Importance of carbon dioxide in the isolation of pneumococci

Austrian, Robert (The University of Pennsylvania School of Medicine, Philadelphia), and Patricia Collins. Importance of carbon dioxide in the isolation of pneumococci. J. Bacteriol. 92:1281-1284. 1966.-Of the strains of pneumococci isolated from man, 8% manifest a requirement for CO(2) if detectable growth is to occur on the surface of solid media. The pneumococci most frequently manifesting this requirement are types I, III, XVI, XXVIII, and XXXIII. These strains will grow in the presence or absence of oxygen provided the atmosphere in which they are incubated contains CO(2). Review of published data provides no unequivocal evidence for the existence of anaerobic pneumococci.     

Failure of spermatozoa from T/t mice to fertilize in vitro is overcome by zona drilling

Failure of epididymal spermatozoa from T/t mutant mice, but not from t/t individuals, to fertilize oocytes in vitro was partially overcome by opening a small aperture in the zona pellucida with acidified Tyrode's solution to permit direct access of the spermatozoon to the vitellus. This study provides a model system to evaluate requirements for successful zona drilling in the treatment of human infertility and further insights into the effects of the t complex on sperm fertility.     

Preparation of microtubules from rat liver and testis: cytoplasmic dynein is a major microtubule associated protein

A microtubule associated protein from brain tissue (MAP 1C), has been found to possess many properties in common with ciliary and flagellar dyneins (Paschal et al.:J. Cell Biol. 105:1273-1282, 1987). However, this protein, now designated as cytoplasmic dynein, exhibited several properties which distinguish it from axonemal forms of the enzyme. We have investigated these characteristics further in a study of cytoplasmic dyneins from non-neuronal tissues. Rat liver and testis in particular were found to contain high levels of cytoplasmic dynein. The yield of dynein from testis was over 70 micrograms/g of tissue, making this the best source of cytoplasmic dynein of all tissues so far examined. The characterization of dynein from these sources has confirmed and extended our previous observations concerning the unique properties of cytoplasmic dynein. Activation of liver and testis dynein occurred at low (less than 1 mg/ml) tubulin concentration. Polypeptides identified as subunits of brain cytoplasmic dynein (74, 59, 57, 55, and 53 kDa) were present in liver and testis preparations. In addition, polypeptides at 150 and 45 kDa were found to copurify with the non-neuronal dyneins. The liver and testis enzyme hydrolyzed pyrimidine nucleotides at rates up to 12.5 times faster than ATP, though the relative affinity of cytoplasmic dynein for CTP was much lower (Km = 1.0 mM) than that for ATP. The properties of the testis enzyme were consistent with its identification as a cytoplasmic dynein rather than a sperm axonemal precursor. These data indicate that cytoplasmic dyneins may be widespread in distribution and that they share certain biochemical properties unique from those of axonemal dyneins. These characteristics are consistent with the proposal that cytoplasmic dynein plays a universal role in retrograde organelle motility.