bluuebunny/crossref_metadata_2025_split huggingface dataset:
Male Partners' Role in Latinas' Amniocentesis Decisions
Authors: Browner Carole H. , Preloran H. Mabel 
Published: April 2003

AbstractThere has been relatively little research on men's experiences with fetal diagnosis or their role in their female partners' decisions about whether to be tested. This issue may be of particular salience in the delivery of genetic services to Latino groups, where it is often assumed that lower rates of genetic service utilization are linked to men's refusal to allow their wives to be tested. Here we present data from a multimethod study on the use of amniocentesis by Mexican‐origin women in Southern California. We focus on the role male partners played in the women's amniocentesis decisions. Contrary to expectation, we found that women made the majority of the decisions about amniocentesis, although their partners' presence at the genetic consultation where the amniocentesis was offered proved an important predictive factor in amniocentesis uptake.
For the Insect Pathogen
Photorhabdus luminescens
, Which End of a Nematode Is Out?
Authors: Ciche Todd A. , Ensign Jerald C. 
Published: April 2003

ABSTRACT

The nematode
Heterorhabditis bacteriophora
is the vector for transmitting the entomopathogenic bacterium
Photorhabdus luminescens
between insect larvae. The dauer juvenile (DJ) stage nematode selectively retains
P. luminescens
in its intestine until it releases the bacteria into the hemocoel of an insect host. We report the results of studying the transmission of the bacteria by its nematode vector. Cells of
P. luminescens
labeled with green fluorescent protein preferentially colonized a region of the DJ intestine immediately behind the basal bulb, extending for various distances toward the anus. Incubation of DJ nematodes in vitro in insect hemolymph induced regurgitation of the bacteria. Following a 30-min lag, the bacteria migrated in a gradual and staggered movement toward and ultimately exited the mouth. This regurgitation reaction was induced by a low-molecular-weight, heat- and protease-stable, anionic component present in arthropod hemolymph and in supernatants from insect cell cultures. Nematodes anesthetized with levamisole or treated with the antihelmenthic agent ivermectin did not release their bacteria into hemolymph. The ability to visualize
P. luminescens
in the DJ nematode intestine provides the first clues to the mechanism of release of the bacteria during infection of insect larvae. This and the partial characterization of a component of hemolymph triggering release of the bacteria render this fascinating example of both a mutualistic symbiosis and disease transmission amenable to future genetic and molecular study.
Absence of Malolactic Activity Is a Characteristic of H+-ATPase-Deficient Mutants of the Lactic Acid BacteriumOenococcus oeni
Authors: Galland Delphine , Tourdot-Maréchal Raphaëlle , Abraham Maud , Chu Ky Son , Guzzo Jean 
Published: April 2003

ABSTRACTThe lack of malolactic activity in H+-ATPase-deficient mutants ofOenococcus oeniselected previously was analyzed at the molecular level. Western blot experiments revealed a spot at 60 kDa corresponding to the malolactic enzyme only in the parental strain. Moreover, themleAtranscript encoding the malolactic enzyme was not detected by reverse transcription (RT)-PCR analysis of mutants. These results suggest that the malolactic operon was not transcribed in ATPase-deficient mutants. ThemleRgene encoding a LysR-type regulatory protein which should be involved in expression of the malolactic genes was described previously forO. oeni. Results obtained in this study show that themleRtranscript was not detected in the mutants by RT-PCR. No mutation in the nucleotide sequences of themleRgene and the malolactic operon was found. The effect of a reduction in H+-ATPase activity onl-malate metabolism was then investigated by using other malolactic bacteria. Spontaneous H+-ATPase-deficient mutant strains ofLactococcus lactisandLeuconostoc mesenteroideswere isolated by using neomycin resistance. Two mutants were selected. These mutants exhibited ATPase activities that were reduced to 54 and 70% of the activities obtained for theL. lactisandL. mesenteroidesparental strains, respectively. These mutants were also acid sensitive. However, in contrast to the ATPase-deficient mutants ofO. oeni, activation ofl-malate metabolism was observed with theL. lactisandL. mesenteroidesmutants under optimal or acidic growth conditions. These data support the suggestion that expression of the genes encoding malolactic enzymes inO. oeniis regulated by themleRproduct, as it is inL. lactis. Nevertheless, our results strongly suggest that there is a difference between the regulation of expression of the malolactic locus inO. oeniand the regulation of expression of this locus in less acidophilic lactic acid bacteria.
Identification of
Lactobacillus reuteri
Genes Specifically Induced in the Mouse Gastrointestinal Tract
Authors: Walter Jens , Heng Nicholas C. K. , Hammes Walter P. , Loach Diane M. , Tannock Gerald W. , Hertel Christian 
Published: April 2003

