bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Brassica napus extA extensin gene negative regulatory region controls expression in response to mechanical stresses
Authors: SHIRSAT A. H. , THOMSON H. E. C. , ELLIOTT K. A. 
Published: September 2003

ABSTRACTIn the present study the hypothesis that the −433 to −664 bp negative regulatory region (NRR) of the Brassica napus extA extensin promoter controls extA activation in response to externally applied weight loads was tested. When weight loads were applied to the nodal regions of transgenic tobacco plants containing extA promoter deletions fused to GUS, repression controlled by the NRR was overcome and GUS expression was induced only in the transgenics carrying the NRR. This proves that extensin expression in nodal regions is not developmentally controlled, but is induced in response to mechanical stresses, and is controlled by the NRR. It was also shown that the activation of the extA promoter during the development of lateral roots is a stress‐related response that is also under the control of the NRR but that the constitutive expression of extensin mRNA in the phloem of roots is not due to the mechanical forces the root experiences as it forces it way through the soil. Electrophoretic mobility shift assays using a 25 bp oligonucleotide have been used to show that an 8 bp consensus sequence from the NRR binds nuclear proteins. Wound‐induced signals regulating extensin gene expression are shown to travel bi‐directionally through the plant, from root to leaf and vice versa.
Natural variation in cadmium tolerance and its relationship to metal hyperaccumulation for seven populations of Thlaspi caerulescens from western Europe
Authors: ROOSENS N. , VERBRUGGEN N. , MEERTS P. , XIMÉNEZ‐EMBÚN P. , SMITH J. A. C. 
Published: September 2003

ABSTRACT Thlaspi caerulescens J. & C. Presl is a distinctive metallophyte of central and western Europe that almost invariably hyperaccumulates Zn to> 1.0% of shoot dry biomass in its natural habitats, and can hyperaccumulate Ni to> 0.1% when growing on serpentine soils. Populations from the Ganges region of southern France also have a remarkable ability to accumulate Cd in their shoots to concentrations well in excess of 0.01% without apparent toxicity symptoms. Because hyperaccumulation of Cd appears to be highly variable in this species, the relationship between Cd tolerance and metal accumulation was investigated for seven contrasting populations of T. caerulescens grown under controlled conditions in solution culture. The populations varied considerably in average plant biomass (3.1‐fold), shoot : root ratio (2.2‐fold), Cd hyperaccumulation (3.5‐fold), shoot : root Cd‐concentration ratio (3.1‐fold), and shoot Cd : Zn ratio (2.6‐fold), but the degree of hyperaccumulation of Cd and Zn were strongly correlated. Two populations from the Ganges region were distinct in exhibiting high degrees of both Cd tolerance and hyperaccumulation (one requiring 3 µM Cd for optimal growth), whereas across the other five populations there was an inverse relationship between Cd tolerance and hyperaccumulation, as has been noted previously for Zn. Metal hyperaccumulation was negatively correlated with shoot : root ratio, which could account quantitatively for the differences between populations in shoot Zn (but not Cd) concentrations. On exposure to 30 µM Cd, the two Ganges populations showed marked reductions in shoot Zn and Fe concentrations, although Cd accumulation was not inhibited by elevated Zn; in the other five populations, 30 µM Cd had little or no effect on Zn or Fe accumulation but markedly reduced shoot Ca concentration. These results support a proposal that Cd is taken up predominantly via a high‐affinity uptake system for Fe in the Ganges populations, but via a lower‐affinity pathway for Ca in other populations. Total shoot Cd accumulated per plant was much more closely related to population Cd tolerance than Cd hyperaccumulation, indicating that metal tolerance may be the more important selection criterion in developing lines with greatest phytoremediation potential.
Phosphorus (P) uptake and growth of a root hairless barley mutant (bald root barley, brb) and wild type in low‐ and high‐P soils
Authors: GAHOONIA T. S. , NIELSEN N. E. 
Published: September 2003

