The pour plate method of counting bacteria is more precise than the streak plate method, but, on the average, it will give a lower count.

We report the isolation and characterization of a chicken gene, GSX, containing a homeobox similar to that of the goosecoid gene. The structure of the GSX gene and the deduced GSX protein are highly related to the previously described goosecoid gene. The two homeodomains are 74% identical. In the first few hours of chick embryogenesis, the expression pattern of GSX is similar to GSC, in the pos...

We have investigated the role of Bone Morphogenetic Protein 4 (BMP-4) and a BMP antagonist, chordin, in primitive streak formation and neural induction in amniote embryos. We show that both BMP-4 and chordin are expressed before primitive streak formation, and that BMP-4 expression is downregulated as the streak starts to form. When BMP-4 is misexpressed in the posterior area pellucida, primiti...

The fate of cells in the epiblast at prestreak and early primitive streak stages has been studied by injecting horseradish peroxidase (HRP) into single cells in situ of 6.7-day mouse embryos and identifying the labelled descendants at midstreak to neural plate stages after one day of culture. Ectoderm was composed of descendants of epiblast progenitors that had been located in the embryonic axi...

In order to study the bacterial flora of dead-in-shell ostrich chicks, twelve unhatched eggs which did nothave external pipping during the hatching period were transferred to the laboratory of microbiology. The eggshells were accurately disinfected and the embryos were removed and placed in a sterile plate. The surface of each embryo was swabbed with a sterile swab which was also plunged throug...

Scatter factor, a recently characterised protein secreted by certain embryonic fibroblasts, affects cultured epithelial by increasing cell motility, the breakdown of cell junctions and cell scattering. The process of gastrulation in higher vertebrate embryos, during which the primitive streak forms, involves an epithelial-to-mesenchymal transformation resembling the effects of the factor on cul...

This paper describes the microfluidic streak plate (MSP), a facile method for high-throughput microbial cell separation and cultivation in nanoliter sessile droplets. The MSP method builds upon the conventional streak plate technique by using microfluidic devices to generate nanoliter droplets that can be streaked manually or robotically onto petri dishes prefilled with carrier oil for cultivat...

A bottle plate for the cultivation of methanogens or other organisms in a defined pressurized-gas atmosphere was developed. The bottle provides the convenience of an agar streak plate, solves the problem of the water exudate from agar medium, and provides a convenient way of adding or sampling a defined gas atmosphere.

A method is described for the quantitative determination of lipids after separation by thinlayer chromatography: the lipid spots are visualized with a charring spray and the darkness of the spots is determined by measuring the quenching produced when the powder is suspended in a scintillation counting gel containing a radioactive sample. A standard curve produced with 2 to 20 pg of ceramide was...