bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural MRI correlates of recognition memory in Alzheimer's
disease
Authors: Cahn Deborah A. , Sullivan Edith V. , Shear Paula K. , Marsh Laura , Fama Rosemary , Lim Kelvin O. , Yesavage Jerome A. , Tinklenberg Jared R. , Pfefferbaum and Adolf
Published: July 2002

Neuroimaging and lesion studies have demonstrated
that hippocampal volume correlates with memory performance,
but material-specific lateralization of this structure-function
relationship has been inconsistent. This MRI study examined
the relative contributions of left and right temporal lobe
volumes to verbal and nonverbal recognition memory in a
group of 20 Alzheimer's disease (AD) patients. There
was a significant relationship between extent of right
hippocampal and right temporal gray matter tissue volume
deficit and performance on the face recognition subtest
of the Warrington Recognition Memory Test. The face recognition
test correlated with right hemisphere volume but not to
left, indicating a material-specific relationship between
brain structure and function in this patient group. Right
temporal horn volume did not account for a significant
proportion of variance in face recognition memory. Although
word recognition was not significantly correlated with
either left or right hippocampal volume in the total group,
there was a strong correlation between left hippocampal
volume and word recognition memory in the female AD patients.
Thus, face recognition shows a material specific relationship
with select lateralized hippocampal and temporal cortical
volumes in AD patients, regardless of gender, whereas the
verbal recognition–left-hippocampal volume relationship
may be mediated by gender. (JINS, 1998, 4,
106–114.)
Performance discrepancies on the California Verbal Learning
Test–Children's Version in the standardization sample
Authors: DONDERS JACQUES
Published: July 2002

The standardization data for the California Verbal
Learning Test–Children's Version (CVLT–C)
were used to evaluate statistically significant discrepancies
between key quantitative variables of this instrument,
as well as the base rate of specific discrepancies. The
results indicated that apparently large discrepancies between
the respective standard scores were actually fairly common.
However, for 3 of the 4 contrasts, discrepancies that equaled
or exceeded 1.5 z-score points in the hypothesized
direction were sufficiently unusual to be considered clinically
significant. For a 4th contrast, discrepancies that equaled
or exceeded 1 z-score point in the hypothesized
direction appeared to meet this criterion. It is suggested
that the interpretation of clinically obtained CVLT–C
profiles should focus primarily on specific quantitative
variables, with inclusion of consideration of the presented
base rates of discrepancies between the respective z
scores. (JINS, 1999, 5, 26–31.)
Emotion processing in the visual and auditory domains by
patients with Alzheimer's disease
Authors: KOFF ELISSA , ZAITCHIK DEBORAH , MONTEPARE JOANN , ALBERT MARILYN S.
Published: July 2002

The ability to process emotional information was
assessed in 42 individuals: 23 patients with Alzheimer's
disease (AD) and 19 healthy elderly controls. Four tasks
assessed the ability to recognize emotion in audiotaped
voices, in drawings of emotional situations, and in videotaped
vignettes displaying emotions in facial expression, gestures,
and body movements. Hemispheric dominance for processing
facial expressions of emotions was also examined. There
were no consistent group differences in the ability to
process emotion presented via the auditory domain
(i.e., nonverbal sounds, such as crying or shrieking, and
speech prosody). Controls were, however, significantly
better than the AD patients in identifying emotions depicted
in drawings of emotional situations and in videotaped scenes
displaying faces, gestures, and body movements. These differences
were maintained after statistically adjusting for the visuospatial
abilities of the participants. After a statistical adjustment
for abstraction ability, some of the tasks continued to
differentiate the groups (e.g., the emotional drawings
task, the videotaped displays of faces), but others did
not. These results confirm and extend previous results
indicating that AD patients do not have a primary deficit
in the processing of emotion. They suggest that the difficulties
of the AD patients in perceiving emotion are secondary
to the cognitive impairments associated with AD. (JINS,
1999, 5, 32–40.)
Global macroeconomic sustainability: a dynamic general equilibrium approach
Authors: BAILEY RALPH W. , CLARKE ROSEMARY
Published: July 2002

Previous empirical studies assessing sustainability have adopted the weak sustainability indicator (WSI) which measures changes in the stock of physical and natural capital. Whereas these studies have been retrospective, we use a dynamic general equilibrium model to investigate global and regional sustainability over the period 1985–2050, focusing on fossil fuel extraction. Our standard scenario predicts increasing WSI values suggesting global sustainability in all periods to 2050 as, despite a rising world oil price, the introduction of backstop fuels in 2010 provides an alternative source of energy. A more pessimistic scenario examines possible outcomes in the absence of energy saving technological change and backstops fuels. WSI values still indicate global sustainability, though economic growth is only half that predicted by the more optimistic model, and two countries—USA and Brazil—are unsustainable.
The SndObj Sound Object Library
Authors: LAZZARINI VICTOR E. P.
Published: July 2002

The SndObj Sound Object Library is a C++ object-oriented audio processing
framework and toolkit. This article initially examines some of the currently
available sound processing packages, including sound compilers, programming
libraries and toolkits. It reviews the processes involved in the use of
these systems and their strengths and weaknesses. Some application examples
are also provided. In this context, the SndObj library is presented and its
components are discussed in detail. The article shows the library as
composed of a set of classes that encapsulate all processes involved in
synthesis, processing and IO operations. Programming examples are included
to show some uses of the system. These, together with library binaries,
source code and complete documentation, are included in the downloadable
package, available on the Internet. Possible future developments and
applications are considered. The library is demonstrated to provide a
useful base for research and development of audio processing software.
Differences in the metrical behavior of Old English finite verbs: evidence for grammaticalization
Authors: GETTY MICHAEL
Published: July 2002

