bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of 3 Spectrophotometric Methods for Carotenoid Determination in Frequently Consumed Fruits and Vegetables
Authors: Biehler Eric , Mayer Frédéric , Hoffmann Lucien , Krause Elmar , Bohn Torsten 
Published: November 2009

ABSTRACT:  Carotenoids are C‐40 tetraterpenoid compounds with potential health beneficial effects. Major dietary sources include a variety of fruits and vegetables. Rapid screening methods are therefore desired, but their accuracy varies depending on the carotenoid profile and the matrix of the plant food. In the present study, 3 different methods were compared, all based on a rapid extraction protocol and spectrophotometric measurements to determine the total amount carotenoids present in fruits and vegetables (n = 28), either with or without chlorophyll. Published methods (a) Lichtenthaler and (b) Hornero‐Méndez and Mínguez‐Mosquera were compared with a newly developed method (method c) based on the average molar absorption coefficient (135310 Lcm−1mol−1) and wavelength (450 nm in acetone), for the 5 predominant carotenoid species (beta‐carotene, zeaxanthin, lycopene, lutein, beta‐cryptoxanthin) in the investigated foods. All results were compared to HPLC (method d). To avoid overestimating carotenoid concentrations due to chlorophyll A and B presence, the effect of saponification was studied for all methods. Overall, saponification led to significant carotenoid losses (12.6 ± 0.9%). Methods a, b, c, and d yielded 5.1 ± 0.4 mg/100 g, 4.6 ± 0.5 mg/100 g, 4.3 ± 0.5 mg/100 g, and 4.2 ± 0.5 mg/100 g total carotenoids, respectively, with method a leading to significant higher mean concentrations compared to all other methods (P < 0.001, Bonferroni) with methods b and c being not significantly different and highly correlated compared to HPLC (> r = 0.95). Similar results were found when stratifying for chlorophyll content and fruits compared with vegetables, however, accuracy varied for individual fruits, highlighting the limitation to use the same method for all plant foods.Practical Application: This study presents a comparison of various rapid spectrophotometric measurements to determine total carotenoid content in various fruits and vegetables and could aid in the selection of the appropriate method for individual plant foods with different carotenoid profile and matrices.
Economic impact of services for first‐episode psychosis: a decision model approach
Authors: McCrone Paul , Knapp Martin , Dhanasiri Sujith 
Published: November 2009

AbstractAim: To assess the impact of early intervention (EI) services on service costs for people with first‐episode psychosis.Methods: A decision model was constructed to map the care pathways following input from EI services and from standard care. A Markov process was used to run the model over 18 2‐month cycles. Probabilities and costs for the model of admissions, readmissions and use of community services were obtained from the literature, routine sources and expert opinion. One‐way and probabilistic sensitivity analyses were conducted to address uncertainty around the parameter estimates.Results: The model estimated 1 year costs to be £9422 for EI and £14 394 for standard care. The respective figures over 3 years were £26 568 and £40 816. One‐way sensitivity analyses revealed that the results were robust to changes in most parameters with the exception of the readmission rate. A relatively small decrease in the readmission rate for standard care patients would eliminate the cost saving. The probabilistic sensitivity analyses also showed that the results were robust to parameter changes.Conclusions: This study suggests cost savings associated with EI. However, caution is required as the model is relatively simple and relies on a number of assumptions.
Transcriptomic Response ofListeria monocytogenesto Iron Limitation andfurMutation
Authors: Ledala Nagender , Sengupta Mrittika , Muthaiyan Arunachalam , Wilkinson Brian J. , Jayaswal R. K. 
Published: November 2009

