Proteins and Carbohydrates from Red Seaweeds: Evidence for Beneficial Effects on Gut Function and Microbiota

Based on their composition, marine algae, and namely red seaweeds, are good potential functional foods. Intestinal mucosal barrier function refers to the capacity of the intestine to provide adequate containment of luminal microorganisms and molecules. Here, we will first outline the component of seaweeds and will summarize the effects of these on the regulation of mucosal barrier function. Special attention will be paid to unique components of red seaweeds: proteins and derived peptides (e.g., phycobiliproteins, glycoproteins that contain “cellulose binding domains”, phycolectins and the related mycosporine-like amino acids) together with polysaccharides (e.g., floridean starch and sulfated galactans, such as carrageenans, agarans and “dl-hybrid”) and minerals. These compounds have been shown to exert prebiotic effects, to regulate intestinal epithelial cell, macrophage and lymphocyte proliferation and differentiation and to modulate the immune response. Molecular mechanisms of action of peptides and polysaccharides are starting to be elucidated, and evidence indicating the involvement of epidermal growth factor receptor (EGFR), insulin-like growth factor receptor (IGFR), Toll-like receptors (TLR) and signal transduction pathways mediated by protein kinase B (PKB or AKT), nuclear factor-κB (NF-κB) and mitogen activated protein kinases (MAPK) will also be summarized. The need for further research is clear, but in vivo experiments point to an overall antiinflammatory effect of these algae, indicating that they can reinforce membrane barrier function.     

Effect of salicylic acid treatment on tomato plant physiology and tolerance to potato virus X infection

Salicylic acid (SA) is an inducer of systemic acquired resistance (SAR) and could be a potential candidate in the control of plant virus diseases. In this study we assayed under controlled conditions the potential effect of three doses of exogenous SA treatment on tomato plants infected with Potato virus X (PVX) and measured their effects on: different physiological parameters (gas exchange, stable isotopes, chlorophyll content), the activation of secondary metabolism, viral accumulation and induction of the expression of pathogenesis-related proteins (PRs) such as ß-1, 3-glucanase (PR2) and chitinase (PR3). SA treatment increased the expression of PR2, the activity of phenylalanine ammonia lyase (PAL) and the concentration of antioxidant compounds at 7 days post-treatment. Earlier expression of PR3 compared to PR2 was observed. SA treatment delayed the detection of PVX by ELISA in uninoculated leaves of mechanically infected tomato plants. Although the effect of PVX infection on physiological parameters was weak, moderate SA treatments showed enhanced photosynthesis, particularly for infected plants. The results obtained confirm that SA promotes major changes in the induction of resistance in tomato plants and suggest that treatment with exogenous SA could be considered to reduce the infections caused by PVX.     

Ultrastructural aspects of tomato leaves infected by Tomato torrado virus (ToTV) and co‐infected by other viruses

Optical and electron microscopy studies were carried out to investigate the cytopathology induced in tomato leaves infected by Tomato torrado virus (ToTV), a new picorna‐like virus associated with the ‘Torrado’ disease. Infected leaves, showing typical Torrado disease symptoms were surveyed in commercial greenhouses in the main tomato production areas of Spain. The effect of the co‐infection of ToTV with other viruses which commonly infect tomato crops was also studied. Ultra‐thin sections of ToTV‐infected tomato leaves did not show a strong cellular alteration. However, crystalline arrays of isometric virus‐like particles (VLPs) of 20–30 nm in the inclusion bodies were observed in phloem parenchyma cells of the infected tissues. Tissues co‐infected by ToTV and either Tomato chlorosis virus (ToCV) or Pepino mosaic virus (PepMV) presented more severe cellular alterations. The most deleterious consequences for tomato cells were found in triple infections of ToTV, PepMV and Tomato spotted wilt virus (TSWV), where characteristic cell wall overgrowth was distinguishable, together with a large amount of necrotic cells.     

Validation of a Commercial Enzyme Immunoassay for Detection of Clostridium difficile Toxins in Feces of Horses with Acute Diarrhea

Background: Clostridium difficile infection (CDI) is a recognized cause of colitis in the horse. Identification of its toxins is important for management of individual cases and for prevention of transmission and zoonosis. In humans, CDI diagnosis is performed with enzyme immunoassays, none of which have been validated for horses. Hypothesis/Objectives: (1) Establish which test for CDI diagnosis was more frequently used by diagnostic laboratories, (2) determine the identified test's performance, sensitivity, and specificity, and (3) validate its use in diarrheic horses. Animals: Samples were obtained from 72 horses presented with acute diarrhea and hospitalized at the Ontario Veterinary College, University of Guelph. Methods: A survey was conducted to establish which of the tests for CDI diagnosis in horses is most commonly used throughout North America. A questionnaire was sent to all laboratories registered in the Veterinary Infection Control Society and the American Association of Veterinary Laboratory Diagnosticians. The performance of the test was evaluated by comparison to a cell cytotoxicity assay (CTA), the accepted Gold Standard for C. difficile toxin detection. Results: The Techlab C. difficile Tox A/B II ELISA was the most frequently used test. Compared with the CTA, no significant difference was observed, and a good level of agreement (93%) was obtained. The diagnostic performance of the ELISA test was adequate (84% sensitivity and 96% specificity). Conclusions and Clinical Importance: Results demonstrate that the Techlab C. difficile Tox A/B II ELISA is a reliable, adequate, and practical tool for identification of C. difficile toxins in horse feces.     

