Extraction and genetic control of two new water-soluble proteins of mature barley seed

This paper describes the genetic control of two new water-soluble proteins in barley. Water-soluble proteins (WSPs) of mature barley seed form part of the albumin/globulin class of seed proteins. They can be extracted from hand-milled grain with water, though some WSPs are more efficiently extracted with a solution of 10 mM dithiothreitol. Polymorphisms for WSPs were detected in isoelectric focusing gels incorporating various ampholine combinations. Two new controlling genes (Wsp4 andWsp5) have been identified and located using wheat/barley chromosome addition lines and barley doubled haploids.Wsp4 is located on chromosome 2 (2H), andWsp5 was found to be tightly linked toWsp2 on the long arm of chromosome 7 (5HL). Segregation of a sixth gene (Wsp6) is also described, but this has not been mapped. The results are discussed with respect to other previously mappedWsp loci.This work was funed by the Scottish Office of Agriculture and Fisheries Department and the Agricultural and Food Research Council.     

Changes in Metabotropic Glutamate Receptor mRNA Levels Following Global Ischemia: Increase of a Putative Presynaptic Subtype (mGluR4) in Highly Vulnerable Rat Brain Areas

Abstract: Metabotropic glutamate receptors mediate their intracellular response by coupling to G proteins and may be divided into three subfamilies: mGluR1 and mGluR5, which stimulate phosphatidylinositol hydrolysis; mGluR2 and mGluR3, which are negatively coupled to cyclic AMP formation; and mGluR4 and mGluR6, which also inhibit forskolin-stimulated cyclic AMP formation. The mGluR4 subtypes may represent l -2-amino-4-phosphonobutyrate-sensitive presynaptic autoreceptors, and two alternatively spliced variants of the mGluR4 coding for two receptors with different C termini have been identified. Using in situ hybridization, we measured the levels of mGluR1–mGluR5 mRNA in regions of the rat brain 24 h after transient global ischemia, a time point when no neuronal damage can yet be observed morphologically. In the hippocampus, the mRNA levels for mGluR1, mGluR2, and mGluR5 were decreased, mGluR3 mRNA levels were unchanged, and the mGluR4 mRNA levels were strongly increased. The strongest increase appeared to be in the mRNA encoding mGluR4b. The mGluR4 mRNA was also increased in the parietal cortex, whereas the ventral posteromedial thalamic nucleus showed a small decrease in its mRNA content. These results suggest that vulnerable neurons react to an increased extracellular glutamate concentration by differential regulation of the mRNA for pre- and postsynaptically located metabotropic glutamate receptors.     

The evolutionary origin of the 35 kb circular DNA of Plasmodium falciparum: new evidence supports a possible rhodophyte ancestry

In common with other Apicomplexan parasites, Plasmodium falciparum carries two extrachromosomal DNAs, one of which, the 6 kb element, is undoubtedly mitochondrial. The second, generally referred to as the 35 kb circle, is of unknown provenance, but the nature and organization of its genetic content makes a mitochondrial association unlikely and the molecule has features reminiscent of plastid genomes. We now report the occurrence on the circle of an open reading frame specifying a predicted 470 amino acid protein that shares more than 50% identity with a gene currently known only on the plastome of red algae. This high degree of conservation confirms the 35 kb circle's plastid ancestry, and we speculate that it may have originated from the rhodoplast of an ancient red algal endosymbiont in the progenitor of the Apicomplexa.     

Studies on plant regeneration from cotyledonary protoplasts in Brassica campestris

Protoplasts isolated from both 7-day-old light-grown and 4-day-old dark/dim light-grown cotyledons of four Brassica campestris varieties (Arlo, Sonja, Bunyip and Wonk Bok) were cultured in three liquid media: modified K8P, modified MS and modified Pelletier's B to compare the capacities for cell division and plant regeneration. Following cell wall regeneration the cultured protoplasts from dark/dim light-grown cotyledons of four varieties showed rapid division and high frequency of cell division compared with those isolated from light-grown cotyledons. The frequencies of cell division were significantly influenced by varieties and culture media but only in cultured protoplasts isolated from dark/dim light-grown cotyledons. The interaction between varieties and media was also significant. Cell colonies formed within 7–14 days in protoplast cultures from dark/dim light-grown cotyledons, and calli subsequently grown on a solid medium developed shoots when transferred onto a regeneration medium. Three of four tested varieties (Arlo, Sonja and Bunyip) showed shoot regeneration within 2–3 months after protoplast isolation, with a high degree of reproducibility in Arlo and Bunyip. Regenerated shoots, which were induced to root on half-strength MS medium with 0.1 mg.l^–1 IBA, survived in soil and grew to produce siliques and set viable seeds in the greenhouse. The present report is the first to document the production of regenerated plants that set seeds in Brassica campestris from cotyledonary protoplasts.Abbreviations BAP benzylaminopurine - CPW Composition of Protoplast Washing-solution - 2,4-D 2,4-dichlorophenoxyacetic acid - EDTA ethylenediamine-tetraacetic acid - GA₃ gibberellic acid - IBA indole-3-butyric acid - IAA indole-3-acetic acid - MS Murashige and Skoog medium - NAA -naphthaleneacetic acid - KT kinetin - FDA fluorescein diacetate - SDS sodium dodecyl sulfate     

The role of growth factors in gastrointestinal cell proliferation.

