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A lectin from the green Venezuelan marine alga Caulerpa serrulata was extracted with phosphate buffered saline (PBS) using cold steeping infusion (CSI) and by grinding with liquid nitrogen (GLN). The proteins were precipitated using solid ammonium sulfate. Both the crude extracts and ammonium sulfate precipitated proteins were tested for hemagglutinins using native and papain-treated human red blood cell suspensions in isotonic saline solution. Purification of lectins was achieved using affinity chromatography-sugar-epoxy-sepharose 6B and molecular weight was assessed by size exclusion chromatography using Bio-gel ® P-100 and SDS-PAGE with 2-mercaptoethanol. IEF-urea 8M was also evaluated. Using CSI it was shown that the marine alga released hemagglutinating compounds into the solutions; the same hemagglutinating compounds were also obtained by GLN. Ammonium sulfate precipitated proteins exhibited agglutinating activity against native and papain-treated human red blood cells. Temperature and EDTA were shown to affect dramatically the lectin activity towards red blood cells. A lectin was purified efficiently and the molecular weight calculated as approximately 78,000 Daltons. The CSI technique demonstrated that the alga could be returned to an active metabolic state by immersion in a simple buffer after having been kept dormant by freezing at-20ºC for long periods. It was also shown that the alga was releasing bioactive compounds into the solutions and, therefore, this procedure is being suggested as a good, gentle, non-disruptive extraction technique and we postulate CSI as a possible bioreactor for the continuous production of bioactive compounds from green marine algae.

The green alga Ulva fasciata Delile (Ulvaceae), after thawing from storage at-20 o C, has been used to study the in vivo biosynthesis and release of lectins. The alga was made to resume viable growth by immersion in a PBS buffer, pH 7.4, containing 0.01% w/v sodium azide and irradiating with a halophosphate lamp. The growing alga readily took up 14 C leucine, when this was added to the buffer, as seen by a decrease in a sample count rate of ~ 8000 cpm over a period of twenty minutes. The transfer of the radioactivity fed algae into fresh PBS buffer resulted in 14 C labeled proteins being subsequently released into solution. As well as observing changes in levels of radioactivity, the release of proteins was also monitored by UV absorption at 280 nm. Both techniques indicated an initial steady release over the first twelve hours, followed by a slower approach to a plateau value. Transfer of the algae that had undergone an initial period of protein release into a subsequent second and third volume of fresh PBS buffer produced similar UV absorption profiles, but the total quantities of material released were reduced. Identification of the released proteins was obtained from their ability to agglutinate red blood cells, which was inhibited by L-fucose, and their electrophoretic mobilities when compared with earlier isolated samples of the U. fasciata lectin. The reference lectin was obtained by affinity chromatography, following the selective precipitation of the water soluble algal proteins with ammonium sulfate. We postulate that the observed release profiles support the previously suggested concept that lectins have the ability to function as protection agents for living marine algae.

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Background: Raw vegetables have been considered vehicles of enteroparasites. South American countries are among the most important exporters of fresh vegetables; Ecuador has tropical climates and soils rich in organic matter that allow it to harvest throughout the year for sale to different countries. The aim of the study was to assess the occurrence of the parasitic contamination of fruits, vegetables and leafy greens grown in an agricultural area of the Ecuadorian Andes. Methods: A field study, cross-sectional, snowball sampling was conducted on 1,416 samples (516 fruits, 488 vegetables, and 412 leafy greens). Each sample were washed with water, and the resulting solution after removing the vegetables, was subjected to 24-hour sedimentation. The concentrated sediment underwent microscopic analysis. Results: Parasites were detected in 63.4% of the samples, leafy greens were the most contaminated (76.9%) (P<0.0001), (vegetables 67.8% and fruit 48.4%), of these, cabbage (100%), onions (84%) and strawberries (60.2%) were the most contaminated. Protozoa were more frequent (49.6%) than helminths (15.5%) (P<0.0001). Blastocystis sp. (33.5%) was the highest, followed by Eimeria spp. (26.3%), Entamoeba spp. (10.3%), Giardia spp. (8.3%), Balantidium spp. (6.9%); Cryptosporidium spp. (6.6%), Cyclospora spp. (4.4%), Cystoisospora spp. (0.5%); Strongylida (15.5%) and Ascaris spp. (0.4%). Conclusion: The consumption of fruits, vegetables, and leafy greens from these crops is a possible source of infection to humans and animals in this area or in nonendemic areas where these products are marketed. This study establishes the need for strict hygienic measures in growing; this will be properly achieved by the treatment of the soil, manure and water used for cultivation.