Isolation of a heat-stable maize endosperm ADP-glucose pyrophosphorylase variant

Heat stress reduces maize yield and several lines of evidence suggest that the heat lability of maize endosperm ADP-glucose pyrophosphorylase (AGPase) contributes to this yield loss. AGPase catalyzes a rate-limiting step in starch synthesis. Herein, we present a novel maize endosperm AGPase small subunit variant, termed BT2-TI that harbors a single amino acid change of residue 462 from threonine to isoleucine. The mutant was isolated by random mutagenesis and heterologous expression in a bacterial system. BT2-TI exhibits enhanced heat stability compared to wildtype maize endosperm AGPase.The TI mutation was placed into another heat-stable small subunit variant, MP. MP is composed of sequences from the maize endosperm and the potato tuber small subunit. The MP-TI small subunit variant exhibited greater heat stability than did MP. Characterization of heat stability as well as kinetic and allosteric properties suggests that MP-TI may lead to increased starch yield when expressed in monocot endosperms.     

Lipids of Pinus halepensis pollen

The total lipids of Pinus halepensis pollen were separated into individual classes of neutral and polar lipids and the components of each class were identified and determined quantitatively. Free fatty acids, waxes and triacylglycerols were found as the main constituents of neutral lipids and phosphatidylcholine and phosphatidylethanolamine of polar lipids. Glycerylether derivatives were detected in neutral and polar lipid fractions. Free and esterified volatile fatty acids were also found in pollen and its neutral lipid fraction.     

Reversible cytoplasmic rearrangements precede wall apposition,hypersensitive cell death and defense-related gene activation in potato/Phytophthora infestans interactions

We used video microscopy techniques as a tool for live examination of the dynamic aspects of plant/fungus interactions. Early, dynamic responses of epidermal midrib cells of leaves from a potato cultivar (Solanum tuberosum L. cv. Datura) carrying resistance gene R1 to Phytophthora infestans (race 1: compatible interaction, race 4: incompatible interaction) were monitored. Similar responses were observed in both types of interaction, ranging from no visible reaction of invaded plant cells to hypersensitive cell death. The overall defense response of each individual cell exhibited a highly dynamic behavior that appeared to be tightly coordinated with the growth of the fungus. Initial localized reactions, including major rearrangements within the cytoplasm, occurred directly at the fungal penetration site, where rapid apposition of autofluorescent material and callose took place. If fungal invasion stopped at this stage, the host cell restored its normal cytoplasmic activity and survived. Hypersensitive cell death occurred only when fungal growth had proceeded to the formation of a clearly identifiable haustorium. In such cases, cytoplasm and nucleus conglomerated around the intracellular fungal structure, followed by a sudden collapse of the whole conglomerate and an instantaneous collapse of the fungal haustorium. Only small quantitative differences between the compatible and incompatible interactions of the two fungal races were observed for these early responses of epidermal cells. In the incompatible interaction, a slightly larger number of epidermal cells responded to fungal attack. More pronounced quantitative differences between compatible and incompatible interactions occurred upon fungal invasion of the mesophyll. These differences in the number of responding cells were not reflected at the level of gene expression: the spatial and temporal activation patterns of two defense-related genes, encoding phenylalanine ammonia-lyase and pathogenesis-related protein 1, were similar in both types of interaction.Dedicated to Professor Peter Sitte, Freiburg, Germany, on the occasion of his 65th birthday     

Description of a new species,Globotruncana pseudoconica and remarks on its relation to Globotruncana conicaWhite and Globotruncana falsostuartiSigal

A new, strongly spiroconvex Globotruncana species,Globotruncana pseudoconica nov. sp., is described from the Maastrichtian of Tunisia. It is distinguished from Globotruncana conicaWhite in morphology and phylogeny. Some Maastrichtian, strongly spiroconvex specimens referred to as Globotruncana conicaWhite, are shown to be identical to Globotruncana pseudoconica nov. sp. The new species reveals close affinity with Globotruncana falsostuartiSigal from which it has evolved during the middle Lower Maastrichtian.     

