WorldWideScience

Sample records for chromatophores

  1. Sensitive-cell-based fish chromatophore biosensor

    Science.gov (United States)

    Plant, Thomas K.; Chaplen, Frank W.; Jovanovic, Goran; Kolodziej, Wojtek; Trempy, Janine E.; Willard, Corwin; Liburdy, James A.; Pence, Deborah V.; Paul, Brian K.

    2004-07-01

    A sensitive biosensor (cytosensor) has been developed based on color changes in the toxin-sensitive colored living cells of fish. These chromatophores are highly sensitive to the presence of many known and unknown toxins produced by microbial pathogens and undergo visible color changes in a dose-dependent manner. The chromatophores are immobilized and maintained in a viable state while potential pathogens multiply and fish cell-microbe interactions are monitored. Low power LED lighting is used to illuminate the chromatophores which are magnified using standard optical lenses and imaged onto a CCD array. Reaction to toxins is detected by observing changes is the total area of color in the cells. These fish chromatophores are quite sensitive to cholera toxin, Staphococcus alpha toxin, and Bordatella pertussis toxin. Numerous other toxic chemical and biological agents besides bacterial toxins also cause readily detectable color effects in chromatophores. The ability of the chromatophore cell-based biosensor to distinguish between different bacterial pathogens was examined. Toxin producing strains of Salmonella enteritis, Vibrio parahaemolyticus, and Bacillus cereus induced movement of pigmented organelles in the chromatophore cells and this movement was measured by changes in the optical density over time. Each bacterial pathogen elicited this measurable response in a distinctive and signature fashion. These results suggest a chromatophore cell-based biosensor assay may be applicable for the detection and identification of virulence activities associated with certain air-, food-, and water-borne bacterial pathogens.

  2. Cephalopod chromatophores: neurobiology and natural history.

    Science.gov (United States)

    Messenger, J B

    2001-11-01

    The chromatophores of cephalopods differ fundamentally from those of other animals: they are neuromuscular organs rather than cells and are not controlled hormonally. They constitute a unique motor system that operates upon the environment without applying any force to it. Each chromatophore organ comprises an elastic sacculus containing pigment, to which is attached a set of obliquely striated radial muscles, each with its nerves and glia. When excited the muscles contract, expanding the chromatophore; when they relax, energy stored in the elastic sacculus retracts it. The physiology and pharmacology of the chromatophore nerves and muscles of loliginid squids are discussed in detail. Attention is drawn to the multiple innervation of dorsal mantle chromatophores, of crucial importance in pattern generation. The size and density of the chromatophores varies according to habit and lifestyle. Differently coloured chromatophores are distributed precisely with respect to each other, and to reflecting structures beneath them. Some of the rules for establishing this exact arrangement have been elucidated by ontogenetic studies. The chromatophores are not innervated uniformly: specific nerve fibres innervate groups of chromatophores within the fixed, morphological array, producing 'physiological units' expressed as visible 'chromatomotor fields'. The chromatophores are controlled by a set of lobes in the brain organized hierarchically. At the highest level, the optic lobes, acting largely on visual information, select specific motor programmes (i.e. body patterns); at the lowest level, motoneurons in the chromatophore lobes execute the programmes, their activity or inactivity producing the patterning seen in the skin. In Octopus vulgaris there are over half a million neurons in the chromatophore lobes, and receptors for all the classical neurotransmitters are present, different transmitters being used to activate (or inhibit) the different colour classes of chromatophore

  3. Chromatophore motor fields in the squid, Lolliguncula brevis

    OpenAIRE

    Graham, P. F.; Frank, M M; Pinsker, H. M.

    1988-01-01

    Chromatophore motoneurones in Lolliguncula brevis are known to originate in the suboesophageal lobes of the brain and to project directly to the mantle and fin through bilateral stellate ganglia and fin nerves. The chromatophore motor fields of stellar and fin nerves were investigated by stimulation of the cut end of individual nerves in a semi-intact preparation. This elicited expansion of yellow and brown chromatophores in distinct motor fields. Brown chromatophores extended over the entire...

  4. Colour gamuts in polychromatic dielectric elastomer artificial chromatophores

    Science.gov (United States)

    Rossiter, Jonathan; Conn, Andrew; Cerruto, Antonio; Winters, Amy; Roke, Calum

    2014-03-01

    Chromatophores are the colour changing organelles in the skins of animals including fish and cephalopods. The ability of cephalopods in particular to rapidly change their colouration in response to environmental changes, for example to camouflage against a new background, and in social situations, for example to attract a mate or repel a rival, is extremely attractive for engineering, medical, active clothing and biomimetic robotic applications. The rapid response of these chromatophores is possible by the direct coupling of fast acting muscle and pigmented saccules. In artificial chromatophores we are able to mimic this structure using electroactive polymer artificial muscles. In contrast to prior research which has demonstrated monochromatic artificial chromatophores, here we consider a novel multi-colour, multi-layer, artificial chromatophore structure inspired by the complex dermal chromatophore unit in nature and which exploits dielectric elastomer artificial muscles as the electroactive actuation mechanism. We investigate the optical properties of this chromatophore unit and explore the range of colours and effects that a single unit and a matrix of chromatophores can produce. The colour gamut of the multi-colour chromatophore is analysed and shows its suitability for practical display and camouflage applications. It is demonstrated how, by varying actuator strain and chromatophore base colour, the gamut can be shifted through colour space, thereby tuning the artificial chromatophore to a specific environment or application.

  5. Neural Regulation Of Chromatophore Function In Cephalopods

    Science.gov (United States)

    2015-05-19

    communication . 15.  SUBJECT TERMS CHROMATOPHORE, CEPHALOPODS 16.  SECURITY CLASSIFICATION OF: 17.  LIMITATION OF       ABSTRACT UU 18.  NUMBER        OF...static and dynamic patterns used for a variety of purposes, including camouflage and inter- and intra-specific communication . The patterns made by...Symposium on Advances in Invertebrate Neurobiology, Polish Neuroscience Society, Poznan, Poland Symposium on Cephalopod Regeneration, Stazione Zoologica

  6. The architecture of Rhodobacter sphaeroides chromatophores.

    Science.gov (United States)

    Scheuring, Simon; Nevo, Reinat; Liu, Lu-Ning; Mangenot, Stéphanie; Charuvi, Dana; Boudier, Thomas; Prima, Valerie; Hubert, Pierre; Sturgis, James N; Reich, Ziv

    2014-08-01

    The chromatophores of Rhodobacter (Rb.) sphaeroides represent a minimal bio-energetic system, which efficiently converts light energy into usable chemical energy. Despite extensive studies, several issues pertaining to the morphology and molecular architecture of this elemental energy conversion system remain controversial or unknown. To tackle these issues, we combined electron microscope tomography, immuno-electron microscopy and atomic force microscopy. We found that the intracellular Rb. sphaeroides chromatophores form a continuous reticulum rather than existing as discrete vesicles. We also found that the cytochrome bc1 complex localizes to fragile chromatophore regions, which most likely constitute the tubular structures that interconnect the vesicles in the reticulum. In contrast, the peripheral light-harvesting complex 2 (LH2) is preferentially hexagonally packed within the convex vesicular regions of the membrane network. Based on these observations, we propose that the bc1 complexes are in the inter-vesicular regions and surrounded by reaction center (RC) core complexes, which in turn are bounded by arrays of peripheral antenna complexes. This arrangement affords rapid cycling of electrons between the core and bc1 complexes while maintaining efficient excitation energy transfer from LH2 domains to the RCs.

  7. Macroscale and Microscale Structural Characterization of Cephalopod Chromatophores

    Science.gov (United States)

    2011-04-01

    stretchable skin (Mathger and Hanlon, 2007; Cloney and Florey, 1968) (Figure 1b). Beneath the transparent epidermis layer is a layer of thousands of...muscles (Cloney and Florey, 1968). The chromatophore organs alter their appearance through control of the visual presented area of Epidermis ...quickly bonded to the skin. By gluing the o-ring to the dermis while it was still attached to the mantle, the natural tension and dimensions of the in

  8. Eye-independent, light-activated chromatophore expansion (LACE) and expression of phototransduction genes in the skin of Octopus bimaculoides

    OpenAIRE

    Ramirez, M. Desmond; Todd H Oakley

    2015-01-01

    Cephalopods are renowned for changing the color and pattern of their skin for both camouflage and communication. Yet, we do not fully understand how cephalopods control the pigmented chromatophore organs in their skin and change their body pattern. Although these changes primarily rely on eyesight, we found that light causes chromatophores to expand in excised pieces of Octopus bimaculoides skin. We call this behavior light-activated chromatophore expansion (or LACE). To uncover how octopus s...

  9. Chromatophoromas and chromatophore hyperplasia in Pacific rockfish (Sebastes spp.).

    Science.gov (United States)

    Okihiro, M S; Whipple, J A; Groff, J M; Hinton, D E

    1993-04-15

    Pacific rockfish from Cordell Bank, off central California (United States), were collected and histologically examined from 1985 to 1990. Hyperplastic and neoplastic cutaneous lesions, involving dermal chromatophores, were observed in five species; yellowtail rockfish (Sebastes flavidus), bocaccio (S. paucispinis), olive rockfish (S. serranoides), widow rockfish (S. entomelas), and chilipepper rockfish (S. goodei). Yearly prevalences were highest in S. paucispinis (29-38%). Prevalence was initially low in S. flavidus, but increased more than 3-fold from 1985 (7.5%) to 1990 (25%). The majority of lesions were black, but white, yellow, orange, red, and mixed-color variants were also seen. Lesions were found in skin, fins, lips, gingiva, tongue, urogenital papilla, conjunctiva, and cornea of the eye. Flat lesions were consistent with melanophore (black), xanthophore (yellow or orange), and erythrophore (red) hyperplasia. Neoplastic lesions included melanophoromas, amelanotic melanophoromas, xanthophoromas, erythrophoromas, and mixed chromatophoromas. Although etiology has not been determined, interest is currently focused on potential exposure to chemical and radioactive carcinogens from the Farallon Island Radioactive Waste Dump, 30 km to the south.

  10. Chromatophore distribution and inferior performance of albino Japanese flounder Paralichthys olivaceus with special reference to different chromatophore expression between albinism and pseudo-albinism.

    Science.gov (United States)

    Shikano, Takahito; Shimada, Yukinori; Nakamura, Aiko

    2007-05-01

    Albinism with a large variation in body color was found in a hatchery population of Japanese flounder. In addition to albinism, ambicoloration and pseudo-albinism were simultaneously observed in some individuals. Albinos had a remarkably lower number of melanophores on the scales of ocular side than wild-type individuals did, although no significant difference was observed in the numbers of xanthophores and iridophores. The intensity of body color significantly correlated with the number of melanophores among the albinos. No significant differences were observed in the intensity of body color and the number of melanophores between the ocular side and the ambicoloration area. Pseudo-albinism was accompanied by the reductions of melanophores and xanthophores, indicating the different expression patterns of chromatophores between albinism and pseudo-albinism. The combined effects of albinism and pseudo-albinism caused the disappearances of melanophores and xanthophores in the pseudo-albinism area of albinos. In addition to chromatophores, the different characteristics of several phenotypic traits were observed between albinos and wild-type individuals. Growth-related traits of the albinos were inferior to those of the wild-type individuals. Furthermore, the albinos had a larger pseudo-albinism area and a higher vertebral deformed rate than the wild-type individuals did. Individual multilocus heterozygosity and inbreeding coefficient measured by microsatellite loci did not show any indication that the albinos had higher inbreeding coefficient than the wild-type individuals did. This study demonstrated the expression patterns of chromatophores in the body color abnormalities of a flatfish species and the potential pleiotropic effects of an albinism gene on some phenotypic traits.

  11. Ultrastructural and biochemical analysis of epidermal xanthophores and dermal chromatophores of the teleost Sparus aurata.

    Science.gov (United States)

    Ferrer, C; Solano, F; Zuasti, A

    1999-04-01

    We have studied the pigmentary system of the teleost Sparus aurata skin by electron microscopy and chromatographic analysis. Under electron microscopy, we found the dermis to contain the three major types of recognized chromatophores: melanophores, xanthophores and iridophores. Melanophores were more abundant in the dorsal region, whereas the iridophores were more abundant in the ventral region. The most important discovery was that of epidermal xanthophores. Epidermal xanthophores were the only chromatophores in the epidermis, something only found in S aurata and in a teleost species living in the Antartic sea. In contrast, the biochemical analysis did not establish any special characteristics: we found pteridine and flavin pigments located mostly in the pigmented dorsal region. Riboflavin and pterin were two of the most abundant coloured pigment types, but other colourless pigments such as xanthopterin and isoxanthopterin were also detected.

  12. Ultrastructural and biochemical analysis of epidermal xanthophores and dermal chromatophores of the teleost Sparus aurata

    OpenAIRE

    Ferrer, C.; Solano, F.; Zuasti, A

    1999-01-01

    We have studied the pigmentary system of the teleost Sparus aurata skin by electron microscopy and chromatographic analysis. Under electron microscopy, we found the dermis to contain the three major types of recognized chromatophores: melanophores, xanthophores and iridophores. Melanophores were more abundant in the dorsal region, whereas the iridophores were more abundant in the ventral region. The most important discovery was that of epidermal xanthophore...

  13. [Activation and inhibition of photoinduced proton absorption in Rhodospirillum rubrum chromatophores by detergents and solvents].

    Science.gov (United States)

    Shaposhnikova, M G; Pakshina, E V; Shubin, V V; Krasnovskiĭ, A A

    1979-01-01

    The effects of detergents (Triton X-100) and solvents (diethyl ether, metanol) on the reversible light-induced proton uptake, photophosphorylation and band shift of the carotenoid in chromatophores from R. rubrum are described. All these compounds were found to stimulate the extent of light-induced proton uptake with subsequent inhibition when the concentrations were increased. Stimulation of proton uptake is accompanied by inhibition of both phosphorylation and carotenoid absorbance shift.

  14. Immobilization of fish chromatophores for use as a micro-biosensor for biological toxins

    Directory of Open Access Journals (Sweden)

    Mojović Ljiljana V.

    2003-01-01

    Full Text Available Chromatophores isolated from the Siamese fighting fish, Betta splendens represent a class of living cells that provide a vivid color response to microbial pathogens and environmental toxins. The selection of the most appropriate microcarrier and the development of the optimal technique for the chromatophore immobilization in order to enable directed transport of the sensor cells throughout microchannels of the biosensor, as well to preserve the cell survival and its functionality was studied. Microcarriers derived from glass, polystyrene and gelatin (collagen were tested as substrates for chromatophore attachement. Gelatin microcarriers were found to be the most suitable, due to high attachment efficiency (95% of attached cells, preservation of the cell viability and enhanced cell sensitivity. The optimum conditions for fish cell immobilization on collagen microcarriers were determined based on the cell-to-microcarrier bead ratio and the pH of the solution. The rate of cell attachment to the gelatin microcarrier followed first-order kinetics. Pretreatment of the gelatin beads with fibronectin, known as a cell attachment-promoting agent, resulted in a 10% higher attachment rate constant (k.

  15. SpotMetrics: An Open-Source Image-Analysis Software Plugin for Automatic Chromatophore Detection and Measurement

    Science.gov (United States)

    Hadjisolomou, Stavros P.; El-Haddad, George

    2017-01-01

    Coleoid cephalopods (squid, octopus, and sepia) are renowned for their elaborate body patterning capabilities, which are employed for camouflage or communication. The specific chromatic appearance of a cephalopod, at any given moment, is a direct result of the combined action of their intradermal pigmented chromatophore organs and reflecting cells. Therefore, a lot can be learned about the cephalopod coloration system by video recording and analyzing the activation of individual chromatophores in time. The fact that adult cephalopods have small chromatophores, up to several hundred thousand in number, makes measurement and analysis over several seconds a difficult task. However, current advancements in videography enable high-resolution and high framerate recording, which can be used to record chromatophore activity in more detail and accuracy in both space and time domains. In turn, the additional pixel information and extra frames per video from such recordings result in large video files of several gigabytes, even when the recording spans only few minutes. We created a software plugin, “SpotMetrics,” that can automatically analyze high resolution, high framerate video of chromatophore organ activation in time. This image analysis software can track hundreds of individual chromatophores over several hundred frames to provide measurements of size and color. This software may also be used to measure differences in chromatophore activation during different behaviors which will contribute to our understanding of the cephalopod sensorimotor integration system. In addition, this software can potentially be utilized to detect numbers of round objects and size changes in time, such as eye pupil size or number of bacteria in a sample. Thus, we are making this software plugin freely available as open-source because we believe it will be of benefit to other colleagues both in the cephalopod biology field and also within other disciplines. PMID:28298896

  16. SpotMetrics: An Open-Source Image-Analysis Software Plugin for Automatic Chromatophore Detection and Measurement.

    Science.gov (United States)

    Hadjisolomou, Stavros P; El-Haddad, George

    2017-01-01

    Coleoid cephalopods (squid, octopus, and sepia) are renowned for their elaborate body patterning capabilities, which are employed for camouflage or communication. The specific chromatic appearance of a cephalopod, at any given moment, is a direct result of the combined action of their intradermal pigmented chromatophore organs and reflecting cells. Therefore, a lot can be learned about the cephalopod coloration system by video recording and analyzing the activation of individual chromatophores in time. The fact that adult cephalopods have small chromatophores, up to several hundred thousand in number, makes measurement and analysis over several seconds a difficult task. However, current advancements in videography enable high-resolution and high framerate recording, which can be used to record chromatophore activity in more detail and accuracy in both space and time domains. In turn, the additional pixel information and extra frames per video from such recordings result in large video files of several gigabytes, even when the recording spans only few minutes. We created a software plugin, "SpotMetrics," that can automatically analyze high resolution, high framerate video of chromatophore organ activation in time. This image analysis software can track hundreds of individual chromatophores over several hundred frames to provide measurements of size and color. This software may also be used to measure differences in chromatophore activation during different behaviors which will contribute to our understanding of the cephalopod sensorimotor integration system. In addition, this software can potentially be utilized to detect numbers of round objects and size changes in time, such as eye pupil size or number of bacteria in a sample. Thus, we are making this software plugin freely available as open-source because we believe it will be of benefit to other colleagues both in the cephalopod biology field and also within other disciplines.

  17. Synchronous changes in coral chromatophore tissue density and skeletal banding as an adaptive response to environmental change

    Science.gov (United States)

    Ardisana, R. N.; Miller, C. A.; Sivaguru, M.; Fouke, B. W.

