bluuebunny/crossref_metadata_2025_split huggingface dataset:
Growth velocity during the first postnatal week of life is linked to a spurt of IGF‐I effect
Authors: Skalkidou A. , Petridou E. , Papathoma E. , Salvanos H. , Trichopoulos D. 
Published: December 2004

SummaryThere is adequate evidence that growth during the perinatal period is linked to the risk of several adult onset diseases, and recent findings indicate that the insulin‐like growth factor (IGF) system is involved in prenatal growth, as reflected in birthweight. However, whether major components of the IGF system are involved in the immediate post‐natal growth has not been studied. Maternal questionnaires were completed, and laboratory measurements of several variables, including IGF‐I, IGF‐II and IGF‐binding protein‐3 (IGFBP‐3), were made for a total of 331 apparently healthy full‐term newborns, from whom routine blood samples were taken during the first 5 days of their life. Birthweight and weight at the time of bleeding were among the recorded variables, and the difference divided by the age in days of the newborn was considered as reflecting immediate postnatal growth velocity.Immediate postnatal growth velocity was strongly positively associated with IGF‐I. The squared adjusted correlation coefficient was 0.29 when IGF‐I was incorporated in the model predicting postnatal growth velocity but was only 0.08 when IGF‐I was excluded. In contrast, IGF‐II and IGFBP‐3 had no effect on postnatal growth velocity. It thus appears that IGF‐I underlies growth during the immediate postnatal period. To the extent that perinatal growth may affect adult onset diseases, the findings of this study suggest that the action of IGF‐I during the immediate postnatal period may represent a process of major importance.
Vaccination against Fasciola hepatica infection using a Schistosoma mansoni defined recombinant antigen, Sm14
Authors: Almeida Marília S. , Torloni Humberto , Lee‐Ho Paulo , Vilar Monica M. , Thaumaturgo Nilton , Simpson Andrew J. G. , Tendler Miriam 
Published: December 2004

SUMMARYFasciola hepatica is the causative agent of fasciolosis in many areas in America, Europe, Africa, Asia and Australia. There is an urgent need for improved methods to control the parasite's transmission. We describe the use of an experimental vaccine based on a recombinant antigen cloned from another parasite, Schistosoma mansoni (Sm14), that induces high levels of cross protection in mice against both S. mansoni and F. hepatica. Sheep and mice vaccinated with Sm14 were significantly protected against challenge infection with metacercariae of Fasciola hepatica and were completely free of the histopathological hepatic damage related to liver fluke infection. The vaccine will provide a valuable new tool to aid in transmission control of this economically important disease.
Nickel and zinc hyperaccumulation by Alyssum murale and Thlaspi caerulescens (Brassicaceae) do not enhance survival and whole‐plant growth under drought stress
Authors: WHITING S. N. , NEUMANN P. M. , BAKER A. J. M. 
Published: December 2004

ABSTRACTNickel and Zn hyperaccumulation by Alyssum murale and Thlaspi caerulescens bear substantial energetic costs and should confer benefits to the plant. This research determined whether metal hyperaccumulation can increase osmotic adjustment and resistance to water stress (drought). Alyssum murale and Thlaspi caerulescens treated with low or high concentrations of Ni or Zn were exposed to moderate (−0·4 MPa) and severe (−1·0 MPa) water stresses using aqueous polyethylene glycol. In the absence of metals both water deficits inhibited shoot growth. Nickel and Zn hyperaccumulation did not ameliorate growth inhibition by either level of water stress. The water stress did not induce major changes in shoot metal concentrations of these constitutive hyperaccumulators. Moreover, metal hyperaccumulation had minimal effects on the osmolality of leaf‐sap extracts, relative water content of the shoots, or rate of evapotranspiration. It is concluded that Ni or Zn hyperaccumulation does not augment whole‐plant capacity for drought resistance in A. murale and T. caerulescens.
Ultrasound acoustic emissions from freezing xylem*
Authors: KIKUTA S. B. , RICHTER H. 
Published: December 2004

