bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fucose‐deficient hematopoietic stem cells have decreased self‐renewal and aberrant marrow niche occupancy
Authors: Myers Jay , Huang Yuanshuai , Wei Lebing , Yan Quanjian , Huang Alex , Zhou Lan 
Published: June 2010

BACKGROUND: Modification of Notch receptors by O‐linked fucose and its further elongation by the Fringe family of glycosyltransferase has been shown to be important for Notch signaling activation. Our recent studies disclose a myeloproliferative phenotype, hematopoietic stem cell (HSC) dysfunction, and abnormal Notch signaling in mice deficient in FX, which is required for fucosylation of a number of proteins including Notch. The purpose of this study was to assess the self‐renewal and stem cell niche features of fucose‐deficient HSCs.STUDY DESIGN AND METHODS: Homeostasis and maintenance of HSCs derived from FX−/− mice were studied by serial bone marrow transplantation, homing assay, and cell cycle analysis. Two‐photon intravital microscopy was performed to visualize and compare the in vivo marrow niche occupancy by fucose‐deficient and wild‐type (WT) HSCs.RESULTS: Marrow progenitors from FX−/− mice had mild homing defects that could be partially prevented by exogenous fucose supplementation. Fucose‐deficient HSCs from FX−/− mice displayed decreased self‐renewal capability compared with the WT controls. This is accompanied with their increased cell cycling activity and suppressed Notch ligand binding. When tracked in vivo by two‐photon intravital imaging, the fucose‐deficient HSCs were found localized farther from the endosteum of the calvarium marrow than the WT HSCs.CONCLUSIONS: The current reported aberrant niche occupancy by HSCs from FX−/− mice, in the context of a faulty blood lineage homeostasis and HSC dysfunction in mice expressing Notch receptors deficient in O‐fucosylation, suggests that fucosylation‐modified Notch receptor may represent a novel extrinsic regulator for HSC engraftment and HSC niche maintenance.
Negative delayed‐enhancement magnetic resonance imaging of the heart suggests a diagnosis of neonatal transient myocardial ischaemia
Authors: Brouwers Arno GA , Van Elburg Ruurd M , Beek Aernout M , Rammeloo Lukas AJ 
Published: June 2010

AbstractWe report a term neonate presenting after birth with shock and cyanosis for which he was intubated. Echocardiography showed no contractions of the left ventricle. Systemic circulation was provided by the right ventricle via shunting through the arterial duct. Left ventricular dysfunction was confirmed by electrocardiography and increased troponin T levels. Hemodynamics quickly improved, and the child could be weaned of the ventilator without residual problems. We concluded that the patient suffered from transient myocardial ischaemia. At 3 weeks of life, we performed delayed‐enhancement magnetic resonance imaging (DE‐MRI) of the heart which did not show signs of permanent macroscopic damage of the myocardium.Conclusion:  This is the first reported case report on the use of DE‐MRI in a neonate with transient myocardial ischaemia. DE‐MRI may provide information that helps to predict recovery in the acute stage of left ventricular dysfunction or at a later stage when absence of recovery of left ventricular function needs to be explained.
Class II DRB polymorphism and sequence diversity in two vesper bats in the genus Myotis
Authors: Richman A. D. , Herrera M. L. G. , Ortega‐García S. , Flores‐Martínez J. J. , Arroyo‐Cabrales J. , Morales‐Malacara J. B. 
Published: June 2010

SummaryAlmost no studies have been done with respect to major histocompatibility complex (MHC) polymorphism and sequence diversity in bats, although they account for one in five living mammalian species. We analysed MHC Class II DRB polymorphism and sequence diversity in two Mexican verpertilionid bat species, the widespread continental species Myotis velifer and the narrowly distributed (and endangered) island endemic Myotis vivesi. We find extensive DRB polymorphism in the widespread M. velifer, similar to that commonly reported in other mammals. The geographically restricted M. vivesi by contrast shows only very limited polymorphism. We conclude that M. vivesi has undergone a dramatic loss of MHC polymorphism. The significance of this inference in light of other information on population structure and genetic diversity in this species is discussed.
Inter‐laboratory comparison of radiometric culture forMycobacterium aviumsubsp.paratuberculosisusing raw milk from known infected herds and individual dairy cattle in Victoria
Authors: Ridge SE , Andreata S , Jones K , Cantlon K , Francis B , Florisson N , Gwozdz J 
Published: June 2010

