bluuebunny/crossref_metadata_2025_split huggingface dataset:
Paradoxical Atrial Undersensing Due to Inappropriate Atrial Noise Reversion of Atrial Fibrillation in Dual‐Chamber Pacemakers
Authors: KOLB CHRISTOF , HALBFAß PHILIPP , ZRENNER BERNHARD , SCHMITT CLAUS 
Published: July 2005

Background: Paradoxical atrial undersensing at high atrial sensing levels was described as false atrial noise reversion of dual‐chamber pacemakers during atrial fibrillation in a sheep model. It is unknown whether this phenomenon occurs in humans. Methods: In total, 71 patients with implanted dual‐chamber pacemakers and atrial fibrillation were tested for the occurrence of paradoxical atrial undersensing. After determination of the sensing threshold of atrial fibrillation (30 seconds of continuous mode switch), the atrial sensing level was stepwise increased. If, after correct mode switch behavior at insensitive levels, loss of mode switch occurred at higher sensing levels and if the pacing mode was consistent with atrial noise reversion, paradoxical atrial undersensing was assumed. Results: Paradoxical atrial undersensing could be provoked in 9 of 71 (13%) patients at a median sensing level of 0.4 (range 0.15–2.0) mV. Six different pacemaker models of five different manufacturers were affected. The occurrence of paradoxical atrial undersensing was significantly associated with the sensing threshold of atrial fibrillation (2.7 ± 1.5 mV for patients with paradoxical undersensing compared to 1.6 ± 1.3 mV for those without, P = 0.02). Decreasing the atrial sensing level avoided paradoxical undersensing in 8 of 9 patients while maintaining an adequate safety margin for the detection of atrial fibrillation. Conclusion: Paradoxical atrial undersensing is inherent to all current dual‐chamber pacemakers. The incidence is about 13% when using very high atrial sensing levels. Inappropriate atrial noise reversion can be resolved in most of the cases by decreasing atrial sensing levels and knowledge of this phenomenon is important to avoid unwarranted atrial lead revisions.
MICROBIOLOGY AND NUTRITIONAL COMPOSITION OF AN EDIBLE LARVA (BUNAEA ALCINOE STOLL) OF THE NIGER DELTA
Authors: AMADI E.N. , OGBALU O.K. , BARIMALAA I.S. , PIUS M. 
Published: July 2005

ABSTRACT The microbial load and nutritional composition of the Bunaea alcinoe larvae were investigated. The bacterial population of the skin and intestinal content were 8.16 × 106and 5.70 × 105 cfu/g while the fungal populations were 2.07 × 106and 1.32 × 106 cfu/g, respectively. Twenty bacterial isolates belonging to the genera Staphylococcus, Bacillus, Micrococcus and Acinetobacter were isolated. Staphylococcus aureus occurred on both the skin and intestinal content. The nutritional composition of the larvae revealed high protein (55%) followed by fat (25%). Total available carbohydrate, moisture and ash were 4, 8 and 8%, respectively. The public health implication of the presence of S. aureus is highlighted. B. alcinoe larva is a rich source of protein and can be recommended in the diet of communities where protein is scarce or expensive.
EFFECT OF MODIFIED ATMOSPHERE PACKAGING AND TEMPERATURE ON THE SHELF LIFE OF SLICED PASTIRMA PRODUCED FROM FROZEN/THAWED MEAT
Authors: AKSU MUHAMMET İRFAN , KAYA MÜKERREM , OCKERMAN HERBERT W. 
Published: July 2005

