The ubiquitin‐proteasome system (UPS) is a rapid regulatory mechanism for selective protein degradation in plants and plays crucial roles in growth and development. There is increasing evidence that ...the UPS is also an integral part of plant adaptation to environmental stress, such as drought, salinity, cold, nutrient deprivation and pathogens. This review focuses on recent studies illustrating the important functions of the UPS components E2s, E3s and subunits of the proteasome and describes the regulation of proteasome activity during plant responses to environment stimuli. The future research hotspots and the potential for utilization of the UPS to improve plant tolerance to stress are discussed.
The ubiquitin‐proteasome system (UPS) plays crucial roles in plant responses to environment stimuli through degrading distinct target proteins. This review summaries recent progress in our understanding of the regulation of UPS components, subunits and proteasome activity under abiotic and biotic stress, and future research hotspots are discussed.
The family
, belonging to the order
, class
, is globally distributed in various environments. Currently, this family consist of seven genera:
,
,
,
,
,
and
. As more species are identified, the ...taxonomic status of the family
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
,
,
,
,
,
,
,
,
,
and
are proposed. We reclassified all species of
and
as species of
. This study is the first genomic-based study of the family
, and will contribute to further insights into the evolution of this family.
Advancement of DNA sequencing technology allows the routine use of genome sequences in the various fields of microbiology. The information held in genome sequences proved to provide objective and ...reliable means in the taxonomy of prokaryotes. Here, we describe the minimal standards for the quality of genome sequences and how they can be applied for taxonomic purposes.
Controlling the chemical environments of the active metal atom including both coordination number (CN) and local composition (LC) is vital to achieve active and stable single-atom catalysts (SACs), ...but remains challenging. Here we synthesized a series of supported Pt1 SACs by depositing Pt atoms onto the pretuned anchoring sites on nitrogen-doped carbon using atomic layer deposition. In hydrogenation of para-chloronitrobenzene, the Pt1 SAC with a higher CN about four but less pyridinic nitrogen (Npyri) content exhibits a remarkably high activity along with superior recyclability compared to those with lower CNs and more Npyri. Theoretical calculations reveal that the four-coordinated Pt1 atoms with about 1 eV lower formation energy are more resistant to agglomerations than the three-coordinated ones. Composition-wise decrease of the Pt–Npyri bond upshifts gradually the Pt-5d center, and minimal one Pt–Npyri bond features a high-lying Pt-5d state that largely facilitates H2 dissociation, boosting hydrogenation activity remarkably.
Summary
Bacterial secondary metabolites are rich sources of novel drug leads. The diversity of secondary metabolite biosynthetic gene clusters (BGCs) in genome‐sequenced bacteria, which will provide ...crucial information for the efficient discovery of novel natural products, has not been systematically investigated. Here, the distribution and genetic diversity of BGCs in 10 121 prokaryotic genomes (across 68 phyla) were obtained from their PRISM4 outputs using a custom python script. A total of 18 043 BGCs are detected from 5743 genomes with non‐ribosomal peptide synthetases (25.4%) and polyketides (15.9%) as the dominant classes of BGCs. Bacterial strains harbouring the largest number of BGCs are revealed and BGC count in strains of some genera vary greatly, suggesting the necessity of individually evaluating the secondary metabolism potential. Additional analysis against 102 strains of discovered bacterial genera with abundant amounts of BGCs confirms that Kutzneria, Kibdelosporangium, Moorea, Saccharothrix, Cystobacter, Archangium, Actinosynnema, Kitasatospora, and Nocardia, may also be important sources of natural products and worthy of priority investigation. Comparative analysis of BGCs within these genera indicates the great diversity and novelty of the BGCs. This study presents an atlas of bacterial secondary metabolite BGCs that provides a lot of key information for the targeted discovery of novel natural products.
