Multilayer DNA Origami with Terminal Interfaces That Are Flat and Wide-Area.

DNA origami is a popular nanofabrication strategy that employs self-assembly of a long single scaffold strand, typically less than 10 kilobases in length, with hundreds of shorter staple strands into a desired shape. In particular, origami arranged as a single-layer rectangle has proven popular as flat pegboards that can display functionalities at staple-strand breakpoints, off the sides of the constituent double helices, with a ∼5.3 nm rhombic-lattice spacing.

Structure of the peroxisomal Pex1/Pex6 ATPase complex bound to a substrate.

The double-ring AAA+ ATPase Pex1/Pex6 is required for peroxisomal receptor recycling and is essential for peroxisome formation. Pex1/Pex6 mutations cause severe peroxisome associated developmental disorders. Despite its pathophysiological importance, mechanistic details of the heterohexamer are not yet available.

Asymmetric horseshoe-like assembly of peroxisomal yeast oxalyl-CoA synthetase.

Oxalyl-CoA synthetase from is one of the most abundant peroxisomal proteins in yeast and hence has become a model to study peroxisomal translocation. It contains a C-terminal Peroxisome Targeting Signal 1, which however is partly dispensable, suggesting additional receptor bindings sites. To unravel any additional features that may contribute to its capacity to be recognized as peroxisomal target, we determined its assembly and overall architecture by an integrated structural biology approach, including X-ray crystallography, single particle cryo-electron microscopy and small angle X-ray scattering.

Three-phase DNA-origami stepper mechanism based on multi-leg interactions.

Nanoscale stepper motors such as kinesin and dynein play a key role in numerous natural processes such as mitotic spindle formation during cell division or intracellular organelle transport. Their high efficacy in terms of operational speed and processivity has inspired the investigation of biomimetic technologies based on the use of programmable molecules. In particular, several designs of molecular walkers have been explored using DNA nanotechnology.

Coordination Cage-Based Emulsifiers: Templated Formation of Metal Oxide Microcapsules Monitored by In Situ LC-TEM.

Metallo-supramolecular self-assembly has yielded a plethora of discrete nanosystems, many of which show competence in capturing guests and catalyzing chemical reactions. However, the potential of low-molecular bottom-up self-assemblies in the development of structured inorganic materials has rarely been methodically explored so far. Herein, we present a new type of metallo-supramolecular surfactant with the ability to stabilize non-aqueous emulsions for a significant period.

Towards the molecular architecture of the peroxisomal receptor docking complex.

Import of yeast peroxisomal matrix proteins is initiated by cytosolic receptors, which specifically recognize and bind the respective cargo proteins. At the peroxisomal membrane, the cargo-loaded receptor interacts with the docking protein Pex14p that is tightly associated with Pex17p. Previous data suggest that this interaction triggers the formation of an import pore for further translocation of the cargo.

Insights into the Structure and Energy of DNA Nanoassemblies.

Since the pioneering work of Ned Seeman in the early 1980s, the use of the DNA molecule as a construction material experienced a rapid growth and led to the establishment of a new field of science, nowadays called structural DNA nanotechnology. Here, the self-recognition properties of DNA are employed to build micrometer-large molecular objects with nanometer-sized features, thus bridging the nano- to the microscopic world in a programmable fashion. Distinct design strategies and experimental procedures have been developed over the years, enabling the realization of extremely sophisticated structures with a level of control that approaches that of natural macromolecular assemblies.

SPHIRE-crYOLO is a fast and accurate fully automated particle picker for cryo-EM.

Selecting particles from digital micrographs is an essential step in single-particle electron cryomicroscopy (cryo-EM). As manual selection of complete datasets-typically comprising thousands of particles-is a tedious and time-consuming process, numerous automatic particle pickers have been developed. However, non-ideal datasets pose a challenge to particle picking.

Rational Design of an Amphiphilic Coordination Cage-Based Emulsifier.

Self-assembled, porous coordination cages with a functional interior find application in controlled guest inclusion/release, drug delivery, separation processes, and catalysis. However, only few studies exist that describe their utilization for the development of self-assembled materials based on their 3-dimensional shape and external functionalization. Here, dodecyl chain-containing, acridone-based ligands (L) and shape-complementary phenanthrene-derived ligands (L) are shown to self-assemble to heteroleptic coordination cages cis-[Pd(L)(L)] acting as a gemini amphiphile (CGA-1; Cage-based Gemini Amphiphile-1).

Hierarchical Assembly of DNA Filaments with Designer Elastic Properties.

The elastic features of protein filaments are encoded in their component units and in the way they are connected, thus defining a biunivocal relationship between the monomer and the result of its self-assembly. Using DNA origami approaches, we constructed a reconfigurable module, composed of two quasi-independent domains and four possible interfaces, capable of facial and lateral growing through specific recognition patterns. Whereas the flexibility of the intra-domains region can be regulated by switchable DNA motifs, the inter-domain interfaces feature mutually and self-complementary shapes, whose pairwise association leads to filaments of programmable periodicity and variable persistence length.

Boron Partitioning Coefficient above Unity in Laser Crystallized Silicon.

Boron pile-up at the maximum melt depth for laser melt annealing of implanted silicon has been reported in numerous papers. The present contribution examines the boron accumulation in a laser doping setting, without dopants initially incorporated in the silicon wafer. Our numerical simulation models laser-induced melting as well as dopant diffusion, and excellently reproduces the secondary ion mass spectroscopy-measured boron profiles.

Tailored protein encapsulation into a DNA host using geometrically organized supramolecular interactions.

