bluuebunny/crossref_metadata_2025 huggingface dataset:
Estimating timber depreciation in the Brazilian Amazon
Authors: MOTTA RONALDO SEROA DA , AMARAL CLAUDIO A. FERRAZ DO
Published: July 2002

This study estimates depreciation values for timber extraction activities in the Brazilian Amazon for 1990 and 1995. A generalized approach following Vincent and Hartwick (1997) is applied enabling us to calculate depreciation based on all three methods proposed in the literature. We also calculate Hotelling rents for timber as a whole and for mahogany alone. Apart from the expected differences in the results for each method, the results show substantially low depreciation estimates as a direct consequence of the high timber stocks and scarcity perception by economic agents due to the lack of property rights in the region. For mahogany alone we obtain substantially higher values. We conclude that if scarcity rents are not fully perceived, or they really do not exist in such huge supply conditions as our estimates may suggest, charges related to other forest services are fundamental to make environmental accounting an useful tool for planning in the Amazonian context.
Trade reform and environmental externalities in general equilibrium: analysis for an archetype poor tropical country
Authors: LÓPEZ RAMÓN
Published: July 2002

This paper provides a conceptual and empirical general equilibrium framework for the analysis of the impact of trade reform on welfare and the environment. The analysis is applied to Côte d'Ivoire explicitly considering externalities affecting biomass (natural vegetation), which is shown to be an important factor determining agricultural productivity.

The simulation general equilibrium analysis shows that the agricultural output composition effect dominates the agricultural expansion effect for the case of complete trade liberalization. Thus, in this case trade liberalization causes a significant improvement in the rural biomass stock by cutting land area cultivated, increases agricultural productivity, and induces dramatic welfare gains. That is, trade liberalization is a win–win type of policy in this case. However, partial trade liberalization that only reduces protection to non-agricultural goods (and does not reduce tariffs to agricultural import substitutes and does not reduce export taxes) causes a further deterioration of the biomass resources and reduces welfare.
Tropical deforestation: debt-for-nature versus debt-for-development swaps
Authors: ZAGONARI FABIO
Published: July 2002

In this paper I analyze the forest and debt dynamics in a less developed country (LDC), where the former is a renewable resource and the latter's increase results from the interests to be paid on the current debt minus the balance of trade surplus. Agricultural and industrial goods are produced, and whereas the former requires the converted forest as an input, the latter does not. It transpires that the stock of debt is likely to increase infinitely without repudiation, whereas the stock of forest is likely to oscillate around an equilibrium level. Within this framework, I compare the effectiveness and enforceability of the debt-for-nature and the debt-for-development swaps with respect to tropical deforestation and debt burden issues. Some empirical evidence confirming the theoretical results is provided.
Generative processes and the electronic arts
Authors: Dorin Alan
Published: July 2002

This paper gives a personal perspective on the application
and relevance of generative processes to art production.
This view is that of a computer programmer, rather than
that of a user of computer programs written (or
hardware constructed) by others. The programmer is in
the unique position of being able to describe and
manipulate abstract processes which may be used as a
unique means of artistic expression. This gives a greater
amount of freedom to the programmer/artist than is the
case when he or she is limited by programmed
procedures defined by others.

Prior to the development of a formal means of
specifying visual and aural events, a concrete machine or
set of rules for their manipulation and a means of
bringing these representations back into the world as
physical events, abstract processes were things to be
contemplated but not experienced. Musical and spatial
notations employed by artists, engineers and others, in
concert with the programming of computing hardware,
have opened the way for those who wish to manipulate
processes in their artistic practice.

In order to focus study and practice in the area of such
generative computer art, the Center for Electronic Media
Art (CEMA) has been established in Melbourne,
Australia. The Center has spawned an international
conference series on generative/process-based electronic
art called Iteration. The perceived roles of the Center and
Iteration conferences are discussed in this paper.
A review of time–frequency representations, with application to sound/music analysis–resynthesis
Authors: MASRI PAUL , BATEMAN ANDREW , CANAGARAJAH NISHAN
Published: July 2002

Analysis–resynthesis (A–R) systems gain their flexibility for
creative transformation of sound by representing sound as a set of musically
useful features. The analysis process extracts these features from the time
domain signal by means of a time–frequency representation (TFR). The
TFR provides an intermediate representation of sound that must make the
features accessible and measurable to the rest of the analysis. Until very
recently, the short-time Fourier transform (STFT) has been the obvious
choice for time–frequency representation, despite its limitations in
terms of resolution. Recent and ongoing developments are providing several
alternative schemes that allow for a more considered choice of TFR. This
paper reviews these contemporary approaches in comparison with the more
classical ones and with reference to their applicability, merits and
shortcomings for application to sound analysis. (Where they have been
successfully applied, details are provided.) The techniques
reviewed include linear, bilinear and higher-order spectra, nonparametric
and parametric methods and some sound-model-specific TFRs.
Ethnic Diversity Among Child and Adolescent Psychiatric (CAP) Clinic Attenders
Authors: Kramer Tami , Evans Navina , Garralda M. Elena
Published: July 2002

There is growing interest in the provision of health services that are
sensitive to the needs of diverse ethnic groups. This paper examines ethnic
diversity of attenders at a Child and Adolescent Psychiatric Clinic and how
these groups differ in terms of referral route, reason for referral, psychiatric
diagnosis and school report of difficulties. Service access relative to the
distribution of the local population is assessed. Modification of OPCS
categories provides additional useful information. The findings are relevant
for the planning and provision of child and adolescent psychiatric services
in a highly diverse population.
The State of Play in Schools
Authors: Blatchford Peter
Published: July 2002

This paper concentrates on children's play during school breaktimes.

