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1.
Sci Adv ; 10(40): eadq1152, 2024 Oct 04.
Article in English | MEDLINE | ID: mdl-39356751

ABSTRACT

Human immunodeficiency virus-1 (HIV-1) infection disrupts the homeostatic equilibrium between the host and commensal microbes. However, the dynamic changes of plasma commensal viruses and their role in HIV/simian immunodeficiency virus (SIV) pathogenesis are rarely reported. Here, we investigated the longitudinal changes of plasma virome, inflammation levels, and disease markers using an SIV-infected Macaca leonina model. Large expansions of plasma Anelloviridae, Parvoviridae, Circoviridae and other commensal viruses, and elevated levels of inflammation and D-dimer were observed since the chronic phase of SIV infection. Anelloviridae abundance appears to correlate positively with the CD4+ T cell count but negatively with SIV load especially at the acute phase, whereas other commensal viruses' abundances show opposite correlations with the two disease markers. Antiretroviral therapy slightly reduces but does not substantially reverse the expansion of commensal viruses. Furthermore, 1387 primate anellovirus open reading frame 1 sequences of more than 1500 nucleotides were annotated. The data reveal different roles of commensal viruses in SIV pathogenesis.


Subject(s)
Simian Acquired Immunodeficiency Syndrome , Simian Immunodeficiency Virus , Animals , Simian Acquired Immunodeficiency Syndrome/virology , Simian Acquired Immunodeficiency Syndrome/blood , Viral Load , Virome/genetics , Macaca , CD4 Lymphocyte Count
2.
Fitoterapia ; 179: 106238, 2024 Sep 24.
Article in English | MEDLINE | ID: mdl-39321858

ABSTRACT

Three new N-alkylated amino acid derivatives, penichrysoamides A-C (1-3), along with a new citric acid derivative, penichrysoacid A (4), a new chromanone lactone penichrysoacid B (5), and a new amide derivative, penichrysoamide D (6), as well as seven known benzamide derivatives (7-13), were isolated from the endophytic fungus Penicillium chrysogenum derived from the insect Periplaneta americana. The structures of these compounds, including their absolute configurations, were elucidated using spectroscopic and computational techniques. Biological evaluation revealed that compounds 8-13 exhibited significant COX-2 inhibitory activity, with IC50 values ranging from 275 nM to 1350 nM.

3.
Front Plant Sci ; 15: 1403048, 2024.
Article in English | MEDLINE | ID: mdl-39286839

ABSTRACT

Understanding the correlation between topography, species biomass and species life stage would allow forest managers to better foster carbon storage in forests. Using census data from a 60-ha plot in south China, we first quantified aboveground biomass (AGB) and how much it varied among different topographies. Next, the specific contribution of 42 dominant species to total aboveground biomass was analyzed for each of the different topographies. We also explored whether these species-topography associations changed, in terms of species' AGB distribution, during each of the three life stages (sapling, juvenile, adult) for these 42 species. Our results showed that the average AGB was 368.79 Mg ha-1 and that it varied noticeably among the four topographies (Low valley, Slope, High valley and Ridge, which were classified by using fuzzy C-mean clustering based on elevation, convexity, and slope). AGB was significantly lower in the two valleys than in the two other topographies. Of the 42 species, 88.1% showed topographic preferences, and 78.6% appeared to exhibit topographic preferences that changed with life stage. Our work highlights the importance of topography and life stage in species biomass distribution and suggests that different combinations of species and life stages, based on species topographic preferences across life stages, may be better suited in different tropical rainforest topographies to maximize carbon storage overall.

