bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cell‐specific expression of salicylate hydroxylase in an attempt to separate localized HR and systemic signalling establishing SAR in tobacco
Authors: Darby Robert M. , Maddison Anne , Mur Luis A. J. , Bi Yong‐Mei , Draper John 
Published: March 2003

AbstractThere is conflicting evidence concerning the nature of the long‐distance signal responsible for establishing the systemic acquired resistance (SAR) state following a local response to an incompatible plant/pathogen interaction. We outline standard inoculation procedures and terminology for experiments used to characterize SAR in Nicotiana tabacum and show that leaf development (age) has dramatic affects on TMV lesion size which needs to be taken into account in experimental design. TMV infection was more efficient at inducing SAR than primary infection with avirulent bacteria. We have examined the effect on SAR induction of altering the accumulation of salicylic acid (SA), through the expression of a salicylate hydroxylase gene (SH‐L), in different phases of lesion development using the hydrogen peroxide‐responsive AoPR1 promoter and the salicylate‐responsive PR1a promoter. Suppression of SA accumulation during the early phases of lesion development in AoPR1‐SH‐L transgenic tobacco resulted in an attenuated form of SAR compared to wild‐type plants, whereas SAR was not exhibited in PR1a‐SH‐L plants. However, interpretation of data from these experiments was complicated by virus escape from inoculated leaves. Using a GUS reporter it was discovered that the CaMV35S promoter was not expressed constitutively in all cell types of petioles and stems, particularly phloem tissue, whereas the PR1a promoter demonstrated induced expression in the phloem following TMV infection. We suggest two hypotheses for why PR1a‐SH‐L transgenics do not display SAR: either the systemic expression of PR1a‐SH‐L is sufficient to suppress SAR, or SA synthesis or translocation in the phloem is essential for SAR.
Nematodes as vectors to introduce Agrobacterium into plant roots
Authors: Karimi M. , Van Montagu M. , Gheysen G. 
Published: March 2003

SummaryA fast plant promoter test was developed by means of a nematode to transfer Agrobacterium tumefaciens into plant roots. Two‐week‐old Arabidopsis thaliana (L.) Heynh. plants were transferred to infection medium. Meloidogyne incognita or Heterodera schachtii juveniles were mixed with the Agrobacterium strain that harboured the binary vector, and this mixture was used for plant inoculation. During migration of the nematode and establishment of the feeding site inside the roots, the T‐DNA was delivered into the root cells. A few days later, the infected plants could be analysed for expression of the T‐DNA reporter gene in and around the nematode feeding sites (NFS), without the need to go first through the whole transformation and regeneration procedure. Depending on the construct, expression of the β‐glucuronidase gene in the NFS or along the migration path of the nematode could be seen in the roots of Arabidopsis plants. Furthermore, stably transformed plants could be regenerated from the infected roots.
Requirements for cell‐to‐cell movement of Barley stripe mosaic virus in monocot and dicot hosts
Authors: Lawrence Diane M. , Jackson A. O. 
Published: March 2003

SummaryThe Barley stripe mosaic virus (BSMV) RNAß genome contains a series of overlapping open reading frames termed the triple gene block. The three most abundant proteins, βb, βc and βd, have been shown to have essential roles in infectivity, but their function in cell‐to‐cell movement has not previously been unambiguously defined, nor has the role of a minor translational read‐through protein, βd′ been characterized. We have now examined the direct involvement of each of these proteins in cell‐to‐cell movement in planta by engineering fusions of the green fluorescent protein (GFP) to a cysteine‐rich regulatory protein designated γb. Microscopic examination of inoculated and systemically infected barley and oat leaves revealed high levels of fluorescence that moved rapidly through the compact striate vascular tissue without infecting epidermal cells. In contrast, a radial pattern of fluorescence spread through a large number of epidermal and mesophyll cells before entry into the reticulate vascular tissue of the dicot hosts Nicotiania benthamiana and Chenopodium amaranticolor. Mutational analyses indicated that the βb, βc and βd proteins are each essential for cell‐to‐cell movement in local lesion and systemic hosts, whereas the βd′ protein is dispensable. Collectively, these results demonstrate conclusively that the three major triple gene block‐encoded proteins act in concert to mediate cell‐to‐cell movement of BSMV.
Specific recognition of AVR4 and AVR9 results in distinct patterns of hypersensitive cell death in tomato, but similar patterns of defence‐related gene expression
Authors: Cai Xinzhong , Takken Frank L. W. , Joosten Matthieu H. A. J. , De Wit Pierre J. G. M. 
Published: March 2003

