bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification and localisation of glycoconjugates in the olfactory mucosa of the armadillo Chaetophractus villosus
Authors: FERRARI C. C. , CARMANCHAHI P. D. , ALDANA MARCOS H. J. , MUGNAINI M. T. , AFFANNI J. M. , PAZ D. A.
Published: March 2003

Conventional histochemistry and the binding patterns of 22 biotinylated lectins were examined for characterisation of glycoconjugates in the components of the olfactory mucosa of the armadillo Chaetophractus villosus. The mucous lining the olfactory epithelium showed binding sites for DSL, WGA, STL, LEL, PHA‐E and JAC. Only the basilar processes of the supporting cells stained for Con‐A and S‐Con A. The olfactory receptor neurons stained with LEL, LCA, Con A, S‐Con A, JAC and PNA. The layer of basal cells did not react with any of the lectins studied. Bowman's glands in the lamina propria showed subpopulations of acinar cells reacting with SBA, S‐WGA, WGA, STL, Con A, PSA, PNA, SJA, VVA, JAC and S‐Con A, but in our optical studies with lectins we were unable to differentiate between mucous and serous cells in the way that is possible on electron microscopy. The ducts of Bowman's glands were labelled with S‐WGA, STL, LEL, PHA‐E, BSL‐I and JAC. This histochemical study on the glycoconjugates of the olfactory mucosa in the order Xenarthra provides a basis for further experimental investigations.
The impact of mammalian reproduction on cancellous bone architecture
Authors: SHAHTAHERI S. M. , AARON J. E. , JOHNSON D. R. , PAXTON S. K.
Published: March 2003

Pregnancy and lactation make demands on maternal calcium homeostasis which may affect bone strength. Recently, changes in cancellous architecture have been described in iliac crest bone biopsies from normal pregnant women but the rarity of such human material means an animal model is essential. The microanatomy of cancellous bone was compared in uniparous and multiparous rats using undecalcified histological sections of lumbar and caudal vertebrae and also proximal femora. An automated trabecular analysis system (TAS) measured a comprehensive range of structural variables including the trabecular number, connectivity and width. In the first pregnancy cycle an early stimulation of bone formation (which quadrupled at some sites) was indicated by an increase in the skeletal uptake and spacing of double calcein labels and the immediate generation of thicker more numerous and interconnected trabeculae. A 40% increase in cancellous bone volume was observed in the lumbar spine in comparison with age‐matched virgin controls. In contrast, a rapid succession of 3 pregnancy cycles (including lactation) culminated in cancellous atrophy of 15% at the same site, with a loss in trabecular number ranging from 20% (caudal vertebra) to 30% (lumbar vertebrae). In comparison, the proximal femur lost 40% of its struts but, nevertheless, uniquely sustained its cancellous bone volume. When lactation was excluded the number of struts lost was halved although trabecular thinning then took place which was sufficient to maintain the previous 15% deficit in bone volume. It was concluded that a single pregnancy strengthens the cancellous component of the maternal skeleton while a quick succession of pregnancies weakens it. Lactation influences the pattern of bone loss but not its amount.
Postnatal development of intestinal endocrine cell populations in the water buffalo
Authors: LUCINI CARLA , DE GIROLAMO PAOLO , COPPOLA LUIGI , PAINO GIUSEPPE , CASTALDO LUCIANA
Published: March 2003

