Oscillation and nonoscillation of third order functional differential equations

A qualitative approach is usually concerned with the behavior of solutions of a given differential equation and usually does not seek specific explicit solutions;This dissertation is the analysis of oscillation of third order linear homogeneous functional differential equations, and oscillation and nonoscillation of third order nonlinear nonhomogeneous functional differential equations. This is done mainly in Chapters II and III. Chapter IV deals with the analysis of solutions of neutral differential equations of third order and even order. In Chapter V we study the asymptotic nature of nth order delay differential equations;Oscillatory solution is the solution which has infinitely many zeros; otherwise, it is called nonoscillatory solution;The functional differential equations under consideration are:(UNFORMATTED TABLE OR EQUATION FOLLOWS) (b(ay[superscript]\u27)[superscript]\u27)[superscript]\u27 + (q[subscript]1y)[superscript]\u27 + q[subscript]2y[superscript]\u27 = 0, &(b(ay[superscript]\u27)[superscript]\u27)[superscript]\u27 + q[subscript]1y + q[subscript]2y(t - [tau]) = 0, &(b(ay[superscript]\u27)[superscript]\u27)[superscript]\u27 + qF(y(g(t))) = f(t), &(y(t) + p(t)y(t - [tau]))[superscript]\u27\u27\u27 + f(t, y(t), y(t - [sigma])) = 0, &(y(t) + p(t)y(t - [tau]))[superscript](n) + f(t, y(t), y(t - [sigma])) = 0, and &y[superscript](n) + p(t)f(t, y[tau], y[subscript]sp[sigma][subscript]1\u27,..., y[subscript]sp[sigma][subscript]n[subscript]1(n-1)) = F(t). (TABLE/EQUATION ENDS);The first and the second equations are considered in Chapter II, where we find sufficient conditions for oscillation. We study the third equation in Chapter III and conditions have been found to ensure the required criteria. In Chapter IV, we study the oscillation behavior of the fourth and the fifth equations. Finally, the last equation has been studied in Chapter V from the point of view of asymptotic nature of its nonoscillatory solutions

5-azacytidine promotes microspore embryogenesis initiation by decreasing global DNA methylation,but prevents subsequent embryo development in rapeseed and barley

17 p.-10 fig.Microspores are reprogrammed by stress in vitro toward embryogenesis. This process is an important tool in breeding to obtain double-haploid plants. DNA methylation is a major epigenetic modification that changes in differentiation and proliferation. We have shown changes in global DNA methylation during microspore reprogramming. 5-Azacytidine (AzaC) cannot be methylated and leads to DNA hypomethylation. AzaC is a useful demethylating agent to study DNA dynamics, with a potential application in microspore embryogenesis. This work analyzes the effects of short and long AzaC treatments on microspore embryogenesis initiation and progression in two species, the dicot Brassica napus and the monocot Hordeum vulgare. This involved the quantitative analyses of proembryo and embryo production, the quantification of DNA methylation, 5-methyl-deoxy-cytidine (5mdC) immunofluorescence and confocal microscopy, and the analysis of chromatin organization (condensation/decondensation) by light and electron microscopy. Four days of AzaC treatments (2.5 μM) increased embryo induction, response associated with a decrease of DNA methylation, modified 5mdC, and heterochromatin patterns compared to untreated embryos. By contrast, longer AzaC treatments diminished embryo production. Similar effects were found in both species, indicating that DNA demethylation promotes microspore reprogramming, totipotency acquisition, and embryogenesis initiation, while embryo differentiation requires de novo DNA methylation and is prevented by AzaC. This suggests a role for DNA methylation in the repression of microspore reprogramming and possibly totipotency acquisition. Results provide new insights into the role of epigenetic modifications in microspore embryogenesis and suggest a potential benefit of inhibitors, such as AzaC, to improve the process efficiency in biotechnology and breeding programs.Work supported by projects (references BFU2008-00203, BFU2011-23752, AGL2014-52028-R) funded by the Spanish Ministry of Economy and Competitiveness (MINECO) and the European Regional Development Fund (ERDF/FEDER). AAET is recipient of a predoctoral fellowship of the JAE-Pre Program of the Spanish National Research Council, CSIC (JAEPre2010-052), cofunded by ERDF/FEDER.Peer reviewe

