Cadmium is a highly toxic heavy metal for biological systems. Cupriavidus metallidurans CH34 is a model strain for heavy metal resistance and bioremediation. The aim of this study was to determine the role of the c-di-GMP pathway in the C. metallidurans CH34 response to cadmium in both planktonic and biofilm cells. Increasing cadmium concentrations correlates with an inhibition of biofilm formation and EPS production in C. metallidurans cells. Planktonic and biofilm cells showed similar tolerance to cadmium. During exposure to cadmium an acute decrease of c-di-GMP levels in planktonic and biofilm cells was observed. Transcription analysis by RT-qPCR showed that cadmium induced in planktonic cells and strongly induced in biofilm cells the expression of the urf2 gene and the mercuric reductase encoding merA gene, which belong to the Tn501/Tn21 mer operon. After exposure to cadmium the cadA gene involved in cadmium resistance was equally upregulated in both lifestyles. Bioinformatic analysis and null mutant complementation assays indicated that the protein encoded by the urf2 gene is a functional phosphodiesterase involved in the c-di-GMP metabolism. We propose to rename the urf2 gene as mrp gene for metal regulated phosphodiesterase. An increase of the second messenger c-di-GMP content by the heterologous expression of the constitutively active diguanylate cyclase PleD* correlated with an increase in biofilm formation and cadmium susceptibility. These results indicate that the response to cadmium in C. metallidurans CH34 involves a decrease in c-di-GMP content that inhibits the biofilm lifestyle.

Drug resistance in tumor cells is a significant roadblock in the clinical management of advanced or recurrent diseases in endometrial cancers. As a part of the tumor-stromal ecosystem, tumor cells are ecologically connected to the cancer-associated fibroblasts (CAFs), which form contributory elements of the tumor microenvironment (TME). We recently reported a novel model of patient-derived CAF-based 2-cell Hybrid Co-Culture (HyCC) to evaluate CAFs' role in developing drug resistance and understanding personalized tumor cell-CAF dialogue. Using our 2-cell HyCC model of patient-derived endometrial CAFs, we present data to demonstrate the direct counter-inhibitory effect of CAFs to combinations of cytotoxic and targeted drugs in developing drug resistance. CAFs derived from resected endometrial tumor samples were first passage-wise characterized before and after freeze-thaw for their positive and negative CAF markers expression pattern. Paclitaxel and its combination with copanlisib, TAK228, lenvatinib, and trametinib were used to test the 3D clonogenic growth of endometrial AN3CA cells on endometrial CAFs. We demonstrate that CAF-mediated resistance to antitumor drugs occurs via direct and indirect contact with CAFs in HyCC. Our data established the strength of the 2-cell HyCC model of patient-derived CAFs in solid tumors and provided a model of resistance to antitumor drugs tailored on a patient-to-patient basis.

Fungi are ubiquitous and metabolically versatile. Their dispersion has important scientific, environmental, health, and economic implications. They can be dispersed through the air by the aerosolization of near surfaces or transported from distant sources. Here, we tested the contribution of local (scale of meters) versus regional (kilometers) sources by analyzing airborne fungal community by ITS sequencing around a copper mine in the North of Chile. The mine was the regional source, whereas soil and vegetal detritus were the local sources at each point. The airborne community was highly homogeneous in ca. 2,000 km2, impeding the detection of regional or local contributions. Ascomycota was the dominant phylum in the three communities. Soil and vegetal detritus communities had lower alpha-diversity, but some taxa had abundance patterns related to the distance to the mine and altitude. On the contrary, the air was compositionally even and unrelated to environmental or spatial factors, except for altitude. The presence of plant pathogens in the air suggests that other distant sources contribute to this region's airborne fungal community and reinforces the complexity of tracking the sources of air microbial communities in a real world where several natural and human activities coexist.