Sulfide Treatment Alters Antioxidant Response and Related Genes Expressions in Rice Field Eel (Monopterus albus)
, Fan Yao 1,2, He Zhang 3, Huaxiao Xie 1,2, Huijun Ru 1,2, Nian Wei 1,2, Zhaohui Ni 1,2, Zhong Li 1,* and Yunfeng Li 1,2,*Round 1
Reviewer 1 Report
This paper evaluated the potential toxicity effects of juvenile rice field eels exposed to sub-lethal concentrations of sulfide. The authors reported that sulfide had caused oxidative stress and physiological stress to rice field eels, which has environmental significance to the risk evaluation of sulfide. The manuscript is well organized and easy to follow. Overall, this is a nice work and I recommend that a revised manuscript be considered for publication in Water after the authors make major revisions based on following specific concerns.
1. Line 25 Remove the redundant parethesis.
2. Line 49 Remove the redundant “s”.
3. Line 58-63 Please unify the tense of these sentences.
4. Line 85-86 Change “…which made the nominal concentration consistent with the actual concentration…” to “…which made the actual concentration consistent with the nominal concentration…”
5. Line 91-95 No data about histopathological analysis was shown in the manuscript, please renewed these sentences.
6. Line 97 Change “The liver samples homogenized…” to “The liver samples were homogenized…”.
7. Line 115 Please provide amplification efficiency value for each gene in Table 1.
8. Line 139-140 “Exposure to higher concentration of Na2S…”, the descriptions in this sentence were confusing. Please carefully review and revise to be clear.
9. Line 153 It is not suitable to use “short time” in this sentence. Please give the time exactly.
10. Line 158 Change “…exposed to 2.154 and 21.54 mg/L…” to “…exposed to 2.154 and 21.54 mg/L Na2S…”.
11. In discussion part, the authors mentioned “higher sulfide dose” multiple times, please give the exposure concentrations exactly.
12. As far as I am concerned, Hsp70 has often been used as biomarker for physiological stress. Why did not measure hsp70 expression level in the present study.
13. The quality of the figures needs to be improved.
14. Findings in following references would be amendable to the present results and discussion, which are recommended to acknowledge herein (Environmental Science & Technology 2021, 55, 529−537; Environmental Science & Technology 2020, 54, 7494−7503; Environmental Science & Technology Letters 2018, 5, 731–738; Science of the Total Environment 2021, 799, 149458).
Author Response
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Author Response File: 
Author Response.docx
Reviewer 2 Report
This study provides physiological mechanisms for the stress response to sulfur compounds in rice eel. It would be enhanced by the addition of data about survival during the experiment: how well did the fish survive over the 3 weeks of the study? Also information about the levels of sulfide compounds in rice fields or other likely aquaculture environments would be a useful addition.
Figure 3 legend is not clear what the numbers mean, or the significance of graph 3D. Please provide more explanation.
Author Response
Please see the attachment.
Author Response File: Author Response.docx