Though neglected by researchers, it is one of the few occasions when
children can play and interact in a relatively safe environment, free of
adult
control. The paper reports on a recent programme of research at the
University of London Institute of Education. There are signs that the
prevalence of a negative view about breaktime in schools is leading to

more deliberate management and supervision of breaktimes, and a
reduction in duration. Breaktime can be a time when aggression, teasing,

and bullying take place, but this paper also reviews positive aspects of
peer
relations and games at breaktime, including opportunities for friendship

development, social competence, and peer culture. An important challenge

facing schools is achieving a balance between control over pupil
behaviour, while facilitating pupil independence and social development.
High effective inbreeding coefficients correlate with morphological abnormalities in populations of South Australian koalas (Phascolarctos cinereus)
Authors: Seymour Ayesha M. , Montgomery Margaret E. , Costello Brian H. , Ihle Sonja , Johnsson Greg , St. John Barbara , Taggart David , Houlden Bronwyn A.
Published: July 2002

Koalas have undergone a series of sequential founding events on islands in south‐eastern Australia in recent times. Populations in South Australia at the Eyre Peninsula and Mt Lofty Ranges were founded in the 1960s from a colony on Kangaroo Island. The Kangaroo Is. colony was derived from animals introduced to French Island from mainland Victoria over a century ago. In this study, we first use microsatellite markers to quantify levels of genetic variation within the South Australian koala populations and the relatively unperturbed Strzelecki Ranges population from mainland Victoria. This analysis revealed low levels of allelic diversity (1.7 ± 0.2 to 2.7 ± 0.5) and heterozygosity (0.208 ± 0.088 to 0.340 ± 0.110) in the three South Australian koala populations relative to the Strzelecki Ranges population, which has the highest levels of allelic diversity (4.7 ± 1.1) and heterozygosity (0.476 ± 0.122) in Victoria. Second, we measured the incidence of testicular aplasia, a unilateral or bilateral failure in testicular development, in the Eyre Peninsula and Kangaroo Is. populations, and in the ultimate founding population at French Is. Testicular aplasia was present at a frequency of 4.3% in French Is., 12.8% in Kangaroo Is. and 23.9% in the Eyre Peninsula, but was undetectable in the non‐bottlenecked Pilliga State Forest population of New South Wales. The incidence of testicular aplasia correlated positively with effective inbreeding coefficients derived from heterozygosity values (0.13 ± 0.06 in the Pilliga State Forest, 0.57 ± 0.17 in French Is., 0.63 ± 0.12 on Kangaroo Is. and 0.77 ± 0.12 in the Eyre Peninsula), which may indicate inbreeding depression. These findings are of concern when evaluating the long‐term conservation and viability of the South Australian koala populations, which may benefit from genetic augmentation in the future. Finally, unconfirmed reports suggested that animals from other states in Australia were introduced into the Mt Lofty Ranges population. Therefore, we quantified differentiation between the three South Australian populations and the Strzelecki Ranges and French Is. populations, based on microsatellites and mtDNA d‐loop region variation. R‐statistics and Goldstein's delta mu square distance revealed that differentiation at nuclear loci between populations paralleled known recent population history, except for the close relationship between Mt Lofty Ranges and French Is. This suggested a recent contribution to the Mt Lofty Ranges populations of animals derived from the French Is. translocation program. Furthermore, mtDNA d‐loop analysis found no evidence of contributions to the gene pool from animals of New South Wales or Queensland stock, implying that the population was derived exclusively from Victorian stock.
Down-regulation of TDT transcription in CD4+CD8+thymocytes by Ikaros proteins in direct competition with an Ets activator
Authors: Trinh Le A. , Ferrini Roger , Cobb Bradley S. , Weinmann Amy S. , Hahm Kyungmin , Ernst Patricia , Garraway Isla P. , Merkenschlager Matthias , Smale Stephen T.
Published: July 2002

Ikaros is a unique regulator of lymphopoiesis that associates with pericentromeric heterochromatin and has been implicated in heritable gene inactivation. Binding and competition experiments demonstrate that Ikaros dimers compete with an Ets activator for occupancy of the lymphocyte-specific TdT promoter. Mutations that selectively disrupt Ikaros binding to an integrated TdT promoter had no effect on promoter function in a CD4+CD8+thymocyte line. However, these mutations abolished down-regulation on differentiation, providing evidence that Ikaros plays a direct role in repression. Reduced access to restriction enzyme cleavage suggested that chromatin alterations accompany down-regulation. The Ikaros-dependent down-regulation event and the observed chromatin alterations appear to precede pericentromeric repositioning. Current models propose that the functions of Ikaros should be disrupted by a small isoform that retains the dimerization domain and lacks the DNA-binding domain. Surprisingly, in the CD4+CD8+thymocyte line, overexpression of a small Ikaros isoform had no effect on differentiation or on the pericentromeric targeting and DNA-binding properties of Ikaros. Rather, the small isoform assembled into multimeric complexes with DNA-bound Ikaros at the pericentromeric foci. The capacity for in vivo multimer formation suggests that interactions between Ikaros dimers bound to the TdT promoter and those bound to pericentromeric repeat sequences may contribute to the pericentromeric repositioning of the inactive gene.
Identification of Target Sites of the α2–Mcm1 Repressor Complex in the Yeast Genome
Authors: Zhong Hualin , McCord Ron , Vershon Andrew K.
Published: July 2002

