bluuebunny/crossref_metadata_2025 huggingface dataset:
Reduced Contamination by the
Fusarium
Mycotoxin Zearalenone in Maize Kernels through Genetic Modification with a Detoxification Gene
Authors: Igawa Tomoko , Takahashi-Ando Naoko , Ochiai Noriyuki , Ohsato Shuichi , Shimizu Tsutomu , Kudo Toshiaki , Yamaguchi Isamu , Kimura Makoto
Published: January 2007

Maize is subject to ear rot caused by toxigenic
Aspergillus
and
Fusarium
species, resulting in contamination with aflatoxins, fumonisins, trichothecenes, and zearalenone (ZEN). The trichothecene group and ZEN mycotoxins are produced by the cereal pathogen
Fusarium graminearum
. A transgenic detoxification system for the elimination of ZEN was previously developed using an
egfp
::
zhd101
gene (
gfzhd101
), encoding an enhanced green fluorescent protein fused to a ZEN-degrading enzyme. In this study, we produced a transgenic maize line expressing an intact copy of
gfzhd101
and examined the feasibility of transgene-mediated detoxification in the kernels. ZEN-degrading activity has been detected in transgenic kernels during seed maturation (for a period of 6 weeks after pollination). The level of detoxification activity was unaltered after an additional storage period of 16 weeks at 6°C. When the seeds were artificially contaminated by immersion in a ZEN solution for 48 h at 28°C, the total amount of the mycotoxin in the transgenic seeds was uniformly reduced to less than 1/10 of that in the wild type. The ZEN in the transgenic maize kernels was also efficiently decontaminated under conditions of lower water activity (a
w
) and temperature; e.g., 16.9 μg of ZEN was removed per gram of seed within 48 h at an a
w
of 0.90 at 20°C.
F. graminearum
infection assays demonstrated an absence of ZEN in the transgenic maize seeds, while the mycotoxin accumulated in wild-type kernels under the same conditions. Transgene-mediated detoxification may offer simple solutions to the problems of mycotoxin contamination in maize.
Air-Liquid Interface Biofilms of
Bacillus cereus
: Formation, Sporulation, and Dispersion
Authors: Wijman Janneke G. E. , de Leeuw Patrick P. L. A. , Moezelaar Roy , Zwietering Marcel H. , Abee Tjakko
Published: January 2007

Biofilm formation by
Bacillus cereus
was assessed using 56 strains of
B. cereus
, including the two sequenced strains, ATCC 14579 and ATCC 10987. Biofilm production in microtiter plates was found to be strongly dependent on incubation time, temperature, and medium, as well as the strain used, with some strains showing biofilm formation within 24 h and subsequent dispersion within the next 24 h. A selection of strains was used for quantitative analysis of biofilm formation on stainless steel coupons. Thick biofilms of
B. cereus
developed at the air-liquid interface, while the amount of biofilm formed was much lower in submerged systems. This suggests that
B. cereus
biofilms may develop particularly in industrial storage and piping systems that are partly filled during operation or where residual liquid has remained after a production cycle. Moreover, depending on the strain and culture conditions, spores constituted up to 90% of the total biofilm counts. This indicates that
B. cereus
biofilms can act as a nidus for spore formation and subsequently can release their spores into food production environments.
Expression of Plant Flavor Genes in
Lactococcus lactis
Authors: Hernández Igor , Molenaar Douwe , Beekwilder Jules , Bouwmeester Harro , van Hylckama Vlieg Johan E. T.
Published: January 2007

Lactic acid bacteria, such as
Lactococcus lactis
, are attractive hosts for the production of plant-bioactive compounds because of their food grade status, efficient expression, and metabolic engineering tools. Two genes from strawberry (
Fragaria x ananassa
), encoding an alcohol acyltransferase (SAAT) and a linalool/nerolidol synthase (FaNES), were cloned in
L. lactis
and actively expressed using the nisin-induced expression system. The specific activity of SAAT could be improved threefold (up to 564 pmol octyl acetate h
−1
mg protein
−1
) by increasing the concentration of tRNA
1
Arg
, which is a rare tRNA molecule in
L. lactis
. Fermentation tests with GM17 medium and milk with recombinant
L. lactis
strains expressing SAAT or FaNES resulted in the production of octyl acetate (1.9 μM) and linalool (85 nM) to levels above their odor thresholds in water. The results illustrate the potential of the application of
L. lactis
as a food grade expression platform for the recombinant production of proteins and bioactive compounds from plants.
Analysis of the Mechanism and Regulation of Lactose Transport and Metabolism in
Clostridium acetobutylicum
ATCC 824
Authors: Yu Yang , Tangney Martin , Aass Hans C. , Mitchell Wilfrid J.
Published: January 2007

Although the acetone-butanol-ethanol fermentation of
Clostridium acetobutylicum
is currently uneconomic, the ability of the bacterium to metabolize a wide range of carbohydrates offers the potential for revival based on the use of cheap, low-grade substrates. We have investigated the uptake and metabolism of lactose, the major sugar in industrial whey waste, by
C. acetobutylicum
ATCC 824. Lactose is taken up via a phosphoenolpyruvate-dependent phosphotransferase system (PTS) comprising both soluble and membrane-associated components, and the resulting phosphorylated derivative is hydrolyzed by a phospho-β-galactosidase. These activities are induced during growth on lactose but are absent in glucose-grown cells. Analysis of the
C. acetobutylicum
genome sequence identified a gene system,
lacRFEG
, encoding a transcriptional regulator of the DeoR family, IIA and IICB components of a lactose PTS, and phospho-β-galactosidase. During growth in medium containing both glucose and lactose,
C. acetobutylicum
exhibited a classical diauxic growth, and the
lac
operon was not expressed until glucose was exhausted from the medium. The presence upstream of
lacR
of a potential catabolite responsive element (
cre
) encompassing the transcriptional start site is indicative of the mechanism of carbon catabolite repression characteristic of low-GC gram-positive bacteria. A pathway for the uptake and metabolism of lactose by this industrially important organism is proposed.
Changing a Single Amino Acid in
Clostridium perfringens
β-Toxin Affects the Efficiency of Heterologous Secretion by
Bacillus subtilis
Authors: Nijland Reindert , Heerlien René , Hamoen Leendert W. , Kuipers Oscar P.
Published: January 2007

