bluuebunny/crossref_metadata_2025_split huggingface dataset:
Physical and Functional Interactions between Pathogen-Induced Arabidopsis WRKY18, WRKY40, and WRKY60 Transcription Factors
Authors: Xu Xinping , Chen Chunhong , Fan Baofang , Chen Zhixiang 
Published: April 2006

Abstract
Limited information is available about the roles of specific WRKY transcription factors in plant defense. We report physical and functional interactions between structurally related and pathogen-induced WRKY18, WRKY40, and WRKY60 transcription factors in Arabidopsis thaliana. The three WRKY proteins formed both homocomplexes and heterocomplexes and DNA binding activities were significantly shifted depending on which WRKY proteins were present in these complexes. Single WRKY mutants exhibited no or small alterations in response to the hemibiotrophic bacterial pathogen Pseudomonas syringae and the necrotrophic fungal pathogen Botrytis cinerea. However, wrky18 wrky40 and wrky18 wrky60 double mutants and the wrky18 wrky40 wrky60 triple mutant were substantially more resistant to P. syringae but more susceptible to B. cinerea than wild-type plants. Thus, the three WRKY proteins have partially redundant roles in plant responses to the two distinct types of pathogens, with WRKY18 playing a more important role than the other two. The contrasting responses of these WRKY mutants to the two pathogens correlated with opposite effects on pathogen-induced expression of salicylic acid–regulated PATHOGENESIS-RELATED1 and jasmonic acid–regulated PDF1.2. While constitutive expression of WRKY18 enhanced resistance to P. syringae, its coexpression with WRKY40 or WRKY60 made plants more susceptible to both P. syringae and B. cinerea. These results indicate that the three WRKY proteins interact both physically and functionally in a complex pattern of overlapping, antagonistic, and distinct roles in plant responses to different types of microbial pathogens.
γ-Tubulin Is Essential for Acentrosomal Microtubule Nucleation and Coordination of Late Mitotic Events inArabidopsis
Authors: Binarová Pavla , Cenklová Věra , Procházková Jiřina , Doskočilová Anna , Volc Jindřich , Vrlík Martin , Bögre László 
Published: April 2006

Abstractγ-Tubulin is required for microtubule (MT) nucleation at MT organizing centers such as centrosomes or spindle pole bodies, but little is known about its noncentrosomal functions. We conditionally downregulated γ-tubulin by inducible expression of RNA interference (RNAi) constructs in Arabidopsis thaliana. Almost complete RNAi depletion of γ-tubulin led to the absence of MTs and was lethal at the cotyledon stage. After induction of RNAi expression, γ-tubulin was gradually depleted from both cytoplasmic and microsomal fractions. In RNAi plants with partial loss of γ-tubulin, MT recovery after drug-induced depolymerization was impaired. Similarly, immunodepletion of γ-tubulin from Arabidopsis extracts severely compromised in vitro polymerization of MTs. Reduction of γ-tubulin protein levels led to randomization and bundling of cortical MTs. This finding indicates that MT-bound γ-tubulin is part of a cortical template guiding the microtubular network and is essential for MT nucleation. Furthermore, we found that cells with decreased levels of γ-tubulin could progress through mitosis, but cytokinesis was strongly affected. Stepwise diminution of γ-tubulin allowed us to reveal roles for MT nucleation in plant development, such as organization of cell files, anisotropic and polar tip growth, and stomatal patterning. Some of these functions of γ-tubulin might be independent of MT nucleation.
Dynamic and Compensatory Responses ofArabidopsisShoot and Floral Meristems toCLV3Signaling
Authors: Müller Ralf , Borghi Lorenzo , Kwiatkowska Dorota , Laufs Patrick , Simon Rüdiger 
Published: April 2006

AbstractIn Arabidopsis thaliana, the stem cell population of the shoot system is controlled by regulatory circuitry involving the WUSCHEL (WUS) and CLAVATA (CLV1-3) genes. WUS signals from the organizing center (OC) to promote stem cell fate at the meristem apex. Stem cells express the secreted peptide CLV3 that activates a signal transduction cascade to restrict WUS expression, thus providing a feedback mechanism. Stem cell homeostasis is proposed to be achieved by balancing these signals. We tested the dynamics of CLV3 signaling using an inducible gene expression system. We show here that increasing the CLV3 signal can very rapidly repress WUS expression during development, which in turn causes a fast reduction of CLV3 expression. We demonstrate that increased CLV3 signaling restricts meristem growth and promotes allocation of peripheral meristem cells into organ primordia. In addition, we extend the current model for stem cell control by showing that meristem homeostasis tolerates variation in CLV3 levels over a 10-fold range and that high-level CLV3 signaling can be partially compensated with time, indicating that the level of CLV3 expression communicates only limited information on stem cell number to the underlying OC cells.
Endogenous and Synthetic MicroRNAs Stimulate Simultaneous, Efficient, and Localized Regulation of Multiple Targets in Diverse Species
Authors: Alvarez John Paul , Pekker Irena , Goldshmidt Alexander , Blum Eyal , Amsellem Ziva , Eshed Yuval 
Published: April 2006

