bluuebunny/crossref_metadata_2025 huggingface dataset:
Distribution of Genes for Synthesis of Trehalose and Mannosylglycerate in
Thermus
spp. and Direct Correlation of These Genes with Halotolerance
Authors: Alarico Susana , Empadinhas Nuno , Simões Catarina , Silva Zélia , Henne Anke , Mingote Ana , Santos Helena , da Costa Milton S.
Published: May 2005

In this study we correlate the presence of genes leading to the synthesis of trehalose and mannosylglycerate (MG) in 17 strains of the genus
Thermus
with the ability of the strains to grow and accumulate these compatible solutes in a defined medium containing NaCl. The two sets of genes, namely,
otsA
/
otsB
for the synthesis of trehalose and
mpgS
/
mpgP
for the synthesis of MG, were necessary for the growth of
Thermus thermophilus
in a defined medium containing up to 6% NaCl. Strains lacking a complete
otsA
gene did not grow in defined medium containing >2% NaCl. One strain of
T. thermophilus
lacking the genes for the synthesis of MG did not grow in a medium with >1% NaCl. We did not identify any of these genes in the type strains of the other seven species of
Thermus
, and none of those strains grew in defined medium with 1% NaCl. The results strongly indicate that the combined accumulation of trehalose and MG is required for optimal osmotic adjustment.
Variation in Acid Resistance among Shiga Toxin-Producing Clones of Pathogenic
Escherichia coli
Authors: Large Teresa M. , Walk Seth T. , Whittam Thomas S.
Published: May 2005

Pathogenic strains of
Escherichia coli
, such as
E. coli
O157:H7, have a low infectious dose and an ability to survive in acidic foods. These bacteria have evolved at least three distinct mechanisms of acid resistance (AR), including two amino acid decarboxylase-dependent systems (arginine and glutamate) and a glucose catabolite-repressed system. We quantified the survival rates for each AR mechanism separately in clinical isolates representing three groups of Shiga toxin-producing
E. coli
(STEC) clones (O157:H7, O26:H11/O111:H8, and O121:H19) and six commensal strains from ECOR group A. Members of the STEC clones were not significantly more acid resistant than the commensal strains when analyzed using any individual AR mechanism. The glutamate system provided the best protection in a highly acidic environment for all groups of isolates (<0.1 log reduction in CFU/ml per hour at pH 2.0). Under these conditions, there was notable variation in survival rates among the 30 O157:H7 strains, which depended in part on Mg
2+
concentration. The arginine system provided better protection at pH 2.5, with a range of 0.03 to 0.41 log reduction per hour, compared to the oxidative system, with a range of 0.13 to 0.64 log reduction per hour. The average survival rate for the O157:H7 clonal group was significantly less than that of the other STEC clones in the glutamate and arginine systems and significantly less than that of the O26/O111 clone in the oxidative system, indicating that this clonal group is not exceptionally acid resistant with these specific mechanisms.
Succession of Internal Sulfur Cycles and Sulfur-Oxidizing Bacterial Communities in Microaerophilic Wastewater Biofilms
Authors: Okabe Satoshi , Ito Tsukasa , Sugita Kenichi , Satoh Hisashi
Published: May 2005

The succession of sulfur-oxidizing bacterial (SOB) community structure and the complex internal sulfur cycle occurring in wastewater biofilms growing under microaerophilic conditions was analyzed by using a polyphasic approach that employed 16S rRNA gene-cloning analysis combined with fluorescence in situ hybridization, microelectrode measurements, and standard batch and reactor experiments. A complete sulfur cycle was established via S
0
accumulation within 80 days in the biofilms in replicate. This development was generally split into two phases, (i) a sulfur-accumulating phase and (ii) a sulfate-producing phase. In the first phase (until about 40 days), since the sulfide production rate (sulfate-reducing activity) exceeded the maximum sulfide-oxidizing capacity of SOB in the biofilms, H
2
S was only partially oxidized to S
0
by mainly
Thiomicrospira denitirificans
with NO
3
−
as an electron acceptor, leading to significant accumulation of S
0
in the biofilms. In the second phase, the SOB populations developed further and diversified with time. In particular, S
0
accumulation promoted the growth of a novel strain, strain SO07, which predominantly carried out the oxidation of S
0
to SO
4
2−
under oxic conditions, and
Thiothrix
sp. strain CT3. In situ hybridization analysis revealed that the dense populations of
Thiothrix
(ca. 10
9
cells cm
−3
) and strain SO07 (ca. 10
8
cells cm
−3
) were found at the sulfur-rich surface (100 μm), while the population of
Thiomicrospira denitirificans
was distributed throughout the biofilms with a density of ca. 10
7
to 10
8
cells cm
−3
. Microelectrode measurements revealed that active sulfide-oxidizing zones overlapped the spatial distributions of different phylogenetic SOB groups in the biofilms. As a consequence, the sulfide-oxidizing capacities of the biofilms became high enough to completely oxidize all H
2
S produced by SRB to SO
4
2−
in the second phase, indicating establishment of the complete sulfur cycle in the biofilms.
New Resistance Mechanism in
Helicoverpa armigera
Threatens Transgenic Crops Expressing
Bacillus thuringiensis
Cry1Ac Toxin
Authors: Gunning Robin V. , Dang Ho T. , Kemp Fred C. , Nicholson Ian C. , Moores Graham D.
Published: May 2005