Evaluation of growth and nutritional value of Brassica microgreens grown under red, blue and green LEDs combinations

39 p.-7 fig.-2 tab.-9 tab. supl.Microgreens are rich functional crops with valuable nutritional elements that have health benefits when used as food supplements. Growth characterization,nutritional composition profile of 21 varieties representing five species of the Brassica genus asmicrogreens were assessed under light-emitting diodes(LEDs) conditions. Microgreens were grown under four different LEDs ratios(%); red:blue 80:20 and 20:80 (R80:B20 and R20:B80), or red:green:blue 70:10:20 and 20:10:70 (R70:G10:B20 and R20:G10:B70). Results indicated that supplemental lighting with green LEDs (R70:G10:B20) enhanced vegetative growth and morphology, while blue LEDs (R20:B80) increased the mineral and vitamin contents. Interestingly, by linking the nutritional content with the growth yield to define the optimal LEDs setup, we found that the best lighting to promote the microgreen growth was the green LEDs combination (R70:G10:B20). Remarkably, under the green LEDs combination (R70:G10:B20) conditions,the microgreens of Kohlrabi purple, Cabbage red, Broccoli, Kale Tucsan, Komatsuna red, Tatsoi and Cabbage green, which can benefit human health in conditions with limited food, had the highest growth and nutritional content.This research work is a part of a project received seed funding from the Dubai Future Foundation through the Guaana.com open research platform(grant no. MBR026). Dr. Mortaza is supported from ERDF project “Plants as a tool from sustainable global development” No. CZ.02.1.01/0.0/0.0/16_019/0000827.Peer reviewe

Changes in DNA methylation levels and nuclear distribution patterns after microspore reprogramming to embryogenesis in barley

26 p.-5 fig.The microspore can be induced in vitro, under specific stress treatments, to deviate from its gametophytic development and to reprogram towards embryogenesis, becoming a totipotent cell and forming haploid embryos which can further regenerate homozygous plants for production of new isogenic lines, an important biotechnological tool for crop breeding. DNA methylation constitutes a prominent epigenetic modification of the chromatin fibre which regulates gene expression. Changes in DNA methylation accompany the reorganization of the nuclear architecture during plant cell differentiation and proliferation, however, global DNA methylation and genome-wide expression patterns relationship is still poorly understood.In this work, the dynamics of global DNA methylation levels and distribution patterns have been analyzed during microspore reprogramming to embryogenesis and during pollen development in Hordeum vulgare. Quantification of global DNA methylation levels and 5-methyl-deoxy-cytidine (5mdC) immunofluorescence has been conducted at specific stages of pollen development and after reprogramming to embryogenesis, to analyze the epigenetic changes that accompany the change of developmental programme and cell fate. Results showed low DNA methylation levels in microspores and a high increase along pollen development and maturation; an intense 5mdC signal was concentrated in the generative and sperm nuclei whereas the vegetative nucleus exhibited lower DNA methylation signal. After the inductive stress treatment, low methylation levels and faint 5mdC signal were observed on nuclei of reprogrammed microspores and 2-4 cell proembryos. This data revealed a global DNA hypomethylation during the change of the developmental programme and first embryogenic divisions, in contrast with the hypermethylation of generative and sperm cells of the male germline accomplished during pollen maturation, suggesting an epigenetic regulation after microspore embryogenesis induction. At later embryogenesis stages global DNA methylation progressively increased, accompanying embryo development and differentiation events, like in zygotic embryos, supporting that DNA methylation is critical for the regulation of microspore embryogenesis gene expression.Work supported by Spanish Ministry of Economy and Competitivity (MINECO) project BFU2011-23752 and Spanish National Research Council (CSIC) project PIE 201020E038. AA-ET is recipient of a JAE predoctoral fellowship of CSIC (JAEPre2010-052).Peer reviewe

El tratamiento con 5-azacitidina hipometila el DNA y favorece la reprogramación e inicio de embriogénesis en cultivos de microsporas de colza y cebada

Trabajo presentado en la XI Reunión de la Sociedad Española de Cultivo in Vitro de Tejidos Vegetales, celebrada en Valencia (España) del 03 al 04 de septiembre de 2015.Peer reviewe

5-azacytidine improves microspore embryogenesis initiation by decreasing global DNA methylation while it impairs embryo progression in rapeseed and barley

