K2P18.1 translates T cell receptor signals into thymic regulatory T cell development

It remains largely unclear how thymocytes translate relative differences in T cell receptor (TCR) signal strength into distinct developmental programs that driv...     

Bombesin-like peptides in human small cell carcinoma of the lung

The nature of bombesin-like immunoreactive peptides was studied in extracts of small cell carcinoma of the human lung. Three peaks, I, II and III, designated by their increasing retention times, were separated by reversed-phase high performance liquid chromatography (HPLC) with trifluoroacetic acid (TFA) as counter ion. None of the peaks corresponded to bombesin. Peak III was eluted at the same position as porcine gastrin releasing peptide (GRP) but was separated from it in another reversed-phase system using heptafluorobutyric acid (HFBA). Peak II material eluted in the position of bombesin in the HFBA system but not in the TFA system. The elution position of Peak I corresponded to that of the carboxyl terminal fragments of GRP, i.e. GRP18-27 and GRP19-27. This correspondence was observed in each of the reversed-phase and gel filtration systems used. The Peak III peptide was converted to peak I after incubation with trypsin. It was reasoned that this conversion could be one of the steps in the processing of bombesin-like peptides in human small cell carcinoma.     

Enhancement in the viability and biosensing activity of freeze-dried recombinant bioluminescent bacteria

The genetically-engineeredEscherichia coli strain, DPD2540, which contains afabA::luxCDABE fusion gene, gives a bioluminescent output when membrane fatty acid synthesis is needed. For more practical application of this strain in the field as biosensor, freeze-drying was adopted. A 12% sucrose solution with Luria-Bertani (LB) broth, as determined by the viability after freeze-drying, was found to be the most effective composition for lyophilization solution among various compositions tested. Rapid freezing with liquid nitrogen also gave the best viability after freeze-drying as compared to samples frozen at −70°C and −20°C. The biosensing activities of the cells showed a greater sensitivity when the cells from the exponential phase were freeze-dried. Finally, the optimum temperature for use of the freeze-dried cells in the biosensor field was determined.     

9-Methyl-β-carboline-induced cognitive enhancement is associated with elevated hippocampal dopamine levels and dendritic and synaptic proliferation

β-Carbolines (BCs) belong to the heterogenous family of carbolines, which have been found exogenously, that is, in various fruits, meats, tobacco smoke, alcohol and coffee, but also endogenously, that is, blood, brain and CSF. These exogenous and endogenous BCs and some of their metabolites can exert neurotoxic effects, however, an unexpected stimulatory effect of 9-methyl-β-carboline (9-me-BC) on dopaminergic neurons in primary mesencephalic cultures was recently discovered. The aim of the present study was to extend our knowledge on the stimulatory effects of 9-me-BC and to test the hypothesis that 9-me-BC may act as a cognitive enhancer. We found that 10 days (but not 5 days) of pharmacological treatment with 9-me-BC (i) improves spatial learning in the radial maze, (ii) elevates dopamine levels in the hippocampal formation, and (iii) results after 10 days of treatment in elongated, more complex dendritic trees and higher spine numbers on granule neurons in the dentate gyrus of 9-me-BC-treated rats. Our results demonstrate that beyond its neuroprotective/neurorestorative and anti-inflammatory effects, 9-me-BC acts as a cognitive enhancer in a hippocampus-dependent task, and that the behavioral effects may be associated with a stimulatory impact on hippocampal dopamine levels and dendritic and synaptic proliferation.     

The Arabidopsis METACASPASE9 Degradome

Metacaspases are distant relatives of the metazoan caspases, found in plants, fungi, and protists. However, in contrast with caspases, information about the physiological substrates of metacaspases is still scarce. By means of N-terminal combined fractional diagonal chromatography, the physiological substrates of METACASPASE9 (MC9; AT5G04200) were identified in young seedlings of Arabidopsis thaliana on the proteome-wide level, providing additional insight into MC9 cleavage specificity and revealing a previously unknown preference for acidic residues at the substrate prime site position P1′. The functionalities of the identified MC9 substrates hinted at metacaspase functions other than those related to cell death. These results allowed us to resolve the substrate specificity of MC9 in more detail and indicated that the activity of phosphoenolpyruvate carboxykinase 1 (AT4G37870), a key enzyme in gluconeogenesis, is enhanced upon MC9-dependent proteolysis.     

The Translational Apparatus of Plastids and Its Role in Plant Development

Chloroplasts （plastids） possess a genome and their own machinery to express it. Translation in plastids occurs on bacterial-type 70S ribosomes utilizing a set of tRNAs that is entirely encoded in the plastid genome. In recent years, the components of the chloroplast translational apparatus have been intensely studied by proteomic approaches and by reverse genetics in the model systems tobacco （plastid-encoded components） and Arabidopsis （nucleus-encoded components）. This work has provided important new insights into the structure, function, and biogenesis of chloroplast ribosomes, and also has shed fresh light on the molecular mechanisms of the translation process in plastids. In addition, mutants affected in plastid translation have yielded strong genetic evidence for chloroplast genes and gene products influencing plant develop- ment at various levels, presumably via retrograde signaling pathway（s）. In this review, we describe recent progress with the functional analysis of components of the chloroplast translational machinery and discuss the currently available evidence that supports a significant impact of plastid translational activity on plant anatomy and morphology.     