This paper deals with the metrical behavior of a class of verbs in Old English whose descendants became the syntactically distinct auxiliaries of the modern period (have, be, may, will, shall, and associated forms). Contrasting two poems from the Old English period (Beowulf and The Battle of Maldon), I show that while the verbs in question show consistently stressed metrical placement in Beowulf, in Maldon they show a pronounced tendency to be placed in unstressed metrical positions, while verbs outside the eventual class of auxiliaries differ indiscriminately. In this way, the poetry suggests a phonological difference between pre-auxiliaries and other verbs perhaps centuries before corresponding morphological and syntactic differences fully emerged in the Middle and early Modern English periods.
The grammar, meaning, and referential functions of else
Authors: Yap Foong Ha , Celce-Murcia Marianne
Published: July 2002

Although else is recognized as a cohesive device (e.g. Halliday & Hasan, 1976: 76), it has received relatively little attention in the literature. To help remedy the situation, this article investigates how native speakers use else in both written and spoken discourse. We first review the literature for a description of the meaning(s) of else, then identify its most common meaning as reflected in its frequency of use in American English native-speaker discourse. More specifically, we undertake a quantitative analysis of the frequency and distribution of different types of else constructions, as well as a qualitative analysis of how else functions as a referential and cohesive marker. The unique referential role of else is then highlighted by contrasting it with its closest synonym, namely other. It is shown that these two referential and cohesive markers complement each other, with else playing a less specified semantic role than other.
The position of adjectives on the noun–verb continuum
Authors: Berg Thomas
Published: July 2002

Previous work in syntax, semantics, pragmatics, and psycholinguistics has shown adjectives to take an intermediate position between nouns and verbs. This claim is made more specific in this article through a phonological (and to a lesser extent, morphological) test of the ‘equidistance hypothesis’. On seven criteria, English adjectives are found to exhibit a much greater affinity with nouns than with verbs. This pattern of results is brought about by the syntagmatic context in which the three word classes typically occur. The rhythmic context in which adjectives are embedded is similar to that of nouns but dissimilar to that of verbs. This bias gives rise to suprasegmental differences which in turn lead to segmental differences. The proposed account rests upon the assumption, independently verified, that nouns and verbs differ in length, a disparity that might have a syntactic cause. A tentative case is made for a cross-level harmony constraint according to which the similarity between adjectives and nouns is not particular to the phonological level but characterizes the linguistic system more generally.
ARE TECHNOLOGY SHOCKS NONLINEAR?
Authors: Altuğ Sumru , Ashley Richard A. , Patterson Douglas M.
Published: July 2002

The behavior of postwar real U.S. GNP, the inputs to an
aggregate production function, and several formulations of the associated Solow
residuals for the presence of nonlinearities in their generating mechanisms are examined.
Three different statistical tests for nonlinearity are implemented: the
McLeod-Li test, the BDS test, and the Hinich bicovariance test.
We find substantial evidence for nonlinearity in the generating mechanism of
real GNP growth but no evidence for nonlinearity in the Solow residuals.
We further find that the generating mechanism of the labor input series is
nonlinear, whereas that of the capital services input appears to be linear.
We therefore conclude that the observed nonlinearity in real output arises
from nonlinearities in the labor markets, not from nonlinearities in the
technical shocks driving the system. Finally, we investigate the source of
the nonlinearities in the labor markets by examining simulated data from a
model of the Dutch economy with asymmetric adjustment costs.
Long-run trends in world trade and income
Authors: IRWIN DOUGLAS A.
Published: July 2002

This paper examines the statistical relationship between world trade and
world income (GDP) over three different epochs: the pre-World War I era
(1870–1913), the interwar era (1920–1938), and the post-World War II era
(1950–2000). The results indicate that trade grew slightly more rapidly than income
in the late nineteenth century, with little structural change in the trade–income
relationship. In the interwar and post-war periods, the trade–income relationship
can be divided into different periods due to structural breaks, but since the mid
1980s trade has been more responsive to income than in any other period under
consideration. The trade policy regime differed in each period, from the bilateral
treaty network in the late nineteenth century to interwar protectionism to post-war
GATT/WTO liberalization. The commodity composition of trade has also shifted
from primary commodities to manufactured goods over the past century, but the
results cannot directly determine the reasons for the increased sensitivity of trade to
income.
Key events of pancreas formation are triggered in gut endoderm by ectopic expression of pancreatic regulatory genes
Authors: Grapin-Botton Anne , Majithia Amit R. , Melton Douglas A.
Published: July 2002

The mechanisms by which the epithelium of the digestive tract and its associated glands are specified are largely unknown. One clue is that several transcription factors are expressed in specific regions of the endoderm prior to and during organogenesis. Pdx-1, for example, is expressed in the duodenum and pancreas and Pdx-1inactivation results in an arrest of pancreatic development after buds formation. Similarly, ngn3 is transiently expressed in the developing pancreas and a knockout results in the absence of endocrine cells. This paper focuses on the question of whether these and other transcription factors, known to be necessary for pancreatic development, are also sufficient to drive a program of pancreatic organogenesis. Using in ovo electroporation of chick embryos, we show that ectopic expression of Pdx-1 or ngn3 causes cells to bud out of the epithelium like pancreatic progenitors. The Pdx-1-expressing cells extinguish markers for other nonpancreatic regions of the endoderm and initiate, but do not complete, pancreatic cytodifferentiation. Ectopic expression of ngn3 is sufficient to turn endodermal cells of any region into endocrine cells that form islets expressing glucagon and somatostatin in the mesenchyme. The results suggest that simple gene combinations could be used in stem cells to achieve specific endodermal tissue differentiation.
The transcription factor FoxH1 (FAST) mediates Nodal signaling during anterior-posterior patterning and node formation in the mouse
Authors: Yamamoto Masamichi , Meno Chikara , Sakai Yasuo , Shiratori Hidetaka , Mochida Kyoko , Ikawa Yayoi , Saijoh Yukio , Hamada Hiroshi
Published: July 2002

