julilili42/papers huggingface dataset:
Three‐dimensional slice cultures from murine fetal gut for investigations of the enteric nervous system
2006-08-07

Abstract Three‐dimensional intestinal cultures offer new possibilities for the examination of growth potential, analysis of time specific gene expression, and spatial cellular arrangement of enteric nervous system in an organotypical environment. We present an easy to produce in vitro model of the enteric nervous system for analysis and manipulation of cellular differentiation processes. Slice cultures of murine fetal colon were cultured on membrane inserts for up to 2 weeks without loss of autonomous contractility. After slice preparation, cultured tissue reorganized within the first days in vitro. Afterward, the culture possessed more than 35 cell layers, including high prismatic epithelial cells, smooth muscle cells, glial cells, and neurons analyzed by immunohistochemistry. The contraction frequency of intestinal slice culture could be modulated by the neurotransmitter serotonin and the sodium channel blocker tetrodotoxin. Coculture experiments with cultured neurospheres isolated from enhanced green fluorescent protein (eGFP) transgenic mice demonstrated that differentiating eGFP‐positive neurons were integrated into the intestinal tissue culture. This slice culture model of enteric nervous system proved to be useful for studying cell–cell interactions, cellular signaling, and cell differentiation processes in a three‐dimensional cell arrangement. Developmental Dynamics 236:128–133, 2007. © 2006 Wiley‐Liss, Inc.
Ethylene‐induced stomatal closure in Arabidopsis occurs via AtrbohF‐mediated hydrogen peroxide synthesis
2006-08-08

Summary Ethylene is a plant hormone that regulates many aspects of growth and development. Despite the well‐known association between ethylene and stress signalling, its effects on stomatal movements are largely unexplored. Here, genetic and physiological data are provided that position ethylene into the Arabidopsis guard cell signalling network, and demonstrate a functional link between ethylene and hydrogen peroxide (H 2 O 2 ). In wild‐type leaves, ethylene induces stomatal closure that is dependent on H 2 O 2 production in guard cells, generated by the nicotinamide adenine dinucleotide phosphate hydrogen (NADPH) oxidase AtrbohF. Ethylene‐induced closure is inhibited by the ethylene antagonists 1‐MCP and silver. The ethylene receptor mutants etr1–1 and etr1–3 are insensitive to ethylene in terms of stomatal closure and H 2 O 2 production. Stomata of the ethylene signalling ein2–1 and arr2 mutants do not close in response to either ethylene or H 2 O 2 but do generate H 2 O 2 following ethylene challenge. Thus, the data indicate that ethylene and H 2 O 2 signalling in guard cells are mediated by ETR1 via EIN2 and ARR2‐dependent pathway(s), and identify AtrbohF as a key mediator of stomatal responses to ethylene.
Degeneration of ingestion‐related brainstem nuclei in spinocerebellar ataxia type 2, 3, 6 and 7
2006-08-08

Dysphagia, which can lead to nutritional deficiencies, weight loss and dehydration, represents a risk factor for aspiration pneumonia. Although clinical studies have reported the occurrence of dysphagia in patients with spinocerebellar ataxia type 2 (SCA2), type 3 (SCA3), type 6 (SCA6) and type 7 (SCA7), there are neither detailed clinical records concerning the kind of ingestive malfunctions which contribute to dysphagia nor systematic pathoanatomical studies of brainstem regions involved in the ingestive process. In the present study we performed a systematic post mortem study on thick serial tissue sections through the ingestion‐related brainstem nuclei of 12 dysphagic patients who suffered from clinically diagnosed and genetically confirmed spinocerebellar ataxias assigned to the CAG‐repeat or polyglutamine diseases (two SCA2, seven SCA3, one SCA6 and two SCA7 patients) and evaluated their medical records. Upon pathoanatomical examination in all of the SCA2, SCA3, SCA6 and SCA7 patients, a widespread neurodegeneration of the brainstem nuclei involved in the ingestive process was found. The clinical records revealed that all of the SCA patients were diagnosed with progressive dysphagia and showed dysfunctions detrimental to the preparatory phase of the ingestive process, as well as the lingual, pharyngeal and oesophageal phases of swallowing. The vast majority of the SCA patients suffered from aspiration pneumonia, which was the most frequent cause of death in our sample. The findings of the present study suggest (i) that dysphagia in SCA2, SCA3, SCA6 and SCA7 patients may be associated with widespread neurodegeneration of ingestion‐related brainstem nuclei; (ii) that dysphagic SCA2, SCA3, SCA6 and SCA7 patients may suffer from dysfunctions detrimental to all phases of the ingestive process; and (iii) that rehabilitative swallow therapy which takes specific functional consequences of the underlying brainstem lesions into account might be helpful in preventing aspiration pneumonia, weight loss and dehydration in SCA2, SCA3, SCA6 and SCA7 patients.
Renal Magnetic Resonance Angiography at 3.0 Tesla Using a 32-Element Phased-Array Coil System and Parallel Imaging in 2 Directions
2006-08-08

