bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of Transcriptional Regulatory Genes for Biphenyl Degradation in
Rhodococcus
sp. Strain RHA1
Authors: Takeda Hisashi , Yamada Akihiro , Miyauchi Keisuke , Masai Eiji , Fukuda Masao
Published: March 2004

Transcription of the
bphA1A2A3A4C1B
genes, which are responsible for the conversion of biphenyl and polychlorinated biphenyl to the
meta
-cleavage products in
Rhodococcus
sp. strain RHA1, was examined. The
bphA1
promoter (P

bphA1

) was identified and was shown to promote transcription induction by biphenyl and ethylbenzene. An 8.8-kb HindIII fragment that promotes transcription induction of P

bphA1

in
Rhodococcus erythropolis
IAM1399 was isolated from the region downstream of
bphB
by using a reporter plasmid containing P

bphA1

. Analysis of the nucleotide sequence of this fragment revealed a set of putative two-component regulatory system genes, which were designated
bphS
and
bphT
. Deletion analysis of the 8.8-kb HindIII fragment indicated that
bphT
is responsible for the basal activation of P

bphA1

and that both
bphS
and
bphT
are required for the elevated basal activation of and transcriptional induction by biphenyl of P

bphA1

. These results support the notion that
bphS
and
bphT
encode a sensor kinase and a response regulator, respectively, of a two-component regulatory system. The
bphS
and
bphT
genes promote transcriptional induction by a variety of aromatic compounds, including biphenyl, benzene, alkylbenzenes, and chlorinated benzenes. A promoter activity assay and reverse transcription (RT)-PCR analysis revealed a weak constitutive promoter in the adjacent region upstream of
bphS
. RT-PCR analysis indicated that there is induced transcription of
bphA1
through
bphT
, in which P

bphA1

is thought to take part. An insertionally inactivated
bphS
mutant, SDR1, did not grow on biphenyl. Growth was restored by introduction of an intact
bphS
gene into SDR1. These results indicate that at least
bphS
is indispensably responsible for the growth of RHA1 on biphenyl.
Selenocysteine-Containing Proteins in Anaerobic Benzoate Metabolism of
Desulfococcus multivorans
Authors: Peters Franziska , Rother Michael , Boll Matthias
Published: March 2004

The sulfate-reducing bacterium
Desulfococcus multivorans
uses various aromatic compounds as sources of cell carbon and energy. In this work, we studied the initial steps in the aromatic metabolism of this strictly anaerobic model organism. An ATP-dependent benzoate coenzyme A (CoA) ligase (AMP plus PP
i
forming) composed of a single 59-kDa subunit was purified from extracts of cells grown on benzoate. Specific activity was highest with benzoate and some benzoate derivatives, whereas aliphatic carboxylic acids were virtually unconverted. The N-terminal amino acid sequence showed high similarities with benzoate CoA ligases from
Thauera aromatica
and
Azoarcus evansii
. When cultivated on benzoate, cells strictly required selenium and molybdenum, whereas growth on nonaromatic compounds, such as cyclohexanecarboxylate or lactate, did not depend on the presence of the two trace elements. The growth rate on benzoate was half maximal with 1 nM selenite present in the growth medium. In molybdenum- and/or selenium-depleted cultures, growth on benzoate could be induced by addition of the missing trace elements. In extracts of cells grown on benzoate in the presence of [
75
Se]selenite, three radioactively labeled proteins with molecular masses of ∼100, 30, and 27 kDa were detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis. The 100- and 30-kDa selenoproteins were 5- to 10-fold induced in cells grown on benzoate compared to cells grown on lactate. These results suggest that the dearomatization process in
D. multivorans
is not catalyzed by the ATP-dependent Fe-S enzyme benzoyl-CoA reductase as in facultative anaerobes but rather involves unknown molybdenum- and selenocysteine-containing proteins.
Multiple Formaldehyde Oxidation/Detoxification Pathways in
Burkholderia fungorum
LB400
Authors: Marx Christopher J. , Miller Jonathan A. , Chistoserdova Ludmila , Lidstrom Mary E.
Published: March 2004

Burkholderia
species are free-living bacteria with a versatile metabolic lifestyle. The genome of
B. fungorum
LB400 is predicted to encode three different pathways for formaldehyde oxidation: an NAD-linked, glutathione (GSH)-independent formaldehyde dehydrogenase; an NAD-linked, GSH-dependent formaldehyde oxidation system; and a tetrahydromethanopterin-methanofuran-dependent formaldehyde oxidation system. The other
Burkholderia
species for which genome sequences are available,
B. mallei
,
B. pseudomallei
, and
B. cepacia
, are predicted to contain only the first two of these pathways. The roles of the three putative formaldehyde oxidation pathways in
B. fungorum
LB400 have been assessed via knockout mutations in each of these pathways, as well as in all combinations of knockouts. The resulting mutants have the expected loss of enzyme activities and exhibit defects of varying degrees of severity during growth on choline, a formaldehyde-producing substrate. Our data suggest that all three pathways are involved in formaldehyde detoxification and are functionally redundant under the tested conditions.
Evidence for Multiple Levels of Regulation ofOenococcus oeni clpP-clpLLocus Expression in Response to Stress
Authors: Beltramo Charlotte , Grandvalet Cosette , Pierre Fabrice , Guzzo Jean
Published: March 2004

