bluuebunny/crossref_metadata_2025_split huggingface dataset:
LOW IN VIVO LEVELS OF HUMAN ANX7 (ANNEXIN VII) GENE EXPRESSION ARE DUE TO ENDOGENOUS INHIBITORY PROMOTER SEQUENCES
Authors: Srivastava Meera , Pollard Harvey B. 
Published: September 2002

AbstractANX7 is a Ca2+/GTP‐dependent membrane fusion protein, which is involved in regulating exocytotic secretion. While the nullizygous ANX7 (−/−) knockout mutation in the mouse is lethal, ANX7 is nonetheless the least expressed member of the annexin gene family in mammalian and lower organisms. To investigate the basis for low ANX7 expression level we have studied the human ANX7 promoter. In our early cloning studies we learned that the human ANX7 promoter lacks TATA and CCAAT boxes, but is GC rich and contains several SP1 binding sites. To study how expression of the ANX7 gene is controlled, we fused nested deletion mutants of the 5′‐flanking region to a luciferase reporter gene. We find that the maximal level of luciferase activity is obtained by a construct comprising the domain −889/+34. However, a repressor effect observed in the region between −240 and +34 is dramatically eliminated either by the inclusion of 177bp upstream sequences, or by the presence of an upstream SV40 enhancer sequences. ANX7 gene expression is also cell type specific and is subject to different transcriptional controls in different cellular environments. The fact that the SV40 enhancer sequences not only eliminates the suppression of luciferase activity in the inhibitory region of the ANX7 promoter, but also reverses the inhibitory effect of phorbol ester, suggests that endogenous cis‐acting elements or transacting factors may be responsible for the physiologically low level ofANX7 protein expression.
A NUCLEAR MATRIX PROTEIN RELATED TO INTERMEDIATE FILAMENTS PROTEINS IS A MEMBER OF THE COMPLEX BINDING ALPHOID DNAIN VITRO
Authors: Enukashvily N. I. , Lobov I. B. , Kukalev A. , Podgornaya O. I. 
Published: September 2002

AbstractA complex of three proteins (of 80, 70, 58kDa—p80, p70, and p58, respectively) with the ability to bind alphoid DNA (α‐satDNA) was revealed by gel mobility shift assay (GMSA) in human nuclear matrix. The probes of the α‐satDNA bound in the GMSA with the greatest specificity, but the complex was capable of binding human satellite 3 fragment. According to ion exchange and affinity chromatography, the complex includes two DNA‐binding proteins, p70 and p80, and a non‐DNA‐binding one, p58, which enhances the specificity of binding to the α‐satDNA. GMSA, SDS‐PAGE and immunoblotting showed that the lamins, as well as constitutive centromeric proteins (CENP‐A, CENP‐B, CENP‐C, CENP‐G), were not incorporated into the complex. It was demonstrated by immunoprecipitation assay that p70 and, probably p58, share a common antigen determinant with the rod domain of intermediate filaments (IF) proteins. The results obtained indicate that the nuclear matrix contains at least one IF‐related protein that is able to bind specifically to α‐satDNA in vitro and that this protein is distinct from the lamins.
TRANSLOCATION OF P53‐REGULATED LAMININ RECEPTORS IN PRO‐APOPTOTIC MICROCIRCUMSTANCE OF HUMAN VASCULOGENESIS INHIBITION
Authors: Wang Lin , Beihua Kong , Minxing Duan , Youzhong Zhang , Shaoling Li , Chang Zengyi 
Published: September 2002

AbstractIt is not clear what type of cells will inhibit vasculogenesis and under what circumstances. Here we examined the human spontaneous abortion villi and discovered that cells in the vasculogenesis‐inhibited environment appear to be pro‐apoptotic as indicated by strong staining of bak. In particular, an increasing laminin receptor (LNR) expression in cytoplasm and on apical membrane, being most likely mediated by p53 because of coexpression, was observed in the pro‐apoptotic syncytiotrophoblasts. The transcriptional increase and translocation of the receptors to the cytoplasm and apical membrane may be used as a pathological marker, indicating a change of the structure and function of integrins in the non‐vasculogenesis micro‐environment.
EXTENDED CHROMATIN FIBRES: CRYSTALLINITY, MOLECULAR ORDER AND REACTIVITY TO CONCANAVALIN‐A
Authors: De Vidal Campos Benedicto 
Published: September 2002

