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51.
Giovanni Fontana Roberto De Bernardi Federico Ferro Anita Gemignani Maurizio Raiteri 《Journal of neurochemistry》1996,66(1):161-168
Abstract: l -Glutamate, NMDA, dl -α-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA), and kainate (KA) increased the release of somatostatin-like immunoreactivity (SRIF-LI) from primary cultures of rat hippocampal neurons. In Mg2+ -containing medium, the maximal effects (reached at ∼100 µ M ) amounted to 737% (KA), 722% (glutamate), 488% (NMDA), and 374% (AMPA); the apparent affinities were 22 µ M (AMPA), 39 µ M (glutamate), 41 µ M (KA), and 70 µ M (NMDA). The metabotropic receptor agonist trans -1-aminocyclopentane-1,3-dicarboxylate did not affect SRIF-LI release. The release evoked by glutamate (100 µ M ) was abolished by 10 µ M dizocilpine (MK-801) plus 30 µ M 1-aminophenyl-4-methyl-7,8-methylenedioxy-5 H -2,3-benzodiazepine (GYKI 52466). Moreover, the maximal effect of glutamate was mimicked by a mixture of NMDA + AMPA. The release elicited by NMDA was sensitive to MK-801 but insensitive to GYKI 52466. The AMPA- and KA-evoked releases were blocked by 6,7-dinitroquinoxaline-2,3-dione (DNQX) or by GYKI 52466 but were insensitive to MK-801. The release of SRIF-LI elicited by all four agonists was Ca2+ dependent, whereas only the NMDA-evoked release was prevented by tetrodotoxin. Removal of Mg2+ caused increase of basal SRIF-LI release, an effect abolished by MK-801. Thus, glutamate can stimulate somatostatin release through ionotropic NMDA and AMPA/KA receptors. Receptors of the KA type (AMPA insensitive) or metabotropic receptors appear not to be involved. 相似文献
52.
Cormaci Mario Furnari Giovanni Scammacca Blasco Alongi Giuseppina 《Hydrobiologia》1996,326(1):267-272
Results of a seasonal study on biomass in an infralittoral population of Iridaea cordata from Terra Nova Bay (Ross Sea, Antarctica) are reported. Thalli were collected during the IX Italian Antarctic Expedition (austral summer 1993–94). The population studied is that living at depths of 4 to 6 m, where the highest density of plants occurred. The highest value of biomass (wet weight 3440 g m–2) was found at the beginning of summer. In that period 72.5% of biomass was from 128 specimens belonging to weight classes 8 (>16 to 32 g) to 10 (>64 g), corresponding to 13.4% of the population in numbers. Small (<1 g) and medium (1 to 8 g) specimens provided the remaining biomass of 5% and 22.5%, respectively. During the month of January, the number of heavy specimens decreased. At the end of that month biomass reached a minimum of 2225 g m–2. In February the biomass increased to 3169 g m –2, 72% of which was from 120 specimens belonging to weight classes 7 (>8 to 16 g) to 9 (>32 to 64 g), which numerically represented 18.5% of the population. Data showed that biomass depended mainly on the presence of large heavy specimens, even though they were always few in number. Moreover, the occurrence of such large thalli at the beginning of summer suggests that Iridaea cordata continues to grow during the long antarctic winter. 相似文献
53.
The contribution of the alternative pathway to the respiration of suspension-cultured pear ( Pyrus communis cv. Passa Crasanne) cells was enhanced, often severalfold, within 2 to 4 days following the addition of cycloheximide, actinomycin D, or 2-(4-methyl-2,6-dinitroanalino)- N -methyl propionamide (D-MDMP). Concomitant inhibition of cellular protein synthesis by cycloheximide and actinomycin D was transient and incomplete. However, inhibition by D-MDMP was virtually complete (>97%) and persisted over several days. [35 S]-labelling and polyacrylamide gel separation indicated that cycloheximide precluded the appearance of discernable new proteins in mitochondria. Probes with monoclonal antibodies revealed a conservation of alternative oxidase protein levels in the mitochondria of inhibitor-treated cells. The data, appraised within the complexities of cell-culture dynamics, lead to the conclusion that the observed increases in capacity for cyanide-resistant respiration are the consequence, likely indirect, of inhibited protein synthesis with resultant retention and activation of constitutive alternative oxidase. 相似文献
54.
