Protoplasma最新文献

Water is essential for all forms of life, and its loss triggers a series of protective responses in both prokaryotic and eukaryotic organisms. This review summarizes the fundamental mechanisms that underlie desiccation tolerance, focusing on the phenomenon of anhydrobiosis. Key strategies include osmoprotection, accumulation of compatible solutes such as trehalose and sucrose, protein anti-aggregation, and enhanced antioxidant activity. Osmoadaptation enables cells to regulate osmotic pressure and maintain membrane integrity during water loss. Intrinsically disordered proteins, particularly late embryogenesis abundant (LEA) proteins, contribute to protein stabilization by forming molecular shields under desiccation stress. Furthermore, the upregulation of antioxidant enzymes, such as superoxide dismutase (SOD) and catalase (CAT), mitigates oxidative damage to nucleic acids and proteins. Together, these mechanisms preserve cellular integrity and functionality, facilitating recovery upon rehydration.

This study provides a detailed embryological and histochemical analysis of seed development in Miconia crenata, an autonomous apomict, and its sexual congener M. tococa (Melastomataceae). Both species exhibit a nuclear endosperm that is only partially cellularized and is rapidly consumed by the developing embryo. For the first time in Melastomataceae, partial endosperm cellularization was confirmed. Histochemical tests revealed that nucellar cells accumulate polysaccharides, which are gradually mobilized during embryogenesis, indicating that the nucellus contributes nutritionally to embryo growth. In M. crenata, additional embryos can arise adventitiously from cells near the hypostasis. Our findings highlight that the reduced nutritional contribution of the endosperm, combined with the compensatory role of the nucellus, may facilitate the maintenance and evolution of autonomous apomixis in the family, a pattern also seen in Asteraceae. These results expand our understanding of reproductive strategies in angiosperms and the structural basis for autonomous seed development.

Onopordum acanthium L. (Asteraceae), a traditionally used medicinal plant, was investigated for its morphological, phytochemical, and biological properties in this comprehensive study. Methanolic and aqueous extracts were prepared from different parts of the plant (root, stem, leaf, flower, and fruit) and analyzed for their phenolic composition, antioxidant, antidiabetic, anticholinesterase, antimicrobial, and genotoxic activities. LC-MS/MS analysis revealed that chlorogenic acid was most abundant in the flower (3045.38 ng/mL) and root (728.53 ng/mL) aqueous extracts, while quinic acid reached 856.27 ng/mL in the root. Quercetin, apigenin, and luteolin were also detected at significant levels. The fruit methanol extract showed the highest total phenolic (100.78 ± 0.0015 µg GAE/mg), flavonoid (603.67 ± 0.0015 µg RE/mg), and tannin (186.22 ± 0.0015 µg TAE/mg) contents. Antioxidant assays demonstrated notable ABTS^•⁺ (38.38 ± 0.0042%) and DPPH^• (28.43 ± 0.0252%) scavenging capacities in the same extract. Regarding enzyme inhibition, the flower aqueous extract showed the strongest α-glucosidase inhibition (45.58%), while the fruit aqueous extract exhibited moderate α-amylase inhibition (26.33%). The stem methanol extract displayed the highest acetylcholinesterase inhibition (19.02%), whereas the root aqueous extract showed the highest butyrylcholinesterase inhibition (10.76%). Antimicrobial assays revealed moderate antifungal activity, particularly against Candida tropicalis (MIC = 312.5 µg/mL), with the flower and fruit methanol extracts being the most effective. Genotoxicity assessment using Ames and Allium tests confirmed biosafety up to 5 mg/plate and 250 mg/L, respectively, except for flower extracts, which showed slight cytogenotoxicity. Overall, this study highlights O. acanthium as a promising natural source of phenolic compounds with therapeutic potential, particularly in managing oxidative stress, diabetes, and neurodegenerative disorders.

The rice leaffolder, Cnaphalocrocis medinalis, is a major pest threatening rice production, causing significant yield losses. Developing resistant cultivars offers a sustainable and eco-friendly approach to its management. This study aimed to identify leaffolder-resistant rice genotypes and explore associated genomic regions using SSR markers for future marker-assisted breeding. A total of 96 rice landraces were evaluated under both net house and field conditions across two cropping seasons. Based on consistent phenotypic performance, 20 genotypes were classified as resistant, 28 as moderately resistant, and 28 as susceptible. Genetic screening using reported SSR markers for leaffolder resistance revealed high polymorphism, with an average PIC of 0.75 and gene diversity ranging from 0.612 to 0.834. Cluster and structure analysis grouped the genotypes into three major clusters, with most resistant genotypes forming a distinct group. PCA further validated this genetic grouping, effectively separating resistant, moderately resistant, and susceptible genotypes. Additionally, heat map of kinship matrix supported the population differentiation. AMOVA indicated that 86% of total genetic variation was attributed to differences within populations, while 14% was observed among populations. Association analysis using simple linear regression identified three markers viz: RM72, RM48, and RM162, on chromosomes 8, 2 and 6, respectively, linked to leaffolder resistance. Notably, these markers are located near genes, that are involved in rice defense responses against leaffolder as well as other biotic stresses. Overall, the integration of phenotypic and molecular data in this study provides a foundation for marker-assisted selection and provides valuable genomic resources for developing durable leaffolder-resistant rice cultivars.

