Luminous Fish Research Articles

Inception of formation and early morphogenesis of the bacterial light organ of the sea urchin cardinalfish, Siphamia versicolor

The cardinalfish Siphamia versicolor (Perciformes: Apogonidae) forms a bioluminescent symbiosis with the marine luminous bacterium Photobacterium mandapamensis, harboring the bacteria in a ventral, disc-shaped light organ and using the bacterial light apparently for counterillumination and attracting prey. Little definitive information has been available on the developmental and microbiological events surrounding the initiation of symbiosis, a critical stage in the life history of the fish, in S. versicolor or any of the many other species of bacterially luminous fish. To identify the stage at which light organ formation begins, to determine the origin of cells forming the light organ, and to characterize its bacterial colonization status during development, early developmental stages of S. versicolor obtained and reared from wild-caught mouth-brooding males were examined with histological and microbiological methods. A light organ primordium was not evident in embryos, post-embryos, or pre-release larvae, whereas the light organ began to form within 1 day of release of full-term pre-flexion larvae from the mouths of male fish. Analysis of post-release larvae revealed that the light organ arises from a proliferation and differentiation of intestinal epithelial cells, and that it quickly develops structural complexity, including the formation of chambers and gaps contiguous with the intestinal epithelium. However, the nascent light organ remained uncolonized by the symbiotic bacteria through several days of post-release development, even in the presence of high numbers of the symbiotic bacteria. These results demonstrate that the inception of light organ formation in S. versicolor occurs independently of its symbiotic bacteria and that receptivity to bacterial colonization apparently requires substantial post-release development of the light organ. Larvae therefore most likely acquire their symbiotic bacteria from seawater, during or shortly after the transition from the pre-flexion to the flexion developmental stage.

Phylogeography of a flooded forest specialist fish from central Amazonia based on intron DNA: the cardinal tetra Paracheirodon axelrodi

Summary1. Historic and extant landscape structures and environmental conditions are known to influence phylogeographic patterns and population histories in organisms from Amazonia. Recent work suggests that events of the Tertiary Period have played a significant role in generating biodiversity in this exceptionally rich but understudied region. However, species distributions and population structures are also affected by recent environmental and physical changes, especially within highly dynamic ecosystems.2. The cardinal tetra is a small luminous fish native to the dynamic flooded forest ecosystems of the Rio Negro and Orinoco basins of South America. This very popular aquarium fish represents the single most important species in the ornamental fishery of the Rio Negro, an activity of high socio‐economic value for local riverine communities. Here we use a fine‐scale sampling regime and sequence data from the second intron of the Ribosomal protein S7 (S7 2) to investigate population structure, colonisation history and genealogical relationships in cardinal tetras of the Rio Negro.3. High levels of S7 2 polymorphisms revealed phylogeographic patterns across several temporal settings that appear associated with the complex dynamics of the region. Our results suggest a long history of isolation and persistence of cardinal tetra populations in the headwaters and upper regions of the Rio Negro and recent events of colonisation within the incipient Rio Negro floodplain. These colonisation events were followed by recent population expansions likely facilitated by the establishment of the extensive Rio Negro floodplain, an anabranching ecosystem of Holocene age.4. Our reconstruction of the phylogeographic history of cardinal tetras based on S7 2 intron sequence data reflects the complex influence of both geomorphological and climatic events through time in the Rio Negro basin. Our findings also indicate that in order to maintain the cardinal tetra fishery as a sustainable activity for rural Amazonians, the fishery should be restricted to the middle Rio Negro, the region of the basin where population replenishment is more likely to occur.

Genomic and phylogenetic characterization of luminous bacteria symbiotic with the deep-sea fish Chlorophthalmus albatrossis (Aulopiformes: Chlorophthalmidae).

