bluuebunny/crossref_metadata_2025_split huggingface dataset:
Methionine adenosyltransferase I/III deficiency: two Korean compound heterozygous siblings with a novel mutation
Authors: Kim S. Z. , Santamaria E. , Jeong T. E. , Levy H. L. , Mato J. M. , Corrales F. J. , Mudd S. H. 
Published: April 2003

AbstractSummary: Two Korean sisters, one detected during neonatal screening, the otherascertained at age 3 years during family screening, have persistent hypermethioninaemia without elevation of plasma tyrosine or severe liver disease.Plasma total homocysteine (tHcy) is mildly elevated, but not so markedly as to establish a diagnosis of homocystinuria due to cystathionine β‐synthase (CBS) deficiency. CBS deficiency was ruled out by the presence of slightly elevatedconcentrations of plasma cystathionine. Although the plasma concentrations of methionine were markedly elevated, plasma S‐adenosylmethionine (AdoMet) was not. This pattern of metabolic abnormalities suggested that the patients have deficient activity of methionine adenosyltransferase (MAT) intheirlivers (MAT I/III deficiency). Molecular genetic studies demonstrate thateach patient is a compound heterozygote for two mutations in MAT1A, the gene that encodes the catalytic subunit that composes MAT I and MAT III: a previously known inactivating G378S point mutation, and a novel W387X truncating mutation. W387X mutant protein, expressed in E. coli and purified, has about 75% of wild‐type activity. Negative subunit interaction between themutant subunits is suggested to explain the hypermethioninaemia of these sisters. They have had normal growth and development and have no mental retardation, neurological abnormalities, or other clinical problems. They are the first individuals of Korean descent proven to have MAT I/III deficiency.
Complex Genetic Disorders: Evaluating When Genetic Research Findings Are Applicable for Genetic Counseling Practice
Authors: Wolpert Chantelle M. , Melvin Elizabeth C. , Speer Marcy C. 
Published: April 2003

AbstractTraditional genetic counseling processes and principles will be extended to a new realm—complex disorders. Although it may seem like a daunting task, understanding the methodologies used to study complex genetic disorders will enable genetic counselors to critically analyze research studies involving complex disorders. In this article, we explain newly evolving methodologies for genetic research, including case‐control studies and transmission disequilibrium testing (TDT). Additionally, a framework is provided for evaluating original research findings and replication studies.
Pathological structure of the kidney from adult mice with mosaic mutation
Authors: Lenartowicz M. , Kowal M. , Buda‐Lewandowska D. , Styrna J. 
Published: April 2003

AbstractSummary: The mosaic (Atp7amo‐ms) is an X‐linked, lethal mutation in mice. In mosaic mutant males, many clinical features characteristic of defective copper metabolism have been observed and they die at the age of 15 days, exhibiting strongsimilarities to the brindled and macular mutants. About 4% of the mutant males live to sexual maturity and some of them are fertile. In this paper, alterationsin the structure of the kidney from adult mutants are described. Owing to an inherited defect of efflux, copper is accumulated in the kidney of the mutants up to a toxic level and this leads to severe damage of the renal cortex. Pathological changes in the kidney mostly affected the structure of the renal corpuscle and renaltubules.
Blood mononuclear cell coenzyme Q10 concentration and mitochondrial respiratory chain succinate cytochrome‐c reductase activity in phenylketonuric patients
Authors: Hargreaves I. P. , Heales S. J. R. , Briddon A. , Land J. M. , Lee P. J. 
Published: April 2003

