bluuebunny/crossref_metadata_2025 huggingface dataset:
Regulation of granulocyte apoptosis by NF-κB
Authors: Ward C. , Walker A. , Dransfield I. , Haslett C. , Rossi A.G.
Published: June 2004

Granulocyte apoptosis is a crucial part of the successful resolution of inflammation. In vitro results show that activation of NF-κB (nuclear factor κB) in granulocytes is a survival mechanism. NF-κB inhibitors increase the rate of constitutive apoptosis in neutrophils and eosinophils and cause these cells to respond to the pro-apoptotic effects of TNF-α (tumour necrosis factor-α). Results from both in vivo and in vitro experiments suggest that there are at least two important waves of NF-κB activation in inflammatory loci, which increase the expression of COX-2 (cyclooxygenase-2), itself an NF-κB controlled gene. The first wave causes the production of inflammatory mediators such as PGE2 (prostaglandin E2), allowing the establishment of inflammation. The second wave causes the synthesis of PGD2 and its metabolites that induce granulocyte apoptosis by inhibiting NF-κB activation. These metabolites may therefore be important physiological mediators controlling the resolution of inflammation. Although NF-κB is an important target for anti-inflammatory therapy, the timing of inhibition in vivo may be crucial, to ensure that production of PGD2 and its sequential metabolites can occur.
An apoptosis differentiation programme in human polymorphonuclear leucocytes
Authors: Kobayashi S.D. , DeLeo F.R.
Published: June 2004

Human PMNs (polymorphonuclear leucocytes or neutrophils) are essential to the innate immune response against bacterial pathogens and are a key part of the acute inflammatory response. Although progress has been made, the molecular basis for termination of inflammation during bacterial infection in humans is largely undefined. To that end, we used genomics strategies to gain new insight into processes that facilitate resolution of neutrophil-mediated inflammation and bacterial infection. On the basis of a series of recent studies, we propose that global changes in PMN gene expression after phagocytosis comprise an apoptosis differentiation programme, which represents the final stage of transcription-regulated PMN maturation. Our studies indicate that the apoptosis differentiation programme regulates multiple post-phagocytic processes in human neutrophils, such as cell fate and proinflammatory activity, and is modulated by PMN-derived reactive oxygen species. Collectively, these studies establish a global model of host cell–pathogen interaction, which provides fundamental insight into the resolution of infection in humans.
Mammalian Sterile20-like kinase 1 and the regulation of apoptosis
Authors: de Souza P.M. , Lindsay M.A.
Published: June 2004

Mammalian Sterile20-like kinase 1 (Mst1) is a ubiquitously expressed serine/threonine kinase which represents a member of the rapidly expanding family of enzymes related to the yeast Sterile20 kinase. Although the physiological function of Mst1 and its role in intracellular signalling is still unclear, reports to date suggest that Mst1, similar to its yeast homologue, operates in the MAPK (mitogen-activated protein kinase) pathway and, in this capacity, may represent a putative MAPK kinase kinase kinase. Moreover, there is abundant evidence for a role of this enzyme in apoptosis, where not only is it a target for caspases, but may also serve as an activator of these proteases to amplify the apoptotic signalling pathway. This paper reviews the investigations that have led to our current understanding of the mechanisms by which Mst1 may be activated and thereby contribute to apoptosis.
Macrophage apoptosis in host immunity to mycobacterial infections
Authors: Fairbairn I.P.
Published: June 2004

Macrophage apoptosis occurs within the granuloma, which is essential for successful immunity to tuberculosis. In vitro macrophage apoptosis is associated with the killing of intracellular Mycobacterium tuberculosis. A greater understanding of these observations will lead to new immunotherapies and improved vaccine design. The relevant apoptotic stimuli, the anti-mycobacterial mechanisms that they stimulate and their physiological relevance are reviewed in this paper.
The role of oxidants and vitamin C on neutrophil apoptosis and clearance
Authors: Vissers M.C.M. , Hampton M.B.
Published: June 2004

We have investigated the role of neutrophil oxidants in the surface changes that result in recognition and uptake of neutrophils by macrophages. We have shown that H2O2 produced by stimulated neutrophils is essential for the surface expression of phosphatidylserine. This does not occur in neutrophils from mice with chronic granulomatous disease and may explain the formation of granuloma in this condition. We have also investigated the role of intracellular vitamin C on neutrophil apoptosis. Cells from vitamin C-deficient mice were found to be less likely to undergo both spontaneous and oxidant-induced apoptosis, with eventual necrosis being the most probable outcome.
Advances in two-dimensional gel matching technology
Authors: Church S.
Published: June 2004