A locus containing theclpPandclpLgenes in the lactic acid bacteriumOenococcus oeniwas studied. Real-time reverse transcription-PCR analysis revealed different induction factors involved in expression of these genes during stress. According to the conditions, clpPandclpLgenes could be transcripted as two distinct transcripts or cotranscripted. TheclpPpromoter depended on the CtsR regulator, but surprisingly theclpLpromoter did not. The amount of theclpLtranscript depended on mRNA stability. ThisclpATPase gene is at least controlled at the posttranscriptional level.
A Single Target Is Sufficient To Account for the Biological Effects of the A-Factor Receptor Protein ofStreptomyces griseus
Authors: Kato Jun-ya , Miyahisa Ikuo , Mashiko Mari , Ohnishi Yasuo , Horinouchi Sueharu
Published: March 2004

In the model of the A-factor (2-isocapryloyl-3R-hydroxymethyl-γ-butyrolactone) regulatory cascade inStreptomyces griseus, A-factor binds ArpA, the A-factor receptor protein, that has bound to theadpApromoter and dissociates it from the DNA, thus inducing the transcription ofadpA. AdpA switches on the transcription of a number of genes required for secondary metabolism and morphological differentiation, forming an AdpA regulon. Consistent with this model,arpAnull mutants produced streptomycin and a yellow pigment in larger amounts and formed aerial hyphae from an earlier growth stage than the wild-type strain. On the other hand, mutant MK2, expressing a mutant ArpA (Trp119Ala), neither produced secondary metabolites nor formed aerial hyphae, because this A-factor-insensitive mutant ArpA always bound to and repressed theadpApromoter due to the amino acid replacement of Trp-119 with Ala. Introduction ofadpAunder the control of a foreign promoter into mutant MK2 restored all of the phenotypes that we could observe, which suggests that the only significant target of ArpA isadpA. In contrast to other γ-butyrolactone regulatory systems, disruption ofarpAhad no effect on A-factor production, indicating that ArpA does not regulate A-factor biosynthesis. Instead, A-factor production was found to be repressed by AdpA in a two-step regulatory feedback loop.
Stochastic Processes Influence Stationary-Phase Decisions in
Bacillus subtilis
Authors: Maughan Heather , Nicholson Wayne L.
Published: March 2004

It has recently been proposed that phenotypic variation in clonal populations of bacterial species results from intracellular “noise,” i.e., random fluctuations in levels of cellular molecules, which would be predicted to be insensitive to selective pressure. To test this notion, we propagated five populations of
Bacillus subtilis
for 5,000 generations with selection for one phenotype: the decision to sporulate. In support of the noise hypothesis, we report that none of the populations responded to selection by improving their efficiency of sporulation, indicating that intracellular noise is independent of heritable genotype.
Influences of global change on carbon sequestration by agricultural and forest soils
Authors: Hendrickson Ole
Published: March 2004

Global change  including warmer temperatures, higher CO2 concentrations, increased nitrogen deposition, increased frequency of extreme weather events, and land use change  affects soil carbon inputs (plant litter), and carbon outputs (decomposition). Warmer temperatures tend to increase both plant litter inputs and decomposition rates, making the net effect on soil carbon sequestration uncertain. Rising atmospheric carbon dioxide levels may be partly offset by rising soil carbon levels, but this is the subject of considerable interest, controversy, and uncertainty. Current land use changes have a net negative impact on soil carbon. Desertification and erosion associated with overgrazing and excess fuelwood harvesting, conversion of natural ecosystems into cropland and pasture land, and agricultural intensification are causing losses of soil carbon. Losses increase in proportion to the severity and duration of damage to root systems. Strategic landscape-level deployment of plants through agroforestry systems and riparian plantings may represent an efficient way to rebuild total ecosystem carbon, while also stabilizing soils and hydrologic regimes, and enhancing biodiversity. Many options exist for increasing carbon sequestration on croplands while maintaining or increasing production. These include no-till farming, additions of nitrogen fertilizers and manure, and irrigation and paddy culture. Article 3.4 of the Kyoto Protocol has stimulated intense interest in accounting for land use change impacts on soil carbon stocks. Most Annex I parties are attempting to estimate the potential for increased agricultural soil carbon sequestration to partly offset their growing fossil fuel greenhouse gas emissions. However, this will require demonstrating and verifying carbon stock changes, and raises an issue of how stringent a definition of verification will be adopted by parties. Soil carbon levels and carbon sequestration potential vary widely across landscapes. Wetlands contain extremely important reservoirs of soil carbon in the form of peat. Clay and silt soils have higher carbon stocks than sandy soils, and show a greater and more prolonged response to carbon sequestration measures such as afforestation. Increased knowledge of soil organisms and their activities can improve our understanding of how soil carbon will respond to global change. New techniques using soil organic matter fractionation and stable C isotopes are also making major contributions to our understanding of this topic. Key words: climate change, carbon dioxide (CO2), nitrogen, soil respiration, land use change, plant roots, afforestation, no-till.
Aspects of floral morphology in Ambrosina and Arisarum (Araceae)
Authors: Barabé Denis , Lacroix Christian , Gibernau Marc
Published: March 2004

