Ranaviruses : Detection, differentiation and host immune response

Ranaviruses cause systemic infection in fish, amphibians and reptiles. Disease outbreaks associated with ranaviruses have been reported worldwide, and their harmful impact on aquaculture and natural populations of host animals has drawn attention to this group of viruses. In this research, genetic relationships among members of genus Ranavirus, including several known and less studied isolates, were investigated. Sequences of several viral genes were obtained and the phylogenetic analyses based on the sequence data were performed. The results confirm that the genus Ranavirus encompasses genetically divergent isolates. Most of the ranaviruses characterized to date are closely related to epizootic haematopoietic necrosis virus (EHNV) and frog virus 3 (FV3). Santee-Cooper ranaviruses and grouper iridoviruses cluster separately from the main group of ranaviruses. Methods based on polymerase chain reaction (PCR) and subsequent restriction enzyme analysis (REA) were developed for the detection and differentiation of ranaviruses. PCR based on viral DNA polymerase (DNApol) gene was able to detect 13 different ranavirus isolates. The differentiation of isolates was accomplished with REA of the viral DNApol and neurofilament-triplet H1-like protein genes. Quantitative PCR based on the viral DNApol gene was developed in order to detect a wide range of ranaviruses and to estimate the number of virions in a sample. Pathogenicity of nine different ranavirus isolates to rainbow trout (Oncorhynchus mykiss) was studied. None of the isolates caused signs of disease, but virus was isolated from few of the fish collected during the challenge trial. The results indicate that persistent ranavirus infections may occur in certain conditions and that rainbow trout could act as a vector species for ranaviruses. Fish epithelial cells were infected with four different ranaviruses in order to study the host immune response to ranavirus infection. All ranavirus isolates elicited apoptosis in the fish epithelial cells, but the immune response elicited varied between different ranaviruses. A strong pro-inflammatory response was induced by FV3 and EHNV, whereas European catfish virus and doctor fish virus elicited a mild increase in the expression of regulatory cytokine TGF-β. Gene expression of beta-2 microglobulin was enhanced by all viral isolates, indicating that a pathogen presentation pathway based on MHC class I molecules was activated due to ranavirus infection.Ranavirukset aiheuttavat systeemisen infektion kaloissa, sammakkoeläimissä ja matelijoissa. Ranavirusten aiheuttamia taudinpurkauksia on raportoitu ympäri maailmaa niin kasvatetuissa kuin luonnonvaraisissa isäntäeläimissäkin. Tässä tutkimuksessa selvitettiin useiden aikaisemmin tunnettujen ja ennestään tuntemattomien ranavirusten geneettisiä sukulaisuussuhteita. Useita ranavirusten perimään kuuluvia geenejä sekvensoitiin ja niiden perusteella tehtiin fylogeneettisiä analyysejä. Tulokset vahvistavat, että Ranavirus-sukuun kuuluu geneettisesti toisistaan poikkeavia viruksia. Useimmat ranaviruksista ovat läheistä sukua epizootic haematopoietic necrosis (EHN)- ja frog virus 3 (FV3)-viruksille, kun taas Santee-Cooper ranavirukset ja grouper iridovirukset eroavat selvästi muista ranaviruksista. Tutkimuksessa kehitettiin polymeraasiketjureaktioon (PCR) ja restriktioentsyymianalyysiin (REA) perustuvia tunnistus- ja erottelumenetelmiä ranaviruksille. Ranavirusten DNA polymeraasi (DNApol)-geeniin perustuvan PCR:n avulla tunnistettiin 13 eri ranaviruskantaa. Virukset eroteltiin toisistaan ranavirusten DNApol- ja NF-H1-geeneihin perustuvalla REA-menetelmällä. DNApol-geeniin perustuvalla kvantitatiivisella PCR-menetelmällä pystyttiin ranavirusten tunnistamisen lisäksi selvittämään viruspartikkeleiden määrä näytteessä. Yhdeksän eri ranaviruskannan taudinaiheuttamiskykyä tutkittiin kirjolohella (Oncorhynchus mykiss). Mitkään tutkituista viruksista eivät aiheuttaneet taudin oireita, mutta osasta kirjolohia pystyttiin eristämään ranavirus kokeen aikana. Tulosten mukaan ranavirukset voivat tietyissä olosuhteissa säilyä isäntäeläimessä ja kirjolohi voi näin ollen toimia ranavirusinfektion välittäjänä. Ranavirusten aiheuttamaa immuunivastetta tutkittiin infektoimalla kalojen epiteelisoluja neljällä eri ranaviruskannalla. Kaikki neljä viruskantaa aiheuttivat ohjelmoitua solukuolemaa eli apoptoosia, mutta eri virukset saivat aikaan toisistaan poikkeavan immuunigeenien ilmentymisen kalojen epiteelisoluissa. EHNV ja FV3 aiheuttivat voimakkaan pro-inflammatorisen vasteen, kun taas European catfish virus ja doctor fish virus lievästi lisäsivät regulatorisen sytokiinin TGF-betan ilmentymistä. Kaikki ranavirukset lisäsivät beta-2 mikroglobuliini-geenin ilmentymistä, mikä osoittaa, että luokan I MHC -molekyyleihin perustuva antigeenien esittely aktivoitui ranavirusinfektion seurauksena

