bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification and Phenotypic Characterization of
Sphingomonas wittichii
Strain RW1 by Peptide Mass Fingerprinting Using Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry
Authors: Halden Rolf U. , Colquhoun David R. , Wisniewski Eric S.
Published: May 2005

Mass spectrometry is a potentially attractive means of monitoring the survival and efficacy of bioaugmentation agents, such as the dioxin-mineralizing bacterium
Sphingomonas wittichii
strain RW1. The biotransformation activity of RW1 phenotypes is determined primarily by the presence and concentration of the dioxin dioxygenase, an enzyme initiating the degradation of both dibenzo-
p
-dioxin and dibenzofuran (DF). We explored the possibility of identifying and characterizing putative cultures of RW1 by peptide mass fingerprinting (PMF) targeting this characteristic phenotypic biomarker. The proteome from cells of RW1—grown on various media in the presence and absence of DF—was partially purified, tryptically digested, and analyzed using matrix-assisted laser desorption ionization-time of flight mass spectrometry. Mascot online database queries allowed statistically significant identification of RW1 in disrupted, digested cells (
P
< 0.01 to 0.05) and in digested whole-cell extracts (
P
< 0.00001 to 0.05) containing hundreds of proteins, as determined by two-dimensional gel electrophoresis. Up to 14 peptide ions of the alpha subunit of the dioxin dioxygenase (43% protein coverage) were detected in individual samples. A minimum of 10
7
DF-grown cells was required to identify dioxin degradation-enabled phenotypes. The technique hinges on the detection of multiple characteristic peptides of a biomarker that can reveal at once the identity and phenotypic properties of the microbial host expressing the protein. The results demonstrate the power of PMF of minimally processed microbial cultures as a sensitive and specific technique for the positive identification and phenotypic characterization of certain microorganisms used in biotechnology and bioremediation.
Shifts in Rhizoplane Communities of Aquatic Plants after Cadmium Exposure
Authors: Stout Lisa M. , Nüsslein Klaus
Published: May 2005

In this study we present the comparative molecular analysis of bacterial communities of the aquatic plant
Lemna minor
from a contaminated site (RCP) and from a laboratory culture (EPA), as well as each of these with the addition of cadmium. Plants were identified as
L. minor
by analysis of the
rpl
16 chloroplast region. Comparative bacterial community studies were based on the analyses of 16S rRNA clone libraries, each containing about 100 clones from the root surfaces of plants. Bacterial communities were compared at three phylogenetic levels of resolution. At the level of bacterial divisions, differences in diversity index scores between treatments, with and without cadmium within the same plant type (EPA or RCP), were small, indicating that cadmium had little effect. When we compared genera within the most dominant group, the β-proteobacteria, differences between unamended and cadmium-amended libraries were much larger. Bacterial diversity increased upon cadmium addition for both EPA and RCP libraries. Analyses of diversity at the phylotype level showed parallel shifts to more even communities upon cadmium addition; that is, percentage changes in diversity indices due to cadmium addition were the same for either plant type, indicating that contamination history might be independent of disturbance-induced diversity shifts. At finer phylogenetic levels of resolution, the effects of cadmium addition on bacterial communities were very noticeable. This study is a first step in understanding the role of aquatic plant-associated microbial communities in phytoremediation of heavy metals.
DNA Microarray Analysis of Nitrogen Fixation and Fe(III) Reduction in
Geobacter sulfurreducens
Authors: Methé Barbara A. , Webster Jennifer , Nevin Kelly , Butler Jessica , Lovley Derek R.
Published: May 2005

A DNA microarray representing the genome of
Geobacter sulfurreducens
was constructed for use in global gene expression profiling of cells under steady-state conditions with acetate as the electron donor and Fe(III) or fumarate as the electron acceptor. Reproducible differences in transcript levels were also observed in comparisons between cells grown with ammonia and those fixing atmospheric nitrogen. There was a high correlation between changes in transcript levels determined with microarray analyses and an evaluation of a subset of the genome with quantitative PCR. As expected, cells required to fix nitrogen had higher levels of transcripts of genes associated with nitrogen fixation, further demonstrating that the microarray approach could reliably detect important physiological changes. Cells grown with Fe(III) as the electron acceptor had higher levels of transcripts for
omcB
, a gene coding for an outer membrane
c
-type cytochrome that is essential for Fe(III) reduction. Several other
c
-type cytochrome genes also appeared to be up-regulated. An unexpected result was significantly higher levels of transcripts for genes which have a role in metal efflux, potentially suggesting the importance of maintaining metal homeostasis during release of soluble metals when reducing Fe(III). A substantial proportion (30%) of significantly expressed genes during Fe(III) reduction were genes of unknown function or hypothetical proteins, suggesting differences in Fe(III) reduction physiology among microorganisms which perform this metabolic process.
Production of the Potent Antibacterial Polyketide Erythromycin C in
Escherichia coli
Authors: Peirú Salvador , Menzella Hugo G. , Rodríguez Eduardo , Carney John , Gramajo Hugo
Published: May 2005

