Mesodern-inducing factors and mesodermal patterning

Identification of the signalling molecules involved in mesoderm formation in amphibian embryos still presents problems. None of the original candidates, such as activin, have been definitively ruled out, and the new factors, such as the nodal-related genes, have come on to the scene. Of the original candidates, activin has been definitively shown to act as a morphogen, whereas bone morphogenetic protein (BMP)-4 has emerged as a ventral inducer and an inhibitor of neural differentiation. The effects of BMP-4 are antagonized by chordin, a molecule related to the product of the Drosophila gene short gastrulation.     

Repression of endo-1,4-beta-glucanase formation in Penicillium janthinellum and product inhibition of its 1,4-beta-glucanases and cellobiases

Endo-1,4-beta-glucanase formation of Penicillium janthinellum was repressed by glucose, sophorose, and glycerol. Chromatography on DEAE-Sephadex A-50 was employed to separate the 1,4-beta-glucanases from two cellobiases. The 1,4-beta-glucanases were inhibited competitively by cellobiose and glucose, and the two cellobiases were inhibited by glucose and glucono-delta-lactone.     

Role of virus variants and cells in maintenance of persistent infection by measles virus.

Hamster embryo fibroblasts persistently infected with a derivative of the Schwarz vaccine strain of measles virus spontaneously released virus particles with an average buoyant density considerably lower than that of the parental virus. The released virus contained all of the measles virus structural proteins and interfered with replication of standard virus. All of the virus structural proteins were associated with a membrane-free cytoplasmic extract from the persistently infected cells. Membrane-free cytoplasmic extracts prepared from Vero cells lytically infected with Schwarz strain measles contained little or no virus envelope structural protein. Maintenance of persistent infection may involve both the presence of virus variants and a defect in the ability of the infected cell to replicate the virus efficiently.     

Efficacy of mycobacterial components in the immunotherapy of mice with pulmonary tumor deposits

Summary The effectiveness of each of two mycobacterial components and a synthetic analog of one of them in the eradication of pulmonary deposits of intravenously injected syngeneic fibrosarcoma 1023 in C3H mice was studied. BCG cell walls (BCG CW), trehalose 6,6-dimycolate (TDM) or 6,6-di-0-2-tetradecyl, 3-hydroxyoctadecanoyl-,-trehalose (C76), a synthetic analog of TDM, was administered in emulsified form by three different routes: intraperitoneal, intradermal, or intravenous, 24 h after intravenous injection of 1023 tumor cells. The most effective form of therapy was TDM given by the intraperitoneal route; about 50% of treated animals were cured. Higher doses of BCG CW or C76 also led to a significant number of cures. Each agent caused a significant prolongation of survival time of the treated mice at two or more of the dosages tested; however, their routes of optimal activity varied.     

Immunotherapy of a guinea pig hepatoma with ultrasonically prepared mycobacterial vaccines

Summary Oil-in-water emulsions containing either mycobacterial cell walls (CW) or killed whole cells attached to the oil droplets were prepared by ultrasonication and by a modified grinding procedure. The immunotherapeutic potency of the ultrasonically prepared vaccines was at least as great as that of similar vaccines prepared by emulsification in a tissue grinder. Among the advantages of ultrasonication over grinding for the preparation of mycobacterial cell and cell wall vaccines are simplicity and the ease with which sterility may be maintained. Both the ultrasonic and modified grinding methods are less time-consuming than published procedures for preparing mycobacterial vaccines.