bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enhanced detection of hepatitis B virus in Hong Kong blood donors after introduction of a more sensitive transcription‐mediated amplification assay
Authors: Tsoi Wai‐Chiu , Lelie Nico , Lin Che‐Kit 
Published: March 2013

BackgroundA total of 517,072 and 399,326 consecutive donations were screened for hepatitis B virus (HBV) by individual‐donation nucleic acid testing (ID‐NAT) using Ultrio and Ultrio Plus assays (Novartis Diagnostics), respectively. The impact of more sensitive HBV detection by the latter assay version was established by comparing NAT yield and transmission risk.Study Design and MethodsDonations were screened simultaneously for HBV serologic markers and ID‐NAT, followed by discriminatory assay and confirmatory test algorithms. Window period (WP) reduction and residual HBV transmission risk were computed using mathematical modeling.ResultsHBV NAT‐yield rates for both WP and occult HBV infection (OBI) increased significantly from 1:34,471 to 1:17,362 (p = 0.036) and from 1:5120 to 1:2450 (p < 0.0001), despite a 1.2‐ and 1.6‐fold decrease in hepatitis B surface antigen (HBsAg) incidence and prevalence rates respectively. After adjusting for this bias, the WP and OBI NAT‐yield improvement factors were 2.3 and 3.4, respectively, higher than a less than 1.5‐fold increase estimated from analytical sensitivity studies on HBV Genotype A and C standards. The current WP transmission risk with Ultrio Plus screening was estimated at 1:55,000 compared to 1:22,000 with HBsAg testing.ConclusionThe observed greater than twofold enhanced WP NAT yield with the Ultrio Plus assay can be explained by greater than 10‐fold increased analytical sensitivity in detecting the HBV Genotype B and C strains in Hong Kong. Direct comparison studies of the two assay versions on dilutions of HBV NAT‐yield samples are required to confirm this hypothesis.
Use of tranexamic acid results in decreased blood loss and decreased transfusions in patients undergoing staged bilateral total knee arthroplasty
Authors: Kelley Todd C. , Tucker Kimberly K. , Adams Mary Jo , Dalury David F. 
Published: March 2013

BackgroundTranexamic acid (TXA) is an antifibrinolytic that reduces blood loss and transfusion rates in total joint arthroplasty. Blood loss and allogenic transfusion rates have not been well studied in patients receiving TXA and undergoing bilateral staged total knee arthroplasty (TKA). The purpose was to evaluate the effect of TXA on blood loss, hemoglobin (Hb) changes, and transfusion in patients undergoing staged bilateral TKA.Study Design and MethodsThe authors compared 51 patients undergoing staged bilateral TKA who received TXA (2 g; subjects) with 70 who did not (controls). There were no significant differences between the groups in terms of demographics or preoperative Hb. For each TKA, 1 g of TXA was administered intravenously 15 minutes before incision and 1 g was administered intravenously at tourniquet release. Blood loss, Hb levels, and transfusions were recorded. Statistical analyses were performed using computer software. Significance was set at 0.05.ResultsSubjects had a significantly lower (p < 0.001) mean (±SD) blood loss (373.8 ± 264.6 mL vs. 871.6 ± 457.7 mL), significantly higher (p < 0.005) Hb levels on Postoperative Days 1 and 2, and a significantly lower (p < 0.001) mean (±SD) number of transfused allogenic blood units (0.60 ± 0.84 units vs. 1.53 ± 1.30 units).ConclusionsTXA reduces blood loss, improves postoperative Hb, and decreases the allogenic blood transfusion requirements for patients undergoing bilateral staged TKA. TXA is an option for patients choosing bilateral staged TKA to decrease the risks associated with blood transfusion or when autologous blood is not available.
Molecular genetic analysis of ABO blood group variations reveals 29 novel ABO subgroup alleles
Authors: Cai Xiaohong , Jin Sha , Liu Xi , Fan Liangfeng , Lu Qiong , Wang Jianlian , Shen Wei , Gong Songsong , Qiu Li , Xiang Dong 
Published: March 2013