In Australia, the cotton bollworm,
Helicoverpa armigera
, has a long history of resistance to conventional insecticides. Transgenic cotton (expressing the
Bacillus thuringiensis
toxin Cry1Ac) has been grown for
H. armigera
control since 1996. It is demonstrated here that a population of Australian
H. armigera
has developed resistance to Cry1Ac toxin (275-fold). Some 70% of resistant
H. armigera
larvae were able to survive on Cry1Ac transgenic cotton (Ingard) The resistance phenotype is inherited as an autosomal semidominant trait. Resistance was associated with elevated esterase levels, which cosegregated with resistance. In vitro studies employing surface plasmon resonance technology and other biochemical techniques demonstrated that resistant strain esterase could bind to Cry1Ac protoxin and activated toxin. In vivo studies showed that Cry1Ac-resistant larvae fed Cy1Ac transgenic cotton or Cry1Ac-treated artificial diet had lower esterase activity than non-Cry1Ac-fed larvae. A resistance mechanism in which esterase sequesters Cry1Ac is proposed.
Quantitative Analysis of Group II Intron Expression and Splicing inLactococcus lactis
Authors: Chen Yuqing , Klein Joanna R. , McKay Larry L. , Dunny Gary M.
Published: May 2005

The group II intron Ll.ltrB is found within theltrBrelaxase gene of the conjugative element pRS01 inLactococcus lactis. Precise splicing of the intron is essential for pRS01 transfer. The transcription regulation and in vivo splicing activity of Ll.ltrB have not been investigated thoroughly inL. lactisin the natural pRS01 context. We developed absolute quantitative real-time reverse transcription-PCR assays to quantify RNA levels of the 5′ exon (ltrBE1) and the spliced relaxase (ltrB) and intron-encoded protein (ltrA) genes, as well as Ll.ltrB splicing activity under different physiological conditions. The mRNA levels for the ATP-binding protein OppD were assayed for comparison to theltrBtranscripts. TheoppDmRNA ranged from 10- to 10,000-fold higher thanltrBregion genes.ltrBE1expression was growth-phase dependent. The mRNA level ofltrAwas almost constant during all growth phases and in all media tested. Ll.ltrB in vivo splicing activity ranged from (6.5 ± 2.1)% to (22.1 ± 8.0)%. Acid challenge significantly decreased bothltrBregion mRNA levels and intron splicing activity. The presence of recipient cells, different mating environments, and temperature stress had no significant effects on expression and splicing. Western blotting showed that the level of LtrB protein expressed from an intronlessltrBgene was much higher (about 20-fold) than the level of protein expressed from an intron-containing construct. Interestingly, LtrB protein showed a tendency to function incison itsoriTtarget. The low level ofltrBtranscript and relatively inefficient splicing of the intron may limit Ll.ltrB mobility and dissemination in nature.
Architecture of a Nascent
Sphingomonas
sp. Biofilm under Varied Hydrodynamic Conditions
Authors: Venugopalan V. P. , Kuehn M. , Hausner M. , Springael D. , Wilderer P. A. , Wuertz S.
Published: May 2005

The architecture of a
Sphingomonas
biofilm was studied during early phases of its formation, using strain L138, a
gfp
-tagged derivative of
Sphingomonas
sp. strain LB126, as a model organism and flow cells and confocal laser scanning microscopy as experimental tools. Spatial and temporal distribution of cells and exopolymer secretions (EPS) within the biofilm, development of microcolonies under flow conditions representing varied Reynolds numbers, and changes in diffusion length with reference to EPS production were studied by sequential sacrificing of biofilms grown in multichannel flow cells and by time-lapse confocal imaging. The area of biofilm in terms of microscopic images required to ensure representative sampling varied by an order of magnitude when area of cell coverage (2 × 10
5
μm
2
) or microcolony size (1 × 10
6
μm
2
) was the biofilm parameter under investigation. Hence, it is necessary to establish the inherent variability of any biofilm metric one is attempting to quantify.
Sphingomonas
sp. strain L138 biofilm architecture consisted of microcolonies and extensive water channels. Biomass and EPS distribution were maximal at 8 to 9 μm above the substratum, with a high void fraction near the substratum. Time-lapse confocal imaging and digital image analysis showed that growth of the microcolonies was not uniform: adjacently located colonies registered significant growth or no growth at all. Microcolonies in the biofilm had the ability to move across the attachment surface as a unit, irrespective of fluid flow direction, indicating that movement of microcolonies is an inherent property of the biofilm. Width of water channels decreased as EPS production increased, resulting in increased diffusion distances in the biofilm. Changing hydrodynamic conditions (Reynolds numbers of 0.07, 52, and 87) had no discernible influence on the characteristics of microcolonies (size, shape, or orientation with respect to flow) during the first 24 h of biofilm development. Inherent factors appear to have overriding influence, vis-à-vis environmental factors, on early stages of microcolony development under these laminar flow conditions.
Distribution and Stability of Sulfate-Reducing Prokaryotic and Hydrogenotrophic Methanogenic Assemblages in Nutrient-Impacted Regions of the Florida Everglades
Authors: Castro Hector , Newman Susan , Reddy K. R. , Ogram Andrew
Published: May 2005

Although the influence of phosphorus loading on the Everglades ecosystem has received a great deal of attention, most research has targeted macro indicators, such as those based on vegetation or fauna, or chemical and physical parameters involved in biogeochemical cycles. Fewer studies have addressed the role of microorganisms, and these have mainly targeted gross informative parameters such as microbial biomass, enzymatic activities, and microbial enumerations. The objectives of this study were to characterize the dynamics of sulfate-reducing and methanogenic assemblages using terminal restriction fragment length polymorphism (T-RFLP) targeting the dissimilatory sulfite reductase (
dsrA
) and methyl coenzyme M reductase (
mcrA
) genes, respectively, and assess the impact of nutrient enrichment on microbial assemblages in the northern Everglades. T-RFLP combined with principal component analysis was a powerful technique to discriminate between soils from sites with eutrophic, transitional, and oligotrophic nutrient concentrations.
dsrA
T-RFLP provided a higher level of discrimination between the three sites.
mcrA
was a relatively weaker system to distinguish between sites, since it could not categorically discriminate between eutrophic and transition soil samples, but may be useful as an early indicator of phosphorus loading which is altering hydrogenotrophic methanogenic community in the transition zones, making them more similar to eutrophic zones. Clearly, targeting a combination of different microbial communities provides greater insight into the functioning of this ecosystem and provides useful information for understanding the relationship between eutrophication effects and microbial assemblages.
Combined Approach for Characterization of Uncultivated Magnetotactic Bacteria from Various Aquatic Environments
Authors: Flies Christine B. , Peplies Jörg , Schüler Dirk
Published: May 2005

