Lipolytic activity in free and immobilized cells of Phoma glomerata

The lipolytic activity of free and immobilized whole cells of the pathogenic fungus Phoma glomerata was demonstrated, and several properties of the lipase involved were determined. Free fungal cells and small pieces of immobilized cells, prepared by spontaneous colonization on a solid surface or entrapped in calcium alginate, were incubated with triolein in buffered medium. Different incubation conditions were assayed to optimize the reaction, to determine the effects of heating and time on stability of the immobilized preparations and the time course of the reactions. Although the enzyme cleaves all ester bonds of triolein, it shows some preference for the outer bonds. An optimal pH of 7.5–8.0, optimal temperature of 45°C for free and 50°C for immobilized cell preparations, the necessity for substrate emulsifiers, and reaction independence from calcium and magnesium were demonstrated. Results suggest that immobilized whole cells of P. glomerata would be a suitable tool to study its lipid physiology and to explore further the possible biotechnological use of its lipase activity.     

Biological activity of the shrubBoscia senegalensis (PERS.) LAM. ex Poir. (Capparaceae) on stored grain insects

Biological activity of leaves, fruits and extract of the African shrubBoscia senegalensis (PERS.) LAM. ex Poir. was evaluated against five stored-grain insects. When added to cowpeas at 2–4% (w/w), fresh ground fruits and leaves caused 80–100% mortality inCallosobruchus maculants (F.) adults and significantly reduced both emergence and damage of the F₁ progeny. Acetone fruit extract exhibited a potent fumigant effect onProstephanus truncatus Horn, C.maculatus, andSitotroga cerealella OLIV.; with LT₅₀ values of 3.8, 2.3, and below 1.5 hr, respectively. LC₅₀ determination forB. senegalensis fruits and leaves as well as pure methylisothiocyanate (MITC) onTribolium castaneum HERBST,Sitophilus zeamais MOTSCH. andC. maculatus showed a differential response of the insects to plant parts or MITC. Quantitative dosage ofBoscia active components and LC₅₀ values obtained for the plant tissues, compared to those of pure molecules, indicate that the biological activity ofB. senegalensis is due to the liberation of MITC from a glucosinolate precursor glucocapparin contained inBoscia fruits and leaves.     

A generalised three-dimensional tethered-nodule model for auxetic materials

Models for the nano/micro-structural deformation and mechanical properties of auxetic materials (i.e. materials with a negative Poisson’s ratio) have been previously developed. However, most of these models have been two-dimensional, were usually designed specifically to describe some particular class of auxetic materials, and generally only described the behaviour of one particular plane whilst completely ignoring the out-of-plane behaviour of the material. A three-dimensional model has been developed which can be applied to several classes of auxetic materials, including microporous expanded polymers such as e-PTFE, e-UHMWPE and e-PA, body-centered cubic metals and foams. It is generalised that its underlying structure is not specific to a lengthscale or material as the previous list shows. The new model offers a better insight into the underlying principles behind the observed auxetic behaviour and offers a significant improvement in the agreement of the models with existing experimental data. It is shown that there are geometric limitations to the number of planes that can simultanesously display auxetic behaviour. This has ramifications on the design of ordered auxetic materials.     

Effects of probiotic,prebiotic and synbiotic follow‐up infant formulas on large intestine morphology and bone mineralisation in rats

The effects of powder functional follow‐up infant formulas on the morphology of the large intestine and the bone mineral content in rats were investigated. Infant formulas were supplemented with probiotics (Bifidobacterium bifidum and Bifidobacterium longum), prebiotics (galacto‐oligosaccharides (4′‐GOS) at 12, 50 and 100 g kg^?1) or synbiotics (bifidobacteria and 4′‐GOS) and administered to seven groups of weanling rats over 30 days. After sacrificing the animals, the caecum and colon were removed and the luminal content pH and the crypt depth and cell density within the epithelial layer were measured. Results showed that groups fed synbiotic diets had significantly (P < 0.05) lower caecal and colonic content pH values compared with the control group. However, no test diet significantly modified the crypt depth or cell density in the caecum. In contrast, all seven test diets significantly increased (P < 0.05) the crypt depth in both the proximal and distal portions of the colon. There was a high correlation (Pearson correlation coefficient 0.870) between caecal and colonic content pH values. On the other hand, colonic content pH was negatively correlated with crypt depth in both the proximal and distal colon and with cell density in the distal colon. The authors previously reported increases in calcium, magnesium and phosphorus absorption using the same infant formulas. In the present study it was concluded that the increase in calcium absorption took place in the distal colon whereas magnesium absorption increased in both the proximal and distal colon, and their contents (especially that of calcium) increased in both the femur and tibia. Copyright © 2007 Society of Chemical Industry     

Variation of chemical composition data of agricultural and forest fibrous by-products as determined by the two detergent systems of analysis

The growing use of agricultural and forest by-products as ruminant feed, and of the detergent system to determine their feeding value, makes it of interest to compare direct and sequential detergent analyses in order to examine the differences between them and the extent of accuracy. The chemical composition of cereal straws (oat, barley, rye, wheat, maize) and legume straws (fenugreek, pea-grass, lupin, pea and bean), grapevines, fenugreek bagasse and poplar bark was determined by applying both methods. Lignin (measured as permanganate lignin) and cellulose (measured as sulphuric acid cellulose) showed the greatest differences (2·0 and 3·2%, respectively). Tannins (1·5% of DM) and cell-wall protein (2·0% of DM) could account for the discrepancy between both routines of analysis and for that between both lignin procedures.     

