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Dear authors,
As per the recommendations of our reviewers, with pleasure I inform you that the manuscript is accepted for publication. However, this is only the editorial acceptance and still needs some tasks to be completed before publication. Therefore, I advise you to be available for few days to avoid any delays in publication.
All the best for your future submissions.
[# PeerJ Staff Note - this decision was reviewed and approved by Xavier Pochon, a PeerJ Section Editor covering this Section #]
The Authors have sufficiently revised the manuscript, and in my opinion, it is ready for publication
I have no comments
I have no comments
I have no comments
Dear Authors,
Please do the needful and resubmit asap.
All the best
**Language Note:** The review process has identified that the English language must be improved. PeerJ can provide language editing services - please contact us at [email protected] for pricing (be sure to provide your manuscript number and title). Alternatively, you should make your own arrangements to improve the language quality and provide details in your response letter. – PeerJ Staff
The Authors sufficiently revised the manuscript in terms of content. I also suggest a careful and thorough language revision.
Experimental design including very high metal concentrations cannot be improved and this is main limitation of the manuscript.
The findings of this study are not new and quite obvious, but they contribute to the knowledge on the toxic effects of Pb and Cd on fish.
The manuscript is of average quality, and before publication (if the Editors decide to publish it), I suggest a careful language revision.
Dear authors,
Our reviewers appreciate your efforts for sincerely addressing the issues. However, some points still need to be addressed.
Please revise and resubmit asap.
All the best.
The Authors considerably revised their manuscript according to the comments provided by all reviewers. However, they did not address my comment concerning the concentrations of Pb and Cd in polluted natural waters:
"2. Please specify the concentrations of Cd and Pb in polluted natural waters, including the Yangtze River (based on literature)
Response: According to the literature (DOI 10.12029/gc20220331001), the heavy metal Cd content in the sediments of the main stream of the lower reaches of the Yangtze River is 0.98 mg/kg; the content of heavy metal Pb was 31.56 mg/kg."
The response contains single Pb and Cd data in the Yangtze sediments, not water. Please, include more data showing Cd and Pb levels in various contaminated waters (not sediments, since most sediment metal content is immobile and rarely soluble).
Experimental design including very high metal concentrations cannot be improved
The findings of this study are not new and quite obvious, but they contribute to the knowledge on the toxic effects of Pb and Cd on fish
I am not very enthusiastic about this manuscript, but the Authors performed a certain amount of work and obtained not very important but reliable results.
I have no comments!
I have no comments!
I have no comments!
I have no comments！
Dear authors,
Our expert referees found your manuscript interesting and appropriate to proceed further; however, they also had concerns on some points that should be addressed. Please incorporate changes/justify the comments and resubmit asap.
All the best
**PeerJ Staff Note:** Please ensure that all review, editorial, and staff comments are addressed in a response letter and that any edits or clarifications mentioned in the letter are also inserted into the revised manuscript where appropriate.
This study is very important, dealing with a serious environmental issue such as metal pollution in water bodies; however, I have some comments to improve the study to meet the standards of a high-quality scientific publication:
1- The manuscript needs careful revision, especially in typing abbreviations, which should be written only once beside full names.
2- The typing of the reference inside the text needs to be corrected to match the journal guidelines
3- Figure quality is poor, needs more clarification
1- Why didn't the authors use the liver and spleen organs in the experiment?
- The liver is the main detoxification organ in fish; it also exhibits high Cd enrichment
- The spleen, another primary immune organ, plays a role in blood filtration and haematopoiesis
2- The authors should study the impact of heavy metal pollution on fish genetics, immune-related genes, or some markers of genotoxicity to detect DNA damage, altered gene expression, weakened immune responses, and reduced reproductive success
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The manuscript entitled “The effects of the heavy metals cadmium and lead on six metabolic and immune-related enzymes in the loach (Misgurnus anguillicaudatus)” addresses an important issue regarding the biochemical impacts of cadmium and lead exposure on aquatic organisms, particularly Misgurnus anguillicaudatus. However, several significant concerns must be addressed:
Comment 1: The methodology lacks sufficient detail regarding experimental setup, including exposure concentrations, duration, replication, and water quality parameters (e.g., pH, temperature, and hardness). These factors are crucial to ensure reproducibility and contextualize the results.