Both magnetic collection and “race track” purification techniques were highly effective for selective enrichment of magnetotactic bacteria (MTB) from complex communities, as suggested by amplified ribosomal DNA restriction analysis and denaturing gradient gel electrophoresis combined with sequence analysis of 16S rRNA genes. Using these purification methods, the occurrence and diversity of MTB in microcosms from various marine and freshwater environments were assayed by using a combined microscopic, molecular, and cultivation approach. Most microcosms were dominated by magnetotactic cocci. Consistently, the majority of retrieved 16S RNA sequences were affiliated with a distinct cluster in the
Alphaproteobacteria
. Within this lineage the levels of sequence divergence were <1 to 11%, indicating genus-level diversity between magnetotactic cocci from various microcosms, as well as between MTB from different stages of succession of the same microcosms. The community composition in microscosms underwent drastic succession during incubation, and significant heterogeneities were observed between microcosms from the same environmental sources. A novel magnetotactic rod (MHB-1) was detected in a sediment sample from a lake in northern Germany by fluorescence in situ hybridization. MHB-1 falls into the
Nitrospira
phylum, displaying 91% 16S rRNA sequence similarity to “
Magnetobacterium bavaricum
.” In extensive cultivation attempts, we failed to isolate MHB-1, as well as most other MTB present in our samples. However, although magnetotactic spirilla were not frequently observed in the enrichments, 10 novel isolates of the genus
Magnetospirillum
which had not routinely been isolated in pure culture before were obtained.
Sensitivity of Planktonic and Biofilm-Associated
Salmonella
spp. to Ionizing Radiation
Authors: Niemira Brendan A. , Solomon Ethan B.
Published: May 2005

Salmonella enterica
forms biofilms that are relatively resistant to chemical sanitizing treatments. Ionizing radiation has been used to inactivate
Salmonella
on a variety of foods and contact surfaces, but the relative efficacy of the process against biofilm-associated cells versus free-living planktonic cells is not well documented. The radiation sensitivity of planktonic or biofilm-associated cells was determined for three food-borne-illness-associated isolates of
Salmonella
. Biofilms were formed on sterile glass slides in a coincubation apparatus, using inoculated tryptic soy broth, incubated at 37°C for 48 h. Resulting biofilms were 18 to 24 μm in height as determined by confocal scanning laser microscopy. The planktonic and biofilm cultures were gamma irradiated to doses of 0.0 (control), 0.5, 1.0, 1.5, 2.0 and 2.5 kGy. The
D
10
value (the dose of radiation required to reduce a population by 1 log
10
, or 90%) was calculated for each isolate-culture based on surviving populations at each radiation dose. The
D
10
values of
S. enterica
serovar Anatum were not significantly (
P
< 0.05) different for biofilm-associated (0.645 kGy) and planktonic (0.677 kGy) cells. In contrast, the biofilm-associated cells of
S. enterica
serovar Stanley were significantly more sensitive to ionizing radiation than the respective planktonic cells, with
D
10
values of 0.531 and 0.591 kGy, respectively.
D
10
values of
S. enterica
serovar Enteritidis were similarly reduced for biofilm-associated (0.436 kGy) versus planktonic (0.535 kGy) cells. The antimicrobial efficacy of ionizing radiation is therefore preserved or enhanced in treatment of biofilm-associated bacteria.
Investigation of the Microbial Ecology of Intertidal Hot Springs by Using Diversity Analysis of 16S rRNA and Chitinase Genes
Authors: Hobel Cédric F. V. , Marteinsson Viggó T. , Hreggvidsson Gudmundur Ó. , Kristjánsson Jakob K.
Published: May 2005

The microbial diversity of intertidal hot springs on the seashore of northwest Iceland was examined by combining directed in situ enrichments, artificial support colonization, and mat sampling. Analysis of 16S rRNA genes revealed the presence of clones related to both marine and terrestrial, thermophilic, mesophilic, and psychrophilic microorganisms scattered among 11 bacterial divisions. No archaea were found. The species composition of the enrichments was affected by the length of the hot periods experienced at low tide and was very different from those found in the biomass. A total of 36 chitinase genes were detected by molecular screening of the samples with degenerate primers for glycoside hydrolase family 18. The chitinase gene diversity was at least twofold higher in the enrichment samples than in the controls, indicating that a much higher diversity of hydrolytic genes can be accessed with this approach.
Lactococcus lactis
SpOx Spontaneous Mutants: a Family of Oxidative-Stress-Resistant Dairy Strains
Authors: Rochat Tatiana , Gratadoux Jean-Jacques , Corthier Gérard , Coqueran Bérard , Nader-Macias Maria-Elena , Gruss Alexandra , Langella Philippe
Published: May 2005

