Downregulation of Ebp1Khib210 promotes keratinocyte proliferation through induction of TIF-IA-mediated rRNA synthesis.

BACKGROUND: Psoriasis is a prevalent chronic inflammatory dermatosis characterized by excessive proliferation of keratinocytes. Protein lysine 2-hydroxyisobutyrylation (Khib) is a newly identified post-translational modification that regulates various biological processes. Abnormal Khib modification has been closely associated with the development of autoimmune diseases. OBJECTIVE: To investigate the abnormal Khib profile and its pathogenic role in psoriasis. METHODS: We utilized liquid chromatography-tandem mass spectrometry to analyze Khib-modified proteins in the epidermis of psoriasis and healthy controls. Mutated cells and mice with downregulated Ebp1Khib210 were generated to investigate its functional effects in psoriasis. RESULTS: The omic analysis revealed dysregulation of Khib modification in psoriatic lesions, exhibiting a distinct profile compared to controls. We observed the downregulation of Ebp1Khib210 in psoriatic lesions and IMQ-induced psoriatic mice. Notably, the expression of Ebp1Khib210 was upregulated in psoriatic patients following effective treatment. Decreased Ebp1Khib210 enhanced keratinocyte viability, proliferation, and survival while inhibiting apoptosis in vitro. Additionally, Pa2g4K210A mice with downregulated Ebp1Khib210 exhibited more severe psoriatic lesions and enhanced keratinocyte proliferation. Moreover, we found that Ebp1K210A mutation increased the interaction between Ebp1 and nuclear Akt, thereby inhibiting MDM2-mediated TIF-IA ubiquitination, and resulting to increased rRNA synthesis and keratinocyte proliferation. The downregulation of Ebp1Khib210 was attributed to inflammation-induced increases in HDAC2 expression. CONCLUSION: Our findings demonstrate that downregulation of Ebp1Khib210 promotes keratinocyte proliferation through modulation of Akt signaling and TIF-IA-mediated rRNA synthesis. These insights into Khib modification provide a better understanding of the pathogenesis of psoriasis and suggest potential therapeutic targets.

Association of triglyceride-glucose index and neutrophil-to-lymphocyte ratio with coronary artery disease.

OBJECTIVE: The present study aimed to investigate the association of triglyceride-glucose (TyG) index and neutrophil-to-lymphocyte ratio (NLR) with coronary artery disease (CAD), and evaluate the cumulative value of TyG index and NLR in identifying CAD, as well as the severity of CAD. METHODS: This retrospective study enrolled 2867 patients who underwent coronary angiography (CAG) for the first time between January 2013 and June 2022 in Zhongnan Hospital of Wuhan University. There were 2109 patients with CAD and 758 patients without CAD. The CAD patients were divided into two groups based on the median of Gensini score (mild stenosis CAD group: Gensini score < 26 points; severe stenosis CAD group: Gensini score ≥ 26 points). To further evaluate the cumulative value of TyG index and NLR in identifying CAD and CAD severity, all patients were classified into four groups based on median of TyG index and NLR: (1) the control group: patients with low-TyG and low-NLR; (2) isolated high-NLR group: patients with low-TyG and high- NLR; (3) isolated high- TyG group: patients with high-TyG and low- NLR; (4) high-TyG combined with high-NLR group: patients with high-TyG and high- NLR. RESULTS: Multivariate logistic regression analysis showed that both the TyG index and NLR were independent risk factors for CAD, and they were also independent risk factors for severe stenosis in CAD (P < 0.05). Compared with the low-TyG and low- NLR group, patients in high-TyG and high- NLR group had a 1.418 times higher odds ratio (OR) of having CAD and a 1.692 times higher OR of having severe stenosis in CAD in the multivariable logistic regression model. It is worth noting that the OR values of the high-TyG and high- NLR group were higher than those of the isolated high-NLR group and the isolated high- TyG group. The ROC analysis showed that the combination of the TyG index and NLR was superior to TyG index or NLR in predicting CAD and CAD severity. CONCLUSION: Compared to TyG index or NLR, the combination of the TyG index and NLR is beneficial to improve the diagnostic accuracy of CAD and CAD severity.

CsBZIP40 confers resistance against citrus bacterial canker by repressing CsWRKY43-CsPrx53/CsSOD13 cascade mediated ROS scavenging.

