bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of the rRNA Locus of
Pfiesteria piscicida
and Development of Standard and Quantitative PCR-Based Detection Assays Targeted to the Nontranscribed Spacer
Authors: Saito Keiko , Drgon Tomás , Robledo José A. F. , Krupatkina Danara N. , Vasta Gerardo R.
Published: April 2009

Pfiesteria piscicida
is a heterotrophic dinoflagellate widely distributed along the middle Atlantic shore of the United States and associated with fish kills in the Neuse River (North Carolina) and the Chesapeake Bay (Maryland and Virginia). We constructed a genomic DNA library from clonally cultured
P. piscicida
and characterized the nontranscribed spacer (NTS), small subunit, internal transcribed spacer 1 (ITS1), 5.8S region, ITS2, and large subunit of the rRNA gene cluster. Based on the
P. piscicida
ribosomal DNA sequence, we developed a PCR-based detection assay that targets the NTS. The assay specificity was assessed by testing clonal
P. piscicida
and
Pfiesteria shumwayae
, 35 additional dinoflagellate species, and algal prey (
Rhodomonas
sp.). Only
P. piscicida
and nine presumptive
P. piscicida
isolates tested positive. All PCR-positive products yielded identical sequences for
P. piscicida
, suggesting that the PCR-based assay is species specific. The assay can detect a single
P. piscicida
zoospore in 1 ml of water, 10 resting cysts in 1 g of sediment, or 10 fg of
P. piscicida
DNA in 1 μg of heterologous DNA. An internal standard for the PCR assay was constructed to identify potential false-negative results in testing of environmental sediment and water samples and as a competitor for the development of a quantitative competitive PCR assay format. The specificities of both qualitative and quantitative PCR assay formats were validated with >200 environmental samples, and the assays provide simple, rapid, and accurate methods for the assessment of
P. piscicida
in water and sediments.
SED1
Gene Length and Sequence Polymorphisms in Feral Strains of
Saccharomyces cerevisiae
Authors: Mannazzu Ilaria , Simonetti Emanuela , Marinangeli Paola , Guerra Emanuela , Budroni Marilena , Thangavelu Madan , Clementi Francesca
Published: April 2009

The
SED1
gene (YDR077W), coding for the major cell wall glycoprotein of
Saccharomyces cerevisiae
stationary-phase cells, contains two blocks of tandem repeat units located within two distinct regions of the nucleotide sequence. A PCR survey of the
SED1
open reading frames (ORFs) of 186 previously uncharacterized grape must isolates of
S. cerevisiae
yielded 13 PCR profiles arising from different combinations of seven
SED1
length variants in individuals homozygous or heterozygous for the gene. Comparison of the nucleotide sequences of a group of representatives of each of the seven length variants with those of S288C and the type strain, CBS1171, unequivocally identified them as
SED1
alleles and provided evidence for the presence of two minisatellite-like sequences, variable in length, within the ORF of an
S. cerevisiae
gene. The segregation analyses of the
SED1
length variants and other genetic markers in 13 isolates representative of each PCR profile suggested that molecular mechanisms involved in minisatellite expansion and contraction may be responsible for
SED1
heterozygosities within a population of homothallic must isolates of
S. cerevisiae.
Seasonality of Chesapeake Bay Bacterioplankton Species
Authors: Heidelberg J. F. , Heidelberg K. B. , Colwell R. R.
Published: April 2009

Bacteria,
γ-subclass of
Proteobacteria, Vibrio-Photobacterium, Vibrio vulnificus, Vibrio cholerae-Vibrio mimicus,
and
Vibrio cincinnatiensis
in water samples collected from the Choptank River in Chesapeake Bay from 15 April to 16 December 1996 were enumerated using a fluorescent oligonucleotide direct-counting (FODC) procedure. FODC results obtained using a
Bacteria
taxon-specific probe ranged from one-third the number of to the same number as that obtained by the acridine orange direct count (AODC) procedure. The abundance of individual taxa (per liter) ranged from 0.25 × 10
10
to 2.6 × 10
10
Bacteria,
0.32 × 10
8
to 3.1 × 10
8
γ-
Proteobacteria,
0.2 × 10
8
to 2.1 × 10
8
Vibrio-Photobacterium,
0.5 × 10
7
to 10 × 10
7
V. vulnificus,
0.2 × 10
6
to 6 × 10
6
V. cholerae-V. mimicus,
and 0.5 × 10
5
to 8 × 10
5
V. cincinnatiensis.
The occurrence of all taxa monitored in this study was higher in summer; however, these taxa made up a larger proportion of the
Bacteria
when the water temperature was low. Large fluctuations in species abundance as well as in percent composition of
Vibrio-Photobacterium
occurred from week to week, indicating that localized blooms of these taxa occur. The cross-Choptank River transect sample profile of
V. vulnificus
and
V. cholerae-V. mimicus
varied significantly in abundance, and trans-Choptank River transect samples revealed a patchy distribution.
Bacteria of the γ-Subclass
Proteobacteria
Associated with Zooplankton in Chesapeake Bay
Authors: Heidelberg J. F. , Heidelberg K. B. , Colwell R. R.
Published: April 2009

