bluuebunny/crossref_metadata_2025 huggingface dataset:
de Bruijn notation as a nested datatype
Authors: BIRD RICHARD S. , PATERSON ROSS
Published: July 2002

“I have no data yet. It is a capital mistake to
theorise before one has data.”
Sir Arthur Conan Doyle The Adventures of Sherlock Holmes

de Bruijn notation is a coding of lambda terms in which each occurrence of a bound variable
x is replaced by a natural number, indicating the ‘distance’
from the occurrence to the abstraction
that introduced x. One might suppose that in any datatype for representing de Bruijn terms,
the distance restriction on numbers would have to be maintained as an explicit datatype invariant.
However, by using a nested (or non-regular) datatype, we can define a representation in which
all terms are well-formed, so that the invariant is enforced automatically by the type system.
Programming with nested types is only a little more difficult than programming with regular
types, provided we stick to well-established structuring techniques. These involve expressing
inductively defined functions in terms of an appropriate fold function for the type, and using
fusion laws to establish their properties. In particular, the definition of lambda abstraction
and beta reduction is particularly simple, and the proof of their associated properties is
entirely mechanical.
Transparent optimisation of rewriting combinators
Authors: BOULTON RICHARD J.
Published: July 2002

The LCF system was the first mechanical theorem prover to be user-programmable via a
metalanguage, ML, from which the functional programming language Standard ML has been
developed. Paulson has demonstrated how a modular rewriting engine can be implemented
in LCF. This provides both clarity and flexibility. This paper shows that the same modular
approach (using higher-order functions) allows transparent optimisation of the rewriting
engine; performance can be improved while few, if any, changes are required to code written
using these functions. The techniques described have been implemented in the HOL system,
a descendant of LCF, and some are now in daily use. Comparative results are given. Some
of the techniques described, in particular ones to avoid processing parts of a data structure
that do not need to be changed, may be of more general use in functional programming and
beyond.
Editorial
Authors: Woodhouse Ken
Published: July 2002

The last year has seen much change in Reviews in Clinical Gerontology, and this will continue over the next year.

At the beginning of last year I took over as Editor from Professor Ray Tallis, whose vision, drive and initiative were instrumental in establishing what Age Ageing has recently referred to as one of the major review journals in the field on gerontology. The year also saw a major change in the section editors, the only one remaining from l’ancien regime being Bob Baldwin, our section editor for Old Age Psychiatry. The contributions of David Barer, Ioan Davies, Emily Grundy, Jackie Oldham and Peter Overstall have been considerable, and their contribution, with Ray, to Reviews cannot be understated.
The influence of linguistic and social factors on the recent decline of French ne
Authors: Armstrong Nigel , Smith Alan
Published: July 2002

In this article we present some results showing the decline in radio speech in the use of the French negative particle ne over the last forty years or so. These results derive from a comparison of two radio corpora: an archival corpus recorded by Ågren (1973) in 1960–61. The second, contemporary corpus was recorded and analysed by one of the present authors (Smith) in 1997. Having described the variable in question, we present these corpora in turn and analyse results deriving from them. We then examine some of the linguistic constraints that endorse the progressive decline of ne in some contexts while hindering the process in others. Finally we consider some elements of the social context within which the decline of ne has been occurring.
A NEW SPECIES OF ROSCOEA SM. (ZINGIBERACEAE) FROM BHUTAN AND SOUTHERN TIBET
Authors: NGAMRIABSAKUL C. , NEWMAN M. F.
Published: July 2002

A new species of Roscoea from Bhutan and southern Tibet, R. bhutanica Ngamriab., formerly included in R. tibetica Batalin, is described and a new key to all species of Roscoea is provided. While studying the phylogeny of Roscoea, we discovered that there is a correspondence between phylogeny and biogeography (Ngamriabsakul et al., 2000). There are two distinct areas of distribution in Roscoea, namely the Himalaya and China. Only R. tibetica has been recorded in both areas. Cowley (1982) indicated that this species was very variable and suggested that it might be divided. We now propose to name a new species, R. bhutanica, based on observation of living and herbarium material at the Royal Botanic Garden Edinburgh (RBGE) and a molecular systematic study. A morphological table comparing R. tibetica with R. bhutanica is given, along with the ITS sequences of R. tibetica, R. bhutanica and R. auriculata. The identification key to Roscoea species largely follows our phylogenetic tree (Ngamriabsakul et al., 2000).
Nutritional aspects of polycystic ovary syndrome
Authors: Norman RJ , Moran L , Davies MJ
Published: July 2002

There is ample evidence from animal and human observations that extremes of body weight influence reproductive processes. Women who are under a certain weight or body mass index are less likely to cycle regularly, have more difficulty in getting pregnant and have smaller babies. Those who are overweight also suffer serious reproductive problems in that they have a greater risk of oligo- or amenorrhoea, infertility and gestational diabetes. Several large epidemiological studies indicate that reproduction is adversely affected by excess weight. Two of the largest studies (Nurses' Health Study and the British Birth Cohort Study) that convincingly show that being overweight impairs menstrual and fertility function indicate that the greater the body weight and body mass index (BMI), the more significant the effect. Being overweight in adolescence appears to affect reproductive function later in life.
Reply to Burdick: Constraining Physician Discretion
Authors: Himma Kenneth Einar
Published: July 2002

