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Safety assessment of the substance, montmorillonite clay modified with hexadecyltrimethylammonium bromide, for use in food contact materials
No full textThe EFSA Panelon Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of montmorillonite clay modified with hexadecyltrimethylammonium bromide (HDTA) when used as an additive at up to |||| in polylactic acid (PLA) bottles intended for contact with water for long-term storage at ambient temperature or below. The modified clay, which 90% w/w of the particles have a dimension of 33.1m or less and the average size is 9m, has a layered structure with layers of a thickness below 100nm. When incorporated in PLA, nanosized layers can be dispersed in the matrix, but are not expected to migrate. Thermal degradation is not expected at the maximum manufacturing temperature. No loss of integrity of the PLA surface due to interaction with bottled water was observed. The overall migration was very low. No migration of HDTA was detected at the limit of detection |||||. Migration of aluminium was below or at the limit of detection |||||, which would conservatively correspond to approximately ||||. Comparative analysis of bottled water with and without the modified clay did not reveal additional peaks corresponding to impurities identified in the modifier and/or in the modified clay. Moreover, |||||, and the modifier HDTA have been evaluated and authorised. Therefore, the CEP Panelconcluded that the substance montmorillonite clay modified with HDTA bromide is not of safety concern for the consumer if the substance is used as an additive at up to |||| in PLA plastic bottles and other containers intended for long-term storage of water at ambient temperature or below, as requested by the applicant
Low effective population sizes in Amblyomma variegatum, the tropical bont tick
No full textEffective population sizes have rarely been estimated in ticks despite the importance of this parameter for evaluating the evolutionary and adaptive potential of tick populations. The present study was aimed at evaluating the effective population sizes of Amblyomma variegatum, the tropical bont tick, in three villages in Burkina Faso. For this purpose, microsatellites markers were developed. Eight out of 19 assessed markers provided good amplification results with 4 to 24 alleles recorded per marker on 216 genotyped ticks. The within-samples polymorphism was congruent with Hardy-Weinberg expectations at four markers while sex linkage and/or null alleles were observed at the others. As sampling involved two tick generations, effective population sizes were independently estimated by two methods insensitive to heterozygosity: the first one is based on linkage disequilibrium analysis within a single cohort while the second uses the changes in allele frequencies across generations. Both methods estimated the number of reproducing ticks ranging from two to a few tens reproductive adults per village and cohort. Such small estimates are congruent with the rarity of records of acaricide resistance in A. variegatum
Profound Changes in Net Energy and Nitrogen Metabolites Fluxes within the Splanchnic Area during Overfeeding of Yucatan Mini Pigs That Remain Euglycemic
No full textA dysregulation of nutrient exchange between tissues (gut, liver, muscles, adipose) occurs during overnutrition and could induce obesity and metabolic diseases. We aimed to evaluate how, in overfed mini pigs, nutrients use and partition were regulated in the gut and liver. Net nutrients fluxes were assessed in the fed (PP) and post absorptive (PA) states at 1, 14 and 60 days of adaptation to overfeeding in five adult Yucatan female multicatheterized minipigs. Pigs PA glycaemia and PP-induced hyperglycemia remained unchanged over the experimental period, suggesting that the management of the excess of energy intake allowed the maintenance of glucose levels. This was associated with (1) an increased PA plasma insulin, (2) an increased gut lactate production (increased lactate net release +89%, 1 h PP, D1 vs. D60) probably from an increased glucose oxidation, (3) a shift in utilization of gluconeogenic precursor (lactate, propionate) in the liver, and (4) a reduced gut utilization of nitrogen moieties for energy purposes (glutamine), a nitrogen sparing effect at the whole body level (decreased plasma urea in PA (-24% D1 vs. D60) and PP states) and a specific increased level of AA involved in lipids handling and bile recycling in the gut lumen (taurine and glycine)
Termination of pupal diapause in the pine processionary moth Thaumetopoea pityocampa
No full textDiapause development is a complex process involving several eco-physiological phases. Understanding these phases, especially diapause termination, is vital for interpreting the life history of many insect species and for developing suitable predictive models of population dynamics. The pine processionary moth is a major defoliator of pine and a vertebrate health hazard in the Mediterranean region. This species can display either univoltine or semivoltine development, with a pupal diapause extending from a few months to several years, respectively. Although the ecological and applied importance of diapause is acknowledged, its physiological regulation in either case remains obscure. In the present study, we characterize pre-termination, termination and post-termination phases of pupae developing as univoltine or remaining in prolonged diapause. Changes in metabolic activity are monitored continuously using thermocouples, comprising a novel method based on direct calorimetry, and periodically by use of O-2 respirometry. The two methods clearly detect diapause termination in both types of pupae before any visible morphological or behavioural changes can be observed. Univoltine individuals are characterized by an increase in metabolic activity from pre-termination through to termination and post-termination, ultimately resulting in emergence. Remarkably, a synchronous termination is observed in individuals that enter prolonged diapause instead of emerging; however, in these pupae, the increased metabolic activity is only transient. The present study represents a starting point toward understanding the eco-physiology of diapause development processes in the pupae of the pine processionary moth
Reduced Skeletal Muscle Protein Turnover and Thyroid Hormone Metabolism in Adaptive Thermogenesis That Facilitates Body Fat Recovery During Weight Regain
No full textWill climate change affect sugar beet crop emergence of the 21st century? Insight from a simulation study
