bluuebunny/crossref_metadata_2025 huggingface dataset:
Control of transforming growth factor β signal transduction by small GTPases
Authors: Kardassis Dimitris , Murphy Carol , Fotsis Theodore , Moustakas Aristidis , Stournaras Christos
Published: April 2009

The integrated roles of small GTPases in executing the transforming growth factor β (TGFβ) signaling pathway have attracted increasing attention in recent years. In this review, we summarize recent findings on TGFβ signaling during receptor endocytosis, Smad trafficking and actin cytoskeleton remodeling, and emphasize the role of small GTPases in these processes. First, we give an overview of the different endocytic routes taken by TGFβ receptors, their impact on active TGFβ signaling versus degradation and their regulation by the small GTPases Rab, RalA/Ral‐binding protein 1 and Rap2. Second, we focus on the mechanisms and regulation of Smad trafficking in the cytoplasm, through the nuclear pores and into the nucleus, and the contribution of Ran GTPase to these events. Third, we summarize the role of Rho small GTPases in early and late cytoskeleton remodeling in various cell models and diseases, and the positive and negative cross‐talk between Rho GTPases and the TGFβ/Smad pathway. The biological significance of this exciting research field, the perspectives and critical open questions are discussed.
Sexual Dysfunction Is Frequent in Premenopausal Women with Diabetes, Obesity, and Hypothyroidism, and Correlates with Markers of Increased Cardiovascular Risk. A Preliminary Report
Authors: Veronelli Annamaria , Mauri Chiara , Zecchini Barbara , Peca Maria Grazia , Turri Olivia , Valitutti Maria Teresa , Dall’Asta Chiara , Pontiroli Antonio E.
Published: April 2009

Introduction

Female sexual dysfunction (FSD) is characterized by reduced sexual appetite and altered psychologic and physiologic response to sexual intercourse; it is reported to be frequent in diabetes mellitus, but no data have been reported in thyroid disorders.

Aims

To compare the prevalence of FSD in diabetic, in obese, and in hypothyroid women vs. healthy women, and to correlate FSD with endocrine and metabolic profiles.

Methods

We evaluated, through a questionnaire (Female Sexual Function Index [FSFI]), the prevalence of FSD in 91 women affected by diabetes mellitus, obesity, or hypothyroidism, and in 36 healthy women, all aged 22–51 years and in premenopausal state.

Main Outcome Measures

FSFI score, endocrine and metabolic parameters (triglycerides, high-density lipoprotein [HDL] and low-density lipoprotein [LDL] cholesterol, free-triiodothyronine (FT3), free-thyroxine (FT4), thyroid stimulating hormone [TSH], 17-beta-estradiol, testosterone, glycated hemoglobin 1c (HbA1c), thyroid autoantibodies, E-selectin, P-selectin, intercellular adhesion molecule-1 [ICAM-1], plasminogen-activator inhibitor-1 [PAI-1]), and anthropometric parameters (body mass index, waist, blood pressure [BP]).

Results

A reduced FSFI score was more frequent in diabetic, obese, and hypothyroid women vs. healthy women (P < 0.01). In the different groups of women, FSFI score was inversely correlated (pairwise correlation) with at least one of the following: HbA1c, TSH, LDL-cholesterol, PAI-1, diastolic BP, presence of thyroid Ab, and directly correlated with HDL-cholesterol (always P < 0.05 or less). At stepwise regression analysis, HDL-cholesterol (protective) and HbA1c, LDL-cholesterol, PAI-1, and diastolic BP (negatively) predicted reduced FSFI score.

Conclusion

These data indicate an increased prevalence of sexual dysfunction in diabetic, in obese, and in hypothyroid women, associated with markers of cardiovascular risk.
Is a Shared Decision–Making Approach Effective in Improving Hypertension Management?
Authors: Deinzer Anja , Veelken Roland , Kohnen Ralf , Schmieder Roland E.
Published: April 2009

The authors assessed whether patient empowerment in the management of hypertension improved more with the practice of shared decision making (SDM) than by education programs. In a prospective controlled clinical study, 15 general practitioners in Nuremberg, Germany who were specially trained to conduct SDM consultations participated in a 12‐month study. Hypertensive patients (N=86) were included; N=40 were in the SDM group and N=46 were in the control group, if blood pressures were ≥135/85 mm Hg (self measurement) and patients had no signs of cardiovascular complications or severe hypertension. All participants in the SDM group and the control group were enrolled in an education program on hypertension in small groups. The SDM group participants also had 4 special consultations to share medical decisions. The main outcome measures were the effect of SDM on blood pressure control. After 1 year blood pressure had decreased in all participants: Δ−9.26±10.2 mm Hg/Δ−5.33±9.5 mm Hg in the SDM group (P<0.001) compared to Δ−6.0±11.8 mm Hg/Δ−3.0±8.3 mm Hg in the control group. There was no significant difference between the 2 groups. The study group practiced more SDM than controls, but blood pressure control was not significantly better. Patient empowerment by means of an education program in small groups and creating awareness of hypertensive disease helps to improve the outcome of hypertension treatment. SDM, however, did not improve management when compared to an education program, which is much easier to implement in general practice.
Species identification and sibship assignment of sympatric larvae in the yucca moths Tegeticula synthetica and Tegeticula antithetica (Lepidoptera: Prodoxidae)
Authors: DRUMMOND CHRISTOPHER S. , SMITH CHRISTOPHER I. , PELLMYR OLLE
Published: April 2009