In “A Critique of UNOS Liver Allocation Policy,”
I argued that the UNOS policy of placing acute liver failure
patients (ALF patients) above chronic liver failure patients
(CLF patients) on the transplant list fails to satisfy
the principles of utility and justice that ostensibly guide
UNOS allocation policy. Further, I argued that physician
discretion in evaluating ALF and CLF patients should be
expanded—not constrained. In response, Dr. Burdick
attempts to justify the policy constraints on physician
discretion on the strength of objective differences between
ALF and CLF; as he puts it, “the distinction between
acute liver failure and progression of chronic liver disease
… is clear in the way brain death is.”
Alzheimer Testing at Silver Years
Authors: THOMAS A. MATHEW , COHEN GENE , COOK-DEEGAN ROBERT M. , O'SULLIVAN JOAN , POST STEPHEN G. , ROSES ALLEN D. , SCHAFFNER KENNETH F. , GREEN RONALD M.
Published: July 2002

Early last year, the GenEthics Consortium (GEC)
of the Washington Metropolitan Area convened at George
Washington University to consider a complex case about
genetic testing for Alzheimer disease (AD). The GEC consists
of scientists, bioethicists, lawyers, genetic counselors,
and consumers from a variety of institutions and affiliations.
Four of the 8 co-authors of this paper delivered presentations
on the case. Supplemented by additional ethical and legal
observations, these presentations form the basis for the
following discussion.
Imperfect workers – imperfect answers: recent publications on the history of women and work
Authors: D'Cruze Shani
Published: July 2002

Historically speaking, women's purposeful activities have contributed significantly to the uses and meanings of urban spaces and have been a key part of the texture of social and economic relationships in town and city as well as the countryside. A good deal of the scholarship which underpins this conclusion has called for the detailed study of particular historical situations: the domestic economy in industrializing Montreal, dairying in mid-twentieth-century Denmark, gossip in the back yards and closes of inter-war Manchester. Methods of inquiry such as oral history or the close examination of census data necessarily lend themselves to the case study approach. This kind of detailed investigation has encouraged re-examination of some of the overarching meta-narratives of historical change more characteristic of earlier historical studies of women and work, notably that of Tilly and Scott.
Oxytocin antagonists in the treatment of preterm labour
Authors: Åkerlund Mats
Published: July 2002

Despite substantial advances in pre- and postnatal care, the problem of preterm labour continues to be a significant medical, economic and social burden. Globally, it is estimated that 13 million babies are born preterm each year, but the incidence varies substantially between different countries and population groups. In the United States alone, approximately 11% of pregnancies, i.e. 380,000 cases annually are delivered after preterm labour and in Europe the overall incidence is believed to be approximately 6%, representing an annual population of 375,000. The main complication of very early preterm birth to the newborn is immaturity of different organs, in particular incomplete maturation of the lungs. However, a recent multi-centre surveillance study demonstrated that also modest degrees of prematurity are associated with developmental delays, implying that adequate intrauterine maturation of the fetus is vital to postnatal development.
SONNETS FROM THE PORTUGUESE AND THE POLITICS OF RHYME
Authors: Morlier Margaret M.
Published: July 2002

ALTHOUGH VICTORIAN REVIEWERS uniformly praised Elizabeth Barrett Browning for the “sincere” poetic voice of Sonnets from the Portuguese, they often blamed her for faulty craft. In structure and rhyme scheme the poems in the sequence recall the Petrarchan tradition, suggesting the idealized love that accompanies it, yet their varied syntax and diction seem more conversational than ideal. Enjambment usually destroys the integrity of octave and sestet. Then in the Sonnets Barrett Browning continued her use of odd rhymes, which had been raising critical eyebrows since earlier poems. For example, in the most famous sonnet — XLIII, “How do I love thee?” — Barrett Browning rhymed the noun phrase “put to use” (9) with the infinitive “to lose” (11) and rhymed “faith” (10) with “breath” (12). Victorian reviewers, somewhat disoriented, offered a variety of explanations for these apparent technical lapses. Some attributed them to a defective ear for music (“Review of Poems” 278; [Massey] 517).1 George Saintsbury — taking the lead from the controversy over the “cockney school” of poetry — reproved Barrett Browning, born to the educated classes, for relying out of laziness on vulgar pronunciation to force rhymes instead of taking the time to discover correct ones (280–81). Even her poet-friend and correspondent, Mary Russell Mitford, wondered if isolation at Wimpole Street had led to an overly narrow experience with proper pronunciation of English (reported in Horne 458; see also Hayter 38–39). Victorian reproofs and anecdotes like these followed Barrett Browning’s work into the formalist twentieth century.
Learning to read is much more than learning to read: A
neuropsychologically based reading program
Authors: ARDILA ALFREDO , OSTROSKY-SOLIS FEGGY , MENDOZA VICTOR U.
Published: July 2002

Departing from the observation that illiterates
significantly underscore in some neuropsychological tests,
a learning-to-read method named NEUROALFA was developed.
NEUROALFA is directed to reinforce these underscored abilities
during the learning-to-read process. It was administered
to a sample of 21 adult illiterates in Colima (Mexico).
Results were compared with 2 control groups using more
traditional procedures in learning to read. The NEUROPSI
neuropsychological test battery was administered to all
the participants before and after completing the learning-to-read
training program. All 3 groups presented some improvement
in the test scores. Gains, however, were significantly
higher in the experimental group in Orientation in Time,
Digits Backward, Visual Detection, Verbal Memory, Copy
of a Semi-Complex Figure, Language Comprehension, Phonological
Verbal Fluency, Similarities, Calculation Abilities, Sequences,
and all the recall subtests, excluding Recognition. Performance
in standard reading tests was also significantly higher
in the experimental group. Correlations between pretest
NEUROPSI scores and reading ability were low. However,
correlations between posttest NEUROPSI scores and reading
scores were higher and significant for several subtests.
Results are interpreting as supporting the assumption that
reinforcement of those abilities in which illiterates significantly
underscore results in a significant improvement in neuropsychological
test scores and strongly facilitates the learning-to-read
process. The NEUROALFA method of teaching reading to adult
illiterates is beginning to be used extensively in Mexico.
To our knowledge, this is the first attempt to apply neuropsychological
principles to social problems. (JINS, 2000, 6,
789–801.)
The problem of 2nd-order sonorities in Xenakis’ electracoustic music
Authors: DI SCIPIO AGOSTINO
Published: July 2002