4.
Talanta ; 281: 126901, 2024 Sep 16.
Article in English | MEDLINE | ID: mdl-39298802

ABSTRACT

Detection of volatile organic compounds (VOCs) is crucial in industrial production, environmental monitoring, and public safety. VOCs sensors need to be intrinsically safe, given the flammability and toxicity of common VOCs. Fiber optic sensors offer a passive and flexible solution for VOCs detection, attracting significant attention from researchers. In this study, ZIF-8, a subset of metal-organic frameworks, is applied to a side-polished silicon wafer, forming an open-cavity optical fiber Fabry-Pérot interferometer (FPI) with a fiber patch cable and a 3D-printed structural part. The sensing performance for prevalent VOCs, including methylbenzene, methanol, and ethanol, is experimentally explored, exhibiting sensitivities of 0.118 p.m./ppm, 0.177 p.m./ppm, and 0.412 p.m./ppm, respectively. Sensitivity differences are analyzed and demonstrated at the molecular level. The proposed technologies offer advantages such as easy fabrication, intrinsic safety, small size, and good selectivity, providing an alternative for VOCs detection in industrial production.

5.
J Pharm Biomed Anal ; 251: 116404, 2024 Dec 15.
Article in English | MEDLINE | ID: mdl-39154578

ABSTRACT

Sepsis is a life-threatening condition and usually be treated with antibiotics, which however often has severe side effects. This work proposed a novel Chinese traditional medicine JINHONG (JH) decoction for therapy of sepsis. We first identified the chemical constituents of JH decoction by using high-performance liquid chromatography and mass spectrometry (HPLC-MS). Then, we constructed a model mouse for sepsis by using cecal ligation and puncture (CLP). Metagenomic sequencing method was used to compare the diversity and abundance of the gut microbiota between normal, disease model, JH decoction-treatment and antibiotic-treatment mice. Many indices including the number of platelets, CD62p and CD63 content, AQP2 and AQP8 level, as well as the expression level of protein C confirmed that the sepsis resulted in serious pathological damage, while all of these indices could be reversed by JH decoction and antibiotics. The diversity and abundance of intestinal flora decreased in CLP mice, and the decrements aggravated after antibiotic treatment while can be recovered by JH decoction treatment. The abundance of anti-inflammatory Ruminococcaceae increased after JH decoction treatment, indicating that JH decoction could ameliorate pathology associated with sepsis in CLP model via modulating the intestinal flora. This study demonstrates that JH decoction could treat sepsis clinically without obvious adverse effects on gut microbiota.


Subject(s)
Disease Models, Animal , Drugs, Chinese Herbal , Gastrointestinal Microbiome , Sepsis , Animals , Gastrointestinal Microbiome/drug effects , Sepsis/drug therapy , Sepsis/microbiology , Drugs, Chinese Herbal/pharmacology , Mice , Male , Anti-Bacterial Agents/pharmacology , Chromatography, High Pressure Liquid/methods , Cecum/microbiology , Mice, Inbred C57BL
6.
J Agric Food Chem ; 72(33): 18520-18527, 2024 Aug 21.
Article in English | MEDLINE | ID: mdl-39105744

ABSTRACT

Genome mining in association with the OSMAC (one strain, many compounds) approach provides a feasible strategy to extend the chemical diversity and novelty of natural products. In this study, we identified the biosynthetic gene cluster (BGC) of restricticin, a promising antifungal agent featuring a reactive primary amine, from the fungus Aspergillus sclerotiorum LZDX-33-4 by genome mining. Combining heterologous expression and the OSMAC strategy resulted in the production of a new hybrid product (1), along with N-acetyl-restricticin (2) and restricticinol (3). The structure of 1 was determined by spectroscopic data, including optical rotation and electronic circular dichroism (ECD) calculations, for configurational assignment. Compound 1 represents a fusion of restricticin and phytotoxic cichorin. The biosynthetic pathway of 1 was proposed, in which the condensation of a primary amine of restricticin with a precursor of cichorine was postulated. Compound 1 at 5 mM concentration inhibited the growth of the shoots and roots of Lolium perenne, Festuca arundinacea, and Lactuca sativa with inhibitory rates of 71.3 and 88.7% for L. perenne, 79.4 and 73.0% for F. arundinacea, and 58.2 and 52.9% for L. sativa. In addition, compound 1 at 25 µg/mL showed moderate antifungal activity against Fusarium fujikuroi and Trichoderma harzianum with inhibition rates of 22.6 and 31.6%, respectively. These results suggest that heterologous expression in conjunction with the OSMAC approach provides a promising strategy to extend the metabolite novelty due to the incorporation of endogenous metabolites from the host strain with exogenous compounds, leading to the production of more complex compounds and the acquisition of new physiological functions.