ABSTRACTThe recently isolated root‐hairless mutant of barley (Hordeum vulgare L), bald root barley, brb offers a unique possibility to quantify the importance of root hairs in phosphorus (P) uptake from soil. In the present study the ability of brb and the wild‐type, barley genotype Pallas producing normal root hairs to deplete P in the rhizosphere soil was investigated and the theory of diffusion and mass flow applied to compare the predicted and measured depletion profiles of diffusible P. Pallas depleted twice as much P from the rhizosphere soil as brb. The P depletion profile of Pallas uniformly extended to 0.8 mm from the root surface, which was equal to the root hair length (RHL). The model based on the theory of diffusion and mass flow explained the observed P‐depletion profile of brb, and the P depletion outside the root‐hair zone of Pallas, suggesting that the model is valid only for P movement in rhizosphere soil outside the root‐hair zone. In low‐P soil (P in soil solution 3 µm) brb did not survive after 30 d, whereas Pallas continued to grow, confirming the importance of root hairs in plant growth in a P‐limiting environment. In high‐P soil (P in soil solution 10 µm) both brb and Pallas maintained their growth, and they were able to produce seeds. At the high‐P concentration, RHL of the Pallas was reduced from 0.80 ± 0.2 to 0.68 ± 0.14 mm. In low‐P soil, P‐uptake rate into the roots of Pallas was 4.0 × 10−7 g mm−1 d−1 and that of brb was 1.9 × 10−7 g mm−1 d−1, which agreed well with the double amount of P depleted from the rhizosphere soil of Pallas in comparison with that of brb. In high‐P soil, the P uptake rates into the roots of brb and Pallas were 3.3 and 5.5 × 10−7 g mm−1 d−1, respectively. The results unequivocally confirmed that in a low‐P environment, root hairs are of immense importance in P acquisition and plants survival, but under high‐P conditions they may be dispensable. The characterization of phenotypes brb and Pallas and the ability to reproduce seeds offers a unique possibility of molecular mapping of QTLs and candidate genes conferring root‐hair formation and growth of barley.
A hydromechanical and biochemical model of stomatal conductance
Authors: BUCKLEY T. N. , MOTT K. A. , FARQUHAR G. D. 
Published: September 2003

ABSTRACTA mathematical model of stomatal conductance is presented. It is based on whole‐plant and epidermal hydromechanics, and on two hypotheses: (1) the osmotic gradient across guard cell membranes is proportional to the concentration of ATP in the guard cells; and (2) the osmotic gradient that can be sustained per unit of ATP is proportional to the turgor pressure of adjacent epidermal cells. In the present study, guard cell [ATP] is calculated using a previously published model that is based on a widely used biochemical model of C3 mesophyll photosynthesis. The conductance model for Vicia faba L. is parameterized and tested As with most other stomatal models, the present model correctly predicts the stomatal responses to variations in transpiration rate, irradiance and intercellular CO2. Unlike most other models, however, this model can predict the transient stomatal opening often observed before conductance declines in response to decreases in humidity, soil water potential, or xylem conductance. The model also explicitly accommodates the mechanical advantage of the epidermis and correctly predicts that stomata are relatively insensitive to the ambient partial pressure of oxygen, as a result of the assumed dependence on ATP concentration.
Rheological differences between Archaean and younger crust can determine rates of Quaternary vertical motions revealed by fluvial geomorphology
Authors: Westaway Rob , Bridgland David , Mishra Sheila 
Published: September 2003

AbstractSurface uplift is widely observed in subaerial regions of continental crust that are distant from plate boundaries, often revealed by river terrace staircases with altitude ranges of several hundred metres, which typically span the Quaternary. This characteristic geomorphology has been explained by forcing of flow in the weak lower‐crustal layer by surface processes: non‐steady‐state erosion and cyclical loading by ice‐sheets and sea‐level fluctuations. This study tests this interpretation, by showing that analogous river‐terrace staircases are absent in Archaean crust, which lacks the weak lower‐crustal layer found elsewhere.
Post‐nappe brittle extension in the inner Western Alps (Schistes Lustrés) following late ductile exhumation: a record of synextension block rotation?
Authors: Agard P. , Fournier M. , Lacombe O. 
Published: September 2003

