Edaphic regulation of soil organic carbon fractions in the mattic layer across the Qinghai-Tibetan Plateau.

The mattic layer is a main ecological function bearer of alpine meadow soils in the Qinghai-Tibet Plateau. It has high soil organic carbon (SOC) content with a variety of SOC fractions, which are thought to have different sensitivities to climate change. The effects of soil properties and climate on the SOC fractions in the mattic layer are not well understood. To address this, we analyzed the effects of environmental factors on two SOC fractions: particulate organic carbon (POC) and mineral-associated organic carbon (MAOC). A random forest model (RFM), partial correlation analysis, and structural equation model (SEM) were used to quantify the relative effects of soil and climatic factors on SOC fractions. We found that SOC and its fractions are primarily regulated by soil properties rather than climate. Partial correlation analysis and SEM revealed that climate indirectly affects SOC by influencing soil properties. Silt+Clay and exchangeable calcium (Caex) were found to be the strongest contributing factors of MAOC and POC, respectively. A distinct shift occurs in the mechanism underlying SOC stabilization with varying soil pH. In acidic and neutral environments, amorphous Al/Fe-(hydr) oxides contribute to the stability of MAOC, whereas free Al/Fe-(hydr) oxides promote SOC mineralization. Conversely, Caex positively influences the stabilization of both POC and MAOC throughout the pH range. These results can be extrapolated to predict SOC dynamics in future soil conditions affected by environmental change, especially for use in Earth system models.

Impact of Brood Cell Cocoons on Metal Accumulation and CYP450 Detoxification Gene Expression in Apis cerana cerana.

Honey bees play a critical role as pollinators. However, their reproduction success and survival face severe threats due to the deterioration of their living environment. Notably, environmental conditions during their preimaginal stage inside brood cells can influence their immune capabilities and overall health after emergence. During the in-cell developmental stage, workers are in close contact with cocoons, which can become a source of stress due to accumulated metals. To investigate this potential threat, experiments were conducted to examine the impact of cocoons in brood cells used to rear different generations on the metal content and detoxification gene expression levels in Apis cerana cerana. Our findings indicated significant differences in the layers, weight, base thickness, and metal contents like Cr, Cd, Pb, Mn, Ni, and As of cocoons in multi-generation brood cells compared to single-generation brood cells. These increases led to significant elevations in metal levels and upregulations of the four CYP450 detoxification genes in both six-day-old larvae and newly emerged workers. In conclusion, this study highlights the negative impact of cocoons in multi-generation brood cells on bee health and provides evidence supporting the development of rational apiculture management strategies for ecosystem stability.

Nitrate leaching characteristics of red soils from different parent materials in subtropical China.

Globally, nitrate (NO3-) leaching from agroecosystems has been of major concern. There is evidence that NO3- leaching exhibits intense seasonal variation in subtropical regions. However, influencing factors to the seasonal dynamics remain unclear. In this study, a two-year field lysimeters experiment was conducted with three red soils derived from different parent materials (Quaternary red clay (QR), red sandstone (RS), and basalt (BA)). An N fertilizer (15N-enriched urea, 10 atom% excess) of 200 kg N ha-1 yr-1 was applied for maize. The effect of parent material on NO3- leaching characteristics was examined in surface (0-20 cm) and subsoil (20-100 cm) layers. The results showed due to the weakening of abundant drainage, there was no significant effect of parent materials on NO3- leaching characteristics in surface layers. Environmental factors (precipitation and temperature) and fertilization together led to obvious seasonal characteristics, i.e. abundant NO3- leaching during both crop growth and fallow periods. In subsoil layers, NO3- leaching characteristics were completely different among three soils. The concentrations and δ15N of NO3- in QR and RS soils showed a continuous increase after first year's fertilization, while those in BA soil remained relatively stable after reaching peak levels around harvest in first year. Meanwhile, the NO3- leaching amount in BA soil was significantly lower than in the other two soils. These might be explained by different NO3- adsorption capacities caused by the differences in mineral composition and free iron and aluminium contents. These elucidated in subsoil layers, NO3- leaching characteristics highly depended on parent materials. Meanwhile, adsorption capacity was limited and cannot slow NO3- leaching in the long run. Our results suggest that seasonal variation of NO3- leaching in surface layers and temporary retardant effect from NO3- adsorption capacity in subsoil layers should receive much attention when calculating and predicting NO3- leaching in subtropical regions.

Pervasive soil phosphorus losses in terrestrial ecosystems in China.

