bluuebunny/crossref_metadata_2025 huggingface dataset:
Mapping polygenes for tuber resistance to late blight in a diploid Solanum phureja × S. stenotomum hybrid population
Authors: Simko I. , Costanzo S. , Ramanjulu V. , Christ B. J. , Haynes K. G.
Published: July 2006

Potato tuber blight is a disease caused by the oomycete Phytophthora infestans (Mont.) de Bary. Due to the significant economic impact of this disease, introgression of durable resistance into the cultivated potato is one of the top priorities of breeding programmes worldwide. Though numerous resistance loci against this devastating disease have already been mapped, most of the detected loci are contributing towards foliar resistance while specific information on tuber resistance is limited. To identify the genetic components of tuber resistance and its relationship to foliar resistance and plant maturity we have investigated the host‐pathogen interaction in a segregating diploid hybrid Solanum phureja × S. stenotomum family. Mature tubers from this mapping family were inoculated with a sporangial suspension of P. infestans (US‐8 clonal lineage) and evaluated for lesion expansion. No significant correlation was detected between late blight resistance in foliage and tubers, and between plant maturity and tuber resistance. Four chromosomal regions were significantly associated with tuber resistance to the disease. The largest effect was detected near the marker locus PSC (LOD 10.7) located on chromosome 10. This locus explained about 63% of the total phenotypic variation of the trait. The other three resistance‐related loci were mapped on chromosomes 8 (GP1282, LOD 4.4), 6 (CP18, LOD 4.0) and 2 (CP157, LOD 3.8). None of the four tuber resistance loci coincides with the foliage resistance loci detected in this same family. Tuber blight resistance quantitative trait loci (QTL) on chromosomes 2, 8 and 10 are distinct from the maturity QTLs and have an additive effect on tuber resistance. These results indicate that different genes are involved in foliar and tuber resistance to P. infestans in the present family and that some of the resistance genes might be associated with late maturity.
New interspecific rice genome constructions obtained by symmetric cell fusion
Authors: Feng Y. Y. , Takahashi H. , Akagi H. , Mori K.
Published: July 2006

Newly released rice varieties are mostly progenies of common commercial cultivars and so most gene sources for rice breeding have closely related genotypes. Protoplast fusion technique is a method that can produce hybrid plants in one‐step within a desired cultivar. To introduce new genetic diversity into rice‐breeding materials, hybrids between Oryza sativa L. (AA) and Oryza punctata Kotschy ex Steud. (BBCC) were generated by symmetric protoplast fusion. The genomic distribution in interspecific somatic hybrids was investigated by multi‐colour genomic in situ hybridization. Differences in chromosome numbers were observed not only between different somatic hybrid plants but also within individual hybrid plants. Chromosomal reduction of the A genome was found in two somatic hybrids. These results suggest that it is possible to reconstruct new interspecific rice genomes. Chromosomal reduction in interspecific somatic hybrids may be used to generate breeding lines with novel chromosomal constitutions.
Male gamete development and early tapetal degeneration in cytoplasmic male‐sterile pepper investigated by meiotic, anatomical and ultrastructural analyses
Authors: Luo X.‐D. , Dai L.‐F. , Wang S.‐B , Wolukau J. N. , Jahn M. , Chen J.‐F.
Published: July 2006

Cytoplasmic male‐sterile (CMS) pepper (Capsicum annuum L.) is a useful germplasm for heterosis breeding, however, the process of male gamete development and the sterility mechanism is unclear. In the present study, the developmental sequence in CMS pepper and the causative factors responsible for pollen abortion were investigated through combined meiotic analysis, paraffin section observations, and transmission electron microscopy. Results from meiotic analysis showed that meiosis in a male‐sterile inbred line, CMS 21A, was normal, and uni‐nucleate pollen could be released from the tetrads of both CMS 21A and the fertile maintainer line 21B. However, only the uni‐nucleate pollen from CMS 21B could develop into functional gametes, while the uni‐nucleate pollen from the 21A went through a process of rupture, and the cellular components were released into the anther sac. Observations of paraffin sections viewed with the light microscope showed that the tapetum of CMS 21A at the uni‐nucleate stage swelled abnormally and was pressed against pollen grains of the locule. Further observations with transmission electron microscopy revealed that the mitochondria in CMS 21A tapetum were highly vacuolated, and there was no accumulation of sporopollenin on the surface of CMS 21A pollen, suggesting a close relationship between early degeneration of tapetum and CMS.
Search for partial resistance against Puccinia hordei in barley landraces from the Fertile Crescent
Authors: Shtaya M. J. Y. , Sillero J. C. , Rubiales D.
Published: July 2006

A collection of 111 barley landraces from the Fertile Crescent was screened for resistance to barley leaf rust in the field and under controlled conditions. Large variation was observed for disease severity under field conditions. Accessions with high resistance because of hypersensitivity were identified. Also segregation was observed in some accessions, with individual plants showing hypersensitive reactions (IT ≤ 6). Partial resistance due to a reduction of infection in spite of a compatible infection was commonly found (19%). Resistance of 12 accessions selected for their low disease severity and high IT, was shown to be due to a prolonged latency period and increased percentage of early aborted colonies not associated with host cell necrosis. A high correlation was observed between the microscopic and macroscopic components of partial resistance.
Advantages of endoscopic submucosal dissection over conventional endoscopic mucosal resection
Authors: Shimura Takaya , Sasaki Makoto , Kataoka Hiromi , Tanida Satoshi , Oshima Tadayuki , Ogasawara Naotaka , Wada Tsuneya , Kubota Eiji , Yamada Tomonori , Mori Yoshinori , Fujita Fumitaka , Nakao Haruhisa , Ohara Hirotaka , Inukai Masami , Kasugai Kunio , Joh Takashi
Published: July 2006

Background:  Endoscopic mucosal resection is an established method for treating intramucosal gastric neoplasms. Conventional endoscopic mucosal resection has predominantly been performed using strip biopsy, but local recurrence sometimes occurs due to such piecemeal resection. Endoscopic submucosal dissection has recently been performed in Japan using new devices such as an insulation‐tip diathermic knife. The efficacy and problems associated with endoscopic submucosal dissection were evaluated by comparison with conventional endoscopic mucosal resection.

