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The level of methylesterification alters the functional properties of pectin, which is believed to influence plant growth and development. However, the mechanisms that regulate demethylesterification remain largely unexplored. Pectin with a high degree of methylesterification is produced in the Golgi apparatus and then transferred to the primary cell wall where it is partially demethylesterified by pectin methylesterases (PMEs). Here, we show that in Arabidopsis (Arabidopsis thaliana) seed mucilage, pectin demethylesterification is negatively regulated by the transcription factor ZINC FINGER FAMILY PROTEIN5 (ZAT5). Plants carrying null mutations in ZAT5 had increased PME activity, decreased pectin methylesterification, and produced seeds with a thinner mucilage layer. We provide evidence that ZAT5 binds to a TGATCA-motif and thereby negatively regulates methylesterification by reducing the expression of PME5, HIGHLY METHYL ESTERIFIED SEEDS (HMS)/PME6, PME12, and PME16. We also demonstrate that ZAT5 physically interacts with BEL1-LIKE HOMEODOMAIN2 (BLH2) and BLH4 transcription factors. BLH2 and BLH4 are known to modulate pectin demethylesterification by directly regulating PME58 expression. The ZAT5-BLH2/4 interaction provides a mechanism to control the degree of pectin methylesterification in seed coat mucilage by modifying each transcription factor's ability to regulate the expression of target genes encoding PMEs. Taken together, these findings reveal a transcriptional regulatory module comprising ZAT5, BLH2 and BLH4, that functions in modulating the de-methylesterification of homogalacturonan in seed coat mucilage.
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BACKGROUND: The glandular trichomes of tobacco (Nicotiana tabacum) can efficiently produce secondary metabolites. They act as natural bioreactors, and their natural products function to protect plants against insect-pests and pathogens and are also components of industrial chemicals. To clarify the molecular mechanisms of tobacco glandular trichome development and secondary metabolic regulation, glandular trichomes and glandless trichomes, as well as other different developmental tissues, were used for RNA sequencing and analysis. RESULTS: By comparing glandless and glandular trichomes with other tissues, we obtained differentially expressed genes. They were obviously enriched in KEGG pathways, such as cutin, suberine, and wax biosynthesis, flavonoid and isoflavonoid biosynthesis, terpenoid biosynthesis, and plant-pathogen interaction. In particular, the expression levels of genes related to the terpenoid, flavonoid, and wax biosynthesis pathway mainly showed down-regulation in glandless trichomes, implying that they lack the capability to synthesize certain exudate compounds. Among the differentially expressed genes, 234 transcription factors were found, including AP2-ERFs, MYBs, bHLHs, WRKYs, Homeoboxes (HD-ZIP), and C2H2-ZFs. These transcription factor and genes that highly expressed in trichomes or specially expressed in GT or GLT. Following the overexpression of R2R3-MYB transcription factor Nitab4.5_0011760g0030.1 in tobacco, an increase in the number of branched glandular trichomes was observed. CONCLUSIONS: Our data provide comprehensive gene expression information at the transcriptional level and an understanding of the regulatory pathways involved in glandular trichome development and secondary metabolism.
