Microspectroscopy of the Photosynthetic Compartment of Algae
We performed microspectroscopic evaluation of the pigment composition of the photosynthetic compartments of algae belonging to different taxonomic divisions and higher plants. The feasibility of microspectroscopy for discriminating among species and/or phylogenetic groups was tested on laboratory cultures. Gaussian bands decompositions and a fitting algorithm, together with fourth-derivative transformation of absorbance spectra, provided a reliable discrimination among chlorophylls a, b and c, phycobiliproteins and carotenoids. Comparative analysis of absorption spectra highlighted the evolutionary grouping of the algae into three main lineages in accordance with the most recent endosymbiotic theories.According to the most recent theories different evolutionary lineages can be recognized within the algal world (1,2). Three major eukaryotic photosynthetic groups have descended from a common prokaryotic ancestor through an endosymbiotic event. The result is a set of nested cellular compartments one inside the other and information about the evolutionary history of the organism can he gleaned from the study of the membranes surrounding these compartments, the genes that they express and their function. The three lineages of primary plastids were found in the Glaucophyta, in the green algae and plants and in the red algae. The other algal groups have acquired their plastids via secondary (or tertiary) endosymbiosis, in which a eukaryote already equipped with plastids was preyed upon by a second eukaryotic cell. An endosymbiotic process produced nested photosynthetic compartments one inside the other, which can give information about the evolutionary history of the algae containing them (3,4).
9-cis Retinal Increased in Retina of RPE65 Knockout Mice with Decrease in Coat Pigmentation[dagger]
The protein RPE65 is essential for the generation of the native chromophore, 11-cis retinal, of visual pigments. However, the Rpe65 knockout (Rpe65^sup -/-^) mouse shows a minimal visual response due to the presence of a pigment, isorhodopsin, formed with 9-cis retinal. Isorhodopsin accumulates linearly with prolonged dark-rearing of the animals. The majority of Rpe65^sup -/-^ mice have an agouti coat color. A tan coat color subset of Rpe65^sup -/-^ mice was found to have an enhanced visual response as measured by electroretinograms. The enhanced response was found to be due to increased levels of 9-cis retinal and isorhodopsin pigment levels. Animals of both coat colors reared in cyclic light have minimal levels of regenerated pigment and show photoreceptor degeneration. On dark-rearing, pigment accumulates and photoreceptor degeneration is decreased. In the tan Rpe65^sup -/-^ mice, the level of photoreceptor degeneration is less than in the agouti animals, which have an increased pigment and decreased free opsin level. Therefore, photoreceptor damage correlates with the amount of the apoprotein present, supporting findings that the activity from unregenerated opsin can lead to photoreceptor degeneration.
The Rpe65^sup -/-^ mouse has been shown to have a minimal response to light by electroretinogram (ERG) measurements (6). In a previous study, we reported that endogenous 9-cis retinal accumulates and regenerates isorhodopsin through an Rpe65^sup -/-^ independent pathway during long term dark-rearing (7). Further, with single cell recordings we have confirmed that this response is due to the isorhodopsin pigment (8). The 9-cis retinal accumulation rate is very slow (~0.3 pmol/retina/day) in the normal agouti Rpe65^sup -/-^ mouse.
In this study, we show that a subset of Rpe65^sup -/-^ mice with a tan coat color exhibit enhanced ERG responses compared with usual agouti coat color Rpe65^sup -/-^ mice. The enhanced response is found to be due to increased levels of 9-cis retinal and isorhodopsin pigment levels. The increased pigment levels correlate with a decreased melanin level in the tan animals. The animals with higher pigment levels, and therefore decreased apoprotein opsin levels, showed a decrease in photoreceptor degeneration suggesting that the photoreceptor damage is resulting from basal opsin activity.