    2013-12-01

    Corals are a key reservoir of biodiversity in coastal, shallow water tropical marine environments, and density banding in their aragonite skeletons is used as a sensitive record of paleoclimate. Therefore, the cellular response of corals to environmental change and its expression in skeletal structure is of significant importance. Chromatophores, pigment-bearing cells within the ectoderm of hermatypic corals, serve to both enhance the photosynthetic activity of zooxanthellae symbionts, as well as protect the coral animal from harmful UV radiation. Yet connections have not previously been drawn between chromatophore tissue density and the development of skeletal density bands. A histological analysis of the coral Montastrea faveolata has therefore been conducted across a bathymetric gradient of 1-20 m on the southern Caribbean island of Curaçao. A combination of field and laboratory photography, serial block face imaging (SBFI), two-photon laser scanning microscopy (TPLSM), and 3D image analysis has been applied to test whether M. faveolata adapts to increasing water depth and decreasing photosynthetically active radiation by shifting toward a more heterotrophic lifestyle (decreasing zooxanthellae tissue density, increasing mucocyte tissue density, and decreasing chromatophores density). This study is among the first to collect and evaluate histological data in the spatial context of an entire unprocessed coral polyp. TPLSM was used to optically thin section unprocessed tissue biopsies with quantitative image analysis to yield a nanometer-scale three-dimensional map of the quantity and distribution of the symbionts (zooxanthellae) and a host fluorescent pigments (chromatophores), which is thought to have photoprotective properties, within the context of an entire coral polyp. Preliminary results have offered new insight regarding the three-dimensional distribution and abundance of chromatophores and have identified: (1) M. faveolata tissue collected from 8M SWD do

  18. Possible involvement of cone opsins in distinct photoresponses of intrinsically photosensitive dermal chromatophores in tilapia Oreochromis niloticus.

    Directory of Open Access Journals (Sweden)

    Shyh-Chi Chen

    Full Text Available Dermal specialized pigment cells (chromatophores are thought to be one type of extraretinal photoreceptors responsible for a wide variety of sensory tasks, including adjusting body coloration. Unlike the well-studied image-forming function in retinal photoreceptors, direct evidence characterizing the mechanism of chromatophore photoresponses is less understood, particularly at the molecular and cellular levels. In the present study, cone opsin expression was detected in tilapia caudal fin where photosensitive chromatophores exist. Single-cell RT-PCR revealed co-existence of different cone opsins within melanophores and erythrophores. By stimulating cells with six wavelengths ranging from 380 to 580 nm, we found melanophores and erythrophores showed distinct photoresponses. After exposed to light, regardless of wavelength presentation, melanophores dispersed and maintained cell shape in an expansion stage by shuttling pigment granules. Conversely, erythrophores aggregated or dispersed pigment granules when exposed to short- or middle/long-wavelength light, respectively. These results suggest that diverse molecular mechanisms and light-detecting strategies may be employed by different types of tilapia chromatophores, which are instrumental in pigment pattern formation.

  19. Studies on bacterial chromatophores II. Energy transfer and photooxidative bleaching of bacteriochlorophyll in relation to structure in normal and carotenoid-depleted Chromatium

    NARCIS (Netherlands)

    Bril, C.

    1963-01-01

    Electronic energy transfer, fluorescence emission spectra and photooxidative bleaching of bacteriochlorophyll in Chromatium chromatophores were shown to be affected by detergent action and by inhibition of normal carotenoid synthesis in the parent cells. These phenomena are discussed in relation to

  20. The ancestor of the Paulinella chromatophore obtained a carboxysomal operon by horizontal gene transfer from a Nitrococcus-like γ-proteobacterium

    Directory of Open Access Journals (Sweden)

    Glöckner Gernot

    2007-06-01

    Full Text Available Abstract Background Paulinella chromatophora is a freshwater filose amoeba with photosynthetic endosymbionts (chromatophores of cyanobacterial origin that are closely related to free-living Prochlorococcus and Synechococcus species (PS-clade. Members of the PS-clade of cyanobacteria contain a proteobacterial form 1A RubisCO (ribulose-1,5-bisphosphate carboxylase/oxygenase that was acquired by horizontal gene transfer (HGT of a carboxysomal operon. In rDNA-phylogenies, the Paulinella chromatophore diverged basal to the PS-clade, raising the question whether the HGT occurred before or after the split of the chromatophore ancestor. Results Phylogenetic analyses of the almost complete rDNA operon with an improved taxon sampling containing most known cyanobacterial lineages recovered the Paulinella chromatophore as sister to the complete PS-clade. The sequence of the complete carboxysomal operon of Paulinella was determined. Analysis of RubisCO large subunit (rbcL sequences revealed that Paulinella shares the proteobacterial form 1A RubisCO with the PS-clade. The γ-proteobacterium Nitrococcus mobilis was identified as sister of the Paulinella chromatophore and the PS-clade in the RubisCO phylogeny. Gene content and order in the carboxysomal operon correlates well with the RubisCO phylogeny demonstrating that the complete carboxysomal operon was acquired by the common ancestor of the Paulinella chromatophore and the PS-clade through HGT. The carboxysomal operon shows a significantly elevated AT content in Paulinella, which in the rbcL gene is confined to third codon positions. Combined phylogenies using rbcL and the rDNA-operon resulted in a nearly fully resolved tree of the PS-clade. Conclusion The HGT of the carboxysomal operon predated the divergence of the chromatophore ancestor from the PS-clade. Following HGT and divergence of the chromatophore ancestor, diversification of the PS-clade into at least three subclades occurred. The

  1. Eye-independent, light-activated chromatophore expansion (LACE) and expression of phototransduction genes in the skin of Octopus bimaculoides.

    Science.gov (United States)

    Ramirez, M Desmond; Oakley, Todd H

    2015-05-15

    Cephalopods are renowned for changing the color and pattern of their skin for both camouflage and communication. Yet, we do not fully understand how cephalopods control the pigmented chromatophore organs in their skin and change their body pattern. Although these changes primarily rely on eyesight, we found that light causes chromatophores to expand in excised pieces of Octopus bimaculoides skin. We call this behavior light-activated chromatophore expansion (or LACE). To uncover how octopus skin senses light, we used antibodies against r-opsin phototransduction proteins to identify sensory neurons that express r-opsin in the skin. We hypothesized that octopus LACE relies on the same r-opsin phototransduction cascade found in octopus eyes. By creating an action spectrum for the latency to LACE, we found that LACE occurred most quickly in response to blue light. We fit our action spectrum data to a standard opsin curve template and estimated the λmax of LACE to be 480 nm. Consistent with our hypothesis, the maximum sensitivity of the light sensors underlying LACE closely matches the known spectral sensitivity of opsin from octopus eyes. LACE in isolated preparations suggests that octopus skin is intrinsically light sensitive and that this dispersed light sense might contribute to their unique and novel patterning abilities. Finally, our data suggest that a common molecular mechanism for light detection in eyes may have been co-opted for light sensing in octopus skin and then used for LACE.

  2. Chromatophores and color revelation in the blue variant of the Siamese fighting fish (Betta splendens).

    Science.gov (United States)

    Amiri, M H; Shaheen, Huda M

    2012-02-01

    Our light and electron microscopy observations have revealed that the chromatic unit for the caudal fin in the blue variant of the Siamese fighting fish consists exclusively of dermal chromatophores comprised of compact and overlapping light-reflecting motile iridophores underlined by a layer of light absorbing melanophores. The 2 subtypes that make up about 70% of the skin tissue are located just below the basal layer of the considerably thin epidermis. The administration of K-rich saline or norepinephrine induced prompt, but gradual and reversible, changes in the color of the skin from blue to a brown-yellowish color. The induced color change is attributable either to the neurotransmitter releasing effects of the K-rich saline or to the direct effects of norepinephrine on the postsynaptic alpha adrenergic receptors. Both of these agents induced aggregation of the melanosomes within the melanophores and apparently shifted the wavelength of the light reflected by the iridophores towards the shorter (blue) end of the spectrum. Based on the distribution and architectural arrangement of the iridophores and melanophores as well as their physiological responses, we conclude that the generation of the blue coloration in this fish predominantly occurs through motile iridophores via a multilayered thin-film interference phenomenon of the non-ideal type. The presence of the underlying melanophores provides a black sheet of melanin that enhances the chroma and purity of the color.

  3. Integumental reddish-violet coloration owing to novel dichromatic chromatophores in the teleost fish, Pseudochromis diadema.

    Science.gov (United States)

    Goda, Makoto; Ohata, Mihoko; Ikoma, Hayato; Fujiyoshi, Yoshinori; Sugimoto, Masazumi; Fujii, Ryozo

    2011-08-01

    In the reddish-violet parts of the skin of the diadema pseudochromis Pseudochromis diadema, we found novel dichromatic chromatophores with a reddish pigment and reflecting platelets. We named these novel cells 'erythro-iridophores'. In standard physiological solution, erythro-iridophores displayed two hues, red and dark violet when viewed with an optical microscope under ordinary transmission light and epi-illumination optics, respectively. Under transmission electron microscopy, however, we observed no typical red chromatosomes, i.e., erythrosomes, in the cytoplasm. High-performance thin-layer chromatography (HPTLC) analysis of the pigment eluted from the erythro-iridophores indicated that carotenoid is the main pigment generating the reddish color. Furthermore, when the irrigating medium was a K(+)-rich saline solution, the color reflected from the erythro-iridophores changed from dark violet to sky blue, but the red coloration remained. The motile activities of the erythro-iridophores may participate in the changes in the reddish-violet shades of the pseudochromis fish.

  4. Pigment granule translocation in red ovarian chromatophores from the palaemonid shrimp Macrobrachium olfersi (Weigmann, 1836): functional roles for the cytoskeleton and its molecular motors.

    Science.gov (United States)

    Milograna, Sarah Ribeiro; Ribeiro, Márcia Regina; Baqui, Munira Muhammad Abdel; McNamara, John Campbell

    2014-12-01

    The binding of red pigment concentrating hormone (RPCH) to membrane receptors in crustacean chromatophores triggers Ca²⁺/cGMP signaling cascades that activate cytoskeletal motors, driving pigment granule translocation. We investigate the distributions of microfilaments and microtubules and their associated molecular motors, myosin and dynein, by confocal and transmission electron microscopy, evaluating a functional role for the cytoskeleton in pigment translocation using inhibitors of polymer turnover and motor activity in vitro. Microtubules occupy the chromatophore cell extensions whether the pigment granules are aggregated or dispersed. The inhibition of microtubule turnover by taxol induces pigment aggregation and inhibits re-dispersion. Phalloidin-FITC actin labeling, together with tannic acid fixation and ultrastructural analysis, reveals that microfilaments form networks associated with the pigment granules. Actin polymerization induced by jasplaquinolide strongly inhibits RPCH-induced aggregation, causes spontaneous pigment dispersion, and inhibits pigment re-dispersion. Inhibition of actin polymerization by latrunculin-A completely impedes pigment aggregation and re-dispersion. Confocal immunocytochemistry shows that non-muscle myosin II (NMMII) co-localizes mainly with pigment granules while blebbistatin inhibition of NMMII strongly reduces the RPCH response, also inducing spontaneous pigment dispersion. Myosin II and dynein also co-localize with the pigment granules. Inhibition of dynein ATPase by erythro-9-(2-hydroxy-3-nonyl) adenine induces aggregation, inhibits RPCH-triggered aggregation, and inhibits re-dispersion. Granule aggregation and dispersion depend mainly on microfilament integrity although microtubules may be involved. Both cytoskeletal polymers are functional only when subunit turnover is active. Myosin and dynein may be the molecular motors that drive pigment aggregation. These mechanisms of granule translocation in crustacean

  5. Early ontogeny of chromatophores and body color changes of Acanthopagrus schlegelii%黑棘鲷早期色素细胞发育与体色变化

    Institute of Scientific and Technical Information of China (English)

    于道德; 刘洪军; 关健; 王其翔; 官曙光; 周健

    2012-01-01

    对黑棘鲷早期发育过程中体色和色素细胞的分布及形态变化进行了连续观察.结果表明,黑棘鲷幼体黑色素在原口关闭前期开始出现,黄色素在嗅囊期出现,彩虹色素出现较晚,孵化后6d(Day post hatching,dph)在眼球上端出现,而后密集于腹腔(28 dph)以及鳃盖骨附近(32 dph).黑色素细胞在发育过程中,不仅数量增多,而且形状也由点状逐渐变成以树枝状和雪花状为主,为幼体黑色素的发育过程;28 dph幼体黑色素完全被成体黑色素替代,形态上再次变为小点状.黄色素几乎伴随着黑色素的分布,色素细胞几乎无形态变化,最终被黑色素覆盖而不明显.初孵仔鱼,尾端6~8体节躯干部具有黑色素丛,构成了该鱼的种属特征.在28 dph,体色发育进入到模式形成期,首先在躯干部形成相互间隔的3个色素带,至40 dph共7条色素带形成,完成体色的模式发育.%The morphological characteristics and distribution of chromatophores, as well as body color changes during early life history(0~40dph) of Acanthopagrus schlegelii were observed and photographed. The larval melanophores occurred firstly at blastopore colsure stage. Larval xanthophores occurred at olfactory vesicle stage, and iridophores at 6dph on the upper side of eye, then on the abdominal cavity (28dph) and around the opercle (32dph). Melanophores appeared as spots, then formed dendrites, and the number of cells with dendrites increased during the ontogenetic process. At 28dph, the larval melanophores were substituted by adult spotted melanophores. Xanthophores coocurred with the melanophores during the early ontogeny, then obscured due to the overlapping by melanophores with no obvious morphological changes during the en-tire study. Melanin aggregation at 6~8 segements from the tail in newly-hatched larvae became a special characteristics of this species. At 28dph, the larval body color developed into the pattern formation stage, and

  6. SPECTRAL IDENTIFICATION OF THE ELECTROCHROMICALLY ACTIVE CAROTENOIDS OF RHODOBACTER-SPHAEROIDES IN CHROMATOPHORES AND RECONSTITUTED LIPOSOMES

    NARCIS (Netherlands)

    CRIELAARD, W; VANMOURIK, F; VANGRONDELLE, R; KONINGS, WN; HELLINGWERF, KJ

    1992-01-01

    Reaction centers with both light harvesting complexes I and II (B875 and B800/850; i.e., RCLH(I)LH(II) complexes) have been isolated from Rhodobacter sphaeroides. These complexes have been incorporated into liposomes made from lipids purified from Escherichia coli. The electrochromic bandshift of ca

  7. Identification of chromatophore membrane protein complexes formed under different nitrogen availability conditions in Rhodospirillum rubrum

    DEFF Research Database (Denmark)

    Selao, Tiago Toscano; Branca, Rui; Chae, Pil Seok

    2011-01-01

    expressed proteins, such as subunits of the succinate dehydrogenase complex and other TCA cycle enzymes that are usually found in the cytosol, thus hinting at a possible association to the membrane in response to nitrogen deficiency. We propose a redox sensing mechanism that can influence the membrane...

  8. Role of catecholamines and nitric oxide on pigment displacement of the chromatophores of freshwater snakehead teleost fish, Channa punctatus.

    Science.gov (United States)

    Biswas, Saikat P; Jadhao, Arun G; Palande, Nikhil V

    2014-04-01

    We are reporting for the first time that the catecholamines (adrenaline and noradrenaline) inhibit the effect of nitric oxide (NO) on melanosome dispersion in freshly isolated scales of the freshwater snakehead fish, Channa punctatus. We studied the effect of NO and catecholamines on the pigment displacement by observing the changes in the melanophore index. The scales when treated with solution containing NO donor sodium nitroprusside (SNP) showed dispersion of melanosomes, whereas NO synthase blocker N-omega-Nitro-L-arginine suppresses this action of SNP. Treatment with adrenaline and noradrenaline on the isolated scales caused aggregation of melanosomes. Scales treated with solution containing catecholamines and SNP resulted in aggregation of melanosomes suggesting that catecholamines mask the effect of SNP. These results suggest that the catecholamines are inhibiting the effect of NO and causing the aggregation of the melanosomes may be via surface receptors.

  9. The pigmentary system of developing axolotls. I. A biochemical and structural analysis of chromatophores in wild-type axolotls.

    Science.gov (United States)

    Frost, S K; Epp, L G; Robinson, S J

    1984-06-01

    A biochemical and transmission electron microscopic description of the wild-type pigment phenotype in developing Mexican axolotls (Ambystoma mexicanum) is presented. There are three pigment cell types found in adult axolotl skin - melanophores, xanthophores and iridophores. Both pigments and pigment cells undergo specific developmental changes in axolotls. Melanophores are the predominant pigment cell type throughout development; xanthophores occur secondarily and in fewer numbers than melanophores; iridophores do not appear until well into the larval stage and remain thereafter as the least frequently encountered pigment cell type. Ultrastructural differences in xanthophore organelle (pterinosome) structure at different developmental stages correlate with changes in the pattern of pteridine biosynthesis. Sepiapterin, a yellow pteridine, is present in larval axolotl skin but not in adults. Riboflavin (also yellow) is present in minimal quantities in larval skin and large quantities in adult axolotl skin. Pterinosomes undergo a morphological "reversion" at some point prior to or shortly after axolotls attain sexual maturity. Correlated with the neotenic state of the axolotl, certain larval pigmentary features are retained throughout development. Notably, the pigment cells remain scattered in the dermis such that no two pigment cell bodies overlap, although cell processes may overlap. This study forms the basis for comparison of the wild type pigment phenotype to the three mutant phenotypes-melanoid, axanthic and albino-found in the axolotl.

  10. Proton transfer from the bulk to the bound ubiquinone QB of the reaction center in chromatophores of Rhodobacter sphaeroides: Retarded conveyance by neutral water

    Science.gov (United States)

    Gopta, Oksana A.; Cherepanov, Dmitry A.; Junge, Wolfgang; Mulkidjanian, Armen Y.

    1999-01-01

    The mechanism of proton transfer from the bulk into the membrane protein interior was studied. The light-induced reduction of a bound ubiquinone molecule QB by the photosynthetic reaction center is accompanied by proton trapping. We used kinetic spectroscopy to measure (i) the electron transfer to QB (at 450 nm), (ii) the electrogenic proton delivery from the surface to the QB site (by electrochromic carotenoid response at 524 nm), and (iii) the disappearance of protons from the bulk solution (by pH indicators). The electron transfer to QB− and the proton-related electrogenesis proceeded with the same time constant of ≈100 μs (at pH 6.2), whereas the alkalinization in the bulk was distinctly delayed (τ ≈ 400 μs). We investigated the latter reaction as a function of the pH indicator concentration, the added pH buffers, and the temperature. The results led us to the following conclusions: (i) proton transfer from the surface-located acidic groups into the QB site followed the reduction of QB without measurable delay; (ii) the reprotonation of these surface groups by pH indicators and hydronium ions was impeded, supposedly, because of their slow diffusion in the surface water layer; and (iii) as a result, the protons were slowly donated by neutral water to refill the proton vacancies at the surface. It is conceivable that the same mechanism accounts for the delayed relaxation of the surface pH changes into the bulk observed previously with bacteriorhodopsin membranes and thylakoids. Concerning the coupling between proton pumps in bioenergetic membranes, our results imply a tendency for the transient confinement of protons at the membrane surface. PMID:10557290

  11. Regulation of pigment migration in the amphibian melanophore

    NARCIS (Netherlands)

    Burgers, A.C.J.; Oordt, G.J. van

    1962-01-01

    Among vertebrates rapid color changes in the skin are restricted to fishes, amphibia and reptiles. These reactions are based on the movements of pigment granules in special cells, the chromatophores which may be classified as leucophores, xanthophores, erythrophores and melanophores.

