Vulnerability and driving mechanism of four typical grasslands in China under the coupled impacts of climate change and human activities.

Understanding of how different grasslands types respond to climate change and human activities across different spatial and temporal dimensions is crucial for devising effective strategies to prevent grasslands degradation. In this study, we developed a novel vulnerability assessment model for grasslands that intricately evaluates the combined impact of climate change and human activities. We then applied this model to analyze the vulnerability and driving mechanism of four representative Chinese grasslands to climate change and human activities. Our findings indicate that the vulnerability of the four grasslands would show a pattern of higher in the west and lower in the east under the influence of climate change alone. However, when human activities are factored in, the vulnerability across the four grasslands tends to homogenize, with human activities notably reducing the vulnerability of alpine grasslands in the west and, conversely, increasing the vulnerability of grasslands in the east. Furthermore, our study reveals distinct major environmental drivers of grasslands vulnerability across different regions. The two western alpine grasslands exhibit higher vulnerability to annual mean temperature and isothermality compared to the eastern temperate grasslands, while their vulnerability to precipitation of the coldest quarter is lower than that of the eastern temperate grasslands. These findings are helpful for understanding the multifaceted causes and mechanisms of grasslands degradation, providing a scientific foundation for the sustainable management and conservation of grassland resources.

Exploring the antimicrobial activity of rare ginsenosides and the progress of their related pharmacological effects.

BACKGROUND: Panax ginseng C. A. Mey is a precious medicinal resource that could be used to treat a variety of diseases. Saponins are the most important bioactive components of, and rare ginsenosides (Rg3, Rh2, Rk1 and Rg5, etc.) refer to the chemical structure changes of primary ginsenosides through dehydration and desugarization reactions, to obtain triterpenoids that are easier to be absorbed by the human body and have higher activity. PURPOSE: At present, the research of P. ginseng. is widely focused on anticancer related aspects, and there are few studies on the antibacterial and skin protection effects of rare ginsenosides. This review summarizes the rare ginsenosides related to bacterial inhibition and skin protection and provides a new direction for P. ginseng research. METHODS: PubMed and Web of Science were searched for English-language studies on P. ginseng published between January 2002 and March 2024. Selected manuscripts were evaluated manually for additional relevant references. This review includes basic scientific articles and related studies such as prospective and retrospective cohort studies. CONCLUSION: This paper summarizes the latest research progress of several rare ginsenosides, discusses the antibacterial effect of rare ginsenosides, and finds that ginsenosides can effectively protect the skin and promote wound healing during use, so as to play an efficient antibacterial effect, and further explore the other medicinal value of ginseng. It is expected that this review will provide a wider understanding and new ideas for further research and development of P. ginseng drugs.

Heterozygous variants in USP25 cause genetic generalized epilepsy.

USP25 encodes ubiquitin-specific proteases 25, a key member of deubiquitinating enzyme family and is involved in neural fate determination. Although abnormal expression in Down's syndrome was reported previously, the specific role of USP25 in human diseases has not been defined. In this study, we performed trio-based whole exome sequencing in a cohort of 319 cases (families) with generalized epilepsy of unknown etiology. Five heterozygous USP25 variants including two de novo and three co-segregated variants were determined in eight individuals affected by generalized seizures and/or febrile seizures from five unrelated families. The frequency of USP25 variants showed a significantly high aggregation in this cohort compared to the East Asian population and all populations in the gnomAD database. The mean onset ages of febrile and afebrile seizures were 10 months (infancy) and 11.8 years (juvenile), respectively. The patients achieved seizure freedom except one had occasional nocturnal seizures at the last follow-up. Two patients exhibited intellectual disability. Usp25 was ubiquitously expressed in mouse brain with two peaks on embryonic days (E14‒E16) and postnatal day 21, respectively. Similarly, USP25 expressed in fetus/early childhood stage with a second peak at approximately 12‒20 years old in human brain, consistent with the seizure onset age at infancy and juvenile in the patients. To investigate the functional impact of USP25 deficiency in vivo, we established Usp25 knock-out mice, which showed increased seizure susceptibility compared to wild-type mice in pentylenetetrazol-induced seizure test. To explore the impact of USP25 variants, we employed multiple functional detections. In HEK293T cells, the severe phenotype associated variant (p.Gln889Ter) led to a significant reduction of mRNA and protein expressions but formed a stable truncated dimers with increment of deubiquitinating enzyme activities and abnormal cellular aggregations, indicating a gain-of-function effect. The p.Gln889Ter and p.Leu1045del increased neuronal excitability in mice brain, with a higher firing ability in p.Gln889Ter. These functional impairments align with the severity of the observed phenotypes, suggesting a genotype-phenotype correlation. Hence, a moderate association between USP25 and epilepsy was noted, indicating USP25 is potentially a predisposing gene for epilepsy. Our results from Usp25 null mice and the patient-derived variants indicated that USP25 would play epileptogenic role via loss-of-function or gain-of-function effects. The truncated variant p.Gln889Ter would have profoundly different effect on epilepsy. Together, our results underscore the significance of USP25 heterozygous variants in epilepsy, thereby highlighting the critical role of USP25 in the brain.

