Cell-free extracts from several microorganisms, when prepared by methods originally devised for Chlorella pyrenoidosa (Emerson strain 3) and incubated anaerobically with ATP, Mg(2+), and 2, 3-dimercaptopropan-1-ol, are capable of reducing sulfate-(35)S to thiosulfate. These microorganisms include, in addition to C. pyrenoidosa (Emerson strain 3), several other strains of C. pyrenoidosa, Chlorel...

Generating a useful recommendation is only the first step in creating a recommendation system. For the system to have value, the recommendations must be delivered with a user interface that allows the user to become aware that recommendations are available, to determine if any of the recommendations have value for them and to be able to act upon a recommendation. By synthesizing previous result...

in regard to aggregate constitution. The several types of recurrent mutants known to involve change of configuration (such as half-mutants and mass-mutants) correspond with these in frequency of origin and in gametic constitution. The fact that the crossing over which yields them is rare is not surprising since crossing over is regularly found to be reduced in structural heterozygotes in Drosop...

Of recent years there have been considerable contributions to the literature of the photosynthesis in plants. One must mention here the papers of Franck (1) and Stoll (2), who developed the theory proposed by Willst~tter (3), the interesting considerations of van Niel and Miiller (4), and the detailed discussions by Gaffron and Wohl (5) and Emerson (6). The most important of recent experimental...

H E phenomenon of self-sterility is known to be very common among T higher plants. The genetic mechanism in most cases studied seems to be that discovered by EAST and MANGELSDORF in Nicotiana data and N . Sanderae. A single series of alleles, S1, Sz . . . , is involved. The growth of a pollen tube is so much inhibited in a style whose cells contain the same allele that it does not reach the emb...