The frequency and distribution of 11 endocrine cell populations were studied in the intestine of differently aged buffalo, grouped on the basis of diet: 2‐d‐olds (suckling), 5‐mo‐olds (weaning) and 5‐y‐olds (ruminant adult diet). The endocrine cell populations were identified immunocytochemically using antisera against 5‐hydroxytryptamine (5‐HT), somatostatin, gastrin, cholecystokinin (CCK), COOH‐terminal octapeptide of gastrin/CCK, neurotensin, motilin, gastric inhibitory polypeptide (GIP), secretin, glucagon/glicentin (GLU/GLI) and polypeptide YY (PYY). In adult buffalos the regional distribution of endocrine cells is similar to that of other adult ruminants. During postnatal development, these cell types showed the following changes in their frequency and distribution: (1) 5‐HT, neurotensin and gastrin/CCK immunoreactive cells (i.c.) showed a decrease in frequency with age; (2) somatostatin i.c. frequency remained stable with age; (3) motilin, GIP, secretin and CCK i.c. showed a slight increase in frequency with age; (4) GLU/GLI and PYY i.c. decreased in frequency with age in the small intestine, caecum and proximal colon and an increase in frequency in the rectum. It was hypothesised that the endocrine cell types, whose presence and localisation is substantially stable in all examined ages, probably contain substances that are strictly necessary for intestinal function. In contrast the hormones contained in the cell populations that decreased with age, are probably involved in physiological needs during the milk and weaning diet or play a role in intestinal growth.
Ultrastructural features of goat oviductal secretory cells at follicular and luteal phases of the oestrous cycle
Authors: ABE HIROYUKI , ONODERA MASAKAZU , SUGAWARA SHICHIRO , SATOH TAKESHI , HOSHI HIROYOSHI
Published: March 2003

The aim of the present study was to investigate the ultrastructure of secretory cells in the various regions of the goat oviduct during the follicular and luteal phases of the oestrous cycle. During the follicular phase in the fimbriae, the secretory cells contained small secretory granules with electron‐dense matrices. In the luteal phase, the secretory granules disappeared and cytoplasmic protrusions, extending beyond the luminal border of the ciliated cells and often containing the nucleus, were predominant. During the follicular phase in ampullary secretory cells, numerous secretory granules with moderately electron‐dense matrices were present in the supranuclear cytoplasm and exocytosis of secretory granules was observed. The number of secretory granules was dramatically reduced in the ampullary secretory cells at the luteal phase. Conspicuous cytoplasmic protrusions of secretory cells were observed similar to those of the fimbrial epithelium. Isthmic cells were almost free of secretory granules and lysosome‐like bodies were found both at the follicular and luteal phases. In conclusion, our ultrastructural observations of goat oviduct revealed marked cyclic changes in the ultrastructural features of secretory cells and the ultrastructural features and the numbers of secretory granules were distinctive for each particular segment.
The vomeronasal organ of the South American armadillo Chaetophractus villosus (Xenarthra, Mammalia): anatomy, histology and ultrastructure
Authors: CARMANCHAHI P. D. , ALDANA MARCOS H. J. , FERRARI C. C. , AFFANNI J. M.
Published: March 2003

The vomeronasal organ (VNO) is a chemoreceptive structure that has not been extensively studied in the Xenarthran order. Tissue samples from the VNO of the armadillo Chaetophractus villosus were prepared for light and electron microscopy. The VNO is located in the anterior part of the base of the nasal septum. It is tubular in shape, ∼ 18 mm in length and opens in the rostral region of the nasal cavity and with a blind caudal end. Its lumen is lined by sensory (SE) and nonsensory (NSE) epithelium. The SE shows sensory, supporting and basal cells whereas the NSE contains ciliated and nonciliated secretory cells and basal cells. At the ultrastructural level, the sensory cells appear as bipolar neurons with conspicuous microvilli on their free surface. The supporting cells of the SE contain numerous membrane‐bound vesicles in their apical regions. A peculiar feature not found in other mammals, is the presence of concentric whorls of RER cisterns frequently observed in their basal expansions. Infiltrating plasma cells can be detected in the SE basal region close to the dorsal junctional area. This region also exhibits an unusual type of basal cell, probably responsible for the generation of new vomeronasal receptor neurons. The ciliated NSE cells exhibit numerous ovoids or irregularly shaped membranous protrusions projecting from the plasma membrane of the cilia. As far as we know, this is the first study reporting the presence of this feature in ciliated NSE cells. The nonciliated cells are characterised by scarce large secretory granules and apical microvilli. The vomeronasal glands are compound‐branched tubuloacinar glands with serous acinar cells. Four types of secretory granules are present. The ducts of these glands reach the lumen in the dorsolateral region between the NSE and SE. Hypolemmal nerve terminals were observed contacting secretory cells. Fenestrated and nonfenestrated capillaries constitute the vascular supply to these glands. Plasma cells, intimately associated with acinar cells, were frequently observed.
Regression of blood vessels in the ventral velum of Xenopus laevis Daudin during metamorphosis: light microscopic and transmission electron microscopic study
Authors: BARTEL H. , LAMETSCHWANDTNER A.
Published: March 2003

