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PubMed1997

Photochemical and biochemical properties of chicken blue-sensitive cone visual pigment.

Through low-temperature spectroscopy and G-protein (transducin) activating experiments, we have investigated molecular properties of chicken blue, the cone visual pigment present in chicken blue-sensitive cones, and compared them with those of the other cone visual pigments, chicken green and chicken red (iodopsin), and rod visual pigment rhodopsin. Irradiation of chicken blue at -196 degrees C results in formation of a batho intermediate which then converts to BL, lumi, meta I, meta II, and meta III intermediates with the transition temperatures of -160, -110, -40, -20, and -10 degrees C. Batho intermediate exhibits an unique absorption spectrum having vibrational fine structure, suggesting that the chromophore of batho intermediate is in a C6-C7 conformation more restricted than those of chicken blue and its isopigment. As reflected by the difference in maxima of the original pigments, the absorption maxima of batho, BL, and lumi intermediates of chicken blue are located at wavelengths considerably shorter than those of the respective intermediates of chicken green, red and rhodopsin, but the maxima of meta I, meta II, and meta III are similar to those of the other visual pigments. These facts indicate that during the lumi-to-meta I transition, retinal chromophore changes its original position relative to the amino acid residues which regulate the maxima of original pigments through electrostatic interactions. Using time-resolved low-temperature spectroscopy, the decay rates of meta II and meta III intermediates of chicken blue are estimated to be similar to those of chicken red and green, but considerably faster than those of rhodopsin. Efficiency in activating transducin by the irradiated chicken blue is greatly diminished as the time before its addition to the reaction mixture containing transducin and GTP increases, while that by irradiated rhodopsin is not. The time profile is almost identical with those observed in chicken red and green. Thus, the faster decay of enzymatically active state is common in cone visual pigments, independent of their spectral sensitivity.

Animals↗
PubMed1999

Chloride binding regulates the Schiff base pK in gecko P521 cone-type visual pigment.

The binding of chloride is known to shift the absorption spectrum of most long-wavelength-absorbing cone-type visual pigments roughly 30 nm to the red. We determined that the chloride binding constant for this color shift in the gecko P521 visual pigment is 0.4 mM at pH 6.0. We found an additional effect of chloride on the P521 pigment: the apparent pKa of the Schiff base in P521 is greatly increased as the chloride concentration is increased. The apparent Schiff base pKa shifts from 8.4 for the chloride-free form to >10.4 for the chloride-bound form. We show that this shift is due to chloride binding to the pigment, not to the screening of the membrane surface charges by chloride ions. We also found that at high pH, the absorption maximum of the chloride-free pigment shifts from 495 to 475 nm. We suggest that the chloride-dependent shift of the apparent Schiff base pKa is due to the deprotonation of a residue in the chloride binding site with a pKa of ca. 8.5, roughly that of the Schiff base in the absence of chloride. The deprotonation of this site results in the formation of the 475 nm pigment and a 100-fold decrease in the pigment's ability to bind chloride. Increasing the concentration of chloride results in the stabilization of the protonated state of this residue in the chloride binding site and thus increased chloride binding with an accompanying increase in the Schiff base pK.

Animals↗
PubMed1999

Effect of pepper lipoxygenase activity and its linked reactions on pigments of the pepper fruit.

The products formed during the enzymatic reaction catalyzed by the lipoxygenase of pepper (variety Agridulce) have in vitro a strong destructive action on the carotenoid pigments of the fruit. When conditions and proportions of enzyme and pigments are similar to those found in the fruit, and at a reaction temperature of 20 degrees C, almost 30% of the pigments are destroyed after 24 h of reaction. Of this amount, 2.5% is due to autoxidation of pigments, 4. 5% to oxidation induced by the presence of linoleic under saturating conditions, and the remaining 22% to the presence in the medium of reaction products of the lipoxygenase-catalyzed reaction. When the enzyme acts under substrate-saturating conditions, the rate of pigment destruction by lipoxygenase can be considered maximal at the experimental temperature. The fact that in vitro pepper lipoxygenase induces a heavy destruction of pigments and that, in vivo, its activity remains almost constant during over-ripening could explain why up to 40% of the pigment content in some varieties is lost during the postharvest period.

