Mathematical description of the stimuli to the lateral line system of fish derived from a three-dimensional flow field analysis

The three-dimensional potential flow field around a moving fish with an axially symmetric body is investigated mathematically. The case of a moving fish in open water and that of one approaching a plane surface in front of it are considered. For these cases the spatial and temporal distributions of the stimuli to the lateral line system are derived from the flow field analysis. This is done in dependence on the shape and the size of the fish.     

The electrical response of the lateral line system of fish to tone and other stimuli

1. The lateral line of Fundulus heteroclitus and Fundulus majalis is shown to react to tone at an intensity level of 20 dynes per sq. cm. at frequencies up to 200 or 300 cycles per second. 2. Evidence is given that the nerve can reproduce the stimulating tone frequency up to at least 180 cycles per second. 3. The response of the lateral line to the swimming movements of nearby fish is demonstrated. 4. Fundulus and several other species are shown to give strong spontaneous activity of the lateral line nerve.     

Coping with flow: behavior, neurophysiology and modeling of the fish lateral line system

With the mechanosensory lateral line fish perceive water motions relative to their body surface and local pressure gradients. The lateral line plays an important role in many fish behaviors including the detection and localization of dipole sources and the tracking of prey fish. The sensory units of the lateral line are the neuromasts which are distributed across the surface of the animal. Water motions are received and transduced into neuronal signals by the neuromasts. These signals are conveyed by afferent nerve fibers to the fish brain and processed by lateral line neurons in parts of the brainstem, cerebellum, midbrain, and forebrain. In the cerebellum, midbrain, and forebrain, lateral line information is integrated with sensory information from other modalities. The present review introduces the peripheral morphology of the lateral line, and describes our understanding of lateral line physiology and behavior. It focuses on recent studies that have investigated: how fish behave in unsteady flow; what kind of sensory information is provided by flow; and how fish use and process this information. Finally, it reports new theoretical and biomimetic approaches to understand lateral line function.     

Mathematical analysis of an activation-inhibition system in a discrete field

The activation-inhibition model of Meinhardt and Gierer is investigated in the particular case of a stringlike set of cells. This reaction-diffusion system is considered, from a topical point of view, as a nonautonomous dynamic system which rules the behavior of each cell. It was shown that, when no diffusion occurs, this system can have either no or one or two stable steady states. The effect of intercellular exchanges on the existence and stability of these steady states is studied, so as to apply this model to the investigation of the branching of a filamentous lower plant.     

Coupled field analysis of heat flow in the near field of a microwave applicator for tumor ablation

Microwave tumor ablation (MTA) offers a new approach for the treatment of hepatic neoplastic disease. Reliable and accurate information regarding the heat distribution inside biological tissue subjected to microwave thermal ablation is important for the efficient design of microwave applicators and for optimizing experiments, which aim to assess the effects of therapeutic treatments. Currently there are a variety of computational methods based on different vascular structures in tissue, which aim to model heat distribution during ablation. This paper presents results obtained from two such computational models for temperature distributions produced by a clinical 2.45 GHz MTA applicator immersed in unperfused ex vivo bovine liver, and compares them with measured results from a corresponding ex vivo experiment. The computational methods used to model the temperature distribution in tissue caused by the insertion of a 5.6 mm diameter "wandlike" microwave applicator are the Green's function method and the finite element method (FEM), both of which provide solutions of the heat diffusion partial differential equation. The results obtained from the coupled field simulations are shown to be in good agreement with a simplified analysis based on the bio-heat equation and with ex vivo measurements of the heat distribution produced by the clinical MTA applicator.     

Dipole source localization by mottled sculpin. III. Orientation after site-specific, unilateral denervation of the lateral line system

To test the hypothesis that spatial excitation patterns along the lateral-line system underlie source localization, we videotaped the orientation behavior of blinded mottled sculpin in response to a small dipole source (50-Hz vibrating sphere) before and after unilateral denervation of the lateral line system on different body regions (head, trunk and head + trunk). Approach pathways were qualitatively similar to those followed by normal intact animals. Abnormal behavior (turning in circles) was not observed. However, the frequency with which fish placed their intact side facing the source increased by 12–89%, depending on the denervation site. The angular accuracy of orientation decreased by 20° to 60° (100% to 370% change) depending on source location and region of lateral line denervated. Deficits tended to be site-specific. For example, unilaterally denervating lateral-line organs on the head resulted in less accurate orienting responses when the source was located on the denervated side of the head, but not on the opposite side of the head or on either side of the trunk. Site-specific deficits and the absence of abnormal approach pathways argue that animals are relying on a point-by-point spatial representation of source location along the sensory surface rather than computations based on bilateral comparisons. Accepted: 28 May 1998     

