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H J Morowitz

Publications and source records attributed to H J Morowitz.

191 records · Page 11Linked to original sources
PubMed1966

Analysis of the life cycle of Mycoplasma gallisepticum.

Morowitz, Harold J. (Yale University, New Haven, Conn.), and Jack Maniloff. Analysis of the life cycle of Mycoplasma gallisepticum. J. Bacteriol. 91:1638-1644. 1966.-A series of electron microscope observations on Mycoplasma gallisepticum strain A5969 have been made by use of thin-section techniques and negative staining. The methods presented a consistent picture of a postdivision cell, which contains a fibrillar nuclear region, surrounding ribosomal region, highly organized bleb at one end of the cell, granular infrableb region, and bounding unit membrane. Cell division commenced with the appearance of a second infrableb area at the end of the cell opposite the original bleb. A new bleb grew in this area, and the cell then elongated. The nuclear material segregated into two parts separated by a band of ribosomes. A constriction appeared, in this central ribosome-packed area, leading to the formation of two daughter cells. The following was noted: the cells were very small (volume, 5 x 10(-14) cm(3)); each cell was highly structured and strongly ordered; and the replication appeared to be a very precisely programmed series of events.

Cell Division↗
PubMed1965

Ultrastructure and Ribosomes of Mycoplasma gallisepticum.

Maniloff, Jack (Yale University, New Haven, Conn.), Harold J. Morowitz, and Russell J. Barrnett. Ultrastructure and ribosomes of Mycoplasma gallisepticum. J. Bacteriol. 90:193-204. 1965.-The ultrastructure of Mycoplasma gallisepticum strain A5969 has been studied by electron microscopy (thin-section and negative staining), ultracentrifugation, and chemical analysis. The list of ultrastructure is: membrane, nuclear material, ribosomes, ribosomal structures, infra-bleb region, and blebs. The nuclear material, containing the cell's deoxyribonucleic acid, appears as an unbounded region containing 30-A fibrils. The ribosomes have a diameter of about 140 A, a ribonucleic acid-protein ratio of 0.68, and an uncorrected sedimentation coefficient of 70.2S. The 70.2S particle can be broken into 49.3S and 32.4S particles. Ribosomal arrays were found filling the intracytoplasmic space between the nuclear material and the membrane. Under certain conditions, these arrays formed cylindrical arrangements of ribosomes. The infra-bleb region is composed of a granular material, although little internal structure could be found. The bleb was highly structured.

Journal Article↗
PubMed1963

USE OF POROUS CELLULOSE ESTER MEMBRANES IN THE PRIMARY ISOLATION AND SIZE DETERMINATION OF PLEUROPNEUMONIA-LIKE ORGANISMS.

Morowitz, Harold J. (Yale University, New Haven, Conn.), Mark E. Tourtellotte, and Mary E. Pollack. Use of porous cellulose ester membranes in the primary isolation and size determination of pleuropneumonia-like organisms. J. Bacteriol. 85:134-136. 1963.-Millipore filters were used in the primary isolation and sizing of a number of strains of pleuropneumonia-like organisms (PPLO). Maximal pore diameters were checked by filtration of viruses of known sizes. All the PPLO strains studied produced cells capable of passing through a 0.22-mu filter. A number of strains produced forms which could be titered after filtration through a 0.1-mu filter. A number of primary isolations were made from filtrates.

Journal Article↗