bluuebunny/crossref_metadata_2025 huggingface dataset:
Special issue on Dependent Type Theory Meets Programming Practice CALL FOR PAPERS
Authors: Barthe Gilles , Dybjer Peter , Thiemann Peter
Published: July 2002

Modern programming languages rely on advanced type systems that detect errors at compile-time.
While the benefits of type systems have long been recognized, there are some areas where
the standard systems in programming languages are not expressive enough. Language designers
usually trade expressiveness for decidability of the type system. Some interesting programs
will always be rejected (despite their semantical soundness) or be assigned uninformative
types.

There are several remedies to this situation. Dependent type systems, which allow the
formation of types that explicitly depend on other types or values, are one of the most
promising approaches. These systems are well-investigated from a theoretical point of view
by logicians and type theorists. For example, dependent types are used in proof assistants to
implement various logics and there are sophisticated proof editors for developing programs
in a dependently typed language.

To the present day, the impact of these developments on practical programming has been
small, partially because of the level of sophistication of these systems and of their type checkers.
Only recently, there have been efforts to integrate dependent systems into intermediate
languages in compilers and programming languages. Additional uses have been identified in
high-profile applications such as mobile code security, where terms of a dependently typed
lambda calculus to encode safety proofs.

A special issue of the Journal of Functional Programming will be devoted to the interplay between
dependent type theory and programming practice. We welcome technical contributions
in the field, as well as position papers that:

[bull ] make researchers in programming languages aware of new developments and research
directions on the theory side;

[bull ] point out to theorists practical uses of advanced type systems and urge them to address
theoretical problems arising in emerging applications.

Authors who are concerned about the appropriateness of a topic are welcome to contact
the guest editors. Manuscripts should be unpublished works and not submitted elsewhere.
Revised and enhanced versions of papers published in conference proceedings that have not
appeared in archival journals are eligible for submission. All submissions will be reviewed
according to the usual standards of scholarship and originality.

Submissions should be sent to Gilles Barthe (Gilles.Barthe@inria.fr), with a copy to
Nasreen Ahmad (nasreen@dcs.gla.ac.uk). Submitted articles should be sent in postscript
format, preferably gzipped and uuencoded. In addition, please send, as plain text, title,
abstract and contact information.

The submission deadline is December 1st, 2001.
Special issue on Algorithmic aspects of functional programming languages
Authors: OKASAKI CHRIS
Published: July 2002

Algorithms can be dramatically affected by the language in which they are implemented.
An algorithm that is elegant and efficient in one language may be ugly
and inefficient in another. If you have ever attempted to implement an assignment-intensive
algorithm in a functional programming language, you are probably more
familiar with this phenomenon than you ever wanted to be! But this sword does not
cut in only one direction. Functional programming languages are wonderfully suited
to expressing certain kinds of algorithms in a clean, modular way, and researchers
over the last five to ten years have greatly expanded the range of algorithms for
which this is true.
EDITORIAL
Authors: PEYTON JONES SIMON , WADLER PHIL
Published: July 2002

In the end, research on functional languages does little good unless
they are used
to write something other than compilers for functional languages. However,
if one
scans a typical functional programming conference or journal, one mainly
sees papers
on twists in language design, speed-ups in compiled code, clever new analyses,
or
refinements to semantic models. It much less common to see a paper that
considers
a functional language as a tool to some other practical end. We would like
to see
this change.

The Journal of Functional Programming carries, and will continue
to carry, articles
on all aspects of functional programming from lambda calculus theory to
language
design to implementation. But we have specially sought, and will continue
to seek,
papers on functional programming practice and experience.

Research and papers on practice and experience sometimes receive less
attention
because they are perceived as possessing less academic content. So we want
to
remind potential authors that we have published a number of papers on this
topic
in the past, and to spell out the criteria we apply to such papers.
A confluent λ-calculus with a catch/throw mechanism
Authors: CROLARD TRISTAN
Published: July 2002

We derive a confluent λ-calculus with a catch/throw mechanism (called λct-calculus) from
Parigot's λμ-calculus. We also present several translations from one calculus into the other
which are morphisms for the reduction. We use them to show that the λct-calculus is a
retract of λμ-calculus (these calculi are isomorphic if we consider only convertibility). As a
by-product, we obtain the subject reduction property for the λct-calculus, as well as the strong
normalization for λct-terms typable in the second order classical natural deduction.
HYLODESMUM, A NEW NAME FOR PODOCARPIUM (LEGUMINOSAE)
Authors: OHASHI H. , MILL R. R.
Published: July 2002

Hylodesmum H. Ohashi & R.R. Mill (Leguminosae or Fabaceae, tribe Desmodieae), based on Desmodium sect. Podocarpium Benth. (=D. subgen. Podocarpium (Benth.) H. Ohashi), is a replacement name proposed here for Podocarpium (Benth.) Y.C. Yang & P.H. Huang published in 1979 for Chinese species belonging to the genus. The name it replaces, Podocarpium (Benth.) Y.C. Yang & P.H. Huang, is a later homonym of two earlier names, Podocarpium A. Braun ex Stizenb. (fossil Leguminosae or Fabaceae) and Podocarpium Unger (fossil Podocarpaceae) and it is also inadmissible under Art. 20.2. New combinations in Hylodesmum are proposed for 14 species and nine infraspecific taxa. A description of the genus is given as well as brief notes on the distribution of each taxon. Shuteria longipes Franch. and Desmodium duclouxii Pamp. are newly regarded as conspecific; the correct name for these in Hylodesmum is H. longipes. Notes on typification are given for several names.
TAXONOMY AND DISTRIBUTION OF EUROPEAN DAMASONIUM(ALISMATACEAE)
Authors: RICH T. C. G. , NICHOLLS-VUILLE F. L.
Published: July 2002

