988 resultados para Grevillea longevity


Relevância:

80.00% 80.00%

Publicador:

Resumo:

The longevity of Grevillea 'Sylvia' inflorescences can be very short and is influenced by exposure to ethylene. Gibberellic acid has the potential to delay senescence in some cut flowers by acting as an anti-ethylene treatment. Gibberellic acid was therefore applied to Grevillea 'Sylvia' inflorescences in vase solutions to determine its effects on longevity. Treatments with gibberellic acid did not prolong the longevity of inflorescences or influence 1-aminocyclopropane-1-carboxylic acid concentrations. Treatments at high gibberellic acid concentrations enhanced flower abscission and we therefore conclude that vase-applied gibberellic acid treatments are not suitable for extending the longevity of cut Grevillea 'Sylvia' inflorescences.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Exogenous treatments with cytokinins, such as 6-benzylaminopurine (BA), can delay senescence of some plant tissues. Grevillea 'Sylvia' inflorescences have a short vase life. BA supplied in vase solutions at up to 0.1 mM did not delay senescence of G. 'Sylvia' in florescences. However, BA applied by dipping at concentrations up to 10 mM extended their vase life (longevity). Senescence parameters of relative fresh weight, flower abscission, flower opening, flower discolouration and flower wilting were all suppressed by BA dips. Dip treatment with BA (1 mM) was effective on G. 'Sylvia' in florescences at three different maturity stages.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This study aimed to determine the cellular aging of osteophyte-derived mesenchymal cells (oMSCs) in comparison to patient-matched bone marrow stromal cells (bMSCs). Extensive expansion of the cell cultures was performed and early and late passage cells (passages 4 and 9, respectively) were used to study signs of cellular aging, telomere length, telomerase activity, and cell-cycle-related gene expression. Our results showed that cellular aging was more prominent in bMSCs than in oMSCs, and that oMSCs had longer telomere length in late passages compared with bMSCs, although there was no significant difference in telomere lengths in the early passages in either cell type. Telomerase activity was detectable only in early passage oMSCs and not in bMSCs. In osteophyte tissues telomerase-positive cells were found to be located perivascularly and were Stro-1 positive. Fifteen cell-cycle regulator genes were investigated and only three genes (APC, CCND2, and BMP2) were differentially expressed between bMSC and oMSC. Our results indicate that oMSCs retain a level of telomerase activity in vitro, which may account for the relatively greater longevity of these cells, compared with bMSCs, by preventing replicative senescence. J. Cell. Biochem. 108: 839-850, 2009. (c) 2009 Wiley-Liss, Inc.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

If there is one television programming staple for which Australian television drama is known internationally, it is the long-running television soap, with Neighbours (originally produced by Grundy in 1985) lauded as 'the most outstanding example of Australian series export' (Cunningham and Jacka, 1996). Twenty-five years on, this program still airs on domestic and international TV schedules five days a week, despite waning popularity with local Australian audiences. Considering past interest in the success and longevity of this soap, it is apposite to look again at the continuing progress of Neighbours foremost as a global brand. In comparison, Packed to the Rafters is treated here as a contemporary version of familiar Aussie themes related to everyday middle-class suburbia, populated with blue skies and feel-good characters expressing wholesome family values, but with a stylistic innovation defined here as domestic realism. As part of the production ecology of the late 2000s, Packed to the Rafters demonstrates the considerable role for local drama productions as loss leaders and flagship programming for commercial free-to-air networks up against an increasingly difficult domestic market.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This work is part of a series of chemical investigations of the genus Grevillea. Two new arbutin derivatives, seven new bisresorcinols, including a mixture of two isomers, three known flavonol glycosides, and four known resorcinols, including a mixture of two homologous compounds, were isolated from the ethyl acetate extract of the leaves and methanol extract of the stems of Grevillea banksii. The new compounds were identified, on the basis of spectroscopic data, as 6'-O-(3-(2(hydroxymethyl)acryloyloxy)-2-methylpropanoyl)arbutin (1), 6'-O-(2-methylacryloyl)arbutin (2), 5,5'-(4(Z)-dodecen-1,12diyl)bisresorcinol (6), 2'-methyl-5,5'-(4(Z)-tetradecen-1,14-diyl)bisresorcinol (8), 2,2'-di(4-hydroxyprenyl)-5,5'-(6(Z)-tetradecen-1,14-diyl)bisresorcinol (9), 2-(4-acetoxyprenyl)-2'-(4-hydroxyprenyl) 5,5'-(6(Z)-tetradecen-1,14-diyl)bisresorcinol (10), 2-(4-acetoxyprenyl)-2'-(4-hydroxyprenyl)5,5'-(8(Z)-tetradecen-l,14-diyl)bisresorcinol (11), 5,5'-(10(Z)-tetradecen-1-on-diyl)bisresorcinol (12) and 5,5'-(4(Z)-tetradecen-1-on-diyl)bisresorcinol (13).

