Protoplasma最新文献

Cryopreservation is a reliable technique for the long-term storage and preservation of embryogenic cells, maintaining their viability without loss of their embryogenic capacity. However, the large-scale conservation of grapevine embryogenic lines in cryobanks remains limited. A significant challenge is understanding somatic cell rejuvenation. Here, we investigate the encapsulation/dehydration and encapsulation/vitrification for cryopreserving embryogenic material. Cell rejuvenation and enhanced embryogenic competence were observed after cryopreservation, as evidenced through structural cellular changes observed by histology and electron scanning microscopy. Results showed that cryopreserved samples of 110-Richter, Riesling, and Tempranillo using encapsulation/dehydration had better survival rates, averaging 81%, 62%, and 48%, respectively, while encapsulation/vitrification yielded lower survival rates, averaging 58%, 42%, and 32%, respectively. Cryopreservation also improved post-thaw recovery and regeneration efficiency assessed through regrowth of proembryogenic masses and somatic embryo conversion reaching 54-72% against 11-17% in control samples. Cryopreservation triggered changes in gene expression patterns and exhibited considerable increase at genotype-specific basis of 1.5- to 4.5-fold in SERK1, BBM, and WOX associated to embryogenic competence as well as in ChitIV and LEA involved in stress response. Membrane stability index, hydrogen peroxide, and proline contents were used as indicators of oxidative stress uncovering a key role of an osmotic trans-priming effect leading to cryotolerance. Our finding highlighted that cryopreservation enhances embryogenic capacity in senescent callus and probably acts as a screening process allowing safe maintenance of proembryogenic cells and promoting their recovery. This study provides a high throughput innovation to set up cryolines for cell rejuvenation of grapevine and other important plant species.

One of the first cellular locations of the calreticulin (CRT) chaperone in eukaryotic cells, apart from its obvious localization in the endoplasmic reticulum (ER), was the cell nucleus (Opas et al. 1991). The presence of CRT has been detected inside the nucleus and in the nuclear envelope of animal and plant cells, and a putative nuclear localization signal (NLS) in the CRT amino acid sequence has been mapped in several animal and plant species. Over the last 30 years, other localization sites of this protein outside the ER and cell nucleus have also been discovered, suggesting that CRT is a multifunctional Ca²⁺-binding protein widely found in various cell types. In our previous studies focusing on plant developmental biology, we have demonstrated the presence of CRT inside and outside the ER in highly specialized plant cells, as well as the possibility of CRT localization in the cell nucleus. In this paper, we present a detailed analysis of immunocytochemical localization of CRT inside nuclei of the pistil transmission tract somatic cells before and after pollination. We show a similar pattern of the nuclear CRT localization in relation to exchangeable Ca²⁺ for two selected species of angiosperms, dicotyledonous Petunia and monocot Haemanthus, that differ in anatomical structure of the pistil and discuss the potential role of CRT in the cell nucleus.

Monoclonal antibodies (mAbs) have become indispensable tools in various fields, from research to therapeutics, diagnostics, and industries. However, their production, primarily in mammalian cell culture systems, is cost-intensive and resource-demanding. Microalgae, diverse photosynthetic microorganisms, are gaining attention as a favorable option for manufacturing mAbs and various other recombinant proteins. This review explores the potential of microalgae as a robust expression system for biomanufacturing high-value proteins. It also highlights the diversity of microalgae species suitable for recombinant protein. Nuclear and chloroplast genomes of some microalgae have been engineered to express mAbs and other valuable proteins. Codon optimization, vector construction, and other genetic engineering techniques have significantly improved recombinant protein expression in microalgae. These accomplishments demonstrate the potential of microalgae for biopharmaceutical manufacturing. Microalgal biotechnology holds promise for revolutionizing the production of mAbs and other therapeutic proteins, offering a sustainable and cost-effective solution to address critical healthcare needs.

Cell suspension culture has the potential to be a valuable source for the bioactive compound productions. In this study, an optimized procedure was established for callus and cell suspension culture of Physalis alkekengi for the first time, and the impact of static magnetic field (SMF, 6 mT) was studied on the high-value metabolic compounds through investigation of signaling molecules and gene expressions at the late log-to-stationary phase. Results showed that the growth regulators of 6-benzyl amino purine (BAP, 1.5 mg^-1 L) and 1-naphthaleneacetic acid (NAA, 0.4 mg^-1 L) induced the highest fresh weight, callus rate, callus index, and total withanolides. Cell suspension culture was established in the liquid MS medium supplied with BAP (1.5 mg^-1 L) and NAA (0.1 mg^-1 L). SMF application decreased slightly the cell growth and viability and enhanced the number of round-shaped cells. The hydrogen peroxide (H₂O₂) and nitric oxide (NO) levels increased at an all-time series after SMF exposure, and their maximum contents were observed after 12 h. A significant alteration of malondialdehyde content was also identified after 12 h of SMF exposure. The expression of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR), 1-deoxyD-xylulose 5-phosphate synthase (DXS), squalene synthase (SQS), sterol Δ7-reductase (DWF5), and C-7,8 sterol isomerase (HYD1) genes was upregulated significantly after 24 and 48 h. An increase in the total withanolides was related to more activity of HMGR and DXS enzymes in SMF-exposed cells and the maximum physalin A (12.8 mg g^-1 DW) and physalin B (1.92 mg g^-1 DW) obtained after 24 h compared to controls. Findings suggest that SMF can play a supportive factor in inducing steroidal compounds in P. alkekengi through modulating H₂O₂ and NO levels and the related-gene expressions.

