Showing papers by "Cooperative Research Centre published in 1993"

Photoinhibition and D1 Protein Degradation in Peas Acclimated to Different Growth Irradiances

Abstract: The relationship between the susceptibility of photosystem II (PSII) to photoinhibition in vivo and the rate of degradation of the D1 protein of the PSII reaction center heterodimer was investigated in leaves from pea plants (Pisum sativum L. cv Greenfeast) grown under widely contrasting irradiances. There was an inverse linear relationship between the extent of photoinhibition and chlorophyll (Chl) a/b ratios, with low-light leaves being more susceptible to high light. In the presence of the chloroplast-encoded protein synthesis inhibitor lincomycin, the differential sensitivity of the various light-acclimated pea leaves to photoinhibition was largely removed, demonstrating the importance of D1 protein turnover as the most crucial mechanism to protect against photoinhibition. In the differently light-acclimated pea leaves, the rate of D1 protein degradation (measured from [35S]methionine pulse-chase experiments) increased with increasing incident light intensities only if the light was not high enough to cause photoinhibition in vivo. Under moderate illumination, the rate constant for D1 protein degradation corresponded to the rate constant for photoinhibition in the presence of lincomycin, demonstrating a balance between photodamage to D1 protein and subsequent recovery, via D1 protein degradation, de novo synthesis of precursor D1 protein, and reassembly of functional PSII. In marked contrast, in light sufficiently high to cause photoinhibition in vivo, the rate of D1 protein degradation no longer increased concomitantly with increasing photoinhibition, suggesting that the rate of D1 protein degradation is playing a regulatory role. The extent of thylakoid stacking, indicated by the Chl a/b ratios of the differently light-acclimated pea leaves, was linearly related to the half-life of the D1 protein in strong light. We conclude that photoinhibition in vivo occurs under conditions in which the rate of D1 protein degradation can no longer be enhanced to rapidly remove irreversibly damaged D1 protein. We suggest that low-light pea leaves, with more stacked membranes and less stroma-exposed thylakoids, are more susceptible to photoinhibition in vivo mainly due to their slower rate of D1 protein degradation under sustained high light and their slower repair cycle of the photodamaged PSII centers.

Random amplified polymorphic DNA markers reveal a high degree of genetic diversity in the entomopathogenic fungus Metarhizium anisopliae var. anisopliae

Abstract: Metarhizium anisopliae isolates from several insect hosts and from various sugar cane growing areas of Queensland, Australia, were examined for genetic diversity using random amplified polymorphic DNA (RAPD) markers. Thirty isolates of M. anisopliae var. anisopliae and one isolate of M. anisopliae var. majus were examined. Ten randomly chosen 10mer or 11mer primers were used and RAPD banding patterns were compared. Thirty distinct genotypes could be distinguished amongst the 31 isolates tested on the basis of RAPD patterns. Six of the isolates classified as M. anisopliae var. anisopliae exhibited closer similarity to the M. anisopliae var. majus isolate than to other anisopliae strains tested. Isolates exhibiting similar (> 80% similarity) RAPD profiles tended to be isolated from the same geographic area and evidence for the persistence of particular fungal genotypes in specific geographical localities was obtained. Pathogenicity assays suggested that, in some instances, RAPD groupings may also indicate insect host range. The mean similarity amongst isolates measured by band sharing in all pairwise comparisons was 41% and the most distinct pair of isolates shared only 9% of their RAPD bands. We conclude that the isolates tested belonging to the species M. anisopliae, as assessed on morphological grounds, represent a very diverse genetic group. The results also suggest that RAPD markers may be useful for the tracking of specific biocontrol strains in the field.

Insulin-like growth factor (IGF)-II binding to IGF-binding proteins and IGF receptors is modified by deletion of the N-terminal hexapeptide or substitution of arginine for glutamate-6 in IGF-II.