An
Escherichia coli
strain capable of producing the potent antibiotic erythromycin C (Ery C) was developed by expressing 17 new heterologous genes in a 6-deoxyerythronolide B (6dEB) producer strain. The megalomicin gene cluster was used as the source for the construction of two artificial operons that contained the genes encoding the deoxysugar biosynthetic and tailoring enzymes necessary to convert 6dEB to Ery C. The reconstructed mycarose operon contained the seven genes coding for the enzymes that convert glucose-1-phosphate (G-1-P) to TDP-
l
-mycarose, a 6dEB mycarosyl transferase, and a 6dEB 6-hydroxylase. The activity of the pathway was confirmed by demonstrating conversion of exogenous 6dEB to 3-
O
-α-mycarosylerythronolide B (MEB). The reconstructed desosamine operon contained the six genes necessary to convert TDP-4-keto-6-deoxyglucose, an intermediate formed in the mycarose pathway, to TDP-
d
-desosamine, a desosamine transferase, a 6dEB 12-hydroxylase, and the rRNA methyltransferase ErmE; the last was required to confer resistance to the host cell upon production of mature macrolide antibiotics. The activity of this pathway was demonstrated by conversion of MEB to Ery C. When the mycarose and desosamine operons were expressed in an
E. coli
strain engineered to synthesize 6dEB, Ery C and Ery D were produced. The successful production of Ery C in
E. coli
shows the potentiality of this model microorganism to synthesize novel 6-deoxysugars and to produce bioactive glycosylated compounds and also establishes the basis for the future use of
E. coli
both in the production of new glycosylated polyketides and for the generation of novel bioactive compounds through combinatorial biosynthesis.
Clonal Expansion May Account for High Levels of Quinolone Resistance in
Salmonella enterica
Serovar Enteritidis
Authors: Kilmartin Donna , Morris D. , O'Hare C. , Corbett-Feeney G. , Cormican M.
Published: May 2005

We have observed a high incidence of isolated nalidixic acid resistance in
Salmonella enterica
serovar Enteritidis isolates in Ireland, particularly isolates of phage type 1 (PT1). A group of nalidixic acid-resistant (
n
= 22) and nalidixic acid-susceptible (
n
= 28) isolates of serovar Enteritidis from multiple sites in Ireland were selected. Isolates were typed by pulsed-field gel electrophoresis (PFGE) with XbaI, and the MICs for nalidixic acid and ciprofloxacin were determined. Mutations associated with nalidixic acid resistance in clinical isolates and laboratory mutants of serovar Enteritidis and 32 nalidixic acid-resistant isolates of 15 other salmonella serovars were identified. PFGE had limited discriminatory power. A specific point mutation (G246T) associated with amino acid substitution Asp87Tyr in the quinolone resistance determining region of the
gyrA
gene accounted for 95% of all mutations in serovar Enteritidis and for all mutations in PT1 isolates. Greater diversity of mutations was observed among all non-Enteritidis salmonella serovars studied. Rates of nalidixic acid resistance in serovar Enteritidis may predominantly reflect clonal expansion after infrequent mutation or selection events.
13
C Incorporation into Signature Fatty Acids as an Assay for Carbon Allocation in Arbuscular Mycorrhiza
Authors: Olsson Pål Axel , van Aarle Ingrid M. , Gavito Mayra E. , Bengtson Per , Bengtsson Göran
Published: May 2005

The ubiquitous arbuscular mycorrhizal fungi consume significant amounts of plant assimilated C, but this C flow has been difficult to quantify. The neutral lipid fatty acid 16:1ω5 is a quantitative signature for most arbuscular mycorrhizal fungi in roots and soil. We measured carbon transfer from four plant species to the arbuscular mycorrhizal fungus
Glomus intraradices
by estimating
13
C enrichment of 16:1ω5 and compared it with
13
C enrichment of total root and mycelial C. Carbon allocation to mycelia was detected within 1 day in monoxenic arbuscular mycorrhizal root cultures labeled with [
13
C]glucose. The
13
C enrichment of neutral lipid fatty acid 16:1ω5 extracted from roots increased from 0.14% 1 day after labeling to 2.2% 7 days after labeling. The colonized roots usually were more enriched for
13
C in the arbuscular mycorrhizal fungal neutral lipid fatty acid 16:1ω5 than for the root specific neutral lipid fatty acid 18:2ω6,9. We labeled plant assimilates by using
13
CO
2
in whole-plant experiments. The extraradical mycelium often was more enriched for
13
C than was the intraradical mycelium, suggesting rapid translocation of carbon to and more active growth by the extraradical mycelium. Since there was a good correlation between
13
C enrichment in neutral lipid fatty acid 16:1ω5 and total
13
C in extraradical mycelia in different systems (
r
2
= 0.94), we propose that the total amount of labeled C in intraradical and extraradical mycelium can be calculated from the
13
C enrichment of 16:1ω5. The method described enables evaluation of C flow from plants to arbuscular mycorrhizal fungi to be made without extraction, purification and identification of fungal mycelia.
Degradation of Azo Dyes by Laccase and Ultrasound Treatment
Authors: Tauber Michael M. , Guebitz Georg M. , Rehorek Astrid
Published: May 2005

The goal of this work was to investigate the decomposition of azo dyes by oxidative methods, such as laccase and ultrasound treatments. Each of these methods has strong and feeble sides. The laccase treatment showed high decolorization rates but cannot degrade all investigated dyes (reactive dyes), and high anionic strength led to enzyme deactivation. Ultrasound treatment can decolorize all tested dyes after 3 h at a high energy input, and prolonged sonication leads to nontoxic ionic species, which was demonstrated by ion chromatography and toxicity assays. For the first time, it was shown that a combination of laccase and ultrasound treatments can have synergistic effects, which was shown by higher degradation rates. Bulk light absorption and ion-pairing high-performance liquid chromatography (IP-HPLC) were used for process monitoring, while with reversed-phase HPLC, a lower number of intermediates than expected by IP-HPLC was found. Liquid chromatography-mass spectrometry indicated that both acid orange dyes lead to a common end product due to laccase treatment. Acid Orange 52 is demethylated by laccase and ultrasound treatment. Further results confirmed that the main effect of ultrasound is based on ˙OH attack on the dye molecules.
Construction of a Cloning System for the Mass Production of a Virus-Binding Protein Specific for Poliovirus Type 1
Authors: Sano Daisuke , Omura Tatsuo
Published: May 2005

