Faster fermentation of cooked carrot cell clusters compared to cell wall fragments in vitro by porcine feces

Plant cell walls are the major structural component of fruits and vegetables, which break down to cell wall particles during ingestion (oral mastication) or food processing. The major health-promoting effect of cell walls occurs when they reach the colon and are fermented by the gut microbiota. In this study, the fermentation kinetics of carrot cell wall particle dispersions with different particle size and microstructure were investigated in vitro using porcine feces. The cumulative gas production and short-chain fatty acids (SCFAs) produced were measured at time intervals up to 48 h. The results show that larger cell clusters with an average particle size (d(0.5)) of 298 and 137 μm were more rapidly fermented and produced more SCFAs and gas than smaller single cells (75 μm) or cell fragments (50 μm), particularly between 8 and 20 h. Confocal microscopy suggests that the junctions between cells provides an environment that promotes bacterial growth, outweighing the greater specific surface area of smaller particles as a driver for more rapid fermentation. The study demonstrates that it may be possible, by controlling the size of cell wall particles, to design plant-based foods for fiber delivery and promotion of colon fermentation to maximize the potential for human health.     

Forest fuel management as a conservation tool for early successional species under agricultural abandonment: The case of Mediterranean butterflies

In cultural landscapes there are often negative biodiversity consequences of agricultural abandonment and subsequent scrub and forest encroachment, due to homogenization and the loss of early-successional habitats. The common forestry practice of removing understory vegetation to prevent fire hazard (fuel management) probably has the side-effect of ameliorating these consequences, but it is uncertain whether it effectively restores habitats for early-successional species. Here we examine the influence of time since fuel management and management frequency on butterfly assemblages, using a chronosequence of cork oak (Quercus suber) stands spanning about 70 years. Overall species richness increased immediately after management and abundances peaked about 2–3 years later, while both declined thereafter for about 10–20 years to pre-disturbance levels. Richness and abundances were also much higher in recurrently managed stands. Most life history groups showed successional trends similar to the overall species richness and abundances, though consistent positive effects of fuel management were only observed for species with univoltine life cycle, herbaceous layer feeding, larval overwintering, and intermediate body size. Individual species were largely associated with recent and recurrent management, though a few specialists occurred most often in undisturbed stands. These findings suggest that fuel management at <10 years intervals is strongly positive for butterfly assemblages in landscapes under land abandonment. However, to maintain the overall forest biodiversity it is critical that patches of undisturbed habitat are also retained at the landscape scale.     

In vitro fermentation of alternansucrase raffinose-derived oligosaccharides by human gut bacteria

In this work, in vitro fermentation of alternansucrase raffinose-derived oligosaccharides, previously fractionated according to their degree of polymerization (DP; from DP4 to DP10), was carried out using small-scale pH-controlled batch cultures at 37 °C under anaerobic conditions with human feces. Bifidogenic activity of oligosaccharides with DP4-6 similar to that of lactulose was observed; however, in general, a significant growth of lactic acid bacteria Bacteroides , Atopobium cluster, and Clostridium histolyticum group was not shown during incubation. Acetic acid was the main short chain fatty acid (SCFA) produced during the fermentation process; the highest levels of this acid were shown by alternansucrase raffinose acceptor pentasaccharides at 10 h (63.11 mM) and heptasaccharides at 24 h (54.71 mM). No significant differences between the gas volume produced by the mixture of raffinose-based oligosaccharides (DP5-DP10) and inulin after 24 h of incubation were detected, whereas lower gas volume was generated by DP4 oligosaccharides. These findings indicate that novel raffinose-derived oligosaccharides (DP4-DP10) could be a new source of prebiotic carbohydrates.     

Nitrogen leaching from a forest soil exposed to fire retardant with and without fire: A laboratory study

The application of Long Term fire Retardants (LTRs) for forest fire prevention and/or suppression purposes can result in chemicals leaching, from soil to the drainage water, during the annual rain fall period. In leachates, large concentrations of nitrogen (N), one of the major components of LTRs, could affect the groundwater quality. N leaching due to the application of a nitrogen phosphate based LTR was studied in laboratory microcosms. The concentrations of nitrate (NO ₃ ^? -N) and ammonium nitrogen (NH ₄ ⁺ -N) were measured in the resulting leachates from pots with forest soil and pine seedlings (Pinus halepensis) alone and in combination with fire. Up to 30% of the total N in the retardant was lost to leaching, primarily as NO ₃ ^? -N. The vegetation seems to decrease to some extent the N leaching. The N leaching from treated pots with a burnt tree is lower compared with that from treated pots with a living tree, due to the partial N volatilization during the fire. Although this is a laboratory study, these results may be considered as rough indications of LTR environmental implications, due to the leaching of a significant part of the retardant’s N into groundwater.     