Working on Analogique B in the late 1950s, Xenakis formulated the
‘hypothesis of a second order sonority’. This paper focuses on
this concept, and shows its crucial meaning in the composition of a number
of pieces, such as Concret PH, Analogique B and the very recent
Gendy3 and S709. The perspective taken is twofold: on one side, the problem of 2nd-order
sonorities is seen as a problem in modelling perceptual attributes
(or timbre) of sound in terms of ‘emergent properties
of organised sound structure’. This is also related to the
composer’s pioneering work with granular sound representations and
nonstandard methods of sound synthesis. On the other, the issue is
discussed in conjunction with Xenakis’ attempt at implementing
thoroughly formalised ‘mechanisms’ or ‘systems’
based on the mathematics of stochastic processes. The paper shows that the
issue touched on here is essential to the aesthetics of Xenakis’
electroacoustic music. It also questions whether the formalisation of
stochastics is a suitable means to let 2nd-order sonorities emerge from the
internal life of the sound matter. The limitations of Xenakis’
‘mechanisms’ are described in terms of their cybernetics, and
are situated in the context of artistic and scientific paradigm shifts
concerning the relationship between order, disorder and chaos.
The influence of plant age on tolerance of rice to injury by the rice water weevil, Lissorhoptrus oryzophilus (Coleoptera: Curculionidae)
Authors: Stout M.J. , Rice W.C. , Ring D.R.
Published: July 2002

For most plant species, tolerance to many types of herbivory increases as plants age, but the applicability of this pattern to root herbivory has not been tested. Injury to roots of rice plants by larvae of the rice water weevil, Lissorhoptrus oryzophilus Kuschel, causes severe reductions in yields in the United States. It is generally thought that young rice plants, because their root systems are smaller, are less tolerant than older plants of root feeding by L. oryzophilus. Field experiments were conducted to test this hypothesis. Plots of rice (4.7 to 6.5 m2) were established and subjected to natural infestations of L. oryzophilus larvae. A soil insecticide was applied to plots at different times during the tillering phase of rice in order to manipulate the timing of weevil infestation. The impact of these treatments (timings of insecticide applications) was assessed by comparing relationships between yield loss and larval pressure for each treatment using analysis of covariance. Yield losses ranged from 13% to over 40% in plots not treated with insecticide. Patterns of yield losses from plots treated with insecticide at different times were best explained by the hypothesis that yield loss is determined both by the age of plants infested and by the size of larvae infesting plants. Young plants appear to be less tolerant than older plants, and feeding by large larvae appears to be more deleterious than feeding by smaller larvae. Management practices that delay infestation of rice by L. oryzophilus until plants are older may be an important component of management programmes for this pest.
The unfolded protein response represses nitrogen-starvation induced developmental differentiation in yeast
Authors: Schröder Martin , Chang Jason S. , Kaufman Randal J.
Published: July 2002

Diploid budding yeast exhibits two developmental programs in response to nitrogen starvation, pseudohyphal growth, and sporulation. Here we show that both programs are repressed by activation of the unfolded protein response (UPR), a stress-signal transduction pathway responsible for induction of endoplasmic reticulum (ER)-resident chaperones when protein folding in the ER is impaired. Pseudohyphal growth was derepressed in ire1Δ/ire1Δ andhac1Δ/hac1Δ strains. Activation of the UPR or overexpression of the transcription factor Hac1ip, the product of an unconventional splicing reaction regulated by the UPR, was sufficient for repression of pseudohyphal growth and meiosis.HAC1 splicing occurred in a nitrogen-rich environment but ceased rapidly on nitrogen starvation. Further, addition of ammonium salts to nitrogen-starved cells was sufficient to rapidly reactivateHAC1 splicing. We propose that high translation rates in a nitrogen-rich environment are coupled to limited protein unfolding in the ER, thereby activating the UPR. An activated UPR then represses pseudohyphal growth and meiosis. Nitrogen starvation slows translation rates, allowing for more efficient folding of nascent polypeptide chains, down-regulation of the UPR, and subsequent derepression of pseudohyphal growth and meiosis. These findings significantly broaden the range of physiological functions of the UPR and define a role for the UPR in nitrogen sensing.
Arabidopsis cmt3 chromomethylase mutations block non-CG methylation and silencing of an endogenous gene
Authors: Bartee Lisa , Malagnac Fabienne , Bender Judith
Published: July 2002