In our previous study, virus-binding proteins (VBPs) demonstrating the ability to strongly bind poliovirus type 1 (PV1) were recovered from a bacterial culture derived from activated sludge. The isolated VBPs would be useful as viral adsorbents for water and wastewater treatments. The VBP gene of activated sludge bacteria was isolated, and the cloning system of the VBP was established. The isolation of the VBP gene from DNA libraries for activated sludge bacteria was achieved with the colony hybridization technique. The sequence of the VBP gene consisted of 807 nucleotides encoding 268 amino acids. Fifteen amino acid sequences were retrieved from 2,137,877 sequences by a homology search using the BLAST server at the National Center for Biotechnology Information. The protein encoded in the isolated genome was considered to be a newly discovered protein from activated sludge culture, because any sequences in protein databases were not perfectly matched with the sequence of the VBP. It was confirmed that
Escherichia coli
BL21 transformed by pRSET carrying the isolated VBP gene could extensively produce the VBP clones. Enzyme-linked immunosorbent assay (ELISA) revealed that the VBP clone exhibited the binding ability with intact particles of PV1. The equilibrium binding constant between PV1 and VBP in the ELISA well was estimated to be 2.1 × 10
7
(M
−1
), which also indicated that the VBP clones have a high affinity with the PV1 particle. The VBP cloning system developed in this study would make it possible to produce a mass volume of VBPs and to utilize them as a new material of the specific adsorbent in several technologies, including virus removal, concentration, and detection.
Molecular Identification and Analysis ofBorrelia burgdorferiSensu Lato in Lizards in the Southeastern United States
Authors: Clark Kerry , Hendricks Amanda , Burge David
Published: May 2005

Lyme borreliosis (LB) group spirochetes, collectively known asBorrelia burgdorferisensu lato, are distributed worldwide. Wild rodents are acknowledged as the most important reservoir hosts.Ixodes scapularisis the primary vector ofB. burgdorferisensu lato in the eastern United States, and in the southeastern United States, the larvae and nymphs mostly parasitize certain species of lizards. The primary aim of the present study was to determine whether wild lizards in the southeastern United States are naturally infected with Lyme borreliae. Blood samples obtained from lizards in Florida and South Carolina were tested for the presence of LB spirochetes primarily by usingB. burgdorferisensu lato-specific PCR assays that amplify portions of the flagellin (flaB), outer surface protein A (ospA), and 66-kDa protein (p66) genes. Attempts to isolate spirochetes from a small number of PCR-positive lizards failed. However, PCR amplification and sequence analysis of partialflaB,ospA, andp66gene fragments confirmed numerous strains ofB. burgdorferisensu lato, includingBorrelia andersonii,Borrelia bissettii, andB. burgdorferisensu stricto, in blood from lizards from both states.B. burgdorferisensu lato DNA was identified in 86 of 160 (54%) lizards representing nine species and six genera. The high infection prevalence and broad distribution of infection among different lizard species at different sites and at different times of the year suggest that LB spirochetes are established in lizards in the southeastern United States.
Rapid Biosensor for Detection of Antibiotic-Selective Growth of
Escherichia coli
Authors: Gfeller Karin Y. , Nugaeva Natalia , Hegner Martin
Published: May 2005

A rapid biosensor for the detection of bacterial growth was developed using micromechanical oscillators coated in common nutritive layers. The change in resonance frequency as a function of the increasing mass on a cantilever array forms the basis of the detection scheme. The calculated mass sensitivity according to the mechanical properties of the cantilever sensor is ∼50 pg/Hz; this mass corresponds to an approximate sensitivity of ∼100
Escherichia coli
cells. The sensor is able to detect active growth of
E. coli
cells within 1 h. The starting number of
E. coli
cells initially attached to the sensor cantilever was, on average, ∼1,000 cells. Furthermore, this method allows the detection of selective growth of
E. coli
within only 2 h by adding antibiotics to the nutritive layers. The growth of
E. coli
was confirmed by scanning electron microscopy. This new sensing method for the detection of selective bacterial growth allows future applications in, e.g., rapid antibiotic susceptibility testing.
Differential Gene Expression Profiling of
Staphylococcus aureus
Cultivated under Biofilm and Planktonic Conditions
Authors: Resch Alexandra , Rosenstein Ralf , Nerz Christiane , Götz Friedrich
Published: May 2005

It
is well known that biofilm formation by pathogenic staphylococci on
implanted medical devices leads to “chronic polymer-associated
infections.” Bacteria in these biofilms are more resistant to
antibiotics and the immune defense system than their planktonic
counterparts, which suggests that the cells in a biofilm have altered
metabolic activity. To determine which genes are up-regulated in
Staphylococcus aureus
biofilm cells, we carried out a
comparative transcriptome analysis. Biofilm growth was simulated on
dialysis membranes laid on agar plates. Staphylococci were cultivated
planktonically in Erlenmeyer flasks with shaking. mRNA was isolated at
five time points from cells grown under both conditions and used for
hybridization with DNA microarrays. The gene expression patterns of
several gene groups differed under the two growth conditions. In
biofilm cells, the cell envelope appeared to be a very active
compartment since genes encoding binding proteins, proteins involved in
the synthesis of murein and glucosaminoglycan polysaccharide
intercellular adhesin, and other enzymes involved in cell envelope
synthesis and function were significantly up-regulated. In addition,
evidence was obtained that formate fermentation, urease activity, the
response to oxidative stress, and, as a consequence thereof, acid and
ammonium production are up-regulated in a biofilm. These factors might
contribute to survival, persistence, and growth in a biofilm
environment. Interestingly, toxins and proteases were up-regulated
under planktonic growth conditions. Physiological and biochemical tests
for the up-regulation of urease, formate dehydrogenase, proteases, and
the synthesis of staphyloxanthin confirmed the microarray
data.
Use of a Quartz Crystal Microbalance To Investigate the Antiadhesive Potential of
N
-Acetyl-
l
-Cysteine
Authors: Olofsson Ann-Cathrin , Hermansson Malte , Elwing Hans
Published: May 2005