As the bacterial etiologic agent causing citrus bacterial canker (CBC), Xanthomonas citri subsp. citri (Xcc) seriously impacts citrus plantation and fruit production globally. In an earlier study, we demonstrated that CsBZIP40 can positively impact CBC resistance in the sweet orange (Citrus sinensis). However, the mechanistic basis for the protective benefits conferred by CsBZIP40 is yet to be delineated. Here, we show that CsBZIP40 positively regulates CBC resistance and reactive oxygen species (ROS) homeostasis in transgenic sweet orange overexpressing CsBZIP40. CsBZIP40 directly binds to the TGA-box of the CsWRKY43 promoter to repress its transcriptional activity. CsWRKY43 overexpression induces CBC susceptibility in transgenic sweet oranges. In contrast, its inhibition produces strong resistance to CBC. CsWRKY43 directly binds to the W-boxes of the CsPrx53 and CsSOD13 promoters to positively regulate the activities of these antioxidant enzymes, resulting in the negative regulation of ROS homeostasis and CBC resistance in sweet orange plants. CsPrx53/CsSOD13 knockdown enhances ROS accumulation and CBC resistance. Overall, our results outline a regulatory pathway through which CsBZIP40 transcriptionally represses CsWRKY43-CsPrx53/CsSOD13 cascade-mediated ROS scavenging in a manner conducive to CBC resistance. These mechanisms underscore the potential importance of CsBZIP40, CsWRKY43, CsPrx53, and CsSOD13, providing promising strategies for the prevention of CBC.

Comparison of the value of various complex indexes of blood cell types and lipid levels in coronary heart disease.

Background: Inflammation and lipid infiltration play crucial roles in the development of atherosclerosis. This study aimed to investigate the association between various complex indexes of blood cell types and lipid levels with the severity of coronary artery stenosis and their predictive value in coronary heart disease (CHD). Methods: The retrospective study was conducted on 3,201 patients who underwent coronary angiography at the Department of Zhongnan Hospital of Wuhan University. The patients were divided into two groups: CHD group and non-CHD group. The CHD group was further classified into three subgroups (mild, moderate, severe) based on the tertiles of their Gensini score or SYNTAX score I. Various complex indexes of blood cell types and lipid levels were compared between the groups. Results: It revealed a positive correlation between all complex indexes and the severity of coronary artery stenosis. The systemic inflammation-response index/high-density lipoprotein cholesterol count (SIRI/HDL) exhibited the strongest correlation with both severity scores (Gensini score: r = 0.257, P < 0.001; SYNTAX score I: r = 0.171, P < 0.001). The monocyte to high-density lipoprotein cholesterol ratio (MHR) was identified as a stronger independent risk factor for CHD. However, SIRI/HDL had higher diagnostic efficacy for CHD (sensitivity 66.7%, specificity 60.4%, area under curve 0.680, 95% CI: 0.658-0.701). Notably, the pan-immune-inflammation value multiplied by low-density lipoprotein cholesterol count (PIV × LDL) exhibited the highest sensitivity of 85.2%. Conclusion: All complex indexes which we investigated exhibited positive correlations with the severity of coronary artery stenosis. SIRI/HDL demonstrated higher diagnostic efficiency for CHD and a significant correlation with the severity of coronary artery stenosis.

Psoriatic Dermal-Derived Mesenchymal Stem Cells Induced C3 Expression in Keratinocytes.

Purpose: Our recent studies found a splice region mutation in C3 accompanied by a significantly increased C3 in psoriatic peripheral blood. Mesenchymal stem cells (MSCs) are a key immunological suppression cell. We further investigate the regulation of MSCs on C3 in psoriasis. Patients and Methods: We analyzed the C3 and its upstream S100A9, S100A8 and downstream MCP1 in psoriatic and control skin, and in normal human epidermal keratinocytes (NHEKs) co-cultured with psoriatic versus control dermal-derived mesenchymal stem cells (DMSCs) by mRNA, iTRAQ (isobaric tags for relative and absolute quantitative) and simple Western analysis. Results: The mRNA and Simple Western analysis showed that the expression of C3, S100A8 and S100A9 are upregulated in psoriatic lesion (C3: mRNA, 9.23-fold, p = 0.0092; protein, 3.56-fold, p = 0.0244. S100A8: mRNA, 28.35-fold, p = 0.0015; protein, 4.68-fold, p = 0.0215. S100A9: mRNA, 79.45-fold, p = 0.0066; protein, 12.42-fold, p > 0.05). Moreover, the iTRAQ showed that C3 and S100A9 were significantly increased in NHEKs after co-cultured with psoriatic DMSCs compared to that of control DMSCs (C3: 3.40-fold, p = 0, FDR = 0; S100A9: 2.30-fold, p = 9.86E-241, FDR = 6.50E-239), verified by Simple Western. However, the expression of S100A8 and MCP1 was slightly different between the two groups. Conclusion: Our results suggest that psoriatic DMSCs contribute to the increased C3 expression in psoriatic lesion via upregulating S100A9, providing the theoretical basis for the role of C3 and DMSCs in the pathogenesis of psoriasis.

