The continuous production and harvest of uncontaminated cells for periods of several months are a major requirement inthe design of a suitable culture system. Many continuous-culture units have been reported previously (1, 2), and some units are now commercially available. However, in these units, rubber, metals, and other sources of potentially toxic extractives are not prevented from direct c...

A device has been developed to increase and control the cell concentration in continuous culture fermentation reactors. This cell control device, used to study mixed culture methane fermentations, was developed because it is necessary to obtain cell concentrations much higher than can be obtained in a single stage reactor by adjustment of residence time or substrate concencentration. Designed a...

There are innumerable varieties of devices available for the supply of fluid media to continuous culture systems. The unit presented here offers the advantage of being an inexpensive system with a high degree of reliability. No moving parts or pumps are required, and functional models can be constructed from routine laboratory ware. The primary problem with gravity flow or "drip" systems has be...

Sporulation of Bacillus subtilis 168 was studied in chemostat cultures. Sporulation occurred at high frequency under limitation of growth by glucose or the nitrogen source in minimal medium, whereas rates of sporulation were low for Mg'+, phosphate, citrate, or tryptophan limitation. Sporulation was found at all growth rates tested, and the incidence of spores increased with decrease in growth ...

The presence of la-like antigens on human CFU-c and BFU-e is confirmed and a cell type that lacked immediate capacity for granulocytic colony formation but generated CFU-c after brief incubation in simple suspension culture is identified. This pre-CFU-c. and its immediate progeny, was extremely sensitive to killing by anti-la serum with complement. In contrast, anti-la serum plus complement tre...

to study of biological control of charcoal rot of melon caused by macrophomina phaseolina, 187 isolates of fluorescens pseudomonas isolated of rhizosphere and soil of melon plants. then 12 isolates belong to i, iii and v biovars of p. fluorescens and b biovar of p. putida were selected for greenhouse experiments based on inhibition amount. pseudomonas isolates inhibited mycelial growth signific...

A technique is described in which continuous culture is used for the optimization of media in terms of growth-supporting ability. The technique consists of identifying growth-limiting nutrients by observing the reaction of the continuous system to injection of suspected growth-limiting nutrients into the growth vessel.

This course is an attempt to summarise some of the current knowledge of complexity of cognitive processing within the new “natural context” of learning – the computers. Computers are viewed as much more flexible devices for understanding, modeling, guiding and prompting the learner, than it is generally assumed. In order to be efficient educational tools, they have to accommodate both the gener...

Sporulation of Bacillus subtilis 168 was studied in chemostat cultures. Sporulation occurred at high frequency under limitation of growth by glucose or the nitrogen source in minimal medium, whereas rates of sporulation were low for Mg(2+), phosphate, citrate, or tryptophan limitation. Sporulation was found at all growth rates tested, and the incidence of spores increased with decrease in growt...