Substrate properties of C1 inhibitor Ma (alanine 434----glutamic acid). Genetic and structural evidence suggesting that the P12-region contains critical determinants of serine protease inhibitor/substrate status

The serine protease inhibitor (serpin) C1 inhibitor inactivates enzymes involved in the regulation of vascular permeability. A patient from the Ma family with the genetic disorder hereditary angioedema inherited a dysfunctional C1 inhibitor allele. Relative to normal plasma, the patients's plasma contained an additional C1 inhibitor immunoreactive band, which comigrated with normal C1 inhibitor cleaved by plasma kallikrein, C1s, or factor XIIa. C1 inhibitor Ma did not react with a monoclonal antibody to a neoepitope that is present in complexed and cleaved normal C1 inhibitor, suggesting conformational differences between cleaved normal C1- inhibitor and cleaved C1 inhibitor Ma. Molecular cloning and sequencing of exon 8 of the C1 inhibitor Ma allele revealed a single C to A mutation, changing alanine 434 to glutamic acid. Ala 434 of C1 inhibitor aligns with the P12 residue of the prototypical serpin alpha 1-antitrypsin. The P12 amino acid of all inhibitory serpins is alanine, and it is present in a highly conserved region on the amino-terminal side of the serpin-reactive center loop. Whereas normal C1 inhibitor expressed by transfected COS-1 cells formed complexes with and was cleaved by kallikrein, fXIIa, and C1s, COS-1-expressed Ala434---Glu C1 inhibitor was cleaved by these enzymes but did not form complexes with them. These results, together with evidence from other studies, suggest that serpin protease inhibitor activity is the result of protein conformational change that occurs when the P12 region of a serpin moves from a surface location, on the reactive site loop of the native molecule, to an internal location within sheet A of the complexed inhibitor.     

2,3-Diaminopyridine as a platform for designing structurally unique nonpeptide bradykinin B1 receptor antagonists

A novel class of 2,3-diaminopyridine bradykinin B1 receptor antagonists is disclosed. Structure-activity relationship studies (SARs) that led to compounds with significantly improved potency and pharmacokinetic properties relative to the lead compound are described.     

Alternative complex formation of the Ca-regulated protein kinase CIPK1 controls abscisic acid-dependent and independent stress responses in Arabidopsis

Intracellular release of calcium ions belongs to the earliest events in cellular stress perception. The molecular mechanisms integrating signals from different environmental cues and translating them into an optimized response are largely unknown. We report here the functional characterization of CIPK1, a protein kinase interacting strongly with the calcium sensors CBL1 and CBL9. Comparison of the expression patterns indicates that the three proteins execute their functions in the same tissues. Physical interaction of CIPK1 with CBL1 and CBL9 targets the kinase to the plasma membrane. We show that, similarly to loss of CBL9 function, mutation of either CBL1 or CIPK1 renders plants hypersensitive to osmotic stress. Remarkably, in contrast to the cbl1 mutant and similarly to the cbl9 mutant, loss of CIPK1 function impairs abscisic acid (ABA) responsiveness. We therefore suggest that, by alternative complex formation with either CBL1 or CBL9, the kinase CIPK1 represents a convergence point for ABA-dependent and ABA-independent stress responses. Based on our genetic, physiological and protein-protein interaction data, we propose a general model for information processing in calcium-regulated signalling networks.     

Monitoring and classification of PAH toxicity using an immobilized bioluminescent bacteria

An immobilized recombinant bioluminescent Escherichia coli strain, harboring a lac::luxCDABE fused plasmid, which shows lower bioluminescence levels when cellular metabolism is inhibited, was used to monitor the cellular toxicity of polycyclic aromatic hydrocarbons (PAHs). PAHs, classified as pericondensed (PCPAHs) or catacondensed (CCPAHs) according to their molecular structures, were differentiable according to the response of this biosensor. Only CCPAHs were found to cause cellular toxicity, resulting in a dose-dependent decrease in the bioluminescent output. The induction of cellular toxicity by CCPAHs and PCPAHs was compared with acute toxicity predictions obtained using the quantitative structure-activity relationship (QSAR) model. A good relationship was obtained between the toxicities determined with the bioluminescent response of the immobilized bacterium GC2 and the QSAR model. It was also found that the present study offers a new method of predicting the cellular toxicities of CCPAHs or PCPAHs using this biosensor.