bluuebunny/crossref_metadata_2025 huggingface dataset:
Succession of Sulfur-Oxidizing Bacteria in the Microbial Community on Corroding Concrete in Sewer Systems
Authors: Okabe Satoshi , Odagiri Mitsunori , Ito Tsukasa , Satoh Hisashi
Published: December 2006

Microbially induced concrete corrosion (MICC) in sewer systems has been a serious problem for a long time. A better understanding of the succession of microbial community members responsible for the production of sulfuric acid is essential for the efficient control of MICC. In this study, the succession of sulfur-oxidizing bacteria (SOB) in the bacterial community on corroding concrete in a sewer system in situ was investigated over 1 year by culture-independent 16S rRNA gene-based molecular techniques. Results revealed that at least six phylotypes of SOB species were involved in the MICC process, and the predominant SOB species shifted in the following order:
Thiothrix
sp.,
Thiobacillus plumbophilus
,
Thiomonas intermedia
,
Halothiobacillus neapolitanus
,
Acidiphilium acidophilum
, and
Acidithiobacillus thiooxidans. A. thiooxidans
, a hyperacidophilic SOB, was the most dominant (accounting for 70% of EUB338-mixed probe-hybridized cells) in the heavily corroded concrete after 1 year. This succession of SOB species could be dependent on the pH of the concrete surface as well as on trophic properties (e.g., autotrophic or mixotrophic) and on the ability of the SOB to utilize different sulfur compounds (e.g., H
2
S, S
0
, and S
2
O
3
2−
). In addition, diverse heterotrophic bacterial species (e.g., halo-tolerant, neutrophilic, and acidophilic bacteria) were associated with these SOB. The microbial succession of these microorganisms was involved in the colonization of the concrete and the production of sulfuric acid. Furthermore, the vertical distribution of microbial community members revealed that
A. thiooxidans
was the most dominant throughout the heavily corroded concrete (gypsum) layer and that
A. thiooxidans
was most abundant at the highest surface (1.5-mm) layer and decreased logarithmically with depth because of oxygen and H
2
S transport limitations. This suggested that the production of sulfuric acid by
A. thiooxidans
occurred mainly on the concrete surface and the sulfuric acid produced penetrated through the corroded concrete layer and reacted with the sound concrete below.
Inhibition of
Staphylococcus aureus
Growth on Tellurite-Containing Media by
Lactobacillus reuteri
Is Dependent on CyuC and Thiol Production
Authors: Turner Mark S. , Lo Raquel , Giffard Philip M.
Published: December 2006

Lactobacillus reuteri
inhibits
Staphylococcus aureus
growth on Baird-Parker agar. This activity required the presence of tellurite and was not shared with other lactic acid bacteria or an
L. reuteri
mutant defective in cystine metabolism. Secreted products generated from
L. reuteri
cystine metabolism and thiols were shown to augment tellurite toxicity.
Inactivation of a Norovirus by High-Pressure Processing
Authors: Kingsley David H. , Holliman Daniel R. , Calci Kevin R. , Chen Haiqiang , Flick George J.
Published: December 2006

Murine norovirus (strain MNV-1), a propagable norovirus, was evaluated for susceptibility to high-pressure processing. Experiments with virus stocks in Dulbecco's modified Eagle medium demonstrated that at room temperature (20°C) the virus was inactivated over a pressure range of 350 to 450 MPa, with a 5-min, 450-MPa treatment being sufficient to inactivate 6.85 log
10
PFU of MNV-1. The inactivation of MNV-1 was enhanced when pressure was applied at an initial temperature of 5°C; a 5-min pressure treatment of 350 MPa at 30°C inactivated 1.15 log
10
PFU of virus, while the same treatment at 5°C resulted in a reduction of 5.56 log
10
PFU. Evaluation of virus inactivation as a function of treatment times ranging from 0 to 150 s and 0 to 900 s at 5°C and 20°C, respectively, indicated that a decreasing rate of inactivation with time was consistent with Weibull or log-logistic inactivation kinetics. The inactivation of MNV-1 directly within oyster tissues was demonstrated; a 5-min, 400-MPa treatment at 5°C was sufficient to inactivate 4.05 log
10
PFU. This work is the first demonstration that norovirus can be inactivated by high pressure and suggests good prospects for inactivation of nonpropagable human norovirus strains in foods.
An Efficient Fungal RNA-Silencing System Using the
DsRed
Reporter Gene
Authors: Janus Danielle , Hoff Birgit , Hofmann Eckhard , Kück Ulrich
Published: December 2006

In filamentous fungi, RNA silencing is an attractive alternative to disruption experiments for the functional analysis of genes. We adapted the gene encoding the autofluorescent DsRed protein as a reporter to monitor the silencing process in fungal transformants. Using the cephalosporin C producer
Acremonium chrysogenum
, strains showing a high level of expression of the
DsRed
gene were constructed, resulting in red fungal colonies. Transfer of a hairpin-expressing vector carrying fragments of the
DsRed
gene allowed efficient silencing of
DsRed
expression. Monitoring of this process by Northern hybridization, real-time PCR quantification, and spectrofluorometric measurement of the DsRed protein confirmed that downregulation of gene expression can be observed at different expression levels. The usefulness of the DsRed silencing system was demonstrated by investigating cosilencing of
DsRed
together with
pcbC
, encoding the isopenicillin N synthase, an enzyme involved in cephalosporin C biosynthesis. Downregulation of
pcbC
can be detected easily by a bioassay measuring the antibiotic activity of individual strains. In addition, the presence of the isopenicillin N synthase was investigated by Western blot hybridization. All transformants having a colorless phenotype showed simultaneous downregulation of the
pcbC
gene, albeit at different levels. The RNA-silencing system presented here should be a powerful genetic tool for strain improvement and genome-wide analysis of this biotechnologically important filamentous fungus.
Reduced Folate Supply as a Key to Enhanced
l
-Serine Production by
Corynebacterium glutamicum
Authors: Stolz Michael , Peters-Wendisch Petra , Etterich Helga , Gerharz Tanja , Faurie Robert , Sahm Hermann , Fersterra Holger , Eggeling Lothar
Published: December 2006