A review of the taxonomy and distribution of the European species of Damasonium Mill. has been carried out to provide background information for conservation. Damasonium alisma Mill., D. bourgaei Coss. and D. polyspermum Coss. are recognized as distinct species, and descriptions and a key are presented. Lectotypes are designated for D. bourgaei and D. polyspermum. Damasonium alisma is the most northerly taxon, predominantly occurring in France and England, but extending eastwards to Russia. Damasonium bourgaei is widespread around the Mediterranean eastwards at least to India. Damasonium polyspermum occurs mainly in the western Mediterranean.
Editors' Introduction
Authors: Dyer Joseph , Harper John
Published: July 2002

Three of the articles in this issue of Plainsong & Medieval Music
were presented at a session devoted to medieval saints' offices
sponsored by the Plainsong and Mediaeval Music Society at the 1999
International Medieval Congress at the University of Leeds. Two of the
papers (Caldwell, Hiley) are devoted to English saints, while a third
(Hankeln) surveys offices, monastic and secular, of the sainted royal
patrons of the diocese of Bamberg, Henry and Kunigunde. Elizabeth
Leach's article on the four-voice balades of Guillaume de Machaut brings
together considerations of transmission, fourteenth-century contrapuntal
theory, and performance practice.

Beginning with this issue of Plainsong & Medieval Music every article
will be preceded by a short abstract. Brief identifications of the
authors, who will most likely be already known to readers in the
relatively small field of medieval music research, will include
their e-mail addresses.
Commentary
Authors: Goodman Kenneth W.
Published: July 2002

To ask whether and to what extent there is an obligation
to treat illegal immigrants implies—just in the
asking—that any duty to treat an illegal resident is
different from or lesser than the duty to treat a citizen.
What could be the reason for thinking that morality affords
fewer benefits or rights to illegal residents?
Keeping Human Rights on the Bioethics Agenda
Authors: d'ORONZIO JOSEPH C.
Published: July 2002

The ideal of universal human rights is arguably
the most potent moral concept marking the modern world.
Its accelerated fruition in the last half of the twentieth
century has created a powerful political force, laying
the groundwork for future generations to extend and apply.
Whereas anything resembling international legal status
for human rights had to wait for the post-Nazi era, the
bold proclamations of the Universal Declaration of Human
Rights (UDHR, 1948) loosened a revolutionary force with
endless potential for application to the full range of
human endeavors. The roots of this movement can be traced
to each and every era in which the vulnerable and powerless
sought justification to oppose arbitrary domination. Its
roots are, therefore, deep and wide.
Response to “This Porridge Is Too Thin” by Gretchen
M. Brown and “Demolishing a ‘Straw Man’”
by Elliott J. Rosen (CQ Vol 7, No 2)
Authors: ACKERMAN FELICIA
Published: July 2002

Each of these hospice officials makes several criticisms
of my paper, “Goldilocks and Mrs. Ilych: A Critical
Look at the ‘Philosophy of Hospice’.”
I will treat these criticisms in turn.
A Catholic Perspective on Access to Healthcare
Authors: McCORMICK RICHARD A.
Published: July 2002

My discussion is presented in three steps: The
present position of the Catholic Church; why it is a relatively
recent tradition; and the roots of the tradition.
Two Steps to Three Choices: A New Approach to Mandated Choice
Authors: HERZ SUSAN E.
Published: July 2002

Approximately 62,000 people in this country await
organ transplants. Ten years ago the waiting list numbered
16,000. The line gets longer every day. Up to 30% of those
waiting in line will die waiting. We face a chronic shortage
of organs. While demand for organs steadily increases, the
number of cadaveric organ donors remains relatively constant:
approximately 4,000 in 1988, and approximately 5,500 in
1997. In response to this environment of scarcity, policymakers
have considered initiatives in a number of domains.
A Large Deviation Inequality for Functions
of Independent, Multi-Way Choices
Authors: GRABLE D. A.
Published: July 2002

Often when analysing randomized algorithms, especially
parallel or distributed algorithms,
one is called upon to show that some function of many
independent choices is tightly
concentrated about its expected value. For example, the
algorithm might colour the
vertices of a given graph with two colours and one would
wish to show that, with high
probability, very nearly half of all edges are monochromatic.

The classic result of Chernoff [3] gives such a
large deviation result when the function
is a sum of independent indicator random variables. The
results of Hoeffding [5] and
Azuma [2] give similar results for functions which
can be expressed as martingales with
a bounded difference property. Roughly speaking, this means
that each individual choice
has a bounded effect on the value of the function. McDiarmid
[9] nicely summarized
these results and gave a host of applications. Expressed a
little differently, his main result is as follows.
On Dominating Sets and Independent Sets of Graphs
Authors: HARANT JOCHEN , PRUCHNEWSKI ANJA , VOIGT MARGIT
Published: July 2002

For a graph G on vertex set V = {1, …, n} let
k = (k1, …, kn)
be an integral vector such that
1 [les ] ki [les ] di for
i ∈ V, where di is the degree of the vertex
i in G. A k-dominating set is a set
Dk ⊆ V such that every vertex
i ∈ V[setmn ]Dk has at least
ki neighbours in Dk. The
k-domination number γk(G) of G
is the cardinality of a smallest k-dominating set of G.

For k1 = · · · = kn = 1,
k-domination corresponds to the usual concept of domination.
Our approach yields an improvement of an upper bound for the domination number found
by N. Alon and J. H. Spencer.

