Search for new bacteria leads researchers to extreme environments

Noêmia Lopes/Agência FAPESP/DICYT Collecting bacteria in the marine abyss at depths of more than 10,000 meters or in extremely arid deserts at heights of up to 5,000 meters is the strategy behind the field work conducted by researchers at the School of Biosciences of the University of Kent in the United Kingdom.

“We believe that in places such as those, we can find new organisms that have new chemical and biological properties that, in turn, can give rise to new antibiotic, anticancer and antioxidant drugs. Up to now, our findings have confirmed that hypothesis,” researcher Alan Bull told Agência FAPESP. As a member of the group, he adds his 20 years of field experience to the group’s work.

Bull was one of the speakers at the International Symposium Biota Microorganisms held at FAPESP from April 28 - 30, 2014.

During his talk, Bull presented work that involved searching, collecting and isolating samples in order to conduct phenotypic and genotypic analyses of the bacteria that belong to the phylum Actinobacteria.

“Since the emergence in the late 1940s of the first antibiotics with clinical application – Penicillin and Streptomycin derived from a fungus and an actinobacterium, respectively – research has been conducted in an effort to discover new species from those groups. The more we look, the more interesting organisms and chemical properties we find,” Bull said.

Traditionally considered to be soil and freshwater bacteria, actinobacteria have also been found in the extreme environments visited by Bull and his partners. These researchers also confirmed that the actinobacteria they collected have an exceptional capacity to produce compounds with a wide range of bioactivities.

The species Verrucosispora maris, collected from the depths of the Sea of Japan, appear to researchers to be very promising. It produces a compound known as atrop-Abyssomicin C that has anti-tuberculosis and antibacterial actions as well as anti-MRSA (Methicillin-resistant Staphylococcus aureus) action.

The species Verrucosispora fiedleri was collected from the depths of the Raune Fjord, in Norway, and has been shown to possess compounds with antitumor activities.

The actinobacterium Dermacoccus abyssi was collected from the Pacific Ocean’s Mariana Trench, 10,894 meters below sea level. Analyses of its compounds have confirmed anticancer, anti-trypanosome and radical-scavenging activities.

By contrast, researchers have also collected samples in dry and extremely dry regions, such as the Atacama Desert in northern Chile. “Some parts of these types of deserts are completely devoid of vegetation; there are very few animals and almost no birds. Are there any bacteria? The answer is ‘yes.’ They are only found in small numbers, but there is significant diversity,” said Bull.

Streptomyces leeuwenhoekii, an actinobacterium found in the soils of the Salar de Atacama, is one example of this diversity. Its Chaxamycins compound also have antibacterial and anticancer activities.

Collections were also obtained in Australia (Kings Canyon), on the African continent (Namib Desert), in the Atlantic Ocean (Canary Basin) and Indian Ocean (Indus Rise), in other parts of the Pacific Ocean (Sagami Bay, Suruga Bay, Ryukyu Trench and Izu-Ogasawara Trench) and even in Antarctica (Edmundson Point).

The University of Kent researchers collaborated with teams from various countries, such as Japan, Chile, Germany and The Netherlands, as well as institutions such as the British Royal Society and the Leverhulme Trust.

“We have found great novelties and many species that were not yet known, some of which have new chemical properties that we hope can lead to the development of new drugs. The challenge is in this last step, which will require millions of dollars in investments for long periods of time. But the compounds are very promising. We’re optimistic that one day they can become therapeutic drugs and lead to other investigations in the field,” Bull concluded.