Bacteria forming light-organ symbiosis with deep-sea chlorophthalmid fishes (Aulopiformes: Chlorophthalmidae) are considered to belong to the species Photobacterium phosphoreum. The identification of these bacteria as P. phosphoreum, however, was based exclusively on phenotypic traits, which may not discriminate between phenetically similar but evolutionarily distinct luminous bacteria. Therefore, to test the species identification of chlorophthalmid symbionts, we carried out a genomotypic (repetitive element palindromic PCR genomic profiling) and phylogenetic analysis on strains isolated from the perirectal light organ of Chlorophthalmus albatrossis. Sequence analysis of the 16S rRNA gene of 10 strains from 5 fish specimens placed these bacteria in a cluster related to but phylogenetically distinct from the type strain of P. phosphoreum, ATCC 11040(T), and the type strain of Photobacterium iliopiscarium, ATCC 51760(T). Analysis of gyrB resolved the C. albatrossis strains as a strongly supported clade distinct from P. phosphoreum and P. iliopiscarium. Genomic profiling of 109 strains from the 5 C. albatrossis specimens revealed a high level of similarity among strains but allowed identification of genomotypically different types from each fish. Representatives of each type were then analyzed phylogenetically, using sequence of the luxABFE genes. As with gyrB, analysis of luxABFE resolved the C. albatrossis strains as a robustly supported clade distinct from P. phosphoreum. Furthermore, other strains of luminous bacteria reported as P. phosphoreum, i.e., NCIMB 844, from the skin of Merluccius capensis (Merlucciidae), NZ-11D, from the light organ of Nezumia aequalis (Macrouridae), and pjapo.1.1, from the light organ of Physiculus japonicus (Moridae), grouped phylogenetically by gyrB and luxABFE with the C. albatrossis strains, not with ATCC 11040(T). These results demonstrate that luminous bacteria symbiotic with C. albatrossis, together with certain other strains of luminous bacteria, form a clade, designated the kishitanii clade, that is related to but evolutionarily distinct from P. phosphoreum. Members of the kishitanii clade may constitute the major or sole bioluminescent symbiont of several families of deep-sea luminous fishes.

Fish otoliths: do sizes correlate with taxonomic group, habitat and/or luminescence?

Otoliths are dense structures in the ears of fishes that function in hearing and gravity perception. Otolith (sagitta) diameters, as percentages of standard length (% SL), are calculated for 247 marine fish species in 147 families and compared by taxonomic group (usually order), habitat and presence or absence of luminescence. Otolith sizes range from 0.4-31.4 mm and 0.08-11.2% SL. The eel and spiny eel orders Anguilliformes and Notacanthiformes have small to very small otoliths, as do the triggerfish order Tetraodontiformes, pipefish order Gasterosteiformes, billfish suborder Scombroidei and many of the dragonfish order Stomiiformes. The soldierfish order Beryciformes has moderate to very large otoliths. The perch order Perciformes has a wide range of otolith sizes but most have small to moderate otoliths 2-5% SL. Only 16 out of the 247 species have the relatively largest otoliths, over 7% SL. Seven out of these 16 species are also luminous from a variety of habitats. Luminous species have slightly to much larger otoliths than non-luminous species in the same family Both beryciforms and luminous fishes live in low-light environments, where acute colour vision is probably impossible. Most fishes of the epipelagic surface waters have very small otoliths, perhaps due to background noise and/or excessive movement of heavy otoliths in rough seas. Bathypelagic species usually have small otoliths and regressed or absent swimbladders. Other habitats have species with a range of otolith sizes. While the relationship between hearing ability and otolith length is unknown, at least some groups with modified swim-bladders have larger otoliths, which may be associated with more acute hearing.

Evidence of luminous bacterial symbionts in the light organs of myctophid and stomiiform fishes

The myctophids and stomiiforms represent two common groups of luminous fishes, but the source of luminescence in these animals has remained undetermined. In this study, labeled luciferase gene fragments from luminous marine bacteria were used to probe DNA isolated from specific fish tissues. A positive signal was obtained from skin DNA in all luminous fishes examined, whereas muscle DNA gave a weaker signal and brain DNA was negative. This observation is consistent with luminous bacteria acting as the light source in myctophids and stomiiforms and argues against the genes necessary for luminescence residing on the fish chromosomes. To confirm the location of this signal, a bacterial probe was hybridized in situ to sections of a stomiiform. A strong signal was generated directly over specific regions of the fish light organs, whereas no signal was found over other internal or epidermal tissues of the fish. Taken together, these data provide the first indication that luminous bacterial symbionts exist in myctophids and stomiiforms and that these symbionts account for luminescence in these fishes.

Chemiluminometric techniques in clinical chemistry

Luminescent phenomena are widespread in nature and found in glow worms, luminous fish, and bacteria, when metabolic energy is partly converted to cold light, and in plants. Most of these phenomena can be explained by chemiluminescence. Chemiluminescence is characteristic for a variety of organic compounds oxidizable by H2O2. In those chemiluminescence reactions light is produced by oxidation of an aromatic compound (usually luminol or lucigenin) in the presence of H2O2 by a peroxidase. Bioluminescence, a subset of chemiluminescence, may be classified in four different forms: pyridine nucleotide linked in bacteria occurring with coupling of a redox and luciferase reaction; adenine nucleotide linked in fireflies in which oxygen, ATP and luciferin react under the influence of luciferase; furthermore enzyme substrate linked and photoprotein linked bioluminometric processes are observed in arthropods and in jelly fish.