MRA at 3.0 T using a 32-element phased-array coil is feasible in healthy volunteers. High diagnostic image quality and extended anatomic coverage could be achieved with application of high parallel imaging factors.
Co‐immobilization of different enzyme activities to non‐woven polyester surfaces
2006-08-08

Abstract Co‐immobilization was applied to combine complementary enzyme reactions. Therefore, trypsin was co‐immobilized together with both, lipase and α‐amylase, onto the surface of non‐woven polyester material. The progress of the immobilization reaction was directly monitored by investigating covalent fixation of the enzymes to the polyester flees using 1 H‐MAS‐NMR. Co‐immobilization of the different types of enzymes to the polyester support showed retained enzymatic activity. However, a competition of binding to the support was observed. Increasing amounts of one type of enzyme reduced the degree of immobilization for the other type. In order to investigate the distribution of trypsin and α‐amylase on the polyester support, the flees was treated with a mixture of rhodamine isothiocyanate labeled with anti‐trypsin antibodies and fluorescein isothiocyanate labeled with anti‐α‐amylase antibodies. Using fluorescence microscopy, the co‐immobilization was analyzed by selective excitation of both chromophores at 480 and 530 nm, respectively. In addition, fluorescence spectroscopy was applied by direct labeling of trypsin and lipase prior to co‐immobilization to the polyester support. A special prism of plexiglass was constructed, which fit into a 10 × 10 mm fluorescence cuvette in that way that a diagonal plane was formed within the cuvette. The non‐woven support was fixed in the cuvette and fluorescence spectra were obtained to characterize the amount of different enzymes linked to the support. Using FRET it was demonstrated that a uniform distribution of the various enzyme species was achieved, where the different enzyme activities are bound on the support in close neighborhood to one another. Biotechnol. Bioeng. 2007;96:623–630. © 2006 Wiley Periodicals, Inc.
FO[\\le]-Uniformity
2006-08-08

Uniformity notions more restrictive than the usual FO[<, +, *]-uniformity = FO[<, Bit]-uniformity are introduced. It is shown that the general framework exhibited by Barrington et al. still holds if the fan-in of the gates in the corresponding circuits is considered.
Differential microglial regulation in the human spinal cord under normal and pathological conditions
2006-08-08

As the primary intrinsic immune effector cells of the central nervous system, microglia are involved in virtually all pathological processes of the brain and spinal cord including inflammatory, neurodegenerative, traumatic, neoplastic and vascular diseases. Despite this important role, there is a lack of data concerning microglial distribution and protein expression in the human spinal cord. In this study, we immunohistochemically investigated 10 normal human spinal cords to establish reference data and compared these results with 15 pathological human spinal cords deriving from distinct pathologies. Each spinal cord was evaluated at eight different levels for three white and two grey matter areas for both constitutive (MHC‐II, CD68, IL‐16, AIF‐1, LCA, CD4) and reactive (MRP‐8, MRP‐14) microglial antigens. Whereas previous studies revealed significant regional differences in microglial distribution and protein expression in human brain, normal spinal cord displayed a uniform expression pattern, reaching levels of up to 17% MHC‐II positive cells of the total cell population. This datum formed the basis for the further evaluation of microglia expression levels in pathological spinal cords, where levels of up to 45% positive cells were observed. Our results represent important reference values for future neuropathological diagnostic and therapeutical approaches in spinal cord pathologies.
Constituents of Hybrid Reality: Cultural Anthropological Reflections and a Serious Game Design Experiment Merging Mobility, Media and Computing
2006-08-08

We are currently encountering a "hybrid reality" in which mobility, media and computing are merging. As a result, our socio-emotional interactions and ways of communicating are changing dramatically, along with ubiquitous technological devices and environments. This change can be reflected in and researched through experimental game design and cultural anthropological analysis. Part I of this paper gives a detailed theoretical outline, and part II introduces M.A.D. COUNTDOWN, a mobile multiplayer prototype game that investigates and facilitates proximate distance and distant proximity on the move into hybrid reality.
Expression of platelet collagen receptor glycoprotein VI is associated with acute coronary syndrome
2006-08-09

