大森 正之（おおもり まさゆき、1943年1月 -）は、日本の生物学研究者。東京大学名誉教授、元埼玉大学教授。シアノバクテリア（藍藻）を用いた環境応答現象の解析による、砂漠緑化などの地球環境維持への応用を研究を行っている。理学博士（東京大学、1973年）。

専門分野 
分子生物学
分子・細胞生理

略歴 
1961年3月　東京都立日比谷高等学校卒業 
1966年3月　埼玉大学文理学部理学科卒業
1968年3月　東京大学大学院理学系研究科修士課程修了
1968年　東京大学海洋研究所助手
1973年　理学博士（東京大学）を授与される
1988年11月　東京大学海洋研究所助教授
1992年4月　東京大学教養学部教授
1994年4月　東京大学大学院総合文化研究科教授（広域科学専攻　生命環境科学系　環境応答論講座）
2004年3月　東京大学退職
2004年4月　埼玉大学理学部分子生物学科教授
2004年6月　東京大学名誉教授
2006年4月　埼玉大学大学院教授（理工学研究科）（配置換え）
2008年4月　中央大学教授（理工学部）
2013年3月　中央大学教授（理工学部）退任

論文 
Katayama M, Wada Y, Ohmori M.  "Molecular cloning of the cyanobacterial adenylate cyclase gene from the filamentous cyanobacterium Anabaena cylindrica." ,  J. Bacteriol., 1995, 177(13):3873-8.
Yashiro K, Sakamoto T, Ohmori M. "Molecular characterization of an adenylate cyclase gene of the cyanobacterium Spirulina platensis." , Plant. Mol. Biol., 1996, 31:175-181.
Katayama M, Ohmori M. "Isolation and characterization of multiple adenylate cyclase genes from the cyanobacterium Anabaena sp. strain PCC 7120." , J. Bacteriol., 1997, 179(11):3588-93.
Kasahara M, Yashiro K, Sakamoto T, Ohmori M. "The Spirulina platensis adenylate cyclase gene, cyaC, encodes a novel signal transduction protein." , Plant. Cell. Physiol., 1997, 38(7):828-36.
Terauchi K, Ohmori M. "An adenylate cyclase, Cya1, regulates cell motility in the cyanobacterium Synechocystis sp. PCC 6803." , Plant. Cell. Physiol., 1999, 40(2):248-51.
Kasahara M, Ohmori M. "Activation of a cyanobacterial adenylate cyclase, CyaC, by autophosphorylation and a subsequent phosphotransfer reaction." , J. Biol. Chem., 1999, 274(21):15167-72.
Okamoto S, Ikeuchi M, Ohmori M. "Experimental analysis of recently transposed insertion sequences in the cyanobacterium Synechocystis sp. PCC 6803." , DNA. Res., 1999, 6(5):265-73.
Yoshimura H, Hisabori T, Yanagisawa S, Ohmori M. "Identification and characterization of a novel cAMP receptor protein in the cyanobacterium Synechocystis sp. PCC 6803." , J. Biol. Chem., 2000, 275(9):6241-5.
Kasahara M, Unno T, Yashiro K, Ohmori M. "CyaG, a novel cyanobacterial adenylyl cyclase and a possible ancestor of mammalian guanylyl cyclases." , J. Biol. Chem., 2001, 276(13):10564-9.
Yoshihara S, Geng X, Okamoto S, Yura K, Murata T, Go M, Ohmori M, Ikeuchi M. "Mutational analysis of genes involved in pilus structure, motility and transformation competency in the unicellular motile cyanobacterium Synechocystis sp. PCC 6803." , Plant. Cell. Physiol., 2001, 42(1):63-73.
Ohmori M, Ikeuchi M. "Post-genome project of cyanobacteria." , Tanpakushitu. Kakusan. Koso., 2001, 46:2486-92.
Ohmori M, Ikeuchi M, Sato N, Wolk P, Kaneko T, Ogawa T, Kanehisa M, Goto S, Kawashima S, Okamoto S, Yoshimura H, Katoh H, Fujisawa T, Ehira S, Kamei A, Yoshihara S, Narikawa R, Tabat S. "Characterization of genes encoding multi-domain proteins in the genome of the filamentous nitrogen-fixing Cyanobacterium Anabaena sp. strain PCC 7120." , DNA. Res., 2001, 8(6):271-84.
Tada T, Sekimoto H, Ohmori M. "Biochemical characterization of an adenylate cyclase, CyaB1, in the cyanobacterium anabaena sp. strain PCC 7120." , J. Plant. Res., 2001, 114:387-394.
Nishimura R, Hayashi M, Wu GJ, Kouchi H, Imaizumi-Anraku H, Murakami Y, Kawasaki S, Akao S, Ohmori M, Nagasawa M, Harada K, Kawaguchi M. "HAR1 mediates systemic regulation of symbiotic organ development." , Nature., 2002, 420:426-429.
Nishimura R, Ohmori M, Fujita H, Kawaguchi M. "A Lotus basic leucine zipper protein with a RING-finger motif negatively regulates the developmental program of nodulation." , Proc. Natl. Sci. USA , 2002, 99:15206-15210.
Nishimura R, Ohmori M, Kawaguchi M. "The novel symbiotic phenoltype of enhanced-nodulation mutant of Lotus japonicus : astray mutant is an early nodulating mutant with wider nodulation zone." , Plant. Cell. Physiol., 2002, 43:853-859.
Yoshimura H, Yoshihara S, Okamoto S, Ikeuchi M, Ohmori M. "A cAMP receptor protein, SYCRP1, is responsible for the cell motility of Synechocystis sp. PCC 6803." , Plant. Cell. Physiol., 2002, 43(4):460-3.
