Self-incompatibility in Papaver Pollen:Programmed Cell Death in an Acidic Environment

Self-Incompatibility (SI) is a genetically controlled mechanism that prevents self-fertilisation and thus encourages outbreeding and genetic diversity. During pollination, most SI systems utilise cell-cell recognition to reject incompatible pollen. Mechanistically, one of the best-studied SI systems is that of Papaver rhoeas (poppy), which involves the interaction between the two S-determinants, a stigma-expressed secreted protein (PrsS) and a pollen-expressed plasma-membrane localised protein (PrpS). This interaction is the critical step in determining acceptance of compatible pollen or rejection of incompatible pollen. Cognate PrpS-PrsS interaction triggers a signalling network causing rapid growth arrest and eventually programmed cell death (PCD) in incompatible pollen. In this review, we provide an overview of recent advances in our understanding of the major components involved in the SI-induced PCD (SI-PCD). In particular, we focus on the importance of SI-induced intracellular acidification and consequences for protein function, and the regulation of soluble inorganic pyrophosphatase (Pr-p26.1) activity by post-translational modification. We also discuss attempts at the identification of protease(s) involved in the SI-PCD process. Finally, we outline future opportunities made possible by the functional transfer of the P. rhoeas SI system to Arabidopsis

Brain innate immunity in the regulation of neuroinflammation: therapeutic strategies by modulating cd200-cd200r interaction involve the cannabinoid system

The central nervous system (CNS) innate immune response includes an arsenal of molecules and receptors expressed by professional phagocytes, glial cells and neurons that is involved in host defence and clearance of toxic and dangerous cell debris. However, any uncontrolled innate immune responses within the CNS are widely recognized as playing a major role in the development of autoimmune disorders and neurodegeneration, with multiple sclerosis (MS) and Alzheimer´s disease (AD) being primary examples. Hence, it is important to identify the key regulatory mechanisms involved in the control of CNS innate immunity and which could be harnessed to explore novel therapeutic avenues. Neuroimmune regulatory proteins (NIReg) such as CD95L, CD200, CD47, sialic acid, complement regulatory proteins (CD55, CD46, fH, C3a), HMGB1, may control the adverse immune responses in health and diseases. In the absence of these regulators, when neurons die by apoptosis, become infected or damaged, microglia and infiltrating immune cells are free to cause injury as well as an adverse inflammatory response in acute and chronic settings. We will herein provide new emphasis on the role of the pair CD200-CD200R in MS and its experimental models: experimental autoimmune encephalomyelitis (EAE) and Theiler?s virus induced demyelinating disease (TMEV-IDD). The interest of the cannabinoid system as inhibitor of inflammation prompt us to introduce our findings about the role of endocannabinoids (eCBs) in promoting CD200-CD200 receptor (CD200R) interaction and the benefits caused in TMEV-IDD. Finally, we also review the current data on CD200-CD200R interaction in AD, as well as, in the aging brain.Fil: Hernangómez, Miriam. Consejo Superior de Investigaciones Cientificas; EspañaFil: Carrillo Salinas, Francisco. Consejo Superior de Investigaciones Cientificas; EspañaFil: Mecha, Miriam. Consejo Superior de Investigaciones Cientificas; EspañaFil: Correa, Fernando Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos; Argentina. Universidad de Buenos Aires. Facultad de Medicina; ArgentinaFil: Mestre, Leyre. Consejo Superior de Investigaciones Cientificas; EspañaFil: Loría, Frida. Consejo Superior de Investigaciones Cientificas; EspañaFil: Feliú, Ana. Consejo Superior de Investigaciones Cientificas; EspañaFil: Docagne, Fabian. Inserm; FranciaFil: Guaza, Carmen. Consejo Superior de Investigaciones Cientificas; Españ

Tackling Neuroinflammation After Traumatic Brain Injury:Complement Inhibition as a Therapy for Secondary Injury

Traumatic brain injury (TBI) is a leading cause of mortality, sensorimotor morbidity, and neurocognitive disability. Neuroinflammation is one of the key drivers causing secondary brain injury after TBI. Therefore, attenuation of the inflammatory response is a potential therapeutic goal. This review summarizes the most important neuroinflammatory pathophysiology resulting from TBI and the clinical trials performed to attenuate neuroinflammation. Studies show that non-selective attenuation of the inflammatory response, in the early phase after TBI, might be detrimental and that there is a gap in the literature regarding pharmacological trials targeting specific pathways. The complement system and its crosstalk with the coagulation system play an important role in the pathophysiology of secondary brain injury after TBI. Therefore, regaining control over the complement cascades by inhibiting overshooting activation might constitute useful therapy. Activation of the complement cascade is an early component of neuroinflammation, making it a potential target to mitigate neuroinflammation in TBI. Therefore, we have described pathophysiological aspects of complement inhibition and summarized animal studies targeting the complement system in TBI. We also present the first clinical trial aimed at inhibition of complement activation in the early days after brain injury to reduce the risk of morbidity and mortality following severe TBI.</p