FoxH1 (FAST) is a transcription factor that mediates signaling by transforming growth factor–β, Activin, and Nodal. The role of FoxH1 in development has now been investigated by the generation and analysis of FoxH1-deficient (FoxH1−/−) mice. TheFoxH1−/− embryos showed various patterning defects that recapitulate most of the defects induced by the loss of Nodal signaling. A substantial proportion ofFoxH1−/− embryos failed to orient the anterior-posterior (A-P) axis correctly, as do mice lacking Cripto, a coreceptor for Nodal. In less severely affectedFoxH1−/− embryos, A-P polarity was established, but the primitive streak failed to elongate, resulting in the lack of a definitive node and its derivatives. Heterozygosity fornodal renders the FoxH1−/−phenotype more severe, indicative of a genetic interaction betweenFoxH1 and nodal. The expression ofFoxH1 in the primitive endoderm rescued the A-P patterning defects, but not the midline defects, ofFoxH1−/− mice. These results indicate that a Nodal-FoxH1 signaling pathway plays a central role in A-P patterning and node formation in the mouse.
Molecular and Biochemical Characterization of a Cold-Regulated PhosphoethanolamineN-Methyltransferase from Wheat
Authors: Charron Jean-Benoit Frenette , Breton Ghislain , Danyluk Jean , Muzac Ingrid , Ibrahim Ragai K. , Sarhan Fathey
Published: July 2002

A cDNA that encodes a methyltransferase (MT) was cloned from a cold-acclimated wheat (Triticum aestivum) cDNA library. Molecular analysis indicated that the enzyme WPEAMT (wheat phosphoethanolamine [P-EA] MT) is a bipartite protein with two separate sets ofS-adenosyl-l-Met-binding domains, one close to the N-terminal end and the second close to the C-terminal end. The recombinant protein was found to catalyze the three sequential methylations of P-EA to form phosphocholine, a key precursor for the synthesis of phosphatidylcholine and glycine betaine in plants. Deletion and mutation analyses of the twoS-adenosyl-l-Met-binding domains indicated that the N-terminal domain could perform the threeN-methylation steps transforming P-EA to phosphocholine. This is in contrast to the MT from spinach (Spinacia oleracea), suggesting a different functional evolution for the monocot enzyme. The truncated C-terminal and the N-terminal mutated enzyme were only able to methylate phosphomonomethylethanolamine and phosphodimethylethanolamine, but not P-EA. This may suggest that the C-terminal part is involved in regulating the rate and the equilibrium of the three methylation steps. Northern and western analyses demonstrated that both Wpeamt transcript and the corresponding protein are up-regulated during cold acclimation. This accumulation was associated with an increase in enzyme activity, suggesting that the higher activity is due to de novo protein synthesis. The role of this enzyme during cold acclimation and the development of freezing tolerance are discussed.
Transgenic AEQUORIN Reveals Organ-Specific Cytosolic Ca2+ Responses to Anoxia in Arabidopsis thaliana Seedlings
Authors: Sedbrook J. C. , Kronebusch P. J. , Borisy G. G. , Trewavas A. J. , Masson P. H.
Published: July 2002

Using the transgenic AEQUORIN system, we showed that the cotyledons and leaves of Arabidopsis thaliana seedlings developed a biphasic luminescence response to anoxia, indicating changes in cytosolic Ca2+ levels. A fast and transient luminescence peak occurred within minutes of anoxia, followed by a second, prolonged luminescence response that lasted 1.5 to 4 h. The Ca2+ channel blockers Gd3+, La3+, and ruthenium red (RR) partially inhibited the first response and promoted a larger and earlier second response, suggesting different origins for these responses. Both Gd3+ and RR also partially inhibited anaerobic induction of alcohol dehydrogenase gene expression. However, although anaerobic alcohol dehydrogenase gene induction occurred in seedlings exposed to water-agar medium and in roots, related luminescence responses were absent. Upon return to normoxia, the luminescence of cotyledons, leaves, and roots dropped quickly, before increasing again in a Gd3+-, La3+-, ethyleneglycol-bis(β-aminoethyl ether)-N,N′-tetraacetic acid-, and RR-sensitive fashion.
Purification and Characterization of the Reconstitutively Active Adenine Nucleotide Carrier from Maize Mitochondria
Authors: Genchi G. , Ponzone C. , Bisaccia F. , De Santis A. , Stefanizzi L. , Palmieri F.
Published: July 2002