The seasonal abundance of γ-subclass
Proteobacteria, Vibrio-Photobacterium, Vibrio cholerae-Vibrio mimicus, Vibrio cincinnatiensis,
and
Vibrio vulnificus
in the Choptank River of Chesapeake Bay associated with zooplankton was monitored from April to December 1996. Large (>202-μm) and small (64- to 202-μm) size classes of zooplankton were collected, and the bacteria associated with each of the zooplankton size classes were enumerated by fluorescent oligonucleotide direct count. Large populations of bacteria were found to be associated with both the large and small size classes of zooplankton. Also, the species of bacteria associated with the zooplankton showed seasonal abundance, with the largest numbers occurring in the early spring and again in the summer, when zooplankton total numbers were correspondingly large. Approximately 0.01 to 40.0% of the total water column bacteria were associated with zooplankton, with the percentage of the total water column bacteria population associated with zooplankton varying by season. A taxonomically diverse group of bacteria was associated with zooplankton, and a larger proportion was found in and on zooplankton during the cooler months of the year, with selected taxa comprising a larger percent of the
Bacteria
in the summer.
V. cholerae-V. mimicus
and
V. vulnificus
comprised the bulk of the large and small zooplankton-associated
Vibrio-Photobacterium
species. In contrast,
V. cincinnatiensis
accounted for less than 0.1 to 3%. It is concluded that water column and zooplankton bacterial populations vary independently with respect to species composition since no correlation was observed between taxa occurring with highest frequency in the water column and those in association with zooplankton.
Robust Hydrocarbon Degradation and Dynamics of Bacterial Communities during Nutrient-Enhanced Oil Spill Bioremediation
Authors: Röling Wilfred F. M. , Milner Michael G. , Jones D. Martin , Lee Kenneth , Daniel Fabien , Swannell Richard J. P. , Head Ian M.
Published: April 2009

Degradation of oil on beaches is, in general, limited by the supply of inorganic nutrients. In order to obtain a more systematic understanding of the effects of nutrient addition on oil spill bioremediation, beach sediment microcosms contaminated with oil were treated with different levels of inorganic nutrients. Oil biodegradation was assessed respirometrically and on the basis of changes in oil composition. Bacterial communities were compared by numerical analysis of denaturing gradient gel electrophoresis (DGGE) profiles of PCR-amplified 16S rRNA genes and cloning and sequencing of PCR-amplified 16S rRNA genes. Nutrient amendment over a wide range of concentrations significantly improved oil degradation, confirming that N and P limited degradation over the concentration range tested. However, the extent and rate of oil degradation were similar for all microcosms, indicating that, in this experiment, it was the addition of inorganic nutrients rather than the precise amount that was most important operationally. Very different microbial communities were selected in all of the microcosms. Similarities between DGGE profiles of replicate samples from a single microcosm were high (95% ± 5%), but similarities between DGGE profiles from replicate microcosms receiving the same level of inorganic nutrients (68% ± 5%) were not significantly higher than those between microcosms subjected to different nutrient amendments (63% ± 7%). Therefore, it is apparent that the different communities selected cannot be attributed to the level of inorganic nutrients present in different microcosms. Bioremediation treatments dramatically reduced the diversity of the bacterial community. The decrease in diversity could be accounted for by a strong selection for bacteria belonging to the alkane-degrading
Alcanivorax/Fundibacter
group. On the basis of Shannon-Weaver indices, rapid recovery of the bacterial community diversity to preoiling levels of diversity occurred. However, although the overall diversity was similar, there were considerable qualitative differences in the community structure before and after the bioremediation treatments.
Enhancing Transport ofHydrogenophagaflavaENV735 for Bioaugmentation of Aquifers Contaminated with Methyltert-Butyl Ether
Authors: Streger Sheryl H. , Vainberg Simon , Dong Hailiang , Hatzinger Paul B.
Published: April 2009

The gasoline oxygenate methyltert-butyl ether (MTBE) has become a widespread contaminant in groundwater throughout the United States. Bioaugmentation of aquifers with MTBE-degrading cultures may be necessary to enhance degradation of the oxygenate in some locations. However, poor cell transport has sometimes limited bioaugmentation efforts in the past. The objective of this study was to evaluate the transport characteristics ofHydrogenophaga flavaENV735, a pure culture capable of growth on MTBE, and to improve movement of the strain through aquifer solids. The wild-type culture moved only a few centimeters in columns of aquifer sediment. An adhesion-deficient variant (H. flavaENV735:24) of the wild-type strain that moved more readily through sediments was obtained by sequential passage of cells through columns of sterile sediment. Hydrophobic and electrostatic interaction chromatography revealed that the wild-type strain is much more hydrophobic than the adhesion-deficient variant. Electrophoretic mobility assays and transmission electron microscopy showed that the wild-type bacterium contains two distinct subpopulations, whereas the adhesion-deficient strain has only a single, homogeneous population. Both the wild-type strain and adhesion-deficient variant degraded MTBE, and both were identified by 16S rRNA analysis as pure cultures ofH. flava. The effectiveness of surfactants for enhancing transport of the wild-type strain was also evaluated. Many of the surfactants tested were toxic to ENV735; however, one nonionic surfactant, Tween 20, enhanced cell transport in sand columns. Improving microbial transport may lead to a more effective bioaugmentation strategy for MTBE-contaminated sites where indigenous oxygenate degraders are absent.
Molecular Epidemiology of
Salmonella enterica
Serovar Typhimurium Isolates Determined by Pulsed-Field Gel Electrophoresis: Comparison of Isolates from Avian Wildlife, Domestic Animals, and the Environment in Norway
Authors: Refsum Thorbjørn , Heir Even , Kapperud Georg , Vardund Traute , Holstad Gudmund
Published: April 2009

The molecular epidemiology of 142 isolates of
Salmonella enterica
serovar Typhimurium from avian wildlife, domestic animals, and the environment in Norway was investigated using pulsed-field gel electrophoresis (PFGE) and computerized numerical analysis of the data. The bacterial isolates comprised 79 isolates from wild-living birds, including 46 small passerines and 26 gulls, and 63 isolates of nonavian origin, including 50 domestic animals and 13 environmental samples. Thirteen main clusters were discernible at the 90% similarity level. Most of the isolates (83%) were grouped into three main clusters. These were further divided into 20 subclusters at the 95% similarity level. Isolates from passerines, gulls, and pigeons dominated within five subclusters, whereas isolates from domestic animals and the environment belonged to many different subclusters with no predominance. The results support earlier results that passerines constitute an important source of infection to humans in Norway, whereas it is suggested that gulls and pigeons, based on PFGE analysis, represent only a minor source of human serovar Typhimurium infections. Passerines, gulls, and pigeons may also constitute a source of infection of domestic animals and feed plants or vice versa. Three isolates from cattle and a grain source, of which two were multiresistant, were confirmed as serovar Typhimurium phage type DT 104. These represent the first reported phage type DT 104 isolates from other sources than humans in Norway.
Donor Substrate Regeneration for Efficient Synthesis of Globotetraose and Isoglobotetraose
Authors: Shao Jun , Zhang Jianbo , Kowal Przemyslaw , Wang Peng George
Published: April 2009

