D1 Protein Research Articles

YKL-06-061 exerts antitumor effect through G1/S phase arrest by downregulating c-Myc and inhibition of metastasis via SIK1 upregulation in pancreatic cancer.

Pancreatic cancer ranks fourth among cancer-related deaths with a low 5-year overall survival rate of less than 13%. At present, treatment of pancreatic cancer is still based on chemotherapy, but the efficacy is limited. Thus, a novel therapeutic agent for pancreatic cancer therapy is urgently needed. A library of compounds was screened, and YKL-06-061, a selective inhibitor of salt-inducible kinases (SIKs), was discovered for its ability of inhibiting the proliferation and metastasis of pancreatic cancer cells in vitro and reducing the growth of xenografts in nude mice in vivo. The results from transcriptome analysis showed that YKL-06-061 influenced the mRNA levels of many genes related to c-Myc and SIK1 signals. Based on this, it was found that YKL-06-061 induced cell cycle arrest at the G1 phase and decreased the levels of c-Myc, CDK4, and cyclin D1 protein. At the same time, YKL-06-061 inhibited invasion and metastasis of cancer cells, increased the levels of SIK1 and E-cadherin protein, and lowered vimentin and ZEB-1. Moreover, YKL-06-061 effectively enhanced the antiproliferation of gemcitabine or doxorubicin in pancreatic cancer cells in a synergistic manner. Collectively, these findings implicate YKL-06-061 as a promising therapeutic agent for patients with pancreatic cancer.

E2F8 facilitates malignant phenotypes of muscle-invasive bladder cancer via increasing MCM7 expression.

E2F transcription factor 8 (E2F8) is an important regulator of the cell cycle. In this study, we first assessed the expression of E2F8 in bladder cancer and examined its effects in the malignant phenotypes of bladder cancer cell lines. We found that E2F8 was upregulated in bladder cancer tissues, and the increased expression was positively associated with higher clinical stage. E2F8 knockdown suppressed bladder cancer cell proliferation, accompanied by the performance of G1 phase arrest and the upregulated Cyclin D1 protein expression. The migrative and invasive capability was reduced in E2F8-depleted bladder cancer cells. Cisplatin resistance is an important cause of bladder cancer relapse. E2F8 downregulation facilitated cisplatin-induced apoptosis of bladder cancer cells. MCM7 is regulated by E2F and has been shown to participate in bladder cancer. There was a positive correlation between E2F8 and MCM7 expression in bladder cancer. We confirmed that E2F8 bound to the promoter region of MCM7 and activated MCM7 transcription. MCM7 overexpression abrogated the suppressive effects of E2F8 knockdown on malignant phenotypes of bladder cancer cells. We also demonstrated that E2F8 knockdown suppressed bladder cancer progression in vivo. In conclusion, we verify that E2F8 functioned in bladder cancer, and might exert its function via MCM7.

Ancient duplication and functional differentiation of phytochelatin synthases is conserved in plant genomes

Summary Despite the paramount importance in metal(loid) detoxification by phytochelatin synthase (PCS) genes, no comprehensive analysis of their evolutionary patterns has been carried out in land plants in general and in crops in particular. A phylogenetic large-scale analysis of gene duplication in angiosperms was carried out followed by in vitro recombinant protein assays as well as complementation analysis (growth, thiol-peptides, elements) of Arabidopsis cad1-3 mutant with four representative PCS genes from two model crop species, Malus domestica and Medicago truncatula. We uncovered a so far undetected ancient tandem duplication (D duplication) spanning the whole core eudicotyledon radiation. Complementation with PCS genes from both D-subclades from M. domestica and M. truncatula displayed clear in vivo conservation of the differences between D1 and D2 paralogous proteins in plant growth, phytochelatin and glutathione pools, as well as element contents under heavy metal(loid) stress. In vitro recombinant PCS analysis identified analogous patterns of differentiation, showing a higher activity of D2 PCS genes, so far largely overlooked, compared to their paralogs from the D1 clade. This suggests that in many other crop species where the duplication is present, the D2 copy might play a significant role in metal(loid) detoxification. The retention of both PCS paralogs and of their functional features for such long divergence time suggests that PCS copy number could be constrained by functional specialization and/or gene dosage sensitivity. These results uncover the patterns of PCS evolution in plant genomes and of functional specialization of their paralogs in the genomes of two important model crops.

