RNA preparations from dark-grown, light-grown, and greening Euglena gracilis have been compared by polyacrylamide gel electrophoresis and by hybridization to Euglena chloroplast DNA. Chloroplast ribosomal RNA is not detected in dark-grown cells; its abundance increases in greening cells over a 72 hr period until the concentration characteristic of light-grown cells is reached. Other RNA species complementary to chloroplast DNA are present in comparable abundance in light-grown, dark-grown, and greening cells.

Autoradiography↗

PubMed1970

The chain growth rate of T4 lysozyme in vitro.

The average interval between attachment of a 30S ribosomal subunit to bacteriophage T4 lysozyme mRNA and the completion of synthesis of lysozyme protein has been measured in vitro. The measured completion times yield rates of polypeptide chain propagation of 1.6 and 3.0 amino acids per second at 25 degrees C and 31 degrees C, respectively.

Carbon Isotopes↗

PubMed1970

Continuous requirement for host P10 protein during bacteriophage T4 infection.

The Escherichia coli 30S ribosomal protein P10, the product of the str gene, known to be involved only in the initiation of protein syntehsis, is required for all bacteriophage T4 protein synthesis.

Bacterial Proteins↗

PubMed1970

LPP-1 infection of the blue-green alga Plectonema boryanum. I. Electron microscopy.

One-step growth and intracellular growth experiments were performed at high multiplicities of the virus LPP-1 during the infection of the blue-green alga Plectonema boryanum. The eclipse period lasts until 4 hr after infection, the latent period terminates at 6 hr, and the rise period continues until 14 to 16 hr after infection. The burst size was independent of multiplicity of infection over the ranges from 1 to 50. The burst size was 3,000 to 5,000 plaque-forming units (PFU) per infectious center or about 200 PFU per cell. Samples for electron microscopy were taken at characteristic times during the lytic cycle. The first sign of viral infection was the invagination of the photosynthetic lamellae at 3 hr after infection. Mature virions were visible at 4 hr. By 6 to 7 hr, many mature intracellular viral particles could be seen, with lysis beginning at 7 hr. By 10 hr after infection, all infected cells contained mature virions. No evidence for mass migration of performed viral precursors was obtained. The invagination of the lamellae could be prevented by the early addition of chloramphenicol, which implies that this process requires protein synthesis.

Centrifugation, Density Gradient↗

PubMed1970

LPP-1 infection of the blue-green alga Plectonema boryanum. II. Viral deoxyribonucleic acid synthesis and host deoxyribonucleic acid breakdown.

Host and viral deoxyribonucleic acid (DNA) metabolism in LPP-1-infected Plectonema boryanum was studied by equilibrium centrifugation in CsCl gradients. Approximately 50% of the host DNA is degraded to acid-soluble material between 3 and 7 hr after infection. Most of the acid-soluble product is reincorporated into viral DNA. Incorporation of exogenous (3)H-adenine into viral DNA can be detected very early after infection (within the first 2 hr), but the bulk of viral DNA synthesis occurs between 6 and 8 hr. Both the breakdown of host DNA and the synthesis of viral DNA require protein synthesis during the first few hours of infection.

Adenine↗

PubMed1970

LPP-1 infection of the blue-green alga Plectonema boryanum. 3. Protein synthesis.

The structural proteins of mature LPP-1 particles and the patterns of protein synthesis after LPP-1 infection have been examined by electrophoresis on sodium dodecyl sulfate polyacrylamide gels. Structural proteins account for 35% of the LPP-1 genome, and proteins that would require about 65% of the total coding capacity have been detected after infection. The major head proteins have molecular weights of 39,000 and 13,000, whereas the major tail protein is an 80,000-molecular-weight species. Host protein synthesis is depressed soon after infection and appears to be entirely shut off by 5 hr. Three classes of viral proteins are distinguished in infected cells, based on their time course of synthesis and their presence in mature virions.

Acrylates↗

PubMed1969