bluuebunny/crossref_metadata_2025_split huggingface dataset:
Plasma Membrane Intrinsic Proteins from Maize Cluster in Two Sequence Subgroups with Differential Aquaporin Activity
Authors: Chaumont François , Barrieu François , Jung Rudolf , Chrispeels Maarten J. 
Published: July 2002

Abstract
The transport of water through membranes is regulated in part by aquaporins or water channel proteins. These proteins are members of the larger family of major intrinsic proteins (MIPs). Plant aquaporins are categorized as either tonoplast intrinsic proteins (TIPs) or plasma membrane intrinsic proteins (PIPs). Sequence analysis shows that PIPs form several subclasses. We report on the characterization of three maize (Zea mays) PIPs belonging to the PIP1 and PIP2 subfamilies (ZmPIP1a, ZmPIP1b, and ZmPIP2a). The ZmPIP2a clone has normal aquaporin activity in Xenopus laevisoocytes. ZmPIP1a and ZmPIP1b have no activity, and a review of the literature shows that most PIP1 proteins identified in other plants have no or very low activity in oocytes. Arabidopsis PIP1 proteins are the only exception. Control experiments show that this lack of activity of maize PIP1 proteins is not caused by their failure to arrive at the plasma membrane of the oocytes. ZmPIP1b also does not appear to facilitate the transport of any of the small solutes tried (glycerol, choline, ethanol, urea, and amino acids). These results are discussed in relationship to the function and regulation of the PIP family of aquaporins.
Five Geranylgeranyl Diphosphate Synthases Expressed in Different Organs Are Localized into Three Subcellular Compartments in Arabidopsis
Authors: Okada Kazunori , Saito Takeshi , Nakagawa Tsuyoshi , Kawamukai Makoto , Kamiya Yuji 
Published: July 2002

AbstractGeranylgeranyl diphosphate (GGPP) is the precursor for the biosynthesis of gibberellins, carotenoids, chlorophylls, isoprenoid quinones, and geranylgeranylated proteins in plants. There is a small gene family for GGPP synthases encoding five isozymes and one related protein in Arabidopsis, and all homologs have a putative localization signal to translocate into specific subcellular compartments. Using a synthetic green fluorescent protein (sGFP), we studied the subcellular localization of these GGPP synthases. When these fusion proteins were expressed by the cauliflower mosaic virus 35S promoter in Arabidopsis, GGPS1-sGFP and GGPS3-sGFP proteins were translocated into the chloroplast, GGPS2-sGFP and GGPS4-sGFP proteins were localized in the endoplasmic reticulum, and the GGPS6-sGFP protein was localized in the mitochondria. Both GGPS1 and GGPS3 proteins synthesized in vitro were taken up into isolated intact pea chloroplasts and processed to the mature form. RNA-blot and promoter-β-glucuronidase (GUS) analysis showed that these GGPP synthases genes are organ-specifically expressed in Arabidopsis.GGR and GGPS1 were ubiquitously expressed, while GGPS2, GGPS3, andGGPS4 were expressed specifically in the flower, root, and flower, respectively. These results suggest that each GGPP synthase gene is expressed in different tissues during plant development and GGPP is synthesized by the organelles themselves rather than being transported into the organelles. Therefore, we predict there will be specific pathways of GGPP production in each organelle.
Deletion of the Nitrate Reductase N-Terminal Domain Still Allows Binding of 14-3-3 Proteins but Affects Their Inhibitory Properties
Authors: Provan Fiona , Aksland Liv-Margareth , Meyer Christian , Lillo Cathrine 
Published: July 2002