Here we describe the efficient synthesis of two oligosaccharide moieties of human glycosphingolipids, globotetraose (GalNAcβ1→3Galα1→4Galβ1→4Glc) and isoglobotetraose (GalNAcβ1→3Galα1→3Galβ1→4Glc), with in situ enzymatic regeneration of UDP-N-acetylgalactosamine (UDP-GalNAc). We demonstrate that the recombinant β-1,3-N-acetylgalactosaminyltransferase fromHaemophilus influenzaestrain Rd can transferN-acetylgalactosamine to a wide range of acceptor substrates with a terminal galactose residue. The donor substrate UDP-GalNAc can be regenerated by a six-enzyme reaction cycle consisting of phosphoglucosamine mutase, UDP-N-acetylglucosamine pyrophosphorylase, phosphate acetyltransferase, pyruvate kinase, and inorganic pyrophosphatase fromEscherichia coli, as well as UDP-N-acetylglucosamine C4 epimerase fromPlesiomonas shigelloides. All these enzymes were overexpressed inE. coliwith six-histidine tags and were purified by one-step nickel-nitrilotriacetic acid affinity chromatography. Multiple-enzyme synthesis of globotetraose or isoglobotetraose with the purified enzymes was achieved with relatively high yields.
Gbu Glycine Betaine Porter and Carnitine Uptake in Osmotically Stressed
Listeria monocytogenes
Cells
Authors: Mendum Mary Lou , Smith Linda Tombras
Published: April 2009

The food-borne pathogen
Listeria monocytogenes
grows actively under high-salt conditions by accumulating compatible solutes such as glycine betaine and carnitine from the medium. We report here that the dominant transport system for glycine betaine uptake, the Gbu porter, may act as a secondary uptake system for carnitine, with a

K
m

of 4 mM for carnitine uptake and measurable uptake at carnitine concentrations as low as 10 μM. This porter has a

K
m

for glycine betaine uptake of about 6 μM. The dedicated carnitine porter, OpuC, has a

K
m

for carnitine uptake of 1 to 3 μM and a
V
max
of approximately 15 nmol/min/mg of protein. Mutants lacking either
opuC
or
gbu
were used to study the effects of four carnitine analogs on growth and uptake of osmolytes. In strain DP-L1044, which had OpuC and the two glycine betaine porters Gbu and BetL, triethylglycine was most effective in inhibiting growth in the presence of glycine betaine, but trigonelline was best at inhibiting growth in the presence of carnitine. Carnitine uptake through OpuC was inhibited by γ-butyrobetaine. Dimethylglycine inhibited both glycine betaine and carnitine uptake through the Gbu porter. Carnitine uptake through the Gbu porter was inhibited by triethylglycine. Glycine betaine uptake through the BetL porter was strongly inhibited by trigonelline and triethylglycine. These results suggest that it is possible to reduce the growth of
L. monocytogenes
under osmotically stressful conditions by inhibiting glycine betaine and carnitine uptake but that to do so, multiple uptake systems must be affected.
Cloning and Characterization of a Gene Cluster Involved in Cyclopentanol Metabolism in
Comamonas
sp. Strain NCIMB 9872 and Biotransformations Effected by
Escherichia coli
-Expressed Cyclopentanone 1,2-Monooxygenase
Authors: Iwaki Hiroaki , Hasegawa Yoshie , Wang Shaozhao , Kayser Margaret M. , Lau Peter C. K.
Published: April 2009

Cyclopentanone 1,2-monooxygenase, a flavoprotein produced by
Pseudomonas
sp. strain NCIMB 9872 upon induction by cyclopentanol or cyclopentanone (M. Griffin and P. W. Trudgill, Biochem. J. 129:595-603, 1972), has been utilized as a biocatalyst in Baeyer-Villiger oxidations. To further explore this biocatalytic potential and to discover new genes, we have cloned and sequenced a 16-kb chromosomal locus of strain 9872 that is herein reclassified as belonging to the genus
Comamonas
. Sequence analysis revealed a cluster of genes and six potential open reading frames designated and grouped in at least four possible transcriptional units as (
orf11-orf10-orf9)-(cpnE-cpnD-orf6-cpnC)-(cpnR-cpnB-cpnA)-(orf3-orf4
[partial 3′ end]
)
. The
cpnABCDE
genes encode enzymes for the five-step conversion of cyclopentanol to glutaric acid catalyzed by cyclopentanol dehydrogenase, cyclopentanone 1,2-monooxygenase, a ring-opening 5-valerolactone hydrolase, 5-hydroxyvalerate dehydrogenase, and 5-oxovalerate dehydrogenase, respectively. Inactivation of
cpnB
by using a
lacZ
-Km
r
cassette resulted in a strain that was not capable of growth on cyclopentanol or cyclopentanone as a sole carbon and energy source. The presence of σ
54
-dependent regulatory elements in front of the divergently transcribed
cpnB
and
cpnC
genes supports the notion that
cpnR
is a regulatory gene of the NtrC type. Knowledge of the nucleotide sequence of the
cpn
genes was used to construct isopropyl-β-thio-
d
-galactoside-inducible clones of
Escherichia coli
cells that overproduce the five enzymes of the
cpn
pathway. The substrate specificities of CpnA and CpnB were studied in particular to evaluate the potential of these enzymes and establish the latter recombinant strain as a bioreagent for Baeyer-Villiger oxidations. Although frequently nonenantioselective, cyclopentanone 1,2-monooxygenase was found to exhibit a broader substrate range than the related cyclohexanone 1,2-monooxygenase from
Acinetobacter
sp. strain NCIMB 9871. However, in a few cases opposite enantioselectivity was observed between the two biocatalysts.
Characterization of Serracin P, a Phage-Tail-Like Bacteriocin, and Its Activity against
Erwinia amylovora
, the Fire Blight Pathogen
Authors: Jabrane Abdelhamid , Sabri Ahmed , Compère Philippe , Jacques Philippe , Vandenberghe Isabel , Van Beeumen Jozef , Thonart Philippe
Published: April 2009

