Over the past few years, three photorespiratory bypasses have been introduced into plants, two of which led to observable increases in photosynthesis and biomass yield. However, most of the ...experiments were carried out using Arabidopsis under controlled environmental conditions, and the increases were only observed under low-light and short-day conditions. In this study, we designed a new photorespiratory bypass (called GOC bypass), characterized by no reducing equivalents being produced during a complete oxidation of glycolate into CO2 catalyzed by three rice-self-originating enzymes, i.e., glycolate oxidase, oxalate oxidase, and catalase. We successfully established this bypass in rice chloroplasts using a multi-gene assembly and transformation system. Transgenic rice plants carrying GOC bypass (GOC plants) showed significant increases in photosynthesis efficiency, biomass yield, and nitrogen content, as well as several other CO2-enriched phenotypes under both greenhouse and field conditions. Grain yield of GOC plants varied depending on seeding season and was increased significantly in the spring. We further demonstrated that GOC plants had significant advantages under high-light conditions and that the improvements in GOC plants resulted primarily from a photosynthetic CO2-concentrating effect rather than from improved energy balance. Taken together, our results reveal that engineering a newly designed chloroplastic photorespiratory bypass could increase photosynthetic efficiency and yield of rice plants grown in field conditions, particularly under high light.
A new photorespiratory bypass (GOC bypass), catalyzed by three rice-self-originating enzymes, i.e., glycolate oxidase, oxalate oxidase, and catalase, was designed and successfully established in rice chloroplasts. Transgenic plants carrying GOC bypass showed increased photosynthetic efficiency and productivity in rice under field conditions, with particular advantages under high light, which were found to be resulted from a photosynthetic CO2-concentrating effect.
Neuronal intranuclear inclusion disease (NIID) is a slowly progressing neurodegenerative disease characterized by eosinophilic intranuclear inclusions in the nervous system and multiple visceral ...organs. The clinical manifestation of NIID varies widely, and both familial and sporadic cases have been reported. Here we have performed genetic linkage analysis and mapped the disease locus to 1p13.3-q23.1; however, whole-exome sequencing revealed no potential disease-causing mutations. We then performed long-read genome sequencing and identified a large GGC repeat expansion within human-specific NOTCH2NLC. Expanded GGC repeats as the cause of NIID was further confirmed in an additional three NIID-affected families as well as five sporadic NIID-affected case subjects. Moreover, given the clinical heterogeneity of NIID, we examined the size of the GGC repeat among 456 families with a variety of neurological conditions with the known pathogenic genes excluded. Surprisingly, GGC repeat expansion was observed in two Alzheimer disease (AD)-affected families and three parkinsonism-affected families, implicating that the GGC repeat expansions in NOTCH2NLC could also contribute to the pathogenesis of both AD and PD. Therefore, we suggest defining a term NIID-related disorders (NIIDRD), which will include NIID and other related neurodegenerative diseases caused by the expanded GGC repeat within human-specific NOTCH2NLC.
Rapid and dynamic change in hydrogen peroxide （H2O2） levels can serve as an important signal to regulate various biological processes in plants. The change is realized by tilting the balance between ...its production and scavenging rates, in which membrane-associated NADPH oxidases are known to play a crucial role. Functioning independently from NADPH oxidases, glycolate oxidase （GLO） was recently demonstrated as an aitemative source for H2O2 production during both germ-for-germ and non-host resistance in plants. In this study, we show that GLO physically interacts with catalase （CAT） in rice leaves, and that the interaction can be deregulated by salicylic acid （SA）. Furthermore, the GLO-mediated H2O2 accumulation is synergistically enhanced by SA. Based on the well-known mechanism of substrate channeling in enzyme complexes, SA-induced H2O2 accumulation likely results from SA-induced GLO-CAT dissociation. In the GLO-CAT complex, GLO-mediated H2O2 production during photorespiration is very high, whereas the affinity of CAT for H2O2 （measured Km ≈ 43 raM） is extraordinarily low. This unique combination can further potentiate the increase in H2O2 when GLO is dissociated from CAT. Taken together, we propose that the physical association-dissociation of GLO and CAT, in response to environmental stress or stimuli, seems to serve as a specific mechanism to modulate H2O2 levels in rice.
An advance Li‐sphere possessing a definitely regular morphology in Li deposition enables a well‐defined more robust structure and superior solid‐electrolyte interphase (SEI) to achieve ...high‐efficiency long‐term cycles in Li metal anode. Here, a new sight of high Li+ cluster‐like solvation sheaths coordinated in a localized high‐concentration NO3− (LH‐LiNO3) electrolyte fully clarifies for depositing advanced Li spheres. Moreover, we elucidate a critical amorphous‐crystalline phase transition in the nanostructure evolution of Li‐sphere deposits during the nucleation and growth. Li‐sphere anode exhibits ultra‐stable structural engineering for suppressing Li dendrite growths and rendering ultralong life of 4000 cycles in symmetrical cells at 2 mA cm−2. The as‐constructed Li spheres/3DCM|LiFePO4 (LFP) full cell delivers a high capacity retention of 90.5% at 1 C after 1000 cycles, and a robust dendrite‐free structure also stably exists in Li‐sphere anode. Combined with high‐loading LFP cathodes (6.6 and 10.9 mg cm−2), superb capacity retentions are up to 96.5% and 92.5% after 800 cycles at 1 C, respectively. Cluster‐like solvation sheaths with high Li+ coordination exert significant influence on depositing a high‐quality Li‐sphere anode.