Objective To compare the results of radiometric culture conducted in three Australian laboratories forMycobacterium aviumsubsp.paratuberculosis(Mptb) using bulk vat and individual animal milk samples.Procedure Milk samples were collected from 15 cows exhibiting clinical signs of Johne's disease, and subsequently confirmed as infected with Mptb, and from the bulk milk vats on 91 farms running herds known to be infected with Mptb. Each milk sample was divided into three equivalent samples and one of each of the replicates was forwarded to the three participating laboratories. The identity and nature of the samples was protected from the study collaborators. The laboratories processed the samples and undertook radiometric culture for Mptb using their standard method. Results of testing were provided to the principal investigator for collation and analysis.Results In total, 2 (2.2%) of 91 vat‐milk samples and 8 (53.3%) of 15 individual cows' milk samples returned positive radiometric milk culture results. Only one sample, from a clinical case of Johne's disease, was identified as positive by more than one laboratory. There were differences in the absolute frequency with which Mptb was identified in the milk samples by the collaborating laboratories.Conclusions Mptb was cultured from a very small percentage of Australian raw bulk milk samples sourced from known infected herds. By contrast, Mptb was successfully cultured from half of the milk samples collected from clinically affected cows. There was no statistical difference between laboratories in the proportion of vat samples or individual animal milk samples in which Mptb was detected.
Spore Film Dosimeters Are Feasible for UV Dose Monitoring During Heliotherapy
Authors: Vähävihu Katja , Ylianttila Lasse , Kautiainen Hannu , Tuohimaa Pentti , Reunala Timo , Snellman Erna 
Published: June 2010

AbstractThe objective of the study was to compare Bacillus subtilis spore film dosimeters with a Robertson Berger UV meter (RB meter) and diary records for assessing personal UV‐B doses during a 13‐day heliotherapy (HT) for atopic dermatitis (AD). In addition, the relationship between the personal UV‐B dose and change in serum 25‐hydroxyvitamin D (25(OH)D) was studied. Altogether 21 adult patients with AD completed the study arranged in the Canary Islands, either in January or March 2005. The spore film dosimeters were used throughout the day during the HT. Serum 25(OH)D was analyzed using radioimmunoassay. The mean personal UV‐B dose measured with the dosimeters was 75 SED in January and 131 SED in March. The respective results gained from the RB meter combined with diary records were 63 SED and 119 SED showing a close correlation with the dosimeter results. Serum 25(OH)D concentration increased by 9.7 nmol L−1 in January and by 26.0 7 nmol L−1 in March. The increase in serum 25(OH)D correlated with the UV‐B dose received. The patients complied well to use the dosimeters. We conclude spore films to be a feasible and reliable personal UV dosimeter in vivo in field conditions.
The Hydroxypyridinone Iron Chelator CP94 Can Enhance PpIX‐induced PDT of Cultured Human Glioma Cells
Authors: Blake Emma , Curnow Alison 
Published: June 2010

AbstractPhotodynamic therapy (PDT) with the pro‐drugs 5‐aminolevulinic acid (ALA) or methyl aminolevulinate (MAL) utilizes the combined interaction of a photosensitizer, light and molecular oxygen to ablate tumor tissue. To potentially increase accumulation of the photosensitizer, protoporphyrin IX (PpIX), within tumor cells an iron chelator can be employed. This study analyzed the effects of ALA/MAL‐induced PDT combined with the iron chelator 1, 2‐diethyl‐3‐hydroxypyridin‐4‐one hydrochloride (CP94) on the accumulation of PpIX in human glioma cells in vitro. Cells were incubated for 0, 3 and 6 h with various concentrations of ALA/MAL with or without CP94 and the resulting accumulations of PpIX, which naturally fluoresces, were quantified prior to and following light irradiation. In addition, counts of viable cells were recorded. The use of CP94 in combination with ALA/MAL produced significant enhancements of PpIX fluorescence in human glioma cells. At the highest concentrations of each prodrug, CP94 enhanced PpIX fluorescence significantly at 3 h for ALA and by more than 50% at 6 h for MAL. Cells subsequently treated with ALA/MAL‐induced PDT in combination with CP94 produced the greatest cytotoxicity. It is therefore concluded that with further study CP94 may be a useful adjuvant to photodiagnosis and/or PpIX‐induced PDT treatment of glioma.
Mining bacterial genomes for novel arylesterase activity
Authors: Wang Lijun , Mavisakalyan Valentina , Tillier Elisabeth R. M. , Clark Greg W. , Savchenko Alexei V. , Yakunin Alexander F. , Master Emma R. 
Published: June 2010

