Murine, but not human, ephrin-B2 can be efficiently cleaved by the serine protease kallikrein-4: implications for xenograft models of human prostate cancer.

BACKGROUND: Ephrin-B2 is the sole physiologically-relevant ligand of the receptor tyrosine kinase EphB4, which is over-expressed in many epithelial cancers, including 66% of prostate cancers, and contributes to cancer cell survival, invasion and migration. Crucially, however, the cancer-promoting EphB4 signalling pathways are independent of interaction with its ligand ephrin-B2, as activation of ligand-dependent signalling causes tumour suppression. Ephrin-B2, however, is often found on the surface of endothelial cells of the tumour vasculature, where it can regulate angiogenesis to support tumour growth. Proteolytic cleavage of endothelial cell ephrin-B2 has previously been suggested as one mechanism whereby the interaction between tumour cell-expressed EphB4 and endothelial cell ephrin-B2 is regulated to support both cancer promotion and angiogenesis. METHODS: An in silico approach was used to search accessible surfaces of 3D protein models for cleavage sites for the key prostate cancer serine protease, KLK4, and this identified murine ephrin-B2 as a potential KLK4 substrate. Mouse ephrin-B2 was then confirmed as a KLK4 substrate by in vitro incubation of recombinant mouse ephrin-B2 with active recombinant human KLK4. Cleavage products were visualised by SDS-PAGE, silver staining and Western blot and confirmed by N-terminal sequencing. RESULTS: At low molar ratios, KLK4 cleaved murine ephrin-B2 but other prostate-specific KLK family members (KLK2 and KLK3/PSA) were less efficient, suggesting cleavage was KLK4-selective. The primary KLK4 cleavage site in murine ephrin-B2 was verified and shown to correspond to one of the in silico predicted sites between extracellular domain residues arginine 178 and asparagine 179. Surprisingly, the highly homologous human ephrin-B2 was poorly cleaved by KLK4 at these low molar ratios, likely due to the 3 amino acid differences at this primary cleavage site. CONCLUSION: These data suggest that in in vivo mouse xenograft models, endogenous mouse ephrin-B2, but not human tumour ephrin-B2, may be a downstream target of cancer cell secreted human KLK4. This is a critical consideration when interpreting data from murine explants of human EphB4+/KLK4+ cancer cells, such as prostate cancer cells, where differential effects may be seen in mouse models as opposed to human clinical situations.

Differential Phosphorylation of Akt and signaling in CD4+ T Cells in Pathogenic and Apathogenic SIV Infection.

Increased CD4+ T cell apoptosis and activation induced cell death (AICD) as a result of HIV infection in humans and SIV infection in Rhesus macaques (RM) is indicative of disease. Some non-human primate species naturally infected by SIV, such as African sooty mangabeys (SM), do not succumb to SIV despite high viral loads. Previously, we showed that mRNA levels of GSK-3ß a kinase involved in T cell signaling, are significantly decreased in SIV+ RM compared to SIV+ SM. The current study confirms that expression of GSK-3ß is decreased at the protein level in SIV+ RM. In addition, CD4+ T cells from SIV+ RM, but not other animals show an increase in both total Akt, a kinase directly interacting with GSK-3ß and p-AktThr308 in response to stimulation via CD3/CD28, which is associated with an increase in apoptosis. Furthermore, the differences between the uninfected and pathogenically or non-pathogenically infected animals are not only species specific, but also T cell subset specific and that these trends correlate with AICD. This is one of few studies indicating the activity of Akt can be specific to only one phosphorylation site and may be linked to the differences in AICD and resistance to the lentivirus induced disease.

Inhibiting Eph kinase activity may not be "Eph"ective for cancer treatment.

Several Eph receptor tyrosine kinases (RTKs) are commonly over-expressed in epithelial and mesenchymal cancers and are recognized as promising therapeutic targets. Although normal interaction between Eph receptors and their ephrin ligands stimulates kinase activity and is generally tumor suppressive, significant Eph over-expression allows activation of ligand- and/or kinase-independent signaling pathways that promote oncogenesis. Single-agent kinase inhibitors are widely used to target RTK-driven tumors but acquired and de novo resistance to such agents is a major limitation to effective clinical use. Accumulating evidence suggests that Ephs can be inhibited by "leaky" or low-specificity kinase inhibitors targeted at other RTKs. Such off-target effects may therefore inadvertently promote ligand- and/or kinase-independent oncogenic Eph signaling, thereby providing a new mechanism by which resistance to the RTK inhibitors can emerge. We propose that combining specific, non-leaky kinase inhibitors with tumor-suppressive stimulators of Eph signaling may provide more effective treatment options for overcoming treatment-induced resistance and clinical failure.

