bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sequencing, processing, and localization of the petunia CMS‐associated mitochondrial protein
Authors: Nivison Helen T. , Sutton Claudia A. , Wilson Robin K. , Hanson Maureen R. 
Published: November 2004

SummaryThe petunia mitochondrial fused gene (pcf), which is associated with cytoplasmic male sterility (CMS), is composed of sequences derived from atp9, coxll, and an unidentified reading frame termed urfS. Pcf transcripts are modified by editing at 11 sites. Codon usage and nearest neighbor analysis suggest that the urfS region is not derived originally from a plant mitochondrial coding region. Although the gene contains an open reading frame coding for a 43 kDa protein, a 25 kDa gene product has previously been identified (Nivison and Hanson, 1989). N‐terminal sequencing revealed that the 25 kDa protein is encoded within the urfS portion of pcf and that its actual molecular mass is 19.5 kDa. Through pulse‐chase labeling of protein in isolated mitochondria, the 25 kDa protein was found to be processed from a 43 kDa precursor protein representing the entire pcf gene sequence. Antibodies to synthetic peptides encoded by the atp9 and coxll portions of pcf recognized petunia ATP9 or COXII but no other mitochondrial proteins on immunoblots. Controlled proteolysis experiments showed that both the 43 kDa precursor and the 25 kDa protein are soluble or loosely associated with membranes. Thus, the 25 kDa protein appears to be the only pcf‐encoded protein that accumulates in mitochondria.
Distribution of xylosylation and fucosylation in the plant Golgi apparatus
Authors: Fitchette‐Lainé Anne‐Catherine , Gomord Véronique , Chekkafi Aïcha , Faye Loïc 
Published: November 2004

SummaryAntibodies have been immunopurified which are specific for carbohydrate epitopes containing the β1→2 xylose or α1→3 fucose residues found on complex N‐linked glycans in plants. The antibody specificity was determined by taking advantage of an Arabidopsis thaliana N‐glycosylation mutant which lacks N‐acetyl‐glucosaminyltransferase I and is unable to synthesize complex glycans. These antibodies were used to immunolocalize xylose‐ and fucose‐containing glycoproteins in suspension‐cultured sycamore cells (Acer pseudoplatanus). By mapping the enzymatic reaction products within the Golgi apparatus, the fucosyl‐ and xylosyltransferase subcellular localization was made possible using immunocytochemistry on thin sections of high‐pressure frozen and freeze‐substituted sycamore cells. This procedure allows a much better preservation of organelles, and particularly of the Golgi stack morphology, than that obtained with conventionally fixed samples. Glycoproteins containing β→2 xylose and α1→3 fucose residues were immunodetected in the cell wall, the vacuole, and the Golgi cisternae. The extent of immunolabeling over the different cisternae of 50 Golgi stacks was quantified after treatment with anti‐xylose or anti‐fucose antibodies. Labeling for xylose‐containing glycoproteins was predominent in the medial cisternae, while fucose‐containing glycoproteins were mainly detected in the trans compartment. Therefore, in plants, complex N‐linked glycan xylosylation probably occurs mostly at the medial Golgi level and α1→3 fucose is mainly incorporated in the trans cisternae. Finally, fucose‐ and xylose‐containing glycoproteins were also immunolocalized, albeit to a lesser extent, in earlier Golgi compartments. This indicates that the glycosylation events are a continuous process with some maxima in given compartments, rather than a succession of discrete and compartment‐dependent steps.
Analysis of clones carrying repeated DNA sequences in two YAC libraries of Arabidopsis thaliana DNA
Authors: Schmidt Renate , Putterill Joanna , West Joanne , Cnops Gerda , Robson Frances , Coupland George , Dean Caroline 
Published: November 2004

SummaryYAC clones carrying repeated DNA sequences from the Arabidopsis thaliana genome have been characterized in two widely used Arabidopsis YAC libraries, the EG library and the EW library. Ribosomal, chloroplast and the paracentromeric repeat sequences are differentially represented in the two libraries. The coordinates of YAC clones hybridizing to these sequences are given. A high proportion of EG YAC clones were classified as containing chimaeric inserts because individual clones carried unique sequences and repetitive sequences originating from different locations in the genome. None of the EW YAC clones analysed were chimaeric in this way. YAC clones carrying tandemly repeated sequences, such as the paracentromeric or rDNA sequences, exhibited a high degree of instability. These observations need to be taken into account when using these libraries in the development of a physical map of the Arabidopsis genome and in chromosome walking experiments.
Chemotherapy‐induced cell death in primary cerebellar granule neurons but not in astrocytes: in vitro paradigm of differential neurotoxicity
Authors: Wick Antje , Wick Wolfgang , Hirrlinger Johannes , Gerhardt Ellen , Dringen Ralf , Dichgans Johannes , Weller Michael , B. Schulz Jörg 
Published: November 2004

