p185, an immunodominant epitope, is an autoantigen mimotope

An immunodominant peptide (p185(378-394)) derived from the c-erbB2 gene product, was recognized by an anti-DNA antibody, B3, and importantly by two classical DNA-binding proteins, Tgo polymerase and Pa-UDG. These reactivities were inhibited by DNA, confirming that the peptide mimicked DNA. BALB/c mice immunized with p185(378-394) developed significant titers of IgG anti-dsDNA antibodies. Screening of 39 human lupus sera revealed that 5% of these sera possessed reactivity toward p185(378-394). Representative mouse and human sera with anti-p185(378-394) reactivity bound intact p185, and this binding was inhibited by dsDNA. This is the first demonstration of a naturally occurring autoantigen mimotope. The present study identifies a potential antigenic stimulus that might trigger systemic lupus erythematosus in a subset of patients.     

Oehlkers, friedrich, erblichkeitsforschung an Pflanzen

Ohne Zusammenfassung     

Soymetide,an immunostimulating peptide derived from soybean beta-conglycinin,is an fMLP agonist

A tridecapeptide (MITLAIPVNKPGR) that stimulates phagocytosis of human neutrophils was isolated from a trypsin digest of soybean proteins. This peptide is derived from the soybean β-conglycinin ′ subunit and was named soymetide-13. The N-terminal methionine residue of soymetide-13 is essential for its activity, and removal of C-terminal residues revealed that soymetide-4 (MITL) is the minimal structure required for phagocytosis stimulation. Although they are not formylated at their N-termini, soymetides have a weak affinity for the N-formyl-methionyl-leucyl-phenylalanine (fMLP) receptor and their phagocytosis-stimulating activity is inhibited by the fMLP antagonist Boc-MLP. Interestingly, soymetide-4 promotes tumor necrosis factor production at a higher level than soymetide-13 following oral administration in mice.     

Ataxia-telangiectasia, an evolving phenotype

Ataxia-telangiectasia (A-T) is a progressive neurodegenerative disorder, with onset in early childhood and a frequency of approximately 1 in 40,000 births in the United States. A-T is seen among all races and is most prominent among ethnic groups with a high frequency of consanguinity. The syndrome includes: progressive cerebellar ataxia, dysarthric speech, oculomotor apraxia, choreoathetosis and, later, oculocutaneous telangiectasia. Immunodeficiency with sinopulmonary infections, cancer susceptibility (usually lymphoid), and sensitivity to ionizing radiation are also characteristic. Laboratory findings include: (1) elevated alphafetoprotein (AFP), (2) cerebellar atrophy on magnetic resonance imaging, (3) reciprocal translocations between chromosomes 7 and 14 in lymphocytes, (4) absence or dysfunction of the ATM protein, (5) radiosensitivity, as demonstrated by colony survival assay (CSA), and (6) mutations in the ATM gene. The latter are usually truncating or splicing mutations; approximately 10% are missense mutations. Mutations are found across the entire gene. Almost all recurring mutations are found on unique haplotypes that represent founder effects and ancestral relationships between patients. In addition to radiosensitivity and sensitivity to radiomimetic chemicals, the phenotype of A-T cells includes defective damage-induced activation of the cell cycle checkpoints at G1, S and G2/M. With the aid of molecular testing, A-T can now be distinguished from other autosomal recessive cerebellar ataxias (ARCAs) such as Friedreich ataxia, Mre11 deficiency (AT-like disease), and the oculomotor apraxias 1 (aprataxin deficiency) and 2 (senataxin deficiency). Other "A-T variants" include: (1) Nijmegen breakage syndrome (NBS) or nibrin/Nbs1 deficiency, with microcephaly and mental retardation but without ataxia, apraxia, or telangiectasia, and 2) A-T(Fresno), a phenotype that combines features of both NBS and A-T, with mutations in the ATM gene. The term "A-T variant" has a diminishing usefulness.     

