🔬 Phage Takes

Bacteriophage Ecology Group News, or BEG News, was published mostly quarterly as an online newsletter for a total of 26 issues, starting July 1, 1999 and continuing through December 31, 2007. As follows is a reprint of the editorial from the newsletter. Also included in issues were lists of new members to the Bacteriophage Ecology Group, an introduction to new website features, a list of upcoming meetings, phage images found on the web (remember, this was 2000, so effectively pre-Google), etc., but most of all, a listing of new phage ecology-related publications. The newsletter was modelled after T4 News, which was a printed newsletter distributed earlier in the 1990s. The newsletter's successors are the ongoing Phage.org website, phage-therapy.org, and the Bacteriophage Ecology Group Facebook page.

For some time whenever I've been asked that simple question, "What exactly is it that you do?" I've had a hard time coming up with an answer. I suppose that the simplest answer is that I am a microbiologist since I received my Ph.D. in a department of microbiology, I post-docced in a department of microbiology, and I now hold a faculty position in a department of microbiology. But this answer has never been terribly satisfying to me, and can be downright terrifying when this prompts individuals to ask questions pertaining to medical microbiology. I certainly am not a medical microbiologist (though I certainly wish I could pass for one). For a while I've answered that I am a microbial evolutionary ecologist. This is satisfying since I actually do see myself as an evolutionary ecologist and I do work with microbes. But there are four problems with this answer. The first is that it is not nearly specific enough. The second is that I don't have much formal training in evolutionary ecology. The third is, "Just what the heck is evolutionary ecology anyway?" And the fourth is that I live in a very small, conservative town located in the upper fringes of the U.S. Bible Belt. The just what the heck is evolutionary ecology is actually rather easy to answer: I am interested in how evolution has adapted organisms to their environments.

But microbial evolutionary ecologist is just something I say when I'm trying to impress (overwhelm, drive crazy, etc.) non-biologists. When speaking with biologists, one is obliged to employ a touch more precision. One solution is to pick some topic that I've recently been interested in such as the evolution of lysis timing in T-even bacteriophages (actually, I've been interested in this topic for over a decade). However, too much precision can be excluding. It's always nice to fit oneself within a group. Obviously I can call myself a phage ecologist, and thereby include all of you in my defining group, but from experience I've noted that if there is one thing a phage ecologist yearns to do, it is to command the respect of biologists, e.g., ecologists, who don't work with phages. So, for example, in terms of phages, what constitutes organismal biology, population, community, or ecosystem ecology, and which ecology am I?

Clearly there is a big world out there of organismal phage biology and just as clearly much of that world has far more of a molecular bent than an ecological one. Nevertheless, I see a number of areas of phage organismal ecology that I would equate without hesitation with phage organismal ecology, e.g., any circumstance in which a virion particle or phage-infected cell interacts chemically or physically with a component of an ecosystem in such a way that this interaction impacts on a phage growth parameter. Phage growth parameters include: (i) the duration of the phage eclipse period, (ii) the likelihood of reduction to lysogeny, (iii) the rate of progeny production once the eclipse period has ended, (iv) the timing of lysis, (v) the duration of the rise period, (vi) adsorption kinetics, (vii) phage inactivation kinetics, etc. That is, I see phage organismal ecology as being intimately entwined with the study of phage single-step growth (a.k.a., one-step growth) and survival along with all those complications on the phage life cycle introduced by such things as lysogeny, etc.

What, then, is phage population ecology? This I see as equivalent, minimally, to phage batch culture growth, either within a liquid medium or associated with a solid substrate. At the level of experimentation, what is the difference between phage organismal ecology and phage population ecology? In essence this comes down to a degree of control over phage adsorption including phage multiplicity considerations. That is, phage population ecology typically involves cultures that begin with multiplicities that are less than one while phage organismal ecology need not. In addition, the study of phage single-step growth typically involves a significant level of control over phage adsorption either during the initial addition of phages to hosts or following phage progeny release. Batch culture growth is the antithesis of such control and therefore can involve multiple rounds of phage adsorption and infection. Phage population ecology can also encompass phage growth in continuous culture so long as one does not dwell too greatly upon the doings of the bacterial hosts.

Phage community ecology considers the phage host as something more than simply a fancy nutrient or complex growth environment. Indeed, the concern of the phage community ecologist often (gasp!) has more to do with the welfare of bacteria than with their lovely little parasites, as well as that dreaded experimental complication: Coevolution! The practitioners of phage community ecology often employ such fancy set ups as phage-host chemostats. Still, other than the bias of phage community ecologists towards considerations of the bacteriophage host, much of phage growth within chemostats probably consists of brief periods of phage batch-culture-like excitement punctuating long intervals of waiting-for-those-dang-bacteria-populations-to-grow-back-to-a-decent-density boredom.

Ecosystem ecology is the consideration of the interactions between organisms as well as their interactions with their chemical and physical (abiotic) environment, e.g., nutrient movement through trophic structures. Clearly the impact of phages on the aquatic microbial loop is a fine and deservedly popular example of phage ecosystem ecology.

There is more, in my opinion, to phage ecology than just these examples. Phage systematics is highly relevant to an understanding of phage ecology and encompasses phage nucleic acid analysis as well as studies of bacteriophage comparative morphology, while phage therapy is an example of applied community ecology. Even phage behavioral ecology is not completely oxymoronic. My lack of sympathy for the plight of bacteria clearly limits my forays into community ecology and real ecosystems are much too complex for my blood. Perhaps, then, I am a bacteriophage organismal or population ecologist with a no-doubt unfortunate weakness for considerations of behavior? I wonder what my neighbors would say?