Abstract
Nitrate reductase (NR) is post-translationally regulated by phosphorylation and binding of 14-3-3 proteins. Deletion of 56 amino acids in the amino-terminal domain of NR was previously shown to impair this type of regulation in tobacco (Nicotiana plumbaginifolia) (L. Nussaume, M. Vincentez, C. Meyer, J.-P. Boutin, M. Caboche [1995] Plant Cell 7: 611–621), although both full-length NR and deleted NR (ΔNR) appeared to be phosphorylated in darkness (C. Lillo, S. Kazazaic, P. Ruoff, C. Meyer [1997] Plant Physiol 114: 1377–1383). We show here that in the presence of Mg2+ and phosphatase inhibitors, NR and endogenous 14-3-3 proteins copurify through affinity chromatography. Assay of NR activity and western blots showed that endogenous 14-3-3 proteins copurified with both NR and ΔNR. Electron transport in the heme-binding domain of ΔNR was inhibited by Mg2+/14-3-3, whereas this was not the case for NR. This may indicate a different way of binding for 14-3-3 in the ΔNR compared with NR. The ΔNR was more labile than NR, in vitro. Lability was ascribed to the molybdopterin binding domain, and apparently an important function of the 56 amino acids is stabilization of this domain.
Analysis of Gene Promoters for Two Tomato Polygalacturonases Expressed in Abscission Zones and the Stigma
Authors: Hong Seung-Beom , Sexton Roy , Tucker Mark L. 
Published: July 2002

Abstract
The tomato (Lycopersicon esculentum cv Ailsa Craig) polygalacturonase genes TAPG1(LYCes;Pga1;2) and TAPG4(LYCes;Pga1;5) are abundantly expressed in both abscission zones and the pistils of mature flowers. To further investigate the spatial and temporal expression patterns for these genes, the TAPG gene promoters were ligated to β-glucuronidase (GUS) reporter genes and transformed into tomato. GUS expression with both constructs was similar and entirely consistent with the expression patterns of the native gene transcripts. GUS activity was observed in the weakening abscission zones of the leaf petiole, flower and fruit pedicel, flower corolla, and fruit calyx. In leaf petiole and flower pedicel zones this activity was enhanced by ethylene and inhibited by indole-3-acetic acid. On induction of abscission with ethylene, GUS accumulation was much earlier in TAPG4:GUS than in TAPG1:GUS transformants. Moreover, TAPG4:GUS staining appeared to predominate in the vascular bundles relative to surrounding cortex cells whereas TAPG1:GUS was more evenly distributed across the separation layer. Like the native genes, GUS was also expressed in the stigma. Activity was not apparent in pistils until the flowers had opened and was confined to the stigma and style immediately proximal to it. A minimal promoter construct consisting of a 247-bp 5′-upstream element from TAPG1 was found to be sufficient to direct GUS expression in both abscission zones and the stigma.
Analysis of the Expression of CLA1, a Gene That Encodes the 1-Deoxyxylulose 5-Phosphate Synthase of the 2-C-Methyl-d-Erythritol-4-Phosphate Pathway in Arabidopsis
Authors: Estévez Juan M. , Cantero Araceli , Romero Cynthia , Kawaide Hiroshi , Jiménez Luis F. , Kuzuyama Tomohisa , Seto Haruo , Kamiya Yuji , León Patricia 
Published: July 2002

Abstract
The discovery of the 2-C-methyl-d-erythritol-4-phosphate pathway for the biosynthesis of isoprenoids raises the important question of the nature and regulation of the enzymes involved in this pathway.CLA1, a gene previously isolated from Arabidopsis, encodes the first enzyme of the 2-C-methyl-d-erythritol-4-phosphate pathway, 1-deoxy-d-xylulose-5-phosphate synthase. We demonstrate this enzyme activity by complementation of the cla1-1mutant phenotype and by direct enzymatic assays. Based on mRNA and protein expression patterns this enzyme is expressed mainly in developing photosynthetic and non-photosynthetic tissues. The β-glucuronidase expression pattern driven from theCLA1 gene regulatory region supports the northern and protein data while also showing that this gene has some level of expression in most tissues of the plant. A mutation in theCLA1 gene interferes with the normal development of chloroplasts and etioplasts, but does not seem to affect amyloplast structure. Microscopic analysis also shows a pleiotropic effect of theCLA1 gene mutation in mesophyll tissue formation.
Characterization of Arabidopsis Acid Phosphatase Promoter and Regulation of Acid Phosphatase Expression
Authors: Haran Shoshan , Logendra Sithes , Seskar Mirjana , Bratanova Margarita , Raskin Ilya 
Published: July 2002