The α2 and Mcm1 proteins bind DNA as a heterotetramer to repress transcription of cell-type-specific genes in the yeastSaccharomyces cerevisiae. Based on the DNA sequence requirements for binding by the α2–Mcm1 complex, we have searched the yeast genome for all potential α2–Mcm1 binding sites. Genes adjacent to the sites were examined for expression in the different cell mating types. These sites were further analyzed by cloning the sequences into a heterologous promoter and assaying for α2–Mcm1-dependent repression in vivo and DNA-binding affinity in vitro. Fifty-nine potential binding sites were identified in the search. Thirty-seven sites are located within or downstream of coding region of the gene. None of the sites assayed from this group are functional repressor sites in vivo or bound by the α2–Mcm1 complex in vitro. Among the remaining 22 sites, six are in the promoters of known α-specific genes and two other sites have an α2–Mcm1-dependent role in determining the direction of mating type switching. Among the remaining sequences, we have identified a functional site located in the promoter region of a previously uncharacterized gene, SCYJL170C. This site functions to repress transcription of a heterologous promoter and the α2–Mcm1 complex binds to the site in vitro. SCYJL170C is repressed by α2–Mcm1 in vivo and therefore using this method we have identified a new a-specific gene, which we callASG7.
Developmental and Stress Regulation of Gene Expression for Plastid and Cytosolic Isoprenoid Pathways in Pepper Fruits
Authors: Hugueney P. , Bouvier F. , Badillo A. , Quennemet J. , d'Harlingue A. , Camara B.
Published: July 2002

Plant cells synthesize a myriad of isoprenoid compounds in different subcellular compartments, which include the plastid, the mitochondria, and the endoplasmic reticulum cytosol. To start the study of the regulation of these parallel pathways, we used pepper (Capsicum annuum) fruit as a model. Using different isoprenoid biosynthetic gene probes from cloned cDNAs, we showed that only genes encoding the plastid enzymes (geranylgeranyl pyrophosphate synthase, phytoene synthase, phytoene desaturase, and capasanthin-capsorubin synthase) are specifically triggered during the normal period of development, at the ripening stage. This pattern of expression can be mimicked and precociously induced by a simple wounding stress. Concerning the cytosol-located enzymes, we observed that the expression of the gene encoding farnesyl pyrophosphate synthase is constitutive, whereas that of farnesyl pyrophosphate cyclase (5-epi-aristolochene synthase) is undetectable during the normal development of the fruit. The expression of these later genes are, however, only selectively triggered after elicitor treatment. The results provide evidence for developmental control of isoprenoid biosynthesis occurring in plastids and that cytoplasmic isoprenoid biosynthesis is regulated, in part, by environmental signals.
cDNA Isolation and Gene Expression of the Maize Annexins p33 and p35
Authors: Battey N. H. , James N. C. , Greenland A. J.
Published: July 2002

The isolation, cloning, and sequencing of two full-length cDNAs corresponding to the root tip forms of the maize (Zea mays L. cv Clipper) annexins p33 and p35 are described. These are the first complete sequences for the widely reported doublet of plant annexins. The predicted sequences can be divided into four repeat domains characteristic of the annexin family, but Ca2+ binding by the type-II site typical of annexins would be predicted to occur only in repeats 1 and 4. This reduced number of sites is consistent with previously reported biochemical data indicating a high Ca2+ requirement for membrane association. Although the two annexins are very similar (80% amino acid identity), their genes are quite distinct, as demonstrated by their different 3[prime] noncoding regions and Southern blotting. The predicted sequences of the root tip proteins are very similar to regions known from peptide sequencing of the coleoptile proteins. Because a rather small gene family is indicated, the implication is that there may be less functional diversity than in animal cells. Furthermore, the sequence data clearly show that plant annexins form a very distinct group compared with those from other kingdoms.
Different Phototransduction Kinetics of Phytochrome A and Phytochrome B in Arabidopsis thaliana1
Authors: Casal Jorge J. , Cerdán Pablo D. , Staneloni Roberto J. , Cattaneo Laura
Published: July 2002

The kinetics of phototransduction of phytochrome A (phyA) and phytochrome B (phyB) were compared in etiolated Arabidopsis thaliana seedlings. The responses of hypocotyl growth, cotyledon unfolding, and expression of a light-harvesting chlorophyll a/b-binding protein of the photosystem II gene promoter fused to the coding region of β-glucuronidase (used as a reporter enzyme) were mediated by phyA under continuous far-red light (FR) and by phyB under continuous red light (R). The seedlings were exposed hourly either to nmin of FR followed by 60 minus n min in darkness or ton min of R, 3 min of FR (to back-convert phyB to its inactive form), and 57 minus n min of darkness. For the three processes investigated here, the kinetics of phototransduction of phyB were faster than that of phyA. For instance, 15 min R h−1 (terminated with a FR pulse) were almost as effective as continuous R, whereas 15 min of FR h−1 caused less than 30% of the effect of continuous FR. This difference is interpreted in terms of divergence of signal transduction pathways downstream from phyA and phyB.
A Gene Coding for Tomato Fruit β-Galactosidase II Is Expressed during Fruit Ripening
Authors: Smith David L. , Starrett David A. , Gross Kenneth C.
Published: July 2002