Serratia plymithicum
J7 culture supernatant displayed activity against many pathogenic strains of
Erwinia amylovora
, the causal agent of the most serious bacterial disease of apple and pear trees, fire blight, and against
Klebsiella pneumoniae, Serratia liquefaciens, Serratia marcescens,
and
Pseudomonas fluorescens.
This activity increased significantly upon induction with mitomycin C. A phage-tail-like bacteriocin, named serracin P, was purified from an induced culture supernatant of
S. plymithicum
J7. It was found to be the only compound involved in the antibacterial activity against sensitive strains. The N-terminal amino acid sequence analysis of the two major subunits (23 and 43 kDa) of serracin P revealed high homology with the Fels-2 prophage of
Salmonella enterica
, the coliphages P2 and 168, the φCTX prophage of
Pseudomonas aeruginosa,
and a prophage of
Yersinia pestis
. This strongly suggests a common ancestry for serracin P and these bacteriophages.
Function of Native OmtA In Vivo and Expression and Distribution of This Protein in Colonies of
Aspergillus parasiticus
Authors: Lee Li-Wei , Chiou Ching-Hsun , Linz John E.
Published: April 2009

The activities of two enzymes, a 168-kDa protein and a 40-kDa protein, OmtA, purified from the filamentous fungus
Aspergillus parasiticus
were reported to convert the aflatoxin pathway intermediate sterigmatocystin to
O-
methylsterigmatocystin in vitro. Our initial goal was to determine if OmtA is necessary and sufficient to catalyze this reaction in vivo and if this reaction is necessary for aflatoxin synthesis. We generated
A. parasiticus omtA
-null mutant LW1432 and a maltose binding protein-OmtA fusion protein expressed in
Escherichia coli
. Enzyme activity analysis of OmtA fusion protein in vitro confirmed the reported catalytic function of OmtA. Feeding studies conducted with LW1432 demonstrated a critical role for OmtA, and the reaction catalyzed by this enzyme in aflatoxin synthesis in vivo. Because of a close regulatory link between aflatoxin synthesis and asexual sporulation (conidiation), we hypothesized a spatial and temporal association between OmtA expression and conidiospore development. We developed a novel time-dependent colony fractionation protocol to analyze the accumulation and distribution of OmtA in fungal colonies grown on a solid medium that supports both toxin synthesis and conidiation. OmtA-specific polyclonal antibodies were purified by affinity chromatography using an LW1432 protein extract. OmtA was not detected in 24-h-old colonies but was detected in 48-h-old colonies using Western blot analysis; the protein accumulated in all fractions of a 72-h-old colony, including cells (0 to 24 h) in which little conidiophore development was observed. OmtA in older fractions of the colony (24 to 72 h) was partly degraded. Fluorescence-based immunohistochemical analysis conducted on thin sections of paraffin-embedded fungal cells from time-fractionated fungal colonies demonstrated that OmtA is evenly distributed among different cell types and is not concentrated in conidiophores. These data suggest that OmtA is present in newly formed fungal tissue and then is proteolytically cleaved as cells in that section of the colony age.
Uptake Rates of Oxygen and Sulfide Measured with Individual
Thiomargarita namibiensis
Cells by Using Microelectrodes
Authors: Schulz Heide N. , de Beer Dirk
Published: April 2009

Gradients of oxygen and sulfide measured towards individual cells of the large nitrate-storing sulfur bacterium
Thiomargarita namibiensis
showed that in addition to nitrate oxygen is used for oxidation of sulfide. Stable gradients around the cells were found only if acetate was added to the medium at low concentrations.
Regulation of
freA
,
acoA
,
lysF
, and
cycA
Expression by Iron Availability in
Aspergillus nidulans
Authors: Oberegger Harald , Schoeser Michelle , Zadra Ivo , Schrettl Markus , Parson Walther , Haas Hubertus
Published: April 2009

In the filamentous fungus
Aspergillus nidulans
, iron homeostasis is regulated at the transcriptional level by the negative-acting GATA factor SREA. In this study the expression of a putative heme-containing metalloreductase-encoding gene,
freA
, was found to be upregulated by iron limitation independently of SREA, demonstrating the existence of an iron-regulatory mechanism which does not involve SREA. In contrast to
freA
, various other genes encoding proteins in need of iron-containing cofactors—
acoA
,
lysF
, and
cycA
—were downregulated in response to iron depletion. Remarkably, SREA deficiency led to increased expression of
acoA
,
lysF
, and
cycA
under iron-replete growth conditions.
Evaluation of a Novel Therapeutic Approach to Treating Severe Pneumococcal Infection Using a Mouse Model
Authors: Melnick Nikkol , Rajam Gowrisankar , Carlone George M. , Sampson Jacquelyn S. , Ades Edwin W.
Published: April 2009

