bluuebunny/crossref_metadata_2025 huggingface dataset:
LONG-PULSE LASER-ASSISTED SURFACE MODIFICATION OF AN IMAGING FIBER FOR FABRICATION OF INTEGRATED FIBER MICROLENSES
Authors: MURUKESHAN V. M. , KHIRMAN M. A. , ZHENG H. Y. , TAN J. L.
Published: July 2004

This paper discusses the results obtained with a long pulse laser (such as a CO2 laser) assisted shaping of microspherical lenses at the end face of a specialty image fiber. The 600-μm-diameter image fiber consists of 15 000 pixels (individual fibers) with a spatial resolution of 267/mm. When laser-assisted heating is induced at the surface of the fiber tip, it tends to become spherical in shape due to surface tension. The curvature formed at the surface will act as the microspherical lens. The effects of the laser repetition rate and irradiation time on the surface finish and curvature of the shaped lens are illustrated in this paper.
MICROCRACKS IN ~ 100 MeV Si7+-ION-IRRADIATED p-SILICON SURFACES
Authors: SINHA O. P. , SRIVASTAVA P. C. , GANESAN V.
Published: July 2004

The p-silicon surfaces have been irradiated with ~ 100 MeV Si 7+ions to a fluence of 2.2×1013 ions cm -2, and surface morphology has been studied with atomic force microscopy (AFM). Interesting features of cracks of ~ 47 nm in depth and ~ 103 nm in width on the irradiated surfaces have been observed. The observed features seemed to have been caused by the irradiation-induced stress in the irradiated regions of the target surface.
SPIN POLARIZATION OF ELECTRONS BY DEPOSITING HYBRID FERROMAGNETIC STRIPES ON A SEMICONDUCTOR HETEROSTRUCTURE
Authors: LU MAO-WANG
Published: July 2004

One type of combined magnetically modulated nanostructures is proposed that can be experimentally realized by depositing two hybrid ferromagnetic stripes on the surface of a semiconductor heterostructure. Since these two stripes induce different magnetic barriers, the electron transmission and the conductance of nanostructure are strongly dependent upon the electronic spins. Thus, in this kind of hybrid magnetic nanostructures, electrons show up a considerable spin polarization effect, which provides an alternative approach to realization of spin-polarized electrons into semiconductors and may be of practical importance for spin-based nanodevice applications.
MICROBIAL DIVERSITY IN SOIL: Selection of Microbial Populations by Plant and Soil Type and Implications for Disease Suppressiveness
Authors: Garbeva P. , van Veen J.A. , van Elsas J.D.
Published: July 2004

▪ Abstract  An increasing interest has emerged with respect to the importance of microbial diversity in soil habitats. The extent of the diversity of microorganisms in soil is seen to be critical to the maintenance of soil health and quality, as a wide range of microorganisms is involved in important soil functions. This review focuses on recent data relating how plant type, soil type, and soil management regime affect the microbial diversity of soil and the implication for the soil's disease suppressiveness. The two main drivers of soil microbial community structure, i.e., plant type and soil type, are thought to exert their function in a complex manner. We propose that the fact that in some situations the soil and in others the plant type is the key factor determining soil microbial diversity is related to the complexity of the microbial interactions in soil, including interactions between microorganisms and soil and microorganisms and plants. A conceptual framework, based on the relative strengths of the shaping forces exerted by plant and soil versus the ecological behavior of microorganisms, is proposed.
TYPE III SECRETION SYSTEM EFFECTOR PROTEINS: Double Agents in Bacterial Disease and Plant Defense
Authors: Alfano James R. , Collmer Alan
Published: July 2004

▪ Abstract  Many phytopathogenic bacteria inject virulence effector proteins into plant cells via a Hrp type III secretion system (TTSS). Without the TTSS, these pathogens cannot defeat basal defenses, grow in plants, produce disease lesions in hosts, or elicit the hypersensitive response (HR) in nonhosts. Pathogen genome projects employing bioinformatic methods to identify TTSS Hrp regulon promoters and TTSS pathway targeting signals suggest that phytopathogenic Pseudomonas, Xanthomonas, and Ralstonia spp. harbor large arsenals of effectors. The Hrp TTSS employs customized cytoplasmic chaperones, conserved export components in the bacterial envelope (also used by the TTSS of animal pathogens), and a more specialized set of TTSS-secreted proteins to deliver effectors across the plant cell wall and plasma membrane. Many effectors can act as molecular double agents that betray the pathogen to plant defenses in some interactions and suppress host defenses in others. Investigations of the functions of effectors within plant cells have demonstrated the plasma membrane and nucleus as subcellular sites for several effectors, revealed some effectors to possess cysteine protease or protein tyrosine phosphatase activity, and provided new clues to the coevolution of bacterium-plant interactions.
The Accidental Plant Pathologist
Authors: Vidaver Anne K.
Published: July 2004

▪ Abstract  This article presents the experiences of a woman in academic plant pathology from the 1950s to today. Topics include the social climate for women in science, personal and professional developments and research discoveries, public policy issues in agriculture and biotechnology affecting plant pathology, and projections for the future of plant pathology.
Real-time three-dimensional imaging of lipid signal transduction: apical membrane insertion of epithelial Na+ channels
Authors: Blazer-Yost Bonnie L. , Vahle Judith C. , Byars Jason M. , Bacallao Robert L.
Published: July 2004

