bluuebunny/crossref_metadata_2025 huggingface dataset:
PRODUCTION INTENSIFICATION AND REGIONAL SPECIALIZATION
Authors: Nichols Deborah L. , McLaughlin Mary Jane , Benton Maura
Published: July 2002

Although textiles were important commodities in
the Aztec political economy, it is widely held that textile
production did not involve organized workshops. In the
late 1960s, Charlton (1971, 1981) found a concentration
of large spindle whorls at the Aztec city-state capital
of Otumba that he interpreted as remains of a maguey-fiber
workshop. A subsequent survey and surface collections made
by the Otumba Project discovered additional concentrations
of spindle whorls associated with fiber-processing tools
and manufacturing debris that provide substantial evidence
for organized maguey-fiber workshops at Otumba. An unusually
large sample of more than 1,600 spindle whorls was recovered
in surface collections from sites in the Aztec city-state
of Otumba where both small cotton whorls and large maguey
whorls occurred in low densities associated with concentrations
of domestic pottery (and in some cases house-mound remnants).
In the Aztec capital town of Otumba, maguey spindle whorls
were also present in localized dense concentrations within
a restricted area of the site. These concentrations also
included molds for making spindle whorls, “wasters,”
a high density of heavily worn obsidian blades and basalt
scrapers used in fiber production, and obsidian scrapers.
Based on the quantities and types of associated artifacts
we argue that these concentrations represent remains of
Late Aztec maguey-fiber workshops that were household based.
The workshops processed maguey fibers and made maguey spindle
whorls in a range of sizes for spinning thin and thick
threads and cordage. Secondary craft activities in one
workshop included making cotton spindle whorls and some
lapidary and figurine manufacturing. Maguey-fiber processing,
spinning, and, presumably, weaving also took place in rural
villages, but evidence of organized workshops has only
been found at the urban center. The growth of the maguey-fiber
industry at Otumba during the Late Postclassic period was
part of a broader economic trend of production intensification
in the northeastern Basin of Mexico that included xerophytic
plant cultivation and craft specialization.
Algorithms with polynomial interpretation termination proof
Authors: BONFANTE G. , CICHON A. , MARION J.-Y. , TOUZET H.
Published: July 2002

We study the effect of polynomial interpretation termination proofs of deterministic (resp.
non-deterministic) algorithms defined by con uent (resp. non-con uent) rewrite systems over
data structures which include strings, lists and trees, and we classify them according to the
interpretations of the constructors. This leads to the definition of six function classes which
turn out to be exactly the deterministic (resp. non-deterministic) polynomial time, linear
exponential time and linear doubly exponential time computable functions when the class is
based on con uent (resp. non-con uent) rewrite systems. We also obtain a characterisation of
the linear space computable functions. Finally, we demonstrate that functions with exponential
interpretation termination proofs are super-elementary.
On the effectiveness of functional language features: NAS benchmark
FT
Authors: HAMMES J. , SUR S. , BÖHM W.
Published: July 2002

In this paper we investigate the effectiveness of functional language

features when writing

scientific codes. Our programs are written in the purely functional subset
of

Id and executed

on a one node Motorola Monsoon machine, and in Haskell and executed on
a Sparc 2.

In the application we study – the NAS FT benchmark, a three-dimensional

heat equation

solver – it is necessary to target and select one-dimensional sub-arrays

in three-dimensional

arrays. Furthermore, it is important to be able to share computation in
array

definitions. We

compare first order and higher order implementations of this benchmark.
The

higher order

version uses functions to select one-dimensional sub-arrays, or slices,
from a

three-dimensional

object, whereas the first order version creates copies to achieve the same

result. We compare

various representations of a three-dimensional object, and study the effect
of

strictness in

Haskell. We also study the performance of our codes when employing recursive

and iterative

implementations of the one-dimensional FFT, which forms the kernel of this

benchmark. It

turns out that these languages still have quite inefficient implementations,

with respect to

both space and time. For the largest problem we could run (323),

Haskell is 15 times slower

than Fortran and uses three times more space than is absolutely necessary,

whereas Id on

Monsoon uses nine times more cycles than Fortran on the MIPS R3000, and
uses

five times

more space than is absolutely necessary. This code, and others like it,
should

inspire compiler

writers to improve the performance of functional language implementations.
Sexual risk-taking in later life
Authors: Gott C Merryn
Published: July 2002

It is widely acknowledged that ‘rewarding personal and sexual relationships promote health and well-being’, an opinion exemplified by the identification of sexually-transmitted infections (STIs) as one of the key targets for disease reduction in the Health of the Nation White Paper. Indeed, since the advent of the AIDS pandemic in the early 1980s, a substantial body of research has been undertaken in the area of sexual health.
Collective Action by Physicians: Beyond Strikes
Authors: GOOLD SUSAN DORR
Published: July 2002

“Collective action” usually brings to
mind images of picket signs held by laborers striking
for better wages and benefits. Collective action, however,
need not be limited to the withholding of labor. Nor need
it involve only the working or middle classes, as airline
pilots have recently demonstrated. Finally, collective
action need not have as its only purpose the self-interest
of the group. Collective action does, however, always involve
a joining together of individuals united by common goals
or interests in order to consolidate power for the purpose
of negotiating with another group or entity. Examples of
collective action obviously include striking, other withholding
labor actions, and slowdowns, but can also include many
other activities. “Paper strikes,” for example,
have been threatened or used by house officer organizations
in the past. In a paper strike, patient care continues
but without documentation, and thus, the institution suffers
from absent or delayed financial remuneration.
Future Animal: Environmental and Animal Welfare Perspectives
on the Genetic Engineering of Animals
Authors: MUNRO LYLE
Published: July 2002