Subject(s)
Gene Expression Profiling , Gene Expression Regulation, Plant , Nicotiana , Trichomes , Trichomes/genetics , Trichomes/metabolism , Trichomes/growth & development , Nicotiana/genetics , Nicotiana/metabolism , Nicotiana/growth & development , Transcriptome , Plant Proteins/genetics , Plant Proteins/metabolism , Genes, Plant , Transcription Factors/genetics , Transcription Factors/metabolismABSTRACT
Background: The timing and incidence of recurrent bone metastasis (BM) after radical gastrectomy in patients with gastric cancer (GC) as well as the survival of these patients were not fully understood. The aim of this study was to analyze the data of an observational GC cohort and identify patients who underwent curative gastrectomy and had recurrent BM to describe and clarify the pattern and profile of BM evolution after surgery. Methods: Data were retrieved from a hospital-based GC cohort, and patients who underwent upfront radical gastrectomy were selected. The time points of specific organ metastatic events were recorded, and the person-year incidence rate of metastatic events was calculated. The latency period of BM events after gastrectomy was measured and compared with that of the other two most common metastatic events, liver metastasis (LM) and distant lymph node metastasis (LNM), using analysis of variance. Propensity score matching and subgroup analysis were used for sensitivity analysis. Results: A total of 1324 GC cases underwent radical gastrectomy between January 2011 and December 2021. Of these, 67 BM, 218 LM, and 248 LNM occurred before the last follow-up. The incidence of BM events was 1.7/100 person-years, which was approximately 3-fold lower than that of LM and distant LNM events (5.5 and 6.3 per 100 person-years, respectively). BM events had a significantly longer latency (median time, 16.5 months) than LM and LNM events (11.1 and 12.0 months, respectively). Recurrent BM led to a worse prognosis (median survival, 4.5 months) than those of LM and LNM events (median survival, 7.7 and 7.1 months, respectively). However, no difference in overall survival after gastrectomy was observed among the groups. Conclusions: Compared with other common metastatic events, BM in GC after gastrectomy is a late-onset event indicating poor survival. Trial registration: No. ChiCTR1800019978; http://www.chictr.org.cn/.
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BACKGROUND: Gastric cancer liver metastasis (GCLM) patients usually accompany by abnormal serum liver function tests (LFTs) more or less; however, the prognostic value of LFTs is not fully understood. This study aimed to develop a liver chemistry score (LCS) based on LFTs and incorporate it into prognosis determination for GCLM patients who received palliative chemotherapy. METHODS: Data were derived from hospitalized GCLM patients in two general hospitals in China. LCS was generated based on the results of LFTs by LASSO regression. Cutoff value of the score was determined by restricted cubic spline. The score was then incorporated into Cox regression analysis to construct a predictive nomogram; the model was then evaluated internally and externally by AUC of time-dependent receiver operating characteristic curves (ROC) and calibration curves. RESULTS: Three hundred and thirty-six and 72 patients were included in development and validation cohort, respectively. LASSO regression analysis in development cohort finally reached a two-parametric LCS calculated on AST and ALP levels as 0.03343515 × ln (AST, U/L) + 0.02687997 × ln (ALP, U/L), and 0.232 was set as optimal cutoff value. Patients in low (LCS < 0.232) or high (LCS ≥ 0.232) score group experienced different survival times; median OS was 13.54 (95% CI: 11.1-15.6) months in the low LCS group and 7.3 (6.6-9.3) months in the high LCS group (p < 0.001). A nomogram including LCS and other clinical parameters was constructed and showed superior performance than model not including LCS. AUC of 6-month ROC improved from 0.647 (95% CI: 0.584-0.711) to 0.699 (0.638-0.759) in internal validation, and 0.837 (0.734-0.940) to 0.875 (0.784-0.966) in external validation. CONCLUSIONS: Liver chemistry score is useful in determining the prognosis of gastric cancer patients with liver metastasis and may be helpful to clinicians in decision-making.
Subject(s)
Liver Neoplasms , Stomach Neoplasms , Humans , Stomach Neoplasms/pathology , Prognosis , NomogramsABSTRACT
Tumor metastasis is a common event in patients with gastric cancer (GC) who previously underwent curative gastrectomy. It is meaningful to employ high-volume clinical data for predicting the survival of metastatic GC patients. We aim to establish an improved machine learning (ML) classifier for predicting if a patient with metastatic GC would die within 12 months. Eligible patients were enrolled from a Chinese GC cohort, and the complete detailed information from medical records was extracted to generate a high-dimensional dataset. Appropriate feature engineering and feature filter were conducted before modeling with eight algorithms. A 10-fold cross validation (CV) nested in a holdout CV (8:2) was employed for hyperparameter tuning and model evaluation. Model selection was based on the area under the receiver operating characteristic (AUROC) curve, recall, and precision. The selected model was globally explained using interpretable surrogate models. Of the total 399 cases (median survival of 8.2 months), 242 patients survived less than 12 months. The linear discriminant analysis (LDA), support vector machine (SVM), and random forest (RF) model had the highest AUROC (0.78 ± 0.021), recall (0.93 ± 0.031), and precision (0.80 ± 0.026), respectively. The LDA model created a new function that generally separated the two classes. The predicted probability of the SVM model was interpreted using a linear regression model visualized by a nomogram. The predicted class of the RF model was explained using a decision tree model. In summary, analyzing high-volume medical data by ML is helpful to produce an improved model for predicting the survival in patients with metastatic GC. The algorithm should be carefully selected in different practical scenarios.
