bluuebunny/crossref_metadata_2025_split huggingface dataset:
The environment of ageing
Authors: Tinker Anthea 
Published: October 2002

The issue of housing and the wider environment for an ageing population is one where there are many unanswered questions. In this paper a number of key issues are discussed and for each of these the focus is on three aspects. These are the current situation, its reasonableness and what research is needed in order to make decisions about policy and practice.The first three issues relate to the profile of older people themselves and the importance of home to them. The changing profile of older people is not just about an ageing population but also about the growing prominence of those with dementia, women, people from black and ethnic minority groups and one person households, yet little is known about the type of housing which should be provided. Of equal concern is the widening gap between those with a high standard of living (including housing) and those with a low standard of living. The importance of home to older people means that research must focus on how people can be enabled to remain there, and also on the costs, financial and otherwise, to carers and to society.The next three issues relate to the type of housing older people live in and moves in later life. The startling change in the tenure pattern with a growth of owner occupation brings problems as does the decline in social housing. The advantages and disadvantages of the different types of housing, mainstream and specialized—for older people are relatively well known. However the balance between the two needs more research as does that on retirement communities. While it is well known that there are peaks of migration in old age and that moves are often made in haste, little is known about the process of decision making.The final two topics concern links between housing and other aspects of older people's lives. On health more research is needed on temperature, mortality and morbidity, homelessness and accidents and especially on links between services.These topics have implications for planning and design. The emphasis should be on a multidisciplinary approach using a variety of quantitative and qualitative techniques with an emphasis on dissemination.
High-Level and Ubiquitous Expression of the Rice CytochromecGeneOsCc1and Its Promoter Activity in Transgenic Plants Provides a Useful Promoter for Transgenesis of Monocots
Authors: Jang In-Cheol , Choi Won-Bin , Lee Kyung-Hee , Song Sang Ik , Nahm Baek Hie , Kim Ju-Kon 
Published: October 2002

AbstractExpression patterns of a rice (Oryza sativa) cytochrome c gene OsCc1 and its promoter activity were characterized in transgenic rice plants.OsCc1 transcripts accumulate in most cell types, but to varying levels. Large amounts of OsCc1 transcripts are found in the roots, calli, and suspension cells, but relatively lower in mature leaves, demonstrating its higher levels of expression in non-photosynthetic tissues. Unlike the human cytochromec gene, which is responsive to cAMP,OsCc1 expression is not enhanced in various rice tissues after dibutyryl cAMP treatments. OsCc1 promoter was linked to the sgfp gene and its activities in different tissues and cell types of transgenic rice plants were analyzed in comparison with the Act1 and RbcSpromoters. OsCc1 promoter directs expression in virtually all organs of transgenic plants including roots, leaves, calli, embryos, and suspension cells, showing a particularly high activity in calli and roots. Activity of the OsCc1promoter was 3-fold higher than Act1 in calli and roots and comparable with RbcS in leaves, representing a useful alternative to the maize (Zea mays)Ubi1 and the rice Act1 promoters for transgene expression in monocots.
How Closely Do the δ13C Values of Crassulacean Acid Metabolism Plants Reflect the Proportion of CO2 Fixed during Day and Night?
Authors: Winter Klaus , Holtum Joseph A.M. 
Published: October 2002

Abstract
The extent to which Crassulacean acid metabolism (CAM) plant δ13C values provide an index of the proportions of CO2 fixed during daytime and nighttime was assessed. Shoots of seven CAM species (Aloe vera, Hylocereus monocanthus, Kalanchoe beharensis,Kalanchoe daigremontiana, Kalanchoe pinnata, Vanilla pauciflora, andXerosicyos danguyi) and two C3 species (teak [Tectona grandis] and Clusia sp.) were grown in a cuvette, and net CO2 exchange was monitored for up to 51 d. In species exhibiting net dark CO2fixation, between 14% and 73.3% of the carbon gain occurred in the dark. δ13C values of tissues formed inside the cuvette ranged between −28.7‰ and −11.6‰, and correlated linearly with the percentages of carbon gained in the light and in the dark. The δ13C values for new biomass obtained solely during the dark and light were estimated as −8.7‰ and −26.9‰, respectively. For each 10% contribution of dark CO2 fixation integrated over the entire experiment, the δ13C content of the tissue was, thus, approximately 1.8‰ less negative. Extrapolation of the observations to plants previously surveyed under natural conditions suggests that the most commonly expressed version of CAM in the field, “the typical CAM plant,” involves plants that gain about 71% to 77% of their carbon by dark fixation, and that the isotopic signals of plants that obtain one-third or less of their carbon in the dark may be confused with C3 plants when identified on the basis of carbon isotope content alone.
Transgenic Plant Cells Lacking Mitochondrial Alternative Oxidase Have Increased Susceptibility to Mitochondria-Dependent and -Independent Pathways of Programmed Cell Death
Authors: Robson Christine A. , Vanlerberghe Greg C. 
Published: October 2002

