bluuebunny/crossref_metadata_2025 huggingface dataset:
Inhibition of the synthesis of glycosphingolipid by a ceramide analogue (PPMP) in the gastrulation of Bufo arenarum
Authors: Aybar Manuel J. , Fuentes Analía , Sánchez Sara S.
Published: July 2002

In the present study the role of glycosphingolipids (GSL) in amphibian development was investigated. We analysed the de novo synthesis of neutral GSL and gangliosides through the initial stages of Bufo arenarum embryo development and their participation during gastrulation using 1-phenyl-2-palmitoyl-3-morpholino-1-propanol (PPMP), a potent inhibitor of glucosylceramide synthase. Ganglioside synthesis began at the blastula stage and reached a maximum during gastrulation (stages 10-12) while neutral GSL synthesis showed a slight gradual increase, the former being quantitatively more significant than the latter. Ganglioside synthesis was reduced by 90% while neutral GSL synthesis was inhibited by 65% when embryos at blastula stage were cultured for 24 h in 20 μM PPMP. The depletion of GSL from amphibian embryos induced an abnormal gastrulation in a dose-dependent manner. We found that PPMP had a pronounced effect on development since no embryos exhibited normal gastrulation; their developmental rate either slowed down or, more often, became totally arrested. Morphological analysis of arrested embryos revealed inhibition of the gastrulation morphogenetic movements. Analysis of mesodermal cell morphology in those embryos showed a severe decrease in the number and complexity of cellular extensions such as filopodia and lamellipodia. Mesodermal cells isolated from PPMP-treated embryos had very low adhesion percentages. Our results suggest that glycosphingolipids participate in Bufo arenarum gastrulation, probably through their involvement in cell adhesion events.
Ultrastructural observations on in vivo fertilisation in the brushtail possum, Trichosurus vulpecula, following PMSG/LH superovulation and artificial insemination
Authors: Jungnickel M.K. , Harman A.J. , Rodger J.C.
Published: July 2002

Information on the dynamics of gamete interaction in marsupials is very limited and not available for any species from the major Australian Order Diprotodontia which includes most of the more familiar animals such as kangaroos, possums and the koala. This study addressed this deficiency by examining the ultrastructure of in vivo fertilised eggs from common brushtail possums (Trichosurus vulpecula). Females were superovulated by treatment with 15 IU PMSG and then 4 mg porcine LH 3 days later, and inseminations were performed 910-13 h after LH) using epididymal spermatozoa. Between 33 and 39 h after LH injection females were killed, reproductive tracts excised and the oviduct ampulla segment flushed for eggs. Three of the six eggs examined were fertilised as judged by the presence of sperm remnants in the cytoplasm. On the basis of these eggs it was found that sperm penetration left a large hole in the zona pellucida (ZP), suggesting that sperm zona penetration occurs primarily by the enzymatic action of acrosomal enzymes. Sperm lying within the perivitelline space were lacking both an outer acrosomal membrane and the associated acrosomal contents, while both these structures were found on sperm embedded within the mucoid layer, which is consistent with induction of the acrosome reaction by binding to the ZP. Once inside the egg cytoplasm, the sperm head travelled only a short distance before chromatin decondensation occurred. Fertilised eggs showed signs of cytoplasmic activation including cytoskeleton association with apparently dividing mitochondria and prominent rough endoplasmic reticulum. Unfertilised eggs appeared to be undergoing degenerative changes and lacked any evidence of activation. This study has demonstrated that superovulation and laparoscopic intravaginal artificial insemination provide a system through which perifertilisation events in the possum and other monovular Australian marsupials can be examined experimentally.
“THE MOST BEAUTIFUL MURDER”: THE TRANSGRESSIVE AESTHETICS OF MURDER IN VICTORIAN STREET BALLADS
Authors: O’Brien Ellen L.
Published: July 2002

To say that this common [criminal] fate was described in the popular press and commented on simply as a piece of police news is, indeed, to fall short of the facts. To say that it was sung and balladed would be more correct; it was expressed in a form quite other than that of the modern press, in a language which one could certainly describe as that of fiction rather than reality, once we have discovered that there is such a thing as a reality of fiction.

—Louis Chevalier, Laboring Classes and Dangerous Classes

SPEAKING OF NINETEENTH-CENTURY FRANCE, Louis Chevalier traces the bourgeoisie’s elision of the working classes with the criminal classes, in which crime becomes either the representation of working class “failure” or “revenge” (396). Chevalier argues that working- class texts “recorded” their acquiescence to and acceptance of “a genuine fraternity of [criminal] fate” when they “described and celebrated [it] in verse” (397). Though a community of fate might inspire collective resistance, popular poetry and ballads, he confirms, reproduced metonymic connections between criminal and worker when “their pity went out to embrace dangerous classes and laboring classes alike. . . . One might almost say [they proclaimed these characteristics] in an identical poetic strain, so strongly was this community of feeling brought out in the relationship between the favorite subjects of working-class songs and the criminal themes of the street ballads, in almost the same words, meters, and tunes” (396) Acquiescence to or reiteration of worker/criminal equations established itself in workers’ views of themselves as “a different, alien and hostile society” (398) in literature that served as an “involuntary and ‘passive’ recording and communication of them” (395). Though I am investigating Victorian England, not nineteenth-century France, and though I regard the street ballads as popular texts which record resistance, not acquiescence, Chevalier’s work usefully articulates the predicament of class-based ideologies about worker and criminal which functioned similarly in Victorian England. More importantly, Chevalier acknowledges the complexity of street ballads as cultural texts..
INTRODUCTION: VICTORIAN STUDIES AND CULTURAL STUDIES
Authors: Williams Carolyn
Published: July 2002

