bluuebunny/crossref_metadata_2025 huggingface dataset:
A study of chromosomal aberrations in amniotic fluid cell cultures
Authors: Wolstenholme J. , Crocker M. , Jonasson J.
Published: March 2007

This paper represents the analysis of 1916 routine amniotic fluid specimens harvested by an in situ fixation technique in a prospective study with regard to cultural chromosome anomalies. Excluding constitutional abnormalities, 2·9 per cent of 19432 cells analysed showed some form of chromosome anomaly, terminal deletions (57 percent) and chromatid/chromosome breaks and gaps (18 per cent) being the most frequent, followed by interchange aberrations (13 per cent) and trisomy (5 per cent). No case was found of more than one colony from the same culture showing the same anomaly without it being present in other cultures from the same fluid. The wholly abnormal colonies had a surplus of trisomies and from the mathematical considerations presented one may infer that these are likely to reflect the presence of abnormal cells in the amniotic fluid. Partly abnormal colonies appeared at a frequency that would correspond to virtual absence of selection against chromosomally abnormal cells when cultured in vitro. The aberrations found were similar to those seen as single cell anomalies, except for chromatid breaks and exchanges. The data suggest a basic preferential induction of trisomy for chromosomes 2,18,21, and the Y‐chromosome. Structural aberrations showed a marked clustering of breakpoints around the centromeres. The frequency of mutant cells was low (1·4 × 10−3) before culture was initiated. At harvest, the frequency of abnormal cells was much higher (3 × 10−2) corresponding to 3 × 10−3 mutations per cell per generation accumulating over approximately ten generations in vitro.
Microcephaly, holoprosencephaly, hypokinesia—second report of a new syndrome
Authors: Hockey Athel , Crowhurst June , Cullity Gary
Published: March 2007

Two still‐born males whose mothers were sisters are presented. The features holoprosence‐phaly, hypokinesia, microcephaly, talipes, and other contractures correspond to those in the two male sibs reported by Morse et al, (1987). We suggest that our cases now provide evidence of an X‐linked rather than an autosomal recessive new syndrome.
Detection of rubella virus in fetal and placental tissues and in the throats of neonates after serologically confirmed rubella in pregnancy
Authors: Cradock‐Watson J. E. , Miller E. , Ridehalgh M. K. S. , Terry G. M. , Ho‐Terry L.
Published: March 2007

From 35 therapeutic abortions performed because rubella had occurred at 2–19 weeks of pregnancy, 120 fetal organs, 12 specimens of mixed products of conception, and 15 placentae were tested for rubella virus. Virus was isolated from 10 out of 11 fetuses (91 per cent) from women infected at 2–8 weeks, from 5 out of 8 (63 per cent) infected at 9–10 weeks, and from 2 out of 16 (13 per cent) infected at 11–19 weeks. Hybridization tests for viral RNA on 39 fetal organs from eight cases revealed infection in four additional fetuses. Virus was isolated from only 3 out of 15 aborted placentae, but hybridization tests on six placentae revealed infection in three additional specimens. Hybridization was superior to virus isolation for detecting rubella infection in products of conception and is therefore potentially the better method for examining chorionic villus biopsies.

Rubella virus was isolated from the throats of 4 out of 9 infants (44 per cent) infected during the first 12 weeks of gestation, but from none of 13 infected after 17 weeks. Infants in the latter group are unlikely to infect susceptible contacts.
Diaphragmatic hernia presenting in utero as a unilateral hydrothorax
Authors: Whittle M. J. , Gilmore D. H. , McNay M. B. , Turner T. L. , Raine P. A. M.
Published: March 2007

A right‐sided diaphragmatic hernia presented as a fetal hydrothorax. The fluid‐filled hernial sac enveloped the lung and presumably prevented serious compression effects. The implications of fetal thoracic anomalies are discussed.
Amniotic fluid alpha‐fetoprotein, gamma‐glutamyltranspeptidase, and autosomal trisomies
Authors: Zeitune M. , Aitken D. A. , Graham G. W. , Crossley J. A. , Ferguson‐Smith M. A.
Published: March 2007

Alpha‐fetoprotein (AFP) concentration and gamma‐glutamyltranspeptidase (GGT) activity have been analysed in amniotic fluid from a series of 65 pregnancies with autosomal trisomies. AFP values were reduced on average to 60 per cent of normal in cases of trisomy 21, but were not significantly different from normal in cases of trisomies 18 and 13. GGT activities were uniformly lower (44 per cent of normal) for all types of autosomal trisomy. A review of the literature indicates that over 85 per cent of Down's pregnancies but only 39 per cent of trisomy 18 and 13 pregnancies have amniotic fluid AFP levels below the normal median value, while the corresponding figures for GGT are 91 per cent for Down's syndrome and 96 per cent for trisomies 18 and 13.
The value of routine cervical cultures before transcervical chorionic villus sampling
Authors: Kagie M. J. , Petit P. L. Chr. , Kanhai H. H. H.
Published: March 2007

In 226 women requesting chorionic villus sampling (CVS), routine cervical cultures were obtained before the procedure. Transcervical CVS was performed irrespective of the test results. The prevalence of potential pathogens in cervical cultures at our institution is low. Beta haemolytic Streptococcus was cultured in 3 per cent of the women. No pathogenic microorganisms were isolated in 64 per cent of the women. There was no relationship between culture results and the outcome of pregnancy. These observations suggest that adequate antiseptic cleansing of the genital tract is a suitable approach and there is no need to routinely perform cultures before CVS.
An improved method of direct chromosome preparation from chorionic villus and high resolution banding technique
Authors: Xiao Sheng , Liu Quan‐Zhang , Wang Ru‐Bin , Zhang Mao‐Ying , Li Pu
Published: March 2007

The trophoblast was dissociated from the underlying mesenchymal layer either with acetic acid after short‐term prefixation or with mechanical power after fixation twice. The colcemid treatment time was shorted to 16 min and trypsin solution of low pH (6.2) was used for banding. By these steps, the quality of chromosome banding was greatly improved and complete standard chromosome diagnoses were made in 24 of 24 cases.