Design of a fault tolerant airborne digital computer. Volume 2: Computational requirements and technology

This final report summarizes the work on the design of a fault tolerant digital computer for aircraft. Volume 2 is composed of two parts. Part 1 is concerned with the computational requirements associated with an advanced commercial aircraft. Part 2 reviews the technology that will be available for the implementation of the computer in the 1975-1985 period. With regard to the computation task 26 computations have been categorized according to computational load, memory requirements, criticality, permitted down-time, and the need to save data in order to effect a roll-back. The technology part stresses the impact of large scale integration (LSI) on the realization of logic and memory. Also considered was module interconnection possibilities so as to minimize fault propagation

Combining LC-MS/MS and genetic analysis to unravel plant hormone metabolism in Arabidopsis thaliana

Plants synthesize a myriad of metabolites, far more than those produced by most other organisms. Plant hormones are a unique set of compounds, with distinctive metabolism and properties that affect physiological processes during development and growth. Their underlying genetic variation will have attracted much research attention by virtue of junctions of NGS technologies and metabolomics. The aim of this thesis was to study natural variation of plant hormones in Arabidopsis. To obtain reliable quantitative data of levels of hormone using LC-ESI-MS, I first developed a set of methodological processes related to extraction and purification. A set of Arabidopsis ecotypes was chosen, and studied to earn various aspects of natural variation with traits of mature roots. Based on results of these works, my study has moved to classical linkage mapping analysis to find genetic loci responsible for levels of a few sets of hormone in roots and leaves of Arabidopsis. Chapter 2 describes the problem of matrix effects caused by impurities in semi-purified extracts, on the accuracy of data derived from LC-ESI-mass spectrometry. Matrix effects may result in both ion suppression and enhancement, and severely affects quantitative data of hormone levels. Without proper ways to minimize matrix effects, hormone data would be unreliable, and would not allow accurate QTL mapping. I validated a few key-points that are critical for determining the levels of a wide range of plant hormones in Arabidopsis extracts based on a one-step solid phase extraction (SPE) method. For the simplified purification of Arabidopsis extracts, a commercially available HLB sorbent was chosen to recover a wide range of chemically diverse series of hormone analytes. Dilution using a much smaller starting sample (e.g., 2.5 mg) reduced the matrix effects considerably but additional measures were required for most of the analytes. Flushing the HLB-SPE column with acidic methanol was more effective to reduce matrix effect than acetonitrile based eluent. At the end, I proposed a series of steps and procedures to optimize the protocol for hormone analysis in LC-ESI-MS. Chapter 3 describes natural variation of hormone levels found in 13 Arabidopsis ecotypes. Variations of hormone level among the accessions were remarkably small, viz., less than three-fold difference between extremes. For CKs, relatively larger variations were found for ribosides and glucosides, as compared to the free bases. Root phenotypic traits of these accessions were also measured, using a new parameter (mature root unit) for complex root systems, and correlation analyses were done between hormone data and mature root traits. For root phenotyping, length-related traits&mdash;lateral root length and total root length&mdash;showed larger variations than lateral root number-related ones. Antagonistic interactions between hormones (IAA and trans-zeatin) were detected for root weight. These findings provide enough basis to warrant a quantitative genetic analysis in plant hormone metabolism and crucial information for the choice of a proper segregating population. Chapter 4 reports diverse QTLs that are responsible for hormone levels of CKs, SA and JA in roots of Arabidopsis Ler&times;Cvi RIL population. QTL analysis of two sub-populations, viz., vegetative and flowering plants revealed that many of the QTLs were development-specific, suggesting that the transition to flowering has a profound effect on hormone metabolism. Using near-isogenic lines, several significant QTLs were confirmed; three co-localized QTL regions were responsible for determining several CK metabolites. Using a knock-out plant, a functional role of zeatin N-glucosyltransferase gene (UGT76C2) underlying a large-effect QTL for levels of tZ N-glucosides and tZRMP was evaluated in CK metabolism. Pleotropic effects of this gene were found for levels of CK in both roots and leaves, but significant changes of morphological traits were observed only in roots. This suggests that CK N- glucosides play an important role in root development. I also advocated the possibility of genetic regulation of concentration ratio between tZ7G and tZ9G based on a newly observed QTL of the trait. As a further step of QTL analysis after Chapter 4, the study was extended to leaves. Chapter 5 describes the analysis of 5 groups of hormones in rosette leaves of the same RIL population. QTL analysis showed a multitude of significant loci for levels of IAA, ABAs and CKs. Also for leaves, development-specific QTLs were detected in two sub-populations, vegetative and flowering lines. QTLs for ratios between hormone metabolites belonging to the same group but also to different groups were found and some of them partly co-localized with those of single compounds, implying that QTLs for single hormones may also affect the balance between hormones. The detection of QTLs for ratios between structurally unrelated hormones (e.g. auxin : ABA) and further fine mapping may help unravelling genetic elements underlying hormone interactions in the regulation of plant development and stress responses. Finally, in Chapter 6, several issues arising from the separate experiments are taken into consideration. The main significance of this PhD thesis is the experimental confirmation that finding QTLs for hormone metabolism is feasible and worth being extended to other populations of Arabidopsis and to crop plants. I anticipate that in the near future metabolomics study towards natural variation of plant hormones will be part of interesting theme in quantitative genetics. It will provide us to gain a better understanding of the complexity of molecular mechanism underlying hormone metabolism in plants

