Coturnix

About: Coturnix is a(n) research topic. Over the lifetime, 953 publication(s) have been published within this topic receiving 23305 citation(s).

Hair cell regeneration after acoustic trauma in adult Coturnix quail.

Abstract: Recovery of hair cells was studied at various times after acoustic trauma in adult quail. An initial loss of hair cells recovered to within 5 percent of the original number of cells. Tritium-labeled thymidine was injected after this acoustic trauma to determine if mitosis played a role in recovery of hair cells. Within 10 days of acoustic trauma, incorporation of [3H]thymidine was seen over the nuclei of hair cells and supporting cells in the region of initial hair cell loss. Thus, hair cell regeneration can occur after embryonic terminal mitosis.

Thyrotrophin in the pars tuberalis triggers photoperiodic response

Abstract: Molecular mechanisms regulating animal seasonal breeding in response to changing photoperiod are not well understood. Rapid induction of gene expression of thyroid-hormone-activating enzyme (type 2 deiodinase, DIO2) in the mediobasal hypothalamus (MBH) of the Japanese quail (Coturnix japonica) is the earliest event yet recorded in the photoperiodic signal transduction pathway. Here we show cascades of gene expression in the quail MBH associated with the initiation of photoinduced secretion of luteinizing hormone. We identified two waves of gene expression. The first was initiated about 14 h after dawn of the first long day and included increased thyrotrophin (TSH) beta-subunit expression in the pars tuberalis; the second occurred approximately 4 h later and included increased expression of DIO2. Intracerebroventricular (ICV) administration of TSH to short-day quail stimulated gonadal growth and expression of DIO2 which was shown to be mediated through a TSH receptor-cyclic AMP (cAMP) signalling pathway. Increased TSH in the pars tuberalis therefore seems to trigger long-day photoinduced seasonal breeding.

Tracing of cells of the avian thymus through embryonic life in interspecific chimeras.

Abstract: Differences in the structure of the interphase nucleus between two species of birds, the Japanese quail (Coturnix coturnix japonica) and the chick (Gallus gallus) has been used to distinguish cells from different origins in interspecies combinations. This biological cell marking technique was applied to thymus histogenesis. Using various combinations between components of quail and chick thymic rudiments, the respective contribution of endodermal epithelium, mesenchyme, and blood-borne extrinsic elements to the histogenesis of thymus was analyzed. It was demonstrated that the whole lymphoid population of the thymus is derived from immigrant blood-borne stem cells which are chemically attracted by the endoderm of the 3rd and 4th pharyngeal pouch. The latter is determined to differentiate into thymic epithelial reticulum as soon as the 15-somite stage, and is able to attract blood stem cells even when transplanted in an heterotopic position such as the ventral body wall of the embryo. It was shown that the thymic mesenchyme originates from the neural crest mesectoderm which colonizes early the 3rd and 4th branchial arches. It participates in the formation of perivascular mesenchyme, but does not give rise to lymphocytes. From heterospecific transplantations of quail thymuses into chick embryo (and inversely) at various stages of development is appeared that the thymic rudiment becomes attractive for lymphoid stem cells at a precise stage of its evolution for each species. The attractivity period lasts about 24 h for the quail and 36 h for the chick. Then, the inflow of stem cells becomes very low until the end of the incubation period. At this time, a second wave of lymphocytoblasts invades the thymus and the primitive embryonic lymphoid population is completely renewed around the hatching time. Competent thymic stem cells are present in the blood before and after the period of physiological thymic attractivity. The identity of basophilic cells appearing in the thymus during its histogenesis and lymphoid stem cells has been demonstrated from the analysis of quail-chick chimeric thymuses.

Toxicokinetics of ochratoxin A in several species and its plasma-binding properties.

Abstract: The toxicokinetic profile of ochratoxin A was studied after the oral or intravenous administration of 50 ng/g b.w. to fish, quail, mouse, rat and monkey. The elimination half-life varied from 0.68 h after oral administration to fish, up to 840 h after intravenous administration to monkey. The distribution volume ranged from 57 ml/kg in fish to 1500 ml/kg in quail. The plasma clearance was most rapid in quail and fish, 72 and 58 ml/kg.h, respectively, while it was only 0.17 ml/kg.h in monkey. The bioavailability was as low as 1.6% in fish but as high as 97% in mouse. The binding abilities of ochratoxin A to plasma proteins were also studied. From these data we calculated the free fraction of toxin in plasma, which we found to be less than 0.2% in all species investigated (including man) except fish. A similar but smaller investigation on the toxicokinetics and binding properties of ochratoxin B was also performed. Ochratoxin B was more readily eliminated and had a lower affinity for plasma proteins, which partly may explain its lower toxicity.