Maize kernel metabolome involved in resistance to fusarium ear rot and fumonisin contamination

Fusarium verticillioides poses a threat to worldwide maize production due to its ability to infect maize kernel and synthesize fumonisins that can be accumulated above safety levels for humans and animals. Maize breeding has been proposed as key tool to decrease kernel contamination with fumonisins, but metabolic studies complementary to genomic approaches are necessary to disclose the complexity of maize resistance. An untargeted metabolomic study was proposed using inbreds genetically related but with contrasting levels of resistance in order to uncover pathways implicated in resistance to Fusarium ear rot (FER) and fumonisin contamination in the maize kernel and to look for possible biomarkers. Metabolite determinations were performed in kernels collected at 3 and 10 days after inoculation with F. verticillioides (dat). Discriminant metabolites between resistant and susceptible RILs were rather found at 10 than 3 dat, although metabolite differences at later stages of colonization could be driven by subtle variations at earlier stages of infection. Within this context, differences for membrane lipid homeostasis, methionine metabolism, and indolacetic acid conjugation seemed highly relevant to distinguish between resistant and susceptible inbreds, confirming the polygenic nature of resistance to FER and fumonisin contamination in the maize kernels. Nevertheless, some specific metabolites such as the polyamine spermidine and/or the alkaloid isoquinoline seemed to be promising indirect selection traits to improve resistance to FER and reduce fumonisin accumulation. Therefore, in vitro and in vivo experiments will be necessary to validate the inhibitory effects of these compounds on fumonisins biosynthesis.

Genomic versus phenotypic selection to improve corn borer resistance and grain yield in maize

Introduction

The study of yield and resistance/tolerance to pest are related traits fundamental for maize breeding programs. Genomic selection (GS), which uses all marker information to calculate genomic breeding values, is presented as an emerging alternative to phenotypic and marker-assisted selections for improving complex traits controlled by many genes with small effects. Therefore, although phenotypic selection (PS) has been effective for increasing resistance and yield under high infestation with maize stem borers, higher genetic gains are expected to be obtained through GS based on the complex architecture of both traits. Our objective was to test whether GS is more effective than PS for improving resistance and/or tolerance to maize stem borers and grain yield.

Methods

For this, we compared different selection programs based on phenotype and genotypic value for a single trait, resistance or yield, and for both traits together.

Results and discussion

We obtained that GS achieved the highest genetic gain for yield, meanwhile phenotypic selection for yield was the program that achieved the highest reduction of tunnel length, but was ineffective for increasing yield. However, phenotypic or genomic selection for increased resistance may be more effective in improving both traits together; although the gains per cycle would be small for both traits.

Inbred Selection for Increased Resistance to Kernel Contamination with Fumonisins

In temperate world-wide regions, maize kernels are often infected with the fumonisin-producing fungus Fusarium verticillioides which poses food and feed threats to animals and humans. As maize breeding has been revealed as one of the main tools with which to reduce kernel contamination with fumonisins, a pedigree selection program for increased resistance to Fusarium ear rot (FER), a trait highly correlated with kernel fumonisin content, was initiated in 2014 with the aim of obtaining inbred lines (named EPFUM) with resistance to kernel contamination with fumonisins and adapted to our environmental conditions. The new released EPFUM inbreds, their parental inbreds, hybrids involving crosses of one or two EPFUM inbreds, as well as commercial hybrids were evaluated in the current study. The objectives were (i) to assess if inbreds released by that breeding program were significantly more resistant than their parental inbreds and (ii) to examine if hybrids derived from EPFUM inbreds could be competitive based on grain yield and resistance to FER and fumonisin contamination. Second-cycle inbreds obtained through this pedigree selection program did not significantly improve the levels of resistance to fumonisin contamination of their parental inbreds; however, most EPFUM hybrids showed significantly better resistance to FER and fumonisin contamination than commercial hybrids did. Although European flint materials seem to be the most promising reservoirs of alleles with favorable additive and/or dominance effects for resistance to kernel contamination with fumonisins, marketable new Reid × Lancaster hybrids have been detected as they combine high resistance and yields comparable to those exhibited by commercial hybrids. Moreover, the white kernel hybrid EPFUM-4 × EP116 exploits the genetic variability within the European flint germplasm and can be an alternative to dent hybrid cultivation because white flint grain can lead to higher market prices.

Genomics and Pathways Involved in Maize Resistance to Fusarium Ear Rot and Kernel Contamination With Fumonisins

Fusarium verticillioides is a causal agent of maize ear rot and produces fumonisins, which are mycotoxins that are toxic to animals and humans. In this study, quantitative trait loci (QTLs) and bulk-segregant RNA-seq approaches were used to uncover genomic regions and pathways involved in resistance to Fusarium ear rot (FER) and to fumonisin accumulation in maize kernels. Genomic regions at bins 4.07-4.1, 6-6.01, 6.04-6.05, and 8.05-8.08 were related to FER resistance and/or reduced fumonisin levels in kernels. A comparison of transcriptomes between resistant and susceptible inbred bulks 10 days after inoculation with F. verticillioides revealed 364 differentially expressed genes (DEGs). In the resistant inbred bulks, genes involved in sink metabolic processes such as fatty acid and starch biosynthesis were downregulated, as well as those involved in phytosulfokine signaling and many other genes involved in cell division; while genes involved in secondary metabolism and compounds/processes related to resistance were upregulated, especially those related to cell wall biosynthesis/rearrangement and flavonoid biosynthesis. These trends are indicative of a growth-defense trade-off. Among the DEGs, Zm00001d053603, Zm00001d035562, Zm00001d037810, Zm00001d037921, and Zm00001d010840 were polymorphic between resistant and susceptible bulks, were located in the confidence intervals of detected QTLs, and showed large differences in transcript levels between the resistant and susceptible bulks. Thus, they were identified as candidate genes involved in resistance to FER and/or reduced fumonisin accumulation.