The floral morphology of Ambrosina and Arisarum is analysed from a developmental and phylogenetic point of view. In Arisarum, there are atypical organs displaying male and female characteristics. This developmental study shows that the male flowers of Ambrosina are di- or tri-androus. A close phylogenetic relationship between Ambrosina and Arisarum is supported by their morphology. Both genera have the same type of pollen (ellipsoid, inaperturate, striatereticulate) and the mode of dehiscence (by a longitudinal slit) of the thecae. In Arisarum, the pollen is mixed with extracellular prismatic crystals of calcium oxalate.Key words: atypical flowers, calcium oxalate crystals, flower development, phylogeny.
Impact of elevated nitrogen inputs on seedling growth of five dry tropical tree species as affected by life-history traits
Authors: Khurana Ekta , Singh J S
Published: March 2004

We examined whether the responses of dry tropical tree seedlings to elevated nitrogen (N) inputs were associated with functional types, and whether the growth traits of seedlings emerging from seeds of different size within a species were differentially affected by increased N inputs. The study comprised five dry tropical tree species: Albizia procera (Roxb.) Benth, Acacia nilotica (L.) Delile, Phyllanthus emblica L., Terminalia arjuna (Roxb.) Beddome, and Terminalia chebula Retz. Of these, Albizia procera, Acacia nilotica, and P. emblica are pioneer species. The former two are N-fixing legumes. Terminalia arjuna and T. chebula are nonpioneer, nonleguminous species. Albizia procera, P. emblica, and T. arjuna are fast growing, while the remaining two are slow-growing species. Seedlings of these species from large and small seeds were grown at four N input levels (0, 30, 60, and 120 kg N·ha1). Height and leaf area were measured periodically. At the end of the experiment (after 4 months) biomass and other growth traits, namely relative growth rate, net assimilation rate, specific leaf area, and root/shoot ratio, were determined. Foliar N and net CO2 assimilation rates were also determined. The species responded differentially (66%282% increase in biomass) to elevated N supply, but the response was not associated with between-species seed size variation. However, within species, small-seed seedlings exhibited a greater response. The elevated N input resulted in a greater enhancement in relative growth rate of the slow-growing species. The species response did not follow functional types such as pioneer versus nonpioneer, legumes versus nonlegumes, and deciduous versus evergreen, but rather was individualistic.Key words: Albizia procera, Acacia nilotica, Phyllanthus emblica, Terminalia arjuna, Terminalia chebula, elevated N input.
Characterizing polyploidy inArabidopsis lyratausing chromosome counts and flow cytometry
Authors: Dart Sara , Kron Paul , Mable Barbara K
Published: March 2004

Protocols were developed for both chromosome counts and flow cytometry to assess ploidy level and DNA content for populations of Arabidopsis lyrata L. sampled from Europe (Arabidopsis lyrata subsp. petraea), North America (Arabidopsis lyrata subsp. lyrata), and Japan (Arabidopsis lyrata subsp. kawasakiana). Ploidy variation within this species is not clear, with previous studies having documented both diploid and tetraploid populations. Chromosome counts in this study confirmed ploidy expectations for all populations examined. Individuals from Iceland and North America were diploid (2n = 2x = 16), whereas those from Japanese and Austrian populations were tetraploid (2n = 4x = 32). Flow cytometry was also used successfully to distinguish between ploidy levels, but the need to calibrate DNA content measures with chromosome counts was demonstrated by a deviation from the expected 2:1 ratio between tetraploid and diploid values among European populations (A. lyrata subsp. petraea). This deviation might be explained by a hybrid (allopolyploid) origin or by genomic changes following polyploidization, emphasizing the dynamic nature of polyploid genomes. Variation in DNA content among families was found only for North American populations, but these individuals were sampled from a broader geographic range than those from other regions.Key words: cytogenetics, flow cytometry, polyploidy, Arabidopsis lyrata, genome size, chromosome counts.
Extent and patterns of hybridization among the three species ofPopulusthat constitute the riparian forest of southern Alberta, Canada
Authors: Floate Kevin D
Published: March 2004

Three species of Populus (Salicaceae) overlap and hybridize in southern Alberta, Canada. Variation in leaf morphology throughout the region identifies five genetically distinct zones. The drainage of the Oldman River contains a pure zone of balsam poplar (Populus balsamifera L.), a pure zone of plains cottonwood (Populus deltoides Marsh.), plus overlap and hybrid zones of balsam poplar  narrowleaf cottonwood (Populus angustifolia James) and balsam poplar  narrowleaf cottonwood  plains cottonwood. The drainage of the Red Deer River contains a pure zone of balsam poplar, a pure zone of plains cottonwood, plus an overlap and hybrid zone of balsam poplar  plains cottonwood. Zones on both drainages coincide with an elevational gradient. Overlap and hybrid zones extend at least 700 river km (the length obtained by measuring distances between sites of hybridization on a river and its tributaries) combined across the two drainages. Principal components analyses on leaf morphology identify a pattern of bidirectional intro gression between sect. Tacamahaca (balsam poplar, narrowleaf cottonwood) species. These analyses also identify a pattern of unidirectional introgression between Tacamahaca and sect. Aigeiros (plains cottonwood) species, with F1hybrids backcrossing only with the Tacamahaca parent. This pattern of unidirectional introgression subsequently was assessed and supported with data from the drainages of Ashley Creek and the Ogden River, Utah, which contain hybrid and overlap zones between narrowleaf cottonwood (Tacamahaca) and Fremont cottonwood, Populus fremontii S. Watson (Aigeiros). Given its unique nature in terms of extent, health, and composition, and given the effect of plant hybrid zones on the ecology and evolution of their associated organisms, it is hoped that the current study will facilitate future research targeting conservation of this riparian forest in its full genetic complexity.Key words: Populus, hybridization, riparian, cottonwood, introgression.
Dynamics of genetic variation in Taxus baccata: local versus regional perspectives
Authors: Hilfiker Karin , Holderegger Rolf , Rotach Peter , Gugerli Felix
Published: March 2004