Ecological interactions between yucca moths (Tegeticula, Prodoxidae) and their host plants (Yucca, Agavaceae) are exemplary of obligate plant–pollinator mutualism and co‐evolution. We describe a multiplex microsatellite DNA protocol for species identification and sibship assignment of sympatric larvae from Tegeticula synthetica and Tegeticula antithetica, pollinators of the Joshua tree (Yucca brevifolia). Bayesian clustering provides correct diagnosis of species in 100% of adult moths, with unambiguous identification of sympatric larvae. Sibship assignments show that larvae within a single fruit are more likely to be full‐sibs or half‐sibs than larvae from different fruit, consistent with the hypothesis that larval clutches are predominantly the progeny of an individual female.
A Mechanical Fourier Series Generator: An Exact Solution
Authors: Bucher Izhak
Published: April 2009

A vibrating system is constructed such that its natural frequencies are exact integer multiples of a base frequency. This system requires little energy to produce a periodic motion whose period is determined by the base frequency. The ability to amplify integer multiples of a base frequency makes this device an effective mechanical Fourier series generator. The proposed topology makes use of symmetry to assign poles and zeros at optimal frequencies. The system zeros play the role of suppressing the energy at certain frequencies while the poles amplify the input at their respective frequencies. An exact, non-iterative procedure is adopted to provide the stiffness and mass values of a discrete realization. It is shown that the spatial distributions of mass and stiffness are smooth; thus it is suggested that a continuous realization of a mechanical Fourier series generator is a viable possibility. A laboratory experiment and numerical examples are briefly described to validate the theory.
Front Condition for Gravity Currents in Channels of Nonrectangular Symmetric Cross-Section Shapes
Authors: Marino B. M. , Thomas L. P.
Published: April 2009

We study the variation of the Froude number at the front of gravity currents developed in uniform channels whose cross-section shape depends on a parameter usually used in many numerical and theoretical models. The thickness and front velocity of the dense currents running on the bottom are greater for all the cases studied, resulting in a Froude number greater than that corresponding to the rectangular cross-section shape. The light currents developing along the upper boundary show the opposite trend. It is found that the results are not related to the depth and width of the channel. The relationships obtained agree with the results of laboratory experiments in which open and closed channels of different cross-section shapes are used.
Drag Reduction in Turbulent Flow With Polymer Additives
Authors: Yang Shu-Qing
Published: April 2009

The mean velocity profile and friction factor in turbulent flows with polymer additives are investigated using Prandtl’s mixing-length theorem. This study reveals that the mixing-length theorem is valid to express the drag-reducing phenomenon and that the presence of polymer additives increases the damping factor B in van Driest’s model; subsequently reducing the mixing-length, this interprets that the polymer hampers the transfer of turbulent momentum flux, the velocity is increased, and flow drag is reduced. This study also discusses the onset Reynolds number for drag reduction to occur. The predicted velocity, friction factor, and onset Reynolds number are in good agreement with the measured data in the literature.
2D Navier–Stokes Simulations of Microscale Viscous Pump With Slip Flow
Authors: Bataineh Khaled M. , Al-Nimr Moh’d A.
Published: April 2009

In this paper we provide numerical solution of the Navier–Stokes equations coupled with energy equation for gaseous slip flow in two-dimensional microscale viscous pumps. A first-order slip boundary condition was applied to all internal solid walls. The objectives are to study the performance of the pumps and to study the effect of velocity slip on its performance. Mass flow rate and pump efficiency were calculated for various pump operation conditions when an external pressure load is applied at the pump exit plane. Geometric parameters were held fixed in this work. Microviscous pump performance was studied in detail for several values of the Reynolds number, pressure load, eccentricity, and slip factors. Our numerical results for no-slip were compared with previously published experimental and numerical data and were found to be in very good agreement. Slip values and eccentricity were found to be major parameters that affect the performance of pump. Pump head decreases with increasing slip factors. Maximum pump efficiency increases with increasing slip factor up to Kn approaching 0.1. However, the maximum value of pump efficiency is found to experience a steep degradation for Kn approaching 0.1. The values of moment coefficient always decrease as both slip factor and distance of the rotor from the lower wall increase. Also, as slip factors and distance of the rotor from the lower wall increase, less net flow rate is predicted. For a given fixed driving force at the rotor surface, there is an optimum value for the behavior of pump efficiency with distance of the rotor from the lower wall. Future research should be conducted to modify the current design to make this concept work for higher Knudsen numbers.
Experimental Study of a New Flow Conditioner on Disturbed Flow in Orifice Plate Metering
Authors: Ahmadi A.
Published: April 2009

The sensitivity to poor conditioned and swirling flow of flow measurements using an orifice plate are subjects of concern to flowmeter users and manufacturers. Measurements of mass flow rate under different conditions and different Reynolds numbers were used to establish a change in discharge coefficient relative to the standard one. The experimental results show that an optimally shaped flow conditioner could attenuate the effects of both swirl and asymmetrical flows. The optimization of the swirler flow conditioner is a main outcome of this work. So far the experimental results show that the cone swirler flow conditioner is the best one for swirling flow.
Tuning the Activation Threshold of a Kinase Network by Nested Feedback Loops
Authors: Justman Quincey A. , Serber Zach , Ferrell James E. , El-Samad Hana , Shokat Kevan M.
Published: April 2009

Interacting negative feedback loops control the sensitivity of amphibian oocytes to the hormone progesterone.
Where Is My Quantum Computer?
Authors: Hemmer P. , Wrachtrup J.
Published: April 2009

With applications in quantum cryptography, rudimentary quantum computers already exist.
The Thickness of Tectonic Plates
Authors: Romanowicz Barbara
Published: April 2009

