Comparative study on antioxidant activity of lycopene (Z)-isomers in different assays

Several studies have implicated the potent antioxidant properties of lycopene. However, most of the studies used only the (all-E)-isomer. (Z)-Isomers of lycopene were found in substantial amounts in processed foods and in human tissues. In the present study, we investigated in vitro the antioxidant activity of (5Z)-, (9Z)-, and (13Z)-lycopene compared to the (all-E)-isomer. Additionally, prolycopene, the (7Z,9Z,7'Z,9'Z)-isomer found in tangerine tomatoes, was analyzed. No significant differences were found between the isomers in ferric reducing antioxidant power assay and in bleaching the radical cation of 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), both based on ET mechanisms. In contrast, scavenging activity against peroxyl radicals generated by thermal degradation of 2,2'-azobis(2-amidinopropane) (AAPH) was higher in the (Z)-isomers. (5Z)-Lycopene was most antioxidant in scavenging lipid peroxyl radicals, evaluated by analyzing the inhibition of MbFe(III) lipid peroxidation of linoleic acid in mildly acidic conditions (pH 5.8) in a micellar environment, modeling a possible antioxidant action in the gastric compartment.     

Leptospirosis in the western Indian Ocean islands: what is known so far?

In the past decade, leptospirosis has emerged as a major zoonosis with a worldwide distribution. The disease is caused by bacteria of the genus Leptospira. The western Indian Ocean includes more than one hundred tropical or subequatorial islands where leptospirosis constitutes a major public health problem. The clinical signs of the human disease are generally similar to an influenza-like syndrome, but acute forms of the disease are reported and mortality remains significant in this region. In animals, clinical forms are mainly asymptomatic but leptospirosis reduces the fertility of livestock, resulting in economic losses. The data available about human and animal leptospirosis in the western Indian Ocean islands are diverse: human leptospirosis has been extensively studied in Reunion Island, Mayotte, and the Seychelles, whereas the human clinical disease has never been described in Madagascar, Comoros, Mauritius, or Rodrigues, mainly because of the deficiency in appropriate medical and diagnostic structures. The rat is recognized as the major reservoir host for the bacteria on all islands, but recent data from Reunion Island indicates that almost all mammals can be a source of contamination. The incidence of leptospirosis in humans is highly seasonal, and linked to the rainy season, which is favorable for the environmental maintenance and transmission of the bacteria. The epidemiology of leptospirosis is fully island-dependent, related to the number of mammalian species, the origins of the introduced mammalian species, the relationships between humans and fauna, and environmental as well as cultural and socio-economic factors.     

Evaluation of a PCR kit for the detection ofErwinia carotovora subsp.atroseptica on potato tubers

Summary A PCR-based kit, Probelia^TM, for the detection ofErwinia carotovora subsp.atroseptica (Eca) on potatoes was evaluated at five laboratories in four countries. The kit is based on DNA-specific PCR amplification followed by detection of amplicons by hybridization to a peroxidase-labelled DNA probe in a microplate. Specificity of the PCR primers for Eca, regardless of serogroups, was confirmed by testing against 246 bacterial, fungal and plant species. Detection limits of the assay varied little between six Eca strains in pure cultures (1.3×10² to 1.5×10³ cells ml⁻¹). When Eca-free tuber peel extract from four cultivars was inoculated with known numbers of 15 Eca strains, detection limits were more variable (1.0×10¹ to 6.2×10³ cells ml⁻¹ peel extract), attributed probably to inconsistency in the recovery of DNA during extraction. When the PCR assay was compared with three current commercial Eca detection methods, using naturally contaminated tubers, results matched most closely those from viable counts on a selective medium, the most sensitive method (88%), followed by enrichment ELISA (72%) and last ELISA (30%), the least sensitive method.     