For many years, two-dimensional gel electrophoresis has been the method of choice for the investigation of complex mixtures of proteins. Although there are a number of emerging technologies that can be applied to proteomics, none can yet yield routinely the breadth of information available from two-dimensional gels. To be able to obtain instant information regarding molecular mass and pI, as well as to highlight quickly the expression changes or unique proteins across a gel series requires sophisticated and powerful image analysis software. The range of software products offered by Nonlinear Dynamics covers all levels of user application and throughput, from the user-guided Phoretix two-dimensional approach, when working with a small number of gels, to the automatic processing of large numbers of gels with minimal user intervention with Progenesis. Integration of the analysis software with powerful database components allows advanced gel comparisons and data mining to be performed with statistical verification of the results. Spot pick lists can be quickly created and automatically linked to a number of commercially available spot picking robots further increasing the support for proteomics research. The importance of image analysis for accurate, reliable and meaningful results will be discussed. Recent advances in development, with particular attention placed on the impact of noise contamination within gels, are illustrated and how the Progenesis product from Nonlinear Dynamics can be utilized to get the most from two-dimensional gel electrophoresis is shown.
Aspects of the barley seed proteome during development and germination
Authors: Finnie C. , Maeda K. , Østergaard O. , Bak-Jensen K.S. , Larsen J. , Svensson B.
Published: June 2004

Analysis of the water-soluble barley seed proteome has led to the identification of proteins by MS in the major spots on two-dimensional gels covering the pI ranges 4–7 and 6–11. This provides the basis for in-depth studies of proteome changes during seed development and germination, tissue-specific proteomes, cultivar differences related to quality parameters, analysis of the genetic basis for spot variations and targeted investigations of specific proteins.
Proteomic analysis of the Arabidopsis cell wall reveals unexpected proteins with new cellular locations
Authors: Slabas A.R. , Ndimba B. , Simon W.J. , Chivasa S.
Published: June 2004

We initiated a proteomic study as part of a programme aimed at discovering novel functions of the plant cell wall. Cell-wall fragments isolated from cell-suspension cultures of Arabidopsis thaliana were stripped of protein sequentially using CaCl2 and a urea-based buffer. The protein fractions were separated by two-dimensional gel electrophoresis and individual proteins were identified by MS. We identified a number of proteins considered to be resident in other organelles but not the cell wall on the basis of their classical biological function. These included citrate synthase, which is known to be targeted to mitochondria, peroxisomes and glyoxysomes, and luminal binding protein, which is an ER (endoplasmic reticulum)-resident protein. Searches of the Arabidopsis database revealed that there are several genes encoding putative citrate synthase and luminal binding protein. We have also performed detailed analyses of the protein sequences and this paper shows how each one contains encrypted targeting information that results in the export of the protein to the extracellular matrix. We discuss the presence of alternative non-classical secretory pathways in plants.
The Cys-loop superfamily of ligand-gated ion channels: the impact of receptor structure on function
Authors: Connolly C.N. , Wafford K.A.
Published: June 2004

The Cys-loop receptors constitute an important superfamily of LGICs (ligand-gated ion channels) comprising receptors for acetylcholine, 5-HT3 (5-hydroxytryptamine; 5-HT3 receptors), glycine and GABA (γ-aminobutyric acid; GABAA receptors). A vast knowledge of the structure of the Cys-loop superfamily and its impact on channel function have been accrued over the last few years, leading to exciting new proposals on how ion channels open and close in response to agonist binding. Channel opening is initiated by the extracellular association of agonists to discrete binding pockets, leading to dramatic conformational changes, culminating in the opening of a central ion pore. The importance of channel structure is exemplified in the allosteric modulation of channel function by the binding of other molecules to distinct sites on the channel, which exerts an additional level of control on their function. The subsequent conformational changes (gating) lead to channel opening and ion transport. Following channel pore opening, ion selectivity is determined by receptor structure in, and around, the ion pore. As a final level of control, cytoplasmic determinants control the magnitude (conductance) of ion flow into the cell. Thus the Cys-loop receptors are complex molecular motors, with moving parts, which can transduce extracellular signals across the plasma membrane. Once the full mechanical motions involved are understood, it may be possible to design sophisticated therapeutic agents to modulate their activity, or at least be able to throw a molecular spanner into the works!
The transmembrane domain of the 5-HT3 receptor: its role in selectivity and gating
Authors: Lummis S.C.R.
Published: June 2004

The 5-HT3 (5-hydroxytryptamine) receptor is a typical member of the Cys-loop family of ligand-gated ion channels. No atomic resolution structures of these proteins have yet been published, and thus structure–function relationships in this family of proteins have been largely determined from experimental evidence combined with the use of homologous proteins and lower resolution images. Here, recent advances in our knowledge of the structure and function of the transmembranous part of the 5-HT3 receptor are reviewed. These show that the pore region, M2, is largely α-helical, and ion selectivity may be controlled by charged amino acid rings at each end of this pore region. The mechanism by which the pore opens is probably similar to that proposed for the nACh receptor, i.e. a twist of M2, caused by rotation in the extracellular domains, removes hydrophobic residues from the ion path.
Structural elements involved in activation of the γ-aminobutyric acid type A (GABAA) receptor
Authors: Kash T.L. , Trudell J.R. , Harrison N.L.
Published: June 2004