Fruit↗
PubMed2002

Process of pigment cell specification in the sand dollar, Scaphechinus mirabilis.

The process of pigment cell specification in the sand dollar Scaphechinus mirabilis was examined by manipulative methods. In half embryos, which were formed by dissociating embryos at the 2-cell stage, the number of pigment cells was significantly greater than half the number of pigment cells observed in control embryos. This relative increase might have been brought about by the change in the arrangement of blastomeres surrounding the micromere progeny. To examine whether such an increase could be induced at a later stage, embryos were bisected with a glass needle. When embryos were bisected before 7 h postfertilization, the sum of pigment cells observed in a pair of embryo fragments was greater than that in control embryos. This relative increase was not seen when embryos were bisected after 7 h postfertilization. From the size of blastomeres, it became clear that the 9th cleavage was completed by 7 h postfertilization. Aphidicolin treatment revealed that 10-15 pigment founder cells were formed. The results obtained suggest that the pigment founder cells were specified through direct cell contact with micromere progeny after the 9th cleavage, and that most of the founder cells had divided three times before they differentiated into pigment cells.

Animals↗
PubMed1999

Genetic analyses of visual pigments of the pigeon (Columba livia).

We isolated five classes of retinal opsin genes rh1(Cl), rh2(Cl), sws1(Cl), sws2(Cl), and lws(Cl) from the pigeon; these encode RH1(Cl), RH2(Cl), SWS1(Cl), SWS2(Cl), and LWS(Cl) opsins, respectively. Upon binding to 11-cis-retinal, these opsins regenerate the corresponding photosensitive molecules, visual pigments. The absorbance spectra of visual pigments have a broad bell shape with the peak, being called lambdamax. Previously, the SWS1(Cl) opsin cDNA was isolated from the pigeon retinal RNA, expressed in cultured COS1 cells, reconstituted with 11-cis-retinal, and the lambdamax of the resulting SWS1(Cl) pigment was shown to be 393 nm. In this article, using the same methods, the lambdamax values of RH1(Cl), RH2(Cl), SWS2(Cl), and LWS(Cl) pigments were determined to be 502, 503, 448, and 559 nm, respectively. The pigeon is also known for its UV vision, detecting light at 320-380 nm. Being the only pigments that absorb light below 400 nm, the SWS1(Cl) pigments must mediate its UV vision. We also determined that a nonretinal P(Cl) pigment in the pineal gland of the pigeon has a lambdamax value at 481 nm.

Amino Acid Sequence↗
PubMed2004

Pigmented plaque presentation of dematiaceous fungal keratitis: a clinicopathologic correlation.

PURPOSE: To evaluate the clinical, microbiologic, and histopathologic features of dematiaceous fungal keratitis cases presenting with pigmented, raised, plaque-like infiltrate. STUDY DESIGN: Consecutive case series. METHODS: Microbiology-proven cases of fungal keratitis presenting with a pigmented infiltrate were included in the study. A detailed clinical and microbiological evaluation was performed in all cases. The lesion was removed by superficial keratectomy, and the specimen was subjected to histopathologic examination. Patients presenting with a large infiltrate had penetrating keratoplasty, and the corneal button was submitted for histopathology examination. RESULTS: We enrolled 15 cases in the study. There were 11 men and 4 women. The mean age of the patients was 48.5 years (range 27-68 years). The patients presented to us with duration of symptoms ranging from 7 to 60 days (mean 27.6 +/- 15.6, median 30). The visual acuity was better than 20/200 in 9 (60%) cases. The infiltrate size varied from 4.3 to 64 mm2 (mean 26.9 +/- 16.6, median 22.5). Ten (66.7%) cases had a central infiltrate. The infiltrate was dry and raised, with brown to black pigmentation on its surface. Corneal scrapings revealed septate fungal filaments in all cases and the characteristic brown to black pigmentation of the fungal cell wall in 10 (66.7%) cases. Although there was a significant growth of dematiaceous fungi on culture in all cases, species identification could be done in 3 cases only. Examination of tissue sections revealed a carpet of pigmented fungal filaments on the corneal surface (n = 12, 92.3%) associated with mild to moderate inflammation (n = 11, 84.7%) and tissue destruction. Nine out of 11 cases that had keratectomy resolved with medical therapy. CONCLUSIONS: The pigmented plaque-like infiltrate in dematiaceous fungal keratitis consists of surface colonization of pigmented fungal filaments associated with mild to moderate inflammation and tissue destruction of the underlying corneal stroma.

