bluuebunny/crossref_metadata_2025 huggingface dataset:
Turnip yellow mosaic virus: transfer RNA mimicry, chloroplasts and a C‐rich genome
Authors: DREHER THEO W.
Published: August 2004

Taxonomy:  Turnip yellow mosaic virus (TYMV) is the type species of the genus Tymovirus, family Tymoviridae. TYMV is a positive strand RNA virus of the alphavirus‐like supergroup.

Physical properties:  Virions are non‐enveloped 28‐nm T = 3 icosahedrons composed of a single 20‐kDa coat protein that is clustered in 20 hexameric and 12 pentameric subunits. Infectious particles and empty capsids coexist in infected tissue. The genomic RNA is 6.3 kb long, with a 5′m7GpppG cap and a 3′ untranslated region ending in a tRNA‐like structure to which valine can be covalently added. The genome has a distinctive skewed C‐rich, G‐poor composition (39% C, 17% G).

Viral proteins:  Two proteins, whose open reading frames extensively overlap, are translated from the genomic RNA. p206, which contains sequences indicative of RNA capping, NTPase/helicase and polymerase activities, is the only viral protein that is necessary for genome replication in single cells. It is produced as a polyprotein and self‐cleaved to yield 141‐ and 66‐kDa proteins. p69 is required for virus movement within the plant and is also a suppressor of gene silencing. The coat protein is expressed from the single subgenomic RNA.

Hosts and symptoms:  TYMV has a narrow host range almost completely restricted to the Cruciferae. Experimental host species are Brassica pekinensis (Chinese cabbage) or B. rapa (turnip), in which diffuse chlorotic local lesions and systemic yellow mosaic symptoms appear. Arabidopsis thaliana can also be used. Clumping of chloroplasts and the accumulation of vesicular invaginations of the chloroplast outer membranes are distinctive cytopathological symptoms. High yields of virus are produced in all leaf tissues, and the virus is readily transmissible by mechanical inoculation. Localized transmission by flea beetles may occur in the field.
Homologous soybean and Arabidopsis genes share responsiveness to cyst nematode infection
Authors: MAZAREI MITRA , LENNON KRISTEN A. , PUTHOFF DAVID P. , RODERMEL STEVEN R. , BAUM THOMAS J.
Published: August 2004

We previously isolated a partial soybean cDNA clone (D17.1) whose corresponding transcript increases in susceptible roots 1 day post inoculation (dpi) with the soybean cyst nematode, Heterodera glycines. Here we isolated the corresponding full‐length cDNA from a soybean cDNA library and designated this gene of unknown function Gm17.1. Time course RNA gel blot analyses revealed that Gm17.1 mRNA steady‐state levels were elevated in soybean roots following H. glycines infection up to at least 6 dpi. For further in‐depth study we identified a homologous Arabidopsis thaliana gene and designated this gene At17.1. Arabidopsis is successfully infected by the sugar beet cyst nematode (H. schachtii), a close relative of H. glycines. We isolated the At17.1 promoter, fused it to the β‐glucuronidase (GUS) reporter gene, and transformed this construct into Arabidopsis plants as well as soybean hairy roots. Histochemical analysis of plant materials containing the At17.1::GUS construct revealed that the At17.1 promoter is functional in Arabidopsis as well as in soybean and that during normal plant development the At17.1 promoter directs GUS expression predominantly to the vascular tissues and root tips of both plant species. When At17.1::GUS Arabidopsis plants and soybean hairy roots were inoculated with cyst nematodes, strong GUS activity was detected within the cyst nematode‐induced feeding structures. Further tests of At17.1 promoter activity in Arabidopsis revealed that this promoter was induced by auxin, jasmonic acid, mannitol and dehydration. Quantitative real‐time reverse transcription‐polymerase chain reaction assays of At17.1 expression confirmed the observed promoter characteristics. Based on our expression data and the observation that both the soybean and the Arabidopsis homologues behaved in a similar fashion following cyst nematode infection, it is likely that these genes are closely associated with cyst nematode parasitism of plants, potentially with hormone and osmotic changes occurring in the developing nematode feeding cells. Furthermore, these data provide additional insights into the strengths of the Arabidopsis–H. schachtii pathosystem to study cyst nematode–plant interactions in lieu of less tractable pathosystems. This finding is supported by the fact that the Arabidopsis promoter tested here produced similar results in Arabidopsis and soybean.
The jasmonate‐insensitive mutant jin1 shows increased resistance to biotrophic as well as necrotrophic pathogens
Authors: NICKSTADT ANJA , THOMMA BART P. H. J. , FEUSSNER IVO , KANGASJÄRVI JAAKKO , ZEIER JUERGEN , LOEFFLER CHRISTIANE , SCHEEL DIERK , BERGER SUSANNE
Published: August 2004