Ligand-gated ion channels function as rapid signal transducers, converting chemical signals (in the form of neurotransmitters) into electrical signals in the postsynaptic neuron. This is achieved by the recognition of neurotransmitter at its specific-binding sites, which then triggers the opening of an ion channel (‘gating’). For this to occur rapidly (<1 ms), there must be an efficient coupling between the agonist-binding site and the gate, located more than 30 Å (1 Å=0.1 nm) away. Whereas a great deal of progress has been made in elucidating the structure and function of both the agonist-binding site and the ion permeation pathway in ligand-gated ion channels, our knowledge of the coupling mechanism between these domains has been limited. In this review, we summarize recent studies of the agonist-binding site and the ion channel in the γ-aminobutyric acid type A receptor, and discuss those structural elements that may mediate coupling between them. We will also consider some possible molecular mechanisms of receptor activation.
Differentiating the role of γ-aminobutyric acid type A (GABAA) receptor subtypes
Authors: Wafford K.A. , Macaulay A.J. , Fradley R. , O'Meara G.F. , Reynolds D.S. , Rosahl T.W.
Published: June 2004

The inhibitory tone maintained throughout the central nervous system relies predominantly on the activity of neuronal GABAA (γ-aminobutyric acid type A) receptors. This receptor family comprises various subtypes that have unique regional distributions, but little is known about the role played by each subtype. The majority of the receptors contain a γ2 subunit and are sensitive to modulation by BZs (benzodiazepines), but differ with regard to α and β subunits. Mutagenesis studies combined with molecular modelling have enabled a greater understanding of receptor structure and dynamics. This can now be extended to in vivo activity through translation to genetically modified mice containing these mutations. Ideally, the mutation should leave normal receptor function intact, and this is the case with mutations affecting the BZ-binding site of the GABAA receptor. We have generated mutations, which affect the BZ site of different α subunits, to enable discrimination of the various behavioural consequences of BZ drug action. This has aided our understanding of the roles played by individual GABAA receptor subtypes in particular behaviours. We have also used this technique to explore the role of different β subunits in conferring the anaesthetic activity of etomidate. This technique together with the development of subtype-selective compounds facilitates our understanding of the roles played by each receptor subtype.
Modulational instability of dust envelope waves with grain and charge distribution
Authors: Duan Wen-shan , Parkes John , Zhang Lei
Published: June 2004

A reasonable normalization for a dusty plasma with many different species of dust grains is adopted. By applying a reductive perturbation technique to the equations governing a dusty plasma with N different species of dust grains, a nonlinear Schrödinger equation (NSLE) is derived that governs the modulation of dust-acoustic waves. The effect of dust size and charge distribution on the modulational instability of these waves is studied. If there are positively charged dust grains, which is a possibility suggested by experimental results, the envelope soliton solutions to the NLSE may be different from the ones associated with a dusty plasma containing mono-sized dust grains. The instability properties may also be different. In the former case the instability region depends on the percentage of electrons residing on the dust grains. In particular, if the number of electrons residing on the dust grains is small enough, the envelope waves are unstable.
Analysis of the memory effect in a nitrogen-filled tube at 6.6 mbar pressure for different cathode materials using the time delay method
Authors: Pejović Momčilo M.
Published: June 2004

The memory effect, due to postafterglow survival of some species which affect subsequent breakdown, was analyzed from the behavior of memory curves. In early afterglow, up to several tens of a millisecond, the memory effect in nitrogen is a consequence of the presence of positive ions formed by the collision between metastable molecules and highly vibrationally excited molecules remaining from the previous discharge. In late afterglow, the memory effect is due to N(4S) atoms created during the previous discharge and in early afterglow. When the atom density is reduced enough the breakdown is initiated by cosmic rays which always exists. In late afterglow in nitrogen the memory effect is very sensitive on cathode material.
Riemann functions and the group E(1,1)
Authors: Zeitsch Peter J.
Published: June 2004

Historically Lie algebras of first-order symmetry operators have proven to be a useful method for finding equivalence classes of Riemann functions. Here this idea is extended to higher order symmetries. The approach is to seek self-adjoint linear hyperbolic partial differential equations that separate variables in more than one coordinate system under the action of the group E(1,1). The equations derived admit no nontrivial first-order operators and can only be obtained from second-order symmetry operators. Using this symmetry structure, a new equivalence class of Riemann functions can then be found.
Symmetry operators for Riemann’s method
Authors: Zeitsch Peter J.
Published: June 2004

Riemann’s method is one of the definitive ways of solving Cauchy’s problem for a second order linear hyperbolic partial differential equation in 2 variables. Chaundy’s equation, with 4 parameters, is the most general self-adjoint equation for which the Riemann function is known. Here we show that Chaundy’s equation possesses a two-dimensional vector space of second-order symmetry operators. Hence a new equivalence class of Riemann functions, admitting no first-order symmetries and obtainable only via a higher order symmetry, is found. A new 5 parameter Riemann function is then subsequently derived.
Molecular dynamics study of kinetic boundary condition at an interface between argon vapor and its condensed phase
Authors: Ishiyama Tatsuya , Yano Takeru , Fujikawa Shigeo
Published: June 2004

The evaporation and condensation at an interface of vapor and its condensed phase is considered. The validity of kinetic boundary condition for the Boltzmann equation, which prescribes the velocity distribution function of molecules outgoing from the interface, is investigated by the numerical method of molecular dynamics for argon. From the simulations of evaporation into vacuum, the spontaneous-evaporation flux determined by the temperature of condensed phase is discovered. Condensation coefficient in equilibrium states can then be determined without any ambiguity. It is found that the condensation coefficient is close to unity below the triple-point temperature and decreases gradually as the temperature rises. The velocity distribution of spontaneously evaporating molecules is found to be nearly a half-Maxwellian at a low temperature. This fact supports the kinetic boundary condition widely used so far. At high temperatures, on the other hand, the velocity distribution deviates from the half-Maxwellian.
Effects of a slow ion beam on ion-acoustic waves
Authors: Nakamura Y. , Bailung H. , Ichiki R.
Published: June 2004

