Bacitracins

Bacitracins (BCs) are peptide antibiotics produced by Bacillus subtilis and Bacillus licheniformis. They exhibit an inhibitory activity against Gram-positive bacteria and are most commonly used as animal feed

Table 2 Partition coefficients of SVD components with n-butanol systems n-Butanol/ diethyl ether/water

Partitioncoefficients (UL 1)

Figure 2 HPLC separation of sporaviridins. Column, Cosmosil 5C18 (5 |im, 4.6x150 mm); mobile phase, methanol/lmol L~1 ammonium chloride (74:26); flow rate, 1 mLmin~1; detection, 232 nm. (Reproduced with permission from Oka H etal. (1998).)

n-Butanol/ diethyl ether/water

Partitioncoefficients (UL 1)

C2

B2

A2

C1

B1

A1

10:

0

10

2.96

6.41

6.65

4.87

8.81

9.09

10:

3

:10

0.96

2.17

2.78

1.84

3.34

4.19

10:

4

:10

0.50

1.12

1.59

1.04

1.85

2.91

10:

5

:10

0.38

0.78

1.11

0.74

1.25

2.12

10:

6

:10

0.39

0.90

1.19

0.81

1.39

1.70

10:

7

:10

0.24

0.63

1.10

0.59

1.08

1.82

10:

4

:11

0.31

0.89

1.24

0.70

1.50

2.00

10:

4

12

0.38

1.09

1.41

0.80

1.85

2.32

10:

4

:13

0.37

1.05

1.51

0.73

1.58

2.10

10:

4

:14

0.29

1.09

1.17

0.57

1.22

1.74

Reproduced with permission from Harada K-I et al. (1990) and Oka H etal. (1998).

Figure 3 HPLC separation of sporaviridin components. For experimental conditions, see legend to Figure 2. (Reproduced with permission from Oka H etal. (1998) and Harada K-I etal. (1990).)

additives. Over 20 components are present in the bacitracin complex (Figure 4) among which BC-A and BC-B are the major antimicrobial components. BC-F is a degradation product and has nephrotoxicity. Only the structures of BC-A and -F have been determined (Figure 5).

We examined three groups of two-phase solvent systems containing w-butanol, ethyl acetate or chloroform as a major organic solvent, and ethanol and/or methanol as a modifier against water in each group. The w-butanol system produced suitable K values for peaks 13-18 whereas those for peaks 20-22 are too large. The ethyl acetate system represented by ethyl acetate/ethanol/water showed a long settling time, suggesting poor retention of the stationary phase in the column. The most promising results were obtained from the chloroform, ethanol and/or methanol, water systems as summarized in Table 3. Among all combinations for the solvent volume ratio, chloroform/ethanol/ methanol/water (5:3:3:4) and chloroform/ethanol/water (5:4:3) gave the most desirable K values.

Figure 4 HPLC separation of bacitracins. Column Capcel Pak C18 (5 ^m, 4.6x150 mm); mobile phase, methanol/0.04 mol L 1 sodium dihydrogen phosphate (6:4); flow rate, 1.3 mL min~1; detection, 234 nm. (Reproduced with permission from Oka H etal. (1998) and Harada K-I etal. (1991).)
Figure 5 Structures of bacitracins A and F. (Reproduced with permission from Harada K-I et al. (1991) and Oka H et al. (1998).)

Figure 6 shows the countercurrent chromatogram of bacitracin components using the chloroform/ ethanol/methanol/water (5:3:3:4) system. A 50 mg amount of the bacitracin complex was loaded into the HSCCC column. The retention of the stationary phase was 72.7% and the elution time was about 3 h. All components were eluted in an increasing order of their partition coefficients, yielding 5.5 mg of BC-A from peak 18 and 1.5 mg of BC-F from peak 22.

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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