The reduction of bacterial biofilm formation on stainless steel surfaces by
N
-acetyl-
l
-cysteine (NAC) is attributed to effects on bacterial growth and polysaccharide production, as well as an increase in the wettability of steel surfaces. In this report, we show that NAC-coated stainless steel and polystyrene surfaces affect both the initial adhesion of
Bacillus cereus
and
Bacillus subtilis
and the viscoelastic properties of the interaction between the adhered bacteria and the surface. A quartz crystal microbalance with dissipation was shown to be a powerful and sensitive technique for investigating changes in the applied NAC coating for initial cell surface interactions of bacteria. The kinetics of frequency and dissipation shifts were dependent on the bacteria, the life cycle stage of the bacteria, and the surface. We found that exponentially grown cells gave rise to a positive frequency shift as long as their cell surface hydrophobicity was zero. Furthermore, when the characteristics of binding between the cell and the surface for different growth phases were compared, the rigidity increased from exponentially grown cells to starved cells. There was a trend in which an increase in the viscoelastic properties of the interaction, caused by the NAC coating on stainless steel, resulted in a reduction in irreversibly adhered cells. Interestingly, for
B. cereus
that adhered to polystyrene, the viscoelastic properties decreased, while there was a reduction in adhered cells, regardless of the life cycle stage. Altogether, NAC coating on surfaces was often effective and could both decrease the initial adhesion and increase the detachment of adhered cells and spores. The most effective reduction was found for
B. cereus
spores, for which the decrease was caused by a combination of these two parameters.
Transcriptome Analysis of Recombinant Protein Secretion by
Aspergillus nidulans
and the Unfolded-Protein Response In Vivo
Authors: Sims Andrew H. , Gent Manda E. , Lanthaler Karin , Dunn-Coleman Nigel S. , Oliver Stephen G. , Robson Geoffrey D.
Published: May 2005

Filamentous fungi have a high capacity for producing large amounts of secreted proteins, a property that has been exploited for commercial production of recombinant proteins. However, the secretory pathway, which is key to the production of extracellular proteins, is rather poorly characterized in filamentous fungi compared to yeast. We report the effects of recombinant protein secretion on gene expression levels in
Aspergillus nidulans
by directly comparing a bovine chymosin-producing strain with its parental wild-type strain in continuous culture by using expressed sequence tag microarrays. This approach demonstrated more subtle and specific changes in gene expression than those observed when mimicking the effects of protein overproduction by using a secretion blocker. The impact of overexpressing a secreted recombinant protein more closely resembles the unfolded-protein response in vivo.
Enumeration of Respiring
Pseudomonas
spp. in Milk within 6 Hours by Fluorescence In Situ Hybridization following Formazan Reduction
Authors: Kitaguchi Akiko , Yamaguchi Nobuyasu , Nasu Masao
Published: May 2005

Respiring
Pseudomonas
spp. in milk were quantified within 6 h by fluorescence in situ hybridization (FISH) with vital staining. FISH with an oligonucleotide probe based on 16S rRNA sequences was used for the specific detection of
Pseudomonas
spp. at the single cell level. 5-Cyano-2,3-ditolyl tetrazolium chloride (CTC) was used to estimate bacterial respiratory activity. The numbers of respiring
Pseudomonas
cells as determined by FISH with CTC staining (CTC-FISH) were almost the same or higher than the numbers of CFU as determined by the conventional culture method.
Dose Determination for Acute
Salmonella
Infection in Pigs
Authors: Loynachan A. T. , Harris D. L.
Published: May 2005

Pigs were exposed to various levels of
Salmonella enterica
subsp.
enterica
serovar Typhimurium by either intranasal inoculation or by subjecting them to a contaminated environment. More than 10
3
salmonellae were required to induce acute
Salmonella
infection. These results indicate that intervention against acute
Salmonella
infection in lairage may be more readily achieved than previously thought.
Ischemia–reperfusion injury stimulates gelatinase expression and activity in kidney glomeruli
Authors: Caron Annick , Desrosiers Richard R , Langlois Stéphanie , Béliveau Richard
Published: May 2005

Although ischemia remains the leading cause of acute renal failure in humans, there is little information on the expression and activities of gelatinases of kidney glomeruli during ischemia–reperfusion injury. In this study, we used a unilateral ischemia–reperfusion model to investigate the activity and expression of gelatinases in glomeruli during acute ischemia. Unilateral ischemia was induced in rats by vascular clamping (30 min) followed by reperfusion (60 min) and isolation of glomeruli. The activity and expression of gelatinase proteins were determined by gelatin zymography and Western blotting. Gelatinase mRNA levels were evaluated by reverse transciptase-PCR. Ischemia and reperfusion increased serum creatinine levels, hallmark of acute renal failure. Ischemia induced mRNA and protein MMP-2 expression. There was strong stimulation of MMP-9 mRNA, both forms of dimeric MMP-9, and active mono meric MMP-9. In contrast to TIMP-1 decreasing, TIMP-2 protein and mRNA increased during ischemia. During reperfusion, there was a gradual reversal of the MMP-2 and MMP-9 levels and a strong inhibition of TIMP-1 and TIMP-2 at the protein and mRNA levels. Endocytic receptor LRP was increased during ischemia and returned to normal during reperfusion. Expression of MMP-9 docking receptor CD-44 was increased during reperfusion. Finally, ZO-1, an in vivo MMP-9 substrate, was degraded during ischemia, revealing that MMP-9 upregulated during ischemia was functional. Our data suggest that stimulation of gelatinase activity during ischemia could contribute to glomeruli injury, providing new therapeutic targets for acute renal failure in humans. In contrast, elevated monomeric MMP-9 activity due to TIMP-1 decrease during reperfusion may participate to glomerular recovery.Key words: gelatinases, ischemia-reperfusion, TIMPs, ZO-1, CD-44, LRP, glomeruli.
Activities of antioxidant enzymes in two stages of pathology development in sucrose-fed rats
Authors: Baños Guadalupe , Medina-Campos Omar N , Maldonado Perla D , Zamora José , Pérez Israel , Pavón Natalia , Pedraza-Chaverrí José
Published: May 2005