AbstractThe plant mitochondrial electron transport chain is branched such that electrons at ubiquinol can be diverted to oxygen via the alternative oxidase (AOX). This pathway does not contribute to ATP synthesis but can dampen the mitochondrial generation of reactive oxygen species. Here, we establish that transgenic tobacco (Nicotiana tabacum L. cv Petit Havana SR1) cells lacking AOX (AS8 cells) show increased susceptibility to three different death-inducing compounds (H2O2, salicylic acid [SA], and the protein phosphatase inhibitor cantharidin) in comparison with wild-type cells. The timing and extent of AS8 cell death are very similar among the three treatments and, in each case, are accompanied by the accumulation of oligonucleosomal fragments of DNA, indicative of programmed cell death. Death induced by H2O2 or SA occurs by a mitochondria-dependent pathway characterized by cytochrome c release from the mitochondrion. Conversely, death induced by cantharidin occurs by a pathway without any obvious mitochondrial involvement. The ability of AOX to attenuate these death pathways may relate to its ability to maintain mitochondrial function after insult with a death-inducing compound or may relate to its ability to prevent chronic oxidative stress within the mitochondrion. In support of the latter, long-term treatment of AS8 cells with an antioxidant compound increased the resistance of AS8 cells to SA- or cantharidin-induced death. The results indicate that plants maintain both mitochondria-dependent and -independent pathways of programmed cell death and that AOX may act as an important mitochondrial “survival protein” against such death.
O-Methyltransferases Involved in the Biosynthesis of Volatile Phenolic Derivatives in Rose Petals
Authors: Lavid Noa , Wang Jihong , Shalit Moshe , Guterman Inna , Bar Einat , Beuerle Till , Menda Naama , Shafir Sharoni , Zamir Dani , Adam Zach , Vainstein Alexander , Weiss David , Pichersky Eran , Lewinsohn Efraim 
Published: October 2002

AbstractRose (Rosa hybrida) flowers produce and emit a diverse array of volatiles, characteristic to their unique scent. One of the most prominent compounds in the floral volatiles of many rose varieties is the methoxylated phenolic derivative 3,5-dimethoxytoluene (orcinol dimethyl ether). Cell-free extracts derived from developing rose petals displayedO-methyltransferase (OMT) activities toward several phenolic substrates, including 3,5-dihydroxytoluene (orcinol), 3-methoxy,5-hydroxytoluene (orcinol monomethyl ether), 1-methoxy, 2-hydroxy benezene (guaiacol), and eugenol. The activity was most prominent in rose cv Golden Gate, a variety that produces relatively high levels of orcinol dimethyl ether, as compared with rose cv Fragrant Cloud, an otherwise scented variety but which emits almost no orcinol dimethyl ether. Using a functional genomics approach, we have identified and characterized two closely related cDNAs from a rose petal library that each encode a protein capable of methylating the penultimate and immediate precursors (orcinol and orcinol monomethyl ether, respectively) to give the final orcinol dimethyl ether product. The enzymes, designated orcinol OMTs (OOMT1 and OOMT2), are closely related to other plant methyltransferases whose substrates range from isoflavones to phenylpropenes. The peak in the levels ofOOMT1 and OOMT2 transcripts in the flowers coincides with peak OMT activity and with the emission of orcinol dimethyl ether.
Physiological and Molecular Biological Characterization of Intracellular Carbonic Anhydrase from the Marine DiatomPhaeodactylum tricornutum
Authors: Satoh Dan , Hiraoka Yasutaka , Colman Brian , Matsuda Yusuke 
Published: October 2002