MATERIAL AND METHODS
Animals. Agouti and tan Rpe65^sup -/-^ mice were genotyped as previously described (6). Age-matched C57BL/6 and SV129 mice were purchased from Harlan Breeders (Indianapolis, IN). Animals were reared under cyclic light (12 h light/12 h dark, with the ambient light intensity at the eye level of the mice being 85 ± 18 lux) initially. Dark-rearing was initiated at 2 months-of-age. For dark rearing, the animal husbandry was performed under the dim red safety light (Kodak filter GBX-2). All experiments were performed in accordance with the policy on the Use of Animals in Neuroscience Research and were approved by the Medical University of South Carolina Animal Care and Use Committee.
Western blot analysis. Eyecups containing retinas were homogenized in 1% SDS buffer. Total proteins (60 µg) from each lysate were loaded onto 12% polyacrylamide gels and subjected to Western blot analysis using a 1:2000 dilution of primary antibodies as follows: the rabbit anti-RPE65 antibody was raised and characterized as in previous studies (9). The rabbit anti-IRBP antibody was generously provided by Barbara Wiggert, National Eye Institute. The mouse 1D4 antibody (Cellex Biosciences, Inc., Minneapolis, MN) was used for the opsin detection. The rabbit anti-RDH5 antibody was generated as previously reported (10). The mouse ?-actin antibody was purchased from Sigma. The secondary antibodies used were goat anti-rabbit IgG (1:10,000; Vector, Burlingame, CA) and horse anti-mouse IgG (1:10,000; Vector, Burlingame, CA).
ERG analysis. The experiments were performed as described previously (7,11). Briefly, animals were anesthetized by using a mixture of xylazine (20 mg/kg) and ketamine (80 mg/kg). Pupils were dilated with phenyl-ephrine hydrochloride (2.5%) and atropine sulfate (1%) separately. Contact lens electrodes (12) were placed on both eyes with the assistance of methylcellose. Full-field ERGs were recorded by using the universal testing and electrophysiologic system 2000 (UTAS E-2000, LKC Technologies, Gaithersburg, MD) in response to 10 µs single flashes of fixed intensity (2.48 photopic cd-s/m^sup 2^) under scotopic conditions. This intensity can cause saturated rod responses in C57BL/6 wild-type mice, but is not strong enough to saturate rod responses in Rpe65^sup -/-^ mice (13). This light intensity was used to minimize the bleaching of accumulated visual pigments (7). The amplitude of the a-wave was measured from the baseline to the lowest negative-going voltage. Data are presented as means ± SEM and analyzed by a one-tailed Student’s t-test, accepting a significance value of P ? 0.05
John Beech at Charlotte Jackson
Over the course of a 15-year career, John Beech has become known for wittily transforming–or appropriating the shapes of–everyday industrial objects such as car-floor mats, Dumpsters and parking-lot bumpers. This recent show comprised 11 works, mostly made in 2003 and 2004, from the four corners of his repertoire: the interactive “Rotating Paintings” made of wooden and Plexiglas disks affixed to lazy Susan hardware; the “Glue Paintings,” in which plywood structures are layered with colored glue; and two series of floor pieces, titled “Obstacles” and “Rolling Platforms.Though the artist acknowledges the influence of Donald Judd and the Minimalist esthetic, these geometric constructions are easily read as subversive offspring of Minimalism’s reductivist vocabulary. Frequently, Beech’s clever handcrafted assemblages juxtapose sleek and precisely calibrated surfaces with sections of raw plywood; sometimes he exposes the works’ bare backsides. Punctuated with spontaneous spills and splatterings of paint that often run over the edges and supports, these compositions also are a nod to Process art. For instance, Green Cube (2000), a mint-colored wall-hung box with a wide stripe of unpainted wood, incorporates metal pipes that serve as peepholes to allow the viewer to peer into its hollow interior. On the floor below Green Cube sat a mutant cube-shaped mover’s dolly in fire-engine red enamel–one of the “Rolling Platforms”–which appeared to sprout the paint-splattered casters screwed to its surfaces.