Detection of coelenterazine and related luciferase activity in the tissues of the luminous fish, Vinciguerria attenuata

1. 1. We attempted to identify the components of the light-emitting system of the bioluminescent fish, Vinciguerria attenuata (Photichthyidae). 2. 2. Methanol extracts of the digestive tract and body tissues were analysed by HPLC. Assays for the detection of coelenterazine or Vargula luciferin were performed on the collected fractions. 3. 3. The corresponcling luciferase activities were also assayed in the solid residues. 4. 4. No cross-reactions with Vargula luciferase and luciferin were detected. 5. 5. Coelenterazine was detected in the tissues of the fish. The eoelenterazine content of the digestive tract represented as much as 95% of the total coelenterazine content of the fish. Luciferase activity, specific for eoelenterazine, was absent from the digestive tract, but present in the rest of the body. 6. 6. These results suggest that the luminescent system in Vinciguerria photophores is of the coelenterate type. Coelenterazine distribution in the tissues of the fish suggests that it might be obtained from the diet.

Adrenergic control of luminescence and cellular metabolism in Porichthys isolated luminous organs

1. Isolated photophores from the luminous fish Porichthys produce light in response to adrenaline and the metabolic inhibitors iodoacetic acid (IAA) or potassium cyanide (KCN). 2. We attempted to analyse the interactions of cellular metabolism and adrenergic stimulation of the photogenic cells. 3. Photophores were treated with IAA in the presence of pyruvate. In these conditions, IAA does inhibit glycolysis without inducing any luminescent activity of the cells. 4. Similarly, other photophores were incubated with KCN in the presence of glucose, in order to inhibit cellular respiration while keeping the luminous system inactive. 5. We observed that adrenergic stimulation of these photophores remained effective and induced a light emission, demonstrating that glycolytic and oxidative metabolism are not absolutely essential to the mechanism underlying adrenergic activation of the luminous system. 6. The comparison of these luminescences with adrenergic responses of control photophores showed that the light emission to adrenaline was markedly inhibited by glycolysis blockade but potentiated by an inhibition of cellular respiration. 7. As the inhibitory effect of IAA does not result from a direct action of IAA on the luminous system, these results suggest that adrenaline activation of adrenergic receptors might interact with glycolysis in photogenic cells. 8. Glyceraldehyde 3-phosphate, or some derivatives, could be implicated in the glycolytic control of luminescence in the photophores.

A novel red fluorescent protein from the deep sea luminous fish Malacosteus niger

1. 1. A protein, blue in daylight and red fluorescent under ultraviolet (366 nm) light, has been extracted and partially purified from the red-emitting suborbital luminous organ of the deep sea fish Malacosteus niger. 2. 2. The protein had a molecular weight on G-100 Sephadex of approx. 32,000 and on SDS polyacrylamide gel electrophoresis of approx. 30,000. 3. 3. The absorbance maxima of the isolated protein were at 555 nm and 612 nm. 4. 4. There were four fluorescence excitation maxima (305, 332, 374 and 392 nm) corresponding to two emission maxima (564 and 626 nm; 564 nm for 305 nm and 374 nm and 626 nm for 332 nm and 392 nm). 5. 5. The protein exhibited a low intensity phosphorescence after exposure to visible light. 6. 6. The chromophore appeared to be covalently bound, some being extracted in acid methanol at 0°C or in boiling methanol. 7. 7. The protein has characteristics similar to a phycobiliprotein, previously found only in blue-green and red algae. 8. 8. Similar, but not identical, proteins were also isolated from two other related stomiatoid fishes, Aristostomias and Pachystomias.

Relationship between luminous fish and symbiosis. II. Chemical composition of lipopolysaccharides isolated from symbiotic luminous bacteria in the luminous marine fish, Physiculus japonicus.

Relationship between luminous fish and symbiosis. II. Chemical composition of lipopolysaccharides isolated from symbiotic luminous bacteria in the luminous marine fish, Physiculus japonicus.

Contribution by symbiotically luminous fishes to the occurrence and bioluminescence of luminous bacteria in seawater

Seawater samples from a variety of locations contained viable luminous bacteria, but luminescence was not detectable although the system used to measure light was sensitive enough to measure light from a single, fully induced luminous bacterial cell. When the symbiotically luminous fishCleidopus gloriamaris was placed in a sterile aquarium, plate counts of water samples showed an increase in luminous colony-forming units. Luminescence also increased, decreasing when the fish was removed. Light measurements of water samples from a sterile aquarium containingPhotoblepharon palpebratus, another symbiotically luminous fish, whose bacterial symbionts have not been cultured, showed a similar pattern of increasing light which rapidly decreased upon removal of the fish. These experiments suggest that symbiotically luminous fishes release brightly luminous bacteria from light organs into their environment and may be a source of planktonic luminous bacteria. Although planktonic luminous bacteria are generally not bright when found in seawater, water samples from environments with populations of symbiotically luminous fish may show detectable levels of light.