Jasmonic acid and related oxylipin compounds are plant signalling molecules that are involved in the response to pathogens, insects, wounding and ozone. To explore further the role of jasmonates in stress signal transduction, the response of two jasmonate‐signalling mutants, jin1 and jin4, to pathogens and ozone was analysed in this study. Upon treatment with the biotrophic bacterial pathogen Pseudomonas syringae, endogenous jasmonate levels increased in jin1 and jin4 similar to wild‐type, demonstrating that these mutants are not defective in jasmonate biosynthesis. Jin1 but not jin4 is more resistant to P. syringae and this higher resistance is accompanied by higher levels of salicylic acid. Jin1 is also more resistant to the necrotrophic fungal pathogen Botrytis cinerea and shows wild‐type sensitivity to ozone whereas jin4 is more susceptible to B. cinerea and ozone. These results indicate that the mutations in jin1 and jin4 affect different branches of the jasmonate signalling pathway. Additionally, in this combination of phenotypes, jin1 is unique among all other jasmonate‐related mutants described thus far. These data also provide support for a crosstalk between the jasmonate and salicylate pathways.
Pathogen‐induced resistance and alarm signals in the phloem
Authors: VAN BEL AART J. E. , GAUPELS FRANK
Published: August 2004

Despite a long‐standing notion of long‐distance signals triggering systemic acquired resistance (SAR), the translocation pathway and the identity of the signals involved have not been determined with any degree of certainty. A critical assessment indicates that, in parallel to signalling via the phloem, alternative modes for SAR induction such as signalling via the xylem or air‐borne signalling by volatile substances may occur. This review further evaluates several classes of compounds as being functional in systemic resistance signalling. Evidence in favour of SAR involvement of phloem‐mobile substances such as salicylic acid, lipid‐derived molecules, reactive oxygen species and components of the antioxidant machinery is contradictory, circumstantial or inconclusive, at best. Nitric oxide bound to proteins or thiols seems a good candidate for signalling, but has not been found in phloem sap thus far. No convincing support of the involvement in SAR of phloem‐mobile substances such as calcium, oligosaccharides, peptides or RNA species, which function in other systemic signalling cascades, has yet been produced. Nevertheless, phloem‐mobile macromolecules are considered as potential tools for SAR given their pivotal role in remote gene expression under stress conditions. In this framework, the existence of several cascades for signal generation along the phloem pathway is envisaged. Finally, recent methods for detection of molecular signals in phloem sap and their expression in companion cells are presented.
The AoPR10 promoter and certain endogenous PR10 genes respond to oxidative signals in Arabidopsis
Authors: MUR LUIS A. J. , STURGESS FAYE J. , FARRELL GILLIAN G. , DRAPER JOHN
Published: August 2004

The PR10 class of genes has been associated with plant defence. Previous studies with an asparagus PR10 gene (AoPR1) promoter in heterologous plants suggested that the AoPR10‐GUS transgene was responsive to oxidative signals/stresses. Arabidopsis thaliana AoPR10‐GUS transgenics allowed expression to be compared with that of a close homologue from the large family of PR10 class genes within the Arabidopsis genome. AoPR10‐GUS was induced developmentally at sites of phenylpropanoid accumulation and by wounding, pathogen challenge and treatment with H2O2 but not with salicylic acid (SA), ethylene, methyljasmonate or NO donors. Both wound‐ and pathogen‐associated AoPR10‐GUS expression could be suppressed by superoxide dismutase and the NADPH oxidase inhibitor, diphenylene iodonium. Northern blotting using an Arabidopsis PR10 homologue as a probe revealed transcript up‐regulation by oxidative species generated by glucose oxidase and xanthine oxidase. In Arabidopsis, the AoPR10‐GUS transgene was potentiated by SA and expressed systemically following wounding or challenge with avirulent bacteria. AoPR10‐GUS × npr1‐1 crosses revealed that potentiation and systemic expression was NPR1‐independent. Systemic AoPR10‐GUS expression following elicitation of a hypersensitive response but not wounding was abolished in NahG crosses, suggesting an SA‐mediated potentiating action during SAR (systemic acquired resistance). These data suggest that the AoPR10 promoter reports the expression of reactive oxygen species‐responsive PR10 genes and may indicate systemic changes in oxidative status following either wounding and/or the elicitation of a hypersensitive response in Arabidopsis.
An Arabidopsis mutant with altered hypersensitive response to Xanthomonas campestris pv. campestris, hxc1, displays a complex pathophenotype
Authors: LUMMERZHEIM MARIE , KROJ THOMAS , FERREIRA MARCIO , TRONCHET MAURICE , GODARD FRANÇOIS , VAN MONTAGU MARK , ROBY DOMINIQUE
Published: August 2004

The hxc1 mutant was identified by screening an EMS (ethylmethane sulphonate) mutagenized population of Arabidopsis Col‐0 plants for an altered hypersensitive response (HR), after spray inoculation with an HR‐inducing isolate of Xanthomonas campestris pv. campestris (Xcc) (strain 147). The hxc1 mutant shows a susceptible phenotype several days after initiation of the interaction with the avirulent strain. This macroscopically observed phenotype was confirmed by measurement of in planta bacterial growth and by microscopical analysis. Interestingly, the hxc1 mutation acts very specifically. Hxc1 displays a pathophenotype identical to that observed in the wild‐type with several extensively characterized avirulent and virulent bacteria, except in response to Pseudomonas syringae pv. tomato strain DC3000/avrRpm1, for which a partial loss of resistance was observed. Finally, the mutation causes an attenuation of expression of several defence markers regulated through different signalling pathways. Together, these data underline the complexity of this novel defence mutant, and support the hypothesis of a mutation affecting a key component acting during the first steps of the plant defence response leading to resistance to Xcc147 and Pseudomonas syringae pv. tomato containing the avr gene, avrRpm1.
Downstream targets of the Phytophthora infestans Gα subunit PiGPA1 revealed by cDNA‐AFLP
Authors: DONG WUBEI , LATIJNHOUWERS MAITA , JIANG RAYS H. Y. , MEIJER HAROLD J. G. , GOVERS FRANCINE
Published: August 2004