Abstract: Recombinant insulin-like growth factor-II (IGF-II) and two structural analogues, des(1-6)IGF-II and [Arg6]-IGF-II, were produced to investigate the role of N-terminal residues in binding to IGF-binding proteins (IGFBPs) and hence the biological properties of the modified peptides. The growth factors were modelled on two previously characterized variants of IGF-I, des(1-3)IGF-I and [Arg3]-IGF-I, which both show substantially decreased binding to IGFBPs and were expressed as fusion proteins in Escherichia coli. The biological activities of the corresponding analogues of IGF-I and IGF-II were compared in rat L6 myoblasts and H35B hepatoma cells. In the L6-myoblast protein-synthesis assay, the IGF-II analogues, des(1-6)IGF-II and [Arg6]-IGF-II, were slightly more potent than IGF-II but about 10-fold less potent than IGF-I and 100-fold less potent than the respective IGF-I analogues, des(1-3)IGF-I and [Arg3]IGF-I. In H35 hepatoma cells the anabolic response measured was the inhibition of protein breakdown, and the potency order was insulin >>> [Arg3]-IGF-I > des(1-3)IGF-I > [Arg6]-IGF-II > des(1-6)IGF-II > IGF-I > IGF-II. Binding of the IGFs and their analogues to the type 1 IGF receptor in L6 myoblasts and to the insulin receptor in H35 hepatoma cells did not fully explain the observed anabolic potency differences. Moreover, binding of all four analogues to the IGFBPs secreted by L6 myoblasts and H35B hepatoma cells was greatly decreased compared with the parent IGF. We conclude that the observed anabolic response to each IGF was determined by their relative binding to the competing cell receptor and IGFBP binding sites present.

Improving the efficiency of water use by plant breeding and molecular biology

Abstract: Plant breeding over the last century has indirectly increased water use efficiency of the major grain crops because yield has increased with no additional water use. These increases have been substantial in all major food crops. Improved varieties have come from conventional breeding programs where selection has been for yield. Although these increases are likely to continue, they may not occur at the same rate as before. Most of the increases have been due to improvements in harvest index which must now be approaching its theoretical limit in many of our major crops. There has been little increase in water use efficiency for biomass and this must be increased if improvements in water-use efficiency are to continue. Possibilities are numerous. They will depend on the crop and the environment in which it is grown. Modification of phenology to better suit the environment, which has been responsible for many of the increases in the past, will continue to be important in most crops. Genetic increases in water-use efficiency should also come from the manipulation of the crop canopy to reduce wasteful evaporation of water from the soil surface and from an improvement in transpiration efficiency. The most likely avenues for success are discussed.

Anabolic effects of insulin-like growth factor-I (IGF-I) and an IGF-I variant in normal female rats

Abstract: Administration of IGF-I over a 14-day period to growing female rats via s.c. implanted osmotic pumps led to an increased body weight gain, an improved N retention and a greater food conversion efficiency. The effects were dose-dependent, with the highest daily dose tested, 278 micrograms/day, producing 18-26% increases in these measurements. LR3IGF-I, a variant of human IGF-I that contains an amino terminal extension peptide as well as glutamate-3 replaced by arginine and exhibits very weak binding to IGF-binding proteins, was substantially more potent than the natural growth factor, in the 44 micrograms/day of this peptide produced similar effects to the high IGF-I dose. Organ weight and carcass composition measurements showed that the two IGF peptides generally maintained body proportions at those existing when the experiment began. Muscle protein synthesis and myofibrillar protein breakdown were both slightly increased by IGF treatment, so that the observed improvement in N retention could not be explained through protein accretion rates calculated from these measures. Infusion of human GH at a dose of 213 micrograms/day did not stimulate body growth. This investigation establishes that IGF peptides stimulate the growth of normal growing animals, with IGF-I variants that bind less well to IGF-binding proteins being more active than IGF-I.

Biological control of take-all of glasshouse-grown wheat using strains of pseudomonas corrugata isolated from wheat field soil

Abstract: Bacteria were isolated from the rhizospheres of wheat plants. Selected bacterial isolates, some inhibitory and some non-inhibitory in vitro to Gaeumannmyces graminis var. tritici (Ggt), were tested for their ability to control take-all on wheat in a pot assay. The isolates were assayed in a natural (non-sterilized) soil-sand mixture with added Ggt inoculum. A group of non-fluorescent Pseudomonas isolates gave significant and reproducible disease suppression. One of these isolates stimulated plant growth in the absence of disease, though this effect was not consistent. The non-fluorescent isolates were identified as most closely related to Pseudomonas corrugata. Strain 2140 of Pseudomonas corrugata controlled take-all in vivo at 15°C and inhibited the growth of Ggt in vitro in the range 10–25°C.