β-Galactosidases (EC 3.2.1.23) constitute a widespread family of enzymes characterized by their ability to hydrolyze terminal, nonreducing β-d-galactosyl residues from β-d-galactosides. Several β-galactosidases, sometimes referred to asexo-galactanases, have been purified from plants and shown to possess in vitro activity against extracted cell wall material via the release of galactose from wall polymers containing β(1→4)-d-galactan. Although β-galactosidase II, a protein present in tomato (Lycopersicon esculentumMill.) fruit during ripening and capable of degrading tomato fruit galactan, has been purified, cloning of the corresponding gene has been elusive. We report here the cloning of a cDNA, pTomβgal 4 (accession no. AF020390), corresponding to β-galactosidase II, and show that its corresponding gene is expressed during fruit ripening. Northern-blot analysis revealed that the β-galactosidase II gene transcript was detectable at the breaker stage of ripeness, maximum at the turning stage, and present at decreasing levels during the later stages of normal tomato fruit ripening. At the turning stage of ripeness, the transcript was present in all fruit tissues and was highest in the outermost tissues (including the peel). Confirmation that pTomβgal 4 codes for β-galactosidase II was derived from matching protein and deduced amino acid sequences. Furthermore, analysis of the deduced amino acid sequence of pTomβgal 4 suggested a high probability for secretion based on the presence of a hydrophobic leader sequence, a leader-sequence cleavage site, and three possibleN-glycosylation sites. The predicted molecular mass and isoelectric point of the pTomβgal 4-encoded mature protein were similar to those reported for the purified β-galactosidase II protein from tomato fruit.
Decreased GA1 Content Caused by the Overexpression ofOSH1 Is Accompanied by Suppression of GA 20-Oxidase Gene Expression
Authors: Kusaba Shinnosuke , Fukumoto Masashi , Honda Chikako , Yamaguchi Isomaro , Sakamoto Tomoaki , Kano-Murakami Yuriko
Published: July 2002

We previously reported that overexpression of the rice homeobox gene OSH1 led to altered morphology and hormone levels in transgenic tobacco (Nicotiana tabacum L.) plants. Among the hormones whose levels were changed, GA1 was dramatically reduced. Here we report the results of our analysis on the regulatory mechanism(s) ofOSH1 on GA metabolism. GA53 and GA20, precursors of GA1, were applied separately to transgenic tobacco plants exhibiting severely changed morphology due to overexpression of OSH1. Only treatment with the end product of GA 20-oxidase, GA20, resulted in a striking promotion of stem elongation in transgenic tobacco plants. The internal GA1 and GA20 contents inOSH1-transformed tobacco were dramatically reduced compared with those of wild-type plants, whereas the level of GA19, a mid-product of GA 20-oxidase, was 25% of the wild-type level. We have isolated a cDNA encoding a putative tobacco GA 20-oxidase, which is mainly expressed in vegetative stem tissue. RNA-blot analysis revealed that GA 20-oxidase gene expression was suppressed in stem tissue of OSH1-transformed tobacco plants. Based on these results, we conclude that overexpression ofOSH1 causes a reduction of the level of GA1by suppressing GA 20-oxidase expression.
Photosynthetic and Heterotrophic Ferredoxin Isoproteins Are Colocalized in Fruit Plastids of Tomato
Authors: Aoki Koh , Yamamoto Miyuki , Wada Keishiro
Published: July 2002

Fruit tissues of tomato (Lycopersicon esculentum Mill.) contain both photosynthetic and heterotrophic ferredoxin (FdA and FdE, respectively) isoproteins, irrespective of their photosynthetic competence, but we did not previously determine whether these proteins were colocalized in the same plastids. In isolated fruit chloroplasts and chromoplasts, both FdA and FdE were detected by immunoblotting. Colocalization of FdA and FdE in the same plastids was demonstrated using double-staining immunofluorescence microscopy. We also found that FdA and FdE were colocalized in fruit chloroplasts and chloroamyloplasts irrespective of sink status of the plastid. Immunoelectron microscopy demonstrated that FdA and FdE were randomly distributed within the plastid stroma. To investigate the significance of the heterotrophic Fd in fruit plastids, Glucose 6-phosphate dehydrogenase (G6PDH) activity was measured in isolated fruit and leaf plastids. Fruit chloroplasts and chromoplasts showed much higher G6PDH activity than did leaf chloroplasts, suggesting that high G6PDH activity is linked with FdE to maintain nonphotosynthetic production of reducing power. This result suggested that, despite their morphological resemblance, fruit chloroplasts are functionally different from their leaf counterparts.
A Chloroplast DNA Helicase II from Pea That Prefers Fork-Like Replication Structures
Authors: Tuteja Narendra , Phan Tuan-Nghia
Published: July 2002

A DNA helicase, called chloroplast DNA (ctDNA) helicase II, was purified to apparent homogeneity from pea (Pisum sativum). The enzyme contained intrinsic, single-stranded, DNA-dependent ATPase activity and an apparent molecular mass of 78 kD on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The DNA helicase was markedly stimulated by DNA substrates with fork-like replication structures. A 5′-tailed fork was more active than the 3′-tailed fork, which itself was more active than substrates without a fork. The direction of unwinding was 3′ to 5′ along the bound strand, and it failed to unwind blunt-ended duplex DNA. DNA helicase activity required only ATP or dATP hydrolysis. The enzyme also required a divalent cation (Mg2+>Mn2+>Ca2+) for its unwinding activity and was inhibited at 200 mm KCl or NaCl. This enzyme could be involved in the replication of ctDNA. The DNA major groove-intercalating ligands nogalamycin and daunorubicin were inhibitory to unwinding (K  i approximately 0.85 μm and 2.2 μm, respectively) and ATPase (K  i approximately 1.3 μm and 3.0 μm, respectively) activities of pea ctDNA helicase II, whereas ellipticine, etoposide (VP-16), and camptothecin had no effect on the enzyme activity. These ligands may be useful in further studies of the mechanisms of chloroplast helicase activities.
Differential Expression of Three Members of the 1-Aminocyclopropane-1-Carboxylate Synthase Gene Family in Carnation1
Authors: Jones Michelle L. , Woodson William R.
Published: July 2002