The amino acid
l
-serine is required for pharmaceutical purposes, and the availability of a sugar-based microbial process for its production is desirable. However, a number of intracellular utilization routes prevent overproduction of
l
-serine, with the essential serine hydroxymethyltransferase (SHMT) (
glyA
) probably occupying a key position. We found that constructs of
Corynebacterium glutamicum
strains where chromosomal
glyA
expression is dependent on P

tac

and
lacI
Q
are unstable, acquiring mutations in
lacI
Q
, for instance. To overcome the inconvenient
glyA
expression control, we instead considered controlling SHMT activity by the availability of 5,6,7,8-tetrahydrofolate (THF). The
pabAB
and
pabC
genes of THF synthesis were identified and deleted in
C. glutamicum
, and the resulting strains were shown to require folate or 4-aminobenzoate for growth. Whereas the
C. glutamicum
Δ
sdaA
strain (p
serACB
) accumulates only traces of
l
-serine, with the
C. glutamicum
Δ
pabABC
Δ
sdaA
strain (p
serACB
),
l
-serine accumulation and growth responded in a dose-dependent manner to an external folate supply. At 0.1 mM folate, 81 mM
l
-serine accumulated. In a 20-liter controlled fed-batch culture, a 345 mM
l
-serine accumulation was achieved. Thus, an efficient and highly competitive process for microbial
l
-serine production is available.
Microbial Community Structure and Dynamics of Dark Fire-Cured Tobacco Fermentation
Authors: Di Giacomo Michele , Paolino Marianna , Silvestro Daniele , Vigliotta Giovanni , Imperi Francesco , Visca Paolo , Alifano Pietro , Parente Dino
Published: December 2006

The Italian Toscano cigar production includes a fermentation step that starts when dark fire-cured tobacco leaves are moistened and mixed with ca. 20% prefermented tobacco to form a 500-kg bulk. The dynamics of the process, lasting ca. 18 days, has never been investigated in detail, and limited information is available on microbiota involved. Here we show that Toscano fermentation is invariably associated with the following: (i) an increase in temperature, pH, and total microbial population; (ii) a decrease in reducing sugars, citric and malic acids, and nitrate content; and (iii) an increase in oxalic acid, nitrite, and tobacco-specific nitrosamine content. The microbial community structure and dynamics were investigated by culture-based and culture-independent approaches, including denaturing gradient gel electrophoresis and single-strand conformational polymorphism. Results demonstrate that fermentation is assisted by a complex microbial community, changing in structure and composition during the process. During the early phase, the moderately acidic and mesophilic environment supports the rapid growth of a yeast population predominated by
Debaryomyces hansenii
. At this stage,
Staphylococcaceae
(
Jeotgalicoccus
and
Staphylococcus
) and
Lactobacillales
(
Aerococcus
,
Lactobacillus
, and
Weissella
) are the most commonly detected bacteria. When temperature and pH increase, endospore-forming low-G+C content gram-positive bacilli (
Bacillus
spp.) become evident. This leads to a further pH increase and promotes growth of moderately halotolerant and alkaliphilic
Actinomycetales
(
Corynebacterium
and
Yania
) during the late phase. To postulate a functional role for individual microbial species assisting the fermentation process, a preliminary physiological and biochemical characterization of representative isolates was performed.
Prenylation of
Saccharomyces cerevisiae
Chs4p Affects Chitin Synthase III Activity and Chitin Chain Length
Authors: Grabińska Kariona A. , Magnelli Paula , Robbins Phillips W.
Published: December 2006

Chs4p (Cal2/Csd4/Skt5) was identified as a protein factor physically interacting with Chs3p, the catalytic subunit of chitin synthase III (CSIII), and is indispensable for its enzymatic activity in vivo. Chs4p contains a putative farnesyl attachment site at the C-terminal end (CVIM motif) conserved in Chs4p of
Saccharomyces cerevisiae
and other fungi. Several previous reports questioned the role of Chs4p prenylation in chitin biosynthesis. In this study we reinvestigated the function of Chs4p prenylation. We provide evidence that Chs4p is farnesylated by showing that purified Chs4p is recognized by anti-farnesyl antibody and is a substrate for farnesyl transferase (FTase) in vitro and that inactivation of FTase increases the amount of unmodified Chs4p in yeast cells. We demonstrate that abolition of Chs4p prenylation causes a ∼60% decrease in CSIII activity, which is correlated with a ∼30% decrease in chitin content and with increased resistance to the chitin binding compound calcofluor white. Furthermore, we show that lack of Chs4p prenylation decreases the average chain length of the chitin polymer. Prenylation of Chs4p, however, is not a factor that mediates plasma membrane association of the protein. Our results provide evidence that the prenyl moiety attached to Chs4p is a factor modulating the activity of CSIII both in vivo and in vitro.
Family Shuffling of Soil DNA To Change the Regiospecificity of
Burkholderia xenovorans
LB400 Biphenyl Dioxygenase
Authors: Vézina Julie , Barriault Diane , Sylvestre Michel
Published: December 2006

