Caenorhabditis elegans oocytes, like those of most animals, arrest during meiotic prophase. Sperm promote the resumption of meiosis (maturation) and contraction of smooth muscle-like gonadal sheath cells, which are required for ovulation. We show that the major sperm cytoskeletal protein (MSP) is a bipartite signal for oocyte maturation and sheath contraction. MSP also functions in sperm locomotion, playing a role analogous to actin. Thus, during evolution, MSP has acquired extracellular signaling and intracellular cytoskeletal functions for reproduction. Proteins with MSP-like domains are found in plants, fungi, and other animals, suggesting that related signaling functions may exist in other phyla.

The vacA gene of Helicobacter pylori strain 60190 encodes a 1,287-amino-acid protoxin, which undergoes cleavage of a 33-amino-acid amino-terminal signal sequence and carboxy-terminal proteolytic processing to yield a mature secreted toxin. Several features of VacA suggest that it belongs to the autotransporter family of gram-negative bacterial secreted proteins. Based on matrix-assisted laser desorption ionization-time of flight mass spectrometric analysis, we calculate that the mature toxin has a mass of 88.2 ؎ 0.2 kDa and consists of approximately 821 amino acids.Chronic colonization of the human gastric mucosa by Helicobacter pylori is associated with gastritis and an increased risk for development of peptic ulcer disease and gastric malignancies (5). Most H. pylori strains secrete a toxin (VacA) that induces multiple structural and functional alterations in eukaryotic cells (see references 1 and 10 for reviews). H. pylori vacA encodes an ϳ139-kDa protoxin, which undergoes cleavage of a 33-amino-acid amino-terminal signal sequence and carboxy-terminal proteolytic processing to yield a mature secreted toxin (2, 4, 14, 15) (see GenPept accession number B53739). In various studies, the reported masses of mature secreted VacA toxins have varied from 87 to 95 kDa, based on analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (2, 4, 14, 15). Thus, the site (or sites) at which the VacA protoxin undergoes carboxy-terminal proteolytic processing is not known. In this study, we used matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry to determine the precise molecular mass of the secreted VacA toxin.H. pylori strain 60190 (ATCC 49503) was cultured for 48 h at 37°C in sulfite-free brucella broth containing 0.5% charcoal. VacA was purified in an oligomeric form from the culture supernatant, as described previously (3). Purified VacA preparations were analyzed by MALDI-TOF mass spectrometry, using a Voyager Elite (PerSeptive Biosystems, Framingham, Mass.) instrument equipped with a pulsed nitrogen laser source operating at 337 nm. Mass spectra were obtained in the delayed-extraction positive ion mode with an accelerating voltage of 25 kV. Sinapinic acid (10 mg/ml in 70:30 [vol/vol] acetonitrile-0.1% trifluoroacetic acid) was used as a matrix additive. The instrument was calibrated externally with bovine serum albumin (MH ϩ ϭ 66,431) for analysis of intact VacA and was calibrated with bovine insulin (MH ϩ ϭ 5,734.6) for analysis of VacA peptides. The molecular masses reported in this paper are those of single-protonated species (MH ϩ ). Based on MALDI-TOF analysis of purified VacA, we calculated the molecular mass of VacA monomers to be 88.2 Ϯ 0.2 kDa (value is mean Ϯ standard deviation, as are values given below) (Fig. 1). Purified VacA degrades during prolonged storage into two fragments (of about 34 and 58 kDa, respectively) which are derived from the amino terminus and the carboxy terminus of the toxin, respectively (3, 15). Mass spectrometric analysis of partially ...

A visible-light-responsive metal−organic framework based on titanium hexameric cluster and high conjugation system of organic linker building block termed MOF-902 was synthesized and fully characterized. The photocatalytic properties of MOF-902 were investigated in the polymerization reaction with various monomers such as methyl methacrylate (MMA), benzyl methacrylate (BMA), and styrene (St), respectively. Gel permeation chromatography (GPC) analysis results demonstrated the high performance of MOF-902 as a catalyst, affording polymer products with high molecular weight (M n ) and low polydispersity index (PDI). The photocatalytic efficiency of MOF-902 in the polymerization transformation obviously exceeds other catalysts such as MOF-901, UiO-66, UiO-66-NH 2 , MIL-125(Ti), MIL-125-NH 2 (Ti), and commercial P25-TiO 2 .

We describe a technique for rapid stand-off detection of trace explosives and other analytes of interest. An infrared ͑IR͒ laser is directed to a surface of interest, which is viewed using a thermal imager. Resonant absorption by the analyte at specific IR wavelengths selectively heats the analyte, providing a thermal contrast with the substrate. The concept is demonstrated using trinitrotoluene and cyclotrimethylenetrinitramine on transparent, absorbing, and reflecting substrates. Trace explosives have been detected from particles as small as 10 m.

