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11.
Honma M Namikawa K Mansur K Iwata T Mori N Iizuka H Kiyama H 《Journal of neurochemistry》2002,82(4):961-975
Axotomy-induced neuronal death occurs in neonatal motoneurons, but not in adult rat. Here we demonstrated that during the course of postnatal development, nerve injury induced down-regulation of the glial cell line-derived neurotrophic factor (GDNF) receptor GFRalpha1 in axotomized hypoglossal motoneurons of rat are gradually converted to the adult up-regulation pattern of response. The compensatory expression of GFRalpha1 specifically in the injured motoneurons of neonates by adenovirus succeeded in rescuing the injured neurons without an application of growth factors. To the contrary, the nuclear antisense RNA for GFRalpha1 expression accelerates the axotomy-induced neuronal death in pups. These findings suggest that the receptor expression response after nerve injury is critical for the determination of injured motoneuron fate. 相似文献
12.
Reactive oxygen-induced carcinogenesis causes hypermethylation of p16(Ink4a) and activation of MAP kinase 总被引:5,自引:0,他引:5
Govindarajan B Klafter R Miller MS Mansur C Mizesko M Bai X LaMontagne K Arbiser JL 《Molecular medicine (Cambridge, Mass.)》2002,8(1):1-8
BACKGROUND: Implantation of foreign materials into mice and humans has been noted to result in the appearance of soft tissue sarcomas at the site of implantation. These materials include metal replacement joints and Dacron vascular grafts. In addition, occupational exposure to nickel has been shown to result in an increased risk of carcinogenesis. The molecular mechanisms of foreign body-induced carcinogenesis are not fully understood. MATERIALS AND METHODS: In order to gain insight into these mechanisms, we implanted nickel sulfide into wild type C57BL/6 mice as well as a mouse heterozygous for the tumor suppressor gene, p53. Malignant fibrous histiocytomas arose in all mice, and we have characterized the profile of tumor suppressor genes and signal transduction pathways altered in these cells. RESULTS: All tumors demonstrated hypermethylation of the tumor suppressor gene p16, as well as activation of the mitogen activated protein kinase (MAP kinase) signaling pathway. This knowledge may be beneficial in the prevention and treatment of tumors caused by foreign body implantation. CONCLUSIONS: Oxidative stress induced by nickel sulfide appears to cause loss of p16 and activation of MAP kinase signaling. These findings support the hypothesis of synergistic interactions between MAP kinase activation and p16 loss in carcinogenesis. 相似文献
13.
Selective inhibition of selenocysteine tRNA maturation and selenoprotein synthesis in transgenic mice expressing isopentenyladenosine-deficient selenocysteine tRNA 下载免费PDF全文
Moustafa ME Carlson BA El-Saadani MA Kryukov GV Sun QA Harney JW Hill KE Combs GF Feigenbaum L Mansur DB Burk RF Berry MJ Diamond AM Lee BJ Gladyshev VN Hatfield DL 《Molecular and cellular biology》2001,21(11):3840-3852
Selenocysteine (Sec) tRNA (tRNA([Ser]Sec)) serves as both the site of Sec biosynthesis and the adapter molecule for donation of this amino acid to protein. The consequences on selenoprotein biosynthesis of overexpressing either the wild type or a mutant tRNA([Ser]Sec) lacking the modified base, isopentenyladenosine, in its anticodon loop were examined by introducing multiple copies of the corresponding tRNA([Ser]Sec) genes into the mouse genome. Overexpression of wild-type tRNA([Ser]Sec) did not affect selenoprotein synthesis. In contrast, the levels of numerous selenoproteins decreased in mice expressing isopentenyladenosine-deficient (i(6)A(-)) tRNA([Ser]Sec) in a protein- and tissue-specific manner. Cytosolic glutathione peroxidase and mitochondrial thioredoxin reductase 3 were the most and least affected selenoproteins, while selenoprotein expression was most and least affected in the liver and testes, respectively. The defect in selenoprotein expression occurred at translation, since selenoprotein mRNA levels were largely unaffected. Analysis of the tRNA([Ser]Sec) population showed that expression of i(6)A(-) tRNA([Ser]Sec) altered the distribution of the two major isoforms, whereby the maturation of tRNA([Ser]Sec) by methylation of the nucleoside in the wobble position was repressed. The data suggest that the levels of i(6)A(-) tRNA([Ser]Sec) and wild-type tRNA([Ser]Sec) are regulated independently and that the amount of wild-type tRNA([Ser]Sec) is determined, at least in part, by a feedback mechanism governed by the level of the tRNA([Ser]Sec) population. This study marks the first example of transgenic mice engineered to contain functional tRNA transgenes and suggests that i(6)A(-) tRNA([Ser]Sec) transgenic mice will be useful in assessing the biological roles of selenoproteins. 相似文献
14.
