Thanks for the kind comments regarding the article on the effect of nanogold particles against the tapeworm Raillietina sp.

There were three major questions which are quite pertinent to the conducted study.

1) What is the exact mechanism by which the gold particles exert their physiological functions on the worms? In other words, how do these nanoparticles interact with the surface/tegument of the worm? Is the interaction purely physical, or physicochemical, or biological? Are they taken up - actively or passively - by the worm through its surface?

Response
The current communication is a prelude to the detailed scientific study being conducted in our lab. We are trying to find out the mode of action of the gold particles in our subsequent studies. Preliminary report suggests that the gold particles are absorbed by the tegument (of the worms), which also serves as their gastrointestinal interface, but conclusive studies are on to confirm the exact mechanism of absorption.

2) Will this vermicidal effect be same regardless of the process of the generation of gold nanoparticles, or, for that matter, the particular enzyme/biomolecular reducing agent used?

Response
The vermicidal effect was found to be dose-dependent. Since we had studied only one process of generation of the gold-nanoparticles we are not in a position to speculate about the aspect queried upon.

3) Is this action a specific property of elemental gold, or its nanomolecular form? In other words, will nanoparticles generated from other noble and non-noble elements work in the same way? If not, that is/are the special characteristic(s) that confer(s) the vermicidal ability to gold nanoparticles?

Response
If we understand properly, the query is related to the efficacy of elemental gold or nanogold particles isolated/generated from other sources, or, its commercially available form, as an anthelmintic agent. An in-depth analytical study is required to respond to this query. We are continuing our studies with nanogold particles / nanosilver particles, from other sources (including commercially available ones) and would come up with concrete evidence very shortly.

[Quite apart from these three questions, my confusion about the physiological action depicted in the paper was compounded because the authors also mention: 'Changes in the tegumental architecture on treatment with gold nanoparticles suggest that the phytopathogenic fungal products bring about permeability changes in the tegument of the cestodes.'

To my understanding, it would be difficult to reconcile this statement with the earlier one. What exactly is the role of the fungal products in killing the worm (beyond production of the gold nanoparticles)? The authors clearly mention in the methods that "... produced gold nanoparticles were separated out from the culture filtrate by centrifugation [...] and the settled nanoparticles were washed thrice with de-ionized water." I think it's safe to assume that fungal products were washed off the gold nanoparticle preparation at this point. So, where is the interaction between the worm and phytopathogenic fungal products at the later, 'treatment' step?

And if there is, indeed, none, i.e. no interaction between the fungal products and the worm, what was the necessity to devote two whole paragraphs in the introduction to the purported use of natural products against helminthic worm in 'traditional' medical systems? How exactly is that information relevant to this otherwise-interesting paper? (This is my question to the Editor and the reviewers as well.)]

Response
As our learned friend commented on the irrelevance of including the term “phytopathogenic fungal products” we would like to provide a benign explanation as to why we thought it would fit in here. The paragraphs devoted very well tries to establish the fact that, other than various synthesis procedures, fungal products can also be used as agents for the synthesis of nanogold particles. We elaborated a little on the green chemistry approach. “Microorganisms being a group of highly diversified organisms found in nature, fit in quite appropriately to this requirement. Their high sustainability under ambient conditions of temperature, pressure and acidity, are highly preferred for the green synthesis of gold nanoparticles. Among diverse microorganisms, many bacteria, actinomycetes and fungi [3], [4] have been reported to synthesize gold nanoparticles.”

[“what was the necessity to devote two whole paragraphs in the introduction to the purported use of natural products against helminthic worm in 'traditional' medical systems?”]

The inclusion of two whole paragraphs in the introduction was necessitated by the comments made by one of the reviewers of this article. The reviewer insisted on rewriting this section with additional references on enzyme activity, ultrastructural studies etc., to determine anthelmintic efficacy and to prove that these procedures are well established in literature. The manuscript that was submitted initially did not contain these paragraphs as we were doubtful about its relevance in this paper. But to conform to the reviewer comments we incorporated them in our revised manuscript.

As per the excerpt quoted above, I have gone through reputed dictionaries wherein the synonym of “purported” is mentioned.
Purported, adjective : said to be true or real but not definitely true or real.

Well before you make any comment on this subject you need to go through the literature where the use of natural products against flatworms has been well established by hundreds of peer-reviewed papers in reputed journals. Questioning all these studies made by authors for the last few decades is an act questionable in itself. We would be grateful if you could choose your words diligently and in a befitting manner, while commenting on a particular aspect. “Purported” definitely is a derogatory comment which should have been avoided. Casual comments like this dent the goodwill of the reputed institution you represent.