Synthesis of Novel Chiral Tridentate Schiff‐Base Ligands and Their Applications in Catalytic Asymmetric Henry Reaction

A series of chiral tridentate Schiff‐bases were prepared and used as ligands in the catalytic asymmetric Henry reaction. Under the optimal conditions, a variety of arylaldehydes were smoothly converted into corresponding adducts with high yields (up to 98%) and excellent enantioselectivities (up to 97% ee). Chirality 26: 780–783, 2014. © 2014 Wiley Periodicals, Inc.     

Durch Seitenwurzelbildung induzierte und spontane Mitosen in den Dauergeweben der Wurzel

Ohne ZusammenfassungDie wesentlichen Untersuchungsergebnisse wurden im Rahmen einer Doktorarbeit am Botanischen Institut der Universität Wien gewonnen. Für Anregung und förderliche Kritik danken wir Herrn Prof. Dr. L.Geitler bestens.     

Chromatin interacting factor OsVIL2 increases biomass and rice grain yield

Grain number is an important agronomic trait. We investigated the roles of chromatin interacting factor Oryza sativa VIN3‐LIKE 2 (OsVIL2), which controls plant biomass and yield in rice. Mutations in OsVIL2 led to shorter plants and fewer grains whereas its overexpression (OX) enhanced biomass production and grain numbers when compared with the wild type. RNA‐sequencing analyses revealed that 1958 genes were up‐regulated and 2096 genes were down‐regulated in the region of active division within the first internodes of OX plants. Chromatin immunoprecipitation analysis showed that, among the downregulated genes, OsVIL2 was directly associated with chromatins in the promoter region of CYTOKININ OXIDASE/DEHYDROGENASE2 (OsCKX2), a gene responsible for cytokinin degradation. Likewise, active cytokinin levels were increased in the OX plants. We conclude that OsVIL2 improves the production of biomass and grain by suppressing OsCKX2 chromatin.     

The effector SIX8 is required for virulence of Fusarium oxysporum f.sp. cubense tropical race 4 to Cavendish banana

Plant pathogens employ effectors as molecular weapons to manipulate host immunity and facilitate colonization. Fusarium oxysporum f. sp. cubense is the agent of wilt disease in banana plantlets and four races of the pathogen have been identified based on the cultivar specificity. A total of 9 SIX genes have been detected in the genome of Foc TR4 and 6 genes detected in Foc1. Among these SIX genes, SIX2 and SIX8 are only detected in Foc TR4, not identified in Foc1. Expression profiles analysis revealed that SIX genes of Foc TR4 are highly induced after inoculation to Cavendish banana plantlets. Virulence analysis of the SIX2 and SIX8 knock-out mutants showed that SIX8 is required for the virulence of Foc TR4 while SIX2 has no obvious functions. Over expression of SIX8-FLAG proteins in the SIX8 knock-out mutant partly restored the virulence. Western blot analysis suggested that SIX8 could be secreted into the extracellular space and a signal peptide resided the N-terminal polypeptide sequence. This study provides some clues for further research on mechanism of SIX8 in regulating virulence of Foc TR4.     

Responses of Bacterial Communities to Simulated Climate Changes in Alpine Meadow Soil of the Qinghai-Tibet Plateau

The soil microbial community plays an important role in terrestrial carbon and nitrogen cycling. However, microbial responses to climate warming or cooling remain poorly understood, limiting our ability to predict the consequences of future climate changes. To address this issue, it is critical to identify microbes sensitive to climate change and key driving factors shifting microbial communities. In this study, alpine soil transplant experiments were conducted downward or upward along an elevation gradient between 3,200 and 3,800 m in the Qinghai-Tibet plateau to simulate climate warming or cooling. After a 2-year soil transplant experiment, soil bacterial communities were analyzed by pyrosequencing of 16S rRNA gene amplicons. The results showed that the transplanted soil bacterial communities became more similar to those in their destination sites and more different from those in their “home” sites. Warming led to increases in the relative abundances in Alphaproteobacteria, Gammaproteobacteria, and Actinobacteria and decreases in Acidobacteria, Betaproteobacteria, and Deltaproteobacteria, while cooling had opposite effects on bacterial communities (symmetric response). Soil temperature and plant biomass contributed significantly to shaping the bacterial community structure. Overall, climate warming or cooling shifted the soil bacterial community structure mainly through species sorting, and such a shift might correlate to important biogeochemical processes such as greenhouse gas emissions. This study provides new insights into our understanding of soil bacterial community responses to climate warming and cooling.     

Structure of solid-supported lipid membrane probed by noble metal nanoparticle deposition

Direct deposition of a noble metal layer onto a solid-supported membrane was proposed as an indirect microscopy tool to visually observe different lipid phases that may develop in the lipid membrane. The method relied on the different permeability of the lipid membrane towards the incident atoms during deposition. Liquid state or structural defects such as phase boundaries, step ledges in a multi-lamellar stack, and pores permitted the metal atoms to penetrate and nucleate inside the membrane whereas rigid gel state was relatively impermeable to the incident atoms, thus enabling visualization of liquid phase or structural defects inside the gel state. Based on the proposed method, we demonstrated the phase states resulting from thermotropic transitions of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), dioleoylphosphatidylethanolamine (DOPE)/DPPC mixture, and 1,2-dioleoyl-3-trimethylammonium propane (DOTAP). Although the proposed method does not allow in-situ observation of equilibrium states, the method should be an excellent complementary tool for visualizing the lipid phases as the method can resolve fine structural details (up to tens of nanometer scale) as seen in the DPPC membrane while providing macroscopic images (up to several micrometers).     

Vitamin D and physical performance in elderly subjects: the Pro.V.A study

Background

The role of Vitamin D in musculoskeletal functionality among elderly people is still controversial. We investigated the association between serum 25-hydroxyvitamin D (25OHD) levels and physical performance in older adults.

Methods

2694 community-dwelling elderly women and men from the Progetto Veneto Anziani (Pro.V.A.) were included. Physical performances were assessed by: tandem test, 5 timed chair stands (TCS), gait speed, 6-minute walking (6 mW) distance, handgrip strength, and quadriceps strength. For each test, separate general linear models and loess plots were obtained in both genders, in relation to serum 25OHD concentrations, controlling for several potential confounders.

Results

Linear associations with 25OHD levels were observed for TCS, gait speed, 6 mW test and handgrip strength, but not for tandem test and quadriceps strength. After adjusting for potential confounders, linear associations with 25OHD levels were still evident for the 6 mW distance in both genders (p = .0002 in women; <.0001 in men), for TCS in women (p = .004) and for gait speed (p = .0006) and handgrip strength (p = .03) in men. In loess analyses, performance in TCS in women, in gait speed and handgrip strength in men and in 6 mW in both genders, improved with increasing levels of 25OHD, with most of the improvements occurring for 25OHD levels from 20 to 100 nmol/L.

Conclusion

lower 25OHD levels are associated with a worse coordination and weaker strength (TCS) in women, a slower walking time and a lower upper limb strength in men, and a weaker aerobic capacity (6 mW) in both genders. For optimal physical performances, 25OHD concentrations of 100 nmol/L appear to be more advantageous in elderly men and women, and Vitamin D supplementation should be encouraged to maintain their 25OHD levels as high as this threshold.