Yield prediction models and comparative growth rates for six eucalypt species

Abstract: Summary Stand stem volume yield prediction models are presented for six eucalypt species Eucalyptus regnans F. Muell., E. obliqua L'Her., E. delegatensis R. Baker. E. pilularis Smith, E. grandis Hill ex Maiden and E. diversicolor F. Muell. The data set used was collected over many years by eight of the major forestry agencies of Australia. It included data only from fully stocked, monospecific stands which had received no major natural or unnatural disturbance throughout their life-times. The bulk of the data was collected from regrowth forest, but some data from plantation forest were also included. The data did not sample formally or fully the entire area of natural occurrence of the six species. These data limitations must be borne in mind when applying the models. A site-index equation is developed for each species and these are then used in developing the stand stem volume yield prediction models which were based on the commonly used Schumacher model. The models are then used to compare growth rates ...

Stored xylem sap from wheat and barley in drying soil contains a transpiration inhibitor with a large molecular size

Abstract: Xylem sap was collected from wheat and barley growing in a drying soil, and the effect of the sap on transpiration was detected by a bioassay with detached wheat leaves. The inhibitory activity of fresh sap was small, and could be largely accounted for by the abscisic acid content (about 2×10-5mol m-3). When fresh sap was stored at -20°C for several days, the activity increased. Maximum activity developed after a week. This increase in activity was due to a compound that increased in size with storage at -20°C. When fresh sap was fractionated with filters of different molecular size exclusion characteristics, and the separated fractions stored at -20°C for a week, activity developed only in the fraction containing compounds smaller than 0·3 kDa. However, when sap already stored at -20°C was fractionated, activity was only in fractions containing compounds larger than 0·3 kDa. The increase in activity and in size did not occur with storage in liquid nitrogen (-196°C) or at -80°C. These results suggest that storage at -20°C causes the aggregation or polymerization of a small compound with low activity to form a large compound with high activity. This change is not catalysed by an enzyme because it can occur in a fraction from which molecules larger than 0·3 kDa are removed. It is probably promoted by high solute concentrations when ice crystals form. Sap collected from plants in soils of high water potential had little or no activity after storage at -20°C.

The relative significance for stem elongation and flowering in Lolium temulentum of 3β-hydroxylation of gibberellins

Abstract: In previous experiments with many gibberellins (GAs) and GA derivatives applied to Lolium temulentum L, quite different structural requirements were evident for stem elongation on the one hand and for the promotion of flowering on the other Whereas hydroxylation at carbons 12, 13 and 15 enhanced flowering relative to stem growth, the reverse was the case at carbon 3 (LT Evans et al 1990, Planta 182, 97–106) The significance of hydroxylation at carbon 3 is examined in this paper The application of inhibitors of 3β-hydroxylation, including C/D-ring-rearranged GAs, reduced stem growth but, in the case of the two acylcyclohexanediones, increased the flowering response when applied on the inductive long day Later applications of the acylcyclohexanediones, made after floral initiation had occurred, were inhibitory to flowering, suggesting that subsequent inflorescence development requires 3β-hydroxylated GAs Applications of the 3α-hydroxy epimers of GA1, GA3 and GA4 gave slightly less promotion of flowering in comparison with the 3β-hydroxy GAs, but far less promotion of stem elongation, except in the case of 3-epi-GA4, which was comparable to GA4 The 3α-hydroxy epimer of 2,2-dimethyl GA4 gave less promotion of flowering than its 3β-hydroxy epimer but almost no promotion of stem elongation The 3α-hydroxy epimers of GA3 and 2,2-dimethyl GA4 did not act as competitive inhibitors of the stem elongation elicited by GA3 and 2,2-dimethyl GA4, respectively These results extend the differences in GA structure which favour flowering as opposed to stem elongation, and indicate that 3-hydroxylation and its epimeric configuration are of much greater importance to stem elongation than to flower initiation in Lolium

Reduced severity of rhizoctonia solani disease on wheat seedlings associated with the presence of the earthworm aporrectodea trapezoides (lumbricidae)

Abstract: The influence of the earthworm Aporrectodea trapezoides on wheat plants grown in a calcareous sand loam and a red-brown earth soil, artificially infested with Rhizoctonia solani , was examined. Presence of the earthworm A. trapezoides , at a number equivalent to 471 m −2 was associated with a significant increase in shoot weight and a reduction in the root disease rating of wheat in both soil types artificially infested with R. solani on wheat chaff. In both soil types, the shoot weight of wheat grown in the presence of A. trapezoides and R. solani was equivalent to that of wheat grown in the absence of R. solani. One further treatment was applied to each soil type. In the calcareous sand inoculated with R. solani on wheat chaff, A. trapezoides was as effective as mechanical soil disturbance in reducing the root disease rating on wheat. In the red brown earth, in which R. solani was introduced via naturally infected roots, the presence of A. trapezoides was associated with a significant increase in shoot weight and a reduction in the root disease rating of wheat. These results demonstrate the potential of the earthworm A. trapezoides to reduce the effect of Rhizoctonia root rot on wheat.