THE IDEA FOR THIS CLUSTER of work had its origins in a session of the 1996 Modern Language Association Convention in Washington, D. C., where the editors of Victorian Literature and Culture organized a panel devoted to the topic at hand: “Victorian Studies and Cultural Studies.” The panel presentations and the post-panel discussion were extremely stimulating, and it was clear that the rich topic wanted further consideration. The following selection of essays, gathered together under this journal’s special feature, the “Editors’ Topic,” is the result. Here, then, are four articles representing a range of practice — though not, by any means, the entire range of practice — in the intersecting fields of Victorian studies and cultural studies. The articles are followed by fourteen forum essays presenting an array of pressing issues, arguments, and sharp opinions centering in the relations — past, present, and potential — between Victorian studies and cultural studies. Three of the following eighteen pieces were presented (and those in shorter, nascent form) at the MLA: Mary Ellis Gibson’s article on Henry Martyn, Jane Eyre, and Missionary Biography, Kristen Leaver’s consideration of Victorian melodrama, and my brief ruminations on the concepts of “discourse” and “genre.” All the rest were commissioned for this issue of Victorian Literature and Culture.
A natural language system for retrieval of captioned images
Authors: ELWORTHY DAVID , ROSE TONY , CLARE AMANDA , KOTCHEFF AARON
Published: July 2002

ANVIL is an information retrieval system using natural language processing techniques,
intended for retrieval of captioned images. It extracts dependency structures from the image
captions and user queries, and then applies a high accuracy matching algorithm which
recursively explores the dependency structures to determine their similarity. A further algorithm
allows additional contextual information to be extracted following a successful match, with
the intention of helping users understand and organise the retrieval results. ANVIL was
developed to high engineering standards, and as well as looking at the research aspects of
the system, we also look at some of the design and development issues. English and Japanese
versions of the system have been developed.
A history of the International Neuropsychological Society:
The early years (1965–1985)
Authors: ROURKE BYRON P. , MURJI SHEMIRA
Published: July 2002

A history of the early years (1965–1985) of
the International Neuropsychological Society (INS) is
presented. Themes than run through these years—such
as the need for an organizational structure, attempts to
make the Society truly international, and the involvement
of the membership, especially, the “younger”
members, in governance—are clearly evident. After
a somewhat shaky start, the Society came of age toward
the end of this formative 20-year period. (JINS,
2000, 6, 491–509.)
From Theory to Application
Authors: Cohen Ronald A.
Published: July 2002

Neuropsychology owes much to the pioneering efforts of
researchers in cognitive psychology. Theory and methods derived
from the cognitive sciences have provided an important foundation
for neuropsychology. The Attention and Performance
series has been at the vanguard of cognitive psychology, both
chronicling major developments in cognitive science that emerged
over the past half century, and catalyzing new directions in
cognitive theory, method, and application. Most students of
psychology can probably recall some time during their undergraduate
or graduate studies, pulling from university library shelves,
one of the earlier volumes of this series, as they prepared
a term paper, thesis, or research project. The 17th volume of
Attention and Performance of this edited series was
the product of the proceedings of the International Association
for the Study of Attention and Performance, held in Haifa, Israel,
30 years after the first edition in 1966. Reviewing the topics
covered in the earlier editions, one is struck by the extent
to which this series has both mirrored current direction and
anticipated shifts in the paradigms of cognitive science.
Impaired skill learning in children with heavy prenatal
alcohol exposure
Authors: LAFORCE ROBERT , HAYWARD SHARON , COX LORI VITALE
Published: July 2002

Global and widespread cognitive and behavioral
dysfunctions have been documented in children with heavy
prenatal alcohol exposure (CHPAE). In addition to further
exploring explicit-memory functioning in this population,
recent investigations have creatively looked into implicit-memory
functions by testing the ability of CHPAE to perform priming
(Mattson & Riley, 1999) or skill-learning (Carmichael
Olson et al., 1998; Sampson et al., 1997) tasks. These
empirical efforts have been supported by recent studies
which have linked prenatal alcohol exposure to disproportionate
volumetric reductions in subcortical structures such as
the basal ganglia (Mattson et al., 1994) and cerebellum
(Cavanagh et al., 1997), two structures that have been
shown to be actively involved in implicit memory (Doyon
et al., 1997, 1998; Heindel et al., 1989; Rauch et al.,
1997). In each case, a profile of preserved implicit and
impaired explicit-memory functioning has emerged. In the
skill-learning domain, for example, participants were required
to complete four blocks of 100 trials of the serial reaction
time (SRT) task in which participants have to press the
button which corresponds to the light that is illuminated,
and in which there is an embedded sequence of ten positions
that is repeatedly presented throughout blocks of trials.
On the latter task, both studies indicated that CHPAE children
tended to have longer mean response times than controls,
but that their learning profile did not differ across the
four blocks of trials.
Ecologic validity in neuropsychological assessment: Prediction
of wayfinding
Authors: NADOLNE MARNIE J. , STRINGER ANTHONY Y.
Published: July 2002