Adult↗
PubMed1992

Carotenoid pigment levels in Staphylococcus aureus and sensitivity to oleic acid.

Staphylococcus aureus mutants lacking pigment, or expressing only low levels of pigment, were more sensitive to oleic acid than were the parent strain and mutants making more pigment than the parent. One class of mutants (colour index 5), although possessing significant levels of pigment, were nevertheless quite sensitive to oleic acid. This suggested that only certain carotenoids in the biosynthetic pathway were capable of imparting resistance to fatty acids. The phenotypic expression of pigment also affected the sensitivity of a strain to oleic acid. The parent S. aureus strain 18Z, when grown to express its maximal pigment potential, was more resistant to oleic acid than when it was grown to express minimal levels of pigment.

Carotenoids↗
PubMed1981

Genetic control of chloroplast pigment development in soybeans as a function of leaf and plant maturity.

Changes in the major chloroplast pigments of pigment-deficient genotypes of soybeans were studied as a function of leaf age and plant age. The trends of pigment development are plotted as a function of relative leaf age at two periods of plant development. Comparisons are made between aging leaves from different nodes and leaves of different ages from the same node. In addition, trends of pigment development are expressed as a ratio of pigment-deficient/normal genotypes for five different genotypes and seven sampling periods. Those genotypes that exhibit a lag in production of pigments during leaf development show a similar lag in overall plant pigment development.

Journal Article↗
PubMed1991

Relation between the incidence and level of pigment cell antibodies and disease activity in vitiligo.

Patients with vitiligo often have antibodies to pigment cells. To examine whether there is a relation between the presence of such antibodies and disease activity, sera of 24 patients with vitiligo (10 with active and 14 with inactive disease) and 19 normal individuals were tested for antibodies to pigment cell surface antigens using a live cell enzyme-linked immunoabsorbent assay. IgG pigment cell antibodies were present in 80% (eight of 10) of patients with active vitiligo but in none of those with inactive disease or in normal individuals. The antibody level of patients with active vitiligo (mean binding index [BI] 3.3 +/- 0.59) was significantly higher than in patients with inactive disease (BI 0.96 +/- 0.04) or normal individuals (BI 1.0 +/- 0.04, p less than 0.001). Antibodies present in eight patients with high titers of pigment cell antibodies reacted to three of four pigment cells but to only one of six unrelated cells. These findings indicate that a correlation exists between the incidence and level of pigment cell antibodies and the activity of vitiligo, and support the hypothesis that vitiligo is an autoimmune disease mediated by an immune reaction to pigment cells.

Antibodies↗
PubMed1992

Identification of pigment cell antigens defined by vitiligo antibodies.

Patients with vitiligo have circulating antibodies to pigment cells. To characterize this response further and to identify the antigens defined by vitiligo antibodies, sera of 23 patients with vitiligo and 22 patients with unrelated conditions were analyzed by immunoprecipitation and SDS-PAGE analysis of 125I-labeled cell antigens on pigment and control cells. Antibodies to pigment cell antigens were present in 18 (78%) of the patients with vitiligo but in only three (14%) of the control patients (p less than 0.05). The antibodies were directed to one or more antigens with molecular weight (MW) in kilodaltons (kD) of approximately 35, 40-45, 75, 90, or 150. The responses were most commonly directed to the 40-45-kD, 75-kD, and 90-kD antigens. Antibodies to these antigens were present in 74%, 57%, and 35% of vitiligo patients versus in 14%, 9%, and 0% of control individuals. The 35-kD and 90-kD antigens were preferentially expressed on human pigment cells, whereas the 40-45-, 75-, and 150-kD antigens were expressed on both pigment and control cells. These antigens were labeled by the lactoperoxidase technique, suggesting that they are cell surface antigens. These results confirm that antibodies to pigment cells are associated with vitiligo. These antibodies are directed to several cell surface antigens, some of which are preferentially expressed on pigment cells.