With the modified technique, high resolution banding chromosomes were consistently obtained after short‐term incubation.
Seven cases of trisomy 3 mosaicism in chorionic villi
Authors: Guerneri S. , Fortuna R. , Romitti L. , Bettio D. , Simoni G.
Published: March 2007

This paper describes seven cases of confined chorionic mosaicism with trisomy 3. The chromosomally abnormal cell line in chorionic villi was revealed in three cases at diagnostic CVS and in four cases at the evacuation of the uterine cavity after a missed abortion had been diagnosed by ultrasound. In two of these cases, the abortion occurred after apparently normal development of the fetus during the second trimester of pregnancy. An evaluation of the effect of confined chorionic mosaicism with trisomy 3 on the viability of the conceptus has been attempted.
Community attitudes to cystic fibrosis carrier testing in England: A pilot study
Authors: Williamson R. , Allison M. E. D. , Bentley T. J. , Lim S. M. C. , Watson E. , Chapple J. , Adam S. , Boulton M.
Published: March 2007

Inexpensive and accurate carrier testing for cystic fibrosis (CF) will be possible in the near future. There are no existing studies on the attitudes of English persons in the community to carrier testing for CF or any other recessive disorder. We have conducted a trial study of 166 persons at two schools, two doctors' surgeries, and a family planning clinic. Only a minority had clear pre‐existing knowledge of cystic fibrosis and its genetic nature. However, over 80 per cent of those questioned expressed interest in knowing their carrier status. Although it is well known that uptake can only be assessed when a service is in place, and while further studies are required to confirm that testing will be of interest to couples of reproductive age with no previous knowledge of CF, the data strongly suggest that there will be interest in communitywide testing for CF carrier status when such a test becomes available in the United Kingdom.
Prenatal diagnosis of a case of tetrasomy 9p
Authors: McDowall A. A. , Blunt S. , Berry A. C. , Fensom A. H.
Published: March 2007

A male fetus with tetrasomy 9p [47,XY, + i(9p)] is presented. The cytogenetic interpretation of the marker chromosome was confirmed by assessing the activity of the enzyme galactose I‐phosphate uridyl transferase. The clinical findings of the case show features in common with previously reported cases.
Exclusion of chromosomal mosaicism in amniotic fluid cultures: Efficacy of in situ versus flask techniques
Authors: Cheung Sau W. , Spitznagel Edward , Featherstone Terry , Crane James P.
Published: March 2007

Accurate diagnosis of mosaicism in amniotic fluid cell cultures represents a major problem. If insufficient cells are analysed, true fetal mosaicism may go undetected. False‐positive diagnosis is also possible since a second cell line may arise in vitro and not reflect the true fetal genetic constitution. These difficulties apply to both flask and in situ culture techniques, to varying degrees. The relative accuracy of flask versus in situ culture techniques in excluding mosaicism was determined by statistical analysis of experimental data from ten pairs of mixed male‐female amniotic fluid specimens. The data support the idea that the majority of in situ colonies are independent of one another. The following conclusions are drawn: (1) analysis of a single metaphase from a number of different colonies enhances the confidence for excluding mosaicism; (2) analysis of more than one cell per colony offers little advantage; (3) exclusion of a given level of mosaicism requires analysis of fewer metaphases using the in situ method; (4) the confidence for excluding mosaicism is high with both in situ and flask techniques, using the provided guidelines; and (5) it is shown that the two‐stage approach used by many laboratories is currently the most efficient way to exclude mosaicism.
Umbilical cord haematoma as a complication of intrauterine intravascular blood transfusion
Authors: Keckstein Georg , Tschurtz Sonja , Schneider Volker , Mütter Wolfgang , Terinde Rainer , Jonatha Wolf‐Dietrich
Published: March 2007

Between October 1985 and February 1989, 49 ultrasound‐guided intravascular fetal blood transfusions were performed in 16 patients (14 with rhesus (Rh) isoimmunization, 2 with non‐immunologic hydrops fetalis (NIHF)).

As an intra‐operative complication, perivascular haematoma of the cord occurred in three patients (7 per cent). In two cases, fetal bradycardia necessitated delivery by Caesarean section at 30 and 32 weeks' gestation, respectively. In the third case, fetal bradycardia developed during transfusion, at 31 weeks' gestation, but normalized within 3 min. The baby was delivered as planned at 36 weeks of gestation, after another transfusion at 34 weeks. Dislodgement of the needle tip into perivascular tissue, caused by sudden fetal or maternal movements, is the reason for this complication. The haematoma develops as a result of delayed recognition and continuous transfusion into Wharton' s jelly. Cord haematoma may be diagnosed in time by continuous ultrasound imaging, as illustrated in case 3.