Plants maintain cytosine methylation at CG and non-CG residues to control gene expression and genome stability. In a screen forArabidopsis mutants that alter methylation and silencing of a densely methylated endogenous reporter gene, we recovered 11 loss-of-function alleles in the CMT3 chromomethylase gene. Thecmt3 mutants displayed enhanced expression and reduced methylation of the reporter, particularly at non-CG cytosines. CNG methylation was also reduced at repetitive centromeric sequences. Thus,CMT3 is a key determinant for non-CG methylation. The lack ofCMT homologs in animal genomes could account for the observation that in contrast to plants, animals maintain primarily CG methylation.
Cloning and Functional Analysis of cDNAs with Open Reading Frames for 300 Previously Undefined Genes Expressed in CD34+ Hematopoietic Stem/Progenitor Cells
Authors: Zhang Qing-Hua , Ye Min , Wu Xin-Yan , Ren Shuang-Xi , Zhao Meng , Zhao Chun-Jun , Fu Gang , Shen Yu , Fan Hui-Yong , Lu Gang , Zhong Ming , Xu Xiang-Ru , Han Ze-Guang , Zhang Ji-Wang , Tao Jiong , Huang Qiu-Hua , Zhou Jun , Hu Geng-Xi , Gu Jian , Chen Sai-Juan , Chen Zhu
Published: July 2002

Three hundred cDNAs containing putatively entire open reading frames (ORFs) for previously undefined genes were obtained from CD34+ hematopoietic stem/progenitor cells (HSPCs), based on EST cataloging, clone sequencing, in silico cloning, and rapid amplification of cDNA ends (RACE). The cDNA sizes ranged from 360 to 3496 bp and their ORFs coded for peptides of 58–752 amino acids. Public database search indicated that 225 cDNAs exhibited sequence similarities to genes identified across a variety of species. Homology analysis led to the recognition of 50 basic structural motifs/domains among these cDNAs. Genomic exon–intron organization could be established in 243 genes by integration of cDNA data with genome sequence information. Interestingly, a new gene named as HSPC070 on 3p was found to share a sequence of 105bp in 3′ UTR with RAF gene in reversed transcription orientation. Chromosomal localizations were obtained using electronic mapping for 192 genes and with radiation hybrid (RH) for 38 genes. Macroarray technique was applied to screen the gene expression patterns in five hematopoietic cell lines (NB4, HL60, U937, K562, and Jurkat) and a number of genes with differential expression were found. The resource work has provided a wide range of information useful not only for expression genomics and annotation of genomic DNA sequence, but also for further research on the function of genes involved in hematopoietic development and differentiation.

[The sequence data described in this paper have been submitted to the GenBank data library under the accession nos. listed in Table 1, pp 1548–1552.]
Neuropeptides and Neuropeptide Receptors in the Drosophila melanogaster Genome
Authors: Hewes Randall S. , Taghert Paul H.
Published: July 2002

Recent genetic analyses in worms, flies, and mammals illustrate the importance of bioactive peptides in controlling numerous complex behaviors, such as feeding and circadian locomotion. To pursue a comprehensive genetic analysis of bioactive peptide signaling, we have scanned the recently completed Drosophila genome sequence for G protein-coupled receptors sensitive to bioactive peptides (peptide GPCRs). Here we describe 44 genes that represent the vast majority, and perhaps all, of the peptide GPCRs encoded in the fly genome. We also scanned for genes encoding potential ligands and describe 22 bioactive peptide precursors. At least 32 Drosophila peptide receptors appear to have evolved from common ancestors of 15 monophyletic vertebrate GPCR subgroups (e.g., the ancestral gastrin/cholecystokinin receptor). Six pairs of receptors are paralogs, representing recent gene duplications. Together, these findings shed light on the evolutionary history of peptide GPCRs, and they provide a template for physiological and genetic analyses of peptide signaling in Drosophila.
A Comprehensive View of Human Chromosome 1
Authors: White Peter S. , Sulman Erik P. , Porter Christopher J. , Matise Tara C.
Published: July 2002

Comprehensive representations of human chromosomes combining diverse genomic data sets, localizing expressed sequences, and reflecting physical distance are essential for disease gene identification and sequencing efforts. We have developed a method (CompView) for integrating genomic information derived from available cytogenetic, genetic linkage, radiation hybrid, physical, and transcript-based mapping approaches. CompView generates chromosome representations with substantially higher resolution, coverage, and integration than current maps of the human genome. The CompView process was used to build a representation of human chromosome 1, yielding a map with >13,000 unique elements, an effective resolution of 910 kb, and a marker density of 50 kb. CompView creates comprehensive and fully integrated depictions of a chromosome's clinical, biological, and structural information.
Interaction of the Arabidopsis E2F and DP Proteins Confers Their Concomitant Nuclear Translocation and Transactivation
Authors: Kosugi Shunichi , Ohashi Yuko
Published: July 2002