Toral lateral line units of goldfish, Carassius auratus, are sensitive to the position and vibration direction of a vibrating sphere

We recorded the responses of lateral line units in the midbrain torus semicircularis of goldfish, Carassius auratus, to a 50-Hz vibrating sphere and determined the unit's spatial receptive fields for various distances between fish and sphere and for different directions of sphere vibration. All but one unit responded to the vibrating sphere with an increase in discharge rate. Only a proportion (25?%) of the units exhibited phase-locked responses. Receptive fields were narrow or broad and contained one, two or more areas of increased discharge rate. The data show that the receptive fields of toral lateral line units are in many respects similar to those of brainstem units but differ from those of afferent nerve fibres. The responses of primary afferents represent the pressure gradient pattern generated by a vibrating sphere and provide information about sphere location and vibration direction. Across the array of lateral line neuromasts, the fish brain in principle can derive this information. Nevertheless, toral units tuned to a distinct sphere location or sensitive to a distinct sphere vibration direction were not found. Therefore, it is conceivable that the torus semicircularis uses a population code to determine spatial location and vibration direction of a vibrating sphere.     

RAPD-PCR analysis for molecular characterization and genotoxic studies of a new marine fish cell line derived from Dicentrarchus labrax

Continuous cell lines could provide an important tool for studying epidemiology, toxicology, cellular physiology and the host–pathogen interactions. Random amplified polymorphic deoxyribonucleic acid analysis by PCR (RAPD-PCR) was used for the molecular characterization of Dicentrarchus labrax embryonic cells (DLEC) as a possible tool to detect DNA alterations in environmental genotoxic studies. We studied the DNA pattern of the DLEC fish cell line, a fibroblast-like cell line derived from European sea bass. From a total of 15 primers only six showed good discriminatory power for the amplification process on DNA samples collected from cells by three different methods (organic extraction, salting-out method and chelating agent extraction). The results obtained show that the cell line chosen for this study could be used as a possible tool for the detection of potential genotoxicity of numerous chemical compounds.     

Characterization of an RNA-directed DNA-polymerase from a cell line derived from a radiation-induced lymphoma in mice.

An RNA-directed DNA polymerase was purified from a cell line derived from a radiation-induced lymphoma in NIH Swiss mice which produced non-infectious type C virus particles. The enzyme was isolated from a high speed particulate fraction which bands at a density of 1.16--1.19 g/ml in a sucrose gradient, and purified by successive chromatography on DEAE-cellulose, phosphocellulose and hydroxyapatite. The purified DNA polymerase has a molecular weight of 68 000, a pH optimum of 7.5, a KCl optimum of 50 mM, and a Mn2+ optimum of 0.25 mM. It prefers (dT)15 . (A)n to (dT)15 . (dA)n as the primer template and transcribes the poly(C) strand of (dG)15 .(C)n and (dG)15 . (OMeC)n. It transcribes heteropolymeric regions of avian myeloblastosis virus 70 S RNA, and is inhibited by antiserum to Rauscher murine leukemia virus DNA polymerase. Comparison of the properties of DNA polymerase purified from radiation-induced lymphoma cells with the DNA polymerase purified from non-defective murine type C RNA tumor viruses shows that the mouse lymphoma enzyme is both biochemically and immunologically related to murine leukemia virus DNA polymerases.     

Establishment of a leukocyte cell line derived from peritoneal macrophages of fish,Labeo rohita (Hamilton, 1822)

A continuous leukocyte cell line with phagocytic activity was established from peritoneal macrophages of rohu, Labeo rohita (LRPM). LRPM was initiated from adherent mononuclear leukocytes isolated from peritoneal cavity of rohu, without use of any growth factors or feeder cells. These cells exhibited maximum growth at 30 °C in L-15 medium containing 20 % foetal bovine serum, and has been subcultured for more than 60 passages till date. The cells showed 85 % viability after 6 months of storage in liquid nitrogen. The species of origin of the LRPM was confirmed by the amplification and sequencing of 655 bp fragment of cytochrome oxidase subunit I of mitochondrial DNA. Functionally, LRPM showed phagocytic activity of yeast cells and fluorescent latex beads as evaluated by phase contrast and scanning electron microscopy, respectively. Immuno-modulators such as bacterial lipopolysaccharide and phorbol myristate acetate resulted in functional activation of LRPM; and enhanced their microbicidal activity through release of reactive oxygen species and nitric oxide. Culture supernatant from activated cells also revealed lysozyme activity. Cells of LRPM were positive for alpha-naphthyl acetate esterase enzyme indicating macrophage lineage. Our results indicate that this cell line can be a useful in vitro tool to study the role of macrophages in teleost immune system and to evaluate the effects of new aquaculture drugs. The LRPM cell line represents the first reported leukocyte cell line of peritoneal origin from any freshwater species of fish.     