Seismic studies continue to refine the elusive boundary that defines the depth at which the lithosphere ends.
Early Steps Toward Animal Rights
For the Love of Animals
The Rise of the Animal Protection Movement

by Kathryn Shevelow

Henry Holt, New York, 2008. 365 pp. $27.50, C$30.50. ISBN 9780805080902.
Authors: Gross Charles G.
Published: April 2009

Combining a cast of colorful reformers and vivid anecdotes about animals in British life of the 18th and early 19th centuries, Shevelow describes the development of the earliest animal welfare legislation.
Exploring Terra Incognita
Authors: Mabberley David J.
Published: April 2009

A tree new to science dominates the vegetation over an area of at least 8000 km
2
in an African war zone.
To Divide or Not to Divide
Authors: Skotheim Jan M.
Published: April 2009

The analysis of signaling circuits governed by threshold-sensitive switches may reveal why a particular network architecture is selected to control a biological process.
A New Take on Doping in Iron-Based Superconductors
Authors: Cho Adrian
Published: April 2009

At the German Physical Society meeting, researchers reported on new data suggesting that a key step in making both iron-based and copper-based superconductors--"doping" them with impurities--plays a very different role in each of the two families.
A New Look at the Mayas' End
Authors: Pringle Heather
Published: April 2009

Climate reaserchers have fingered drought in the collapse of the great Maya civilization, but many archaeologists say it doesn't fit their data. Ultralocal paleoclimate indicators may spark a resolution
Jim Kim on Why He Took the Top Job at Dartmouth
Authors: Cohen Jon
Published: April 2009

An Ivy League school has broken new ground by hiring an Asian global health specialist to build its future
Effect of pH and Temperature on Denitrification Gene Expression and Activity in
Pseudomonas mandelii
Authors: Saleh-Lakha Saleema , Shannon Kelly E. , Henderson Sherri L. , Goyer Claudia , Trevors Jack T. , Zebarth Bernie J. , Burton David L.
Published: April 2009

Pseudomonas mandelii
liquid cultures were studied to determine the effect of pH and temperature on denitrification gene expression, which was quantified by quantitative reverse transcription-PCR. Denitrification was measured by the accumulation of nitrous oxide (N
2
O) in the headspace in the presence of acetylene. Levels of gene expression of
nirS
and
cnorB
at pH 5 were 539-fold and 6,190-fold lower, respectively, than the levels of gene expression for cells grown at pH 6, 7, and 8 between 4 h and 8 h. Cumulative denitrification levels were 28 μmol, 63 μmol, and 22 μmol at pH 6, 7, and 8, respectively, at 8 h, whereas negligible denitrification was measured at pH 5.
P. mandelii
cells grown at 20°C and 30°C exhibited 9-fold and 94-fold increases in levels of
cnorB
expression between 0 h and 2 h, respectively, and an average 17-fold increase in levels of
nirS
gene expression. In contrast, induction of
cnorB
and
nirS
gene expression for
P. mandelii
cells grown at 10°C did not occur in the first 4 h. Levels of cumulative denitrification at 10 h were 6.6 μmol for
P. mandelii
cells grown at 10°C and 20°C and 30 μmol for cells grown at 30°C. Overall, levels of
cnorB
and
nirS
expression were relatively insensitive to pH values over the range of pH 6 to 8 but were substantially reduced at pH 5, whereas gene expression was sensitive to temperature, with induction and time to achieve maximum gene expression delayed as the temperature decreased from 30°C. Low pH and temperature negatively affected denitrification activity.
The Haloprotease CPI Produced by the Moderately Halophilic Bacterium
Pseudoalteromonas ruthenica
Is Secreted by the Type II Secretion Pathway
Authors: Sánchez-Porro Cristina , Mellado Encarnación , Pugsley Anthony P. , Francetic Olivera , Ventosa Antonio
Published: April 2009

The gene (
cpo
) encoding the extracellular protease CPI produced by the moderately halophilic bacterium
Pseudoalteromonas ruthenica
CP76 was cloned, and its nucleotide sequence was analyzed. The
cpo
gene encodes a 733-residue protein showing sequence similarity to metalloproteases of the M4 family. The type II secretion apparatus was shown to be responsible for secretion of the haloprotease CPI.
Regulation of Expression of Genes Involved in Quinate and Shikimate Utilization in
Corynebacterium glutamicum
Authors: Teramoto Haruhiko , Inui Masayuki , Yukawa Hideaki
Published: April 2009

The utilization of the hydroaromatic compounds quinate and shikimate by
Corynebacterium glutamicum
was investigated.
C. glutamicum
grew well with either quinate or shikimate as the sole carbon source. The disruption of
qsuD
, encoding quinate/shikimate dehydrogenase, completely suppressed growth with either substrate but did not affect growth with glucose, indicating that the enzyme encoded by
qsuD
catalyzes the first step of the catabolism of quinate/shikimate but is not involved in the shikimate pathway required for the biosynthesis of various aromatic compounds. On the chromosome of
C. glutamicum
, the
qsuD
gene is located in a gene cluster also containing
qsuA, qsuB
, and
qsuC
genes, which are probably involved in the quinate/shikimate utilization pathway to form protocatechuate. Reverse transcriptase PCR analyses revealed that the expression of the
qsuABCD
genes was markedly induced during growth with either quinate or shikimate relative to expression during growth with glucose. The induction level by shikimate was significantly decreased by the disruption of
qsuR
, which is located immediately upstream of
qsuA
in the opposite direction and encodes a LysR-type transcriptional regulator, suggesting that QsuR acts as an activator of the
qsuABCD
genes. The high level of induction of
qsuABCD
genes by shikimate was still observed in the presence of glucose, and simultaneous consumption of glucose and shikimate during growth was observed.
Characterization of Bacterial Magnetotactic Behaviors by Using a Magnetospectrophotometry Assay
Authors: Lefèvre Christopher T. , Song Tao , Yonnet Jean-Paul , Wu Long-Fei
Published: April 2009