Dermal Mesenchymal Stem Cells from Psoriatic Lesions Stimulate HaCaT Cell Proliferation, Differentiation, and Migration via Activating the PI3K/AKT Signaling Pathway.

BACKGROUND: Psoriasis is a chronic inflammatory skin disease characterized by excessive proliferation and abnormal differentiation of keratinocytes. Dermal mesenchymal stem cells (DMSCs) are not only involved in the regeneration of skin tissue, but also can regulate skin microenvironment by secreting cytokines. However, whether and how psoriatic DMSCs regulate proliferation and differentiation of keratinocytes remains unknown. OBJECTIVE: To study the effects of psoriatic DMSCs on the proliferation, differentiation, and migration of keratinocytes and the underlying mechanisms. METHODS: Following co-cultures of HaCaT cells with either psoriatic DMSCs (p-DMSCs) or DMSCs from normal volunteers (n-DMSCs), HaCaT cell proliferation was assessed using CCK-8 and EDU incorporation assay, while scratch assay and transwell assay were used to assess cell migration. qRT-PCR was used to determine expression levels of mRNA for cell proliferation (Ki-67) and differentiation (keratin 5, involucrin, and filaggrin). Western blot was used to measure expression levels of proteins associated with keratinocyte proliferation and differentiation in cultured HaCaT cells treated with or without PI3K inhibitor. ELISA assay was used to measure expression profile of stem cell factor (SCF), epidermal growth factor (EGF), and interleukin-11 (IL-11) within the co-culture supernatants. RESULTS: The results showed that p-DMSCs displayed a higher potency than n-DMSCs in stimulating proliferation, differentiation, and migration of HaCaT cells. Expression levels of PI3K and AKT proteins were markedly increased in HaCaT cells co-cultured with DMSCs versus HaCaT cell culture alone. Moreover, inhibition of the PI3K/AKT signaling pathway reversed the effect of p-DMSCs on proliferation, differentiation, and migration of HaCaT cells. Compared with n-DMSCs, the p-DMSCs showed increased secretion of IL-11, EGF, and SCF. CONCLUSION: p-DMSCs stimulate HaCaT cell proliferation, differentiation and migration via activating the PI3K/AKT signaling pathway, providing a new insight into the pathogenesis of psoriasis.

Pyramiding the antimicrobial PR1aCB and AATCB genes in 'Tarocco' blood orange (Citrus sinensis Osbeck) to enhance citrus canker resistance.

Citrus canker, caused by Xanthomonas citri subsp. citri (Xcc), is a major bacterial disease responsible for substantial economic losses in citrus-producing areas. To breed transgenic citrus plants with enhanced resistance to citrus canker, two antimicrobial peptide genes, PR1aCB and AATCB, were incorporated into 'Tarocco' blood orange (Citrus sinensis Osbeck) plants via co-transformation and sequential re-transformation. The presence of PR1aCB and AATCB in double transgenic plants was confirmed by PCR. The expression of PR1aCB and AATCB in double transformants was demonstrated by quantitative real-time PCR. An in vivo disease resistance assay involving the injection of Xcc revealed that the double transformants were more resistant to citrus canker than the single gene transformants and wild-type plants. An analysis of the bacterial population indicated that the enhanced citrus canker resistance of the double transformants was due to inhibited Xcc growth. These results proved that the pyramiding of multiple genes is a more effective strategy for increasing the disease resistance of transgenic citrus plants than single gene transformations.

Overexpression of Salicylic Acid Carboxyl Methyltransferase (CsSAMT1) Enhances Tolerance to Huanglongbing Disease in Wanjincheng Orange (Citrus sinensis (L.) Osbeck).

