Isolation of 3-(2-carboxyethyl)thymine following in vitro reaction of β-propiolactone with calf thymus DNA

3-(2-Carboxyethyl)thymine (3-CET) was synthesized from β-propiolactone (BPL) and dThd5′P at pH 9.0–9.5 via the intermediate 3-(2-carboxyethyl)thymidine-5′-monophosphoric acid (3-CEdThd5′P). 3-CEdThd5′P was converted to 3-CET by hydrolysis in 1.5 N HCl at 100°C for 2 h. The structure of 3-CET was assigned on the basis of UV spectra, electron impact (EI) and isobutane chemical ionization mass spectra and the EI mass spectrum of a trimethylsilyl derivative of 3-CET. BPL was reacted in vitro with calf thymus DNA at pH 7.5. 100 A units of BPL-reacted DNA yielded, following perchloric acid hydrolysis and preparative paper chromatography, 3 A units of 3-CET. Reaction of BPL with the phosphodiester thymidylyl-(3′-5′)thymidine gave 3-(2-carboxyethyl)thymidylyl-(3′-5′)-3-(2-carboxyethyl)thymidine (～3%). Phosphotriester formation was not detected.     

The amphipathic membrane proteins associated with gangliosides: The Paul-Bunnell antigen is one of the gangliophilic proteins

Two amphipathic protein fractions soluble in organic solvents as well as in water have been isolated from the ganglioside fraction of bovine erythrocyte membranes by successive chromatography in chloroform-methanol mixture on DEAE-Sephadex, silicic acid, and α-hydroxypropylated Sephadex G50 (LH60) columns. These two fractions contained a similar low molecular weight protein but with distinctively different amino acid composition. One of these proteins has been characterized by having a strong Paul-Bunnell antigen activity and had a binding affinity to ganglioside. A similar protein without Paul-Bunnell antigen activity was isolated as the major ganglioside-associated protein.     

Regulation of adenosine 5′-phosphosulfate sulfotransferase activity by H2S and cyst(e)ine in primary leaves of Phaseolus vulgaris L.

During chloroplast development in the primary leaves of Phaseolus vulgaris, the extractable activity of adenosine 5-phosphosulfate sulfotransferase increased ten-fold. When chloroplast development took place in air enriched with 3.5 l H₂S·l^-1 there was a decrease in adenosine 5-phosphosulfate sulfotransferase activity. Cyst(e)ine in concentrations up to 1 mM (in the external medium) did not affect the increase in adenosine 5-phosphosulfate sulfotransferase activity in intact plants. In plants with excised roots, 0.75 mM cyst(e)ine inhibited this increase. In green primary leaves, H₂S or cyst(e)ine treatment resulted in a decrease of extractable adenosine 5-phosphosulfate sulfotransferase activity. In intact plants, this effect of cyst(e)ine was observed at a concentration of 1 mM, and in plants with excised roots, 0.25 mM had a comparable effect.In developing plants, the extractable activities of O-acetyl-L-serine sulfhydrylase (EC 4.2.99.9) and ribulosebisphosphate carboxylase (EC 4.1.1.39.) were not affected by H₂S or cyst(e)ine.Abbreviations APS adenosine 5-phosphosulfate - APSSTase adenosine 5phosphosulfate sulfotransferase - BSA bovine serum albumin - DTE dithioerythritol - EDTA ethylenediaminetetra-acetic acid - OASSase O-acetyl-L-serine sulfhydrylase - PAPS adenosine 3-phosphate 5-phosphosulfate - POPOP 1,4 Di 2-(5-phenyloxazolyl)-benzene - PPO 2,5-diphenyloxazol - RubP ribulose-bisphosphate - RubPCase ribulosebiphosphate carboxylase This is no. 8 in the series Regulation of Sulfate Assimilation in Plants. The term cysteine is used when it is clear that cystine is not involved; cyst(e)ine is used for an undefined mixture of cysteine and cystine. The concentrations are expressed in all cases relative to cysteine     

Inhibition of anthocyanin formation in seedlings and flowers by the enantiomers of α-aminooxy-β-phenylpropionic acid and their N-benzyloxycarbonyl derivatives

Both enantiomers of -aminooxy--phenylpropionic acid (AOPP), potent inhibitors of L-phenylalanine ammonia-lyase, and their N-benzyloxycarbonyl (N-BOC) derivatives inhibit anthocyanin formation in developing flowers of Ipomoea tricolor Cav. and Catharanthus roseus Don. as well as in seedlings of Brassica oleracea var. caulo-rapa DC (kohlrabi) and B. oleracea var. capitata L. (red cabbage) with little interference with their normal development. Kohlrabi seedlings tolerate up to 0.3 mM L-AOPP and N-BOC-L-AOPP without a reduction of fresh weight or chlorophyll content, while anthocyanin is reduced to less than 20%.Abbreviations AOPP -aminooxy--phenylpropionic acid - N-BOC N-benzyloxycarbonyl - PAL L-phenylalanine ammonia-lyase (EC 4.3.1.5)     

The role of retinol in the initiation of sporangiophores of Phycomyces blakesleeanus

The initiation of sporangiophores of Phycomyces was analyzed under oxygen-limiting conditions. Mutants lacking -carotene have a higher oxygen threshold than the wild type depending on the residual amount of -carotene. The supersensitivity to low oxygen tension is specific for sporangiophore initiation and can be suppressed by addition of either retinal, retinol or retinol acetate to the medium. It is suggested that retinol is a natural regulator of differentiation in Phycomyces.     