  12. RNase P RNA from the Recently Evolved Plastid of Paulinella and from Algae

    Directory of Open Access Journals (Sweden)

    Pilar Bernal-Bayard

    2014-11-01

    Full Text Available The RNase P RNA catalytic subunit (RPR encoded in some plastids has been found to be functionally defective. The amoeba Paulinella chromatophora contains an organelle (chromatophore that is derived from the recent endosymbiotic acquisition of a cyanobacterium, and therefore represents a model of the early steps in the acquisition of plastids. In contrast with plastid RPRs the chromatophore RPR retains functionality similar to the cyanobacterial enzyme. The chromatophore RPR sequence deviates from consensus at some positions but those changes allow optimal activity compared with mutated chromatophore RPR with the consensus sequence. We have analyzed additional RPR sequences identifiable in plastids and have found that it is present in all red algae and in several prasinophyte green algae. We have assayed in vitro a subset of the plastid RPRs not previously analyzed and confirm that these organelle RPRs lack RNase P activity in vitro.

  13. X-ray structure, thermodynamics, elastic properties and MD simulations of cardiolipin/dimyristoylphosphatidylcholine mixed membranes

    DEFF Research Database (Denmark)

    Boscia, Alexander L.; Treece, Bradley W.; Mohammadyani, Dariush

    2014-01-01

    Cardiolipins (CLs) are important biologically for their unique role in biomembranes that couple phosphorylation and electron transport like bacterial plasma membranes, chromatophores, chloroplasts and mitochondria. CLs are often tightly coupled to proteins involved in oxidative phosphorylation. T...

  14. Protein translocons in photosynthetic organelles of Paulinella chromatophora

    Directory of Open Access Journals (Sweden)

    Przemysław Gagat

    2014-12-01

    Full Text Available The rhizarian amoeba Paulinella chromatophora harbors two photosynthetic cyanobacterial endosymbionts (chromatophores, acquired independently of primary plastids of glaucophytes, red algae and green plants. These endosymbionts have lost many essential genes, and transferred substantial number of genes to the host nuclear genome via endosymbiotic gene transfer (EGT, including those involved in photosynthesis. This indicates that, similar to primary plastids, Paulinella endosymbionts must have evolved a transport system to import their EGT-derived proteins. This system involves vesicular trafficking to the outer chromatophore membrane and presumably a simplified Tic-like complex at the inner chromatophore membrane. Since both sequenced Paulinella strains have been shown to undergo differential plastid gene losses, they do not have to possess the same set of Toc and Tic homologs. We searched the genome of Paulinella FK01 strain for potential Toc and Tic homologs, and compared the results with the data obtained for Paulinella CCAC 0185 strain, and 72 cyanobacteria, eight Archaeplastida as well as some other bacteria. Our studies revealed that chromatophore genomes from both Paulinella strains encode the same set of translocons that could potentially create a simplified but fully-functional Tic-like complex at the inner chromatophore membranes. The common maintenance of the same set of translocon proteins in two Paulinella strains suggests a similar import mechanism and/or supports the proposed model of protein import. Moreover, we have discovered a new putative Tic component, Tic62, a redox sensor protein not identified in previous comparative studies of Paulinella translocons.

  15. Fluorescence biosensor based on CdTe quantum dots for specific detection of H5N1 avian influenza virus

    Science.gov (United States)

    Hoa Nguyen, Thi; Dieu Thuy Ung, Thi; Hien Vu, Thi; Tran, Thi Kim Chi; Quyen Dong, Van; Khang Dinh, Duy; Liem Nguyen, Quang

    2012-09-01

    This report highlights the fabrication of fluorescence biosensors based on CdTe quantum dots (QDs) for specific detection of H5N1 avian influenza virus. The core biosensor was composed of (i) the highly luminescent CdTe/CdS QDs, (ii) chromatophores extracted from bacteria Rhodospirillum rubrum, and (iii) the antibody of β-subunit. This core part was linked to the peripheral part of the biosensor via a biotin-streptavidin-biotin bridge and finally connected to the H5N1 antibody to make it ready for detecting H5N1 avian influenza virus. Detailed studies of each constituent were performed showing the image of QDs-labeled chromatophores under optical microscope, proper photoluminescence (PL) spectra of CdTe/CdS QDs, chromatophores and the H5N1 avian influenza viruses.

  16. Effects of the Medium Composition on the Components of the Electrochemical Proton Gradient in Rhodopseudomonas sphaeroides

    NARCIS (Netherlands)

    Michels, Paul A.M.; Hellingwerf, K; Lolkema, Juke S.; Friedberg, Ilan; Konings, Wilhelmus

    1981-01-01

    The magnitude and composition of the proton motive force (Δµ~H+) has been measured in chromatophores and whole cells of Rhodopseudomonas sphaeroides as a function of the ionic composition of the buffer in which the energy-transducing membranes are suspended. Measurements with the flow-dialysis techn

  17. Improvement of Bioactive Compound Classification through Integration of Orthogonal Cell-Based Biosensing Methods

    Directory of Open Access Journals (Sweden)

    Goran N. Jovanovic

    2007-01-01

    Full Text Available Lack of specificity for different classes of chemical and biological agents, and false positives and negatives, can limit the range of applications for cell-based biosensors. This study suggests that the integration of results from algal cells (Mesotaenium caldariorum and fish chromatophores (Betta splendens improves classification efficiency and detection reliability. Cells were challenged with paraquat, mercuric chloride, sodium arsenite and clonidine. The two detection systems were independently investigated for classification of the toxin set by performing discriminant analysis. The algal system correctly classified 72% of the bioactive compounds, whereas the fish chromatophore system correctly classified 68%. The combined classification efficiency was 95%. The algal sensor readout is based on fluorescence measurements of changes in the energy producing pathways of photosynthetic cells, whereas the response from fish chromatophores was quantified using optical density. Change in optical density reflects interference with the functioning of cellular signal transduction networks. Thus, algal cells and fish chromatophores respond to the challenge agents through sufficiently different mechanisms of action to be considered orthogonal.

  18. Aspidoras mephisto, new species: The first troglobitic Callichthyidae (Teleostei: Siluriformes) from South America

    Science.gov (United States)

    Bichuette, Maria Elina

    2017-01-01

    Aspidoras mephisto n. sp. is described from the Anésio-Russão cave system, upper Tocantins River basin, Goiás, Brazil. The species can be readily distinguished from its congeners by troglomorphic features and also by presenting the following combination of features: infraorbital 1 generally with well-developed ventral laminar; or moderately developed; poorly-developed serrations on posterior margin of pectoral spine; nuchal plate not externally visible; dorsal fin, even in conspicuously colored specimens, with only dark brown or black chromatophores concentrated on rays, forming spots in some specimens; membranes hyaline; or sparse dark brown or black chromatophores on membranes, not forming any conspicuous pattern; and inner laminar expansion of infraorbital 1 moderately developed. Information about its habitat, ecology, behaviour and conservation status are provided and also a brief description of the juvenile stage. PMID:28248959

  19. The lantern shark's light switch: turning shallow water crypsis into midwater camouflage.

    Science.gov (United States)

    Claes, Julien M; Mallefet, Jérôme

    2010-10-23

    Bioluminescence is a common feature in the permanent darkness of the deep-sea. In fishes, light is emitted by organs containing either photogenic cells (intrinsic photophores), which are under direct nervous control, or symbiotic luminous bacteria (symbiotic photophores), whose light is controlled by secondary means such as mechanical occlusion or physiological suppression. The intrinsic photophores of the lantern shark Etmopterus spinax were recently shown as an exception to this rule since they appear to be under hormonal control. Here, we show that hormones operate what amounts to a unique light switch, by acting on a chromatophore iris, which regulates light emission by pigment translocation. This result strongly suggests that this shark's luminescence control originates from the mechanism for physiological colour change found in shallow water sharks that also involves hormonally controlled chromatophores: the lantern shark would have turned the initial shallow water crypsis mechanism into a midwater luminous camouflage, more efficient in the deep-sea environment.

  20. Proteinaceous Light Diffusers and Dynamic 3D Skin Texture in Cephalopods

    Science.gov (United States)

    2014-02-24

    characterize leucophore reflectance properties (spectral reflectance UV-IR, polarization, diffusing properties) in cephalopod and fish species. Aim 2...contrast pattern. B. Close up of the bold zebra -stripe pattern and the white fin spots located at the bottom of the image. C. Micrograph of a single...in the activation of other skin structures in cephalopods and fish (chromatophores and/or iridophores): serotonin (5-HT; relaxes cephalopod

  1. Eviota piperata, a new gobiid species from Palau (Teleostei: Gobiidae).

    Science.gov (United States)

    Greenfield, David W; Winterbottom, Richard

    2014-01-22

    A new species of dwarfgoby, Eviota piperata is described from Palau. It belongs to the cephalic sensory-pore system Group II (lacking only the IT pore); has a dorsal/anal-fin formula of 8/8; has some pectoral-fin rays branched; no dark spot over the ural centrum; the male genital papilla is not fimbriate; and the cheek and body are heavily peppered with chromatophores.

  2. Physiological response of the Caribbean Coral O. annularis to Pollution Gradients

    Science.gov (United States)

    Murphy, E. L.; Sivaguru, M.; Fouke, B. W.

    2014-12-01

    Orbicella annularis is an abundant ecological cornerstone framework-building Scleractinian coral throughout the Caribbean Sea. The O. annularis holobiont (biotic and abiotic components of the coral) is negatively impacted by increased exposure to anthropogenic pollution. This is consistently evidenced by altered tissue cellular composition, and skeletal structure. The O. annularis' holobiont is weakened by increased exposure to sewage and ship bilge pollution. Pollution exposure is characterized by decreased skeletal growth, as well as decreased zooxanthellae and chromatophore tissue cell densities. Healthy colonies studied at five sites on the leeward coast of Curacao, along a systematically decreasing pollution concentration, were sampled from the back-reef depositional facies of a protected fringing reef tract. A unidirectional oceanographic current flows to the NW past the city of Willemstad, a large point source of human sewage and ship bilge. This setting creates an ideal natural laboratory for in situ experimentation that quantitatively tracks the impact to coral physiology along a gradient from unimpacted to polluted seawater. Our lab has established laser scanning microscopy for three-dimensional (3D) quantification of zooxanthellae, and chromatophore cellular tissue density. X-ray computed tomography (BioCT) was used for analysis of skeletal density. Zooxanthellae density decreased as pollution concentration increased. Chromatophore density showed no significant relationship with pollution concentration but varied dramatically within each site. This suggests zooxanthellae density is highly impacted by environmental stress while variation in chromatophore density is driven by genetic variation. These results will be used to create a new model for environmental impacts on coral physiology and skeletal growth.

  3. Mechanisms and behavioural functions of structural coloration in cephalopods

    OpenAIRE

    Mäthger, Lydia M.; Denton, Eric J.; Marshall, N. Justin; Hanlon, Roger T.

    2008-01-01

    Octopus, squid and cuttlefish are renowned for rapid adaptive coloration that is used for a wide range of communication and camouflage. Structural coloration plays a key role in augmenting the skin patterning that is produced largely by neurally controlled pigmented chromatophore organs. While most iridescence and white scattering is produced by passive reflectance or diffusion, some iridophores in squid are actively controlled via a unique cholinergic, non-synaptic neural system. We review t...

  4. Ionic liquids effects on the permeability of photosynthetic membranes probed by the electrochromic shift of endogenous carotenoids.

    Science.gov (United States)

    Malferrari, Marco; Malferrari, Danilo; Francia, Francesco; Galletti, Paola; Tagliavini, Emilio; Venturoli, Giovanni

    2015-11-01

    Ionic liquids (ILs) are promising materials exploited as solvents and media in many innovative applications, some already used at the industrial scale. The chemical structure and physicochemical properties of ILs can differ significantly according to the specific applications for which they have been synthesized. As a consequence, their interaction with biological entities and toxicity can vary substantially. To select highly effective and minimally harmful ILs, these properties need to be investigated. Here we use the so called chromatophores--protein-phospholipid membrane vesicles obtained from the photosynthetic bacterium Rhodobacter sphaeroides--to assess the effects of imidazolinium and pyrrolidinium ILs, with chloride or dicyanamide as counter anions, on the ionic permeability of a native biological membrane. The extent and modalities by which these ILs affect the ionic conductivity can be studied in chromatophores by analyzing the electrochromic response of endogenous carotenoids, acting as an intramembrane voltmeter at the molecular level. We show that chromatophores represent an in vitro experimental model suitable to probe permeability changes induced in cell membranes by ILs differing in chemical nature, degree of oxygenation of the cationic moiety and counter anion.

  5. Evolving a photosynthetic organelle

    Directory of Open Access Journals (Sweden)

    Nakayama Takuro

    2012-04-01

    Full Text Available Abstract The evolution of plastids from cyanobacteria is believed to represent a singularity in the history of life. The enigmatic amoeba Paulinella and its 'recently' acquired photosynthetic inclusions provide a fascinating system through which to gain fresh insight into how endosymbionts become organelles. The plastids, or chloroplasts, of algae and plants evolved from cyanobacteria by endosymbiosis. This landmark event conferred on eukaryotes the benefits of photosynthesis - the conversion of solar energy into chemical energy - and in so doing had a huge impact on the course of evolution and the climate of Earth 1. From the present state of plastids, however, it is difficult to trace the evolutionary steps involved in this momentous development, because all modern-day plastids have fully integrated into their hosts. Paulinella chromatophora is a unicellular eukaryote that bears photosynthetic entities called chromatophores that are derived from cyanobacteria and has thus received much attention as a possible example of an organism in the early stages of organellogenesis. Recent studies have unlocked the genomic secrets of its chromatophore 23 and provided concrete evidence that the Paulinella chromatophore is a bona fide photosynthetic organelle 4. The question is how Paulinella can help us to understand the process by which an endosymbiont is converted into an organelle.

  6. How does the blue-ringed octopus (Hapalochlaena lunulata) flash its blue rings?

    Science.gov (United States)

    Mäthger, Lydia M; Bell, George R R; Kuzirian, Alan M; Allen, Justine J; Hanlon, Roger T

    2012-11-01

    The blue-ringed octopus (Hapalochlaena lunulata), one of the world's most venomous animals, has long captivated and endangered a large audience: children playing at the beach, divers turning over rocks, and biologists researching neurotoxins. These small animals spend much of their time in hiding, showing effective camouflage patterns. When disturbed, the octopus will flash around 60 iridescent blue rings and, when strongly harassed, bite and deliver a neurotoxin that can kill a human. Here, we describe the flashing mechanism and optical properties of these rings. The rings contain physiologically inert multilayer reflectors, arranged to reflect blue-green light in a broad viewing direction. Dark pigmented chromatophores are found beneath and around each ring to enhance contrast. No chromatophores are above the ring; this is unusual for cephalopods, which typically use chromatophores to cover or spectrally modify iridescence. The fast flashes are achieved using muscles under direct neural control. The ring is hidden by contraction of muscles above the iridophores; relaxation of these muscles and contraction of muscles outside the ring expose the iridescence. This mechanism of producing iridescent signals has not previously been reported in cephalopods and we suggest that it is an exceptionally effective way to create a fast and conspicuous warning display.

  7. Mechanisms and behavioural functions of structural coloration in cephalopods.

    Science.gov (United States)

    Mäthger, Lydia M; Denton, Eric J; Marshall, N Justin; Hanlon, Roger T

    2009-04-06

    Octopus, squid and cuttlefish are renowned for rapid adaptive coloration that is used for a wide range of communication and camouflage. Structural coloration plays a key role in augmenting the skin patterning that is produced largely by neurally controlled pigmented chromatophore organs. While most iridescence and white scattering is produced by passive reflectance or diffusion, some iridophores in squid are actively controlled via a unique cholinergic, non-synaptic neural system. We review the recent anatomical and experimental evidence regarding the mechanisms of reflection and diffusion of light by the different cell types (iridophores and leucophores) of various cephalopod species. The structures that are responsible for the optical effects of some iridophores and leucophores have recently been shown to be proteins. Optical interactions with the overlying pigmented chromatophores are complex, and the recent measurements are presented and synthesized. Polarized light reflected from iridophores can be passed through the chromatophores, thus enabling the use of a discrete communication channel, because cephalopods are especially sensitive to polarized light. We illustrate how structural coloration contributes to the overall appearance of the cephalopods during intra- and interspecific behavioural interactions including camouflage.

  8. Morphological and molecular characterization of dietary-induced pseudo-albinism during post-embryonic development of Solea senegalensis (Kaup, 1858.

    Directory of Open Access Journals (Sweden)

    Maria J Darias

    Full Text Available The appearance of the pseudo-albino phenotype was investigated in developing Senegalese sole (Solea senegalensis, Kaup 1858 larvae at morphological and molecular levels. In order to induce the development of pseudo-albinos, Senegalese sole larvae were fed Artemia enriched with high levels of arachidonic acid (ARA. The development of their skin pigmentation was compared to that of a control group fed Artemia enriched with a reference commercial product. The relative amount of skin melanophores, xanthophores and iridophores revealed that larval pigmentation developed similarly in both groups. However, results from different relative proportions, allocation patterns, shapes and sizes of skin chromatophores revealed changes in the pigmentation pattern between ARA and control groups from 33 days post hatching onwards. The new populations of chromatophores that should appear at post-metamorphosis were not formed in the ARA group. Further, spatial patterns of distribution between the already present larval xanthophores and melanophores were suggestive of short-range interaction that seemed to be implicated in the degradation of these chromatophores, leading to the appearance of the pseudo-albino phenotype. The expression profile of several key pigmentation-related genes revealed that melanophore development was promoted in pseudo-albinos without a sufficient degree of terminal differentiation, thus preventing melanogenesis. Present results suggest the potential roles of asip1 and slc24a5 genes on the down-regulation of trp1 expression, leading to defects in melanin production. Moreover, gene expression data supports the involvement of pax3, mitf and asip1 genes in the developmental disruption of the new post-metamorphic populations of melanophores, xanthophores and iridophores.

  9. Morphological and molecular characterization of dietary-induced pseudo-albinism during post-embryonic development of Solea senegalensis (Kaup, 1858).

    Science.gov (United States)

    Darias, Maria J; Andree, Karl B; Boglino, Anaïs; Rotllant, Josep; Cerdá-Reverter, José Miguel; Estévez, Alicia; Gisbert, Enric

    2013-01-01

    The appearance of the pseudo-albino phenotype was investigated in developing Senegalese sole (Solea senegalensis, Kaup 1858) larvae at morphological and molecular levels. In order to induce the development of pseudo-albinos, Senegalese sole larvae were fed Artemia enriched with high levels of arachidonic acid (ARA). The development of their skin pigmentation was compared to that of a control group fed Artemia enriched with a reference commercial product. The relative amount of skin melanophores, xanthophores and iridophores revealed that larval pigmentation developed similarly in both groups. However, results from different relative proportions, allocation patterns, shapes and sizes of skin chromatophores revealed changes in the pigmentation pattern between ARA and control groups from 33 days post hatching onwards. The new populations of chromatophores that should appear at post-metamorphosis were not formed in the ARA group. Further, spatial patterns of distribution between the already present larval xanthophores and melanophores were suggestive of short-range interaction that seemed to be implicated in the degradation of these chromatophores, leading to the appearance of the pseudo-albino phenotype. The expression profile of several key pigmentation-related genes revealed that melanophore development was promoted in pseudo-albinos without a sufficient degree of terminal differentiation, thus preventing melanogenesis. Present results suggest the potential roles of asip1 and slc24a5 genes on the down-regulation of trp1 expression, leading to defects in melanin production. Moreover, gene expression data supports the involvement of pax3, mitf and asip1 genes in the developmental disruption of the new post-metamorphic populations of melanophores, xanthophores and iridophores.