Fine mapping of the Autosomal Dominant Split Hand/Split Foot Locus on Chromosome 7, Band q21.3-q22.1 总被引:6,自引:3,他引:3
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Stephen W. Scherer Parvoneh Poorkaj Todd Allen Julia Kim Dorrit Geshuri Mark Nunes Sylvia Soder Karen Stephens Roberta A. Pagon Michael A. Patton Mary Anne Berg Tim Donlon Horacio Rivera R. A. Pfeiffer Kenji Naritomi Helen Hughes Maurizio Genuardi Fiorella Gurrieri Giovanni Neri Everett Lovrein Ellen Magenis Lap-Chee Tsui James P. Evans 《American journal of human genetics》1994,55(1):12-20
Split hand/split foot (SHFD) is a human developmental defect characterized by missing digits, fusion of remaining digits, and a deep median cleft in the hands and feet. Cytogenetic studies of deletions and translocations associated with this disorder have indicated that an autosomal dominant split hand/split foot locus (gene SHFD1) maps to 7q21-q22. To characterize the SHFD1 locus, somatic cell hybrid lines were constructed from cytogenetically abnormal individuals with SHFD. Molecular analysis resulted in the localization of 93 DNA markers to one of 10 intervals surrounding the SHFD1 locus. The translocation breakpoints in four SHFD patients were encompassed by the smallest region of overlap among the SHFD-associated deletions. The order of DNA markers in the SHFD1 critical region has been defined as PON–D7S812–SHFD1–D7S811–ASNS. One DNA marker, D7S811, detected altered restriction enzyme fragments in three patients with translocations when examined by pulsed-field gel electro-phoresis (PFGE). These data map SHFD1, a gene that is crucial for human limb differentiation, to a small interval in the q21.3-q22.1 region of human chromosome 7. 相似文献
55.
In the former part of the review the principal available data aboutHox genes, their molecular organisation and their expression in vertebrate embryos, with particular emphasis for mammals, are briefly summarized.In the latter part we analysed the expression of four mouse homeobox genes related to twoDrosophila genes expressed in the developing head of the fly: Emx1 and Emx2, related toems, and Otx1 and Otx2, related tootd. 相似文献
56.
Several products of metabolism and aromatic ring cleavage of 3-methoxy and 3,4-dimethoxycinnamic acid from ligninolytic cultures of Lentinus edodes were isolated and identified. 相似文献
57.
Polygalacturonase-inhibiting protein accumulates in Phaseolus vulgaris L. in response to wounding, elicitors and fungal infection 总被引:7,自引:0,他引:7
Carl W. Bergmann Yuki Ito Darrell Singer Peter Albersheim Alan G. Darvill Nicole Benhamou Laurence Nuss Giovanni Salvi Felice Cervone Giulia De Lorenzo 《The Plant journal : for cell and molecular biology》1994,5(5):625-634
Polygalacturonase-inhibiting protein (PGIP) is a cell wall-associated protein that specifically binds to and inhibits the activity of fungal endopolygalacturonases. The Phaseolus vulgaris gene encoding PGIP has been cloned and characterized. Using a fragment of the cloned pgip gene as a probe in Northern blot experiments, it is demonstrated that the pgip mRNA accumulates in suspension-cultured bean cells following addition of elicitor-active oligogalacturonides or fungal glucan to the medium. Rabbit polyclonal antibodies specific for PGIP were generated against a synthetic peptide designed from the N-terminal region of PGIP; the antigenicity of the peptide was enhanced by coupling to KLH. Using the antibodies and the cloned pgip gene fragment as probes in Western and Northern blot experiments, respectively, it is shown that the levels of PGIP and its mRNA are increased in P. vulgaris hypocotyls in response to wounding or treatment with salicylic acid. Using gold-labeled goat-anti-rabbit secondary antibodies in EM studies, it has also been demonstrated that, in bean hypocotyls infected with Colletotrichum lindemuthianum, the level of PGIP preferentially increases in those cells immediately surrounding the infection site. The data support the hypothesis that synthesis of PGIP constitutes an active defense mechanism of plants that is elicited by signal molecules known to induce plant defense genes. 相似文献
58.
