bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cathepsin D Activity in the Vitellogenesis of Xenopus laevis
Authors: Yoshizaki Norio , Yonezawa Satoshi 
Published: January 2005

An ovarian extract of Xenopus laevis exhibited in SDS‐PAGE analyses an activity cleaving vitellogenin to lipovitellins under mildly acidic conditions. This activity was pepstatin‐sensitive and inhibited by monospecific anti‐rat liver cathepsin D antibody and thus identified as cathepsin D. Immunoblot analysis showed that two proteins of 43 kDa and 36 kDa immunoreacted with the antibody.Immunocytochemical staining revealed that the enzyme was located in the cortical cytoplasm of stage I and II oocytes and in small yolk platelets and nascent forms of large yolk platelets in the cortical cytoplasm of stage III oocytes. In stage IV and V oocytes, small yolk platelets retained the immuno‐staining but large yolk platelets decreased it. No immuno‐positive signals were observed in oocytes at stage VI. When examined by immunoelectron microscopy, gold particles indicated that cathepsin D was located on dense lamellar bodies in the cortical cytoplasm of stage I and II oocytes. The particles were located on primordial yolk platelets and on the superficial layer of small yolk platelets in stage III oocytes, while they were sparse or not present at all on large yolk platelets in stage IV and V oocytes. These results indicate that cathepsin D plays a key role in vitellogenesis by cleaving endocytosed vitellogenin to yolk proteins in developing oocytes.
Modulatory effects mediated by metabotropic glutamate receptor 5 on lateral geniculate nucleus relay cells
Authors: De Labra Carmen , Rivadulla Casto , Cudeiro Javier 
Published: January 2005

AbstractGlutamate is thought to be the excitatory neurotransmitter in the lateral geniculate nucleus (LGN) of the cat, mediating visual transmission from the retina via ionotropic receptors of both d,l‐α‐amino‐3‐hydroxy‐5‐α‐methyl‐4‐isoxazolepropionate and N‐methyl‐d‐aspartate subtypes. Moreover, glutamate also exerts an important modulatory influence on LGN cells, where metabotropic glutamate receptors (mGluRs) seem to play a crucial role. Here we show in anesthetized adult cats that iontophoretic application of the specific mGluR5 antagonist 2‐methyl‐6‐(phenylethynyl)‐pyridine (MPEP) produced two, distinctly different, effects on LGN neurons. Visual responses to flashing spots and drifting gratings were attenuated (decreased by an average of 59%) in 13 of 23 of the cells but augmented (increased by an average of 60%) in 10 of 23 of the cells. Further, in each case when the specific mGluR5 agonist (R,S)‐2‐chloro‐5‐hydroxyphenylglycine was applied, the effects obtained were the opposite to those of MPEP. Data obtained in a second group of experiments to determine a possible interaction between mGluR5 blockade by MPEP and glutamate ionotropic receptors show that, in the majority of neurons (11 of 15, 73%), the MPEP‐mediated effects seem to be independent of N‐methyl‐d‐aspartate and d,l‐α‐amino‐3‐hydroxy‐5‐α‐methyl‐4‐isoxazolepropionate receptor activity. Our results demonstrate a physiological role for mGluR5 in controlling retinal input and show, in vivo, a more intricate scenario than previously suggested, highlighting the complexity of metabotropic receptor interactions with excitatory and inhibitory elements in the thalamus.
Cortical oscillatory activity during spatial echoic memory
Authors: Kaiser Jochen , Walker Florian , Leiberg Susanne , Lutzenberger Werner 
Published: January 2005

AbstractIn human magnetoencephalogram, we have found gamma‐band activity (GBA), a putative measure of cortical network synchronization, during both bottom‐up and top‐down auditory processing. When sound positions had to be retained in short‐term memory for 800 ms, enhanced GBA was detected over posterior parietal cortex, possibly reflecting the activation of higher sensory storage systems along the hypothesized auditory dorsal space processing stream. Additional prefrontal GBA increases suggested an involvement of central executive networks in stimulus maintenance. The present study assessed spatial echoic memory with the same stimuli but a shorter memorization interval of 200 ms. Statistical probability mapping revealed posterior parietal GBA increases at 80 Hz near the end of the memory phase and both gamma and theta enhancements in response to the test stimulus. In contrast to the previous short‐term memory study, no prefrontal gamma or theta enhancements were detected. This suggests that spatial echoic memory is performed by networks along the putative auditory dorsal stream, without requiring an involvement of prefrontal executive regions.
Pro‐apoptotic protein glyceraldehyde‐3‐phosphate dehydrogenase promotes the formation of Lewy body‐like inclusions
Authors: Tsuchiya Katsumi , Tajima Hisao , Kuwae Toyoyasu , Takeshima Takao , Nakano Toshiya , Tanaka Masaharu , Sunaga Katsuyoshi , Fukuhara Yoko , Nakashima Kenji , Ohama Eisaku , Mochizuki Hideki , Mizuno Yoshikuni , Katsube Nobuo , Ishitani Ryoichi 
Published: January 2005