Evolution of insulin-like growth factor binding proteins.

Abstract: In order to understand more about the origins and evolutionary relationships of insulin-like growth factors (IGFs) and their binding proteins (IGFBPs) we have commenced characterization of the IGFBPs in non-mammalian sera. We show by both in vitro labelling with subsequent analytical gel filtration and by ligand blotting that IGFBPs are present in lamprey serum, indicating that the IGFBPs are indeed, very ancient proteins. Furthermore we present evidence that the major serum IGFBP in lamprey is significantly smaller than the high molecular weight IGFBP3 complex in rat serum. In addition, we show that IGFBPs occur widely throughout vertebrates as we detect IGFBPs in ligand blots of serum from marsupials, monotremes, reptiles, birds and turtles.

Influence of the lumbricid earthworm Aporrectodea trapezoides on the colonization of wheat roots by Pseudomonas corrugata strain 2140R in soil

Abstract: In a greenhouse study, the ability of the earthworm Aporrectodea trapezoides to transport Pseudomonas corrugata strain 2140R (which acts as a biocontrol agent against Gaeumannomyces graminis var. tritici) in soil was examined. When the bacterium was inoculated into Ezi-mulch (a pelleted formulation of cereal-pea straw) and placed on the soil surface, after 9 days > 104 cfu strain 2140R g−1' soil were detected at 9 cm soil depth in the presence of A. trapezoides, but none were detected in the absence of A. trapezoides. In a second experiment, the presence of A. trapezoides was associated with increased wheat root colonization by 2140R, when the bacteria were inoculated into Ezi-mulch and placed on the soil surface or when the bacteria were inoculated onto wheat seeds prior to sowing. These results demonstrate the potential of A. trapezoides to increase the movement and root colonization of wheat by P. corrugata strain 2140R in soil.

Green icebergs formed by freezing of organic-rich seawater to the base of Antarctic ice shelves

Abstract: Samples of Antarctic seawater, basal ice, and green ice from ice cliffs and green icebergs are analyzed in order to examine green icebergs formed by the freezing of organic-rich seawater to the base of Antarctic ice shelves. Spectral reflectance of a green iceberg measured near 67 deg S, 62 deg E confirms that the color is inherent in the ice, not an artifact of the illumination. A constituent that absorbs blue photons is identified by spectrophotometric analysis of core samples from this iceberg and from the Amery basal ice, and of seawater samples from Prydz Bay off the Amery Ice Shelf. Analysis of the samples by fluorescence spectroscopy indicates that the blue absorption, and hence the inherent green color, is due to the presence of marine-derived organic matter in the green iceberg, basal ice, and seawater. Thick accumulations of green ice, in icebergs, and at the base of ice shelves indicate that high concentrations of organic matter exist in seawater for centuries at the depth of basal freezing.

Effects of interactions between IGFBPs and IGFs on the plasma clearance and in vivo biological activities of IGFs and IGF analogs.

Abstract: The relative activities in vivo of IGFs that differ in their association affinities towards IGF binding proteins (IGFBPs) have been examined in a series of comparisons between IGF-I and LR3IGF-I. IGF-I has approximately 1000 fold higher affinity than LR3IGF-I towards IGFBP-3, IGFBP-4, total rat plasma IGFBPs and L6 myoblast BP. In cultured L6 myoblasts the reduced association with IGFBPs gives LR3IGF-I a 5-10 fold greater biological potency. Chronic administration of the peptides over 14 days to normal female rats produces marked increases in body weight, nitrogen retention and food conversion efficiency as well as retention of the carcass composition and fractional weights of the gut, spleen and thymus that are characteristic of the younger age. In the growth measurements LR3IGF-I is 6 fold more potent than IGF-I, thus reflecting the in vitro difference. In a second series of experiments in which the clearance rates of the two peptides were compared, LR3IGF-I was shown to be removed from the plasma much more rapidly than was IGF-I, a difference reflecting the poor association of LR3IGF-I with plasma IGFBPs. The crucial relevance of binding protein association in explaining the difference was confirmed in pregnant rats where IGFBP levels are markedly reduced. In this condition only the clearance of IGF-I was affected to produce a clearance rate almost as rapid as that found with LR3IGF-I. These experiments demonstrate that an IGF variant which associates poorly with IGFBPs is removed more rapidly from the blood and is more potent than IGF-I.

