bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dextromethorphan is protective against sensitized N‐methyl‐d‐aspartate receptor‐mediated excitotoxic brain damage in the developing mouse brain
Authors: Keller Matthias , Griesmaier Elke , Auer Maria , Schlager Gerald , Urbanek Martina , Simbruner Georg , Gressens Pierre , Sárközy Gergely 
Published: February 2008

AbstractEnhanced glutamate release and inflammation play an important role in the pathogenesis of developmental brain injury. Although N‐methyl‐d‐aspartate receptor (NMDAR) antagonists potently attenuate neonatal brain damage in several animal models, they can also impact trophic functions in the developing brain. As a consequence, high‐affinity NMDAR antagonists have been shown to trigger widespread apoptotic neurodegeneration in the newborn brain. Dextromethorphan (DM), a low‐affinity NMDAR antagonist with anti‐inflammatory properties, may be neuroprotective against excitotoxic and inflammation‐enhanced excitotoxic brain injury, without the associated stimulation of apoptotic degeneration. Using an established newborn mouse model of excitotoxic brain damage, we determined whether systemic injection of DM significantly attenuates excitotoxic lesion size. We investigated several doses and time regimens; a dose of 5 µg/g DM given in a combination of both pre‐injury and repetitive post‐injury treatment proved most effective. DM treatment significantly reduced lesion size in gray and white matter by reducing cell death as shown by a decreased Fluoro‐Jade B staining and caspase‐3 activation. Pre‐treatment with interleukin‐1β and lipopolysaccharide enhanced NMDAR‐mediated excitotoxic brain injury and microglial cell activation. This sensitizing effect was abolished by DM treatment, as the effectiveness of DM in reducing lesion size and microglial cell activation was similar to phosphate‐buffered saline‐pre‐treated controls. In all cases, no gender‐specific differences were detected. DM treatment did not trigger any apoptotic neurodegeneration (caspase‐3 cleavage, terminal deoxynucleotidyl transferase‐mediated dUTP nick‐end labeling, Fluoro‐Jade B staining). Although functional parameters were not measured, our data corroborate reports that DM is neuroprotective and that it may therefore improve functional outcome following perinatal brain injury.
Left mid‐ventrolateral prefrontal cortex: underlying principles of function
Authors: Kostopoulos Penelope , Petrides Michael 
Published: February 2008

AbstractThere is a growing body of evidence indicating that the mid‐ventrolateral prefrontal cortex in the left hemisphere is involved in some aspect of controlled verbal memory retrieval. Its precise role, however, remains unclear. We tested the hypothesis that when stimuli in memory are related to each other in multiple ways, and therefore familiarity, strong constant stimulus–stimulus links or contextual cues are not sufficient for successful retrieval, control processing emanating from the mid‐ventrolateral prefrontal cortex is required to disambiguate and select the appropriate information among memory traces. We refer to this type of retrieval as active retrieval to distinguish it from automatic retrieval which depends on the simple reactivation of memory traces. Normal human subjects were scanned with functional magnetic resonance imaging while they performed three memory tasks that varied in their demands on active retrieval of verbal information. As the demands on active retrieval increased, there was an increase in the activity within the mid‐ventrolateral prefrontal cortex, bilaterally, but with more prominent activity in the left hemisphere. These activity increases correlated with activity in the posterior temporal region which, in the left hemisphere, is involved in language processing. No significant activity increases were observed in any other prefrontal region. Furthermore, for the retrieval of well‐learned verbally cued conditional motor associations, there were no activity increases in the mid‐ventrolateral prefrontal cortex. The present findings provide strong support for the hypothesis that the mid‐ventrolateral prefrontal cortex, particularly in the left hemisphere, plays a major role in the active retrieval of information from verbal memory.
Effects of FAK ablation on cerebellar foliation, Bergmann glia positioning and climbing fiber territory on Purkinje cells
Authors: Watanabe Fumihiro , Miyazaki Taisuke , Takeuchi Tomonori , Fukaya Masahiro , Nomura Takanori , Noguchi Shigeru , Mori Hisashi , Sakimura Kenji , Watanabe Masahiko , Mishina Masayoshi 
Published: February 2008

