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First Insights (first + insight)
Selected AbstractsSeeking long-term relationship: axon and target communicate to organize synaptic differentiationJOURNAL OF NEUROCHEMISTRY, Issue 5 2006Michael A. Fox Abstract Synapses form after growing axons recognize their appropriate targets. The subsequent assembly of aligned pre and postsynaptic specializations is critical for synaptic function. This highly precise apposition of presynaptic elements (i.e. active zones) to postsynaptic specializations (i.e. neurotransmitter receptor clusters) strongly suggests that communication between the axon and target is required for synaptic differentiation. What trans-synaptic factors drive such differentiation at vertebrate synapses? First insights into the answers to this question came from studies at the neuromuscular junction (NMJ), where axon-derived agrin and muscle-derived laminin ,2 induce post and presynaptic differentiation, respectively. Recent work has suggested that axon- and target-derived factors similarly drive synaptic differentiation at central synapses. Specifically, WNT-7a, neuroligin, synaptic cell adhesion molecule (SynCAM) and fibroblast growth factor-22 (FGF-22) have all been identified as target-derived presynaptic organizers, whereas axon-derived neuronal activity regulated pentraxin (Narp), ephrinB and neurexin reciprocally co-ordinate postsynaptic differentiation. In addition to these axon- and target-derived inducers of synaptic differentiation, factors released from glial cells have also been implicated in regulating synapse assembly. Together, these recent findings have profoundly advanced our understanding of how precise appositions are established during vertebrate nervous system development. [source] Human skin: source of and target organ for angiotensin IIEXPERIMENTAL DERMATOLOGY, Issue 3 2004U. Muscha Steckelings Abstract:, The present study examined the expression of angiotensin receptors in human skin, the potential synthesis of angiotensin II (Ang II) in this location and looked for a first insight into physiological functions. AT1 and AT2 receptors were found within the epidermis and in dermal vessel walls. The same expression pattern was found for angiotensinogen, renin and angiotensin-converting enzyme (ACE). All components could additionally be demonstrated at mRNA level in cultured primary keratinocytes, melanocytes, dermal fibroblasts and dermal microvascular endothelial cells, except for AT2 receptors in melanocytes. The ability of cutaneous cells to synthesize Ang II was proved by identifying the molecule in cultured keratinocytes. Furthermore, in artificially wounded keratinocyte monolayers, ACE-mRNA expression was rapidly increased, and enhanced ACE expression was still found in cutaneous human scars 3 months after wounding. These findings suggest that the complete renin,angiotensin system is present in human skin and plays a role in normal cutaneous homeostasis as well as in human cutaneous wound healing. [source] Links between methane flux and transcriptional activities of methanogens and methane oxidizers in a blanket peat bogFEMS MICROBIOLOGY ECOLOGY, Issue 1 2010Thomas E. Freitag Abstract The relationship between biogeochemical process rates and microbial functional activity was investigated by analysis of the transcriptional dynamics of the key functional genes for methanogenesis (methyl coenzyme M reductase; mcrA) and methane oxidation (particulate methane monooxygenase; pmoA) and in situ methane flux at two peat soil field sites with contrasting net methane-emitting and -oxidizing characteristics. qPCR was used to quantify the abundances of mcrA and pmoA genes and transcripts at two soil depths. Total methanogen and methanotroph transcriptional dynamics, calculated from mcrA and pmoA gene : transcript abundance ratios, were similar at both sites and depths. However, a linear relationship was demonstrated between surface mcrA and pmoA transcript dynamics and surface flux rates at the methane-emitting and methane-oxidizing sites, respectively. Results indicate that methanotroph activity was at least partially substrate-limited at the methane-emitting site and by other factors at the methane-oxidizing site. Soil depth also contributed to the control of surface methane fluxes, but to a lesser extent. Small differences in the soil water content may have contributed to differences in methanogen and methanotroph activities. This study therefore provides a first insight into the regulation of in situ, field-level surface CH4 flux at the molecular level by an accurate reflection of gene : transcript abundance ratios for the key genes in methane generation and consumption. [source] Identification of phosphatidylserine decarboxylases 1 and 2 from Pichia pastorisFEMS YEAST RESEARCH, Issue 6 2009Tamara Wriessnegger Abstract Genetic manipulation of lipid biosynthetic enzymes allows modification of cellular