BackgroundIdentifying genetic variants of the ABO gene may reveal new biologic mechanisms underlying variant phenotypes of the ABO blood group. We report the molecular genetic analysis of 322 apparently unrelated ABO subgroup individuals in an estimated 2.1 million donors.Study Design and MethodsWe performed phenotype investigations by serology studies, analyzed the DNA sequence of the ABO gene by direct sequencing or sequencing after cloning, and evaluated promoter activity by reporter assays.ResultsIn 62 rare ABO alleles, we identified 29 novel ABO subgroup alleles in 43 apparently unrelated subgroup individuals and their four available pedigrees. Of these alleles, one was a deletion‐mutation allele, four were hybrid alleles, and 24 were point‐mutation alleles. Most of the point mutations were detected in Exons 6 to 7, while several others were also detected in Exons 1 to 5 or splicing regions. One ABO promoter mutation, −35 to −18 del, was found and verified to reduce promoter activity, as determined by dual luciferase assays. Two mutations, 7G>T and 52C>T, carrying the premature terminal codons E3X and R18X in the 5′‐region, were found to be associated with the very weak ABO subgroups “Ael” and “Bel.”ConclusionTwenty‐nine ABO subgroup alleles were newly linked to different kinds of ABO variations. We provide the first evidence that promoter abnormality is involved in the formation of weak ABO phenotypes. We also described the first naturally occurring ABO alleles with premature terminal codons in the 5′‐region that led to Ael and Bel phenotypes.
Riboflavin and ultraviolet light treatment of platelets triggers p38MAPK signaling: inhibition significantly improves in vitro platelet quality after pathogen reduction treatment
Authors: Schubert Peter , Coupland Danielle , Culibrk Brankica , Goodrich Raymond P. , Devine Dana V. 
Published: March 2013

BackgroundPathogen reduction technologies (PRTs) significantly reduce the risk of transmission of infectious agents in platelet (PLT) concentrates; however, in vitro studies reveal a negative impact on PLT quality after PRT treatment including effects on PLT aggregation, integrin αIIbβ3 conformation, and actin dynamics. Clinically, the interval between transfusions is shortened.Study Design and MethodsSeeking to understand the biochemical mechanisms underlying these observed effects, we analyzed signal transduction in PLT concentrates after riboflavin and ultraviolet light (UV; Mirasol) treatment and subsequent storage focusing on the phosphorylation levels of selected protein kinases.ResultsAmong identified candidates, p38MAPK increased fourfold in phosphorylation after PRT. Incubation of PLT concentrates with a p38MAPK‐specific inhibitor before PRT significantly improved numerous PLT quality measures. Phosphorylation levels of the p38MAPK substrates AKT, VASP, and HSP27 also decreased with inhibitor treatment. Phospho‐HSP27 decrease in the presence of the inhibitor correlated with a reduction in PLT activation determined by surface expression of P‐selectin.ConclusionThese findings support a model of one dominant underlying molecular signaling mechanism that is impacted by the riboflavin and UV (Mirasol) PRT process resulting in alterations in PLT quality. The identification of such a target should assist in the development of strategies to ameliorate this negative aspect of an otherwise beneficial and important safety development for transfusion medicine.
Purinergic stimulation of carotid body efferent glossopharyngeal neurones increases intracellular Ca2+ and nitric oxide production
Authors: Lowe Michael , Park Sung Jin , Nurse Colin A. , Campanucci Verónica A. 
Published: March 2013

