The cover picture shows key players in the catalytic cycle of the mammalian antioxidant enzyme, glutathione peroxidase (GPx). Selenocysteine selenenic acids (queen) and selenocysteine selenenyl ...sulfides (rook) are established contributors to GPx function. This study unveils a previously overlooked class of intermediates: selenocysteine cyclic selenenyl amides (king). Through model studies, their reactivity has been revealed, exhibiting dual functionality. They not only prevent the inactivation of GPx but also act as highly electrophilic intermediates in selenoprotein reactions. Their roles mirror a chess king, dynamically adapting to their application. More information can be found in the Research Article by K. Goto et al. (DOI: 10.1002/chem.202302615).
Ants are one of the most ecologically and numerically dominant group of terrestrial organisms with most species diversity currently found in tropical climates. Several explanations for the disparity ...of biological diversity in the tropics compared to temperate regions have been proposed including that the tropics may act as a "museum" where older lineages persist through evolutionary time or as a "cradle" where new species continue to be generated. We infer the molecular phylogenetic relationships of 295 ant specimens including members of all 21 extant subfamilies to explore the evolutionary diversification and biogeography of the ants. By constraining the topology and age of the root node while using 45 fossils as minimum constraints, we converge on an age of 139–158 Mya for the modern ants. Further diversification analyses identified 10 periods with a significant change in the tempo of diversification of the ants, although these shifts did not appear to correspond to ancestral biogeographic range shifts. Likelihood-based historical biogeographic reconstructions suggest that the Neotropics were important in early ant diversification (e.g., Cretaceous). This finding coupled with the extremely high-current species diversity suggests that the Neotropics have acted as both a museum and cradle for ant diversity.
The Western Ghats (WG) mountain chain is a global biodiversity hotspot with high diversity and endemicity of woody plants. The latitudinal breadth of the WG offers an opportunity to determine the ...evolutionary drivers of latitudinal diversity patterns. We examined the spatial patterns of evolutionary diversity using complementary phylogenetic diversity and endemism measures. To examine if different regions of the WG serve as a museum or cradle of evolutionary diversity, we examined the distribution of 470 species based on distribution modelling and occurrence locations across the entire region. In accordance with the expectation, we found that the southern WG is both a museum and cradle of woody plant evolutionary diversity, as a higher proportion of both old and young evolutionary lineages are restricted to the southern WG. The diversity gradient is likely driven by high geo-climatic stability in the south and phylogenetic niche conservatism for moist and aseasonal sites. This is corroborated by persistent lineage nestedness at almost all evolutionary depths (10-135 million years), and a strong correlation of evolutionary diversity with drought seasonality, precipitation and topographic heterogeneity. Our results highlight the global value of the WG, demonstrating, in particular, the importance of protecting the southern WG-an engine of plant diversification and persistence.
Selenocysteine (Sec)‐derived cyclic selenenyl amides, formed by the intramolecular cyclization of Sec selenenic acids (Sec–SeOHs), have been postulated to function as protective forms in the bypass ...mechanism of glutathione peroxidase (GPx). However, their chemical properties have not been experimentally elucidated in proteins or small‐molecule systems. Recently, we reported the first nuclear magnetic resonance observation of Sec–SeOHs and their cyclization to the corresponding cyclic selenenyl amides by using selenopeptide model systems incorporated in a molecular cradle. Herein, we elucidate the structures and reactivities of Sec‐derived cyclic selenenyl amides. The crystal structures and reactions toward a cysteine thiol or a 1,3‐diketone‐type chemical probe indicated the highly electrophilic character of cyclic selenenyl amides. This suggests that they can serve not only as protective forms to suppress the inactivation of Sec–SeOHs in GPx but also as highly electrophilic intermediates in the reactions of selenoproteins.
The crystal structures and reactivities of selenocysteine‐derived cyclic selenenyl amides have been elucidated. The results obtained here suggest that they can serve not only as protective forms to suppress the degradation of the active center in glutathione peroxidase but also as highly electrophilic intermediates in the several reactions of selenoproteins.
Abstract
Plant leaves are utilized by various shelter-building insects. Some insects are constrained in their host plant use by the difficulty in modifying leaves into shelters, while others may cope ...through different construction methods. Here, we show that the leaf-rolling weevil Phymatapoderus pavens (Coleoptera, Attelabidae) constructs two types of leaf rolⅼ on Boehmeria silvestrii (Urticaceae) according to the shape of the leaf. Female weevils make leaf rolls using the whole leaf when the leaf is small and weakly lobed, whereas they use only one of the lateral lobes when the leaf is large and deeply lobed. Both types were found within a population and each functioned as a site for the growth of offspring. Weevils bite the leaf veins differently when constructing each of these leaf rolls, suggesting that the leaf roll type is determined before the leaf is rolled. Compared with another leaf-rolling weevil species, Apoderus praecellens (Coleoptera, Attelabidae), which makes leaf rolls on similarly lobed leaves of Isodon umbrosus var. hakusanensis (Lamiaceae), P. pavens utilizes a wider range of leaf shapes because these weevils are able to construct leaf rolls on the lateral lobes of the leaves. Differences in leaf-rolling behaviour, leaf venation pattern, and the relative size of weevils and leaves are factors affecting the results.
