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1.
M. Shirzadegan M. Christey E. D. Earle J. D. Palmer 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1989,77(1):17-25
Summary We compared Brassica campestris mitochondrial and chloroplast DNAs from whole plants and from a 2-year-old cell culture. No differences were observed in the chloroplast DNAs (cpDNAs), whereas the culture mitochondrial DNA (mtDNA) was extensively altered. Hybridization analysis revealed that the alterations are due entirely to rearrangement. At least two inversions and one large duplication are found in the culture mtDNA. The duplication element is shown to have the usual properties of a plant mtDNA high frequency recombination repeat. The culture mtDNA exists as a complex heterogeneous population of rearranged and unrearranged molecules. Some of the culture-associated rearranged molecules are present in low levels in native plant tissue and appear to have sorted out and amplified in the culture. Other mtDNA rearrangements may have occurred de novo. In addition to alterations of the main mitochondrial genome, an 11.3 kb linear mtDNA plasmid present in whole plants is absent from the culture. Contrary to findings in cultured cells of other plants, small circular mtDNA molecules were not detected in the B. campestris cell culture. 相似文献
2.
The venous system of Polypterus exhibits general asymmetry. The features that characterize the venous system of this peculiarly African fish are the possession of many blood sinuses, the segmental drainage of blood, the continuation of the posterior cardinal veins as separated vessels and the occurrence of several anastomozes between the latter.
In the absence of any recent comprehensive work on the blood system of this fish, it was thought that investigation of the circulatory system of Polypterus would be valuable. In this paper attention is drawn to Budgettapos;s (1902) original work on a larva of Polypterus senegalus. Contrary to Budgettapos;s findings it is concluded that what he called the "interrenal" vein is in fact the right posterior cardinal vein. It is also found that paired posterior cardinal veins exist in all adults. 相似文献
In the absence of any recent comprehensive work on the blood system of this fish, it was thought that investigation of the circulatory system of Polypterus would be valuable. In this paper attention is drawn to Budgettapos;s (1902) original work on a larva of Polypterus senegalus. Contrary to Budgettapos;s findings it is concluded that what he called the "interrenal" vein is in fact the right posterior cardinal vein. It is also found that paired posterior cardinal veins exist in all adults. 相似文献
3.
We report the magnetic field dependence of 1/T1 of solvent water protons and deuterons (nuclear magnetic relaxation dispersion, or NMRD, profiles) for solutions of steer lens beta L-crystallin. Such data allow the study of intermolecular protein interactions over a wide concentration range, here 1-34% vol/vol, by providing a measure of the rotational relaxation time of solute macromolecules. We conclude that, for approximately less than 5% protein, the solute particles are noncompact, with a rotationally averaged volume approximately three times that of a compact 60-kD sphere. (Earlier results for alpha-crystallin, approximately 1,000 kD, from optical and osmotic measurements (Vérétout and Tardieu, 1989. J. Mol. Biol. 205:713-728), show a similar, approximately twofold, effect). At intermediate concentrations, to approximately 20% protein, there is evidence for limited association or oligomerization, as found for the structurally related gamma II-crystallin (Koenig et al. 1990. Biophys. J. 57:461-469), to a limiting size about two-thirds that of alpha-crystallin. The difference in NMRD behavior of the three classes of crystallins is consonant with their differing osmotic properties (Vérétout and Tardieu. J. Mol. Biol. 1989, 205:713-728; Kenworthy, McIntosh, and Magid. Biophys. J. 1992. 61:A477; Tardieu et al. 1992. Eur. Biophys. J. 21:1-12). We indicate how the unusual structures and interactions of these three classes of proteins can be combined to optimize transparency and minimize colloid osmotic difficulties in eye lens. 相似文献
4.
Uniaxial strain upregulates matrix-degrading enzymes produced by human vascular smooth muscle cells 总被引:1,自引:0,他引:1
Asanuma K Magid R Johnson C Nerem RM Galis ZS 《American journal of physiology. Heart and circulatory physiology》2003,284(5):H1778-H1784
Arteries remodel in response to environmental changes. We investigated whether mechanical strain modulates production of matrix metalloproteinase (MMP)-2 and -9 by cultured vascular smooth muscle cells (SMC). MMP-2 and MMP-9 expression were tested using human saphenous vein SMC cultured on silicone membranes at rest or subjected to physiological levels (5%) of stationary or cyclical (1 Hz) uniaxial strain. Compared with control, stationary strain significantly increased MMP-2 mRNA levels at all time points, whereas cyclic strain decreased it after 48 h. Both secreted and cell-associated pro-MMP-2 levels were increased by stationary strain at all times (P < 0.01), whereas cyclic strain decreased secreted levels after 48 h (P < 0.02). MMP-9 mRNA levels and pro-MMP-9 protein were increased after 48 h of stationary stretch (P < 0.01) compared with both no strain and cyclic strain. Our study indicates that vascular SMC show a selective response to different types of strain. We suggest that local increases in stationary mechanical strain resulting from stenting, hypertension, or atherosclerosis may lead to enhanced matrix degradation by SMC. 相似文献
5.
