Ecto-nucleotide triphosphatase activity of human lymphocytes: studies of normal and CLL lymphocytes

We have studied the apparent kinetic parameters of the ecto-nucleotide triphosphatase from CLL B lymphocytes and compared them to blood and tonsillar B and T cells. The Vmax of the ecto-ATPase activity in CLL B lymphocytes, was 65 +/- 10 fmol Pi/cell per 30 min compared to 37 +/- 2.1 in blood B lymphocytes, and 8.5 +/- 1.7 in blood T lymphocytes. The ATPase of membranes prepared from CLL, tonsillar B and T, and blood T lymphocytes had a relationship among the cell types similar to that seen in intact cells. However, no difference in the km for ATP, .17 mM, or the km for magnesium, .15 mM was found in the ecto-ATPase of CLL lymphocytes as compared to blood or tonsillar B cells. The ectoenzyme of CLL cells hydrolyzed GTP, ITP, CTP, and UTP as well as ATP. Further, ATP added to an enzyme assay containing an alternative nucleotide did not result in increased phosphate release. Nucleotide acceptance of blood B and T lymphocytes was very similar to that of CLL B cells. ATP inhibited phosphate release when present in excess of magnesium in both CLL and blood B lymphocytes. These data indicate that there is greater ectonucleotide triphosphatase activity in tonsillar and blood B lymphocytes, including CLL, as compared either to blood or tonsillar T lymphocytes. However, CLL cells showed no qualitative difference from blood or tonsillar B cells in ectonucleotidase activity. Thus, the higher activity in CLL cells is "B cell-like" and might reflect, also, their maturation stage or monoclonal origin.     

Vacuolar localization of wound-induced carboxypeptidase inhibitor in potato leaves

The wound-induced carboxypeptidase inhibitor in potato leaves was shown to be localized in the central vacuoles of the cells. The inhibitor was quantified by immunological assays (ELISA) in protoplasts and vacuoles isolated from upper unwounded leaves of 5- to 6-week old potato plants that had been wounded on their lower leaves 48 hours earlier to induce the accumulation of the carboxypeptidase inhibitor. The regulation of the synthesis and compartmentation of the inhibitor is similar to that of wound-induced serine proteinase Inhibitors I and II in potato and tomato leaves and appears to be part of an induced defense response against attacking pests.     

Lack of specificity of brain gangliosides in the modulation of lymphocyte activation

A potential role for glycolipid gangliosides to act as immunomodulating agents has been suggested. Most studies have employed brain gangliosides. We have systematically investigated highly purified murine brain gangliosides for their ability to modulate lymphocyte activation. All sialic acid classes of ganglioside inhibited lipopolysaccharide (LPS)-induced antibody secretion and all polysialated gangliosides inhibited LPS-induced DNA synthesis. Monosialated gangliosides had no effect on DNA synthesis induced by LPS. 8-BrcGMP-induced DNA synthesis was also inhibited, suggesting that a negative signal was delivered to B lymphocytes by co-cultivation with exogenous gangliosides. The lack of specificity with respect to sialic acid class observed in these studies suggests that further investigation of an immunomodulatory role for gangliosides focus on endogenous lymphocyte gangliosides.     

Study of the effect of β-1,3-glucanase fromBasidiomycete QM 806 on yeast extract production

Summary Cell free supernatants, containing -1,3-glucanase fromBasidiomycete QM 806, dramatically augmented the effect of papain on yeast autolysis. This enables the process time to be significantly reduced and/or the yield of extract to be substantially increased.     

Isolation and characterization of the proteinase inhibitor-inducing factor from tomato leaves. Identity and activity of poly- and oligogalacturonide fragments

Mild acid hydrolysis of a small (Mr = 6 kDa) pectic polysaccharide isolated from tomato leaves, an inducer of the synthesis and accumulation of two proteinase inhibitors in excised tomato plants, yielded a alpha-D-polygalacturonic acid polymer with degree of polymerization = 20 that retained proteinase inhibitor-inducing activity. Enzymic and acid hydrolysis of this polygalacturonan yielded a series of alpha-1,4-D-galacturonic acid oligomers with degrees of polymerization from 2 to 6 which were purified to homogeneity and assayed for proteinase inhibitor-inducing activity in young excised tomato plants. All of the oligomers exhibited activity. The hexagalacturonide possessed the highest activity and the trimer the lowest. The evidence supports a possible role for plant cell wall fragments as systemic messengers that regulate the expression of proteinase inhibitor genes in plant leaves in response to pest attacks.     