Using an electro-microchip, a nanogold probe, and silver enhancement in an immunoassay

This paper presents a novel immunoassay that uses an electro-microchip to detect the immuno-reaction signal, gold nanoparticles (ANPs) as a label of antigen or antibody and as a catalyst for silver precipitation, and the silver enhancement reaction to magnify the detection signal. This study is based on the direct immunoassay (two-layer format) and the sandwich immunoassay (three-layer format). The ANPs were introduced into the electro-microchip by the specific binding of the antibodies-ANPs conjugates and then were coupled with silver enhancement to produce black spots of silver metal. The silver precipitation constructs a "bridge" between two electrodes of the electro-microchip allowing electrons to pass. The variation of impedance can be easily measured with a commercial LCR meter. Various gap sizes (20, 50, 100, and 200 microm) of the electrodes of electro-microchips were designed for the sensitivity study. The experimental data show that a chip with a 20microm gap has the highest sensitivity. There was a significant difference in impedance between the experiment sample and the negative control after 10 min of reaction time. The proposed method requires less time and fewer steps than the conventional enzyme-linked immunosorbent assay (ELISA). In addition, it shows a high detection sensitivity (10 microg/mL of 1st antibody (IgG) immobilized on slides and 1 ng/mL of antigen (protein A)). There is a clear distinction between the signal intensity and the logarithm of the sample concentration. The proposed new immunoassay method has potential applications in proteomics research and clinical diagnosis.     

MDM2, an introduction

The murine double minute 2 (mdm2) gene encodes a negative regulator of the p53 tumor suppressor. Amplification of mdm2 or increased expression by unknown mechanisms occurs in many tumors. Thus, increased levels of MDM2 would inactivate the apoptotic and cell cycle arrest functions of p53, as do deletion or mutation of p53, common events in the genesis of many kinds of tumors. MDM2 functions as an E3 ubiquitin ligase to degrade p53. MDM2 also binds another tumor suppressor, ARF. This interaction sequesters MDM2 in the nucleolus away from p53, thus activating p53. Many additional MDM2 interacting proteins have been identified. Functions of MDM2 independent of p53 have also been identified. This article is an introduction to MDM2, its structure and biological functions, as well as its relationship to its binding partners.     

Plastocyanin,an electron-transfer protein

Plastocyanin (Pc) is a copper (Cu)-containing blue protein, that functions as a mobile electron carrier between cytochrome (cyt) f and Photosystem 1 (PS1) in oxygenic organisms. The atomic structure is known and can be described as a -barrel with hydrophobic residues in the interior of the protein. To increase the understanding about structure-function relationships, site-directed mutagenesis of Pc has proven to be very useful. Mainly two spectroscopic techniques, optical and EPR spectroscopy, have been used to investigate how the copper-site is affected by different mutations. The redox properties of the mutants have been investigated and factors that affect the reduction potential are discussed. Absorption and EPR spectra and reduction potentials for the surface mutants are similar to those of the corresponding wild-type. However, mutants around the Cu ion affected the mentioned properties. Comparisons are made with other cupredoxins. Five site-directed mutants of spinach Pc, Pc(Leu12His), Pc(Leu15His), Pc(Thr79His), Pc(Lys81His) and Pc(Tyr83His), have been modified by covalent attachment of a photoactive ruthenium (Ru)-complex at the surface-exposed histidine residues. The rates of the internal electron-transfer reactions exhibit an exponential dependence on the metal-to-metal separation with a decay factor of 1.1 A_-1. A reorganization energy for the Cu-to-Ru electron-transfer reaction of 1.2 eV was determined. Interprotein electron-transfer reactions involving genetically modified Pc are described. Ionic-strength and pH dependencies indicated that electrostatic interactions are involved in the complex formation between Pc and PS 1, which was confirmed by mutations in the acidic patches of Pc. A very specific interaction was further verified by replacements of hydrophobic residues. Position 10, 12, 36, 87 and 90 were found to be very important for the formation of an active complex. A comparison between available structures of Pc and cyt c₆, both effective donors to PS 1, is made. The physiological electron donor to Pc, cyt f, is briefly described.     

Adiponectin, an adipocyte-derived protein

Adipose tissue is a hormonally active tissue, producing adipocytokines which may influence activity of other tissues. Adiponectin, abundantly present in the plasma increases insulin sensitivity by stimulating fatty acid oxidation, decreases plasma triglycerides and improves glucose metabolism. Adiponectin levels are inversely related to the degree of adiposity. Anorexia nervosa and type 1 diabetes are associated with increased plasma adiponectin levels and higher insulin sensitivity. Decreased plasma adiponectin levels were reported in insulin-resistant states, such as obesity and type 2 diabetes and in patients with coronary artery disease. Activity of adiponectin is associated with leptin, resistin and with steroid and thyroid hormones, glucocorticoids, NO and others. Adiponectin suppresses expression of extracellular matrix adhesive proteins in endothelial cells and atherosclerosis potentiating cytokines. Anti-atherogenic and anti-inflammatory properties of adiponectin and the ability to stimulate insulin sensitivity have made adiponectin an important object for physiological and pathophysiological studies with the aim of potential therapeutic applications.     

