Abstract:The euryarchaeon Thermococcus prieurii inhabits deep-sea hydrothermal vents, one of the most extreme environments on Earth, which is reduced and enriched with heavy metals. Transmission electron microscopy and cryo-electron microscopy imaging of T. prieurii revealed the production of a plethora of diverse membrane vesicles (MVs) (from 50 nm to 400 nm), as is the case for other Thermococcales. T. prieurii also produces particularly long nanopods/nanotubes, some of them containing more than 35 vesicles encased i… Show more
“…Thus, the detached sheaths could potentially be formed solely by SlaA proteins, suggesting SlaA subunits to tightly bind to each other but not to the membrane, unless efficiently anchored by the help of SlaB. Detachment of the S-layer sheaths from the slaB-depleted cell envelope was increasingly apparent in cells that showed vesicle protrusions, where the budding vesicle appeared to "pull" the S-layer lattice off the cell wall, a phenomenon which has never been reported for wild-type cells 54,55 . We therefore suggest that a SlaB-depleted Slayer also affects vesicle secretion and coating, as those vesicle poles facing the cell did not seem to be properly covered with the S-layer (cf.…”
The S-layer is a proteinaceous surface lattice found in the cell envelope of bacteria and archaea. In most archaea, a glycosylated S-layer constitutes the sole cell wall and there is evidence that it contributes to cell shape maintenance and stress resilience. Here we use a gene-knockdown technology based on an endogenous CRISPR type III complex to gradually silence slaB, which encodes the S-layer membrane anchor in the hyperthermophilic archaeon Sulfolobus solfataricus. Silenced cells exhibit a reduced or peeled-off S-layer lattice, cell shape alterations and decreased surface glycosylation. These cells barely propagate but increase in diameter and DNA content, indicating impaired cell division; their phenotypes can be rescued through genetic complementation. Furthermore, S-layer depleted cells are less susceptible to infection with the virus SSV1. Our study highlights the usefulness of the CRISPR type III system for gene silencing in archaea, and supports that an intact S-layer is important for cell division and virus susceptibility.
“…Thus, the detached sheaths could potentially be formed solely by SlaA proteins, suggesting SlaA subunits to tightly bind to each other but not to the membrane, unless efficiently anchored by the help of SlaB. Detachment of the S-layer sheaths from the slaB-depleted cell envelope was increasingly apparent in cells that showed vesicle protrusions, where the budding vesicle appeared to "pull" the S-layer lattice off the cell wall, a phenomenon which has never been reported for wild-type cells 54,55 . We therefore suggest that a SlaB-depleted Slayer also affects vesicle secretion and coating, as those vesicle poles facing the cell did not seem to be properly covered with the S-layer (cf.…”
The S-layer is a proteinaceous surface lattice found in the cell envelope of bacteria and archaea. In most archaea, a glycosylated S-layer constitutes the sole cell wall and there is evidence that it contributes to cell shape maintenance and stress resilience. Here we use a gene-knockdown technology based on an endogenous CRISPR type III complex to gradually silence slaB, which encodes the S-layer membrane anchor in the hyperthermophilic archaeon Sulfolobus solfataricus. Silenced cells exhibit a reduced or peeled-off S-layer lattice, cell shape alterations and decreased surface glycosylation. These cells barely propagate but increase in diameter and DNA content, indicating impaired cell division; their phenotypes can be rescued through genetic complementation. Furthermore, S-layer depleted cells are less susceptible to infection with the virus SSV1. Our study highlights the usefulness of the CRISPR type III system for gene silencing in archaea, and supports that an intact S-layer is important for cell division and virus susceptibility.
