bluuebunny/crossref_metadata_2025 huggingface dataset:
Ultrasonography of the uterine cervix and preterm delivery
Authors: Hiilesmaa Vilho , Taipale Pekka
Published: July 2002

The incidence of premature delivery (at less than 37 completed weeks) has been stable at between 5–10% of deliveries over the past 20 years despite intensive research in this field. Preterm delivery is a major cause of perinatal morbidity and mortality. The identification of women at increased risk for this condition has traditionally been based on clinical history (e.g. previous premature birth or second-trimester miscarriage), digital evaluation of the cervix and the occurrence of uterine contractions.
Primary culture of porcine PGCs requires LIF and porcine membrane-bound stem cell factor
Authors: Durcova-Hills Gabriela , Prelle Katja , Müller Sigrid , Stojkovic Miodrag , Motlik Jan , Wolf Eckhard , Brem Gottfried
Published: July 2002

We studied the effect of murine leukaemia inhibitory factor (LIF), human basic fibroblast growth factor (bFGF) and porcine stem cell factor (SCF) on the survival and/or proliferation of porcine primordial germ cells (PGCs) obtained from 27-day-old embryos in vitro. PGCs were cultured in embryonic stem cell (ESC) medium supplemented with or without either LIF (1000 IU/ml) alone or LIF together with bFGF (10 ng/ml). They were seeded on mitotically inactivated feeder cells, either STO or transfected STO cells (STO#8), expressing the membrane-bound form of porcine SCF. PGCs were identified by their alkaline phosphatase (AP) activity and counted after 1, 3 and 5 days in culture. After 1 day of culture, PGCs cultured on STO#8 cells showed significantly higher survival than PGCs cultured on STO cells (p < 0.05). The combined effect of SCF and LIF caused a significant increase in PGC number by day 3 of culture when PGCs were cultured on either STO cells (p < 0.01) or STO#8 (p < 0.001). When SCF and LIF were used together with bFGF no increase in the PGC number was observed. Our results suggest that the membrane-bound form of porcine SCF plays a pivotal role in the primary culture of porcine PGCs and that bFGF is not required in vitro.
CULTURAL CAPITAL AND THE SCENE OF RIOTING: MALE WORKING-CLASS AUTHORSHIP IN ALTON LOCKE
Authors: Menke Richard
Published: July 2002

IN ITS VERY TITLE, Charles Kingsley’s 1850 novel Alton Locke, Tailor and Poet: An Autobiography hints at a set of questions that the novel itself never manages to answer in a very clear or convincing way: what is the relationship between manual and intellectual labor, between industrial and poetic production, between making a coat and writing a poem? How might the early Victorian imagination conceive of a working tailor who is also a working poet — especially in light of the various actual working-class poets who appeared on the literary scene in the first half of the nineteenth-century, complete with occupational epithets, such as Thomas Cooper, the “shoe-maker poet” (a figure who in many ways provided a model for Kingsley’s fictional protagonist)? And what if, like a fair number of urban artisans, including Cooper himself, the tailor-poet is also a Chartist — as Alton Locke indeed turns out to be? What is the relationship between the Chartist call for reform and for representation of disenfranchised men in the political realm, and the attempts of a fictional working-class man (since the novel’s treatment of gender, as I will argue, is crucial to its treatment of politics and culture) to enter the early Victorian field of literary production? Or why, in the first place, should a novel that treats the “social problem” of class in the hungry forties and the appalling working conditions of the clothes trade do so by way of the literary aspirations of its title character, that is, through a fictional construction of working-class authorship?
PEKING PLOTS: FICTIONALIZING THE BOXER REBELLION OF 1900
Authors: Forman Ross G.
Published: July 2002

“A handful of foreigners have shown China what they can do against murderous thousands, and it only remains for the Powers to stamp the lesson deeper, and exact punishment for the guilty and full compensation for losses sustained.”

— W. Murray Graydon, The Perils of Pekin (1904)

“To find something akin in its savage barbarity you must go back to Lucknow, where a mixed multitude shut up in the Residency were holding out against fearful odds in expectation of relief by Havelock’s Highlanders, resolved to perish of starvation rather than surrender, for the fate of Cawnpore stared them in the face. “It adds point to this parallel to remember that the Tartar rulers of China are cousin german to the Great Moghul who headed the Sepoy Mutiny. “It was some excuse for the King of Delhi that he was seeking to regain his throne. No such apology can be offered for the Empress Dowager of China. She has made war not without provocation, but wholly unjustifiable, on all nations of the civilized world.”

— W. A. P. Martin, The Siege in Peking (1900)

THIS ESSAY REVIEWS THE LITERARY PRODUCTION — primarily adventure novels, and several of them bestsellers — centered around the events of the 1900 Boxer Rebellion, in which a Chinese “secret society,” with the collusion of certain Manchu authorities, carried out a systematic attempt to annihilate all Westerners and “native Christians” living in China.1 The Boxers, so-called because their “superstitious” practices looked like magic boxing, swept across North China from the spring of 1900, eventually throwing much of the imperial capital of Peking (Beijing) into confusion.2 Forced to hole up in the Legations and other barricaded areas, the Westerners of the region joined forces under largely British leadership and fought against incredible odds to protect themselves, holding out until an international resistance force, led by the British, rescued them fifty-five days later, and the Rebellion subsided.3 Important as a turning point in Chinese international relations and as a mark of the increasing weakness of the central authority of the Middle Kingdom, the Boxer Rebellion served an even more important function with regard to British conceptualizations of the empire in its formal and informal forms. It threw into question non-interventionist trade strategies and underscored the tenuous nature of imperial authority both in formal colonies such as India (where fledgling nationalist movements were evolving) and in areas bordering on these formal colonies and largely dominated through foreign authority. (The central Chinese government, for instance, though not dependent on imports and loans to any great degree, at this point gathered all of its significant income from the British-led Imperial Maritime Customs Service.)
Appendix: Definitions of typed feature structures
Authors: COPESTAKE ANN
Published: July 2002