To minimize the risk of needle dislodgement during transfusion, sedation of the mother and complete immobilization of the fetus by injecting a short‐acting muscle relaxant into the umbilical vessel are recommended.
Prenatal diagnosis of autosomal dominant microcephaly and postnatal evaluation with magnetic resonance imaging
Authors: Persutte Wayne H. , Kurczynski Thaddeus W. , Chaudhuri K. , Lenke Roger R. , Woldenberg Lee , Brinker Ray A.
Published: March 2007

A case of fetal autosomal dominant microcephaly was prenatally diagnosed with ultrasonography in a woman with previously undiagnosed microcephaly. At the time of initial ultrasonographic assessment, the mother was identified to have a markedly small cranium, consistent with maternal microcephaly. The ultrasonographic examination showed the fetal head size to be four standard deviations below the mean for gestational age. Gesta‐tional dating from the other biometric parameters and from the last menstrual period was consistent with 31 weeks' gestation. Neurosonographic evaluation of the fetus revealed no obvious structural abnormalities. Serial ultrasonographic examinations at 35 and 38 weeks' gestation showed no changes in the fetal head size. A 2·64 kg male fetus was delivered at term. Neonatal assessment showed the fetal head circumference to be less than the second percentile for gestational age. Neurologic assessment of the neonate with magnetic resonance imaging showed abnormal development of the brain, with small cerebellar and cerebral hemispheres, and pachygyria. These images are compared with the magnetic resonance images of the mother. Our findings of maternal and fetal microcephaly are consistent with autosomal dominant microcephaly. To our knowledge, this is the first report of the prenatal diagnosis of autosomal dominant microcephaly.
Oligohydramnios sequence in a live‐born infant following chorionic villus sampling
Authors: Turnpenny P. D. , Hakim M. M. , Thwaites R. J. , Nash R. M. , Allen H. E. , Zacharian Y. , Chazantchuk T. , Weiner E.
Published: March 2007

We describe an infant born at 29 weeks' gestation with oligohydramnios sequence due to amniotic fluid leakage following chorionic villus sampling at 12 weeks. To our knowledge, this is the first such report.
Discriminant analysis for assessing the value of amniotic fluid microvillar enzymes in the prenatal diagnosis of cystic fibrosis
Authors: Szabó Mária , Münnich Ákos , Teichmann Farkas , Huszka Mariann , Veress Lajos , Papp Zoltán
Published: March 2007

We have analysed the sensitivity, specificity, and reliability of biochemical diagnosis based on microvillar membrane enzyme assay and using discriminant analysis in amniotic fluid samples obtained from 54 pregnancies at high risk for cystic fibrosis and 125 normal pregnancies. Our results show that amniotic fluid trehalase, alkaline phosphatase, alkaline phosphatase isoenzymes and gamma‐glutamyltransferase enzyme activities measured during 16–20 gestational weeks, in spite of their non‐specificity for cystic fibrosis, have a very good predictive value for fetal cystic fibrosis or exclude the possibility of the disease. Overall enzyme activity analysis provided over 90 per cent reliability of the method.
Metabolism controls dimerization of the chloroplast FoF1 ATP synthase in Chlamydomonas reinhardtii
Authors: Schwaßmann Helena J. , Rexroth Sascha , Seelert Holger , Dencher Norbert A.
Published: March 2007

As compared to photoautotrophic growth, an increased assembly of ATP synthase dimers on the expense of preexisting monomers during photomixotrophic growth was observed, demonstrating a metabolic control of the dimerization process.
Comparison of N‐Linked Oligosaccharides of Recombinant Human Tissue Kallikrein Produced by Chinese Hamster Ovary Cells on Microcarrier Beads and in Serum‐Free Suspension Culture
Authors: Watson Eric , Shah Bhavana , Leiderman Lisa , Hsu Yueh‐Rong , Karkare Subhash , Lu Hsieng S. , Lin Fu‐Kuen
Published: March 2007

Glycosylation heterogeneity in recombinant human tissue kallikrein (r‐HuTK) produced by Chinese hamster ovary (CHO) cells from microcarrier culture and from a serum‐free suspension cell recycle process has been compared. Significant differences in the degree of sialylation were observed in glycoform distribution and oligosaccharide heterogeneity. High‐performance liquid chromatography with a pellicular anion‐exchange column under low pH eluant conditions was used to characterize the number and types of N‐linked complex type oligosaccharides present. The oligosaccharides were released by N‐gly‐canase and, after reduction, were resolved into a number of peaks containing one, two, three, and four sialic acids with an additional subfractionation based on the nature of the antennary structure. The microcarrier process resulted in a reduced amount of sialylated oligosaccharide species as compared to the suspension cell process. Removal of sialic acid followed by chromatography of the asialooligosaccharides under high pH anion‐exchange conditions indicated that the same antennary structures were present but in slightly different relative amounts. The oligosaccharide profiles are indicative of a highly complex array of microheterogeneity present, encompassing mono‐, di‐, tri‐, and tetrasialylated complex type oligosaccharides.
Calcium Signaling in Individual BC3H1 Cells: Speed of Calcium Mobilization and Heterogeneity
Authors: Mahama Patricia A. , Linderman Jennifer J.
Published: March 2007

