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Protoplast

About: Protoplast is a research topic. Over the lifetime, 5474 publications have been published within this topic receiving 122468 citations.


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Journal ArticleDOI
TL;DR: It is concluded that a signal is released by wounding that is rapidly transmitted or transported through the plants to induce a profound change in the leaf cell membranes that renders them fragile during protoplast isolation.
Abstract: Within 4 hr after wounding the lower leaves of young potato and tomato plants, a rapid and remarkable change is induced in the cells of upper undamaged leaves that results in extensive lysis of protoplasts during their isolation. Protoplast yields from unwounded upper leaves, 4 hr after wounding a lower leaf by crushing with a hemostat, decreased 25% below yields from leaves of unwounded plants. From 8 to >20 hr after wounding, protoplast yields were less than half of those from control plants. Multiple woundings decreased yields even further, as did chewing of the lower leaves by tobacco hornworms over a period of several minutes. In addition, within 4 hr of excising young tomato plants at their base with a razor blade, a 90% decrease in leaf protoplast yields was recorded. The major loss of protoplasts induced by wounding was primarily due to an increased cell lysis during protoplast isolation. Cell lysis was apparently due to a weakened cell membrane, because newly recovered protoplasts released from leaves of wounded plants were extremely fragile and exhibited 70% lysis during low speed centrifugation, compared to 20% lysis of protoplasts recovered from control plants. We conclude that a signal is released by wounding that is rapidly transmitted or transported through the plants to induce a profound change in the leaf cell membranes that renders them fragile during protoplast isolation. It is proposed that this signal may play a role in inducing cellular changes in the plant cells as part of their responses to environmental stress such as pest attacks.

45 citations

Journal ArticleDOI
TL;DR: Larvae of Galleria mellonella (Lepidoptera) displayed a strong cellular reaction to the walled-stage hyphal bodies of the entomopathogenic fungus Entomophaga aulicae (Entomophthorales), while no reaction was observed against the wall-less protoplasts.
Abstract: SUMMARY: Larvae of Galleria mellonella (Lepidoptera) displayed a strong cellular reaction to the walled-stage hyphal bodies of the entomopathogenic fungus Entomophaga aulicae (Entomophthorales). In contrast, no reaction was observed against the wall-less protoplasts. This phenomenon was not due to an inhibition of the cellular response by secretion of a toxin by protoplasts. Furthermore, no molecular mimicry was observed between host and protoplast antigens. Host macromolecules which could protect them from being recognized as foreign did not attach to the protoplasts. Ultrastructural and chemical studies of hyphal body and protoplast surfaces of E. aulicae demonstrated the presence of 1,3-β-glucan and chitin on the hyphal wall, whereas these components were absent on the protoplast surface. Since purified 1,3-β-glucan and chitin isolated from E. aulicae and from another entomophthoralean species, Conidiobolus obscurus, induced their haemocytic encapsulation in vitro, it is suggested that these wall components are responsible for the recognition of hyphal body elements, and that their absence accounts for the ability of protoplasts to escape encapsulation.

45 citations

Journal ArticleDOI
01 May 1981-Planta
TL;DR: Tobacco mesophyll protoplasts cultivated in vitro do not synthesize a measurable quantity of chloroplastic ribosomal RNA, but actively synthesize cytoplasmic ribosome RNA, polyadenylated RNA, and proteins, which are related to the ageing phenomenon induced by isolation from the plant and in-vitro culture.
Abstract: Tobacco mesophyll protoplasts cultivated in vitro do not synthesize a measurable quantity of chloroplastic ribosomal RNA, but actively synthesize cytoplasmic ribosomal RNA, polyadenylated RNA, and proteins. These syntheses are essentially independent of the presence of hormones in the culture medium and are thus related to the ageing phenomenon induced by isolation from the plant and in-vitro culture. At all stages of culture and in all culture media, protoplasts incorporate low levels of thymidine into their DNA. However, the incorporation of considerable quantities of thymidine, indicative of the S phase, only takes place after 25–30 h and requires the presence of auxin and cytokinin.

45 citations

Journal ArticleDOI
TL;DR: The degree of genome separation calculated for different cell clones remained constant during in vitro propagation of cells but was significantly lower for subclones derived from colchicine-treated cells, concluding that spatial chromosome arrangement in metaphase is epigenetically controlled.
Abstract: Chromosome spatial arrangements on metaphase plates of intergeneric intertribal cell hybrids of Nicotiana chinensis and Atropa belladonna as well as interspecific somatic hybrid plants of Nicotiana plumbaginifolia and Nicotiana sylvestris were analyzed. In the metaphases of the first divisions of protoplast fusion products, chromosomes of the two parents were spatially separated (segmented metaphase). In long-term cultured somatic hybrids, the topology of genome separation pattern in both callus cells and plants showed changes in form from “segmental” to “radial.” Growing the hybrid cells in the presence of colchicine resulted in random chromosome arrangement both in cells directly exposed to different colchicine concentrations and in colchicine-treated cells grown in colchicine-free media. The degree of genome separation calculated for different cell clones remained constant during in vitro propagation of cells but was significantly lower for subclones derived from colchicine-treated cells. Therefore, it is concluded that spatial chromosome arrangement in metaphase is epigenetically controlled.

45 citations

Journal ArticleDOI
01 Oct 1990-Planta
TL;DR: It is suggested that the PR-IP is a biologically active glycoprotein which induces the release of gametic protoplasts from mt− cells of thisClosterium complex.
Abstract: When mating-type minus (mt−) and plus (mt+) cells of theClosterium peracerosum-strigosum-littorale complex were mixed together in a nitrogen-deficient mating medium, cells of both types released protoplasts, this release being the first step in the process of conjugation. Release of protoplasts by mt− cells also proceeded without pairing in a medium in which mt− and mt+ cells had previously been cultured together. A protein with the ability to induce the release of protoplasts was purified from this medium by sequential column-chromatographic steps, and named PR-IP (protoplast-release-inducing protein). The PR-IP had an apparent molecular mass (Mr) of 95000 on gel filtration and could be separated into several isoforms by anion-exchange chromatography. Each isoform consisted of two glycopolypeptides of Mrs 42000 and 19000, while the deglycosylated polypeptides had Mrs of 34000 and 18000, respectively. From an analysis of dose-response curves, the numbers of PR-IP molecules required for the release of a protoplast by a single cell was calculated as 1.5·109 and the concentration required for 50% of the maximum response (ED50) as 4.1·10−9M. We suggest that the PR-IP is a biologically active glycoprotein which induces the release of gametic protoplasts from mt− cells of thisClosterium complex.

45 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202358
2022153
202160
202060
201978
201855