Feldman, E. A., S. Ni, I. D. Sahu, C. H. MIshler, J. D. Levengood, Y. Kushnir, R. M. McCarrick, G. A. Lorigan, B. S. Tolbert, S. M. Callahan and M. A. Kennedy (2012) Differential binding properties between PatS C-terminal peptide fragments of HetR from Anabaena sp. PCC 7120. Biochemistry 51:2436-2442.
Huang, Y., Callahan, S. M. and Hadfield, M. G. (2012) Recruitment in the sea: bacterial genes required for inducing larval settlement in a polychaete worm. Sci. Rep. DOI: 10.1038/srep00228.
Higa, K. C., Rajagopalan, R., Risser, D. D., Rivers, O. S., Tom, S. K., Videau, P. and Callahan, S. M. (2012) The RGSGR amino acid motif of the intercellular signaling protein, HetN, is required for patterning of heterocysts in Anabaena sp. strain PCC 7120. Mol. Microbiol. 83:682-693.
Tom, S. K. and S. M. Callahan. (2012) The putative phosphatase all1758 is necessary for normal growth, cell size, and synthesis of the minor heterocyst-specific glycolipid in the cyanobacterium Anabaena sp. strain PCC 7120. Microbiology. 158:380-389.
Kim, Y., Joachimiak, G., Zi, Y., Binkowski, T. A., Zhang, R., Gornicki, P., Callahan, S. M., Hess, W. R., Haselkorn, R. & Joachimiak, A. (2011) Structure of the transcription factor HetR required for heterocyst differentiation in cyanobacteria. Proc. Natl. Acad. Sci. 108: 10109-10114.
Feldman, E. A., Ni, S., Sahu, I. D., Mishler, C. H., Risser, D. D., Murakami, J. L., Tom, S. K., McCarrick, R. M., Lorigan, G. A., Tolbert, B. S., Callahan, S. M. & Kennedy, M. A. (2011) Evidence for direct binding between HetR from Anabaena sp. PCC 7120 and PatS-5. Biochemistry 50: 9212-9224.
Higa, K. C. & Callahan, S. M. (2010) Ectopic expression of hetP can partially bypass the need for hetR in heterocyst differentiation by Anabaena sp. strain PCC 7120. Mol. Microbiol. 77: 562-574.
Young-Robbins, S. S., D. D. Risser, J. Moran, R. Haselkorn and S. M. Callahan. (2010) Transcriptional regulation of the heterocyst patterning gene patA from Anabaena sp. strain PCC 7120. J. Bacteriol. 192:4732-4740
Zhu, M., S. M. Callahan and J. A. Allen. (2010) Maintenance of heterocyst patterning in a filamentous cyanobacterium. J. Biol. Dyn. 4:621-633.
Rajagopalan, R. and S. M. Callahan. (2010) Temporal and spatial regulation of the four transcription start sites of hetR from Anabaena sp. strain PCC 7120. J. Bacteriol. 192:1088-1096
Risser, D. D. and S. M. Callahan. (2009) Genetic and cytological evidence that heterocyst patterning is regulated by inhibitor gradients that promote activator decay. Proc. Nat. Acad. Sci., USA 106:19884-19888.
Risser, D. D. and S. M. Callahan. (2008) HetF and PatA control levels of HetR in Anabaena sp. strain PCC 7120. J. Bacteriol. 190:7645-7654.
Qin, N., Callahan, S. M., Dunlap, P. V., and A. M. Stevens. (2007) Analysis of LuxR Regulon Gene Expression during Quorum Sensing in Vibrio fischeri MJ-100. J. Bacteriol. 189:4127-4134.
Risser, D. D. and S. M. Callahan. (2007) Mutagenesis of hetR reveals amino acids necessary for HetR function. J. Bacteriol. 189:2460-2467
Nayar A. S., H. Yamaura, R. Rajagopalan, D. D. Risser and S. M. Callahan. (2007) FraG is necessary for filament integrity and heterocyst maturation in the cyanobacterium Anabaena sp. strain PCC 7120. Microbiology. 153: 601-607.
Orozco, C. C., Risser, D. D., and S. M. Callahan. (2006) Epistasis analysis of four genes from Anabaena sp. Strain PCC 7120 suggests a connection between PatA and PatS in heterocyst pattern formation. J. Bacteriol. 188:1808-1816.
Borthakur, P. B., Orozco, C. C., Young-Robbins, S. S., Haselkorn, R., and S. M. Callahan. (2005) Inactivation of patS and hetN causes lethal levels of heterocyst differentiation in the filamentous cyanobacterium Anabaena sp. PCC 7120. Mol. Microbiol. 57:111-123.
Callahan, S. M. and W. J. Buikema (2001) The role of HetN in maintenance of the heterocyst pattern in Anabaena sp. PCC 7120. Mol. Microbiol. 40:941-950.