bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparative Effects of Diet and Statin on NO Bioactivity and Matrix Metalloproteinases in Hypercholesterolemic Patients With Coronary Artery Disease
Authors: Koh Kwang Kon , Son Ji Won , Ahn Jeong Yeal , Jin Dong Kyu , Kim Hyung Sik , Choi Yu Mi , Kim Dae Sung , Jeong Euy-Myoung , Park Gi Soo , Choi In Suck , Shin Eak Kyun
Published: September 2002

Objective—

We investigated the effects of statin compared with the American Heart Association (AHA) Step I Diet on lipoproteins, vasomotor function, tumor necrosis factor (TNF)-α, and serological markers of plaque stability. Furthermore, we investigated the mechanism of regulation suggested by experimental studies.

Methods and Results—

For 14 weeks, we administered AHA diet+placebo and AHA diet+simvastatin (20 mg daily) to 31 and 32 randomly selected patients with coronary artery disease, respectively. Compared with diet alone, simvastatin significantly improved the percent flow-mediated dilator response to hyperemia from 3.37±2.28% to 5.89±2.35% (
P
<0.001) and lowered plasma levels of C-reactive protein from 0.48 to 0.10 mg/dL (
P
<0.001), TNF-α from 3.38 to 2.79 pg/mL (
P
<0.001), total matrix metalloproteinase (MMP)-9 from 36 to 28 ng/mL (
P
=0.006), and tissue inhibitor of matrix metalloproteinase-1 from 80±30 to 74±23 ng/mL (
P
=0.041), and simvastatin lowered to a greater extent MMP-9 activity (from 71 to 52 ng/mL,
P
=0.006) and MMP-9 activity/tissue inhibitor of matrix metalloproteinase-1 ratios (
P
=0.018), although this difference did not reach statistical significance. There were significant correlations between the degree of changes in TNF-α and the degree of changes in MMP-9 activity (
r
=0.424,
P
=0.016). However, no significant correlations between lipoprotein levels or flow-mediated dilation percentages and levels of plaque stability markers were determined (−0.208≤
r
≤0.243).

Conclusions—

Simvastatin reduced serological markers of inflammation and plaque stability, independent of lipoprotein changes.
Low Density Lipoproteins Downregulate Lysyl Oxidase in Vascular Endothelial Cells and the Arterial Wall
Authors: Rodríguez Cristina , Raposo Berta , Martínez-González José , Casaní Laura , Badimon Lina
Published: September 2002

Objective—

Hypercholesterolemia induces endothelial dysfunction, a hallmark of the atherosclerotic process, modulating the expression of key genes in vascular endothelial cells.

Methods and Results—

By differential display analysis, we have studied the effect of high concentrations of native low density lipoprotein (LDL) on endothelial gene expression. mRNA levels of lysyl oxidase (LOX), an enzyme involved in collagen and elastin cross-linking, were downregulated by LDL treatment in endothelial cells in a dose- and time-dependent manner (80% of inhibition by 180 mg/dL LDL for 24 hours). This reduction of LOX expression was associated with a decrease in LOX activity (40% and 54% of inhibition after 24 and 48 hours of LDL treatment, respectively). LOX mRNA half-life was not modified by LDL, but transcriptional inhibition blocked the effect of LDL. Inhibition of LOX activity by either LDL or β-aminopropionitrile, an inhibitor of LOX, increased endothelial permeability (192±0.19- and 3.37±0.74-fold, respectively). Interestingly, a reduction in LOX expression (3.5-fold) was observed in vivo in the vascular wall of hypercholesterolemic pigs.

Conclusions—

These findings suggest that LDL downregulation of LOX could contribute to the endothelial dysfunction caused by hypercholesterolemia, thus contributing to atherosclerotic plaque formation.
Plasma Nitrosothiols Contribute to the Systemic Vasodilator Effects of Intravenously Applied NO
Authors: Rassaf Tienush , Kleinbongard Petra , Preik Michael , Dejam André , Gharini Putrika , Lauer Thomas , Erckenbrecht Julia , Duschin Alexej , Schulz Rainer , Heusch Gerd , Feelisch Martin , Kelm Malte
Published: September 2002

Higher doses of inhaled NO exert effects beyond the pulmonary circulation. How such extrapulmonary effects can be reconciled with the presumed short half-life of NO in the blood is unclear. Whereas erythrocytes have been suggested to participate in NO transport, the exact role of plasma in NO delivery in humans is not clear. Therefore, we investigated potential routes of NO decomposition and transport in human plasma. NO consumption in plasma was accompanied by a concentration-dependent increase in nitrite and
S
-nitrosothiols (RSNOs), with no apparent saturation limit up to 200 μmol/L. The presence of red blood cells reduced the formation of plasma RSNOs. Intravenous infusion of 30 μmol/min NO in healthy volunteers increased plasma levels of RSNOs and induced systemic hemodynamic effects at the level of both conduit and resistance vessels, as reflected by dilator responses in the brachial artery and forearm microvasculature. Intravenous application of
S
-nitrosoglutathione, a potential carrier of bioactive NO, mimicked the vascular effects of NO, whereas nitrite and nitrate were inactive. Changes in plasma nitrosothiols were correlated with vasodilator effects after intravenous application of
S
-nitrosoglutathione and NO. These findings demonstrate that in humans the pharmacological delivery of NO solutions results in the transport and delivery of NO as RSNOs along the vascular tree.
The taxonomy of the family Xyalidae Chitwood, 1951 (Monhysterida: Nematoda): a cladistic analysis
Authors: Trueman John , Nicholas Warwick
Published: September 2002