This study compared the ability of clinical and ecologic
simulation measures to predict performance on environment-specific
criterion measures of wayfinding. Thirty-one unilateral stroke
participants comprised the right and left hemisphere groups
(16 patients with left sided and 15 patients with right sided
strokes). Participants completed a battery of clinical tasks
(e.g., traditional paper-and-pencil measures of visualization,
mental rotation, visual memory and spatial orientation), ecologic
simulations (e.g., slide route recall and visualization of a
model town from differing perspectives) and environment specific
criterion tasks (e.g., route recall and directional orientation).
The groups were equivalent in age, sex, education, handedness,
and weeks since stroke. Both ecologic simulation tasks were
found to have fairly good internal consistency and 1 simulation
task was significantly related to real world wayfinding. Of
the clinical tasks, 1 visual memory test was correlated with
a directional orientation criterion task, but none correlated
with route navigation ability. Results are consistent with
literature purporting the benefits of ecologic simulation tasks
as predictors of real world functioning. (JINS, 2001,
7, 675–682.)
The cognitive determinants of performance on the Austin
Maze
Authors: CROWE SIMON F. , BARCLAY LEE , BRENNAN STEVE , FARKAS LINDA , GOULD EMMA , KATCHMARSKY SHARON , VAYDA SAMANTHA
Published: July 2002

This study aimed to investigate which abilities
are measured by the Austin Maze. One hundred and eight
university students were administered a battery of eight
neuropsychological tests including, the Austin Maze, the
Tower of London, the Wisconsin Card Sort Test, Block Design,
the Visual Spatial Learning Test, Digit Span Backwards,
the Brown-Peterson Task and the Wide Range Achievement
Test of Reading. Results indicated that visuospatial ability
and memory both significantly contributed to performance
on the Austin Maze, but differed in the degree to which
they explained the performance depending on which measure
of maze performance was employed. It appears that visuospatial
ability is measured in early trials of the Austin Maze
when individuals are orienting themselves to the path.
In later trials individuals must call upon visuospatial
memory to consolidate the details of the path. Executive
function and working memory were not found to be significantly
implicated in performance on the Austin Maze. (JINS,
1999, 5, 1–9.)
The implication of property rights for joint agriculture–timber productivity in the Brazilian Amazon
Authors: Otsuki Tsunehiro , Hardie Ian W. , Reis Eustáquio J.
Published: July 2002

This paper examines the effects of the Brazilian governments' title granting policies on the efficiency of agricultural and timber production in the Brazilian Amazon. A two-stage procedure is used that combines Data Envelopment Analysis (DEA) and a Tobit regression. Provision of private land titles before 1995 is found to positively affect the technical efficiency of agricultural and joint agriculture–timber production in 1995. Governmental expenditures, including expenditures to secure property rights, also are found to increase technical efficiency in the agricultural industry. The analysis indicates that revenue efficiency can be improved by producing more roundwood and less agricultural product. Land-granting policies may favorably affect environmental conservation by intensifying land use in agriculture, but they also may harm development by discouraging timber production.
Environmental regulation, benefit-cost analysis and the policy environment in less developed countries
Authors: DAVIES ROB
Published: July 2002

The general argument presented by Arrow et al. runs as follows: government regulation might improve on free market outcomes, since markets sometimes misallocate resources. However, the costs of regulations need to be assessed against their presumed benefits. Benefit-cost analysis is a valuable technique for making such an assessment, even though it was developed for the appraisal of physical investment projects. However, since the technique is not perfect, it should not provide the only input into the process, but rather be part of an array of evidence.
Approaches to spatialisation
Authors: MALHAM D. G.
Published: July 2002

This article describes some of the basic principles of acoustics and psychoacoustics related to the spatialisation of sound. It introduces recording and diffusion technologies, including binaural, stereo and surround-sound techniques.
Re: Collaboration Between the NHS and Social Services in the Provision
of Child and Adolescent Mental Health Services
Authors: Withecomb J. L.
Published: July 2002

I am a Consultant Psychiatrist who spends
a large proportion of my time providing
input to non-health settings. This includes
work with the East Sussex Social Service
Secure Facility, the Medway Secure Training
Centre, the Brighton & Hove Youth
Offending Team, Queensdown EBD
School and the East Sussex Special Placements Scheme.

I read Professor Pearce's paper (Pearce,
1999) with interest, but felt that there were
a number of important omissions. I also
felt that the perspective taken on some
areas was itself so ‘medical’ as to be
unhelpful in supporting truly collaborative
work with professionals from a different
background.
Children as Service Evaluators
Authors: Hennessy Eilis
Published: July 2002

In recent years there has been a growing interest in methods of eliciting
children's views on factors influencing their lives. When children's views
are sought it is important that this is done in a developmentally appropriate
manner with instruments whose psychometric properties are known. The
present review describes a variety of methods that have been used to
evaluate children's satisfaction with services in education, paediatrics and
mental health. The majority of the studies used self-completion
questionnaires and provided only limited information on reliability. Means
of establishing reliability and validity in research with children are
discussed, as are the variables that have been found to correlate with child
satisfaction.
Disinventing standard English
Authors: PENNYCOOK ALASTAIR
Published: July 2002

Review of Tony Bex & Richard J. Watts (eds), Standard English: the widening debate. London: Routledge. 1999. Pp. xi + 312. Hardback £50, ISBN 0 415 191629; paperback £15.99, ISBN 0 415 191637.