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To understand the genetic structure of the protected turtle species Pelochelys cantorii we used transcriptome data to design more than 30,000 tri- and tetranucleotide repeat microsatellite primer pairs, of which 230 pairs were used for laboratory experiments. After two screenings, only 10 microsatellite markers with good specificity, high amplification efficiency, and polymorphisms were obtained. Using the selected primers, two multiplex PCR systems were established to compare and analyze the genetic diversity of artificially assisted breeding generations from four parents (two females and two males) continuously bred over two years. A total of 25 alleles were detected among the 10 microsatellite loci of the offspring. The polymorphism information content (PIC) was 0.313-0.674, with an average of 0.401, among which two loci were highly polymorphic (PIC ≥ 0.5). The number of alleles was 2-5 and the number of effective alleles was 1.635-3.614. The observed heterozygosity was 0.341-0.813, with an average of 0.582, whereas the average expected heterozygosity was 0.389-0.725, with an average of 0.493. Moreover, on the basis of Nei's genetic distance and the Bayesian clustering algorithm, the 182 offspring were divided into two subgroups, and the results corresponded to the two maternal lines. This is the first study to investigate the molecular markers of P. cantorii, and the results obtained can be used to protect genetic resources and provide a genetic basis for the design of population recovery plans.
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The pectin methylesterases (PMEs) play multiple roles in regulating plant development and responses to various stresses. In our study, a total of 121 PME genes were identified in the tobacco genome, which were clustered into two groups based on phylogenetic analysis together with Arabidopsis members. The investigations of gene structure and conserved motif indicated that exon/intron and motif organizations were relatively conserved in each group. Additionally, several stress-related elements were identified in the promoter region of these genes. The survey of duplication events revealed that segmental duplications were critical to the expansion of the PME gene family in tobacco. The expression profiles analysis revealed that these genes were expressed in various tissues and could be induced by diverse abiotic stresses. Notably, NtPME029 and NtPME043, were identified as homologues with AtPME3 and AtPME31, respectively. Furthermore, NtPME029 was highly expressed in roots and the over-expression of the NtPME029 gene could promote the development of roots. While NtPME043 could be induced by salt and ABA treatments, and the over-expression of the NtPME043 gene could significantly enhance the salt-stress tolerance in tobacco. Overall, these findings may shed light on the biological and functional characterization of NtPME genes in tobacco.
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PURPOSE: This study aimed to identify prognostic factors for patients with distant lymph node-involved gastric cancer (GC) using a machine learning algorithm, a method that offers considerable advantages and new prospects for high-dimensional biomedical data exploration. MATERIALS AND METHODS: This study employed 79 features of clinical pathology, laboratory tests, and therapeutic details from 289 GC patients whose distant lymphadenopathy was presented as the first episode of recurrence or metastasis. Outcomes were measured as any-cause death events and survival months after distant lymph node metastasis. A prediction model was built based on possible outcome predictors using a random survival forest algorithm and confirmed by 5×5 nested cross-validation. The effects of single variables were interpreted using partial dependence plots. A contour plot was used to visually represent survival prediction based on 2 predictive features. RESULTS: The median survival time of patients with GC with distant nodal metastasis was 9.2 months. The optimal model incorporated the prealbumin level and the prothrombin time (PT), and yielded a prediction error of 0.353. The inclusion of other variables resulted in poorer model performance. Patients with higher serum prealbumin levels or shorter PTs had a significantly better prognosis. The predicted one-year survival rate was stratified and illustrated as a contour plot based on the combined effect the prealbumin level and the PT. CONCLUSIONS: Machine learning is useful for identifying the important determinants of cancer survival using high-dimensional datasets. The prealbumin level and the PT on distant lymph node metastasis are the 2 most crucial factors in predicting the subsequent survival time of advanced GC. TRIAL REGISTRATION: ChiCTR Identifier: ChiCTR1800019978.