Increasing loss of habitat tends to reduce biodiversity at the inter- and intra-specific levels. Within species, the remaining diversity is often partitioned so that a great amount of neutral genetic variation is assigned to among-population variation. This implies reduced gene flow as a consequence of population isolation. We tested whether random amplified polymorphic DNA (RAPD) markers indicate population and (or) regional differentiation in Swiss populations of English yew (Taxus baccata L.), a dioecious forest tree species with scattered distribution. Our sampling included three northern Swiss regions, each containing four populations, and a central-Alpine region with two populations. Four RAPD primers, giving rise to 41 scorable marker bands, identified all but two sampled individuals as unique genotypes. Analyses of molecular variance (AMOVA) detected no significant differentiation among the three northern Swiss regions yet a marginally significant differentiation of these regions versus the central-Alpine region. Concordantly, Mantel tests revealed isolation by distance only when considering all 14 populations. We postulate that the inferred level of gene flow, through wind-borne pollen and occasional long-distance seed dispersal, prevents isolation by distance in northern Switzerland, where stands of T. baccata are relatively abundant. This perpetuates a coherent regional network of occurrences of T. baccata, as might be expected in a metapopulation.Key words: genetic variation, isolation by distance, metapopulation, population differentiation, RAPD-PCR, Taxus baccata.
Key differences in photosynthetic characteristics of nine species of intertidal macroalgae are related to their position on the shore
Authors: Skene Keith R
Published: March 2004

A study of the fluorescence characteristics, net photosynthetic rate, and dark respiration of nine species of intertidal macroalgae, from three divisions and from different positions on a rocky shore on the east coast of Scotland, was carried out to address the following questions: (i) Do algae at different positions along the shore respond differently to the stresses at these positions in terms of photosynthetic efficiency, net photosynthetic rate, and respiration, when fully hydrated? (ii) Do algal species at different positions respond differently, in terms of function, to desiccation, and can these responses be correlated with tolerance or intolerance to desiccation in terms of recovery? The present study demonstrated that algal species that occur higher on the shore have greater photosynthetic rates, respiration rates, maximum fluorescence / initial fluorescence ratios, and photosynthetic efficiencies while fully hydrated than do species that live lower on the shore. These findings point towards an increase in time-use efficiency in species that have less time available for productivity or nutrient uptake, since species at a greater height on the shore spend less time in a state of sufficient hydration to photosynthesize. Furthermore, algae higher up the shore, which can recover from desiccation, have significantly different fluorescence characteristics from nonrecoverers, particularly in the area above the Kautsky curve between initial fluorescence and maximum fluorescence. This is the first biophysical evidence relating to a mechanism for desiccation tolerance in macroalgae, and it is discussed within the context of other examples of increasing rates of physiological processes with decreasing time.Key words: fluorescence, zonation, function, rocky shore, Fucus.
Adhesion of decay-causing fungal conidia in wounds ofMalus×domestica'Golden Delicious' apple fruit is influenced by wound age
Authors: Filonow Alexander B
Published: March 2004

Wounds are the primary site in apple fruit for infection by conidia of Botrytis cinerea Pers.:Fr. and Penicil lium expansum Link & Thom. The effects of wound shape, wound age, and chemical properties of the wound on conidial adhesion in wounds of Malus ×domestica Borkh. 'Golden Delicious' fruit were investigated. Adhesion was measured after dislodging conidia from wounds using a sonication probe above the wound. In all experiments, conidial adhesion responses were similar for both fungi. Conidial adhesion in puncture wounds was not different from adhesion in slice wounds. Wound age, however, profoundly affected conidial adhesion. Conidia of both fungi exhibited 78.1%91.9% adhesion in freshly made wounds of both shapes compared with 37.7%56.6% in 1-d-old wounds. Conidial adhesion increased as wound age increased from 1 to 5 d. Exposure of 1- and 2-d-old wounds to butyl acetate, a volatile constituent of apple fruit, increased conidial adhesion compared with nonexposed wounds. This finding, in addition to results from the histochemical analyses of wounds, the quantification of sugars and total phenolics in water diffusates from wounds, and the measurement of conidial adhesion to wound diffusates, suggested that conidial adhesion in wounds was influenced by altered surface chemistry of wounds as they aged.Key words: apple fruit wounds, decay-causing fungi, fungal spore adhesion, mycoactive acetate esters, wound aging, wound decay.
Influence of nitrate level on nitrate assimilation in tomato (Lycopersicon esculentum) plants under saline stress
Authors: Flores Pilar , Botella M Ángeles , Cerdá Antonio , Martínez Vicente
Published: March 2004

