Fig 1.
Images of the alvinellid worm, Paralvinella hessleri.
A: A P. hessleri colonized hydrothermal vent in Iheya north hydrothermal field. The vent fauna showed apparent variation along the environmental gradients. The areas close to hydrothermal venting were covered with white mucus matt (P. hessleri colonies). The squad lobsters Shinkaia crosnieri occupied the areas surrounding the P. hessleri colonies (indicated by black arrowheads). Bathymodiolinae mussels stayed further away (indicated by white arrowhead); A’: Close-up image of P. hessleri worms close to the hydrothermal venting. B: A P. hessleri specimen with buccal tentacles extroverted, lateral view. Note that the animal has a bright yellow color; C: A close-up image of the notopod; D: A close-up image of the stem of branchial apparatus. Both panels C and D demonstrate that there are yellow granules in the epidermis of P. hessleri.
Fig 2.
Arsenic speciation and distribution between soluble and insoluble forms in P. hessleri.
A: Percentage of each arsenic species present in P. hessleri. B: soluble and insoluble arsenic in P. hessleri (n = 3). The data underlying Fig 2B can be found in S1 Data.
Fig 3.
Microscopy analysis of the yellow granules.
A: A longitudinally sectioned paraffin-embedded P. hessleri specimen, demonstrating the internal structure of the P. hessleri worm. B: Size distribution of the yellow granules in the major tissues of P. hessleri. C: Number of yellow granules per cell in the major tissues of P. hessleri. D: Cross section of branchial apparatus tip. E: Longitudinal section of P. hessleri branchial apparatus stem. F: Longitudinal section of P. hessleri body wall. G: Longitudinal section of P. hessleri buccal tentacles. H: Cross section of P. hessleri digestive tract. ASW: ambient seawater. ci: cilia. cu: cuticle. The data underlying Fig 3B and 3C can be found in S1 Data.
Fig 4.
SEM and TEM analysis of the yellow granules.
A: A SEM image of P. hessleri branchial apparatus; A’: A magnified region showing the electron-dense intracellular yellow granule. B: A SEM image of P. hessleri body wall; B’: A magnified region showing the electron-dense intracellular yellow granules. C: A SEM image of the digestive tract yellow granules. D: A TEM image of P. hessleri branchial apparatus. E: A close-up image of a typical branchial apparatus yellow granule. F: A TEM image of P. hessleri body wall; F’: A magnified region showing yellow granules and a secretion cell. G: A TEM image of buccal tentacles yellow granules; H: A TEM image of digestive tract yellow granules. ci: cilia; cu: cuticle, mt: mitochondria; gry: yellow granule, nu: cell nuclei.
Fig 5.
STEM-EDS mapping and micro-Raman spectrometry analysis of the yellow granules.
A: Bright-field STEM image of yellow granules in the fine tip of branchial apparatus; A’: A close up image of the STEM-EDS mapping scanning area; B–E: EDS mapping of Oxygen, Sulphur, Osmium, and Arsenic elements of the yellow granules; F: Merged image of Oxygen and Osmium EDS mapping; G: Merged image of Sulphur and Arsenic EDS-mapping; H: Optical image of branchial apparatus yellow granules for micro-Raman analysis; I: Raman spectra of yellow granules; Redcross in H micro-Raman spectrometry sampling point; Inset in I: Raman spectra from pure As2S3. The data underlying Fig 5I can be found in S2 Data.
Fig 6.
TEM analysis of the NaOH-treated P. hessleri tissues.
A: TEM image of NaOH-treated branchial apparatus; A’: A close-up image of yellow granules’ membrane structures and intra-membrane vacuoles; B: TEM image of two body wall yellow granules; B’: A close-up image showing the two sets of membranes, and numerous vesicles between the membranes; C: ci: cilia, cu: cuticle; gry: yellow granule; mt: mitochondria; nu: nuclei; black arrowhead: yellow granule; white arrowhead: mitochondria; double line arrowhead: lipid bilayer; white arrow: protrusions on the gut yellow granule.
Fig 7.
Analysis of the key genes involved in Paralvinella hessleri orpiment biomineralization.
A: Proteins identified in three P. hessleri yellow granules samples. B: Gene ontology cellular component classification (GO CC) of P. hessleri yellow granule proteome. C: Subcellular locations analysis of P. hessleri yellow granule proteome. D: Top 5 most abundantly expressed membrane proteins in the P. hessleri yellow granule proteome. E: Immuno-histochemistry analysis of the 001332F.4 Multidrug resistance-associated protein. F: Sequence alignment analysis of two P. hessleri intracellular hemoglobins. G: Fluorescent in situ hybridization analysis of gene encoding P. hessleri Intracellular hemoglobin 1 (iHem-1, 000092F.85) in the branchial apparatus. H: Fluorescent in situ hybridization analysis of gene encoding P. hessleri Intracellular hemoglobin 2 (iHem-2, 000481F.41) in the H’ branchial apparatus and H” body wall of the P. hessleri.
Fig 8.
The “Fighting poison with poison” arsenic detoxification in Paralvinella hessleri.
Fig 9.
δ34S% analysis of the four typical animals collected from hydrothermal vent chimneys.
The animals were aligned based on the habitat distance (habitat zones) from the hydrothermal venting. The Paralvinella hessleri which lives close to the hydrothermal venting is on the bottom while the Bathymodiolus platifrons which lives further away is at the top. The seawater and hydrothermal venting H2S δ34S% are based on Seal [81] and Gamo [42].