Citrus Huanglongbing (HLB) disease or citrus greening is caused by Candidatus Liberibacter asiaticus (Las) and is the most devastating disease in the global citrus industry. Salicylic acid (SA) plays a central role in regulating plant defenses against pathogenic attack. SA methyltransferase (SAMT) modulates SA homeostasis by converting SA to methyl salicylate (MeSA). Here, we report on the functions of the citrus SAMT (CsSAMT1) gene from HLB-susceptible Wanjincheng orange (Citrus sinensis (L.) Osbeck) in plant defenses against Las infection. The CsSAMT1 cDNA was expressed in yeast. Using in vitro enzyme assays, yeast expressing CsSAMT1 was confirmed to specifically catalyze the formation of MeSA using SA as a substrate. Transgenic Wanjincheng orange plants overexpressing CsSAMT1 had significantly increased levels of SA and MeSA compared to wild-type controls. HLB resistance was evaluated for two years and showed that transgenic plants displayed significantly alleviated symptoms including a lack of chlorosis, low bacterial counts, reduced hyperplasia of the phloem cells, and lower levels of starch and callose compared to wild-type plants. These data confirmed that CsSAMT1 overexpression confers an enhanced tolerance to Las in citrus fruits. RNA-seq analysis revealed that CsSAMT1 overexpression significantly upregulated the citrus defense response by enhancing the transcription of disease resistance genes. This study provides insight for improving host resistance to HLB by manipulation of SA signaling in citrus fruits.

CsLOB1 regulates susceptibility to citrus canker through promoting cell proliferation in citrus.

Citrus sinensis lateral organ boundary 1 (CsLOB1) was previously identified as a critical disease susceptibility gene for citrus bacterial canker, which is caused by Xanthomonas citri subsp. citri (Xcc). However, the molecular mechanisms of CsLOB1 in citrus response to Xcc are still elusive. Here, we constructed transgenic plants overexpressing and RNAi-silencing of CsLOB1 using the canker-disease susceptible 'wanjincheng' orange (C. sinensis Osbeck) as explants. CsLOB1-overexpressing plants exhibited dwarf phenotypes with smaller and thicker leaf, increased branches and adventitious buds clustered on stems. These phenotypes were followed by a process of pustule- and canker-like development that exhibited enhanced cell proliferation. Pectin depolymerization and expansin accumulation were enhanced by CsLOB1 overexpression, while cellulose and hemicellulose synthesis were increased by CsLOB1 silence. Whilst overexpression of CsLOB1 increased susceptibility, RNAi-silencing of CsLOB1 enhanced resistance to canker disease without impairing pathogen entry. Transcriptome analysis revealed that CsLOB1 positively regulated cell wall degradation and modification processes, cytokinin metabolism, and cell division. Additionally, 565 CsLOB1-targeted genes were identified in chromatin immunoprecipitation-sequencing (ChIP-seq) experiments. Motif discovery analysis revealed that the most highly overrepresented binding sites had a conserved 6-bp 'GCGGCG' consensus DNA motif. RNA-seq and ChIP-seq data suggested that CsLOB1 directly activates the expression of four genes involved in cell wall remodeling, and three genes that participate in cytokinin and brassinosteroid hormone pathways. Our findings indicate that CsLOB1 promotes cell proliferation by mechanisms depending on cell wall remodeling and phytohormone signaling, which may be critical to citrus canker development and bacterial growth in citrus.

Overexpressing a NPR1-like gene from Citrus paradisi enhanced Huanglongbing resistance in C. sinensis.

KEY MESSAGE: Overexpression of CiNPR4 enhanced resistance of transgenic citrus plants to Huanglongbing by perceiving the salicylic acid and jasmonic acid signals and up-regulating the transcriptional activities of plant-pathogen interaction genes. Developing transgenic citrus plants with enhanced immunity is an efficient strategy to control citrus Huanglongbing (HLB). Here, a nonexpressor of pathogenesis-related gene 1 (NPR1) like gene from HLB-tolerant 'Jackson' grapefruit (Citrus paradisi Macf.), CiNPR4, was introduced into 'Wanjincheng' orange (Citrus sinensis Obseck). CiNPR4 expression was determined in transgenic citrus plants using quantitative real-time PCR analyses. The Candidatus Liberibacter asiaticus (CLas) pathogen of HLB was successfully transmitted to transgenic citrus plants by grafting infected buds. HLB symptoms developed in transgenic and wild-type (WT) plants by 9 months after inoculation. A CLas population analysis showed that 26.9% of transgenic lines exhibited significantly lower CLas titer levels compared with the CLas-infected WT plants at 21 months after inoculation. Lower starch contents and anatomical aberration levels in the phloem were observed in transgenic lines having enhanced resistance compared with CLas-infected WT plants. CiNPR4 overexpression changed the jasmonic acid, but not salicylic acid, level. Additionally, the jasmonic acid and salicylic acid levels increased after CLas infection. Transcriptome analyses revealed that the enhanced resistance of transgenic plants to HLB resulted from the up-regulated transcriptional activities of plant-pathogen interaction-related genes.

