bluuebunny/crossref_metadata_2025 huggingface dataset:
Methapyrilene Toxicity: Anchorage of Pathologic Observations to Gene Expression Alterations
Authors: Hamadeh Hisham K. , Knight Brian L. , Haugen Astrid C. , Sieber Stella , Amin Rupesh P. , Bushel Pierre R. , Stoll Raymond , Blanchard Kerry , Jayadev Supriya , Tennant Raymond W. , Cunningham Michael L. , Afshari Cynthia A. , Paules Richard S.
Published: October 2002

Methapyrilene (MP) exposure of animals can result in an array of adverse pathological responses including hepatotoxicity. This study investigates gene expression and histopathological alterations in response to MP treatment in order to 1) utilize computational approaches to classify samples derived from livers of MP treated rats based on severity of toxicity incurred in the corresponding tissue, 2) to phenotypically anchor gene expression patterns, and 3) to gain insight into mechanism(s) of methapyrilene hepatotoxicity. Large-scale differential gene expression levels associated with the exposure of male Sprague—Dawley rats to the rodent hepatic carcinogen MP for 1, 3, or 7 days after daily dosage with 10 or 100 mg/kg/day were monitored. Hierarchical clustering and principal component analysis were successful in classifying samples in agreement with microscopic observations and revealed low-dose effects that were not observed histopathologically. Data from cDNA microarray analysis corroborated observed histopathological alterations such as hepatocellular necrosis, bile duct hyperplasia, microvesicular vacuolization, and portal inflammation observed in the livers of MP exposed rats and provided insight into the role of specific genes in the studied toxicological processes.
Fixation of Testes and Eyes Using a Modified Davidson's Fluid: Comparison with Bouin's Fluid and Conventional Davidson's Fluid
Authors: Latendresse John R. , Warbrittion Alan R. , Jonassen Henning , Creasy Dianne M.
Published: October 2002

Most recent revisions of regulatory guidelines for testing effects of chemicals on reproduction recommend Bouin's fluid (BF) or a “comparable fixative” instead of formalin to preserve the morphologic detail of testes for histopathological evaluation. However, picric acid in BF is a health and safety hazard, as well as a laboratory waste disposal problem. Furthermore, use of BF is labor intensive, requiring multiple alcohol rinses to remove picric acid for optimum preservation and immunohistochemical (IHC) detection of testicular antigens that may potentially be used to identify and quantify cells and functional proteins with critical roles in spermatogenesis. Recently a modified Davidson's fluid (mDF) has been reported as an alternative to BF to fix testes for routine histopathological examination. This study compared the overall histomorphologic clarity and the immunoand histochemical staining of testicular specimens fixed in BF and mDF. Additionally, because conventional Davidson's fixative (DF) is used routinely for optimum fixation of eyes, preservation of ocular histomorphology by DF and mDF was compared. mDF resulted in noticeably less shrinkage of the seminiferous tubules and superior overall morphologic detail compared to BF. Unlike DF, the mDF also supported excellent staining of acrosomes with periodic acid-Schiff (PAS) reagent when staging of spermatogenesis was required. IHC detection of androgen receptor and PCNA (to directly and indirectly identify Sertoli cells) as well as protein gene product 9.5 (to label spermatogonia) was superior in mDF compared to BF-fixed specimens. For histopathological examination of the eye, apposition and preservation of rods and cones, and nuclear layers of the retina were slightly inferior with mDF compared to DF. This paper has demonstrated that mDF provides comparable, and in many respects superior preservation of the testes to that of BF, both for IHC staining and for detailed histopathological examination. It also provides an acceptable fixative for eyes, although the quality of cellular preservation is inferior to that of DF.
Ara‐C‐ and daunorubicin‐induced recruitment of Lyn in sphingomyelinase‐enriched membrane rafts
Authors: Grazide Solène , Maestre Nicolas , Veldman Robert Jan , Bezombes Christine , Maddens Stéphane , Levade Thierry , Laurent Guy , Jaffrézou Jean‐pierre
Published: October 2002

Induction of apoptosis by DNA‐damaging agents such as 1‐β‐D‐arabinofuranosylcytosine (Ara‐C) includes the activation of Lyn protein tyrosine kinase. We have previously established that Ara‐C‐induced activation of Lyn results in its binding to a neutral sphingomyelinase (SMase) and is requisite for its stimulation and the induction of apoptosis in U937 cells. However, the spacio‐temporal organization of these events is unclear. This study demonstrates that part of the total cellular SMase activity is sequestered in sphingomyelin‐enriched plasma membrane microdomains (rafts). Under Ara‐C and daunorubicin (DNR) treatment, Lyn is rapidly activated and translocated into rafts. The compartmentalization of Lyn (as well as neutral SMase activation and apoptosis) induced by these drugs was blocked by the tyrosine kinase inhibitor herbimycin A and raft disruption. In conclusion, this study establishes that DNA‐damaging agents such as Ara‐C and DNR rapidly induce Lyn activation and its translocation into membrane rafts. This in turn leads to neutral SMase activation and raft‐associated sphingomyelin hydrolysis with the concomitant generation of the proapoptotic lipid second messenger, ceramide. The apparent topological partitioning between DNA damage and apoptosis signaling (integrated into specialized plasma membrane domains) is discussed.
Crystal structures of leukotriene A4 hydrolase in complex with captopril and two competitive tight‐binding inhibitors
Authors: Thunnissen Marjolein M.G.M. , Andersson Björn , Samuelsson Bengt , Wong Chi‐huey , Haeggström Jesper Z.
Published: October 2002