In the distal tubule, Na+ resorption is mediated by epithelial Na+ channels (ENaC). Hormones such as aldosterone, vasopressin, and insulin modulate ENaC membrane targeting, assembly, and/or kinetic activity, thereby regulating salt and water homeostasis. Insulin binds to a receptor on the basal membrane to initiate a signal transduction cascade that rapidly results in an increase in apical membrane ENaC. Current models of this signaling pathway envision diffusion of signaling intermediates from the basal to the apical membrane. This necessitates diffusion of several high-molecular-weight signaling elements across a three-dimensional space. Transduction of the insulin signal involves the phosphoinositide pathway, but how and where this lipid-based signaling pathway controls ENaC activity is not known. We used tagged channels, biosensor lipid probes, and intravital imaging to investigate the role of lipids in insulin-stimulated Na+ flux. Insulin-stimulated delivery of intracellular ENaC to apical membranes was concurrent with plasma membrane-limited changes in lipid composition. Notably, in response to insulin, phosphatidylinositol 3,4,5-trisphosphate (PIP3) formed in the basolateral membrane, rapidly diffused within the bilayer, and crossed the tight junction to enter the apical membrane. This novel signaling pathway takes advantage of the fact that the lipids of the plasma membrane's inner leaflet are not constrained by the tight junction. Therefore, diffusion of PIP3 as a signal transduction intermediate occurs within a planar surface, thus facilitating swift responses and confining and controlling the signaling pathway.
Effect of creatine on contractile force and sensitivity in mechanically skinned single fibers from rat skeletal muscle
Authors: Murphy Robyn M. , Stephenson D. George , Lamb Graham D.
Published: July 2004

Increasing the intramuscular stores of total creatine [TCr = creatine (Cr) + creatine phosphate (CrP)] can result in improved muscle performance during certain types of exercise in humans. Initial uptake of Cr is accompanied by an increase in cellular water to maintain osmotic balance, resulting in a decrease in myoplasmic ionic strength. Mechanically skinned single fibers from rat soleus (SOL) and extensor digitorum longus (EDL) muscles were used to examine the direct effects on the contractile apparatus of increasing [Cr], increasing [Cr] plus decreasing ionic strength, and increasing [Cr] and [CrP] with no change in ionic strength. Increasing [Cr] from 19 to 32 mM, accompanied by appropriate increases in water to maintain osmolality, had appreciable beneficial effects on contractile apparatus performance. Compared with control conditions, both SOL and EDL fibers showed increases in Ca2+ sensitivity (+0.061 ± 0.004 and +0.049 ± 0.009 pCa units, respectively) and maximum Ca2+-activated force (to 104 ± 1 and 105 ± 1%, respectively). In contrast, increasing [Cr] alone had a small inhibitory effect. When both [Cr] and [CrP] were increased, there was virtually no change in Ca2+ sensitivity of the contractile apparatus, and maximum Ca2+-activated force was ∼106 ± 1% compared with control conditions in both SOL and EDL fibers. These results suggest that the initial improvement in performance observed with Cr supplementation is likely due in large part to direct effects of the accompanying decrease in myoplasmic ionic strength on the properties of the contractile apparatus.
Diurnal variations in the responsiveness of cardiac and skeletal muscle to fatty acids
Authors: Stavinoha Melissa A. , RaySpellicy Joseph W. , Hart-Sailors Mary L. , Mersmann Harry J. , Bray Molly S. , Young Martin E.
Published: August 2004

Cardiac and skeletal muscle both respond to elevated fatty acid availability by increasing fatty acid oxidation, an effect mediated in large part by peroxisome proliferator-activated receptor-α (PPARα). We hypothesized that cardiac and skeletal muscle alter their responsiveness to fatty acids over the course of the day, allowing optimal adaptation when availability of this substrate increases. In the current study, pyruvate dehydrogenase kinase 4 ( pdk4) was utilized as a representative PPARα-regulated gene. Opposing diurnal variations in pdk4 expression were observed in cardiac and skeletal muscle isolated from the ad libitum-fed rat; pdk4 expression peaked in the middle of the dark and light phases, respectively. Elevation of circulating fatty acid levels by high-fat feeding, fasting, and streptozotocin-induced diabetes increased pdk4 expression in both heart and soleus muscle. Highest levels of induction were observed during the dark phase, regardless of muscle type or intervention. Specific activation of PPARα with WY-14643 rapidly induced pdk4 expression in heart and soleus muscle. Highest levels of induction were again observed during the dark phase. The same pattern of induction was observed for the PPARα-regulated genes malonyl-CoA decarboxylase and uncoupling protein 3. Investigation into the potential mechanism(s) for these observations exposed a coordinated upregulation of transcriptional activators of the PPARα system during the night, with a concomitant downregulation of transcriptional repressors in both muscle types. In conclusion, responsiveness of cardiac and skeletal muscle to fatty acids exhibits a marked diurnal variation. These observations have important physiological and pathophysiological implications, ranging from experimental design to pharmacological treatment of patients.
Alterations in cell-adhesive and migratory properties of proximal tubule and collecting duct cells from bcl-2 −/− mice
Authors: Ziehr Jacqueline , Sheibani Nader , Sorenson Christine M.
Published: August 2004

