Acquisition of Streptomycin Resistance by Oxidative Stress Induced by Hydrogen Peroxide in Radiation-Resistant Bacterium Deinococcus geothermalis.

Streptomycin is used primarily to treat bacterial infections, including brucellosis, plague, and tuberculosis. Streptomycin resistance easily develops in numerous bacteria through the inhibition of antibiotic transfer, the production of aminoglycoside-modifying enzymes, or mutations in ribosomal components with clinical doses of streptomycin treatment. (1) Background: A transposable insertion sequence is one of the mutation agents in bacterial genomes under oxidative stress. (2) Methods: In the radiation-resistant bacterium Deinococcus geothermalis subjected to chronic oxidative stress induced by 20 mM hydrogen peroxide, active transposition of an insertion sequence element and several point mutations in three streptomycin resistance (SmR)-related genes (rsmG, rpsL, and mthA) were identified. (3) Results: ISDge6 of the IS5 family integrated into the rsmG gene (dgeo_2335), called SrsmG, encodes a ribosomal guanosine methyltransferase resulting in streptomycin resistance. In the case of dgeo_2840-disrupted mutant strains (S1 and S2), growth inhibition under antibiotic-free conditions was recovered with increased growth yields in the presence of 50 µg/mL streptomycin due to a streptomycin-dependent (SmD) mutation. These mutants have a predicted proline-to-leucine substitution at the 91st residue of ribosomal protein S12 in the decoding center. (4) Conclusions: Our findings show that the active transposition of a unique IS element under oxidative stress conditions conferred antibiotic resistance through the disruption of rsmG. Furthermore, chronic oxidative stress induced by hydrogen peroxide also induced streptomycin resistance caused by point and frameshift mutations of streptomycin-interacting residues such as K43, K88, and P91 in RpsL and four genes for streptomycin resistance.

Combining Nitrogen-Doped Graphene Sheets and MoS2 : A Unique Film-Foam-Film Structure for Enhanced Lithium Storage.

With a notable advantage in terms of capacity, molybdenum disulfide has been considered a promising anode material for building high-energy-density lithium-ion batteries. However, its intrinsically low electronic conductivity and unstable electrochemistry lead to poor cycling stability and inferior rate performance. We herein describe the scalable assembly of free-standing MoS2 -graphene composite films consisting of nitrogen-doped graphene and ultrathin honeycomb-like MoS2 nanosheets. The composite has a unique film-foam-film hierarchical top-down architecture from the macroscopic to the microscopic and the nanoscopic scale, which helps rendering the composite material highly compact and leads to rapid ionic/electronic access to the active material, while also accommodating the volume variation of the sulfide upon intercalation/deintercalation of Li. The unique structural merits of the composite lead to enhanced lithium storage.

Identification of novel biomarkers and therapeutic target candidates for stasis-heat symptom pattern of acute intracerebral hemorrhage by quantitative plasma proteomics.

OBJECTIVE: To explore the novel biomarkers and therapeutic target candidates related to the stasis-heat syndrome of acute intracerebral hemorrhage (AICH). METHODS: Applying an isobaric tagging for relative and absolute quantitation-(iTRAQ-) based quantitative proteomic approach, plasma samples from AICH patients with stasis-heat, and AICH patients with non-stasis-heat and healthy control subjects were collected and analyzed to distinguish differentially expressed proteins (DEPs) correlated to AICH with stasis-heat in this block design. The standard Western blot was applied to verify DEPs. Additionally, DEPs were analyzed via bioinformatic platforms and further approved via Ingenuity Pathway Analysis (IPA). RESULTS: A total of 26 DEPs were found among AICH with the stasis-heat, AICH with non-stasis-heat, and healthy control group. The seven DEPs compared with the non-stasis-heat group are closely related to the pathogenesis of stasis heat. These proteins showed three different protein expression patterns. The alpha-1-b glycoprotein (A1BG) and copper-protein (CP) were up-regulated in the stasis-heat group, but down-regulated in the non-stasis-heat group. Compared with the non-stasis-heat group, the expression abundance of actinin, alpha 1 (ACTN1), carbonic anhydrase I (CA1), peroxiredoxin 2 (PRDX2), and vinculin (VCL) is higher in the stasis-heat group, while the CD44 is the opposite. These differences reflect that stasis-heat syndrome has more severe inflammatory immune response, coagulation disorders and damage. Bioinformatics analysis revealed that a wide variety of cellular and metabolic processes and some signaling pathways were involved in the pathophysiology of AICH with stasis-heat. AICH with stasis-heat syndrome showed more severe inflammatory reactions, tissue damage, and coagulation disorders than non-stasis heat syndrome. CONCLUSIONS: There are differences in the protein expression patterns between the stasis-heat syndrome and non-stasis-heat syndrome. These differences reflect that stasis-heat syndrome has more severe damage. CD44, CP, ACTN1, CA1, VCL, PRDX2, and A1BG could be the potential biomarkers and therapeutic target candidates of the stasis-heat subtype. This study provides a reasonable explaination for Liangxue Tongyu decoction through anti-inflammatory and brain protection treatment.

