scholarly journals Roles of Direct Photoreception and the Internal Circadian Oscillator in the Regulation of Melatonin Secretion in the Pineal Organ of the Domestic Turkey: A Novel In Vitro Clock and Calendar Model

2019 ◽  
Vol 20 (16) ◽  
pp. 4022 ◽  
Author(s):  
Magdalena Prusik ◽  
Bogdan Lewczuk
Keyword(s):  
Pineal Organ ◽  
High Amplitude ◽  
Attractive Alternative ◽  
Melatonin Secretion ◽  
Continuous Darkness ◽  
Light Pulses ◽  
Acting Mechanism ◽  
Internal Oscillator ◽  
D 12

The regulation of melatonin secretion in the avian pineal organ is highly complex and shows prominent interspecies differences. The aim of this study was to determine the roles of direct photoreception and the internal oscillator in the regulation of melatonin secretion in the pineal organ of the domestic turkey. The pineal organs were collected from 12-, 13- and 14-week-old female turkeys reared under a 12 L:12 D cycle with the photophase from 07.00 to 19.00, and were incubated in superfusion culture for 3–6 days. The cultures were subjected to different light conditions including 12 L:12 D cycles with photophases between 07.00 and 19.00, 13.00 and 01.00 or 01.00 and 13.00, a reversed cycle 12 D:12 L, cycles with long (16 L:8 D) and short (8 L:16 D) photophases, and continuous darkness or illumination. The pineal organs were also exposed to light pulses of variable duration during incubation in darkness or to periods of darkness during the photophase. The secretion of melatonin was determined by direct radioimmunoassay. The turkey pineal organs secreted melatonin in a well-entrained diurnal rhythm with a very high amplitude. Direct photoreception as an independently acting mechanism was able to ensure quick and precise adaptation of the melatonin secretion rhythm to changes in light-dark conditions. The pineal organs secreted melatonin in circadian rhythms during incubation in continuous darkness or illumination. The endogenous oscillator of turkey pinealocytes was able to acquire and store information about the light-dark cycle and then to generate the circadian rhythm of melatonin secretion in continuous darkness according to the stored data. The obtained data suggest that the turkey pineal gland is highly autonomous in the generation and regulation of the melatonin secretion rhythm. They also demonstrate that the turkey pineal organ in superfusion culture is a valuable model for chronobiological studies, providing a highly precise clock and calendar. This system has several features which make it an attractive alternative to other avian pineal glands for circadian studies.

Regulation of melatonin secretion in the pineal organ of the domestic duck – an in vitro study

2015 ◽  
Vol 18 (3) ◽  
pp. 635-644 ◽  
Author(s):  
M. Prusik ◽  
B. Lewczuk ◽  
N. Ziółkowska ◽  
B. Przybylska-Gornowicz
Keyword(s):  
Pineal Organ ◽  
Continuous Light ◽  
In Vitro Study ◽  
Secretory Activity ◽  
High Amplitude ◽  
Diurnal Changes ◽  
Light Cycle ◽  
Melatonin Secretion ◽  
Dark Cycle

AbstractThe aim of study was to determine the mechanisms regulating melatonin secretion in the pineal organs of 1-day-old and 9-month-old domestic ducks. The pineals were cultured in a superfusion system under different light conditions. Additionally, some explants were treated with norepinephrine.The pineal glands of 1-day-old ducks released melatonin in a well-entrained, regular rhythm during incubation under a 12 hrs light : 12 hrs dark cycle and adjusted their secretory activity to a reversed 12 hrs dark : 12 hrs light cycle within 2 days. In contrast, the diurnal changes in melatonin secretion from the pineals of 9-month-old ducks were largely irregular and the adaptation to a reversed cycle lasted 3 days. The pineal organs of nestling and adult ducks incubated in a continuous light or darkness secreted melatonin in a circadian rhythm. The treatment with norepinephrine during photophases of a light-dark cycle resulted in: 1) a precise adjustment of melatonin secretion rhythm to the presence of this catecholamine in the culture medium, 2) a very high amplitude of the rhythm, 3) a rapid adaptation of the pineal secretory activity to a reversed light-dark cycle. The effects of norepinephrine were similar in the pineal organs of nestlings and adults.In conclusion, melatonin secretion in the duck pineal organ is controlled by three main mechanisms: the direct photoreception, the endogenous generator and the noradrenergic transmission. The efficiency of intra-pineal, photosensitivity-based regulatory mechanism is markedly lower in adult than in nestling individuals.

scholarly journals Regulation of melatonin secretion in a photoreceptive pineal organ: an in vitro study in the pike

1989 ◽  
Vol 9 (6) ◽  
pp. 1943-1950 ◽  
Author(s):  
J Falcon ◽  
JB Marmillon ◽  
B Claustrat ◽  
JP Collin
Keyword(s):  
Pineal Organ ◽  
In Vitro Study ◽  
Vitro Study ◽  
Melatonin Secretion

Benzodiazepines influence melatonin secretion of the pineal organ of the trout in vitro

1994 ◽  
Vol 17 (2) ◽  
pp. 69-78 ◽  
Author(s):  
Hilmar Meissl ◽  
Julián Yáñez ◽  
Peter Ekström ◽  
Eberhard Grossmann
Keyword(s):  
Pineal Organ ◽  
Melatonin Secretion

scholarly journals Modified Gold Nanoparticles for Efficient Delivery of Betulinic Acid to Cancer Cell Mitochondria

2021 ◽  
Vol 22 (10) ◽  
pp. 5072
Author(s):  
Olakunle Oladimeji ◽  
Jude Akinyelu ◽  
Aliscia Daniels ◽  
Moganavelli Singh
Keyword(s):  
Polyethylene Glycol ◽  
Cancer Cell ◽  
Betulinic Acid ◽  
Targeted Delivery ◽  
Epigallocatechin Gallate ◽  
High Amplitude ◽  
Significant Inhibition ◽  
Mitochondrial Targeting ◽  
The Impact

