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61.
Sandra I. Pitta-Alvarez Fabricio Medina-Bolivar María A. Alvarez Agustina A. Scambatto Patricia L. Marconi 《In vitro cellular & developmental biology. Plant》2008,44(6):502-507
Berberis buxifolia Lam., known as “Calafate”, is a plant native to Argentina that exhibits antimicrobial activity. This biological activity
is attributed to the isoquinoline alkaloid berberine. The aim of this research was to test the antimicrobial properties of
different extracts of this species, taking berberine as the reference molecule, and to examine if the expression of bacterial
multidrug resistance (MDR) efflux pumps could be responsible for possible resistance mechanisms. To this end, a wild-type
and a mutant strain of Staphylococcus aureus with a defective MDR efflux pump were used and the minimum inhibitory concentrations of the extracts were determined. The
studies were carried out with infusions of in vivo shoots and “Calafate” commercial tea, as well as with the media derived from shoot cultures incubated with different plant
growth regulators (thidiazuron, picloram, and jasmonic acid). As far as antimicrobial activity is concerned, all the extracts
tested were significantly more effective than berberine standard. “Calafate” commercial tea and shoot tea had inhibitory concentrations
similar to the one observed for ampicillin standard. The media from the shoot cultures, however, were significantly more effective
than all the others, particularly the one derived from jasmonic acid, suggesting the presence of compounds that could be acting
synergistically with berberine. There were no differences in antimicrobial activity against the wild-type and the mutant S. aureus; no definite conclusions could be drawn concerning the relationship between MDR pumps and possible pathogen resistance to
extracts of B. buxifolia. 相似文献
62.
Erika?Mroginski Hebe?Y.?ReyEmail author Ana?M.?Gonzalez Luis?A.?Mroginski 《Journal of Plant Growth Regulation》2004,23(2):129-134
Arachis correntina (Burkart) Krapov. & W.C. Gregory is a herbaceous perennial leguminous plant growing in the Northeast of the Province Corrientes, Argentina. It is important as forage. The development of new A. correntina cultivars with improved traits could be facilitated through the application of biotechnological strategies. The purpose of this study was to investigate the plant regeneration potential of mature leaves of A. correntina in tissue culture. Buds were induced from both petiole and laminae on 0.7% agar-solidified medium containing 3% sucrose, salts and vitamins from Murashige and Skoog (MS) supplemented with 0.5–25 M thidiazuron (TDZ). Shoot induction was achieved by transference of calli with buds to MS supplemented with 5 M TDZ. Fifty-four percent of the regenerated shoot rooted on MS + 5 M naphthaleneacetic acid. Histological studies revealed that shoots regenerated via organogenesis. 相似文献
63.
Syed Bilal Ahmad Andrabi Michiru Tahara Ryuma Matsubara Tomoko Toyama Hiroka Aonuma Hitoshi Sakakibara Makoto Suematsu Kazuyuki Tanabe Tomoyoshi Nozaki Kisaburo Nagamune 《Parasitology international》2018,67(1):47-58
Cytokinins are plant hormones that are involved in regulation of cell proliferation, cell cycle progression, and cell and plastid development. Here, we show that the apicomplexan parasites Toxoplasma gondii and Plasmodium berghei, an opportunistic human pathogen and a rodent malaria agent, respectively, produce cytokinins via a biosynthetic pathway similar to that in plants. Cytokinins regulate the growth and cell cycle progression of T. gondii by mediating expression of the cyclin gene TgCYC4. A natural form of cytokinin, trans-zeatin (t-zeatin), upregulated expression of this cyclin, while a synthetic cytokinin, thidiazuron, downregulated its expression. Immunofluorescence microscopy and quantitative PCR analysis showed that t-zeatin increased the genome-copy number of apicoplast, which are non-photosynthetic plastid, in the parasite, while thidiazuron led to their disappearance. Thidiazuron inhibited growth of T. gondii and Plasmodium falciparum, a human malaria parasite, suggesting that thidiazuron has therapeutic potential as an inhibitor of apicomplexan parasites. 相似文献
64.
