New targets of nascent lymphatic vessels in ocular diseases.

Recent advancements in the field of endothelial markers of lymphatic vessels and lymphangiogenic factors have shed light on the association between several ocular diseases and ocular nascent lymphatic vessels. The immune privilege of corneal tissue typically limits the formation of lymphatic vessels in a healthy eye. However, vessels in the eyes can potentially undergo lymphangiogenesis and be conditionally activated. It is evident that nascent lymphatic vessels in the eyes contribute to various ocular pathologies. Conversely, lymphatic vessels are present in the corneal limbus, ciliary body, lacrimal glands, optic nerve sheaths, and extraocular muscles, while a lymphatic vasculature-like system exists in the choroid, that can potentially cause several ocular pathologies. Moreover, numerous studies indicate that many ocular diseases can influence or activate nascent lymphatic vessels, ultimately affecting patient prognosis. By understanding the mechanisms underlying the onset, development, and regression of ocular nascent lymphatic vessels, as well as exploring related research on ocular diseases, this article aims to offer novel perspectives for the treatment of such conditions.

Spatial distribution pattern and correlation of dominant species in the arbor layer at a 25 hm2 forest plot in Lushan Mountain, China.

To explore the spatial pattern of zonal tree species in the subtropical subalpine mountain area on Lushan Mountain, a 25 hm2 forest plot was established in Yangtianping area of Lushan Mountain following the technical specification of CTFS in 2021. We classified these species into evergreen conifer species, deciduous broad-leaved species and evergreen broad-leaved species based on their leaf shape and deciduous or not to analyze the spatial pattern of dominant species of different types by spatial point pattern method. The results showed that Pinus taiwanensis, Cornus kousa subsp. chinensis, Platycarya strobilacea, Castanea henryi, Quercus serrata, Cornus controversa, Eurya muricata, Litsea elongata, and Eurya hebeclados were dominant species. Among these species, P. taiwanensis was the constructive one. The spatial pattern of dominant species was clustered at a certain scale, and gradually became to randomly distribution with the increases of scales. Evergreen conifer species was independent with deci-duous broad-leaved species and evergreen broad-leaved species at small scales, but was negatively correlated with them at large scales. Deciduous broad-leaved species and evergreen broad-leaved species were obviously negatively correlated with each other. Deciduous broad-leaved species were positively correlated or independent with each other at small scales, but were negatively correlated with each other at large scales. Evergreen broad-leaved species were positively correlated at small scales, independent at medium scales, and negatively correlated with each other at large scales.

Urbanization reduces soil microbial network complexity and stability in the megacity of Shanghai.

Urbanization is altering the co-occurrence networks of ecological communities that are critical to maintaining ecosystem functions and services. Soil microbial communities play key roles in various ecosystem processes, but how soil microbial co-occurrence networks respond to urbanization is unclear. Here we analyzed co-occurrence networks in soil archaeal, bacterial, and fungal communities from 258 soil sampling sites across the megacity of Shanghai along large urbanization gradients. We found that topological features of microbial co-occurrence networks were strongly altered by urbanization. In particular, microbial communities in more urbanized land-use and highly impervious land cover had less connected and more isolated network structures. These structural variations were accompanied by the dominance of connectors and module hubs affiliated with the Ascomycota in fungi and Chloroflexi in bacteria, and there were greater losses in efficiency and connectivity in urbanized than in remnant land-use in simulated disturbances. Furthermore, even though soil properties (especially soil pH and organic carbon) were major factors shaping topological features of the microbial networks, urbanization still uniquely explained a proportion of the variability, particularly those describing network connections. These results demonstrate that urbanization has clear direct and indirect effects on microbial networks and provide novel insights into how urbanization alters soil microbial communities.

Altitudinal variations and seasonal dynamics of near-surface and soil temperatures in subtropical forests of Mt. Guanshan, Jiangxi Province, China.