The regulation of dermal mesenchymal stem cells on keratinocytes apoptosis.

Dermal mesenchymal stem cells (DMSCs) are progenitor cells with the capacity of self-renewal, multilineage differentiation, and immunomodulation, which were reported to induce the proliferation of keratinocytes, however the regulation on keratinocytes apoptosis was unknown. In this study, we isolated DMSCs from normal skin and co-cultured with keratinocytes, and then detected apoptosis of keratinocytes by flow cytometry and expression of apoptosis associated proteins by western blot. The mRNA expression profile of normal DMSCs was investigated by RNA sequencing. The results of our study presented that the DMSCs promoted HaCaT cells apoptosis both in early apoptotic state (13.8 vs. 2.9, p < 0.05) and late apoptotic state (4.2 vs. 0.7, p < 0.05). The expression of apoptosis associated proteins caspase-3 (3.51 vs. 1.99, p < 0.05) and lymphoid enhancer-binding factor 1 (3.10 vs. 0.83, p < 0.05) were upregulated. However, the cell cycle protein cyclin E1 was similar (9.38 vs. 9.05, p > 0.05). Moreover, 33 genes with the function of induced cell apoptosis were highly expressed in DMSCs, including insulin-like growth factor-binding protein 4 (2828.13), IGFBP7 (1805.69), cathepsin D (1694.34), cathepsin B (CTSB, 1641.40) and dickkopf WNT signaling pathway inhibitor 1 (DKK1, 384.79). This study suggested DMSCs induce the apoptosis of keratinocytes through non-G1/S phase blockade via highly expression of apoptosis inducer.

A novel near-infrared light-responsive photoelectrochemical platform for detecting microcystin-LR in fish based on Ag2S cubes and plasmonic Au nanoparticles.

As a main contaminant in fish, microcystin-LR (MC-LR) leads to serious liver problems; therefore, the development of MC-LR sensors is important to guarantee aquatic food safety. In this work, a near-infrared (NIR) light-excited photoelectrochemical (PEC) immunosensor was developed through conjugation of Ag2S cubes with Au nanoparticles (NPs) to determine MC-LR residues in fish. Specifically, as a narrow-band semiconducting material, Ag2S is capable of absorbing NIR light. Taking advantage of the localized surface plasmon resonance (LSPR) effect along with good conductivity of AuNPs, the developed AuNP/Ag2S/fluorine-doped tin oxide (FTO) owns much higher photoelectric conversion efficiency, and the photocurrent is 5.3 times that of Ag2S FTO. Subsequently, the NIR-driven AuNP/Ag2S/FTO was used to immobilize antibodies (Abs) for MC-LR. Their specificity to MC-LR led to steric effects and limited surface electron transfer, causing reduce of the photocurrent. Through AuNP/Ag2S-composite amplification and immunological specificity, the PEC immunosensor can quantitatively measure MC-LR with a wide linear range, 10 pg L-1 to 10 µg L-1, and a much low detection limit, 7 pg L-1 (S/N = 3). Finally, the NIR PEC sensor was employed in the analysis of MC-LR contents in fish. This work reveals the NIR-responsive ability of Ag2S cubes and deepens understanding the role of AuNPs in the PEC process. Due to the superior properties, the developed NIR PEC immunosensor has been demonstrated as a promising method for analysis of biological samples.

Rapid extraction of domoic acid by a magnetic molecularly imprinted silica before HPLC measurement.

A magnetic molecularly imprinted silica solid was obtained by sol-gel polymerization for the separation of domoic acid. The solid showed rapid adsorption kinetics with an adsorption equilibrium time of 5 min. The solid showed affinity to domoic acid under the interference of tryptophan and could be repeatedly used for 5 times at least. The solid was used as a solid-phase-extraction sorbent for the extraction of domoic acid from clam samples before measurement with liquid chromatography. The detection limit of 0.20 mg kg-1 was lower than the allowable limits in several countries or areas. The recoveries in the spiked samples were 88% approximately.