The LinGO grammar consists of a specification of a type system and of various typed
feature structures which are well-formed according to the type system. The typed
feature structures function as grammar rules, lexical rules and lexical entries. There
are several variant typed feature structure formalisms, with different computational
properties, so in this appendix we very briefly specify the version assumed by the
LinGO grammar.

This appendix is necessarily terse, and is only intended to allow a reader who
already has a knowledge of typed feature structures to understand the specific
formalism used in the LinGO grammar. The definitions given below basically follow
Carpenter (1992), with the notion of type constraint from Copestake (1992). For
formal details of typed feature structures in general see Carpenter (1992). A detailed
account of the specific assumptions made here is given in Copestake (1999) (See
Chapter 4 for an introduction, and Chapter 5 for a semi-formal account.)

Note that the LinGO grammar uses a very restricted formalism. For instance,
it does not utilize disjunctive feature structures, negation, implication, inequalities,
defaults, set-valued features, extensionality or relational constraints. Constraint resolution does not require that every type be made maximally specific, and the type
inference system is essentially non-recursive. The recursive power necessary in grammars is explicitly encoded via rules, which are expressed as typed feature structures,
but interpreted as phrase structure rules.
Uniform knowledge representation for language processing in the B2
system
Authors: MCROY SUSAN W. , ALI SYED S. , HALLER SUSAN M.
Published: July 2002

We describe the natural language processing and knowledge representation

components of B2, a collaborative system that allows medical students
to practice their decision-making skills by
considering a number of medical cases that differ from each other in a
controlled manner. The
underlying decision-support model of B2 uses a Bayesian network that captures
the results
of prior clinical studies of abdominal pain. B2 generates story-problems
based on this model
and supports natural language queries about the conclusions of the model
and the reasoning
behind them. B2 benefits from having a single knowledge representation
and reasoning
component that acts as a blackboard for intertask communication and cooperation.
All
knowledge is represented using a propositional semantic network formalism,
thereby providing
a uniform representation to all components. The natural language
component is composed
of a generalized augmented transition network parser/grammar and a
discourse analyzer
for managing the natural language interactions. The knowlege representation
component
supports the natural language component by providing a uniform representation
of the
content and structure of the interaction, at the parser, discourse, and
domain levels. This
uniform representation allows distinct tasks, such as dialog management,
domain-specific
reasoning, and meta-reasoning about the Bayesian network, to all use the
same information
source, without requiring mediation. This is important because there are
queries, such as
Why?, whose interpretation and response requires information from

each of these tasks. By contrast, traditional approaches treat each subtask

as a “black-box” with respect to other
task components, and have a separate knowledge representation language
for each. As a
result, they have had much more difficulty providing useful responses.
Understanding pronominal references to
quantified expressions
Authors: TURNER ELISE H. , MATTHIAS COLLETTE M.
Published: July 2002

Quantified expressions present an interesting case for understanding pronominal reference
because the quantifier which appears in the expression affects how the pronoun will be
understood. The quantifier determines which sets will be placed in focus and predicts the
relation between the sentence containing the quantifier and the following sentence (Moxey
and Sanford 1993a). This information is essential to understanding the pronominal reference.
In this paper, we discuss how a natural language processing system can take advantage of
this information to understand pronominal references to quantified expressions.
AN INVESTIGATION INTO THE PSYCHOMETRIC PROPERTIES OF THE COGNITIVE THERAPY SCALE FOR PSYCHOSIS (CTS-Psy)
Authors: Haddock Gillian , Devane Sheila , Bradshaw Tim , McGovern John , Tarrier Nicholas , Kinderman Peter , Baguley Ian , Lancashire Stuart , Harris Neil
Published: July 2002

Recent research suggests that cognitive-behaviour therapy (CBT) can significantly improve outcomes for
patients with severe mental health problems. However, there are no tools specifically designed to assess competence
in delivering CBT to psychotic patients. This study investigates the psychometric properties of the Cognitive Therapy
Scale for Psychosis (the CTS-Psy) for assessing the quality of CBT with psychotic patients. Inter-rater reliability of
trained raters using the CTS-Psy was investigated using taped therapy of trainees engaged in a CBT oriented psychosis
training course. Validity was investigated in relation to examining the degree to which the scale could be used to
assess a range of therapist ability and patient severity and by assessing the degree to which the CTS-Psy could pick
up changes in skill acquisition during the training course over a 9-month period. The CTS-Psy demonstrated excellent
inter-rater reliability and good validity in relation to it being able to rate all standards of therapy and all types of
patient sessions in the sample studied. In addition, the scale was sensitive to changes in clinical skills during a training
course and could discriminate between those who had received training and those who had not.
Looking for Funding in All the Right Places
Authors: Lezak Anne D.
Published: July 2002

