bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of Nutritional Quality between Chinese Indica Rice with sck and cry1Ac Genes and Its Nontransgenic Counterpart
Authors: Li X. , Huang K. , He X. , Zhu B. , Liang Z. , Li H. , Luo Y.
Published: June 2007

ABSTRACT:  Nutritional assessment of transgenic crops used for human food and animal feed is an important aspect of safety evaluations. An insect‐resistant rice (IRR) was generated by the stable insertion of sck, a modified cowpea trypsin inhibitor gene, and cry1Ac, encoding a crystal protein from Bacillus thuringiensis into the genome of a common variety of Chinese indica rice. The composition of the brown and milled rice grain from the resulted IRR line designated Liangyou Kefeng No. 6 was compared with that of the parental rice cultivar Liangyou 2186. Nutrients, including the proximates, amino acids, fatty acids, minerals, and vitamins, were measured. The antinutritive components such as phytic acid, lectin, and trypsin inhibitors were also examined. The data demonstrated that the nutritional quality of both the brown and milled rice grains from the transgenic line was substantially equivalent to that of the nontransgenic counterpart, and measured amounts of nutritional components fell within the range of values reported for other commercial lines.
Calibration and Validation of ADAPT and SWAT for Field‐Scale Runoff Prediction1
Authors: Anand Shilpa , Mankin Kyle R. , McVay Kent A. , Janssen Keith A. , Barnes Philip L. , Pierzynski Gary M.
Published: June 2007

Abstract:  The pollutant reduction possible with a given agricultural best‐management practice (BMP) is complex and site‐specific. Water‐quality models can evaluate BMPs, but model results are often limited by the lack of calibrated parameters for a given BMP. This study calibrated runoff prediction of two models (ADAPT and SWAT) for individual field plots having one till and two no‐till management practices. The factors used for runoff calibration were curve number II (CNII) and saturated hydraulic conductivity (Ksat) for ADAPT, and CNII, Ksat, and available water capacity for SWAT. Results were evaluated using coefficient of determination (R2), Nash‐Sutcliffe efficiency (Ef), root‐mean square error, median‐based Ef, and sign tests. Results indicated that for ADAPT, the best‐fit CNII was 66 for the NT/SB (no‐till plot with surface‐broadcast fertilizer) treatment, 68 for the NT/DB (no‐till with deep‐banded fertilizer) treatment, and 70 for the tilled plot, whereas for SWAT the best‐fit CNII was much higher, 86, for all treatments. Neither agreed with the textbook CNII, 78, for sorghum in silty clay loam soil. The best‐fit model parameters for both runoff calibration phases had excellent correlation to monthly totals and moderate correlation to individual events.
Pesticide and Transformation Product Detections and Age‐Dating Relations from Till and Sand Deposits1
Authors: Warner Kelly L. , Morrow William S.
Published: June 2007

Abstract:  Pesticide and transformation product concentrations and frequencies in ground water from areas of similar crop and pesticide applications may vary substantially with differing lithologies. Pesticide analysis data for atrazine, metolachlor, alachlor, acetochlor, and cyanazine and their pesticide transformation products were collected at 69 monitoring wells in Illinois and northern Indiana to document occurrence of pesticides and their transformation products in two agricultural areas of differing lithologies, till, and sand. The till is primarily tile drained and has preferential fractured flow, whereas the sand primarily has surface water drainage and primary porosity flow. Transformation products represent most of the agricultural pesticides in ground water regardless of aquifer material – till or sand. Transformation products were detected more frequently than parent pesticides in both the till and sand, with metolachlor ethane sulfonic acid being most frequently detected. Estimated ground‐water recharge dates for the sand were based on chlorofluorocarbon analyses. These age‐dating data indicate that ground water recharged prior to 1990 is more likely to have a detection of a pesticide or pesticide transformation product. Detections were twice as frequent in ground water recharged prior to 1990 (82%) than in ground water recharged on or after 1990 (33%). The highest concentrations of atrazine, alachlor, metolachlor, and their transformation products, also were detected in samples from ground water recharged prior to 1990. These age/pesticide detection relations are opposite of what would normally be expected, and may be the result of preferential flow and/or ground‐water mixing between aquifers and aquitards as evident by the detection of acetochlor transformation products in samples with estimated ground‐water ages predating initial pesticide application.
Mercury Accumulation in Periphyton of Eight River Ecosystems1
Authors: Bell Amanda H. , Scudder Barbara C.
Published: June 2007

Abstract:  In 2003, the U.S. Geological Survey (USGS) National Water‐Quality Assessment (NAWQA) program and U.S. Environmental Protection Agency studied total mercury (THg) and methylmercury (MeHg) concentrations in periphyton at eight rivers in the United States in coordination with a larger USGS study on mercury cycling in rivers. Periphyton samples were collected using trace element clean techniques and NAWQA sampling protocols in spring and fall from targeted habitats (streambed surface‐sediment, cobble, or woody snags) at each river site. A positive correlation was observed between concentrations of THg and MeHg in periphyton (r2 = 0.88, in log‐log space). Mean MeHg and THg concentrations in surface‐sediment periphyton were significantly higher (1,333 ng/m2 for MeHg and 53,980 ng/m2 for THg) than cobble (64 ng/m2 for MeHg and 1,192 ng/m2 for THg) or woody snag (71 ng/m2 for MeHg and 1,089 ng/m2 for THg) periphyton. Concentrations of THg in surface‐sediment periphyton had a strong positive correlation with concentrations of THg in sediment (dry weight). The ratio of MeHg:THg in surface‐sediment periphyton increased with the ratio of MeHg:THg in sediment. These data suggest periphyton may play a key role in mercury bioaccumulation in river ecosystems.
Type IVB Pilus Operon Promoter Controlling Expression of the Severe Acute Respiratory Syndrome-Associated Coronavirus Nucleocapsid Gene in
Salmonella enterica
Serovar Typhi Elicits Full Immune Response by Intranasal Vaccination
Authors: Luo Fengling , Feng Yong , Liu Min , Li Pingfei , Pan Qin , Jeza Victor Tunje , Xia Bing , Wu Jianguo , Zhang Xiao-Lian
Published: June 2007