The adenine nucleotide carrier from maize (Zea mays L. cv B 73) shoot mitochondria was solubilized with Triton X-100 and purified by sequential chromatography on hydroxyapatite and Matrex Gel Blue B in the presence of cardiolipin and asolectin. Sodium dodecyl sulfate-gel electrophoresis of the purified fraction showed a single polypeptide band with an apparent molecular mass of 32 kD. When reconstituted in liposomes, the adenine nucleotide carrier catalyzed a pyridoxal 5[prime]-phosphate-sensitive ATP/ATP exchange. It was purified 168-fold with a recovery of 60% and a protein yield of 0.25% with respect to the mitochondrial extract. Among the various substrates and inhibitors tested, the reconstituted protein transported only ADP, ATP, GDP, and GTP, and was inhibited by atractyloside, bongkrekate, phenylisothiocianate, pyridoxal 5[prime]-phosphate, and mersalyl (but not N-ethylmaleimide). Maximum initial velocity of the reconstituted ATP/ATP exchange was determined to be 2.2 [mu]mol min-1 mg-1 protein at 25[deg]C. The half-saturation constants and the corresponding inhibition constants were 17 [mu]M for ATP, 26 [mu]M for ADP, 59 [mu]M for GTP, and 125 [mu]M for GDP. The activation energy of the ATP/ATP exchange was 48 kilojoule/mol between 0 and 15[deg]C, and 22 kilojoule/mol between 15 and 35[deg]C. Partial amino acid sequences showed that the purified protein was the product of the ANT-G1 gene sequenced previously (B. Bathgate, A. Baker, C.J. Leaver [1989] Eur J Biochem 183: 303–310).
Identification of a Chloroplast Coenzyme A-Binding Protein Related to the Peroxisomal Thiolases
Authors: Yang L. M. , Lamppa G.
Published: July 2002

A 30-kD coenzyme A (CoA)-binding protein was isolated from spinach (Spinacea oleracea) chloroplast soluble extracts using affinity chromatography under conditions in which 95% of the total protein was excluded. The 30-kD protein contains an eight-amino-acid sequence, DVRLYYGA, that is identical to a region in a 36-kD protein of unknown function that is encoded by a kiwifruit (Actinidia deliciosa) cDNA. Southern blotting also detected a spinach gene that is related to the kiwifruit cDNA. The kiwifruit 36-kD protein that was synthesized in Escherichia coli was imported into chloroplasts and cleaved to a 30-kD form; it was processed to the same size in an organelle-free assay. Furthermore, the kiwifruit protein specifically bound to CoA. The kiwifruit protein contains a single cysteine within a domain that is related to the peroxisomal β-ketoacyl-CoA thiolases, which catalyze the CoA-dependent degradative step of fatty acid β-oxidation. Within 50 amino acids surrounding the cysteine, considered to be part of the thiolase active site, the kiwifruit protein shows approximately 26% sequence identity with the mango, cucumber, and rat peroxisomal thiolases. N-terminal alignment with these enzymes, relative to the cysteine, indicates that the 36-kD protein is cleaved after serine-58 during import, agreeing with the estimated size (approximately 6 kD) of a transit peptide. The 30-kD protein is also related to the E. coli and mitochondrial thiolases, as well as to the acetoacetyl-CoA thiolases of prokaryotes. Features distinguish it from members of the thiolase family, suggesting that it carries out a related but novel function. The protein is more distantly related to chloroplast β-ketoacyl-acyl carrier protein synthase III, the initial condensing enzyme of fatty acid synthetase that utilizes acetyl-CoA.
Identification and Partial Characterization of the Pectin Methyltransferase “Homogalacturonan-Methyltransferase” from Membranes of Tobacco Cell Suspensions1
Authors: Goubet Florence , Council Leona N. , Mohnen Debra
Published: July 2002

A membrane preparation from tobacco (Nicotiana tabacum L.) cells contains at least one enzyme that is capable of transferring the methyl group fromS-adenosyl-methionine (SAM) to the C6 carboxyl of homogalacturonan present in the membranes. This enzyme is named homogalacturonan-methyltransferase (HGA-MT) to distinguish it from methyltransferases that catalyze methyletherification of the pectic polysaccharides rhamnogalacturonan I or rhamnogalacturonan II. A trichloroacetic acid precipitation assay was used to measure HGA-MT activity, because published procedures to recover pectic polysaccharides via ethanol or chloroform:methanol precipitation lead to high and variable background radioactivity in the product pellet. Attempts to reduce the incorporation of the 14C-methyl group from SAM into pectin by the addition of the alternative methyl donor 5-methyltetrahydrofolate were unsuccessful, supporting the role of SAM as the authentic methyl donor for HGA-MT. The pH optimum for HGA-MT in membranes was 7.8, the apparent Michaelis constant for SAM was 38 μm, and the maximum initial velocity was 0.81 pkat mg−1 protein. At least 59% of the radiolabeled product was judged to be methylesterified homogalacturonan, based on the release of radioactivity from the product after a mild base treatment and via enzymatic hydrolysis by a purified pectin methylesterase. The released radioactivity eluted with a retention time identical to that of methanol upon fractionation over an organic acid column. Cleavage of the radiolabeled product by endopolygalacturonase into fragments that migrated as small oligomers of HGA during thin-layer chromatography, and the fact that HGA-MT activity in the membranes is stimulated by uridine 5′-diphosphate galacturonic acid, a substrate for HGA synthesis, confirms that the bulk of the product recovered from tobacco membranes incubated with SAM is methylesterified HGA.
Induction and Regulation of Expression of a Low-CO2-Induced Mitochondrial Carbonic Anhydrase inChlamydomonas reinhardtii
Authors: Eriksson Mats , Villand Per , Gardeström Per , Samuelsson Göran
Published: July 2002