Achieving efficient heterologous protein production and secretion by
Bacillus subtilis
is an attractive prospect, although often disappointingly low yields are reached. The expression of detoxified
Clostridium perfringens
β-toxin (β-toxoid) is exemplary for this. Although β-toxin can be efficiently expressed and secreted by
Bacillus subtilis
, the genetically detoxified, and industrially interesting, β-toxoid variant is difficult to obtain in high amounts. To optimize the expression of this putative vaccine component, we studied the differences in the global gene regulation responses of
B. subtilis
to overproduction of either β-toxin or β-toxoid by transcriptomics. A clear difference was the upregulation of the CssRS regulon, known to be induced upon secretion stress, when β-toxoid is produced. YkoJ, a protein of unknown function, was also upregulated, and we show that its expression is dependent on
cssS
. We then focused on the heterologous protein itself and found that the major secretion bottleneck can be traced back to a single amino acid substitution between the β-toxin and the β-toxoid, which results in the rapid degradation of β-toxoid following secretion across the cytoplasmic membrane. In contrast to β-toxin, β-toxoid protein is more prone to degradation directly after secretion, most likely due to poor folding characteristics introduced with point mutations. Our results show that although the host can be adapted in many ways, the intrinsic properties of a heterologous protein can play a decisive role when optimizing heterologous protein production.
Efficient Extraction of Thioreodoxin from
Saccharomyces cerevisiae
by Ethanol
Authors: Inoue Yoshiharu , Nomura Wataru , Takeuchi Yoko , Ohdate Takumi , Tamasu Shogo , Kitaoka Atsushi , Kiyokawa Yoshifumi , Masutani Hiroshi , Murata Kazuo , Wakai Yoshinori , Izawa Shingo , Yodoi Junji
Published: January 2007

Thioredoxin, an antioxidant protein, is a promising molecule for development of functional foods because it protects the gastric mucosa and reduces the allergenicity of allergens. To establish a method for obtaining an ample amount of yeast thioredoxin, we found here that thioredoxin is released from
Saccharomyces cerevisiae
by treatment with 20% ethanol. We also found that Japanese sake contains a considerable amount of thioredoxin.
Identification and Characterization of
MFA1
, the Gene Encoding
Candida albicans
a
-Factor Pheromone
Authors: Dignard Daniel , El-Naggar Ahmed L. , Logue Mary E. , Butler Geraldine , Whiteway Malcolm
Published: January 2007

In the opaque state,
MTL
a
and
MTL
α strains of
Candida albicans
are able to mate, and this mating is directed by a pheromone-mediated signaling process. We have used comparisons of genome sequences to identify a
C. albicans
gene encoding a candidate
a
-specific mating factor. This gene is conserved in
Candida dubliniensis
and is similar to a three-gene family in the related fungus
Candida parapsilosis
but has extremely limited similarity to the
Saccharomyces cerevisiae MFA1
(Sc
MFA1
) and Sc
MFA2
genes. All these genes encode C-terminal CAAX box motifs characteristic of prenylated proteins. The
C. albicans
gene, designated Ca
MFA1
, is found on chromosome 2 between ORF19.2165 and ORF19.2219.
MFA1
encodes an open reading frame of 42 amino acids that is predicted to be processed to a 14-amino-acid prenylated mature pheromone. Microarray analysis shows that
MFA1
is poorly expressed in opaque
MTL
a
cells but is induced when the cells are treated with α-factor. Disruption of this
C. albicans
gene blocks the mating of
MTL
a
cells but not
MTL
α cells, while the reintegration of the gene suppresses this cell-type-specific mating defect.
A Possible Heterodimeric Prophage-Like Element in the Genome of the Insect EndosymbiontSodalis glossinidius
Authors: Clark Alvin J. , Pontes Mauricio , Jones Tait , Dale Colin
Published: January 2007

Extrachromosomal element pSOG3 (52,162 nucleotides) in the genome ofSodalis glossinidiuscontains redundant phage-related gene pairs, indicating that it may have been formed by the fusion of two ancestral phage genomes followed by gene degradation. We suggest that pSOG3 is a prophage that has undergone genome degeneration accompanying host adaptation to symbiosis.
Enzyme Diversity of the Cellulolytic System Produced by
Clostridium cellulolyticum
Explored by Two-Dimensional Analysis: Identification of Seven Genes Encoding New Dockerin-Containing Proteins
Authors: Blouzard Jean-Charles , Bourgeois Caroline , de Philip Pascale , Valette Odile , Bélaïch Anne , Tardif Chantal , Bélaïch Jean-Pierre , Pagès Sandrine
Published: January 2007

