bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intra‐ and inter‐lake variability of free‐living and particle‐associated Actinobacteria communities
Authors: Allgaier Martin , Brückner Sarah , Jaspers Elke , Grossart Hans‐Peter 
Published: July 2007

SummaryWe have analysed the inter‐ and intra‐lake variability of free‐living and particle‐associated freshwater Actinobacteria communities in four limnological different lakes of the Mecklenburg Lake District, Northeastern Germany. Denaturing gradient gel electrophoresis (DGGE) specific for Actinobacteria was used to investigate phylogenetic diversity and seasonal dynamics of actinobacterial communities in the epilimnion of all lakes (inter‐lake variability) and to assess differences between Actinobacteria communities of the epi‐, meta‐ and hypolimnion of a single lake (intra‐lake variability) respectively. DGGE analyses showed significant inter‐ and intra‐lake differences between Actinobacteria communities of all lakes and water layers as well as between free‐living and particle‐associated Actinobacteria. Phylogenetic inferences of 16S rRNA gene sequences suggest that particular members of particle‐associated Actinobacteria were exclusively affiliated to certain actinobacterial lineages. The phylogenetic comparison of 16S rRNA gene sequences of all lakes and water layer, however, indicated the occurrence of almost similar phylogenetic lineages in all studied habitats and suggest high intracluster diversity within already known actinobacterial lineages. Non‐metric multidimensional scaling (NMS) ordination analyses and Pearson's product moment correlations revealed several strong correlations between the investigated Actinobacteria communities and various limnological parameters, such as conductivity, total phosphorous, alkalinity or primary production. However, no uniform correlation patterns were found between lakes, water layers and bacterial fractions. These heterogeneous correlation patterns together with the phylogenetic similarities of Actinobacteria communities from different lakes indicate that particular Actinobacteria represent various ecotypes or exhibit a pronounced ecophysiological plasticity.
Transcriptional response of Silicibacter pomeroyi DSS‐3 to dimethylsulfoniopropionate (DMSP)
Authors: Bürgmann Helmut , Howard Erinn C. , Ye Wenying , Sun Feng , Sun Shulei , Napierala Sarah , Moran Mary Ann 
Published: July 2007

SummaryDimethylsufoniopropionate (DMSP) is an abundant organic sulfur compound in the ocean and an important substrate for marine bacterioplankton. The Roseobacter clade of marine alphaproteobacteria, including Silicibacter pomeroyi strain DSS‐3, are known to be involved in DMSP degradation in situ. The fate of DMSP has important implications for the global sulfur cycle, but the genes involved in this process and their regulation are largely unknown. S. pomeroyi is capable of performing two major pathways of DMSP degradation, making it an important model organism. Based on the full genome sequence of this strain we designed an oligonucleotide‐based microarray for the detection of transcripts of nearly all genes. The array was used to study the transcriptional response of S. pomeroyi cultures to additions of DMSP compared to the non‐sulfur compound acetate in a time series experiment. We identified a number of upregulated genes that could be assigned to potential roles in the metabolism of DMSP. DMSP also affected the transcription of genes for transport and metabolism of peptides, amino acids and polyamines. DMSP concentration may thus also play a role as a chemical signal, indicating phytoplankton abundance and eliciting a regulatory response aimed at making maximum use of available nutrients.
Investigations of the structure and function of bacterial communities associated with Sphagnum mosses
Authors: Opelt Katja , Chobot Vladimir , Hadacek Franz , Schönmann Susan , Eberl Leo , Berg Gabriele 
Published: July 2007

