Successful infection of the common marmoset (Callithrix jacchus) with human varicella-zoster virus.

The common marmoset, Callithrix jacchus, can be infected with human varicella-zoster virus (VZV), both wild-type strain KMcC and attenuated vaccine strain Oka/Merck. Infection was accomplished with either whole-cell-associated or cell extract VZV by combined oral-nasal-conjunctival application and was characterized by substantial and persistent anti-VZV antibody responses. The infectivity of VZV for marmosets was destroyed by treatment of inocula with heat or UV light. Diluted inocula with as few as 40 PFU/ml were infectious for marmosets. The lungs were demonstrated to be a major site of viral replication; both the presence of viral antigens and signs of pneumonia were demonstrated in lung tissues. Four serial passages of VZV KMcC were carried out in C. jacchus by a process of in vitro isolation and culturing of VZV from infected lung tissue and reapplication of the cultured isolates to fresh animals. The isolated viruses were identified as VZV both serologically and by restriction endonuclease analyses. The C. jacchus infectivity model should prove useful for determining the efficacy of subunit and live recombinant VZV vaccines as well as for the study of zoster.     

Effect of high temperature on calcium uptake by suspension-cultured pear fruit cells

Uptake of Ca²⁺ by suspension-cultured pear (Pyrus communis L. cv Passe Crassane) cells and protoplasts was significantly enhanced by exposure to 38°C compared to 25°C. The increased uptake was specific for Ca²⁺ and was not due to cell wall binding. Tissues pretreated at 38°C showed increased uptake even upon return to 25°C. Treatment with carbonylcyanide m-chlorophenylhydrazone, salicylhydroxamic acid + KCN, or arsenite also increased Ca²⁺ content of cells. Results are discussed with regard to membrane permeability changes, the cellular control of Ca²⁺, and heat treatments used to inhibit softening of fruit during postharvest storage.     

Suppressed in vitro blastogenic responsiveness of rat spleen cells after continuous infusion of endotoxin by an implanted osmotic pump

Continuous infusion of a gram-negative bacterial endotoxin in relatively small doses into rats by means of an implanted osmotic pump was studied. The model system was designed to examine the effects of endotoxin on the blastogenic response of spleen cells to the endotoxin itself and to a nonspecific T-cell mitogen, concanavalin A (Con A). Rats were implanted with an osmotic pump which delivered saline for the first 42 hr to provide postsurgical recovery before the onset of endotoxin infusion. Previous studies had shown that during the first 1-4 days after administration of endotoxin marked alterations of metabolism and some changes in physiologic parameters such as blood pressure and in vitro myocardial performance occurred. In the present study the blastogenic responsiveness of spleen cells to endotoxin itself as well as to the nonspecific T-cell mitogen Con A was markedly decreased after several days of continuous administration of endotoxin. Control animals receiving only saline for the same period of time showed a similar depression of blastogenic responsiveness to the lipopolysaccharide (LPS), as well as to Con A, however, with a delay of 2-4 days before comparable levels of suppression became evident. These results indicate that marked alterations of immune competence as measured by blastogenesis of spleen cells to Escherichia coli LPS and to a mitogen such as Con A may occur after implantation of an osmotic pump, with or without continuous infusion of endotoxin. Further studies seem warranted to determine the role of the foreign body reaction to the osmotic pump as well as to the endotoxin administered by the pump.     

Proteoglycan metabolism associated with mouse metanephric development: morphologic and biochemical effects of beta-D-xyloside

Morphology and de novo incorporation of [35S]sulfate into proteoglycans were studied in fetal mouse kidneys at the onset of organogenesis. Branching morphogenesis and nephron development in organ culture and in vivo were associated with de novo synthesis of chondroitin-SO4 and heparan-SO4 proteoglycans. The role of proteoglycan metabolism in metanephrogenesis was then studied by analysis of the effects of p-nitrophenyl-beta-D-xylopyranoside (beta-D-xyloside) on renal development and proteoglycan metabolism. Incubation of fetal kidneys in beta-D-xyloside at concentrations of 1.0 and 0.5 mM, but not at 0.1 mM, caused inhibition of ureteric branching and markedly diminished synthesis of a large Mr 2.0 X 10(6) Da chondroitin-SO4 proteoglycan. Incorporation of [35S]sulfate was stimulated at all beta-D-xyloside concentrations, reflecting synthesis of xyloside initiated dermatan-35SO4 chains. In contrast to dramatic effects on chondroitin-SO4 synthesis and ureteric branching, beta-D-xyloside had no effect on heparan-SO4 synthesis or on development of the glomerulus and glomerular basement membrane. We thus characterize the proteoglycans synthesized early in the course of renal organogenesis and describe observations which suggest an association between metabolism of chondroitin-SO4 proteoglycan and development of the ureter.     