Methods:  Treatment consisted of conventional endoscopic mucosal resection for 48 lesions from January 1999 to October 2002, and endoscopic submucosal dissection for 59 lesions from November 2002 to June 2005. Endoscopic submucosal dissection was performed using an insulation‐tip diathermic knife and flex and hook knives, as appropriate.

Results:  For lesions ≥11 mm in size, en bloc resection rates were significantly higher with endoscopic submucosal dissection than with conventional endoscopic mucosal resection, but treatment time was significantly longer. En bloc resection rates were higher with endoscopic submucosal dissection than with conventional endoscopic mucosal resection in all areas. Treatment of lesions in the upper one‐third of the stomach took a long time using endoscopic submucosal dissection, and intraoperative bleeding was frequent. However, en bloc resection rates and intraoperative bleeding with endoscopic submucosal dissection were improved using various knives.

Conclusions:  Endoscopic submucosal dissection can take a long time, but is superior to conventional endoscopic mucosal resection for treating intramucosal gastric neoplasms.
Association of pre‐S deletion mutant of hepatitis B virus with risk of hepatocellular carcinoma
Authors: Lin Chih‐Lin , Liu Chen‐Hua , Chen Wendy , Huang Wen‐Ling , Chen Pei‐Jer , Lai Ming‐Yang , Chen Ding‐Shinn , Kao Jia‐Horng
Published: July 2006

Background:  Pre‐S deletion mutant of hepatitis B virus (HBV) affects the expression of middle and small surface proteins, resulting in intracellular accumulation of large surface protein. The correlation between pre‐S deletion mutant and risk of hepatocellular carcinoma (HCC) in hepatitis B virus carriers remains unclear.

Methods:  Using molecular assays, pre‐S deletion mutant of HBV were determined in 266 patients with chronic HBV genotype B or C infection. They included 202 asymptomatic carriers and 64 HCC patients.

Results:  The overall prevalence of pre‐S deletion mutant was 16.5%. Hepatocellular carcinoma (odds ratio [OR], 3.23; 95% confidence interval [CI], 1.23–8.48, P = 0.02) and genotype C (OR, 3.19; 95%CI, 1.54–6.62, P = 0.002) were independently associated with the presence of pre‐S deletion mutant. The prevalence of pre‐S deletion mutant was comparable between HCC patients with genotype B and C infection. Nevertheless, in asymptomatic carriers, patients with genotype C infection were significantly associated with the presence of pre‐S deletion mutant compared to those with genotype B infection (20.8% vs 7.2%, P = 0.007). Compared with age‐ and genotype B‐matched asymptomatic carriers, young HCC patients (<50 years of age) had a significantly higher frequency of pre‐S deletion (3.4% vs 20%, P = 0.04).

Conclusions:  Pre‐S deletion mutant is more frequent in HBV carriers with genotype C infection, and those with pre‐S deletion mutant may be associated with the development of HCC, irrespective of HBV genotype.
Abdominal obesity is an independent risk factor for erosive esophagitis in a Korean population
Authors: Kang Mun Su , Park Dong Il , Oh Se Yong , Yoo Tae Woo , Ryu Seung Ho , Park Jung Ho , Kim Hong Joo , Cho Yong Kyun , Sohn Chong Il , Jeon Woo Kyu , Kim Byung Ik
Published: July 2006

Background:  The relationship between obesity and gastroesophageal reflux disease (GERD) is controversial. The aim of the present study was to investigate the potential roles of body mass index (BMI) and waist circumference on GERD in a Korean population.

Methods:  A total of 2457 subjects who visited the Kangbuk Samsung Hospital medical screening center for esophagogastroduodenoscopy from September 2004 to April 2005 were enrolled. All participants were given a questionnaire to determine reflux symptoms. Abdominal obesity was defined as a waist circumference ≥80 cm in women and ≥90 cm in men.

Results:  The proportion of subjects in each BMI group was 68.9%, 28.7% and 2.4% for BMI <25, 25–30 and >30, respectively. The prevalence of abdominal obesity was 24.2%. The prevalence of reflux symptoms was 8.2%. Neither BMI nor abdominal obesity was significantly associated with reflux symptoms after adjustment. The prevalence of erosive esophagitis was 6.6%. There was a clear dose–response relationship between prevalence of erosive esophagitis and BMI (5.6%, 8.1% and 15.5% for BMI <25, 25–30 and >30, respectively, P = 0.002). Abdominal obesity was also associated with erosive esophagitis (odds ratio, 2.3; 95% confidence interval, 1.6–3.1). However, only the association between abdominal obesity and erosive esophagitis remained strong after adjustments.