If ki = di for
i = 1, …, n, then the notion of k-dominating set corresponds to the
complement of an independent set. A function fk(p)
is defined, and it will be proved that
γk(G) = min fk(p),
where the minimum is taken over the n-dimensional cube
Cn = {p = (p1, …, pn)
[mid ] pi ∈ ℝ, 0 [les ] pi
[les ] 1, i = 1, …, n}. An
[Oscr ](Δ22Δn-algorithm is presented, where Δ
is the maximum degree of G, with INPUT: p ∈ Cn
and OUTPUT: a k-dominating set Dk of G with
[mid ]Dk[mid ][les ]fk(p).
Introduction to this Special Issue
Authors: OEPEN STEPHAN , FLICKINGER DAN , USZKOREIT HANS , TSUJII JUN-ICHI
Published: July 2002

This issue of Natural Language Engineering journal reports on recent achievements in the
domain of HPSG-based parsing. Research groups at Saarbrücken, CSLI Stanford and the
University of Tokyo have worked on grammar development and processing systems that
allow the use of HPSG-based processing in practical application contexts. Much of the research
reported here has been collaborative, and all of the work shares a commitment to producing
comparable results on wide-coverage grammars with substantial test suites. The focus of this
special issue is deliberately narrow, to allow detailed technical reports on the results obtained
among the collaborating groups. Thus, the volume cannot aim at providing a complete survey
on the current state of the field. This introduction summarizes the research background for the
work reported in the issue, and puts the major new approaches and results into perspective.
Relationships to similar efforts pursued elsewhere are included, along with a brief summary
of the research and development efforts reflected in the volume, the joint reference grammar,
and the common sets of reference data.
An innovative finite state concept for recognition
and parsing of context-free languages
Authors: NEDERHOF M. J. , BERTSCH E.
Published: July 2002

In the full paper in the companion volume, we introduce a new
subclass of the context
free languages, the meta-deterministic languages, which includes the deterministic
languages, but also the languages that result if deterministic languages
are combined via regular expressions.
DO COGNITIVE AND EXPOSURE TREATMENTS IMPROVE VARIOUS PTSD SYMPTOMS DIFFERENTLY? A RANDOMIZED CONTROLLED TRIAL
Authors: Lovell Karina , Marks Isaac M. , Noshirvani Homa , Thrasher Sian , Livanou Maria
Published: July 2002

This study (part of a larger one whose main outcomes were reported by Marks, Lovell, Noshirvani,
Thrasher, & Livanou, 1998) investigated the impact of exposure therapy and cognitive restructuring alone and
combined on the individual symptoms of PTSD and on associated features. Exposure therapy was expected to act mainly
on fear and avoidance, and cognitive restructuring mainly on detachment, restricted range of affect, and associated
features of PTSD. Seventy-seven PTSD outpatients were randomly allocated to one of four treatments: 1) exposure
alone; 2) cognitive restructuring alone; 3) combined exposure and cognitive restructuring; or 4) relaxation (placebo
control). The active treatments were superior to relaxation in improving clusters of PTSD symptoms and associated
features and some but not all individual symptoms and associated features of PTSD. Exposure and cognitive
restructuring improved almost all individual symptoms similarly.
Short-Cuts to Current Thinking in Cognitive Neuroscience
Authors: Leathem Janet
Published: July 2002

From the outset, it should be made clear that this
book is not a new text on cognitive neuroscience. It does
not pretend to cover the whole area comprehensively and
is unsuitable for those wanting a thorough introduction
or overview of cognitive neuroscience with colored illustrations.
Instead, this volume could be considered a companion to
such a text. Findings and Current Opinion in Cognitive
Neuroscience, contains a set of 46 articles carefully
selected from Current Opinion in Neurobiology,
which is part of an even wider series offering current
opinions on a wide range of scientific–medical topics
(e.g., Current Opinion in Neurology and Neurosurgery).
Those who browse in medical or academic libraries will
be familiar with the series, which is unique. Instead of
the traditional journal format, a collection of short review
articles are presented, each written by an expert in the
particular field. Each article summarizes current thinking
in the area or field, and concludes with an annotated bibliography.
Six issues of each set of current opinions are published
annually. Each issue is dedicated to a particular aspect
of an area.
Special Topic II: Economy and Environmental Program for Southeast Asia (EEPSEA)
Authors: GLOVER DAVID
Published: July 2002

The two papers presented here were commissioned by the Economy and Environment Program for Southeast Asia (EEPSEA). Established in 1993, EEPSEA supports training and research in environmental and resource economics. It uses a networking approach to provide financial and technical support to researchers in its ten member countries. The network meets in Singapore in May and November of each year. EEPSEA's current sponsors include Canada (IDRC & CIDA), Sweden (Sida), the MacArthur Foundation, and the Foreign Affairs Ministries of Denmark, Holland, and Norway.
Music technology and audio processing: rall. or accel. into the new millennium?
Authors: Sundberg Johan
Published: July 2002