ABSTRACT Pastirma is a dry‐cured meat product and is categorized as an intermediate moisture food. Nonsliced pastirma can be stored without refrigeration. Pastirma is consumed sliced without cooking. For preservation of quality characteristics, sliced pastirma needs to be packaged and stored at fairly low temperatures (<10C). In this study, pastirma was made from frozen M. Longissimus dorsi muscle stored at−18C for 240 days and then thawed at 10C for 24 h. Pastirma produced from frozen/thawed meat was sliced. The sliced pastirma samples were stored in modified atmosphere packaging (MAP) (50% N2 + 50% CO2) at 4C and 10C for 150 days and thiobarbutiric acid reactive substances, free fatty acids, nonprotein nitrogen, pH, L*, a* and b* values, total aerobic and lactic acid bacteria, Micrococcus/Staphylococcus, yeast‐mold, and Enterobacteriaceae counts in sliced product were determined during storage (0, 30, 60, 90, 120 and 150 days). Results showed that sliced pastirma samples made from frozen/thawed meat and MAP can be stored at 4C and 10C for 150 days.
TRANSPORT AND STUNNING AFFECT QUALITY OF ARCTIC CHAR FILLETS
Authors: JITTINANDANA S. , KENNEY P.B. , MAZIK P.M. , DANLEY M. , NELSON C.D. , KISER R.A. , HANKINS J.A. 
Published: July 2005

ABSTRACT Arctic char transport was conducted using AQUI‐S, gas carbon dioxide (CO

2

), ice slurry or water for 5.5 h followed by CO

2

or by percussive stunning. The treatment without transport represented the control. At harvest and at 24‐h postmortem, transport in an ice slurry followed by percussive stunning resulted in the highest muscle pH; CO

2

stunning reduced muscle pH regardless of transport treatment. At 24‐h postmortem, the control treatment resulted in the firmest cooked products, while other transport conditions did not affect texture. Stunning with CO

2

produced a firmer texture compared with percussive stunning for cooked products derived from 24‐h and 4‐day postmortem refrigerated fillets. The transport treatment and the stunning method did not affect the muscle pH after a 4‐day storage at 3C.
INFLUENCE OF DIETARY MANGANESE SOURCE AND SUPPLEMENTATION LEVEL ON PORK QUALITY DURING RETAIL DISPLAY
Authors: APPLE JASON K. , ROBERTS W. JOSHUA , MAXWELL CHARLES V. , BOGER CHARLES B. , FRIESEN KIM G. , RAKES LILLY K. , FAKLER TIM M. 
Published: July 2005

ABSTRACT Pork loins were used to test the effects of dietary manganese source and supplementation level on pork quality traits during retail display. Chops from pigs fed 350 ppm Mn from Availa‐Mn received higher (P < 0.05) Japanese color scores, and, after 4 days of retail display, were less discolored than chops from pigs fed the control diet or diets containing manganese sulfate (MnSO4) (diet × display; P = 0.092). Chops from pigs fed 350 ppm Mn from MnSO4lost less moisture after 2 days of display (diet × display; P = 0.058), and tended to have lower (P < 0.10) thiobarbituric acid reactive substances values than chops from pigs fed the control diets or diets supplemented with 700 ppm Mn from Availa‐Mn. The results indicate that feeding an additional 350 ppm Mn may enhance pork quality; however, the dietary inclusion of 700 ppm Mn, regardless of source, had no beneficial effects on pork color or lipid oxidation.
OusB, a Broad-Specificity ABC-Type Transporter fromErwinia chrysanthemi, Mediates Uptake of Glycine Betaine and Choline with a High Affinity
Authors: Choquet Gwénaëlle , Jehan Nathalie , Pissavin Christine , Blanco Carlos , Jebbar Mohamed 
Published: July 2005

