Control of the melanophores of the crab,Pachygrapsus marmoratus: Release of pigment dispersing and pigment concentrating neurohormones by amines

1. The black pigment, in the melanophores, of Pachygrapsus marmoralus, a crab, disperses in specimens on a black background and concentrates in specimens on a white background.2. Bilateral eyestalk ablation results in black pigment concentration.3. These melanophores are regulated by pigment dispersing and concentrating hormones.4. In intact Pachygrapsus, 5-hydroxytryptamine produces black pigment dispersion whereas dopamine produces black pigment concentration.5. Neither 5-hydroxytryptamine nor dopamine affects melanophores in isolated legs. Presumably, therefore, these amines affect melanophores of intact Pachygrapsus indirectly only; 5-hydroxytryptamine by stimulating release of black pigment dispersing hormone and dopamine by stimulating release of black pigment concentrating hormone.     

Defence function of pigmentocysts in the karyorelictid ciliate Loxodes striatus

The karyorelictid ciliate Loxodes striatus has pigment granules which are similar in size, structure and distribution to the pigmentocysts in the heterotrich ciliates, Blepharisma japonicum and Stentor coeruleus, which are known to be extrusomes for chemical defence against predators. We examined whether the pigment granules of L. striatus are also defensive organelles. We showed that: (1) pigment granules of L. striatus are extrusive organelles; (2) bleached cells of L. striatus produced by inducing a massive discharge of pigment granules are more vulnerable than normally pigmented cells to the raptorial ciliate Dileptus margaritifer and the turbellarian Stenostomum sphagnetorum, while they are indistinguishable from intact cells in external morphology and the capacity to grow; (3) the cell-free fluid (CFF) which contains the pigment discharged from pigment granules of L. striatus induced in D. margaritifer behavioural and pathological reactions which are essentially the same as those observed in the interaction with L. striatus, and this effect of the CFF disappeared when the pigment was bleached by light. We conclude that pigment granules of L. striatus are extrusomes for chemical defence against predators, and that the defence is based on the toxic pigment contained in these organelles.     

Occurrence of xanthommatin containing pigment granules in the epidermal cells of the silkworm,Bombyx mori

A new type of pigment granule was found in the epidermal cells of the quail mutant of the silkworm, Bombyx mori. Electron microscopic observation shows this granule to be dense and distinct from the translucent pteridine granule. After the granules were isolated by sucrose density gradient centrifugation, the pigment was extracted and identified as xanthommatin.Xanthommatin localizes in the pigment granules binding with a protein. By SDS-polyacrylamide gel electrophoresis, the molecular weight of the pigment protein was estimated to be 13 kDa. The pigment granules may have a role in the biosynthesis and accumulation of xanthommatin.     

Propionibacterium jensenii Produces the Polyene Pigment Granadaene and Has Hemolytic Properties Similar to Those of Streptococcus agalactiae

The red polyene pigment granadaene was purified and identified from Propionibacterium jensenii. Granadaene has previously been identified only in Streptococcus agalactiae, where the pigment correlates with the hemolytic activity of the bacterium. A connection between hemolytic activity and the production of the red pigment has also been observed in P. jensenii, as nonpigmented strains are nonhemolytic. The pigment and hemolytic activity from S. agalactiae can be extracted from the bacterium with a starch extraction solution, and this solution also extracts the pigment and hemolytic activity from P. jensenii. A partial purification of the hemolytic activity was achieved, but the requirement for starch to preserve its activity made the purification unsuccessful. Partially purified hemolytic fractions were pigmented, and the color intensity of the fractions coincided with the hemolytic titer. The pigment was produced in a soluble form when associated with starch, and the UV-visual spectrum of the extract gave absorption peaks of 463 nm, 492 nm, and 524 nm. The pigment could also be extracted from the cells by a low-salt buffer, but it was then aggregated. The purification of the pigment from P. jensenii was performed, and mass spectrometry and nuclear magnetic resonance analysis revealed that P. jensenii indeed produces granadaene as seen in S. agalactiae.     