In many plant pathogens heterotrimeric G‐proteins are essential signalling components involved in development and pathogenicity. In the late blight oomycete pathogen Phytophthora infestans the G‐protein α subunit PiGPA1 controls zoospore motility and is required for virulence. To identify G‐protein targets and signalling pathways downstream of PiGPA1, we used an optimized cDNA‐AFLP protocol for analysing gene expression profiles in hypovirulent P. infestans strains that were previously generated by silencing the Pigpa1 gene. First, expression profiles in sporangia and mycelium of the wild‐type strain were compared, and this revealed a substantial number of mycelium‐ or sporangia‐specific transcript derived fragments (TDFs). Subsequently, profiles in sporangia of wild‐type, Pigpa1‐silenced mutants and of a strain expressing a constitutively active form of PiGPA1 were compared. From a total of 2860 TDFs, 92 were down‐ and 19 up‐regulated in the Pigpa1‐silenced mutants. A subset of the differential TDFs was cloned and sequenced, and homology searches were carried out against Phytophthora EST and genomic databases and the NCBI database. cDNA‐AFLP expression profiles were verified by Northern blot analysis or RT‐PCR. The power of cDNA‐AFLP for the identification of target genes in knock‐down or gain‐of‐function mutants is discussed.
Gastrointestinal side‐effects of traditional non‐steroidal anti‐inflammatory drugs and new formulations
Authors: Lazzaroni M. , Bianchi Porro G.
Published: August 2004

Although adverse effects of non‐steroidal anti‐inflammatory drugs (NSAIDs) occur in only a small proportion of users, the widespread use of these drugs has resulted in a substantial overall number of affected persons who experience serious gastrointestinal complications. Dyspeptic symptoms are estimated to occur in 10–60% of NSAID users and lead to discontinuation of treatment in 5–15% of rheumatoid arthritis patients taking NSAIDs. It is now well established that the point prevalence of peptic ulcer disease in patients receiving conventional NSAID therapy ranges between 10 and 30%, representing a 10–30‐fold increase over that found in the general population. One of 175 users of conventional NSAIDs in the USA will be hospitalized each year for NSAID‐induced gastrointestinal damage. The mortality of hospitalized patients remains about 5–10%, with an expected annual death rate of 0.08%. The selective COX‐II inhibitors (rofecoxib, celecoxib, parecoxib, etoricoxib, valdecoxib, lumiracoxib) show consistently comparable efficacy to that of conventional non‐steroidal anti‐inflammatory drugs (NSAIDs) in patients with rheumatoid arthritis and osteoarthritis, but have a significantly reduced propensity to cause gastrointestinal toxicity. In many cases, the gastric effects of therapeutically active doses of COX‐II inhibitors are indistinguishable from placebo. The safety benefits of COX‐2 inhibitors given alone appear similar to combined therapy with conventional NSAIDs and gastroprotective agents. These findings warrant the consideration of COX‐II inhibitors as first‐line therapy in patients requiring long‐term pain control.
Diagnosis and therapy of irritable bowel syndrome
Authors: De Giorgio R. , Barbara G. , Stanghellini V. , Cremon C. , Salvioli B. , De Ponti F. , Corinaldesi R.
Published: August 2004

Irritable bowel syndrome (IBS) is one of the most common gut functional diseases, affecting 10–20% of people worldwide. Although most patients do not seek medical help, the disease accounts for huge costs for both patients and health‐care systems and worsens significantly patients' quality of life. Diagnosis is based on the identification of symptoms according to Manning, Rome I and Rome II criteria and exclusion of alarm indicators. IBS symptoms overlap with those of coeliac disease, lactose intolerance, food allergies and bile salt malabsorption. The treatment of IBS is centred on an excellent doctor–patient relationship along with drugs targeting the predominant symptom, especially during exacerbations. Current pharmacological remedies are unsatisfactory due to the high number of patients complaining of lack of response and/or symptom recurrence. Although useful in some IBS patients, the validity of psychotherapy deserves further investigation. A wide array of potentially useful drugs are currently under consideration in pre‐clinical trials. A better understanding of the pathogenetic mechanisms underlying IBS may help to develop more effective drugs for this disease.
Non‐steroidal anti‐inflammatory drugs: who should receive prophylaxis?
Authors: Hawkey C. J.
Published: August 2004

Non‐steroidal anti‐inflammatory drugs (NSAIDs) are the major recognized cause of iatrogenic disease, and may cause 100 000 deaths per annum through peptic ulcer complications. A number of risk factors can be identified that indicate patients at high risk. These patients can be managed by substitution of a COX‐2 inhibitor or by prophylaxis with a proton pump inhibitor (PPI). Because risk factors that render patients at high risk of ulcer complications also act in the absence of NSAID use, PPI prophylaxis (or Helicobacter pylori eradication where H. pylori is the risk factor) have much to offer and controlled studies show that the incidence of recurrent peptic ulcer bleeding can be reduced substantially by PPI co‐administration. Substitution of COX‐2 inhibitors also has much to offer, arguably most in those without risk factors (although regulatory authorities do not accept this argument). Recent data show that PPI and COX‐2 inhibitors can play complementary roles in the management of patients with moderate to severe dyspepsia and at high risk of ulcer complications.
What the physician needs to know for correct management of gastro‐oesophageal reflux disease and dyspepsia
Authors: Talley N. J.
Published: August 2004