Receptor/ligand binding on a cell surface may activate the calcium signal transduction cascade, resulting in the release of calcium from intracellular stores into the cytosol. Changes in intracellular free calcium, [Ca2+]i, following ligand stimulation have been linked to a variety of cell responses, from muscle contraction to hormone secretion. We have monitored changes in [Ca2+]iin single smooth muscle‐like BC3H1 cells following stimulation by the vasoconstrictor phenylephrine, using the fluorescent calcium probe, fura‐2, in a digital fluorescence imaging system. We find that not all cells respond to ligand stimulation with changes in [Ca2+]i. In addition, cells which respond to ligand stimulation exhibit considerable heterogeneity in the speed of calcium mobilization for a given ligand concentration. Both the population‐averaged speed for calcium mobilization and the fraction of cells which respond to ligand stimulation are increasing functions of the ligand concentration. In contrast, the magnitude of the ligand‐stimulated increase in [Ca2+]ifrom basal to peak levels in responding cells is independent of ligand concentration. We postulate that the heterogeneity seen in the ligand‐induced mobilization of calcium among single cells is a function of distinct differences between cells, such as number of receptors, size of the intracellular calcium store, or phospholipase C activity. We have developed a mathematical model, based on the calcium signal transduction cascade, to predict single‐cell calcium responses to ligand stimulation. We have systematically incorporated cell‐to‐cell parameter heterogeneity into the model by randomly selecting single‐cell parameter values from a Gaussian distribution. Model simulations predict both single‐cell and population‐averaged trends that we have observed experimentally. The results of this work suggest that increases in a population response may be the result of increased participation in the response as opposed to increases in the magnitudes of individual cell responses.
Estimation of Temperature‐Dependent Pore Size in Poly(N‐isopropylacrylamide) Hydrogel Beads
Authors: Park Tae Gwan , Hoffman Allan S.
Published: March 2007

The pore sizes of various temperature‐sensitive hydrogel beads have been estimated at different temperatures by a gel filtration method using several probe molecules of known molecular weight. The hydrogel beads were prepared by inverse suspension copoly‐merizations of a series of N‐isopropylacrylamide (NIPAAm) and acrylamide (AAm) monomers with a small amount of cross‐linker. These hydrogel beads exhibit LCST (lower critical solution temperature) behavior in aqueous solution, that is, expanding and swelling when cooled below the LCST and shrinking and collapsing when heated above the LCST. The pore sizes of these temperature‐sensitive hydrogel beads are affected significantly by both the temperature and the gel composition, but not much by cross‐linker concentration.
Motion of Model Leukocytes near a Wall in Simple Shear Flow
Authors: Tempelman Linda A. , Park Samuel , Hammer Daniel A.
Published: March 2007

Receptor‐mediated cell adhesion to surfaces depends on the motion of the cell prior to adhesion. We studied the hydrodynamic behavior of cells near a wall in simple shear flow using a model leukocyte system that we have also used extensively in cell—substrate adhesion studies. Specifically, we measured the velocity of rat basophilic leukemia (RBL) cells near a surface in a parallel‐plate flow chamber and compared it to the motion of polystyrene beads and glutaraldehyde‐fixed RBL cells. We found that RBL cells (13 μm diameter) travel 25% faster than polystyrene beads of 14.5 μm diameter for a wide range of shear rates (20–180 s−1); this suggests that RBL cells would travel 39% faster than polystyrene beads of equivalent size. Glutaraldehyde‐fixed RBL cells travel at a velocity between those of live cells and 14.5‐μm beads. These differences in velocities have been observed over both polyacrylamide gel and glass substrates. Application of a theory for hard sphere motion near a wall in simple shear flow at low Reynolds number [Goldman, A. J.; Cox, R. G.; Brenner, H. Chem. Eng. Sci. 1967b, 22, 653–660] to our measured cell velocities suggests that cells are separated from the wall by ≥550 nm. Such large separation distances have also been predicted by others who have used hard sphere theory to analyze the effect of shear flow on cell motion near walls. However, the extensive receptor‐mediated cell adhesion seen in these systems is inconsistent with these separation distances, which are ∼30 times greater than the distance required for receptor—ligand contact. Instead, we propose that, because of cell deformability and cell surface roughness, cells remain within a separation distance that allows for molecular contact while they travel faster than the hard sphere theory predicts. Therefore, the theory of Goldman and co‐workers, while adequate for hard sphere motion, is likely not accurate for cellular motion.
An investigation of the sensitivity of the clear‐sky outgoing longwave radiation to atmospheric temperature and water vapor
Authors: Huang Yi , Ramaswamy V. , Soden Brian
Published: March 2007

The rate at which the outgoing longwave radiation (OLR) responds to perturbations in temperature and moisture plays a fundamental role in determining climate sensitivity. This study examines the clear‐sky OLR sensitivities to temperature and water vapor, as quantified by its partial derivatives (radiative Jacobians). The Jacobians, as computed by the Geophysical Fluid Dynamics Laboratory (GFDL)'s line‐by‐line (LBL) radiative transfer model are used to verify the results from the parameterized GFDL GCM (general circulation model) radiation code. The results show that the (1) Jacobians of OLR due to incremental changes in temperature and water vapor are insensitive to different formulations of water vapor continuum absorption and (2) Jacobians of OLR are properly captured by the GCM longwave band approximation. Simulations with the GCM demonstrate that uncertainties in the formulation of continuum absorption have little impact on the climate model simulation of clear‐sky OLR changes in response to prescribed sea surface temperature (SST) perturbation. The numerically computed Jacobians of OLR are used to reconstruct the tropical annual mean OLR from the variations of temperature and water vapor over the period 1980–1999. The reconstructed OLR anomaly time series agrees well with that computed explicitly by the GCM. On the basis of this result, it becomes possible to separate out the temperature and water vapor contributions to the OLR variation. The results show that the temperature contribution dominates the water vapor contribution in the lower and middle troposphere, while in the upper troposphere the two contributions largely offset each other.
Formation and variation of temperature inversions in the eastern subarctic North Pacific
Authors: Ueno Hiromichi , Oka Eitarou , Suga Toshio , Onishi Hiroji , Roemmich Dean
Published: March 2007

