of polysaccharides and a prevalence of proteases and amino acid degradation and transport pathways, indicating that their preferred diet consists of proteins and their breakdown products. An isolate of a bacterium found to produce PHBs was identified as B. cereus through analysis of 16S rRNA sequences as well as similarity of morphological and biochemical characteristics. PHBs may be produced when there is excess carbon or limited essential nutrients present in the environment, and they are later broken down by the microbe as a fuel source under starvation conditions. This indicates the potential role of B. cereus in producing biodegradable plastic substitutes. PHB production was highest when provided with glucose as a carbon source. Genomics The genome of B. cereus has been characterized and shown to contain over 5 million bp of DNA. Out of these, more than 5500 protein-encoding genes have been identified, of which the top categories of genes with known functions include: metabolic processes, processing of proteins, virulence factors, response to stress, and defense mechanisms. Many of the genes categorized as virulence factors, stress responses, and defense mechanisms encode factors in antibiotic resistance. There are approximately 600 genes which are common in 99% of the taxa of B. cereus sensu lato, which constitutes around 1% of all genes in the pan-genome. Due to the prevalence of horizontal gene transfer among bacteria, the pan-genome of B. cereus is continually expanding. The GC content of its DNA across all strains is approximately 35%. Following exposure to non-lethal acid shock at pH 5.4-5.5, the arginine deiminase gene in B. cereus, arcA, shows substantial up-regulation. This gene is part of the arcABC operon which is induced by low-pH environments in Listeria monocytogenes, and is associated with growth and survival in acidic environments. This suggests that this gene is also important for survival of B. cereus in acidic environments. The activation of virulence factors has been shown to be transcriptionally regulated via quorum-sensing in B. cereus. The activation of many virulence factors secreted is dependent on the activity of the Phospholipase C regulator (PlcR), a transcriptional regulator which is most active at the beginning of the stationary phase of growth. A small peptide called PapR acts as the effector in the quorum-sensing pathway, and when reimported into the cell, it interacts with PlcR to activate transcription of these virulence genes. When point mutations were introduced into the plcR gene using the CRISPR/Cas9 system,