Production of reduced-calorie grape juice jelly with gellan, xanthan and locust bean gums: sensory and objective analysis of texture

 The production of reduced-calorie grape juice jellies with gellan, xanthan and locust bean gums (LBG) was studied. Twenty formulations of grape juice jelly were prepared according to a second-order composite rotatable design (with six central points). Response surface methodology (RSM) was used to optimise jelly formulation using as independent variables: total sugar content, ranging from 14 to 46°Brix; and total gum concentration ranging from 0.30 to 0.70% (w/v), with the proportion of gums in the mixture xanthan:LBG:gellan ranging from 5:5:90 up to 45:45:10. The processing temperature used was 90°C for complete solubilisation of gums. The dependent variables were objective measures of texture and a parameter obtained from sensory analysis, the overall balance (B), which represents the overall evaluation of the jelly. The resulting polynomial equation (R ² = 0.929) revealed that a jelly produced with white grape juice, total sugar with sucrose equal to 39.3°Brix, and, 0.54% (w/v) of total gum added in the proportions of: 1:1:1.7 (gellan:xanthan:LBG) had a maximum value of B. The sensory-optimised jelly was objectively characterised for texture and the model was tested. The texture characteristics, i.e. gel hardness, cohesiveness and springiness, were found to be similar to those of a reference product, a previously developed reduced-calorie grape juice jelly with low methoxyl pectin. Received: 12 June 1997 / Revised version: 21 August 1997     

Modelling Salmonella concentration throughout the pork supply chain by considering growth and survival in fluctuating conditions of temperature, pH and a(w)

We aim to predict the population density of Salmonella spp. through the pork supply chain under dynamic environmental conditions (pH, a(w) and temperature) that fluctuate from growth to survival/slow inactivation. To do this, the dependence of the probability of growth, and of the growth and inactivation rate on the temperature, pH and a(w) were modelled. Probabilistic and kinetic measurements, i.e. growth and survival curves, were collected from the ComBase database (www.combase.cc). Conditions at which selected data used to fit the models were generated covered wide ranges that are relevant to the pork supply chain. Probabilistic and kinetic models were combined to give predictions on the concentration of Salmonella spp. at any stage of the pork supply chain under fluctuating pH, a(w) and/or temperature. Models were implemented in a user-friendly computing tool freely available from http://www.ifr.ac.uk/safety/SalmonellaPredictions/. This program provides estimates on the population dynamics of Salmonella spp. at any stage of the pork supply chain and its predictive performance has been validated in several pork products.     

Folate fortification of white and whole-grain bread by adding Swiss chard and spinach. Acceptability by consumers

The aim of this work was to study the effect of bread-making on the content of endogenous folate of white and whole-grain bread fortified with either Swiss chard or spinach at 20 g/100 g and 40 g/100 g measured by HPLC (H4-folate and 5-CH3-H4-folate); and to assess the sensory acceptability of folate-fortified breads compared to non-fortified breads. The fortification of breads with 20 g/100 g and 40 g/100 g vegetables significantly (p < 0.001) increased the total folate content (from 19.9 to 57.9 μg/100 g in white bread and from 37.4 to 75.5 μg/100 g in whole-grain bread). Moreover, 40 g/100 g Swiss chard- and spinach-fortified breads obtained higher scores in overall acceptability than 20 g/100 g fortified or control bread for both white and whole-grain breads. The consumption of two servings (56 g each) per day of 40 g/100 g fortified bread would meet the daily folate requirements by 14.3–21.8% in adults and 9.6–14.5% in some special states like women of child-bearing age.     

A Step Forward in Breast Cancer Research: From a Natural-Like Experimental Model to a Preliminary Photothermal Approach

Breast cancer is one of the most frequently diagnosed malignancies and common causes of cancer death in women. Recent studies suggest that environmental exposures to certain chemicals, such as 7,12-Dimethylbenzanthracene (DMBA), a chemical present in tobacco, may increase the risk of developing breast cancer later in life. The first-line treatments for breast cancer (surgery, chemotherapy or a combination of both) are generally invasive and frequently associated with severe side effects and high comorbidity. Consequently, novel approaches are strongly required to find more natural-like experimental models that better reflect the tumors’ etiology, physiopathology and response to treatments, as well as to find more targeted, efficient and minimally invasive treatments. This study proposes the development and an in deep biological characterization of an experimental model using DMBA-tumor-induction in Sprague-Dawley female rats. Moreover, a photothermal therapy approach using a near-infrared laser coupled with gold nanoparticles was preliminarily assessed. The gold nanoparticles were functionalized with Epidermal Growth Factor, and their physicochemical properties and in vitro effects were characterized. DMBA proved to be a very good and selective inductor of breast cancer, with 100% incidence and inducing an average of 4.7 tumors per animal. Epigenetic analysis showed that tumors classified with worst prognosis were hypomethylated. The tumor-induced rats were then subjected to a preliminary treatment using functionalized gold nanoparticles and its activation by laser (650–900 nm). The treatment outcomes presented very promising alterations in terms of tumor histology, confirming the presence of necrosis in most of the cases. Although this study revealed encouraging results as a breast cancer therapy, it is important to define tumor eligibility and specific efficiency criteria to further assess its application in breast cancer treatment on other species.