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Part 2: The Abstract

As with the Title, potential Reviewers will have access to your Abstract before deciding whether to review your paper. The more interesting and impactful your abstract appears, the more likely it will be that an influential scientist will agree to review your manuscript. Thus, your goal is to generate an intriguing synopsis of your work that is clear and emphasizes the profoundness of your work. Furthermore, a well-written abstract will entice scientists in your field to read on, paving the way for future citations. So how does one generate the most inviting abstract? There are several ways to writing such an abstract. Below, I describe, through an example, a simple yet very effective method.

Example Abstract

Respiratory complex I (NADH:ubiquinone oxidoreductase) is a large mitochondrial inner membrane enzyme consisting of 45 subunits and 8 iron-sulfur (Fe/S) clusters. While complex I dysfunction is the most common reason for mitochondrial diseases, the assembly of complex I and its Fe/S cofactors remains elusive. Here, we identify the human mitochondrial P-loop NTPase, designated huInd1, that is critically required for the assembly of complex I. huInd1 can bind an Fe/S cluster via a conserved CXXC motif in a labile fashion. Knockdown of huInd1 in HeLa cells by RNA interference technology led to strong decreases in complex I protein and activity levels, remodeling of respiratory supercomplexes, and alteration of mitochondrial morphology. In addition, huInd1 depletion resulted in massive decreases in several subunits (NDUFS1, NDUFV1, NDUFS3, and NDUFA13) of the peripheral arm of complex I, with the concomitant appearance of a 450-kDa subcomplex representing part of the membrane arm. By a novel radiolabeling technique, the amount of iron associated with complex I was also shown to reflect the dependence of this enzyme on huInd1 for assembly. Together, these data identify huInd1 as a new assembly factor for human respiratory complex I with a possible role in the delivery of one or more Fe/S clusters to complex I subunits. (Sheftel et al., MCB 29(22): 6059-73, 2009)

1) Start with the problem: It is tempting to start with cumbersome amounts of background information in the abstract. It is also tempting to present early on why the work is significant. Rather than beginning by dwelling on the importance of your study or describing what is already known in a pathway or system, introduce your work by presenting the problem right away. This immediately provides the associate editor and expert reviewer something to grasp. The problem should be offered up in the second or third sentence as in the example:

Respiratory complex I (NADH:ubiquinone oxidoreductase) is a large mitochondrial inner membrane enzyme consisting of 45 subunits and 8 iron-sulfur (Fe/S) clusters. While complex I dysfunction is the most common reason for mitochondrial diseases, the assembly of complex I and its Fe/S cofactors remains elusive.

2) Give the solution: Immediately after the unknown being addressed, the solution found by the authors is offered up in this abstract’s next sentence:

Here, we identify the human mitochondrial P-loop NTPase, designated huInd1, that is critically required for the assembly of complex I.

It is a common and effective practice to use “Here we show…“, or a rendition thereof, to clearly state the major finding(s) of the paper. In this example the authors have used “Here, we identify…“. This language in the abstract will stick out right away to a savvy reader, telling him or her what your “take home” message is.

3) Include pertinent details: It is crucial that a reader knows certain important features of your work when deciding to dive further in. Another important consideration is that PubMed and other search engines, such as Google Scholar, will identify wording from the abstract when searches are performed. Therefore, the information in the abstract is critical to not only inspire reviewers and colleagues to read further but also to get your abstract in front of your potential audience.

One important feature that should appear in your abstract is your model. Are you using an organism, cell line, in vitro system? This is particularly important if there is not much use of your model in the literature. Nonetheless, it is necessary to provide this detail in the abstract. I have often been frustrated as a reader when yeast or a mammalian cell lines are used in a study, but not mentioned until the Methods or Results section. In the example abstract, details of the experimental system are present midway through the paragraph:

Knockdown of huInd1 in HeLa cells by RNA interference technology led to strong decreases in complex I protein and activity levels, remodeling of respiratory supercomplexes, and alteration of mitochondrial morphology.

4) Have conviction, but do not over-interpret: As with the title, it will annoy a Reviewer if you make bold claims in the abstract that are not fully substantiated by the results. However, avoid hedging in the abstract as it will suggest that you do not have strong evidence to back up your conclusion(s).

In the example, the authors write, “Together, these data identify huInd1 as a new assembly factor for human respiratory complex I with a possible role in the delivery of one or more Fe/S clusters to complex I subunits.” The statement, “these data identify” exhibits the strong commitment that the authors have to their conclusions, while “with a possible role” suggests that the data supporting the latter claim are not quite as convincing. Had the authors written something like, “these data are consistent with the hypothesis that huInd1 is…”, followed by the “with a possible role” statement, all the conclusions of the study would appear weak. Therefore, it is best if you can avoid hedging devices, such as “may” and “could”, and replace weaker verbs, such as “suggests” or “is consistent with” or “supports” with stronger ones such as, “identifies”, “indicates”, or “shows”.

5) Finish strong: The sentence quoted in section #4 above is the final one of the abstract. It doesn’t merely rehash the solution, but it provides an interpretation of the major conclusions, framing them into a working model. Quite often, this final statement of the abstract will be a re-wording of the paper’s title. Some journals mandate that the authors divide their abstracts into sections, with the final section labeled the “conclusion”. Readers will often look at this section first, and then decide if they will devote more time to the paper. With this in mind, it becomes clear why a strong finish, especially one with the term “conclude” or “conclusion” used outright, is important.