E2F transcription factors are required for the progression and arrest of the cell cycle in animals. Like animals, plants have evolved to conserve the E2F family. The Arabidopsis genome encodes E2F and DP proteins that share a high similarity with the animal E2F and DP families. Here, we show that Arabidopsis E2F and DP proteins are not predominantly localized to the nucleus in analyses with green fluorescent protein, and that the complete nuclear localization of some members is driven by the co-expression of their specific partner proteins. Both AtE2F1 and AtE2F3 were translocated to the nucleus and transactivate an E2F reporter gene when co-expressed with DPa but not DPb. In contrast, AtE2F2 was inactive for both nuclear translocation and transactivation even when Dpa or DPb was co-expressed. Because the DNA binding activities of the three E2Fs are equally stimulated by the interaction with DPa or DPb in vitro, the observed transactivation of AtE2F1 and AtE2F3 is DPa specific and nuclear import dependent. A green fluorescent protein fusion with an AtE2F3 mutant, in which a conserved nuclear export signal-like sequence in the dimerization domain was deleted, was localized to the nucleus. Thus, the concomitant nuclear translocation seems to be conferred by the DPa interaction to release an activity that inhibits an intrinsic nuclear import activity of AtE2Fs. Furthermore, the nuclear translocation of AtE2F3 stimulated by DPa was abolished by the deletion of the N-terminal region of AtE2F3, which is conserved among all the E2F proteins identified in plants to date. Replacement of the N-terminal region of AtE2F3 with a canonical nuclear localization signal only partially mimicked the effect of the DPa co-expression, demonstrating the function of plant E2F distinct from that observed for animal E2Fs. These observations suggest that the function of plant E2F and DP proteins is primarily controlled by their nuclear localization mediated by the interaction with specific partner proteins.
Gibberellin Produced in the Cotyledon Is Required for Cell Division during Tissue Reunion in the Cortex of Cut Cucumber and Tomato Hypocotyls
Authors: Asahina Masashi , Iwai Hiroaki , Kikuchi Akira , Yamaguchi Shinjiro , Kamiya Yuji , Kamada Hiroshi , Satoh Shinobu
Published: July 2002

Cucumber (Cucumis sativus) hypocotyls were cut to one-half of their diameter transversely, and morphological and histochemical analyses of the process of tissue reunion in the cortex were performed. Cell division in the cortex commenced 3 d after cutting, and the cortex was nearly fully united within 7 d. 4′,6-Diamidino-2-phenylindole staining and 5-bromo-2′-deoxyuridine labeling experiments indicate that nDNA synthesis occurred during this process. In addition, specific accumulation of pectic substances was observed in the cell wall of attached cells in the reunion region of the cortex. Cell division during tissue reunion was strongly inhibited when the cotyledon was removed. This inhibition was reversed by applying gibberellin (GA, 10−4  mGA3) to the apical tip of the cotyledon-less plant. Supporting this observation, cell division in the cortex was inhibited by treatment of the cotyledon with 10−4  municonazole-P (an inhibitor of GA biosynthesis), and this inhibition was also reversed by simultaneous application of GA. In contrast to the essential role of cotyledon, normal tissue reunion in cut hypocotyls was still observed when the shoot apex was removed. The requirement of GA for tissue reunion in cut hypocotyls was also evident in the GA-deficient gib-1 mutant of tomato (Lycopersicon esculentum). Our results suggest that GA, possibly produced in cotyledons, is essential for cell division in reuniting cortex of cut hypocotyls.
Pollen-Stigma Adhesion in Kale Is Not Dependent on the Self-(In)Compatibility Genotype
Authors: Luu D. T. , Heizmann P. , Dumas C.
Published: July 2002

The adhesion of pollen on the stigmas of flowering plants is a critical step for the success of reproduction in angiosperms, long considered to present some specificity in terms of self-incompatibility. We carried out quantitative measurements of the pollen-stigma adhesion (expressed in Newtons) in kale (Brassica oleracea), using the flotation force of Archimedes exerted by dense sucrose solutions (50%, w/v) to release pollen grains fixed on the surface of stigmas. We demonstrate that pollen adhesion varies with the genotypes of the plants used as partners, but increases with time in all cases for about 30 to 60 min after pollination. There is no correlation with the self- or cross-status of the pollinations, nor with the self-compatible or -incompatible genotypes of the parents. Only late events of pollination, after the germination or arrest of the pollen tube, depend on compatibility type. Biochemical and physiological dissection of pollen-stigma adhesion points to major components of this interaction: among male components, the pollen coating, eliminated by delipidation (or modified by mutation in the case of the cer mutants of the related species Arabidopsis thaliana), plays a major role in adhesion; the genetic background of the pollen parent is also of some importance. On the female side, the developmental stage of the stigma and the protein constituents of the stigmatic pellicle are critical for pollen capture. The SLG and SLR1 proteins are not involved in the initial stages of pollen adhesion on the stigma but one or both may be involved in the later stages.
The COW1 Locus of Arabidopsis Acts after RHD2, and in Parallel with RHD3 and TIP1, to Determine the Shape, Rate of Elongation, and Number of Root Hairs Produced from Each Site of Hair Formation
Authors: Grierson C. S. , Roberts K. , Feldmann K. A. , Dolan L.
Published: July 2002

Two recessive mutant alleles at CAN OF WORMS1 (COW1), a new locus involved in root hair morphogenesis, have been identified in Arabidopsis thaliana L. Heynh. Root hairs on Cow1- mutants are short and wide and occasionally formed as pairs at a single site of hair formation. The COW1 locus maps to chromosome 4. Root hairs on Cow1- plants form in the usual positions, suggesting that the phenotype is not the result of abnormal positional signals. Root hairs on Cowl- roots begin hair formation normally, forming a small bulge, or root hair initiation site, of normal size and shape and in the usual position on the hair-forming cell. However, when Cow1- root hairs start to elongate by tip growth, abnormalities in the shape and elongation rate of the hairs become apparent. Genetic evidence from double-mutant analysis of cow1–1 and other loci involved in root hair development supports our conclusion that COW1 is required during root hair elongation.
Nucleotide Triphosphates Are Required for the Transport of Glycolate Oxidase into Peroxisomes1
Authors: Brickner Donna G. , Olsen Laura J.
Published: July 2002

