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1、COMPLEMENTARY CHROMATIC ADAPTATIONIN A FILAMENTOUS BLUE-GREEN ALGAALLEN BENNETT and LAWRENCE BOGORADFrom The Biological Laboratories, Harvard University, Cambridge, Massachusetts 02138. 1)r. Bennetts present address is the Biology Department, Brookhaven National Laboratory, Upton,Long Island, New Yo
2、rk11978.ABSTRACTFluorescent and red light environments generate greatly different patterns of pigmentation and morphology inFremyella diplosiphon.Most strikingly, red-illuminated cultures contain no measurable C-phycoerythrin and have a mean filament length about 10 times shorter than fluorescent-il
3、luminated cultures. C-phycoerythrin behaves as a photoinducible con- stituent of this alga. Spectrophotometric and immunochemical procedures were devised so that C-phycoerythrin metabolism could be studied quantitatively with14C-phenylala- nine pulse-chased cultures. Transfer of red-illuminated cult
4、ures to fluorescent light initiates C-phycoerythrin production by essentiallyde novosynthesis. C-phycoerythrin is not de- graded to any significant extent in cultures continuously illuminated with fluorescent light. Transfer of fluorescent-illuminated cultures to red light causes an abrupt cessation
5、 of C-phycoerythrin synthesis. The C-phycoerythrin content of cultures adapting to red lightdecreases and subsequently becomes constant. Loss of C-phycoerythrin is not brought about by metabolic degradation, but rather by a decrease in mean filament length which is effected by transcellular breakage
6、 . In this experimental system, light influences intra- cellular C-phycoerythrin levels by regulating the rate of synthesis of the chromoprotein.INTRODUCTIONEnvironmental conditions exert a strong influence upon the pigment composition of many algae (Halldal, 1970). Complementary chromatic adap- tat
7、ion is a spectacular response of some blue-green and red algae to alterations in the energy distribu- tion in the visible light environment. As a conse- quence of this phenomenon, the pigment which absorbs the incident wavelengths of light most strongly becomes predominant. Gaidukov (1902)first desc
8、ribed complementary chromatic adapta-tion in blue-green algae. He observed thatOscilla-toria sanctaassumed a red coloration after growthunder green light and a blue-green tint after growth under orange light. Gaidukov (1902)ascribed these color variations to the synthesis ofdifferent kinds of pigmen
9、ts. Kylin (1912) and Boresch (1919, 1921), further, correctly perceived that such color changes in blue-green algae are primarily a specific consequence of alterations in the relative proportions of the red and blue phyco- biliprotein constituents. The demonstration that phycobiliproteins function a
10、s accessory pigments (Engelmann, 1883; Emerson and Lewis, 1942; Haxo and Blinks, 1950; Duysens, 1951; French andYoung, 1952) provided a rationale for complemen-tary chromatic adaptation: alterations in the levelsof these chromoproteins permitted maximal utili-zation of the available light energy for
11、 photosyn-thetic purposes. The principal concern of the work reported inTHE JOURNAL OF CELL BIOLOGYVOLUME 58, 1973pages419-435419this communication was to define, in broad meta- bolic terms, how light influences C-phycoerythrin (PE)metabolism during complementary chro-matic adaptation inFremyella di
12、plosiphon.The netintracellular levels of individual phycobiliproteins may decrease during complementary chromatic adaptation in growing blue-green algae. Such light-induced decreases could be brought abouteither by acceleration in the rate of phycobilipro- tein degradationorby deceleration in the ra
13、te of phycobiliproteinsynthesisanddilutionwith growth. It is impossible a priori to distinguish be-tween these alternatives. Experimentally, “syn- thesis-versus-degradation“ problems have been most readily approached with inducible cellularconstituents, such as 0-galactosidase inEscherichiacoli(see
14、Hogness et al., 1955). The levels of in- ducible components are very low in the absence of appropriate enviror4nental stimuli. Spectral re- sponsecurvesforcomplementarychromatic adaptation inTolypothrix tenuis(Fujita and Hattori, 1962) indicated that quanta with wavelengths greater than about 585 nm
15、 do not stimulate PEsynthesis. This suggested that it might be possibleto utilize restricted conditions of illumination togive PE the status of an inducible cell constituent during complementary chromatic adaptation. The filamentous blue-green algaF. diplosiphonwas selected for these experiments bec
16、ause it shows striking complementary chromatic adaptation andbecause its trichomes, unlike those ofT. tenuisand many other filamentous blue-green algae, do not clump together into large masses or adhere to thesides of the culture flasks. This latter feature greatly reduces the variability between replicate samples obtained from liquid cultures. Numerous differences in pigmentation and morphology exist betweenF. diplosiphonadapted to fluorescent and to red light . The kinetics of the chang
