Iris bulbs

RS- P-Aminoisobutyric acid (a-methyl-P-alanine) [10569-72-9] M 103.1, m 176-178 , 178-180 , 181-182 , R -(-)- isomer [144-90-1] m 183 , [a] -21 (c 0.43, HjO), pKes,(,) 3.7, pKEst(2) 10.2. Colorless prisms from hot H O, were powdered and dried in vacuo. The purity is checked by paper chromatography (Whatman 1) using ninhydrin spray to visualise the amino acid Rp values in 95% MeOH and n-PrOH/5N HCOOH (8 2) are 0.36 and 0.50 respectively. [Kupiecki and Coon Biochem Prep 7 20 7960 Pollack J Am Chem Soc 65 1335 7943.] The R-enantiomer, isolated from iris bulbs or human urine was crystd from H2O and sublimed in vacuo [Asen et al. J Biol Chem 234 343 7959]. The RS-hydrochloride was recrystd from EtOH/Et20 m 128-129 , 130° [Bbhme et al. Chem Ber92 1258, 1260, 1261 7959]. 

Morris, C. J., J. F. Thompson, S. Asen, and F. Irreverre The isolation of y-L-glutamyl-p-aminoisobutyric acid from Iris bulbs. J. Biol. Chem. 236, 1181 (1961). 

The isolation of y-L-glutamyl-(3-alanine from Iris bulbs. J. Biol. Chem. 

Glucomannans are also obtained from seeds or roots the structure is a random arrangement of 4)-j8-Glc-(l and ->4)- -Man-(l. The ratio Glc/Man depends on the source and varies from 1 1 in Iris bulbs to 1 5 in certain gymnosperms. Konjac glucomannan has been developed mainly in Japan for food appUcations... 

Similarly-constituted glucomannans have been isolated from various species of iris seeds107 and lily bulbs,108 the polysaccharides containing D-glucose and D-mannose residues in the proportions 1 1.1 and 1 1.9, respectively. The iris-seed glucomannans also contain a small proportion of D-galactopyranose end-groups.107... 

Iris IRIP ( 30kDa monomer disulfide linked 60kDa dimer) Iris hollandica (Iridaceae) [bulb] PAG (rRNA)... 

Another popular method for distilling small quantities is to use a Buchi Kugelrohr apparatus (Fig. 11.14). The key features of this system are (i) a horizontal glass oven with an iris closure, which heats the flasks efficiently (ii) short-path distillation between a series of bulbs which can be moved horizontally in and out of the oven (iii) a motor to rotate the bulbs. The Kugelrohr can be used to distil very small quantities (< lOOmg) and can be operated at high vacuum. A simple distillation is carried out as follows ... 

Slide the end bulb into the oven and gently close the iris type seal around the coimecting joint. 

With the stopcock closed to the flask and open to atmosphere, move the levelling bulb until the level of water in the burette is at zero. f)Open the stopcock to the flask and tip the apparatus slightly to make the glass cylinderCinside the flask) fall. g)Contact of A1 with KOH soln will cause the evoln of hydrogen and movement of the level of water in the burette. The reaction lasts about 1 hour. From the volume of hydrogen evolved the amt of A1 is calcd. h)If there is any black residue in the flask, the presence of carbon is indicated and if the residue is yd or th wood iri sl is present ... 

Quinones.—Four menaquinone (139) homologues from Sarcina lutea have been identified as dihydromenaquinones-6, -7, -8, and -9. A novel quinone from bulbs and leaves of Iris is thought to be related to plastoquinone-9 (140) but to have a modified ring methylation pattern.No chemical data were reported. The distribution of ubiquinone (141) homologues in a number of Gram-negative bacteria has been surveyed.The biosynthesis of menaquinones and related quinones has been reviewed. The molecular structure and electronic properties of ubiquinone have been studied by semi-empirical molecular orbital theory. 

Y-L-Glutamyl-(/ )-P-amino-isobutyric acid (pOOH y-i.-giunhch2-( -h Iris tingitana, bulbs Iridaceae Cryst. L R (232) Iris tinaitana 6) 2 (12 )... 

Illumination and contra.st are central points in the discussion of imaging performance. Without sufficient contrast, neither the required magnification nor a maximal resolution can be obtained. A. Kohler developed optical illumination for microscopy in 1893 [8]. The main advantage of Kohler illumination is that in spite of the small filament of the light bulb, the entire area of the lamp field stop, as well as the illuminated part of the specimen, have a uniform luminance (Fig. 4). The twofold ray path of diaphragms and lenses suggests that adjustment of the condenser iris, being the illumination aperture, controls resolution, contrast, and resolution depth. This principle is also important for correct setup of the confocal microscope as well as electron microscopy. 

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