Codeine dysregulates ribosome biogenesis in Escherichia coli with DNA double-strand breaks to chart path to new classes of antibiotics.

Aim: A bacterial genetics-guided approach was utilized for the discovery of new compounds affecting bacterial genome stability. Materials & methods: Fungal extracts and fractions were tested for genome instability-mediated antibacterial activity. Interaction assays and RT-qPCR were used to identify compounds that boost the activity of sub-minimum inhibitory concentration streptomycin and obtain insights on the molecular mechanisms of the primary hit compound, respectively. Results: Several extracts and fractions caused bacterial genome instability. Codeine, in synergy with streptomycin, regulates double-strand break (DSB) repair and causes bacterial ribosome dysfunction in the absence of DSBs, and dysregulation of ribosome biogenesis in a DSB-dependent manner. Conclusion: This study demonstrates a potential viable strategy that we are exploring for the discovery of new chemical entities with activities against Escherichia coli and other bacterial pathogens.

Drug discovery research in Ghana, challenges, current efforts, and the way forward.

We have a long-term vision to develop drug discovery research capacity within Ghana, to tackle unmet medical needs in Ghana and the wider West African region. However, there are several issues and challenges that need to be overcome to enable this vision, including training, human resource, equipment, infrastructure, procurement, and logistics. We discuss these challenges from the context of Ghana in this review. An important development is the universities and research centres within Ghana working together to address some of these challenges. Therefore, while there is a long way to go to fully accomplish our vision, there are encouraging signs.

Transcriptomic analysis of marine endophytic fungi extract identifies highly enriched anti-fungal fractions targeting cancer pathways in HepG2 cell lines.

BACKGROUND: Marine endophytic fungi (MEF) are good sources of structurally unique and biologically active secondary metabolites. Due to the increase in antimicrobial resistance, the secondary metabolites from MEF ought to be fully explored to identify candidates which could serve as lead compounds for novel drug development. These secondary metabolites might also be useful for development of new cancer drugs. In this study, ethyl acetate extracts from marine endophytic fungal cultures were tested for their antifungal activity and anticancer properties against C. albicans and the human liver cancer cell line HepG2, respectively. The highly enriched fractions were also analyzed by high performance liquid chromatography coupled with high resolution mass spectrometry (HPLC-HRMS) and their effect on the HepG2 cells was assessed via transcriptomics and with a proliferation assay. RESULTS: We demonstrated that the fractions could reduce proliferation in HepG2 cells. The detailed transcriptome analysis revealed regulation of several cancer- and metabolism-related pathways and gene ontologies. The down-regulated pathways included, cell cycle, p53 signaling, DNA replication, sphingolipid metabolism and drug metabolism by cytochrome P450. The upregulated pathways included HIF-1 signaling, focal adhesion, necroptosis and transcriptional mis-regulation of cancer. Furthermore, a protein interaction network was constructed based on the 26 proteins distinguishing the three treatment conditions from the untreated cells. This network was composed of central functional components associated with metabolism and cancer such as TNF, MAPK, TRIM21 and one component contained APP. CONCLUSIONS: The purified fractions from MEF investigated in this study showed antifungal activity against C. albicans and S. cerevisiae alone or both and reduced proliferation of the human liver cancer cell line HepG2 implicating regulation of several cancer- and metabolism-related pathways. The data from this study could be instrumental in identifying new pathways associated with liver cancer anti-proliferative processes which can be used for the development of novel antifungal and anti-cancer drugs.

Electrochemical Response of Saccharomyces cerevisiae Corresponds to Cell Viability upon Exposure to Dioclea reflexa Seed Extracts and Antifungal Drugs.

Dioclea reflexa bioactive compounds have been shown to contain antioxidant properties. The extracts from the same plant are used in traditional medical practices to treat various diseases with impressive outcomes. In this study, ionic mobility in Saccharomyces cerevisiae cells in the presence of D. reflexa seed extracts was monitored using electrochemical detection methods to link cell death to ionic imbalance. Cells treated with ethanol, methanol, and water extracts were studied using cyclic voltammetry and cell counting to correlate electrochemical behavior and cell viability, respectively. The results were compared with cells treated with pore-forming Amphotericin b (Amp b), as well as Fluconazole (Flu) and the antimicrobial drug Rifampicin (Rif). The D. reflexa seed water extract (SWE) revealed higher anodic peak current with 58% cell death. Seed methanol extract (SME) and seed ethanol extract (SEE) recorded 31% and 22% cell death, respectively. Among the three control drugs, Flu revealed the highest cell death of about 64%, whereas Amp b and Rif exhibited cell deaths of 35% and 16%, respectively, after 8 h of cell growth. It was observed that similar to SWE, there was an increase in the anodic peak current in the presence of different concentrations of Amp b, which also correlated with enhanced cell death. It was concluded from this observation that Amp b and SWE might follow similar mechanisms to inhibit cell growth. Thus, the individual bioactive compounds from the water extracts of D. reflexa seeds could further be purified and tested to validate their potential therapeutic application. The strategy to link electrochemical behavior to biochemical responses could be a simple, fast, and robust screening technique for new drug targets and to understand the mechanism of action of such drugs against disease models.

Wood-decaying fungi found in Southern Ghana: A potential source of new anti-infective compounds.

Background: Discovery of bioactive natural products are instrumental for development of novel antibiotics. The discovery and development of natural products such as penicillin represented a major milestone in the treatment of bacterial infections. Currently, many antibiotics have lost their relevance in clinics due to the emergence of drug-resistant microbial pathogens. Hence, there is the need for continuous search of new compounds endowed with potent antimicrobial activity. Methods: In this study, wood-decaying fungi (WDF) from Ghana were explored for their potential as sources of novel antimicrobial compounds with intent of expanding the effort into a drug discovery programme in the near future. Extracts from cultures of 54 morphologically distinct WDF isolates were analyzed for the presence of antimicrobial agents. Results: The extracts from 40 out of the 54 WDF isolates exhibited significant antimicrobial activity against either Staphylococcus aureus, Escherichia coli or Candida albicans. Fractionation of these bioactive extracts, followed by bioassay of the organic fractions obtained, indicate that extracts exhibiting antimicrobial activity against more than one of the three test organisms could be attributed to the presence of different bioactive compounds. Analysis of the composition of the extracts revealed that terpenes were predominant. Conclusions: This study suggests that a significant proportion of WDF in Ghana produce antimicrobial compounds which could be potential sources of novel anti-infective agents and support the plans of developing a drug discovery programme in Ghana based on the fermentation of WDF.

Elr-type proteins protect Xenopus Dead end mRNA from miR-18-mediated clearance in the soma.

Segregation of the future germ line defines a crucial cell fate decision during animal development. In Xenopus, germ cells are specified by inheritance of vegetally localized maternal determinants, including a group of specific mRNAs. Here, we show that the vegetal localization elements (LE) of Xenopus Dead end (XDE) and of several other germ-line-specific, vegetally localized transcripts mediate germ cell-specific stabilization and somatic clearance of microinjected reporter mRNA in Xenopus embryos. The part of XDE-LE critical for somatic RNA clearance exhibits homology to zebrafish nanos1 and appears to be targeted by Xenopus miR-18 for somatic mRNA clearance. Xenopus Elr-type proteins of the vegetal localization complex can alleviate somatic RNA clearance of microinjected XDE-LE and endogenous XDE mRNA. ElrB1 synergizes with Xenopus Dead end protein in the stabilization of XDE-LE mRNA. Taken together, our findings unveil a functional link of vegetal mRNA localization and the protection of germ-line mRNAs from somatic clearance.