Increasing selectivity without the expense of activity is desired but challenging in heterogeneous catalysis. By revealing the molecule saturation and adsorption sensitivity on overlayer thickness, ...strain, and coordination of Pd‐based catalysts from first‐principles calculations, we designed a stable Pd monolayer (ML) catalyst on a Ru terrace to boost both activity and selectivity of acetylene semihydrogenation. The least saturated molecule is most sensitive to the change in catalyst electronic and geometric properties. By simultaneously compressing the Pd ML and exposing the high coordination sites, the adsorption of more saturated ethylene is considerably weakened to facilitate the desorption for high selectivity. The even stronger weakening to the least saturated acetylene drives its hydrogenation such that it is more exothermic, thereby boosting the activity. Tailoring the molecule saturation and its sensitivity to structure and composition provides a tool for rational design of efficient catalysts.
An effective catalyst for semihydrogenation of acetylene was created by layering Pd on large Ru nanoparticles with terrace sites and a smaller lattice constant. The catalyst stabilizes unsaturated acetylene as it undergoes semihydrogenation while promoting ethylene desorption, thereby achieving high activity and selectivity at the same time.
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 Escherichia coli and Mycobacterium Smegmatis. 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.
The efficient electrochemical hydrogen evolution reaction (HER) plays a key role in accelerating sustainable H2 production from water electrolysis, but its large-scale applications are hindered by ...the high cost of the state-of-the-art Pt catalyst. In this work, submonolayer Pt was controllably deposited on an intermetallic Pd3Pb nanoplate (AL-Pt/Pd3Pb). The atomic efficiency and electronic structure of the active surface Pt layer were largely optimized, greatly enhancing the acidic HER. AL-Pt/Pd3Pb exhibits an outstanding HER activity with an overpotential of only 13.8 mV at 10 mA/cm2 and a high mass activity of 7834 A/gPd+Pt at −0.05 V, both largely surpassing those of commercial Pt/C (30 mV, 1486 A/gPt). In addition, AL-Pt/Pd3Pb shows excellent stability and robustness. Theoretical calculations show that the improved activity is mainly derived from the charge transfer from Pd3Pb to Pt, resulting in a strong electrostatic interaction that can stabilize the transition state and lower the barrier.
The changeable molecular dynamics of flexible polar cations in the variable confined space between inorganic chains brings about a new type of two‐step nonlinear optical (NLO) switch with genuine ...“off–on–off” second harmonic generation (SHG) conversion between one NLO‐active state and two NLO‐inactive states.
Two Gram-negative, non-spore-forming, non-motile, non-flagellated bacteria, designated strains D6
and DH64
, were isolated from surface water of the Pacific Ocean. For strain D6
, growth occurred at ...10-40 °C, pH 5.5-9.0 and in the presence of 0-8.0 % NaCl (w/v). For strain DH64
, growth occurred at 10-40 °C, pH 5.5-8.5 and in the presence of 0.5-8.0 % NaCl (w/v). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strains D6
and DH64
both belonged to the genera
, with the highest sequence identities to
JCM 17757
(98.2 %) and
JCM 11811
(98.6 %), respectively. The 16S rRNA gene sequence identity between strains D6
and DH64
was 95.9 %. The average amino acid identity and digital DNA-DNA hybridization values between the two strains and the nearest phylogenetic neighbours were 66.7-93.3 % and 16.1-38.5 %, respectively. The major respiratory quinone of both strains was menaquinone-6. The major polar lipid was phosphatidylethanolamine. The major fatty acids were identified similarly as iso-C
G, iso-C
and iso-C
3-OH. The genomic G+C contents of strains D6
and DH64
were determined to be 45.5 and 42.6 mol%, respectively. The combined genotypic and phenotypic data show that the strains represent two novel species within genera
, for which the names
sp. nov. and
sp. nov. are proposed, with type strains D6
(=MCCC M28982
=KCTC 92604
) and DH64
(=MCCC M28986
=KCTC 92975
).
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