Antibodies↗
PubMed2004

Keratinocytes in the depigmented epidermis of vitiligo are more vulnerable to trauma (suction) than keratinocytes in the normally pigmented epidermis, resulting in their apoptosis.

BACKGROUND: Vitiligo may develop following minor physical trauma. However, in autologous epidermal grafting, depigmentation of the donor (normally pigmented) site from a suction blister is rare, even in cases displaying failure of repigmentation at the recipient (depigmented) site. OBJECTIVES: To examine whether the suction procedure is more likely to damage keratinocytes in the depigmented than in the normally pigmented epidermis of vitiligo, and to determine what kind of damage occurs to the keratinocytes. METHODS: Paired roofs of suction blisters from five patients with generalized vitiligo, five with localized and seven with segmental type, were used for the study. Multiple new lesions developed in two of the five patients with the generalized type. Apoptosis of keratinocytes in the epidermis was determined by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-digoxigenin nick end labelling (TUNEL) staining, with immunohistochemistry for Bax and active caspase 3. Expression of Bcl-2, Bax, FLIP and p53, activation of caspases 3, 8 and 9, and cleavage of poly(adenosine diphosphate ribose) polymerase (PARP) in the epidermis were analysed by Western blotting in four patients with each type. RESULTS: Apoptotic keratinocytes, which stained with TUNEL and anti-Bax and antiactive caspase 3 antibodies, were scattered in the blistered epidermis, mainly in the lower portions. The depigmented epidermis displayed significantly more apoptotic keratinocytes than the normally pigmented epidermis. The numerical difference between the paired epidermides was related to the disease activity and not to the type of lesions. The number of apoptotic keratinocytes in the normally pigmented epidermis was as high as that in the depigmented epidermis in the two patients with active generalized type vitiligo. Expression of Bax and p53 in the depigmented epidermis was higher than in the normally pigmented epidermis, whereas expression of FLIP was lower. In addition, the activation of caspases 3, 8 and 9, and cleavage of PARP, were increased in the depigmented compared with the normally pigmented epidermis. The degree of difference in expression and activation was parallel to the results of the TUNEL assay. CONCLUSIONS: The keratinocytes in the depigmented compared with the normally pigmented epidermis of vitiligo may become apoptotic more easily after suction.

Adolescent↗
PubMed1985

Vitiligo-related pigment cell differentiation antigens are expressed on malignant melanoma cells following phenotypic reversion induced by contact inhibitory factor.

Most vitiligo sera contain antibodies to surface antigens on pigmented human melanocytes but not to human or mouse amelanotic melanoma cells. A density-dependent line of hamster amelanotic melanocytic cells (FF) produces a diffusible factor (CIF) which restores contact inhibition of growth as well as several other normal phenotypic characteristics to hamster, murine, and human melanoma cells. The ability of CIF to induce the expression of a phenotypic characteristic of pigmented human melanocytic cells, i.e., the vitiligo-related surface antigens, on hamster and mouse amelanotic melanoma cells was investigated. Vitiligo and normal sera were reacted with CIF-treated and untreated hamster and mouse amelanotic melanoma cells for both indirect-immunofluorescence assays and ELISA. Immunofluorescence testing showed that about 80% of hamster and mouse melanoma cells had pigment-cell antigens (in the absence of pigmentation) in a granular surface pattern after, but not prior to, CIF-induced morphologic reversion and confluent growth. Less than 5% of the control hamster and mouse melanoma cells expressed such antigens at confluence. These results were confirmed by ELISA. Metabolic-labeling studies with 35S-methionine showed that the vitiligo antigens were synthesized by the CIF-treated melanoma cells. The slowing of melanoma cell proliferation in isoleucine-deficient medium failed to elicit the expression of vitiligo antigens. Since antigen appearance following phenotypic reversion occurred without pigment induction, it is concluded that vitiligo-related surface antigens and pigmentation are distinct aspects of a differentiated function which may be non-coordinately expressed. The expression of pigment-cell differentiation antigens on amelanotic melanoma cells is an additional feature of the pleiotypic trans-species response to CIF.