SummaryHypersensitive cell death occurs in tomato seedlings that are derived from a cross between plants that express a resistance (Cf) gene against the pathogenic fungus Cladosporium fulvum and plants that contain the matching avirulence (Avr) gene originating from this fungus. The pattern of Cf‐9/Avr9‐ and Cf‐4/Avr4‐induced necrosis in these F1 seedlings was found to differ significantly. Macroscopic observation revealed that in F1 tomato seedlings containing both Cf‐9 and Avr9, numerous necrotic spots developed that were scattered over the entire cotyledon, while the midvein and primary veins remained unaffected. In seedlings containing both Cf‐4 and Avr4, however, initially only one or a few necrotic spots developed on each cotyledon, in most cases in the midvein and occasionally in primary veins. Subsequently, these spots turned rapidly into lesions that enlarged along the midvein and primary veins, eventually causing the cotyledons to wilt and abscise. These observations were confirmed by detailed histological studies. Production of the AVR proteins in adult tomato plants carrying the matching Cf gene, employing potato virus X, resulted in similar patterns of necrosis. RNA gel blot analysis demonstrated that both Avr4 and Avr9, controlled by the CaMV 35S promoter, were highly expressed in seedlings already at one day post‐emergence, indicating that the distinct necrotic patterns are not due to differences in Avr expression levels. We have analysed the expression of many genes involved in defence signalling pathways and the defence response itself, during the onset of the Cf/Avr‐initiated hypersensitive response (HR). Although most of the genes were expressed stronger and faster in Cf‐4/Avr4 seedlings than in Cf‐9/Avr9 seedlings at the onset of HR, no significant qualitative differences in the expression of genes involved in downstream signalling were observed when Cf‐4/Avr4‐ and Cf‐9/Avr9‐induced defence responses were compared.
Tobacco mosaic virus, not just a single component virus anymore
Authors: Knapp Elisabeth , Lewandowski Dennis J. 
Published: March 2003

SummaryTaxonomy: Tobacco mosaic virus (TMV) is the type species of the Tobamovirus genus and a member of the alphavirus‐like supergroup. Historically, many tobamoviruses are incorrectly called strains of TMV, although they can differ considerably in sequence similarities and host range from each other and from TMV.Physical properties: TMV virions are 300 × 18 nm rods with a central hollow cavity (Fig. 1) and are composed of 95% capsid protein (CP), and 5% RNA. Each CP subunit interacts with 3‐nts in a helical arrangement around the RNA. Virions are stable for decades; infectivity in sap survives heating to 90 °C.Electron micrograph of TMV virions stained with uranyl acetate. Courtesy of Dr J.N. Culver, University of Maryland Biotechnology Institute.imageHosts: The natural host range of TMV is limited; however, a broad range of weed and crop species, mostly Solanaceae that includes tobacco, pepper and tomato can be infected experimentally [Holmes, F.O. (1946) A comparison of the experimental host ranges of tobacco etch and tobacco mosaic viruses. Phytopathology, 36, 643–657]. TMV distribution is worldwide. No biological vectors are known.Useful website: http://www.ncbi.nlm.nih.gov/ICTVdb/ICTVdB/71010001.htm
Functional analysis of an extracellular catalase of Botrytis cinerea
Authors: Schouten Alexander , Tenberge Klaus B. , Vermeer Joop , Stewart Jenny , Wagemakers Lia , Williamson Brian , Van Kan Jan A. L. 
Published: March 2003