AbstractThe present study was undertaken to test the reproducible formation of the extended chromatin fibres (ECF), beads and superbeads, and detect molecular order and crystallinity by optical anisotropies in those structures. Chicken erythrocyte smears and mouse liver cell imprints were treated with 2.0–3.0 m NaCl solution in 1% Triton‐X100 vertically prior to staining with 0.025% toluidine blue at pH4. Detection of birefringence and colours of abnormal dispersion of birefringence (ADB) following toluidine blue binding to DNA revealed that the DNA molecular order and crystallinity in decondensed and condensed chromatin are preserved after ECF formation. The tests for Con‐A binding to mannose/glucose residues of glycoproteins was confirmed within nuclei, and in the ECF, beads and superbeads. ECF formation was not regular. Clumped cells did not show ECF, although chromatin mobility was observed within the nuclei. Electron microscopy demonstrated that after treatment of nuclei with 0.77 m NaCl ECF always spread from the nuclei, in clumped nuclei the fibres aggregated instead of spreading.
AUTOMATED DETECTION OF MORPHOLOGICAL ALTERATIONS DURING APOPTOSIS
Authors: Lertworasirikul Thawatchai , Bunyaratvej Ahnond , Kubota Fumio 
Published: September 2002

AbstractA convenient means of measuring apoptosis is described using an automated analyzer (MF‐1; Sysmex), which normally provides rapid measurement of malarial parasites. By means of this MF‐1 procedure, apoptotic cells exhibited characteristic changes of light scatter (size) and fluorescence (DNA content) relating to cell shrinkage and nuclear fragmentation of apoptosis.
RECOMBINANT HUMAN INTERLEUKIN‐8, BUT NOT HUMAN INTERLEUKIN‐1β, INDUCES BOVINE NEUTROPHIL MIGRATION IN AN IN VITRO CO‐CULTURE SYSTEM
Authors: Lee Jaiwei , Zhao Xin 
Published: September 2002

AbstractA co‐culture system was established by culturing a bovine mammary epithelial cell line (MAC‐T) and a bovine aortic endothelial cell line on calf tail collagen pre‐coated inserts. This system allowed us to study bovine neutrophil migration across endothelium, extracellular matrix (ECM), and epithelium in the correct sequence and direction in vitro. The effect of recombinant interleukin‐1β (rHIL‐1β) and interleukin‐8 (rHIL‐8) on bovine neutrophil migration was investigated using this system. rHIL‐8 stimulated bovine neutrophil migration in a dose‐dependent fashion. The level of migrating bovine neutrophils increased up to approximately 25% when 100ng/ml of rHIL‐8 was used. On the other hand, rHIL‐1β at concentrations up to 100ng/ml did not directly induce bovine neutrophil migration. Furthermore, pre‐incubation with 5ng/ml of rHIL‐1β in the co‐culture system for 4 or 24h failed to have any effect. These results suggest that IL‐8 plays an important role in neutrophil migration into bovine mammary glands during mastitis.
INSIGHTS ON MEMBRANE FUSION
Authors: Jena Bhanu P. 
Published: September 2002

AbstractMembrane fusion is a fundamental cellular process regulating intracellular transport, neurotransmission, enzyme secretion, hormone release, and the entry/exit of viruses, to name a few. Knowledge of how opposing bilayers fuse, besides advancing our understanding of these cellular processes, will provide us with the facts to ameliorate secretory defects and prevent cellular entry or exit of pathogenic viruses. In the last few years, great strides have been made in our understanding of the molecular machinery and mechanism of membrane fusion. In this Special Issue of Cell Biology International, entitled ‘Membrane fusion: machinery and mechanism’, we have tried to cover several aspects of this vital cellular process, providing insights on the machinery, mechanism and dynamics of the process. Membrane fusion studies reported in this Special Issue have been performed on whole cells, synaptic terminals, viruses, and fusion proteins.
Late Quaternary Spatio-temporal Limnological Variations in the Altiplano of Bolivia and Peru
Authors: Wirrmann Denis , Mourguiart Philippe 
Published: September 2002