The nature of the lamprey visual pigment

From the retina of the land-locked population of the sea lamprey, Petromyzon marinus, a photolabile pigment was extracted which was identified spectrophotometrically as a member of the rhodopsin group of pigments. Using the absorption spectrum of a relatively pure solution and analysis by means of difference spectra, the peak of this pigment was placed at about 497 mµ. The method of selective bleaching by light of different wave lengths revealed no significant amounts of any other pigment in the extracts. A similar pigment was also detected in retinal extracts of the Pacific Coast lamprey, Entospenus tridentatus. These results are significant for two reasons: (a) the lamprey is shown to be an example of an animal which spawns in fresh water but which is characterized by the presence of rhodopsin, rather than porphyropsin, in the retina; (b) the primitive phylogenetic position of the lamprey suggests that rhodopsin was the visual pigment of the original vertebrates.     

Inhibitory effects of dibutyryl cyclic AMP and theophylline on the melanosome transformation in the embryonic chick pigmented retina cultured in vitro.

When the retinal pigment epithelial cells of chick embryo are cultured in monolayer conditions, the pigment granules are lost from the cytoplasm. The first structural change in depigmentation is the transformation of pigment granules into the degradative organelles designated as the dense body and melanosome complex. The cells are grown in medium containing DBcAMP of various doses from 10^?5 to 10^?2M. Cell proliferation is retarded by treatment with DBcAMP (10^?3M). The transformation of pigment granules is almost completely prevented in all 1-day cultured cells. In 5-day cultured cells continuously treated with more than 10^?4M, the transformation is not only prevented, but the synthesis of pigment granules is stimulated. A similar result is obtained by the administration of 10^?3M theophylline. 5′-AMP does not prevent the transformation of pigment granules but seems to stimulate the synthesis of pigment granules. On the other hand, cGMP is ineffective both on prevention of transformation and on synthesis of pigment granules. The mechanisms of the transformation of pigment granules are discussed.     

Improvement of the production of a red pigment in Penicillium sp. HSD07B synthesized during co-culture with Candida tropicalis

Co-culture of Penicillium sp. HSD07B and Candida tropicalis resulted in the production of a red pigment consisting of six components as determined by TLC and HPLC. The pigment showed no acute toxicity in mice and was mot mutagenic in the Ames test. The pigment was stable between pH 2 and 10 and temperatures of 10-100 °C and exhibited good photo-stability and resistance to oxidization by hydrogen peroxide and reduction by Na₂SO₃. Glucose and ratio of C. tropicalis to strain HSD07B (w/w) in the inoculum were the important factors influencing production of the pigment. Under optimized conditions, a pigment yield of 2.75 and 7.7 g/l was obtained in a shake-flask and a 15 l bioreactor, respectively. Thus, co-culture of strain HSD07B and C. tropicalis is a promising way to produce a red pigment potentially useful for coloring applications.     

Biosynthesis and Functions of a Melanoid Pigment Produced by Species of the Sporothrix Complex in the Presence of l-Tyrosine

Sporothrix schenckii is the etiological agent of sporotrichosis, the main subcutaneous mycosis in Latin America. Melanin is an important virulence factor of S. schenckii, which produces dihydroxynaphthalene melanin (DHN-melanin) in conidia and yeast cells. Additionally, l-dihydroxyphenylalanine (l-DOPA) can be used to enhance melanin production on these structures as well as on hyphae. Some fungi are able to synthesize another type of melanoid pigment, called pyomelanin, as a result of tyrosine catabolism. Since there is no information about tyrosine catabolism in Sporothrix spp., we cultured 73 strains, including representatives of newly described Sporothrix species of medical interest, such as S. brasiliensis, S. schenckii, and S. globosa, in minimal medium with tyrosine. All strains but one were able to produce a melanoid pigment with a negative charge in this culture medium after 9 days of incubation. An S. schenckii DHN-melanin mutant strain also produced pigment in the presence of tyrosine. Further analysis showed that pigment production occurs in both the filamentous and yeast phases, and pigment accumulates in supernatants during stationary-phase growth. Notably, sulcotrione inhibits pigment production. Melanin ghosts of wild-type and DHN mutant strains obtained when the fungus was cultured with tyrosine were similar to melanin ghosts yielded in the absence of the precursor, indicating that this melanin does not polymerize on the fungal cell wall. However, pyomelanin-producing fungal cells were more resistant to nitrogen-derived oxidants and to UV light. In conclusion, at least three species of the Sporothrix complex are able to produce pyomelanin in the presence of tyrosine, and this pigment might be involved in virulence.     