The influence of a slow ion beam on an ion-acoustic wave is studied theoretically and experimentally. A kinetic dispersion relation of an ion-beam–plasma system predicts a critical value of the ion-beam density above which the ion-acoustic wave is transformed into the fast mode of the ion beam. Below the critical value, the ion-acoustic wave propagates without transforming into the fast mode of space charge waves for any beam velocity. A dispersion relation based on a fluid model does not provide such a critical value for the ion-beam density. Experimentally, the ion-beam density is controlled carefully to test the presence of the critical density at which the change in topology of dispersion roots appears.
Spectroscopic measurements of plasma rotation and ion and neutral atom temperatures in the Maryland Centrifugal Experiment
Authors: Ghosh J. , Elton R. C. , Griem H. R. , Case A. , Ellis R. , Hassam A. B. , Messer S. , Teodorescu C.
Published: June 2004

In initial spectroscopic measurements on the Maryland Centrifugal Experiment, rotation velocities and directions for C+, C2+, C3+, and N+ ions and neutral hydrogen atoms have been obtained from the Doppler shifts of visible spectral lines. Ion and neutral temperatures have also been determined from Doppler broadening. Different rotation velocities and temperatures are observed for different species indicating that the inner plasma is hotter and rotates more rapidly than that at the edge. The direction of rotation is found to be consistent with the predicted Er¯×Bz¯ direction; and it reverses with the direction of the magnetic field. The magnitudes of the rotation velocities were of the same order as estimated from the applied voltage and magnetic field. For the C+, C2+, and C3+ species, rotation velocities of 20–30 km/s, 40–70 km/s, and 60–100 km/s are observed, respectively. The corresponding temperatures are 10–12 eV, 20–40 eV, and 25–40 eV. Neutral hydrogen atoms are observed to rotate with velocities ∼10 km/sec and with temperatures ∼5–10 eV. A figure of merit for centrifugal confinement is the thermal Mach number, M=(vφ/vthi), where vthi is the ion thermal speed. The observed ion velocities and temperatures correspond to M ranging from 1 to 2. Variations of rotation velocities and temperatures with axial magnetic field, radial electric field, and mirror ratio are described. An electron temperature of ≈15 eV is inferred from the relative line intensities from different ionic species of carbon, which is consistent with the lack of observable C4+ emission.
Invariant and group theoretical integrations over the U(n) group
Authors: Aubert S. , Lam C. S.
Published: June 2004

In a previous article, an “invariant method” to calculate monomial integrals over the U(n) group was introduced. In this paper, we study the more traditional group-theoretical method, and compare its strengths and weaknesses with those of the invariant method. As a result, we are able to introduce a “hybrid method” which combines the respective strengths of the other two methods. There are many examples in the paper illustrating how each of these methods works.
SLE-type growth processes and the Yang–Lee singularity
Authors: Lesage Frédéric , Rasmussen Jørgen
Published: June 2004

The recently introduced SLE growth processes are based on conformal maps from an open and simply connected subset of the upper half-plane to the half-plane itself. We generalize this by considering a hierarchy of stochastic evolutions mapping open and simply connected subsets of smaller and smaller fractions of the upper half-plane to these fractions themselves. The evolutions are all driven by one-dimensional Brownian motion. Ordinary chordal SLE appears at grade one in the hierarchy. At grade two we find a direct correspondence to conformal field theory through the explicit construction of a level-four null vector in a highest-weight module of the Virasoro algebra. This conformal field theory has central charge c=−22/5 and is associated with the Yang–Lee singularity. Our construction may thus offer a novel description of this statistical model.
Group classification of (1+1)-dimensional Schrödinger equations with potentials and power nonlinearities
Authors: Popovych Roman O. , Ivanova Nataliya M. , Eshraghi Homayoon
Published: June 2004

We perform the complete group classification in the class of nonlinear Schrödinger equations of the form iψt+ψxx+|ψ|γψ+V(t,x)ψ=0, where V is an arbitrary complex-valued potential depending on t and x, γ is a real nonzero constant. We construct all the possible inequivalent potentials for which these equations have nontrivial Lie symmetries using a combination of algebraic and compatibility methods. The proposed approach can be applied to solving group classification problems for a number of important classes of differential equations arising in mathematical physics.
Solute flows from Hordeum vulgare to the hemiparasite Rhinanthus minor and the influence of infection on host and parasite nutrient relations
Authors: Jiang Fan , Jeschke W. Dieter , Hartung Wolfram
Published: June 2004