Yeh-Jin Ahn Louisa Vang Thomas A. McKeon Grace Q. Chen 《In vitro cellular & developmental biology. Plant》2007,43(1):9-15
An efficient plant regeneration protocol was established for castor (Ricinus communis L.). Hypocotyl tissue from zygotic embryo axis produced adventitious shoots when treated with either thidiazuron (TDZ, 1 μM)
or 6-benzylaminopurine (BA, 20 μM). TDZ resulted in more than a threefold higher rate of shoot induction (a maximum of 24.2
shoots per explant) than BA (6.8 shoots). Our results also showed that the pretreatment of explants in the dark increased
the number of shoots regenerated per explant by 82% and 36% with TDZ and BA, respectively. The elongation of hypocotyl tissue
in the dark appears to be the primary cause of the increase. Comparable rates of rooting were achieved on the media supplemented
with either indole-3-butyric acid (IBA, 84.3%) or 1-naphthaleneacetic acid (NAA, 87.4%) at 5 μM. However, IBA was more efficient
in promoting root and shoot development, resulting in a higher rate of establishment (93.5%) in the soil, compared to the
rate with NAA (39.5%). Histological analysis showed the adventitious induction of the shoot buds originated from the cortex
of the hypocotyl tissue. 相似文献
65.
Amal Aboul Nasr 《Mycorrhiza》1993,2(4):179-182
Seeds of tomato (Lycopersicon lycopersicum var. Peto 86) were planted in soil inoculated with two vesicular-arbuscular mycorrhizal isolates (Glomus intraradices Schenck & Smith). After 7 weeks, plants were transplanted to the field and sprayed twice with cytokinin and thidiazuron, at 50% flowering and 3 weeks later. These treatments significantly increased the percentage of infected roots (30–43%) and chlorophyll content (8–13%). Mycorrhizal plants had less carbohydrates in the roots than in the leaves. Total protein and phenylalanine contents showed pronounced increases, while proline content decreased. Treatment of the mycorrhizal plants with thidiazuron or cytokinin significantly increased plant dry weight (51–54%), and the tomato yield significantly increasecd after inoculation with both isolates (18–35% and 14–32%). 相似文献
66.
Micropropagation of Bambusa edulis through nodal explants of field-grown culms and flowering of regenerated plantlets 总被引:5,自引:0,他引:5
Nodal explants obtained from 10-year-old field-grown culms of Bambusa edulis produced multiple shoots on a Murashige-and-Skoog-based medium supplemented with 0.1 mg/l of thidiazuron (TDZ). Hundreds
of regenerated shoots rooted well on a medium supplemented with 0.01 mg/l TDZ and 0.5 mg/l 2,4-dichlorophenoxyacetic acid
and were successfully transferred to soil for field trials. Albinism occurred at the rate of about 30% among the regenerated
shoots, and isolated albino shoots also proliferated on the medium containing TDZ. Some of the green and albino shoots also
flowered on the medium containing TDZ. A potted plant also flowered and survived after flowering.
Received: 20 August 1997 / Revision received: 12 December 1997 / Accepted: 12 January 1998 相似文献
67.
Murashige and Skoog’s (MS) basal medium with benzylaminopurine (BA), kinetin (KN), zeatin (Z), and thidiazuron (TDZ) were
tested for induction of multiple shoots from mature-tree-derived axillary meristems of Pongamia pinnata. Sprouting of buds was 64% on medium devoid of plant growth regulators (PGR). Incorporation of BA, KN, or Z was ineffective
in enhancing sprouting frequency or induction of multiple shoots. Sprouting was completely suppressed in the presence of TDZ.