This experiment was conducted to study the effect of salinity and different NO3 concentrations on NO3 uptake, transport, and reduction. To avoid the significant effect of plant size, the main difference from other studies was the short time period of treatment application. Tomato plants (Lycopersicon esculentum Mill. 'Asun') were grown for 11 d in half-strength Hoagland solution (with 7 mmol/L NO3) in a growth chamber under controlled conditions. After that, the different NO3 treatments were 0.5, 2, and 4 mmol/L NO3, and saline treatments consisted of two levels of NaCl: 0 (control) and 75 mmol/L. Under control conditions, an increase in NO3 concentration in the nutrient solution resulted in greater NO3 uptake, NO3 xylem flux, NO3- concentrations in tissues, and leaf and root nitrate reductase activity. However, when plants were exposed to salinity for a short period of time and the plant size or the shoot/root ratio was not an additional factor affecting the physiological parameters, the NO3 concentration in the solution slightly affected the different steps of NO3 assimilation.Key words: nitrate assimilation, nitrate reductase activity, nitrogen, salinity, tomato, Lycopersicon esculentum.
RATIONAL FAMILIES OF VECTOR BUNDLES ON CURVES
Authors: CASTRAVET ANA-MARIA
Published: March 2004

Let C be a smooth projective complex curve of genus g≥2 and let M be the moduli space of rank 2, stable vector bundles on C, with fixed determinant of degree 1. For any k≥1, we find all the irreducible components of the space of rational curves on M, of degree k. In particular, we find the maximal rationally connected fibrations of these components. We prove that there is a one-to-one correspondence between moduli spaces of rational curves on M and moduli spaces of rank 2 vector bundles on ℙ1×C.
SUPERSYMMETRY APPROACHES TO THE BOUND STATES OF THE GENERALIZED WOODS–SAXON POTENTIAL
Authors: FAKHRI H. , SADEGHI J.
Published: March 2004

Using the associated Jacobi differential equation, we obtain exactly bound states of the generalization of Woods–Saxon potential with the negative energy levels based on the analytic approach. According to the supersymmetry approaches in quantum mechanics, we show that these bound states by four pairs of the first-order differential operators, represent four types of the laddering equations. Two types of these supersymmetry structures, suggest the derivation of algebraic solutions by two different approaches for the bound states.
STRINGS, BRANES AND AN ACCELERATING UNIVERSE
Authors: KHURI RAMZI R.
Published: March 2004

Velocity-dependent interactions in a fundamental-string dominated universe lead quite naturally, with reasonable assumptions on initial conditions, to an accelerating expanding universe without assuming the existence of a cosmological constant. Using a mean-field approximation, exact solutions are obtained for various string/brane cosmological toy models. A multi-body model is also investigated. It is also shown that the repulsive velocity-dependent force arises in more general contexts and can lead to cosmic structure formation. Finally, we discuss a toy model including both ordinary and extremal matter, in which the latter accounts for dark matter while simultaneously acting as effective dark energy. Eternal acceleration is once more seen to arise in this case.
INCREASE OF THE ELECTRON–POSITRON HAWKING RADIATION FROM SCHWARZSCHILD BLACK HOLES BY DIRAC MONOPOLES
Authors: GONCHAROV YU. P. , FIRSOVA N. E.
Published: March 2004

An algorithm for numerical computation of the barrier transparency for the potentials surrounding Schwarzschild black holes is described for massive spinor particles. It is then applied to calculate the total (including electronic neutrino and the contributions of twisted field configurations connected with Dirac monopoles) luminosity for the electron–positron Hawking radiation from a Schwarzschild black hole with mass M=1015 g. It is found that the contribution due to monopoles can be of order 12% of the total electron–positron luminosity.
SPIN-STATISTICS THEOREM AND GEOMETRIC QUANTIZATION
Authors: ANASTOPOULOS CHARIS
Published: March 2004

We study the relation of the spin-statistics theorem to the geometric structures on phase space, which are introduced in quantization procedures (namely a U(1) bundle and connection). The relation can be proved in both the relativistic and the nonrelativistic domain (in fact for any symmetry group including internal symmetries) by requiring that the exchange can be implemented smoothly by a class of symmetry transformations that project in the phase space of the joint system system. We discuss the interpretation of this requirement, stressing the fact that any distinction of identical particles comes solely from the choice of coordinates — the exchange then arises from suitable change of coordinate system. We then examine our construction in the geometric and the coherent-state-path-integral quantization schemes. In the appendix we apply our results to exotic systems exhibiting continuous "spin" and "fractional statistics." This gives novel and unusual forms of the spin-statistics relation.
TRANSITION METALS EFFECT ON THE STRUCTURE OF PYRAZINAMIDE COMPLEXES
Authors: SIMON V. , JURCA T. , SIMON S.
Published: March 2004

Pyrazinamide (PZA) is among the first-line drugs for the treatment of tuberculosis, which seems to reappear as a frequent disease. In this study we investigate the structural changes induced in these samples as evidenced by thermal behaviour and electron spin resonance of new transition metal complexes of PZA. We is search for a correlation between structure and thermal transformations described as multi-step processes consisting in crystalline phase transition, decomposition, melting and thermo-oxidation.
QUASI-INVARIANCE FORMULAS FOR COMPONENTS OF QUANTUM LÉVY PROCESSES
Authors: FRANZ UWE , PRIVAULT NICOLAS
Published: March 2004