Conclusions:  Abdominal obesity rather than BMI is an independent risk factor for erosive esophagitis in the Korean population.
Technical feasibility of endoscopic submucosal dissection for gastric neoplasms in the elderly Japanese population
Authors: Kakushima Naomi , Fujishiro Mitsuhiro , Kodashima Shinya , Muraki Yosuke , Tateishi Ayako , Yahagi Naohisa , Omata Masao
Published: July 2006

Background and Aim:  Endoscopic submucosal dissection (ESD) is gaining acceptance among endoscopists for its efficacy, especially in Japan. Elderly patients often have operative risk due to comorbid diseases, and the feasibility of this treatment for such patients should be investigated. The aim of this study is to evaluate the efficacy and safety of ESD in elderly patients.

Methods:  Among 308 gastric neoplasms treated by ESD from 2000 to 2004 in one hospital, 49 lesions were discovered in 42 elderly patients who were 75 years of age or older. Indication criteria for ESD were gastric neoplasms with no apparent massive submucosal invasion diagnosed by endoscopy. The en bloc plus R0 resection rate and complications were assessed in comparison with younger patients.

Results:  The average age of the patients was 78.9 years (range 75–88 years). Of these patients, 24 (57%) had comorbid diseases. The complete en bloc plus R0 resection rate was 96% (47/49). Postoperative bleeding requiring emergency endoscopy occurred in three patients (7%). Perforation during ESD occurred in one patient (2%), and was immediately closed with endoclips and managed by conservative medical treatment. The en bloc plus R0 resection rate and complication rate in elderly patients were not significantly different from those of younger patients.

Conclusions:  These results indicate that ESD could be a safe and reliable treatment for gastric neoplasms in elderly patients.
Functional screening of traditional antidepressants with primary cortical neuronal networks grown on multielectrode neurochips
Authors: Gramowski Alexandra , Jügelt Konstantin , Stüwe Simone , Schulze Roland , McGregor Gerard P. , Wartenberg‐Demand Andrea , Loock Jan , Schröder Olaf , Weiss Dieter G.
Published: July 2006

We optimized the novel technique of multielectrode neurochip recordings for the rapid and efficient screening of neuroactivity. Changes in the spontaneous activity of cultured networks of primary cortical neurons were quantified to evaluate the action of drugs on the firing dynamics of complex network activity. The multiparametric assessment of electrical activity changes caused by psychoactive herbal extracts from Hypericum, Passiflora and Valeriana, and various combinations thereof revealed a receptor‐specific and concentration‐dependent inhibition of the firing patterns. The spike and burst rates showed significant substance‐dependent effects and significant differences in potency. The effects of specific receptor blockades on the inhibitory responses provided evidence that the herbal extracts act on gamma‐amino butyric acid (GABA) and serotonin (5‐HT) receptors, which are recognized targets of pharmacological antidepressant treatment. A biphasic effect, serotonergic stimulation of activity at low concentrations that is overridden by GABAergic inhibition at higher concentrations, is apparent with Hypericum alone and the triple combination of the extracts. The more potent neuroactivity of the triple combination compared to Hypericum alone and the additive effect of Passiflora and Valeriana suggest a synergy between constituent herbal extracts. The extracts and their combinations affected the set of derived activity parameters in a concomitant manner suggesting that all three constituent extracts and their combinations have largely similar modes of action. This study also demonstrates the sensitivity, selectivity and robustness of neurochip recordings for high content screening of complex mixtures of neuroactive substances and for providing multiparametric information on neuronal activity changes to assess the therapeutic potential of psychoactive substances.
Inhibition of constitutive inward rectifier currents in cerebellar granule cells by pharmacological and synaptic activation of GABAB receptors
Authors: Rossi Paola , Mapelli Lisa , Roggeri Leda , Gall David , De Kerchove d'Exaerde Alban , Schiffmann Serge N. , Taglietti Vanni , D'Angelo Egidio
Published: July 2006

γ‐Aminobutyric acid (GABA)B receptors are known to enhance activation of Kir3 channels generating G‐protein‐dependent inward rectifier K+‐currents (GIRK). In some neurons, GABAB receptors either cause a tonic GIRK activation or generate a late K+‐dependent inhibitory postsynaptic current component. However, other neurons express Kir2 channels, which generate a constitutive inward rectifier K+‐current (CIRK) without requiring G‐protein activation. The functional coupling of CIRK with GABAB receptors remained unexplored so far. About 50% of rat cerebellar granule cells in the internal granular layer of P19–26 rats showed a sizeable CIRK current. Here, we have investigated CIRK current regulation by GABAB receptors in cerebellar granule cells, which undergo GABAergic inhibition through Golgi cells. By using patch‐clamp recording techniques and single‐cell reverse transcriptase‐polymerase chain reaction in acute cerebellar slices, we show that granule cells co‐express Kir2 channels and GABAB receptors. CIRK current biophysical properties were compatible with Kir2 but not Kir3 channels, and could be inhibited by the GABAB receptor agonist baclofen. The action of baclofen was prevented by the GABAB receptor blocker CGP35348, involved a pertussis toxin‐insensitive G‐protein‐mediated pathway, and required protein phosphatases inhibited by okadaic acid. GABAB receptor‐dependent CIRK current inhibition could also be induced by repetitive GABAergic transmission at frequencies higher than the basal autorhythmic discharge of Golgi cells. These results suggest therefore that GABAB receptors can exert an inhibitory control over CIRK currents mediated by Kir2 channels. CIRK inhibition was associated with an increased input resistance around rest and caused a ∼ 5 mV membrane depolarization. The pro‐excitatory action of these effects at an inhibitory synapse may have an homeostatic role re‐establishing granule cell readiness under conditions of strong inhibition.
Postnatal development of the murine cerebellar cortex: formation and early dispersal of basket, stellate and Golgi neurons
Authors: Weisheit Gunnar , Gliem Michael , Endl Elmar , Pfeffer Peter L. , Busslinger Meinrad , Schilling Karl
Published: July 2006

