Biosynthesis and potential functions of the ecdysteroid 20-hydroxyecdysone — a review

Botany ◽  
2008 ◽  
Vol 86 (9) ◽  
pp. 978-987 ◽  
Author(s):  
Reginaldo A. Festucci-Buselli ◽  
Luis A. S. Contim ◽  
Luiz Cláudio A. Barbosa ◽  
Jeff Stuart ◽  
Wagner C. Otoni
Keyword(s):  
Active Compound ◽  
Steroid Hormone ◽  
Potential Functions ◽  
Current Understanding ◽  
Developmental Processes ◽  
Physiological Processes ◽  
Defensive Substance

The ecdysteroid 20-hydroxyecdysone (20E) is a steroid hormone found in arthropods and plants. It is suspected to have agrochemical, biotechnological, medicinal, and pharmaceutical applicability. In insects, 20E controls or elicits molting and other developmental processes, and several characterized P450 enzymes are involved in its biosynthesis. In plants, it may act as a defensive substance against insects and nematodes. It is suspected that 20E, being a physiologically active compound, may affect morphological and physiological processes in plants and that C27phytosterols may be its precursors. However, neither its precise function nor its mechanism of biosynthesis in plants is fully understood. Here, the importance of 20E and current understanding of its structure, potential functions, and biosynthesis in both plants and insects are reviewed.

scholarly journals Drugs modulating the L-arginine:NO:cGMP pathway – current use in therapy

2016 ◽  
Vol 29 (1) ◽  
pp. 14-20 ◽  
Author(s):  
Magdalena Polakowska ◽  
Jolanta Orzelska-Gorka ◽  
Sylwia Talarek
Keyword(s):  
Nitric Oxide ◽  
Central Nervous System ◽  
Nervous System ◽  
Cardiovascular Diseases ◽  
Significant Role ◽  
Current Understanding ◽  
Physiological Processes ◽  
Wide Range ◽  
The Central Nervous System ◽  
Pharmacological Profiles

AbstractNitric oxide (NO) is a relatively novel messenger that plays a significant role in a wide range of physiological processes. Currently, it is known that, both, lack and excess of NO can cause diseases, thus a lot of substances have been discovered and utilized which can change the concentration of this molecule within the organism. The aim of the present work is to provide an overview of currently used agents modulating the L-arginine:NO:cGMP pathway, as well as to summarize current understanding of their pharmacological profiles. Nowadays, most of these agents are employed particularly in the treatment of cardiovascular diseases. Further studies can hold promise for enhancing the therapeutic equipment for a variety of other impairments, such as osteoporosis, and also in treatments of the central nervous system.

Mechanisms of disease: the endocrinology of ectopic pregnancy

2012 ◽  
Vol 14 ◽  
Author(s):  
Andrew W. Horne ◽  
Hilary O.D. Critchley
Keyword(s):  
Ectopic Pregnancy ◽  
Fallopian Tube ◽  
Medical Management ◽  
Potential Functions ◽  
Current Understanding ◽  
Socioeconomic Impact ◽  
Review Of The Literature ◽  
Comprehensive Review ◽  
Novel Biomarkers ◽  
New Treatments

Ectopic pregnancy is defined as a pregnancy implanted outside the uterus, and >98% implant in the Fallopian tube. It has a major clinical and socioeconomic impact worldwide. The diagnosis of ectopic pregnancy is often difficult and resource intensive owing to a lack of accurate biomarkers, and there is a need for improved medical management of ectopic pregnancy using new or adjuvant treatments. The aetiology of ectopic pregnancy is uncertain, but tubal implantation is probably due to retention of the embryo in the Fallopian tube owing to impaired embryo-tubal transport and alterations in the tubal microenvironment. This comprehensive review of the literature supporting current understanding of the endocrinology of Fallopian tube biology and tubal implantation focuses on genes expressed in the Fallopian tube regulated by oestrogen and progesterone and discusses their potential functions. It concludes with a discussion of how advances in this field are enabling the development of novel biomarkers and could lead to the identification of potential new treatments for ectopic pregnancy.

scholarly journals Membrane progesterone receptor induces meiosis in Xenopus oocytes through endocytosis into signaling endosomes and interaction with APPL1 and Akt2

PLoS Biology ◽  
2020 ◽  
Vol 18 (11) ◽  
pp. e3000901
Author(s):  
Nancy Nader ◽  
Maya Dib ◽  
Rawad Hodeify ◽  
Raphael Courjaret ◽  
Asha Elmi ◽  
...  
Keyword(s):  
Nuclear Receptors ◽  
Xenopus Oocytes ◽  
Steroid Hormone ◽  
Adaptor Protein ◽  
G Protein Coupled Receptors ◽  
Adiponectin Receptors ◽  
Physiological Processes ◽  
Oocyte Meiosis ◽  
Membrane Progesterone Receptor ◽  
G Protein Coupled

