Toxicity and tolerance of aluminium in vascular plants

Elevated levels of Al in soil solution may be toxic to plants. The activity of monomeric inorganic Al species is the best measure of the phytotoxic fraction. Decreasing soil pH increases soil solution Al exponentially as the pH falls below 4.5. In the presence of organic matter and organic acids the availability of A1 is reduced, due to complexation. The Al concentration is also dependent on dominant clay mineral and clay content. Symptoms of Al toxicity usually first appear in the roots becoming structurally and functionally damaged and inefficient in absorbing water and nutrients. This might be due to disturbance of mitosis and changed permeability of the root membranes. Aluminium also affects DNA replication, protein synthesis, and activity of some enzymes. Symptoms on shoots usually develop at a later stage of Al poisoning. There is an antagonism between the macronutrients P, Ca, Mg, and K on the one hand, and Al on the other. Aluminium may induce deficiency of mineral nutrients and high nutrient concentrations reduce al toxicity. There is considerable variation in Al tolerance between species and between varieties of the same species. Several mechanisms for Al tolerance are suggested. Tolerant plants may possess an active exclusion mechanism or may be able to inactivate Al within their tissues. pH increases induced by the plant in the rhizosphere, exudation of chelating agents, a low C.E.C. in the roots and an ability to withstand or compensate Al induced nutrient deficiency are other possible tolerance mechanisms.     

Effects of grinding and thermal treatments on hydrolysis susceptibility of pea proteins (Pisum sativum L.)

The effects of three particle sizes with two types of grindings and two thermal treatments on pea protein extraction (PE) and susceptibility to in vitro enzymatic hydrolysis (pepsin plus trypsin) were studied. Degrees of hydrolysis (DH) were calculated. Remaining peptides were detected by SDS-PAGE and identified by immunoblotting and MS/MS spectrometry. The increase in particle size decreased PE and DH due to a restricted access of solvents and enzymes to proteins. The thermal treatment induced a decrease in PE but did not modify DH. Heating improved legumin (alphaM) and convicilin pepsin hydrolyses but reduced the pea albumin 2 (PA2) hydrolysis. After pepsin and trypsin hydrolysis, only peptides from vicilin and lectin were identified by LC-MS/MS analyses, whatever the treatment.     

Echoguided closed commissurotomy for mitral valve stenosis in a dog

Surgical treatment of mitral stenosis (MS) usually consists of open mitral commissurotomy (MC) or percutaneous balloon MC, which require a cardiopulmonary bypass or transseptal approach, respectively. We describe here the first surgical management of congenital MS in a dog using a less invasive procedure, a surgical closed MC under direct echo guidance. A 5-year-old female Cairn terrier was referred for ascites, weakness, and marked exercise intolerance for 2 months, which was refractory to medical treatment. Diagnosis of severe MS associated with atrial fibrillation (AF) was confirmed by echo-Doppler examination and electrocardiography. Poor response to medical treatment suggested a corrective procedure on the valve was indicated. However, due to the cost and high mortality rate associated with cardiopulmonary bypass, a hybrid MC was recommended. A standard left intercostal thoracotomy was performed and three balloon valvuloplasty catheters of differing diameters were sequentially inserted through the left atrium under direct echo guidance. Transesophageal echocardiography revealed a 62% reduction in the pressure half-time compared to the pre-procedure. Thirteen months after surgery the dog is still doing well with resolution of ascites and a marked improvement of most echo-Doppler variables.     

Pythiosis in a dromedary camel (Camelus dromedarius).

A 4.5-yr-old male dromedary camel (Camelus dromedarius) was evaluated for a mass on the right side of the face. A complete blood count and blood chemistry revealed anemia and hypoproteinemia. Radiographs did not reveal bony involvement. The mass was resected and Pythium insidiosum was cultured. The camel was treated with an experimental immunotherapeutic vaccine and with sodium iodide and ceftiofur. The camel began to lose weight postoperatively and died 6 mo later. At necropsy, the camel was found to have gastritis of the third compartment of the stomach with intralesional hyphae of this oomycete pathogen.     