Hydrographic data from profiling float observations for 2001–2005 and from expendable bathythermograph observations for 1993–2005 were analyzed to study the formation and variation of temperature inversions (T‐inversions) in the eastern subarctic North Pacific (SNP). The formation and variation of T‐inversions differed significantly between the northern and southern regions of the eastern SNP. In the northern region, the temperature minimum (T‐min) at the top of T‐inversions outcropped to the sea surface and was cooled in the mixed layer nearly every winter. This process caused a seasonal cycle in the magnitude of T‐inversions (ΔT), with a maximum in winter. In the southern region, the winter T‐min outcropped relatively infrequently and the ΔT did not exhibit a significant maximum in winter during most years. The T‐min in the southern region was likely to outcrop upstream near the date line roughly one year earlier and was then advected to the southern region.
Seismic anisotropy reveals focused mantle flow around the Calabrian slab (Southern Italy)
Authors: Baccheschi P. , Margheriti L. , Steckler M. S.
Published: March 2007

SKS splitting at the Calabrian subduction zone, with delay times (δt) up to 3s, reveals the presence of a strong anisotropic fabric. Fast directions (ϕ) are oriented NNE‐SSW in the Calabrian Arc (C.A.) and rotate NNW‐SSE to the north following the arcuate shape of the subducting plate. We interpret the trench‐parallel ϕ as local‐scale mantle flow driven by the retrograde motion of the slab; the absence of trench perpendicular ϕ below the Southern Apennines (S.A.) excludes the presence of a seismically detectable return flow at its NE edge. This may be due to the relative youth and limited width of the S.A. slab tear. A possible return flow is identified farther north at the boundary of the S.A. and Central Apennines. Different and weaker anisotropy is present below the Apulian Platform (A.P.). This implies that the influence of the slab rollback in the sub‐slab mantle is limited to less then 100 km from the slab.
Why are there large differences between models in global budgets of tropospheric ozone?
Authors: Wu Shiliang , Mickley Loretta J. , Jacob Daniel J. , Logan Jennifer A. , Yantosca Robert M. , Rind David
Published: March 2007

Global 3‐D tropospheric chemistry models in the literature show large differences in global budget terms for tropospheric ozone. The ozone production rate in the troposphere, P(Ox), varies from 2300 to 5300 Tg yr−1 across models describing the present‐day atmosphere. The ensemble mean of P(Ox) in models from the post‐2000 literature is 35% higher than that compiled in the Intergovernmental Panel on Climate Change (IPCC) Third Assessment Report (TAR). Simulations conducted with the GEOS‐Chem model using two different assimilated meteorological data sets for 2001 (GEOS‐3 and GEOS‐4), as well as 3 years of GISS GCM meteorology, show P(Ox) values in the range 4250–4700 Tg yr−1; the differences appear mostly because of clouds. Examination of the evolution of P(Ox) over the GEOS‐Chem model history shows major effects from changes in heterogeneous chemistry, the lightning NOx source, and the yield of organic nitrates from isoprene oxidation. Multivariate statistical analysis of model budgets in the literature indicates that 74% of the variance in P(Ox) across models can be explained by differences in NOx emissions, inclusion of nonmethane volatile organic compounds (NMVOCs, mostly biogenic isoprene), and ozone influx from stratosphere‐troposphere exchange (STE). Higher NOx emissions, more widespread inclusion of NMVOC chemistry, and weaker STE in the more recent models increase ozone production; however, the effect of NMVOCs does not appear generally sensitive to the magnitude of emissions within the range typically used in models (500–900 Tg C yr−1). We find in GEOS‐Chem that P(Ox) saturates when NMVOC emissions exceed 200 Tg C yr−1 because of formation of organic nitrates from isoprene oxidation, providing an important sink for NOx.
Dynamic Couplings, Radiative and Nonradiative Lifetimes of the A1Σ+ and C1Σ+ States of the KH Molecule
Authors: Khelifi Neji , Oujia Brahim , Gadea Florent Xavier
Published: March 2007

In this article, dynamic couplings for X-A, X-C, and A-C, by using first and second derivatives terms neglected in the Born–Oppenheimer approximation, are calculated. Newly calculated radiative transition probabilities for the A1Σ+→X1Σ+ and C1Σ+→X1Σ+ emission bands of KH are used to calculate the radiative and nonradiative lifetimes of the various vibrational levels (0⩽v⩽35) and (0⩽v⩽55) of A1Σ+ and C1Σ+ states of the diatomic potassium hydride, KH, molecule. For higher vibrational levels, an estimate of the bound-to-free emission probability is also needed and included. Accurate positions, radiative and nonradiative lifetimes of states belonging to the adiabatic A and C states of the KH molecule are estimated. The results come from a Fermi’s Golden Rule treatment in coupling calculation. That confirms the accuracy reached in both approaches and also in the treatment of the diabatic-adiabatic transformation. It involves, in particular, an effective phase choice that is needed to properly estimate nonadiabatic couplings.
Prediction of Enthalpy of Formation in the Solid State (at 298.15K) Using Second-Order Group Contributions—Part 2: Carbon-Hydrogen, Carbon-Hydrogen-Oxygen, and Carbon-Hydrogen-Nitrogen-Oxygen Compounds
Authors: Salmon Anna , Dalmazzone Didier
Published: March 2007