A cladistic analysis of the family Xyalidae has been carried out, with selected Monhysteridae and Sphaerolaimidae as presumptive outgroups. Forty nine characters, taken from published descriptions, were scored for 91 species from 33 genera. The way in which the characters were coded is illustrated by drawings and graphs. Phylogenetic analyses were conducted with the programs PAUP*4.0d65 and PAUP*4.0b2. Neighbour-joining and parsimony trees were constructed and the preferred consensus parsimony tree is presented. The tree has been divided into 15 groups for purposes of discussion. All eight species of Monhysteridae form a separate clade consistent with outgroup status, but the four species of Sphaerolaimidae are not separated from Xyalidae. Several of the Daptonema species, Pseudosteineria plus Steineria, and Rhynchonematinae form three well supported clades. Other groupings are much less well supported and are presumed to be paraphyletic. Many published descriptions do not include sufficient detail to allow relationships to be determined and suggestions are made as to data which should be included in future taxonomic descriptions of Xyalidae.
Variation in entomopathogenic nematode (Steinernematidae and Heterorhabditidae) infective-stage jumping behaviour
Authors: Kaya Harry , Campbell James
Published: September 2002

Species and strains of entomopathogenic nematodes (Heterorhabditidae and Steinernematidae) were assessed for the expression of standing and jumping behaviour. Jumping occurred in 11 species of Steinernema, but the rate of jumping varied considerably among the species. Variation in the duration of crawling bouts, the tendency to body wave, the rate of standing, the duration of standing bouts, and the tendency to jump after standing contributed to the differences in frequency of jumping among species. Within a species, nematodes that jumped were similar in size, infectivity and sex ratio to those that did not jump, but jumpers tended to be more infective and to have lost their sheath (i.e., the second stage cuticle). This comparison of species is an important first step in assessing the adaptive value of jumping behaviour as part of the foraging strategies of entomopathogenic nematodes.
Does osmoregulatory behaviour in entomopathogenic nematodes predispose desiccation tolerance?
Authors: Liu Qhi-Zhi , Glazer Itamar , Wright Denis , Piggott Simon
Published: September 2002

Infective juveniles of four isolates of entomopathogenic nematodes placed into balanced (mixed) salt solutions displayed varying levels of ability to osmoregulate under hyperosmotic conditions. The isolate with the greatest desiccation tolerance (Steinernema carpocapsae SCB-L1) showed the greatest osmoregulatory ability. However, the isolate with the poorest desiccation tolerance (Heterorhabditis sp. HIS-33) could also osmoregulate. One isolate with moderate desiccation tolerance (H. bacteriophora HP88) had the poorest osmoregulatory ability while another (HIS-28) showed good osmoregulatory ability. This shows that there is not necessarily a close link between hypo-osmotic regulation and desiccation tolerance. The need for separate screens for these different survival attributes is, therefore, indicated. Assessment of Heterorhabditis sp. isolate HIS-28 found that osmoregulatory ability and percent survival was greater in balanced salt solutions compared with single salt solutions, providing indirect evidence for a specific ionic regulation mechanism.
Speciation in the Acugutturidae (Nematoda: Aphelenchida)
Authors: Adams Byron , Silvain Jean-François , Marti Orville
Published: September 2002

Ectoparasitic nematodes (Acugutturus, Vampyronema and Noctuidonema) of the family Acugutturidae from 13 species of Lepidoptera (moths) and one species of Blattodea (cockroaches) were collected, measured and analysed by discriminant analysis in order to identify conspecifics and to determine which morphological characters were useful in defining differences between nematodes on different host species. The position of the excretory pore posterior to the metacorpus clearly differentiates Acugutturus parasiticus from Noctuidonema and Vampyronema. Two populations of A. parasiticus on Periplaneta americana from the West Indian islands of St Lucia and Guadeloupe are conspecific. Nematodes resembling Vampyronema, collected from two genera of Sphingidae in Guadeloupe are characterised by extremely long stylets, equal to ca 37% of the body length, and may represent a new genus. Noctuidonema from four species of Spodoptera (Noctuidae) are conspecific. However, a somewhat different Noctuidonema from the noctuid Pseudaletia unipuncta may represent a new species, based primarily on its shorter stylet length. Simple spicule structure, a smaller V percentage, and a shorter stylet in Vampyronema are characters that best define its differences from Noctuidonema. Nematodes on the noctuids Anicla infecta and Eulepidotis addens probably represent two new species of Vampyronema. There was no clear differentiation between nematodes on the noctuids Mocis disseverans, M. latipes, Agrapha oxygramma and Orthodes crenulata, and they are all probably conspecific with V.dibolia. Thus far, Noctuidonema has been found only on the trifine noctuids Spodoptera and Pseudaletia, whereas Vampyronema has been found on both trifine and quadrifine noctuids. We found evidence for sequential evolution, but not co-evolution, between these ectoparasitic nematodes and their lepidopteran hosts.
Paravulvus rhodopensis sp. n. (Nematoda: Nygolaimidae) and three known species from Bulgaria, with notes on the taxonomy of the genus
Authors: Lazarova Stela , Loof Pieter , Peneva Vlada
Published: September 2002