Leukotriene (LT) A4 hydrolase/aminopeptidase is a bifunctional zinc enzyme that catalyzes the final step in the biosynthesis of LTB4, a potent chemoattractant and immune modulating lipid mediator. Here, we report a high‐resolution crystal structure of LTA4 hydrolase in complex with captopril, a classical inhibitor of the zinc peptidase angiotensin‐converting enzyme. Captopril makes few interactions with the protein, but its free thiol group is bound to the zinc, apparently accounting for most of its inhibitory action on LTA4 hydrolase. In addition, we have determined the structures of LTA4 hydrolase in complex with two selective tight‐binding inhibitors, a thioamine and a hydroxamic acid. Their common benzyloxyphenyl tail, designed to mimic the carbon backbone of LTA4, binds into a narrow hydrophobic cavity in the protein. The free hydroxyl group of the hydroxamic acid makes a suboptimal, monodentate complex with the zinc, and strategies for improved inhibitor design can be deduced from the structure. Taken together, the three crystal structures provide the molecular basis for the divergent pharmacological profiles of LTA4 hydrolase inhibitors. Moreover, they help define the binding pocket for the fatty acid‐derived epoxide LTA4 as well as the subsites for a tripeptide substrate, which in turn have important implications for the molecular mechanisms of enzyme catalyses.
Negative regulatory role of overexpression of PLCγ1in the expression of early growth response 1 gene in rat 3Y1 fibroblasts
Authors: Shin Soon Young , Ko Jesang , Chang Jong‐Soo , Min Do Sik , Choi Chan , Bae Sun Sik , Kim Myung Jong , Hyun Dae Sung , Kim Jung‐Hye , Han Mi Young , Kim Young‐Ho , Kim Yong Sik , Na Doe Sun , Suh Pann‐Ghill , Lee Young Han
Published: October 2002

The early growth response 1 (Egr‐1) gene product is a transcription factor that functions as an oikis factor. Loss of Egr‐1 expression is closely associated with tumor formation. Phospholipase Cγ1 (PLCγ1) is overexpressed in some tumors, and its overexpression causes anchorage‐independent growth. Here we report that overexpression of PLCγ1 and SH2‐SH3 domain of PLCγ1 decreased induction of Egr‐1 and the Egr‐1‐regulated genes TSP‐1 and PAI‐1. Results from the nuclear run‐on assay and transfection experiment with the proximal 455 base pair region of the Egr‐1 promoter (‐454 to +1) showed that Egr‐1 transcriptional activity was suppressed in PLCγ1–3Y1 cells whereas decay of Egr‐1 mRNA was similar in both cell lines. Serum response element‐and ternary complex factor Elk‐1‐mediated transcriptional activation of the reporter gene in response to EGF were also inhibited in PLCγ1–3Y1 cells. Pretreatment with the protein synthesis inhibitor cycloheximide (CHX) partially abrogated the serum‐induced suppression of Egr‐1 transcription in PLCγ1–3Y1 cells, suggesting that a CHX‐sensitive factor(s) is involved in the suppression of Egr‐1 transcription in PLCγ1–3Y1 cells. Our results demonstrated that overexpression of PLCγ1 functions as a negative modulator of the tumor suppressor Egr‐1 gene expression, possibly through inhibition of Elk‐1‐dependent transcriptional activity.—Shin, S. Y., Ko, J., Chang, J.‐S., Min, D. S., Choi, C., Bae, S. S., Kim, M. J., Hyun, D. S., Kim, J.‐H., Han, M. Y., Kim, Y.‐H., Kim, Y. S., Na, D. S., Suh, P.‐G., Lee, Y. H. Negative regulatory role of overexpression of PLCγ1 in the expression of early growth response 1 gene in rat 3Y1 fibroblasts. FASEB J. 16, 1504–1514 (2002)
Fatty acid augmentation of the cardiac slowly activating delayed rectifier current (IKs) is conferred by hminK
Authors: Doolan Gavin K. , Panchal Rekha G. , Fonnes Eva L. , Clarke Alison L. , Williams David A. , Petrou Steven
Published: October 2002

The mechanism by which dietary fatty acids confer protection against cardiac arrhythmias and sudden cardiac death is not resolved. Here, we study the effects of several known cardioprotective and arrhythmogenic fatty acids on the slowly activating delayed rectifier potassium current (IKs), which is responsible for the repolarization phase of the cardiac action potential. cRNAs encoding either or both of the two subunits, KvLQT1 and hminK, that together produce IKs, were injected into Xenopus oocytes, and the effects of various fatty acids were determined. Docosahexaenoic acid (DHA) significantly augmented IKs as did the short‐chained fully saturated lauric acid, and to a lesser extent the cis‐unsaturated oleic acid. Eicosapentaenoic acid (EPA) was without significant effect on current magnitude, although it reduced the rate of activation. These results suggest that not all “antiarrhythmic” fatty acids target the same channel. To examine the role of hminK in this response, KvLQT1 was expressed alone. In this case, DHA, lauric acid, and oleic acid did not augment current, suggesting that hminK confers fatty acid sensitivity to IKs.
Nitric oxide promotes intracellular calcium release from mitochondria in striatal neurons
Authors: Horn Thomas F. W. , Wolf Gerald , Duffy Steven , Weiss Samuel , Keilhoff Gerburg , MacVicar Brian A.
Published: October 2002