AbstractThe expression and secretion of acid phosphatase (APase) was investigated in Indian mustard (Brassica juncea L. Czern.) plants using sensitive in vitro and activity gel assays. Phosphorus (P) starvation induced two APases in Indian mustard roots, only one of which was secreted. Northern-blot analysis indicated transcriptional regulation of APase expression. Polymerase chain reaction and Southern-blot analyses revealed two APase homologs in Indian mustard, whereas in Arabidopsis, only one APase homolog was detected. The Arabidopsis APase promoter region was cloned and fused to the β-glucuronidase (GUS) and green fluorescent protein (GFP) reporter genes. GUS expression was first evident in leaves of the P-starved Arabidopsis plants. In P-starved roots, the expression of GUS initiated in lateral root meristems followed by generalized expression throughout the root. GUS expression diminished with the addition of P to the medium. Expression of GFP in P-starved roots also initiated in the lateral root meristems and the recombinant GFP with the APase signal peptide was secreted by the roots into the medium. The APase promoter was specifically activated by low P levels. The removal of other essential elements or the addition of salicylic or jasmonic acids, known inducers of gene expression, did not activate the APase promoter. This novel APase promoter may be used as a plant-inducible gene expression system for the production of recombinant proteins and as a tool to study P metabolism in plants.
An Investigation of the Storage and Biosynthesis of Phenylpropenes in Sweet Basil
Authors: Gang David R. , Wang Jihong , Dudareva Natalia , Nam Kyoung Hee , Simon James E. , Lewinsohn Efraim , Pichersky Eran 
Published: July 2002

Abstract
Plants that contain high concentrations of the defense compounds of the phenylpropene class (eugenol, chavicol, and their derivatives) have been recognized since antiquity as important spices for human consumption (e.g. cloves) and have high economic value. Our understanding of the biosynthetic pathway that produces these compounds in the plant, however, has remained incomplete. Several lines of basil (Ocimum basilicum) produce volatile oils that contain essentially only one or two specific phenylpropene compounds. Like other members of the Lamiaceae, basil leaves possess on their surface two types of glandular trichomes, termed peltate and capitate glands. We demonstrate here that the volatile oil constituents eugenol and methylchavicol accumulate, respectively, in the peltate glands of basil lines SW (which produces essentially only eugenol) and EMX-1 (which produces essentially only methylchavicol). Assays for putative enzymes in the biosynthetic pathway leading to these phenylpropenes localized many of the corresponding enzyme activities almost exclusively to the peltate glands in leaves actively producing volatile oil. An analysis of an expressed sequence tag database from leaf peltate glands revealed that known genes for the phenylpropanoid pathway are expressed at very high levels in these structures, accounting for 13% of the total expressed sequence tags. An additional 14% of cDNAs encoded enzymes for the biosynthesis of S-adenosyl-methionine, an important substrate in the synthesis of many phenylpropenes. Thus, the peltate glands of basil appear to be highly specialized structures for the synthesis and storage of phenylpropenes, and serve as an excellent model system to study phenylpropene biosynthesis.
Cavitation Fatigue. Embolism and Refilling Cycles Can Weaken the Cavitation Resistance of Xylem
Authors: Hacke Uwe G. , Stiller Volker , Sperry John S. , Pittermann Jarmila , McCulloh Katherine A. 
Published: July 2002