ABSTRACT

Lactobacilli are common inhabitants of the gastrointestinal tracts of mammals and have received considerable attention due to their putative health-promoting properties. Little is known about the traits that enhance the ability of these bacteria to inhabit the gastrointestinal tract. In this paper we describe the development and application of a strategy based on in vivo expression technology (IVET) that enables detection of
Lactobacillus reuteri
genes specifically induced in the murine gut. A plasmid-based system was constructed containing ′
ermGT
(which confers lincomycin resistance) as the primary reporter gene for selection of promoters active in the gastrointestinal tract of mice treated with lincomycin. A second reporter gene, ′
bglM
(β-glucanase), allowed differentiation between constitutive and in vivo inducible promoters. The system was successfully tested in vitro and in vivo by using a constitutive promoter. Application of the IVET system with chromosomal DNA of
L. reuteri
100-23 and reconstituted lactobacillus-free mice revealed three genes induced specifically during colonization. Two of the sequences showed homology to genes encoding xylose isomerase (
xylA
) and peptide methionine sulfoxide reductase (
msrB
), which are involved in nutrient acquisition and stress responses, respectively. The third locus showed homology to the gene encoding a protein whose function is not known. Our IVET system has the potential to identify genes of lactobacilli that have not previously been functionally characterized but which may be essential for growth of these bacteria in the gastrointestinal ecosystem.
Overproduction of Threonine Aldolase Circumvents the Biosynthetic Role of Pyruvate Decarboxylase in Glucose-Limited Chemostat Cultures ofSaccharomyces cerevisiae
Authors: van Maris Antonius J. A. , Luttik Marijke A. H. , Winkler Aaron A. , van Dijken Johannes P. , Pronk Jack T. 
Published: April 2003

ABSTRACTPyruvate decarboxylase-negative (Pdc−) mutants ofSaccharomyces cerevisiaerequire small amounts of ethanol or acetate to sustain aerobic, glucose-limited growth. This nutritional requirement has been proposed to originate from (i) a need for cytosolic acetyl coenzyme A (acetyl-CoA) for lipid and lysine biosynthesis and (ii) an inability to export mitochondrial acetyl-CoA to the cytosol. To test this hypothesis and to eliminate the C2requirement of Pdc−S. cerevisiae, we attempted to introduce an alternative pathway for the synthesis of cytosolic acetyl-CoA. The addition ofl-carnitine to growth media did not restore growth of a Pdc−strain on glucose, indicating that the C2requirement was not solely due to the inability ofS. cerevisiaeto synthesize this compound. TheS. cerevisiae GLY1gene encodes threonine aldolase (EC 4.1.2.5), which catalyzes the cleavage of threonine to glycine and acetaldehyde. Overexpression ofGLY1enabled a Pdc−strain to grow under conditions of carbon limitation in chemostat cultures on glucose as the sole carbon source, indicating that acetaldehyde formed by threonine aldolase served as a precursor for the synthesis of cytosolic acetyl-CoA. Fractionation studies revealed a cytosolic localization of threonine aldolase. The absence of glycine in these cultures indicates that all glycine produced by threonine aldolase was either dissimilated or assimilated. These results confirm the involvement of pyruvate decarboxylase in cytosolic acetyl-CoA synthesis. The Pdc−GLY1overexpressing strain was still glucose sensitive with respect to growth in batch cultivations. Like any other Pdc−strain, it failed to grow on excess glucose in batch cultures and excreted pyruvate when transferred from glucose limitation to glucose excess.
Gene Encoding the Hydrolase for the Product of the
meta
-Cleavage Reaction in Testosterone Degradation by
Comamonas testosteroni
Authors: Horinouchi Masae , Hayashi Toshiaki , Koshino Hiroyuki , Yamamoto Takako , Kudo Toshiaki 
Published: April 2003