Subject(s)
Lactuca , Lolium , Lolium/genetics , Lolium/drug effects , Lolium/growth & development , Lolium/metabolism , Lactuca/drug effects , Lactuca/genetics , Lactuca/growth & development , Multigene Family , Festuca/genetics , Festuca/metabolism , Festuca/microbiology , Festuca/drug effects , Festuca/growth & development , Fungicides, Industrial/pharmacology , Fungicides, Industrial/chemistry , Fungicides, Industrial/metabolism , Fungal Proteins/genetics , Fungal Proteins/metabolism , Fungal Proteins/chemistry , Biosynthetic Pathways , Plant Roots/genetics , Plant Roots/metabolism , Plant Roots/growth & development , Plant Roots/drug effects , Plant Roots/microbiology , Molecular Structure , Genome, Fungal , Ascomycota/genetics , Ascomycota/drug effects , Ascomycota/metabolism , Fusarium/drug effects , Fusarium/genetics , Fusarium/growth & development
7.
PLoS One ; 19(8): e0306530, 2024.
Article in English | MEDLINE | ID: mdl-39110679

ABSTRACT

Heatmap-based cattle pose estimation methods suffer from high network complexity and low detection speed. Addressing the issue of cattle pose estimation for complex scenarios without heatmaps, an end-to-end, lightweight cattle pose estimation network utilizing a reparameterized network and an attention mechanism is proposed to improve the overall network performance. The EfficientRepBiPAN (Efficient Representation Bi-Directional Progressive Attention Network) module, incorporated into the neck network, adeptly captures target features across various scales while also mitigating model redundancy. Moreover, a 3D parameterless SimAM (Similarity-based Attention Mechanism) attention mechanism is introduced into the backbone to capture richer directional and positional feature information. We constructed 6846 images to evaluate the performance of the model. The experimental results demonstrate that the proposed network outperforms the baseline method with a 4.3% increase in average accuracy at OKS = 0.5 on the test set. The proposed network reduces the number of floating-point computations by 1.0 G and the number of parameters by 0.16 M. Through comparative evaluations with heatmap and regression-based models such as HRNet, HigherHRNet, DEKR, DEKRv2, and YOLOv5-pose, our method improves AP0.5 by at least 0.4%, reduces the number of parameters by at least 0.4%, and decreases the amount of computation by at least 1.0 GFLOPs, achieving a harmonious balance between accuracy and efficiency. This method can serve as a theoretical reference for estimating cattle poses in various livestock industries.


Subject(s)
Algorithms , Cattle , Animals , Image Processing, Computer-Assisted/methods , Neural Networks, Computer
8.
Ann Rheum Dis ; 2024 Jul 31.
Article in English | MEDLINE | ID: mdl-39084885

