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81.
The chemical composition of two plasma membrane fractions from epimastigote forms of Trypanosoma cruzi is reported. Fraction M, a preparation obtained by conventional methods of cell fractionation is composed of 31% proteins, 34% lipids, 16% carbohydrates and 3% of the lipopeptidophosphoglycan. Phospholipids and sterols account for 7.5 and 9%, respectively, of the total mass. Phosphatidylethanolamine is the major phospholipid in fraction M, representing 45% of the total membrane phospholipids. The other fraction, fraction V (vesicles), was obtained by treatment of the cell with a vesiculating agent. This fraction contains 42% lipids, 20% carbohydrates, 13% proteins and 21% of the lipopeptidophosphoglycan. Phospholipids and sterols make up 17 and 8%, respectively, of the total mass of this fraction. Phosphatidylcholine and phosphatidylethanolamine are the main phospholipids found in fraction V. Phosphonolipids and sialic acid have not been detected in either membrane fraction. Sodium dodecyl sulphate polyacrylamide gel electrophoretic analysis show that the glycoproteins ABC and the lipopeptidophosphoglycan are 50- and 10-times more concentrated, respectively, in fractions V and M than in the whole cell homogenate. The high molar sterol/phospholipid ratio found in fraction M suggests that this fraction is less fluid than fraction V, perhaps reflecting a migration of certain membrane components in the presence of the vesiculating agent. Hence, fraction M is, probably, more representative of the epimastigote plasma membrane as a whole than fraction V. 相似文献
82.
Giuseppe Bellucci Giancarlo Berti Maria Ferretti Franco Marioni Franca Re 《Biochemical and biophysical research communications》1981,102(3):838-844
The hydrolysis of (±)--3-bromo-1,2-epoxycyclohexane in the presence of rabbit liver microsomes was investigated, and found to yield, beside -3-bromocyclohexane--1,-2-diol, 2,3-epoxycyclohexanol. It was demonstrated that the latter compound was the only product of the enzymatic reaction, whereas the diol resulted from a non enzymatic hydration in the reaction medium. These data provide the first direct proof for a general base catalysis in the enzymatic epoxide hydration, previously hypothesized on the basis of several lines of indirect evidence, and disprove alternative mechanisms involving protonation of the oxirane oxygen. 相似文献
83.
84.
85.
Paolo Perticone Caterina Tanzarella Fabrizio Palitti Ruggero Ricordy Pietro Di Chiara Giuseppe Di Pietro Franco Spirito Gianpietro Diana Rosella De Salvia Marco Rizzoni 《Chromosoma》1976,56(3):243-248
The composition in segregated haploid sets of paternal and maternal chromosomes has been studied in order to verify whether their composition is uniparental of mixed, fixed or variable. Primary cultures where prepared using kidneys from hybrids of strains of Mus musculus in which the parental chromosomes are distinguishable; the maternal set consists of 20 teleocentric chromosomes, the paternal set of 9 metacentric chromosomes, derived by Robertsonian fusion and 2 telocentrics. Applying Seabright's banding technique, an analysis of segregated haploid and diploid cells, which have originated spontaneously through polyploidisation-segregation processes was carried out. It was concluded that the haploid sets have a variable composition of paternal and maternal chromosomes. 相似文献
86.
Franco Bellesia Romano Grandi Alessandro Marchesini Ugo M. Pagnoni Roberto Trave 《Phytochemistry》1975,14(8):1737-1740
Ageratriol is biosynthesized from agerol through a diepoxide derivative. Mevalonic acid incorporation revealed that the formation of the isopropenylic double bond is not stereospecific. 相似文献
87.
PCR-based genomic fingerprinting by use of enterobacterial repetitive intergenic consensus primers (ERIC-PCR) was evaluated
for its use in fingerprinting DNA of mixed Gram-negative bacterial strains and BIOLOG Gram-negative (GN) microplate substrate
communities. ERIC-PCR fingerprints of six different pure bacterial strains and a combined mixture of the strains were compared
with fingerprints obtained by two more established methods: amplified ribosomal DNA restriction analysis (ARDRA) and random
amplified polymorphic DNA analysis (RAPD-PCR). The ERIC-PCR fingerprint of the mixed strains was highly reproducible and was
more species-specific and representative of the individual strain fingerprints than the ARDRA and RAPD-PCR fingerprints, respectively.
ERIC-PCR fingerprinting of model and rhizosphere BIOLOG GN substrate communities also provided clearly distinguishable fingerprints.
Results of this study suggest that ERIC-PCR represents a rapid and highly discriminating method for fingerprinting DNA of
mixed Gram-negative bacterial strains and BIOLOG GN substrate communities.