SummaryHigh acidity, low temperature and extremely low concentration of nutrients form Sphagnum bogs into extreme habitats for organisms. Little is known about the bacteria associated with living Sphagnum plantlets, especially about their function for the host. Therefore, we analysed the endo‐ and ectophytic bacterial populations associated with two widely distributed Sphagnum species, Sphagnum magellanicum and Sphagnum fallax, by a multiphasic approach. The screening of 1222 isolates for antagonistic activity resulted in 326 active isolates. The bacterial communities harboured a high proportion of antifungal (26%) but a low proportion of antibacterial isolates (0.4%). Members of the genus Burkholderia (38%) were found to be the most dominant group of antagonistic bacteria. The finding that a large proportion (89%) of the antagonistic bacteria produced antifungal compounds may provide an explanation for the well‐known antimicrobial activity of certain Sphagnum species. The secondary metabolites of the Sphagnum species themselves were analysed by HPLC‐PDA. The different spectra of detected compounds may not only explain the antifungal activity but also the species specificity of the microbial communities. The latter was analysed using cultivation‐independent single‐stranded conformation polymorphism (SSCP) analysis. Using Burkholderia‐specific primers we found a high diversity of Burkholderia isolates in the endophytic and ectophytic habitats of Sphagnum. Furthermore, a high diversity of nitrogen–fixing bacteria was detected by using nifH‐specific primers, especially inside Sphagnum mosses. In conclusion, this study provides evidence that both Sphagnum species were colonized by characteristic bacterial populations, which appear to be important for pathogen defence and nitrogen fixation.
The bacterial aetiology of rosy discoloration of ancient wall paintings
Authors: Imperi Francesco , Caneva Giulia , Cancellieri Laura , Ricci Maria A. , Sodo Armida , Visca Paolo 
Published: July 2007

SummaryThe inventory of microorganisms responsible for biological deterioration of ancient paintings has become an integral part of restoration activities. Here, the microbial agent of rosy discoloration on medieval frescoes in the Crypt of the Original Sin (Matera, Italy) was investigated by a combination of microscopic, molecular and spectroscopic approaches. The bacterial community from three rosy‐discoloured painting sites was characterized by 16S rRNA gene‐based techniques. The eubacterial population was prevalently composed of Actinobacteria, among which Rubrobacter radiotolerans‐related bacteria accounted for 63–87% of the 16S rRNA gene pool per sampled site. Archaea, with prevalence of Haloarchaea‐related species, were detected in one of the three sites where they accounted for < 0.1% of the total 16S rRNA gene pool. Raman spectroscopy confirmed the identity between R. radiotolerans carotenoids (bacterioruberins) and pigments responsible for colour alteration of frescoes. This investigation provides the first evidence of a causal relationship between heavy contamination by Rubrobacter‐related bacterioruberin‐producing bacteria and rosy discoloration of ancient wall paintings.
Flow of information for emotions through temporal and orbitofrontal pathways
Authors: Barbas Helen 
Published: July 2007

AbstractThe posterior orbitofrontal cortex, anterior temporal sensory association areas and the amygdala have a key role in emotional processing and are robustly interconnected. By analogy with the pattern of connections in early processing sensory areas, anterior temporal sensory and polymodal association cortices send primarily feedforward projections to posterior orbitofrontal cortex and to the amygdala originating in the supragranular layers, in pathways that may provide signals about the external environment. The amygdala innervates all layers of the posterior orbitofrontal cortex, including the middle, or feedforward, target layers, in a pathway that may convey information about emotional context. The posterior orbitofrontal cortex targets dual systems in the amygdala which have opposite effects on central autonomic structures. Both pathways originate in posterior orbitofrontal cortex, but one targets heavily the inhibitory intercalated masses, whose activation can ultimately disinhibit central autonomic structures during emotional arousal. The other pathway innervates the central nucleus of the amygdala, and can lead to downstream inhibition of central autonomic structures, resulting in autonomic homeostasis. The choice of pathway may depend on emotional context, and probably involves other prefrontal areas, including lateral prefrontal areas, which have executive functions. Lateral prefrontal cortices issue feedforward projections that target layer 5 of orbitofrontal cortex, which is the chief output layer to the amygdala. These laminar‐specific pathways suggest sequential and collaborative interactions in evaluating the sensory and emotional aspects of the environment for decision and action in complex behaviour.
Evolution of the amygdaloid complex in vertebrates, with special reference to the anamnio‐amniotic transition
Authors: Moreno Nerea , González Agustín 
Published: July 2007