Genetic engineering is a social invention as much
as a biological one. Ordinary citizens interested in the
well-being of life on the planet should therefore be involved
in the ethical debates concerning the future of nonhuman
animals. The creations of genetic engineers ought to be
evaluated on a case-by-case basis by what the American
philosopher R. G. Frey calls “a jury of concerned
individuals.” Frey is an advocate for putting animals in
perspective, which means that animals matter, but not as much
as humans. He therefore supports the prevailing moral orthodoxy,
which currently in the West means that animals can be eaten,
dissected, hunted, and exhibited, provided that these things
are done humanely and that the benefits to humans outweigh
the harms to the animals. The “concerned individual,”
he suggests, would have no objection to humans killing
animals as long as the animals do not suffer. In the present
paper, my aim is to raise some of the ethical, welfare,
and social issues from an animal-protectionist perspective
which ordinary citizens would need to consider if they
were ever asked to vote on the benefits or otherwise of
the impact of genetic engineering on animal welfare.
Log-Concavity and the Spectral Gap of Stochastic Matrices
Authors: WEINECK EKKEHARD
Published: July 2002

Let Q be a stochastic matrix and I be the identity
matrix. We show by a direct combinatorial
approach that the coefficients of the characteristic polynomial of the
matrix I−Q are log-concave. We use this fact
to prove a new bound for the second-largest eigenvalue of Q.
All the town is a stage: civic ceremonies and religious festivities in Spain during the golden age
Authors: Royo José Antonio Mateos
Published: July 2002

During the sixteenth and seventeenth centuries, Spain's cultural life reached its most glorious stage. This ‘Golden Age’ was distinguished by a great variety of civic ceremonies and religious festivities that were performed in towns and cities. Economic and cultural factors encouraged the development of urban space as a spectacular arena for these rituals. The town became a permanent stage on which the identity of social groups and institutions was displayed. This paper examines the characteristics and development of festivals during this period and also the relative contribution of ‘popular’ and ‘learned’ culture to these celebrations.
Road map for the management of gestational diabetes
Authors: Langer Oded
Published: July 2002

Gestational diabetes mellitus (GDM) is defined as ‘carbohydrate intolerance of variable severity with onset or first recognition during pregnancy’. GDM affects approximately 4–10% of all pregnancies in the United States. Pregnancies complicated by GDM have both short and long term effects on the developing fetus. Studies have shown that elevated levels of glycaemia are associated with increased perinatal mortality. O'Sullivan et al. in his original work, found a four-fold higher rate of perinatal mortality in untreated women with gestational diabetes when compared to women with a normal glucose tolerance test in the same time period. Pettit et al., when studying Pima Indians, found a direct association between a 2-hour, 75g glucose load result and perinatal mortality. Evaluation of recent studies concerning gestational diabetes revealed relatively high rates of stillbirth and perinatal mortality. Thus, it is clear that lack of a therapeutic regimen for these patients will result in increased fetal mortality.
The activity for the induction of the sperm acrosome reaction localises in the outer layers and exists in the high-molecular-weight components of the egg-jelly of the newt, Cynops pyrrhogaster
Authors: Sasaki Takayuki , Kamimura Saori , Takai Hiroyuki , Watanabe Akihiko , Otinake Kazuo
Published: July 2002

Localisation of the acrosome reaction inducing activity in egg-jelly was examined in the newt, Cynops pyrrhogaster. The jelly has six layers: the J0, J1, J2, J3, J4 and st layers. Jelly was mechanically dissected and placed on a Millipore filter. When sperm were added from the outer surface side of the jelly, most of them exhibited the acrosome reaction after passing through the jelly. When egg-jelly was divided into four layers, strong activity for the induction of acrosome reaction was detected in the outer layers, J4+st. These findings suggest that the acrosome reaction is induced by a substance in the outer layers of the egg-jelly. Among jelly components separated by SDS-PAGE, a fraction of more than 500 kDa in molecular weight induced the acrosome reaction. Wheat germ agglutinin (WGA), Griffonia simplicifoliar agglutinin 1 (GS-1), Maclura pomifera agglutinin (MPA) and Arachis hypogaea agglutinin (PNA) inhibited the induction of
the acrosome reaction by jelly extract, and WGA did so in a dose-dependent manner. Those lectins precipitated some molecules of over 500 kDa. These results suggest that the acrosome reaction is induced by the high molecular-weight components of egg-jelly in C. pyrrhogaster.
IN PRAISE OF THEORETICAL NOISE
Authors: Glover David
Published: July 2002

