Bacteria are the main nutritional competitors of saprophytic fungi during colonization of their ecological niches. This competition involves the mutual secretion of antimicrobials that kill or inhibit the growth of the competitor. Over the last years it has been demonstrated that fungi respond to the presence of bacteria with changes of their transcriptome, but the significance of these changes with respect to competition for nutrients is not clear as functional proof of the antibacterial activity of the induced gene products is often lacking. Here, we report the genome-wide transcriptional response of the coprophilous mushroom Coprinopsis cinerea to the bacteria Bacillus subtilis and Escherichia coli. The genes induced upon co-cultivation with each bacterium were highly overlapping, suggesting that the fungus uses a similar arsenal of effectors against Gram-positive and -negative bacteria. Intriguingly, the induced genes appeare to encode predominantly secreted peptides and proteins with predicted antibacterial activities, which was validated by comparative proteomics of the C. cinerea secretome. Induced members of two putative antibacterial peptide and protein families in C. cinerea, the cysteine-stabilized αβ-defensins (Csαβ-defensins) and the GH24-type lysozymes, were purified, and their antibacterial activity was confirmed. These results provide compelling evidence that fungi are able to recognize the presence of bacteria and respond with the expression of an arsenal of secreted antibacterial peptides and proteins.
Different mechanisms mediate the toxicity of RNA. Genomic retroviral mRNA hijacks infected host cell factors to enable virus replication. The viral genomic RNA of the human immunodeficiency virus (HIV) encompasses nine genes encoding in less than 10 kb all proteins needed for replication in susceptible host cells. To do so, the genomic RNA undergoes complex alternative splicing to facilitate the synthesis of the structural, accessory, and regulatory proteins. However, HIV strongly relies on the host cell machinery recruiting cellular factors to complete its replication cycle. Antiretroviral therapy (ART) targets different steps in the cycle, preventing disease progression to the acquired immunodeficiency syndrome (AIDS). The comprehension of the host immune system interaction with the virus has fostered the development of a variety of vaccine platforms. Despite encouraging provisional results in vaccine trials, no effective vaccine has been developed, yet. However, novel promising vaccine platforms are currently under investigation.
25 August 2013 in Cellular and Molecular Neurobiology
Gamma-Retroviral (RVVs) and lentiviral vectors (LVVs) represent indispensable tools in somatic gene therapy, mediating the efficient, stable transfer of therapeutic genes into a variety of human target cells. LVVs, in contrast to RVVs, are capable of stably genetically modifying non-proliferating target cells, making them the superior instrument in cell and gene therapy. To date, the LVV manufacturing process employs human embryonic kidney cells (HEK293) and derivatives thereof transiently transfected with multiple plasmids encoding the required viral vector components. Alternatively, stable packaging cell lines were developed and engineered to express all vector components in trans. Currently, these cells are mostly cultured in cell stacks, where they grow adherently in 2D layers, limiting the scale-up of vector production. The production of viral vectors using stable suspension cell lines enables larger-scale production and higher yields under controlled conditions. Here, we review the improvements made to enhance vector safety and production yield. Current advancements in the establishment of stable packaging cell lines enabling inducible and constitutive LVV production are summarized and discussed. Manufacturing processes for lentiviral vectors using bioreactors with perfusion systems are required to meet the growing demand in cell and gene therapy and to reduce production and therapy costs.