Sperm from sneaker male squids exhibit chemotactic swarming to CO2.

Behavioral traits of sperm are adapted to the reproductive strategy that each species employs. In polyandrous species, spermatozoa often form motile clusters, which might be advantageous for competing with sperm from other males. Despite this presumed advantage for reproductive success, little is known about how sperm form such functional assemblies. Previously, we reported that males of the coastal squid Loligo bleekeri produce two morphologically different euspermatozoa that are linked to distinctly different mating behaviors. Consort and sneaker males use two distinct insemination sites, one inside and one outside the female's body, respectively. Here, we show that sperm release a self-attracting molecule that causes only sneaker sperm to swarm. We identified CO2 as the sperm chemoattractant and membrane-bound flagellar carbonic anhydrase as its sensor. Downstream signaling results from the generation of extracellular H(+), intracellular acidosis, and recovery from acidosis. These signaling events elicit Ca(2+)-dependent turning behavior, resulting in chemotactic swarming. These results illuminate the bifurcating evolution of sperm underlying the distinct fertilization strategies of this species.

[8-[Bis(carboxymethyl)aminomethyl]-6-bromo-7-hydroxycoumarin-4-yl]methyl moieties as photoremovable protecting groups for compounds with COOH, NH2, OH, and C=O functions.

We introduce a variant of coumarin-based photoactivatable protecting groups and use it exemplarily for caging of a carboxylic acid, an amine, a phenol, and a carbonyl compound. The caged compounds are efficiently photolyzed at long-wavelength UV/vis irradiation. Compared to the corresponding (6-bromo-7-hydroxycoumarin-4-yl)methyl (Bhc) derivatives, the novel coumarin-type caged compounds are distinguished by (i) dramatically increased solubilities in aqueous buffers, (ii) lower pK(a) values of the C7 hydroxyl of the coumarin chromophore, thus permitting efficient photorelease at lower pH, and (iii) higher photolysis quantum yields in the case of photoprotected carbonyl compounds. The primary step of the photocleavages occurs with rate constants of about 10(9) s(-1).

Wavelength-selective photoactivatable protecting groups for thiols.

We developed and characterized efficient, remarkably water-soluble photolabile protecting groups for thiols based on 2-nitrobenzyl and (coumarin-4-yl)methyl chromophores, among them two new ones. The protecting groups allow, due to their different absorption maxima, wavelength-selective photocleavage of binary mixtures of cysteine derivatives protected at the thiol function with various photolabile protecting groups by irradiation with light. The concept was also functional with the two different S-protected cysteine residues in derivatives of the model peptide resact. Selective photolysis could be achieved for the peptides Ac(0)-Cys(1)(BCMACMOC),Cys(8)(7,8BCMCMOC)-resact and Ac(0)-Cys(1)(C4MNB),Cys(8)(BCMACMOC)-resact by irradiation with light of > or = 402 nm or > or = 436 nm wavelength, respectively, followed by irradiation at lambda > or = 325 nm.

Competition between cleavage and decarboxylation in photolysis of alpha-carboxy-2-nitrobenzyl protected cysteine derivatives.

Photolysis of model peptides containing alpha-carboxy-2-nitrobenzyl (CNB) or alpha-carboxy-4,5-dimethoxy-2-nitrobenzyl (CDMNB) protected cysteines in aqueous solution gives the expected 2-nitrobenzyl-type photocleavage and can be accompanied by photodecarboxylation depending on structural aspects.

{7-[Bis(carboxymethyl)amino]coumarin-4-yl}methoxycarbonyl derivatives for photorelease of carboxylic acids, alcohols/phenols, thioalcohols/thiophenols, and amines.

Light-induced release of biomolecules from inactive precursor molecules represents a powerful method to study cellular processes with high temporal and spatial resolution. Here we report the synthesis and photochemistry of a series of {7-[bis(carboxymethyl)amino]coumarin-4-yl}methyl carboxylates, carbonates, carbamates, and thiocarbonates as potential phototriggers for compounds with COOH, OH, NH(2), and SH functions. The compounds are soluble in aqueous buffer, show low fluorescence, and are efficiently photolysed by irradiation with UV/Vis or IR light to release carboxylates, alcohols, phenols, amines, thioalcohols, or thiophenols.