Genomics of maize resistance to kernel contamination with fumonisins using a multiparental advanced generation InterCross maize population (MAGIC)

Maize kernel is exposed to several fungal species, most notably Fusarium verticillioides, which can contaminate maize kernels with fumonisins. In an effort to increase genetic gains and avoid the laborious tasks of conventional breeding, the use of marker-assisted selection or genomic selection programs was proposed. To this end, in the present study a Genome Wide Association Study (GWAS) was performed on 339 RILs of a Multiparental Advanced Generation InterCross (MAGIC) population that had previously been used to locate Quantitative Trait Locus (QTL) for resistance to Fusarium Ear Rot (FER). Six QTLs for fumonisin content were detected in the bins 3.08, 4.07, 4.10, 7.03-7.04, 9.04-9.05 and 10.04-10.5. Five of the six QTLs collocate in regions where QTLs for FER were also found. However, the genetic variation for fumonisin content in kernel is conditioned by many other QTLs of small effect that could show QTL x environment interaction effects. Although a genomic selection approach to directly reduce fumonisin content in the kernel could be suitable, improving resistance to fumonisin content by genomic selection for FER would be more advisable.

Maize Resistance to Stem Borers Can Be Modulated by Systemic Maize Responses to Long-Term Stem Tunneling

Limited attention has been paid to maize (Zea mays L.) resistance induced by corn borer damage, although evidence shows that induced defenses have lower resource allocation costs than constitutive defenses. Maize responses to short- and long-term feeding by the Mediterranean corn borer (MCB, Sesamia nionagrioides) have been previously studied, but the suggested differences between responses could be due to experimental differences. Therefore, in the current study, a direct comparison between short- and long-term responses has been made. The objectives were (i) to determine changes in the level of antibiosis of the stems induced by feeding of S. nonagrioides larvae for 2days (short-term feeding) and 9days (long-term feeding), (ii) to characterize the metabolome of the stems' short- and long-term responses to borer feeding, and (iii) to look for metabolic pathways that could modulate plant resistance to MCB. Defenses were progressively induced in the resistant inbred, and constitutive defenses were broken down in the susceptible inbred. Results suggest that the different resistance levels of the two inbreds to stem tunneling by MCB could depend on their ability to establish a systemic response. Based on these results, a high throughput look for specific metabolites implicated in systemic induced resistance to maize stem borers is recommended; the current focus on constitutive defense metabolites has not been successful in finding molecules that would be valuable tools for pest control.

Alarmin-activated B cells accelerate atherosclerosis after myocardial infarction via plasma cell-immunoglobulin dependent mechanisms

Introduction

Myocardial infarction (MI) accelerates atherosclerosis and for years greatly increases the risk of recurrent cardiovascular events, such as stroke and MI. B cell-derived autoantibodies produced in response to MI also persist for years.

Purpose

We investigated the role of B cells in adaptive immune responses to MI.

Methods

We used an apolipoprotein-E-deficient (ApoE−/−) mouse model of MI-accelerated atherosclerosis to assess the importance of B cells using loss and gain of function approaches. In loss of function experiment, after inducing an MI we depleted B cells using an anti-CD20 antibody. Gain of function experiments involve transfers of purified MI-B cells from different donor mice, isolated one week after MI, into atherosclerotic ApoE−/− mice.

Results

Depletion of B cells in MI mice prevented immunoglobulin G accumulation in plaques and MI-induced acceleration of atherosclerosis. Adoptive transfer of wildtype MI-B cells into atherosclerotic ApoE−/− mice greatly increased IgG accumulation in plaque and accelerated atherosclerosis in recipient mice. Cytokines that promote humoral immunity were also greatly increased in B cells activated by MI. These cells formed germinal centres within the spleen where they differentiated into antibody-producing plasma cells. Transfer of MI-B cells deficient in Blimp-1, the transcriptional repressor that drives their terminal differentiation to antibody-producing plasma cells failed to accelerate atherosclerosis in recipient mice. Alarmins released from infarcted heart were responsible for activation of B cells via toll-like receptors; transfer of MI-B cells deficient in MyD88, the canonical adaptor protein for inflammatory signaling downstream of toll-like receptors, prevented acceleration of atherosclerosis in recipient mice.

Conclusion

Our data implicate early B cell activation and autoantibodies as a central cause for accelerated atherosclerosis post MI and identifies novel therapeutic strategies towards preventing recurrent cardiovascular events such as MI and stroke.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): National Health and Medical Research Council of Australia

Genomics of Maize Resistance to Fusarium Ear Rot and Fumonisin Contamination

Food contamination with mycotoxins is a worldwide concern, because these toxins produced by several fungal species have detrimental effects on animal and/or human health. In maize, fumonisins are among the toxins with the highest threatening potential because they are mainly produced by Fusarium verticillioides, which is distributed worldwide. Plant breeding has emerged as an effective and environmentally safe method to reduce fumonisin levels in maize kernels, but although phenotypic selection has proved effective for improving resistance to fumonisin contamination, further resources should be mobilized to meet farmers' needs. Selection based on molecular markers linked to quantitative trait loci (QTL) for resistance to fumonisin contamination or/and genotype values obtained using prediction models with markers distributed across the whole genome could speed up breeding progress. Therefore, in the current paper, previously identified genomic regions, genes, and/or pathways implicated in resistance to fumonisin accumulation will be reviewed. Studies done until now have provide many markers to be used by breeders, but to get further insight on plant mechanisms to defend against fungal infection and to limit fumonisin contamination, the genes behind those QTLs should be identified.

Effect of Long-Term Feeding by Borers on the Antibiotic Properties of Corn Stems

Plant long-term response against chewing insects could become stronger than initial reactions and even turn into systemic. The objectives of the present study were 1) to evaluate whether the long-running attack to the stem by corn borers can improve the stem antibiotic properties; 2) to check whether hydroxycinnamic acids could be involved in this antibiotic response; 3) and to check whether elicitation by Sesamia nonagrioides Lef. (Lepidoptera: Noctuidae) regurgitant could activate long-term plant responses. In this sense, we observed that long-term feeding by S. nonagrioides larvae induced genotype-dependent changes in stem antibiosis and phenolic profiles, but the hydroxycinnamate content does not have a significant role in the systemic defense induced by the attack. In addition, response to long-term feeding by larvae could not be fully mimicked by elicitation using S. nonagrioides regurgitant alone. For the first time, it has been demonstrated that 'long-term' attack to the stem by corn borers can increase the stem antibiotic properties, and this has to be considered attending to breeding strategies.