Clinical significance of Cyclin D1 by complete quantification detection in mantle cell lymphoma: positive indicator in prognosis

ObjectivesThe positive expression of Cyclin D1 in immunohistochemical (IHC) staining serves as the cornerstone for diagnosing mantle cell lymphoma (MCL). However, existing literature does not conclusively establish whether the expression ratio and staining intensity significantly influence diagnostic outcomes or patient prognosis. In this retrospective study, the correlation between comprehensive Cyclin D1 quantification and the prognosis of MCL patients was studied.MethodsThe Cyclin D1 protein level was assessed in 120 formalin-fixed paraffin-embedded samples from MCL patients using the quantitative dot blot (QDB) analysis technique. R language software was employed for statistical analysis to determine the optimal threshold with statistical significance. Additionally, Kaplan-Meier method was utilized to evaluate the relationship between the absolute level of Cyclin D1 protein and overall survival (OS) of patients. Furthermore, the Chi-square test was applied to analyze the causes of single and multiple fractures, with a significance level of p < 0.05. Finally, the Log-rank test was used to compare two survival curves, where a significance level of p < 0.05 was considered statistically significant.ResultsAt the optimized cutoff of 0.46 nmol/g, univariate analysis revealed a positive correlation between Cyclin D1 protein level and patient survival (OS). Specifically, in the subgroup with complete quantification of Cyclin D1 higher than the cutoff, the 5-year OS was 18%, whereas in the subgroup with complete quantification of Cyclin D1 lower than the cutoff, the 5-year OS was 4.8% (Log-rank test, P = 0.017). This indicates that patients with Cyclin D1 levels above the cutoff had significantly better overall survival compared to those below the cutoff. Additionally, in the Pearson distribution test, Ki-67 emerged as an independent prognostic factor for the complete quantification of Cyclin D1. Notably, Cyclin D1 complete quantification results remained unaffected by factors such as gender, age, LDH (Lactate Dehydrogenase) level, Ann Arbor stage(AAS), Ki-67, IPI(International prognostic index), MIPI(Mantle International prognostic index), and MIPI-c (MIPI Combined with Ki-67 Proliferation Index Chi-square test, p > 0.05).ConclusionsComprehensive Cyclin D1 quantification, especially above a threshold, significantly correlates with better overall survival in MCL. This highlights its prognostic importance in MCL management. Full quantification of CyclinD1 aids MCL prognosis, while QDB technology for biomarker quantification supports precise clinical prognostic stratification.

Repurposing of sericin combined with dactolisib or vitamin D to combat non-small lung cancer cells through computational and biological investigations

This study aims to repurpose sericin in combating non-small lung cancer cells (A549 and H460) by combining it with dactolisib or vitamin D to reduce the dose of dactolisib and boost the anticancer effectiveness of dactolisib and vitamin D. Therefore, the binding affinities of individual and combined drugs were examined using in silico and protein-protein interaction studies, targeting NF-κB, Cyclin D1, p-AKT, and VEGF1 proteins. The findings manifested remarkable affinities for combinatorial drugs compared to individual compounds. To substantiate these findings, the combined IC50 for each combination (sericin + dactolisib and sericin + vitamin D) were determined, reporting 31.9 and 41.8 µg/ml, respectively, against A549 cells and 47.9 and 55.3 µg/ml, respectively, against H460 cells. Furthermore, combination indices were assessed to lower the doses of each drug. Interestingly, in vitro results exhibited marked diminutions in NF-κB, Cyclin D1, p-AKT, and VEGF1 after treatment with sericin + dactolisib and sericin + vitamin D compared to control lung cancer cells and those treated with a single drug. Moreover, A549 and H460 cells treated with both combinations demonstrated augmented caspase-3 levels, implying substantial apoptotic activity. Altogether, these results accentuated the prospective implementation of sericin in combination with dactolisib and vitamin D at low doses to preclude lung cancer cell proliferation.

