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.     

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.     

Interhemispheric asymmetry of the spatial organization of human cortical potentials during the perception of emotional and indifferent images

In 13 healthy subjects dynamic characteristics of potentials spatial-temporal organization (PSTO) in the cortical left and right hemispheres at presentation of emotionally coloured and indifferent graphic images were studied by the method of quantitative evaluation of subsequent electroencephalotopograms. It is shown that, in contrast to the state of calm alertness, presentation of emotional and indifferent images leads to a decrease of the time of discordance in the hemispheres activity i.e. to synchronization increase. At the action of emotionally coloured images differences were found between the reorganizations of the left and right hemispheres, while there were no such differences at the presentation of indifferent images.     

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.     

Expression of mammalian geranylgeranyltransferase type-II in Escherichia coli and its application for in vitro prenylation of Rab proteins

Mammalian geranylgeranyltransferase type II (GGTase-II) is a 100-kDa heterodimer that catalyzes the transfer of two 20-carbon geranylgeranyl groups from geranylgeranyl pyrophosphate onto C-terminal cysteine residues of Rab GTPases. This modification is essential for the biological activity of Rab proteins. Geranylgeranylation can be performed in vitro using recombinant GGTase-II but so far large-scale production of the enzyme was challenging. We report here the design of a two plasmid expression system that will produce GGTase-II at levels as high as 15 mg/L in Escherichia coli. The protein was produced as a heterodimer with the alpha subunit bearing a cleavable tandem 6His-glutathione S-transferase (GST) tag that was used for two-step purification of the enzyme. Purified enzyme was functionally active as determined by in vitro prenylation and phosphoisoprenoid binding assay. Furthermore, the GST-tagged GGTase-II was used for preparative in vitro prenylation of the Rab7:REP-1 complex. Using this procedure, 10 mg of doubly prenylated Rab7:REP-1 complex were obtained.     

Role of working memory in forming the cognitive visual set

It was found in healthy adult subjects (n = 90) that under conditions of complication of cognitive tasks (increasing number of relevant stimuli), the stability (rigidity) of the unconscious cognitive sets markedly rises. These changes in both verbal and nonverbal sets depend on the working memory loading. The revealed dependence of the motor reaction time to the probe stimulus on the sequence of the set stimuli in a context and on the set stage suggests that unconscious cognitive sets can regulate selective attention.     

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.