Purification and identification of chlorophyll c1 from the green alga Mantoniella squamata

The prasinophycean alga Mantoniella squamata contains besides chlorophyll a and b a third chlorophyll c-like pigment in its light-harvesting antenna. This third chlorophyll was purified by reverse phase and polyethylene chromatography in order to identify its chemical structure. The absorption and fluorescence spectra were measured not only from the doubly purified pigment, but also from its Mg-free derivates. The spectra were compared with those of authentic chlorophyll c and of Mg-2,4-desethyl-2,4-divinylpheoporphyrin a₅ monomethyl ester which was isolated from Rhodobacter capsulata. The results show that the pigment from Mantoniella agrees best with chlorophyll c₁. In order to clarify the spectral data, chlorophyll c₁ and c₂, the pigment from Mantoniella and Mg-2,4-desethyl-2,4-divinylpheoporphyrin a₅ monomethyl ester were resolved by polyethylene chromatography. The chromatographic analysis clearly shows that the pigment from Mantoniella comigrates with chlorophyll c₁ and not with the bacterial pigment or chlorophyll c₂. Mantoniella is the first organism which has been demonstrated to contain chlorophyll a, b and c.     

The blue anthocyanin pigments from the blue flowers of Heliophila coronopifolia L. (Brassicaceae)

Six acylated delphinidin glycosides (pigments 1-6) and one acylated kaempferol glycoside (pigment 9) were isolated from the blue flowers of cape stock (Heliophila coronopifolia) in Brassicaceae along with two known acylated cyanidin glycosides (pigments 7 and 8). Pigments 1-8, based on 3-sambubioside-5-glucosides of delphinidin and cyanidin, were acylated with hydroxycinnamic acids at 3-glycosyl residues of anthocyanidins. Using spectroscopic and chemical methods, the structures of pigments 1, 2, 5, and 6 were determined to be: delphinidin 3-O-[2-O-(β-xylopyranosyl)-6-O-(acyl)-β-glucopyranoside]-5-O-[6-O-(malonyl)-β-glucopyranoside], in which acyl moieties were, respectively, cis-p-coumaric acid for pigment 1, trans-caffeic acid for pigment 2, trans-p-coumaric acid for pigment 5 (a main pigment) and trans-ferulic acid for pigment 6, respectively. Moreover, the structure of pigments 3 and 4 were elucidated, respectively, as a demalonyl pigment 5 and a demalonyl pigment 6. Two known anthocyanins (pigments 7 and 8) were identified to be cyanidin 3-(6-p-coumaroyl-sambubioside)-5-(6-malonyl-glucoside) for pigment 7 and cyanidin 3-(6-feruloyl-sambubioside)-5-(6-malonyl-glucoside) for pigment 8 as minor anthocyanin pigments. A flavonol pigment (pigment 9) was isolated from its flowers and determined to be kaempferol 3-O-[6-O-(trans-feruloyl)-β-glucopyranoside]-7-O-cellobioside-4′-O-glucopyranoside as the main flavonol pigment.On the visible absorption spectral curve of the fresh blue petals of this plant and its petal pressed juice in the pH 5.0 buffer solution, three characteristic absorption maxima were observed at 546, 583 and 635 nm. However, the absorption curve of pigment 5 (a main anthocyanin in its flower) exhibited only one maximum at 569 nm in the pH 5.0 buffer solution, and violet color. The color of pigment 5 was observed to be very unstable in the pH 5.0 solution and soon decayed. In the pH 5.0 solution, the violet color of pigment 5 was restored as pure blue color by addition of pigment 9 (a main flavonol in this flower) like its fresh flower, and its blue solution exhibited the same three maxima at 546, 583 and 635 nm. On the other hand, the violet color of pigment 5 in the pH 5.0 buffer solution was not restored as pure blue color by addition of deacyl pigment 9 or rutin (a typical flower copigment). It is particularly interesting that, a blue anthocyanin-flavonol complex was extracted from the blue flowers of this plant with H₂O or 5% HOAc solution as a dark blue powder. This complex exhibited the same absorption maxima at 546, 583 and 635 nm in the pH 5.0 buffer solution. Analysis of FAB mass measurement established that this blue anthocyanin-flavonol complex was composed of one molecule each of pigment 5 and pigment 9, exhibiting a molecular ion [M+1] ⁺ at 2102 m/z (C₉₃H₁₀₅O₅₅ calc. 2101.542). However, this blue complex is extremely unstable in acid solution. It really dissociates into pigment 5 and pigment 9.     