ABSTRACTRachides of Juglans regia L. (Juglandaceae) and one‐year‐old twigs of Evonymus latifolia (L.) Mill. (Celastraceae) were cooled in air to −25 °C, with an ultrasound detector attached to the xylem where peripheral tissues had been peeled off. Ultrasound acoustic emissions started between −4·5 and −14·3 °C, as measured with a thermocouple inserted into the xylem. The number of emissions was significantly lower from saturated plant parts than from those frozen at field water potentials. Bench‐drying of saturated samples produced significantly less signals than the freezing protocols. These findings are in accordance with the hypothesis that freezing of xylem under tension induces cavitation events. They corroborate earlier work which tried to provide a logical explanation for the seemingly paradoxical cryo‐scanning electron microscope observations of changing vessel contents during a daycourse in the field.
Photosynthetic limitations in olive cultivars with different sensitivity to salt stress
Authors: LORETO F. , CENTRITTO M. , CHARTZOULAKIS K. 
Published: December 2004

ABSTRACTOlive (Olea europea L) is one of the most valuable and widespread fruit trees in the Mediterranean area. To breed olive for resistance to salinity, an environmental constraint typical of the Mediterranean, is an important goal. The photosynthetic limitations associated with salt stress caused by irrigation with saline (200 mm) water were assessed with simultaneous gas‐exchange and fluorescence field measurements in six olive cultivars. Cultivars were found to possess inherently different photosynthesis when non‐stressed. When exposed to salt stress, cultivars with inherently high photosynthesis showed the highest photosynthetic reductions. There was no relationship between salt accumulation and photosynthesis reduction in either young or old leaves. Thus photosynthetic sensitivity to salt did not depend on salt exclusion or compartmentalization in the old leaves of the olive cultivars investigated. Salt reduced the photochemical efficiency, but this reduction was also not associated with photosynthesis reduction. Salt caused a reduction of stomatal and mesophyll conductance, especially in cultivars with inherently high photosynthesis. Mesophyll conductance was generally strongly associated with photosynthesis, but not in salt‐stressed leaves with a mesophyll conductance higher than 50 mmol m−2 s−1. The combined reduction of stomatal and mesophyll conductances in salt‐stressed leaves increased the CO2 draw‐down between ambient air and the chloroplasts. The CO2 draw‐down was strongly associated with photosynthesis reduction of salt‐stressed leaves but also with the variable photosynthesis of controls. The relationship between photosynthesis and CO2 draw‐down remained unchanged in most of the cultivars, suggesting no or small changes in Rubisco activity of salt‐stressed leaves. The present results indicate that the low chloroplast CO2 concentration set by both low stomatal and mesophyll conductances were the main limitations of photosynthesis in salt‐stressed olive as well as in cultivars with inherently low photosynthesis. It is consequently suggested that, independently of the apparent sensitivity of photosynthesis to salt, this effect may be relieved if conductances to CO2 diffusion are restored.
The water‐filled versus air‐filled status of vessels cut open in air: the ‘Scholander assumption’ revisited
Authors: TYREE M. T. , COCHARD H. , CRUIZIAT P. 
Published: December 2004

ABSTRACTWhen petioles of transpiring leaves are cut in the air, according to the ‘Scholander assumption’, the vessels cut open should fill with air as the water is drained away by continued transpiration. The distribution of air‐filled vessels versus distance from the cut surface should match the distribution of lengths of ‘open vessels’, i.e. vessels cut open when the leaf is excised. Three different methods were used to estimate the length distribution of open vessels and compared it to the observed distribution of embolisms by the cryo‐scanning electron microscope (SEM) method. In the cryo‐SEM method, petioles are frozen in liquid nitrogen soon after the petiole is cut. The petioles are then cut at different distances from the original cut surface while frozen and examined in a cryo‐SEM facility, where it is easy to distinguish vessels filled with air from those filled with ice. In petioles of Acer platanoides and Juglans regia, the distribution of embolized vessels agrees with expectations. This is in contrast to a previous study on sunflower where cryo‐SEM results did not agree with expectations. The reason for this disagreement requires further study for a full elucidation.
Needle cytokinin content as a sensitive bioindicator of N pollution in Sitka spruce
Authors: COLLIER M. D. , SHEPPARD L. J. , CROSSLEY A. , HANKE D. E. 
Published: December 2004