QTLs for Resistance to Fusarium Ear Rot in a Multiparent Advanced Generation Intercross (MAGIC) Maize Population

Alternative approaches to linkage and association mapping using inbred panels may allow further insights into loci involved in resistance to Fusarium ear rot and lead to the discovery of suitable markers for breeding programs. Here, the suitability of a maize multiparent advanced-generation intercross population for detecting quantitative trait loci (QTLs) associated with Fusarium ear rot resistance was evaluated and found to be valuable in uncovering genomic regions containing resistance-associated loci in temperate materials. In total, 13 putative minor QTLs were located over all of the chromosomes, except chromosome 5, and frequencies of favorable alleles for resistance to Fusarium ear rot were, in general, high. These findings corroborated the quantitative characteristic of resistance to Fusarium ear rot in which many loci have small additive effects. Present and previous results indicate that crucial regions such as 210 to 220 Mb in chromosome 3 and 166 to 173 Mb in chromosome 7 (B73-RefGen-v2) contain QTLs for Fusarium ear rot resistance and fumonisin content.

Genome-wide association analysis for fumonisin content in maize kernels

BACKGROUND

Plant breeding has been proposed as one of the most effective and environmentally safe methods to control fungal infection and to reduce fumonisin accumulation. However, conventional breeding can be hampered by the complex genetic architecture of resistance to fumonisin accumulation and marker-assisted selection is proposed as an efficient alternative. In the current study, GWAS has been performed for the first time for detecting high-resolution QTL for resistance to fumonisin accumulation in maize kernels complementing published GWAS results for Fusarium ear rot.

RESULTS

Thirty-nine SNPs significantly associated with resistance to fumonisin accumulation in maize kernels were found and clustered into 17 QTL. Novel QTLs for fumonisin content would be at bins 3.02, 5.02, 7.05 and 8.07. Genes with annotated functions probably implicated in resistance to pathogens based on previous studies have been highlighted.

CONCLUSIONS

Breeding approaches to fix favorable functional variants for genes implicated in maize immune response signaling may be especially useful to reduce kernel contamination with fumonisins without significantly interfering in mycelia development and growth and, consequently, in the beneficial endophytic behavior of Fusarium verticillioides.

Abstract P4-03-08: Analyzing the clinical actionability of germline CYP2D6 polymorphism in Chinese breast cancer population

Background:Tamoxifen is effective for endocrine-responsive breast cancer as adjuvant therapy. CYP2D6 enzyme metabolizes tamoxifen to clinically active metabolites, while CYP2D6 polymorphisms may adversely affect tamoxifen efficacy by some retrospective clinical evidence. This study was carried out to estimate genotype frequencies of common variants of CYP2D6 in Chinese population. The relationship between prescription of selective estrogen receptor modulators (SERMs) and CYP2D6 polymorphism was also analyzed.

Methods: This was a retrospective research of early-stage patients who underwent surgical treatment at Fudan University Shanghai Cancer Center with ER+ and/or PR+ breast cancer. Genomic DNA was extracted from peripheral blood, which was used for genotyping CYP2D6*10 (C100T) single-nucleotide polymorphisms by polymerase chain reaction-based methods.

Results: A total of 312 patients with primary breast cancer were identified. More than 90.0% patients were in premenopausal status. The allele frequence of CYP2D6*10 in the Chinese population was 54.3%. The genotype frequencies of CYP2D6*10 were 20.5%, 50.3%, 29.2%, for wild-type, heterozygous and homozygous type respectively. We also found this SNP had no significant correlation with clinical characteristics. 145 patients were continuing endocrine treatment in first 5 years. 34.5% patients received CYP2D6 polymorphism test before the prescription of SERMs. The results significantly effected the choice of SERMs. Only 6.2% homozygous type patients took tamoxifen, 45.5% heterozygous patients chose tamoxifen, while 75.0% for wild type. 65.5% patients received CYP2D6 polymorphism test during the treatment of tamoxifen. 63.9% homozygous type patients switched to Toremifene, while 18.9% heterozygous patients changed the endocrine treatment.

Conclusions: The results showed that the frequence of CYP2D6*10 allele was high and nearly 30% Chinese breast cancer population were intermediate metabolizer for tamoxifen. The cyp2d6 polymorphism would influence prescription of SERM in premenopausal breast cancer patients. Patients with homozygous types should take other endocrine treatment instead of tamoxifen, which need more evidence of prospective clinical trials.

Citation Format: Huang L, Cao A. Analyzing the clinical actionability of germline CYP2D6 polymorphism in Chinese breast cancer population [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-03-08.

Perception of Special Needs Dentistry education and practice amongst Australian dental auxiliary students

INTRODUCTION

The role of dental auxiliaries in collaborative care of patients with special needs is compelling. This study was undertaken to investigate the perceptions of Special Needs Dentistry (SND) education and practice amongst students enrolled in Australian programmes in dental auxiliary, namely dental hygiene, dental therapy and oral health therapy (DH/DT/OHT).

MATERIALS AND METHODS

All Australian institutions offering DH/DT/OHT programmes (n = 14) were invited to participate in a self-administered questionnaire survey, conducted online, involving students across all academic years. Twelve institutions agreed to participate, but only five institutions were included in the final analysis, with a student response rate of 31.1%. Answers to open-ended questions were coded and grouped for measurement of frequencies. Quantitative data were analysed via chi-squared and Fisher's exact tests (significance taken as P < .05).

RESULTS

The majority of students could not define SND (87.0%) were not aware of the existence of this specialty (53.5%) and did not have clinical experience treating patients with special needs (68.9%). Nevertheless, they felt comfortable and positive about treating these patients independently. Most agreed that they should receive clinical and didactic education in SND, with many of them expressing interest in pursuing a specialty training in this field.