R.F. Gagliardi G.P. Pacheco S.P. Coculilo J.F.M. Valls E. Mansur 《Biodiversity and Conservation》2000,9(7):943-951
In vitro regeneration of wild groundnut species from Section Extranervosae (Arachis villosulicarpa, A. macedoi, A. retusa, A. burchellii, A. pietrarellii, A. prostrata, A. aff. prostrata and a new species) was examined for the purpose of germplasm renewal and conservation. Seeds of different ages, stored at the seed bank of CENARGEN/EMBRAPA were either inoculated on culture medium or used as a source of embryo axis and cotyledon explants. Whole seeds failed to germinate on MS either without growth regulators (MS0) or supplemented with 10 M TDZ. Embryo axes cultured on MS0 produced only single plants. In the presence of 8.8 M BAP these explants showed multi-shoot formation. Cotyledons cultured on MS supplemented with 110 M BAP developed adventitious shoots through direct organogenesis. Plant regeneration was obtained from A. villosulicarpa, A. macedoi, A. retusa, A. burchellii and A. pietrarellii both from embryo axes and cotyledons. Explants from A. prostrata and A. aff. prostrata did not produce regenerants. Rooting of shoots was induced in the presence of 5.4 M NAA. Primary plants derived from these explants were further multiplied by culturing nodal segments on MS medium plus 2.7 M NAA. 相似文献
15.
Morphogenesis from several explant types excised from in-vitro-grown plantlets of a Brazilian eggplant (Solanum melongena L.) variety (F-100) was evaluated in response to thidiazuron (TDZ). Leaves and cotyledons were found to be the most responsive
explants. Optimal shoot bud induction rates (75–100 buds/explant) were achieved in the presence of 0.2 μm TDZ. Organogenic calli were transferred to growth regulator free MS medium before shoot excision. Rooting was induced on
half-strength MS medium supplemented with 0.6 μm IAA.
Received: 1 March 1997 / Revision received: 29 October 1997 / Accepted: 15 November 1997 相似文献
16.
V. L. M. Pádua L. D. Fernandes D. E. de Oliveira E. Mansur 《In vitro cellular & developmental biology. Plant》1998,34(4):285-288
An efficient clonal propagation procedure for a Brazilianindica rice subspecies was developed with shoot apex explants. Shoot apices were excised from 4-d-old seedlings and cultured on
MS medium supplemented with 8.9 μM 6-benzyladenine. The efficiency of shoot production was influenced by growth regulators and light treatments to the donor
plant. Explants derived from seedlings growth in the presence of 10.7 μM naphthaleneacetic acid and in the absence of light showed significantly increased regeneration capacity as compared to control
explants. Anatomical analysis of the new shoot meristems revealed that they originated from preexisting apical and axillary
meristem as well as from the mesocotyl parenchyma. 相似文献
17.
In vitro regeneration from leaf explants of Neoregelia cruenta (R. Graham) L.B. Smith,an endemic bromeliad from Eastern Brazil 总被引:1,自引:0,他引:1
Carneiro L.A. Araújo R.F.G. Brito G.J.M. Fonseca M.H.P.B. Costa A. Crocomo O.J. Mansur E. 《Plant Cell, Tissue and Organ Culture》1998,55(2):79-83
An efficient plant regeneration system was developed for the induction of direct shoot formation from leaves derived from
seedlings of Neoregelia cruenta, an endemic Bromeliaceae of Eastern Brazil. Shoot differentiation occurred directly from the
leaf bases. In vitro responses were influenced by seedling age and growth regulator combinations. Highest regeneration rates
were obtained from explants excised from 7-week-old seedlings cultured in the presence of 22 μM BA and 2.5 μM NAA. Shoot conversion
to whole plants was most effective in shoots formed in response to 4.4 or 8.8 μM BA combined with 2.5 μM NAA.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
18.
