Measuring T₂ and T₁, and imaging T₂ without spin echoes

During adiabatic excitation, the nuclear magnetization in the transverse plane is subject to T(2) (spin-spin) relaxation, depending on the pulse length τ. Here, this property is exploited in a method of measuring T(2) using the ratio of NMR signals acquired with short and long-duration self-refocusing adiabatic pulses, without spin-echoes. This Dual-τ method is implemented with B(1)-insensitive rotation (BIR-4) pulses. It is validated theoretically with Bloch equation simulations independent of flip-angle, and experimentally in phantoms. Dual-τT(2) measurements are most accurate at short T(2) where results agree with standard spin-echo measures to within 10% for T(2) ≤ 100 ms. Dual-τ MRI performed with a long 0° BIR-4 pre-pulse provides quantitative T(2) imaging of phantoms and the human foot while preserving desired contrast and functional properties of the rest of the MRI sequence. A single 0° BIR-4 pre-pulse can provide T(2) contrast-weighted MRI and serve as a "T(2)-prep" sequence with a lower B(1) requirement than prior approaches. Finally, a Tri-τ experiment is introduced in which both τ and flip-angle are varied, enabling measurement of T(2), T(1) and signal intensity in just three acquisitions if flip-angles are well-characterized. These new methods can potentially save time and simplify relaxation measurements and/or contrast-weighted NMR and MRI.

Effectiveness of applying arsenate reducing bacteria to enhance arsenic removal from polluted soils by Pteris vittata L

Arsenic is a common contaminant in soils and water. It is well established that the fern Pteris vittata L. is an As hyperaccumulator and therefore has potential to phyroremediate As-polluted soils. Also, it is accepted that rhizosphere microflora play an enhancing role in plant uptake of metallic elements from soils. Studies showed that hydroponiclly grown P. Vittata accumulated arsenite more than the arsenate form of As apparently because arsenate and phosphate are analogues and therefore its absorption is inhibited by phosphate. The objective of this study was to determine whether addition of five different arsenate-reducing bacteria would enhance arsenic uptake by P. vittata grown in arsenic polluted soils in afield experiment. Results showed that addition of the As reducing bacteria promoted the growth of P. vittata, increased As accumulation, activated soil insoluble As, and reduced As leaching compared to the untreated control. Plant biomass increased by 53% and As uptake by 44%. As leaching was reduced by 29% to 71% depending on the As reducing bacterium. The results in their entirety permitted some insight into the mechanisms by which the arsenate reducing bacteria enhanced the effectiveness of P. vittata to remove As from the polluted soil.

Functional analysis of the kinome of the wheat scab fungus Fusarium graminearum

As in other eukaryotes, protein kinases play major regulatory roles in filamentous fungi. Although the genomes of many plant pathogenic fungi have been sequenced, systematic characterization of their kinomes has not been reported. The wheat scab fungus Fusarium graminearum has 116 protein kinases (PK) genes. Although twenty of them appeared to be essential, we generated deletion mutants for the other 96 PK genes, including 12 orthologs of essential genes in yeast. All of the PK mutants were assayed for changes in 17 phenotypes, including growth, conidiation, pathogenesis, stress responses, and sexual reproduction. Overall, deletion of 64 PK genes resulted in at least one of the phenotypes examined, including three mutants blocked in conidiation and five mutants with increased tolerance to hyperosmotic stress. In total, 42 PK mutants were significantly reduced in virulence or non-pathogenic, including mutants deleted of key components of the cAMP signaling and three MAPK pathways. A number of these PK genes, including Fg03146 and Fg04770 that are unique to filamentous fungi, are dispensable for hyphal growth and likely encode novel fungal virulence factors. Ascospores play a critical role in the initiation of wheat scab. Twenty-six PK mutants were blocked in perithecia formation or aborted in ascosporogenesis. Additional 19 mutants were defective in ascospore release or morphology. Interestingly, F. graminearum contains two aurora kinase genes with distinct functions, which has not been reported in fungi. In addition, we used the interlog approach to predict the PK-PK and PK-protein interaction networks of F. graminearum. Several predicted interactions were verified with yeast two-hybrid or co-immunoprecipitation assays. To our knowledge, this is the first functional characterization of the kinome in plant pathogenic fungi. Protein kinase genes important for various aspects of growth, developmental, and infection processes in F. graminearum were identified in this study.