P4, a 28-amino-acid peptide, is a eukaryotic cellular activator that enhances specific in vitro opsonophagocytic killing of multiple bacterial pathogens. In a previous study, we successfully recreated this phenomenon in mice in vivo by using a two-dose regimen of P4 and pathogen-specific antibodies, which significantly reduced moribundity in mice. For the present study, we hypothesized that the inclusion of a low-dose antibiotic would make it possible to treat the infected mice with a single dose containing a mixture of P4 and a pathogen-specific antibody. A single dose consisting of P4, intravenous immunoglobulin (IVIG), and ceftriaxone effectively reduced moribundity compared to that of untreated controls (
n
= 10) by 75% (
P
< 0.05) and rescued all (10 of 10) infected animals (
P
< 0.05). If rescued animals were reinfected with
Streptococcus pneumoniae
and treated with a single dose containing P4, IVIG, and ceftriaxone, they could be rerescued. This observation of the repeated successful use of P4 combination therapy demonstrates a low risk of tolerance development. Additionally, we examined the polymorphonuclear leukocytes (PMN) derived from infected mice and observed that P4 enhanced in vitro opsonophagocytic killing (by >80% over the control level;
P
< 0.05). This finding supports our hypothesis that PMN are activated by P4 during opsonophagocytosis and the recovery of mice from pneumococcal infection. P4 peptide-based combination therapy may offer an alternative and rapid immunotherapy to treat fulminant pneumococcal infection.
Occupational exposure of UK adults to extremely low frequency magnetic fields
Authors: Mee T , Whatmough P , Broad L , Dunn C , Maslanyj M , Allen S , Muir K , McKinney P A , van Tongeren M
Published: April 2009

Background:

Occupational exposure to extremely low frequency (ELF) magnetic fields (MF) in the UK general population is poorly documented.

Aims:

To assess levels of occupational exposure to ELF MF in the UK and evaluate the use of a rigid job-exposure matrix (JEM) to assign exposures to subjects in the UK Adult Brain Tumour Study (UKABTS).

Methods:

Personal ELF MF measurements were carried out. Exposure traces were divided into occupational, travel and elsewhere periods, under differing exposure metrics. Exposure was classified by Standard Occupational Classification (2000), Standard Industrial Classification (1997), and a combined occupation-industry classification. Statistical analyses (mixed effects model) determined the contribution of occupational exposure to the 24 h cumulative exposure and the contribution of occupation and industry to total variance.

Results:

Data were obtained from 317 individuals, comprising UKABTS subjects (n = 192), occupational proxies for UKABTS subjects (n = 101) and “interest” readings (n = 24). 236 individuals provided occupational data covering 117 different occupations. Average exposure was significantly higher at work than at home. Elevated average occupational exposure was found for welding trades, printers, telephonists and filing and other records assistants. The discrimination of a rigid JEM based on occupation can be improved by linking the classification with industry and by the use of contextual information.

Conclusions:

This report substantially expands information on adult exposure to ELF MF in the UK. The accuracy of exposure assessments based solely on job codes is improved by linking with either industry code or contextual knowledge of equipment and of power lines or substations in the work environment.
The effect of plant growth-promoting rhizobacteria on asparagus seedlings and germinating seeds subjected to water stress under greenhouse conditions
Authors: Liddycoat Scott M. , Greenberg Bruce M. , Wolyn David J.
Published: April 2009

Plant growth-promoting rhizobacteria (PGPR) can have positive effects on vigour and productivity, especially under stress conditions. In asparagus ( Asparagus officinalis L.) field culture, seeds are planted in high-density nurseries, and 1-year-old crowns are transplanted to production fields. Performance can be negatively affected by water stress, transplant shock, and disease pressure on wounded roots. PGPR inoculation has the potential to alleviate some of the stresses incurred in the production system. In this study, the effects of PGPR ( Pseudomonas spp.) treatment were determined on 3-week-old greenhouse-grown seedlings and germinating seeds of 2 asparagus cultivars. The pots were irrigated to a predetermined level that resulted in optimum growth or the plants were subjected to drought or flooding stress for 8 weeks. The cultivars responded differently to PGPR: single inoculations of seedlings enhanced growth of ‘Guelph Millennium’ under optimum conditions and ‘Jersey Giant’ seedlings under drought stress. Seed inoculations with PGPR resulted in a positive response only for ‘Guelph Millennium’, for which both single or multiple inoculations enhanced plant growth under drought stress.
Evaluation of nitrogenous media components by Plackett–Burman statistical design for β-d-fructofuranosidase production by Saccharomyces sp. strain GVT263
Authors: Venkateshwar M. , Chaitanya K. , Altaf M. D. , Hameeda B. , Ghopal Reddy M.
Published: April 2009

β-d-Fructofuranosidase (FFase), an important enzyme of the confectionery and fructose syrup industry, is produced by several microorganisms. However, yeasts are the most used source because of their high sucrose fermentation capacity. In this work, production of FFase was carried out in submerged fermentation using a high enzyme-producing yeast strain. Plackett–Burman statistical experimental design was applied to evaluate the fermentation medium components. The effects of 10 nitrogen sources were studied in a 16-run experimental design. Beef extract, yeast extract, N-Z-amine, tryptone, meat extract, and ammonium acetate were found to have significant effects on enzyme production. Among these, yeast extract, N-Z-amine, and ammonium acetate were the most significant. A maximum FFase activity of 299.4 U/mL was obtained after a 24 h fermentation period.
INVESTIGATION OF THE INFLUENCE OF THE ELBOW JOINT REACTION ON THE PREDICTED MUSCLE FORCES USING DIFFERENT OPTIMIZATION FUNCTIONS
Authors: Raikova Rositsa T.
Published: April 2009

