Lymphoid cells of the intestinal mucosa with double kappa and lambda specificity in normal man]

The presence of lymphoid cells possessing both kappa and lambda specificities has been observed in the intestinal mucosa of normal subjects. The variability in the number of such cells in different sections of the same sample and in different subjects seems to be a characteristic of this cell population and may reflect the high activity of the immune system in the small intestine.     

DNA sequence encoding the signal peptide of the lambda receptor in E. coli K 12]

A 181 base pairs DNA fragment from E. coli K 12 has been sequenced. This allows determination of the sequence of the signal peptide of the precursor for the lambda receptor, an outer membrane protein.     

RNA fragments rich in G and A nucleotides obligatory for in vitro DNA replication of phages phi-X 174 and lambda]

Evidence was presented that in vitro conversion of single-stranded DNA of phage phi X 174 to the double-stranded replicative form by partially purified DNA-dependent DNA polymerase I requires a specific RNA fragment acting as primer (25-50 nucleotides). RNA fragments highly rich in nucleotides A and G were obtained by partial degradation of E. coli M 500 Sho-R ribosomal RNA with pancreatic ribonuclease. They become covalently bound to the newly synthesized DNA chain of the replicative form of phage phi X 174. These RNA fragments are also required for in vitro replication of lambda phage DNA.     

Construction of derivatives of lambda phage carrying the lamB gene inserted downstream from the promotors of the lactose operon]

The expression of gene lamB, the structural gene for the lambda receptor in E. coli K-12, has been put under the control of the promoter of the lactose operon. This has been done by in vitro recombination using vectors which are derivatives of phage lambda.     

Cooperative non-specific binding of the cyclic adenosine 3'--5'-monophosphate receptor protein (CRP) from Escherichia coli to double-stranded thymus and lambda pgal DNA]

Either free or combined with cAMP, CRP binds cooperatively to double-stranded thymus and lambda pgal DNA. The affinity of CRP for both DNAs in these non-specific interactions is increased by cAMP without noticeable change in the degree of cooperativity. Values of the intrinsic association constant, cooperativity parameter, and site size of DNA were determined from ultracentrifugal investigations under near-physiological ionic conditions.     

Formation of proviruses in acute infection in vitro and in vivo

Summary Formation of DNA proviruses of RNA viruses, Sendai and Newcastle disease, was studied. DNA provirus of NDV was shown to be formed in mouse L-cells and Sendai DNA provirus in Ehrlich ascites carcinoma cells within 2–3 days post infection.