ALTHOUGH IT IS NOW COMMONPLACE to find cultural studies invoked as one of the tributaries of Victorian studies — and the rubric for this journal is no exception — the precise relationship between these two interdiciplinary fields is still unsettled and seems likely to remain so. This is not, as is sometimes claimed, because cultural studies has felt able to dispense with the past, preferring to dwell in and upon the postmodernized present: to the contrary, some of the finest work currently linked to cultural studies has shown a keen awareness of the bankruptcy of contemporary posthistoire, insisting instead upon the continuing need to interrogate the historical record, to reexamine what was at stake both in the longues durées of culturally sedimented time and in the flashpoints and crises of yesteryear. Catherine Hall’s engagement with the changing configuration of “race” in the debates about the British empire between 1830 and 1870 has been exemplary in this regard, but she is far from being the only relevant exception that one might cite — Carolyn Steedman and Richard Johnson are among the many other names that immediately come to mind.
The impact of eastern Australian cut‐off lows on coastal sea levels
Authors: McInnes Kathleen L , Hubbert Graeme D
Published: July 2002

Cut‐off lows that develop off the east coast of Australia are a major cause of elevated coastal sea levels in this region. Their duration often exceeds a day and the combination of elevated sea levels with the high rainfall that commonly accompanies these events means that coastal flooding can be a major hazard. The processes contributing to higher‐than‐normal sea levels are a combination of storm surge and breaking wave setup. Three events are modelled using an atmospheric model, storm surge model and wave setup model. The storm surges resulting from the depressions are found to explain between one‐third and one‐half of the measured sea‐level residuals at the coast and are shown to develop in a regime of coast‐parallel winds that produce onshore Ekman transport. The timing of the storm surges are well captured in two of the events in which the atmospheric depressions are of broad spatial scale and well simulated by the atmospheric model. However, a poor simulation by the atmospheric model of the location of the third low, which is of smaller spatial scale, results in an inaccurate timing of the onset of the surge. The wave setup model produces sea levels at the coast that are around 11% of the incident rms wave heights. The total modelled sea‐level residual, obtained by adding the modelled wave setup to the storm surge, is qualitatively similar to the measured sea‐level residual. However, the modelled values are higher, especially at Sydney where the tide gauge is situated in a sheltered harbour location. In such sheltered locations, it is expected that some attenuation of the wave setup would occur and suggests that sea levels on the open coast could be considerably higher during such events. Copyright © 2001 Royal Meteorological Society
One‐dimensional site‐specific forecasting of radiation fog. Part I: Model formulation and idealised sensitivity studies
Authors: Clark P A , Hopwood W P
Published: July 2002

The Met. Office currently operates a high resolution mesoscale model that provides guidance on the likely formation of radiation fog on the spatial scale of 30–40 km. A project has been under way to build a Site‐Specific Forecast Model (SSFM) using a one‐dimensional version of the Met. Office Unified Model as a basis, with suitable modifications to its surface treatment driven by output from three‐dimensional NWP models. The SSFM has been applied to the forecasting of radiation fog as part of the European Commission sponsored project 4MIDaBLE (4Dimensional Met. Information DataBase Linked across Europe). The first part of this paper describes the model formulation and discusses its behaviour simulating radiation fog in idealised cases and its sensitivity to geostrophic wind speed and initial humidity. In addition to the expected sensitivity to wind and humidity, it has been found that the treatment of surface exchange processes can have a small but significant impact on the formation of fog, its formation and clearance times and its depth. Copyright © 2001 Royal Meteorological Society
A latent heat nudging scheme for the assimilation of precipitation data into an operational mesoscale model
Authors: Jones C D , Macpherson B
Published: July 2002

Surface precipitation‐rate estimates derived from radar data are potentially of considerable value to high‐resolution Numerical Weather Prediction (NWP) models. This paper describes a scheme developed to assimilate precipitation rates derived from the UK weather radar network into the UK Met. Office Mesoscale Model, with the aim of improving the analysis and forecast of precipitation. It is based on ‘latent heat nudging’, in which the model profiles of latent heating are scaled by the ratio of observed and model precipitation rates. This causes the model to adjust so that the diagnosed precipitation rate agrees more closely with observations.

The assimilation algorithm is outlined, and the results of a trial of the scheme are described. The scheme brings an increase in forecast skill for precipitation distribution in the first six to nine hours of the forecast, a conclusion supported both by objective verification against radar data and subjective assessment of 14 forecasts. The main benefit was found to occur in frontal cases. The scheme was implemented operationally on 16 April 1996. Copyright © 1997 Royal Meteorological Society
Photons to Philosophy
Authors: Jernigan Terry L.
Published: July 2002

In less than 150 pages, the author has written
a lucid and broad-ranging primer on functional imaging
with much to offer the neuropsychologist. The book consists
of three sections: “Basic Concepts,” “Three
Methods of Imaging Brain Activation,” and “Establishing
the Correspondence of Activation Patterns to Behavioral
Functions,” with brief Preface and Postscript (“Imaging
Consciousness”). The level of description is more
conceptual than technical, relying more heavily on beautifully
illustrated visual models of the techniques than on more
mathematical accounts, and thus the material is likely
to be easily accessible to clinical and basic neuroscientists
alike. The text should serve well as required reading for
upper division and graduate courses introducing the topic,
and will be a painless and thought-provoking introduction
for scientists in other areas of specialization as well.
Synthesizing Animal and Human Studies of Prenatal Alcohol
Exposure
Authors: Connor Paul D.
Published: July 2002

