Low levels of growth hormone 20E in diapause‐destined pupae inhibit both PKA and sirtuin 2 levels, which fail to improve the c‐Myc/TFAM/cytochrome oxidase subunit IV (COXIV) expression and ...Glucose‐6‐phosphate dehydrogenase (G6PD) activity, and cause increased reactive oxygen species (ROS) levels in mitochondria and cytoplasm to induce diapause and extend the pupal lifespan. However, in nondiapause‐destined pupal brains, the activated PKA‐TFAM‐COXIV pathway and high G6PD activity respond to high 20E levels, which reduce the ROS levels and thus induce pupal‐adult development.
Previous studies have shown that high physiological levels of reactive oxygen species (ROS) in the brain promote pupal diapause, which extends the pupal lifespan. However, the molecular mechanisms of ROS generation are unclear. In this paper, we found that mitochondrial ROS (mtROS) levels in the brains of Helicoverpa armigera diapause‐destined pupae (DP) were higher and that the expression of cytochrome oxidase subunit IV (COXIV) was lower than in NP. In addition, downregulating COXIV caused mitochondrial dysfunction which elevated mtROS levels. Protein kinase A (PKA) was downregulated in DP, which led to the downregulated expression of the mitochondrial transcription factor TFAM. Low TFAM activity failed to promote COXIV expression and resulted in the high ROS levels that induced diapause. In addition, low sirtuin 2 expression suppressed glucose‐6‐phosphate dehydrogenase (G6PD) deacetylation at K382, which led to reduced G6PD activity and low NADPH levels, thereby maintaining high levels of ROS. Two proteins, COXIV and G6PD, thus play key roles in the elevated accumulation of ROS that induce diapause and extend the pupal lifespan.
Reactive oxygen species (ROS) are considered a major cause of ageing and ageing‐related diseases through protein carbonylation. Little is known about the molecular mechanisms that confer protection ...against ROS. Here, we observed that, compared with nondiapause‐destined pupae, high protein carbonyl levels are present in the brains of diapause‐destined pupae, which is a ‘non‐ageing’ phase in the moth Helicoverpa armigera. Protein carbonyl levels respond to ROS and decrease metabolic activity to induce diapause in order to extend lifespan. However, protein carbonylation in the brains of diapause‐destined pupae still occurs at a physiological level compared to young adult brains. We find that ROS activate Akt, and Akt then phosphorylates the transcription factor CREB to facilitate its nuclear import. CREB binds to the promoter of carbonyl reductase 1 (CBR1) and regulates its expression. High CBR1 levels reduce protein carbonyl levels to maintain physiological levels. This is the first report showing that the moth brain can naturally control protein carbonyl levels through a distinct ROS‐Akt‐CREB‐CBR1 pathway to extend lifespan.
High levels of ROS increase protein carbonyl levels to decrease enzyme activity and maintain a low metabolic activity to induce pupal diapause. Meanwhile, ROS activate Akt, which can phosphorylate CREB for nuclear import, and CREB then binds to the CBR1 promoter to regulate its expression. High levels of CBR1 reduce the protein carbonyl levels to maintain a physiological level of protein carbonyl to extend lifespan.
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.
Summary
Despite a much higher proportion of intragenic heterochromatin‐containing genes in crop genomes, the importance of intragenic heterochromatin in crop development remains unclear. Intragenic ...heterochromatin can be recognised by a protein complex, ASI1–AIPP1–EDM2 (AAE) complex, to regulate alternative polyadenylation.
Here, we investigated the impact of rice ASI1 on global poly(A) site usage through poly(A) sequencing and ASI1‐dependent regulation on rice development.
We found that OsASI1 is essential for rice pollen development and flowering. OsASI1 dysfunction has an important impact on global poly(A) site usage, which is closely related to heterochromatin marks. Intriguingly, OsASI1 interacts with the intronic heterochromatin of OsXRNL, a nuclear XRN family exonuclease gene involved in the processing of an miRNA precursor, to promote the processing of full‐length OsXRNL and regulate miRNA abundance. We found that OsASI1‐mediated regulation of pollen development partially depends on OsXRNL. Finally, we characterised the rice AAE complex and its involvement in alternative polyadenylation and pollen development.
Our findings help to elucidate an epigenetic mechanism governing miRNA abundance and rice development, and provide a valuable resource for studying the epigenetic mechanisms of many important processes in crops.