CONCLUSION

DH/DT/OHT students' comfort levels, positive attitudes and supportiveness for SND suggested positive implications for these practitioners to partake in multidisciplinary management of patients with special needs, thus indicating the need for standardised training requirements and practice guidelines in this area of care.

Molecular characterisation of the broad-spectrum resistance to powdery mildew conferred by the Stpk-V gene from the wild species Haynaldia villosa

A key member of the Pm21 resistance gene locus, Stpk-V, derived from Haynaldia villosa, was shown to confer broad-spectrum resistance to wheat powdery mildew. The present study was planned to investigate the resistance mechanism mediated by Stpk-V. Transcriptome analysis was performed in Stpk-V transgenic plants and recipient Yangmai158 upon Bgt infection, and detailed histochemical observations were conducted. Chromosome location of Stpk-V orthologous genes in Triticeae species was conducted for evolutionary study and over-expression of Stpk-V both in barley and Arabidopsis was performed for functional study. The transcriptome results indicate, at the early infection stage, the ROS pathway, JA pathway and some PR proteins associated with the SA pathway were activated in both the resistant Stpk-V transgenic plants and susceptible Yangmai158. However, at the later infection stage, the genes up-regulated at the early stage were continuously held only in the transgenic plants, and a large number of new genes were also activated in the transgenic plants but not in Yangmai158. Results indicate that sustained activation of the early response genes combined with later-activated genes mediated by Stpk-V is critical for resistance in Stpk-V transgenic plants. Stpk-V orthologous genes in the representative grass species are all located on homologous group six chromosomes, indicating that Stpk-V is an ancient gene in the grasses. Over-expression of Stpk-V enhanced host resistance to powdery mildew in barley but not in Arabidopsis. Our results enable a better understanding of the resistance mechanism mediated by Stpk-V, and establish a solid foundation for its use in cereal breeding as a gene resource.

Defensive changes in maize leaves induced by feeding of Mediterranean corn borer larvae

BACKGROUND

Plants can respond to insect attack via defense mechanisms that reduce insect performance. In this study, we examined the effects of several treatments applied to two maize genotypes (one resistant, one susceptible) on the subsequent growth and survival of Sesamia nonagrioides Lef. (Mediterranean corn borer, MCB) larvae. The treatments were infestation with MCB larvae, application of MCB regurgitant upon wounding, wounding alone, or exposure to methyl jasmonate, and they were applied at the V6-V8 stage of maize development. We also monitored changes in the concentrations of compounds known to be involved in constitutive resistance, such as cell wall-bound hydroxycinnamates and benzoxazinoids.

RESULTS

In both maize genotypes, the leaves of plants pre-infested with MCB larvae were less suitable for larval development than those from untreated plants. Application of MCB regurgitant upon wounding, and wounding itself, resulted in leaf tissues becoming less suitable for larval growth than those of pre-infested plants, suggesting that there could be herbivore-associated effector molecules that suppress some wounding responses. A single application of MCB regurgitant did not seem to mimic feeding by MCB larvae, although the results suggested that regurgitant deposited during feeding may have enhanced ferulates and diferulates synthesis in infested vs. control plants. Jasmonic acid may play a role in mediating the maize response to MCB attack, but it did not trigger hydroxycinnamate accumulation in the leaves to a level comparable to that induced by larval leaf feeding. The EP39 maize genotype showed an increase in leaf cell wall strength by increasing hemicellulose cross-linking in response to MCB attack, while induced defenses in the EP42 plants appeared to reflect a broader array of resistance mechanisms.

CONCLUSIONS

The results indicated that leaf feeding by MCB larvae can increase leaf antibiosis against MCB in two maize genotypes with contrasting levels of resistance against this borer. Also, the larval regurgitant played a positive role in eliciting a defense response. We determined the effects of the plant response on larval growth, and detected defense compounds related to borer resistance.

Protein expression profiling in haemocytes and plasma of the Manila clam Ruditapes philippinarum in response to infection with Perkinsus olseni

The protein expression profiling in clam haemocytes and plasma in response to Perkinsus olseni was addressed. Adult Manila clams from a P. olseni-free bed were experimentally challenged with parasite zoospores to analyse immune response. In another experiment, the effects of longer term infection were assessed in adult clams collected from a P. olseni-affected bed, by comparing moderate to very heavily infected clams with non-infected ones. Haemocyte and plasma proteins were separated by two-dimensional electrophoresis; spot patterns were qualitatively compared between treatments within each experiment and the spots indicating differential protein expression associated with P. olseni challenge or with field infection were processed for protein identification. Fifteen clam proteins (four in haemocytes and eleven in plasma) of which expression was markedly affected by P. olseni were identified. Some of the identified proteins have a well-known role in clam immune response against the parasite, such as lysozyme and lectins. Rho GTPase-activating protein 6 could be a marker of resistance against P. olseni, which should be further studied.

Selective Sparing of Human Tregs by Pharmacologic Inhibitors of the Phosphatidylinositol 3-Kinase and MEK Pathways

Phosphatidylinositol 3-kinase (PI3K) and mitogen-activated protein kinase/extracellular signal-regulated (MEK) signaling are central to the survival and proliferation of many cell types. Multiple lines of investigation in murine models have shown that control of the PI3K pathway is particularly important for regulatory T cell (Treg) stability and function. PI3K and MEK inhibitors are being introduced into the clinic, and we hypothesized that pharmacologic inhibition of PI3K, and possibly MEK, in mixed cultures of human mononuclear cells would preferentially affect CD4(+) and CD8(+) lymphocytes compared with Tregs. We tested this hypothesis using four readouts: proliferation, activation, functional suppression, and signaling. Results showed that Tregs were less susceptible to inhibition by both δ and α isoform-specific PI3K inhibitors and by an MEK inhibitor compared with their conventional CD4(+) and CD8(+) counterparts. These studies suggest less functional reliance on PI3K and MEK signaling in Tregs compared with conventional CD4(+) and CD8(+) lymphocytes. Therefore, the PI3K and MEK pathways are attractive pharmacologic targets for transplantation and treatment of autoimmunity.

