The sexual pheromone of Volvox carter-i elicits drastic changes in the synthesis of extracellular sulfated glycoproteins. Synthesis of at least two sulfated glycoproteins is turned on. Induction of this synthetic capacity is as sensitive to the pheromone (-10-i6M) as the overall process of sexual induction. The earliest response, detectable a few minutes after the application of the pheromone, ...

Volvox rousseletii is a multicellular spheroidal green alga containing ∼5,000 cells, each equipped with two flagella (cilia). This organism shows striking photobehavior without any known intercellular communication. To help understand how the behavior of flagella is regulated, we developed a method to extract the whole organism with detergent and reactivate its flagellar motility. Upon addition...

Volvox offers a unique opportunity to study the segregation of reproductive potential during development of a multicellular organism. At the sixth cleavage division of an asexual embryo of Volvox carteri, strain HK 10, one half of the 32 cells typically cleave unequally to yield 16 large gonidial (reproductive) initials and 16 smaller somatic initials, while the remaining cells divide equally t...

Flows generated by ensembles of flagella are crucial to development, motility and sensing, but the mechanisms behind this striking coordination remain unclear. We present novel experiments in which two micropipette-held somatic cells of Volvox carteri, with distinct intrinsic beating frequencies, are studied by high-speed imaging as a function of their separation and orientation. Analysis of ti...

The gls genes of Volvox are required for the asymmetric divisions that set apart cells of the germ and somatic lineages during embryogenesis. Here we used transposon tagging to clone glsA, and then showed that it is expressed maximally in asymmetrically dividing embryos, and that it encodes a 748-amino acid protein with two potential protein-binding domains. Site-directed mutagenesis of one of ...

conclusions the streptomyces sp. suk 25 culturing was optimized using thronton media, at ph 7 and aeration of 140 rpm. further isolation and identification of bioactive compounds will develop anti-mrsa therapeutics. materials and methods disc diffusion and minimum inhibitory concentration (mic) assay were used to determine the antibacterial activity of streptomyces sp. isolates. optimization of...