The exercise intensity-music-tempo preference relationship: A decennial revisit.

Tempo is a key determinant of the motivational effects of music during exercise and has been the focus of numerous empirical studies (e.g., Karageorghis & Jones, 2014). The present study sought to address the limitations of previous related work and revisit the relationship between exercise intensity and music-tempo preference using unfamiliar, non-lyrical music (to isolate the tempo manipulation). A within-within experimental design was employed to test hypotheses pertaining to the non-linear relationship and associated psychological outcomes (e.g., core affect and state attention). Twenty-four participants (Mage = 20.6 years, SD = 0.92 years) exercised at five intensities (10% of peak V̇O2 below ventilatory threshold [VT]; 5% of peak V̇O2 below VT, at VT, midway between VT and the respiratory compensation point [RCP], and at RCP) during which they were administered music tracks at four tempi (90 bpm, 110 bpm, 130 bpm and 150 bpm) and a no-music control. A music liking item, measures of core affect (valence and arousal), attentional focus and perceived exertion were recorded during the exercise bouts. Results indicated that unlike previous findings with familiar, lyrical music, there was no discernible relationship between exercise intensity and preference for music tempo. The most positive psychological outcomes were associated with fast-tempo music. In accord with previous findings, slow-tempo music attracted low liking scores and the least desirable psychological outcomes at every exercise intensity. The present findings have implications for the use of unfamiliar, non-lyrical music during exercise. Specifically, that such music should be ∼10 bpm faster than familiar, lyrical music.

Test-retest reliability of the BOLD pharmacological MRI response to ketamine in healthy volunteers.

The pharmacological MRI (phMRI) technique is being increasingly used in both pre-clinical and clinical models to investigate pharmacological effects on task-free brain function. Ketamine, an N-methyl-d-aspartate receptor (NMDAR) antagonist, induces a strong phMRI response and represents a promising pharmacological model to investigate the role of glutamatergic abnormalities in psychiatric symptomatology. The aim of this study was to assess whether the brain response to ketamine is reliable in order to validate ketamine phMRI as a mechanistic marker of glutamatergic dysfunction and to determine its utility in repeated measures designs to detect the modulatory effect of other drugs. Thus we assessed the test-retest reliability of the brain response to ketamine in healthy volunteers and identified an optimal modelling approach with reliability as our selection criterion. PhMRI data were collected from 10 healthy male participants, at rest, on two separate occasions. Subanaesthetic doses of I.V. ketamine infusion (target plasma levels 50 ng/mL and 75 ng/mL) were administered in both sessions. Test-retest reliability of the ketamine phMRI response was assessed voxel-wise and on pre-defined ROIs for a range of temporal design matrices including different combinations of nuisance regressors designed to model shape variance, linear drift and head motion. Effect sizes are also reported. All models showed a significant and widespread response to low-dose ketamine in predicted cerebral networks and as expected, increasing the number of model parameters improved model fit. Reliability of the predefined ROIs differed between the different models assessed. Using reliability as the selection criterion, a model capturing subject motion and linear drift performed the best across two sessions. The anatomical distribution of effects for all models was consistent with results of previous imaging studies in humans with BOLD signal increases in regions including midline cingulate and supracingulate cortex, thalamus, insula, anterior temporal lobe and ventrolateral prefrontal structures, and BOLD signal decreases in the subgenual cingulate cortex. This study represents the first investigation of the test-retest reliability of the BOLD phMRI response to acute ketamine challenge. All models tested were effective at describing the ketamine response although the design matrix associated with the highest reliability may represent a robust and well-characterised ketamine phMRI assay more suitable for repeated-measures designs. This ketamine assay is applicable as a model of neurotransmitter dysfunction suitable as a pharmacodynamic imaging tool to test and validate modulatory interventions, as a model of NMDA hypofunction in psychiatric disorders, and may be adapted to understand potential antidepressant and analgesic effects of NMDAR antagonists.