membranes. We made use of this strategy and constructed mutants in phospholipid metabolism of Pichia pastoris, which is widely used in biotechnology for expression of heterologous proteins. Here we describe identification of two P. pastoris phosphatidylserine decarboxylases (PSDs) encoded by genes homologous to PSD1 and PSD2 from Saccharomyces cerevisiae. Using P. pastoris psd1, and psd2, mutants we investigated the contribution of the respective gene products to phosphatidylethanolamine synthesis, membrane composition and cell growth. Deletion of PSD1 caused loss of PSD activity in mitochondria, a severe growth defect on minimal media and depletion of cellular and mitochondrial phosphatidylethanolamine levels. This defect could not be compensated by Psd2p, but by supplementation with ethanolamine, which is the substrate for the cytidine diphosphate (CDP),ethanolamine pathway, the third route of phosphatidylethanolamine synthesis in yeast. Fatty acid analysis showed selectivity of both Psd1p and Psd2p in vivo for the synthesis of unsaturated phosphatidylethanolamine species. Phosphatidylethanolamine species containing palmitic acid (16:0), however, were preferentially assembled into mitochondria. In summary, this study provides first insight into membrane manipulation of P. pastoris, which may serve as a useful method to modify cell biological properties of this microorganism for biotechnological purposes. [source] Evolutionary history of the ancient cutinase family in five filamentous Ascomycetes reveals differential gene duplications and losses and in Magnaporthe grisea shows evidence of sub- and neo-functionalizationNEW PHYTOLOGIST, Issue 3 2008Pari Skamnioti Summary ,,The cuticle is the first barrier for fungi that parasitize plants systematically or opportunistically. Here, the evolutionary history is reported of the multimembered cutinase families of the plant pathogenic Ascomycetes Magnaporthe grisea, Fusarium graminearum and Botrytis cinerea and the saprotrophic Ascomycetes Aspergillus nidulans and Neurospora crassa. ,,Molecular taxonomy of all fungal cutinases demonstrates a clear division into two ancient subfamilies. No evidence was found for lateral gene transfer from prokaryotes. The cutinases in the five Ascomycetes show significant copy number variation, they form six clades and their extreme sequence diversity is highlighted by the lack of consensus intron. The average ratio of gene duplication to loss is 2 : 3, with the exception of M. grisea and N. crassa, which exhibit extreme family expansion and contraction, respectively. ,,Detailed transcript profiling in vivo, categorizes the M. grisea cutinases into four regulatory patterns. Symmetric or asymmetric expression profiles of phylogenetically related cutinase genes suggest subfunctionalization and neofunctionalization, respectively. ,,The cutinase family-size per fungal species is discussed in relation to genome characteristics and lifestyle. The ancestry of the cutinase gene family, together with the expression divergence of its individual members provides a first insight into the drivers for niche differentiation in fungi. [source] A recurrent ITGA9 missense mutation in human fetuses with severe chylothorax: possible correlation with poor response to fetal therapyPRENATAL DIAGNOSIS, Issue 11 2008Gwo-Chin Ma Abstract Objectives To assess the possible correlations between the reported candidate genes (VEGFR3, FOXC2, ITGA9 and ITGB1) and the clinical response in fetuses with severe congenital chylothorax (CC) treated by prenatal OK-432 pleurodesis. Methods We studied 12 unrelated fetuses with severe CC, receiving fetal therapy by OK-432 pleurodesis. Genotyping of the candidate genes and the clinical parameters of these 12 fetuses were investigated. Additional 96 control individuals were enrolled to evaluate the possible polymorphisms at these candidate genes in population. Results A recurrent heterozygous missense mutation (c.1210G > A, p.G404S) was identified in the beta-propeller domain of integrin ,9 (ITGA9), a cell adhesion receptor, in four of the five fetuses who failed to respond to the OK-432 treatment. Computer modeling of the p.G404S substitution supported the deleterious nature of this mutation. Family analyses in three affected fetuses demonstrated that the heterozygous mutant allele is of parental origin, suggesting an autosomal recessive inheritance of this genetic defect. Conclusions To the best of our knowledge, this is the first insight into the possible link between ITGA9 and CC in human fetuses. The identification of pathogenetic mutations and their possible link to the clinical responses of particular treatments may contribute to better pregnancy counseling and management. Copyright © 2008 John Wiley & Sons, Ltd. [source] Structures of the nucleotide-binding domain of the human ABCB6 transporter and its complexes with nucleotidesACTA CRYSTALLOGRAPHICA SECTION D, Issue 9 2010Matthias Haffke