A review of the taxonomy and systematics of the pentastomid genus Raillietiella Sambon, 1910 with a description of a new species

Systematic Parasitology - Four previously established Raillietiella spp. are redescribed. Two of these, R. kochi and R. shipleyi from African monitor lizards, cannot be reliably separated, R....     

Influence of structural and physical properties of the thylakoid membrane on QA - oxidation

Using isolated pea thylakoids, the relative rate of Q_A ^- oxidation has been estimated under various conditions, from the restoration of the induction curves following a dark period and from light 1-induced changes in modulated chlorophyll fluorescence excited by light 2.Alterations of _QinfA ^sup– oxidation rates were observed under conditions which affected the degree of thylakoid stacking, the lipid fluidity and the integrity of the membranes. The results are discussed in terms of the interactions between Q_A ^- and the plastoquinone pool with particular emphasis on lateral diffusion.Abbreviations DCMU 3-(3,4-dichlorophenyl)-1,1-dimethylurea - EDTA Ethylenediaminetetracetate - Hepes N-2-hydroxyethyl piperazine-N-2-ethanesulphonic acid - NADP nicotinamide adenine dinucleotide phosphate     

Micropropagation of the rare species Stylidium coroniforme and other Stylidium species

The number of plants in the gazetted rare species Stylidium coroniforme was increased through micropropagation. A method was first developed using the common species S. brunonianum. It was found that for both species, rapid propagation could be obtained by excising shoots from sterile seedlings and inducing shoot proliferation on Murashige and Skoog medium supplemented with 1 M BAP. Rooting was achieved using 1 M IBA and over 100 plants of each species were successfully established in soil. Leaf pieces could also be used to initiate cultures. In media with 20–25 M BAP and 1–5 M IBA, leaf pieces of S. brunonianum, S. piliferum, S. caricifolium and S. crassifolium produced adventitious buds, thus providing another method of micropropagation.     

Seasonal variations in hematocrit, red cell hemoglobin and nucleoside triphosphate concentrations, in the European eel Anguilla anguilla

Eels acclimatized in nature show a significant annual variation in erythrocytic guanosine triphosphate (GTP) concentration, temperature range 0.5-17 degrees C. A similar but smaller annual variation is also present in eels acclimated in the laboratory at constant temperature, 17 degrees C. Hematocrit and blood oxygen capacity showed no seasonal variation. Natural minimal and maximal red cell GTP concentrations were found at the end of the dormancy period (March) and in the late summer, respectively. Furthermore, a chronological connection of the erythrocytic GTP values versus ambient temperature, in the natural environment, demonstrates a hysteresis. This allows for a prediction of a slowly progressing enhancement of the temperature effect on Hb-O2 binding throughout autumn, whereas a relatively fast and pronounced enhancement predictably takes place in spring (April-May) coincident with the "awakening" of the eels.     

Characterization of an oxygen-tolerant cell line derived from Chinese hamster ovary

To study the cellular defense mechanism against oxygen toxicity, an oxygen-tolerant cell line from Chinese hamster ovary (CHO) was obtained by multistep adaptation to increased O2 levels. The hyperoxia-adapted (HA) cells were able to proliferate under an atmosphere of 99% O2/1% CO2, an O2 tension lethal to the parental (control) cells. When grown under normoxic conditions (20% O2/1% CO2/79% N2) the cells remained tolerant for at least 8 weeks, suggesting a genetic basis for the oxygen tolerance. Compared to the parental cells, the HA cells were irregularly shaped, had larger mitochondria, contained more lipid droplets and showed a reduced growth rate. Ultrastructural morphometry revealed a 1.8-fold (p less than 0.001) increase of the mitochondrial volume fraction in the HA cells, resulting from an increase in both number and average volume of the mitochondria. The volume fraction of peroxisomes was increased over two-fold in the HA cells, as appeared from a approximately 1.9-fold (p less than 0.001) increase in number and a 1.2-fold (p less than 0.025) increase in size. There was no evidence for ultrastructural damage in the HA cells. Specific activities of antioxygenic enzymes were considerably higher in the HA cells compared to controls: CuZn-superoxide dismutase, X 2.5; Mn-superoxide dismutase, X 2.1; catalase, X 4.0; glutathione peroxidase, X 1.9. Oxygen tolerance in CHO cells is therefore associated with increased levels of antioxygenic enzymes, confirming the proposed important role of these enzymes in the defense against oxygen toxicity.     