ABSTRACT

OBJECTIVES: Viruses have been considered as important participants in the development of rheumatoid arthritis (RA). However, the profile of enteric virome and its role in RA remains elusive. This study aimed to investigate the atlas and involvement of virome in RA pathogenesis. METHODS: Faecal samples from 30 pairs of RA and healthy siblings that minimise genetic interferences were collected for metagenomic sequencing. The α and ß diversity of the virome and the virome-bacteriome interaction were analysed. The differential bacteriophages were identified, and their correlations with clinical and immunological features of RA were analysed. The potential involvement of these differential bacteriophages in RA pathogenesis was further investigated by auxiliary metabolic gene annotation and molecular mimicry study. The responses of CD4+ T cells and B cells to the mimotopes derived from the differential bacteriophages were systemically studied. RESULTS: The composition of the enteric bacteriophageome was distorted in RA. The differentially presented bacteriophages correlated with the immunological features of RA, including anti-CCP autoantibody and HLA-DR shared epitope. Intriguingly, the glycerolipid and purine metabolic genes were highly active in the bacteriophages from RA. Moreover, peptides of RA-enriched phages, in particular Prevotella phage and Oscillibacter phage could provoke the autoimmune responses in CD4+ T cells and plasma cells via molecular mimicry of the disease-associated autoantigen epitopes, especially those of Bip. CONCLUSIONS: This study provides new insights into enteric bacteriophageome in RA development. In particular, the aberrant bacteriophages demonstrated autoimmunity-provoking potential that would promote the occurrence of the disease.

9.
Bioresour Technol ; 406: 130996, 2024 Aug.
Article in English | MEDLINE | ID: mdl-38885729

ABSTRACT

Microalgae immobilization in alginate beads shows promise for biomass production and water pollution control. However, carrier instability and mass transfer limitations are challenges. This study introduces buoyant barium alginate bubble beads (BABB), which offer exceptional stability and enhance Chlorella vulgaris growth. In just 12 days, compared to traditional calcium alginate beads, BABB achieved a 20 % biomass increase while minimizing cell leakage and simplifying harvesting. BABB optimization involved co-immobilization with BG-11 medium, enrichment of CO2 in internal bubbles, and the integration of Fe nanoparticles (FeNPs). In the open raceway pond reactor, these optimizations resulted in a 39 % increase in biomass over 7 days compared to the unoptimized setup in closed flasks. Furthermore, enhancements in pigment and organic matter production were observed, along with improved removal of ammonia nitrogen and phosphate. These results highlight the overall advantages of BABB for microalgae immobilization, offering a scientific foundation for their effective utilization.


Subject(s)
Alginates , Chlorella vulgaris , Glucuronic Acid , Chlorella vulgaris/growth & development , Alginates/chemistry , Glucuronic Acid/chemistry , Hexuronic Acids/chemistry , Biomass , Cells, Immobilized/metabolism , Barium/chemistry , Microalgae/growth & development , Microspheres , Bioreactors , Carbon Dioxide
10.
J Orthop Translat ; 46: 103-115, 2024 May.
Article in English | MEDLINE | ID: mdl-38841339

ABSTRACT

Background: Reactive oxygen species (ROS), predominantly generated by mitochondria, play a crucial role in the pathogenesis of intervertebral disc degeneration (IVDD). Reduction of ROS levels may be an effective strategy to delay IVDD. In this study, we assessed whether umbilical cord mesenchymal stem cell-exosomes (UCMSC-exos) can be used to treat IVDD by suppressing ROS production caused by mitochondrial dysfunction. Materials and methods: Human UCMSC-exos were isolated and identified. Nucleus pulposus cells (NPCs) were stimulated with H2O2 in the presence or absence of exosomes. Then, 4D label free quantitative (4D-LFQ) proteomics were used to analyze the differentially expressed (DE) proteins. Mitochondrial membrane potential (MMP), mitochondrial ROS and protein levels were determined via immunofluorescence staining, flow cytometry and western blotting respectively. Additionally, high-throughput sequencing was performed to identify the DE miRNAs in NPCs. Finally, therapeutic effects of UCMSC-exos were investigated in a puncture-induced IVDD rat model. Degenerative grades of rat IVDs were assessed using magnetic resonance imaging and histochemical staining. Results: UCMSC-exos effectively improved the viability of NPCs and restored the expression of the extracellular matrix (ECM) proteins, collagen type II alpha-1 (COL2A1) and matrix metalloproteinase-13 induced by H2O2. Additionally, UCMSC-exos not only reduced the total intracellular ROS and mitochondrial superoxide levels, but also increased MMP in pathological NPCs. 4D-LFQ proteomics and western blotting further revealed that UCMSC-exos up-regulated the levels of the mitochondrial protein, mitochondrial transcription factor A (TFAM), in H2O2-induced NPCs. High-throughput sequencing and qRT-PCR uncovered that UCMSC-exos down-regulated the levels of miR-194-5p, a potential negative regulator of TFAM, induced by H2O2. Finally, in vivo results showed that UCMSC-exos injection improved the histopathological structure and enhanced the expression levels of COL2A1 and TFAM in the rat IVDD model. Conclusions: Our findings suggest that UCMSC-exos promote ECM synthesis, relieve mitochondrial oxidative stress, and attenuate mitochondrial dysfunction in vitro and in vivo, thereby effectively treating IVDD. The translational potential of this article: This study provides solid experimental data support for the therapeutic effects of UCMSC-exos on IVDD, suggesting that UCMSC-exos will be a promising nanotherapy for IVDD.

