Table of Contents

Abstract: Bloodsucking arthropods are a rich source of salivary molecules (sialogenins) which inhibit platelet aggregation, neutrophil function and angiogenesis. Here we review the literature on salivary disintegrins and their targets. Disintegrins were first discovered in snake venoms, and were instrumental in our understanding of integrin function and also for the development of anti-thrombotic drugs. In hematophagous animals, most disintegrins described so far have been discovered in the salivary gland of ticks and leeches. A limited number have also been found in hookworms and horseflies, and none identified in mosquitoes or sand flies. The vast majority of salivary disintegrins reported display a RGD motif and were described as platelet aggregation inhibitors, and few others as negative modulator of neutrophil or endothelial cell functions. This notably low number of reported disintegrins is certainly an underestimation of the actual complexity of this family of proteins in hematophagous secretions. Therefore an algorithm was created in order to identify the tripeptide motifs RGD, KGD, VGD, MLD, KTS, RTS, WGD, or RED (flanked by cysteines) in sialogenins deposited in GenBank database. The search included sequences from various blood-sucking animals such as ticks (e.g., Ixodes sp., Argas sp., Rhipicephalus sp., Amblyomma sp.), tabanids (e.g., Tabanus sp.), bugs (e.g., Triatoma sp., Rhodnius prolixus), mosquitoes (e.g., Anopheles sp., Aedes sp., Culex sp.), sand flies (e.g., Lutzomyia sp., Phlebotomus sp.), leeches (e.g., Macrobdella sp., Placobdella sp.) and worms (e.g., Ancylostoma sp.). This approach allowed the identification of a remarkably high number of novel putative sialogenins with tripeptide motifs typical of disintegrins (>450 sequences) whose biological activity remains to be verified. This database is accessible online as a hyperlinked worksheet and displays biochemical, taxonomic, and gene ontology aspects for each putative disintegrin. It is also freely available for download (right click with the mouse) at links http://exon.niaid.nih.gov/transcriptome/RGD/RGD-Peps-WEB.xlsx (web version) and http://exon.niaid.nih.gov/transcriptome/RGD/RGD-sialogenins.zip (stand alone version).

Abstract: A divalent cation-independent lectin—HOL-18, with cytotoxic activity against leukemia cells, was purified from a demosponge, Halichondria okadai. HOL-18 is a 72 kDa tetrameric lectin that consists of four non-covalently bonded 18 kDa subunits. Hemagglutination activity of the lectin was strongly inhibited by chitotriose (GlcNAcβ1-4GlcNAcβ1-4GlcNAc), fetuin and mucins from porcine stomach and bovine submaxillary gland. Lectin activity was stable at pH 4–12 and temperatures lower than 60 °C. Frontal affinity chromatography with 16 types of pyridylaminated oligosaccharides indicated that the lectin had an affinity for N-linked complex-type and sphingolipid-type oligosaccharides with N-acetylated hexosamines and neuramic acid at the non-reducing termini. The lectin killed Jurkat leukemia T cells and K562 erythroleukemia cells in a dose- and carbohydrate-dependent manner.

Abstract: A phosphatase inhibition assay for detection of okadaic acid (OA) toxins in shellfish, OkaTest, was single laboratory validated according to international recognized guidelines (AOAC, EURACHEM). Special emphasis was placed on the ruggedness of the method and stability of the components. All reagents were stable for more than 6 months and the method was highly robust under normal laboratory conditions. The limit of detection and quantification were 44 and 56 µg/kg, respectively; both below the European legal limit of 160 µg/kg. The repeatability was evaluated with 2 naturally contaminated samples. The relative standard deviation (RSD) calculated was 1.4% at a level of 276 µg/kg and 3.9% at 124 µg/kg. Intermediate precision was estimated by testing 10 different samples (mussel and scallop) on three different days and ranged between 2.4 and 9.5%. The IC₅₀ values of the phosphatase used in this assay were determined for OA (1.2 nM), DTX-1 (1.6 nM) and DTX-2 (1.2 nM). The accuracy of the method was estimated by recovery testing for OA (mussel, 78–101%; king scallop, 98–114%), DTX-1 (king scallop, 79–102%) and DTX-2 (king scallop, 93%). Finally, the method was qualitatively compared to the mouse bioassay and LC-MS/MS.

Abstract: The aim of the present study was to evaluate the effect of long-term cyanidin 3-O-β-D-glucoside (C3G) and/or Ochratoxin A (OTA)-exposure on dimethylarginine dimethylamino hydrolase/nitric oxide synthase (DDAH/NOS) pathway in rats. The experiments were performed in rats supplemented with C3G (1 g/kg feed), OTA (200 ppb), and OTA + C3G. After 4 weeks of daily treatment, liver and kidneys were processed for eNOS, iNOS and DDAH-1 Western blotting, nitrite levels evaluation and DDAH activity determination. Results show that OTA is able to induce iNOS both in kidney and liver, whereas OTA is able to induce eNOS and DDAH-1 overexpression and DDAH activation only in kidney, resulting in increased nitrite levels. In kidney of OTA + C3G fed rats, iNOS, eNOS and DDAH-1 expression were less pronounced compared with those observed in the OTA-treated group. Coherent with the decreased iNOS, eNOS and DDAH-1 expression a decrease in nitrite levels and DDAH activity was observed in the OTA + C3G group. Results demonstrate that C3G is able to counteract the deleterious effects of chronic consumption of OTA and also suggest a possible involvement of iNOS-eNOS-DDAH impairment in OTA nephrocarcinogenity.

Abstract: Ochratoxin A (OTA) is a mycotoxin commonly present in cereals, grapes, coffee, spices, and cocoa. Even though the main objective of the food and feed chain processors and distributors is to avoid the extended contamination of plant-derived foods and animal feeds with mycotoxins, until now, complete OTA removal from foods and feedstuffs is not feasible. Prevention through pre-harvest management is the best method for controlling mycotoxin contamination. However, in the case that the contamination occurs after this stage, the hazards associated with OTA must be managed through post-harvest strategies. Due to the increasing number of fungal strains resistant to chemical fungicides and the impact of these pesticides on the environment and human health, maximum levels of chemical residues have been regulated in many products. Alternative methods are necessary to substitute or complement treatments with fungicides to control fungi under field or storage conditions. Yeasts are considered one of the most potent biocontrol agents due to their biology and non-toxic properties. Epiphytic yeasts are the major component of the microbial community on the surface of grape berries and they are evolutionarily adapted to this ecological niche. Nowadays, several yeast species included in different genera are considered as potential biocontrol agents to control both, growth of ochratoxigenic Aspergillus species and OTA accumulation.

Abstract: On the market since 1996, genetically modified plants expressing an insecticidal toxin (Cry toxin stemmed from Bacillus thuringiensis) target several lepidopteran and coleopteran pests. In this study, we assessed the impact of two varieties of Bt maize producing different toxins (Cry1Ab or Cry1Fa, respectively) on the biology of a storage pest: Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae). The Indianmeal moths were susceptible to both toxins but showed an escape behavior only from Cry1Fa. The weight of females issued from larvae reared on Cry1Ab increased with increasing toxin concentration, but adults of both sexes reared on Cry1Fa had decreased weight. Both toxins increased development time from egg to adult regardless of sex and had no impact on the male adult lifespan. Finally, we recorded a time lag between metamorphosis from the non-Bt and the Bt diets, which increased proportionally to Cry concentration in the Bt diet.