The self-organizational properties of DNA have been used to realize synthetic hosts for protein encapsulation. However, current strategies of DNA-protein conjugation still limit true emulation of natural host-guest systems, whose formation relies on non-covalent bonds between geometrically matching interfaces. Here we report one of the largest DNA-protein complexes of semisynthetic origin held in place exclusively by spatially defined supramolecular interactions.

Group for research in pathology education online resources to facilitate pathology instruction.

Background: The Group for Research in Pathology Education (GRIPE) is an organization of pathology educators whose purpose is to promote and facilitate excellence in pathology education. One important function of GRIPE is the maintenance of image and multiple-choice test question data banks. These resources have recently been made available online via the GRIPE Digital Library Web site.

Role of pulmonary macrophages in resistance to experimental metastasis.

Intranasal inoculation of C3H/HeN mice with Propionibacterium acnes activates pulmonary macrophages but not splenic or peritoneal macrophages. When mice so treated were injected IV with tumor cells, no protection against the challenge was seen. Conversely, inoculation of C3H/HeN mice with P.

Suppressive effects of 3-methylcholanthrene on the in vitro antitumor activity of naturally cytotoxic cells.

Transient suppression of splenic natural killer (NK), natural cytotoxic (NC), and peritoneal macrophage cytotoxicity was observed following a single injection of 3-methylcholanthrene (3-MC) into C3H/HeN mice. Natural killer cell activity was depressed by 30-60% 4-6 d after injection of 1.0 mg 3-MC.

Immune response to ultraviolet-induced tumors. I. Transplantation immunity developing in syngeneic mice in response to progressor ultraviolet-induced tumors.

Ultraviolet-light-induced murine skin tumors were analyzed for the ability to induce transplantation immunity and cytotoxic lymphocytes in syngeneic mice. A correlation was found between tumor regression and the induction of cytotoxic T cells with specificity for a unique tumor-associated antigen. Processing tumors possessed tumor-associated transplantation antigens (TATA), which could be demonstrated by transplantation in hyperimmunized mice.

Experimental uveitis. Elicited by peptidoglycan-polysaccharide complexes, lipopolysaccharide, and muramyl dipeptide.

Uveitis could be a reaction to bacterial debris disseminated to the eye from extraocular sites of infection. In this study, we relate the composition of several bacterial components to their inflammatory properties in the eye. Groups of rabbits were injected intravitreously with peptidoglycan-polysaccharide (PG-PS) complexes isolated from group A streptococci, Escherichia coli lipopolysaccharide (LPS), or synthetic muramyl dipeptide (MDP).

Latent period and antigenicity of murine tumors induced in C3H mice by short-wavelength ultraviolet radiation.

Skin tumors were induced in C3H/HeNCr1BR mice with chronic short-wavelength ultraviolet (UVC) irradiation using a germicidal lamp (254 nm). Fifty percent of mice had developed tumors by 9 1/2 months (range 8-12 months). With progressive irradiation, mice developed multiple tumors on the back reaching a mean of 2.

Specific attachment of collagen to cardiac myocytes: in vivo and in vitro.

The formation and attachment of collagen to the sarcolemma of cardiac myocytes were examined in vivo in neonatal rats and hamsters and in vitro in cultures of neonatal rat myocytes. Scanning, transmission, and high-voltage electron microscopy were used to show that the collagen struts attach to specific sites on the sarcolemma just lateral to the Z band of neonatal animals. In vitro, collagen preferentially attaches to distal end of myocytes at a site where internal stress fibers also attach to the sarcolemma.

Further characterization of immunological unresponsiveness induced in mice by ultraviolet radiation. Growth and induction of nonultraviolet-induced tumors in ultraviolet-irradiated mice.

Ultraviolet (UV)-irradiated mice were compared with unirradiated mice for their susceptibility to primary and transplanted tumors etiologically unrelated to UV radiation. Although UV-irradiated mice are unable to reject transplants of highly antigenic syngeneic tumors induced by UV light, the growth of syngeneic, non-UV-induced tumors generally was not accelerated in these animals. Furthermore, UV-irradiated mice were no more susceptible to the induction of primary leukemias, mammary tumors, or sarcomas than were unirradiated animals.

Distribution of H antigen in persons of blood groups A, B, and AB.

The distribution of H antigen in tissues of persons of blood groups A, B, and AB was examined. H antigen could be demonstrated in all tissues in which the isologous antigens A and B were demonstrated, although some cells demonstrated isologous but not H antigen. In most tissues, areas were seen that demonstrated H antigen but not the isologous antigen.

Identification and cytotoxic reactivity of inflammatory cells recovered from progressing or regressing syngeneic UV-induced murine tumors.

Most tumors induced in C3H mice by ultraviolet (UV) light are immunologically rejected by normal syngeneic recipients, but will grow progressively in immunosuppressed mice and in mice treated with UV light. In this study we compared the composition and cytotoxic activity of the inflammatory cell infiltrate from tumors transplanted into syngeneic UV-irradiated or unirradiated mice. Tumor fragments were implanted in either normal (regressor) or UV-treated (progressor) mice, and removed on various days after implantation and mechanically dissociated.

Accelerated growth of syngeneic tumors in mice treated with methylcholanthrene.

BALB/c and C3H- mice were given a single injection of methylcholanthrene (MCA) and were tested at various times thereafter for immunologic reactivity and resistance to syngeneic tumor challenge. MCA treatment did not affect the rejection of H-2-incompatible tumor allografts, the rejection of H-2-compatible skin allografts, or the induction of delayed hypersensitivity to DNCB as measured by footpad challenge. In contrast, mice treated with MCA exhibited an increase susceptibility to challenge with several syngeneic ultraviolet-induced and MCA-induced fibrosarcomas.