Divergent mechanisms of reduced growth performance in Betula ermanii saplings from high-altitude and low-latitude range edges.

The reduced growth performance of individuals from range edges is a common phenomenon in various taxa, and considered to be an evolutionary factor that limits the species' range. However, most studies did not distinguish between two mechanisms that can lead to this reduction: genetic load and adaptive selection to harsh conditions. To address this lack of understanding, we investigated the climatic and genetic factors underlying the growth performance of Betula ermanii saplings transplanted from 11 populations including high-altitude edge and low-latitude edge population. We estimated the climatic position of the populations within the overall B. ermanii's distribution, and the genetic composition and diversity using restriction-site associated DNA sequencing, and measured survival, growth rates and individual size of the saplings. The high-altitude edge population (APW) was located below the 95% significance interval for the mean annual temperature range, but did not show any distinctive genetic characteristics. In contrast, the low-latitude edge population (SHK) exhibited a high level of linkage disequilibrium, low genetic diversity, a distinct genetic composition from the other populations, and a high relatedness coefficient. Both APW and SHK saplings displayed lower survival rates, heights and diameters, while SHK saplings also exhibited lower growth rates than the other populations' saplings. The low heights and diameters of APW saplings was likely the result of adaptive selection to harsh conditions, while the low survival and growth rates of SHK saplings was likely the result of genetic load. Our findings shed light on the mechanisms underlying the reduced growth performance of range-edge populations.

Gross primary production of dwarf bamboo, Sasa senanensis, in a mature beech forest with a substantial gap-mosaic structure.

Forest understory plays an important role in the gross primary production (GPP) of some forest ecosystems. However, differences in understory GPP caused by obviously different overstory canopy structure have not been taken into consideration in previous studies, thus potentially over- or underestimating understory GPP. To estimate the understory GPP more accurately, we separated a forest into "canopy area", with closed-overstory canopy, and "gap area", with open-overstory canopy. The study was conducted in a mature deciduous forest dominated by beech and with an understory dominated by dwarf bamboo, Sasa senanensis. We measured S. senanensis GPP at the community scale (GPPSasa-community) using a static chamber system that covered the aboveground part of the plants and then upscaled it to the ecosystem scale (GPPSasa-ecosystem) by considering the proportions of canopy and gap areas within the forest. GPPSasa-community was 192 g C m-2 year-1 in the canopy area and 699 g C m-2 year-1 in the gap area. The large difference likely occurred because the photosynthetic ability and biomass of the S. senanensis community differed strongly between the two areas. The seasonal dynamics of GPPSasa-community also differed between the areas. The 10-day cumulative GPPSasa-community peaked from July to August in the gap area, whereas there was no clear peak of GPPSasa-community in the canopy area. Multiple linear regressions showed that light intensity and biomass were significant predictors of GPPSasa-community in the canopy area, whereas air temperature and biomass were significant predictors of GPPSasa-community in the gap area. GPPSasa-ecosystem during growing season in 2019 was 3.74 t C ha-1 year-1, which contributed between 16.37 and 19.85% of the entire forest ecosystem GPP. This study highlights the need to consider differences in overstory structure for the accurate estimation of understory GPP.

The neuronal protein Neurexin directly interacts with the Scribble-Pix complex to stimulate F-actin assembly for synaptic vesicle clustering.

Synaptic vesicles (SVs) form distinct pools at synaptic terminals, and this well-regulated separation is necessary for normal neurotransmission. However, how the SV cluster, in particular synaptic compartments, maintains normal neurotransmitter release remains a mystery. The presynaptic protein Neurexin (NRX) plays a significant role in synaptic architecture and function, and some evidence suggests that NRX is associated with neurological disorders, including autism spectrum disorders. However, the role of NRX in SV clustering is unclear. Here, using the neuromuscular junction at the 2-3 instar stages of Drosophila larvae as a model and biochemical imaging and electrophysiology techniques, we demonstrate that Drosophila NRX (DNRX) plays critical roles in regulating synaptic terminal clustering and release of SVs. We found that DNRX controls the terminal clustering and release of SVs by stimulating presynaptic F-actin. Furthermore, our results indicate that DNRX functions through the scaffold protein Scribble and the GEF protein DPix to activate the small GTPase Ras-related C3 Botulinum toxin substrate 1 (Rac1). We observed a direct interaction between the C-terminal PDZ-binding motif of DNRX and the PDZ domains of Scribble and that Scribble bridges DNRX to DPix, forming a DNRX-Scribble-DPix complex that activates Rac1 and subsequently stimulates presynaptic F-actin assembly and SV clustering. Taken together, our work provides important insights into the function of DNRX in regulating SV clustering, which could help inform further research into pathological neurexin-mediated mechanisms in neurological disorders such as autism.