Gastric cancer (GC) is a common heterogeneous disease. The critical roles of microRNA‐340 (miR‐340) in the development and progression of GC were emphasized in accumulating studies. This study aims ...to examine the regulatory mechanism of miR‐340 in GC cellular processes. Initially, microarray technology was used to identify differentially expressed genes and regulatory miRs in GC. After that, the potential role of miR‐340 in GC was determined via ectopic expression, depletion, and reporter assay experiments. Expression of secreted phosphoprotein 1 (SPP1), miR‐340, phosphatidylinositol 3‐kinase/protein kinase B (PI3K/AKT) pathway, and epithelial–mesenchymal transition (EMT)‐related genes was measured. Moreover, to further explore the function of miR‐340 in vivo and in vitro, proliferation, apoptosis, migration, invasion, and tumorigenic capacity were evaluated. SPP1 was a target gene of miR‐340 which could then mediate the PI3K/AKT signaling pathway by targeting SPP1 in GC. Furthermore, miR‐340 levels were reduced and SPP1 was enriched in GC tissues and cells, with the PI3K/AKT signaling pathway being activated. Inhibitory effects of upregulated miR‐340 on SPP1 and the PI3K/AKT signaling pathway were confirmed in vivo and in vitro. Overexpression of miR‐340 or the silencing of SPP1 inhibited GC cell proliferation, invasion, migration, and EMT process, but promoted apoptosis of GC cells. Typically, targeting of SPP1 by miR‐340 may contribute to the inhibition of proliferation, migration, invasion, and EMT of GC cells via suppression of PI3K/AKT signaling pathway.
Targeting of secreted phosphoprotein 1 (SPP1) by microRNA‐340 (miR‐340) may contribute to the inhibition of proliferation, migration, invasion, and epithelial–mesenchymal transition (EMT) of gastric cancer (GC) cells via suppression of phosphatidylinositol 3‐kinase/protein kinase B (PI3K/AKT) signaling pathway.
Developmental arrest, a critical component of the life cycle in animals as diverse as nematodes (dauer state), insects (diapause), and vertebrates (hibernation), results in dramatic depression of the ...metabolic rate and a profound extension in longevity. Although many details of the hormonal systems controlling developmental arrest are well-known, we know little about the interactions between metabolic events and the hormones controlling the arrested state. Here, we show that diapause is regulated by an interplay between blood-borne metabolites and regulatory centers within the brain. Gene expression in the fat body, the insect equivalent of the liver, is strongly suppressed during diapause, resulting in low levels of tricarboxylic acid (TCA) intermediates circulating within the blood, and at diapause termination, the fat body becomes activated, releasing an abundance of TCA intermediates that act on the brain to stimulate synthesis of regulatory peptides that prompt production of the insect growth hormone ecdysone. This model is supported by our success in breaking diapause by injecting a mixture of TCA intermediates and upstream metabolites. The results underscore the importance of cross-talk between the brain and fat body as a regulator of diapause and suggest that the TCA cycle may be a checkpoint for regulating different forms of animal dormancy.
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•Threatened conifers endemic to China were mainly distributed in mountainous areas.•The Western Sichuan Plateau is the most important conservation priority area.•Richness hotspots ...were predicted to shrink and move northward under climate change.•Species with different distributions required different conservation measures.•Additional field surveys and integration of reserves are needed for protection.
Climate change inevitably affects the geographical distribution of species on earth. Conifers, which are important components of forest tree species, are highly threatened and particularly sensitive to climate change. Approximately 23.6% (145/615 species) of the world’s conifers are native to China, among which 53 species are threatened. Thus, understanding the impact of climate change on the species richness and distribution of threatened conifers endemic to China (hereafter referred to as threatened conifers) is of great importance. Here, we investigated the habitat suitability under present climate conditions and predicted the impact of future climate change on these threatened conifers using species distribution modeling. Combined with the current natural reserve system, we evaluated the conservation effectiveness, determined the key conservation areas, and proposed suggestions for the future protection of these threatened conifers. Our results showed that the threatened conifers were mainly distributed in mountainous areas and climate variables played a major role in the distribution of these threatened conifers. We also found that the richness hotspots were predicted to shrink and move northward with a changing climate. The lowest elevation of threatened conifers predicted to contract their species range mainly occurred below 1000 m or above 2000 m, while most species whose lowest elevations ranged from 1000 to 2000 m were projected to expand their distribution areas under the future climate scenario. Therefore, different conservation measures should be taken for threatened conifers with different distribution patterns. The central Hengduan Mountains and the Western Sichuan Plateau were identified as “areas needing attention” and “areas worth exploring”, respectively, which should be given more attention in future field surveys and conservation efforts. This study highlighted the critical role of these threatened conifers as good indicators for measuring and proposing conservation strategies to minimize the impacts of climate change.
