Dr. Hiroshi Nikaido is a distinguished molecular biologist whose pioneering research has fundamentally transformed our understanding of bacterial membrane structures and functions. He serves as Professor of the Graduate School in the Division of Biochemistry, Biophysics and Structural Biology at the University of California, Berkeley, where he has conducted groundbreaking research for decades. After earning both his M.D. (1955) and doctorate in medical science from Keio University School of Medicine in Tokyo, Japan, he established himself as a leading authority in microbial membrane biochemistry. His career has been characterized by an unwavering focus on the molecular architecture of bacterial envelopes, particularly in gram-negative species, making him one of the most influential figures in modern microbiology.
Dr. Nikaido pioneered the characterization of the outer membrane of gram-negative bacteria as a critical permeability barrier to antibiotics and toxic agents, demonstrating its asymmetric lipid bilayer structure that significantly impedes the passage of lipophilic compounds. His groundbreaking discovery and characterization of porin channels revealed the molecular mechanisms by which small nutrient molecules cross the outer membrane rapidly, fundamentally transforming our understanding of bacterial permeability. He further elucidated the mechanism of multidrug efflux pumps with unusually broad specificity, demonstrating how these active transport systems work synergistically with the passive permeability barrier to prevent antibiotic entry into bacterial cells. His 2003 Science paper on the structural basis of multiple drug-binding capacity of the AcrB multidrug efflux pump became a landmark publication that continues to guide research in antibiotic resistance mechanisms.
As a member of both the National Academy of Sciences (elected 2009) and the American Academy of Arts and Sciences (elected 2005), Dr. Nikaido has profoundly shaped the field of bacterial membrane research through his rigorous scientific approach and methodical investigations. His extensive publication record, spanning over 250 influential papers, has established the conceptual framework that guides contemporary research on antibiotic resistance mechanisms and continues to inform new generations of microbiologists. Though now in emeritus status, his conceptual frameworks remain essential for understanding intrinsic antibiotic resistance in gram-negative pathogens and developing novel antimicrobial strategies. Dr. Nikaido's legacy endures through the ongoing application of his discoveries in addressing one of modern medicine's most pressing challenges: combating antibiotic-resistant infections worldwide.