Phosphatidylinositol Phosphodiesterase (Phospholipase C) Activity in the Pineal Gland: Characterization and Photoneural Regulation

Phosphatidylinositol phosphodiesterase (PL-C) appears to be a key element in the adrenergic regulation of pineal cyclic AMP levels. In the present study, the rat pineal enzyme was characterized using exogenous [3H]phosphatidylinositol (0.5 mM) as substrate. Half the enzyme activity was found in the cytosolic fraction, but the highest specific concentration was associated with the membrane fraction. Two pH optima (5.5 and 7.5) of enzyme activity were observed for the membrane fraction but only one in the cytosol fraction (pH 5.5). Enzyme activity in both fractions was Ca2+ dependent. In the case of the membrane protein in pH 7.5, the enzyme activity was sensitive to changes in Ca2+ in the 10-100 nM range. Addition of an equimolar concentration of phosphatidylinositol 4-phosphate nearly completely inhibited the hydrolysis of [3H]phosphatidylinositol; other phospholipids (1.0 mM) were less potent. This may reflect our present finding that [3H]phosphatidylinositol 4-phosphate is a better substrate than [3H]phosphatidylinositol for the enzyme. Stimulus deprivation (2 weeks of constant light or superior cervical ganglionectomy) reduced the cytosolic activity by 30% and had no effect on the membrane-associated enzyme.     

Structural relatedness of lysis proteins from colicinogenic plasmids and icosahedral coliphages

The host-lysis-inducing functions of phi X174 protein E and MS2 protein L were recently shown to reside on the N-terminal and C-terminal halves of the two respective lysis proteins. In the present study it is shown that the small lysis proteins encoded in various colicinogenic plasmids share local sequence similarities and certain structural characteristics with the essential peptides of their coliphage-coded counterparts. Despite their dissimilar sizes and origins, it is suggested that the colicinogenic lysis proteins are functionally analogous and evolutionarily related to those of icosahedral single- stranded DNA and RNA phages.      

Ecology of muskoxen in Jameson Land, northeast Greenland

Muskoxen Ovibos moschatus in Jameson Land exist at a density of somewhat more than 1 km⁻² of useable habitat and select moist meadows and snow bed vegetation for summer grazing and wind-exposed, dry dwarf shrub heath vegetation in winter. Graminoids dominate the winter diet and willows are the main component of the summer diet. Quality of the winter diet, as measured by the protein to fiber ratio is about one fourth that of the summer diet. During summer muskoxen supplement dietary sodium by using mineral licks. Muskoxen, especially females, retain considerable unused fat reserves through the winter and these are drawn upon during the post-calving period of lactation. Alternate year breeding is a common occurrence. Calves are frequently not weaned before the end of their first winter. Mean calf mortality is relatively low in the absence of significant predation and annual removal by hunting Inuits approaches the annual increment.     

23Na NMR study of intracellular sodium ions in Dictyostelium discoideum amoeba

The intracellular sodium concentration in the amoebae from the slime mold Dictyostelium discoideum has been studied using 23Na NMR. The 23Na resonances from intracellular and extracellular compartments could be observed separately in the presence of the anionic shift reagent Dy(PPPi)7-2 which does not enter into the amoebae and thus selectively affects Na+ in the extracellular space. 31P NMR was used to control the absence of cellular toxicity of the shift reagent. The intracellular Na+ content was calculated by comparison of the intensities of the two distinct peaks arising from the intra- and extracellular spaces. It remained low (0.6 to 3 mM) in the presence of external Na+ (20 to 70 mM), and a large Na+ gradient (20- to 40-fold) was maintained. A rapid reloading of cells previously depleted of Na+ was readily measured by 23Na NMR. Nystatin, an antibiotic known to perturb the ion permeability of membranes, increased the intracellular Na+ concentration. The time dependence of the 23Na and 31P NMR spectra showed a rapid degradation of Dy(PPPi)7-2 which may be catalyzed by an acid phosphatase.