The time course of and the influence of light intensity and light quality on the induction of a mitochondrial carbonic anhydrase (CA) in the unicellular green algaChlamydomonas reinhardtii was characterized using western and northern blots. This CA was expressed only under low-CO2 conditions (ambient air). In asynchronously grown cells, the mRNA was detected 15 min after transfer from air containing 5% CO2 to ambient air, and the 21-kD polypeptide was detected on western blots after 1 h. When transferred back to air containing 5% CO2, the mRNA disappeared within 1 h and the polypeptide was degraded within 3 d. Photosynthesis was required for the induction in asynchronous cultures. The induction increased with light up to 500 μmol m−2s−1, where saturation occurred. In cells grown synchronously, however, expression of the mitochondrial CA was also detected in darkness. Under such conditions the expression followed a circadian rhythm, with mRNA appearing in the dark 30 min before the light was turned on. Algae left in darkness continued this rhythm for several days.
Photosystem II Cyclic Heterogeneity and Photoactivation in the Diazotrophic, Unicellular CyanobacteriumCyanotheceSpecies ATCC 511421
Authors: Meunier Pascal C. , Colón-López Milagros S. , Sherman Louis A.
Published: July 2002

The unicellular, diazotrophic cyanobacterium Cyanothece sp. ATCC 51142 demonstrated important modifications to photosystem II (PSII) centers when grown under light/dark N2-fixing conditions. The properties of PSII were studied throughout the diurnal cycle using O2-flash-yield and pulse-amplitude-modulated fluorescence techniques. Nonphotochemical quenching (qN) of PSII increased during N2 fixation and persisted after treatments known to induce transitions to state 1. TheqN was high in cells grown in the dark, and then disappeared progressively during the first 4 h of light growth. The photoactivation probability, ε, demonstrated interesting oscillations, with peaks near 3 h of darkness and 4 and 10 h of light. Experiments and calculations of the S-state distribution indicated that PSII displays a high level of heterogeneity, especially as the cells prepare for N2 fixation. We conclude that the oxidizing side of PSII is strongly affected during the period before and after the peak of nitrogenase activity; changes include a lowered capacity for O2 evolution, altered dark stability of PSII centers, and substantial changes in qN.
Polygalacturonase-Mediated Solubilization and Depolymerization of Pectic Polymers in Tomato Fruit Cell Walls1
Authors: Chun Jong-Pil , Huber Donald J.
Published: July 2002

The hydrolysis of cell wall pectins by tomato (Lycopersicon esculentum) polygalacturonase (PG) in vitro is more extensive than the degradation affecting these polymers during ripening. We examined the hydrolysis of polygalacturonic acid and cell walls by PG isozyme 2 (PG2) under conditions widely adopted in the literature (pH 4.5 and containing Na+) and under conditions approximating the apoplastic environment of tomato fruit (pH 6.0 and K+ as the predominate cation). The pH optima for PG2 in the presence of K+ were 1.5 and 0.5 units higher for the hydrolysis of polygalacturonic acid and cell walls, respectively, compared with activity in the presence of Na+. Increasing K+concentration stimulated pectin solubilization at pH 4.5 but had little influence at pH 6.0. Pectin depolymerization by PG2 was extensive at pH values from 4.0 to 5.0 and was further enhanced at high K+levels. Oligomers were abundant products in in vitro reactions at pH 4.0 to 5.0, decreased sharply at pH 5.5, and were negligible at pH 6.0. EDTA stimulated PG-mediated pectin solubilization at pH 6.0 but did not promote oligomer production. Ca2+ suppressed PG-mediated pectin release at pH 4.5 yet had minimal influence on the proportional recovery of oligomers. Extensive pectin breakdown in processed tomato might be explained in part by cation- and low-pH-induced stimulation of PG and other wall-associated enzymes.
Comparison of Binding Properties and Early Biological Effects of Elicitins in Tobacco Cells
Authors: Bourque Stéphane , Ponchet Michel , Binet Marie-Noëlle , Ricci Pierre , Pugin Alain , Lebrun-Garcia Angela
Published: July 2002

Elicitins are a family of small proteins secreted by Phytophthora species that have a high degree of homology and elicit defense reactions in tobacco (Nicotiana tabacum). They display acidic or basic characteristics, the acidic elicitins being less efficient in inducing plant necrosis. In this study we compared the binding properties of four elicitins (two basic and two acidic) and early-induced signal transduction events (Ca2+ influx, extracellular medium alkalinization, and active oxygen species production). The affinity for tobacco plasma membrane-binding sites and the number of binding sites were similar for all four elicitins. Furthermore, elicitins compete with one another for binding sites, suggesting that they interact with the same receptor. The four elicitins induced Ca2+ influx, extracellular medium alkalinization, and the production of active oxygen species in tobacco cell suspensions, but the intensity and kinetics of these effects were different from one elicitin to another. As a general observation the concentrations that induce similar levels of biological activities were lower for basic elicitins (with the exception of cinnamomin-induced Ca2+ uptake). The qualitative similarity of early events induced by elicitins indicates a common transduction scheme, whereas fine signal transduction tuning is different in each elicitin.
Overexpression of Arabidopsis Phytochrome B Inhibits Phytochrome A Function in the Presence of Sucrose1
Authors: Short Timothy W.
Published: July 2002