A program has been undertaken to develop a new group contribution method, based on Benson’s group additivity technique, estimate as precisely as possible solid state enthalpies of formation, at 298.15K, of C–H compounds, C–H–O compounds, and C–H–N–O compounds. A set of 1017 experimental values of the enthalpy of formation has been studied and compared to the predicted values of this new method as well as the method of Domalski and Hearing. This new estimation technique leads to a higher precision and reliability. With the inclusion of additional group values, a wider range of compounds can be studied (compared to the Domalski and Hearing technique). Comparison with a quantum mechanical method [Rice et al., Combust. Flame 118, 445 (1999)] shows that the list of group contribution values, ring strain corrections, and non-nearest neighbor interactions provided here yields better estimates overall.
Loss of muscle-specific RING-finger 3 predisposes the heart to cardiac rupture after myocardial infarction
Authors: Fielitz Jens , van Rooij Eva , Spencer Jeffrey A. , Shelton John M. , Latif Shuaib , van der Nagel Roel , Bezprozvannaya Svetlana , de Windt Leon , Richardson James A. , Bassel-Duby Rhonda , Olson Eric N.
Published: March 2007

RING-finger proteins commonly function as ubiquitin ligases that mediate protein degradation by the ubiquitin-proteasome pathway. Muscle-specific RING-finger (MuRF) proteins are striated muscle-restricted components of the sarcomere that are thought to possess ubiquitin ligase activity. We show that mice lacking MuRF3 display normal cardiac function but are prone to cardiac rupture after acute myocardial infarction. Cardiac rupture is preceded by left ventricular dilation and a severe decrease in cardiac contractility accompanied by myocyte degeneration. Yeast two-hybrid assays revealed four-and-a-half LIM domain (FHL2) and γ-filamin proteins as MuRF3 interaction partners, and biochemical analyses showed these proteins to be targets for degradation by MuRF3. Accordingly, FHL2 and γ-filamin accumulated to abnormal levels in the hearts of mice lacking MuRF3. These findings reveal an important role of MuRF3 in maintaining cardiac integrity and function after acute myocardial infarction and suggest that turnover of FHL2 and γ-filamin contributes to this cardioprotective function of MuRF3.
A temporal-specific and transient cAMP increase characterizes odorant classical conditioning
Authors: Cui Wen , Smith Andrew , Darby-King Andrea , Harley Carolyn W. , McLean John H.
Published: March 2007

Increases in cyclic adenosine monophosphate (cAMP) are proposed to initiate learning in a wide variety of species. Here, we measure changes in cAMP in the olfactory bulb prior to, during, and following a classically conditioned odor preference trial in rat pups. Measurements were taken up to the point of maximal CREB phosphorylation in olfactory bulb mitral cells. Using both drug and natural unconditioned stimuli we found effective learning was associated with an increase in cAMP at the end of the conditioning trial, followed by a decrease 5 min later. This early timing of a transient cAMP increase occurred only when the odor was paired with an effective drug or natural unconditioned stimulus (US). The data support the hypothesis that the rate of adenylate cyclase activation is enhanced by pairing calcium and G-protein activation and that the timing of transient cAMP signaling is critical to the initiation of classical conditioning.
Characterization of Lipid Rafts from Medicago truncatula Root Plasma Membranes: A Proteomic Study Reveals the Presence of a Raft-Associated Redox System
Authors: Lefebvre Benoit , Furt Fabienne , Hartmann Marie-Andrée , Michaelson Louise V. , Carde Jean-Pierre , Sargueil-Boiron Françoise , Rossignol Michel , Napier Johnathan A. , Cullimore Julie , Bessoule Jean-Jacques , Mongrand Sébastien
Published: March 2007

Several studies have provided new insights into the role of sphingolipid/sterol-rich domains so-called lipid rafts of the plasma membrane (PM) from mammalian cells, and more recently from leaves, cell cultures, and seedlings of higher plants. Here we show that lipid raft domains, defined as Triton X-100-insoluble membranes, can also be prepared from Medicago truncatula root PMs. These domains have been extensively characterized by ultrastructural studies as well as by analysis of their content in lipids and proteins. M. truncatula lipid domains are shown to be enriched in sphingolipids and Δ7-sterols, with spinasterol as the major compound, but also in steryl glycosides and acyl-steryl glycosides. A large number of proteins (i.e. 270) have been identified. Among them, receptor kinases and proteins related to signaling, cellular trafficking, and cell wall functioning were well represented whereas those involved in transport and metabolism were poorly represented. Evidence is also given for the presence of a complete PM redox system in the lipid rafts.
Exploring Effective Methods for Simulating Damaged Structures With Geometric Variation: Toward Intelligent Failure Detection
Authors: McAdams Daniel A. , Comella David , Tumer Irem Y.
Published: March 2007

