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    • br Acknowledgements This work was supported by

    2022-12-12


    Acknowledgements This work was supported by grants from the Program for Changjiang Scholars and Innovative Research Team in University (IRT_14R28), the National Basic Research Program of China (973) (Grant No.: 2013CB733602), the Major Research Plan of the National Natural Science Foundation of China (21390204), the National Natural Science Foundation of China (Grant No.: 21636003, 21506090), Technology Support Program of Jiangsu (No. BE2014715), Natural Science Foundation of Jiangsu Grants (No. BK20141500), Open Fund by Jiangsu Key Lab of Biomass-based Green Fuels and Chemicals(No. JSBGFC14005), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), and the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD).
    Introduction One of the most primitive needs of all organisms is for their UM171 receptor to the daily and seasonal changes in light intensities. This question has been studied in many organisms as different forms of circadian rhythms. In the cyanobacterium Synechococcus PCC 7942 cell division, among other physiological processes, is under circadian regulation [1]. Similarly in the protozoon Euglina gracilis cell division is tightly regulated by circadian changes so that the organism is able to orchestrate growth on a daily basis. cAMP was identified to be the mediator for this process, the concentration of which oscillated with a periodicity of about 12 h, but by a process which was not influenced by changing light conditions [2]. In Synechococcus elongate, use of non-optimal codons allowed the organism to survive better at low temperature than if they were to be encoded by optimal codons [3]. To photosynthetic organisms light is not only a cue to the changing diurnal and seasonal cycle but also the very source from which energy is captured and consolidated at times of availability. Besides assimilating energy directly from light, organisms also require to regulate other physiological processes for optimal metabolic integration. Although light sensing phytochromes have been studied as key regulators of response to daily and seasonal changes, their presence in other organisms such as bacteria and fungi [4], [5] suggest their primacy as a light response regulator. cAMP was the first signaling molecule to be identified [6] and regulates diverse metabolic functions such as glycogen metabolism, ion channel activation, cardiac output [7]. Although its regulatory role in photosynthetic organisms, particularly in higher plants was debated [8] more recent experiments indicate its ubiquitous role as a signaling molecule [9]. cAMP concentration is subjected to stringent regulation by synthesis and breakdown [10]. We wanted to inquire the status of this secondary signaling molecule which could be an important aspect of adaptation to light by algae. Although eubacteria have only one adenylate cyclase [11], [12] most other organisms have multiple genes for adenylate cyclase. Cyanobacteria have genes coding for both the archetypal membrane bound as well as cytoplasmic forms of adenylate cyclases [13], [14]. In the genome of Arthrospira 22 genes have been identified as possible adenylate cyclases [15]. In this paper we report the light associated expression of CyaC, one of the major contributors to cAMP levels in the cyanobacterium A. platensis.
    Materials and methods
    Results and discussion
    Acknowledgements
    Introduction Neuropeptides represent the most common signaling molecules in the central nervous system and in the periphery involved in a wide range of physiological functions, acting as neurotransmitters, neuromodulators or hormones. Co-released with classical neurotransmitters, they can modulate many different processes. Several neuropeptides promote cellular plasticity during pathophysiological processes, tissue injury or stress situations. Among them, pituitary adenylate cyclase activating polypeptide (PACAP) is a highly effective cytoprotective neuropeptide that provides an endogenous control against a variety of tissue damaging stimuli. PACAP occurs in two amino acid forms: PACAP38 and 27, with PACAP38 being dominant in vertebrates (Vaudry et al., 2009). PACAP is found in highest concentrations in the nervous system, but it is present in endocrine glands and in other peripheral tissues. The presence of two main groups of receptors (specific PAC1; and VPAC1, VPAC2, which bind VIP with similar affinity), and the currently known eight splice variants of the PAC1 receptor may explain the diverse effects of PACAP in many organs and tissues (Dickson and Finlayson, 2009; Manecka et al., 2016; Moody et al., 2016; Reglodi and Tamas, 2016). PACAP acts via adenylate cyclase/protein kinase A (PKA)/mitogen activated protein kinase (MAPK) and phospholipase C/inositol triphosphate downstream signaling pathways, but also acts on calcium release and transactivates tyrosine kinase receptors (Dickson and Finlayson, 2009; Manecka et al., 2016; Moody et al., 2016). The action on the signaling pathways and thus, the physiological or pharmacological effects depend on the expressed receptors, tissue/cell types and other factors present in the environment (Vaudry et al., 2009).