Previous work has shown that the C-terminal portion of BphA, especially two amino acid segments designated region III and region IV, influence the regiospecificity of the biphenyl dioxygenase (BPDO) toward 2,2′-dichlorobiphenyl (2,2′-CB). In this work, we evolved BPDO by shuffling
bphA
genes amplified from polychlorinated biphenyl-contaminated soil DNA. Sets of approximately 1-kb DNA fragments were amplified with degenerate primers designed to amplify the C-terminal portion of
bphA
. These fragments were shuffled, and the resulting library was used to replace the corresponding fragment of
Burkholderia xenovorans
LB400
bphA.
Variants were screened for their ability to oxygenate 2,2′-CB onto carbons 5 and 6, which are positions that LB400 BPDO is unable to attack. Variants S100, S149, and S151 were obtained and exhibited this feature. Variant S100 BPDO produced exclusively
cis
-5,6-dihydro-5,6-dihydroxy-2,2′-dichlorobiphenyl from 2,2′-CB. Moreover, unlike LB400 BPDO, S100 BphA catalyzed the oxygenation of 2,2′,3,3′-tetrachlorobiphenyl onto carbons 5 and 6 exclusively and it was unable to oxygenate 2,2′,5,5′-tetrachlorobiphenyl. Based on oxygen consumption measurements, variant S100 oxygenated 2,2′-CB at a rate of 16 ± 1 nmol min
−1
per nmol enzyme, which was similar to the value observed for LB400 BPDO.
cis
-5,6-Dihydro-5,6-dihydroxy-2,2′-dichlorobiphenyl was further oxidized by 2,3-dihydro-2,3-dihydroxybiphenyl dehydrogenase (BphB) and 2,3-dihydroxybiphenyl dioxygenase (BphC). Variant S100 was, in addition, able to oxygenate benzene, toluene, and ethyl benzene. Sequence analysis identified amino acid residues M
237
S
238
and S
283
outside regions III and IV that influence the activity toward doubly
ortho
-substituted chlorobiphenyls.
Proteome and Differential Expression Analysis of Membrane and Cytosolic Proteins from
Mycobacterium avium
subsp.
paratuberculosis
Strains K-10 and 187
Authors: Radosevich Thomas J. , Reinhardt Timothy A. , Lippolis John D. , Bannantine John P. , Stabel Judith R.
Published: December 2006

Little is known of protein expression in
Mycobacterium avium
subsp.
paratuberculosis
and how this contributes to pathogenesis. In the present study, proteins from both membranes and cytosol were prepared from two strains of
M. avium
subsp.
paratuberculosis
, i.e., laboratory-adapted strain K-10 and a recent isolate, strain 187, obtained from a cow exhibiting clinical signs of Johne's disease. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of cytosol and membrane proteins from K-10 and 187 showed marked differences in protein expression. Relative levels of protein expression from both
M. avium
subsp.
paratuberculosis
strains were measured by using amine-reactive isobaric tagging reagents (iTRAQ) and tandem mass spectroscopy. Protein identification and relative expression data were obtained for 874 membrane and cytosolic proteins from the
M. avium
subsp.
paratuberculosis
proteome. These data showed a number of significant differences in protein expression between strain K-10 and clinical isolate 187. Examples of proteins expressed at higher levels in clinical isolate 187 compared to strain K-10 are AtpC, RpoA, and several proteins involved in fatty acid biosynthesis. In contrast, proteins such as AhpC and several proteins involved in nitrogen metabolism were expressed at higher levels in strain K-10 compared to strain 187. These data may provide insights into the proteins whose expression is important in natural infection but are modified once
M. avium
subsp.
paratuberculosis
is adapted to laboratory cultivation. Results from these studies will provide tools for developing a better understanding of
M. avium
subsp.
paratuberculosis
infection in the host and offer potential as diagnostic reagents and vaccine candidates.
Expression of the Major Porin Gene
mspA
Is Regulated in
Mycobacterium smegmatis
Authors: Hillmann Dietmar , Eschenbacher Iris , Thiel Anja , Niederweis Michael
Published: December 2006

MspA is the major porin of
Mycobacterium smegmatis
and is important for diffusion of small and hydrophilic solutes across its unique outer membrane. The start point of transcription of the
mspA
gene was mapped by primer extension and S1 nuclease experiments. The main promoter driving transcription of
mspA
was identified by single point mutations in
lacZ
fusions and resembled σ
A
promoters of
M. smegmatis
. However, a 500-bp upstream fragment including P

mspA

in a transcriptional fusion with
lacZ
yielded only low β-galactosidase activity, whereas activity increased 12-fold with a 700-bp fragment. Activation of P

mspA

by the 200-bp element was almost eliminated by increasing the distance by 14 bp, indicating binding of an activator protein. The chromosomal
mspA
transcript had a size of 900 bases and was very stable with a half-life of 6 minutes, whereas the stabilities of episomal
mspA
transcripts with three other 5′ untranslated region (UTRs) were three- to sixfold reduced, indicating a stabilizing role of the native 5′ UTR of
mspA
. Northern blot experiments revealed that the amount of
mspA
mRNA was increased under nitrogen limitation but reduced under carbon and phosphate limitation at 42°C in stationary phase in the presence of 0.5 M sodium chloride, 18 mM hydrogen peroxide, and 10% ethanol and at acidic pH. These results show for the first time that
M. smegmatis
regulates porin gene expression to optimize uptake of certain nutrients and to protect itself from toxic solutes.
A Second Galacturonic Acid Transferase Is Required for Core Lipopolysaccharide Biosynthesis and Complete Capsule Association with the Cell Surface in
Klebsiella pneumoniae
Authors: Fresno Sandra , Jiménez Natalia , Canals Rocío , Merino Susana , Corsaro Maria Michela , Lanzetta Rosa , Parrilli Michelangelo , Pieretti Giuseppina , Regué Miguel , Tomás Juan M.
Published: December 2006