Overproduction of nitric oxide by NMDA receptor stimulation is implicated in calcium deregulation and neurodegeneration of striatal neurons. We investigated the involvement of nitric oxide (NO) in inducing intracellular calcium release and in modifying calcium transients evoked by NMDA. NO application (4–10 fM) reversibly and repeatedly increased the intracellular calcium concentration [Ca2+]i in Fura‐2‐or fluo‐3‐loaded cultured mouse striatal neurons. NO‐induced [Ca2+]i responses persisted in the absence of extracellular calcium, indicating that Ca2+ was released from intracellular stores. The source of calcium was distinct from [Ca2+]i‐activated (ruthenium red and ryanodine sensitive) or IP3‐activated (thapsigargin‐sensitive) Ca2+ stores and was not dependent on cGMP production because a cell permeant analog, 8‐bromo‐cGMP, did not increase basal [Ca2+]i. Glucose removal potentiated the NO‐induced release of [Ca2+]i. In contrast, pretreatment with either the mitochondrial uncoupler carbonyl cyanide m‐chlorophenylhydrazone or cyclosporin A, a blocker of the mitochondrial permeability transition pore, prevented the [Ca2+]i increase after NO. The rise in [Ca2+]i during NO exposure was preceded by a decrease in mitochondrial membrane potential that was partly reversible during washout. Repeated applications of NMDA induced irreversible [Ca2+]i responses in a subpopulation of striatal cells that were greatly reduced by the NOS inhibitor NW‐nitro‐L‐arginine. Calcium transients were prolonged by conjoint application of NMDA and NO. We conclude that NMDA‐evoked [Ca2+]i transients are modulated by endogenous NO production, which leads to release of calcium from the mitochondrial pool. An NO‐activated mitochondrial permeability transition pore may lead to cell death after overstimulation of NMDA receptors.—Horn, T. F. W., Wolf, G., Duffy, S., Weiss, S., Keilhoff, G., MacVicar, B. A. Nitric oxide promotes intracellular calcium release from mitochondria in striatal neurons. FASEB J. 16, 1611–1622 (2002)
The PDZ‐scaffold protein INAD abolishes apparent store‐dependent regulation of the light‐activated cation channel TRP
Authors: Harteneck Christian , Kuchta Sabina Naranjo , Huber Armin , Paulsen Reinhard , Schultz Günter
Published: October 2002

In fly photoreceptor cells, light initiates a G protein‐coupled phospholipase Cβ‐dependent signaling cascade that results in the depolarization of the cell membrane, which is mediated by the cation channels TRP and TRPL. Together with phospholipase Cβ and an eye‐specific protein kinase C, TRP is tethered to the scaffolding protein INAD, which forms a multimolecular signaling complex. Divergent data from expressed TRP and studies from photoreceptor cells have brought up a controversy whether or not a capacitative calcium entry (CCE) mechanism is involved in the Drosophila phototransduction pathway. Our initial characterization of TRP from photoreceptors of Calliphora vicina supported the hypothesis of a CCE mechanism, as heterologously expressed TRP was stimulated after application of thapsigargin. The situation changed when the PDZ domain protein INAD was coexpressed with TRP. In cells coexpressing TRP and INAD, no calcium entry was detectable on application of store depletion protocols. Suppression of CCE by INAD was not observed when the described interaction was disrupted by mutations in TRP and INAD. Our data show that apparent activation of TRP by CCE is abolished by INAD. Within the complex, the proteins necessary for phototransduction mutually influence their activities. The results support the hypothesis of a store‐independent activation of TRP.
Severely reduced neutrophil adhesion and impaired host defense against fecal and commensal bacteria in CD18–/–P‐selectin–/–double null mice
Authors: Forlow Stephen Bradley , Foley Patricia L. , Ley Klaus
Published: October 2002

Leukocyte recruitment to sites of inflammation requires the functions of selectins and integrins. P‐selectin null (CD62P–/–) mice show a mild and CD18 null (CD18–/–) mice a more severe neutrophil recruitment defect in some inflammatory models. To investigate the possible cooperative interactions between CD18 integrins and P‐selectin in mediating neutrophil recruitment, we generated CD18–/–CD62P–/–double null mice. CD18–/–CD62P–/–mice were apparently normal at weaning and fertile but later failed to gain weight, showed increased susceptibility to infection by fecal and commensal bacteria, and survived only 5–6 months. Some CD18–/–CD62P–/–mice showed severe spontaneous skin lesions; most showed neutrophil infiltration in the lungs and liver, and positive bacterial cultures from internal organs. The number and velocity of rolling leukocytes in tumor necrosis factor a treated venules of CD18–/–CD62P–/–mice was similar to those in wild‐type mice, but neutrophil adhesion was severely reduced. Only 25% of adhered leukocytes were neutrophils in CD18–/–CD62P‐/mice vs. >90% in wild‐type, CD62P–/–, and CD18–/–single mutants. Our data show that removing both P‐selectin and CD18 integrins from mice leads to severe neutrophil recruitment defects and spontaneous pathology.—Forlow, S. B., Foley, P. L., Ley, K. Severely reduced neutrophil adhesion and impaired host defense against fecal and commensal bacteria in CD18–/–P‐selectin–/–double null mice. FASEB J. 16, 1488–1496 (2002)
Augmentation of cardiac contractility with no change in L‐type Ca2+ current in transgenic mice with a cardiac‐directed expression of the human adenylyl cyclase type 8 (AC8)
Authors: Georget Marie , Mateo Philippe , Vandecasteele Grégoire , Jurevičius Jonas , Lipskaia Larissa , Defer Nicole , Hanoune Jacques , Hoerter Jacqueline , Fischmeister Rodolphe
Published: October 2002