AbstractBetween the western and eastern Andean cordilleras in Peru and Bolivia, there are three main lacustrine basins: Lake Titicaca, Lake Poopó, and the group of Coipasa-Uyuni. For the past few millennia, highly variable environmental conditions have been recorded in their sediments. Today a latitudinal meteorological gradient influences the lakes' status, leading to specific deposits and ostracod communities. Lake Titicaca in the north is oligohaline, whereas Lake Poopó further south is polyhaline. In the south, the Coipasa-Uyuni depression is characterized by a 12,000-km2surficial salt crust. During the Late Pleistocene (ca. 40,000 to 25,000 yr B.P.), the water depth and salinity in paleolake Poopó fluctuated widely and paleolake Titicaca was slightly larger than at present. Sedimentation was mostly biocarbonate in the shallower areas and it was detrital-organic in the deepest zones. During the Holocene, a dry period transformed Lake Poopó into a "salar" with evaporite precipitation. Lake Titicaca registered a large decline in water level (8100-3600 yr B.P.) initially inducing gypsum precipitation followed by short influxes of water, with an ostracod faunal composition similar to that of the modern brines of Lake Poopó. Lake Titicacas' present condition only appeared between 2200 and 1500 yr B.P.
A Younger Dryas Icecap in the Equatorial Andes
Authors: Clapperton Chalmers M. , Hall Minard , Mothes Patricia , Hole Malcolm J. , Still John W. , Helmens Karin F. , Kuhry Peter , Gemmell Alastair M.D. 
Published: September 2002

AbstractMorphologic and stratigraphic evidence shows that a late-glacial ice cap existed on part of the Eastern Cordillera of Ecuador (Lat. 0° 20′ S) on ground with a mean elevation of 4200 m where none exists now. An outlet glacier from an ca. 800 km2ice cap terminated at 3850 m altitude in the Papallacta valley on the eastern side of the plateau. Radiocarbon dates show that moraines formed by this advance were ice-free by 13,20014C yr B.P. Tephras and the age of organic deposits at the plateau edge indicate ice-free conditions before 11,80014C yr B.P. This interval was followed by the expansion of an ca. 140 km2ice cap that discharged glaciers into adjacent valleys where terminal moraines were built at 3950 m altitude. AMS and conventional radiocarbon dates from macrofossils, peat, and gyttja above and below till of the readvance indicate that the ice cap formed between ca. 11,000 and 10,00014C yr B.P. and was thus coeval with the European Younger Dryas event. The ice cap developed in response to a surface temperature cooling of at least 3°C in the tropical Andes, a finding that is consistent with a coupled equatorial/high latitude North Atlantic climate system operating at the late-glacial/Holocene transition. These results are further evidence that Younger Dryas cooling may have been a global event.
H I Emission and Absorption in the Southern Galactic Plane Survey
Authors: McClure-Griffiths N. M. , Dickey John M. , Gaensler B. M. , Green A. J. , Haynes R. F. , Wieringa M. H. 
Published: September 2002

AbstractWe present preliminary results from the Southern Galactic Plane Survey (SGPS) Test Region and Parkes data. As part of the pilot project for the Southern Galactic Plane Survey, observations of a Test Region (325·5° ≤l ≤ 333·5°; −0·5° ≤ b ≤ 3·5°) were completed in December 1998. Single-dish observations of the full survey region (253° ≤ l ≤ 358 ° |b| ≤ 1°) with the Parkes Radio Telescope were completed in March 2000. We present a sample of SGPS H I data, with particular attention to the smallest-and largest-scale structures seen in absorption and emission, respectively. On the large scale, we detect many prominent H I shells. On the small scale, we note extremely compact, cold clouds seen in H I self-absorption. We explore how these two classes of objects probe opposite ends of the H I spatial power spectrum.
Frequency Dependent Ray Paths in Local Helioseismology
Authors: Barnes G. , Cally P. S. 
Published: September 2002