The aim of this compact, well-organized volume is to guide
the hopeful brain and behavioral sciences researcher through
the entire proposal and funding process, from conceptualizing
an initial project idea all the way to preparation of final
reports and competing renewal applications. Particularly
for the novice grant-seeker, this volume is a useful aid
to cracking the often mystifying world of research funding
opportunities.
A view of computer music from New Zealand: Auckland, Waikato and the Asia/Pacific connection
Authors: Dart William , Elmsly John , Whalley Ian
Published: July 2002

Dealing predominantly with ‘art music’ aspects of electroacoustic music practice, this paper looks at cultural, aesthetic,
environmental and technical influences on current and emerging practices from the upper half of the North Island of
New Zealand. It also discusses the influences of Asian and Pacific cultures on the idiom locally. Rather than dwell on
the similarities with current international styles, the focus is largely on some of the differences.
Martin Herbert
Authors: Cox Antony
Published: July 2002

Martin Herbert is very widely known, not
just amongst his fellow clinical psychologists,
but amongst a broad spectrum of
professionals and parents in many countries.
His reputation springs not just from
his teaching and writing, but from his
activities across professional boundaries
and his commitment to direct work with
children and families. In his own profession
he has held chairs in Clinical Psychology in
Leicester and Exeter Universities where he
set up doctoral clinical psychology courses,
at Leicester in the 1980s and in Devon in
the 1990s. As Professor of Social Work in
Leicester from 1975 to 1982 he was the last
senior academic in that field who was not a
social worker. Despite heavy loads he has
developed and implemented very carefully
articulated programmes for the assessment
and treatment of children, particularly
those with oppositional, aggressive and
anxious behaviour. Maintenance of his
own personal participation has been axiomatic.
He has carried his skills and knowledge
into many different contexts, including
those concerned with adults, but has
derived especial enjoyment from work with
paediatricians and children with disabilities.
He has been Chair of two ACPP
branches, East Midlands and South West.
Commentary: Evidence-Based Child and Adolescent Mental Health Services
Authors: Harrington Richard
Published: July 2002

The argument for evidence-based child and adolescent
mental health services is irresistible. Indeed, I have yet to
meet a mental health practitioner who has told me that his
or her work was not based on evidence. The exam
question, however, is ‘what is the best evidence?’ In a
helpful contribution to the current debate about evidence-based practice, Ramchandani, Joughin and Zwi point out
that the answer depends on what the question was in the
first place. They argue that while some clinical questions
are best tackled using quantitative methods such as
randomised trials, other questions are better answered
using different techniques. Traditional hierarchies of
evidence that give primacy to randomised trials may not
always be appropriate to child mental health practice.
Informality and Institutional Inertia: the Case of Japanese Financial Regulation
Authors: Amyx Jennifer A.
Published: July 2002

This article examines the case of institutional inertia in Japanese financial regulation, focusing on the reasons why institutions centered on informal modes of organization and interaction proved particularly ‘sticky.’ The Japanese case serves as a particularly tough test for theories of institutional adaptation and change because even crisis – a time when the costs of inaction tend to far exceed the benefits – failed to produce timely institutional change. The paper argues that informal, exclusionary and opaque relational ties served as a functional substitute for formal regulation and promoted cooperative government-bank relationships in an earlier period. Yet, when the informal attributes of the system began to impede the sound functioning of the financial system, the very opacity of these ties and the informational dynamics underlying them meant that the Diet and the general public were less than fully aware of the extent of dysfunction present as time went on.
Head and trunk in zebrafish arise via coinhibition of BMP signaling by bozozok and chordino
Authors: Gonzalez Encina M. , Fekany-Lee Kimberly , Carmany-Rampey Amanda , Erter Caroline , Topczewski Jacek , Wright Christopher V.E. , Solnica-Krezel Lilianna
Published: July 2002

Spatial variations in the levels of bone morphogenetic protein (BMP) signaling are a critical determinant of dorsoanterior-ventroposterior pattern in vertebrate embryos. Whereas BMP overexpression abolishes both head and trunk development, known single and double loss-of-function mutations in BMP inhibitors have less dramatic effects. We report that combining mutations in the zebrafish genes bozozok and chordino causes a synergistic loss of head and trunk, whereas most cells express ventro-posterior markers and develop into a tail. Genetic inactivation of BMP signaling fully suppresses these defects. Thus, a remarkably simple genetic mechanism, involving a coinhibition of BMP function by the partially overlapping bozozok and chordino pathways is used to specify vertebrate head and trunk.
The lac operator-repressor system is functional in the mouse
Authors: Cronin Carolyn A. , Gluba Wendy , Scrable Heidi
Published: July 2002

We report the successful transfer of a fully functionallac operator-repressor gene regulatory system to the mouse. The key component is a lac repressor transgene that resembles a typical mammalian gene both in codon usage and structure and expresses functional levels of repressor protein in the animal. We used the repressor to regulate the expression of a mammalian reporter gene consisting of the tyrosinase promoter embedded with three shortlac operator sequences and the tyrosinase coding sequence. Pigmentation of the mouse was controlled by the interaction of thelac repressor with the regulatable Tyrosinase transgene in a manner that was fully reversible by the lactose analog IPTG. Direct control of mammalian promoters by the lac repressor provides tight, reversible regulation, predictable levels of de-repressed expression, and the promise of reversible control of the endogenous genome.
Mzf1 controls cell proliferation and tumorigenesis
Authors: Gaboli Mirella , Kotsi Paraskevi A. , Gurrieri Carmela , Cattoretti Giorgio , Ronchetti Simona , Cordon-Cardo Carlos , Broxmeyer Hal E. , Hromas Robert , Pandolfi Pier Paolo
Published: July 2002

