bluuebunny/crossref_metadata_2025_split huggingface dataset:
Growth and fruiting of tomato as influenced by elevated carbon dioxide and ozone
Authors: REINERT RICHARD A. , EASON GWEN , BARTON JEFFORY 
Published: March 2003

summary‘Tiny Tim’ tomato plants were exposed to five CO2 treatments (375 (ambient), 450, 525, 600 or 675 μmol mol−1) in combination with 03 (0 or 80 nmol mol−1. Biomass was evaluated following 3,5,7 and 13 wk exposure. Biomass following 13 wk exposure also included weekly harvests of mature tomato fruit beginning week 8. Carbon dioxide enrichment significantly enhanced total vegetative plant d. wt at each harvest, as well as cumulative yield of mature fruit, whereas O3 significantly suppressed total vegetative plant d. wt at each harvest and reduced total cumulative fruit yield. The magnitude of these changes varied with the development of tomato from early growth to mature fruit yield. Carbon dioxide enrichment reduced the detrimental effects of O3 on total vegetative plant d. wt of tomato following 3, 5, 7 and 13 wk exposure. Final mature fruit yield was 24% higher under enriched GO2 treatments than in ambient CO2. Ozone suppressed final yield by 31%, following exposure to 80 nmol mol−1 O2, when compared with exposure to charcoal‐filtered (CF) air. The impacts of both CO2 and O3 on yield were, however, dependent upon the presence or absence of the other gas. In the absence of O3, yields were very similar for the ambient and elevated CO2 treatments, but in the presence of O3, yields under ambient CO2 were greatly suppressed whereas yields under elevated CO3 were similar to those in the absence of O3. Thus, enriched CO2 ameliorated most of the suppressive effect of O3 on yield of mature fruit.
Colonization of tomato root by a non‐pathogenic strain of Fusarium oxysporum
Authors: OLIVAIN CHANTAL , ALABOUVETTE CLAUDE 
Published: March 2003

summaryA strain of non‐pathogenic Fusarium oxysporum Schlecht. emend, Snyd. & Hans. has been selected for its capacity to reduce the incidence of Fusarium wilt of tomato. Among the possible modes of action of this strain, competition with the pathogen for the colonization of the root surface and tissues has been proposed. In order to study the pattern of root colonization, young Lycopersicon etculentum Miller (tomato) plants grown in a nutrient solution were inoculated by a suspension of F. oxysporum microconidia and processed at time‐intervals for microscopic observations. The fungal strain was transformed with the Gus reporter gene to facilitate the observations. Within 24 h of inoculation the root surface was colonized by a dense network of hyphae, with the exception of the apex, which was colonized only after 48 h. A few hyphae were observed penetrating into the epidermis, leading to the internal colonization of the root cortex. This colonization was always discontinuous, since defence reactions of the plant limited the extension of the fungus. The barrier formed by thickenings and coilings of the cell walls and hypertrophied cells was most frequently observed in the external cortex and, sometimes, deeper in the internal cortex, close to the vessels which were never colonized. Typical defence reactions such as wall appositions, intercellular plugging and intracellular osmiophilic deposits, were frequently observed. This is the first report, based on microscopic observations, of the capacity of a non‐pathogenic strain of F. oxysporum to colonize roots of tomato.
Changes in root hydraulic conductance (KR) of Olea oleaster seedlings following drought stress and irrigation
Authors: LO GULLO MARIA A. , NARDINI ANDREA , SALLEO SEBASTIANO , TYREE MELVIN T. 
Published: March 2003

Quasi‐steady‐state measurements of root hydraulic conductance (KR) of Olea oleaster Hoffmgg. et Link potted seedlings were performed using a pressure chamber with the aim of: (a) measuring the impact of different water‐stress levels on a KR; (b) measuring the kinetics of KR recovery several days after soil rewetting; (c) relating changes in KR to changes in root anatomy and morphology. Increasing water‐stress was applied in terms of ratio of leaf water potential (ΨL) measured at midday to that at zero turgor (ΨTLP), i.e. ΨL/ΨTLP=0·5, 1·0, 1·2, 1·6; KR was measured initially and at 24, 48, 72, 96 h after irrigation.Values of KR in seedlings stressed to ΨL/ΨTLP=1·2 increased for 48 h after irrigation from 0·23 to 0·97×10−5 kg s−1 m−2 MPa−1 i.e. from 16% to 66% of that measured in unstressed seedlings. A marked shift of the x‐axis intercept of the straight line relating flow to pressure (zero flow at non‐zero pressure) was recorded initially after irrigation and persisted up to 48 h. Recovery of KR occurred within 24 h after irrigation in seedlings at ΨL/ΨTLP=0·5 and 48 h later in those at ΨL/ΨTLP=1·0.Severe drought stress (ΨL/ΨTLP=1·6) caused anatomical changes to roots which formed a two‐layered exodermis with thicker suberized walls and a three‐ to four‐layered endodermis with completely suberized tangential walls. Recovery of KR in these roots required resumed growth of root tips and emergence of new lateral roots.
Natural 13C and 15N abundance of field‐collected fungi and their ecological implications
Authors: KOHZU A. , YOSHIOKA T. , ANDO T. , TAKAHASHI M. , KOBA K. , WADA E. 
Published: March 2003