One new and three known species of the genus Paravulvus Heyns, 1968 from forests in Bulgaria are described and illustrated. Paravulvus rhodopensis sp. n. is a bisexual species characterised by a relatively thick cuticle with fine transverse striation, head region offset by a depression, mural tooth deltoid 6-7 μm long, presence of paravulvae posterior to vulva, tail bluntly conical rounded, 24-28 μm long with 7-10 μm hyaline part. Males with one adanal pair and a row of 11-14 supplements, spicules 31-42 μm and tail 22.0-26.5 μm long. Additional morphological and metrical data for P. acuticaudatus (Thorne, 1930), P. hartingii (de Man, 1880) and P. heynsi Vinciguerra, 1987 are presented. Paravulvus acuticaudatus and P. heynsi are new geographical records. An emended diagnosis and revised classification of the genus Paravulvus are proposed, and an identification key to the species is provided. Paravulvus paraamphigonicus (Altherr, 1950) is regarded as a synonym of P.hartingii.
Variation in virulence of cereal cyst nematode populations from North Africa and Asia
Authors: Valette Sylvie , Rivoal Roger , Mokabli Aïssa , Gauthier Jean-Pierre
Published: September 2002

Eight populations of Heterodera avenae, H. filipjevi and H. latipons were tested in Petri dishes with six cereal differentials of the International Test Assortment and a set of resistant genotypes of wheats. Ratios of white females/juveniles inoculated were equivalent to those obtained previously in tubes and pots and confirmed the validity of the miniaturised technique used to study the virulence/resistance relationships of these nematodes and cereals. The populations were differentiated by virulence to barley differentials and a new group of pathotypes of H. avenae originating from Algeria was established. Differentiation among H. avenae populations from North Africa and West Asia was clearly demonstrated by their (a)virulence to the gene Cre1 in Triticum aestivum cv. Loros. As previously observed, cultivated and wild oats were poor hosts for Mediterranean populations of H. avenae, but contrasting host responses were observed for a physiological winter type of oat. In addition to describing the virulence status of H. filipjevi and H. latipons populations to barley, oat and wheat differentials, these results provide information for the introduction of resistance to barley and wheat breeding programmes.
Responses of nematode species composition to factorial addition of carbon, fertiliser, bactericide and fungicide at two sub-arctic sites
Authors: Jonasson Sven , Schmidt Inger , Michelsen Anders , Ruess Liliane
Published: September 2002

Nutrient availability is a major constraint on plant production and carbon storage in arctic ecosystems but knowledge on the decomposer food web interactions and their effect on nutrient cycling is scarce. We manipulated the soil food web at two contrasting subarctic sites, a low altitude heath and a high altitude fell-field. The influx of nutrients and energy in the soil was increased by addition of fertiliser nitrogen, phosphorus and potassium and of labile carbon (sugar). In addition, two bactericides (penicillin and streptomycin) and a fungicide (benomyl) were applied to manipulate the bacterial and fungal component of the soil. Experiments were carried out in a factorial design with repeated additions over four growing seasons. The present study investigated the nematode fauna and the effects of the manipulations on the abundance of nematode species. Fertilisation resulted in an increase of general opportunists, especially Aphelenchoides. Application of carbon or bactericides had only minor impact on the nematode community. In contrast, the fungicide was very toxic to non-target organisms and greatly reduced the abundance of most nematode species, although Acrobeloides buetschlii showed tolerance and greatly increased in number. At both sites, Eudorylaimus was most affected by the treatments. Generally the manipulations performed resulted in a significant increase in stress tolerant or competitive dominant nematode species.
Incidence of plant-parasitic nematodes in natural and semi-natural mountain grassland and the host status of some common grass species
Authors: Navas Alfonso , Talavera Miguel
Published: September 2002

A plant-parasitic nematode survey was undertaken in mountainous pastures of southern Spain. Sixty-three species of plant-parasitic nematodes distributed over 25 genera were associated with pastures and grasslands in southern Spain. Paratylenchus species (P. microdorus, P. similis, P. nanus and P. ciccaronei) were the most abundant and prevalent plant-parasitic nematodes found. Pratylenchus neglectus and P.thornei were widely distributed in 55 and 41% of sites, respectively. Amplimerlinius globigerus, Helicotylenchus digonicus, H. dihystera, H. tunisiensis, Merlinius brevidens, M. microdorus, Rotylenchus unisexus and Scutylenchus quadrifer were found in more than 10% of the fields, on occasion at densities of more than 200 per 100 cm³ of soil. A further 49 species of plant-parasitic nematodes were identified and reported. A pot experiment, using a range of grasses and forage legumes adapted to the zone, ascertained the host status of the most abundant plant-parasitic nematodes. Helicotylenchus digonicus, M. microdorus and P.microdorus populations were maintained or increased by all grasses or legumes tested. In general, grasses were better hosts of P.neglectus and P.thornei than the pasture legumes tested. Medicago minima reduced P.thornei densities after 3 months of growing.
3‐D magnetic inversion with data compression and image focusing
Authors: Portniaguine Oleg , Zhdanov Michael S.
Published: September 2002

We develop a method of 3‐D magnetic anomaly inversion based on traditional Tikhonov regularization theory. We use a minimum support stabilizing functional to generate a sharp, focused inverse image. An iterative inversion process is constructed in the space of weighted model parameters that accelerates the convergence and robustness of the method. The weighting functions are selected based on sensitivity analysis. To speed up the computations and to decrease the size of memory required, we use a compression technique based on cubic interpolation.

Our method is designed for inversion of total magnetic anomalies, assuming the anomalous field is caused by induced magnetization only. The method is applied to synthetic data for typical models of magnetic anomalies and is tested on real airborne data provided by ExxonMobil Upstream Research Company.
Free‐surface boundary conditions for elastic staggered‐grid modeling schemes
Authors: Mittet Rune
Published: September 2002

I present an accurate, stable, and simple implementation of the elastic free surface for staggered‐grid modeling schemes. The method is based on the presumption that the elastic Hooke's tensor on the free surface can be taken as similar to a transversely isotropic medium. The anisotropic elastic properties are then analyzed. The final scheme is isotropic, but with modified elastic properties on the free surface. The proposed scheme shows good agreement with an analytical solution.