Magnetotactic bacteria have the unique capacity of synthesizing intracellular single-domain magnetic particles called magnetosomes. The magnetosomes are usually organized in a chain that allows the bacteria to align and swim along geomagnetic field lines, a behavior called magnetotaxis. Two mechanisms of magnetotaxis have been described. Axial magnetotactic cells swim in both directions along magnetic field lines. In contrast, polar magnetotactic cells swim either parallel to the geomagnetic field lines toward the North Pole (north seeking) or antiparallel toward the South Pole (south seeking). In this study, we used a magnetospectrophotometry (MSP) assay to characterize both the axial magnetotaxis of “
Magnetospirillum magneticum
” strain AMB-1 and the polar magnetotaxis of magneto-ovoid strain MO-1. Two pairs of Helmholtz coils were mounted onto the cuvette holder of a common laboratory spectrophotometer to generate two mutually perpendicular homogeneous magnetic fields parallel or perpendicular to the light beam. The application of magnetic fields allowed measurements of the change in light scattering resulting from cell alignment in a magnetic field or in absorbance due to bacteria swimming across the light beam. Our results showed that MSP is a powerful tool for the determination of bacterial magnetism and the analysis of alignment and swimming of magnetotactic bacteria in magnetic fields. Moreover, this assay allowed us to characterize south-seeking derivatives and non-magnetosome-bearing strains obtained from north-seeking MO-1 cultures. Our results suggest that oxygen is a determinant factor that controls magnetotactic behavior.
Possible Environmental Origin of Resistance of
Aspergillus fumigatus
to Medical Triazoles
Authors: Snelders Eveline , Huis in 't Veld Robert A. G. , Rijs Anthonius J. M. M. , Kema Gert H. J. , Melchers Willem J. G. , Verweij Paul E.
Published: April 2009

We reported the emergence of resistance to medical triazoles of
Aspergillus fumigatus
isolates from patients with invasive aspergillosis. A dominant resistance mechanism was found, and we hypothesized that azole resistance might develop through azole exposure in the environment rather than in azole-treated patients. We investigated if
A. fumigatus
isolates resistant to medical triazoles are present in our environment by sampling the hospital indoor environment and soil from the outdoor environment. Antifungal susceptibility, resistance mechanisms, and genetic relatedness were compared with those of azole-resistant clinical isolates collected in a previous study. Itraconazole-resistant
A. fumigatus
(five isolates) was cultured from the indoor hospital environment as well as from soil obtained from flower beds in proximity to the hospital (six isolates) but never from natural soil. Additional samples of commercial compost, leaves, and seeds obtained from a garden center and a plant nursery were also positive (four isolates). Cross-resistance was observed for voriconazole, posaconazole, and the azole fungicides metconazole and tebuconazole. Molecular analysis showed the presence of the dominant resistance mechanism, which was identical to that found in clinical isolates, in 13 of 15 environmental isolates, and it showed that environmental and clinical isolates were genetically clustered apart from nonresistant isolates. Patients with azole-resistant aspergillosis might have been colonized with azole-resistant isolates from the environment.
Uncultivated Magnetotactic Cocci from Yuandadu Park in Beijing, China
Authors: Lin Wei , Pan Yongxin
Published: April 2009

In the present study, we investigated a group of uncultivated magnetotactic cocci, which was magnetically isolated from a freshwater pond in Beijing, China. Light and transmission electron microscopy showed that these cocci ranged from 1.5 to 2.5 μm and contained two to four chains of magnetite magnetosomes, which sometimes were partially disorganized. Overall, the size of the disorganized magnetosomes was significantly smaller than that arranged in chains. All characterized magnetosome crystals were elongated (shape factor = 0.64) and fall into the single-domain size range (30 to 115 nm). Comparative 16S rRNA gene sequence analysis and fluorescence in situ hybridization showed that the enriched bacteria were a virtually homogeneous population and represented a novel lineage in the
Alphaproteobacteria
. The closest cultivated relative was magnetotactic coccoid strain MC-1 (88% sequence identity). First-order reversal curve diagrams revealed that these cocci had relatively strong magnetic interactions compared to the single-chain magnetotactic bacteria. Low-temperature magnetic measurements showed that the Verwey transition of them was ∼108 K, confirming magnetite magnetosomes, and the delta ratio δ
FC
/δ
ZFC
was >2. Based on the structure, phylogenetic position and magnetic properties, the enriched magnetotactic cocci of
Alphaproteobacteria
are provisionally named as “
Candidatus
Magnetococcus yuandaducum.”
Rhizobiumsp. Strain NGR234 Possesses a Remarkable Number of Secretion Systems
Authors: Schmeisser Christel , Liesegang Heiko , Krysciak Dagmar , Bakkou Nadia , Le Quéré Antoine , Wollherr Antje , Heinemeyer Isabelle , Morgenstern Burkhard , Pommerening-Röser Andreas , Flores Margarita , Palacios Rafael , Brenner Sydney , Gottschalk Gerhard , Schmitz Ruth A. , Broughton William J. , Perret Xavier , Strittmatter Axel W. , Streit Wolfgang R.
Published: April 2009