Variation in fecal egg counts in horses managed for conservation purposes: individual egg shedding consistency, age effects and seasonal variation.

Cyathostomins are the most prevalent equine intestinal parasites and resistance has been reported in these nematodes against all 3 licensed anthelmintic classes. Strategies need to be developed that are less dependent upon drugs and more reliant on management-based control. To develop these we need to understand natural transmission patterns better. Here, we analysed longitudinal fecal egg count (FEC) data from 5 pony populations used for conservation purposes. We tested how egg excretion varied amongst populations and individuals, and how this was affected by age and climate. There was evidence for consistency in FECs over time at the individual level; this was generally weak and accounted for <10% of the total variance. Animals <5 years old had higher FECs and there was profound seasonal variation in FECs, with highest levels recorded in spring/summer. Effects of monthly temperature and rainfall explained most, but not all, of the observed seasonal variation and associations between climate measures and FECs were stronger in younger versus adult animals. One population was occasionally treated with anthelmintics and analysis of this population suggested that treatment substantially altered the seasonal dynamics. This paper highlights the variability in strongyle egg excretion amongst individuals and the factors involved in this variation.

Unresolved question of the 10He ground state resonance.

The ground state of (10)He was populated using a 2p2n-removal reaction from a 59 MeV/u (14)Be beam. The decay energy of the three-body system, (8)He+n+n, was measured and a resonance was observed at E=1.60(25) MeV with a 1.8(4) MeV width. This result is in agreement with previous invariant mass spectroscopy measurements, using the (11)Li(-p) reaction, but is inconsistent with recent transfer reaction results. The proposed explanation that the difference, about 500 keV, is due to the effect of the extended halo nature of (11)Li in the one-proton knockout reaction is no longer valid as the present work demonstrates that the discrepancy between the transfer reaction results persists despite using a very different reaction mechanism, (14)Be(-2p2n).

Multicentre survey of radiologically inserted gastrostomy feeding tube (RIG) in the UK.

AIMS: To evaluate the variance in current UK clinical practice and clinical outcomes for direct percutaneous radiologically inserted gastrostomy (RIG). MATERIALS AND METHODS: A prospective UK multicentre survey of RIG performed between October 2008 and August 2010 was performed through the British Society of Gastrointestinal and Abdominal Radiology (BSGAR). RESULTS: Data from 684 patients were provided by 45 radiologists working at 17 UK centres. Two hundred and sixty-three cases (40%) were performed with loop-retained catheters, and 346 (53%) with balloon-retained devices. Sixty percent of all patients experienced pain in the first 24 h, but settled in the majority thereafter. Early complications, defined as occurring in the first 24 h, included minor bleeding (1%), wound infection (3%), peritonism (2%), and tube misplacement (1%). Late complications, defined as occurring between day 2 and day 30 post-procedure, included mild pain (30%), persisting peritonism (2%), and 30 day mortality of 1% (5/665). Pre-procedural antibiotics or anti-methicillin-resistant Staphylococcus aureus (MRSA) prophylaxis did not affect the rate of wound infection, peritonitis, post-procedural pain, or mortality. Ninety-three percent of cases were performed using gastropexy. Gastropexy decreased post-procedural pain (p < 0.001), but gastropexy-related complications occurred in 5% of patients. However, post-procedure pain increased with the number of gastropexy sutures used (p < 0.001). The use of gastropexy did not affect the overall complication rate or mortality. Post-procedure pain increased significantly as tube size increased (p < 0.001). The use of balloon-retention feeding tubes was associated with more pain than the deployment of loop-retention devices (p < 0.001). CONCLUSION: RIG is a relatively safe procedure with a mortality of 1%, with or without gastropexy. Pain is the commonest complication. The use of gastropexy, fixation dressing or skin sutures, smaller tube sizes, and loop-retention catheters significantly reduced the incidence of pain. There was a gastropexy-related complication rate in 5% of patients. Neither pre-procedural antibiotics nor anti-MRSA prophylaxis affected the rate of wound infection.

Global influence of mantle temperature and plate thickness on intraplate volcanism.