AbstractFocal adhesion kinase (FAK) is a non‐receptor tyrosine kinase that is widely expressed in the brain, and plays key roles in various cellular processes in response to both extracellular and intracellular stimuli. Here, we explored the role of FAK in cerebellar development. In the mouse cerebellum, FAK was found to be distributed as tiny cytoplasmic aggregates in various neuronal and glial elements, including Purkinje cells (PCs), Bergmann glia (BG), parallel fiber (PF)‐terminals and climbing fiber (CF)‐terminals. The neuron/glia‐specific ablation of FAK impaired cerebellar foliation, such as variable decreases in foliation sizes and the lack of intercrural and precentral fissures. Some of the BG cells became situated ectopically in the molecular layer. Furthermore, the FAK ablation altered the innervation territories of CFs and PFs on PCs. CF innervation regressed to the basal portion of proximal dendrites and somata, whereas ectopic spines protruded from proximal dendrites and PFs expanded their territory by innervating the ectopic spines. Furthermore, the persistence of surplus CFs innervating PC somata caused multiple innervation. When FAK was selectively ablated in PCs, diminished dendritic innervation and persistent somatic innervation by CFs were observed, whereas cerebellar foliation and cell positioning of BG were normally retained. These results suggest that FAK in various neuronal and glial elements is required for the formation of normal histoarchitecture and cytoarchitecture in the cerebellum, and for the construction of proper innervation territory and synaptic wiring in PCs.
Long‐term reorganization of respiratory pathways after partial cervical spinal cord injury
Authors: Vinit Stéphane , Darlot Fannie , Stamegna Jean‐Claude , Sanchez Patrick , Gauthier Patrick , Kastner Anne 
Published: February 2008

AbstractHigh cervical spinal cord injury (SCI) interrupts bulbospinal respiratory pathways innervating phrenic motoneurons, and induces an inactivation of phrenic nerves (PN) and diaphragm. We have previously shown that the ipsilateral (ipsi) PN was inactivated following a lateral C2 SCI, but was spontaneously partially reactivated 7 days post‐SCI. This phrenic reactivation depended on contralateral (contra) descending pathways, located laterally, that cross the spinal midline. We analysed here whether long‐term post‐lesional changes may occur in the respiratory network. We showed that ipsi PN reactivation was greater at 3 months compared with 7 days post‐SCI, and that it was enhanced after acute contra phrenicotomy (Phx), which also induced a substantial reactivation of the ipsi diaphragm (not detected at 7 days post‐SCI). At 3 months post‐SCI (compared with 7 days post‐SCI), ipsi PN activity was only moderately affected by ipsi Phx or by gallamine treatment, a nicotinic neuromuscular blocking agent, indicating that it was less dependent on ipsi sensory phrenic afferents. After an additional acute contra SCI (C1) performed laterally, ipsi PN activity was abolished in rats 7 days post‐SCI, but persisted in rats 3 months post‐SCI. This activity thus depended on new functional descending pathways located medially rather than laterally. These may not involve newly recruited neurons as retrograde labelling showed that ipsi phrenic motoneurons were innervated by a similar number of medullary respiratory neurons after a short and long post‐lesional time. These results show that after a long post‐lesional time, phrenic reactivation is reinforced by an anatomo‐functional reorganization of spinal respiratory pathways.
Dynamics of action potential backpropagation in basal dendrites of prefrontal cortical pyramidal neurons
Authors: Zhou Wen‐Liang , Yan Ping , Wuskell Joseph P. , Loew Leslie M. , Antic Srdjan D. 
Published: February 2008

AbstractBasal dendrites of neocortical pyramidal neurons are relatively short and directly attached to the cell body. This allows electrical signals arising in basal dendrites to strongly influence the neuronal output. Likewise, somatic action potentials (APs) should readily propagate back into the basilar dendritic tree to influence synaptic plasticity. Two recent studies, however, determined that sodium APs are severely attenuated in basal dendrites of cortical pyramidal cells, so that they completely fail in distal dendritic segments. Here we used the latest improvements in the voltage‐sensitive dye imaging technique (Zhou et al., 2007) to study AP backpropagation in basal dendrites of layer 5 pyramidal neurons of the rat prefrontal cortex. With a signal‐to‐noise ratio of > 15 and minimal temporal averaging (only four sweeps) we were able to sample AP waveforms from the very last segments of individual dendritic branches (dendritic tips). We found that in short‐ (< 150 µm) and medium (150–200 µm in length)‐range basal dendrites APs backpropagated with modest changes in AP half‐width or AP rise‐time. The lack of substantial changes in AP shape and dynamics of rise is inconsistent with the AP‐failure model. The lack of substantial amplitude boosting of the third AP in the high‐frequency burst also suggests that in short‐ and medium‐range basal dendrites backpropagating APs were not severely attenuated. Our results show that the AP‐failure concept does not apply in all basal dendrites of the rat prefrontal cortex. The majority of synaptic contacts in the basilar dendritic tree actually received significant AP‐associated electrical and calcium transients.
Isolation and identification of amoeba‐resisting bacteria from water in human environment by using an Acanthamoeba polyphaga co‐culture procedure
Authors: Pagnier Isabelle , Raoult Didier , La Scola Bernard 
Published: February 2008