City Visualscapes,an Introduction

Socio-anthropological studies on the city have addressed directly the audiovisual recently. This trend emerges from the awareness that the textual materials usually employed in research too often show their limits, given the complexity of the urban phenomena. The increasing use of audiovisual research raises a crucial question: what is the added value of photography and video, as well as of the many extra textual languages that increasingly are complicating research work? The simple diffusion of electronic text and the use of devices have taught us to manipulate text and images simultaneously, but in the process have changed the methodological approach of social sciences from the definition of questions and research hypotheses to the construction of the empirical basis, and finally the writing and analysis, seen as experimental practices that flow into what we might call an expanded search. Urban studies, having complexity as their main object as well as an undeniable encounter of paradigms and disciplines, have implicitly encouraged and made common the use and testing of audiovisual technology. City Visualscapes is an attempt to focus on those experiences of urban research that privilege languages employing experimental visual practices alongside more traditional research tools.     

Nachruf an Christian Ludwig Brehm, an dessen Todestage.

Ohne ZusammenfassungZu dem Friedhof dieses Dorfes, mild umwallt von Sommerlüften, Hat's mich liebend hingezogen. Trauernd blick' ich nach den Grüften. Leuchte mir, du stiller Abend, mit dem heil'gen Purpurfeuer! Einen such' ich, einen Todten, einen, mir vor Vielen theuer! Fächle, Lebensodem, fächle schönen Herzen lang und labend! Ach, uns allen, oft zu frühe, kommt heran eine letzter Abend. Mit den Todten gern noch spräche Liebe dann und öder Kummer; Doch sie liegen tief gebettet, doch sie liegen tief im Schlummer. Auch mit diesem edlen Schläfer tauscht' ich gern noch frohe Worte; Fest verschlossen ist mir aber seine dunkle Grabespforte. Hier, wo, wie mit Geisterflügeln, mich umschwebt die Nachtphaläne, Böt' ich gern ihm meine Rechte, zeigt' ich gern ihm meine Thräne! War ich doch ihm Freund geworden, standen doch bei Vogelchören Unsre Wiegen nah einander^**) neben immer grünen Föhren. Hatten doch die glüh'nde Liebe zur Natur wir eingesogen, Wo mit prächt'gen Wäldern pranget Thüringens Gebirgesbogen. Freunde, nah't denn mit mir heute seiner Gruft, vom Ruhm beleuchtet, Nah't im Geiste, wird euch wieder auch die Wange still befeuchtet! Doch ihr wart schon heut am Grabe, nicht gemahnt durch meine Töne, Liebevolle, treue Gattin, liebevolle, treue Söhne! Aber für die And'ren alle, für die Fremden und für Jeden, Welcher seiner gern gedenket, mögen Lied und Klage reden: Von dem wissensreichen Forscher, von dem Priester am Altare, Von dem Mann, der für das Heil'ge lebte, für das Ewigwahre! Die gekannt ihn, sollen zeugen, wären's selbst auch bittre Feinde, Dass als Vater ihn verehrte, seine fromme Kirchgemeinde. Ja, das Gut, das er genommen mit in's bess're Land hinüber, Seine reine Gottesliebe, trug er auf die Menschen über. Bleibet seines Lobs Verkünder, seiner euch geweihten Liebe Würdig, sucht ihn, all' ihr Vögel, mit dem mächt'gen Reisetriebe! Horcht jedoch dann, während Frühgold weit die wache Welt verschönet, Ob's vielleicht aus seinem Grabe, wie vom Memnonsbilde, tönet. Doch, Natur, dein edler Priester, ganz für deinen Dienst geboren, Ach, er selbst verschwand auf immer! Ach, wir haben ihn verloren! Und von deinen letzten hohen Forschern mit des Ruhmes Laube Ging dahin auch Der, o Deutschland, sank dahin auch Der zum Staube! Aber nicht der Tod vertilgte seines Waltens Spur und Segen; Seine reichen Geistesfrüchte zeugen fort auf hundert Wegen. Sein geliebtes Bild im Herzen lebt auch in der Tugendschöne, Freunde! lebt dir, edle Gattin, lebt euch künftig, treue Söhne! Ist er auch hinweggetragen schweigend unter die Cypressen: In der Wissenschaften Tempel glänzt er, künftig unvergessen. Seiner dankbar auch gedenket, weil er nah ihr ist geboren, Thüringens Gebirgeswaldung mit den hundert Felsenthoren. Und so schlafe vielgesegnet, edler Freund, von Nacht umwoben~ Kannst du noch uns unten hören, oder als Verklärter droben?... Schlafe wohl, von Gott belohnet! Räthsel, hier so schwer und dunkel, Sind gelöst nun deinem Geiste dort im ew'gen Lichtgefunkel! Meine Hand darauf! Du kanntest nicht umsonst der Wesen Stufe Und die Harmonie des Weltalls und die tausend Gottesrufe!—Deine Lieben siehst du wieder, welche nahm des Himmels Ferne: Wieder kommen wir zusammen droben in dem Reich der Sterne! Ph. H. Welcker.Der Abdruck dieses Gedichtes hat sich leider wegen unvorhergesehener Umstände verspätet.Brehm wurde geboren in dem Dorfe Schönau am Walde, das kaum eine Stunde von Georgenthal, dem Geburtsort des Verfassers, entfernt ist.     