SummaryOne hundred and seventy‐one genes encoding potential esterases from 11 bacterial genomes were cloned and overexpressed in Escherichia coli; 74 of the clones produced soluble proteins. All 74 soluble proteins were purified and screened for esterase activity; 36 proteins showed carboxyl esterase activity on short‐chain esters, 17 demonstrated arylesterase activity, while 38 proteins did not exhibit any activity towards the test substrates. Esterases from Rhodopseudomonas palustris (RpEST‐1, RpEST‐2 and RpEST‐3), Pseudomonas putida (PpEST‐1, PpEST‐2 and PpEST‐3), Pseudomonas aeruginosa (PaEST‐1) and Streptomyces avermitilis (SavEST‐1) were selected for detailed biochemical characterization. All of the enzymes showed optimal activity at neutral or alkaline pH, and the half‐life of each enzyme at 50°C ranged from < 5 min to over 5 h. PpEST‐3, RpEST‐1 and RpEST‐2 demonstrated the highest specific activity with pNP‐esters; these enzymes were also among the most stable at 50°C and in the presence of detergents, polar and non‐polar organic solvents, and imidazolium ionic liquids. Accordingly, these enzymes are particularly interesting targets for subsequent application trials. Finally, biochemical and bioinformatic analyses were compared to reveal sequence features that could be correlated to enzymes with arylesterase activity, facilitating subsequent searches for new esterases in microbial genome sequences.
Exacerbation of adult‐onset Still’s disease, possibly related to elevation of serum tumor necrosis factor‐alpha after etanercept administration
Authors: KANEKO Kaichi , KABURAKI Makoto , MURAOKA Sei , TANAKA Nahoko , YAMAMOTO Tatsuhiro , KUSUNOKI Yoshie , ABE Haruo , ENDO Hirahito , KAWAI Shinichi 
Published: June 2010

AbstractAdult‐onset Still’s disease (AOSD) is a systemic inflammatory disease of unknown etiology. A 44‐year‐old male patient presented with AOSD complicated by macrophage activation syndrome after etanercept therapy. His serum tumor necrosis factor‐α (TNF‐α) level was increased dramatically after etanercept therapy. The clinical course of this case suggests that the increased TNF‐α level by etanercept administration might cause macrophage activation syndrome in this case.
Detection of Microcystin-Producing Cyanobacteria in Missisquoi Bay, Quebec, Canada, Using Quantitative PCR
Authors: Fortin Nathalie , Aranda-Rodriguez Rocio , Jing Hongmei , Pick Frances , Bird David , Greer Charles W. 
Published: June 2010

ABSTRACT

Toxic cyanobacterial blooms, as well as their increasing global occurrence, pose a serious threat to public health, domestic animals, and livestock. In Missisquoi Bay, Lake Champlain, public health advisories have been issued from 2001 to 2009, and local microcystin concentrations found in the lake water regularly exceeded the Canadian drinking water guideline of 1.5 μg liter
−1
. A quantitative PCR (Q-PCR) approach was developed for the detection of blooms formed by microcystin-producing cyanobacteria. Primers were designed for the β-ketoacyl synthase (
mcyD
KS
) and the first dehydratase domain (
mcyD
DH
) of the
mcyD
gene, involved in microcystin synthesis. The Q-PCR method was used to track the toxigenic cyanobacteria in Missisquoi Bay during the summers of 2006 and 2007. Two toxic bloom events were detected in 2006: more than 6.5 × 10
4
copies of the
mcyD
KS
gene ml
−1
were detected in August, and an average of 4.0 × 10
4
copies ml
−1
were detected in September, when microcystin concentrations were more than 4 μg liter
−1
and approximately 2 μg liter
−1
, respectively. Gene copy numbers and total microcystin concentrations (determined by enzyme-linked immunosorbent assay [ELISA]) were highly correlated in the littoral (
r
= 0.93,
P
< 0.001) and the pelagic station (
r
= 0.87,
P
< 0.001) in 2006. In contrast to the situation in 2006, a cyanobacterial bloom occurred only in late summer-early fall of 2007, reaching only 3 × 10
2
mcyD
KS
copies ml
−1
, while the microcystin concentration was barely detectable. The Q-PCR method allowed the detection of microcystin-producing cyanobacteria when toxins and toxigenic cyanobacterial abundance were still below the limit of detection by high-pressure liquid chromatography (HPLC) and microscopy. Toxin gene copy numbers grew exponentially at a steady rate over a period of 7 weeks. Onshore winds selected for cells with a higher cell quota of microcystin. This technique could be an effective approach for the routine monitoring of the most at-risk water bodies.
Requirement of Purine and Pyrimidine Synthesis for Colonization of the Mouse Intestine by
Escherichia coli
Authors: Vogel-Scheel Jacqueline , Alpert Carl , Engst Wolfram , Loh Gunnar , Blaut Michael 
Published: June 2010

