Immaturin-Nuclease as a Model System for a Gene-Programmed Sexual Development and Rejuvenescence in Life History.

Fertilization-initiated development and adult-onset aging are standard features in the life history of eukaryotes. In , the number of cell divisions after the birth of a new generation is an essential parameter of sexual phase transition and aging. However, the gene driving this process and its evolutionary origin have not yet been elucidated.

Azoreductase from alkaliphilic Bacillus sp. AO1 catalyzes indigo reduction.

Indigo is an insoluble blue dye historically used for dyeing textiles. A traditional approach for indigo dyeing involves microbial reduction of polygonum indigo to solubilize it under alkaline conditions; however, the mechanism by which microorganisms reduce indigo remains poorly understood. Here, we aimed to identify an enzyme that catalyzes indigo reduction; for this purpose, from alkaline liquor that performed microbial reduction of polygonum indigo, we isolated indigo carmine-reducing microorganisms.

Dd-STATb, a Dictyostelium STAT protein with a highly aberrant SH2 domain, functions as a regulator of gene expression during growth and early development.

Dictyostelium, the only known non-metazoan organism to employ SH2 domain:phosphotyrosine signaling, possesses STATs (signal transducers and activators of transcription) and protein kinases with orthodox SH2 domains. Here, however, we describe a novel Dictyostelium STAT containing a remarkably divergent SH2 domain. Dd-STATb displays a 15 amino acid insertion in its SH2 domain and the conserved and essential arginine residue, which interacts with phosphotyrosine in all other known SH2 domains, is substituted by leucine.

Rapid generation of gene disruption constructs by in vitro transposition and identification of a Dictyostelium protein kinase that regulates its rate of growth and development.

We describe a rapid method for creating Dictyo stelium gene disruption constructs, whereby the target gene is interrupted by a drug resistance cassette using in vitro transposition. A fragment of genomic DNA containing the gene to be disrupted is amplified by PCR, cloned into a plasmid vector using topoisomerase and then employed as the substrate in an in vitro Tn5 transposition reaction. The transposing species is a fragment of DNA containing a Dictyostelium blasticidin S resistance (bs(r)) cassette linked to a bacterial tetracycline resistance (tet(r)) cassette.

A STAT-regulated, stress-induced signalling pathway in Dictyostelium.

The Dictyostelium stalk cell inducer differentiation-inducing factor (DIF) directs tyrosine phosphorylation and nuclear accumulation of the STAT (signal transducer and activator of transcription) protein Dd-STATc. We show that hyperosmotic stress, heat shock and oxidative stress also activate Dd-STATc. Hyperosmotic stress is known to elevate intracellular cGMP and cAMP levels, and the membrane-permeant analogue 8-bromo-cGMP rapidly activates Dd-STATc, whereas 8-bromo-cAMP is a much less effective inducer.

The Dictyostelium prestalk cell inducer DIF regulates nuclear accumulation of a STAT protein by controlling its rate of export from the nucleus.

Dd-STATc becomes tyrosine phosphorylated, dimerises and accumulates in the nuclei of Dictyostelium cells exposed to DIF, the chlorinated hexaphenone that directs prestalk cell differentiation. By performing cytoplasmic photobleaching of living cells, we show that DIF inhibits the nuclear export of Dd-STATc. Within Dd-STATc there is a 50 amino acid region containing several consensus CRM1 (exportin 1)-dependent nuclear export signals (NESs).

Cellular Differentiation in Submerged Monolayers of Dictyostelium discoideum: Possible Functions of Cytoplasmic Ca and DIF: (cellular slime mold/differentiation/monolayer culture/Ca /DIF).

Cytoplasmic calcium ion (Ca ) has generally been proposed to be a key factor of numerous cellular processes. Among several agents which might be expected to alter cytoplasmic Ca -concentration ([Ca ] ), unexpectedly Ca -antagonist TMB-8 was found to raise considerably [Ca ] , and inhibited not only the formation of prespore cells, but also their maintenance in the monolayer cultures of Dictyostelium discoideum. This seems to indicate that higher [Ca ] is unfavorable to the prespore differentiation.