AbstractGlyceraldehyde‐3‐phosphate dehydrogenase (GAPDH) has long been recognized as a classical glycolytic protein; however, previous studies by our group and others have demonstrated that GAPDH is a general mediator initiating one or more apoptotic cascades. Our most recent findings have elucidated that an expression of a pro‐apoptotic protein GAPDH is critically regulated at the promoter region of the gene. Apoptotic signals for its subsequent aggregate formation and nuclear translocation are controlled by the respective functional domains harboured within its cDNA component. In this study, coexpression of GAPDH with either wild‐type or mutant (A53T) α‐synuclein and less likely with β‐synuclein in transfected COS‐7 cells was found to induce Lewy body‐like cytoplasmic inclusions. Unlike its full‐length construct, the deleted mutant GAPDH construct (C66) abolished these apoptotic signals, disfavouring the formation of inclusions. The generated inclusions were ubiquitin‐ and thioflavin S‐positive appearing fibrils. Furthermore, GAPDH coimmunoprecipitated with wild‐type α‐synuclein in this paradigm. Importantly, immunohistochemical examinations of post mortem materials from patients with sporadic Parkinson's disease revealed the colocalized profiles immunoreactive against these two proteins in the peripheral zone of Lewy bodies from the affected brain regions (i.e. locus coeruleus). Moreover, a quantitative assessment showed that about 20% of Lewy bodies displayed both antigenicities. These results suggest that pro‐apoptotic protein GAPDH may be involved in the Lewy body formation in vivo, probably associated with the apoptotic death pathway.
AMPA receptor desensitization as a determinant of vulnerability to focally evoked status epilepticus
Authors: Fornai Francesco , Busceti Carla L. , Kondratyev Alexei , Gale Karen 
Published: January 2005

AbstractWithin the area tempestas (AT) in the anterior piriform cortex, unilateral microinfusions of GABA receptor antagonists and glutamate receptor agonists trigger brief episodic limbic seizures. In the present study, we document a synergistic effect of coinfusing bicuculline (GABAA receptor antagonist) with either carbachol (muscarinic receptor agonist) or cyclothiazide (inhibitor of AMPA receptor desensitization) but not with glutamate receptor agonists (AMPA, NMDA or kainate) in the rat AT. In particular, coadministration of bicuculline (118 pmol) with either carbachol (328 pmol) or cyclothiazide (1.2 nmol) triggered continuous self‐sustaining seizures (status epilepticus; SE). Cyclothiazide alone did not evoke seizures. Although blockade of NMDA receptors with AP‐7 (100 or 500 pmol) prevented episodic seizures evoked by carbachol or bicuculline alone, it was without effect on the continuous seizures evoked by combined treatments. NMDA‐insensitive self‐sustaining seizures were also evoked by the combination of AMPA and cyclothiazide. Regardless of the mechanism by which SE was evoked, it was prevented only by an AMPA receptor antagonist, NBQX, thus reinforcing the crucial role of AMPA receptors in the transition to SE. Further evidence for AMPA receptor regulation of seizure severity came from the overexpression of the GluR1 AMPA receptor subunit in AT. This resulted in substantially increased severity of bicuculline‐evoked seizures that was reversed by focal application of NBQX. Thus, desensitization of AMPA receptors appears to limit the duration and severity of seizure activity, and a failure of this mechanism, or an overabundance of slowly desensitizing AMPA receptors, predisposes to severe and prolonged seizures.
Functional interaction between the associative parietal cortex and hippocampal place cell firing in the rat
Authors: Save Etienne , Paz‐Villagran Vietminh , Alexinsky Tatiana , Poucet Bruno 
Published: January 2005