Less attention is paid to joint reactions when optimization tasks are solved aiming to predict individual muscle forces driving a biomechanical model. The reactions are important, however, for joint stability and for prevention from injuries, especially for fast motions and submaximal loading. The purpose of the paper is to investigate the influence of the joint reaction as a criterion in an objective function and to study the possibilities for prediction of antagonistic co-contraction. Planar elbow flexions in the sagittal plane with duration from 0.4 to 2 s are simulated, and muscle forces and elbow joint reaction are calculated solving numerically optimization tasks formulated for models with one (elbow moment equation only) and two (elbow and shoulder moment equations) degrees of freedom (DOF). The objective function is a weighted sum of muscle forces and joint reaction raised to different powers. The following conclusions can be made: (1) if the joint reaction is included in the objective function, antagonistic co-contraction can be predicted even for 1 DOF model; in some situations the use of such objective function can destroy the synergistic muscles' action; (2) the prediction of antagonistic muscles' co-contraction for 2 DOF model depends on the way the biarticular muscles are modeled, and this is valid for both dynamic and quasistatic conditions; if there are no biarticular muscles, antagonistic co-contraction cannot be predicted in one joint using popular objective functions, like minimum of sum of muscle forces or muscle stresses raised to a power.
ULTRASONOGRAPHY AND CLINICO-FUNCTIONAL PARAMETERS OF HEMIPLEGIC UPPER EXTREMITY IN A REHABILITATION SETTING
Authors: ADUNSKY ABRAHAM , MIZRAHI ELIYAHU , ARAD MARINA , HERSHKOWITZ MIRA , ZEILIG GABI , BLANKSTEIN ALEX
Published: April 2009

Background and aims: To study possible interrelations of clinical and functional parameters with ultrasonographic findings of shoulders of hemiplegic stroke patients. This would assist in determining the need for a possible ultrasound evaluation of hemiplegic shoulders. Methods: Prospective case series were studied in the Department of Geriatric Medicine and Rehabilitation, at a university-affiliated referral hospital. We studied a total of 26 consecutive stroke patients with hemiplegic shoulders undergoing a standard rehabilitation course. Hemiplegic shoulders were studied by ultrasound and scored for the number of pathological (positive) findings. Shoulder scores were correlated with various clinical and functional parameters (Ashworth score, Fugl-Meyer score, Functional Independence Measure) as non-dependent variables. Results: No correlation was found between any of the parameters we have studied and the ultrasonographic score, except for shoulder pain (p = 0.012). A regression analysis documented painful shoulder (p = 0.002) and spasticity (p = 0.039) as significantly associated with higher ultrasonographic scores. Conclusions: Ultrasound investigation of hemiplegic upper extremities does not interrelate with any of the parameters associated with rehabilitation outcome and should be reserved for those suffering painful and spastic hemiplegic shoulders.
ASSESSMENT OF GROUND REACTION FORCES OF STEPPAGE GAIT IN COMPARISON WITH NORMAL GAIT
Authors: Jamshidi Nima , Rostami Mostafa , Najarian Siamak , Menhaj Mohammad Bagher , Saadatnia Mohammad , Salami Firooz
Published: April 2009

Background: This pilot study aimed to assess quantitative differences between normal and steppage gait by analyzing force plate data. Materials and Methods: We studied 25 subjects with drop foot, who were treated in the orthopedic center for drop foot brace. Twenty healthy students were included as a control group. There were no differences in the age, weight, height, and body mass index between the patients and the controls (p > 0.05). They walked at self-selected speed with a mean of 10 trials (+2) to collect their ground reaction forces data by force plate. Results: There were no significant differences between the groups in antero-posterior component of ground reaction force (p > 0.05). There was significant relationship between the time parameters in vertical and medio-lateral components of ground reaction forces (p < 0.05). We have found that the medio-lateral impulse in the patients group is negative (p < 0.05), which means instability in patients' gait. Conclusion: The result of this research reveals that the analysis of ground reaction force quantitatively describes steppage gait. The average stance time among patients is longer than control group. Further work with a larger database of subjects is required to confirm our findings.
POSITIVE SOLUTIONS FOR ELLIPTIC EQUATIONS RELATED TO THE CAFFARELLI–KOHN–NIRENBERG INEQUALITIES
Authors: DENG YINBIN , JIN LINGYU , PENG SHUANGJIE
Published: April 2009

In this paper, we are concerned with the following elliptic problems which are related to the well-known Caffarelli–Kohn–Nirenberg inequalities: [Formula: see text] where a = b < 0, [Formula: see text], a ≤ d ≤ a + 1, a ≤ e ≤ a + 1, [Formula: see text], [Formula: see text], 2 < q < D, λ and η are real constants. We obtain positive solutions for problem (0.1). Moreover, we establish a corresponding Pohozaev identity for problem (0.1), from which, the nonexistence of positive solutions for problem (0.1) is obtained.
INFINITELY MANY EVEN PERIODIC SOLUTIONS OF LAGRANGIAN SYSTEMS ON ANY RIEMANNIAN TORI WITH EVEN POTENTIAL IN TIME
Authors: LU GUANGCUN , WANG MINGYAN
Published: April 2009

In this paper, we prove that the Lagrangian system on any Riemannian torus with C3-smooth even and τ-periodic potential in time possesses infinitely many different periodic contractible even solutions with integer multiple periods of τ. As a consequence, we get that the same conclusion holds for any τ > 0 and the Lagrangian system on any Riemannian torus with C3-smooth potential independent of time.
INVERSE SQUARE ROOT MOMENT SINGULARITIES IN RECTANGULAR PLATES CONTAINING AN INTERNAL LINE SUPPORT
Authors: SOMPORNJAROENSUK YOS , KIATTIKOMOL KRAIWOOD
Published: April 2009