Efficacy and safety of titrated canagliflozin in patients with type 2 diabetes mellitus inadequately controlled on metformin and sitagliptin

AIMS

To evaluate the efficacy and safety of titrated canagliflozin, a sodium glucose co-transporter 2 inhibitor, in patients with type 2 diabetes mellitus (T2DM) inadequately controlled on metformin and sitagliptin.

METHODS

In this randomized, double-blind study, patients with T2DM (N = 218) on metformin ≥1500 mg/day and sitagliptin 100 mg received canagliflozin 100 mg or placebo. After 6 weeks, the canagliflozin dose was increased from 100 to 300 mg (or from placebo to matching placebo) if all of the following criteria were met: baseline estimated glomerular filtration rate ≥70 ml/min/1.73 m(2) ; fasting self-monitored blood glucose ≥5.6 mmol/l (≥100 mg/dl); and no volume depletion-related adverse events (AEs) within 2 weeks before dose increase. Endpoints included change in glycated haemoglobin (HbA1c) at week 26 (primary); proportion of patients achieving HbA1c <7.0%; and changes in fasting plasma glucose (FPG), body weight and systolic blood pressure (SBP). Safety was assessed using AE reports.

RESULTS

Overall, 85.4% of patients were titrated to canagliflozin 300 mg or matching placebo (mean ± standard deviation time to titration 6.2 ± 0.8 weeks). At week 26, canagliflozin (pooled 100 and 300 mg) demonstrated superiority in HbA1c reduction versus placebo (-0.91% vs. -0.01%; p < 0.001). Canagliflozin provided significant reductions in FPG, body weight and SBP compared with placebo (p < 0.001). The overall AE incidence was 39.8 and 44.4% for canagliflozin and placebo, respectively. Canagliflozin was associated with an increased incidence of genital mycotic infections.

CONCLUSIONS

Titrated canagliflozin significantly improved HbA1c, FPG, body weight and SBP, and was generally well tolerated over 26 weeks in patients with T2DM as add-on to metformin and sitagliptin.

Genetic Factors Involved in Fumonisin Accumulation in Maize Kernels and Their Implications in Maize Agronomic Management and Breeding

Contamination of maize with fumonisins depends on the environmental conditions; the maize resistance to contamination and the interaction between both factors. Although the effect of environmental factors is a determinant for establishing the risk of kernel contamination in a region, there is sufficient genetic variability among maize to develop resistance to fumonisin contamination and to breed varieties with contamination at safe levels. In addition, ascertaining which environmental factors are the most important in a region will allow the implementation of risk monitoring programs and suitable cultural practices to reduce the impact of such environmental variables. The current paper reviews all works done to address the influence of environmental variables on fumonisin accumulation, the genetics of maize resistance to fumonisin accumulation, and the search for the biochemical and/or structural mechanisms of the maize plant that could be involved in resistance to fumonisin contamination. We also explore the outcomes of breeding programs and risk monitoring of undertaken projects.

Critical environmental and genotypic factors for Fusarium verticillioides infection, fungal growth and fumonisin contamination in maize grown in northwestern Spain

In northwestern Spain, where weather is rainy and mild throughout the year, Fusarium verticillioides is the most prevalent fungus in kernels and a significant risk of fumonisin contamination has been exposed. In this study, detailed information about environmental and maize genotypic factors affecting F. verticillioides infection, fungal growth and fumonisin content in maize kernels was obtained in order to establish control points to reduce fumonisin contamination. Evaluations were conducted in a total of 36 environments and factorial regression analyses were performed to determine the contribution of each factor to variability among environments, genotypes, and genotype × environment interactions for F. verticillioides infection, fungal growth and fumonisin content. Flowering and kernel drying were the most critical periods throughout the growing season for F. verticillioides infection and fumonisin contamination. Around flowering, wetter and cooler conditions limited F. verticillioides infection and growth, and high temperatures increased fumonisin contents. During kernel drying, increased damaged kernels favored fungal growth, and higher ear damage by corn borers and hard rainfall favored fumonisin accumulation. Later planting dates and especially earlier harvest dates reduced the risk of fumonisin contamination, possibly due to reduced incidence of insects and accumulation of rainfall during the kernel drying period. The use of maize varieties resistant to Sitotroga cerealella, with good husk coverage and non-excessive pericarp thickness could also be useful to reduce fumonisin contamination of maize kernels.

Abstract S4-04: Overcoming resistance to PI3K inhibitors in PIK3CA mutant breast cancer using CDK4/6 inhibition: Results from a combinatorial drug screen

Various components of the phosphatidylinositol 3-kinase (PI3K) pathway are deregulated across a spectrum of human cancers. Notably, cancers with PIK3CA mutations, seen in roughly 30% of breast cancers, are amongst the most sensitive to PI3K inhibitors (PI3Ki) as single agents. Therefore, there have been great efforts to develop PI3K inhibitors specifically for these types of cancers, and many agents have already entered the clinic.

Although initial responses and prolonged stable disease have been observed, resistance frequently emerges. Moreover, there is a subset of PIK3CA mutated cancers that unexpectedly do not exhibit an initial response or disease stabilization upon exposure to PI3K inhibitors, despite presence of the mutation. These cancers are said to have de novo resistance to PI3K inhibition. To determine methods of overcoming resistance to PI3K inhibitors, we generated two models with acquired resistance to the p110a isoform specific inhibitor BYL-719 (BYL) using MDA-MB-453 (453) and T47D. We also established one model of resistance to the pan-PI3K inhibitor GDC-0941 using MCF7 cells. These lines were chosen because of their PIK3CA mutated status and sensitivity to PI3K inhibition. Each cell line was grown in increasing concentrations of PI3K inhibitor until the cells proliferated readily at a dose of drug that effectively reduced cell viability and inhibited pAKT in the sensitive parental cell lines. Interestingly, both BYL resistant cells (453R and T47DR) were cross resistant GDC and the MCF7R line was refractory to BYL.