ABSTRACTPrevious work has shown that conifers growing on sites exposed to aerial pollution exhibit a different pattern of vegetative development in comparison with those on unpolluted sites, and have higher needle cytokinin contents (von Schwartzenberg & Hahn, Journal of Plant Physiology 139, 218–223, 1991). Physiologically mature Sitka spruce (Picea sitchensis[Bong.] Carr) trees growing in a commercial plantation were sprayed with combinations of S, N and acidity from bud burst until December, for a 3 year period, in order to factor out the effects of individual pollutants and identify the specific component responsible for the high cytokinin content. Cytokinins were monitored using high‐performance liquid chromatography/enzyme‐linked immunosorbent assay techniques. After 3 years of treatment only needles of neutral N‐treated trees contained significantly higher levels of cytokinin than those of trees receiving no spray. The addition of acid S could suppress the effects of added N. Needles from neutral N treatments also contained significantly higher levels of biologically active cytokinins and forms that can be transported in the xylem/phloem. Significantly lower levels of active cytokinins were present in needles sprayed with N in combination with acid sulphate. The results demonstrate that the needle cytokinin content may be used as a sensitive and selective bioindicator of the early stages in N perturbation in coniferous trees.
Would transformation of C3 crop plants with foreign Rubisco increase productivity? A computational analysis extrapolating from kinetic properties to canopy photosynthesis
Authors: ZHU X.‐G. , PORTIS A. R. , LONG S. P. 
Published: December 2004

ABSTRACTGenetic modification of Rubisco to increase the specificity for CO2 relative to O2 (τ) would decrease photorespiration and in principle should increase crop productivity. When the kinetic properties of Rubisco from different photosynthetic organisms are compared, it appears that forms with high τ have low maximum catalytic rates of carboxylation per active site (kcc). If it is assumed that an inverse relationship between kcc and τ exists, as implied from measurements, and that an increased concentration of Rubisco per unit leaf area is not possible, will increasing τ result in increased leaf and canopy photosynthesis? A steady‐state biochemical model for leaf photosynthesis was coupled to a canopy biophysical microclimate model and used to explore this question. C3 photosynthetic CO2 uptake rate (A) is either limited by the maximum rate of Rubisco activity (Vcmax) or by the rate of regeneration of ribulose‐1,5‐bisphosphate, in turn determined by the rate of whole chain electron transport (J). Thus, if J is limiting, an increase in τ will increase net CO2 uptake because more products of the electron transport chain will be partitioned away from photorespiration into photosynthesis. The effect of an increase in τ on Rubisco‐limited photosynthesis depends on both kcc and the concentration of CO2 ([CO2]). Assuming a strict inverse relationship between kcc and τ, the simulations showed that a decrease, not an increase, in τ increases Rubisco‐limited photosynthesis at the current atmospheric [CO2], but the increase is observed only in high light. In crop canopies, significant amounts of both light‐limited and light‐saturated photosynthesis contribute to total crop carbon gain. For canopies, the present average τ found in C3 terrestrial plants is supra‐optimal for the present atmospheric [CO2] of 370 µmol mol−1, but would be optimal for a CO2 concentration of around 200 µmol mol−1, a value close to the average of the last 400 000 years. Replacing the average Rubisco of terrestrial C3 plants with one having a lower and optimal τ would increase canopy carbon gain by 3%. Because there are significant deviations from the strict inverse relationship between kcc and τ, the canopy model was also used to compare the rates of canopy photosynthesis for several Rubiscos with well‐defined kinetic constants. These simulations suggest that very substantial increases (> 25%) in crop carbon gain could result if specific Rubiscos having either a higher τ or higher kcc were successfully expressed in C3 plants.
Changes in carbohydrate composition of cucumber leaves during the development of powdery mildew infection
Authors: Abood J. K. , Lösel D. M. 
Published: December 2004