The first 57 bp upstream of the transcription initiation site of the human CYP17 (hCYP17) gene are essential for both basal and cAMP-dependent transcription. EMSA carried out by incubating H295R adrenocortical cell nuclear extracts with radiolabeled -57/-38 probe from the hCYP17 promoter showed the formation of three DNA-protein complexes. The fastest complex contained steroidogenic factor (SF-1) and p54(nrb)/NonO, the intermediate complex contained p54(nrb)/NonO and polypyrimidine tract-binding protein-associated splicing factor (PSF), and the slowest complex contained an SF-1/PSF/p54(nrb)/NonO complex. (Bu)(2)cAMP treatment resulted in a cAMP-inducible increase in the binding intensity of only the upper complex and also activated hCYP17 gene transcription. SF-1 coimmunoprecipitated with p54(nrb)/NonO, indicating direct interaction between these proteins. Functional assays revealed that PSF represses basal transcription. Further, the repression of hCYP17 promoter-reporter construct luciferase activity resulted from PSF interacting with the corepressor mSin3A. Trichostatin A attenuated the inhibition of basal transcription, suggesting that a histone deacetylase interacts with the SF-1/PSF/p54(nrb)/NonO/mSin3A complex. Our studies lend support to the idea that the balance between transcriptional activation and repression is essential in the control of adrenocortical steroid hormone biosynthesis.

BackgroundCarbon nanotube (CNT) characteristics, besides the processing conditions, can change significantly the microwave absorption behavior of CNT/polymer composites. In this study, we investigated the influence of three commercial multi-walled CNT materials with various diameters and length-to-diameter aspect ratios on the X-band microwave absorption of epoxy nanocomposites with CNT contents from 0.125 to 2 wt%, prepared by two dispersion methods, i.e. in solution with surfactant-aiding and via ball-milling.ResultsThe laser diffraction particle size and TEM analysis showed that both methods produced good dispersions at the microscopic level of CNTs. Both a high aspect ratio resulting in nanotube alignment trend and good infiltration of the matrix in the individual nanotubes, which was indicated by high Brookfield viscosities at low CNT contents of CNT/epoxy dispersions, are important factors to achieve composites with high microwave absorption characteristics. The multi-walled carbon nanotube (MWCNT) with the largest aspect ratio resulted in composites with the best X-band microwave absorption performance, which is considerably better than that of reported pristine CNT/polymer composites with similar or lower thicknesses and CNT loadings below 4 wt%.ConclusionsA high aspect ratio of CNTs resulting in microscopic alignment trend of nanotubes as well as a good level of micro-scale CNT dispersion resulting from good CNT-matrix interactions are crucial to obtain effective microwave absorption performance. This study demonstrated that effective radar absorbing MWCNT/epoxy nanocomposites having small matching thicknesses of 2–3 mm and very low filler contents of 0.25-0.5 wt%, with microwave energy absorption in the X-band region above 90% and maximum absorption peak values above 97%, could be obtained via simple processing methods, which is promising for mass production in industrial applications.Graphical AbstractComparison of the X-band microwave reflection loss of epoxy composites of various commercial multi-walled carbon nanotube materials.

Urethane-thiourethane networks combining shape memory properties and the ability to self-heal under mild temperature conditions via Diels-Alder (DA) chemistry were developed. As a result of the shape recovery effect, no external force was needed to bring the fracture surfaces into intimate contact during the healing process. Four network architectures with DA net-points were evaluated. Two systems were composed of either bismaleimidic or bisfuranic semi-crystallized polycaprolactone chains acting as shape memory switching segments (T trans = T m ), whereas the other two networks consisted of bis-/trismaleimidic and trisfuranic monomers and displayed glass transitions for initiating shape recovery behaviour (T trans = T g ). The formation of the DA cross-links, the DA reversibility and shape memory assisted scratch healing of the materials were studied by FTIR and 1 H-NMR spectrometry, differential scanning calorimetry, optical microscopy and tensile measurements. The results indicated that the healing efficiency of scratches depends strongly on the shape recovery ability, without which crack closure and thus the healing reaction could not occur. Two materials were found to feature good shape memory properties as well as efficient scratch-healing capacities, showing mechanical recoveries of 70-80% and the almost complete disappearance of scratches after healing at a mild temperature of 60°C for 1-3 days. These materials could find applications in diverse fields such as self-healing coatings.Scheme 1 Chemical structures of the (thio)urethane multi-maleimide and multi-furan monomers and schematic depiction of the SM networks reversibly cross-linked by the DA reaction. Polymer Chemistry PaperThis journal is

The homology-independent targeted integration (HITI) strategy enables effective CRISPR/Cas9-mediated knockin of therapeutic genes in nondividing cells in vivo, promising general therapeutic solutions for treating genetic diseases like Xlinked juvenile retinoschisis. Herein, supramolecular nanoparticle (SMNP) vectors are used for codelivery of two DNA plasmids-CRISPR-Cas9 genome-editing system and a therapeutic gene, Retinoschisin 1 (RS1)-enabling clustered regularly interspaced short palindromic repeats (CRISPR)-associated protein 9 (CRISPR/Cas9) knockin of the RS1 gene with HITI. Through small-scale combinatorial screenings, two SMNP vectors, with Cas9 and single guide RNA (sgRNA)plasmid in one and Donor-RS1 and green fluorescent protein (GFP)-plasmid in the other, with optimal delivery performances are identified. These SMNP vectors are then employed for CRISPR/Cas9 knockin of RS1/GFP genes into the mouse Rosa26 safe-harbor site in vitro and in vivo. The in vivo study involves intravitreally injecting the two SMNP vectors into the mouse eyes, followed by repeated ocular imaging by fundus camera and optical coherence tomography, and pathological and molecular analyses of the harvested retina tissues. Mice ocular organs retain their anatomical integrity, a single-copy 3.0-kb RS1/GFP gene is precisely integrated into the Rosa26 site in the retinas, and the integrated RS1/GFP gene is expressed in the retinas, demonstrating CRISPR/Cas9 knockin of RS1/GFP gene.