Low-Molecular-Weight Seaweed-Derived Polysaccharides Lead to Increased Faecal Bulk but Do Not Alter Human Gut Health Markers

Seaweeds are potentially sustainable crops and are receiving significant interest because of their rich bioactive compound content; including fatty acids, polyphenols, carotenoids, and complex polysaccharides. However, there is little information on the in vivo effects on gut health of the polysaccharides and their low-molecular-weight derivatives. Herein, we describe the first investigation into the prebiotic potential of low-molecular-weight polysaccharides (LMWPs) derived from alginate and agar in order to validate their in vivo efficacy. We conducted a randomized; placebo-controlled trial testing the impact of alginate and agar LWMPs on faecal weight and other markers of gut health and on composition of gut microbiota. We show that these LMWPs led to significantly increased faecal bulk (20–30%). Analysis of gut microbiome composition by sequencing indicated no significant changes attributable to treatment at the phylum and family level, although FISH analysis showed an increase in Faecalibacterium prausnitzii in subjects consuming agar LMWP. Sequence analysis of gut bacteria corroborated with the FISH data, indicating that alginate and agar LWMPs do not alter human gut microbiome health markers. Crucially, our findings suggest an urgent need for robust and rigorous human in vivo testing—in particular, using refined seaweed extracts

Molecular biology methods for detection and identification of cryptosporidium species in feces, water, and shellfish

Techniques based on nucleic acid amplification have proven to be essential for the detection and epidemiological tracking of members of the genus Cryptosporidium. This gastrointestinal protozoan parasite cannot be routinely cultivated and it has an extremely low infectious dose, possibly below 100 oocysts. As Cryptosporidium is an important pathogen, particularly in immuno-compromised hosts, there is a pressing need to employ sensitive and discriminatory systems to monitor the organism. A number of fairly standard target genes have been assessed as detection targets, including 18S rRNA, microsatellites, and heat-shock (stress) proteins. As our knowledge of the biology of the organism increases, and as the full genome information becomes available, the choice of target may change. Genes encoding parasite-specific surface proteins (gp60, TRAP-C2, COWP) have already been examined. Much of the effort expended in molecular diagnostics of Cryptosporidium has been directed toward developing robust nucleic acid extraction methods. These are vital in order to recover amplifiable DNA from environments where small numbers of oocysts, often fewer than 100, may exist. Methodology based on adaptation of commercial kits has been developed and successfully employed to recover amplifiable DNA directly from water, food (particularly seafood), and fecal samples

In vitro inhibition of epithelial cell invasion by Aeromonas hydrophila and Vibrio species by fish Aeromonas hydrophila major adhesin

10.1046/j.1365-2761.1998.00102.xJournal of Fish Diseases214273-280JFID

Actin rearrangements accompanying Aeromonas hydrophila entry into cultured fish cells

10.1046/j.1365-2761.1998.00076.xJournal of Fish Diseases21155-65JFID