Rust fungi (Pucciniales) are a diverse group of plant pathogens in natural and agricultural systems. They pose ongoing threats to the diversity of native flora and cause annual crop yield losses. Agricultural rusts are predominantly managed with fungicides and breeding for resistance, but new control strategies are needed on non‐agricultural plants and in fragile ecosystems. RNA interference (RNAi) induced by exogenous double‐stranded RNA (dsRNA) has promise as a sustainable approach for managing plant‐pathogenic fungi, including rust fungi. We investigated the mechanisms and impact of exogenous dsRNA on rust fungi through in vitro and whole‐plant assays using two species as models, Austropuccinia psidii (the cause of myrtle rust) and Coleosporium plumeriae (the cause of frangipani rust) . In vitro, dsRNA either associates externally or is internalized by urediniospores during the early stages of germination. The impact of dsRNA on rust infection architecture was examined on artificial leaf surfaces. dsRNA targeting predicted essential genes significantly reduced germination and inhibited development of infection structures, namely appressoria and penetration pegs. Exogenous dsRNA sprayed onto 1‐year‐old trees significantly reduced myrtle rust symptoms . Furthermore, we used comparative genomics to assess the wide‐scale amenability of dsRNA to control rust fungi. We sequenced genomes of six species of rust fungi, including three new families (Araucariomyceaceae, Phragmidiaceae, and Skierkaceae) and identified key genes of the RNAi pathway across 15 species in eight families of Pucciniales. Together, these findings indicate that dsRNA targeting essential genes has potential for broad‐use management of rust fungi across natural and agricultural systems.

Key features of advanced ovarian cancer include metastasis via cell clusters in the abdominal cavity and increased chemoresistance. Resveratrol and derivatives of resveratrol have been shown to have antitumour properties. The purpose of this study was to investigate the effect of resveratrol and acetyl-resveratrol on 3D cell aggregates of ovarian cancer, and establish if NF-κB signalling may be a potential target. Poly-HEMA coated wells were used to produce 3D aggregates of two ovarian cancer cell lines, SKOV-3 and OVCAR-5. The aggregates were exposed to 10, 20 or 30 μM resveratrol or acetyl-resveratrol for 2, 4 or 6 days. Cell growth and metabolism were measured then ELISA, western blot and immunofluorescence were utilised to evaluate VEGF, IL-8 and NF-κB levels. Resveratrol and acetyl-resveratrol reduced cell growth and metabolism of SKOV-3 aggregates in a dose- and time-dependent manner. After 6 days all three doses of both compounds inhibited cell growth. This growth inhibition correlated with the attenuated secretion of VEGF and a decrease of NF-κB protein levels. Conversely, the secretion of IL-8 increased with treatment. The effects of the compounds were limited in OVCAR-5 cell clusters. The results suggest that resveratrol and its derivative acetyl-resveratrol may inhibit in vitro 3D cell growth of certain subtypes of ovarian cancer, and growth restriction may be associated with the secretion of VEGF under the control of the NF-κB protein.

Oomycetes and fungi are microorganisms whose pathogenic (invasive) growth can cause diseases that are responsible for significant ecological and economic losses. Such growth requires the generation of a protrusive force, the magnitude and direction of which involves a balance between turgor pressure and localised yielding of the cell wall and the cytoskeleton. To study invasive growth in individual hyphae we have developed a lab-on-a-chip platform with integrated force-sensors based on elastomeric polydimethylsiloxane (PDMS) micro-pillars. With this platform we are able to measure protrusive force (both magnitude and direction) and hyphal morphology. To show the usefulness of the platform, the oomycete Achlya bisexualis was inoculated and grown on a chip. Growth of individual hyphae into a micro-pillar revealed a maximum total force of 10 μN at the hyphal tip. The chips had no discernible effect on hyphal growth rates, but hyphae were slightly thinner in the channels on the chips compared to those on agar plates. When the hyphae contacted the pillars tip extension decreased while tip width increased. A. bisexualis hyphae were observed to reorient their growth direction if they were not able to bend and effectively grow over the pillars. Estimates of the pressure exerted on a pillar were 0.09 MPa, which given earlier measures of turgor of 0.65 MPa would indicate low compliance of the cell wall. The platform is adaptable to numerous cells and organisms that exhibit tip-growth. It provides a useful tool to begin to unravel the molecular mechanisms that underlie the generation of a protrusive force.

This paper describes the design, fabrication and characterisation of a novel monolithic lab-on-a-chip (LOC) platform combining the trapping and germination of individual zoospores of the oomycete Achlya bisexualis with elastomeric micropillar-based protrusive force sensing. The oomycetes are of significant interest due to their pathogenic capabilities, which can have profound ecological and economic impacts. Zoospore encystment and germination via a germ tube play a key role in their pathogenicity. Our platform enables the study of these processes at a single cell level through hydrodynamic trapping of zoospores and their individual compartmentalization via normally closed pneumatic membrane microvalves. Valve geometry was optimized and media exchange characterized during dynamic valve operations to enhance the capture-to-growth ratio. We demonstrate germination of A. bisexualis zoospores on the platform and report three distinct germination patterns. Once germinated, germ tubes grew down growth channels towards single elastomeric micropillars. Tracking of pillar movement allowed for the measurement of microNewton range protrusive forces imparted by the tips of the germ tubes. Results indicate that the forces generated by the germ tubes are smaller than those exerted by mature hyphae. Through the use of parallel traps, channels and pillars on the same device, the platform enables high-throughput screening (HTS) of zoospores and their generation of protrusive force, an essential component of their infective capability. Due to its versatility, it will also allow for the screening of naturally bioactive compounds and the development of new biocontrol strategies for oomycetes, and morphologically similar fungal infections, as an alternative to agrochemicals.

Vulvovaginal candidiasis (VVC) and recurrent vulvovaginal candidiasis (RVVC) affect millions of women and are typically treated with azoles. We know little about azole susceptibility of Candida species from VVC versus RVVC patients, and nothing about African isolates. We have investigated the susceptibility of Candida isolates from Ghana to fluconazole, itraconazole and/or voriconazole. The percentage of Candida albicans isolates showing susceptibility was significantly lower in RVVC than VVC patients. Isolates of Candida parapsilosis and Candida tropicalis showed a similar trend. For Candida glabrata there was no observed difference. The data indicate a decreased susceptibility in selected Candida species from RVVC patients.