The thermochemical structure of lithospheric and asthenospheric mantle exert primary controls on surface topography and volcanic activity. Volcanic rock compositions and mantle seismic velocities provide indirect observations of this structure. Here, we compile and analyze a global database of the distribution and composition of Neogene-Quaternary intraplate volcanic rocks. By integrating this database with seismic tomographic models, we show that intraplate volcanism is concentrated in regions characterized by slow upper mantle shear-wave velocities and by thin lithosphere (i.e. <100 km). We observe a negative correlation between shear-wave velocities at depths of 125-175 km and melt fractions inferred from volcanic rock compositions. Furthermore, mantle temperature and lithospheric thickness estimates obtained by geochemical modeling broadly agree with values determined from tomographic models that have been converted into temperature. Intraplate volcanism often occurs in regions where uplifted (but undeformed) marine sedimentary rocks are exposed. Regional elevation of these rocks can be generated by a combination of hotter asthenosphere and lithospheric thinning. Therefore, the distribution and composition of intraplate volcanic rocks through geologic time will help to probe past mantle conditions and surface processes.

The emergence of qnr-mediated quinolone resistance among Enterobacteriaceae in Jamaica.

OBJECTIVE: Quinolone resistance is usually caused by various chromosomal mutations, but has been more recently associated with plasmids which carry the qnr determinant. The aim of this study is to investigate the prevalence of qnr genes in clinical isolates of Enterobacteriaceae in Jamaica. METHODS: A total of 255 non-duplicate fluoroquinolone-resistant Enterobacteriaceae clinical isolates, comprising 232 Escherichia coli, 20 Klebsiella species and three Enterobacter spp were collected between October 2007 and November 2008 from hospitalized patients in Jamaica. The presence of the qnr gene was screened by PCR using specific primers for qnrA, qnrB and qnrS in extracted plasmid DNA. RESULTS: Eighty-three (32.5%) of these isolates were qnr-positive, of which 47.0% housed the qnrA gene only, 1.2% qnrB and 9.6% qnrS only. Another 36.1% possessed both qnrA and qnrS genes. Approximately 30% of the quinolone-resistant E coli isolates harboured the qnr gene while 50% Klebsiella spp and all Enterobacter spp were positive. CONCLUSION: The emergence of qnr-mediated quinolone resistance among clinical Enterobacteriaceae isolates is described for the first time in Jamaica.

Entoloma sequestratum, a new species from northern Thailand, and a worldwide key to sequestrate taxa of Entoloma (Entolomataceae).

Based on our study of the morphology and genetics of sporocarps collected in the mountains of northern Thailand, we herein describe Entoloma sequestratum as a new sequestrate member of the Entolomotaceae. This serves as the first report of a sequestrate member of the genus from Thailand. In addition, we provide a worldwide key to all of the described sequestrate members of the genus.

Description and life cycle of a new Didymium (Myxomycetes) from arid areas of Argentina and Chile.

A new species of Didymium (Myxomycetes), D. infundibuliforme, is described herein, and details are provided on its life cycle as observed in spore to spore culture on agar. The new species was recorded during intensive studies of areas of the Monte Desert in Argentina and the Atacama Desert in Chile. It has been collected directly in the field in both countries on several occasions over 4 y and isolated in moist chamber cultures prepared with material from native plant species. The characters that make this species unique in the genus are its funnel-shape sporocarps with white stalks, the apical circumscissile dehiscence of the sporotheca that causes the base to resemble a calyculus and the ornamentation on the spores. The morphology of specimens of this new myxomycete was examined with scanning electron microscopy and light microscopy, and micrographs of relevant details are included in this paper.

Correct and incorrect use of child restraints: results from an urban survey in New Zealand.

This study describes the incorrect use of child restraints among car drivers with young children and examines factors that may influence their misuse. A cross-sectional survey was undertaken in supermarket car parks with car drivers travelling with children under the age of 8 years. The main measure was errors in child restraint use. Short interviews were conducted with 1113 drivers with a close inspection of the child restraints used in the vehicles. Only 4% of children were unrestrained but 64% of drivers made at least one error in restraint use. Most respondents thought using a restraint was easy, but 65% of these drivers made at least one error. Child restraints are used, but many are incorrectly fitted and/or have the child incorrectly placed in them. Correct use is a moderately complex task. Restraint systems need to be designed to minimize the opportunity for error and maximize safety.

Carbohydrate metabolism and capillary basement-membrane thickness in children. I. cross-sectional studies.