The natural abundance of 13C and 15N was measured in basidiocarps of at least 115 species in 88 genera of ectomycorrhizal, wood‐decomposing and litter‐decomposing fungi from Japan and Malaysia. The natural abundance of 13C and 15N was also measured in leaves, litter, soil and wood from three different sites. 15N and 13C were enriched in ectomycorrhizal and wood‐decomposing fungi, respectively, relative to their substrates. Ectomycorrhizal and wood‐decomposing fungi could be distinguished on the basis of their δ13C and δ15N signatures. Although there was high variability in the isotopic composition of fungi, the following isotope‐ enrichment factors (ε, mean±SD) of the fungi relative to substrates were observed:ε ectomycorrhizal fungi/litter = 6.1±0.4‰15Nε ectomycorrhizal fungi/wood = 1.4±0.8‰13Cε wood‐decomposing fungi/wood = −0.6±0.7‰15Nε wood‐decomposing fungi/wood = 3.5±0.9‰13CThe basis of isotope fractionation in C metabolism from wood to wood‐decomposing fungus is discussed.
Modelling a spring wheat crop under elevated CO2 and drought
Authors: Grossman‐Clarke S. , Pinter P. J. , Kartschall T. , Kimball B. A. , Hunsaker D. J. , Wall G. W. , Garcia R. L. , LaMorte R. L. 
Published: March 2003

Summary

The simulation model DEMETER was used here to investigate which mechanisms led to a larger CO2 effect on biomass production and yield of a spring wheat crop under drought compared with unlimited water supply.
Field data of the free‐air CO2 enrichment (FACE) wheat experiments in Arizona (1993–94) were used to test the model. The influence of a particular mechanism leading to a higher CO2 effect under drought was investigated by eliminating the influence of the other causes on the simulation results on selected days during the growing seasons.
A larger CO2 effect under drought was caused in the model by the lower potential transpiration rate, higher root biomass and the nonlinear functional dependence of net assimilation rate on leaf internal CO2 concentration. The contribution of the different mechanisms changed in significance during the growing season depending on the degree of soil water limitation. The model successfully described the qualitative and quantitative behaviour of the crop under elevated CO2.
A well‐tested simulation model can be a useful tool in understanding the complex interactions underlying observed ecosystem responses to stress under elevated CO2.
Immunocytochemical location of the (1→3) (1→4)‐β‐glucan lichenin in the lichen‐forming ascomycete Cetraria islandica (Icelandic moss)1
Authors: Honegger Rosmarie , Haisch Annette 
Published: March 2003

Summary

Thalli of Cetraria islandica (Icelandic moss) and Evernia prunastri (oak moss) contain considerable amounts of the linear (1→3), (1→4)‐β‐glucan lichenin (lichenan), which different proportions of linkage groups in either species.
The immunocytochemical location of lichenan within the thallus is reported using a monoclonal antibody (barley anti‐(1→3), (1→4)‐β‐glucan antibody) and low‐temperature scanning electron microscopy (LTSEM) techniques.
The antibody labelled ultrathin sections of C. islandica, but not of E. prunastri. In C. islandica, lichenin was located in the extracellular matrix of the peripheral cortex and in a thick outer wall layer of medullary hyphae. LTSEM of fully hydrated and desiccated thalli of C. islandica showed that both the cortical extracellular matrix and the outer wall layer of medullary hyphae shrink dramatically during drought stress, indicating that these are major sites of water storage. A mycobiont‐derived, hydrophilic wall surface layer prevents the thallus interior from becoming water‐logged at full hydration.
The LTSEM observations and immunocytochemical data strongly suggest that lichenin is a structural compound, rather than a storage product, with important functions in thallus water relations.
Are ectomycorrhizas more abundant than arbuscular mycorrhizas in tropical heath forests?
Authors: Moyersoen B. , Becker P. , Alexander I. J. 
Published: March 2003

