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Showing papers by "University of Waterloo published in 2005"


Journal ArticleDOI
TL;DR: The new HITRAN is greatly extended in terms of accuracy, spectral coverage, additional absorption phenomena, added line-shape formalisms, and validity, and molecules, isotopologues, and perturbing gases have been added that address the issues of atmospheres beyond the Earth.
Abstract: This paper describes the contents of the 2016 edition of the HITRAN molecular spectroscopic compilation. The new edition replaces the previous HITRAN edition of 2012 and its updates during the intervening years. The HITRAN molecular absorption compilation is composed of five major components: the traditional line-by-line spectroscopic parameters required for high-resolution radiative-transfer codes, infrared absorption cross-sections for molecules not yet amenable to representation in a line-by-line form, collision-induced absorption data, aerosol indices of refraction, and general tables such as partition sums that apply globally to the data. The new HITRAN is greatly extended in terms of accuracy, spectral coverage, additional absorption phenomena, added line-shape formalisms, and validity. Moreover, molecules, isotopologues, and perturbing gases have been added that address the issues of atmospheres beyond the Earth. Of considerable note, experimental IR cross-sections for almost 300 additional molecules important in different areas of atmospheric science have been added to the database. The compilation can be accessed through www.hitran.org. Most of the HITRAN data have now been cast into an underlying relational database structure that offers many advantages over the long-standing sequential text-based structure. The new structure empowers the user in many ways. It enables the incorporation of an extended set of fundamental parameters per transition, sophisticated line-shape formalisms, easy user-defined output formats, and very convenient searching, filtering, and plotting of data. A powerful application programming interface making use of structured query language (SQL) features for higher-level applications of HITRAN is also provided.

7,638 citations


Journal ArticleDOI
TL;DR: It is argued that when it is easy to manipulate and measure a proposed psychological process that a series of experiments that demonstrates the proposed causal chain is superior, and that designs that examine underlying process by utilizing moderation can be effective.
Abstract: The authors propose that experiments that utilize mediational analyses as suggested by R. M. Baron and D. A. Kenny (1986) are overused and sometimes improperly held up as necessary for a good social psychological paper. The authors argue that when it is easy to manipulate and measure a proposed psychological process that a series of experiments that demonstrates the proposed causal chain is superior. They further argue that when it is easy to manipulate a proposed psychological process but difficult to measure it that designs that examine underlying process by utilizing moderation can be effective. It is only when measurement of a proposed psychological process is easy and manipulation of it is difficult that designs that rely on mediational analyses should be preferred, and even in these situations careful consideration should be given to the limiting factors of such designs.

1,812 citations


Proceedings ArticleDOI
28 Nov 2005
TL;DR: Opposition-based learning as a new scheme for machine intelligence is introduced and possibilities for extensions of existing learning algorithms are discussed.
Abstract: Opposition-based learning as a new scheme for machine intelligence is introduced. Estimates and counter-estimates, weights and opposite weights, and actions versus counter-actions are the foundation of this new approach. Examples are provided. Possibilities for extensions of existing learning algorithms are discussed. Preliminary results are provided

1,464 citations


Journal ArticleDOI
TL;DR: Comparisons among the formulation and results of five recent evolutionary-based algorithms: genetic algorithms, memetic algorithms, particle swarm, ant-colony systems, and shuffled frog leaping are compared.