All peroxisomal proteins are nuclear encoded, synthesized on free cytosolic ribosomes, and posttranslationally targeted to the organelle. We have used an in vitro assay to reconstitute protein import into pumpkin (Cucurbita pepo) glyoxysomes, a class of peroxisome found in the cotyledons of oilseed plants, to study the mechanisms involved in protein transport across peroxisome membranes. Results indicate that ATP hydrolysis is required for protein import into peroxisomes; nonhydrolyzable analogs of ATP could not substitute for this requirement. Nucleotide competition studies suggest that there may be a nucleotide binding site on a component of the translocation machinery. Peroxisomal protein import also was supported by GTP hydrolysis. Nonhydrolyzable analogs of GTP did not substitute in this process. Experiments to determine the cation specificity of the nucleotide requirement show that the Mg2+ salt was preferred over other divalent and monovalent cations. The role of a putative protonmotive force across the peroxisomal membrane was also examined. Although low concentrations of ionophores had no effect on protein import, relatively high concentrations of all ionophores tested consistently reduced the level of protein import by approximately 50%. This result suggests that a protonmotive force is not absolutely required for peroxisomal protein import.
Evidence for 1-(Malonylamino)cyclopropane-1-Carboxylic Acid Being the Major Conjugate of Aminocyclopropane-1-Carboxylic Acid in Tomato Fruit1
Authors: Peiser Galen , Fa Yang Shang
Published: July 2002

Tomato (Lycopersicon esculentum Miller) fruit discs fed with [2,3-14C]1-aminocyclopropane-1-carboxylic acid (ACC) formed 1-malonyl-ACC (MACC) as the major conjugate of ACC in fruit throughout all ripening stages, from immature-green through the red-ripe stage. Another conjugate of ACC, γ-glutamyl-ACC (GACC), was formed only in mature-green fruit in an amount about 10% of that of MACC; conjugation of ACC into GACC was not detected in fruits at other ripening stages. No GACC formation was observed from etiolated mung bean (Vigna radiata [L.] Wilczek) hypocotyls, etiolated common vetch (Vicia sativum L.) epicotyls, or pea (Pisum sativum L.) root tips, etiolated epicotyls, and green stem tissue, where active conversion of ACC into MACC was observed. GACC was, however, formed in vitro in extracts from fruit of all ripening stages. GACC formation in an extract from red fruit at pH 7.15 was only about 3% of that at pH 8.0, the pH at which most assays were run. Our present in vivo data support the previous contention that MACC is the major conjugate of ACC in plant tissues, whereas GACC is a minor, if any, conjugate of ACC. Thus, our data do not support the proposal that GACC formation could be more important than MACC formation in tomato fruit.
Differential Regulation of Sugar-Sensitive Sucrose Synthases by Hypoxia and Anoxia Indicate Complementary Transcriptional and Posttranscriptional Responses1
Authors: Zeng Ying , Wu Yong , Avigne Wayne T. , Koch Karen E.
Published: July 2002

The goal of this research was to resolve the hypoxic and anoxic responses of maize (Zea mays) sucrose (Suc) synthases known to differ in their sugar regulation. The two maize Suc synthase genes, Sus1 andSh1, both respond to sugar and O2, and recent work suggests commonalities between these signaling systems. Maize seedlings (NK508 hybrid, W22 inbred, and an isogenicsh1-null mutant) were exposed to anoxic, hypoxic, and aerobic conditions (0, 3, and 21% O2, respectively), when primary roots had reached approximately 5 cm. One-centimeter tips were excised for analysis during the 48-h treatments. At the mRNA level,Sus1 was rapidly up-regulated by hypoxia (approximately 5-fold in 6 h), whereas anoxia had less effect. In contrast,Sh1 mRNA abundance increased strongly under anoxia (approximately 5-fold in 24 h) and was much less affected by hypoxia. At the enzyme level, total Suc synthase activity rose rapidly under hypoxia but showed little significant change during anoxia. The contributions of SUS1 and SH1 activities to these responses were dissected over time by comparing the sh1-null mutant with the isogenic wild type (Sus+, Sh1+).Sh1-dependent activity contributed most markedly to a rapid protein-level response consistently observed in the first 3 h, and, subsequently, to a long-term change mediated at the level of mRNA accumulation at 48 h. A complementary midterm rise in SUS1 activity varied in duration with genetic background. These data highlight the involvement of distinctly different genes and probable signal mechanisms under hypoxia and anoxia, and together with earlier work, show parallel induction of “feast and famine” Suc synthase genes by hypoxia and anoxia, respectively. In addition, complementary modes of transcriptional and posttranscriptional regulation are implicated by these data, and provide a mechanism for sequential contributions from the Sus1 and Sh1 genes during progressive onset of naturally occurring low-O2events.
Dimethylsulfoniopropionate Biosynthesis inSpartina alterniflora1
Authors: Kocsis Michael G. , Nolte Kurt D. , Rhodes David , Shen Tun-Li , Gage Douglas A. , Hanson Andrew D.
Published: July 2002

The osmoprotectant 3-dimethylsulfoniopropionate (DMSP) occurs in Gramineae and Compositae, but its synthesis has been studied only in the latter. The DMSP synthesis pathway was therefore investigated in the salt marsh grassSpartina alterniflora Loisel. Leaf tissue metabolized supplied [35S]methionine (Met) toS-methyl-l-Met (SMM), 3-dimethylsulfoniopropylamine (DMSP-amine), and DMSP. The35S-labeling kinetics of SMM and DMSP-amine indicated that they were intermediates and, consistent with this, the dimethylsulfonium moiety of SMM was shown by stable isotope labeling to be incorporated as a unit into DMSP. The identity of DMSP-amine, a novel natural product, was confirmed by both chemical and mass-spectral methods. S. alterniflora readily converted supplied [35S]SMM to DMSP-amine and DMSP, and also readily converted supplied [35S]DMSP-amine to DMSP; grasses that lack DMSP did neither. A small amount of label was detected in 3-dimethylsulfoniopropionaldehyde (DMSP-ald) when [35S]SMM or [35S]DMSP-amine was given. These results are consistent with the operation of the pathway Met → SMM → DMSP-amine → DMSP-ald → DMSP, which differs from that found in Compositae by the presence of a free DMSP-amine intermediate. This dissimilarity suggests that DMSP synthesis evolved independently in Gramineae and Compositae.
High Aluminum Resistance in Buckwheat1
Authors: Ma Jian Feng , Hiradate Syuntaro , Matsumoto Hideaki
Published: July 2002