  10. Cuttlefish skin papilla morphology suggests a muscular hydrostatic function for rapid changeability.

    Science.gov (United States)

    Allen, Justine J; Bell, George R R; Kuzirian, Alan M; Hanlon, Roger T

    2013-06-01

    Coleoid cephalopods adaptively change their body patterns (color, contrast, locomotion, posture, and texture) for camouflage and signaling. Benthic octopuses and cuttlefish possess the capability, unique in the animal kingdom, to dramatically and quickly change their skin from smooth and flat to rugose and three-dimensional. The organs responsible for this physical change are the skin papillae, whose biomechanics have not been investigated. In this study, small dorsal papillae from cuttlefish (Sepia officinalis) were preserved in their retracted or extended state, and examined with a variety of histological techniques including brightfield, confocal, and scanning electron microscopy. Analyses revealed that papillae are composed of an extensive network of dermal erector muscles, some of which are arranged in concentric rings while others extend across each papilla's diameter. Like cephalopod arms, tentacles, and suckers, skin papillae appear to function as muscular hydrostats. The collective action of dermal erector muscles provides both movement and structural support in the absence of rigid supporting elements. Specifically, concentric circular dermal erector muscles near the papilla's base contract and push the overlying tissue upward and away from the mantle surface, while horizontally arranged dermal erector muscles pull the papilla's perimeter toward its center and determine its shape. Each papilla has a white tip, which is produced by structural light reflectors (leucophores and iridophores) that lie between the papilla's muscular core and the skin layer that contains the pigmented chromatophores. In extended papillae, the connective tissue layer appeared thinner above the papilla's apex than in surrounding areas. This result suggests that papilla extension might create tension in the overlying connective tissue and chromatophore layers, storing energy for elastic retraction. Numerous, thin subepidermal muscles form a meshwork between the chromatophore layer

  11. Chemoprofile and bioactivities of Taverniera cuneifolia (Roth) Arn.: a wild relative and possible substitute of Glycyrrhiza glabra L.

    Science.gov (United States)

    Zore, Gajanan B; Winston, Umakanth B; Surwase, Babasaheb S; Meshram, Nisha S; Sangle, V D; Kulkarni, Smita S; Mohan Karuppayil, S

    2008-04-01

    Chemoprofile of Taverniera cuneifolia (Roth) Arn. a wild relative of commercial licorice (Glycyrrhiza glabra L) is presented. Both T. cuneifolia and G. glabra L were found to be very similar phytochemically. At least eighteen chromatophores were found similar in both the plants including the sweetening principle, glycyrrhizin. The extracts of T. cuneifolia root, exhibited promising anti-inflammatory, anti-tumor, anti germ tube formation (in Candida albicans), protection from mutagen toxicity and cytotoxic activities comparable to that of G. glabra. In general, the results suggest that T. cuneifolia could be used as substitute of G. glabra.

  12. Behavior and Body Patterns of the Larger Pacific Striped Octopus.

    Science.gov (United States)

    Caldwell, Roy L; Ross, Richard; Rodaniche, Arcadio; Huffard, Christine L

    2015-01-01

    Over thirty years ago anecdotal accounts of the undescribed Larger Pacific Striped Octopus suggested behaviors previously unknown for octopuses. Beak-to-beak mating, dens shared by mating pairs, inking during mating and extended spawning were mentioned in publications, and enticed generations of cephalopod biologists. In 2012-2014 we were able to obtain several live specimens of this species, which remains without a formal description. All of the unique behaviors listed above were observed for animals in aquaria and are discussed here. We describe the behavior, body color patterns, and postures of 24 adults maintained in captivity. Chromatophore patterns of hatchlings are also shown.

  13. Behavior and Body Patterns of the Larger Pacific Striped Octopus.

    Directory of Open Access Journals (Sweden)

    Roy L Caldwell

    Full Text Available Over thirty years ago anecdotal accounts of the undescribed Larger Pacific Striped Octopus suggested behaviors previously unknown for octopuses. Beak-to-beak mating, dens shared by mating pairs, inking during mating and extended spawning were mentioned in publications, and enticed generations of cephalopod biologists. In 2012-2014 we were able to obtain several live specimens of this species, which remains without a formal description. All of the unique behaviors listed above were observed for animals in aquaria and are discussed here. We describe the behavior, body color patterns, and postures of 24 adults maintained in captivity. Chromatophore patterns of hatchlings are also shown.

  14. Bio-inspired artificial iridophores based on capillary origami: Fabrication and device characterization

    Science.gov (United States)

    Manakasettharn, Supone; Ashley Taylor, J.; Krupenkin, Tom N.

    2011-10-01

    Cephalopods have evolved complex optical mechanisms of dynamic skin color control based on mechanical actuation of micro-scale optical structures such as iridophores and chromatophores. In this work, we describe the design, fabrication, and characterization of bio-inspired artificial iridophores, which resemble microflowers with flexible reflective petals, based on capillary origami microstructures. Two methods of petal actuation have been demonstrated—one based on the electrowetting process and the other by volume change of the liquid droplet. These results were in good agreement with a model derived to characterize the actuation dynamics.

  15. Overall energy conversion efficiency of a photosynthetic vesicle.

    Science.gov (United States)

    Sener, Melih; Strumpfer, Johan; Singharoy, Abhishek; Hunter, C Neil; Schulten, Klaus

    2016-08-26

    The chromatophore of purple bacteria is an intracellular spherical vesicle that exists in numerous copies in the cell and that efficiently converts sunlight into ATP synthesis, operating typically under low light conditions. Building on an atomic-level structural model of a low-light-adapted chromatophore vesicle from Rhodobacter sphaeroides, we investigate the cooperation between more than a hundred protein complexes in the vesicle. The steady-state ATP production rate as a function of incident light intensity is determined after identifying quinol turnover at the cytochrome bc1 complex (cytb⁢c1) as rate limiting and assuming that the quinone/quinol pool of about 900 molecules acts in a quasi-stationary state. For an illumination condition equivalent to 1% of full sunlight, the vesicle exhibits an ATP production rate of 82 ATP molecules/s. The energy conversion efficiency of ATP synthesis at illuminations corresponding to 1%-5% of full sunlight is calculated to be 0.12-0.04, respectively. The vesicle stoichiometry, evolutionarily adapted to the low light intensities in the habitat of purple bacteria, is suboptimal for steady-state ATP turnover for the benefit of protection against over-illumination.

  16. Morphological Characters and Transcriptome Profiles Associated with Black Skin and Red Skin in Crimson Snapper (Lutjanus erythropterus).

    Science.gov (United States)

    Zhang, Yan-Ping; Wang, Zhong-Duo; Guo, Yu-Song; Liu, Li; Yu, Juan; Zhang, Shun; Liu, Shao-Jun; Liu, Chu-Wu

    2015-11-12

    In this study, morphology observation and illumina sequencing were performed on two different coloration skins of crimson snapper (Lutjanus erythropterus), the black zone and the red zone. Three types of chromatophores, melanophores, iridophores and xanthophores, were organized in the skins. The main differences between the two colorations were in the amount and distribution of the three chromatophores. After comparing the two transcriptomes, 9200 unigenes with significantly different expressions (ratio change ≥ 2 and q-value ≤ 0.05) were found, of which 5972 were up-regulated in black skin and 3228 were up-regulated in red skin. Through the function annotation, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of the differentially transcribed genes, we excavated a number of uncharacterized candidate pigment genes as well as found the conserved genes affecting pigmentation in crimson snapper. The patterns of expression of 14 pigment genes were confirmed by the Quantitative real-time PCR analysis between the two color skins. Overall, this study shows a global survey of the morphological characters and transcriptome analysis of the different coloration skins in crimson snapper, and provides valuable cellular and genetic information to uncover the mechanism of the formation of pigment patterns in snappers.

  17. The biological mechanisms and behavioral functions of opsin-based light detection by the skin

    Directory of Open Access Journals (Sweden)

    Jennifer L Kelley

    2016-08-01

    Full Text Available Light detection not only forms the basis of vision (via visual retinal photoreceptors, but can also occur in other parts of the body, including many non-rod/non-cone ocular cells, the pineal complex, the deep brain, and the skin. Indeed, many of the photopigments (an opsin linked to a light-sensitive 11-cis retinal chromophore that mediate color vision in the eyes of vertebrates are also present in the skin of animals such as reptiles, amphibians, crustaceans and fishes (with related photoreceptive molecules present in cephalopods, providing a localized mechanism for light detection across the surface of the body. This form of non-visual photosensitivity may be particularly important for animals that can change their coloration by altering the dispersion of pigments within the chromatophores (pigment containing cells of the skin. Thus, skin coloration may be directly color matched or tuned to both the luminance and spectral properties of the local background environment, thereby facilitating behavioral functions such as camouflage, thermoregulation, and social signaling. This review examines the diversity and sensitivity of opsin-based photopigments present in the skin and considers their putative functional roles in mediating animal behavior. Furthermore, it discusses the potential underlying biochemical and molecular pathways that link shifts in environmental light to both photopigment expression and chromatophore photoresponses. Although photoreception that occurs independently of image formation remains poorly understood, this review highlights the important role of non-visual light detection in facilitating the multiple functions of animal coloration.

  18. Analogue of Melanotan II (MTII): A Novel Melanotropin with Superpotent Action on Frog Skin.

    Science.gov (United States)

    Gao, Liqian; Yu, Zhiqiang; Meng, Dan; Zheng, Fang; Ong, Yong S; Miao, Peng; Lee, Su S; Wen, Longping

    2015-01-01

    An α-MSH peptide analogue, named MTII (Ac-Nle-c[Asp-His-D-Phe-Arg-Trp-Lys]- NH2), is one of the most important ligands of melanotropic receptors but are relatively nonselective. In order to improve the melanotropic activities of the well-characterized MTII analogues, we report here a new analogue by modifying the core structure as well as the size of the cyclic region of MTII peptide. The analogue peptide, Ac-Nle-c[Asp-His-D-Phe-Lys-Trp-Gly-Lys]-OH (F Peptide), in which we replaced Arg at position 8 with Lys and added a Gly to position 10 of the MTII peptide sequence, was synthesized and used as a new melanotropic hormone in controlling rapid color changes in frogs by its actions on mobilizing pigment granule movements within chromatophores. The in vivo responses of chromatophores to MTII and the related analogue F Peptide were studied in frogs. The results show that the F Peptide was a superpotent agonist with similar melanotropic activity to the MTII peptide according to MTII peptide by in vivo studies. The analogue also exhibited ultraprolonged melanotropic activity. The F peptide can be useful in the study of numerous physiological processes, particularly when superpotent and prolonged melanotropic activity is desired.

  19. Morphological Characters and Transcriptome Profiles Associated with Black Skin and Red Skin in Crimson Snapper (Lutjanus erythropterus

    Directory of Open Access Journals (Sweden)

    Yan-Ping Zhang

    2015-11-01

    Full Text Available In this study, morphology observation and illumina sequencing were performed on two different coloration skins of crimson snapper (Lutjanus erythropterus, the black zone and the red zone. Three types of chromatophores, melanophores, iridophores and xanthophores, were organized in the skins. The main differences between the two colorations were in the amount and distribution of the three chromatophores. After comparing the two transcriptomes, 9200 unigenes with significantly different expressions (ratio change ≥ 2 and q-value ≤ 0.05 were found, of which 5972 were up-regulated in black skin and 3228 were up-regulated in red skin. Through the function annotation, Gene Ontology (GO and Kyoto Encyclopedia of Genes and Genomes (KEGG pathway analysis of the differentially transcribed genes, we excavated a number of uncharacterized candidate pigment genes as well as found the conserved genes affecting pigmentation in crimson snapper. The patterns of expression of 14 pigment genes were confirmed by the Quantitative real-time PCR analysis between the two color skins. Overall, this study shows a global survey of the morphological characters and transcriptome analysis of the different coloration skins in crimson snapper, and provides valuable cellular and genetic information to uncover the mechanism of the formation of pigment patterns in snappers.

  20. Reconstructing Carotenoid-Based and Structural Coloration in Fossil Skin.

    Science.gov (United States)

    McNamara, Maria E; Orr, Patrick J; Kearns, Stuart L; Alcalá, Luis; Anadón, Pere; Peñalver, Enrique

    2016-04-25

    Evidence of original coloration in fossils provides insights into the visual communication strategies used by ancient animals and the functional evolution of coloration over time [1-7]. Hitherto, all reconstructions of the colors of reptile integument and the plumage of fossil birds and feathered dinosaurs have been of melanin-based coloration [1-6]. Extant animals also use other mechanisms for producing color [8], but these have not been identified in fossils. Here we report the first examples of carotenoid-based coloration in the fossil record, and of structural coloration in fossil integument. The fossil skin, from a 10 million-year-old colubrid snake from the Late Miocene Libros Lagerstätte (Teruel, Spain) [9, 10], preserves dermal pigment cells (chromatophores)-xanthophores, iridophores, and melanophores-in calcium phosphate. Comparison with chromatophore abundance and position in extant reptiles [11-15] indicates that the fossil snake was pale-colored in ventral regions; dorsal and lateral regions were green with brown-black and yellow-green transverse blotches. Such coloration most likely functioned in substrate matching and intraspecific signaling. Skin replicated in authigenic minerals is not uncommon in exceptionally preserved fossils [16, 17], and dermal pigment cells generate coloration in numerous reptile, amphibian, and fish taxa today [18]. Our discovery thus represents a new means by which to reconstruct the original coloration of exceptionally preserved fossil vertebrates.

  1. An ethogram for Benthic Octopods (Cephalopoda: Octopodidae).

    Science.gov (United States)

    Mather, Jennifer A; Alupay, Jean S

    2016-05-01

    The present paper constructs a general ethogram for the actions of the flexible body as well as the skin displays of octopuses in the family Octopodidae. The actions of 6 sets of structures (mantle-funnel, arms, sucker-stalk, skin-web, head, and mouth) combine to produce behavioral units that involve positioning of parts leading to postures such as the flamboyant, movements of parts of the animal with relation to itself including head bob and grooming, and movements of the whole animal by both jetting in the water and crawling along the substrate. Muscular actions result in 4 key changes in skin display: (a) chromatophore expansion, (b) chromatophore contraction resulting in appearance of reflective colors such as iridophores and leucophores, (c) erection of papillae on the skin, and (d) overall postures of arms and mantle controlled by actions of the octopus muscular hydrostat. They produce appearances, including excellent camouflage, moving passing cloud and iridescent blue rings, with only a few known species-specific male visual sexual displays. Commonalities across the family suggest that, despite having flexible muscular hydrostat movement systems producing several behavioral units, simplicity of production may underlie the complexity of movement and appearance. This systematic framework allows researchers to take the next step in modeling how such diversity can be a combination of just a few variables. (PsycINFO Database Record

  2. Overall energy conversion efficiency of a photosynthetic vesicle

    Science.gov (United States)

    Sener, Melih; Strumpfer, Johan; Singharoy, Abhishek; Hunter, C Neil; Schulten, Klaus

    2016-01-01

    The chromatophore of purple bacteria is an intracellular spherical vesicle that exists in numerous copies in the cell and that efficiently converts sunlight into ATP synthesis, operating typically under low light conditions. Building on an atomic-level structural model of a low-light-adapted chromatophore vesicle from Rhodobacter sphaeroides, we investigate the cooperation between more than a hundred protein complexes in the vesicle. The steady-state ATP production rate as a function of incident light intensity is determined after identifying quinol turnover at the cytochrome bc1 complex (cytb⁢c1) as rate limiting and assuming that the quinone/quinol pool of about 900 molecules acts in a quasi-stationary state. For an illumination condition equivalent to 1% of full sunlight, the vesicle exhibits an ATP production rate of 82 ATP molecules/s. The energy conversion efficiency of ATP synthesis at illuminations corresponding to 1%–5% of full sunlight is calculated to be 0.12–0.04, respectively. The vesicle stoichiometry, evolutionarily adapted to the low light intensities in the habitat of purple bacteria, is suboptimal for steady-state ATP turnover for the benefit of protection against over-illumination. DOI: http://dx.doi.org/10.7554/eLife.09541.001 PMID:27564854

  3. Two new dwarfgobies of the genus Eviota from the Ryukyu Islands, Japan (Teleostei: Gobiidae).

    Science.gov (United States)

    Greenfield, David W; Suzuki, Toshiyuki; Shibukawa, Koichi

    2014-03-10

    Two species of dwarfgoby are described from the Ryukyu Islands, Japan. Eviota flebilis n. sp. belongs to cephalic sensory-pore system pattern 2 (lacking only IT pore), has a dorsal/anal fin-ray formula of 8/7, unbranched pectoral-fin rays, the 5th pelvic-fin ray 12.9% of the 4th, a distinctive narrow, red-orange line under the eye, and a dark vertical line at the caudal-fin base. Eviota specca n. sp. has a cephalic sensory-pore system pattern 1 (complete), has a dorsal/anal-fin formula of 8/8, the body heavily sprinkled with chromatophores, and a single dark spot on the upper pectoral-fin base.

  4. Origins of adult pigmentation: diversity in pigment stem cell lineages and implications for pattern evolution.

    Science.gov (United States)

    Parichy, David M; Spiewak, Jessica E

    2015-01-01

    Teleosts comprise about half of all vertebrate species and exhibit an extraordinary diversity of adult pigment patterns that function in shoaling, camouflage, and mate choice and have played important roles in speciation. Here, we review studies that have identified several distinct neural crest lineages, with distinct genetic requirements, that give rise to adult pigment cells in fishes. These lineages include post-embryonic, peripheral nerve-associated stem cells that generate black melanophores and iridescent iridophores, cells derived directly from embryonic neural crest cells that generate yellow-orange xanthophores, and bipotent stem cells that generate both melanophores and xanthophores. This complexity in adult chromatophore lineages has implications for our understanding of adult traits, melanoma, and the evolutionary diversification of pigment cell lineages and patterns.

  5. Cirolana songkhla, a new species of brackish-water cirolanid isopod (Crustacea, Isopoda, Cirolanidae from the lower Gulf of Thailand

    Directory of Open Access Journals (Sweden)

    Eknarin Rodcharoen

    2014-01-01

    Full Text Available Cirolana songkhla sp. n. was collected from brackish-water habitats including lagoons and estuaries in the coastal zone of the lower Gulf of Thailand. C. songkhla sp. n. is described and fully illustrated; C. songkhla sp. n. can be recognized by the presence of abundant chromatophores dorsally, lack of ornamentation on the posterior pereonites, pleonites and pleotelson, the number of robust setae on the uropodal and pleotelson margins (uropod exopod lateral margin with 12–14 RS, mesial margin with 5–8 RS; endopod lateral margin with 8–10 RS, mesial margin with 11–13 RS; pleotelson with 12–15 RS and lack of setae on the endopods of pleopods 3–5. A dichotomous key of brackish Cirolana species in Thailand is given.

