Antibacterial Activity of Sulfated Galactans from Eucheuma serra and Gracilari verrucosa against Diarrheagenic Escherichia coli via the Disruption of the Cell Membrane Structure

Abstract

Seaweed sulfated polysaccharides have attracted significant attention due to their antibacterial activity. This work investigated the antibacterial activity and mechanism of depolymerized sulfated galactans from Eucheuma serra (E. serra) and Gracilaria verrucosa (G. verrucosa) against enterotoxigenic Escherichia coli (ETEC) K88. The results show that removing the metal ions improves the anti-ETEC K88 activity of the galactans. The fluorescence labeling study confirmed that the sulfated galactans penetrated the cell walls and eventually reached the interior of the ETEC K88. Nucleic acid staining and intracellular protein leakage were also observed, indicating the destruction of permeability and integrity of the cell membrane. Interestingly, the two polysaccharides exhibited no effect on the proliferation of the selected Gram-positive bacteria and yeast. This indicates that the cell wall structure of the microorganisms could influence the bacteriostatic activity of the sulfated polysaccharides, as well. These results suggest that the sulfated seaweed polysaccharides might have potential application value in antibacterial diarrhea.

Bibliometric Analysis of Marine Traditional Chinese Medicine in Pharmacopoeia of the People’s Republic of China: Development, Differences, and Trends Directions

“…For example, Margaritifera Concha has now been demonstrated to be effective against influenza and herpes viruses [ 108 ]. Pharmacological effects, such as inflammation [ 109 ], an anticoagulant effect [ 110 ], an antiallergic [ 111 ], an antibacterial [ 112 ], and even the treatment of obsessive-compulsive disorder [ 113 ], etc., have all been verified.…”

Preventive Effect of Depolymerized Sulfated Galactans from Eucheuma serra on Enterotoxigenic Escherichia coli-Caused Diarrhea via Modulating Intestinal Flora in Mice

“…The intestinal flora and its short-chain fatty acid (SCFAs) metabolites play an essential role in many inflammatory and immune diseases, such as arthritis, asthma, inflammatory bowel disease, allergic diseases, and colon cancer [ 39 ]. According to recent studies, DESP can specifically inhibit the growth of ETEC-K88 but have no such effect on probiotic bacteria [ 40 ], exhibiting the potential for treating bacterial diarrhea induced by ETEC-K88. Therefore, it is worth exploring the mechanism of DESP involved in bacterial diarrhea from the perspective of intestinal flora.…”

“…Interestingly, the growth of these two Gram-negative bacteria was inhibited by the anionic polysaccharide DESP. Furthermore, previous research confirmed that DESP can specifically inhibit the growth of Gram-negative bacteria, ETEC, but has no noticeable effect on the growth of Gram-positive bacteria and yeast [ 40 ]. This study showed that, compared with the model group, DESP effectively enriched the abundance of Lactobacillaceae , Bifidobacteriaceae , and Lachnospiraceae and inhibited the growth of Enterobacteriaceae and Bacteroidaceae in intestinal, which is similar to the regulation of fucoidan on the intestinal flora [ 58 ].…”

“…The DESP was obtained according to the methods described in our previous studies [ 22 , 40 ]. Briefly, the sample was washed with tap water to remove sand, salt, and epiphytes.…”

Identification of Potential Inhibitors of MurD Enzyme of Staphylococcus aureus from a Marine Natural Product Library

“…Therefore, Figure 8 shows the workflow of this study. In this study, a virtual screening of the marine small molecule library was initiated to identify a new S. aureus inhibitor from the marine small molecule library [30,31]. Through virtual screening, similarity screening and ADME drug analysis, we finally selected 46604 and 46608 as possible drug molecules targeting MurD enzyme of S. aureus.…”