Selective degradation of mitochondria by autophagy (mitophagy) is thought to play an important role in mitochondrial quality control, but our understanding of which conditions induce mitophagy in ...plants is limited. Here, we developed novel reporter lines to monitor mitophagy in plants and surveyed the rate of mitophagy under a wide range of stresses and developmental conditions. Especially carbon starvation induced by dark-incubation causes a dramatic increase in mitophagy within a few hours, further increasing as dark-induced senescence progresses. Natural senescence was also a strong trigger of mitophagy, peaking when leaf yellowing became prominent. In contrast, nitrogen starvation, a trigger of general autophagy, does not induce strong increases in mitophagy. Similarly, general stresses such as hydrogen peroxide, heat, UV-B and hypoxia did not appear to trigger substantial mitophagy in plants. Additionally, we exposed plants to inhibitors of the mitochondrial electron transport chain, mitochondrial translation and protein import. Although short-term treatments did not induce high mitophagy rates, longer term exposures to uncoupling agent and inhibitors of mitochondrial protein import/translation could clearly increase mitophagic flux. These findings could further be confirmed using confocal microscopy. To validate that mitophagy is mediated by the autophagy pathway, we showed that mitophagic flux is abolished or strongly decreased in atg5/AuTophaGy 5 and atg11 mutants, respectively. Finally, we observed high rates of mitophagy in etiolated seedlings, which remarkably was completely repressed within 6 h after light exposure. In conclusion, we propose that dark-induced carbon starvation, natural senescence and specific mitochondrial stresses are key triggers of mitophagy in plants.
Abbreviations: AA: antimycin A; ATG: AuToPhagy related; ConA: concanamycin A; DIS: dark-induced senescence; Dox: doxycycline; FCCP: carbonyl cyanide-p-trifluoromethoxyphenylhydrazone; GFP: green fluorescent protein; IDH1: isocitrate dehydrogenase 1; MB: MitoBlock-6; Mito-GFP: transgenic Arabidopsis line expressing a mitochondrially targeted protein fused to GFP; mtETC: mitochondrial electron transport chain; OXPHOS: oxidative phosphorylation; PQC: protein quality control; TOM20: Translocase of Outer Membrane 20
The ability to find and consume nutrient-rich diets for successful reproduction and survival is fundamental to animal life. Among the nutrients important for all animals are polyamines, a class of ...pungent smelling compounds required in numerous cellular and organismic processes. Polyamine deficiency or excess has detrimental effects on health, cognitive function, reproduction, and lifespan. Here, we show that a diet high in polyamine is beneficial and increases reproductive success of flies, and we unravel the sensory mechanisms that attract Drosophila to polyamine-rich food and egg-laying substrates. Using a combination of behavioral genetics and in vivo calcium imaging, we demonstrate that Drosophila uses multisensory detection to find and evaluate polyamines present in overripe and fermenting fruit, their favored feeding and egg-laying substrate. In the olfactory system, two coexpressed ionotropic receptors (IRs), IR76b and IR41a, mediate the long-range attraction to the odor. In the gustatory system, multimodal taste sensation by IR76b receptor and GR66a bitter receptor neurons is used to evaluate quality and valence of the polyamine providing a mechanism for the fly's high attraction to polyamine-rich and sweet decaying fruit. Given their universal and highly conserved biological roles, we propose that the ability to evaluate food for polyamine content may impact health and reproductive success also of other animals including humans.
Cell-free mitochondrial DNA (cf-mtDNA) is a marker of inflammatory disease and a predictor of mortality, but little is known about cf-mtDNA in relation to psychobiology. A systematic review of the ...literature reveals that blood cf-mtDNA varies in response to common real-world stressors including psychopathology, acute psychological stress, and exercise. Moreover, cf-mtDNA is inducible within minutes and exhibits high intra-individual day-to-day variation, highlighting the dynamic regulation of cf-mtDNA levels. We discuss current knowledge on the mechanisms of cf-mtDNA release, its forms of transport (“cell-free” does not mean “membrane-free”), potential physiological functions, putative cellular and neuroendocrine triggers, and factors that may contribute to cf-mtDNA removal from the circulation. A review of in vitro, pre-clinical, and clinical studies shows conflicting results around the dogma that physiological forms of cf-mtDNA are pro-inflammatory, opening the possibility of other physiological functions, including the cell-to-cell transfer of whole mitochondria. Finally, to enhance the reproducibility and biological interpretation of human cf-mtDNA research, we propose guidelines for blood collection, cf-mtDNA isolation, quantification, and reporting standards, which can promote concerted advances by the community. Defining the mechanistic basis for cf-mtDNA signaling is an opportunity to elucidate the role of mitochondria in brain-body interactions and psychopathology.