11.
Ecol Lett ; 27(6): e14447, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38844351

ABSTRACT

Host specialization plays a critical role in the ecology and evolution of plant-microbe symbiosis. Theory predicts that host specialization is associated with microbial genome streamlining and is influenced by the abundance of host species, both of which can vary across latitudes, leading to a latitudinal gradient in host specificity. Here, we quantified the host specificity and composition of plant-bacteria symbioses on leaves across 329 tree species spanning a latitudinal gradient. Our analysis revealed a predominance of host-specialized leaf bacteria. The degree of host specificity was negatively correlated with bacterial genome size and the local abundance of host plants. Additionally, we found an increased host specificity at lower latitudes, aligning with the high prevalence of small bacterial genomes and rare host species in the tropics. These findings underscore the importance of genome streamlining and host abundance in the evolution of host specificity in plant-associated bacteria along the latitudinal gradient.


Subject(s)
Genome Size , Host Specificity , Plant Leaves , Symbiosis , Plant Leaves/microbiology , Bacteria/genetics , Bacteria/classification , Genome, Bacterial , Trees/microbiology
13.
Ecol Evol ; 14(4): e11219, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38628920

ABSTRACT

Fallback foods (FBF), categorized into staple and filler types, are suboptimal food sources chosen by animals in response to a scarcity of preferred food items during specific periods. Using lichens as FBF by Yunnan snub-nosed monkeys (Rhinopithecus bieti) represents a distinctive ecological adaptation and evolutionary development within nonhuman primates. This study delves into the annual dietary choices of the species to address issues, elucidate the nutritional value, and understand the ecological significance of lichens for this primate species, which resides at the highest altitudes and experiences the coldest weather among global primates. The findings reveal that the lichens consumed by the monkeys serve as the staple FBF, with Bryoria spp. and Usnea longissima being the primary dietary species. The former is the preferred choice, providing higher digestible fiber (neutral detergent fiber) levels but lower tannin, fat, ADF, and energy levels. During the dry season, lichens dominate as the monkeys' primary food and nutritional resources. In the wet season, they act as a fundamental food selection rather than an ideal dietary choice, substituting nutrients from fruits, seeds, and leaves. Compared to other Asian colobine counterparts, this species exhibits the highest lichen consumption but the lowest proportions of leaves, flowers, and seeds. This study provides valuable evidence and information for developing or amending conservation strategies and guidelines for the dietary management of captive breeding of monkeys, one of the world's critically endangered primate species.

