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Recombinant adeno-associated virus (rAAV) vector gene delivery systems have demonstrated great promise in clinical trials but continue to face durability and dose-related challenges. Unlike rAAV gene therapy, integrating gene addition approaches can provide curative expression in mitotically active cells and pediatric populations. We explored a novel in vivodelivery approach based on an engineered transposase, Sleeping Beauty(SB100X), delivered as an mRNA within a lipid nanoparticle (LNP), in combination with an rAAV-delivered transposable transgene. This combinatorial approach achieved correction of ornithine transcarbamylase deficiency in the neonatal Spfashmouse model following a single delivery to dividing hepatocytes in the newborn liver. Correction remained stable into adulthood, while a conventional rAAV approach resulted in a return to the disease state. In non-human primates, integration by transposition, mediated by this technology, improved gene expression 10-fold over conventional rAAV-mediated gene transfer while requiring 5-fold less vector. Additionally, integration site analysis confirmed a random profile while specifically targeting TA dinucleotides across the genome. Together, these findings demonstrate that transposable elements can improve rAAV-delivered therapies by lowering the vector dose requirement and associated toxicity while expanding target cell types.

A reflective tactile sensing scheme based on fiber specklegram analysis is proposed in this study. The specially designed sensor probe with a reflector inside was 3D printed from elastic material. A section of single mode fiber (SMF) and a section of multimode fiber (MMF) were embedded under the reflector. The light emitted from the SMF is reflected by the reflector and the reflected light illuminates the MMF. At the output facet of the MMF, specklegram is detected by a camera. The reflector consists of two soft mirrors that are perpendicular to each other originally. The contact force on the sensor probe causes the variation of the angle between the two mirrors. The transmission path of the light from SMF to MMF changes accordingly, which results in a changed specklegram. In this way, the zero-mean normalized cross-correlation coefficients of the fiber specklegrams decrease linearly with the increase of contact force. The sensitivity and measurement range of contact force are examined with MMFs of different diameters under two operating wavelengths. The negligible effect of fiber bending on the force sensing was also experimentally confirmed. In addition, the convolutional neural network is used to classify the specklegrams of three contact forces applied at nine positions of the sensor probe, and the average accuracy of classification is 100%, which shows its capability to identify the contact position on the probe. On the whole, the proposed tactile sensor is confirmed with a high sensitivity of force sensing in a proper measurement range and a capability to localize the contact position. The reflective structure also facilitates the integration with robot arm and other intelligent structures.

SummaryIn order to find the optimal subsurface drip irrigation (SDI) scheduling for mature triploid Populus tomentosaplantations in the North China Plain, a field experiment was conducted in 2010 and 2011 to investigate the effects of SDI at different soil water potential (SWP) thresholds on the growth and transpiration of a P. tomentosaplantation when it was six and seven years old. The experiment included three SWP treatments, which initiated irrigation when the SWP at 20 cm depth and 10 cm distance from a drip emitter reached −25 (T25), −50 (T50) and −75 (T75) kPa, respectively. A control non-irrigation treatment (CK) was also included. Long-term SWP, soil water content (SWC), transpiration, tree growth, meteorological factors and groundwater level were monitored. Results showed that SDI influenced the SWC only in 0–80 cm of soil. From April to July, on average, the cumulative stand-level transpiration on a ground area basis (E) and growth of basal area at breast height accounted for 81% and 93% of their corresponding whole-season values, while the cumulative reference crop potential evapotranspiration (ET0) was 43% higher than the rainfall. In contrast, from August to October, the growth rate of P. tomentosawas very slow, while the cumulative rainfall was 36% higher than ET0and the average groundwater level was relatively high (125 cm). Relative to CK, the Eunder the SWP treatments was significantly (P < 0.05) increased by 20–73%. Decreasing the SWP irrigation threshold from −25 to −50 kPa significantly reduced Eby 31% (P < 0.05), but decreasing the threshold from −50 to −75 kPa did not further reduce P. tomentosa E. Relative to CK, T25, T50and T75increased the annual above-ground dry biomass (ADB) increment by 54% (P < 0.05), 34% (P < 0.05) and 24% (P> 0.05) in 2010, and by 28% (P> 0.05), 29% (P> 0.05) and 32% (P< 0.05) in 2011, respectively. However, no significant difference in ADB increment was detected among the SWP treatments. Based on these results, it can be concluded that when planting P. tomentosaat sites with similar characteristics to ours in the North China Plain: (1) SDI could be promoted in the cultivation of P. tomentosato improve tree growth; (2) a range of −50 to −75 kPa at a depth of 20 cm and 10 cm distant from a drip emitter is recommended as the irrigation threshold for scheduling SDI in P. tomentosaplantations and (3) irrigation should be applied between April and July, while drainage should be implemented between August and October.

ABSTRACTThe nucleocapsid protein (NC) of retroviruses plays a major role in genomic RNA packaging, and some evidence has implicated the matrix protein (MA) of certain retroviruses in viral RNA binding. To further investigate the role of NC in the selective recognition of genomic viral RNA and to address the potential contribution of MA in this process, we constructed chimeric and deletion human immunodeficiency virus type 1 (HIV-1) mutants that alter the NC or MA protein. Both HIV and mouse mammary tumor virus (MMTV) NC proteins have two zinc-binding domains and similar basic amino acid compositions but differ substantially in total length, amino acid sequence, and spacing of the zinc-binding motifs. When the entire NC coding sequence of HIV was replaced with the MMTV NC coding sequence, we found that the HIV genome was incorporated into virions at 50% of wild-type levels. Viruses produced from chimeric HIV genomes with complete NC replacements, or with the two NC zinc-binding domains replaced with MMTV sequences, preferentially incorporated HIV genomes when both HIV and MMTV genomes were simultaneously present in the cell. Viruses produced from chimeric MMTV genomes in which the MMTV NC had been replaced with HIV NC preferentially incorporated MMTV genomes when both HIV and MMTV genomes were simultaneously present in the cell. In contrast, viruses produced from chimeric HIV genomes containing the Moloney NC, which contains a single zinc-binding motif, were previously shown to preferentially incorporate Moloney genomic RNA. Taken together, these results indicate that an NC protein with two zinc-binding motifs is required for specific HIV RNA packaging and that the amino acid context of these motifs, while contributing to the process, is less crucial for specificity. The data also suggest that HIV NC may not be the exclusive determinant of RNA selectivity. Analysis of an HIV MA mutant revealed that specific RNA packaging does not require MA protein.