Characterization and antifungal activity of the yellow pigment produced by a Bacillus sp. DBS4 isolated from the lichen Dirinaria agealita

This study emphasis the production of yellow pigment from endolichenic Bacillus sp. isolated from the lichen Dirinaria aegialita (Afzel. ex Ach.) B.J. Moore. Yellow pigment-producing twenty different strains were investigated. The hyperactive pigment-producing bacterial strain was identified as Bacillus gibsonii based on 99 % sequence similarity. Maximum bacterial pigment production appeared in Luria Bertani medium. Methanol extraction of the pigment and its partial purification using TLC was carried out. Furthermore, isolated pigments were characterized using UV-visible spectroscopy, FTIR spectroscopy, and GC-MS results related to the possibility of the carotenoid occurrence. The pigment also exhibited efficient antifungal activity against selected fungal pathogens of economic importance. Likewise, the pigment extract evaluated for the total antioxidant potential using Phosphomolybdenum and Ferric reducing antioxidant power assay and the results represented in Ascorbic Acid Equivalent (AAE)- 21.45 ± 1.212 mg/mL. The SC₅₀ of the pigment extract found to be 75.125 ± 0.18 µg/ml determined by the ABTS assay.     

The glucose metabolic frame of conditions induce the overproduction of a co-culture pigment: induction mechanism of the pigment and development of a specific eutrophic–oligotrophic transition cultivation system

Induction mechanism of a potential red pigment (RPc) was investigated in the present paper. A typical competition relationship exists between Penicillium sp. HSD07B and Candida tropicalis during co-culture, and C. tropicalis converts glucose into glycerol, organic acids and other substances, resulting in a stricter glucose limitation and the secretion of RPc. Moreover, a novel eutrophic–oligotrophic transition cultivation system (E-OTCS) was developed to produce red pigment during monoculture of Penicillium sp. HSD07B. However, the monoculture pigment (RPm) is different from RPc in components, and RP3 and RP4 only occur in RPm when glycerol is supplied. In addition, the additions of glycerol and organic acids to glucose exhaustion medium can significantly improve the pigment yield. These facts not only prove the feasibility of producing RPm using E-OTCS, but also reveal that, besides glucose exhaustion, the accumulation of metabolites of glucose including glycerol and organic acids is also an important factor influencing the production of RPc.     

Isolation of a blue-violet pigment from the flowers ofPlatycodon grandiflorum

A blue violet pigment was isolated in a crystalline state from the flowers ofPlatycodon grandiflorum A. DC. by the use of neutral solvents. The absorption spectrum of this pigment in buffer solution (pH 4.5) was almost identical with that of an intact tissue. The essential component of this pigment is platyconin, i.e., delphinidin 3-dicaffeoylrutinosido-5-glucoside.     