ABSTRACTThe ability ofErwinia chrysanthemito cope with environments of elevated osmolality is due in part to the transport and accumulation of osmoprotectants. In this study we have identified a high-affinity glycine betaine and choline transport system inE. chrysanthemi. By using a pool of Tn5-B21ousAmutants, we isolated a mutant that could grow in the presence of a toxic analogue of glycine betaine (benzyl-glycine betaine) at high osmolalities. This mutant was impaired in its ability to transport all effective osmoprotectants inE. chrysanthemi. The DNA sequence of the regions flanking the transposon insertion site revealed three chromosomal genes (ousVWX) that encode components of an ABC-type transporter (OusB): OusV (ATPase), OusW (permease), and OusX (periplasmic binding protein). The OusB components showed a significant degree of sequence identity to components of ProU fromSalmonella entericaserovar Typhimurium andEscherichia coli. OusB was found to restore the uptake of glycine betaine and choline through functional complementation of anE. colimutant defective in both ProU and ProP osmoprotectant uptake systems. Competition experiments demonstrated that choline, dimethylsulfoniacetate, dimethylsulfoniopropionate, and ectoine were effective competitors for OusB-mediated betaine transport but that carnitine, pipecolate, and proline were not effective. In addition, the analysis of single and double mutants showed that OusA and OusB were the only osmoprotectant transporters operating inE. chrysanthemi.
Combined Effect of High-Pressure Treatments and Bacteriocin-Producing Lactic Acid Bacteria on Inactivation of
Escherichia coli
O157:H7 in Raw-Milk Cheese
Authors: Rodriguez Eva , Arques Juan L. , Nuñez Manuel , Gaya Pilar , Medina Margarita 
Published: July 2005

ABSTRACT

The effect of high-pressure (HP) treatments combined with bacteriocins of lactic acid bacteria (LAB) produced in situ on the survival of
Escherichia coli
O157:H7 in cheese was investigated. Cheeses were manufactured from raw milk inoculated with
E. coli
O157:H7 at approximately 10
5
CFU/ml. Seven different bacteriocin-producing LAB were added at approximately 10
6
CFU/ml as adjuncts to the starter. Cheeses were pressurized on day 2 or 50 at 300 MPa for 10 min or 500 MPa for 5 min, at 10°C in both cases. After 60 days,
E. coli
O157:H7 counts in cheeses manufactured without bacteriocin-producing LAB and not pressurized were 5.1 log CFU/g. A higher inactivation of
E. coli
O157:H7 was achieved in cheeses without bacteriocin-producing LAB when 300 MPa was applied on day 50 (3.8-log-unit reduction) than if applied on day 2 (1.3-log-unit reduction). Application of 500 MPa eliminated
E. coli
O157:H7 in 60-day-old cheeses. Cheeses made with bacteriocin-producing LAB and not pressurized showed a slight reduction of the pathogen. Pressurization at 300 MPa on day 2 and addition of lacticin 481-, nisin A-, bacteriocin TAB 57-, or enterocin AS-48-producing LAB were synergistic and reduced
E. coli
O157:H7 counts to levels below 2 log units in 60-day-old cheeses. Pressurization at 300 MPa on day 50 and addition of nisin A-, bacteriocin TAB 57-, enterocin I-, or enterocin AS-48-producing LAB completely inactivated
E. coli
O157:H7 in 60-day-old cheeses. The application of reduced pressures combined with bacteriocin-producing LAB is a feasible procedure to improve cheese safety.
Stable Isotope Fractionation of Tetrachloroethene during Reductive Dechlorination by
Sulfurospirillum multivorans
and
Desulfitobacterium
sp. Strain PCE-S and Abiotic Reactions with Cyanocobalamin
Authors: Nijenhuis Ivonne , Andert Janet , Beck Kirsten , Kästner Matthias , Diekert Gabriele , Richnow Hans-Hermann 
Published: July 2005

ABSTRACT

Carbon stable isotope fractionation of tetrachloroethene (PCE) during reductive dechlorination by whole cells and crude extracts of
Sulfurospirillum multivorans
and
Desulfitobacterium
sp. strain PCE-S and the abiotic reaction with cyanocobalamin (vitamin B
12
) was studied. Fractionation was largest during the reaction with cyanocobalamin with αC = 1.0132. Stable isotope fractionation was lower but still in a similar order of magnitude for
Desulfitobacterium
sp. PCE-S (αC = 1.0052 to 1.0098). The isotope fractionation of PCE during dehalogenation by
S. multivorans
was lower by 1 order of magnitude (αC = 1.00042 to 1.0017). Additionally, an increase in isotope fractionation was observed with a decrease in cell integrity for both strains. For
Desulfitobacterium
sp. strain PCE-S, the carbon stable isotope fractionation factors were 1.0052 and 1.0089 for growing cells and crude extracts, respectively. For
S. multivorans
, αC values were 1.00042, 1.00097, and 1.0017 for growing cells, crude extracts, and the purified PCE reductive dehalogenase, respectively. For the field application of stable isotope fractionation, care is needed as fractionation may vary by more than an order of magnitude depending on the bacteria present, responsible for degradation.
Enhancement of the Efficiency of Secretion of Heterologous Lipase in
Escherichia coli
by Directed Evolution of the ABC Transporter System
Authors: Eom Gyeong Tae , Song Jae Kwang , Ahn Jung Hoon , Seo Yeon Soo , Rhee Joon Shick 
Published: July 2005

