The four lysine-specific histone demethylases of Arabidopsis differentially contribute to the control of flowering time and defence responses.

""Individual histone modifications, or a specific combination of them, act as signals ('histone code') that are 'read' by other proteins able to influence chromatin structure and gene expression. Among them, histone methylation is an important epigenetic modification controlled by a balance between methylation and demethylation. In Arabidopsis, four lysine-specific histone demethylases (AtLSDs) are present. To determine their physiological roles, loss-of-function mutants and 35S::AtLSD transgenic plants were obtained and analysed under physiological and stress conditions. Furthermore, to determine the AtLSD specific targets, the expression levels of flowering regulators, as well of senescence and stress marker genes were assessed in the transgenic plants. The expression pattern of the four AtLSDs was also analysed in detail by histochemical staining of beta-glucuronidase (GUS) in AtLSD::GUS transgenic plants. Data indicate involvement of the various AtLSDs in the control of flowering time, as well as in defence responses to salt stress. Overall, this study highlights functional similarities, but also important differences among the four members of the AtLSD gene family.INGLESE"

A plant spermine oxidase/dehydrogenase regulated by the proteasome and polyamines.

Polyamine oxidases (PAOs) are flavin-dependent enzymes involved in polyamine catabolism. In Arabidopsis five PAO genes (AtPAO1-AtPAO5) have been identified which present some common characteristics, but also important differences in primary structure, substrate specificity, subcellular localization, and tissue-specific expression pattern, differences which may suggest distinct physiological roles. In the present work, AtPAO5, the only so far uncharacterized AtPAO which is specifically expressed in the vascular system, was partially purified from 35S::AtPAO5-6His Arabidopsis transgenic plants and biochemically characterized. Data presented here allow AtPAO5 to be classified as a spermine dehydrogenase. It is also shown that AtPAO5 oxidizes the polyamines spermine, thermospermine, and N (1)-acetylspermine, the latter being the best in vitro substrate of the recombinant enzyme. AtPAO5 also oxidizes these polyamines in vivo, as was evidenced by analysis of polyamine levels in the 35S::AtPAO5-6His Arabidopsis transgenic plants, as well as in a loss-of-function atpao5 mutant. Furthermore, subcellular localization studies indicate that AtPAO5 is a cytosolic protein undergoing proteasomal control. Positive regulation of AtPAO5 expression by polyamines at the transcriptional and post-transcriptional level is also shown. These data provide new insights into the catalytic properties of the PAO gene family and the complex regulatory network controlling polyamine metabolism

A plant spermine oxidase/dehydrogenase regulated by the proteasome and polyamines

AtPAO5 is a spermine dehydrogenase oxidizing spermine, thermospermine, and N-1-acetylspermine through a polyamine back-conversion pathway. AtPAO5 has a cytosolic localization and is regulated transcriptionally and/or post-transcriptionally by the proteasome and polyamines.Polyamine oxidases (PAOs) are flavin-dependent enzymes involved in polyamine catabolism. In Arabidopsis five PAO genes (AtPAO1AtPAO5) have been identified which present some common characteristics, but also important differences in primary structure, substrate specificity, subcellular localization, and tissue-specific expression pattern, differences which may suggest distinct physiological roles. In the present work, AtPAO5, the only so far uncharacterized AtPAO which is specifically expressed in the vascular system, was partially purified from 35S::AtPAO5-6His Arabidopsis transgenic plants and biochemically characterized. Data presented here allow AtPAO5 to be classified as a spermine dehydrogenase. It is also shown that AtPAO5 oxidizes the polyamines spermine, thermospermine, and N-1-acetylspermine, the latter being the best in vitro substrate of the recombinant enzyme. AtPAO5 also oxidizes these polyamines in vivo, as was evidenced by analysis of polyamine levels in the 35S::AtPAO5-6His Arabidopsis transgenic plants, as well as in a loss-of-function atpao5 mutant. Furthermore, subcellular localization studies indicate that AtPAO5 is a cytosolic protein undergoing proteasomal control. Positive regulation of AtPAO5 expression by polyamines at the transcriptional and post-transcriptional level is also shown. These data provide new insights into the catalytic properties of the PAO gene family and the complex regulatory network controlling polyamine metabolism