It is shown that the Rayleigh wave can not be properly resolved at two gridpoints per shortest wavelength if the shortest wavelength is calculated as the Rayleigh‐wave velocity over the maximum frequency. The Rayleigh wave is exponentially damped away from the free surface and requires denser sampling than purely propagating waves.
Fluvial geomorphology of Indian rivers: an overview
Authors: Kale Vishwas S.
Published: September 2002

The rivers of India reveal certain special characteristics because they undergo large seasonal fluctuations in flow and sediment load. The rivers are adjusted to an array of discharges, and most rivers exhibit morphologies that are related to high-magnitude floods. In the last 100 years primarily hydraulic engineers have contributed to the understanding of the fluvial forms and processes. Though this trend has continued even today, in recent decades some interesting fluvial research has also been carried out by earth scientists. Four large rivers, namely Brahmaputra, Kosi, Indus and Narmada, have received greater attention from fluvial geomorphologists.

The major themes in Indian fluvial geomorphology include the hydrology of monsoonal rivers; forms and processes in alluvial channels; causes of avulsion, channel migration; and anomalous variations in channel patterns; dynamics of suspended sediment; and the geomorphic impacts of floods. Studies of bedrock channels are far less than similar studies in alluvial channels. Only a few rivers have been investigated in this respect.

Studies indicate that the Himalayan rivers are different in many respects from those of the Indian Peninsula. The former occupy a highly dynamic environment with extreme variability in discharge and sediment load. Earthquakes and landslides also have a great impact on these rivers from time to time. Consequently, the rivers are characterized by frequent changes in shape, size, position and planform. In comparison, the adjustments in Peninsular rivers are less frequent and of a much smaller magnitude.

An inescapable conclusion is that in the tropical monsoonal environment, large floods are important geomorphic agents that temporarily affect the forms and behavioural characteristics of some rivers, but leave a lasting effect on others. In magnitude-frequency terms, large floods are major formative events in many rivers of the Indian region in general and the Indian Peninsula in particular.
The expression of native and oxidized LDL receptors in brain microvessels is specifically enhanced by astrocytes‐derived soluble factor(s)
Authors: Lucarelli Marco , Borrelli Valeria , Fiori Anna , Cucina Alessandra , Granata Filippo , Potenza Rosa Luisa , Scarpa Sigfrido , Cavallaro Antonino , Strom Roberto
Published: September 2002

Ex vivo rat brain microvessels express receptors for native as well as for oxidized low‐density lipoproteins. In brain microvessels‐derived endothelial cells, the expression levels of both receptors were enhanced by co‐cultivation with rat astrocytes, even in the absence of actual contact between the two cell types, suggesting a soluble factor(s)‐based mechanism of induction. No modulation effect could be evidenced in a heterologous cellular system. Since both receptors were found to be expressed also in astrocytes, these cells are likely to contribute substantially to the lipoprotein management at the blood–brain barrier and in the brain compartment.
Direct addition of BimL to mitochondria does not lead to cytochrome c release
Authors: Terradillos Olivier , Montessuit Sylvie , Huang David C.S , Martinou Jean-Claude
Published: September 2002

Pro‐apoptotic members of the Bcl‐2 family can be subdivided in two classes according to their structure: a group including Bax, Bak, and Bok that display Bcl‐2 homology (BH) 1, BH2 and BH3 domains and a second group including Bid (BH3 interacting domain death agonist), Bad, Bim (Bcl‐2 interacting mediator of cell death) and several others that contain only a BH3 domain, the BH3‐only proteins. The BH3‐only proteins have been proposed to activate pro‐apoptotic members of the Bax subfamily to trigger a mitochondrial pathway that leads to the release of cytochrome c and other apoptogenic factors. Here we report that the mechanism of action of Bim is different from that of Bid. Although overexpression of Bid or Bim in cells leads to cytochrome c release, only Bid is able to trigger the release of cytochrome c through Bax activation when added directly to isolated mitochondria. BimL, although unable to activate Bax, can directly inhibit Bcl‐2 or Bcl‐xL. Our data suggest two functional classes of BH3‐only proteins: those such as Bid which directly activate Bax‐like proteins leading to mitochondrial membrane permeability and apoptosis and those such as Bim which inhibit anti‐apoptotic proteins and render the cells more susceptible to apoptogenic stimuli.
Discriminant analysis to evaluate clustering of gene expression data
Authors: Méndez Marco A , Hödar Christian , Vulpe Chris , González Mauricio , Cambiazo Verónica
Published: September 2002

In this work we present a procedure that combines classical statistical methods to assess the confidence of gene clusters identified by hierarchical clustering of expression data. This approach was applied to a publicly released Drosophila metamorphosis data set [White et al., Science 286 (1999) 2179–2184]. We have been able to produce reliable classifications of gene groups and genes within the groups by applying unsupervised (cluster analysis), dimension reduction (principal component analysis) and supervised methods (linear discriminant analysis) in a sequential form. This procedure provides a means to select relevant information from microarray data, reducing the number of genes and clusters that require further biological analysis.
The gene expression and deficiency phenotypes of Cockayne syndrome B protein in Caenorhabditis elegans
Authors: Lee Myon Hee , Ahn Byungchan , Choi In Soon , Koo Hyeon-Sook
Published: September 2002

