The tandem PDZ domains of syntenin promote cell invasion

Syntenin is a tandem PDZ protein that has recently been shown to be overexpressed in several cancer cells and tissues, and that might play an active role in tumor cell invasion and metastasis. Here we show that overexpression of the tandem PDZ domains of syntenin in non-invasive cells is necessary and sufficient to stimulate these cells to invade a collagen I matrix, and this effect can be regulated by ligand binding to the PDZ domains. Furthermore, we show that syntenin-induced invasion requires signaling through ras, rho and PI3K/MAPK signaling pathways and involves changes in cell-cell adhesion. Inversely, when we used RNA interference to inhibit syntenin expression in different invasive cancer cell lines, we observed a drastically decreased ability of these cells to migrate and invade into collagen type I or Matrigel. RNAi-treated cells also show increased cell aggregation, indicating that syntenin is important for cell-cell adhesion in epithelial cells. Together, these results suggest that downregulation of syntenin by RNA interference could provide a means of inhibiting tumor invasion and possibly metastasis in different cancers, and point to syntenin as a potential cancer biomarker and drug target.     

IL-17 promotes bone erosion in murine collagen-induced arthritis through loss of the receptor activator of NF-kappa B ligand/osteoprotegerin balance

IL-17 is a T cell-derived proinflammatory cytokine in experimental arthritis and is a stimulator of osteoclastogenesis in vitro. In this study, we report the effects of IL-17 overexpression (AdIL-17) in the knee joint of type II collagen-immunized mice on bone erosion and synovial receptor activator of NF-kappa B ligand (RANKL)/receptor activator of NF-kappa B/osteoprotegerin (OPG) expression. Local IL-17 promoted osteoclastic bone destruction, which was accompanied with marked tartrate-resistant acid phosphatase activity at sites of bone erosion in cortical, subchondral, and trabecular bone. Accelerated expression of RANKL and its receptor, receptor activator of NF-kappa B, was found in the synovial infiltrate and at sites of focal bone erosion, using specific immunohistochemistry. Interestingly, AdIL-17 not only enhanced RANKL expression but also strongly up-regulated the RANKL/OPG ratio in the synovium. Comparison of arthritic mice from the AdIL-17 collagen-induced arthritis group with full-blown collagen-arthritic mice having similar clinical scores for joint inflammation revealed lower RANKL/OPG ratio and tartrate-resistant acid phosphatase activity in the latter group. Interestingly, systemic OPG treatment prevented joint damage induced by local AdIL-17 gene transfer in type II collagen-immunized mice. These findings suggest T cell IL-17 to be an important inducer of RANKL expression leading to loss of the RANKL/OPG balance, stimulating osteoclastogenesis and bone erosion in arthritis.     

Faunal composition of geometrid moths changes with altitude in an Andean montane rain forest

Aim The objective of this study was to describe and interpret the changes in faunal composition in the moth family Geometridae (Lepidoptera) along a small‐scale elevational gradient in a tropical montane rain forest. This gradient was compared with a large‐scale latitudinal gradient in Europe. Location Investigations were carried out in the province Zamora‐Chinchipe in southern Ecuador along a gradient ranging from 1040 to 2677 m above sea level at twenty‐two sites. Methods Moths were sampled with light‐traps in three field periods in 1999 and 2000 and subsequently sorted and determined to species or morphospecies. Results We analysed 13,938 specimens representing 1010 species of geometrid moths. The proportional contribution of subtaxa to the local geometrid fauna changes along the elevational gradient at all systematic levels considered. While proportions of species of the subfamilies Ennominae, Sterrhinae and Geometrinae significantly decrease, the proportion of Larentiinae increases with increasing altitude. Changes also occur within the subfamilies Ennominae and Larentiinae. The host–plant specialist ennomine tribes Cassymini, Macariini and Palyadini completely vanish, and the proportion of the tribe Boarmiini decreases at high altitudes. In contrast, the remaining tribes (mostly comprising polyphagous species) either do not show proportional changes (Azelinini, Nacophorini, Nephodiini, Ourapterygini) or even increase (Caberini, ‘Cratoptera group’). Within Larentiinae, the species proportion of the genus Eois decreases, whereas concomitantly the proportion of Eupithecia increases. There is a remarkable similarity between the altitudinal patterns in Ecuador and those found along the latitudinal gradient in Europe. Main conclusions Species of the subfamily Larentiinae seem to be particularly well‐adapted to harsh environmental conditions, towards both high altitudes and latitudes. They might disproportionately profit from lower predation at higher altitudes. Many changes in the faunal composition can be explained by expected host–plant requirements of the species involved. Our results show that diversity estimates based on taxon ratios which are assumed to be constant must be regarded with caution because such ratios can change rapidly along environmental gradients.     