Within 3 days after inoculation, greater rates of decrease of hexoses, and of increases in inositol and α‐glucans, were detected in leaves of cucumber leaves infected with Sphaerotheca fuliginea (now reclassified as Podosphaera xanthii) than in healthy leaves, together with synthesis of fungal mannitol, arabitol and trehalose. With the onset of sporulation (5 days after inoculation, dai), glucose, polyols, trehalose and glycogen content, as well as fresh and dry weight of leaf tissue, increased more rapidly than in healthy plants, while sucrose, raffinose and starch declined. Starch, glycogen and other α‐glucans, extracted from ethanol‐insoluble tissue fractions of different water‐solubility from healthy and infected leaves, were quantified after amyloglucosidase treatment. Infection‐induced alterations in partitioning of photosynthate during a 14 h photoperiod at 7 dai, including a close correspondence in patterns of synthesis of glucose, polyols and glycogen, further clarified the process of diversion of host assimilate to the pathogen. The presence of glucose, but only traces of sucrose in spores, supported evidence from other powdery mildew infections for photosynthate being transferred to S. fuliginea as glucose.
Phenotypic and genotypic diversity of Phytophthora infestans populations in Scotland (1995–97)
Authors: Cooke D. E. L. , Young V. , Birch P. R. J. , Toth R. , Gourlay F. , Day J. P. , Carnegie S. F. , Duncan J. M. 
Published: December 2004

In a survey of Scottish potato late blight (Phytophthora infestans) populations from 1995 to 1997, nearly 500 isolates were collected from over 80 disease outbreaks in commercial potato crops and gardens/allotments. The isolates were characterized by mating type, resistance to the fungicide metalaxyl and almost 300 were examined by DNA‐based AFLP fingerprinting. These data were examined alongside cropping details to determine the population structure in the context of existing disease management strategies. A1 and A2 mating type isolates were present in both commercial potato crops and gardens or allotments although they coexisted more frequently in the latter sites. One‐fifth of the isolates collected were of the A2 mating type and the frequency was similar over the 3 years and amongst sites. In 1995 the proportions of isolates that were sensitive and resistant to metalaxyl were equal (∼40%) but, over the following 2 years, the frequency of resistant isolates decreased and that of intermediate isolates increased. The mating type response to metalaxyl differed markedly, with 52% of A1 and only 5% of A2 isolates being resistant. Considerable molecular diversity was observed, with over half of the isolates having unique AFLP patterns. Analysis of the molecular and phenotypic data revealed a broad clustering of the population into three groups. Many factors point to an A2 population restricted by its sensitivity to phenylamides. The majority of the A2 isolates were found in a single AFLP group, but the presence of mixed mating type samples, an increasing frequency of isolates of intermediate metalaxyl resistance and the extent of the AFLP diversity suggest occasional sexual recombination, and thus gene flow, between groups.
Relationship between potato seed tuber contamination by Erwinia carotovora ssp. atroseptica, blackleg disease development and progeny tuber contamination
Authors: Toth I. K. , Sullivan L. , Brierley J. L. , Avrova A. O. , Hyman L. J. , Holeva M. , Broadfoot L. , Pérombelon M. C. M. , McNicol J. 
Published: December 2004

The relationship between contamination of potato seed tubers with Erwinia carotovora ssp. atroseptica (Eca), blackleg disease development, and the incidence and level of progeny tuber contamination in field grown crops was studied in 1998, 1999 and 2000. Seed tubers were inoculated by vacuum infiltration at three levels (low, intermediate and high) with a streptomycin‐resistant marker strain of Eca (SCRI1039Str) and planted in the field. Blackleg disease development was directly related to the level of seed tuber contamination. The higher the level of seed tuber contamination, the earlier in the season blackleg disease appeared and the greater the final level of disease, which continued to rise as the season progressed. High and low levels of seed tuber contamination were related to high and low incidences of progeny tuber contamination, respectively, at all sampling times. However, an intermediate degree of seed tuber contamination tended to be associated with a low level of blackleg disease, a variable incidence of progeny tuber contamination early in the season but a high incidence later in the season. The level of progeny tuber contamination, derived from seed tubers inoculated at the three different levels of Eca, was categorized into four contamination classes (< 102, 102–103, 103–104 and > 104 marker strain colony‐forming units/mL peel extract). At the lowest level of seed tuber contamination, progeny tuber contamination tended to be in the two lower categories. However, as seed tuber contamination increased, the proportion of contaminated progeny tubers in the two higher categories also increased. Overall, the results suggest that progeny tuber contamination is related to seed tuber contamination and blackleg disease, and that the threshold level of seed tuber contamination remains an important factor in predicting both blackleg disease and tuber health.
Position of inoculum in the canopy affects the risk of septoria tritici blotch epidemics in winter wheat
Authors: Lovell D. J. , Parker S. R. , Hunter T. , Welham S. J. , Nichols A. R. 
Published: December 2004