We investigated the expression patterns of three 1-aminocyclopropane-1-carboxylate (ACC) synthase genes in carnation (Dianthus caryophyllus cv White Sim) under conditions previously shown to induce ethylene biosynthesis. These included treatment of flowers with 2,4-dichlorophenoxyacetic acid, ethylene, LiCl, cycloheximide, and natural and pollination-induced flower senescence. Accumulation of ACC synthase transcripts in leaves following mechanical wounding and treatment with 2,4-dichlorophenoxyacetic acid or LiCl was also determined by RNA gel-blot analysis. As in other species, the carnation ACC synthase genes were found to be differentially regulated in a tissue-specific manner. DCACS2 and DCACS3 were preferentially expressed in styles, whereas DCACS1 mRNA was most abundant in petals. Cycloheximide did not induce increased accumulation of ACC synthase transcripts in carnation flowers, whereas the expression of ACC synthase was up-regulated by auxin, ethylene, LiCl, pollination, and senescence in a floral-organ-specific manner. Expression of the three ACC synthases identified in carnation did not correspond to elevated ethylene biosynthesis from wounded or auxin-treated leaves, and there are likely additional members of the carnation ACC synthase gene family responsible for ACC synthase expression in vegetative tissues.
Identification, Separation, and Characterization of Acyl-Coenzyme A Dehydrogenases Involved in Mitochondrial β-Oxidation in Higher Plants1
Authors: Bode Kornelia , Hooks Mark A. , Couée Ivan
Published: July 2002

The existence in higher plants of an additional β-oxidation system in mitochondria, besides the well-characterized peroxisomal system, is often considered controversial. Unequivocal demonstration of β-oxidation activity in mitochondria should rely on identification of the enzymes specific to mitochondrial β-oxidation. Acyl-coenzyme A dehydrogenase (ACAD) (EC 1.3.99.2,3) activity was detected in purified mitochondria from maize (Zea mays L.) root tips and from embryonic axes of early-germinating sunflower (Helianthus annuus L.) seeds, using as the enzyme assay the reduction of 2,6-dichlorophenolindophenol, with phenazine methosulfate as the intermediate electron carrier. Subcellular fractionation showed that this ACAD activity was associated with mitochondrial fractions. Comparison of ACAD activity in mitochondria and acyl-coenzyme A oxidase activity in peroxisomes showed differences of substrate specificities. Embryonic axes of sunflower seeds were used as starting material for the purification of ACADs. Two distinct ACADs, with medium-chain and long-chain substrate specificities, respectively, were separated by their chromatographic behavior, which was similar to that of mammalian ACADs. The characterization of these ACADs is discussed in relation to the identification of expressed sequenced tags corresponding to ACADs in cDNA sequence analysis projects and with the potential roles of mitochondrial β-oxidation in higher plants.
Gradients in Water Potential and Turgor Pressure along the Translocation Pathway during Grain Filling in Normally Watered and Water-Stressed Wheat Plants
Authors: Fisher Donald B. , Cash-Clark Cora E.
Published: July 2002

The water relations parameters involved in assimilate flow into developing wheat (Triticum aestivum L.) grains were measured at several points from the flag leaf to the endosperm cavity in normally watered (Ψ ≈ −0.3 MPa) and water-stressed plants (Ψ ≈ −2 MPa). These included direct measurement of sieve tube turgor and several independent approaches to the measurement or calculation of water potentials in the peduncle, grain pericarp, and endosperm cavity. Sieve tube turgor measurements, osmotic concentrations, and Ψ measurements using dextran microdrops showed good internal consistency (i.e. Ψ = Ψs + Ψp) from 0 to −4 MPa. In normally watered plants, crease pericarp Ψ and sieve tube turgor were almost 1 MPa lower than in the peduncle. This suggests a high hydraulic resistance in the sieve tubes connecting the two. However, observations concerning exudation rates indicated a low resistance. In water-stressed plants, peduncle Ψ and crease pericarp Ψ were similar. In both treatments, there was a variable, approximately 1-MPa drop in turgor pressure between the grain sieve tubes and vascular parenchyma cells. There was little between-treatment difference in endosperm cavity sucrose or osmotic concentrations or in the crease pericarp sucrose pool size. Our results re-emphasize the importance of the sieve tube unloading step in the control of assimilate import.
Regulation of a Plant SNF1-Related Protein Kinase by Glucose-6-Phosphate
Authors: Toroser Dikran , Plaut Zvi , Huber Steven C.
Published: July 2002