Daniel Pereira Maria Cristina Dreher Mansur Leandro D. S. Duarte Arthur Schramm de Oliveira Daniel Mansur Pimpão Cláudia Tasso Callil Cristián Ituarte Esperanza Parada Santiago Peredo Gustavo Darrigran Fabrizio Scarabino Cristhian Clavijo Gladys Lara Igor Christo Miyahira Maria Teresa Raya Rodriguez Carlos Lasso 《Hydrobiologia》2014,735(1):15-44
Based on literature review and malacological collections, 168 native freshwater bivalve and five invasive species have been recorded for 52 hydrographic regions in South America. The higher species richness has been detected in the South Atlantic, Uruguay, Paraguay, and Amazon Brazilian hydrographic regions. Presence or absence data were analysed by Principal Coordinate for Phylogeny-Weighted. The lineage Veneroida was more representative in hydrographic regions that are poorer in species and located West of South America. The Mycetopodidae and Hyriidae lineages were predominant in regions that are richest in species toward the East of the continent. The distribution of invasive species Limnoperna fortunei is not related to species richness in different hydrographic regions there. The species richness and its distribution patterns are closely associated with the geological history of the continent. The hydrographic regions present distinct phylogenetic and species composition regardless of the level of richness. Therefore, not only should the richness be considered to be a criterion for prioritizing areas for conservation, but also the phylogenetic diversity of communities engaged in services and functional aspects relevant to ecosystem maintenance. A plan to the management of this fauna according to particular ecological characteristics and human uses of hydrographic regions is needed. 相似文献
19.
Moreira MF Dos Santos AS Marotta HR Mansur JF Ramos IB Machado EA Souza GH Eberlin MN Kaiser CR Kramer KJ Muthukrishnan S Vasconcellos AM 《Insect biochemistry and molecular biology》2007,37(12):1249-1261
An insoluble white substance was prepared from extracts of eggshells of Aedes aegypti, the yellow fever mosquito and dengue vector. Its infrared and proton NMR spectra were similar to that of standard commercial chitin. This putative chitin-like material, also obtained from ovaries, newly laid and dark eggs, was hydrolyzed in acid and a major product was identified by HPLC to be glucosamine. The eggshell acid hydrolysate was also analyzed by ESI-MS and an ion identical to a glucosamine monoprotonated species was detected. The presence of chitin was also analyzed during different developmental stages of the ovary using a fluorescent microscopy technique and probes specific for chitin. The results showed that a chitin-like material accumulates in oocytes during oogenesis. Streptomyces griseus chitinase pre-treatment of oocytes greatly reduced the chitin-derived fluorescence. Chitinase activity was detected in newborn larvae and eggs prior to hatching. Feeding experiments indicated that the chitin synthesis inhibitor lufenuron inhibited chitin synthesis, either when mosquitoes were allowed to feed directly on lufenuron-treated chickens or when an artificial feeding system was used. Lufenuron inhibited egg hatch, larval development and reduced mosquito viability. These data demonstrate for the first time that (1) a chitin-like material is present in A. aegypti eggs, ovaries and eggshells; (2) a chitin synthesis inhibitor can be used to inhibit mosquito oogenesis; and (3) chitin synthesis inhibitors have potential for controlling mosquito populations. 相似文献
20.
Jorge Mansur Medina Juliany Cola Fernandes Rodrigues Otacilio C Moreira Geórgia Atella Wanderley de Souza Hector Barrabin 《Memórias do Instituto Oswaldo Cruz》2015,110(1):48-55
Phytomonas serpens are flagellates in the family Trypanosomatidae that parasitise the
tomato plant (Solanum lycopersicum L.), which results in fruits with low commercial
value. The tomato glycoalkaloid tomatine and its aglycone tomatidine inhibit the
growth of P. serpens in axenic cultures. Tomatine, like many other saponins, induces
permeabilisation of the cell membrane and a loss of cell content, including the
cytosolic enzyme pyruvate kinase. In contrast, tomatidine does not cause
permeabilisation of membranes, but instead provokes morphological changes, including
vacuolisation. Phytomonas treated with tomatidine show an increased accumulation of
labelled neutral lipids (BODYPY-palmitic), a notable decrease in the amount of
C24-alkylated sterols and an increase in zymosterol content. These
results are consistent with the inhibition of 24-sterol methyltransferase (SMT),
which is an important enzyme that is responsible for the methylation of sterols at
the 24 position. We propose that the main target of tomatidine is the sterols
biosynthetic pathway, specifically, inhibition of the 24-SMT. Altogether, the results
obtained in the present paper suggest a more general effect of alkaloids in
trypanosomatids, which opens potential therapeutic possibilities for the treatment of
the diseases caused by these pathogens. 相似文献