AbstractNumerous studies over the last few years have demonstrated that the amygdaloid complex in amniotes shares basic developmental, hodological and neurochemical features. Furthermore, homologous territories of all the main amygdaloid subdivisions have been recognized among amniotes, primarily highlighted by the common expression patterns for numerous developmental genes. Thus, derivatives from the lateral pallium, ventral pallium and subpallium constitute the fundamental parts of the amygdaloid complex. With the development of new technical approaches, study of the precise neuroanatomy of the telencephalon of the anuran amphibians (anamniotes) has been possible. Current embryological, hodological and immunohistochemical evidence strongly suggests that most of the structures present in amniotes are recognizable in these anamniotes. These investigations have yielded enough results to support the notion that the organization of the anuran amygdaloid complex includes subdivisions with their origin in ventral pallial and subpallial territories; a strong relationship with the vomeronasal and olfactory systems; abundant intra‐amygdaloid connections; a main output centre involved in the autonomic system; recognizable amygdaloid fibre systems; and distinct chemoarchitecture. Therefore, the new ideas regarding the amygdaloid evolution based on the recent findings in anamniotes, and especially in anurans, strongly support the notion that basic amygdaloid structures were present at least in the brain of ancestral tetrapods organized following a basic plan shared by tetrapods.
Repeated amphetamine treatment increases phosphorylation of extracellular signal‐regulated kinase, protein kinase B, and cyclase response element‐binding protein in the rat striatum
Authors: Shi Xiangdang , McGinty Jacqueline F. 
Published: July 2007

AbstractExtracellular signal‐regulated kinases, protein kinase B/Akt and cyclase response element‐binding protein play important roles in drug‐induced neuroadaptations. Acute psychostimulant exposure rapidly alters the phosphorylation of these proteins in the striatum but less is known about their responses to repeated stimulant administration. In this study the phosphorylated state of these proteins in rat striatum was analyzed by immunoblotting 15 min and 2 h after amphetamine (AMPH)‐induced behavioral sensitization. Two weeks after the last dose of 5 mg/kg, i.p. AMPH once daily for 5 days, rats were challenged with 1 mg/kg, i.p. AMPH or saline and sacrificed 15 min or 2 h later. Sensitization to AMPH‐induced behavioral activity was observed in AMPH pre‐treated rats after AMPH on the challenge day. Phosphorylation of all three proteins was significantly greater 15 min after AMPH in AMPH‐pre‐treated than in saline‐pre‐treated rats. Two hours after AMPH challenge in AMPH‐pre‐treated rats, phospho‐extracellular signal‐regulated kinase and phospho‐cAMP response element‐binding protein immunoreactivity was still significantly elevated but not after AMPH injection in saline‐pre‐treated rats. In contrast, phospho‐Akt was down‐regulated to the same extent 2 h after acute AMPH or repeated AMPH with an AMPH challenge. These data implicate differential regulation of phospho‐extracellular signal‐regulated kinase, phospho‐cAMP response element‐binding protein versus phospho‐Akt in sensitized responses to AMPH.
Non‐charged amino acids from three different domains contribute to link agonist binding to channel gating in α7 nicotinic acetylcholine receptors
Authors: Aldea Marcos , Mulet José , Sala Salvador , Sala Francisco , Criado Manuel 
Published: July 2007