Instability of the L6 gene for rust resistance in flax is correlated with the presence of a linked Ac element

Abstract: In a programme aimed at tagging rust-resistance genes in flax with the maize transposable element Ac, a primary transformant of a line called 'Forge' that is homozygous for four rust-resistance genes, L6, M, N and P2, was identified that possessed 10 copies of the Ac element, one of which was linked (29 map units) to L6. Descendants of this plant, which had from 8 to 15 copies of Ac, were crossed to a rust-susceptible line and the progeny screened for rust-susceptible mutants. When the Ac linked to L6 was present in the parent, a high frequency of L6 mutants was observed (29 mutants in 30,575). By contrast, when this Ac was absent, no such mutants were observed in 9258 progeny. The background frequency of L6 mutants was low (five in 124,088). A detailed analysis was made of the first 11 L6 mutants recovered from parents carrying the L6-linked Ac element. While none of the mutants possessed a tagged resistance gene, all lacked an RFLP marker closely linked to L6, suggesting that deletions were responsible for loss of the L6 specificity. In many of the mutants, one or more RFLP markers in the vicinity of the linked Ac were also absent. These findings suggest that the linked Ac may be inducing chromosome breakage.

The estimation of the shape of an array using a hidden Markov model

Abstract: A hidden Markov model (HMM) technique for the estimation of the shape of a towed array is presented. It is assumed that there is a far-field source radiating sound containing possibly weak spectral lines. The technique uses either the Fourier coefficients at a given frequency computed from a single time block or the maximal eigenvector of a sample spectral covariance matrix. The technique is illustrated using several simulations. The results of these simulations indicate that the HMM technique yields shape and bearing estimates more accurate than those provided by a maximum-likelihood array shape estimation technique. >

Insulin-like growth factor-I and more potent variants restore growth of diabetic rats without inducing all characteristic insulin effects

Abstract: The effects of graded doses of insulin-like growth factor-I (IGF-I) and two variants which bind poorly to IGF-binding proteins were investigated in 160 g streptozotocin-induced diabetic rats. The two variants were the truncated form, des(1-3)IGF-I, and another with arginine at residue 3 and an N-terminal extension, termed LR3-IGF-I. The peptides were infused via mini-osmotic pumps. Reference groups received either vehicle or insulin (30 i.u. per day). Treatment led to a marked dose-dependent increase in growth rate and nitrogen balance. The highest dose (695 micrograms/day) of IGF-I increased body weight by 48.1 +/- 1.7 g/7 days, compared with 11.0 +/- 2.8 g/7 days for the vehicle-treated group. The two variants were 2.5-3 times more potent than IGF-I in restoring growth. The insulin-treated group gained more weight (64.5 +/- 1.6 g/7 days), but the added gain was fat (92.5 +/- 4.8 g of fat/kg carcass wet wt., compared with 32.2 +/- 2.1 for all other groups) rather than protein. All peptides increased muscle protein-synthesis rates and RNA levels by up to 50%, with IGF-I the least potent. These high doses of IGFs did not decrease either the glucosuria or the daily excretion rate of N tau-methyl-histidine (N tau-MH). On the other hand, insulin treatment markedly decreased both glucosuria (from 82.7 +/- 5.4 to 4.5 +/- 3.3 mmol/day) and N tau-MH excretion (from 9.3 +/- 0.3 to 7.1 +/- 0.4 mumol/day per kg). This experiment shows that, although IGF-I and variants can restore growth in diabetic rats, other insulin-dependent metabolic processes in liver, muscle and adipose tissue are not restored.

