A viscoelastic deadly fluid in carnivorous pitcher plants

Background : The carnivorous plants of the genus Nepenthes, widely distributed in the Asian tropics, rely mostly on nutrients derived from arthropods trapped in their pitcher-shaped leaves and digested by their enzymatic fluid. The genus exhibits a great diversity of prey and pitcher forms and its mechanism of trapping has long intrigued scientists. The slippery inner surfaces of the pitchers, which can be waxy or highly wettable, have so far been considered as the key trapping devices. However, the occurrence of species lacking such epidermal specializations but still effective at trapping insects suggests the possible implication of other mechanisms. Methodology/Principal Findings : Using a combination of insect bioassays, high-speed video and rheological measurements, we show that the digestive fluid of Nepenthes rafflesiana is highly viscoelastic and that this physical property is crucial for the retention of insects in its traps. Trapping efficiency is shown to remain strong even when the fluid is highly diluted by water, as long as the elastic relaxation time of the fluid is higher than the typical time scale of insect movements. Conclusions/Significance : This finding challenges the common classification of Nepenthes pitchers as simple passive traps and is of great adaptive significance for these tropical plants, which are often submitted to high rainfalls and variations in fluid concentration. The viscoelastic trap constitutes a cryptic but potentially widespread adaptation of Nepenthes species and could be a homologous trait shared through common ancestry with the sundew (Drosera) flypaper plants. Such large production of a highly viscoelastic biopolymer fluid in permanent pools is nevertheless unique in the plant kingdom and suggests novel applications for pest control

Quantitative analysis of regional distribution of tau pathology with 11C-PBB3-PET in a clinical setting.

PURPOSE The recent developments of tau-positron emission tomography (tau-PET) enable in vivo assessment of neuropathological tau aggregates. Among the tau-specific tracers, the application of 11C-pyridinyl-butadienyl-benzothiazole 3 (11C-PBB3) in PET shows high sensitivity to Alzheimer disease (AD)-related tau deposition. The current study investigates the regional tau load in patients within the AD continuum, biomarker-negative individuals (BN) and patients with suspected non-AD pathophysiology (SNAP) using 11C-PBB3-PET. MATERIALS AND METHODS A total of 23 memory clinic outpatients with recent decline of episodic memory were examined using 11C-PBB3-PET. Pittsburg compound B (11C-PIB) PET was available for 17, 18F-flurodeoxyglucose (18F-FDG) PET for 16, and cerebrospinal fluid (CSF) protein levels for 11 patients. CSF biomarkers were considered abnormal based on Aβ42 ( 450 ng/L). The PET biomarkers were classified as positive or negative using statistical parametric mapping (SPM) analysis and visual assessment. Using the amyloid/tau/neurodegeneration (A/T/N) scheme, patients were grouped as within the AD continuum, SNAP, and BN based on amyloid and neurodegeneration status. The 11C-PBB3 load detected by PET was compared among the groups using both atlas-based and voxel-wise analyses. RESULTS Seven patients were identified as within the AD continuum, 10 SNAP and 6 BN. In voxel-wise analysis, significantly higher 11C-PBB3 binding was observed in the AD continuum group compared to the BN patients in the cingulate gyrus, tempo-parieto-occipital junction and frontal lobe. Compared to the SNAP group, patients within the AD continuum had a considerably increased 11C-PBB3 uptake in the posterior cingulate cortex. There was no significant difference between SNAP and BN groups. The atlas-based analysis supported the outcome of the voxel-wise quantification analysis. CONCLUSION Our results suggest that 11C-PBB3-PET can effectively analyze regional tau load and has the potential to differentiate patients in the AD continuum group from the BN and SNAP group

Temperature-Induced Increase in Methane Release from Peat Bogs: A Mesocosm Experiment