Bcl-2 protects cells from apoptosis initiated by a variety of stimuli including loss of cell adhesion. Bcl-2 −/− mice develop renal hypoplastic/cystic dysplasia with renal cyst formation coinciding with renal maturation in normal mice. To gain a better understanding of the role cell-adhesive mechanisms play during renal maturation, we generated proximal tubule and collecting duct cell lines from postnatal day 10 ( P10) and P20 bcl-2 +/+ and bcl-2 −/− mice. Very little is known about the role cell-adhesive and migratory mechanisms play during renal maturation. We observed that modulation of cell-adhesive properties, which normally occur in a nephron segment-specific manner during renal maturation, and cell migration were altered in cells from bcl-2 −/− mice. Enhanced migration of bcl-2 −/− proximal tubule cells in a scratch wound assay was completely inhibited by incubation with PP1 (Src inhibitor) and moderately affected by incubation with SB-203580 (p38 inhibitor). These cells expressed increased levels of fibronectin and had numerous central focal adhesions. P20 bcl-2 −/− proximal tubule cells adhered to fibronectin but adhered poorly to collagen, vitronectin, or laminin. Collecting duct cells, similar to proximal tubule cells from bcl-2 −/− mice, demonstrated enhanced migration in a scratch wound assay that was inhibited by incubation with PP1. Migration of these cells was moderately affected by incubation with PD-98059 (MEK inhibitor) or LY-294002 (PI3 kinase inhibitor), whereas incubation with SB-203580 had no effect. P10 bcl-2 −/− collecting duct cells also expressed increased levels of fibronectin but decreased levels of thrombospondin-1 and demonstrated precocious binding to fibronectin and vitronectin compared with bcl-2 +/+ cells. The ability of P20 bcl-2 +/+ collecting duct cells to adhere to fibronectin and vitronectin corresponded with a decline in thrombospondin-1 expression. Therefore, alterations in cell-adhesive and migratory characteristics may be an early indicator of aberrant renal epithelial cell differentiation.
Involvement of cytosolic Cl− in osmoregulation of α-ENaC gene expression
Authors: Niisato Naomi , Eaton Douglas C. , Marunaka Yoshinori
Published: August 2004

Hypotonicity stimulates transepithelial Na+ reabsorption in renal A6 cells, but the mechanism for this stimulation is not fully understood. In the present study, we found that hypotonicity stimulated Na+ reabsorption through increases in mRNA expression of the α-subunit of the epithelial Na+ channel (α-ENaC). Hypotonicity decreases cytosolic Cl− concentration; therefore, we hypothesized that hypotonicity-induced decreases in cytosolic Cl− concentration could act as a signal to regulate Na+ reabsorption through changes in α-ENaC mRNA expression. Treatment with the flavone apigenin, which activates the Na+-K+-2Cl− cotransporter and increases cytosolic Cl− concentration, markedly suppressed the hypotonicity-induced increase in α-ENaC mRNA expression. On the other hand, blockade of the Na+-K+-2Cl− cotransporter decreases cytosolic Cl− concentration and increased α-ENaC mRNA expression and Na+ reabsorption. Blocking Cl− channels with 5-nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB) inhibited the hypotonicity-induced decrease in cytosolic Cl− concentration and suppressed the hypotonicity-induced increase in α-ENaC mRNA expression. Coapplication of NPPB and apigenin synergistically suppressed α-ENaC mRNA expression. Thus, in every case, changes in cytosolic Cl− concentration were associated with changes in α-ENaC mRNA expression and changes in Na+ reabsorption: decreases in cytosolic Cl− concentration increased α-ENaC mRNA and increased Na+ reabsorption, whereas increases in cytosolic Cl− concentration decreased α-ENaC mRNA and decreased Na+ reabsorption. These findings support the hypothesis that changes in cytosolic Cl− concentration are an important and novel signal in hypotonicity-induced regulation of α-ENaC expression and Na+ reabsorption.
Effect of endogenous angiotensin II on the frequency response of the renal vasculature
Authors: DiBona Gerald F. , Sawin Linda L.
Published: August 2004

The renal vasculature functions as an efficient low-pass filter of the multiple frequencies contained within renal sympathetic nerve activity. This study examined the effect of angiotensin II on the frequency response of the renal vasculature. Physiological changes in the activity of the endogenous renin-angiotensin system were produced by alterations in dietary sodium intake. The frequency response of the renal vasculature was evaluated using pseudorandom binary sequence renal nerve stimulation, and the role of angiotensin II was evaluated by the administration of the angiotensin II AT1-receptor antagonist losartan. In low-sodium-diet rats with increased renin-angiotensin system activity, losartan steepened the renal vascular frequency response (i.e., greater attenuation); this was not seen in normal- or high-sodium-diet rats with normal or decreased renin-angiotensin system activity. Analysis of the transfer function from arterial pressure to renal blood flow, i.e., dynamic autoregulation, showed that the tubuloglomerular feedback but not the myogenic component was enhanced in low- and normal- but not in high-sodium-diet rats and that this was reversed by losartan administration. Thus physiological increases in endogenous renin-angiotensin activity inhibit the renal vascular frequency response to renal nerve stimulation while selectively enhancing the tubuloglomerular feedback component of dynamic autoregulation of renal blood flow.
PDZ binding motif-dependent localization of K+ channel on the basolateral side in distal tubules
Authors: Tanemoto Masayuki , Abe Takaaki , Onogawa Tohru , Ito Sadayoshi
Published: August 2004

Kir5.1, a nonfunctional inwardly rectifying K+ channel by itself, can form functional channels by assembling with other proteins. We previously showed that Kir5.1 assembled with Kir4.1 and functioned as an acid-base regulator in the kidney. In this study, we examined the intrarenal distribution of Kir5.1 by RT-PCR analysis on dissected nephron segments and immunohistochemical analysis with the specific anti-Kir5.1 antibody. Strong expression of Kir5.1 was detected in distal convoluted tubules, and weak expression was also detected in thick ascending limb of Henle's loop. Colocalization of Kir5.1 with Kir4.1 indicated expression of Kir5.1/Kir4.1 heteromer in these nephron segments. In a renal epithelial cell line, Madin-Darby canine kidney cells, heteromer formation with Kir4.1 changed the localization of Kir5.1 from intracellular components to the cell surface. The COOH-terminal cytoplasmic portion that includes the PDZ binding motif of Kir4.1 was responsible for this intracellular localization. These data suggest the signals on the COOH terminus of Kir4.1, including PDZ binding motif, determine the intracellular localization of Kir5.1/Kir4.1 heteromer in distal tubules.
3, 3′, 4, 4′, 5‐Pentachlorobiphenyl Inhibits Drug Efflux Through P‐Glycoprotein in KB‐3 Cells Expressing Mutant Human P‐Glycoprotein
Authors: Fujise Hiroshi , Sasawatari Shigemi , Annoura Takeshi , Ikeda Teruo , Ueda Kazumitsu
Published: July 2004