The activities of catalase in liver, heart and kidney as well as glutathione peroxidase and superoxide dismutase in liver, heart, kidney, and serum from hypertriglyceridemic and hypertensive female and male rats were measured at 3 and 8 months of daily administration of sucrose in their drinking water. This treatment induces high levels of serum triglycerides, central obesity, moderate hypertension, hyperinsulinemia, and an increase in lipoper oxida tion, among other alterations. The experimental periods were chosen on the basis of previous observations: at 3 months the level of serum triglycerides increases significantly above the normal value and remains without major changes thereafter, but the blood pressure only rises significantly at about 4 months in males and 5 months in females. So, at 8 months the rats have been subjected to abnormal conditions for 3–4 months. The effect of these and the influence of sex on levels of antioxidant enzymes were investigated. Both factors, sucrose treatment and sex, were conducive to significant changes in those variables.Key words: antioxidant enzymes, gender influence, hypertriglyceridemia, hypertension, sucrose-fed rats.
Proanthocyanidin from grape seeds enhances doxorubicin-induced antitumor effect and reverses drug resistance in doxorubicin-resistant K562/DOX cells
Authors: Zhang Xiao-Yu , Li Wen-Guang , Wu Yong-Jie , Bai De-Cheng , Liu Nai-Fa
Published: May 2005

With the aim of enhancing the efficacy of chemotherapeutic agents, we investigated the antitumor actions and reversal effect on drug resistance of proanthocyanidin plus doxorubicin. The results showed that proanthocyanidin 12.5~200 mg/L significantly inhibited proliferation of K562, K562/DOX, SPC-A-1, and Lewis cells in vitro in a time- and concentration-dependent manner, as determined by microculture tetrazolium assay. A combination of proantho cyani din 12.5, or 25 mg/L and doxorubicin treatment synergistically inhibited cell proliferation with decreased IC50 values. Proanthocyanidin reverses drug resistance in doxorubicin-resistant K562/DOX cells, and IC50 values were decreased by 9.19 (3.64~23.19), 2.56 (1.48~4.44), and 0.94 (0.81~1.09) mg/L, respectively, after 24 h treatment with doxorubicin 0.1~9.0 mg/L alone or in combination with proanthocyanidin 12.5 or 25 mg/L; the proanthocyanidin reversal fold was 3.6 and 9.8, respectively. Under confocal laser scanning microscope, the combination of proanthocyanidin 25 or 50 mg/L with doxorubicin 3 mg/L significantly increased the accumulation of intracellular doxorubicin, Ca2+, and Mg2+, and reduced the pH value and mitochondrial membrane potential in K562/DOX cells as compared with doxorubicin alone (p < 0.01). Additionally, the apoptosis rate was increased by 11.3% ± 3.3%, 14.2% ± 5.4%, and 23.8% ± 2.8%, respectively, for doxorubicin 3 mg/L alone or with proanthocyanidin 12.5 or 25 mg/L, as compared with controls (3.0% ± 1.4%), as demonstrated by flow cytometry. In vivo experiments demonstrated that i.p. administration of proanthocyanidin 10 mg/kg with doxorubicin 2 mg/kg had an inhibitory effect on the growth of transplantation tumor sarcoma 180 and hepatoma 22 in mice as compared with doxorubicin alone (p < 0.05). These results suggest that proanthocyanidin enhances doxorubicin-induced antitumor effect and reverses drug resistance, and its mechanism is attributed partially to the promotion of doxorubicin-induced apoptosis through an elevation of intracellular doxorubicin, and Ca2+, Mg2+ concentration, and a reduction of pH value and mitochondrial membrane potential.Key words: proanthocyanidin, doxorubicin, anti-tumor action, drug resistance.
SYMMETRY BREAKING IN GAUGE FIELD THEORY DUE TO NONCOMMUTATIVE SPACETIME
Authors: SIDHARTH B. G.
Published: May 2005

It is well known that a typical Yang–Mills Gauge Field is mediated by massless Bosons. It is only through a symmetry breaking mechanism, as in the Salam–Weinberg model that the quanta of such an interaction field acquire a mass in the usual theory. Here, we demonstrate that without taking recourse to the usual symmetry breaking mechanism, it is still possible to achieve this, given a noncommutative geometrical underpinning for spacetime.
VMC CALCULATIONS OF THE GROUND STATE PROPERTIES OF NUCLEAR MATTER
Authors: MANİSA KAAN , ATAV ÜLFET , OGUL RIZA
Published: May 2005