Future phosphorus (P) shortages could seriously affect terrestrial productivity and food security. We investigated the changes in topsoil available P (AP) and total P (TP) in China's forests, grasslands, paddy fields, and upland croplands during the 1980s-2010s based on substantial repeated soil P measurements (63,220 samples in the 1980s, 2000s, and 2010s) and machine learning techniques. Between the 1980s and 2010s, total soil AP stock increased with a small but significant rate of 0.13 kg P ha-1 year-1 , but total soil TP stock declined substantially (4.5 kg P ha-1 year-1 ) in the four ecosystems. We quantified the P budgets of soil-plant systems by harmonizing P fluxes from various sources for this period. Matching trends of soil contents over the decades with P budgets and fluxes, we found that the P-surplus in cultivated soils (especially in upland croplands) might be overestimated due to the great soil TP pool compared to fertilization and the substantial soil P losses through plant uptake and water erosion that offset the P additions. Our findings of P-deficit in China raise the alarm on the sustainability of future biomass production (especially in forests), highlight the urgency of P recycling in croplands, and emphasize the critical role of country-level basic data in guiding sound policies to tackle the global P crises.

Parallel two-photon lithography achieving uniform sub-200†nm features with thousands of individually controlled foci.

The limited throughput of nano-scale laser lithography has been the bottleneck for its industrial applications. Although using multiple laser foci to parallelize the lithography process is an effective and straightforward strategy to improve rate, most conventional multi-focus methods are plagued by non-uniform laser intensity distribution due to the lack of individual control for each focus, which greatly hinders the nano-scale precision. In this paper, we present a highly uniform parallel two-photon lithography method based on a digital mirror device (DMD) and microlens array (MLA), which allows the generation of thousands of femtosecond (fs) laser foci with individual on-off switching and intensity-tuning capability. In the experiments, we generated a 1,600-laser focus array for parallel fabrication. Notably, the intensity uniformity of the focus array reached 97.7%, where the intensity-tuning precision for each focus reached 0.83%. A uniform dot array structure was fabricated to demonstrate parallel fabrication of sub-diffraction limit features, i.e., below 1/4 λ or 200 nm. The multi-focus lithography method has the potential of realizing rapid fabrication of sub-diffraction, arbitrarily complex, and large-scale 3D structures with three orders of magnitude higher fabrication rate.

Deep accumulation of soluble organic nitrogen after land-use conversion from woodlands to orchards in a subtropical hilly region.

Accumulation of soluble organic nitrogen (SON) in soil poses a significant threat to groundwater quality and plays an important role in regulating the global nitrogen cycle; however, most related studies have focused only on the upper 100-cm soil layers. Surface land-use management and soil properties may affect the vertical distribution of SON; however, their influence is poorly understood in deep soil layers. Therefore, this study assessed the response of SON concentration, pattern, and storage in deep regoliths to land-use conversion from woodlands to orchards in a subtropical hilly region. Our results showed that the SON stocks of the entire soil profile (up to 19.5 m) ranged from 254.5 kg N ha-1 to 664.1 kg N ha-1. Land-use conversion not only reshaped the distribution pattern of SON, but also resulted in substantial accumulation of SON at the 0-200 cm soil profile in the orchards compared to that in the woodlands (124.1 vs 190.5 kg N ha-1). Land-use conversion also altered the SON/total dissolved nitrogen ratio throughout the regolith profile, resulting in a relatively low (<50 %) ratio in orchard soils below 200 cm. Overall, 76.8 % of SON (338.4 ± 162.0 kg N ha-1) was stored in the layers from 100 cm below the surface to the bedrock. Regolith depth (r = -0.52 and p < 0.05) was found to be significantly correlated with SON concentration, explaining 17.8 % of the variation in SON, followed by total nitrogen (14.4 %), total organic carbon/total nitrogen ratio (10.1 %), and bulk density (9.3 %). This study provides insights into the estimation of terrestrial nitrogen and guidance for mitigation of groundwater contamination risk due to deep accumulation of SON.

Soil acidification and loss of base cations in a subtropical agricultural watershed.

