Table I
Primer design.
| Primer name | Sequence |
|---|---|
| 27F | 5′-AGAGTTTGATCCTGGCTCAG-3′ |
| 1492R | 5′-GGTTACCTTGTTACGACTT-3′ |
Table II
PCR Amplification Reaction System.
| Reagent | Volume |
|---|---|
| Genomic DNA (20 ng/μl) | 1.0 μl |
| 10× Buffer (containing 2.5 mM Mg2+) | 5.0 μl |
| Taq Polymerase (5 U/μl) | 1.0 μl |
| dNTP (10 mM) | 1.0 μl |
| 27F Primer (10 μM) | 1.5 μl |
| 1492R Primer (10 μM) | 1.5 μl |
| ddH2O | 39.0 μl |
| Total volume | 50.0 μl |
Table III
Polymerase Chain Reaction (PCR) Amplification Protocol.
| Pre-denaturation | Denaturation | Annealing | Extension | Final extension | Number of cycles |
|---|---|---|---|---|---|
| 95°C, 5min | 95°C, 30s | 58°C, 30s | 72°C, 1min 30s | 72°C, 7min | 35 |
Fig. 1.
The front and back morphology of 17 bacterial colonies.
Fig. 2.
Morphological diagram of 17 bacterial strains.
Fig. 3.
Phylogenetic tree constructed based on 16S rRNA gene sequences.
The values at the branch points are the bootstrap values calculated 1,000 times when constructing the phylogenetic tree; the scale 0.05 represents a 5% difference in calculations.
Table IV
Identification results of 17 bacterial strains.
| Strain No. | Scientific name | Query coverage | Identities | Sequence ID |
|---|---|---|---|---|
| CHF-2 | Streptomyces heliomycini | 100% | 99.22% | NR_041197.1 |
| CHF-3 | Streptomyces plumbiresistens | 100% | 99.21% | NR_044518.1 |
| CHF-5 | Streptomyces alfalfae | 100% | 98.79% | NR_147713.1 |
| CHF-6 | Streptomyces huasconensis | 100% | 100.00% | NR_178969.1 |
| CHF-7 | Streptomyces spiroverticillatus | 100% | 99.50% | NR_112582.1 |
| CHF-8 | Niallia nealsonii | 100% | 99.22% | NR_044546.1 |
| CHF-9 | Streptomyces alfalfae | 100% | 98.71% | NR_147713.1 |
| CHF-10 | Streptomyces kanamyceticus | 99% | 98.88% | NR_043822.1 |
| CHF-11 | Acinetobacter seifertii | 100% | 100.00% | NR_134684.1 |
| CHF-12 | Streptomyces alfalfae | 98% | 97.99% | NR_147713.1 |
| CHF-14 | Peribacillus frigoritolerans | 100% | 99.93% | NR_117474.1 |
| CHF-15 | Streptomyces alboniger | 100% | 99.35% | NR_043228.2 |
| CHF-16 | Streptomyces alfalfae | 100% | 97.59% | NR_147713.1 |
| CHF-17 | Streptomyces spiroverticillatus | 100% | 99.43% | NR_112582.1 |
| CHF-18 | Streptomyces spiroverticillatus | 100% | 99.50% | NR_112582.1 |
| CHF-19 | Pseudarthrobacter siccitolerans | 100% | 99.50% | NR_108849.1 |
| CHF-20 | Streptomyces aureus | 99% | 99.06% | NR_025663.1 |
Fig. 4.
Inhibitory activity of secondary metabolites of 17 strains against Staphylococcus aureus.
Fig. 5.
Inhibitory activity of secondary metabolites of 17 strains against Proteus vulgaris.
Fig. 6.
Inhibitory activity of secondary metabolites of 17 strains against Candida albicans.
Table V
Results of inhibition zone determination of antibacterial activity of strains.
| Strain No. | Bacteriostatic diameter/cm | ||
|---|---|---|---|
| Staphylococcus aureus | Proteus vulgaris | Candida albicans | |
| CHF-2 | – | – | – |
| CHF-3 | 1.52 | 1.56 | 1.55 |
| CHF-5 | 4.25 | – | – |
| CHF-6 | 2.27 | – | 2.52 |
| CHF-7 | 1.49 | – | – |
| CHF-8 | – | – | – |
| CHF-9 | 1.78 | 1.55 | – |
| CHF-10 | 2.11 | – | – |
| CHF-11 | 1.62 | 1.53 | 1.54 |
| CHF-12 | 3.34 | 3.35 | – |
| CHF-14 | 2.14 | 1.50 | 1.53 |
| CHF-15 | 1.20 | 2.73 | – |
| CHF-16 | 4.14 | 2.37 | – |
| CHF-17 | 1.49 | – | 1.72 |
| CHF-18 | 1.47 | 1.37 | 1.69 |
| CHF-19 | – | – | – |
| CHF-20 | 2.20 | – | – |
Fig. 7.
Test results of salt tolerance of 17 bacterial strains.
Table VI
Salt tolerance of 17 bacterial strains.
| Strain No. | NaCl concentration (g/l) | |||
|---|---|---|---|---|
| 25 | 50 | 75 | 100 | |
| CHF-2 | + | + | + | – |
| CHF-3 | + | – | – | – |
| CHF-5 | + | – | – | – |
| CHF-6 | + | + | + | – |
| CHF-7 | + | – | + | – |
| CHF-8 | + | – | – | – |
| CHF-9 | + | – | – | – |
| CHF-10 | + | – | – | – |
| CHF-11 | + | + | + | + |
| CHF-12 | + | – | – | – |
| CHF-14 | + | + | + | – |
| CHF-15 | + | + | – | + |
| CHF-16 | + | – | – | – |
| CHF-17 | + | + | – | – |
| CHF-18 | + | – | + | + |
| CHF-19 | + | – | + | – |
| CHF-20 | + | + | – | – |
Fig. 8.
Test results of alkali resistance of 17 bacterial strains.