In contrast, Beech’s new additions to the “Glue Paintings” do not have the haphazard air of the earlier pieces; instead, these stark compositions are elegantly sensuous, almost despite themselves. They assume a variety of shapes, their opaque and delicately mottled monochrome surfaces achieved through the use of underpainting and meticulously brushed-on coatings of glue in which pigments have been suspended. (Previously, the “Glue Paintings” featured the “found” colors of particular brands or types of adhesive.)
Glue Painting #82, a chunky block that extends out from the wall, has smooth, faintly rippled salmon-colored surfaces. The piece’s singular lusciousness is also a product of gravity, which drew the viscous medium downward to form ridges of rounded saw-toothed peaks that subsequently hardened around the bottom edges and across the underside. These configurations, suggestive of water droplets or of frosting on a cake, curiously conjure the pastry displays found in Wayne Thiebaud’s paintings.
This emphasis on color and textural nuance in the later “Glue Paintings” obscures their humble origins while imbuing them with a meditative materiality that distinguished them from other pieces in the show. It will be interesting to see if this development in Beech’s practice signals an entirely new direction, or if it simply means that he’s about to come full circle
Dan Christensen at Edward Thorp
One of the earliest works in this nearly four-decade mini-retrospective of Dan Christensen’s paintings was a 1968 untitled 7 1/2-foot-high vision of twirling ribbons of color winding around each other in helix formations that seem barely contained by the canvas’s edges. Sprayed in liquid acrylic on an unprimed or neutral ground, a signature technique for Christensen in the 1960s, the multitude of intensely chromatic lines creates a densely inscribed but still airy allover surface that suggests Color Field painting, the style within which Christensen came to prominence. But here, as in several similar products of this technique–such as Conjugate (1967), a canvas in which the colored ribbons roll from side to side as they pile up in a vertical plane–there is a Slinky-like tautness and containment that distinguishes his work from that of Frankenthaler and Louis. In other works, such as Sarajevo (1969), the ground is composed of abutting fields of soft, muted hues, before which colored sinuous lines float through a misty space in ascending, interlocking loops, registering the movement of the artist’s arm as he made them.Later works return to the high-keyed hues and atmospheric effects of the ribbon canvases, but appear less completely devoted to the vicissitudes of pure paint and color, sometimes betraying a hint of figuration. Artic Pi (1989), an oval form painted in shimmering silver and ringed by colored bands, suggests a mirror. And a subsequent work, April Blue (1995), is a broad field of metallic marine interrupted by floating cell-like forms, recalling sea life, with soft, brightly colored haloes or penumbrae. Although many of these works hark back to the postpainterly abstract art of the ’60s, they are composed with novel pigments, metallics and pearlescents, and commercial colors, among other devices, that situate them in the near present. The bull’s-eye motif of Memo (1991), for example, in which a white circle surrounds a bright green disc, may imply the aspiration to purity and autonomy of the target paintings of Kenneth Noland. But in its silvery mint-green ground and cool white band edged in violet, it also conveys the experience of such everyday, debased phenomena as fluorescent light and the phosphorescent glow of a television’s cathode-ray tube.
Rose hips: powerful medicine for the heart and body: The rose, the national floral emblem of the United States, has always been valued for its beauty and fragrance. Cultivated for thousands of years, it became an ancient symbol of love and beauty. The Greeks and Romans identified this flower with their goddesses of love Aphrodite and Venus. Today, a gift of pink or red roses represents an expression of love and admiration
While the common rose originated in Iran, cultivation of the fragrant flower took off in Europe in the 1800’s with the introduction of roses from China that had an amazing ability to bloom repeatedly throughout the summer and into late autumn. Rose bushes have become one of the most popular garden shrubs, bearing flowers in a variety of colors: red, white, pink, yellow, orange, and burgundy. Currently, there are thousands of rose varieties and hybrids that have been developed for their bloom shape, color, size, and fragrance. Some even lack thorns Perfumes are made by steam-distilling crushed rose petals. About 60,000 flowers are required to produce 30 grams (1 oz.) of rose oil–a yellowish-grey liquid. Damask Roses are typically used. The main fragrant constituents of rose oil are terpenoids, geraniol, and citronellol. Today, about 70 to 80 percent of rose oil comes from Bulgaria, while the balance is manufactured in Iran and Germany.