Resumen del trabajo presentad en la XXI Reunión de la Sociedad Española de Fisiología Vegetal y al XIV Congreso Hispano-luso de Fisiología Vegetal, celebradas en Toledo (España) del 14 al 17 de junio de 2015.Microspores are reprogrammed by stress treatments in vitro, changing their developmental pathway to embryogenesis; the process, microspore embryogenesis, represents an important tool in plant breeding to obtain double-haploid plants. DNA methylation is a major epigenetic modification which changes during plant cell differentiation and proliferation, regulating gene expression. Recently, we have shown modifications in global DNA methylation that accompany the microspore reprogramming to embryogenesis. 5-Azacytidine (AzaC), known analog of 5-cytosine, cannot be methylated and leads to DNA hypomethylation in eukaryotic cells, constituting a useful demethylating agent to study DNA epigenetic dynamics, with potential application to improve the efficiency of microspore embryogenesis. This work analyzes for the first time effects of short and long AzaC treatments on microspore embryogenesis induction and progression in two species, the dicot Brassica napus (rapeseed) and the monocot Hordeum vulgare (barley). Quantitative analyses of pro-embryos formed after induction and embryo production, quantification of global DNA methylation levels, 5mdC immunofluorescence at confocal microscope were performed in 2.5 µM AzaC-treated and untreated cultures. Short AzaC treatments produced significant increases of embryogenesis induction rates, by decreasing global DNA methylation levels and modifying 5mdC distribution patterns. In contrast, longer AzaC treatments dramatically diminished embryo production. Similar effects were found in both species indicating that DNA demethylation favors microspore reprogramming, totipotency acquisition and embryogenesis initiation, while subsequent embryo differentiation requires de novo DNA methylation and is impaired by AzaC. Results give new insights into the role of epigenetic mark dynamics by epigenetic inhibitors, like AzaC, in stress-induced microspore embryogenesis, improving its efficiency in biotechnology and agronomic breeding programs.Work supported by projects (BFU2011-23752 and AGL2014-52028-R) funded by the Spanish Ministry of Economy and Competitiveness (MINECO) and the European Regional Development Fund (ERDF/FEDER) of the European Commission

Stress-Induced Microspore Embryogenesis Requires Endogenous Auxin Synthesis and Polar Transport in Barley

© 2019 Pérez-Pérez, El-Tantawy, Solís, Risueño and Testillano.Stress-induced microspore embryogenesis is a model in vitro system of cell reprogramming, totipotency acquisition, and embryo development. After induction, responsive microspores abandon their developmental program to follow an embryogenic pathway, leading to in vitro embryo formation. This process is widely used to produce doubled-haploid lines, essential players to create new materials in modern breeding programs, particularly in cereals, although its efficiency is still low in many crop species, because the regulating mechanisms are still elusive. Stress signaling and endogenous hormones, mainly auxin, have been proposed as determinant factors of microspore embryogenesis induction in some eudicot species; however, much less information is available in monocot plants. In this study, we have analyzed the dynamics and possible role of endogenous auxin during stress-induced microspore embryogenesis in the monocot Hordeum vulgare, barley. The results showed auxin accumulation in early proembryo cells, from embryogenesis initiation and a further increase with embryo development and differentiation, correlating with the induction and expression pattern of the auxin biosynthesis gene HvTAR2-like. Pharmacological treatments with kynurenine, inhibitor of auxin biosynthesis, and α-(p-chlorophenoxy)-isobutyric acid (PCIB), auxin antagonist, impaired embryogenesis initiation and development, indicating that de novo auxin synthesis and its activity were required for the process. Efflux carrier gene HvPIN1-like was also induced with embryogenesis initiation and progression; auxin transport inhibition by N-1-naphthylphthalamic acid significantly reduced embryo development at early and advanced stages. The results indicate activation of auxin biosynthesis with microspore embryogenesis initiation and progression, in parallel with the activation of polar auxin transport, and reveal a central role of auxin in the process in a monocot species. The findings give new insights into the complex regulation of stress-induced microspore embryogenesis, particularly in monocot plants for which information is still scarce, and suggest that manipulation of endogenous auxin content could be a target to improve in vitro embryo production.Work supported by projects AGL2014-52028-R and AGL2017-82447-R funded by the National Agency of Research (AEI), Spanish Ministry of Economy and Competitiveness (MINECO) and the European Regional Development Fund (ERDF/FEDER). YPP was recipient of a grant (PEJ15/BIO/AI-01S8) funded by Comunidad de Madrid and European Regional Development Funds (ERDF/FEDER). AAET was recipient of a grant (JAEPre2010-052) from the JAEPre Program funded by CSIC and European Regional Development Funds (ERDF/FEDER). We acknowledge support of the publication fee by the CSIC Open Access Publication Support Initiative through its Unit of Information Resources for Research (URICI)