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BACKGROUND: Survival times differ among patients with advanced gastric carcinoma. A precise and universal prognostic evaluation strategy has not yet been established. The current study aimed to construct a prognostic scoring model for mortality risk stratification in patients with advanced gastric carcinoma. METHODS: Patients with advanced gastric carcinoma from two hospitals (development and validation cohort) were included. Cox proportional hazards regression analysis was conducted to identify independent risk factors for survival. A prognostic nomogram model was developed using R statistics and validated both in bootstrap and external cohort. The concordance index and calibration curves were plotted to determine the discrimination and calibration of the model, respectively. The nomogram score and a simplified scoring system were developed to stratify patients in the two cohorts. RESULTS: Development and validation cohort was comprised of 401 and 214 gastric cancer patients, respectively. Mucinous or non-mucinous histology, ECOG score, bone metastasis, ascites, hemoglobin concentration, serum albumin level, lactate dehydrogenase level, carcinoembryonic antigen level, and chemotherapy were finally incorporated into prognostic nomogram. The concordance indices were 0.689 (95% CI: 0.664 ~ 0.714) and 0.673 (95% CI: 0.632 ~ 0.714) for bootstrap and external validation. 100 and 200 were set as the cut-off values of nomogram score, patients in development cohort were stratified into low-, intermediate- and high-risk groups with median overall survival time 15.8 (95% CI: 12.2 ~ 19.5), 8.4 (95% CI: 6.7 ~ 10.2), and 3.9 (95% CI: 2.7 ~ 5.2) months, respectively; the cut-off values also worked well in validation cohort with different survival time in subgroups. A simplified model was also established and showed good consistency with the nomogram scoring model in both of development and validation cohorts. CONCLUSION: The prognostic scoring model and its simplified surrogate can be used as tools for mortality risk stratification in patients with advanced gastric carcinoma.
Subject(s)
Neoplasm Recurrence, Local , Nomograms , Stomach Neoplasms , Aged , Female , Humans , Male , Middle Aged , Neoplasm Metastasis/diagnosis , Neoplasm Recurrence, Local/diagnosis , Neoplasm Recurrence, Local/mortality , Neoplasm Recurrence, Local/pathology , Retrospective Studies , Risk Assessment , Stomach Neoplasms/diagnosis , Stomach Neoplasms/mortality , Stomach Neoplasms/pathologyABSTRACT
PURPOSE: While several prognostic models for the stratification of death risk have been developed for patients with advanced gastric cancer receiving first-line chemotherapy, they have seldom been tested in the Chinese population. This study investigated the performance of these models and identified the optimal tools for Chinese patients. MATERIALS AND METHODS: Patients diagnosed with metastatic or recurrent gastric adenocarcinoma who received first-line chemotherapy were eligible for inclusion in the validation cohort. Their clinical data and survival outcomes were retrieved and documented. Time-dependent receiver operating characteristic (ROC) and calibration curves were used to evaluate the predictive ability of the models. Kaplan-Meier curves were plotted for patients in different risk groups divided by 7 published stratification tools. Log-rank tests with pairwise comparisons were used to compare survival differences. RESULTS: The analysis included a total of 346 patients with metastatic or recurrent disease. The median overall survival time was 11.9 months. The patients were different into different risk groups according to the prognostic stratification models, which showed variability in distinguishing mortality risk in these patients. The model proposed by Kim et al. showed relative higher predicting abilities compared to the other models, with the highest χ2 (25.8) value in log-rank tests across subgroups, and areas under the curve values at 6, 12, and 24 months of 0.65 (95% confidence interval [CI]: 0.59-0.72), 0.60 (0.54-0.65), and 0.63 (0.56-0.69), respectively. CONCLUSIONS: Among existing prognostic tools, the models constructed by Kim et al., which incorporated performance status score, neutrophil-to-lymphocyte ratio, alkaline phosphatase, albumin, and tumor differentiation, were more effective in stratifying Chinese patients with gastric cancer receiving first-line chemotherapy.