One of the major protein kinases (PKIII) that phosphorylates serine-158 of spinach sucrose-phosphate synthase (SPS), which is responsible for light/dark modulation of activity, is known to be a member of the SNF1-related family of protein kinases. In the present study, we have developed a fluorescence-based continuous assay for measurement of PKIII activity. Using the continuous assay, along with the fixed-time-point 32P-incorporation assay, we demonstrate that PKIII activity is inhibited by glucose-6-phosphate (Glc-6-P). Relative inhibition by Glc-6-P was increased by decreasing pH from 8.5 to 5.5 and by reducing the concentration of Mg2+ in the assay from 10 to 2 mm. Under likely physiological conditions (pH 7.0 and 2 mm Mg2+), 10 mm Glc-6-P inhibited kinase activity approximately 70%. Inhibition by Glc-6-P could not be ascribed to contaminants in the commercial preparations. Other metabolites inhibited PKIII in the following order: Glc-6-P > mannose-6-P, fructose-1,6P2 > ribose-5-P, 3-PGA, fructose-6-P. Inorganic phosphate, Glc, and AMP were not inhibitory, and free Glc did not reverse the inhibition by Glc-6-P. Because SNF1-related protein kinases are thought to function broadly in the regulation of enzyme activity and gene expression, Glc-6-P inhibition of PKIII activity potentially provides a mechanism for metabolic regulation of the reactions catalyzed by these important protein kinases.
Specific Lipoxygenase Isoforms Accumulate in Distinct Regions of Soybean Pod Walls and Mark a Unique Cell Layer
Authors: Dubbs Wesley E. , Grimes Howard D.
Published: July 2002

Developing seeds constitute a strong sink for the plant and rely on the turnover and mobilization of carbon and nitrogen assimilates to supply the nutrients needed for their maturation. In large part these nutrients emanate from the vegetative organs including leaves and pod walls. Vegetative lipoxygenases (VLXs) accumulate in the paraveinal mesophyll cell layer of soybean (Glycine max L.) leaves where individual isoforms are proposed to play a role(s) as active enzymes or as transient storage proteins. VLXs also are prominent proteins in soybean pod walls, representing approximately 12% of the total soluble protein. Examining the temporal, tissue, and subcellular patterns of individual VLX isoform accumulation and of lipoxygenase activity through pod wall development indicates that VLXD is the principal VLX isoform playing a role in storage in this organ. The major accumulation of VLXD occurs just prior to seed fill within the endocarp middle zone, and protein extracted from this region shows relatively low levels of lipoxygenase activity, suggesting the middle zone may act as a storage tissue. Three other VLX isoforms, VLXA, VLXB, and VLXC colocalize to the cytoplasm of a single discrete cell layer in the mesocarp. Thus, the patterns of VLX cellular and subcellular localization in pod walls suggest independent functions for these different isoforms while also serving as specific markers for a novel cell layer in the pod wall.
Direct Evidence for Requirement of Phosphatidylglycerol in Photosystem II of Photosynthesis
Authors: Hagio Miki , Gombos Zoltán , Várkonyi Zsuzsanna , Masamoto Kazumori , Sato Norihiro , Tsuzuki Mikio , Wada Hajime
Published: July 2002

Phosphatidylglycerol (PG) is considered to play an important role in the ordered assembly and structural maintenance of the photosynthetic apparatus in thylakoid membranes. However, its function in photosynthesis remains poorly understood. In this study we have identified a pgsA gene of Synechocystissp. PCC6803 that encodes a PG phosphate synthase involved in the biosynthesis of PG. A disruption of the pgsA gene allowed us to manipulate the content of PG in thylakoid membranes and to investigate the function of PG in photosynthesis. The obtainedpgsA mutant could grow only in the medium containing PG, and the photosynthetic activity of the pgsA mutant dramatically decreased with a concomitant decrease of PG content in thylakoid membranes when the cells grown in the presence of PG were transferred to the medium without PG. This decrease of photosynthetic activity was attributed to the decrease of photosystem (PS)II activity, but not to the decrease in PSI activity. These findings demonstrate that PG is essential for growth of Synechocystis sp. PCC6803 and provide the first direct evidence that PG plays an important role in PSII.
Ultraviolet-B Radiation Impacts Light-Mediated Turnover of the Photosystem II Reaction Center Heterodimer in Arabidopsis Mutants Altered in Phenolic Metabolism
Authors: Booij-James Isabelle S. , Dube Shyam K. , Jansen Marcel A.K. , Edelman Marvin , Mattoo Autar K.
Published: July 2002

Ultraviolet-B (UV-B) radiation can have a negative impact on the growth and development of plants. Plants tolerant to UV-B alleviate these effects using UV-screening pigments that reduce the penetration of UV-B into mesophyll tissue. Little is known about the relative contribution of specific phenolic compounds to the screening capacity of leaves. The D1 and D2 proteins constituting the photosystem (PS) II reaction center heterodimer are targets of UV-B radiation and can be used as an in situ sensor for UV penetration into photosynthetic tissue. Degradation of these proteins occurs under very low fluences of UV-B, and is strongly accelerated in the presence of visible light. Using the D1-D2 degradation assay, we characterized UV-B sensitivity of Arabidopsis mutants (tt4, tt5, andfah1) that are genetically altered in their composition of phenolic compounds. We found that changes in phenol metabolism result in altered rates of PSII reaction center heterodimer degradation under mixtures of photosynthetically active radiation and UV-B. A comparison of D2 degradation kinetics showed increased UV sensitivity of the Landsberg (Landsberg erecta) tt5mutant relative to the Landsberg tt4 mutant and the Landsberg wild type. Despite a lack of flavonoid accumulation, thett4 mutant is not particularly UV sensitive. However, the tolerance of this mutant to UV-B may reflect the increased accumulation of sinapate esters that strongly absorb in the UV range, and may thus protect the plant against environmentally relevant UV-B radiation. This sinapate-mediated protection is less obvious for thett4 mutant of Columbia ecotype, indicating that the relative contribution of particular phenolics to the total screening capacity varies with the genetic background. The role of sinapate esters in UV screening is further substantiated by the results with thefah1 mutant where absence of most of the sinapate esters results in a significantly accelerated degradation of D2 under mixed light conditions. Because the latter mutant is not expected to be deficient in flavonoids, the relative contribution of flavonoids as protectants of PSII reaction center heterodimer against UV-B damage in Arabidopsis needs to be re-evaluated vis-a-vis screening by simple phenolics like sinapate esters.
Transgenic Arabidopsis Plants with Decreased Activity of Fructose-6-Phosphate,2-Kinase/Fructose-2,6-Bisphosphatase Have Altered Carbon Partitioning
Authors: Draborg Henriette , Villadsen Dorthe , Nielsen Tom Hamborg
Published: July 2002