Two cases of a rectangular plate having moment singularities at the ends of a partial internal line support are analytically investigated. The bending of the plate by uniform loading is formulated in terms of dual-series equations. Application of the finite Hankel integral transform reduces the dual-series equations to a Fredholm integral equation of the second kind that can be solved by standard techniques. Numerical results are given for the deflections and bending moments along the line outside of an internal line support and the change in strain energy due to the presence of a partial support.
B-SPLINE COLLOCATION METHOD FOR A SINGULARLY PERTURBED REACTION–DIFFUSION PROBLEM USING ARTIFICIAL VISCOSITY
Authors: KADALBAJOO MOHAN K. , ARORA PUNEET
Published: April 2009

In this paper, we develop a B-spline collocation method using artificial viscosity for solving a class of singularly perturbed reaction–diffusion equations. We use the artificial viscosity to capture the exponential features of the exact solution on a uniform mesh, and use the B-spline collocation method, which leads to a tridiagonal linear system. The convergence analysis is given and the method is shown to have uniform convergence of second order. The design of an artificial viscosity parameter is confirmed to be a crucial ingredient for simulating the solution of the problem. Known test problems have been studied to demonstrate the accuracy of the method. Numerical results show the behavior of the method, with emphasis on treatment of boundary conditions. Results shown by the method are found to be in good agreement with the exact solution.
Resurrected Pandemic Influenza Viruses
Authors: Tumpey Terrence M. , Belser Jessica A.
Published: April 2009

Influenza viruses continue to pose a major global public health problem. There is a need to better understand the pathogenicity and transmission of pandemic influenza viruses so that we may develop improved methods for their prevention and control. Reconstruction of the 1918 virus and studies elucidating the exceptional virulence and transmissibility of the virus are providing exciting new insights into this devastating pandemic strain. The primary approach has been to reconstruct and analyze recombinant viruses, in which genes of the 1918 virus are replaced with genes of contemporary influenza viruses of lesser virulence. This review highlights the current status of the field and discusses the molecular determinants of the 1918 pandemic virus that may have contributed to its virulence and spread. Identifying the exact genes responsible for the high virulence of the 1918 virus will be an important step toward understanding virulent influenza strains and will allow the world to better prepare for and respond to future influenza pandemics.
Arginine vasopressin regulation in pre- and postpubertal male rats by the androgen metabolite 3β-diol
Authors: Pak Toni R. , Chung Wilson C. J. , Hinds Laura R. , Handa Robert J.
Published: April 2009

Arginine vasopressin (AVP) is a nonapeptide expressed in several brain regions. In addition to its well-characterized role in osmoregulation, AVP regulates paternal behavior, aggression, circadian rhythms, and the stress response. In the bed nucleus of the stria terminalis (BST), AVP gene expression is tightly regulated by gonadal steroid hormones. However, the degree by which AVP is regulated by gonadal steroid hormones in the suprachiasmatic nucleus (SCN) and medial amygdala (MeA) is unclear. Previous studies have shown that AVP expression in the brain of gonadectomized rats is restored with testosterone, 17β-estradiol, and 5α-dihydrotestosterone (DHT) replacement. In addition, we have demonstrated that 3β-diol, a metabolite of DHT, increased AVP promoter activity in a neuronal cell line and that the effects of 3β-diol on AVP promoter activity were mediated by estrogen receptor-β. To test whether 3β-diol has a physiological role in the regulation of central AVP expression in vivo, we gonadectomized pre- and postpubertal male rats and followed with once daily injections of estradiol benzoate (EB), DHT-propionate, 3β-diol-dipropionate, or vehicle. The SCN, BST, and MeA were analyzed for AVP mRNA expression using in situ hybridization. In the BST, intact juveniles had significantly fewer AVP-expressing cells than adults. GDX abolished all AVP mRNA expression in the BST in both age groups, whereas treatment with EB restored >80% and DHTP <10% of the AVP expression. Interestingly, 3β-diol-proprionate was more effective at inducing AVP expression in juveniles than in adults, suggesting that the regulation of AVP by 3β-diol might be age dependent.
Transcription factors in the development of medial hypothalamic structures
Authors: Jo Young-Hwan , Chua Streamson
Published: April 2009

The hypothalamus has historically been subdivided into nuclei, agglomerations of cell bodies that are visually distinct in histological sections. Regulatory functions of metabolism have been assigned to the various hypothalamic nuclei principally by analysis of animals with lesions of individual nuclei ( 39 ) but also via various means of stimulation, such as cooling or heating probes. Biochemical and molecular specificity of these studies became possible with the identification and synthesis of neurotransmitters ( 7 , 38 ) as well as the means to manipulate the expression of endogenous neurotransmitters ( 35 , 37 ) and their receptors by genetic means ( 6 , 21 ). The arcuate nucleus (ARC) is likely to be the primary site for neurons that sense circulating fuels and energy reserves (POMC/CART neurons, NPY/AGRP neurons), whereas the paraventricular nucleus (PVN) receives input from the ARC and harbors many of the releasing factors (CRF, TRH, vasopressin, and oxytocin) that control pituitary hormone release. The ventromedial nucleus (VMN) receives input from the ARC and plays a critical role in energy balance in parallel with the ARC. The VMN and PVN also send descending projections to the autonomic nervous system and other pathways that control ingestive behavior and metabolism. Developmental analyses have revealed that the neurons that comprise the hypothalamic nuclei arise by differentiation and migration from stem cells within the ventricular zone. Based on recent work, it is becoming clear that coordination between numerous transcription factors that determine specification, survival, and migration is necessary for the formation of the hypothalamus, with each nucleus being determined by its own unique set of factors. In this minireview, we will provide a selective view of the roles that transcription factors play in the developing hypothalamus.
Oleic acid-induced ADRP expression requires both AP-1 and PPAR response elements, and is reduced by Pycnogenol through mRNA degradation in NMuLi liver cells
Authors: Fan Bin , Ikuyama Shoichiro , Gu Jian-Qiu , Wei Ping , Oyama Jun-ichi , Inoguchi Toyoshi , Nishimura Junji
Published: April 2009