The human ATP-binding cassette (ABC) transporter ABCB6 is involved in haem-precursor transport across the mitochondrial membrane. The crystal structure of its nucleotide-binding domain (NBD) has been determined in the apo form and in complexes with ADP, with ADP and Mg2+ and with ATP at high resolution. The overall structure is L-shaped and consists of two lobes, consistent with other reported NBD structures. Nucleotide binding is mediated by the highly conserved Tyr599 and the Walker A motif, and induces notable structural changes. Structural comparison with other structurally characterized NBDs and full-length ABC transporters gives the first insight into the possible catalytic mechanism of ABCB6 and the role of the N-terminal helix ,1 in full-length ABCB6. [source] Monogenic diabetes: information seeking and genetic testing access via e-mailEUROPEAN DIABETES NURSING, Issue 2 2010M Shepherd RGN, PhD Honorary Clinical Senior Lecturer Abstract Background: Confirmation of monogenic diabetes by molecular genetic testing has allowed many patients, often previously assumed to have type 1 diabetes, to transfer from insulin injections to sulphonylurea tablets, with improvements in glycaemic control and quality of life: www.diabetesgenes.org provides information about monogenic diabetes and genetic testing. Aim: To investigate key issues raised by individuals who e-mailed the monogenic diabetes team about genetic testing and monogenic diabetes management. Methods: Sixty e-mail enquiries, received over a six-month period from patients and professionals worldwide, were analysed using a qualitative thematic content approach. Results: Five themes emerged: 1. Accessing genetic technology: patients and professionals both enquired about access to testing; 2. Presentation of evidence: medical facts presented by patients and professionals included characteristics specifically relevant to diagnosing monogenic diabetes; 3. Experiences of healthcare: patients often researched their condition online and some felt dissatisfied with routine consultations; 4. Seeking specialist advice regarding treatment: specific information was sought relating to management of neonatal diabetes or monogenic diabetes and pregnancy; 5. Searching for a cure through genetic technology: patients questioned whether genetic advances would lead to a cure for diabetes. Conclusion: This project offers the first insights into use of e-mail as a means of gaining access to a specialist monogenic team and information about genetic testing. Although providing advice via e-mail can prove complicated, particularly when received from patients under the care of other clinicians, it is an efficient means of communicating specialist knowledge. Study findings will aid development of a ,frequently asked questions' section of www.diabetesgenes.org. Copyright © 2010 FEND [source] Insights into the structure of plant ,-type phospholipase DFEBS JOURNAL, Issue 10 2007Susanne Stumpe Phospholipases D play an important role in the regulation of cellular processes in plants and mammals. Moreover, they are an essential tool in the synthesis of phospholipids and phospholipid analogs. Knowledge of phospholipase D structures, however, is widely restricted to sequence data. The only known tertiary structure of a microbial phospholipase D cannot be generalized to eukaryotic phospholipases D. In this study, the isoenzyme form of phospholipase D from white cabbage (PLD,2), which is the most widely used plant phospholipase D in biocatalytic applications, has been characterized by small-angle X-ray scattering, UV-absorption, CD and fluorescence spectroscopy to yield the first insights into its secondary and tertiary structure. The structural model derived from small-angle X-ray scattering measurements reveals a barrel-shaped monomer with loosely structured tops. The far-UV CD-spectroscopic data indicate the presence of ,-helical as well as ,-structural elements, with the latter being dominant. The fluorescence and near-UV CD spectra point to tight packing of the aromatic residues in the core of the protein. From the near-UV CD signals and activity data as a function of the calcium ion concentration, two binding events characterized by dissociation constants in the ranges of 0.1 mm and 10,20 mm can be confirmed. The stability of PLD,2 proved to be substantially reduced in the presence of calcium ions, with salt-induced aggregation being the main reason for irreversible inactivation. [source] Retrieval of first genome data for rice cluster I methanogens by a combination of cultivation and molecular techniquesFEMS MICROBIOLOGY ECOLOGY, Issue 2 2005Christoph Erkel Abstract We report first insights into a representative genome of rice cluster I (RC-I), a major group of as-yet uncultured methanogens. The starting point of our study was the methanogenic consortium MRE50 that had been stably maintained for 3 years by consecutive transfers to fresh medium and