Overexpression of phytochrome B (phyB) in Arabidopsis has previously been demonstrated to result in dominant negative interference of phytochrome A (phyA)-mediated hypocotyl growth inhibition in far-red (FR) light. This phenomenon has been examined further in this study and has been found to be dependent on the FR fluence rate and on the availability of metabolizable sugars in the growth medium. Poorly metabolized sugars capable of activating the putative hexokinase sensory function were not effective in eliciting the phytochrome interference response. Overexpressed phyB lacking the chromophore-binding site was also effective at inhibiting the phyA response, especially at higher fluence rates of FR. Overexpressed phyB produces the dominant negative phenotype without any apparent effect on phyA abundance or degradation. It is possible that phyA and phyB interact with a common reaction partner but that either the energy state of the cell or a separate sugar-signaling mechanism modulates the phytochrome-signaling interactions.
Transgenic Overexpression of the Transcription FactorAlfin1Enhances Expression of the Endogenous MsPRP2Gene in Alfalfa and Improves Salinity Tolerance of the Plants1
Authors: Winicov Ilga , Bastola Dhundy R.
Published: July 2002

Alfin1cDNA encodes a putative transcription factor associated with NaCl tolerance in alfalfa (Medicago sativa L.). The recombinant protein binds DNA in a sequence-specific manner, including promoter fragments of the NaCl-inducible gene MsPRP2. Alfin1 function was tested in transgenic alfalfa under the control of the 35S promoter in the sense and antisense orientations with the endogenous MsPRP2 as a reporter gene. Calli overexpressing Alfin1 were more resistant to growth inhibition by 171 mm NaCl than vector-transformed controls, whereas calli expressing Alfin1 in the antisense orientation were more sensitive to NaCl inhibition. Transgenic plants overexpressing Alfin1 in the sense orientation grew well. In contrast, the antisense transgenic plants grew poorly in soil, demonstrating that Alfin1 expression is essential for normal plant development. Transgenic calli and plant roots overexpressing Alfin1 showed enhanced levels of endogenous MsPRP2 mRNA accumulation. However,MsPRP2 mRNA accumulation was also regulated in a tissue-specific manner, as shown in leaves of transgenic plants overexpressing Alfin1. These results suggest that Alfin1 acts as a transcriptional regulator in plants and regulatesMsPRP2 expression in alfalfa.Alfin1 overexpressing transgenic plants showed salinity tolerance comparable to one of our NaCl-tolerant plants, indicating that Alfin1 also functions in gene regulation in NaCl tolerance.
Periplasmic Carbonic Anhydrase Structural Gene (Cah1) Mutant in Chlamydomonas reinhardtii1
Authors: Van Kyujung , Spalding Martin H.
Published: July 2002

To survive in various conditions of CO2 availability, Chlamydomonas reinhardtiishows adaptive changes, such as induction of a CO2-concentrating mechanism, changes in cell organization, and induction of several genes, including a periplasmic carbonic anhydrase (pCA1) encoded by Cah1. Among a collection of insertionally generated mutants, a mutant has been isolated that showed no pCA1 protein and no Cah1 mRNA. This mutant strain, designated cah1-1, has been confirmed to have a disruption in the Cah1 gene caused by a singleArg7 insert. The most interesting feature ofcah1-1 is its lack of any significant growth phenotype. There is no major difference in growth or photosynthesis between the wild type andcah1-1 over a pH range from 5.0 to 9.0 even though this mutant apparently lacks Cah1 expression in air. Although the presence of pCA1 apparently gives some minor benefit at very low CO2 concentrations, the characteristics of this Cah1 null mutant demonstrate that pCA1 is not essential for function of the CO2-concentrating mechanism or for growth of C. reinhardtii at limiting CO2 concentrations.
Exposure to Low Irradiances Favors the Synthesis of 9-cis β,β-Carotene in Dunaliella salina (Teod.)
Authors: Orset Sandra Charlotte , Young Andrew John
Published: July 2002

We examined the effect of irradiance on the synthesis of β-carotene and its isomers by Dunaliella salina. Growth irradiance had a marked effect both on growth of the alga (which was suppressed at both low and high irradiances) and on the accumulation of β-carotene. The accumulation of β-carotene but not α-carotene was closely linked to an increase in irradiance. Growth at low irradiances (20–50 μmol m−2s−1) promoted a high ratio of 9-cis to all-trans β-carotene (>2:1), while exposure to high irradiances (200–1,250 μmol m−2 s−1) resulted in a large reduction in this ratio (to <0.45:1). A similar pattern was seen for the geometric isomers of α-carotene, with exposure to low irradiance favoring the accumulation of the 9-cis form. The carotenoid biosynthesis inhibitors 4-chloro-5(methylamino)-2-(α-α-α-trifluoro-m-tolyl)-3-(sH)-pyridazinone and 2-(4-chlorophenylthio)triethylamine caused the accumulation of the precursors phytoene and lycopene, respectively, in D. salina. High-performance liquid chromatography and infrared analysis showed that phytoene adopted the 15-cis and all-trans forms (as in higher plants), and that lycopene primarily adopted the all-trans form. This indicates that isomerization of β-carotene takes place during or after cyclization.
Accumulation ofENOD2-Like Transcripts in Non-Nodulating Woody Papilionoid Legumes
Authors: Foster Carol M. , Horner Harry T. , Graves William R.
Published: July 2002