Attenuated
Salmonella enterica
serovar Typhi strains have been considered to be attractive as potential live oral delivery vector vaccines because of their ability to elicit the full array of immune responses in humans. In this study, we constructed an attenuated
S. enterica
serovar Typhi strain stably expressing conserved nucleocapsid (N) protein of severe acute respiratory syndrome-associated coronavirus (SARS-CoV) by integrating the N gene into the
pilV
gene, which was under the control of the type IVB pilus operon promoter in
S. enterica
serovar Typhi. BALB/c mice were immunized with this recombinant strain through different routes: intranasally, orogastrically, intraperitoneally, and intravenously. Results showed that the intranasal route caused the highest production of specific immunoglobulin G (IgG), IgG2a, and secretory IgA, where IgG2a was imprinted as a Th1 cell bias. Moreover, this recombinant live vaccine induced significantly high levels of specific cytotoxic T-lymphocyte activities and increased gamma interferon-producing T cells compared with the parental strain. Our work provides insights into how the type IVB pilus operon promoter controlling SARS-CoV N gene expression in
Salmonella
might be attractive for a live-vector vaccine against SRAS-CoV infection, for it could induce mucosal, humoral, and cellular immune responses. Our work also indicates that the type IVB pilus operon promoter controlling foreign gene expression in
Salmonella
can elicit full immune responses by intranasal vaccination.
First Pulmonary Case Reported in Argentina of Infection with
Mycobacterium szulgai
, a Rare Pathogen
Authors: Gutierrez M. , Feola M. , Lenge L. , Rey R. , Hoffman M.
Published: June 2007

Mycobacterium szulgai
is a rare pathogen. Nontuberculous mycobacteria usually produce disease in people with some kind of immunosuppression or another predisposing condition. A case of pulmonary
Mycobacterium szulgai
infection is described.
Comparison of the Abbott 7000 and Bayer 340 Systems for Measurement of Hepatitis C Virus Load
Authors: Highbarger Helene C. , Hu Zonghui , Kottilil Shyam , Metcalf Julia A. , Polis Michael A. , Vasudevachari M. B. , Lane H. Clifford , Dewar Robin L.
Published: June 2007

This study compared two commercially available assays for the measurement of hepatitis C virus (HCV) RNA levels, the Bayer HCV RNA (version 3.0) branched DNA assay and the Abbott HCV analyte-specific reagent real-time PCR assay, to assess their quantitative relationships, ease of performance, and time to completion. The study group consisted of randomly selected patients from the NIAID human immunodeficiency virus (HIV) outpatient clinic who were infected with HIV type 1 and HCV. One hundred eighty-four samples from 66 patients coinfected with HIV and HCV receiving treatments under various protocols were analyzed for the correlation and agreement of the results. The results indicated that the two assays correlate well in the overlapping linear ranges of the assays and show good agreement. From the results obtained, we have derived a mathematical formula to compare the viral load results between the two assays, which is given as log
10
Abbott assay measure = 0.032 + 1.01 log
10
Bayer assay measure. Although it is preferable to use the same quantitation assay throughout the course of a patient's treatment, valid comparisons of the HCV RNA levels may be made between the results obtained by either of these assays in the overlapping linear range (615 to 7,700,000 IU/ml).
Multicenter Study To Evaluate Bloodstream Infection by
Helicobacter cinaedi
in Japan
Authors: Matsumoto Tetsuya , Goto Mieko , Murakami Hinako , Tanaka Takashi , Nishiyama Hiroyuki , Ono Emi , Okada Chikako , Sawabe Etsuko , Yagoshi Michiko , Yoneyama Akiko , Okuzumi Katsuko , Tateda Kazuhiro , Misawa Naoaki , Yamaguchi Keizo
Published: June 2007

Helicobacter cinaedi
has being recognized as an important human pathogen which causes bloodstream infections. Although the first case of bacteremia with this pathogen in Japan was reported in 2003, the true prevalence of
H. cinaedi
as a pathogen of bloodstream infections in this country is not yet known. Therefore, the aim of our study was to assess the incidence of bacteremia with
H. cinaedi
in Japan. We conducted a prospective, multicenter analysis in 13 hospitals during 6 months in Tokyo, Japan. Among positive blood cultures from 1 October 2003 to 31 March 2004, isolates suspected of being
Helicobacter
species were studied for further microbial identification. Identification of the organisms was based on their biochemical traits and the results of molecular analysis of their 16S rRNA gene sequences. A total of 16,743 blood culture samples were obtained during the study period, and 2,718 samples (17.7%) yielded positive culture results for coagulase-negative staphylococci. Among nine isolates suspected to be
Helicobacter
species, six isolates were finally identified as
H. cinaedi
. The positivity rate for
H. cinaedi
in blood culture was 0.06% of total blood samples and 0.22% of blood samples with any positive culture results. All patients with bacteremia with
H. cinaedi
were found to have no human immunodeficiency virus (HIV) infection, but many of them had complications with either malignancy, renal failure, or a history of surgical operation. Therefore, our results suggest that bacteremia with
H. cinaedi
is rare but can occur in compromised hosts other than those with HIV infection in Japan.
MultiCode-PLx System for Multiplexed Detection of Seventeen Respiratory Viruses
Authors: Nolte Frederick S. , Marshall David J. , Rasberry Christopher , Schievelbein Sabina , Banks Grier G. , Storch Gregory A. , Arens Max Q. , Buller Richard S. , Prudent James R.
Published: June 2007

