Additions to the lichen family Pannariaceae in Ecuador

Collections from high altitudes (3840–5100 m a.s.l.) have added several species to the Pannariaceae of Ecuador: Fuscopannaria praetermissa, Pannaria hookeri, Psoroma paleaceum and Psoroma tenue are new to the Andes, and phytogeographic consequences of these are discussed. The following new taxa are described: Parmeliella corallina P. M. Jørg. & Palice, Parmeliella psoromoides P. M. Jørg. & Palice, Psoroma cinnamomeum ssp. andinum P. M. Jørg. & Palice and Santessoniella macrospora P. M. Jørg. & Palice. They are part of a high‐andean element which is not well known and is indicative of a migration route between the polar regions. In addition, two species with associated cyanobacteria, as the primary or secondary symbiont, are reported for the first time from South America: Thelignya lignyota (Wahlenb.) P. M. Jørg. & Henssen and Pilophorus cereolus (Ach.) Th. Fr, both originating from the Northern Hemisphere.     

Heliothrix oregonensis,gen. nov., sp. nov., a phototrophic filamentous gliding bacterium containing bacteriochlorophyll a

An unusual filamentous, gliding bacterium was found in a few hot springs in Oregon where it formed a nearly unispecific top layer of microbial mats. It contained a bacteriochlorophyll a-like pigment and an abundance of carotenoids. There were no chlorosomes or additional chlorophylls. The organism was aerotolerant and appeared to be photoheterotrophic. It was successfully co-cultured with an aerobic chemoheterotroph in a medium containing glucose and casamino acids. Although it has many characteristics in common with the genus Chloroflexus, the lack of chlorosomes and bacteriochlorophyll c and the aerobic nature of this organism indicate that it should be placed in a new genus. This conclusion is supported by 5S rRNA nucleotide sequence data.     

Quantitative Determination of Bovine Plasma Fibrinogen by Rocket Immunoelectrophoresis and by Refractometry after Heat-Precipitation

A standard syneresis method for measuring plasma fibrinogen concentrations in cattle was compared with a rocket Immunoelectrophoresis method and with a simple refractometer method; the correlations between the results obtained by the standard method and by the other 2 methods were high (r = 0.94 and 0.89 respectively, p < 0.001). The immunoelectrophoretic method is efficient and simple to perform. In contrast with the standard syneresis method, the other methods allow for the fibrinogen degradation products produced by fibrinolysis in vitro; they can therefore tolerate longer sample storage before analysis. The refractometer method is exceptionally simple and rapid and can be recommended for use under field conditions.     

Genetic engineering applied to the development of vaccines

The simplest application of the modern genetic manipulation methods to vaccine development is the expression in microbial cells of genes from pathogens that encode surface antigens capable of inducing neutralizing antibodies in the host of the pathogen involved. This procedure has been exploited successfully for development of a vaccine against hepatitis B virus (HBV) that is now widely used. Similar approaches have been directed towards formulations for immunization against several other animal and human diseases and some of these preparations are now presently in trials. Of no less importance is the impact of biotechnology in providing reagents for fundamental studies of topics such as the determination of virulence, antigenic variation, virus receptors and the immunological response to viral antigens. The core antigen of HBV is a good example of a product of genetic engineering that is a valuable diagnostic reagent, and that is finding important use in immunological studies of particular pertinence to vaccine development.     