Steroid delta 4-5 beta-reductase in human mammary tumors.

Steroid delta 4-5 alpha- and delta 4-5 beta-reductase activity was determined in 16 human mammary tumors and 8 DMBA-induced rat mammary tumors using a spectrophotometric assay. Steroid delta 4-5 alpha-reductase was present in all tumors investigated while delta 4-5 beta-reductase was detected in only 6 estrogen receptor negative human breast tumors and absent in all estrogen receptor positive human breast tumors as well as in all rat mammary tumors. Further support for the presence of delta 4-5 beta-reductase was established by using a dual-labelling technique consisting of incubating tumor slices with [14C] testosterone and adding [3H] etiocholanolone, [3H] testosterone and [3H]-5 alpha-dihydrotestosterone at the end of the reaction. Following extraction and chromic acid oxidation, 4-androstenedione, 5 beta-androstanedione and 5 alpha-androstanedione were isolated and purified, and the constancy of the 14C/3H ratio was used as proof of 5 alpha-reductase and 5 beta-reductase. These results were shown to be consistent with the data obtained using the spectrophotometric assay.     

Distributional patterns and an additional species of thePassiflora vitifolia complex: Amazonian species diversity due to edaphically differentiated communities

Field studies in Amazonian Peru show that thePassiflora vitifolia complex, a microcosm of many larger taxa, is concentrated in Amazonia with 4 ecologically separated species. One species is restricted to seasonally inundated forests, a second to non-inundated white sand soils, a third to non-inundated lateritic soils, and the fourth mostly to non-inundated alluvial soils. A new combination is formally proposed to recognize the white sand taxon, previously regarded as a variety, as a distinct species:P. involucrata. The importance of -diversity in maintaining high Amazonian species diversity is emphasized.     

Central neural peptides and catecholamines in spontaneous and DOCA/salt hypertension

Hypothalamic and neurophypophyseal levels of catecholamines and peptides were measured in spontaneous and deoxycorticosterone (DOCA)/salt hypertension. Catecholamines, norepinephrine, epinephrine and dopamine were measured by electrochemical detection while the peptides, vasopressin, oxytocin, luteinizing hormone-releasing hormone (LHRH), the enkephalins and somatostatin (SRIF) were measured by radioimmunoassay. Blood pressure was significantly elevated in both groups as compared to their controls. Marked changes in central neural peptides were observed in the SHR, while no differences were seen in DOCA/salt hypertension. Hypothalamic vasopressin, oxytocin, LHRH and SRIF were significantly decreased. In the posterior pituitary, enkephalins were increased twofold in the SHR. With regard to catecholamines, there was no change in hypothalamic content. However, a dramatic decrease in neurohypophyseal dopamine was observed in SHR. Plasma levels of vasopressin were significantly elevated in both types of hypertension while oxytocin was increased only in the DOCA/salt model. These result show that (1) a wide spectrum of neuroendocrine changes are associated with genetic hypertension, (2) there are CNS differences between DOCA/salt and spontaneous hypertension, and (3) central aminergic changes may be involved in th neuroendocrine alterations seen in the SHR.     

Fine structure of the ‘Wulst’ region of the domestic fowl in organotypic cultures

Summary Parts of the Wulst region of the chick embryo brain were maintained for 39 days in vitro. Processes of adjacent glial cell form zonulae occludentes and desmosomal junctions in the uppermost stratum of the cultures. Subjacent to this layer, in the neuropil, axodendritic synapses are abundant. 10–20 m below the surface the perikarya of glial cells and neurons are found. The latter form small clusters, plasma membranes of contiguous cells being directly apposed to each other. Axosomatic synapses terminate on the perikarya. Occasionally one terminal synapses on two nerve cells simultaneously. Two types of cilia arise from basal bodies in the cytoplasm of nerve cells. Type I is a slender protrusion of about 0.5 m in diameter, extending into the neuropil. On transverse sections it displays a 9 + 0 pattern of organization of paired micro tubules proximally, and an 8 + 1 configuration more distally. The length of the cilium is approximately 7 m. Type II cilia also originate in the neuronal cytoplasm. The structure of the proximal portion is identical with that of type I cilia. Toward the tip, however, the type II cilium is characterized by a bulbous enlargement which is filled with loosely folded membranes. The fine structural details of this cilium correlate closely to the outer segments of retinal photoreceptor cells during differentiation. The possible role of a light receptor in the Wulst region of birds, controlling biological rhythms, is discussed. Acknowledgements. The authors wish to thank Mrs. H. Frenk for her expert assistance in tissue culture and electron microscopic techniques