Using the facultative root hemiparasite Rhinanthus minor and Hordeum vulgare L. as a host, the flows and partitioning of mineral nutrients within the host, the parasite and between host and parasite have been studied during the study period 41–54 d after planting, i.e approximately 30–43 d after successful attachment of the parasite to the host. In parasitising Rhinanthus shoot growth was 12-fold, but root growth only 2-fold increased compared to non-parasitising plants. Conversely, in the Hordeum host, shoot dry matter growth was clearly reduced, by 33% in leaf laminae and by 52% in leaf sheaths, whereas root growth was only slightly reduced as a consequence of parasitism. Growth-dependent increments of total nitrogen (N) and phosphorus (P) and of potassium (K), calcium (Ca) and magnesium (Mg) in parasitising Rhinanthus shoot were strongly increased, particularly increments of total N and P, which were 18 and 42 times, respectively, higher than in solitary Rhinanthus. However, increments of the above mineral nutrients in leaf sheaths of parasitised Hordeum vulgare were more strongly decreased than in leaf laminae in response to parasitic attack. Estimation of the flows of nutrients revealed that Rhinanthus withdrew from the host xylem sap about the same percentage of each nutrients: 18% of total N, 22% of P and 20% of K. Within the host almost all net flows of nutrient ions were decreased due to parasitism, but retranslocation from shoot to root was somewhat increased for all nutrients. Quantitative information is provided to show that the substantially increased growth in the shoot of attached Rhinanthus and the observed decrease in Hordeum shoot growth after infection were related to strongly elevated supply of nitrogen and phosphorus in the parasite and to incipient deficiency of these nutrients in the parasitised host. The flows of nutrients between host and parasite are discussed in terms of low selectivity of nutrient abstraction from the host xylem by the hemiparasite Rhinanthus minor.
Gradients in stomatal conductance, xylem sap ABA and bulk leaf ABA along canes of Vitis vinifera cv. Shiraz: molecular and physiological studies investigating their source
Authors: Soar Christopher J. , Speirs Jim , Maffei Suzanne M. , Loveys Brian R.
Published: June 2004

Gradients were observed in xylem sap ABA and in stomatal conductance along canes of Vitis vinifera L. cv. Shiraz. To investigate the source of the ABA responsible for these gradients a series of girdling and decapitation experiments were carried out. Leaf stomatal conductance and bulk ABA of leaves and apices were measured in control plants and in response to apex removal or girdling. Gradients in leaf ABA were observed over the first eight expanded leaves of field-grown Shiraz, with higher concentrations of ABA observed towards the apex. Gradients in stomatal conductance that correlated negatively with the concentration of ABA in the leaf ([ABA]leaf) were also observed over the first eight leaves. No significant effect of decapitation was observed on either leaf ABA or stomatal conductance except for the leaf immediately below the apex where a transient increase in [ABA]leaf was observed after 24 h with no corresponding decrease in conductance. Girdling resulted in an increase in [ABA]leaf in leaves distal to the girdle without the corresponding effect on conductance. These effects were further studied at the level of gene activity. To facilitate this, gene sequences encoding two key enzymes involved in the biosynthetic pathway of ABA in grape, zeaxanthin epoxidase (Zep) and 9-cis-epoxycarotenoid dioxygenase (NCED), were isolated and characterised. The cDNA sequences were used as probes to measure the abundances of their respective mRNAs in the leaf and apical material. Levels of expression of one of the two genes encoding NCED, VvNCED1, reflected the gradients in [ABA]leaf in control vines, however treatment-induced changes in ABA were not always associated with corresponding changes in VvNCED1 expression. The abundances of both the VvNCED2 mRNA and Zep mRNA increased with increasing leaf age and did not appear to be associated with either the [ABA]leaf or the expression of VvNCED1. Our results indicate that observed gradients in g s are correlated with [ABA] gradients in mature leaves and xylem sap and that these [ABA] gradients are not derived directly from the apical tissues but, at least partially, from local synthesis.
2-Phenylethylisothiocyanate concentration and bacterial community composition in the rhizosphere of field-grown canola
Authors: Rumberger Angelika , Marschner Petra
Published: June 2004

Field experiments with two spring and two winter canola cultivars were conducted in two successive years to study the release of 2-phenylethylisothiocyanate (PEITC) by living canola roots during plant development. The PEITC concentration in the rhizosphere of living roots ranged between 0 and 12 119 pmol g–1. Higher PEITC concentrations were detected in the first year in both spring and winter canola compared to the second year suggesting a strong impact of growth conditions on PEITC release. The PEITC concentration in the rhizosphere changed with plant development. In spring canola the PEITC concentration was highest at flowering. In winter canola the highest PEITC concentrations were found in autumn and in spring at booting. There were no differences in PEITC concentration in the rhizosphere between cultivars with high and low seed (winter canola) or root (spring canola) glucosinolate concentration. The rhizosphere bacterial community composition determined by denaturing gradient gel electrophoresis (DGGE) changed significantly with time. Some of the changes in bacterial rhizosphere community composition were correlated with the PEITC concentration in the rhizosphere. Other environmental factors such as plant dry matter and soil moisture also were significantly correlated with the bacterial community composition in the rhizosphere. It is concluded that PEITC can be released in sufficient amounts into the rhizosphere of living canola roots to be a selective factor for the bacterial community.
Effects of soil drying and subsequent re-watering on the activity of nitrate reductase in roots and leaves of Helianthus annuus
Authors: Azedo-Silva João , Osório Júlio , Fonseca Filomena , Correia Maria João
Published: June 2004