Soil acidification along with base cations loss degrades soil quality and is a major environmental problem, especially in agroecosystems with extensive nitrogen (N) fertilization. So far, the rates of proton (H+) production and real soil acidification (loss of base cations) remain unclear in subtropical agricultural watersheds. To assess the current status and future risk of soil acidification in subtropical red soil region of China, a two-year monitoring was conducted in a typical agricultural watershed with upland, paddy fields, and orchards where high N fertilizers are applied (320 kg N ha-1 yr-1). H+ production, neutralization and base cations losses were quantified based on the inputs (rainwater, inflow of water, and fertilizer) and outputs (outflow of water, groundwater drainage, and plant uptake) of major elements (K+, Ca2+, Na+, Mg2+, Al3+, NH4+, NO3-, SO42-, Cl-, and H+). The result showed that total H+ production in the watershed was 5152 molc ha-1 yr-1. N transformation was the most important H+ source (68%), followed by excess plant uptake of cations (25%) and H+ deposition (7%). Base cations exchange and weathering of minerals (3842 molc ha-1 yr-1) dominated H+ neutralization, followed by SO42- adsorption (1081 molc ha-1 yr-1), while H+ and Al3+ leaching amounted to 431 molc ha-1 yr-1, only. These results state clearly that despite significant soil acidification, the acidification of surface waters is minor, implying that soils have buffered substantially the net H+ addition. As a result of soil buffering, there was abundant loss of base cations, whose rate is significantly higher than the previously reported weathering rate of minerals in red soils (3842 vs 230-1080 molc ha-1 yr-1). This suggests that the pool of exchangeable base cations is being depleted in the watershed, increasing the vulnerability of the watershed, and posing a serious threat to future recovery of soils from acidification.

Cell orientation characteristics of the natural combs of honey bee colonies.

The cell orientation characteristics of the natural combs of honey bees have received much research attention. Although natural combs have been shown to be composed of cells with three orientations-vertical, intermediate (oblique), and horizontal-the proportion of comb cells in these three orientations varies. Knowledge of the comb-building preferences of honey bees is essential for the installation of wax comb foundations, and clarification of the cell orientation characteristics of natural honey bee combs is important for beekeeping. The purpose of this study was to determine the cell orientation characteristics of natural combs of Eastern honey bees (Apis cerana cerana) and Western honey bees (Apis mellifera ligustica). Newly built combs were used to measure the orientation of hexagonal cells and calculate the proportion of cells in different orientations relative to the total number of cells. The number of eggs laid by queens in the cells of different orientations was also determined. The orientation of cells in the natural combs of Eastern and Western honey bees was determined based on the value of the minimum included angle between the pair of parallel cell walls and a vertical line connecting the top and bottom bars of the movable frame in the geometric plane of the comb: 0°≤θ≤10°, 10°<θ≤20°, and 20°<θ≤30° for vertical, intermediate, and horizontal orientations, respectively. Natural combs were composed of cells with at least one orientation (vertical or horizontal), two orientations (vertical + intermediate (oblique) or vertical + horizontal), or three orientations (vertical + intermediate + horizontal), and the proportions of combs with the three aforementioned configurations differed. Both Eastern honey bees and Western honey bees preferred building combs with cells in a vertical orientation. Queens showed no clear preference for laying eggs in cells of specific orientations. The results of this study provide new insight that could aid the production and cutting of wax comb foundations of Eastern and Western honey bees. Our study highlights the importance of installing wax comb foundations compatible with the comb-building preferences of bees.

Discovery of a novel and potent inhibitor with differential species-specific effects against NLRP3 and AIM2 inflammasome-dependent pyroptosis.

The NLRP3 inflammasome, which regulated a proinflammatory programmed cell death form termed pyroptosis, is involved in the pathological process of various human diseases, such as multiple sclerosis, type 2 diabetes, and gout. Thus, compounds inhibiting activation of the NLRP3 inflammasome can be promising treatments for these diseases. In this study, we conducted a phenotypic screening against NLRP3-dependent pyroptosis and discovered the hit compound 1, which showed moderate antipyroptotic activity. Chemistry efforts to improve potency of 1 resulted in a novel compound 59 (J114), which exhibited a half-maximal inhibitory concentration (IC50) of 0.077 ± 0.008 µM against cell pyroptosis. Interestingly, unlike all pyroptosis inhibitors currently reported, the activity of J114 showed significant differences in human- and mouse-derived cells. The IC50 of J114-mediated inhibition of IL-1ß secretion by human THP-1 macrophages was 0.098 µM, which was nearly 150-fold and 500-fold more potent than that of J774A.1 (14.62 µM) and bone marrow-derived macrophages (BMDMs) (48.98 µM), respectively. Further studies showed that J114 displayed remarkable inhibitory activity against NLRP3- and AIM2-but not NLRC4-dependent activation of caspase-1 and the release of IL-1ß in human THP-1 macrophages. Mechanistically, J114 disturbed the interaction of NLRP3 or AIM2 with the adaptor protein ASC and inhibited ASC oligomerization. Overall, our study identified a unique molecule that inhibits NLRP3 and AIM2 inflammasome activation and has species differences, which is worthy of further research to understand the differential regulation of the NLRP3 and AIM2 inflammasomes in humans and mice.

