The Cryptococcus neoformans Rim101 Transcription Factor Directly Regulates Genes Required for Adaptation to the Host

The Rim101 protein is a conserved pH-responsive transcription factor that mediates important interactions between several fungal pathogens and the infected host. In the human fungal pathogen Cryptococcus neoformans, the Rim101 protein retains conserved functions to allow the microorganism to respond to changes in pH and other host stresses. This coordinated cellular response enables this fungus to effectively evade the host immune response. Preliminary studies suggest that this conserved transcription factor is uniquely regulated in C. neoformans both by the canonical pH-sensing pathway and by the cyclic AMP (cAMP)/protein kinase A (PKA) pathway. Here we present comparative transcriptional data that demonstrate a strong concordance between the downstream effectors of PKA and Rim101. To define Rim101-dependent gene expression during a murine lung infection, we used nanoString profiling of lung tissue infected with a wild-type or rim101Δ mutant strain. In this setting, we demonstrated that Rim101 controls the expression of multiple cell wall-biosynthetic genes, likely explaining the enhanced immunogenicity of the rim101Δ mutant. Despite its divergent upstream regulation, the C. neoformans Rim101 protein recognizes a conserved DNA binding motif. Using these data, we identified direct targets of this transcription factor, including genes involved in cell wall regulation. Therefore, the Rim101 protein directly controls cell wall changes required for the adaptation of C. neoformans to its host environment. Moreover, we propose that integration of the cAMP/PKA and pH-sensing pathways allows C. neoformans to respond to a broad range of host-specific signals

Pre-treatment of Malaysian agricultural wastes toward biofuel production

Various renewable energy technologies are under considerable interest due to the projected depletion of our primary sources of energy and global warming associated with their utilizations. One of the alternatives under focus is renewable fuels produced from agricultural wastes. Malaysia, being one of the largest producers of palm oil, generates abundant agricultural wastes such as fibers, shells, fronds, and trunks with the potential to be converted to biofuels. However, prior to conversion of these materials to useful products, pre-treatment of biomass is essential as it influences the energy utilization in the conversion process and feedstock quality. This chapter focuses on pre-treatment technology of palm-based agriculture waste prior to conversion to solid, liquid, and gas fuel. Pre-treatment methods can be classified into physical, thermal, biological, and chemicals or any combination of these methods. Selecting the most suitable pre-treatment method could be very challenging due to complexities of biomass properties. Physical treatment involves grinding and sieving of biomass into various particle sizes whereas thermal treatment consists of pyrolysis and torrefaction processes. Additionally biological and chemical treatment using enzymes and chemicals to derive lignin from biomass are also discussed