Numerous industrial bacteria generate hydrogen peroxide (H
2
O
2
), which may inhibit the growth of other bacteria in mixed ecosystems. We isolated
sp
ontaneous
ox
idative-stress-resistant (SpOx)
Lactococcus lactis
mutants by using a natural selection method with milk-adapted strains on dairy culture medium containing H
2
O
2
. Three SpOx mutants displayed greater H
2
O
2
resistance. One of them, SpOx3, demonstrated better behavior in different oxidative-stress situations: (i) higher long-term survival upon aeration in LM17 and milk and (ii) the ability to grow with H
2
O
2
-producing
Lactobacillus delbrueckii
subsp.
delbrueckii
strains. Furthermore, the transit kinetics of the SpOx3 mutant in the digestive tract of a human flora-associated mouse model was not affected.
Genetically Engineered Wine Yeast Produces a High Concentration of
l
-Lactic Acid of Extremely High Optical Purity
Authors: Saitoh Satoshi , Ishida Nobuhiro , Onishi Toru , Tokuhiro Kenro , Nagamori Eiji , Kitamoto Katsuhiko , Takahashi Haruo
Published: May 2005

For mass production of lactic acid, we newly constructed a transgenic wine yeast strain that included six copies of the bovine
l
-lactate dehydrogenase gene on the genome. On fermentation in inexpensive cane juice-based medium,
l
-lactate production of this recombinant reached 122 g/liter and the optical purity was 99.9% or higher.
Mass Outbreak of Food Poisoning Disease Caused by Small Amounts of Staphylococcal Enterotoxins A and H
Authors: Ikeda Tetsuya , Tamate Naoto , Yamaguchi Keiji , Makino Sou-ichi
Published: May 2005

It was believed that food poisoning in Osaka in 2000 was due to small amounts of staphylococcal enterotoxin A (SEA) in reconstituted milk. Results of this study clearly indicate that SEH was also present in the raw material of reconstituted milk, indicating that the food poisoning was caused by multiple staphylococcal enterotoxins.
Combined Antimicrobial Resistance in
Enterococcus faecium
Isolated from Chickens
Authors: Petsaris Odile , Miszczak Fabien , Gicquel-Bruneau Mireille , Perrin-Guyomard Agnès , Humbert Florence , Sanders Pascal , Leclercq Roland
Published: May 2005

Nineteen
E. faecium
strains isolated from chicken caecum samples, collected in slaughterhouses and highly resistant to vancomycin or gentamicin, were coresistant to erythromycin, and/or tetracyclines, and/or streptogramins, and/or avilamycin. Multiple antibiotic resistance was related to the presence in various combinations of
aac(6′)-aph(2")
,
erm
(B),
emtA
,
mef
(A),
tet
(L),
tet
(M), and
vanA
genes.
UV Inactivation of
Cryptosporidium hominis
as Measured in Cell Culture
Authors: Johnson Anne M. , Linden Karl , Ciociola Kristina M. , De Leon Ricardo , Widmer Giovanni , Rochelle Paul A.
Published: May 2005

The
Cryptosporidium
spp. UV disinfection studies conducted to date have used
Cryptosporidium parvum
oocysts. However,
Cryptosporidium hominis
predominates in human cryptosporidiosis infections, so there is a critical need to assess the efficacy of UV disinfection of
C. hominis
. This study utilized cell culture-based methods to demonstrate that
C. hominis
oocysts displayed similar levels of infectivity and had the same sensitivity to UV light as
C. parvum
. Therefore, the water industry can be confident about extrapolating
C. parvum
UV disinfection data to
C. hominis
oocysts.
THE CONTINUUM SHELL MODEL WITH FULL CORRECTION FOR TARGET RECOIL
Authors: HALDERSON DEAN
Published: May 2005

A brief history of the continuum shell model with full correction for target recoil is provided. Past applications to nucleon induced reactions, nucleon capture, knockout reactions by pions and electrons, and strangeness exchange reactions are provided. Recent progress of the model is reviewed. Examples of continuum states for p-shell nuclei, derived from both two and three-body interactions, are given. Finally, the general model is presented in which any core states and any states of the composite system may be incorporated in a calculation.
PLASMA FLOW CHARACTERISTICS INSIDE THE SUPERSONIC D.C. PLASMA TORCH
Authors: YUAN X. Q. , ZHAO T. Z. , GUO W. K. , XU P.
Published: May 2005

A magnetohydrodynamic (MHD) model, which describes supersonic plasma flow inside the torch, is presented in this paper. It is a two-dimensional model but includes the K -epsilon model of turbulence, the gas viscous effects and compressible effects. The PHOENICS software is used for solving the governing equations, i.e. the conservation equations of mass, momentum, and energy together with the equations describing the K -epsilon model of turbulence. The calculated arc voltages and gas inflow rates are consistent with the experimental results when arc current and the working gas are the same as experiment. The plasma flow characteristics inside the supersonic plasma torch are analyzed in detail. Temperature, velocity, pressure and Mach number contours are presented to show the flow characteristics. Comparisons between turbulent and laminar models are made in detail also, and the results show the turbulent enhanced momentum and energy transport inside the supersonic plasma torch has little effect on the whole discharge area. The plasma flow inside the supersonic torch is mainly in the laminar state.
THE GENETICS OF PSORIASIS AND AUTOIMMUNITY
Authors: Bowcock Anne M.
Published: May 2005

▪ Abstract  Psoriasis is an inflammatory/autoimmune disease and, as with many autoimmune diseases, is associated with alleles from the major histocompatibility complex (MHC). With psoriasis and autoimmune disease, the penetrance of the MHC-associated alleles is never 100%, even for monozygotic twins. This may be because development requires additional environmental and/or genetic modifiers or requires specific T-cell receptor arrangements. Families segregating single or multilocus susceptibility alleles other than the MHC have also been reported. Overlapping genetic locations of loci for different autoimmune diseases have been known for several years and are starting to reveal common genes or genetic variants. These include genes normally involved in preventing spontaneous T-cell activation or proliferation, immune synapse formation, or cytokine production via pathways such as those mediated by NFκB and those involved in thymic selection. Autoimmunity may also involve dysregulation of genes or pathways regulated by the RUNX family of transcription factors. RUNX is involved in hematopoietic cell development, development of T cells in the thymus, chromatin remodeling, and gene silencing. Hence, its effect on cells of the immune system may be due to variable changes in gene expression and could account for variable body surface involvement and waxing and waning of disease.
ALTERNATIVECANDIDA ALBICANSLIFESTYLES: Growth on Surfaces
Authors: Kumamoto Carol A. , Vinces Marcelo D.
Published: May 2005

