A series of ferrocenyl- and aryl-functionalised organosilane thiosemicarbazone compounds was obtained via a nucleophilic substitution reaction with an amine-terminated organosilane. The thiosemicarbazone (TSC) ligands were further reacted with either a ruthenium dimer [(η(6-i)PrC6H4Me)Ru(μ-Cl)Cl]2 or a rhodium dimer [(Cp*)Rh(μ-Cl)Cl]2 to yield a series of cationic mono- and binuclear complexes. The thiosemicarbazone ligands, as well as their metal complexes, were characterised using NMR and IR spectroscopy, and mass spectrometry. The molecular structure of the binuclear ruthenium(ii) complex was determined by single-crystal X-ray diffraction analysis. The thiosemicarbazones and their complexes were evaluated for their in vitro antiplasmodial activities against the chloroquine-sensitive (NF54) and chloroquine-resistant (Dd2) Plasmodium falciparum strains, displaying activities in the low micromolar range. Selected compounds were screened for potential β-haematin inhibition activity, and it was found that two Rh(iii) complexes exhibited moderate to good inhibition. Furthermore, the compounds were screened for their antitrichomonal activities against the G3 Trichomonas vaginalis strain, revealing a higher percentage of growth inhibition for the ruthenium and rhodium complexes over their corresponding ligand.

Microbial eukaryotes (protists) are important components of terrestrial and aquatic environments, as well as animal and human microbiomes. Their relationships with metazoa range from mutualistic to parasitic and zoonotic (i.e., transmissible between humans and animals). Despite their ecological importance, our knowledge of protists in urban environments lags behind that of bacteria, largely due to a lack of experimentally validated high-throughput protocols that produce accurate estimates of protist diversity while minimizing non-protist DNA representation. We optimized protocols for detecting zoonotic protists in raw sewage samples, with a focus on trichomonad taxa. First, we investigated the utility of two commonly used variable regions of the 18S rRNA marker gene, V4 and V9, by amplifying and Sanger sequencing 23 different eukaryotic species, including 16 protist species such as Cryptosporidium parvum, Giardia intestinalis, Toxoplasma gondii, and species of trichomonad. Next, we optimized wet-lab methods for sample processing and Illumina sequencing of both regions from raw sewage collected from a private apartment building in New York City. Our results show that both regions are effective at identifying several zoonotic protists that may be present in sewage. A combination of small extractions (1 mL volumes) performed on the same day as sample collection, and the incorporation of a vertebrate blocking primer, is ideal to detect protist taxa of interest and combat the effects of metazoan DNA. We expect that the robust, standardized methods presented in our workflow will be applicable to investigations of protists in other environmental samples, and will help facilitate large-scale investigations of protistan diversity.Electronic supplementary materialThe online version of this article (doi:10.1007/s00248-017-0996-9) contains supplementary material, which is available to authorized users.

Isonicotinyl and pyrazinyl ferrocenyl-derived complexes were prepared using various hydrazides and ferrocenyl aldehydes. Three heterobimetallic complexes were also synthesized from the Schiff base-derived isonicotinyl ferrocene complex using various platinum group metal dimers based on ruthenium, rhodium and iridium. All complexes were evaluated in vitro for antimycobacterial and antiparasitic activity. Against Mycobacterium tuberculosis H37Rv, the platinum group metal complexes showed glycerol-dependent antimycobacterial activity. The antiplasmodial activities against the NF54 chloroquine-sensitive strain of Plasmodium falciparum of some compounds were moderate, while some complexes also showed promising activity against Trichomonas vaginalis. Incorporation of the ferrocenyl-salicylaldimine moiety resulted in enhanced antimicrobial activity compared to the non-ferrocenyl compound in some cases. The bimetallic iridium-ferrocene isonicotinyl complex exhibited superior antitrichomonal activity relative to its organic counterpart, isoniazid. Furthermore, all these compounds, when screened on several normal flora bacteria of humans, showed no effect on the microbiome, emphasizing the selection of these compounds for these pathogens. The promising antimicrobial activities of the complexes thus supports incorporation of ferrocene as part of existing antimicrobial therapies in order to alter their biological activities favorably.