Abstract
Although cavitation and refilling cycles could be common in plants, it is unknown whether these cycles weaken the cavitation resistance of xylem. Stem or petiole segments were tested for cavitation resistance before and after a controlled cavitation-refilling cycle. Cavitation was induced by centrifugation, air drying of shoots, or soil drought. Except for droughted plants, material was not significantly water stressed prior to collection. Cavitation resistance was determined from “vulnerability curves” showing the percentage loss of conductivity versus xylem pressure. Two responses were observed. “Resilient” xylem (Acer negundo and Alnus incanastems) showed no change in cavitation resistance after a cavitation-refilling cycle. In contrast, “weakened” xylem (Populus angustifolia, P. tremuloides, Helianthus annuusstems, and Aesculus hippocastanum petioles) showed considerable reduction in cavitation resistance. Weakening was observed whether cavitation was induced by centrifugation, air dehydration, or soil drought. Observations from H. annuus showed that weakening was proportional to the embolism induced by stress. Air injection experiments indicated that the weakened response was a result of an increase in the leakiness of the vascular system to air seeding. The increased air permeability in weakened xylem could result from rupture or loosening of the cellulosic mesh of interconduit pit membranes during the water stress and cavitation treatment.
Function and Dynamics of Auxin and Carbohydrates during Earlywood/Latewood Transition in Scots Pine
Authors: Uggla Claes , Magel Elisabeth , Moritz Thomas , Sundberg Björn 
Published: July 2002

Abstract
In temperate regions the annual pattern of wood development is characterized by the formation of radially narrow and thick walled latewood cells. This takes place at the later part of the growing season when cambial cell division declines. To gain new insight into the regulation of this process, micro-analytical techniques were used to visualize the distribution of indole-3-acetic acid (IAA), soluble carbohydrates, and activities of sucrose (Suc)-metabolizing enzymes across the cambial region tissues in Scots pine (Pinus sylvestris). The total amount of IAA in the cambial region did not change with latewood initiation. But its radial distribution pattern was altered, resulting in an increased concentration in the cambial meristem and its recent derivatives. Thus, initiation of latewood formation and cessation of cambial cell division is not a consequence of decreased IAA concentrations in dividing and expanding cells. Rather, IAA most likely has a role in defining the altered developmental pattern associated with latewood formation. Carbohydrates and enzyme activities showed distinctive radial distribution patterns. Suc peaked in the phloem and decreased sharply to low levels across the cambial zone, whereas fructose and glucose reached their highest levels in the maturing tracheids. Suc synthase was the dominating Suc cleaving enzyme with a peak in the secondary wall-forming tracheids and in the phloem. Soluble acid invertase peaked in dividing and expanding cells. Suc-phosphate synthase had its highest activities in the phloem. Activities of cell wall bound invertase were low. The absence of major seasonal variations indicates that carbohydrate availability is not a trigger for latewood initiation. However, steep concentration gradients of the sugars suggest a role for sugar signaling in vascular development.
AtCSLD3, A Cellulose Synthase-Like Gene Important for Root Hair Growth in Arabidopsis
Authors: Wang Xuan , Cnops Gerda , Vanderhaeghen Rudy , De Block Sabine , Van Montagu Marc , Van Lijsebettens Mieke 
Published: July 2002

Abstract
A member of the cellulose synthase-like (subfamily D) gene family of Arabidopsis, AtCSLD3, has been identified by T-DNA tagging. The analysis of the corresponding mutant,csld3-1, showed that the AtCSLD3 gene plays a role in root hair growth in plants. Root hairs grow in phases: First a bulge is formed and then the root hair elongates by polarized growth, the so-called “tip growth.” In the mutant, root hairs were initiated at the correct position and grew into a bulge, but their elongation was severely reduced. The tips of the csld3-1root hairs easily leaked cytoplasm, indicating that the tensile strength of the cell wall had changed at the site of the tip. Based on the mutant phenotype and the functional conservation between CSLD3 and the genuine cellulose synthase proteins, we hypothesized that the CSLD3 protein is essential for the synthesis of polymers for the fast-growing primary cell wall at the root hair tip. The distinct mutant phenotype and the ubiquitous expression pattern indicate that the CSLD3 gene product is only limiting at the zone of the root hair tip, suggesting particular physical properties of the cell wall at this specific site of the root hair cell.
Rationale of a quick adjustment method for crystal orientation in oscillation photography. Erratum
Authors: Suh I.-H. , Suh J.-M. , Ko T.-S. , Aoki K. , Yamazaki H. 
Published: July 2002

