Effect of the US3 protein of bovine herpesvirus 5 on the actin cytoskeleton and apoptosis

The US3 protein is a unique protein kinase only present in the Alphaherpesvirinae subfamily of the herpesviruses. Studies performed with several alphaherpesviruses demonstrated that the US3 protein is involved in cytoskeleton modifications during viral infection and displays anti-apoptotic activity. However, the US3 protein of BoHV-5 has not been studied up to now. As reported for other alphaherpesviruses, our results showed that BoHV-5 US3 confers resistance against apoptosis and induces cytoskeletal reorganization leading to cell rounding, actin stress fiber breakdown and cell projections that interconnect cells. The expression of a kinase-dead version of BoHV-5 US3 showed that the anti-apoptotic activity and the induction of cell projections are kinase-dependent whereas kinase activity is not absolutely required for actin stress fiber breakdown. Besides, the kinase-dead version of US3, but not the wild type protein, was found excluded from the nucleus. These results constitute the first report on the BoHV-5 US3 functions, and highlight that there are functional differences and similarities among US3 proteins of different alphaherpesviruses.     

Angiotensin I-converting enzyme inhibitory activity of gelatin hydrolysates and identification of bioactive peptides

In this project we report on the angiotensin I-converting enzyme (ACE)-inhibitory activity of a bovine gelatin hydrolysate (Bh2) that was submitted to further hydrolysis by different enzymes. The thermolysin hydrolysate (Bh2t) showed the highest in vitro ACE inhibitory activity, and interestingly a marked in vivo blood pressure-lowering effect was demonstrated in spontaneously hypertensive rats (SHR). In contrast, Bh2 showed no effect in SHR, confirming the need for the extra thermolysin hydrolysis. Hence, an angiotensin I-evoked contractile response in isolated rat aortic rings was inhibited by Bh2t, but not by Bh2, suggesting ACE inhibition as the underlying antihypertensive mechanism for Bh2t. Using mass spectrometry, seven small peptides, AG, AGP, VGP, PY, QY, DY and IY or LY or HO-PY were identified in Bh2t. As these peptides showed ACE inhibitory activity and were more prominent in Bh2t than in Bh2, the current data provide evidence that these contribute to the antihypertensive effect of Bh2t.     

Effects of pulsation rate and viscosity on pulsation-induced taste enhancement: new insights into texture-taste interactions

Oral stimulation with high-tastant concentrations that are alternared with low-tastant concentrations or water rinses (pulsatile stimulation) results in taste intensity ratings that are higher than continuous stimulation with the same average tastant concentration. This study tested the combined effects of taste pulsation rate and viscosity on pulsation-induced taste enhancement in apple juice. According to a tastant-kinetics hypothesis, less pulsation-induced taste enhancement is expected at enhanced pulsation rates in the high-viscous proximal stimulus compared to lower viscous stimuli. High-concentration sucrose apple juice pulses and low-concentration sucrose apple juice intervals were alternated at different pulsation periods (pulse + interval in seconds) every 2.5 s (period length = 5 s) or every 1.25 s (period length = 2.5 s). Pulsed stimuli were presented at two viscosity levels by the addition of pectin (0 and 10 g/L). Sweetness intensities of pulsed stimuli were compared to a continuous reference of the same net but nonalternating sucrose concentration. Sweetness ratings were higher for pulsatile stimuli than for continuous stimuli. In low-viscous stimuli, enhancement depended on the pulsation period and peaked at 5 s periods. In high-viscous stimuli, the same enhancement was observed for both pulsation periods. These results contradict a tastant-kinetics hypothesis of viscosity-induced taste suppression because impaired tastant kinetics by viscosity would predict the opposite: lower pulsation-induced taste enhancement for viscous stimuli, especially at higher pulsation rates. Instead, these observations favor an explanation based on perceptual texture-taste interactions, which predict the observed independence between viscosity and pulsation rate.     

Soil organic C variability and microbial functions in a Mediterranean agro-forest ecosystem

Five soils characterised by different agro-forest managements, typical of Mediterranean environment and with increasing human impact were chosen in Sardinia (Italy): two vineyards with different management systems, a rotation hay crop-pasture and a forest (Quercus suber L.). The study aimed to investigate the relationships between C storage and microbial functionality in soil under different managements. Pools of total organic C and microbial biomass C were determined, as well as the loss of organic C due to microbial respiration (basal and cumulative) and several microbial indices (metabolic, mineralization, and microbial quotient) as indicators of the microbial efficiency in the use of energy and the degree of substrate limitation for soil microbes. Enzymes were chosen on their relevance in the C (β-cellobiohydrolase, N-acetyl-β-glucosaminidase, β-glucosidase, α-glucosidase), N (leucine aminopeptidase), S (arylsulphatase) and P (acid phosphatase) cycling and were used as indicators of functional diversity in soil. Organic C pools and enzyme activities on average increased noticeably in soils with a lower human impact showing the highest values in forest and the lowest in the vineyards, following the trend of organic matter availability. The trend in functional diversity reflected the increase of microbial pool and organic C availability: the vineyards showed a lower Shannon’s diversity index, whilst pasture and forest sites reached the maximum levels of functional diversity. These soils showed an increase of microbial efficiency in the use of available resources and the decrease of substrate limitation for soil microbes.     