Upper gastrointestinal symptoms are highly prevalent; usually those consulting have multiple symptoms, confounding management. Here, common clinically relevant management issues are considered based on the best available evidence. Regardless of the presenting symptoms, determine if there are any alarm features; these have a low positive predictive value for malignancy but all patients with them should be referred for prompt upper gastrointestinal endoscopy. Ask about medications; of most importance are the non‐steroidal anti‐inflammatory drugs (NSAIDs), both non‐selective and COX‐2 selective. Try to ascertain if the symptom pattern suggests gastro‐oesophageal reflux disease (GERD) or not. Dominant heartburn, however, may be of limited value; if the background prevalence of GERD is 25% and the patient complains of dominant heartburn, then the likelihood that such a patient has GERD as identified by 24‐h oesophageal pH testing is only just over 50%. If reflux disease is strongly suspected and there are no alarm features, give an empirical trial of a proton pump inhibitor (PPI). Symptoms cannot separate adequately functional from organic dyspepsia. Endoscopy in dyspepsia with no alarm features is more costly than an empirical management approach. H. pylori testing and treatment remains in most settings the preferable initial choice for managing dyspepsia without obvious GERD. However, a PPI trial may offer a similar outcome and may be preferable in low H. pylori prevalence areas; head‐to‐head management trials in primary care are lacking.
Definition and diagnosis in portal hypertension – continued problems with the Baveno consensus?
Authors: De Franchis R.
Published: August 2004

The goals of the Baveno workshops were to develop consensus definitions of key events related to portal hypertension and variceal bleeding, and to produce guidelines to facilitate the conduct and reporting of clinical trials. The consensus definitions concern the diagnosis of active bleeding, failure to control bleeding, the criteria to distinguish continuing bleeding from rebleeding, and the means of assessing failure to prevent rebleeding. The guidelines concern the timing of diagnostic endoscopy, the policy for blood volume restitution, the measures to prevent infection and encephalopathy, and the treatment options for acute bleeding, as well as primary and secondary prophylaxis. The intention of the experts who developed the guidelines was that, as feedback from their practical application develops, they should be adapted to better fit the practical needs. The applicability of the Baveno definitions has been evaluated in a study where the definitions of clinically significant bleeding, failure to control bleeding, the time frame for the acute bleeding episode and the definition of rebleeding were tested. The main criticism raised in this study was that tachycardia, one of the criteria that define failure to control bleeding, was misleading in 15% of patients who had the symptom but were not bleeding.
Prognosis of hepatorenal syndrome – has it changed with current practice?
Authors: Angeli P.
Published: August 2004

The Consensus Conference on Hepatorenal Syndrome (HRS) organized by the International Ascites Club in 1994 redefined HRS, introduced new diagnostic criteria that are now widely accepted, and proposed the distinction between two types of HRS: type 1 and type 2. Before the introduction of the new therapeutic options, the median survival of patients with type 1 HRS was only 1.7 weeks, and 6–12 months in patients with type 2 HRS. Liver transplantation (LT) was the first therapeutic option to change the prognosis of cirrhotic patients with HRS and 5‐year survival after LT in patients with HRS is only slightly less than that of transplanted patients without HRS and markedly increased when compared to survival in nontransplanted patients with HRS. Nevertheless, a large proportion of patients die before LT is possible because of the poor prognosis of HRS and the prolonged waiting times in most transplant centres. Other therapeutic approaches were therefore developed to increase survival in patients with HRS. Vasoconstrictors and transjugular intrahepatic portosystemic shunt (TIPS) are the most promising. The administration of vasoconstrictors together with albumin has been shown to reverse type 1 HRS and even to completely normalize renal function in 60–70% of treated patients. To date, four studies assessing TIPS in the management of type 1 HRS have been reported and TIPS insertion was technically successful in all of them. Given the shortage of donors for LT, vasoconstrictor therapy and TIPS strategies may be considered as a bridge to LT in patients with type 1 HRS.
The actin cytoskeleton is involved in signalling protoplast embryogenesis induced by agarose embedding
Authors: Brière Christian , Barthou Henri , Jauneau Alain , Alibert Gilbert , Petitprez Michel
Published: August 2004

The organization of actin microfilaments was studied by immunofluorescence in protoplasts isolated from sunflower hypocotyls and cultured in an agarose matrix. Removal of the cell wall completely disrupted the actin cytoskeleton, which became progressively reorganized into cortical microfilament arrays and actin cables during protoplast culture. Treatment of protoplasts with arginine‐glycine‐aspartic acid (Arg‐Gly‐Asp) motif‐containing peptides, to inhibit putative cell contacts with the agarose matrix, strongly affected this repair process: microfilament elongation and cable formation were inhibited and the connectivity between the cortical network and the perinuclear basket was lost. Furthermore, embryoid formation induced by agarose embedding was reduced. Similar effects were observed with a short treatment with latrunculin B, known to disrupt actin microfilaments. These results indicate that the actin network is involved in the signalling process that leads to polarity acquisition and embryoid determination in agarose‐embedded protoplasts.
Impaired carotenogenesis can affect organization and functionality of etioplast membranes
Authors: Moro Isabella , Dalla Vecchia Francesca , La Rocca Nicoletta , Navari‐Izzo Flavia , Quartacci Mike Frank , Di Baccio Daniela , Rüdiger Wolfhart , Rascio Nicoletta
Published: August 2004