Peat bogs are primarily situated at mid to high latitudes and future climatic change projections indicate that these areas may become increasingly wetter and warmer. Methane emissions from peat bogs are reduced by symbiotic methane oxidizing bacteria (methanotrophs). Higher temperatures and increasing water levels will enhance methane production, but also methane oxidation. To unravel the temperature effect on methane and carbon cycling, a set of mesocosm experiments were executed, where intact peat cores containing actively growing Sphagnum were incubated at 5, 10, 15, 20, and 25°C. After two months of incubation, methane flux measurements indicated that, at increasing temperatures, methanotrophs are not able to fully compensate for the increasing methane production by methanogens. Net methane fluxes showed a strong temperature-dependence, with higher methane fluxes at higher temperatures. After removal of Sphagnum, methane fluxes were higher, increasing with increasing temperature. This indicates that the methanotrophs associated with Sphagnum plants play an important role in limiting the net methane flux from peat. Methanotrophs appear to consume almost all methane transported through diffusion between 5 and 15°C. Still, even though methane consumption increased with increasing temperature, the higher fluxes from the methane producing microbes could not be balanced by methanotrophic activity. The efficiency of the Sphagnum-methanotroph consortium as a filter for methane escape thus decreases with increasing temperature. Whereas 98% of the produced methane is retained at 5°C, this drops to approximately 50% at 25°C. This implies that warming at the mid to high latitudes may be enhanced through increased methane release from peat bogs

Safety of β-hydroxybutyrate salts as a novel food pursuant to Regulation (EU) 2015/2283

Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver an opinion on β-hydroxybutyrate (BHB) salts as a novel food (NF) pursuant to Regulation (EU) 2015/2283. The NF consists of sodium, magnesium and calcium BHB salts, and is proposed to be used by adults as a food ingredient in a number of food categories and as food supplement. The data provided by the applicant about the identity, the production process and the compositional data of the NF over the course of the risk assessment period were overall considered unsatisfactory. The Panel noted inconsistencies in the reporting of the test item used in the subchronic toxicity study and human studies provided by the applicant. Owing to these deficiencies, the Panel cannot establish a safe intake level of the NF. The Panel concludes that the safety of the NF has not been established

Safety of cellobiose as a novel food pursuant to regulation (EU) 2015/2283

[EN] Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver an opinion on cellobiose as a novel food (NF) pursuant to Regulation (EU) 2015/2283. The NF consists of two glucose monomers linked by a β-(1–4) glucosidic bond. The applicant intends to add the NF to a variety of foods, and to food supplements aimed at the general population 3 years and older. The information provided on the manufacturing process, composition and specifications of the NF is sufficient and does not raise safety concerns. The applicant provided a subchronic toxicological study which did not raise safety concerns. The applicant provided a human dose-escalation study from which the Panel concludes that the consumption of 20 g per day of cellobiose (equivalent to 290 mg/kg body weight (bw) per day in a 70-kg adult) does not raise concern regarding gastrointestinal tolerability. The maximum anticipated daily intake of cellobiose from the proposed uses is below 290 mg/kg bw per day in the target population. Considering the nature, source, compositional characterisation, and production process of the NF, as well as the toxicological data provided, the Panel considers that the NF does not raise safety concerns under the proposed conditions of useS

Safety of an aqueous ethanolic extract of Labisia pumila as a novel food pursuant to Regulation (EU) 2015/2283

[EN] Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver an opinion on aqueous extract of Labisia pumila as a novel food (NF) pursuant to Regulation (EU) 2015/2283. The NF is a standardised hydroalcoholic extract from a dried whole plant (including roots) of L. pumila, mixed with maltodextrin (as a drying aid), and proposed by the applicant to be used as a food supplement in amounts up to 750 mg/day. The target population is the general adult population, except pregnant and lactating women. The major constituents of this NF are carbohydrates (up to 85.5%), with a smaller amount of proteins (up to 6.5%), gallic acid (up to 3.7%) and fats (up to 1.6%). The Panel considers that taking into account the composition of the NF and the proposed conditions of use, consumption of the NF is not nutritionally disadvantageous. The provided genotoxicity studies do not raise concerns about the genotoxicity of the NF. Based on the available toxicological data, the Panel considers an intake of up to 5 mg/kg body weight per day as safe. For the target population, this level corresponds to 350 mg/day, which is lower than the use level proposed by the applicant. The Panel concludes that the NF is safe for the target population up to 350 mg/dayS