Temperature lapse rate (TLR), measured as the degree of temperature change along an altitudinal gradient, is a key indicator of multiple ecological processes of mountain systems. Although many studies have examined temperature changes of open air or near-surface along altitudes, we know little about altitudinal variations of soil temperature, which play an important role in regulating growth and reproduction of organisms, as well as ecosystem nutrient cycling. Based on temperature data of near-surface (15 cm above ground) and soil layers (8 cm below ground) from 12 sampling sites of subtropical forest along an altitudinal gradient (300-1300 m) in Jiangxi Guan-shan National Nature Reserve from September 2018 to August 2021, we calculated the lapse rates of mean, maximum, and minimum temperatures, as well as accumulated temperatures by using simple linear regression for both near-surface and soil temperature. The seasonal dynamics of aforementioned variables were also evaluated. The results showed that there were large differences among mean, maximum, and minimum lapse rates for annual near-surface temperature, which were 0.38, 0.31 and 0.51 ℃·(100 m)-1, respectively. But little variation was documented for soil temperature which were 0.40, 0.38 and 0.42 ℃·(100 m)-1, respectively. The seasonal variations of temperature lapse rates for near-surface and soil layers were minor except for minimum temperature. The lapse rates of minimum temperature were deeper in spring and winter for near-surface and in spring and autumn for soil layers. For growing degree days (GDD), the accumulated temperature under both layers were negatively correlated with altitude, and the lapse rates of ≥5 ℃ were 163 ℃·d·(100 m)-1 for near-surface and 179 ℃·d·(100 m)-1 for soil. The ≥5 ℃ GDD in soil were about 15 days longer than that in near-surface at the same altitude. The results showed inconsistent patterns of altitudinal variations between near-surface and soil temperature. Soil temperature and its lapse rates had minor seasonal variations compared with the near-surface counterparts, which was related to the strong buffering capacity of soil.

Comprehensive characterization of three classes of Arabidopsis SWI/SNF chromatin remodelling complexes.

Although SWI/SNF chromatin remodelling complexes are known to regulate diverse biological functions in plants, the classification, compositions and functional mechanisms of the complexes remain to be determined. Here we comprehensively characterized SWI/SNF complexes by affinity purification and mass spectrometry in Arabidopsis thaliana, and found three classes of SWI/SNF complexes, which we termed BAS, SAS and MAS (BRM-, SYD- and MINU1/2-associated SWI/SNF complexes). By investigating multiple developmental phenotypes of SWI/SNF mutants, we found that three classes of SWI/SNF complexes have both overlapping and specific functions in regulating development. To investigate how the three classes of SWI/SNF complexes differentially regulate development, we mapped different SWI/SNF components on chromatin at the whole-genome level and determined their effects on chromatin accessibility. While all three classes of SWI/SNF complexes regulate chromatin accessibility at proximal promoter regions, SAS is a major SWI/SNF complex that is responsible for mediating chromatin accessibility at distal promoter regions and intergenic regions. Histone modifications are related to both the association of SWI/SNF complexes with chromatin and the SWI/SNF-dependent chromatin accessibility. Three classes of SWI/SNF-dependent accessibility may enable different sets of transcription factors to access chromatin. These findings lay a foundation for further investigation of the function of three classes of SWI/SNF complexes in plants.

Arabidopsis Trithorax histone methyltransferases are redundant in regulating development and DNA methylation.

Although the Trithorax histone methyltransferases ATX1-5 are known to regulate development and stress responses by catalyzing histone H3K4 methylation in Arabidopsis thaliana, it is unknown whether and how these histone methyltransferases affect DNA methylation. Here, we found that the redundant ATX1-5 proteins are not only required for plant development and viability but also for the regulation of DNA methylation. The expression and H3K4me3 levels of both RNA-directed DNA methylation (RdDM) genes (NRPE1, DCL3, IDN2, and IDP2) and active DNA demethylation genes (ROS1, DML2, and DML3) were downregulated in the atx1/2/4/5 mutant. Consistent with the facts that the active DNA demethylation pathway mediates DNA demethylation mainly at CG and CHG sites, and that the RdDM pathway mediates DNA methylation mainly at CHH sites, whole-genome DNA methylation analyses showed that hyper-CG and CHG DMRs in atx1/2/4/5 significantly overlapped with those in the DNA demethylation pathway mutant ros1 dml2 dml3 (rdd), and that hypo-CHH DMRs in atx1/2/4/5 significantly overlapped with those in the RdDM mutant nrpe1, suggesting that the ATX paralogues function redundantly to regulate DNA methylation by promoting H3K4me3 levels and expression levels of both RdDM genes and active DNA demethylation genes. Given that the ATX proteins function as catalytic subunits of COMPASS histone methyltransferase complexes, we also demonstrated that the COMPASS complex components function as a whole to regulate DNA methylation. This study reveals a previously uncharacterized mechanism underlying the regulation of DNA methylation.