Summary

Tropical heath forests have accumulations of slowly decomposing organic matter at the soil surface. To test the hypothesis that ectomycorrhizas are more abundant than arbuscular mycorrhizas under such conditions, we compared the abundance of ectomycorrhizal (EcM) tree species, and the relative proportions of EcM and arbuscular mycorrhizal (AM) roots, in heath forest and lowland rain forest.
The mycorrhizal status of trees in two heath forest and two lowland (mixed dipterocarp) forest plots in Brunei Darussalam was determined by literature and field survey. Fine‐root density, proportion of EcM roots, and fractional colonization of EcM and AM roots were measured in monoliths from organic and mineral soil.
There was no difference in the relative basal area abundance (10–41%) of EcM trees, the proportion of EcM roots in monoliths (8–46%), or fractional colonization (90%) of EcM roots, between the two forest types. However, fractional colonization of AM roots was higher (54%) in heath forest than in mixed dipterocarp forest (27%).
Our data do not support the hypotheses that ectomycorrhizas are more abundant in, or determine the floristic composition of, tropical heath forests.
Estimating age‐dependent costs and benefits of roots with contrasting life span: comparing apples and oranges
Authors: Bouma Tjeerd J. , Yanai Ruth D. , Elkin Adrienne D. , Hartmond Ulrich , Flores‐Alva Dora E. , Eissenstat David M. 
Published: March 2003

Summary

The relation between root age and root function is poorly understood, despite its importance to root longevity.
The effect of root age on respiration rates and 32P‐uptake kinetics was determined for roots excavated from mature apple and citrus trees (median root life spans of 30 vs 300 d). To evaluate whether root longevity maximizes the efficiency of nutrient capture, daily and lifetime efficiencies were calculated by dividing simulated P‐uptake benefits (solute transport model) by age‐specific respiration costs.
We found that: respiration rates and P uptake capacity change with root age in a species‐specific way; and soil characteristics that determine the rate of nutrient depletion in the rhizosphere are as important as changes in root physiology in determining the age at which a root reaches its maximum efficiency.
Further testing of the efficiency of nutrient capture as a predictor of root life span requires measurement of both soil properties and age‐specific physiology of roots including their mycorrhizal fungi.
Dual requirement of the LjSym4 gene for mycorrhizal development in epidermal and cortical cells of Lotus japonicus roots
Authors: Novero Mara , Faccio Antonella , Genre Andrea , Stougaard Jens , Webb K. Judith , Mulder Lonneke , Parniske Martin , Bonfante Paola 
Published: March 2003

Summary• The LjSym4 mutation leads to Lotus japonicus plants that are defective in arbuscular mycorrhiza (AM) development.• Two alleles of LjSym4 with different phenotypic strength are compared here. The development of AM was assessed by considering five parameters related to fungal structures present in root segments from wild‐type and mutant plants. The distribution of intercellular hyphae was determined using semithin sections from resin‐embedded roots. Cellular interactions were investigated ultrastructurally, whereas cell wall components from the host plant were identified using immunogold labeling.• In roots of Ljsym4‐1 mutant, fungal hyphae were mostly restricted to the intercellular spaces of the cortex, indicating a block to infection by mutant cortical cells, which resulted in a very low number of arbuscules.• This observation suggests the presence of an additional, genetically defined ‘checkpoint’ for mycorrhizal development, located at the wall of cortical cells. The LjSym4 gene is therefore required for infection of both epidermal and cortical cells by AM fungi.
Developmentally regulated conversion of surface‐exposed chitin to chitosan in cell walls of plant pathogenic fungi
Authors: El Gueddari Nour Eddine , Rauchhaus Una , Moerschbacher Bruno M. , Deising Holger B. 
Published: March 2003

