bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effects of O2 on net photosynthesis at low temperature (5°C)
Authors: CORNIC GABRIEL , LOUASON GENEVIÈVE 
Published: April 2006

Abstract. It has been shown that atmospheric O2 can either depress or stimulate the rate of apparent photosynthesis of white mustard depending on the environmental conditions: CO2 concentration, light intensity and temperature. Stimulation by O2 was observed only under high photon fluence rate and at high CO2 concentrations. The critical CO2 concentration below which O2 was inhibiting and above which it was stimulating was dependent on the temperature of the assay: for plants grown at 12°C the critical CO2 concentration was 13.35 mmol at 5° C and 21.92 mmol at 10° C. Stimulation by O2 depended also on the growth temperature: for measurements at 26.31 mmol m−3 CO2, O2 was stimulating at temperatures less than 12°C for plants grown at 12°C and less than 19°C for plants grown at 27°C. The efficiency of the O2‐dependent stimulation of net photosynthesis was maximum at 9.21 mol m−3 O2 at 26.31 mmol m−3 CO2.Oxygen‐stimulation of net photosynthesis was detected in Nicotiana tabacum L. var Samsun, Lycopersicum esculentum L. and Chenopodium album L. At 5°C and under high photon fluence rate, O2 increased the carboxylation capacity of the photosynthetic apparatus of mustard and decreased its affinity for CO2. The O2 inhibition of the net CO2 uptake observed at low CO2 concentrations was the result of a decrease in the affinity for carbon dioxide. The nature of the mechanism which causes the stimulation of photosynthesis is discussed.
Accumulation and conversion of sugars by developing wheat grains. 4. Effects of phosphate and potassium ions in endosperm slices
Authors: RIJVEN A. H. G. C. , GIFFORD R. M. 
Published: April 2006

Abstract. Transverse slices through developing grains of Triticum aestivum cv. SUN 9E 16 d after anthesis were incubated in simple defined media with various radioactive labels. In some enzymic assays slices were pretreated with 2.5% Triton X‐100 or with 5% butanol to remove cellular membranes and endogenous substrates.Endogenous potassium leaked from endosperm slices into 30mol m−3 sucrose while sucrose was converted partly into starch. Exogenous alkali‐ions, except Li+, stimulated conversion of sucrose to insoluble matter, specifically to starch with K+. Starch synthetase activity of Triton‐pretreated slices was stimulated by K+ at both high and low substrate ADPG concentration, but was not affected by phosphate (25 mol m−3).Phosphate in the medium had no effect on incorporation of sucrose or glucose into alcohol‐insoluble material or starch in fresh slices (internal inorganic phosphate (P,) concentration was about 11 mol m−3). Three‐ to four‐fold contrasts in internal Pi level, achieved by prolonged preincubations in different media, did not show an inhibition of starch synthesis by Pi. However, phosphate (25mol m−3) inhibited starch synthesis, that was mediated by ADPG pyrophosphorylase in butanol‐pretreated endosperm slices by 15–18%.It is concluded that starch synthesis in wheat endosperm is not regulated directly by apoplastic Pi; level.
Phytochrome control mechanisms in leaf expansion ofPhaseolus vulgariscv. Limburg.
Authors: HOREMANS S. , VAN ONCKELEN H. A. , DE GREEF J. A. 
Published: April 2006

Abstract.The effectiveness of a red‐light pulse acting through phytochrome in inducing primary leaf expansion in 9‐d‐old etiolated bean (Phaseolus vulgarisL. ev. Limburg) seedlings is strongly increased by a continuous far‐red light (CFR) pretreatment. This increase in effectiveness of a red pulse is positively correlated with the time and the fluence rate of the CFR pretreatment. Escape from photoreversibility of this red pulse after the CFR pretreatment is extremely slow (more than 3 d). When a dark period is interposed between the end of the CFR pretreatment and the inductive red pulse the photoreversible part of the response to this pulse is highly dependent upon the photostationary state of phytochrome at the onset of the dark period.The results give strong evidence for the synergistic activity of two components of phytochrome action during leaf growth induction, one of them acting via a very stable Pfr fraction.
The fusicoccin‐stimulated phosphorylation of a 33 KDa polypeptide in cells of Acer pseudoplatanus as influenced by extracellular and intracellular pH
Authors: TOGNOLI L. , BASSO BARBARA 
Published: April 2006