To elucidate mechanisms to overcome resistance to PI3K inhibitors, we undertook a combinatorial drug screen, in which PI3K inhibitor resistant cells were treated with escalating doses of a panel of 45 targeted agents, both in the presence and absence of a fixed dose of PI3Ki, to determine which agents synergized effectively with PI3K inhibition in these resistant cells. We observed in each of the three PI3Ki resistant models a synergy between the CDK4/6 inhibitor LEE-011 and PI3K inhibition. We furthermore tested this combination of agents in a PIK3CA mutated breast cancer model with de novo resistance to PI3K inhibitors, CAL51, and again noted efficacy with the combination of GDC and LEE-011 while either agent on its own displayed minimal activity.

To determine whether addition of CDK 4/6 inhibition might be an effective addition to PI3Ki in the upfront setting in vivo, we injected each of the PIK3CA mutated lines MCF7, 453, and T47D into female nude mice and treated with vehicle, BYL, LEE-011, or the combination. We noted in each of the three models that the combination of agents, led to tumor regression that was more substantial than single agent treatment, and furthermore delayed the acquisition of resistance relative to single agent therapy. We furthermore tested GDC with LEE-011 singly and in combination in both MCF7 and CAL51 xenografts and again noted that the combination of agents led to tumor regression, whereas in these instances, single agent treatment did not.

We conclude that the combination of PI3K and CDK 4/6 inhibition may be an effective strategy for treating PIK3CA mutated breast cancer and deserves further study in the clinical setting.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr S4-04.

Is it possible to control fumonisin contamination in maize kernels by using genotypes resistant to the Mediterranean corn borer?

Insect activity has long been associated with Fusarium infection. The objectives of the current study were 1) to estimate the impact of Mediterranean corn borer, Sesamia nonagrioides Lefèbvre, damage on fumonisin contamination in the maize kernel by comparing fumonisin contamination under infestation and protected conditions, and 2) to measure the potential use of genotypes resistant to this borer as controlling factors of fumonisin contamination. Genotypes with increased kernel damage by borers tended to increase fumonisin accumulation under infestation conditions. In particular environments, other factors influenced fumonisin contamination more than damage by borers. When ear damage by borers is significant, maize resistance to ear damage could contribute to the reduction of fumonisin contamination in the kernels. Genotype such as EP42 x EP77 that combines low ear damage by borers and low fumonisin level across environments is a good choice to control fumonisin contamination. The use of an applicable methodology to identify Mediterranean corn borer-resistant genotypes to ear attack under artificial infestations might be a promising approach.

Environmental factors related to fungal infection and fumonisin accumulation during the development and drying of white maize kernels

In Southern Europe where whole maize kernels are ground and used for making bread and other food products, infection of the kernels by Fusarium verticillioides and subsequent fumonisin contamination pose a serious safety issue. The influence of environmental factors on this fungal infection and mycotoxin accumulation as the kernel develops has not been fully determined, especially in such food grade maize. The objectives of the present study were to determine which environmental factors may contribute to kernel invasion by F. verticillioides and fumonisin accumulation as kernels develop and dry in naturally infected white maize. Three maize hybrids were planted at two different sowing dates and kernel samples were collected 20, 40, 60, 80 and 100 days after silking. The percentage of kernels infected, and ergosterol and fumonisin contents were recorded for each sampling. F. verticillioides was the most prevalent species identified as the kernels developed. Temperature and moisture conditions during the first 80 days after silking favored natural kernel infection by F. verticillioides rather than by Aspergillus or Penicillium species. Fumonisin was found in kernels as early as 20 days after silking however significant fumonisin accumulation above levels acceptable in the EU did not occur until after physiological maturity of the kernel indicating that kernel drying in the field poses a high risk. Our results suggest that this could be due to increasing kernel damage by insects that favor fungal development, such as the damage by the moth Sitotroga cerealella, and to the occurrence of stress conditions for F. verticillioides growth that could trigger fumonisin biosynthesis, such as exposure to suboptimal temperatures for growth simultaneously with low water activity.

Role of hydroxycinnamic acids in the infection of maize silks by Fusarium graminearum Schwabe

In the current study, the hydroxycinnamic acids in silks of diverse maize inbred lines differing in Fusarium resistance were determined at several times after inoculation with Fusarium graminearum or sterile water as control. The main objective was to determine the possible relationship between the hydroxycinnamic acid changes in silks and ear rot resistance. Several changes in the cell-wall-bound hydroxycinnamic acid concentrations were observed after inoculation with F. graminearum, although these changes were not directly correlated with genotypic resistance to this fungus. Ester-bound ferulic acid decreased, probably due to degradation of hemicellulose by hydrolytic enzymes produced by Fusarium spp., while p-coumaric acid and diferulates showed slight increases that, in conjunction, did not result in delayed F. graminearum progression through the silks. It is important to note that the decrease of ferulic acid in the F. graminearum treatment was faster in susceptible than in resistant genotypes, suggesting a differential hemicellulose degradation in silk tissues. Therefore, the ability of the maize genotypes to slow down that process through hemicellulose structural features or xylanase inhibitors needs to be addressed in future studies.

Expression of mutant protein p53 and Hsp70 and Hsp90 chaperones in cockles Cerastoderma edule affected by neoplasia

High prevalence of disseminated neoplasia has been found in cockles Cerastoderma edule of Galicia (NW Spain). Disseminated neoplasia has been associated with high mortalities of various bivalve species. In vertebrates, proteins such as p53 and heat shock proteins (HSPs) play important roles in carcinogenesis. The protein p53 has been detected in neoplastic cells of bivalve molluscs such as Mytilus edulis, Mytilus trossulus, Mya arenaria, Spisula solidissima, Crassostrea rhizophorae and Crassostrea gigas. In this study, western blotting analyses were used to test the expression of Hsp70, Hsp90 and mutant p53 proteins in the cells and plasma of the haemolymph of cockles showing various intensities of neoplasia. Disseminated neoplasia was previously diagnosed by examination of stained haemolymph monolayers with light microscopy. In the present study, mutant p53 was detected in haemolymph cells of cockles diagnosed as affected by moderate and heavy neoplasia intensity, whereas it was not detected in cockles with either no or light neoplasia. The higher the neoplasia intensity, the higher the levels of Hsp70 and Hsp90. These proteins were not found in plasma. The results reveal the possible association between p53 and HSPs in neoplastic cells of cockles, which could prevent p53 from carrying out its functions, as occurs in human cancers.

