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1.
Plant somatic cells have the capability to switch their cell fates from differentiated to undifferentiated status under proper
culture conditions, which is designated as totipotency. As a result, plant cells can easily regenerate new tissues or organs
from a wide variety of explants. However, the mechanism by which plant cells have such remarkable regeneration ability is
still largely unknown. In this study, we used a set of meristem-specific marker genes to analyze the patterns of stem cell
differentiation in the processes of somatic embryogenesis as well as shoot or root organogenesis in vitro. Our studies furnish preliminary and important information on the patterns of the de novo stem cell differentiation during various types of in vitro organogenesis. 相似文献
2.
3.
Haploid plants were regenerated in vitro from unpollinated ovules of niger (Guizotia abyssinica (L. f.) (Cass.) on Murashige and Skoog nutrient medium (MS) supplemented with 10 μM naphthaleneacetic acid or 10 μM NAA +
1.5 μM kinetin and 30 g/l sucrose. Gamborg (B5) medium was the best for plant regeneration (in comparison with MS, Nitsch
and Nitsch (NN), and Chu (N6) media) from cultured ovules, and 6.66 and 7.33 ovules of JNC-6 and Ootacamund cultivars were
involved in direct plant regeneration on this medium. Matured ovules (ovules collected one day before anthesis or on the day
of anthesis) only responded to cultural regimes and involved in direct plantlet development. Cytological preparation of root
tips and chloroplast counts in the guard cells of leaf stomata of regenerated plants confirmed their haploid nature.
This text was submitted by the authors in English. 相似文献
4.
Larvae and nymphs of the tick Ixodes ricinus L. display similar reactions to analogs of the insect juvenile hormones (methoprene and pyriproxyfen), which induce at both stages juvenalization of the Haller's sense organ regenerates. Similar effects were also described for retinoic acid. Unlike juvenoids, retinoic acid can affect not only regeneration, but also normal development of the Haller's organ and cause changes corresponding to so-called regenerative induction. Amputation of the leg and treatment with retinoic acid do not affect the duration of larval or nymphal development, while juvenoids somewhat accelerate their development. 相似文献
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6.
Jameel M. Al-Khayri 《In vitro cellular & developmental biology. Plant》2001,37(4):453-456
Summary This study was conducted to examine the effect of biotin and thiamine concentrations on callus growth and somatic embryogenesis
of date palm (Phoenix dactylifera L.). Embryogenic callus derived from offshoot tip explants was cultured on hormone-free MS medium containing biotin at 0,
0.1, 1, or 2 mg l−1 combined with thiamine at 0.1, 0.5, 2, or 5 mg l−1. Embryogenic callus weight, number of resultant embryos, and embryo length were significantly influenced by thiamine and
biotin concentration. The optimum callus growth treatment consisted of 0.5 mg l−1 thiamine and 2 mg l−1 biotin. This treatment also gave the highest number of embryos. Embryo elongation was greatest at 0.5 or 2 mg l−1 thiamine combined with 1 mg l−1 biotin. Embryos from all treatments germinated and regenerants exhibited normal growth in soil. This study provides an insight
into the importance of optimizing various culture medium components to overcome in vitro recalcitrace of date palm. 相似文献
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8.
During range of motion (max-ROM) tests performed on an isokinetic dynamometer, the mechanical delay between the button press (by the participant to signal their max-ROM) and the stopping of joint rotation resulting from system inertia induces errors in both max-ROM and maximum passive joint moment. The present study aimed to quantify these errors by comparing data when max-ROM was obtained from the joint position data, as usual (max-ROMPOS), to data where max-ROM was defined as the first point of dynamometer arm deceleration (max-ROMACC). Fifteen participants performed isokinetic ankle joint max-ROM tests at 5, 30 and 60° s−1. Max-ROM, peak passive joint moment, end-range musculo-articular (MAC) stiffness and area under the joint moment-position curve were calculated. Greater max-ROM was observed in max-ROMPOS than max-ROMACC (P < 0.01) at 5 (0.2 ± 0.15%), 30 (1.8 ± 1.0%) and 60° s−1 (5.9 ± 2.3%), with the greatest error at the fastest velocity. Peak passive moment was greater and end-range MAC stiffness lower in max-ROMPOS than in max-ROMACC only at 60° s−1 (P < 0.01), whilst greater elastic energy storage was found at all velocities. Max-ROM and peak passive moment are affected by the delay between button press and eventual stopping of joint rotation in an angular velocity-dependent manner. This affects other variables calculated from the data. When high data accuracy is required, especially at fast joint rotation velocities (≥30° s−1), max-ROM (and associated measures calculated from joint moment data) should be taken at the point of first change in acceleration rather than at the dynamometer’s ultimate joint position. 相似文献
9.
Mamta Singhvi Dipti Joshi Shalaka Gaikaiwari Digambar V. Gokhale 《Indian journal of microbiology》2010,50(1):97-100
Method for production and regeneration of Lactobacillus delbrueckii protoplasts are described. The protoplasts were obtained by treatment with a mixture of lysozyme and mutanolysin in protoplast
buffer at pH 6.5 with different osmotic stabilizers. The protoplasts were regenerated on deMan, Rogosa and Sharpe (MRS) with
various osmotic stabilizers. Maximum protoplast formation was obtained in protoplast buffer with sucrose as an osmotic stabilizer
using a combination of lysozyme (1 mg/ml) and mutanolysin (10 μg/ml). Maximum protoplast regeneration was obtained on MRS
medium with sucrose (0.5 M) as an osmotic stabilizer. The regeneration medium was also applicable to other species of lactobacilli
as well. This is, to our knowledge, the first report on protoplast formation and efficient regeneration in case of L. delbrueckii. 相似文献
10.
Johnathan L Meaders Erica F Geers Belen Fernandez‐Garcia Marvin E Tanenbaum 《The EMBO journal》2012,31(21):4179-4190
The microtubule motor protein kinesin‐5 (Eg5) provides an outward force on centrosomes, which drives bipolar spindle assembly. Acute inhibition of Eg5 blocks centrosome separation and causes mitotic arrest in human cells, making Eg5 an attractive target for anti‐cancer therapy. Using in vitro directed evolution, we show that human cells treated with Eg5 inhibitors can rapidly acquire the ability to divide in the complete absence of Eg5 activity. We have used these Eg5‐independent cells to study alternative mechanisms of centrosome separation. We uncovered a pathway involving nuclear envelope (NE)‐associated dynein that drives centrosome separation in prophase. This NE‐dynein pathway is essential for bipolar spindle assembly in the absence of Eg5, but also functions in the presence of full Eg5 activity, where it pulls individual centrosomes along the NE and acts in concert with Eg5‐dependent outward pushing forces to coordinate prophase centrosome separation. Together, these results reveal how the forces are produced to drive prophase centrosome separation and identify a novel mechanism of resistance to kinesin‐5 inhibitors. 相似文献