Immunomodulatory Hydrogels:Advanced Regenerative Tools for Diabetic Foot Ulcer

Diabetic foot ulcer (DFU) is one of the most common complications of diabetes, bringing physical and mental challenges for patients due to the lack of efficient curative therapy. Despite considerable advances in pharmacological and surgical approaches, clinical trials for DFU patients remain disappointing due to the local overactive and excessive inflammation. Immunomodulatory hydrogels has significant advantages to overcome the clinical challenge of DFUs therapy. Here, recent fabrication and regenerative advances in the utilization of functional hydrogels for altering the immune microenvironment of DFUs are comprehensively reviewed. The pathological features and the healing processes of DFUs, followed by summarizing the physicochemical properties essential for the design of regenerative hydrogels for immunomodulation in DFUs, are briefly introduced. Then, the potential immuno-therapeutic modalities of hydrogels and emerging trends used to treat DFUs via multitherapeutic approaches and enhanced efficacy and safety are discussed. Taken together, by linking the structural properties of hydrogels to their functions in DFU therapy with a particular focus on immunomodulatory stimuli, this review can promote further advances in designing advanced hydrogels for DFUs, resulting in improved diabetic wound repair through translation into clinical setting in the near future.</p

Cell Signaling in Model Plants

This book provides new and in-depth insights into molecular aspects of plant cell signaling in response to biotic, such as aphid- and grey mold disease-resistance, and abiotic stresses, such as soil salinity and drought stress, and additionally, functional analysis on signaling components involved in flowering, juvenility, GA signaling, and biosynthesis, and miRNA-regulated gene expression. Furthermore, plant acclimation was reported, with emphasis on mechanistic insights into the roles of brassinosteroids, cyclic AMP, and hydrogen sulfide, and the recent advances of transmembrane receptor-like kinases were refined. Clearly, plant cell signaling is an intensive topic and whether it is now or in the future, the emerging technology in functional analysis such as genome editing technologies, high-throughput technologies, integrative multiple-omics as well as bioinformatics can assist researchers to reveal novel aspects of the regulatory mechanisms of plant growth and development, and acclimation to environmental and biotic stresses. The achievement of such research will be useful in improving crop stress tolerances to increase agricultural productivity and sustainability for the food supply of the world

SPIRO- the automated Petri plate imaging platform designed by biologists, for biologists

Phenotyping of model organisms grown on Petri plates is often carried out manually, despite the procedures being time-consuming and laborious. The main reason for this is the limited availability of automated phenotyping facilities, whereas constructing a custom automated solution can be a daunting task for biologists. Here, we describe SPIRO, the Smart Plate Imaging Robot, an automated platform that acquires time-lapse photographs of up to four vertically oriented Petri plates in a single experiment, corresponding to 192 seedlings for a typical root growth assay and up to 2500 seeds for a germination assay. SPIRO is catered specifically to biologists' needs, requiring no engineering or programming expertise for assembly and operation. Its small footprint is optimized for standard incubators, the inbuilt green LED enables imaging under dark conditions, and remote control provides access to the data without interfering with sample growth. SPIRO's excellent image quality is suitable for automated image processing, which we demonstrate on the example of seed germination and root growth assays. Furthermore, the robot can be easily customized for specific uses, as all information about SPIRO is released under open-source licenses. Importantly, uninterrupted imaging allows considerably more precise assessment of seed germination parameters and root growth rates compared with manual assays. Moreover, SPIRO enables previously technically challenging assays such as phenotyping in the dark. We illustrate the benefits of SPIRO in proof-of-concept experiments which yielded a novel insight on the interplay between autophagy, nitrogen sensing, and photoblastic response