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Nuclear pore complexes play central roles as gatekeepers of RNA and protein transport between the cytoplasm and nucleoplasm. However, their large size and dynamic nature have impeded a full structural and functional elucidation. Here we determined the structure of the entire 552-protein nuclear pore complex of the yeast Saccharomyces cerevisiae at sub-nanometre precision by satisfying a wide range of data relating to the molecular arrangement of its constituents. The nuclear pore complex incorporates sturdy diagonal columns and connector cables attached to these columns, imbuing the structure with strength and flexibility. These cables also tie together all other elements of the nuclear pore complex, including membrane-interacting regions, outer rings and RNA-processing platforms. Inwardly directed anchors create a high density of transport factor-docking Phe-Gly repeats in the central channel, organized into distinct functional units. This integrative structure enables us to rationalize the architecture, transport mechanism and evolutionary origins of the nuclear pore complex.

Membranes and membrane proteins destined for peroxisomes are trafficked from the endoplasmic reticulum (ER) in preperoxisomal vesicles. Mast et al. define a role for ESCRT-III in releasing these vesicles from the ER., Dynamic control of peroxisome proliferation is integral to the peroxisome’s many functions. The endoplasmic reticulum (ER) serves as a source of preperoxisomal vesicles (PPVs) that mature into peroxisomes during de novo peroxisome biogenesis and support growth and division of existing peroxisomes. However, the mechanism of PPV formation and release from the ER remains poorly understood. In this study, we show that endosomal sorting complexes required for transport (ESCRT)-III are required to release PPVs budding from the ER into the cytosol. Absence of ESCRT-III proteins impedes de novo peroxisome formation and results in an aberrant peroxisome population in vivo. Using a cell-free PPV budding assay, we show that ESCRT-III proteins Vps20 and Snf7 are necessary to release PPVs from the ER. ESCRT-III is therefore a positive effector of membrane scission for vesicles budding both away from and toward the cytosol. These findings have important implications for the evolutionary timing of emergence of peroxisomes and the rest of the internal membrane architecture of the eukaryotic cell.

The study of malaria parasites on the Indian subcontinent should help us understand unexpected disease outbreaks and unpredictable disease presentations from Plasmodium falciparum and from Plasmodium vivax infections. The Malaria Evolution in South Asia (MESA) research program is one of ten International Centers of Excellence for Malaria Research (ICEMR) sponsored by the US National Institute of Health. In this second of two reviews, we describe why population structures of Plasmodia in India will be characterized and how we will determine their consequences on disease presentation, outcome and patterns. Specific projects will determine if genetic diversity, possibly driven by parasites with higher genetic plasticity, plays a role in changing epidemiology, pathogenesis, vector competence of parasite populations, and whether innate human genetic traits protect Indians from malaria today. Deep local clinical knowledge of malaria in India will be supplemented by basic scientists who bring new research tools. Such tools will include whole genome sequencing and analysis methods; in vitro assays to measure genome plasticity, RBC cytoadhesion, invasion, and deformability; mosquito infectivity assays to evaluate changing parasite-vector compatibilities; and host genetics to understand protective traits in Indian populations. The MESA-ICEMR study sites span diagonally across India, including a mixture of very urban and rural hospitals, each with very different disease patterns and patient populations. Research partnerships include government-associated research institutes, private medical schools, city and state government hospitals, and hospitals with industry ties. Between 2012-2017, in addition to developing clinical research and basic science infrastructure at new clinical sites, our training workshops will engage new scientists and clinicians throughout South Asia in the malaria research field.

Silica colloids embedded with superparamagnetic iron oxide nanoparticles were synthesized by combining commercial ferrofluids with the well-known Stober process. In a typical procedure, organophilic iron oxide nanoparticles were extracted from a ferrofluid and redispersed in toluene. The suspension was then added to an alcoholic medium to produce emulsion drops consisting of aggregates of iron oxide nanoparticles and toluene. When tetraethylorthosilicate was introduced into the system, it hydrolyzed and formed silica coating around each emulsion drop. The final size of silica colloids depended on the concentration of iron oxide nanoparticles and the type of solvent used for the Stober synthesis. Larger colloids were obtained at lower concentrations of iron oxide nanoparticles and in alcohols with higher molecular weights.

Morphological control over platinum nanoparticles was realized by varying the amount of NaNO3 added to a polyol process, where H2PtCl6 was reduced by ethylene glycol to form PtCl42- and Pt0 at 160 °C. As the molar ratio between NaNO3 and H2PtCl6 was increased from 0 to 11, the morphology of Pt nanoparticles evolved from irregular spheroids with rounded profiles to tetrahedra and octahedra with well-defined facets. Absorption spectroscopy studies suggest that nitrate was reduced to nitrite by PtCl42- in the early stage of the synthesis, and the nitrite could then form stable complexes with both Pt(II) and Pt(IV) species. As a result, the reduction of Pt precursors by ethylene glycol was greatly slowed. This change in reaction kinetics altered the growth rates associated with different crystallographic directions of the Pt nanocrystals and ultimately led to the formation of different morphologies.