The core lipopolysaccharide (LPS) of
Klebsiella pneumoniae
contains two galacturonic acid (GalA) residues, but only one GalA transferase (WabG) has been identified. Data from chemical and structural analysis of LPS isolated from a
wabO
mutant show the absence of the inner core β-GalA residue linked to
l
-
glycero
-
d
-
manno
-heptose III (
l
,
d
-Hep III). An in vitro assay demonstrates that the purified WabO is able to catalyze the transfer of GalA from UDP-GalA to the acceptor LPS isolated from the
wabO
mutant, but not to LPS isolated from
waaQ
mutant (deficient in
l
,
d
-Hep III). The absence of this inner core β-GalA residue results in a decrease in virulence in a capsule-dependent experimental mouse pneumonia model. In addition, this mutation leads to a strong reduction in cell-bound capsule. Interestingly, a K66
Klebsiella
strain (natural isolate) without a functional
wabO
gene shows reduced levels of cell-bound capsule in comparison to those of other K66 strains. Thus, the WabO enzyme plays an important role in core LPS biosynthesis and determines the level of cell-bound capsule in
Klebsiella pneumoniae
.
A Stochastic Mechanism for Biofilm Formation by
Mycoplasma pulmonis
Authors: Simmons Warren L. , Bolland Jeffrey R. , Daubenspeck James M. , Dybvig Kevin
Published: December 2006

Bacterial biofilms are communities of bacteria that are enclosed in an extracellular matrix. Within a biofilm the bacteria are protected from antimicrobials, environmental stresses, and immune responses from the host. Biofilms are often believed to have a highly developed organization that is derived from differential regulation of the genes that direct the synthesis of the extracellular matrix and the attachment to surfaces. The mycoplasmas have the smallest of the prokaryotic genomes and apparently lack complex gene-regulatory systems. We examined biofilm formation by
Mycoplasma pulmonis
and found it to be dependent on the length of the tandem repeat region of the variable surface antigen (Vsa) protein. Mycoplasmas that produced a short Vsa protein with few tandem repeats formed biofilms that attached to polystyrene and glass. Mycoplasmas that produced a long Vsa protein with many tandem repeats formed microcolonies that floated freely in the medium. The biofilms and the microcolonies contained an extracellular matrix which contained Vsa protein, lipid, DNA, and saccharide. As variation in the number of Vsa tandem repeats occurs by slipped-strand mispairing, the ability of the mycoplasmas to form a biofilm switches stochastically.
Anionic Lipids Enriched at the ExPortal of
Streptococcus pyogenes
Authors: Rosch Jason W. , Hsu Fong Fu , Caparon Michael G.
Published: December 2006

The ExPortal of
Streptococcus pyogenes
is a membrane microdomain dedicated to the secretion and folding of proteins. We investigated the lipid composition of the ExPortal by examining the distribution of anionic membrane phospholipids. Staining with 10-
N
-nonyl-acridine orange revealed a single microdomain enriched with an anionic phospholipid whose staining characteristics and behavior in a cardiolipin-deficient mutant were characteristic of phosphatidylglycerol. Furthermore, the location of the microdomain corresponded to the site of active protein secretion at the ExPortal. These results indicate that the ExPortal is an asymmetric lipid microdomain, whose enriched content of anionic phospholipids may play an important role in ExPortal organization and protein trafficking.
Role of Phosphoenolpyruvate in the NADP-Isocitrate Dehydrogenase and Isocitrate Lyase Reaction in
Escherichia coli
Authors: Ogawa Tadashi , Murakami Keiko , Mori Hirotada , Ishii Nobuyoshi , Tomita Masaru , Yoshin Masataka
Published: December 2006

Phosphoenolpyruvate inhibited
Escherichia coli
NADP-isocitrate dehydrogenase allosterically (

K
i

of 0.31 mM) and isocitrate lyase uncompetitively (

K
i

′ of 0.893 mM). Phosphoenolpyruvate enhances the uncompetitive inhibition of isocitrate lyase by increasing isocitrate, which protects isocitrate dehydrogenase from the inhibition, and contributes to the control through the tricarboxylic acid cycle and glyoxylate shunt.
Syncope due to Brugada syndrome in a young athlete
Authors: Esperer Hans D , Hoos Olaf , Hottenrott Kuno
Published: December 2006

A 30-year-old male athlete with exercise-related syncopal symptoms spontaneously exhibited a type 1 Brugada ECG and was inducible during electrophysiology study. He was diagnosed with symptomatic Brugada syndrome and deemed at high risk of sudden cardiac death. Thus, he received a cardioverter/defibrillator and was advised to abstain from further competitive sports activities. This case points to a role of the ECG in pre-participation screening. It also demonstrates that, in athletes with Brugada syndrome, repolarisation anomalies may be markedly attenuated during vigorous exercise and considerably increased immediately after exercise. The observed J-wave amplitude dynamics suggests enhancement of pre-existing autonomic dysfunction through heavy exertion.
Haemodynamic changes induced by submaximal exercise before a dive and its consequences on bubble formation
Authors: Blatteau Jean-Eric , Boussuges Alain , Gempp Emmanuel , Pontier Jean-Michel , Castagna Olivier , Robinet Claude , Galland Francois-Michel , Bourdon Lionel
Published: December 2006

Objectives:To evaluate the effects of a submaximal exercise performed 2 h before a simulated dive on bubble formation and to observe the haemodynamic changes and their influence on bubble formation.

Participants and methods:16 trained divers were compressed in a hyperbaric chamber to 400 kPa for 30 min and decompressed at a rate of 100 kPa/min with a 9 min stop at 130 kPa (French Navy MN90 procedure). Each diver performed two dives 3 days apart, one without exercise and one with exercise before the dive. All participants performed a 40 min constant-load submaximal and calibrated exercise, which consisted of outdoor running 2 h before the dive. Circulating bubbles were detected with a precordial Doppler at 30, 60 and 90 min after surfacing. Haemodynamic changes were evaluated with Doppler echocardiography.