The effects on the drug efflux of 3, 3′, 4, 4′, 5‐pentachlorobiphenyl (PCB‐126), the most toxic of all coplanar polychlorinated biphenyls (Co‐PCBs), were examined in KB‐3 cells expressing human wild‐type and mutant P‐glycoprotein in which the 61st amino acid was substituted for serine or phenylalanine (KB3‐Phe61). In the cells expressing P‐glycoproteins, accumulations of vinblastine and colchicine decreased form 85% to 92% and from 62% to 91%, respectively, and the drug tolerances for these chemicals were increased. In KB3‐Phe61, the decreases in drug accumulation were inhibited by adding PCB‐126 in a way similar to that with cyclosporine A: by adding 1 μM PCB‐126, the accumulations of vinblastine and colchicine increased up to 3.3‐ and 2.3‐fold, respectively. It is suggested that PCB‐126 decreased the drug efflux by inhibiting the P‐glycoprotein in KB3‐Phe61. Since there were various P‐glycoproteins and many congeners of Co‐PCBs, this inhibition has to be considered a new cause of the toxic effects of Co‐PCBs.
The Developing Country Reactions to Biomedical Techniques and Plant Biotechnology: The Tunisian Experience
Authors: Tebourski Fethi , Ben Ammar-Elgaaied Amel
Published: July 2004

In the present study we present the conditions offered to biotechnology development in Tunisia and we compare three main biotechnology applications which raise ethical and health problems: organ transplant, assisted reproductive techniques, and genetically modified organisms. We try to identify factors that have allowed success of the first two applications and failure of the latter. Conditions offered to biotechnology in other African countries are also discussed.
Overexpression of the NOTCH ligand JAG2 in malignant plasma cells from multiple myeloma patients and cell lines
Authors: Houde Christiane , Li Yulin , Song Lynda , Barton Kevin , Zhang Qing , Godwin John , Nand Sucha , Toor Amir , Alkan Serhan , Smadja N. Veronique , Avet-Loiseau Hervé , Lima Carmen S. , Miele Lucio , Coignet Lionel J.
Published: August 2004

The NOTCH ligand, JAG2, was found to be overexpressed in malignant plasma cells from multiple myeloma (MM) patients and cell lines but not in nonmalignant plasma cells from tonsils, bone marrow from healthy individuals, or patients with other malignancies. In addition, JAG2 overexpression was detected in 5 of 5 patients with monoclonal gammopathy of undetermined significance (MGUS), an early phase of myeloma disease progression. This overexpression appears to be a consequence of hypomethylation of the JAG2 promoter in malignant plasma cells. An in vitro coculture assay was used to demonstrate that JAG2 induced the secretion of interleukin-6 (IL-6), vascular endothelial growth factor (VEGF), and insulin-like growth factor-1 (IGF-1) in stromal cells. Further, the induction of IL-6 secretion was blocked in vitro by interference with anti–Notch-1 monoclonal antibodies raised against the binding sequence of Notch-1 with JAG2. Taken together, these results indicate that JAG2 overexpression may be an early event in the pathogenesis of multiple myeloma involving IL-6 production.
Duration of immunosuppressive treatment for chronic graft-versus-host disease
Authors: Stewart Betty L. , Storer Barry , Storek Jan , Deeg H. Joachim , Storb Rainer , Hansen John A. , Appelbaum Frederick R. , Carpenter Paul A. , Sanders Jean E. , Kiem Hans-Peter , Nash Richard A. , Petersdorf Effie W. , Moravec Carina , Morton A. James , Anasetti Claudio , Flowers Mary E. D. , Martin Paul J.
Published: August 2004

Chronic graft-versus-host disease (GVHD) requires long-term immunosuppressive therapy after hematopoietic cell transplantation. We retrospectively analyzed a cohort of 751 patients with chronic GVHD to identify characteristics associated with the duration of immunosuppressive treatment. Among the 274 patients who discontinued immunosuppressive therapy after resolution of chronic GVHD before recurrent malignancy or death, the median duration of treatment was 23 months. Results of a multivariable model showed that treatment was prolonged in patients who received peripheral blood cells, in male patients with female donors, in those with graft-versus-host HLA mismatching, and in those with hyperbilirubinemia or multiple sites affected by chronic GHVD at the onset of the disease. Nonrelapse mortality was increased among patients with HLA mismatching or hyperbilirubinemia but not among those with other risk factors associated with prolonged treatment for chronic GVHD. Nonrelapse mortality was also increased in older patients and those with older donors, in patients with platelet counts less than 100 000/μL or progressive onset of chronic GVHD from acute GVHD, and in those receiving higher doses of prednisone immediately before the diagnosis of chronic GVHD. After the dose of prednisone was taken into account, progressive onset was not associated with an increased risk of nonrelapse mortality.
IL-8 responsiveness defines a subset of CD8 T cells poised to kill
Authors: Hess Christoph , Means Terry K. , Autissier Patrick , Woodberry Tonia , Altfeld Marcus , Addo Marylyn M. , Frahm Nicole , Brander Christian , Walker Bruce D. , Luster Andrew D.
Published: August 2004