Abstrak Biologi merupakan salah satu bidang ilmu pengetahuan yang diajarkan pada siswa tingkat SMP melalui mata pelajaran IPA Terpadu. Sebagai bidang ilmu yang mempelajari tentang makhluk hidup dan ...lingkungan yang telah diciptakan secara teratur, sistematis, dan kompleks oleh Tuhan, biologi memiliki cakupan yang sangat luas dan kaya. Dalam pembelajaran biologi, metode dan media merupakan komponen penting yang dapat berpengaruh terhadap keberhasilan proses belajar mengajar serta minat siswa. Kajian ini bertujuan untuk menguraikan dan merangkum keterkaitan antara metode dan media bervariasi dengan minat siswa dalam pembelajaran biologi tingkat SMP berdasarkan studi literatur maupun hasil penelitian yang relevan. Hasil kajian menunjukkan bahwa penggunaan metode dan media bervariasi dapat memfasilitasi tercapainya tujuan pembelajaran biologi sesuai dengan karakteristik bidang ilmu & tahap perkembangan siswa SMP, menghasilkan pembelajaran biologi yang menarik sebagai salah satu syarat untuk menumbuhkan minat siswa, dapat meningkatkan minat dan prestasi belajar siswa dalam pembelajaran biologi. Penggunaan metode dan media bervariasi dalam pembelajaran biologi tingkat SMP dapat memfasilitasi siswa yang sedang berada pada tahap formal operational thought dan pemahaman romantik untuk mengembangkan kemampuan kognitif dan minatnya dalam mengeksplorasi kekayaan dan keutuhan dari biologi sebagai suatu ilmu pengetahuan. Penggunaan metode dan media yang variatif juga akan menghasilkan proses belajar yang menarik yang membantu siswa menemukan makna dari materi yang dipelajari sehingga semakin meningkatkan minat, pemahaman konsep, dan prestasi belajar mereka dalam pembelajaran biologi. Abstract Biology is a science field which taught to student of junior high school level through Integrated Science subject. As a science field that studies about living things and environment which have been created regularly, systematically, and complexly by God, biology has a very wide and rich coverage. In learning biology, methods and media are important components that can influence the success of teaching and learning process, and student interest. This study aims to describe and summarize the interrelationships between methods and media varies with student interest in biology’s learning of junior high school based on literature studies and relevant research results. The results of the study indicate that the use of varied methods and media can facilitate the achievement of biology’s learning objectives in accordance with the characteristics of the science field and the stage of development of junior high school students, can create an interesting biological learning as one of the requirements to cultivate student interest, can increase student interest and their achievement in biology. The application of varied methods and media in the junior-level biology learning can facilitate students who are in the formal stage of operational thought and romantic understanding to develop their cognitive abilities and interests in exploring the richness and oneness of biology as a science. It will also produce an interesting learning process which can help students discover the meaning of the material learned so that it will increase their interest, concept’s understanding, and learning achievements in biology.
The genomes of eukaryotes are full of parasitic sequences known as transposable elements (TEs). Here, we report the discovery of a putative giant tyrosine-recombinase-mobilized DNA transposon,
, from ...the model fungus
Previously, we described a large genomic feature called the
block which is notable due to the presence of meiotic drive genes of the
gene family. The
block ranges from 110 kb to 247 kb and can be present in at least four different genomic locations within
, despite what is an otherwise highly conserved genome structure. We propose that the reason for its varying positions is that the
block is not only capable of meiotic drive but is also capable of transposition. More precisely, the
block represents a unique case where the
has captured the
s, thereby parasitizing a resident genomic parasite to become a genomic hyperparasite. Furthermore, we demonstrate that
(without the
) is found in other fungal lineages, where it can be as large as 70 kb. Lastly, we provide experimental evidence that the
block is deleterious, with detrimental effects on spore production in strains which carry it. This union of meiotic drivers and a transposon has created a selfish element of impressive size in
, challenging our perception of how TEs influence genome evolution and broadening the horizons in terms of what the upper limit of transposition may be.
•C/N ratio of different plant litter affected the fungal to bacterial growth ratio.•Litter with high C/N ratio favoured fungal growth.•Decomposition in low pH soil further shifted the growth balance ...to fungi.•Fungal to bacterial growth ratios did not correlate to decomposition rates.