According to D'Souza (1999) the question of standard English ‘is one of the great, unresolved problems that we are carrying into the twenty-first century’ (p. 271). Why should this question be so important and why so unresolved? And what does the book under review here add to our possible understanding of this issue? There are a number of significant issues here. First, there is the question of definition: what is a standard language? From this follows the ontological question as to whether they actually exist or are merely convenient (or inconvenient) fictions. Are we talking about spoken or written language? And in the global context, there are questions such as whether a global standard of international English exists or is emerging? Or is international intelligibility always a negotiation of possibilities with no obvious standard? And how do the new standard Englishes of Singapore, India, or Hong Kong relate both to all the other forms of English within those countries and to the other regionalized standards as well as the possible international standard? From definitional questions we move on to more political and pedagogical ones: Are standard languages hegemonic forms to be opposed? Are standard languages hegemonic forms to be acquired? Does access to standard language give people greater social and economic mobility, or is this another myth associated with standard languages?
High-Resolution Physical Map and Transcript Identification of a Prostate Cancer Deletion Interval on 8p22
Authors: Arbieva Zarema H. , Banerjee Kumarika , Kim Su Young , Edassery Seby L. , Maniatis Vasilios S. , Horrigan Stephen K. , Westbrook Carol A.
Published: July 2002

A genomic interval of ∼1–1.5 Mb centered at the MSR marker on 8p22 has emerged as a possible site for a tumor suppressor gene, based on high rates of allele loss and the presence of a homozygous deletion found in metastatic prostate cancer. The objective of this study was to prepare a bacterial contig of this interval, integrate the contig with radiation hybrid (RH) databases, and use these resources to identify transcription units that might represent the candidate tumor suppressor genes. Here we present a complete bacterial contig across the interval, which was assembled using 22 published and 17 newly originated STSs. The physical map provides twofold or greater coverage over much of the interval, including 17 BACs, 15 P1s, 2 cosmids, and 1 PAC clone. The position of the selected markers across the interval in relation to the other markers on the larger chromosomal scale was confirmed by RH mapping using the Stanford G3 RH panel. Transcribed units within the deletion region were identified by exon amplification, searching of the Human Transcript Map, placement of unmapped expressed sequence tags (ESTs) from the Radiation Hybrid Database (RHdb), and from other published sources, resulting in the isolation of six unique expressed sequences. The transcript map of the deletion interval now includes two known genes (MSR and N33) and six novel ESTs.

[The sequences described in this paper have been submitted to the GenBank data library under the accession nos.AF126202–AF126212.]
Construction of a High-Resolution 2.5-Mb Transcript Map of the Human 6p21.2–6p21.3 Region Immediately Centromeric of the Major Histocompatibility Complex
Authors: Tripodis Nicos , Palmer Sophie , Phillips Sam , Milne Sarah , Beck Stephan , Ragoussis Jiannis
Published: July 2002

We have constructed a 2.5-Mb physical and transcription map that spans the human 6p21.2–6p21.3 region and includes the centromeric end of the MHC, using a combination of techniques. In total 88 transcription units including exons, cDNAs, and cDNA contigs were characterized and 60 were confidently positioned on the physical map. These include a number of genes encoding nuclear and splicing factors (Ndr kinase, HSU09564, HSRP20); cell cycle, DNA packaging, and apoptosis related [p21, HMGI(Y), BAK]; immune response (CSBP, SAPK4); transcription activators and zinc finger-containing genes (TEF-5, ZNF76); embryogenesis related (Csa-19); cell signaling (DIPP); structural (HSET), and other genes (TULP1, HSPRARD, DEF-6, EO6811,cyclophilin), as well as a number of RP genes and pseudogenes (RPS10, RPS12-like, RPL12-like, RPL35-like). Furthermore, several novel genes (aBr140-like, a G2S-like, a FBN2-like, aZNF-like, and B1/KIAA0229) have been identified, as well as cDNAs and cDNA contigs. The detailed map of the gene content of this chromosomal segment provides a number of candidate genes, which may be involved in several biological processes that have been associated with this region, such as spermatogenesis, development, embryogenesis, and neoplasia. The data provide useful tools for synteny studies between mice and humans, for genome structure analysis, gene density comparisons, and studies of nucleotide composition, of different isochores and Giemsa light and Giemsa dark bands.
Comparative Genome Mapping in the Sequence-based Era: Early Experience with Human Chromosome 7
Authors: Thomas James W. , Summers Tyrone J. , Lee-Lin Shih-Queen , Maduro Valerie V. Braden , Idol Jacquelyn R. , Mastrian Stephen D. , Ryan Joseph F. , Jamison D. Curtis , Green Eric D.
Published: July 2002

The success of the ongoing Human Genome Project has resulted in accelerated plans for completing the human genome sequence and the earlier-than-anticipated initiation of efforts to sequence the mouse genome. As a complement to these efforts, we are utilizing the available human sequence to refine human-mouse comparative maps and to assemble sequence-ready mouse physical maps. Here we describe how the first glimpses of genomic sequence from human chromosome 7 are directly facilitating these activities. Specifically, we are actively enhancing the available human-mouse comparative map by analyzing human chromosome 7 sequence for the presence of orthologs of mapped mouse genes. Such orthologs can then be precisely positioned relative to mapped human STSs and other genes. The chromosome 7 sequence generated to date has allowed us to more than double the number of genes that can be placed on the comparative map. The latter effort reveals that human chromosome 7 is represented by at least 20 orthologous segments of DNA in the mouse genome. A second component of our program involves systematically analyzing the evolving human chromosome 7 sequence for the presence of matching mouse genes and expressed-sequence tags (ESTs). Mouse-specific hybridization probes are designed from such sequences and used to screen a mouse bacterial artificial chromosome (BAC) library, with the resulting data used to assemble BAC contigs based on probe-content data. Nascent contigs are then expanded using probes derived from newly generated BAC-end sequences. This approach produces BAC-based sequence-ready maps that are known to contain a gene(s) and are homologous to segments of the human genome for which sequence is already available. Our ongoing efforts have thus far resulted in the isolation and mapping of >3,800 mouse BACs, which have been assembled into >100 contigs. These contigs include >250 genes and represent ∼40% of the mouse genome that is homologous to human chromosome 7. Together, these approaches illustrate how the availability of genomic sequence directly facilitates studies in comparative genomics and genome evolution.
Regulation of Arabidopsis thaliana (L.) Heynh Arginine Decarboxylase by Potassium Deficiency Stress
Authors: Watson M. B. , Malmberg R. L.
Published: July 2002