Palynological variation in balsaminoid ericales. I. Marcgraviaceae

BACKGROUND AND AIMS: Marcgraviaceae are a rather small family of seven genera and approx. 130 neotropical species. This study aims to present a detailed palynological survey of the family in order to comment on the intrafamily relationships and possible correlations with pollinators. METHODS: In total, 119 specimens representing 67 species and all genera are observed using light microscopy and scanning electron microscopy. Furthermore, eight species from five genera are studied with transmission electron microscopy. KEY RESULTS: Our results show that pollen grains of Marcgraviaceae are small (20-35 microm), have three equatorial apertures, granules on the colpus membrane, oblate spheroidal to prolate spheroidal shapes, mainly psilate to perforate ornamentations, and lalongate colpus-shaped thinnings at the inner layer of the exine, and show the presence of orbicules. Based on our fragmentary knowledge of the pollination biology of the family, there are no clear correlations between pollinators and pollen features. CONCLUSIONS: The genus Marcgravia has a high percentage of reticulate sexine patterns and a relatively thin nexine. Sarcopera can be defined by the presence of an oblate spheroidal to even suboblate shape, while Ruyschia and Souroubea typically show prolate spheroidal to subprolate pollen grains. The presence of a thick foot layer in the pollen wall is characteristic of the genera Norantea, Sarcopera and Schwartzia. Pollen features that are taxonomically useful within the family are the shape, sexine sculpturing, and ultrastructure of the pollen wall.     

LDL transcytosis by protein membrane diffusion

Endothelial cell (EC) cultures of different, selected vascular beds and/or organs were screened for receptor-mediated transport of proteins with a semipermeable filter assay. In SVEC4-10 cells, a mouse lymphoid endothelial cell line, orosomucoid, albumin, insulin and LDL were transcytosed from the apical (luminal) to basal (abluminal) side by a receptor-mediated pathway. Specific LDL transcytosis involved transport of intact LDL. A pathway of degradation of LDL and basal release involved vesicles in transport to lysosomes and amino acid merocrine secretion. This newly described transcellular passage of LDL via lysosomes, as well as the standard pathway, were reduced to 70% by PEG(50)-cholesterol (PEG-Chol). Combined results of temperature-dependence analysis and PEG(50)-cholesterol sensitivity show that two pathways contribute to general LDL transcellular passage. We suggest a mechanism of domain hopping by protein membrane diffusion of receptors as the pathway for intact LDL delivery. Based on theoretical considerations we propose that active transport by protein membrane diffusion can be facilitated by an organizational structure of lipid microdomains and polar cellular organization.     

Scavenger receptor class B type I reduces cholesterol absorption in cultured enterocyte CaCo-2 cells