AbstractThe hippocampus and associative parietal cortex (APC) both contribute to spatial memory but the nature of their functional interaction remains unknown. To address this issue, we investigated the effects of APC lesions on hippocampal place cell firing in freely moving rats. Place cells were recorded from APC‐lesioned and control rats as they performed a pellet‐chasing task in a circular arena containing three object cues. During successive recording sessions, cue manipulations including object rotation in the absence of the rat and object removal in the presence of the rat were made to examine the control exerted by the objects or by non‐visual intramaze cues on place field location, respectively. Object rotations resulted in equivalent field rotation for all cells in control rats. In contrast, a fraction of place fields in APC‐lesioned rats did not rotate but remained stable relative to the room. Object removal produced different effects in APC‐lesioned and control rats. In control rats, most place fields remained stable relative to the previous object rotation session, indicating that they were anchored to olfactory and/or idiothetic cues. In APC‐lesioned rats, a majority of place fields shifted back to their initial, standard location, thus suggesting that they relied on uncontrolled background cues to maintain place field stability. These results provide strong evidence that the hippocampus and the APC cooperate in the formation of spatial memory and suggest that the APC is involved in elaboration of a hippocampal map based on proximal landmarks.
A new trajectory analysis method for migratory planthoppers, Sogatella furcifera (Horváth) (Homoptera: Delphacidae) and Nilaparvata lugens (Stål), using an advanced weather forecast model
Authors: Otuka Akira , Dudhia Jimy , Watanabe Tomonari , Furuno Akiko 
Published: January 2005

Abstract 1 A new method of backward trajectory analysis for planthopper migration is presented. The method consists of two components: an advanced weather forecast model, MM5, for weather simulation, and a migration model for trajectory calculation. The weather forecast model simulates wind fields in which trajectories are calculated by the migration model.2 It is assumed that planthoppers, Sogatella furcifera and Nilaparvata lugens, are transported at wind speeds and in wind directions. The method is evaluated using a migration event observed at Chikugo in Japan on 25 June 1969, which was recorded in hourly catch data.3 The results indicate that the takeoff responsible for the migration occurred at 21 UTC (Coordinated Universal Time) on 23 June along the coastal region of Fujian province in China. This is the first time that the source region of this event has been accurately identified. Determinations of the migrating duration and height are also consistent with observations.4 Although the landing process is not considered in the model, it is shown that the method is able to simulate the migration and accurately estimate various parameters. This study also shows the importance of high‐quality weather simulation.
Termite damage to maize grown in agroforestry systems, traditional fallows and monoculture on nitrogen‐limited soils in eastern Zambia
Authors: Sileshi G. , Mafongoya P. L. , Kwesiga F. , Nkunika P. 
Published: January 2005

Abstract 1 Termites cause significant damage to maize and other crops in southern Africa. Several studies were conducted with the objective of determining the difference in termite damage to maize in various land use systems between monoculture maize, maize grown using traditional fallows and improved fallows.2 In an experiment conducted at four sites on noncoppicing fallows, maize planted after Tephrosia candida 02971 fallows had lower termite damage compared with fully fertilized monoculture maize. However, the termite suppression was not low enough to warrant rotation of noncoppicing fallows for termite management..3 In four experiments comparing termite damage to maize grown in monoculture and in coppicing fallows, fully fertilized monoculture maize had a higher percentage of lodged plants compared with maize grown in pure Leucaena leucocephala, Gliricidia sepium and Acacia anguistissima fallows or in a mixture of A. anguistissima + Sesbania sesban or Tephrosia vogelii + S. sesban.4 More than 50–75% of the variance in maize yield was explained by preseason inorganic nitrogen and termite damage. However, termite damage to maize was not influenced by inorganic nitrogen, which represents nitrogen readily available to maize. The decomposition rate of biomass (related to lignin + polyphenol to nitrogen ratio) and water retention under fallows also appeared to influence termite damage.5 It is concluded that maize grown in L. leucocephala, G. sepium, A. anguistissima and S. sesban fallows suffers less termite damage and produces maize yields comparable with conventionally tilled and fully fertilized monoculture maize.
Larval survival and development of susceptible and resistant Ostrinia nubilalis (Lepidoptera: Pyralidae) on diet containing Bacillus thuringiensis
Authors: Huang Fangneng , Buschman Lawrent L. , Higgins Randall A. 
Published: January 2005