AbstractThe nervous system is frequently the site of symptomatic toxicity of antineoplastic agents. However, there is limited information about the differential vulnerability of neurons, astrocytes and glioma cells. We have analyzed the effects of four chemotherapeutic drugs (lomustine, cisplatin, topotecan and vincristine) on primary cerebellar granule neurons and astrocytes derived from rats. All drugs led to cell death in cerebellar granule neurons in a concentration‐dependent manner. Comparison of the EC50 values for cerebellar neurons and astrocytes with the median EC50 values of 12 malignant glioma cell lines demonstrated a large therapeutic range for lomustin and cisplatin. Further, this comparison revealed a 100‐fold higher sensitivity of cerebellar neurons towards vincristine and 10‐fold higher sensitivity towards topotecan compared with glioma cells. Astrocytes were generally resistant to vincristine. In cerebellar granule neurons, vincristine and to a lesser extent topotecan induced caspase 3 and caspase 9 cleavage, and enhanced caspase activity and Akt‐dependent expression of phosphorylated BAD. zVAD‐fmk, a caspase inhibitor and brain‐derived neurotrophic factor (BDNF), but not MK‐801, a non‐competitive NMDA receptor antagonist, significantly reduced vincristine‐ or topotecan‐induced cell death.
Tyramine receptor (SER‐2) isoforms are involved in the regulation of pharyngeal pumping and foraging behavior in Caenorhabditis elegans
Authors: Rex Elizabeth , Molitor Scott C. , Hapiak Vera , Xiao Hong , Henderson Megan , Komuniecki Richard 
Published: November 2004

AbstractOctopamine regulates essential processes in nematodes; however, little is known about the physiological role of its precursor, tyramine. In the present study, we have characterized alternatively spliced Caenorhabditis elegans tyramine receptor isoforms (SER‐2 and SER‐2A) that differ by 23 amino acids within the mid‐region of the third intracellular loop. Membranes prepared from cells expressing either SER‐2 or SER‐2A bind [3H]lysergic acid diethylamide (LSD) in the low nanomolar range and exhibit highest affinity for tyramine. Similarly, both isoforms exhibit nearly identical Ki values for a number of antagonists. In contrast, SER‐2A exhibits a significantly lower affinity than SER‐2 for other physiologically relevant biogenic amines, including octopamine. Pertussis toxin treatment reduces affinity for both tyramine and octopamine, especially for octopamine in membranes from cells expressing SER‐2, suggesting that the conformation of the mid‐region of the third intracellular loop is dictated by G‐protein interactions and is responsible for the differential tyramine/octopamine affinities of the two isoforms. Tyramine reduces forskolin‐stimulated cAMP levels in HEK293 cells expressing either isoform with nearly identical IC50 values. Tyramine, but not octopamine, also elevates Ca2+ levels in cells expressing SER‐2 and to a lesser extent SER‐2A. Most importantly, ser‐2 null mutants (pk1357) fail to suppress head movements while reversing in response to nose‐touch, suggesting a role for SER‐2 in the regulation of foraging behavior, and fail to respond to tyramine in assays measuring serotonin‐dependent pharyngeal pumping. These are the first reported functions for SER‐2. These results suggest that C. elegans contains tyramine receptors, that individual SER‐2 isoforms may differ significantly in their sensitivity to other physiologically relevant biogenic amines, such as octopamine (OA), and that tyraminergic signaling may be important in the regulation of key processes in nematodes.
Low nNOS protein in the locus coeruleus in major depression
Authors: Karolewicz B. , Szebeni K. , Stockmeier C. A. , Konick L. , Overholser J. C. , Jurjus G. , Roth B. L. , Ordway G. A. 
Published: November 2004

