bluuebunny/crossref_metadata_2025_split huggingface dataset:
Early signalling events in the Avr9/Cf‐9‐dependent plant defence response
Authors: Romeis Tina , Tang Saijun , Hammond‐Kosack Kim , Piedras Pedro , Blatt Mike , Jones Jonathan D. G. 
Published: March 2003

AbstractResistance of tomato to the leaf mould fungus Cladosporium fulvum is controlled by the interaction between a plant‐encoded resistance gene (Cf‐9) and pathogen‐encoded avirulence (Avr9) gene. Our objective is to understand the underlying molecular mechanisms that transmit the Cf‐9/Avr9‐dependent pathogen perception event and activate the plant defence response. Our approach toward the understanding of Cf‐function is based on the analysis of early Cf‐9/Avr9‐mediated responses and signalling events. Because Cf‐9 transgenically expressed in tobacco retains its specificity and activity to the Avr9 elicitor, signalling experiments were conducted in the heterologous system using these transgenic lines or derived Cf9 tobacco cell cultures.Among the earliest responses to the Avr9/Cf‐9 elicitation event were rapid changes in ion‐fluxes, the synthesis of active oxygen species (AOS), probably catalysed by a plant NADPH‐oxidase, and the transient activation of two MAP kinases. These kinases were identified as WIPK (wounding‐induced protein kinase) and SIPK (salicylic‐acid induced kinase) from tobacco. Studies with pharmacological inhibitors suggested that the MAP kinases are located in an independent signalling pathway from the Avr9/Cf‐9‐dependent synthesis of AOS. SIPK and WIPK were involved in pathogen‐related elicitation processes as well as in abiotic stress responses. This indicates that the plant defence is triggered via a signalling network that shares components with pathways originating from abiotic environmental stress stimuli.
Infection of Arabidopsis thaliana leaves with Albugo candida (white blister rust) causes a reprogramming of host metabolism
Authors: Chou Hsueh‐Mei , Bundock Nicholas , Rolfe Stephen A. , Scholes Julie D. 
Published: March 2003

Abstract Albugo candida (Pers.) (O.) Kunze is a biotrophic pathogen which infects the crucifer Arabidopsis thaliana (L.) Heynh forming discrete areas of infection. Eight days after inoculation of leaves, white blisters became visible on the under surface of the leaf although no symptoms were apparent on the upper surface. By day 14, the region of leaf invaded by fungal mycelium had become chlorotic. Recently it has been hypothesized that an accumulation of soluble carbohydrates, following an increase in invertase activity, may trigger sugar signal transduction pathways leading to the repression of photosynthetic gene expression and to the induction of defence proteins. This hypothesis was investigated by quantifying localized changes in carbohydrate and photosynthetic metabolism and the expression of genes encoding photosynthetic and defence proteins. Quantitative imaging of chlorophyll fluorescence revealed that the rate of photosynthesis declined progressively in the invaded regions of the leaf. However, in uninfected regions of the infected leaf the rate of photosynthesis was similar to that measured in the control leaf until late on during the infection cycle when it declined. Images of nonphotochemical fluorescence quenching (NPQ) suggested that the capacity of the Calvin cycle had been reduced in infected regions and that there was a complex metabolic heterogeneity within the infected leaf. A. candida also caused localized changes in the carbohydrate metabolism of the leaf; soluble carbohydrates accumulated in the infected region whereas the amount of starch declined. The reverse was seen in uninfected regions of the infected leaf; carbohydrates did not accumulate until late on during infection and the amount of starch increased as the infection progressed. There was an increase in the activity of invertases which was confined to regions of the leaf invaded by the fungal mycelium. The increase in apoplastic invertase activity was of host origin, as mRNA levels of the ATβFRUCT1 gene (measured by semiquantitative RT‐PCR) increased 40‐fold in the infected region. The increase in soluble invertase activity resulted from the appearance of a new isoform in the invaded region of the leaf. Current evidence suggests that this was of fungal origin. Northern blot analysis of cab and rbcS showed that photosynthetic gene expression was repressed in the infected leaf from 6 days after inoculation (DAI) when compared to control leaves. In contrast, there was no detectable induction of defence proteins in the infected leaf. These data are discussed in the context of the sugar‐sensing hypothesis presented above.
Differential expression of two Blumeria graminis chitin synthase genes
Authors: Zhang Ziguo , Hall Alison , Perfect Emma , Gurr Sarah J. 
Published: March 2003