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BACKGROUND: To evaluate whether the addition of taxanes to platinum and fluoropyrimidines in adjuvant chemotherapy would result in longer survival than platinum plus fluoropyrimidines in gastric cancer patients who received D2 gastrectomy. METHODS: Data of patients with gastric adenocarcinoma who received D2 gastrectomy and adjuvant chemotherapy with platinum plus fluoropyrimidines or taxanes, platinum plus fluoropyrimidines was retrospectively collected and analyzed. 1:1 Propensity score matching analysis was used to balance baseline characteristics between two groups. Survival curves were estimated using Kaplan-Meier method, and the differences were compared using the log-rank test. RESULTS: Four hundred twenty-five patients in the platinum plus fluoropyrimidines group and 177 patients in the taxanes, platinum plus fluoropyrimidines group were included into analysis. No statistical differences in disease-free survival and overall survival were observed between two groups. After propensity score matching, 172 couples of patients were matched, the baseline characteristics were balanced. The median disease-free survival were 15.8 months (95% CI, 9.3~22.4) in the platinum plus fluoropyrimidines group and 22.6 months (95% CI, 15.9~29.4) in the taxanes, platinum plus fluoropyrimidines group (HR = 0.63; 95% CI, 0.48~0.85; P = 0.002). The median overall survival was 25.4 months for patients in the platinum plus fluoropyrimidines group (95% CI, 19.4~31.3) and 33.8 months (95% CI, 23.5~44.2) for those in the taxanes, platinum plus fluoropyrimidines group (HR = 0.68; 95% CI, 0.53-0.87; log-rank test, P = 0.002). CONCLUSIONS: For gastric adenocarcinoma patients, the adjuvant triplet combination of taxanes, platinum, and fluoropyrimidines regimen after D2 gastrectomy was superior to platinum plus fluoropyrimidines regimen in disease-free survival as well as overall survival. TRIAL REGISTRATION: This project has been registered in the Chinese Clinical Trial Registry ( ChiCTR1800019978 ).
Subject(s)
Platinum , Stomach Neoplasms , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Chemotherapy, Adjuvant , Gastrectomy , Humans , Neoplasm Staging , Prognosis , Propensity Score , Retrospective Studies , Stomach Neoplasms/drug therapy , Stomach Neoplasms/pathology , Stomach Neoplasms/surgery , Taxoids/therapeutic useABSTRACT
The Cys2His2 (C2H2)-type zinc-finger protein (ZFP) family, which includes 176 members in Arabidopsis thaliana, is one of the largest families of putative transcription factors in plants. Of the Arabidopsis ZFP members, only 33 members are conserved in other eukaryotes, with 143 considered to be plant specific. C2H2-type ZFPs have been extensively studied and have been shown to play important roles in plant development and environmental stress responses by transcriptional regulation. The ethylene-responsive element binding-factor-associated amphiphilic repression (EAR) domain (GCC box) has been found to have a critical role in the tolerance response to abiotic stress. Many of the plant ZFPs containing the EAR domain, such as AZF1/2/3, ZAT7, ZAT10, and ZAT12, have been shown to function as transcriptional repressors. In this review, we mainly focus on the C1-2i subclass of C2H2 ZFPs and summarize the latest research into their roles in various stress responses. The role of C2H2-type ZFPs in response to the abiotic and biotic stress signaling network is not well explained, and amongst them, C1-2i is one of the better-characterized classifications in response to environmental stresses. These studies of the C1-2i subclass ought to furnish the basis for future studies to discover the pathways and receptors concerned in stress defense. Research has implied possible protein-protein interactions between members of C1-2i under various stresses, for which we have proposed a hypothetical model.
