bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterisation of the pituitary gonadotrophs of FSH‐receptor knockout mice
Authors: Widen A. , Christian H. C. , Abel M. H. , Charlton H. M. , Morris J. F. 
Published: March 2003

To investigate further brain‐pituitary‐gonadal interrelationships we have generated mice in which the gene encoding the FSH receptor has been disrupted (FSHRKO). FSHRKO females but not males are infertile. Compared with control animals, serum concentrations of LH and FSH and pituitary content of FSH are significantly increased in female FSHRKO (Abel et al. Endocrinology141, 2000). The aim of the present study was to correlate these physiological differences in gonadotroph function of 8‐week‐old‐female normal and FSHRKO mice with a structural analysis of their gonadotrophs. Gonadotrophs were identified by LH‐immunogold labeling for electron microscopy and gonadotroph frequency estimated from 1 (m sections immunolabelled for LH. In FSHRKO the frequency, cell and nuclear profile areas of gonadotrophs did not differ significantly from that in normal mice. Surprisingly the endoplasmic reticulum appeared normal and undilated despite the lack of oestradiol feedback in the KO animals. LH‐immunoreactive cells in female FSHRKO had significantly (P < 0.05) larger secretory granules 176(7 nm) diameter, mean(SEM) compared to normal mice 139(7 nm) but there was no significant difference in the granule area/cytoplasmic area. The subpopulation of granules in which an electron‐dense core was present in a more electron‐lucent ‘halo’ was absent in FSHRKO gonadotrophs. The increased pituitary FSH stores in FSHRKO mice therefore appear to be represented by the formation of larger secretory granules in which the packaging of hormone is less dense. Interestingly, despite being infertile and lacking biologically active estrogen, the alterations in FSHRKO pituitary morphology are relatively subtle compared to normal mice.
A rare case of polyarticular synovial osteochondromatosis
Authors: Seckley J. , Anderson S. G. , Snow T. M. , Benjamin M. 
Published: March 2003

Synovial osteochondromatosis is a rare condition characterised by the production of multiple nodules of hyaline cartilage within the subsynovial connective tissue of joints, tendons and bursae. The nodules of proliferative cartilage may remain attached to the synovial membrane or detach to form loose bodies in the synovial cavity. Most reported cases have been of the monoarticular form of the disease, with the majority in the knee and hip. Polyarticular forms comprise only 5% of cases.Here we report a case of polyarticular synovial osteochondromatosis in a dissecting room cadaver (female; 76 y). Multiple, calcified, intra‐ and extra‐articular nodules (n = 14) were located bilaterally in the elbow, proximal radioulnar and shoulder joints. They had a lustrous, cobblestone‐like appearance and the largest (27 mm) was located in the anteromedial aspect of the right elbow joint. The smallest (5 mm) was deep to the annular ligament of the left proximal radioulnar joint.Signs of cartilage degeneration (fissuring and chondrocyte clustering), similar to those well documented in osteoarthritis, were observed histologically. Articular cartilage covered only a small area of the nodules while periosteum dominated the remaining surface. Thin sparsely distributed spicules of spongy bone were seen inside the nodules, separated by regions of fatty marrow.The affected joints also showed signs of osteoarthritis. This is consistent with the common view that osteoarthritis is a secondary complication of synovial osteochondromatosis. However osteoarthritic change was also evident in other joints.
Immunohistochemical localization of BDNF‐, TrkB‐ and TrkA‐like proteins in the teleost lateral line system
Authors: Germana A. , Catania S. , Cavallaro M. , González‐Martínez T. , Ciriaco E. , Hannestad J. , Vega J. A. 
Published: March 2003

AbstractThe lateral line system, formed of both superficial (pit organs) and canal neuromasts, is one of the major mechanosensory systems in fish. It has always been assumed that this system depends on neurotrophins and their cognate Trk receptors for development and maintenance, as has been shown in other mechanosensitive systems of vertebrates. However, until now this issue has not been specifically addressed. In this study we used immunohistochemistry to investigate the occurrence and localization both of neurotrophins (NGF‐, BDNF‐ and NT‐3‐like) and of Trk‐like proteins (TrkA‐, TrkB‐, TrkC‐like) in alevins of Salmo salar and S. trutta. All cells in the pit organs of S. salar displayed strong immunoreactivity for TrkB‐like and BDNF‐like, whereas they were restricted to the hair cells in S. trutta. The hair, supporting and mantle cells of S. salar, and the mantle cells of S. trutta, also expressed TrkA‐like immunoreactivity. In the canal neuromasts BDNF‐, TrkA‐ and TrkB‐like proteins were present in all cells, without differences between species. NGF‐, NT‐3‐ and TrkC‐like immunoreactivity were never detected. The present results suggest that mechanoreceptive hair cells, as well as supporting cells, in the lateral line system are under the control of the BDNF–TrkB‐like complex, and probably of ligands of TrkA‐like receptors.
Patterning the limb before and after SHH signalling
Authors: Panman Lia , Zeller Rolf 
Published: March 2003