Buckwheat (Fagopyrum esculentum Moench. cv Jianxi), which shows high Al resistance, accumulates Al in the leaves. The internal detoxification mechanism was studied by purifying and identifying Al complexes in the leaves and roots. About 90% of Al accumulated in the leaves was found in the cell sap, in which the dominant organic acid was oxalic acid. Purification of the Al complex in the cell sap of leaves by molecular-sieve chromatography resulted in a complex with a ratio of Al to oxalic acid of 1:3. A 13C-nuclear magnetic resonance study of the purified cell sap revealed only one signal at a chemical shift 164.4 ppm, which was assigned to the Al-chelated carboxylic group of oxalic acid. A 27Al-nuclear magnetic resonance analysis revealed one major signal at the chemical shift of 16.0 to 17.0 ppm, with a minor signal at the chemical shift of 11.0 to 12 ppm in both the intact roots and their cell sap, which is consistent with the Al-oxalate complexes at 1:3 and 1:2 ratios, respectively. The purified cell sap was not phytotoxic to root elongation in corn (Zea mays). All of these results indicate that Al tolerance in the roots and leaves of buckwheat is achieved by the formation of a nonphytotoxic Al-oxalate (1:3) complex.
Molecular Characterization of an Arabidopsis Gene Encoding Hydroperoxide Lyase, a Cytochrome P-450 That Is Wound Inducible1
Authors: Bate Nicholas J. , Sivasankar Sobhana , Moxon Claire , Riley John M.C. , Thompson John E. , Rothstein Steven J.
Published: July 2002

Hydroperoxide lyase (HPL) cleaves lipid hydroperoxides to produce volatile flavor molecules and also potential signal molecules. We have characterized a gene from Arabidopsis that is homologous to a recently cloned HPL from green pepper (Capsicum annuum). The deduced protein sequence indicates that this gene encodes a cytochrome P-450 with a structure similar to that of allene oxide synthase. The gene was cloned into an expression vector and expressed in Escherichia coli to demonstrate HPL activity. Significant HPL activity was evident when 13S-hydroperoxy-9(Z),11(E),15(Z)-octadecatrienoic acid was used as the substrate, whereas activity with 13S-hydroperoxy-9(Z),11(E)-octadecadienoic acid was approximately 10-fold lower. Analysis of headspace volatiles by gas chromatography-mass spectrometry, after addition of the substrate to E. coli extracts expressing the protein, confirmed enzyme-activity data, since cis-3-hexenal was produced by the enzymatic activity of the encoded protein, whereas hexanal production was limited. Molecular characterization of this gene indicates that it is expressed at high levels in floral tissue and is wound inducible but, unlike allene oxide synthase, it is not induced by treatment with methyl jasmonate.
A Steep Dependence of Inward-Rectifying Potassium Channels on Cytosolic Free Calcium Concentration Increase Evoked by Hyperpolarization in Guard Cells1
Authors: Grabov Alexander , Blatt Michael R.
Published: July 2002

Inactivation of inward-rectifying K+ channels (IK,in) by a rise in cytosolic free [Ca2+] ([Ca2+]i) is a key event leading to solute loss from guard cells and stomatal closure. However, [Ca2+]i action onIK,in has never been quantified, nor are its origins well understood. We used membrane voltage to manipulate [Ca2+]i (A. Grabov and M.R. Blatt [1998] Proc Natl Acad Sci USA 95: 4778–4783) while recordingIK,in under a voltage clamp and [Ca2+]i by Fura-2 fluorescence ratiophotometry. IK,in inactivation correlated positively with [Ca2+]i and indicated a Ki of 329 ± 31 nm with cooperative binding of four Ca2+ ions per channel. IK,in was promoted by the Ca2+ channel antagonists Gd3+ and calcicludine, both of which suppressed the [Ca2+]i rise, but the [Ca2+]i rise was unaffected by the K+ channel blocker Cs+. We also found that ryanodine, an antagonist of intracellular Ca2+ channels that mediate Ca2+-induced Ca2+ release, blocked the [Ca2+]i rise, and Mn2+quenching of Fura-2 fluorescence showed that membrane hyperpolarization triggered divalent release from intracellular stores. These and additional results point to a high signal gain in [Ca2+]i control ofIK,in and to roles for discrete Ca2+ flux pathways in feedback control of the K+ channels by membrane voltage.
NADH-Glutamate Synthase in Alfalfa Root Nodules. Genetic Regulation and Cellular Expression1
Authors: Trepp Gian B. , van de Mortel Martijn , Yoshioka Hirofumi , Miller Susan S. , Samac Deborah A. , Gantt J. Stephen , Vance Carroll P.
Published: July 2002