The cerebellar cortex consists of a small set of neuronal cell types interconnected in a highly stereotyped way. While the development of cerebellar cortical projection neurons, i.e. Purkinje cells, and that of granule cells has been elucidated in considerable detail, that of cerebellar cortical inhibitory interneurons is still rather fragmentarily understood. Here, we use mice expressing green fluorescent protein (GFP) from the Pax2 locus to analyse the ontogenesis of these cells. Numbers of Pax2‐positive inhibitory interneuronal precursors increase following a classical sigmoidal growth curve to yield a total of some 905.000 ± 77.000 cells. Maximal cell increase occurs at about postnatal day (P)5.4, and some 75% of all inhibitory interneurons are generated prior to P7. Conjoint analysis of the developmental accruement of Pax2‐GFP‐positive cells and their cell cycle distribution reveals that, at least at P0 and P3, the numerical increase of these cells results primarily from proliferation of a Pax2‐negative precursor population and suggests that Pax2 expression begins at or around the final mitosis. Following their terminal mitosis, inhibitory cerebellar cortical interneurons go through a protracted quiescent phase in which they maintain expression of the cell cycle marker Ki‐67. During this phase, they translocate into the nascent molecular layer, where they stall next to premigratory granule cell precursors without penetrating this population of cells. These observations provide a quantitative description of cerebellar cortical inhibitory interneuron genesis and early differentiation, and define Pax2 as a marker expressed in basket and stellate cells, from around their final mitosis to their incipient histogenetic integration.
Early life modulators and predictors of adult synaptic plasticity
Authors: Akers Katherine G. , Nakazawa Masato , Romeo Russell D. , Connor John A. , McEwen Bruce S. , Tang Akaysha C.
Published: July 2006

Early life experience can induce long‐lasting changes in brain and behaviour that are opposite in direction, such as enhancement or impairment in regulation of stress response, structural and functional integrity of the hippocampus, and learning and memory. To explore how multiple early life events jointly determine developmental outcome, we investigated the combined effects of neonatal trauma (anoxia on postnatal day 1, P1) and neonatal novelty exposure (P2–21) on adult social recognition memory (3 months of age) and synaptic plasticity in the CA1 of the rat hippocampus (4.5–8 months of age). While neonatal anoxia selectively reduced post‐tetanic potentiation (PTP), neonatal novel exposure selectively increased long‐term potentiation (LTP). No interaction between anoxia and novelty exposure was found on either PTP or LTP. These findings suggest that the two contrasting neonatal events have selective and distinct effects on two different forms of synaptic plasticity. At the level of behaviour, the effect of novelty exposure on LTP was associated with increased social memory, and the effect of anoxia on PTP was not accompanied by changes in social memory. Such a finding suggests a bias toward the involvement of LTP over PTP in social memory. Finally, we report a surprising finding that an early behavioural measure of emotional response to a novel environment obtained at 25 days of age can predict adult LTP measured several months later. Therefore, individual differences in emotional responses present during the juvenile stage may contribute to adult individual differences in cellular mechanisms that underlie learning and memory.
Cell culture models to investigate the selective vulnerability of motoneuronal mitochondria to familial ALS‐linked G93ASOD1
Authors: Raimondi Andrea , Mangolini Alessandra , Rizzardini Milena , Tartari Silvia , Massari Silvia , Bendotti Caterina , Francolini Maura , Borgese Nica , Cantoni Lavinia , Pietrini Grazia
Published: July 2006

Mitochondrial damage induced by superoxide dismutase (SOD1) mutants has been proposed to have a causative role in the selective degeneration of motoneurons in amyotrophic lateral sclerosis (ALS). In order to investigate the basis of the tissue specificity of mutant SOD1 we compared the effect of the continuous expression of wild‐type or mutant (G93A) human SOD1 on mitochondrial morphology in the NSC‐34 motoneuronal‐like, the N18TG2 neuroblastoma and the non‐neuronal Madin–Darby Canine Kidney (MDCK) cell lines. Morphological alterations of mitochondria were observed in NSC‐34 expressing the G93A mutant (NSC‐G93A) but not the wild‐type SOD1, whereas a ten‐fold greater level of total expression of the mutant had no effect on mitochondria of non‐motoneuronal cell lines. Fragmented network, swelling and cristae remodelling but not vacuolization of mitochondria or other intracellular organelles were observed only in NSC‐G93A cells. The mitochondrial alterations were not explained by a preferential localization of the mutant within NSC‐G93A mitochondria, as a higher amount of the mutant SOD1 was found in mitochondria of MDCK‐G93A cells. Our results suggest that mitochondrial vulnerability of motoneurons to G93ASOD1 is recapitulated in NSC‐34 cells, and that peculiar features in network dynamics may account for the selective alterations of motoneuronal mitochondria.
Limb (hand vs. foot) and response conflict have similar effects on event‐related potentials (ERPs) recorded during motor imagery and overt execution
Authors: Carrillo‐de‐la‐Peña M. T. , Lastra‐Barreira C. , Galdo‐Álvarez S.
Published: July 2006