Japanese pagodatree (Styphnolobium japonicum [L.] Schott) and American yellowwood (Cladrastis kentukeaDum.-Cours.) Rudd are the first woody, non-nodulating papilionoid legumes shown to possess putative early nodulin 2 (ENOD2) genes. ENOD2 cDNAs from Japanese pagodatree (807 bp) and American yellowwood (735 bp) have 75% to 79% sequence identity to ENOD2 sequences and encode deduced proteins that possess conserved ENOD2 pentapeptides (PPHEK and PPEYQ). Lower percentages of glucose and higher percentages of histidine and valine suggest that SjENOD2 andCkENOD2 are different from other ENOD2s. Hybridization analyses indicate the clones representENOD2 gene families of two to four genes in Japanese pagodatree and American yellowwood genomes, andENOD2-like transcripts were detected in stems and flowers, as well as roots. Only roots of control species that nodulate,Maackia amurensis Rupr. & Maxim. and alfalfa (Medicago sativa), produced pseudonodules after treatment with zeatin or 2,3,5-triiodobenzoic acid, an auxin transport inhibitor. Accumulation of MaENOD2 transcripts was enhanced during the first 10 d of treatment, but 2,3,5-triiodobenzoic acid and zeatin enhanced transcript accumulation after 30 d in roots of Japanese pagodatree and American yellowwood. Characteristics that distinguish ENOD2 gene families in basal, non-nodulating woody legumes from otherENOD2 genes may provide new information about the function of these genes during symbiotic and non-symbiotic organ development.
Negative Interference of Endogenous Phytochrome B with Phytochrome A Function in Arabidopsis
Authors: Hennig Lars , Poppe Christoph , Sweere Uta , Martin Annette , Schäfer Eberhard
Published: July 2002

To study negative interactions between phytochromes, phytochrome B (phyB) overexpressor lines, the mutants phyA-201,phyB-4, phyB-5, phyD-1,phyA-201 phyB-5, phyA-201 phyD-1, andphyB-5 phyD-1 of Arabidopsis were used. Endogenous phyB, but not phytochrome D (phyD), partly suppressed phytochrome A (phyA)-dependent inhibition of hypocotyl elongation in far-red light (FR). Dichromatic irradiation demonstrated that the negative effect of phyB was largely independent of the photoequilibrium, i.e. far-red light absorbing form of phytochrome formation. Moreover,phyB-4, a mutant impaired in signal transduction, did not show a loss of inhibition of phyA by phyB. Overexpression of phyB, conversely, resulted in an enhanced inhibition of phyA function, even in the absence of supplementary carbohydrates. However, overexpression of a mutated phyB, which cannot incorporate the chromophore, had no detectable effect on phyA action. In addition to seedling growth, accumulation of anthocyanins in FR, another manifestation of the high irradiance response, was strongly influenced by phyB holoprotein. Induction of seed germination by FR, a very low fluence response, was suppressed by both endogenous phyB and phyD. In conclusion, we show that both classical response modes of phyA, high irradiance response, and very low fluence response are subject to an inhibitory action of phyB-like phytochromes. Possible mechanisms of the negative interference are discussed.
Differential Regulation of a Family of Apyrase Genes fromMedicago truncatula
Authors: Cohn Jonathan R. , Uhm Taesik , Ramu Senthil , Nam Yong-Woo , Kim Dong-Jin , Penmetsa R. Varma , Wood Todd C. , Denny Roxanne L. , Young Nevin D. , Cook Douglas R. , Stacey Gary
Published: July 2002

Four putative apyrase genes were identified from the model legumeMedicago truncatula. Two of the genes identified fromM. truncatula (Mtapy1 and Mtapy4) are expressed in roots and are inducible within 3 h after inoculation with Sinorhizobium meliloti. The level of mRNA expression of the other two putative apyrases, Mtapy2and Mtapy3, was unaffected by rhizobial inoculation. Screening of a bacterial artificial chromosome library of M. truncatula genomic DNA showed that Mtapy1,Mtapy3, and Mtapy4 are present on a single bacterial artificial chromosome clone. This apyrase cluster was mapped to linkage group seven. A syntenic region on soybean linkage group J was found to contain at least two apyrase genes. Screening of nodulation deficient mutants of M. truncatula revealed that two such mutants do not express apyrases to any detectable level. The data suggest a role for apyrases early in the nodulation response before the involvement of root cortical cell division leading to the nodule structure.
shygrl1Is a Mutant Affected in Multiple Aspects of Photomorphogenesis
Authors: Santiago-Ong May , Green Rachel M. , Tingay Sonia , Brusslan Judy A. , Tobin Elaine M.
Published: July 2002

We have used a counter-selection strategy based on aberrant phytochrome regulation of an Lhcb gene to isolate an Arabidopsis mutant designated shygrl1(shg1). shg1 seedlings have reduced phytochrome-mediated induction of the Lhcb gene family, but normal phytochrome-mediated induction of several other genes, including the rbcS1a gene. Additional phenotypes observed in shg1 plants include reduced chlorophyll in leaves and additional photomorphogenic abnormalities when the seedlings are grown on medium containing sucrose. Mutations in the TATA-proximal region of the Lhcb1*3 promoter that are known to be important for phytochrome regulation affected reporter gene expression in a manner similar to the shg1 mutation. Our results are consistent with the possibility that the mutation either leads to defective chloroplast development or to aberrant phytochrome regulation. They also add to the evidence of complex interactions between light- and sucrose-regulated pathways.
Cytoplasmic pH Dynamics in Maize Pulvinal Cells Induced by Gravity Vector Changes,
Authors: Johannes Eva , Collings David A. , Rink Jochen C. , Allen Nina Strömgren
Published: July 2002