Autophagy regulates the formation of primary cilia, which in turn affects autophagy. The relationship between autophagy and cilia is known to be bidirectional although the specific mechanisms involved have yet to be elucidated. In this study, we found for the first time that ATG8 protein localizes in the basal body of the dorsal kineties and the base of the ventral cirri in Euplotes amieti. ATG8 protein maintains the structural integrity of cilia and plays a role in the construction of the cortical ciliature and microtubule cytoskeleton associated with cilia. ATG8 gene interference leads to the degradation of IFT88, the transport protein in cilia, thus inhibiting the generation of cilia, and affecting the swing of cilia. This influences the swimming speed and cilia pattern, leading to death in Euplotes amieti.

Garcinia dulcis (Roxb.) Kurz (Clusiaceae) is a medicinal plant native to Southeastern Asia, with a peculiar, precocious pollenkitt production in early microspore development. We aimed to find out whether different secretory activities of the tapetum or a premature sporoderm development provides additional evidence for our recent hypothesis for the precocious pollenkitt production. Histology, histochemistry and ultrastructure of tapetum and sporoderm development during pollenkitt secretion in Garcinia dulcis were conducted, based on light and electron microscopy analysis. The results showed that Garcinia dulcis possesses normal pollen development. The presence of two different pollen coating types, precocious pollenkitt (L1) and common pollenkitt (L2), in the anther tapetum indicate that they are produced in two different active stages of the secretory tapetum. The precocious pollenkitt production and transport to the locule takes place in early active tapetal cells at early tetrad to early microspore stage and is ongoing until late microspore stage. The production of the second type of pollenkitt (L2) starts shortly after the first active tapetum stage together with the formation of sporopollenin precursors. The sporoderm formation was completed at late microspore stage, when the tapetal cell walls start to disintegrate. Orbicules are lining the inner tapetum wall at middle to late microspore stage. ER (during early microspore stage) and plastids (during late microspore stage) were the two main sources of pollenkitt, which finally fused to pollenkitt droplets when the tapetal cells degenerated at mature bicellular pollen stage.

Hydrogen peroxide (H₂O₂) is naturally produced by plant cells during normal development and serves as a messenger that regulates cell metabolism. Despite its importance, the relationship between hydrogen peroxide and the target of rapamycin (TOR) pathway, as well as its impact on cell division, has been poorly analyzed. In this study, we explore the interaction of H₂O₂ with TOR, a serine/threonine protein kinase that plays a central role in controlling cell growth, size, and metabolism in Arabidopsis thaliana. By applying two concentrations of H₂O₂ exogenously (0.5 and 1 mM), we could correlate developmental traits, such as primary root growth, lateral root formation, and fresh weight, with the expression of the cell cycle gene CYCB1;1, as well as TOR expression. When assessing the expression of the ribosome biogenesis-related gene RPS27B, an increase of 94.34% was noted following exposure to 1 mM H₂O₂ treatment. This increase was suppressed by the TOR inhibitor torin 2. The elimination of H₂O₂ accumulation with ascorbic acid (AA) resulted in decreased cell division as well as TOR expression. The potential molecular mechanisms associated with the effects of H₂O₂ on the cell cycle and TOR expression in roots are discussed in the context of the results.

The phytohormone abscisic acid (ABA) is an important regulator of plant growth, but its potential participation in the process of in vitro shoot regeneration has not to date been reported. Here, we found that ABA appeared to inhibit in vitro shoot regeneration. ABA represses the formation of stem cell niches, thereby reducing the shoot regeneration by localizing the expression of WUSCHEL (WUS). During in vitro shoot regeneration, enrichment of H3K9ac in the specific region of WUS is a necessary event for its activation which could be inhibited by exogenous ABA. These findings reveal the potential function, as well as the possible way of ABA in regulating de novo shoot regeneration in Arabidopsis.

Salt-induced stress poses a significant barrier to agricultural productivity by impeding crop growth. Presently, environmentalists are dedicated to safeguarding food security by enhancing agricultural yields in challenging environments. Biostimulants play a crucial role in mitigating abiotic stresses in crop production, and among these, plant essential oils (EOs) stand out as organic substances with diverse biological effects on living organisms. Among the natural promoters of plant growth, Rosmarinus officinalis L. essential oil (RoEO) has gained considerable attention. Although the manifold effects of essential oils (EOs) on plant growth have been extensively demonstrated, their impact on salt stress tolerance in durum wheat seedlings remains unexplored. This investigation was undertaken to evaluate the biostimulatory capabilities of RoEO on the durum wheat cultivar "Mahmoudi." The effects of three RoEO concentrations (1, 2.5, and 5 ppm) on seed germination, growth establishment, and the induction of salt resistance under salinity conditions (150 mM NaCl) were tested. At 5 ppm, RoEO enhanced seedlings' tolerance to salinity by improving growth and reducing membrane deterioration and oxidative stress-induced damage. The expression profile analyses of seven stress-related genes (TdNHX1, TdSOS1, TdSOD, TdCAT, TdGA20-ox1, TdNRT2.1, and TdGS) using RT-qPCR showed enhancement of several important genes in durum wheat seedlings treated with 5 ppm RoEO, even under control conditions, which may be related to salt stress tolerance. The results indicate that the application of RoEO suggests a possible alternative strategy to increase salt tolerance in durum wheat seedlings towards better growth quality, thus increasing ROS scavenging and activation of antioxidant defense.