Nitrogen use efficiency is regulated by interacting proteins relevant to development in wheat

Wheat (Triticum aestivum) has low nitrogen use efficiency (NUE). The genetic mechanisms controlling NUE are unknown. Positional cloning of a major quantitative trait locus for N-related agronomic traits showed that the vernalization gene TaVRN-A1 was tightly linked with TaNUE1, the gene shown to influence NUE in wheat. Because of an Ala180 /Val180 substitution, TaVRN-A1a and TaVRN-A1b proteins interact differentially with TaANR1, a protein encoded by a wheat orthologue of Arabidopsis nitrate regulated 1 (ANR1). The transcripts of both TaVRN-A1 and TaANR1 were down-regulated by nitrogen. TaANR1 was functionally characterized in TaANR1::RNAi transgenic wheat, and in a natural mutant with a 23-bp deletion including 10-bp at the 5' end of intron 5 and 13-bp of exon 6 in gDNA sequence in its gDNA sequence, which produced transcript that lacked the full 84-bp exon 6. Both TaANR1 and TaHOX1 bound to the Ala180 /Val180 position of TaVRN-A1. Genetically incorporating favourable alleles from TaVRN-A1, TaANR1 and TaHOX1 increased grain yield from 9.84% to 11.58% in the field. Molecular markers for allelic variation of the genes that regulate nitrogen can be used in breeding programmes aimed at improving NUE and yield in novel wheat cultivars.

Mis-Spliced Lr34 Transcript Events in Winter Wheat

Lr34 in wheat is a non-race-specific gene that confers resistance against multiple fungal pathogens. The resistant allele Lr34 and the susceptible allele Lr34s can be distinguished by three polymorphisms that cause alternation of deduced amino acid sequences of Lr34 at the protein level. In seedlings of a cultivar carrying the resistant Lr34r allele, only a portion (35%) of its transcripts was correctly spliced and the majority (65%) of its transcripts were incorrectly spliced due to multiple mis-splicing events. Lr34 mis-splicing events were also observed at adult plant age when this gene exerts its function. All of the mis-spliced Lr34r cDNA transcripts observed in this study resulted in a premature stop codon due to a shift of the open reading frame; hence, the mis-spliced Lr34r cDNAs were deduced to encode incomplete proteins. Even if a cultivar has a functional Lr34 gene, its transcripts might not completely splice in a correct pattern. These findings suggested that the partial resistance conferred by a quantitative gene might be due to mis-splicing events in its transcripts; hence, the resistance of the gene could be increased by eliminating or mutating regulators that cause mis-splicing events in wheat.

LXW7 ameliorates focal cerebral ischemia injury and attenuates inflammatory responses in activated microglia in rats

Inflammation plays a pivotal role in ischemic stroke, when activated microglia release excessive pro-inflammatory mediators. The inhibition of integrin αvβ3 improves outcomes in rat focal cerebral ischemia models. However, the mechanisms by which microglia are neuroprotective remain unclear. This study evaluated whether post-ischemic treatment with another integrin αvβ3 inhibitor, the cyclic arginine-glycine-aspartic acid (RGD) peptide-cGRGDdvc (LXW7), alleviates cerebral ischemic injury. The anti-inflammatory effect of LXW7 in activated microglia within rat focal cerebral ischemia models was examined. A total of 108 Sprague-Dawley rats (250–280 g) were subjected to middle cerebral artery occlusion (MCAO). After 2 h, the rats were given an intravenous injection of LXW7 (100 μg/kg) or phosphate-buffered saline (PBS). Neurological scores, infarct volumes, brain water content (BWC) and histology alterations were determined. The expressions of pro-inflammatory cytokines [tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1β)], and Iba1-positive activated microglia, within peri-ischemic brain tissue, were assessed with ELISA, western blot and immunofluorescence staining. Infarct volumes and BWC were significantly lower in LXW7-treated rats compared to those in the MCAO + PBS (control) group. The LXW7 treatment lowered the expression of pro-inflammatory cytokines. There was a reduction of Iba1-positive activated microglia, and the TNF-α and IL-1β expressions were attenuated. However, there was no difference in the Zea Longa scores between the ischemia and LXW7 groups. The results suggest that LXW7 protected against focal cerebral ischemia and attenuated inflammation in activated microglia. LXW7 may be neuroprotective during acute MCAO-induced brain damage and microglia-related neurodegenerative diseases.