Evaluation of Cyclin D1 protein and its association with the clinicopathological characteristics and prognosis of lung cancer: A retrospective study from Southern Kerala, India.

Cyclin D1 is a protein that can enhance the proliferation of cancer cells and has been detected in various malignancies, including lung cancer. However, routine examinations for Cyclin D1 in lung cancer cases have not been conducted in Kerala. This study sought to evaluate the links between cyclin D1 expression, clinicopathological characteristics, and 2-year survival rates in lung cancer. This retrospective cohort study used medical records and paraffin blocks of lung cancer patients at the Regional Cancer Centre in Kerala, India, between 2015 and 2018. The data were collected from 61 subjects, comprising of lung adenocarcinoma (18%), lung squamous cell carcinoma (27.9%), non-small-cell lung carcinoma (18%), poorly differentiated carcinoma (19.7%), and negative for malignant cells (16.4%). Data analysis was conducted using SPSS. The study revealed that 31.10% of the lung cancer patients exhibited overexpression of cyclin D1. A significant correlation was observed between cyclin D1 expression and histopathological results (P = 0.002), indicating that the level of cyclin D1 might be linked to specific histopathological subtypes of lung cancer. Despite this significant finding, cyclin D1 expression did not show any association with the clinical stage of the cancer or other clinical characteristics of the patients. Furthermore, when examining the 2-year survival rates of the patients, the study found no significant difference between those who had overexpression of cyclin D1 and those who did not (P = 0.145). Cyclin D1 expression was associated with histology type of lung cancer with no significant association to prognosis.

Molecular signatures of environmental adaptation mechanisms of Rhizocarpon geographicum in Horseshoe Island (west of the Antarctic Peninsula) and Türkiye

The adaptation of lichen species to different habitats and extreme conditions is due to rapid changes in expressions of the genes in their genetic backgrounds. In this study, lichen samples were collected from two different regions: from Horseshoe Island, located to the west of the Antarctic Peninsula and from the west coast of Türkiye. The nrITS gene regions of the samples were studied and the phylogenetic positions of the samples were confirmed as Rhizocarpon geographicum (L.) DC. After DNA barcoding of R. geographicum, expression differences of three below-specified stress genes were revealed. Comparative determinations of the changes in the expressions of the multiprotein binding factor-1 (MBF-1), polyketide synthase (PKS), and photosystem II D1 protein (psbA) genes due to temperature or other environmental stress change stress were performed by a real-time PCR. Specifically, under cold stress conditions such as those found on Horseshoe Island, the MBF-1 gene was highly expressed, while PKS and psbA gene expression levels were lower compared to the west coast of Türkiye. The results of this study, which is the first in its field, highlight the adaptation of Rhizocarpon geographicum specimens to those habitats and regional climate. Specimen collected from different geographical regions exhibited gene expression differences.

Downregulation of lncRNA-MALAT1, Altered Immunohistochemical Expression of Cyclin D1 Protein and E-Cadherin Protein in Correlation to Meningioma Grades.

Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is known to be upregulated in the tumors with ability to metastasize. In contrast, long non-coding Ribonuclei acid (lncRNA) MALAT1 was reported by some studies to be downregulated in meningioma cells. E-cadherin and Cyclin D1 are prognostic indicators and possible attractive targets for the treatment of recurring and aggressive meningioma. This study aimed to evaluate the expression level of lncRNA MALAT1, as well as Cyclin D1 and E-cadherin immunohistochemical expression in meningiomas (Grade 1 and 2) and their association with the clinicopathological parameters of the studied cases. Quantitative determination of relative expression levels of lncRNA-MALAT1 in 64 cases of meningioma to 5 controls of normal dura mater was performed, in addition to evaluation of E-cadherin and Cyclin D1 immunohistochemical expression. The results were tested for association with the clinicopathological parameters. lncRNA-MALAT1 expression were downregulated in 49/64 of the cases of meningioma (76%) in comparison to control. There were significant association of expression of lncRNA-MALAT1 with grade, brain invasion and increased mitosis (p=0.007, 0.04, 0.006 respectively). There were also significant associations of strong E-cadherin and negative Cyclin D1 proteins expression with grade 1 (p = 0.02, 0.004), low mitosis (p=0.03, and 0.04) and brain invasion (p=0.04, 0.03) respectively. Additionally, a significant weak negative correlation between E-cadherin and Cyclin D1 expression was fond, yet no significant correlation between lncRNA MALAT1 expression and either of E-cadherin or Cyclin D1 expression could be achieved. lncRNA MALAT1 is downregulated in meningiomas and associated with increased aggressiveness. Overexpressed cyclin D1 and decreased E-cadherin expression are also associated with high grade meningioma.

Association of Genetic Variants at the CDKN1B and CCND2 Loci Encoding p27Kip1 and Cyclin D2 Cell Cycle Regulators with Susceptibility and Clinical Course of Chronic Lymphocytic Leukemia.

Beyond the essential role of p27Kip1 and cyclin D2 in cell cycle progression, they are also shown to confer an anti-apoptotic function in peripheral blood (PB) lymphocytes. Although the aberrant longevity and expression of p27Kip1 and cyclin D2 in leukemic cells is well documented, the exact mechanisms responsible for this phenomenon have yet to be elucidated. This study was undertaken to determine the associations between polymorphisms in the CDKN1B and CCND2 genes (encoding p27Kip1 and cyclin D2, respectively) and susceptibility to chronic lymphocytic leukemia (CLL), as well as their influence on the expression of both cell cycle regulators in PB leukemic B cells and non-malignant T cells from untreated CLL patients divided according to the genetic determinants studied. Three CDKN1B single-nucleotide polymorphisms (SNPs), rs36228499, rs34330, and rs2066827, and three CCND2 SNPs, rs3217933, rs3217901, and rs3217810, were genotyped using a real-time PCR system. The expression of p27Kip1 and cyclin D2 proteins in both leukemic B cells and non-malignant T cells was determined using flow cytometry. We found that the rs36228499A and rs34330T alleles in CDKN1B and the rs3217810T allele in the CCND2 gene were more frequent in patients and were associated with increased CLL risk. Moreover, we observed that patients possessing the CCND2rs3217901G allele had lower susceptibility to CLL (most pronounced in the AG genotype). We also noticed that the presence of the CDKN1Brs36228499CC, CDKN1Brs34330CC, CDKN1Brs2066827TT, and CCND2rs3217901AG genotypes shortened the time to CLL progression. Statistically significant functional relationships were limited to T cells and assigned to CDKN1B polymorphic variants; carriers of the polymorphisms rs34330CC and rs36228499CC (determining the aggressive course of CLL) expressed a decrease in p27Kip1 and cyclin D2 levels, respectively. We indicate for the first time that genetic variants at the CDKN1B and CCND2 loci may be considered as a potentially low-penetrating risk factor for CLL and determining the clinical outcome.

Resistance to the herbicide metribuzin conferred to Arabidopsis thaliana by targeted base editing of the chloroplast genome.