AbstractThe vertebrate limb is one of the most relevant experimental models for analysing cell–cell signalling during patterning of embryonic fields and organogenesis. Recently, the combination of molecular and genetic studies with experimental manipulation of developing limb buds has significantly advanced our understanding of the complex molecular interactions co‐ordinating limb bud outgrowth and patterning. Some of these studies have shown that there is a need to revise some of the textbook views of vertebrate limb development. In this review, we discuss how signalling by the polarizing region is established and how limb bud morphogenesis is controlled by both long‐range and signal relay mechanisms. We also discuss recent results showing that differential mesenchymal responsiveness to SHH signalling is established prior to its expression by the polarizing region.
Functional leaf attributes predict litter decomposition rate in herbaceous plants
Authors: CORNELISSEN J. H. C. , THOMPSON K. 
Published: March 2003

SUMMARYWe tested the hypothesis that functional attributes of living leaves provide a basis for predicting the decomposition rate of leaf litter. The data were obtained from standardized screening tests on 38 British herbaceous species. Graminoid monocots had physically tougher leaves with higher silicon contents than did herbaceous dicots, and this corresponded with the lesser decomposibility of the former. Total base content of living leaves was a good predictor of litter decomposition rate, but the evolutionary and ecological basis for this relationship appeared to differ between graminoid monocots and herbaceous dicots. In the monocots, litter decomposition rate was strongly predicted by leaf potassium content, which appeared to reflect other growth‐ related plant attributes such as seedling maximum relative growth rate, foliar nitrogen and phosphorus content, specific leaf area and short leaf lifespan. In the dicots the relationship between total leaf base content and litter decomposition rate was not unambiguously explained by growth‐related leaf attributes, possibly because of the considerable calcium uptake by dicots, which varies according to calcium availability in the soil.
Growth of 27 herbs and grasses in relation to ozone exposure and plant strategy
Authors: PLEIJEL H. , DANIELSSON H. 
Published: March 2003

SUMMARYPotted specimens of 27 Swedish native herbs and grasses were exposed to three different ozone concentrations, CF (charcoal filtered air), NF (non‐filtered air) and NF+ (1.5 × non‐filtered air) in open‐top chambers from 2 July to 5 August 1994. The species represented a wide range of different plant strategies according to the C‐S‐R model. The results show that the stress‐tolerators, S, had a smaller mean relative growth rate, R̄, during the exposure period and also a smaller accumulation of biomass compared with other strategies. The species with the intermediate strategy, CSR, had a R̄ similar to that of the species with a large component of C, the competitor strategy, and/or R, the ruderal strategy, whereas the net accumulation of biomass was smaller in the CSR group. This difference between R̄ and net growth for the CSR species compared to the species of other strategies, can be explained by a slower growth for the CSR group during the establishment phase. In the present investigation the response to ozone was very small regardless of plant strategy, although there was a weak trend towards slower growth with higher ozone concentration, 18 out of 27 species having a greater growth in CF than in NF +. The growth of one typical stress‐tolerant species, Festuca ovina L., was stimulated significantly by ozone. Visible injury, most likely caused by ozone, was noticed in three species, Dactylis glomerata L., Dactylis aschersoniana Graebn. and Phleum alpinum L. Although there were no major restrictions to plant growth in terms of water, nutrients or space in the present open‐top chamber experiment, the variability in all climatic factors was as large as in the ambient air. This might harden the plants and make them less sensitive to ozone compared to plants grown in the laboratory under controlled and optimal conditions with low variability.
The uptake of gaseous sulphur dioxide by non‐gelatinous lichens
Authors: CRIES CORINNA , SANZ MARIA‐JOSE , ROMAGNI JOANNE G. , GOLDSMITH STEVEN , KUHN UWE , KESSELMEIER JÜRGEN , NASH THOMAS H. 
Published: March 2003