Quantitative Trait Loci Mapping for Tillering-Related Traits in Two Switchgrass Populations

Plant tillering and related traits are morphologically important components contributing to switchgrass ( L.) biomass yield. The objectives of this study were to estimate broad-sense heritabilities for tillering-related traits, to analyze correlations between biomass yield and the traits, and to identify quantitative trait loci (QTL) for them. A first-generation selfed population of NL94 plant and a hybrid population between NL94 and SL93 plants were field established in a randomized complete block design with three replications in Stillwater and Perkins, OK. Phenotypic data were collected in 2 yr and genotypic data were obtained by genotyping simple-sequence repeat (SSR) markers in the two populations on the basis of two preexisting genetic maps. Plant base size (PBS), plant girth (PG), tillering ability (TA), tiller diameter (TD), and tiller dry weight (TDW) were positively correlated with biomass yield in both populations. Consistently, PBS had the largest correlation coefficients for biomass yield, suggesting its value as an indirect selection criterion for biomass yield. Twenty and 26 QTL for six tillering-related traits were detected in the hybrid and selfed population, respectively. Among the QTL, one on linkage group (LG) 5a between sww-2387/PVCAG-2197/2198 and PVGA-1649/1650 for PBS, PG, and TA and another on LG 2a between sww-2640/sww-2545 and PVCA-765/766 for TD and TDW were stably detected in multiple environments in the two populations. The findings add to the knowledge base regarding the genetics of tillering-related traits that could be used in accelerating the development of high-yielding cultivars through marker-assisted selection.

[Efficiency of integrin αvβ3 inhibitor Cilengitide in acute cerebral ischemia in rats]

OBJECTIVE

To explore the effect of the integrin αvβ3 inhibitor Cilengitide on the blood brain barrier (BBB) permeability, brain edema, neuronal cell apoptosis and the relation with the vascular endothelial growth factor (VEGF)expression in acute cerebral ischemia rats.

METHODS

A rat focal cerebral ischemia/reperfusion model was established by middle cerebral artery occlusion. Rats with middle cerebral artery occlusion, in accordance with the random number table, were divided into four groups: (1) the rats in Cilengitide group A (n=30) were treated with Cilengitide at a dose of 100 μg/kg; (2) the rats in Cilengitide group B (n=28) were treated with Cilengitide at a dose of 200 μg/kg; (3) the rats in sham group (n=31), without inserting thread into middle cerebral artery, were treated with normal saline; (4) the rats in control group (n=27) were treated with normal saline.All rats were treated with Cilengitide or saline 1 hour after infarction, given reperfusion 2 hours after infarction and were sacrificed 22 hours after reperfusion.The brain-water content was measured by dry/wet weight method. The permeability of BBB was measured by quantifying Evans Blue. The infarction volume was measured by 2, 3, 5-tripheyl tetrazolium Chloride (TTC) staining. Expression level of VEGF, P-Flk, Cleaved-Caspase-3 was measured by immunohistochemistry and Western blot, respectively.The neuronal cell apoptosis was evaluated by terminal deoxynucleotidyl transferased UTP nick end labeling (TUNEL).

RESULTS

Compared with Control group, treatment groups with cilengitide at the dose of 100 μg/kg and 200 μg/kg reduced brain-water content [(80.8±1.1)% vs (84.8±1.4)%, (81.0±1.4)% vs (84.8±1.4)%, P<0.05], reduced exudation of Evans blue[(9.2±1.1) μg/g vs (12.2±0.8) μg/g, (8.6±0.6) μg/g vs (12.2±0.8) g/g, P<0.05], reduced infarction volume[(31.9±4.9) mm(3) vs(43.0±2.2) mm(3), (29.2±3.5) mm(3) vs(43.0±2.2) mm(3), P<0.05] , reduced neuronal cell apoptosis [(36±4)vs(69±6)、(35±3)vs (69±6), P<0.05]. Compared with sham group, Cilengitide group A and Cilengitide group B had lower brain-water content, permeability of BBB, infarction volume, expression level of VEGF, P-Flk, Cleaved-Caspase-3 and neuronal cell apoptosis (P<0.05). When Cilengitide group A was compared with Cilengitide group B, there were no significant differences in brain-water content, permeability of BBB, infarction volume, expression level of VEGF, P-Flk, Cleaved-Caspase-3 and neuronal cell apoptosis (P>0.05).