AbstractBinding of agonists to nicotinic acetylcholine receptors results in channel opening. Previously, we have shown that several charged residues at three different domains of the α7 nicotinic receptor are involved in coupling binding and gating, probably through a network of electrostatic interactions. This network, however, could also be integrated by other residues. To test this hypothesis, non‐charged amino acids were mutated and expression levels and electrophysiological responses of mutant receptors were determined. Mutants at positions Asn47 and Gln48 (loop 2), Ile130, Trp134, and Gln140 (loop 7), and Thr264 (M2–M3 linker) showed poor or null functional responses, despite significant membrane expression. By contrast, mutants F137A and S265A exhibited a gain of function effect. In all cases, changes in dose–response relationships were small, EC50 values being between threefold smaller and fivefold larger, arguing against large modifications of agonist binding. Peak currents decayed at the same rate in all receptors except two, excluding large effects on desensitization. Thus, the observed changes could be mostly caused by alterations of the gating characteristics. Moreover, analysis of double mutants showed an interconnection between some residues in these domains, especially Gln48 with Ile130, suggesting a potential coupling between agonist binding and channel gating through these amino acids.
Efficiency and Outcomes of Emergent Vascular Access Procedures Performed at a Dedicated Outpatient Vascular Access Center
Authors: Kian Kaveh , Takesian Kamla , Wyatt Christina , Assalotti Joseph , Mishler Rick , Schon Donald 
Published: July 2007

AbstractThe outpatient vascular access center (VAC) may have an important impact in improving the outcomes of emergent procedures on nonfunctioning hemodialysis access. An emergent procedure is defined as the absence of a functioning access for hemodialysis, including thrombosed graft or fistula, nonfunctioning dialysis catheters, and the need for access to initiate emergent hemodialysis.The aim of this study was to prospectively evaluate the efficiency and outcomes of all consecutive emergent hemodialysis access procedures during a 3‐month period at a single high volume VAC. Data collection for each procedure included anatomic outcome, clinical outcome, the amount of time from referral to procedure and to successful dialysis, 2‐week‐follow‐up to screen for postprocedure complications and fluoroscopy time.A total of 157 emergent procedures were performed in 136 patients with the majority of interventions on nonfunctioning grafts and tunneled catheters. The overall clinical success (defined as successful postprocedure completion of at least one dialysis treatment at the prescribed blood flow) was achieved in 149 out of 157 (95%) cases. 90% of subjects completed their procedure within 24 hours of the initial referral to the VAC. The study also demonstrated a rapid turn around time, with successful dialysis being performed within 24 hours of referral in 61% and within 48 hours in 90% of referrals.This is the first study to demonstrate both the efficiency and successful outcomes of an outpatient vascular access center in treating emergent vascular access problems.
PHOSPHORUS METABOLISM AND MANAGEMENT IN CHRONIC KIDNEY DISEASE: Expanding Role for Vitamin D in Chronic Kidney Disease: Importance of Blood 25‐OH‐D Levels and Extra‐Renal 1α‐Hydroxylase in the Classical and Nonclassical Actions of 1α,25‐Dihydroxyvitamin D3
Authors: Jones Glenville 
Published: July 2007

AbstractRecent advances in the understanding of vitamin D have revolutionized our view of this old nutritional factor and suggested that it has much wider effects on the body than ever believed before. In addition to its well‐known effects on calcium/phosphate homeostasis, vitamin D, through its hormonal form, 1α,25‐dihydroxyvitamin D3 or calcitriol, is a cell differentiating factor and anti‐proliferative agent with actions on a variety of tissues around the body (e.g., skin, muscle, immune system). By influencing gene expression in multiple tissues, calcitriol influences many physiological processes besides calcium/phosphate homeostasis including muscle and keratinocyte differentiation, insulin secretion, blood pressure regulation, and the immune response. The incidence of various diseases including epithelial cancers, multiple sclerosis, muscle weakness as well as bone‐related disorders has been correlated with vitamin D deficiency/insufficiency and has led to a re‐evaluation of recommended daily intakes both in the normal subject and CKD patient. Critical developments have been the emergence of the value of blood 25‐OH‐D measurement as a tool in predicting vitamin D‐related problems and this has in turn emphasized the importance of the extra‐renal version of the 1α‐hydroxylase, the enzyme responsible for the final step in vitamin D activation. The widespread expression of this extra‐renal enzyme supports the view that it exists to boost intracellular concentrations of calcitriol within some target tissues in order to modulate a unique set of genes specifically in those tissues, a process which is therefore dependent upon circulating 25‐OH‐D. For CKD patients with their tendency to vitamin D substrate insufficiency coupled with their documented loss of the renal 1α‐hydroxylase in late stages, this new information has profound implications. Physicians must start to manage the vitamin D insufficiency by vitamin D supplements throughout stages 1–5 whilst continuing to provide calcitriol replacement therapy, in the form of calcitriol or its analogs, in stages 3–5.
PHOSPHORUS METABOLISM AND MANAGEMENT IN CHRONIC KIDNEY DISEASE: Phosphate Metabolism in the Setting of Chronic Kidney Disease: Significance and Recommendations for Treatment
Authors: Kestenbaum Bryan 
Published: July 2007