AtHD2D, a plant-specific histone deacetylase involved in abscisic acid response and lateral root development.

In eukaryotes, histone acetylation levels directly regulate downstream gene expression. As a plant-specific histone deacetylase (HDAC), HD2D is involved in plant development and abiotic stress. However, the response of HD2D to drought stress and its interacting proteins, is still unclear. In this study, we analysed HD2D gene expression patterns in Arabidopsis, revealing that HD2D gene was highly expressed in roots and rosette leaves, but poorly expressed in other tissues such as stems, flowers, and young siliques. The HD2D gene expression was induced by d-mannitol. We investigated the responses to drought stress in the wild-type plant, HD2D overexpression lines, and hd2d mutants. HD2D-overexpressing lines showed abscisic acid (ABA) hypersensitivity and drought tolerance, and these phenotypes were not present in hd2d mutants. RNA-seq analysis revealed the transcriptome changes caused by HD2D under drought stress, and showed that HD2D responded to drought stress via the ABA signalling pathway. In addition, we demonstrated that CASEIN KINASE II (CKA4) directly interacted with HD2D. The phosphorylation of Ser residues on HD2D by CKA4 enhanced HD2D enzymatic activity. Furthermore, the phosphorylation of HD2D was shown to contribute to lateral root development and ABA sensing in Arabidopsis, but, these phenotypes could not be reproduced by the overexpression of Ser-phospho-null HD2D lines. Collectively, this study suggests that HD2D responded to drought stress by regulating the ABA signalling pathway, and the expression of drought stress-related genes. The regulatory mechanism of HD2D mediated by CKII phosphorylation provides new insights into the ABA response and lateral root development in Arabidopsis.

Characterization of an autonomous pathway complex that promotes flowering in Arabidopsis.

Although previous studies have identified several autonomous pathway components that are required for the promotion of flowering, little is known about how these components cooperate. Here, we identified an autonomous pathway complex (AuPC) containing both known components (FLD, LD and SDG26) and previously unknown components (EFL2, EFL4 and APRF1). Loss-of-function mutations of all of these components result in increased FLC expression and delayed flowering. The delayed-flowering phenotype is independent of photoperiod and can be overcome by vernalization, confirming that the complex specifically functions in the autonomous pathway. Chromatin immunoprecipitation combined with sequencing indicated that, in the AuPC mutants, the histone modifications (H3Ac, H3K4me3 and H3K36me3) associated with transcriptional activation are increased, and the histone modification (H3K27me3) associated with transcriptional repression is reduced, suggesting that the AuPC suppresses FLC expression at least partially by regulating these histone modifications. Moreover, we found that the AuPC component SDG26 associates with FLC chromatin via a previously uncharacterized DNA-binding domain and regulates FLC expression and flowering time independently of its histone methyltransferase activity. Together, these results provide a framework for understanding the molecular mechanism by which the autonomous pathway regulates flowering time.

[Species composition and community structure of a spruce-fir forest and a larch forest on the northern slope of Changbai Mountains, Northeast China].

