FEB 08, 2017 12:02 PM PST

Marine sponge makes antibiotics

WRITTEN BY: Kerry Evans

Researchers are always on the lookout for new antibiotics, particularly ones that can kill antibiotic-resistant bacteria like methicillin-resistant Staphylococcus aureus (MRSA). As luck would have it, investigators at Florida Atlantic University isolated a compound from a marine sponge and found that it kills MRSA and Mycobacterium tuberculosis.

 

MRSA is probably the most well-known antibiotic-resistant bacterium out there. It is resistant to all beta-lactam antibiotics and causes more than 80,000 infections each year in the US - more than 11,000 of these are fatal.

 

The sponge in question belongs to the genus Spongosorites. These sponges are bright yellow, and have a thick, shiny, rubbery crust. The compound that Wright and colleagues isolated is an indole alkaloid that they named “dragmacidin G.” Other compounds isolated from sponges in this genus are antifungal, antiplasmodial, or anti-inflammatory.

 

A sponge from the genus Spongosorites - Habitas.org.uk

 

According to study author Amy Wright, “we found substantial antibacterial activity for dragmacidin G. It is greater than 10-fold more potent than other members of the bis-indole alkaloids while retaining selectivity towards bacterial over mammalian cells."

 

The group collects natural products from marine organisms and banks them in a library. Then, they test this library of compounds for activity against various diseases. According to Wright, “the primary goal of our marine biomedical and biotechnology program is to discover marine natural products with utility as medicines or as tools to better allow us to understand disease processes.”

 

In the current study, the researchers determined the minimum inhibitory concentration (MIC) of dragmacidin G required to kill MRSA, M. tuberculosis, P. falciparum, and mammalian cells. The MIC was 1uM for MRSA and 21uM for M. tuberculosis, whereas 125uM dragmacidin G was required to kill J744 macrophages.

 

They also tested dragmacidin G against P. falciparum, the parasite that causes malaria. The IC50 for P. falciparum was 6.4uM, and this was similar to the IC50 of 7.8 for mouse fibroblasts - this means that dragmacidin G is not selective for P. falciparum.

 

Although dragmacidin G selectively kills MRSA and M. tuberculosis, its toxicity and efficacy need to be established in an animal model before it can be considered as a new antibiotic.


Sources: Marine Drugs, Science Daily, Habitas.org.uk

 

 
About the Author
  • Kerry received a doctorate in microbiology from the University of Arkansas for Medical Sciences.
You May Also Like
JUL 17, 2018
Microbiology
JUL 17, 2018
Understanding how Microbes Will Accelerate Climate Change
As permafrost starts to thaw out, it's exposing untold numbers of new bacteria, which can spew out methane....
JUL 17, 2018
Videos
JUL 17, 2018
Novartis Ends Antibiotic Research
The United Nations has warned that by 2050, antibiotic-resistant microbes might kill ten million people every year....
JUL 21, 2018
Cell & Molecular Biology
JUL 21, 2018
Revving the Nanomotor
Many people have never heard of cilia, but these tiny appendages are an essential part of the cell....
AUG 13, 2018
Microbiology
AUG 13, 2018
Insight Into the Origins of Junk DNA - From Koalas
The human genome isn't only genes. There's also long, repetitive sequences with an unknown function and origin....
AUG 27, 2018
Genetics & Genomics
AUG 27, 2018
A Better Way to Classify Bacteria
The classification of organisms into groups, taxonomy, has taken an important step forward....
SEP 12, 2018
Microbiology
SEP 12, 2018
Researchers ID a Link Between a Bacterial Strain and Gastric Cancer
Helicobacter pylori is a bacterium that causes stomach ulcers, and can lead to gastric cancer....
Loading Comments...