Effect in neonatal thymectomy on experimental autoimmune thyroiditis in guinea pigs.

These studies examined the effect of neonatal thymectomy on the induction of experimental autoimmune thyroiditis (EAT) in the guinea pigs. Thymectomy was found to result in a consistent and profound inhibition of the development of lesions of EAT in both strain 2 and strain 13 guinea pigs. Thymectomized guinea pigs also had reduced antibody titers to guinea pig thyroglobulin (GPTG), while delayed hypersensitivity reactions to GPTG were less markedly affected by thymectomy. Thymectomized guinea pigs had significant functional peripheral T cells as evidenced by normal responses of lymph node cells to T cell mitogens. These results indicate that a T cell subpopulation which is sensitive to neonatal thymectomy is required for the development of EAT and antithyroglobulin antibody in the guinea pig.     

Thiol redox state and related enzymes in sclerotium-forming filamentous phytopathogenic fungi

Thiol redox state (TRS) reduced and oxidized components form profiles characteristic of each of the four main types of differentiation in the sclerotiogenic phytopathogenic fungi: loose, terminal, lateral-chained, and lateral-simple, represented by Rhizoctonia solani, Sclerotinia sclerotiorum, Sclerotium rolfsii, and Sclerotinia minor, respectively. A common feature of these fungi is that as their undifferentiated mycelium enters the differentiated state, it is accompanied by a decrease in the low oxidative stress-associated total reduced thiols and/or by an increase of the high oxidative stress-associated total oxidized thiols either in the sclerotial mycelial substrate or in its corresponding sclerotium, indicating a relationship between TRS-related oxidative stress and sclerotial differentiation. Moreover, the four studied sclerotium types exhibit high activities of TRS-related antioxidant enzymes, indicating the existence of antioxidant protection of the hyphae of the sclerotium medulla until conditions become appropriate for sclerotium germination.     

Minibrain-related kinase/dual-specificity tyrosine-regulated kinase 1B implication in stem/cancer stem cells biology

Dual-specificity tyrosine phosphorylation-regulated kinase 1B (DYRK1B), also known as minibrain-related kinase (MIRK) is one of the best functionally studied members of the DYRK kinase family. DYRKs comprise a family of protein kinases that are emerging modulators of signal transduction pathways, cell proliferation and differentiation, survival, and cell motility. DYRKs were found to participate in several signaling pathways critical for development and cell homeostasis. In this review, we focus on the DYRK1B protein kinase from a functional point of view concerning the signaling pathways through which DYRK1B exerts its cell type-dependent function in a positive or negative manner, in development and human diseases. In particular, we focus on the physiological role of DYRK1B in behavior of stem cells in myogenesis, adipogenesis, spermatogenesis and neurogenesis, as well as in its pathological implication in cancer and metabolic syndrome. Thus, understanding of the molecular mechanisms that regulate signaling pathways is of high importance. Recent studies have identified a close regulatory connection between DYRK1B and the hedgehog (HH) signaling pathway. Here, we aim to bring together what is known about the functional integration and cross-talk between DYRK1B and several signaling pathways, such as HH, RAS and PI3K/mTOR/AKT, as well as how this might affect cellular and molecular processes in development, physiology, and pathology. Thus, this review summarizes the major known functions of DYRK1B kinase, as well as the mechanisms by which DYRK1B exerts its functions in development and human diseases focusing on the homeostasis of stem and cancer stem cells.     