AbstractFault data collected from the Schistes Lustrés domain point to the existence of successive steps of deformation and indicate that extension is not multidirectional. This study underlines the continuity between the patterns of late brittle/ductile exhumation tectonics and brittle deformation, and strenghtens the view that extensional movements dominate in shallow levels of the inner Western Alps since at least 35–30 Ma. The progressive clockwise rotation of the earliest directions of extension with time is compatible with the amount of anticlockwise rotation from c. 35 Ma determined by recent palaeomagnetic studies, whereas the last documented N–S extension may reflect a short‐lived stage of orogen‐parallel extension.
Vertical movements in and around the south‐east Carpathian foredeep: lithospheric memory and stress field control
Authors: Bertotti G. , Ma⃛enco L. , Cloetingh S. 
Published: September 2003

AbstractA > 10‐km‐thick basin formed in Tertiary to Quaternary times in front and overlapping with the south‐east Carpathians. The Focşani Depression is part of this system and overlies the Vrancea seismogenetic volume, thought to correspond to the remnants of the continental slab subducted beneath the Carpathians. Slab detachment and its lateral migration are considered to control vertical movements in the area. We present the first complete analysis of subsidence patterns in the Depression and derive a substantially different picture. The strongest subsidence is Sarmatian in age, coeval with the main nappe emplacement events. Subsequently, subsidence did not stop and persisted until present times despite cessation of thrusting. The main depocentre remained the Focşani Depression and no significant lateral migration is detected. Post‐Sarmatian subsidence is contemporaneous with major exhumation/erosion in the Carpathians. The evolution of the basin is associated with a combination of vertical and far‐field horizontal stresses, and its position is controlled by pre‐existing lithospheric heterogeneities.
High‐ to ultrahigh‐pressure (UHP) ductile shear zones in the Sulu UHP metamorphic belt, China: implications for continental subduction and exhumation
Authors: Zhao Z. Y. , Fang A. M. , Yu L. J. 
Published: September 2003

AbstractHigh‐ to ultrahigh‐pressure (HP‐UHP) metamorphic rocks that resulted from deep continental subduction and subsequent exhumation in the Sulu orogenic belt, China, have experienced multiphase deformation and metamorphic overprint during its long journey to the mantle and return to the surface. HP‐UHP shear zones are strain‐localized weak zones on which the UHP slab is transported over long distances. HP‐UHP shear zones are well exposed along a 200‐km belt in the Sulu UHP metamorphic belt. The shear zones lie structurally below the UHP rocks and above the non‐UHP rocks, suggesting the early exhumation of the UHP rocks by thrusting. The large area distribution, HP‐UHP nature, high strain and structural association of the shear zones with the UHP rocks suggest that the shear zones are probably a regional detachment developed during the early stage of exhumation of the UHP rocks. Kinematic indicators suggest top‐to‐the N–NW motion of the UHP slab during the exhumation, which, combined with isotope signature in Mesozoic igneous rocks, leads us to the interpretation that the subduction polarity is the North China plate down to the south rather than the Yangtze plate down to the north in the Sulu region.
On the number and spacing of faults
Authors: Morellato Chiara , Redini Francesco , Doglioni Carlo 
Published: September 2003

AbstractOrogens and rift zones have a finite number of regional faults. The accretionary prisms analysed here have a number of thrusts < 50, whereas extensional areas have a number of normal faults ranging between six and 44. The average spacing of thrusts is between 5 and 25 km; spacing of normal faults is more restricted into two peaks, at 25–29 km and 4–6 km, in which the latter is the most common. The number and spacing of faults appear to be mainly controlled by the depth of the decollement plane, which seems to be more variable in compressive settings with respect to rift zones. Basement‐involved orogens present fewer and more spaced thrusts; by contrast, a greater number of thrusts with shorter spacing characterize thin‐skinned thrust belts. The shallower the decollement is, the stronger it appears to control the palaeogeography, in the sense of rheological lateral variations in the sedimentary cover.
Offshore granulites from the Bay of Biscay margins: fission tracks constrain a Proterozoic to Tertiary thermal history
Authors: Fügenschuh Bernhard , Froitzheim Nikolaus , Capdevila Raymond , Boillot Gilbert 
Published: September 2003