AbstractTwo Blumeria graminis chitin synthase genes, designated BgChs1 and BgChs2 were cloned and characterized following the synthesis and use of degenerate PCR primers designed to the conserved regions of fungal chitin synthase (Chs) genes. Their sequences revealed high similarity with the Chs genes previously cloned from other fungi and placed BgChs1 and BgChs2 with the classes I and V, respectively. Each gene was present as a single copy within the barley powdery mildew genome. Semi‐quantitative RT‐PCR assays revealed BgChs1 to be up‐regulated at both the primary germ tube (PGT) and appressorial germ tube (AGT) stages of differentiation whilst the BgChs2 transcript was up‐regulated at the PGT stage. The B. graminisβ‐tubulin gene was used as a control for all RT‐PCR reactions. The BgChs1 transcript was some 30 fold less abundant than the β‐tubulin transcript and BgChs2 was some 30 fold rarer than the BgChs1 transcript. The effects of the chitin substrate analogues nikkomycin Z and polyoxin D on conidial morphogenesis were assessed. These nucleoside peptide inhibitors did not affect germination but both polyoxin D and nikkomycin Z treatment led to a large population of abnormally swollen ‘balloon‐shaped’ AGTs, whilst by 12 h after inoculation polyoxin treatment caused the swollen germ tubes to burst.
Cloning and characterization of a glutathione S‐transferase homologue from the plant pathogenic fungus Botrytis cinerea‡
Authors: Prins Theo W. , Wagemakers Lia , Schouten Alexander , Van Kan Jan A. L. 
Published: March 2003

AbstractA gene was cloned from Botrytis cinerea that encodes a protein homologous to glutathione S‐transferase (GST). The gene, denominated Bcgst1, is present in a single copy and represents the first example of such a gene from a filamentous fungus. The biochemical function of GSTs is to conjugate toxic compounds to glutathione, thereby detoxifying the compound. In many other organisms, GST plays a role in chemical stress tolerance. We anticipated that GST functions for B. cinerea as a potential virulence factor, enabling the fungus to tolerate fungitoxic plant defence compounds. The expression of Bcgst1 mRNA under various presumably stressful conditions was investigated. Bcgst1 mRNA is expressed at a basal level in liquid cultures and is induced upon addition of hydrogen peroxide to the medium. The level of Bcgst1 mRNA expression during infection of tomato leaves parallels the level of actin mRNA. The role of the Bcgst1 gene in the virulence of Botrytis cinerea was evaluated by constructing gene disruption mutants. Three independent disruption mutants were obtained. The virulence of two mutants on tomato leaves was evaluated. Neither of the mutants showed a decrease in virulence, indicating that the Bcgst1 gene is not essential for virulence on tomato leaves under the conditions tested.
The distribution and expression of a biotrophy‐related gene,CIH1, within the genusColletotrichum
Authors: Perfect Sarah E. , Pixton Katherine L. , O’Connell Richard J. , Green Jonathan R. 
Published: March 2003

AbstractDuring the biotrophic phase of the infection process of the hemibiotrophic anthracnose fungusColletotrichum lindemuthianum, an intracellular hypha develops within epidermal cells of its host,Phaseolus vulgaris. This is followed by the formation of secondary hyphae during the necrotrophic phase. Previous work using a monoclonal antibody, UB25, has identified a glycoprotein that is specific to the interfacial matrix that forms between the wall of the intracellular hypha and the invaginated host plasma membrane. The gene encoding the protein identified by UB25 was cloned by immunoscreening and designatedCIH1. The predicted amino acid sequence revealed a proline‐rich glycoprotein, and biochemical evidence suggested that it formed a cross‐linked structure at the biotrophic interface. AlthoughCIH1is a fungal gene, its product has several similarities to plant cell wall proteins. In this paper, we have surveyed the distribution and expression ofCIH1within the genusColletotrichum, encompassing both necrotrophic and hemibiotrophic species. The results show that homologues of theCIH1gene are present in all theColletotrichumspecies tested. Northern blot studies of the time course of the infection processin plantahave shown thatCIH1is expressed by bothC. lindemuthianumin bean andC. trifoliiin alfalfa during the biotrophic phase of fungal development. Immunofluorescence labelling of infected epidermal strips with UB25 revealed that the intracellular hyphae formed byC. destructivumas it infects alfalfa were specifically labelled in a similar way to those formed byC. lindemuthianumin bean. Northern and Western analysis showed thatCIH1was also expressed byC. lindemuthianum in vitro, though not constitutively. Overall, the evidence supports a role forCIH1in biotrophy within the genusColletotrichum.
Up‐regulation of the ascorbate‐dependent antioxidative system in barley leaves during powdery mildew infection
Authors: Burhenne Kim , Gregersen Per L. 
Published: March 2003