Thirty-nine children from three to 16 years of age were included in this study. Nineteen were diabetics, seven were "suspected" diabetics (with evidence of glucose intolerance but without repeated fasting hyperglycemia), and 13 were controls. Mean glucose disappearance rates (K) during intravenous glucose tolerance tests (IVGTTs) were 2.19 for the controls, 1.23 for the suspected diabetics, and 0.70 for 14 diabetics tested; the differences were statistically significant. Diabetics had the smallest and suspected diabetics the greatest plasma insulin responses during IVGTTs. Fasting plasma growth hormone (GH) varied widely. GH generally decreased or remained unchanged during IVGTTs, but two diabetics exhibited slight increases and two sustpected diabetics pronounced increases. Basement-membrane thickness (BMT) was examined in 42 quadriceps femoris needle biopsies. Average BMT (ABMT) and minimum BMT (MBMT) correlated well (r = 0.91). BMT did not correlate well with age or, in the diabetics, with duration of clinical disease. Diabetics had the greatest and controls the least mean ABMT and MBMT, but the differences were not statistically significant. High values (those exceeding mean control values by more than two standard deviations) were much more common among the suspected diabetics and the diabetics. One of 13 controls, three of six suspected diabetics, and six of 19 diabetics had high ABMT values; two suspected diabetics and five diabetics had high MBMT values. Correlations between BMT and K were negative for the most part, but correlation coefficients were small. Serial studies in four of the children suggest that BMT and glucose tolerance tend to change in opposite directions.

Lung cancer screening with low-dose spiral computed tomography.

Computed tomography (CT) has been compared to plain radiographs and bronchial washings as a screening tool for lung cancer. In comparison with other screening modalities, CT allows detection of lung lesions at an earlier cancer stage. Technologic improvements have decreased imaging costs, thus making chest CT a more feasible option as a screening tool in the community hospital. In this study, smokers over the age of 45 years with a greater than 20 pack-year smoking history were referred for screening chest CT. Noncalcified nodules larger than 10 mm underwent CT-guided biopsy, and smaller nodules underwent follow-up CT in 3 months. Currently, patients have been followed for 4 years. The prevalence, stage, and histology of lung cancer were compared to study results from academic centers. Eighty-seven patients underwent screening chest CT. The study population was 51 per cent male with a mean age of 64 +/- 9 years. Four (3 female and 1 male) patients were biopsied and found to have lung cancer giving a prevalence of 5 per cent. Stage IA disease was found in three patients and stage IIIA disease was found in one patient. Adenocarcinoma was present in two patients, adeno-squamous carcinoma in one patient, and squamous cell carcinoma in one patient. The stage and histology of lung carcinomas in this study were comparable to studies performed at larger institutions. However, the disease prevalence was almost double the highest prevalence found in other studies. This discrepancy could be related to study size, as the patient populations were similar. Clearly, screening chest CT in the community setting is equally efficacious in the diagnosis of lung cancer at earlier stages. Following these patients beyond the 5-year mark will give some insight on the effect of screening chest CT on the mortality of lung cancer.

A history of total mercury in edible muscle of fish from lakes in northern Canada.

Subsistence fishing has been an important source of food for Native People in northern Canada since prehistoric time. Measurements of the levels of mercury in edible muscle of northern fish have been undertaken for over three decades in efforts to evaluate the risks of consuming northern fish. This report summarizes the data obtained from 7974 fish of 25 species from sites distributed from the Yukon to Labrador. The most abundant species were lake trout, lake whitefish, arctic char, walleye, northern pike and burbot. The question being asked was essentially "Are the fish safe to eat?" The results were used to support decisions on fishing and consumption of fish. They were sorted in several ways, into concentration ranges corresponding to human consumption guidelines, into political jurisdictions and into types of bedrock geology. Overall walleye, northern pike and lake trout, usually exceeded the subsistence consumption guideline of 0.2 microg g-1 total mercury and often exceeded the higher guideline of 0.5 microg g-1 total mercury for commercial sales of fish. Mercury in burbot, another facultative predator, was often lower but several still exceeding a guideline. Arctic char collections were mostly from anadromous populations and these had very low levels of mercury, presumably reflecting marine food sources. Lake whitefish were among the cleanest fish examined with 69 of 81 collections falling in the lowest range. Most collections were from sites in sedimentary rock. However a few sites were in metamorphic, intrusive or volcanic rocks and these, taken together, tended to have a higher proportion of sites in the higher ranges of mercury. These results indicate a widespread problem with mercury in subsistence fisheries for predator species of fish with the problem being most problematic for Nunavut.