14.
Sci Rep ; 14(1): 5710, 2024 Mar 08.
Article in English | MEDLINE | ID: mdl-38459239

ABSTRACT

Aiming at oil extraction from a tight reservoir, the Jilin oil field was selected as the research object of this study. Based on the molecular structures of conventional long-chain alkyl anionic surfactants, a new temperature-resistant anionic/nonionic surfactant (C8P10E5C) was prepared by introducing polyoxyethylene and polyoxypropylene units into double-chain alcohols. The resulting structures were characterized by Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy (1H-NMR), and electrospray ionization mass spectrometry (ESI-MS). Then, based on surface tension, interfacial tension, adsorption resistance, wettability, and emulsification performance tests, the performance of C8P10E5C was evaluated. The FT-IR, ESI-MS, and NMR spectra confirmed that C8P10E5C was successfully prepared. The critical micelle concentration (CMC) of C8P10E5C in water was 2.9510 × 10-4 mol/L (the corresponding mass concentration is 0.26%), and the surface tension of the aqueous C8P10E5C solution at this concentration was 30.5728 mN/m. At 0.3% concentration, the contact angle of the C8P10E5C solution was 31.4°, which is 60.75% lower than the initial contact angle. Under high-temperature conditions, C8P10E5C can still reduce the oil-water interfacial tension to 10-2 mN/m, exhibiting good temperature resistance. At 110 °C, upon adsorption to oil sand, the C8P10E5C solution could reduce the oil-water interfacial tension to 0.0276 mN/m, and the interfacial tension can still reach the order of 10-2 mN/m, indicating that C8P10E5C has strong anti-adsorption capability. Additionally, it has good emulsifying performance; upon forming an emulsion with crude oil, the highest drainage rate was only 50%. The forced imbibition oil recovery of C8P10E5C is 65.8%, which is 38.54, 24.22, and 27.25% higher than those of sodium dodecyl benzene sulfonate, alkyl polyoxyethylene ether carboxylate, and alkyl ether carboxylate, respectively.

15.
World J Microbiol Biotechnol ; 40(5): 150, 2024 Mar 29.
Article in English | MEDLINE | ID: mdl-38548998

ABSTRACT

Microalgae have emerged as potential candidates for biomass production and pollutant removal. However, expensive biomass harvesting, insufficient biomass productivity, and low energy intensity limit the large-scale production of microalgae. To break through these bottlenecks, a novel technology of immobilized microalgae culture coupled with wastewater treatment has received increasing attention in recent years. In this review, the characteristics of two immobilized microalgae culture technologies are first presented and then their mechanisms are discussed in terms of biofilm formation theories, including thermodynamic theory, Derjaguin-Landau-Verwei-Overbeek theory (DLVO) and its extended theory (xDLVO), as well as ionic cross-linking mechanisms in the process of microalgae encapsulated in alginate. The main factors (algal strains, carriers, and culture conditions) affecting the growth of microalgae are also discussed. It is also summarized that immobilized microalgae show considerable potential for nitrogen and phosphorus removal, heavy metal removal, pesticide and antibiotic removal in wastewater treatment. The role of bacteria in the cultivation of microalgae by immobilization techniques and their application in wastewater treatment are clarified. This is economically feasible and technically superior. The problems and challenges faced by immobilized microalgae are finally presented.


Subject(s)
Microalgae , Water Purification , Wastewater , Phosphorus , Nitrogen/analysis , Biomass
16.
Sci Total Environ ; 926: 171829, 2024 May 20.
Article in English | MEDLINE | ID: mdl-38537812

ABSTRACT

In recent years, the use of electronic vaping products (also named e-cigarettes) has increased due to their appealing flavors and nicotine delivery without the combustion of tobacco. Although the hazardous substances emitted by e-cigarettes are largely found to be much lower than combustible cigarettes, second-hand exposure to e-cigarette aerosols is not completely benign for bystanders. This work reviewed and synthesized findings on the second-hand exposure of aerosols from e-cigarettes and compared the results with those of the combustible cigarettes. In this review, different results were integrated based upon sampling locations such as residences, vehicles, offices, public places, and experimental exposure chambers. In addition, the factors that influence the second-hand exposure levels were identified by objectively reviewing and integrating the impacts of combustible cigarettes and e-cigarettes on the environment. It is a challenge to compare the literature data directly to assess the effect of smoking/vaping on the indoor environment. The room volume, indoor air exchange rate, puffing duration, and puffing numbers should be considered, which are important factors in determining the degree of pollution. Therefore, it is necessary to calculate the "emission rate" to normalize the concentration of pollutants emitted under various experimental conditions and make the results comparable. This review aims to increase the awareness regarding the harmful effects of the second-hand exposure to aerosols coming from the use of cigarettes and e-cigarettes, identify knowledge gaps, and provide a scientific basis for future policy interventions with regard to the regulation of smoking and vaping.