No full textClimate change will result in increased mean temperature, precipitation variability and altered frequency of extreme temperature events in many regions of the globe, including Europe. While many studies focused on evaluating the impacts of climate change on crop yields, there is less detailed information about the potential effect of climate change on crop establishment, although it is a crucial stage of the annual crop cycles. This prevents stakeholders from mobilizing adaptation strategies which may be helpful to attenuate climate change effects. Rather small adjustments (e.g. changes in varieties, sowing date and density, tillage or tactical pest management) in contrast to more systemic changes (e.g. changes in crop sequences; moving from dryland to irrigated systems or from spring to autumn sowings) may ensure successful crop establishment. Exploration of adaptation strategies to climate change using process-based models allows crop-level evaluation and adaptations of existing cropping systems. Here we used a model-based framework, to evaluate changes in germination and emergence as well as bolting rates of sugar beet crop related to climate change in Northern France. We used the most pessimistic IPCC scenario (RCP 8.5) to generate soil temperature and water content of the seedbed using the STICS crop model (Brisson et al., 2003). We used the data obtained to feed the SIMPLE crop emergence model (Dürr et al., 2001). A total of 810 sugar beet emergence simulations were performed for a period 2020-2100, taking into account five sowing dates (mid-February, 1st March, mid-March, 1st April and mid-April) and two First, our results provided information on the changes that will occur in future sowing conditions. The predicted cumulative rainfall for 30 days after sowing will be increasingly variable over time especially for the earlier sowings (Feb – March), with an increasing frequency of values lower than 20 mm and over 80 mm after 2050. The average maximum air temperature of the 30 days post-sowing will increase from 10°C to 12°C for the earliest sowing (mid-Feb.), with frequent values over 12°C after 2050. Second, despite the increased average temperatures, the simulated sowings indicate that the risk of reduced seed germination will remain high, with final germination rates lower than 50%, for the earlier sowing dates: 16 and 12 years out of 81 simulated for crop sown on the 15th February and 1st March, respectively. However, the use of primed seeds can alleviate this risk. The predicted bolting rates will remain very low, even for the earliest sowing dates. Overall, our results indicate that, in the future, sugar beet crop can still be sown earlier in spring than what occurs nowadays but the risk of establishment failure will remain quite high. These simulation results are useful to visualize the sowing conditions of the coming decades and pinpoint adaptive strategies for farmers or breeders. This analysis could not be possible without simulation models
Herbage intake and growth of rabbits under different pasture type, herbage allowance and quality conditions in organic production
No full textA lack of knowledge about rabbit herbage intake during grazing limits the development of organic rabbit production. This study describes rabbit herbage intake under a wide range of grazing conditions and characterises the factors that decrease rabbit herbage intake and daily weight gain. It was conducted with growing rabbits reared in moving cages with 0.4 m2 of grazing area per rabbit. Rabbits grazed on pastures dominated by legumes (LEG) or grass and forbs (GRF) and received 60 g/day per rabbit of a complete pelleted feed. Three trials were performed in winter, summer and spring. Mean herbage allowance was 27% higher in LEG (62.3 g dry matter (DM)/kg metabolic weight (MW), equal to kg0.75) than in GRF (49.2 g DM/kg MW). Herbage intake varied greatly (36.3±18.0 g DM/kg MW) among trials and was higher in LEG than in GRF (39.5v.34.1 g DM/kg MW). For both pasture types, herbage intake was logarithmically related to herbage allowance and plateaued around 75 g DM/kg MW. Crude protein and digestible energy (DE) intake differed by pasture type and season. Mean CP intake was 40% higher in LEG (15.0 g/kg MW) than in GRF (10.7 g/kg MW). In summer, mean DE intake was 27% higher in LEG than in GRF but no significant differences in DE intake were found between LEG and GRF in winter and spring. Maximum DE intake plateaued near 1000 kJ/kg MW. Daily weight gain was always higher for rabbits grazing LEG (mean=22.6 g) than GRF (mean=16.0 g). Weight gain was significantly related to CP intake, whereas DE intake had no significant effect. Meeting the objective of mean daily weight gain of 20 g requires herbage intake of 32 and 50 g DM/kg MW in LEG and GRF, respectively. Therefore, according to the herbage use efficiency observed in our experiments, herbage allowance must reach 42 and 78 g DM/kg MW in LEG and GRF, respectively. When herbage allowance is lower, rabbits cannot meet the CP intake (13 g/kg MW) required for this weight gain objective
Recombination and Large Structural Variations Shape Interspecific Edible Bananas Genomes
No full textAdmixture and polyploidization are major recognized eukaryotic genome evolutionary processes. Their impacts on genome dynamics vary among systems and are still partially deciphered. Many banana cultivars are triploid (sometimes diploid) interspecific hybrids between Musa acuminata (A genome) and M. balbisiana (B genome). They have no or very low fertility, are vegetatively propagated and have been classified as "AB," "AAB," or "ABB" based on morphological characters. We used NGS sequence data to characterize the A versus B chromosome composition of nine diploid and triploid interspecific cultivars, to compare the chromosome structures of A and B genomes and analyze A/B chromosome segregations in a polyploid context. We showed that interspecific recombination occurred frequently between A and B chromosomes. We identified two large structural variations between A and B genomes, a reciprocal translocation and an inversion that locally affected recombination and led to segregation distortion and aneuploidy in a triploid progeny. Interspecific recombination and large structural variations explained the mosaic genomes observed in edible bananas. The unprecedented resolution in deciphering their genome structure allowed us to start revisiting the origins of banana cultivars and provided new information to gain insight into the impact of interspecificity on genome evolution. It will also facilitate much more effective assessment of breeding strategies