Alkaloids from Sarcomelicope megistophylla

Two new alkaloids were isolated from the bark of Sarcomelicope megistophylla. Cyclomegistine B (1), a new quinolone alkaloid, that possesses a rare cyclobuta[b]quinoline ring system and sarcomejine B (2) which is a quinolone alkaloid with an unusual side chain. The structure of both compounds was elucidated on the basis of MS data and extensive NMR studies.     

Circumferential variation of heartwood and stem quality in maritime pine stems

Maritime pine (Pinus pinaster Ait.) is an important timber and pulpwood species covering about 4 million ha in Portugal, Spain and France. This work studied the cross-sectional distribution of heartwood and sapwood along the stem using 3D modelling on 20 trees. The target was to assess the potential of this species for the industrial production of heartwood sawn products. The maritime pine stems were characterized by wide sapwood of 10 cm, in average, and the presence of heartwood at all height levels with constant diameter up to 35 % tree height, decreasing afterwards. In the radial section, the heartwood follows a circumferential-like shape which changes along the stem. Pith eccentricity index values were low and homogeneous regarding to stem and higher for heartwood. Heartwood cross-sectional shape was constant up to 45 % of total height of the tree and more elongated upwards. The constant heartwood diameter, low taper and pith eccentricity index, and an approximate circular shape up to 10 m height indicated these species’ potential to produce solid wood products made out of heartwood.     

Rearing temperature affects Senegalese sole (Solea senegalensis) larvae protein metabolic capacity

The present work examined the short- and long-term effects of three rearing temperatures on protein metabolism and growth trajectories of Senegalese sole larvae using ¹⁴C-labelled Artemia protein as feed. A first feeding trial was performed on larvae reared at 15, 18 and 21 °C (at 26, 17 and 14 days post-hatching (dph), respectively) and a second trial conducted on post-larvae after transfer to the same rearing temperature (~20 °C) (49, 35 and 27 dph, in larvae initially reared at 15, 18 and 21 °C, respectively). Temperature greatly influenced larvae relative growth rate (RGR) and survival, since growth at 15 °C was severely depressed. Protein digestibility and retention was highest at 18 °C during the first trial (85.35 ± 1.16 and 86.34 ± 2.33 %, respectively). However, during the second trial, post-larvae from 15 °C had the highest feed intake and protein digestibility (3.58 ± 1.54 and 75.50 ± 1.35 %, respectively), although retention was similar between treatments. Furthermore, after transfer to 20 °C larvae from 15 °C experienced compensatory growth, which was observed until 121 dph, and confirmed by RGR values, which were significantly higher at 15 ºC than at 21 ºC or 18 ºC. Results from the present study show that Solea senegalensis larval development, survival and protein digestion and retention are highly affected by thermal history.     

Passive and Active Sampling of Benzene in Different Urban Environments in Gothenburg, Sweden

Urban benzene concentration and personal exposure to benzene were measured within different urban environments in Gothenburg, Sweden. Three intensive monitoring campaigns were carried out in May 2000, February 2001 and May 2001. Three different environments were selected; two central built-up areas with different traffic densities (high and low) and one large urban park. The methods used included passive and active sampling. Passive sampling was used to retrieve spatial variability in urban benzene concentrations, while active sampling aimed to give data on personal exposure levels within the designated areas. The passive sampling showed large spatial and temporal variations in urban benzene concentrations. The benzene concentrations, ranging from 1.0 to 3.1 μg m^?3, were typically two to four times higher within the high-traffic built-up area compared to the adjacent urban park. This was mainly due to the proximity to motorised traffic. A comparison between personal exposure and active stationary measurements showed that the personal exposure levels were roughly 1.5 times higher in the heavy traffic area and 1.3 times higher in the light traffic area than the fixed benzene concentrations. The personal exposure levels in the park were equal to the active stationary benzene concentration. Given the large spatial heterogeneity within urban areas, the placement of single street level point measurements becomes crucial. Care must be taken to ensure that the measurements are actually representative when using these measurements to estimate urban concentrations and exposure levels.     

Effects of ketamine constant rate infusions on cardiac biomarkers and cardiac function in dogs

Objective

To evaluate the effects of ketamine continuous rate infusions (CRI) at two dose rates on cardiovascular function and serum creatine kinase MB isoenzyme (CK-MB) and troponin I in healthy conscious dogs.