MZF1 is a transcription factor belonging to theKrüppelfamily of zinc finger proteins, expressed in totipotent hemopoietic cells as well as in myeloid progenitors. Here we have inactivatedMzfi1by gene targeting.Mzf1−/−mice develop lethal neoplasias characterized by the infiltration and complete disruption of the liver architecture by a monomorphic population of cells of myeloid origin reminiscent of human chloromas.Mzf1inactivation results in a striking increase of the autonomous cell proliferation and of the ability ofMzf1−/−hemopoietic progenitors to sustain long-term hemopoiesis. These findings demonstrate that Mzf1 can act as a tumor/growth suppressor in the hemopoietic compartment.
Multiple LTR-Retrotransposon Families in the Asexual Yeast Candida albicans
Authors: Goodwin Timothy J.D. , Poulter Russell T.M.
Published: July 2002

We have begun a characterization of the long terminal repeat (LTR) retrotransposons in the asexual yeast Candida albicans. A database of assembled C. albicans genomic sequence at Stanford University, which represents 14.9 Mb of the 16-Mb haploid genome, was screened and >350 distinct retrotransposon insertions were identified. The majority of these insertions represent previously unrecognized retrotransposons. The various elements were classified into 34 distinct families, each family being similar, in terms of the range of sequences that it represents, to a typical Ty element family of the related yeast Saccharomyces cerevisiae. These C. albicans retrotransposon families are generally of low copy number and vary widely in coding capacity. For only three families, was a full-length and apparently intact retrotransposon identified. For many families, only solo LTRs and LTR fragments remain. Several families of highly degenerate elements appear to be still capable of transposition, presumably via trans-activation. The overall structure of the retrotransposon population in C. albicans differs considerably from that of S. cerevisiae. In that species, retrotransposon insertions can be assigned to just five families. Most of these families still retain functional examples, and they generally appear at higher copy numbers than the C. albicans families. The possibility that these differences between the two species are attributable to the nonstandard genetic code of C. albicans or the asexual nature of its genome is discussed. A region rich in retrotransposon fragments, that lies adjacent to many of theCARE-2/Rel-2 sub-telomeric repeats, and which appears to have arisen through multiple rounds of duplication and recombination, is also described.

[The sequence data described in this paper have been submitted to the GenBank data library. Accession numbers are listed in Table 1 and in the Materials and Methods section.]
Centromere Repositioning
Authors: Montefalcone Giuseppe , Tempesta Sergio , Rocchi Mariano , Archidiacono Nicoletta
Published: July 2002

Primate pericentromeric regions recently have been shown to exhibit extraordinary evolutionary plasticity. In this paper we report an additional peculiar feature of these regions that we discovered while analyzing, by FISH, the evolutionary conservation of primate phylogenetic chromosome IX. If the position of the centromere is not taken into account, a relatively small number of rearrangements must be invoked to account for interspecific differences. Conversely, if the centromere is included, a paradox emerges: The position of the centromere seems to have undergone, in some species, an evolutionary history independent from the surrounding markers. A significant number of additional rearrangements must be proposed to reconcile the order of the markers with centromere position. Alternatively, the evolutionary emergence of neocentromeres can be postulated.
Sulfur Availability and the SAC1 Gene Control Adenosine Triphosphate Sulfurylase Gene Expression in Chlamydomonas reinhardtii
Authors: Yildiz F. H. , Davies J. P. , Grossman A.
Published: July 2002

A Chalmydomonas reinhardtii adenosine triphosphate (ATP) sulfurylase cDNA clone (pATS1) was selected by complementing a mutation in the ATP sulfurylase gene (cysD) of Escherichia coli. E. coli cysD strains harboring pATS1 grow on medium containing sulfate as the sole sulfur source and exhibit ATP sulfurylase activity. The amino acid sequence of the C. reinhardtii ATP sulfurylase, derived from the nucleotide sequence of the complementing gene (ATS1), is 25 to 40% identical to that of ATP sulfurylases in other eukaryotic organisms and has a putative transit peptide at its amino terminus. ATP sulfurylase mRNA was present when cells were grown in sulfur-replete medium, but accumulated to higher levels when the cells were exposed to sulfur-limiting conditions. Furthermore, sulfur-stress-induced accumulation of the ATS1 transcript was reduced in a strain defective in SAC1, a gene that is critical for acclimation to sulfur-limited growth.
Molecular Cloning of 4-Coumarate:Coenzyme A Ligase in Loblolly Pine and the Roles of This Enzyme in the Biosynthesis of Lignin in Compression Wood
Authors: Zhang X. H. , Chiang V. L.
Published: July 2002

Two genomic sequences encoding 4-coumarate:coenzyme A ligase (4CL;EC 6.2.1.12) in loblolly pine (Pinus taeda L.) were cloned. Both sequences contained three introns and four exons with identical coding sequences predicting 537 amino acids. Two of the three introns in these two clones were different both in sequence and in length. Sequences of both 4CL clones were found in all nine megagametophyte DNAs tested, providing genetic evidence that these two 4CL genomic sequences are nonallelic genes. Our analyses suggest that there are at least two distinct, intron-containing 4CL genes, at least one of which is transcribed into 4CL mRNA in developing xylem tissue of loblolly pine. The levels of 4CL gene transcription in xylem were influenced by compressional stress, resulting in an elevated 4CL enzyme activity with 4-coumaric acid. 4CL enzyme activity with ferulic acid remained unchanged, whereas with caffeic acid it was significantly inhibited. Exogenously applied trans-cinnamic acid in the protein extracts from normal wood xylem caused inhibition of 4CL activity toward caffeic acid similar to that under compressional stress. The implications of this cinnamic acid-modulated effect on 4CL enzyme activities toward different substrates in regulating monolignol synthesis in xylem under compressional stress are discussed.
Characterization of a New Antifungal Chitin-Binding Peptide from Sugar Beet Leaves
Authors: Nielsen K. K. , Nielsen J. E. , Madrid S. M. , Mikkelsen J. D.
Published: July 2002