ABSTRACT

To study the adaptation of an intestinal bacterium to its natural environment, germfree mice were associated with commensal
Escherichia coli
MG1655. Two-dimensional gel electrophoresis was used to identify proteins differentially expressed in
E. coli
MG1655 collected from either cecal contents or anaerobic
in vitro
cultures. Fourteen differentially expressed proteins (>3-fold;
P
< 0.05) were identified, nine of which were upregulated in cecal versus
in vitro
-grown
E. coli
. Four of these proteins were investigated further for their role in gut colonization. After deletion of the corresponding genes, the resulting
E. coli
mutants were tested for their ability to colonize the intestines of gnotobiotic mice in competition with the wild-type strain. A mutant devoid of
ydjG
, which encodes a putative NADH-dependent methylglyoxal reductase, reached a 1.2-log-lower cecal concentration than the wild type. Deletion of the
nanA
gene encoding
N
-acetylneuraminate lyase affected the colonization and persistence of
E. coli
in the intestines of the gnotobiotic mice only slightly. A mutant devoid of 5′-phosphoribosyl 4-(
N
-succinocarboxamide)-5-aminoimidazole synthase, a key enzyme of purine synthesis, displayed intestinal cell counts >4 logs lower than those of the wild type. Deletion of the gene encoding aspartate carbamoyltransferase, a key enzyme of pyrimidine synthesis, even resulted in the washout of the corresponding mutant from the mouse intestinal tract. These findings indicate that
E. coli
needs to synthesize purines and pyrimidines to successfully colonize the mouse intestine.
Direct Observation and Analysis of Bacterial Growth on an Antimicrobial Surface
Authors: Yamada Hiroyuki , Takahashi Nobuyuki , Okuda Shujiro , Tsuchiya Yuki , Morisaki Hisao 
Published: June 2010

ABSTRACT

Cells of
Escherichia coli
NBRC 3972 and
Staphylococcus aureus
NBRC 12732 were inoculated onto an agar (1.5%) medium varying in nutrient concentration from full strength of the nutrient broth (NB) to 1/10 NB. Immediately thereafter, the inoculated agar was placed on antimicrobial and nonantimicrobial surfaces in such a way that the microbial cells came into contact with these surfaces. Cell growth was directly observed under a microscope, and the growth rate constant of the cells was measured based on the increase in the area of the colonies formed by the growing cells. On the antimicrobial surface, the growth rate constant decreased at lower nutrient concentrations for both
E. coli
and
S. aureus
cells, whereas it showed little change on the nonantimicrobial surface. It was supposed that either the nutrient uptake or the nutrient utilization efficiency was retarded by the antimicrobial surface. At the lowest nutrient concentration examined in the present study, 1/10 NB, the cells could hardly grow on the antimicrobial surface, indicating that the surface would be sufficiently active in preventing bacterial growth under normal usage conditions, such as the wet areas of a kitchen. It was also revealed that the antimicrobial surface could prevent the division of cells either during the growth stage or before the onset of growth.
Ammonium Concentrations in Produced Waters from a Mesothermic Oil Field Subjected to Nitrate Injection Decrease through Formation of Denitrifying Biomass and Anammox Activity
Authors: Cornish Shartau Sabrina L. , Yurkiw Marcy , Lin Shiping , Grigoryan Aleksandr A. , Lambo Adewale , Park Hyung-Soo , Lomans Bart P. , van der Biezen Erwin , Jetten Mike S. M. , Voordouw Gerrit 
Published: June 2010

