Tests for the depolymerization of polyacrylamides as a potential source of acrylamide in heated foods

This study was conducted to test the possibility that polyacrylamides used in agriculture may contribute to acrylamide formation in heated foods by thermal depolymerization. Two samples of polyacrylamide with low molecular weights of 1.5 and 10 kDa were used to test for in-chain and end-chain depolymerization. They were added as aqueous solutions to filter paper for heating in a drying/dry environment and added to a cooking oil for heating in a fatty environment. The heating conditions were 175 degrees C for 15 and 30 min, respectively. Both regimens were tested in the absence and presence of the redox-active metal ions Fe(III) and Cu(II), and all tests were conducted without the exclusion of atmospheric oxygen. There was no evidence of any significant depolymerization of polyacrylamide to free acrylamide monomer, <0.04%. In fact, residual levels of acrylamide present already in the low molecular weight polymers were seen to fall by 50-80% on heating. Consequently, it is concluded that even if polyacrylamides were to contaminate agricultural crops and foods derived therefrom (which itself is an unproven suggestion), there is no evidence that the polymers would depolymerize on heating of the food to form acrylamide in any significant amount.     

Marine Fish Larvae Feeding: Formulated Diets or Live Prey?

In the rearing of larval marine fish, any diet that reduces dependance on live prey production is of technical and economic interest. Weaning juveniles with a completely developed digestive tract to a conventional diet, (i.e., "late weaning") can be successful in any marine fish species. For example, weaning one-month-old sea bass (20 mg) to the study's reference diet, Sevbar, resulted in over 85% survival (40% from hatching) and 1.25 g fish at day 90 (at 19 C)
In contrast, "early weaning" of larvae to special microdiets during the first month is still difficult. The best way to reduce live prey utilization in sea bass is to wean larvae at about 3–4 mg in size (day 20). If weaning could be accomplished 15 days earlier, Artemia savings could be as high as 80%. However, this introduces risks relative to growth retardation (30% weight loss) and lower juvenile quality, including greater size variability and skeletal abnormalities. Similar results have been obtained with commercial microparticles (Fry Feed Kyowa) and experimental microbound diets (MBD) made from raw materials (alginate MBD) or preferably from freeze-dried protein sources (zein MBD).
Total replacement of live prey is still impossible in marine fish. Sea bass larvae fed formulated diets exclusively from first feeding (0.3 mg larval wet weight), or even from their second week of life onwards, exhibited low survival and poor growth. Better results can be obtained when formulated diets are used in combination with live prey from first feeding, although the optimal ratio of live prey to formulated diet is still to be specified.     

Genetic variation in <Emphasis Type="Italic">Pinus taeda</Emphasis> wood properties predicted using non-destructive techniques

• Background   

Tree breeders have been reluctant to include wood traits in tree improvement programs owing to logistic difficulties and the cost associated with the assessing the traits.     

Cellular Impact of Metal Trace Elements in Terricolous Lichen Diploschistes muscorum (Scop.) R. Sant. – Identification of Oxidative Stress Biomarkers

The purpose of this research is to present toxic effects of some heavy metals (cadmium, lead and zinc) on lichen physiology. In the North of France, those metals are concentrated for example in industrial polluted soils near metallurgic plants and waste dumps. Our investigations were conducted on Diploschistes muscorum (Scop.) R. Sant, a terricolous lichen growing on previously quoted soils as well as on non-contaminated ones. Different stress parameters were investigated as potassium leakage – which is related to the loss of membrane integrity – and oxidative stress through following parameters: malondialdehyde (MDA), glutathione (GSH) and superoxide dismutase (SOD). It seems, therefore, that heavy metals induce oxidative stress in this lichen, in which we found membrane damage and enhancement of SOD activity and GSH concentrations. With regard to very high concentrations of Cd, Pb and Zn, a resistance involving antioxidant mechanisms limits the expected damage. Those mechanisms involve GSH, SOD as well as secondary metabolites, which have this resistance property. This study is a first step of investigation to use – in the future– physiological parameters as tool for environment assessment.     

Anatomy, physiology and pathology of the amniotic and allantoic compartments in the sheep and cow

In both cows and sheep the allantoic fluid is confined to 2 sacs connected by a flattened isthmus, one in the non-pregnant horn and one in the upper part of the pregnant horn. The chorion encloses the amniotic and allantoic compartments, forming the amniochorion and chorioallantois, respectively. In the last third of gestation the compositions of both amniotic and allantoic fluids differ substantially from each other and from those of foetal urine, and maternal and foetal plasma. There is less variation in composition than in volume for a given gestational age. Abnormalities of volume are more common in cows than sheep, and hydrallantois is more common than hydramnois. Data obtained from both physiological experiments and pathological cases suggest that the foetal membranes play an important role in the regulation of composition and volume of foetal fluids. Evidence is presented that the permeability of the membranes to various solutes, as well as their capacity to produce and respond to a number of hormones, can affect the foetal fluid composition and/or volume. Progesterone, oestrogens and prolactin are some of the hormones known to affect foetal fluids. Foetal adrenal insufficiency has been associated with hydramnios implying a lack of hormones from this gland in this disease. The changes in allantoic fluid composition from normal to that closely resembling maternal/foetal extracellular fluid, in hydrallantois, suggests an alteration of membrane function as an aetiology and the continued production of fluid, after removal of the foetus in some cases, favours this hypothesis.     