Structural changes of the ventral velum of Xenopus laevis tadpoles from late prometamorphosis (stage 58) to the height of metamorphic climax (stage 62) were examined by light and transmission electron microscopy. Special emphasis was given to the blood vessel regression. Early changes of velar capillaries were formation of luminal and abluminal endothelial cell processes, vacuolation, and cytoplasmic and nuclear chromatin condensation. At the height of metamorphic climax, transmission electron microscopy revealed apoptotic endothelial cells with nuclear condensation and fragmentation, intraluminal bulging of rounded endothelial cells which narrowed or even plugged the capillary, and different stages of endothelial cell detachment (‘shedding’) into the vessel lumen. These changes explain the ‘miniaturisation’ of the velar microvascular bed as well as the typical features found in resin‐casts of regressing velar vessels which have been observed in a previous scanning electron microscopy study of the ventral velum.
A comparative analysis of the differential spatial and temporal distributions of the large (aggrecan, versican) and small (decorin, biglycan, fibromodulin) proteoglycans of the intervertebral disc
Authors: MELROSE JAMES , GHOSH PETER , TAYLOR THOMAS K. F.
Published: March 2003

This study provides a comparative analysis of the temporal and spatial distribution of 5 intervertebral disc (IVD) proteoglycans (PGs) in sheep. The main PGs in the 2 and 10 y old sheep groups were polydisperse chondroitin sulphate and keratan sulphate substituted species. Their proportions did not differ markedly either with spinal level or disc zone. In contrast, the fetal discs contained 2 slow migrating (by composite agarose polyacrylamide gel electrophoresis, CAPAGE), relatively monodisperse chondroitin sulphate‐rich aggrecan species which were also identified by monoclonal antibody 7‐D‐4 to an atypical chondroitin sulphate isomer presentation previously found in chick limb bud, and shark cartilage. The main small PG detectable in the fetal discs was biglycan, whereas decorin predominated in the 2 and 10 y old IVD samples; its levels were highest in the outer annulus fibrosus (AF). Versican was most abundant in the AF of the fetal sheep group; it was significantly less abundant in the 2 and 10 y old groups. Furthermore, versican was immunolocalised between adjacent layers of annular lamellae suggesting that it may have some role in the provision of the viscoelastic properties to this tissue. Versican was also diffusely distributed throughout the nucleus pulposus of fetal IVDs, and its levels were significantly lower in adult IVD specimens. This is the first study to identify versican in ovine IVD tissue sections and confirmed an earlier study which demonstrated that ovine IVD cells synthesised versican in culture (Melrose et al. 2000). The variable distribution of the PGs identified in this study provides further evidence of differences in phenotypic expression of IVD cell populations during growth and development and further demonstrates the complexity of the PGs in this heterogeneous but intricately organised connective tissue.
Evidence of a hypermineralised calcified fibrocartilage on the human femoral neck and lesser trochanter
Authors: SHEA J. E. , VAJDA E. G. , BLOEBAUM R. D.
Published: March 2003