Pulse-labelling trees to study carbon allocation dynamics: a review of methods, current knowledge and future prospects

Pulse-labelling of trees with stable or radioactive carbon (C) isotopes offers the unique opportunity to trace the fate of labelled CO(2) into the tree and its release to the soil and the atmosphere. Thus, pulse-labelling enables the quantification of C partitioning in forests and the assessment of the role of partitioning in tree growth, resource acquisition and C sequestration. However, this is associated with challenges as regards the choice of a tracer, the methods of tracing labelled C in tree and soil compartments and the quantitative analysis of C dynamics. Based on data from 47 studies, the rate of transfer differs between broadleaved and coniferous species and decreases as temperature and soil water content decrease. Labelled C is rapidly transferred belowground-within a few days or less-and this transfer is slowed down by drought. Half-lives of labelled C in phloem sap (transfer pool) and in mature leaves (source organs) are short, while those of sink organs (growing tissues, seasonal storage) are longer. (13)C measurements in respiratory efflux at high temporal resolution provide the best estimate of the mean residence times of C in respiratory substrate pools, and the best basis for compartmental modelling. Seasonal C dynamics and allocation patterns indicate that sink strength variations are important drivers for C fluxes. We propose a conceptual model for temperate and boreal trees, which considers the use of recently assimilated C versus stored C. We recommend best practices for designing and analysing pulse-labelling experiments, and identify several topics which we consider of prime importance for future research on C allocation in trees: (i) whole-tree C source-sink relations, (ii) C allocation to secondary metabolism, (iii) responses to environmental change, (iv) effects of seasonality versus phenology in and across biomes, and (v) carbon-nitrogen interactions. Substantial progress is expected from emerging technologies, but the largest challenge remains to carry out in situ whole-tree labelling experiments on mature trees to improve our understanding of the environmental and physiological controls on C allocation.     

Changes in performance,blood parameters,humoral and cellular immune responses in weanling piglets exposed to low doses of aflatoxin

A feeding trial was conducted to evaluate the effect of aflatoxin (AF)-contaminated diets on growth and hematological and immunological parameters. Low doses of aflatoxins (140 and 280 ppb) were included in a corn-soybean diet provided for ad libitum consumption to 36 weanling piglets for a period of 4 wk. A "dose-related" decrease in weight gain was observed in treated animals. This effect was significant (P < 0.05) in the 280 ppb-treated group compared to the control group. Ingestion of AF-contaminated feed at either level had no effect on total red blood cell numbers or on their relative number of lymphocytes, monocytes, neutrophils, basophils, and eosinophils in blood. Likewise, AF did not alter globulin, albumins, or total protein concentrations in serum, nor did AF alter the expression of regulatory cytokines produced by either Th1 (IL-2) or Th2 (IL-4) lymphocyte subsets in phytohemagglutinin-stimulated blood samples. By contrast, AF had a biphasic effect on total white blood cell number; the low dose of AF (140 ppb) decreased the total number of white blood cells, whereas the high dose (280 ppb) had the opposite effect. Consumption of AF also increased the concentration of gamma-globulin in the serum. A reduced immune response induced by Mycoplasma agalactiae in the 280-ppb-treated group was also observed. Cytokine mRNA expression in phytohemagglutinin-stimulated blood cells indicated that AF decreased proinflammatory (IL-1beta, TNF-alpha) and increased anti-inflammatory (IL-10) cytokine mRNA expression. These results demonstrate that low doses of AF depress growth and alter many aspects of humoral and cellular immunity in pigs.     

Sensory and chemical changes in tomato sauces during storage

The present work aimed to identify the key odorants of tomato sauces responsible for the flavor change during storage. Products made from paste or canned tomatoes were stored at 25 and 40 degrees C. Sensory properties and quantification of the key odorants were measured and correlated. Significant sensory changes appeared after 1 and 3 months at 25 degrees C in the respective dice and paste sauces (p < 0.01). The dice sauce was characterized by a steep loss of the sensory quality during the early storage and then by identical changes within the same time span at 25 and 40 degrees C. In the paste sauce the sensory deterioration was slower than for the dice sauce and occurred more extensively at 40 degrees C than at 25 degrees C. Correlation between sensory and instrumental data revealed that the source of sensory changes should be (E,E)-deca-2,4-dienal in the dice sauce. The sensory change in the paste sauce could be due to acetaldehyde, methylpropanal, 3-methylbutanal, oct-1-en-3-one, 3-methylbutanoic acid, deca-2,4-dienal, 2-methoxyphenol, and beta-damascenone.     

