Microglial NLRP3 inflammasome-mediated neuroinflammation and therapeutic strategies in depression

Previous studies have demonstrated a bidirectional relationship between inflammation and depression.Activation of the nucleotide-binding oligomerization domain,leucine-rich repeat,and NLR family pyrin domain-containing 3(NLRP3)inflammasomes is closely related to the pathogenesis of various neurological diseases.In patients with major depressive disorder,NLRP3 inflammasome levels are significantly elevated.Understanding the role that NLRP3 inflammasome-mediated neuroinflammation plays in the pathogenesis of depression may be beneficial for future therapeutic strategies.In this review,we aimed to elucidate the mechanisms that lead to the activation of the NLRP3 inflammasome in depression as well as to provide insight into therapeutic strategies that target the NLRP3 inflammasome.Moreover,we outlined various therapeutic strategies that target the NLRP3 inflammasome,including NLRP3 inflammatory pathway inhibitors,natural compounds,and other therapeutic compounds that have been shown to be effective in treating depression.Additionally,we summarized the application of NLRP3 inflammasome inhibitors in clinical trials related to depression.Currently,there is a scarcity of clinical trials dedicated to investigating the applications of NLRP3 inflammasome inhibitors in depression treatment.The modulation of NLRP3 inflammasomes in microglia holds promise for the management of depression.Further investigations are necessary to ascertain the efficacy and safety of these therapeutic approaches as potential novel antidepressant treatments.

Influence of vegetation parameters on runoff and sediment characteristics in patterned Artemisia capillaris plots

Vegetation patterns are important in the regulation of earth surface hydrological processes in arid and semi-arid areas. Laboratory-simulated rainfall experiments were used at the State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Yangling, northwestern China, to quantify the effects of Artemisia capillaris patterns on runoff and soil loss. The quantitative relationships between runoff/sediment yield and vegetation parameters were also thoroughly analyzed using the path analysis method for identifying the reduction mechanism of vegetation on soil erosion. A simulated rainfall intensity of 90 mm/h was applied on a control plot without vegetation （Co） and on the other three different vegetation distribution patterns： a checkerboard pattern （CP）, a banded pattern perpendicular to the slope direction （BP）, and a single long strip parallel to the slope direction （LP）. Each patterned plot received two sets of experiments, i.e. intact plants and roots only, respectively. All treatments had three replicates. The results showed that all the three other different patterns （CP, BP and LP） of A. capillaris could effectively reduce the runoff and sediment yield. Compared with Co, the other three intact plant plots had a 12%-25% less runoff and 58%-92% less sediment. Roots contributed more to sediment reduction （46%-70%）, whereas shoots contributed more to runoff reduction （57%-81%）. BP and CP exhibited preferable controlling effects on soil erosion compared with LP. Path analysis indicated that root length density and plant number were key parameters influencing runoff rate, while root surface area density and root weight density were central indicators affecting sediment rate. The results indicated that an appropriate increase of sowing density has practical significance in conserving soil and water.

Fractal features of soil profiles under different land use patterns on the Loess Plateau, China

Fractal theory is becoming an increasingly useful tool to describe soil structure dynamics for a better understanding of the performance of soil systems. Changes in land use patterns significantly affect soil physical, chemical and biological properties. However, limited information is available on the fractal characteristics of deep soil layers under different land use patterns. In this study, the fractal dimensions of particle size distribution（PSD） and micro-aggregates in the 0–500 cm soil profile and soil anti-erodibility in the 0–10 cm soil profile for 10 typical land use patterns were investigated in the Zhifanggou Watershed on the Loess Plateau, China. The 10 typical land use patterns were： slope cropland, two terraced croplands, check-dam cropland, woodland, two shrublands, orchard, artificial and natural grasslands. The results showed that the fractal dimensions of PSD and micro-aggregates were all significantly influenced by soil depths, land use patterns and their interaction. The plantations of shrubland, woodland and natural grassland increased the amount of larger micro-aggregates, and decreased the fractal dimensions of micro-aggregates in the 0–40 cm soil profile. And they also improved the aggregate state and aggregate degree and decreased dispersion rate in the 0–10 cm soil profile. The results indicated that fractal theory can be used to characterize soil structure under different land use patterns and fractal dimensions of micro-aggregates were more effective in this regard. The natural grassland may be the best choice for improving soil structure in the study area.