ABSTRACTIron is required by almost all bacteria, but concentrations above physiological levels are toxic. In bacteria, intracellular iron is regulated mostly by the ferric uptake regulator, Fur, or a similar functional protein. Iron limitation results in the regulation of a number of genes, especially those involved in iron uptake. A subset of these genes is the Fur regulon under the control of Fur. In the present study, we have identified Fur- and iron-regulated genes inListeria monocytogenesby DNA microarray analysis using afurmutant and its isogenic parent. To identify genes regulated exclusively in response to iron limitation, the whole-genome transcriptional responses to the iron limitation of afurmutant and its isogenic parent were compared. Fur-regulated genes were identified by comparing the transcriptional profile of the parent with the transcriptional profile of the isogenicfurmutant. Our studies have identified genes regulated exclusively in response to iron and those that are negatively regulated by Fur. We have identified at least 14 genes that were negatively regulated directly by Fur. Under iron-limited conditions, these genes were upregulated, while the expression offurwas found to be downregulated. To further investigate the regulation offurin response to iron, an ectopicfurpromoter-lacZtranscriptional fusion strain was constructed, and its isogenicfurandperRmutant derivatives were generated inL. monocytogenes10403S. Analysis of the iron limitation of theperRmutant indicated that the regulation of genes under the negative control of Fur was significantly inhibited. Our results indicate that Fur and PerR proteins negatively regulatefurand that under iron-limited conditions, PerR is required for the negative regulation of genes controlled by Fur.
Improved Risk Analysis by Dual Direct Detection of Total and Infectious
Cryptosporidium
Oocysts on Cell Culture in Combination with Immunofluorescence Assay
Authors: Lalancette Cindy , Di Giovanni George D. , Prévost Michèle 
Published: November 2009

ABSTRACT

The inactivation of
Cryptosporidium
oocysts is a main driver in the selection of water treatment disinfection strategies, and microbial risk analysis provides a sound basis for optimizing water treatment processes. U.S. Environmental Protection Agency method 1622/23 provides an estimate of the total oocyst count; however, it cannot be used directly for risk assessment, as it does not determine the fraction of infectious oocysts. Improved assessment of the risk for designated sources or in treated water requires evaluation of the total number of oocysts and an estimate of their infectivity. We developed a dual direct detection method using differential immunofluorescent staining that allows detection of both oocysts and cell culture infection foci for each sample. Using
Cryptosporidium parvum
oocysts, various pH levels, proteases, and gastroenteric compounds and substrates were assessed to determine their abilities to enhance the number of infection foci. The results showed that the key trigger for oocyst stimulation was acidification. Addition of a low concentration of
d
-glucose (50 mM) to the infection media increased rates of infectivity, while a higher dose (300 mM) was inhibitory. The total number of oocysts in each sample was determined by counting the oocysts remaining on a cell monolayer and the oocysts recovered from cell monolayer washes during processing using a simple filtration technique. With the dual direct detection on cell culture with immunofluorescence assay method, it is now possible to determine the numbers of total and infectious oocysts for a given sample in a single analysis. Direct percentages of infectivity are then calculated, which allows more accurate assessments of risk.
Cotranslocation of Methyl Parathion Hydrolase to the Periplasm and of Organophosphorus Hydrolase to the Cell Surface of
Escherichia coli
by the Tat Pathway and Ice Nucleation Protein Display System
Authors: Yang Chao , Freudl Roland , Qiao Chuanling , Mulchandani Ashok 
Published: November 2009

ABSTRACT

A genetically engineered
Escherichia coli
strain coexpressing organophosphorus hydrolase (OPH) and methyl parathion hydrolase (MPH) was constructed for the first time by cotransforming two compatible plasmids. Since these two enzymes have different substrate specificities, the coexpression strain showed a broader substrate range than strains expressing either one of the hydrolases. To reduce the mass transport limitation of organophosphates (OPs) across the cell membrane, MPH and OPH were simultaneously translocated to the periplasm and cell surface of
E. coli
, respectively, by employing the twin-arginine translocation (Tat) pathway and ice nucleation protein (INP) display system. The resulting recombinant strain showed sixfold-higher whole-cell activity than the control strain expressing cytosolic OP hydrolases. The correct localization of MPH and OPH was demonstrated by cell fractionation, immunoblotting, and enzyme activity assays. No growth inhibition was observed for the recombinant
E. coli
strain, and suspended cultures retained almost 100% of the activity over a period of 2 weeks. Owing to its high level of activity and superior stability, the recombinant
E. coli
strain could be employed as a whole-cell biocatalyst for detoxification of OPs. This strategy of utilizing dual translocation pathways should open up new avenues for cotranslocating multiple functional moieties to different extracytosolic compartments of a bacterial cell.
Iron Sources Used by the Nonpathogenic Lactic Acid Bacterium
Lactobacillus sakei
as Revealed by Electron Energy Loss Spectroscopy and Secondary-Ion Mass Spectrometry
Authors: Duhutrel Philippe , Bordat Christian , Wu Ting-Di , Zagorec Monique , Guerquin-Kern Jean-Luc , Champomier-Vergès Marie-Christine 
Published: November 2009