  6. A new species of Helobdella (Hirudinida: Glossiphoniidae) from Oregon

    Science.gov (United States)

    Moser, William E.; Fend, Steven V.; Richardson, Dennis J.; Hammond, Charlette I.; Lazo-Wasem, Eric A.; Govedich, Fredric R.; Gullo, Bettina S.

    2013-01-01

    Helobdella bowermani n. sp. is described from specimens collected in fine sediment of open water benthos of Upper Klamath Lake, Klamath County, Oregon. The new species has pale yellow/buff coloration with scattered chromatophore blotches throughout the dorsal surface, lateral extensions or papillae only on the a2 annulus, dorsal medial row of papillae with small papilla on a1 and larger papillae on a2 and a3, and a small oval scute (rarely triangular). Helobdella bowermani n. sp. is morphologically similar to Helobdella atli and Helobdella simplex. Molecular comparison of CO-I sequence data from H. bowermani n. sp. revealed differences of 10.6%–10.8% with Helobdella californica, differences of 12.2%–13.7% with H. atli, and differences of 12.7%–13.2% with H. simplex.

  7. Highly sensitive detection of NT-proBNP by molecular motor

    Directory of Open Access Journals (Sweden)

    Jie Zhang

    2017-03-01

    Full Text Available FoF1-ATPase is an active rotary motor, and generates three-ATP for each rotation. At saturated substrate concentration, the motor can achieve about 103 r.p.m, which means one motor can generate about 105 ATP molecules during 30 min. Here, we constituted a novel nanodevice with a molecular rotary motor and a “battery”, FoF1-ATPase and chromatophore, and presented a novel method of sandwich type rotary biosensor based on ε subunit with one target-to-one motor, in which one target corresponds 105 ATP molecules as detection signals during 30 min. The target such as NT-proBNP detection demonstrated that this novel nanodevice has potential to be developed into an ultrasensitive biosensor to detect low expressed targets.

  8. Embryology of the spider crabs Leurocyclus tuberculosus (H. Milne-Edwards & Lucas 1842) and Libinia spinosa (H. Milne-Edwards 1834) (Brachyura, Majoidea).

    Science.gov (United States)

    González-Pisani, Ximena; Gaspar Dellatorre, Fernando; López-Greco, Laura

    2013-01-01

    The embryonic development of the spider crabs Leurocyclus tuberculosus and Libinia spinosa was divided into five periods based on the differentiation of: (I) cleavage, (II) embryonic primordium, III) optic lobes, (IV) optic lobes pigmented and (V) chromatophores presence. Different traits such as spines, setae and telson morphology distinguish the two species from period III until hatching. Egg volume was greater in Leurocyclus tuberculosus than in Libinia spinosa. The duration of each period was different during development. Whereas in Leurocyclus tuberculosus period II (morphogenesis) is the longest, in Libinia spinosa the period IV is the longest. Complete embryonic development at 14'C lasted 36.7 +/- 3.1 days in Leurocyclus tuberculosus and 57.4 +/- 4.4 days in Libinia spinosa.

  9. Erythrophore cell response to food-associated pathogenic bacteria: implications for detection.

    Science.gov (United States)

    Hutchison, Janine R; Dukovcic, Stephanie R; Dierksen, Karen P; Carlyle, Calvin A; Caldwell, Bruce A; Trempy, Janine E

    2008-09-01

    Cell-based biosensors have been proposed for use as function-based detectors of toxic agents. We report the use of Betta splendens chromatophore cells, specifically erythrophore cells, for detection of food-associated pathogenic bacteria. Evaluation of erythrophore cell response, using Bacillus spp., has revealed that this response can distinguish pathogenic Bacillus cereus from a non-pathogenic B. cereus ΔplcR deletion mutant and a non-pathogenic Bacillus subtilis. Erythrophore cells were exposed to Salmonella enteritidis, Clostridium perfringens and Clostridium botulinum. Each bacterial pathogen elicited a response from erythrophore cells that was distinguished from the corresponding bacterial growth medium, and this observed response was unique for each bacterial pathogen. These findings suggest that erythrophore cell response has potential for use as a biosensor in the detection and toxicity assessment for food-associated pathogenic bacteria.

  10. Erythrophore cell response to food‐associated pathogenic bacteria: implications for detection

    Science.gov (United States)

    Hutchison, Janine R.; Dukovcic, Stephanie R.; Dierksen, Karen P.; Carlyle, Calvin A.; Caldwell, Bruce A.; Trempy, Janine E.

    2008-01-01

    Summary Cell‐based biosensors have been proposed for use as function‐based detectors of toxic agents. We report the use of Betta splendens chromatophore cells, specifically erythrophore cells, for detection of food‐associated pathogenic bacteria. Evaluation of erythrophore cell response, using Bacillus spp., has revealed that this response can distinguish pathogenic Bacillus cereus from a non‐pathogenic B. cereus ΔplcR deletion mutant and a non‐pathogenic Bacillus subtilis. Erythrophore cells were exposed to Salmonella enteritidis, Clostridium perfringens and Clostridium botulinum. Each bacterial pathogen elicited a response from erythrophore cells that was distinguished from the corresponding bacterial growth medium, and this observed response was unique for each bacterial pathogen. These findings suggest that erythrophore cell response has potential for use as a biosensor in the detection and toxicity assessment for food‐associated pathogenic bacteria. PMID:21261862

  11. Development of Betta splendens embryos and larvae reveals variation in pigmentation patterns.

    Science.gov (United States)

    Carey, Alexis N; Lyvers, Benjamin H; Ferrill, Rachel N; Johnson, Rachel L; Dumaine, Anne Marie; Sly, Belinda J

    2016-06-01

    Vertebrate pigmentation provides an ideal system for studying the intersections between evolution, genetics, and developmental biology. Teleost fish, with their accessible developmental stages and intense and diverse colours produced by chromatophores, are an ideal group for study. We set out to test whether Betta splendens is a good model organism for studying the evolution and development of diverse pigmentation. Our results demonstrate that B. splendens can be bred to produce large numbers of offspring with easily visualized pigment cells. Depending on the colour of the parents, there was variation in larval pigmentation patterns both within and between breeding events. In juveniles the developing adult pigmentation patterns showed even greater variation. These results suggest that B. splendens has great potential as a model organism for pigmentation studies.

  12. Bio-inspired artificial iriodphores based on capillary origami

    Science.gov (United States)

    Manakasettharn, Supone; Taylor, J. Ashley; Krupenkin, Tom

    2011-03-01

    Many marine organisms have evolved complex optical mechanisms of dynamic skin color control that allow them to drastically change their visual appearance. In particular, cephalopods have developed especially effective dynamic color control mechanism based on the mechanical actuation of the micro-scale optical structures, which produce either variable degrees of area coverage by a given color (chromatophores) or variations in spatial orientation of the reflective and diffractive surfaces (iridophores). In this work we describe bio-inspired artificial iridophores based on electrowetting-controlled capillary origami. We describe the developed microfabrication approach, characterize mechanical and optical properties of the obtained microstructures and discuss their electrowetting-based actuation. The obtained experimental results are in good agreement with a simple theoretical model based on electrocapillarity and elasticity theory. The results of the work can enable a broad range of novel optical devices.

  13. Individual colour patches as multicomponent signals.

    Science.gov (United States)

    Grether, Gregory F; Kolluru, Gita R; Nersissian, Karen

    2004-08-01

    Colour patches are complex traits, the components of which may evolve independently through a variety of mechanisms. Although usually treated as simple, two-dimensional characters and classified as either structural or pigmentary, in reality colour patches are complicated, three-dimensional structures that often contain multiple pigment types and structural features. The basic dermal chromatophore unit of fishes, reptiles and amphibians consists of three contiguous cell layers. Xanthophores and erythrophores in the outermost layer contain carotenoid and pteridine pigments that absorb short-wave light; iridophores in the middle layer contain crystalline platelets that reflect light back through the xanthophores; and melanophores in the basal layer contain melanins that absorb light across the spectrum. Changes in any one component of a chromatophore unit can drastically alter the reflectance spectrum produced, and for any given adaptive outcome (e.g. an increase in visibility), there may be multiple biochemical or cellular routes that evolution could take, allowing for divergent responses by different populations or species to similar selection regimes. All of the mechanisms of signal evolution that previously have been applied to single ornaments (including whole colour patches) could potentially be applied to the individual components of colour patches. To reach a complete understanding of colour patch evolution, however, it may be necessary to take an explicitly multi-trait approach. Here, we review multiple trait evolution theory and the basic mechanisms of colour production in fishes, reptiles and amphibians, and use a combination of computer simulations and empirical examples to show how multiple trait evolution theory can be applied to the components of single colour patches. This integrative perspective on animal colouration opens up a host of new questions and hypotheses. We offer specific, testable functional hypotheses for the most common pigmentary

  14. The Developmental Genetics of Vertebrate Color Pattern Formation: Lessons from Zebrafish.

    Science.gov (United States)

    Irion, Uwe; Singh, Ajeet Pratap; Nüsslein-Volhard, Christiane

    2016-01-01

    Color patterns are prominent features of many animals; they are highly variable and evolve rapidly leading to large diversities even within a single genus. As targets for natural as well as sexual selection, they are of high evolutionary significance. The zebrafish (Danio rerio) has become an important model organism for developmental biology and biomedical research in general, and it is the model organism to study color pattern formation in vertebrates. The fish display a conspicuous pattern of alternating blue and golden stripes on the body and on the anal and tail fins. This pattern is produced by three different types of pigment cells (chromatophores) arranged in precise layers in the hypodermis of the fish. In this essay, we will summarize the recent advances in understanding the developmental and genetic basis for stripe formation in the zebrafish. We will describe the cellular events leading to the formation of stripes during metamorphosis based on long-term lineage imaging. Mutant analysis has revealed that a number of signaling pathways are involved in the establishment and maintenance of the individual pigment cells. However, the striped pattern itself is generated by self-organizing mechanisms requiring interactions between all three pigment cell types. The involvement of integral membrane proteins, including connexins and potassium channels, suggests that direct physical contacts between chromatophores are involved, and that the directed transport of small molecules or bioelectrical coupling is important for these interactions. This mode of patterning by transmitting spatial information between adjacent tissues within three superimposed cell layers is unprecedented in other developmental systems. We propose that variations in the patterns among Danio species are caused by allelic differences in the genes responsible for these interactions.

  15. Light-Induced Infrared Difference Spectroscopy in the Investigation of Light Harvesting Complexes

    Directory of Open Access Journals (Sweden)

    Alberto Mezzetti

    2015-07-01

    Full Text Available Light-induced infrared difference spectroscopy (IR-DS has been used, especially in the last decade, to investigate early photophysics, energy transfer and photoprotection mechanisms in isolated and membrane-bound light harvesting complexes (LHCs. The technique has the definite advantage to give information on how the pigments and the other constituents of the biological system (proteins, membranes, etc. evolve during a given photoreaction. Different static and time-resolved approaches have been used. Compared to the application of IR-DS to photosynthetic Reaction Centers (RCs, however, IR-DS applied to LHCs is still in an almost pioneering age: very often sophisticated techniques (step-scan FTIR, ultrafast IR or data analysis strategies (global analysis, target analysis, multivariate curve resolution are needed. In addition, band assignment is usually more complicated than in RCs. The results obtained on the studied systems (chromatophores and RC-LHC supercomplexes from purple bacteria; Peridinin-Chlorophyll-a-Proteins from dinoflagellates; isolated LHCII from plants; thylakoids; Orange Carotenoid Protein from cyanobacteria are summarized. A description of the different IR-DS techniques used is also provided, and the most stimulating perspectives are also described. Especially if used synergically with other biophysical techniques, light-induced IR-DS represents an important tool in the investigation of photophysical/photochemical reactions in LHCs and LHC-containing systems.

  16. Chromogenic behaviors of the Humboldt squid (Dosidicus gigas) studied in situ with an animal-borne video package.

    Science.gov (United States)

    Rosen, Hannah; Gilly, William; Bell, Lauren; Abernathy, Kyler; Marshall, Greg

    2015-01-15

    Dosidicus gigas (Humboldt or jumbo flying squid) is an economically and ecologically influential species, yet little is known about its natural behaviors because of difficulties in studying this active predator in its oceanic environment. By using an animal-borne video package, National Geographic's Crittercam, we were able to observe natural behaviors in free-swimming D. gigas in the Gulf of California with a focus on color-generating (chromogenic) behaviors. We documented two dynamic displays without artificial lighting at depths of up to 70 m. One dynamic pattern, termed 'flashing' is characterized by a global oscillation (2-4 Hz) of body color between white and red. Flashing was almost always observed when other squid were visible in the video frame, and this behavior presumably represents intraspecific signaling. Amplitude and frequency of flashing can be modulated, and the phase relationship with another squid can also be rapidly altered. Another dynamic display termed 'flickering' was observed whenever flashing was not occurring. This behavior is characterized by irregular wave-like activity in neighboring patches of chromatophores, and the resulting patterns mimic reflections of down-welled light in the water column, suggesting that this behavior may provide a dynamic type of camouflage. Rapid and global pauses in flickering, often before a flashing episode, indicate that flickering is under inhibitory neural control. Although flashing and flickering have not been described in other squid, functional similarities are evident with other species.

  17. Mass spectrometric survey of peptides in cephalopods with an emphasis on the FMRFamide-related peptides.

    Science.gov (United States)

    Sweedler, J V; Li, L; Floyd, P; Gilly, W

    2000-12-01

    A matrix-assisted laser desorption/ionization (MALDI) mass spectrometric (MS) survey of the major peptides in the stellar, fin and pallial nerves and the posterior chromatophore lobe of the cephalopods Sepia officinalis, Loligo opalescens and Dosidicus gigas has been performed. Although a large number of putative peptides are distinct among the three species, several molecular masses are conserved. In addition to peptides, characterization of the lipid content of the nerves is reported, and these lipid peaks account for many of the lower molecular masses observed. One conserved set of peaks corresponds to the FMRFamide-related peptides (FRPs). The Loligo opalescens FMRFa gene has been sequenced. It encodes a 331 amino acid residue prohormone that is processed into 14 FRPs, which are both predicted by the nucleotide sequence and confirmed by MALDI MS. The FRPs predicted by this gene (FMRFa, FLRFa/FIRFa and ALSGDAFLRFa) are observed in all three species, indicating that members of this peptide family are highly conserved across cephalopods.

  18. Patterns of diatom treatment in two coexisting species of filter-feeding freshwater gastropods

    Directory of Open Access Journals (Sweden)

    Sitnikova T.Ya.

    2014-03-01

    Full Text Available To assess trophic partitioning among sympatric gastropod species in ancient lakes, we quantified diatoms in the guts of two coexistent Baikal gastropod species and tested for differences in species, size, and fracturing of large and small diatoms by taenioglossan radulae. In May 2010, the diatom Synedra acus dominated the littoral phytoplankton and gut contents of Baicalia turriformis and Teratobaikalia ciliata (Baicaliidae, both inhabiting the rocky Baikal littoral. In laboratory experiments, both ctenidial filter-feeding gastropods were fed with two diets of cultivated Synedra acus of different cell sizes: >150 μm and <100 μm. Field and laboratory studies revealed intact diatom cells (often with green chromatophores and fragmented frustules of diatoms <60 μm in the guts of both species. The two baicaliids varied in the number of ingested microalgae. In addition, they exhibited significantly different efficiencies for breaking large diatoms; B. turriformis broke large diatoms into more fragments than T. ciliata. The differences in the utilization of large and small diatoms by gastropods are discussed in terms of the relationships among coexisting species. Small diatom survival is considered from the view of interactions between producers and their consumers in the freshwater food web.

  19. Gene expression of a green fluorescent protein homolog as a host-specific biomarker of heat stress within a reef-building coral.

    Science.gov (United States)

    Smith-Keune, C; Dove, S

    2008-01-01

    Recent incidences of mass coral bleaching indicate that major reef building corals are increasingly suffering thermal stress associated with climate-related temperature increases. The development of pulse amplitude modulated (PAM) fluorometry has enabled rapid detection of the onset of thermal stress within coral algal symbionts, but sensitive biomarkers of thermal stress specific to the host coral have been slower to emerge. Differential display reverse transcription polymerase chain reaction (DDRT-PCR) was used to produce fingerprints of gene expression for the reef-building coral Acropora millepora exposed to 33 degrees C. Changes in the expression of 23 out of 399 putative genes occurred within 144 h. Down-regulation of one host-specific gene (AmA1a) occurred within just 6 h. Full-length sequencing revealed the product of this gene to be an all-protein chromatophore (green fluorescent protein [GFP]-homolog). RT-PCR revealed consistent down-regulation of this GFP-homolog for three replicate colonies within 6 h at both 32 degrees C and 33 degrees C but not at lower temperatures. Down-regulation of this host gene preceded significant decreases in the photosynthetic activity of photosystem II (dark-adapted F (v)/F (m)) of algal symbionts as measured by PAM fluorometry. Gene expression of host-specific genes such as GFP-homologs may therefore prove to be highly sensitive indicators for the onset of thermal stress within host coral cells.

  20. Ex-vivo cytotoxic, antibacterial and DPPH free radical scavenging assay with ethanolic leaf extract of Glycosmis pentaphylla to justify its traditional use

    Directory of Open Access Journals (Sweden)

    Prawej Ansari1,2

    2015-07-01

    Full Text Available Aim: Glycosmis pentaphylla belongs to the family Rutaceae. It is a shrub and locally common in the treatment of hepatic impairment. We have designed this study to provide a scientific basis with the traditional use of leaf of G. pentaphylla in the treatment of hepatitis.Methods: The well-established DPPH free radical scavenging activity was tested for antioxidant property evaluation. On the other hand, disk diffusion and brine shrimp method was respecti-velyused to determine antibacterial and cytotoxic activity. Results and Discussion: In the evaluation of antioxidant property IC50 found 204.91+/- 2.223 and micro;g/ml, in cytotoxicity testing, it is found that the plant part shows 30.49 +/- 1.976 and micro;g/ml of LC50. The ethanolic extract of G. pentaphylla leaves also have efficiency in bacterial growth inhibition; this extract is effective against for both gram, negative and positive. The zone of inhibition at 500 and micro;g/ml dose in E. coli and C. albican culture was 18 mm and 15 mm, respectively. In thin layer chromatography analysis, we found presence of couple of non-polar and polar component, presence of three non-chromatophoric component are also evident.Conclusion: Appropriate isolation and identification of mechanism is suggested in further study. [Biomed Res Ther 2015; 2(7.000: 324-332

  1. Squids old and young: Scale-free design for a simple billboard

    Science.gov (United States)

    Packard, Andrew

    2011-03-01

    Squids employ a large range of brightness-contrast spatial frequencies in their camouflage and signalling displays. The 'billboard' of coloured elements ('spots'=chromatophore organs) in the skin is built autopoietically-probably by lateral inhibitory processes-and enlarges as much as 10,000-fold during development. The resulting two-dimensional array is a fractal-like colour/size hierarchy lying in several layers of a multilayered network. Dynamic control of the array by muscles and nerves produces patterns that recall 'half-tone' processing (cf. ink-jet printer). In the more sophisticated (loliginid) squids, patterns also combine 'continuous tones' (cf. dye-sublimation printer). Physiologists and engineers can exploit the natural colour-coding of the integument to understand nerve and muscle system dynamics, examined here at the level of the ensemble. Integrative functions of the whole (H) are analysed in terms of the power spectrum within and between ensembles and of spontaneous waves travelling through the billboard. Video material may be obtained from the author at the above address.