CD8 T cells play a key role in host defense against intracellular pathogens. Efficient migration of these cells into sites of infection is therefore intimately linked to their effector function. The molecular mechanisms that control CD8 T-cell trafficking into sites of infection and inflammation are not well understood, but the chemokine/chemokine receptor system is thought to orchestrate this process. Here we systematically examined the chemokine receptor profile expressed on human CD8 T cells. Surprisingly, we found that CXC chemokine receptor 1 (CXCR1), the predominant neutrophil chemokine receptor, defined a novel interleukin-8/CXC ligand 8 (IL-8/CXCL8)–responsive CD8 T-cell subset that was enriched in perforin, granzyme B, and interferon-γ (IFNγ), and had high cytotoxic potential. CXCR1 expression was down-regulated by antigen stimulation both in vitro and in vivo, suggesting antigen-dependent shaping of the migratory characteristics of CD8 T cells. On virus-specific CD8 T cells from persons with a history of Epstein-Barr virus (EBV) and influenza infection, CXCR1 expression was restricted to terminally differentiated effector memory cells. In HIV-1 infection, CXCR1-expressing HIV-1–specific CD8 T cells were present only in persons who were able to control HIV-1 replication during structured treatment interruptions. Thus, CXCR1 identifies a subset of CD8 T cells poised for immediate cytotoxicity and early recruitment into sites of innate immune system activation.
Inhibition of thrombin generation by protein S at low procoagulant stimuli: implications for maintenance of the hemostatic balance
Authors: Seré Kristin M. , Rosing Jan , Hackeng Tilman M.
Published: August 2004

The activated protein C (APC)–independent anticoagulant activity of protein S on tissue factor–induced thrombin generation was quantified in plasma. In absence of APC, protein S significantly decreased the endogenous thrombin potential (ETP) in a concentration-dependent manner. The APC-independent anticoagulant activity of protein S in plasma was not affected by phospholipid concentrations but strongly depended on tissue factor concentrations: protein S inhibited the ETP from 6% at 140 pM tissue factor to 74% at 1.4 pM tissue factor. Plasma with both 60% protein S and 140% prothrombin showed an ETP of 240% compared to normal plasma, suggesting an APC-independent protective role of protein S in the development of thrombosis as a result of protein S deficiency and the prothrombin-G20210A mutation. At high tissue-factor concentrations, protein S hardly expressed APC-independent anticoagulant activity but exerted potent APC-cofactor activity when thrombomodulin or APC were added to plasma. Neutralization of protein S under these conditions resulted in a 20-fold reduction of the anticoagulant activity of APC. The present study shows that protein S effectively regulates coagulation at 2 levels: at low procoagulant stimuli, protein S maintains the hemostatic balance by directly inhibiting thrombin formation, and at high procoagulant stimuli, protein S restores the hemostatic balance via its APC-cofactor activity.
C-type lectin-like domains in Fugu rubripes
Authors: Zelensky Alex N , Gready Jill E
Published: August 2004

Background

Members of the C-type lectin domain (CTLD) superfamily are metazoan proteins functionally important in glycoprotein metabolism, mechanisms of multicellular integration and immunity. Three genome-level studies on human, C. elegans and D. melanogaster reported previously demonstrated almost complete divergence among invertebrate and mammalian families of CTLD-containing proteins (CTLDcps).

Results

We have performed an analysis of CTLD family composition in Fugu rubripes using the draft genome sequence. The results show that all but two groups of CTLDcps identified in mammals are also found in fish, and that most of the groups have the same members as in mammals. We failed to detect representatives for CTLD groups V (NK cell receptors) and VII (lithostathine), while the DC-SIGN subgroup of group II is overrepresented in Fugu. Several new CTLD-containing genes, highly conserved between Fugu and human, were discovered using the Fugu genome sequence as a reference, including a CSPG family member and an SCP-domain-containing soluble protein. A distinct group of soluble dual-CTLD proteins has been identified, which may be the first reported CTLDcp group shared by invertebrates and vertebrates. We show that CTLDcp-encoding genes are selectively duplicated in Fugu, in a manner that suggests an ancient large-scale duplication event. We have verified 32 gene structures and predicted 63 new ones, and make our annotations available through a distributed annotation system (DAS) server http://anz.anu.edu.au:8080/Fugu_rubripes/ and their sequences as additional files with this paper.

Conclusions

The vertebrate CTLDcp family was essentially formed early in vertebrate evolution and is completely different from the invertebrate families. Comparison of fish and mammalian genomes revealed three groups of CTLDcps and several new members of the known groups, which are highly conserved between fish and mammals, but were not identified in the study using only mammalian genomes. Despite limitations of the draft sequence, the Fugu rubripes genome is a powerful instrument for gene discovery and vertebrate evolutionary analysis. The composition of the CTLDcp superfamily in fish and mammals suggests that large-scale duplication events played an important role in the evolution of vertebrates.
AtSGP1, AtSGP2 and MAP4Kα are nucleolar plant proteins that can complement fission yeast mutants lacking a functional SIN pathway
Authors: Champion Antony , Jouannic Stefan , Guillon Stéfanie , Mockaitis Keithanne , Krapp Andrea , Picaud Alain , Simanis Viesturs , Kreis Martin , Henry Yves
Published: August 2004