Inaccuracies in the modeling assumptions about the distributional characteristics of the monitored signatures have been shown to cause frequent false positives in vehicle monitoring systems for high-risk aerospace applications. To enable the development of robust fault detection methods, this work explores the deterministic as well as variational characteristics of failure signatures. Specifically, we explore the combined impact of crack damage and manufacturing variation on the vibrational characteristics of beams. The transverse vibration and associated eigenfrequencies of the beams are considered. Two different approaches are used to model beam vibrations with and without crack damage. The first approach uses a finite difference approach to enable the inclusion of both cracks and manufacturing variation. The crack model used with both approaches is based on a localized decrease in the Young’s modulus. The second approach uses Myklestad’s method to evaluate the effects of cracks and manufacturing variation. Using both beam models, Monte Carlo simulations are used to explore the impacts of manufacturing variation on damaged and undamaged beams. Derivations are presented for both models. Conclusions are presented on the choice of modeling techniques to define crack damage, and its impact on the monitored signal, followed by conclusions about the distributional characteristics of the monitored signatures when exposed to random manufacturing variations.
New Method for Evaluation of Genotoxicity, Based on the Use of Real-Time PCR and Lysogenic Gram-Positive and Gram-Negative Bacteria
Authors: Soberón Nora , Martín Rebeca , Suárez Juan E.
Published: March 2007

A method for the detection of the SOS response as measured by the liberation of resident prophages from the genomes of their hosts is described. It is based on the use of two converging oligonucleotides that flank the
attP
attachment site of the phage as primers for real-time PCR. Amplification was observed only after the phage DNA became excised. The system responds to both chemicals and physical conditions. Quantitative data on the concentration and/or potency of the genotoxic condition were obtained. Results can be achieved within 1 day and are less susceptible to possible toxic effects than phage generation or other methods that require DNA synthesis. The use of both gram-positive and gram-negative bacteria widens the range of compounds that can be tested because it eliminates impermeability problems derived from the particular composition of each cell wall type.
Alignment-Independent Comparisons of Human Gastrointestinal Tract Microbial Communities in a Multidimensional 16S rRNA Gene Evolutionary Space
Authors: Rudi Knut , Zimonja Monika , Kvenshagen Bente , Rugtveit Jarle , Midtvedt Tore , Eggesbø Merete
Published: March 2007

We present a novel approach for comparing 16S rRNA gene clone libraries that is independent of both DNA sequence alignment and definition of bacterial phylogroups. These steps are the major bottlenecks in current microbial comparative analyses. We used direct comparisons of taxon density distributions in an absolute evolutionary coordinate space. The coordinate space was generated by using alignment-independent bilinear multivariate modeling. Statistical analyses for clone library comparisons were based on multivariate analysis of variance, partial least-squares regression, and permutations. Clone libraries from both adult and infant gastrointestinal tract microbial communities were used as biological models. We reanalyzed a library consisting of 11,831 clones covering complete colons from three healthy adults in addition to a smaller 390-clone library from infant feces. We show that it is possible to extract detailed information about microbial community structures using our alignment-independent method. Our density distribution analysis is also very efficient with respect to computer operation time, meeting the future requirements of large-scale screenings to understand the diversity and dynamics of microbial communities.
Role of Cystathionine β-Lyase in Catabolism of Amino Acids to Sulfur Volatiles by Genetic Variants of
Lactobacillus helveticus
CNRZ 32
Authors: Lee Won-Jae , Banavara Dattatreya S. , Hughes Joanne E. , Christiansen Jason K. , Steele James L. , Broadbent Jeffery R. , Rankin Scott A.
Published: March 2007

Catabolism of sulfur-containing amino acids plays an important role in the development of cheese flavor. During ripening, cystathionine β-lyase (CBL) is believed to contribute to the formation of volatile sulfur compounds (VSCs) such as methanethiol and dimethyl disulfide. However, the role of CBL in the generation of VSCs from the catabolism of specific sulfur-containing amino acids is not well characterized. The objective of this study was to investigate the role of CBL in VSC formation by
Lactobacillus helveticus
CNRZ 32 using genetic variants of
L. helveticus
CNRZ 32 including the CBL-null mutant, complementation of the CBL-null mutant, and the CBL overexpression mutant. The formation of VSCs from methionine, cystathionine, and cysteine was determined in a model system using gas chromatography-mass spectrometry with solid-phase microextraction. With methionine as a substrate, CBL overexpression resulted in higher VSC production than that of wild-type
L. helveticus
CNRZ 32 or the CBL-null mutant. However, there were no differences in VSC production between the wild type and the CBL-null mutant. With cystathionine, methanethiol production was detected from the CBL overexpression variant and complementation of the CBL-null mutant, implying that CBL may be involved in the conversion of cystathionine to methanethiol. With cysteine, no differences in VSC formation were observed between the wild type and genetic variants, indicating that CBL does not contribute to the conversion of cysteine.
Biofilm Cohesiveness Measurement Using a Novel Atomic Force Microscopy Methodology
Authors: Ahimou Francois , Semmens Michael J. , Novak Paige J. , Haugstad Greg
Published: March 2007

Biofilms can be undesirable, as in those covering medical implants, and beneficial, such as when they are used for waste treatment. Because cohesive strength is a primary factor affecting the balance between growth and detachment, its quantification is essential in understanding, predicting, and modeling biofilm development. In this study, we developed a novel atomic force microscopy (AFM) method for reproducibly measuring, in situ, the cohesive energy levels of moist 1-day biofilms. The biofilm was grown from an undefined mixed culture taken from activated sludge. The volume of biofilm displaced and the corresponding frictional energy dissipated were determined as a function of biofilm depth, resulting in the calculation of the cohesive energy. Our results showed that cohesive energy increased with biofilm depth, from 0.10 ± 0.07 nJ/μm
3
to 2.05 ± 0.62 nJ/μm
3
. This observation was reproducible, with four different biofilms showing the same behavior. Cohesive energy also increased from 0.10 ± 0.07 nJ/μm
3
to 1.98 ± 0.34 nJ/μm
3
when calcium (10 mM) was added to the reactor during biofilm cultivation. These results agree with previous reports on calcium increasing the cohesiveness of biofilms. This AFM-based technique can be performed with available off-the-shelf instrumentation. It could therefore be widely used to examine biofilm cohesion under a variety of conditions.
Influence of Vitamin B
12
and Cocultures on the Growth of
Dehalococcoides
Isolates in Defined Medium
Authors: He Jianzhong , Holmes Victor F. , Lee Patrick K. H. , Alvarez-Cohen Lisa
Published: March 2007

