Protoplasma最新文献

Humic acid (HA) is a redox-active organic compound that can regulate cell metabolism to produce antioxidant metabolites against oxidative stress. Haematococcus lacustris is a green microalga and is found to be a rich source of astaxanthin. In this research, the impact of HA was studied on the growth mechanisms and production of antioxidant metabolites through dynamic responses of pigments, proteins, carbohydrates, secondary messengers of H₂O₂ and Ca²⁺, gamma-aminobutyric acid (GABA), and enzyme activities in H. lacustris. Results revealed that HA at 80 µM concentration is a suitable treatment to induce astaxanthin production and cell growth. Cell numbers increased significantly under HA80, and the trend was to enter the red aplanospore phase at the stationary growth phase. High HA concentration (120 µM) increased astaxanthin content but considerably reduced cell number and size. HA80 enhanced astaxanthin (5.39 mg L^-1), flavonoid (15.64 mg g^-1 DW), and phenolic (55.64 mg g^-1 DW) contents after 9 days of induction time, which was accompanied by a significant reduction in the chlorophyll pigments, proteins, and carbohydrate contents. The increase in total phenolic content was associated with enhanced phenylalanine ammonia-lyase activity. H₂O₂ accumulation decreased by HA80 at the late stationary growth phase. Putrescine and spermidine contents were promoted under HA80, while gamma-aminobutyric acid (GABA) and Ca²⁺ contents were reduced from the logarithmic phase to the early stationary growth phase. Succinate dehydrogenase (SDH) activity was promoted in the TCA cycle, and the GABA shunt was activated to regulate the ROS level. Findings indicate that the impact of HA on cell growth and astaxanthin production is associated with HA concentration and cell growth phase. HA can regulate ROS levels at the stationary growth phase by inducing polyamine metabolism and an antioxidant defense system.

Spores of fungi and seedless plants, and pollen grains of seed plants, are usually characterized by variable global patterns on the surface. However, the mechanisms responsible for the development of these patterns have not been fully understood. We hypothesize that the global pattern of a spore or pollen grain is induced by the stresses resulted from the mismatch between a faster-growing outer part and a slower-growing inner part within the grain and tried to verify the hypothesis by simplifying the developing spores and pollen grains as stressed core/shell structures, simulating the buckling patterns of such structures with different shapes and shell thicknesses through finite element method, and comparing the simulated models with natural spores and pollen grains observed under microscopes. Totally, 313 models were simulated and 77 natural instances were studied. The simulated models reproduced various global patterns generally corresponding to the natural instances from a mechanical point of view. Our findings suggest that stress-driven development potentially contributes to the global patterning of spores and pollen grains, with the shape and thickness of the faster-growing outer part at the beginning of the differential growth determining the pattern types, providing new insights into the development and evolution of the global patterns on spores and pollen grains.

In adult bees, the foregut-midgut transition is marked by the proventriculus, which consists of an anterior muscular bulb extending into the crop lumen and a posterior stomodeal valve in the midgut lumen. In larvae, the proventricular bulb is absent and forms only during metamorphosis, a process that remains poorly understood. This study aimed to describe the cellular events involved in the formation and differentiation of the honey bee Apis mellifera proventriculus during metamorphosis. The foregut-midgut transition of larvae, pupae, and newly emerged adults was analyzed using histology and immunohistochemistry to detect apoptosis, autophagy, cell proliferation, and differentiation. In larvae, the proventriculus consists solely of the stomodeal valve, which disappears in prepupae as the foregut-midgut passage closes. The proventricular bulb precursor emerges in prepupae as a thick epithelium, differentiating alongside the muscle layer until the brown-eyed pupal stage. The stomodeal valve forms in brown-eyed pupae through epithelial invagination towards the foregut lumen and everts in the end of black-eyed pupae stage, projecting into the midgut. Apoptosis was frequent in prepupae but rare in later stages. Autophagy occurred in white- and brown-eyed pupae but was absent in black-eyed pupae. Cell proliferation was observed in prepupae, white- and brown-eyed pupae but not in pink-eyed pupae, where differentiation predominated. No cellular events were detected in black-eyed pupae, marking the end of proventriculus remodeling. The morphogenesis of the A. mellifera proventriculus involves extensive tissue remodeling, with apoptosis, proliferation, and differentiation driving its transformation during metamorphosis.