In the fission yeast Schizosaccharomyces pombe, the onset of septum formation is signalled via the septation initiation network (SIN) involving several protein kinases and a GTPase. Arabidopsis thaliana and Brassica napus proteins homologous to fission yeast spg1p (AtSGP1, AtSGP2), cdc7p (AtMAP3Kϵ1, AtMAP3Kϵ2, BnMAP3Kϵ1) and sid1p (AtMAP4Kα1, AtMAP4Kα2, BnMAP4Kα2) exhibit a significant similarity. The plant proteins AtSGP1/2 and BnMAP4Kα2 are able to complement the S. pombe mutant proteins spg1-B8 and sid1-239, respectively and to induce mutisepta when overexpressed in wild-type yeast. Yeast two-hybrid assays demonstrated interactions both between plant proteins and between plant and yeast proteins of the SIN pathway. However, the primary structure of the proteins as well as the partial complementation of yeast mutants indicates that plant homologous proteins and their yeast counterparts have diverged during evolution. Real-time RT-PCR studies demonstrated plant SIN-related gene expression in all organs tested and a co-expression pattern during the cell cycle, with a higher accumulation at G2-M. During interphase, the plant SIN-related proteins were found to co-localise predominantly in the nucleolus of the plant cells, as shown by fusions to green fluorescent protein. These data suggest the existence of a plant SIN-related pathway.
Sorting nexin 16 regulates EGF receptor trafficking by phosphatidylinositol-3-phosphate interaction with the Phox domain
Authors: Choi Jang Hyun , Hong Won-Pyo , Kim Myong Jong , Kim Jae Ho , Ryu Sung Ho , Suh Pann-Ghill
Published: August 2004

Sorting nexins (SNXs) containing the Phox (PX) domain are implicated in the regulation of membrane trafficking and sorting processes of epithelial growth factor receptor (EGFR). In this study, we investigated whether SNX16 regulates EGF-induced cell signaling by regulating EGFR trafficking. SNX16 is localized in early and recycling endosomes via its PX domain. Mutation of the PX domain disrupted the association between SNX16 and phosphatidylinositol 3-phosphate [PtdIns(3)P]. Treatment with wortmannin, a PtdIns 3-kinase inhibitor, abolished the endosomal localization of SNX16, suggesting that the intracellular localization of SNX16 is regulated by PtdIns 3-kinase activity. SNX16 was found to associate with EGFR after stimulation with EGF in COS-7 cells. Moreover, overexpression of SNX16 increased the rate of EGF-induced EGFR degradation and inhibited the EGF-induced up-regulation of ERK and serum response element (SRE). In addition, mutation in the PX domain significantly blocked the inhibitory effect of SNX16 on EGF-induced activation of ERK and SRE. From these results, we suggest that SNX16 directs the sorting of EGFR to the endosomal compartment and thus regulates EGF-induced cell signaling.
Treating Functional Impairment of Autism with Selective Serotonin-Reuptake Inhibitors
Authors: Moore Malia L , Eichner Samantha F , Jones Jennifer R
Published: August 2004

OBJECTIVE:

To review literature describing use of selective serotonin-reuptake inhibitors (SSRIs) in the management of functional impairments associated with autistic disorder.

DATA SOURCES:

EMBASE (1980—3rd quarter of 2003), International Pharmaceutical Abstracts (1970–August 2003), and MEDLINE (1966–August 2003) were searched. Search terms included autism, autistic disorder, citalopram, fluoxetine, fluvoxamine, paroxetine, selective serotonin-reuptake inhibitors, and sertraline.

DATA SYNTHESIS:

Studies and case reports evaluating treatment outcomes associated with the use of SSRIs in managing impairments of autism were reviewed. Multiple SSRI dosing ranges were evaluated in autistic patients of different ages with various functional impairments. No specific SSRI or dose range has been shown to improve a specific autistic symptom although some patients have demonstrated improvements.

CONCLUSIONS:

Benefits with SSRIs in treating functional impairments in autism have been observed. Response to therapy and adverse effects are individualized. Current evidence does not support selection of one SSRI over another for any impairment associated with autism.
Highly Sensitive Screening Method for Nitroaromatic, Nitramine and Nitrate Ester Explosives by High Performance Liquid Chromatography—Atmospheric Pressure Ionization—Mass Spectrometry (HPLC-API-MS) in Forensic Applications
Authors: Xu X , van de Craats AM , de Bruyn PCAM
Published: August 2004

A highly sensitive screening method based on high performance liquid chromatography atmospheric pressure ionization mass spectrometry (HPLC-API-MS) has been developed for the analysis of 21 nitroaromatic, nitramine and nitrate ester explosives, which include the explosives most commonly encountered in forensic science. Two atmospheric pressure ionization (API) methods, atmospheric pressure chemical ionization (APCI) and electrospray ionization (ESI), and various experimental conditions have been applied to allow for the detection of all 21 explosive compounds. The limit of detection (LOD) in the full-scan mode has been found to be 0.012–1.2 ng on column for the screening of most explosives investigated. For nitrobenzene, an LOD of 10 ng was found with the APCI method in the negative mode. Although the detection of nitrobenzene, 2-, 3-, and 4-nitrotoluene is hindered by the difficult ionization of these compounds, we have found that by forming an adduct with glycine, LOD values in the range of 3–16 ng on column can be achieved. Compared with previous screening methods with thermospray ionization, the API method has distinct advantages, including simplicity and stability of the method applied, an extended screening range and a low detection limit for the explosives studied.
Characterization of Allegedly Musk-Containing Medicinal Products in Taiwan
Authors: Lin DL , Chang HC , Huang SH
Published: August 2004

