Bacterial Flagellum versus Carbon Nanotube: A Review Article on the Potential of Bacterial Flagellum as a Sustainable and Green Substance for the Synthesis of Nanotubes
Round 1
Reviewer 1 Report
1) Figure 2 is not required, because it does not contain any significant information. Please delete figure 2.
2) Is it correct that Figure 3B is Caulobacter? C. crescentus has a comma shaped cell body. The authors should recheck the species carefully.
3) As I pointed out previously, ref. 17 reported that the speed limit “depends” on the number of stator units (line132). I strongly ask the authors to read all of the references carefully again.
Author Response
Please see the attachment. Thank you!
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The article was revised taking into account recommendation suggestions.
Author Response
Please see the attachment. Thank you!
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Thank you for the revision. I hope the review will be useful for many readers.
This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.
Round 1
Reviewer 1 Report
In this article, the authors compare the characteristics of the bacterial flagellum with those of carbon nanotube (CNT) and discuss their usefulness as a nanomaterial. In conclusion, they insist that the bacterial flagellum has many advantages over CNT. Although studies on application of such biomaterials to nanotechnology are important, there are a number of critical problems in this article. My concerns are listed below.
- The authors submitted this paper as a review article. Instructions for Authors of this journal says “Reviews: These provide concise and precise updates on the latest progress made in a given area of research.”. To follow this policy, the authors should be experts of the topic addressed in the article. For example, Kim group has been publishing intriguing papers on application of the bacterial flagellum as a bio-template (e.g., refs 20 and 23). In contrast, about 90 papers are cited in this paper, but I cannot find publications from the authors’ group. Since I may have missed, please indicate your own publications related to bacterial flagella, CNT, and/or bio-templates.
- The schematic shown in the right panel of Fig. 2 is not the bacterial flagellum but the eukaryotic flagellum, such as an animal sperm and Chlamydomonas. The structural difference between flagella of bacteria and eukaryotes is very clear and basic fact. This mistake spoils the credibility of this paper.
- I found number of problems of citation, leading to distrust of the authors’ expertise. For example, in line 110, why was Iwazawa et al 1993 (the publication year is wrong in the reference list) cited here? In the paper, the torque-generation mechanism was discussed based on the results of flagellar rotation measurements. In the same paragraph, ref 15 is the paper about elementary process of mechanochemical energy conversion of the bacterial flagellar motor; ref 16 showed the opposite results from the author’s description, showing the speed limit “depends” on the number of stator units. As there are too many such mistakes, I give up pointing out individually. I am afraid that the authors did not read the cited papers. To dispel such a doubt, they should confirm whether citations are appropriate.
- There also exists much wrong and inappropriate information about the bacterial flagella. For example, the mechanism of taxis behavior is explained in the section “Types of Flagella”, but it does not correct: the motor reversal from CCW to CW is caused by binding of the phosphorylated chemotaxis response regulator CheY-P; the abrupt reversal causes deformation of flagellar bundle accompanied by polymorphic transition of helical parameters of each flagellar filament, leading to tumbling . If the authors would like to explain the bacterial flagellum in detailed, I strongly ask them to learn knowledges of the bacterial flagellum in earnest again.
- There are many errors of English grammar. English proof reading by a native speaker is needed.
- Similar sentences are repeated many times, and ambiguous adjectives are frequently used. Drastic modification is required for the entire paper so that each subject is explained more scientifically.
Reviewer 2 Report
The article is well written.
I have some minor suggestions to make:
There is no mention about flagella isolation method. Maybe a brief mention could be useful.
Line 43 - 44 "The use of bacterial flagella in various applications in recent years has been a highly important research among scientists" - insert references to argue this.
Line 74 - 76 - "The main source of power that drive the motor of bacterial flagellar motor is ion motive force (IMF), where the power is produced by transmembrane electrochemical ion gradient and flagellar filament rotation
to produce thrust and momentum for the cell body to be propelled (8)" - the phrase is a little to long; could be reformulated.
Line 94 - "that the flagella that projected ..." - could be replaced by: "that the flagella which is projected ..."
Figure 3 caption could be reformulated: "Visualization by phase-contrast microscopy of gram-negative bacterial flagella: (A) Brucella melitensis and (B) Caulobacter crescentus. (C) Negative-staining TEM image of the sheathed polar flagellum of B. melitensis. Bar, 500 nm. (13).
Line 119: "to the motorThe ...." replace with: "to the motor. The ..."
Line 137 - 142: "If such flagels spin in counterclockwise motion, they can create a assembly that propels the organism in one direction, so if any of the flagella falls free and starts to spin in the direction of the clockwise movement in another movement, the organism will instead be in a tumbling motion that can contribute to the stationary motion of the organism because it will no longer travel in any particular direction." - is a little too long and could be reformulated.
Page 6 - "used in the design and manufacture of complex ,..." - remove the space between "complex" and ".
Page 7 - replace "externala peptide: with "external peptide"
Page 8 - "of the templates of flagella" could be replaced by: "of the flagella templates"
"TiO2" need to be replaced by "TiO2"
"into the surface of the bacterial flagella" - replace with "on the surface of the bacterial flagella"
Page 9 - "Bacterial flagella are self-assembled protein nanofibers which are highly prospective in synthesizing nanotubes to replace the nanotubes are now widely used in many areas which are the carbon nanotubes." - it is not clear; could be reformulated.
In table 4 "Types of Carbon Nanotubes (CNTs) and its attributes" - a schematic representation can be added to the column "Type of Carbon Nanotubes (CNTs)".
Caption "Figure 1: TEM image of single-walled carbon nanotubes (SWCNT)" -need to be renamed: "Figure 5: TEM image of single-walled carbon nanotubes (SWCNT)";
Caption "Figure 3: High resolution TEM (HRTEM) images of double-walled carbon nanotubes (DWCNTs)" - need to be renamed: "Figure 6: High resolution TEM (HRTEM) images of double-walled carbon nanotubes (DWCNTs)"
Caption: "Figure 2: TEM images of multi-walled carbon nanotubes (MWCNTs)" - need to be renamed: "Figure 7: TEM images of multi-walled carbon nanotubes (MWCNTs)"
Page 12 correct: "nanocarriersIn addition"
Page 13: "Carbon Nanotubes (MWNTs) can be used as effective H2O, NH3, CO2 and CO (49)" - it is not clear, need to be reformulated.
Page 16: "The introduction of multiwall carbon nanotubes ( MWCNTS) into the composite carbon fiber (CF)/epoxy resin network is basically two methods." - need to be reformulated: "The introduction of multiwall carbon nanotubes ( MWCNTS) into the composite carbon fiber (CF)/epoxy resin network is made using basically two methods."
Page 17: "GO.Overall," - insert a space between
Page 18: "an total length of 57 μm with a corresponding surface area of 9
μm2" - corrections: "a total length of 57 μm with a corresponding surface area of 9 μm2".
Word "Ergo,..." - maybe could be deleted, and the phrase begin with: "in this context, bacterial flagella...."
Page 22: "to be suitable to be used in the fabrication ..." could be replaced by: "to be suitable for the fabrication ..."
Reviewer 3 Report
Although the application of bacterial flagella may be of great interest, I cannot understand the physical and chemical structures, economical production methods, and versatility of these organic or silica/TiO2 nanotubes by reading the present manuscripts. The author should explain their advantages in more detail from the above view points, for example.