Arabinogalactan protein profiles and distribution patterns during microspore embryogenesis and pollen development in Brassica napus

13 páginas, 8 figuras -- PAGS nros. 231-243Arabinogalactan proteins (AGPs), present in cell walls, plasma membranes and extracellular secretions, are massively glycosylated hydroxyproline-rich proteins that play a key role in several plant developmental processes. After stress treatment, microspores cultured in vitro can reprogramme and change their gametophytic developmental pathways towards embryogenesis, thereby producing embryos which can further give rise to haploid and double haploid plants, important biotechnological tools in plant breeding. Microspore embryogenesis constitutes a convenient system for studying the mechanisms underlying cell reprogramming and embryo formation. In this work, the dynamics of both AGP presence and distribution were studied during pollen development and microspore embryogenesis in Brassica napus, by employing a multidisciplinary approach using monoclonal antibodies for AGPs (LM2, LM6, JIM13, JIM14, MAC207) and analysing the expression pattern of the BnAGP Sta 39–4 gene. Results showed the developmental regulation and defined localization of the studied AGP epitopes during the two microspore developmental pathways, revealing different distribution patterns for AGPs with different antigenic reactivity. AGPs recognized by JIM13, JIM14 and MAC207 antibodies were related to pollen maturation, whereas AGPs labelled by LM2 and LM6 were associated with embryo development. Interestingly, the AGPs labelled by JIM13 and JIM14 were induced with the change of microspore fate. Increases in the expression of the Sta 39–4 gene, JIM13 and JIM14 epitopes found specifically in 2–4 cell stage embryo cell walls, suggested that AGPs are early molecular markers of microspore embryogenesis. Later, LM2 and LM6 antigens increased progressively with embryo development and localized on cell walls and cytoplasmic spots, suggesting an active production and secretion of AGPs during in vitro embryo formation. These results give new insights into the involvement of AGPs as potential regulating/signalling molecules in microspore reprogramming and embryogenesisThanks are due to the European COST Action FA0903 on Harnessing Plant Reproduction for Crop Improvement (HAPRECI). This work has been supported by the Spanish Ministry of Economy and Competitivity (MINECO) project BFU2011-23752, the Spanish National Research Council (CSIC) project PIE 201020E038 and the Spanish-Portuguese Joint Project “Accion Integrada” PRI-AIBPT-2011-0763. AA-ET is a recipient of a JAE predoctoral fellowship of the CSIC (JAEPre2010-052)Peer reviewe

Tailor-Made Specific Recognition of Cyromazine Pesticide Integrated in a Potentiometric Strip Cell for Environmental and Food Analysis

Screen-printed ion-selective electrodes were designed and characterized for the assessment of cyromazine (CYR) pesticide. A novel approach is to design tailor-made specific recognition sites in polymeric membranes using molecularly imprinted polymers for cyromazine (CR) determination (sensor I). Another sensor (sensor II) is the plasticized PVC membrane incorporating cyromazine/tetraphenyl borate ion association complex. The charge-transfer resistance and water layer reached its minimal by incorporating Polyaniline (PANI) solid-contact ISE. The designed electrodes demonstrated Nernstain response over a linear range 1.0 × 10−2–5.2 × 10−6 and 1.0 × 10−2–5.7 × 10−5 M with a detection limit 2.2 × 10−6 and 8.1 × 10−6 M for sensors I and II, respectively. The obtained slopes were 28.1 ± 2.1 (r2 = 0.9999) and 36.4 ± 1.6 (r2 = 0.9991) mV/decade, respectively. The results showed that the proposed electrodes have a fast and stable response, good reproducibility, and applicability for direct measurement of CYR content in commercial pesticide preparations and soil samples sprayed with CYR pesticide. The results obtained from the proposed method are fairly in accordance with those using the standard official method