Elimination of egg pigment from developing ocular tissues in the frog Rana pipiens

The method by which egg pigment is eliminated from the developing retina, corneal epithelium and lens in Rana pipiens was studied with light and electron microscopy. The retina expells egg pigment into the space between the retina and pigment epithelium. This pigment is then engulfed by the pigment epithelial cells. The corneal epithelium eliminates egg pigment directly to the outside via the free surface of the epithelial cells. Egg pigment accumulates in a few cells in the lens. These cells probably degenerate and are extruded. These ectodermal derivatives in the eye are free of egg pigment long before ectodermal derivatives in other parts of the embryo lose their pigment. The early elimination of egg pigment from ocular tissues may related to the fact that these tissues must be transparent in order that light may pass freely to the photoreceptors.     

Studies on the Relation between the Pigment Migration and the Sensitivity Changes during Dark Adaptation in Diurnal and Nocturnal Lepidoptera

The functional significance of the pigment migration in the compound insect eye during dark adaptation has been studied in diurnal and nocturnal Lepidoptera. Measurements of the photomechanical changes were made on sections of eyes which had been dark-adapted for varying periods of time. In some experiments the sensitivity changes during dark adaptation were first determined before the eye was placed in the fixation solution. No change in the position of the retinal pigment occurred in Cerapteryx graminis until the eye had been dark-adapted for about 5 minutes. The start of the migration was accompanied by the appearance of a break in the dark adaptation curve. During longer periods of dark adaptation the outward movement of the pigment proceeded in parallel with the change in sensitivity, the migration as well as the adaptive process being completed within about 30 minutes. In the diurnal insects chosen for the present study (Erebia, Argynnis) the positional changes of the retinal pigment were insignificant in comparison with the movement of the distal pigment in Cerapteryx graminis. On the basis of these observations the tentative hypothesis is put forward that the second phase of adaptive change in nocturnal Lepidoptera is mediated by the migration of the retinal pigment while the first phase is assumed to be produced by the resynthesis of some photochemical substance. In diurnal insects which have no appreciable pigment migration the biochemical events alone appear to be responsible for the increase in sensitivity during dark adaptation.     

Interference by pigment in the estimation of microalgal biomass concentration by optical density

Optical density is used as a convenient indirect measurement of biomass concentration in microbial cell suspensions. Absorbance of light by a suspension can be related directly to cell density using a suitable standard curve. However, inaccuracies can be introduced when the pigment content of the cells changes. Under the culture conditions used, pigment content of the microalga Chlorella vulgaris varied between 0.5 and 5.5% of dry weight with age and culture conditions. This led to significant errors in biomass quantification over the course of a growth cycle, due to the change in absorbance. Using a standard curve generated at a single time point in the growth cycle to calculate dry weight (dw) from optical density led to average relative errors across the growth cycle, relative to actual dw, of between 9 and 18% at 680 nm and 5 and 13% at 750 nm. When a standard curve generated under low pigment conditions was used to estimate biomass under normal pigment conditions, average relative errors in biomass estimation relative to actual dw across the growth cycle were 52% at 680 nm and 25% at 750 nm. Similar results were found with Scenedesmus, Spirulina and Nannochloropsis. Suggested strategies to minimise error include selection of a wavelength that minimises absorbance by the pigment, e.g. 750 nm where chlorophyll is the dominant pigment, and generation of a standard curve towards the middle, or across the entire, growth cycle.     

The Luminosity Curve of the Protanomalous Fovea

Threshold spectral sensitivities (in the dark, or against bright colored backgrounds) are identical in the red-green range for both protanopes (dichromats) and protanomalous trichromatic color defectives. The latter, however, must have an additional photolabile cone pigment in the red-green range, and its presence is revealed by heterochromatic brightness matching through the spectrum (i.e. luminosity curves). The absorption spectrum of the anomalous cone pigment can be inferred from the protanomalous and protanopic luminosity curve, given reasonable assumptions as to how the different cone mechanisms pool their responses. Depending upon these assumptions, the pigment inferred is either (a) dilute solution of the normal red pigment (assumed density 1.0 for the deuteranope) or (b) similar in its absorption spectrum to the normal green pigment but shifted slightly toward the long wave end of the spectrum. Experimental attempts to choose between these alternatives have so far proved equivocal though (b) seems more likely on the basis of indirect evidence.     