The role of fructose-2,6-bisphosphate (Fru-2,6-P2) as a regulatory metabolite in photosynthetic carbohydrate metabolism was studied in transgenic Arabidopsis plants with reduced activity of Fru-6-phosphate,2-kinase/Fru-2,6-bisphosphatase. A positive correlation was observed between the Fru-6-phosphate,2-kinase activity and the level of Fru-2,6-P2 in the leaves. The partitioning of carbon was studied by 14CO2 labeling of photosynthetic products. Plant lines with Fru-2,6-P2 levels down to 5% of the levels observed in wild-type (WT) plants had significantly altered partitioning of carbon between sucrose (Suc) versus starch. The ratio of 14C incorporated into Suc and starch increased 2- to 3-fold in the plants with low levels of Fru-2,6-P2 compared with WT. Transgenic plant lines with intermediate levels of Fru-2,6-P2 compared with WT had a Suc-to-starch labeling ratio similar to the WT. Levels of sugars, starch, and phosphorylated intermediates in leaves were followed during the diurnal cycle. Plants with low levels of Fru-2,6-P2 in leaves had high levels of Suc, glucose, and Fru and low levels of triose phosphates and glucose-1-P during the light period compared with WT. During the dark period these differences were eliminated. Our data provide direct evidence that Fru-2,6-P2 affects photosynthetic carbon partitioning in Arabidopsis. Opposed to this, Fru-2,6-P2 does not contribute significantly to regulation of metabolite levels in darkness.
Major Alterations of the Regulation of Root NO3
− Uptake Are Associated with the Mutation of Nrt2.1 and Nrt2.2 Genes in Arabidopsis
Authors: Cerezo Miguel , Tillard Pascal , Filleur Sophie , Muños Stéphane , Daniel-Vedele Françoise , Gojon Alain
Published: July 2002

The role of AtNrt2.1 and AtNrt2.2genes, encoding putative NO3  − transporters in Arabidopsis, in the regulation of high-affinity NO3  − uptake has been investigated in theatnrt2 mutant, where these two genes are deleted. Our initial analysis of the atnrt2 mutant (S. Filleur, M.F. Dorbe, M. Cerezo, M. Orsel, F. Granier, A. Gojon, F. Daniel-Vedele [2001] FEBS Lett 489: 220–224) demonstrated that root NO3  − uptake is affected in this mutant due to the alteration of the high-affinity transport system (HATS), but not of the low-affinity transport system. In the present work, we show that the residual HATS activity in atnrt2 plants is not inducible by NO3  −, indicating that the mutant is more specifically impaired in the inducible component of the HATS. Thus, high-affinity NO3  − uptake in this genotype is likely to be due to the constitutive HATS. Root15NO3  − influx in theatnrt2 mutant is no more derepressed by nitrogen starvation or decrease in the external NO3  −availability. Moreover, the mutant also lacks the usual compensatory up-regulation of NO3  − uptake in NO3  −-fed roots, in response to nitrogen deprivation of another portion of the root system. Finally, exogenous supply of NH4  + in the nutrient solution fails to inhibit 15NO3  − influx in the mutant, whereas it strongly decreases that in the wild type. This is not explained by a reduced activity of NH4  +uptake systems in the mutant. These results collectively indicate thatAtNrt2.1 and/or AtNrt2.2 genes play a key role in the regulation of the high-affinity NO3  − uptake, and in the adaptative responses of the plant to both spatial and temporal changes in nitrogen availability in the environment.
Corrosion of copper metal in distillation process
Authors: Keera Safaa T. , Eissa Elham A. , Taman Afaf R.
Published: July 2002

Corrosion in atmospheric distillation is caused by hydrochloric acid produced by the hydrolysis of water soluble magnesium and calcium chlorides found in the crude oil. Corrosion of copper metal during distillation of Geisum crude oil (vapour phase ) at 100, 150, 200, 250, and 300°C in absence and presence of 5 per cent H2O was studied. The corrosion of copper metal in the vapour phase is higher than in the liquid phase. Hydrogen sulphide is not the only corrodant present; hydrogen chloride and volatile acids are other important corrodants. The effect of adding different inhibitors with various concentrations on the corrosion of copper metal was also studied. The rate of inhibition increases with addition of chlorinated hexadecylamine as compared with that obtained by addition of ammonia alone. The inhibitive efficiency of copper increased rapidly as the copper benzotriazole film grows rapidly.
Synergistic and biocidal effects of 1‐hydroxyethane ‐1, 1‐diphosphate, Zn2+ and polycrylamide on the inhibition of corrosion of mild steel in neutral aqueous environment
Authors: Rajendran S. , Apparao B.V. , Palaniswamy N.
Published: July 2002