Abstract
A single intracellular carbonic anhydrase (CA) was detected in air-grown and, at reduced levels, in high CO2-grown cells of the marine diatom Phaeodactylum tricornutum (UTEX 642). No external CA activity was detected irrespective of growth CO2 conditions. Ethoxyzolamide (0.4 mm), a CA-specific inhibitor, severely inhibited high-affinity photosynthesis at low concentrations of dissolved inorganic carbon, whereas 2 mm acetazolamide had little effect on the affinity for dissolved inorganic carbon, suggesting that internal CA is crucial for the operation of a carbon concentrating mechanism in P. tricornutum. Internal CA was purified 36.7-fold of that of cell homogenates by ammonium sulfate precipitation, and two-step column chromatography on diethylaminoethyl-sephacel andp-aminomethylbenzene sulfone amide agarose. The purified CA was shown, by SDS-PAGE, to comprise an electrophoretically single polypeptide of 28 kD under both reduced and nonreduced conditions. The entire sequence of the cDNA of this CA was obtained by the rapid amplification of cDNA ends method and indicated that the cDNA encodes 282 amino acids. Comparison of this putative precursor sequence with the N-terminal amino acid sequence of the purified CA indicated that it included a possible signal sequence of up to 46 amino acids at the N terminus. The mature CA was found to consist of 236 amino acids and the sequence was homologous to β-type CAs. Even though the zinc-ligand amino acid residues were shown to be completely conserved, the amino acid residues that may constitute a CO2-binding site appeared to be unique among the β-CAs so far reported.
Modification of Expansin Transcript Levels in the Maize Primary Root at Low Water Potentials
Authors: Wu Yajun , Thorne Eleanor T. , Sharp Robert E. , Cosgrove Daniel J. 
Published: October 2002

Abstract
We previously demonstrated that maintenance of cell elongation in the apical region of maize primary roots at low water potentials (ψw) was associated with an increase in expansin activity and extractable expansin protein. Here, we characterized the spatial pattern of expansin gene expression along the growing maize root and studied the effect of low ψw on expansin gene expression. Roots were divided into three segments: apical 0 to 5 mm, subapical 5 to 10 mm, and non-growing 10 to 20 mm. Of the five expansin genes expressed in control roots, two α-expansins (Exp1 andExp5) and two β-expansins (ExpB2 andExpB8) are expressed specifically in the growing region, whereas expression of β-expansin ExpB6 is shifted basipetally. After seedlings were transplanted to vermiculite with a ψw of −1.6 MPa, transcripts forExp1, Exp5, and ExpB8rapidly accumulated in the apical region of the root. These mRNA changes correlated with the maintenance of root elongation and increases in wall extensibility found previously. The β-expansinsExpB2 and ExpB6 showed distinctive patterns of expression and responses to low ψw,indicative of distinctive functions. Inhibition of abscisic acid (ABA) accumulation at low ψw (by fluridone treatment) had no effect on expansin expression, except that ExpB2transcript level showed a minor dependence on ABA. Gene-specific regulation of α- and β-expansin mRNA pools likely contributes to growth alterations of the maize (Zea mays) root as it adapts to a low ψw, but these changes do not appear to be mediated by changes in ABA content.
Plasma Membrane Phosphatidylinositol 4,5-Bisphosphate Levels Decrease with Time in Culture
Authors: Heilmann Ingo , Perera Imara Y. , Gross Wolfgang , Boss Wendy F. 
Published: October 2002

Abstract
During the stationary phase of growth, after 7 to 12 d in culture, the levels of phosphatidylinositol 4,5-bisphosphate (PtdInsP2) decreased by 75% in plasma membranes of the red alga Galdieria sulphuraria. Concomitant with the decrease in PtdInsP2 levels in plasma membranes, there was an increase in PtdInsP2 in microsomes, suggesting that the levels of plasma membrane PtdInsP2 are regulated differentially. The decline of PtdInsP2 in plasma membranes was accompanied by a 70% decrease in the specific activity of PtdInsP kinase and by reduced levels of protein cross-reacting with antisera against a conserved PtdInsP kinase domain. Upon osmotic stimulation, the loss of PtdInsP2from the plasma membrane increased from 10% in 7-d-old cells to 60% in 12-d-old cells, although the levels of inositol 1,4,5-trisphosphate (InsP3) produced in whole cells were roughly equal at both times. When cells with low plasma membrane PtdInsP2 levels were osmotically stimulated, a mild osmotic stress (12.5 mm KCl) activated PtdInsP kinase prior to InsP3 production, whereas in cells with high plasma membrane PtdInsP2, more severe stress (250 mm KCl) was required to induce an increase in PtdInsP kinase activity. The differential regulation of a plasma membrane signaling pool of PtdInsP2 is discussed with regard to the implications for understanding the responsive state of cells.
Expression of 35S::Pto Globally Activates Defense-Related Genes in Tomato Plants
Authors: Xiao Fangming , Tang Xiaoyan , Zhou Jian-Min 
Published: October 2002

