On 2016 Oct 13, Ilana Kolodkin-Gal commented:

The supporting material for this paper was corrected, and the source data were provided to the editors of the Science journal. As for D-amino acids and biofilm formation: Non-canonical D-amino acids are small molecules interfering with cross-linking and transglycosylation of the peptidoglycan (Lam et al., 2009; Cava et al., 2011), and have been shown to trigger biofilm disassembly (Kolodkin-Gal et al., 2010), without affecting planktonic growth. This observation was later reproduced in various model organisms, such as Staphylococcus aureus (Hochbaum et al., 2011; Sanchez et al., 2013), Pseudomonas aeruginosa (Yu et al., 2012; Sanchez et al., 2014), the plant pathogen Xanthomonas citri (Li and Wang, 2014) , Escherichia coli (Xing et al., 2015) and in mixed biofilms (Si et al., 2014), as well as in other models published in numerous more recent publications. Furthermore, in our group we have generated so far two independent peer-reviewed publications clarifying the mode of action of D-aa for biofilm inhibition: http://onlinelibrary.wiley.com/doi/10.1111/1758-2229.12346/abstract http://www.jove.com/video/54612/methodologies-for-studying-b-subtilis-biofilms-as- Lastly, we established a consistent and robust experimental framework to study the effect of these small molecules biofilm inhibitors (Bucher et al., 2016).

On 2016 Sep 19, Morten Oksvold commented:

Please note that a rather extensive correction was published 7 December 2011: "The wrong images were mistakenly presented for day 3 for the wild-type and the racX ylmE double mutant in figure S4. The original and correct images are now shown. Also, the wrong image was presented for the mixture of L-amino acids in panel B of fig. S13 and has now been removed."

In 2013, the Losick group published results showing that D-amino acids inhibited bacterial growth and the expression of biofilm matrix genes and that the strain they originally used to study biofilm formation (B. subtilis) has a mutation in the D-tyrosyl-tRNA deacylase gene, an enzyme that prevents the misincorporation of D-amino acids into protein (Leiman et al., 2013). In a B. subtilis strain, which has a working copy of this gene, D–amino acids did not inhibit biofilm formation. The conclusion from their study was that "the susceptibility of B. subtilis to the biofilm-inhibitory effects of D-amino acids is largely, if not entirely, due to their toxic effects on protein synthesis.

Does that mean that they no longer see D-amino acids as a specific mechanism to disassemble biofilms in B. subtilis but rather as nonspecific inhibitors of growth in some genetic backgrounds?

Leiman et al. (2013) make no comment on the ability of D-amino acids to inhibit biofilm formation in staphylococcus aureus and Pseudomonas aeruginosa, as claimed in this article. The whole concept of biofilm dissasembly by D-amino acids therefore appears confusing.

It was recently published an article showing that D-amino acids do not inhibit biofilm formation in Staphylococcus aureus (Sarkar S and Pires MM, 2015).

On 2016 Sep 19, Morten Oksvold commented:

Please note that a rather extensive correction was published 7 December 2011: "The wrong images were mistakenly presented for day 3 for the wild-type and the racX ylmE double mutant in figure S4. The original and correct images are now shown. Also, the wrong image was presented for the mixture of L-amino acids in panel B of fig. S13 and has now been removed."

In 2013, the Losick group published results showing that D-amino acids inhibited bacterial growth and the expression of biofilm matrix genes and that the strain they originally used to study biofilm formation (B. subtilis) has a mutation in the D-tyrosyl-tRNA deacylase gene, an enzyme that prevents the misincorporation of D-amino acids into protein (Leiman et al., 2013). In a B. subtilis strain, which has a working copy of this gene, D–amino acids did not inhibit biofilm formation. The conclusion from their study was that "the susceptibility of B. subtilis to the biofilm-inhibitory effects of D-amino acids is largely, if not entirely, due to their toxic effects on protein synthesis.

Does that mean that they no longer see D-amino acids as a specific mechanism to disassemble biofilms in B. subtilis but rather as nonspecific inhibitors of growth in some genetic backgrounds?

Leiman et al. (2013) make no comment on the ability of D-amino acids to inhibit biofilm formation in staphylococcus aureus and Pseudomonas aeruginosa, as claimed in this article. The whole concept of biofilm dissasembly by D-amino acids therefore appears confusing.

It was recently published an article showing that D-amino acids do not inhibit biofilm formation in Staphylococcus aureus (Sarkar S and Pires MM, 2015).

On 2016 Oct 13, Ilana Kolodkin-Gal commented:

The supporting material for this paper was corrected, and the source data were provided to the editors of the Science journal. As for D-amino acids and biofilm formation: Non-canonical D-amino acids are small molecules interfering with cross-linking and transglycosylation of the peptidoglycan (Lam et al., 2009; Cava et al., 2011), and have been shown to trigger biofilm disassembly (Kolodkin-Gal et al., 2010), without affecting planktonic growth. This observation was later reproduced in various model organisms, such as Staphylococcus aureus (Hochbaum et al., 2011; Sanchez et al., 2013), Pseudomonas aeruginosa (Yu et al., 2012; Sanchez et al., 2014), the plant pathogen Xanthomonas citri (Li and Wang, 2014) , Escherichia coli (Xing et al., 2015) and in mixed biofilms (Si et al., 2014), as well as in other models published in numerous more recent publications. Furthermore, in our group we have generated so far two independent peer-reviewed publications clarifying the mode of action of D-aa for biofilm inhibition: http://onlinelibrary.wiley.com/doi/10.1111/1758-2229.12346/abstract http://www.jove.com/video/54612/methodologies-for-studying-b-subtilis-biofilms-as- Lastly, we established a consistent and robust experimental framework to study the effect of these small molecules biofilm inhibitors (Bucher et al., 2016).