A new role for PGRP-S (Tag7) in immune defense: lymphocyte migration is induced by a chemoattractant complex of Tag7 with Mts1

PGRP-S (Tag7) is an innate immunity protein involved in the antimicrobial defense systems, both in insects and in mammals. We have previously shown that Tag7 specifically interacts with several proteins, including Hsp70 and the calcium binding protein S100A4 (Mts1), providing a number of novel cellular functions. Here we show that Tag7–Mts1 complex causes chemotactic migration of lymphocytes, with NK cells being a preferred target. Cells of either innate immunity (neutrophils and monocytes) or acquired immunity (CD4⁺ and CD8⁺ lymphocytes) can produce this complex, which confirms the close connection between components of the 2 branches of immune response.     

Inhibitory Effect of Autoclaving Whey-Based Medium on Propionic Acid Production by Propionibacterium shermanii

Propionic acid production by Propionibacterium shermanii was compared in pasteurized and autoclaved whey-based media. Propionic acid production decreased with increasing whey concentration in autoclaved media but not in pasteurized media. Increasing the yeast extract concentration from 5 to 10 g/liter greatly reduced the inhibitory effect of autoclaving.     

Production of High-Viscosity Whey-Glucose Broths by a Xanthomonas campestris Strain

Acclimation of a sandy soil to an air-natural gas mixture stimulated the biological oxidation of chloroform to carbon dioxide. Acetylene and methane inhibited chloroform oxidation. Chloroform oxidation continued up to 31 days in the absence of methane. Chloroform oxidation rates increased at chloroform concentrations up to 5 μg g of soil^-1.     

Production of Viscous Dextran-Containing Whey-Sucrose Broths by Leuconostoc mesenteroides ATCC 14935

Viscous broths were produced by growing Leuconostoc mesenteroides on a medium containing whey supplemented with sucrose. When combined with similarly produced xanthan-containing broths, a synergistic increase in viscosity was observed.     

Plasminogen activator and collagenase production by cultured capillary endothelial cells

Cultured bovine capillary endothelial (BCE) cells produce low levels of collagenolytic activity and significant amounts of the serine protease plasminogen activator (PA). When grown in the presence of nanomolar quantities of the tumor promoter 12-O-tetradecanoyl phorbol-13-acetate (TPA), BCE cells produced 5-15 times more collagenolytic activity and 2-10 times more PA than untreated cells. The enhanced production of these enzymes was dependent on the dose of TPA used, with maximal response at 10(-7) to 10(-8) M. Phorbol didecanoate (PDD), an analog of TPA which is an active tumor promoter, also increased protease production. 4-O-methyl-TPA and 4α-PDD, two analogs of TPA which are inactive as tumor promoters, had no effect on protease production. Increased PA and collagenase activities were detected within 7.5 and 19 h, respectively, after the addition of TPA. The TPA-stimulated BCE cells synthesized a urokinase-type PA and a typical vertebrate collagenase. BCE cells were compared with bovine aortic endothelial (BAE) cells and bovine embryonic skin (BES) fibroblasts with respect to their production of protease in response to TPA. Under normal growth conditions, low levels of collagenolyic activity were detected in the culture fluids from BCE, BAE, and BES cells. BCE cells produced 5-13 times the basal levels of collagenolytic activity in response to TPA, whereas BAE cells and BES fibroblasts showed a minimal response to TPA. Both BCE and BAE cells exhibited relatively high basal levels of PA, the production of which was stimulated approximately threefold by the addition of TPA. The observation that BCE cells and not BAE cells produced high levels of both PA and collagenase activities in response to TPA demonstrates a significant difference between these two types of endothelial cells and suggests that the enhanced detectable activities are a property unique to bovine capillary and microvessel and endothelial cells.     

Separation of dissociated thyroid follicular and parfollicular cells: association of serotonin binding protein with parafollicular cells

Parafollicular cells (PC) of the sheep thyroid gland are neural crest derivatives that synthesize and release the biogenic amine serotonin (5-HT) as well as the hormone calcitonin. The thyroid also contains a highly specific serotonin-binding protein (SBP). Separation of dissociated thyroid cells was done to study the cellular localization of SBP and to develop a means of isolating PC for study. Various methods were used to obtain an enriched and purified population of PC. Minced thyroid glands were enzymatically dissociated and the cells were layered on a Ficoll linear density gradient. Fractions obtained from the gradient were examined for cell number, viability, 5-HT concentration, SBP activity, and morphology by electron microscopy. One of the fractions was found to be enriched in PC. High levels of 5-HT and SBP were also found in this fraction, whereas these levels were low where the majority of cells were found. This PC-rich fraction, however, contained numerous follicular cells (FC); therefore, additional approaches to cell separation were used. FC can be stimulated in vitro with thyroid stimulating hormone (TSH) to become intensely phagocytic. When stimulated cells were incubated in the presence of silica microspheres, the FC engulfed the microspheres, which were toxic to them. PC did not become phagocytic and were unharmed by the microspheres. Suspended cells, after incubation with microspheres, were centrifuged on a discontinuous gradient, and a PC-rich fraction was obtained. Silica, however, interfered with analysis of SBP. Another method to take advantage of the phagocytic potential of FC was therefore used. TSH-stimulated cell suspensions were passed through a column of sepharose to which thyroglobulin had been coupled. Stimulated FC apparently adhered to the beads and were retained by the columns. Fractions eluting from the columns were greatly enriched with PC. These fractions contained high levels of 5-HT and SBP, and considerably reduced FC contamination was found by quantitative electron microscopy. It is concluded that SBP is localized to PC in the sheep thyroid. The idea that these cells resemble serotonergic neurons in their mechanisms of 5-HT storage is supported.     