The Caenorhabditis elegans Cockayne syndrome B protein homologue is encoded by 10 exons of the predicted open reading frame F53H4.1. The gene is expressed in germ cells and all somatic cells of the embryonic to adult stage. Although the gene expression was ubiquitous, its expression level was relatively higher in dividing cells and cells that play fundamental roles in essential physiological functions such as feeding, sensation, and reproduction. RNA interference of the gene hypersensitized C. elegans to UV radiation, as observed in enhanced germ cell proliferation arrest and apoptosis, and increased embryonic lethality, suggesting its role in nucleotide excision repair.
Does chloroquine really act through oxidative stress?
Authors: Monti Diego , Basilico Nicoletta , Parapini Silvia , Pasini Erica , Olliaro Piero , Taramelli Donatella
Published: September 2002

To assess whether molecular oxygen and oxidative stress contribute to chloroquine activity, we cultivated strains of Plasmodium falciparum in erythrocytes with carboxyhemoglobin and an atmosphere containing 2% CO, 5% CO2 and 93% N2. Results indicate that, contrary to common belief, oxygen is not involved in the activity of chloroquine. Reactive radicals formation is suggested.
Transposon‐like Correia elements: structure, distribution and genetic exchange between pathogenic Neisseria sp
Authors: Buisine Nicolas , Tang Christoph M , Chalmers Ronald
Published: September 2002

Correia elements are a prominent feature of all four Neisseria genome sequences. We report an in silico analysis of the structure and genomic distribution of these elements and some preliminary biochemical data. Correia elements fall into four major families, distinguished by a 50 bp internal deletion and five point mutations. The elements resemble a transposon with 25 bp inverted repeats and a TA duplication at the target site. Within the element there is a functional integration host factor binding site. The genomic distribution of Correia elements is essentially random except for some small Correia‐less regions apparently acquired by horizontal transfer. Phylogenetic analysis suggests that their presence predates the divergence of Neisseria meningitidis and Neisseria gonorrhoeae.
Amino acid determinants of α‐synuclein aggregation: putting together pieces of the puzzle
Authors: Uversky Vladimir N , Fink Anthony L
Published: September 2002

Parkinson's disease is the second most common neurodegenerative disease, and results from loss of dopaminergic neurons in the substantia nigra. The aggregation and fibrillation of α‐synuclein in the form of intracellular proteinaceous aggregates (Lewy bodies and Lewy neurites) have been implicated as a causative factor in this disease, as well as in several other neurodegenerative disorders, including dementia with Lewy bodies, Lewy body variant of Alzheimer's disease, multiple system atrophy and Hallervorden–Spatz disease. Thus, the aggregated forms of α‐synuclein play a crucial role in the pathogenesis of the synucleinopathies. However, the molecular mechanisms underlying α‐synuclein aggregation into specific filamentous inclusions remained unknown until recently. Data on the aggregation and fibrillation properties of human α‐, β‐ and γ‐synucleins, mouse α‐synuclein and familial Parkinson's disease mutants of human α‐synuclein (A30P and A53T) are analyzed in order to shed light on the amino acid determinants of synuclein aggregation.
Suppression of DTT‐induced aggregation of abrin by αA‐ and αB‐crystallins: a model aggregation assay for α‐crystallin chaperone activity in vitro1
Authors: Reddy G.Bhanuprakash , Narayanan Sriram , Reddy P.Yadagiri , Surolia Ira
Published: September 2002

The eye lens small heat shock proteins (sHSP), αA‐ and αB‐crystallins, have been shown to function like molecular chaperones, both in vitro and in vivo. It is essential to assess the protective effect of αA‐ and αB‐crystallins under native conditions to extrapolate the results to in vivo conditions. Insulin and α‐lactalbumin have widely been used to investigate the chaperone mechanism of α‐crystallin under native conditions. Due to its smaller size, insulin B‐chain may not represent the binding of putative physiological substrate proteins. As it stands, the aggregation of α‐lactalbumin and binding of α‐crystallin to it varies under different experimental conditions. Abrin, a ribosome inactivating protein isolated from the seeds of Abrus precatorius, consists of a 30 kDa A‐chain and a lectin‐like B‐chain of 33 kDa joined by a single disulfide bond. Reduction of the disulfide link between the two chains of abrin leads to the aggregation of the B‐chain. In this study, we demonstrate that dithiothreitol (DTT)‐induced aggregation of abrin B‐chain could be monitored by light scattering similar to that of insulin. Moreso, this process could be suppressed by recombinant human αA‐ and αB‐crystallins in a concentration dependent manner, notably by binding to aggregation prone abrin B‐chain. SDS–PAGE and HPLC gel filtration analysis indicate that there is a soluble complex formation between α‐crystallin and abrin B‐chain. Interestingly, in contrast to insulin, there is no significant difference between αA‐ and αB‐crystallin in suppressing the aggregation of abrin B‐chain at two different temperatures (25 and 37°C). HSP26, an another small heat shock/α‐crystallin family protein, was also able to prevent the DTT‐induced aggregation of abrin. These results suggest that due to relatively larger size of its B‐chain (33 kDa), compared to insulin B‐chain (about 3 kDa), abrin may serve as a better model substrate for in vitro chaperone studies of α‐crystallin and as well as other sHSP.
Modification of heme c binding motifs in the small subunit (NrfH) of the Wolinella succinogenes cytochrome c nitrite reductase complex
Authors: Simon Jörg , Eichler Robert , Pisa René , Biel Simone , Gross Roland
Published: September 2002

