Strigolactones (SLs) are a group of newly identified plant hormones that control plant shoot branching. SL signalling requires the hormone-dependent interaction of DWARF 14 (D14), a probable ...candidate SL receptor, with DWARF 3 (D3), an F-box component of the Skp-Cullin-F-box (SCF) E3 ubiquitin ligase complex. Here we report the characterization of a dominant SL-insensitive rice (Oryza sativa) mutant dwarf 53 (d53) and the cloning of D53, which encodes a substrate of the SCF(D3) ubiquitination complex and functions as a repressor of SL signalling. Treatments with GR24, a synthetic SL analogue, cause D53 degradation via the proteasome in a manner that requires D14 and the SCF(D3) ubiquitin ligase, whereas the dominant form of D53 is resistant to SL-mediated degradation. Moreover, D53 can interact with transcriptional co-repressors known as TOPLESS-RELATED PROTEINS. Our results suggest a model of SL signalling that involves SL-dependent degradation of the D53 repressor mediated by the D14-D3 complex.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The COVID-19 pandemic caused by nonstop infections of SARS-CoV-2 has continued to ravage many countries worldwide. Here we report that suramin, a 100-year-old drug, is a potent inhibitor of the ...SARS-CoV-2 RNA-dependent RNA polymerase (RdRp) and acts by blocking the binding of RNA to the enzyme. In biochemical assays, suramin and its derivatives are at least 20-fold more potent than remdesivir, the currently approved nucleotide drug for treatment of COVID-19. The 2.6 Å cryo-electron microscopy structure of the viral RdRp bound to suramin reveals two binding sites. One site directly blocks the binding of the RNA template strand and the other site clashes with the RNA primer strand near the RdRp catalytic site, thus inhibiting RdRp activity. Suramin blocks viral replication in Vero E6 cells, although the reasons underlying this effect are likely various. Our results provide a structural mechanism for a nonnucleotide inhibitor of the SARS-CoV-2 RdRp.
Abstract
Vasoactive intestinal polypeptide receptor (VIP1R) is a widely expressed class B G protein-coupled receptor and a drug target for the treatment of neuronal, metabolic, and inflammatory ...diseases. However, our understanding of its mechanism of action and the potential of drug discovery targeting this receptor is limited by the lack of structural information of VIP1R. Here we report a cryo-electron microscopy structure of human VIP1R bound to PACAP27 and Gs heterotrimer, whose complex assembly is stabilized by a NanoBiT tethering strategy. Comparison with other class B GPCR structures reveals that PACAP27 engages VIP1R with its N-terminus inserting into the ligand binding pocket at the transmembrane bundle of the receptor, which subsequently couples to the G protein in a receptor-specific manner. This structure has provided insights into the molecular basis of PACAP27 binding and VIP receptor activation. The methodology of the NanoBiT tethering may help to provide structural information of unstable complexes.
Abstract
Vera C. Rubin Observatory is a ground-based astronomical facility under construction, a joint project of the National Science Foundation and the U.S. Department of Energy, designed to ...conduct a multipurpose 10 yr optical survey of the Southern Hemisphere sky: the Legacy Survey of Space and Time. Significant flexibility in survey strategy remains within the constraints imposed by the core science goals of probing dark energy and dark matter, cataloging the solar system, exploring the transient optical sky, and mapping the Milky Way. The survey’s massive data throughput will be transformational for many other astrophysics domains and Rubin’s data access policy sets the stage for a huge community of potential users. To ensure that the survey science potential is maximized while serving as broad a community as possible, Rubin Observatory has involved the scientific community at large in the process of setting and refining the details of the observing strategy. The motivation, history, and decision-making process of this strategy optimization are detailed in this paper, giving context to the science-driven proposals and recommendations for the survey strategy included in this Focus Issue.