Fusarium head blight caused by Fusarium graminearum is one of the most important diseases on wheat and barley. Although protein kinases are known to play major regulatory roles in fungi, systematic characterization of fungal kinomes has not been reported in plant pathogens. In this study we generated deletion mutants for 96 protein kinase genes. All of the resulting knockout mutants were assayed for changes in 17 phenotypes, including growth, reproduction, stress responses, and plant infection. Overall, deletion of 64 kinase genes resulted in at least one of the phenotypes examined. In total, 42 kinase mutants were significantly reduced in virulence or non-pathogenic. A number of these protein kinase genes, including two that are unique to filamentous fungi, are dispensable for hyphal growth and likely encode novel fungal virulence factors. Ascospores are the primary inoculum for wheat scab. We identified 26 mutants blocked in ascospore. We also used the in silico approach to predict the kinase-kinase interactions and verified some of them by yeast two-hybrid or co-IP assays. Overall, in this study we functionally characterize the kinome of F. graminearum. Protein kinase genes that are important for various aspects of growth, developmental, and plant infection processes were identified.

Abstract P270: Resin-Assisted Capture Reveals Unique Targets of Oxidation in Ischemic Preconditioning

Proper maintenance of cellular thiol redox status is critical in the regulation of many processes that dictate normal myocardial function. Cell death signaling, in particular, is especially susceptible to alterations in thiol redox state. Myocardial ischemic preconditioning (IPC) is a redox sensitive process that is thought to provide protection from ischemia-reperfusion (IR) injury, in part, via reversible oxidative signaling. Protein S -nitrosylation (SNO) is a reversible, thiol-based modification that we and others have shown to provide cardioprotection by modulating the activity of target proteins and by shielding cysteine residues from irreversible oxidation. Additional thiol-based modifications are also thought to play an important role in cardioprotection, and these include disulfide bridges and glutathiolation. Therefore, it is of interest to identify these redox sensitive targets that are unique to IPC. Langendorff perfused mouse hearts were subjected to various perfusion protocols (control, IPC, IR, IPC-IR) and homogenized. Specific sites of oxidation were identified using oxidation-resin assisted capture (Ox-RAC) with mass spectrometry. Consistent with a role for oxidative signaling in cardioprotection, Ox-RAC analysis identified 56 proteins that were oxidized with IPC, but not IR or IPC-IR. These proteins are likely to be reversibly oxidized, as evidenced by the fact that they are oxidized with IPC, but are no longer oxidized following reperfusion (IPC-IR). These proteins may represent important targets in cardioprotective signaling and include F-actin-capping protein β, Egl nine homolog 1, and numerous members of the heat shock family (HSP60, HSP70, HSP90β). Heat shock proteins are important in the cellular stress response and have been shown to play an important role in cardioprotection. Pathway analysis also revealed that more than 30% (19 of 56) of the proteins uniquely oxidized following IPC were involved with cell death pathways. These proteins include Aminoacyl tRNA synthase complex-interacting multifunctional protein 1, Charged multivesicular body protein 5, and Lamin-A/C. These results indicate that the cardioprotective effects of IPC may occur, in part, through the reversible oxidation of key protein targets.

Cognitive impairment using education-based cutoff points for CMMSE scores in elderly Chinese people of agricultural and rural Shanghai China

OBJECTIVES

To evaluate cognitive impairment (CI) in rural China using the Chinese version of the Mini-Mental Status Examination (CMMSE) and compare the prevalence of CI using two different cutoff points.

MATERIALS & METHODS

A population-based survey was conducted of 2809 people aged 60 years and above in a community of two towns (Huaxin and Xujing) in the Qingpu district, located in the western suburb of Shanghai. Face-to-face interviews were carried out to collect relevant information with questionnaires. The Chinese version of the Mini-Mental State Examination with either a 23/24 cutoff point or a cutoff point varying according to education level (AEL) was used to screen subjects for CI.