Although there is substantial evidence that motor execution (M‐Ex) and motor imagery (M‐Im) share a common neural substrate, the role of the primary motor cortex (M1) during imagery is still a matter of debate. The present ERP study tries to clarify the functional similarity between the two processes in respect of (i) the engagement of the corresponding somatotopic M1 areas during execution and imagery of hand vs. foot movements; and (ii) the effect of conflicting information on response preparation. To this end, we recorded ERPs from 28 electrode sites in 19 participants while they performed a conflict task with congruent (target and flanker arrowheads pointing in the same direction) and incongruent (target pointing in the opposite direction to the flanker arrowheads) trials. We obtained the lateralized readiness potential (LRP), a component generated in M1, while subjects physically executed or mentally simulated the task. As expected by the somatotopic organization of M1, the LRP was of opposite polarity when foot, rather than hand, movements were prepared. The inversion of polarity also occurred during M‐Im, a result that strongly argues in favour of the participation of M1 in motor imagery. In incongruent trials, longer LRP latencies, a premature preparation of the incorrect response (positive deflection in LRP waveform) and a fronto‐central N2 component associated with response conflict appeared during both M‐Ex and M‐Im. Altogether, the results support the functional equivalence of the two processes and give support to the clinical use of M‐Im for the improvement and recovery of motor functions.
Apoptosis in the rat basal forebrain during development and following lesions of connections
Authors: Sophou Stavroula , Dori Ioanna , Antonopoulos John , Parnavelas John G. , Dinopoulos Athanasios
Published: July 2006

Evidence suggests that neurotrophins are essential for the survival and phenotypic maintenance of cholinergic basal forebrain (BF) neurons. We evaluated the pattern of programmed cell death in the BF of the rat during development and after ablations of the cerebral cortex, a major target area and source of neurotrophins for BF neurons. We identified dying cells using the TUNEL (terminal deoxynucleotidyl‐transferase‐mediated dUTP‐biotin nick end labelling) method and confirmed their apoptotic morphology with electron microscopy. Moreover, we demonstrated the expression of the apoptotic marker active caspase‐3 in cells with features of apoptosis. TUNEL+ cells were present in the developing BF during the first two postnatal weeks. Their frequency peaked at postnatal day (P)1 and at P5. TUNEL used in conjunction with immunofluorescence for neuronal nuclear protein (NeuN) showed that, at both peak stages, the majority of apoptotic cells were neurons. Extensive lesions of the cerebral cortex at different ages (P0, P7 and P14) did not induce significant changes in the frequency of apoptotic BF neurons. However, they resulted in alterations in the morphological phenotype of choline acetyltransferase (ChAT)‐immunoreactive neurons in the BF, and a reduction in their number which was inversely proportional to the age at which the lesions were performed. We suggest that: (i) apoptosis is temporally coordinated with the morphological and neurochemical differentiation of BF neurons and the establishment of connections with their target areas; and (ii) cortical ablations do not affect the survival of BF neurons, but they influence the phenotype of cholinergic BF neurons.
Inhibition of BKCa channel activity by association with calcineurin in rat brain
Authors: Loane David J. , Hicks Gareth A. , Perrino Brian A. , Marrion Neil V.
Published: July 2006

Large conductance calcium‐activated potassium (BKCa) channels are regulated by a number of different protein kinases and phosphatases. The close association of enzymes and channel have been shown to underlie many examples of modulation. However, only the association of protein kinase A with the BKCa channel has been detailed [Tian et al. (2003)J. Biol. Chem., 278, 8669–8677]. We have found using reciprocal immunoprecipitations that the BKCa channel associates with the calcium/calmodulin‐dependent phosphatase calcineurin, in Wistar rat brain. A HA‐tagged construct of the carboxyl terminus of rSlo27, a variant of the BKCa channel that is abundant in the hippocampus [Ha et al. (2000)Eur. J. Biochem., 267, 910–9218], was found to associate only with the B subunit of calcineurin. This data suggests that the majority of the interaction of the BKCa channel with calcineurin is mediated by the B subunit of the phosphatase. This was confirmed by using glutathione‐S‐transferase (GST) fusion proteins of the linker regions between the S7–S10 hydrophobic domains in the carboxyl terminus of rSlo27, where only the B subunit of calcineurin interacted with regions between S7 and S9 of the channel. Addition of a constitutively active calcineurin (CaN420) to inside‐out membrane patches excised from cultured hippocampal neurons resulted in a dramatic reduction in BKCa channel open probability, with only very short‐duration events being apparent. These data suggest that BKCa channel activity is inhibited by calcineurin, an effect mediated by the association of the calcineurin B subunit with the carboxyl terminus of the channel.
Immunolocalization of BK channels in hippocampal pyramidal neurons
Authors: Sailer Claudia A. , Kaufmann Walter A. , Kogler Michaela , Chen Lie , Sausbier Ulrike , Ottersen Ole Petter , Ruth Peter , Shipston Michael J. , Knaus Hans‐Günther
Published: July 2006