Construction of a new cloning vector utilizing a cryptic plasmid and the highly expressed melanin-synthesizing gene operon from Streptomyces castaneoglobisporus

Streptomyces castaneoglobisporus HUT6202 overproduces a diffusible melanin pigment and harbors a cryptic 7.4-kb plasmid, pHY6202. We constructed a Streptomyces cloning vector, pSY10CMM, consisting of the HUT6202 rep gene, the thiostrepton resistance gene and an operon encoding the synthesis of melanin pigment, abbreviated mel, from S. castaneoglobisporus. The vector, which has SphI and BamHI sites as cloning sites with insertional inactivation of the mel, is a more convenient cloning vector than commonly used pIJ702, because of its broad host range for antibiotic-producing Streptomyces strains and its much greater production of diffusible melanin pigment.     

Expressions of the prefertilization polar axis in sea urchin eggs

The distribution of pigment granules in eggs of three species of sea urchins is described with reference to developmental stage and an egg's animal-vegetal axis of organization. Polarity in unfertilized sea urchin eggs has been a debated subject; present evidence demonstrates that the animal-vegetal axis is established before fertilization. The pigment pattern in some batches of Paracentrotus eggs exhibiting the celebrated “pigment band,” originally described by Theodor Boveri, is revised and is interpreted as a comparatively precocious expression of the underlying egg polarity. “Unbanded” Paracentrotus eggs and eggs of Arbacia lixula and Arbacia punctulata can be induced to exhibit the same pigment pattern by artificial activation. The induced pigment pattern aligns with an axis defined by polar bodies and the jelly canal, which are two external markers of the animal pole which are only rarely seen. It is therefore concluded that all of these eggs possess an animal-vegetal axis before fertilization even though it usually remains unexpressed until later developmental stages. Polarized changes in pigmentation are consistent with the following general mechanism: A change is triggered in the cortex of the vegetal pole; the change is programmed for a time which corresponds to the fourth mitotic division, even though mitosis itself is not involved; activation at fertilization initiates the “clock” in most cases, although in “banded” Paracentrotus eggs the “clock” is apparently started before ovulation; only the vegetal hemisphere's pigment is affected by the change. The nature of the underlying axis which defines animal and vegetal poles is discussed. Aspects of the axis have been tentatively traced back to the primary oocyte stage, but its fundamental nature remains unknown.     

The Luminosity Curve of the Deuteranomalous Fovea

Analogous to protans, the two types of deutan color-defectives—the dichromats (deuteranopes) and the anomalous trichromats (deuteranomalous)—do not differ in spectral sensitivity in the red-green range at threshold (either in the dark or against bright colored backgrounds). However, luminosity curves obtained by heterochromatic brightness matching show the latter to be slightly more sensitive in the blue-green, and slightly less so in the red, than the former. Experiment proves that these differences are due (at least in part) to contributions of cones containing the deuteranomalous anomalous pigment which are missing from the deuteranope's eye. The absorption spectrum of the anomalous pigment can be inferred with assumptions (analogous to those already made with protanomalous trichromats) about how the different cone mechanisms pool their responses to yield luminosity. Two alternatives thus revealed are (a) the normal red pigment in dilute solution or (b) a spectrum very similar to that of the normal red pigment but shifted slightly toward the short wave end of the spectrum. Since the spectrum inferred by (a) has the same λ_max as the normal red pigment, (a) predicts that deuteranomalous observers will require a negative red primary when matching monochromatic lights of wavelengths near the λ_max. This is not observed.