Abstract
The tomato (Lycopersicon esculentum) resistance genePto confers resistance to the bacterial pathogenPseudomonas syringae pv tomato carrying the avirulent gene avrPto. OverexpressingPto under the control of the cauliflower mosaic virus 35S promoter constitutively activates defense responses in the absence of pathogen infection and nonspecifically enhances disease resistance. To elucidate the mechanisms underlying this resistance, we isolated cDNAs corresponding to transcripts that accumulated in 35S::Pto plants. By using suppression subtractive hybridization, we isolated 82 unique cDNA clones, most of which corresponded to differentially expressed transcripts. Most of the genes examined were also induced by pathogen inoculation. Sequence analysis showed that a large number of genes encode defense-related proteins, and most had not been previously isolated from tomato. The isolated cDNAs also include those with a putative role in the oxidative burst, proteolysis, the hypersensitive response, signal transduction, and a number of genes with unknown functions. The isolation of these cDNAs of diverse functions will assist in the characterization of defense pathways activated during disease resistance.
Diffuse X-ray scattering and reverse Monte Carlo simulation of the short-range order in ytterbium iodine phthalocyanine [YbPc2]I2
Authors: Krawczyk J. , Pietraszko A. , Łukaszewicz K. 
Published: October 2002

Iodine-doped ytterbium phthalocyanine, C64H32N16YbI2, [YbPc2]I2 (YPI), presents an example of a disordered modulated crystal structure of the intergrowth type. The short-range order in YPI has been studied at ambienttemperature by the diffuse X-ray scattering technique. Both Yb and I atoms are disordered. In a unit cell of the average structure, the Yb atoms occupy two positions, \textstyle {{1} \over {2}}, \textstyle {{1} \over {2}}, \textstyle {{1} \over {4}} or \textstyle {{1} \over {2}}, \textstyle {{1} \over {2}}, \textstyle {{3} \over {4}}, with occupancy 0.5. In the neighbouring unit cells in the (001) plane there is, however, a strong tendency towards an alternating distribution of ytterbium in positions shifted by Δz = \textstyle {{1} \over {2}}. The crystal structure of YPI consists of one-dimensional columnar stacks of [{\rm YbPc} _{2} ^{2/3+}]
n
and of linear iodine chains [{\rm I} _{3} ^{-}]
n
. The modulation is commensurate since the period c
I of iodine chains [{\rm I} _{3} ^{-}]
n
in the [001] direction is equal to one-half of the period c of the [{\rm YbPc} _{2} ^{2/3+}]
n
stacks. In the crystal structure, each stack of [{\rm YbPc} _{2} ^{2/3+}]
n
may occur in two settings shifted by c/2 and each iodine chain in three settings shifted along [001] by one-third of the period c
I. The short-range order of iodine chains distributed over three settings results in a complicated pattern. Iodine chains of the same setting tend to form ribbons perpendicular to 〈100〉 and running along [001].
Thermodynamic environments in proteins: Fundamental determinants of fold specificity
Authors: Wrabl James O. , Larson Scott A. , Hilser Vincent J. 
Published: October 2002

AbstractTo investigate the relationship between an amino acid sequence and its corresponding protein fold, a database of thermodynamic stability information was assembled as a function of residue type from 81 nonhomologous proteins. This information was obtained using the COREX algorithm, which computes an ensemble‐based description of the native state of proteins. Dissection of the COREX stability constant into its fundamental energetic components resulted in 12 thermodynamic environments describing the tertiary architecture of protein folds. Because of the observation that residue types partitioned unequally between these environments, it was hypothesized that thermodynamic environments contained energetic information that connected sequence to fold. To test the significance of this hypothesis, the thermodynamic stability information was incorporated into a three‐dimensional–to–one‐dimensional scoring matrix, and simple fold recognition experiments were performed in a manner such that information about the fold target was never included in the scoring. For 60 out of 81 fold targets, the correct sequence for the target scored in the top 5% of 3858 decoy sequences, with Z‐scores ranging from 1.76 to 12.23. Furthermore, a scoring matrix assembled from the residues of 40 nonhomologous all‐α proteins was used to thread sequences against 12 nonhomologous all‐β protein targets. In 10 of 12 cases, sequences known to adopt the native all‐β structure scored in the top 5% of 3858 decoy sequences, with Z‐scores ranging from 1.99 to 7.94. These results indicate that energetic information encoded by thermodynamic environments represents a fundamental property of proteins that underlies classifications based on secondary structure.
Overcoming drug resistance in HIV‐1 chemotherapy: The binding thermodynamics of Amprenavir and TMC‐126 to wild‐type and drug‐resistant mutants of the HIV‐1 protease
Authors: Ohtaka Hiroyasu , Velázquez‐Campoy Adrian , Xie Dong , Freire Ernesto 
Published: October 2002