Results:A single bout of strenuous exercise 2 h before a simulated dive significantly reduced circulating bubbles. Post-exercise hypotension (PEH) was observed after exercise with reductions in diastolic and mean blood pressure (DBP and MBP), but total peripheral resistance was unchanged. Stroke volume was reduced, whereas cardiac output was unchanged. Simulated diving caused a similar reduction in cardiac output independent of pre-dive exercise, suggesting that pre-dive exercise only changed DBP and MBP caused by reduced stroke volume.

Conclusion:A single bout of strenuous exercise 2 h before a dive significantly reduced the number of bubbles in the right heart of divers and protected them from decompression sickness. Declining stroke volume and moderate dehydration induced by a pre-dive exercise might influence inert gas load and bubble formation.
Injuries in amateur horse racing (point to point racing) in Great Britain and Ireland during 1993–2006
Authors: Balendra Ganesh , Turner Michael , McCrory Paul , Halley Walter
Published: December 2006

Objectives:To provide a breakdown of injury incidence from amateur jump racing (also known as point to point racing) in Great Britain and Ireland during 1993–2006 and to compare the injury epidemiology with professional horse racing in Great Britain, Ireland and France.

Design:Retrospective review.

Setting:Great Britain and Ireland.

Participants:Amateur jockeys.

Main outcome measures:Injury rates.

Results:Injury data suggest that point to point racing is more dangerous from an injury point of view than professional jump racing, which has previously been shown to be more dangerous than flat racing. Amateur jockeys have more falls than their professional counterparts, and this in turn puts them at greater risk of sustaining more serious injuries.

Conclusions:Amateur (point to point) jockeys represent a sporting population that previously has been little studied. They represent a group at high risk of injury, and hence formal injury surveillance tracking and counter measures for injury prevention are recommended.
Parvovirus B19 detected in Rosai–Dorfman disease in nodal and extranodal manifestations
Authors: Mehraein Y , Wagner M , Remberger K , Füzesi L , Middel P , Kaptur S , Schmitt K , Meese E
Published: December 2006

Sinus histiocytosis with massive lymphadenopathy (SHML), also designated as Rosai–Dorfman disease (RDD), is a rare benign reactive lymphoproliferative disorder. It is defined by a characteristic histopathology with sinus histiocytosis and haemophagocytosis known as emperipolesis. In histiocytes S100 is strongly expressed, whereas CD1a staining typically is negative. The disease mainly manifests at a single lymph node; however, multilocular and extranodal affection can occur. Causative infectious agents, and virus infections in particular, have repeatedly been suspected, although until now the origin of the disease has been unclear. Four cases of RDD (two nodal sites and two extranodal upper respiratory tract sites) were analysed for parvovirus B19 (B19) infection by immunohistochemistry to detect B19 capsid proteins VP1/VP2. In all the four cases, huge numbers of B19-positive cells were partly detected. The positive cells were identified either as lymphocytes or, in one extranodal case, also as respiratory epithelial cells. This is the first report of B19 infection in RDD tissue, indicating that B19 may be associated with the pathogenesis of SHML.
Herpetiform cutaneous metastases from transitional cell carcinoma of the urinary bladder: immunohistochemical analysis
Authors: Somani B K , Prita D , Grant S , Nabi G , N’Dow J
Published: December 2006

The case of an 83-year-old woman with an uncommon presentation of cutaneous metastases from muscle-invasive transitional cell carcinoma of the urinary bladder is reported. The band-like eruption of the metastatic lesion can often be misdiagnosed and treated initially as herpes zoster. A detailed immunohistochemical analysis is also described to differentiate metastatic lesions from other sources.
Use of assessment to reinforce patient safety as a habit:
Figure 1
Authors: Galbraith R M , Holtman M C , Clyman S G
Published: December 2006

The US spends far more than any other nation on health care. Physicians undergo lengthy and comprehensive training that is carefully scrutinized, and are held to high standards in national examinations. At best the care delivered matches or exceeds that in any other country. And yet, often simple preventable medical errors occur at alarming and unacceptable rates. The public, corporate consumers of health care, large payors and malpractice insurance carriers are all becoming impatient with the pace of improvement. The medical profession recognizes that dealing with this problem is an urgent priority and is grappling to find the best approaches. This paper focuses on the constructive use of assessment to embed a pervasive and proactive culture of patient safety into practice, starting with the trainee and extending out into the practice years. This strategy is based on the adage that “assessment drives curriculum” and proposes a series of new assessment tools to be added to all phases of the training-practice continuum.
Why did that happen? Exploring the proliferation of barely usable software in healthcare systems
Authors: Johnson C W
Published: December 2006

Clinicians and support staff are faced with increasingly complex computer applications. This complexity stems partly from the integration of heterogeneous systems ranging from computerized patient records to theatre management and dosage planning applications, and also from the increased functionality offered by the new generation of IT systems. Many members of clinical staff are bewildered by the vast array of configuration options and operating modes supported by computer based systems, while manufacturers often feel compelled to offer more and more software features to retain market position. These factors combine to create “usability” problems that have had a direct impact on patient outcomes as well as a number of indirect effects—for example, the costs of replacing and upgrading inadequate computer systems carry significant opportunity costs in terms of services that might otherwise have been funded. In the future we need to educate staff to reject substandard computer interfaces early in the acquisition process; encourage the use of human computer interaction techniques in health care; and train staff to recognize the dangers of “working around” poor interface design.
Mechanism of cyclopropanol to cyclopropanol isomerization mediated by Ti(IV) and a Lewis acid
Authors: Casey Charles P , Strotman Neil A
Published: December 2006

