Recent findings have revealed that the protein gasdermin D (GSDMD) plays key roles in cell pyroptosis. GSDMD binds lipids and forms pore structures to induce pyroptosis upon microbial infection and associated danger signals. However, detailed structural information for GSDMD remains unknown. Here, we report the crystal structure of the C-terminal domain of human GSDMD (GSDMD-C) at 2.64-Å resolution. The first loop on GSDMD-C inserts into the N-terminal domain (GSDMD-N), which helps stabilize the conformation of the full-length GSDMD. Substitution of this region by a short linker sequence increased levels of cell death. Mutants F283A and F283R can increase protein heterogeneity in vitro and are capable of undergoing cell pyroptosis in 293T cells. The small-angle X-ray-scattering envelope of human GSDMD is consistent with the modeled GSDMD structure and mouse GSDMA3 structure, which suggests that GSDMD adopts an autoinhibited conformation in solution. The positive potential surface of GSDMD-N covered by GSDMD-C is exposed after being released from the autoinhibition state and can form high-order oligomers via a charge-charge interaction. Furthermore, by mapping different regions of GSDMD, we determined that one short segment is sufficient to kill bacteria in vitro and can efficiently inhibit cell growth in and These findings reveal that GSDMD-C acts as an auto-inhibition executor and GSDMD-N could form pore structures via a charge-charge interaction upon cleavage by caspases during cell pyroptosis.
Recently, much attention has been attracted to the use of biomass to produce functional carbonaceous materials from the viewpoint of economic, environmental and societal issues. Among different techniques, the hydrothermal carbonization (HTC) process, a traditional but recently revived method, presents superior characteristics that make it a promising route of wide potential application. This perspective gives an overview of the latest advances in the HTC process of functional carbonaceous materials from biomass. First, we discuss the preparation of carbonaceous materials synthesized by the use of either highly directed or catalyst/template-assisted methods, from crude plant materials and carbohydrates respectively. These carbonaceous materials not only have special morphologies, such as nanospheres, nanocables, nanofibers, submicrocables, submicrotubes and porous structures, but also contain rich functional groups which can greatly improve hydrophilicity and chemical reactivity. Further, a general look is cast on the applications of this kind of carbonaceous materials in environmental, catalytic and electrical areas. Recent advances have demonstrated that the HTC process from biomass can provide promising methods for the rational design of a rich family of carbonaceous and hybrid functional carbon materials with important applications.
The family Erythrobacteraceae , belonging to the order Sphingomonadales , class Alphaproteobacteria , is globally distributed in various environments. Currently, this family consist of seven genera: Altererythrobacter , Croceibacterium , Croceicoccus , Erythrobacter , Erythromicrobium , Porphyrobacter and Qipengyuania . As more species are identified, the taxonomic status of the family Erythrobacteraceae should be revised at the genomic level because of its polyphyletic nature evident from 16S rRNA gene sequence analysis. Phylogenomic reconstruction based on 288 single-copy orthologous clusters led to the identification of three separate clades. Pairwise comparisons of average nucleotide identity, average amino acid identity (AAI), percentage of conserved protein and evolutionary distance indicated that AAI and evolutionary distance had the highest correlation. Thresholds for genera boundaries were proposed as 70 % and 0.4 for AAI and evolutionary distance, respectively. Based on the phylo-genomic and genomic similarity analysis, the three clades were classified into 16 genera, including 11 novel ones, for which the names Alteraurantiacibacter, Altericroceibacterium, Alteriqipengyuania, Alteripontixanthobacter, Aurantiacibacter, Paraurantiacibacter, Parerythrobacter, Parapontixanthobacter, Pelagerythrobacter, Tsuneonella and Pontixanthobacter are proposed. We reclassified all species of Erythromicrobium and Porphyrobacter as species of Erythrobacter . This study is the first genomic-based study of the family Erythrobacteraceae , and will contribute to further insights into the evolution of this family.