Femoral neck fractures are a major cause of morbidity and mortality in elderly humans. In addition to the age‐related loss of cancellous bone, changes to the microstructure and morphology of the metaphyseal cortex may be a contributing factor in osteoporotic hip fractures. Recent investigations have identified a hypermineralised tissue on the neck of the femur and trochanteric region that increases in fractional area with advancing age in both males (Boyce & Bloebaum, 1993) and females (Vajda & Bloebaum, 1999). The aim of this study was to determine if the hypermineralised tissue previously observed on the proximal femur is calcified fibrocartilage. Regional variations in the fractional area of hypermineralised tissue, cortical bone, and porosity of the cortical bone along the neck of the femur and lesser trochanter were also quantified. Comparison of back scattered electron and light microscope images of the same area show that regions of hypermineralised tissue correlate with the regions of calcified fibrocartilage from tendon and capsular insertions. The hypermineralised tissue and calcified fibrocartilage had similar morphological features such as the interdigitations of the calcified fibrocartilage into the bone, lacunar spaces, and distinctly shaped pores adjacent to the 2 tissues. Regions of the neck that did not contain insertions were covered with periosteum. There were no regional differences (P > 0.05) on the superior and inferior femoral neck in terms of the percentage area of hypermineralised calcified fibrocartilage, cortical bone, or cortical bone porosity. The lesser trochanter exhibited regional differences in the fractional area of hypermineralised calcified fibrocartilage (P = 0.007) and cortical bone (P = 0.007) but not porosity of the cortical bone (P > 0.05). The effects of calcified fibrocartilage on femoral neck periosteal expansion, repair, and mechanics are unknown, but may play a role in osteoporotic fractures and intracapsular fracture healing.
Occurrence and structure of epipharyngeal pouches in bears (Ursidae)
Authors: WEISSENGRUBER G. E. , FORSTENPOINTNER G. , KÜBBER‐HEISS A. , RIEDELBERGER K. , SCHWAMMER H. , GANZBERGER K.
Published: March 2003

The infrequent mention of epipharyngeal pouches occurring in some species of bears indicates the scarcity of morphological and functional knowledge about these structures. In order to provide precise morphological data on the structure of these remarkable formations and to verify their taxonomic utility, the pharyngeal regions of 1 spectacled bear and 3 brown bears were examined. All these individuals possessed epipharyngeal pouches, which are tubular, blind‐ending outpouchings of the caudodorsal pharyngeal wall equipped with respiratory epithelium and a thick layer of elastic fibres. While the spectacled bear and Ursus arctos syriacus possessed a single pouch on the caudodorsal wall of the nasopharynx, in Ursus arctos and Ursus arctos beringianus 2 unequally sized pouches were present. Two additional sacs of smaller size, representing outpouchings of the lateral pharyngeal wall, occurred in the spectacled bear. These findings prove epipharyngeal pouches to be constant and unique morphological features of the family Ursidae, the anatomical features suggesting involvement in the respiratory system most probably in important aspects of ursid phonation. This is the first description of epipharyngeal pouches in the spectacled bear.
Evolution and development of teeth
Authors: McCOLLUM MELANIE , SHARPE PAUL T.
Published: March 2003

abstract

Teeth as a feeding mechanism in an oral cavity (mouth) are functionally and locationally linked with jaws. In fossils, teeth found in the oral cavity are usually linked with jaws, although mineralised structures with the same histology as teeth are known in fossils before jaws appeared. Denticles in the skin occur in both fossil and extant fish. Pharyngeal denticles also occur in both extant and fossil gnathostomes but in only a few fossil agnathans (thelodonts). Complex structures with dentine and enamel have been described in the earliest jawless vertebrates, conodonts. Such fossils have been used to suggest that teeth and jaws have evolved and developed independently. Our understanding of the developmental biology of mammalian tooth development has increased greatly in the last few years to a point where we now understand some of the basic genetic interactions controlling tooth initiation, morphogenesis and patterning. The aim of this review is to see what this developmental information can reveal about evolution of the dentition.
Soluble flt and the angiopoietins in the development and regulation of placental vasculature
Authors: Charnock‐Jones D. S.
Published: March 2003