A Variational Monte Carlo method (VMC) is described for the evaluation of the ground state properties of nuclear matter. Equilibrium properties of symmetric nuclear matter and neutron matter are calculated by the described VMC method. The Urbana ν14 potential is used for the nucleon–nucleon interactions in the calculations. Three- and more-body interactions are included as a density dependent potential term. Total, kinetic and potential energies per particle are obtained for nuclear and neutron matter. Pressure values of nuclear and neutron matter are also calculated at various densities. The binding energy of nuclear matter is found to be -16.06 MeV at a saturation density of 0.16 fm -3. The results obtained are in good agreement with those obtained by various authors with different potentials and techniques.
IWBC ANALYSIS WITH QUASIMOLECULAR OPTICAL POTENTIALS
Authors: KHAN SOHAIL A.
Published: May 2005

The quasimolecular optical potential with Incoming Wave Boundary Condition model is used to obtain the fusion and elastic scattering cross-section at the sub-Coulomb region and above. This has been done for the 16 O +16 O and 12 C +12 C systems. It is found that sudden potentials describe well the average trend in the fusion and elastic scattering cross-section using the Incoming Wave Boundary Condition Method. Potentials fits for low energy are then used to obtain cross-sections at higher energies. Excellent agreement is obtained for the location of various peaks observed experimentally, especially in the case of 16 O +16 O . The parameters from these potentials give information on the nuclei in these dynamical situations. We find that a larger radius and a low density in the central region is required to explain the phenomena. The range of Yukawa potentials used are also larger by a factor of two as compared to those used by other authors.
RELATIVISTIC CORRECTIONS TO THE NUCLEAR AND NEUTRON MATTER ENERGY IN THE LOCV FRAMEWORK
Authors: ZARYOUNI S. , MOSHFEGH H. R.
Published: May 2005

We calculate the two-body relativistic boost interaction corrections as well as relativistic one-body and two-body kinetic energy corrections in cluster expansion of energy with AV18 and the new charge dependent Reid93 potentials within the lowest order constrained variational (LOCV) method. The equation of state of symmetric nuclear matter and pure neutron matter are calculated using the non-relativistic (H NR ), non-relativistic plus boost interaction corrections [Formula: see text] and [Formula: see text] plus kinetic energy corrections [Formula: see text] Hamiltonians. The relativistic boost interaction effects reduce the binding energies of symmetric nuclear matter for the AV18 interaction by ~3 MeV .
Communication Between Noncontacting Macromolecules
Authors: Völker Jens , Breslauer Kenneth J.
Published: May 2005

▪ Abstract  Molecular interactions are the language that molecules use to communicate recognition, binding, and regulation, events central to biological control mechanisms. Traditionally, such interactions involve direct, atom-to-atom, noncovalent contacts, or indirect contacts bridged by relatively fixed solvent molecules. Here we discuss a third class of molecular communication that, to date, has received less experimental attention, namely solvent-mediated communication between noncontacting macromolecules. This form of communication can be understood in terms of fundamental, well-established principles (coupled equilibria and linkage thermodynamics) that govern interactions between individual polymers and their solutions. In contrast to simple solutions used in laboratory studies, biological systems contain a multitude of nominally noninteracting biopolymers within the same solution environment. The exquisite control of biological function requires some form of communication between many of these solution components, even in the absence of direct and/or indirect contacts. Such communication must be considered when describing potential mechanisms of biological regulation.
Tracking Topoisomerase Activity at the Single-Molecule Level
Authors: Charvin G. , Strick T.R. , Bensimon D. , Croquette V.
Published: May 2005

▪ Abstract  The recent development of new techniques to manipulate single DNA molecules has opened new opportunities for the study of the enzymes that control DNA topology: the type I and II topoisomerases. These single-molecule assays provide a unique way to study the uncoiling of single supercoiled DNA molecules and the unlinking of two intertwined DNAs. They allow for a detailed characterization of the activity of topoisomerases, including the processivity, the chiral discrimination, and the dependence of their enzymatic rate on ATP concentration, degree of supercoiling, and the tension in the molecule. These results shed new light on the mechanism of these enzymes and their function in vivo.
Hemipterans as Plant Pathogens
Authors: Kaloshian Isgouhi , Walling Linda L.
Published: May 2005

Integration of the tools of genetics, genomics, and biochemistry has provided new approaches for identifying genes responding to herbivory. As a result, a picture of the complexity of plant-defense signaling to different herbivore feeding guilds is emerging. Plant responses to hemipteran insects have substantial overlap with responses mounted against microbial pathogens, as seen in changes in RNA profiles and emission of volatiles. Responses to known defense signals and characterization of the signaling pathways controlled by the first cloned insect R gene (Mi-1) indicate that perception and signal transduction leading to resistance may be similar to plant-pathogen interactions. Additionally, novel signaling pathways are emerging as important components of plant defense to insects. The availability of new tools and approaches will further enhance our understanding of the nature of defense in plant-hemipteran interactions.
RNA Silencing in Productive Virus Infections
Authors: MacDiarmid Robin
Published: May 2005

RNA silencing can reduce the expression of specific genes through posttranscriptional gene silencing, the microRNA pathway, and also through transcriptional gene silencing. Posttranscriptional gene silencing also acts as an antivirus mechanism. By suppressing this antivirus defense mechanism, viruses affect all three silencing pathways in addition to the intercellular signaling mechanism that transmits RNA-based messages throughout the plant. Productive virus infection may therefore disrupt the normal gene expression patterns in plants, resulting, at least in part, in a symptomatic phenotype. This review examines the cellular world that viruses exploit to provide some insight into the molecular interactions that occur during the virus infection cycle and how these produce the symptoms on infected plants.
Relative natural classes and relative injectivity
Authors: Crivei Septimiu
Published: May 2005

