David B. Dusenbery
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David B. Dusenbery is a biophysicist with a central interest in how
information Information is an abstract concept that refers to that which has the power to inform. At the most fundamental level information pertains to the interpretation of that which may be sensed. Any natural process that is not completely random ...
influences the behavior of
organism In biology, an organism () is any living system that functions as an individual entity. All organisms are composed of cells (cell theory). Organisms are classified by taxonomy into groups such as multicellular animals, plants, and ...
s. In later years, he also considered the physical constraints hydrodynamics imposes on
microorganism A microorganism, or microbe,, ''mikros'', "small") and ''organism'' from the el, ὀργανισμός, ''organismós'', "organism"). It is usually written as a single word but is sometimes hyphenated (''micro-organism''), especially in olde ...
s and
gametes A gamete (; , ultimately ) is a haploid cell that fuses with another haploid cell during fertilization in organisms that reproduce sexually. Gametes are an organism's reproductive cells, also referred to as sex cells. In species that produce ...
.


Academic positions

He received his
Bachelor of Arts Bachelor of arts (BA or AB; from the Latin ', ', or ') is a bachelor's degree awarded for an undergraduate program in the arts, or, in some cases, other disciplines. A Bachelor of Arts degree course is generally completed in three or four year ...
in Physics from
Reed College Reed College is a private liberal arts college in Portland, Oregon. Founded in 1908, Reed is a residential college with a campus in the Eastmoreland neighborhood, with Tudor-Gothic style architecture, and a forested canyon nature preserve at ...
in 1964 and his PhD in Biophysics from the
University of Chicago The University of Chicago (UChicago, Chicago, U of C, or UChi) is a private university, private research university in Chicago, Illinois. Its main campus is located in Chicago's Hyde Park, Chicago, Hyde Park neighborhood. The University of Chic ...
in 1970. Dusenbery was a postdoc at the
California Institute of Technology The California Institute of Technology (branded as Caltech or CIT)The university itself only spells its short form as "Caltech"; the institution considers other spellings such a"Cal Tech" and "CalTech" incorrect. The institute is also occasional ...
1970–1973. He was on the faculty of the Georgia Institute of Technology from 1973 to 2002 in Biology, with a joint appointment in Physics to 1978.


Research

Most of Dusenbery's research deals with how
information Information is an abstract concept that refers to that which has the power to inform. At the most fundamental level information pertains to the interpretation of that which may be sensed. Any natural process that is not completely random ...
controls behavior. At Caltech and the early years at Georgia Tech, Dusenbery focused on experimental studies of the nematode '' Caenorhabditis elegans'' because of its small nervous system and favorable genetics. These experimental studies inspired the development of several innovative techniques: * Countercurrent separation for isolating mutant individuals altered in their tendency to swim toward a chemical. * A method for applying controlled stimulation to an individual nematode and recording its responses. * A method using computer analysis of live video to simultaneously track many individuals and record changes in their locomotion. * The video tracking method was even used as a detector of sensory stimuli emanating from a gas chromatograph. * Dusenbery had several students who developed a variety of techniques employing nematodes for inexpensive testing of samples (industrial or environmental) for several kinds of toxicity. Initially, Dusenbery was attempting to understand the flow of information in the nervous system of this simple animal. Later, he turned to the flow of information outside the organism, and how physics constrains how organisms behave. More recently, he has also considered hydrodynamic constraints on small organisms, which can only swim at low speeds, where viscosity is far more important than inertia (low Reynolds numbers). From physical analysis, Dusenbery predicted that the long-held belief that bacteria were too small to employ spatial sensing mechanisms to follow chemical gradients was erroneous and predicted that bacteria following steep gradients of chemicals at high concentrations would benefit from using a spatial mechanism. In 2003, a new bacterial species was discovered that swim sideways and respond to differences in oxygen concentration at the two ends of the cell, allowing them to follow steep gradients of oxygen. Similar considerations have also been applied to the behaviors of
gamete A gamete (; , ultimately ) is a haploid cell that fuses with another haploid cell during fertilization in organisms that reproduce sexually. Gametes are an organism's reproductive cells, also referred to as sex cells. In species that produce ...
s, leading to an explanation of why the sperm/egg ( ovum) and thus the
male Male (symbol: ♂) is the sex of an organism that produces the gamete (sex cell) known as sperm, which fuses with the larger female gamete, or ovum, in the process of fertilization. A male organism cannot reproduce sexually without access to ...
/
female Female ( symbol: ♀) is the sex of an organism that produces the large non-motile ova (egg cells), the type of gamete (sex cell) that fuses with the male gamete during sexual reproduction. A female has larger gametes than a male. Females ...
distinctions exist.Dusenbery, D.B. (2006). Selection for high gamete encounter rates explains the evolution of anisogamy using plausible assumptions about size relationships of swimming speed and duration. J. Theoretical Biol. 241:33-8.


References


Notable publications


Books

* Dusenbery, David B. (1992). ''Sensory Ecology: How Organisms Acquire and Respond to Information''. W.H. Freeman, New York. . * Dusenbery, David B. (1996). “Life at Small Scale: The Behavior of Microbes”. Scientific American Library. . * Dusenbery, David B. (2009). “Living at Micro Scale: The Unexpected Physics of Being Small”. Harvard University Press. .


Research papers

*Dusenbery, D.B. (1996). Information is where you find it. Biol. Bull. 191:124-128. *Dusenbery, D.B. (1997). Minimum size limit for useful locomotion by free-swimming microbes. Proc. Natl. Acad. Sci. USA 94:10949-10954. *Dusenbery, D.B. (1998). Fitness landscapes for effects of shape on chemotaxis and other behaviors of bacteria. J. Bacteriol. 180 (22):5978-5983. *Dusenbery, D.B. (2000). Selection for high gamete encounter rates explains the success of male and female mating types. J. Theoret. Biol. 202:1-10. *Dusenbery, D.B. (2002). Ecological Models Explaining the Success of Distinctive Sperm and Eggs (Oogamy). J. Theoretical Biol. 219:1-7. *Dusenbery, D.B. (2006). Selection for high gamete encounter rates explains the evolution of anisogamy using plausible assumptions about size relationships of swimming speed and duration. J. Theoretical Biol. 241:33-8.


External links


A more complete list of David Dusenbery’s research papers.David Dusenbery’s website
{{DEFAULTSORT:Dusenbery, David B. American biophysicists Reed College alumni University of Chicago alumni Georgia Tech faculty Living people Year of birth missing (living people)