AbstractSummary: Coenzyme Q10 (CoQ10) serves as an electron carrier within the mitochondrial respiratory chain (MRC), where it is integrally involved in oxidative phosphorylation and consequently ATP production. It has recently been suggested that phenylketonuria (PKU) patients may be susceptible to a CoQ10 deficiency as a consequence of their phenylalanine‐restricted diet, which avoids foods rich in CoQ10 and its precursors. Furthermore, the high phenylalanine level in PKU patients not on dietary restriction may also result in impaired endogenous CoQ10 production, as previous studies have suggested an inhibitory effect of phenylalanine on HMG‐CoA reductase, the rate‐controlling enzyme in CoQ10 biosynthesis. We investigated the effect of both dietary restriction and elevated plasma phenylalanine concentration on blood mononuclear cell CoQ10 concentration and the activity of MRC complex II+III (succinate:cytochrome‐c reductase; an enzyme that relies on endogenous CoQ10) in a PKU patient population. The concentrations of CoQ10 and MRC complex II+III activity were not found to be significantly different between the PKU patients on dietary restriction, PKU patients off dietary restriction and the control group, although plasma phenylalanine levels were markedly different. The results from this investigation suggest that dietary restriction and the elevated plasma phenylalanine levels of PKU patients do not effect mononuclear cell CoQ10 concentration and consequently the activity of complex II+III of the MRC.
A Patient's Perspective on Genetic Counseling and Predictive Testing for Alzheimer's Disease
Authors: Neilson Jane 
Published: April 2003

AbstractThe availability of genetic testing for Alzheimer's disease is anticipated to be widespread in the future. As an individual at risk with a family history of Alzheimer's disease, I discuss why I sought predictive tests and how I would use the information from such tests. I relay what I learned in my genetic counseling session, my response to the counseling process, and steps I have since taken. I discuss life planning, psychological and fear of discrimination issues from a patient's perspective.
Short Report: Plasma pipecolic acid is frequently elevated in non‐peroxisomal disease
Authors: Baas J. C. M. , van de Laar R. , Dorland L. , Duran M. , Berger R. , Poll‐The B. T. , de Koning T. J. 
Published: April 2003

AbstractSummary: We reviewed our data on patients in whom plasma pipecolic acid wasanalysed. Mild to moderate elevations of pipecolic acid were frequently found in non‐peroxisomal disorders and this should be taken into account when interpreting the laboratory data.
Overproduction of
Thermus
sp. Strain T2 β-Galactosidase in
Escherichia coli
and Preparation by Using Tailor-Made Metal Chelate Supports
Authors: Pessela Benevides C. C. , Vian Alejandro , Mateo César , Fernández-Lafuente Roberto , García José L. , Guisán José M. , Carrascosa Alfonso V. 
Published: April 2003

ABSTRACT

A novel thermostable chimeric β-galactosidase was constructed by fusing a poly-His tag to the N-terminal region of the β-galactosidase from
Thermus
sp. strain T2 to facilitate its overexpression in
Escherichia coli
and its purification by immobilized metal-ion affinity chromatography (IMAC). The poly-His tag fusion did not affect the activation, kinetic parameters, and stability of the β-galactosidase. Copper-iminodiacetic acid (Cu-IDA) supports enabled the most rapid adsorption of the His-tagged enzyme, favoring multisubunit interactions, but caused deleterious effects on the enzyme stability. To improve the enzyme purification a selective one-point adsorption was achieved by designing tailor-made low-activated Co-IDA or Ni-IDA supports. The new enzyme was not only useful for industrial purposes but also has become an excellent model to study the purification of large multimeric proteins via selective adsorption on tailor-made IMAC supports.
Effect of Signal Compounds and Incubation Conditions on the Culturability of Freshwater Bacterioplankton
Authors: Bruns Alke , Nübel Ulrich , Cypionka Heribert , Overmann Jörg 
Published: April 2003

ABSTRACT

The effect of signal compounds and of different incubation conditions on the culturability (i.e., the fraction of all cells capable of growth) of natural bacterioplankton from the eutrophic lake Zwischenahner Meer was investigated over a period of 20 months. Numbers of growing cells were determined by the most-probable-number technique in liquid media containing low concentrations (10 μM) of the signal compounds
N
-(oxohexanoyl)-
dl
-homoserine lactone,
N
-(butyryl)-
dl
-homoserine lactone, cyclic AMP (cAMP), or ATP. cAMP was the most effective signal compound, leading to significantly increased cultivation efficiencies of up to 10% of the total bacterial counts. Microautoradiography with [2,8-
3
H]cAMP, combined with fluorescence in situ hybridization, demonstrated that cAMP was taken up by 18% of all cells. The bacterial cAMP uptake systems had a very low