One of the key roles of the placenta is to mediate exchange of oxygen, nutrients and waste products between the maternal and fetal circulations. While some nutrients are actively taken up, oxygen is passively transported (i.e. it moves down a simple concentration gradient). To ensure an adequate supply as gestation progresses the vascular structures in the human placenta remodel to facilitate this transfer. Under conditions where oxygen is limited, at high altitude for example, these adaptations become more pronounced. In placentae obtained from high altitude the mean diameter of vessels is increased and the number of perivascular cells (pericytes) is reduced. Pericytes play an important role in modulating endothelial cell function and in their absence the endothelial cells are sensitive to growth factor withdrawal. The vascular remodelling that occurs in normal pregnancy is in part mediated by soluble factors (some produced by pericytes) and the level of these may in turn be regulated by local oxygen tension. We have shown that the mRNAs encoding both angiopoietins are present in the placenta and both are regulated by local pO2. Ang‐2 mRNA transcription is increased under reduced oxygen and the stability of Ang‐1 mRNA is reduced under similar conditions. Thus the ratio of mRNAs encoding these antagonistic factors changes (in favour of Ang‐2) in the placenta in response to a reduction in pO2. The adaptations seen in the placenta and the mechanism by which they are achieved may be generally applicable.
Angiogenic activity in embryonic chick lung
Authors: Hanton R. , McLachlan J. C.
Published: March 2003

Normal and pathological formation of blood vessels is of considerable interest both in terms of basic scientific processes and clinical applications. The presence of Flk‐1 mRNA positive cells has been detected in the embryonic lung in previous studies. Flk‐1 mRNA codes for vascular endothelial growth factor (VEGF) receptors. Bioassays offer advantages over molecular localisation techniques in that the presence of active processed forms of the molecules can be revealed, rather than nonprocessed forms, or nontranslated messages. In this study it is shown that developing chick lung tissue from 9 d and 10 d old embryos produces an angiogenic activity when incubated on chick chorioallantoic membrane (CAM). Significant angiogenic activity is not detected when 7 d and 8 d old embryonic lung tissue is assessed by the same bioassay. When angiogenic activity induced by lung grafts taken from distal regions of the 10 d old lung is compared with angiogenic activity induced by lung grafts taken from proximal regions of the10 d old lung, no significant difference is found. The evidence suggests that embryonic chick lung is producing a functional angiogenic endothelial cell growth factor (thought to be VEGF) from at least as early as its 9th day of development.
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

The 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

The 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

We 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

Potted 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

In 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

summary

The 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

Development 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

summary

A 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

summary

Copper 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.
A gnotobiotic culture system with oak microcuttings to study specific effects of mycobionts on plant morphology before, and in the early phase of, ectomycorrhiza formation by Paxillus involutus and Piloderma croceum
Authors: HERRMANN S. , MUNCH J.‐C. , BUSCOT F.
Published: March 2003

Homogeneously developed oak (Quercus robur L.) microcuttings were challenged in a Petri‐dish system with the mycobionts Piloderma croceum J. Erikss. & Hjortst. and Paxillus involutus (Batsch) Fr. Non‐destructive observations over 10 wk followed by d. wt measurements at the end of the assays served to precisely characterize root and shoot development, dynamics of mycorrhizal colonization and morphological ratio. In the system, plant development, and especially root morphogenesis, had more similarities to those of stump cuttings or of older seedlings than to those of 3‐month‐old seedlings. Whereas Paxillus involutus displayed early mycorrhizal colonization and had no significant morphological effects on the host Piloderma croceum modified markedly the entire plant development before a delayed mycorrhiza formation. The latter mycobiont stimulated elongation and production of the lateral root system and also increased the leaf surface. However, no corresponding weight increases were noted, which was reflected by significant increase of both specific root length and specific leaf area. These differential effects are discussed in relation to data concerning carbon requirement and auxin production of the mycobionts. The developed system was shown to be highly suitable for comparative studies with diverse mycobionts on recognition and physiological balance between partners before, and in the early stage of, formation of mycorrhizas.
Effects of u.v.‐B radiation on epicuticular wax production and chemical composition of four Picea species
Authors: GORDON D. C. , PERCY K. E. , RIDING R. T.
Published: March 2003