The phylogeny of bacteria from a modern Antarctic refuge

Abstract: The 16S rRNAs of nine new species of prokaryotes, that had been isolated from four lakes of the Vestfold Hills, have been sequenced. These sequences were compared with those of their closest taxonomic relatives available from publicly available databases. The Antarctic species were of wide diversity with representatives from the domains Archaea and Bacteria (sensu Woese). Generally, they were most closely related to organisms from marine environments. The sequence dissimilarity between the rRNA sequences of the Antarctic strains and their nearest known relatives suggest they diverged from each other much earlier than the establishment of their modern Antarctic habitat

Light quality during growth of Tradescantia albiflora regulates photosystem stoichiometry, photosynthetic function and susceptibility to photoinhibition

Abstract: Trandescantia albiflora (Kunth) was grown under two different light quality regimes of comparable light quantity: in red + far-red light absorbed mainly by photosystem I(PSI light) and yellow light absorbed mainly by photosystem II (PSII light). The composition, function and ultrastructure of chloroplasts, and photoinhibition of photosynthesis in the two types of leaves were compared. In contrast to regulation by light quantity (Chow et al. 1991. Physiol. Plant. 81: 175-182), light quality exerted an effect on the composition of pigment complexes, function and structure of chloroplasts in Tradescantia: PSII light-grown leaves had higher Chi a/b ratios, higher PSI concentrations, lower PSII/PSI reaction centre ratios and less extensive thylakoid stacking than PSI light-grown leaves. Light quality triggered modulations of chloroplast components, leading to a variation of photosynthetic characteristics. A larger proportion of primary quinone acceptor (Q(A)) in PSI light-grown leaves was chemically reduced at any given irradiance. It was also observed that the quantum yield of PSII photochemistry was lower in PSI light-grown leaves. PSI light-grown leaves were more sensitive to photoinihibition and recovery was slower compared to PSII light-grown leaves, showing that the PSII reaction centre in PSI light-grown leaves was more easily impaired by photoinhibition. The increase in susceptibility of leaves to photoinhibition following blockage of chloroplast-encoded protein synthesis was greater in PSII light-grown leaves, showing that these leaves normally have a greater capacity for PSII repair. Inhibition of zeaxanthin formation by dithiothreitol slightly increased sensitivity to photoinhibition in both PSI and PSII light-grown leaves.

Biology and biotechnological potential of halotolerant bacteria from Antarctic saline lakes

Abstract: The saline lakes of the Vestfold Hills, Antarctica, are unique ecosystems in which microorganisms survive and grow in cold, saline and often anaerobic conditions. A polyphasic approach to taxonomy of the microbiota has extended the known range of microbial diversity through description of nine new species including bacteria and archaea. Low temperature and reduced water activity are the major constraints on microbial growth in the lakes. Bělhradek-type models provide a good description of temperature dependence and indicate the potential of the microbiota to colonise their natural habitats. Physiological traits of the microbiota selected by the physical and chemical characteristics of the saline lakes suggest biotechnological potential in areas such as polyunsaturated fatty acid production and hydrocarbon degradation.

Some new performance considerations in open distributed environments

Abstract: Some novel issues relevant to emerging open distributed environments, of which a long term intelligent network (IN) architecture represents a telecommunication-specific example, are addressed. IN has the goal of supporting rapid introduction, modification, execution, and management of a broad range of multimedia information services and will build on advances in broadband technologies and open distributed processing. Emphasis is placed on the performance concerns and new quality of servicer requirements as a consequence of new technologies and market forces. The open distributed processing (ODP) trader component is selected to categorize the trader according to various characteristics depending on its possible operational environments. This enables the identification of various trader goals which could be achieved in part by attention to quality of service objectives. A universal publicly owned trader is studied, implementing an essentially social selection policy where an overall system delay is chosen as a performance measure having an impact on quality of service and hence overall enterprise goals. It is concluded that a minimum workload selection policy can produce acceptable system response times under assumptions of quite high delays in the provision of dynamic state information. >

Identification of the Key Odorous Component of an Olearia phlogopappa Clone

Abstract: A clone of the Australian endemic shrub Olearia phlogopappa Labill. D.C., collected from Mt. Wellington, produces a highly aromatic essential oil. Liguloxide has been shown to be the component responsible for the characteristic tomato ketchup note associated with this oil. In addition, kessane, bicyclogermacrene, germacrene-D, spathulenol and caryophyllene oxide were isolated by HPLC and characterized by 1H- and 13C-NMR spectroscopy.

Framework for Implementing the Next Generation of Communication Protocols

Abstract: Future distributed multimedia applications will require an architecture capable of managing Quality of Service end to end. This is not achievable using current, general purpose protocol stacks. We present a framework that will permit QoS management at all layers. It will support QoS negotiation, flexible configuration of protocols to match application requirements with network and system resources, QoS monitoring, renegotiation and reconfiguration. This paper focusses particularly on the protocol profiling and configuration aspects of the framework. Adaptive profiling requires understanding of transport protocol mechanism dependencies. This is illustrated by an example configuration suitable to continuous media applications.