As a highly valued ingredient of Chinese medicinal remedies, musk is used as a detoxification agent and for treating fever, inflammation and swelling, and pain. Muscone (3-methylcyclopentadecanone-1), an odoriferous secretion from the ventral glands of male musk deer, is believed to be the active ingredient. A small amount of muscopyridine is also found in the secretion from the ventral glands of male musk deer. Common counterfeit ingredients are musk xylene, musk ambrette, musk ketone, and diphenhydramine. An extraction/GC-MS protocol/data evaluation scheme was developed and applied to study allegedly musk-containing Musk-Tiger Bone Plaster preparations and musk pods (or grains) from Chinese medicine stores and an airport customs. The content of muscone in a specific sample was estimated based on the percentage of the amount recovered from the first extraction. No muscone or counterfeit ingredients were found in all musk pod (or grain) samples from the customs and in the majority of Musk-Tiger Bone Plaster preparations, while muscone (alone or with counterfeit ingredients) was found in most of the musk pod (or grain) collected from Chinese medicine stores.
Addressing the Use of Phylogenetics for Identification of Sequences in Error in the SWGDAM Mitochondrial DNA Database
Authors: Budowle B , Polanskey D , Allard MW , Chakraborty R
Published: August 2004

The SWGDAM mtDNA database is a publicly available reference source that is used for estimating the rarity of an evidence mtDNA profile. Because of the current processes for generating population data, it is unlikely that population databases are error free. The majority of the errors are due to human error and are transcriptional in nature. Phylogenetic analysis of data sets can identify some potential errors, and coupled with a review of the sequence data or alignment sheets can be a very useful tool. Seven sequences with errors have been identified by phylogenetic analysis. In addition, two samples were inadvertently modified when placed in the SWGDAM database. The corrected sequences are provided so that users can modify appropriately the current iteration of the SWGDAM database. From a practical perspective, upper bound estimates of the percentage of matching profiles obtained from a database search containing an incorrect sequence and those of a database containing the corrected sequence are not substantially different. Community wide access and review has enabled identification of errors in the SWGDAM data set and will continue to do so. The result of public accessibility is that the quality of the SWGDAM forensic dataset is always improving.
Persistent Increase in Olfactory Type G-Protein α Subunit Levels May Underlie D1Receptor Functional Hypersensitivity in Parkinson Disease
Authors: Corvol Jean-Christophe , Muriel Marie-Paule , Valjent Emmanuel , Féger Jean , Hanoun Naïma , Girault Jean-Antoine , Hirsch Etienne C. , Hervé Denis
Published: August 2004

Althoughl-dopa remains the most effective treatment of Parkinson disease, its long-term administration is hampered by the appearance of dyskinesia. Hypersensitivity of dopamine D1receptors in the striatum has been suggested to contribute to the genesis of these delayed adverse effects. However, D1receptor amounts are unchanged in Parkinson disease, suggesting alterations of downstream effectors. In rodents, striatal D1receptors activate adenylyl cyclase through olfactory type G-protein α subunit (Gαolf) and G-protein γ 7 subunit (Gγ7). We found that Gαolf was enriched in human basal ganglia and was markedly diminished in the putamen of patients with Huntington disease, in relation with the degeneration of medium spiny neurons. In contrast, in the putamen of patients with Parkinson disease, Gαolf and Gγ7 levels were both significantly increased. In the rat, the degeneration of dopamine neurons augmented Gαolf levels in the striatal neurons, specifically at the plasma membrane, an effect accounting for the increase of D1response on cAMP production in dopamine-depleted striatum. In lesioned rats, Gαolf levels were normalized by a 3 week treatment withl-dopa or a D1agonist but not with aD2-D3agonist, supporting a Gαolf regulation by D1receptor usage. In contrast, the increases of Gαolf levels in patients were not affected by the duration ofl-dopa treatment but correlated with duration of disease. In conclusion, our results revealed in the parkinsonian putamen a prolonged elevation of Gαolf levels that may lead to a persistent D1receptor hypersensitivity and contribute to the genesis of long-term complications ofl-dopa.
Identification of Ectodomain Regions Contributing to Gating, Deactivation, and Resensitization of Purinergic P2X Receptors
Authors: Zemkova Hana , He Mu-Lan , Koshimizu Taka-aki , Stojilkovic Stanko S.
Published: August 2004

The P2X receptors (P2XRs) are a family of ligand-gated channels activated by extracellular ATP through a sequence of conformational transitions between closed, open, and desensitized states. In this study, we examined the dependence of the activity of P2XRs on ectodomain structure and agonist potency. Experiments were done in human embryonic kidney 293 cells expressing rat P2X2aR, P2X2bR, and P2X3R, and chimeras having the V60-R180 or V60-F301 ectodomain sequences of P2X3R instead of the I66-H192 or I66-Y310 sequences of P2X2aR and P2X2bR. Chimeric P2X2a/V60-F301X3R and P2X2b/V60-F301X3R inherited the P2X3R ligand-selective profile, whereas the potency of agonists for P2X2a/V60-R180X3R was in between those observed at parental receptors. Furthermore, P2X2a/V60-F301X3R and P2X2a/V60-R180X3R desensitized in a P2X2aR-specific manner, and P2X2b/V60-F301X3R desensitized with rates comparable with those of P2X2bR. In striking contrast to parental receptors, the rates of decay in P2X2a/V60-F301X3R and P2X2b/V60-F301X3R currents after agonist withdrawal were 15- to 200-fold slower. For these chimeras, the decays in currents were not dependent on duration of stimuli and reflected both continuous desensitization and deactivation of receptors. Also, participation of deactivation in closure of channels inversely correlated with potency of agonists to activate receptors. The delay in deactivation was practically abolished in P2X2a/V60-R180X3R-expressing cells. However, the recovery from desensitization of P2X2a/V60-F301X3R and P2X2a/V60-R180X3R was similar and substantially delayed compared with that of parental receptors. These results indicate that both ectodomain halves participate in gating, but that the C and N halves influence the stability of open and desensitized conformation states, respectively, which in turn reflects on rates of receptor deactivation and resensitization.
Synaptic Strengthening Mediated by Bone Morphogenetic Protein-Dependent Retrograde Signaling in theDrosophilaCNS
Authors: Baines Richard A.
Published: August 2004