Abstract  1 Larval survival and development of Dipel‐susceptible and ‐resistant strains of European corn borer, Ostrinia nubilalis (Hübner), were assayed using diets incorporating low doses of a commercial formulation of Bacillus thuringiensis var. kurstaki Berliner (Dipel ES).2 Larval mortality, growth and development, pupation rate and pupal weight were not significantly different between Dipel‐susceptible and ‐resistant strains when larvae were reared on a nontoxic control diet.3 Larval mortality of Dipel‐resistant larvae did not significantly change as Dipel concentration increased at the tested concentrations, whereas mortality of Dipel‐susceptible larvae increased dramatically as Dipel concentration increased.4 Larval development was significantly delayed when larvae were fed diets containing low doses of Dipel.5 Pupation rate and pupal body weight declined as Dipel concentration increased but it decreased faster for the susceptible strain than for the resistant strain.
Laboratory and greenhouse evaluation of a synthetic host volatile attractant for Colorado potato beetle, Leptinotarsa decemlineata (Say)
Authors: Martel J. W. , Alford A. R. , Dickens J. C. 
Published: January 2005

Abstract 1 The attractiveness of potato plants treated with a synthetic host volatile blend [(Z)‐3‐hexenyl acetate (+/–)‐linalool, and methyl salicylate] to newly emerged and 5‐day‐old adult Colorado potato beetle, Leptinotarsa decemlineata (Say), was compared at four doses against untreated control plants and plants treated with an azadirachtin‐based antifeedant in greenhouse cage arenas.2 Attractant‐treated plants (derived release rates of 0, 5.7, 17.1 or 57 µg/h) were significantly more attractive than untreated control plants to newly emerged and 5‐day‐old adults only at 57 µg/h.3 Attractant‐treated plants were significantly more attractive than antifeedant‐treated plants to newly emerged and 5‐day‐old adults at the 5.7 µg/h treatment level and higher. Mean insect density on attractant‐treated plants in the attractant/antifeedant study was significantly higher than in the attractant/control study.4 Habituation to the synthetic attractant was evaluated by exposing adult beetles to the synthetic attractant for 0, 1, 2.5, 4, 8, 12 or 16 h, before release into a wind tunnel in which an attractant‐baited plant model was placed at the upwind end. Insects exposed to the synthetic host attractant for ≤ 8 h moved to the synthetic attractant‐baited plant model whereas insects exposed to the synthetic host attractant for 12 and 16 h did not. Furthermore, beetles exposed to the synthetic attractant for 0 and 1 h moved at rates greater than, or equal to, the median whereas beetles exposed for longer time periods moved at rates significantly less than the median.5 These results demonstrate the potential for using the synthetic plant attractant and an antifeedant as components in a stimulo‐deterrent strategy for management of the Colorado potato beetle as shown by us in another study.
Primary succession of soil Crenarchaeota across a receding glacier foreland
Authors: Nicol Graeme W. , Tscherko Dagmar , Embley T. Martin , Prosser James I. 
Published: January 2005

SummaryThe development of soil archaeal community structures in relation to primary succession in bulk and rhizosphere soil was examined across the forefield of the receding Rotmoosferner glacier in Austria. Using cloning and denaturing gradient gel electrophoresis (DGGE) analysis of reverse transcription polymerase chain reaction (RT‐PCR) products of extracted 16S rRNA, archaeal community structure was compared over a chronosequence representing approximately 150 years of soil development and to reference sites outside the glacier forefield, representing soil exposed for approximately 9500 years. Archaeal community composition was found to be dominated by members of the non‐thermophilic or Group 1 Crenarchaeota, where a dramatic yet highly structured successional sequence was observed. Succession over the 150 years sequence could be identified as occurring in three stages, each of which had a phylogenetically distinct 1.1b crenarchaea community with those organisms present in pioneering and intermediate stages belonging to a lineage distinct from those in developed soils. Climax communities also contained organisms belonging to three other major non‐thermophilic crenarchaeal lineages. Comparison of archaeal communities in the rhizosphere indicated that plant species composition was not the major driver of specific crenarchaeal populations. These results indicate the potential role of soil crenarchaea in the development of soil substrates, as well as ecological diversity within and between major Group 1 lineages.
Enzymatic activity, osmotic stress and degradation of pesticide mixtures in soil extract liquid broth inoculated withPhanerochaete chrysosporiumandTrametes versicolor
Authors: Fragoeiro Silvia , Magan Naresh 
Published: January 2005