K
m

value of ≤1 nM. Analysis of the cultured bacteria by 16S rRNA gene fingerprinting showed that different bacterial phylotypes were recovered in the presence and in the absence of cAMP. Consequently, the addition of cAMP caused a stimulation of otherwise nonculturable bacteria. Phylogenetically different bacteria were also recovered at different temperatures and oxygen partial pressures. Throughout the study period, mainly members of the β-subclass of the
Proteobacteria
were cultivated. In addition, some members of the
Actinomycetales
were enriched. Quantification by culture-independent fluorescence in situ hybridization demonstrated that β-
Proteobacteria
and
Actinomycetales
also dominated the natural bacterioplankton assemblage. Sequence comparison revealed that two members of the
Actinomycetales
which reached high numbers in the natural bacterioplankton assemblage could actually be enriched by our cultivation approach.
Coupling of Bacterial Endosymbiont and Host Mitochondrial Genomes in the Hydrothermal Vent Clam
Calyptogena magnifica
Authors: Hurtado Luis A. , Mateos Mariana , Lutz Richard A. , Vrijenhoek Robert C. 
Published: April 2003

ABSTRACT

The hydrothermal vent clam
Calyptogena magnifica
(Bivalvia: Vesicomyidae) depends for its nutrition on sulfur-oxidizing symbiotic bacteria housed in its gill tissues. This symbiont is transmitted vertically between generations via the clam's eggs; however, it remains uncertain whether occasionally symbionts are horizontally transmitted or acquired from the environment. If symbionts are transmitted strictly vertically through the egg cytoplasm, inheritance of symbiont lineages should behave as if coupled to the host's maternally inherited mitochondrial DNA. This coupling would be obscured, however, with low rates of horizontal or environmental transfers, the equivalent of recombination between host lineages. Population genetic analyses of
C. magnifica
clams and associated symbionts from eastern Pacific hydrothermal vents clearly supported the hypothesis of strictly maternal cotransmission. Host mitochondrial and symbiont DNA sequences were coupled in a clam population that was polymorphic for both genetic markers. These markers were not similarly coupled with sequence variation at a nuclear gene locus, as expected for a randomly mating sexual population. Phylogenetic analysis of the two cytoplasmic genes also revealed no evidence for recombination. The tight association between vesicomyid clams and their vertically transmitted bacterial endosymbionts is phylogenetically very young (<50 million years) and may serve as a model for the origin and evolution of eukaryotic organelles.
P1 Trisaccharide (Galα1,4Galβ1,4GlcNAc) Synthesis by Enzyme Glycosylation Reactions Using Recombinant
Escherichia coli
Authors: Liu Ziye , Lu Yuquan , Zhang Jianbo , Pardee Keith , Wang Peng George 
Published: April 2003

ABSTRACT

The frequency of
Escherichia coli
infection has lead to concerns over pathogenic bacteria in our food supply and a demand for therapeutics. Glycolipids on gut cells serve as receptors for the Shiga-like toxin produced by
E. coli
. Oligosaccharide moiety analogues of these glycolipids can compete with receptors for the toxin, thus acting as antibacterials. An enzymatic synthesis of the P1 trisaccharide (Galα1,4Galβ1,4GlcNAc), one of the oligosaccharide analogues, was assessed in this study. In the proposed synthetic pathway, UDP-glucose was generated from sucrose with an
Anabaena
sp. sucrose synthase and then converted with an
E. coli
UDP-glucose 4-epimerase to UDP-galactose. Two molecules of galactose were linked to
N
-acetylglucosamine subsequently with a
Helicobacter pylori
β-l,4-galactosyltransferase and a
Neisseria meningitidis
α-1,4-galactosyltransferase to produce one molecule of P1 trisaccharide. The four enzymes were coexpressed in a single genetically engineered
E. coli
strain that was then permeabilized and used to catalyze the enzymatic reaction. P1 trisaccharide was accumulated up to 50 mM (5.4 g in a 200-ml reaction volume), with a 67% yield based on the consumption of
N
-acetylglucosamine. This study provides an efficient approach for the preparative-scale synthesis of P1 trisaccharide with recombinant bacteria.
Horizontal Transfer of
phnAc
Dioxygenase Genes within One of Two Phenotypically and Genotypically Distinctive Naphthalene-Degrading Guilds from Adjacent Soil Environments
Authors: Wilson Mark S. , Herrick James B. , Jeon Che Ok , Hinman David E. , Madsen Eugene L. 
Published: April 2003

