Hormonal actions in the Protozoan stress: A review

Acta Microbiologica et Immunologica Hungarica

2016

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The unicellular ciliate Tetrahymena is a complete organism, one of the most highly developed protozoans, which has specialized organelles performing each of the functions characteristic to the cells of higher ranked animals. It is also able to produce, store, and secrete hormones of higher ranked animals and also react to them. It produces lectins that can bind them and has functions, which are influenced by exogenous lectins. The review lists the observations on the relationship between lectins and Tetrahymena and try to construe them on the basis of the data, which are at our disposal. Considering the data, lectins can be used by Tetrahymena as materials for influencing conjugation, for stimulating hormone receptors, and by this, mimic the hormonal functions. Lectins can influence phagocytosis and movement of the cells as well as the cell division. As Tetrahymena can recognize both related and hostile cells by the help of lectins and surface sugars, it could be surmised a complex predator-prey system. This could determine the survival of the population as well as the nourishment conditions. When Tetrahymena is pathogenic, it can use lectins as virulence factors.

Section: Discussionmentioning

confidence: 99%

Lectins and Tetrahymena – A review

Acta Microbiologica et Immunologica Hungarica

2016

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“…Unicellulars (Tetrahymena) show the general adaptation syndrome, which was the basis of stress theory by Selye [64,65], giving a general response to stressors [66][67][68]. It seems to be likely that hormetic effects can influence the process and this could have a role in the evolutionary adaptation to toxic impacts [69].…”

Section: Discussionmentioning

confidence: 99%

Provocation of life functions at a unicellular eukaryote level by extremely low doses of mammalian hormones: Evidences of hormesis

2019

AMicr

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Hormones, characteristic to higher ranked animals, are synthesized, stored, and secreted by unicellular eukaryote animals. The unicells also have receptors for recognizing these materials and transmit the message into the cells for provoking response. The hormones are effective in very low concentrations (down to 10–21 M) and opposite effects of lower and higher concentrations can be observed. However, sometimes linear concentration effects can be found, which means that hormesis exists, nevertheless uncertain, as it is in the phase of formation (evolutionary experimentation). Hormesis, by transformation (fixation) of cytoplasmic receptor-like membrane components to receptors in the presence of the given hormone, likely helps the development of unicellular endocrine character and by this the evolution of endocrine system. The effect by extremely low concentrations of hormones had been forced by the watery way of unicellular life, which could establish the physiological concentrations of hormones in the blood of higher ranked animals. This means that hormetic low doses are the normal, effective concentrations and the high concentrations are artificial, consequently could be dangerous.

“…However, hormones are synthesized, stored, and secreted by unicells which can influence phagocytosis [99,100] and there is a similar situation in multicells, where hormones which has specific functions (e.g., regulation of sugar metabolism, blood calcium level, ovarian cycle, etc.) are also influencing the phagocytosis of professional cells (macrophages and neutrophil granulocytes).…”

Section: Discussionmentioning

confidence: 99%

Is there a hormonal regulation of phagocytosis at unicellular and multicellular levels? A critical review

2017

AMicr

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Phagocytosis is an ancient cell function, which is similar at unicellular and multicellular levels. Unicells synthesize, store, and secrete multicellular (mammalian) hormones, which influence their phagocytosis. Amino acid hormones, such as histamine, serotonin, epinephrine, and melatonin stimulate phagocytosis, whereas peptide hormones, such as adrenocorticotropic hormone (ACTH), insulin, opioids, arginine vasopressin, and atrial natriuretic peptide decreased it, independently on their chemical structure or function in multicellulars. Macrophage phagocytosis of multicellulars is also stimulated by amino acid hormones, such as histamine, epinephrine, melatonin, and thyroid hormones, however, the effect of peptide hormones is not uniform: prolactin, insulin, glucagon, somatostatin, and leptin have positive effects, whereas ACTH, human chorionic gonadotropin, opioids, and ghrelin have negative ones. Steroid hormones, such as estrogen, hydrocortisone, and dexamethasone are stimulating macrophage phagocytosis, whereas progesterone, aldosterone, and testosterone are depressing it. Considering the data and observations there is not a specific phagocytosis hormone, or a hormonal regulation of phagocytosis neither unicellular, nor multicellular level, however, hormones having specific functions in multicellulars also influence phagocytosis at both levels universally (in unicellulars) or individually (in macrophages). Nevertheless, the hormonal influence cannot be neglected, as phagocytosis (as a function) is rather sensitive to minute dose of hormones and endocrine disruptors. The hormonal influence of phagocytosis by macrophages can be deduced to the events at unicellular level.