SUMMARYIn two open, flow‐through systems 11 lichen species were fumigated with concentrations between 0–036 and 2–0 ppm (c. 94.3–5240 μg m−3) SO2. Sulphur dioxide uptake was monitored concurrently as a mass balance between incoming and outgoing SO2 concentrations. The rate of uptake ranged from 0.025 (±0.006) to 0.7 (±0.16) nmol SO2 g−1 d. wt s−1, for all species. After the first hour of fumigation the uptake rate was almost constant during the following 5 h for concentrations up to 1.0 ppm SO2. At higher concentrations the uptake declined over time continuously. Within the range of measured SO2 concentrations the uptake rate was linearly correlated with SO2 concentrations (r2= 0.90). Thalli which were killed by heat treatment or in which respiration was inhibited by azide treatment did not show significantly different SO2 uptake from living thalli. No differences in uptake were found during fumigation in the light versus in the dark.
Host plant stimulates hypaphorine accumulation in Pisolithus tinctorius hyphae during ectomycorrhizal infection while excreted fungal hypaphorine controls root hair development
Authors: BÉGUIRISTAIN THIERRY , LAPEYRIE FRÉDÉRIC 
Published: March 2003

summaryThe hypaphorine concentration in Pisolithus tinctorius Coker & Couch hyphae colonizing Eucalyptus roots was 3 to 5 times higher than in adjacent parts of the fungal colony. This phenomenon, observed 24 h after inoculation, was also recorded in several‐month‐old, well‐established ectomycorrhizas. Accumulation was controlled by specific root‐derived diffusible molecules: it can be induced through a membrane, but not by non‐host plants. In pure culture, high hypaphorine concentration was found only in the youngest mycelium, i.e. the outer 2 mm of the colony. Fungal hypaphorine had no IAA‐like activity on Eucalyptus root development and therefore could not be considered as an auxin analogue; instead, a strong reduction of root hair elongation was recorded.
Patch formation and developmental polarity in mycelial cord systems of Phanerochaete velutina on a nutrient‐depleted soil
Authors: WELLS JOHN M. , DONNELLY DAMIAN P. , BODDY LYNNE 
Published: March 2003

SUMMARYDevelopment of mycelial cord systems of Phanerochaete velutina (DC.: Pers.) Parmasto from 4‐cm3 inocula on a nutrient‐depleted non‐sterile soil was studied in laboratory microcosms using image analysis techniques. Cord systems were “baited” after 13d growth with either fresh, non‐sterile 4‐cm3 wood baits or control Perspex® blocks of the same contact area placed behind the foraging mycelial front. After 26 d growth, mycelial ‘patches’ arose by dedifferentiation of consolidated mycelial cords in both wood‐ and Perspex‐baited cord systems. ‘Patches’ comprised fine, highly branched separate hyphae extending radially from points of aggregated hyphae in cords. ‘Patches’ and cords could be readily distinguished by image analysis and the areas covered by patches and cords could be measured and compared. Whilst the total hyphal cover of Perspex‐ and wood‐baited systems did not differ significantly (P > 0.05), patch cover in wood‐baited systems was up to 10 times greater than in Perspex‐baited systems. Patches were temporary structures, regressing more rapidly with age than mycelial cords. Patch development ceased after application of a nutrient solution which replenished phosphate levels in the soil. Wood‐baited mycelial systems displayed significant developmental polarity (P≤ 005) of both total hyphal cover (patches plus cords) and hyphae in patches towards the ‘baited’ sector of cord systems after 42 d, which corresponded with peak patch development. However, significant (P≤ 0.05) developmental polarity of the mycelial systems along the bait‐inoculum line could be detected 8 d before patch formation when assessed by fractal geometry. Radiotracer studies showed that mycelial patches were not sinks for supplied 32P, but that they were sites of increased nutrient uptake capacity compared with that of mycelial cords. We discuss the need for mycelial cord systems to balance allocation of mycelial biomass between the two essential processes of colonizing wood resource units, and the acquisition of soluble inorganic nutrients from soil.
Introgression, tagging and expression of a leaf senescence gene in Festulolium
Authors: THOMAS HOWARD , EVANS CLIVE , THOMAS HUW MARTIN , HUMPHREYS MICHAEL W. , MORGAN GARETH , HAUCK BARBARA , DONNISON IAIN 
Published: March 2003