Isomerization of trans-3-deutero-r-1-methyl-cis-2-phenylcyclopropan-1-ol (1-trans-d) to three isomeric cyclopropanols was facilitated by reaction with a mixture of Ti(O-i-Pr)4 and BF3·OEt2. The more Lewis acidic Cl2Ti(O-i-Pr)2 catalyzed this reaction in the absence of BF3·OEt2. This cyclopropanol to cyclopropanol rearrangement involves reversible ring opening to a β-titanaketone. When the major species in solution prior to quenching was a titanium cyclopropoxide, a 40:40:10:10 mixture of cyclopropanols 1-trans-d:1-cis-d:2-trans-d:2-cis-d was obtained; this is close to the equilibrium ratio of the titanium cyclopropoxides. When a catalytic quantity of Ti(O-i-Pr)4 and a large excess of cyclopropanol was used, quenching gave a 29:29:21:21 mixture; this is closer to the equilibrium ratio of the cyclopropanols than the cyclopropoxides. Extrapolation to 0% and to 100% cyclopropoxide gave equilibrium constants for both cyclopropanols (Keq = [2]/[1] = 1.3) and cyclopropoxides (Keq = [2-Ti]/[1-Ti] = 0.18). A mechanism for these isomerization processes that involves ring opening and (or) ring closing with both retention and inversion of configuration at the carbon bearing phenyl is proposed.Key words: cyclopropanol, titanium isopropoxide, Kulinkovich hydroxycyclopropanation.
Synthesis of a hindered C2-symmetric hydrazine and diamine by a crisscross cycloaddition of citronellal azine
Authors: Snider Barry B , Grabowski James F , Alder Roger W , Foxman Bruce M , Yang Lin
Published: December 2006

Crisscross cycloaddition of citronellal azine (6) with 2 equiv. of TFA and powdered 3 Å molecular sieves in CH2Cl2 at reflux for 22 h afforded 37% of the desired C2-symmetric hydrazine 7 and 5%–10% of diastereomer 8 in which one of the 6–5 ring fusions is cis. Methylation of the hydrazine of 7 and reduction of the resulting salt (9) with Li in NH3 cleaved the N—N bond to give secondary tertiary amine 10 in 97% yield. Eschweiler–Clarke methylation afforded the C2-symmetric bis tertiary amine 11 in 69% yield. Racemic products were obtained in initial attempts at asymmetric catalysis using 7 or 11 as asymmetric bases, using bistertiary amine 11 as a ligand analogous to sparteine for alkyllithiums, or using the lithium amide from secondary tertiary amine 10 as an asymmetric base. Apparently, the proton is buried in the core of 11, leaving a hydrophobic surface; the free counterion is not an asymmetric catalyst. Diamine 11 may be too hindered to complex to s-BuLi. Tertiary amine 11 (pKa1 = 24.7) is more basic than DBU (pKa = 24.3) in CH3CN, in good agreement with theory.Key words: crisscross cycloaddition, azine, dipolar cycloaddition, calculation of pKa.
Bis(ether) derivatives of tetrakis(2-hydroxyphenyl)ethene — Direct synthesis of (E)- and (Z)-bis(2-hydroxyphenyl)-bis(2-methoxyphenyl)ethene via the McMurry olefination reaction
Authors: Chung Mee-Kyung , Fancy Paul , Stryker Jeffrey M
Published: December 2006

The direct synthesis of sterically hindered, partially etherified derivatives of tetrakis(2-hydroxyphenyl)ethene is reported by using the McMurry reductive olefination reaction on a range of differentially substituted 2,2′-dialkoxy benzophenone substrates. Three orthogonal protection strategies are demonstrated, incorporating β-silylethyl, 3-butenyl, and tert-butyl protecting groups, respectively, into the starting benzophenones. The latter proved most efficient, with both the McMurry coupling and deprotection steps occurring concomitantly under the McMurry conditions to directly yield the desired bis(2-hydroxyphenyl)-bis(2-methoxyphenyl)ethene as a 1:1 mixture of E- and Z-diastereoisomers.Key words: preorganized polyaryloxide ligands, McMurry olefination, titanium trichloride, supramolecular chemistry, tetrakis(2-hydroxyphenyl)ethene, 2,2′-disubstituted benzophenone.
Synthesis of an 11-cis-locked biotinylated retinoid for sequestering 11-cis-retinoid binding proteins
Authors: Matsuda Hiroko , Zhang Shenglong , Holmes Andrea E , Krane Sonja , Itagaki Yasuhiro , Nakanishi Koji , Nesnas Nasri
Published: December 2006

The synthesis of a seven-membered ring locked analogue of 11-cis-retinol, tethered to a cross-linking moiety on C-15 and a lysine-extended biotin on the C-3, was accomplished for its utilization as a probe to fish out retinol binding proteins that may be involved in the reisomerization of retinal from all-trans to 11-cis in the visual cycle.Key words: retinoids, biotin, 11-cis-locked, cross-linking, retinol binding proteins.
Synthesis and characterization of 2,7-bis(2-pyridyl)-1,8-diazaanthraquinone — A redox-active ligand designed for the construction of supramolecular grids
Authors: Jain Rajsapan , Caldwell Sharon L , Louie Anika S , Hicks Robin G
Published: December 2006

