*4.8. Data Analysis*

Gene expression levels were normalized using the most stable reference genes in RT-qPCR using the sampling time 0 h (predawn) as the control condition for each experiment. Data were presented as mean ± standard error and statistical analyses were performed using the pairwise fixed reallocation randomization test by REST (*n* = 3 biological triplicate, *n* randomizations = 2000, relative expression software tool) [76]. Relative expression ratios above 2-fold and with *p* value ≤ 0.05 were considered significant. NO and ROS data were presented as mean ± standard deviation and analyzed by Kruskal–Wallis with a Dunn's post hoc test (*n* = 3 biological triplicate). Kruskal–Wallis/Dunn's test and linear correlation analyses (Pearson) were performed using PAST software package, version 3.14 [77]. Graphs were built using GraphPad Prism software V 6.01.

### *4.9. Nitric Oxide Synthase (Nos) Protein Sequence Analysis*

The three *Homo sapiens* Nos protein sequences were downloaded from the NCBI protein database (iNOS-inducible: NP\_000616.3, eNOS-endothelial: BAA05652.1 and nNOS-neuronal: NP\_000611.1). The two *S. marinoi* (strain CCMP2092) Nos protein sequences were previously identified in *S. marinoi* [40], and were downloaded from the MMETSP website (Nos1 ID: MMETSP1039-20121108|3976\_1; Nos2 ID: MMETSP1039-20121108|3419\_1). The sequences were aligned using ClustalX and edited with GeneDoc software. The analysis of domains was performed using InterPro database.

**Supplementary Materials:** The following are available online at http://www.mdpi.com/1660-3397/18/9/477/s1, Figure S1: Protein sequence alignment of *S. marinoi* Nos's with human isoforms, Figure S2: *S. marinoi* growth curves, Table S1: *S. marinoi* cell growth rates and Table S2: Genes analyzed by RT-qPCR.

**Author Contributions:** Conceptualization, A.M., I.C., C.B., A.P.; formal analysis, A.M.; funding acquisition, A.P.; investigation, A.M., I.O., A.S.; project administration, C.B., A.P.; resources, C.B., A.P.; supervision, I.C., A.N., C.B., A.P.; validation, A.M., I.O., A.S., I.C., A.N., C.B., A.P.; visualization, A.M.; writing—original draft preparation, A.M.; writing—review and editing, A.M., I.O., A.S., I.C., A.N., C.B., A.P.; All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding. A.M. and A.S. were supported by SZN Ph.D fellowships via the Open University.

**Acknowledgments:** We are grateful to Federico Corato from the Department of Research Infrastructures for Marine Biological Resources, SZN, for the set-up of the LED illumination system. We thank Florian P. Seebeck from the Department of Chemistry, University of Basel, for thiols determination analyses and for helpful discussion on an early draft of this work.

**Conflicts of Interest:** The authors declare no conflict of interest.