Rhizobiumsp. strain NGR234 is a unique alphaproteobacterium (orderRhizobiales) that forms nitrogen-fixing nodules with more legumes than any other microsymbiont. We report here that the 3.93-Mbp chromosome (cNGR234) encodes most functions required for cellular growth. Few essential functions are encoded on the 2.43-Mbp megaplasmid (pNGR234b), and none are present on the second 0.54-Mbp symbiotic plasmid (pNGR234a). Among many striking features, the 6.9-Mbp genome encodes more different secretion systems than any other known rhizobia and probably most known bacteria. Altogether, 132 genes and proteins are linked to secretory processes. Secretion systems identified include general and export pathways, a twin arginine translocase secretion system, six type I transporter genes, one functional and one putative type III system, three type IV attachment systems, and two putative type IV conjugation pili. Type V and VI transporters were not identified, however. NGR234 also carries genes and regulatory networks linked to the metabolism of a wide range of aromatic and nonaromatic compounds. In this way, NGR234 can quickly adapt to changing environmental stimuli in soils, rhizospheres, and plants. Finally, NGR234 carries at least six loci linked to the quenching of quorum-sensing signals, as well as one gene (ngrI) that possibly encodes a novel type of autoinducer I molecule.
Differential
Listeria monocytogenes
Strain Survival and Growth in Katiki, a Traditional Greek Soft Cheese, at Different Storage Temperatures
Authors: Kagkli Dafni-Maria , Iliopoulos Vassilios , Stergiou Virginia , Lazaridou Anna , Nychas George-John
Published: April 2009

Katiki Domokou is a traditional Greek cheese, which has received the Protected Designation of Origin recognition since 1994. Its microfloras have not been studied although its structure and composition may enable (or even favor) the survival and growth of several pathogens, including
Listeria monocytogenes
. The persistence of
L. monocytogenes
during storage at different temperatures has been the subject of many studies since temperature abuse of food products is often encountered. In the present study, five strains of
L. monocytogenes
were aseptically inoculated individually and as a cocktail in Katiki Domokou cheese, which was then stored at 5, 10, 15, and 20°C. Pulsed-field gel electrophoresis was used to monitor strain evolution or persistence during storage at different temperatures in the case of the cocktail inoculum. The results suggested that strain survival of
L. monocytogenes
was temperature dependent since different strains predominated at different temperatures. Such information is of great importance in risk assessment studies, which typically consider only the presence or absence of the pathogen.
Generation of Electricity and Analysis of Microbial Communities in Wheat Straw Biomass-Powered Microbial Fuel Cells
Authors: Zhang Yifeng , Min Booki , Huang Liping , Angelidaki Irini
Published: April 2009

Electricity generation from wheat straw hydrolysate and the microbial ecology of electricity-producing microbial communities developed in two-chamber microbial fuel cells (MFCs) were investigated. The power density reached 123 mW/m
2
with an initial hydrolysate concentration of 1,000 mg chemical oxygen demand (COD)/liter, while coulombic efficiencies ranged from 37.1 to 15.5%, corresponding to the initial hydrolysate concentrations of 250 to 2,000 mg COD/liter. The suspended bacteria found were different from the bacteria immobilized in the biofilm, and they played different roles in electricity generation from the hydrolysate. The bacteria in the biofilm were consortia with sequences similar to those of
Bacteroidetes
(40% of sequences),
Alphaproteobacteria
(20%),
Bacillus
(20%),
Deltaproteobacteria
(10%), and
Gammaproteobacteria
(10%), while the suspended consortia were predominately
Bacillus
(22.2%). The results of this study can contribute to improving understanding of and optimizing electricity generation in microbial fuel cells.
Spatial Patterns in Hyphal Growth and Substrate Exploitation within Norway Spruce Stems Colonized by the Pathogenic White-Rot Fungus
Heterobasidion parviporum
Authors: Hietala Ari M. , Nagy Nina E. , Steffenrem Arne , Kvaalen Harald , Fossdal Carl G. , Solheim Halvor
Published: April 2009

In Norway spruce, a fungistatic reaction zone with a high pH and enrichment of phenolics is formed in the sapwood facing heartwood colonized by the white-rot fungus
Heterobasidion parviporum
. Fungal penetration of the reaction zone eventually results in expansion of this xylem defense. To obtain information about mechanisms operating upon heartwood and reaction zone colonization by the pathogen, hyphal growth and wood degradation were investigated using real-time PCR, microscopy, and comparative wood density analysis of naturally colonized trees with extensive stem decay. The hyphae associated with delignified wood at stump level were devoid of any extracellular matrix, whereas incipient decay at the top of decay columns was characterized by a carbohydrate-rich hyphal sheath attaching hyphae to tracheid walls. The amount of pathogen DNA peaked in aniline wood, a narrow darkened tissue at the colony border apparently representing a compromised region of the reaction zone. Vigorous production of pathogen conidiophores occurred in this region. Colonization of aniline wood was characterized by hyphal growth within polyphenolic lumen deposits in tracheids and rays, and the hyphae were fully encased in a carbohydrate-rich extracellular matrix. Together, these data indicate that the interaction of the fungus with the reaction zone involves a local concentration of fungal biomass that forms an efficient translocation channel for nutrients. Finally, the enhanced production of the hyphal sheath may be instrumental in lateral expansion of the decay column beyond the reaction zone boundary.
CpxRA Influences
Xenorhabdus nematophila
Colonization Initiation and Outgrowth in
Steinernema carpocapsae
Nematodes through Regulation of the
nil
Locus
Authors: Herbert Tran Erin E. , Andersen Aaron W. , Goodrich-Blair Heidi
Published: April 2009

