Homeostatic control of polyamine levels under long-term salt stress in Arabidopsis

Salt stress has been frequently studied in its first osmotic phase. Very often, data regarding the second ionic phase is missing. It has also been suggested that Putrescine or/and Spermine could be responsible for salt resistance. In order to test this hypothesis under long-term salt stress, we obtained Arabidopsis thaliana transgenic plants harboring pRD29A::oatADC or pRD29A::GUS construction. Although Putrescine was the only polyamine significantly increased after salt acclimation in pRD29A::oatADC transgenic lines, this rendered in no advantage to this kind of stress. The higher Spermine levels found in WT and transgenic lines when compared to control conditions along with no increment on Putrescine levels in WT plants under salt acclimation, leads us to analyze Spermine effect on pADC1 and pADC2 expression. Increasing levels of this polyamine inhibits these promoters expression while enhances pRD29A expression, making Spermine the polyamine responsible for salt acclimation, and the transgenic lines developed in this work suitable for studying Putrescine roles in conditions where its biosynthesis would be inhibited in the WT genotype

The receptor kinase SRF3 coordinates iron- level and flagellin dependent defense and growth responses in plants

Iron is critical for host–pathogen interactions. While pathogens seek to scavenge iron to spread, the host aims at decreasing iron availability to reduce pathogen virulence. Thus, iron sensing and homeostasis are of particular importance to prevent host infection and part of nutritional immunity. While the link between iron homeostasis and immunity pathways is well established in plants, how iron levels are sensed and integrated with immune response pathways remains unknown. Here we report a receptor kinase SRF3, with a role in coordinating root growth, iron homeostasis and immunity pathways via regulation of callose synthases. These processes are modulated by iron levels and rely on SRF3 extracellular and kinase domains which tune its accumulation and partitioning at the cell surface. Mimicking bacterial elicitation with the flagellin peptide flg22 phenocopies SRF3 regulation upon low iron levels and subsequent SRF3-dependent responses. We propose that SRF3 is part of nutritional immunity responses involved in sensing external iron levels

Plant polyamines in stress and development

Polyamines are small aliphatic polycations which have been involved in key stress and developmental processes in plants. In the recent years, compelling genetic and molecular evidences point to polyamines as essential metabolites required for resistance to drought, freezing, salinity, oxidative stress among other type of abiotic and biotic stresses. In addition to their role as stress-protective compounds, polyamines participate in key developmental processes mediated by specific signaling pathways or in cross-regulation with other plant hormones. Our Research Topic aims to integrate the multiple stress and developmental regulatory functions of polyamines in plants under a genetic, molecular and evolutionary perspective with special focus on signaling networks, mechanisms of action and metabolism regulation

Late-Stage C(sp2)–C(sp3) Diversification via Nickel Oxidative Addition Complexes

Nickel catalysis has emerged as a powerful technique for streamlining the access to exceedingly complex organic molecules from simple precursors. However, nickel-catalyzed cross-couplings with advanced synthetic intermediates still remain a considerable challenge. Herein, we describe a technique based on the utilization of nickel oxidative addition complexes (Ni-OAC) of drug-like molecules as a platform to rapidly and reliably generate lead candidates with enhanced C(sp3) fraction. The potential of Ni-OACs to access new chemical space has been assessed in three different C(sp2)–C(sp3) bond-forming events without recourse to specialized ligand backbones. Reactions with Ni-OACs proceed under exceptionally mild conditions and with improved generality when compared to nickel-catalyzed reactions. The development of an automated process for forging C(sp2)–C(sp3) architectures further illustrates the robustness and generality of Ni-OACs, thus offering a new gateway to expedite the design-make-test-analyze (DMTA) cycle in drug discover

The Risk of Endometrial Malignancy and Other Endometrial Pathology in Women with Abnormal Uterine Bleeding:An Ultrasound-Based Model Development Study by the IETA Group