AbstractRecent studies demonstrated that pattern formation in plants involves regulation of transcription factor families by microRNAs (miRNAs). To explore the potency, autonomy, target range, and functional conservation of miRNA genes, a systematic comparison between plants ectopically expressing pre-miRNAs and plants with corresponding multiple mutant combinations of target genes was performed. We show that regulated expression of several Arabidopsis thaliana pre-miRNA genes induced a range of phenotypic alterations, the most extreme ones being a phenocopy of combined loss of their predicted target genes. This result indicates quantitative regulation by miRNA as a potential source for diversity in developmental outcomes. Remarkably, custom-made, synthetic miRNAs vectored by endogenous pre-miRNA backbones also produced phenocopies of multiple mutant combinations of genes that are not naturally regulated by miRNA. Arabidopsis-based endogenous and synthetic pre-miRNAs were also processed effectively in tomato (Solanum lycopersicum) and tobacco (Nicotiana tabacum). Synthetic miR-ARF targeting Auxin Response Factors 2, 3, and 4 induced dramatic transformations of abaxial tissues into adaxial ones in all three species, which could not cross graft joints. Likewise, organ-specific expression of miR165b that coregulates the PHABULOSA-like adaxial identity genes induced localized abaxial transformations. Thus, miRNAs provide a flexible, quantitative, and autonomous platform that can be employed for regulated expression of multiple related genes in diverse species.
Effect of environmental conditions on the infectivity of Flexibacter columnaris to fish
Authors: WAKABAYASHI H. 
Published: April 2006

Abstract. Columnaris disease, Flexibacter columnaris infection, was first described in North America. Recent publications indicate that its distribution is worldwide. Both warmwater and coldwater fish are infected with F. columnaris. All freshwater fish are probably susceptible to the disease under environmental conditions favourable to the bacterium and stressful to the fish. Flexibacter columnaris cannot tolerate sea water. Generally, outbreaks occur when the average water temperatures reach 15°C. The bacterium apparently enters the fish through the skin and gills. The swarms of bacteria involved give the lesions a characteristic yellow pigmentation. The external lesions destroy the skin, muscle and gill tissues. It is relatively easy to isolate the bacteria from the internal organs of the diseased fish, but there is no evidence of internal tissue damage. In this short review, emphasis is placed on several factors relative to water environment which play a role in the development of outbreaks of columnaris disease:

The optimum temperature for an outbreak of F. columnaris infection is thought to be between 20 and 30°C. Mortalities seldom occur at temperatures below 15°C, although highly virulent strains can kill fish at lower temperatures.
Flexibacter columnaris can survive longer in water of normal to high hardness, as well as in water containing small amounts of sodium, potassium, calcium or magnesium salts, but it cannot live in sea water.
Flexibacter columnaris grows well on paniculate fish feeds so that such deposits in the water may act as reservoirs of infection.
An important source of infection is feral fish. In the Columbia River or the Fraser River, resident coarse fish such as suckers, Catostomus spp., are thought to transmit the infection to returning adult salmon.
Flexibacter columnaris fails to invade fish in the presence of competitive bacteria like Citrobacter freundii when its initial numbers are approximately one in a 100 less than those of the competitors.
Crowding seems to be not only a stressor for fish, but also a factor that increases the chance of adhesion of F. columnaris to the external tissues of fish.
Cell‐mediated immune response of goldfish, Carassiusaurafus (L.), to Ichthyophthirius multifiliis
Authors: Sin Y M , Ling K H , Lam T J 
Published: April 2006