Spruce-fir forest is the best protected forest vegetation, while larch forest is intrazonal vegetation on the northern slope of Changbai Mountains. To further understand their species composition and community structure, we established a 4 hm2 forest permanent plot in each of these two forests in 2010. All free-standing plant species with DBH (diameter at breast height) ≥ 1 cm were mapped, tagged, and identified to species. The results showed that there were 9257 stems belonging to 8640 genotype individuals, 22 species, 6 genera and 12 families in the spruce-fir forest plot, while 4060 stems belonging to 3696 genotype individuals, 22 species, 8 genera and 16 families in the larch forest plot. Species composition in the two plots was very similar. Most of the species belonged to the Changbai Mountains plant flora. The analysis of species' importance values showed that there were dominant species in both communities. The spruce-fir forest was dominated by Abies nephrolepis and Larix olgensis, whose importance values accounted for 38.7% and 23.9% of the sum of importance values over all species in the plot, respectively. The larch forest was dominated solely by L. olgensis, whose importance value accounted for 61.9% of the sum of importance values over all species in the plot. Both forests were in good condition of regeneration and showed a reversed 'J' type in tree size distributions, at community level. However, different species showed different shapes in size distribution in the two forests. A. nephrolepis showed a reversed 'J' type size distribution in the spruce-fir forest, while L. olgensis with DBH ≥ 10 cm showed a hump-shaped distribution in the larch forest. Spatial distribution patterns of the main species changed differently with size class and spatial scales. Common species had different spatial distribution patterns in the two plots.

[Woody plant species composition and community structure in residual fragments of broad-leaved Korean pine mixed forests in Changbai Mountains area].

The broad-leaved Korean pine mixed forest represents the typical vegetation type of the eastern mountain area in Northeast China. However, due to the interference of human activities, the natural broad-leaved Korean pine forest only distributes in some residual fragments with unequal areas in Changbai Mountains and Small Hinggan Mountains. To compare and analyze the similarities and differences of broad-leaved Korean pine mixed forests in the different areas, we established six forest plots following the field protocol of the 50 hm2 forest plot in Panama (Barro Colorado Island, BCI) in 2012 in Changbai Mountain National Nature Reserve in Jilin Province and the eastern mountain area in Liaoning Province. All free-standing plant species with DBH (diameter at breast height) > or = 1 cm were mapped, tagged and identified to species. The results showed that there were 69 woody species in the six plots, comprising 42 genera and24 families. Aceraceae was the most species-rich family in all six plots. Most species belonged to the plant type of North Temperate Zone, with a minor subtropical plant species component. The statistics of species abundance, basal area, mean DBH, and importance value showed that there were obviously dominant species in each community. The DBH distribution of all individuals showed a reversed "J" type. However, the percentage of individuals in small size-class and large size-class varied in the six communities, which indicated that these communities were at different successional stages. Ranked by the importance value, the DBH distribution of the top three species in the six plots showed four distribution types: reversed "J" distribution, reversed "L" distribution, unimodal distribution, and partial peak distribution. Spatial distribution patterns of the main species in the six plots changed differently with species and size-class, and the distribution patterns of the same species varied in the different plots.

[Short-term death dynamics of trees in natural secondary poplar-birch forest in Changbai Mountains of Northeast China].

Taking the 5 hm2 sampling plot in the natural secondary poplar-birch forest in Changbai Mountains as test object, and based on the two census data in 2005 and 2010, an analysis was made on the main tree species composition and quantity, size class distribution of dead individuals, and regeneration characteristics of the main tree species in different habitat types of the plot in 2005-2010. In the five years, the species number of the individuals with DBH> or = 1 cm increased from 46 to 47, among which, 3 species were newly appeared, and 2 species were disappeared. The number of the individuals changed from 16509 to 15027, among which, 2150 individuals died, accounting for 13% of the whole individuals in 2005, and 668 individuals were newly increased. The basal area of the trees increased from 28.79 m2.m-2 to 30.55 m2.m-2, with that of 41 species increased while that of 6 species decreased. The decrease of the basal area of Betula platyphylla and Populus davidiana accounted for 72.3% of the total decrease. Small individuals had higher mortality, as compared with large ones, and the mortality of the individuals with DBH<5 cm occupied 65% of the total. B. platyphylla and P. davidiana contributed most in the dead individuals with large DBH. No difference was observed in the tree mortality among different habitat types, but the mortality of the individuals with different size classes showed greater variation.

Development of intelligential apparatus of rehabilitation for disablement of limb.

In this paper Intelligentized multi-functional limb treatment and rehabilitation based on computer-controlled system, is introduced. This system mainly used for treatment and rehabilitation in the disablement of limb. The range speed and training time can be automatically controlled. Training parameter and result can be monitored on computer. The apparatus has the advantages of high reliability, easy operation and compact design. It is a new kind of intelligent limb rehabilitation.