This study investigates the role of circDCAF6 in regulating the proliferation and apoptosis of bovine myoblasts, focusing on its interaction with bta-miR-196a and IGF2BP3. Using online prediction tools like TargetScan and miRanda, we identified circDCAF6 as a target for bta-miR-196a, bta-miR-196b, and bta-miR-219-3p. Experimental results showed that interference with circDCAF6 significantly increased the expression of bta-miR-196a and miR-196b, while miR-219-3p levels remained unchanged. Following these findings, we confirmed the direct targeting relationship between circDCAF6 and bta-miR-196a using a dual luciferase reporter system and RNA pull-down experiments. Subsequent analysis revealed that circDCAF6 co-transmutation with bta-miR-196a countered the inhibitory effect of the bta-miR-196a mimic on cell proliferation marker genes (CCNA1, CCNA2, MCM6) and restored S-phase cell proportions. Additionally, circDCAF6 diminished the pro-apoptotic effects of bta-miR-196a by reducing apoptosis marker gene expression (Caspase3, Caspase6) and the proportion of early apoptotic cells. We also identified IGF2BP3 as a target of bta-miR-196a, with verification through dual luciferase assays, RT-qPCR, and Western blots. Further research indicated that interfering with IGF2BP3 significantly reduced cell proliferation and increased apoptosis, characterized by lower expression of proliferation markers and higher levels of apoptosis markers. Co-transfer experiments of siRNA for circDCAF6 and IGF2BP3 showed that circDCAF6 could mitigate the inhibitory effects caused by IGF2BP3 interference. In summary, this study highlights the critical role of circDCAF6 in bovine myoblast proliferation and apoptosis via the bta-miR-196a/IGF2BP3 axis, offering insight into muscle development and disease mechanisms.

This study aims to understand the effect of inoculation by arbuscular mycorrhizal fungi Glomus intraradices (AMF) on the regulation of carbon and nitrogen sensibility and the antioxidant system in Sorghum bicolor (L.) Moench plants under lead (Pb) stress (750 ppm). Plant morphology, accumulation of lead, IAA, H₂O₂, MDA, and chlorophyll contents were assayed. The enzymes involved in the carbon/nitrogen interaction as well as the antioxidant enzymes were evaluated via a two-factor pot experiment (inoculation by AMF and stress by Pb). AMFs attenuate Pb damage by upregulating the antioxidant system: superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione s-transferase (GST), and glutathione reductase (GR). Similarly, the activity of each of the key enzymes responsible for the interaction of nitrogen and carbon metabolic pathways, glutamine synthetase (GS), glutamate dehydrogenase (GDH), phosphoenolpyruvate carboxylase (PEPC), and aspartate aminotransferase (AAT), were measured and showed a significant increase in mycorrhizal plants. AMF inoculation decreased H₂O₂ and MDA content and increased the indole acetic acid (IAA) content, which indicates that mycorrhizal inoculation has a great ability to attenuate Pb resistance. Pb stress also negatively affected plant growth by disrupting carbon and nitrogen enzymatic pathways as well as the antioxidant system. Therefore, inoculation with AMFs reduced Pb fullness by decreasing its accumulation in sorghum leaves and roots and regulating the enzymatic system involved in plant growth.

Sands are a harsh habitat with limited water and nutrients, and danger of burial or mechanical injury by moving particles. Sand entrapping plants (psammophytes) actively fix sand on their surfaces, which presumably offers adaptive benefits, such as mechanical protection and camouflage. This short article deals with the structural-functional aspects of sand-trapping in the annual psammophyte Ifloga spicata (Asteraceae). Ifloga spicata outer surfaces are entirely covered with a dense coating of particles, mainly sand and dust. The leaves are needle-shaped and curled with the adaxial surface hidden inside. The entire outer epidermis is secretory, comprised of large cells with thick pectinaceous cell walls and upper cell wall junctions with numerous wall creases. Ruthenium red staining of fresh hand sections of the leaf demonstrated that the outer epidermal cells produce a pectinaceous substance, which upon wetting ruptures outside the cell, resembling pectin "rays" in the Arabidopsis seed coat. TEM imaging showed vesicles arriving at the plasmalemma, fusing with it and the secretory product accumulated in periplasmic spaces inside the cell wall. Ifloga spicata and other sand entrapping plants live in nutrient poor habitats. Foliar particle capture could have an additional benefit of phosphorus accumulation from leaf deposited dust particles, as known in several Mediterranean origin plants.