AbstractGoldfish, Carassius auratus (L.), were intraperitoneally injected with two doses of Ichthyophthirius multifiliis (each containing 2.3 × 106 live tomites) in saline, 30 days apart. The control fish were injected with saline only. Two weeks after the last vaccination, fish of both groups were intradermally injected with 2.5 × 105 live tomites for skin tests. The skin at the antigen‐injected site of the vaccinated fish increased in thickness from 8 h onwards and reached a peak at 24 h. Histological study showed a heavy infiltration of mononuclear leucocytes at the antigen‐injected site. In contrast, no such changes were encountered in control fish. The migration area of pronephros cells from the vaccinated fish was significantly inhibited, in vitro, compared to controls with the presence of antigens. These findings suggest that the tomite‐vaccinated fish produced a cell‐mediated immune response. However, vaccinated fish also exhibited significantly higher titres of immobilizing antibodies in their sera and mucus than the controls. Therefore, it is likely that both humoral and cell‐mediated immune responses have to work closely together to eliminate the infectious tomites of I. multifiliis which succeed in penetrating the fish epithelial tissues.
Development of a nitrocellulose‐enzyme immunoassay for the detection of yellow‐head virus from penaeid shrimp
Authors: Lu Y. , Tapay L. M. , Loh P. C. 
Published: April 2006

AbstractA nitrocellulose‐enzyme immunoassay (NC‐EIA) employing horseradish peroxidase (HRP) was developed for the detection of yellow‐head virus in the tissues of infected penaeid shrimp. Two substrates, DAB (3,3¢‐diaminobenzidine retrahydrochloride) and TMB (3,3¢5,5¢‐tetramethylbenzidine) for HRP were evaluated. The TMB was found to produce a more distinct and easily recognizable colour product and provided enhanced sensitivity (0.4 ng for TMB versus 0.8 ng viral protein for DAB). Under the present format, the NC‐EIA was capable of detecting as little as 100 TCID50 of virus in infected tissues. Uninfected tissue homogenates yielded no significant background colouration.
Streptococcosis in cultured turbot, Scopthalmus maximus (L.), associated with Streptococcus parauberis
Authors: Domeénech A , Derenaáandez‐Garayzábal J F , Pascual C , Garcia J A , Cutuli M T , Moreno M A , Collins M D , Dominguez L 
Published: April 2006

AbstractSeveral strains of Garm‐positive short rod (coccibacilli)‐shaped bacteria were isolated from diseased cultured turbot, Scophthalmus maximus (L.), in the North of Spain with lesions and signs of Spain with lesions and signs of streptocecosis. The α‐haemolytic streptoceoccus‐like organisms from diseased turbot were identified by physiological, biochemical and 16S rRNA gene sequence analysis as Streptococcus parauberis. This is the first report of S. parauberis associated with fish disease.
Comparative studies of PKX and Sphaerospora spp. from salmonids using lectin and monoclonal antibody staining techniques
Authors: de Mateo M Marin , McGeorge J , Morris D , Kent M L 
Published: April 2006

AbstractThe results of comparative immunohisto‐chemical staining studies with two lectin probes, GS‐I and SBA, and five monoclonal antibodies raised against the PKX myxosporean are presented. In order to investigate the postulated link between PKX and Sphaerospora spp., the lectins and monoclonal antibodies were tested against PKX, Sphaerospora renicola, Sphaerospora oncorhynchi, Sphaerospora elegam, Sphaerospora truttae and Sphaero‐spora sp. from Atlantic salmon, Salmo salar L., and Ceratomyxa shasta. SBA appears a useful tool for tbe diagnosis of all Sphaerospora spp. infections and was also positive for C. shasta. GS‐I and monoclonal antibodies (12, C5, D4 and A3) appear to be specific for both the extrasporogonic and sporogonic stages of PKX. Although MabB4 was raised to PKX, it appears to stain some of the sporogonic stages of Sphaerospora spp. but not C. shasta. The results of the lectin and monoclonal staining of PKX and Sphaerospora oncorhynchi indicated that further work was required to prove or disprove the hypothesis that PKX and S, oncorhynchi are the same organism.
The postponement of non‐culturability in Aeromonas salmonicida
Authors: Pickup R W , Rhodes G , Cobban R J , Clarke K J 
Published: April 2006