Music acoustics research can provide support in terms of objective knowledge to further the rapidly developing areas of music technology and audio processing. This is illustrated by three examples taken from current projects at KTH. One concerns the improvement in quality of sound reproduction systems over the last century. A test, where expert listeners rated the year of recordings of different ages, demonstrated that significant advances were made between 1950 and 1970, while development was rather modest before and after this period. The second example investigates the secrets of timbral beauty. Acoustic analyses of recordings of an international opera tenor and a singer with an extremely unpleasant voice shed some light on the basic requirements of good vocal timbre. The unpleasant voice is found to suffer from pressed phonation, lack of a singer's formant, irregular vibrato and insufficient pitch accuracy. The third example elucidates tuning and phrasing differences between deadpan performances of MIDI files played on synthesizers and performances by musicians on real instruments. The examples suggest that future development in the areas of music technology and audio processing may gain considerably from a close interaction with music acoustics research.
Realtime audiovisual rendering and contemporary audiovisual art
Authors: Lokki Tapio , Hiipakka Jarmo , Hänninen Rami , Ilmonen Tommi , Savioja Lauri , Takala Tapio
Published: July 2002

Visual rendering is the process of creating synthetic images of digital models. The

modelling of sound synthesis and propagation in a virtual space is called sound rendering. In

this article we review different audiovisual rendering techniques suitable for realtime

rendering of three-dimensional virtual worlds. Virtual environments are useful

in various application areas, for example in architectural visualisation. With audiovisual

rendering, lighting and acoustics of a modelled concert hall can be experienced

early in the design stage of the building. In this article we demonstrate an

interactive audiovisual rendering system where an animated virtual orchestra plays in

a modelled concert hall. Virtual musicians are conducted by a real conductor

who wears a wired data dress suit and a baton. The conductor and the audience

hear the music rendered according to the acoustics of the virtual concert hall,

creating a lifelike experience.
Case Law Update for 1997 This edition of Points of Law summarises some important
legal decisions made in the courts or reported during 1997.
Authors: Tufnell Guinevere
Published: July 2002

The editor of Points of Law welcomes articles on
topics related to the legal context of work related to
child mental health, news about recent legal
developments (new laws, official codes of practice,
important judicial decisions), commentaries on
these, and suggestions of topics for coverage in
future issues.
Bankers and blue-chippers: an account of - er formations in Present-day English
Authors: Ryder Mary Ellen
Published: July 2002

The nominalizing -er suffix has been extremely productive throughout the history of English, and in Present-day English it has developed a wide range of base and referent types. Yet most formal linguistic treatments account satisfactorily for only a fraction of the types of -er nominals actually found. I propose a cognitive model which not only addresses the problems with verb-based forms that are encountered in other models, but includes an account of all the nonverb-based -er nominals as well.
Japan's Multimember SNTV System and Strategic Voting: The ‘M + 1 Rule’ and Beyond
Authors: Fournier Patrick , Kohno Masaru
Published: July 2002

Since the early 1990s, Steven Reed and Gary Cox have changed our understanding of Japan's multimember SNTV electoral system, by highlighting its institutional effects similar to what is known as Duverger's law in the Anglo-American context. While we offer some additional evidence to consolidate their findings, we also address an issue left unexplored in these studies, namely the role of partisan information. Under Japan's system, party labels matter in elections. We show that, while Japanese voters are generally willing to abandon the candidates without affiliation with established parties, the partisan effects produce constraints for strategic coordination.
Comparative DNA Sequence Analysis of Mouse and Human Protocadherin Gene Clusters
Authors: Wu Qiang , Zhang Theresa , Cheng Jan-Fang , Kim Youngwook , Grimwood Jane , Schmutz Jeremy , Dickson Mark , Noonan James P. , Zhang Michael Q. , Myers Richard M. , Maniatis Tom
Published: July 2002

The genomic organization of the human protocadherin α, β, and γ gene clusters (designated Pcdhα [gene symbol PCDHA], Pcdhβ [PCDHB], and Pcdhγ [PCDHG]) is remarkably similar to that of immunoglobulin and T-cell receptor genes. The extracellular and transmembrane domains of each protocadherin protein are encoded by an unusually large “variable” region exon, while the intracellular domains are encoded by three small “constant” region exons located downstream from a tandem array of variable region exons. Here we report the results of a comparative DNA sequence analysis of the orthologous human (750 kb) and mouse (900 kb) protocadherin gene clusters. The organization of Pcdhα andPcdhγ gene clusters in the two species is virtually identical, whereas the mouse Pcdhβ gene cluster is larger and contains more genes than the human Pcdhβ gene cluster. We identified conserved DNA sequences upstream of the variable region exons, and found that these sequences are more conserved between orthologs than between paralogs. Within this region, there is a highly conserved DNA sequence motif located at about the same position upstream of the translation start codon of each variable region exon. In addition, the variable region of each gene cluster contains a rich array of CpG islands, whose location corresponds to the position of each variable region exon. These observations are consistent with the proposal that the expression of each variable region exon is regulated by a distinct promoter, which is highly conserved between orthologous variable region exons in mouse and human.

[The sequence data described in this paper have been submitted to the GenBank/EMBL/DDBJ data library under accession nos. AY013756–AY013813,AY013873–AY013878, AF332005, and AF332006.]
Reduced Na+ Uptake in the NaCl-Hypersensitive sos1 Mutant of Arabidopsis thaliana
Authors: Ding L. , Zhu J. K.
Published: July 2002

sos1 is an Arabidopsis thaliana mutant with>20 times higher sensitivity toward Na+ inhibition due to a defective high-affinity potassium-uptake system. We report here that sos1 accumulates less Na+ than the wild type in response to NaCl stress. The Na+ contents in sos1 seedlings exposed to 25 mM NaCl for 2 or more d are about 43% lower than those in the wild type. When assayed at 20 mM external NaCl, sos1 seedlings pretreated with low potassium have 32% lower Na+ uptake than the wild type. However, little difference in Na+ uptake could be measured when the seedlings were not pretreated with low potassium. Low-potassium treatment was shown to induce high-affinity potassium-uptake activity in Arabidopsis seedlings. No substantial difference in Na+ efflux between sos1 and the wild type was detected. The results show that the reduced Na+ accumulation in sos1 is due to a lower Na+ influx rate. Therefore, the sos1 mutation appears to disrupt low-affinity Na+ uptake in addition to its impairment of high-affinity K+ uptake.
A Nitrate-Inducible Ferredoxin in Maize Roots (Genomic Organization and Differential Expression of Two Nonphotosynthetic Ferredoxin Isoproteins)
Authors: Matsumura T. , Sakakibara H. , Nakano R. , Kimata Y. , Sugiyama T. , Hase T.
Published: July 2002