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Seven new and three known bisresorcinols, grevirobstol A(=5,5'-((6Z,9Z)-hexadeca-6,9-diene-1,16-diyl)bisresorcinol; 8), 5,5'-[(8Z)-hexadec-8-ene-1,16-diyl]bisresorcinol (9), and 2-methyl-5,5'-[8Z)-hexadec-8-ene-1,16-diyl] bisresorcinol (10) were isolated from the stems of Grevillea glauca. The new compounds were identified on the basis of spectroscopic data as (Z)-6,7-didehydroglaucone A (1), glaucones A and B (2 and 3, resp.), 2-(3-hydroxyisopentyl)bisnorstriatol (4), 2-(3-methylbut-2-en-1-yl)bisnorstriatol (5), 2'-methylgrebustol A (6), and glaucane (7).

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Bats account for one-fifth of mammalian species, are the only mammals with powered flight, and are among the few animals that echolocate. The insect-eating Brandt’s bat (Myotis brandtii) is the longest-lived bat species known to date (lifespan exceeds 40 years) and, at 4–8 g adult body weight, is the most extreme mammal with regard to disparity between body mass and longevity. Here we report sequencing and analysis of the Brandt’s bat genome and transcriptome, which suggest adaptations consistent with echolocation and hibernation, as well as altered metabolism, reproduction and visual function. Unique sequence changes in growth hormone and insulin-like growth factor 1 receptors are also observed. The data suggest that an altered growth hormone/insulin-like growth factor 1 axis, which may be common to other long-lived bat species, together with adaptations such as hibernation and low reproductive rate, contribute to the exceptional lifespan of the Brandt’s bat.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Eleven new bisresorcinols including four mixtures each of two isomers and one resorcinol/phloroglucinol derivative, together with five known resorcinols have been isolated from the ethyl acetate extract of sterns of Grevillea whiteana. The new Compounds were identified as 4-(3-hydroxy-3-methylbutyl)grebustol-B (10a), 4'-(3-hydroxy-3-methylbutyl)grebustol-B (10b), 4-(4-hydroxy-3-methylbutyl)grebustol-B (2a) and 4'-(4-hydroxy-3-methylbutyl) rebustol-B (2b), 2,2-dimethyldihydropyrano grebustol-B (11a) and iso-2,2-dimethyldihydropyranogrebustol-B (11b), 2,2-dimethyl-3 xi-hydroxydihydropyranogrebustol-B (7a) and iso-2,2-dimethyl-3 xi-hydroxydihydropyranogrebustol-B (7b), 15-(2-(4-hydroxy-3-methylbutyl)-resorcinol-5-yl)-1-(phloroglucinolyl )-9(Z)pentadecen-one (whiteanone) (4), 5,5'-(hexadecan-diyl)bisresorcinol (12) and 2-methyl-5,5'-(8(Z)hexadecen-1,16-diyl)bisresorcinol (9). This is the first record of pyranobisresorcinols in the genus and the first report of a phloroglucinol terminal Phenolic unit in any Grevillea species.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Seven new bisresorcinol derivatives, together with four known resorcinols. have been isolated from the ethyl acetate extract of the sterns of Grevillea floribunda. Five of the new compounds (floribol A-E) were characterized as bisnorstriatol derivatives Substituted at C-2 of both resorcinol units with variously modified prenyl (3-methylbut-2-enyl) units. The remaining two new compounds are similarly Substituted derivatived of grebustol-B. (c) 2008 Phytochemical Society of Europe Published by Elsevier B.V. All rights reserved.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Subterranean mammals spend their lives in dark, unventilated environments that are rich in carbon dioxide and ammonia and low in oxygen. Many of these animals are also long-lived and exhibit reduced aging-associated diseases, such as neurodegenerative disorders and cancer. We sequenced the genome of the Damaraland mole rat (DMR, Fukomys damarensis) and improved the genome assembly of the naked mole rat (NMR, Heterocephalus glaber). Comparative genome analyses, along with the transcriptomes of related subterranean rodents, revealed candidate molecular adaptations for subterranean life and longevity, including a divergent insulin peptide, expression of oxygen-carrying globins in the brain, prevention of high CO2-induced pain perception, and enhanced ammonia detoxification. Juxtaposition of the genomes of DMR and other more conventional animals with the genome of NMR revealed several truly exceptional NMR features: unusual thermogenesis, an aberrant melatonin system, pain insensitivity, and unique processing of 28S rRNA. Together, these genomes and transcriptomes extend our understanding of subterranean adaptations, stress resistance, and longevity.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The 12.7-10.5 Ma Cougar Point Tuff in southern Idaho, USA, consists of 10 large-volume (>10²-10³ km³ each), high-temperature (800-1000 °C), rhyolitic ash-flow tuffs erupted from the Bruneau-Jarbidge volcanic center of the Yellowstone hotspot. These tuffs provide evidence for compositional and thermal zonation in pre-eruptive rhyolite magma, and suggest the presence of a long-lived reservoir that was tapped by numerous large explosive eruptions. Pyroxene compositions exhibit discrete compositional modes with respect to Fe and Mg that define a linear spectrum punctuated by conspicuous gaps. Airfall glass compositions also cluster into modes, and the presence of multiple modes indicates tapping of different magma volumes during early phases of eruption. Equilibrium assemblages of pigeonite and augite are used to reconstruct compositional and thermal gradients in the pre-eruptive reservoir. The recurrence of identical compositional modes and of mineral pairs equilibrated at high temperatures in successive eruptive units is consistent with the persistence of their respective liquids in the magma reservoir. Recurrence intervals of identical modes range from 0.3 to 0.9 Myr and suggest possible magma residence times of similar duration. Eruption ages, magma temperatures, Nd isotopes, and pyroxene and glass compositions are consistent with a long-lived, dynamically evolving magma reservoir that was chemically and thermally zoned and composed of multiple discrete magma volumes.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The longevity of seed in the soil is a key determinant of the cost and length of weed eradication programs. Soil seed bank information and ongoing research have input into the planning and reporting of two nationally cost shared weed eradication programs based in tropical north Queensland. These eradication programs are targeting serious weeds such as Chromoleana odorata, Mikania micrantha, Miconia calvescens, Clidemia hirta and Limnocharis flava. Various methods are available for estimating soil seed persistence. Field methods to estimate the total and germinable soil seed densities include seed packet burial trials, extracting seed from field soil samples, germinating seed in field soil samples and observations from native range seed bank studies. Interrogating field control records can also indicate the length of the control and monitoring periods needed to exhaust the seed bank. Recently, laboratory tests which rapidly age seed have provided an additional indicator of relative seed persistence. Each method has its advantages, drawbacks and logistical constraints.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Understanding the reproductive biology of Calotropis procera (Aiton) W.T. Aiton, an invasive weed of northern Australia, is critical for development of effective management strategies. Two experiments are reported on. In Experiment 1 seed longevity of C. procera seeds, exposed to different soil type (clay and river loam), pasture cover (present and absent) and burial depth (0, 2.5, 10 and 20 cm) treatments were examined. In Experiment 2 time to reach reproductive maturity was studied. The latter experiment included its sister species, C. gigantea (L.) W.T. Aiton, for comparison and two separate seed lots were tested in 2009 and 2012 to determine if exposure to different environmental conditions would influence persistence. Both seed lots demonstrated a rapid decline in viability over the first 3 months and declined to zero between 15 and 24 months after burial. In Experiment 1, longevity appeared to be most influenced by rainfall patterns and associated soil moisture, burial depth and soil type, but not the level of pasture cover. Experiment 2 showed that both C. procera and C. gigantea plants could flower once they had reached an average height of 85 cm. However, they differed significantly in terms of basal diameter at first flowering with C. gigantea significantly smaller (31 mm) than C. procera (45 mm). On average, C. gigantea flowered earlier (125 days vs 190 days) and set seed earlier (359 days vs 412 days) than C. procera. These results suggest that, under similar conditions to those that prevailed in the present studies, land managers could potentially achieve effective control of patches of C. procera in 2 years if they are able to kill all original plants and treat seedling regrowth frequently enough to prevent it reaching reproductive maturity. This suggested control strategy is based on the proviso that replenishment of the seed bank is not occurring from external sources (e.g. wind and water dispersal).