The β‐adrenergic cascade is severely impaired in heart failure (HF), in part because of a reduction in the activity of the two dominant cardiac adenylyl cyclase (AC) isoforms, AC5 and AC6. Hence, cardiac‐directed AC overexpression is a conceivable therapeutic strategy in HF. In this study, we explored the consequences at the cellular and organ level of a cardiac‐directed expression of the human AC8 in the transgenic mouse line AC8TG. Unlike AC5 and AC6, which are inhibited by intracellular Ca2+, AC8 is stimulated by Ca2+‐calmodulin. Langendorff perfused hearts from AC8TG mice had a twofold higher left ventricular systolic pressure, a 40% faster heart rate, a 37% faster relaxation, and a 30% higher sensitivity to external Ca2+ than nontransgenic control mice (NTG). Cell shortening measured in isolated ventricular myocytes developed 22% faster and relaxed 43% faster in AC8TG than in NTG mice. Likewise, Ca2+ transients measured in fluo‐3 AM‐loaded myocytes were 30% higher and relaxed 24% faster in AC8TG compared with NTG mice. In spite of the large increase in Ca2+ transients and contraction, expression of AC8 had no effect on the whole‐cell L‐type Ca2+ current (ICa,L) amplitude. Moreover, ICa,L was unchanged even when AC8 was activated by raising intracellular Ca2+. Thus, cardiac expression of AC8 leads to an increase in cAMP that activates specifically Ca2+ uptake into the sarcoplasmic reticulum but not Ca2+ influx at the sarcolemma, suggesting a strong compartmentation of the cAMP signal.
RETRACTED: NCX‐4016, a nitric oxide‐releasing aspirin, protects endothelial cells against apoptosis by modulating mitochondrial function
Authors: Fiorucci Stefano , Mencarelli Andrea , Mannucci Roberta , Distrutti Eleonora , Morelli Antonio , del Soldato Piero , Moncada Salvador
Published: October 2002

We investigated the effect of a nitric oxide (NO)‐releasing derivative of aspirin (NCX‐4016) on a mitochondria‐dependent model of apoptosis in human umbilical endothelial cells (HUVEC). Exposure of HUVEC to staurosporine caused a progressive fall in mitochondrial membrane potential (∆ψm) and apoptosis. Exposure to an NO donor, (z)‐1‐[2‐(2‐aminoethyl)‐N‐(2ammonioethyl)amino]diazen‐1‐ium‐1,2‐diolate (DETA‐NO), caused an early (1–3h) hyperpolarization of ∆ψm and reduction of apoptosis that was followed (at 4–8 h) by an accelerated collapse of ∆ψm and cell death. In contrast, treatment with NCX‐4016, but not with aspirin or a non‐NO‐releasing analogue of NCX‐4016, protected HUVEC against the apoptotic actions of staurosporine for up to 8 h. Confocal microscopy demonstrated that although NCX4016 released NO in subcellular compartments, DETA‐NO caused a generalized increase in cytosolic fluorescence. Exposure to DETA‐NO resulted in a rapid and profound inhibition of cell respiration (78.3 ± 6.4%), whereas NCX‐4016 caused a less pronounced reduction in oxygen consumption (43.5 ± 5.3%). Staurosporine caused a time‐dependent activation of proapoptotic caspases. NCX‐4016 prevented this activation, whereas DETA‐NO failed to inhibit caspase activity. In contrast to DETA‐NO, NCX‐4016 did not increase mitochondrial oxidative stress. These data demonstrated that NCX‐4016 conveys NO directly inside endothelial cells and modulates mitochondrial function.
Angiogenesis stimulated by PDGF‐CC, a novel member in the PDGF family, involves activation of PDGFR‐aa and ‐ap receptors
Authors: Cao Renhai , Bråkenhielm Ebba , Li Xuri , Pietras Kristian , Widenfalk Johan , Östman Arne , Eriksson Ulf , Cao Yihai
Published: October 2002

A newly discovered PDGF isoform, PDGF‐CC, is expressed in actively angiogenic tissues such as placenta, some embryonic tissues, and tumors. We test the possibility that PDGF‐CC promotes angiogenesis in vivo. The core domain (mature form) of human PDGF‐CC is sufficiently potent to stimulate neovascularization in the mouse cornea. The corneal angiogenic response induced by PDGF‐CC is robust although the area of neovascularization is smaller than those of FGF‐2‐and VEGF‐stimulated angiogenesis. Similarly, PDGF‐BB and PDGF‐AB induce angiogenic responses virtually indistinguishable from PDGF‐CCstimulated vessels. In contrast, PDGF‐AA displays only a weak angiogenic response in the mouse cornea. Although there was no significant difference in incorporation of mural cells to the newly formed blood vessels induced by PDGF‐BB and ‐CC, the percentage of mural cell positive vessels induced by PDGF‐AA was greater than those induced by FGF‐2, PDGF‐BB, and PDGF‐CC. In the developing chick embryo, PDGF‐CC induced branch sprouts from established blood vessels. In PDGF receptor‐transfected endothelial cells, PDGF‐CC activated the PDGF receptor alpha subunit (PDGFR‐a). PDGF‐CC, but not PDGF‐AA, was able to activate PDGFR‐p receptor in endothelial cells that coexpress both α and β forms of receptors. Thus, the PDGF‐CC‐mediated angiogenic response is most likely transduced by PDGF‐aa and ‐ap receptors. These data demonstrate that the PDGF family is a complex and important group of proangiogenic factors.—Cao, R., Bråkenhielm, E., Li, X., Pietras, K., Widenfalk, J, Östman, A., Eriksson, U., Cao, Y. Angiogenesis stimulated by PDGF‐CC, a novel member in the PDGF family, involves activation of PDGFR‐aa and ‐ap receptors. FASEB J. 16, 1575–1583 (2002)
The Genetic Structure of Cloninger's Seven‐Factor Model of Temperament and Character in a Japanese Sample
Authors: Ando Juko , Ono Yutaka , Yoshimura Kimio , Onoda Naoko , Shinohara Manabu , Kanba Shigenobu , Asai Masahiro
Published: October 2002