Double condensation of 2-acetylpyridine with 1,3-diaminobenzene-4,6-dicarboxaldehyde affords 2,7-bis(2-pyridyl)-1,8-diazaanthracene, which was subsequently oxidized to the corresponding quinone. Electrochemical studies indicate two reversible reduction processes corresponding to semiquinone and hydroquinonate formation. Electron-withdrawing pyridine groups and the nitrogen atoms make this somewhat more easily reduced than anthraquinone. This compound is redox-active and can be reduced to its radical anion, a potential spin-bearing ligand for the construction of [2 × 2] metallo-grid structures.Key words: quinone, grid, supramolecular, bistridentate, electrochemistry, metallosupramolecular chemistry.
Syntheses and characterization of phthalonitriles and phthalocyanines substituted with adamantane moieties
Authors: Causey Patrick W , Dubovyk Igor , Leznoff Clifford C
Published: December 2006

The reaction of 3,4,5,6-tetrafluorophthalonitrile with 1-adamantanol, 1-adamantylamine, 1-adamantanemethanol, and 1-adamantaneethanol gave 4,5-di-(1-adamantyloxy)-3,6-difluorophthalonitrile, 4,5-di-(1-adamantylamino)-3,6-difluorophthalonitrile, 4-(1-adamantylamino)-3,5,6-trifluorophthalonitrile, 3,4,5,6-tetra-(1-adamantylmethoxy)phthalonitrile, and 3,4,5,6-tetra-(1-adamantylethoxy)phthalonitrile, respectively. The conversion of these tetrasubstituted phthalonitriles to magnesium, nickel, and metal-free phthalocyanines was demonstrated. These highly hindered phthalocyanines exhibited interesting red shifts in their UV–vis spectra.Key words: highly hindered adamantane phthalocyanines, adamantylphthalonitriles.
Synthesis and Lewis acid induced isomerization of mono-, di-, and tri-spiro α-keto tetrahydro-furans and -pyrans
Authors: Hilmey David G , Selvaraj Peter R , Paquette Leo A
Published: December 2006

The stereoselectivity of the acid-catalyzed ring expansion of dihydrofuranyl and dihydropyranyl 1,2-adducts to spirocyclic ketones 8 and 9 has been examined. These substrates have become readily available by the utilization of 1,3-dichloroacetone as a synthetic equivalent of cyclopropanone. The kinetically controlled isomerizations result in ring expansion to dispirocyclopentanones. Third-stage conversion to trispirocyclohexanones was shown to be possible in select examples. On a different front, the syn and anti pairs proved capable of interconversion by heating in the presence of boron trifluoride etherate. A push–pull fragmentation of the ketone ring is proposed to account for these epimerizations. Calculations have been performed to simulate transition state energies in the oxonium ion intermediates and to gain some idea of the preferred ground-state geometries of the final products.Key words: oxonium ion rearrangements, ring expansions, acid-catalyzed epimerizations, cyclopropanone equivalent, spirocyclic ethers.
An examination of VANOL, VAPOL, and VAPOL derivatives as ligands for asymmetric catalytic Diels–Alder reactions
Authors: Heller Douglas P , Goldberg Daniel R , Wu Hongqiao , Wulff William D
Published: December 2006

Several derivatives of the vaulted biaryl ligand VAPOL were prepared and evaluated as chiral ligands for aluminum Lewis acids in the catalytic asymmetric Diels–Alder reactions of methyl acrylate and methacrolein with cyclopentadiene. The substituents on VAPOL were introduced into the 6- and 6′-positions in an effort to further extend the chiral pocket of the major groove, which contains the phenol functions at the 4- and 4′-positions. The set of four new ligands that have been prepared have the following groups introduced into the 6- and 6′-positions of VAPOL: bromide, methyl, phenyl and 3,5-di-t-butylphenyl. All of these ligands give lower asymmetric inductions than the unsubstituted VAPOL for the Diels–Alder reactions of both methyl acrylate and methacrolein. The positive cooperativity of added carbonyl compounds on the autoinduction in the Diels–Alder reaction of methyl acrylate and cyclopentadiene were also investigated with the VANOL and VAPOL ligands as well as the 6,6′-dibromo and 6,6′-diphenyl derivatives of VAPOL. Only the reaction with VAPOL showed any significant positive cooperativity. The reaction with VANOL was sluggish at –78 °C, but at higher temperatures, the reaction did exhibit positive cooperativity that was similar to that of VAPOL. Finally, no positive cooperativity was observed with the VAPOL ligand for the reaction of methacrolein and cyclopentadiene.Key words: Diels–Alder, asymmetric catalysis, vaulted biaryl ligands, VANOL, VAPOL.
Morphology of surfactant–polymer complexes on mica substrate visualized by atomic force microscopy
Authors: Zhao Feng , Du Yukou , Xu Jingkun , Liu Shufeng
Published: December 2006

The morphology of surfactant–polymer complexes formed in two dimensions has been studied. We found that the morphology of hexadecyltrimethylammonium bromide – modified partially hydrated polyacrylamide (CTAB–MHPAM) complexes transferred to mica from the interface between air and MHPAM aqueous solution shows pearl necklace structures, and it is orientationally aligned. On the addition of salt, this structure is altered to the dendritic fractal structure with a smaller fractal dimension about 1.1 ± 0.01. These structures have potential applications in the fabrication of materials in the nanoscale. The mechanism of the formation of different patterns has been discussed.Key words: morphology, Surfactant–polymer complexes, Dendritic fractal structure.
Metal(II) Schiff base complexes as catalysts for the high-regioselective conversion of epoxides to β-hydroxy nitriles in glycol solvents
Authors: Naeimi Hossein , Moradian Mohsen
Published: December 2006

