Effect of Lytic Enzymes of Acanthamoeba castellanii on Bacterial Cell Walls

Extracts of Acanthamoeba castellanii (Neff) contain alpha- and beta-glucosidase, beta-galactosidase, beta-N-acetylglucosaminidase, amylase, and peptidase. All of these activities are optimal between pH 3 and 4. These extracts also were found to clarify suspensions of cell walls from nine different gram-positive bacteria, including Micrococcus lysodeikticus. The pH optimum for the lytic activity was between 3 and 4. The extent of lysis of the various cell walls did not correlate with the release of free amino groups and of free N-acetylated sugars from the walls during digestion with these extracts. Suspensions of cell walls of Escherichia coli (a gram-negative bacterium), Cordiceps militaris (a fungus), and Acanthamoeba cysts, as well as of colloidal chitin, were not clarified by incubation with these extracts, although reducing sugars were released from each of these materials. Exhaustive digestion of M. lysodeikticus walls by lysozyme released no free N-acetylglucosamine. The products of exhaustive digestion of this cell wall with Acanthamoeba extracts were free N-acetylglucosamine, free N-acetylmuramic acid, glycine, alanine, glutamic acid, lysine, and N-acetylmuramic acid peptide fragments. These results suggest that the amoeba extracts contain endo- and exo-hexosaminidases, in addition to beta-hexosaminidase and peptide hydrolases.     

NON-INFECTIOUS INFLAMMATORY AND NEOPLASTIC DISORDERS OF THE MALE GENITALIA

The cutaneous manifestations of the male external genitalia are difficult to diagnose. They may be associated with systemic disease (Reiter''s disease, psoriatic arthritis, angiokeratoma corporis diffusum). In dealing with a lesion of this area that does not heal, adequate biopsy is advisable to rule out malignant disease (Bowen''s disease, melanoma, Kaposi''s sarcoma, Paget''s disease, erythroplasia).     

Ketamine-induced tongue protrusions in rats

1. The purpose of this study was to demonstrate that ketamine anesthesia (100 mg/kg) induces tongue protrusions (P) in addition to retrusions (R) and swallows (S) in adult rats. 2. These linguo-pharyngeal events occur alone or combined in various sequential patterns. 3. The SPR sequence is not the predominant pattern in all preparations suggesting profound disruption of physiological linkages by ketamine. 4. Haloperidol administration suppresses these events for 1-120 min depending on the dose (0.75-2.5 mg/kg). 5. Swallows are the least vulnerable to haloperidol. 6. This and previous findings provide further evidence that ketamine induced linguo-pharyngeal activity can serve as a model for acute or tardive dyskinesia better than stereotypies.     

Effects of medium composition on penicillin-induced hydrolysis and loss of RNA and culture turbidity in group A streptococci.

Exposure to penicillin G of exponentially growing cultures of group A streptococci growing in chemically defined medium (CDM) can lead to extensive loss of culture turbidity. Significant reductions in culture turbidity did not accompany comparable treatments of group A streptococci growing in Todd-Hewitt broth (THB). Studies with THB and a high-molecular-weight (greater than 12,000) fraction of THB demonstrated that components in this complex medium inhibited the efflux of RNA hydrolysis products from otherwise intact cells. Hydrolysis products accumulated intracellularly and inhibited the extensive hydrolysis of RNA and consequently the loss of culture turbidity. Results of survival studies with cultures of group A streptococci exposed to penicillin G in THB demonstrated that this treatment protocol produces conditions of phenotypic tolerance relative to exposure in CDM. In combination, these findings provide further support for the hypothesis of RNA hydrolysis as the bactericidal mechanism of penicillin G action in this nonlytic death phenotype.     

IL-1 as adjuvant. Role of T cells in the augmentation of specific antibody production by recombinant human IL-1 alpha

Human rIL-1 alpha significantly enhanced splenic plaque-forming cells (PFC) to SRBC in vitro and in vivo. A single i.p. injection was sufficient to produce a fivefold or greater increase in the generation of PFC in a primary response. IL-1 treatment resulted in an increased production of Ag-specific PFC, both in vitro and in vivo, in combination with suboptimal doses of Ag. When IL-1 was given with a primary dose of Ag in vivo, an enhanced IgG response occurred. IL-1 enhanced in vivo carrier priming for an anti-hapten PFC response, indicating increased Th activity. Furthermore, T cells from spleens of mice treated with IL-1 provided significantly more help in both carrier (SRBC)- and hapten (TNP)- specific PFC. The enhancement of PFC by IL-1 in vitro occurred even in the presence of an excess of neutralizing anti-IL-2 antibody. These results suggest that IL-1 may enhance T cell-dependent antibody production in part by increasing Th activity, and that the mechanism of IL-1 action in increasing antibody production involves pathways in addition to the induction of IL-2 secretion.     

A method for cultivating morphologically undifferentiated embryonic stem cells from porcine blastocysts

Variable conditions were tested to determine an in-vitro cultivation method for the formation of morphologically undifferentiated embryonic stem cells from the inner cell mass (ICM) derived outgrowth of porcine blastocysts. Although all 16 Day-9 embryos failed to form colonies, 14 such colonies were obtained from a total of 69 Day-10 embryos when they were co-cultivated with porcine uterine fibroblast (PUF) cells over a 6-day period. The best results were obtained in Dulbecco's modified Eagle medium (DMEM) with 10% fetal calf serum and 10% porcine serum supplemented with bovine insulin and beta-mercaptoethanol, in which six out of seven embryos formed adequate ICM-derived colonies. Since murine fibroblasts were not found to be suitable feeder cells in this procedure, an endocrine synergistic interaction, which promotes embryonic attachment and colony formation, between porcine blastocysts and PUF cells is hypothesized. Continued propagation of the ICM-derived cells was not dependent on these factors; a total of seven cell lines were obtained after three to five subsequent passages on murine feeder-layers that resembled morphologically undifferentiated embryonic cells.