In the paper by Suh, Suh, Ko, Aoki & Yamazaki [J. Appl. Cryst. (1988). 21, 521–523], the penultimate sentence of the Concluding remarks section is in error. The correct sentence is Subtract the deviation in the bottom half from the deviation in the top half to give the correction for the vertical arc: if the result is + Δν
mm, rotate the vertical arc by Δv
° clockwise, and by Δν
° anticlockwise in the case of −Δν
mm.
The Application of Resonant Scattering Techniques toAb InitioStructure Solution from Powder Data using SrSO4as a Test Case
Authors: Burger K. , Cox D. , Papoular R. , Prandl W. 
Published: July 2002

The application of resonant (anomalous) scattering techniques toab initiostructure solution from powder data is demonstrated for the compound SrSO4. This material is orthorhombic, in space groupPnma(a = 8.359,b = 5.351,c = 6.869 Å,Z = 4), with 11 variable atomic positional parameters, and gives a fairly complex powder pattern with many overlapping peaks. Accurate high-resolution synchrotron X-ray powder diffraction data were obtained at three energies: 14, 225 and 5133 eV below the SrKedge. From combinations of two of the three data-sets, partial Patterson densities were derived and used to phase the 71 uniquely resolved reflections, allowing a complete solution of the rest of the structure. Maximum entropy methods were found to be far superior to standard Fourier methods in the reconstruction of the electron-density distribution. The techniques of data collection, analysis and phase determination required for resonant scattering experiments of this type are described in detail.
Structure and pseudosymmetry of cholesterol at 310 K
Authors: Hsu Leh-Yeh , Kampf Jeff W. , Nordman Christer E. 
Published: July 2002

The structure of cholesterol above the (304.8 K) phase transition, previously published in preliminary form [Hsu & Nordman (1983). Science, 220, 604–606], has been fully refined using augmented X-ray data. The crystals are triclinic, space group P1, with (reassigned) cell parameters a = 27.565 (10), b = 38.624 (16), c = 10.748 (4) Å, α = 93.49 (3), β = 90.90 (3), γ = 117.15 (3)°, and V = 10151 (7) Å3. The unit cell contains Z = 16 molecules, of which eight are related to the other eight by unusual twofold rotational pseudosymmetry. The structure is related to the room-temperature phase, with Z = 8, by a rearrangement of some of the molecules, and by a doubling of the a axis.
Crystallization and preliminary X-ray analysis of the catalytic subunit of the ATP-dependent arsenite pump encoded by the Escherichia coli plasmid R773
Authors: Zhou Tongqing , Rosen Barry P. , Gatti Domenico L. 
Published: July 2002