Let τ be a hereditary torsion theory on the category R‐Mod of left R‐modules over an associative unitary ring R. We introduce the notion of τ‐natural class as a class of modules closed under τ‐dense submodules, direct sums, and τ‐injective hulls. We study connections between certain conditions involving τ‐(quasi‐)injectivity in the context of τ‐natural classes, generalizing results established by S. S. Page and Y. Q. Zhou
(1994) for natural classes.
Asymptotic analysis of singular solutions of the scalar and mean curvature equations
Authors: García Gonzalo , Yaker Hendel
Published: May 2005

We show that positive solutions of a semilinear elliptic problem in the Sobolev critical exponent with Newmann conditions, related to conformal deformation of metrics in , are asymptotically symmetric in a neighborhood of the origin. As a consequence, we prove for a related problem of conformal deformation of metrics in that if a solution satisfies a Kazdan‐Warner‐type identity, then the conformal metric can be realized as a smooth metric on .
A refinement of normal approximation to Poisson binomial
Authors: Neammanee K.
Published: May 2005

Let X1, X2, …, Xn be independent Bernoulli random variables with P(Xj = 1) = 1 − P(Xj = 0) = pj and let Sn : = X1 + X2 + ⋯+Xn. Sn is called a Poisson binomial random variable and it is well known that the distribution of a Poisson binomial random variable can be approximated by the
standard normal distribution. In this paper, we use Taylor′s formula to improve the approximation by adding some correction terms. Our result is better than before and is of order 1/n in the case p1 = p2 = ⋯ = pn.
The incidence chromatic number of some graph
Authors: Xikui Liu , Yan Li
Published: May 2005

The concept of the incidence chromatic number of a graph was introduced by Brualdi and Massey (1993). They conjectured that every graph G can be incidence colored with Δ(G) + 2 colors. In this paper, we calculate the incidence chromatic numbers of the complete k‐partite graphs and give the incidence chromatic number of three infinite families of
graphs.
Simvastatin Versus Ezetimibe
Authors: Landmesser Ulf , Bahlmann Ferdinand , Mueller Maja , Spiekermann Stephan , Kirchhoff Nina , Schulz Svenja , Manes Costantina , Fischer Dieter , de Groot Kirsten , Fliser Danilo , Fauler Günter , März Winfried , Drexler Helmut
Published: May 2005

Background—

Statins may exert important pleiotropic effects, ie, improve endothelial function, independently of their impact on LDL cholesterol. In humans, however, pleiotropic effects of statins have never been unequivocally demonstrated because prolonged statin treatment always results in reduced LDL cholesterol levels. We therefore tested the hypothesis that similar reductions in LDL cholesterol with simvastatin and ezetimibe, a novel cholesterol absorption inhibitor, result in different effects on endothelial function.

Methods and Results—

Twenty patients with chronic heart failure were randomized to 4 weeks of simvastatin (10 mg/d) or ezetimibe (10 mg/d) treatment. Flow-dependent dilation (FDD) of the radial artery was determined by high-resolution ultrasound before and after intra-arterial vitamin C to determine the portion of FDD inhibited by radicals (ΔFDD-VC). Activity of extracellular superoxide dismutase, a major vascular antioxidant enzyme system, was determined after release from the endothelium by a heparin bolus injection. Endothelial progenitor cells were analyzed with an in vitro assay. Simvastatin and ezetimibe treatment reduced LDL cholesterol to a similar extent (15.6% versus 15.4%;
P
=NS), whereas changes in mevalonate, the product of HMG-CoA-reductase, differed between groups (Δmevalonate-simvastatin, −1.04±0.62 versus Δmevalonate-ezetimibe, 1.79±0.94 ng/mL;
P
<0.05 between groups). Importantly, FDD was markedly improved after simvastatin (10.5±0.6% versus 5.1±0.7%;
P
<0.01) but not after ezetimibe treatment (5.6±0.5% versus 5.8±0.6%;
P
=NS). ΔFDD-VC was substantially reduced after simvastatin but not after ezetimibe treatment. Extracellular superoxide dismutase activity was increased by >100% (
P
<0.05) after simvastatin but not ezetimibe treatment. Simvastatin treatment increased the number of functionally active endothelial progenitor cells, whereas ezetimibe had no effect.

Conclusions—

Four weeks of simvastatin treatment improves endothelial function independently of LDL cholesterol lowering, at least in part by reducing oxidant stress. Simvastatin may thereby exert important pleiotropic effects in humans.
Role of gp91
phox
(Nox2)-Containing NAD(P)H Oxidase in Angiogenesis in Response to Hindlimb Ischemia
Authors: Tojo Taiki , Ushio-Fukai Masuko , Yamaoka-Tojo Minako , Ikeda Satoshi , Patrushev Nikolay , Alexander R. Wayne
Published: May 2005

Background—

Neovascularization is potentially important for the treatment of ischemic heart and limb disease. We reported that reactive oxygen species (ROS) derived from gp91
phox
(Nox2)-containing NAD(P)H oxidase are involved in angiogenesis in mouse sponge models as well as in vascular endothelial growth factor (VEGF) signaling in cultured endothelial cells. The role of gp91
phox
-derived ROS in neovascularization in response to tissue ischemia is unknown, however.

Methods and Results—

Here, we show that neovascularization in the ischemic hindlimb is significantly impaired in gp91
phox−/−
mice as compared with wild-type (WT) mice as evaluated by laser Doppler flow, capillary density, and microsphere measurements. In WT mice, inflammatory cell infiltration in the ischemic hindlimb was maximal at 3 days, whereas capillary formation was prominent at 7 days when inflammatory cells were no longer detectable. Increased O
2
·−
production and gp91
phox
expression were present at both time points. The dihydroethidium staining of ischemic tissues indicates that O
2
·−
is mainly produced from inflammatory cells at 3 days and from neovasculature at 7 days after operation. Relative to WT mice, ischemia-induced ROS production in gp91
phox−/−
mice at both 3 and 7 days was diminished, whereas VEGF expression was enhanced and the inflammatory response was unchanged. Infusion of the antioxidant ebselen into WT mice also significantly blocked the increase in blood flow recovery and capillary density after ischemia.