The two multiheme c‐type cytochromes NrfH and NrfA form a membrane‐bound complex that catalyzes menaquinol oxidation by nitrite during respiratory nitrite ammonification of Wolinella succinogenes. Each cysteine residue of the four NrfH heme c binding motifs was individually replaced by serine. Of the resulting eight W. succinogenes mutants, only one is able to grow by nitrite respiration although its electron transport activity from formate to nitrite is decreased. NrfH from this mutant was shown by matrix‐assisted laser desorption/ionization mass spectrometry to carry four covalently bound heme groups like wild‐type NrfH indicating that the cytochrome c biogenesis system II organism W. succinogenes is able to attach heme to an SXXCH motif.
PACAP protects neuronal PC12 cells from the cytotoxicity of human prion protein fragment 106–126
Authors: Onoue Satomi , Ohshima Keiichi , Endo Kosuke , Yajima Takehiko , Kashimoto Kazuhisa
Published: September 2002

Misfolding of the prion protein yields amyloidogenic isoforms, and it shows exacerbating neuronal damage in neurodegenerative disorders including prion diseases. Pituitary adenylate cyclase‐activating polypeptide (PACAP) and vasoactive intestinal peptide (VIP) potently stimulate neuritogenesis and survival of neuronal cells in the central nervous system. Here, we tested these neuropeptides on neurotoxicity in PC12 cells induced by the prion protein fragment 106–126 [PrP (106–126)]. Concomitant application of neuropeptide with PrP(106–126) (5×10−5 M) inhibited the delayed death of neuron‐like PC12 cells. In particular, PACAP27 inhibited the neurotoxicity of PrP(106–126) at low concentrations (>10−15 M), characterized by the deactivation of PrP(106–126)‐stimulated caspase‐3. The neuroprotective effect of PACAP27 was antagonized by the selective PKA inhibitor, H89, or the MAP kinase inhibitor, U0126. These results suggest that PACAP27 attenuates PrP(106–126)‐induced delayed neurotoxicity in PC12 cells by activating both PKA and MAP kinases mediated by PAC1 receptor.
Quantification of NF1 transcripts reveals novel highly expressed splice variants
Authors: Vandenbroucke Ina , Vandesompele Jo , De Paepe Anne , Messiaen Ludwine
Published: September 2002

Previously, we have shown that the NF1 gene gives rise to multiple novel splice variants. In the present study, nine NF1 variants were quantified by real‐time PCR in various human tissues. Some of these variants were expressed at low to moderate low levels and possible implications of these findings are discussed. Interestingly, two variants (NF1‐ΔE4b and NF1‐ΔE43) were shown to be highly expressed in specific tissues. NF1‐ΔE43 lacks a nuclear targeting sequence and might be functionally different from full‐length NF1. These novel NF1 splice variants might expand our understanding of the role of neurofibromin.
Transcriptional regulation of nuclear orphan receptor, NOR‐1, by Ca2+/calmodulin‐dependent protein kinase cascade
Authors: Inuzuka Hiroyuki , Tokumitsu Hiroshi , Ohkura Naganari , Kobayashi Ryoji
Published: September 2002

We found that transcription of NOR‐1 (neuron‐derived orphan receptor‐1) is induced by the Ca2+/calmodulin‐dependent protein kinase IV (CaM‐KIV) cascade by differential hybridization screening of a cDNA array using probes prepared from SH‐SY5Y cells infected with recombinant adenoviruses expressing Ca2+/CaM‐independent mutants of CaM‐KIV and CaM‐K kinase (CaM‐KK). Induction of NOR‐1 mRNA expression by the CaM‐KIV cascade was confirmed by RT‐PCR. Promoter analyses indicate that CaM‐KIV cascade response element is located between −162 bp and −42 bp in the 1.7 kb NOR‐1 promoter containing triple cAMP response elements. Disruption of each element significantly reduced the promoter activity, indicating the direct transcriptional regulation of NOR‐1 by CaM‐KIV cascade.
Inhibition of ubiquitin‐dependent proteolysis by a synthetic glycine–alanine repeat peptide that mimics an inhibitory viral sequence
Authors: Leonchiks Ainars , Stavropoulou Vaya , Sharipo Anatoly , Masucci Maria G.
Published: September 2002

The glycine–alanine repeat (GAr) of the Epstein–Barr virus nuclear antigen‐1 is a cis‐acting transferable element that inhibits ubiquitin/proteasome‐dependent proteolysis in vitro and in vivo. We have here examined the effect of a synthetic 20‐mer GAr oligopeptide on the degradation of iodinated or biotin labeled lysozyme in a rabbit reticulocyte lysates in vitro assay. Micromolar concentrations of the GA‐20 peptide inhibited the hydrolysis of lysozyme without significant effect on ubiquitination. Addition of the peptide did not inhibit the hydrolysis of fluorogenic substrate by purified proteasomes and did not affect the ubiquitination of lysozyme. An excess of the peptide failed to compete for binding of a synthetic tetra‐ubiquitin complex to the S5a ubiquitin‐binding subunit of the 19S regulator, confirming that the GAr does not block the access of ubiquitinated substrates to the proteasome. Our data suggest that the GAr may act by destabilizing the interaction of ubiquitinated substrates with the proteasome and promote the premature release of the substrate.
Increased early atherogenesis in young versus old hypercholesterolemic rabbits by a mechanism independent of arterial cell proliferation
Authors: Cortés Marı́a J , Dı́ez-Juan Antonio , Pérez Paloma , Pérez-Roger Ignacio , Arroyo-Pellicer Rosa , Andrés Vicente
Published: September 2002

