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1.
The low ethylene yield in a cell-free ethylene-forming system from olive tree leaves ( Olea europaea L. cv. Picual) was investigated. During the incubation, 1-aminocyclopropane-1-carboxylic acid (ACC) was extensively transformed into 3-hydroxypropyl amide (HPA). Enzyme extract, Mn2+ and oxygen are responsible for this reaction. Horseradish peroxidase (EC 1.11.1.7) can substitute for the enzyme extract in this reaction. HPA formation could be one reason for the poor in vitro conversion efficiency of ACC to ethylene. 相似文献
2.
Summary
Coleus blumei cells were immobilized in a column reactor packed withLuffa cylindrica pieces. Medium was fed from the top of the column using a spray system and cells maintained high viability for 52 days. Cell
growth was slower but rosmarinic acid production was better compared to immobilized cells in the shake flasks. 相似文献
3.
Expression of a maize proteinase inhibitor gene is induced in response to wounding and fungal infection: systemic wound-response of a monocot gene 总被引:22,自引:0,他引:22
Maria José Cordero Dora Raventós Blanca San Segundo 《The Plant journal : for cell and molecular biology》1994,6(2):141-150
The isolation and characterization of cDNA and genomic clones encoding a proteinase inhibitor protein (MPI) in maize is reported. Accumulation of the MPI mRNA is induced in response to fungal infection in germinating maize embryos. The expression pattern of the MPI gene, in healthy and fungal infected maize tissues, was examined and compared with the expression pattern of a gene that codes for a pathogenesis-related protein (the PRms protein) from maize. These two genes are induced by fungal infection, however different signals trigger their activation. Accumulation of the proteinase inhibitor mRNA is more a consequence of the wound produced by the penetration and colonization of the host tissues by the pathogen, than the result of a direct molecular recognition of the pathogen by the plant, as is the case for the induction of the PRms gene. Wounding, or treatment with abscisic acid or methyl jasmonate, stimulate MPI mRNA accumulation, but not PRms mRNA accumulation. Local and systemic induction of the MPI gene expression in response to wounding occurs in maize plants. To the authors' knowledge, this is the first example of a gene from a monocotyledonous species that clearly shows a systemic wound response. The possible functional implications for the existence of different signal transduction pathways that simultaneously activate a battery of defense mechanisms against potential pathogens are discussed. 相似文献
4.
Mauricio Goihman-Yahr Leo Pine Maria Cecilia Albornoz Luis Yarzabal Maria Helena De Gomez Blanca San Martin Ana Ocanto Tulio Molina Jacinto Convit 《Mycopathologia》1980,71(2):73-83
Mild sonication was used to obtain single cell suspensions of Paracoccidioides brasiliensis. These cells were intact by microscopic criteria. Direct cell counts in a given inoculum and colony formation on various media were used to determine plating efficiency. Sonicated and nonsonicated cell suspensions were used to study plating efficiency and to estimate viability by means of vital dyes. Methylene blue, Erythrosin B, and Janus green were unreliable when used with P. brasiliensis, but vital dyes were accurate when tested with Candida albicans.Acridine orange gave more meaningful results of viability. Estimates of viability, however, changed significantly as a result of relatively minor alterations in the composition of the suspending medium.In initial experiments, the plating efficiency of P. brasiliensis was dismally low. It descended abruptly with increasing dilution of inoculum. Efficiency was much improved if horse serum was added to brain heart infusion plates or if glucose glycine yeast extract (GGY) plates were incubated at room temperature and mycelial colonies were counted. With the technique we report, current plating efficiency of sonicated suspensions is of the order of 25 %. Our results and procedures have an important bearing upon those studies concerned with in vitro killing of P. brasiliensis in suspensions or with isolating this fungus from clinical or environmental specimens. 相似文献
5.
Raúl Alva J. Antonio Lugo-R Eduardo Arzt Jorge Cerbón Blanca E. Rivera Mireya Toro Sergio Estrada-O 《Journal of bioenergetics and biomembranes》1992,24(1):125-129
Nigericin is a monocarboxylic polyether molecule described as a mobile K+ ionophore unable to transport Li+ and Cs+ across natural or artificial membranes. This paper shows that the ion carrier molecule forms complexes of equivalent energy demands with Li+, Cs+, Na+, Rb+, and K+. This is in accordance with the similar values of the complex stability constants obtained from nigericin with the five alkali metal cations assayed. On the other hand, nigericinalkali metal cation binding isotherms show faster rates for Li+ and Cs+ than for Na+, K+, and Rb+, in conditions where the carboxylic proton does not dissociate. Furthermore, proton NMR spectra of nigericin-Li+ and nigericin-Cs+ complexes show wide broadenings, suggesting strong cation interaction with the ionophore; in contrast, the complexes with Na+, K+, and Rb+ show only clear-cut chemical shifts. These latter results support the view that nigericin forms highly stable complexes with Li+ and Cs+ and contribute to the explanation for the inability of this ionophore to transport the former cations in conditions where it catalyzes a fast transport of K+>Rb+>Na+.Part of the results of this paper were presented at the 14th International Congress of Biochemistry in Prague, Czechoslovakia. 相似文献
6.