1,268 citations


Proceedings ArticleDOI
14 Jun 2005
TL;DR: Analysis and comparison of EDR with other popular distance functions, such as Euclidean distance, Dynamic Time Warping (DTW), Edit distance with Real Penalty (ERP), and Longest Common Subsequences, indicate that EDR is more robust than Euclideans distance, DTW and ERP, and it is on average 50% more accurate than LCSS.
Abstract: An important consideration in similarity-based retrieval of moving object trajectories is the definition of a distance function. The existing distance functions are usually sensitive to noise, shifts and scaling of data that commonly occur due to sensor failures, errors in detection techniques, disturbance signals, and different sampling rates. Cleaning data to eliminate these is not always possible. In this paper, we introduce a novel distance function, Edit Distance on Real sequence (EDR) which is robust against these data imperfections. Analysis and comparison of EDR with other popular distance functions, such as Euclidean distance, Dynamic Time Warping (DTW), Edit distance with Real Penalty (ERP), and Longest Common Subsequences (LCSS), indicate that EDR is more robust than Euclidean distance, DTW and ERP, and it is on average 50% more accurate than LCSS. We also develop three pruning techniques to improve the retrieval efficiency of EDR and show that these techniques can be combined effectively in a search, increasing the pruning power significantly. The experimental results confirm the superior efficiency of the combined methods.

1,225 citations


Book
01 Jul 2005
TL;DR: This paper presents a meta-analyses of correlation in cyclic Hadamard sequences and its applications to radar, sonar, and synchronization, and describes the properties of correlation as well as applications to Boolean functions.
Abstract: This book provides a comprehensive description of the methodologies and the application areas, throughout the range of digital communication, in which individual signals and sets of signals with favorable correlation properties play a central role. The necessary mathematical background is presented to explain how these signals are generated, and to show how they satisfy the appropriate correlation constraints. All the known methods to obtain balanced binary sequences with two-valued autocorrelation, many of them only recently discovered, are presented in depth. The authors treat important application areas including: Code Division Multiple Access (CDMA) signals, such as those already in widespread use for cell-phone communication, and planned for universal adoption in the various approaches to 'third-generation'(3G) cell-phone use; systems for coded radar and sonar signals; communication signals to minimize mutual interference ('cross-talk') in multi-user environments; and pseudo-random sequence generation for secure authentication and for stream cipher cryptology.

872 citations


Journal ArticleDOI
TL;DR: A comprehensive review of the flow-field layouts developed by different companies and research groups and the pros and cons associated with these designs is presented in this article, where the authors also present a comprehensive analysis of the performance and economic advantages of these layouts.

816 citations


Journal ArticleDOI
TL;DR: The Atmospheric Chemistry Experiment (ACE) is a Canadian satellite mission for remote sensing of the Earth's atmosphere that was launched into low Earth circular orbit (altitude 650 km, inclination 74°) on 12 Aug. 2003.
Abstract: SCISAT-1, also known as the Atmospheric Chemistry Experiment (ACE), is a Canadian satellite mission for remote sensing of the Earth's atmosphere. It was launched into low Earth circular orbit (altitude 650 km, inclination 74°) on 12 Aug. 2003. The primary ACE instrument is a high spectral resolution (0.02 cm-1) Fourier Transform Spectrometer (FTS) operating from 2.2 to 13.3 μm (750-4400 cm-1). The satellite also features a dual spectrophotometer known as MAESTRO with wavelength coverage of 285-1030 nm and spectral resolution of 1-2 nm. A pair of filtered CMOS detector arrays records images of the Sun at 0.525 and 1.02 μm. Working primarily in solar occultation, the satellite provides altitude profile information (typically 10-100 km) for temperature, pressure, and the volume mixing ratios for several dozen molecules of atmospheric interest, as well as atmospheric extinction profiles over the latitudes 85°N to 85°S. This paper presents a mission overview and some of the first scientific results. Copyright 2005 by the American Geophysical Union.

807 citations


Journal ArticleDOI
TL;DR: Soil microorganisms that produce the enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase promote plant growth by sequestering and cleaving plant-produced ACC, and thereby lowering the level of ethylene in the plant.
Abstract: Soil microorganisms that produce the enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase promote plant growth by sequestering and cleaving plant-produced ACC, and thereby lowering the level of ethylene in the plant. Decreased ethylene levels allows the plant to be more resistant to a wide variety of environmental stresses. Here, the biochemistry of ACC deaminase; the environmental distribution, regulation, evolution and expression of ACC deaminase genes; and information regarding the effect of this enzyme on different plants is documented and discussed.