Neurons are highly specialized cells in which the integration and processing of electrical signals critically depends on the precise localization of ion channels. For large‐conductance Ca2+‐ activated K+ (BK) channels, targeting to presynaptic membranes in hippocampal pyramidal cells was reported; however, functional evidence also suggests a somatodendritic localization. Therefore we re‐examined the subcellular distribution of BK channels in mouse hippocampus using a panel of independent antibodies in a combined approach of conventional immunocytochemistry on cultured neurons, pre‐ and postembedding electron microscopy and immunoprecipitation. In cultured murine hippocampal neurons, the colocalization of BK channels with both pre‐ and postsynaptic marker proteins was observed. Electron microscopy confirmed targeting of BK channels to axonal as well as dendritic membranes of glutamatergic synapses in hippocampus. A postsynaptic localization of BK channels was also supported by the finding that the channel coimmunoprecipitated with PSD95, a protein solely expressed in the postsynaptic compartment. These results thus demonstrate that BK channels reside in both post‐ and presynaptic compartments of hippocampal pyramidal neurons.
Partial inhibition of PP1 alters bidirectional synaptic plasticity in the hippocampus
Authors: Jouvenceau Anne , Hédou Gael , Potier Brigitte , Kollen Mélanie , Dutar Patrick , Mansuy Isabelle M.
Published: July 2006

Synaptic plasticity is an important cellular mechanism that underlies memory formation. In brain areas involved in memory such as the hippocampus, long‐term synaptic plasticity is bidirectional. Major forms of bidirectional plasticity encompass long‐term potentiation (LTP), LTP reversal (depotentiation) and long‐term depression (LTD). Protein kinases and protein phosphatases are important players in the induction of both LTP and LTD, and the serine/threonine protein phosphatase‐1 (PP1), in particular, has emerged as a key phosphatase in these processes. The goal of the present study was to assess the contribution of PP1 to bidirectional plasticity and examine the impact of a partial inhibition of PP1 on LTP, LTD and depotentiation in the mouse hippocampus. For this, we used transgenic mice expressing an active PP1 inhibitor (I‐1*) inducibly in forebrain neurons. We show that partial inhibition of PP1 by I‐1* expression alters the properties of bidirectional plasticity by inducing a shift of synaptic responses towards potentiation. At low‐frequency stimulation, PP1 inhibition decreases LTD in a frequency‐dependent fashion. It favours potentiation over depression at intermediate frequencies and increases LTP at high frequency. Consistently, it also impairs depotentiation. These results indicate that the requirement of bidirectional plasticity for PP1 is frequency‐dependent and that a broad range of plasticity is negatively constrained by PP1, a feature that may correlate with the property of PP1 to constrain learning efficacy and promote forgetting.
A novel type of cold‐sensitive neuron in rat dorsal root ganglia with rapid adaptation to cooling stimuli
Authors: Babes Alexandru , Zorzon Daniel , Reid Gordon
Published: July 2006

Cold sensing in mammals is heterogeneous and more than one type of receptor molecule is likely to be involved in the transduction process. Most features of innocuous cold receptors have been explained by TRPM8, the cold and menthol receptor, but their fast adaptation to cooling has not yet been reproduced in cellular systems. In this study we have used a newly developed system for applying fast thermal stimuli to dissociated dorsal root ganglia (DRG) neurons from young rats (150–200 g) in primary culture. We describe a novel type of cold‐sensitive rat DRG neuron with rapid adaptation to cooling. These cells (4.3% of the total DRG population) do not express either TRPM8 or the other cold‐activated TRP channel, TRPA1, and the epithelial sodium channel (ENaC) is not involved in their transduction. Increases in intracellular calcium induced by cooling in rapidly adapting neurons are caused by calcium entry. These neurons express a large and rapidly adapting cold‐induced inward current with a time constant of adaptation in the seconds range, and may correspond to the rapidly adapting cold receptors described in vivo.
Attenuating corticosterone levels on the day of memory assessment prevents chronic stress‐induced impairments in spatial memory
Authors: Wright Ryan L. , Lightner Elizabeth N. , Harman James S. , Meijer Onno C. , Conrad Cheryl D.
Published: July 2006

This study investigated whether chronic stress‐induced spatial memory deficits were caused by changes in the hypothalamic‐pituitary‐adrenal axis, such as corticosterone (CORT) elevations on the day of memory assessment, rather than the consequence of structural changes in the hippocampus. Male Sprague–Dawley rats were restrained for 6 h/day/21 days, and spatial memory was assessed on the Y‐maze on day 22. Ninety minutes before training, rats received a subcutaneous injection of vehicle or metyrapone, a CORT synthesis inhibitor, and then spatial memory was determined 4‐h later. The highest dose of metyrapone (75 mg/kg, s.c.) was most effective at preventing stress‐induced spatial memory deficits. Chronic stress increased total CORT levels following Y‐maze exposure, while acute metyrapone treatment dose‐dependently attenuated total and free (unbound) CORT levels in both stress and control conditions. Blood samples taken from a separate subset of chronically stressed rats showed that baseline CORT levels were similar across the restraint period. Finally, chronic stress down‐regulated glucocorticoid, but not mineralocorticoid, receptor mRNA expression within the hippocampus (dentate gyrus, CA1, CA2, CA3). These findings suggest that chronic stress‐induced spatial memory deficits may be mediated by hypothalamic‐pituitary‐adrenal axis dysregulation. Specifically, CORT elevations and reductions in hippocampal glucocorticoid receptor expression, at the time of behavioural assessment may be involved, as opposed to a direct effect that is solely dependent upon hippocampal structural changes. These results have significance for treating cognitive decline in conditions associated with elevated glucocorticoids that include subpopulations in ageing, depression, Cushing's disease and Alzheimer's disease.
A context‐specific single contingent‐reinforcing stimulus boosts intermediate‐term memory into long‐term memory
Authors: Parvez Kashif , Moisseev Victor , Lukowiak Ken
Published: July 2006