RESULTS

Among these subjects, the mean age was 70.6 years (SD = 6.6) and ranged from 60 to 92 years and included 1010 (36.0%) men and 1799 (64.0%) women. The mean age was 70.7 years (SD = 6.4) for men and 70.5 years (SD = 6.7) for women. Of the 2809 subjects, 2010 (71.5%) had no formal education, 607 (21.6%) completed 1-6 years of education, and 173 (6.2%) completed more than 6 years of school education. The prevalence of CI was 35.6% (95% CI: 33.8-37.4) for both genders when the cutoff point of 23/24 was used. However, when the cutoff point was altered with respect to different education levels, the prevalence of CI was 7.0%. For each item of the CMMSE, increased years of education correlated with a higher item score, with the exception of the 'Naming' item score.

CONCLUSIONS

This study demonstrates that screening of CI using the AEL cutoff scores is feasible in a low-education population. Determining whether the 23/24 cutoff point is suitable for the Chinese people requires future prospective studies in a large Chinese population.

Bacterial communities in sediments of the shallow Lake Dongping in China

AIMS

The purpose of this study was to discuss how the environmental inputs and anthropogenic activities impact bacterial communities in the sediments of a shallow, eutrophic and temperate freshwater lake.

METHODS AND RESULTS

Sediment cores were collected from Lake Dongping, located in Taian, Shandong, China. All samples were processed within 4 h of collection. Total nitrogen, total phosphorus (TP), total organic carbon, ammonium nitrogen and nitrate nitrogen content of samples were measured by Kjeldahl determination, sulphuric acid-perchloric acid digestion and molybdenum blue colorimetry, potassium dichromate titration, Nessler's reagent colorimetric and the phenol disulphonic acid colorimetric method, respectively. Seasonal and temporal diversity of sediment bacterial communities at six stations in Lake Dongping were investigated using molecular approaches (terminal restriction fragment length polymorphism and 16S rDNA clone libraries). Noticeable seasonal and temporal variations were observed in bacterial diversity and composition at all six stations. Sediment bacterial communities in Lake Dongping belonged to 16 phyla: Proteobacteria (including α-Proteobacteria, β-Proteobacteria, δ-Proteobacteria, ε-Proteobacteria, γ-Proteobacteria), Acidobacteria, Planctomycetes, Bacteroidetes, Firmicutes, Verrucomicrobia, Nitrospira, Chloroflexi, Gemmatimonadetes, Chlorobi, Cyanobacteria, Deferribacteres, Actinobacteria, OP8, Spirochaetes and OP11. Members of β-, δ- and γ-Proteobacterial sequences were predominant in 11 of 12 clone libraries derived from sediment samples. Sediment samples collected at stations 1 and 4 in July had the greatest bacterial diversity while those collected at station 2 in October had the least diversity. TP concentration was significantly correlated with the distribution of bacterial communities.

CONCLUSIONS

Our results suggested that different environmental nutrient inputs contribute to seasonal and temporal variations of chemical features and bacterial communities in sediments of Lake Dongping. TP concentration was significantly correlated with the distribution of bacterial communities.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study has an important implication for the optimization of integrated ecosystem assessment of shallow temperate freshwater lake and provides interesting information for the subsequent of the ecosystem.

3 T MRI of hepatocellular carcinomas in patients with cirrhosis: does T2-weighted imaging provide added value?

AIM

To assess whether T2-weighted imaging (T2WI) provides any added value for the detection of hepatocellular carcinoma (HCC) in patients with cirrhosis, especially for lesions smaller than 2 cm.

MATERIALS AND METHODS

Sixty-five patients with cirrhosis underwent liver 3 T MRI. Images were qualitatively analysed independently by two observers in two separate sessions, including a dynamic enhanced session and a combination of dynamic and T2WI. The diagnostic accuracy was evaluated using the alternating free-response receiver operating characteristic. Sensitivity and positive predictive values were calculated for all HCCs and for the subgroup of HCCs that were smaller than 2 cm. Additionally, artefacts on T2WI were evaluated by two observers in consensus.