The enzyme diversity of the cellulolytic system produced by
Clostridium cellulolyticum
grown on crystalline cellulose as a sole carbon and energy source was explored by two-dimensional electrophoresis. The cellulolytic system of
C. cellulolyticum
is composed of at least 30 dockerin-containing proteins (designated cellulosomal proteins) and 30 noncellulosomal components. Most of the known cellulosomal proteins, including CipC, Cel48F, Cel8C, Cel9G, Cel9E, Man5K, Cel9M, and Cel5A, were identified by using two-dimensional Western blot analysis with specific antibodies, whereas Cel5N, Cel9J, and Cel44O were identified by using N-terminal sequencing. Unknown enzymes having carboxymethyl cellulase or xylanase activities were detected by zymogram analysis of two-dimensional gels. Some of these enzymes were identified by N-terminal sequencing as homologs of proteins listed in the NCBI database. Using Trap-Dock PCR and DNA walking, seven genes encoding new dockerin-containing proteins were cloned and sequenced. Some of these genes are clustered. Enzymes encoded by these genes belong to glycoside hydrolase families GH2, GH9, GH10, GH26, GH27, and GH59. Except for members of family GH9, which contains only cellulases, the new modular glycoside hydrolases discovered in this work could be involved in the degradation of different hemicellulosic substrates, such as xylan or galactomannan.
CadC Has a Global Translational Effect during Acid Adaptation in
Salmonella enterica
Serovar Typhimurium
Authors: Lee Yong Heon , Kim Bae Hoon , Kim Ji Hye , Yoon Won Suck , Bang Seong Ho , Park Yong Keun
Published: January 2007

In
Salmonella enterica
serovar Typhimurium, the membrane-localized CadC is a transcriptional activator of the
cadBA
operon, which contributes to the acid tolerance response. Unlike in
Escherichia coli
, in which transcription of
cadC
is constitutive, in
S. enterica
serovar Typhimurium
cadC
expression is induced by low pH and lysine. Inactivation of
cadC
suppresses the acid-sensitive phenotype of a
cadA
mutation, suggesting the existence of other CadC-dependent genes in addition to the
cadBA
operon. Using a proteomic approach, we identified 8 of the putative CadC-induced proteins and 15 of the putative CadC-repressed proteins. The former include porin proteins OmpC and OmpF. The latter include proteins involved in glycolysis, energy production, and stress tolerance. To better understand the altered levels of OmpC and OmpF, we compared expression of
ompR
in
S. enterica
serovar Typhimurium wild-type and
cadC
mutant strains and determined that CadC exerted a negative influence on
ompR
transcription. Taken together, our findings strongly suggest that CadC may be a global regulator involved in the OmpR regulatory system during acid adaptation.
The Lysine Decarboxylase CadA Protects
Escherichia coli
Starved of Phosphate against Fermentation Acids
Authors: Moreau Patrice L.
Published: January 2007

Conflicting results have been reported for the rate and extent of cell death during a prolonged stationary phase. It is shown here that the viability of wild-type cells (MG1655) could decrease ≥10
8
-fold between days 1 and 14 and between days 1 and 6 of incubation under aerobic and anaerobic phosphate (P
i
) starvation conditions, respectively, whereas the cell viability decreased moderately under ammonium and glucose starvation conditions. Several lines of evidence indicated that the loss of viability of P
i
-starved cells resulted primarily from the catabolism of glucose into organic acids through pyruvate oxidase (PoxB) and pyruvate-formate lyase (PflB) under aerobic and anaerobic conditions, respectively. Weak organic acids that are excreted into the medium can reenter the cell and dissociate into protons and anions, thereby triggering cell death. However, P
i
-starved cells were efficiently protected by the activity of the inducible GadABC glutamate-dependent acid resistance system. Glutamate decarboxylation consumes one proton, which contributes to the internal pH homeostasis, and removes one intracellular negative charge, which might compensate for the accumulated weak acid anions. Unexpectedly, the tolerance of P
i
-starved cells to fermentation acids was markedly increased as a result of the activity of the inducible CadBA lysine-dependent acid resistance system that consumes one proton and produces the diamine cadaverine. CadA plays a key role in the defense of
Salmonella
at pH 3 but was thought to be ineffective in
Escherichia coli
since the protection of
E. coli
challenged at pH 2.5 by lysine is much weaker than the protection by glutamate. CadA activity was favored in P
i
-starved cells probably because weak organic acids slowly reenter cells fermenting glucose. Since the environmental conditions that trigger the death of P
i
-starved cells are strikingly similar to the conditions that are thought to prevail in the human colon (i.e., a combination of low levels of P
i
and oxygen and high levels of carbohydrates, inducing the microbiota to excrete high levels of organic acids), it is tempting to speculate that
E. coli
can survive in the gut because of the activity of the GadABC and CadBA glutamate- and lysine-dependent acid resistance systems.
Metabolism of Linoleic Acid by Human Gut Bacteria: Different Routes for Biosynthesis of Conjugated Linoleic Acid
Authors: Devillard Estelle , McIntosh Freda M. , Duncan Sylvia H. , Wallace R. John
Published: January 2007

A survey of 30 representative strains of human gram-positive intestinal bacteria indicated that
Roseburia
species were among the most active in metabolizing linoleic acid (
cis
-9,
cis-
12-18:2). Different
Roseburia
spp. formed either vaccenic acid (
trans-
11-18:1) or a 10-hydroxy-18:1; these compounds are precursors of the health-promoting conjugated linoleic acid
cis-
9,
trans-
11-18:2 in human tissues and the intestine, respectively.
A Type IV-Secretion-Like System Is Required for Conjugative DNA Transport of Broad-Host-Range Plasmid pIP501 in Gram-Positive Bacteria
Authors: Abajy Mohammad Y. , Kopeć Jolanta , Schiwon Katarzyna , Burzynski Michal , Döring Mike , Bohn Christine , Grohmann Elisabeth
Published: January 2007