The gammaproteobacterium
Xenorhabdus nematophila
mutualistically colonizes an intestinal region of a soil-dwelling nematode and is a blood pathogen of insects. The
X. nematophila
CpxRA two-component regulatory system is necessary for both of these host interactions (E. Herbert et al., Appl. Environ. Microbiol. 73:7826-7836, 2007). Mutualistic association of
X. nematophila
with its nematode host consists of two stages: initiation, where a small number of bacterial cells establish themselves in the colonization site, and outgrowth, where these cells grow to fill the space. In this study, we show that the Cpx system is necessary for both of these stages.
X. nematophila
Δ
cpxR1
colonized fewer nematodes than its wild-type parent and did not achieve as high a density as did the wild type within a portion of the colonized nematodes. To test whether the Δ
cpxR1
host interaction phenotypes are due to its overexpression of
mrxA
, encoding the type I pilin subunit protein, we assessed the colonization phenotype of a Δ
cpxR1
Δ
mrxA1
double mutant. This mutant displayed the same colonization defect as Δ
cpxR1
, indicating that CpxR negative regulation of
mrxA
does not play a detectable role in
X. nematophila
-host interactions. CpxR positively regulates expression of
nilA
,
nilB
, and
nilC
genes necessary for nematode colonization. Here we show that the nematode colonization defect of the Δ
cpxR1
mutant is rescued by elevating
nil
gene expression through mutation of
nilR
, a negative regulator of
nilA
,
nilB
, and
nilC
. These data suggest that the nematode colonization defect previously observed in Δ
cpxR1
is caused, at least in part, by altered regulation of
nilA
,
nilB
, and
nilC
.
Detection of Live
Salmonella
sp. Cells in Produce by a TaqMan-Based Quantitative Reverse Transcriptase Real-Time PCR Targeting
invA
mRNA
Authors: González-Escalona Narjol , Hammack Thomas S. , Russell Mindi , Jacobson Andrew P. , De Jesús Antonio J. , Brown Eric W. , Lampel Keith A.
Published: April 2009

Salmonella enterica
contamination in foods is a significant concern for public health. When DNA detection methods are used for analysis of foods, one of the major concerns is false-positive results from the detection of dead cells. To circumvent this crucial issue, a TaqMan quantitative real-time RT-PCR (qRT-PCR) assay with an RNA internal control was developed.
invA
RNA standards were used to determine the detection limit of this assay as well as to determine
invA
mRNA levels in mid-exponential-, late-exponential-, and stationary-phase cells. This assay has a detection limit of 40 copies of
invA
mRNA per reaction. The levels of
invA
mRNA in mid-exponential-, late-exponential-, and stationary-phase
S. enterica
cells was approximately 1 copy per 3 CFU, 1 copy per CFU, and 4 copies per 10
3
CFU, respectively. Spinach, tomatoes, jalapeno peppers, and serrano peppers were artificially contaminated with four different
Salmonella
serovars at levels of 10
5
and less than 10 CFU. These foods were analyzed with qRT-PCR and with the FDA's
Bacteriological Analytical Manual Salmonella
culture method (W. A. Andrews and T. S. Hammack,
in
G. J. Jackson et al., ed., Bacteriological analytical manual online,
http://www.cfsan.fda.gov/∼ebam/bam-5.html
, 2007). Comparable results were obtained by both methods. Only live
Salmonella
cells could be detected by this qRT-PCR assay, thus avoiding the dangers of false-positive results from nonviable cells. False negatives (inhibition of the PCR) were also ruled out through the use of an RNA internal control. This assay allows for the fast and accurate detection of viable
Salmonella
spp. in spinach, tomatoes, and in both jalapeno and serrano peppers.
Effect of Octenidine Hydrochloride on Planktonic Cells and Biofilms of
Listeria monocytogenes
Authors: Amalaradjou Mary Anne Roshni , Norris Carol E. , Venkitanarayanan Kumar
Published: April 2009

Listeria monocytogenes
is a food-borne pathogen capable of forming biofilms and persisting in food processing environments for extended periods of time, thereby potentially contaminating foods. The efficacy of octenidine hydrochloride (OH) for inactivating planktonic cells and preformed biofilms of
L. monocytogenes
was investigated at 37, 21, 8, and 4°C in the presence and absence of organic matter (rehydrated nonfat dry milk). OH rapidly killed planktonic cells and biofilms of
L. monocytogenes
at all four temperatures. Moreover, OH was equally effective in killing
L. monocytogenes
biofilms on polystyrene and stainless steel matrices in the presence and absence of organic matter. The results underscore OH's ability to prevent establishment of
L. monocytogenes
biofilms by rapidly killing planktonic cells and to eliminate preformed biofilms, thus suggesting that it could be used as a disinfectant to prevent
L. monocytogenes
from persisting in food processing environments.
Coaggregation by the Freshwater Bacterium
Sphingomonas natatoria
Alters Dual-Species Biofilm Formation
Authors: Min K. R. , Rickard A. H.
Published: April 2009

