The anaerobic chamber, developed more than 40 years ago for microbiologic use, has evolved with operators’ needs and remains a significant tool for research and other applications worldwide. This article highlights the role of the anaerobic chamber in the clinical laboratory as well as current research using the chamber. The history and successful utilization of the tool are discussed.
Speers et al.1 note that the use of the anaerobic chamber has proven instrumental for anaerobic studies. “The application of new methodologies has greatly expanded the known diversity and potential of anaerobic microorganisms and processes. In particular, anaerobic techniques that permit the successful cultivation of microorganisms on solid media have opened new avenues for the study of the physiology and metabolic potential of many new microorganisms using molecular, genomic and proteomic tools.”1
The anaerobic chamber is being used in cutting-edge research on biomass, biofuels, and bioremediation, and in drug discovery and infectious disease identification. Due to advancements in research techniques, technicians in the clinical laboratory can now use the anaerobic chamber to evaluate the presence of disease agents in patient specimens, and sometimes to determine if the disease agent is susceptible to antibiotic treatment.
Figure 1 - Coy Anaerobic Chamber.
A chamber for growing anaerobes was the brainchild of the late Rolf Freter of the University of Michigan Medical School (Ann Arbor), who was studying anaerobic organisms in mouse intestines and wanted a ready supply of anaerobes. He asked a local engineer, Dick Coy, to build something that would provide him with the organisms. Thus, the Coy Anaerobic Chamber (Figure 1) (Coy Laboratory Products, Grass Lake, MI) was built and a Michigan biotechnology business was born.
Over time, the Coy Anaerobic Chamber has evolved to meet changing research needs. The first, and still most widely used, is the flexible vinyl chamber. Rigid chambers were developed later for specialized applications. Unless otherwise specified, the anaerobic atmosphere of 0–5 ppm of O2 is maintained by a hydrogen gas mix reacting with a palladium catalyst to remove excess oxygen. Key components of these anaerobic chambers are the gas, catalyst, catalyst fan box, temperature control accessories (if needed), and airlock. A wide variety of sizes, configurations, options, and accessories allow users to easily tailor the chamber; alternatively, the manufacturer can customize the system to the user’s needs.
J. Christopher Fenno, Ph.D., Associate Professor, Biologic Materials and Sciences, University of Michigan School of Dentistry, inherited that first Coy chamber when he arrived at the university in 1998. The original chamber, dating from the early 1970s, is sitting on a shelf in Dr. Fenno’s office as a piece of microbiology history.
Dr. Fenno runs a molecular biology laboratory; unlike most molecular biology laboratories, however, his has a Coy Anaerobic Chamber. The vinyl chamber with automatic cycling airlock is set up for use by two people to grow anaerobic bacteria, specifically the oral spirochete Treponema denticola, his research interest.
Referring to a chapter he wrote for Current Protocols in Microbiology (2005), Dr. Fenno describes the several standard ways of performing routine laboratory culture and handling of the T. denticola using the anaerobic chamber. They include: routine growth in liquid media, plating on semisolid media, and isolating T. denticola from clinical samples. Dr. Fenno characterizes use of the chamber as providing considerable advantages “in terms of atmospheric control and experimental scale.”2
Dr. Fenno’s work with T. denticola focuses on its role in periodontal diseases. He is studying the spirochete’s surface proteins and their outer membrane components because these are what drive the organism’s interactions with host tissue. Dr. Fenno expects his research to help explain the role of T. denticola in inducing the process of tissue destruction in periodontal disease.
Additionally, Dr. Fenno anticipates that his studies will contribute to basic knowledge of the molecular biology of pathogenic spirochetes. He believes that long-range studies of biochemical pathways and host interaction behaviors of readily cultivable Treponema strains can contribute to the understanding of microbe–host interactions in chronic infectious diseases, including those caused by organisms such as Treponema pallidum that are not yet able to be grown in culture.
While Dr. Fenno advances the understanding of microbe–host interactions in diseases, Ralph Tanner, Ph.D., Professor in the Department of Botany and Microbiology at the University of Oklahoma (Norman), focuses on anaerobes in the environment and putting those bacteria to use in industry. He calls himself an applied microbial physiologist.
Dr. Tanner’s work has focused on acetogens and methanogens. He first used the Coy Anaerobic Chamber in the 1970s when pursuing doctoral research at the University of Illinois (Urbana). The University of Illinois laboratory, headed by Dr. Ralph Wolfe, developed many of the techniques of modern anaerobic microbiology using early Coy Anaerobic Chambers. The laboratory continues to be a major user of the chambers.
Dr. Tanner’s research led to the first modern-day description of a hydrogen-using acetogen. The hydrogen-using acetogen is an organism that can take a single carbon substrate like CO2 and convert it to a C2 product, acetic acid, which is an important commodity chemical for renewable resources. Dr. Tanner has named new genera of acetogens and is working with several of them that can make ethanol, a liquid fuel, in the presence of carbon monoxide. Coskata, Inc. (Warrenville, IL) has initiated a demonstration plant producing ethanol from a synthesis gas using one of the acetogens isolated in Dr. Tanner’s laboratory.