The primary focus of this volume is on the impact of
alcohol on brain development. It is a perfect example of how
research on both animals and humans can interact to produce
very important findings. In the case of prenatal alcohol exposure,
dialogue between animal and human researchers has proved to
be very profitable for both lines of research. Initial observations
by human researchers identified a syndrome of facial stigmata,
physical malformations, and early behavioral disturbances that
was related to maternal alcohol abuse during pregnancy. They
gave this syndrome the name Fetal Alcohol Syndrome.
However, human researchers were unable to state unequivocally
that prenatal alcohol exposure was teratogenic to the fetus.
Thus, they turned to animal researchers who were able to model
Fetal Alcohol Syndrome in a variety of animals and to confirm
the teratogenicity of alcohol on the developing fetus. The quarter
century of studies of the damage caused by prenatal alcohol
exposure is replete with such interactions between these two
groups of researchers. Without the input and pioneering studies
of animal researchers on the effects of prenatal alcohol exposure,
human researchers would have much less understanding of the
damage caused by alcohol exposure in utero or insights into
possible treatment or remediation strategies for those damaged
by alcohol exposure.
Remote memory for public figures in Alzheimer's disease:
Relationships to regional cortical and limbic brain volumes
Authors: FAMA ROSEMARY , SHEAR PAULA K. , MARSH LAURA , YESAVAGE JEROME A. , TINKLENBERG JARED R. , LIM KELVIN O. , PFEFFERBAUM ADOLF , SULLIVAN EDITH V.
Published: July 2002

This study examined the relationships between regional
cortical and hippocampal brain volumes and components of
remote memory (recall, recognition, sequencing, and photo
naming of presidential candidates) in 13 individuals with
Alzheimer's disease (AD). Recognition and sequencing
of remote memory for public figures were associated with
regional cortical volumes. Specifically, lower
recognition and sequencing scores were associated with
smaller parietal–occipital cortical volumes; poorer
sequencing was also associated with smaller prefrontal
cortical volumes. By contrast, poorer anterograde but not
remote memory scores were correlated with smaller hippocampal
volumes. Within the constraints of the brain regions measured,
these findings highlight the importance of the posterior
cortical areas for selective remote memory processes and
provide support for the dissociation between cortically
mediated remote memory and hippocampally mediated anterograde
memory. (JINS, 2001, 7, 384–390.)
Test–retest bias, reliability, and regression
equations for neuropsychological measures repeated over
a 12–16-week period
Authors: SALINSKY MARTIN C. , STORZBACH DANIEL , DODRILL CARL B. , BINDER LAURENCE M.
Published: July 2002

The interpretation of neurobehavioral change over time
requires knowledge of the test–retest characteristics
of the measures. Without this information it is not possible
to distinguish a true change (i.e., one reflecting the
occurrence or resolution of an intervening process) from
that occurring on the basis of chance or systematic bias.
We tested a group of 72 healthy young to middle aged adults
twice over a 12-to-16-week interval in order to observe
the change in scores over time when there was no known
intervention. The test battery consisted of seven commonly
used cognitive measures and the Profile of Mood States
(POMS). Test–retest regression equations were calculated
for each measure using initial performance, age, education,
and a measure of general intellectual function (Wonderlic
Personnel Test) as regressors. Test–retest correlations
ranged from .39 (POMS Fatigue) to .89 (Digit Symbol). Cognitive
measures generally yielded higher correlations than did
the POMS. Univariate regressions based only on initial
performance adequately predicted retest performance for
the majority of measures. Age and education had a relatively
minor influence. Practice effects and regression to the
mean were common. These test–retest regression equations
can be used to predict retest scores when there has been
no known intervention. They can also be used to generate
statistical statements regarding the significance of change
in an individual's performance over a 12-to-16-week
interval. (JINS, 2001, 7, 597–605.)
A novel efficient algorithm for music transposition
Authors: Lawlor Bob , Fagan A. D.
Published: July 2002

We present a novel efficient algorithm for scaling the frequency content of an audio signal by any desired factor in the range 0.5 (minus one octave) to 2.0 (plus one octave) enabling a recording to be played in any desired key without affecting the tempo. The algorithm uses an adaptive overlap-add (AOLA) technique to realise the desired frequency scaling without affecting the duration. Informal listening tests show output quality equal to that of a conventional overlap-add algorithm used in many commercially available systems, but offering significant computational saving relative to that algorithm. The algorithm can also be used to simultaneously change both the tempo and key of a recording.
EDUCATION SELECTIONEuropean Journal of Special Needs
Education (1999)
Authors: Beveridge Sally , Pearson Sue
Published: July 2002

The three articles from Volume 14 that are
reviewed here are linked by a common
theme: the social interactions of children
with special educational needs. The
countries involved, the target group of
pupils and the methodology vary but each
one draws attention to the complexities of
the social dimension of inclusion and
suggest that physical proximity alone does
not ensure positive social interaction.
An assessment of annual mortality rates in adult‐sized migrant houbara bustards (Chlamydotis [undulata] macqueenii)
Authors: Combreau Olivier , Launay Frédéric , Lawrence Mark
Published: July 2002