ABSTRACT

The ABC transporter (TliDEF) from
Pseudomonas fluorescens
SIK W1, which mediated the secretion of a thermostable lipase (TliA) into the extracellular space in
Escherichia coli
, was engineered using directed evolution (error-prone PCR) to improve its secretion efficiency. TliD mutants with increased secretion efficiency were identified by coexpressing the mutated
tliD
library with the wild-type
tliA
lipase in
E. coli
and by screening the library with a tributyrin-emulsified indicator plate assay and a microtiter plate-based assay. Four selected mutants from one round of error-prone PCR mutagenesis, T6, T8, T24, and T35, showed 3.2-, 2.6-, 2.9-, and 3.0-fold increases in the level of secretion of TliA lipase, respectively, but had almost the same level of expression of TliD in the membrane as the strain with the wild-type TliDEF transporter. These results indicated that the improved secretion of TliA lipase was mediated by the transporter mutations. Each mutant had a single amino acid change in the predicted cytoplasmic regions in the membrane domain of TliD, implying that the corresponding region of TliD was important for the improved and successful secretion of the target protein. We therefore concluded that the efficiency of secretion of a heterologous protein in
E. coli
can be enhanced by in vitro engineering of the ABC transporter.
Role of Porins in Sensitivity of
Escherichia coli
to Antibacterial Activity of the Lactoperoxidase Enzyme System
Authors: De Spiegeleer Philipp , Sermon Jan , Vanoirbeek Kristof , Aertsen Abram , Michiels Chris W. 
Published: July 2005

ABSTRACT

Lactoperoxidase is an enzyme that contributes to the antimicrobial defense in secretory fluids and that has attracted interest as a potential biopreservative for foods and other perishable products. Its antimicrobial activity is based on the formation of hypothiocyanate (OSCN
−
) from thiocyanate (SCN
−
), using H
2
O
2
as an oxidant. To gain insight into the antibacterial mode of action of the lactoperoxidase enzyme system, we generated random transposon insertion mutations in
Escherichia coli
MG1655 and screened the resultant mutants for an altered tolerance of bacteriostatic concentrations of this enzyme system. Out of the ca. 5,000 mutants screened, 4 showed significantly increased tolerance, and 2 of these had an insertion, one in the
waaQ
gene and one in the
waaO
gene, whose products are involved in the synthesis of the core oligosaccharide moiety of lipopolysaccharides. Besides producing truncated lipopolysaccharides and displaying hypersensitivity to novobiocin and sodium dodecyl sulfate (SDS), these mutants were also shown by urea-SDS-polyacrylamide gel electrophoresis analysis to have reduced amounts of porins in their outer membranes. Moreover, they showed a reduced degradation of
p
-nitrophenyl phosphate and an increased resistance to ampicillin, two indications of a decrease in outer membrane permeability for small hydrophilic solutes. Additionally,
ompC
and
ompF
knockout mutants displayed levels of tolerance to the lactoperoxidase system similar to those displayed by the
waa
mutants. These results suggest that mutations which reduce the porin-mediated outer membrane permeability for small hydrophilic molecules lead to increased tolerance to the lactoperoxidase enzyme system because of a reduced uptake of OSCN
−
.
Development of a Simple and Rapid Fluorogenic Procedure for Identification of
Vibrionaceae
Family Members
Authors: Richards Gary P. , Watson Michael A. , Parveen Salina 
Published: July 2005