Abstract In a previous study, it was shown that the fungal toxin fusicoccin (FC) is able to stimulate the in vivo phosphorylation of a 33 KDalton polypeptide (33 KP) independently of protein synthesis. Here we show that the stimulation by FC of both proton efflux and 33 KP phosphorylation are strongly enhanced when the external medium contains K+ or Na+, suggesting that the two phenomena are related. The stimulatory effect of FC is higher in unbuffered than in buffered media; moreover, in the absence of FC, 33 KP is more phosphorylated at an acidic than at a basic pH of the medium, suggesting that the effect of FC may depend, to a certain extent, on the acidification of the free space caused by FC‐promoted proton efflux.Treatments reported to alter the intracellular pH influence 33 KP phosphorylation even more strongly than the external pH does. The acidifying agents isobutyric acid and trimethylacetic acid decrease 33 KP phosphorylation, while the alkalinizing agents, ammonia and procaine, increase it. FC partially counteracts the inhibition by the weak acids, whereas the stimulatory effect of FC is not additive with that of the weak bases.The results indicate that 33 KP phosphorylation senses both the external and internal pH. The stimulatory effect of cytoplasm‐alkalinizing treatments, which mimics that of FC, agrees with the reported capacity of FC to cause cytoplasmic alkalinization, following activation of the plasmalemma proton pump.
A field portable system for the measurement of gas exchange of leaves under natural and controlled conditions: examples with field‐grown Eucalyptus pauciflora Sieb. ex Spreng. ssp. pauciflora, E. behriana F. Muell. and Pinus radiata R. Don.
Authors: KÜPPERS M. , SWAN A. G. , TOMPKINS D. , GABRIEL W. C. L. , KÜPPERS B. I. L. , LINDER S. 
Published: April 2006

Abstract A field portable system is described which measures the response of gas exchange of one leaf to changes in environmental parameters under controlled conditions, and which simultaneously measures the gas exchange of another leaf as the climatic parameters vary naturally. The system consists of two independently operating cuvettes. It enables detailed studies of photosynthesis and stomata/transpiration of leaves attached to the plant in their natural position. It provides control of temperature, humidity, CO2 and oxygen concentration (or, alternatively, of other gases) as well as of light. Infrared gas analyzers for CO2 and H2O are used which allow similar time constants for the measurement of the two gases.Examples of a diurnal course of gas exchange of a leaf in its natural exposition and of experiments with steady‐state responses of gas exchange are presented. In Eucalyptus pauciflora Sieb. ex Spreng. ssp. pauciflora, a set of response curves of CO, assimilation (A) to CO2, as measured at various leaf temperatures and light levels, shows carboxylation efficiency to be light saturated at the lower photon irradiances the lower the leaf temperature is. Carboxylation efficiency is maximal at 25°C. At ambient CO, partial pressure stomata open in a way that CO2 assimilation occurs at a rate found within the curvature region of the CO2 response function of A. The light‐independent CO2 compensation point as a function of temperature is presented.Applying a combined heat/low humidity pulse (15 or 60 min) on leaves of Eucalyptus behriana F. Muell. or Pinus radiata R. Don, respectively, leads to a lower level of intercellular carbon dioxide partial pressure (Ci) during the decline in A and leaf conductance to water vapour (g). A lower Ci level is maintained during recovery of A and g, A almost reaching the pre‐pulse level but not g. The existence of an after‐effect indicates that the response to the combined high temperature/low humidity pulse is a multi‐step process.
The effect of nutrients on adenine nucleotide levels and the adenylate energy charge ratio in Spartina alterniflora and Spartina patens
Authors: MENDELSSOHN I. A. , McKEE K. L. 
Published: April 2006

Abstract. The response of the adenylate energy charge (AEC) ratio and the adenine nucleotide pools to nutrients was studied in two perennial marsh plant species. Adenine nucleotide levels and the AEC ratio were measured in Spartina patens (Alton) Muhl. plants which were grown in the greenhouse at various nutrient levels as well as in Spartina alterniflora Loisel. transplants removed from the field but maintained in marsh soil amended with different nutrient supplements. In addition, adenine nucleotide concentrations were measured in both species in their natural environment and compared with that of the same species grown in the greenhouse with a complement of nutrients.The addition of nutrients stimulated an increase in the individual and total adenylate pools and the AEC ratio. Low nutrient levels resulted in extremely reduced adenylate pools. The AEC ratio was significantly affected in some instances, but did not decrease proportionately with the adenine nucleotide level and was typically maintained at values above 0.60. The adenine nucleotide concentrations measured in the leaves of both species were significantly higher in greenhouse‐grown plants compared to field plants, but the AEC ratios were not significantly different.Because the AEC ratio in plants can be significantly affected by nutrient level. AEC response in field investigations should be planned with attention to the potential effect of dissimilar nutrient levels among study sites.
Analysing partitioning in plants
Authors: LANG ALEXANDER , THORPE M. R. 
Published: April 2006