Abstract Aeromonas salmonicida, the causative agent of furunculosis in fish, has been shown to become non‐culturable but viable after inoculation in fresh water. The onset of non‐culturability is entirely predictable, but can be delayed by inoculation at high concentration or amendment with nutrients. This paper reports that non‐culturability can be postponed by the addition of both the amino acids methionine and arginine to microcosms inoculated with A. salmonicida. During these experiments, A. salmonicida decreased in cell size and became rounded. This was regardless of whether it received an amino acid supplement or not. We observed that cells receiving both amino acids remained culturable despite their reduction in cell size to less than 1 μm. Therefore, it would appear that the reduction in size and associated morphological change cannot be taken as an indicator of non‐culturability, although it may be a significant step in that direction in some cases.
Humoral immune response of Japanese eel, Anguilla japonica Temminck & Schlegel, to Pleistophora anguillarum Hoshina, 1951 (Microspora)
Authors: Hung H‐W , Lo C‐F , Tseng C‐C , Kou G‐H 
Published: April 2006

AbstractA humoral response of Japanese eel, Anguilla japonica Temminck & Schlegel, to the microsporean Pleistophora anguillarum Hoshina was demonstrated using immunoblotting and an enzyme‐linked immunosorbent assay (ELISA). Japanese eel immunoglobulin was purified by affinity chromatography. The immunoglobulin was composed of 25‐kDa light chains and 72‐kDa heavy chains. The ELISA values of P. anguillarum antibodies in naturally infected fish sera were significantly higher than those of clinically healthy fish. Spore proteins from the microsporean were separated by electrophoresis and subjected to analysis by Western blot. Sera from naturally infected fish showed different reaction patterns to the spore proteins. While the sera randomly selected from naturally infected eels all showed a significant positive reaction to P. anguillarum antigens, the mucus from only three out of the nine infected eels reacted positively in the ELISA test. Subsequent analyses indicated that there was no significant difference in the amount of mucus immunoglobulin among the tested eels. Therefore, the generally lower ELISA values of mucosal anti‐P. anguillarum antibodies from the infected eels tested were evidently not caused by a lack of immunoglobulin per se, but seem to be the result of a lack of anti‐P. anguillarum antibodies in the mucus and/or a lower affinity in the anti‐P. anguillarum antibodies that were present.
Digenean (Bucephalidae) infections in commercial scallops, Pecten fumatus Reeve, and doughboy scallops, Chlamys (Mimachlamys) asperrima (Lamarck), in Jervis Bay, New South Wales
Authors: Heasman M P , O'Connor W A , Frazer A W J 
Published: April 2006

AbstractSympatric populations of the hermaphroditic scallop, Pecten fumatus Reeve, and of the dioecious scallop, Chlamys (Mimachlamys) asperrima (Lamarck), from Jervis Bay, New South Wales, Australia, were sampled between October 1991 and December 1994. Over the first 2 years, 5.1% of adult P. fumatus and 4.5% of adult C. asperrima were infected with a trematode, Bucephalus sp., that causes parasitic castration. A significant increase in the numbers of infected scallops occurred in spring 1993, teaching 63% in P. fumatus and 24% in C asperrima in May and March 1994, respectively. The prevalence of infection increased with scallop size, reaching 66% in P. fumatus greater than 80 mm in shell height and 40% in C. asperrima greater than 75 mm in 1994. Seasonal and interannual variations in parasitism for the P. fumatus recorded over a continuous period of 5 years in Jervis Bay are discussed, as are interspecies differences and the potential impact of the parasitic castration on reproductive potential and marketability of P. fumatus and C. asperrima.
Experimental infection of Atlantic halibut, Hippoglossus hippoglossus L., yolk‐sac larvae with infectious pancreatic necrosis virus: detection of virus by immunohistochemistry and in situ hybridization*
Authors: Biering E , Bergh Ø 
Published: April 2006

AbstractThree different concentrations (107, 105 and 103 TCID50 ml−1) of infectious pancreatic necrosis virus (IPNV) serotype Sp isolated from Atlantic halibut, Hippoglossus hippoglossus L., were used to bath‐challenge Atlantic halibut yolk‐sac larvae. The larvae challenged with 107 TCID50 ml−1 suffered significantly higher cumulative mortality than the other challenged groups and the control group, and affected individuals displayed necrosis of the intestine, liver and kidney. In larvae from the groups challenged with 107 and 105 TCID50 ml−1, IPNV was detected by immunohistochemistry and in situ RNA/DNA hybridization in the intestine, liver and kidney. In addition, some individuals stained IPNV‐positive in the heart and eye/ brain region. Detection by in situ hybridization did not appear to be more sensitive than immunohistochemistry. However, background staining was virtually absent in comparison with immunohistochemistry, and the staining seemed to be more distinctly localized to the cytoplasm of infected cells. The results show that farmed halibut yolk‐sac larvae can be infected by IPNV immediately after hatching, with resulting high mortality. As the larvae are not immunologically mature at this stage of development, vaccination is not recommended.
Recombinant channel catfish virus (Ictalurid herpesvirus 1) can express foreign genes and induce antibody production against the gene product
Authors: Zhang H G , Hanson L A 
Published: April 2006