A general method for deriving Girsanov or quasi-invariance formulas for classical stochastic processes with independent increments obtained as components of Lévy processes on real Lie algebras is presented. Letting a unitary operator arising from the associated factorizable current representation act on an appropriate commutative subalgebra, a second commutative subalgebra is obtained. Under certain conditions the two commutative subalgebras lead to two classical processes such that the law of the second process is absolutely continuous w.r.t. to the first. Examples include the Girsanov formula for Brownian motion as well as quasi-invariance formulas for the Poisson process, the Gamma process,15,16 and the Meixner process.
Tissue heterogeneity in the mouse lung: effects of elastase treatment
Authors: Ito Satoru , Ingenito Edward P. , Arold Stephen P. , Parameswaran Harikrishnan , Tgavalekos Nora T. , Lutchen Kenneth R. , Suki Béla
Published: March 2004

We developed a network model in an attempt to characterize heterogeneity of tissue elasticity of the lung. The model includes a parallel set of pathways, each consisting of an airway resistance, an airway inertance, and a tissue element connected in series. The airway resistance, airway inertance, and the hysteresivity of the tissue elements were the same in each pathway, whereas the tissue elastance (H) followed a hyperbolic distribution between a minimum and maximum. To test the model, we measured the input impedance of the respiratory system of ventilated normal and emphysematous C57BL/6 mice in closed chest condition at four levels of positive end-expiratory pressures. Mild emphysema was developed by nebulized porcine pancreatic elastase (PPE) (30 IU/day × 6 days). Respiratory mechanics were studied 3 wk following the initial treatment. The model significantly improved the fitting error compared with a single-compartment model. The PPE treatment was associated with an increase in mean alveolar diameter and a decrease in minimum, maximum, and mean H. The coefficient of variation of H was significantly larger in emphysema (40%) than that in control (32%). These results indicate that PPE treatment resulted in increased time-constant inequalities associated with a wider distribution of H. The heterogeneity of alveolar size (diameters and area) was also larger in emphysema, suggesting that the model-based tissue elastance heterogeneity may reflect the underlying heterogeneity of the alveolar structure.
Malaysian Knowledge Society and the Global Knowledge Gap
Authors: Evers Hans-Dieter
Published: March 2004

Knowledge has been widely recognised as the most important factor of production in a "new economy". The production, dissemination and utilisation of knowledge are therefore essential for development. Some countries, Malaysia among others, have embarked on an ambitious plan to use knowledge as a base for economic development, by-passing earlier stages of industrialisation. Some commentators have, in contrast, asserted "that it is doubtful that the knowledge revolution will let developing countries leapfrog to higher levels of development" as "the knowledge economy will actually expand the gap between rich and poor" (Persaud, 2001:108). The paper discusses this controversy by arguing that the knowledge-gap (k-gap) is in fact a precondition for development. It is, however, no natural phenomenon but it is constructed by experts and governments. Socio-economic indicators are used to show that the existing global knowledge gap is widening between Southeast Asia and the OECD countries and within ASEAN. Malaysia, whose government has pursued a vigorous strategy of knowledge development is moving ahead of other ASEAN nations, but falling behind industrialised countries. Factors explaining the situation are outlined in this article.
Colonial Interventions on the Cultural Landscape of Central Sulawesi by "Ethical Policy": The Impact of the Dutch Rule in Palu and Kulawi Valley, 1905–1942
Authors: Kreisel Werner , Weber Robert , Faust Heiko
Published: March 2004

The colonial conquest of Palu and Kulawi Valley in western Central Sulawesi, Indonesia, is characterised by the so-called "ethical policy", which was introduced to Dutch colonial policy at the beginning of the 20th century. An in-depth analysis of Dutch colonial sources, the

memories van overgave

, which have never been analysed in such detail on the subject of cultural geography, reveals that almost all facets of cultural landscape were influenced by the Dutch rule. These sources also disclose the ambiguous use of

ethical policy

by justifying or withdrawing colonial intervention in this area.
Optimal Observations for Variational Data Assimilation
Authors: Köhl Armin , Stammer Detlef
Published: March 2004

An important part of ocean state estimation is the design of an observing system that allows for the efficient study of climate related questions in the ocean. A solution to the design problem is presented here in terms of optimal observations that emerge as singular vectors of the modified data resolution matrix. The actual computation is feasible only for scalar quantities and in the limit of large observational errors. Identical twin experiments performed in the framework of a 1° North Atlantic primitive equation model demonstrate that such optimal observations, when applied to determining the heat transport across the Greenland–Scotland ridge, perform significantly better than traditional section data. On seasonal to interannual time scales, optimal observations are located primarily along the continental shelf and information about heat transport, wind stress, and stratification is being communicated through boundary waves and advective processes. On time scales of about 1 month, sea surface height observations appear to be more efficient in reconstructing the cross-ridge heat transport than hydrographic observations. Optimal observations also provide a tool for understanding changes of ocean state associated with anomalies of integral quantities such as meridional heat transport.
Direct Observations of Along-Isopycnal Upwelling and Diapycnal Velocity at a Shelfbreak Front*
Authors: Barth John A. , Hebert Dave , Dale Andrew C. , Ullman David S.
Published: March 2004

