The heparin binding domain of S-protein/vitronectin binds to complement components C7, C8, and C9 and perforin from cytolytic T-cells and inhibits their lytic activities

S-Protein/vitronectin is a serum glycoprotein that inhibits the lytic activity of the membrane attack complex of complement, i.e., of the complex including the proteins C5b, C6, C7, C8, and C9n. We show that intact S-protein/vitronectin or its cyanogen bromide generated fragments also inhibit the hemolysis mediated by perforin from cytotoxic T-cells at 45 and 11 microM, respectively. The glycosaminoglycan binding site of S-protein/vitronectin is responsible for the inhibition, since a synthetic peptide corresponding to a part of this highly basic domain (amino acid residues 348-360) inhibits complement- as well as perforin-mediated cytolysis. In the case of C9, the synthetic peptide binds to the acidic residues occurring in its N-terminal cysteine-rich domain (residues 101-111). Antibodies raised against this particular segment react 25-fold better with the polymerized form of C9 as compared with its monomeric form, indicating that this site becomes exposed only upon the hydrophilic-amphiphilic transition of C9. Since the cysteine-rich domain of C9 has been shown to be highly conserved in C6, C7, and C8 as well as in perforin, the inhibition of the lytic activities of these molecules by S-protein/vitronectin or by peptides corresponding to its heparin binding site may be explained by a similar mechanism.     

Midsummer heat wave effects on lacustrine plankton: Variation of assemblage structure and fatty acid composition

The effects of the 2003 European heat wave on a freshwater plankton assemblage and its fatty acid (FA) composition were investigated. Composition and FA profiles of four size categories of planktonic organisms collected in 2003 were compared to those of the colder year 2002.     

Developmental study of afferented and deafferented bee antennal lobes.

The role of antennal sensory projections on the ontogeny of the bee antennal lobe was analyzed using both light and transmission electron microscopy. Normal and deafferented developing antennal lobes were examined. The results obtained show that (1) initiation of synaptogenesis in the antennal lobe is independent of the arrival of sensory inputs; (2) sensory inputs are necessary for setting up the glomerular antennal lobe organization; (3) regressive events, such as the reduction of synapse density, occur during the development of the antennal lobe; and (4) glomeruli formation appears as related to glia development.     

Size distribution of luteal cells from pregnant and non-pregnant marmoset monkeys and a comparison of the morphology of marmoset luteal cells with those from the human corpus luteum

The size distribution of marmoset luteal cells was determined on Days 6, 14 and 20 after ovulation in non-pregnant cycles and in early pregnancy. Image analysis was used to estimate the cell diameter of dispersed cells prepared from the marmoset corpus luteum (CL). Steroidogenic cells showed a size distribution consistent with one population of cells. There was a significant increase in mean cell diameter (P less than 0.05) from Day 6 to Day 14 in pregnant and non-pregnant animals with no further increase on Day 20. Micrographs of marmoset luteal tissue showed cells of greater than 10 micron containing the organelles typical of steroid-producing cells, and smaller non-steroidogenic cells surrounding the steroid-producing cells. On the basis of microscopy, there were no areas within the CL where cell composition was noticeably different. In contrast, micrographs of human luteal tissue showed two types of steroidogenic cell; most cells were similar to those in the marmoset CL but a smaller population of smaller cells could be distinguished around the periphery and along vascular septa. It is likely that these smaller and larger types of steroidogenic cells are of theca and granulosa cell origin respectively, the two cell populations differing in the degree of electron density and amount of rough endoplasmic reticulum. A distinguishing feature between marmoset and human luteal cells was the shape of the mitochondrian which were considerably rounder in marmoset luteal cells. The origin of steroidogenic cells in the marmoset CL is unclear, although in marmosets and man the luteal cell types display morphological characteristics distinct from the large and small luteal cells described for CL of the domestic ungulates.     

Perforin is present only in normal activated Lyt2+ T lymphocytes and not in L3T4+ cells, but the serine protease granzyme A is made by both subsets.

We show that among the subsets of peripheral T lymphocytes (Lyt2+ L3T4- and L3T4+ Lyt2- cells) activated in short-term cultures by stimulation with H-2 incompatible leukocytes 97% of the cytolytic activity and all detectable perforin activity resides in the Lyt2+ cells. But both populations contain approximately equal amounts of a serine protease, granzyme A, the expression of which was previously thought to be restricted to cytolytic T lymphocytes.     

Selection of somatic hybrids between diploid clones of potato (Solanum tuberosum L.) transformed by direct gene transfer

Summary Five diploid potato clones have been transformed by electroporation of protoplasts with different selectable markers. The resulting diploid regenerated plants have been used in somatic hybridization. It has been shown that hybrid cell selection on the basis of antibiotic or herbicide resistances brought by the two parents of fusion is an efficient method for the recovery of tetraploid somatic hybrids.     

Effects of prostaglandin F2 alpha prostaglandin E2 and arachidonic acid on the induction of oviposition in vivo and in vitro in oviparous lizards.