AbstractZircon and apatite fission track ages were determined on granulites dredged along the Bay of Biscay margins. A sample from Ortegal Spur (Iberia margin) yielded 725 ± 67 Ma (zircon). A sample from Le Danois Bank (Iberia margin) yielded 284 ± 58 Ma (zircon), indicating post‐Variscan cooling. Apatite from this sample gave 52 ± 2 Ma, interpreted as final cooling after ‘Pyrenean’ thrust imbrication. Two other samples from Le Danois Bank have Early Cretaceous apatite ages (138 ± 7 and 120 ± 8 Ma), interpreted to result from exhumation during rifting. Finally, a granulite from Goban Spur (Armorican margin) gave 212 ± 10 Ma (apatite), coinciding with a precursory rifting phase. Together with published radiometric results, these data indicate a Precambrian high‐grade terrane at the site of the current margins. The distribution of the granulites on the seafloor reflects tectonic and erosional processes related to (a) Mesozoic rifting and (b) Early Tertiary incipient subduction of the Bay of Biscay beneath Iberia.
Five‐year incidence of diabetic retinopathy in the Melbourne Visual Impairment Project
Authors: McCarty Daniel J , Fu Cara L , Harper C Alex , Taylor Hugh R , McCarty Catherine A 
Published: September 2003

Abstract Background: The purpose of the present paper was to describe the 5‐year incidence and progression of diabetic retinopathy in the Melbourne Visual Impairment Project (VIP) cohort. Methods: Baseline examinations were conducted from 1992 to 1994 and follow‐up data were collected 5 years later. Data collected during the baseline and follow‐up studies included medical history (including previous diag­nosis of diabetes mellitus) and dilated fundus examination. Two 30° stereoscopic fundus photographs were taken with a Topcon TRC fundus camera, one centred on the optic disc and the other centred on the fovea. Photographs from participants who reported having diabetes were graded for diabetic retinopathy based on an extension of the Modified Airlie House Classification. Grouping of participant data into retinopathy grades was based on the results of the worst eye. Results: The follow‐up survey included 82% (n = 121) of those with diabetes at baseline. Prevalence of any retino­pathy was 35.7% and macular oedema was 13% at follow up. Diabetic retinopathy was newly detected in 8/73 (5‐year incidence = 11.0%, 95% confidence interval (CI) = 3.8−18.1). Disease progression was seen in 9/31 participants (29.0%, 95%CI = 14.9−47.8) who had diabetic retinopathy at baseline. The 5‐year incidence of proliferative diabetic retino­pathy in people without proliferative diabetic retinopathy at baseline was 2.9% (3/104, 95%CI = 0−6.4). The 5‐year incidence of macular oedema in people who did not have macular oedema at baseline was 8.0% (8/100, 95%CI = 2.7−13.3). All people with proliferative diabetic retinopathy at baseline had received laser treatment by the follow‐up survey. Twenty‐four per cent of people without diabetic retinopathy reported never having had a dilated fundus examination (excluding the VIP examinations). Conclusion: The 5‐year incidence of diabetic retinopathy was 11% in the Melbourne Visual Impairment Project. Most people with proliferative diabetic retinopathy or macular oedema are receiving treatment. However, many people with diabetes are not having regular dilated fundus examinations.
Comparison of scleral buckling with combined scleral buckling and pars plana vitrectomy in the management of rhegmatogenous retinal detachment with unseen retinal breaks
Authors: Tewari Hem K , Kedar Sachin , Kumar Atul , Garg Sat P , Verma Lalit K 
Published: September 2003

Abstract Background: The purpose of the present paper was to compare the techniques of conventional scleral buckling and combined pars plana vitrectomy and scleral buckling procedures in rhegmatogenous retinal detachments with unseen retinal breaks. Methods: Forty‐four consecutive eyes with uncomplicated, primary rhegmatogenous retinal detachments with a clear media and unseen retinal breaks were randomized to two groups. The scleral buckling group underwent 360° scleral buckling, cryopexy and external subretinal fluid drainage. In the combined surgery group, 360° scleral buckling, pars plana vitrectomy, air−fluid exchange, endolaser and injection of 14% perfluoropropane gas was done. Results: At 3 months follow up the primary reattachment rate was 80% (16/20 cases) in the combined surgery group, and 70% (14/20 cases) in the scleral buckling group (P = 0.716). The visual acuity improved significantly from a preoperative median of hand movement (HM; range: HM to 6/60; similar in both the groups), to a median of 6/60 (range: perception of light to 6/18) in the combined surgery group and a median of 6/36 (range: HM to 6/18) in the scleral buckling group, the difference between the two groups not being statistically significant (P = 0.4). The number of intraoperative and postoperative complications was more in the combined surgery group. (four cases were lost to follow up and were doing well when last examined.) Conclusion: Conventional scleral buckling was found to be a safe and effective technique in the primary management of uncomplicated, rhegmatogenous retinal detachments with unseen retinal breaks when the media is clear.
Effect of whiplash injury on accommodation
Authors: Brown Shayne 
Published: September 2003