The chloroplast genome has considerable potential to enhance crop productivity, but it remains underutilized in breeding because it is difficult to modify. This study elucidates the potential of recently developed chloroplast-targeted C-to-T base editors in facilitating the use of the chloroplast genome for crop breeding. The herbicide metribuzin interferes with photosynthesis by binding to the D1 protein of photosystem II, encoded by the chloroplast genome. Naturally occurring D1 mutants with V219I or A251V substitutions are known to have resistance to some herbicides including metribuzin. Here, using the base editors, we introduced these substitutions and showed that the A251V single mutation and the V219 & A251V double mutations conferred significant metribuzin resistance to Arabidopsis thaliana. The V219I & A251V double mutants exhibited increased metribuzin resistance and grew better than the A251V single mutants. Furthermore, the double mutants grew as well as wild-type plants in the absence of metribuzin. The single and double mutants, which are a challenge to obtain through traditional mutagenesis and crossbreeding methods, can be relatively easily generated using C-to-T base editors. In view of the conservation of V219 and A251 across numerous species, C-to-T base editing can potentially confer metribuzin resistance to a wide range of crops. Compared to nuclear genes, chloroplast genes are also less likely to spread into wild populations. Our findings suggest that chloroplast-targeting C-to-T base editors will find many roles in future crop breeding efforts.

Oncogenic accumulation of cysteine promotes cancer cell proliferation by regulating the translation of D-type cyclins

Malignant cells exhibit a high demand for amino acids to sustain their abnormal proliferation. Particularly, the intracellular accumulation of cysteine is often observed in cancer cells. Previous studies have shown that deprivation of intracellular cysteine in cancer cells results in the accumulation of lipid peroxides in the plasma membrane and induction of ferroptotic cell death, indicating that cysteine plays a critical role in the suppression of ferroptosis. Herein, we found that the oncogenic accumulation of cysteine also contributes to cancer cell proliferation by promoting the cell cycle progression, which is independent of its suppressive effect on ferroptosis. The growth ability of four types of cancer cells, including murine hepatocarcinoma cells, but not of primary hepatocytes, were dependent on the exogenous supply of cysteine. Deprivation of intracellular cysteine in cancer cells induced cell cycle arrest at the G0/G1 phase, accompanied by a decrease in the expression of cyclin D1 and D2 proteins. The cysteine deprivation-induced decrease in D-type cyclin expression was associated with the upregulation of eukaryotic translation initiation factor 4E binding protein (4E-BP1), which represses the translation of cyclin D1 and D2 proteins by binding to eukaryotic translation initiation factor 4E (eIF4E). Similar results were observed in hepatocarcinoma cells treated with erastin, an xCT inhibitor. These findings reveal an unappreciated role of cysteine in regulating the growth of malignant cancer cells and deepen our understanding of the cytotoxic effect of xCT inhibitor to prevent cancer cell proliferation.

Effects of Down-Regulation of PAK1 on Differentiation and Apoptosis of MPN Cells with MPLW515L Gene Mutation and Survival of 6133/MPL Mice

To investigate the effects of down-regulation of p21 activated kinase 1 (PAK1) on the proliferation, differentiation, and apoptosis of myeloproliferative neoplasm (MPN) cells (6133/MPL) with thrombopoietin receptor MPL mutation at codon 515 (MPLW515L) and survival of 6133/MPL mice. Interference with the protein level of PAK1 in 6133/MPL cells was assessed using lentivirus-mediated shRNA transfection technology. CCK-8 assay was used to detect the effect of down-regulation of PAK1 on the proliferation viability of 6133/MPL cells, and colony-forming ability was measured by cell counting. Flow cytometry was used to detect the PAK1 kinase activity on the ability of polyploid DNA formation and cell apoptosis in 6133/MPL cells. The expression of cyclin D1, cyclin D3 and apoptosis-related protein Bax was detected by Western blot. The infiltration of tumor cells in spleen and bone marrow of 6133/MPL mice were detected by HE staining. Down-regulation of PAK1 inhibited the proliferation and reduced the ability of cell colony formation of 6133/MPL cells. After knocking down PAK1, the content of polyploid DNA in 6133/MPL cells increased from 31.8 to 57.5% and 48.0%, and the proportion of apoptosis increased approximately to 10.8%. Down-regulation of PAK1 led to a reduction of infiltration of tumor cells in liver and bone marrow of 6133/MPL mice, thereby prolonging survival time. Down-regulation of PAK1 can significantly inhibit the growth of 6133/MPL cells, promote the formation of polyploid DNA, induce 6133/MPL cell apoptosis, and prolong the survival time of 6133/MPL mice.