Coaggregation is hypothesized to enhance freshwater biofilm development. To investigate this hypothesis, the ability of the coaggregating bacterium
Sphingomonas natatoria
to form single- and dual-species biofilms was studied and compared to that of a naturally occurring spontaneous coaggregation-deficient variant. Attachment assays using metabolically inactive cells were performed using epifluorescence and confocal laser scanning microscopy. Under static and flowing conditions, coaggregating
S. natatoria
2.1gfp cells adhered to glass surfaces to form diaphanous single-species biofilms. When glass surfaces were precoated with coaggregation partner
Micrococcus luteus
2.13 cells,
S. natatoria
2.1gfp cells formed densely packed dual-species biofilms. The addition of 80 mM galactosamine, which reverses coaggregation, mildly reduced adhesion to glass but inhibited the interaction and attachment to glass-surface-attached
M. luteus
2.13 cells. As opposed to wild-type coaggregating cells, coaggregation-deficient
S. natatoria
2.1COGgfp variant cells were retarded in colonizing glass and did not interact with glass-surface-attached
M. luteus
2.13 cells. To determine if coaggregation enhances biofilm growth and expansion, viable coaggregating
S. natatoria
2.1gfp cells or the coaggregation-deficient variant
S. natatoria
2.1COGgfp cells were coinoculated in flow cells with viable
M. luteus
2.13 cells and allowed to grow together for 96 h. Coaggregating
S. natatoria
2.1gfp cells outcompeted
M. luteus
2.13 cells, and 96-h biofilms were composed predominantly of
S. natatoria
2.1gfp cells. Conversely, when coaggregation-deficient
S. natatoria
2.1COGgfp cells were coinoculated with
M. luteus
2.13 cells, the 96-h biofilm contained few coaggregation-deficient
S. natatoria
2.1 cells. Thus, coaggregation promotes biofilm integration by facilitating attachment to partner species and likely contributes to the expansion of coaggregating
S. natatoria
2.1 populations in dual-species biofilms through competitive interactions.
Mutations in Domain I Interhelical Loops Affect the Rate of Pore Formation by the
Bacillus thuringiensis
Cry1Aa Toxin in Insect Midgut Brush Border Membrane Vesicles
Authors: Lebel Geneviève , Vachon Vincent , Préfontaine Gabrielle , Girard Frédéric , Masson Luke , Juteau Marc , Bah Aliou , Larouche Geneviève , Vincent Charles , Laprade Raynald , Schwartz Jean-Louis
Published: April 2009

Pore formation in the apical membrane of the midgut epithelial cells of susceptible insects constitutes a key step in the mode of action of
Bacillus thuringiensis
insecticidal toxins. In order to study the mechanism of toxin insertion into the membrane, at least one residue in each of the pore-forming-domain (domain I) interhelical loops of Cry1Aa was replaced individually by cysteine, an amino acid which is normally absent from the activated Cry1Aa toxin, using site-directed mutagenesis. The toxicity of most mutants to
Manduca sexta
neonate larvae was comparable to that of Cry1Aa. The ability of each of the activated mutant toxins to permeabilize
M. sexta
midgut brush border membrane vesicles was examined with an osmotic swelling assay. Following a 1-h preincubation, all mutants except the V150C mutant were able to form pores at pH 7.5, although the W182C mutant had a weaker activity than the other toxins. Increasing the pH to 10.5, a procedure which introduces a negative charge on the thiol group of the cysteine residues, caused a significant reduction in the pore-forming abilities of most mutants without affecting those of Cry1Aa or the I88C, T122C, Y153C, or S252C mutant. The rate of pore formation was significantly lower for the F50C, Q151C, Y153C, W182C, and S252C mutants than for Cry1Aa at pH 7.5. At the higher pH, all mutants formed pores significantly more slowly than Cry1Aa, except the I88C mutant, which formed pores significantly faster, and the T122C mutant. These results indicate that domain I interhelical loop residues play an important role in the conformational changes leading to toxin insertion and pore formation.
Composition of Bacterial Communities Associated with Natural and Laboratory Populations of
Asobara tabida
Infected with
Wolbachia
Authors: Zouache Karima , Voronin Denis , Tran-Van Van , Mavingui Patrick
Published: April 2009

Asobara tabida
wasps are fly endoparasitoids that naturally harbor three
Wolbachia
strains, which induce cytoplasmic incompatibility and control oogenesis. To investigate whether other bacteria play a role in wasp biology, we surveyed the bacterial communities of wild
A. tabida
populations originating from different regions of France and of laboratory colonies using PCR-denaturing gradient gel electrophoresis and culture methods.
Proteobacteria
and
Firmicutes
were found to be the main phyla represented in these populations. Among these were several cultured and uncultured representatives of the genera
Acetobacter
,
Acidomonas
,
Bacillus
,
Brevibacillus
,
Duganella
,
Herbaspirillum
,
Pseudomonas
,
Staphylococcus
, and
Streptococcus
. In addition to
Wolbachia
, wild individuals harbored
Rickettsia
, which tended to be lost when insects were reared in the laboratory. The antibiotic treatment used to generate wasp sublines singly infected with
Wolbachia
also affected the overall bacterial composition, with most fingerprint sequences being characteristic of the family
Enterobacteriaceae
. We also screened for potentially heritable endosymbionts by PCR and fluorescence in situ hybridization in stable laboratory lines, with only
Wolbachia
being consistently found in wasp ovaries.
Identification and Characterization of a Novel Gene Involved in the
trans
-Specific Nematicidal Activity of
Photorhabdus luminescens
LN2
Authors: Qiu Xuehong , Han Richou , Yan Xun , Liu Mingxing , Cao Li , Yoshiga Toyoshi , Kondo Eizo
Published: April 2009

Photorhabdus luminescens
subsp.
akhurstii
LN2 from
Heterorhabditis indica
LN2 showed nematicidal activity against axenic
Heterorhabditis bacteriophora
H06 infective juveniles (IJs). Transposon mutagenesis identified an LN2 mutant that supports the growth of H06 nematodes. Tn
5
disrupted the
namA
gene, encoding a novel 364-residue protein and involving the nematicidal activity. The green fluorescent protein-labeled
namA
mutant was unable to colonize the intestines of H06 IJs.
Sonicated Diagnostic Immunoblot for Bartonellosis
Authors: Mallqui Vania , Speelmon Emily C. , Verástegui Manuela , Maguiña-Vargas Ciro , Pinell-Salles Paula , Lavarello Rosa , Delgado Jose , Kosek Margaret , Romero Sofia , Arana Yanina , Gilman Robert H.
Published: April 2009