RESULTS

Ninety HCCs (>2 cm n = 36; ≤2 cm n = 54) were detected in 46 patients. For all HCCs and for lesions smaller than 2 cm, the sensitivities were significantly higher for the combined session than the dynamic session alone (p < 0.05). Conversely, for the Az and positive predictive values, there was no significant difference between the two sessions. For smaller HCC, 9% (5/54) and 7% (4/54) of the 54 HCCs were correctly interpreted by observers 1 and 2, respectively, only when T2WI was included. Three false-positive lesions (≤2 cm) were correctly diagnosed by one of the observers after combining T2WI. Conspicuity of only one large HCC was severely reduced by the artefacts from massive ascites.

CONCLUSION

At 3 T liver imaging, combining with T2WI can improve the sensitivity of detection of HCC compared with dynamic MRI alone by increasing observer confidence, especially for lesions smaller than 2 cm. Additionally, T2 image quality was not significantly affected by artefacts.

Enhanced antitumor activity of epirubicin combined with cerulenin in osteosarcoma

Osteosarcoma (OS) is the most common primary malignant neoplasm in children and adolescents. Epirubicin is one of the chemotherapeutic agents currently used for the treatment of OS; however, the efficacy of chemotherapy is hampered by the acquired drug resistance of OS. Cerulenin, an inhibitor of fatty acid synthase, has been defined as a candidate tumor suppressor. In this study, we explored the combined effect of cerulenin plus the chemotherapy drug, epirubicin, on human OS U2-OS cells in vitro and in vivo. We demonstrated that cerulenin plus epirubicin induced synergistic growth inhibition and enhanced apoptosis in U2-OS cells. We also demonstrated that cerulenin plus epirubicin synergistically suppressed tumor growth in subcutaneously xenografted U2-OS cells in athymic nude mice. Our results indicate that cerulenin enhances the anti-OS effects of epirubicin in vivo and in vitro.

Gene-vitamin D interactions on food sensitization: a prospective birth cohort study

BACKGROUND

It has been hypothesized that vitamin D deficiency (VDD) contributes to the development of food sensitization (FS) and then food allergy. However, the epidemiological evidence is conflicting. We aim to examine whether cord blood VDD is associated with FS and whether such association can be modified by genetic variants in a prospective birth cohort.

METHODS

This study included 649 children who were enrolled at birth and followed from birth onward at the Boston Medical Center. We defined VDD as cord blood 25(OH)D < 11 ng/ml, and FS as specific IgE ≥ 0.35 kUA/l to any of eight common food allergens in early childhood. We genotyped potentially functional single-nucleotide polymorphisms (SNPs) in 11 genes known to be involved in regulating IgE and 25(OH)D concentrations. Logistic regressions were used to test the effects of VDD on FS individually and jointly with SNPs.

RESULTS

Among the 649 children, 44% had VDD and 37% had FS. When examined alone, VDD was not associated with FS. When examined jointly with SNPs, a significant interaction between IL4 gene polymorphism (rs2243250) and VDD (p(interaction) = 0.003, p(FDR) = 0.10) was found: VDD increased the risk of FS among children carrying CC/CT genotypes (OR = 1.79, 95%CI: 1.15-2.77). Similar but weaker interactions were observed for SNPs in MS4A2 (rs512555), FCER1G (rs2070901), and CYP24A1 (rs2762934). When all four SNPs were simultaneously considered, a strong gene-VDD interaction was evident (p(interaction) = 9 × 10(-6) ).

CONCLUSIONS

Our data demonstrate that VDD may increase the risk of FS among individuals with certain genotypes, providing evidence of gene-vitamin D interaction on FS.

Oxidized DJ-1 interacts with the mitochondrial protein BCL-XL

Parkinson disease (PD)- and cancer-associated protein, DJ-1, mediates cellular protection via many signaling pathways. Deletions or mutations in the DJ-1 gene are directly linked to autosomal recessive early-onset PD. DJ-1 has potential roles in mitochondria. Here, we show that DJ-1 increases its mitochondrial distribution in response to ultraviolet B (UVB) irradiation and binds to Bcl-X(L). The interactions between DJ-1 and Bcl-X(L) are oxidation-dependent. DJ-1(C106A), a mutant form of DJ-1 that is unable to be oxidized, binds Bcl-X(L) much less than DJ-1 does. Moreover, DJ-1 stabilizes Bcl-X(L) protein level by inhibiting its ubiquitination and degradation through ubiquitin proteasome system (UPS) in response to UVB irradiation. Furthermore, under UVB irradiation, knockdown of DJ-1 leads to increases of Bcl-X(L) ubiquitination and degradation upon UVB irradiation, thereby increasing mitochondrial Bax, caspase-3 activation and PARP cleavage. These data suggest that DJ-1 protects cells against UVB-induced cell death dependent on its oxidation and its association with mitochondrial Bcl-X(L).