SummaryThere is evidence that the necrotrophic fungal pathogen Botrytis cinerea is exposed to oxidative processes within plant tissues. The pathogen itself also generates active oxygen species and H2O2 as pathogenicity factors. Our aim was to study how the pathogen may defend itself against cellular damage caused by the accumulation of H2O2 and the role of an extracellular catalase in its detoxification during the infection of tomato and bean plants by B. cinerea. Chloronaphthol staining followed by light microscopy showed that H2O2 accumulates in the infection zone in tomato and bean leaves. An extracellular catalase gene (denominated Bccat2) was cloned from B. cinerea. Exposure of mycelium to H2O2 in liquid culture resulted in increased Bccat2 mRNA levels in a concentration‐dependent manner. Bccat2 mRNA was detected at early stages of tomato leaf infection, suggesting that B. cinerea experiences oxidative stress. Bccat2‐deficient mutants were generated by transformation‐mediated gene disruption. Mutants were more sensitive then the wild‐type strain to H2O2in vitro, but they partly compensated for the absence of BcCAT2 by activating other protective mechanisms in the presence of H2O2. Bccat2‐deficient mutants did not display a consistent reduction of virulence on bean and tomato leaves. Cerium chloride staining of infected leaf tissue for ultrastructural studies showed that Bccat2‐deficient mutants were exposed to H2O2 comparably to the wild‐type. The results suggest that B. cinerea is a robust pathogen adapted to growing in hostile oxidizing environments in host tissues.
Changes in the microflora of manouri, a traditional Greek whey cheese, during storage
Authors: Lioliou K , Litopoulou‐Tzanetaki E , Tzanetakis N , Robinson R K 
Published: March 2003

Six batches of manouri cheese were manufactured, and selected microbial groups were counted throughout storage for 20 days at 4°C. The counts of all the microbial groups increased ( P < 0.05) throughout storage and reached higher levels in cheeses made in summer than in those made in spring. Moreover, the micro‐organisms developed better on the cheese surfaces than in the interiors, especially in summer. The pH (6.78–7.33) and salt‐in‐moisture content (2.53–3.72) of the cheeses did not seem to affect the growth of the bacteria and yeasts present. The isolates of enterobacteriaceae were mainly Hafnia (68.75%), while the isolates from the Baird–Parker medium were mainly staphylococci. There was a great diversity of yeast species, but

Debaryomyces hansenii and

Pichia membranefasciens predominated. The isolates of enterobacteriaceae, staphylococci and—to a lesser extent—yeasts were proteolytic, but the free amino acid (N‐NH2) content of the cheese did not increase significantly during storage (136.4–225.2 mg/kg glycine equivalent). It also seemed that milk fat was not degraded to any great extent (acid degree value 0.09–0.19) by the lipolytic activity of the strains. The main enzymes detected in selected isolates of enterobacteriaceae were leucine aminopeptidase and phosphohydrolase.
African Index Medicus—a cooperative undertaking
Authors: Shaw Jean , Petrak Jelka , BERTRAND IRENE , HUNTER LUCILDA 
Published: March 2003

Although Medline covers many of the significant medical periodical articles published in developed countries, there is still a considerable amount of medical and health documentation from countries outside the major industrialized areas which is not included. This paper outlines various initiatives to address this, and goes on to describe the setting up, on a cooperative basis, of the African Index Medicus, the problems encountered and progress made.‘Even if we should presume that most of the world's valid, important biomedical information originates in the West—and there is evidence (…) to suggest that this is wilful self delusion—what about at least a minority contribution from the rest? The 2% participation in international scientific discourse allowed by Western indexing services is simply too little to account for the scientific output of 80% of the world.’1
The information needs of doctors‐in‐training: case study from the Cairns Library, University of Oxford
Authors: Forrest Maureen , Robb Margaret 
Published: March 2003

AbstractThe objective of this study was to find out more about the information needs of doctors‐in‐training and to identify their preferred sources of information. The methodology included interviews with consultants and administrators, a focus group discussion with library staff and a postal questionnaire sent to 347 doctors‐in‐training (there was a 43% return). The shortcomings of a questionnaire primarily composed of closed questions were addressed by the inclusion of one‐to‐one interviews which offered the opportunity for more in‐depth commentary on specific issues highlighted in the questionnaire.Results indicated the frequency with which various types of information sources were consulted and how this related to the ‘ease of access’ of each information source. There was also the opportunity to comment on future information needs. It was clear from the interviews as well as comments made on the questionnaire that the two most important requirements for doctors‐in‐training were ‘more time to find and obtain information’ and ‘better access to information sources when and where they are needed’. The results, although not surprising, included specific suggestions that have been used for the strategic planning of the library service to deliver the best possible support to users within the current framework of evidence‐based medicine.
Intrathyroidal epithelial thymoma (ITET)/carcinoma showing thymus‐like differentiation (CASTLE) exhibits CD5 immunoreactivity: new evidence for thymic differentiation
Authors: Dorfman  , Shahsafaei  , Miyauchi  
Published: March 2003