776 citations


Journal ArticleDOI
TL;DR: Various microbiological and enzymatic methods for synthesis of PUFAs are discussed and marine protists and dinoflagellates are the rich sources of DHA, whereas microalgae like Phaeodactylum and Monodus are good sources of EPA.

747 citations


Journal ArticleDOI
TL;DR: A positive correlation between the in vitro ACC deaminase activity of the bacteria and their stimulating effect on root elongation suggested that utilization of ACC is an important bacterial trait determining root growth promotion.
Abstract: Eleven cadmium-tolerant bacterial strains were isolated from the root zone of Indian mustard (Brassica juncea L. Czern.) seedlings grown in Cd-supplemented soils as well as sewage sludge and mining waste highly contaminated with Cd. The bacteria also showed increased tolerance to other metals including Zn, Cu, Ni and Co. The isolated strains included Variovorax paradoxus, Rhodococcus sp. and Flavobacterium sp., and were capable of stimulating root elongation of B. juncea seedlings either in the presence or absence of toxic Cd concentrations. Some of the strains produced indoles or siderophores, but none possessed C2H2-reduction activity. All the strains, except Flavobacterium sp. strain 5P-3, contained the enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase, which hydrolyses ACC (the immediate precursor of plant hormone ethylene) to NH3 and a-ketobutyrate. V. paradoxus utilized ACC as a sole source of N or energy. A positive correlation between the in vitro ACC deaminase activity of the bacteria and their stimulating effect on root elongation suggested that utilization of ACC is an important bacterial trait determining root growth promotion. The isolated bacteria offer promise as inoculants to improve growth of the metal accumulating plant B. juncea in the presence of toxic Cd concentrations and for the development of plantinoculant systems useful for phytoremediation of polluted soils. q 2004 Elsevier Ltd. All rights reserved.

Journal ArticleDOI
TL;DR: In this Letter, a new image encryption scheme is presented, in which shuffling the positions and changing the grey values of image pixels are combined to confuse the relationship between the cipher-image and the plain-image.

Journal ArticleDOI
TL;DR: It is argued that cardinality-based feature models can be interpreted as a special class of context-free grammars, and a semantic interpretation is provided by assigning an appropriate semantics to the language recognized by the corresponding grammar.
Abstract: Feature modeling is an important approach to capture the commonalities and variabilities in system families and product lines. Cardinality-based feature modeling integrates a number of existing extensions of the original feature-modeling notation from Feature-Oriented Domain Analysis. Staged configuration is a process that allows the incremental configuration of cardinality-based feature models. It can be achieved by performing a step-wise specialization of the feature model. In this article, we argue that cardinality-based feature models can be interpreted as a special class of context-free grammars. We make this precise by specifying a translation from a feature model into a context-free grammar. Consequently, we provide a semantic interpretation for cardinality-based feature models by assigning an appropriate semantics to the language recognized by the corresponding grammar. Finally, we give an account on how feature model specialization can be formalized as transformations on the grammar equivalent of feature models. Copyright © 2005 John Wiley & Sons, Ltd.

Book ChapterDOI
29 Sep 2005
TL;DR: This paper proposes a general template-based approach for mapping feature models to concise representations of variability in different kinds of other models and shows how it can be applied to UML 2.0 activity and class models.
Abstract: Although a feature model can represent commonalities and variabilities in a very concise taxonomic form, features in a feature model are merely symbols. Mapping features to other models, such as behavioral or data specifications, gives them semantics. In this paper, we propose a general template-based approach for mapping feature models to concise representations of variability in different kinds of other models. We show how the approach can be applied to UML 2.0 activity and class models and describe a prototype implementation.