Resorcinol-formaldehyde (RF) and graphene oxide (GO) aerogels have found a variety of applications owing to their excellent properties and remarkable flexibility. However, the macroscopic and controllable synthesis of their composite gels is still a great challenge. By using GO sheets as template skeletons and metal ions (Co(2+), Ni(2+), or Ca(2+)) as catalysts and linkers, the first low-temperature scalable strategy for the synthesis of a new kind of RF-GO composite gel with tunable densities and mechanical properties was developed. The aerogels can tolerate a strain as high as 80% and quickly recover their original morphology after the compression has been released. Owing to their high compressibility, the gels might find applications in various areas, for example, as adsorbents for the removal of dye pollutants and in oil-spill cleanup.
A novel fluorescence resonance energy transfer (FRET) system has been designed for the Cu2+ ions detection with optical visual assays. In this FRET reaction, the biocompatible, green luminescent monodisperse phenol formaldehyde resin nanoparticles (PFR NPs) synthesized by a simple hydrothermal method were used as the acceptor and the luminescent CdTe quantum dots (QDs) were selected as the donor. By the layer-by-layer method, the polyelectrolyte (PEI/PSS/PEI) were absorbed alternately on the surface of the PFR NPs. As a result, the amino groups were stably modified onto the surface of the PFR NPs. In the presence of 1-ethyl-3-(3-dimethly aminopropyl) carbodiimide (EDAC) and N-hydroxysuccinimide (NHS), the carboxyl groups coated CdTe QDs prepared by using mereaptoactetic acid (MA) as the stabilizer in water solution were coupled to the surface of amino group functionalized PFR NPs to obtain novel FRET nanocomposites. Owing to the sensitive quenching effect of Cu2+ ions on CdTe QDs and effective energy transfer from CdTe QDs to PFR NPs, the as-prepared FRET nanocomposites were utilized to monitor Cu2+ ion with optical visual detection at room temperature within 1 min. This nanoparticle-based FRET probe should promote further development of other nanocomposites for Cu2+ ion detection in the environmental field.
Three strains of Gram-negative, aerobic, neutrophilic and halophilic bacteria were isolated from samples of a salt lake on the Qinghai-Tibet Plateau and a subterranean saline well in the Si-Chuan Basin of China. These isolates, designated AJ275 T , AJ282 T and ZG16 T , were investigated using a polyphasic approach. Based on 16S rRNA gene sequence analysis, the isolates could be affiliated to the genus Halomonas. Genomic DNA G+C contents were 65.9 mol% for AJ275 T , 56.7 mol% for AJ282 T and 57.6 mol% for ZG16 T . The results of DNA-DNA hybridizations, fatty acid analysis and physiological and biochemical tests allowed the isolates to be differentiated genotypically and phenotypically from closely related species. It is proposed that strains AJ275 T (=CGMCC 1.6493 T =JCM 14606 T =LMG 23976 T ), AJ282 T (=CGMCC 1.6494 T =JCM 14607 T =LMG 23978 T ) and ZG16 T (=CGMCC 1.6495 T =JCM 14608 T =LMG 23977 T ) represent the type strains of three novel species in the genus Halomonas: Halomonas saccharevitans sp. nov., Halomonas arcis sp. nov. and Halomonas subterranea sp. nov., respectively.
Two halophilic archaeal strains TBN4(T) and TBN5 were isolated from Taibei marine solar saltern in Jiangsu, China. Both strains showed light red-pigmented colonies and their cells were rod, motile and Gram-stain-negative. They were able to grow at 25-50°C (optimum 37°C), at 1.4-4.3 M NaCl (optimum 2.1 M NaCl), at 0-1.0 M MgCl(2) (optimum 0.005 M MgCl(2)) and at pH 6.0-9.0 (optimum pH 7.0). Their cells lyse in distilled water and minimal NaCl concentration to prevent cell lysis is 8% (w/v). The major polar lipids of the two strains were PG (phosphatidylglycerol), PGP-Me (phosphatidylglycerol phosphate methyl ester), PGS (phosphatidylglycerol sulfate) and five glycolipids chromatographically identical to S-TGD-1 (sulfated galactosyl mannosyl glucosyl diether), S-DGD-1 (sulfated mannosyl glucosyl diether), TGD-1 (galactosyl mannosyl glucosyl diether), DGD-1 (mannosyl glucosyl diether) and DGD-2 (an unknown diglycosyl diether). Phylogenetic analysis revealed that TBN4(T) and strain TBN5 formed a distinct clade with genus Haladaptatus (showing 90.0-90.9% 16S rRNA gene similarities). The DNA G + C content of strain TBN4(T) and strain TBN5 are 66.1 and 65.4 mol%, respectively. The DNA-DNA hybridization value between strain TBN4(T) and strain TBN5 was 94.3%. The phenotypic, chemotaxonomic and phylogenetic properties suggest that strain TBN4(T) and strain TBN5 represent a novel species in a new genus within the family Halobacteriaceae, for which the name Halorussus rarus gen. nov., sp. nov. is proposed. The type strain is TBN4(T) (=CGMCC 1.10122(T) = JCM 16429(T)).