Plant litter represents an important source of nutrients and energy for soil microorganisms, but will also selectively affect which organism group, fungi or bacteria, that will be favoured during decomposition. The balance of fungal to bacterial growth will furthermore be affected by soil chemistry like pH. A laboratory experiment was carried out using two different Mediterranean forest soils differing in pH, adding five types of litter varying in C/N ratio from 15 to 75, including the major litter type from the two soils. Growth of bacteria (using the leucine incorporation technique) and fungi (using the acetate into ergosterol incorporation technique) was then followed during 6 weeks. The balance of fungal to bacterial growth was positively affected by litter with increasing C/N ratio, while the C availability, as judged by evolved CO2, did not have any influence. Furthermore, low pH in the soil further favoured fungal growth, irrespective of the litter type. Despite differences in fungal to bacterial growth this appeared to have little influence on respiration rates from the added litter, suggesting functional redundancy. Our results highlight how both initial soil conditions (pH) and litter composition (C/N ratio) independently affects fungal and bacterial growth during decomposition.
Abstrak: Pengembangan mobile learning mata pelajaran biologi berbasis Science, Technology and Society (STS) menawarkan solusi akibat keterbatasan waktu tanpa menghilangkan keterampilan proses sains ...dalam pembelajaran. Tujuan pengembangan adalah menghasilkan produk mobile learning yang valid dan efektif untuk digunakan dalam pembelajaran. Metode pengembangan ini menggunakan model ASSURE, tahapannya meliputi analyze learner; state objectives; select methods, media and materials, utilize media and materials; require learner participation; evaluate and revise. Instrumen penelitian menggunakan angket tanggapan dari ahli materi, ahli media, uji perorangan, uji kelompok kecil, uji lapangan, dan rubrik penilaian. Berdasarkan analisis data hasil penelitian mobile learning mata pelajaran biologi berbasis STS dinyatakan valid dan efektif untuk digunakan dalam pembelajaran serta domain-domain STS telah tercapai. Abstract: Development of mobile learning based on Science, Technology, and Society (STS) biology subjects offers solutions due to time constraints without eliminating science process skills in learning. The purpose of development is to produce mobile learning products that are valid and effective for use in learning. This development method uses the ASSURE model, the stages include the analyze learner; state objectives; select methods, media, and materials, utilize media and materials; require learner participation; evaluate and revise. The research instruments used questionnaires responses from material experts, media experts, individual tests, small group tests, field tests, and assessment rubrics. Based on data analysis from mobile learning research, STS-based biology subjects are declared valid and effective to be used in learning and STS domains have been achieved.
Self-assembling peptide-based hydrogels are a class of tunable soft materials that have been shown to be highly useful for a number of biomedical applications. The dynamic formation of the ...supramolecular fibrils that compose these materials has heretofore remained poorly characterized. A better understanding of this process would provide important insights into the behavior of these systems and could aid in the rational design of new peptide hydrogels. Here, we report the determination of the microscopic steps that underpin the self-assembly of a hydrogel-forming peptide, SgI37‑49. Using theoretical models of linear polymerization to analyze the kinetic self-assembly data, we show that SgI37‑49 fibril formation is driven by fibril-catalyzed secondary nucleation and that all the microscopic processes involved in SgI37‑49 self-assembly display an enzyme-like saturation behavior. Moreover, this analysis allows us to quantify the rates of the underlying processes at different peptide concentrations and to calculate the time evolution of these reaction rates over the time course of self-assembly. We demonstrate here a new mechanistic approach for the study of self-assembling hydrogel-forming peptides, which is complementary to commonly used materials science characterization techniques.
The challenge of managing aquatic connectivity in a changing climate is exacerbated in the presence of additional anthropogenic stressors, social factors, and economic drivers. Here we discuss these ...issues in the context of structural and functional connectivity for aquatic biodiversity, specifically fish, in both the freshwater and marine realms. We posit that adaptive management strategies that consider shifting baselines and the socio-ecological implications of climate change will be required to achieve management objectives. The role of renewable energy expansion, particularly hydropower, is critically examined for its impact on connectivity. We advocate for strategic spatial planning that incorporates nature-positive solutions, ensuring climate mitigation efforts are harmonized with biodiversity conservation. We underscore the urgency of integrating robust scientific modelling with stakeholder values to define clear, adaptive management objectives. Finally, we call for innovative monitoring and predictive decision-making tools to navigate the uncertainties inherent in a changing climate, with the goal of ensuring the resilience and sustainability of aquatic ecosystems.
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