ABSTRACT

We describe a simple colony overlay procedure for peptidases (COPP) for the rapid fluorogenic detection and quantification of
Vibrionaceae
from seawater, shellfish, sewage, and clinical samples. The assay detects phosphoglucose isomerase with a lysyl aminopeptidase activity that is produced by
Vibrionaceae
family members. Overnight cultures are overlaid for 10 min with membranes containing a synthetic substrate, and the membranes are examined for fluorescent foci under UV illumination. Fluorescent foci were produced by all the
Vibrionaceae
tested, including
Vibrio
spp.,
Aeromonas
spp., and
Plesiomonas
spp. Fluorescence was not produced by non-
Vibrionaceae
pathogens.
Vibrio cholerae
strains O1, O139, O22, and O155 were strongly positive. Seawater and oysters were assayed, and 87 of 93 (93.5%) of the positive isolates were identified biochemically as
Vibrionaceae
, principally
Vibrio vulnificus
,
Vibrio parahaemolyticus
,
Aeromonas hydrophila
,
Photobacterium damselae
, and
Shewanella putrefaciens
. None of 50 nonfluorescent isolates were
Vibrionaceae
. No
Vibrionaceae
were detected in soil, and only
A. hydrophila
was detected in sewage. The COPP technique may be particularly valuable in environmental and food-testing laboratories and for monitoring water quality in the aquaculture industry.
Identification and Characterization of a SecondlexAGene ofXanthomonas axonopodisPathovar citri
Authors: Yang Mei-Kwei , Su Shu-Ray , Sung Vin-Long 
Published: July 2005

ABSTRACTWe previously identified and characterized alexAgene fromXanthomonas axonopodispv. citri. For this study, we cloned and expressed alexAhomologue fromX. axonopodispv. citri. This gene was designatedlexA2, and the previously identifiedlexAgene was renamedlexA1. The coding region oflexA2is 606 bp long and shares 59% nucleotide sequence identity withlexA1. Analyses of the deduced amino acid sequence revealed that LexA2 has structures that are characteristic of LexA proteins, including a helix-turn-helix DNA binding domain and conserved amino acid residues required for the autocleavage of LexA. ThelexA2mutant, which was constructed by gene replacement, was 4 orders of magnitude more resistant to the DNA-damaging agent mitomycin C at 0.1 μg/ml and 1 order of magnitude more resistant to another DNA-damaging agent, methylmethane sulfonate at 30 μg/ml, than the wild type. AlexA1 lexA2double mutant had the same degree of susceptibility to mitomycin C as thelexA1orlexA2single mutant but was 1 order of magnitude more resistant to methylmethane sulfonate at 30 μg/ml than thelexA1orlexA2single mutant. These results suggest that LexA1 and LexA2 play different roles in regulating the production of methyltransferases that are required for repairing DNA damage caused by methylmethane sulfonate. A mitomycin C treatment also caused LexA2 to undergo autocleavage, as seen with LexA1. The results of electrophoresis mobility shift assays revealed that LexA2 does not bind thelexA1promoter. It binds to both thelexA2andrecApromoters. However, neither LexA2 nor LexA1 appears to regulaterecAexpression, aslexA1,lexA2, andlexA1 lexA2mutants did not become constitutive forrecAtranscription and RecA production. These results suggest thatrecAexpression inX. axonopodispv. citri is regulated by mechanisms that have yet to be identified.
Algal Viruses with Distinct Intraspecies Host Specificities Include Identical Intein Elements
Authors: Nagasaki Keizo , Shirai Yoko , Tomaru Yuji , Nishida Kensho , Pietrokovski Shmuel 
Published: July 2005