Two‐yr‐old Norway (Picea abies (L.) Karst.), red (P. rubens Sarg.), black (P. mariana (Mill.) B.S.P.) and white (P. glauca (Moench.) Voss) spruce seedlings were exposed from bud break for 35 or 63 d (4·5 h irradiance d−1) to a gradient of biologically effective u.v.‐B radiation (λ=280–315 nm) ranging from 0·61 kJ m−2 d−1 to 5·99 kJ m−2 d−1. No visible symptoms of u.v.‐B injury were observed. Epicuticular wax production was not affected by needle exposure to increasing u.v.‐B irradiance. Seven constituent classes were resolved by GC and confirmed by GC–MS in wax recovered from needles of the four species. Wax composition of Norway, black and red spruce was altered following needle exposure to increasing u.v.‐B dose. White spruce wax composition was unaffected. Direction and magnitude of wax composition response was species‐dependent. The proportion of nonacosane diols on Norway spruce needles increased (P<0·05) whereas that of alkyl esters decreased with increasing u.v.‐B dose. The proportion of fatty acids in black spruce needle wax increased (P<0·05), and that of estolides (GC‐identified) in red spruce needle wax increased (P<0·05) with increasing u.v.‐B dose. Changes in wax chemical composition reported were induced following to daily, 4‐h duration exposures of needles to u.v.‐B centred on 1200 hours. Affected variables exhibited a continuum of response. The highest dose applied was within the range of measured or predicted increases in mid‐northern latitudes. Such changes in conifer needle epicuticular wax chemical composition might result in increased seedling sensitivity to the changing atmospheric environment, especially from co‐exposure to tropospheric ozone in mid‐northern latitudes where much of Canada's productive forest is located.
Ecotypic adaptation in Austrocedrus chilensis in cuticular hydrocarbon composition
Authors: DODD RICHARD S. , RAFII ZARA A. , POWER ARIEL B.
Published: March 2003

An homologous series of hydrocarbons ranging from C21 to C37 (was detected in foliar cuticular waxes of Austrocedrus chilensis (D. Don) Pic.‐Ser. & Bizz., by gas chromatography. Qualitatively, the chromatograms were similar for all individuals sampled from 29 natural populations in Chile and Argentina, showing C33 and C35 alkanes to be dominant. Quantitatively, the chromatograms varied significantly among populations. Multivariate analyses showed that arid zone populations from mediterranean Chile and the Patagonian steppe were different from one another and were distinct from mesic populations close to the Valdivian rainforest vegetation zone. Mediterranean Chilean populations were characterized by higher concentrations of the longer carbon‐chain alkanes, but retained equal amounts of shorter‐chain homologues as the mesic populations. A greater variation in chain lengths and higher concentrations of longer carbon chains in the mediterranean populations is consistent with a model for the adaptation to reduced cuticular permeability. Partial Mantel matrix tests revealed significant climatic and inter‐population distance effects with taxonomic distances based on multivariate and univariate hydrocarbon data. Annual rainfall was overall the most significant factor, particularly in regressions with the shorter‐chain hydrocarbons. Annual mean temperature was most significant for the longer‐chain hydrocarbons. This suggests, on the one hand, ecogenic adaptation to both temperature and precipitation of cuticular hydrocarbon composition, and, on the other hand, a weaker, but important effect of gene flow in determining hydrocarbon composition in this species. The northernmost populations at San Felipe and San Gabriel were the most distinctive. This could result from the effects of random changes in allele frequencies and/or to founder effects in isolated and small populations. These populations show some East‐Andean affinities presumably due to historic migration patterns.
Regulation of plant nitrate assimilation: from ecophysiology to brain proteins
Authors: MacKINTOSH CAROL
Published: March 2003