ABSTRACT

In a previous study we isolated the
meta-
cleavage enzyme gene,
tesB
, that encodes an enzyme that carries out a
meta
-cleavage reaction in the breakdown of testosterone by
Comamonas testeroni
TA441 (M. Horinouchi et al., Microbiology 147:3367-3375, 2001). Here we report the isolation of a gene,
tesD
, that encodes a hydrolase which acts on the product of the
meta
-cleavage reaction. We isolated
tesD
by using a Tn
5
mutant of TA441 that showed limited growth on testosterone. TesD exhibited ca. 40% identity in amino acid sequence with BphDs, known hydrolases of biphenyl degradation in
Pseudomonas
spp. The TesD-disrupted mutant showed limited growth on testosterone, and the culture shows an intense yellow color. High-pressure liquid chromatography analysis of the culture of TesD-disrupted mutant incubated with testosterone detected five major intermediate compounds, one of which, showing yellow color under neutral conditions, was considered to be the product of the
meta
-cleavage reaction. The methylation product was analyzed and identified as methyl-4,5-9,10-diseco-3-methoxy-5,9,17-trioxoandrosta-1(10),2-dien-4-oate, indicating that the substrate of TesD in testosterone degradation is 4,5-9,10-diseco-3-hydroxy-5,9,17-trioxoandrosta-1(10),2-dien-4-oic acid. 4,5-9,10-Diseco-3-hydroxy-5,9,17-trioxoandrosta-1(10),2-dien-4-oic acid was transformed by
Escherichia coli-
expressed TesD. Downstream of
tesD
, we identified
tesE
,
F
, and
G
, which encode for enzymes that degrade one of the products of 4,5-9,10-diseco-3-hydroxy-5,9,17-trioxoandrosta-1(10),2-dien-4-oic acid converted by TesD.
Phylogenetic Analysis of Anaerobic Psychrophilic Enrichment Cultures Obtained from a Greenland Glacier Ice Core
Authors: Sheridan Peter P. , Miteva Vanya I. , Brenchley Jean E. 
Published: April 2003

ABSTRACT

The examination of microorganisms in glacial ice cores allows the phylogenetic relationships of organisms frozen for thousands of years to be compared with those of current isolates. We developed a method for aseptically sampling a sediment-containing portion of a Greenland ice core that had remained at −9°C for over 100,000 years. Epifluorescence microscopy and flow cytometry results showed that the ice sample contained over 6 × 10
7
cells/ml. Anaerobic enrichment cultures inoculated with melted ice were grown and maintained at −2°C. Genomic DNA extracted from these enrichments was used for the PCR amplification of 16S rRNA genes with bacterial and archaeal primers and the preparation of clone libraries. Approximately 60 bacterial inserts were screened by restriction endonuclease analysis and grouped into 27 unique restriction fragment length polymorphism types, and 24 representative sequences were compared phylogenetically. Diverse sequences representing major phylogenetic groups including alpha, beta, and gamma
Proteobacteria
as well as relatives of the
Thermus
,
Bacteroides
,
Eubacterium
, and
Clostridium
groups were found. Sixteen clone sequences were closely related to those from known organisms, with four possibly representing new species. Seven sequences may reflect new genera and were most closely related to sequences obtained only by PCR amplification. One sequence was over 12% distant from its closest relative and may represent a novel order or family. These results show that phylogenetically diverse microorganisms have remained viable within the Greenland ice core for at least 100,000 years.
PCR Detection of a Newly Emerged Pandemic
Vibrio parahaemolyticus
O3:K6 Pathogen in Pure Cultures and Seeded Waters from the Gulf of Mexico
Authors: Myers Michael L. , Panicker Gitika , Bej Asim K. 
Published: April 2003

