• Fisheries and Aquatic Sciences
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• v.15 no.1
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• pp.63-67
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• 2012

A comparative study of bile acid components from four lamprey species revealed that mature male chestnut lamprey Ichthyomyzon castaneus can produce 3 keto petromyzonol sulfate (3kPZS) while mature males of Pacific lamprey Lampetra tridentata, river lamprey Lampetra fluviatilis and American brook lamprey Lethenteron appendix produce petromyzonol sulfate (PZS). Identification of 3kPZS from a group of ancient lamprey species and of PZS from recently derived species led to a speculation that differentiation of bile acid biosynthetic systems has taken place during the course of evolution. Further studies on the biological functions of different bile acids in the adult lampreys are required to understand the evolution of chemical communication in lampreys.

• Journal of Photoscience
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• v.9 no.2
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• pp.21-24
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• 2002

Pineal organs of poikilotherm vertebrates transform the environmental light information into a humoral message and a neuronal activity. The former is melatonin, and the latter is modulation of the impulse in ganglion cells. The ganglion cells are physiologically classified into luminosity (achromatic) type and chromatic one, as the neural activity is modulated in two ways. We attempted to classify the pineal ganglion cells with morphological characteristics by means of the three- dimensional reconstruction method. In the pineal ganglion cells of river lamprey, there are two different features, oval and spherical. For comparison of their projection region in the brain, the tracing investigation was also carried out. The application of the neural tracer near mesencephalic tegmentum showed that only oval-shaped ganglion cells were labeled in the pineal organ. These results suggest that the oval-shaped ganglion cell is functionally different from the spherical one.

• Proceedings of the Korean Aquaculture Society Conference
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• 2006.05a
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• pp.572-573
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• 2006

• 한국전자현미경학회:학술대회논문집
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• 1995.06a
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• pp.11-11
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• 1995

• Journal of Food Hygiene and Safety
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• v.4 no.2
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• pp.133-153
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• 1989

The present study was carried out to investigate the preventive effects of lamprey oil and corn oil on atherosclerotic rats induced by oral administration of cholesterol and vitamin $D_2$. The obtaind results were summarized as fellows; 1. The group, fed only the mixture of cholesterol and vitamin $D_2$ showed the significant increase of total lipid, total cholesterol phospholipid, LDL&HDL-cholesterol in the serum, triglyceride and cholesterol in the heart and the aorta, but the significant decrease of triglyceride in the liver, as comparing with normal control group (p<0.05). The aorta showed the severe damage of disorganization, calcification, necrosis and lipid deposition in the aortic wall. 2. The group, adminstered the mixture of cholesterol and vitamin $D_2$ and fed 15% lamprey oil diet, showed the significant decrease of total lipid, triglyceride, total cholesterol, phospholipid and LDL&VLDL-cholesterol in the serum, triglyceride and cholesterol in the heart and the aorta, but the significant increase of cholesterol in the liver, as comparing with atherogenic control group (p<0.05). The aorta showed slight calcification and no lipid deposition in the aortic wall as comparing with atherogenic control group. 3. The group, administerd the mixture of cholesterol and vitamin $D_2$ and fed 15% corn oil diet, showed the decrease of total lipid, triglyceride and VLDL-cholesterol in the serum, and triglyceride in the heart and the aorta, as comparing with atherogenic control group (p<0.05). The aorta showed calcification and no lipid deposition in the aortic wall. In reviewing above results it was concluded that lamprey oil and corn oil in polyunsaturated fatty acids had the preventive effect on atherosclerotic rats induced by cholesterol and vitamin $D_2$. And the effect of lamprey oil in n-3 polyunsaturated fatty acids was higher than that of corn oil rich in n-6 polyunsturated fatty acids.