anaerobic incubation at 50 °C. Process-oriented measurements provided evidence for hydrogenotrophic CO2 -reducing methanogenesis. Assessment of the diversity of consortium MRE50 suggested members of the families Thermoanaerobacteriaceae and Clostridiaceae to constitute the major bacterial component, while the archaeal population was represented entirely by RC-I. The RC-I population amounted to more than 50% of total cells, as concluded from fluorescence in situ hybridization using specific probes for either Bacteria or Archaea. The high enrichment status of RC-I prompted construction of a large insert fosmid library from consortium MRE50. Comparative sequence analysis of internal transcribed spacer (ITS) regions revealed that three different RC-I rrn operon variants were present in the fosmid library. Three, approximately 40-kb genomic fragments, each representative for one of the three different rrn operon variants, were recovered and sequenced. Computational analysis of the sequence data resulted in two major findings: (i) consortium MRE50 most likely harbours only a single RC-I genotype, which is characterized by multiple rrn operon copies; (ii) seven genes were identified to possess a strong phylogenetic signal (eIF2a, dnaG, priA, pcrA, gatD, gatE, and a gene encoding a putative RNA-binding protein). Trees exemplarily computed for the deduced amino acid sequences of eIF2a, dnaG, and priA corroborated a specific phylogenetic association of RC-I with the Methanosarcinales. [source] The cell cycle of SulfolobusMOLECULAR MICROBIOLOGY, Issue 3 2007Rolf Bernander Summary Much of the current information about the archaeal cell cycle has been generated through studies of the genus Sulfolobus. The overall organization of the cell cycle in these species is well understood, and information about the regulatory principles that govern cell cycle progression is rapidly accumulating. Exciting progress regarding the control and molecular details of the chromosome replication process is evident, and the first insights into the elusive crenarchaeal mitosis and cytokinesis machineries are within reach. [source] New effects of type III effectorsMOLECULAR MICROBIOLOGY, Issue 2 2003Roger Innes Summary The enzymatic activities and/or targets of four type III effector proteins from plant pathogens have been reported in a flurry of new papers. In this issue, XopD is shown to remove SUMO groups from host cell proteins, while in previous issues of Molecular Microbiology, HopPtoD2 was shown to function as a tyrosine phosphatase and AvrRpt2 as probably a cysteine protease that targets the host RIN4 protein. Finally, AvrPphB is revealed in a recent Science paper to function as a cysteine protease that targets the host PBS1 kinase. This work is providing some of the first insights into how plant pathogens subvert host cell signalling machinery to cause disease. [source] Functional proteomic view of metabolic regulation in "Aromatoleum aromaticum" strain EbN1PROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 13 2007Lars Wöhlbrand Abstract The denitrifying "Aromatoleum aromaticum" strain EbN1 utilizes a wide range of aromatic and nonaromatic compounds under anoxic and oxic conditions. The recently determined genome revealed corresponding degradation pathways and predicted a fine-tuned regulatory network. In this study, differential proteomics (2-D DIGE and MS) was used to define degradation pathway-specific subproteomes and to determine their growth condition dependent regulation. Differential protein profiles were determined for cultures adapted to growth under 22 different substrate and redox conditions. In total, 354 different proteins were identified, 199 of which displayed significantly changed abundances. These regulated proteins mainly represented enzymes of the different degradation pathways, and revealed different degrees of growth condition specific regulation. In case of three substrate conditions (e.g. phenylalanine, anoxic), proteins previously predicted to be involved in their degradation were apparently not involved (e.g. Pdh, phenylacetaldehyde dehydrogenase). Instead, previously not considered proteins were specifically increased in abundance (e.g. EbA5005, predicted aldehyde:ferredoxin oxidoreductase), shedding new light on the respective pathways. Moreover, strong evidence was obtained for thus far unpredicted degradation pathways of three hitherto unknown substrates (e.g. o -aminobenzoate, anoxic). Comparing all identified regulated and nonregulated proteins provided first insights into regulatory hierarchies of special degradation pathways versus general metabolism in strain EbN1. [source] Treatment-dependent Loss of Polyfunctional CD8+ T-cell Responses in HIV-infected Kidney Transplant Recipients Is Associated with Herpesvirus ReactivationAMERICAN JOURNAL OF TRANSPLANTATION, Issue 4 2009O. Gasser Antiretroviral-therapy has dramatically changed the course of HIV infection and HIV-infected (HIV(+)) individuals are becoming more frequently eligible for solid-organ transplantation. However, only scarce data are available on how immunosuppressive (IS) strategies relate to transplantation outcome and immune function. We determined the impact of transplantation and immune-depleting treatment on CD4+ T-cell counts, HIV-, EBV-, and Cytomegalovirus (CMV)-viral loads and virus-specific T-cell immunity in a 1-year prospective cohort of 27 HIV(+) kidney transplant recipients. While the results show an increasing breadth and magnitude of the herpesvirus-specific cytotoxic T-cell (CTL) response over-time, they also revealed a significant depletion of polyfunctional virus-specific CTL in individuals receiving thymoglobulin as a lymphocyte-depleting treatment. The disappearance of polyfunctional CTL was accompanied by virologic EBV-reactivation events, directly linking the absence of specific polyfunctional CTL to viral reactivation. The data provide first insights into the immune-reserve in HIV+ infected transplant recipients and highlight new immunological effects of thymoglobulin treatment. Long-term studies will be needed to assess the clinical risk associated with thymoglobulin treatment, in particular with regards to EBV-associated lymphoproliferative diseases. [source] Autism genetics: strategies, challenges, and opportunitiesAUTISM RESEARCH, Issue 1 2008Brian J. O'Roak Abstract Although genes have long been appreciated to play a critical role in determining the risk for pervasive developmental disorders, the specific transcripts contributing to autism spectrum disorders (ASD) have been quite difficult to characterize. However, recent findings are now providing the first insights into the molecular mechanisms underlying these syndromes and have begun to shed light on the allelic architecture of ASD. In this article, we address what is known about the relative contributions of various types of genetic variation to ASD, consider the obstacles facing gene discovery in this complex disorder, and evaluate the common methodologies employed to address these issues, including linkage, molecular and array-based cytogenetics, and association strategies. We review the current literature, highlighting recent findings implicating both rare mutations and common genetic polymorphisms in the etiology of autism. Finally, we describe key advances in genomic technologies that are transforming all areas of human genetics and consider both the opportunities and challenges for autism research posed by these rapid changes. [source] Structure of O67745_AQUAE, a hypothetical protein from Aquifex aeolicusACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 5 2007Vaheh Oganesyan Using single-wavelength anomalous dispersion data obtained from a gold-derivatized crystal, the X-ray crystal structure of the protein 067745_AQUAE from the prokaryotic organism Aquifex aeolicus has been determined to a resolution of 2.0,Å. Amino-acid residues 1,371 of the 44,kDa protein were identified by Pfam as an HD domain and a member of the metal-dependent phosphohydrolase superfamily (accession No. PF01966). Although three families from this large and diverse group of enzymatic proteins are represented in the PDB, the structure of 067745_AQUAE reveals a unique fold that is unlike the others and that is likely to represent a new subfamily, further organizing the families and characterizing the proteins. Data are presented that provide the first insights into the structural organization of the proteins within this clan and a distal alternative GDP-binding domain outside the metal-binding active site is proposed. [source] Molecular Editing and Biological Evaluation of Amphidinolide X and YCHEMISTRY - A EUROPEAN JOURNAL, Issue 16 2009Alois Fürstner Prof. Abstract Scarce and precious: A collection of compounds with deep-seated structural "point mutations" within the framework of the marine natural products amphidinolide X and Y was prepared by "diverted total synthesis". The resulting products provided first insights into the cytotoxicity profile of these extremely scarce macrolides. Deliberate deviations from the previously described total syntheses of amphidinolide X (1) and Y (2) allowed a collection of seven designed analogues of these extremely scarce marine natural products to be obtained. These fully synthetic "natural product-like" compounds enabled first insights into the previously unknown structure,activity relationships governing this series. Although the average cytotoxicity is moderate, it was found that certain bladder, colon and prostate cancer cell lines are fairly sensitive, and that the best synthetic analogues are more active than the natural products themselves. The syntheses rely on the 9-MeO-9-BBN variant of the Suzuki coupling for the formation of the carbon frameworks, as well as on Yamaguchi lactonization reactions for the cyclization of the macrocyclic rings. [source] | ||||||||||||||||