To date there is virtually no information available concerning the fungi associated with
Tectona grandis
(teak) (
Lamiaceae
) in Thailand. In this study, samples of microfungi were collected from ...both asymptomatic stems and dead wood, and symptomatic branches, stem and leaves of
T. grandis
from 27 sites in six provinces (Chiang Mai, Chiang Rai, Phayao, Phitsanulok, Phrae and Uttaradit Provinces). Morphology and combined multi-gene phylogeny (CAL, GAPDH, ITS, LSU, RPB2, SSU, TEF1 and TUB) were used to identify taxa. A total of 270 collections, representing 28 fungal species residing in 12 families, 7 orders and 21 genera, with three species of uncertain taxonomic placement were identified. Of these, one family, three genera and 14 species are new to science. The new family,
Pseudocoleodictyosporaceae
is introduced based on its distinct lineage in the Dothideomycetes and its unique morphology as compared to
Roussoellaceae
and
Torulaceae
. The new genera are
Neooccultibambusa
,
Pseudocoleodictyospora
and
Subglobosporium
. The newly described species are
Diaporthe neoraonikayaporum
,
D. tectonendophytica
,
D. tectonae
,
D. tectonigena
,
Hermatomyces tectonae
,
H. thailandica
,
Manoharachariella tectonae
,
Neooccultibambusa chiangraiensis
,
Pseudocoleodictyospora sukhothaiensis
,
Ps. tectonae
,
Ps. thailandica
,
Rhytidhysteron tectonae
,
Subglobosporium tectonae
and
Tubeufia tectonae
. Fourteen species are known published taxa including
Alternaria tillandsiae
,
Berkleasmium talaumae
,
Boerlagiomyces macrospora
,
Ceratocladium purpureogriseum
,
Fusarium solani
,
Helicoma siamense
,
Lasiodiplodia theobromae
,
Macrovalsaria megalospora
,
Paradictyoarthrinium diffractum
,
Phaeoacremonium italicum
,
Sphaeropsis eucalypticola
,
Stachybotrys levispora
,
St. renispora
and
Thaxteriellopsis lignicola
. Epitypifications or reference specimens are designated for
Boerlagiomyces macrospora
and
Macrovalsaria megalospora. Macrovalsaria megalospora
is transferred from
Botryosphaeriaceae
to Dothideomycetes genus,
incertae sedis
based on taxonomy and phylogenetic analysis, which indicate it is distinct from
Botryosphaeriaceae
. All fungal species represent first reports on
T. grandis
in Thailand. New taxa and taxa
incertae sedis
, as well as known taxa which are established as reference specimens or epitypes, are presented with phylogenetic tree analyses, habitat, known distribution, material examined, full descriptions, notes and figures. Information is also provided for known taxa to add to the body of knowledge and to assist those wishing to study fungi occurring on
T. grandis
in future.
2D nanomaterials are emerging rapidly because of their exceptional chemical and physical properties. Reducing the thickness or number of crystalline layers improves the catalytic performance of many ...semiconductors, and thus, different exfoliation strategies have been proposed. However, many exfoliation methods can cause damage or chemical modifications, and control over size and aggregation can be problematic. Herein, In2S3 was grown in the surfactant-modified interlayer space of the layered silicate clay Laponite, leading to a hybrid nanostructure containing 1–1.5 nm thick lamellae of In2S3. The synthetic parameters varied the thickness and regularity of the In2S3 layers, and drastic changes in photophysical properties were observed, underlining the importance of colloidal interactions for templated growth. Photocurrent measurements and photocatalysis experiments showed that more than an order of magnitude increased apparent quantum efficiency and internal photon to current conversion efficiency over In2S3. This was attributed to fast interfacial charge transfer, enhanced redox capability, and improved charge transport properties of the In2S3 layers because of reduced layer thickness and isolation by magnesiosilicate nanoclay in between. Overall, this study provides a simple colloidal approach to grow defined layered heterostructures of In2S3 with limited thickness and enhanced photophysical properties, allowing improved catalysis. The photocatalytic enhancement, facile synthesis, and increased product yield compared with pure In2S3 make these promising materials for energy conversion and environmental remediation.
Abstract
Background
Knowledge on the epidemiological features and transmission patterns of novel coronavirus disease (COVID-19) is accumulating. Detailed line-list data with household settings can ...advance the understanding of COVID-19 transmission dynamics.