Arginine decarboxylase (ARGdc) is the first enzyme in one of the two pathways to putrescine in plants. ARGdc enzyme activity has been shown to be induced by many environmental factors, including potassium deficiency stress. We investigated the mechanism for induction of ARGdc activity during potassium deficiency stress in Arabidopsis thaliana (L.) Heynh. We show that A. thaliana responds to potassium deficiency stress by increasing ARGdc activity by up to 10-fold over unstressed plants with a corresponding increase in putrescine levels of up to 20-fold. Spermidine and spermine levels do not increase proportionately. Northern analysis showed no increase in ARGdc mRNA levels correlated with the increase in ARGdc enzyme activity. Western analysis revealed that there was no difference between ARGdc protein levels in stressed plants compared with controls. The increase in ARGdc enzyme activity due to potassium deficiency stress does not appear to involve changes in mRNA or protein abundance.
Molecular and Biochemical Characterization of Tomato Farnesyl-Protein Transferase
Authors: Schmitt D. , Callan K. , Gruissem W.
Published: July 2002

The prenylation of membrane-associated proteins involved in the regulation of eukaryotic cell growth and signal transduction is critically important for their subcellular localization and biological activity. In contrast to mammalian cells and yeast, however, the function of protein prenylation in plants is not well understood and only a few prenylated proteins have been identified. We partially purified and characterized farnesyl-protein transferase from tomato (Lycopersicon esculentum, LeFTase) to analyze its biochemical and molecular properties. Using Ras- and G[gamma]-specific peptide substrates and competition assays we showed that tomato protein extracts have both farnesyl-protein transferase and geranylgeranyl-protein transferase 1 activities. Compared with the heterologous synthetic peptide substrates, the plant-specific CaaX sequence of the ANJ1 protein is a less efficient substrate for LeFTase in vitro. LeFTase activity profiles and LeFTase β-subunit protein (LeFTB) levels differ significantly in various tissues and are regulated during fruit development. Partially purified LeFTase requires Zn2+ and Mg2+ for enzymatic activity and has an apparent molecular mass of 100 kD. Immunoprecipitation experiments using anti-α-LeFTB antibodies confirmed that LeFTB is a component of LeFTase but not of tomato geranylgeranyl-protein transferase 1. Based on their conserved biochemical activities, we expect that prenyltransferases are likely integrated with the sterol biosynthesis pathway in the control of plant cell growth.
Molecular Characterization of Potato Fumarate Hydratase and Functional Expression in Escherichia coli
Authors: Nast G. , Muller-Rober B.
Published: July 2002

The tricarboxylic acid cycle enzyme fumarase (fumarate hydratase; EC 4.2.1.2) catalyzes the reversible hydration of fumarate to L-malate. We report the molecular cloning of a cDNA (StFum-1) that encodes fumarase from potato (Solanum tuberosum L.). RNA blot analysis demonstrated that StFum-1 is most strongly expressed in flowers, immature leaves, and tubers. The deduced protein contains a typical mitochondrial targeting peptide and has a calculated molecular mass of 50.1 kD (processed form). Potato fumarase complemented a fumarase-deficient Escherichia coli mutation for growth on minimal medium that contains acetate or fumarate as the sole carbon source, indicating that functional plant protein was produced in the bacterium. Antiserum raised against the recombinant plant enzyme recognized a 50-kD protein in wild-type but not in StFum-1 antisense plants, indicating specificity of the immunoreaction. A protein of identical size was also detected in isolated potato tuber mitochondria. Although elevated activity of fumarase was previously reported for guard cells (as compared with mesophyll cells), additional screening and genomic hybridization data reported here do not support the hypothesis that a second fumarase gene is expressed in potato guard cells.
Purification of a Protein Phosphatase from Chloroplast Stroma Capable of Dephosphorylating the Light-Harvesting Complex-II
Authors: Hammer M. F. , Markwell J. , Sarath G.
Published: July 2002

A protein phosphatase was purified from the stroma of Pea (Pisum sativum L.) chloroplasts that is capable of dephosphorylating synthetic phosphopeptides. Following chromatographic purification of greater than 400-fold, two-dimensional electrophoresis indicated that the stromal protein phosphatase is a 29-kD protein. A similar molecular size was determined for the protein-phosphatase activity using gel-permeation chromatography, indicating that the stromal protein phosphatase is probably a monomer. The purified enzyme was able to dephosphorylate synthetic phosphopeptides, which mimic the thylakoid light-harvesting complex-II (LHC-II) N terminus, as well as LHC-II in thylakoid membranes, but did not dephosphorylate the major 64-kD phosphoprotein in the stroma. The stromal protein phosphatase did not discriminate between dephosphorylation of phosphothreonine and phosphoserine residues in synthetic peptide substrates, providing further evidence that this enzyme is distinct from the protein phosphatase localized in thylakoid membranes. The exact physiological role of the stromal protein phosphatase has yet to be determined, but it may function in the dephosphorylation of LHC-II.
Gibberellin Biosynthesis from Gibberellin A12-Aldehyde in Endosperm and Embryos of Marah macrocarpus
Authors: MacMillan J. , Ward D. A. , Phillips A. L. , Sanchez-Beltran M. J. , Gaskin P. , Lange T. , Hedden P.
Published: July 2002