The MultiCode-PLx system (EraGen Biosciences, Inc., Madison, WI) for the detection of respiratory viruses uses an expanded genetic alphabet, multiplex PCR chemistry, and microsphere flow cytometry to rapidly detect and specifically identify 17 different respiratory viruses directly in clinical specimens. The MultiCode-PLx system was tested in parallel with direct fluorescent-antibody (DFA) staining and rapid shell vial culture (R-mix cells; Diagnostic Hybrids, Inc. Athens, OH) with 354 respiratory specimens from adult patients that were submitted to the clinical virology laboratory at the Emory University Hospital. Single-target PCRs were performed with retained samples to confirm the positive results obtained with the MultiCode-PLx system for viruses not covered by DFA and R-mix culture (metapneumovirus, coronaviruses [CoV], parainfluenza viruses 4a and 4b, and rhinoviruses) and to resolve any discrepancies between the DFA and R-mix culture and the MultiCode-PLx results for viruses common to both systems. Respiratory viruses were detected in 77 (21.8%) and 116 (32.7%) specimens by DFA and R-mix culture and with the MultiCode-PLx system, respectively. Among the viruses common to both systems, the MultiCode-PLx system detected significantly more influenza A viruses (
P
= 0.0026). An additional increased diagnostic yield with the MultiCode-PLx system resulted from the detection of human metapneumovirus (HMPV) in 9 specimens, human CoV (HCoV) in 3 specimens, and human rhinovirus (HRV) in 16 specimens. Also, two mixed viral infections were detected by the MultiCode-PLx system (HCoV OC43 and HRV infections and HMPV and HRV infections), but none were detected by DFA and R-mix culture. Single-target PCRs verified the results obtained with the MultiCode-PLx system for 73 of 81 (90.1%) specimens that had discordant results or that were not covered by DFA and R-mix culture. The MultiCode-PLx system provides clinical laboratories with a practical, rapid, and sensitive means for the massively multiplexed molecular detection of common respiratory viruses.
Convenient Test Using a Combination of Chelating Agents for Detection of Metallo-β-Lactamases in the Clinical Laboratory
Authors: Kim Soo-Young , Hong Seong Geun , Moland Ellen S. , Thomson Kenneth S.
Published: June 2007

Although transmissible metallo-β-lactamases (MBLs) are a serious threat to β-lactam antibiotic therapy, the CLSI currently does not recommend testing methods for the detection of MBLs. The aim of this study was to evaluate the capability of double-disk tests (DDTs) by using disks containing a combination of the chelators 2-mercaptopropionic acid (MPA) and Tris-EDTA (TE) to detect MBLs. Sixteen isolates (4
Acinetobacter baumannii
isolates, 6
Pseudomonas aeruginosa
isolates, 1
Serratia marcescens
isolate, 1
Aeromonas hydrophila
isolate, 1
Aeromonas veronii
isolate, 2
Chryseobacterium meningosepticum
isolates, and 1
Stenotrophomonas maltophilia
isolate) producing IMP-1, IMP-1-like, IMP-18, GIM-1, SPM-1, VIM-2, VIM-2-like, and chromosomal MBLs and 20 isolates (7
Klebsiella pneumoniae
isolates, 3
Escherichia coli
isolates, 5
Enterobacter cloacae
isolates, 2
S. marcescens
isolates, 1
Proteus mirabilis
isolate, and 2
A. baumannii
isolates) producing non-MBL carbapenemases, AmpC β-lactamases, and extended-spectrum β-lactamases were tested. The DDT method was evaluated by using four types of chelator disks (TE, high-strength TE, MPA, and TE plus 20 μl of MPA [at various concentrations]) and the β-lactams imipenem (IPM), meropenem (MEM), ertapenem (ERT), and ceftazidime (CAZ). DDTs with IPM and a TE disk supplemented with 1:320 MPA detected all MBLs and yielded no false-positive results. Some, but not all, MBL producers were detected in IPM-based tests involving the single chelator TE or MPA alone or by ERT- or CAZ-based tests. IPM-based tests with MPA concentrations other than 1:320 and all MEM-based tests had suboptimal sensitivities or specificities. DDT with IPM and a TE disk supplemented with 20 μl of 1:320 MPA appears to be convenient for the detection of MBLs in the clinical laboratory.
Respiratory Syncytial Virus Infects and Abortively Replicates in the Lungs in Spite of Preexisting Immunity
Authors: Boukhvalova Marina S. , Prince Gregory A. , Blanco Jorge C. G.
Published: June 2007

