5alpha-Pregna-1,20-dien-3-one and related compounds from a soft coral.

Four unusual pregnane derivatives, 5alpha-pregna-1,20-dien-3-one (1), 1,4,20-pregnatrien-3-one (3), 5alpha-pregn-20-en-3alpha-o1 o-acetate (4), and 5alpha-pregn-20-en-1alpha,3alpha-diol 3-acetate (6) have been isolated from an unidentified soft coral from Canton Island.     

A structural polypeptide of the baculovirus Autographa californica nuclear polyhedrosis virus contains O-linked N-acetylglucosamine.

A structural glycopeptide, gp41, derived from the occluded virus of the baculovirus Autographa californica nuclear polyhedrosis virus was characterized. The peptide specifically bound wheat germ agglutinin but was not recognized by a panel of seven other lectins. Reactivity with wheat germ agglutinin was eliminated by treatment of gp41 with beta-N-acetylglucosaminidase, indicating that N-acetylglucosamine (GlcNAc) was present as terminal residues. gp41 was efficiently galactosylated by galactosyltransferase only in the presence of Nonidet P-40, suggesting that GlcNAc residues are not exposed on the surface of the virion. Metabolic labelling of gp41 with [3H]GlcNAc occurred in the presence of tunicamycin. The carbohydrate was released by alkaline borohydride treatment and comigrated with N-acetylglucosaminitol in descending paper chromatography. The data indicate that gp41 contains single residues of GlcNAc O glycosidically linked to the polypeptide chain. Evidence suggesting that gp41 is located in the region between the envelope membrane and the capsid (defined here as the tegument) of the occluded virus is also presented.     

Aminophylline increases submaximum power but not intrinsic velocity of shortening of frog muscle.

We hypothesized that methylxanthines, such as aminophylline, increase the power developed by submaximally activated frog skeletal muscles by increasing the force developed at any given velocity of shortening. Frog semitendinosus muscles were excised and tested at 20 degrees C in oxygenated control and aminophylline Ringer solutions. Force-velocity relationships were determined and power was calculated from muscles stimulated at frequencies of 80 and 300 Hz. The 300-Hz frequency of stimulation produced a maximum rate of force development. In 50 and 500 microM aminophylline, twitch force increased by 25 +/- 12 and 75 +/- 13%, respectively. Aminophylline did not affect maximum isometric force generation or the shortening velocity at any relative load. At 80-Hz stimulation and in the presence of 500 microM aminophylline, power increased by an average of 11% at 10 of 14 relative loads. At maximum frequencies of stimulation, aminophylline had no effect on any measured parameter. We conclude that aminophylline increases the power developed by submaximally activated frog muscles through an increase in the force generated particularly at the lower velocities of shortening.     

Q fever in maritime Canada.

Only nine cases of Q fever were recorded in Canada in the 20 years prior to 1978. In the 18 months from August 1979 to January 1981 the disease was diagnosed serologically in six patients from the Maritime provinces. All were epidemiologically unrelated and none had been exposed to animals. Five had pneumonia and one had chronic Q fever with probable prosthetic valve endocarditis. Three of the five pneumonia patients presented with signs and symptoms of an acute lower respiratory tract infection and were indistinguishable clinically from other patients with atypical pneumonias. The other two with pneumonia presented with nonresolving pulmonary infiltrates and complained of decreased energy. Four of the five pneumonia patients responded well to treatment with erythromycin; the fifth required two courses of tetracycline. The patient with chronic Q fever had a large amount of cryoglobulins in his serum and evidence of immune complex disease. These cases indicate that Q fever should be considered as a possible cause of atypical pneumonia in Canada.     

Molecular Cloning and Physical Mapping of Restriction Endonuclease Fragments of Autographa californica Nuclear Polyhedrosis Virus DNA

A restriction fragment library containing Autographa californica nuclear polyhedrosis virus (AcNPV) DNA was constructed by using the pBR322 plasmid as a vector. The library, which is representative of more than 95% of the viral genome, consists of 2 of the 7 BamHI fragments, 12 of the 24 HindIII fragments, and 23 of the 24 EcoRI fragments. The cloned fragments were characterized and used to generate physical maps of the genome by hybridizing nick-translated recombinant plasmid to Southern blots of AcNPV DNA digested with SmaI, BamHI, XhoI, PstI, HindIII, and EcoRI restriction endonucleases. This information was used to define our strain of AcNPV (HR3) with respect to other strains for which physical maps have been previously published. The hybridization data also indicate that reiteration of DNA sequences occurs at the HindIII-L and -Q regions of the genome.     

Skeletal muscle fiber regeneration following heterotopic autotransplantation in cats.