GC-MS quantification of suspected volatile allergens in fragrances. 2. Data treatment strategies and method performances

The performances of the GC-MS determination of suspected allergens in fragrance concentrates have been investigated. The limit of quantification was experimentally determined (10 mg/L), and the variability was investigated for three different data treatment strategies: (1) two columns and three quantification ions; (2) two columns and one quantification ion; and (3) one column and three quantification ions. The first strategy best minimizes the risk of determination bias due to coelutions. This risk was evaluated by calculating the probability of coeluting a suspected allergen with perfume constituents exhibiting ions in common. For hydroxycitronellal, when using a two-column strategy, this may statistically occur more than once every 36 analyses for one ion or once every 144 analyses for three ions in common.     

Bran Particle Size Influence on Pasta Microstructure,Water Distribution,and Sensory Properties

Whole wheat pasta offers improved nutritional value compared with regular pasta but lacks appeal to many consumers owing to its negative organoleptic properties, such as texture and taste. Various approaches have been studied to improve these properties in whole wheat products. Optimizing bran particle size showed its potential in noodles, but studies of its effects in pasta are scarce. Therefore, we produced spaghetti enriched with bran fractions similar in chemical composition but with varying median particle sizes of 90, 160, 370, and 440 µm. The effect of bran particles and their median size on dried and cooked pasta was studied by light microscopy and three‐dimensional magnetic resonance imaging. In general, bran particle size did not influence the macrostructure in cooked spaghetti. However, larger bran particles created a more heterogeneous microstructure in contrast to smaller particles and affected starch granule swelling. Sensory analysis indicated a preference for pasta containing smaller particles. Our results give new insight into the microstructural features responsible for the negative consumer appeal, and they could be used to guide future efforts in designing improved pasta formulations.     

Seasonal and spatial heterogeneities in host and vector abundances impact the spatiotemporal spread of bluetongue

Bluetongue (BT) can cause severe livestock losses and large direct and indirect costs for farmers. To propose targeted control strategies as alternative to massive vaccination, there is a need to better understand how BT virus spread in space and time according to local characteristics of host and vector populations. Our objective was to assess, using a modelling approach, how spatiotemporal heterogeneities in abundance and distribution of hosts and vectors impact the occurrence and amplitude of local and regional BT epidemics. We built a reaction–diffusion model accounting for the seasonality in vector abundance and the active dispersal of vectors. Because of the scale chosen, and movement restrictions imposed during epidemics, host movements and wind-induced passive vector movements were neglected. Four levels of complexity were addressed using a theoretical approach, from a homogeneous to a heterogeneous environment in abundance and distribution of hosts and vectors. These scenarios were illustrated using data on abundance and distribution of hosts and vectors in a real geographical area. We have shown that local epidemics can occur earlier and be larger in scale far from the primary case rather than close to it. Moreover, spatial heterogeneities in hosts and vectors delay the epidemic peak and decrease the infection prevalence. The results obtained on a real area confirmed those obtained on a theoretical domain. Although developed to represent BTV spatiotemporal spread, our model can be used to study other vector-borne diseases of animals with a local to regional spread by vector diffusion.     

Physical and land-cover variables influence ant functional groups and species diversity along elevational gradients

Of particular importance in shaping species assemblages is the spatial heterogeneity of the environment. The aim of our study was to investigate the influence of spatial heterogeneity and environmental complexity on the distribution of ant functional groups and species diversity along altitudinal gradients in a temperate ecosystem (Pyrenees Mountains). During three summers, we sampled 20 sites distributed across two Pyrenean valleys ranging in altitude from 1,009 to 2,339 m by using pitfall traps and hand collection. The environment around each sampling points was characterized by using both physical and land-cover variables. We then used a self-organizing map algorithm (SOM, neural network) to detect and characterize the relationship between the spatial distribution of ant functional groups, species diversity, and the variables measured. The use of SOM allowed us to reduce the apparent complexity of the environment to five clusters that highlighted two main gradients: an altitudinal gradient and a gradient of environmental closure. The composition of ant functional groups and species diversity changed along both of these gradients and was differently affected by environmental variables. The SOM also allowed us to validate the contours of most ant functional groups by highlighting the response of these groups to the environmental and land-cover variables.