A novel missense mutation (C84R) in a patient with type II vitamin d-dependent rickets

A 7-year-old boy with severe rickets that by clinical analysis was diagnosed as affected by type II vitamin D-dependent rickets, was evaluated for mutations in the vitamin D receptor gene (VDR). The molecular analysis showed a homozygous state for a novel missense mutation (C84R) in a highly conserved nucleotide in the second Zn finger of the DNA binding domain.

Age- and gender-specific awareness, treatment, and control of cardiovascular risk factors and subclinical vascular lesions in a founder population: the SardiNIA Study

AIM

We investigated the gender-specific control of cardiovascular (CV) risk factors and subclinical vascular lesions in a founder population in Italy.

METHODS AND RESULTS

6148 subjects were enrolled (aged 14-102 years) from four towns. Hypertension (HT), diabetes mellitus (DM) and dyslipidemia (LIP) were defined in accordance with guidelines. A self-reported diagnosis defined awareness of these conditions, and the current use of specific medications as treatment. Prevalence was HT 29.2%, DM 4.8%, LIP 44.1% and was higher in men than in women. Disease prevalence increased with age for every CV risk factor. Men were less likely than women to take anti-HT drugs and to reach BP control (9.9% vs. 16%). Only 17.6% of HT > 65 years had a BP < or =140/90 mmHg, though 48.5% were treated. The use of statins was very low (<1/3 of eligible subjects > 65 years, those with the highest treatment rate). The ratio of control-to-treated HT was lower in subjects with, than in those without, thicker carotid arteries (31.5% vs. 38.8%, p < 0.05) or stiffer aortas (26.0% vs. 40.0%, p < 0.05) or carotid plaques (26.3% vs. 41.1%, p<0.05).

CONCLUSION

A large number of subjects at high CV risk are not treated and the management of subclinical vascular lesions is far from optimal.

Hemoglobin Constitution of Double Heterozygotes for α or β-Thalassemia and HB J Sardegna

In this study, we carried out alpha-globin gene mapping in 12 heterozygotes for Hb J Sardegna and in 5 double heterozygotes for this variant and beta-thalassemia. Then, we correlated the Hb pattern with the alpha and beta-globin genotype. In heterozygotes for Hb J Sardegna with a deletion of a single alpha-globin gene (alpha alpha/-alpha) the amount of the abnormal Hb was significantly (p much less than 0.001) higher than in heterozygotes for this variant with a full complement of 4 alpha-globin structural genes (27.5% versus 20.4%). Double heterozygotes for the abnormal hemoglobin and beta-thalassemia with a full complement of 4 alpha-globin structural genes tended to have lower amount of the abnormal Hb than heterozygotes for this variant who do not have beta-thalassemia.

Modifications in the Head Group and in the Spacer of Cholesterol-based Cationic Lipids Promote Transfection in Melanoma B16-F10 Cells and Tumours

A series of four cationic lipids derived from cholesterol was synthesised and their efficiencies to vectorise nucleic acids were compared. The investigation concerns the effects of systematic chemical modifications in the polar head and in the spacer. The cationic lipid molecules used are in the same family of 3beta[N-(N',N',N'-trimethylaminoethane)-carbamoyl] cholesterol iodide (TMAEC-Chol), presenting a spacer of two or three carbons and a quaternary ammonium polar head ramified with methyl or ethyl groups. These lipids formed stable liposomes sizing from 100 to 200 nm when prepared with the colipid dioleoyl phosphatidylethanolamine (DOPE). The goal of this work was to investigate the effect of the chemical structure of these cationic lipids on lipofection. Their ability to form complexes with DNA, their cytotoxicity and their transfection efficiency in vitro and in vivo were studied. Results were compared with those obtained from the well known cholesterol-based cationic lipid DC-Chol. In a melanoma cell line (B16-F10), results showed that either the polar head or the spacer affected the cytotoxicity. Cationic lipids with three ethyl groups in the head are more toxic than those with three methyl groups while cationic lipids with three carbons in the spacer are less toxic than those with two carbons in the spacer. The best transfection level was obtained in vitro and in vivo with cationic lipids having 3C in the spacer. Data indicated that among these lipids, in vivo gene transfer is advantaged by the methylated polar head while in vitro the best level was obtained with the ethylated one. Finally, it was observed that the chemical structure influences the transfection in the presence of serum while the complex charge and the DOPE ratios in liposomes preferentially affect the interaction with erythrocytes. Argumentations are proposed to explain the discrepancies between in vitro and in vivo transfection results concerning the optimal charge ratio and the chemical nature of the cationic lipid head group.

Variable dystrophin expression in different muscles of a Duchenne muscular dystrophy carrier

The majority of Duchenne muscular dystrophy (DMD) female carriers show dystrophin immunostaining abnormalities, although a significant proportion of clinically non-manifesting carriers are normal following this analysis. We had the opportunity to study dystrophin immunostaining in two different muscles, the vastus lateralis and the rectus abdominis of a possible DMD carrier. While the vastus showed normal dystrophin immunostaining, pathological staining was detected in her rectus abdominis. These findings seem to indicate that dystrophin expression can vary in different muscle groups of a DMD carrier. The implications of these findings in DMD carrier detection and possible dystrophin function are discussed.

Thalassaemia and glucose-6-phosphate dehydrogenase screening in 13- to 14-year-old students of the Sardinian population: preliminary findings

OBJECTIVES

In this paper we describe the outline and results of a 7-year screening programme for thalassaemias and glucose-6-phosphate dehydrogenase (G6PD) deficiency in 13- to 14-year-old students from the Sardinian population.

METHOD

This programme had several steps: formal education on thalassaemia, request of informed consent by parents, blood testing and genetic counselling.

