Mucin-like glycoproteins have established roles in epithelial boundary protection and lubricative roles in some tissues.This mini-review illustrates alternative functional roles which rely on keratan sulphate and sial...Mucin-like glycoproteins have established roles in epithelial boundary protection and lubricative roles in some tissues.This mini-review illustrates alternative functional roles which rely on keratan sulphate and sialic acid modifications to mucin glycopolymers which convey charge properties suggestive of novel electroconductive properties not previously ascribed to these polymers.Many tumour cells express mucin-like glycopolymers modified with highly sulphated keratan sulphate and sialic which can be detected using diagnostic biosensors.The mucin-like keratan sulphate glycopolymer present in the ampullae of lorenzini is a remarkable sensory polymer which elasmobranch fish(sharks,rays,skate) use to detect weak electrical fields emitted through muscular activity of prey fish.Information on the proton gradients is conveyed to neuromast cells located at the base of the ampullae and mechanotransduced to neural networks.This ampullae keratan sulphate sensory gel is the most sensitive proton gradient detection polymer known in nature.This process is known as electrolocation,and allows the visualization of prey fish under conditions of low visibility.The bony fish have similar electroreceptors located along their lateral lines which consist of neuromast cells containing sensory hairs located within a cupula which contains a sensory gel polymer which detects distortions in fluid flow in channels within the lateral lines and signals are sent back to neural networks providing information on the environment around these fish.One species of dolphin,the Guiana dolphin,has electrosensory pits in its bill with similar roles to the ampullae but which have evolved from its vibrissal system.Only two terrestrial animals can undertake electrolocation,these are the Duck-billed platypus and long and short nosed Echidna.In this case the electrosensor is a highly evolved innervated mucous gland.The platypus has 40,000 electroreceptors around its bill through which it electrolocates food species.The platypus has poor eyesight,is a nocturnal feeder and closes its eyes,nostrils and ears when it hunts,so electrolocation is an essential sensory skill.Mammals also have sensory cells containing stereocilia which are important in audition in the organ of corti of the cochlea and in olfaction in the olfactory epithelium.The rods and cones of the retina also have an internal connecting cilium with roles in the transport of phototransduced chemical signals and activation of neurotransmitter release to the optic nerve.Mucin-like glycopolymer gels surround the stereocilia of these sensory hair cells but these are relatively poorly characterized however they deserve detailed characterization since they may have important functional attributes.展开更多
Instead of vision, many nocturnal animals use alternative senses for navigation and object detection in their dark environment. For this purpose, weakly electric mormyrid fish employ active electrolocation, during whi...Instead of vision, many nocturnal animals use alternative senses for navigation and object detection in their dark environment. For this purpose, weakly electric mormyrid fish employ active electrolocation, during which they discharge a specialized electric organ in their tail which discharges electrical pulses. Each discharge builds up an electrical field around the fish, which is sensed by cutaneous electroreceptor organs that are distributed over most of the body surface of the fish. Nearby objects distort this electrical field and cause a local alteration in current flow in those electroreceptors that are closest to the object. By constandy monitoring responses of its electroreceptor organs, a fish can detect, localize, and identify environmental objects. Inspired by the remarkable capabilities of weakly electric fish in detecting and recognizing objects, we designed technical sensor systems that can solve similar problems of remote object sensing. We applied the principles of active electrolocation to technical systems by building devices that produce electrical current pulses in a conducting medium （water or ionized gases） and simultaneously sense local current density. Depending on the specific task a sensor was designed for devices could （i） detect an object, （ii） localize it in space, （iii） determine its distance, and （iv） measure properties such as material properties, thickness, or material faults. Our systems proved to be relatively insensitive to environmental disturbances such as heat, pressure, or turbidity. They have a wide range of applications including material identification, quality control, non-contact distance measurements, medical applications and many more. Despite their astonishing capacities, our sensors still lag far behind what electric fish are able to achieve during active electrolocation. The understanding of the neural principles governing electric fish sensory physiology and the corresponding optimization of our sensors to solve certain technical tasks therefore remain ongoing goals of our research.展开更多
Weakly electric fish has an ability to generate a low-frequency electric field actively to locate the surrounding object in complete darkness by sensing the change of the electric field. This ability is called active ...Weakly electric fish has an ability to generate a low-frequency electric field actively to locate the surrounding object in complete darkness by sensing the change of the electric field. This ability is called active electrolocation. In this paper, we designed a two-dimensional （2D） experimental platform of underwater active electrolocation system by simulating weakly electric fish. On the platform, location characteristics based on frequency domain were investigated. Results indicated that surface shape of 3D location characteristic curves for the 2D underwater active electrolocation positioning system was convex upwards or concave down which was influenced by the material of probed objects and the frequency of the electric field exci- tation signal. Experiments also confirmed that the amplitude of the electric field excitation signal and the size of the probed object will only influence the amplitude corresponding to 3D location characteristic curves. Based on above location charac- teristics, we present three location algorithms including Cross Location Algorithm （CLA）, Stochastic Location Algorithm （SLA） and Particle Swarm Optimization （PSO） location algorithm in frequency domain and achieved the task of the underwater positioning system. Our work may have reference value for underwater detection study.展开更多