MicroRNAs (miRNAs) are a class of non-coding RNAs (ncRNAs) that negatively regulate gene expression at the post-transcriptional level. Intramuscular fat (IMF) deposition in livestock is crucial for meat quality, affecting the meat's taste and tenderness. However, there has been little research on the miRNA transcriptome of yak in relation to intramuscular fat deposition in yak. In this study, RNA sequencing in the longissimus dorsi (LD) muscle samples was conducted to uncover the miRNAs expression profiles of yak at two ages: 3 months (calf) and 3 years (adult). A total of 1030 known miRNAs and 279 novel miRNAs were identified, of which 40 differentially expressed miRNAs (DE-miRNAs) were screened. We then obtained target genes of 40 DE-miRNAs and established enrichment analyses using Gene Ontology (GO) and the Kyoto Encyclopedia of Genes Genomes (KEGG). We found target genes were involved in four significantly enriched pathways, and the MAPK signaling pathways were the key pathways. Moreover, we constructed a miRNA-mRNA regulatory network to visualize the functions of miRNAs related to IMF deposition in the yak. miR-122, miR-375, and miR-378 may play a key role in IMF deposition in the yak, and RORC, STAT3, ACACA, FTO, and FOXO1 were the core target genes. We randomly selected six miRNAs from DE-miRNAs to validate the sequencing results using RT-qPCR. This study revealed miRNAs expression profiles in yak IMF development between calf and adult and provided a miRNA database for further studies on the molecular mechanisms of IMF deposition in the yak.

Dengue virus (DENV) is a substantial global health threat with no specific antiviral treatment available. The development of effective vaccines is crucial to combat DENV infections. Plant-based expression systems, such as tobacco chloroplasts, have emerged as promising platforms for the production of DENV antigens. In this research article, we describe the construction of a tobacco chloroplast vector with novel insertion sites for DENV-1 protein III. Our present study successfully demonstrated the production of the envelope protein structural domain III (EDIII) dengue virus antigen in tobacco chloroplasts. We obtained transformed tobacco lines that show the expression of EDIII dengue antigen and were confirmed through Southern blotting analysis. Furthermore, the expression of EDIII antigen was further confirmed via immunoblotting and quantified. These findings suggest that tobacco chloroplast engineering holds promise as a method for future manufacture of an oral dengue boost vaccine that is safe, affordable, and effective, contributing to the global management and control of this particular dengue infection.

Plasmodesmata (PD) are nano-channels in plant cell walls that connect adjacent cells, facilitating the symplastic transport of micro- and macromolecules. In certain tissues, specialized transport requirements drive the formation of intercellular channels in diverse morphologies, compositions and functions, including sieve plate pores, plasmodesmo-pore units, lateral sieve area pore, and flexible gateways. These channels, derived from PD, are referred to as PD-derived intercellular gateways (PdIGs) in this review. Studies of PD and PdIGs are crucial for understanding how plants achieve cell-to-cell and long-distance transport of specific cargos under various physiological conditions. Multiple types of specialized microscopy are essential for studying these nano-channels, enabling elucidating their structures, compositions, distribution patterns, frequencies, and permeability. In particular, transmission electron microscopy (TEM), scanning electron microscopy (SEM), laser scanning confocal microscopy (LSCM), and structural illumination microscopy (SIM) offer advantages for such specialized analysis. With the aid of antibodies, fluorescent dyes, custom-built molecules, and image processing technologies, microscopy can also capture dynamic details of PD/PdIGs beyond morphology features. This review examines the application of these microscopy in studying specific aspects of PD/PdIGs, discusses the merits and limitations of these methods, and evaluate their suitability in PD studying the results obtained from these microscopy studies enhance our knowledge of PD/PdIGs and form the basis of the current paradigm of PD-based plant communication.

Salinity is one of the major abiotic constraints impairing barley production. Tunisian landraces constitute a valuable reservoir of useful traits for breeding programs. Therefore, exploring the molecular mechanisms underlying salinity tolerance is of great interest. Here, the proteome response to salt stress of the 4th leaf at the tillering stage was assessed in two barley accessions, Barrage Mellegue (BM, tolerant) and Saouef (S, sensitive). Results led to the selection of differentially abundant proteins (DAP), including 20 and 49 genotype specific salt responsive proteins, respectively, and 12 common ones. Moreover, 10 biological functions were associated to salinity response, including photosynthesis. Indeed, the RBCS protein was surabundant only in the tolerant genotype. Nevertheless, 8 proteins including PSB28, PPD3, TLP16.5, MgCh40, TLP17.4, Rubisco, OEE and PSBH were less abundant in the sensitive genotype, although invariable in the tolerant BM. Therefore, signaling, nucleic acid binding, protein synthesis, ROS scavenging and photosynthesis might be the main biological processes related to salinity tolerance in barley. In fact, based on hierarchical classification and protein-protein interactions, ES2A, Cp31 BHv, PRX II, Srpsus2, RBCS and RLP12 (RPS50) proteins were identified as key candidates. Our findings suggest that BM can mitigate the negative effect of salinity at the tillering stage by inducing signal transduction pathway elements, reducing nucleic acid binding process, regulating ROS scavenging system, decreasing protein synthesis and, maintaining the photosynthesis system. Our results would serve as a useful source for deciphering the mechanisms governing salt stress tolerance at all stages of development, which is essential for barley breeding programs.