ABSTRACT

Lactobacillus sakei
is a lactic acid bacterium naturally found on meat. Although it is generally acknowledged that lactic acid bacteria are rare species in the microbial world which do not have iron requirements, the genome sequence of
L. sakei
23K has revealed quite complete genetic equipment dedicated to transport and use of this metal. Here, we aimed to investigate which iron sources could be used by this species as well as their role in the bacterium's physiology. Therefore, we developed a microscopy approach based on electron energy loss spectroscopy (EELS) analysis and nano-scale secondary-ion mass spectrometry (SIMS) in order to analyze the iron content of
L. sakei
cells. This revealed that
L. sakei
can use iron sources found in its natural ecosystem, myoglobin, hemoglobin, hematin, and transferrin, to ensure long-term survival during stationary phase. This study reveals that analytical image methods (EELS and SIMS) are powerful complementary tools for investigation of metal utilization by bacteria.
Analysis of Lipid Export in Hydrocarbonoclastic Bacteria of the GenusAlcanivorax: Identification of Lipid Export-Negative Mutants ofAlcanivorax borkumensisSK2 andAlcanivorax jadensisT9
Authors: Manilla-Pérez Efraín , Reers Christina , Baumgart Meike , Hetzler Stephan , Reichelt Rudolf , Malkus Ursula , Kalscheuer Rainer , Wältermann Marc , Steinbüchel Alexander 
Published: November 2009

ABSTRACTTriacylglycerols (TAGs), wax esters (WEs), and polyhydroxyalkanoates (PHAs) are the major hydrophobic compounds synthesized in bacteria and deposited as cytoplasmic inclusion bodies when cells are cultivated under imbalanced growth conditions. The intracellular occurrence of these compounds causes high costs for downstream processing.Alcanivoraxspecies are able to produce extracellular lipids when the cells are cultivated on hexadecane or pyruvate as the sole carbon source. In this study, we developed a screening procedure to isolate lipid export-negative transposon-induced mutants of bacteria of the genusAlcanivoraxfor identification of genes required for lipid export by employing the dyes Nile red and Solvent Blue 38. Three transposon-induced mutants ofA. jadensisand seven ofA. borkumensisimpaired in lipid secretion were isolated. All isolated mutants were still capable of synthesizing and accumulating these lipids intracellularly and exhibited no growth defect. In theA. jadensismutants, the transposon insertions were mapped in genes annotated as encoding a putative DNA repair system specific for alkylated DNA (Aj17), a magnesium transporter (Aj7), and a transposase (Aj5). In theA. borkumensismutants, the insertions were mapped in genes encoding different proteins involved in various transport processes, like genes encoding (i) a heavy metal resistance (CZCA2) in mutant ABO_6/39, (ii) a multidrug efflux (MATE efflux) protein in mutant ABO_25/21, (iii) an alginate lyase (AlgL) in mutants ABO_10/30 and ABO_19/48, (iv) a sodium-dicarboxylate symporter family protein (GltP) in mutant ABO_27/29, (v) an alginate transporter (AlgE) in mutant ABO_26/1, or (vi) a two-component system protein in mutant ABO_27/56. Site-directedMATE,algE, andalgLgene disruption mutants, which were constructed in addition, were also unable to export neutral lipids and confirmed the phenotype of the transposon-induced mutants. The putative localization of the different gene products and their possible roles in lipid excretion are discussed. Beside this, the composition of the intra- and extracellular lipids in the wild types and mutants were analyzed in detail.
Thioredoxin System from
Deinococcus radiodurans
Authors: Obiero Josiah , Pittet Vanessa , Bonderoff Sara A. , Sanders David A. R. 
Published: November 2009

ABSTRACT

This paper describes the cloning, purification, and characterization of thioredoxin (Trx) and thioredoxin reductase (TrxR) and the structure determination of TrxR from the ionizing radiation-tolerant bacterium
Deinococcus radiodurans
strain R1. The genes from
D. radiodurans
encoding Trx and TrxR were amplified by PCR, inserted into a pET expression vector, and overexpressed in
Escherichia coli.
The overexpressed proteins were purified by metal affinity chromatography, and their activity was demonstrated using well-established assays of insulin precipitation (for Trx), 5,5′-dithiobis(2-nitrobenzoic acid) (DTNB) reduction, and insulin reduction (for TrxR). In addition, the crystal structure of oxidized TrxR was determined at 1.9-Å resolution. The overall structure was found to be very similar to that of
E. coli
TrxR and homodimeric with both NADPH- and flavin adenine dinucleotide (FAD)-binding domains containing variants of the canonical nucleotide binding fold, the Rossmann fold. The