Subject(s)
Arabidopsis Proteins/physiology , Arabidopsis/genetics , Transcription Factors/physiology , Arabidopsis/metabolism , Arabidopsis Proteins/chemistry , Arabidopsis Proteins/genetics , Arabidopsis Proteins/metabolism , Stress, Physiological , Transcription Factors/chemistry , Transcription Factors/genetics , Transcription Factors/metabolism , Zinc FingersABSTRACT
This review archives the achievements made in the last two decades and presents a brief outline of some significant factors influencing the Agrobacterium-mediated transformation of Sorghum bicolor. Recently, progress in successful transformation has been made for this particular monocot crop through direct DNA delivery method and indirect method via Agrobacterium. However, lower transformation rate still proved to be a bottleneck in genetic modification of sorghum. An efficient Agrobacterium transformation system could be attained by optimizing the preliminary assays, comprising of explant source, growth media, antibiotics, Agrobacterium strains and agro-infection response of callus. The selection of competent strains for genetic transformation is also one of the key factors of consideration. Successful transformation is highly dependent on genome configuration of selected cultivar, where non-tannin genotype proved the best suited. Immature embryos from the field source have higher inherent adaptation chances than that of the greenhouse source. A higher concentration of Agrobacterium may damage the explant source. Utilization of anti-necrotic treatments and optimized tissue culture timeframe are the adequate strategies to lower down the effect of phenolic compounds. Appropriate selection of culture media vessels at different stages of tissue culture may also assist in a constructive manner. In conclusion, some aspects such as culture environment with medium composition, explant sources, and genotypes play an indispensable role in successful Agrobacterium-mediated sorghum transformation system.
Subject(s)
Agrobacterium tumefaciens/genetics , Phenols/metabolism , Sorghum/metabolism , Sorghum/microbiology , Transformation, Genetic/genetics , Sorghum/genetics , Tissue Culture Techniques/methodsABSTRACT
BACKGROUND: Pharmacological treatment of geriatric depression is often ineffective because patients cannot tolerate adequate doses of antidepressant medications. AIM: Examine the efficacy and safety of shuganjieyu - the first Chinese herbal medicine approved for the treatment of depression by China's drug regulatory agency -- with and without adjunctive treatment with repetitive transcranial magnetic stimulation (rTMS) in the treatment of geriatric depression. METHODS: Sixty-five inpatients 60 or older who met ICD-10 criteria for depression were randomly assigned to an experimental group (shuganjieyu + rTMS) (n=36) or a control group (shuganjieyu + sham rTMS)(n=29). All participants received 4 capsules of shuganjieyu daily for 6 weeks. rTMS (or sham rTMS) was administered 20 minutes daily, five days a week for 4 weeks. Blinded raters used the Hamilton Rating Scale for Depression (HAMD-17) and the Treatment Emergent Symptom Scale to assess clinical efficacy and safety at baseline and 1, 2, 4, and 6 weeks after starting treatment. Over the six-week trial, there was only one dropout from the experimental group and two dropouts from the control group. RESULTS: None of the patients had serious side effects, but 40% in the experimental group and 50% in the control group experienced minor side effects that all resolved spontaneously. Both groups showed substantial stepwise improvement in depressive symptoms over the 6 weeks. Repeated measures ANOVA found no differences between the two groups. After 6 weeks, 97% of the experimental group had experienced a 25% or greater drop in the level of depression, but only 20% had experience a 50% or greater drop in the level of depression; the corresponding values in the control group were 96% and 19%. There were some minor, non-significant differences in the onset of the treatment effect between the different types of depressive symptoms, but by the second week of treatment all five HAMD-17 subscale scores had improved significantly in both groups. CONCLUSION: The Chinese herbal medicine shuganjieyu is effective and safe in the treatment of geriatric depression, but only a minority of patients have greater than 50% improvement in their depressive symptoms after 6 weeks of treatment. Adjunctive use of rTMS with shuganjieyu does not improve the overall outcome and does not significantly speed up the onset of action of shuganjieyu.