Between the years 1994 and 2000, we assessed the mortality rate of adult‐sized, migrant Asian houbara bustards (Chlamydotis [undulata] macqueenii) via banding and satellite tracking programmes. The birds were captured either on their breeding grounds in Kazakhstan (Taukum desert and Buzachi peninsula) and in China (Jungar basin) or on their wintering grounds in Pakistan (Cholistan desert) and in the United Arab Emirates (Baynunah area). For the banding programme, 104 houbara bustards were marked and statistical analysis was performed on the number of transmitters and rings returned by falconers. This allowed us to calculate a 0.045 (SD 0.061) annual mortality rate attributable to hunting activities. The tracking programme analysed the fate of 41 houbara bustards equipped with satellite transmitters (PTTs). Overall, the satellite‐tracked birds were followed for 10,965 days and had travelled all over the distribution range of the species in Asia. The causes of mortality were assessed from the interpretation of the ARGOS data relayed by the sensors embarked on the PTTs. The annual mortality rate was derived from the calculation of the average finite daily survival rate using the Trent & Rongstad (1974) method. With this method, the overall annual mortality rate in adult‐sized houbara bustards migrating through Asia was 0.283 (95%lcl 0.186‐95%ucl 0.404). The hunting and poaching pressure could explain 73.5% of the observed mortality. The mortality rate during winter, when the houbara is under severe hunting pressure, was 11.2 times higher than during the breeding season. Houbara appear to be especially at risk in Pakistan, Afghanistan and Iran. A VORTEX simulation showed that under current hunting and poaching pressures, the probability of extinction of the houbara population modelled can be anticipated at 50 years with a 94% probability. The maximum sustainable yield was estimated at 7.2% of the adult‐sized population whereas as much as 20.8% is currently taken. This work stresses the need for conservationists and Arab falconers to take appropriate concerted measures as soon as possible.
Electrical impedance spectroscopy in relation to seed viability and moisture content in snap bean (Phaseolus vulgaris L.)
Authors: Repo T. , Paine D.H. , Taylor A.G.
Published: July 2002

A method, electrical impedance spectroscopy (EIS), is introduced to study seed viability non-destructively. Snap bean (Phaseolus vulgaris L.) seeds were studied by EIS to determine the most sensitive EIS parameter(s) and the optimal range of moisture content (MC) for separation of viable and non-viable seeds. Hydrated seeds exhibited two impedance arcs in the complex plane at the frequency range from 60 Hz to 8 MHz, and impedance spectra of viable and non-viable seeds differed. The hydrated seeds were best-modelled by an equivalent electrical circuit with two distributed circuit elements in series with a resistor (Voigt model). Moisture content and seed viability had strong effects on the EIS parameters. The most sensitive EIS parameters for detecting the differences between viable and non-viable seeds were the capacitance log(C2), the resistance R2, the resistance ratio R2/R1 and the apex ratio, which all represent specific features of the impedance spectrum. The highest differentiation in the EIS parameters between the viable and non-viable seeds occurred in partially imbibed seeds between MC of 40 and 45% (fresh weight basis).
Antagonism between C/EBPβ and FOG in eosinophil lineage commitment of multipotent hematopoietic progenitors
Authors: Querfurth Erich , Schuster Mikkel , Kulessa Holger , Crispino John D. , Döderlein Gabriele , Orkin Stuart H. , Graf Thomas , Nerlov Claus
Published: July 2002

The commitment of multipotent cells to particular developmental pathways requires specific changes in their transcription factor complement to generate the patterns of gene expression characteristic of specialized cell types. We have studied the role of the GATA cofactor Friend of GATA (FOG) in the differentiation of avian multipotent hematopoietic progenitors. We found that multipotent cells express high levels of FOG mRNA, which were rapidly down-regulated upon their C/EBPβ-mediated commitment to the eosinophil lineage. Expression of FOG in eosinophils led to a loss of eosinophil markers and the acquisition of a multipotent phenotype, and constitutive expression of FOG in multipotent progenitors blocked activation of eosinophil-specific gene expression by C/EBPβ. Our results show that FOG is a repressor of the eosinophil lineage, and that C/EBP-mediated down-regulation of FOG is a critical step in eosinophil lineage commitment. Furthermore, our results indicate that maintenance of a multipotent state in hematopoiesis is achieved through cooperation between FOG and GATA-1. We present a model in which C/EBPβ induces eosinophil differentiation by the coordinate direct activation of eosinophil-specific promoters and the removal of FOG, a promoter of multipotency as well as a repressor of eosinophil gene expression.
Tissue-specific GATA factors are transcriptional effectors of the small GTPase RhoA
Authors: Charron Frédéric , Tsimiklis George , Arcand Mathieu , Robitaille Lynda , Liang Qiangrong , Molkentin Jeffery D. , Meloche Sylvain , Nemer Mona
Published: July 2002

Rho-like GTPases play a pivotal role in the orchestration of changes in the actin cytoskeleton in response to receptor stimulation, and have been implicated in transcriptional activation, cell growth regulation, and oncogenic transformation. Recently, a role for RhoA in the regulation of cardiac contractility and hypertrophic cardiomyocyte growth has been suggested but the mechanisms underlying RhoA function in the heart remain undefined. We now report that transcription factor GATA-4, a key regulator of cardiac genes, is a nuclear mediator of RhoA signaling and is involved in the control of sarcomere assembly in cardiomyocytes. Both RhoA and GATA-4 are essential for sarcomeric reorganization in response to hypertrophic growth stimuli and overexpression of either protein is sufficient to induce sarcomeric reorganization. Consistent with convergence of RhoA and GATA signaling, RhoA potentiates the transcriptional activity of GATA-4 via a p38 MAPK-dependent pathway that phosphorylates GATA-4 activation domains and GATA binding sites mediate RhoA activation of target cardiac promoters. Moreover, a dominant-negative GATA-4 protein abolishes RhoA-induced sarcomere reorganization. The identification of transcription factor GATA-4 as a RhoA mediator in sarcomere reorganization and cardiac gene regulation provides a link between RhoA effects on transcription and cell remodeling.
Chromosome Evolution: The Junction of Mammalian Chromosomes in the Formation of Mouse Chromosome 10
Authors: Pletcher Mathew T. , Roe Bruce A. , Chen Fang , Do Trang , Do Ahn , Malaj Eda , Reeves Roger H.
Published: July 2002