SummaryIn this study we examined the extracellular enzymatic activity of two white rot fungi (Phanerochaete chrysosporiumandTrametes versicolor) in a soil extract broth in relation to differential degradation of a mixture of different concentrations (0–30 p.p.m.) of simazine, dieldrin and trifluralin under different osmotic stress (−0.7 and −2.8 MPa) and quantified enzyme production, relevant to P and N release (phosphomonoesterase, protease), carbon cycling (β‐glucosidase, cellulase) and laccase activity, involved in lignin degradation. Our results suggest thatT. versicolorandP. chrysosporiumhave the ability to degrade different groups of pesticides, supported by the capacity for expression of a range of extracellular enzymes at both −0.7 and −2.8 MPa water potential.Phanerochaete chrysosporiumwas able to degrade this mixture of pesticides independently of laccase activity. In soil extract,T. versicolorwas able to produce the same range of enzymes asP. chrysoporiumplus laccase, even in the presence of 30 p.p.m. of the pesticide mixture. Complete degradation of dieldrin and trifluralin was observed, while about 80% of the simazine was degraded regardless of osmotic stress treatment in a nutritionally poor soil extract broth. The capacity of tolerance and degradation of high concentrations of mixtures of pesticides and production of a range of enzymes, even under osmotic stress, suggest potential bioremediation applications.
Catabolism of sulfamate by Mycobacterium sp. CF1
Authors: Fulton Craig K. , Cooper Ronald A. 
Published: January 2005

SummaryA bacterium able to utilize sulfamate as N‐source for growth was isolated from soil and identified as a Mycobacterium sp. An apparently previously unrecorded enzyme, sulfamate hydrolase (EC 3.10.1.‐), converts sulfamate to equimolar amounts of ammonia and sulfate. This enzyme was purified to homogeneity and had a Km for sulfamate of 26.36 ± 4.01 mM. Its Specificity Constant value, 74 M−1 s−1, was low, indicating that it was not a particularly good catalyst for this reaction and it may be a hydrolase recruited to this role from some other reaction sequence. However, under equivalent conditions it showed no detectable action on the other sulfamates, cyclamate and sulfamoylbenzoate, or on urea or methylamine.
Role of iron and the TonB system in colonization of corn seeds and roots by Pseudomonas putida KT2440
Authors: Molina María Antonia , Godoy Patricia , Ramos‐González María Isabel , Muñoz Nuria , Ramos Juan L. , Espinosa‐Urgel Manuel 
Published: January 2005

SummaryIron, which is abundant in corn (Zea mays L.) seeds, plays an important role in the initial establishment of Pseudomonas putida KT2440 populations on seeds. Sequestration of seed‐borne iron by chelators decreases the capacity of KT2440 to initiate attachment to corn seeds. The importance of iron for this plant–bacteria interaction is further supported by the fact that mutations in the TonB system, which is key for iron uptake, result in reduced seed colonization. TonB is also a primary determintant of the fitness of P. putida in the rhizosphere, as a deletion mutant shows a clear competitive disadvantage during colonization of corn roots.
Frequent genetic recombination in natural populations of the marine cyanobacterium Microcoleus chthonoplastes
Authors: Lodders Nicole , Stackebrandt Erko , Nübel Ulrich 
Published: January 2005

SummaryA culture‐independent method for multilocus sequence typing of Microcoleus chthonoplastes was developed based on mechanical separation of individual cyanobacterial filaments from natural microbial mat populations through micromanipulation, subsequent polymerase chain reaction (PCR) amplification and sequence analysis of three genetic loci (kaiC, petB/D, rDNA‐ITS). Among 81 individuals sampled from intertidal sand flats of the North Sea and Baltic Sea, we found 8–14 different sequences (alleles) per genetic locus, resulting in 36 distinct genotypes with unique allele profiles. Non‐congruent phylogenetic gene trees for the three loci analysed and split decomposition analysis indicated the occurrence of horizontal genetic exchange. The index of association determined for the entire population was 0.096, indicating that recombination occurs frequently enough to cause almost random association (linkage equilibrium) among alleles. Analysing individuals from three different locations in the North Sea and Baltic Sea, we did not find evidence for geographic subdivisions between populations.