We have identified and characterized a nitrate-inducible ferredoxin (Fd) in maize (Zea mays L.) roots by structural analysis of the purified protein and by cloning of its cDNA and gene. In maize Fd isoproteins are encoded by a small multigene family, and the nitrate-inducible Fd was identified as a novel isoprotein, designated Fd VI, which differed from any Fd I to Fd V identified to date. In the roots of seedlings cultured without nitrate, Fd VI was undetectable. However, during the induction of the capacity for nitrate assimilation, the amount of Fd VI increased markedly within 24 h. Concurrently, the level of transcript for Fd VI increased, but more quickly, reaching a maximal level within 2 h with kinetics similar to those of nitrite reductase and Fd-NADP+ reductase. Fd III was constitutively expressed in roots, and no such changes at the protein and mRNA levels were observed during the nitrate induction. In the 5[prime] flanking region of the gene for Fd VI only, we identified NIT-2 motifs, which are widely found in genes for enzymes related to nitrogen metabolism. These data indicate that Fd VI is co-induced with the previously characterized enzymes involved in nitrate assimilation, and they suggest that the novel Fd isoprotein, distinct from the constitutively expressed Fd, might play an important role as an electron carrier from NADPH to nitrite reductase and other Fd-dependent enzymes in root plastids.
L-Ascorbic Acid Metabolism in the Ascorbate-Deficient Arabidopsis Mutant vtc1
Authors: Conklin P. L. , Pallanca J. E. , Last R. L. , Smirnoff N.
Published: July 2002

The biosynthesis of L-ascorbic acid (vitamin C) is not well understood in plants. The ozone-sensitive Arabidopsis thaliana mutant vitamin c-1 (vtc1; formerly known as soz1) is deficient in ascorbic acid, accumulating approximately 30% of wild-type levels. This deficiency could result from elevated catabolism or decreased biosynthesis. No differences that could account for the deficiency were found in the activities of enzymes that catalyze the oxidation or reduction of ascorbic acid. The absolute rate of ascorbic acid turnover is actually less in vtc1 than in wild type; however, the turnover rate relative to the pool of ascorbic acid is not significantly different. The results from [U-14C]Glc labeling experiments suggest that the deficiency is the result of a biosynthetic defect: less L-[14C]ascorbic acid as a percentage of total soluble 14C accumulates in vtc1 than in wild type. The feeding of two putative biosynthetic intermediates, D-glucosone and L-sorbosone, had no positive effect on ascorbic acid levels in either genotype. The vtc1 defect does not appear to be the result of a deficiency in L-galactono-1,4-lactone dehydrogenase, an enzyme able to convert L-galactono-1,4-lactone to ascorbic acid.
Reduction of Light-Induced Anthocyanin Accumulation in Inoculated Sorghum Mesocotyls1
Authors: Lo Sze-Chung Clive , Nicholson Ralph L.
Published: July 2002

Sorghum (Sorghum bicolor L. Moench) accumulates the anthocyanin cyanidin 3-dimalonyl glucoside in etiolated mesocotyls in response to light. Inoculation with the nonpathogenic fungus Cochliobolus heterostrophus drastically reduced the light-induced accumulation of anthocyanin by repressing the transcription of the anthocyanin biosynthesis genes encoding flavanone 3-hydroxylase, dihydroflavonol 4-reductase, and anthocyanidin synthase. In contrast to these repression effects, fungal inoculation resulted in the synthesis of the four known 3-deoxyanthocyanidin phytoalexins and a corresponding activation of genes encoding the key branch-point enzymes in the phenylpropanoid pathway, phenylalanine ammonia-lyase and chalcone synthase. In addition, a gene encoding the pathogenesis-related protein PR-10 was strongly induced in response to inoculation. The accumulation of phytoalexins leveled off by 48 h after inoculation and was accompanied by a more rapid increase in the rate of anthocyanin accumulation. The results suggest that the plant represses less essential metabolic activities such as anthocyanin synthesis as a means of compensating for the immediate biochemical and physiological needs for the defense response.
Purification and Characterization of Peroxidases Correlated with Lignification in Poplar Xylem1
Authors: Christensen Jørgen Holst , Bauw Guy , Gjesing Welinder Karen , Van Montagu Marc , Boerjan Wout
Published: July 2002

Lignin is an integral cell wall component of all vascular plants. Peroxidases are widely believed to catalyze the last enzymatic step in the biosynthesis of lignin, the dehydrogenation of the p-coumaryl alcohols. As the first stage in identifying lignin-specific peroxidase isoenzymes, the classical anionic peroxidases found in the xylem of poplar (Populus trichocarpa Trichobel) were purified and characterized. Five different poplar xylem peroxidases (PXP 1, PXP 2, PXP 3–4, PXP 5, and PXP 6) were isolated. All five peroxidases were strongly glycosylated (3.6% to 4.9% N-glucosamine), with apparent molecular masses between 46 and 54 kD and pI values between pH 3.1 and 3.8. Two of the five isolated peroxidases (PXP 3–4 and PXP 5) could oxidize the lignin monomer analog syringaldazine, an activity previously correlated with lignification in poplar. Because these isoenzymes were specifically or preferentially expressed in xylem, PXP 3–4 and PXP 5 are suggested to be involved in lignin polymerization.
Rapid Regulation by Acid pH of Cell Wall Adjustment and Leaf Growth in Maize Plants Responding to Reversal of Water Stress
Authors: Bogoslavsky Lev , Neumann Peter M.
Published: July 2002