“…Indeed, cultivated representatives of the hyperthermophilic Caldimicrobium relatives (Thermodesulfobacteria), Thermotogales, Desulfurococcales, and Archaeoglobales identified in hydrothermal sediments (Figure 4 and Table S5) have metabolic potentials mainly based on sulfur compounds utilization. Various lineages affiliated to Thermotogales and Desulfurococcales can use elemental sulfur and polysulfide as electron acceptor (Erauso et al, 1993;González et al, 1998;Adams et al, 2001;Huber and Stetter, 2006;Gorlas et al, 2015) whereas Caldimicrobium, identified in large proportion in the deepest sediment layers (Figure 4 and Table S5), can disproportionate elemental sulfur and generate sulfate and hydrogen sulfide as described for Caldimicrobium thiodismutans sp. nov (Kojima et al, 2016).…”
Section: Hydrothermal Influence Leads To Contrasted Microbial Communitymentioning
In the Guaymas Basin, the presence at a few tens of kilometers of cold seeps and hydrothermal vents coupled with comparable sedimentary settings and depths offer a unique opportunity to assess and compare the microbial community composition of these deep-sea ecosystems. The microbial diversity in sediments from three cold seep and two hydrothermal vent assemblages were investigated using high-throughput 16S rRNA-sequencing. Numerous bacterial and archaeal lineages were detected in both cold seep and hydrothermal vent sediments. Various potential organic matter degraders (e.g., Chloroflexi, Atribacteria, MBG-D) and methane and sulfur cycling related microorganisms (e.g., ANME and methanogenic lineages, sulfate-reducing lineages) were detected in both ecosystems. This suggests that analogous metabolic processes such as organic matter degradation and anaerobic methane oxidation coupled to sulfate reduction, were probably occurring in these two contrasted ecosystems. These highlighted "core microbiome" of the Guaymas Basin chemosynthetic ecosystems might therefore result from the combined presence of up-rising fluid emissions and high sedimentary rates of organic matter in the Basin. These results, coupled with the detailed ribotype analysis of major archaeal lineages (ANME-1, ANME-2, and MBG-D), also suggest a potential connectivity among deep-sea ecosystems of the Guaymas Basin likely due to the sedimentary context and the absence of physical border. However, thermophilic and hyperthermophilic lineages (e.g., Thermodesulfobacteria, Desulfurococcales, etc.) were exclusively identified in hydrothermally impacted sediments highlighting the strong influence of temperature gradients and other hydrothermally-related factors such as thermogenic sulfate reduction and sulfide formation on microbial community composition.
“…The large variation in size, morphology and density of these vesicles (by TEM) and blebs (by HIM) illustrates the degree of heterogeneity of these membrane structures. As such, they may contain a mixed population of exocytotic vesicles such as microparticles and exosomes, as well as yet unidentified nanopods or nanotubules that are only minimally studied in bacteria 33 , 34 . Figure 5 Bleb-like microprojections from podocytes in CD2AP deficient mice.…”
Helium ion scanning microscopy (HIM) is a novel technology that directly visualizes the cell surface ultrastructure without surface coating. Despite its very high resolution, it has not been applied extensively to study biological or pathology samples. Here we report the application of this powerful technology to examine the three-dimensional ultrastructural characteristics of proteinuric glomerulopathy in mice with CD2-associated protein (CD2AP) deficiency. HIM revealed the serial alteration of glomerular features including effacement and disorganization of the slit diaphragm, followed by foot process disappearance, flattening and fusion of major processes, and eventual transformation into a podocyte sheet as the disease progressed. The number and size of the filtration slit pores decreased. Strikingly, numerous “bleb” shaped microprojections were observed extending from podocyte processes and cell body, indicating significant membrane dynamics accompanying CD2AP deficiency. Visualizing the glomerular endothelium and podocyte-endothelium interface revealed the presence of endothelial damage, and disrupted podocyte and endothelial integrity in 6 week-old Cd2ap-KO mice. We used the HIM technology to investigate at nanometer scale resolution the ultrastructural alterations of the glomerular filtration apparatus in mice lacking the critical slit diaphragm-associated protein CD2AP, highlighting the great potential of HIM to provide new insights into the biology and (patho)physiology of glomerular diseases.
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