Summary

Conversion of surface‐exposed chitin to chitosan in cell walls of in vitro
‐ and
in vivo
‐differentiated infection structures of two rust fungi, the wheat stem rust fungus
Puccinia graminis
f. sp.
tritici
and the broad bean rust fungus
Uromyces fabae
, and of the causal agent of maize anthracnose,
Colletotrichum graminicola , were studied.
Epi‐fluorescence microscopy with the fluorescence‐labeled lectin wheat germ agglutinin (WGA) revealed that surfaces of infection structures formed on the plant cuticle expose chitin, whereas surfaces of structures formed after invading the host do not.
To identify chitin modification by de‐ N
‐acetylation, we raised polyclonal antibodies specifically recognizing de‐
N ‐acetylated chitosan. These antibodies labeled only those infection structures that differentiate inside the plant, indicating that chitosan is exposed on cell wall surfaces post penetration.
Surface modification of the fungal cell walls by chitin de‐ N ‐acetylation is discussed as a fungal strategy to protect cell walls of pathogenic hyphae from enzymatic hydrolysis by host chitinases, and to avoid generation of an auto‐catalytic defense response system in the invaded host tissue.
Investigating indices to explain the impacts of ozone on the biomass of white clover (Trifolium repens L. cv. Regal) at inland and coastal sites in Spain
Authors: Bermejo V. , Gimeno B. S. , Granados I. , Santamaría J. , Irigoyen J. J. , Bermejo R. , Porcuna J. L. , Mills G. 
Published: March 2003

Summary

Ozone (O 3
) phytotoxicity is driven by the concentrations the plants are exposed to, and also by meteorological and physiological variables. Thus, O
3
uptake might be a better indicator of the phytotoxicity of this pollutant than O
3 exposure.
An ozone biomonitoring system based on the biomass ratio between an ozone‐resistant (NC‐R) and an ozone‐sensitive (NC‐S) biotype of white clover ( Trifolium repens
cv. Regal) has been tested for 4 yr at four Spanish sites experiencing wide differences in their climatic and ozone exposure profiles. A complementary experiment was also carried out in open‐top chambers exposing plants of both biotypes to three O
3
treatments. Ozone exposure, air temperature, relative humidity and leaf stomatal conductance to water vapour were measured during the life span of both clover clones. These measurements enabled the total O
3
accumulated dose (CUMFO
3 ) for each biotype to be calculated.
The biomass ratio of both clones was best correlated with indices based on O 3
uptake, rather than with indices related to O
3
exposure. In fact, the best performance of the system was achieved when O
3
uptake > 40 nl l
−l
(CUMFO
3 40) was considered.
The results support the need to relate O 3
phytotoxicity to actual plant O
3 uptake.
Neurotrophin‐3 mediates the autocrine survival of the catecholaminergic CAD CNS neuronal cell line
Authors: Horton Cheryl D. , Qi Yanping , Chikaraishi Dona , Wang James K. T. 
Published: March 2003

The mechanisms for neuronal survival in the CNS are not well understood, but are likely to be complex due to possible autocrine and redundant neurotrophic support. Most studies have focused on the nerve growth factor (NGF)/TrkA pathway in peripheral neurons, and little is known regarding the other neurotrophins, particularly neurotrophin‐3 (NT3)/TrkC. Progress has also been hampered by the paucity of homogenous and accessible CNS neuronal experimental models. We now report that the novel catecholaminergic CNS cell line, CAD, is capable of autocrine survival mediated by NT3. The CAD cell is of CNS neuronal origin and can survive and morphologically differentiate in the absence of exogenously provided trophic factors. However, neutralizing reagents against NT3 (the neutralizing TrkC‐IgG fusion protein and anti‐NT3 antibodies), but not those that block the other neurotrophins, inhibited survival of differentiating CAD cells. Moreover, Trk phosphorylation was detected in CAD cells and its inhibition by K252a was correlated with K252a‐induced apoptosis. Finally, endogenous NT3 was detectable in CAD cell extracts by a specific ELISA assay. Thus, CAD cells possess an autocrine survival capability mediated by NT3, and may provide a valuable model system for studying the signaling pathways that mediate the actions of this little understood neurotrophin.
Clozapine increases apolipoprotein D expression in rodent brain: towards a mechanism for neuroleptic pharmacotherapy
Authors: Thomas Elizabeth A. , Danielson Patria E. , Nelson P. Austin , Pribyl Thomas M. , Hilbush Brian S. , Hasel Karl W. , Sutcliffe J. Gregor 
Published: March 2003