Journal ArticleDOI
TL;DR: Exposing participants to gender-stereotypic TV commercials designed to elicit the female stereotype explored whether vulnerability to stereotype threat could persuade women to avoid leadership roles in favor of nonthreatening subordinate roles.
Abstract: Exposing participants to gender-stereotypic TV commercials designed to elicit the female stereotype, the present research explored whether vulnerability to stereotype threat could persuade women to avoid leadership roles in favor of nonthreatening subordinate roles. Study 1 confirmed that exposure to the stereotypic commercials undermined women's aspirations on a subsequent leadership task. Study 2 established that varying the identity safety of the leadership task moderated whether activation of the female stereotype mediated the effect of the commercials on women's aspirations. Creating an identity-safe environment eliminated vulnerability to stereotype threat despite exposure to threatening situational cues that primed stigmatized social identities and their corresponding stereotypes.

Journal ArticleDOI
TL;DR: The response to a stabilization exercise program in patients with LBP can be predicted from variables collected from the clinical examination, and the prediction rules could be used to determine whether patients with low back pain are likely to benefit from stabilization exercises.

Journal ArticleDOI
TL;DR: In this article, the authors examine and elaborate on the central elements of sustainable development and governance, considering their interrelations as they have emerged from the core themes in sustainable development discourses over the past decade and a half.
Abstract: In this paper we examine and elaborate on the central elements of sustainable development and governance, considering their interrelations as they have emerged from the core themes in sustainable development discourses over the past decade and a half. We argue that sustainability is best viewed as a socially instituted process of adaptive change in which innovation is a necessary element. We discuss four key elements of governance for sustainability, which are integrated into the concept of transition management. The result is a conceptual framework for policy-making and action-taking aimed at progress towards sustainability.

Journal ArticleDOI
TL;DR: In this article, the authors proposed a new integrated model for solving the distribution system planning (DSP) problem by implementing distributed generation (DG) as an attractive option in distribution utilities territories.
Abstract: This paper proposes a new integrated model for solving the distribution system planning (DSP) problem by implementing distributed generation (DG) as an attractive option in distribution utilities territories. The proposed model integrates a comprehensive optimization model and planner's experience to achieve optimal sizing and siting of distributed generation. This model aims to minimize DG's investment and operating costs, total payments toward compensating for system losses along the planning period, as well as different costs according to the available alternative scenarios. These scenarios vary from expanding of an existing substation and adding new feeders to purchasing power from an existing intertie to meet the load demand growth. Binary decision variables are employed in the proposed optimization model to provide accurate planning decisions. The present worth analysis of different scenarios is carried out to estimate the feasibility of introducing DG as a key element in solving the DSP problem.

Journal ArticleDOI
TL;DR: Baseline and recent bone marker levels were predictive of negative clinical outcomes in patients with bone metastases secondary to prostate cancer and to NSCLC and other solid tumors, reflecting the key role of osteolysis in the development of skeletal complications.
Abstract: Background: Whether bone markers have prognostic value in patients with bone metastases is unknown. We investigated this question in patients with bone metastases secondary to prostate cancer and to non‐small-cell lung cancer (NSCLC) and other solid tumors assigned to the placebo arms of two phase III trials of zoledronic acid. Methods: Levels of the urinary bone resorption marker N-telopeptide and the serum bone formation marker bone-specific alkaline phosphatase were assessed every 3 months for patients with prostate cancer (n 203) or NSCLC or other solid tumors (n 238) and were categorized as low or high. Patients were monitored for skeletal-related events, bone disease progression, and death. The relative risks (RRs) and 95% confidence intervals (CIs) for these outcomes were estimated for patients with high versus low levels of each marker using intensity-based multiple event and Cox regression models. All statistical tests were two-sided. Results: In each disease group and overall, high levels of each marker at the beginning of the study were statistically significantly associated with an increased risk of negative outcomes. Use of recent marker assessments as time-dependent covariates gave even greater prognostic significance. High N-telopeptide levels were a stronger prognostic indicator of negative outcomes than bone-specific alkaline phosphatase levels. In recent assessments, patients with high N-telopeptide levels had an increased relative risk of skeletal-related events (prostate cancer, RR 3.25, 95% CI 2.26 to 4.68, P<.001; NSCLC and other solid tumors, RR 1.79, 95% CI 1.15 to 2.79, P .010), disease progression (prostate cancer, RR 2.02, 95% CI 1.48 to 2.74, P<.001; NSCLC and other solid tumors, RR 1.91, 95% CI 1.16 to 3.15, P .011), and death (prostate cancer, RR 4.59, 95% CI 2.82 to 7.46, P<.001; NSCLC and other solid tumors, RR 2.67, 95% CI 1.85 to 3.85, P<.001) compared with patients with low N-telopeptide levels. Conclusions: Baseline and recent bone marker levels were predictive of negative clinical outcomes in patients with bone metastases secondary to prostate cancer and to NSCLC and other solid tumors. N-telopeptide levels were more consistent prognostic indicators than bonespecific alkaline phosphatase for all tumor types, reflecting the key role of osteolysis in the development of skeletal complications. [J Natl Cancer Inst 2005;97:59‐69]