Respiratory syncytial virus (RSV) is a major cause of bronchiolitis and viral pneumonia in young children and a serious health risk in immunocompromised individuals and the elderly. Immunity to RSV is not completely understood. In this work, we established a method for monitoring RSV infection by real-time PCR and applied this method for analysis of RSV replication in vivo in the cotton rat model in naïve animals and in animals rendered immune to RSV by prior RSV infection. We found that even though no virus could be isolated from the lungs of RSV-challenged immune animals, RSV infection in fact took place and an accumulation of viral RNA transcripts was observed. This type of replication, therefore, can be termed “abortive,” as RSV is capable of entering the cells in the lungs of immune animals, yet the production of progeny viruses is impaired. Similar patterns of RSV gene expression gradient were observed between naïve and reinfected animals, indicating that the skewing of mRNA gradient of viral gene expression, a mechanism documented during latent infection by other viruses, is not likely to be responsible for abortive replication of RSV during reinfection. We found that passive administration of antibodies to RSV prevents productive infection normally accompanied by viral release in the lung, but it does not prevent abortive replication of the virus. To the best of our knowledge, this is the first evidence of abortive replication of RSV in vivo.
Bovine Papillomavirus E7 Oncoprotein Inhibits Anoikis
Authors: DeMasi Joseph , Chao Michael C. , Kumar Ashu S. , Howley Peter M.
Published: June 2007

The bovine papillomavirus type 1 (BPV-1) E7 oncoprotein is required for the full transformation activity of the virus. Although BPV-1 E7 by itself is not sufficient to induce cellular transformation, it enhances the abilities of the other BPV-1 oncogenes to induce anchorage independence. We have been exploring the mechanisms by which E7 might affect the transformation efficiency of other viral oncoproteins and in particular whether it might protect cells from apoptosis. We report here that BPV-1 E6 and E7 can each independently inhibit anoikis, a type of apoptosis that is induced upon cell detachment. Using site-directed mutagenesis, we determined regions of the E7 protein that were essential for its antiapoptotic activity. The ability of E7 to inhibit anoikis did partially correlate with an ability to enhance anchorage independence of BPV-1 E6-transformed cells. In addition, the antiapoptotic activity of E7 also only partially correlated with its ability to bind p600, a cellular protein that has previously been reported to play a role in anoikis. We conclude that the contribution of E7 to BPV-induced cellular transformation may involve its ability to inhibit anoikis but that additional functional activities must also be involved.
Human Cytomegalovirus Gene Expression Is Silenced by Daxx-Mediated Intrinsic Immune Defense in Model Latent Infections Established In Vitro
Authors: Saffert Ryan T. , Kalejta Robert F.
Published: June 2007

In addition to productive lytic infections, herpesviruses such as human cytomegalovirus (HCMV) establish a reservoir of latently infected cells that permit lifelong colonization of the host. When latency is established, the viral immediate-early (IE) genes that initiate the lytic replication cycle are not expressed. HCMV IE gene expression at the start of a lytic infection is facilitated by the viral pp71 protein, which is delivered to cells by infectious viral particles. pp71 neutralizes the Daxx-mediated cellular intrinsic immune defense that silences IE gene expression by generating a repressive chromatin structure on the viral major IE promoter (MIEP). In naturally latently infected cells and in cells latently infected in vitro, the MIEP also adopts a similar silenced chromatin structure. Here we analyze the role of Daxx in quiescent HCMV infections in vitro that mimic some, but not all, of the characteristics of natural latency. We show that in these “latent-like” infections, the Daxx-mediated defense that represses viral gene expression is not disabled because pp71 and Daxx localize to different cellular compartments. We demonstrate that Daxx is required to establish quiescent HCMV infections in vitro because in cells that would normally foster the establishment of these latent-like infections, the loss of Daxx causes the lytic replication cycle to be initiated. Importantly, the lytic cycle is inefficiently completed, which results in an abortive infection. Our work demonstrates that, in certain cell types, HCMV must silence its own gene expression to establish quiescence and prevent abortive infection and that the virus usurps a Daxx-mediated cellular intrinsic immune defense mechanism to do so. This identifies Daxx as one of the likely multiple viral and cellular determinants in the pathway of HCMV quiescence in vitro, and perhaps in natural latent infections as well.
De Novo Protein Synthesis Is Required for Lytic Cycle Reactivation of Epstein-Barr Virus, but Not Kaposi's Sarcoma-Associated Herpesvirus, in Response to Histone Deacetylase Inhibitors and Protein Kinase C Agonists
Authors: Ye Jianjiang , Gradoville Lyndle , Daigle Derek , Miller George
Published: June 2007