Safety of an aqueous ethanolic extract of Labisia pumila as a novel food pursuant to Regulation (EU) 2015/2283

Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver an opinion on aqueous extract of Labisia pumila as a novel food (NF) pursuant to Regulation (EU) 2015/2283. The NF is a standardised hydroalcoholic extract from a dried whole plant (including roots) of L. pumila, mixed with maltodextrin (as a drying aid), and proposed by the applicant to be used as a food supplement in amounts up to 750 mg/day. The target population is the general adult population, except pregnant and lactating women. The major constituents of this NF are carbohydrates (up to 85.5%), with a smaller amount of proteins (up to 6.5%), gallic acid (up to 3.7%) and fats (up to 1.6%). The Panel considers that taking into account the composition of the NF and the proposed conditions of use, consumption of the NF is not nutritionally disadvantageous. The provided genotoxicity studies do not raise concerns about the genotoxicity of the NF. Based on the available toxicological data, the Panel considers an intake of up to 5 mg/kg body weight per day as safe. For the target population, this level corresponds to 350 mg/day, which is lower than the use level proposed by the applicant. The Panel concludes that the NF is safe for the target population up to 350 mg/day

Safety of cellobiose as a novel food pursuant to regulation (EU) 2015/2283

Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver an opinion on cellobiose as a novel food (NF) pursuant to Regulation (EU) 2015/2283. The NF consists of two glucose monomers linked by a β-(1–4) glucosidic bond. The applicant intends to add the NF to a variety of foods, and to food supplements aimed at the general population 3 years and older. The information provided on the manufacturing process, composition and specifications of the NF is sufficient and does not raise safety concerns. The applicant provided a subchronic toxicological study which did not raise safety concerns. The applicant provided a human dose-escalation study from which the Panel concludes that the consumption of 20 g per day of cellobiose (equivalent to 290 mg/kg body weight (bw) per day in a 70-kg adult) does not raise concern regarding gastrointestinal tolerability. The maximum anticipated daily intake of cellobiose from the proposed uses is below 290 mg/kg bw per day in the target population. Considering the nature, source, compositional characterisation, and production process of the NF, as well as the toxicological data provided, the Panel considers that the NF does not raise safety concerns under the proposed conditions of use

Extension of use of nicotinamide riboside chloride as a novel food pursuant to Regulation (EU) 2015/2283

Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver an opinion on the safety of an extension of use of the novel food (NF) nicotinamide riboside chloride (NRC) pursuant to Regulation (EU) 2015/2283. The assessment addresses the use of NRC in ‘meal replacement products’ and ‘nutritional drink mixes’ at levels up to 300 mg/day for the general population, and in food for special medical purposes (FSMP) and total diet replacement for weight control (TDRWC) (as per Regulation (EU) No 609/2013) at levels up to 500 mg/day in adults. Benchmark dose modelling was carried out on data from the 90-day oral toxicity studies in rats relevant to the safety assessment. Considering the lack of tolerable upper intake level (UL) for nicotinamide in infants and the narrow margin of exposure between the estimated intake in infants and the lower confidence bound of the benchmark doses (BMDL05) estimated by the models, the Panel concludes that the safety of the NF has not been established for use in ‘meal replacement products’ and ‘nutritional drink mixes’ under the proposed conditions of use. For FSMP and TDRWC, the proposed maximum use level corresponds to an intake of 210 mg nicotinamide per day, which is below the current UL for nicotinamide of 900 mg/day for adults. The Panel considers that the NF is as safe as pure nicotinamide for use in FSMP and TDRWC. The Panel, however, notes experimental data which indicate several pathways by which intakes of nicotinamide (or its precursors), at levels that are substantially higher than the physiological requirement, might cause adverse effects. The Panel considers that further investigations are required and that a re-evaluation of the UL for nicotinamide may be warranted