Deposits of the mildew fungicide binapacryl on the leaves of apple trees of differing sizes after mist blower spraying

Trials in 1975 and 1976 showed that deposit levels of the fungicide binapacryl, on the leaves of bush trees of Cox's Orange Pippin (Cox) after mist blower spraying, varied inversely with tree spread. Deposit levels were measured on young mildew-susceptible leaves from a well-sprayed zone around the periphery of the tree canopy at a height of 1.5 m. Low deposit levels in large, dense trees were associated with poor mildew control. Leaves from the smallest trees had deposit levels considerably greater than those found for larger trees (in another nearby orchard) which had adequate mildew control. Fungicide deposit levels on leaves from up to five different zones of trees of three different sizes (the largest trees were of the variety Bramley's Seedling) were measured in 1977. The smallest trees had significantly higher deposit levels than the larger trees in the lower centre and lower outside zones of the trees, whereas both orchards of Cox had the same (commercially acceptable) level of mildew infection at the end of the season. Leaves from zones less accessible to spray had lowerdeposit levels than those nearer the sprayer.     

Weaned piglets display low gastrointestinal digestion of pea (Pisum sativum L.) lectin and pea albumin 2

A study was conducted to investigate the biochemistry of digestion of field pea (Pisum sativum L.) albumins and globulins in the stomach and along the small intestine of weaned piglets with a particular emphasis on the respective roles of these compartments in pea protein digestion. Twenty-four piglets were weaned at 28 d of age. They were allocated to 2 diets (control and pea) and 3 slaughter times (3, 6, or 9 h after the last meal) in a 2 x3 factorial arrangement of treatments in a randomized complete block design. Pea flour provided 30% of total dietary protein in the pea diet. The diets were fed for 2 wk after weaning. After slaughter, gastrointestinal tract (GIT) compartments were weighed, digesta were collected, and pH was measured. Digesta from the stomach and cranial, middle, and caudal small intestine (SI) were extracted for soluble proteins and analyzed for specific pea proteins using SDS-PAGE, immunoblotting, and mass spectrometry. Tissue weight of the whole GIT (P = 0.015), cecum (P <0.001), and colon (P <0.001) was greater in the pea diet. Digesta pH in the stomach and caudal SI was lower (P = 0.02) in the pea diet than the control diet. In the stomach, vicilin, lectin, and pea albumin 2 were not digested, whereas legumin was only partly digested. Legumin and vicilin were totally digested in the SI in less than 3 h. A resistant peptide of 15 kDa located at the N-terminus of pea albumin 2 was transiently detected at 3 h. A protein band at 20 kDa was consistently identified as lectin. It was present in high intensity in intestinal digesta of pea-fed piglets at all times after the meal compared with those fed the control diet (P <0.001). Various proteins of, presumably, endogenous origin displayed differential digestion patterns between the control and the pea-fed piglets (P<0.05). In conclusion, differences in digestion between specific pea proteins were observed along the GIT of piglets. They could be partly explained by differences in protein digestion in the stomach.     

Differential expression of homing receptors and vascular addressins in tonsils and draining lymph nodes: Effect of Brucella infection in sheep

The differential expression of homing receptors (HR) and complementary vascular addressins was studied in T and B lymphocytes from ovine tonsils and draining lymph nodes (LN) in uninfected and Brucella melitensis-infected sheep. In uninfected sheep, CD4+CD25+ T cells expressed proportionally more L-selectin and beta1 integrin than beta7 integrin in pharyngeal and palatine tonsils and in parotid LN (PLN), retropharyngeal LN (RLN) and the peripheral prescapular LN (PSLN). In contrast, memory CD4+CD45RA- T cells expressed an equivalent proportion of the three HR in PLN and PSLN, whereas beta1 and beta7 integrins were proportionally more expressed than L-selectin in pharyngeal tonsil. beta7 integrin was proportionally more expressed than beta1 integrin or L-selectin in palatine tonsils, RLN and the mucosal mesenteric LN (MLN). beta1 integrin was proportionally more expressed in IgG+ and IgA+ cells than beta7 integrin and L-selectin in tonsils, PLN and RLN. The main endothelial addressin expressed on venules in both pharyngeal and palatine tonsils, the PLN and RLN, as well as in the PSLN, was the peripheral PNAd, while in the MLN it was MAdCAM-1. Conjunctival infection by Brucella resulted in an increase of CD4+CD25+ and CD4+CD45RA- T cell subsets, which was associated to modifications of HR expression. CD4+CD45RA- T cells expressed proportionally more beta1 and beta7 integrins than L-selectin in regional PLN and RLN, but also in PSLN. The infection induced an increase of IgG+ and IgA+ cell percentages expressing beta1 integrin in all LN, and also beta7 integrin in the RLN. PNAd continued to be expressed on venules of tonsils and draining LN after Brucella infection, and MAdCAM-1 was also weakly expressed on RLN venules. These results suggest that lymphocyte trafficking through tonsils and draining LN could involve L-selectin/PNAd interactions, as well as beta1 or beta7 integrin, possibly in interaction with VCAM-1 or MAdCAM-1. The homing of antigen-specific lymphocytes in these tissues could be modulated after conjunctival infection with Brucella, which induces the recruitment of lymphocytes that express both beta1 and/or beta7 integrin in regional and more distant LN.