ABSTRACT

This study describes the optimization of PCR parameters and testing of a wide number of microbial species to establish a highly specific and sensitive PCR-based method of detection of a newly emerged pandemic
Vibrio parahaemolyticus
O3:K6 strain in pure cultures and seeded waters from the Gulf of Mexico (gulf water). The selected open reading frame 8 (ORF8) DNA-specific oligonucleotide primers tested were found to specifically amplify all 35 pathogenic
V. parahaemolyticus
O3:K6 pandemic isolates, whereas these primers were not found to detectably amplify two strains of
V. parahaemolyticus
O3:K6 that were isolated prior to the 1996 outbreaks, 122 non-O3:K6 strains of
V. parahaemolyticus
, 198 non-
V.
parahaemolyticus
spp., or 16 non-
Vibrio
bacterial spp. The minimum level of detection by the PCR method was 1 pg of purified genomic DNA or 10
2
ORF8-positive
V. parahaemolyticus
O3:K6 cells in 100 ml of water. The effectiveness of this method for the detection of ORF8-positive isolates in environmental samples was tested in gulf water seeded with 10-fold serial dilutions of this pathogen. A detection level of 10
3
cells per 100 ml of gulf water was achieved. Also, the applicability of this methodology was tested by the detection of this pathogen in gulf water incubated at various temperatures for 28 days. This PCR approach can potentially be used to monitor with high specificity and well within the required range of sensitivity the occurrence and distribution of this newly emerged pathogenic
V. parahaemolyticus
O3:K6 strain in coastal, marine, and ship ballast waters. Early detection of
V. parahaemolyticus
O3:K6 will help increase seafood safety and decrease the risk of infectious outbreaks caused by this pathogen.
Bacterioplankton Community Shifts in an Arctic Lake Correlate with Seasonal Changes in Organic Matter Source
Authors: Crump Byron C. , Kling George W. , Bahr Michele , Hobbie John E. 
Published: April 2003

ABSTRACT

Seasonal shifts in bacterioplankton community composition in Toolik Lake, a tundra lake on the North Slope of Alaska, were related to shifts in the source (terrestrial versus phytoplankton) and lability of dissolved organic matter (DOM). A shift in community composition, measured by denaturing gradient gel electrophoresis (DGGE) of 16S rRNA genes, occurred at 4°C in near-surface waters beneath seasonal ice and snow cover in spring. This shift was associated with an annual peak in bacterial productivity ([
14
C]leucine incorporation) driven by the large influx of labile terrestrial DOM associated with snow meltwater. A second shift occurred after the flux of terrestrial DOM had ended in early summer as ice left the lake and as the phytoplankton community developed. Bacterioplankton communities were composed of persistent populations present throughout the year and transient populations that appeared and disappeared. Most of the transient populations could be divided into those that were advected into the lake with terrestrial DOM in spring and those that grew up from low concentrations during the development of the phytoplankton community in early summer. Sequencing of DNA in DGGE bands demonstrated that most bands represented single ribotypes and that matching bands from different samples represented identical ribotypes. Bacteria were identified as members of globally distributed freshwater phylogenetic clusters within the α- and β-
Proteobacteria
, the
Cytophaga-Flavobacteria-Bacteroides
group, and the
Actinobacteria
.
Virus-Contaminated Oysters: a Three-Month Monitoring of Oysters Imported to Switzerland
Authors: Beuret Christian , Baumgartner Andreas , Schluep Jakob 
Published: April 2003