Establishment and characterization of a human cell line, HS-MM, derived from a case of clear cell sarcoma

The characteristics of a new human clear cell sarcoma (CCSa) cell line, HS-MM, established from the pleural effusion in a 39-year-old man with lung metastasis, have been morphologically studied in vitro and in vivo. HS-MM cells growing on a cover-slip were round or spindle in shape with round nuclei containing extremely prominent nucleoli. Heterotransplantation of the cells into nude mice was easily succeeded following tumor development. Light microscopically, HS-MM cells, both in vitro and in vivo, were positive for anti-S-100 protein and anti-melanoma specific antibodies with immunostain, but no melanin pigment was detected in them. Ultrastructurally, the cells had round euchromatin-rich nuclei with large nucleoli revealing conspicuous nucleolonema, and contained a few mitochondria, rough endoplasmic reticulum and lysosomal dense bodies, besides a large amount of glycogen, but no melanosome in their cytoplasm. HS-MM cells retained and fully expressed morphologically unique characteristics as a CCSa, compatible with amelanotic type of malignant melanoma also. This cell line, HS-MM, therefore, proves to be extremely useful for clinicopathological studies on a CCSa.     

Responses of lateral line receptors to water flow in the Antarctic notothenioid, Trematomus bernacchii

The response properties of anterior lateral line afferent neurones in Trematomus bernacchii were recorded extracellularly while stimulating the fish with unidirectional water flows of varying velocity. Afferent neurone responses were either flow-sensitive or flow-insensitive. Flow-sensitive neurones showed linear increases in response magnitude with increasing flow rate and tonic non-adapting response properties. These findings indicate that flow-sensitive afferent neurones originate from lateral line receptors that detect absolute flow velocity. The likely explanation is that flow-sensitive afferent neurones innervate neuromasts located superficially on the skin and flow-insensitive neurones innervate neuromasts situated in sub-epidermal fluid-filled canals.     

Responses of midbrain lateral line units of the goldfish, Carassius auratus, to constant-amplitude and amplitude-modulated water wave stimuli

 Responses of mechanosensory lateral line units to constant-amplitude hydrodynamic stimuli and to sinusoidally amplitude-modulated water movements were recorded from the goldfish (Carassius auratus) torus semicircularis. Responses were classified by the number of spikes evoked in the unit's dynamic range and by the degree of phase locking to the carrier- and amplitude-modulation frequency of the stimulus. Most midbrain units showed phasic responses to constant-amplitude hydrodynamic stimuli. For different units peri-stimulus time histograms varied widely. Based on iso-displacement curves, midbrain units prefered either low frequencies (≤33 Hz), mid frequencies (50–100 Hz), or high frequencies (≥200 Hz). The distribution of the coefficient of synchronization to constant-amplitude stimuli showed that most units were only weakly phase locked. Midbrain units of the goldfish responded to amplitude-modulated water motions in a phasic/tonic or tonic fashion. Units highly phase locked to the amplitude modulation frequency, provided that modulation depth was at least 36%. Units tuned to one particular amplitude modulation frequency were not found. Accepted: 10 July 1999     

An experimental analysis of the flow field in a three-dimensional model of the human carotid artery bifurcation

Steady flow measurements were carried out in a rigid three-dimensional model of the human carotid artery bifurcation at a Reynolds number of 640 and a flow division ratio of 50/50. Both axial and secondary velocities were measured with a laser-Doppler anemometer. In the bulb opposite to the flow divider a zone with negative axial velocities was found with a maximal diameter of about 60% of the local diameter of the branch and a cross-sectional extent of about 25% of the local cross-sectional area. In the bulb the maximum axial velocity shifted towards the divider wall and at the end of the bulb an axial velocity plateau arose near the non-divider wall. Halfway through the bulb, secondary flow showed a vortex through which fluid flowed towards the divider wall near the bifurcation plane and back towards the non-divider wall near the upper walls.     

Growth characteristics of a cell line derived from the pig oviduct.

Further evidence for the establishment of the pig fallopian tube (PFT) cell line as a continuous cell line was shown by an increase in the maximum population density as the number of subcultures increased. The optimal pH and temperature-growth ranges appeared to be 7.4-7.8 and 37-41 degrees C respectively, and the population doubling time was 20-25 h under optimal growth conditions. With progressive subculture, the serum requirements dropped from 20 to 2%. A plating efficiency of 2 to 4% was found in all serial subcultures. Colonies were observed in agar suspension culture at the 146th subculture and thereafter. Chromosomal alterations were found in the 100th subculture and thereafter.     