SummaryAmoeba‐resisting bacteria (ARB) such as Legionella spp. are currently regarded as potential human pathogens living in the environment. To detect ARB from both human and environmental samples, co‐culture with amoebae has been demonstrated as an efficient tool. However, using this procedure, mostly water from cooling towers and hospital water supplies have been investigated as the possible reservoir of ARB. In the present study, we studied ARB population in 77 environmental water samples including rivers, fountains, lakes and domestic wells in the south of France. As a result, a total of 244 isolates corresponding to 89 different species of ARB, but not Legionella spp., were identified. Ability to grow within and/or to be lytic for amoebae was revealed for the first time for several human pathogens. Six isolates are likely to be the members of a new or uncharacterized genus/species. An anaerobic bacterium, Clostridium frigidicarnis was demonstrated to be lytic for amoebae. This preliminary work demonstrates that the water environment in the vicinity of humans is a reservoir of ARB, including well‐known pathogens for which amoebae and/or water was not recognized earlier as a possible reservoir.
Characterization of a homogeneous taxonomic group of marine magnetotactic cocci within a low tide zone in the China Sea
Authors: Pan Hongmiao , Zhu Kailing , Song Tao , Yu‐Zhang Kui , Lefèvre Christopher , Xing Sue , Liu Min , Zhao Sanjun , Xiao Tian , Wu Long‐Fei 
Published: February 2008

SummaryMagnetotactic bacteria are a heterologous group of motile prokaryotes, ubiquitous in aquatic habitats and cosmopolitan in distribution. Here, we studied the diversity of magnetotactic bacteria in a seawater pond within an intertidal zone at Huiquan Bay in the China Sea. The pond is composed of a permanently submerged part and a low tide subregion. The magnetotactic bacteria collected from the permanently submerged part display diversity in morphology and taxonomy. In contrast, we found a virtually homogenous population of ovoid‐coccoid magnetotactic bacteria in the low tide subregion of the pond. They were bilophotrichously flagellated and exhibited polar magnetotactic behaviour. Almost all cells contained two chains of magnetosomes composed of magnetite crystals. Intriguingly, the combination of restriction fragment length polymorphism analysis (RFLP) and sequencing of cloned 16S rDNA genes from the low tide subregion samples as well as fluorescence in situ hybridization (FISH) revealed the presence of a homogenous population. Moreover, phylogenetic analysis indicated that the Qingdao Huiquan low tide magnetotactic bacteria belong to a new genus affiliated with the α‐subclass of Proteobacteria. This finding suggests the adaptation of the magnetotactic bacterial population to the marine tide.
Gene transcript analysis of assimilatory iron limitation in Geobacteraceae during groundwater bioremediation
Authors: O'Neil Regina A. , Holmes Dawn E. , Coppi Maddalena V. , Adams Lorrie A. , Larrahondo M. Juliana , Ward Joy E. , Nevin Kelly P. , Woodard Trevor L. , Vrionis Helen A. , N'Guessan A. Lucie , Lovley Derek R. 
Published: February 2008

SummaryLimitations on the availability of Fe(III) as an electron acceptor are thought to play an important role in restricting the growth and activity of Geobacter species during bioremediation of contaminated subsurface environments, but the possibility that these organisms might also be limited in the subsurface by the availability of iron for assimilatory purposes was not previously considered because copious quantities of Fe(II) are produced as the result of Fe(III) reduction. Analysis of multiple Geobacteraceae genomes revealed the presence of a three‐gene cluster consisting of homologues of two iron‐dependent regulators, fur and dtxR (ideR), separated by a homologue of feoB, which encodes an Fe(II) uptake protein. This cluster appears to be conserved among members of the Geobacteraceae and was detected in several environments. Expression of the fur‐feoB‐ideR cluster decreased as Fe(II) concentrations increased in chemostat cultures. The number of Geobacteraceae feoB transcripts in groundwater samples from a site undergoing in situ uranium bioremediation was relatively high until the concentration of dissolved Fe(II) increased near the end of the field experiment. These results suggest that, because much of the Fe(II) is sequestered in solid phases, Geobacter species, which have a high requirement for iron for iron‐sulfur proteins, may be limited by the amount of iron available for assimilatory purposes. These results demonstrate the ability of transcript analysis to reveal previously unsuspected aspects of the in situ physiology of microorganisms in subsurface environments.
Novel lineages of Planctomycetes densely colonize the alkaline gut of soil‐feeding termites (Cubitermes spp.)
Authors: Köhler Tim , Stingl Ulrich , Meuser Katja , Brune Andreas 
Published: February 2008