Platelet GPVI surface expression is elevated in patients with ACS and is associated with imminent acute coronary events. The determination of the platelet-specific thrombotic marker GPVI may help to identify patients at risk before myocardial ischaemia is evident.
Native and subunit molecular mass and quarternary structure of the hemoglobin from the primitive branchiopod crustacean Triops cancriformis
2006-08-09

Many branchiopod crustaceans are endowed with extracellular, high‐molecular‐weight hemoglobins whose exact structural characteristics have remained a matter of conjecture. By using a broad spectrum of techniques, we provide precise and coherent information on the hemoglobin of one of the phylogenetically ‘oldest’ extant branchiopods, the tadpole shrimp Triops cancriformis . The hemoglobin dissociated under reducing conditions into two subunits, designated TcHbA and TcHbB, with masses of 35 775 ± 4 and 36 055 ± 4 Da, respectively, determined by ESI‐MS. Nonreducing conditions showed only two disulfide‐bridged dimers, a homodimer of TcHbA, designated D1 (71 548 ± 5 Da), and the heterodimer D2 (71 828 ± 5 Da). Carbamidomethylation of free SH groups revealed the presence of three cysteines per subunit and indicated one intrasubunit and one intersubunit disulfide bridge. Ultracentrifugation and light‐scattering experiments under nondenaturating conditions yielded mass estimates that suggested an uneven number of 17 subunits forming the native hemoglobin. This unrealistic number resulted from the presence of two size classes (16‐mer and 18‐mer), which were recognized by native PAGE and Ferguson plot analysis. ESI‐MS revealed three hemoglobin isoforms with masses of 588.1 kDa, 662.0 kDa, and 665.0 kDa. The 16‐mer and the smaller 18‐mer species are supposed to be composed of TcHbA only, given the dominance of this subunit type in SDS/PAGE. Transmission electron microscopy of negatively stained specimens showed a population of compact molecules with geometrical extensions of 14, 16 and 9 nm. The proposed stoichiometric model of quarternary structure provides the missing link to achieve a mechanistic understanding of the structure–function relationships among the multimeric arthropodan hemoglobins.
4-[3-(4-Fluorophenyl)-5-isopropylisoxazol-4-yl]pyridine
2006-08-09

The molecular structure of the title compound, C17H15FN2O, was determined in the course of our studies on mitogen-activated protein kinase inhibitors. The exocyclic bond angles at the carbon atoms of the isoxazole ring bearing the pyridyl and 4-fluorophenyl rings are 130.0 (2) and 129.2 (2)°, respectively. The pyridine and 4-fluorophenyl rings are twisted relative to the isoxazole ring by 80.2 (2) and 19.1 (1)°, respectively.
Synthesis of Luminacin D
2006-08-10

The total synthesis of luminacin D (1) is reported on the basis of two aldol reactions to form the carbohydrate sector, aldehyde 30. Reaction of aldehyde 30 with the aryllithium intermediate derived from aryl iodide 38, cleavage of the silyl ether, and oxidation led to keto aldehyde 41. This advanced intermediate could be converted to luminacin 1 and its 6',8'-epimer.
Phosphoenolpyruvate carboxylase genes in C3, crassulacean acid metabolism (CAM) and C3/CAM intermediate species of the genus Clusia: rapid reversible C3/CAM switches are based on the C3 housekeeping gene
2006-08-10

ABSTRACT The genus Clusia includes species that exhibit either the C 3 or crassulacean acid metabolism (CAM) mode of photosynthesis, or those that are able to switch between both modes according to water availability. In order to screen for species‐specific genetic variability, we investigated the key carboxylase for CAM, phospho enol pyruvate carboxylase (PEPC). Sequence analysis of DNA isolated from the obligate CAM species, Clusia hilariana , the obligate C 3 species, Clusia multiflora , and an intermediate species that can switch between C 3 and CAM photosynthesis, Clusia minor , revealed three different isoforms for C. hilariana and one each for the other two species. Sequence alignments indicated that PEPC from the intermediate species had high homology with the C 3 protein and with one of CAM plant proteins. These were assumed to constitute ‘housekeeping’ proteins, which can also support CAM in intermediate species. The other two isoforms of the CAM plant C. hilariana were either CAM‐specific or showed homologies with PEPC from roots. Phylogenetic trees derived from neighbour‐joining analysis of amino acid sequences from 13 different Clusia species resulted in two distinct groups of plants with either ‘housekeeping’ PEPC only, or additionally CAM‐related isoforms. Only C. hilariana showed the third, probably root‐specific isoform. The high homology of the PEPC from the intermediate species with the C 3 protein indicates that for the reversible transition from the C 3 to CAM mode of photosynthesis, the C 3 type of PEPC is sufficient. Its expression, however, is strongly increased under CAM‐inducing conditions. The use of the C 3 isoform could have facilitated the evolution of CAM within the genus, which occurred independently for several times.
Herpes virus entry mediator synergizes with Toll‐like receptor mediated neutrophil inflammatory responses
2006-08-10