Production of glomus intraradices propagules, an arbuscular mycorrhizal fungus, in an airlift bioreactor

This work addresses the symbiotic culture of the arbuscular mycorrhizal (AM) fungus Glomus intraradices with Daucus carota hairy roots transformed by Agrobacterium rhizogenes, in two submerged culture systems: Petri dish and airlift bioreactor. AM fungi play an active role in plant nutrition and protection against plant pathogens. These fungi are obligate biotrophs as they depend on a host plant for their needs in carbohydrates. The effect of the mycorrhizal roots inoculum-to-medium volume ratio on the growth of both symbionts was studied. A critical inoculating condition was observed at approximately 0.6 g dry biomass (DW). L-1 medium, above which root growth was significantly reduced when using a low-salt minimal (M) liquid medium previously developed for hairy root-AM fungi co-culture. Below critical inoculum conditions the maximum specific root growth and specific G. intraradices spore production rates of 0.021 and 0.035 d-1, respectively, were observed for Petri dish cultures. Maximum spore production in the airlift bioreactor was ten times lower than that of Petri dish cultures and obtained with the lowest inoculum assessed (0.13 g DW. L-1 medium) with 1.82 x 10(5) +/- 4.05 x 10(4) (SEM) spores (g DW inoculum)-1 (L medium)-1 in 107 d. This work proposes a second-generation bioprocess for AM fungi propagule production in bioreactors. Copyright 1999 John Wiley & Sons, Inc.     

Targeting of an A kinase-anchoring protein, AKAP79, to an inwardly rectifying potassium channel, Kir2.1

Protein kinase A (PKA) is targeted to discrete subcellular locations close to its intended substrates through interaction with A kinase-anchoring proteins (AKAPs). Ion channels represent a diverse and important group of kinase substrates, and it has been shown that membrane targeting of PKA through association with AKAPs facilitates PKA-mediated phosphorylation and regulation of several classes of ion channel. Here, we investigate the effect of AKAP79, a membrane-associated multivalent-anchoring protein, upon the function and modulation of the strong inwardly rectifying potassium channel, Kir2.1. Functionally, the presence of AKAP79 enhanced the response of Kir2.1 to elevated intracellular cAMP, suggesting a requirement for a pool of PKA anchored close to the channel. Antibodies directed against a hemagglutinin epitope tag on Kir2.1 coimmunoprecipitated AKAP79, indicating that the two proteins exist together in a complex within intact cells. In support of this, glutathione S-transferase fusion proteins of both the intracellular N and C domains of Kir2.1 isolated AKAP79 from cell lysates, while glutathione S-transferase alone failed to interact with AKAP79. Together, these findings suggest that AKAP79 associates directly with the Kir2.1 ion channel and may serve to anchor kinase enzymes in close proximity to key channel phosphorylation sites.