基金supported by the National Health and Medical Research Council Project,No.1004032
文摘Mucin-like glycoproteins have established roles in epithelial boundary protection and lubricative roles in some tissues.This mini-review illustrates alternative functional roles which rely on keratan sulphate and sialic acid modifications to mucin glycopolymers which convey charge properties suggestive of novel electroconductive properties not previously ascribed to these polymers.Many tumour cells express mucin-like glycopolymers modified with highly sulphated keratan sulphate and sialic which can be detected using diagnostic biosensors.The mucin-like keratan sulphate glycopolymer present in the ampullae of lorenzini is a remarkable sensory polymer which elasmobranch fish(sharks,rays,skate) use to detect weak electrical fields emitted through muscular activity of prey fish.Information on the proton gradients is conveyed to neuromast cells located at the base of the ampullae and mechanotransduced to neural networks.This ampullae keratan sulphate sensory gel is the most sensitive proton gradient detection polymer known in nature.This process is known as electrolocation,and allows the visualization of prey fish under conditions of low visibility.The bony fish have similar electroreceptors located along their lateral lines which consist of neuromast cells containing sensory hairs located within a cupula which contains a sensory gel polymer which detects distortions in fluid flow in channels within the lateral lines and signals are sent back to neural networks providing information on the environment around these fish.One species of dolphin,the Guiana dolphin,has electrosensory pits in its bill with similar roles to the ampullae but which have evolved from its vibrissal system.Only two terrestrial animals can undertake electrolocation,these are the Duck-billed platypus and long and short nosed Echidna.In this case the electrosensor is a highly evolved innervated mucous gland.The platypus has 40,000 electroreceptors around its bill through which it electrolocates food species.The platypus has poor eyesight,is a nocturnal feeder and closes its eyes,nostrils and ears when it hunts,so electrolocation is an essential sensory skill.Mammals also have sensory cells containing stereocilia which are important in audition in the organ of corti of the cochlea and in olfaction in the olfactory epithelium.The rods and cones of the retina also have an internal connecting cilium with roles in the transport of phototransduced chemical signals and activation of neurotransmitter release to the optic nerve.Mucin-like glycopolymer gels surround the stereocilia of these sensory hair cells but these are relatively poorly characterized however they deserve detailed characterization since they may have important functional attributes.
文摘Instead of vision, many nocturnal animals use alternative senses for navigation and object detection in their dark environment. For this purpose, weakly electric mormyrid fish employ active electrolocation, during which they discharge a specialized electric organ in their tail which discharges electrical pulses. Each discharge builds up an electrical field around the fish, which is sensed by cutaneous electroreceptor organs that are distributed over most of the body surface of the fish. Nearby objects distort this electrical field and cause a local alteration in current flow in those electroreceptors that are closest to the object. By constandy monitoring responses of its electroreceptor organs, a fish can detect, localize, and identify environmental objects. Inspired by the remarkable capabilities of weakly electric fish in detecting and recognizing objects, we designed technical sensor systems that can solve similar problems of remote object sensing. We applied the principles of active electrolocation to technical systems by building devices that produce electrical current pulses in a conducting medium （water or ionized gases） and simultaneously sense local current density. Depending on the specific task a sensor was designed for devices could （i） detect an object, （ii） localize it in space, （iii） determine its distance, and （iv） measure properties such as material properties, thickness, or material faults. Our systems proved to be relatively insensitive to environmental disturbances such as heat, pressure, or turbidity. They have a wide range of applications including material identification, quality control, non-contact distance measurements, medical applications and many more. Despite their astonishing capacities, our sensors still lag far behind what electric fish are able to achieve during active electrolocation. The understanding of the neural principles governing electric fish sensory physiology and the corresponding optimization of our sensors to solve certain technical tasks therefore remain ongoing goals of our research.
基金This work was supported by the National Natural Science Foundation of China （Grant No. 61573083）.
文摘Weakly electric fish has an ability to generate a low-frequency electric field actively to locate the surrounding object in complete darkness by sensing the change of the electric field. This ability is called active electrolocation. In this paper, we designed a two-dimensional （2D） experimental platform of underwater active electrolocation system by simulating weakly electric fish. On the platform, location characteristics based on frequency domain were investigated. Results indicated that surface shape of 3D location characteristic curves for the 2D underwater active electrolocation positioning system was convex upwards or concave down which was influenced by the material of probed objects and the frequency of the electric field exci- tation signal. Experiments also confirmed that the amplitude of the electric field excitation signal and the size of the probed object will only influence the amplitude corresponding to 3D location characteristic curves. Based on above location charac- teristics, we present three location algorithms including Cross Location Algorithm （CLA）, Stochastic Location Algorithm （SLA） and Particle Swarm Optimization （PSO） location algorithm in frequency domain and achieved the task of the underwater positioning system. Our work may have reference value for underwater detection study.