The role of acid secretion in regulating short-term changes in growth rate and wall extensibility was investigated in emerging first leaves of intact, water-stressed maize (Zea mays L.) seedlings. A novel approach was used to measure leaf responses to injection of water or solutions containing potential regulators of growth. Both leaf elongation and wall extensibility, as measured with a whole-plant creep extensiometer, increased dramatically within minutes of injecting water, 0.5 mm phosphate, or strong (50 mm) buffer solutions with pH ≤ 5.0 into the cell-elongation zone of water-stressed leaves. In contrast, injecting buffer solutions at pH ≥ 5.5 inhibited these fast responses. Solutions containing 0.5 mm orthovanadate or erythrosin B to inhibit wall acidification by plasma membrane H+-ATPases were also inhibitory. Thus, cell wall extensibility and leaf growth in water-stressed plants remained inhibited, despite the increased availability of (injected) water when accompanying increases in acid-induced wall loosening were prevented. However, growth was stimulated when pH 4.5 buffers were included with the vanadate injections. These findings suggest that increasing the availability of water to expanding cells in water-stressed leaves signals rapid increases in outward proton pumping by plasma membrane H+-ATPases. Resultant increases in cell wall extensibility participate in the regulation of water uptake, cell expansion, and leaf growth.
Myo-Inositol-Dependent Sodium Uptake in Ice Plant1
Authors: Nelson Donald E. , Koukoumanos Michelle , Bohnert Hans J.
Published: July 2002

In salt-stressed ice plants (Mesembryanthemum crystallinum), sodium accumulates to high concentrations in vacuoles, and polyols (myo-inositol,d-ononitol, and d-pinitol) accumulate in the cytosol. Polyol synthesis is regulated by NaCl and involves induction and repression of gene expression (D.E. Nelson, B. Shen, and H.J. Bohnert [1998] Plant Cell 10: 753–764). In the study reported here we found increased phloem transport of myo-inositol and reciprocal increased transport of sodium and inositol to leaves under stress. To determine the relationship between increased translocation and sodium uptake, we analyzed the effects of exogenous application of myo-inositol: The NaCl-inducible ice plant myo-inositol 1-phosphate synthase is repressed in roots, and sodium uptake from root to shoot increases without stimulating growth. Sodium uptake and transport through the xylem was coupled to a 10-fold increase of myo-inositol and ononitol in the xylem. Seedlings of the ice plant are not salt-tolerant, and yet the addition of exogenousmyo-inositol conferred upon them patterns of gene expression and polyol accumulation observed in mature, salt-tolerant plants. Sodium uptake and transport through the xylem was enhanced in the presence of myo-inositol. The results indicate an interdependence of sodium uptake and alterations in the distribution ofmyo-inositol. We hypothesize thatmyo-inositol could serve not only as a substrate for the production of compatible solutes but also as a leaf-to-root signal that promotes sodium uptake.
An in Vitro System from Maize Seedlings for Tryptophan-Independent Indole-3-Acetic Acid Biosynthesis1
Authors: Östin Anders , Ilić Nebojsa , Cohen Jerry D.
Published: July 2002

The enzymatic synthesis of indole-3-acetic acid (IAA) from indole by an in vitro preparation from maize (Zea mays L.) that does not use tryptophan (Trp) as an intermediate is described. Light-grown seedlings of normal maize and the maize mutant orange pericarp were shown to contain the necessary enzymes to convert [14C]indole to IAA. The reaction was not inhibited by unlabeled Trp and neither [14C]Trp nor [14C]serine substituted for [14C]indole in this in vitro system. The reaction had a pH optimum greater than 8.0, required a reducing environment, and had an oxidation potential near that of ascorbate. The results obtained with this in vitro enzyme preparation provide strong, additional evidence for the presence of a Trp-independent IAA biosynthesis pathway in plants.
γ-Radiation Induces Leaf Trichome Formation in Arabidopsis1
Authors: Nagata Toshifumi , Todoriki Setsuko , Hayashi Toru , Shibata Yuriko , Mori Masaki , Kanegae Hiromi , Kikuchi Shoshi
Published: July 2002

We observed induction of additional trichome formation on the adaxial surface of mature leaves of Arabidopsis after massive doses (1–3 kilograys) of γ-radiation from cobalt-60. A typical increase in trichome number was observed in the seventh leaf when the full expansion of the fifth leaf was irradiated. Under normal growth conditions, trichome numbers on the adaxial surface of seventh leaf of the Arabidopsis ecotypes Columbia (Col) and Landsberg erecta (Ler) were 122.5 ± 22.7 and 57.5 ± 14.5, respectively. However, γ-radiation induced additional trichome formation and the numbers rose to 207.9 ± 43.7 and 95.0 ± 27.1 in Col and Ler, respectively. In Col the shape of new trichomes was intact and their formation was spatially maintained at equal distances from other trichomes. In Ler trichome morphology was aberrant and the formation was relatively random. Treatment with antioxidants before γ-irradiation suppressed the increase in trichome number, and treatment with methyl viologen and light induced small trichomes. These results suggest that γ-radiation-induced trichome formation is mediated by active oxygen species generated by water radiolysis. γ-Radiation-induced trichome formation was blocked in the trichome mutants ttg-1, gl1-1, andgl2-1. These results suggest that γ-radiation-induced trichome formation is mediated by the normal trichome developmental pathway.
Inhibition of Water Channels by HgCl2 in Intact Wheat Root Cells1
Authors: Zhang Wen-Hao , Tyerman Stephen D.
Published: July 2002