Animals↗
PubMed2004

Multiple pigmented follicular cysts of the vulva successfully treated with CO2 laser: case report and literature review.

BACKGROUND: A pigmented follicular cyst is an uncommon epithelial cyst, typically occurring as a single asymptomatic pigmented papule or nodule on the head and neck of adult men. To the authors' knowledge, no previous cases of vulvar pigmented follicular cyst have been reported. Although benign, pigmented follicular cyst can affect quality of life when multiple and symptomatic. OBJECTIVE: The objective was to describe the clinicopathologic features of vulvar pigmented follicular cyst and to evaluate the efficacy of CO(2) laser therapy in this region. METHODS: A 62-year-old woman with multiple pigmented follicular cysts affecting the labia majora bilaterally is described. Owing to frequent inflammation and tenderness, continuous-wave CO(2) laser was used to treat the skin lesions under local anesthesia. RESULTS: All cystic nodules were successfully ablated with CO(2) laser. The patient tolerated the procedure well and had a satisfactory cosmetic outcome. CONCLUSION: CO(2) laser is a tolerable and effective therapeutic modality for multiple and symptomatic pigmented follicular cysts of the vulva.

Carbon Dioxide↗
PubMed2006

Infrared spectra of U.S. automobile original finishes. VII. Extended range FT-IR and XRF analyses of inorganic pigments in situ--nickel titanate and chrome titanate.

The identification, analysis, and occurrence in U.S. automobile original finishes (1974-1989) of Nickel Titanate (yellow) and Chrome Titanate (yellow-orange) are described in this report. The titanate pigments are based on the rutile (titanium dioxide) structure and there are only minor differences between the infrared absorptions of rutile and the titanates. Titanate pigment absorptions in paint spectra can thus be easily mistaken for those of rutile. Each of the titanates, however, contains two elements in addition to titanium that can serve to distinguish them using elemental analyses. Fourier transform infrared (4000-220 cm(-1)) and X-ray fluorescence instruments were used in combination for the in situ analysis of the titanates. In addition to titanium, nickel, and antimony, the three main detectable elements comprising Nickel Titanate, all of the commercial products of this pigment that were examined also contained impurities of zirconium, niobium, and usually lead. These elements were also detected in most of the monocoats in which Nickel Titanate was identified, as well as in the Chrome Titanate pigments, and the zirconium to niobium ratio was found to exhibit a wide variation. Nickel Titanate is a relatively common pigment that was identified in nearly three dozen U.S. automobile yellow nonmetallic monocoats (1974-1989), while Chrome Titanate appears to have been used in only a few yellow and orange nonmetallic monocoats. The use of the titanate pigments likely increased after this time period as they were replacements for lead chromate pigments (last used in a U.S. automobile original finish in the early 1990s), and are more amenable for use in basecoat/clearcoat finishes than in monocoats. Minor distortions of the infrared absorptions of rutile, anatase, and the titanates obtained using accessories with diamond windows were noted, and their origins are discussed.

Journal Article↗
PubMed2004

Assessment of chamber angle pigmentation during longterm latanoprost treatment for open-angle glaucoma.