K
m

(5.7 μM) of
D. radiodurans
TrxR for
D. radiodurans
Trx was determined and is about twofold higher than that of the
E. coli
thioredoxin system. However,
D. radiodurans
TrxR has a much lower affinity for
E. coli
Trx (

K
m

, 44.4 μM). Subtle differences in the surface charge and shape of the Trx binding site on TrxR may account for the differences in recognition. Because it has been suggested that TrxR from
D. radiodurans
may have dual cofactor specificity (can utilize both NADH and NADPH),
D. radiodurans
TrxR was tested for its ability to utilize NADH as well. Our results show that
D. radiodurans
TrxR can utilize only NADPH for activity.
GyrA Interacts with MarR To Reduce Repression of themarRABOperon inEscherichia coli
Authors: Domain Francis , Levy Stuart B. 
Published: November 2009

ABSTRACTBacterial two-hybrid studies of randomly clonedEscherichia coliDNA identified a physical interaction between GyrA, subunit A of gyrase, and MarR, a repressor of themarRABoperon. GyrA-His immobilized on Ni-nitrilotriacetic acid (NiNTA) resin bound MarR, while MarR alone did not bind. GyrA interfered with MarR binding tomarO, as detected by electrophoretic mobility assays. In a strain bearing themarRABoperon and amarO-lacZreporter, overexpression of GyrA increased LacZ activity, indicating decreased repression ofmarO-lacZby MarR. These results were confirmed by an increased survival of cells treated with quinolones and other antibiotics when GyrA was overexpressed. This work, like a previous study examining TktA (12), shows that unrelated proteins can regulate MarR activity. The findings reveal an unexpected regulatory function of GyrA in antibiotic resistance.
Genetic Variants of Human Parvovirus B19 in South Africa: Cocirculation of Three Genotypes and Identification of a Novel Subtype of Genotype 1
Authors: Corcoran Craig , Hardie Diana , Yeats Jane , Smuts Heidi 
Published: November 2009

ABSTRACT
Parvovirus B19 comprises three distinct genotypes (1, 2, and 3). The distribution of B19 genotypes has not before been examined in South Africa. Two hundred thirty-nine laboratory samples submitted to a diagnostic virology laboratory for parvovirus DNA detection were analyzed retrospectively. Of the 53 PCR-positive samples investigated, 40 (75.4%) were identified as genotype 1 by genotype-specific PCR or consensus NS1 PCR and sequencing and 3 (5.7%) as genotype 2 and 10 (18.9%) as genotype 3 by analysis of NS1 sequences. Furthermore, phylogenetic analysis identified two genotype 1 sequences which were distinct from the previously described genotypes 1A and 1B. Interestingly, a genotype 2 virus was detected in the serum of an 11-year-old child, providing evidence for its recent circulation. This is the first study to demonstrate the concurrent circulation of all three genotypes of B19 in South Africa and the provisional identification of a novel subtype of genotype 1. The implications of parvovirus B19 variation are discussed.
First Report of
Gordonibacter pamelaeae
Bacteremia
Authors: Woo Patrick C. Y. , Teng Jade L. L. , Lam Kay K. M. , Tse Cindy W. S. , Leung Kit-Wah , Leung Anthony W. S. , Lau Susanna K. P. , Yuen Kwok-Yung 
Published: November 2009

ABSTRACT

We report the first case of
Gordonibacter pamelaeae
bacteremia, identified by phenotypic tests and 16S rRNA sequencing in a patient with disseminated rectosigmoid carcinoma and responsive to amoxicillin-clavulanate. The bacterium was a nonsporulating, anaerobic, Gram-positive, nonmotile, coccobacillus that was catalase, arginine dihydrolase, and arginine acrylamidase positive. The gastrointestinal tract is probably its reservoir.
Transmission of Methicillin-Resistant
Staphylococcus aureus
to Household Contacts
Authors: Mollema F. P. N. , Richardus J. H. , Behrendt M. , Vaessen N. , Lodder W. , Hendriks W. , Verbrugh H. A. , Vos M. C. 
Published: November 2009