AbstractThe surface of the Sun is continually oscillating due to sound waves encroaching on it from the interior. Measurements of the surface velocity are used to infer some of the properties of the regions through which the sound waves have propagated. Traditionally, this has been done by using a modal decomposition of the surface disturbances. However, the use of ray descriptions, in the form of acoustic holography or time–distance helioseismology, provides an alternative approach which may reveal more detailed information about the properties of local phenomena such as sunspots and active regions. Fundamental to any such treatment is determining the correct ray paths in a given atmosphere. In the simplest approach, the ray paths are constructed to minimise the travel time between two points (Fermat's principle). However, such an approach is only valid in the high frequency limit, ω » ωc, N, where ωc is the acoustic cut-off and N the Brunt-VÄisÄlÄ frequency. Although ωc is often included in time– distance calculations, and N occasionally, the same is not true of acoustic holography. We argue that this raises concerns about image sharpness. As illustrations, representative ray paths are integrated in a realistic solar model to show that the Fermat approximation performs poorly for frequencies of helioseismic interest. We also briefly discuss the importance of the Brunt-VÄisÄlÄ frequency to the time–distance diagram.
Image Processing for the Sydney University Molonglo Sky Survey (SUMSS)
Authors: Chan B. H. P. , Cram L. E. 
Published: September 2002

AbstractThe Sydney University Molonglo Sky Survey (SUMSS) is a deep radio survey at 843 MHz, covering the region south of −30° declination. Designed to be a southern counterpart of the northern NRAO VLA Sky Survey (NVSS), SUMSS is over 40% complete, and it is now time to devise ways to generate the source catalogue for the survey. We describe here new methods to deal with image artifacts to minimise spurious fits by automatic source fitting algorithms. With the new techniques, an automatically generated, objective catalogue can be made to a 10 mJy cutoff. Catalogues can be made to a 5 mJy cutoff provided that special care is taken and certain artifacts are avoided.
Circular Polarisation in AGN
Authors: Macquart Jean-Pierre 
Published: September 2002

AbstractWe discuss the constraints that recent observations place on circular polarisation in AGN. In many sources the circular polarisation is variable on short timescales, indicating that it originates in compact regions of the sources. The best prospects for gleaning further information about circular polarisation are high resolution VLBI and scintillation ‘imaging’ which probe source structure on milliarcsecond and microarcsecond scales respectively.
Ubiquitous Column Density Variability in Seyfert 2 Galaxies
Authors: Risaliti G. , Elvis M. , Nicastro F. 
Published: September 2002

AbstractWe present a study of X-ray column density variability in Seyfert 2 galaxies. We show that variations in NH are observed in almost all the objects with multiple hard X-ray observations. Variation timescales (as short as a few months in several cases) are not in agreement with the standard scenario of a parsec-scale toroidal absorber. We propose that the X-ray absorber in Seyfert galaxies is located much nearer to the centre than previously assumed, on the broad line region scale. An extension of the model by M. Elvis (2000) can explain the observed variability. We also show preliminary results of NH variability search inside single X-ray observations, which suggest that variations can occur on timescales of a few 104 s.
Effects of Lower Boundary Conditions on the Stability of Radiative Shocks
Authors: Saxton Curtis J. 
Published: September 2002