Soluble enzyme preparations from embryos and endosperm of Marah macrocarpus (previously Echinocystis macrocarpa) were incubated with [14C4]gibberellin(GA)12-aldehyde,[14C4]GA12, [14C1] GA9, 2,3-didehydro[14C1]GA9, [14C1]GA20, and [17–13C,3H]GA5. Embryo preparations converted GA12-aldehyde, GA12, and GA9 to GA4 and GA7; 2,3-didehydroGA9 to GA7; GA5 to GA3; and GA20 (incompletely) to GA1 and GA60, but not to GA3. Endosperm preparations converted GA12-aldehyde and GA12 to GA15, GA24, GA25, and GA9, but, unlike embryo preparations, not to GA4 or GA7. However, GA4 and GA7 were formed from GA9 and GA7 was formed from 2,3-didehydroGA9. Metabolism of GA5 to GA3 and GA20 to GA1 was low. 2,3-DidehydroGA9 accumulated when GA9 was incubated with a desalted endosperm preparation. A cDNA clone (M3–8), selected from an embryo-derived cDNA library using a DNA fragment generated by reverse transcriptase polymerase chain reaction, was expressed in Escherichia coli. The fusion protein converted GA12 to GA9 (major) and GA25 (minor); GA53 was metabolized less effectively and only to GA44. Thus, the M3–8 protein is functionally similar to GA 20-oxidases from Arabidopsis thaliana, Spinacia oleracea, and Pisum sativum, but different from that from Cucurbita maxima seeds, to which its amino acid sequence is most closely related. mRNA hybridizing to M3–8 accumulated in embryos and endosperm of M. macrocarpus, but was absent in vegetative tissues.
A Defective Signal Peptide Tethers the floury-2 Zein to the Endoplasmic Reticulum Membrane
Authors: Gillikin J. W. , Zhang F. , Coleman C. E. , Bass H. W. , Larkins B. A. , Boston R. S.
Published: July 2002

The maize (Zea mays L.) floury-2 (fl2) mutation is associated with a general decrease in storage protein synthesis, altered protein body morphology, and the synthesis of a novel 24-kD α--zein storage protein. Unlike storage proteins in normal kernels and the majority of storage proteins in fl2 kernels, the 24-kD α--zein contains a signal peptide that would normally be removed during protein synthesis and processing. The expected processing site of this α--zein reveals a putative mutation alaine->valine (Ala->Val) that is not found at other junctions between signal sequences and mature proteins. To investigate the impact of such a mutation on signal peptide cleavage, we have assayed the 24-kD fl2 α--zein in a co-translational processing system in vitro. Translation of RNA from fl2 kernels or synthetic RNA encoding the fl2 α--zein in the presence of microsomes yielded a 24-kD polypeptide. A normal signal peptide sequence, generated by site-directed mutagenesis, restored the capacity of the RNA to direct synthesis of a properly processed protein in a cell-free system. Both the fl2 α--zein and the fl2 α--zein (Val->Ala) were translocated into the lumen of the endoplasmic reticulum. The processed fl2 α--zein (Val->Ala) was localized in the soluble portion of the microsomes, whereas the fl2 α--zein co-fractionated with the microsomal membranes. By remaining anchored to protein body membranes during endosperm maturation, the fl2 zein may thus constrain storage protein packing and perturb protein body morphology.
Metabolism of Polyamines in Transgenic Cells of Carrot Expressing a Mouse Ornithine Decarboxylase cDNA1
Authors: Andersen Scott E. , Bastola Dhundy R. , Minocha Subhash C.
Published: July 2002

The metabolisms of arginine (Arg), ornithine (Orn), and putrescine were compared in a nontransgenic and a transgenic cell line of carrot (Daucus carota L.) expressing a mouse Orn decarboxylase cDNA. [14C]Arg, [14C]Orn, and [14C]putrescine were fed to cells and their rates of decarboxylation, uptake, metabolism into polyamines, and incorporation into acid-insoluble material were determined. Transgenic cells showed higher decarboxylation rates for labeled Orn than the nontransgenic cells. This was correlated positively with higher amounts of labeled putrescine production from labeled Orn. With labeled Arg, both the transgenic and the nontransgenic cells exhibited similar rates of decarboxylation and conversion into labeled putrescine. When [14C]putrescine was fed, higher rates of degradation were observed in transgenic cells as compared with the nontransgenic cells. It is concluded that (a) increased production of putrescine via the Orn decarboxylase pathway has no compensatory effects on the Arg decarboxylase pathway, and (b) higher rates of putrescine production in the transgenic cells are accompanied by higher rates of putrescine conversion into spermidine and spermine as well as the catabolism of putrescine.
Two Pine Endo-β-1,4-Glucanases Are Associated with Rapidly Growing Reproductive Structures
Authors: Loopstra Carol A. , Mouradov Aidyn , Vivian-Smith Adam , Glassick Tina V. , Gale Beth V. , Southerton Simon G. , Marshall Heidi , Teasdale Robert D.
Published: July 2002