The oncogenic human gammaherpesviruses, Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV), are latent in cultured lymphoma cells. We asked whether reactivation from latency of either virus requires de novo protein synthesis. Using Northern blotting and quantitative reverse transcriptase PCR, we measured the kinetics of expression of the lytic cycle activator genes and determined whether abundance of mRNAs encoding these genes from either virus was reduced by treatment with cycloheximide (CHX), an inhibitor of protein synthesis. CHX blocked expression of mRNAs of EBV BZLF1 and BRLF1, the two EBV lytic cycle activator genes, when HH514-16 Burkitt lymphoma cells were treated with histone deacetylase (HDAC) inhibitors, sodium butyrate or trichostatin A, or a DNA methyltransferase inhibitor, 5-Aza-2′-deoxycytidine. CHX also inhibited EBV lytic cycle activation in B95-8 marmoset lymphoblastoid cells by phorbol ester phorbol-12-myristate-13-acetate (TPA). EBV lytic cycle induction became resistant to CHX between 4 and 6 h after application of the inducing stimulus. KSHV lytic cycle activation, as assessed by ORF50 mRNA expression, was rapidly induced by the HDAC inhibitors, sodium butyrate and trichostatin A, in HH-B2 primary effusion lymphoma cells. In HH-B2 cells, CHX did not inhibit, but enhanced, expression of the KSHV lytic cycle activator gene, ORF50. In BC-1, a primary effusion lymphoma cell line that is dually infected with EBV and KSHV, CHX blocked EBV BRLF1 lytic gene expression induced by TPA and sodium butyrate; KSHV ORF50 mRNA induced simultaneously in the same cells by the same inducing stimuli was resistant to CHX. The experiments show, for the cell lines and inducing agents studied, that the EBV BZLF1 and BRLF1 genes do not behave with “immediate-early” kinetics upon reactivation from latency. KSHV ORF50 is a true “immediate-early” gene. Our results indicate that the mechanism by which HDAC inhibitors and TPA induce lytic cycle gene expression of the two viruses differs and suggest that EBV but not KSHV requires one or more proteins to be newly synthesized between 4 and 6 h after application of an inducing stimulus.
Secretory Mechanisms in Cell-Mediated Cytotoxicity
Authors: Stinchcombe Jane C. , Griffiths Gillian M.
Published: June 2007

Cytotoxic T lymphocytes (CTLs) play a critical role in the immune system; they are able to recognize and destroy virally infected and tumorigenic cells. Specific recognition of MHC class I–peptide complexes by the T cell receptor (TcR) results in precise delivery of lytic granules to the target cell, sparing neighboring cells and the CTL itself. Over the past 10 years various studies have eludicated the mechanisms that lead to the rapid polarization of the secretory apparatus in CTLs. These studies highlight similarities and differences between polarity and secretory mechanisms seen in other cell types and developmental systems. This review focuses on recent advances in our understanding of the molecular basis of polarized secretion from CTLs and the novel mechanism used by these cells to deliver their lethal hit.
The Origin and Establishment of the Plastid in Algae and Plants
Authors: Reyes-Prieto Adrian , Weber Andreas P.M. , Bhattacharya Debashish
Published: June 2007

The establishment of the photosynthetic organelle (plastid) in eukaryotes and the diversification of algae and plants were landmark evolutionary events because these taxa form the base of the food chain for many ecosystems on our planet. The plastid originated via a putative single, ancient primary endosymbiosis in which a heterotrophic protist engulfed and retained a cyanobacterium in its cytoplasm. Once successfully established, this plastid spread into other protist lineages through eukaryote-eukaryote (secondary and tertiary) endosymbioses. This process of serial cell capture and enslavement explains the diversity of photosynthetic eukaryotes. Recent genomic and phylogenomic approaches have significantly clarified plastid genome evolution, the movement of endosymbiont genes to the “host” nuclear genome (endosymbiotic gene transfer), and plastid spread throughout the eukaryotic tree of life. Here we review these aspects of plastid evolution with a focus on understanding early events in plastid endosymbiosis.
Structural insights into the role of the ACTH receptor cysteine residues on receptor function
Authors: Yang Yingkui , Chen Min , Kesterson Robert Allen , Harmon Carroll M.
Published: June 2007

The ACTH receptor, also known as the melanocortin-2 receptor (MC2R), is critical for ACTH-mediated adrenal glucocorticoid release. Human MC2R (hMC2R) has 10 cysteine residues, which are located in extracellular loops (ELs), transmembrane domains (TMs), and intracellular loops (ILs). In this study, we examined the importance of these cysteine residues in receptor function and determined their involvement in disulfide bond formation. We replaced these cysteines with serine and expressed the mutated receptors in adrenal OS3 cells, which lack endogenous MC2R. Our results indicate that four mutations, C21S in NH2terminus, C245S, C251S, and C253S in EL3, resulted in significant decrease both in receptor expression and receptor function. Mutation of cysteine 231 in TM6 significantly decreased ACTH binding affinity and potency. In contrast, the five other mutated receptors (C64S, C158S, C191S, C267S, and C293S) did not significantly alter ACTH binding affinity and potency. These results suggest that extracellular cysteine residue 21, 245, 251, and 253, as well as transmembrane cysteine residue 231 are crucial for ACTH binding and signaling. Further experiments suggest that a disulfide bond exists between the residue C245 and C251 in EL3. These findings provide important insights into the importance of cysteine residues of hMC2R for receptor function.
Antioxidants attenuate high glucose-induced hypertrophic growth in renal tubular epithelial cells
Authors: Huang Jau-Shyang , Chuang Lea-Yea , Guh Jinn-Yuh , Huang Yann-Jia , Hsu Min-Shyang
Published: June 2007