Single-crystal cubes and tetrahedrons of silver with truncated corners/edges have been prepared for the first time in high yields by reducing silver nitrate with ethylene glycol heated to 148 °C in the presence of poly(vinyl pyrrolidone) and a trace amount of sodium chloride. These nanoparticles were relatively monodisperse in size and shape, and their dimensions could be readily controlled in the range of 20 to 80 nm by varying the reaction time and other experimental parameters. We propose that the defects inherent in twinned nuclei of silver led to their selective etching and dissolution by chloride and oxygen (from air), leaving only the single crystalline ones to grow into nanoscale cubes and tetrahedrons.

A solution-phase, precursor method has been demonstrated for the large-scale synthesis of single crystalline nanowires of lead with uniform diameters in the range 50−90 nm and lengths up to several...

This paper describes a solution-phase route to the facile synthesis of lead nanowires with lateral dimensions as thin as 35 nm and lengths up to 250 μm. These lead nanowires were single crystalline in structure, and electron transport measurements on individual nanowires (using the four-probe method) indicate a phase transition to the superconducting state around 7.13 K, a temperature similar to the value (7.20 K) reported for bulk lead. Different from polycrystalline samples, no significant variation in the transition temperature was observed for nanowires with diameters down to 50 nm.

We have recently demonstrated an approach based on the polyol process for the large-scale synthesis of silver nanowires with uniform diameters (see Sun, Y.; Gates, B.; Mayers, B.; Xia, Y. Nano Lett. 2002, 2, 165. Sun, Y.; Xia, Y. Adv. Mater. 2002, 14, 833. Sun, Y.; Yin, Y.; Mayers, B. T.; Herricks, T.; Xia, Y. Chem. Mater. 2002, 14, 4736). Although the capability and feasibility of this method have been successfully illustrated with the production of silver nanowires 30−60 nm in diameter and 1−50 μm in length, the growth mechanism of this process is yet to be elucidated. Here we report some progress on this matter: First, electron microscopy studies on microtomed samples indicated that the cross sections of such silver nanowires had a pentagonal shape, together with a 5-fold twinned crystal structure. Second, the side surfaces (bounded by {100} facets) and the ends (bounded by {111} facets) of each nanowire were shown to have significant difference in reactivity toward dithoil molecules, with the side su...

This letter describes a simple procedure for fabricating randomly and uniaxially aligned nanofibers of nickel ferrite by electrospinning. Polycrystalline nanofibers of NiFe2O4 with an average diameter of 46 nm have been prepared by electrospinning a solution that contained poly(vinyl pyrrolidone) and alkoxide precursors to nickel and iron oxides, followed by hydrolysis and calcination at 550 °C in air. Magnetic hysteresis scans were performed on these nanofibers, in comparison with a powder sample prepared using the conventional sol–gel process. Significant differences in magnetic properties were noted between these two samples, and these differences seemed to be associated with the size and morphological differences between the nanofibers and the powders.

Splenic filtration of Plasmodium falciparum infected red blood cells has been hypothesized to influence malaria pathogenesis. We have developed a minimum cylindrical diameter (MCD) filtration model which estimates physical splenic filtration during malaria infection. The key parameter in the model is the minimum cylindrical diameter (MCD), the smallest tube or cylinder that a red blood cell (RBC) can traverse without lysing. The MCD is defined by a relationship between the RBC surface area and volume. In the MCD filtration model, the MCD filtration function represents the probability of a cell becoming physically removed from circulation. This modeling approach was implemented at a field site in Blantyre, Malawi. We analyzed peripheral blood samples from 120 study participants in 4 clinically defined groups (30 subjects each): cerebral malaria, uncomplicated malaria, aparasitemic coma, and healthy controls. We found statistically significant differences in the surface area and volumes of uninfected RBCs when healthy controls were compared to malaria patients. The estimated filtration rates generated by the MCD model corresponded to previous observations in ex vivo spleen experiments and models of red blood cell loss during acute malaria anemia. There were no differences in the estimated splenic filtration rates between cerebral malaria and uncomplicated malaria patients. The MCD filtration model estimates that at time of admission, 1 ring-stage infected RBC is physically filtered by the spleen for each parasite that remains in peripheral circulation. This field study is the first to use microfluidic devices to identify rheological diversity in RBC populations associated with malaria infection and illness in well characterized groups of children living in a malaria endemic area.

Nanofibers consisting of enzyme–polymer composites have been prepared by directly electrospinning a solution of surfactant-stabilized enzyme and polymer in toluene. Additional treatment with glutaraldehyde could greatly stabilize the enzyme activity of the fibers, which could be maintained in a buffer under shaking conditions for more than two weeks. The nanofibers also showed great improvement in the enzyme activity over bulk films as a result of increased mass-transfer for substrate molecules to and from the enzyme reactive sites. These stable and catalytically active nanofiber-based mats were highly durable and could be easily recovered from solution, making them ideal candidates for large scale applications.