ABSTRACT

Several distinct naphthalene dioxygenases have been characterized to date, which provides the opportunity to investigate the ecological significance, relative distribution, and transmission modes of the different analogs. In this study, we showed that a group of naphthalene-degrading isolates from a polycyclic aromatic hydrocarbon (PAH)-contaminated hillside soil were phenotypically and genotypically distinct from naphthalene-degrading organisms isolated from adjacent, more highly contaminated seep sediments. Mineralization of
14
C-labeled naphthalene by soil slurries suggested that the in situ seep community was more acclimated to PAHs than was the in situ hillside community.
phnAc
-like genes were present in diverse naphthalene-degrading isolates cultured from the hillside soil, while
nahAc
-like genes were found only among isolates cultured from the seep sediments. The presence of a highly conserved
nahAc
allele among gram-negative isolates from the coal tar-contaminated seep area provided evidence for in situ horizontal gene transfer and was reported previously (J. B. Herrick, K. G. Stuart-Keil, W. C. Ghiorse, and E. L. Madsen, Appl. Environ. Microbiol.
63:
2330-2337, 1997). Natural horizontal transfer of the
phnAc
sequence was also suggested by a comparison of the
phnAc
and 16S ribosomal DNA sequences of the hillside isolates. Analysis of metabolites produced by cell suspensions and patterns of amplicons produced by PCR analysis suggested both genetic and metabolic diversity among the naphthalene-degrading isolates of the contaminated hillside. These results provide new insights into the distribution, diversity, and transfer of
phnAc
alleles and increase our understanding of the acclimation of microbial communities to pollutants.
Multiplex Reverse Transcription-PCR for Simultaneous Detection of
Beet Necrotic Yellow Vein Virus
,
Beet Soilborne Virus
, and
Beet Virus Q
and Their Vector
Polymyxa betae
KESKIN on Sugar Beet
Authors: Meunier Alexandre , Schmit Jean-François , Stas Arnaud , Kutluk Nazli , Bragard Claude 
Published: April 2003

ABSTRACT

Three soilborne viruses transmitted by
Polymyxa betae
KESKIN in sugar beet have been described:
Beet necrotic yellow vein virus
(BNYVV), the agent of rhizomania,
Beet soilborne virus
(BSBV), and
Beet virus Q
(BVQ). A multiplex reverse transcription-PCR technique was developed to simultaneously detect BNYVV, BSBV, and BVQ, together with their vector,
P. betae
. The detection threshold of the test was up to 128 times greater than that of an enzyme-linked immunosorbent assay. Systematic association of BNYVV with one or two different pomoviruses was observed. BVQ was detected in samples from Belgium, Bulgaria, France, Germany, Hungary, Italy, Sweden, and The Netherlands but not in samples from Turkey.
The PCR assay in the preclinical safety evaluation of nucleic acid medicines
Authors: Haworth R , Pilling A M 
Published: April 2003

