Fig. 1. An integrated view of the biology of Halobacterium species NRC-1 (Ref. [37]). Aspects of energy production, nutrient uptake, membrane assembly, cation and anion transport, and signal transduction are depicted. Several amino acids may be used as a source of energy, including arginine and aspartate, which are passed to the citric acid cycle via 2-oxoglutarate and oxaloacetate, respectively.

Fig. 2. Growth curve of H. salianrum cultured at a salt concentration of 3.5, 4.3, and 6.0 M (a), extended view of 3.5 M condition (b) (Ref. [56]) H. salinarum was harvested in the mid-exponential phase at 72 h of cultivation at 4.3 and 6.0 M NaCl, and 240 h at 3.5 M NaCl. From this growth curve, it was confirmed that 4.3 M of NaCl was optimum for growth of H. salinarum.

Fig. 3. Protein expression map of H. salinarum (Ref. [56]). Eighty microgram of proteins from cell lysate cultured at 4.3 M NaCl was loaded on IPG strip of pH 3–10 (a), 24 cm and separated on MultiPhor. The gel was visualized by silver staining. IEF was carried out for 30 min at 200 V followed by 1 min at 500 V, 1 h to 8000 V and 10 h at 8000 V to a total of 84,000 Vh on pH 3–10 IPG strips using the IPG phor. Most proteins were concentrated in the highly acidic region, around pH 4.2. SDS–PAGE was conducted on 12.5% polyacrylamide gel. (b) IEF using pH 3.5–4.5 ultrazoom IPG strips was carried out with the combined IPG phor/MultiPhor protocol for 148,725 Vh. Ultrazoom drystrip of pH 3.5–4.5 showed better resolution than drystrip of pH 3–10. (c) IEF was performed using pH 4.5–5.5 ultrazoom IPG strips.

Fig. 4. Growth curve of H. salinarum cultured in the media containing diesel (Ref. [58]). H. salinarum was cultured in 0% (control), 2 and 4% of diesel. H. salinarum survived in all of 0, 2, and 4% diesel media. Cells cultured in 2 and 4% of diesel media were reached to mid-exponential phase after 60 and 72 h, respectively, which were delayed compared to 48 h of control.

Fig. 5. 2-DE maps of cells cultured in the absence of diesel (a) and in the presence of 4% diesel (b) (Ref. [58]). Five spots were differentially expressed. Spots 1 and 2 were neo-expressed and spots 3–5 were up-regulated about nine-fold, three-fold, and 10-fold, respectively. Protein (80 μg) was loaded on IPG strip (pH 4–5, 24 cm) and SDS–PAGE was performed with a 12.5% gel. The gel was visualized by silver staining.

Fig. 6. Flow chart for the prediction of the function of unknown hypothetical proteins (Ref. [57]). Amino acid sequences were attained from H. species NRC-1 genome database. The website information for each program is shown in the text.

Fig. 7. Amino acid sequence alignment of ribosomal protein L12/L7, L3, and L13p (Ref. [57]). Amino acid sequences of ribosomal protein L3 from E. coli O 157 (top line), ribosomal protein L13p from H. salinarum (middle line), and ribosomal protein L12/7 from E. coli K12 (bottom line) were aligned using ClustalW program. Conserved N-terminal serine residues were highlighted by arrows.

Categories of Halophilic Microorganisms (Ref. [2])

Proteins identified by ESI-Q-TOF MS/MS which show a significant difference in expression with differences in the concentration of salt (Ref. [56] and [57])

Identification of differentially expressed protein spots of cells cultured in 4% diesel media by MS/MS analysis (Ref. [58])

Spots 3–5 were up-regulated spots about nine-fold, three-fold, and 10-fold, respectively. Mowse score is −10*log (p), where p is the probability that the observed match is a random event. Individual ion scores >50 indicate identity or extensive homology (p < 0.05).

Summary of predicted functions of Vng1088c (Ref. [58])

Predicted functions of 10 novel proteins