Seed oil bodies from Gevuina avellana and Madia sativa

In this study, oil bodies (OBs) from Gevuina avellana (OBs-G) and Madia sativa (OBs-M) were isolated and characterized. Microscopic inspection revealed that the monolayer on OB-G was thinner compared to that on OB-M. Cytometric profiles regarding size, complexity, and staining for the two OB sources were similar. Fatty acid to protein mass ratio in both OBs was near 29, indicating high lipid enrichment. OBs-G and OBs-M showed a strong electrostatic repulsion over wide ranges of pH (5.5-9.5) and NaCl concentration (0-150 mM). Proteins displaying highly conserved sequences (steroleosins and aquaporins) in the plant kingdom were identified. The presence of oleosins was immunologically revealed using antibodies raised against Arabidopsis thaliana oleosins. OBs-G and OBs-M exhibited no significant cytotoxicity against the cells. This is the first report about the isolation and characterization of OBs-G and OBs-M, and this knowledge could be used for novel applications of these raw materials.     

Antimicrobial paper based on a soy protein isolate or modified starch coating including carvacrol and cinnamaldehyde

Soy protein isolates (SPI) and octenyl-succinate (OSA) modified starch were used as paper coating and inclusion matrices of two antimicrobial compounds: cinnamaldehyde and carvacrol. Antimicrobial compound losses from the coated papers were evaluated after the coating and drying process, and the two matrices demonstrated retention ability that depended on the compound nature and concentration. Whereas carvacrol losses ranged between 12 and 45%, cinnamaldehyde losses varied from 43 to 76%. The losses were always higher from OSA-starch-coated papers than from SPI-coated papers. During storage in accelerated conditions, at 30 degrees C and 60% relative humidity, carvacrol retention from coated papers was found to be similar whatever the coating matrices and the carvacrol rate. In contrast, the retention from SPI-coated papers was particularly high for the cinnamaldehyde concentration of 30% (w/w) compared to the lowest (10% w/w) or highest concentration (60% w/w). Compared to carvacrol, faster release was observed, particurlarly when OSA-starch was used. The antimicrobial properties of the coated papers were shown against Escherichia coli and Botrytis cinerea and explained by favorable conditions of total release of the antimicrobial agents.     

The role of ectomycorrhizal communities in forest ecosystem processes: New perspectives and emerging concepts

The fungal symbionts forming ectomycorrhizas, as well as their associated bacteria, benefit forest trees in a number of ways although the most important is enhancing soil nutrient mobilization and uptake. This is reciprocated by the allocation of carbohydrates by the tree to the fungus through the root interface, making the relationship a mutualistic association. Many field observations suggest that ectomycorrhizal fungi contribute to a number of key ecosystem functions such as carbon cycling, nutrient mobilization from soil organic matter, nutrient mobilization from soil minerals, and linking trees through common mycorrhizal networks. Until now, it has been very difficult to study trees and their fungal associates in forest ecosystems and most of the work on ECM functioning has been done in laboratory or nursery conditions. In this review with discuss the possibility of working at another scale, in forest settings. Numerous new techniques are emerging that makes possible the in situ study of the functional diversity of ectomycorrhizal communities. This approach should help to integrate developing research on the functional ecology of ectomycorrhizas and their associated bacteria with the potential implications of such research for managing the effects of climate change on forests.     

Similar pattern of iNOS expression, NO production and cytokine response in genetic and vaccination-acquired resistance to Marek's disease

NO is produced by macrophages through activation of the inducible enzyme NOS and its production is triggered as an antiviral and antitumoral immune mechanism. Replication of Marek's disease herpes virus (MDV) is inhibited by NO in vitro. MDV induces T-lymphomas in the chicken and a genetic resistance to tumor development has been linked to the B21 major histocompatibility complex. During the first initial week of viral replication after inoculation of the highly virulent RB-1B MDV strain, histocompatible B21/B21 chickens developed strong iNOS expression and NO production capacity in the spleen, in parallel with strong systemic NO production in the serum. Comparable NO response was not seen with the vaccinal strain HVT. In contrast, reduction in spleen macrophage number and delay in iNOS gene expression was observed in genetically susceptible B13/B13 chickens after MDV infection, in addition to suppression of IFN-gamma-inducible NO production. However, vaccination with HVT 3 days before RB-1B inoculation restored strong iNOS gene expression in the spleen 1 week later and inducible NO production 3 weeks later. Following the pattern of iNOS gene expression, early strong expression of cytokines with powerful iNOS-inducing activity such as IFN-gamma and CC chemokines from the MIP family (MIP-1beta, K203) was observed in genetic resistance and resistance acquired after vaccination with HVT. In conclusion, resistance to MDV appeared preferentially linked in both types of resistance to the early establishment of cytokine induction characteristic of a Th1 immune response, thus favoring the development of an early and strong NO response.