Abstract. Our understanding of the control of partitioning in plants and crops is confounded by unsatisfactory and incomplete description of the phenomenon. This paper attempts to improve upon this state of affairs by taking a fresh look at the concepts and the terms we use.While the continued usefulness in general discussion of the popular concepts of source, path and sink and of limitation is recognized, for analysing carbon flows we propose a separate, more practicable and higher level form of description based on a pool: process concept. This is similar to those used to describe the flows of other things in nature. In our analysis of competition between pools, the constant properties pool permeance and pool potential determine partitioning which is a function of the single variable plant potential. A simple phenomenological model embodying them is developed. Because our scheme is less demanding of experimental technique than some, its wide application seems feasible, extending even to the analysis of conventional crop growth measurements. The paper concludes by indicating briefly the sorts of physiological factors which could give rise to these phenomenological properties.
Prolonged chilling under moderate light: effect on photosynthetic activity measured with the photoacoustic method
Authors: D YAKIR  , RUDICH J. , BRAVDO B. A. , MALKIN S. 
Published: April 2006

Abstract Exposure of tomato plants to a mild chilling temperature and relatively low ambient photon flux density for an extended period (10°C and 400 μmol photons m−2 s−1 d and 5°C night for 6 d) resulted in a significant decrease in the variable chlorophyll fluorescence, the quantum yield of oxygen evolution and the amount of total absorbed energy stored in photochemical intermediates, but not in the chlorophyll concentration or in the activity of ribulose biphosphate carboxylase. These results indicate that photochemical processes involving PSII were affected, and might reflect photoinhibitory effects on the photosynthetic apparatus.Chilling treatment had relatively small influence on the maximal extent of the Emerson effect. This observation, together with the sharp decrease found in the quantum yield of oxygen evolution, could be reconciled with the above results only if some dependency between the two photosystems was assumed. On the basis of this interpretation, it was concluded that the strong Emerson effect after chilling still reflects the typical imbalance between PSI and PSII centres, even though populations of such unaffected pairs are smaller than in the untreated plants.The relatively new photoacoustic technique employed in this study is shown to be useful both as a diagnostic tool and as a means of investigating changes in photochemical activity in the study of environmental stress effects on photosynthesis. The results support the view that photoinhibition can play an important role in limiting photosynthetic activity, and therefore productivity, in chilling‐sensitive plants such as the tomato under the natural conditions that prevail during the winter in mediterranean climates.
Low‐molecular‐weight heparin (enoxaparin) as adjuvant therapy in the treatment of active ulcerative colitis: a randomized, controlled, comparative study
Authors: ZEZOS P. , PAPAIOANNOU G. , NIKOLAIDIS N. , PATSIAOURA K. , PAPAGEORGIOU A. , VASSILIADIS T. , GIOULEME O. , EVGENIDIS N. 
Published: April 2006

SummaryBackgroundHeparin could be beneficial to the treatment of active ulcerative colitis because of its anticoagulant, anti‐inflammatory and immunomodulatory properties.AimTo evaluate the tolerability, safety and efficacy of low‐molecular‐weight heparin as adjuvant therapy in patients with active ulcerative colitis.MethodsThirty‐four adult patients with active ulcerative colitis were consecutively included in a prospective, randomized, comparative study, and were treated for 12 weeks. Eighteen patients in the ‘standard therapy’ group were treated with aminosalicylates and weekly tapered corticosteroids. Sixteen patients in the ‘heparin therapy’ group were treated with standard therapy plus enoxaparin 100 Anti‐Xa IU/kg/day subcutaneously.ResultsSeventeen patients in the ‘standard therapy’ group and 15 patients in the ‘heparin therapy’ group completed the study. Tolerability and compliance to therapy were excellent and no withdrawals were noted because of complications. There was a significant improvement in the disease severity in both groups (P < 0.001), without any difference between them (P = not significant). Both treatment groups showed similar proportions of disease improvement (65% and 73%, respectively; P = not significant). There were no significant differences in inflammation (fibrinogen, ESR, CRP) and coagulation (thrombin–antithrombin complex, F1 + 2, D‐dimers) parameters during and at the end of the study between treatment groups.ConclusionAdjuvant administration of low‐molecular heparin in patients with active ulcerative colitis is safe and well tolerated, but no additive benefit over standard therapy for ulcerative colitis was noted.
Bioavailability and therapeutic activity of alicaforsen (ISIS 2302) administered as a rectal retention enema to subjects with active ulcerative colitis
Authors: MINER P. B. , GEARY R. S. , MATSON J. , CHUANG E. , XIA S. , BAKER B. F. , WEDEL M. K. 
Published: April 2006

