Metabolic Adaptation to Sulfur of Hyperthermophilic Palaeococcus pacificus DY20341T from Deep-Sea Hydrothermal Sediments.

Xiang Zeng,Zongze Shao,Xiaobo Zhang

doi:10.3390/ijms21010368

Abstract

The hyperthermo-piezophilic archaeon Palaeococcus pacificus DY20341T, isolated from East Pacific hydrothermal sediments, can utilize elemental sulfur as a terminal acceptor to simulate growth. To gain insight into sulfur metabolism, we performed a genomic and transcriptional analysis of Pa. pacificus DY20341T with/without elemental sulfur as an electron acceptor. In the 2001 protein-coding sequences of the genome, transcriptomic analysis showed that 108 genes increased (by up to 75.1 fold) and 336 genes decreased (by up to 13.9 fold) in the presence of elemental sulfur. Palaeococcus pacificus cultured with elemental sulfur promoted the following: the induction of membrane-bound hydrogenase (MBX), NADH:polysulfide oxidoreductase (NPSOR), NAD(P)H sulfur oxidoreductase (Nsr), sulfide dehydrogenase (SuDH), connected to the sulfur-reducing process, the upregulation of iron and nickel/cobalt transfer, iron–sulfur cluster-carrying proteins (NBP35), and some iron–sulfur cluster-containing proteins (SipA, SAM, CobQ, etc.). The accumulation of metal ions might further impact on regulators, e.g., SurR and TrmB. For growth in proteinous media without elemental sulfur, cells promoted flagelin, peptide/amino acids transporters, and maltose/sugar transporters to upregulate protein and starch/sugar utilization processes and riboflavin and thiamin biosynthesis. This indicates how strain DY20341T can adapt to different living conditions with/without elemental sulfur in the hydrothermal fields.

Highlights

Deep-sea hydrothermal fields provide unique and diverse habitats for various microbes
The elemental sulfur can be reduced to hydrogen sulfide at a final concentration of 1.20 mM/L after 60 hours’ growth, whereas H2 production was not detected (Figure 1)
Sulfur metabolism is important for the energy flow of deep-sea hydrothermal vents [57]

Summary

Introduction

Deep-sea hydrothermal fields provide unique and diverse habitats for various microbes. In such a harsh extreme environment, sharp physical and chemical gradients arise as great challenges to their survival. Temporal changes with vent activity variation pose challenges. Vent microorganisms are supposed to adapt themselves to these environmental spatial and temporal changes, helping them to survive as the chimney begins to die out or spread to vent surroundings, thereby decreasing the temperature range and necessary chemical supplies. The elemental sulfur is abundant in the mixing zones and located far from the black, high-temperature vent chimneys [1] which can be used as electron sinks in fermentation processes carried out by many Thermococcales and some representatives of Desulfurococcales [2,3]. The addition of elemental sulfur enhances growth in Thermococcus and is essential to some strains [6,7]

Methods

Results

Conclusion