Palatability and feeding preferences of Uresiphita maorialis (Lepidoptera: Crambidae) for three Sophora species

In a three-hour bioassay, we tested the palatability and feeding preferences of Uresiphita maorialis (kōwhai moth) for Sophora tetraptera, Sophora microphylla and Sophora prostrata. Palatability tests showed no differences among the Sophora species. Feeding preferences, on the other hand, showed that S. tetraptera and S. microphylla leaves are preferred over S. prostrata leaves. Our results support our field observations in Wellington city parks and gardens showing that S. tetraptera and S. microphylla plants frequently have higher densities of larvae than S. prostrata.     

Changes in membrane cholesterol affect caveolin-1 localization and ICC-pacing in mouse jejunum

Pacing of mouse is dependent on the spontaneous activity of interstitial cells of Cajal in the myenteric plexus (ICC-MP). These ICC, as well as intestinal smooth muscle, contain small membrane invaginations called caveolae. Caveolae are signaling centers formed by insertions of caveolin proteins in the inner aspect of the plasma membrane. Caveolins bind signaling proteins and thereby negatively modulate their signaling. We disrupted caveolae by treating intestinal segments with methyl beta-clodextrin (CD) to remove cholesterol or with water-soluble cholesterol (WSC) to load cholesterol. Both of these treatments reduced pacing frequencies, and these effects were reversed by the other agent. These treatments also inhibited paced contractions, but complete reversal was not observed. To evaluate the specificity of the effects of CD and WSC, additional studies were made of their effects on responses to carbamoyl choline and to stimulation of cholinergic nerves. Neither of these treatments affected these sets of responses compared with their respective time controls. Immunochemical and ultrastructural studies showed that caveolin 1 was present in smooth muscle membranes and ICC-MP. CD depleted both caveolin 1 and caveolae, whereas WSC increased the amount of caveolin 1 immunoreactivity and altered its distribution but failed to increase the number of caveolae. The effects of each agent were reversed in major part by the other. We conclude that signaling through caveolae may play a role in pacing by ICC but does not affect responses to acetylcholine from nerves or when added exogenously.     

Successful immunotherapy with matrix metalloproteinase-derived peptides in adjuvant arthritis depends on the timing of peptide administration

We have recently found that matrix metalloproteinases (MMPs) are targets for T-cell and B-cell reactivity in experimental arthritis. In the present article, we investigate whether modulation of MMP-specific T-cell responses could influence the course of adjuvant arthritis (AA). Lewis rats were treated nasally with MMP peptides prior to or after AA induction. Administration of the MMP-10 or the MMP-16 peptide prior to AA induction reduced the arthritic symptoms. In contrast, administration of the MMP-10 peptide after AA induction aggravated the arthritic symptoms. The present study shows the possible usefulness of MMP peptides for immunotherapy. However, a clear understanding of proper timing of peptide administration is crucial for the development of such therapies.     

Effects of medium viscosity on kinetics of the enzymatic reaction catalyzed by bacterial RNase

Effects of medium viscosity on kinetic parameters of poly(U) hydrolysis catalyzed by RNase from Bac. intermedius 7P (binase) were studied in solutions of sucrose (4-50 wt. %) and glycerol (35-62 wt. %) in Tris--sodium acetate buffer (pH 7.5) at 25 degreesC. The rate constant of reaction kcat was practically unchanged over a wide range of viscosities (1-15 cP for sucrose and 2.5-3 cP for glycerol). In glycerol solutions, kcat slightly increased with viscosity increase from 4 to 10 cP. Addition of NaCl to the buffer medium resulted in an inhibitory effect of Na+ on kcat, prevented by 50% sucrose or 60% glycerol. It is concluded that binase-catalyzed poly(U) cleavage occurs through a "tense"-substrate mechanism, similarly to reactions catalyzed by alpha-chymotrypsin, trypsin, and laccase.