Candida albicans, an opportunistic fungal pathogen, causes a wide variety of human diseases such as oral thrush and disseminated candidiasis. Many aspects of C. albicans physiology have been studied during liquid growth, but in its natural environment, the gastrointestinal tract of a mammalian host, the organism associates with surfaces. Growth on a surface triggers several behaviors, such as biofilm formation, invasion, and thigmotropism, that are important for infection. Recent discoveries have identified factors that regulate these behaviors and revealed the importance of these behaviors for pathogenesis.
HUMAN MILK GLYCANS PROTECT INFANTS AGAINST ENTERIC PATHOGENS
Authors: Newburg David S. , Ruiz-Palacios Guillermo M. , Morrow Ardythe L.
Published: May 2005

▪ Abstract  Breastfed infants have lower morbidity and mortality due to diarrhea than those fed artificially. This had been attributed primarily to the secretory antibodies and prebiotic factors in human milk. Oligosaccharides are the third largest component of human milk. They were initially considered to be functionless by-products of glycoprotein and glycolipid synthesis during milk production. However, in the past few decades it has become apparent that the human milk oligosaccharides are composed of thousands of components, at least some of which protect against pathogens. Oligosaccharide protection against infectious agents may result in part from their prebiotic characteristics, but is thought to be primarily due to their inhibition of pathogen binding to host cell ligands. Most human milk oligosaccharides are fucosylated, and their production depends on enzymes encoded by the genes associated with expression of the Lewis blood group system. The expression of specific fucosylated oligosaccharides in milk thus varies in relation to maternal Lewis blood group type, and is significantly associated with the risk of infectious disease in breastfed infants. Specific fucosylated moieties of oligosaccharides and related glycoconjugates (glycans) are able to inhibit binding and disease by specific pathogens. This review presents the argument that specific glycans, especially the oligosaccharides, are the major constituent of an innate immune system of human milk whereby the mother protects her infant from enteric and other pathogens through breastfeeding. The large input of energy expended by the mother in the synthesis of milk oligosaccharides is consistent with the human reproductive strategy of large parental input into rearing relatively few offspring through a prolonged period of maturation. These protective glycans may prove useful as a basis for the development of novel prophylactic and therapeutic agents that inhibit diseases caused by mucosal pathogens.
Weighted norm inequalities for a class of rough singular integrals
Authors: Al-Qassem H. M.
Published: May 2005

Weighted norm inequalities are proved for a rough homogeneous
singular integral operator and its corresponding maximal truncated singular operator. Our results are essential improvements as well as extensions of some known results on the
weighted boundedness of singular integrals.
On injective L‐modules
Authors: Isaac Paul
Published: May 2005

The concepts of free modules, projective modules, injective modules,
and the like form an important area in module theory. The notion of free fuzzy modules was introduced by Muganda as an extension of free modules in the fuzzy context. Zahedi and Ameri introduced the concept of projective and injective L‐modules. In this paper, we give an alternate definition for injective L‐modules and prove that a direct sum of L‐modules is injective if and only if each L‐module in the sum is injective. Also we prove that if J is an injective module and μ is an injective L‐submodule of J, and if is a short exact sequence of L‐modules, then ν≃μ ⊕ η.
Computation of antieigenvalues
Authors: Seddighin Morteza
Published: May 2005

We will use a theorem by M. G. Kreĭn and properties of the numerical range of an operator to develop a method of computation for the
first antieigenvalue of a strictly accretive operator.
Elevated Blood Pressure Linked to Primary Hyperaldosteronism and Impaired Vasodilation in BK Channel–Deficient Mice
Authors: Sausbier Matthias , Arntz Claudia , Bucurenciu Iancu , Zhao Hong , Zhou Xiao-Bo , Sausbier Ulrike , Feil Susanne , Kamm Simone , Essin Kyrill , Sailer Claudia A. , Abdullah Usamah , Krippeit-Drews Peter , Feil Robert , Hofmann Franz , Knaus Hans-Günther , Kenyon Chris , Shipston Michael J. , Storm Johan F. , Neuhuber Winfried , Korth Michael , Schubert Rudolf , Gollasch Maik , Ruth Peter
Published: May 2005

Background—

Abnormally elevated blood pressure is the most prevalent risk factor for cardiovascular disease. The large-conductance, voltage- and Ca
2+
-dependent K
+
(BK) channel has been proposed as an important effector in the control of vascular tone by linking membrane depolarization and local increases in cytosolic Ca
2+
to hyperpolarizing K
+
outward currents. However, the BK channel may also affect blood pressure by regulating salt and fluid homeostasis, particularly by adjusting the renin-angiotensin-aldosterone system.

Methods and Results—

Here we report that deletion of the pore-forming BK channel α subunit leads to a significant blood pressure elevation resulting from hyperaldosteronism accompanied by decreased serum K
+
levels as well as increased vascular tone in small arteries. In smooth muscle from small arteries, deletion of the BK channel leads to a depolarized membrane potential, a complete lack of membrane hyperpolarizing spontaneous K
+
outward currents, and an attenuated cGMP vasorelaxation associated with a reduced suppression of Ca
2+
transients by cGMP. The high level of BK channel expression observed in wild-type adrenal glomerulosa cells, together with unaltered serum renin activities and corticotropin levels in mutant mice, suggests that the hyperaldosteronism results from abnormal adrenal cortical function in BK
−/−
mice.