CONCLUSION

The integrin αvβ3 inhibitor Cilengitide improves outcomes in the MCAO model by preserving the blood-brain barrier, attenuating brain edema and inhibiting neuronal cell apoptosis, which may occur in a VEGF-and VEGF-receptor-dependent manner, with the same efficacy between Cilengitide 100 μg/kg and 200 μg/kg after 23 hours treatment.

Effects of humic acid and ionic strength on TiO₂ nanoparticles sublethal toxicity to zebrafish

The stability and bioavailability of titanium dioxide nanoparticles (TiO2 NPs) suspension could be modified by the physicochemical properties of solution. In the present study, the effect of humic acid (HA) and ionic strength (by adding NaCl) on aggregation and sedimentation of TiO2 NPs suspension were investigated. Accordingly, the sublethal toxicity of TiO2 NPs suspensions with different HA and NaCl concentrations toward zebrafish (Danio rerio) was evaluated by monitoring the changes of superoxide dismutase, catalase, malonaldehyde and glutathione in gill, liver and intestine. The results showed that the aggregations formation and hydrodynamic diameter of TiO2 NPs in suspensions are not essential characteristics to decide toxicity. The varied oxidative stress responses detected in gill, liver and intestine derived from different toxicity mechanisms of TiO2 NPs. Nevertheless, the oxidative stress could be suppressed by the adding of HA and/or the increase of ionic strength, which can decrease the bioavailability of TiO2 NPs in water. The study suggests that the environmental factors, such as HA and ionic strength, are important for the fate (aggregation and sedimentation) and toxicity of nanomaterials in aquatic environment.

Vernalization requirement duration in winter wheat is controlled by TaVRN-A1 at the protein level

Winter wheat requires a period of low temperatures to accelerate flowering (vernalization). This requirement could make winter wheat more vulnerable to elevated global temperature via insufficient vernalization. All known vernalization genes are cloned according to qualitative variation in vernalization requirement between spring and winter wheat, but the genes controlling quantitative variation for more or less vernalization requirement among winter wheat cultivars remain unknown. We report here that the gene for the vernalization requirement duration in winter wheat was cloned using a BC(1)F(2:3) population that segregated in a 3:1 ratio of early-flowering plants and late-flowering plants after vernalization for 3 weeks. The positional cloning of the gene for vernalization requirement duration demonstrated that this trait is controlled by TaVRN-A1 at the protein level. The Ala(180) in vrn-A1a, encoded by the dominant allele for 3-week vernalization, was mutated to Val(180) in vrn-A1b, encoded by the recessive allele for 6-week vernalization. Further studies with in vitro protein pull-down assays and immunoprecipitation analyses indicated that the mutated Val(180) in vrn-A1b protein decreased the ability to bind with TaHOX1 (the first homeobox protein in Triticum aestivum). The direct binding of TaVRN-A1 and TaHOX1 proteins was confirmed in the nucleus of living plant cells by bimolecular fluorescence complementation (BiFC) analyses. The TaHOX1 gene was found to be upregulated by low temperatures, and to have a significant genetic effect on heading date, suggesting that TaHOX1 functions in the flowering pathway in winter wheat.

Liquid immiscibility in an Fe-Cu alloy by molecular dynamics simulation

Liquid-liquid phase segregation in an Fe-Cu melt is investigated by molecular dynamics (MD) simulation based upon a newly developed embedded atom method due to Bonny. The partial pair correlation functions (PPCF) of liquid Fe(50)Cu(50) at a temperature of 1873 K show stronger interaction of homogeneous atom pairs. The coordination number (CN) of Cu-Cu and Fe-Fe in Fe(50)Cu(50) melt is about 11, much higher than that of Fe-Cu. Liquid-liquid phase segregation has also been observed clearly by the atom snapshot method. The calculated enthalpy of mixing is positive in the whole concentration range and the Bhatia-Thornton (BT) structure factor S(CC)(q) increases sharply at lower q, which are all typical features of dense fluid that exhibits a phase segregation tendency. Our present work provides an understanding of atomic-scale phase segregation in liquid Fe-Cu alloy.

Effects of Molecular Rigidity on Electric Field Induced Alignment and Orientational Stability of Dipolar Chromophore Composites

The relationship between the supramolecular conformational structure of assembled chromophores and their susceptibility to electric field poling is of interest for maximizing the bulk alignment achievable in an electro-optic material. We have employed solution phase dielectric constant measurements to investigate possible enhancements in dipolar susceptibility as a function of connectivity and state of aggregation in rationally synthesized chromophore assemblies, including conformationally defined head-to-tail oligomers. On the other hand, conformationally unrestricted, highly dipolar azo dyes behave as relatively isolated molecules even when present in supersaturated solutions and in close proximity on polymer chains.