The steroid hormone progesterone (P4) mediates many physiological processes through either nuclear receptors that modulate gene expression or membrane P4 receptors (mPRs) that mediate nongenomic signaling. mPR signaling remains poorly understood. Here we show that the topology of mPRβ is similar to adiponectin receptors and opposite to that of G-protein-coupled receptors (GPCRs). Using Xenopus oocyte meiosis as a well-established physiological readout of nongenomic P4 signaling, we demonstrate that mPRβ signaling requires the adaptor protein APPL1 and the kinase Akt2. We further show that P4 induces clathrin-dependent endocytosis of mPRβ into signaling endosome, where mPR interacts transiently with APPL1 and Akt2 to induce meiosis. Our findings outline the early steps involved in mPR signaling and expand the spectrum of mPR signaling through the multitude of pathways involving APPL1.

Seeing and Shaping Objects

2012 ◽  
Author(s):  
Peter S. Wells
Keyword(s):  
Cognitive Psychology ◽  
Optic Nerve ◽  
Current Understanding ◽  
Physiological Processes ◽  
Complex Process ◽  
Common Parlance ◽  
The Subject ◽  
The Brain

Current understanding of the basic optical and physiological processes involved in how we see is explained in a number of recent books on the subject by specialists in cognitive psychology and in the various branches of neuroscience. This chapter reviews some aspects of the topic that are particularly relevant to the subject of this book. Although in common parlance we speak of seeing with our eyes, in fact we do not see with our eyes, but with our brains. The eyes conduct light, via the retina at the back of the eyeball and the optic nerve, to the various different regions of the brain that are involved in seeing; as many as thirty have been suggested by neuroscientists. Seeing is thus a complex process that takes place in conjunction with other processes in which the brain is involved.

The Reproductive Biology of the Rabbit Flea Spilopsyllus Cuniculi (Dale) and The Dependence of this Species Upon the Breeding of Its Host

1964 ◽  
Vol 41 (2) ◽  
pp. 371-402
Author(s):  
A. R. MEAD-BRIGGS
Keyword(s):  
Critical Point ◽  
Reproductive Biology ◽  
Ovarian Development ◽  
Steroid Hormone ◽  
Corpus Allatum ◽  
Pregnant Female ◽  
Ovarian Activity ◽  
Developmental Processes ◽  
Hormone Levels ◽  
Adult Insect

1. Unlike any other species of flea which has been cultured successfully Spilopsyllus cumculi (Dale) is entirely dependent for its own reproduction upon its host becoming pregnant. 2. The ovaries of fleas kept on male or non-pregnant female rabbits remain immature whereas those on a pregnant host are mature at the time of parturition. Vitellogenesis commences at a critical point approximately 7 days pre-partum, irrespective of how long the fleas have been on the host. It is postulated that a factor required by the flea for ovarian development is only available during the final week of pregnancy, and not at all in male or non-pregnant rabbits. The factor disappears from the adult after parturition but is present in her nestlings for at least 7 days. 3. Most fleas desert the adult doe shortly after the young are born and enter her nest, where copulation and oviposition occur. 4. The factor does not act solely as a trigger initiating in the flea developmental processes which then continue in its absence; ovarian regression occurs among maturing fleas transferred to hosts that do not supply the factor. 5. The processes of vitellogenesis, not those of oogenesis, fail in the absence of the factor. It is suggested that the ‘yolk-forming hormone’ normally secreted by the corpus allatum of the adult insect may only be produced by rabbit fleas when they can obtain the postulated factor. Variations in the quantity of this factor available to fleas on different hosts could explain the observed variations in ovarian activity. Some parallels between the factor and steroid hormone levels in the host's blood are discussed.

scholarly journals The activity of peroxidases and superoxide dismutases in transgenic phosphinothricin-resistant lotus corniculatus shoots

2010 ◽  
Vol 62 (4) ◽  
pp. 1063-1070 ◽  
Author(s):  
Jelena Savic ◽  
Jelena Platisa ◽  
M. Dragicevic ◽  
Radomirka Nikolic ◽  
Nevena Mitic ◽  
...  
Keyword(s):  
Antioxidative Enzymes ◽  
Active Compound ◽  
Genetically Modified ◽  
Lotus Corniculatus ◽  
Superoxide Dismutases ◽  
Herbicide Application ◽  
Physiological Processes ◽  
Oxidative Balance ◽  
Selective Herbicide