The effects of impaired carotenogenesis on plastid membrane organization, functionality and stability were studied in etiolated barley plants grown at 20 and 30°C. The plants were treated with norflurazon or amitrole, two herbicides affecting phytoene desaturation and lycopene cyclization, respectively. At 20°C, the amitrole‐treated etioplasts, which accumulated lycopene in their inner membranes, exhibited disorganized prolamellar bodies, containing a prevalent form of non‐phototransformable protochlorophyllide (Pchlide). They also showed a certain difficulty in reducing the phototransformable pigment to chlorophyllide when exposed to light, and were unable to reform the active ternary complex [protochlorophyllide–oxidoreductase (POR)–Pchlide–NADPH] when placed back in darkness. No ultrastructural alterations were found in norflurazon‐treated etioplasts, with carotenogenesis inhibited at the phytoene desaturation step. In these latter organelles, Pchlide, whose forms were comparable with those of the control etioplasts, was photoreduced quickly after illumination and the ternary complex was reformed during a subsequent dark period. Thus, the impaired carotenogenesis leading to the accumulation of lycopene showed greater interference with the etioplast membrane arrangement and functionality than did the earlier interruption of the biosynthetic pathway at the phytoene level. This might be due to the different interactions of the distinct carotenoid precursors with other membrane components. However, in etioplasts of norflurazon‐treated plants, a rise in growth temperature caused a partial demolition of prolamellar bodies, showing a lowered thermostability of the carotenoid‐deficient membranes. This latter effect strengthens the concept that a correct and complete carotenogenesis pathway, leading to the synthesis of polar carotenoids (i.e. xanthophylls), is required for the maintenance of stable plastid membranes.
Apoplastic pH and FeIIIreduction in young sunflower (Helianthus annuus) roots
Authors: Kosegarten Harald , Hoffmann Bernd , Rroco Evan , Grolig Franz , Glüsenkamp Karl‐Heinz , Mengel Konrad
Published: August 2004

The relationship between the apoplastic pH in young sunflower roots (Helianthus annuusL.) and the plasmalemma ferric chelate reductase (FC‐R; EC 1.16.1.7) activity in roots was investigated. The hypothesis was tested that a high apoplastic pH depresses FC‐R activity, thereby restricting the uptake of Fe2+into the cytosol. Until recently, little has been known about this relationship, because pH and redox reaction measurements are difficult to perform within the confines of the root apoplast. We recorded the apoplastic pH by means of the fluorescence ratio in conjunction with video microscopy by covalently tagging fluorescein boronic acid to OH groups of the root cell wall. FeIIIreduction was measured using a similar approach by tagging ferrozine diboronic acid with OH groups of the cell wall. Ferrozine forms an Fe2+complex, thus indicating the reduction of ferric iron. In roots bathing in buffered outer solutions of different pH, a high pH sensitivity of apoplastic FeIIIreduction was found, with the highest ferric iron reduction rates at an apoplastic pH of 4.9; above an apoplastic pH of 5.3, no reduction was observed. Nitrate in the bathing solution increased the apoplastic pH and hence depressed the FeIIIreduction; ammonium had the reverse effect. Nitrate together with HCO3–, a combination which is typical of calcareous soils, had the strongest depressing effect. From the results, it can be concluded that the main reason for the frequently occurring iron deficiency chlorosis of plants grown on calcareous soils is the inhibition of FeIIIreduction in the apoplast, and hence Fe2+uptake into the cytosol.
Analysis of differences in photosynthetic nitrogen‐use efficiency between four contrasting species
Authors: Pons Thijs L. , Westbeek Milka H. M.
Published: August 2004

Causes of differences in photosynthetic nitrogen‐use efficiency (PNUE), the rate of photosynthesis per unit leaf N, were investigated in four species. These were in order of decreasing PNUE; the two herbs Galinsoga ciliata and Origanum vulgare, and the two trees Populus nigra and Quercus robur. Plants were grown in pots outdoors at three levels of nutrient availability. The light‐ and CO2 response of gas exchange of leaves were measured, and their nitrogen and chlorophyll contents were determined. Furthermore, the internal conductance for CO2 diffusion was estimated. Nutrients did not have a large effect on PNUE except in Galinsoga. Leaf mass per unit area was negatively correlated with PNUEmax, which is likely to be partly caused by N present in cell wall proteins among other non‐photosynthetic N compounds. The trees had a larger fraction of photosynthetic N in light harvesting components compared to the herbs. This contributed also substantially to the difference in PNUE at light saturation (PNUEmax) between the two groups, but not for PNUE calculated for an overcast day. Intercellular CO2 concentration was high in Galinsoga and Populus, which contributed significantly to their higher PNUEmax, particularly at low nutrient availability. The large gradient in CO2 concentration between intercellular spaces and chloroplasts was another factor that explained a substantial part of the differences in PNUEmax between Quercus and the other species that had smaller gradients. Stomatal and internal conductances for CO2 explained most of the difference in PNUEmax between Quercus and Populus at high nutrient availability for which these data were available.
Towards transcript profiling of desiccation tolerance in Xerophyta humilis: Construction of a normalized 11 k X. humilis cDNA set and microarray expression analysis of 424 cDNAs in response to dehydration
Authors: Collett Helen , Shen Arthur , Gardner Michael , Farrant Jill M , Denby Katherine J. , Illing Nicola
Published: August 2004