SummaryMembers of the phylum Planctomycetes are found in aquatic and terrestrial habitats. Here we show that the highest density of Planctomycetes in natural environments (2.6 × 109 cells ml−1) is encountered in the hindgut of soil‐feeding termites (Cubitermes spp.), where they constitute up to one‐third of the bacteria in the alkaline P3 compartment detected by fluorescent in situ hybridization (FISH). A 16S‐rRNA‐based approach revealed that the planctomycete community is very diverse and falls into three major clusters representing novel, deeply branching lineages. Terminal restriction fragment length polymorphism (T‐RFLP) analysis and FISH with cluster‐specific oligonucleotide probes confirmed that most of the lineages are also present in other gut compartments, albeit in much lower numbers, but absent from the food soil. The majority of planctomycetes in the gut belong to a large clade, the ‘Termite planctomycete cluster’, which consists exclusively of clones from termite guts and seems to be represented in all termite species.
Resilience of the rhizosphere Pseudomonas and ammonia‐oxidizing bacterial populations during phytoextraction of heavy metal polluted soil with poplar
Authors: Frey Beat , Pesaro Manuel , Rüdt Andreas , Widmer Franco 
Published: February 2008

SummaryWe assessed the effects of phytoextraction on the dynamics of Pseudomonas spp. and ammonia‐oxidizing bacterial populations in a heavy metal (HM) polluted soil. Hybrid poplars were grown in two‐compartment root containers with a medium history (> 4 years) of HM pollution for 13 weeks. Bulk and poplar rhizosphere soils were analysed by denaturing gradient gel electrophoresis (DGGE) of Pseudomonas (sensu stricto) 16S rRNA and amoA gene fragments. DGGE patterns revealed that Pseudomonas and amoA‐containing populations in the contaminated soils were markedly different from those in the uncontaminated soils. Pseudomonas and amoA profiles appeared to be stable over time in the bulk soils. In contrast, contaminated rhizosphere soils revealed a clear shift of populations with removal of HM becoming similar or at least shifted to the populations of the uncontaminated soils. The effect of phytoextraction was, however, not evident in the bulk samples, which still contained large amounts of HM. Cloning and sequencing of dominant DGGE bands revealed that Pseudomonas were phylogenetically related to the Pseudomonas fluorescens cluster and the amoA sequences to Nitrosospira spp. At the last sampling, major prominent band sequences from contaminated rhizosphere soils were identical to sequences obtained from uncontaminated rhizosphere soils, indicating that the populations were dominated by the same phylotypes. This study suggests that two taxonomically different populations are able to recover after the relief of HM stress by phytoextraction practices, whereas bulk microbial activities still remained depressed.
Insulin sensitivity in Type 1 diabetic children and adolescents
Authors: Szadkowska A. , Pietrzak I. , Mianowska B. , Bodalska‐Lipińska J. , Keenan H. A. , Toporowska‐Kowalska E. , Młynarski W. , Bodalski J. 
Published: February 2008

AbstractAim  To estimate insulin sensitivity in Type 1 diabetic children and adolescents, and assess the relationship between insulin sensitivity and clinical markers of adiposity and parameters of the metabolic syndrome.Methods  A total of 202 patients aged 8–18 years with Type 1 diabetes and disease duration 1.5–15 years participated. Insulin sensitivity was estimated by glucose uptake during an euglycaemic–hyperinsulinaemic clamp and was calculated as the average amount of glucose (Mlbm = mg/kglbm/min) required to maintain euglycaemia. Blood pressure, glycated haemoglobin (HbA1c) and lipid concentrations were measured.Results  The Mlbm value ranged from 4.14 to 25.25 mg/kglbm/min (mean 9.81 ± 3.34 mg/kglbm/min). There was a significant relationship between M value and patients’ age (r = –0.38, P < 0.0001). Insulin sensitivity decreased significantly with the onset of puberty; hence, it was significantly lower in pubertal and post‐pubertal adolescents. Girls were significantly more insulin resistant than boys (9.01 ± 0.32 vs. 10.43 ± 0.29 mg/kglbm/min, P = 0.005). Insulin sensitivity correlated with body mass index (r = –0.29, P < 0.001), waist circumference (r = –0.35, P < 0.001), triceps skin fold (r = –0.17, P = 0.018), subscapular skin fold (r = –0.23, P = 0.001) and body fat (r = –0.19, P = 0.006). There was a relationship between Mlbm value, cholesterol (r = –0.18, P = 0.012), high‐density lipoprotein cholesterol (r = 0.15, P = 0.035), low‐density lipoprotein cholesterol (r = –0.22, P = 0.002), triglycerides (r = –0.32, P < 0.001) and systolic blood pressure (r = –0.15, P = 0.029). Insulin resistance was related to HbA1c (r = –0.18, P = 0.012). Additionally, there was a correlation between Mlbm value and insulin dose.Conclusions  Children and adolescents with Type 1 diabetes mellitus have a very wide range of insulin sensitivity, which is determined by sex, age, amount of adipose tissue and glycaemic control.
Plastid targeting strategies for cyanophycin synthetase to achieve high‐level polymer accumulation in Nicotiana tabacum
Authors: Hühns Maja , Neumann Katrin , Hausmann Tina , Ziegler Karl , Klemke Friederike , Kahmann Uwe , Staiger Dorothee , Lockau Wolfgang , Pistorius Elfriede K. , Broer Inge 
Published: February 2008