Croceicoccus marinus gen. nov., sp. nov., a yellow-pigmented bacterium from deep-sea sediment, and emended description of the family Erythrobacteraceae A Gram-negative, aerobic, neutrophilic, coccoid bacterium, strain E4A9 T , was isolated from a deep-sea sediment sample collected from the East Pacific polymetallic nodule region. 16S rRNA gene sequence analysis showed that the isolate was related to the type strain of Altererythrobacter epoxidivorans (96.0 % sequence similarity). Lower 16S rRNA gene sequence similarities were observed with other members of the genera Altererythrobacter (94.7 %), Erythrobacter (94.0-95.4 %), Erythromicrobium (94.8 %) and Porphyrobacter (94.6-95.1 %) of the family Erythrobacteraceae. Phylogenetic analysis including all described species of the family Erythrobacteraceae and several members of the family Sphingomonadaceae revealed that the isolate formed a distinct phylogenetic lineage with the family Erythrobacteraceae. Chemotaxonomic analysis revealed ubiquinone-10 as the predominant respiratory quinone, anteiso-C 15 : 0 , iso-C 14 : 0 and iso-C 15 : 0 as major fatty acids, and phosphatidylglycerol as the major polar lipid. The DNA G+C content was 71.5 mol%. The isolate contained carotenoids, but no bacteriochlorophyll a. On the basis of phenotypic and genotypic data presented in this study, strain E4A9 T represents a novel species in a new genus in the family Erythrobacteraceae for which the name Croceicoccus marinus gen. nov., sp. nov. is proposed; the type strain is E4A9 T (5CGMCC 1.6776 T 5JCM 14846 T ).The family Erythrobacteraceae (order Sphingomonadales, class Alphaproteobacteria) was proposed by Lee et al. (2005) based on a comprehensive phylogenetic analysis and, at present, it comprises four recognized genera: Altererythrobacter (Kwon et al., 2007), Erythrobacter (Shiba & Simidu, 1982), Erythromicrobium (Yurkov et al., 1994) and Porphyrobacter (Fuerst et al., 1993).Members of the family Erythrobacteraceae are aerobic and produce pink, orange or yellow pigments. Ubiquinone-10 is the major respiratory quinone. Most species in the family have been isolated from various aquatic environments such as freshwater, seawater, marine mats or sediment, a hot spring, seaweed, a starfish and coral (Shiba & Simidu, 1982; Fuerst et al., 1993;Yurkov et al., 1994; Hanada et al., 1997; Denner et al., 2002; Hiraishi et al., 2002;Rainey et al., 2003;Yoon et al., 2003Yoon et al., , 2004a Yoon et al., , b, 2005a Yoon et al., , b, 2006Ivanova et al., 2005;Kwon et al., 2007). This study focuses on the description of strain E4A9 T , isolated from a deep-sea sediment sample. Based on the taxonomic data, it is proposed that this strain be included in a new genus within the family Erythrobacteraceae.The deep-sea sediment samples were collected by a multicorer from the East Pacific polymetallic nodule region (8 u 229 380 N 145 u 239 560 W) at a depth of Abbreviation: BChl a, bacteriochlorophyll a.The GenBank/EMBL/DDBJ accession number for the 16S rRNA gene sequence of strain E4A9 T is EF62399...
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