SummaryBackgroundAlicaforsen is a phosphorothioate‐modified antisense oligodeoxynucleotide designed to sequence‐specifically reduce intercellular adhesion molecule 1 messenger RNA levels.AimsTo determine the systemic and local bioavailability of alicaforsen, and its activity when administered as a once daily enema in subjects with active ulcerative colitis.MethodsAn open‐label study was conducted to assess the relative absorption (local and systemic pharmacokinetics) and pharmacologic activity of alicaforsen enema in subjects with active ulcerative colitis. Fifteen subjects received nightly enemas of alicaforsen (240 mg) for a treatment period of 6 weeks. Alicaforsen concentrations in plasma and colonic tissue biopsies were determined. Disease activity index and multiple measurements including endoscopy were used to assess alicaforsen activity in these subjects.ResultsPlasma concentrations of parent alicaforsen represented < 0.6% mean bioavailability when compared with historical intravenous area under the plasma concentration–time curves. Concentrations of the intact oligonucleotide in mucosal colonic tissue biopsies were orders of magnitude higher than those observed in plasma. A 46% reduction in mean Disease Activity Index and 33% rate of remission as defined by complete mucosal healing were observed at the end of treatment.ConclusionThese data confirm that alicaforsen enema provides local treatment for a local disease with little meaningful systemic exposure.
The impact of low‐dose aspirin on endoscopic gastric and duodenal ulcer rates in users of a non‐selective non‐steroidal anti‐inflammatory drug or a cyclo‐oxygenase‐2‐selective inhibitor
Authors: GOLDSTEIN J. L. , LOWRY S. C. , LANZA F. L. , SCHWARTZ H. I. , DODGE W. E. 
Published: April 2006

SummaryBackgroundThe effect of low‐dose aspirin on endoscopic ulcer incidence in cyclo‐oxygenase‐2‐selective inhibitor or non‐selective non‐steroidal anti‐inflammatory drug users remains controversial.AimTo compare prospectively the incidence of endoscopic ulcers in healthy subjects receiving low‐dose aspirin plus celecoxib or naproxen.MethodsIn this double‐blind, placebo‐controlled, 1‐week study, subjects (50–75 years) were randomized to receive aspirin 325 mg o.d. plus either celecoxib 200 mg o.d., naproxen 500 mg b.d., or placebo. Baseline and end of study endoscopies were performed. The primary end point was incidence of one or more gastric and duodenal ulcers.ResultsA lower incidence of gastric and duodenal ulcers was seen in celecoxib/aspirin‐treated subjects (19%) vs. naproxen/aspirin (27%; RR: 0.63, 95% CI: 0.44–0.92). Both naproxen/aspirin and celecoxib/aspirin groups demonstrated a higher incidence of gastric and duodenal ulcers vs. placebo/aspirin (8%; RR: 3.7, 95% CI: 1.8–7.6 and RR: 2.6, 95% CI: 1.2–5.8, respectively).ConclusionsFewer endoscopic ulcers were observed in patients treated with celecoxib/aspirin vs. naproxen/aspirin. However, celecoxib/aspirin was associated with a significantly higher incidence of gastric and duodenal ulcers than aspirin alone. Further studies are required to determine the generalizability of these findings in the aspirin users and to determine the appropriate strategy to minimize risk in susceptible patients.
Review article: oesophageal spasm – diagnosis and management
Authors: TUTUIAN R. , CASTELL D. O. 
Published: April 2006

