The Transcriptional Response of Drosophila melanogaster to Infection with the Sigma Virus (Rhabdoviridae)

Bacterial and fungal infections induce a potent immune response in Drosophila melanogaster, but it is unclear whether viral infections induce an antiviral immune response. Using microarrays, we examined the changes in gene expression in Drosophila that occur in response to infection with the sigma virus, a negative-stranded RNA virus (Rhabdoviridae) that occurs in wild populations of D. melanogaster. We detected many changes in gene expression in infected flies, but found no evidence for the activation of the Toll, IMD or Jak-STAT pathways, which control immune responses against bacteria and fungi. We identified a number of functional categories of genes, including serine proteases, ribosomal proteins and chorion proteins that were overrepresented among the differentially expressed genes. We also found that the sigma virus alters the expression of many more genes in males than in females. These data suggest that either Drosophila do not mount an immune response against the sigma virus, or that the immune response is not controlled by known immune pathways. If the latter is true, the genes that we identified as differentially expressed after infection are promising candidates for controlling the host's response to the sigma virus

RNAi-Based Functional Genomics Identifies New Virulence Determinants in Mucormycosis

Mucorales are an emerging group of human pathogens that are responsible for the lethal disease mucormycosis. Unfortunately, functional studies on the genetic factors behind the virulence of these organisms are hampered by their limited genetic tractability, since they are reluctant to classical genetic tools like transposable elements or gene mapping. Here, we describe an RNAi-based functional genomic platform that allows the identification of new virulence factors through a forward genetic approach firstly described in Mucorales. This platform contains a whole-genome collection of Mucor circinelloides silenced transformants that presented a broad assortment of phenotypes related to the main physiological processes in fungi, including virulence, hyphae morphology, mycelial and yeast growth, carotenogenesis and asexual sporulation. Selection of transformants with reduced virulence allowed the identification of mcplD, which encodes a Phospholipase D, and mcmyo5, encoding a probably essential cargo transporter of the Myosin V family, as required for a fully virulent phenotype of M. circinelloides. Knock-out mutants for those genes showed reduced virulence in both Galleria mellonella and Mus musculus models, probably due to a delayed germination and polarized growth within macrophages. This study provides a robust approach to study virulence in Mucorales and as a proof of concept identified new virulence determinants in M. circinelloides that could represent promising targets for future antifungal therapies

Feeding difficulties in neonates following cardiac surgery: Determinants of prolonged feeding-tube use

Aim The aims of this study were to examine the prevalence and potential correlates of feeding difficulties in infants who underwent cardiac surgery in the neonatal period and to investigate resource utilisation by infants with feeding difficulties. Methods All neonates who underwent their first cardiac surgery at the Heart Centre for Children, The Children's Hospital at Westmead, between January and December, 2009 were included. Demographic, preoperative, intraoperative, and postoperative data were collected via electronic medical records. For the purpose of this study, feeding difficulty was defined as the requirement for ongoing tube feeding at the time of discharge home or transfer to another hospital. Results Out of a total of 79 neonates, 24 (30%) were discharged home or transferred to another hospital with a feeding tube. Feeding difficulties were associated with the presence of a genetic syndrome (p<0.0001), assisted feeding preoperatively (odds ratio (OR)=4.4, p=0.03), and having a palliative procedure before biventricular repair (OR=5.1, p=0.02). Infants with feeding difficulties had significantly more reviews by speech pathologists (M=5.9, SD=7.9), dieticians (M=5.9, SD=5.4), and cardiac clinical nurse consultants (M=1.2, SD=1.4) compared with those without feeding difficulties. Conclusions This study identified factors that can be used in the early recognition of infant feeding difficulties, to help guide the direction of limited health resources, as well as being focal points for future research and clinical practice improvement