Comparative study of ranavirus isolates from cod (Gadus morhua) and turbot (Psetta maxima) with reference to other ranaviruses

Two iridovirus isolates recovered from cod (Gadus morhua) and turbot (Psetta maxima) in Denmark were examined in parallel with a panel of other ranaviruses including frog virus 3 (FV3), the reference strain for the genus Ranavirus. The isolates were assessed according to their reactivity in immunofluoresent antibody tests (IFAT) using both homologous and heterologous antisera and their amplification in PCR using primers targeting five genomic regions. The corresponding PCR fragments were sequenced, and the sequences obtained were used in phylogenetic analysis. In addition, the pathogenicity to rainbow trout under experimental challenge conditions was investigated. The viruses were serologically and genetically closely related to highly pathogenic ranaviruses such as European catfish iridovirus (ECV), European sheatfish iridovirus (ESV) and epizootic haematopoietic necrosis virus (EHNV). The challenge trials indicate that rainbow trout fry cultured at 15 C are not target species for the virus isolates in the present panel. We suggest that the two isolates belong in the genus Ranavirus and propose the name Ranavirus maxima (Rmax) for the turbot isolate

Los diálogos entre el contenido y la lengua: cautelas y retos en la emergencia de un programa de educación bilingüe

This paper presents a set of ideas about the basics for developing interdisciplinary dialogues between content (science) and language (English) in bilingual educational processes, under the premise that a satisfactory relationship between those elements help guarantee successful content-based instruction (CBI) in its form known as sheltered instruction. Additionally, a practical example (based on a science curriculum) is presented to demonstrate some principles that inform approaches to teaching such content. Finally, based on the authors’ interdisciplinary work and pedagogical experiences, some recommendations on teaching content and language in bilingual settings are presented in the form of cautions (a balance of actions) and challenges (prospects).Este artículo presenta un conjunto de ideas fundamentales para llevar a cabo diálogos interdisciplinarios entre contenido (ciencias naturales) y lengua (inglés) en procesos de educación bilingüe, bajo premisa de que un vínculo satisfactorio entre ambos elementos ayuda a garantizar una instrucción basada en contenidos (CBI) exitosa, particularmente, en su forma de instrucción amparada. En adición, un ejemplo práctico (basado en un currículo de ciencias naturales) se presenta para demostrar algunos principios que dan cuenta de algunos enfoques para enseñar dicho contenido. Finalmente, con base en el trabajo interdisciplinario y la experiencia pedagógica de sus autores, se presentan algunas recomendaciones sobre la enseñanza de contenido y lengua en ambientes bilingües, a manera de cautelas (balance de acciones) y retos (prospectivas)

SIGNIFICANCE OF BOTH INTERNAL AND EXTERNAL BOUNDARY CONDITIONS ON HUMAN THERMAL SENSATION

ABSTRACT This paper describes the basic features of a new advanced human thermal model (HTM), which is integrated with a building simulation tool. The thermal sensation calculation of the model has been validated using dynamical temperature step change test results. This new methodology seems promising, and significance of both internal (metabolic rate and clothing) and external (air and surface temperature levels, air velocity, and humidity) boundary conditions can be estimated. This is beneficial, for example, when evaluating new technical concepts for future energy-efficient buildings