Objectives: The aim of this study was to develop a model that can discriminate between different etiologies of abnormal uterine bleeding. Design: The International Endometrial Tumor Analysis 1 study is a multicenter observational diagnostic study in 18 bleeding clinics in 9 countries. Consecutive women with abnormal vaginal bleeding presenting for ultrasound examination (n = 2,417) were recruited. The histology was obtained from endometrial sampling, D&C, hysteroscopic resection, hysterectomy, or ultrasound follow-up for >1 year. Methods: A model was developed using multinomial regression based on age, body mass index, and ultrasound predictors to distinguish between: (1) endometrial atrophy, (2) endometrial polyp or intracavitary myoma, (3) endometrial malignancy or atypical hyperplasia, (4) proliferative/secretory changes, endometritis, or hyperplasia without atypia and validated using leave-center-out cross-validation and bootstrapping. The main outcomes are the model's ability to discriminate between the four outcomes and the calibration of risk estimates. Results: The median age in 2,417 women was 50 (interquartile range 43-57). 414 (17%) women had endometrial atrophy; 996 (41%) had a polyp or myoma; 155 (6%) had an endometrial malignancy or atypical hyperplasia; and 852 (35%) had proliferative/secretory changes, endometritis, or hyperplasia without atypia. The model distinguished well between malignant and benign histology (c-statistic 0.88 95% CI: 0.85-0.91) and between all benign histologies. The probabilities for each of the four outcomes were over- or underestimated depending on the centers. Limitations: Not all patients had a diagnosis based on histology. The model over- or underestimated the risk for certain outcomes in some centers, indicating local recalibration is advisable. Conclusions: The proposed model reliably distinguishes between four histological outcomes. This is the first model to discriminate between several outcomes and is the only model applicable when menopausal status is uncertain. The model could be useful for patient management and counseling, and aid in the interpretation of ultrasound findings. Future research is needed to externally validate and locally recalibrate the model

NLR locus-mediated trade-off between abiotic and biotic stress adaptation in Arabidopsis

Osmotic stress caused by drought, salt or cold decreases plant fitness. Acquired stress tolerance defines the ability of plants to withstand stress following an initial exposure. We found previously that acquired osmotolerance after salt stress is widespread among Arabidopsis thaliana accessions. Here, we identify ACQOS as the locus responsible for ACQUIRED OSMOTOLERANCE. Of its five haplotypes, only plants carrying group 1 ACQOS are impaired in acquired osmotolerance. ACQOS is identical to VICTR, encoding a nucleotide-binding leucine-rich repeat (NLR) protein. In the absence of osmotic stress, group 1 ACQOS contributes to bacterial resistance. In its presence, ACQOS causes detrimental autoimmunity, thereby reducing osmotolerance. Analysis of natural variation at the ACQOS locus suggests that functional and non-functional ACQOS alleles are being maintained due to a trade-off between biotic and abiotic stress adaptation. Thus, polymorphism in certain plant NLR genes might be influenced by competing environmental stresses

Risk assessment for endometrial cancer in women with abnormal vaginal bleeding : Results from the prospective IETA-1 cohort study

Objective: To investigate the association between personal history, anthropometric features and lifestyle characteristics and endometrial malignancy in women with abnormal vaginal bleeding. Methods: Prospective observational cohort assessed by descriptive and multivariable logistic regression analyses. Three features—age, body mass index (BMI; calculated as weight in kilograms divided by the square of height in meters), and nulliparity—were defined a priori for baseline risk assessment of endometrial malignancy. The following variables were tested for added value: intrauterine contraceptive device, bleeding pattern, age at menopause, coexisting diabetes/hypertension, physical exercise, fat distribution, bra size, waist circumference, smoking/drinking habits, family history, use of hormonal/anticoagulant therapy, and sonographic endometrial thickness. We calculated adjusted odds ratio, optimism-corrected area under the receiver operating characteristic curve (AUC), R2, and Akaike's information criterion. Results: Of 2417 women, 155 (6%) had endometrial malignancy or endometrial intraepithelial neoplasia. In women with endometrial cancer median age was 67 years (interquartile range [IQR] 56–75 years), median parity was 2 (IQR 0–10), and median BMI was 28 (IQR 25–32). Age, BMI, and parity produced an AUC of 0.82. Other variables marginally affected the AUC, adding endometrial thickness substantially increased the AUC in postmenopausal women. Conclusion: Age, parity, and BMI help in the assessment of endometrial cancer risk in women with abnormal uterine bleeding. Other patient information adds little, whereas sonographic endometrial thickness substantially improves assessment

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10.1111/gcb.14904GLOBAL CHANGE BIOLOGY261119-18