Nitrogenous inorganic compounds impact plants as nutrients, signals and toxins. We are dissecting a regulatory network that controls nitrate assimilation at the level of nitrate reductase (NR) activity. The identification of protein kinase cascades, protein phosphatases and 14‐3‐3 proteins as regulators of NR are giving clues about how plants sense their nutrient availability, and use the information to signal changes in their metabolism and developmental strategies to cope with supplies. We hope that understanding these controls might lead to the design of transgenic plants with deregulated signalling networks, which would make them more efficient in using nitrogen fertilizers, and improving quality and yield of crops. There are circumstantial indications that gaseous anthropogenic nitrogenous emissions might also have complex regulatory influences on plant growth and development.
Spatial distribution of ectomycorrhizas and arbuscular mycorrhizas in Korup National Park rain forest, Cameroon, in relation to edaphic parameters
Authors: MOYERSOEN B. , FITTER A. H. , ALEXANDER I. J.
Published: March 2003

The frequent co‐occurrence of ectomycorrhizas and arbuscular mycorrhizas in the same ecosystem raises the question about how two functionally different mycorrhizal associations exploit a spatially heterogeneous habitat. Horizontal (in plots along a transect of 3750 m crossing forest types of low and high abundance of ectomycorrhizal (ECM) host species) and vertical (across profiles of litter and 0–5 cm, 10–15 cm, 25–35 cm soil layers) distribution of ectomycorrhizas and arbuscular mycorrhizas in relation to edaphic parameters (pH, moisture, total carbon, total nitrogen and extractable‐phosphorus concentration) was compared in Korup National Park rain forest, to test the hypothesis that the two types of mycorrhiza exploit different niches. No pattern was observed in either ECM or arbuscular mycorrhizal (AM) fractional colonization with depth in the profile even though most of the variation in soil parameters was vertical. Only local (between monoliths within plots) horizontal differences were found in soil parameters. By contrast, horizontal differences in fractional colonization were found between forest types, and between monoliths, for ectomycorrhizas but only between monoliths for arbuscular mycorrhizas. The lack of a clear relationship between both horizontal and vertical distribution of ECM and AM fractional colonization and soil parameters suggests that both fungal groups are equally able to colonize the same niche, at the scale of our experiment. By contrast, a negative relationship was found between AM and ECM fractional colonization in the litter and 0–5 cm and 10–15 cm soil layers. This, in addition to the more heterogeneous horizontal distribution of arbuscular mycorrhizas in forest areas dominated by ectomycorrhizas and a patchy vertical distribution of the former as opposed to a more coherent distribution of the latter, suggests that both types of mycorrhizal fungi compete for the same niche. The co‐occurrence of ectomycorrhizas and arbuscular mycorrhizas might be explained by differences between ECM and AM hosts and fungi in their colonizing abilities.
Influence of epiphytic micro‐organisms on leaf wettability: wetting of the upper leaf surface of Juglans regia and of model surfaces in relation to colonization by micro‐organisms
Authors: KNOLL D. , SCHREIBER L.
Published: March 2003

Wetting of the upper leaf surface of Juglans regia L. and of model surfaces colonized by epiphytic micro‐organisms was investigated by measuring contact angles of aqueous solutions buffered at different pH values. During June to October 1995, contact angles of aqueous solutions on the leaf surface of J. regia decreased by angles ranging from 12° (low pH values) to 25° at high pH values. At the end of this vegetation period, wetting was strongly dependent on pH showing significantly lower contact angles with alkaline solutions (pH 9·0) than with acidic solutions (pH 3·0). Contact angle titration measured angles on the leaf surface as a function of the pH of buffered aqueous solutions, covering a pH range from 3·0 to 11·0. Titration curves revealed inflection points around 7·5, indicating the existence of ionizable carboxylic groups at the interface of the phylloplane. Altered leaf‐surface wetting properties observed on the intact leaf surface could be simulated in model experiments by measuring contact angles on artificial surfaces colonized by Pseudomonas fluorescens and by epiphytic micro‐organisms isolated from the phylloplane of J. regia. Strong evidence is provided that interfacial carboxylic groups derive from epiphytic micro‐organisms present on the phylloplane. Results suggest that the age‐dependent increase in, and pH dependence of, wetting as leaves mature are related to the presence of epiphytic micro‐organisms on the phylloplane. Ecological consequences of increased leaf‐surface wetting, concerning the structure of the leaf surface as a microhabitat for epiphytic micro‐organisms, are discussed.