Received: 11 September 1998 / Accepted: 29 October 1998 相似文献
88.
Studer B Boller B Bauer E Posselt UK Widmer F Kölliker R 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2007,115(1):9-17
Crown rust, caused by Puccinia coronata f. sp. lolii, is one of the most important diseases of temperate forage grasses, such as ryegrasses (Lolium spp.), affecting yield and nutritional quality. Therefore, resistance to crown rust is a major goal in ryegrass breeding
programmes. In a two-way pseudo-testcross population consisting of 306 Lolium multiflorum individuals, multisite field evaluations as well as alternative methods based on artificial inoculation with natural inoculate
in controlled environments were used to identify QTLs controlling resistance to crown rust. Disease scores obtained from glasshouse
and leaf segment test (LST) evaluations were highly correlated with scores from a multisite field assessment (r = 0.66 and 0.79, P < 0.01, respectively) and thus confirmed suitability of these methods for crown rust investigations. Moreover, QTL mapping
based on a linkage map consisting of 368 amplified fragment length polymorphism (AFLP) and simple sequence repeat (SSR) markers
revealed similar results across different phenotyping methods. Two major QTLs were consistently detected on linkage group
(LG) 1 and LG 2, explaining up to 56% of total phenotypic variance (V
p). Nevertheless, differences between position and magnitude of QTLs were observed among individual field locations and suggested
the existence of specific local pathogen populations. The present study not only compared QTL results among crown rust evaluation
methods and environments, but also identified molecular markers closely linked to previously undescribed QTLs for crown rust
resistance in Italian ryegrass with the potential to be applied in marker-assisted forage crop breeding.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
89.
Isabel C.M. Fensterseifer Mário R. Felício Eliane S.F. Alves Marlon H. Cardoso Marcelo D.T. Torres Carolina O. Matos Osmar N. Silva Timothy K. Lu Maurício V. Freire Natan C. Neves Sónia Gonçalves Luciano M. Lião Nuno C. Santos William F. Porto Cesar de la Fuente-Nunez Octavio L. Franco 《生物化学与生物物理学报:生物膜》2019,1861(7):1375-1387
Infections caused by Gram-negative bacteria, Escherichia coli and Pseudomonas aeruginosa foremost among them, constitute a major worldwide health problem. Bioinformatics methodologies are being used to rationally design new antimicrobial peptides, a potential alternative for treating these infections. One of the algorithms used to develop antimicrobial peptides is the Joker, which was used to design the peptide PaDBS1R6. This study evaluates the antibacterial activities of PaDBS1R6 in vitro and in vivo, characterizes the peptide interaction to target membranes, and investigates the PaDBS1R6 structure in contact with mimetic vesicles. Moreover, we demonstrate that PaDBS1R6 exhibits selective antimicrobial activity against Gram-negative bacteria. In the presence of negatively charged and zwitterionic lipids the structural arrangement of PaDBS1R6 transits from random coil to α-helix, as characterized by circular dichroism. The tertiary structure of PaDBS1R6 was determined by NMR in zwitterionic dodecylphosphocholine (DPC) micelles. In conclusion, PaDBS1R6 is a candidate for the treatment of nosocomial infections caused by Gram-negative bacteria, as template for producing other antimicrobial agents. 相似文献
90.
Franco Chimenti Daniela Secci Adriana Bolasco Paola Chimenti Arianna Granese Simone Carradori Elias Maccioni M. Cristina Cardia Matilde Yáñez Francisco Orallo Stefano Alcaro Francesco Ortuso Roberto Cirilli Rosella Ferretti Simona Distinto Johannes Kirchmair Thierry Langer 《Bioorganic & medicinal chemistry》2010,18(14):5063-5070
The present study reports on synthesis in high yields (70–99%), HPLC enantioseparation, inhibitory activity against human monoamino oxidases, and molecular modeling including 3D-QSAR studies, of a large series of (4-aryl-thiazol-2-yl)hydrazones (1–45). Most of the synthesized compounds proved to be potent and selective inhibitors of hMAO-B isoform in the micromolar or nanomolar range, thus demonstrating that hydrazothiazole could be considered a good pharmacophore to design new hMAO-B inhibitors. Due to the presence in some derivatives of a chiral center, we also performed a semipreparative chromatographic enantioseparation of these compounds obtained by a stereoconservative pattern. The separated enantiomers were submitted to in vitro biological evaluation to point out the stereorecognition of the active site of the enzyme towards these structures. Finally, a 3D-QSAR study was carried out using Comparative Molecular Field Analysis (CoMFA), aiming to deduce rational guidelines for the further structural modification of these lead compounds. 相似文献