Protoplasma最新文献

When the journal Protoplasma was founded 100 years ago in 1926, scientists used two different concepts to describe what we would now consider one and the same object: the cell for the membrane-bound structural unit of life, and protoplasm for the living fluid mass or body of the cell. The flourishing of both concepts together dates back to the 1850s, when biologists revised the original cell theory of 1838/39 while also unifying the definition of the cell across plant and animal kingdoms. However, at the beginning of the 20th century a methodological debate over fixation and staining artifacts divided cell researchers in two polarized groups. Cytologists preferred continuing descriptive research on fixed images of chromosomes and organelles, while general physiologists or "protoplasmologists" sought to develop new physical chemical experiments to study living, uninjured protoplasts. This historical essay shows how the journal Protoplasma emerged from one side of these longer debates over the definition of cellular life, and places the origins of the journal in the context of a changing disciplinary landscape of the life sciences in the first half of the 20th century. It also argues that cross-kingdom research in cell biology has been a foundational source of innovation in cell theory's longer history.

Mastigonemes on the anterior flagellum (AF) of flagellated Stramenopiles (which includes diverse organisms such as diatoms, brown algae, oomycetes and others) are tripartite tubular structures. We investigated the functions of mastigonemes in gametes of the brown alga Ectocarpus species 7 strain Ec32 using a mas1 mutant generated by CRISPR-Cas9. Loss of mastigonemes in the mas1 mutant gametes could be confirmed by immunofluorescence microscopy using a specific anti-MAS1 antibody and transmission electron microscopy, showing complete loss of mastigonemes from the AF. High-speed video analysis revealed a drastic reduction in swimming speed in the mas1 mutant gametes compared to wild type gametes, despite an increase in the AF beat frequency. Additionally, waveform analysis indicated larger AF double amplitudes in the mas1 mutant gametes. These results suggested that mastigonemes enhance the AF thrust. The mas1 mutant male gametes fertilized female gametes (wild type strain Ec25). A mas1 mutant female strain was established from the heterozygous sporophyte that developed from such a zygote. Both wild type and the mas1 mutant male gametes could fertilize the mas1 mutant female gametes. Mastigonemes are therefore dispensable for gamete recognition and fusion in the brown alga Ectocarpus.

Smooth muscle tissues exhibit significant functional diversity across various organ systems, but their cellular heterogeneity remains poorly understood. Recent ultrastructural investigations have identified two distinct populations of smooth muscle cells (SMCs), dark and light cells suggesting potential specialization in their roles. This study aims to comprehensively characterize these SMC subpopulations using a detailed morphological approach and histochemical techniques. This study characterizes two morphologically and functionally distinct smooth muscle cell (SMC) populations-light and dark cells-in avian intestinal and pulmonary tissues through comprehensive histochemical (H&E, Giemsa, Mallory/Crossmon's trichrome, silver stain, alcian blue, toluidine/methylene blue, PAS, Orange G) and ultrastructural (TEM) analyses. Light cells, identified by electron-lucent cytoplasm and secretory vesicles, and dark cells, marked by electron-dense cytoplasm and lysosomes, were consistently segregated within the intestinal muscular tunic and bronchovascular walls. Both subtypes contained dense bodies, confirming contractile capacity while suggesting specialized roles-light cells in secretory functions (e.g., extracellular matrix modulation) and dark cells in lysosome-mediated tissue remodeling. In pulmonary tissues, these cells populated the bronchial walls and the arterial tunica media, implicating subtype-specific contributions to airway resistance and vascular tone. The conserved presence of these populations across organs highlights their fundamental role in motility regulation, with clinical relevance to SMC pathologies: light cell dysfunction may underlie secretory disorders (e.g., mucus hypersecretion in asthma), while dark cell abnormalities could drive hypercontractile states (e.g., hypertension, achalasia). These findings establish avian models as powerful tools for investigating SMC heterogeneity, offering insights into phenotype-specific mechanisms in motility diseases and paving the way for targeted therapies that selectively modulate secretory or contractile SMC subpopulations to restore tissue homeostasis.