Isolation and identification of two isomeric trihydroxy octadecenoic acids with prostaglandin E-like activity from onion bulbs (Allium cepa)

Two fractions with prostaglandin E-like activity were isolated from onion (Allium cepa) by using XAD-2 adsorption, silicic acid column chromatography and thin layer chromatography. The fractions were analyzed by gas chromatography/mass spectrometry and were characterized as isomeric mixtures of 9,10,13-trihydroxy-11-octadecenoic and 9,12,13-trihydroxy-10-octadecenoic acid, which are lipoxygenase metabolites of linoleic acid. Bio-assay, for which cascade superfusion was used and the rabbit coeliac and mesenteric arteries and the rat fundus strip were employed as assay organs, was utilized to monitor the bio-active profile throughout the isolation procedures. The activity of 1 microgram of the pharmacologically active fractions T1 and T2 was found to be equivalent to that of respectively 1.33 and 0.63 ng of prostaglandin E2.     

Cyclic adenosine 3'5' monophosphate stimulates prostaglandin E production by human adherent synovial cells

Production of prostaglandin E (PGE) by rheumatoid synovium appears important to regulation of the pathologic process in rheumatoid arthritis. Cells derived from human synovium by proteolytic digestion produce large amounts of PGE which in turn can elevate synovial cell cAMP levels and inhibit cell proliferation. Data presented here indicate that cAMP can further increase production of PGE from adherent synovial cells (ASC). PGE production occurs over 12-72 hr and is not due to the ability of cAMP to inhibit cell proliferation. Exposure of cells to cAMP results in increased release of 3H arachidonic acid from precursors but not in activation of the cyclooxygenase enzyme. This phenomenon suggests the presence in adherent synovial cells of a mechanism for amplifying PGE production.     

Peroxidative oxidation of bilirubin during prostaglandin biosynthesis

The peroxidative oxidation of bilirubin has been characterized in the ram seminal vesicle microsomal system. The oxidation was monitored by following the loss in absorbance of bilirubin at 440 nm. Bilirubin behaves as a peroxidase substrate for prostaglandin H synthase. The oxidation may be initiated by the addition of arachidonic acid or peroxides to incubations containing ram seminal vesicle microsomes and bilirubin, and is sensitive to inhibition by reduced glutathione. The arachidonate-dependent oxidation, but not the peroxide-initiated case, is inhibited by indomethacin. Similar results were obtained using microsomal preparations from mouse, rat, and pig lungs. Spectral and chromatographic examination of the products of bilirubin oxidation in the ram seminal vesicle system demonstrate that biliverdin is produced in this system by the dehydrogenation of bilirubin, but that this product accounts for only about 15% of the bilirubin consumed. Biliverdin itself is not oxidized in this system. At least three highly polar, fluorescent products also are formed from bilirubin. Though not identified, these polar products differ markedly in chromatographic behavior from the major fluorescent products obtained following the singlet oxygen oxidation or the autoxidation of bilirubin.     

B lymphocyte receptors and polyphosphoinositide degradation

Resting B lymphocytes can be activated and induced to proliferate by antibodies against their antigen receptors (anti-lg). We demonstrate an early increase in the level of [3H]inositol trisphosphate in [3H]inositol-labeled murine B cells, which suggests breakdown of phosphatidylinositol bisphosphate by phospholipase C. In line with this, the level of [3H]1,2-diacylglycerol was also elevated after incubation of [3H]arachidonic-acid-labeled B cells with anti-Ig. Anti-lg also caused a rapid increase in the level of cytosolic Ca2+ in B cells. In contrast, two other polyclonal B cell activators, lipopolysaccharide and phorbol myristate acetate, failed to induce any of these effects. Our results suggest that anti-lg may induce B cell growth via phosphoinositide degradation and Ca2+ mobilization, and that phorbol myristate acetate, and possibly lipopolysaccharide, bypass these initial events.     

Evidence from cDNA clones that the rat leukocyte-common antigen (T200) spans the lipid bilayer and contains a cytoplasmic domain of 80,000 Mr

The leukocyte-common antigen (L-CA or T200) includes a family of lymphoid and myeloid cell surface glycoproteins with apparent molecular weights from 180,000 to 240,000. We report a partial protein sequence for thymocyte L-CA containing 1073 amino acids predicted from cDNA clones isolated using an oligonucleotide probe. Only one segment (residues 347-368) is likely to cross the membrane, and peptide data suggest that sequences N-terminal to this are outside the cell, with residues 369-1073 inside. The cytoplasmic domain includes possible phosphorylation sites and an internal homology between residues 385-671 and 676-986. Analysis of B lymphocyte cDNA clones suggests that B cell and thymocyte mRNAs are identical in 3' sequences, but size differences in Northern blots suggest 5' sequences may differ.