Response of stomatal density and size in Betula ermanii to contrasting climate conditions: The contributions of genetic and environmental factors.

As plant distribution and performance are determined by both environmental and genetic factors, clarifying the contribution of these two factors is a key for understanding plant adaptation and predicting their distribution under ongoing global warming. Betula ermanii is an ideal species for such research because of its wide distribution across diverse environments. Stomatal density and size are crucial traits that plants undergo changes in to adapt to different environments as these traits directly influence plant photosynthesis and transpiration. In this study, we conducted a multi-location common garden experiment using B. ermanii to (1) clarify the contribution of both environmental and genetic factors to the variation in stomatal density and size of B. ermanii, (2) demonstrate the differences in the plasticity of stomatal density and size among B. ermanii populations, and (3) understand how stomatal density and size of B. ermanii would respond to increased temperature and changing precipitation patterns. Genetic factors played a more significant role in stomatal size than environmental factors, suggesting that B. ermanii struggles to adjust its stomatal size in response to a changing environment. Our results also revealed a positive correlation between stomatal size plasticity and original habitat suitability, indicating that in B. ermanii populations in harsh environments exhibit lower adaptability to environmental shifts. Although stomatal density and size of B. ermanii showed the significant responses to increased temperature and shifting precipitation patterns, the response ranges of stomatal density and size to the environmental factors varied among populations. Our findings highlighted the interplay between genetic and environmental factors in determining the intraspecific variation in stomatal density and size in B. ermanii. This indicated that certain populations of B. ermanii exhibit limited stomatal plasticity and adaptability, which could directly affect photosynthesis and transpiration, suggesting potential population-specific fitness implications for B. ermanii under future climate change.

Spatial variation in forest soil respiration: A systematic review of field observations at the global scale.

As it is responsible for the second largest CO2 flux in the terrestrial ecosystem, the accurate estimation and prediction of soil respiration (SR) are necessary, especially for forest ecosystems, which are a major contributor to the total terrestrial SR. Spatial variation is one of the challenges affecting the accurate estimation and prediction of forest SR in ecosystems. Although a number of studies have examined spatial variation in SR within individual forests, the magnitude and patterns of spatial variation in SR within forest ecosystems (CV of SR [%]) remain unexplored at the global scale. In this study, we collected 94 field observation studies to demonstrate the range and pattern of the CV of SR, and to clarify the controlling factors. Through our analysis, the CV of SR was found to range from 1.8 % to 89.3 % on the global scale; it was highest in the equatorial zone (39.0 % ± 13.8 %) and followed by the warm temperate zone (32.6 ± 14.5 %) and the snow zone (30.0 % ± 16.3 %). There was a significant negative correlation between the CV of SR and soil water content, bulk density, fine root biomass, and elevation at both the global scale and in each climatic zone (P < 0.01). Other factors such as total nitrogen content, mean of diameter at breast height, slope, etc., were also significantly correlated with the CV of SR, but the correlation was different among climatic zones. This study provides an overall perspective of the CV of SR by clarifying the range, patterns, and controlling factors at both the global scale and in each climatic zone. However, further research is needed, especially regarding the mechanisms between the CV of SR and its controlling factors.

[A multi-stage and multi-epitope vaccine against Mycobacterium tuberculosis based on an immunoinformatics approach].

