From the retina of the land-locked population of the sea lamprey, Petromyzon marinus, a photolabile pigment was extracted which was identified spectrophotometrically as a member of the rhodopsin group of pigments. Using the absorption spectrum of a relatively pure solution and analysis by means of difference spectra, the peak of this pigment was placed at about 497 mmicro. The method of selecti...

The hypothalamic-pituitary system is considered to be a vertebrate innovation and seminal event that emerged prior to or during the differentiation of the ancestral agnathans. Lampreys are the earliest evolved vertebrates for which there is a demonstrated neuroendocrine system. Lampreys have three hypothalamic gonadotropin-releasing hormones (GnRHs; lGnRH-I, -II, and -III) and two and possibly ...

Mammals contain 1 melanopsin (Opn4) gene that is expressed in a subset of retinal ganglion cells to serve as a photopigment involved in non-image-forming vision such as photoentrainment of circadian rhythms. In contrast, most nonmammalian vertebrates possess multiple melanopsins that are distributed in various types of retinal cells; however, their functions remain unclear. We previously found ...

Caspian sea is a land–locked brackish water lake where zoologically characterized by various aquatic animals aquatic animals and different commercially important fish species Shariati [15]. The fishes in the Caspian Sea and its watershed areas include 78 species, and 49 subspecies which belong to 16 fish family. The bulk of Caspian Sea fishes are anadromos and the major commercially important f...

Cut-to-length (CTL) timber harvesting technology currently accounts for approximately 90% of Caspian forests. The technology involves felling, branching, cross-cutting, and then the skidder carries the logs to a landing, where the timber is temporarily stored, sorted and assembled for transportation to the mill. Cut-to-length systems typically require less labor, less access road construction, ...

Cut-to-length (CTL) timber harvesting technology currently accounts for approximately 90% of Caspian forests. The technology involves felling, branching, cross-cutting, and then the skidder carries the logs to a landing, where the timber is temporarily stored, sorted and assembled for transportation to the mill. Cut-to-length systems typically require less labor, less access road construction, ...

Cut-to-length (CTL) timber harvesting technology currently accounts for approximately 90% of Caspian forests. The technology involves felling, branching, cross-cutting, and then the skidder carries the logs to a landing, where the timber is temporarily stored, sorted and assembled for transportation to the mill. Cut-to-length systems typically require less labor, less access road construction, ...

Elucidation of genetic mechanisms underpinning migratory behavior could help predict how changes in genetic diversity may affect future spatiotemporal distribution of a migratory species. This ability would benefit conservation of one such declining species, anadromous Pacific lamprey (Entosphenus tridentatus). Nonphilopatric migration of adult Pacific lamprey has homogenized population-level n...

The sea lamprey is an important model organism for investigating the evolutionary origins of vertebrates. As more vertebrate genome sequences are obtained, evolutionary developmental biologists are becoming increasingly able to identify putative gene regulatory elements across the breadth of the vertebrate taxa. The identification of these regions makes it possible to address how changes at the...

Lampreys, a jawless vertebrate species, lack not only jaws but also several other organs, including ventral migratory muscles shared by gnathostomes. In the lamprey embryo, the mesoderm consists primarily of unsegmented head mesoderm, segmented somites, and yet uncharacterized lateral plate mesoderm, as in gnathostomes. Although the adult lamprey possesses segmented myotomes in the head, the he...