Whole 3 g extensor digitorum longus (EDL) muscles of cats were autotransplanted. The EDL muscles were either transplanted without denervation prior to transplantation (normal transplants) or denervated 3 to 4 weeks prior to transplantation (pre-denervated transplants). A few peripheral skeletal muscle fibers survived transplantation but most fibers degenerated and then regenerated as the transplant became revascularized. Both normal and pre-denervated muscles regenerated successfully and by 50 days after transplantation fibers which had reinnervated showed high and low myofibrillar ATPase activity. Compared to controls, the smaller mean fiber cross-sectional area of the transplants was due to the large number of small fibers, but some fibers in the transplant were larger than any fibers observed in the controls. Transplants regained 57 percent of the muscle mass of the controls. Contraction and half relaxation times of transplanted muscles were slower than controls, but peak isometric tetanus tension per cm² of muscle was nearly normal. Fifty to 170 days after transplantation, muscles showed low oxidative capacity and fatigued rapidly.     

Respiratory syncytial virus ts mutants and nuclear immunofluorescence.

A replicated sector-plating procedure was used to isolate 35 induced temperature-sensitive (ts) mutants and one spontaneous ts mutant from a wild-type stock of respiratory syncytial (RS) virus cloned from recent clinical material. Seven of these mutants were ts for plaque formation at 37 degrees C as well as at the restrictive temperature of 39 degrees C. The wild-type strain did not differ markedly from standard laboratory strains of RS virus. It was dependent on exogenous arginine (84 mug/ml) for optimal growth, and was not significantly inhibited by mitomycin C (10 mug/ml). It was sensitive to actinomycin D (2.5 mug/ml) during the early part of the growth phase. A characteristic focal cytopathic effect was obtained in BS-C-1 cells. Staining of infected monolayers by an indirect immunofluorescence procedure revealed a profusion of filamentous processes extending from the plasma membrane, and a similar modification of the surface of infected cells could be visualized by scanning electron microscopy. Filament production was inhibited when certain ts mutants were incubated at 39 degrees C, confirming the virus-specific nature of the phenomenon. Thirty-four of the mutants were classified into three groups by immunofluorescence. Complementation was observed in mixed infection with a single mutant from each group. Nuclear, as well as cytoplasmic, immunofluorescence was detected in RS virus-infected cells using a high-titer bovine anti-bovine RS virus serum. Visualization of nuclear antigen was dependent on the inhibition of cytoplasmic fluorescence obtained when ts mutants in groups I and III were incubated at restrictive temperature.     

Hexokinase isoenzymes in tissues of the adult and developing guinea pig

Changes in the activities and isoenzyme distribution of hexokinase were determined in a number of tissues during the development of the guinea pig. The total activity in the fetal liver showed a large fall during the second half of gestation to reach adult values by term. With normal diet the fetal, neonatal, and adult livers had isoenzymes I and III but little or no detectable IV (glucokinase). The fetal liver had predominantly type I, but the proportion of type III increased during development. The kinetics of the guinea pig isoenzymes were similar to those reported for the rat. Two additional isoenzymes with mobility between I and II were detected in the fetal liver and blood. They appear to have kinetic properties similar to type I. Detectable liver glucokinase activity was induced by glucose administration to adult guinea pigs. The total activity in kidney, brain and skeletal muscle showed a postnatal rise while in the fetal heart it was high and declined after birth. These tissues contained predominantly type I with varying proportions of type III hexokinase. The ratio of particulate-bound to soluble hexokinase varied from tissue to tissue. All except the liver showed a significant increase in binding after birth. The changes are discussed in relation to the control of glucose utilization in the fetal and neonatal periods.     

Factors affecting the yield of virus in a cloned cell line of Trichoplusia ni infected with a nuclear polyhedrosis virus

The TN-368 tissue culture line of the cabbage looper, Trichoplusia ni, has been cloned. The doubling times of three clones at 27°C were 27.6 ± 3.4 hr, 21.9 ± 1.7 hr, and 27.4 ± 5.9 hr and that of the uncloned culture was 15.8 ± 1.5 hr. Growth of cells in all cultures was arrested after infection with a nuclear polyhedrosis virus of T. ni. There was little difference in the yield of polyhedra from cultures of uncloned or cloned cells infected at a multiplicity of infection (m.o.i) = 4. Yields of polyhedra were about the same when a m.o.i. was in the range of 0.01–4.0, but the yield tripled in the range m.o.i. = 20–30. At higher multiplicities, up to m.o.i. = 500 the yield of polyhedra progressively fell. It is concluded that the observed variation in numbers of polyhedra borne by individual cells in culture is not due to genetic variability among cells, nor can it be accounted for as a consequence of differing m.o.i. by virus. It is postulated that variation in polyhedra yield among cells in culture may be due to such factors as (1) strain differences in the virus, (2) the stage in the cell cycle at which a particular cell is present when infected.