Olfactory Rosette Research Articles

Structure and function of the olfactory apparatus in the fresh-water carp, Labeo rohita ham. buch.

The oval olfactory rosette of the carp Labeo rohita belongs to Burne's ('09) rosette column one or to Bateson's (1889) rosette type three. The total olfactory area of the fish is greater than its total retinal area; however, it has been classified with Teichmann's ('54) group of eye-nose fishes. Each olfactory chamber communicates with an anterior, ventral accessory sac; in spite of Burne's ('09) observation that accessory sacs are absent in carps. Movements of the jaw bones dilate and compress the accessory sac. Water is drawn in through the posterior opening (and not through the anterior as suggested by Liermann, '33, and Johnson and Brown, '62) and also expelled through it when the mouth opens and closes for normal respiratory function. Hence, the accessory sac does not draw water across the olfactory rosette through the anterior opening. At intervals, the fish opens its mouth full and wide and draws water into the chamber through the anterior opening as well.

The olfactory epithelium of the lantern fish, Tarletonbeania crenularis (Myctophidae).

The olfactory rosettes of Tarletonbeania crenularis are contained within paired membranous olfactory chambers opening to the exterior through a pair of nostrils. The margins of the anterior nostril form an infundibulum that may direct a current of water between the lamellae of the olfactory rosette and out of the posterior nostril as the fish swims through the water. The number of lamellae in a rosette is variable, and each consists of an olfactory epithelium containing receptor cells, supporting cells, basal cells, mucus cells and bipolar neurons. The olfactory surface for the most part is nonciliated and appears rugose in scanning electron micrographs. Receptor elements are located along the central axis of the rosette and on the surfaces of the distal margins of the lamellae.

Secondary Folding of Olfactory Organ in Young and Adult Sea Trout

The development of the olfactory rosette in parr, smolt and adult sea trout is investigated by means of different fixation and staining techniques. The rosette consists of primary laminae which are folded in four types of secondary laminae. These are here called initial, cuneiform, filiform and fungiform laminae. At least initially secondary folding seems to be an interplay between a blood capillary and the sensory epithelium external to it. The ecological adaptations of folded olfactory organs are discussed.

Scanning electron microscopy of olfactory rosette in sea trout.

Scanning electron microscopy has been employed to study the central axis and laminae of the olfactory rosette in adult sea trout (Salmo trutta trutta L.) caught in the River Umealven when they were homing from sea.—Both flat sides of the primary laminae are secondarily folded all over their surface. In one organ there are about 200 secondary laminae usually arranged in longitudinal, parallel ridges crossing the surface of the primary laminae. Initially they are covered with sensory epithelium, but as the folds grow they become covered with an increasing area of indifferent ciliar epithelium with bushes of cilia separated by microvilli cells and goblet cells. Parts of the central axis and primary laminae have a nonciliar indifferent epithelium. The sensory epithelium has irregularly arranged cilia. Like those of the indifferent epithelium they have uniform thickness and granulated surface. The function of laminae, secretion and cilia is discussed.

Comparative morphology of the cottid genus Myoxocephalus based on meristic, morphometric, and other anatomical characters

Specimens representing 15 nominal species of the genus Myoxocephalus were subjected to detailed comparative morphological study to determine some of the more important species characteristics and also those indicating potential for expressing phylogenetic progression.Analysis of seven meristic characters revealed that none of them is consistently sexually dependent. Geographic variation within the species indicated the presence of both latitudinal and longitudinal clines. No evolutionary group affinities were evident.The morphology of the cephalic lateral line system, lateral line ossicles, squamation, and olfactory rosettes were found to exhibit a high degree of specificity, especially the first three systems. With the exception of the lateral line ossicles all evidenced some potential as indicators of phylogeny.Analysis of 23 morphometric characters was accomplished by cluster analysis. The resultant clusters indicated heterogenous unnatural groupings.On the basis of these analyses well-defined species differences exist in most of the major morphological features. The nominal species M. scorpius (Linnaeus) includes three distinct species (Gulf of Alaska, Arctic–East coast, and European). In addition, the data indicate that the genus is probably composed of three basic evolutionary lines: the Holarctic–Atlantic, Bering Sea–Transpacific, and Asiatic.

Isolation of pregn-4-ene-17α, 20β-diol-3-one from the plasma of pacific salmon ( [formula omitted], [formula omitted

Our previous studies suggested that 17α,20β-dihydroxy-4-pregnen-3-one (DHP), an oocyte maturation inducing progestin, also acts as a sex pheromone in Chinese black sleeper Bostrichthys sinensis, a fish species that inhabits intertidal zones and mates and spawns inside a muddy burrow. The electro-olfactogram response to DHP increased during the breeding season. In the present study, we cloned the cDNAs of the nine progestin receptors (pgr, paqr5, 6, 7(a, b), 8, 9, pgrmc1, 2) from B. sinensis, analyzed their tissue distribution, and determined the expression in the olfactory rosette during the reproductive cycle in female and male fish. The deduced amino acid sequences of the nine progestin receptors share high sequence identities with those of other fish species and relatively lower homology with their mammalian counterparts, and phylogenetic analyses classified the nine B. sinensis progestin receptors into their respective progestin receptor groups. Tissue distribution of B. sinensis progestin receptors showed differential expression patterns, but all these nine genes were expressed in the olfactory rosette. Interestingly, paqr5 mRNA was found in the intermediate and basal parts of the olfactory epithelium but not in the central core using in situ hybridization, and its expression level was the highest in the olfactory rosette among the tissues examined. These results suggested Paqr5 may have an important role for transmitting progestin signaling in the olfactory system. The expression levels of paqr7a and paqr7b, pgr and pgrmc2 mRNA peaked around the mid meiotic stage, and that of paqr8 peaked at late meiotic stage in the olfactory rosette in males, while the olfactory expression of paqr5 decreased gradually as spermatogenesis progressed. In contrast, the expression of the progestin receptors did not change significantly during the development of the ovary in the olfactory rosette in females, except that of pgr. Interestingly, the changes of paqr8 expression in the olfactory rosette in males mirrored the changes of plasma DHP levels in females during the reproductive cycle, suggesting the Paqr8 may also be important for deciphering progestin signaling released by female. To our knowledge, this is the first time to demonstrate the presence of all known progestin receptors in a teleost olfactory rosette, and to show different expressions between the males and females during the reproductive cycle. This study provides the first evidence on changes of all purported progestin receptors during a reproductive cycle in teleost olfactory rosette, and suggests that distinct olfactory sensitivities to DHP may be due to the changes and compositions of each progestin receptor in B. sinensis.