The Prognostic Utility of Lymphocyte-Based Measures and Ratios in Chemotherapy-Induced Febrile Neutropenia Patients following Granulocyte Colony-Stimulating Factor Therapy

Background and Objectives: Chemotherapy-induced febrile neutropenia is the most widespread oncologic emergency with high morbidity and mortality rates. Herein we present a retrospective risk factor identification study to evaluate the prognostic role of lymphocyte-based measures and ratios in a cohort of chemotherapy-induced febrile neutropenia patients following granulocyte colony-stimulating factor (G-CSF) therapy. Materials and Methods: The electronic medical records at our center were utilized to identify patients with a first attack of chemotherapy-induced febrile neutropenia and were treated accordingly with G-CSF between January 2010 to December 2020. Patients’ demographics and disease characteristics along with laboratory tests data were extracted. Prognosis-related indicators were the absolute neutrophil count (ANC) at admission and the following 6 days besides the length of stay and mortality rate. Results: A total of 80 patients were enrolled, which were divided according to the absolute lymphocyte count at admission into two groups, the first includes lymphopenia patients (n = 55) and the other is the non-lymphopenia group (n = 25) with a cutoff point of 700 lymphocytes/μL. Demographics and baseline characteristics were generally insignificant among the two groups but the white blood cell count was higher in the non-lymphopenia group. ANC, neutrophils percentage and ANC difference in reference to admission among the two study groups were totally insignificant. The same insignificant pattern was observed in the length of stay and the mortality rate. Univariate analysis utilizing the ANC difference compared to the admission day as the dependent variable, revealed no predictability role in the first three days of follow up for any of the variables included. However, during the fourth day of follow up, both WBC (OR = 0.261; 95% CI: 0.075, 0.908; p = 0.035) and lymphocyte percentage (OR = 1.074; 95% CI: 1.012, 1.141; p = 0.019) were marginally significant, in which increasing WBC was associated with a reduction in the likelihood of ANC count increase, compared to the lymphocyte percentage which exhibited an increase in the likelihood. In comparison, sequential ANC difference models demonstrated lymphocyte percentage (OR = 0.961; 95% CI: 0.932, 0.991; p = 0.011) and monocyte-to-lymphocyte ratio (OR = 7.436; 95% CI: 1.024, 54.020; p = 0.047) reduction and increment in the enhancement of ANC levels, respectively. The fifth day had WBC (OR = 0.790; 95% CI: 0.675, 0.925; p = 0.003) to be significantly decreasing the likelihood of ANC increment. Conclusions: we were unable to determine any concrete prognostic role of lymphocyte-related measures and ratios. It is plausible that several limitations could have influenced the results obtained, but as far as our analysis is concerned ALC role as a predictive factor for ANC changes remains questionable

A plant spermine oxidase/dehydrogenase regulated by the proteasome and polyamines

Polyamine oxidases (PAOs) are flavin-dependent enzymes involved in polyamine catabolism. In Arabidopsis five PAO genes (AtPAO1-AtPAO5) have been identified which present some common characteristics, but also important differences in primary structure, substrate specificity, subcellular localization, and tissue-specific expression pattern, differences which may suggest distinct physiological roles. In the present work, AtPAO5, the only so far uncharacterized AtPAO which is specifically expressed in the vascular system, was partially purified from 35S::AtPAO5-6His Arabidopsis transgenic plants and biochemically characterized. Data presented here allow AtPAO5 to be classified as a spermine dehydrogenase. It is also shown that AtPAO5 oxidizes the polyamines spermine, thermospermine, and N1-acetylspermine, the latter being the best in vitro substrate of the recombinant enzyme. AtPAO5 also oxidizes these polyamines in vivo, as was evidenced by analysis of polyamine levels in the 35S::AtPAO5-6His Arabidopsis transgenic plants, as well as in a loss-of-function atpao5 mutant. Furthermore, subcellular localization studies indicate that AtPAO5 is a cytosolic protein undergoing proteasomal control. Positive regulation of AtPAO5 expression by polyamines at the transcriptional and post-transcriptional level is also shown. These data provide new insights into the catalytic properties of the PAO gene family and the complex regulatory network controlling polyamine metabolism. \ua9 The Author 2014