Methods
A unique database with detailed demographic characteristics, travel history, social relationships, and epidemiological timelines for 1407 transmission pairs that formed 643 transmission clusters in mainland China was reconstructed from 9120 COVID-19 confirmed cases reported during 15 January–29 February 2020. Statistical model fittings were used to identify the superspreading events and estimate serial interval distributions. Age- and sex-stratified hazards of infection were estimated for household vs nonhousehold transmissions.
Results
There were 34 primary cases identified as superspreaders, with 5 superspreading events occurred within households. Mean and standard deviation of serial intervals were estimated as 5.0 (95% credible interval CrI, 4.4–5.5) days and 5.2 (95% CrI, 4.9–5.7) days for household transmissions and 5.2 (95% CrI, 4.6–5.8) and 5.3 (95% CrI, 4.9–5.7) days for nonhousehold transmissions, respectively. The hazard of being infected outside of households is higher for people aged 18–64 years, whereas hazard of being infected within households is higher for young and old people.
Conclusions
Nonnegligible frequency of superspreading events, short serial intervals, and a higher risk of being infected outside of households for male people of working age indicate a significant barrier to the identification and management of COVID-19 cases, which requires enhanced nonpharmaceutical interventions to mitigate this pandemic.
A unique COVID-19 line-list database comprising 1407 transmission pairs that formed 643 clusters in mainland China outside Hubei province was reconstructed to estimate superspreading events, serial intervals, and hazard of infection for household vs nonhousehold settings.
Sordariomycetes
is one of the largest classes of
Ascomycota
and is characterised by perithecial ascomata and inoperculate unitunicate asci. The class includes many important plant pathogens, as well ...as endophytes, saprobes, epiphytes, and fungicolous, lichenized or lichenicolous taxa. The class includes freshwater, marine and terrestrial taxa and has a worldwide distribution. This paper provides an updated outline of the
Sordariomycetes
and a backbone tree incorporating asexual and sexual genera in the class. Based on phylogeny and morphology we introduced three subclasses;
Diaporthomycetidae, Lulworthiomycetidae
and
Meliolomycetidae
and five orders;
Amplistromatales
,
Annulatascales
,
Falcocladiales
,
Jobellisiales
and
Togniniales
. The outline is based on literature to the end of 2014 and the backbone tree published in this paper. Notes for 397 taxa with information, such as new family and genera novelties, novel molecular data published since the Outline of Ascomycota 2009, and new links between sexual and asexual genera and thus synonymies, are provided. The Sordariomycetes now comprises six subclasses, 28 orders, 90 families and 1344 genera. In addition a list of 829 genera with uncertain placement in
Sordariomycetes
is also provided.
Adhesion G-protein-coupled receptors (aGPCRs) are important for organogenesis, neurodevelopment, reproduction and other processes
. Many aGPCRs are activated by a conserved internal (tethered) ...agonist sequence known as the Stachel sequence
. Here, we report the cryogenic electron microscopy (cryo-EM) structures of two aGPCRs in complex with G
: GPR133 and GPR114. The structures indicate that the Stachel sequences of both receptors assume an α-helical-bulge-β-sheet structure and insert into a binding site formed by the transmembrane domain (TMD). A hydrophobic interaction motif (HIM) within the Stachel sequence mediates most of the intramolecular interactions with the TMD. Combined with the cryo-EM structures, biochemical characterization of the HIM motif provides insight into the cross-reactivity and selectivity of the Stachel sequences. Two interconnected mechanisms, the sensing of Stachel sequences by the conserved 'toggle switch' W
and the constitution of a hydrogen-bond network formed by Q
/Y
and the P
/V
φφG
motif (φ indicates a hydrophobic residue), are important in Stachel sequence-mediated receptor activation and G
coupling. Notably, this network stabilizes kink formation in TM helices 6 and 7 (TM6 and TM7, respectively). A common G
-binding interface is observed between the two aGPCRs, and GPR114 has an extended TM7 that forms unique interactions with G
. Our structures reveal the detailed mechanisms of aGPCR activation by Stachel sequences and their G
coupling.
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