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Transgenic engineering of plants is important in both basic and applied research. However, the expression of a transgene can dwindle over time as the plant's small (s)RNA-guided silencing pathways shut it down. The silencing pathways have evolved as antiviral defence mechanisms, and viruses have co-evolved viral silencing-suppressor proteins (VSPs) to block them. Therefore, VSPs have been routinely used alongside desired transgene constructs to enhance their expression in transient assays. However, constitutive, stable expression of a VSP in a plant usually causes pronounced developmental abnormalities, as their actions interfere with endogenous microRNA-regulated processes, and has largely precluded the use of VSPs as an aid to stable transgene expression. In an attempt to avoid the deleterious effects but obtain the enhancing effect, a number of different VSPs were expressed exclusively in the seeds of Arabidopsis thaliana alongside a three-step transgenic pathway for the synthesis of arachidonic acid (AA), an ω-6 long chain polyunsaturated fatty acid. Results from independent transgenic events, maintained for four generations, showed that the VSP-AA-transformed plants were developmentally normal, apart from minor phenotypes at the cotyledon stage, and could produce 40% more AA than plants transformed with the AA transgene cassette alone. Intriguingly, a geminivirus VSP, V2, was constitutively expressed without causing developmental defects, as it acts on the siRNA amplification step that is not part of the miRNA pathway, and gave strong transgene enhancement. These results demonstrate that VSP expression can be used to protect and enhance stable transgene performance and has significant biotechnological application.