A field study of nitrogen dynamics and spring barley growth as affected by the quality of incorporated residues from white clover and ryegrass 总被引:7,自引:0,他引:7
Hauggaard-Nielsen H. de Neergaard A. Jensen L.S. Høgh-Jensen H. Magid J. 《Plant and Soil》1998,203(1):91-101
Biofumigation refers to the suppression of soil-borne pests and pathogens by biocidal compounds released by Brassicaceous green manure and rotation crops when glucosinolates (GSLs) in their tissues are hydrolysed. We investigated the effect of environment and ontogeny on the GSL production, and thus biofumigation potential, of eight entries from five Brassica species. The environments included autumn and spring sown field plots (FA and FS) and potted plants grown under ambient conditions (PAM) or in a temperature controlled glasshouse at 20 °C/12 °C (PTC). GSL concentration was measured in the root and shoot tissue at buds-raised, flowering and maturity. Of particular interest was the suitability of the pot-grown plants for screening large numbers of brassicas for GSL production. The type of GSLs present in the tissues and their relative proportions remained relatively constant across environments and at different growth stages, with the exception of an increase in indolyl GSLs in the FS environment suspected of being induced by insect attack. Total GSL concentration generally declined from buds-raised to flowering in all environments, and was lowest at maturity. The exceptions were B. campestris, which had higher GSL concentration at flowering than at buds-raised, and the PTC environment in which most species also showed an increase at flowering. Despite GSL types and their proportions remaining relatively constant, the total GSL concentration in the root and shoot tissue of all entries varied significantly with environment (3–10-fold) and was generally ranked FS>PAM>FA>PTC. Interactions between species and environments meant that the ranking of the Brassica entries for total shoot and root GSL concentration changed with environment. However within three entries from B. napus, the ranking was consistent across the environments. The added effect of environment on phenological development and biomass production further influenced GSL production (the product of GSL concentration and biomass) on a ground area basis. The results suggest that glasshouse environments can be used to determine the types and proportions of GSLs present, and to rank entries within, but not between species for the total concentration in the tissues. However the influence of the environment on both GSL concentration and biomass production suggests that an accurate estimate of GSL production on a ground area basis to assess biofumigation potential will require measurement in the target environment. 相似文献
6.
Haba H Lavaud C Harkat H Alabdul Magid A Marcourt L Benkhaled M 《Phytochemistry》2007,68(9):1255-1260
Two new compounds with tigliane and cycloartane skeletons: 4,12-dideoxy(4alpha)phorbol-13-hexadecanoate (1) and 24-methylenecycloartane-3,28-diol (2), respectively, in addition of four known diterpenoids and 13 triterpenoids: 3-benzoyloxy-5,15-diacetoxy-9,14-dioxojatropha-6(17),11-diene (4), ent-abieta-8(14),13(15)-dien-16,12-olide (5), ent-8alpha,14alpha-epoxyabieta-11,13(15)-dien-16,12-olide (6), ent-3-hydroxyatis-16(17)-ene-2,14-dione (7), 3beta-hydroxytaraxer-14-en-28-oic acid (8), beta-sitosteryl-3beta-glucopyranoside-6'-O-palmitate (9), multiflorenyl acetate (10), multiflorenyl palmitate (11), peplusol (12), 24-methylenecycloartanol (3), lanosterol (13), euferol (14), butyrospermol (15), cycloartenol (16), obtusifoliol (17), cycloeucalenol (18) and beta-sitosterol (19), were isolated from the roots of Euphorbia guyoniana. Their structures were established on the basis of physical and spectroscopic analysis, including 1D and 2D homo- and heteronuclear NMR experiments (COSY, HSQC, HMBC and NOESY) and by comparison with the literature data. 相似文献
7.
Ghidu VP Ilies MA Cullen T Pollet R Abou-Gharbia M 《Bioorganic & medicinal chemistry letters》2011,21(1):259-261
CL285032 is an anxiolytic compound currently under investigation as a possible treatment for canine noise phobia associated anxiety. A robust scale-up and manufacturing process is essential for the development and marketability of the drug. The current synthetic route, although reliable, requires seven steps and has a low overall yield (18%), leaving opportunity for improvement. We are presenting an efficient alternative approach toward the synthesis of CL285032 and the results thereof. 相似文献
8.