Hexokinase II Inhibitory Effect of Secondary Metabolites Derived from a Streptomyces sp. Associated with Mud Dauber Wasp.

Insect-microbial symbioses have vast biochemical diversity, which is beneficial to produce bioactive secondary metabolites. In this study, chemical examination of a Streptomyces sp. associated with a mud dauber wasp led to the isolation of fourteen compounds. Their structures were determined by spectroscopic methods and comparison with literature data. Among the isolates, compounds 1,2,3-benzotriazin-4(1H)-one and 4-(2-aminoethyl)phenyl acetate were first reported from this species. Bioactivities of the isolated compounds were assayed for the first time against hexokinase II. 4-(2-Aminoethyl)phenyl acetate, germicidin B, phenylacetic acid, isogermicidin A and germicidin C displayed significant inhibitory activity against hexokinase II, with the IC50 values of 5.11, 7.11, 7.15, 8.45 and 8.78 µM, respectively.

Molecularly imprinted polymer-based photonic crystal sensor array for the discrimination of sulfonamides.

In this paper, molecular imprinting and photonic crystal techniques were combined to construct a four-channel sensor array for the simultaneous identification of various sulfonamides. The assay was composed of four units. Three of these units were prepared using sulfaguanidine, sulfamethazine, or sulfathiazole as template molecules. The fourth unit was prepared without a template molecule. The preparation was optimized to obtain maximum identification with a molar ratio of template, monomer, and cross-linker of 1:50:10. The response time was as short as 10 min. For demonstration, six sulfonamides were selected as analytes. The Bragg diffraction patterns of analytes at different concentrations were measured using the sensor array. Data obtained were analyzed using linear discrimination analysis (LDA) and principal component analysis (PCA). LDA can be applied for SAs discrimination. The message ratios of 87.6%, 94.4%, and 95.8% for six SAs at 10-4 mol L-1, 10-6 mol L-1, and 10-8 mol L-1 were achieved using LDA. The sensor array identified the mixture containing various SAs with an LDA coefficient of 86.1%, thereby indicating that the sensor array had a strong anti-interference ability. The sensor array was used to identify six SAs in fish samples. The measured data in spiked samples were consistent with the fingerprint collected from standard solutions. The accuracy rate reached 90.9%, indicating that the array can be used to identify SAs from food samples.

CitGVD: a comprehensive database of citrus genomic variations.

Citrus is one of the most important commercial fruit crops worldwide. With the vast genomic data currently available for citrus fruit, genetic relationships, and molecular markers can be assessed for the development of molecular breeding and genomic selection strategies. In this study, to permit the ease of access to these data, a web-based database, the citrus genomic variation database (CitGVD, http://citgvd.cric.cn/home) was developed as the first citrus-specific comprehensive database dedicated to genome-wide variations including single nucleotide polymorphisms (SNPs) and insertions/deletions (INDELs). The current version (V1.0.0) of CitGVD is an open-access resource centered on 1,493,258,964 high-quality genomic variations and 84 phenotypes of 346 organisms curated from in-house projects and public resources. CitGVD integrates closely related information on genomic variation annotations, related gene annotations, and details regarding the organisms, incorporating a variety of built-in tools for data accession and analysis. As an example, CitGWAS can be used for genome-wide association studies (GWASs) with SNPs and phenotypic data, while CitEVOL can be used for genetic structure analysis. These features make CitGVD a comprehensive web portal and bioinformatics platform for citrus-related studies. It also provides a model for analyzing genome-wide variations for a wide range of crop varieties.

Overexpressing GH3.1 and GH3.1L reduces susceptibility to Xanthomonas citri subsp. citri by repressing auxin signaling in citrus (Citrus sinensis Osbeck).