In France’s perfume industry, Rosa. x centifolia is the variety of choice. The oil is popular in aromatherapy, is said to have mild sedative activity, and is used to treat anxiety and depression. Rose oil also serves as the anointing oil used in the coronation of British monarchs. Rose water–made from rose oil–flavors candy, desserts,
In addition to producing oil, rose petals are commonly used in potpourris and can be added to salads, jellies, and jams. The dried petals of Rosa gallica and Rosa x centifolia–which are rich in astringent tannins–find use in mouth rinses to treat mild inflammations.
Culinary Uses
Rose hips are the berry-like fruits left behind after the bloom has died. They’re typically red or orange, but may also be dark purple to black in some species. Although nearly all rose bushes produce rose hips, the tastiest for eating purposes come from the Rugusa Rose. Rose hips have a tangy, fruity flavor similar to that of cranberries, and are best harvested after the first frost, which turns them bright red and slightly soft. Rose hips were a popular food of Native Americans.
There are many culinary uses for rose hips. They can be used fresh, dried, or preserved and add flavor to applesauces, soups and stews, syrups, puddings, marmalades, tarts, breads, and pies, or are made into jams or jellies. Each rose hip comprises an outer fleshy layer which may contain up to 150 seeds embedded in a matrix of fine hairs. The irritating hairs should be removed before using the rose hips in a recipe.
Good Medicine
Rose hips of some species, especially the Dog Rose (Rosa canina) and Rugosa Rose (Rosa rugosa), are a rich source of vitamin C. With one to two percent vitamin C by dry weight, rose hips have a higher content of the vitamin than citrus fruit. During World War 11 when imports of citrus products to Great Britain were limited, tons of rose hips were harvested there from the wild to make rose hip syrup as a vitamin C supplement for children.
In AD 77 the Roman writer Pliny recorded 32 disorders that responded to treatment with rose preparations. Medieval herbals contained many entries that tell of the restorative properties of rose preparations.
The anti-inflammatory properties of rose hips have recently been shown to be useful in the treatment of patients suffering from knee or hip osteoarthritis–a degenerative joint disease affecting over 20 million Americans. The condition is characterized by the breakdown of cartilage in the joint, allowing bones to rub against each other, causing pain and loss of movement.
Scientists in Denmark reported that patients who daily consumed standardized rose hip powder (made from Dog Rose) experienced significantly less joint stiffness and pain, and an improved general well-being and mood after three to four months of treatment. The use of rose hip powder also enabled the patients to considerably reduce their standard pain medication. Rose hips contain high levels of antioxidant flavonoids with known anti-inflammatory properties.
Rainer Gross at Axel Raben
You can brush, trowel, throw, squirt, drip or pour paint onto a canvas, or stain it with diluted medium. It has all been done. Rainer Gross makes paint adhere to the support in yet another way in order to arrive at compelling abstract compositions. Since the early ’90s, this New York-based artist from Cologne has experimented with monotype techniques, here adapting them to create the body of paintings (”Contact Paintings”) that he displayed–together with six monotypes on paper–at Axel Raben
Gross first covers his linen support, placed horizontally, with three layers of dry, (usually) white pigment mixed with water, and then continues to apply successive monochrome or polychrome layers of dry pigments mixed with water, allowing each sufficient time to dry. Next, he takes another canvas of the same size and format, covers it with a thick coat of (usually) white oil paint, and places this canvas face down on top of its counterpart. He presses down on it so that the oil medium can seep through, and eventually he pulls the canvases apart. The result is that the surface patterns (though not always the colors) on the canvases roughly mirror each other. Gross obtains chipped and plastery-looking surfaces with a dense craquelure. He displays the paired canvases side by side or one above the other, though he may add a twist by turning one of them 180 degrees. The paintings are sold as pairs and are to be displayed as was determined by the artist. Gross, who is interested in Fluxus, finds titles for his pictures by randomly selecting names from the phonebook
These organic abstractions, with their saturated patches of color–a desiccated simulacrum of painterliness, in which process and chance play such a crucial role–evoke repeatedly repainted and weathered walls, as well as views of the earth’s topography as perceived from a great distance. With their layering and revealing, they remind one of the dechirages of Raymond Hains and Jacques de la Villegle and of the remnants of painted walls in the rubber castings of Robert Overby.
