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1.
Evidence is presented which supports the postulate that the photobilirubins IIA and IIB are diastereoisomers in which the C-3 vinyl group has cyclized intramolecularly. The evidence comes principally from proton n.m.r. spectroscopy at 400 MHz and from chemical considerations. The cyclic structures require the E-configuration at the C-4 double bond in the precursor; this is the first structural evidence for the Z leads to E isomerization in bilirubin and supports the view that the precursor (photobilirubin IA or IB) is (4E, 15Z)-bilirubin. Brief irradiation of photobilirubin II gives bilirubin, a new compound (photobilirubin III) and unchanged starting material. The various photoisomers are discussed in terms of their inter-relationships and biological fates. 相似文献
2.
3.
N Schiering V S Stoll J S Blanchard E F Pai 《The Journal of biological chemistry》1989,264(35):21144-21145
NADH peroxidase from Streptococcus faecalis 10C1 has been crystallized from ammonium sulfate solutions using the hanging drop vapor diffusion method. Depending on pH, the crystals grew in the orthorhombic space group I222 or one of its subgroups P222 or P2(1)2(1)2 (or one of its two permutations). In both cases the unit cell axes are a = 76.6 A, b = 132.9 A, and c = 145.7 A. There are two monomers/asymmetric unit in the body-centered crystal form and four in the primitive one. The enzyme is catalytically active in the crystalline state. The crystals diffract to at least 2.5 A resolution; they are stable in the x-ray beam and hence suitable for detailed three-dimensional structure determination. 相似文献
4.
R Maraud O Vergnaud M Rashedi R Stoll 《Comptes rendus des séances de la Société de biologie et de ses filiales》1985,179(1):78-84
The capability of an embryonic testis graft to induce a male gonadal sex differentiation in genetically female chick embryos was significantly enhanced by the administration of a antiestrogenic drug (tamoxifen). This observation reinforces the view that the experimentally-induced testis differentiation depends chiefly on a inhibition of estrogen influence. 相似文献
5.
B4-2-1 cells (Lec15 cells) are Chinese hamster ovary cells deficient in mannosylphosphoryldolichol synthase activity. They synthesize the truncated lipid intermediate Man5GlcNAc2-P-P-dolichol rather than the Glc3Man9GlcNAc2-P-P-dolichol synthesized by wild-type cells. In this report we present evidence that these cells did synthesize glucosylated Man5GlcNAc2-P-P-dolichol, but this species represented only a minor fraction of the labeled oligosaccharide-lipid. On the other hand, glucosylated oligosaccharides were a major species transferred to protein in these cells, showing that in vivo, glucosylated oligosaccharides are preferentially transferred to protein. The truncated oligosaccharides found in B4-2-1 cells were removed from the protein by N-glycanase treatment, since they were resistant to both endo-beta-N-acetylglucosaminidase H and F activity. B4-2-1 cells processed the glucosylated, truncated oligosaccharides transferred to G protein of vesicular stomatitis virus, leading to infectious virus. 相似文献
6.
Retention of human skin fibroblast fatty acid modifications during maintenance culture 总被引:1,自引:0,他引:1
Arthur A. Spector Gerene M. Denning Lynn L. Stoll 《In vitro cellular & developmental biology. Plant》1980,16(11):932-940
Summary The fatty acid composition of cultured human skin fibroblasts was modified by adding either oleic or linoleic acid to the
growth medium. After the cultures became confluent, they were washed and transferred to different maintenance media in order
to determine the stability of the various fatty acyl modifications. Some changes in fatty acid composition occurred under
all conditions. When the maintenance medium was supplemented with fatty acid, the cellular neutral lipid and phospholipid
fatty acyl composition were altered markedly within 16 to 24 hr. If no supplemental fatty acid was available during the maintenance
period, however, the modified fatty acyl compositions were sufficiently retained so that appreciable differences between the
cells enriched with oleate and linoleate persisted for at least 48 to 72 hr. This considerable degree of stability occurred
when either 10% delipidized fetal bovine serum or 10% fetal bovine serum containing its inherent lipids were present in the
maintenance medium. Although the triglyceride content of the fatty acid-modified cells was quite labile, neither the cholesterol
nor phospholipid content changed appreciably during culture in any of the maintenance media. Since the fatty acid compositional
differences persisted during several days of maintenance under certain conditions, these modified cultures appear to be a
useful experimental system for assessing the effect of lipid structure on fairly long-term cellular functions.
This work was supported by Arteriosclerosis Specialized Center of Research Grant HL14230 from the National Heart, Lung and
Blood Institute, National Institutes of Health. 相似文献
7.
In a woman aged 32, who came for consultation regarding her sterility, a case of Poland's syndrome was diagnosed in view of a brachysyndactylia and a homolateral agenesia of the large pectoral. The possible connexion between her sterility and this syndrome is discussed. 相似文献
8.
R Stoll R Maraud N Faucounau 《Comptes rendus des séances de la Société de biologie et de ses filiales》1975,169(6):1466-1469
In the normal ageing rat is observed a progressive hyperplasia of the C cells. In the rat treated by an antithyroideal drug, the hyperplasia is much more important than in normal. It already appears during the treatment and grows up after its stop. This observation means that the C cells hyperplasia, which reaches later to gamma tumors production, is not due to the TSH oversecreted under the antithyroideal drug influence. 相似文献
9.
R Maraud M Audine R Stoll 《Comptes rendus des séances de la Société de biologie et de ses filiales》1975,169(4):923-927
When a chick embryo, deprived of its hypothalamo-pituitary complex by partial decapitation, is bearing a grafted hypophysis, this gland is unable to induce a normal development of the thyroid. The volume of this gland is reduced and, consequently, the fixation of iodine is decreased from the age of 16 days. Some authors think that there are no hypothalamo-pituitary correlations in the chick embryo. On the contrary, these observations lead to admit their appearance towards the end of the incubation. 相似文献
10.
Streptomyces species have a linear chromosome of approximately 8 Mb in size. Many strains also carry linear plasmids. Most of these linear elements contain terminal proteins covalently bound to the 5 ends of the DNA. Using a method for the visualisation of terminal DNA fragments in agarose gels, it was possible to see three fragments in S. rimosus and five fragments in S. avermitilis. The method was also used to clone the 298 bp BamHI fragment carrying the left end of plasmid SLP2. Analysis of the sequence showed that the end resembled other Streptomyces chromosome and plasmid ends, but there were eight palindromes (instead of seven) and a tandem duplication of a 14 bp sequence. 相似文献