Diabetes mellitus and Alzheimer's disease are interconnected, with type 2 diabetes raising dementia risk. Decoctions and infusions of Tripleurospermum monticolum (Asteraceae) are traditionally used to treat cough, stomachaches, and fever, while its flowers are commonly brewed into tea to alleviate stomach discomfort. The study examined the inhibitory effects of methanol and aqueous extracts from T. monticolum (capitulum, root, and aerial parts) on key enzymes (acetylcholinesterase, butyrylcholinesterase, α-amylase, and α-glucosidase) and assessed antioxidant activity, as well as the total phenolics, flavonoids, and tannins. Essential oils were analyzed via GC-MS/MS, and morphological, anatomical, and metabolite tests were also performed. In the essential oil of the capitulum, (2Z,8Z)-matricaria ester (64.1%) is the dominant compound, while the aerial part is rich in pentacosane (22.2%) and caryophyllene oxide (13.5%). The root, on the other hand, contains high levels of geranyl isovalerate (30.7%). The aerial part methanol extract showed the highest phenolic (74.686 µg GAE/mg), flavonoid (259.083 µg RE/mg), and tannin (83.000 µg TAE/mg) contents. Root methanol extract had the strongest 2,2-Diphenyl-1-picrylhydrazyl radical (DPPH^•) activity (20.855%), while capitulum methanol extract was most effective in 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS^•⁺) scavenging (9.362%). T. monticolum extracts exhibited antibacterial activity with MIC values ranging from 1250 to 2500 µg/mL, and notable anticandidal effects (MIC = 625-2500 µg/mL), particularly against Candida tropicalis. Additionally, the essential oils from the root and flower demonstrated antifungal efficacy, with MIC values of 625 µg/mL and 1250-2500 µg/mL, respectively. The qualitative analysis revealed alkaloids, flavonoids, and tannins in all samples, while lipids were selectively detected in CM, APM, and RM, showing metabolic variability. T. monticolum exhibited promising antioxidant, enzyme inhibitory, antimicrobial, and phytochemical properties, highlighting its potential as a multifunctional medicinal plant, particularly in the context of diabetes and neurodegenerative disease management.

Plants during their evolution have acquired a highly efficient apparatus comprising several photoreceptor systems, the most effective in the transition from scoto- to photomorphogenesis being the blue-light-absorbing cryptochromes (crys) and the red - far-red-absorbing phytochromes (phys). Within the phytochrome family, the major ones are phyA and phyB, the former one comprising two photochemically and functionally distinct types - light-labile and soluble phyA' and relatively light-stable and amphiphilic phyA″. Cryptochromes are represented by cry1 and cry2. phyB and phyA were shown to interact with cry1, the substrate of their phosphorylation activity, modifying its photoregulatory responses. In this work, with the use of phytochrome fluorescence spectroscopy in vivo, we investigated the possible effects of phyA-cry1 interactions on the state of phyA and its native types, phyA' and phyA″ in etiolated Arabidopsis (Columbia) plants. In cry1 mutant (cry1) and cry1 overexpressor (CRY1OX), the spectroscopic properties and total content of phyA remained practically unchanged as compared to the wild type (WT), whereas the [phyA']/[phyA″] ratio was raised from approximately 0.8-1.0 in the WT and CRY1OX to 1.6 in cry1. This shift in the phyA pools' balance towards phyA' suggests that cry1 hampers the formation of phyA' from phyA″, possibly interfering with the phosphorylation of the latter. cry1 and phyA″ localized in the cytoplasm are likely to be responsible for the induction of the fast membrane depolarization effects (Folta and Spalding 2001), whereas the slow end-point photoregulation reactions may be connected with the nuclear fraction of cry1 interacting with phyA' and/or phyA″.