Omar Twins, with one vertical panel turned 180 degrees, consists of beiges, whites, deep blues and residues of olive green. Its palette and drifting plates evoke early Joan Mitchell and, more elliptically, the allover fields of late Monet. The larger Deura Twins, with its five fading vertical orange-red and blue bars per vertical panel, interspersed with beige and a yellow-green haze, reminds one of shredded flags. Gross’s ephemeral-looking work, alluding to the destructive forces of time, tackles the modernist tradition with zest
Johannes Girardoni at Stephen Haller
Pairing wax colored in rich hues with wood, Johannes Girardoni has concocted a winning combination. The texture and aroma of these works are as captivating as their curved forms and dramatic colors. The titles of the pieces (all 2004) reflect the names of the pigments that Girardoni mixes into various types of beeswax from all over the world. While the colors lean toward loud, the sculpted shapes are quiet and subtle, both whimsical and architectural. These pieces derive strength from their simple, straightforward contrast of materials: the fabricated and the found. Diptych-Orange Umber pairs a rescued, rough-hewn beam with an elegant squared column of wax that echoes the proportions of the wood, complete with a notch at the top. The two symmetrical sections are connected along the vertical, and the contrasting materials attract and adhere. For Stacked. 1-Chrome Earth Yellow, Girardoni places a long, orange wax runner atop a six-foot “balance beam.” The 4-inch-wide wax segment runs the entire length and is gently sloped at either end.
Monopod (Pair) Dioxane Mauve places two purple “huts” on stilts composed of slender pieces of pale wood. Viewers can look underneath and inside the purple forms for a full sensory immersion in chroma and aroma. The softly rounded corners and the peaks of the roofs demonstrate the artist’s dexterity with the medium; he leaves areas of rough texture intact to reveal the handcrafted nature of the work. Untitled-(4.1 Ultra Violet Dk.) follows the form of a ziggurat. This small, deep purple object sits confidently atop a slab of found wood mounted to the wall. Perhaps the most playful of the group is Line/7-Cad. Yellow Deep, a continuous, 87-inch wide encaustic rectangle with a rippled top. This undulating yellow-orange wiggle of wax literally rises to the occasion on a simple wooden table with long legs.
Inorganic pigments
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Yellow Pigments Excel in Cost & performance
Two new yellow pigments for plastic films and molded packaging boast good performance at lower cost than competing pigments. Both new products from Engelhard Corp., Appearance and Performance Technologies, Iselin, N.J., are suitable for use with polyolefins, PET, PBT, and polycarbonate. Engelhard Yellow 6226 is a red-shade yellow composed primarily of organic azo pigment and some sodium aluminum inorganic pigment. Said to “act like an inorganic pigment,” it can withstand temperatures of over 600 F. FDA approved for food contact, this pigment sells for under $10/lb, which is much lower than most FDA-approved colors. It reportedly can substitute for Pigment Yellow 191, supplied by Clariant Corp.
Engeltone Yellow 1293 is a mid-shade yellow (between red and green shades) that competes with Clariant’s PV Fast HG (Pigment Yellow 181). It is a metalized azodicarbonamide organic pigment that is FDA approved for food contact. It boasts high color strength and heat stability up to 650 F. While it does not have the lightfastness of Pigment Yellow 181, it is priced about 50% lower.
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