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.     

Influence of acetylcysteine on cytogenetic effects of etoposide in mouse oocytes

The influence of N-acetylcysteine (ACC) on the cytogenetic effects of etoposide in F₁ CBA × C57BL/6 mice was studied. Etoposide introduced intraperitoneally in doses of 10, 20, 40, and 60 mg/kg has a dose-dependent clastogenic activity and has an aneugenic effect with the induction of mainly hypohaploid oocytes. ACC significantly decreases the aneugenic and clastogenic activity of etoposide (20 mg/kg) in oocytes of 6-, 9-, and 12-week-old mice during triple introduction at a dose 200 mg/kg per os. The most pronounced anticlastogenic ACC activity (an 80% decrease) was registered in 9-week-old females; a 100% decrease in aneugenesis was detected in 6-week-old female mice.     

Phosphorylation of the kinase suppressor of ras by associated kinases

The kinase suppressor of Ras (KSR) is a loss-of-function allele that suppresses the rough eye phenotype of activated Ras in Drosophila and the multivulval phenotype of activated Ras in Caenorhabditis elegans. The physiological role of mammalian KSR is not known. We examined the mechanisms regulating the phosphorylation of this putative kinase in mammalian cells. Wild-type mouse KSR and a mutated KSR protein predicted to create a kinase-dead protein are phosphorylated identically in intact cells and in the immune complex. Phosphopeptide sequencing identified 10 in vivo phosphorylation sites in KSR, all of which reside in the 539 noncatalytic amino terminal amino acids. Expression of the amino terminal portion of KSR alone demonstrated that it was phosphorylated in the intact cell and in an immune complex in a manner indistinguishable from that of intact KSR. These data demonstrate that the kinase domain of KSR is irrelevant to its phosphorylation state and suggest that the phosphorylation of KSR and its association with a distinct set of kinases may affect intracellular signaling.     

Morphology and untrastructure of the antennal sense organs in tenebrionid larvae <Emphasis Type="Italic">Tenebrio molitor</Emphasis> L. and <Emphasis Type="Italic">Zophobas rugipes</Emphasis> Kirsch (Coleoptera: Tenebrionidae)

The distribution, external morphology, and ultrastructure of various types of sensilla in the antennae of tenebrionid larvae Tenebrio molitor and Zophobas rugipes are studied by means of scanning and transmission electron microscopy. On the antennae of T. molitor there are sensilla of four basic morphological types: basiconic, styloconic, trichoid, and papillate sensilla. On the antennae of Z. rugipes, in addition to the aforementioned ones, there are placoid sensilla. Ultrastructure points to olfactory function of basiconic and placoid sensilla. Other sensillum types are contact chemoreceptors.     

Sensory organs of the antennae and mouthparts of beetle larvae (Coleoptera)

The sensilla located on the antennae and maxillary and labial palps of the larvae of 64 beetle species from 22 families were studied using electron microscopy. The larvae of beetles living in different habitats and having different trophic specializations possess a uniform structure of the sensory organs. They are composed of two groups of sensilla on the apical and subapical segments of the antennae, one apical group of sensilla on both maxillary and labial palps, and one or several digitiform sensilla on the lateral surface of the maxillary and, occasionally, labial palp. The external morphology of the sensory organs is adaptive and represents modifications of the initial type. Band-shaped sensilla or placoid sensilla, clearly different from the initial sensory organs, appear in some taxa as rare exceptions, while other groups display either partial reduction of the receptor organs (Gyrinidae) or reduction of the cuticular parts of the sensilla (Cantharidae).     

Extracellular yeast-lytic enzyme of the bacterium <Emphasis Type="Italic">Lysobacter</Emphasis> sp. XL 1

An enzyme exhibiting yeast-lytic activity has been isolated from the culture liquid of the bacterium Lysobacter sp. XL 1. The optimal conditions for the hydrolysis of Saccharomyces cerevisiae cells by the enzyme have been established: 0.15 M sodium acetate buffer, pH 6.0, 50 degrees C. The yeast-lytic activity of the enzyme is inhibited by EDTA, p-chloromercuribenzoate, and phenylmethylsulfonyl fluoride. According to the data of SDS-PAGE, the molecular weight of the protein is 36 kD. The enzyme hydrolyzes casein, hemoglobin, and synthetic peptide Abz-Ala-Ala-Phe-pNA, i.e. it exhibits proteolytic activity. The properties of the enzyme and its molecular weight correspond to those of a previously isolated extracellular metalloproteinase. The N-terminal amino acid sequence of the protein exhibits 67% homology with the N-terminal sequence of achromolysine of Achromobacter lyticus (EC 3.4.24.-).     

Rac-dependent anti-apoptotic signaling by the insulin receptor cytoplasmic domain.

Mutations in the cytoplasmic domain of the insulin receptor that block the ability of the receptor to stimulate glucose uptake do not block the receptor's ability to inhibit apoptosis (Boehm, J. E., Chaika, O. V., and Lewis, R. E. (1998) J. Biol. Chem. 273, 7169-7176). To characterize this survival pathway we used a chimeric receptor (CSF1R/IR) consisting of the ligand-binding domain of the colony-stimulating factor-1 receptor spliced to the cytoplasmic domain of the insulin receptor and a mutated version of the chimeric receptor containing a 12-amino acid deletion of the juxtamembrane domain (CSF1R/IRDelta960). In addition to the inhibition of apoptosis, activation of either the CSF1R/IR or the CSF1R/IRDelta960 rapidly induced membrane ruffling in Rat1 fibroblasts. The small GTPase Rac mediates membrane ruffling. Activated and dominant-inhibitory mutants of Rac and other small GTPases were expressed in Rat1 fibroblasts to examine a potential link between the intracellular pathways that induce membrane ruffling and promote cell survival. The anti-apoptotic action of the CSF1R/IRDelta960 was reversed by dominant-inhibitory Rac(N17), but not by Ras(N17) or Cdc42(N17). Activated Rac(V12), but not Ras(D12) or Cdc42(V12), promoted cell survival in the absence of insulin. These data implicate Rac as a mediator of an unique anti-apoptotic signaling pathway activated by the insulin receptor cytoplasmic domain.     

Scaling of the Sense Organs of Insects. 2. Sensilla. Discussion. Conclusion

Entomological Review - The second part of our review systematizes the published evidence of scaling of the insect antennal sensory system and provides an allometric analysis of quantitative data...