ABSTRACT Theoretical assumptions regarding the genetic and environmental structure of personality proposed in Cloninger's seven‐factor model of temperament and character were verified in a Japanese sample by using the twin method. The Temperament and Character Inventory (TCI) was administered to 296 twin pairs ranging in age from 14 to 28 years old. Among four temperament dimensions (novelty seeking [NS], harm avoidance [HA], reward dependence [RD], and persistence [PS]), HA and PS showed significant additive genetic contributions and no shared environmental effect, supporting the original theoretical assumption. NS and RD could be explained by either genetic or shared environmental factors with nonshared environment. All three character dimensions (cooperativeness [CO], self‐directedness [SD], and self‐transcendence [ST]) could be explained exclusively by additive contributions and no shared environmental effect. Multivariate genetic analysis indicated that there were no significant associations between NS, HA, and RD, as the theory predicts, and the genetic components of PS, SD, and CO were derived from those of the temperament dimensions. The fourth genetic component, which had a substantial load specifically on ST and overlapped with PS, was identified. Although most of the nonshared environmental effects were trait‐specific, the phenotypic correlation between NS and HA could be explained by nonshared environmental overlap.
Truncation Analysis of TatA and TatB Defines the Minimal Functional Units Required for Protein Translocation
Authors: Lee Philip A. , Buchanan Grant , Stanley Nicola R. , Berks Ben C. , Palmer Tracy
Published: October 2002

The TatA and TatB proteins are essential components of the twin arginine protein translocation pathway in
Escherichia coli
. C-terminal truncation analysis of the TatA protein revealed that a plasmid-expressed TatA protein shortened by 40 amino acids is still fully competent to support protein translocation. Similar truncation analysis of TatB indicated that the final 30 residues of TatB are dispensable for function. Further deletion experiments with TatB indicated that removal of even 70 residues from its C terminus still allowed significant transport. These results imply that the transmembrane and amphipathic helical regions of TatA and TatB are critical for their function but that the C-terminal domains are not essential for Tat transport activity. A chimeric protein comprising the N-terminal region of TatA fused to the amphipathic and C-terminal domains of TatB supports a low level of Tat activity in a strain in which the wild-type copy of either
tatA
or
tatB
(but not both) is deleted.
Evidence for a Type III Secretion System in
Aeromonas salmonicida
subsp.
salmonicida
Authors: Burr Sarah E. , Stuber Katja , Wahli Thomas , Frey Joachim
Published: October 2002

Aeromonas salmonicida
subsp.
salmonicida
, the etiological agent of furunculosis, is an important fish pathogen. We have screened this bacterium with a broad-host-range probe directed against
yscV
, the gene that encodes the archetype of a highly conserved family of inner membrane proteins found in every known type III secretion system. This has led to the identification of seven open reading frames that encode homologues to proteins functioning within the type III secretion systems of
Yersinia
species. Six of these proteins are encoded by genes comprising a
virA
operon. The
A. salmonicida
subsp.
salmonicida yscV
homologue,
ascV
, was inactivated by marker replacement mutagenesis and used to generate an isogenic
ascV
mutant. Comparison of the extracellular protein profiles from the
ascV
mutant and the wild-type strain indicates that
A. salmonicida
subsp.
salmonicida
secretes proteins via a type III secretion system. The recently identified ADP-ribosylating toxin AexT was identified as one such protein. Finally, we have compared the toxicities of the wild-type
A. salmonicida
subsp.
salmonicida
strain and the
ascV
mutant against RTG-2 rainbow trout gonad cells. While infection with the wild-type strain results in significant morphological changes, including cell rounding, infection with the
ascV
mutant has no toxic effect, indicating that the type III secretion system we have identified plays an important role in the virulence of this pathogen.
A Polysaccharide Deacetylase Gene (
pdaA
) Is Required for Germination and for Production of Muramic δ-Lactam Residues in the Spore Cortex of
Bacillus subtilis
Authors: Fukushima Tatsuya , Yamamoto Hiroki , Atrih Abdelmadjid , Foster Simon J. , Sekiguchi Junichi
Published: October 2002

The predicted amino acid sequence of
Bacillus subtilis yfjS
(renamed
pdaA
) exhibits high similarity to those of several polysaccharide deacetylases. β-Galactosidase fusion experiments and results of Northern hybridization with sporulation sigma mutants indicated that the
pdaA
gene is transcribed by Eσ
G
RNA polymerase.
pdaA
-deficient spores were bright by phase-contrast microscopy, and the spores were induced to germination on the addition of
l
-alanine. Germination-associated spore darkening, a slow and partial decrease in absorbance, and slightly lower dipicolinic acid release compared with that by the wild-type strain were observed. In particular, the release of hexosamine-containing materials was lacking in the
pdaA
mutant. Muropeptide analysis indicated that the
pdaA
-deficient spores completely lacked muramic δ-lactam. A
pdaA-gfp
fusion protein constructed in strain 168 and
pdaA
-deficient strains indicated that the protein is localized in
B. subtilis
spores. The biosynthetic pathway of muramic δ-lactam is discussed.
Protein Sequences and Cellular Factors Required for Polar Localization of a Histidine Kinase in
Caulobacter crescentus
Authors: Sciochetti Stephen A. , Lane Todd , Ohta Noriko , Newton Austin
Published: October 2002

