Constructing Linear-Oriented Pre-Vascularized Human Spinal Cord Tissues for Spinal Cord Injury Repair

Repairing spinal cord injury (SCI) is a global medical challenge lacking effective clinical treatment. Developing human-engineered spinal cord tissues that can replenish lost cells and restore a regenerative microenvironment offers promising potential for SCI therapy. However, creating vascularized human spinal cord-like tissues (VSCT) that mimic the diverse cell types and longitudinal parallel structural features of spinal cord tissues remains a significant hurdle. In the present study, VSCTs are engineered using embryonic human spinal cord-derived neural and endothelial cells on linear-ordered collagen scaffolds (LOCS). Studies have shown that astrocytes and endothelial cells align along the scaffolds in VSCT, supporting axon extension from various human neurons myelinated by oligodendrocytes. After transplantation into SCI rats, VSCT survives at the injury sites and promotes endogenous neural regeneration and vascularization, ultimately reducing scarring and enhancing behavioral functional recovery. It suggests that pre-vascularization of engineered spinal cord tissues is beneficial for SCI treatment and highlights the important role of exogenous endothelial cells in tissue engineering.

Rubber latex yield is affected by interactions between antecedent temperature, rubber phenology, and powdery mildew disease

Rubber (Hevea brasiliensis) latex production is crucial to the local economy, yet Xishuangbanna's climate is considered sub-optimal for rubber cultivation. The prevalence of the powdery mildew disease (Oidium heveae) in this region has decreased the annual latex yield by 20%. Rubber latex yield is influenced by several factors, including temperature, disease, other biotic conditions, and plantation management. However, the interrelationships and potential influencing networks between rubber latex yield and these factors are rarely quantitatively assessed, and understanding their impacts on latex yield could inform better management practices. To address this gap, we investigated the effects of temperature, phenology, and powdery mildew disease on rubber latex yield in March using observational data on daily rubber latex yield combined with detailed phenology, powdery mildew, and temperature data from 2004 to 2010 in a state farm in the Xishuangbanna, Yunnan, China. We found that the critical influencing periods of daily temperature difference (or diurnal temperature difference) on the rubber latex yield were during Nov 27-Jan 19 and Jan 21-Mar 17. Partial least square regression analysis and variance partitioning analysis were conducted on the 35 phenological variables, eight powdery mildew-related variables, and two climatic variables. The most influential factors were identified as the factors of the daily temperature differences during Jan-Mar, the duration of leaf flushing phenology, and mean and maximum percentage of leaves infected by powdery mildew. Subsequent canonical correlation analysis and linear regression found that temperature difference directly affected the rubber latex yield and indirectly affected the yield through phenology and powdery mildew disease. Raised daily temperature differences from Jan to Mar had the greatest impact, leading to a higher rubber latex yield. Our comprehensive quantitative assessment revealed the relative importance of antecedent daily temperature differences, phenology, and powdery mildew disease as well as their complex interconnections in influencing rubber latex yield. Our findings are essential to future studies on both powdery mildew disease and rubber latex yield, and also develop rubber latex models.

RPG interacts with E3-ligase CERBERUS to mediate rhizobial infection in Lotus japonicus

Symbiotic interactions between rhizobia and legumes result in the formation of root nodules, which fix nitrogen that can be used for plant growth. Rhizobia usually invade legume roots through a plant-made tunnel-like structure called an infection thread (IT). RPG (Rhizobium-directed polar growth) encodes a coiled-coil protein that has been identified in Medicago truncatula as required for root nodule infection, but the function of RPG remains poorly understood. In this study, we identified and characterized RPG in Lotus japonicus and determined that it is required for IT formation. RPG was induced by Mesorhizobium loti or purified Nodulation factor and displayed an infection-specific expression pattern. Nodule inception (NIN) bound to the RPG promoter and induced its expression. We showed that RPG displayed punctate subcellular localization in L. japonicus root protoplasts and in root hairs infected by M. loti. The N-terminal predicted C2 lipid-binding domain of RPG was not required for this subcellular localization or for function. CERBERUS, a U-box E3 ligase which is also required for rhizobial infection, was found to be localized similarly in puncta. RPG co-localized and directly interacted with CERBERUS in the early endosome (TGN/EE) compartment and near the nuclei in root hairs after rhizobial inoculation. Our study sheds light on an RPG-CERBERUS protein complex that is involved in an exocytotic pathway mediating IT elongation.

Detection of early-universe gravitational-wave signatures and fundamental physics

Detection of a gravitational-wave signal of non-astrophysical origin would be a landmark discovery, potentially providing a significant clue to some of our most basic, big-picture scientific questions about the Universe. In this white paper, we survey the leading early-Universe mechanisms that may produce a detectable signal-including inflation, phase transitions, topological defects, as well as primordial black holes-and highlight the connections to fundamental physics. We review the complementarity with collider searches for new physics, and multimessenger probes of the large-scale structure of the Universe.