Mesophilic to thermophilic conditions in codigestion of sewage sludge and OFMSW: evaluation of effluent stability using dynamic respirometric index (DRI) and biochemical methane potential (BMP).

The paper deals with the change from the mesophilic to thermophilic conditions in the codigestion process applied to secondary sludge from a biological nutrients removal (BNR) together with the organic fraction of municipal solid waste (OFMSW) or biowaste. The first part of the study was carried out at pilot scale in a 0.38 nr' pilot scale plant, in order to evaluate the process behaviour during short-time meso-thermo passage and the relative yield increase, in the second part, the same set of operational conditions was applied to a full scale 2000 m 3 digester: both pilot and full scale trials evidenced the same behaviour and results. The thermophilic range of temperature showed a general increase of performance of about 50% in terms of biogas yields and allowed for a better stabilisation of the effluent (digestate). In order to evaluate this aspect, both the aerobic and anaerobic rate of stability was evaluated: the effective rate of stabilisation of the digested material by means of aerobic (Dynamic Respirometric Index), and anaerobic batch tests (Biochemical Methane Potential) was determined. Preliminary tests on the effluents originated from three plants showed a DRI lower than 1000 mgO 2/kgVSh which is the minimum value required for a stable compost following the Italian regulation system, and an average SGP of 0,15-0,30 m 3/kgVS which demonstrated a partial conversion of the organic matter into biogas

The &ITPlasmodium falciparum &ITtranscriptome in severe malaria reveals altered expression of genes involved in important processes including surface antigen-encoding &ITvar &ITgenes

Within the human host, the malaria parasite Plasmodium falciparum is exposed to multiple selection pressures. The host environment changes dramatically in severe malaria, but the extent to which the parasite responds to-or is selected by-this environment remains unclear. From previous studies, the parasites that cause severe malaria appear to increase expression of a restricted but poorly defined subset of the PfEMP1 variant, surface antigens. PfEMP1s are major targets of protective immunity. Here, we used RNA sequencing (RNAseq) to analyse gene expression in 44 parasite isolates that caused severe and uncomplicated malaria in Papuan patients. The transcriptomes of 19 parasite isolates associated with severe malaria indicated that these parasites had decreased glycolysis without activation of compensatory pathways; altered chromatin structure and probably transcriptional regulation through decreased histone methylation; reduced surface expression of PfEMP1; and down-regulated expression of multiple chaperone proteins. Our RNAseq also identified novel associations between disease severity and PfEMP1 transcripts, domains, and smaller sequence segments and also confirmed all previously reported associations between expressed PfEMP1 sequences and severe disease. These findings will inform efforts to identify vaccine targets for severe malaria and also indicate how parasites adapt to-or are selected by-the host environment in severe malaria

The Plasmodium falciparum transcriptome in severe malaria reveals altered expression of genes involved in important processes including surface antigen-encoding var genes

Within the human host, the malaria parasite Plasmodium falciparum is exposed to multiple selection pressures. The host environment changes dramatically in severe malaria, but the extent to which the parasite responds to-or is selected by-this environment remains unclear. From previous studies, the parasites that cause severe malaria appear to increase expression of a restricted but poorly defined subset of the PfEMP1 variant, surface antigens. PfEMP1s are major targets of protective immunity. Here, we used RNA sequencing (RNAseq) to analyse gene expression in 44 parasite isolates that caused severe and uncomplicated malaria in Papuan patients. The transcriptomes of 19 parasite isolates associated with severe malaria indicated that these parasites had decreased glycolysis without activation of compensatory pathways; altered chromatin structure and probably transcriptional regulation through decreased histone methylation; reduced surface expression of PfEMP1; and down-regulated expression of multiple chaperone proteins. Our RNAseq also identified novel associations between disease severity and PfEMP1 transcripts, domains, and smaller sequence segments and also confirmed all previously reported associations between expressed PfEMP1 sequences and severe disease. These findings will inform efforts to identify vaccine targets for severe malaria and also indicate how parasites adapt to-or are selected by-the host environment in severe malaria

Carriage of stx2a differentiates clinical and bovine-biased strains of Escherichia coli O157

Shiga toxin (Stx) are cardinal virulence factors of enterohemorrhagic E. coli O157:H7 (EHEC O157). The gene content and genomic insertion sites of Stx-associated bacteriophages differentiate clinical genotypes of EHEC O157 (CG, typical of clinical isolates) from bovine-biased genotypes (BBG, rarely identified among clinical isolates). This project was designed to identify bacteriophage-mediated differences that may affect the virulence of CG and BBG. Stx-associated bacteriophage differences were identified by whole genome optical scans and characterized among >400 EHEC O157 clinical and cattle isolates by PCR. Optical restriction maps of BBG strains consistently differed from those of CG strains only in the chromosomal insertion sites of Stx2-associated bacteriophages. Multiplex PCRs (stx1, stx2a, and stx2c as well as Stx-associated bacteriophage-chromosomal insertion site junctions) revealed four CG and three BBG that accounted for >90% of isolates. All BBG contained stx2c and Stx2c-associated bacteriophage-sbcB junctions. All CG contained stx2a and Stx2a-associated bacteriophage junctions in wrbA or argW. Presence or absence of stx2a (or another product encoded by the Stx2a-associated bacteriophage) is a parsimonious explanation for differential virulence of BBG and CG, as reflected in the distributions of these genotypes in humans and in the cattle reservoir