summaryA mutation of a gene (discovered in Festuca pratensis Huds. and designated sidy) confers indefinite greenness on senescing leaves. Via intergeneric hybrids with Lolium multiflorum L. and Lolium perenne L., the mutant gene (sidy) has been introgressed into a range of Lolium backgrounds. Using genomic in situ hybridization we have identified segments carrying sidy in recombinant chromosomes of Lolium–Festuca introgression lines. We also used L. perenne lines segregating 1:1 for the staygreen character to tag the gene with molecular markers. In two mapping populations a total of 84 genotypes were screened with isoenzymes, RAPD primers, RFLP probes and AFLP primer pairs. Over 180 polymorphic loci were identified, representing 10 linkage groups spanning 600 cM. Two AFLP markers are linked to sid at 4.6 and 14.9 cM, close enough to be usable for marker‐assisted selection. Introgression of sidy into Lolium temulentum L. resulted in the production of near‐isogenic inbreeding lines suitable for comparative studies of gene expression. Using a variation of the method of representational difference analysis a very small number of cDNAs have been identified as promising candidates for sid, or genes directly regulated by sid.
Differential tolerance to copper and zinc of micropropagated birches tested in hydroponics
Authors: UTRIAINEN M. A. , KÄRENLAMPI L. V. , KÄRENLAMPI S.O. , SCHAT H. 
Published: March 2003

summaryCopper and zinc tolerances of 10 micropropagated birch (Betula pendula and B. pubescens) clones were studied in hydroponic culture. Tolerance indices were determined, based on the mean growth rate of the longest root in 1 wk. A seed‐derived clone (142A), from a lead/Zn‐contaminated site showed more tolerance to Cu and Zn than bud‐derived clones (HA02 and HA18) from a Cu/nickel‐contaminated site or an ozone‐tolerant clone (KL‐2‐M) from an uncontaminated area. For Cu, the EC50 values were 30, 14, 8 and 11 μM in clones 142A, HA02, HA18 and KL‐2‐M, respectively. FOT Zn, the EC50 s were 4000 and 350 μM in clones 142A and KL‐2‐M, respectively. The relative Cu and Zn tolerances of the other clones were estimated by growing the plants in 30 μ CuSO4, and in 2000 or 350 μM ZnSO4, respectively. It is of interest that the Zn‐tolerant clone 142A was tolerant to Cu, although this metal was present at a very low concentration in the soil where the parent tree grows. Another clone (142B), from another seed of the same parent tree, was tolerant neither to Zn nor Cu. Compared with their own EC20s for root growth for Cu, 142A took up more Cu than KL‐2‐M, suggesting that the higher tolerance of the former clone is not explained by reduced uptake of Cu. The Zn uptake in clones 142A and KL‐2‐M was studied at 4000 μM and 800 μM Zn, respectively. Interestingly, the roots of both clones contained the same amount of Zn, even though clone 142A was exposed to a fivefold concentration of Zn.
The δ15N of lettuce and barley are affected by AM status and external concentration of N
Authors: AZCÓN‐G.‐AGUILAR ROSARIO , HANDLEY L. L. , SCRIMGEOUR C. M. 
Published: March 2003

Mean δ15N of whole‐plants of lettuce and barley varied by 3‰ when given a chemically and isotopically uniform N source. This variation was related to the presence, absence and species of arbuscular mycorrhizal (AM) fungi and to external N concentration. A highly AM‐susceptible plant (lettuce) responded to treatments differently than a less susceptible one (barley). The largest change in whole plant δ15N was related to the experimental combination most likely to be found in field conditions: species of fungus interacting with varying external concentrations of N.The mechanisms underlying observed variations of plant δ15N are not understood, nor can they be approached directly using δ15N. However, descriptive data, such as presented here, are important to the development of a mechanistic model, because they suggest relationships for future research, using inter alia15N‐enriched tracers. They also confirm that plant N sources, cannot be identified using plant δ15N, even when the type of mycorrhizal association (endo vs. ecto) is known.
Improvement of the 15N dilution method for estimation of absorption of NOx by plants supplied with 15N‐labelled fertilizer
Authors: QIAO Z. , MURRAY F. 
Published: March 2003