During evolution, chromosomes are rearranged and become fixed into new patterns in new species. The relatively conservative nature of this process supports predictions of the arrangement of ancestral mammalian chromosomes, but the basis for these rearrangements is unknown. Physical mapping of mouse chromosome 10 (MMU 10) previously identified a 380-kb region containing the junction of material represented in human on chromosomes 21 (HSA 21) and 22 (HSA 22) that occurred in the evolutionary lineage of the mouse. Here, acquisition of 275 kb of mouse genomic sequence from this region and comparative sequence analysis with HSA 21 and HSA 22 narrowed the junction from 380 kb to 18 kb. The minimal junction region on MMU 10 contains a variety of repeats, including an L32-like ribosomal element and low-copy sequences found on several mouse chromosomes and represented in the mouse EST database. Sequence level analysis of an interchromosomal rearrangement during evolution has not been reported previously.

[The sequence data described in this paper have been submitted to the GenBank data library under accession nos. AC006507, AC005818, AC005302, AP000215–AP000218,D87009, and AL008723.]
Molecular Characterization of Two Natural Hotspots in the Drosophila buzzatii Genome Induced by Transposon Insertions
Authors: Cáceres Mario , Puig Marta , Ruiz Alfredo
Published: July 2002

Transposable elements (TEs) have been implicated in the generation of genetic rearrangements, but their potential to mediate changes in the organization and architecture of host genomes could be even greater than previously thought. Here, we describe the naturally occurring structural and nucleotide variation around two TE insertions in the genome of Drosophila buzzatii. The studied regions correspond to the breakpoints of a widespread chromosomal inversion generated by ectopic recombination between oppositely oriented copies of a TE namedGalileo. A detailed molecular analysis by Southern hybridization, PCR amplification, and DNA sequencing of 7.1 kb surrounding the inversion breakpoints in 39 D. buzzatii lines revealed an unprecedented degree of restructuring, consisting of 22 insertions of ten previously undescribed TEs, 13 deletions, 1 duplication, and 1 small inversion. All of these alterations occurred exclusively in inverted chromosomes and appear to have accumulated after the insertion of the Galileo elements, within or close to them. The nucleotide variation at the studied regions is six times lower in inverted than in noninverted chromosomes, suggesting that most of the observed changes originated in only 84,000 years.Galileo elements thus seemed to promote the transformation of these, otherwise normal, chromosomal regions in genetically unstable hotspots and highly efficient traps for transposon insertions. The particular features of two new Galileo copies found indicate that this TE belongs to the Foldback family. Together, our results strengthen the importance of TEs, and especially DNA transposons, as inducers of genome plasticity in evolution.

[The sequence data described in this paper have been submitted to the GenBank data library under accession nos.AF368842–AF368859 and AF368861–AF368900. In addition, sequences submitted under accession nos. AF162796–AF162799 were used as a basis for this study.]
Cinnamate-4-Hydroxylase Expression in Arabidopsis (Regulation in Response to Development and the Environment)
Authors: Bell-Lelong D. A. , Cusumano J. C. , Meyer K. , Chapple C.
Published: July 2002

Cinnamate-4-hydroxylase (C4H) is the first Cyt P450-dependent monooxygenase of the phenylpropanoid pathway. To study the expression of this gene in Arabidopsis thaliana, a C4H cDNA clone from the Arabidopsis expressed sequence tag database was identified and used to isolate its corresponding genomic clone. The entire C4H coding sequence plus 2.9 kb of its promoter were isolated on a 5.4-kb HindIII fragment of this cosmid. Inspection of the promoter sequence revealed the presence of a number of putative regulatory motifs previously identified in the promoters of other phenylpropanoid pathway genes. The expression of C4H was analyzed by RNA blot hybridization analysis and in transgenic Arabidopsis carrying a C4H-β-glucuronidase transcriptional fusion. C4H message accumulation was light-dependent, but was detectable even in dark-grown seedlings. Consistent with these data, C4H mRNA was accumulated to light-grown levels in etiolated det1–1 mutant seedlings. C4H is widely expressed in various Arabidopsis tissues, particularly in roots and cells undergoing lignification. The C4H-driven β-glucuronidase expression accurately reflected the tissue-specificity and wound-inducibility of the C4H promoter indicated by RNA blot hybridization analysis. A modest increase in C4H expression was observed in the tt8 mutant of Arabidopsis.
Structure and Blue-Light-Responsive Transcription of a Chloroplast psbD Promoter from Arabidopsis thaliana
Authors: Hoffer P. H. , Christopher D. A.
Published: July 2002