Aims:Cases of intrathyroidal epithelial thymoma (ITET)/carcinoma showing thymus‐like differentiation (CASTLE) were examined for CD5 immunoreactivity, a feature of true thymic carcinoma, but not other thymic epithelial neoplasms or carcinomas of other sites. ITET/CASTLE, a rare, low‐grade malignant neoplasm arising within the thyroid gland which resembles lymphoepithelioma‐like and squamous cell carcinoma of the thymus, is postulated to arise from remnants of branchial pouch capable of thymic differentiation, but thymic differentiation in this neoplasm remains unproven.Methods and results:The largest published series of cases of ITET/CASTLE was examined for CD5 immunoreactivity using an anti‐CD5 antibody reactive in fixed, paraffin‐embedded tissue with microwave antigen retrieval. Neoplastic cells in all five cases of ITET/CASTLE studied were immunoreactive for CD5, including foci of tumour metastatic to lymph node and lung. In contrast, none of five cases of thyroid carcinoma with squamous differentiation was immunoreactive for CD5. A minority of cases of typical thyroid carcinomas showed some weak immunoreactivity for CD5. Other carcinomas of the head and neck were non‐immunoreactive for CD5.Conclusions:CD5 immunoreactivity in ITET/CASTLE is new evidence in support of thymic differentiation in this neoplasm.
Loss of CD44 variant 6 expression differentiates small cell carcinoma of urinary bladder from urothelial (transitional cell) carcinoma
Authors: Iczkowski  , Shanks  , Bostwick  
Published: March 2003

Aims:Small cell carcinoma of the urinary bladder has a more aggressive biological potential than urothelial carcinoma, but its morphology may overlap with poorly differentiated urothelial carcinoma. The CD44 family of glycoproteins mediates cell–cell and cell–matrix adhesion. Aberrant regulation of expression of CD44, and particularly its v6 variant exon, has been correlated with aggressive or metastatic phenotype of some cancers. We measured the degree of protein expression of CD44v6 in small cell and urothelial bladder carcinoma.Methods and results:Immunohistochemical staining was performed with monoclonal antibodies against CD44v6. Immunoreactivity was absent in 25 of 27 cases of small cell carcinoma, with two showing only weak staining of fewer than 10% of cells. In contrast, all 12 cases of moderately or poorly differentiated urothelial carcinoma displayed moderately intense reactivity in 50% to 100% of cells.Conclusions:CD44v6 immunostaining discriminates cases of poorly differentiated urothelial carcinoma from small cell carcinoma. It also highlights the presence of mixed small cell urothelial differentiation when present.
Vascular endothelial cadherin is expressed by perineurial cells of peripheral nerve
Authors: Smith  , Jones  , Hilton  
Published: March 2003

AimsTo study the distribution of vascular endothelial (VE) cadherin in peripheral nerves.Methods and resultsUsing two monoclonal antibodies that detect VE‐cadherin (TEA1.31 and 7B4) an immunohistochemical study of VE‐cadherin expression in five common peroneal nerve biopsies and five skin specimens containing small peripheal nerves was performed. VE‐cadherin was consistently expressed by the perineurium of nerves but not by other nerve elements such as Schwann cells or axons.ConclusionThis report indicates that VE‐cadherin is not, as was previously thought, a specific marker of endothelial cells and further defines the phenotype of the perineurial cell. The established role of VE‐cadherin in controlling the permeability of vascular endothelium suggests that this molecule may have a similar role in the perineurium. VE‐cadherin may therefore be important in the maintenance of the blood–nerve barrier, the peripheral nerve equivalent of the blood–brain barrier.
Apoptosis in nasopharyngeal carcinoma as related to histopathological characteristics and clinical stage
Authors: Harn H J , Hsieh H F , Ho L I , Yu C P , Chen J H , Chiu C C , Fan H C , Lee W H 
Published: March 2003