The aim of this study was to investigate the effect of the non-selective herbicide Basta?, with phosphinothricin (PPT) as active compound, on antioxidative enzymes in transgenic PPT-resistant Lotus corniculatus cv. Bokor shoots grown under in vitro conditions. Analysis of peroxidases (POD) and superoxide dismutases (SOD) showed that the activity of these enzymes was affected by herbicide application more in control PPT-sensitive than in transformed resistant shoots. These results confirmed the capacity of genetically modified resistant shoots to reduce the influence of PPT on the physiological processes and disturbance of oxidative balance in cells.

scholarly journals Visualizing the action of steroid hormone receptors in living cells

2007 ◽  
Vol 5 (1) ◽  
pp. nrs.05003 ◽  
Author(s):  
Alexander Griekspoor ◽  
Wilbert Zwart ◽  
Jacques Neefjes ◽  
Rob Michalides
Keyword(s):  
Scientific Community ◽  
Hormone Receptors ◽  
Steroid Hormone ◽  
Living Cells ◽  
Steroid Hormone Receptors ◽  
Complex Nature ◽  
Physiological Processes ◽  
Biophysical Techniques ◽  
Native Context ◽  
External Stimuli

Transcription controlled by Steroid Hormone Receptors (SHRs) plays a key role in many important physiological processes like organ development, metabolite homeostasis, and response to external stimuli. Understandably, the members of this family have drawn a lot of attention from the scientific community since their discovery, four decades ago. Still, after many years of research we are only beginning to unravel the complex nature of these receptors. The pace at which we do has improved significantly in recent years with the discovery of genetically encoded fluorescent probes, and the accompanying revival of biophysical approaches that allow more detailed study of SHRs. Here, we will look into the different aspects of SHR signalling, and discuss how biophysical techniques have contributed to visualizing their function in their native context, the living cell.

scholarly journals Hypothalamic Actions of SIRT1 and SIRT6 on Energy Balance

2021 ◽  
Vol 22 (3) ◽  
pp. 1430
Author(s):  
Mar Quiñones ◽  
Eva Martínez-Grobas ◽  
Johan Fernø ◽  
Raquel Pérez-Lois ◽  
Luisa María Seoane ◽  
...  
Keyword(s):  
Energy Balance ◽  
Current Understanding ◽  
Metabolic Responses ◽  
Metabolic Complications ◽  
Physiological Processes

Sirtuins are NAD+ dependent deacetylases that regulate a large number of physiological processes. These enzymes are highly conserved and act as energy sensors to coordinate different metabolic responses in a controlled manner. At present, seven mammalian sirtuins (SIRT 1-7) have been identified, with SIRT1 and SIRT6 shown to exert their metabolic actions in the hypothalamus, both with crucial roles in eliciting responses to dampen metabolic complications associated with obesity. Therefore, our aim is to compile the current understanding on the role of SIRT1 and SIRT6 in the hypothalamus, especially highlighting their actions on the control of energy balance.

scholarly journals Unanswered Questions Regarding Sex and BMP/TGF-β Signaling

2018 ◽  
Author(s):  
Tapan A. Shah ◽  
Melissa B. Rogers
Keyword(s):  
Signaling Pathways ◽  
Adult Life ◽  
Bmp Signaling ◽  
Current Understanding ◽  
Tgf Beta ◽  
Developmental Processes ◽  
Men And Women ◽  
Cardiovascular Pathologies

Crosstalk between the BMP and TGF-β signaling pathways regulates many complex developmental processes from the earliest stages of embryogenesis throughout adult life. In many situations, the two signaling pathways act reciprocally. For example, TGF-β signaling is generally pro-fibrotic whereas BMP signaling is anti-fibrotic and pro-calcific. Sex-specific differences occur in many diseases including cardiovascular pathologies. Differing ratios of fibrosis and calcification in stenotic valves suggests that BMP/TGF-β signaling may vary in men and women. In this review, we focus on the current understanding of the interplay between sex and BMP/TGF-β signaling and pose several unanswered questions.

Wnt gradient formation: from source to sink

2006 ◽  
Vol 56 (4) ◽  
pp. 425-446 ◽  
Author(s):  
Hendrik Korswagen ◽  
Damien Coudreuse
Keyword(s):  
Concentration Gradient ◽  
Signalling Pathway ◽  
Current Understanding ◽  
Morphogenetic Field ◽  
Developmental Processes ◽  
Source To Sink ◽  
Gradient Formation ◽  
Wnt Ligands

AbstractThe secreted glycoproteins of the Wnt family activate a highly conserved signalling pathway that controls several developmental processes. Wnt ligands function as morphogens that act at a distance from their source by establishing a concentration gradient. The various fates of the Wnt responding cells along the morphogenetic field contribute to the precise patterning of the embryo and depend on the concentration of morphogen to which they are exposed. However, the different mechanisms that allow the controlled formation of the Wnt gradient are unclear. Here we give an overview of current understanding of the mechanisms that potentially control the spreading of the Drosophila Wnt ortholog Wingless.

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