Hyperglycemia-induced oxidative stress is a key mediator of renal tubular hypertrophy in diabetic nephropathy (DN). The molecular mechanisms of antioxidants responsible for inhibition of renal tubular hypertrophy in DN are incompletely characterized. We now aim at verifying the effects of N-acetylcysteine (NAC) and taurine on cellular hypertrophy in renal tubular epithelial cells under high ambient glucose. We found that NAC and taurine treatments significantly attenuated high glucose (HG)-inhibited cellular growth and HG-induced hypertrophy. HG-induced Raf-1, p42/p44 mitogen-activated protein kinase (MAPK), Janus kinase 2 (JAK2), and signal transducer and activator of transcription 1 (STAT1) and STAT3 (but not STAT5) activation was markedly blocked by NAC and taurine. Moreover, NAC and taurine increased cyclin D1/cdk4 activation and suppressed p21Waf1/Cip1 and p27Kip1 expression in HG-treated cells. It seems that apoptosis was not observed in these treatments. There were no changes in bcl-2 and poly(ADP-ribose) polymerase expression, and mitochondrial cytochrome c release. However, NAC or taurine markedly inhibited the stimulation by HG of fibronectin and type IV collagen protein levels. It is concluded that both NAC and taurine significantly attenuated HG-induced activation of the Raf-1/MAPK and the JAK2-STAT1/STAT3 signaling pathways and hypertrophic growth in renal tubular epithelial cells.
Intracellular trafficking of a polymorphism in the COOH terminus of the α-subunit of the human epithelial sodium channel is modulated by casein kinase 1
Authors: Yan Wusheng , Spruce Lynn , Rosenblatt Michael M. , Kleyman Thomas R. , Rubenstein Ronald C.
Published: June 2007

The A663T polymorphism of the α-subunit of the human epithelial sodium channel (hENaC) increases the functional and surface expression of αβγ-hENaC in Xenopus laevis oocytes, and the context of this residue in the COOH terminus of α-hENaC is important for this effect. Query of a phosphoprotein database suggested that the α-T663 residue of hENaC might be a substrate for phosphorylation by casein kinase 1 (CK1). We tested the hypotheses that phosphorylation of α-T663-hENaC by CK1 would regulate the increased functional and surface expression of α-T663-hENaC vs. α-A663-hENaC in oocytes. General inhibition of CK1 with IC261 decreased the functional and surface expression of α-T663-hENaC, but not α-A663-hENaC. This decrease in α-T663-hENaC functional expression resulted from reduced delivery of α-T663-hENaC to the oocyte membrane. IC261 also inhibited the functional expression of α-T692-mENaC and a chimeric m(1-678)/h(650-669)α-T663, mβγ ENaC, but not α-A692-mENaC or m(1-678)/h(650-669)α-A663, mβγ ENaC. These data suggest that additional residues outside of the α-hENaC COOH terminus are important for modulation of α-T663-hENaC trafficking by CK1. Overexpression of CK1α did not alter functional expression of α-T663-hENaC. In contrast, modest overexpression of CK1δ enhanced, whereas higher levels of CK1δ overexpression inhibited α-T663-hENaC functional expression. CK1 did not phosphorylate the COOH terminus of either α-T663-hENaC or α-A663-hENaC in vitro. These data suggest that CK1, and perhaps specifically CK1δ, regulates the intracellular trafficking of the α-A663T functional polymorphism of hENaC indirectly by altering the rate of α-T663-hENaC biosynthesis and/or delivery to the plasma membrane.
ACE inhibitor reduces growth factor receptor expression and signaling but also albuminuria through B2-kinin glomerular receptor activation in diabetic rats
Authors: Allard Julien , Buléon Marie , Cellier Eric , Renaud Isabelle , Pecher Christiane , Praddaude Françoise , Conti Marc , Tack Ivan , Girolami Jean-Pierre
Published: June 2007

Diabetic nephropathy (DN) is associated with increased oxidative stress, overexpression and activation of growth factor receptors, including those for transforming growth factor-β1 (TGF-β-RII), platelet-derived growth factor (PDGF-R), and insulin-like growth factor (IGF1-R). These pathways are believed to represent pathophysiological determinants of DN. Beyond perfect glycemic control, angiotensin-converting enzyme inhibitors (ACEI) are the most efficient treatment to delay glomerulosclerosis. Since their mechanisms of action remain uncertain, we investigated the effect of ACEI on the glomerular expression of these growth factor pathways in a model of streptozotocin-induced diabetes in rats. The early phase of diabetes was found to be associated with an increase in glomerular expression of IGF1-R, PDGF-R, and TGF-β-RII and activation of IRS1, Erk 1/2, and Smad 2/3. These changes were significantly reduced by ACEI treatment. Furthermore, ACEI stimulated glutathione peroxidase activity, suggesting a protective role against oxidative stress. ACEI decreased ANG II production but also increased bradykinin bioavailability by reducing its degradation. Thus the involvement of the bradykinin pathway was investigated using coadministration of HOE-140, a highly specific nonpeptidic B2-kinin receptor antagonist. Almost all the previously described effects of ACEI were abolished by HOE-140, as was the increase in glutathione peroxidase activity. Moreover, the well-established ability of ACEI to reduce albuminuria was also prevented by HOE-140. Taken together, these data demonstrate that, in the early phase of diabetes, ACEI reverse glomerular overexpression and activation of some critical growth factor pathways and increase protection against oxidative stress and that these effects involve B2-kinin receptor activation.
Quantitative Comparison Between Neural Response in Macaque Inferotemporal Cortex and Behavioral Discrimination of Photographic Images
Authors: Allred Sarah R. , Jagadeesh Bharathi
Published: June 2007