The auxin early response gene Gretchen Hagen3 (GH3) plays dual roles in plant development and responses to biotic or abiotic stress. It functions in regulating hormone homeostasis through the conjugation of free auxin to amino acids. In citrus, GH3.1 and GH3.1L play important roles in responding to Xanthomonas citri subsp. citri (Xcc). Here, in Wanjingcheng orange (Citrus sinensis Osbeck), the overexpression of CsGH3.1 and CsGH3.1L caused increased branching and drooping dwarfism, as well as smaller, thinner and upward curling leaves compared with wild-type. Hormone determinations showed that overexpressing CsGH3.1 and CsGH3.1L decreased the free auxin contents and accelerated the Xcc-induced decline of free auxin levels in transgenic plants. A resistance analysis showed that transgenic plants had reduced susceptibility to citrus canker, and a transcriptomic analysis revealed that hormone signal transduction-related pathways were significantly affected by the overexpression of CsGH3.1 and CsGH3.1L. A MapMan analysis further showed that overexpressing either of these two genes significantly downregulated the expression levels of the annotated auxin/indole-3-acetic acid family genes and significantly upregulated biotic stress-related functions and pathways. Salicylic acid, jasmonic acid, abscisic acid, ethylene and zeatin levels in transgenic plants displayed obvious changes compared with wild-type. In particular, the salicylic acid and ethylene levels involved in plant resistance responses markedly increased in transgenic plants. Thus, the overexpression of CsGH3.1 and CsGH3.1L reduces plant susceptibility to citrus canker by repressing auxin signaling and enhancing defense responses. Our study demonstrates auxin homeostasis' potential in engineering disease resistance in citrus.

Cytotoxic, Anti-Migration, and Anti-Invasion Activities on Breast Cancer Cells of Angucycline Glycosides Isolated from a Marine-Derived Streptomyces sp.

Four angucycline glycosides were previously characterized from marine-derived Streptomyces sp. OC1610.4. Further investigation of this strain cultured on different fermentation media from that used previously resulted in the isolation of two new angucycline glycosides, vineomycins E and F (1-2), and five known homologues, grincamycin L (3), vineomycinone B2 (4), fridamycin D (5), moromycin B (7), and saquayamycin B1 (8). Vineomycin F (2) contains an unusual ring-cleavage deoxy sugar. All the angucycline glycosides isolated from Streptomyces sp. OC1610.4 were evaluated for their cytotoxic activity against breast cancer cells MCF-7, MDA-MB-231, and BT-474. Moromycin B (7), saquayamycin B1 (8), and saquayamycin B (9) displayed potent anti-proliferation against the tested cell lines, with IC50 values ranging from 0.16 to 0.67 µM. Saquayamycin B (9) inhibited the migration and invasion of MDA-MB-231 cells in a dose-dependent manner, as detected by Transwell and wound-healing assays.

Strepantibins A-C: Hexokinase II Inhibitors from a Mud Dauber Wasp Associated Streptomyces sp.

Two new p-terphenyls, strepantibins A and B (1 and 2), along with the first representative of a naturally occurring bisphenyltropone, strepantibin C (3), were characterized from a Streptomyces sp. associated with the larvae of the mud dauber wasp Sceliphron madraspatanum. Their structures were determined by high-resolution electrospray ionization mass spectrometry, NMR, and X-ray crystallography data interpretation. Strepantibins A-C inhibited hexokinase II (HK2) activity and displayed antiproliferative activity against hepatoma carcinoma cells HepG-2, SMMC-7721 and plc-prf-5. In SMMC-7721 cells treated with strepantibin A, the morphological characteristics of apoptosis were observed.

Functional analysis of citrus AP2 transcription factors identified CsAP2-09 involved in citrus canker disease response and tolerance.

Genetic engineering approaches offer an alternative method to the citrus canker resistance breeding. The ethylene response factor (ERF) family is a member of families of transcription factors that are particular to plants and contribute significantly to biotic stress response and to plant growth. CsAP2-09 belongs to the citrus AP2/ERF transcription factor family. Initially, we proved the induction of CsAP2-09 in wild-types by Xcc and some hormones involved in pathogen response. We successfully cloned the CsAP2-09 and proved that CsAP2-09 protein is targeted to the nucleus. The CsAP2-09 was functionally characterized with over-expression and RNAi silencing strategy. In the overexpression lines, the diseased lesions and disease index were significantly decreased while in RNAi lines of CsAP2-09 the diseased lesions and disease index were significantly enhanced. Thus, the over-expression conferred Xcc resistance to transgenic citrus while silencing of CsAP2-09 in sweet orange leads to Xcc susceptibility. When the transcriptomes of WT and overexpression transcriptomes were compared, they revealed that some genes involved in phenylpropanoid biosynthesis, pathogen responses, transcript regulation etc. were modified. Our results provide a possibility for improving citrus canker disease resistance by over-expression of CsAP2s. Furthermore, various functions of CsAP2-09 provide significant information about the role of AP2/ERFs in plant disease resistance and stress tolerance.