AbstractThe ascorbate‐dependent antioxidative system was studied in leaves of barley infected with the barley powdery mildew fungus Blumeria graminis f.sp. hordei (Bgh). Increased ascorbate peroxidase (APX) activity was detected upon infection, especially in the compatible interaction. APX activity was determined in epidermal and total leaf tissues. A relatively higher increase in APX activity was found in the epidermis compared to total leaf 72 h after inoculation in the compatible interaction, but the increase was not restricted to the epidermis. Activity assays in native gels and Northern blot hybridization indicated that the increase in APX activity was caused by a cytosolic APX isoform. ‘Inverse Northern blot’ hybridization results with the cDNA of a cytosolic APX supported the relatively higher increase in epidermal APX activity compared to total leaf activity. In the compatible interaction, monodehydroascorbate reductase (MDHAR) activity increased in temporal and spatial patterns similar to that of APX activity. In contrast to this, dehydroascorbate reductase and glutathione reductase activities either decreased or were unaffected by Bgh infection. The increase in APX and MDHAR activities in the compatible interaction continued until severe infection of the leaves. Thus, an up‐regulation of the antioxidative system of the host cells could play a role for maintenance of the biotrophic relationship between Bgh and the barley leaf by preventing proliferating oxidative processes, which would otherwise be harmful to the living plant cell on which the biotrophic powdery mildew fungus depends.
Methionine synthase, a gene required for methionine synthesis, is expressed in planta by Cladosporium fulvum
Authors: Solomon Peter S. , Nielsen Peter Stein , Clark Anthony J. , Oliver Richard P. 
Published: March 2003

AbstractThe nutritional requirements of phytopathogenic fungi growing in planta has to date been largely ignored. We have begun to address this problem by investigating the methionine requirement for the biotrophic pathogen of tomato Cladosporium fulvum during infection. The Met6 gene from Cladosporium fulvum encoding a cobalamin‐independent 5‐methyltetrahydropteroyltriglutamate‐homocysteinemethyltransferase, was cloned by functional yeast complementation. The open reading frame was found to be 2304 bp, containing no introns and encoding a protein of 87 kDa. In vitro Northern analysis demonstrated high levels of Met6 expression in the absence of externally supplied methionine. However in the presence of methionine or in the absence of carbon, expression of Met6 decreased significantly. Analysis of Met6 expression in planta revealed a strong increase during infection suggesting the requirement for methionine synthesis in planta by Cladosporium fulvum. This study demonstrates that Cladosporium fulvum is starving for methionine during infection and thus implies the essentiality of primary biosynthetic pathways to the infecting fungus.
Characterization of Phytophthora infestans genes regulated during the interaction with potato
Authors: Beyer Katinka , Jiménez Sonia Jiménez , Randall Thomas A. , Lam Stephen , Binder Andres , Boller Thomas , Collinge Margaret A. 
Published: March 2003

SUMMARYSuppression Subtractive Hybridization (SSH) was used to search for genes of Phytophthora infestans that are induced during the infection of potato. To avoid having to distinguish the genes of the pathogen from the plant genes involved in defence responses and to isolate the genes involved in the early stages of interaction, mycelium of P. infestans was induced by contact with the host plant and then separated from the plant tissue. A differential cDNA library was generated by SSH that compared such induced mycelium with mycelium incubated in water. The expression of about 100 cDNA fragments from this differential cDNA library was analysed by hybridization of the arrayed PCR products with mRNA from control and induced mycelium. Twenty per cent of them showed increased transcript levels in mycelium within the first 24 h after exposure to a potato leaf. For six of these cDNA clones the elevated expression in response to the potato leaf could be proven by RNA gel blot analysis. Five of these cDNA clones have predicted amino acid sequence homologies to entries in the databases, including an amino acid transporter, a sucrose transporter, a spliceosome‐associated factor, an ABC transporter, and a cell division control protein. We showed that the genes corresponding to these six cDNA clones are differentially regulated during their life. Reliable gene expression analysis of Phytophthora in infected leaf tissue is not possible until c. 48 h post‐infection, but for two of the genes we identified, induction during in planta growth was detectable by RNA gel blot analysis. Therefore the SSH library that we have created provides a basis for the identification of P. infestans genes that are up‐regulated during the interaction with the plant, which could be important for pathogenicity.
A Delphi survey of research priorities and identified areas for collaborative research in health sector library and information services UK
Authors: Dwyer Maureen 
Published: March 2003