SummaryThe production of biodegradable polymers in transgenic plants is an important challenge in plant biotechnology; nevertheless, it is often accompanied by reduced plant fitness. In order to decrease the phenotypic abnormalities caused by cytosolic production of the biodegradable polymer cyanophycin, and to increase polymer accumulation, four translocation pathway signal sequences for import into chloroplasts were individually fused to the coding region of the cyanophycin synthetase gene (cphATe) of Thermosynechococcus elongatus BP‐1, resulting in the constructs pRieske‐cphATe, pCP24‐cphATe, pFNR‐cphATe and pPsbY‐cphATe. These constructs were expressed in Nicotiana tabacum var. Petit Havana SRI under the control of the constitutive cauliflower mosaic virus (CaMV) 35S promoter. Three of the four constructs led to polymer production. However, only the construct pPsbY‐cphATe led to cyanophycin accumulation exclusively in chloroplasts. In plants transformed with the pCP24‐cphATe and pFNR‐cphATe constructs, water‐soluble and water‐insoluble forms of cyanophycin were only located in the cytoplasm, which resulted in phenotypic changes similar to those observed in plants transformed with constructs lacking a targeting sequence. The plants transformed with pPsbY‐cphATe produced predominantly the water‐insoluble form of cyanophycin. The polymer accumulated to up to 1.7% of dry matter in primary (T0) transformants. Specific T2 plants produced 6.8% of dry weight as cyanophycin, which is more than five‐fold higher than the previously published value. Although all lines tested were fertile, the progeny of the highest cyanophycin‐producing line showed reduced seed production compared with control plants.
Immunomodulation of bioactive gibberellin confers gibberellin‐deficient phenotypes in plants
Authors: Suzuki Yoshihito , Mizuno Toru , Urakami Eriko , Yamaguchi Isomaro , Asami Tadao 
Published: February 2008

SummaryImmunomodulation is a means to modulate an organism's function by antibody production to capture either endogenous or exogenous antigens. This method was applied to plants to repress the function of gibberellins (GAs), a class of phytohormones responsible for plant elongation, by anti‐bioactive GA antibodies. Two different antibodies were produced in Arabidopsis as single‐chain variable fragment (scFv) fused to green fluorescent protein (GFP) with four different subcellular localizations: endoplasmic reticulum (ER), cytosol, apoplastic space or the outer surface of the plasma membrane. When targeting scFv‐GFP to ER, plants showed the highest accumulation of scFv‐GFP, with binding activity, strong GFP fluorescence in ER‐derived compartments and mild but clear GA‐deficient phenotypes, including a smaller leaf size, delayed bolting, shorter inflorescence length and decreased germination. Plants expressing scFv‐GFP in ER responded to exogenous GA4 and contained 15–40 times greater endogenous GA4 than wild‐type plants. They also showed increased gene expression for GA3ox1, GA20ox1 and GA20ox2, but decreased expression for GA2ox1, which are feedback and feedforward regulated by GA signalling, respectively. These results suggest that the level of free functional GA4 decreased when trapped in the ER with scFv to the extent that mild GA‐deficient phenotypes were created. A dramatic increase in the total sum of GA4 (free plus scFv‐GFP bound) was detected as a result of the up‐regulation of GA biosynthesis (feedback regulated), and a decrease in GA4 catabolism as a result of protection by scFv‐GFP binding. This study demonstrates that the use of immunomodulation to inhibit the action of bioactive GAs is an effective method of creating GA‐deficient plants.