Following operant conditioning of aerial respiration in Lymnaea, memory forms. Depending on the training procedure either intermediate memory (ITM, < 3 h) or long‐term memory (LTM, > 6 h) results. ITM is dependent on de novo protein synthesis whilst LTM is dependent on both transcription and de novo protein synthesis. LTM formation requires the soma of RPeD1 (one of the central pattern generator neurons) to be present. Following activation of a memory, it re‐enters a labile state and undergoes a reconsolidation process to restabilize it. During reconsolidation, memory may be updated and/or changed. We add here another consequence of memory reactivation: a single contingent‐reinforcing stimulus (SCRS), given in the same context as previous ITM training, boosts a residual memory trace to LTM. Separate cohorts of snails first received the ITM training procedure. In the cohort that received the SCRS 24 h after the last ITM training session, LTM was observed on the following day. LTM was not observed in cohorts that were: (i) given a single noncontingent stimulus; (ii) given the SCRS in a context other than the ITM training; (iii) given a 48‐h gap between the last ITM training session and the context‐specific SCRS; (iv) cooled immediately after the last ITM training session; (v) cooled immediately after the delivery of the context‐specific SCRS; (vi) had the soma of RPeD1 ablated before the presentation of the context‐specific SCRS; (vii) received a yoked control procedure. These data lead us to conclude that the context‐specific SCRS reactivates a residual molecular memory trace in RPeD1 and boosts it into becoming the substrate for LTM.
Cyanobacterial assimilatory nitrate reductase gene diversity in coastal and oligotrophic marine environments
Authors: Jenkins Bethany D. , Zehr Jonathan P. , Gibson Angela , Campbell Lisa
Published: July 2006

Cyanobacteria are important primary producers in many marine ecosystems and their abundances and growth rates depend on their ability to assimilate various nitrogen sources. To examine the diversity of nitrate‐utilizing marine cyanobacteria, we developed PCR primers specific for cyanobacterial assimilatory nitrate reductase (narB) genes. We obtained amplification products from diverse strains of cultivated cyanobacteria and from several marine environments. Phylogenetic trees constructed with the narB gene are congruent with those based on ribosomal RNA genes and RNA polymerase genes. Analysis of sequence library data from coastal and oligotrophic marine environments shows distinct groups of Synechococcus sp. in each environment; some of which are represented by sequences from cultivated organisms and others that are unrelated to known sequences and likely represent novel phylogenetic groups. We observed spatial differences in the distribution of sequences between two sites in Monterey Bay and differences in the vertical distribution of sequence types at the Hawai’i Ocean Time‐series Station ALOHA, suggesting that nitrogen assimilation in Synechococcus living in different ecological niches can be followed with the nitrate reductase gene.
Presence of Hydrogenophilus thermoluteolus DNA in accretion ice in the subglacial Lake Vostok, Antarctica, assessed using rrs, cbb and hox
Authors: Lavire Céline , Normand Philippe , Alekhina Irina , Bulat Serguey , Prieur Daniel , Birrien Jean‐Louis , Fournier Pascale , Hänni Catherine , Petit Jean‐Robert
Published: July 2006

The 3561 m Vostok ice core sample originating from the subglacial Lake Vostok accretion (frozen lake water) ice with sediment inclusions was thoroughly studied by various means to confirm the presence of the thermophile bacterium Hydrogenophilus thermoluteolus reported earlier in the 3607 m accretion ice sample. PCR and molecular‐phylogenetic analyses performed in two independent laboratories were made using different 16S rRNA gene (rrs) targeted primers. As a result, rrs‐targeted PCR permitted to recover several very closely related clones with a small genetic distance to Hydrogenophilus thermoluteolus (< 1%). In addition, RubisCO (cbbL or rbcL) and NiFe‐Hydrogenase (hoxV or hupL) targeted PCR have also allowed to recover sequences highly related to Hydrogenophilus thermoluteolus. All these results point to the presence of thermophilic chemoautotrophic microorganisms in Lake Vostok accretion ice. They presumably originate from deep faults in the bedrock cavity containing the lake in which episodes of seismotectonic activity would release debris along with microbial cells.
OxyR regulated the expression of two major catalases, KatA and KatB, along with peroxiredoxin, AhpC in Pseudomonas putida
Authors: Hishinuma Sota , Yuki Masahiro , Fujimura Makoto , Fukumori Fumiyasu
Published: July 2006

OxyR is known to activate/repress the expression of the oxyR regulon, which consists of several genes, which play important antioxidant role in Escherichia coli. To elucidate the role of OxyR in Pseudomonas putida KT2442, the oxyR1 mutation that caused the upregulation of ahpC in a toluene‐resistant variant strain was introduced, because no null mutants in oxyR were isolated. This mutation was shown to cause the accumulation of a catalase (KatA) along with AhpC throughout the growth, and of a RpoS‐dependent catalase/peroxidase (KatB) in the stationary phase. Following the identification of the transcription start site of two catalase genes, sequences similar to those involved in the proposed OxyR binding for E. coli were found upstream from each of the promoter regions of katA and katB, as well as ahpC. Purified OxyR was shown to bind to these sequences, under both reduced and oxidized states. Moreover, the oxyR1 mutation increased the transcription levels of these genes. These results are consistent with the conclusion, distinct from those observed in an opportunistic pathogen Pseudomonas aeruginosa, that OxyR controlled expression of all the principal peroxide‐degrading enzymes in P. putida. The mutation did not cause any notable changes in the transcriptional levels of several antioxidant genes, including those of glutathione reductase, glutaredoxins and thioredoxins, which would involve maintenance of the cellular thiol‐disulfide balance, suggesting that the transcriptional regulation of these antioxidant genes should be different from that of katA, katB and ahpC in P. putida.
Cultivation‐independent analysis of Pseudomonas species in soil and in the rhizosphere of field‐grown Verticillium dahliae host plants
Authors: Costa Rodrigo , Salles Joana Falcão , Berg Gabriele , Smalla Kornelia
Published: July 2006