Conclusions—

These results identify previously unknown roles of BK channels in blood pressure regulation and raise the possibility that BK channel dysfunction may underlie specific forms of hyperaldosteronism.
Female Mice Lacking Estrogen Receptor β Display Prolonged Ventricular Repolarization and Reduced Ventricular Automaticity After Myocardial Infarction
Authors: Korte Thomas , Fuchs Martin , Arkudas Andreas , Geertz Sebastian , Meyer Rainer , Gardiwal Ajmal , Klein Gunnar , Niehaus Michael , Krust Andrée , Chambon Pierre , Drexler Helmut , Fink Klaus , Grohé Christian
Published: May 2005

Background—

Major gender-based differences in the incidence of ventricular tachyarrhythmia after myocardial infarction have been shown in humans. Although the underlying mechanisms are unclear, earlier studies suggest that estrogen receptor–mediated effects play a major role in this process.

Methods and Results—

We examined the effect of estrogen receptor α (ERα) and estrogen receptor β (ERβ) on the electrophysiological phenotype in female mice with and without chronic anterior myocardial infarction. There was no significant difference in overall mortality, infarct size, and parameters of left ventricular remodeling when we compared infarcted ERα-deficient and ERβ-deficient mice with infarcted wild-type animals. In the 12-hour telemetric ECG recording 6 weeks after myocardial infarction, surface ECG parameters did not show significant differences in comparisons of ERα-deficient mice versus wild-type controls, infarcted versus noninfarcted ERα-deficient mice, and infarcted ERα-deficient versus infarcted wild-type mice. However, infarcted ERβ-deficient versus noninfarcted ERβ-deficient mice showed a significant prolongation of the QT (61±6 versus 48±8 ms;
P
<0.05) and QTc intervals (61±7 versus 51±9 ms;
P
<0.05) and the JT (42±6 versus 31±4 ms;
P
<0.05) and JTc intervals (42±7 versus 33±4 ms;
P
<0.05). Furthermore, infarcted ERβ-deficient versus infarcted wild-type mice showed a significant prolongation of the QT (61±6 versus 53±8 ms;
P
<0.05) and QTc intervals (61±7 versus 53±7 ms;
P
<0.05) and the JT (42±6 versus 31±5 ms;
P
<0.05) and JTc intervals (42±7 versus 31±5 ms;
P
<0.05), accompanied by a significant decrease of ventricular premature beats (7±21/h versus 71±110/h;
P
<0.05). Finally, real-time polymerase chain reaction–based quantitative analysis of mRNA levels showed a significantly lower expression of Kv4.3 (coding for
I
to
) in ERβ-deficient mice (
P
<0.05).

Conclusions—

Estrogen receptor β deficiency results in prolonged ventricular repolarization and decreased ventricular automaticity in female mice with chronic myocardial infarction.
Peak Oxygen Consumption as a Predictor of Death in Patients With Heart Failure Receiving β-Blockers
Authors: O’Neill James O. , Young James B. , Pothier Claire E. , Lauer Michael S.
Published: May 2005

Background—

Peak oxygen uptake (peak V̇
o
2
) is a strong predictor of mortality and is commonly used in the evaluation of patients for cardiac transplantation. β-Blockers reduce mortality in patients with heart failure, without influencing peak V̇
o
2
, raising the possibility that peak V̇
o
2
is no longer suitable as an indicator of prognosis in these patients.

Methods and Results—

We analyzed prospectively gathered data on 2105 patients referred for cardiopulmonary testing for all-cause mortality and for occurrence of death or transplantation. Patients receiving β-blockers were younger, more likely to have coronary disease, and had a greater mean ejection fraction but had a similar peak V̇
o
2
. There were 555 deaths (26%) and 194 (9%) transplants during a median follow-up of 3.5 years. Peak V̇
o
2
was a predictor of mortality irrespective of β-blocker use; a decrease of 1 mL · kg
−1
· min
−1
resulted in an adjusted hazard ratio (HR) of 1.13 (95% CI 1.09 to 1.17,
P
<0.0001) in patients not receiving β-blockers and 1.27 (95% CI 1.18 to 1.36,
P
<0.0001) in patients receiving β-blockers. Similar findings were noted when considering death or transplantation as an end point. β-Blocker use was associated with better outcomes until peak V̇
o
2
values became very low (≈10 mL · kg
−1
· min
−1
), at which level survival rates were equally poor.

Conclusion—

Peak V̇
o
2
is a determinant of survival in patients in heart failure even in the setting of β-blockade. Because of improved survival in patients treated with β-blockers, the cut point value of 14 mg · kg
−1
· min
−1
for referral for cardiac transplantation in these patients requires reevaluation, and a lower cut point may be more appropriate.
Early Onset and Progression of Left Ventricular Remodeling After Alcohol Septal Ablation in Hypertrophic Obstructive Cardiomyopathy
Authors: van Dockum Willem G. , Beek Aernout M. , ten Cate Folkert J. , ten Berg Jurrien M. , Bondarenko Olga , Götte Marco J.W. , Twisk Jos W.R. , Hofman Mark B.M. , Visser Cees A. , van Rossum Albert C.
Published: May 2005

Background—

Alcohol septal ablation (ASA) reduces left ventricular outflow tract (LVOT) pressure gradient in patients with hypertrophic obstructive cardiomyopathy (HOCM), which leads to left ventricular remodeling. We sought to describe the early to midterm changes and modulating factors of the remodeling process using cardiac MRI (CMR).