We sought to determine the relative importance of aging and hypercholesterolemia on atherosclerosis. Although plasma cholesterol levels increased similarly in young and old rabbits fed an atherogenic diet for 2 months, aortic atherosclerotic lesions were more prominent in young animals. This finding was associated with an age‐dependent reduction in the DNA‐binding activity of the proinflammatory nuclear factor κB (NF‐κB) in aortic tissue. Atherosclerotic lesions consisted mostly of macrophages, which displayed a similar proliferative response in both age groups. Independently of the age, medial cell proliferation was low and increased as a function of intimal lesion size. Thus, higher atherogenicity in young rabbits exposed to extreme hypercholesterolemia compared to old counterparts is associated with higher activity of NF‐κB in the juvenile vessel wall without apparent age‐dependent changes in arterial cell proliferation.
A polygalacturonase of animal origin isolated from the root‐knot nematode Meloidogyne incognita1
Authors: Jaubert Stéphanie , Laffaire Jean-Baptiste , Abad Pierre , Rosso Marie-Noëlle
Published: September 2002

The first animal polygalacturonase (PG, EC 2.1.15) encoding cDNA, Mi‐pg‐1, was cloned from the plant parasitic nematode Meloidogyne incognita. The enzymatic activity of MI‐PG‐1 was confirmed after heterologous expression in Escherichia coli. The presence of a predicted signal peptide on the MI‐PG‐1 sequence together with the specific localization of the transcripts of the Mi‐pg‐1 gene in the oesophageal glands of infective juveniles imply that MI‐PG‐1 could be secreted into plant tissues. The potential role of MI‐PG‐1 in parasitism is discussed.
Protein disulfide isomerase of Toxoplasma gondii is targeted by mucosal IgA antibodies in humans
Authors: Meek Bob , Back Jaap Willem , Klaren Vincent N.A , Speijer Dave , Peek Ron
Published: September 2002

Mass spectrometric analysis identified a 49 kDa antigen from Toxoplasma gondii as protein disulfide isomerase (PDI). This antigen is generally recognized by IgA in tears of healthy humans. We determined the complete open reading frame and expressed PDI recombinantly. Recombinant PDI was recognized by IgA in human tears known to contain antibodies specific for the 49 kDa antigen. High expression level and similarity to other protozoan PDIs suggest that T. gondii PDI might be a suitable target for recently described anti‐protozoan drugs. PDI‐specific antibodies clearly constitute part of the mucosal antibody repertoire possibly involved in defence against parasites.
Hypoxia activates a background conductance in freshly isolated pulmonary arterial endothelial cells of the rat
Authors: Hogg Dayle S , Kozlowski Roland Z
Published: September 2002

Utilising the patch‐clamp recording technique we have demonstrated for the first time the effects of hypoxia on the background current in pulmonary arterial endothelial cells. Electrophysiological studies revealed the presence of a novel oxygen‐sensitive, non‐selective cation conductance (I
NSC) in these cells. The inward component of I
NSC was significantly potentiated by hypoxia. Both the inward and outward components of I
NSC were inhibited by both La3+ and Gd3+. Hypoxic activation of I
NSC may provide an important Ca2+ influx pathway essential for the release of a pulmonary‐selective vasoconstrictor pivotal to the sustained phase of hypoxic pulmonary vasoconstriction.
Evidence for two interaction regions for phosphatidylinositol(4,5)‐bisphosphate on mammalian profilin I
Authors: Skare Petra , Karlsson Roger
Published: September 2002

The binding of phosphatidylinositol(4,5)‐bisphosphate (PI(4,5)P2) to profilin at a region distinct from the actin interaction surface is demonstrated by experiments with covalently cross‐linked profilin:β‐actin. The result is in agreement with observations made with several mutant profilins and provides strong evidence for two regions on mammalian profilin mediating electrostatic interaction with phosphatidylinositol lipids; one close to the binding site for poly(L‐proline), and one partially overlapping with the actin‐binding surface. Congruent with this, two plant profilins, which have a reduced number of positive amino acids in one of these regions, displayed a dramatically lower binding to PI(4,5)P2 compared to human profilin I.
Gene expression profiling of cell lines derived from T‐cell malignancies
Authors: Fillmore G.Chris , Lin Zhaosheng , Bohling Sandra D , Robetorye Ryan S , Kim Chan-Hwan , Jenson Stephen D , Elenitoba-Johnson Kojo S.J , Lim Megan S
Published: September 2002

The expression profiles of eight cell lines derived from T‐cell malignancies were compared to CD4‐positive T‐cells using cDNA microarray technology. Unsupervised hierarchical clustering of 4364 genes demonstrated substantial heterogeneity resulting in four distinct groups. While no genes were found to be uniformly up‐ or down‐regulated across all cell lines, we observed 111 over‐expressed genes (greater than two‐fold) and 1118 down‐regulated genes (greater than two‐fold) in the lymphomas as a group when compared to CD4‐positive T‐cells. These included genes involved in cytokine signaling, cell adhesion, cytoskeletal elements, nuclear transcription factors, and known oncogenes and tumor suppressor genes. Quantitative fluorescent reverse transcription‐polymerase chain reaction analysis demonstrated 70% concordance with the microarray results. While freshly isolated malignant cells may differ in their individual expression patterns relative to established cell lines from the same diagnoses, we feel that the variety of different lymphocytic cell lines that we examined provides a representative picture of the molecular pathogenesis of T‐cell malignancies.
The action of N‐acetylglucosaminyltransferase‐V is prevented by the bisecting GlcNAc residue at the catalytic step
Authors: Sasai Ken , Ikeda Yoshitaka , Eguchi Hironobu , Tsuda Takeo , Honke Koichi , Taniguchi Naoyuki
Published: September 2002