Plasmid pIP501 has a very broad host range for conjugative transfer among a wide variety of gram-positive bacteria and gram-negative
Escherichia coli
. Functionality of the pIP501 transfer (
tra
) genes in
E. coli
was proven by pIP501 retrotransfer to
Enterococcus faecalis
(B. Kurenbach, C. Bohn, J. Prabhu, M. Abudukerim, U. Szewzyk, and E. Grohmann, Plasmid
50:
86-93, 2003). The 15 pIP501
tra
genes are organized in a single operon (B. Kurenbach, J. Kopeć, M. Mägdefrau, K. Andreas, W. Keller, C. Bohn, M. Y. Abajy, and E. Grohmann, Microbiology
152:
637-645, 2006). The pIP501
tra
operon is negatively autoregulated at the transcriptional level by the conjugative DNA relaxase TraA. Three of the 15 pIP501-encoded Tra proteins show significant sequence similarity to the
Agrobacterium
type IV secretion system proteins VirB1, VirB4, and VirD4. Here we report a comprehensive protein-protein interaction map of all of the pIP501-encoded Tra proteins determined by the yeast two-hybrid assay. Most of the interactions were verified in vitro by isolation of the protein complexes with pull-down assays. In conjunction with known or postulated functions of the pIP501-encoded Tra proteins and computer-assisted prediction of their cellular location, we propose a model for the first type IV-secretion-like system encoded by a conjugative plasmid from gram-positive bacteria.
Porins Are Required for Uptake of Phosphates by
Mycobacterium smegmatis
Authors: Wolschendorf Frank , Mahfoud Maysa , Niederweis Michael
Published: January 2007

Phosphorus is an essential nutrient, but how phosphates cross the mycobacterial cell wall is unknown. Phosphatase activity in whole cells of
Mycobacterium smegmatis
was significantly lower than that in lysed cells, indicating that access to the substrate was restricted. The loss of the outer membrane (OM) porin MspA also reduced the phosphatase activity in whole cells compared to that in lysed cells. A similar result was obtained for
M. smegmatis
that overexpressed endogenous alkaline phosphatase, indicating that PhoA is not a surface protein, contrary to a previous report. The uptake of phosphate by a mutant lacking the porins MspA and MspC was twofold lower than that by wild-type
M. smegmatis
. Strikingly, the loss of these porins resulted in a severe growth defect of
M. smegmatis
on low-phosphate plates. We concluded that the OM of
M. smegmatis
represents a permeability barrier for phosphates and that Msp porins are the only OM channels for the diffusion of phosphate in
M. smegmatis
. However, phosphate diffusion through Msp pores is rather inefficient as shown by the 10-fold lower permeability of
M. smegmatis
for phosphate compared to that for glucose. This is likely due to the negative charges in the constriction zone of Msp porins. The phosphatase activity in whole cells of
Mycobacterium bovis
BCG was significantly less than that in lysed cells, indicating a similar uptake pathway for phosphates in slow-growing mycobacteria. However, porins that could mediate the diffusion of phosphates across the OM of
M. bovis
BCG and
Mycobacterium tuberculosis
are unknown.
The Novel Transcription Factor SgrR Coordinates the Response to Glucose-Phosphate Stress
Authors: Vanderpool Carin K. , Gottesman Susan
Published: January 2007

SgrR is the first characterized member of a family of bacterial transcription factors containing an N-terminal DNA binding domain and a C-terminal solute binding domain. Previously, we reported genetic evidence that SgrR activates the divergently transcribed gene
sgrS
, which encodes a small RNA required for recovery from glucose-phosphate stress. In this study, we examined the regulation of
sgrR
expression and found that SgrR negatively autoregulates its own transcription in the presence and absence of stress. An SgrR binding site in the
sgrR-sgrS
intergenic region is required in vivo for both SgrR-dependent activation of
sgrS
and autorepression of
sgrR
. Purified SgrR binds specifically to
sgrS
promoter DNA in vitro; a mutation in the site required for in vivo activation and autorepression abrogates in vitro SgrR binding. A plasmid library screen identified clones that alter expression of a P

sgrS

-lacZ
fusion; some act by titrating endogenous SgrR. The
yfdZ
gene, encoding a putative aminotransferase, was identified in this screen; the
yfdZ
promoter contains an SgrR binding site, and transcriptional fusions indicate that
yfdZ
is activated by SgrR. Clones containing
mlc
, which encodes a glucose-specific repressor protein, also downregulate P

sgrS

-lacZ
. The
mlc
clones do not appear to titrate the SgrR protein, indicating that Mlc affects
sgrS
expression by an alternative mechanism.
Cytological Analysis of the Mother Cell Death Process during Sporulation in
Bacillus subtilis
Authors: Hosoya Shigeo , Lu Zuolei , Ozaki Yousuke , Takeuchi Michio , Sato Tsutomu
Published: January 2007

We have identified the following events during the late stage in the mother cell in
Bacillus subtilis
: spore detachment from the polar site of the mother cell, membrane rupture, cell wall collapse, and release of the free spore. The membrane rupture was followed by mother cell lysis. Moreover, we found that NucB, an extracellular nuclease, is involved in DNA degradation after mother cell lysis.
Sinorhizobium meliloti
SyrA Mediates the Transcriptional Regulation of Genes Involved in Lipopolysaccharide Sulfation and Exopolysaccharide Biosynthesis
Authors: Keating David H.
Published: January 2007