The formulation consisting of 300ppm 1‐hydroxyethane‐1, 1‐diphosphonic acid (HEDP), 50ppm polyacrylamide (PAA) and 50 ppm Zn2+ offered 99 per cent corrosion inhibition and 99 to 99.9 per cent biocidal inhibition to mild steel in neutral aqueous environment containing 60ppm Cl‐ , a situation commonly encountered in cooling water systems. The nature of the protective film formed on the metal surface was analysed using X‐ray diffraction, UV‐visible reflectance, FTIR and luminescence spectra. The film was found to be luminescent and to consist of Fe2+ ‐HEDP complex, Fe2+ ‐PAA complex and Zn(OH)2.
The key to perfect presentations
Authors: Aziz Khalid
Published: July 2002

Recent research from The Aziz Corporation shows that training managers are clued up when it comes to the need for presentation training and its benefits, yet those who are most in need of this help are still missing out. This article argues that spoken communications must be given more attention and suggests how training officers can ensure these valuable skills are targeted at the right people throughout the organisation. In addition, the article contains practical advice for preparing and delivering the perfect presentation, applicable to professionals across all sectors and at all levels of the organisation.
Children’s drinks ‐ what children really think
Authors: Duff Rosemary
Published: July 2002

This paper discusses the findings of a market research programme carried out by SMRC ChildWise on behalf of Tetra Pak UK Ltd, examining use of and attitudes to soft drinks among children and mothers. This is a product field of increasing interest to children as they grow, and their appreciation develops from being totally product‐focused, to include packaging and then brand considerations. The research examined behaviour across the key drinking occasions that make up the child’s day, looking in detail at drinks consumed at school. It is at school that a child’s freedom of choice develops, and awareness of peer group influences becomes increasingly important. Children are highly receptive to new brands and flavours, but also demand professional packaging and promotional input for brands to be credible. Younger children appreciate having their own individual carton with a straw but, for older boys, a can is preferred, whilst girls like the practicalities of resealable bottles.
Projecting a career: industry and education working together in
Bexley
Authors: Churchill Sue
Published: July 2002

Examines the effectiveness of a one‐day education/business
initiative set up in 1994 in South London under the auspices of the
South London Training & Enterprise Council, and Bexley Education
Business Partnership. The 16‐17‐year‐olds were divided into teams or
businesses and invited to tender for a marketing contract to promote
Bastille Day at the Swallow Hotel. The one‐day exercise involved
drafting a promotional leaflet in French, writing an advertisement,
making a leaflet holder and, finally, giving a presentation. Concludes
that the initiative successfully encouraged teamwork and leadership,
while enabling young people to practise the work‐related skills which
employers value. It also provided an opportunity to take on a high‐level
management/marketing challenge – an activity outside their
experience – and see for themselves how different industries
interrelate.
Software planning of assembly lines
Authors: Rooks Brian
Published: July 2002

The article introduces eM‐Assembly, one of the new generic computer aided production engineering solutions from Tecnomatix. The solution incorporates a number of modules to plan, optimise and apply discrete event simulation to the layout and sequence of assembly lines. The physical mating of parts may be continuously simulated in another module and any collisions detected. The use of the eM‐Plant module to assist a Japanese camera manufacturer in planning a new assembly line is discussed and the benefits achieved in improving throughput and saving on capital highlighted. Brief details are also given of achievements by two other users.
Industrial applications of nuclear magnetic resonance
Authors: Hammer Bruce E.
Published: July 2002

During the past 50 years the phenomenon of nuclear magnetic resonance (NMR) has evolved from a scientific curiosity to a powerful analytical tool for physical scientists and the medical community. Its primary use is for analytical chemistry and medical imaging. NMR imaging and spectroscopy can non‐invasively and non‐destructively examine the physical and chemical composition of materials. The technology is now at a level of sophistication and maturity where industrial applications are possible. This article describes the basis of NMR imaging and spectroscopy and examines the application of NMR to a broad range of industrial applications.
Annual CREMRU‐JCI survey of corporate real estate practices in Europe and North America: 1993‐1998
Authors: Bon Ranko , Luck Rachael
Published: July 2002

The annual survey of corporate real estate practices has been conducted by CREMRU since 1993, and in collaboration with JCI since 1997. The survey has been supported by IDRC and NACORE, two leading professional associations concerned with corporate real estate. This summary of the six annual surveys focuses on the incidence of corporate real estate management (CREM) policies, functions and activities, as well as the assessment of knowledge or skills relevant to the CREM function in the future. Both are of vital interest to educational institutions concerned with this field, as well as the personnel and training functions within organizations concerned with better management of their property.
EDI use and participation models: from the inter‐organizational relationship perspective
Authors: Jun Minjoon , Cai Shaohan , Peterson Robin T.
Published: July 2002

Electronic Data Interchange (EDI) is an inter‐organizational information system that requires collaboration and commitment between trading partners. The potential benefits that EDI can offer are substantial. However, the adoption and use of electronic linkages between companies is not as simple, or as profitable as had been expected. This study developed three conceptual models based on four important EDI measurements: EDI volume, diversity, depth, and breadth. Next, this research identified and discussed the evolutionary procedures of and the magnitude of EDI participation that companies tend to adopt in the context of the various environmental factors. Finally, this study produced a number of managerial implications and recommendations.