Cyanobacteria comprise a phylum defined by the capacity for oxygenic photosynthesis. Members of this phylum are frequently motile as well. Strains that display gliding or twitching motility across semisolid surfaces are powered by a conserved type IV pilus system (T4P). Among the filamentous, heterocyst-forming cyanobacteria, motility is usually confined to specialized filaments known as hormogonia, and requires the deposition of an associated hormogonium polysaccharide (HPS). The genes involved in assembly and export of HPS are largely undefined, and it has been hypothesized that HPS exits the outer membrane via an atypical T4P-driven mechanism. Here, several novel hps loci, primarily encoding glycosyl transferases, are identified. Mutational analysis demonstrates that the majority of these genes are essential for both motility and production of HPS. Notably, most mutant strains accumulate wild-type cellular levels of the major pilin PilA, but not extracellular PilA, indicating dysregulation of the T4P motors, and, therefore, a regulatory interaction between HPS assembly and T4P activity. A co-occurrence analysis of Hps orthologs among cyanobacteria identified an extended set of putative Hps proteins comprising most components of a Wzx/ Wzy-type polysaccharide synthesis and export system. This implies that HPS may be secreted through a more canonical pathway, rather than a T4P-mediated mechanism.

Trichomoniasis in humans, caused by the protozoal parasite Trichomonas vaginalis, is the most common non-viral sexually transmitted disease, while Tritrichomonas foetus causes trichomonosis, an infection of the gastrointestinal tract and diarrhea in farm animals and domesticated cats. As part of an effort to determine the inhibitory effects of plant-based extracts and pure compounds, seven commercially available cherry tomato varieties were hand-peeled, freeze-dried, and pounded into powders. The anti-trichomonad inhibitory activities of these peel powders at 0.02% concentration determined using an in vitro cell assay varied widely from 0.0% to 66.7% against T. vaginalis G3 (human); from 0.9% to 66.8% for T. foetus C1 (feline); and from 0.0% to 81.3% for T. foetus D1 (bovine). The organic Solanum lycopersicum var. cerasiforme (D) peels were the most active against all three trichomonads, inhibiting 52.2% (G3), 66.8% (C1), and 81.3% (D1). Additional assays showed that none of the powders inhibited the growth of foodborne pathogenic bacteria, pathogenic fungi, or non-pathogenic lactobacilli. Tomato peel and pomace powders with high content of described biologically active compounds could serve as functional food and feed additives that might help overcome adverse effects of wide-ranging diseases and complement the treatment of parasites with the anti-trichomonad drug metronidazole.