By mapping the three-dimensional density field while simultaneously tracking a subsurface, isopycnal float, direct observations of upwelling along a shelfbreak front were made on the southern flank of Georges Bank. The thermohaline and bio-optical fields were mapped using a towed undulating vehicle, and horizontal velocity was measured with a shipboard acoustic Doppler current profiler. A subsurface isopycnal float capable of measuring diapycnal flow past the float was acoustically tracked from the ship. The float was released near the foot of the shelfbreak front (95–100-m isobath) and moved 15 km seaward as it rose from 80 to 50 m along the sloping frontal isopycnals over a 2-day deployment. The float's average westward velocity was 0.09 m s−1, while a drifter drogued at 15 m released at the same location moved westward essentially alongfront at 0.18 m s−1. The float measured strong downward vertical velocities (in excess of 0.02 m s−1) associated with propagation of internal tidal solibores in the onbank direction from their formation near the shelf break. The float measured large upward vertical velocities (in excess of 0.001 m s−1 ≃ 100 m day−1) as the pycnocline rebounded adiabatically after the passage of the internal tide solibore. The directly measured mean along-isopycnal vertical velocity was 17.5 m day−1. Intense mixing events lasting up to 2 hours were observed in the shelfbreak front at the boundary between cold, fresh shelf water and warm, salty slope water. Diapycnal velocities of up to 3 × 10−3 m s−1 were measured, implying a diapycnal thermal diffusivity as large as 10−2 m2 s−1, indicative of strong mixing events in this coastal front.
The Origin, Pathway, and Destination of Niño-3 Water Estimated by a Simulated Passive Tracer and Its Adjoint
Authors: Fukumori Ichiro , Lee Tong , Cheng Benny , Menemenlis Dimitris
Published: March 2004

The nature of subtropical–tropical water mass exchange in the Pacific Ocean is investigated, focusing on the origin, pathway, and destination of water occupying the surface layer of the eastern equatorial Pacific Ocean (Niño-3 region; 5°S–5°N, 150°–90°W). Simulated passive tracers and their adjoint are employed to explicitly follow the circulation of specific water masses accounting for advective and diffusive effects and their time variabilities. The evolution of the forward passive tracer and adjoint passive tracer can be identified as describing where the tracer-tagged water mass goes and from where it comes, respectively. Over 10 years on average, water mass of the Niño-3 region can be traced back to eastern subtropical thermocline waters of the Northern (27%) and Southern Hemispheres (39%). The Niño-3 water subsequently returns to these subtropical latitudes in the upper ocean. In contrast to the hypothesized “subtropical cell,” however, this circulation is an open circuit with water returning to the western regions of the two hemispheres (subtropical gyres) and to the Indian Ocean, instead of returning to its origins. The representative transit time scale from the subtropics to the Tropics is 10–15 yr. Temporal variability causes the tropical circulation inferred from a time-mean state to differ significantly from the average circulation. In particular, stirring due to nonseasonal, intra-annual variability significantly enhances the transport magnitude of the so-called interior pathways relative to that of the circuitous low-latitude western boundary pathways. Such short-circuit in the subtropical–tropical exchange may help better to explain tracer distributions, such as the observed midbasin tritium maximum in the equatorial Pacific Ocean. Significant differences in circulation pathways are also identified that are associated with El Niño and La Niña events. The strength of the subtropical–tropical water mass exchange is estimated to have weakened during the 1990s.
The Meandering Path of a Drifter around the Western Alboran Gyre
Authors: García Lafuente Jesús , Delgado Javier
Published: March 2004

An accidentally released drifter in the eastern section of the Strait of Gibraltar, whose successive positions were tracked by the Argos surveillance system, was advected more than 170 km around the western Alboran gyre in the Alboran Sea of the western Mediterranean Sea during four days. The drifter trajectory along the gyre's periphery was wavelike around a hypothetical smoothed streamline, with a period of 35 h and an amplitude of approximately 2 km. Temperature observations confirm the wavelike nature of the trajectory. Neither tidal currents within the Alboran basin nor wind-related forcing are able to explain the observed path. The interaction of the incoming Atlantic jet and the western Alboran gyre at the place where they meet together with the existence of relative vorticity pulses of the Atlantic jet associated with tidal currents in the strait is put forward as a likely mechanism that generates short-scale eddies in which the drifter could have been trapped. The subsequent advection of such an eddy around the gyre would depict the observed wavelike trajectory.
SST Assimilation Experiments in a Tropical Pacific Ocean Model
Authors: Tang Youmin , Kleeman Richard , Moore Andrew M.
Published: March 2004

With a simple 3DVar assimilation algorithm, a new scheme of assimilating sea surface temperature (SST) observations is proposed in this paper. In this new scheme, the linear relation between any two neighboring depths was derived using singular value decomposition technique and then was applied to estimate the temperatures at deeper levels using the temperature analyses at shallower levels. The estimated temperatures were assimilated into an ocean model, and the procedure was run iteratively at each time step from the surface to a depth of 250 m. The oceanic analyses show that the new scheme can more effectively adjust oceanic thermal and dynamical fields and lead to a more realistic subsurface thermal structure when compared with the control run and another scheme that is usually used for SST assimilation. An ensemble of predictions for the Niño-3 region SST anomalies was performed to test the new scheme. It was found that the new scheme can improve fairly well ENSO prediction skills at all lead times, in particular for anomalous warm events, and for lead times of 4–7 months.
Preload-independent mechanisms contribute to increased stroke volume following large volume saline infusion in normal volunteers: a prospective interventional study
Authors: Kumar Anand , Anel Ramon , Bunnell Eugene , Zanotti Sergio , Habet Kalim , Haery Cameron , Marshall Stephanie , Cheang Mary , Neumann Alex , Ali Amjad , Kavinsky Clifford , Parrillo Joseph E
Published: March 2004

Introduction

Resuscitation with saline is a standard initial response to hypotension or shock of almost any cause. Saline resuscitation is thought to generate an increase in cardiac output through a preload-dependent (increased end-diastolic volume) augmentation of stroke volume. We sought to confirm this to be the mechanism by which high-volume saline administration (comparable to that used in resuscitation of shock) results in improved cardiac output in normal healthy volunteers.