Conclusions—

gp91
phox
-derived ROS play an important role in mediating neovascularization in response to tissue ischemia. NAD(P)H oxidases and their products are potential therapeutic targets for regulating angiogenesis in vivo.
Effect of Intensive Glycemic Control on Levels of Markers of Inflammation in Type 1 Diabetes Mellitus in the Diabetes Control and Complications Trial
Authors: Schaumberg Debra A. , Glynn Robert J. , Jenkins Alicia J. , Lyons Timothy J. , Rifai Nader , Manson JoAnn E. , Ridker Paul M. , Nathan David M.
Published: May 2005

Background—

Type 1 diabetes mellitus is associated with an increased risk of cardiovascular disease (CVD) that is not fully explained by conventional risk factors. The Diabetes Control and Complications Trial (DCCT) showed that intensive diabetes therapy reduced levels of LDL cholesterol and triglycerides but increased the risk of major weight gain, which might adversely affect CVD risk. The present study examined the effect of intensive therapy on levels of several markers of inflammation that have been linked to risk of CVD.

Methods and Results—

We measured levels of inflammatory biomarkers in stored baseline and 3-year follow-up serum specimens from a random sample of 385 participants in the DCCT, a multicenter trial in which 1441 subjects aged 13 to 39 years with type 1 diabetes mellitus were randomized to intensive or conventional diabetes treatment. The markers included high-sensitivity C-reactive protein (hsCRP), soluble intercellular adhesion molecule type 1 (sICAM-1), soluble vascular cell adhesion molecule type 1 (sVCAM-1), and the 55-kDa soluble tumor necrosis factor-α receptor 1 (sTNF-R1). We examined the effect of intensive therapy on the change in levels of the inflammatory markers. In unadjusted analyses, levels of hsCRP and sTNF-R1 increased in both treatment groups after 3 years of follow-up, with no significant difference between groups for hsCRP (
P
=0.53) but with a greater increase of sTNF-R1 in the intensive therapy group (
P
=0.002). In contrast, mean levels of sICAM-1 and sVCAM-1 decreased among participants assigned to intensive therapy, whereas they did not change among those in the conventional treatment group (
P
=0.03 for sICAM-1;
P
=0.03 for sVCAM-1). After adjustment for baseline levels and other factors, intensive therapy remained associated with a significant decrease in sICAM-1 (
P
=0.02) and an increase in sTNF-R1 (
P
=0.03). For hsCRP, there was a significant interaction between the top third of weight gain and treatment assignment (
P
=0.03). In subgroup analyses among subjects undergoing intensive therapy, hsCRP levels increased among those who gained the most weight, whereas it decreased among those in the bottom third of weight gain (
P
=0.0004).

Conclusions—

Intensive therapy in patients with type 1 diabetes mellitus reduced levels of sICAM-1 and increased levels of sTNF-R1 and of hsCRP among those who gained weight. These data demonstrate that the effect of intensive therapy on inflammation is complex and, to the extent that hsCRP is a risk factor, suggest that the risk of atherosclerosis among diabetic patients may be influenced by the degree of weight gain while undergoing intensive therapy.
Postinfarction Gene Therapy Against Transforming Growth Factor-β Signal Modulates Infarct Tissue Dynamics and Attenuates Left Ventricular Remodeling and Heart Failure
Authors: Okada Hideshi , Takemura Genzou , Kosai Ken-ichiro , Li Yiwen , Takahashi Tomoyuki , Esaki Masayasu , Yuge Kentaro , Miyata Shusaku , Maruyama Rumi , Mikami Atsushi , Minatoguchi Shinya , Fujiwara Takako , Fujiwara Hisayoshi
Published: May 2005

Background—

Fibrosis and progressive failure are prominent pathophysiological features of hearts after myocardial infarction (MI). We examined the effects of inhibiting transforming growth factor-β (TGF-β) signaling on post-MI cardiac fibrosis and ventricular remodeling and function.

Methods and Results—

MI was induced in mice by left coronary artery ligation. An adenovirus harboring soluble TGF-β type II receptor (Ad.CAG-sTβRII), a competitive inhibitor of TGF-β, was then injected into the hindlimb muscles on day 3 after MI (control, Ad.CAG-LacZ). Post-MI survival was significantly improved among sTβRII-treated mice (96% versus control at 71%), which also showed a significant attenuation of ventricular dilatation and improved function 4 weeks after MI. At the same time, histological analysis showed reduced fibrous tissue formation. Although MI size did not differ in the 2 groups, MI thickness was greater and circumference was smaller in the sTβRII-treated group; within the infarcted area, α-smooth muscle actin–positive cells were abundant, which might have contributed to infarct contraction. Apoptosis among myofibroblasts in granulation tissue during the subacute stage (10 days after MI) was less frequent in the sTβRII-treated group, and sTβRII directly inhibited Fas-induced apoptosis in cultured myofibroblasts. Finally, treatment of MI-bearing mice with sTβRII was ineffective if started during the chronic stage (4 weeks after MI).

Conclusions—

Postinfarction gene therapy aimed at suppressing TGF-β signaling mitigates cardiac remodeling by affecting cardiac fibrosis and infarct tissue dynamics (apoptosis inhibition and infarct contraction). This suggests that such therapy may represent a new approach to the treatment of post-MI heart failure, applicable during the subacute stage.