Inferotemporal (IT) cortex plays a critical role in the primate ability to perceive and discriminate between images, but the relationship between responses of single neurons and behavioral capacities is poorly understood. We studied this relationship by recording from IT neurons while monkeys performed a delayed-match-to-sample task with two images. On each day, two sample images were chosen to maximize the selectivity of the neuron and task difficulty was manipulated by varying sample duration and by masking the sample. On each trial, monkeys reported which of the two sample images was presented. Neural performance was described using an ideal-observer analysis. Across the population, neural and behavioral sensitivity to changes in sample duration were indistinguishable. Neural sensitivity was dependent on epoch used to analyze neural response; maximal neural sensitivity was achieved in the 128-ms epoch that began 85 ms after sample onset. At most sample durations, the epoch that yielded optimal neural performance was longer than the sample duration, suggesting that neural selectivity persisted after the presentation of the mask during performance of the task. A control experiment showed that neural and behavioral performance improved in the absence of the mask. These observations suggest that the responses of individual IT neurons contain sufficient information to allow behavioral discrimination of images in a demanding task.
Intersegmental Coordination: Influence of a Single Walking Leg on the Neighboring Segments in the Stick Insect Walking System
Authors: Borgmann Anke , Scharstein Hans , Büschges Ansgar
Published: June 2007

A key element of walking is the coordinated interplay of multiple limbs to achieve a stable locomotor pattern that is adapted to the environment. We investigated intersegmental coordination of walking in the stick insect, Carausius morosus by examining the influence a single stepping leg has on the motoneural activity of the other hemiganglia, and whether this influence changes with the walking direction. We used a reduced single leg walking preparation with only one intact front, middle, or hind leg. The intact leg performed stepping movements on a treadmill, thus providing intersegmental signals about its stepping to the other hemiganglia. The activity of coxal motoneurons was simultaneously recorded extracellularly in all other segments. Stepping sequences of any given single leg in either walking direction were accompanied by an increase in coxal motoneuron (MN) activity of all other segments, which was mostly modulated and slightly in phase with stance of the walking leg. In addition, forward stepping of the front leg and, to a lesser extent, backward stepping of the hind leg elicited alternating activity in mesothoracic coxal MNs. Forward and backward stepping of the middle leg did not elicit alternating activity in coxal MNs in any other hemiganglia, indicating that the influence of middle leg stepping is qualitatively different from that of forward front and backward hind leg stepping. Our results indicate that in an insect walking system individual segments differ with respect to their intersegmental influences and thus cannot be treated as similar within the chain of segmental walking pattern generators. Consequences for the current concepts on intersegmental coordination are discussed.
Synchrony: A Neural Correlate of Somatosensory Attention
Authors: Roy A. , Steinmetz P. N. , Hsiao S. S. , Johnson K. O. , Niebur E.
Published: June 2007

We investigated whether synchrony between neuronal spike trains is affected by the animal's attentional state. Cross-correlation functions between pairs of spike trains in the second somatosensory cortex (SII) of three macaque monkeys trained to switch attention between a visual task and a tactile task were computed. We previously showed that the majority of recorded neuron pairs (66%) in SII cortex fire synchronously while the animals performed either task and that in a subset of neuron pairs (17%), the degree of synchrony was affected by the animal's attentional state. Of the neuron pairs that showed changes in synchrony with attention, about 80% showed increased synchrony when the animal attended to the tactile stimulus. Here, we show that peak correlation typically occurred at a delay <25 ms; most commonly the delay was close to zero. Half-widths of the correlation peaks were distributed between a few milliseconds and hundreds of milliseconds, with the majority lying <100 ms and the mode of the distribution around 20–30 ms. Maximal change in synchrony occurred mainly during the periods when the stimulus was present, and synchrony usually increased when attention was on the tactile stimulus. If periods of elevated firing rates around the motor response times were removed from the analysis, the percentage of pairs that changed the degree of synchrony with attention more than doubled (from 35 to 72%). The observed effects did not depend on details of the statistical criteria or of the time window used in the analysis.
Suppression at High Spatial Frequencies in the Lateral Geniculate Nucleus of the Cat
Authors: Nolt M. J. , Kumbhani R. D. , Palmer L. A.
Published: June 2007

The spatial weighting functions of both retinal and lateral geniculate nucleus (LGN) X-cell receptive fields have been viewed as the difference of two Gaussians (DOG). We focus on a particular shortcoming of the DOG model, that is, suppression of responses of LGN cells at spatial frequencies above those to which the classical receptive field surround is responsive. By simultaneously recording one of the retinal ganglion cell (RGC) inputs (S-potentials) to an LGN cell, we find that half of this suppression at high spatial frequencies arises from the retinal input and that suppression in LGN cells is greater than that in RGCs, regardless of spatial frequency. We also inactivated the ipsilateral visual cortex and show that one quarter of the suppression at high spatial frequencies arises from corticothalamic feedback. We show that this suppression at high spatial frequencies is colocalized with the classical surround, is not dependent on the relative orientation of the center and surround stimuli, and that the cortical component of this suppression is divisive. We propose that the role of this suppression at high spatial frequencies is to restrict the response to large stimuli composed of high spatial frequencies.
Survey of Obstetrician-Gynecologists about Giardiasis
Authors: Krueger Amy , Schulkin Jay , Jones Jeffrey L.
Published: June 2007

Giardiasis is one of the most common parasitic diseases in the United States with over 15 400 cases reported in 2005. A survey was conducted by The American College of Obstetricians and Gynecologists (ACOG) in collaboration with the Centers for Disease Control and Prevention (CDC) to evaluate the knowledge of obstetricians and gynecologists regarding the diagnosis and treatment of giardiasis. The questionnaire was distributed to a random sample of 1200 ACOG fellows during February through June of 2006. Five hundred and two (42%) responded to the survey. The respondents showed good general knowledge about diagnosis, transmission, and prevention; however, there was some uncertainty about the treatment of giardiasis and which medications are the safest to administer during the first trimester of pregnancy.
Metabolic Memory Phenomenon and Accumulation of Peroxynitrite in Retinal Capillaries
Authors: Kowluru Renu A. , Kanwar Mamta , Kennedy Alexander
Published: June 2007