Soil legacy effects and plant-soil feedback contribution to secondary succession processes

Secondary succession is the process by which a community develops into a climax community over time.However,knowledge on the mechanisms,relating to soil legacy effects(soil chemistry and enzyme activity)and plant-soil feedback(PSF),driving community succession remains limited.In this work,we examined the PSF associated with three succession stage species through a 2-year greenhouse experiment.Setaria viridis,Stipa bungeana,and Bothriochloa ischemum were selected to represent dominant and representative early-,mid-,and late-successional stage species,respectively,of semiarid grasslands on the Loess Plateau.In response to the different soil origin,the shoot biomass of early-,mid-,and late-species were all higher when grown in their own soil than in other species’soils,which indicated that the PSF of three species were positive.Over two growth periods,the early-species experienced a negative PSF,but the mid-and late-species experienced negative,neutral and positive PSF in the soil of early-,mid-and late-species,respectively.Our study demonstrates that soil legacy effects and PSF have a significant impact on community succession processes.

Invasibility and recoverability of a plant community following invasion depend on its successional stages

Exotic species invasion represent important causes of harming the structure,function,and ecological environment in ecosystems.Yet,knowledge remains limited on the invasibility(invasion advantage of exotic species)and recoverability(recovery ability of native species)of a plant community following invasion depend on its successional stages.We selected three grasses of Setaria viridis,Artemisia gmelinii,and Bothriochloa ischemum representing early(E),middle(M),and late(L)successional species,respectively.Meanwhile,the grasses of Panicum virgatum was selected to represent exotic species(invasion species).Three types of soil were collected to treat the three E,M,and L successional species,and one type of soil was collected to treat the exotic species.We compared the performance of the three native plant species and one exotic species grown in their“own”and“other”soils in a 2-year greenhouse experiment.Our study showed that exotic species performed better in soils of E and M successional species than in the soil of L successional species.After exotic species removed,E and M successional species exhibited poor growth in the soil of exotic species,while that of L successional species performed poor in field exotic species soils,but performed better in soils disturbed by exotic species.Our study demonstrated that the invasibility and recoverability of native plant communities changed with vegetation succession.

Interactions between soil conservation and dryland farming of heterogeneously eroding areas in Loess Hills,China

The unidirectional impacts of soil conservation on dryland farming and local livelihood have been well studied.However,there are gaps in literature regarding the interactions among factors,such as labor force and financial capital,in response to soil conservation,as well as the influence of such interactions on the relationships between environmental projects and agricultural development.By combining the Chinese Soil Loss Equation(CSLE)model and statistical analyses,this study investigated the spatiotemporal characteristics of soil erosion while also identifying the controlling factors that affect crop and livestock farming.The aim was to reveal how these factors interacted to influence agriculture in two case study areas between 2000 and 2017.The results showed that soil erosion substantially declined as a consequence of soil conservation,while the output from crop farming increased,indicating that there was a synergy between soil conservation and dryland farming in both the districts,over time;and factors facilitating crop farming,such as labor force,agricultural machinery,and irrigation,appeared to exert an adverse effect on livestock farming in both areas,implying a tradeoff between livestock and crop farming in the context of programs such as the Grain for Green Program(GGP)in the Loess Hills.Such a tradeoff is a result of the competition for cropland and labor that exists due to grazing prohibition and rural-urban migration.Therefore,policy-related resolutions are required to address the land use conflicts and migration-related rural labor losing due to implementation of the GGP in the Loess Hills.