Relationship between luminous fish and symbiosis. I. Comparative studies of lipopolysaccharides isolated from symbiotic luminous bacteria of the luminous marine fish, Physiculus japonicus.

In order to investigate the relationship between host and symbiosis in the luminous marine fish, Physiculus japonicus, the bacterial lipopolysaccharides (LPS) of symbiotic luminous bacteria were compared serologically and electrophoretically. Five symbiotic luminous bacteria (PJ strains) were separately isolated from five individuals of this fish species caught at three points, off the coasts of Chiba, Nakaminato, and Oharai. LPS preparations were made from these bacteria by Westphal's phenol-water method and highly purified by repeated ultracentrifugation. These LPSs contained little or no 2-keto-3-deoxyoctonate and had powerful mitogenic activity. In sodium dodecylsulfate polyacrylamide gel electrophoresis, these PJ-1 to -5 LPSs were separated by their electrophoretic patterns into three groups; the first group included PJ-1 and PJ-4, the second group PJ-2 and PJ-3, and the third group PJ-5 alone. The results agreed with those of the double immunodiffusion test; precipitin lines completely coalesced within each group but not with other groups. In immunoelectrophoresis, one precipitin line was observed between anti PJ-2 LPS serum and PJ-5 LPS but the electrophoretic mobility of PJ-5 LPS was clearly different from that of the PJ-2 LPS group. Furthermore, in a 50% inhibition test with PJ-2 LPS by the passive hemolysis system, the doses of PJ-2 LPS, PJ-3 LPS, and PJ-5 LPS required for 50% inhibition (ID50) in this system were 0.25, 0.25, and 21.6 micrograms/ml for each alkali-treated LPS, respectively, and the ID50's of both PJ-1 LPS and PJ-4 LPS were above 1,000 micrograms/ml. These results indicate that PJ-5 LPS has an antigenic determinant partially in common with LPS from the PJ-2 group but not with LPS from the PJ-1 group and that the symbiotic luminous bacterium PJ-5 is more closely related to the PJ-2 group than to the PJ-1 group. These results show that the species Physiculus japonicus is symbiotically associated with at least three immunologically different strains of luminous marine bacteria in its specialized light organ.

New recodrs of luminous fishes in north Norwegian waters

Abstract The first records of Cyclothone alba, Lampanyctus macdonaldi, and Protomyctophum arcticum from Norwegian waters are reviewed together with some records of the rare Argyropelecus hemigymnus, Argyropelecus olfersi, and Notolepis rissoi. The specimens originate partly from stomach contents of Atlantic salmon, Salmo salar, long-line caught in 1969–72, and partly from pelagic trawl hauls in 1980, off Vesteralen, N. Norway. Environmental conditions of the Norwegian slope mesopelagial are briefly discussed, and it is pointed out that diversity of smaller luminous fishes here may be larger than previously assumed. The presence of ripe Argyropelecus females is suggested to indicate existing spawning populations in these waters.

Probing Deeper, Higher, Farther

Probing Deeper, Higher, Farther

Bioluminescence

In the early days of marine biology, a century ago, when many new species were being discovered, scientists were puzzled by strange organs that some of these animals possessed. Various functions were ascribed to them, such as pressurereceptors, infra-red detectors and accessory eyes. It is now known that many of these puzzling organs are photophores or light-organs. Deep-sea animals possess the same sensory modalities as surface and shallowwater species—smell, sight, hearing, vibrational sense, touch. Sensory organs may be accentuated or specialized in certain ways to make them more efficient in the peculiar conditions obtaining in deep waters. Signals which animals emit are sounds, low-frequency vibrations, odours and light. In an environment where perceptible daylight is wanting, light is produced by the animals themselves. Very many deep-sea animals have well-developed eyes: to function these eyes need light, and the light is provided by luminescence. It is now apparent that luminescence is a wide-spread and common phenomenon in the deep sea. The abundance, complexity and wide distribution of light-organs among bathypelagic animals attest to this. In an intensive investigation of a small area near Bermuda, Beebe (1937) found that two-thirds of the species of deep-sea fish captured below 700 m were luminous; reckoned as individuals, over ninetenths were luminous. This high proportion of luminous fish was due to the numerical abundance of cyclothonids and myctophids in the catches.

All about Fish and other Denizens of the Seas and Rivers

MR. BERRIDGE fills his pages with a large amount of interesting information concerning marine animals. There are chapters on fish in general, fish that make nests, the food of fish, luminous fish, electric fish, goldfish, and many other animals including invertebrates such as oysters and cockles, lobsters and shrimps, corals and sponges. The book is amusing and the original photographs are good, sometimes very good, but it is a pity that they do not match the text, for when reading about a basking-shark or a sea-serpent we find pictures of goldfish, and a remora illustrates the remarks on oysters.