RESULTS

Out of 63,285 subjects tested, 6,521 (10.3%) were heterozygotes for beta-thalassaemia, 16,175 (25.6%) for alpha-thalassaemia and 101 were carriers of a haemoglobin variant. One thousand four hundred and twenty (16.4%) males were hemizygotes for G6PD deficiency and 1,893 (20.6%) females were heterozygotes.

CONCLUSION

The uptake of the programme was remarkably high and homogeneous across the island, indicating and confirming a great interest of the Sardinian population in any initiative directed at the prevention of homozygous beta-thalassaemia.

Eye gaze tracking for endoscopic camera positioning: an application of a hardware/software interface developed to automate Aesop

A redesigned motion control system for the medical robot Aesop allows automating and programming its movements. An IR eye tracking system has been integrated with this control interface to implement an intelligent, autonomous eye gaze-based laparoscopic positioning system. A laparoscopic camera held by Aesop can be moved based on the data from the eye tracking interface to keep the user's gaze point region at the center of a video feedback monitor. This system setup provides autonomous camera control that works around the surgeon, providing an optimal robotic camera platform.

Control of beta-thalassaemia by carrier screening, genetic counselling and prenatal diagnosis: the Sardinian experience

Homozygous beta-thalassaemia in a number of at-risk populations (Greek and Turkish Cypriots, Greeks, Continental Italians and Sardinians) has been prevented at the population level by programmes based on carrier screening, genetic counselling and prenatal diagnosis. The Sardinian experience is based on a 20-year programme. Voluntary screening has been offered to prospective parents and, primarily, to women with an ongoing pregnancy. Education of the population at large, training of health personnel, and use of posters and informative booklets have been critical elements for the success of the programme. Genetic counselling has been carried out in a non-directive manner following well-established guidelines. The use of extended family screening magnified the efficacy of the screening programme, allowing the identification of the large majority of parents at risk by screening only 13% of the population at child-bearing age. Following counselling, the large majority of parents accepted prenatal diagnosis. Definition of the parents' mutation and prenatal diagnosis were carried out by a number of PCR-based procedures. The programme was effective, as indicated by the reduction of the birth rate of thalassaemia major from 1:250 live births to 1:4000.

Activity of MVA 5T4 alone or in combination with either interleukin-2 (IL-2) or interferon-α (IFN) in patients (Pts) with metastatic renal cell cancer (MRCC)

3069

Background: MVA 5T4 consists of the highly attenuated modified Vaccinia Ankara virus containing the gene encoding the human TAA 5T4. Ninety percent or more of RCCs overexpress the 5T4 antigen. A series of clinical trials were conducted to evaluate the effectiveness of MVA 5T4 as a single agent or in combination with Interleukin-2 or Interferon Alpha 2B. Methods: Eligibility: pathologic diagnosis of clear cell or papillary RCC, progressive measurable metastases, any prior therapy, adequate physiologic parameters, Karnofsky performance status (KPS) = 80%, and no active CNS involvement. A regimen of MVA 5T4 alone or in combination with IFN or IL-2 was given. Results: A total of 41 patients received MVA 5T4 alone or in combination. 33 patients received MVA 5T4 with low dose IL-2 or IFN. 23 pts had clear cell; 12 papillary; 5 mixed clear cell; and 1 mixed papillary. 19 pts continue to receive therapy. 2 pts (both clear cell RCC) developed complete responses, 3 pts/partial responses (2 clear cell, 1 papillary) 8 pts/stable for 3+months and 6 pts are too early to be staged at this time. Median duration of therapy is 3.0+ (1+-13+) months. Conclusion: Although comparable antibody response were observed in papillary and clear cell histotypes, clear cell patients appeared to be more likely to respond in terms of clinical benefit parameters, to be presented. Of note is that preliminary analysis of clear cell patients suggests a relationship between the anti-5T4 immune response and tumor response. With the immunological potency and encouraging clinical activity, the future research will focus on the phase 3 randomized, double-blind, placebo controlled parallel group study to investigate whether MVA 5T4, added to first line standard of care therapy, prolongs the survival of patients with locally advanced or metastatic clear cell as well as studies to further optimize MVA 5T4 potency.

[Table: see text]

An atlas-based method to compensate for brain shift: preliminary results

Compensating for intraoperative brain shift using computational models has shown promising results. Since computational time is an important factor during neurosurgery, a priori knowledge of the possible sources of deformation can increase the accuracy of model-updated image-guided systems. In this paper, a strategy to compensate for distributed loading conditions in the brain such as brain sag, volume changes due to drug reactions, and brain swelling due to edema is presented. An atlas of model deformations based on these complex loading conditions is computed preoperatively and used with a constrained linear inverse model to predict the intraoperative distributed brain shift. This relatively simple inverse finite-element approach is investigated within the context of a series of phantom experiments, two in vivo cases, and a simulation study. Preliminary results indicate that the approach recaptured on average 93% of surface shift for the simulation, phantom, and in vivo experiments. With respect to subsurface shift, comparisons were only made with simulation and phantom experiments and demonstrated an ability to recapture 85% of the shift. This translates to a remaining surface and subsurface shift error of 0.7+/-0.3 mm, and 1.0+/-0.4 mm, respectively, for deformations on the order of 1cm.

Hand position effects on precision and speed in telerobotic surgery

BACKGROUND

Many surgical robotic interfaces allow users to interact with robots over a wide potential range of motion, yet variation in operator performance across a range of motion remains unexamined. This research identifies and explores a new construct, the surgeon's 'comfortable working envelope' within the available range of motion, as a factor in surgical robotic interface design.

METHODS

Task accuracy and completion time for a simple aimed movement task were analysed as a function of participant hand positions obtained via infrared motion tracking.

RESULTS

Hand positions outside the 'comfortable working envelope' led to a 20% increase in error magnitude. With respect to the overall input device range of motion, there were large variations in performance, up to 31% difference in error magnitude and 11% difference in movement time.

CONCLUSIONS

These results suggest that advanced surgical robots should have intelligent re-indexing strategies. Alternatively, the robot's control gain should adaptively change with respect to hand position to normalize a surgeon's performance throughout his/her working volume.