Scavenger receptor class B type I (SR-BI) mediates selective uptake of cholesteryl esters from HDL as well as efflux of cellular free cholesterol to HDL. It is unclear whether the receptor is involved in intestinal cholesterol absorption. We addressed this issue by studying [3H]cholesterol flux in differentiated CaCo-2 cells incubated at their apical side with mixed taurocholate/phosphatidylcholine/cholesterol micelles. Biotinylation and HDL binding experiments showed predominant apical expression of endogenous and overexpressed SR-BI. Mixed micellar cholesterol saturation affected the magnitude and direction of cholesterol flux with significant net uptake only from supersaturated micelles and net efflux from unsaturated micelles. Incubation with micelles that depleted cellular cholesterol resulted in a decrease of SR-BI protein, whereas incubation with cholesterol-loading micelles resulted in a significant increase of SR-BI protein. Apical cholesterol uptake by CaCo-2 cells was increased in the presence of a SR-BI-blocking antibody and by partial inhibition of SR-BI expression with small inhibitory RNA. Adenovirus-mediated overexpression of apical SR-BI did not affect cholesterol uptake but stimulated apical cholesterol efflux, even to supersaturated mixed micelles. Partial inhibition of SR-BI with small inhibitory RNA reduced apical cholesterol efflux. Our data argue against a direct role for SR-BI in micellar cholesterol uptake. However, SR-BI might be involved in cholesterol absorption by facilitating cholesterol efflux to micelles.     

First record of the brachiopod Lingulella waptaensis with pedicle from the Middle Cambrian Burgess Shale

Pettersson Stolk, S., Holmer, L. E. and Caron, J ‐B. 2010. First record of the brachiopod Lingulella waptaensis with pedicle from the Middle Cambrian Burgess Shale. —Acta Zoologica (Stockholm) 91 : 150–162 The organophosphatic shells of linguloid brachiopods are a common component of normal Cambrian–Ordovician shelly assemblages. Preservation of linguloid soft‐part anatomy, however, is extremely rare, and restricted to a few species in Lower Cambrian Konservat Lagerstätten. Such remarkable occurrences provide unique insights into the biology and ecology of early linguloids that are not available from the study of shells alone. Based on its shells, Lingulella waptaensis Walcott, was originally described in 1924 from the Middle Cambrian Burgess Shale but despite the widespread occurrence of soft‐part preservation associated with fossils from the same levels, no preserved soft parts have been reported. Lingulella waptaensis is restudied herein based on 396 specimens collected by Royal Ontario Museum field parties from the Greater Phyllopod Bed (Walcott Quarry Shale Member, British Columbia). The new specimens, including three with exceptional preservation of the pedicle, were collected in situ in discrete obrution beds. Census counts show that L. waptaensis is rare but recurrent in the Greater Phyllopod Bed, suggesting that this species might have been generalist. The wrinkled pedicle protruded posteriorly between the valves, was composed of a central coelomic space, and was slender and flexible enough to be tightly folded, suggesting a thin chitinous cuticle and underlying muscular layers. The nearly circular shell and the long, slender and highly flexible pedicle suggest that L. waptaensis lived epifaunally, probably attached to the substrate. Vertical cross‐sections of the shells show that L. waptaensis possessed a virgose secondary layer, which has previously only been known from Devonian to Recent members of the Family Lingulidae.     

Dinitrogen fixation in white clover grown in pure stand and mixture with ryegrass estimated by the immobilized 15N isotope dilution method

Dinitrogen fixation in white clover (Trifolium repens L.) grown in pure stand and mixture with perennial ryegrass (Lolium perenne L.) was determined in the field using ¹⁵N isotope dilution and harvest of the shoots. The apparent transfer of clover N to perennial ryegrass was simultaneously assessed. The soil was labelled either by immobilizing ¹⁵N in organic matter prior to establishment of the sward or by using the conventional labelling procedure in which ¹⁵N fertilizer is added after sward establishment. Immobilization of ¹⁵N in the soil organic matter has not previously been used in studies of N₂ fixation in grass/clover pastures. However, this approach was a successful means of labelling, since the ¹⁵N enrichment only declined at a very slow rate during the experiment. After the second production year only 10–16% of the applied ¹⁵N was recovered in the harvested herbage. The two labelling methods gave, nonetheless, a similar estimate of the percentage of clover N derived from N₂ fixation. In pure stand clover, 75–94% of the N was derived from N₂ fixation and in the mixture 85–97%. The dry matter yield of the clover in mixture as percentage of total dry matter yield was relatively high and increased from 59% in the first to 65% in the second production year. The average daily N₂ fixation rate in the mixture-grown clover varied from less than 0.5 kg N ha⁻¹ day⁻¹ in autumn to more than 2.6 kg N ha⁻¹ day⁻¹ in June. For clover in pure stand the average N₂ fixation rate was greater and varied between 0.5 and 3.3 kg N ha⁻¹ day⁻¹, but with the same seasonal pattern as for clover in mixture. The amount of N fixed in the mixture was 23, 187 and 177 kg N ha⁻¹ in the seeding, first and second production year, respectively, whereas pure stand clover fixed 28, 262 and 211 kg N ha⁻¹ in the three years. The apparent transfer of clover N to grass was negligible in the seeding year, but clover N deposited in the rhizosphere or released by turnover of stolons, roots and nodules, contributed 19 and 28 kg N ha⁻¹ to the grass in the first and second production year, respectively. This revised version was published online in June 2006 with corrections to the Cover Date.     