AbstractDisruptions of glutamatergic and noradrenergic signaling have been postulated to occur in depressive disorders. Glutamate provides excitatory input to the noradrenergic locus coeruleus (LC). In this study, the location of immunoreactivity against neuronal nitric oxide synthase (nNOS), an intracellular mediator of glutamate receptor activation, was examined in the normal human LC, and potential changes in nNOS immunoreactivity that might occur in major depression were evaluated. Tissue containing LC, and a non‐limbic, LC projection area (cerebellum) was obtained from 11 to 12 matched pairs of subjects with major depression and control subjects lacking major psychiatric diagnoses. In the LC region, nNOS immunoreactivity was found in large neuromelanin‐containing neurons, small neurons lacking neuromelanin, and glial cells. Levels of nNOS immunoreactivity were significantly lower in the LC (− 44%, p < 0.05), but not in the cerebellum, when comparing depressed with control subjects. nNOS levels were positively correlated with brain pH values in depressed, but not control, subjects in both brain regions. Low levels of nNOS in the LC may reflect altered excitatory input to this nucleus in major depression. However, pH appears to effect preservation of nNOS immunoreactivity in subjects with depression. This factor may contribute, in part, to low levels of nNOS in depression.
Curcumin, the active constituent of turmeric, inhibits amyloid peptide‐induced cytochemokine gene expression and CCR5‐mediated chemotaxis of THP‐1 monocytes by modulating early growth response‐1 transcription factor
Authors: Giri Ranjit K. , Rajagopal Vikram , Kalra Vijay K. 
Published: November 2004

AbstractEpidemiological studies show reduced risk of Alzheimer's disease (AD) among patients using non‐steroidal inflammatory drugs (NSAID) indicating the role of inflammation in AD. Studies have shown a chronic CNS inflammatory response associated with increased accumulation of amyloid peptide and activated microglia in AD. Our previous studies showed that interaction of Aβ1−40 or fibrilar Aβ1−42 caused activation of nuclear transcription factor, early growth response‐1 (Egr‐1), which resulted in increased expression of cytokines (TNF‐α and IL‐1β) and chemokines (MIP‐1β, MCP‐1 and IL‐8) in monocytes. We determined whether curcumin, a natural product known to have anti‐inflammatory properties, suppressed Egr‐1 activation and concomitant expression of cytochemokines. We show that curcumin (12.5–25 µm) suppresses the activation of Egr‐1 DNA‐binding activity in THP‐1 monocytic cells. Curcumin abrogated Aβ1−40‐induced expression of cytokines (TNF‐α and IL‐1β) and chemokines (MIP‐1β, MCP‐1 and IL‐8) in both peripheral blood monocytes and THP‐1 cells. We found that curcumin inhibited Aβ1−40‐induced MAP kinase activation and the phosphorylation of ERK‐1/2 and its downstream target Elk‐1. We observed that curcumin inhibited Aβ1−40‐induced expression of CCR5 but not of CCR2b in THP‐1 cells. This involved abrogation of Egr‐1 DNA binding in the promoter of CCR5 by curcumin as determined by: (i) electrophoretic mobility shift assay, (ii) transfection studies with truncated CCR5 gene promoter constructs, and (iii) chromatin immunoprecipitation analysis. Finally, curcumin inhibited chemotaxis of THP‐1 monocytes in response to chemoattractant. The inhibition of Egr‐1 by curcumin may represent a potential therapeutic approach to ameliorate the inflammation and progression of AD.
Functional characterization of mouse α4β2 nicotinic acetylcholine receptors stably expressed in HEK293T cells
Authors: Karadsheh Mark S. , Shah M. Salman , Tang Xin , Macdonald Robert L. , Stitzel Jerry A. 
Published: November 2004

AbstractMouse α4β2 nicotinic acetylcholine receptors (nAchRs) were stably expressed in HEK293T cells. The function of this stable cell line, termed mmα4β2, was assessed using an aequorin‐based luminescence method that measures agonist‐evoked changes in intracellular calcium. Agonist‐elicited changes in intracellular calcium were due primarily to direct entry of calcium through the α4β2 channel, although release of calcium from intracellular stores contributed ˜ 28% of the agonist‐evoked response. Agonist pharmacologies were very similar between the mmα4β2 cells and most cell lines that stably express human α4β2 nAchRs. Based on agonist profiles and sensitivity to the antagonist dihydro‐β‐erythroidine (DHβE), the predominant α4β2 nAchR expressed in the mmα4β2 cells exhibits a pharmacology that most resembles the DHβE‐sensitive component of 86Rb+ efflux from mouse brain synaptosomes. However, when evaluated with the aequorin assay, the mmα4β2 nAchR was found to be atypically sensitive to blockade by the presumed α7‐selective antagonist methyllycaconitine (MLA), exhibiting an IC50 value of 31 ± 0.1 nm. Similar IC50 values have been reported for the MLA inhibition of nicotine‐stimulated dopamine release, a response that is mediated by β2‐subunit‐containing nAchRs and not α7‐subunit‐containing nAchRs. Consequently, at low nanomolar concentrations, MLA may not be as selective for α7‐containing nAchRs as previously thought.
Proteasome inhibition increases DNA and RNA oxidation in astrocyte and neuron cultures
Authors: Ding Qunxing , Dimayuga Edgardo , Markesbery William R. , Keller Jeffrey N. 
Published: November 2004