Abstract P3-15-05: Muscle and Joint Symptoms in Breast Cancer Patients Receiving Taxane-Based Chemotherapy

Background: Docetaxel, paclitaxel, and (nab)-paclitaxel are taxanes used in treating breast cancer at various stages. While fairly well tolerated, they can cause distressing side effects. Both the prevalence and severity of muscle and joint symptoms (M&JS) in patients receiving taxane-based chemotherapies are poorly documented. We prospectively investigated the prevalence and severity of M&JS in women receiving taxane chemotherapy for breast cancer.

Methods: A total of 275 taxane-naive patients were enrolled in the study. This analysis presents data for 95 patients. For three consecutive treatmentcycles patients completed a baseline questionnaire as well as a diary, days 1 through 7 and on days 14 and 21 following treatment. Patient interviews were done by telephone days 2 to 3, and days 5 to 7 following treatment. They were then contacted at approximately three month intervals for one year. Data collection and data entry are ongoing; long term follow-up will conclude in August 2010.

Results: The average age of patients was 53 years. Disease status was classified as early for 50%, locally advanced for 35.34 %, and metastatic for 15.51% of patients. Overall 41.4% and 39.6% of patients reported muscle and joint pain, respectively, in their diaries on days 1 to 7. Muscle pain was most commonly reported in the legs, back, and arms and joint pain in the knees, ankles, and hips. The pain was most often described as aching, tiring, nagging, exhausting, and tender. The following scores are derived from a 10 cm visual analog scale. Of those who experienced pain in the seven days after treatment, the mean rating for pain at its worst was 5.15 and 5.02 for muscle and joint pain, respectively. Pain at its least had an average rating of 3.42 and 3.41 for muscle and joint pain, respectively. With respect to interference, patients who experienced pain had a mean score of 5.39, 4.86, 5.5, 4.12, 5.36, and 5.44 for interference with basic activities in daily life, mood, working or housework, relationships, sleeping and enjoyment of life, respectively. One, 3, 6, 9 and 12 months after taxane treatment ended, 27.2% (22/81), 31% (13/42), 45.5% (20/44), 37.2% (16/43), and 26.9% (7/26) reported muscle pain, respectively. Joint pain was reported by 26% (21/81), 38.1% (16/42), 43.2% (19/44), 48.8% (21/43) and 34.6% (9/26) of patients 1, 3, 6, 9 and 12 months following treatment, respectively. Data entry and analysis is ongoing and the final analysis will report on pain in relation to the taxane used, steroid tapering, role of anti-hormonal therapy, and effect of menopause on incidence of M&JS.

Discussion: Our preliminary data analysis indicates incidence rates of M&JS higher than previously reported during taxane treatment, and persistence of symptoms in a large proportion of patients up to a year following therapy completion. High pain scores and considerable interference with many aspects of life were reported. This study confirms the significant burden of M&JS during taxane chemotherapy. Conclusions: M&JS during taxane treatment is a common occurrence, and is significantly debilitating to the women who experience it. More research should be done regarding preventative measures and treatment options.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P3-15-05.

A single-nucleotide polymorphism that accounts for allelic variation in the Lr34 gene and leaf rust reaction in hard winter wheat

Leaf rust, caused by Puccinia triticina Eriks, is one of the most common and persistent wheat diseases in the US Great Plains. We report that the Lr34 gene was mapped in the center of a QTL for leaf rust reaction and explained 18-35% of the total phenotypic variation in disease severity of adult plants in a Jagger x 2174 population of recombinant inbred lines (RILs) field-tested for 3 years. The sequence of the complete Lr34 gene was determined for the susceptible Jagger allele and for the resistant 2174 allele. The two alleles had exactly the same sequence as the resistant allele reported previously in Chinese Spring at three polymorphic sites in intron 4, exon 11, and exon 12. A G/T polymorphism was found in exon 22, where a premature stop codon was found in the susceptible Jagger allele (Lr34E22s), confirming a previous report, due to a point mutation compared with the resistant 2174 allele (Lr34E22r). We have experimentally demonstrated a tight association between the point mutation at exon 22 of Lr34 and leaf rust susceptibility in a segregating biparental population. A PCR marker was developed to distinguish between the Lr34E22r and Lr34E22s alleles. A survey of 33 local hard winter wheat cultivars indicated that 7 cultivars carry the Lr34E22s allele and 26 cultivars carry the Lr34E22r allele. This study significantly improves our genetic understanding of allelic variation in the Lr34 gene and provides a functional molecular tool to improve leaf rust resistance in a major US wheat gene pool.