Advances in nanomedicine have seen the adaptation of nanoparticles (NPs) for subcellular delivery for enhanced therapeutic impact and reduced side effects. The pivotal role of the mitochondria in apoptosis and their potential as a target in cancers enables selective induction of cancer cell death. In this study, we examined the mitochondrial targeted delivery of betulinic acid (BA) by the mitochondriotropic TPP+-functionalized epigallocatechin gallate (EGCG)-capped gold NPs (AuNPs), comparing the impact of polyethylene glycol (PEG) and poly-L-lysine-graft-polyethylene glycol (PLL-g-PEG) copolymer on delivery efficacy. This included the assessment of their cellular uptake, mitochondrial localization and efficacy as therapeutic delivery platforms for BA in the human Caco-2, HeLa and MCF-7 cancer cell lines. These mitochondrial-targeted nanocomplexes demonstrated significant inhibition of cancer cell growth, with targeted nanocomplexes recording IC50 values in the range of 3.12–13.2 µM compared to that of the free BA (9.74–36.31 µM) in vitro, demonstrating the merit of mitochondrial targeting. Their mechanisms of action implicated high amplitude mitochondrial depolarization, caspases 3/7 activation, with an associated arrest at the G0/G1 phase of the cell cycle. This nano-delivery system is a potentially viable platform for mitochondrial-targeted delivery of BA and highlights mitochondrial targeting as an option in cancer therapy.

scholarly journals Light Cross-Linkable Marine Collagen for Coaxial Printing of a 3D Model of Neuromuscular Junction Formation

Biomedicines ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 16
Author(s):  
Borja Sanz ◽  
Ane Albillos Sanchez ◽  
Bonnie Tangey ◽  
Kerry Gilmore ◽  
Zhilian Yue ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Neuromuscular Junction ◽  
Disease Transmission ◽  
Low Cost ◽  
Attractive Alternative ◽  
Waste Products ◽  
Environmentally Sustainable ◽  
Zoonotic Disease Transmission ◽  
And Migration

Collagen is a major component of the extracellular matrix (ECM) that modulates cell adhesion, growth, and migration, and has been utilised in tissue engineering applications. However, the common terrestrial sources of collagen carry the risk of zoonotic disease transmission and there are religious barriers to the use of bovine and porcine products in many cultures. Marine based collagens offer an attractive alternative and have so far been under-utilized for use as biomaterials for tissue engineering. Marine collagen can be extracted from fish waste products, therefore industry by-products offer an economical and environmentally sustainable source of collagen. In a handful of studies, marine collagen has successfully been methacrylated to form collagen methacrylate (ColMA). Our work included the extraction, characterization and methacrylation of Red Snapper collagen, optimisation of conditions for neural cell seeding and encapsulation using the unmodified collagen, thermally cross-linked, and the methacrylated collagen with UV-induced cross-linking. Finally, the 3D co-axial printing of neural and skeletal muscle cell cultures as a model for neuromuscular junction (NMJ) formation was investigated. Overall, the results of this study show great potential for a novel NMJ in vitro 3D bioprinted model that, with further development, could provide a low-cost, customizable, scalable and quick-to-print platform for drug screening and to study neuromuscular junction physiology and pathogenesis.

Effects of ghrelin on nocturnal melatonin secretion in sheep: An in vitro and in vivo approach1

2017 ◽  
Vol 95 (9) ◽  
pp. 4101-4112
Author(s):  
K. Kirsz ◽  
M. Szczesna ◽  
E. Molik ◽  
D. A. Zieba
Keyword(s):  
Melatonin Secretion

scholarly journals Agrobacterium-mediated transformation of the wild orchid Cattleya maxima Lindl

2018 ◽  
Vol 23 (1) ◽  
pp. 89
Author(s):  
Augusta Yadira Cueva-Agila ◽  
Rino Cella
Keyword(s):  
Somatic Embryogenesis ◽  
Somatic Embryos ◽  
Attractive Alternative ◽  
Gene Encoding ◽  
Anatomical Structures ◽  
Large Numbers ◽  
Hygromycin Resistance Gene ◽  
Growing Conditions ◽  
Somatic Embryogenesis Receptor Kinase

Protocorms are unique anatomical structures; they are akin to rhizoids and are formed by young orchid seedlings under physiological conditions. Explanted orchid tissues produce similar structures called protocorm-like bodies (PLBs) when exposed to appropriate <em>in vitro</em> growing conditions. Both the propagative nature of PLBs and the easiness by which they can be generated, make these structures an attractive alternative to seed-mediated production for growing large numbers of plants. To increase somatic embryogenesis and optimize the procedure, PLBs of <em>Cattleya maxima </em>were transformed<em> </em>using the <em>Agrobacterium tumefaciens </em>method. The T-DNA carried a Hygromycin-resistance gene, a visible marker (GFP5-GUSA) and a rice gene encoding the Somatic Embryogenesis Receptor Kinase, deemed to be important for somatic embryogenesis. Treated PLBs generated somatic embryos developing Hygromycin-resistant plantlets. The insertion of T-DNA was confirmed by PCR, and GFP expression was observed using a fluorescent stereomicroscope. Transformed <em>Cattleya maxima</em> PLBs were more efficient in forming somatic embryos (60-80%) than untransformed controls (45-57%), and this contrast was maximized in hormone-free, Murashige and Skoog (MS) medium (80% of the transformed plants compared to 57% of the untransformed ones). This finding supports the notion that SERK<em> </em>plays an important role in Orchid embryogenesis.

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