ABSTRACT

The frequency of and risk factors for methicillin-resistant
Staphylococcus aureus
(MRSA) transmission from a MRSA index person to household contacts were assessed in this prospective study. Between January 2005 and December 2007, 62 newly diagnosed MRSA index persons (46 patients and 16 health care workers) and their 160 household contacts were included in the study analysis. Transmission of MRSA from an index person to household contacts occurred in nearly half of the cases (47%;
n
= 29). These 29 index persons together had 84 household contacts, of which two-thirds (67%;
n
= 56) became MRSA positive. Prolonged exposure time to MRSA at home was a significant risk factor for MRSA transmission to household contacts. In addition, MRSA colonization at least in the throat, younger age, and eczema in index persons were significantly associated with MRSA transmission; the presence of wounds was negatively associated with MRSA transmission. Furthermore, an increased number of household contacts and being the partner of a MRSA index person were household-related risk factors for MRSA acquisition from the index person. No predominant pulsed-field gel electrophoresis (PFGE) type was observed to be transmitted more frequently than other PFGE types. To date, screening household contacts and providing MRSA eradication therapy to those found positive simultaneously with the index person is not included in the “search-and-destroy” policy. We suggest including both in MRSA prevention guidelines, as this may reduce further spread of MRSA.
Theiler's Murine Encephalomyelitis Virus L* Amino Acid Position 93 Is Important for Virus Persistence and Virus-Induced Demyelination
Authors: Stavrou Spyridon , Baida Gleb , Viktorova Ekaterina , Ghadge Ghanashyam , Agol Vadim I. , Roos Raymond P. 
Published: November 2009

ABSTRACT
The DA strain and other members of the TO subgroup of Theiler's murine encephalomyelitis virus (TMEV) induce a persistent central nervous system infection associated with an inflammatory white matter demyelinating disease. TO subgroup strains synthesize an 18-kDa protein, L*, out of frame with the polyprotein from an initiation codon 13 nucleotides downstream from the polyprotein's AUG codon. We previously generated a mutant virus from our infectious DA full-length clone that has a change of the L* AUG codon to ACG (with no change in the polyprotein's amino acid sequence). Studies of this mutant virus showed that L* was key to the TO subgroup phenotype because the mutant had a decreased ability to persist and demyelinate. This work was initially called into question because a similar mutant derived from a different full-length DA infectious clone persisted and demyelinated similarly to wild-type DA virus (O. van Eyll and T. Michiels, J. Virol. 74:9071-9077, 2000). We now report that (i) the sequence of the L* coding region differs in the two infectious clones, resulting in a Ser or Leu as the predicted amino acid at position 93 of L* (with no change in the polyprotein's amino acid sequence), (ii) the difference in this amino acid is key to the phenotypic differences between the two mutants, and (iii) the change in amino acid 93 may affect L* phosphorylation. It is of interest that this amino acid only appears critical in determining the virus phenotype when L* is present in a significantly reduced amount (i.e., following translation from an ACG initiating codon).
Multimerization of Hepatitis Delta Antigen Is a Critical Determinant of RNA Binding Specificity
Authors: Lin Brian C. , Defenbaugh Dawn A. , Casey John L. 
Published: November 2009

ABSTRACT
Hepatitis delta virus (HDV) RNA forms an unbranched rod structure that is associated with hepatitis delta antigen (HDAg) in cells replicating HDV. Previous in vitro binding experiments using bacterially expressed HDAg showed that the formation of a minimal ribonucleoprotein complex requires an HDV unbranched rod RNA of at least about 300 nucleotides (nt) and suggested that HDAg binds the RNA as a multimer of fixed size. The present study specifically examines the role of HDAg multimerization in the formation of the HDV ribonucleoprotein complex (RNP). Disruption of HDAg multimerization by site-directed mutagenesis was found to profoundly alter the nature of RNP formation. Mutant HDAg proteins defective for multimerization exhibited neither the 300-nt RNA size requirement for binding nor specificity for the unbranched rod structure. The results unambiguously demonstrate that HDAg binds HDV RNA as a multimer and that the HDAg multimer is formed prior to binding the RNA. RNP formation was found to be temperature dependent, which is consistent with conformational changes occurring on binding. Finally, analysis of RNPs constructed with unbranched rod RNAs successively longer than the minimum length indicated that multimeric binding is not limited to the first HDAg bound and that a minimum RNA length of between 604 and 714 nt is required for binding of a second multimer. The results confirm the previous proposal that HDAg binds as a large multimer and demonstrate that the multimer is a critical determinant of the structure of the HDV RNP.