Characteristics of the cultivable bacteria from sediments associated with two deep-sea hydrothermal vents in Okinawa Trough

Abstract

In this study, different culture-dependent methods were used to examine the cultivable heterotrophic bacteria in the sediments associated with two deep-sea hydrothermal vents (named HV1 and HV2) located at Iheya Ridge and Iheya North in Okinawa Trough. The two vents differed in morphology, with HV1 exhibiting diffuse flows while HV2 being a black smoker with a chimney-like structure. A total of 213 isolates were identified by near full-length 16S rRNA gene sequence analysis. Of these isolates, 128 were from HV1 and 85 were from HV2. The bacterial community structures were, in large parts, similar between HV1 and HV2. Nevertheless, differences between HV1 and HV2 were observed in one phylum, one class, 4 orders, 10 families, and 20 genera. Bioactivity analysis revealed that 25 isolates belonging to 9 different genera exhibited extracellular protease activities, 21 isolates from 11 genera exhibited extracellular lipase activities, and 13 isolates of 8 genera displayed antimicrobial activities. This is the first observation of a large population of bacteria with extracellular bioactivities existing in deep-sea hydrothermal vents. Taken together, the results of this study provide new insights into the characteristics of the cultivable heterotrophic bacteria in deep-sea hydrothermal ecosystems.

A First Study of the Virulence Potential of a Bacillus subtilis Isolate From Deep-Sea Hydrothermal Vent

“…In situ temperature was measured using a conductivity-temperature-depth sampler. Seawater samples collected in situ were brought on board under totally enclosed condition and the outer surface of the sampling bottle was immediately disinfected with 75% alcohol before taking the water from the bottle; after being taken from the sampling bottle, the seawater was immediately used for bacterial isolation in an ultra-clean workbench on board as follows: 100 μl of the seawater was plated on marine agar 2216E medium (Sun et al, 2015) in an aseptic environment and incubated under aerobic conditions at 4°, 15°, 28°, or 40°C for 7 d. The colonies on the plates were screened by their shape, size, margin, color, and opacity (Valiente Moro et al, 2013). Each type of colonies was selected for purification.…”

Characterization of the Genome Feature and Toxic Capacity of a Bacillus wiedmannii Isolate From the Hydrothermal Field in Okinawa Trough

“…For bacterial isolation, the gills were immediately removed from the shrimp and homogenized in PBS. The homogenate was plated on marine agar 2216E medium (Sun et al, 2015), and the plates were incubated at 28°C for 2–3 days under aerobic conditions. The colonies on the plates were screened according to their shape, size, margin, color, and opacity (Valiente Moro et al, 2013).…”

“…The purified isolates were resuspended in marine 2216E medium containing 15% (v/v) glycerol and stored at −80°C. The species identities of the isolated bacteria were determined based on 16S rRNA gene sequence as reported previously (Sun et al, 2015). A total of 30 isolates were obtained, including three isolates belonging to the genus Bacillus and one isolate belonging to B. cereus group, which was named SR52.…”

Optimization of Lipase production from a novel strainThalassospira permensisM35-15 using Response Surface Methodology

“…Some deep-sea bacteria producing lipases have been reported in several papers. [14][15][16] According to a report of Odisi et al, among the 161 strains from sediment and water column in South Atlantic 14.3% strains exhibited lipolytic activities. The amount of lipolytic bacteria in sediment was larger than that in the water column.…”