  2. Cutaneous Chromatophoromas in Captive Snakes.

    Science.gov (United States)

    Muñoz-Gutiérrez, J F; Garner, M M; Kiupel, M

    2016-11-01

    Chromatophoromas are neoplasms arising from pigment-bearing cells (chromatophores) of the dermis. While isolated cases have been reported in the literature, the prevalence and biological behavior of chromatophoromas in snakes are unknown. Forty-two chromatophoromas were identified among 4663 submissions (0.9%) to a private diagnostic laboratory in a 16-year period. The most commonly affected snakes were colubrids (23 cases, 55%) and vipers (8 cases, 19%). The San Francisco garter snake was the most commonly affected species (6 cases; 14% of all affected snake species and 3.7% of all garter snake submissions). No sex predilection was found. The age of 28 snakes ranged from 5 to 27 years. Single cutaneous chromatophoromas were most commonly observed and presented as pigmented cutaneous masses or plaques along any body segment. Euthanasia or death due to progressive neoplastic disease or metastasis was reported in 8 (19%) and 4 (10%) cases, respectively. The survival time of 4 animals ranged from 4 to 36 months. Microscopically, xanthophoromas, iridophoromas, melanocytic neoplasms, and mixed chromatophoromas were identified, with melanocytic neoplasms being most common. Microscopic examination alone was generally sufficient for the diagnosis of chromatophoroma, but immunohistochemistry for S-100 and PNL-2 may be helpful for diagnosing poorly pigmented cases. Moderate to marked nuclear atypia appears to be consistently present in cutaneous chromatophoromas with a high risk of metastasis, while mitotic count, lymphatic invasion, the level of infiltration, and the degree of pigmentation or ulceration were not reliable predictors of metastasis.

  3. Induction Effect and Genetic Analysis of NG to Conchospores of Porphyra

    Institute of Scientific and Technical Information of China (English)

    Xu Pu; Shen Songdong; Fei Xiugeng; Zhang Xuecheng; Zhu Jianyi

    2002-01-01

    The new spreading conchospores ot Porphyra yezoensis, P. haitanensis and P. katadai var. hemiphylla are induced by N-Methy-N'-Nitro-N-Nitrosoguanidine (NG), a strong mutagen to induce the mutant of chromatophore. It is showed that (1) no mutants have been investigated in all control group. (2)The conchospores of all the three species of Porphyra are easy to be induced by NG for they are in the stage of breeding, In the lowest dose (10 μ g/mL) of this experiment, the mutant rate of P. yezoensis is up to 57.9%, that of P. haitanensis 30.7% and that of P. katadai var. hemiphylla 51.7%. (3)The mutant rate can not increase obviously by increasing the reagent concentration or prolonging the induction time. Within the scope of experiment, the inducement effects of three species of Porphyra ar e much similar, and the mutant rate is near 50%. The optimum induction concentration of NG is 10 μ g/mL, and the optimum induction time is 30 minutes.

  4. Induction Effect and Genetic Analysis of NG to Thallus of Porphyra

    Institute of Scientific and Technical Information of China (English)

    Xu Pu; Shen Songdong; Fei Xiugeng; Zhang Xuecheng; Zhu Jianyi

    2002-01-01

    The young thalli of Porphyra yezoensis and P. haitanensis are induced by N-Methy-N'-Nitro-N-Nitrosoguanidine (NG), a strong mutagen to induce the mutant of chromatophore. It is showed that no mutants have been investigated in all control groups,while in the induced groups, it is easy to find mutant cells or mutant cell masses in the thallus.The pigmentation mutants may be the result of NG inducement. The mutant rate increases obviously with the mutagen concentration or by prolonging the induction time. Within the scope of experiment, the inducement effects of Porphyra yezoensis are raised from 11.2% to 28.7%, and those of P. haitanensis from 10.1% to 20.2%. According to our experiments, the amount of mutant cells in the same area does not increase with the induction intensity The amount of mutant cells in every group of inducement of both species of Porphyra changes very little with the fixed fields check method. The lowest dose (25μg/mL) of this experiment has a high mutant rate. The mutant rate shows the percentage of mutant cells in all the survived cells, while the amount of mutant cells reflects the effect of inducement. Thus the optimum induction concentration of NG is 25μg/mL, and the optimum induction time is 30minutes.

  5. Xanthophore migration from the dermis to the epidermis and dermal remodeling during Salamandra salamandra salamandra (L.) larval development.

    Science.gov (United States)

    Pederzoli, Aurora; Gambarelli, Andrea; Restani, Cinzia

    2003-02-01

    During larval development of Salamandra salamandra salamandra chromatophores organize to form the definitive pigment pattern constituted by a black background with yellow patches that are characterized by epidermal xanthophores and dermal iridophores. Simultaneously the dermis undergoes remodeling from the larval stage to that typical of the adult. In the present study we ultrastucturally and immunocytochemically examined skin fragments of S. s. salamandra larvae and juveniles in order to investigate the modalities of xanthophore migration and differentiation in the context of dermal remodeling from the larval to adult stage. Semithin and thin sections showed that the dermis in newly born larvae consists of a compact connective tissue (basement lamella), to which fibroblasts and xanthophores adhere, and of a loose deep collagen layer. As larval development proceeds, fibroblasts and xanthophores invade the basement lamella, skin glands develop and the adult dermis forms. At metamorphosis, xanthophores reach the epidermis crossing through the basal lamina. We examined immunocytochemically the expression of signal molecules, such as fibronectin, vitronectin, beta1-integrin, chondroitin sulfate, E-cadherin, N-cadherin and plasminogen activator, which are known to be involved in regulating morphogenetic events. Their role in dermal remodeling and in pigment pattern formation is discussed.

  6. Reflector cells in the skin of Octopus dofleini.

    Science.gov (United States)

    Brocco, S L; Cloney, R A

    1980-01-01

    The cells that form the reflecting layer beneath the chromatophore organs of the octopus are conspicuous elements of its dermal chromatic system. Each flattened, ellipsoidal reflector cell in this layer bears thousands of peripherally radiating, discoidal, reflecting lamellae. Each lamella consists of a proteinaceous reflecting platelet enveloped by the plasmalemma. The lamellae average 90 nm in thickness and have variable diameters with a maximum of about 1.7 micrometer. Sets of reflecting lamellae are organized into functional units called reflectosomes. The lamellae in each reflectosome form a parallel array - similar to a stack of coins. The average number of lamellae in a reflectosome is 11. Adjacent lamellae are uniformly separated by an extracellular gap of about 60 nm in embedded specimens. The reflectosomes are randomly disposed over the surface of the reflector cell. The observed organization of the reflectosomes is compatible with its role as a quarter-wave thin-film interference device. The alternating reflecting lamellae and intelamellar spaces constitute layers of high and low refractive indices. Using measurements of the thicknesses and refractive indices of the platelets and interlamellar spaces, we have calculated that the color of reflected light should be blue - green, as seen in vivo. The sequence of events leading to the definitive arrangement of the reflectosomes is uncertain. The reflector cells of O. dofleini are compared and contrasted with the iridophores of squid.

  7. Elastic scattering spectroscopy in vivo: optical biopsies of cancers of the breast and GI tract

    Science.gov (United States)

    Pickard, David C. O.; Briggs, Gavin M.; Saunders, Christobel; Lakhani, Sunil; Ripley, Paul M.; Bigio, Irving J.; Bown, Stephen G.

    2000-04-01

    Elastic scattering or diffuse reflectance spectroscopy offers the possibility of distinguishing between normal and neoplastic tissue with a relatively simple optical measurement. The measurement of the reflection of light has previously been shown to be sensitive to the size and distribution of both intra and inter-cellular structures as well as absorption from chromatophores which are present in the tissue. By coupling a white light source and spectrometer to optic fibers it is possible to construct probes which can be inserted precutaneously or intra- operatively into breast tissue or which can pass down the channel of an endoscope and take in-vivo spectra of diseased and normal tissue in the Gastro-Intestinal tract. Spectra are reported from a large number of patients with a variety of benign, metaplastic, dysplastic and cancerous conditions. Some differences that have been observed in these spectra are discussed and the merits and disadvantages of 'optical biopsy' as an in-vivo diagnostic tool are examined. It is shown that to a relatively high degree of sensitivity and specificity it is possible to distinguish cancerous from normal tissue in a number of cases. The methods of distinguishing spectra and some possible modalities for their improvement are discussed.

  8. Cuttlefish use visual cues to control three-dimensional skin papillae for camouflage.

    Science.gov (United States)

    Allen, Justine J; Mäthger, Lydia M; Barbosa, Alexandra; Hanlon, Roger T

    2009-06-01

    Cephalopods (octopus, squid and cuttlefish) are known for their camouflage. Cuttlefish Sepia officinalis use chromatophores and light reflectors for color change, and papillae to change three-dimensional physical skin texture. Papillae vary in size, shape and coloration; nine distinct sets of papillae are described here. The objective was to determine whether cuttlefish use visual or tactile cues to control papillae expression. Cuttlefish were placed on natural substrates to evoke the three major camouflage body patterns: Uniform/Stipple, Mottle and Disruptive. Three versions of each substrate were presented: the actual substrate, the actual substrate covered with glass (removes tactile information) and a laminated photograph of the substrate (removes tactile and three-dimensional information because depth-of-field information is unavailable). No differences in Small dorsal papillae or Major lateral mantle papillae expression were observed among the three versions of each substrate. Thus, visual (not tactile) cues drive the expression of papillae in S. officinalis. Two sets of papillae (Major lateral mantle papillae and Major lateral eye papillae) showed irregular responses; their control requires future investigation. Finally, more Small dorsal papillae were shown in Uniform/Stipple and Mottle patterns than in Disruptive patterns, which may provide clues regarding the visual mechanisms of background matching versus disruptive coloration.

  9. Do cephalopods communicate using polarized light reflections from their skin?

    Science.gov (United States)

    Mäthger, Lydia M; Shashar, Nadav; Hanlon, Roger T

    2009-07-01

    Cephalopods (squid, cuttlefish and octopus) are probably best known for their ability to change color and pattern for camouflage and communication. This is made possible by their complex skin, which contains pigmented chromatophore organs and structural light reflectors (iridophores and leucophores). Iridophores create colorful and linearly polarized reflective patterns. Equally interesting, the photoreceptors of cephalopod eyes are arranged in a way to give these animals the ability to detect the linear polarization of incoming light. The capacity to detect polarized light may have a variety of functions, such as prey detection, navigation, orientation and contrast enhancement. Because the skin of cephalopods can produce polarized reflective patterns, it has been postulated that cephalopods could communicate intraspecifically through this visual system. The term 'hidden' or 'private' communication channel has been given to this concept because many cephalopod predators may not be able to see their polarized reflective patterns. We review the evidence for polarization vision as well as polarization signaling in some cephalopod species and provide examples that tend to support the notion--currently unproven--that some cephalopods communicate using polarized light signals.

  10. Electrowetting-controlled bio-inspired artificial iridophores

    Science.gov (United States)

    Manakasettharn, Supone; Taylor, J. Ashley; Krupenkin, Tom

    2011-10-01

    Many marine organisms have evolved complex optical mechanisms of dynamic skin color control that allow them to drastically change their visual appearance. In particular, cephalopods have developed especially effective dynamic color control mechanism based on the mechanical actuation of the micro-scale optical structures, which produce either variable degrees of area coverage by a given color (chromatophores) or variations in spatial orientation of the reflective and diffractive surfaces (iridophores). In this work we describe the design, fabrication and characterization of electrowetting-controlled bio-inspired artificial iridophores. The developed iridophores geometrically resemble microflowers with flexible reflective petals. The microflowers are fabricated on a silicon substrate using surface micromachining techniques. After fabrication a small droplet of conductive liquid is deposited at the center of each microflower. This causes the flower petals to partially wrap around the droplet forming a structure similar to capillary origami. The dynamic control over the degree of wrapping is achieved by applying a voltage differential between the conductive core of the petals and the droplet. The applied voltage causes dynamic contact angle change between the droplet and each of the petals due to the electrowetting effect. We have characterized mechanical and optical properties of the microstructures and discuss their electrowetting-based actuation. These experimental results are in good agreement with a 3D theoretical model based on electrocapillarity and elasticity theory. This work forms the basis for a broad range of novel optical devices.

  11. Application of the Accurate Mass and Time Tag Approach to the Proteome Analysis of Sub-cellular Fractions Obtained from Rhodobacter sphaeroides 2.4.1 Aerobic and Photosynthetic Cell Cultures

    Energy Technology Data Exchange (ETDEWEB)

    Callister, Stephen J.; Dominguez, Migual; Nicora, Carrie D.; Zeng, Xiaohua; Tavano, Christine; Kaplan, Samuel; Donohue, Timothy; Smith, Richard D.; Lipton, Mary S.

    2006-08-04

    Abstract The high-throughput accurate mass and time tag (AMT) proteomic approach was utilized to characterize the proteomes for cytoplasm, cytoplasmic membrane, periplasm, and outer membrane fractions from aerobic and photosynthetic cultures of the gram-nagtive bacterium Rhodobacter sphaeroides 2.4.1. In addition, we analyzed the proteins within purified chromatophore fractions that house the photosynthetic apparatus from photosynthetically grown cells. In total, 8300 peptides were identified with high confidence from at least one sub-cellular fraction from either cell culture. These peptides were derived from 1514 genes or 35% percent of proteins predicted to be encoded by the genome. A significant number of these proteins were detected within a single sub-cellular fraction and their localization was compared to in-silico predictions. However, the majority of proteins were observed in multiple sub-cellular fractions, and the most likely sub-cellular localization for these proteins was investigated using a Z-score analysis of peptide abundance along with clustering techniques. Good (81%) agreement was observed between the experimental results and in-silico predictions. The AMT tag approach provides localization evidence for those proteins that have no predicted localization information, those annotated as putative proteins, and/or for those proteins annotated as hypothetical and conserved hypothetical.

  12. A Novel Biosensor to Detect MicroRNAs Rapidly

    Directory of Open Access Journals (Sweden)

    Jie-Ying Liao

    2009-01-01

    Full Text Available δ-free F0F1-ATPase within chromatophore was constructed as a novel biosensor to detect miRNA targets. Specific miRNA probes were linked to each rotary β subunits of F0F1-ATPase. Detection of miRNAs was based on the proton flux change induced by light-driven rotation of δ-free F0F1-ATPase. The hybridization reaction was indicated by changes in the fluorescent intensity of pH-sensitive CdTe quantum dots. Our results showed that the assay was attomole sensitivities (1.2×10−18 mol to target miRNAs and capable of distinguishing among miRNA family members. Moreover, the method could be used to monitor real-time hybridization without any complicated fabrication before hybridization. Thus, the rotary biosensor is not only sensitive and specific to detect miRNA target but also easy to perform. The δ-free F0F1-ATPase-based rotary biosensor may be a promising tool for the basic research and clinical application of miRNAs.

  13. Transparent crucian carp Carassius auratus, a fish model suitable for study in vivo%透明鲫——一个适合活体研究的鱼类模型

    Institute of Scientific and Technical Information of China (English)

    李凯彬; 汪学杰; 常藕琴; 刘春; 王芳; 马必勇; 梁慧丽; 吴淑勤

    2011-01-01

    目的 了解鲫成体透明的原因,探讨该性状的应用特性,为透明鲫作为水生实验动物材料系统开发提供基础.方法 对透明鲫进行繁殖,并观察其后代性状,了解透明性状的遗传规律;体视镜观察透明鲫色素细胞的种类与分布,并与鲫比较;组织切片和压片确认微孢子虫对透明鲫的感染,并观察感染症状的变化.结果 鲫的透明性状可以遗传,大部分后代表现为通体透明,心、肝、肾、肠、鳔、鳃、脊椎等组织器官肉眼清晰可见.与正常鲫比较,透明鲫的主要色素细胞为黄色素细胞,并未发现虹彩色素细胞,黑色素细胞的数量也大为减少.微孢子虫对鱼体的感染过程可直观观察,病原的扩散和空间分布能实时获得,具普通鱼类无法比拟的应用优势.结论 虹彩色素细胞的缺失是鲫透明突变的结构基础.由于透明鲫内部器官可直接观测,无需依靠解剖或复杂仪器系统,在同一动物身上可能获得一系列的动态试验数据,或可作为模型材料广泛应用于生命科学不同领域.%Objective To better understand the mechanism of transparency in adult crucian carp, explore its application and provide more evidence to support it as a novel aquatic animal model. Methods The transparent crucian carp was bred,and the phenotype of offsprings was examined to learn the inheritance of the transparent character. A stereo-microscope was used to examine the types and patterns of chromatophores in transparent and common crucian carps. The fish infected with microsporidia were closely monitored. Tissue sections and wet-mounted squashes were prepared to observe the parasites in muscle tissues, and tissue sections were used to characterize the pathological changes under the light microscope. Results The transparent fish were healthy and fertile, showing a inherent character. The mutants manifested as entire transparent body. The main internal organs, such as heart, liver

  14. Femtosecond and hole-burning studies of B800`s excitation energy relaxation dynamics in the LH2 antenna complex of Rhodopseudomonas acidophila (strain 10050)

    Energy Technology Data Exchange (ETDEWEB)

    Wu, H.M.; Savikhin, S.; Reddy, N.R.S.; Jankowiak, R.; Struve, W.S.; Small, G.J. [Ames Lab., IA (United States)]|[Iowa State Univ., Ames, IA (United States); Cogdell, R.J. [Univ. of Glasgow (United Kingdom)

    1996-07-18

    One- and two-color pump/probe femtosecond and hole-burning data are reported for the isolated B800-850 (LH2) antenna complex of Rhodopseudomonas acidophila (strain 10050). The two-color profiles are interpretable in terms of essentially monophasic B800{yields}B850 energy transfer with kinetics ranging from 1.6 to 1.1 ps between 19 and 130 K for excitation at or to the red of the B800 absorption maximum. The B800 zero-phonon hole profiles obtained at 4.2 K with burn frequencies located near or to the red of this maximum yielded a transfer time of 1.8 ps. B800 hole-burning data (4.2 K) are also reported for chromatophores at ambient pressure and pressures of 270 and 375 MPa. At ambient pressure the B800-B850 energy gap is 950 cm{sup -1}, while at 270 and 375 MPa it is close to 1000 and 1050 cm{sup -1}, respectively. However, no dependence of the B800{yields}B850 transfer time on pressure was observed. The resilience of the transfer rate to pressure-induced changes in the energy gap and the weak temperature dependence of the rate are consistent with the model that has the spectral overlap (of Foerster theory) provided by the B800 fluorescence origin band and weak vibronic absorption bands of B850. However, both the time domain and hole-burning data establish that there is an additional relaxation channel for B800, which is observed when excitation is located to the blue of the B800 absorption maximum. 40 refs., 11 figs., 6 tabs.