Methods and Results—

CMR was performed at baseline and 1 and 6 months after ASA in 29 patients with HOCM (age 52±16 years). Contrast-enhanced CMR showed no infarct-related hyperenhancement outside the target septal area. Septal mass decreased from 75±23 g at baseline to 68±22 and 58±19 g (
P
<0.001) at 1- and 6-month follow-up, respectively. Remote, nonseptal mass decreased from 141±41 to 132±40 and 111±27 g (
P
<0.001), respectively. Analysis of temporal trends revealed that septal mass reduction was positively associated with contrast-enhanced infarct size and transmural or left-sided septal infarct location at both 1 and 6 months. Remote mass reduction was associated with infarct location at 6 months but not with contrast-enhanced infarct size. By linear regression analysis, percentage remote mass reduction correlated significantly with LVOT gradient reduction at 6-month follow-up (
P
=0.03).

Conclusions—

Left ventricular remodeling after ASA occurs early and progresses on midterm follow-up, modulated by CMR infarct size and location. Remote mass reduction is associated with infarct location and correlates with reduction of the LVOT pressure gradient. Thus, myocardial hypertrophy in HOCM is, at least in part, afterload dependent and reversible and is not exclusively caused by the genetic disorder.
p38 MAP Kinase Mediates Inflammatory Cytokine Induction in Cardiomyocytes and Extracellular Matrix Remodeling in Heart
Authors: Li Manxiang , Georgakopoulos Dimitrios , Lu Gang , Hester Lisa , Kass David A. , Hasday Jeffery , Wang Yibin
Published: May 2005

Background—

Increasing evidence suggests that development of heart failure involves activation of stress-response inflammatory cytokines, including tumor necrosis factor-α and interleukin-6. Yet, the myocyte contribution to their induction in failing hearts and the underlying regulatory mechanism in stressed myocardium remain unclear.

Methods and Results—

In cultured cardiac myocytes, specific activation of stress-activated mitogen-activated protein kinase, p38, by upstream activator MKK6bE led to significant induction of tumor necrosis factor-α and interleukin-6 secretion, whereas treating cells with a selective p38 inhibitor (SB239068) significantly blocked the cytokine secretion from myocytes and increased their intracellular accumulation. Targeted expression of MKK6bE in transgenic hearts also resulted in a marked elevation in plasma tumor necrosis factor-α and interleukin-6; oral administration of SB239068 resulted in a significant reduction in their plasma levels but an increase in intracardiac accumulation of both cytokines. MKK6bE transgenic hearts developed marked interstitial fibrosis with increased matrix metalloproteinase abundance and selective induction of tissue inhibitor of matrix metalloproteinase-1; this extracellular matrix remodeling was also significantly attenuated by p38 inhibition. Along with cytokine induction and extracellular remodeling, MKK6bE transgenic animals displayed impaired hemodynamic function, whereas p38 inhibition improved the cardiac performance and prolonged the survival of the animals.

Conclusions—

Stress-activated p38 kinase is a critical regulator of inflammatory response in cardiomyocytes with significant contribution to pathological remodeling in stressed myocardium. Inhibition of p38 may represent a useful therapeutic avenue to ameliorate cardiac pathology and heart failure evolution.
Aortic Input Impedance Increases With Age in Healthy Men and Women
Authors: Mazzaro Luciano , Almasi Stephen J. , Shandas Robin , Seals Douglas R. , Gates Phillip E.
Published: May 2005

Aortic input impedance represents the hydraulic load presented by the systemic circulation to the left ventricle of the heart and is increased in patients with cardiovascular disease. Aging is a strong independent risk factor for cardiovascular disease and could exert this effect partly through an increase in modulus of aortic input impedance. We used a novel noninvasive technique to determine aortic input impedance in 71 healthy men and women aged 20 to 69 years. We found that the aortic input impedance spectrum was shifted rightward with advancing age, characterized by a 37% increase in the frequency of the minimum modulus between the third and seventh decade (
P
<0.0001). The frequency of the minimum modulus correlated with age in all subjects (
r
=0.48;
P
<0.0001), in men (
r
=0.43;
P
<0.005), and in women (
r
=0.53;
P
=0.001). Although several physical characteristics were associated with the frequency of the minimum modulus (bivariate correlation), a regression model that included age and these physical characteristics showed that age was the only independent predictor of the frequency of the minimum modulus. We conclude that aortic input impedance increases with advancing age in healthy men and women. This increase in aortic input impedance may be an important mechanism by which age increases the risk of cardiovascular disease in humans.
Renin-Angiotensin System Modulates Oxidative Stress–Induced Endothelial Cell Apoptosis in Rats
Authors: Akishita Masahiro , Nagai Kumiko , Xi Hang , Yu Wei , Sudoh Noriko , Watanabe Tokumitsu , Ohara-Imaizumi Mica , Nagamatsu Shinya , Kozaki Koichi , Horiuchi Masatsugu , Toba Kenji
Published: May 2005