AimsWe investigated the significance of apoptosis, using the terminal deoxynucleotidyl transferase mediated dUTP‐digoxigenin nick end‐labelling method, in nasopharyngeal carcinoma biopsy samples.Methods and resultsThe apoptotic index (AI) in 50 nasopharyngeal carcinomas was compared with various histopathological features and clinical stage. Also, the AI was correlated with p53, bcl‐2 and Ki67 expression by immunohistochemistry. In histopathological studies, the AI was significantly higher in mixed cellular type (MC) than in keratizing squamous cell type (KS) and spindle cell type (SC) (P < 0.001) which worsens prognosis. In tumour stage analyses, AI was higher in early stage (stage 2 and 3) than in high stage (stage 4). In addition, there was a significant correlation between the AI and p53 expression (P < 0.001) but not with proliferative activity (P = 0.15). In NPC containing p53 protein positive tumour cells, there was a significantly higher apoptotic rate.ConclusionsThese findings indicate that apoptosis is related to type and stage of nasopharyngeal carcinoma. They also confirm the role of p53 in regulating tumour apoptosis.
Expression and subcellular localization of human AP endonuclease 1 (HAP1/Ref‐1) protein: a basis for its role in human disease
Authors: Kakolyris  , Kaklamanis  , Giatromanolaki  , Koukourakis  , Hickson  , Barzilay  , Turley  , Leek  , Kanavaros  , Georgoulias  , Gatter  , Harris  
Published: March 2003

Aims: Human AP endonuclease 1 (HAP1) plays a major role in the repair of apurinic/apyrimidinic (AP) sites in cellular DNA by catalysing hydrolytic cleavage of the phosphodiester backbone 5′ to the site. HAP1 is also known to be a potent reduction–oxidation (redox) factor, regulating the binding activity of a number of transcription factors. The purpose of the present study was to examine the expression of HAP‐1 in a wide range of human tissues.Methods and resultsUsing a recently developed specific rabbit polyclonal antibody, we performed immunohistochemistry on paraffin‐embedded tissue material. Nuclear staining was detected in crypt cells of the small and large intestine, epithelial cells of breast ducts, basal cells of the skin, alveolar cells of the lung, lymphocytes of the marginal zone of the spleen, in the surface epithelium and stromal cells of the ovary and the transitional epithelium of the bladder. Unexpectedly for a presumed nuclear protein, the staining pattern in some cell populations was mainly cytoplasmic (e.g. superficial cells of gastrointestinal tract, Langerhans cells, Leydig cells and spermatocytes, epithelium of the prostate glands), or both cytoplasmic and nuclear (e.g. epithelial cells of thymus, follicular thyroid cells, parietal cells of the stomach, glandular epithelial cells of the cervix, epithelial cells of exocrine pancreas).ConclusionThis differential expression in a wide spectrum of cells is indicative of a potential multifunctional action of HAP1, not necessarily restricted to a role in the nucleus.
Cystic partially differentiated nephroblastoma in an adult: an immunohistochemical, lectin histochemical and ultrastructural study
Authors: Nagao T , Sugano I , Ishida Y , Tajima Y , Masai M , Nagakura K , Matsuzaki O , Kondo Y , Nagao K 
Published: March 2003

AimsCystic partially differentiated nephroblastoma (CPDN) is an uncommon renal multicystic tumour, usually affecting early infants. To our knowledge, this report describes the first case of CPDN occurring in an adult.Methods and resultsA 45‐year‐old man was found incidentally to have a left renal cystic tumour, measuring 20 mm in diameter, at the lower pole far from the pelvis. The tumour was composed of multilocular cystic spaces of variable size and intervening septa without solid nodular areas. The cysts were lined by a single layer of flattened, hobnail, or columnar epithelium. The septa were made of mesenchymal cells, which were admixed with small numbers of loosely aggregated blastemal cells, occasional tubular structures in various stages of development, and a few glomeruloid structures. The tumour cells had no anaplasia, and mitoses were rare. Immunohistochemical and lectin histochemical studies revealed that the cyst lining epithelium and the tubular structures in the septa expressed predominantly the markers for distal tubules and collecting ducts. Ultrastructurally, the cyst lining cells closely resembled collecting duct cells while some tubular structures showed an immature nephrogenic morphology. The patient was alive and well without evidence of recurrence 11 months after surgery.ConclusionsCPDN does occur in adults, as experienced in Wilms' tumour, though its incidence is extremely low. This study suggests that CPDN may show maturation intermediate between cystic nephroma and Wilms' tumour, even in adult cases.