Direct nn-Scattering Measurement With the Pulsed Reactor YAGUAR.

Although crucial for resolving the issue of charge symmetry in the nuclear force, direct measurement of nn-scattering by colliding free neutrons has never been performed. At present the Russian pulsed reactor YAGUAR is the best neutron source for performing such a measurement. It has a through channel where the neutron moderator is installed. The neutrons are counted by a neutron detector located 12 m from the reactor. In preliminary experiments an instantaneous value of 1.1 × 10(18)/cm(2)s was obtained for the thermal neutron flux density. The experiment will be performed by the DIANNA Collaboration as International Science & Technology Center (ISTC) project No. 2286.

Effects of high-dose oral acyclovir on herpesvirus disease and survival in patients with advanced HIV disease: a double-blind, placebo-controlled study. European-Australian Acyclovir Study Group.

OBJECTIVE: To determine the efficacy of high-dose oral acyclovir in preventing cytomegalovirus (CMV) and other herpesvirus disease in patients with advanced HIV disease and to evaluate its effect on patient survival. DESIGN: Double-blind, placebo-controlled randomized trial of up to 1 year's therapy. SETTING: Outpatient clinics in 16 hospitals in Europe and Australia. PARTICIPANTS: A total of 302 patients with Centers for Disease Control and Prevention stage IV HIV disease, seropositive for CMV and with CD4+ lymphocyte counts < or = 150 x 10(6)/l. INTERVENTIONS: Oral acyclovir (800 mg, four times daily) or matching placebo for 48 weeks. MAIN OUTCOME MEASURES: Time to development of CMV and other herpesvirus disease. Following the results of another study, the protocol was amended to make survival a second major endpoint. RESULTS: Acyclovir failed to reduce the incidence of CMV disease: the probability of developing CMV disease at 1 year was 0.24 and 0.23 in the placebo and acyclovir groups, respectively (P = 0.53). However, acyclovir significantly reduced the probability of dying at 1 year of follow-up (from 0.39 to 0.23; P = 0.018). As expected, acyclovir significantly reduced the incidence and frequency of herpes simplex virus disease. There were no notable differences between treatment groups in clinically adverse experiences and no changes in haematological parameters to indicate clinically significant drug-induced toxicity. CONCLUSIONS: High-dose acyclovir failed to reduce the incidence of CMV disease, but significantly reduced the probability of dying at 1 year of follow-up.

CgDN3: an essential pathogenicity gene of colletotrichum gloeosporioides necessary to avert a hypersensitive-like response in the host Stylosanthes guianensis.

A gene of Colletotrichum gloeosporioides that is induced by nitrogen starvation in axenic culture and is expressed at the early stages of infection of the host Stylosanthes guianensis has been identified and its role in pathogenicity tested. The sequence of this gene, named CgDN3, indicated that it encodes a protein of 74 amino acids that contains a predicted 18 amino acid signal sequence for secretion of a basic 54 amino acid mature protein with weak homology to an internal region of plant wall-associated receptor kinases. Mutants of C. gloeosporioides were produced by homologous recombination in which part of the coding sequence and promoter region of the CgDN3 gene was replaced with a hygromycin-resistance gene cassette. Mutations in the CgDN3 gene were confirmed in two independent transformants and Northern (RNA) analysis demonstrated the disrupted CgDN3 gene was not expressed. The mutants had faster mycelial growth rates in vitro but produced spores that germinated to form appressoria normally on the leaf surface. However, the CgDN3 mutants were unable to infect and reproduce on intact host leaves. Microscopic analysis revealed small clusters of necrotic host cells at inoculation sites on leaves, suggesting that these mutants elicited a localized, host hypersensitive-like response. The mutants were able to grow necrotrophically and reproduce on leaves when conidia were inoculated directly onto wound sites. The putative promoter region of the CgDN3 gene was fused to a gene encoding a modified jellyfish green fluorescent protein and introduced into the fungus. Following inoculation, strong expression of green fluorescent protein was observed in primary infection vesicles in infected epidermal cells with weaker expression evident in hyphae growing within infected leaf tissue. These findings indicate that CgDN3 encodes a novel pathogenicity determinant associated with the biotrophic phase of primary infection and required to avert a hypersensitive-like response by a compatible host.