Speciation of heavy metals in garden soils: evidences from selective and sequential chemical leaching

Purpose  

Gardening (especially food growing) in urban areas is becoming popular, but urban soils are often very contaminated for historical reasons. There is lack of sufficient information as to the bioavailability of soil heavy metals to plants and human in urban environments. This study examines the relative leachability of Cr, Ni, As, Cd, Zn, and Pb for soils with varying characteristics. The speciation and mobility of these metals can be qualitatively inferred from the leaching experiments. The goal is to use the data to shed some light on their bioavailability to plant and human, as well as the basis for soil remediation.     

Interlaboratory evaluation of a real-time multiplex polymerase chain reaction method for identification of salmon and trout species in commercial products

This interlaboratory study evaluated a real-time multiplex polymerase chain reaction (PCR) method for identification of salmon and trout species in a range of commercial products in North America. Eighty salmon and trout products were tested with this method by three independent laboratories. Samples were collected in the United States and Canada, and only the collecting institution was aware of the species declaration. Following analysis with real-time PCR, all three laboratories were able to identify species in 79 of the 80 products, with 100% agreement on species assignment. A low level of fraud was detected, with only four products (5%) found to be substituted or mixtures of two species. The results for two of the fraudulent products were confirmed with alternate methods, but the other two products were heavily processed and could not be verified with methods other than real-time PCR. Overall, the results of this study show the usefulness and versatility of this real-time PCR method for the identification of commercial salmon and trout species.     

Sedimentary and diagenetic features in saline lake deposits of the Monegros region, northern Spain

The Monegros region in northern Spain is marked by the occurrence of a large number of ephemeral to dry lake basins, occupying small karstic depressions. The lacustrine sediment fill of these basins contain various carbonate and silicate minerals whose origin and palaeoenvironmental significance is poorly understood. For the present study, 14 lake basins were sampled in order to establish vertical, lateral and regional variations in mineralogical and textural characteristics, aimed at determining the mode of formation of the various mineral phases present. In nearly all basins, the same sequence of three lithological units is recognized, including a basal clayey unit, a middle magnesite-bearing and gypsum-rich unit, and a calcite- and dolomite-dominated surface unit. Distribution patterns of carbonate minerals indicate that magnesite is a synsedimentary precipitate, dolomite formed as a diagenetic authigenic phase, and calcite is partly authigenic and partly allogenic. All clay minerals, including sepiolite and smectite, appear to be allogenic. Regional variations are marked by similarities between groups of neighbouring basins, but no overall trend related to regional drainage patterns is recognized. The middle lithological unit records a lake stage with predominantly chemical sedimentation (Unit II), overlying a less well documented interval corresponding to a perennial lake stage with lower salinity (Unit III), whereas the surface unit formed during a period with predominantly clastic sedimentation. Based on a comparison with other regional records, the middle unit is attributed to an Early Holocene humid stage, separated from the overlying Late Holocene deposits by a hiatus that corresponds to a Mid Holocene arid stage.     

Oxygen exchange with water alters the oxygen isotopic signature of nitrate in soil ecosystems

Combined oxygen (O) and nitrogen (N) stable isotope analyses are commonly used in the source determination of nitrate . The source and fate of are studied based on distinct O and N isotopic signatures (δ¹⁸O and δ¹⁵N) of various sources and isotopic effects during transformation processes, which differ between sources like fertilizer, atmospheric deposition, and microbial production (nitrification). Isotopic fractionation during production and consumption of further affects the δ¹⁸O and δ¹⁵N signal. Regarding the δ¹⁸O in particular, biochemical O exchange between O from and H₂O is implicitly assumed not to affect the δ¹⁸O signature of . This study aimed to test this assumption in soil-based systems. In a short (24 h) incubation experiment, soils were treated with artificially ¹⁸O and ¹⁵N enriched . Production of from nitrification during the incubation would affect both the ¹⁸O and the ¹⁵N enrichment. Oxygen exchange could therefore be studied by examining the change in ¹⁸O relative to the ¹⁵N. In two out of the three soils, we found that the imposed ¹⁸O enrichment of the declined relatively more than the imposed enrichment. This implies that O exchange indeed affected the O isotopic signature of , which has important implications for source determination studies. We suggest that O exchange between and H₂O should be taken into consideration when interpreting the O isotopic signature to study the origin and fate of in ecosystems.     

Foliar Nitrogen Uptake from Wet Deposition and the Relation with Leaf Wettability and Water Storage Capacity

This study assessed the foliar uptake of ¹⁵N-labelled nitrogen (N) originating from wet deposition along with leaf surface conditions, measured by wettability and water storage capacity. Foliar ¹⁵N uptake was measured on saplings of silver birch, European beech, pedunculate oak and Scots pine and the effect of nitrogen form (NH ₄ ⁺ or NO ₃ ^? ), NH ₄ ⁺ to NO ₃ ^? ratio and leaf phenology on this N uptake was assessed. Next to this, leaf wettability and water storage capacity were determined for each tree species and phenological stage, and the relationship with ¹⁵NH ₄ ⁺ and ¹⁵NO ₃ ^? uptake was examined. Uptake rates were on average five times higher (p?<?0.05) for NH ₄ ⁺ than for NO ₃ ^? and four times higher for deciduous species than for Scots pine. Developing leaves showed lower uptake than fully developed and senescent leaves, but this effect was tree species dependent. The applied NH ₄ ⁺ to NO ₃ ^? ratio did only affect the amount of N uptake by senescent leaves. The negative correlation between measured leaf contact angles and foliar N uptake demonstrates that the observed effects of tree species and phenological stage are related to differences in leaf wettability and not to water storage capacity.