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WNK (with no lysine [K]) kinases play important regulatory roles in flowering, as well as salt and osmotic stress tolerance in plants. Here, we report that AtWNK9, a member of the Arabidopsis WNK gene family, was induced by exogenous abscisic acid (ABA) treatment and dehydration stress. Overexpression of AtWNK9 from the cauliflower mosaic virus 35S promoter in Arabidopsis resulted in increased sensitivity to ABA, strong inhibition of primary root elongation, increased proline accumulation, reduced stomatal aperture, and a reduced rate of water loss. In addition, plant survival under drought stress was improved compared to wild type. In contrast, a mutant with a T-DNA insertion in AtWNK9 showed reduced ABA sensitivity and an increased rate of water loss; further, it showed increased susceptibility to drought stress. The transcription of a number of ABA signaling components, including ABI1, ERA1, ABI3, and ABF3, was up-regulated in AtWNK9 transgenic plants and down-regulated in the wnk9 mutant in response to ABA. Some ABA-responsive and biosynthetic genes, as well as other drought-related genes, were altered at various levels in AtWNK9 transgenic plants and wnk9 mutants under dehydration stress. Overall, these findings suggest that AtWNK9 plays a positive role in ABA signaling and improves drought tolerance in transgenic Arabidopsis.
Subject(s)
Abscisic Acid/metabolism , Adaptation, Physiological/genetics , Arabidopsis Proteins/genetics , Arabidopsis/genetics , Droughts , Genes, Plant , Water , Abscisic Acid/pharmacology , Arabidopsis/metabolism , Arabidopsis Proteins/metabolism , DNA, Bacterial , Gene Expression , Mutagenesis, Insertional , Plants, Genetically Modified , Signal Transduction , Stress, Physiological/geneticsABSTRACT
We demonstrate a facile one-pot approach for the synthesis of reduced graphene oxide (rGO)-cuprous sulfide quantum dot (Cu2S QD) hybrids, wherein the reduction of GO and the growth of Cu2S QDs on graphene occur simultaneously. The as-synthesized rGO-Cu2S QD hybrids exhibit an excellent photoelectric response and efficient electron transfer from the Cu2S QDs to the rGO sheets.
Subject(s)
Copper/chemistry , Electronics , Graphite/chemistry , Quantum Dots/chemistry , Sulfides/chemistry , Electron Transport , Light , Oxides/chemistryABSTRACT
Plant cytochrome P450 monooxygenases (CYP) constitute a large superfamily of heme-thiolate proteins, which are involved in a wide range of metabolic pathways. In this study, comparative genomic approaches were used to analyze tobacco CYP genes and their expression patterns. Based on analysis of the tobacco genomic DNA sequences that are currently available, 263 P450 genes that belong to 44 distinct clans were identified. EST evidence from 173 of the CYPs suggested that these genes are transcribed. Sequence features and secondary structures of the tobacco P450 genes were further analyzed through comparison with known P450 proteins. The expression profiles of 73 P450 genes were subsequently investigated by analyses of tobacco microarray data and RT-PCR. The results showed a variety of expression patterns of these genes in different tissues with a number of genes expressed in a tissue-specific manner. This study has set a foundation for further studies on functions of P450 genes in tobacco.
Subject(s)
Cytochrome P-450 Enzyme System/genetics , Genomics , Nicotiana/genetics , Base Sequence , Cluster Analysis , Cytochrome P-450 Enzyme System/chemistry , Expressed Sequence Tags , Gene Expression Profiling , Gene Expression Regulation, Plant , Molecular Sequence Data , Multigene Family , Sequence AlignmentABSTRACT
The expression of FOA1 (F-box overexpressed/oppressed ABA signaling) in different organs of Arabidopsis, and in response to ABA and NaCl, was analyzed. The expression level of FOA1 is higher in the root and is lower in the stem, and is induced rapidly by ABA and NaCl. The phenotypes of T-DNA insertion mutant foa1 and FOA1 overexpression lines FOA1ox1 and FOA1ox2 were analyzed. The foa1 mutant exhibited a lower germination rate, shorter root length, more stomatal opening, increased proline accumulation and hypersensitivity to ABA compared with the wild type. In contrast, the overexpression lines showed lower sensitivity to ABA than the wild type. The expression levels of several ABA and stress-responsive transcription factors and genes were altered in the foa1 mutant in response to ABA. Compared with the wild type, the expression levels of ABA-responsive transcription factors were higher, but ABA and stress-responsive genes were lower in foa1 mutant. This study demonstrates that FOA1 is an ABA signaling-related gene, and may play a negative role in ABA signaling.