Sinorhizobium meliloti
is a gram-negative soil bacterium found either in free-living form or as a nitrogen-fixing endosymbiont of leguminous plants such as
Medicago sativa
(alfalfa).
S. meliloti
synthesizes an unusual sulfate-modified form of lipopolysaccharide (LPS). A recent study reported the identification of a gene,
lpsS
, which encodes an LPS sulfotransferase activity in
S. meliloti
. Mutants bearing a disrupted version of
lpsS
exhibit an altered symbiosis, in that they elicit more nodules than wild type. However, under free-living conditions, the
lpsS
mutant displayed no change in LPS sulfation. These data suggest that the expression of
lpsS
is differentially regulated, such that it is transcriptionally repressed during free-living conditions but upregulated during symbiosis. Here, I show that the expression of
lpsS
is upregulated in strains that constitutively express the symbiotic regulator SyrA. SyrA is a small protein that lacks an apparent DNA binding domain and is predicted to be located in the cytoplasmic membrane yet is sufficient to upregulate
lpsS
transcription. Furthermore, SyrA can mediate the transcriptional upregulation of
exo
genes involved in the biosynthesis of the symbiotic exopolysaccharide succinoglycan. The SyrA-mediated transcriptional upregulation of
lpsS
and
exo
transcription is blocked in mutants harboring a mutation in
chvI
, which encodes the response regulator of a conserved two-component system. Thus, SyrA likely acts indirectly to promote transcriptional upregulation of
lpsS
and
exo
genes through a mechanism that requires the ExoS/ChvI two-component system.
Presence or Absence of Lipopolysaccharide O Antigens Affects Type III Secretion by
Pseudomonas aeruginosa
Authors: Augustin D. K. , Song Y. , Baek M. S. , Sawa Y. , Singh G. , Taylor B. , Rubio-Mills A. , Flanagan J. L. , Wiener-Kronish J. P. , Lynch S. V.
Published: January 2007

Pseudomonas aeruginosa
is one of the major causative agents of mortality and morbidity in hospitalized patients due to a multiplicity of virulence factors associated with both chronic and acute infections. Acute
P. aeruginosa
infection is primarily mediated by planktonic bacteria expressing the type III secretion system (TTSS), a surface-attached needle-like complex that injects cytotoxins directly into eukaryotic cells, causing cellular damage. Lipopolysaccharide (LPS) is the principal surface-associated virulence factor of
P. aeruginosa
. This molecule is known to undergo structural modification (primarily alterations in the A- and B-band O antigen) in response to changes in the mode of life (e.g., from biofilm to planktonic). Given that LPS exhibits structural plasticity, we hypothesized that the presence of LPS lacking O antigen would facilitate eukaryotic intoxication and that a correlation between the LPS O-antigen serotype and TTSS-mediated cytotoxicity would exist. Therefore, strain PAO1 (A
+
B
+
O-antigen serotype) and isogenic mutants with specific O-antigen defects (A
+
B
−
, A
−
B
+
, and A
−
B
−
) were examined for TTSS expression and cytotoxicity. A strong association existed in vitro between the absence of the large, structured B-band O antigen and increased cytotoxicity of these strains. In vivo, all three LPS mutant strains demonstrated significantly increased lung injury compared to PAO1. Clinical strains lacking the B-band O antigen also demonstrated increased TTSS secretion. These results suggest the existence of a cooperative association between LPS O-antigen structure and the TTSS in both laboratory and clinical isolates of
P. aeruginosa
.
Genome Sequence and Analysis of the Soil Cellulolytic ActinomyceteThermobifida fuscaYX
Authors: Lykidis Athanasios , Mavromatis Konstantinos , Ivanova Natalia , Anderson Iain , Land Miriam , DiBartolo Genevieve , Martinez Michele , Lapidus Alla , Lucas Susan , Copeland Alex , Richardson Paul , Wilson David B. , Kyrpides Nikos
Published: January 2007

Thermobifida fuscais a moderately thermophilic soil bacterium that belongs toActinobacteria. It is a major degrader of plant cell walls and has been used as a model organism for the study of secreted, thermostable cellulases. The complete genome sequence showed thatT. fuscahas a single circular chromosome of 3,642,249 bp predicted to encode 3,117 proteins and 65 RNA species with a coding density of 85%. Genome analysis revealed the existence of 29 putative glycoside hydrolases in addition to the previously identified cellulases and xylanases. The glycosyl hydrolases include enzymes predicted to exhibit mainly dextran/starch- and xylan-degrading functions.T. fuscapossesses two protein secretion systems: thesecgeneral secretion system and the twin-arginine translocation system. Several of the secreted cellulases have sequence signatures indicating their secretion may be mediated by the twin-arginine translocation system.T. fuscahas extensive transport systems for import of carbohydrates coupled to transcriptional regulators controlling the expression of the transporters and glycosylhydrolases. In addition to providing an overview of the physiology of a soil actinomycete, this study presents insights on the transcriptional regulation and secretion of cellulases which may facilitate the industrial exploitation of these systems.
TELEMEDICINE IN MALAYSIA AND INDONESIA: THE IMPORTANCE, OPPORTUNITIES AND CHALLENGES
Authors: OH TICK HUI , LIM HENG SIONG , BESAR ROSLI
Published: January 2007

Telemedicine is an emerging industry with the potential to revolutionize the delivery of healthcare for the benefit of consumers, providers and payors. In general, telemedicine refers to the use of information and telecommunication technologies to distribute both information and expertise necessary for healthcare service provision, collaboration or delivery among geographically separated participants — physicians and patients. In short, it is a generic term which is used to define various aspects of healthcare at a distance. Telemedicine has been heralded as one of several possible solutions to some of the medical dilemmas that are faced by many developing countries. In this paper, we will discuss the current state of telemedicine in developing countries in South-East Asia (SEA) in general, with Malaysia and Indonesia in particular.
IN VIVO LOCATION OF JOINT CENTERS OF THE SHOULDER SYSTEM: GLENO-HUMERAL AND SCAPULO-THORACIC JOINTS BETWEEN TWO POSTURES DESCRIBING THE ARM ELEVATION IN THE PLANE OF SCAPULA USING TECHNIQUES BASED UPON BIPLANAR RADIOGRAPHY
Authors: BERTHONNAUD ERIC , HERZBERG GUILLAUME , MORROW DUANE , AN KAI-NAN , DIMNET JOANNÈS
Published: January 2007