AbstractThermal instabilities can cause a radiative shock to oscillate, thereby modulating the emission from the post-shock region. The mode frequencies are approximately quantised in analogy to those of a vibrating pipe. The stability properties depend on the cooling processes, the electron–ion energy exchange, and the boundary conditions. This paper considers the effects of the lower boundary condition on the post-shock flow, both ideally and for some specific physical models. Specific cases include constant perturbed velocity, pressure, density, flow rate, or temperature at the lower boundary, and the situation with nonzero stationary flow velocity at the lower boundary. It is found that for cases with zero terminal stationary velocity, the stability properties are insensitive to the perturbed hydrodynamic variables at the lower boundary. The luminosity responses are generally dependent on the lower boundary condition.
The Evolution of Shocks in Blazar Jets
Authors: Bicknell Geoffrey V. , Wagner Stefan J. 
Published: September 2002

AbstractWe consider the shock structures that can arise in blazar jets as a consequence of variations in the jet flow velocity. There are two possible cases: (1) a double shock system consisting of both a forward and reverse shock, and (2) a single shock (either forward or reverse) together with a rarefaction wave. These possibilities depend upon the relative velocity of the two different sections of jet. Using previously calculated spherical models for estimates of the magnetic field and electron number density of the emission region in the TeV blazar Mkn 501, we show that this region is in the form of a thin disk in the plasma rest frame. It is possible to reconcile spectral and pair opacity constraints for Mkn 501 for Doppler factors in the range of 10–20. This is easiest if the corrections for TeV absorption by the infrared background are not as large as implied by recent models.
The Carboxyl Terminus of Peptidoglycan Stem Peptides Is a Determinant for Methicillin Resistance in
Staphylococcus aureus
Authors: de Jonge Boudewijn L. M. , Gage, Douglas , Xu Naxing 
Published: September 2002

ABSTRACT

A
mecA
-containing
Staphylococcus aureus
strain was grown in the presence of high concentrations of
d
-serine,
d
-threonine, and
d
-phenylalanine. These growth conditions resulted in the replacement of the carboxyl-terminal (fifth)
d
-alanine residue of peptidoglycan stem peptides with the
d-
amino acid present in the growth medium and a reduced ability to grow in the presence of methicillin. The most dramatic effect was seen with
d
-serine. With 32 mM
d
-serine, strains that had been able to grow in the presence of 800 μg of methicillin per ml were only able to grow in the presence of less than 50 μg/ml. The results also suggest that in
S. aureus
vancomycin resistance mediated through the incorporation of precursors not terminating in
d
-alanyl-
d
-alanine would be mutually exclusive with expression of
mecA
-mediated methicillin resistance.
β-Lactamases in Ampicillin-ResistantEscherichia coliIsolates from Foods, Humans, and Healthy Animals
Authors: Briñas Laura , Zarazaga Myriam , Sáenz Yolanda , Ruiz-Larrea Fernanda , Torres Carmen 
Published: September 2002

ABSTRACTTEM-, SHV-, and OXA-type β-lactamases were studied by PCR with 124 ampicillin-resistant (AMPr)Escherichia coliisolates recovered from foods of animal origin (n= 20) and feces of humans (n= 49) and healthy animals (n= 55). PCR showed that 103 isolates were positive for TEM and negative for SHV and OXA. ThreeE. coliisolates showed a positive reaction for OXA, and one showed a positive reaction for SHV. The remaining 17E. coliisolates were negative for the three enzymes by PCR. Fifty-seven of the 103blaTEMamplicons were sequenced. Different molecular variants ofblaTEM-1were found in 52 isolates:blaTEM-1a(n= 9),blaTEM-1b(n= 36),blaTEM-1c(n= 6), andblaTEM-1f(n= 1). Four inhibitor-resistant TEM (IRT) β-lactamase-encoding genes were also detected:blaTEM-30c(IRT-2),blaTEM-34b(IRT-6),blaTEM-40b(IRT-11), andblaTEM-51a(IRT-15). A newblaTEMgene, namedblaTEM-95b, which showed a mutation in amino acid 145 (P→A) was detected. It was found in a food isolate of chicken origin (AMPr, amoxicillin-clavulanic acid susceptible). The promoter region in 24blaTEMamplicons was analyzed, and the weakP3promoter was found in 23 of them (blaTEM-1in 20 amplicons andblaTEM-51a,blaTEM-30c, andblaTEM-95bin 1 amplicon each). The strongPa/Pbpromoter was found only in theblaTEM-34bgene. No extended-spectrum β-lactamases were detected. Mutations at position −42 or −32 in theampCgene promoter were demonstrated in 4 of 10E. coliisolates for which the cefoxitin MIC was ≥16 μg/ml. Different variants ofblaTEM-1and IRTblaTEMgenes were found among the AMPrE. coliisolates from foods and the feces of humans and healthy animals, and a new gene,blaTEM-95b(P3), was detected.
Comparison of the In Vitro Activity of the Glycylcycline Tigecycline (Formerly GAR-936) with Those of Tetracycline, Minocycline, and Doxycycline against Isolates of Nontuberculous Mycobacteria
Authors: Wallace Richard J. , Brown-Elliott Barbara A. , Crist Christopher J. , Mann Linda , Wilson Rebecca W. 
Published: September 2002