Journal ArticleDOI
TL;DR: The model predicts that ONH biomechanics are strongly dependent on sCleral biomechanical properties, and suggests that interindividual variations in scleral properties could be a risk factor for the development of glaucoma.
Abstract: measures. RESULTS. The five input factors that had the largest influence across all outcome measures were, in ranked order: stiffness of the sclera, radius of the eye, stiffness of the lamina cribrosa, IOP, and thickness of the scleral shell. The five least influential factors were, in reverse ranked order: retinal thickness, peripapillary rim height, cup depth, cup-to-disc ratio, and pial thickness. Factor ranks were similar for various outcome measure groups and factor ranges. CONCLUSIONS. The model predicts that ONH biomechanics are strongly dependent on scleral biomechanical properties. Acute deformations of ONH tissues, and the consequent high levels of neural tissue strain, were less strongly dependent on the action of IOP directly on the internal surface of the ONH than on the indirect effects of IOP on the sclera. This suggests that interindividual variations in scleral properties could be a risk factor for the development of glaucoma. Eye size and lamina cribrosa biomechanical properties also have a strong influence on ONH biomechanics. (Invest Ophthalmol Vis Sci. 2005;46: 4189‐4199) DOI:10.1167/iovs.05-0541

Journal ArticleDOI
TL;DR: This article proposes a cardinality-based notation for feature modeling, which integrates a number of existing extensions of previous approaches, and introduces and motivate the novel concept of staged configuration.
Abstract: Feature modeling is a key technique for capturing commonalities and variabilities in system families and product lines. In this article, we propose a cardinality-based notation for feature modeling, which integrates a number of existing extensions of previous approaches. We then introduce and motivate the novel concept of staged configuration. Staged configuration can be achieved by the stepwise specialization of feature models or by multilevel configuration, where the configuration choices available in each stage are defined by separate feature models. Staged configuration is important because, in a realistic development process, different groups and different people make product configuration choices in different stages. Finally, we also discuss how multilevel configuration avoids a breakdown between the different abstraction levels of individual features. This problem, sometimes referred to as 'analysis paralysis', easily occurs in feature modeling because features can denote entities at arbitrary levels of abstraction within a system family. Copyright © 2005 John Wiley & Sons, Ltd.

Journal ArticleDOI
TL;DR: It is shown that a state which is maximally entangled in an inertial frame becomes less entangled if the observers are relatively accelerated, which shows that entanglement is an observer-dependent quantity in noninertial frames.
Abstract: Two observers determine the entanglement between two free bosonic modes by each detecting one of the modes and observing the correlations between their measurements. We show that a state which is maximally entangled in an inertial frame becomes less entangled if the observers are relatively accelerated. This phenomenon, which is a consequence of the Unruh effect, shows that entanglement is an observer-dependent quantity in noninertial frames. In the high acceleration limit, our results can be applied to a nonaccelerated observer falling into a black hole while the accelerated one barely escapes. If the observer escapes with infinite acceleration, the state's distillable entanglement vanishes.