Material flow analysis (MFA) of an eco-economic system: a case study of Wujin District, Changzhou, China

The economic and ecological aspects of a social system are coherently linked and can be examined by its material and energy flows. In this study, we used the material flow analysis (MFA) to model the material input and output of the Wujin District of Changzhou City, Jiangsu Province in China. It was revealed that: (1) total material input and material input per capita increased with economic development, while the total material output and material output per capita decreased consistently; (2) except for water, the total material input continued to increase. Input of solid materials grew faster than that of gaseous materials, while the total material output declined. The gas output accounted for the largest proportion of the output resulting in primary environmental pollution as burned fossil fuel; (3) water use in agriculture continued with an increasing trend while that in industrial and residential sectors decreased per capita. The total wastewater discharge and wastewater discharge per capita decreased with a faster decreasing rate of residential wastewater discharge followed by industrial wastewater discharge; (4) material input per unit GDP fluctuated and material output per unit GDP decreased. A decreasing trend in both water use and wastewater discharge per unit GDP was disclosed. These results suggest that the efficiency of resource use in the Wujin District has improved. This weakened the direct link between economic development and environmental deterioration. Additionally, we discussed the harmonic development between environment and economy. Potential limitations of MFA’s application were also discussed. It is suggested that effective measures should be taken for the enforcement of circular economic strategies and the construction of a resource-saving economy __________ Translated from Acta Ecologica Sinica, 2006, (8): 2578–2586 [译自:生态学报]     

Material flow analysis (MFA) of an eco-economic system:a case study of Wujin District,Changzhou,China

The economic and ecological aspects of a social system are coherently linked and can be examined by its material and energy flows.In this study,we used the material flow analysis (MFA) to model the material input and output of the Wujin District of Changzhou City,Jiangsu Province in China.It was revealed that:(1) total material input and material input per capita increased with economic development,while the total material out-put and material output per capita decreased consistently;(2) except for water,the total material input continued to increase.Input of solid materials grew faster than that of gaseous materials,while the total material output declined.The gas output accounted for the largest pro-portion of the output resulting in primary environmental pollution as burned fossil fuel; (3) water use in agriculture continued with an increasing trend while that in industrial and residential sectors decreased per capita.The total wastewater discharge and wastewater discharge per capita decreased with a faster decreasing rate of residential was-tewater discharge followed by industrial wastewater dis-charge; (4) material input per unit GDP fluctuated and material output per unit GDP decreased.A decreasing trend in both water use and wastewater discharge per unit GDP was disclosed.These results suggest that the effi-ciency of resource use in the Wujin District has improved.This weakened the direct link between economic develop-ment and environmental deterioration.Additionally,we discussed the harmonic development between environ-ment and economy.Potential limitations of MFA's application were also discussed.It is suggested that effec-tive measures should be taken for the enforcement of cir-cular economic strategies and the construction of a resource-saving economy     

Variations of glycogen: I. Following stimulation of Knollenorgan sensory cells,a lateral line electroreceptor of mormyrid fish

The metabolism of glycogen was studied in sensory cells of the mormyrid fish, Gnathonemus petersii. Knollenorgans, specific cutaneous electroreceptor organs of the lateral line system, have a spontancous electrical activity and their resting discharge in the absence of stimulation is about 0.04 kHz. Various types of stimulation can produce an increase in frequency; the highest frequency (1.30 kHz) is obtained by moving the Knollenorgan above water level. Glycogen was visualized in ultrathin sections after fixation in a solution of potassium ferricyanide and osmium tetroxide. The density of glycogen particles was determined morphometrically in sensory cells before stimulation, after high-frequency activity, and after reimmersion in water. An increase in the electrical activity of the Knollenorgan resulted in a decrease of the glycogen content of sensory cells. The glycogen store was replenished to about 85% of control within 40 min after stimulation and subsequent reimmersion. The results demonstrate that glycogen in the sensory cells of the Knollenorgan represents an energy source which can be catabolized during high electrical activity and replenished during rest.     

Variations of glycogen: II. Following deafferentation of Knollenorgan sensory cells,a lateral line electroreceptor of mormyrid fish

The effect of deafferentation on glycogen metabolism was studied in the sensory cells of mormyrid Knollenorgan electroreceptors. Glycogen was visualized in the sensory cells after fixation in a solution containing potassium ferricyanide and osmium tetroxide. The density variations of glycogen were evaluated by a morphometric method. Sectioning of the afferent nerve results in a cessation of the spontaneous receptor cells activity after 48 h and the glycogen content of these cells increases three fold in the first 5 days after nerve transection. From day 5 on, the glycogen concentration diminishes progressively until day 13. After the sensory cells had become completely deformed, the quantification of glycogen particles was no longer possible and the degeneration of the sensory cells was complete within 20 days after nerve section. These results show that (1) the afferent nerve fibre is indispensable for the anatomo-functional maintenance of the sensory cells and (2) the nerve has only an indirect influence on glycogen variations within the sensory cells.