In biomechanics, the knowledge of accurate location of a joint center is essential because equilibration of the external loads and muscular forces about the joint is performed about this specific point. This paper focuses on the location of centers of gleno-humeral joint and scapulo-thoracic joint in a subject moving their arm in the scapular plane with a magnitude of 120°. Biplanar radiography with successive exposures has been used locating anatomical axes of bones. Geometric models of bones were defined allowing access to bone morphology by superposing model projections onto X-ray imaged bone contours. Functional models were used so as to represent the behavior in motion of shoulder joints. These techniques allowed us to access to results describing the linear and angular relative displacements of the shoulder bones between two different postures. The gleno-humeral and scapulo-thoracic finite joint centers (F H and F S ) are first defined through the location of the corresponding helical axis of motion (HAM) moving the joint from positions occupied in initial and final postures. The gleno-humeral and scapulo-thoracic mean joint centers (M H and M S ) are then calculated using a new technique, which defines that each joint center has the point having the smallest migrations while moving continuously from initial to final postures. This allows for the analysis of the linear and angular clearances, which affect joint center migration. The whole continuous movement has been parsed into several steps to test the stability of the mean joint center throughout the motion.
ON QUANTIZATION OF SYSTEMS WITH SECOND CLASS CONSTRAINTS
Authors: NURAMATOV A. G. , PROKHOROV L. V.
Published: January 2007

It is shown that quantization of the dynamical systems with second class constraints actually can be reduced to quantization of the systems with first class constraints. The motion of the non-relativistic particle along the plane curve and on a surface is considered. The results coincide with those of the "thin layer method". Influence of the non-physical variables on the physical sector is demonstrated.
GERBES AND HEISENBERG'S UNCERTAINTY PRINCIPLE
Authors: ISIDRO JOSÉ M.
Published: January 2007

We prove that a gerbe with a connection can be defined on classical phase space, taking the U(1)-valued phase of certain Feynman path integrals as Čech 2-cocycles. A quantisation condition on the corresponding 3-form field strength is proved to be equivalent to Heisenberg's uncertainty principle.
NEUMARK'S OPERATORS AND SHARP RECONSTRUCTIONS
Authors: BENEDUCI ROBERTO
Published: January 2007

Given a commutative POV measure [Formula: see text] on the Borel σ-algebra of the reals it is possible to construct a PV measure [Formula: see text] (the sharp reconstruction of F) such that the outcomes of the measurement of F can be interpreted as the random diffusion of the outcomes of the measurement of E. On the other hand Neumark's theorem ensures the existence of an extended Hilbert space [Formula: see text] and of a PV measure [Formula: see text] such that [Formula: see text] for every [Formula: see text]. We consider the projection [Formula: see text] of the self-adjoint operator [Formula: see text] corresponding to E+ and the self-adjoint operator A corresponding to the sharp reconstruction E and show the existence of a function G: [0,1] → [0,1] such that [Formula: see text]. An example for which the last relation can be inverted is shown.
A SOCIAL CYBERNETICS APPROACH TO COMMUNITY USE OF SPATIAL DATA FOR RESOURCE PROTECTION: FIELD STUDY ON A NORTH-CENTRAL IDAHO INDIAN RESERVATION
Authors: OWEN AMY , JANKOWSKI PIOTR , WILLIAMS BARBARA
Published: January 2007

This study investigates the engagement of communities with little or no GIS expertise in the use of publicly available spatial data for self-education in the protection of drinking water sources. A traditional administrative top-down approach to assisting communities in getting or using spatial information was replaced in the study with a bottom-up approach based on the principles of social cybernetics. The study investigated how communities used spatial datasets provided by the state to facilitate public participation in creating maps for water resource protection. Nine rural communities in the State of Idaho within the Nez Perce Indian Reservation participated in a field study from 2001–2002. Results included "map archetypes" developed by the communities and a validation of the bottom-up approach stressing community control over the process of using spatial data.
HOUSEHOLD ECOLOGICAL FOOTPRINTS — DEMOGRAPHICS AND SUSTAINABILITY
Authors: CAIRD SALLY , ROY ROBIN
Published: January 2007

How do demographic factors influence the environmental impacts of households? A major two year study used the ecological footprint technique to measure the environmental impacts of over 1000 UK households. Energy and transport were the biggest contributors to the 'footprint' of households. Rural, and adult households and households with few members had significantly larger per capita ecological footprints than urban/suburban households, households with children and households with several members. Although 11% of these UK households could be regarded as environmentally sustainable, the majority would require a reduction of 60% in ecological footprint to achieve a globally sustainable footprint per person. Consideration is given to the policy implications of demographic influences on household ecological footprints, including personal carbon allowances and house planning and design.
A STUDY ON ESTABLISHMENT OF EIA SYSTEM IN THE TAIWAN REGION
Authors: JOU JIN-JUH , LIAW SHU-LIANG
Published: January 2007

The purpose of Environmental Impact Assessment (EIA) is to systematically, objectively, scientificly and comprehensively collect data, analyze infromation, predict and assess the potential environmental effects of a development proposed by a private organization or a planning strategy developed by government, to make environmental management decisions. EIA process should be transparent, reasonable and allow relevant organizations, groups, local residents and other stakeholder to participate and to make comments. The developer and competent authority should ensure that the suggestions, comments, conclusions and consensus in the EIA process be implemented in the actual construction/application stage. The Environmental Impact Assessment Act for Taiwan Region was formulated and came into force in 1994. The scope of this study is to introduce the background of formation of EIA system in Taiwan Region and the concepts and features of the EIA regulations and legislations. The problems encontered in the implementation are discussed and measures to improve EIA procedures and targets and strategies of EIA applications are suggested. The experiences and suggestions may beneficial to those developing countries in developing their own EIA system.
Non-Nicotinic Therapies for Smoking Cessation
Authors: Siu Eric C.K. , Tyndale Rachel F.
Published: January 2007