Isolation and re-association of the subunits from the pro-(carboxypeptidase A)–pro-(proteinase E) binary complex from pig pancreas 下载免费PDF全文
Josep Vendrell Francesc X. Aviles Blanca San Segundo Claudi M. Cuchillo 《The Biochemical journal》1982,205(2):449-452
The component subunits of the pro-(carboxypeptidase A)–pro-(proteinase E) binary complex from pig pancreas were separated with a high recovery (80–95%) of their original potential activity. The isolated subunits and the reconstituted complex have properties similar to those of the corresponding natural species. The tryptic activation course of the pro-(carboxypeptidase A) subunit is substantially modified when bound to pro-(proteinase E), whereas the activation of pro-(proteinase E) is not dependent on this association. 相似文献
7.
I. Lamas‐Toranzo A. Martínez‐Moro E. OCallaghan G. Milln‐Blanca J.M. Snchez P. Lonergan P. Bermejo‐lvarez 《Molecular reproduction and development》2020,87(5):542-549
Targeted knock‐in (KI) can be achieved in embryos by clustered regularly interspaced short palindromic repeats (CRISPR)‐assisted homology directed repair (HDR). However, HDR efficiency is constrained by the competition of nonhomologous end joining. The objective of this study was to explore whether CRISPR‐assisted targeted KI rates can be improved in bovine embryos by exposure to the HDR enhancer RS‐1. In vitro produced zygotes were injected with CRISPR components (300 ng/µl Cas9 messenger RNA and 100 ng/µl single guide RNA against a noncoding region) and a single‐stranded DNA (ssDNA) repair template (100 ng/µl). ssDNA template contained a 6 bp XbaI site insert, allowing targeted KI detection by restriction analysis, flanked by 50 bp homology arms. Following microinjection, zygotes were exposed to 0, 3.75, or 7.5 µM RS‐1 for 24 hr. No differences were noted between groups in terms of development or genome edition rates. However, targeted KI rates were doubled in the group exposed to 7.5 µM RS‐1 compared to the others (52.8% vs. 25% and 23.1%, for 7.5, 0, and 3.75 µM, respectively). In conclusion, transient exposure to 7.5 µM RS‐1 enhances targeted KI rates resulting in approximately half of the embryos containing the intended mutation, hence allowing direct KI generation in embryos. 相似文献
8.
Eileen Fahrenkamp Blanca Algarra Luca Jovine 《Molecular reproduction and development》2020,87(3):326-340
Fertilization by more than one sperm causes polyploidy, a condition that is generally lethal to the embryo in the majority of animal species. To prevent this occurrence, eggs have developed a series of mechanisms that block polyspermy at the level of the plasma membrane or their extracellular coat. In this review, we first introduce the mammalian egg coat, the zona pellucida (ZP), and summarize what is currently known about its composition, structure, and biological functions. We then describe how this specialized extracellular matrix is modified by the contents of cortical granules (CG), secretory organelles that are exocytosed by the egg after gamete fusion. This process releases proteases, glycosidases, lectins and zinc onto the ZP, resulting in a series of changes in the properties of the egg coat that are collectively referred to as hardening. By drawing parallels with comparable modifications of the vitelline envelope of nonmammalian eggs, we discuss how CG‐dependent modifications of the ZP are thought to contribute to the block to polyspermy. Moreover, we argue for the importance of obtaining more information on the architecture of the ZP, as well as systematically investigating the many facets of ZP hardening. 相似文献
9.
Blanca Domenech‐Ximenos Victor Cuba Pepus Daunis‐i‐Estadella Santiago Thi‐Henestrosa Francisco Jaldo Carles Biarnes Xavier Molina Gemma Xifra Wifredo Ricart Anton Bardera Imma Boada Marco Essig Salvador Pedraza Massimo Federici Jos Manuel Fernndez‐Real Josep Puig 《Obesity (Silver Spring, Md.)》2020,28(9):1663-1670
10.
Ana Aranda Paloma Campo Arantxa Palacin Inmaculada Do?a Cristina Gomez-Casado Luisa Galindo Araceli Díaz-Perales Miguel Blanca 《PloS one》2013,8(1)