The intercellular washing fluid (IWF) from leaves of sugar beet (Beta vulgaris L.) contains a number of proteins exhibiting in vitro antifungal activity against the devastating leaf pathogen Cercospora beticola (Sacc.). Among these, a potent antifungal peptide, designated IWF4, was identified. The 30-amino-acid residue sequence of IWF4 is rich in cysteines (6) and glycines (7) and has a highly basic isoelectric point. IWF4 shows homology to the chitin-binding (hevein) domain of chitin-binding proteins, e.g. class I and IV chitinases. Accordingly, IWF4 has a strong affinity to chitin. Notably, it binds chitin more strongly than the chitin-binding chitinases. A full-length IWF4 cDNA clone was obtained that codes for a preproprotein of 76 amino acids containing an N-terminal putative signal peptide of 21 residues, followed by the mature IWF4 peptide of 30 residues, and an acidic C-terminal extension of 25 residues. IWF4 mRNA is expressed in the aerial parts of the plant only, with a constitutive expression in young and mature leaves and in young flowers. No induced expression of IWF4 protein or mRNA was detected during infection with C. beticola or after treatment with 2,6-dichloroisonicotinic acid, a well-known inducer of resistance in plants.
Characterization and Expression of NAD(H)-Dependent Glutamate Dehydrogenase Genes in Arabidopsis
Authors: Turano F. J. , Thakkar S. S. , Fang T. , Weisemann J. M.
Published: July 2002

Two distinct cDNA clones encoding NAD(H)-dependent glutamate dehydrogenase (NAD[H]-GDH) in Arabidopsis thaliana were identified and sequenced. The genes corresponding to these cDNA clones were designated GDH1 and GDH2. Analysis of the deduced amino acid sequences suggest that both gene products contain putative mitochondrial transit polypeptides and NAD(H)- and α--ketoglutarate-binding domains. Subcellular fractionation confirmed the mitochondrial location of the NAD(H)-GDH isoenzymes. In addition, a putative EF-hand loop, shown to be associated with Ca2+ binding, was identified in the GDH2 gene product but not in the GDH1 gene product. GDH1 encodes a 43.0-kD polypeptide, designated α-, and GDH2 encodes a 42.5-kD polypeptide, designated [beta]. The two subunits combine in different ratios to form seven NAD(H)-GDH isoenzymes. The slowest-migrating isoenzyme in a native gel, GDH1, is a homohexamer composed of α- subunits, and the fastest-migrating isoenzyme, GDH7, is a homohexamer composed of [beta] subunits. GDH isoenzymes 2 through 6 are heterohexamers composed of different ratios of α- and [beta] subunits. NAD(H)-GDH isoenzyme patterns varied among different plant organs and in leaves of plants irrigated with different nitrogen sources or subjected to darkness for 4 d. Conversely, there were little or no measurable changes in isoenzyme patterns in roots of plants treated with different nitrogen sources. In most instances, changes in isoenzyme patterns were correlated with relative differences in the level of α- and [beta] subunits. Likewise, the relative difference in the level of α- or [beta] subunits was correlated with changes in the level of GDH1 or GDH2 transcript detected in each sample, suggesting that NAD(H)-GDH activity is controlled at least in part at the transcriptional level.
Cellulose and Callose Biosynthesis in Higher Plants (I. Solubilization and Separation of (1->3)- and (1->4)-β-Glucan Synthase Activities from Mung Bean)
Authors: Kudlicka K. , Brown Jr R. M.
Published: July 2002

(1->3)- and (1->4)-β-glucan synthase activities from higher plants have been physically separated by gel electrophoresis in nondenaturing conditions. The two glucan synthases show different mobilities in native polyacrylamide gels. Further separation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed a different polypeptide composition in these synthases. Three polypeptides (64, 54, and 32 kD) seem to be common to both synthase activities, whereas two polypeptides (78 and 38 kD) are associated only with callose synthase activity. Twelve polypeptides (170, 136, 108, 96, 83, 72, 66, 60, 52, 48, 42, and 34 kD) appear to be specifically associated with cellulose synthase activity. The successful separation of (1->3)- and (1->-4)-β-glucan synthase activities was based on the manipulation of digitonin concentrations used in the solubilization of membrane proteins. At low dipitomin concentrations (0.05 and 0.1%), the ratio of the cellulose to callose synthase activity was higher. At higher digitonin (0.5–1%) concentrations, the ratio of the callose to cellulose synthase activity was higher. Rosette-like particles with attached product were observed in samples taken from the top of the stacking gel, where only cellulose was synthesized. Smaller (nonrosette) particles were found in the running gel, where only callose was synthesized. These findings suggest that a higher level of subunit organization is required for in vitro cellulose synthesis in comparison with callose assembly.
The Intracellular Localization of Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase in Chlamydomonas reinhardtii1
Authors: Borkhsenious Olga N. , Mason Catherine B. , Moroney James V.
Published: July 2002