Gravid females of four different species of oviparous lizard were treated in vivo with varying doses of prostaglandin F2 alpha (PGF2 alpha), prostaglandin E2 or arachidonic acid (AA). In contrast to previous studies examining birds and viviparous lizards, no dosage induced oviposition in any of the treated females. All females, however, did exhibit behaviors associated with oviposition. Intact oviducts removed from gravid females and placed in organ culture did oviposit when treated with 30 or 100 ng PGF2 alpha/ml of culture media. Arachidonic acid at similar concentrations also was effective in stimulating birth. These data suggest that prostaglandins can stimulate oviposition in oviparous lizards but further suggest that their action may be inhibited by oviducal innervation until just prior to natural birth.     

Preliminary molecular studies on two chromosome 2 encoded genes, c-abl and beta 2M, in radiation-induced murine myeloid leukaemias

The majority of radiation-induced murine myeloid leukaemias are characterized by deletion and/or translocation of an interstitial region of chromosome 2, and there is evidence that such events may occur very early in myeloid leukaemogenesis. Analyses presented and discussed here on the structure and function of two possibly relevant chromosome 2 encoded genes (c-abl and beta 2M) lead to the preliminary conclusion that neither are directly involved nor activationally changed by the characteristic chromosome 2 rearrangements.     

Comparative study of the pulmonary effects of intravenous leukotrienes and other bronchoconstrictors in anaesthetized guinea pig

Pulmonary responses to intravenous leukotrienes C₄, D₄ and E₄ administered as a bolus injection and by continuous infusion were studied in anesthetized guinea pigs. LTD₄, LTC₄ and LTE₄ (respective ED₅₀ of 0.21 ± .1, 0.64 ± .2 and 2.0 ± .1 μg kg⁻¹) produced dose-dependent increases in insufflation pressure when given as a bolus injection to anesthetized guinea pigs (Konzett-Rössler). Bronchoconstriction was antagonized by FPL-55712 (50–200 μg kg⁻¹), and indomethacin (50–200 μg kg⁻¹) but was not significantly altered by mepyramine (1.0 mg kg⁻¹), methysergide (0.1 mg kg⁻¹), intal (10 mg kg⁻¹) mepacrine (5 mg kg⁻¹) or dexamethasone (10 mg kg⁻¹). The beta adrenoceptor blocker, timolol (5 μg kg⁻¹) produced a significantly greater potentiation of the responses to the leukotrienes than to arachidonic acid, histamine and acetylcholine. Responses to bolus injection of LTE₄ but not LTD₄ or LTC₄ were partially antagonized by atropine (100 μg kg⁻¹) and bilateral vagotomy. In experiments of a different design, continuous infusion of LTD₄ and LTE₄ (2.8–3.2 μg kg⁻¹ min⁻¹) into indomethacin-treated animals produced slowly developing increases in pulmonary resistance and decreases in compliance. The increase in resistance produced by LTE₄ and LTD₄ was partly reversed by intravenous FPL-55712 (1.0 mg kg⁻¹) and atropine (100 μg kg⁻¹) but was almost completely reversed by FPL-55712 (3 – 10 mg kg⁻¹). These findings indicate that leukotrienes can produce bronchoconstriction in guinea pigs through cyclooxygenase-dependent and cyclooxygenase independent mechanisms both of which are blocked by FPL-55712. Cholinergic mechanisms are involved in the mediation of part of the response to bolus injection of LTE₄ as well as a small part of the initial response to continuous infusion of LTD₄ and LTE₄. Intrinsic beta adrenoceptor activation serves to down modulate responses to the leukotrienes to a greater extent than responses to arachidonic acid, histamine and acetylcholine.     

Alterations in the Fatty Acid Composition of Rat Brain Cells (Neurons, Astrocytes, and Oligodendrocytes) and of Subcellular Fractions (Myelin and Synaptosomes) Induced by a Diet Devoid of n-3 Fatty Acids

Abstract: Rats were fed through four generations with a semisynthetic diet containing 1.0% sunflower oil (6.7 mg/ g n-6 fatty acids, 0.04 mg/g n-3 fatty acids). Ten days before mating, half of the animals received a diet in which sunflower was replaced by soya oil (6.6 mg/g n-6 fatty acids, 0.8 mg/g n-3 fatty acids) and analyses were performed on their pups. Fatty acid analysis in isolated cellular and subcellular material from sunflower-fed animals showed that the total amount of unsaturated fatty acids was not reduced in any cellular or subcellular fraction (except in 60-day-old rat neurons). All material from animals fed with sunflower oil showed an important reduction in the docosahexaenoic acid content, compensated (except in 60-day-old rat neurons) by an increase in the n-6 fatty acids (mainly C22:5 n-6). When comparing 60-day-old animals fed with soya oil or sunflower oil, the n-3/n-6 fatty acid ratio was reduced 16-fold in oligodendrocytes, 12-fold in myelin, twofold in neurons, sixfold in synaptosomes, and threefold in astrocytes. No trienes were detected. Saturated and monounsaturated fatty acids were hardly affected. This study provides data on the fatty acid composition of isolated brain cells.