Phe265 of the D1 protein is required to stabilize plastoquinone binding in the QB-binding site of photosystem II in Synechocystis sp. PCC 6803

In Photosystem II electrons from water splitting pass through a primary quinone electron acceptor (QA) to the secondary plastoquinone (QB). The D2 protein forms the QA-binding site and the D1 protein forms the QB-binding site. A non-heme iron sits between QA and QB resulting in a quinone-Fe-acceptor complex that must be activated before assembly of the oxygen-evolving complex can occur. An extended loop (residues 223–266) between the fourth (helix D) and fifth (helix E) helices of the D1 protein activates forward electron transfer via a conformational change that stabilizes a bidentate bicarbonate ligand to the non-heme iron while simultaneously stabilizing the binding of QB. We show that positioning of D1:Phe265 to provide a hydrogen bond to the distal oxygen of QB is required for forward electron transfer. In addition, mutations targeting D1:Phe265, resulted in a 50 mV decrease in the QB/QB– midpoint potential.

The effectiveness of biotin in therapy alopecia of various origins, pathologies of the skin and nails

Biotin deficiency is caused by inflammatory bowel diseases that impair the absorption of the vitamin, special dietary disorders with the consumption of raw eggs (excess avidin – a vitamin B7 blocker protein), magnesium deficiency, smoking, alcohol, treatment with broad-spectrum antibiotics, sulfonamides, and anticonvulsants. Hypovitaminosis B7 has also been noted in individuals with congenital genetic defects of the biotinidase gene or other genes involved in biotin metabolism. Deficiency of water-soluble vitamin B7 (vitamin H) – manifested by dry skin, seborrheic dermatitis, dermatitis around the eyes, nose, mouth, ears and groin, impaired nail growth, slow healing of skin cuts, atopic dermatitis, striations, splitting, brittle nails and alopecia (diffuse and androgenic form). Alopecia occurs when hair follicles die and leads to hair loss. The human proteome contains 51 proteins involved in biotin metabolism. In particular, D-biotin-dependent carboxylases play an important role in the metabolism of fatty acids, amino acids, carbohydrates, cell division and growth, incl. keratinocytes and hair follicle cells. The molecular mechanisms of the effects of D-biotin on the skin and its appendages may involve various growth factors: regulation of the signaling pathways of growth factors (IGF-1, FGF, KGF, HGF, VEGF, SIRT-1, Wnt and beta-catenin) has been shown. Hair follicle stem cells cause the cyclical growth of hair follicles. Growth factors are involved in the activation of stem cell growth by D-biotin; activation of the Wnt/β-catenin signaling cascade leads to the activation of cyclin D1 proteins (initiates DNA synthesis and leads to increased viability of hair follicles. The results of fundamental and clinical studies confirm the prospects of using biotin in dermatology for the treatment of diseases of the skin, hair and nails, incl. alopecia of various origins (androgenic, focal, diffuse). The results of the studies indicated that biotin was well tolerated, and there was no risk of hypervitaminosis even when taking megadoses (hundreds of milligrams).

