Exopolysaccharide (EPS) was produced by Lacticaseibacillus paracasei ZY-1 isolated from Tibetan kefir grains, and the preliminary structure of two EPS fractions (EPS1 and EPS2) was investigated. NMR analysis revealed that the backbone of higher producing EPS1 was consisted of →6)-α-D-Manp-(1→, →2,6)-α-D-Glcp-(1→, α-D-Manp-(1→, →2)-α-D-Glcp-(1→, →3)-α-D-Manp-(1→, →6)-α-D-Glcp-(1→. Furthermore, an eps gene cluster that encodes the glycosyltransferase and relevant proteins for EPS biosynthesis was identified on the basis of bioinformation analysis of the complete genome. RT-qPCR results indicated that wzd (ZY-1_2260) and wze (ZY-1_2259) might be essential genes involved in EPS production. Meanwhile, the synthetic mechanism of EPS1 in L. paracasei ZY-1 was further proposed. Besides, the crude and purified EPS showed certain scavenging activities against DPPH, hydroxyl and ABTS radicals. Results provided a better understanding of EPS biosynthesis in L. paracasei ZY-1 at the gene level.

biosynthesis, eps gene cluster, Structural characterization, exopolysaccharide (EPS), Lacticaseibacillus paracasei ZY-1

13C NMR data:
Linkage	Residue	C1	C2	C3	C4	C5	C6
6,2,6	aDManp	99.81	71.67	73.41	74.63	71.33	66.30
6,2,2,3	aDManp	102.22	70.11	71.33	69.85	70.73	60.71
6,2,2	aDManp	102.10	69.60	78.05	71.63	71.38	60.71
6,2	aDGlcp	100.61	78.48	70.62	73.41	71.33	67.06
6	aDGlcp	98.35	78.74	71.67	70.03	73.41	62.74
	aDGlcp	98.65	71.63	73.28	70.85	73.41	67.82


1H NMR data:
Linkage	Residue	H1	H2	H3	H4	H5	H6
6,2,6	aDManp	5.42	3.63	3.97	3.65	3.87	3.81
6,2,2,3	aDManp	5.17	4.10	3.87	4.26	3.90	3.85
6,2,2	aDManp	5.07	4.24	3.97	3.67	3.85	3.88
6,2	aDGlcp	5.31	4.14	3.92	3.79	3.87	3.67
6	aDGlcp	5.11	4.05	3.63	3.70	3.97	3.72
	aDGlcp	4.99	3.62	3.81	3.89	3.79	3.94


1H/13C HSQC data:
Linkage	Residue	C1/H1	C2/H2	C3/H3	C4/H4	C5/H5	C6/H6
6,2,6	aDManp	99.81/5.42	71.67/3.63	73.41/3.97	74.63/3.65	71.33/3.87	66.30/3.81
6,2,2,3	aDManp	102.22/5.17	70.11/4.10	71.33/3.87	69.85/4.26	70.73/3.90	60.71/3.85
6,2,2	aDManp	102.10/5.07	69.60/4.24	78.05/3.97	71.63/3.67	71.38/3.85	60.71/3.88
6,2	aDGlcp	100.61/5.31	78.48/4.14	70.62/3.92	73.41/3.79	71.33/3.87	67.06/3.67
6	aDGlcp	98.35/5.11	78.74/4.05	71.67/3.63	70.03/3.70	73.41/3.97	62.74/3.72
	aDGlcp	98.65/4.99	71.63/3.62	73.28/3.81	70.85/3.89	73.41/3.79	67.82/3.94

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

[*]OC[C@H]1O[C@H](OC[C@H]2O[C@H](O[C@H]3[C@@H](OC[C@H]4O[C@H]([*])[C@H](O)[C@@H](O)[C@@H]4O)O[C@H](CO)[C@@H](O)[C@@H]3O)[C@H](O[C@H]3O[C@H](CO)[C@@H](O)[C@H](O[C@H]4O[C@H](CO)[C@@H](O)[C@H](O)[C@@H]4O)[C@@H]3O)[C@@H](O)[C@@H]2O)[C@@H](O)[C@@H](O)[C@@H]1O

972.846 g/mol (C₃₆H₆₀R₂O₃₀, R = next and previous repeats, not counted in mol weight)

Natural products of microbial origin have inspired most of the commercial pharmaceuticals, especially those from Actinobacteria. However, the redundancy of molecules in the discovery process represents a serious issue. The untargeted approach, One Strain Many Compounds (OSMAC), is one of the most promising strategies to induce the expression of silent genes, especially when combined with genome mining and advanced metabolomics analysis. In this work, the whole genome of the marine isolate Rhodococcus sp. I2R was sequenced and analyzed by antiSMASH for the identification of biosynthetic gene clusters. The strain was cultivated in 22 different growth media and the generated extracts were subjected to metabolomic analysis and functional screening. Notably, only a single growth condition induced the production of unique compounds, which were partially purified and structurally characterized by liquid chromatography high-resolution tandem mass spectrometry (LC-HRMS/MS). This strategy led to identifying a bioactive fraction containing >30 new glycolipids holding unusual functional groups. The active fraction showed a potent antiviral effect against enveloped viruses, such as herpes simplex virus and human coronaviruses, and high antiproliferative activity in PC3 prostate cancer cell line. The identified compounds belong to the biosurfactants class, amphiphilic molecules, which play a crucial role in the biotech and biomedical industry.

