Caenorhabditis elegans spermiogenesis involves spermatid activation into spermatozoa. Activation occurs through either SPE‐8 class‐dependent or class‐independent pathways. Pronase (Pron) activates the SPE‐8 class‐dependent pathway, whereas no in vitro tools are available to stimulate the SPE‐8 class‐independent pathway. Thus, whether there is a functional relationship between these two pathways is currently unclear. In this study, we found that proteinase K (ProK) can activate the SPE‐8 class‐independent pathway. In vitro spermiogenesis assays using Pron and ProK suggested that SPE‐8 class proteins act in the hermaphrodite‐ and male‐dependent spermiogenesis pathways and that some spermatid proteins presumably working downstream of spermiogenesis pathways, including MAP kinases, are preferentially involved in the SPE‐8 class‐dependent pathway. We screened a library of chemicals, and a compound that we named DDI‐1 inhibited both Pron‐ and ProK‐induced spermiogenesis. To our surprise, several DDI‐1 analogues that are structurally similar to DDI‐1 blocked Pron, but not ProK, induced spermiogenesis. Although the mechanism by which DDI‐1 blocks spermiogenesis is yet unknown, we have begun to address this issue by selecting two DDI‐1‐resistant mutants. Collectively, our data support a model in which C. elegans male and hermaphrodite spermiogenesis each has its own distinct, parallel pathway.

A series of aniline and m-phenylenediamine derivatives with electron-withdrawing 3,3,3-trifluoropropenyl substituents were synthesized as small and chemically stable fluorescent organic compounds. Their fluorescence performances were evaluated by converting 2,4-disubstituted aniline 1 to the non-fluorescent dipeptide analogue H-Gly-Pro-1 for the use as a fluorogenic substrate for dipeptidyl peptidase-4 (DPP-4). The progress of the enzymatic hydrolysis of H-Gly-Pro-1 with DPP-4 was monitored by fluorometric determination of 1 released into the reaction medium. The results suggest that 1 could be used as fluorophore in OFF–ON-type fluorogenic probes.

A series of aniline-based fluorophores were newly synthesized. To increase their fluorescence quantum yields, it was particularly important to substitute 3,3,3-trifluoroprop-1-enyl (TFPE) groups next to the amino group to benefit from an extended π-electron delocalization. Among these, 5-CN-2-TFPE-aniline was found to behave as an excellent fluorophore with a reasonable fluorescence quantum yield of 0.89 even in aqueous solution. l-Alanine peptide, a nonfluorescent analogue of 5-CN-2-TFPE-aniline, was synthesized and successfully employed as an enzyme probe to detect aminopeptidase N activity.

The mol­ecule adopts an E configuration at the C=C double bond. The dihedral angle between the benzene ring and the prop-1-enyl group is 25.4 (3)°. In the crystal, mol­ecules are linked via N—H⋯F hydrogen bonds, forming inversion dimers which are linked into ribbons along the b axis by C—H⋯N hydrogen bonds. The ribbons are linked by N—H⋯π and C—H⋯π inter­actions, generating a three-dimensional network.

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