ABSTRACT

Heterosigma akashiwo
virus (HaV) is a large double-stranded DNA virus infecting the single-cell bloom-forming raphidophyte (golden brown alga)
H. akashiwo
. A molecular phylogenetic sequence analysis of HaV DNA polymerase showed that it forms a sister group with
Phycodnaviridae
algal viruses. All 10 examined HaV strains, which had distinct intraspecies host specificities, included an intein (protein intron) in their DNA polymerase genes. The 232-amino-acid inteins differed from each other by no more than a single nucleotide change. All inteins were present at the same conserved position, coding for an active-site motif, which also includes inteins in mimivirus (a very large double-stranded DNA virus of amoebae) and in several archaeal DNA polymerase genes. The HaV intein is closely related to the mimivirus intein, and both are apparently monophyletic to the archaeal inteins. These observations suggest the occurrence of horizontal transfers of inteins between viruses of different families and between archaea and viruses and reveal that viruses might be reservoirs and intermediates in horizontal transmissions of inteins. The homing endonuclease domain of the HaV intein alleles is mostly deleted. The mechanism keeping their sequences basically identical in HaV strains specific for different hosts is yet unknown. One possibility is that rapid and local changes in the HaV genome change its host specificity. This is the first report of inteins found in viruses infecting eukaryotic algae.
Metabolic Engineering of Anthocyanin Biosynthesis in
Escherichia coli
Authors: Yan Yajun , Chemler Joseph , Huang Lixuan , Martens Stefan , Koffas Mattheos A. G. 
Published: July 2005

ABSTRACT

Anthocyanins are red, purple, or blue plant pigments that belong to the family of polyphenolic compounds collectively called flavonoids. Their demonstrated antioxidant properties and economic importance to the dye, fruit, and cut-flower industries have driven intensive research into their metabolic biosynthetic pathways. In order to produce stable, glycosylated anthocyanins from colorless flavanones such as naringenin and eriodictyol, a four-step metabolic pathway was constructed that contained plant genes from heterologous origins: flavanone 3β-hydroxylase from
Malus domestica
, dihydroflavonol 4-reductase from
Anthurium andraeanum
, anthocyanidin synthase (ANS) also from
M. domestica
, and UDP-glucose:flavonoid 3-
O
-glucosyltransferase from
Petunia hybrida
. Using two rounds of PCR, each one of the four genes was first placed under the control of the
trc
promoter and its own bacterial ribosome-binding site and then cloned sequentially into vector pK184.
Escherichia coli
cells containing the recombinant plant pathway were able to take up either naringenin or eriodictyol and convert it to the corresponding glycosylated anthocyanin, pelargonidin 3-
O
-glucoside or cyanidin 3-
O
-glucoside. The produced anthocyanins were present at low concentrations, while most of the metabolites detected corresponded to their dihydroflavonol precursors, as well as the corresponding flavonols. The presence of side product flavonols is at least partly due to an alternate reaction catalyzed by ANS. This is the first time plant-specific anthocyanins have been produced from a microorganism and opens up the possibility of further production improvement by protein and pathway engineering.
Effect of 26-Oxygenosterols from
Ganoderma lucidum
and Their Activity as Cholesterol Synthesis Inhibitors
Authors: Hajjaj Hassan , Macé Catherine , Roberts Matthew , Niederberger Peter , Fay Laurent B. 
Published: July 2005

ABSTRACT

Ganoderma lucidum
is a medicinal fungus belonging to the Polyporaceae family which has long been known in Japan as Reishi and has been used extensively in traditional Chinese medicine. We report the isolation and identification of the 26-oxygenosterols ganoderol A, ganoderol B, ganoderal A, and ganoderic acid Y and their biological effects on cholesterol synthesis in a human hepatic cell line in vitro. We also investigated the site of inhibition in the cholesterol synthesis pathway. We found that these oxygenated sterols from
G. lucidum
inhibited cholesterol biosynthesis via conversion of acetate or mevalonate as a precursor of cholesterol. By incorporation of 24,25-dihydro-[24,25-
3
H
2
]lanosterol and [3-
3
H]lathosterol in the presence of ganoderol A, we determined that the point of inhibition of cholesterol synthesis is between lanosterol and lathosterol. These results demonstrate that the lanosterol 14α-demethylase, which converts 24,25-dihydrolanosterol to cholesterol, can be inhibited by the 26-oxygenosterols from
G. lucidum
. These 26-oxygenosterols could lead to novel therapeutic agents that lower blood cholesterol.