Cornus officinalis is one of the most widely used medicinal plants in China and other East Asian countries to cure diseases such as liver, kidney, cardiovascular diseases and frequent urination for ...thousands of years. It is a Level 3 protected species, and is one of the 42 national key protected wild species of animals and plants in China. However, the genetics and molecular biology of C. officinalis are poorly understood, which has hindered research on the molecular mechanism of its metabolism and utilization. Hence, enriching its genomic data and information is very important. In recent years, the fast-growing technology of next generation sequencing has provided an effective path to gain genomic information from nonmodel species. This study is the first to explore the leaf and fruit tissue transcriptome of C. officinalis using the Illumina HiSeq 4000 platform. A total of 57,954,134 and 60,971,652 clean reads from leaf and fruit were acquired, respectively (GenBank number SRP115440). The pooled reads from all two libraries were assembled into 56,392 unigenes with an average length 856 bp. Among these, 41,146 unigenes matched with sequences in the NCBI nonredundant protein database. The Gene Ontology database assigned 24,336 unigenes with biological process (83.26%), cellular components (53.58%), and molecular function (83.93%). In addition, 10,808 unigenes were assigned a KOG functional classification by the KOG database. Searching against the KEGG pathway database indicated that 18,435 unigenes were mapped to 371 KEGG pathways. Moreover, the edgeR database identified 4,585 significant differentially expressed genes (DEGs), of which 1,392 were up-regulated and 3,193 were down-regulated in fruit tissue compared with leaf tissue. Finally, we explored 581 transcription factors with 50 transcription factor gene families. Most DEGs and transcription factors were related to terpene biosynthesis and secondary metabolic regulation. This study not only represented the first de novo transcriptomic analysis of C. officinalis but also provided fundamental information on its genes and biosynthetic pathway. These findings will help us explore the molecular metabolism mechanism of terpene biosynthesis in C. officinalis.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A strategy known as diapause (developmental arrest) has evolved in insects to increase their survival rate under harsh environmental conditions. Diapause causes a dramatic reduction in the metabolic ...rate and drastically extends lifespan. However, little is known about the mechanisms underlying the metabolic changes involved. Using gas chromatography-mass spectrometry, we compared the changes in the metabolite levels in the brain and hemolymph of nondiapause- and diapause-destined cotton bollworm, Helicoverpa armigera, during the initiation, maintenance, and termination of pupal diapause. A total of 55 metabolites in the hemolymph and 52 metabolites in the brain were detected. Of these metabolites, 21 and 12 metabolite levels were altered in the diapause pupal hemolymph and brain, respectively. During diapause initiation and maintenance, the number of metabolites with increased levels in the hemolymph of the diapausing pupae is far greater than the number in the nondiapause pupae. These increased metabolites function as an energy source, metabolic intermediates, and cryoprotectants. The number of metabolites with decreased levels in the brain of diapausing pupae is far greater than the number in the nondiapause pupae. Low metabolite levels are likely to directly or indirectly repress the brain metabolic activity. During diapause termination, most of the metabolite levels in the hemolymph of the diapausing pupae rapidly decrease because they function as energy and metabolic sources that promote pupa-adult development. In conclusion, the metabolites with altered levels in the hemolymph and brain serve as energy and metabolic resources and help to maintain a low brain metabolic activity during diapause.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Diapause, a state of arrested development accompanied by a marked decrease of metabolic rate, helps insects to overcome unfavorable seasons. Helicoverpa armigera (Har) undergoes pupal diapause, but ...the molecular mechanism of diapause initiation is unclear. Using suppression subtractive hybridization (SSH), we investigated differentially expressed genes in diapause- and nondiapause-destined pupal brains at diapause initiation.
We constructed two SSH libraries (forward, F and reverse, R) to isolate genes that are up-regulated or down-regulated at diapause initiation. We obtained 194 unique sequences in the F library and 115 unique sequences in the R library. Further, genes expression at the mRNA and protein level in diapause- and nondiapause-destined pupal brains were confirmed by RT-PCR, Northern blot or Western blot analysis. Finally, we classified the genes and predicted their possible roles at diapause initiation.
Differentially expressed genes at pupal diapause initiation are possibly involved in the regulation of metabolism, energy, stress resistance, signaling pathways, cell cycle, transcription and translation.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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