Nitrate runoff loss and source apportionment in a typical subtropical agricultural watershed.

Nitrate (NO3-) loss and enrichment in water bodies caused by fertilization are a major environmental problem in agricultural areas. However, the quantitative contribution of different NO3- sources, especially chemical fertilizers (CF) and soil organic nitrogen (SON), to NO3- runoff loss remains unclear. In this study, a systematic investigation of NO3- runoff and its sources was conducted in a subtropical agricultural watershed located in Yujiang County, Jiangxi Province, China. A semi-monthly sampling was performed at the inlet and outlet from March 2018 to February 2019. Hydrochemical and dual NO3- isotope (15 N and 18O) approaches were combined to estimate the NO3- runoff loss and quantify the contribution of different sources with a Bayesian isotope mixing model. Source apportionment by Stable Isotope Analysis in R (SIAR) suggested that NO3- in runoff was mainly derived from nitrification of ammonium (NH4+) mineralized from SON (37-52%) and manure/sewage (M&S) (25-47%), while the contribution of CF was relatively small (14-25%). The contribution of various sources showed seasonal variations, with a greater contribution of CF in the wet growing season (March to August). Compared with the inlet which contributed 37-40% to runoff NO3-, SON contributed more at the outlet (49-52%). Denitrification in the runoff was small and appeared to be confined to the dry season (September to February), with an estimated NO3- loss of 2.73 kg N ha-1. The net NO3- runoff loss of the watershed was 34.5 kg N ha-1 yr-1, accounting for 15% of the annual fertilization rate (229 kg N ha-1 yr-1). Besides M&S (22%), fertilization and remineralization of SON (CF + SON) were the main sources for the NO3- runoff loss (78%), suggesting accelerated nitrification of NH4+ from CF (24%) and SON mineralization (54%). Our study indicates that NO3- runoff loss in subtropical agricultural watersheds is dominated by nonpoint source pollution from fertilization. SON played a more important role than CF. Besides, the contribution of sewage should not be neglected. Our data suggest that a combination of more rational fertilizer N application (CF), better management of SON, and better treatment of domestic sewage could alleviate NO3- pollution in subtropical China.

Seasonal dynamics of soil pH and N transformation as affected by N fertilization in subtropical China: An in situ 15N labeling study.

Nitrogen (N)-induced soil acidification has received much attention worldwide. Nitrification and soil N mineralization are two key N cycle processes that affect soil acidification. However, the seasonal dynamics of soil pH under their combined influence is unclear. We studied the effect of N fertilization on soil pH and N transformations using 15N tracing in field lysimeters with soils developed from different parent materials (Quaternary red clay, sandstone, and basalt). Maize was planted with 200 kg N ha-1 yr-115N-labeled urea addition. During 7-45 days after fertilization, proton (H+) production due to nitrification of fertilizer N, nitrate (NO3-) leaching, and plant uptake exceeded H+ consumption by base cations mobilization and leaching, resulting in a significant soil pH decline. When nitrification activity decreased (after 45 days), due to exhausted ammonium (NH4+) availability, soil pH rose again. During the fallow period, acid neutralization due to base cation mobilization, and ammonification of soil organic N (SON) offset H+ production caused by nitrification of mineralized SON, leading to a sustained rise in soil pH. After the one-year experiment, no significant soil pH decrease was observed in any of the soils. Parent material had little effect on the seasonal dynamics of soil acidification, which appeared to be controlled by fertilization, environmental factors (temperature and moisture), and plant uptake. In subtropical regions, monitoring of soil pH on an annual basis may mask the effect of N fertilization on soil acidification.

Evaluating and Comparing the Natural Cell Structure and Dimensions of Honey Bee Comb Cells of Chinese Bee, Apis cerana cerana (Hymenoptera: Apidae) and Italian Bee, Apis mellifera ligustica (Hymenoptera: Apidae).