The epithelial lining of the gastrointestinal (GI) tract is in a state of continuous cell renewal, and the proliferating and differentiating/differentiated cell populations are spatially clearly demarcated. Members of the epidermal growth factor (EGF) family of peptides, the trefoil peptides and enteroglucagon appear to be the most important enterotrophic molecules for both normal cell renewal and healing after cell damage. Transforming growth factor-a (TGF-a) appears to be the primary physiological ligand for the EGF receptor (EGFR), promoting normal cell renewal, and TGF-a/EGFR are part of an autocrine loop in many intestinal cancers. In response to damage, a differentiating cell lineage arises from adjacent epithelium secreting EGF, TGF-a and trefoil peptides; this may be viewed as part of a ‘repair kit’ in damaged endodermally-derived tissue.     

Sulphate/proton cotransport in plasma-membrane vesicles isolated from roots of Brassica napus L.: increased transport in membranes isolated from sulphur-starved plants

The characteristics of sulphate uptake into right-side-out plasma-membrane vesicles isolated from roots of Brassica napus L., Metzger, cv. Drakkar, and purified by aqueous polymer two-phase partitioning, were investigated. Sulphate uptake into the vesicles was driven by an artificially imposed pH gradient (acid outside), and could be observed for 5–10 min before a plateau was reached and no further net uptake occurred. The uptake was partially inhibited in the presence of depolarizing agents and little uptake was observed in the absence of an imposed pH gradient. Uptake was strongly pH-dependent, being greatest at more acidic pH. After imposition of a pH gradient, the capacity for uptake decreased slowly (t1/2>10 min). The uptake had a high-affinity component which was strongly dependent on the external proton concentration (K _m=10μM at pH 5.0, 64 μM at pH 6.5). The K _m for protons varied from 0.4–1.9 μM as the sulphate concentration was reduced from 33 to 1 μM. A low-affinity component was observed which could be resolved at low temperatures (0 °C). Microsomal membranes that partitioned into the lower phase of the two-phase system gave no indication of high-affinity sulphate transport. Sulphate uptake into plasma-membrane vesicles isolated from sulphur-starved plant material was approximately twofold greater than that observed in those isolated from sulphate-fed plant material. Isolated vesicles therefore mirror the well-known in-vivo response of roots, indicating an increase in the number of transporters to be, at least in part, the underlying cause of derepression.     

Phenylalkyl ketones as potent reversible inhibitors of interleukin-1β converting enzyme

Phenylalkyl ketones are potent reversible inhibitors of interleukin-1β converting enzyme (ICE). The extended alkyl chain ketones AcTyrValAlaAspCO(CH₂)_nPh display increased potency over the simple aryl ketone. In particular, the tetrapeptide AcTyrValAlaAspCOPh has a K_i of 10μM while AcTyrValAlaAspCO(CH₂)₅Ph has a K_i of 18.5nM.     

The synthesis and biochemical evaluation of new A1 selective adenosine receptor agonists containing 6-hydrazinopurine moieties

The synthesis and SAR of a series of novel derivatives of N-aminoadenosine is described, along with their in vitro effects in biochemical assays. The rat brain A₁ adenosine receptor binding of these compounds is very dependent upon the purine 2-substituent. The novel agonist, 2-chloro-N-[4-(phenylthio)-1-piperidinyl]adenosine, exhibits a L_i value for A₁ receptor binding of <1 nM.     

Membrane inlet—ion mobility spectrometry with automatic spectra evaluation as online monitoring tool for the process control of microalgae cultivation

The cultivation of algae either in open raceway ponds or in closed bioreactors could allow the renewable production of biomass for food, pharmaceutical, cosmetic, or chemical industries. Optimal cultivation conditions are however required to ensure that the production of these compounds is both efficient and economical. Therefore, high-frequency analytical measurements are required to allow timely process control and to detect possible disturbances during algae growth. Such analytical methods are only available to a limited extent. Therefore, we introduced a method for monitoring algae release volatile organic compounds (VOCs) in the headspace above a bioreactor in real time. This method is based on ion mobility spectrometry (IMS) in combination with a membrane inlet (MI). The unique feature of IMS is that complete spectra are detected in real time instead of sum signals. These spectral patterns produced in the ion mobility spectrum were evaluated automatically via principal component analysis (PCA). The detected peak patterns are characteristic for the respective algae culture; allow the assignment of the individual growth phases and reflect the influence of experimental parameters. These results allow for the first time a continuous monitoring of the algae cultivation and thus an early detection of possible disturbances in the biotechnological process.