Aim. Diabetic retinopathy resists reversal after good glycemic control (GC) is reinitiated, and preexisting damage at the time of intervention is considered as the major factor in determining the outcome of the GC. This study is to investigate the role of peroxynitrite accumulation in the retinal capillaries in the failure of retinopathy to reverse after reestablishment of GC, and to determine the effect of this reversal on the activity of the enzyme responsible for scavenging mitochondrial superoxide, MnSOD. Methods. In streptozotocin‐diabetic rats, 6 months of poor glycemic control (PC, glycated hemoglobin, GHb > 12.0%) was followed by 6 additional months of GC (GHb about 6%). The trypsin‐digested retinal microvessels were prepared for immunostaining of nitrotyrosine (a measure of peroxynitrite) and for counting the number of acellular capillaries (a measure of histopathology). The retina from the other eye was used to quantify nitrotyrosine concentration, MnSOD activity and the total antioxidant capacity. Results.
Reversal of hyperglycemia after 6 months of PC had no significant effect on nitrotyrosine concentration in the retina, on the nitrotyrosine‐positive retinal capillary cells and on the number of acellular capillaries; the values were similar in PC‐GC and PC groups. In the same rats retinal MnSOD activity remained inhibited and the total antioxidant capacity was subnormal 6 months after cessation of PC. Conclusions. Peroxynitrite accumulation in the retinal microvasculature, the site of histopathology, fails to normalize after reversal of hyperglycemia, and superoxide remains inadequately scavenged. This failure of reversal of peroxynitrite accumulation could be, in part, responsible for the resistance of diabetic retinopathy to reverse after termination of PC.
Dynamical Simulation and Statistical Analysis of Velocity Fluctuations of a Turbulent Flow behind a Cube
Authors: Oliveira T. F. , Miserda R. B. , Cunha F. R.
Published: June 2007

A statistical approach for the treatment of turbulence data generated by computer simulations is presented. A model for compressible flows at large Reynolds numbers and low Mach numbers is used for simulating a backward-facing step airflow. A scaling analysis has justified the commonly used assumption that the internal energy transport due to turbulent velocity fluctuations and the work done by the pressure field are the only relevant mechanisms needed to model subgrid-scale flows. From the numerical simulations, the temporal series of velocities are collected for ten different positions in the flow domain, and are statistically treated. The statistical approach is based on probability averages of the flow quantities evaluated over several realizations of the simulated flow. We look at how long of a time average is necessary to obtain well-converged statistical results. For this end, we evaluate the mean-square difference between the time average and an ensemble average as the measure of convergence. This is an interesting question since the validity of the ergodic hypothesis is implicitly assumed in every turbulent flow simulation and its analysis. The ergodicity deviations from the numerical simulations are compared with theoretical predictions given by scaling arguments. A very good agreement is observed. Results for velocity fluctuations, normalized autocorrelation functions, power spectra, probability density distributions, as well as skewness and flatness coefficients are also presented.
Detection of Elevated Signaling Amino Acids in Human Diabetic Vitreous by Rapid Capillary Electrophoresis
Authors: Lu Miao-Jen , Pulido Jose S. , McCannel Colin A. , Pulido Jose E. , Hatfield R. Mark , Dundervill Robert F. , Shippy Scott A.
Published: June 2007

Elevated glutamate is implicated in the pathology of PDR. The ability to rapidly assess the glutamate and amino acid content of vitreous provides a more complete picture of the chemical changes occurring at the diabetic retina and may lead to a better understanding of the pathology of PDR. Vitreous humor was collected following vitrectomies of patients with PDR and control conditions of macular hole or epiretinal membrane. A capillary electrophoresis method was developed to quantify glutamate and arginine. The analysis is relatively fast (<6 minutes) and utilizes a poly(ethylene)oxide and sodium dodecylsulfate run buffer. Both amino acid levels show significant increases in PDR patients versus controls and are comparable to other reports. The levels of vitreal glutamate vary inversely with the degree of observed hemorrhage. The results demonstrate a rapid method for assessment of a number of amino acids to characterize the chemical changes at the diabetic retina to better understand tissue changes and potentially identify new treatments.
Dielectric Polarization and Particle Shape Effects
Authors: Sihvola Ari
Published: June 2007

This article reviews polarizability properties of particles and clusters. Especially the effect of surface geometry is given attention. The important parameter of normalized dipolarizability is studied as function of the permittivity and the shape of the surface of the particle. For nonsymmetric particles, the quantity under interest is the average of the three polarizability dyadic eigenvalues. The normalized polarizability, although different for different shapes, has certain universal characteristics independent of the inclusion form. The canonical shapes (sphere, spheroids, ellipsoids, regular polyhedra, circular cylinder, semisphere, double sphere) are studied as well as the correlation of surface parameters with salient polarizability properties. These geometrical and surface parameters are essential in the material modeling problems in the nanoscale.
A Note on the Regularity of the Solutions to Two Variational Inequalities Involving a Pseudodifferential Operator
Authors: Cooper Randolph G.
Published: June 2007

The regularity of solutions to variational inequalities involving local operators has been studied extensively. Less attention has been paid to those involving nonlocal pseudodifferential operators. We present two regularity results for such problems.