The effects of drought on the activity of nitrate reductase (NR) were studied in Helianthus annuus L. plants subjected to soil drying and subsequent re-watering. Drought did not negatively affect the activation state of NR, but resulted in linearly-correlated decreases in the activity of the unphosphorylated active form and the total activity of NR, in both roots and leaves. The concentration of nitrate in roots, xylem and leaves also decreased in water-stressed plants, whereas the concentration of total amino acids was only transiently depressed at the leaf level. In contrast, soluble sugars accumulated both in roots and leaves of water-stressed plants. Drought-induced decreases in root NR activity were correlated with the observed changes in root nitrate concentration. A higher percentage of the decrease in foliar NR activity could be explained by the decline in nitrate flux to the leaves than by leaf nitrate content. Following re-watering, the extent of recovery of NR activity was higher in roots than in leaves. The delay in the recovery of foliar NR activity did not result from the persistence of reduced flux of nitrate through the xylem. Several hypotheses to explain the after-effect of soil drying on foliar NR activity are discussed.
Interpretation of statolith microstructure in reared hatchling paralarvae of the squid Illex argentinus
Authors: Sakai Mitsuo , Brunetti Norma , Ivanovic Marcela , Elena Beatriz , Nakamura Kazuyoshi
Published: June 2004

To identify sub-daily or aperiodic increments of statolith growth in the ommastrephid squid Illex argentinus, we examined statolith microstructure, especially with regard to the natal ring, where counting of daily growth increments should begin, and the widths of subsequent daily increments. Paralarvae obtained by artificial fertilisation were incubated on board at different temperatures ranging from 11.4 to 25.4°C, and were starved throughout the experiments. We observed statolith growth from newly hatched to 10-day-old paralarvae and used alizarine complexone staining to attempt validation of the growth. The maximum statolith radius (MSR) of newly hatched paralarvae was constant at 21.1 μm across the full range of temperatures, with the exception of 25.4°C. Daily growth of MSR was analysed separately in two phases, the pre-yolk-absorption phase (i.e. yolk sac still present) and the post-yolk-absorption phase. During the pre-yolk-absorption phase, the daily growth rate (DGR, y) of the MSR varied from 3 to 7 μm day–1 depending on rearing temperature (x) and was expressed as y = 0.37x – 1.77. We concluded that the natal ring forms at 21 μm MSR. The initial increment width obtained from the DGR of MSR seems applicable for distinguishing daily rings from sub-daily rings, although this application should be limited to hatchling paralarvae in the pre-yolk-absorption phase.
The effect of variability in growth on somatic condition and reproductive status in the southern calamary Sepioteuthis australis
Authors: Ho J. D. , Moltschaniwskyj N. A. , Carter C. G.
Published: June 2004

The aim of the present study was to determine how the lifetime growth rates of adult southern calamary Sepioteuthis australis related to somatic and reproductive condition. A hierarchy of biological levels was explored: whole-animal, muscle fibre, and proximal condition. Evidence at all biological levels suggested that allocation of energy given to growth and reproduction was gender-specific. Females may not be allocating the same level of energy to somatic growth due to a greater requirement to re-allocate energy for reproductive growth. There was evidence that faster-growing males were in better somatic and reproductive condition. However, both males and females in better somatic condition were also in better reproductive condition. Fast growth rates by individuals were achieved primarily by muscle fibre growth, rather than production of new fibres. However, mantle muscle instantaneous growth rates (assessed through RNA : protein ratio) decreased as males became larger and more reproductively mature; no association was evident in females. An inverse correlation between gonad size and muscle instantaneous growth rates in females suggested energy was being directed away from somatic growth and towards reproductive growth. There was evidence that lifetime growth rates could predict the reproductive or somatic condition of adult calamary, but this was gender-specific.
Advances in defining the life histories of myopsid squid
Authors: Jackson George D.
Published: June 2004

Recent years have seen the emergence of extensive studies of myopsid squid growth of the family Loliginidae. This has greatly advanced our understanding of their life histories. Growth data have accumulated from both statolith-based field studies and culture work. Validation studies on loliginids continue to support that statolith increments are laid down daily. Ageing work has also revealed that short lifespans are typical, with nine of the 21 species studied having lifespans <200 days, eight species with lifespans between 200 days and about 1 year and only three species with lifespans >1 year. While growth is continuous and non-asymptotic, the marked plasticity in size-at-age has hindered the development of a general model to describe squid growth. Many loliginids are multiple spawners that continue to feed while growing and reproducing, although there has been some documented loss of conditon in mature individuals. An exception is Loligo opalescens, which has a terminal spawning strategy with a marked loss of condition and post-spawning mortality. Quantification of the cost of living and the energetics of loliginids are likely to be best achieved by combining field and culture studies on a species such as the Indo-Pacific squid Sepioteuthis lessoniana.
Energy balance as a determinant of two-phase growth in cephalopods
Authors: Grist Eric P. M. , Jackson George D.
Published: June 2004