NADH-dependent glutamate synthase (NADH-GOGAT; EC 1.4.1.14) is a key enzyme in primary nitrogen assimilation in alfalfa (Medicago sativa L.) root nodules. Here we report that in alfalfa, a single gene, probably with multiple alleles, encodes for NADH-GOGAT. In situ hybridizations were performed to assess the location of NADH-GOGAT transcript in alfalfa root nodules. In wild-type cv Saranac nodules theNADH-GOGAT gene is predominantly expressed in infected cells. Nodules devoid of bacteroids (empty) induced bySinorhizobium meliloti 7154 had no NADH-GOGAT transcript detectable by in situ hybridization, suggesting that the presence of the bacteroid may be important for NADH-GOGAT expression. The pattern of expression of NADH-GOGAT shifted during root nodule development. Until d 9 after planting, all infected cells appeared to express NADH-GOGAT. By d 19, a gradient of expression from high in the early symbiotic zone to low in the late symbiotic zone was observed. In 33-d-old nodules expression was seen in only a few cell layers in the early symbiotic zone. This pattern of expression was also observed for the nifH transcript but not for leghemoglobin. The promoter of NADH-GOGAT was evaluated in transgenic alfalfa plants carrying chimeric β-glucuronidase promoter fusions. The results suggest that there are at least four regulatory elements. The region responsible for expression in the infected cell zone contains an 88-bp direct repeat.
Slow and Prolonged Activation of the p47 Protein Kinase during Hypersensitive Cell Death in a Culture of Tobacco Cells
Authors: Suzuki Kaoru , Yano Akira , Shinshi Hideaki
Published: July 2002

To investigate the involvement of protein kinases in the signaling cascade that leads to hypersensitive cell death, we used a previously established system in which a fungal elicitor, xylanase from Trichoderma viride (TvX), induces a hypersensitive reaction in tobacco (Nicotiana tabacum) cells in culture (line XD6S). The elicitor induced the slow and prolonged activation of a p47 protein kinase, which has the characteristics of a family member of the mitogen-activated protein kinases. An inhibitor of protein kinases, staurosporine, and a blocker of Ca channels, Gd3+ ions, both of which blocked the TvX-induced hypersensitive cell death, inhibited the TvX-induced activation of p47 protein kinase. Moreover, an inhibitor of serine/threonine protein phosphatase alone induced both rapid cell death and the persistent activation of the p47 protein kinase. Thus, the p47 protein kinase might be a component of the signal transduction pathway that leads to hypersensitive cell death, and the regulation of the duration of activation of the p47 protein kinase might be important in determining the destiny of tobacco cells.
Enhanced Expression and Activation of the Alternative Oxidase during Infection of Arabidopsis withPseudomonas syringae pv tomato1
Authors: Simons Bert H. , Millenaar Frank F. , Mulder Lonneke , Van Loon Leendert C. , Lambers Hans
Published: July 2002

Cyanide-resistant (“alternative”) respiration was studied in Arabidopsis during incompatible and compatible infection with Pseudomonas syringae pv tomato DC3000. Total leaf respiration increased as the leaves became necrotic, as did the cyanide-resistant component that was sensitive to salicylhydroxamic acid. Infiltration of leaves with an avirulent strain rapidly induced alternative oxidase (AOX) mRNA, whereas the increase was delayed in the compatible combination. The increase in mRNA correlated with the increase in AOX protein. Increased expression was confined to the infected leaves, in contrast to the pathogenesis-related protein-1, which was induced systemically. Virtually all of the AOX protein was in the reduced (high-activity) form. Using transgenic NahG and mutantnpr1-1 and etr1-1 plants, we established that the rapid induction of the AOX was associated with necrosis and that ethylene, but not salicylic acid, was required for its induction. Increased pyruvate levels in the infected leaves suggested that increased substrate levels were respired through the alternative pathway; however, in the control leaves and the infected leaves, respiration was not inhibited by salicylhydroxamic acid alone. Increased respiration appeared to be associated primarily with symptom expression rather than resistance reactions.
Aldehyde Oxidase and Xanthine Dehydrogenase in aflacca Tomato Mutant with Deficient Abscisic Acid and Wilty Phenotype1
Authors: Sagi Moshe , Fluhr Robert , Lips S. Herman
Published: July 2002

The flacca tomato (Lycopersicon esculentum) mutant displays a wilty phenotype as a result of abscisic acid (ABA) deficiency. The Mo cofactor (MoCo)-containing aldehyde oxidases (AO; EC 1.2.3.1) are thought to play a role in the final oxidation step required for ABA biosynthesis. AO and related MoCo-containing enzymes xanthine dehydrogenase (XDH; EC 1.2.1.37) and nitrate reductase (EC 1.6.6.1) were examined in extracts of the flacca tomato genotype and of wild-type (WT) roots and shoots. The levels of MoCo were found to be similar in both genotypes. No significant XDH or AO (MoCo-containing hydroxylases) activities were detected inflacca leaves; however, the mutant exhibited considerable MoCo-containing hydroxylase activity in the roots, which contained notable amounts of ABA. Native western blots probed with an antibody to MoCo-containing hydroxylases revealed substantial, albeit reduced, levels of cross-reactive protein in the flaccamutant shoots and roots. The ABA xylem-loading rate was significantly lower than that in the WT, indicating that the flacca is also defective in ABA transport to the shoot. Significantly, in vitro sulfurylation with Na2S reactivated preexisting XDH and AO proteins in extracts from flacca, particularly from the shoots, and superinduced the basal-level activity in the WT extracts. The results indicate that in flacca,MoCo-sulfurylase activity is impaired in a tissue-dependent manner.