Root traits as tools for creating phosphorus efficient crop varieties

This paper provides a brief assessment of the genetic variation in root properties (root morphology, including root hairs), mycorrhizal symbiosis, uptake kinetics parameters and root-induced changes (pH, organic acids and acid phosphatase) in the rhizosphere of various crop species and their genotypes and then briefly discusses the opportunities and challenges of using such knowledge for enhancing P efficiency of future crop genotypes by genetic means. Wide genotypic variation and heritability of root morphology, root hair length and density and thereby P acquisition provide opportunities for selection and breeding for root characteristics for increasing P acquisition. The progress is challenged by the concerns of high carbon cost of larger root systems and by the lack of cost effective methods to determine root length of a large number of genotypes under field conditions. The carbon cost of root hairs is low. Furthermore, low cost methods now exist to compare root hair formation of field grown genotypes. The development and application of sophisticated methods has advanced our knowledge on the role of mycorrhizal symbiosis in P acquisition and also on the molecular basis of fungi and plant interactions. However, extensive studies to explore genotypic variation in mycorrhizal responsiveness are rare, which makes it difficult to assess, how mycorrhizal symbiosis can be manipulated through breeding efforts. The promising variation found in P uptake kinetics parameters of crop genotypes in few studies indicates that more genotypes may be screened by relatively simple nutrient solution culture techniques. The genetic manipulation of the overall differences in cation-anion uptake, which is the main cause of rhizosphere pH change, may be difficult. For manipulation of rhizosphere pH, agronomic measures such as applications of ammonium or nitrate fertilisers may be more useful than breeding approaches. Also it seems difficult to assess what kind of genetic analysis should be performed to support the breeding efforts. Phosphorus mobilisation effect of pH depends on soil P compounds, therefore will differ with soil type. Both the enhanced release of organic acids and higher acid phosphatase activity in the rhizosphere may be useful for increasing P acquisition from inorganic and organic P pools, respectively. Modification of these traits by genetic means should be considered. For successful breeding programmes, the role of various root traits needs to be targeted in an integrated manner and then methods need to be developed for studying their importance under natural soil conditions, so that the genotypic variation can be explored and their ecological significance in P acquisition can be established.     

Clinical pharmacology of the new COMT inhibitor CGP 28 014

CGP 28 014 is a specific inhibitor of catechol-O-methyltransferase (COMT) in vivo. In humans, the inhibition was assessed by measuring urinary excretion of isoquinolines and with the levodopa test. Following administration of CGP 28 014, urinary excretion of isoquinolines was significantly increased. In rats, CGP 28 014 reduced plasma and striatal concentrations of 3-O-methyldopa (30MD) in a dose-dependent manner. Acute and subchronic administration of CGP 28 014 alone or in combination with the peripherally acting decarboxylase inhibitor benserazide decreased plasma 30MD as an index of COMT inhibition by about 50%. There seems to be a close relationship between the time-course of plasma concentrations of CGP 28 014 and the extent of COMT inhibition assessed by the 30MD/DOPA ratio in plasma.