Validation of Paraphysomonas diademifera and Polylepidomonas vacuolata (Chrysophyceae)

An account is given on the validation of the combinations Paraphysomonas diademifera (Takahashi) Preisig & Hibberd (basionym: Ochromonas diademifera Taka_ hashi) and Polylepidomonas vacuolata (Thorasen) Preisig & Hibberd (basionym: Paraphysomonas vacuolata Thomsen).     

4-Azolylphenyl isoxazoline insecticides acting at the GABA gated chloride channel

Isoxazoline insecticides have been shown to be potent blockers of insect GABA receptors with excellent activity on a broad pest range, including Lepidoptera and Hemiptera. Herein we report on the synthesis, biological activity and mode-of-action for a class of 4-heterocyclic aryl isoxazoline insecticides.     

A Global Minimization Toolkit for Batch-Fitting and χ2 Cluster Analysis of CW-EPR Spectra

Electron paramagnetic resonance spectroscopy (EPR) is a uniquely powerful technique for characterizing conformational dynamics at specific sites within a broad range of molecular species in water. Computational tools for fitting EPR spectra have enabled dynamics parameters to be determined quantitatively. These tools have dramatically broadened the capabilities of EPR dynamics analysis, however, their implementation can easily lead to overfitting or problems with self-consistency. As a result, dynamics parameters and associated properties become difficult to reliably determine, particularly in the slow-motion regime. Here, we present an EPR analysis strategy and the corresponding computational tool for batch-fitting EPR spectra and cluster analysis of the χ² landscape in Linux. We call this tool CSCA (Chi-Squared Cluster Analysis). The CSCA tool allows us to determine self-consistent rotational diffusion rates and enables calculations of activation energies of diffusion from Arrhenius plots. We demonstrate CSCA using a model system designed for EPR analysis: a self-assembled nanoribbon with radical electron spin labels positioned at known distances off the surface. We anticipate that the CSCA tool will increase the reproducibility of EPR fitting for the characterization of dynamics in biomolecules and soft matter.     

Inter-Slice Blood Flow and Magnetization Transfer Effects as A New Simultaneous Imaging Strategy

The recent blood flow and magnetization transfer (MT) technique termed alternate ascending/descending directional navigation (ALADDIN) achieves the contrast using interslice blood flow and MT effects with no separate preparation RF pulse, thereby potentially overcoming limitations of conventional methods. In this study, we examined the signal characteristics of ALADDIN as a simultaneous blood flow and MT imaging strategy, by comparing it with pseudo-continuous ASL (pCASL) and conventional MT asymmetry (MTA) methods, all of which had the same bSSFP readout. Bloch-equation simulations and experiments showed ALADDIN perfusion signals increased with flip angle, whereas MTA signals peaked at flip angle around 45°−60°. ALADDIN provided signals comparable to those of pCASL and conventional MTA methods emulating the first, second, and third prior slices of ALADDIN under the same scan conditions, suggesting ALADDIN signals to be superposition of signals from multiple labeling planes. The quantitative cerebral blood flow signals from a modified continuous ASL model overestimated the perfusion signals compared to those measured with a pulsed ASL method. Simultaneous mapping of blood flow, MTA, and MT ratio in the whole brain is feasible with ALADDIN within a clinically reasonable time, which can potentially help diagnosis of various diseases.     

Investigation of Inter-Slice Magnetization Transfer Effects as a New Method for MTR Imaging of the Human Brain

We present a new method for magnetization transfer (MT) ratio imaging in the brain that requires no separate saturation pulse. Interslice MT effects that are inherent to multi-slice balanced steady-state free precession (bSSFP) imaging were controlled via an interslice delay time to generate MT-weighted (0 s delay) and reference images (5–8 s delay) for MT ratio (MTR) imaging of the brain. The effects of varying flip angle and phase encoding (PE) order were investigated experimentally in normal, healthy subjects. Values of up to ∼50% and ∼40% were observed for white and gray matter MTR. Centric PE showed larger MTR, higher SNR, and better contrast between white and gray matter than linear PE. Simulations of a two-pool model of MT agreed well with in vivo MTR values. Simulations were also used to investigate the effects of varying acquisition parameters, and the effects of varying flip angle, PE steps, and interslice delay are discussed. Lastly, we demonstrated reduced banding with a non-balanced SSFP-FID sequence and showed preliminary results of interslice MTR imaging of meningioma.     

Can source–sink relations explain responses of tobacco to infection by the root holoparasitic angiosperm Orobanche cernua?

The achlorophyllous holoparasitic angiosperm Orobanche cernua reduced biomass accumulation of its tobacco host, such that 73-d-old plants achieved 29% of the biomass of control plants. The difference in biomass between infected and uninfected tobacco could be accounted for directly by diversion of dry matter to the parasite. Thus, the smaller infected plants were responsible for the production of as much dry matter in host and parasite as their larger uninfected counterparts. The productivity of the infected system was maintained by: (a) sustained production of leaf area (a greater leaf area ratio); (b) increased specific leaf area, and (c) delayed senescence. When tobacco was inoculated with different densities of the parasite, the amount of dry matter accumulated by the parasite was not changed, suggesting that a finite amount of resource was available to the parasite. The response of the host to infection can be explained by simple source–sink interactions and the data are discussed with respect to other parasitic angiosperm–host systems which show different types of responses.     