The hexagonal structure of the honey bee comb cell has been the source of many studies attempting to understand its structure and function. In the storage area of the comb, only honey is stored and no brood is reared. We predicted that honey bees may construct different hexagonal cells for brood rearing and honey storage. We used quantitative analyses to evaluate the structure and function of the natural comb cell in the Chinese bee, Apis cerana cerana and the Italian bee, A. mellifera ligustica. We made cell molds using a crystal glue solution and measured the structure and inclination of cells. We found that the comb cells of A. c. cerana had both upward-sloping and downward-sloping cells; while the A. m. ligustica cells all tilted upwards. Interestingly, the cells did not conform to the regular hexagonal prism structure and showed irregular diameter sizes. In both species, comb cells also were differentiated into worker, drone and honey cells, differing in their diameter and depth. This study revealed unique differences in the structure and function of comb cells and showed that honey bees design their cells with precise engineering to increase storage capacity, and to create adequate growing room for their brood.

Deep Nitrate Accumulation in a Highly Weathered Subtropical Critical Zone Depends on the Regolith Structure and Planting Year.

Nitrate accumulated deep (>100 cm) in the regolith (soil and saprolite) threatens groundwater quality, but most studies focus only on nitrate nearer the surface (<100 cm). Surface soil management versus regolith interactions affect deep nitrate leaching, but their combined impact remains unclear. This study measured how deep nitrate accumulation was affected by crop practices including orchard/cropland planting years, regolith structure, and soil properties in highly weathered subtropical red soils. Deep nitrate storage varied from 43.6 to 1116.3 kg ha-1. Regolith thickness was positively correlated with nitrate storage (R2 = 0.43, p < 0.05). Reticulated red clay (110-838 cm) had 81% of the accumulated nitrate and overlapped with 79% of the nitrate accumulation layer. All of the nitrate accumulation parameters (except for peak depth (PD)) generally increased with the planting years. The difference in peak nitrate concentration (9.0-20.0 mg kg-1) with planting year gradient (3-58 years) varied by 2.2 times, and the difference in nitrate storage (43.6-425.7 kg ha-1) varied by 9.8 times. Texture and pH explain 41.6% of the variation in nitrate concentration. As soil management practices interact with deeper regolith to control the spatial pattern of nitrate accumulation, vulnerable regions could be identified to avoid high accumulation.

Ultra-broadband high conversion efficiency optical parametric chirped-pulse amplification based on YCOB crystals.

We present a high efficiency and ultra-broadband optical parametric chirped-pulse amplification (OPCPA) system fully based on yttrium calcium oxyborate (YCOB) crystals. The OPCPA properties of YCOB at 808 nm are studied for both high gain and saturated amplification. The non-collinear angle is finely tuned to study the variation of gain spectrum at a certain phase-matching angle of YCOB crystals. After amplification by four YCOB crystals, a total signal gain of 0.9×109 is obtained and the FWHM spectral bandwidth is still over 100 nm. An amplified signal pulse of 182 mJ is achieved with pump energy of 440 mJ in the saturated amplification stage and the conversion efficiency is about 40%. After a four-grating compressor, a pulse duration of 20 fs is measured by a second-order autocorrelator.

Dynamic chromatic aberration pre-compensation scheme for ultrashort petawatt laser systems.

A novel chromatic aberration pre-compensation scheme for ultrashort petawatt laser systems was proposed. The pre-compensation scheme consists of a convex lens, group of concave lenses, and a spherical reflector combined with a conventional vacuum chamber. It provides a versatile method to accurately compensate the chromatic aberration of an entire laser system via controlling the amount of propagation time delay (PTD) induced by the compensator without changing the input and output beam size. A compensator, tailored based on the proposed scheme, was designed and experimentally evaluated for the Shen-Guang-II 5PW (SG-II 5PW) laser system at Shanghai Institute of Optics and Fine Mechanics (SIOM). The experimental results verified that chromatic aberration in the laser system was almost fully compensated: the size of laser beam focused by an f/2.42 off-axis parabolic mirror (OAP) was reduced tremendously from 32×18µm2to about 4×4µm2at full width at half maximum (FWHM). The proposed scheme provides the flexibility to accurately correct chromatic aberration in high-power laser systems within a wide dynamic range.

Intra-horizon differentiation of the bacterial community and its co-occurrence network in a typical Plinthic horizon.