In contrast to typical neuroleptic drugs, which have high affinities for dopamine D2 receptors, clozapine binds to multiple neurotransmitter receptors. The mechanisms responsible for its superior clinical efficacy over typical neuroleptics remain unknown. Using an automated genomics approach, total gene expression analysis (TOGA), we found an approximately threefold increase in the accumulation of the mRNA encoding apolipoprotein D (apoD) in mouse striatum in response to chronic treatment with clozapine. While in control animals, apoD is expressed predominantly in astrocytes, in situ hybridization and immunohistochemical studies indicated a substantial increase in apoD expression in neurons of the striatum, globus pallidus and thalamus after 2 weeks of clozapine treatment. Clozapine‐induced increases in apoD expression were also observed in some white matter regions. These results suggest that apoD is a mediator in the mechanisms of clozapine and thus that deficiencies in aspects of lipid metabolism may be responsible for psychoses.
Expression of Rho‐family GTPases (Rac, cdc42, RhoA) and their association with p‐21 activated kinase in adult rat peripheral nerve
Authors: Terashima Tomoya , Yasuda Hitoshi , Terada Masahiko , Kogawa Shuro , Maeda Kengo , Haneda Masakazu , Kashiwagi Atsunori , Kikkawa Ryuichi 
Published: March 2003

To clarify the presence of the Rho family of small GTPases p21‐activated kinase (pak) signaling pathway in the PNS, we have examined their expression, the association between the small GTPases and pak and the pak kinase activity in the PNS using immunoblot analysis, immunohistochemistry, co‐immunoprecipitation study, and in vitro kinase assay. Immunoblot analysis showed the expression of Rac, cdc42, RhoA and pak in the dorsal root ganglion (DRG) and sciatic nerve. The localization of these proteins in the DRG neurons and axons and Schwann cells of the sciatic nerve was confirmed by immunohistochemistry. Co‐immunoprecipitation studies indicated the in vivo associations of pak with Rac and cdc42, but not with RhoA, in both the DRG and sciatic nerve. The autophosphorylation of pak and phosphorylation of histone H4 by pak were also found in the DRG and sciatic nerve as well as in the CNS. These results suggest that the Rac/cdc42‐pak signaling pathway exists and functions in the PNS and may mediate some intracellular signals.
Bax κ, a novel Bax splice variant from ischemic rat brain lacking an ART domain, promotes neuronal cell death
Authors: Jin Kun Lin , Graham Steven H. , Mao Xiao Ou , He Xiangjun , Nagayama Tetsuya , Simon Roger P. , Greenberg David A. 
Published: March 2003

Bax is a pro‐apoptotic Bcl‐2 family protein that regulates programmed cell death through homodimerization and through heterodimerization with Bcl‐2. Bax α is encoded by six exons and undergoes alternative splicing. Bax κ, a splice variant of Bax with conserved BH1, BH2 and BH3 binding domains and a C‐terminal transmembrane domain (TM), but with an extra 446‐bp insert between exons 1 and 2 leading to loss of an N‐terminal ART domain, was identified from an ischemic rat brain cDNA library. Expression of Bax κ mRNA and protein was up‐regulated in hippocampus after cerebral ischemic injury. The increased Bax κ mRNA was distributed mainly in selectively vulnerable hippocampal CA1 neurons that are destined to die after global ischemia. Overexpression of Bax κ protein in HN33 mouse hippocampal neuronal cells induced cell death, which was partially abrogated by co‐overexpression of Bcl‐2. Moreover, co‐overexpression of Bax κ and Bax α increased HN33 cell death. The results suggest that the Bax κ may have a role in ischemic neuronal death.
Gene expression analysis in N‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine mice model of Parkinson's disease using cDNA microarray: effect of R‐apomorphine
Authors: Grünblatt Edna , Mandel Silvia , Maor Gila , Youdim Moussa B. H. 
Published: March 2003

To establish the possible roles of oxidative stress, inflammatory processes and other unknown mechanisms in neurodegeneration, we investigated brain gene alterations in N‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine (MPTP) mice model of Parkinson's disease using Atlas mouse cDNA expression array membrane. The expression of 51 different genes involved in oxidative stress, inflammation, glutamate and neurotrophic factors pathways as well as in still undefined processes, such as cell cycle regulators and signal transduction molecules, was differentially affected by the treatment. The present study indicates the involvement of an additional cascade of events that might act in parallel to oxidative stress and inflammation to converge eventually into a common pathway leading to neurodegeneration. The attenuation of these gene changes by R‐apomorphine, an iron chelator‐radical scavenger drug, supports our previous findings in vivo where R‐apomorphine was neuroprotective.