Seed-bank convergence under different tree species during forest development

Seed banks are of vital importance for local plant persistence and recruitment, for maintaining both plant and genetic diversity and for habitat restoration. Yet, seed-bank dynamics, particularly on the long term and in deciduous forests, remain poorly understood. Additionally, information on compositional seed-bank differences under contrasting tree canopies remains scarce.This study aims at quantifying long-term seed-bank dynamics by sampling vegetation and seed banks along a four-stage successional chronosequence (40, 80, 120 and 250 years) using 12 10. m×10. m plots per forest stand age-class under fully developed oak-hornbeam and beech canopies.Seed banks were remarkably abundant and diverse. Species richness and seed density declined steeply with forest stand age, regardless of canopy species. Seed-bank composition differed significantly with stand age, yet also with tree species. Most likely, tree species-dependent ecosystem engineer effects on light availability and possibly also litter quality affect the seed bank through the vegetation. Compositional differences between seed banks from stands with a different canopy diminished with increasing stand age, possibly due to a gradual loss of species with a less persistent seed bank.Long-term seed-bank dynamics in deciduous forests seem to consist predominantly of a unidirectional and predictable depletion of the seed bank as long as large disturbances, which would allow seed-bank replenishment of early-successional species, are lacking. Furthermore, forest seed-banks appear to converge upon a characteristic seed bank in the later stages of forest development, irrespective of canopy composition, driven by seed-bank depletion and limited input from the herb layer. © 2010 Rübel Foundation, ETH Zürich.status: publishe

Verdienmodellen voor extensieve landbouwbedrijven: pijlers, principes en perspectieven

Extensive dairy and arable farms need business models to be able to make a sustainable contribution to policy goals regarding biodiversity and water quality. This report presents and analysis calculated exemplars of business models based on (combinations of) reduced costs, enhanced revenues and development opportunities for the farm. Based on that, opportunities for action by the government are identified to enable business models for extensive farms

A nitrilase-mediated entry to 4-carboxymethyl-β-lactams from chemically prepared 4-(cyanomethyl)azetidin-2-ones

(3R, 4S)-3-Alkoxy/aryloxy-4-(cyanomethyl) azetidin-2-ones were efficiently prepared from readily available 1,2: 5,6-di-D-isopropylidene-D-mannitol by means of a classical organic synthesis approach via 4-hydroxymethyl-beta-lactams as key intermediates. The corresponding 4-carboxymethyl-beta-lactams were subsequently obtained after selective hydrolysis of the nitrile functionality by means of a nitrilase enzyme without affecting the sensitive four-membered ring system, hence overcoming the difficulties associated with the chemical hydrolysis approach. Thus, the implementation of a biocatalytic step allows a convenient synthetic route to new 4-carboxymethyl-beta-lactams as versatile building blocks for further elaboration

P-removal for restoration of Nardus grasslands on former agricultural land : cutting traditions

Past intensive land use complicates the successful restoration of oligotrophic species-rich grassland types. One of the major bottlenecks are the elevated nutrient levels due to fertilization, especially residual phosphorus (P). Aiming to deplete nutrients, managers often reintroduce traditional haymaking management, sometimes combined with grazing. Here, we evaluate whether this technique restores the abiotic and biotic boundary conditions for restoration of Nardus grassland. Seven grasslands were selected in Flanders, Belgium, which had elevated nutrient levels after the cessation of intensive agriculture 16 to 24 years ago, and which have been mown and grazed since. We compared soil and vegetation data of these post-fertilization grasslands with 34 well-developed oligotrophic Nardus grasslands. Mowing and grazing did not cause community composition to resemble that of Nardus grassland. Furthermore, bioavailable P-concentrations were significantly higher in the post-fertilization grasslands and P-limitation was not obtained. Restoring P-poor soil conditions through continued mowing and grazing management would take at least decades. Phosphorus-mining can shorten the restoration time by increased P-removal. Given our results, we propose a decision framework to aid planners and managers in their choice of interventions. Cost-effective efforts for restoration should be well-prepared including measurements of important initial soil characteristics. This allows for an evaluation of “distance to target” and the selection of an effective restoration technique. These techniques may involve cutting with mowing tradition and utilizing P-mining or topsoil removal

Homozygosity for a FBN1 missense mutations: clinical and molecular evidence for recessive Marfan syndrome.

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Phagocytes Containing a Disease-Promoting Toll-Like Receptor/Nod Ligand Are Present in the Brain during Demyelinating Disease in Primates

Recent studies claim a central role for Toll-like receptor (TLR) ligands in stimulating autoimmune disease by activation of antigen-presenting cells in the target organ, but it is unclear if and how TLR ligands reach target organs. Most evidence comes from rodent models, and it is uncertain whether this principle holds in primates. Here we identify which cells contain peptidoglycan (PGN) in multiple sclerosis brain and in two nonhuman primate experimental autoimmune encephalomyelitis (EAE) models with different disease courses: acute (rhesus monkey) versus chronic disease (marmoset). Because persistence of TLR ligands in the central nervous system might be consequential for disease progression, we also determined the expression of two major PGN-degrading enzymes, ie, lysozyme and N-acetylmuramyl-l-alanine amidase. Distinct phagocyte subsets, including granulocytes, macrophages, and dendritic cells, contained PGN in the brain and coexpressed the inflammatory cytokine interleukin-12. The number of phagocytes carrying PGN increased in acute and chronic EAE compared with control animals, with the highest number of PGN-containing cells in acute EAE brain. Lytic enzymes were scarcely expressed in monkey and multiple sclerosis brain, favoring PGN persistence. PGN stimulated interleukin-12p70 release by leukocytes from all three primate species. The presence of PGN in the inflamed brain may have major implications because TLR2/Nod ligation potentially promotes inflammation and disease progression

A conservative and minimally invasive approach to necrotizing pancreatitis improves outcome

Item does not contain fulltextBACKGROUND & AIMS: Treatment of patients with necrotizing pancreatitis has become more conservative and less invasive, but there are few data from prospective studies to support the efficacy of this change. We performed a prospective multicenter study of treatment outcomes among patients with necrotizing pancreatitis. METHODS: We collected data from 639 consecutive patients with necrotizing pancreatitis, from 2004 to 2008, treated at 21 Dutch hospitals. Data were analyzed for disease severity, interventions (radiologic, endoscopic, surgical), and outcome. RESULTS: Overall mortality was 15% (n=93). Organ failure occurred in 240 patients (38%), with 35% mortality. Treatment was conservative in 397 patients (62%), with 7% mortality. An intervention was performed in 242 patients (38%), with 27% mortality; this included early emergency laparotomy in 32 patients (5%), with 78% mortality. Patients with longer times between admission and intervention had lower mortality: 0 to 14 days, 56%; 14 to 29 days, 26%; and >29 days, 15% (P<.001). A total of 208 patients (33%) received interventions for infected necrosis, with 19% mortality. Catheter drainage was most often performed as the first intervention (63% of cases), without additional necrosectomy in 35% of patients. Primary catheter drainage had fewer complications than primary necrosectomy (42% vs 64%, P=.003). Patients with pancreatic parenchymal necrosis (n=324), compared with patients with only peripancreatic necrosis (n=315), had a higher risk of organ failure (50% vs 24%, P<.001) and mortality (20% vs 9%, P<.001). CONCLUSIONS: Approximately 62% of patients with necrotizing pancreatitis can be treated without an intervention and with low mortality. In patients with infected necrosis, delayed intervention and catheter drainage as first treatment improves outcome