Two cDNA clones encoding endo-β-1,4-glucanases (EGases) were isolated from a radiata pine (Pinus radiata) cDNA library prepared from immature female strobili. The cDNAs PrCel1 (Pinusradiatacellulase 1) and PrCel2 encode proteins 509 and 515 amino acids in length, respectively, including putative signal peptides. Both proteins contain domains conserved in plant and bacterial EGases. The proteins PRCEL1 and PRCEL2 showed strong similarity to each other (76% amino acid identity), and higher similarity to TPP18 (73 and 67%, respectively), an EGase cloned from tomato (Lycopersicon esculentum) pistils, than to any other reported EGases. Northern-blot analyses indicated that both genes displayed a similar pattern of expression. The only significant difference was in the level of expression. In situ hybridizations were used to demonstrate that, within differentiating pine reproductive structures, PrCel1 expression was greatest in microsporangia in pollen strobili and near the developing ovule in the seed strobili. Expression was also found in vegetative tissues, especially in regions experiencing cell elongation, such as the elongating region of root tips. Both proteins have an ability to degrade carboxymethylcellulose in vitro. Genomic-blot analysis indicated the presence of a family of EGase genes in the radiata pine genome, and that PrCel1 and PrCel2 are transcribed from distinct one-copy genes.
Chlorophyll Synthesis in Dark-Grown Pine Primary Needles
Authors: Schoefs Benoı̂t , Franck Fabrice
Published: July 2002

The pigment content of dark-grown primary needles of Pinus jeffreyi L. and Pinus sylvestris L. was determined by high-performance liquid chromatography. The state of protochlorophyllide a and of chlorophylls during dark growth were analyzed by in situ 77 K fluorescence spectroscopy. Both measurements unambiguously demonstrated that pine primary needles are able to synthesize chlorophyll in the dark. Norflurazon strongly inhibited both carotenoid and chlorophyll synthesis. Needles of plants treated with this inhibitor had low chlorophyll content, contained only traces of xanthophylls, and accumulated carotenoid precursors. The first form of chlorophyll detected in young pine needles grown in darkness had an emission maximum at 678 nm. Chlorophyll-protein complexes with in situ spectroscopic properties similar to those of fully green needles (685, 695, and 735 nm) later accumulated in untreated plants, whereas in norflurazon-treated plants the photosystem I emission at 735 nm was completely lacking. To better characterize the light-dependent chlorophyll biosynthetic pathway in pine needles, the 77 K fluorescence properties of in situ protochlorophyllidea spectral forms were studied. Photoactive and nonphotoactive protochlorophyllide a forms with emission properties similar to those reported for dark-grown angiosperms were found, but excitation spectra were substantially red shifted. Because of their lower chlorophyll content, norflurazon-treated plants were used to study the protochlorophyllide a photoreduction process triggered by one light flash. The first stable chlorophyllide photoproduct was a chlorophyllide a form emitting at 688 nm as in angiosperms. Further chlorophyllide a shifts usually observed in angiosperms were not detected. The rapid regeneration of photoactive protochlorophyllide a from nonphotoactive protochlorophyllide after one flash was demonstrated.
Methyl Jasmonate Induces Lauric Acid ω-Hydroxylase Activity and Accumulation of CYP94A1 Transcripts but Does Not Affect Epoxide Hydrolase Activities inVicia sativaSeedlings
Authors: Pinot Franck , Benveniste Irène , Salaün Jean-Pierre , Durst Francis
Published: July 2002

Treatment of etiolated Vicia sativa seedlings by the plant hormone methyl jasmonate (MetJA) led to an increase of cytochrome P450 content. Seedlings that were treated for 48 h in a 1 mm solution of MetJA stimulated ω-hydroxylation of 12:0 (lauric acid) 14-fold compared with the control (153 versus 11 pmol min−1mg−1 protein, respectively). Induction was dose dependent. The increase of activity (2.7-fold) was already detectable after 3 h of treatment. Activity increased as a function of time and reached a steady level after 24 h. Northern-blot analysis revealed that the transcripts coding for CYP94A1, a fatty acid ω-hydroxylase, had already accumulated after 1 h of exposure to MetJA and was maximal between 3 and 6 h. Under the same conditions, a study of the enzymatic hydrolysis of 9,10-epoxystearic acid showed that both microsomal and soluble epoxide hydrolase activities were not affected by MetJA treatment.
Occurrence of Cello-Oligosaccharides in the Apoplast of Auxin-Treated Pea Stems
Authors: Tominaga Rumi , Samejima Masahiro , Sakai Fukumi , Hayashi Takahisa
Published: July 2002

Treatment of pea (Pisum sativum L.) hypocotyl segments with indole-3-butyric acid, which promotes segment elongation, increased the solubilization of both xyloglucan and cello-oligosaccharides in the apoplast of auxin-treated pea stems. The cello-oligosaccharides were isolated from the apoplastic solution with a charcoal/Celite column and were identified as cellobiose, cellotriose, and cellotetraose after subsequent thin-layer chromatography and paper electrophoresis. Cello-oligosaccharides in the apoplastic fraction were monitored using cellobiose dehydrogenase. Both xyloglucan and cello-oligosaccharides appeared to be formed concurrently within 30 min after treatment with the auxin, and the cello-oligosaccharides increased with stem elongation even after 2 h. The total activity of cellulase did not increase for up to 4 h.
Independent Regulation of Flowering by Phytochrome B and Gibberellins in Arabidopsis1
Authors: Blázquez Miguel A. , Weigel Detlef
Published: July 2002