Cigarette smoking is the primary cause of numerous preventable diseases; as such, the goals of smoking cessation are both to reduce health risks and to improve the quality of life. Currently, the first-line smoking cessation therapies include nicotine replacement products and bupropion. The nicotinic receptor partial agonist varenicline has recently been approved by the FDA for smoking cessation. A newer product currently under development and seeking approval by the FDA are nicotine vaccines. Clonidine and nortriptyline have demonstrated some efficacy but side effects may limit their use to second-line therapeutic products. Other therapeutic drugs that are under development include rimonabant, mecamylamine, monoamine oxidase inhibitors, and dopamine receptor D3 antagonists. Inhibitors of nicotine metabolism are also promising candidates for smoking reduction and cessation. In conclusion, promising new therapeutic products are emerging and they will provide smokers additional options to assist in achieving smoking cessation.
Polymorphic ventricular tachycardia and abnormal Ca2+handling in very-long-chain acyl-CoA dehydrogenase null mice
Authors: Werdich Andreas A. , Baudenbacher Franz , Dzhura Igor , Jeyakumar Loice H. , Kannankeril Prince J. , Fleischer Sidney , LeGrone Alison , Milatovic Dejan , Aschner Michael , Strauss Arnold W. , Anderson Mark E. , Exil Vernat J.
Published: January 2007

Patients with mutations in the mitochondrial very-long-chain acyl-CoA dehydrogenase (VLCAD) gene are at risk for cardiomyopathy, myocardial dysfunction, ventricular tachycardia (VT), and sudden cardiac death. The mechanism is not known. Here we report a novel mechanism of VT in mice lacking VLCAD (VLCAD−/−). These mice exhibited polymorphic VT and increased incidence of VT after isoproterenol infusion. Polymorphic VT was induced in 10 out of 12 VLCAD−/−mice (83%) when isoproterenol was used. One out of 10 VLCAD−/−mice with polymorphic VT had VT with the typical bidirectional morphology. At the molecular level, VLCAD−/−cardiomyocytes showed increased levels of cardiac ryanodine receptor 2, phospholamban, and calsequestrin with increased [3H]ryanodine binding in heart microsomes. At the single cardiomyocyte level, VLCAD−/−cardiomyocytes showed significant increase in diastolic indo 1 and fura 2 fluorescence, with increased Ca2+transient amplitude. These changes were associated with altered Ca2+dynamics, to include: faster sarcomere contraction, larger time derivative of the upstroke, and shorter time-to-minimum sarcomere length compared with VLCAD+/+control cells. The L-type Ca2+current characteristics were not different under voltage-clamp conditions in the two VLCAD genotypes. Sarcoplasmic reticulum Ca2+load measured as normalized integrated Na+/Ca2+exchange current after rapid caffeine application was increased by 48% in VLCAD−/−cells. We conclude that intracellular Ca2+handling represents a possible molecular mechanism of arrhythmias in mice and perhaps in VLCAD-deficient humans.
Overexpression of the Na+/H+exchanger and ischemia-reperfusion injury in the myocardium
Authors: Imahashi Kenichi , Mraiche Fatima , Steenbergen Charles , Murphy Elizabeth , Fliegel Larry
Published: January 2007

In the myocardium, the Na+/H+exchanger isoform-1 (NHE1) activity is detrimental during ischemia-reperfusion (I/R) injury, causing increased intracellular Na+(Nai+) accumulation that results in subsequent Ca2+overload. We tested the hypothesis that increased expression of NHE1 would accentuate myocardial I/R injury. Transgenic mice were created that increased the Na+/H+exchanger activity specifically in the myocardium. Intact hearts from transgenic mice at 10–15 wk of age showed no change in heart performance, resting intracellular pH (pHi) or phosphocreatine/ATP levels. Transgenic and wild-type (WT) hearts were subjected to 20 min of ischemia followed by 40 min of reperfusion. Surprisingly, the percent recovery of rate-pressure product (%RPP) after I/R improved in NHE1-overexpressing hearts (64 ± 5% vs. 41 ± 5% in WT; P < 0.05). In addition, NMR spectroscopy revealed that NHE1 overexpressor hearts contained higher ATP during early reperfusion (levels P < 0.05), and there was no difference in Na+accumulation during I/R between transgenic and WT hearts. HOE642 (cariporide), an NHE1 inhibitor, equivalently protected both WT and NHE1-overexpressing hearts. When hearts were perfused with bicarbonate-free HEPES buffer to eliminate the contribution of HCO3−transporters to pHiregulation, there was no difference in contractile recovery after reperfusion between controls and transgenics, but NHE1-overexpressing hearts showed a greater decrease in ATP during ischemia. These results indicate that the basal activity of NHE1 is not rate limiting in causing damage during I/R, therefore, increasing the level of NHE1 does not enhance injury and can have some small protective effects.
Influence of PKC-α overexpression on HSP70 and cardioprotection
Authors: Coaxum Sonya D. , Griffin Tina M. , Martin Jody L. , Mestril Ruben
Published: January 2007