We characterized the effects of light on psbD transcription and mRNA levels during chloroplast development in Arabidopsis thaliana. After 6 to 12 hours of illumination of dark-grown seedlings, two psbD mRNAs were detected and their 5[prime] ends were mapped to positions -550 and -190 bp upstream from the psbD translational start codon. Their kinetics of accumulation resembled the accumulation of chloroplast psbA and rbcL mRNAs but differed from the accumulation of the nuclear-encoded Lhcb and Chs mRNAs. A third psbD mRNA with its 5[prime] end at position -950 accumulated after illumination of > 180 h. The 5[prime] ends of this transcript were mapped to a nucleotide sequence that is highly conserved with functional sequences in the barley (Hordeum vulgare) blue-light-responsive promoter (BLRP). Transcription from the Arabidopsis psbD promoter was 3-fold higher in blue relative to red light, whereas red and blue light affected total chloroplast, rbcL, and 16S rDNA transcription similarly. This study shows that transcription of Arabidopsis psbD is mediated by a BLRP and suggests that psbD genes in other land plants are regulated by a common blue-light-signaling pathway. Isolating the BLRP from Arabidopsis will allow molecular genetic studies aimed at identifying the pertinent photoreceptor and components of this phototransduction pathway.
Identification of Promoter Elements Involved in the Cytosolic Ca2+-Mediated Photoregulation of Maize cab-m1 Expression
Authors: Shiina T. , Nishii A. , Toyoshima Y. , Bogorad L.
Published: July 2002

Changes in cytoplasmic Ca2+ levels are involved in the regulation of several plant genes. However, to our knowledge, no regions of genes or specific cis elements have been shown to be involved in the regulation of plant gene expression by cytosolic Ca2+ signaling. The maize (Zea mays) gene cab-m1, which encodes a light-harvesting chlorophyll a/b-binding apoprotein, is positively photoregulated in mesophyll cells (MC) but not in bundle-sheath cells (BSC). This gene is highly preferentially expressed in maize MC versus BSC. In situ transient expression assays have revealed that exposure of tissues to ethyleneglycol-bis(β-aminoethyl ether)-N,N[prime]-tetraacetic acid (EGTA), which chelates Ca2+, blocks the photostimulation of cab-m1 full promoter (-1026 to +14) activity in MC of leaf segments of dark-grown maize seedlings. EGTA has no effect on expression in BSC. These results suggest that light-induced elevation of the cytosolic Ca2+ concentration in MC is required for the enhancement of cab-m1 expression in MC. Deletion of the sequence from -1026 to -360 completely abolished Ca2+ responsiveness of cab-m1 expression in MC. On the other hand, a 54-bp fragment in the 5[prime] flanking region (-953 to -899 relative to the translation start site) conferred Ca2+ responsiveness on a -359 core promoter:reporter gene, suggesting that Ca2+ signaling is mediated via specific sequences in this short fragment. Furthermore, possible involvement of Ca2+-calmodulin in the signal transduction chain for regulating cab-m1 expression was suggested by the results of inhibitor experiments.
Chlorophyll Breakdown in Senescent Chloroplasts (Cleavage of Pheophorbide a in Two Enzymic Steps)
Authors: Rodoni S. , Muhlecker W. , Anderl M. , Krautler B. , Moser D. , Thomas H. , Matile P. , Hortensteiner S.
Published: July 2002

The cleavage of pheophorbide (Pheide) a into primary fluoescent chlorophyll (Chl) catabolites (pFCCs) in senescent chloroplasts was investigated. Chloroplast preparations isolated from senescent canola (Brassica napus) cotyledons exhibited light-dependent production of pFCC when assay mixtures were supplemented with ferredoxin (Fd). pFCC production in detergent-solubilized membranes was dependent on the presence of an Fd-reducing system. Pheide a cleavage required the action of two proteins, Pheide a oxygenase and a stroma protein. In the absence of stroma protein, Pheide a oxygenase converted Pheide a into a red Chl catabolite (RCC), the presumptive intermediary product of Pheide a cleavage. Incubation of the stroma protein (RCC reductase) together with chemically synthesized RCC resulted in the production of three different FCCs. Two of these catabolites were identical to the pFCCs from canola or barley (Hordeum vulgare) (pFCC-1) and sweet pepper (Capsicum annuum) (pFCC-2), respectively. Thus, the conversion of Pheide a to pFCC could be demonstrated to proceed in two consecutive steps, and both reactions depended on reduced Fd as the source of electrons. The function of Fd in Chl breakdown in vivo is corroborated by the marked retention of this protein until the late stages of senescence, as demonstrated by immunoblotting.
Salinity Promotes Accumulation of 3-Dimethylsulfoniopropionate and Its Precursor S-Methylmethionine in Chloroplasts1
Authors: Trossat Claudine , Rathinasabapathi Bala , Weretilnyk Elizabeth A. , Shen Tun-Li , Huang Zhi-Heng , Gage Douglas A. , Hanson Andrew D.
Published: July 2002