Xerophyta humilis (Bak.) Dur and Schinz is an indigenous Southern African resurrection plant which is able to protect itself from the stresses associated with extreme dehydration. For the purpose of analysing global patterns of gene expression in response to desiccation and recovery on rehydration, we have generated a normalized 10 900 library, representing genes from root and leaf tissue that are expressed during the dehydration‐rehydration cycle. For the small‐scale microarray analysis described here, 424 cDNAs were sequenced, annotated, arrayed and hybridized with hydrated and dehydrated, leaf‐specific RNA. Reverse Northern blots were used as an alternative method to compare the expression results. A total of 55 dehydration‐inducible cDNAs were identified combining the results of both methods. Northern blot analysis of 14 of the 55 the dehydration‐upregulated cDNAs verified the expression status of all 14 genes. Dehydration‐upregulated cDNAs included those homologous to known dehydration stress‐responsive genes encoding metallothioneins, galactinol synthases, an aldose reductase and a glyoxalase. A large number of genes encoding late embryonic abundant proteins (LEAs), dehydrins and desiccation‐related proteins were also identified, suggesting that proteins that provide mechanical and antioxidant protection against water loss dominate the mRNA population in desiccated X. humilis leaf tissue. Dehydration‐upregulated genes identified in this study, and not previously implicated in the dehydration response, include cDNAs encoding a putative chloroplast RNA‐binding protein and a protein containing SNF2/helicase domains. Comparisons with microarray data, which profile the dehydration response in desiccation‐sensitive plants, reveal differences in expression patterns between X. humilis and Arabidopsis and rice that could provide clues as to the mechanisms underlying desiccation‐tolerant and ‐sensitive phenotypes. The X. humilis library promises to be a useful resource for transcript profiling the dehydration and rehydration response in a desiccation‐tolerant plant.
Amino acid export from infected cells ofVicia fabaroot nodules: Evidence for an apoplastic step in the infected zone
Authors: Peiter Edgar , Yan Feng , Schubert Sven
Published: August 2004

In root nodules of leguminous plants, such asVicia fabaL., N2is fixed by rhizobial bacteroids within infected cells. These cells are located in the centre of the nodule, whereas the vascular system serving import and export of solutes is located in the periphery. Within the infected central tissue, metabolites may travel symplastically by using bands of interconnected uninfected cells. Structural evidence, however, speaks against symplastic movement between infected cells themselves. The present work examined the possibility of an apoplastic step in amino acid export from infected cells. Incubation experiments with dissected central tissue demonstrated the release of amino compounds by infected cells. The predominant compound released was asparagine, which is also the major amino acid in xylem sap of legumes forming indeterminate nodules. During incubation of central infected tissue, medium acidification by plasma membrane H+‐ATPase quickly turned into slight alkalization, probably caused by the released amino acids. In vivo, this process would lead to an increased apoplastic pH with consequences for processes relying on the proton gradient across the plasma membrane. Uptake of14C‐labelled amino acids by uninfected and infected cells was studied using protoplasts isolated from the central nodule tissue. Uninfected protoplasts accumulated amino acids with low specificity in a ΔpH‐dependent, bi‐phasic manner, whereas infected protoplasts did not absorb amino acids from the medium. This indicates that uninfected protoplasts not only function in metabolite transport, but also in collection of amino acids from the apoplast. Taken together, both experimental approaches demonstrate the possibility of an apoplastic export step for amino acids in the central tissue of indeterminate legume nodules.
Morphology of proliferating and non‐proliferating tumor cell nuclei in glioblastomas correlates with preoperative data from proton‐MR‐spectroscopy
Authors: Nafe Reinhold , Herminghaus Sebastian , Pilatus Ulrich , Hattingen Elke , Marquardt Gerhard , Schlote Wolfgang , Lanfermann Heinrich , Zanella Friedhelm
Published: August 2004

In contrast to the growing interest in proton‐MR‐spectroscopy (1HMRS) for preoperative examination of patients with brain tumors, there is nearly no knowledge about a correlation between data from 1HMRS and histomorphology as confirmed by quantitative morphological methods. Whether a correlation can be confirmed between data from 1HMRS and quantitative histomorphology of glioblastomas representing the most frequent type of brain tumors was investigated in the present study. Furthermore, it was of interest, whether correlations between spectroscopic data and histomorphology can be confirmed for proliferating and non‐proliferating tumor cell nuclei independently. Using stringent inclusion criteria for this study, 24 patients were investigated by means of preoperative 1HMRS and by means of digital image analysis of paraffin sections from the surgical specimen. Proliferating and non‐proliferating tumor cell nuclei were investigated separately in the region with the highest proliferative activity in each tumor using immunohistological staining for the proliferation marker Ki67. Main results showed highly significant correlations between total creatine and variables of nuclear size, as well as correlations between choline and variables of nuclear shape. These results were confirmed for both proliferating and non‐proliferating tumor cell nuclei. A significant correlation between N‐acetyl‐aspartate level and topometric variables (number of neighbors per nucleus, variables describing distances between tumor cell nuclei) was confirmed for proliferating tumor cell nuclei. Discriminant analysis provided a good separation of cases with high and with low values for these spectroscopic variables based on histomorphometric data. In conclusion, the results confirm a direct correlation between data from preoperative 1HMRS and histomorphological characteristics of glioblastomas supporting the biological relevance of spectroscopic data for the examination of brain tumor patients.
Chordoid meningioma: Rare variant of meningioma
Authors: Özen Özlem , Şar Aylin , Atalay Başar , Altınörs Nur , Demirhan Beyhan
Published: August 2004