PURPOSE: This study aimed to determine whether the longterm use of latanoprost is associated with an increase in trabecular pigmentation, especially in subjects in whom iris pigmentation has increased. METHODS: We enrolled 50 subjects for whom treatment was to start for ocular hypertension, primary open-angle glaucoma or normal tension glaucoma. All subjects received latanoprost 0.005% daily. Trabecular pigmentation was documented using gonioscopic photography of the inferior quadrant at baseline, every 3 months for the first year and every 6 months for the second and third years. Three glaucoma specialists evaluated the series of gonioscopic photographs for each eye of each subject in a masked fashion. The intraocular pressure (IOP) was also recorded at each visit. RESULTS: A total of 41 subjects (79 eyes) completed 3 years of follow-up, and none showed any increase in the grade of trabecular pigmentation, including 10 subjects (20 eyes) in whom the iridial pigment increased. CONCLUSION: Although latanoprost increased iridial pigmentation in some subjects, we found no evidence of an increase in trabecular pigmentation over the 3 years of follow-up.

Antihypertensive Agents↗
PubMedDate not supplied

Drug-induced and genetic hypermelanism: effects on pigment cell differentiation.

Allopurinol, a drug that inhibits the enzyme xanthine dehydrogenase (XDH), is known to cause hypermelanism in the axolotl. The hypermelanistic condition that results from allopurinol treatment is similar in most respects to the phenotype that results from the action of the melanoid (m) gene in axolotls. On the basis of structural and biochemical studies, it now seems clear that genetic and drug-induced hypermelanism are the same in the following ways. 1) Both types of melanism result in the production of more than normal amounts of melanin and more melanin-containing cells (melanophores). 2) In both cases the amount of pteridine-associated yellow pigment declines during development, and this is associated directly with fine structural changes that occur within the pigment organelles (pterinosomes) of yellow pigment cells (xanthophores). 3) In both cases the hypermelanistic condition results in the suppression of reflecting pigment cell (iridophore) differentiation. 4) Both conditions have now been linked directly to depressed levels of XDH activity. Thus both genetic and drug-induced hypermelanism result in alterations in the normal differentiation of all three pigment cell types and the subsequent disruption of normal pigment pattern formation. The possible significance of these findings with regard to factors known or suspected to direct the migration and/or differentiation of neural crest-derived pigment cells is discussed.

Allopurinol↗
PubMed1975

Carotenoid pigments of facultatively anaerobic spirochetes.

Carotenoid pigments were purified from a previously undescribed, red, halophilic spirochete (spirochete RS1), and from Spirochaeta aurantia strain J1. Both spirochetes are facultative anaerobes and produce pigments when growing aerobically. The major pigments of the two spirochetes were identified by means of chromatographic analysis, absorption spectroscopy, hydride reduction, acetylation and silylation experiments, and mass spectrometry. It was concluded that the major pigment from spirochete RS1 was 4-keto-1',2'-dihydro-1'-hydroxytorulene. This conclusion was further supported by infrared spectroscopy and additional analytical data. The evidence showed that the major pigment from S. aurantia was 1',2'-dihydro-1'-hydroxytorulene. Chromatographic and spectrophotometric evidence indicated that this pigment was also present, as a minor carotenoid component, in spirochete RS1. These pigments have been previously detected almost exclusively in gliding bacteria, such as species of Flexibacter, Stigmatella, and Myxococcus. The occurrence of 4-keto-1',2'-dihydro-1'-hydroxytorulene and 1',2'-dihydro-1'-hydroxytorulene in both spirochetes and gliding bacteria may have significance with respect to the evolutionary development of these organisms.

Acetylation↗
PubMed1979

Macular pigment deposits in rhegmatogenous retinal detachment.

This is a study of 20 cases of macular migration after operation for retinal detachment. The frequency of pigment deposits on the macula among the total number of operated detachments was 6.4%. The evolution of pigment migration depened on the form and type of the deposits. In some cases the pigment diminished or disappeared. In 6 of the 20 eyes with pigment migration puckering of the macula occurred 4 months or more after surgery. The improvement in visual acuity 6 months and more after operation was relatively less in the group with pigment deposits than in the group without pigment. In the former group static perimetry showed defects corresponding to the pigment migration.

Aged↗