SummaryOesophageal spasm is a common empiric diagnosis clinically applied to patients with unexplained chest pain. In contrast it is an uncommon manometric abnormality found in patients presenting with chest pain and/or dysphagia and diagnosed by ≥20% simultaneous oesophageal contractions during standardized motility testing.Using Medline we searched for diagnostic criteria and treatment options for oesophageal spasm.While the aetiology of this condition is unclear, studies suggest the culprit being a defect in the nitric oxide pathway. Well‐known radiographic patterns have low sensitivities and specificities to identify intermittent simultaneous contractions.Recognizing that simultaneous contractions may result from gastro‐oesophageal reflux this diagnosis should be investigated or treated first. Studies have documented improvements with proton‐pump inhibitors, nitrates, calcium‐channel blockers and tricyclic antidepressants or serotonin reuptake inhibitors. Small case series reported benefits after botulinium toxin injections, dilatations and myotomies.Uncertainties persist regarding the optimal management of oesophageal spasm and recommendations are based on controlled studies with small numbers of patients or on case series. Acid suppression, muscle relaxants and visceral analgetics should be tried first. Botulinum toxin injections should be reserved for patients who do not respond. Pneumatic dilatations or myotomies represent rather heroic approaches for non‐responding patients.
Specific humoral immune responses in 12 cases of food sensitization to sesame seed
Authors: KOLOPP‐SARDA M. N. , MONERET‐VAUTRIN D. A. , GOBERT B. , KANNY G. , BRODSCHII M. , BENE M. C. , FAURE G. C. 
Published: April 2006

SummaryBackground
Hypersensitivity to sesume seeds is becoming increasingly frequent, probably owing to the larger use of this compound in international food.Objectives
This study investigated serum responses of 12 sesame sensitized patients (seven with food allergy, five with food sensitization), to a sesame protein extract, and attempted at identifying sesame major antigens.Methods
Sesame protein extracts were prepared from black, white and brown sesame seeds. Electrophoretic analysis showed similar protein patterns in the three extracts, and proper preservation of the proteins integrity. The brown sesame extract was used to set‐up an ELISA assay and measure serum levels of antisesame IgG, IgA, IgM and IgE in 12 samples from sesame‐sensitized individuals and six controls. It also allowed to perform western blot analyses in order to investigate the molecular weight of sesame proteins recognized by IgG, IgA and IgE.Results
Nineteen protein bands were observed upon polyacrylamide gel electrophoresis of the sesame protein extracts. Using this whole extract in ELISA, significant antisesame IgG. IgA and IgE‐responses were observed in the serum of sensitized individuals, different from the lower signals obtained with control samples. Western blot analysis demonstrated highly polymorphic IgG and IgA responses and a more restricted IgE response pattern, suggesting that two proteins, respectively. 14kDa and 25 kDa are mostly involved in sesame IgE‐dependent hypersensitivity, the 25 kDa band presenting several characteristics of a major allergen.Conclusions
This study reports novel information on the possible involvement of a 25 kDa sesame protein in IgE‐dependent hypersensitivity to sesame seeds.
Cloning and high level expression of Cynodon dactylon (Bermuda grass) pollen profilin (Cyn d 12) in Escherichia coli: purification and characterization of the allergen
Authors: ASTURIAS J. A. , ARILLA M. C. , GOMEZ‐BAYON N. , MARTINEZ J. , MARTINEZ A. , PALACIOS R. 
Published: April 2006

SummaryBackground
Profilin, an actin‐binding protein, was previously described as a panallergen which is involved in about 20% of Ihe crossreactivity found among pollen and food allergic patients. This allergen is usually under‐represented in natural extracts used for allergy diagnosis.Objectives
To obtain an immunologically active and soluble recombinant profilin from Cynodon dactylon pollen which could be used for diagnostic and therapy.Methods
Isolation of cDNA clones was performed by polymerase chain reaction amplification using degenerate primers. Expression in Eschehchia coli BL21 (DE3) was carried out using vector pKN172, and the expressed product was isolated by affinity chromatography on poly L‐proline‐Sepharose.Results
Four cDNA inserts coding for Cynodon dactylon (Bermuda grass) pollen profilin (Cyn d 12) were cloned and sequenced. Full‐length C. dactylon profilin gene was expressed in Escherichia coli as non fusion protein. Induced cells could produce high amounts of recombinant Cyn d 12, and after a single purification step on poly (L‐proline)‐Sepharose, up to 45 mg of pure allergen per litre culture could be obtained. The reactivity of recombinant Cyn d 12 with IgE antibodies present in sera from Bermuda grass‐allergic patients is comparable to that of the natural Bermuda grass allergen. Recombinant Bermuda grass pollen profilin was shown to share B‐epitopes with sunflower prolilin.Conclusions
Our results showed that this heterologous expression system and purification procedure are suitable for the production of large amounts of pure allergen which can be used for the characterization of allergenic epitopes recognized by T and B cells and finally for diagnostic and therapeutic purposes.