Recognition and response to alloantigens in vivo. I. Negative and positive selection of MLR reactivity in murine peripheral blood lymphocytes to major histocompatibility complex and Mls antigens

Specific mixed lymphocyte reaction (MLR) responsiveness to allogeneic major histocompatibility complex (MHC), or minor lymphocyte-stimulating (Mls) determinants, was depleted in the peripheral blood lymphocytes (PBL) obtained from mice 24 to 48 hr after i.v. injection of 5 to 7.5 X 10(7) MHC or Mlsa-incompatible spleen cells, respectively. Results of cell mixture experiments suggest that the generation of suppressor cells was not the explanation for this specific reduction in MLR proliferation occurring with these PBL responder cells. To gain additional insight into parameters involved in the recognition of allodeterminants in vivo, experimental manipulations of the host environment and donor cell inoculum utilized in the negative selection procedure were employed. For example, removal of the spleen in the recipient animal, an anatomic site in which injected allogeneic cells and corresponding host antigen-reactive cells (ARC) are trapped, still permitted the specific depletion in murine PBL of host ARC for donor foreign MHC antigens. This finding may implicate other sites such as the liver where unprimed host alloreactive clones are trapped. In addition, irradiation of allogeneic donor cells significantly reduced their capacity to trap alloreactive T cell clones in vivo, whereas heat treatment of the donor cells completely eliminated this ability, even though the Ia determinants were still expressed, measured by flow cytometry. After the negative selection period, kinetic analysis of proliferation showed that 3, 4, or 5 days after injection of MHC-incompatible allogeneic spleen cells, the PBL of the recipient showed specific hyperresponsiveness to the MHC-haplotype of the donor cells. Interestingly, these primed PBL responder cells had the volume distribution of small resting cells; thoracic duct lymphocytes (TDL), positively selected by adoptive transfer of T cells to irradiated semiallogeneic recipients, are reported to be mainly blast cells. In contrast to the MLR hyperresponsiveness that results from priming with MHC-incompatible splenocytes, PBL, obtained at these later time points from mice primed with Mlsa-incompatible, H-2-compatible splenocytes, showed complete unresponsiveness in MLR to these Mlsa-bearing stimulator cells, as well as some nonspecific reduction in proliferation to MHC-incompatible stimulator cells regardless of their Mls genotype.(ABSTRACT TRUNCATED AT 400 WORDS)     

Target-specific nerve regeneration through a nerve guide in the rat

Nerve regeneration across a gap in peripheral nerve has been achieved through various nonneural nerve guides in both lower and primate species. This technique can only be useful if the regenerated nerve cable grows specifically to and reinnervates the appropriate distal target. In this study, the proximal peroneal fascicle of rat sciatic nerve was inserted into the proximal limb of a Y-shaped nerve guide. Distal peroneal and tibial fascicles were placed within the two distal limbs of the same Y. The proximal peroneal nerve grew preferentially by a 2:1 ratio to the appropriate distal peroneal fascicle suggesting that target-specific reinnervation is possible through a nerve guide.     

Metabolism of the herbicide bromoxynil by Klebsiella pneumoniae subsp. ozaenae

Enrichment of soil samples for organisms able to utilize the herbicide bromoxynil (3,5-dibromo-4-hydroxybenzonitrile) as a nitrogen source yielded bacterial isolates capable of rapidly metabolizing this compound. One isolate, identified as Klebsiella pneumoniae subsp. ozaenae, could completely convert 0.05% bromoxynil to 3,5-dibromo-4-hydroxybenzoic acid and use the liberated ammonia as a sole nitrogen source. Assays of cell extracts of this organism for the ability to produce ammonia from bromoxynil revealed the presence of a nitrilase (EC 3.5.51) activity. The enzyme could not utilize 3,5-dibromo-4-hydroxybenzamide as a substrate, and no 3,5-dibromo-4-hydroxybenzamide could be detected as a product of bromoxynil transformation. Comparison of related aromatic nitriles as substrates demonstrated that the Klebsiella enzyme is highly specific for bromoxynil.