Covalently closed circular deoxyribonucleic acid (DNA) with a molecular weight of 20 X 10(6) was identified in strains of Streptomyces coelicolor A3(2) of various fertility types. Hybridization studies and digestion by various restriction endonucleases indicated that the circular DNAs (pSH1) were identical regardless of the fertility type (UF, IF, or NF) of the strain from which it was isolated...

Recent work towards the completion of a saturated molecular genetic linkage map for the lepidopteran silkworm, Bombyx mori (n = 28), has provided evidence for existing polymorphisms in the inbred strain C108. Two inbred parental strains, p50 and C108, were crossed to produce the F1 (P/C) hybrid offspring. The populations used in this project were comprised of a combination of 29 F2 (F1 x F1) an...

Almost all (about 95%) of the mitochondrial DNA molecules released by Triton X-100 lysis of HeLa cell mitochondria in the presence of 0.15 M salt are associated with a single protein-containing structure varying in appearance between a 10-20 nm knob and a 100-500 nm membrane-like patch. Analysis by high resolution electron microscopy and by polyacrylamide gel electrophoresis after cleavage of m...

A 4.0-kilobase HindIII/EcoRI-cleaved dog genomic DNA fragment was shown to contain the dog insulin gene by restriction mapping using a human insulin cDNA probe. This fragment was subsequently cloned in a lambda vector, and the nucleotide sequence of the dog insulin gene was determined. As in several other species, the insulin gene of the dog is interrupted by two intervening sequences, one of 1...

A genetic transformation system with similarities to those reported for gram-negative bacteria was found to be associated with membrane vesicles of the ruminal cellulolytic genus Ruminococcus. Double-stranded DNA was recovered from the subcellular particulate fraction of all the cellulolytic ruminococci examined. Electron microscopy revealed that the only particles present resembled membrane ve...

The murine monoclonal antibody (mAb) DF3 reacts with a high molecular weight glycoprotein detectable in human breast carcinomas. DF3 antigen expression correlates with human breast tumor differentiation, and the detection of a cross-reactive species in human milk has suggested that this antigen might be useful as a marker of differentiated mammary epithelium. To further characterize DF3 antigen...

A new transposon library constructed in the background of the highly and homogeneously methicillin-resistant Staphylococcus aureus strain COL yielded 70 independent insertional mutants with reduced levels of antibiotic resistance. Restriction analysis with HindIII, EcoRV, EcoRI, and PstI and then Southern hybridization with probes for the transposon and for the femA-femB gene demonstrated that ...

Blood cells from two unrelated individuals whose erythrocytes exhibit respectively N S-s-U- and MN S-s-U- blood group phenotypes were examined by immunoblotting, periodic acid-Schiff (PAS) staining, and Southern blotting. Protein bands characteristic of delta glycophorin (glycophorin B) were absent from the immunoblots of whole erythrocyte lysates when probed with polyclonal glycophorin antiser...

We have examined the stability of the tandemly repeated genes that encode the ribosomal RNA in Coprinus cinereus. These genes are contained within two linked HindIII fragments in a 3.0-Mb chromosome. We monitored the size of these fragments in both mitotic and meiotic segregants using the contour-clamped homogeneous electric field (CHEF) method. No length changes were observed in the smaller Hi...

The genome of Heliothis armigera entomopoxvirus (HaEPV) has been mapped with four restriction endonuclease enzymes (BamHI, HindIII, PstI and XhoI), and its length estimated at 233 kbp. An EcoRI-generated HaEPV genomic fragment hybridized to all fragments identified as genomic termini, providing the first experimental evidence for the presence of terminal repeat elements in an EPV genome. The Ha...