Shape and location of eukaryotic initiation factor eIF-2 on the 40S ribosomal subunit of rat liver. Immunoelectron-microscopic and hydrodynamic investigations

The location of initiation factor eIF-2 and of its subunits in quaternary initiation complexes (40S-ribosomal-subunit.eIF-2. GuoPP[CH2]P.Met-tRNAf) was investigated by immunoelectron microscopy. Quaternary complexes were fixed with glutaraldehyde and reacted with affinity-purified polyclonal antibodies against eIF-2 alpha, eIF-2 beta or eIF-2 gamma. The dimeric immune complexes obtained by sucrose gradient centrifugation were investigated electron microscopically after negative staining. Antibody-binding sites were observed on the interface side of the 40S ribosomal subunit in the region between the 'head' and the 'body' (neck region) of the 40S ribosomal subunit. Within this region, eIF-2 alpha points to the rear side, whereas eIF-2 beta and eIF-2 gamma point to the frontal side of the 40S subunit indicating an elongated shape of eIF-2 about 15 nm long. By analytical ultracentrifugation of isolated eIF-2 the sedimentation and diffusion coefficients were determined to be 6.54 S and 4.74 x 10(-7) cm2/s respectively. From these data, a molar mass of 122.4 kg/mol and a dry volume of 147.4 nm3 were calculated. For the shape of eIF-2 a prolate ellipsoid of revolution is assumed with a maximal length of about 15 nm and with an axial ratio of about 1:3.5. This conclusion is further confirmed by a calculated frictional ratio of 1.37 and a Stokes radius of about 4.54 nm.     

Membrane-trafficking RabA4c involved in the effect of glycine betaine on recovery from chilling stress in Arabidopsis

Glycine betaine (GB) can confer tolerance to several types of stress at low concentrations, either after application to plants or in transgenics engineered to overproduce GB. Based on earlier studies on levels of GB in plants and evidence for effects on gene expression, we hypothesized that at least part of this effect could be ascribed to the activation of the expression of stress tolerance genes. Using a strategy based on high-throughput gene expression analysis with microarrays followed by confirmation with northern blots, we identified Arabidopsis genes upregulated in roots that reinforce intracellular processes protecting cells from oxidative damage and others that appear to be involved in reinforcing a scavenging system for reactive oxygen species (ROS) in cell walls. Upregulated genes in roots include those for the membrane-trafficking RabA4c, the root-specific NADPH-dependent ferric reductase (FRO2) localized to the plasma membrane, mitochondrial catalase 2 and the cell wall peroxidase ATP3a. Comparative studies with wild-type Arabidopsis and knockout mutants for the membrane-trafficking RabA4c gene demonstrated that the mutants respond only slightly to GB, if at all, compared with wild-type in relation to root growth recovery after chilling stress, demonstrating the role of RabA4c in relation to the GB effect. The results point toward links between oxidative stress, gene expression, membrane trafficking and scavenging of ROS such as superoxide and hydrogen peroxide in relation to GB effects on chilling tolerance in plants.     

Comparison of gas chromatography-mass spectrometry,radioimmunoassay and bioassay for the quantification of gibberellin A9 in norway spruce (Picea abies (L.) Karst.)

Quantitative estimates of gibberellin A₉ in Norway spruce extracts obtained by gas chromatography-mass spectrometry, radioimmunoassay (RIA_ and bioassay were compared after successive purifications of the extracts. The extracts were assayed in several dilutions with and without the addition of standard gibberellin A₉, thus showing the effect of extract components on the response of the assays. Radioimmunoassay produced estimates comparable to gas chromatography-mass spectrometry after one purification step by high-performance liquid chromatography. Extracts purified by polyvinylpyrrolidone-column chromatography and solvent partitioning but not high-performance liquid chromatography resulted in inaccurate RIA estimates. The performance of the RIA could be monitored by logit-log transformations of the standard curve and extract dilution curve and by calculating the slope of the standard addition curve. It was, however, not possible to correct for the interference caused by extract components by the standard addition procedure. Quantifications by Tan-ginbozu dwarf-rice bioassay were accurate, but a large and unpredictable variation makes it unsuitable for quantitative determinations.Abbreviations FW fresh weight - GA₉ gibberellin A₉ - GA₉–Me methylated GA₉ - GC-MS gas chromatography-mass spectrometry - HPLC high performance liquid chromatography - MID multiple-ion detection - RIA radioimmunoassay