AbstractThe potential use of channel catfish virus (CCV) (Ictalurid herpesvirus 1) as a vaccine vector for the channel catfish industry was investigated by inserting the Escherichia coli lacZ gene into the CCV genome and evaluating the immune response to the foreign gene product in catfish exposed to the recombinant. The recombinant virus was produced by inserting the lacZ in reading frame with the ATG start codon of the CCV thymidine kinase (TK) gene in the recombinant transfer plasmid pBSCV457 described previously. The plasmid was then cotransfected with CCV DNA in a TK gene‐mediated selectable homologous recombination. The recombinant progeny were selected by resistance to 0.1 mM acycloguanosine (acyclovir) and the production of blue plaques in the presence of 5‐bromo‐4‐chloro‐3‐indolyl‐β‐D‐galactopyranoside (X‐gal). The resultant construct (CCVlacZ) was TK−, and contained the lacZ gene at both TK loci in the genome. β‐Galactosidase expression in infected CCO ceils reached 0.53 μg per 106 CCO cells at 12 h post‐infection. When channel catfish fingerlings were immersion exposed to CCVlacZ, these developed an antibody response to the inserted foreign gene product which peaked at approximately 15–20 days post‐infection. Additionally, the anti‐β‐galactosidase response was significantly enhanced when the fingerlings were re‐exposed to the virus 20 days after the initial exposure. These results demonstrate that foreign genes can be inserted into and expressed by CCV and that such constructs could be used as vaccine vectors.
Accumulation of immunomodulatory laminaran (β(1,3)‐D‐glucan) in the heart, spleen and kidney of Atlantic cod, Gadus morhua L.
Authors: Dalmo R A , Ingebrigtsen K , Sveinbjørnsson B , Seljelid R 
Published: April 2006

AbstractThe tissue distribution of 3H‐ and FITC‐lammaran in Atlantic cod, Gadus morhua L., was investigated after intravenous administration. Liquid scintillation counting and whole‐body autoradiography revealed a substantial accumulation of 3H‐labelled laminaran in the heart throughout the experimental period (1 h to 12 days). High amounts of the immunomodulator were also present in the spleen, anterior kidney and posterior kidney during the study. Renal excretion and intestinal exsorption were the main elimination pathways. Fluorescence microscopic examination revealed accumulation of FITC‐labelled laminaran in macrophages in the kidney and ellipsoid sheath cells (macrophages and reticular cells) in the spleen. Furthermore, endothelial entrapment in the heart was pronounced. Endothelial cells in the kidney also contained the FITC‐labelled immunomodulator. Immunohistochemical analysis, using anti‐β(l,3)‐D‐glucopyranose antibody, also showed endothelial uptake of laminaran in the heart. The present investigation shows that laminaran accumulates and is retained in immunologically relevant cells in the Atlantic cod.
Production of monoclonal antibodies against yellowtail ascites virus
Authors: Nakajima K , Sorimachi M 
Published: April 2006

AbstractA total of 31 antibody‐secreting hybridoma cells against the yellowtail ascites virus (YAV) were established. These monoclonal antibodies (MAbs) reacted with the cytoplasm of YAV‐infected CHSE‐214 cells, but not with uninfected CHSE‐214 cells in an immunofluorescence test. Using these MAbs, two classes of polypeptides (VP2 and VP3) were characterized by immunoprecipitation followed by SDS‐PAGE, although one MAb did not react with either polypeptide. Fifteen out of the 17 MAbs that were reactive with VP2 polypeptides neutralized virus infectivity, but all 13 MAbs that were reactive with VP3 did not neutralize infectivity. In the immunofluorescence test, 29 out of the 31 MAbs obtained showed the same reaction pattern to 12 YAV isolates from yellowtail, Seriola quinqueradiata, goldstriped amberjack, Seriola aureovittata, and threeline grunt, Parapristipoma trilineatum, from different geographical regions. The remaining two MAbs showed slightly different reaction patterns to the YAV isolates. The reaction patterns of the MAbs to the VR‐299, Sp and Ab strains of IPNV were also investigated. Fourteen MAbs reacted to all three IPNV strains. The other 17 MAbs showed a negative reaction with at least one strain.