Bacteria belonging to the genus
Dehalococcoides
play a key role in the complete detoxification of chloroethenes as these organisms are the only microbes known to be capable of dechlorination beyond dichloroethenes to vinyl chloride (VC) and ethene. However,
Dehalococcoides
strains usually grow slowly with a doubling time of 1 to 2 days and have complex nutritional requirements. Here we describe the growth of
Dehalococcoides ethenogenes
195 in a defined mineral salts medium, improved growth of strain 195 when the medium was amended with high concentrations of vitamin B
12
, and a strategy for maintaining
Dehalococcoides
strains on lactate by growing them in consortia. Although strain 195 could grow in defined medium spiked with ∼0.5 mM trichloroethene (TCE) and 0.001 mg/liter vitamin B
12
, the TCE dechlorination and cellular growth rates doubled when the vitamin B
12
concentration was increased 25-fold to 0.025 mg/liter. In addition, the final ratios of ethene to VC increased when the higher vitamin concentration was used, which reflected the key role that cobalamin plays in dechlorination reactions. No further improvement in dechlorination or growth was observed when the vitamin B
12
concentration was increased to more than 0.025 mg/liter. In defined consortia containing strain 195 along with
Desulfovibrio desulfuricans
and/or
Acetobacterium woodii
and containing lactate as the electron donor, tetrachloroethene (∼0.4 mM) was completely dechlorinated to VC and ethene and there was concomitant growth of
Dehalococcoides
cells. In the cultures that also contained
D. desulfuricans
and/or
A. woodii
, strain 195 cells grew to densities that were 1.5 times greater than the densities obtained when the isolate was grown alone. The ratio of ethene to VC was highest in the presence of
A. woodii
, an organism that generates cobalamin de novo during metabolism. These findings demonstrate that the growth of
D. ethenogenes
strain 195 in defined medium can be optimized by providing high concentrations of vitamin B
12
and that this strain can be grown to higher densities in cocultures with fermenters that convert lactate to generate the required hydrogen and acetate and that may enhance the availability of vitamin B
12
.
Biogeography of Actinomycete Communities and Type II Polyketide Synthase Genes in Soils Collected in New Jersey and Central Asia
Authors: Wawrik Boris , Kutliev Djumaniyaz , Abdivasievna Urinova A. , Kukor Jerome J. , Zylstra Gerben J. , Kerkhof Lee
Published: March 2007

Soil microbial communities are believed to be comprised of thousands of different bacterial species. One prevailing idea is that “everything is everywhere, and the environment selects,” implying that all types of bacteria are present in all environments where their growth requirements are met. We tested this hypothesis using actinomycete communities and type II polyketide synthase (PKS) genes found in soils collected from New Jersey and Uzbekistan (
n
= 91). Terminal restriction fragment length polymorphism analysis using actinomycete 16S rRNA and type II PKS genes was employed to determine community profiles. The terminal fragment frequencies in soil samples had a lognormal distribution, indicating that the majority of actinomycete phylotypes and PKS pathways are present infrequently in the environment. Less than 1% of peaks were detected in more than 50% of samples, and as many as 18% of the fragments were unique and detected in only one sample. Actinomycete 16S rRNA fingerprints clustered by country of origin, indicating that unique populations are present in North America and Central Asia. Sequence analysis of type II PKS gene fragments cloned from Uzbek soil revealed 35 novel sequence clades whose levels of identity to genes in the GenBank database ranged from 68 to 92%. The data indicate that actinomycetes are patchily distributed but that distinct populations are present in North American and Central Asia. These results have implications for microbial bioprospecting and indicate that the cosmopolitan actinomycete species and PKS pathways may account for only a small proportion of the total diversity in soil.
Role of Lipid Composition and Lipid Peroxidation in the Sensitivity of Fungal Plant Pathogens to Aluminum Chloride and Sodium Metabisulfite
Authors: Avis Tyler J. , Michaud Mélanie , Tweddell Russell J.
Published: March 2007

Aluminum chloride and sodium metabisulfite have shown high efficacy at low doses in controlling postharvest pathogens on potato tubers. Direct effects of these two salts included the loss of cell membrane integrity in exposed pathogens. In this work, four fungal potato pathogens were studied in order to elucidate the role of membrane lipids and lipid peroxidation in the relative sensitivity of microorganisms exposed to these salts. Inhibition of mycelial growth in these fungi varied considerably and revealed sensitivity groups within the tested fungi. Analysis of fatty acids in these fungi demonstrated that sensitivity was related to high intrinsic fatty acid unsaturation. When exposed to the antifungal salts, sensitive fungi demonstrated a loss of fatty acid unsaturation, which was accompanied by an elevation in malondialdehyde content (a biochemical marker of lipid peroxidation). Our data suggest that aluminum chloride and sodium metabisulfite could induce lipid peroxidation in sensitive fungi, which may promote the ensuing loss of integrity in the plasma membrane. This direct effect on fungal membranes may contribute, at least in part, to the observed antimicrobial effects of these two salts.