The effect of the elongation of the proximal aorta on the estimation of the aortic wall distensibility

The compliance of the proximal aortic wall is a major determinant of cardiac afterload. Aortic compliance is often estimated based on cross-sectional area changes over the pulse pressure, under the assumption of a negligible longitudinal stretch during the pulse. However, the proximal aorta is subjected to significant axial stretch during cardiac contraction. In the present study, we sought to evaluate the importance of axial stretch on compliance estimation by undertaking both an in silico and an in vivo approach. In the computational analysis, we developed a 3-D finite element model of the proximal aorta and investigated the discrepancy between the actual wall compliance to the value estimated after neglecting the longitudinal stretch of the aorta. A parameter sensitivity analysis was further conducted to show how increased material stiffness and increased aortic root motion might amplify the estimation errors (discrepancies between actual and estimated distensibility ranging from − 20 to − 62%). Axial and circumferential aortic deformation during ventricular contraction was also evaluated in vivo based on MR images of the aorta of 3 healthy young volunteers. The in vivo results were in good qualitative agreement with the computational analysis (underestimation errors ranging from − 26 to − 44%, with increased errors reflecting higher aortic root displacement). Both the in silico and in vivo findings suggest that neglecting the longitudinal strain during contraction might lead to severe underestimation of local aortic compliance, particularly in the case of women who tend to have higher aortic root motion or in subjects with stiff aortas.

     

Stereocontrolled Facile Synthesis and Biological Evaluation of (3′S) and (3′R)-3′-Amino (and Azido)-3′-Deoxy Pyranonucleosides

This article describes the synthesis of (3 ′S) and (3 ′R)-3 ′-amino-3 ′-deoxy pyranonucleosides and their precursors (3 ′S) and (3 ′R)-3 ′-azido-3 ′-deoxy pyranonucleosides. Azidation of 1,2:5,6-di-O-isopropylidene-3-O-toluenesulfonyl-α-D-allofuranose followed by hydrolysis and subsequent acetylation afforded 3-azido-3-deoxy-1,2,4,6-tetra-O-acetyl-D-glucopyranose, which upon coupling with the proper silylated bases, deacetylation, and catalytic hydrogenation, obtained the target 3 ′-amino-3 ′-deoxy-β-D-glucopyranonucleosides. The desired 1-(3 ′-amino-3 ′-deoxy-β-D-allopyranosyl)5-fluorouracil was readily prepared from the suitable imidazylate sugar after azidation followed by a protection/deprotection sequence and reduction of the unprotected azido precursor. No antiviral activity was observed for the novel nucleosides. Moderate cytostatic activity was recorded for the 5-fluorouracil derivatives.     

Assessing Optimal Target Populations for Influenza Vaccination Programmes: An Evidence Synthesis and Modelling Study

Background

Influenza vaccine policies that maximise health benefit through efficient use of limited resources are needed. Generally, influenza vaccination programmes have targeted individuals 65 y and over and those at risk, according to World Health Organization recommendations. We developed methods to synthesise the multiplicity of surveillance datasets in order to evaluate how changing target populations in the seasonal vaccination programme would affect infection rate and mortality.

Methods and Findings

Using a contemporary evidence-synthesis approach, we use virological, clinical, epidemiological, and behavioural data to develop an age- and risk-stratified transmission model that reproduces the strain-specific behaviour of influenza over 14 seasons in England and Wales, having accounted for the vaccination uptake over this period. We estimate the reduction in infections and deaths achieved by the historical programme compared with no vaccination, and the reduction had different policies been in place over the period. We find that the current programme has averted 0.39 (95% credible interval 0.34–0.45) infections per dose of vaccine and 1.74 (1.16–3.02) deaths per 1,000 doses. Targeting transmitters by extending the current programme to 5–16-y-old children would increase the efficiency of the total programme, resulting in an overall reduction of 0.70 (0.52–0.81) infections per dose and 1.95 (1.28–3.39) deaths per 1,000 doses. In comparison, choosing the next group most at risk (50–64-y-olds) would prevent only 0.43 (0.35–0.52) infections per dose and 1.77 (1.15–3.14) deaths per 1,000 doses.

Conclusions

This study proposes a framework to integrate influenza surveillance data into transmission models. Application to data from England and Wales confirms the role of children as key infection spreaders. The most efficient use of vaccine to reduce overall influenza morbidity and mortality is thus to target children in addition to older adults. Please see later in the article for the Editors'' Summary