The polymerase chain reaction (PCR) is a highly efficient gene amplification procedure which is increasingly being applied to the safety assessment of nucleic acid (NA) medicines such as gene therapies and DNA vaccines. Although clinical experience is limited, a number of potential safety issues exist with these new compounds including toxicity associated with the expression of encoded gene products, autoimmunity due to the induction of anti-DNA antibodies and insertional mutagenesis. PCR enables these questions to be addressed and provides data on mRNA expression, biodistribution and integration. In this review the use of PCR methodologies in the preclinical safety evaluation of NA medicines is discussed. Particular consideration is given to the issues surrounding the use of PCR in regulatory toxicology, including sensitiv-ity requirements, cross-contamination problems, tissue sampling procedures and good laboratory practice (GLP) compliance. In addition, the use of a PCR-based assay to demonstrate the integration of DNA vector into host DNA is described. As the use of PCR in the development of NA medicines will undoubtedly increase over the next few years, it is important that pathologists and toxicologists familiarise themselves with the principles and applications of this technique.
Kinetic Deuterium Isotope Effect in Single-Electron Transfer Occurring from Tributylphosphine to Viologens
Authors: Yasui Shinro , Itoh Kenji , Ohno Atsuyoshi , Tokitoh Norihiro 
Published: April 2003

Abstract
Single electron transfer (SET) takes place from tributylphosphine (1) to 1-methyl-1′-alkyl-4,4′-bipyridinium salts (viologens; 2) in acetonitrile–methanol. Significant kinetic deuterium isotope effect has been observed with respect to hydrogens of a methyl (or an ethyl) substituent in 2. The results are interpreted in terms of SET occurring within a tight encounter complex formed between 1 and 2.
GaCl3-Promoted Ethenylation of Thioester Silyl Enolate and Dienolate with Silylethyne
Authors: Arisawa Mieko , Miyagawa Chie , Yoshimura Satoru , Kido Yoshiyuki , Yamaguchi Masahiko 
Published: April 2003

Abstract
In the presence of GaCl3, silyl enol ethers derived from either S-alkyl or S-aryl thioesters are ethenylated at the α-carbon atom with trimethylsilylethyne in high yields. The reactions of dienolates give α,α-diethenyl thioesters.
Oxidative Ligand Coupling of Tetraarylborates Promoted by Chlorosilane and Molecular Oxygen
Authors: Sakurai Hidehiro , Morimoto Chihiro , Hirao Toshikazu 
Published: April 2003

Abstract
Oxidative ligand coupling of organoborates is promoted by chlorosilane and molecular oxygen. When tetraarylborate compounds are treated with Ph2SiCl2 or PhSiCl3 in acetonitrile under an oxygen atmosphere, the corresponding biaryls are obtained in good yields. Use of unsymmetrical borates results in the selective formation of unsymmetrical biaryls.
Reactivities of Triethylgermylborate in Methanol
Authors: Nanjo Masato , Matsudo Kazuhiko , Mochida Kunio 
Published: April 2003

Abstract
The reactivity of lithium (triethylgermyl)triphenylborate, prepared from unsolvated triethylgermyllithium and triphenylborane, with organic substrates in methanol was investigated. The germylborates reacted with organic halides and acyl halides to give the corresponding germyl-substituted compounds. From the reaction with carbonyl compounds, esters, carboxylic acid, alkenes, and alkynes, germylborates were completely recovered.
1-Aryl-Substituted Cage Molecules ArC(SiMe2SiMe2)3CR: Preparation, Properties, and Application to Liquid Crystalline Compounds
Authors: Shimizu Masaki , Watanabe Kotaro , Nakagawa Hisashi , Becker Torsten , Sugimoto Susumu , Hiyama Tamejiro 
Published: April 2003

Abstract
Phenyl groups were successively introduced at the bridgehead positions of cage compound HC(SiMe2SiMe2)3CH via deprotonation–cyclohexenylation–dehydrogenation. UV absorption spectra of the cage compounds suggested the possibility of electronic interaction between the cage and aromatic moieties. Bromination of the phenylated cage molecule gave a p-bromo derivative that was transformed to liquid crystalline compounds.
Dichloromethane Activation by Chlorochromium(II) Complexes with TpiPr2: Generation of an Electrophilic Cr–Methylene Species without the Action of an External Cl-Abstraction Reagent
Authors: Sugawara Ken-ichiro , Hikichi Shiro , Akita Munetaka 
Published: April 2003