Selenocysteine selenenic acids (Sec-SeOHs) and selenocysteine selenenyl iodides (Sec-SeIs) have long been recognized as crucial intermediates in the catalytic cycle of glutathione peroxidase (GPx) ...and iodothyronine deiodinase (Dio), respectively. However, the observation of these reactive species remained elusive until our recent study, where we successfully stabilized Sec-SeOHs and Sec-SeIs using a protective molecular cradle. Here, we report the first demonstration of the chemical transformation from a Sec-SeI to a Sec-SeOH through alkaline hydrolysis. A stable Sec-SeI derived from a selenocysteine methyl ester was synthesized using the protective cradle, and its structure was determined by crystallographic analysis. The alkaline hydrolysis of the Sec-SeI at -50 °C yielded the corresponding Sec-SeOH in an 89% NMR yield, the formation of which was further confirmed by its reaction with dimedone. The facile and nearly quantitative conversion of the Sec-SeI to the Sec-SeOH not only validates the potential involvement of this process in the catalytic mechanism of Dio, but also highlights its utility as a method for producing a Sec-SeOH.
The evolutionary dynamics underlying the latitudinal gradient in biodiversity have been controversial for over a century. Using a spatially explicit approach that incorporates not only origination ...and extinction but immigration, a global analysis of genera and subgenera of marine bivalves over the past 11 million years supports an "out of the tropics" model, in which taxa preferentially originate in the tropics and expand toward the poles without losing their tropical presence. The tropics are thus both a cradle and a museum of biodversity, contrary to the conceptual dichotomy dominant since 1974; a tropical diversity crisis would thus have profound evolutionary effects at all latitudes.
Germline stem cells continually produce sperm in vertebrate testes, whereas there is no direct evidence showing that germline stem cells are present in adult vertebrate ovaries. By using transgenic ...methods and clonal analysis, we identified germline stem cells that supported oogenesis and the production of offspring in the ovaries of adult medaka fish. Early-stage germ cells were localized in clusters along interwoven threadlike cords of sox9b-expressing somatic cells (termed germinal cradles) where the germ cells developed. Germline stem cells gave rise to germ cells that divided to produce cysts, which then underwent cell death or separated to form follicles. Our results provide insight into the germline stem cell biology of medaka and provide a model system for studying vertebrate stem cell niches.
Eriophyoid mites are among the most species‐rich superfamilies (Eriophyoidea) in the Acari, consisting of over 5000 named species. Although they exhibit a geographically uneven worldwide ...distribution, their regional spatiotemporal evolutionary patterns remain largely unknown. Here, we compiled a data set including 3058 occurrence records assigned into 1203 species in China. We found that eriophyoid mite species richness is higher in the southeast and lower in the northwest of China, coinciding with the 500‐mm annual precipitation isoline. Using fragments of two mitochondrial genes (COI, 12S rRNA) and two nuclear genes (18S rRNA, 28S rRNA) of 304 eriophyoid mite species, we constructed a regional dated phylogenetic tree in China. Our spatiotemporal analysis revealed that mountains in eastern and southern China had high eriophyoid mite species richness and phylogenetic clustering, possessing both ancient and young mite lineages. Species distribution modelling (SDM) results showed that the predicted suitable area of eriophyoid mites slightly expanded from the last inter‐glacial period to the last glacial maximum period. In comparison with the current SDM, a significantly larger distribution range was observed in future scenarios. These findings suggest that mountains in eastern and southern China acted as not only cradles—recent rapid speciation, but also museums—centre of gradual accumulation and preservation and provide insights into monitoring and conserving eriophyoid mites.
A small-molecule cysteine sulfenic acid (Cys-SOH) was synthesized and isolated as stable crystals, for the first time, by utilizing a nanosized molecular cavity as a protective cradle. The cradled ...Cys-SOH was synthesized by direct oxidation of the corresponding cysteine thiol with H
2
O
2
under basic conditions and its structure was established by X-ray crystallographic analysis. In the reaction of the cradled Cys-SOH with a thiol to produce the disulfide, a remarkable acceleration was observed upon the addition of an amine base. This suggests the important role of base in the reaction of Cys-SOH with thiols in biological systems. The cradled Cys-SOH was reduced to the cysteine thiol by dithiothreitol or triphenylphosphine. The high stability and sufficient reactivity of the cradled Cys-SOH indicate its usefulness as a small-molecule model compound for better understanding the chemical behavior of Cys-SOH in biological systems.
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