Comment 2: The rationale behind selecting the specific six enzymes for metabolic and immune response evaluation is not well-explained. Please provide a clearer scientific basis or literature support for choosing these particular biomarkers.
Comment 3: The statistical methods are inadequately described. Clarify whether data normality and homogeneity of variance were tested. Specify the post-hoc tests used and provide exact p-values where possible. Graphs should include error bars.
Comment 4: The discussion is mostly descriptive and needs deeper interpretation. Clearly explain the physiological relevance of enzyme activity alterations under cadmium and lead stress. Compare findings with existing literature and explore possible mechanisms.
Comment 5: The manuscript requires thorough editing for grammar, clarity, and scientific tone. Several sections, especially the introduction and discussion, contain ambiguous or redundant statements. Consider restructuring some paragraphs for better logical flow.
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English is sufficiently understandable and unambiguous.
Available references concerning Cd and Pb toxicity to fish are abundant; the Authors used them sufficiently and appropriately.
The article structure is correct, and so are the figures and tables. Raw data are available in the supplemental files.
The results show higher toxicity of Cd compared to Pb, which is a well-known fact.
The toxicity of Cd and Pb to fish was extensively studied, and the literature on this subject is abundant. The mechanisms of Cd and Pb toxicity were well explained; thus, this research does not explore any new area. The authors used extremely high concentrations of Cd and Pb, which had never been observed in nature (even in highly polluted aquatic environments!).
The findings confirmed the well-known fact that cadmium is more toxic to fish than lead.
1. Please add the used Cd and Pb concentrations in the Abstract
2. Please specify the concentrations of Cd and Pb in polluted natural waters, including the Yangtze River (based on literature)
3. The authors used an indirect method of measuring enzyme activity. Why was a direct spectrophotometric measurement method (in organ supernatant) not used?
The study investigated the toxic effects of cadmium and lead on six enzymes across multiple visceral organs in Misgurnus anguillicaudatus by using enzyme histochemical staining and optical density analysis. The research is meaningful and addresses an important topic regarding the enzymatic responses of M. anguillicaudatus to cadmium and lead exposure. However, the manuscript has several issues in terms of scientific writing, the overall workload seems insufficient for a full-length research article, and the English expression requires careful revision by a native speaker or professional editing service to ensure clarity and readability. Major revision is needed.
The manuscript lacks sufficient detail regarding the experimental design. Specifically, it is unclear how many treatment groups were included, what concentrations of Cd and Pb were used in each group, and what the exposure duration was.
Please clarify whether both sexes were used, and if so, whether sex was considered as a variable during experimental design or data analysis. Since sex-based physiological differences may influence enzyme activity and stress responses to heavy metals, this information is critical for interpreting the results and ensuring reproducibility.
The phrase "anesthesia to death as our euthanasia method" is conceptually and grammatically unclear. Anesthesia and euthanasia are distinct procedures, although anesthesia may be part of the euthanasia process.
Please provide the specific model and manufacturer information for the frozen tissue sections.
The first part of the Results section, along with Figure 1, appears to be redundant with the subsequent results. The data presented in Figure 1 are either repeated or closely aligned with the findings described later. Consider removing this figure and merging the associated text into the following results.
Line 19-20: “belongs to the genus Misgurnus, Cobitidae, Cypriniformes”, change into “belongs to the genus Misgurnus (Cypriniformes, Cobitidae)”.
Line 24 The manuscript states that this study provides basic information for "environmental protection," but no data or analyses directly related to environmental monitoring, risk assessment, or ecological impact are presented.
Line 136 “We”?
Please ensure consistency in the chemical notation of lead and cadmium throughout the manuscript. The terms "Pb²⁺" and "Cd²⁺" are sometimes used, while elsewhere "Pb" and "Cd" appear.
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