Expression and localization of Cyclin D1/Nanog and NF-κB/Bax protein in dysplastic testicles of mice

Testicular dysplasia significantly impairs male reproductive capacity. This study investigated the expression of Cyclin D1/Nanog and NF-κB/Bax in dysplastic testes of mice using histological staining, Western blotting, and immunohistochemistry. The results showed that Nanog and Bax expression were significantly higher in dysplastic testicular tissue than in normal tissue (P < 0.01). Cyclin D1 protein expression was higher in normal testis tissue than in dysplastic testis (P < 0.01). NF-κB was highly expressed in cryptorchid and normal testis with no significant difference (P > 0.05). Immunolocalization revealed that Nanog, NF-κB, and Bax were expressed in the cytoplasm of Leydig and spermatogenic cells. Cyclin D1 primarily expressed in the nucleus of Sertoli cells. These findings suggest that altered expression of Nanog, Cyclin D1, and Bax may contribute to testicular dysplasia. This study provides a scientific foundation for detecting testicular dysplasia and selecting appropriate animal models, ultimately informing strategies to improve male reproductive health.

STIC2 selectively binds ribosome-nascent chain complexes in the cotranslational sorting of Arabidopsis thylakoid proteins.

Chloroplast-encoded multi-span thylakoid membrane proteins are crucial for photosynthetic complexes, yet the coordination of their biogenesis remains poorly understood. To identify factors that specifically support the cotranslational biogenesis of the reaction center protein D1 of photosystem (PS) II, we generated and affinity-purified stalled ribosome-nascent chain complexes (RNCs) bearing D1 nascent chains. Stalled RNCs translating the soluble ribosomal subunit uS2c were used for comparison. Quantitative tandem-mass spectrometry of the purified RNCs identified around 140 proteins specifically associated with D1 RNCs, mainly involved in protein and cofactor biogenesis, including chlorophyll biosynthesis, and other metabolic pathways. Functional analysis of STIC2, a newly identified D1 RNC interactor, revealed its cooperation with chloroplast protein SRP54 in the de novo biogenesis and repair of D1, and potentially other cotranslationally-targeted reaction center subunits of PSII and PSI. The primary binding interface between STIC2 and the thylakoid insertase Alb3 and its homolog Alb4 was mapped to STIC2's β-sheet region, and the conserved Motif III in the C-terminal regions of Alb3/4.

The mechanisms of photoinhibition and repair in plants under high light conditions and interplay with abiotic stressors

This review comprehensively examines the phenomenon of photoinhibition in plants, focusing mainly on the intricate relationship between photodamage and photosystem II (PSII) repair and the role of PSII extrinsic proteins and protein phosphorylation in these processes. In natural environments, photoinhibition occurs together with a suite of concurrent stress factors, including extreme temperatures, drought and salinization. Photoinhibition, primarily caused by high irradiance, results in a critical imbalance between the rate of PSII photodamage and its repair. Central to this process is the generation of reactive oxygen species (ROS), which not only impair the photosynthetic apparatus first PSII but also play a signalling role in chloroplasts and other cellulular structures. ROS generated under stress conditions inhibit the repair of photodamaged PSII by suppressing D1 protein synthesis and affecting PSII protein phosphorylation. Furthermore, this review considers how environmental stressors exacerbate PSII damage by interfering with PSII repair primarily by reducing de novo protein synthesis. In addition to causing direct damage, these stressors also contribute to ROS production by restricting CO2 fixation, which also reduces the intensity of protein synthesis. This knowledge has significant implications for agricultural practices and crop improvement under stressful conditions.