[Spatiotemporal evolution of habitat quality in three basins of Hainan Island based on InVEST model]. / 基于InVEST模型的海南岛三大流域生境质量时空演变.

Based on land use data of five periods during 1980 to 2020, using the InVEST model and the methods of land use transfer, habitat quality change rate and spatial statistical analysis, we explored the changes of habitat quality and its spatial distribution characteristics in the three major basins of Hainan Island (Nandu River, Changhua River and Wanquan River). The results showed that woodlands were the main land use type in the three basins of Hainan Island, accounting for more than 70% of the total area. From 1980 to 2020, the area of construction land increased the most, reaching up to 169.09 km2, mainly from cultivated land and woodland. The spatial distribution pattern of habitat quality in the study area was higher in the upstream and head water areas and lower in the mid and downstream regions. Overall, habitat quality index increased slightly for a short period and then decreased significantly during the study period. Among the three basins, habitat quality of Wanquan River Basin was the highest, followed by Changhua River Basin, and Nandu River Basin was the lowest. The habitat quality of Nandu River Basin fluctuated greatly and was strongly affected by human disturbance. From 1980 to 2020, the change rate of habitat quality in the three basins generally decreased by 0.5%, which was significantly degraded from 2010 to 2020. From 1980 to 2020, the spatial distribution of habitat quality in the study area displayed strong autocorrelation and significant aggregation. The hot spot area of habitat quality was mainly concentrated near the head water and upstream areas of the three basins, while the cold spot area was mainly distributed in the estuary area of the three basins, along with the mid and downstream areas of the Nandu River. These results would provide scientific reference for biodiversity conservation and ecological restoration efforts in the three basins of Hainan Island.

Gross ecosystem product accounting of national park: Taking Hainan Tropical Rainforest National Park as an example.

Hainan Tropical Rainforest National Park has the most representative and largest contiguous tropical rainforest in China, which has advantages in exploring the realization mechanism of ecological product value in national parks. Based on the basic framework of "The Technical Guideline on Gross Ecosystem Product (GEP)", we constructed a GEP accounting system in line with the characteristics of tropical rain forest national park, and calculated the GEP of Hainan Tropical Rainforest National Park in 2019. The results showed that the GEP of Hainan Tropical Rainforest National Park in 2019 was 204.513 billion yuan, and the GEP per unit area was 0.046 billion yuan·km-2. Among all the service types, the value of material services was 4.850 billion yuan, accounting for 2.4% of the total GEP in the national park. The ecosystem regulation service value was 168.891 billion yuan, accounting for 82.6%. The value of cultural services was 30.772 billion yuan, accounting for 15.0%. Among different ecosystem types, the unit area value of the tropical rain forest ecosystem represented by mountain rain forest, lowland rain forest, deciduous monsoon forest, and tropical cloud forest was much higher than that of plantation or other ecosystems, indicating the dominant role of tropical rain forest ecosystem in providing ecosystem services. In addition, based on the GEP accounting results of the national park, we put forward relevant suggestions for further exploring the realization path and realization mechanism of ecological product value.