Project description:Genome-wide gene expression analysis was performed with the cells in exponential and stationary growth phases. Through these two growth status, 89.6% of currently annotated genes were expressed. High-density oligonucleotide tiling arrays consisting of 379,528 50-mer probes spaced 30 bp apart across the whole Klebsiella pneumoniae MGH 78578 genome was used (Roche NimbleGen).
Project description:The screening of a cDNA derived expression library of Klebsiella pneumoniae MGH 78578 expressed in E.coli using a fusion construct and specific HaloTag interaction to a modified surface is shown. Thus, 1536 different clones were screened including positive (ompA, mdh) and negative (pyrC, gapA) reference proteins. The goal of the screening was to identify potential novel immunogenic proteins from K. pneumoniae by selecting clones showing a high signal intensity in comparison to the known antigens used as positve markers. Afterwards, the most promising clones were sequenced to identify the gene and corresponding protein and these proteins were then investigated further. Consequently, 14 novel immunogenic proteins could be identified. In total 1536 (4 x 384) different lysates were spotted on different microarray slides. Each slides contained 3600 distinct spots, seperated into two compartments of 1800 spots each. Each compartment comprised quadruplicate replicates of each sample lysate with controls being analysed with more replicates. As controls we used: ompA1, ompA2 and mdh (3 x 40 replicates) as positive reference proteins, as they have been described as immunogenic before. gapA and pyrC (2 x 40 replicates) as negative reference proteins, additionally two sets of E.coli cell lysates without fusionprotein expressed, namely Acella electrocompetent cells (40 replicates) and KRX (32 replicates). Last but not least a buffer control (24 replicates) was included. Therefore, each set of replicate slides contained 376 different samples and 8 controls. Each screening was performed with three replicate slides. Consequently, a total number of 12 slides were screened (4 sets of samples x 3 replicates). For identification rabbit polyclonal antibody to K. pneumoniae (Acris AP00792PU-N) as primary and Goat polyclonal to Rabbit IgG conjugated with ChromeoTM-546 (Abcam ab60317) as secondary antibody were used. The top compartment was incubated first with primary antibody, while the bottom compartment was incubated with PBS at the same time. Afterwards both compartments were incubated with secondary antibody.