ABSTRACT

Community analysis of a mesothermic oil field, subjected to continuous field-wide injection of nitrate to remove sulfide, with denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S rRNA genes indicated the presence of heterotrophic and sulfide-oxidizing, nitrate-reducing bacteria (hNRB and soNRB). These reduce nitrate by dissimilatory nitrate reduction to ammonium (e.g.,
Sulfurospirillum
and
Denitrovibrio
) or by denitrification (e.g.,
Sulfurimonas
,
Arcobacter
, and
Thauera
). Monitoring of ammonium concentrations in producing wells (PWs) indicated that denitrification was the main pathway for nitrate reduction in the field: breakthrough of nitrate and nitrite in two PWs was not associated with an increase in the ammonium concentration, and no increase in the ammonium concentration was seen in any of 11 producing wells during periods of increased nitrate injection. Instead, ammonium concentrations in produced waters decreased on average from 0.3 to 0.2 mM during 2 years of nitrate injection. Physiological studies with produced water-derived hNRB microcosms indicated increased biomass formation associated with denitrification as a possible cause for decreasing ammonium concentrations. Use of anammox-specific primers and cloning of the resulting PCR product gave clones affiliated with the known anammox genera “
Candidatus
Brocadia” and “
Candidatus
Kuenenia,” indicating that the anammox reaction may also contribute to declining ammonium concentrations. Overall, the results indicate the following: (i) that nitrate injected into an oil field to oxidize sulfide is primarily reduced by denitrifying bacteria, of which many genera have been identified by DGGE, and (ii) that perhaps counterintuitively, nitrate injection leads to decreasing ammonium concentrations in produced waters.
Differential Regulation of Six Heavy Metal Efflux Systems in the Response of
Myxococcus xanthus
to Copper
Authors: Moraleda-Muñoz Aurelio , Pérez Juana , Extremera Antonio Luis , Muñoz-Dorado José 
Published: June 2010

ABSTRACT

Myxococcus xanthus
has to cope with changes in its environment during growth and development. Among these factors, the concentration of copper is crucial due to the essential toxic effect of this metal, which forces the cells to maintain a tight homeostasis. The
M. xanthus
copper response is more complex than that in other bacteria, which is reflected by the different copper sensitivities of growing and developing cells. In the present study, the participation in copper homeostasis of six heavy metal efflux systems encoded in the
M. xanthus
genome has been examined. Three of these pumps exhibit the signature sequences in transmembrane domain 4 of the Cus systems (Cus1, Cus2, and Cus3), while the other three exhibit the motifs of the Czc systems (Czc1, Czc2, and Czc3). The Cus2 and Cus3 systems are inducible by copper and monovalent metals, functioning as the main copper efflux pumps, while the Cus1 system is implicated in Zn
2+
homeostasis. The Czc systems are also differentially regulated either by divalent metals but not by copper (Czc1), by copper and divalent metals (Czc2), or by starvation (Czc3). The differential regulation of these six efflux systems ensures the proper completion of the
M. xanthus
life cycle in an environment with fluctuating concentrations of copper and other metals.
Identification and Elimination of the Competing
N
-Acetyldiaminopentane Pathway for Improved Production of Diaminopentane by
Corynebacterium glutamicum
Authors: Kind Stefanie , Jeong Weol Kyu , Schröder Hartwig , Zelder Oskar , Wittmann Christoph 
Published: June 2010

ABSTRACT

The present work describes the development of a superior strain of
Corynebacterium glutamicum
for diaminopentane (cadaverine) production aimed at the identification and deletion of the underlying unknown
N
-acetyldiaminopentane pathway. This acetylated product variant, recently discovered, is a highly undesired by-product with respect to carbon yield and product purity. Initial studies with
C. glutamicum
DAP-3c, a previously derived tailor-made diaminopentane producer, showed that up to 20% of the product occurs in the unfavorable acetylated form. The strain revealed enzymatic activity for diaminopentane acetylation, requiring acetyl-coenzyme A (CoA) as a donor. Comparative transcriptome analysis of DAP-3c and its parent strain did not reveal significant differences in the expression levels of 17 potential candidates annotated as
N
-acetyltransferases. Targeted single deletion of several of the candidate genes showed NCgl1469 to be the responsible enzyme. NCgl1469 was functionally assigned as diaminopentane acetyltransferase. The deletion strain, designated
C. glutamicum
DAP-4, exhibited a complete lack of
N
-acetyldiaminopentane accumulation in medium. Hereby, the yield for diaminopentane increased by 11%. The mutant strain allowed the production of diaminopentane as the sole product. The deletion did not cause any negative growth effects, since the specific growth rate and glucose uptake rate remained unchanged. The identification and elimination of the responsible acetyltransferase gene, as presented here, display key contributions of a superior
C. glutamicum
strain producing diaminopentane as a future building block for bio-based polyamides.