mass spectrometry, glycolipids, Marine bacteria, metabolomics, biosurfactant, Antiviral, antiproliferative, microbial natural products, OSMAC approach, trehalolipids

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

CCCCCCCC(=O)OC(CCC)CC(=O)O[C@@H]1[C@@H](O)[C@H](O[C@@H]2O[C@H](CO)[C@@H](O)[C@H](OC(=O)CCCCC)[C@H]2O)[C@@H](CO)O[C@@H]1O[C@H]1O[C@H](CO)[C@@H](OC(=O)CCC(=O)O)[C@H](O)[C@H]1OC(=O)CC(CCCCC)OC(=O)CCCCC

1183.342 g/mol (C₅₆H₉₄O₂₆)

Natural products of microbial origin have inspired most of the commercial pharmaceuticals, especially those from Actinobacteria. However, the redundancy of molecules in the discovery process represents a serious issue. The untargeted approach, One Strain Many Compounds (OSMAC), is one of the most promising strategies to induce the expression of silent genes, especially when combined with genome mining and advanced metabolomics analysis. In this work, the whole genome of the marine isolate Rhodococcus sp. I2R was sequenced and analyzed by antiSMASH for the identification of biosynthetic gene clusters. The strain was cultivated in 22 different growth media and the generated extracts were subjected to metabolomic analysis and functional screening. Notably, only a single growth condition induced the production of unique compounds, which were partially purified and structurally characterized by liquid chromatography high-resolution tandem mass spectrometry (LC-HRMS/MS). This strategy led to identifying a bioactive fraction containing >30 new glycolipids holding unusual functional groups. The active fraction showed a potent antiviral effect against enveloped viruses, such as herpes simplex virus and human coronaviruses, and high antiproliferative activity in PC3 prostate cancer cell line. The identified compounds belong to the biosurfactants class, amphiphilic molecules, which play a crucial role in the biotech and biomedical industry.

mass spectrometry, glycolipids, Marine bacteria, metabolomics, biosurfactant, Antiviral, antiproliferative, microbial natural products, OSMAC approach, trehalolipids

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

R1 = LIP
CCCCCCCC(=O)OC(CCC)CC(=O)O[C@@H]1[C@@H](O)[C@H](O[C@@H]2O[C@H](CO)[C@@H](O)[C@H](OC(=O)CCCCC)[C@H]2O)[C@@H](CO)O[C@@H]1O[C@H]1O[C@H](CO)[C@@H](O[1*]OC(=O)CCCCC)[C@H](O)[C@H]1OC(=O)CCC(=O)O

1057.143 g/mol (C₄₈H₈₀RO₂₅, R = residue superclass(es), not counted in mol weight)

Natural products of microbial origin have inspired most of the commercial pharmaceuticals, especially those from Actinobacteria. However, the redundancy of molecules in the discovery process represents a serious issue. The untargeted approach, One Strain Many Compounds (OSMAC), is one of the most promising strategies to induce the expression of silent genes, especially when combined with genome mining and advanced metabolomics analysis. In this work, the whole genome of the marine isolate Rhodococcus sp. I2R was sequenced and analyzed by antiSMASH for the identification of biosynthetic gene clusters. The strain was cultivated in 22 different growth media and the generated extracts were subjected to metabolomic analysis and functional screening. Notably, only a single growth condition induced the production of unique compounds, which were partially purified and structurally characterized by liquid chromatography high-resolution tandem mass spectrometry (LC-HRMS/MS). This strategy led to identifying a bioactive fraction containing >30 new glycolipids holding unusual functional groups. The active fraction showed a potent antiviral effect against enveloped viruses, such as herpes simplex virus and human coronaviruses, and high antiproliferative activity in PC3 prostate cancer cell line. The identified compounds belong to the biosurfactants class, amphiphilic molecules, which play a crucial role in the biotech and biomedical industry.

mass spectrometry, glycolipids, Marine bacteria, metabolomics, biosurfactant, Antiviral, antiproliferative, microbial natural products, OSMAC approach, trehalolipids

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

R1 = LIP
[1*]O[C@H]1[C@@H](O[C@H]2O[C@H](CO)[C@@H](OC(=O)Cc3ccccc3)[C@H](O)[C@H]2O)O[C@H](CO)[C@@H](OC(=O)CCC(=O)O)[C@@H]1O

559.497 g/mol (C₂₄H₃₁RO₁₅, R = underdetermined substituent(s), not counted in mol weight)