Chordoid meningioma is a rare variant of meningioma that bears a striking histological resemblance to chordoma and has greater likelihood of recurrence. Although most meningiomas occur in the intracranial, orbital and intravertebral cavities, rare meningiomas have been reported in extracranial organs; thus, it is important to be able to distinguish them from other neoplasms that have similar histology but different biological behavior and therapies. A case of chordoid meningioma in a 48‐year‐old woman who did not have Castleman's syndrome is described in the present report. The patient presented with a mass in her left frontoparietal region, and had been suffering from headaches for many years. Magnetic resonance imaging of the brain demonstrated an expansive lytic lesion in the squamous portion of the left temporal bone. The lesion extended in both directions. Histological examination of the surgical specimen revealed a tumor composed of cords and nests of eosinophilic vacuolated cells embedded in a myxoid matrix. A typical meningiomatous pattern was observed focally, and positive staining of the tumor cells for vimentin and epithelial membrane antigen confirmed the diagnosis of chordoid meningioma.
Human neural stem cells genetically modified for brain repair in neurological disorders
Authors: Kim Seung U.
Published: August 2004

Existence of multipotent neural stem cells (NSC) has been known in developing or adult mammalian CNS, including humans. NSC have the capacity to grow indefinitely and have multipotent potential to differentiate into three major cell types of CNS, neurons, astrocytes and oligodendrocytes. Stable clonal lines of human NSC have recently been generated from the human fetal telencephalon using a retroviral vector encoding v‐myc. One of the NSC lines, HB1.F3, carries normal human karyotype of 46XX and has the ability to self‐renew, differentiate into cells of neuronal and glial lineages, and integrate into the damaged CNS loci upon transplantation into the brain of animal models of Parkinson disease, HD, stroke and mucopolysaccharidosis. F3 human NSC were genetically engineered to produce L‐dihydroxyphenylalanine (L‐DOPA) by double transfection with cDNA for tyrosine hydroxylase and guanosine triphosphate cylohydrolase‐1, and transplantation of these cells in the brain of Parkinson disease model rats led to L‐DOPA production and functional recovery. Proactively transplanted F3 human NSC in rat striatum, supported the survival of host striatal neurons against neuronal injury caused by 3‐nitropro‐pionic acid in rat model of HD. Intravenously introduced through the tail vein, F3 human NSC were found to migrate into ischemic lesion sites, differentiate into neurons and glial cells, and improve functional deficits in rat stroke models. These results indicate that human NSC should be an ideal vehicle for cell replacement and gene transfer therapy for patients with neurological diseases. In addition to immortalized human NSC, immortalized human bone marrow mesenchymal stem cell lines have been generated from human embryonic bone marrow tissues with retroviral vectors encording v‐myc or teromerase gene. These immortalized cell lines of human bone marrow mesenchymal stem cells differentiated into neurons/glial cells, bone, cartilage and adipose tissue when they were grown in selective inducing media. There is further need for investigation into the neurogenic potential of the human bone marrow stem cell lines and their utility in animal models of neurological diseases.
Cyclooxygenase‐2 in oligodendroglioma: Possible prognostic significance
Authors: Buccoliero Anna Maria , Caldarella Adele , Arganini Luisa , Mennonna Pasquale , Gallina Pasquale , Taddei Antonio , Taddei Gian Luigi
Published: August 2004

Cyclooxygenase‐2 (COX‐2) is the inducible form of the enzyme involved in the first two steps of the prostaglandins and thromboxane synthesis. Up‐regulation of COX‐2 is demonstrated in tumors where it can modulate tumoral progression, metastasis, multidrug resistance and angiogenesis. Selective COX‐2 inhibitors are seen with growing interest in the tumors treatment. This present study reviews the COX‐2 expression in 32 primary oligodendrogliomas (24 WHO II; eight WHO III) and two glioblastomas with prominent oligodendroglial features (WHO IV). Immunohistochemical results were compared with survival in order to verify the COX‐2 prognostic significance. COX‐2 positivity was found in 44% tumors. Median survival of the patients with a COX‐2 positive lesion was 37 months; median survival of the patients with a COX‐2 negative lesion was 93 months (P = 0.010). Twenty‐nine percent WHO grade II tumors, 87% WHO grade III, 50% WHO grade IV resulted COX‐2 positive (P = 0.016). In patients affected by WHO grade II oligodendroglioma, median survival was 24 and 96 months, respectively, in COX‐2 positive and negative lesions (P = 0.012). In conclusion, even if further studies on different, homogeneous and larger series in vivo are certainly necessary, it is believed that COX‐2 could really have a prognostic value and can be considered as a possible therapeutic opportunity.
Expression of insulin‐like growth factors in remyelination following ethidium bromide‐induced demyelination in the mouse spinal cord
Authors: Fushimi Shigeko , Shirabe Teruo
Published: August 2004