The
Caulobacter crescentus
sensor kinase DivJ is required for an early cell division step and localizes at the base of the newly formed stalk during the G1-to-S-phase transition when the protein is synthesized. To identify sequences within DivJ that are required for polar localization, we examined the ability of mutagenized DivJ sequences to direct localization of the green fluorescent protein. The effects of overlapping C-terminal deletions of DivJ established that the N-terminal 326 residues, which do not contain the kinase catalytic domain, are sufficient for polar localization of the fusion protein. Internal deletions mapped a shorter sequence between residues 251 and 312 of the cytoplasmic linker that are required for efficient localization of this sensor kinase. PleC kinase mutants, which are blocked in the swarmer-to-stalked-cell transition and form flagellated, nonmotile cells, also fail to localize DivJ. To dissect the cellular factors involved in establishing subcellular polarity, we have examined DivJ localization in a
pleC
mutant suppressed by the
sokA301
allele of
ctrA
and in a
pleD
mutant, both of which display a supermotile, stalkless phenotype. The observation that these Mot
+
strains localize DivJ to a single cell pole indicate that localization may be closely coupled to the gain of motility and that normal stalk formation is not required. We have also observed, however, that filamentous
parC
mutant cells, which are defective in DNA segregation and the completion of cell separation, are motile and still fail to localize DivJ to the new cell pole. These results suggest that formation of new sites for DivJ localization depends on events associated with the completion of cell separation as well as the gain of motility. Analysis of PleC and PleD mutants also provides insights into the function of the His-Asp proteins in cell cycle regulation. Thus, the ability of the
sokA301
allele of
ctrA
to bypass the nonmotile phenotype of the
pleC
null mutation provides evidence that the PleC kinase controls cell motility by initiating a signal transduction pathway regulating activity of the global response regulator CtrA. Analysis of the
pleD
mutant cell cycle demonstrates that disruption of the swarmer-to-stalked-cell developmental sequence does not affect the asymmetric organization of the
Caulobacter
cell cycle.
Systematic relationships inLathyrussect.Lathyrus(Fabaceae) based on amplified fragment length polymorphism (AFLP) data
Authors: Badr Abdelfattah , Shazly Hanaa El , Rabey Haddad El , Watson Linda E
Published: October 2002

Amplified fragment length polymorphisms (AFLP) were utilized to examine systematic relationships in Lathyrus L. sect. Lathyrus (Fabaceae). In addition to a parsimony-based phylogenetic tree, AFLP-based trees were constructed using Dice, Jaccard, and mean character difference coefficients to produce distance-based trees using the UPGMA and neighbor-joining methods. All trees clearly show a close relationship among accessions of the same species, confirming the monophyly of the species examined. All analyses indicate that species of the section Lathyrus are distinct from species of other sections. These findings confirm the monophyly of the section and contradict proposals to split it. They do not support the segregation of L. gorgoni in the section Gorgonia. Within the section Lathyrus, several relationships are present but are only weakly supported. The use of AFLP data to resolve systematic relationships in the genus Lathyrus is further demonstrated.Key words: Lathyrus, Fabaceae, systematics, AFLP.
Phylogeny ofSisymbrium(Brassicaceae) based on ITS sequences of nuclear ribosomal DNA
Authors: Warwick Suzanne I , Al-Shehbaz Ihsan A , Price Robert A , Sauder Connie
Published: October 2002

The genus Sisymbrium as currently circumscribed includes about 94 species disjunctly distributed in the Old (41 spp.) and the New World (53 spp.). Sisymbrium has been variously delimited, with several segregate genera proposed (subtribe Sisymbriinae) primarily for the new World taxa, including Schoenocrambe, Coelophragmus, and Mostacillastrum. Using sequence data from the internal transcribed spacers of nuclear ribosomal DNA and the 5.8S rRNA gene (collectively, ITS region), we examined the evolutionary relationships of Old and New World Sisymbrium species with its segregate genera and the validity of O.E. Schulz's classical sectional treatment of Sisymbrium. Sequence data were obtained from 33 Sisymbrium species, representing all 14 sections and two Sisymbrium species formerly assigned to segregate genera Coelophragmus and Mostacillastrum (subtribe Sisymbriinae), and two putative Sisymbrium species currently assigned to Neotorularia. Sequence data were also obtained from 26 taxa from segregate or related genera includingSchoenocrambe, Werdermannia (subtribe Sisymbriinae), eight genera in the Thelypodieae, Sibara (tribe Arabideae) and Pringlea (tribe Pringleeae), four members of the tribe Brassiceae, and three other Neotorularia species. Results from maximum parsimony analysis showed a polyphyletic origin for Sisymbrium and did not correspond well to Schulz's sectional classification. Sisymbrium species were split into three major clades: Old World Sisymbrium (including Neotorularia aculeolata, Neotorularia afghanica, and the type species of Schoenocrambe, Schoenocrambe linifolia, the sole New World member of this Old World clade); New World Sisymbrium (along with the remaining New World taxa) and designated as the New World Thelypodieae alliance; and the tribe Brassiceae ( including Sisymbrium supinum and Sisymbrium thellungii).Key words: Sisymbrium, Schoenocrambe, ITS, Thelypodieae, taxonomy, Brassicaceae.
ALTERNATIVE EXPERIMENTAL DETERMINATION OF WEAK LOCALIZATION OF LIGHT IN NANOSTRUCTURED MATERIALS
Authors: CLAYS KOEN , WOSTYN KURT , ZHAO YUXIA , PERSOONS ANDRÉ
Published: October 2002

An alternative experimental technique for the determination of weak localization of light in partially ordered nanostructured materials is proposed. The technique is based on the criterion for weak localization of light that the transport mean free path length of multiply scattered photons is reduced down to shorter than the wavelength of the light. This mean free path is calculated from the experimental dwell time of the photons in the scattering structure and by applying the photon random walk model using the diffusion approximation. The dwell time is experimentally determined by multifrequency phasefluorimetry. This technique is capable of providing corroborative intensity demodulation data that can be linked to the wavelength dependent transmission (optical bandgap) of colloidal crystals.
STIMULATED RAMAN SCATTERING IN MULTI-MODE FIBERS AND ITS APPLICATION TO BEAM CLEANUP AND COMBINING
Authors: RUSSELL TIMOTHY H. , WILLIS SHAWN M. , CROOKSTON MATTHEW B. , ROH WON B.
Published: October 2002

Laser beam cleanup properties of stimulated Raman scattering (SRS) in a multi-mode fiber have been characterized. It is shown that a fiber, which supports propagation of a highly aberrated pump beam, can generate a Gaussian-like Stokes beam consisting of one or more orders of Stokes components. The beam cleanup properties are found to be similar to those of stimulated Brillouin scattering, which are briefly reviewed herein. The dramatic enhancement in beam quality achievable through SRS clearly demonstrates the potential utility of fiber-based Raman beam cleanup/combining devices for laser brightness scaling.
LATTICE-ISOMORPHIC GROUPS, AND INFINITE ABELIAN G-COGALOIS FIELD EXTENSIONS
Authors: ALBU TOMA , BASARAB ŞERBAN
Published: October 2002