The arsenical resistance (ars) operon of the Escherichia coli plasmid R773 encodes a system for the active extrusion from cells of the toxic oxyanions arsenite (AsIIIO_{2}^{-}) and antimonite (SbIIIO_{2}^{-}) via an ATP-driven pump. The arsA and arsB genes of the operon encode the catalytic subunit (ATPase) and the membrane subunit of the pump, respectively. The arsC gene codes for a reductase that converts arsenate (AsVO_{4}^{3-}) to arsenite, thus extending bacterial resistance to the pentavalent state of arsenic. Crystals diffracting beyond 2.0 Å were obtained for the catalytic subunit of the pump (ArsA). These crystals belong to space group I222, with unit-cell parameters a ≃ 73, b ≃ 76, c ≃ 223 Å. A single molecule of ArsA, composed of two homologous halves, occupies the asymmetric unit of the I222 crystals with a predicted solvent content of 46%. Self-rotation function analysis suggests, however, that ArsA adopts a molecular packing corresponding to point group 422. One possible explanation of this result is that the two homologous halves of ArsA are related by a twofold axis of local symmetry and that the two halves of a `pseudo'-tetramer are related by a crystallographic twofold axis.
Crystallization and preliminary X-ray studies of metallothionein II from rabbit liver
Authors: An Yu , Li Genpei , Ru Binggen 
Published: July 2002

Metallothionein II (Mw
= 6.8 kDa), induced by cadmium and purified from rabbit liver, has been crystallized in space group P6222 or P6422. The unit-cell parameters were a = b = 113.4, c = 219.1 Å, α = β = 90.0, γ = 120.0° when crystallized from sodium citrate buffer and a = b = 113.4, c = 219.6 Å, α = β = 90.0, γ = 120.0° when crystallized from Tris–HCl buffer. There are 12 molecules per asymmetric unit and the solvent content is about 57%.
Production, crystallization and preliminary X-ray analysis of the human integrin \alpha_1 I domain
Authors: Salminen Tiina A. , Nymalm Yvonne , Kankare Jussi , Käpylä Jarmo , Heino Jyrki , Johnson Mark S. 
Published: July 2002

Integrin α1β1 is one of the main collagen receptors in many cell types. A fast large-scale production, purification and crystallization method for the integrin α1 I domain is reported here. The α1 I domain was crystallized using the vapour-diffusion method with a reservoir solution containing a mixture of PEG 4000, sodium acetate, glycerol and Tris–HCl buffer. The crystals beong to the C2 space group, with unit-cell parameters a = 74.5, b = 81.9, c = 37.3 Å, α = γ = 90.0, β = 90.8°. The crystals diffract to 2.0 Å and a 94.2% complete data set to 2.2 Å has been collected from a single crystal with an R
merge of 5.8%.
Expression, purification, crystallization and preliminary X-ray analysis of Escherichia coli argininosuccinate synthetase
Authors: Lemke Chris , Yeung Melissa , Howell P. Lynne 
Published: July 2002

A recombinant form of Escherichia coli argininosuccinate synthetase with a C-terminal polyhistidine affinity tag has been expressed, purified and subsequently crystallized using the hanging-drop vapour-diffusion technique. The crystals grow as large rectangular chunks with unit-cell dimensions a = 79.70, b = 105.84, c = 127.33 Å, α = β = γ = 90°. The crystals exhibit the symmetry of space group I222 and diffract to a minimum d-spacing of 1.6 Å at station X8C of the National Synchrotron Light Source, Brookhaven National Laboratory. On the basis of density calculations, one monomer of this homotetrameric protein is predicted per asymmetric unit (Matthews coefficient Vm
= 2.69 Å3 Da−1).
Crystallization and preliminary X-ray diffraction studies of human epidermal growth factor
Authors: Chai Ji-Jie , Li Ming , Huang Bing-Ren , Luo Yu , Luo Ming , Bi Ru-Chang , He Cun-Heng 
Published: July 2002

Human epidermal growth factor (hEGF), a 6.2 kDa protein of 53 amino acids with three internal disulfide bridges, has been crystallized by the hanging-drop method. hEGF crystallizes in space group P3121 (or P3221) using MgCl2 as precipitant, with unit-cell parameters a = b = 61.4, c = 87.0 Å. Another type of crystal, obtained using NaCl as precipitant, belongs to a tetragonal point group and has unit-cell dimensions a = b = 102.5, c = 166.6 Å. The trigonal crystals with the smaller unit cell diffract X-rays better and a native data set from a single crystal has been collected to 3.0 Å resolution.