Identification of proteins and phosphoproteins using pulsed Q collision induced dissociation (PQD)

Pulsed Q collision induced dissociation (PQD) was developed to facilitate detection of low-mass reporter ions from labeling reagents (e.g., iTRΑQ) in peptide quantification using an LTQ mass spectrometer (MS). Despite the large number of linear ion traps worldwide, the use and optimization of PQD for protein identification have been limited, in part due to less effective ion fragmentation relative to the collision induced dissociation (CID). PQD expands the m/z coverage of fragment ions to the lower m/z range by circumventing the typical low mass cut-off of an ion trap MS. Since database searching relies on the matching between theoretical and observed spectra, it is not clear how ion intensity and peak number might affect the outcomes of a database search. In this report, we systematically evaluated the attributes of PQD mass spectra, performed intensity optimization, and assessed the benefits of using PQD on the identification of peptides and phosphopeptides from an LTQ. Based on head-to-head comparisons between CID (higher intensity) and PQD (better m/z coverage), peptides identified using PQD generally have Xcorr scores lower than those using CID. Such score differences were considerably diminished by the use of 0.1% m-nitrobenzyl alcohol (m-NBA) in mobile phases. The ion intensities of both CID and PQD were adversely affected by increasing m/z of the precursor, with PQD more sensitive than CID. In addition to negating the 1/3 rule, PQD enhances direct bond cleavage and generates patterns of fragment ions different from those of CID, particularly for peptides with a labile functional group (e.g., phosphopeptides). The higher energy fragmentation pathway of PQD on peptide fragmentation was further compared to those of CID and the quadrupole-type activation in parallel experiments.

Effect of genistein on the activities of cytochrome P450 3A and P-glycoprotein in Chinese healthy participants

To determine the effect of genistein on cytochrome P450 3A (CYP3A) and P-glycoprotein (P-gp) function using the probe substrates midazolam and talinolol, respectively. Eighteen healthy adult male participants were enrolled in a two-phase randomized crossover design. In each phase, the participants received placebo or genistein for 14 days. On the 15th day, midazolam and talinolol were administered and blood samples were obtained. Midazolam and talinolol pharmacokinetic parameter values were calculated and compared before and after genistein administration. Co-administration of genistein decreased the area under the concentration-time curve from 0 to 36 h (AUC 0-36) (143.65 ± 55.40 ng h/mL versus 126.10 ± 40.14 ng h/mL, p < 0.05), and the area under the concentration-time curve from zero to infinity (AUC 0-∞) (209.18 ± 56.61 ng h/mL versus 180.59 ± 43.03 ng h/mL, p < 0.05), and also maximum concentration (Cmax) of midazolam (48.86 ± 20.21 ng/mL versus 36.25 ± 14.35 ng/mL p < 0.05). Similarly, AUC 0-36 (2490.282 ± 668.79 ng h/mL versus 2114.46 ± 861.11 ng h/mL, p < 0.05), AUC 0-∞ (2980.45 ± 921.09 ng h/mL versus 2626.92 ± 1003.78 ng h/mL, p < 0.05) and Cmax of talinolol (326.58 ± 197.67 ng/mL versus 293.42 ± 127.19 ng/mL, p < 0.05) were reduced by genistein co-administration. The oral clearance of midazolam (1.68 ± 0.85 h-1 versus 3.98 ± 0.59 h-1, p < 0.05) and talinolol (3.34 ± 1.24 h-1 versus 3.79 ± 1.55 h-1, p<0.05) were increased by genistien significantly. Administration of genistein can result in a modest induction of CYP3A and possibly P-gp activity in healthy volunteers.