  15. Progress in Systematics of Audouinella Bory%奥杜藻属Audouinella系统分类研究进展

    Institute of Scientific and Technical Information of China (English)

    韩晓静; 冯佳; 谢树莲

    2011-01-01

    奥杜藻属(Audouinella)是淡水红藻中一个比较重要的类群,主要特征是:藻体为单列细胞组成的分枝丝体,细胞具数个周生盘状色素体,有时边缘浅裂,无蛋白核.可产生单孢子囊进行无性生殖,具有有性生殖过程.已知的种类全部为淡水产.中国淡水奥杜藻属已报道的种类有10种2变种.利用分子生物学手段对我国淡水奥杜藻属进行深入系统的、多特征的分类研究,将是今后研究的主要发展方向.%Audouinella Boxy is quite a important group of freshwater red algae. Currently ,the main features of the genus are considered:the thalli are branched and consisted of single row of cells;a few chromatophores are discoid and parietal ,sometimes margin lobed ,pyrenoid absent ;asexual reproduction is by monospores and sexual reproduction is occured. A11 of known species live in freshwater. The genus is belonged to Acrochaetiaceae, Acrochaetiales. The complete life cycle of Audouinella includes three homomorphons plants, isogamete, tetrasporophyte and filament of asexual reproduction by monospores. Ten species and two varieties of freshwater Audouinella Bory are recorded in China. But the sexual reproduction has not been described. It will be focused on the systematics based on multi-characteristics for freshwater Audouinella Bory using molecular biological data. Furthermore,the phylogenetics will be reaearehed and the molecular phylogenetie tree will be constraeted about Audouinella Bory in China.

  16. Ethogram analysis reveals new body patterning behavior of the tropical arrow squid Doryteuthis plei off the São Paulo Coast.

    Science.gov (United States)

    Postuma, Felippe A; Gasalla, Maria A

    2015-10-01

    Squids can express several body patterns, aided by a variety of visual signals that are produced by chromatophore organs. However, for several squid species, body patterning behavior during reproductive activity is still not completely understood. For example, what are the specific patterning changes and other visual signals, how do they appear, and how long do they last? To test the hypothesis that distinct chromatic components appear at different durations on the skin of the tropical arrow squid Doryteuthis plei in the Southern Hemisphere, we identified and described its body patterning behavior. Specimen squids were obtained from off the South Brazil Bight, near the coast of the São Paulo shelf. Animals were maintained and monitored in circular tanks for 62 d over six observation periods, from 2011 through 2013. An ethogram was constructed showing 19 chromatic, 5 locomotor, and 12 postural components, or body patterns, associated with reproductive behavior. New chromatic components (i.e., those not yet reported in the North Atlantic D. plei species), particularly those linked to female sexual maturity, were observed. A postural component, the "J-Posture," linked to defenses and alarm, also was noted. The average time spent for "light" components was 32 s. The corresponding "dark" components had an average duration of 28 s. Females displayed the chromatic components related to calm behavior longer than males. However, males appeared to be more dedicated to disputes over resources, and used rapid, miscellaneous visual signaling. In conclusion, new basic types of body patterns are described for D. plei. The repertoire of chromatic components reported in the ethogram is, to our knowledge, the first record for D. plei of the Southern Hemisphere.

  17. An ethogram of body patterning behavior in the biomedically and commercially valuable squid Loligo pealei off Cape Cod, Massachusetts.

    Science.gov (United States)

    Hanlon, R T; Maxwell, M R; Shashar, N; Loew, E R; Boyle, K L

    1999-08-01

    Squids have a wide repertoire of body patterns; these patterns contain visual signals assembled from a highly diverse inventory of chromatic, postural, and locomotor components. The chromatic components reflect the activity of dermal chromatophore organs that, like the postural and locomotor muscles, are controlled directly from the central nervous system. Because a thorough knowledge of body patterns is fundamental to an understanding of squid behavior, we have compiled and described an ethogram (a catalog of body patterns and associated behaviors) for Loligo pealei. Observations of this species were made over a period of three years (> or = 440 h) and under a variety of behavioral circumstances. The natural behavior of the squid was filmed on spawning grounds off Cape Cod (northwestern Atlantic), and behavioral trials in the laboratory were run in large tanks. The body pattern components--34 chromatic (including 4 polarization components), 5 postural, and 12 locomotor--are each described in detail. Eleven of the most common body patterns are also described. Four of them are chronic, or long-lasting, patterns for crypsis; an example is Banded Bottom Sitting, which produces disruptive coloration against the substrate. The remaining seven patterns are acute; they are mostly used in intraspecific communication among spawning squids. Two of these acute patterns--Lateral Display and Mate Guarding Pattern--are used during agonistic bouts and mate guarding; they are visually bright and conspicuous, which may subject the squids to predation; but we hypothesize that schooling and diurnal activity may offset the disadvantage presented by increased visibility to predators. The rapid changeability and the diversity of body patterns used for crypsis and communication are discussed in the context of the behavioral ecology of this species.

  18. Field and experimental evidence of Vibrio parahaemolyticus as the causative agent of acute hepatopancreatic necrosis disease of cultured shrimp (Litopenaeus vannamei) in Northwestern Mexico.

    Science.gov (United States)

    Soto-Rodriguez, Sonia A; Gomez-Gil, Bruno; Lozano-Olvera, Rodolfo; Betancourt-Lozano, Miguel; Morales-Covarrubias, Maria Soledad

    2015-03-01

    Moribund shrimp affected by acute hepatopancreatic necrosis disease (AHPND) from farms in northwestern Mexico were sampled for bacteriological and histological analysis. Bacterial isolates were molecularly identified as Vibrio parahaemolyticus by the presence of the tlh gene. The tdh-negative, trh-negative, and tlh-positive V. parahaemolyticus strains were further characterized by repetitive extragenic palindromic element-PCR (rep-PCR), and primers AP1, AP2, AP3, and AP and an ems2 IQ2000 detection kit (GeneReach, Taiwan) were used in the diagnostic tests for AHPND. The V. parahaemolyticus strains were used in immersion challenges with shrimp, and farmed and challenged shrimp presented the same clinical and pathological symptoms: lethargy, empty gut, pale and aqueous hepatopancreas, and expanded chromatophores. Using histological analysis and bacterial density count, three stages of AHNPD (initial, acute, and terminal) were identified in the affected shrimp. The pathognomonic lesions indicating severe desquamation of tubular epithelial cells of the hepatopancreas were observed in both challenged and pond-infected shrimp. The results showed that different V. parahaemolyticus strains have different virulences; some of the less virulent strains do not induce 100% mortality, and mortality rates also rise more slowly than they do for the more virulent strains. The virulence of V. parahaemolyticus strains was dose dependent, where the threshold infective density was 10(4) CFU ml(-1); below that density, no mortality was observed. The AP3 primer set had the best sensitivity and specificity. Field and experimental results showed that the V. parahaemolyticus strain that causes AHPND acts as a primary pathogen for shrimp in Mexico compared with the V. parahaemolyticus strains reported to date.

  19. Zebrafish Zic2a and Zic2b regulate neural crest and craniofacial development.

    Science.gov (United States)

    Teslaa, Jessica J; Keller, Abigail N; Nyholm, Molly K; Grinblat, Yevgenya

    2013-08-01

    Holoprosencephaly (HPE), the most common malformation of the human forebrain, is associated with defects of the craniofacial skeleton. ZIC2, a zinc-finger transcription factor, is strongly linked to HPE and to a characteristic set of dysmorphic facial features in humans. We have previously identified important functions for zebrafish Zic2 in the developing forebrain. Here, we demonstrate that ZIC2 orthologs zic2a and zic2b also regulate the forming zebrafish craniofacial skeleton, including the jaw and neurocranial cartilages, and use the zebrafish to study Zic2-regulated processes that may contribute to the complex etiology of HPE. Using temporally controlled Zic2a overexpression, we show that the developing craniofacial cartilages are sensitive to Zic2 elevation prior to 24hpf. This window of sensitivity overlaps the critical expansion and migration of the neural crest (NC) cells, which migrate from the developing neural tube to populate vertebrate craniofacial structures. We demonstrate that zic2b influences the induction of NC at the neural plate border, while both zic2a and zic2b regulate NC migratory onset and strongly contribute to chromatophore development. Both Zic2 depletion and early ectopic Zic2 expression cause moderate, incompletely penetrant mispatterning of the NC-derived jaw precursors at 24hpf, yet by 2dpf these changes in Zic2 expression result in profoundly mispatterned chondrogenic condensations. We attribute this discrepancy to an additional role for Zic2a and Zic2b in patterning the forebrain primordium, an important signaling source during craniofacial development. This hypothesis is supported by evidence that transplanted Zic2-deficient cells can contribute to craniofacial cartilages in a wild-type background. Collectively, these data suggest that zebrafish Zic2 plays a dual role during craniofacial development, contributing to two disparate aspects of craniofacial morphogenesis: (1) neural crest induction and migration, and (2) early

  20. Dose-dependent effects of the clinical anesthetic isoflurane on Octopus vulgaris: a contribution to cephalopod welfare.

    Science.gov (United States)

    Polese, Gianluca; Winlow, William; Di Cosmo, Anna

    2014-12-01

    Recent progress in animal welfare legislation relating to invertebrates has provoked interest in methods for the anesthesia of cephalopods, for which different approaches to anesthesia have been tried but in most cases without truly anesthetizing the animals. For example, several workers have used muscle relaxants or hypothermia as forms of "anesthesia." Several inhalational anesthetics are known to act in a dose-dependent manner on the great pond snail Lymnaea stagnalis, a pulmonate mollusk. Here we report, for the first time, on the effects of clinical doses of the well-known inhalational clinical anesthetic isoflurane on the behavioral responses of the common octopus Octopus vulgaris. In each experiment, isoflurane was equilibrated into a well-aerated seawater bath containing a single adult O. vulgaris. Using a web camera, we recorded each animal's response to touch stimuli eliciting withdrawal of the arms and siphon and observed changes in the respiratory rate and the chromatophore pattern over time (before, during, and after application of the anesthetic). We found that different animals of the same size responded with similar behavioral changes as the isoflurane concentration was gradually increased. After gradual application of 2% isoflurane for a maximum of 5 min (at which time all the responses indicated deep anesthesia), the animals recovered within 45-60 min in fresh aerated seawater. Based on previous findings in gastropods, we believe that the process of anesthesia induced by isoflurane is similar to that previously observed in Lymnaea. In this study we showed that isoflurane is a good, reversible anesthetic for O. vulgaris, and we developed a method for its use.

  1. A redescription of morphologically similar species from the genus Euglena: E. laciniata, E. sanguinea, E. sociabilis, and E. splendens(1).

    Science.gov (United States)

    Karnkowska-Ishikawa, Anna; Milanowski, Rafał; Triemer, Richard E; Zakryś, Bożena

    2013-06-01

    Euglena sanguinea (Ehrenberg 1831) was one of the first green euglenoid species described in the literature. At first, the species aroused the interest of researchers mainly due to the blood-red color of its cells, which, as it later turned out, is not a constant feature. Complicated chloroplast morphology, labeled by Pringsheim as the "peculiar chromatophore system", made the correct identification of the species difficult, which is the reason why, throughout the 20th century, new species resembling E. sanguinea were continually being named due to a lack of suitable diagnostic features to distinguish E. sanguinea. Interest in E. sanguinea has returned in recent years, following findings that the species can produce ichthyotoxins. This was followed by the need to classify E. sanguinea correctly, which was achieved through the verification of morphological and molecular data for all species similar to E. sanguinea. As the result of the analysis, the number of species sharing some morphological similarities with E. sanguinea could be reduced from 12, as described in the literature, to four, with established epitypes and updated diagnostic descriptions. The most important diagnostic features included: the presence of mucocysts (i.e., whether they were visible before and/or after staining), the number of chloroplasts, the size of the double-sheathed pyrenoids, and the presence of the large paramylon grain in the vicinity of the stigma. Moreover, sequence analysis revealed the presence of unusually long SSU rDNA sequences in E. sanguinea. Previously, SSU rDNA sequences of such length were known to be present in primary osmotrophic euglenoids.

  2. Transient ectopic overexpression of agouti-signalling protein 1 (asip1 induces pigment anomalies in flatfish.

    Directory of Open Access Journals (Sweden)

    Raúl Guillot

    Full Text Available While flatfish in the wild exhibit a pronounced countershading of the dorso-ventral pigment pattern, malpigmentation is commonly observed in reared animals. In fish, the dorso-ventral pigment polarity is achieved because a melanization inhibition factor (MIF inhibits melanoblast differentiation and encourages iridophore proliferation in the ventrum. A previous work of our group suggested that asip1 is the uncharacterized MIF concerned. In order to further support this hypothesis, we have characterized asip1 mRNAs in both turbot and sole and used deduced peptide alignments to analyze the evolutionary history of the agouti-family of peptides. The putative asip precursors have the characteristics of a secreted protein, displaying a putative hydrophobic signal. Processing of the potential signal peptide produces mature proteins that include an N-terminal region, a basic central domain with a high proportion of lysine residues as well as a proline-rich region that immediately precedes the C-terminal poly-cysteine domain. The expression of asip1 mRNA in the ventral area was significantly higher than in the dorsal region. Similarly, the expression of asip1 within the unpigmented patches in the dorsal skin of pseudoalbino fish was higher than in the pigmented dorsal regions but similar to those levels observed in the ventral skin. In addition, the injection/electroporation of asip1 capped mRNA in both species induced long term dorsal skin paling, suggesting the inhibition of the melanogenic pathways. The data suggest that fish asip1 is involved in the dorsal-ventral pigment patterning in adult fish, where it induces the regulatory asymmetry involved in precursor differentiation into mature chromatophore. Adult dorsal pseudoalbinism seems to be the consequence of the expression of normal developmental pathways in an inaccurate position that results in unbalanced asip1 production levels. This, in turn, generates a ventral-like differentiation environment

  3. BIO-ORGANIC CHEMISTRY QUARTERLY REPORT. June through August1963

    Energy Technology Data Exchange (ETDEWEB)

    Various

    1963-10-02

    This report covers the following titles: (1) The Effects of 8-Methyl Lipoic Acid on the Evolution of Oxygen and Reduction of Carbon Dioxide during Photosynthesis; (2) Further {sup 14}C and {sup 15}N Tracer Studies of Amino Acid Synthesis during Photosynthesis by Chlorella Pyrenoidosa; (3) Two-Dimensional High Voltage, Low-Temperature Paper Electrophoresis of {sup 14}C-Labeled Products of Photosynthesis with {sup 14}CO{sub 2}; (4) A Search for Enzymic and Nonenzymic Reactions Between Thiamine Derivatives and Sugar Phosphates; (5) The Cytochrome Content of Purified Spinach Chloroplast Lamellae; (6) The Osmium Tetroxide Fixation of Chloroplast Lamellae; (7) Kinetics of Exoenzymes and Applications to the Determination of the Sequence of Nucleic Acids; (8) Brain Biochemistry and Behavior in Rats; (9) Experiments on Classical Conditioning and Light Habituation in Planarians; (10) Operant Conditioning in Planarians; (11) Manganese Porphyrin Complexes; (12) EPR Studies of Some Complex Organic Solutions; (13) Transient Response of Light-induced Photosynthetic Electron Paramagnetic Resonance Signals: Rhodospirillum rubrum Chromatophores; (14) Studies of the Tautomerism of Amides; (15) Structure and Mechanism of Hydrolysis of the Product of Reaction of PZ05 and Ethyl Ether; (16) A Study of the Irradiation Products of Several Nitrones; (17) Biosynthesis of the Opium Alkaloids; (18) Synthesis of methyl-{beta}-D-thiogalactoside-{sup 35}S; (19) Effect of Acridine Orange and Visible Light on Thymine Dimer Formation and Disruption; (20) Some Aspects of the Radiation Chemistry of DNA; (21) Nuclear Magnetic Resonance; and (22) Studies on the Inhibition of the Photoreduction of FMN.

  4. Effect of changes in the composition of cellular fatty acids on membrane fluidity of Rhodobacter sphaeroides.

    Science.gov (United States)

    Kim, Eui-Jin; Lee, Jeong K

    2015-02-01

    The cellular fatty acid composition is important for metabolic plasticity in Rhodobacter sphaeroides. We explored the effects of changing the cellular ratio of unsaturated fatty acids (UFAs) to saturated fatty acids (SFAs) in R. sphaeroides by overexpressing several key fatty acid biosynthetic enzymes through the use of expression plasmid pRK415. Bacteria containing the plasmid pRKfabI1 with the fabI1 gene that encodes enoyl-acyl carrier protein (ACP) reductase showed a reduction in the cellular UFA to SFA ratio from 4 (80% UFA) to 2 (65% UFA) and had decreased membrane fluidity and reduced cell growth. Additionally, the ratio of UFA to SFA of the chromatophore vesicles from pRKfabI1 -containing cells was similarly lowered, and the cell had decreased levels of light-harvesting complexes, but no change in intracytoplasmic membrane (ICM) content or photosynthetic (PS) gene expression. Both inhibition of enoyl- ACP reductase with diazaborine and addition of exogenous UFA restored membrane fluidity, cell growth, and the UFA to SFA ratio to wild-type levels in this strain. R. sphaeroides containing the pRKfabB plasmid with the fabB gene that encodes the enzyme β-ketoacyl-ACP synthase I exhibited an increased UFA to SFA ratio from 4 (80% UFA) to 9 (90% UFA), but showed no change in membrane fluidity or growth rate relative to control cells. Thus, membrane fluidity in R. sphaeroides remains fairly unchanged when membrane UFA levels are between 80% and 90%, whereas membrane fluidity, cell growth, and cellular composition are affected when UFA levels are below 80%.