In maize (Zea mays) and other grasses, changes in orientation of stems are perceived by pulvinal tissue, which responds to the stimulus by differential growth resulting in upward bending of the stem. The amyloplast-containing bundle sheath cells are the sites of gravity perception, although the initial steps of gravity perception and transmission remain unclear. In columella cells of Arabidopsis roots, we previously found that cytoplasmic pH (pHc) is a mediator in early gravitropic signaling (A.C. Scott, N.S. Allen [1999] Plant Physiol 121: 1291–1298). The question arises whether pHc has a more general role in signaling gravity vector changes. Using confocal ratiometric imaging and the fluorescent pH indicator carboxy seminaphtorhodafluor acetoxymethyl ester acetate, we measured pHc in the cells composing the maize pulvinus. When stem slices were gravistimulated and imaged on a horizontally mounted confocal microscope, pHc changes were only apparent within the bundle sheath cells, and not in the parenchyma cells. After turning, cytoplasmic acidification was observed at the sides of the cells, whereas the cytoplasm at the base of the cells where plastids slowly accumulated became more basic. These changes were most apparent in cells exhibiting net amyloplast sedimentation. Parenchyma cells and isolated bundle sheath cells did not show any gravity-induced pHc changes although all cell types responded to external stimuli in the predicted way: Propionic acid and auxin treatments induced acidification, whereas raising the external pH caused alkalinization. The results suggest that pHc has an important role in the early signaling pathways of maize stem gravitropism.
The Properties of the Chlorophyll a/b-Binding Proteins Lhca2 and Lhca3 Studied in Vivo Using Antisense Inhibition
Authors: Ganeteg Ulrika , Strand Åsa , Gustafsson Petter , Jansson Stefan
Published: July 2002

The specific functions of the light-harvesting proteins Lhca2 and Lhca3 were studied in Arabidopsis ecotype Colombia antisense plants in which the proteins were individually repressed. The antisense effect was specific in each plant, but levels of Lhca proteins other than the targeted products were also affected. The contents of Lhca1 and Lhca4 were unaffected, but Lhca3 (in Lhca2-repressed plants) was almost completely depleted, and Lhca2 decreased to about 30% of wild-type levels in Lhca3-repressed plants. This suggests that the Lhca2 and Lhca3 proteins are in physical contact with each other and that they require each other for stability. Photosystem I fluorescence at 730 nm is thought to emanate from pigments bound to Lhca1 and Lhca4. However, fluorescence emission and excitation spectra suggest that Lhca2 and Lhca3, which fluoresce in vitro at 680 nm, also could contribute to far-red fluorescence in vivo. Spectral forms with absorption maxima at 695 and 715 nm, apparently with emission maxima at 702 and 735 nm, respectively, might be associated with Lhca2 and Lhca3.
V2500 technology
Authors: Ford Terry
Published: July 2002

Gives an account of the notable features and the author’s view of the main advantages of the V2500 turbofan engine from International Aero Engines.
Corrosion protection of pipes, fittings and component pieces of water treatment and pumping stations
Authors: Pey Jean‐Louis
Published: July 2002

The wide range of steel pipe sections with complex geometry, as well as that of their cast iron components (fittings, valves and pumps) poses a real problem to installation designers who must achieve a consistent level of long‐term corrosion resistance. In that case, Rilsan, Polyamide 11 coating gives the opportunity to engineering companies and subcontractors who are concerned both with the corrosion protection of pipes and with the quality of drinking water supplies to solve complex problems, such as the pipes which equip water treatment, purification and pumping stations. The application of specification and standards such as WIS 4‐52‐01(*) and NF A 49713 is the key for a long‐term solution.
The only way is up: an enhanced role for library and information services within the NHS beckons
Authors: Marriott Richard
Published: July 2002

Discusses the emergence of a climate very favourable to libraries within the UK National Health Service. Links to national policy initiatives such as clinical effectiveness, evidence based healthcare, and research and development. Quotes from key sources which cite the importance of libraries in these processes. Makes recommendations for action by librarians to exploit this new climate.
Assessment of a college freshman course in information resources
Authors: Lawson Mollie D.
Published: July 2002

Using a pre‐test and post‐test, all students enrolled in LIS 1600, Information Resources were evaluated on their library research skills. The purpose was to determine the improvement in test score on completion of the course. A newly revised university studies course was taught the first time in fall of 1996 and spring of 1997. Library Services faculty aimed to assess the effort to impart information literacy skills to freshmen students. Results of the study are reported.
Food and nutrition in the twenty‐first century curriculum
Authors: Valentine Stephanie
Published: July 2002

An evaluation of the role of food and nutrition in the school curriculum, following the recent review of the national curriculum. Opportunities in science, design and technology, home economics, citizenship, and personal, social and health education are highlighted. It is concluded that food and nutrition have a valuable contribution to make in a curriculum which is relevant to the twenty‐first century, encourages creativity and innovation, develops informed consumers and promotes good health.
Effect of pressure and solar cooking on phytic acid and polyphenol content of cowpeas
Authors: Pasrija Mamta , Punia Darshan
Published: July 2002

Both pressure cooking and solar cooking significantly reduced the phytic acid and polyphenol content of cowpea cultivars. A significantly greater reduction in the content of both these antinutrients was noticed during pressure and solar cooking of soaked cowpeas compared to unsoaked seeds. The percentage reduction increased when the soaked cowpeas were dehulled and then cooked by both pressure and solar cooking. The results of the study reveal that solar cooking was more effective than pressure cooking in reducing the concentrations of phytic acid and polyphenols in cowpeas. The cumulative effect of soaking and dehulling, followed by solar cooking, was the removal of most of the polyphenols (88‐94 per cent). Such practices should be encouraged at the home level for the preparation of cowpea seeds.
Adverse reaction to foods
Authors: Fraser O. , Sumar S. , Sumar N.
Published: July 2002

Outlines the prevalence of adverse reactions to food and what it means to the individual. Lists and describes the known main food allergies.