Fatty acids stimulate lipid accumulation in parallel with increased expression of adipose differentiation-related protein (ADRP) in liver cells. Although it is generally considered that the fatty acid effect on ADRP expression is mediated by peroxisome proliferator-activated receptors (PPARs), we identified here an additional molecular mechanism using the NMuLi mouse liver nonparenchymal cell line, which expresses PPARγ and δ but not α. Oleic acid (OA) and specific ligands for PPARγ and -δ stimulated ADRP expression as well as the −2,090-bp ADRP promoter activity which encompasses the PPAR response element (PPRE) adjacent to an Ets/activator protein (AP)-1 site. When the AP-1 site was mutated, OA failed to stimulate the activity despite the presence of the PPRE, whereas ligands for PPARγ and -δ did stimulate it and so did a PPARα ligand under the coexpression of PPARα. DNA binding of AP-1 was stimulated by OA but not by PPAR ligands. Because we previously demonstrated that Pycnogenol (PYC), a French maritime pine bark extract, suppressed ADRP expression in macrophages partly by suppression of AP-1 activity, we tested the effect of PYC on NMuLi cells. PYC reduced the OA-induced ADRP expression along with suppression of lipid droplet formation. However, PYC neither suppressed the OA-stimulated ADRP promoter activity nor DNA binding of AP-1 but, instead, reduced the ADRP mRNA half-life. All these results indicate that the effect of OA on ADRP expression requires AP-1 as well as PPRE, and PYC suppresses the ADRP expression in part by facilitating mRNA degradation. PYC, a widely used dietary supplement, could be beneficial for the prevention of excessive lipid accumulation such as hepatic steatosis.
Actions of fibroblast growth factor-8 in bone cells in vitro
Authors: Lin Jian-Ming , Callon Karen E. , Lin Jun-Sheng , Watson Maureen , Empson Victoria , Tong Pak C. , Grey Andrew , Naot Dorit , Green Colin R. , Reid Ian R. , Cornish Jillian
Published: April 2009

The fibroblast growth factors (FGFs) are a group of at least 25 structurally related peptides that are involved in many biological processes. Some FGFs are active in bone, including FGF-1, FGF-2, and FGF-18, and recent evidence indicates that FGF-8 is osteogenic, particularly in mesenchymal stem cells. In the current study, we found that FGF-8 was expressed in rat primary osteoblasts and in osteoblastic UMR-106 and MC3T3-E1 cells. Both FGF-8a and FGF-8b potently stimulated the proliferation of osteoblastic cells, whereas they inhibited the formation of mineralized bone nodules in long-term cultures of osteoblasts and reduced the levels of osteoblast differentiation markers, osteocalcin, and bone sialoprotein. FGF-8a induced the phosphorylation of p42/p44 mitogen-activated protein kinase (MAPK) in osteoblastic cells; however, its mitogenic actions were not blocked by either the MAPK kinase (MEK) inhibitor U-0126 or the PI 3-kinase (PI3K) inhibitor LY-294002. Interestingly, FGF-8a, unlike FGF-8b and other members of the family, inhibited osteoclastogenesis in mouse bone marrow cultures, and this was via a receptor activator of NF-κB ligand (RANKL)/osteoprotegerin (OPG)-independendent manner. However, FGF-8a did not affect osteoclastogenesis in RAW 264.7 cells (a macrophage cell line devoid of stromal cells) exogenously stimulated by RANKL, nor did it affect mature osteoclast function as assessed in rat calvarial organ cultures and isolated mature osteoclasts. In summary, we have demonstrated that FGF-8 is active in bone cells, stimulating osteoblast proliferation in a MAPK-independent pathway and inhibiting osteoclastogenesis via a RANKL/OPG-independent mechanism. These data suggest that FGF-8 may have a physiological role in bone acting in an autocrine/paracrine manner.
B-type natriuretic peptide 8-32, which is produced from mature BNP 1-32 by the metalloprotease meprin A, has reduced bioactivity
Authors: Boerrigter Guido , Costello-Boerrigter Lisa C. , Harty Gail J. , Huntley Brenda K. , Cataliotti Alessandro , Lapp Harald , Burnett John C.
Published: April 2009

32-amino acid B-type natriuretic peptide (BNP 1-32) plays an important role in cardiovascular homeostasis. Recently, it was reported that BNP 1-32 is cleaved by the metalloprotease meprin A to BNP 8-32, the bioactivity of which is undefined. We hypothesized that BNP 8-32 has reduced vasodilating and natriuretic bioactivity compared with BNP 1-32 in vivo. Human BNP 8-32 and BNP 1-32 were compared in a crossover study in eight anesthetized normal canines. After a preinfusion clearance, BNP 1-32 was infused at 30 ng·kg−1·min−1 for 45 min followed by a 60-min washout and a second preinfusion clearance. Then, equimolar BNP 8-32 was infused. In half of the studies, the peptide sequence was reversed. Changes with peptides from the respective preinfusion clearance to infusion clearance were compared with paired tests. Mean arterial pressure was reduced by both BNP 8-32 and BNP 1-32 (−8 ± 3 vs. −6 ± 2 mmHg, P = 0.48). Changes in right atrial pressure, pulmonary capillary wedge pressure, heart rate, cardiac output, and glomerular filtration rate were similar. However, urinary sodium excretion increased less with BNP 8-32 than with BNP 1-32 (+171 ± 24 vs. +433 ± 43 μEq/min; P = 0.008), as did urinary potassium excretion, urine flow, and renal blood flow. While BNP 8-32 has similar vasodilating actions as BNP 1-32, its diuretic and natriuretic actions are reduced, suggesting a role for meprin A in the regulation of BNP 1-32 bioactivity in the kidney. Meprin A inhibition may be a potential strategy to increase the bioactivity of endogenous and exogenous BNP 1-32 in cardiovascular diseases.