Despite their importance for rhizosphere functioning, rhizobacterial Pseudomonas spp. have been mainly studied in a cultivation‐based manner. In this study a cultivation‐independent method was used to determine to what extent the factors plant species, sampling site and year‐to‐year variation influence Pseudomonas community structure in bulk soil and in the rhizosphere of two Verticillium dahliae host plants, oilseed rape and strawberry. Community DNA was extracted from bulk and rhizosphere soil samples of flowering plants collected at three different sites in Germany in two consecutive years. Pseudomonas community structure and diversity were assessed using a polymerase chain reaction denaturing gradient gel electrophoresis (PCR‐DGGE) system to fingerprint Pseudomonas‐specific 16S rRNA gene fragments amplified from community DNA. Dominant and differentiating DGGE bands were excised from the gels, cloned and sequenced. The factors sampling site, plant species and year‐to‐year variation were shown to significantly influence the community structure of Pseudomonas in rhizosphere soils. The composition of Pseudomonas 16S rRNA gene fragments in the rhizosphere differed from that in the adjacent bulk soil and the rhizosphere effect tended to be plant‐specific. The clone sequences of most dominant bands analysed belonged to the Pseudomonas fluorescens lineage and showed closest similarity to culturable Pseudomonas known for displaying antifungal properties. This report provides a better understanding of how different factors drive Pseudomonas community structure and diversity in bulk and rhizosphere soils.
‘Pitted but not pitied’ or, does smallpox make you small?1
Authors: OXLEY DEBORAH
Published: July 2006

This article examines three propositions put by Leunig and Voth: that smallpox reduced stature irrespective of location, that stunting was most apparent among adolescents, and that these relationships were obscured in my earlier work by small sample size. It tests these claims by re‐examining the original data—including the neglected Wandsworth data set—and questioning the meaning of the chosen method of graphical representation. Furthermore, and most fundamentally, the relationship between smallpox and stunting is advanced by adding new data on a further 34,310 prisoners. Using considerably larger data sets with many more juveniles, and refined definitions of rural and urban locations, this article confirms that the ‘smallpox effect’ varied by location, age, gender, and time period. That the relationship between smallpox and stunting was mediated through place and time suggests the role played by evolving urban conditions. The article offers a warning on the dangers of aggregating data without paying heed to important composition effects, and it argues that size does matter: the size of the smallpox effect, population size, sample size, and the size of the p‐statistic. The reply concludes by again questioning the likely causes of stunting in the world’s first great metropolis, London, arguing for the importance of examining chronic illness as a source of ongoing nutritional insult.
Advice Alone Vs. Structured Detoxification Programmes for Medication Overuse Headache: A Prospective, Randomized, Open-Label Trial in Transformed Migraine Patients With Low Medical Needs
Authors: Rossi P , Lorenzo C Di , Faroni J , Cesarino F , Nappi G
Published: July 2006

The aim of this study was to compare the effectiveness of strong advice to withdraw the overused medication with the effectiveness of two structured pharmacological detoxification strategies in a cohort of patients diagnosed with probable migraine overuse headache (MOH) plus migraine and presenting low medical needs. One hundred and twenty patients participated in the study. Exclusion criteria included: previous detoxification treatments, coexistent medical or psychiatric illnesses and overuse of agents containing opioids, benzodiazepines and barbiturates. Group A received only intensive advice to withdraw the overused medication. Group B underwent a standard out-patient detoxification programme (advice + prednisone + preventive treatment). Group C underwent a standard inpatient withdrawal programme (as in group B + fluid replacement and antiemetics). Withdrawal therapy was considered successful if, after 2 months, the patient had reverted to an episodic pattern of headache and to an intake of symptomatic medication on fewer than 10 days/month. We were able to detoxify 75.4± of the whole cohort, 77.5± of patients in group A, 71.7± of patients in group B and 76.9± of those in group C ( P > 0.05). In patients with migraine plus MOH and low medical needs, effective drug withdrawal may be obtained through the imparting of advice alone.
Central Sensitization of The Trigeminal and Somatic Nociceptive Systems in Medication Overuse Headache Mainly Involves Cerebral Supraspinal Structures
Authors: Ayzenberg I , Obermann M , Nyhuis P , Gastpar M , Limmroth V , Diener HC , Kaube H , Katsarava Z
Published: July 2006

Trigeminal and somatic nociceptive systems were studied in controls ( n = 15), episodic migraine ( n = 16), analgesics ( n = 14) and triptan-induced medication overuse headache (MOH) ( n = 15) before and after withdrawal. Patients with MOH and comorbid depressive symptoms and depression without headache were studied to investigate the influence of depression. Trigeminal nociception was studied by simultaneous registration of pain-related cortical potentials (PREP) and nociceptive blink reflex (nBR) following nociceptive-specific electrical stimulation of the forehead. Somatic nociception was evaluated using PREP of upper limbs. We found facilitation of both trigeminal and somatic PREP but not of nBR in MOH, which normalized after withdrawal. No differences were found comparing analgesics vs. triptan MOH. No differences were observed between controls and patients with episodic migraine and depression without headache. A transient facilitation was found of trigeminal and somatic nociceptive systems in MOH, which was more pronounced on a supraspinal level.