Insulin‐like growth factors, IGF‐I and IGF‐II, play important roles in development and myelination in the CNS, but little is known about the response of IGF after demyelination. The present study investigated the expression of IGF and their cognitive receptors in the process of remyelination following ethidium bromide (EBr)‐induced demyelination in the adult mouse spinal cord. The present results, in a quantitative real‐time PCR, showed significant increases in the levels of the mRNA for both IGF‐I and IGF‐II during both the demyelination and remyelination stages. The levels of IGF‐I receptor (IGF‐IR) mRNA increased from 10 days to 4 weeks after the EBr injection. The levels of IGF‐II receptor (IGF‐IIR) mRNA decreased for 6 days and then increased 10 days after the EBr injection. In situ hybridization studies showed the cells expressing IGF‐I mRNA to be mainly macrophage‐like cells, while those expressing IGF‐II mRNA were predominantly Schwann cell‐like cells invading the demyelinating lesion. The immunoreactivity for the IGF‐IR and IGF‐IIR increased in various kinds of cells within and around the demyelinating lesions from 6 days to 4 weeks after the EBr injection. These results suggest that locally produced IGF could partly be involved in some mechanisms underlying remyelination processes following the EBr‐induced demyelination in the mouse spinal cord.
Rationale of frequency of use of ciclopirox 1% shampoo in the treatment of seborrheic dermatitis: Results of a double‐blind, placebo‐controlled study comparing the efficacy of once, twice, and three times weekly usage
Authors: Abeck Dietrich ,   on behalf of the Loprox Shampoo Dosing Study Group
Published: August 2004

Background  Seborrheic dermatitis is a common inflammatory skin disorder. Although the precise etiology of seborrheic dermatitis is uncertain, yeasts of the genus Malassezia have been implicated. Ciclopirox is a broad‐spectrum, hydroxypyridone‐derived, synthetic antifungal agent with anti‐inflammatory properties.

Methods  A total of 183 patients were enrolled in this randomized, parallel‐group, double‐blind, vehicle‐controlled trial designed to compare three different application frequencies of ciclopirox 1% shampoo: once, twice, and three times weekly. The main efficacy parameters were based on 6‐point ordinal scales describing the disease's signs and symptoms (scaling, inflammation and itching), global status of seborrheic dermatitis, and global change of seborrheic dermatitis.

Results  Each application frequency of ciclopirox 1% shampoo was found to significantly improve the signs and symptoms of seborrheic dermatitis of the scalp after 4 weeks of treatment. Furthermore, the therapeutic index calculated from the global change in seborrheic dermatitis score increased with increasing application frequency; therapeutic index scores increased from vehicle (1.25) to ciclopirox 1% once (3.30), twice (3.50), and three times (3.56) weekly. No serious adverse events were recorded during the course of the study.

Conclusions  Ciclopirox 1% shampoo, applied once, twice or three times weekly, is a safe and acceptable preparation that improves seborrheic dermatitis of the scalp, suggesting that this is an alternative treatment for this indication.
Safety and efficacy of ciclopirox 1% shampoo for the treatment of seborrheic dermatitis of the scalp in the US population: Results of a double‐blind, vehicle‐controlled trial
Authors: Lebwohl Mark , Plott Todd
Published: August 2004

Background  Seborrheic dermatitis is a common inflammatory skin disorder. Yeasts of the genus Malassezia have been implicated in the etiology of seborrheic dermatitis, although this connection remains controversial. Ciclopirox is a synthetic, hydroxypyridone‐derived, broad‐spectrum antifungal agent with anti‐inflammatory properties.

Methods  A total of 499 US patients with seborrheic dermatitis of the scalp were randomized to apply either ciclopirox shampoo 1% or vehicle twice weekly for 4 weeks. The main efficacy parameters were based on 6‐point ordinal scales describing the disease's signs and symptoms (scaling, erythema and itching) and a 6‐point scale providing a global evaluation of the status of seborrheic dermatitis.

Results  Ciclopirox was significantly better than vehicle in effectively treating seborrheic dermatitis. ‘Effective treatment’ (score of 0 or 1 for disease status, scaling and erythema) was achieved in 26.0% of ciclopirox‐treated patients compared with 12.9% of vehicle‐treated patients (P = 0.0001; OR: 2.383, 95% CI: 1.494–3.799). The majority of subjects experienced adverse events that were mild in intensity, with skin and appendage reactions the most commonly reported, at similar frequency in both groups.

Conclusions  Ciclopirox shampoo 1% is effective and safe in the treatment of seborrheic dermatitis of the scalp.
Nicorandil associated anal ulceration
Authors: Watson A. , Suttie S. , Fraser A. , O'Kelly T. , Loudon M.
Published: August 2004

Objective  Nicorandil is a vasodilator used to control angina. It has been associated with oral and anal ulceration that resolves upon withdrawal of the drug.

Patients and methods  We report a series of 13 patients with nonspecific anal ulceration all of whom were receiving nicorandil for control of symptoms of ischaemic heart disease.

Results  All the ulcers had similar clinical and histological appearances. All the ulcers healed on withdrawal of the drug.

Conclusion  Nicorandil‐associated anal ulceration shouldbe considered in the differential diagnoses of nonhealing anal ulcers.