To assess the extent of water flow through channels in the membranes of intact higher plant cells, the effects of HgCl2 on hydraulic conductivity (LP) of wheat (Triticum aestivum L.) root cells were investigated using a pressure probe. The LP of root cells was reduced by 75% in the presence of 100 μm HgCl2. The K+-channel blocker tetraethylammonium had no effect on theLP at concentrations that normally block K+ channels. HgCl2 rapidly depolarized the membrane potential (Vm) of the root cells. The dose-response relationship of inhibition ofLP and depolarization ofVm were not significantly different, with half-maximal inhibition occurring at 4.6 and 7.8 μm, respectively. The inhibition of LP and the depolarization of Vm caused by HgCl2 were partially reversed by β-mercaptoethanol. The inhibition of LP by HgCl2 was similar in magnitude to that caused by hypoxia, and the addition of HgCl2 to hypoxia-treated cells did not result in further inhibition. We compared the LP of intact cells with that predicted from a model of cortical cells incorporating water flow across both the plasma membrane and the tonoplast using measured values of water permeability from isolated membranes, and found that HgCl2 has other effects in addition to the direct inhibition of water channels.
The arcelin-5 Gene of Phaseolus vulgarisDirects High Seed-Specific Expression in TransgenicPhaseolus acutifolius and Arabidopsis Plants1
Authors: Goossens Alain , Dillen Willy , De Clercq Janniek , Van Montagu Marc , Angenon Geert
Published: July 2002

The regulatory sequences of many genes encoding seed storage proteins have been used to drive seed-specific expression of a variety of proteins in transgenic plants. Because the levels at which these transgene-derived proteins accumulate are generally quite low, we investigated the utility of the arcelin-5 regulatory sequences in obtaining high seed-specific expression in transgenic plants. Arcelin-5 is an abundant seed protein found in some wild common bean (Phaseolus vulgaris L.) genotypes. Seeds of Arabidopsis and Tepary bean (Phaseolus acutifolius A. Gray) plants transformed with arcelin-5 gene constructs synthesized arcelin-5 to levels of 15% and 25% of the total protein content, respectively. To our knowledge, such high expression levels directed by a transgene have not been reported before. The transgenic plants also showed low plant-to-plant variation in arcelin expression. Complex transgene integration patterns, which often result in gene silencing effects, were not associated with reduced arcelin-5expression. High transgene expression was the result of high mRNA steady-state levels and was restricted to seeds. This indicates that all requirements for high seed-specific expression arecis elements present in the cloned genomicarcelin-5 sequence and trans-acting factors that are available in Arabidopsis and Phaseolusspp., and thus probably in most dicotyledonous plants.
Metabolite Control Overrides Circadian Regulation of Phosphoenolpyruvate Carboxylase Kinase and CO2 Fixation in Crassulacean Acid Metabolism
Authors: Borland Anne M. , Hartwell James , Jenkins Gareth I. , Wilkins Malcolm B. , Nimmo Hugh G.
Published: July 2002

Phosphoenolpyruvate carboxylase (PEPc) catalyzes the primary fixation of CO2 in Crassulacean acid metabolism plants. Flux through the enzyme is regulated by reversible phosphorylation. PEPc kinase is controlled by changes in the level of its translatable mRNA in response to a circadian rhythm. The physiological significance of changes in the levels of PEPc-kinase-translatable mRNA and the involvement of metabolites in control of the kinase was investigated by subjectingKalanchoë daigremontiana leaves to anaerobic conditions at night to modulate the magnitude of malate accumulation, or to a rise in temperature at night to increase the efflux of malate from vacuole to cytosol. Changes in CO2 fixation and PEPc kinase activity reflected those in kinase mRNA. The highest rates of CO2 fixation and levels of kinase mRNA were observed in leaves subjected to anaerobic treatment for the first half of the night and then transferred to ambient air. In leaves subjected to anaerobic treatment overnight and transferred to ambient air at the start of the day, PEPc-kinase-translatable mRNA and activity, the phosphorylation state of PEPc, and fixation of atmospheric CO2 were significantly higher than those for control leaves for the first 3 h of the light period. A nighttime temperature increase from 19°C to 27°C led to a rapid reduction in kinase mRNA and activity; however, this was not observed in leaves in which malate accumulation had been prevented by anaerobic treatment. These data are consistent with the hypothesis that a high concentration of malate reduces both kinase mRNA and the accumulation of the kinase itself.
Interaction Specificity of Arabidopsis Calcineurin B-Like Calcium Sensors and Their Target Kinases
Authors: Kim Kyung-Nam , Cheong Yong Hwa , Gupta Rajeev , Luan Sheng
Published: July 2002