New Findings
What is the central question of this study?Nitric oxide is a strong modulator of carotid body (CB) chemoreceptor activity; however, the mechanisms leading to the production/release of NO during CB chemoexcitation remained largely unknown.
What is the main finding and what is its importance?In the present study, we identified an important contribution of ATP and purinergic P2X receptor signalling in initiating the events leading to NO synthesis and release in efferent neurons to the CB. Acting via P2X receptors, ATP causes an increase in intracellular Ca2+ that triggers NO production in efferent neurones to the rat carotid body. In addition, ATP‐induced depolarization of these neurones activates voltage‐gated Ca2+ channels that further amplify the NO inhibitory signal.
The mammalian carotid body (CB) is a peripheral chemosensory organ that controls ventilation and is innervated by both afferent and efferent nerve fibres. The afferent pathway is stimulated by chemoexcitants, such as hypoxia, hypercapnia and acidosis. The efferent pathway causes inhibition of the sensory discharge via release of NO that originates mainly from neuronal nitric oxide synthase (nNOS)‐positive autonomic neurones within the glossopharyngeal nerve (GPN). Recent studies in the rat indicate that these inhibitory GPN neurones and their processes express purinergic P2X receptors and can be activated by ATP, a key excitatory CB neurotransmitter. Here we tested the hypothesis that purinergic agonists stimulate a rise in [Ca2+]i, leading to nNOS activation and NO production in isolated GPN neurones, using the fluorescent probes fura‐2 and 4‐amino‐5‐methylamino‐2′,7′‐difluorofluorescein diacetate (DAF‐FM DA), respectively. ATP caused a dose‐dependent increase in [Ca2+]i in GPN neurones (EC50≈ 1.92 μm) that was markedly inhibited by a combination of 100 μm suramin (a non‐specific P2X blocker) and 100 nm Brilliant Blue G (a selective P2X7 blocker). ATP also stimulated NO production in GPN neurones, as revealed by an increase in DAF fluorescence; this NO signal was inhibited by purinergic blockers, chelators of extracellular Ca2+, the nNOS inhibitor l‐NAME and the NO scavenger carboxy‐PTIO. The P2X2/3 and P2X7 agonists α,β,‐methylene ATP and benzoyl ATP mimicked the effects of ATP. Taken together, these data indicate that ATP may contribute to negative feedback inhibition of CB sensory discharge via purinergic stimulation of NO production in efferent fibres.
Blockade of central orexin 2 receptors reduces arterial pressure in spontaneously hypertensive rats
Authors: Lee Yen‐Hsien , Dai Yu‐Wen E. , Huang Shang‐Cheng , Li Tzu‐Ling , Hwang Ling‐Ling 
Published: March 2013

New FindingsWhat is the central question of this study?Central orexinergic activity is involved in tonic and phasic control of cardiovascular homeostasis. A potential role for elevated central orexinergic activity in the maintenance of hypertension in spontaneously hypertensive rats (SHRs) has not previously been explored.What is the main finding and what is its importance?We show that central or intra‐rostral ventrolateral medulla blockade of orexin 2 receptors produces a significant reduction of arterial pressure in SHRs, but not Wistar–Kyoto rats. This study demonstrates a previously unrecognized role of orexin 2 receptors in maintaining hypertension in SHRs.Orexins can raise arterial pressure and sympathetic activity and are involved in tonic and phasic control of cardiovascular homeostasis. We hypothesized that elevated central orexinergic activity contributes to the maintenance of hypertension in spontaneously hypertensive rats (SHRs). We examined this hypothesis by suppressing central orexinergic activity in SHRs and Wistar–Kyoto rats (WKYs) with specific antagonists or antibodies against orexin 1 (OX1R) and 2 receptors (OX2R). Intracerebroventricular administration of an OX1R antagonist, SB‐334867 (30 and 100 nmol), induced no significant change in mean arterial pressure (MAP) and heart rate (HR) in SHRs and WKYs except that at 100 nmol it reduced HR in WKYs. In contrast, an OX2R antagonist, TCS‐OX2‐29 (3–30 nmol) induced long‐lasting reductions of MAP and HR in SHRs (21 ± 3 mmHg and 22 ± 2 beats min−1at 30 nmol), but not in WKYs. Intracerebroventricular anti‐OX2R IgG, but not anti‐OX1R IgG or non‐immune goat IgG, significantly lowered MAP and HR in SHRs. None of the three IgGs affected MAP or HR in WKYs. The OX2R protein level in the rostral ventrolateral medulla (RVLM) was lower in SHRs than in WKYs, whereas no differences were found between SHRs and WKYs in the paraventricular hypothalamic nucleus, dorsomedial‐perifornical hypothalamic area or caudal nucleus tractus solitarii. The OX1R protein levels in these four regions did not differ between SHRs and WKYs. Injection of TCS‐OX2‐29 (50 pmol) into the RVLM produced a larger reduction of MAP in SHRs than in WKYs. We conclude that elevated OX2R‐mediated activity in the brain, especially in the RVLM, may contribute to hypertension in SHRs.
New Insight into the Cleavage Reaction of Nostoc sp. Strain PCC 7120 Carotenoid Cleavage Dioxygenase in Natural and Nonnatural Carotenoids
Authors: Heo Jinsol , Kim Se Hyeuk , Lee Pyung Cheon 
Published: March 2013