The survey aims were to determine research priorities in the Health Library and Information Services sector in the United Kingdom as to their perceived value for the professional and impact on user needs and to identify areas suitable for collaborative research.A 34‐member panel consisting of the Chairs of professional groups, journal editors, educationalists, key organizations and representatives from the Health Libraries Group, Libraries for Nursing and University Health Science Libraries professional groups, participated in a three‐round postal questionnaire survey using the Delphi Technique.Consensus was achieved for a final set of 20 research priorities. The priorities and their category groups are discussed in the context of (i) the current R&D scene, and (ii) the health information environment. Six developmental recommendations are provided.
Medical information provision in Seychelles: development, current state and future focus
Authors: Stokes Peter John 
Published: March 2003

AbstractMedical information in Seychelles is provided by a library and documentation unit within the Ministry of Health. This unit has been in operation for 10 years and during this time has expanded in the number and type of services provided. This short report describes the current situation at the library and the vision for the next 10 years.
Congenital acinar dysplasia: a rare cause of pulmonary hypoplasia
Authors: Davidson  , Batman  , Fagan  
Published: March 2003

Aims:To describe a third case of congenital pulmonary acinar dysplasia, comparing its clinicopathological features with those of the two previous cases and with cystic adenomatoid malformations.Methods and results:An externally normal female infant was born to a 25‐year‐old after a normal pregnancy. Ventilation was not established. At autopsy the hypoplastic lungs showed bronchial development but no acinar development, resembling the pseudoglandular phase of 16 weeks gestation. As in the previous cases the infant was female, born at term with unaffected older sibling(s); however, no intrapulmonary haematopoietic tissue was identified in the present case. Cystic adenomatoid malformations also resemble microscopically the pseudoglandular phase but are focal pulmonary hyperplasias rather than generalized pulmonary hypoplasias.Conclusion:Congenital acinar dysplasia is a rare, apparently sporadic lethal developmental defect resulting in pulmonary hypoplasia due to failure of lung development beyond the pseudoglandular phase seen at 16 weeks gestation.
Orthokeratinized odontogenic cyst: a clinicopathological and immunocytochemical study of 15 cases
Authors: Li  , Kitano  , Chen  , Itoh  , Kawashima  , Sugihara  , Nozoe  , Mimura  
Published: March 2003

Aims:Intraosseous jaw cysts with a solely orthokeratinized lining epithelium have been suggested to differ from the typical odontogenic keratocysts (OKC) by exhibiting a less aggressive behaviour. We report 15 cases of such cyst type under the term of ‘orthokeratinized odontogenic cyst (OOC)’ and compared their clinical, histological and immunocytochemical features with that of OKC.Methods and results:The cysts of the present series were all solitary lesions, occurred mostly in young male patients, and showed a predilection for the posterior mandible areas. Follow‐up of 14 patients, nine of whom were treated by simple enucleation, revealed no recurrence over a period of 3.5–12 years after surgery. None of the patients had any association with the naevoid basal cell carcinoma syndrome. Furthermore, histological and immunocytochemical comparison between OOC and OKC revealed marked differences in their morphology and epithelial expression. The lining epithelium of OOC lacked the typical features of OKC and appeared to show a lower proliferative activity.Conclusion:These findings suggest that OOC is clinicopathologically separate from other types of odontogenic cysts and may thus constitute a distinct clinical entity.
Primary intestinal gamma‐delta T‐cell lymphoma with evidence of Epstein–Barr virus
Authors: Lavergne  , Brochériou  , Delfau  , Copie‐Bergman  , Houdart  , Gaulard  
Published: March 2003