The aim of this paper is to provide a proof of the following result claimed by Albu (Infinite field extensions with Galois–Cogalois correspondence (II), Revue Roumaine Math. Pures Appl. 47 (2002), to appear): The Kneser group Kne (E/F) of an Abelian G-Cogalois extension E/F and the group of continuous characters Ch(Gal (E/F)) of its Galois group Gal (E/F) are isomorphic (in a noncanonical way). The proof we give in this paper explains why such an isomorphism is expected, being based on a classical result of Baer (Amer. J. Math.61 (1939), 1–44) devoted to the existence of group isomorphisms arising from lattice isomorphisms of their lattices of subgroups.
Gear lubrication—a review
Authors: Olver A. V.
Published: October 2002

The lubrication of gear teeth is reviewed including some key aspects of recent theoretical research and current practice. A simple estimate of the thickness of the lubricating film in a typical pair of spur gears is presented on the basis of classical smooth-body isothermal, elastohydrodynamic lubrication theory. The deficiencies of this simple calculation are then discussed; these include roughness, friction, churning, starvation and contamination, all common features of practical gearing. Three simple methods are described for estimating the tooth temperature and its consequent effect on film thickness.
Newtonian or shear-thinning oils for screw-type compressors?
Authors: Kauder K
Published: October 2002

With the application of oils with useful dynamic viscosities and special oil characteristics, operators of screw-type compressors have the possibility of decreasing the power consumption and to improve the machine's behaviour at various speeds. The idea was to adapt the oil viscosity to the compressor's rotational speed in order to reduce power loss. On the basis of this idea, research was carried out on shear-thinning oils in screw-type compressors. Thus this article is based on the theory that viscosity regulation, related to rotational speed, can be used to improve the sealing effect of the clearances at lower speeds and to decrease hydrodynamic losses at higher speeds. Using a Newtonian oil this aim cannot be achieved. Only shear-thinning oils can help to solve this problem. This article will deal with this subject.
Thermohydrodynamic performance of journal bearing with partial reverse flow and finger-type cavitation
Authors: Hatakenaka K , Tanaka M
Published: October 2002

Firstly, a new calculation method is presented to solve the energy equation of the oil film in plain bearing in analysing the thermohydrodynamic performance of the bearing. The energy equation is made discrete by means of the control volume method widely used in computational fluid dynamics (CFD), and the coefficients of the discretized equations are determined by means of the hybrid scheme, also widely used in CFD. This method can make it easier to obtain convergent solutions of the temperature distribution in the lubricating film, even where a large extent of the reverse flow region exists at the oil film inlet. Next, a new model is proposed to calculate the heat flow at the pad-film interface in the cavitated region. The model is based on the idea that the heat fluxes in the lubricant streams and in the cavities should be calculated separately. The thermohydrodynamic performance of a two-lobe journal bearing is calculated by means of the new method and the new model. The results are in good agreement with the measurements by Ma and Taylor.
Narrow journal bearings
Authors: Ståhl J
Published: October 2002

In this report, numerical analyses of very narrow journal bearings are presented. The pressure distribution was determined for a number of different width-diameter ratios and eccentricities. For each combination, a number of relevant dimensionless design quantities were computed. The next step was to obtain curve-fitted functions for the variation in each design quantity. The functions are intended to be used in short computer codes and as an engineering aid in the design process. Although the complexity of the functions was low, the resemblance with the numerical results was shown to be excellent.
Modified Walsh‐Hadamard sequences for DS CDMA wireless systems
Authors: Wysocki B. J. , Wysocki T. A.
Published: October 2002

We propose a simple but efficient method for modifying Walsh–Hadamard sequences to achieve correlation properties suited for asynchronous DS CDMA applications. The proposed method can be used to minimize the mean square value of aperiodic cross‐correlation or the mean square value of aperiodic autocorrelation, the maximum value of aperiodic cross‐correlation functions, merit factor or other properties of the sequence set. The important feature of the method is that it modifies correlation properties of the sequence set, while preserving their orthogonality for the perfect synchronization. The proposed method can be applied to obtain bipolar, quadri‐phase, or general polyphase sequences. Copyright © 2002 John Wiley & Sons, Ltd.
Carbon black filled conducting polymers and polymer blends
Authors: Huang Jan‐Chan
Published: October 2002

The objective of this article was to review the use of carbon black (CB) as a conductive filler in polymers and polymer blends. Important properties of CB related to its use in conducting polymers are discussed. The effects of polymer structure, molecular weight, surface tension, and processing conditions on electrical resistivity and physical properties of composites are discussed. Several percolation models applicable to CB/polymer blends are reviewed. Emphasis is placed on recent trends using polymer blends as the matrix to obtain conducting composites at a lower CB loading. A criterion for the distribution of CB in polymer blends is discussed. © 2002 Wiley Periodicals, Inc. Adv Polym Techn 21: 299–313, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.10025
An attempt at engineering the bulk properties of blends of a bitumen with polymers
Authors: Fawcett Allan H. , McNally Tony , McNally Gerry
Published: October 2002