A facile preparation of 3-hydroxy propanenitrile derivatives is described involving ring opening of epoxides with potassium cyanide in glycol solvents in the presence of Schiff base complexes as catalysts. This method occurs under neutral and mild conditions with high yields and high regioselectivity. Thus, several β-Hydroxy nitriles, useful intermediates toward biologically-active molecules, are easily obtained at room temperature.Key words: β-hydroxy nitrile, Schiff base, epoxide, glycol, catalyst.
Ytterbium perfluorooctanesulfonate catalyzed synthesis of acylals from aldehydes and acetic anhydride in a fluorous biphasic system
Authors: Yi Wen-Bin , Yin Ya-Qing , Cai Chun
Published: December 2006

Ytterbium perfluorooctanesulfonate [Yb(OPf)3] catalyses the highly efficient synthesis of acylals from aldehydes and acetic anhydride in a fluorous biphase system (FBS) composed of toluene and perfluorodecalin. The fluorous phase containing the fluorous catalyst is easily separated and can be reused several times without significant loss of catalytic activity.Key words: acylals, ytterbium perfluorooctanesulfonate, fluorous biphasic catalysis.
SIMD MULTIPLIERS FOR ACCELERATING EMBEDDED PROCESSORS IN FPGAs
Authors: PERRI STEFANIA , IACHINO MARIA ANTONIA , CORSONELLO PASQUALE
Published: December 2006

This paper describes a new efficient 32×32 Single Instruction Multiple Data (SIMD) multiplier suitable for the multimedia extension of FPGA-based processors. The proposed circuit can adapt itself to 32-, 16-, and 8-bit operands widths avoiding time and power consuming reconfiguration. When implemented in an XCV400 device, the multiplier here described reaches a running frequency of about 97 MHz with an energy dissipation of just 20 mW/MHz. Comparisons with previously proposed SIMD multipliers for FPGA-based designs demonstrate that the new circuit allows the best area-time-power trade-off to be obtained.
Organized migration of epithelial cells requires control of adhesion and protrusion through Rho kinase effectors
Authors: Hopkins Ann M. , Pineda A’Drian A. , Winfree L. Matthew , Brown G. Thomas , Laukoetter Mike G. , Nusrat Asma
Published: December 2006

Migration of epithelial cell sheets, a process involving F-actin restructuring through Rho family GTPases, is both physiologically and pathophysiologically important. Our objective was to clarify the mechanisms whereby the downstream RhoA effector Rho-associated coil-coil-forming kinase (ROCK) influences coordinated epithelial cell motility. Although cells exposed to a pharmacological ROCK inhibitor (Y-27632) exhibited increased spreading in wound closure assays, they failed to migrate in a cohesive manner. Two main phenomena were implicated: the formation of aberrant protrusions at the migrating front and the basal accumulation of F-actin aggregates. Aggregates reflected increased membrane affiliation and detergent insolubility of the actin-binding protein ezrin and enhanced coassociation of ezrin with the membrane protein CD44. While F-actin aggregation following ROCK inhibition was recapitulated by inhibiting myosin light chain (MLC) phosphorylation with the MLC kinase inhibitor ML-7, the latter did not influence protrusiveness and, in fact, significantly decreased cell migration. Our results suggest that excessive protrusiveness downstream of ROCK inhibition reflects an influence of ROCK on F-actin stability via LIM kinase 1 (LIMK-1), which phosphorylates and inactivates cofilin. Y-27632 reduced the levels of both active LIMK-1 and inactive cofilin (phospho forms), and expression of a dominant negative LIMK-1 mutant stimulated leading edge protrusiveness. Furthermore, Y-27632-induced protrusions were partially reversed by overexpression of LIMK-1 to restore cofilin phosphorylation. In summary, our results provide new evidence suggesting that adhesive and protrusive events involved in organized epithelial motility downstream of ROCK are separately coordinated through the phosphorylation of (respectively) MLC and cofilin.
Intestinal ribosomal p70S6Ksignaling is increased in piglet rotavirus enteritis
Authors: Rhoads J. Marc , Corl Benjamin A. , Harrell Robert , Niu Xiaomei , Gatlin Lori , Phillips Oulayvanh , Blikslager Anthony , Moeser Adam , Wu Guoyao , Odle Jack
Published: December 2006

Recent identification of the mammalian target of rapamycin (mTOR) pathway as an amino acid-sensing mechanism that regulates protein synthesis led us to investigate its role in rotavirus diarrhea. We hypothesized that malnutrition would reduce the jejunal protein synthetic rate and mTOR signaling via its target, ribosomal p70 S6 kinase (p70S6K). Newborn piglets were artificially fed from birth and infected with porcine rotavirus on day 5 of life. Study groups included infected (fully fed and 50% protein calorie malnourished) and noninfected fully fed controls. Initially, in “worst-case scenario studies,” malnourished infected piglets were killed on days 1, 3, 5, and 11 postinoculation, and jejunal samples were compared with controls to determine the time course of injury and p70S6Kactivation. Using a 2 × 2 factorial design, we subsequently determined if infection and/or malnutrition affected mTOR activation on day 3. Western blot analysis and immunohistochemistry were used to measure total and phosphorylated p70S6K; [3H]phenylalanine incorporation was used to measure protein synthesis; and lactase specific activity and villus-crypt dimensions were used to quantify injury. At the peak of diarrhea, the in vitro jejunal protein synthetic rate increased twofold (compared with the rate in the uninfected pig jejunum), concomitant with increased jejunal p70S6Kphosphorylation (4-fold) and an increased p70S6Klevel (3-fold, P < 0.05). Malnutrition did not alter the magnitude of p70S6Kactivation. Immunolocalization revealed that infection produced a major induction of cytoplasmic p70S6Kand nuclear phospho-p70S6K, mainly in the crypt. A downregulation of semitendinosus muscle p70S6Kphosphorylation was seen at days 1–3 postinoculation. In conclusion, intestinal activation of p70S6Kwas not inhibited by malnutrition but was strongly activated during an active state of mucosal regeneration.