The role of the renin-angiotensin system in oxidative stress–induced apoptosis of endothelial cells (ECs) was investigated using a rat model and cultured ECs. EC apoptosis was induced by 5-minute intra-arterial treatment of a rat carotid artery with 0.01 mmol/L H
2
O
2
and was evaluated at 24 hours by chromatin staining of
en face
specimens with Hoechst 33342. Although activity of angiotensin-converting enzyme in arterial homogenates was not increased, administration of an angiotensin-converting enzyme inhibitor temocapril for 3 days before H
2
O
2
treatment inhibited EC apoptosis, followed by reduced neointimal formation 2 weeks later. Also, an angiotensin II type 1 (AT1) receptor blocker (olmesartan) inhibited EC apoptosis, whereas angiotensin II administration accelerated apoptosis independently of blood pressure. Next, cultured ECs derived from a bovine carotid artery were treated with H
2
O
2
to induce apoptosis, as evaluated by DNA fragmentation. Combination of angiotensin II and H
2
O
2
dose-dependently increased EC apoptosis and 8-isoprostane formation, a marker of oxidative stress. Conversely, temocapril and olmesartan reduced apoptosis and 8-isoprostane formation induced by H
2
O
2
, suggesting that endogenous angiotensin II interacts with H
2
O
2
to elevate oxidative stress levels and EC apoptosis. Neither an AT2 receptor blocker, PD123319, affected H
2
O
2
-induced apoptosis, nor a NO synthase inhibitor,
N
G
-nitro-
l
-arginine methyl ester, influenced the effect of temocapril on apoptosis in cell culture experiments. These results suggest that AT1 receptor signaling augments EC apoptosis in the process of oxidative stress–induced vascular injury.
Metabolic Syndrome Is Associated With Aortic Stiffness in Untreated Essential Hypertension
Authors: Schillaci Giuseppe , Pirro Matteo , Vaudo Gaetano , Mannarino Massimo R. , Savarese Gianluca , Pucci Giacomo , Franklin Stanley S. , Mannarino Elmo
Published: May 2005

Metabolic syndrome is a powerful predictor of cardiovascular disease in hypertension, and large-artery stiffness is increasingly recognized as a cardiovascular risk factor. We hypothesized that the adverse prognostic significance of the metabolic syndrome in hypertension might be explained in part by its association with aortic stiffness. A total of 169 newly diagnosed, never treated, nondiabetic patients with essential hypertension (men 55%, 48±11 years) were classified by the presence (n=45) or absence (n=124) of the metabolic syndrome. All patients underwent aortic and upper limb pulse wave velocity determination by means of an applanation tonometry-based method. Aortic pulse wave velocity had a direct correlation with office and 24-hour systolic pressure (
r
=0.42 and 0.31, respectively), as well as with waist circumference (
r
=0.35, all
P
<0.001), but not with body mass index (
r
=0.10,
P
=not significant). Aortic pulse wave velocity was higher in the subgroup with the metabolic syndrome (10.0±2.7 versus 8.8±2.1 m/s;
P
=0.003), whereas upper limb velocity did not differ in the 2 groups (8.6±1.4 versus 8.7±1.5 m/s;
P
=not significant). In a multiple regression, aortic pulse wave velocity was independently associated with age, systolic blood pressure, and the metabolic syndrome. Only diastolic BP independently predicted upper limb pulse wave velocity. We conclude that in untreated hypertension, the metabolic syndrome is independently associated with a higher aortic, but not upper limb, pulse wave velocity. Central, but not general, adiposity is an important determinant of aortic stiffness in hypertension.
Calcium-Activated Potassium Channels and NO Regulate Human Peripheral Conduit Artery Mechanics
Authors: Bellien Jeremy , Joannides Robinson , Iacob Michele , Arnaud Philippe , Thuillez Christian
Published: May 2005

The role of NO in the regulation of the mechanical properties of conduit arteries is controversial in humans, and the involvement of an endothelium-derived hyperpolarizing factor (EDHF), acting through calcium-activated potassium (K
Ca
) channels, has never been investigated at this level in vivo. We assessed in healthy volunteers, after oral administration of aspirin (500 mg), the effect of local infusion of
N
G
-monomethyl-
l
-arginine (
l
-NMMA; 8 μmol/min for 8 minutes), an NO synthase inhibitor, tetraethylammonium chloride (TEA; 9 μmol/min for 8 minutes), a K
Ca
channels inhibitor, and the combination of both on radial artery internal diameter, wall thickness (echo tracking), blood flow (Doppler), and pressure. The incremental elastic modulus and compliance were fitted as functions of midwall stress.
l
-NMMA decreased modulus and increased compliance at high levels of midwall stress (all
P
<0.05) without affecting radial diameter. TEA reduced radial diameter from 2.68±0.07 to 2.50±0.08 10
−3
m, increased the modulus, and decreased the compliance at all levels of stress (all
P
<0.05). Combination of both inhibitors synergistically enhanced the increase in modulus, the decrease in diameter (from 2.71±0.10 to 2.42±0.09 10
−3
m), and compliance compared with TEA alone (all
P
<0.05). These results confirm that inhibition of NO synthesis is associated with a paradoxical isometric smooth muscle relaxation of the radial artery. They demonstrate the involvement of K
Ca
channels in the regulation of the mechanical properties of peripheral conduit arteries, supporting a role for EDHF at this level in vivo. Moreover, the synergistic effect of
l
-NMMA and TEA shows that K
Ca
channels compensate for the loss of NO synthesis to maintain peripheral conduit artery diameter and mechanics.
Ethical Issues Faced By Nursing Editors
Authors: Freda Margaret Comerford , Kearney Margaret H.
Published: May 2005

This study reports on ethical issues faced by editors of nursing journals, a topic which has not appeared in the nursing literature. A survey of nursing editors (n = 88)was conducted via e-mail; this article is the content analysis of survey questions about ethics. Eight categories of ethical issues emerged: problems with society/association/publisher; decisions about inflammatory submissions; informed consent or IRB issues; conflicts of interest; advertising pressures; duplicate publications and/or plagiarism; difficult interactions with authors; and authorship. Some issues were similar to those published about medical editors; however, others were unique. This study can assist authors to better understand some of the ethical issues in publishing, can help editors to view their issues in the context of what others experience, and can assist societies and publishers to work toward avoiding these ethical issues in the future. Professional discussions about ethics in nursing publications should be the subject of ongoing research and scientific inquiry.