A novel hybrid model for species distribution prediction using neural networks and Grey Wolf Optimizer algorithm.

Neural networks are frequently employed to model species distribution through backpropagation methods, known as backpropagation neural networks (BPNN). However, the complex structure of BPNN introduces parameter settings challenges, such as the determination of connection weights, which can affect the accuracy of model simulation. In this paper, we integrated the Grey Wolf Optimizer (GWO) algorithm, renowned for its excellent global search capacity and rapid convergence, to enhance the performance of BPNN. Then we obtained a novel hybrid algorithm, the Grey Wolf Optimizer algorithm optimized backpropagation neural networks algorithm (GNNA), designed for predicting species' potential distribution. We also compared the GNNA with four prevalent species distribution models (SDMs), namely the generalized boosting model (GBM), generalized linear model (GLM), maximum entropy (MaxEnt), and random forest (RF). These models were evaluated using three evaluation metrics: the area under the receiver operating characteristic curve, Cohen's kappa, and the true skill statistic, across 23 varied species. Additionally, we examined the predictive accuracy concerning spatial distribution. The results showed that the predictive performance of GNNA was significantly improved compared to BPNN, was significantly better than that of GLM and GBM, and was even comparable to that of MaxEnt and RF in predicting species distributions with small sample sizes. Furthermore, the GNNA demonstrates exceptional powers in forecasting the potential non-native distribution of invasive plant species.

[Photochemical Mechanism and Control Strategy Optimization for Summertime Ozone Pollution in Yining City].

To explore the formation mechanism of the ozone （O3） and emission reduction strategy in a northwestern city， an extensive field campaign was conducted in summertime in 2021 in Yining City， in which the 0-D box model incorporating the latest explicit chemical mechanism （MCMv3.3.1） was applied for the first time to quantify the O3-NOx-VOCs sensitivity and formulate a precise O3 control strategy in this city. The results showed that： ① the three indicators ï¼»i.e.， O3 formation potential （OFP）， ·OH reaction rate （k·OH）， and relative incremental reactivity （RIR）］ jointly indicated that alkenes， oxygenated volatile organic compounds （OVOCs）， and aromatics were the highest contributors among anthropogenic volatile organic compounds （AVOC） to O3 formation， and the contribution of biogenic volatile organic compounds （BVOC） also could not be ignored. Additionally， the results based on RIR calculation implied that that the acetaldehyde， ethylene， and propylene were the most sensitive individual VOCs species in Yining City. ② The in-situ photochemical O3 variations were primarily influenced by the local photochemical production and export process horizontally to downwind areas or vertically to the upper layer， and the reaction pathways of HO2·+ NO and ·OH + NO2 contributed the most to the gross Ox photochemical production （60%） and photochemical destruction production （53%）， respectively. Hence， the reduction in local emissions for O3 precursors was more essential to alleviate O3 pollution in this city. ③ The outcome based on RIR（NOx） / RIR（AVOC） and EKMA jointly suggested that the photochemical regime in this city can be considered a transitional regime that was also nearly a VOCs-limited regime. Detailed mechanism modeling based on multiple scenarios further suggested that the NOx and VOCs synergic emission reduction strategies was helpful to alleviate O3 pollution. These results are useful to provide policy-related guidance for other cities facing similar O3 pollution in northwest China.