Objectives To develop a multi-stage and multi-epitope vaccine, which consists of epitopes from the early secretory and latency-associated antigens of Mycobacterium tuberculosis (MTB). Methods The B-cell, cytotoxic T-lymphocyte (CTL) and helper T-lymphocyte (HTL) epitopes of 12 proteins were predicted using an immunoinformatics. The epitopes with antigenicity, without cytotoxicity and sensitization, were further screened to construct the multi-epitope vaccine. Furthermore, the proposed vaccine underwent physicochemical properties analysis and secondary structure prediction as well as 3D structure modeling, refinement and validation. Then the refined model was docked with TLR4. Finally, an immune simulation of the vaccine was carried out. Results The proposed vaccine, which consists of 12 B-cell, 11 CTL and 12 HTL epitopes, had a flexible and stable globular conformation as well as a thermostable and hydrophilic structure. A stable interaction of the vaccine with TLR4 was confirmed by molecular docking. The efficiency of the candidate vaccine to trigger effective cellular and humoral immune responses was assessed by immune simulation. Conclusion A multi-stage multi-epitope MTB vaccine construction strategy based on immunoinformatics is proposed, which is expected to prevent both active and latent MTB infection.

Clinical application of free/total PSA ratio in the diagnosis of prostate cancer in men over 50 years of age with total PSA levels of 2.0-25.0 ng ml-1 in Western China.

The goal of this study was to investigate the clinical application of free/total prostate-specific antigen (F/T PSA) ratio, considering the new broad serum total PSA (T-PSA) "gray zone" of 2.0-25.0 ng ml-1 in differential diagnosis of prostate cancer (PCa) and benign prostate diseases (BPD) in men over 50 years in Western China. A total of 1655 patients were included, 528 with PCa and 1127 with BPD. Serum T-PSA, free PSA (F-PSA), and F/T PSA ratio were analyzed. Receiver operating characteristic curves were used to assess the efficiency of PSA and F/T PSA ratio. There were 47.4% of cancer patients with T-PSA of 2.0-25.0 ng ml-1. When T-PSA was 2.0-4.0 ng ml-1, 4.0-10.0 ng ml-1, and 10.0-25.0 ng ml-1, the area under the curve (AUC) of F/T PSA ratio was 0.749, 0.769, and 0.761, respectively. The best AUC of F/T PSA ratio was 0.811 when T-PSA was 2.0-25.0 ng ml-1, with a specificity of 0.732, a sensitivity of 0.788, and an optimal cutoff value of 15.5%. The AUC of F/T PSA ratio in different age groups (50-59 years, 60-69 years, 70-79 years, and ≥80 years) was 0.767, 0.806, 0.815, and 0.833, respectively, and the best sensitivity (0.857) and specificity (0.802) were observed in patients over 80 years. The T-PSA trend was in accordance with the Gleason score, tumor node metastasis (TNM) stage, and American Joint Committee on Cancer prognosis group. Therefore, the F/T PSA ratio can facilitate the differential diagnosis of PCa and BPD in the broad T-PSA "gray zone". Serum T-PSA can be a Gleason score and prognostic indicator.

MoS2 decorated CdS hybrid heterojunction for enhanced photoelectrocatalytic performance under visible light irradiation.

Pervious photocatalysis application of nanostructured suspensions reveals high recombination rates of photogenerated electron-hole pairs, low recycling efficiency and secondary pollution problems. Herein, MoS2@CdS nanocomposites thin films on FTO (fluorine-doped tin oxide) substrates are fabricated using facile electrodeposition by decorating a layer of highly-active MoS2 cocatalyst on CdS film to optimize the interface modification. The hybrid film exhibits enhanced photoelectrocatalytic activity compared to pristine CdS film. The synthesized CdS exhibits a bandgap of 2.42 eV with the conduct band at ca. -0.25 V vs. RHE, while MoS2 reveals a bandgap of 1.73 eV with the valance band at ca. 1.59 V vs. RHE. The appropriate band alignment between the hybrid films favours the electrons transfer thus the charge recombination are suppressed. The MoS2@CdS film yields a highest photocurrent of 15.2 mA/cm2 at 0 V vs. Ag/AgCl under visible light illumination (λ ≧ 420 nm), exhibiting a 5.2 times enhancement as compared to that of CdS film (2.9 mA/cm2). The structural integration of MoS2 with CdS will be a promising strategy to develop a high-efficient and low-cost non-noble metal cocatalyst for solar energy conversion.