Proceedings ArticleDOI
07 Aug 2005
TL;DR: A general framework for learning from labeled and unlabeled data on a directed graph in which the structure of the graph including the directionality of the edges is considered, which generalizes the spectral clustering approach for undirected graphs.
Abstract: We propose a general framework for learning from labeled and unlabeled data on a directed graph in which the structure of the graph including the directionality of the edges is considered. The time complexity of the algorithm derived from this framework is nearly linear due to recently developed numerical techniques. In the absence of labeled instances, this framework can be utilized as a spectral clustering method for directed graphs, which generalizes the spectral clustering approach for undirected graphs. We have applied our framework to real-world web classification problems and obtained encouraging results.

Book
22 Dec 2005
TL;DR: This chapter discusses the design and manufacture of fuel cells, as well as some of the technologies used in the manufacture of these cells, and their applications.
Abstract: Chapter 1. Introduction Chapter 2. Thermodynamics of Fuel Cells Chapter 3. Electrochemistry of Fuel Cells Chapter 4.Transport Phenomena in Fuel Cells Chapter 5. Alkaline Fuel Cells (AFCs) Chapter 6. Phosphoric Acid Fuel Cells (PAFCs) Chapter 7. Proton Exchange Membrane Fuel Cells (PEMFCs) Chapter 8. Molten Carbonates Fuel Cells (MCFCs) Chapter 9. Solid Oxide Fuel Cells (SOFCs) Chapter 10. Direct Methanol Fuel Cells (DMFCs) Appendix A Appendix B

Journal ArticleDOI
TL;DR: The results have implications for clinical assessment and management, genetic counseling and research into pathophysiological mechanisms, including several of later onset in 22q11DS.
Abstract: 22q11 Deletion Syndrome (22q11DS) is a common microdeletion syndrome with multisystem expression. Phenotypic features vary with age, ascertainment, and assessment. We systematically assessed 78 adults (36 M, 42 F; mean age 31.5, SD 10.5 years) with a 22q11.2 deletion ascertained through an adult congenital cardiac clinic (n = 35), psychiatric-related sources (n = 39), or as affected parents of subjects (n = 4). We recorded the lifetime prevalence of features requiring attention, with 95% confidence intervals (CI) not overlapping zero. Subtle learning difficulties, hypernasality and facial gestalt were not included. We investigated ascertainment effects using non-overlapping subgroups ascertained with tetralogy of Fallot (n = 31) or schizophrenia (n = 31). Forty-three features met inclusion criteria and were present in 5% or more patients, including several of later onset (e.g., hypothyroidism, cholelithiasis). Number of features per patient (median 9, range 3-22) correlated with hospitalizations (P = 0.0002) and, when congenital features were excluded, with age (P = 0.02). Adjusting for ascertainment, 25.8% (95% CI, 9.5-42.1%) of patients had cardiac anomalies and 22.6% (95% CI, 7.0-38.2%) had schizophrenia. Ascertainment subgroups were otherwise similar in median number and prevalence of features. Non-characteristic features are common in 22q11DS. Adjusting for ascertainment effects is important. Many treatable conditions may be anticipated and features may accumulate over time. The results have implications for clinical assessment and management, genetic counseling and research into pathophysiological mechanisms.

Journal ArticleDOI
TL;DR: In this article, the distribution of female hormones, 17β-estradiol and estrone, was determined in effluents of 18 selected municipal treatment plants across Canada, and the removal efficiency compared to the operational characteristics of the plants.