Abstract Background: Accommodative disturbance has been cited as one of the causes of visual disturbance following whiplash injury but to date, with one exception, none of the studies have incorporated a group of control subjects; none of the results have been statistically analysed. The aim of the present study was to examine the amplitude of accommodation in a group of whiplash subjects, the majority of whom had specifically complained of visual/ocular symptoms. Methods: The whiplash group consisted of 19 subjects and the control group consisted of 43 subjects. The amplitude of accommodation of the right and left eyes of the whiplash and control group subjects was measured and the results of the two groups compared. Results: There was reduced amplitude of accommodation of the right (P = 0.02) and left (P = 0.02) eyes in the whiplash group subjects compared to the control group subjects. Conclusion: These results indicate that whiplash was associated with defective accommodation in the present select group of whiplash subjects.
New paediatric contrast test: Hiding Heidi low‐contrast ‘face’ test
Authors: Chen Ai Hong , Mohamed Diana 
Published: September 2003

ABSTRACT Background: The Hiding Heidi low‐contrast ‘face’ test is a new paediatric contrast test to evaluate the ability to detect objects with low contrast. The purpose of the present study was to compare the Hiding Heidi low‐contrast ‘face’ test (HH) with the Pelli−Robson contrast sensitivity test (PR) and the functional acuity contrast test (FACT) in the low‐contrast assessment. Methods: Thirty university students participated in the present study. The contrast ability was evaluated by using three different methods: HH, PR and FACT. The HH was repeated on two separate occasions to test the repeatability. Results: There was a significant positive correlation between HH and PR (r = 0.65, P < 0.01); between HH and FACT at 6 cycles per degree (c.p.d.; r = 0.64, P < 0.01); between HH and FACT at 3 c.p.d. (r = 0.91, P < 0.01); and between HH and FACT at 1.5 c.p.d. (r = 0.56, P < 0.01). The paired t‐test showed a significant difference between HH and PR (t = −6.05, P < 0.01); between HH and FACT at 6 c.p.d. (t = −11.16, P < 0.01); between HH and FACT at 3 c.p.d. (t = −8.35, P < 0.01); and between HH and FACT at 1.5 c.p.d. (t = −5.64, P < 0.01). They had good agreement. The HH had a high repeatability. Conclusions: The HH had a positive correlation but produced significantly different readings when compared with FACT and PR. The features and role of HH in clinical contrast sensitivity assessment are discussed.
Quantitative model demonstrating that recombinant adeno‐associated virus and green fluorescent protein are non‐toxic to the rat retina
Authors: Daniels Dru M , Shen Wei‐Yong , Constable Ian J , Rakoczy P Elizabeth 
Published: September 2003

ABSTRACT Background: Recombinant adeno‐associated virus (rAAV) is one of the most promising recombinant viral vectors for delivering therapeutic agents to the retina. The present study aims to quantify any effect that an rAAV construct may have on the retina. To be able to use rAAV for therapeutic purposes, the potentially toxic effect of the vector and an associated green fluorescent protein (gfp) marker has to be investigated. Methods: By combining histological analysis with computer scanning techniques, the local toxicity of rAAV and gfp can be measured. This will have obvious implications for its role as a carrier in the rapidly developing world of gene therapy. Results: It is shown that a construct consisting of rAAV and gfp, delivered subretinally to rat eyes, causes no more histological damage than injection with saline alone. Furthermore, via fluorescent fundus photography and computer scanning techniques it is seen that the area exposed to the rAAV−gfp construct is significantly greater than the area of histological change. Conclusions: It is thus concluded that the rAAV−gfp construct has no significant toxic effect, at an anatomical level, on the retina 12 months after injection.