Aims:Primary intestinal T‐cell lymphomas account for about 5% of all primary gastrointestinal lymphomas and are mostly associated with coeliac disease. They usually express the CD3‐associated T‐cell receptor α/β heterodimer and HML1, and some are related with Epstein–Barr virus (EBV). As far as we know, the present report describes the first case of primary gamma‐delta (γδ) EBV‐associated intestinal T‐cell lymphoma without enteropathy. Only hepatosplenic, nasal and cutaneous γδ T‐cell lymphomas have previously been described.Methods and results:Our case concerned a 43‐year‐old man with no history of coeliac disease, who presented with multifocal small bowel involvement showing high grade T‐cell lymphoma with medium sized and large pleomorphic cells and a small pleomorphic T‐cell component. Angioinvasion and angiocentricity were occasionally present. Immunohistochemical studies of lymphoma cells showed a T‐cell γδ phenotype (CD3+, CD2+, TCRδ1+, Vδ2+ and βF1–) without expression of CD4, CD8, CD5, or HML1. Most tumour cells were positive for the cytotoxic granular proteins TiA1 and granzyme B. Rearrangement of the TCRγ chain gene was demonstrated by polymerase chain reaction and in‐situ hybridization with EBER probes revealed strong nuclear positivity in virtually all neoplastic cells.Conclusion:We described the first case of primary intestinal γδ T‐cell lymphoma without enteropathy in which EBV might fulfil a pathogenic role.
Metallothionein expression in carcinoma of the gallbladder
Authors: Shukla V K , Aryya N C , Pitale A , Pandey M , Dixit V K , Reddy C D , Gautam A 
Published: March 2003

AimsMetallothioneins (MT) are sulphur‐rich, low molecular‐weight, intracellular metal‐binding proteins with a possible role in carcinogenesis of some human tumours. Metallothionein expression in gallbladder cancer has not been studied previously.Methods and resultsImmunohistochemical expression of metallothionein was studied in 42 gallbladders (27 cases of carcinoma of the gallbladder, eight chronic cholecystitis and seven cases of normal gallbladder). Metallothionein expression was significantly higher in cases with carcinoma of the gallbladder (70.37%) as compared to chronic cholecystitis (25%) and normal gallbladders (0%). There was a trend suggestive of increasing MT expression with increasing histological dedifferentiation of carcinoma of the gallbladder.ConclusionsThe increased expression of MT in cases of carcinoma of the gallbladder may represent an increased exposure to heavy metals, which are known carcinogens, and may have a role in gallbladder carcinogenesis. Metallothionein over‐expression in carcinoma of the gallbladder may be relevant to the poor prognosis and chemoresistance seen in these cases.
High metallothionein expression is associated with features predictive of aggressive behaviour in endometrial carcinoma
Authors: McCluggage  , Maxwell  , Hamilton  , Jasani  
Published: March 2003

AimsMetallothioneins (MTs) are a group of ubiquitous low molecular weight proteins with a high affinity for heavy metal ions. The aim of the present study was to investigate MT expression in a series of endometrial carcinomas. We wished to determine whether MT expression in endometrial carcinoma was related to established prognostic factors such as tumour grade, stage and histological type. We also wanted to establish if high MT expression in curettings of endometrial carcinoma was predictive of high expression in the subsequent hysterectomy specimen.Methods and resultsSixty‐three cases of endometrial carcinoma were included in the study. These comprised 57 endometrioid adenocarcinomas (15 grade 1, 25 grade 2, 17 grade 3), three papillary serous adenocarcinomas, two mucinous adenocarcinomas and one clear cell adenocarcinoma. Forty‐five tumours were stage I, 10 were stage II and eight were stage III. In 28 cases, diagnostic endometrial curettings, performed prior to hysterectomy, were available for study. Immunohistochemical staining was performed using the anti‐MT monoclonal antibody E9. The intensity and distribution of MT staining were assessed using a semiquantitative method. This resulted in an intensity distribution (ID) score out of a maximum of 300. The mean ID score of grade 1 and 2 endometrioid adenocarcinomas was 67 and 63, respectively, while for grade 3 tumours the mean ID score was 114. This was statistically significant (P = 0.05). The three papillary serous adenocarcinomas had high ID scores with a mean of 208. The mean ID score of stage I tumours was 69. This was lower than those of stage II and III tumours which had mean ID scores of 116 and 128, respectively. However, these differences were not statistically significant (P = 0.288). A significant correlation was observed between MT ID scores in endometrial curettings and in the subsequent hysterectomy (P = 0.013).ConclusionsMT isoforms can be demonstrated in most endometrial adenocarcinomas. High MT ID scores are associated with high grade and high stage endometrial adenocarcinomas and with the aggressive papillary serous adenocarcinoma. Whether this is of value as an independent prognostic factor has yet to be established.