ABSTRACT

We compared the in vitro activity of the glycylcycline tigecycline (formerly GAR-936) with those of tetracycline, doxycycline, and minocycline by broth microdilution against 76 isolates belonging to seven species of rapidly growing mycobacteria (RGM) and 45 isolates belonging to five species of slowly growing nontuberculous mycobacteria (NTM). By using a resistance breakpoint of >4 μg/ml for tigecycline and >8 μg/ml for tetracycline, all RGM were highly susceptible to tigecycline, with inhibition of 50% of isolates at ≤0.12 μg/ml and inhibition of 90% of isolates at 0.25 μg/ml for
Mycobacterium abscessus
and inhibition of both 50 and 90% of isolates at ≤0.12 μg/ml for
M. chelonae
and the
M. fortuitum
group. The MICs of tigecycline were the same for tetracycline-resistant and -susceptible strains, and RGM isolates were 4- to 11-fold more susceptible to tigecycline than to the tetracyclines. In contrast, no slowly growing NTM were susceptible to tigecycline, and isolates of
M. marinum
and
M. kansasii
were less susceptible to this agent than to minocycline. This new antimicrobial offers exciting therapeutic potential for the RGM, especially for isolates of the
M. chelonae
-
M. abscessus
group, against which the activities of the currently available drugs are limited.
Mutations in the
aph(2")-Ic
Gene Are Responsible for Increased Levels of Aminoglycoside Resistance
Authors: Lee Hae Kyung , Vakulenko Sergei B. , Clewell Don B. , Lerner Stephen A. , Chow Joseph W. 
Published: September 2002

ABSTRACT

Random PCR mutagenesis of the enterococcal
aph(2")-Ic
gene followed by selection for mutant enzymes that confer enhanced levels of aminoglycoside resistance resulted in mutants of APH(2")-Ic with His-258-Leu and Phe-108-Leu substitutions, all of which conferred rises in the MICs of several aminoglycosides. The mutated residues are located outside conserved regions of aminoglycoside phosphotransferases.
Penicillin-Binding Protein 1A, 2B, and 2X Alterations in Canadian Isolates of Penicillin-Resistant
Streptococcus pneumoniae
Authors: Nichol Kimberly A. , Zhanel George G. , Hoban Daryl J. 
Published: September 2002

ABSTRACT

Alterations within the penicillin-binding domain of penicillin-binding protein (PBP) genes
pbp1a
,
pbp2b
, and
pbp2x
were determined for 15 Canadian isolates of
Streptococcus pneumoniae
. All penicillin-nonsusceptible
S. pneumoniae
isolates showed a variety of PBP 2X substitutions and contained a Thr445-Ala change after the PBP 2B SSN motif. Only isolates for which penicillin MICs were ≥0.5 μg/ml had PBP 1A alterations near the STMK and SRN motifs. Sequence analysis revealed identical PBP 1A, PBP 2B, and PBP 2X substitution patterns among all isolates for which penicillin MICs were ≥1 μg/ml.