Caulogenic buds appeared in nodal meristems of these explants after withdrawal of TDZ. The number of shoot buds was more on
explants precultured in higher concentrations. At higher concentrations of this PGR, a swelling developed at the axil. Multiple
shoot primordia appeared and differentiated from this swelling after culturing these explants on MS medium for six passages
of 2 wk each. Shoots were harvested and cultured on 0.45 μM TDZ for further proliferation. Primary explants after harvesting
of shoots were identified as ‘stump’. Reculturing of stumps on 0.45 μM TDZ produced more shoots. This step was followed for
six cycles to obtain additional shoots in each cycle. Shoots maintained on 0.45 μM TDZ elongated and rooted (70%) on growth
regulator-free medium. Rooted shoots (65%) survived transfer to a sand/soil mixture. This report describes the protocol for
micropropagation of P. pinnata using mature-tree-derived nodal meristems. Recycling of mature stock to produce a stream of useable shoots for subculturing
and eventual stabilization is of great value and can possibly be generalized as an isolation protocol especially for woody
species. Repeated proliferation of caulogenic buds from the same origin may also find application in rescue of endangered
germplasm. 相似文献
68.
Reinerio Benega Garcia Aroldo Cisneros Bert Schneider Noemi Tel-Zur 《Plant cell reports》2009,28(5):719-726
Gynogenesis was investigated on the allotetraploid Selenicereus megalanthus and the diploid Hylocereus polyrhizus and Hylocereus undatus vine cactus species. Unpollinated ovules from developing flower buds containing microspores at middle uninucleate developmental
stage were cultured on MS basal medium containing 2,4-D/TDZ with different sucrose concentrations. Ovule size increased under
dark culture conditions in all the three species and the level of response was species and sucrose concentration dependent.
The best responses were achieved in the two S. megalanthus accessions, E-123 and J-80, at 0.18 and 0.26 M sucrose. Only ovule enlargement was obtained in H. undatus and both ovule enlargement and callus were obtained in H. polyrhizus. Development in both species ceased and embryoids were not formed. Plant regeneration was directly and indirectly obtained
in both S. megalanthus accessions. Ploidy level was determined for a total of 29 S. megalanthus gynogenic plants using flow cytometry: 15 were found to be dihaploid (plants with the gametophytic chromosome number) and
the other 14 were found to have higher ploidy levels. This is the first report of successful gynogenesis in Cactaceae. The
dihaploids of S. megalanthus successfully produced by ovule culture techniques opens new perspectives in vine cacti breeding. 相似文献
69.
Regeneration of Acacia mangium through somatic embryogenesis 总被引:2,自引:0,他引:2
Somatic embryogenesis and whole plant regeneration were achieved in callus cultures derived from immature zygotic embryos
of Acacia mangium. Embryogenic callus was induced on MS medium containing combinations of TDZ (1–2 mg/l), IAA (0.25–2 mg/l) and a mixture of
amino acids. Globular embryos developed on embryogenic callus cultured on the induction medium. Nearly 42% of embryogenic
cultures with globular embryos produced torpedo- and cotyledonary-stage embryos by a two-step maturation phase. The first
stage occurred on 1/2-strength MS basal medium containing 30 g/l sucrose and 5 mg/l GA3 followed by the second stage on 1/2-strength MS basal medium containing 50 g/l sucrose. Of the cotyledonary-stage somatic
embryos, 11% germinated into seedlings that could be successfully transferred to pots. Light- and scanning electron microscopy
showed that the somatic embryos originated from single cells of the embryogenic callus. Further, a single cell layer could
be detected beneath the developing somatic embryos that appeared to be a demarcation layer isolating the somatic proembryonic
structure from the rest of the maternal callus. A suspensor-like structure connected the globular embryos to the demarcation
layer. This is the first successful report of plant regeneration through somatic embryogenesis for this economically important
tropical forest species.
Received: 20 January 2000 / Revision received: 28 September 2000 / Accepted: 29 September 相似文献
70.
The effects of various growth regulators in Bambusa edulis inflorescence proliferation were studied. Cytokinin is essential for inflorescence proliferation. Thidiazuron (TDZ) had been the most efficient cytokinin to induce inflorescence proliferation. The optimal TDZ concentration was 0.01–0.1 mg l–1. Inflorescences did not proliferate in media containing auxin, gibberellic acid (GA3), abscisic acid (ABA), or 1-amino- cyclopropane-1-carboxylic acid (ACC) alone. In TDZ-containing medium, the proliferation ratio decreased when the naphthaleneacetic acid (NAA) concentration higher than 5 mg l–1. 相似文献