ABSTRACT

Carotenoid cleavage dioxygenases (CCDs) are enzymes that catalyze the oxidative cleavage of carotenoids at a specific double bond to generate apocarotenoids. In this study, we investigated the activity and substrate preferences of NSC3, a CCD of
Nostoc
sp. strain PCC 7120,
in vivo
and
in vitro
using natural and nonnatural carotenoid structures. NSC3 cleaved β-apo-8′-carotenal at 3 positions, C-13

C-14, C-15

C-15′, and C-13′

C-14′, revealing a unique cleavage pattern. NSC3 cleaves the natural structure of carotenoids 4,4′-diaponeurosporene, 4,4′-diaponeurosporen-4′-al, 4,4′-diaponeurosporen-4′-oic acid, 4,4′-diapotorulene, and 4,4′-diapotorulen-4′-al to generate novel cleavage products (apo-14′-diaponeurosporenal, apo-13′-diaponeurosporenal, apo-10′-diaponeurosporenal, apo-14′-diapotorulenal, and apo-10′-diapotorulenal, respectively). The study of carotenoids with natural or nonnatural structures produced by using synthetic modules could provide information valuable for understanding the cleavage reactions or substrate preferences of other CCDs
in vivo
and
in vitro
.
Identification and Characterization of Three Previously Undescribed Crystal Proteins from Bacillus thuringiensis subsp.
jegathesan
Authors: Sun Yunjun , Zhao Qiang , Xia Liqiu , Ding Xuezhi , Hu Quanfang , Federici Brian A. , Park Hyun-Woo 
Published: March 2013

ABSTRACT

The total protoxin complement in the parasporal body of mosquitocidal strain,
Bacillus thuringiensis
subsp.
jegathesan
367, was determined by use of a polyacrylamide gel block coupled to mass spectrometry. A total of eight protoxins were identified from this strain, including five reported protoxins (Cry11Ba, Cry19Aa, Cry24Aa, Cry25Aa, and Cyt2Bb), as well as three previously undescribed (Cry30Ca, Cry60Aa, and Cry60Ba) in this isolate. It was interesting that the encoding genes of three new protoxins existed as
cry30Ca
-gap-
orf2
and
cry60Ba
-gap-
cry60Aa
. The
cry30Ca
and a downstream
orf2
gene were oriented in the same direction and separated by 114 bp, and
cry60Ba
was located 156 bp upstream from and in the same orientation to
cry60Aa
. The three new protoxin genes were cloned from
B. thuringiensis
subsp.
jegathesan
and expressed in an acrystalliferous strain under the control of
cyt1A
gene promoters and the STAB-SD stabilizer sequence. Recombinant strain containing only
cry30Ca
did not produce visible inclusion under microscope observation, while that containing both
cry30Ca
and
orf2
could produce large inclusions. Cry60Aa and Cry60Ba synthesized either alone or together in the acrystalliferous host could yield large inclusions. In bioassays using the fourth-instar larvae of
Culex quinquefasciatus
, Cry60Aa and Cry60Ba alone or together had estimated 50% lethal concentrations of 2.9 to 7.9 μg/ml; however, Cry30Ca with or without ORF2 was not toxic to this mosquito.
Improvement of Natamycin Production by Engineering of Phosphopantetheinyl Transferases in Streptomyces chattanoogensis L10
Authors: Jiang Hui , Wang Yue-Yue , Ran Xin-Xin , Fan Wei-Ming , Jiang Xin-Hang , Guan Wen-Jun , Li Yong-Quan 
Published: March 2013