Using a purified protein and bisected acceptor oligosaccharides, we demonstrate that N‐acetylglucosaminyltransferase (GnT)‐V transfers a N‐acetylglucosamine residue via a β1,6‐linkage to the bisected oligosaccharides. We also kinetically characterized the substrate specificity of GnT‐V with respect to the bisected oligosaccharide. Although the K
m values for the bisected acceptors were comparable to that for a non‐bisected acceptor, the V
max values for the bisected acceptors were much lower than that for the non‐bisected acceptor. These findings suggest that the acceptor specificity of GnT‐V is determined by the catalytic process rather than by its binding to the substrate. It was also found that the presence of the 2‐N‐acetyl group in the bisecting monosaccharide moiety plays a critical role in determining the catalytic efficiency of the enzyme.
Role of intracellular loops of cannabinoid CB1 receptor in functional interaction with Gα16
Authors: Ho Begonia Y , Current Lori , Drewett James G
Published: September 2002

The cannabinoid CB1 but not the CB2 receptor was demonstrated to couple via Gα16 to activate phospholipase C after co‐expression in COS7 cells. Chimeric CB1/CB2 receptors were used as a model to study receptor–Gα16 interaction. Sequences of the second and third intracellular loops and the carboxy‐terminus were substituted from the CB1 into the CB2 receptor. Only the triple mutant with all three regions replaced activated phospholipase C to a similar extent as the CB1 receptor, suggesting that all three intracellular regions are required for interacting with Gα16. Several sub‐domains within the third intracellular loop were identified for receptor–Gα16 interaction.
Effects of salt and nickel ion on the conformational stability ofBacillus pasteuriiUreE
Authors: Lee Yeon-Hee , Won Hyung-Sik , Lee Mann-Hyung , Lee Bong-Jin
Published: September 2002

UreE, a urease accessory protein, is proposed to be a metallochaperone assisting the nickel incorporation into the urease active site. We investigated the effects of salt and nickel on the conformational stability of the UreE fromBacillus pasteurii(BpUreE), by circular dichroism (CD) and nuclear magnetic resonance spectroscopy accompanying a thermodynamic inspection. Far‐UV CD spectra ofBpUreE showed that both salt and nickel stabilized the ordered structure of the protein. The thermal denaturing ofBpUreE showed a bimodal feature with an aggregation process before thermal unfolding. This thermally induced aggregation could be suppressed by the addition of salt up to 50 mM, and the further addition of salt increased the thermal resistance of the protein. The nickel addition also elevated the thermal resistance ofBpUreE, although it could not prevent the aggregating process. Additionally, the stoichiometry of a specific nickel binding toBpUreE was revealed as one nickel per dimer. Altogether, the present results establish a rather detailed characterization of the thermostability and nickel‐binding property ofBpUreE.
Plasticity of proton pathways in haem–copper oxygen reductases
Authors: Pereira Manuela M , Gomes Cláudio M , Teixeira Miguel
Published: September 2002

Oxygen reductases are the final enzymes in the aerobic respiratory chains catalysing the reduction of dioxygen to water, with the concomitant translocation of protons through the bacterial cytoplasmatic or mitochondrial membranes. Most of these enzymes belong to the family of haem–copper oxygen reductases. Intraprotein proton‐conducting pathways are needed for the chemical reaction and for the translocated protons. Based on sequence and structural analyses, and site‐directed mutagenesis, two proton channels were established for the mitochondrial‐like oxygen reductases. However, the amino acid residues forming these channels are not conserved among the family members. Most importantly, many oxygen reductases do not contain ionisable amino acid residues in the putative proton pathways nor in alternative positions. The diversity of channels in haem–copper oxygen reductases exemplifies the plasticity of proton pathways that occurred throughout evolution, and strongly suggests a substantial role for water as the main proton carrier.
Ethanol cycle in an ethanologenic bacterium
Authors: Kalnenieks U , Galinina N , Toma M.M , Marjutina U
Published: September 2002

A novel redox cycle is suggested, performing interconversion between acetaldehyde and ethanol in aerobically growing ethanologenic bacterium Zymomonas mobilis. It is formed by the two alcohol dehydrogenase (ADH) isoenzymes simultaneously catalyzing opposite reactions. ADH I is catalyzing acetaldehyde reduction. The local reactant ratio at its active site probably is shifted towards ethanol synthesis due to direct channeling of NADH from glycolysis. ADH II is oxidizing ethanol. The net result of the cycle operation is NADH shuttling from glycolysis to the membrane respiratory chain, and ensuring flexible distribution of reducing equivalents between the ADH reaction and respiration.
Association of HSP70 with endonucleases allows the expression of otherwise silent mutations
Authors: Mizumura Hikaru , Shibata Takehiko , Morishima Nobuhiro
Published: September 2002

A subpopulation of the 70 kDa heat shock protein (HSP70) found within the mitochondria of Saccharomyces cerevisiae functions as a stable binding partner of the endonuclease SceI. We have previously found that the SceI endonuclease monomer recognizes and cleaves a unique, 26 bp sequence in vitro. Dimerization with HSP70 changes the specificity of SceI, allowing it to cleave at multiple sequences. This study shows that SuvI, an ortholog of SceI isolated from a different yeast strain, contains two amino acid substitutions, yet it shows the same uni‐site specificity in its monomeric form. Binding of HSP70 to the SuvI monomer confers multi‐site specificity that is different from that exhibited by the HSP70/SceI heterodimer. Mutation of single residues of SceI to the corresponding residue in SuvI provides enzymes with specificities intermediate between SceI and SuvI when complexed with HSP70. These results suggest that HSP70 interaction with certain endonucleases allows the expression of otherwise silent mutations in them, causing a change in enzyme cleavage specificity.