We have taken blends of a bitumen with three homopolymers that produce systems softer than the bitumen, and to each have added small quantities of different semicrystalline polyolefins. The intention is to discover whether these will form an extensive network system within a blend with a low Tg in which crystallites create the cross‐links, as may happen with the isotactic polypropylene present in some atactic polypropylene systems. Such thermoplastic cross‐links might provide a useful feature for certain uses, such as in built‐up roofing membranes. These were found only within one blend based upon the polybutadiene, in two blends based upon chlorinated polyethylene, but in none based on the Lycra®, whose blends with LLDPEs and the HDPE flowed below the crystal melting temperature. The E′′ plots indicate the presence of many loss processes within the blends at low temperatures: the tan δ plots show other processes active up to 200°C within the soft matter. The behavior we discovered suggests that the properties of binary polymer blends are not associated solely with the components, but that, when the material is stiff or after heating, certain polymer—bitumen interactions may also be significant, and are sensitive to slight differences of structure between LLDPEs, even when present at the 3.4% level. © 2002 Wiley Periodicals, Inc. Adv Polym Techn 21: 275–286, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.10032
Work environment effects on labor productivity: An intervention study in a storage building
Authors: Niemelä Raimo , Rautio Sari , Hannula Mika , Reijula Kari
Published: October 2002

Background

Although increased attention has been focused on the relationship between occupational health and productivity, solid scientific data on this topic are sparse. The purpose of the present case study was to assess the relationship between productivity and work environment in a storage building.

Materials and Methods

The study was implemented as an intervention consisting of the renovation of a harbor storage facility. The study design consisted of a single group of employees working in the storage hall. The physical and chemical factors, perceived environment, and labor productivity were measured before and after the renovation.

Results

As a result of the renovation, thermal conditions, air quality, and lighting conditions improved notably. In addition, the employees' subjective evaluations showed the significant decrease in dissatisfaction ratings. The direct measure for the labor productivity, expressed as zinc tons/work‐hour (tn) increased about 9% after the renovation.

Discussion

We conclude that increased productivity is most likely related to the combined effect of the improved work environment, i.e., better thermal climate, reduced contaminant concentrations, and better lighting conditions. Am. J. Ind. Med. 42:328–335, 2002. © 2002 Wiley‐Liss, Inc.
Hematological changes among Chinese workers with a broad range of benzene exposures
Authors: Qu Qingshan , Shore Roy , Li Guilan , Jin Ximei , Chi Chen Lung , Cohen Beverly , Melikian Assieh A. , Eastmond David , Rappaport Stephen M. , Yin Songnian , Li Heyi , Waidyanatha Suramya , Li Yuying , Mu Ruidong , Zhang Xiaoling , Li Keqi
Published: October 2002

Background

Depression of peripheral blood cells is a well‐known indicator of benzene hematotoxicity. Previous studies of its effects on specific types of blood cells have yielded inconsistent results. We examine hematological findings and their possible relations with exposure markers validated in a recent biomarker project conducted in Tianjin, China.

Methods

Personal benzene exposures were sampled with 3‐M organic vapor monitors, and analyzed by gas chromatography. The peripheral blood cells were counted by a cell counter. The WBC differential was manually counted on a total of 900 cells by a US commercial laboratory.

Results

A total of 130 exposed workers and 51 age‐ and gender‐matched unexposed subjects were recruited in this study. Benzene exposure levels monitored on the day of biological sample collection for exposed workers ranged from 0.06 to 122 ppm. Their 4‐week average and cumulative benzene exposure levels were 0.08–54.5 ppm and 6.1–623.2 ppm‐years, respectively. Significant decreases of red blood cells (RBC), white blood cells (WBC), and neutrophils were observed and correlated with both personal benzene exposures and levels of urinary metabolites (S‐phenylmercapuric acid and t,t‐muconic acid) and albumin adducts of benzene oxide and 1,4‐benzeoquinone.

Conclusions

The depressions in RBC, WBC, and neutrophils observed in this study are not only exposure dependent, but also significantly different in the lowest exposed group (at or below 0.25 ppm) compared with unexposed subjects. The results of the present study appear to suggest that lymphocytes may not be more sensitive to chronic benzene exposure than neutrophils. Am. J. Ind. Med. 42:275–285, 2002. © 2002 Wiley‐Liss, Inc.
Alagille syndrome inherited from a phenotypically normal mother with a mosaic 20p microdeletion
Authors: Laufer‐Cahana Ayala , Krantz Ian D. , Bason Lynn D. , Lu Feng‐Min , Piccoli David A. , Spinner Nancy B.
Published: October 2002

We report an 18‐month‐old girl with Alagille syndrome, caused by a submicroscopic deletion of chromosome 20p, including the Jagged1 (JAG1) gene. FISH using a BAC probe containing JAG1 identified the deletion. Chromosomes were normal at the 550 band level. The deletion was inherited from her phenotypically normal mother who was found to have the deletion in 9/20 cells studied from peripheral blood. This is the first report of a JAG1 deletion inherited from an apparently unaffected mosaic parent. © 2002 Wiley‐Liss, Inc.
De novo complete trisomy 5p: Clinical and neuroradiological findings
Authors: Grosso Salvatore , Cioni Maddalena , Garibaldi Gianluca , Pucci Lucia , Galluzzi Paolo , Canapicchi Raffaello , Morgese Guido , Balestri Paolo
Published: October 2002

Partial or complete duplication of 5p is a rare chromosomal abnormality in which genotype‐phenotype correlation studies are hampered by other commonly associated chromosomal abnormalities. We report on a new patient in whom a complete de novo trisomy 5p in all metaphases represented the only chromosomal aberration. The present case further contributes to delineate the typical clinical picture of the trisomy 5p syndrome. Long‐term clinical follow‐up demonstrated low levels of secretory immunoglobulin A (IgA) on several occasions and likely related to the patient's recurrent respiratory infections (RRIs), a main clinical feature of the trisomy 5p syndrome. An extensive neuroradiological study detected a progressive triventricular hydrocephalus during the fist year of life with subsequent stabilization. Neuronal migration disorders were also present and probably account for the drug‐resistant epilepsy presented by the patient. © 2002 Wiley‐Liss, Inc.