Breast cancer is a widely studied cancer that involves multiple complex molecular mechanisms in its development and progression. To gain a deeper understanding of the molecular mechanisms of breast cancer and to search for potential therapeutic targets and prognostic markers, we performed an in-depth analysis of breast cancer gene expression data using weighted co-expression network analysis. First, we downloaded breast cancer-related gene expression data from public databases and performed weighted co-expression network analysis. Through the analysis, we identified the purple modules that are closely related to breast cancer and screened out 224 genes for further functional enrichment analysis. To construct the protein interactions network, we selected 90 of these genes for analysis after screening. The GO enrichment analysis mainly focused on the response of extracellular matrix organization to hormones, negative regulation of angiogenesis, positive regulation of cell proliferation, positive regulation of epithelial-to-mesenchymal transition, transforming growth factor β-receptor signaling pathway, localization of proteins to membranes, response to cortisol, positive regulation of protein kinase B signaling, and other biological processes. KEGG pathway enrichment analysis mainly includes PI3K-Akt signaling pathway, TGF-β signaling pathway, cell cycle, proteoglycan in cancer, MAPK signaling pathway, and many other cancer disease pathways. Finally, we screened the key genes in the protein interactions network using Cytoscape's MCODE plug-in and identified nine key markers, namely THBS2, ACTA2, TIMP1, VCAN, TGFB2, FN1, BGN, CCN2, and TAGLN. These genes may play an important role in the pathogenesis of breast cancer providing new ideas for breast cancer treatment and prognosis.

A large set of tRNAs is imported into the plant mitochondria from the cytosol. Besides tRNA import, the mitochondria are capable of uptaking DNA from the cytosol. These two processes may partially overlap, but little is known about which membrane proteins act as carriers for both DNA and RNA. In our work, we studied the role of tRNA carriers in the outer mitochondrial membrane in DNA transfer into the Arabidopsis mitochondria. The outer membrane translocase receptor subunit Tom20-2 and tRNA import-engaged Tric1/Tric2 proteins are involved in the import of short (265 bp), but not long (2.7 kb), DNA fragments. The presence of one of the Tric subunits is sufficient for the normal functioning of the DNA transport channel formed by these proteins. Based on treatment of mitochondria isolated from tric1/tric2 knockout line with antibodies, we suggest that Tric1/2 plays a central role in the import of not only tRNA but also short-length DNA fragments, sharing channel with VDAC1 and Tom40. Thus, our results suggest that Tric1/2 proteins and TOM complex subunits take part in both tRNA and DNA translocation, revealing a new layer of multifunctionality of outer membrane carrier proteins.

Throughout the life of a plant, generations of different forms of reactive oxygen (ROS) and nitrogen species (RNS) are derived as a by-product of metabolic events. The quantum of ROS and RNS becomes higher once a plant encounters a perturbed situation either through biotic or abiotic factor. As each of reactive species is harmful to the cells beyond certain optimal level, it requires a mechanism to detoxify RONS induced cellular toxicity. For the purpose cell has instituted highly organized multi-layered defense mechanisms. In the first layer of defense, cell produces different antioxidant enzymes and non-enzyme molecules. Once generated, ROS and RNS become beyond the detoxification capacity of cellular antioxidant pool, another strategy comes into the operation wherein a few targeted cells undergo self-autolysis progression known as programmed cell death (PCD). The process of PCD has been partially dissected in plants emphasizing either under amplified ROS or RNS condition. However, there are evidences for reaction between species of ROS and RNS. It is unequivocally evident that superoxide has tendency to react with nitric oxide giving rise to a very potential oxidant called peroxynitrite that has ability to nitrosylate several biomolecules thus, altering cellular fate. This suggests that cellular damage caused by reactive species of nitrogen and oxygen is not only an outcome of accumulation of individual species of ROS and RNS, but a combinatorial product of ROS and RNS may have a key role to play. In this review, we intend to advocate role of cellular nitro-oxidative condition in PCD in plants.

Mucilage cells have critical ecological and functional importance, including water storage, transport, and seed protection. These cells can exhibit diverse morphologies, often accompanied by structural changes in the cell wall, which are key to their functionality. In Myrsine umbellata, epidermal mucilage cells exhibit dual secretion: phenolic compounds and mucilage. These contents are separated by a "cell wall"; however, the formation and composition of this wall after cell differentiation remain unclear. Although some studies suggest the presence of an inner cell wall, its development and chemical makeup have not been thoroughly investigated. Using immunocytochemistry and transmission electron microscopy, we found that the new wall forms continuously with the innermost layer of the outer periclinal wall. This new layer resembles primary walls in composition, containing high levels of homogalacturonans (HGs) with a high degree of methyl-esterification, and rhamnogalacturonan I (RG-I) with arabinan side chains. It also includes low concentrations of de-esterified HGs bound to calcium ions and RG-I with galactan side chains. In the mature stage, the new wall also contains higher concentrations of arabinogalactan proteins (AGPs) and cellulose. This newly formed wall compartmentalizes the mucilage cell, isolating the protoplast from the mucilaginous compartment, thus preserving the protoplast and preventing cell death in this idioblast.