Mannose-containing oligosaccharides of non-specific human secretory immunoglobulin A mediate inhibition of Vibrio cholerae biofilm formation

The role of antigen-specific secretory IgA (SIgA) has been studied extensively, whereas there is a limited body of evidence regarding the contribution of non-specific SIgA to innate immune defenses against invading pathogens. In this study, we evaluated the effects of non-specific SIgA against infection with Vibrio cholerae O139 strain MO10 and biofilm formation. Seven day old infant mice deficient in IgA (IgA(-/-) mice) displayed significantly greater intestinal MO10 burden at 24 hr post-challenge when compared to IgA(+/+) pups. Importantly, cross-fostering of IgA(-/-) pups with IgA(+/+) nursing dams reversed the greater susceptibility to MO10 infection, suggesting a role for non-specific SIgA in protection against the infection. Since biofilm formation is associated with virulence of MO10, we further examined the role of human non-specific SIgA on this virulence phenotype of the pathogen. Human non-specific SIgA, in a dose-dependent fashion, significantly reduced the biofilm formation by MO10 without affecting the viability of the bacterium. Such an inhibitory effect was not induced by human serum IgA, IgG, or IgM, suggesting a role for the oligosaccharide-rich secretory component (SC) of SIgA. This was supported by the demonstration that SIgA treated with endoglycosidase H, to cleave the high-mannose containing terminal chitobiose residues, did not induce a reduction in biofilm formation by MO10. Furthermore, the addition of free mannose per se, across a wide dose range, induced significant reduction in MO10 biofilm formation. Collectively, these results suggest that mannose containing oligosaccharides within human non-specific secretory IgA can alter important virulence phenotypes of Vibrio cholerae such as biofilm formation, without affecting viability of the microorganism. Such effects may contribute significantly to innate immune defenses against invading pathogens in vivo in the gastrointestinal tract.     

Does Smoke from Biomass Fuel Contribute to Anemia in Pregnant Women in Nagpur,India? A Cross-Sectional Study

BackgroundAnemia affects upwards of 50% of pregnant women in developing countries and is associated with adverse outcomes for mother and child. We hypothesized that exposure to smoke from biomass fuel – which is widely used for household energy needs in resource-limited settings – could exacerbate anemia in pregnancy, possibly as a result of systemic inflammation.ObjectiveTo evaluate whether exposure to smoke from biomass fuel (wood, straw, crop residues, or dung) as opposed to clean fuel (electricity, liquefied petroleum gas, natural gas, or biogas) is an independent risk factor for anemia in pregnancy, classified by severity.MethodsA secondary analysis was performed using data collected from a rural pregnancy cohort (N = 12,782) in Nagpur, India in 2011-2013 as part of the NIH-funded Maternal and Newborn Health Registry Study. Multinomial logistic regression was used to estimate the effect of biomass fuel vs. clean fuel use on anemia in pregnancy, controlling for maternal age, body mass index, education level, exposure to household tobacco smoke, parity, trimester when hemoglobin was measured, and receipt of prenatal iron and folate supplements.ResultsThe prevalence of any anemia (hemoglobin < 11 g/dl) was 93% in biomass fuel users and 88% in clean fuel users. Moderate-to-severe anemia (hemoglobin < 10 g/dl) occurred in 53% and 40% of the women, respectively. Multinomial logistic regression showed higher relative risks of mild anemia in pregnancy (hemoglobin 10-11 g/dl; RRR = 1.38, 95% CI = 1.19-1.61) and of moderate-to-severe anemia in pregnancy (RRR = 1.79, 95% CI = 1.53-2.09) in biomass fuel vs. clean fuel users, after adjusting for covariates.ConclusionIn our study population, exposure to biomass smoke was associated with higher risks of mild and moderate-to-severe anemia in pregnancy, independent of covariates.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT 01073475","term_id":"NCT01073475"}}NCT 01073475     

Strategies for engineering a two-celled C(4) photosynthetic pathway into rice

Every day almost one billion people suffer from chronic hunger, and the situation is expected to deteriorate with a projected population growth to 9 billion worldwide by 2050. In order to provide adequate nutrition into the future, rice yields in Asia need to increase by 60%, a change that may be achieved by introduction of the C(4) photosynthetic cycle into rice. The international C(4) Rice Consortium was founded in order to test the feasibility of installing the C(4) engine into rice. This review provides an update on two of the many approaches employed by the C(4) Rice Consortium: namely, metabolic C(4) engineering and identification of determinants of leaf anatomy by mutant screens. The aim of the metabolic C(4) engineering approach is to generate a two-celled C(4) shuttle in rice by expressing the classical enzymes of the NADP-ME C(4) cycle in a cell-appropriate manner. The aim is also to restrict RuBisCO and glycine decarboxylase expression to the bundle sheath (BS) cells of rice in a C(4)-like fashion by specifically down-regulating their expression in rice mesophyll (M) cells. In addition to the changes in biochemistry, two-celled C(4) species show a convergence in leaf anatomy that include increased vein density and reduced numbers of M cells between veins. By screening rice activation-tagged lines and loss-of-function sorghum mutants we endeavour to identify genes controlling these key traits.