AbstractIncreased levels of nucleic acid oxidation have been described as part of normal brain aging and have been demonstrated to occur in multiple neurological disorders. The basis for increased nucleic acid oxidation in each of these conditions is presently unknown. Proteasome inhibition occurs in a host of neurodegenerative conditions and likely contributes to increased levels of oxidative damage and neurotoxicity. In the present study we demonstrate for the first time the ability of proteasome inhibition to increase the level of nucleic acid oxidation in primary neuron and astrocyte cultures. Administration of proteasome inhibitors (MG262, MG115) at concentrations that do not induce neuron death in the first 24 h of treatment, dramatically increase the levels of 8‐hydroxy‐2′‐deoxyguanosine (8‐OHdG) and 8‐hydroxyguanosine (8OHG) immunoreactivity in both cell types. Neurons underwent larger increases in nucleic acid oxidation compared to astrocyte cultures. While both DNA and RNA oxidation were observed following proteasome inhibition, RNA appeared to undergo a greater degree of oxidation than DNA. Both 18S and 28S ribosomal RNA were dramatically decreased following proteasome inhibition. Interestingly, an accumulation of unprocessed and/or cross‐linked RNA species was observed following proteasome inhibition. Taken together, these data indicate the ability of proteasome inhibition to increase the levels of nucleic acid oxidation in both neurons and astrocytes, and suggest that proteasome inhibition may have deleterious effects on transcription and translation in both neurons and glia.
Pathophysiological concentrations of amyloid β proteins directly inhibit rat brain and recombinant human type II phosphatidylinositol 4‐kinase activity
Authors: Wu Bo , Kitagawa Kaori , Zhang Nan‐Yan , Liu Bing , Inagaki Chiyoko 
Published: November 2004

AbstractWe previously found that pathophysiological concentrations (≤ 10 nm) of an amyloid β protein (Aβ25–35) reduced the plasma membrane phosphatidylinositol monophosphate level in cultured rat hippocampal neurons with a decrease in phosphatidylinositol 4‐monophosphate‐dependent Cl–‐ATPase activity. As this suggested an inhibitory effect of Aβ25–35 on plasma membrane phosphatidylinositol 4‐kinase (PI4K) activity, in vitro effects of Aβs on PI4K activity was examined using rat brain subcellular fractions and recombinant human type II PI4K (PI4KII). Aβ25–35 (10 nm) inhibited PI4KII activity, but neither PI 3‐kinase (PI3K) nor type III PI4K (PI4KIII) activity, in microsomal fractions, while 100 nm Aβ25–35 inhibited PI3K activity in mitochondrial fractions. In plasma membrane‐rich fractions, Aβs (> 0.5 nm) dose‐dependently inhibited PI4KII activity, the maximal inhibition to 77–87% of control being reached around 10 nm of Aβs without significant changes in apparent Km values for ATP and PI, suggesting non‐competitive inhibition by Aβs. The inhibition by 10 nm Aβ25–35 was reversible. In recombinant human PI4KIIα, inhibition profiles of Aβs were similar to those in rat brain plasma membranes. Therefore, pathophysiological concentrations of Aβs directly and reversibly inhibited plasma membrane PI4KII activity, suggesting that plasma membrane PI4KII is a target of Aβs in the pathogenesis of Alzheimer's disease.
Application of magnetically isolated rat retinal vascular endothelial cells for the determination of transporter gene expression levels at the inner blood–retinal barrier
Authors: Tomi Masatoshi , Hosoya Ken‐ichi 
Published: November 2004