High Li+ solvation sheaths coordinated in a localized high‐concentration NO3− enable advanced Li‐sphere growths and achieve a high‐quality long‐term cycle in promising Li‐metal batteries.
Methylation and demethylation of DNA are the complementary processes of epigenetic regulation. These two types of regulation influence a diverse array of cellular activities, including the ...maintenance of pluripotency and self-renewal in embryonic stem cells. It was generally believed that DNA demethylation occurs passively over several cycles of DNA replication and that active DNA demethylation is rare. Recently, evidence for active DNA demethylation has been obtained in several cancer, neuronal, and embryonic stem cell lines. Studies in embryonic stem cell models, however, suggested that active DNA demethylation might be restricted to the early development of progenitor cells. Whether active demethylation is involved in terminal differentiation of adult stem cells is poorly understood. We provide evidence that active DNA demethylation does occur during terminal specification of stem cells in an adipose-derived mesenchymal stem cell-derived osteogenic differentiation model. The medium CpG regions in promoters of the Dlx5, Runx2, Bglap, and Osterix osteogenic lineage-specific genes were demethylated during the increase in gene expression associated with osteogenic differentiation. The growth arrest and DNA damage-inducible protein GADD45A was up-regulated in these processes. Knockdown of GADD45A led to hypermethylation of Dlx5, Runx2, Bglap, and Osterix promoters, followed by suppression of the expression of these genes and interruption of osteogenic differentiation. These results reveal that GADD45A plays an essential role in gene-specific active DNA demethylation during adult stem cell differentiation. They enhance the current knowledge of osteogenic specification and may also lead to a better understanding of the common mechanisms underlying epigenetic regulation in adult stem cell differentiation.
To systematically investigate the genetic polymorphisms of the CYP3A4 gene in a Han Chinese population.
The promoter and exons of CYP3A4 gene in 1114 unrelated, healthy Han Chinese subjects were ...amplified and genotyped by direct sequencing.
In total, five previously reported alleles (*1G, *4, *5, *18B and *23) were detected, of which one allele (*23) was reported for the first time in Han Chinese population. Additionally, seven novel exonic variants were also identified and designated as new alleles CYP3A4*28-*34.
This study provides the most comprehensive data of CYP3A4 polymorphisms in Han Chinese population and detects the largest number of novel CYP3A4 alleles in one ethnic group.
Glycolate oxidase (GLO) is a key enzyme for photorespiration in plants. Previous studies have demonstrated that suppression of GLO causes photosynthetic inhibition, and the accumulated glycolate with ...the deactivated Rubisco is likely involved in the regulation. Using isolated Rubisco and chloroplasts, it has been found that only glyoxylate can effectively inactivate Rubisco and meanwhile inhibit photosynthesis, but little in vivo evidence has been acquired and reported. In this study, we have generated the transgenic rice (Oryza sativa) plants with GLO being constitutively silenced, and conducted the physiological and biochemical analyses on these plants to explore the regulatory mechanism. When GLO was downregulated, the net photosynthetic rate (Pn) was reduced and the plant growth was correspondingly stunted. Surprisingly, glyoxylate, as a product of the GLO catalysis, was accumulated in response to the GLO suppression, like its substrate glycolate. Furthermore, the glyoxylate content was found to be inversely proportional to the Pn while the Pn is directly proportional to the Rubisco activation state in the GLO‐suppressed plants. A mathematical fitting equation using least square method also demonstrated that the Rubisco activation state was inversely proportional to the glyoxylate content. Despite that the further analyses we have conducted failed to reveal how glyoxylate was accumulated in response to the GLO suppression, the current results do strongly suggest that there may exist an unidentified, alternative pathway to produce glyoxylate, and that the accumulated glyoxylate inhibits photosynthesis by deactivating Rubisco, and causes the photorespiratory phenotype in the GLO‐suppressed rice plants.
Lin28 inhibits the expression of let-7 microRNAs but also exhibits let-7-independent functions. Using immunoprecipitation and deep sequencing, we show here that Lin28 preferentially associates with a ...small subset of cellular mRNAs. Of particular interest are those for ribosomal proteins and metabolic enzymes, the expression levels of which are known to be coupled to cell growth and survival. Polysome profiling and reporter analyses suggest that Lin28 stimulates the translation of many or most of these targets. Moreover, Lin28-responsive elements were found within the coding regions of all target genes tested. Finally, a mutant Lin28 that still binds RNA but fails to interact with RNA helicase A (RHA), acts as a dominant-negative inhibitor of Lin28-dependent stimulation of translation. We suggest that Lin28, working in concert with RHA, enhances the translation of genes important for the growth and survival of human embryonic stem cells.
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