The spread of septoria leaf blotch in wheat caused by Mycosphaerella graminicola is widely reported to depend on the occurrence of splashy rainfall. Previous studies have also implicated an important effect of canopy architecture on the risk of disease spread. This is because architecture affects the proximity of the yield‐forming leaves to inoculum present on older diseased leaves within the crop. This study demonstrated that infection of the final three leaves of winter wheat could occur in the absence of splashy rainfall. For cvs Riband and Longbow, the final two leaf layers emerged at a position ≈ 8 cm below older leaves containing sporulating lesions. Under these conditions, infection of new leaves occurred in treatments that simulated dew and nonsplashy rainfall. These treatments resulted in disease incidences of 10–40% above the untreated control on the final two leaf layers. Within a season, the distance between diseased and healthy leaves during the period of stem extension varied substantially across a range of 30 cultivars. While the magnitude of these differences was not the same across seasons, the relative differences between cultivars were generally consistent, suggesting a strong genotype influence on lesion proximity. This study shows how knowledge of the distribution of lesion proximity within a crop can be used to estimate the risk of inoculum transfer for a given maximum splash height. A rapid crop‐monitoring method for estimating the distribution of lesion proximity was developed and tested. Lesion proximity was manipulated by plant growth regulator (PGR) treatments. Significant increases in disease, between 14 and 62%, were observed on the upper canopy leaves of plants treated with PGR. The largest differences were observed in treatments where lesion proximity was most affected.
Estimation of Global Temperature Fields from Scattered Observations by a Spherical-Wavelet-Based Spatially Adaptive Method
Authors: Oh Hee-Seok , Li Ta-Hsin 
Published: December 2004

SummaryThe paper considers the problem of estimating the entire temperature field for every location on the globe from scattered surface air temperatures observed by a network of weather-stations. Classical methods such as spherical harmonics and spherical smoothing splines are not efficient in representing data that have inherent multiscale structures. The paper presents an estimation method that can adapt to the multiscale characteristics of the data. The method is based on a spherical wavelet approach that has recently been developed for a multiscale representation and analysis of scattered data. Spatially adaptive estimators are obtained by coupling the spherical wavelets with different thresholding (selective reconstruction) techniques. These estimators are compared for their spatial adaptability and extrapolation performance by using the surface air temperature data.
Genetic polymorphisms at Gli‐Dt gliadin loci in Aegilops tauschii as revealed by acid polyacrylamide gel and capillary electrophoresis
Authors: Yan Y. M. , Hsam S. L. K. , Yu J. Z. , Jiang Y. , Zeller F. J. 
Published: December 2004

AbstractGliadin variation at Gli‐Dt1 and Gli‐Dt2 loci in 198 Aegilops tauschii accessions was studied by acid polyacrylamide gel electrophoresis (A‐PAGE) and capillary electrophoresis (CE). High genetic polymorphisms were found at both gliadin coding loci, revealing a total of 184 and 169 gliadin variants at the Gli‐Dt1 and Gli‐Dt2 loci, respectively. In particular, 12 gliadin blocks encoded by different alleles were apparently expressed and readily identified in six synthetic hexaploids produced by hybridization between Triticum durum and Ae. tauschii accessions. Compared with Ae. tauschii ssp. eusquarrosa, the gliadin profile of the D genome in Ae. tauschii ssp. strangulata more resembles that of T. aestivum, supporting the view that the subspecies strangulata is the most likely progenitor of bread wheat. Capillary electrophoresis analysis showed that the method is capable of separating and characterizing gliadins with speed, in high resolution using small sample amounts, and is well‐suited to detect protein alleles and to identify desirable genotypes in wheat quality improvement.