Fig 1.
Physiological parameters of Spirulina under LT stress.
(A) The dry weight of cells. (B) The contents of chlorophyll a and carotenoid. (C) Soluble sugar content. (D) Proline content. The values represent the mean ± SD of three biological replicates. The asterisks indicate the significant differences that were calculated using the t-test (*P < 0.05; **P < 0.01).
Fig 2.
Identification and quantitative evaluation of identified proteins.
(A) Spectra, peptides, and proteins identified using Mascot. (B) Number of peptides matching the proteins identified by using MASCOT. (C) Distribution of identified proteins according to different molecular masses. (D) Peptide coverage of the identified proteins.
Fig 3.
GO classification of differentially expressed proteins in Spirulina under LT stress.
Fig 4.
Hierarchical clustering of differentially expressed proteins.
1–1 and 1–2 represent two biological replicates of the control group. 2–1, 2–2, and 2–3 represent three biological replicates of the treatment group. The columns represent individual proteins, and rows represent treatment groups. Red and blue indicate up-regulated and down-regulated levels, respectively, and white indicates no significant changes in the expression levels of proteins in response to stress.
Table 1.
KEGG pathway of most differentially expressed proteins.
Fig 5.
Carbon metabolism and amino acid biosynthesis are involved in the response of Spirulina to LT stress.
Red and green numbers represent the up- and down-regulated proteins, respectively. The abbreviations for the proteins are as follows: AMY, alpha-amylase; GlgP, glycogen phosphorylase; GlgB, 1,4-alpha-glucan branching enzyme; GlgA, glycogen synthase; GPI, glucose-6-phosphate isomerase; PFK, 6-phosphofructokinase; ALD, fructose-bisphosphate aldolase; GADPH, glyceraldehyde-3-phosphate dehydrogenase; PGK, phosphoglycerate kinase; PGM, phosphoglycerate mutase; ENO, enolase; PK, pyruvate kinase; PDHc, pyruvate dehydrogenase complex; CS, citrate synthase; ACO, aconitate hydratase; IDH, isocitrate dehydrogenase; OGDH, oxoglutarate dehydrogenase complex; SDH, succinate dehydrogenase; G6PD, glucose-6-phosphate-1-dehydrogenase; 6PGDH, 6-phosphogluconate dehydrogenase; TK, transketolase; TAL, transaldolase; FBPase, fructose-1 6-bisphosphatase; PRK, phosphoribulokinase; ALS, acetolactate synthase; GDH, glutamate dehydrogenase; GS, glutamine synthetase; HSD, homoserine dehydrogenase; ASL, argininosuccinate lyase; ArgD, acetylornithine aminotransferase; IPMS, 2-isopropylmalate synthase; IPMDH, 3-isopropylmalate dehydrogenase.