The Raman spectrum of living cells and microorganisms contains highly specific fingerprint‐like signatures, useful in unequivocally identifying different species and interpreting physiological and metabolic responses to environmental stressors. In situ Raman imaging with dedicated highly sensitive instruments can translate selected spectroscopic fingerprints into vivid snapshots of molecular species or specific physiological reactions. Time‐lapse experiments, crucial in characterizing growth‐dependent phenomena and metabolic response to drugs or substrates, are possible because Raman imaging is life compatible. This review covers miscellaneous examples of Raman analyses and imaging of eukaryotic cells, bacteria, and viruses. Fundamental microbiological analyses covered here include (i) identification of different species of cells, bacteria, and viruses; (ii) characterization of the metabolic responses of cells and bacteria to different substrates; (iii) time‐lapse analyses of cell metabolic reactions upon viral inoculation; (iv) chemical imaging of axon sprouting in neuronal cells; and (v) visualization of the myelinating activity of living Schwann cells in coculture with neuronal cells. The spectroscopic findings displayed here, which are based on a machine learning approach applied to Raman analysis and imaging, demonstrate the invaluable potential for Raman spectroscopy in biophysics research.

While the reciprocity between bioceramics and living cells is complex, it is principally governed by the implant’s surface chemistry. Consequently, a deeper understanding of the chemical interactions of bioceramics with living tissue could ultimately lead to new therapeutic strategies. However, the physical and chemical principles that govern these interactions remain unclear. The intricacies of this biological synergy are explored within this paper by examining the peculiar surface chemistry of a relatively new bioceramic, silicon nitride (Si₃N₄). Building upon prior research, this paper aims at obtaining new insights into the biological interactions between Si₃N₄ and living cells, as a consequence of the off-stoichiometric chemical nature of its surface at the nanometer scale. We show here yet unveiled details of surface chemistry and, based on these new data, formulate a model on how, ultimately, Si₃N₄ influences cellular signal transduction functions and differentiation mechanisms. In other words, we interpret its reciprocity with living cells in chemical terms. These new findings suggest that Si₃N₄ might provide unique new medicinal therapies and effective remedies for various bone or joint maladies and diseases.

Summary: Rice prolamins, a group of seed storage proteins, are synthesized on the rough endoplasmic reticulum (ER) and form type I protein bodies (PB‐Is) in endosperm cells. Rice prolamins are encoded by a multigene family. In this study, the spatial accumulation patterns of various prolamin species in rice endosperm cells were investigated to determine the mechanism of formation of the internal structure of PB‐Is. Immunofluorescence microscopic analysis of mature endosperm cells showed that the 10 kDa prolamin is mainly localized in the core of the PB‐Is, the 13b prolamin is localized in the inner layer surrounding the core and the outermost layer, and the 13a and 16 kDa prolamins are localized in the middle layer. Real‐time RT‐PCR analysis showed that expression of the mRNA for 10 kDa prolamin precedes expression of 13a, 13b‐1 and 16 kDa prolamin in the developing stages. mRNA expression for 13b‐2 prolamin occurred after that of the other prolamin species. Immunoelectron microscopy of developing seeds showed that the 10 kDa prolamin polypeptide initially accumulates in the ER, and then 13b, 13a, 16 kDa and 13b prolamins are stacked in layers within the ER. Studies with transgenic rice seeds expressing prolamin–GFP fusion proteins under the control of native and constitutive promoters indicated that the temporal expression pattern of prolamin genes influenced the localization of prolamin proteins within the PB‐Is. These findings indicate that the control of gene expression of prolamin species contributes to the internal structure of PB‐Is.

We found novel vesicles derived from rough endoplasmic reticulum (ER) in rice endosperm. The novel vesicles had characteristic structures different from that of the ER-derived protein body type I and the Golgi-derived dense vesicles. Immunocytochemical analysis revealed that the novel vesicles are derived directly from the aggregates of vacuolar storage proteins in the rough ER. In addition, BiP, an ER-resident molecular chaperone, was localized in the novel vesicles, but also in protein storage vacuoles (PSVs). These results suggest that the novel vesicles mediate transport of vacuolar storage proteins directly from the ER to PSVs in rice endosperm.