Species diversity and interspecific association in development sequence of Hippophae rhamnoides plantations in the Loess Hilly Region, China

Based on our field investigation,we analyzed the characteristics of species diversity and interspecific association at different development stages of Hippohae rhamnoides plantations.The results show that the species diversities of the shrub layer,grass layer and the whole community of the H.rhamnoides plantations all fluctuated in an“S”shape pattern.At different development stages,the species richness and diversity were higher in the grass layer than in the shrub layer.The shrub species diversity was lower on bare land,but increased gradually with development of the community.The shrub evenness index was higher in 13-year forest stand,while the grass diversity index was higher in the 3-year and 25-year plantations and lower in the 8-year plantation.The positive and negative absolute values of interspecific association between H.rhamonides and other principal species changed in a parabolic pattern.The significance level and intensity of interspecific association were lower or weaker in the13-year plantation,indicating that the species substitution rate slowed down,competition became less intense and community composition and its structure reached a relatively stable state.Therefore,to improve the ecological environment,priority should be given to the protection of the H.rhamnoides plantations younger than 13 years,while for those of 25 year plantations,moderate thinning should be made to promote their regeneration.

Effects of nitrogen addition on plant-soil-microbe stoichio-metry characteristics of different functional group species in Bothriochloa ischemum community

Nitrogen(N)deposition,the source of N input into terrestrial ecosystems,is exhibiting an increasingly serious impact on the biogeochemical cycle and functional stability of ecosystems.Grasslands are an important component of terrestrial ecosystems and play a key role in maintaining terrestrial ecosystem balance.Therefore,it is critical to understand the effects of nitrogen addition on grassland ecosystems.We conducted gradientN addition experiments(0,3,6,and 9 g N m^(-2)2 y^(-1))for threeyears ingrassland communities with similar site conditions.We utilized four typical herbaceous plants,including the dominant species Bothriochloa ischemum(B.ischemum)and companion species Stipa bungeana(S.bungeana),Artemisia gmelinii(A.gmelinii),and Cleistogenes squarrosa(C.squarrosa),to explore how different plant-soil-microbe systems respond to N addition.Stoichiometric homeostasis analysis demonstrated that both plants and microbes were strictly homeostatic.However,the companion species were found to be more susceptible to P dominant species.Furthermore,aggravated overlap in stoichiometric niches between plant species were observed at the N6 and N9 levels.Vector analysis indicated that the vector angle was>45°regardlessof plant species and N levels,suggesting that there was a strong Plimitation in the rhizosphere microbial community.Variation partitioning analysis revealed that the Composite roots exhibited a greater effect(explaining 34.7% of the variation)on the rhizosphere microbes than on the Gramineae,indicating that there may be more intense nutrient competition in its rhizosphere.Ingeneral,the effects of N addition on species were different a cross functional groups,with a significant positive effect on the Gramineae(B.ischemum,S.bungeana,and C.squarrosa)and a significant negative effecton the Compositae(A.gmelinii),which should be fully considered in the future ecological management and restoration.

Long-term warming does not affect soil ecoenzyme activity and original microbial nutrient limitation on the Qinghai-Tibet Plateau

Microbes play an important role in the carbon cycle and nutrient flow of the soil ecosystem.However,the response of microbial activities to long-term warming over decades is poorly understood.To determine how warming changes ecoenzyme activity and microbial nutrient limitation,we conducted a long-term,21 years,experiment,on the Qinghai–Tibet Plateau.We selected typical grass-and shrub-covered plots,used fiberglass open-top chambers(OTCs)to raise the temperature,conducted soil sampling at different depths,studied the response of nutrient-acquiring enzyme activity and stoichiometry,and conducted vector analysis of stoichiometry.Our results showed that long-term warming did not have a notable effect on the activity of nutrient-acquiring enzymes or enzymatic stoichiometry.However,Spearman correlation analysis indicated a significant and positive correlation between ecoenzyme activity and the available nutrients and microbial biomass in soil.Vector analysis of stoichiometry showed phosphorus limitation for all soil microbes at different depths,regardless of whether the soil experienced warming.These changes in enzymatic stoichiometry and vector analysis suggested that microbial nutrient limitation was not alleviated substantially by long-term warming,and warming did not considerably affect the stratification of microbial nutrient limitation.Our research has also shown that long-term warming does not significantly change soil ecoenzyme activity and original microbial nutrient limitation at different soil depths within the OTUsʼimpact range.These results could help improve understanding of microbial thermal acclimation and response to future long-term global warming.