Two simple
Bartonella bacilliformis
immunoblot preparation methods were developed. Antigen was prepared by two different methods: sonication of whole organisms or glycine extraction. Both methods were then tested for sensitivity and specificity. Well-defined control sera were utilized in the development of these diagnostic immunoblots, and possible cross-reactions were thoroughly examined. Sera investigated for cross-reaction with these diagnostic antigens were drawn from patients with brucellosis, chlamydiosis, Q fever, and cat scratch disease, all of whom were from regions where bartonellosis is not endemic. While both immunoblots yielded reasonable sensitivity and high specificity, we recommend the use of the sonicated immunoblot, which has a higher sensitivity when used to detect acute disease and produces fewer cross-reactions. The sonicated immunoblot reported here is 94% sensitive to chronic bartonellosis and 70% sensitive to acute bartonellosis. In a healthy group, it is 100% specific. This immunoblot preparation requires a simple sonication protocol for the harvesting of
B. bacilliformis
antigens and is well suited for use in regions of endemicity.
Serum Cytokine Responses during Acute Human Granulocytic Ehrlichiosis
Authors: Dumler J. S. , Trigiani E. R. , Bakken J. S. , Aguero-Rosenfeld M. E. , Wormser G. P.
Published: April 2009

Human granulocytic ehrlichiosis (HGE) is caused by obligate intracellular bacteria in theEhrlichia phagocytophilagroup. The disease ranges from subclinical to fatal. We speculated that cell-mediated immunity would be important for recovery from and potentially in the clinical manifestations of HGE; thus, serum tumor necrosis factor alpha (TNF-α), interleukin 1β (IL-1β), gamma interferon (IFN-γ), IL-10, and IL-4 concentrations were studied. IFN-γ (1,035 ± 235 pg/ml [mean ± standard error of the mean]) and IL-10 (118 ± 46 pg/ml) concentrations were elevated in acute-phase sera versus convalescent sera and normal subjects (P ≤ 0.013 andP ≤ 0.018, respectively). TNF-α, IL-1β, and IL-4 levels were not elevated. Cytokine levels in severely and mildly affected patients were not different. HGE leads to induction of IFN-γ-dominated cell-mediated immunity associated with clinical manifestations, recovery from infection, or both.
Altered Expression of TAP-1 and Major Histocompatibility Complex Class I in Laryngeal Papillomatosis: Correlation of TAP-1 with Disease
Authors: Vambutas Andrea , Bonagura Vincent R. , Steinberg Bettie M.
Published: April 2009

Recurrent respiratory papillomatosis (RRP) is an insidious disease caused by human papillomavirus (HPV) infection. It is characterized by a variable clinical course that can include frequent disease recurrence, significant morbidity, and occasional mortality. The mechanisms responsible for the variability in the clinical course and the persistence of latent HPV infection remain unknown. Effective T-cell-mediated clearance of HPV-infected cells may be defective in patients with RRP, leading to recurrent disease and failure to suppress latent HPV reactivation. This study describes the down-regulation of the transporter associated with antigen presentation (TAP-1) and the major histocompatibility complex (MHC) class I protein expression in laryngeal papilloma tissue biopsies and cell culture of primary explants. There was a statistically significant correlation between reduction of TAP-1 expression in biopsy tissues and rapid recurrence of disease. Patients with RRP had less frequent recurrence if their papillomas expressed TAP-1 at levels close to that of normal tissue, compared with those with very low expression of TAP-1, who had frequent recurrence (32 versus 5 weeks to the next surgical intervention). These findings suggest that HPV may evade immune recognition by down-regulating class I MHC cell surface expression via decreased TAP-1 levels. Expression of TAP-1 could be used for prognostic evaluation of disease severity. Gamma interferon was able to restore class I MHC expression at the surfaces of laryngeal papilloma cells in culture. This up-regulation of class I MHC antigen at the cell surface potentially allows the infected cell to become a target for the immune system again. This finding provides some promise for nonsurgical treatment of laryngeal papillomas.
Molecular Cloning and Nucleotide Sequence Analysis of a Novel Human Papillomavirus (Type 82) Associated with Vaginal Intraepithelial Neoplasia
Authors: Kino Nao , Sata Tetsutaro , Sato Yuko , Sugase Motoyasu , Matsukura Toshihiko
Published: April 2009

The genome of a novel human papillomavirus (HPV-82) was cloned from a vaginal intraepithelial neoplasia grade I. In our series of 291 biopsy specimens, HPV-82 was identified in one case each of cervical intraepithelial neoplasia grade II and grade III by blot hybridization. The histological localization of HPV-82 DNA in the three lesions was confirmed by in situ hybridization. The results indicated that HPV-82 is an etiologic agent for vaginal and cervical intraepithelial neoplasia. By nucleotide sequence similarity of L1 open reading frame (ORF), HPV-82 was closely related to HPV-26, -51, and -69. To know the precise relationship between the HPVs, we determined the complete sequence of HPV-82, as well as that of HPV-69. Sequencing revealed that the four HPVs had no initiation codon in the E5 ORF and had extensive nucleotide sequence similarities in all ORFs. In addition, they exhibited unique frame position patterns for ORFs, different from those of the other genital HPVs.