ABSTRACT
Molluscan shellfish are known to be carriers of viral and bacterial pathogens. The consumption of raw oysters has been repeatedly linked to outbreaks of viral gastroenteritis and hepatitis A. Switzerland imports over 300 tons of oysters per year, 95% of which originate in France. To assess the level of viral contamination, a 3-month monitoring study was conducted. Therefore, the sensitivities of several previously described methods for virus concentration were compared, and one protocol was finally chosen by using dissected digestive tissues. Eighty-seven samples consisting of five oysters each were analyzed for Norwalk-like viruses (NLVs), enteroviruses, and hepatitis A viruses from November 2001 to February 2002. The oysters were exported by 31 French, three Dutch, and two Irish suppliers. Eight oyster samples from six French suppliers were positive for NLVs, and four samples from four French suppliers were positive for enteroviruses; two of the latter samples were positive for both viral agents. No hepatitis A viruses were detected. The sequences of NLV and enterovirus amplicons showed a great variety of strains, especially for the NLVs (strains similar to Bristol, Hawaii, Mexico, and Melksham agent). The data obtained indicated that imported oysters might be a source of NLV infection in Switzerland. However, further studies are needed to determine the quantitative significance of the risk factor within the overall epidemiology of NLVs.
Characterization of TsaR, an Oxygen-Sensitive LysR-Type Regulator for the Degradation ofp-Toluenesulfonate inComamonas testosteroniT-2
Authors: Tralau Tewes , Mampel Jörg , Cook Alasdair M. , Ruff Jürgen 
Published: April 2003

ABSTRACTTsaR is the putative LysR-type regulator of thetsaoperon (tsaMBCD) which encodes the first steps in the degradation ofp-toluenesulfonate (TSA) inComamonas testosteroniT-2. Transposon mutagenesis was used to knock outtsaR. The resulting mutant lacked the ability to grow with TSA andp-toluenecarboxylate (TCA). Reintroduction oftsaRintranson an expression vector reconstituted growth with TSA and TCA. ThetsaRgene was cloned intoEscherichia coliwith a C-terminal His tag and overexpressed as TsaRHis. TsaRHiswas subject to reversible inactivation by oxygen, which markedly influenced the experimental approaches used. Gel filtration showed TsaRHisto be a monomer in solution. Overexpressed TsaRHisbound specifically to three regions within the promoter between the divergently transcribedtsaRandtsaMBCD. The dissociation constant (KD) for the whole promoter region was about 0.9 μM, and the interaction was a function of the concentration of the ligand TSA. A regulatory model for this LysR-type regulator is proposed on the basis of these data.
Heat Shock Response by the Hyperthermophilic Archaeon
Pyrococcus furiosus
Authors: Shockley Keith R. , Ward Donald E. , Chhabra Swapnil R. , Conners Shannon B. , Montero Clemente I. , Kelly Robert M. 
Published: April 2003

ABSTRACT

Collective transcriptional analysis of heat shock response in the hyperthermophilic archaeon
Pyrococcus furiosus
was examined by using a targeted cDNA microarray in conjunction with Northern analyses. Differential gene expression suggests that
P
.
furiosus
relies on a cooperative strategy of rescue (thermosome [Hsp60], small heat shock protein [Hsp20], and two VAT-related chaperones), proteolysis (proteasome), and stabilization (compatible solute formation) to cope with polypeptide processing during thermal stress.
First-Principles Energy Band Calculation for ZnSb2O6 with Trirutile-Type Structure
Authors: Matsushima Shigenori , Tanizaki Takumi , Nakamura Hiroyuki , Nonaka Moriyasu , Arai Masao 
Published: April 2003