Subsurface soil bacterial community composition and the controlling factors remain largely unknown, especially the micro-zone differentiation of community composition within a horizon. We studied a plinthic horizon to determine how different micro-zones in a horizon affect the bacterial community. The plinthic horizon is a net-like horizon characterized by the segregation of iron forms as shown by contrasting red matrix and white veins, which share common macro-environmental conditions such as climate and land use but differ only in physical and chemical compositions. The studied horizon is typical of the red soils of southeastern China and is an important layer in the red soil Critical Zone. The plinthite is considered to have been formed in the Quaternary and thus is a record of the paleo-environment. We evaluated the difference in the bacterial community composition between the red matrix and white veins and explored the possible assembly mechanisms of their co-occurrence patterns. Compared to the eutrophic environments of a red matrix, higher relative abundances of Acidobacteria and Nitrospirae were observed in the white veins. Similarly, more niches led to a higher density of bacterial co-occurrence patterns in the red matrix. The differences in the bacterial community composition and association networks are due to environmental selection, including the legacy of the paleoclimate that is represented by major element contents and contemporary hydrological properties that are mainly controlled by the soil texture. Our study shows that micro-zones even within a same plinthic horizon can provide different habitats and thus select for specific bacterial communities. Furthermore, this study could improve our understanding of the differentiation of bacterial communities among microenvironments caused by both historical and contemporary processes and help to predict how these communities may respond to future environmental changes.

Broadband main OPCPA amplifier at 808 nm wavelength in high deuterated DKDP crystals.

The optical aperture of ultrashort extreme intensity laser facilities, which reach 10 PW, will be beyond several hundred millimeters. DKDP is by now the only nonlinear crystal that can be grown to such diameter and used in the main optical parametric chirped-pulse amplification (OPCPA) amplifier of such a laser system. Here, at the signal wavelength of 808 nm for the first time, we experimentally present a broadband OPCPA system that consists of a pre-amplifier in BBO crystals and a main OPCPA amplifier in two 95% deuterated DKDP crystals. The final amplified spectrum bandwidth exceeds 50 nm, and a compressed pulse duration of 27 fs has been measured. The conversion efficiency of the main OPCPA amplifier reached 24%, and a net signal gain of 13 was obtained. For the high energy OPCPA amplifier, the influence due to partial absorption on the idler pulses in DKDP crystal is theoretically analyzed. The results indicate the potential utilization of high deuterated DKDP for the main OPCPA amplifiers in a multi-petawatt laser system at 808 nm wavelength.

[Spatial interpolation of soil organic matter using regression Kriging and geographically weighted regression Kriging].

Relative elevation and stream power index were selected as auxiliary variables based on correlation analysis for mapping soil organic matter. Geographically weighted regression Kriging (GWRK) and regression Kriging (RK) were used for spatial interpolation of soil organic matter and compared with ordinary Kriging (OK), which acts as a control. The results indicated that soil or- ganic matter was significantly positively correlated with relative elevation whilst it had a significantly negative correlation with stream power index. Semivariance analysis showed that both soil organic matter content and its residuals (including ordinary least square regression residual and GWR resi- dual) had strong spatial autocorrelation. Interpolation accuracies by different methods were esti- mated based on a data set of 98 validation samples. Results showed that the mean error (ME), mean absolute error (MAE) and root mean square error (RMSE) of RK were respectively 39.2%, 17.7% and 20.6% lower than the corresponding values of OK, with a relative-improvement (RI) of 20.63. GWRK showed a similar tendency, having its ME, MAE and RMSE to be respectively 60.6%, 23.7% and 27.6% lower than those of OK, with a RI of 59.79. Therefore, both RK and GWRK significantly improved the accuracy of OK interpolation of soil organic matter due to their in- corporation of auxiliary variables. In addition, GWRK performed obviously better than RK did in this study, and its improved performance should be attributed to the consideration of sample spatial locations.

A dual role for UVRAG in maintaining chromosomal stability independent of autophagy.

Autophagy defects have recently been associated with chromosomal instability, a hallmark of human cancer. However, the functional specificity and mechanism of action of autophagy-related factors in genome stability remain elusive. Here we report that UVRAG, an autophagic tumor suppressor, plays a dual role in chromosomal stability, surprisingly independent of autophagy. We establish that UVRAG promotes DNA double-strand-break repair by directly binding and activating DNA-PK in nonhomologous end joining. Disruption of UVRAG increases genetic instability and sensitivity of cells to irradiation. Furthermore, UVRAG was also found to be localized at centrosomes and physically associated with CEP63, an integral component of centrosomes. Disruption of the association of UVRAG with centrosomes causes centrosome instability and aneuploidy. UVRAG thus represents an autophagy-related molecular factor that also has a convergent role in patrolling both the structural integrity and proper segregation of chromosomes, which may confer autophagy-independent tumor suppressor activity.