Alabdul Magid A Voutquenne-Nazabadioko L Renimel I Harakat D Moretti C Lavaud C 《Phytochemistry》2006,67(19):2096-2102
Five triterpenoid saponins, caryocarosides II-22 (3), III-22 (4), II-23 (5), III-23 (6), and II-24 (7), have been isolated from the methanol extract of the stem bark of Caryocar villosum, along with two known saponins (1-2). The seven saponins are glucuronides of hederagenin (II) or bayogenin (III). Caryocaroside II-24 (7) is an unusual galloyl ester saponin acylated on the sugar chain attached to C-28, the 3-O-alpha-L-rhamnopyranosyl-(1-->3)-beta-D-galactopyranosyl-(1-->3)-beta-D-glucuronopyranosyl hederagenin-28-O-[2-O-galloyl-beta-D-glucopyranosyl] ester. The structures of the saponins were established on the basis of extensive NMR ((13)C, (1)H, COSY, TOCSY, HSQC, HMBC and ROESY) and ESI-MS studies. The cytotoxic activity of saponins 2 and 3 was evaluated in vitro against human keratinocytes. The DOPA-oxidase inhibition and the lipolytic activities were evaluated ex vivo using an explant of human adipose tissue. 相似文献
9.
Magid Jakob Henriksen Ole Thorup-Kristensen Kristian Mueller Torsten 《Plant and Soil》2001,228(1):73-82
We examined the decomposition of Medicago lupulina, Melilotus alba and Poa pratensis at 3, 9, and 25 °C during 4 weeks. There was a strong temperature effect on the rate of CO2 evolution, and thus the extent of energy exhaustion from the added substrates. However, there was no concomitant retardation of N mineralisation at low temperatures. In the analysis of variance of mineralized N the residue type gave a 10 times larger contribution to the regression than the temperature (T), whereas for CO2 evolution residue type and temperature were equally important contributors. This indicates that although the temperature has a statistically significant effect on N-mineralisation it is substantially less than compared with the effect on carbon mineralisation in the materials examined. The retardation of carbon mineralisation was least strong in Melilotus alba that had a relatively low cellulose content, and a higher content of low molecular compounds. Though more research will be necessary to consolidate and explain this phenomena, it is likely that an important factor is a decrease in the bioavailability of C-rich polymers at low temperatures, and thus a preferential utilization of N-rich low molecular substances. Nitrification was not effectively deterred at 3 °C. Thus, in terms of management, it is pertinent to reconsider the timing of green manure and catch crop incorporation in cool temperate climate regions, since the rapid release of nitrogen, coupled with the relatively undeterred nitrification may result in a high N leaching risk by early incorporation, but a low risk for N immobilization at late incorporation, if N rich residues are used. 相似文献
10.
Benjamin E. Blass Pravin Iyer Magid Abou-Gharbia Wayne E. Childers John C. Gordon Mercy Ramanjulu George Morton Premkumar Arumugam Joshodeep Boruwa John Ellingboe Sayan Mitra Rajashekar Reddy Nimmareddy Shalini Paliwal Jamallamudi Rajasekhar Savithiri Shivakumar Pratima Srivastava Raghuram S. Tangirala Konda Venkataramanaiah L. Krishnakanth Reddy 《Bioorganic & medicinal chemistry letters》2018,28(13):2270-2274
The synthesis of steroid hormones is critical to human physiology and improper regulation of either the synthesis of these key molecules or activation of the associated receptors can lead to disease states. This has led to intense interest in developing compounds capable of modulating the synthesis of steroid hormones. Compounds capable of inhibiting Cyp19 (Aromatase), a key enzyme in the synthesis of estrogens, have been successfully employed as breast cancer therapies, while inhibitors of Cyp17 (17α-hydroxylase-17,20-lyase), a key enzyme in the synthesis of glucocorticoids, mineralocorticoids and steroidal sex hormones, are a key component of prostate cancer therapy. Inhibition of CYP17 has also been suggested as a possible target for the treatment of Cushing Syndrome and Metabolic Syndrome. We have identified two novel series of stilbene based CYP17 inhibitors and demonstrated that exemplary compounds in these series have pharmacokinetic properties consistent with orally delivered drugs. These findings suggest that compounds in these classes may be useful for the treatment of diseases and conditions associated with improper regulation of glucocorticoids synthesis and glucocorticoids receptor activation. 相似文献