Many cephalopods exhibit early exponential growth, which abruptly shifts to a much slower rate. Using a simple model of the energy balance between intake from food and expenditure in growth plus metabolism, we consider how the two-phase growth pattern may be explained in terms of energy conservation. We determine the post-hatch size and age at which exponential growth would be expected to terminate. The model is tested with laboratory hatchling data obtained for the giant Australian cuttlefish Sepia apama. Together with growth data obtained for a related species, Sepia officinalis, model projections for critical transition size and age interestingly suggest that the metabolism of S. apama in the natural habitat may be three to four times higher than in captivity. A sensitivity analysis indicates that the critical transition size is in general more sensitive than critical transition time to any invoked changes in metabolic rate.
Understanding octopus growth: patterns, variability and physiology
Authors: Semmens J. M. , Pecl G. T. , Villanueva R. , Jouffre D. , Sobrino I. , Wood J. B. , Rigby P. R.
Published: June 2004

Octopuses are generally characterised by rapid non-asymptotic growth, with high individual variability. However, in situ octopus growth is not well understood. The lack of an ageing method has resulted in the majority of our understanding of octopus growth coming from laboratory studies. Despite not being applicable to cephalopods, Modal Progression Analysis (MPA) of length–frequency data is the most common method for examining in situ octopus growth. Recently, counting growth increments in beaks and vestigial shells, and quantifying lipofuscin in brain tissue, have all shown promise for the ageing octopus. Octopuses generally demonstrate two-phase growth in the laboratory, with physiological changes possibly associated with the switch between an initial rapid exponential phase and a slower power growth phase. Temperature and food ration and quality are key factors influencing the initial growth phase. Temperature, however, does not appear to affect the second phase in any consistent way, perhaps because maturity stage can influence the growth response. There may be basic differences in the mechanisms of octopus muscle growth compared with that of other cephalopods. Furthermore, higher relative maintenance energy expenditure, along with the low energy content of their prey, may account for the relatively slow growth of deep-sea octopuses compared to littoral species.
Effects of genetic and environmental factors on growth of southern calamary, Sepioteuthis australis, from southern Australia and northern New Zealand
Authors: Triantafillos Lianos
Published: June 2004

Extreme plasticity in growth is consistently found by ageing studies on squid. This study examined the contribution that genetic and environmental factors had on growth of the southern calamary, Sepioteuthis australis, from sites in southern Western Australia, South Australia and New Zealand. A total of 147 adults, comprising three sympatric genetic types (two parental taxa and one hybrid), were aged by counting microincrements in statoliths. Estimates of age ranged from 121 to 268 days and varied with mantle length, sex, genetic type and region. Males grew much faster and attained a larger size than females. Significant differences were also detected between genetic types, with the hybrids always growing faster (at least 60% larger at 150 days old) than the two parental taxa, a phenomenon commonly referred to as hybrid vigour. Spatial differences in growth were also detected, with individuals from Western Australia usually growing faster than those from South Australia and New Zealand. Possible explanations for these growth patterns are discussed.
The isolation and characterisation of bacteria with the potential to degrade waxes that cause water repellency in sandy soils
Authors: Roper Margaret M.
Published: June 2004

Water repellency in soils is caused by waxy coatings on particles and can seriously limit agricultural production. Bioremediation of these soils, using wax-degrading bacteria isolated from soils and other sources rich in microorganisms, was investigated. Wool wax, a complex mixture of fatty acids and alcohols, was used to select bacteria capable of metabolising hydrophobic compounds. Of the 37 stable isolates, two-thirds were actinomycetes. These organisms are known for their ability to metabolise a wide range of organic compounds. Degradation of waxes associated with soil particles is facilitated by the production of biosurfactants that emulsify hydrophobic compounds. Measurement of biosurfactant production indicated that those isolates that grew best on hydrocarbon were also the most prolific biosurfactant producers. Inoculation of water-repellent soils, under controlled conditions, with the most efficient wax-degrading bacterial isolates resulted in significant improvements in soil wettability.
Loss of chondroitin 6-O-sulfotransferase-1 function results in severe human chondrodysplasia with progressive spinal involvement
Authors: Thiele Holger , Sakano Masahiro , Kitagawa Hiroshi , Sugahara Kazuyuki , Rajab Anna , Höhne Wolfgang , Ritter Heide , Leschik Gundula , Nürnberg Peter , Mundlos Stefan
Published: June 2004

We studied two large consanguineous families from Oman with a distinct form of spondyloepiphyseal dysplasia (SED Omani type). By using a genome-wide linkage approach, we were able to map the underlying gene to a 4.5-centimorgan interval on chromosome 10q23. We sequenced candidate genes from the region and identified a missense mutation in the chondroitin 6-O-sulfotransferase (C6ST-1) gene (CHST3) changing an arginine into a glutamine (R304Q) in the well conserved 3′-phosphoadenosine 5′-phosphosulfate binding site. C6ST-1 catalyzes the modifying step of chondroitin sulfate (CS) synthesis by transferring sulfate to the C-6 position of theN-acetylgalactosamine of chondroitin. From the crystal structures of other sulfotransferases, it could be inferred that Arg-304 is essential for the structure of the cosubstrate binding site. We used recombinant C6ST-1 to show that the identified missense mutation completely abolishes C6ST-1 activity. Disaccharide composition analysis of CS chains by anion-exchange HPLC shows that both ΔHexA-GalNAc(6S) and ΔHexA(2S)-GalNAc(6S) were significantly reduced in the patient's cells and that ΔHexA-GalNAc(4S,6S), undetectable in controls, was elevated. Analysis of the patient's urine shows marked undersulfation of CS, in particular reduction in 6-O-sulfated disaccharide and an increase in the nonsulfated unit. Our results indicate that the mutation in CHST3 described here causes a specific but generalized defect of CS chain sulfation resulting in chondrodysplasia with major involvement of the spine.
EFFECT OF VARIOUS AGENTS ON THE BLOOD FLOW THROUGH THE CORONARY ARTERIES AND VEINS
Authors: Bond G. S.
Published: June 2004