Immunoglobulin superfamily is conserved but evolved rapidly and is active in the silkworm, Bombyx mori

Immunoglobulin superfamily (IgSF) proteins are known for their abilities to specifically recognize and adhere to cells. In this paper, we predicted the presence of 133 IgSF proteins in the silkworm (Bombyx mori) genome. Comparison with similar proteins in other model organisms (Caenorhabditis elegans, Drosophila melanogaster, Anopheles gambiae, Apis mellifera and Homo sapiens) indicated that IgSF proteins are conserved but have rapidly evolved from worms to human beings. However, these proteins are well conserved amongst insects. Silkworm microarray-based expression data showed tissue expression of 57 IgSF genes and microbe-induced differential expression of 37 genes. Based on the expression data, we can conclude that the silkworm IgSF is active.

Molecular identification of a new powdery mildew resistance gene Pm41 on chromosome 3BL derived from wild emmer (Triticum turgidum var. dicoccoides)

Powdery mildew caused by Blumeria graminis f. sp. tritici is an important wheat disease in China and other parts of the world. Wild emmer (Triticum turgidum var. dicoccoides) is the immediate progenitor of cultivated tetraploid and hexaploid wheats and thus an important resource for wheat improvement. Wild emmer accession IW2 collected from Mount Hermon, Israel, is highly resistant to powdery mildew at the seedling and adult plant stages. Genetic analysis using an F(2) segregating population and F(2:3) families, derived from a cross between susceptible durum cultivar Langdon and wild emmer accession IW2, indicated that a single dominant gene was responsible for the resistance of IW2. Bulked segregant and molecular marker analyses detected that six polymorphic SSR, one ISBP, and three EST-STS markers on chromosome 3BL bin 0.63-1.00 were linked to the resistance gene. Allelic variations of resistance-linked EST-STS marker BE489472 revealed that the allele was present only in wild emmer but absent in common wheat. Segregation distortion was observed for the powdery mildew resistance allele and its linked SSR markers with preferential transmission of Langdon alleles over IW2 alleles. The resistance gene was introgressed into common wheat by backcrossing and marker-assisted selection. Since no designated powdery mildew resistance gene has been found on chromosome 3BL, the resistance gene derived from wild emmer accession IW2 appears to be new one and was consequently designated Pm41.

Concentration and detection of SARS coronavirus in sewage from Xiao Tang Shan Hospital and the 309th Hospital of the Chinese People's Liberation Army

A worldwide outbreak of severe acute respiratory syndrome (SARS) had been reported. Over 8439 SARS cases and 812 SARS-related deaths were reported to the World Health Organization from 32 countries around the world up to 5 July 2003. The mechanism of transmission of SARS-CoV has been limited only to close contacts with patients. Attention was focused on possible transmission by the sewage system because laboratory studies showed that patients excreted coronavirus RNA in their stools in Amoy Gardens in Hong Kong. To explore whether the stool of SARS patients or the sewage containing the stool of patients would transmit SARS-CoV or not, we used a style of electropositive filter media particle to concentrate the SARS-CoV from the sewage of two hospitals receiving SARS patients in Beijing, as well as cell culture, semi-nested RT-PCR and sequencing of genes to detect and identify the viruses from sewage. There was no live SARS-CoV detected in the sewage in these assays. The nucleic acid of SARS-CoV was found in the sewage before disinfection from both hospitals by PCR. After disinfection, SARS-CoV RNA could be detected from some samples from the 309th Hospital of the Chinese People's Liberation Army, but not from Xiao Tang Shan Hospital after disinfection. In this study, we found that the virus can survive for 14 days in sewage at 4 degrees C, 2 days at 20 degrees C, and its RNA can be detected for 8 days though the virus had been inactivated. In conclusion, this study demonstrates that the RNA of SARS-CoV could be detected from the concentrates of sewage of both hospitals receiving SARS patients before disinfection and occasionally after disinfection though there was no live SARS-CoV; thus much attention should be paid to the treatment of stools of patients and the sewage of hospitals receiving SARS patients.