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Sporulation in Bacillus subtilis is a paradigm of bacterial development, which involves the interaction between a larger mother cell and a smaller forespore. The mother cell and the forespore activate different genetic programs, leading to the production of sporulation-specific proteins. A critical gap in our understanding of sporulation is how vegetative proteins, made before sporulation initiation, contribute to spore formation. Here we present a system, spatiotemporally regulated proteolysis (STRP), which enables the rapid, developmentally regulated degradation of target proteins, thereby providing a suitable method to dissect the cell- and developmental stage-specific role of vegetative proteins. STRP has been used to dissect the role of two major vegetative sigma factors, σ H and σ A , during sporulation. The results suggest that σ H is only required in predivisional cells, where it is essential for sporulation initiation, but that it is dispensable during subsequent steps of spore formation. However, evidence has been provided that σ A plays different roles in the mother cell, where it replenishes housekeeping functions, and in the forespore, where it plays an unexpected role in promoting spore germination and outgrowth. Altogether, the results demonstrate that STRP has the potential to provide a comprehensive molecular dissection of every stage of sporulation, germination and outgrowth., (© 2018 John Wiley & Sons Ltd.)

Five thousand brains inhibiting gametogenesis in Nereis diversicolor and Perinereis cultrifera were extracted with cold methanol, giving a micromolecular fraction containing the whole of the inhibitory activity of the brains. This micromolecular fraction, fractionated (i) on Sephadex G 25 fine and (ii) on Sephadex G 25 superfine, gave an inhibitory peak (P 5) in organ culture. Fraction P 5, purified by high-pressure liquid chromatography, showed an area with the same biological inhibitory activity as the blank brains.

The Fluorochrome Geranine G binds to acidophilic neurosecretory cells and produces red orange fluorescence. Chromolipids and pigments show green fluorescence. This method is easy and sensitive. Fluorescence fading during irradiation is low.

In "worms", up to now only neurohormones produced by neurosecretory cells are known; no endocrine organ has been demonstrated. These neurohormones can be involved in the regulation of asexual reproduction (planarians). But their actions have been essentially studied in annelids (oligochaetes, polychaetes, hirudinae) where it is possible to give evidence of several types of functional regulations: endocrine control of sexual differentiation, gonadotropic action, conditioning of gametes development. The isolation of different neurohormones will allow to study and understand their differential action at the level of target cells and to better perceive the evolution of endocrine functions in the animal kingdom.