Phytochromes and gibberellins (GAs) coordinately regulate multiple aspects of Arabidopsis development. Phytochrome B (PHYB) promotes seed germination by increasing GA biosynthesis, but inhibits hypocotyl elongation by decreasing the responsiveness to GAs. Later in the life cycle of the plant, PHYB and GAs have opposite effects on flowering. PHYB delays flowering, while GAs promote flowering, particularly under noninductive photoperiods. To learn how PHYB and GAs interact in the control of flowering, we have analyzed the effect of a phyB mutation on flowering time and on the expression of the floral meristem-identity geneLFY(LEAFY). We show that the early flowering caused by phyBcorrelated with an increase in LFY expression, which complements our previous finding that GAs are required for activation of LFY under noninductive photoperiods (M.A. Blázquez, R. Green, O. Nilsson, M.R. Sussman, D. Weigel [1998] Plant Cell 10: 791−800). Since phyB did not change the GA responsiveness of the LFY promoter and suppressed the lack of flowering of severe GA-deficient mutants under short days, we propose that PHYB modulates flowering time at least partially through a GA-independent pathway. Interestingly, the effects of PHYB on flowering do not seem to be mediated by transcriptional up-regulation of genes such as CO (CONSTANS) andFT (Flowering locusT), which are known to mediate the effects of the photoperiod-dependent floral-induction pathway.
Isolation and Characterization of HvNRT2.3and HvNRT2.4, cDNAs Encoding High-Affinity Nitrate Transporters from Roots of Barley
Authors: Vidmar Joseph John , Zhuo Degen , Siddiqi M. Yaeesh , Glass Anthony D.M.
Published: July 2002

Two full-length cDNAs,HvNRT2.3 and HvNRT2.4, were isolated from roots of barley (Hordeum vulgare), using reverse transcriptase-PCR and RACE-PCR. The corresponding polypeptides, consisting of 507 amino acids (molecular masses of 54.6 kD), belong to the major facilitator superfamily (MFS), and are closely related (>87% identity) to those encoded by HvNRT2.1 andHvNRT2.2 (formerly BCH1 andBCH2, respectively) from roots of barley. The latter are considered to encode inducible high-affinity NO3  − transporters (Trueman et al., 1996).HvNRT2 transcripts were undetectable in NO3  −-deprived plants. Following exposure to either NO3  − or NO2  −, transcript abundance and 13NO3  −influx increased to a maximum by 6 to 12 h, then declined inHvNRT2.1, HvNRT2.2, andHvNRT2.3. The pattern of HvNRT2.4transcript abundance was different, remaining high after achieving peak abundance. When external NO3  − concentrations were varied from 0 to 500 μm under steady-state conditions of NO3  − supply,HvNRT2 transcript accumulation and13NO3  − influx were highest in 50 μm NO3  − -grown plants. When NH4  + was provided together with NO3  −, transcript accumulation during the first 2 h was similar to that due to NO3  − alone, but by 4 h the transcript level was significantly reduced. HvNRT2 transcript was undetectable in leaf tissues.
Purification and Characterization of a Novel Pumpkin Short-Chain Acyl-Coenzyme A Oxidase with Structural Similarity to Acyl-Coenzyme A Dehydrogenases
Authors: De Bellis Luigi , Gonzali Silvia , Alpi Amedeo , Hayashi Hiroshi , Hayashi Makoto , Nishimura Mikio
Published: July 2002

A novel pumpkin (Cucurbita  pepo) short-chain acyl-coenzyme A (CoA) oxidase (ACOX) was purified to homogeneity by hydrophobic-interaction, hydroxyapatite, affinity, and anion-exchange chromatography. The purified enzyme is a tetrameric protein, consisting of apparently identical 47-kD subunits. The protein structure of this oxidase differs from other plant and mammalian ACOXs, but is similar to the protein structure of mammalian mitochondrial acyl-CoA dehydrogenase (ACDH) and the recently identified plant mitochondrial ACDH. Subcellular organelle separation by sucrose density gradient centrifugation revealed that the enzyme is localized in glyoxysomes, whereas no immunoreactive bands of similar molecular weight were detected in mitochondrial fractions. The enzyme selectively catalyzes the oxidation of CoA esters of fatty acids with 4 to 10 carbon atoms, and exhibits the highest activity on C-6 fatty acids. Apparently, the enzyme has no activity on CoA esters of branched-chain or dicarboxylic fatty acids. The enzyme is slightly inhibited by high concentrations of substrate and it is not inhibited by Triton X-100 at concentrations up to 0.5% (v/v). The characteristics of this novel ACOX enzyme are discussed in relation to other ACOXs and ACDHs.
Crystal data for triuraniumpentoxide pyrophosphate, U3O5P2O7
Authors: Barten H.
Published: July 2002

U3O5P2O7 is orthorhombic, space group Cmca or C2cb(Aba2), with a = 7.018(2), b = 9.057(1), c = 16.009(3) Å, V = 1017.5(6) Å3, Z = 4, Dx
= 6.318 Mg m− 3. A Nonius Guinier camera and Cu Kα radiation (λ = 1.5418 Å) was used. Indexed powder data are given and compared with previous data. The JCPDS Diffraction File No. for U3O5P2O7 is 34-1984.