Summary In microbial infections polymorphnuclear neutrophils (PMN) constitute a major part of the innate host defence, based upon their ability to rapidly accumulate in inflamed tissues and clear the site of infection from microbial pathogens by their potent effector mechanisms. The recently described transmembrane receptor herpes virus entry mediator (HVEM) is a member of the tumour necrosis factor receptor super family and is expressed on many haematopoietic cells, including T cells, B cells, natural killer cells, monocytes and PMN. Interaction of HVEM with the natural ligand LIGHT on T cells has a costimulatory effect, and increases the bactericidal activity of PMN. To further characterize the function of HVEM on PMN, we evaluated the effect of receptor ligation on human PMN effector functions using an agonistic monoclonal antibody. Here we demonstrate that activation of HVEM causes activation of neutrophil effector functions, including respiratory burst, degranulation and release of interleukin‐8 in synergy with ligands for Toll‐like receptors or GM‐CSF. In addition, stimulation via HVEM enhanced neutrophil phagocytic activity of complement opsonized, but not of non‐opsonized, particles. In conclusion, these results indicate a new, as yet unknown, participation of HVEM in the innate immune response and points to a new link between innate and adaptive immunity.
Deafness in LIMP2‐deficient mice due to early loss of the potassium channel KCNQ1/KCNE1 in marginal cells of the stria vascularis
2006-08-11

Our previous studies revealed a critical role of the lysosomal membrane protein LIMP2 in the regulation of membrane transport processes in the endocytic pathway. Here we show that LIMP2‐deficient mice display a progressive high‐frequency hearing loss and decreased otoacoustic emissions as early as 4 weeks of age. In temporal overlap to hearing impairment, fluorescence immunohistochemical studies revealed that the potassium channel KCNQ1 and its β‐subunit KCNE1 were almost completely lost in the luminal part of marginal cells in the stria vascularis, affecting first higher and later also lower frequency processing cochlear turns. Concomitant with this, the expression of megalin, a multiligand endocytic receptor, was reduced in luminal surfaces of marginal cells within the stria vascularis. KCNQ1/KCNE1 and megalin were also lost in the dark cells of the vestibular system. Although LIMP2 is normally expressed in all cells of the stria vascularis, in the organ of Corti and cochlear neurons, the lack of LIMP2 preferentially caused a loss of KCNQ1/KCNE1 and megalin, and structural changes were only seen months later, indicating that these proteins are highly sensitive to disturbances in the lysosomal pathway. The spatio‐temporal correlation of the loss of KCNQ1/KCNE1 surface expression and loss of hearing thresholds supports the notion that the decline of functional KCNQ1/KCNE1 is likely to be the primary cause of the hearing loss. Our findings suggest an important role for LIMP2 in the control of the localization and the level of apically expressed membrane proteins such as KCNQ1, KCNE1 and megalin in the stria vascularis.
Orientation of Differently Substituted Phthalocyanines: First Layers and Thin Films
2006-08-15

The molecular orientation of the first layers and thin films of differently substituted phthalocyanines on gold substrates is compared. Due to a relatively strong molecule-substrate interaction the orientation is parallel to the sample surface for all materials in the first layers. At higher film thickness the orientation is determined by the substituents. Materials with short substituents prefer standing orientation, implying the substituents do not inhibit the intermolecular interactions. Molecules with long substituents are not able to build up the same aggregates, they grow disordered in the upper layers.
Chemical Synthesis of a Glycolipid Library by a Solid‐Phase Strategy Allows Elucidation of the Structural Specificity of Immunostimulation by Rhamnolipids
2006-08-17