To develop further the methods for estimation of NOx absorption by plants supplied with 15N‐labelled fertilizer, we proposed a new calculation method, total N fixed method (TNF), and compared with the 15N dilution method and the classical mass balance method (MB).Hydroponically grown soybean plants were supplied with 15N‐labelled nitrate and exposed to 200–250 nl l−1 NO2 for 7 d. The proportions of the N derived from NO2 to total N in exposed plants were estimated by the three methods.The reported rates of NO2 absorption by several plant species, estimated by the 15N dilution method, were recalculated using the TNF method. The results of the two methods were compared and showed that: (1) The 15N dilution method overestimated the content of NO2‐N in exposed plants compared with the MB method whilst the TNF method produced estimations of NO2‐N closer to those by the MB method when the plants were supplied with 5 mM nitrate.
(2) The differences in estimations between the MB method and either the 15N dilution method or the TNF method increased with decreasing supply of 15N‐labelled nitrate to roots.
Diaphragms and flooding survival
Authors: Armstrong W. 
Published: March 2003

Why don't the gas spaces of submerged organs of wetland plants flood extensively when damaged? In addressing this intriguing question, Soukup et al. (pp. 71–75 in this issue) report on the role of rhizome diaphragms as barriers to flooding in Phragmites australis. This should prompt some reappraisal of the ways in which flooding resistance can be realized, even perhaps in undamaged organs.Most emergent wetland macrophytes have an abundance of interconnected internal gas space, much of it in the form of large voids transversely partitioned at intervals by perforated cellular plates termed diaphragms. Functionally, it provides a low‐resistance pathway for internal oxygen transport to support the respiratory needs of submerged and buried organs (Armstrong, 1979; Armstrong et al., 1988; Crawford, 1992) and facilitates carbon dioxide removal. However, it does more than this, since it enables oxygen to be released from the root to where it can support aerobic microbial activity in otherwise anaerobic sediments, and phytotoxin immobilization or destruction (Armstrong et al., 1992; Begg et al., 1994; Gilbert & Frenzel, 1998). This oxygen release is regarded by some as a valuable aid to effluent purification by constructed wetlands. Perhaps a less desirable property of this gas‐space provision is its recently discovered role in enhancing the emissions of greenhouse gases such as methane from wetlands (Brix et al., 1992; Chanton & Whiting, 1996; Crutzen, 1991; Dacey & Klug, 1979).
Ontogeny modifies the effects of water stress on stomatal control, leaf area duration and biomass partitioning of Pennisetum glaucum
Authors: Winkel T. , Payne W. , Renno J.‐F. 
Published: March 2003

Abstract• Experiments are presented that test the relative importance, during ontogeny, of stomatal control and leaf area expansion to optimum seasonal water use in pearl millet (Pennisetum glaucum). These parameters play a key role in the compromise between plant growth and water saving under unpredictable conditions of semiarid environments.• The response of growth and water use of crops to successive 15 d drought periods was measured under field conditions in Niger (West Africa).• From emergence to anthesis, biomass partitioning to stems and panicles depended strongly on leaf area development. Water use was linearly related to green leaf area duration in well watered plots, but was reduced proportionally more than green leaf area in drought‐affected plots. The relations of crop growth rate and transpiration efficiency to leaf area depended on ontogenetic changes in biomass partitioning.• In P. glaucum, stomata play a dominant role in reducing crop water use under preanthesis drought, although this control becomes negligible after anthesis because of ontogenetic decline in the range of stomatal conductance. The rate of leaf senescence after anthesis is not drought‐dependent.
Genetic variability of Pisolithus isolates associated with native hosts and exotic eucalyptus in the western Mediterranean region
Authors: Díez Jesús , Anta Berta , Manjón José Luis , Honrubia Mario 
Published: March 2003

Summary

• Genetic diversity and host specificity of Pisolithus is reported here in exotic (Eucalyptus) and native hosts in the western Mediterranean region.

• Polymorphism in the internal transcribed spacer (ITS) sequences of the nuclear rDNA of Pisolithus was analysed. Sequences for 17 isolates associated with native Mediterranean hosts and Eucalyptus were compared with those in the GenBank DNA database using distance and parsimony methods.

• Bootstrap analysis showed clustering of all Pisolithus isolates associated with Mediterranean hosts. The ITS sequences suggest the occurrence of several ecological species adapted to exploit different soil types (basic, acid and clayey slate‐derived soils), with specificity for particular indigenous hosts. Isolates from eucalypt plantations in Brazil, Kenya and the Mediterranean grouped together with eucalypt‐associated Australian isolates. Transfer to native hosts did not occur; the host specificity range of these exotic strains might prevent out‐competition and interbreeding with local species.

• Pisolithus spp. in eucalypt plantations in the Mediterranean basin are of Australian origin; the co‐introduction of the ectomycorrhizal fungi might explain the success of these exotic forest plantations.