The pyrenoid is a proteinaceous structure found in the chloroplast of most unicellular algae. Various studies indicate that ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is present in the pyrenoid, although the fraction of Rubisco localized there remains controversial. Estimates of the amount of Rubisco in the pyrenoid of Chlamydomonas reinhardtiirange from 5% to nearly 100%. Using immunolocalization, the amount of Rubisco localized to the pyrenoid or to the chloroplast stroma was estimated for C. reinhardtii cells grown under different conditions. It was observed that the amount of Rubisco in the pyrenoid varied with growth condition; about 40% was in the pyrenoid when the cells were grown under elevated CO2 and about 90% with ambient CO2. In addition, it is likely that pyrenoidal Rubisco is active in CO2 fixation because in vitro activity measurements showed that most of the Rubisco must be active to account for CO2-fixation rates observed in whole cells. These results are consistent with the idea that the pyrenoid is the site of CO2 fixation in C. reinhardtii and other unicellular algae containing CO2-concentrating mechanisms.
Multiple Genes Encoding the Conserved CCAAT-Box Transcription Factor Complex Are Expressed in Arabidopsis
Authors: Edwards David , Murray James A.H. , Smith Alison G.
Published: July 2002

The CCAAT motif is found in the promoters of many eukaryotic genes. In yeast a single complex of three proteins, termed HAP2, HAP3, and HAP5, binds to this sequence, and in mammals the three components of the equivalent complex (called variously NF-Y, CBF, or CP1) are also represented by single genes. Here we report the presence of multiple genes for each of the components of the CCAAT-binding complex, HAP2,3,5, from Arabidopsis. Three independent Arabidopsis HAP subunit 2 (AtHAP2) cDNAs were cloned by functional complementation of a yeast hap2 mutant, and two independent forms each of AtHAP3 and AtHAP5 cDNAs were detected in the expressed sequence tag database. Additional homologs (two of AtHAP3 and one of AtHAP5) have been identified from available Arabidopsis genomic sequences. Northern-blot analysis indicated ubiquitous expression for each AtHAP2 and AtHAP5 cDNA in a range of tissues, whereas expression of each AtHAP3 cDNA was under developmental and/or environmental regulation. The unexpected presence of multiple forms of each HAP homolog in Arabidopsis, compared with the single genes in yeast and vertebrates, suggests that the HAP2,3,5 complex may play diverse roles in gene transcription in higher plants.
Characterization of a Maize Tonoplast Aquaporin Expressed in Zones of Cell Division and Elongation1
Authors: Chaumont François , Barrieu François , Herman Eliot M. , Chrispeels Maarten J.
Published: July 2002

We studied aquaporins in maize (Zea mays), an important crop in which numerous studies on plant water relations have been carried out. A maize cDNA,ZmTIP1, was isolated by reverse transcription-coupled PCR using conserved motifs from plant aquaporins. The derived amino acid sequence of ZmTIP1 shows 76% sequence identity with the tonoplast aquaporin γ-TIP (tonoplast intrinsic protein) from Arabidopsis. Expression of ZmTIP1 in Xenopus laevisoocytes showed that it increased the osmotic water permeability of oocytes 5-fold; this water transport was inhibited by mercuric chloride. A cross-reacting antiserum made against bean α-TIP was used for immunocytochemical localization of ZmTIP1. These results indicate that this and/or other aquaporins is abundantly present in the small vacuoles of meristematic cells. Northern analysis demonstrated thatZmTIP1 is expressed in all plant organs. In situ hybridization showed a high ZmTIP1 expression in meristems and zones of cell enlargement: tips of primary and lateral roots, leaf primordia, and male and female inflorescence meristems. The high ZmTIP1 expression in meristems and expanding cells suggests that ZmTIP1 is needed (a) for vacuole biogenesis and (b) to support the rapid influx of water into vacuoles during cell expansion.
Auxin-Growth Relationships in Maize Coleoptiles and Pea Internodes and Control by Auxin of the Tissue Sensitivity to Auxin
Authors: Haga Ken , Iino Moritoshi
Published: July 2002

Growth of a zone of maize (Zea mays L.) coleoptiles and pea (Pisum sativum L.) internodes was greatly suppressed when the organ was decapitated or ringed at an upper position with the auxin transport inhibitorN-1-naphthylphthalamic acid (NPA) mixed with lanolin. The transport of apically applied 3H-labeled indole-3-acetic acid (IAA) was similarly inhibited by NPA. The growth suppressed by NPA or decapitation was restored by the IAA mixed with lanolin and applied directly to the zone, and the maximal capacity to respond to IAA did not change after NPA treatment, although it declined slightly after decapitation. The growth rate at IAA saturation was greater than the rate in intact, nontreated plants. It was concluded that growth is limited and controlled by auxin supplied from the apical region. In maize coleoptiles the sensitivity to IAA increased more than 3 times when the auxin level was reduced over a few hours with NPA treatment. This result, together with our previous result that the maximal capacity to respond to IAA declines in pea internodes when the IAA level is enhanced for a few hours, indicates that the IAA concentration-response relationship is subject to relatively slow adaptive regulation by IAA itself. The spontaneous growth recovery observed in decapitated maize coleoptiles was prevented by an NPA ring placed at an upper position of the stump, supporting the view that recovery is due to regenerated auxin-producing activity. The sensitivity increase also appeared to participate in an early recovery phase, causing a growth rate greater than in intact plants.
Protein Phosphorylation during Coconut Zygotic Embryo Development1
Authors: Islas-Flores Ignacio , Oropeza Carlos , Hernández-Sotomayor S.M. Teresa
Published: July 2002

