Introducing Methods and Results

How to introduce your protocols

Here is a bad introduction from a Materials and Methods section (section heading is in bold):

‘3-hydroxydecanoic acid (3HD) synthesized by various recombinant E. coli strains harboring tesB.  
In order to evaluate the functionality of thioesterase II in E. coli, pLZZH01 was digested with Cla I and
Hinc II.  
The 918-bp tesB gene fragment was inserted into the restriction sites of Cla I and Sma I in vector
pBBR1MCS-2, leading to plasmid pLZZH09 which contained tesB gene under the control of a lac promoter
(Fig. 1a). Various E. coli recombinants were incubated at 37ºC, 200 rpm for 48 h on a rotary shaker (Series 25
D, NBS, New Brunswick, USA) in LB medium….’

This is bad because the digestion does not tell us anything about the function of thioesterase II.  In reality, it is a
procedure that is used to prepare the DNA.  We should rewrite the opening sentences to first explain our
experiment:

‘3-hydroxydecanoic acid (3HD) synthesized by various recombinant E. coli strains harboring tesB.  
In order to evaluate the function of thioesterase II in E. coli, we determined the levels of 3HB produced by
various recombinant E. coli strains harboring tesB.
 pLZZH01 was digested with Cla I and Hinc II.  The 918-
bp tesB gene fragment was inserted into the restriction sites of Cla I and Sma I in vector pBBR1MCS-2, leading
to plasmid pLZZH09 which contained tesB gene under the control of a lac promoter (Fig. 1a). Various E. coli
recombinants were incubated at 37ºC, 200 rpm for 48 h on a rotary shaker (Series 25 D, NBS, New
Brunswick, USA) in LB medium containing…’

To introduce Results, Briefly Explain the Logic for your experiment in the first sentence:

Since HB did not accelerate progression of L929 cells through the cell cycle, leading to cell
proliferation, we considered the alternative explanation, that it prevented cell death, especially at high
cell density.
Cells were plated at high density (1×105cells/well), and 16 h later the serum was removed from the
medium to induce cell death.  For each time point, cell numbers was reported as the percentage of cells found in
cultures grown in the absence of serum +/- HB versus the number of cells found in cultures grown in the presence
of serum.  Cell death progressed at equal rates in both cultures for 20 h, stopped in the HB-treated cultures at 24
h, but continued in the control cultures (Fig. 3).  After 48 h, cell numbers were reduced by 60% in control
cultures, but only by 20% in HB-treated cultures (Fig. 3).

You may also speculate slightly from one set of Results to the next:

To assess the type of death inhibited by HB, FACS analysis of cells stained with annexin V and PI was
performed.  In this manner, the number of apoptotic (PI-negative and annexin V-positive) and dead (PI-positive
and annexin V-positive) cells were determined.  For apoptotic cells, no difference was observed between
treatments at any time point following serum withdrawal (Table 1).  There were significantly more dead cells at 48
and 72 h but not at 24 h following serum withdrawal in the control cultures versus the HB treatment.  Seventy two
hours after serum withdrawal, control cultures contained 2.41% apoptotic cells and 8.75% dead cells, while
cultures treated with HB contained 1.86% apoptotic cells and 3.25% dead L929 cells.

These results suggested that HB inhibited necrosis but not apoptosis.  We therefore assessed nuclear
morphology (apoptosis) and membrane integrity (necrosis) at various time points following serum-withdrawal for
cultures plated at different cell densities in 24-well plates:  1×104cells/well, 5×104cells/well, and 1×105cells/well.  
HB did not significantly inhibit apoptosis following serum-withdrawal (Fig. 4).  However, HB significantly reduced
cell membrane permeability for the 4 hour and all subsequent time points.  The greatest percentage of necrotic
cells were observed in the control cultures plated at 1×105cells/well, reaching 12% of the total by 24 h, nearly 3
times that observed for the 1×104cells/well and the 5×104cells/well (Fig. 4).  HB significantly reduced the
number of necrotic cells in cultures plated at 1×105cells/well to 8% of the total (Fig. 4).
Theory and Practice Home
This approach links the
current Results to the
previous Results and adds
cohesiveness to your
manuscript.
The second paragraph
very briefly discusses the
Results of the first
paragraph, introducing the
next topic.