Abstract
Five-coordinated chlorochromium(II) complexes with TpiPr2 activate CH2Cl2 to give a metal–carbene species without the action of an external Cl-abstraction reagent, and the resulting methylene fragment is trapped by nucleophiles such as pyrazole, pyridine and olefin.
Fabrication of Hierarchically Structured Zeolites through Layer-by-Layer Assembly of Zeolite Nanocrystals on Diatom Templates
Authors: Wang Y J , Tang Y , Wang X D , Dong A G , Shan W , Gao Z 
Published: April 2003

Abstract
Zeolites with hierarchical structure were prepared through layer-by-layer electrostatic assembly of zeolite nanocrystals on the diatom substrate. The thickness and composition of the zeolite coatings on the diatom could be readily tailored by varying the number of deposition cycles and the zeolite types used, respectively.
Nondestructive Real-Time Monitoring of the Redox Status in a Potted Plant by Using a Surface-Coil-Type ESR Resonator
Authors: Tada Mika , Shiraishi Takuo , Yokoyama Hidekatsu , Ohya Hiroaki , Ogata Tateaki , Kamada Hitoshi 
Published: April 2003

Abstract
To perform nondestructive real-time monitoring of the redox state in plants against environmental stress, a 700-MHz surface-coil-type ESR resonator was employed and temporal changes in ESR signals of an exogenous nitroxide radical in the leaves of a potted tobacco plant were observed after chilling. ESR signals of the nitroxide radical were barely observed at room temperature, indicating that the nitroxide radical was reduced to the hydroxylamine by reductants in the leaves. Chilling significantly increased the signal-to-noise ratios (S/Ns) of the nitroxide radical in the leaves. Because hydroxylamines are oxidized to nitroxide radicals by oxidants, it is thought that the ESR S/Ns can be used as an index for oxidation in leaves.
Effect of Solvents on the Preparation of Silica-Coated Magnetic Particles
Authors: Wang Hongzhi , Nakamura Hiroyuki , Yao Ken , Maeda Hideaki , Abe Eiichi 
Published: April 2003

Abstract
The influence of solvents on magnetic particles aggregation during silica coating by the Stober method has been studied, and a simple method has been developed to produce well-dispersed silica-coated magnetic particles using methanol.
Reaction Propagation over a Ring Electrode during Self-Sustained Current Oscillations in the Fe/H2SO4 System
Authors: Shiomi Yuka , Karantonis Antonis , Nakabayashi Seiichiro 
Published: April 2003

Abstract
Spatio-temporal propagation of a reaction front along a ring electrode was observed during self-sustained iron dissolution current oscillations. The propagation was strongly related to the periodicity of the system, which depended on the cell geometry.
Preferential Bond Activation of sp3 C–H over sp2 C–H in α,β-Unsaturated Carboxylic Acids by Ruthenium Complex
Authors: Kanaya Susumu , Komine Nobuyuki , Hirano Masafumi , Komiya Sanshiro 
Published: April 2003

Abstract
Reactions of Ru(1,5-cod)(1,3,5-cot) (1)/Pme3 [cod = cyclooctadiene, cot = cyclooctatriene] with propenoic acids (CH2=CH(R)COOH) give unsaturated ruthenalactones Ru[OC(O)C(R)=CH-κ2O,C](Pme3)4 [R = Me (2a), Et (2b), Pr (2c), iPr (2d)]. In contrast, reactions of trans-2-methyl-2-butenoic acid and 2-methylcinnamic acid (R′CH=C(Me)COOH) give Ru[OC(O)C(CH2R′)=CH-κ2O,C](Pme3)4 [R′ = Me (2b), Ph (2e)] as major products, suggesting the preferential activation of the sp3 C–H over sp2 C–H bond on ruthenium(II) center.