Abstract
The electronic structure of ZnSb2O6 is calculated by using the FLAPW method and the DV-Xα method. The valence band with the width of ca. 10.5 eV is roughly classified into the two bands, where O 2p orbitals are dominant and hybridize with Zn 3d and Sb 5s orbitals. On the other hand, the lower conduction band is mainly constructed from Sb 5s orbitals which have large spatial extent. Therefore, ZnSb2O6 crystal is expected to have large electron mobility with doping carriers.
Improvement of the Catalytic Performance of Pd/WO3/ZrO2 in the Selective NO–CH4–O2 Reaction by the Addition of Water Vapor
Authors: Okumura Kazu , Kusakabe Tetsuji , Yasunobu Naoko , Niwa Miki 
Published: April 2003

Abstract
The Pd/WO3/ZrO2 catalyst exhibited activity for the NO–CH4–O2 reaction in the presence of water vapor when WO3 monolayer covered the ZrO2 surface. The selectivity of methane consumption for NO reduction was considerably improved by the addition of 10% of water vapor.
Sonochemical Coreduction Route to Single-Crystalline InSb Dendrites
Authors: Xiong Yujie , Xie Yi , Du Guoan , Liu Xianming , Tian Xiaobo 
Published: April 2003

Abstract
Single-crystalline InSb dendrites were prepared by a sonochemical coreduction route. The result of supplementary experiments shows the experiment was carried out along the coreduction mechanism. It is found that the ultrasonic power, reaction temperature and solvent played crucial roles in the crystallinity and yield of products.
Hydration of Ca A-Type Zeolite and Ca(OH)2
Authors: Uehara Motoki , Sasaki Takahiko 
Published: April 2003

Abstract
The hydration reaction of Ca A-type zeolite and calcium hydroxide was studied. The results revealed that an isostructural material of hydrocalumite (C-A-H) is generated at the early stage of hydration, and following that of strätlingite–vertumnite is generated. Only 0.77 nm of the C-A-H phase was observed at a humidity below 40% while part of the 0.77 nm phase swelled to 0.82 nm at a humidity of 40% or above.
Manufacturing of Activated Carbon Using Furfural Residue as Raw Material
Authors: Wang Yanhua , Noda Kiyoshi , Kagawa Shoji 
Published: April 2003

Abstract
In a series of study, furfural residue that is a kind of waste byproduct was first utilized for manufacturing activated carbon, by self-activation. Pore characteristics and specific surface area of the resulting activated carbon was examined. It is noted that the self-activation with water content contributed mainly to the development of macropore volumes. This shows good trend for adsorption of sulfur dioxide in exhaust gas and other flue gas.
Generation and Behavior of Naphthoyloxyl Radicals in Photocleavage of 1-(Naphthoyloxy)-2-pyridones
Authors: Najiwara Toshihiro , Segawa Katsunori , Sakuragi Hirochika 
Published: April 2003

Abstract
A series of 1- and 2-naphthoyloxyl radicals are generated from photocleavage of 1-(naphthoyloxy)-2-pyridones in acetonitrile. Introduction of a methoxy group in the naphthalene ring stabilized the naphthoyloxyl radicals to prevent decarboxylation completely and reduced remarkably their reactivities of addition to olefins and hydrogen-atom abstraction.
Gas-Phase Bismuth Sulfide Clusters Produced by Gas-Aggregation Source
Authors: Yamada Yasuhiro 
Published: April 2003

Abstract
Bismuth sulfide clusters BixSy were produced using a gas-aggregation source and investigated by time-of-flight mass spectrometry following ionization with a 266-nm YAG laser. Stable bismuth sulfide cluster ions Bi4S10+ and Bi6S11+, as well as Bi2S2+, Bi3S2+, Bi2S6+, Bi3S9+, Bi4S7+, and Bi6S4+, were observed, indicative of the production of stable neutral bismuth sulfide clusters in the gas phase. The cluster structure was predicted by density-functional calculations.