The results obtained show that adrenalin, transfusion with salt solution, and the inhalation of tobacco smoke caused an increased circulation in the coronary vessels. Amyl nitrite and nitroglycerin produce the opposite effect. Digitalis, strophanthus, caffeine, and theobromine give no change in the velocity of circulation.

We can conclude from the results that the blood pressure is the main element which influences coronary circulation, while the other factors play only a minor part in its variations.
THE EFFECT OF VAGUS SECTION UPON ANAPHYLAXIS IN GUINEA PIGS
Authors: Auer John
Published: June 2004

Depriving the bronchial muscles of one side of the lungs of their motor innervation does not interfere with sensitization nor the production of the typical anaphylactic lung. There is, therefore, direct sensitization of the muscle substance.

Complete degeneration of the vagus nerve, after sensitization has occurred, interferes in no appreciable way with the course of immediate anaphylaxis.

Partial degeneration of the vagus nerve, so that the bronchodilator fibers are still physiologically active, after sensitization has taken place, exerts no effect on the symptoms and lung picture of immediate anaphylaxis (very acute anaphylaxis with death after some minutes).

No definite evidence was obtained regarding the function of the motor nerve endings in the bronchial muscles in anaphylaxis.

The two sides of the lungs in immediate anaphylaxis may occasionally be unequal; when this occurs, the left side, especially the lower lobe, is usually fuller than the right side.
A TRANSMISSIBLE AVIAN NEOPLASM. (SARCOMA OF THE COMMON FOWL.)
Authors: Rous Peyton
Published: June 2004

In this paper is reported the first avian tumor that has proved transplantable to other individuals. It is a spindle-celled sarcoma of the hen, which thus far has been propagated into its fourth tumor generation. This was accomplished by the use of fowls of pure blood from the small, intimately related stock in which the growth occurred. Market-bought fowls of similar variety have shown themselves insusceptible, as have fowls of mixed breed, pigeons and guinea-pigs. The percentage of successful transplantations has been small, but in the individuals developing a tumor its growth has been fairly rapid. Young chickens are more susceptible than adults. The reinoculation of negative fowls has never resulted in a growth.

Throughout, the sarcoma has remained true to type. It is infiltrative and destructive. Metastasis has been observed once (to the heart). Experiments to determine whether the growth may be transmitted by cell-fragments have not yet been made. Repeated bacteriological examinations have yielded negative results.

In its general behavior, so far as tested, this avian tumor closely resembles the typical mammalian neoplasms that are transplantable.
Studies of thymocytopoiesis in rats and mice. I. Kinetics of appearance of thymocytes using a direct intrathymic adoptive transfer assay for thymocyte precursors.
Authors: Goldschneider I , Komschlies K L , Greiner D L
Published: June 2004

We describe a quantitative intrathymic (i.t.) adoptive transfer system for detecting thymocyte precursor cells in rats and mice. In this system, the generation of donor-origin thymocytes is analyzed on the FACS after the injection of test cells directly into the thymus of sublethally irradiated, histocompatible, RT-7 (rat) or Ly-1 (mouse) alloantigen-disparate recipients. Like the standard i.v. adoptive transfer assays for prothymocytes, the i.t. transfer assay is time, dose, and irradiation dependent. However, unlike the i.v. assays, the i.t. assay is highly sensitive, independent of cell migration, and specific for T-lineage precursor cells. Thus, the i.t. system requires between 25- and 50-fold fewer precursor cells than do the i.v. systems to generate a given number of donor-origin thymocytes; it detects nonmigratory as well as migratory subsets of precursor cells; it detects prethymic and intrathymic precursor cells with equal facility; and it produces a discrete, self-limited wave of donor-origin thymocytes and peripheral T cells. Moreover, neither hemopoietic nor lymphopoietic stem cell chimerism occurs at extrathymic sites. Comparison of the kinetics of thymocytopoiesis in the i.t. and i.v. transfer systems suggest that the seeding efficiency of prothymocytes in the i.v. assay approximates 0.04; the lag phase of the time-response curve is not due to a delay in the entry of prothymocytes into the thymus; and the relative amount of thymocyte precursor activity in various lymphohemopoietic tissues is highest in bone marrow, lowest (or absent) in lymph node, and intermediate in spleen, blood, and thymus. Moreover, the occurrence of saturation kinetics in the dose-response curve of the i.t. system supports the hypothesis that a finite number of microenvironmental niches for prothymocytes may exist in the thymus. These initial observations will require confirmation and extension in future studies. However, based on the present findings and related observations, we anticipate that the i.t. adoptive transfer system will contribute importantly to the definitive analysis of both normal and abnormal thymocytopoiesis.