. ISEc
11
is flanked by subterminal 13-bp inverted repeats (IRs) and is bounded by 3-bp terminal sequences, and it transposes with target specificity without generating duplication of the target site. ISEc
11
is characterized by an atypical transposase containing the DEDD motif of the Piv/MooV family of DNA recombinases, and it is closely related to the IS
1111
family. Transposition occurs by formation of minicircles through joining of the abutted ends and results in assembly of a junction promoter (P
juncC
) containing a −10 box in the interstitial sequence and a −35 box upstream of the right IR. A natural variant of ISEc
11
(ISEc
11
p), found on EIEC pINV plasmids, contains a perfect duplication of the outermost 39 bp of the right end. Upon circularization, ISEc
11
p forms a junction promoter (P
juncP
) which, despite carrying −10 and −35 boxes identical to those of P
juncC
, exhibits 30-fold-greater strength in vivo. The discovery of only one starting point in primer extension experiments rules out the possibility that there are alternative promoter sites within the 39-bp duplication. Analysis of in vitro-generated transcripts confirmed that at limiting RNA polymerase concentrations, the activity of P
juncP
is 20-fold higher than the activity of P
juncC
. These observations suggest that the 39-bp duplication might host
cis
-acting elements that facilitate the binding of RNA polymerase to the promoter.
Genomic Analysis of Carbon Source Metabolism of
Shewanella oneidensis
MR-1: Predictions versus Experiments
Authors: Serres Margrethe H. , Riley Monica
Published: June 2006

Genomic sequences have been used to find the genetic foundation for carbon source metabolism in
Shewanella oneidensis
MR-1. Annotated
S. oneidensis
MR-1 gene products were examined for their sequence similarity to enzymes participating in pathways for utilization of carbon and energy as described in the BioCyc database (
http://www.biocyc.org/
) or in the primary literature. A picture emerges that relegates five- and six-carbon sugars to minor roles as carbon sources, whereas multiple pathways for utilization of up to three-carbon carbohydrates seem to be present. Capacity to utilize amino acids for carbon and energy is also present. A few contradictions emerged in which enzymes appear to be present by annotations but are not active in the cell according to physiological experiments. Annotations are based on close sequence similarity and will not reveal inactivity due to deleterious mutations or due to lack of coordination of regulation and transport. Genes for a few enzymes known by experiment to be active are not found in the genome. This may be due to extensive divergence after duplication or convergence of function in separate lines in evolution rendering activities undetectable by sequence similarity. To minimize false predictions from protein sequences, we have been conservative in predicting pathways. We did not predict any pathway when, although a partial pathway was seen it was composed largely of enzymes already accounted for in any other complete pathway. This is an example of how a biochemically oriented sequence analysis can generate questions and direct further experimental investigation.