Calcium is a critical component in a number of plant signal transduction pathways. A new family of calcium sensors called calcineurin B-like proteins (AtCBLs) have been recently identified from Arabidopsis. These calcium sensors have been shown to interact with a family of protein kinases (CIPKs). Here we report that each individual member of AtCBL family specifically interacts with a subset of CIPKs and present structural basis for the interaction and for the specificity underlying these interactions. Although the C-terminal region of CIPKs is responsible for interaction with AtCBLs, the N-terminal region of CIPKs is also involved in determining the specificity of such interaction. We have also shown that all three EF-hand motifs in AtCBL members are required for the interaction with CIPKs. Several AtCBL members failed to interact with any of the CIPKs presented in this study, suggesting that these AtCBL members either have other CIPKs as targets or they target distinct proteins other than CIPKs. These results may provide structural basis for the functional specificity of CBL family of calcium sensors and their targets.
Ion Channel-Forming Alamethicin Is a Potent Elicitor of Volatile Biosynthesis and Tendril Coiling. Cross Talk between Jasmonate and Salicylate Signaling in Lima Bean
Authors: Engelberth Jürgen , Koch Thomas , Schüler Göde , Bachmann Nadine , Rechtenbach Jana , Boland Wilhelm
Published: July 2002

Alamethicin (ALA), a voltage-gated, ion channel-forming peptide mixture from Trichoderma viride, is a potent elicitor of the biosynthesis of volatile compounds in lima bean (Phaseolus lunatus). Unlike elicitation with jasmonic acid or herbivore damage, the blend of substances emitted comprises only the two homoterpenes, 4,11-dimethylnona-1,3,7-triene and 4,8,12-trimethyltrideca-1,3,7,11-tetraene, and methyl salicylate. Inhibition of octadecanoid signaling by aristolochic acid and phenidone as well as mass spectrometric analysis of endogenous jasmonate demonstrate that ALA induces the biosynthesis of volatile compounds principally via the octadecanoid-signaling pathway (20-fold increase of jasmonic acid). ALA also up-regulates salicylate biosynthesis, and the time course of the production of endogenous salicylate correlates well with the appearance of the methyl ester in the gas phase. The massive up-regulation of the SA-pathway (90-fold) interferes with steps in the biosynthetic pathway downstream of 12-oxophytodienoic acid and thereby reduces the pattern of emitted volatiles to compounds previously shown to be induced by early octadecanoids. ALA also induces tendril coiling in various species like Pisum, Lathyrus, and Bryonia, but the response appears to be independent from octadecanoid biosynthesis, because inhibitors of lipoxygenase and phospholipase A2 do not prevent the coiling reaction.
Altered Patterns of Sucrose Synthase Phosphorylation and Localization Precede Callose Induction and Root Tip Death in Anoxic Maize Seedlings
Authors: Subbaiah Chalivendra C. , Sachs Martin M.
Published: July 2002

Root extracts made from maize (Zea mays) seedlings submerged for 2 h showed an increased 32P-labeling of a 90-kD polypeptide in a Ca2+-dependent manner. This protein was identified as sucrose synthase (SS) by immunoprecipitation and mutant analysis. Metabolic labeling with32Pi indicated that the aerobic levels of SS phosphorylation were maintained up to 2 h of anoxia. In contrast, during prolonged anoxia the protein was under-phosphorylated, and by 48 h most of the protein existed in the unphosphorylated form. In seedlings submerged for 2 h or longer, a part of SS became associated with the microsomal fraction and this membrane localization of SS was confined only to the root tip. This redistribution of SS in the root tip preceded callose induction, an indicator of cell death. The sh1 mutants showed sustained SS phosphorylation and lacked the anoxia-induced relocation of SS, indicating that it was the SH1 form of the enzyme that was redistributed during anoxia. Thesh1 mutants also showed less callose deposition and greater tolerance to prolonged anoxia than their non-mutant siblings. EGTA accentuated anoxic effects on membrane localization of SS and callose accumulation, whereas Ca2+ addition reversed the EGTA effects. These results indicate that the membrane localization of SS is an important early event in the anoxic root tip, probably associated with the differential anoxic tolerance of the two SS mutants. We propose that beside the transcriptional control of genes encoding SS, the reversible phosphorylation of SS provides a potent regulatory mechanism of sugar metabolism in response to developmental and environmental signals.
Altered Middle Lamella Homogalacturonan and Disrupted Deposition of (1→5)-α-l-Arabinan in the Pericarp ofCnr, a Ripening Mutant of Tomato
Authors: Orfila Caroline , Seymour Graham B. , Willats William G.T. , Huxham I. Max , Jarvis Michael C. , Dover Colin J. , Thompson Andrew J. , Knox J. Paul
Published: July 2002

Cnr (colorless non-ripening) is a pleiotropic tomato (Lycopersicon esculentum) fruit ripening mutant with altered tissue properties including weaker cell-to-cell contacts in the pericarp (A.J. Thompson, M. Tor, C.S. Barry, J. Vrebalov, C. Orfila, M.C. Jarvis, J.J. Giovannoni, D. Grierson, G.B. Seymour [1999] Plant Physiol 120: 383–390). Whereas the genetic basis of theCnr mutation is being identified by molecular analyses, here we report the identification of cell biological factors underlying the Cnr texture phenotype. In comparison with wild type, ripe-stage Cnr fruits have stronger, non-swollen cell walls (CW) throughout the pericarp and extensive intercellular space in the inner pericarp. Using electron energy loss spectroscopy imaging of calcium-binding capacity and anti-homogalacturonan (HG) antibody probes (PAM1 and JIM5) we demonstrate that maturation processes involving middle lamella HG are altered in Cnr fruit, resulting in the absence or a low level of HG-/calcium-based cell adhesion. We also demonstrate that the deposition of (1→5)-α-l-arabinan is disrupted in Cnr pericarp CW and that this disruption occurs prior to fruit ripening. The relationship between the disruption of (1→5)-α-l-arabinan deposition in pericarp CW and theCnr phenotype is discussed.