AbstractThe purpose of the present study was to quantify transporter gene levels at the inner blood–retinal barrier (inner BRB) using a combination of magnetic isolation method for rat retinal vascular endothelial cells (RVEC) and real‐time quantitative PCR analysis. The transcript levels of CD31, Tie‐2, claudin‐5, occludin, Jam‐1, mdr1a, oatp2, and oatp14 in the RVEC fraction were more than 100‐fold greater than those in the non‐RVEC fraction, suggesting that these genes are predominantly expressed at the inner BRB. The transcript levels of GLUT1 and MCT1 in the RVEC fraction were the most abundant in the respective transporter family, suggesting that GLUT1 and MCT1 play a predominant role in d‐glucose and monocarboxylate transport, respectively, at the inner BRB. In conclusion, application of magnetically isolated RVEC is able to determine transporter gene levels at the inner BRB thereby increasing our understanding of inner BRB functions at a molecular level.
Prospective Association Between Low and High Total and Low‐Density Lipoprotein Cholesterol and Coronary Heart Disease in Elderly Men
Authors: Curb J. David , Abbott Robert D. , Rodriguez Beatriz L. , Masaki Kamal , Popper Jordan , Chen Randi , Petrovitch Helen , Blanchette Patricia , Schatz Irwin , Yano Katsuhiko 
Published: November 2004

Objectives:To examine the relationship between total cholesterol (TC) and low‐density lipoprotein cholesterol (LDL‐C) and the incidence of coronary heart disease (CHD) in elderly men.Design:Prospective.Setting:Population based.Participants:A sample of 2,424, Japanese‐American men aged 71 to 93 was used.Measurements:Six years of data on incident fatal plus nonfatal CHD were examined.Results:Analysis revealed a significant U‐shaped relationship between age‐adjusted CHD rates and both TC and LDL‐C. The ranges of TC and LDL‐C with the lowest risk of CHD were 200 to 219 mg/dL and 120 to 139 mg/dL, respectively. As cholesterol concentrations declined and increased beyond these ranges, the risk of CHD increased. These U‐shaped relationships remained significant after adjusting for age and other risk factors.Conclusion:The U‐shaped associations between TC and LDL‐C and CHD imply a complex relationship between lipids and CHD in late life. The results indicate that elevated lipid levels should continue to be treated in healthy elderly individuals, as they are in those who are younger, although pharmacologically lowering lipids to excessively low levels in the elderly may warrant further study, as does the contribution of subclinical frailty to the relationship of lipids to CHD risk.
Vision Impairment and Combined Vision and Hearing Impairment Predict Cognitive and Functional Decline in Older Women
Authors: Lin Michael Y. , Gutierrez Peter R. , Stone Katie L. , Yaffe Kristine , Ensrud Kristine E. , Fink Howard A. , Sarkisian Catherine A. , Coleman Anne L. , Mangione Carol M. 
Published: November 2004

Objectives: To determine the association between vision and hearing impairment and subsequent cognitive and functional decline in community‐residing older women.Design: Prospective cohort study.Setting: Four metropolitan areas of the United States.Participants: A total of 6,112 women aged 69 and older participating in the Study of Osteoporotic Fractures (SOF) between 1992 and 1994.Measurements: Five thousand three hundred forty‐five participants had hearing measured, 1,668 had visual acuity measured, and 1,636 had both measured. Visual impairment was defined as corrected vision worse than 20/40. Hearing impairment was defined as the inability to hear a tone of 40 dB or greater at 2,000 hertz. Participants completed the modified Mini‐Mental State Examination and/or a functional status assessment at baseline and follow‐up. Cognitive and functional decline were defined as the amount of decline from baseline to follow‐up that exceeded the observed average change in scores by at least 1 standard deviation.Results: About one‐sixth (15.7%) of the sample had cognitive decline; 10.1% had functional decline. In multivariate models adjusted for sociodemographic characteristics and chronic conditions, vision impairment at baseline was associated with cognitive (odds ratio (OR)=1.78, 95% confidence interval (CI)=1.21–2.61) and functional (OR=1.79, 95% CI=1.15–2.79) decline. Hearing impairment was not associated with cognitive or functional decline. Combined impairment was associated with the greatest odds for cognitive (OR=2.19, 95% CI=1.26–3.81) and functional (OR=1.87, 95% CI=1.01–3.47) decline.Conclusion: Sensory impairment is associated with cognitive and functional decline in older women. Studies are needed to determine whether treatment of vision and hearing impairment can decrease the risk for cognitive and functional decline.