Christina Brahe Isabella Velonà Gerrit van der Steege Stefania Zappata Anneke Y. van de Veen Jan Osinga Carli M. J. Tops Riccardo Fodde P. Meera Khan Charles H. C. M. Buys Giovanni Neri 《Human genetics》1994,93(5):494-501
The locus responsible for the childhood-onset proximal spinal muscular atrophies (SMA) has recently been mapped to an area of 2–3 Mb in the region q12–13.3 of chromosome 5. We have used a series of radiation hybrids (RHs) containing distinct parts of the SMA region as defined by reference markers. A cosmid library was constructed from one RH. Thirteen clones were isolated and five of these were mapped within the SMA region. Both RH mapping and fluorescence in situ hybridization analysis showed that two clones map in the region between loci D5S125 and D5S351. One of the cosmids contains expressed sequences. Polymorphic dinucleotide repeats were identified in both clones and used for segregation analysis of key recombinant SMA families. One recombination between the SMA locus and the new marker 9Ic (D5S685) indicates that 9Ic is probably the closest distal marker. The absence of recombination between the SMA locus and marker Fc (D5S684) suggests that Fc is located close to the disease gene. These new loci should refine linkage analysis in SMA family studies and may facilitate the isolation of the disease gene. 相似文献
59.
Giovanni Mita Carmela Gerardi Antonio Miceli Roberto Bollini Pietro De Leo 《Plant cell reports》1994,13(7):406-410
Summary An in vitro culture of Alkanna tinctoria Tausch cells was set up in order to investigate the possibility of producing alkannin, a red naphthoquinone naturally present in the root bark of this plant. Furthermore, an in vitro culture of callusderived roots was established and the production of alkannin evaluated. In the different experimental conditions investigated, differences in the production of alkannin derivatives as well as in the type of pigments produced, were observed. The potential use of this technology is discussed. 相似文献
60.
The microsomal epoxide hydrolase (mEH)-catalyzed hydrolysis of cis-4,4′–dimethylstilbene oxide ( 1a ), cis-4,4′-diethylstilbene oxide ( 1b ), cis-4,4′-diisopropylstilbene oxide ( 1c ), and cis-4,4′-dichlorostilbene oxide ( 1d ) have been investigated using rabbit liver microsomal preparations. The kinetic parameters, Km and Vmax, and the absolute stereochemistry of the reactions have been determined and compared with those of cis-stilbene oxide ( 1e ). All epoxides 1a – d are hydrolyzed by mEH with high product enantioselectivity to give (R,R)-(+)-diols with ee ≥ 90%. The presence of the substituents on the phenyl rings markedly reduces the rates of mEH catalyzed hydrolysis with respect to cis-stilbene oxide, by increasing Km and reducing Vmax in the cases of 1a , 1b , and 1d , or reducing only the Vmax in the case of 1c . The very low Vmax, together with a persistent ability to fit into the mEH active site, make all these epoxides, and particularly 1c , inhibitors of cis-stilbene oxide hydrolysis. The kinetic and stereochemical results are interpreted on the basis of the proposed topology of the mEH active site. © 1994 Wiley-Liss, Inc. 相似文献