Evidence was obtained on the occurrence of protein threonine, serine, and tyrosine (Tyr) kinases in developing coconut (Cocos nucifera L.) zygotic embryos, based on in vitro phosphorylation of proteins in the presence of [γ-32P]ATP, alkaline treatment, and thin-layer chromatography analysis, which showed the presence of [32P]phosphoserine, [32P]phosphothreonine, and [32P]phosphotyrosine in [32P]-labeled protein hydrolyzates. Tyr kinase activity was further confirmed in extracts of embryos at different stages of development using antiphosphotyrosine monoclonal antibodies and the synthetic peptide derived from the amino acid sequence surrounding the phosphorylation site in pp60src (RR-SRC), which is specific for Tyr kinases. Anti-phosphotyrosine western blotting revealed a changing profile of Tyr-phosphorylated proteins during embryo development. Tyr kinase activity, as assayed using RR-SRC, also changed during embryo development, showing two peaks of activity, one during early and another during late embryo development. In addition, the use of genistein, a Tyr kinase inhibitor, diminished the ability of extracts to phosphorylate RR-SRC. Results presented here show the occurrence of threonine, serine, and Tyr kinases in developing coconut zygotic embryos, and suggest that protein phosphorylation, and the possible inference of Tyr phosphorylation in particular, may play a role in the coordination of the development of embryos in this species.
Distinct Biochemical and Topological Properties of the 31- and 27-Kilodalton Plasma Membrane Intrinsic Protein Subgroups from Red Beet1
Authors: Barone Lucille M. , He Mu Helen , Shih Connie J. , Kashlan Kenan B. , Wasserman Bruce P.
Published: July 2002

Plasma membrane vesicles from red beet (Beta vulgaris L.) storage tissue contain two prominent major intrinsic protein species of 31 and 27 kD (X. Qi, C.Y Tai, B.P. Wasserman [1995] Plant Physiol 108: 387–392). In this study affinity-purified antibodies were used to investigate their localization and biochemical properties. Both plasma membrane intrinsic protein (PMIP) subgroups partitioned identically in sucrose gradients; however, each exhibited distinct properties when probed for multimer formation, and by limited proteolysis. The tendency of each PMIP species to form disulfide-linked aggregates was studied by inclusion of various sulfhydryl agents during tissue homogenization and vesicle isolation. In the absence of dithiothreitol and sulfhydryl reagents, PMIP27 yielded a mixture of monomeric and aggregated species. In contrast, generation of a monomeric species of PMIP31 required the addition of dithiothreitol, iodoacetic acid, orN-ethylmaleimide. Mixed disulfide-linked heterodimers between the PMIP31 and PMIP27 subgroups were not detected. Based on vectorial proteolysis of right-side-out vesicles with trypsin and hydropathy analysis of the predicted amino acid sequence derived from the gene encoding PMIP27, a topological model for a PMIP27 was established. Two exposed tryptic cleavage sites were identified from proteolysis of PMIP27, and each was distinct from the single exposed site previously identified in surface loop C of a PMIP31. Although the PMIP31 and PMIP27 species both contain integral proteins that appear to occur within a single vesicle population, these results demonstrate that each PMIP subgroup responds differently to perturbations of the membrane.
Characterization of a Low-Molecular-Weight Glutenin Subunit Gene from Bread Wheat and the Corresponding Protein That Represents a Major Subunit of the Glutenin Polymer
Authors: Masci Stefania , D'Ovidio Renato , Lafiandra Domenico , Kasarda Donald D.
Published: July 2002

Both high- and low-molecular-weight glutenin subunits (LMW-GS) play the major role in determining the viscoelastic properties of wheat (Triticum aestivum L.) flour. To date there has been no clear correspondence between the amino acid sequences of LMW-GS derived from DNA sequencing and those of actual LMW-GS present in the endosperm. We have characterized a particular LMW-GS from hexaploid bread wheat, a major component of the glutenin polymer, which we call the 42K LMW-GS, and have isolated and sequenced the putative corresponding gene. Extensive amino acid sequences obtained directly for this 42K LMW-GS indicate correspondence between this protein and the putative corresponding gene. This subunit did not show a cysteine (Cys) at position 5, in contrast to what has frequently been reported for nucleotide-based sequences of LMW-GS. This Cys has been replaced by one occurring in the repeated-sequence domain, leaving the total number of Cys residues in the molecule the same as in various other LMW-GS. On the basis of the deduced amino acid sequence and literature-based assignment of disulfide linkages, a computer-generated molecular model of the 42K subunit was constructed.
Abscisic Acid-Dependent and -Independent Expression of the Carrot Late-Embryogenesis-Abundant-Class Gene Dc3 in Transgenic Tobacco Seedlings
Authors: Siddiqui Najeeb U. , Chung Hwa-Jee , Thomas Terry L. , Drew Malcolm C.
Published: July 2002