Wollastonia biflora (L.) DC. plants accumulate the osmoprotectant 3-dimethylsulfoniopropionate (DMSP), particularly when salinized. DMSP is known to be synthesized in the chloroplast fromS-methylmethionine (SMM) imported from the cytosol, but the sizes of the chloroplastic and extrachloroplastic pools of these compounds are unknown. We therefore determined DMSP and SMM in mesophyll protoplasts and chloroplasts. Salinization with 30% (v/v) artificial seawater increased protoplast DMSP levels from 4.6 to 6.0 μmol mg−1 chlorophyll (Chl), and chloroplast levels from 0.9 to 1.9 μmol mg−1 Chl. The latter are minimum values because intact chloroplasts leaked DMSP during isolation. Correcting for this leakage, it was estimated that in vivo about one-half of the DMSP is chloroplastic and that stromal DMSP concentrations in control and salinized plants are about 60 and 130 mm, respectively. Such concentrations would contribute significantly to chloroplast osmoregulation and could protect photosynthetic processes from stress injury. SMM levels were measured using a novel mass-spectrometric method. About 40% of the SMM was located in the chloroplast in unsalinized W. biflora plants, as was about 80% in salinized plants; the chloroplastic pool in both cases was approximately 0.1 μmol mg−1 Chl. In contrast, ≥85% of the SMM was extrachloroplastic in pea (Pisum sativum L.) and spinach (Spinacia oleracea L.), which lack DMSP. DMSP synthesis may be associated with enhanced accumulation of SMM in the chloroplast.
Two Isoforms of NADPH:Cytochrome P450 Reductase inArabidopsis thaliana
Authors: Mizutani Masaharu , Ohta Daisaku
Published: July 2002

We have investigated two NADPH-cytochrome (Cyt) P450 reductase isoforms encoded by separate genes (AR1 and AR2) in Arabidopsis thaliana. We isolated AR1 and AR2 cDNAs using a mung bean (Phaseolus aureus L.) NADPH-Cyt P450 reductase cDNA as a probe. The recombinant AR1 and AR2 proteins produced using a baculovirus expression system showed similarKm values for Cyt c and NADPH, respectively. In the reconstitution system with a recombinant cinnamate 4-hydroxylase (CYP73A5), the recombinant AR1 and AR2 proteins gave the same level of cinnamate 4-hydroxylase activity (about 70 nmol min−1 nmol−1 P450). The AR2gene expression was transiently induced by 4- and 3-fold within 1 h of wounding and light treatments, respectively, and the induction time course preceded those of CYP73A5 and a phenylalanine ammonia-lyase (PAL1) gene. On the contrary, the AR1 expression level did not change during the treatments. Analysis of the AR1 andAR2 gene structure revealed that only theAR2 promoter contained three putative sequence motifs (boxes P, A, and L), which are involved in the coordinated expression of CYP73A5 and other phenylpropanoid pathway genes. These results suggest the possibility that AR2transcription may be functionally linked to the induced levels of phenylpropanoid pathway enzymes.
Expression of an Arabidopsis Aspartate Kinase/Homoserine Dehydrogenase Gene Is Metabolically Regulated by Photosynthesis-Related Signals but Not by Nitrogenous Compounds1
Authors: Zhu-Shimoni Judith X. , Galili Gad
Published: July 2002

Although the control of carbon fixation and nitrogen assimilation has been studied in detail, relatively little is known about the regulation of carbon and nitrogen flow into amino acids. In this paper we report our study of the metabolic regulation of expression of an Arabidopsis aspartate kinase/homoserine dehydrogenase (AK/HSD) gene, which encodes two linked key enzymes in the biosynthetic pathway of aspartate family amino acids. Northern blot analyses, as well as expression of chimeric AK/HSD-β-glucuronidase constructs, have shown that the expression of this gene is regulated by the photosynthesis-related metabolites sucrose and phosphate but not by nitrogenous compounds. In addition, analysis of AK/HSD promoter deletions suggested that a CTTGACTCTA sequence, resembling the binding site for the yeast GCN4 transcription factor, is likely to play a functional role in the expression of this gene. Nevertheless, longer promoter fragments, lacking the GCN4-like element, were still able to confer sugar inducibility, implying that the metabolic regulation of this gene is apparently obtained by multiple and redundant promoter sequences. The present and previous studies suggest that the conversion of aspartate into either the storage amino acid asparagine or aspartate family amino acids is subject to a coordinated, reciprocal metabolic control, and this biochemical branch point is a part of a larger, coordinated regulatory mechanism of nitrogen and carbon storage and utilization.
Initial Steps in the Assembly of the Vacuole-Type H+-ATPase1
Authors: Frey Richard K. , Randall Stephen K.
Published: July 2002

The plant vacuole is acidified by a complex multimeric enzyme, the vacuole-type H+-ATPase (V-ATPase). The initial association of ATPase subunits on membranes was studied using an in vitro assembly assay. The V-ATPase assembled onto microsomes when V-ATPase subunits were supplied. However, when the A or B subunit or the proteolipid were supplied individually, only the proteolipid associated with membranes. By using poly(A+) RNA depleted in the B subunit and proteolipid subunit mRNA, we demonstrated A subunit association with membranes at substoichiometric amounts of the B subunit or the 16-kD proteolipid. These data suggest that poly(A+) RNA-encoded proteins are required to catalyze the A subunit membrane assembly. Initial events were further studied by in vivo protein labeling. Consistent with a temporal ordering of V-ATPase assembly, membranes contained only the A subunit at early times; at later times both the A and B subunits were found on the membranes. A large-mass ATPase complex was not efficiently formed in the absence of membranes. Together, these data support a model whereby the A subunit is first assembled onto the membrane, followed by the B subunit.