High‐Performance Cooperative DNA Nanodevice Enables Sensitive Circular RNA Imaging and Precise Tumor Growth Suppression

The utility of circular RNAs (circRNAs) as emerging biomarkers and regulatory factors in medical diagnostics and therapeutics is hampered by the challenges associated with their sensitive detection and precise modulation. Herein, a high‐performance cooperative DNA nanodevice (HCDN) based on DNA tetrahedron‐confined catalytic DNA assembly reaction (DT‐CDA) that enables both imaging and regulation of circRNAs is developed. Activation of the DT‐CDA is contingent upon the presence of the target circRNA, which, together with a replicative fuel probe, catalyzes the sequential opening of additional DT‐CDAs. This cooperative exponential signal amplification with negligible background interference allows HCDN to effectively detect minute quantities of circRNAs. Employing circSATB2 as a model, the HCDN demonstrates substantial downregulation of Cyclin D1 (CCND1) mRNA and protein levels in cellular and in vivo models, thereby inhibiting tumor growth. The innovative design of HCDN sets the stage for a powerful methodology conducive to enhanced clinical diagnostics and biomolecule manipulation, thereby advancing the capabilities and applications of DNA nanotechnology.

Externally supplied ascorbic acid moderates detrimental effects of UV-C exposure in cyanobacteria.

The defensive role performed by exogenously supplied ascorbic acid in the cyanobacterium Nostoc muscorum Meg1 against damages produced by UV-C radiation exposure was assessed in this study. Exposure to UV-C (24mJ/cm2) significantly enhanced reactive oxygen species (ROS) (50%) along with peroxidation of lipids (21%) and protein oxidation (22%) in the organism. But, addition of 0.5mM ascorbic acid prior to UV-C exposure showed reduction in ROS production (1.7%) and damages to lipids and proteins (1.5 and 2%, respectively). Light and transmission electron microscopic studies revealed that ascorbic acid not only protected filament breakage but also restricted severe ultrastructural changes and cellular damages in the organism. Although the growth of the organism was repressed up to 9% under UV-C treatment within 15days, a pre-treatment with ascorbic acid led to growth enhancement by 42% in the same period. Various growth parameters such as photo-absorbing pigments (phycoerythrin, phycocyanin, allophycocyanin, chlorophyll a, and carotenoids), water splitting complex (WSC), D1 protein, RuBisCO, glutamine synthetase and nitrogenase activities in the UV-C treated organism were seen to be relatively intact in the presence of ascorbic acid. Thus, a detailed analysis undertaken in the present study was able to demonstrate that ascorbic acid not only act as first responder against harmful UV-C radiation by down-regulating ROS production, it also accelerated the growth performance in the organism in the post UV-C incubation period as an immediate response to an adverse experience presented in the form of UV-C radiation exposure.

Ginsenoside Rg1 protects the blood-brain barrier and myelin sheath to prevent postoperative cognitive dysfunction in aged mice.

In this study, the postoperative cognitive dysfunction (POCD) mouse model was established to observe the changes in inflammation, blood-brain barrier permeability, and myelin sheath, and we explore the effect of ginsenoside Rg1 pretreatment on improving POCD syndrome. The POCD model of 15- to 18-month-old mice was carried out with internal fixation of tibial fractures under isoflurane anesthesia. Pretreatment was performed by continuous intraperitoneal injection of ginsenoside Rg1(40 mg/kg/day) for 14 days before surgery. The cognitive function was detected by the Morris water maze. The contents of interleukin-1β and tumor necrosis factor-α in the hippocampus, cortex, and serum were detected by ELISA. The permeability of blood-brain barrier was observed by Evans blue. The mRNA levels and protein expression levels of 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase), myelin basic protein (MBP), beta-catenin, and cyclin D1 in the hippocampus were analyzed by quantitative PCR and western blotting. The protein expression levels of ZO-1 and Wnt1 in the hippocampus were analyzed by western blotting. Finally, the localizations of CNPase and MBP in the hippocampus were detected by immunofluorescence. Ginsenoside Rg1 can prevent POCD, peripheral and central inflammation, and blood-brain barrier leakage, and reverse the downregulation of ZO-1, CNPase, MBP, and Wnt pathway-related molecules in aged mice. Preclinical studies suggest that ginsenoside Rg1 improves postoperative cognitive function in aged mice by protecting the blood-brain barrier and myelin sheath, and its specific mechanism may be related to the Wnt/β-catenin pathway.