Recent research has indicated that the protein kinase C (PKC) isoforms and the heat shock proteins (HSPs) are involved in cardioprotection. We have investigated the possible interaction between these two protein families. We have found that adenoviral-mediated expression of PKC-α in neonatal rat ventricular myocytes (NRVM) not only increases the expression of HSP70 but also protects against simulated ischemia-reperfusion. In addition, Western blots of PKC-α-infected NRVM indicated that other HSPs are not induced in the same manner as HSP70. In an effort to determine the mechanism of induction of HSP70 by PKC-α, we tested a chimeric construct that linked the luciferase reporter gene to the 5′-promoter region of HSP70 in myogenic H9c2 cells. When PKC-α was expressed, the 5′-promoter region of the HSP70 responded robustly, indicating that PKC-α induction of HSP70 expression is through transcription activation. Electrophoretic mobility shift assay determined that overexpression of PKC-α, PKC-δ, or PKC-ε did not induce activation of heat shock factor-1 (HSF-1). Therefore, induction of HSP70 by PKC-α is independent of heat shock factor-1 activation. We also measured cellular injury by assessing creatine kinase (CK) release from NRVM after simulated ischemia to determine cardioprotection. NRVM infected with the wild-type adenoviral construct AdwtPKC-α released 54% less CK than control NRVM. Experiments using small interfering RNA against HSP70 indicate that loss of PKC-α-induced HSP70 expression results in increased CK release or a loss of protection. Our results show that there is a close interaction between PKC-α and HSP70, independent of heat shock factor-1 activation, and that the protection conferred by PKC-α overexpression is mediated by the transcriptionally induced expression of HSP70.
PKC-α and TAK-1 are intermediates in the activation ofc-Jun NH2-terminal kinase by hypoxia-reoxygenation
Authors: Frazier Donna P. , Wilson Amber , Dougherty Christopher J. , Li Huifang , Bishopric Nanette H. , Webster Keith A.
Published: January 2007

c-Jun NH2-terminal kinase (JNK), a member of the MAPK family of protein kinases, is a stress-response kinase that is activated by proinflammatory cytokines and growth factors coupled to membrane receptors or through nonreceptor pathways by stimuli such as heat shock, UV irradiation, protein synthesis inhibitors, and conditions that elevate the levels of reactive oxygen intermediates (ROI). Ischemia followed by reperfusion or hypoxia with reoxygenation represents a condition of high oxidative stress where JNK activation is associated with elevated ROI. We recently demonstrated that the activation of JNK by this condition is initiated by ROI generated by mitochondrial electron transport and involves sequential activation of the proline-rich kinase 2 and the small GTP-binding factors Rac-1 and Cdc42. Here we present evidence that protein kinase C (PKC) and transforming growth factor-β-activated kinase-1 (TAK-1) are also components of this pathway. Inhibition of PKC with the broad-range inhibitor calphostin C, the PKC-α/β-selective inhibitor Go9367, or adenovirus-expressing dominant-negative PKC-α blocked the phosphorylation of proline-rich kinase 2 and JNK. Reoxygenation activated the mitogen-activated protein kinase kinase kinase, TAK-1, and promoted the formation of a complex containing Rac-1, TAK-1, and JNK but not apoptosis-stimulating kinase-1 or p21-activated kinase-1, which was detected within the first 10 min of reoxygenation. These results identify two new components, PKC and TAK-1, that have not been previously described in this signaling pathway.
Chronic preconditioning: a novel approach for cardiac protection
Authors: Wang Yigang , Ahmad Nauman , Wang Boyu , Ashraf Muhammad
Published: January 2007

Ischemic preconditioning is the most powerful protective mechanism known against lethal ischemia. Unfortunately, the protection lasts for only a few hours. Here we tested the hypothesis that the heart can be kept in a preconditioned state for constant protection against ischemia. In this study we chose BMS-191095 (BMS), a highly selective opener of mitochondrial ATP-sensitive K+(mitoKATP) channels. BMS (1 mg/kg ip) was administered to rats every 24 h until 96 h. In other groups, BMS plus wortmannin (WTN, 15 μg/kg ip), an inhibitor of the phosphatidylinositol 3-kinase (PI3-K), or BMS plus 5-hydroxydecanoic acid (5-HD, 5 mg/kg ip), an inhibitor of mitoKATP, or BMS plus Nω-nitro-l-arginine methyl ester (l-NAME) (30 μg/kg ip), an inhibitor of nitric oxide (NO) synthase, were administered to rats. Rats were then subjected to 30-min left anterior descending coronary artery occlusion and 120-min reperfusion. Cardiac function, infarct size, pathological changes, and apoptosis were assessed at the end of treatments. Saline-treated hearts displayed marked contractile dysfunction and underwent pathological changes. BMS-treated rats showed significant improvement in cardiac function, and infarct size was significantly reduced in BMS-treated hearts. However, protection by BMS was abolished by 5-HD, WTN, or l-NAME. These data demonstrate that hearts can be chronically preconditioned and retain their ability to remain resistant against lethal ischemia and that this protection is mediated by activation of mitoKATPvia NO and PI3-K/Akt signaling pathways.
Cigarette smoke-induced blockade of the mitochondrial respiratory chain switches lung epithelial cell apoptosis into necrosis
Authors: van der Toorn Marco , Slebos Dirk-Jan , de Bruin Harold G. , Leuvenink Henri G. , Bakker Stephan J. L. , Gans Rijk O. B. , Koëter Gerard H. , van Oosterhout Antoon J. M. , Kauffman Henk F.
Published: January 2007

Increased lung cell apoptosis and necrosis occur in patients with chronic obstructive pulmonary disease (COPD). Mitochondria are crucially involved in the regulation of these cell death processes. Cigarette smoke is the main risk factor for development of COPD. We hypothesized that cigarette smoke disturbs mitochondrial function, thereby decreasing the capacity of mitochondria for ATP synthesis, leading to cellular necrosis. This hypothesis was tested in both human bronchial epithelial cells and isolated mitochondria. Cigarette smoke extract exposure resulted in a dose-dependent inhibition of complex I and II activities. This inhibition was accompanied by decreases in mitochondrial membrane potential, mitochondrial oxygen consumption, and production of ATP. Cigarette smoke extract abolished the staurosporin-induced caspase-3 and -7 activities and induced a switch from epithelial cell apoptosis into necrosis. Cigarette smoke induced mitochondrial dysfunction, with compounds of cigarette smoke acting as blocking agents of the mitochondrial respiratory chain; loss of ATP generation leading to cellular necrosis instead of apoptosis is a new pathophysiological concept of COPD development.