  5. A single origin of the photosynthetic organelle in different Paulinella lineages

    Directory of Open Access Journals (Sweden)

    Ishida Ken-ichiro

    2009-05-01

    Full Text Available Abstract Background Gaining the ability to photosynthesize was a key event in eukaryotic evolution because algae and plants form the base of the food chain on our planet. The eukaryotic machines of photosynthesis are plastids (e.g., chloroplast in plants that evolved from cyanobacteria through primary endosymbiosis. Our knowledge of plastid evolution, however, remains limited because the primary endosymbiosis occurred more than a billion years ago. In this context, the thecate "green amoeba" Paulinella chromatophora is remarkable because it very recently (i.e., minimum age of ≈ 60 million years ago acquired a photosynthetic organelle (termed a "chromatophore"; i.e., plastid via an independent primary endosymbiosis involving a Prochlorococcus or Synechococcus-like cyanobacterium. All data regarding P. chromatophora stem from a single isolate from Germany (strain M0880/a. Here we brought into culture a novel photosynthetic Paulinella strain (FK01 and generated molecular sequence data from these cells and from four different cell samples, all isolated from freshwater habitats in Japan. Our study had two aims. The first was to compare and contrast cell ultrastructure of the M0880/a and FK01 strains using scanning electron microscopy. The second was to assess the phylogenetic diversity of photosynthetic Paulinella to test the hypothesis they share a vertically inherited plastid that originated in their common ancestor. Results Comparative morphological analyses show that Paulinella FK01 cells are smaller than M0880/a and differ with respect to the number of scales per column. There are more distinctive, multiple fine pores on the external surface of FK01 than in M0880/a. Molecular phylogenetic analyses using multiple gene markers demonstrate these strains are genetically distinct and likely comprise separate species. The well-supported monophyly of the Paulinella chromatophora strains analyzed here using plastid-encoded 16S rRNA suggests strongly

  6. Focus on membrane differentiation and membrane domains in the prokaryotic cell.

    Science.gov (United States)

    Boekema, Egbert J; Scheffers, Dirk-Jan; van Bezouwen, Laura S; Bolhuis, Henk; Folea, I Mihaela

    2013-01-01

    A summary is presented of membrane differentiation in the prokaryotic cell, with an emphasis on the organization of proteins in the plasma/cell membrane. Many species belonging to the Eubacteria and Archaea have special membrane domains and/or membrane proliferation, which are vital for different cellular processes. Typical membrane domains are found in bacteria where a specific membrane protein is abundantly expressed. Lipid rafts form another example. Despite the rareness of conventional organelles as found in eukaryotes, some bacteria are known to have an intricate internal cell membrane organization. Membrane proliferation can be divided into curvature and invaginations which can lead to internal compartmentalization. This study discusses some of the clearest examples of bacteria with such domains and internal membranes. The need for membrane specialization is highest among the heterogeneous group of bacteria which harvest light energy, such as photosynthetic bacteria and halophilic archaea. Most of the highly specialized membranes and domains, such as the purple membrane, chromatophore and chlorosome, are found in these autotrophic organisms. Otherwise the need for membrane differentiation is lower and variable, except for those structures involved in cell division. Microscopy techniques have given essential insight into bacterial membrane morphology. As microscopy will further contribute to the unraveling of membrane organization in the years to come, past and present technology in electron microscopy and light microscopy is discussed. Electron microscopy was the first to unravel bacterial morphology because it can directly visualize membranes with inserted proteins, which no other technique can do. Electron microscopy techniques developed in the 1950s and perfected in the following decades involve the thin sectioning and freeze fractioning of cells. Several studies from the golden age of these techniques show amazing examples of cell membrane morphology

  7. Light-harvesting complex 1 stabilizes P+QB- charge separation in reaction centers of Rhodobacter sphaeroides.

    Science.gov (United States)

    Francia, Francesco; Dezi, Manuela; Rebecchi, Alberto; Mallardi, Antonia; Palazzo, Gerardo; Melandri, Bruno Andrea; Venturoli, Giovanni

    2004-11-09

    The kinetics of charge recombination following photoexcitation by a laser pulse have been analyzed in the reaction center-light harvesting complex 1 (RC-LH1) purified from the photosynthetic bacterium Rhodobacter sphaeroides. In RC-LH1 core complexes isolated from photosynthetically grown cells P(+)Q(B)(-) recombines with an average rate constant, k approximately 0.3 s(-1), more than three times smaller than that measured in RC deprived of the LH1 (k approximately 1 s(-1)). A comparable, slowed recombination kinetics is observed in RC-LH1 complexes purified from a pufX-deleted strain. Slowing of the charge recombination kinetics is even more pronounced in RC-LH1 complexes isolated from wild-type semiaerobically grown cells (k approximately 0.2 s(-1)). Since the kinetics of P(+)Q(A)(-) recombination is unaffected by the presence of the antenna, the P(+)Q(B)(-) state appears to be energetically stabilized in core complexes. Determinations of the ubiquinone-10 (UQ(10)) complement associated with the purified RC-LH1 complexes always yield UQ(10)/RC ratios larger than 10. These quinone molecules are functionally coupled to the RC-LH1 complex, as judged from the extent of exogenous cytochrome c(2) rapidly oxidized under continuous light excitation. Analysis of P(+)Q(B)(-) recombination, based on a kinetic model which considers fast quinone equilibrium at the Q(B) binding site, indicates that the slowing down of charge recombination kinetics observed in RC-LH1 complexes cannot be explained solely by a quinone concentration effect and suggests that stabilization of the light-induced charge separation is predominantly due to interaction of the Q(B) site with the LH1 complex. The high UQ(10) complements detected in RC-LH1 core complexes, but not in purified light-harvesting complex 2 and in RC, are proposed to reflect an in vivo heterogeneity in the distribution of the quinone pool within the chromatophore bilayer.

  8. Effects of environmental and artificial UV-B radiation on freshwater prawn Macrobrachium olfersi embryos

    Energy Technology Data Exchange (ETDEWEB)

    Nazari, Evelise Maria [Programa de Pos-Graduacao em Ciencias Morfologicas, Instituto de Ciencias Biomedicas, Universidade Federal do Rio de Janeiro, 21949-902 Rio de Janeiro, RJ (Brazil); Universidade Federal de Santa Catarina, Departamento de Biologia Celular, Embriologia e Genetica, Campus Universitario, 88040-900 Florianopolis, SC (Brazil); Ammar, Dib [Universidade do Oeste de Santa Catarina, Departamento de Biologia, Campus Universitario, 89600-000 Joacaba, SC (Brazil); Bem, Andreza Fabro de; Latini, Alexandra [Universidade Federal de Santa Catarina, Departamento de Bioquimica, Campus Universitario, 88040-900 Florianopolis, SC (Brazil); Mueller, Yara Maria Rauh [Universidade Federal de Santa Catarina, Departamento de Biologia Celular, Embriologia e Genetica, Campus Universitario, 88040-900 Florianopolis, SC (Brazil); Allodi, Silvana, E-mail: sallodi@histo.ufrj.br [Programa de Pos-Graduacao em Ciencias Morfologicas, Instituto de Ciencias Biomedicas, Universidade Federal do Rio de Janeiro, 21949-902 Rio de Janeiro, RJ (Brazil)

    2010-06-01

    The recent decrease of the stratospheric ozone has resulted in an increase of ultraviolet-B (UV-B) radiation reaching the Earth's surface. In freshwater ecosystems with transparent water, UV-B rays easily penetrate and potentially cause harmful effects to organisms. In this study, embryos of the prawn Macrobrachium olfersi were used to evaluate the impact of UV-B rays in freshwater environments. We observed three groups of embryos: the first was to assess whether UV-B radiation produced morphological defects and/or biochemical impairments in the laboratory. The second was to check whether embryos with the same impairments as those observed in the laboratory were found in their environment, under natural solar radiation. The third group was the non-irradiated control. The embryos irradiated with 310 mW cm{sup -2} UV-B for 30 min showed morphological alterations similar to those observed in embryos from the environmental control group. The most important effects of the UV-B radiation observed in M. olfersi embryos were morphological (1.2% of the total number of embryos from the environment and 2.8% of the total number of irradiated embryos), pigmentation changes in the eyes (78.0% of the total number of embryos from the environment and 98.9% of the total number of irradiated embryos), and disruption of the chromatophores (46.9% of the total number of embryos from the environment and 95.5% of the total number of irradiated embryos). We also observed an increase in egg volume, which was accompanied by a significant increase in water content in UV-B irradiated groups when compared with aquaria control embryos. In addition, a significant decrease in the mitotic index in eggs exposed to UV-B radiation was detected (0.17 for the embryos from the aquaria control, 0.10 for the embryos of the environmental control, and 0.04 for the irradiated groups). The low levels of NPSH and high levels of TBARS indicated that UV-B rays directly compromised the antioxidant function of

  9. BIO-ORGANIC CHEMISTRY QUARTERLY REPORT. December 1961, January and February 1962

    Energy Technology Data Exchange (ETDEWEB)

    Various,

    1962-04-03

    Progress is reported in investigations on the polymerization of formaldehyde, ultraviolet irradiation of aqueous HC/sup 14/N, radiation chemistry of nucleic acid constituents, oxidation of free sugars and aldonic acid derivatives by Acetobacter suboxydans, preparation and isolation of C/sup 14/O/ sub 2/~ enzyme, metabolism of C/sup 14/-ribulose diphosphate by Nitrobacter agilis, C/sup 14/O/sub 2/ metabolism of Hordeum valgare seedlings during the development of the photosynthetic apparatus, location and chemical characterization of RNA in the chloroplasts of Spinacea oleracea, inhibition of dark bleaching by stroma extracts and by inert gases, ESR studies on chromatophores from Rhodospirillium rubrum and on quantasomes from spinach chloroplasts, and phthalocyanine manganese and etioporphyrin manganese complexes. (J.R.D.) It has been known for a hundred years that formaldehyde polymerizes to carbohydrate substances in alkaline media. Although the reaction has long attracted much attention, only recently has a detailed qualitative analysis of the products been carried out by chromatographic methods. We have started to re-examine this reaction by combining chromatography with radioactive tracer techniques in the hope of refining the quantitative aspects of the analysis. Our particular interest has been to develop methods for determining the relative proportions of ribose and ribulose in the mixtures of sugars formed in basic media, as well as under other polymerizing conditions. The finding of large amounts of these sugars might help to explain the occurrence of ribose as the only basic sugar in the fundamental replicating molecules--the nucleic acids. Formaldehyde is thought to have been present in the primitive reducing atmosphere which existed before life first appeared. The ribonucleic acids must have appeared in the constitution of reproducing systems at a very early stage in the development of living organisms. In this study, the polymerizations of formaldehyde

  10. A systematic revision of Tatia (Siluriformes: Auchenipteridae: Centromochlinae

    Directory of Open Access Journals (Sweden)

    Luisa Maria Sarmento-Soares

    Full Text Available The auchenipterid catfish genus Tatia is revised. Twelve species are recognized including three described as new. Tatia is diagnosed by the hyomandibula elongated anterodorsally, the anal-fin base of adult males reduced in length, and the caudal peduncle laterally compressed and deep with a middorsal keel. Tatia aulopygia occurs in the Madeira river drainage and is distinguished by the reduced cranial fontanel in adults and male modified anal fin with middle rays reduced in length. Tatia boemia, known from the upper Uruguay river drainage, is distinguished by its unique color pattern with dark chromatophores on the sides of body. Tatia brunnea from river basins in Suriname and French Guiana and the Negro river drainage, Amazon basin, is recognized by its wide head and mouth and by the male modified anal fin with sharply pointed tip. Tatia dunni, from the upper Amazon basin, is recognized by its narrow head, long postcleithral process in some specimens, and body coloration with irregular blotches or stripes. Tatia galaxias, endemic to the Orinoco river basin, is distinguished by its large eye and short snout. Tatia gyrina, distributed in the upper and central Amazon basin and in northern Suriname, has a uniquely reduced mesethmoid, slightly protruding lower jaw, second nuchal plate with slightly concave lateral borders, third nuchal plate reduced, small prevomer, low number of ribs, low number of vertebrae and sexual dimorphism regarding intumescent male genital papilla. Tatia intermedia, recorded from central and lower Amazon basin, Tocantins river, and coastal drainages in Guyana, Suriname, French Guiana, and eastern Pará State, Brazil, is distinguished by the short postcleithral process, small eye and long snout. Tatia neivai, from the upper Paraná river , Paraguay river and upper Paraíba do Sul river basin, is distinguished by its unique vertebral count and caudal-fin coloration consisting of transverse dark bars. Tatia strigata, from

  11. 中间球海胆(意)与光棘球海胆(裔)种间杂交及自繁后代生长与表型特征比较%Growth and phenotypic characteristics of interspecific hybrids of sea urchin Strongylocentrotus intermedius (♀) × S. nudus (♂) and purebred offsprings

    Institute of Scientific and Technical Information of China (English)

    亓守冰; 张伟杰; 常亚青; 田晓飞; 王海峰; 赵帅; 经晨晨

    2015-01-01

    The survival, growth performance[specific growth rate(SGR) and coefficient of variation (CV)] and phenotypic characteristics ( count of chromatophore cells and ossicle shape on tube feet, and spine length and col-or) were compared in sea urchin hybrid juveniles of Strongylocentrotus intermedius (♀) ×S. nudus (♂) and the two purebred sea urchin offsprings to evaluate the heterosis. The 90 d feeding trial showed that both S. intermedius and S. nudus had survival rate of 100%, and the hybrids 97% at the end of the experiment, without significant difference (P>0. 05). However, there was significantly higher SGR (4. 00 %/d) in the hybrids than that in the parents (2.91 %/d in S. intermedius and 3. 15 %/d in S. nudus)(P0. 05). From 60 days to 90 days, there was no significant difference among the three sea urchins ( P>0 . 05 ) . The hybrids had significantly higher coefficient of variation for body weight of (76. 12%) than the S. intermedius(52. 05%) and S. nudus (63. 81%) at the end of the experiment(P0.05);在0~60 d的养殖范围内,杂交海胆具有最快的特定生长率(4.00%/d),且显著高于中间球海胆(2.91%/d)和光棘球海胆(3.15%/d)(P0.05),60~90 d时,3种海胆的特定生长率之间均无显著性差异( P>0.05);试验结束时,杂交海胆体质量的变异系数(76.12%)显著高于光棘球海胆(63.81%)和中间球海胆(52.05%)(P<0.05),表明种间杂交显著增加了后代的遗传变异;光棘球海胆管足中色素细胞数量最多,中间球海胆最少,杂交海胆的色素细胞数量介于父母本之间;杂交海胆棘刺为浅紫色,介于中间球海胆的白色和紫海胆的深紫色之间,而棘长较父母本细短;与棘色和管足颜色不同,杂交海胆骨片两端的突起产生了新的变异。研究表明,在幼胆期杂交海胆的表型特征明显区别于父母本,具有更快的生长速度和更高的变异水平,具有较高的育种价值。

  12. 虹鳉透明突变的遗传特征及其组织学观察%The Genetic Characteristics and Histological Defects in Transparent Mutant of Guppy Poecilia reticulate

    Institute of Scientific and Technical Information of China (English)

    李凯彬; 常藕琴; 刘春; 王芳; 马必勇; 梁慧丽; 吴淑勤

    2011-01-01

    摘要:采用杂交方法对虹鳉(Poecilia reticulate)透明性状的遗传规律进行了研究。从F1自交和回交后代的表型分析,该性状由1对等位基因控制,呈隐性遗传,其遗传特征符合孟德尔基因分离定律。采用体视镜观察比较不同表型虹鳉体表色素细胞的差异,并应用石蜡切片和电镜技术对不同表型鱼的皮肤、腹膜等结构进行研究,结果显示,与野生型虹鳝比较,透明个体没有虹彩色素细胞。组织学研究表明,透明虹鳉皮肤和腹膜的结构基本完整,但缺少了虹彩色素细胞层。由于突变个体虹彩色素细胞的缺失,导致光线可透过身体,因而变得透明。虹鳉的透明突变并不致死,也可育,且能稳定遗传。不论幼鱼或成鱼,透明突变体的心、肝、肾、肠、鳔、鳃、脊椎等内部器官可肉眼直接观察,为相关实验提供了极大便利,是进行体内实验研究的优良材料。%The transparent mutant of Poecilia reticulate was hybrid with wild type for genetic study. The analysis of offspring phenotype showed that the transparent characteristics was recessively inherent, controlled by an allele in line with Mendelism. Stereomicroscopy was used to examine the types and patterns of chromatophores for each phenotype, and it was found that the transparent mutant exhibited loss of iridophore. The paraffin section examination and electronic microscopy on the skin and peritoneum of guppy showed that the transparent mutant had an intact structure of skin and peritoneum, except for the absence of iridophore layer in contrast to wild-type individual. Reflective iridophore was absent in transparent mutant to the penetration of light, resulting in transparent appearance. The mutants were healthy and fertile, showing a stably genetic trait, and the main internal organs, such as heart, liver, gut, gonads, kidney, gills, and spinal cord, were naked-eye visible in living fish

  13. 三聚氰胺对藻类的毒性效应及其机理研究%Toxic mechanism study of melamine on phytoplankton

    Institute of Scientific and Technical Information of China (English)

    玉宁; 梁辉朝; 许俊峰; 裴国凤

    2011-01-01

    dismutase and catalase in them, along with the toxic effect on algae of melamine. The results of our tests and measurements show that melamine has an apparently inhibiting effect on the growth of these algae. Moreover, the higher the concentration of melamine is, and the longer the time that algae cultured, the lower the chla content and the greater the toxic effect. At the same time, melamine proves to be able to induce fast-growth in these algae even at lower dosages. When the concentration of melamine was over 1 500 mg/L, its chla content would be reduced with the treating time. For example, at the concentration of less than 750 mg/L, chla content tended to increase gradually, though the increasing rate was lower than that of the controls.However, the malonic dialdehyde' s content of the three algae was found to rise with the melamine concentration increased, whereas the superoxide dismutase and catalase were detected to rise during the entire testing period. It has no apparent changes in the protein content.These physiological changes indicate the toxic mechanism of melamine on the algae might be that the decrease of the protected enzyme active in algae cells made the lipid peroxidation of cell biomembrane increased, whereas the structure and function of the chromatophore were affected. Perhaps, the decrease of ehla content in algae cells may influence the photosynthesis process.

  14. A systematic revision of Tatia (Siluriformes: Auchenipteridae: Centromochlinae

    Directory of Open Access Journals (Sweden)

    Luisa Maria Sarmento-Soares

    2008-01-01

    Full Text Available The auchenipterid catfish genus Tatia is revised. Twelve species are recognized including three described as new. Tatia is diagnosed by the hyomandibula elongated anterodorsally, the anal-fin base of adult males reduced in length, and the caudal peduncle laterally compressed and deep with a middorsal keel. Tatia aulopygia occurs in the Madeira river drainage and is distinguished by the reduced cranial fontanel in adults and male modified anal fin with middle rays reduced in length. Tatia boemia, known from the upper Uruguay river drainage, is distinguished by its unique color pattern with dark chromatophores on the sides of body. Tatia brunnea from river basins in Suriname and French Guiana and the Negro river drainage, Amazon basin, is recognized by its wide head and mouth and by the male modified anal fin with sharply pointed tip. Tatia dunni, from the upper Amazon basin, is recognized by its narrow head, long postcleithral process in some specimens, and body coloration with irregular blotches or stripes. Tatia galaxias, endemic to the Orinoco river basin, is distinguished by its large eye and short snout. Tatia gyrina, distributed in the upper and central Amazon basin and in northern Suriname, has a uniquely reduced mesethmoid, slightly protruding lower jaw, second nuchal plate with slightly concave lateral borders, third nuchal plate reduced, small prevomer, low number of ribs, low number of vertebrae and sexual dimorphism regarding intumescent male genital papilla. Tatia intermedia, recorded from central and lower Amazon basin, Tocantins river, and coastal drainages in Guyana, Suriname, French Guiana, and eastern Pará State, Brazil, is distinguished by the short postcleithral process, small eye and long snout. Tatia neivai, from the upper Paraná river , Paraguay river and upper Paraíba do Sul river basin, is distinguished by its unique vertebral count and caudal-fin coloration consisting of transverse dark bars. Tatia strigata, from