Abstract The first synthesis of a glycolipid library by hydrophobically assisted switching phase (HASP) synthesis is described. HASP synthesis enables flexible switching between solution‐phase steps and solid‐supported reactions conducted with molecules attached to a hydrophobic silica support. A library of glycolipids derived from the lead compound 1 —a strongly immunostimulatory rhamnolipid—with variations in the carbohydrate part, the lipid components, and the stereochemistry of the 3‐hydroxy fatty acids was designed and synthesized. The enantioselective synthesis of the 3‐hydroxy fatty acid building blocks was achieved by employing asymmetric hydrogenation of 3‐oxo fatty acids. Glycolipids were prepared by this approach without any intermediary isolation steps, mostly in excellent yields. Final deprotection to the carboxylic acids was accomplished by enzymatic ester cleavage. All prepared rhamnolipids were tested for their immunostimulatory properties against human monocyte cells by assaying the secretion of the cytokine tumor necrosis factor α (TNFα) into the medium. The observed structure–activity relationships of rhamnolipids indicate a specific, recognition‐based mode of action, with small structural variations in the rhamnolipids resulting in strong effects on the immunostimulatory activities of the rhamnolipids at low micromolar concentrations.
Enzyme‐Catalyzed Sulfide Ring Formation in Lantibiotics
2006-08-17

Building bridges: The crystal structure of the zinc enzyme NisC was solved recently by X-ray diffraction. This cyclase single-handedly catalyzes the formation of several sulfide bridges in the dehydrated precursor protein NisA of the lantibiotic nisin. The Highlight discusses the impact of these results on the field of lantibiotic research.
Secondary syphilis after liver transplantation: case report and review of the literature
2006-08-18

Abstract: Syphilitic disease is uncommon, but its incidence has increased worldwide in the last few years. An unusual manifestation of secondary syphilis after orthotopic liver transplantation is described which confirms that lues should be considered in patients with immune deficiency and abnormal liver function tests.
Fatty acid regulation of adenylyl cyclase Rv2212 from Mycobacterium tuberculosis H37Rv
2006-08-21

Adenylyl cyclase Rv2212 from Mycobacterium tuberculosis has a domain composition identical to the pH‐sensing isoform Rv1264, an N‐terminal regulatory domain and a C‐terminal catalytic domain. The maximal velocity of Rv2212 was the highest of all 10 mycobacterial cyclases investigated to date (3.9 μmol cAMP·mg −1 ·min −1 ), whereas ATP substrate affinity was low (SC 50 = 2.1 m m ATP). Guanylyl cyclase side activity was absent. The activities and kinetics of the holoenzyme and of the catalytic domain alone were similar, i.e. in distinct contrast to the Rv1264 adenylyl cyclase, in which the N‐terminal domain is autoinhibitory. Unsaturated fatty acids strongly stimulated Rv2212 activity by increasing substrate affinity. In addition, fatty acids greatly enhanced the pH sensitivity of the holoenzyme, thus converting Rv2212 to a pH sensor adenylyl cyclase. Fatty acid binding to Rv2212 was modelled by homology to a recent structure of the N‐terminal domain of Rv1264, in which a fatty acid‐binding pocket is defined. Rv2212 appears to integrate three cellular parameters: ATP concentration, presence of unsaturated fatty acids, and pH. These regulatory properties open the possibility that novel modes of cAMP‐mediated signal transduction exist in the pathogen.
An interpretive effect of head movement
2006-08-21

Grohmann, Idan Landau, Howard Lasnik, Roland Hinterholzl, Henk vanRiemsdijk, Wolfgang Sternefeld, Uli Sauerland and in particular Orin Percus for discussion, and the audiences of GACL 1 (Cyprus), Incontro XXXI (Rome), and Glow 2005 (Geneva) for comments. Kyle Johnson, Chris Kennedy, Jason Merchant and Orin Percus kindly provided judgements. A long version of this paper circulates as Lechner (2005a).
Residues Involved in FecR Binding Are Localized on One Side of the FecA Signaling Domain in Escherichia coli
2006-08-21

ABSTRACT Ferric citrate transport in Escherichia coli involves proteins encoded by the fec genes, including the transport and signaling protein FecA and the signal transducing protein FecR. Randomly isolated FecA point mutants showed a reduced interaction with FecR and a reduced transcription initiation of the ferric citrate transport genes. The mutations were localized on one side of the FecA signaling domain, which might form the interface to FecR. Some of the mutants showed strongly reduced iron transport rates, which suggests that the signaling domain affects the structure of the FecA transporter domain.