The power of discourse: Hard lessons for traditional forest communities in the Amazon

In the contemporary Amazon, ‘discourse’ is increasingly a new means of exercising power, influencing local society and the ways in which natural resources are managed. As society becomes ever more complex, direct means of exercising power no longer enjoy the same legitimacy and efficacy. Discourses are instead now assuming a dominant role in defining governance regimes; the sense of what is correct and socially acceptable, and what is not. This is particularly relevant for the rapidly advancing development frontiers in the Amazon region, where local communities are coming into contact with external players highly interested in their forest resources. This study focuses on understanding how external discourses can restrict the Amazonian communities' options for using their forests, but also how communities can harness these discourses to achieve their own claims and objectives. Empirical evidence from four study areas in the Bolivian, Brazilian and Peruvian Amazon regions is used to show how discourses on sustainable forest management are moulding forestry governance. The conclusion shows that while the discourses used by loggers and development organisations are strongly influencing the way communities manage their forests, some communities are also successfully using these discourses in alliances with environmental organisations to achieve acknowledgment of their demands.     

Response of tubers of five potato cultivars to co-inoculation with US-1 and US-8 genotypes ofPhytophthora infestans

Summary The severity of late blight tuber rot in five potato cultivars (Green Mountain, Sebago, Dorita, AC Brador and Island Sunshine) resulting from inoculation with US-1/US-8 combinations of Canadian isolates ofPhytophthora infestans was evaluated. In addition, the potential for mixed (A1∶A2) inoculations to result in oospore formation was examined. In studies conducted in 1996 and 1997, cv. Dorita (and Island Sunshine in 1997) developed the least amount of surface or internal necrosis relative to the other cultivars following co-inoculation with US-1 and US-8 isolates ofP. infestans. Differences also were revealed among isolate combinations used for inoculation. The combination of a US-1 isolate from Prince Edward Island with a US-8 isolate from New Brunswick consistently produced the least amount of necrosis in tubers of the various cultivars. There was no evidence of oospore production in any of the tubers examined. AAFC Contribution No. 919     

Phenotypic segregation and relationships of agronomic traits in Monastrell × Syrah wine grape progeny

The aim of this work was to study the phenotypic segregation of different agronomic and fruit quality traits, and their relationships, in Monastrell × Syrah wine grape progeny. Twenty-two agronomic traits were evaluated and compared for three consecutive years in this progeny. The results show the phenotypic diversity existing in a cross between two different wine grape cultivars. Most of the phenological, productive, morphological, and enological parameters evaluated displayed continuous variation within the progeny, suggesting a polygenic inheritance. Some correlations between traits were detected by the Spearman correlation test, although high coefficients were not found for most of them. Cluster analysis of the progeny grouped the hybrids based on criteria with significance for wine grape breeding. Also, we investigated the relationship between the skin color and total content of anthocyanins with the VvmybA genotype, using the CAPS (Cleaved Amplified Polymorphic Sequence) marker 20D18CB9. The results show that hybrids with two copies of the functional color allele tend to have increased anthocyanins content. Based on this study, 14 genotypes were pre-selected from the breeding population for additional quality studies.     

Cryopreservation effects on the sperm quality of cachama blanca Piaractus brachypomus (Cuvier 1818)

The effects of straws volume, cryoprotectants and thawing temperatures were evaluated on the sperm quality of cachama blanca Piaractus brachypomus (Cuvier), an important Colombian fish species. Sexually mature fish were induced to ovulation or spermiation with a carp pituitary extract. A pool of suitable sperm samples was diluted in glucose, egg yolk, dimethyl sulphoxide (DMSO‐10%), methanol (MET‐10%) or ethylene glycol (ETG‐5%) and packed in 0.5, 2.5 or 5.0 mL straws and frozen in nitrogen vapour. The thawing process was performed in a 35 or an 80 °C water bath. The fertility was evaluated after 6 h post fertilization. The highest motility percentage (33 ± 3%) was observed with sperm cryopreserved with DMSO, packed in 5 mL straws and thawed at 35 °C. The treatments with DMSO and MET packed in 0.5 and 5.0 mL straws and thawed at 35 °C showed the highest fertility (higher than 71%) and the lowest fertility was obtained with MET‐2.5 mL (9 ± 5%). In all the treatments, a significant decrease in the sperm quality was observed at 80 °C. Sperm cryopreserved with DMSO‐10% or MET‐10%, packed in 2.5 or 5.0 mL straws are suitable to achieve acceptable fertilization and to fertilize high amounts of eggs.     

Partial Replacement of Fish Meal with Plant Protein Sources Singly and in Combination in Diets for Summer Flounder,Paralichthys dentatus

Soybean meal (SBM), corn gluten meal (CGM), and canola protein concentrate (CPC) as alternative protein sources to fish meal (FM) were individually evaluated for growth performance at 0, 20, 30, 40, and 50% replacement with amino acid (AA) supplementation using juvenile summer flounder, Paralichthys dentatus, in an 8‐wk feeding. Two‐way ANOVA indicated no significant main effect for plant protein source, but a significant main effect for replacement level. Comparison of the individual treatments revealed significant differences in weight gain (WG) between the FM treatment and 50% replacement level for all protein sources, as well as between the FM treatment and 30% replacement with CPC. Replacement of FM with SBM at 40% resulted in the least cost/kg WG. In a follow‐up study, a combination of SBM–CGM–CPC at 40% replacement was evaluated with and without AA, phytase (0.2%), or taurine (1%), versus FM and SBM (40% replacement of FM) with AA. The SBM–CGM–CPC diet with either AA or taurine provided a significantly better food conversion ratio and less cost/kg WG than the SBM diet, and the SBM–CGM–CPC diet with taurine provided a significantly better protein efficiency ratio than the SBM diet. On the basis of these results, more study of taurine in plant protein diets for summer flounder appears warranted.