Ohmori M, Terauchi K, Okamoto S, Watanabe M. "Regulation of cAMP-mediated photosignaling by a phytochrome in the cyanobacterium Anabaena cylindrica." , Photochem. Photobiol., 2002, 75(6):675-9.
Yoshimura H, Yanagisawa S, Kanehisa M, Ohmori M. "Screening for the target gene of cyanobacterial cAMP receptor protein SYCRP1." , Mol. Microbiol., 2002, 43(4):843-53.
Okamoto S, Ohmori M. "The cyanobacterial PilT protein responsible for cell motility and transformation hydrolyzes ATP." , Plant. Cell. Physiol., 2002, 43(10):1127-36.
Ehira S, Ohmori M, Sato N. "Genome-wide expression analysis of the responses to nitrogen deprivation in the heterocyst-forming cyanobacterium Anabaena sp. strain PCC 7120." , DNA. Res., 2003, 10(3):97-113.
Ehira S, Hamano T, Hayashida T, Kojima K, Nakamoto H, Hiyama T, Ohmori M, Shivaji S, Sato N. "Conserved temperature-dependent expression of RNA-binding proteins in cyanobacteria with different temperature optima." , FEMS. Microbiol. Lett., 2003, 225(1):137-42.
Tada T, Ohmori M, Iida H. "Molecular dissection of the hydrophobic segments H3 and H4 of the yeast Ca2+ channel component Mid1." , J. Biol. Chem., 2003, 278:9647-9654.
Katoh H, Shiga S, Nakahira Y, Ohmori M. "Isolation and characterization of drought-tolerant cyanobacterium Nostoc sp. HK-01." , Microb. Environ., 2003, 18:82-88.
Katoh H, Asthana RK, Ohmori M. "Gene expression in the cyanobacterium Anabaena sp. PCC 7120 under desiccation." , Microb. Ecol.,  2004, 47(2):164-74. Epub., 2004, Feb., 02.
Terauchi K, Ohmori M. "Blue light stimulates cyanobacterial motility via a cAMP signal transduction system." , Mol. Microbiol., 2004, 52(1):303-9.
Sato N, Ohmori M, Ikeuchi M, Tashiro K, Wolk CP, Kaneko T, Okada K, Tsuzuki M, Ehira S, Katoh H, Okamoto S, Yoshimura H, Fujisawa T, Kamei A, Yoshihara S, Narikawa R, Hamano T, Tabata S, Kuhara S. "Use of segment-based microarray in the analysis of global gene expression in response to various environmental stresses in the cyanobacterium Anabaena sp. PCC 7120." , J. Gen. Appl. Microbiol., 2004, 50(1):1-8.
Omagari K, Yoshimura H, Takano M, Hao D, Ohmori M, Sarai A, Suyama A. "Systematic single base-pair substitution analysis of DNA binding by the cAMP receptor protein in cyanobacterium Synechocystis sp. PCC 6803." , FEBS. Lett., 2004, 9;563(1-3):55-8.
Narikawa R, Okamoto S, Ikeuchi M, Ohmori M. "Molecular evolution of PAS domain-containing proteins of filamentous cyanobacteria through domain shuffling and domain duplication." , DNA. Res., 2004, 30;11(2):69-81.
Ohmori M, Okamoto S. "Photoresponsive cAMP signal transduction in cyanobacteria." , Photochem. Photobiol. Sci., 2004, 3(6):503-11.
Suzuki T, Yoshimura H, Hisabori T, Ohmori M. "Two cAMP receptor proteins with different biochemical properties in the filamentous cyanobacterium Anabaena sp. PCC 7120." , FEBS. Lett., 2004, 30;571(1-3):154-60.
Okamoto S, Kasahara M, Kamiya A, Nakahira Y, Ohmori M. "A phytochrome-like protein AphC triggers the cAMP signaling induced by Far-red light in the cyanobacterium Anabaena sp. strain PCC 7120." , Photochem. Photobiol., 2004, 80(3):429-33.
Tada T, Ohmori M, Iida H. "Phe356 in the yeast Ca2+ channel component Mid1 is a key residue for viability after exposure to alpha-factor." , Biochem. Biophys. Res. Commun., 2004, 313:752-757.
Ehira S, Ohmori M, Sato N. "Identification of low-temperature regulated ORFs in the cyanobacterium Anabaena sp. strain PCC 7120 : distinguishing the effects of low temperature from the effects of photosystem Ⅱ excitation pressure." , Plant. Cell. Physiol., 2005, in press.
Hosoya-Matsuda N, Motohashi K, Yoshimura H, Nozaki A, Inoue K, Ohmori M, Hisabori T. "Anti-oxidative stress system in cyanobacteria. Significance of type Ⅱ peroxiredoxin and the role of 1-Cys peroxiredoxin in Synechocystis sp. strain PCC 6803." , J. Biol. Chem., 2005, 7;280(1):840-846.
Fujisawa T, Ohmori M. "Biochemical properties of a cAMP phosphodiesterase in the cyanobacterium Anabaena sp. strain PCC 7120." , Microbes. Environ., 2005, 20:92-96.