We studied the expression of three promoter 5′ deletion constructs (−218, −599, and −1312) of the LEA (lateembryogenesis abundant)-class geneDc3 fused to β-glucuronidase (GUS), where each construct value refers to the number of base pairs upstream of the transcription start site at which the deletion occurred. TheDc3 gene is noted for its induction by abscisic acid (ABA), but its response to other plant hormones and various environmental stresses has not been reported previously for vegetative cells. Fourteen-day-old transgenic tobacco (Nicotiana tabacum L.) seedlings were exposed to dehydration, hypoxia, salinity, exogenous ethylene, or exogenous methyl jasmonate (MeJa). GUS activity was quantified fluorimetrically and expression was observed by histochemical staining of the seedlings. An increase in GUS activity was observed in plants with constructs −599 and −1312 in response to dehydration and salinity within 6 h of stress, and at 12 h in response to hypoxia. No increase in endogenous ABA was found in any of the three lines, even after 72 h of hypoxia. An ABA-independent increase in GUS activity was observed when endogenous ABA biosynthesis was blocked by fluridone and plants were exposed to 5 μL L−1 ethylene in air or 100 μm MeJa. Virtually no expression was observed in construct −218 in response to dehydration, salinity, or MeJa, but there was a moderate response to ethylene and hypoxia. This suggests that the region between −218 and −599 is necessary for ABA (dehydration and salinity)- and MeJa-dependent expression, whereas ethylene-mediated expression does not require this region of the promoter.
Evidence for Light-Stimulated Fatty Acid Synthesis in Soybean Fruit1
Authors: Willms Jennifer R. , Salon Christophe , Layzell David B.
Published: July 2002

In leaves, the light reactions of photosynthesis support fatty acid synthesis but disagreement exists as to whether this occurs in green oilseeds. To address this question, simultaneous measurements of the rates of CO2 and O2 exchange (CER and OER, respectively) were made in soybean (Glycine max L.) fruits. The imbalance between CER and OER was used to estimate the diverted reductant utilization rate (DRUR) in the equation: DRUR = 4 × (OER + CER). This yielded a quantitative measure of the rate of synthesis of biomass that is more reduced per unit carbon than glucose (in photosynthesizing tissues) or than the substrates of metabolism (in respiring tissues). The DRUR increased by about 2.2-fold when fruits were illuminated due to a greater increase in OER than decrease in CER. This characteristic was shown to be a property of the seed (not the pod wall), to be present in fruits at all developmental stages, and to reach a maximal response at relatively low light. When seeds were provided with 13CO2, light reduced12CO2 production but had little effect on13CO2 fixation. When they were provided with18O2, light stimulated16O2 production but had no effect on18O2 uptake. Together, these findings indicate that light stimulates fatty acid synthesis in photosynthetic oilseeds, probably by providing both ATP and carbon skeletons.
Overexpression of a Gene That Encodes the First Enzyme in the Biosynthesis of Asparagine-Linked Glycans Makes Plants Resistant to Tunicamycin and Obviates the Tunicamycin-Induced Unfolded Protein Response
Authors: Koizumi Nozomu , Ujino Tokuko , Sano Hiroshi , Chrispeels Maarten J.
Published: July 2002

The cytotoxic drug tunicamycin kills cells because it is a specific inhibitor of UDP-N-acetylglucosamine:dolichol phosphateN-acetylglucosamine-1-P transferase (GPT), an enzyme that catalyzes the initial step of the biosynthesis of dolichol-linked oligosaccharides. In the presence of tunicamycin, asparagine-linked glycoproteins made in the endoplasmic reticulum are not glycosylated with N-linked glycans, and therefore may not fold correctly. Such proteins may be targeted for breakdown. Cells that are treated with tunicamycin normally experience an unfolded protein response and induce genes that encode endoplasmic reticulum chaperones such as the binding protein (BiP). We isolated a cDNA clone for Arabidopsis GPT and overexpressed it in Arabidopsis. The transgenic plants have a 10-fold higher level of GPT activity and are resistant to 1 μg/mL tunicamycin, a concentration that kills control plants. Transgenic plants grown in the presence of tunicamycin haveN-glycosylated proteins and the drug does not induce BiP mRNA levels as it does in control plants. BiP mRNA levels are highly induced in both control and GPT-expressing plants by azetidine-2-carboxylate. These observations suggest that excess GPT activity obviates the normal unfolded protein response that cells experience when exposed to tunicamycin.
Direct Measurement of Xylem Pressure in Leaves of Intact Maize Plants. A Test of the Cohesion-Tension Theory Taking Hydraulic Architecture into Consideration
Authors: Wei Chunfang , Tyree Melvin T. , Steudle Ernst
Published: July 2002

The water relations of maize (Zea mays L. cv Helix) were documented in terms of hydraulic architecture and xylem pressure. A high-pressure flowmeter was used to characterize the hydraulic resistances of the root, stalk, and leaves. Xylem pressure measurements were made with a Scholander-Hammel pressure bomb and with a cell pressure probe. Evaporation rates were measured by gas exchange and by gravimetric measurements. Xylem pressure was altered by changing the light intensity, by controlling irrigation, or by gas pressure applied to the soil mass (using a root pressure bomb). Xylem pressure measured by the cell pressure probe and by the pressure bomb agreed over the entire measured range of 0 to −0.7 MPa. Experiments were consistent with the cohesion-tension theory. Xylem pressure changed rapidly and reversibly with changes in light intensity and root-bomb pressure. Increasing the root-bomb pressure increased the evaporation rate slightly when xylem pressure was negative and increased water flow rate through the shoots dramatically when xylem pressure was positive and guttation was observed. The hydraulic architecture model could predict all observed changes in water flow rate and xylem. We measured the cavitation threshold for oil- and water-filled pressure probes and provide some suggestions for improvement.