ABSTRACT

Phosphopantetheinyl transferases (PPTases) are essential to the activities of type I/II polyketide synthases (PKSs) and nonribosomal peptide synthetases (NRPSs) through converting acyl carrier proteins (ACPs) in PKSs and peptidyl carrier proteins (PCPs) in NRPSs from inactive apo-forms into active holo-forms, leading to biosynthesis of polyketides and nonribosomal peptides. The industrial natamycin (NTM) producer,
Streptomyces chattanoogensis
L10, contains two PPTases (SchPPT and SchACPS) and five PKSs. Biochemical characterization of these two PPTases shows that SchPPT catalyzes the phosphopantetheinylation of ACPs in both type I PKSs and type II PKSs, SchACPS catalyzes the phosphopantetheinylation of ACPs in type II PKSs and fatty acid synthases (FASs), and the specificity of SchPPT is possibly controlled by its C terminus. Inactivation of SchPPT in
S. chattanoogensis
L10 abolished production of NTM but not the spore pigment, while overexpression of the SchPPT gene not only increased NTM production by about 40% but also accelerated productions of both NTM and the spore pigment. Thus, we elucidated a comprehensive phosphopantetheinylation network of PKSs and improved polyketide production by engineering the cognate PPTase in bacteria.
Potato Crop as a Source of Emetic Bacillus cereus and Cereulide-Induced Mammalian Cell Toxicity
Authors: Hoornstra Douwe , Andersson Maria A. , Teplova Vera V. , Mikkola Raimo , Uotila Liisa M. , Andersson Leif C. , Roivainen Merja , Gahmberg Carl G. , Salkinoja-Salonen Mirja S. 
Published: March 2013

ABSTRACT

Bacillus cereus
, aseptically isolated from potato tubers, were screened for cereulide production and for toxicity on human and other mammalian cells. The cereulide-producing isolates grew slowly, the colonies remained small (∼1 mm), tested negative for starch hydrolysis, and varied in productivity from 1 to 100 ng of cereulide mg (wet weight)
−1
(∼0.01 to 1 ng per 10
5
CFU). By DNA-fingerprint analysis, the isolates matched
B. cereus
F5881/94, connected to human food-borne illness, but were distinct from cereulide-producing endophytes of spruce tree (
Picea abies
). Exposure to cell extracts (1 to 10 μg of bacterial biomass ml
−1
) and to purified cereulide (0.4 to 7 ng ml
−1
) from the potato isolates caused mitochondrial depolarization (loss of ΔΨm) in human peripheral blood mononuclear cells (PBMC) and keratinocytes (HaCaT), porcine spermatozoa and kidney tubular epithelial cells (PK-15), murine fibroblasts (L-929), and pancreatic insulin-producing cells (MIN-6). Cereulide (10 to 20 ng ml
−1
) exposed pancreatic islets (MIN-6) disintegrated into small pyknotic cells, followed by necrotic death. Necrotic death in other test cells was observed only after a 2-log-higher exposure. Exposure to 30 to 60 ng of cereulide ml
−1
induced K
+
translocation in intact, live PBMC, keratinocytes, and sperm cells within seconds of exposure, depleting 2 to 10% of the cellular K
+
stores within 10 min. The ability of cereulide to transfer K
+
ions across biological membranes may benefit the producer bacterium in K
+
-deficient environments such as extracellular spaces inside plant tissue but is a pathogenic trait when in contact with mammalian cells.
Inactivation of the
panE
Gene in Lactococcus lactis Enhances Formation of Cheese Aroma Compounds
Authors: de Cadiñanos Luz P. Gómez , García-Cayuela Tomás , Yvon Mireille , Martinez-Cuesta M. Carmen , Peláez Carmen , Requena Teresa 
Published: March 2013