AbstractPhosphorus is an essential mineral that plays a crucial role in cell structure and metabolism. In living organisms, phosphorus exists surrounded by four oxygen atoms to form phosphate (PO4). Within cells, PO4regulates enzymatic activity and serves as an essential component of nucleic acids, adenosine triphosphate, and phospholipid membranes. Outside cells, PO4primarily resides in bone and teeth as hydroxyapatite. A small amount of inorganic PO4circulates in serum, with levels balanced by gastrointestinal intake, renal excretion, and a set of specific hormones. Under normal conditions, PO4is excreted through the kidneys. Among patients with end stage renal disease (ESRD) receiving chronic dialysis, circulating PO4levels typically rise to levels well above the normal laboratory range. Higher serum PO4levels are strongly associated with arterial calcification and mortality in this setting. Among predialysis patients with chronic kidney disease (CKD), phosphaturic hormones enhance renal PO4excretion to maintain serum PO4levels within the high‐normal laboratory range. Recently, high‐normal serum PO4levels have been associated with cardiovascular (CV) events and mortality among individuals who have CKD and among those who have normal kidney function. This review discusses PO4metabolism in the context of CKD, examines associations of PO4levels with adverse outcomes in the CKD setting, and suggests treatment strategies for moderating serum PO4levels.
PHOSPHORUS METABOLISM AND MANAGEMENT IN CHRONIC KIDNEY DISEASE: Role of Fibroblast Growth Factor 23 in Phosphate Homeostasis and Pathogenesis of Disordered Mineral Metabolism in Chronic Kidney Disease
Authors: Stubbs Jason , Liu Shiguang , Quarles L. Darryl 
Published: July 2007

AbstractThe discovery of fibroblast growth factor 23 (FGF23), a novel bone‐derived hormone that inhibits phosphate reabsorption and calcitriol production by the kidney, has uncovered primary regulatory pathways and new systems biology governing bone mineralization, vitamin D metabolism, parathyroid gland function and renal phosphate handling. This phosphaturic hormone, which is made predominately by osteocytes in bone, appears to have a physiologic role as a counter‐regulatory hormone for vitamin D. Evidence has also emerged to support the existence of a bone–kidney axis to coordinate the mineralization of bone with renal handling of phosphate. Pathologically, high circulating levels of FGF23 result in hypophosphatemia, decreased production of 1,25(OH)2D, elevated parathyroid hormone and rickets/osteomalacia in patients with functioning kidneys, whereas low levels are associated with tumoral calcinosis, hyperphosphatemia and elevated 1,25(OH)2D. In addition, patients with chronic kidney disease (CKD) exhibit marked elevations of circulating FGF23. While the significance of increased FGF23 levels in CKD remains to be defined, it might contribute to phosphate excretion and suppression of 1,25(OH)2D levels in CKD stages 3 and 4, as well as potentially contribute to secondary hyperparathyroidism through direct actions on the parathyroid gland in more advanced renal failure. As our knowledge expands regarding the regulation and functions of FGF23, the assessment of FGF23 will become an important diagnostic marker as well as a therapeutic target for management of disordered mineral metabolism in a variety of acquired and hereditary disorders.