Retrograde signaling is an essential component of synaptic development and physiology. Previous studies show that bone morphogenetic protein (BMP)-dependent retrograde signaling is required for the proper development of the neuromuscular junction (NMJ) inDrosophila. These studies, moreover, raised the significant possibility that the development of central motor circuitry might similarly be reliant on such signaling. To test this hypothesis, retrograde signaling between postsynaptic motoneurons and their presynaptic interneurons is examined. Postsynaptic expression of an adenylate cyclase encoded byrutabaga(rut), is sufficient to strengthen synaptic transmission at these identified central synapses. Results are presented to show that the underlying mechanism is dependent on BMP retrograde signaling. Thus, presynaptic expression of an activated TGF-β receptor, thickvien (tkv), or postsynaptic expression of a TGF-β ligand,glass-bottom boat(gbb), is sufficient to phenocopy strengthening of synaptic transmission. In the absence ofgbb, endogenous synaptic transmission is significantly weakened and, moreover, postsynaptic overexpression ofrutis unable to potentiate synaptic function. Potentiation of presynaptic neurotransmitter release, mediated by increased postsynaptic expression ofgbb, is dependent on normal cholinergic activity, indicative that either the secretion of this retrograde signal, or its transduction, is activity dependent. Thus, in addition to the development of the NMJ and expression of myoactive FMRFamide-like peptides in specific central neurons, the results of the present study indicate that this retrograde signaling cascade also integrates the development and function of central motor circuitry that controls movement inDrosophilalarvae.
Setting Boundaries: Brain Dynamics of Modal and Amodal Illusory Shape Completion in Humans
Authors: Murray Micah M. , Foxe Deirdre M. , Javitt Daniel C. , Foxe John J.
Published: August 2004

Normal visual perception requires differentiating foreground from background objects. Differences in physical attributes sometimes determine this relationship. Often such differences must instead be inferred, as when two objects or their parts have the same luminance. Modal completion refers to such perceptual “filling-in” of object borders that are accompanied by concurrent brightness enhancement, in turn termed illusory contours (ICs). Amodal completion is filling-in without concurrent brightness enhancement. Presently there are controversies regarding whether both completion processes use a common neural mechanism and whether perceptual filling-in is a bottom-up, feedforward process initiating at the lowest levels of the cortical visual pathway or commences at higher-tier regions. We previously examined modal completion (Murray et al., 2002) and provided evidence that the earliest modal IC sensitivity occurs within higher-tier object recognition areas of the lateral occipital complex (LOC). We further proposed that previous observations of IC sensitivity in lower-tier regions likely reflect feedback modulation from the LOC. The present study tested these proposals, examining the commonality between modal and amodal completion mechanisms with high-density electrical mapping, spatiotemporal topographic analyses, and the local autoregressive average distributed linear inverse source estimation. A common initial mechanism for both types of completion processes (140 msec) that manifested as a modulation in response strength within higher-tier visual areas, including the LOC and parietal structures, is demonstrated, whereas differential mechanisms were evident only at a subsequent time period (240 msec), with amodal completion relying on continued strong responses in these structures.
Protein Kinase C δ Mediates Cerebral Reperfusion InjuryIn Vivo
Authors: Bright Rachel , Raval Ami P. , Dembner Jeffrey M. , Pérez-Pinzón Miguel A. , Steinberg Gary K. , Yenari Midori A. , Mochly-Rosen Daria
Published: August 2004

Protein kinase C (PKC) has been implicated in mediating ischemic and reperfusion damage in multiple organs. However, conflicting reports exist on the role of individual PKC isozymes in cerebral ischemic injury. Using a peptide inhibitor selective for δPKC, δV1-1, we found that δPKC inhibition reduced cellular injury in a rat hippocampal slice model of cerebral ischemia [oxygen-glucose deprivation (OGD)] when present both during OGD and for the first 3 hr of reperfusion. We next demonstrated peptide delivery to the brain parenchyma afterin vivodelivery by detecting biotin-conjugatedδV1-1 and by measuring inhibition of intracellular δPKC translocation, an indicator of δPKC activity. Delivery of δV1-1 decreased infarct size in anin vivorat stroke model of transient middle cerebral artery occlusion. Importantly, δV1-1 had no effect when delivered immediately before ischemia. However, delivery at the onset, at 1 hr, or at 6 hr of reperfusion reduced injury by 68, 47, and 58%, respectively. Previous work has implicated δPKC in mediating apoptotic processes. We therefore determined whether δPKC inhibition altered apoptotic cell death or cell survival pathways in our models. We found that δV1-1 reduced numbers of terminal deoxynucleotidyl transferase-mediated biotinylated UTP nick end labeling-positive cells, indicating decreased apoptosis, increased levels of phospho-Akt, a kinase involved in cell survival pathways, and inhibited BAD (Bcl-2-associated death protein) protein translocation from the cell cytosol to the membrane, indicating inhibition of proapoptotic signaling. These data support a deleterious role for δPKC during reperfusion and suggest that δV1-1 delivery, even hours after commencement of reperfusion, may provide a therapeutic advantage after cerebral ischemia.