• Smart Structures and Systems
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• v.8 no.1
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• pp.39-52
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• 2011

We are developing a biomimetic robot based on the Sea Lamprey. The robot consists of a cylindrical electronics bay propelled by an undulatory body axis. Shape memory alloy (SMA) actuators generate propagating flexion waves in five undulatory segments of a polyurethane strip. The behavior of the robot is controlled by an electronic nervous system (ENS) composed of networks of discrete-time map-based neurons and synapses that execute on a digital signal processing chip. Motor neuron action potentials gate power transistors that apply current to the SMA actuators. The ENS consists of a set of segmental central pattern generators (CPGs), modulated by layered command and coordinating neuron networks, that integrate input from exteroceptive sensors including a compass, accelerometers, inclinometers and a short baseline sonar array (SBA). The CPGs instantiate the 3-element hemi-segmental network model established from physiological studies. Anterior and posterior propagating pathways between CPGs mediate intersegmental coordination to generate flexion waves for forward and backward swimming. The command network mediates layered exteroceptive reflexes for homing, primary orientation, and impediment compensation. The SBA allows homing on a sonar beacon by indicating deviations in azimuth and inclination. Inclinometers actuate a bending segment between the hull and undulator to allow climb and dive. Accelerometers can distinguish collisions from impediment to allow compensatory reflexes. Modulatory commands mediate speed control and turning. A SBA communications interface is being developed to allow supervised reactive autonomy.

• Applied Microscopy
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• v.50
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• pp.18.1-18.7
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• 2020

The olfactory anatomy and histology of Lethenteron reissneri were researched using a stereo microscope, a light microscope, and a scanning electron microscope. As in other lampreys, it shows same characters as follows: i) a single olfactory organ, ii) a single tubular nostril, iii) a single olfactory chamber with gourd-like form, iv) a nasal valve, v) a nasopharyngeal pouch, vi) a sensory epithelium (SE) of continuous distribution, vii) a supporting cells with numerous long cilia, viii) an accessory olfactory organ. However, the description of a pseudostratified columnar layer in the SE and Non SE is a first record, not reported in sea lamprey Petromyzon marinus. In particular, both 19 to 20 lamellae in number and olfactory receptor neuron's quarter ciliary length of the knob diameter differ from those of P. marinus. From these results, it might be considered that the olfactory organ of L. reissneri shows well adaptive structure of a primitive fish to slow flowing water with gravel, pebbles, and sand and a hiding habit into sand bottom at daytime. The lamellar number and neuron's ciliary length may be a meaningful taxonomic character for the class Petromyzonida.

• Korean Journal of Ichthyology
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• v.2 no.2
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• pp.149-158
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• 1990

The brook lamprey, Lampetra reissneri, was collected from an branch of the Nakdong River (Namwon-gun, Chollabuk-Do) and the Seomjin River (Hadong-Gun, Kyungsangnam-Do) from September, 1989 to April, 1990. Specimens were 95 individuals in number and composed of 21 ammocoetes, 16 metamorphosing animals and 58 adults which do not exceed 200mm in total length. The modal numbers of trunk myomer was 57.5, ranged from 55 to 60. In the dental formula, the supraoral tooth consistently had 2 cusps, and lateral circumorals were 3 in each side with 2 cusps. The infraoral had varying numbers of cusps ranging from 6 to 8. In morphological measurement of adults, prebranchial length was 10.3%, branchial length 9.7%, trunk length 51.3% and tail length 28.3% respectively, in hundreds of total length. No significant differences in morphological characteristics were observed between the two populations studied.

• Journal of fish pathology
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• v.26 no.1
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• pp.39-44
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• 2013

Saprolegnia isolate from wild brook lamprey was identified on the basis of its morphological and molecular characteristics. The isolates showed aseptic hyphae and clavate zoosporagium. Zoospores discharge was typically saprolegnoid. Neither oogomia nor antheridia was observed in this study. ITS sequence obtained from the isolate was compared with other Saprolegnia spp. to analyse their phylogenetic relationships. Results showed that the isolate belongs to clade I including Saprolegnia parasitica. Based on the asexual organs, zoospore discharge manner and ITS sequence analysis, the isolate was identified as S. parasitica.

• Korean Journal of Ichthyology
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• v.4 no.2
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• pp.77-81
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• 1992

Chromosome numbers of 3 species of Korea lampreys(Genus Lampetra) were investigated. Approximately 160 small and mainly acrocentric chromsomes were present in the three species of Korean lampreys. And the diploid chromosome numbers of three species were not significantly different between the species.