AbstractAmprenavir is one of six protease inhibitors presently approved for clinical use in the therapeutic treatment of AIDS. Biochemical and clinical studies have shown that, unlike other inhibitors, Amprenavir is severely affected by the protease mutation I50V, located in the flap region of the enzyme. TMC‐126 is a second‐generation inhibitor, chemically related to Amprenavir, with a reported extremely low susceptibility to existing resistant mutations including I50V. In this paper, we have studied the thermodynamic and molecular origin of the response of these two inhibitors to the I50V mutation and the double active‐site mutation V82F/I84V that affects all existing clinical inhibitors. Amprenavir binds to the wild‐type HIV‐1 protease with high affinity (5.0 × 109 M−1 or 200 pM) in a process equally favored by enthalpic and entropic contributions. The mutations I50V and V82F/I84V lower the binding affinity of Amprenavir by a factor of 147 and 104, respectively. TMC‐126, on the other hand, binds to the wild‐type protease with extremely high binding affinity (2.6 × 1011 M−1 or 3.9 pM) in a process in which enthalpic contributions overpower entropic contributions by almost a factor of 4. The mutations I50V and V82F/I84V lower the binding affinity of TMC‐126 by only a factor of 16 and 11, respectively, indicating that the binding affinity of TMC‐126 to the drug‐resistant mutants is still higher than the affinity of Amprenavir to the wild‐type protease. Analysis of the data for TMC‐126 and KNI‐764, another second‐generation inhibitor, indicates that their low susceptibility to mutations is caused by their ability to compensate for the loss of interactions with the mutated target by a more favorable entropy of binding.
Crystal structures and enzymatic properties of three formyltransferases from archaea: Environmental adaptation and evolutionary relationship
Authors: Mamat Björn , Roth Annette , Grimm Clemens , Ermler Ulrich , Tziatzios Christos , Schubert Dieter , Thauer Rudolf K. , Shima Seigo 
Published: October 2002

AbstractFormyltransferase catalyzes the reversible formation of formylmethanofuran from N5‐formyltetrahydromethanopterin and methanofuran, a reaction involved in the C1 metabolism of methanogenic and sulfate‐reducing archaea. The crystal structure of the homotetrameric enzyme from Methanopyrus kandleri (growth temperature optimum 98°C) has recently been solved at 1.65 Å resolution. We report here the crystal structures of the formyltransferase from Methanosarcina barkeri (growth temperature optimum 37°C) and from Archaeoglobus fulgidus (growth temperature optimum 83°C) at 1.9 Å and 2.0 Å resolution, respectively. Comparison of the structures of the three enzymes revealed very similar folds. The most striking difference found was the negative surface charge, which was −32 for the M. kandleri enzyme, only −8 for the M. barkeri enzyme, and −11 for the A. fulgidus enzyme. The hydrophobic surface fraction was 50% for the M. kandleri enzyme, 56% for the M. barkeri enzyme, and 57% for the A. fulgidus enzyme. These differences most likely reflect the adaptation of the enzyme to different cytoplasmic concentrations of potassium cyclic 2,3‐diphosphoglycerate, which are very high in M. kandleri (>1 M) and relatively low in M. barkeri and A. fulgidus. Formyltransferase is in a monomer/dimer/tetramer equilibrium that is dependent on the salt concentration. Only the dimers and tetramers are active, and only the tetramers are thermostable. The enzyme from M. kandleri is a tetramer, which is active and thermostable only at high concentrations of potassium phosphate (>1 M) or potassium cyclic 2,3‐diphosphoglycerate. Conversely, the enzyme from M. barkeri and A. fulgidus already showed these properties, activity and stability, at much lower concentrations of these strong salting‐out salts.