ACTA BIOLOGICA CRACOVIENSIA

PLENARY LECTURES
Xanthophyll-binding proteins: key mediators
for delivery of the macular pigment
carotenoids to the human eye
Paul S. Bernstein
Department of Ophthalmology and Visual Sciences, Moran Eye
Center, University of Utah School of Medicine, 65 Mario Capecchi
Drive, Salt Lake City, UT 84132, USA,
paul.bernstein@hsc.utah.edu
Unlike all other mammals, humans and fellow primates uniquely
concentrate the xanthophyll carotenoids lutein and zeaxanthin in
the retina of the eye in a yellow colored region known as the macula
lutea. Over the past fifteen years, our laboratory has endeavored
to elucidate the biochemical processes underlying the selective
accumulation of these macular pigment carotenoids into the
human eye. Using a combination of preparative biochemical and
molecular biological approaches, we have identified the two key
xanthophyll-binding proteins responsible for the uptake and stabilization
of the macular carotenoids, GSTP1 (dietary zeaxanthin
and non-dietary meso-zeaxanthin) and StARD3 (dietary lutein). In
this plenary lecture, I will review how the identification of these
xanthophyll-binding proteins enhances our understanding of the
role of the macular pigment carotenoids in the maintenance of
human ocular health, and I will place these binding proteins in
the larger context of our current knowledge of carotenoid transport
and deposition in diverse organisms.
REFERENCES
LI B, VACHALI P, FREDERICK JM, BERNSTEIN PS. 2011 Identification of
StARD3 as a lutein-binding protein in the macula of the primate
retina. Biochemistry 50: 2541-2549.
LI B, VACHALI P, BERNSTEIN PS. 2010. Human ocular carotenoid-binding
proteins. Photochem Photobiol Sci. 9: 1418-1425.
Are non-vitamin A active carotenoid cleavage
products metabolically active?
John W. Erdman, Jr.
Department of Food Science and Human Nutrition, University of
Illinois, 455 Bevier Hall, 905 S. Goodwin Ave, Urbana, IL,USA,
61801, jwerdman@illinois.edu
The metabolic cleavage of β-carotene has been well studied and
retinoids produced from β-carotene or other pro-vitamin A
carotenoids are known to be critical for night vision (retinal isomers)
and for growth, reproduction and other functions (retinoic
acid isomers). 9-cis-retinoic acid impacts a variety of other body
functions as a ligand for the promiscuous nuclear receptor, RXR.
An emerging area of interest are metabolic or oxidative cleavage
products of other carotenoids. As many of these compounds have
retinoid-like structures, it has been hypothesized that some may be
agonists or antagonists in various transcription systems. For example,
we have suggested that metabolic products of lycopene, the socalled
lycopenoids, may influence gene expression via nuclear
receptors such as RARs, RXRs, PPARs, LXRs, etc (Lindshield et al.,
2007). Kopec and colleagues (Kopec et al., 2011) have identified a
variety of lycopenoids in human plasma at levels near those seen
for retinoids. The recent emergence of mice lacking either of the
two important carotenoid cleavage enzymes, has provided models
to study carotenoid cleavage products more directly. This presentation
will explore studies from knock-out models and other
approaches that suggest that carotenoid metabolites as well as the
carotenoid cleavage enzyme null genotypes influence lipid metabolism
as well as steroid hormone metabolism. In addition, the effects
of tomato carotenoids on prostate carcinogenesis through a proposed
anti-androgenic mechanism will be discussed.
Vol. 53, suppl. 1, 2011
17–22 July 2011, Krakow, Poland
Supported by PHS-1-RO1CA125384 and PHS-R21AT005166.
REFERENCES
KOPEC RE, RIEDL KM, HARRISON EH, CURLEY RW JR.,
HRUSZKEWYCZ DP, CLINTON SK, SCHWARTZ SJ. 2011. Identification
and quantification of apo-lycopenals in fruits, vegetables and
human plasma. J. Ag. Food Chemistry 58: 3290-6.
LINDSHIELD BL, CANENE-ADAMS K, ERDMAN JW JR. 2007. Lycopenoids:
Are lycopene metabolites bioactive? Archives of Biochem. &
Biophys. 458: 136-140.
A journey along the pathway of carotenoid
biosynthesis: more enzymes and new routes of
interactions with plant metabolism
Joseph Hirschberg
Department of Genetics, Alexander Silberman Institute of Life
Sciences, The Hebrew University of Jerusalem, Jerusalem, 91904
Israel
In plants, carotenoids are integral components of the photosynthetic
apparatus and thus are indispensable in all green tissues.
As precursors in the production of the phytohormones abscisic
acid (ABA) and strigolactones, carotenoids serve central physiological
and developmental functions in plant adaptation to stress
conditions. In addition, they play important roles in plant reproduction
by furnishing flowers and fruit with distinct pigmentation
designed to attract animals.
Carotenoids are synthesized within the plastids from the
methylerythritol phosphate (MEP) pathway, which accounts for
the plastidial isoprenoids, though all the biosynthesis enzymes
are nuclear encoded.
We are studying carotenoid biosynthesis and its regulation
in flowers and fruit of tomato (S. lycopersicum), which has
become a model system for chromoplast-containing plants.
Over the years we have developed various genetic tools to decipher
carotenogenesis in plants by cloning and analyzing genes
that encode enzymes of the pathway. To this end, we have isolated
novel mutations in tomato that alter pigmentation of flowers
and fruit. Through characterization of these mutations we
have identified new enzymes in the carotenoid biosynthesis
pathway. Recent results demonstrated the importance of RedOx
to the biosynthesis of carotenoids and revealed links between
carotenoid biosynthesis and plastid biogenesis.
This work was supported by the Israel Science Foundation Grants
548/05 and 1685/09 by the EU-FP6 EU-SOL.
Excited-state dynamics of overlapped optically-
+ –
allowed 1Bu and optically-forbidden 1Bu or
– 3Ag vibronic levels of carotenoids: possible
roles in the light-harvesting function
Yasushi Koyama 1 , Yoshinori Kakitani 2 , Hiroyoshi Nagae 3
1Faculty of Science and Technology, Kwansei Gakuin University,
Sanda 669-1337, Japan, ykoyama@kwansei.ac.jp
2Faculty of Science and Technology, Kwansei Gakuin University,
Sanda 669-1337, Japan, kakitani@kwansei.ac.jp
3Kobe City University of Foreign Studies, Gakuen Higashimachi,
Kobe 651-2187, Japan, hf_nagae@inst.kobe-cufs.ac.jp
Pump-probe spectroscopy after selective excitation of all-trans
Cars (n = 9-13) in nonpolar solvent identified a symmetry selection
rule of diabatic electronic mixing and diabatic internal con-
+ – + –
version, i.e., '1Bu -to-1Bu is allowed but 1Bu -to-3Ag is forbidden'.
Kerr-gate fluorescence spectroscopy showed that this selection
rule breaks down, due to the symmetry degradations when the
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