Methods

Using a standardized protocol, 24 healthy male (group 1) and 12 healthy mixed sex (group 2) volunteers were infused with 3 l normal (0.9%) saline over 3 hours in a prospective interventional study. Individuals were studied at baseline and following volume infusion using volumetric echocardiography (group 1) or a combination of pulmonary artery catheterization and radionuclide cineangiography (group 2).

Results

Saline infusion resulted in minor effects on heart rate and arterial pressures. Stroke volume index increased significantly (by approximately 15–25%; P < 0.0001). Biventricular end-diastolic volumes were only inconsistently increased, whereas end-systolic volumes decreased almost uniformly. Decreased end-systolic volume contributed as much as 40–90% to the stroke volume index response. Indices of ventricular contractility including ejection fraction, ventricular stroke work and peak systolic pressure/end-systolic volume index ratio all increased significantly (minimum P < 0.01).

Conclusion

The increase in stroke volume associated with high-volume saline infusion into normal individuals is not only mediated by an increase in end-diastolic volume, as standard teaching suggests, but also involves a consistent and substantial decrease in end-systolic volumes and increases in basic indices of cardiac contractility. This phenomenon may be consistent with either an increase in biventricular contractility or a decrease in afterload.
Relevance of Imidazoline Receptors and Agmatine to Psychiatry: A Decade of Progress
Authors: HALARIS A , PILETZ J E.
Published: March 2004

Abstract: The cardiovascular relevance of imidazoline receptors (IR) has received tremendous attention since their discovery in 1984. However, evidence also has accumulated for the relevance of IR and an endogenous ligand, agmatine, to psychiatric disease. Emphasis has been placed on altered levels of the I1‐imidazoline site on human platelets and in human postmortem brain tissue from depressed patients. Attempts at exploring the molecular nature of the I1 protein have led to the cloning of a protein, IRAS. Based on transfection studies, IRAS seems to be involved in neuronal plasticity events. The I2 site also appears linked to psychiatric research since some of these sites are localized to a specific domain on monoamine oxidases. Different peptides have been identified by means of an imidazoline‐receptor‐binding‐protein (IRBP) antiserum, and these peptides, some of which appear to be fragments derived from IRAS, undergo changes in platelets and brain commensurate with altered mood states of the subject, notably depressive symptomatology. The search for an endogenous ligand for imidazoline receptor(s) also has led to agmatine, a decarboxylated derivative of arginine. Research on agmatine has mushroomed over the past several years and its measurement in the blood and brain has opened new research opportunities. This novel neurotransmitter interacts with a variety of receptors and has been implicated in mediation of stress responses, analgesia, drug addiction and withdrawal, convulsions, and neuroprotection. Given that IR and agmatine appear involved in a multitude of neurophysiologic and pathologic functions, the potential for new drug development is intriguing.
Regulation of Inducible Nitric Oxide Synthase and Agmatine Synthesis in Macrophages and Astrocytes
Authors: REGUNATHAN SOUNDAR , PILETZ JOHN E.
Published: March 2004

Abstract: Agmatine is a novel endogenous guanido amine synthesized from arginine by arginine decarboxylase. Among several biologic effects, the ability of agmatine to protect against ischemic injury and chronic neuropathic pain is particularly interesting. Because inflammation is a common contributor to these conditions, we sought to determine if agmatine acts by decreasing the production of proinflammatory molecules such as nitric oxide and if agmatine synthesis is regulated by inflammatory stimuli. We tested whether agmatine affects astroglial and macrophage (RAW 264.7 cell line) nitric oxide synthase‐2 (NOS‐2) expression. NOS‐2 was induced in these cells by incubation with lipopolysaccharide (LPS) plus three cytokines for astrocytes and LPS alone for RAW 264.7 cells in the presence and absence of varying concentrations of agmatine. NOS‐2 activity was assessed after 24 hours by nitrite accumulation in the culture media. Agmatine dose‐dependently inhibited nitrite accumulation, and shorter incubation with agmatine (1 and 4 hours) also caused significant reduction. Agmatine decreased the expression of NOS‐2 activity and NOS‐2 protein as determined by immunoblot analysis. Incubation of astrocytes and RAW 264.7 cells with LPS/cytokines for 2 hours resulted in an increase in arginine decarboxylase (ADC) activity, whereas longer‐term incubation (12–17 hours) lowered ADC activity. Agmatine levels in these cells are increased after 6‐hour incubation with LPS/cytokines. These results show that agmatine inhibits the production of nitric oxide by decreasing the activity of NOS‐2 in macrophages and astroglial cells by decreasing the levels of NOS‐2 protein. These findings provide a molecular basis for the neuroprotective and anti‐inflammatory actions of agmatine.