Journal ArticleDOI
TL;DR: Using switched Lyapunov functions, some new general criteria for exponential stability and asymptotic stability with arbitrary and conditioned impulsive switching are established and a new hybrid impulsive and switching control strategy for nonlinear systems is developed.
Abstract: In this note, a new class of hybrid impulsive and switching models is introduced and their asymptotic stability properties are investigated. Using switched Lyapunov functions, some new general criteria for exponential stability and asymptotic stability with arbitrary and conditioned impulsive switching are established. In addition, a new hybrid impulsive and switching control strategy for nonlinear systems is developed. A typical example, the unified chaotic system, is given to illustrate the theoretical results.

Journal ArticleDOI
TL;DR: The distinct physical, electronic, and mechanical properties of nanotubes are described and the challenges associated with CNTs, which remain to be fully addressed for their maximum utilization for biomedical applications are discussed.
Abstract: Carbon nanotubes (CNTs) have many unique physical, mechanical, and electronic properties. These distinct properties may be exploited such that they can be used for numerous applications ranging from sensors and actuators to composites. As a result, in a very short duration, CNTs appear to have drawn the attention of both the industry and the academia. However, there are certain challenges that need proper attention before the CNT-based devices can be realized on a large scale in the commercial market. In this paper, we report the use of CNTs for biomedical applications. The paper describes the distinct physical, electronic, and mechanical properties of nanotubes. The basics of synthesis and purification of CNTs are also reviewed. The challenges associated with CNTs, which remain to be fully addressed for their maximum utilization for biomedical applications, are discussed.

Journal ArticleDOI
TL;DR: In this article, the authors give a new heuristic for all of the main terms in the integral moments of various families of primitive $L$-functions and show that these moments can be modelled using Random Matrix Theory.
Abstract: We give a new heuristic for all of the main terms in the integral moments of various families of primitive $L$-functions. The results agree with previous conjectures for the leading order terms. Our conjectures also have an almost identical form to exact expressions for the corresponding moments of the characteristic polynomials of either unitary, orthogonal, or symplectic matrices, where the moments are defined by the appropriate group averages. This lends support to the idea that arithmetical $L$-functions have a spectral interpretation, and that their value distributions can be modelled using Random Matrix Theory. Numerical examples show good agreement with our conjectures.

Journal ArticleDOI
TL;DR: The present study has demonstrated for the first time a functional IFN-γ homologue in a fish species, strongly suggesting a conserved Th1 immune response is most likely present in lower vertebrates.
Abstract: IFN-gamma is one of the key cytokines in defining Th1 immune responses. In this study, an IFN-gamma homologue has been identified in rainbow trout Oncorhynchus mykiss, and its biological activities have been characterized. The trout IFN-gamma cDNA is 1034 bp in length and translates into a 180-aa protein. The first intron of the trout IFN-gamma gene contains highly polymorphic GACA minisatellites and 44-bp DNA repeats, giving rise to at least six alleles. IFN-gamma is structurally conserved among vertebrates, and a signature motif has been identified. A nuclear localization sequence known to be crucial for IFN-gamma biological activities is also present in the C-terminal region of the trout IFN-gamma. The IFN-gamma expression was induced in head kidney leukocytes by stimulation with PHA or poly(I:C) and in kidney and spleen of fish injected with poly(I:C). rIFN-gamma produced in Escherichia coli significantly stimulated gene expression of IFN-gamma-inducible protein 10 (gammaIP-10), MHC class II beta-chain, and STAT1, and enhanced respiratory burst activity in macrophages. Deletion of 29-aa residues from the C terminus containing the nuclear localization sequence motif resulted in loss of activity with respect to induction of gammaIP-10 in RTS-11 cells. Moreover, IFN-gamma-induced gammaIP-10 expression was completely abolished by the protein kinase C inhibitor staurosporine, and partially reduced by U0126, a specific inhibitor for ERKs. Taken together, the present study has demonstrated for the first time a functional IFN-gamma homologue in a fish species, strongly suggesting a conserved Th1 immune response is most likely present in lower vertebrates.