ABSTRACT

Hydroxyacid dehydrogenases limit the conversion of α-keto acids into aroma compounds. Here we report that inactivation of the
panE
gene, encoding the α-hydroxyacid dehydrogenase activity in
Lactococcus lactis
, enhanced the formation of 3-methylbutanal and 3-methylbutanol.
L. lactis
IFPL953Δ
panE
was an efficient strain producing volatile compounds related to cheese aroma.
Improved Transferase/Hydrolase Ratio through Rational Design of a Family 1 β-Glucosidase from Thermotoga neapolitana
Authors: Lundemo Pontus , Adlercreutz Patrick , Karlsson Eva Nordberg 
Published: March 2013

ABSTRACT

Alkyl glycosides are attractive surfactants because of their high surface activity and good biodegradability and can be produced from renewable resources. Through enzymatic catalysis, one can obtain well-defined alkyl glycosides, something that is very difficult to do using conventional chemistry. However, there is a need for better enzymes to get a commercially feasible process. A thermostable β-glucosidase from the well-studied glycoside hydrolase family 1 from
Thermotoga neapolitana
,
Tn
Bgl1A, was mutated in an attempt to improve its value for synthesis of alkyl glycosides. This was done by rational design using prior knowledge from structural homologues together with a recently generated model of the enzyme in question. Three out of four studied mutations increased the hydrolytic reaction rate in an aqueous environment, while none displayed this property in the presence of an alcohol acceptor. This shows that even if the enzyme resides in a separate aqueous phase, the presence of an organic solvent has a great influence. We could also show that a single amino acid replacement in a less studied part of the aglycone subsite, N220F, improves the specificity for transglycosylation 7-fold and thereby increases the potential yield of alkyl glycoside from 17% to 58%.
Distribution and Functions of Phosphotransferase System Genes in the Genome of the Lactic Acid Bacterium Oenococcus oeni
Authors: Jamal Zohra , Miot-Sertier Cécile , Thibau François , Dutilh Lucie , Lonvaud-Funel Aline , Ballestra Patricia , Le Marrec Claire , Dols-Lafargue Marguerite 
Published: March 2013

ABSTRACT

Oenococcus oeni
, the lactic acid bacterium primarily responsible for malolactic fermentation in wine, is able to grow on a large variety of carbohydrates, but the pathways by which substrates are transported and phosphorylated in this species have been poorly studied. We show that the genes encoding the general phosphotransferase proteins, enzyme I (EI) and histidine protein (HPr), as well as 21 permease genes (3 isolated ones and 18 clustered into 6 distinct loci), are highly conserved among the strains studied and may form part of the
O. oeni
core genome. Additional permease genes differentiate the strains and may have been acquired or lost by horizontal gene transfer events. The core
pts
genes are expressed, and permease gene expression is modulated by the nature of the bacterial growth substrate. Decryptified
O. oeni
cells are able to phosphorylate glucose, cellobiose, trehalose, and mannose at the expense of phosphoenolpyruvate. These substrates are present at low concentrations in wine at the end of alcoholic fermentation. The phosphotransferase system (PTS) may contribute to the perfect adaptation of
O. oeni
to its singular ecological niche.