Subject(s)
Electronic Nicotine Delivery Systems , Tobacco Products , Smoking , Nicotine , Aerosols
17.
Small ; 20(29): e2311299, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38366314

ABSTRACT

Silicon (Si) anode has attracted broad attention because of its high theoretical specific capacity and low working potential. However, the severe volumetric changes of Si particles during the lithiation process cause expansion and contraction of the electrodes, which induces a repeatedly repair of solid electrolyte interphase, resulting in an excessive consuming of electrolyte and rapid capacity decay. Clearly known the deformation and stress changing at µÎµ resolution in the Si-based electrode during battery operation provides invaluable information for the battery research and development. Here, an in operando approach is developed to monitor the stress evolution of Si anode electrodes via optical fiber Bragg grating (FBG) sensors. By implanting FBG sensor at specific locations in the pouch cells with different Si anodes, the stress evolution of Si electrodes has been systematically investigated, and Δσ/areal capacity is proposed for stress assessment. The results indicate that the differences in stress evolution are nested in the morphological changes of Si particles and the evolution characteristics of electrode structures. The proposed technique provides a brand-new view for understanding the electrochemical mechanics of Si electrodes during battery operation.

18.
Sci Total Environ ; 921: 170986, 2024 Apr 15.
Article in English | MEDLINE | ID: mdl-38373450

ABSTRACT

Soil microbial necromass carbon is an important component of the soil organic carbon (SOC) pool which helps to improve soil fertility and texture. However, the spatial pattern and variation mechanisms of fungal- and bacterial-derived necromass carbon at local scales in tropical rainforests are uncertain. This study showed that microbial necromass carbon and its proportion in SOC in tropical montane rainforest exhibited large spatial variation and significant autocorrelation, with significant high-high and low-low clustering patterns. Microbial necromass carbon accounted for approximately one-third of SOC, and the fungal-derived microbial necromass carbon and its proportion in SOC were, on average, approximately five times greater than those of bacterial-derived necromass. Structural equation models indicated that soil properties (SOC, total nitrogen, total phosphorus) and topographic features (elevation, convexity, and aspect) had significant positive effects on microbial necromass carbon concentrations, but negative effects on its proportions in SOC (especially the carbon:nitrogen ratio). Plant biomass also had significant negative effects on the proportion of microbial necromass carbon in SOC, but was not correlated with its concentration. The different spatial variation mechanisms of microbial necromass carbon and their proportions in SOC are possibly related to a slower accumulation rate of microbial necromass carbon than of plant-derived organic carbon. Geographic spatial correlations can significantly improve the microbial necromass carbon model fit, and low sampling resolution may lead to large uncertainties in estimating soil carbon dynamics at specific sites. Our work will be valuable for understanding microbial necromass carbon variation in tropical forests and soil carbon prediction model construction with microbial participation.


Subject(s)
Rainforest , Soil , Soil/chemistry , Carbon , Soil Microbiology , Forests , Nitrogen/analysis
19.
J Environ Manage ; 353: 120288, 2024 Feb 27.
Article in English | MEDLINE | ID: mdl-38335600

ABSTRACT

The spatial distribution of plant, soil, and microbial carbon pools, along with their intricate interactions, presents a great challenge for the current carbon cycle research. However, it is not clear what are the characteristics of the spatial variability of these carbon pools, particularly their cross-scale relationships. We investigated the cross-scale spatial variability of microbial necromass carbon (MNC), soil organic carbon (SOC) and plant biomass (PB), as well as their correlation in a tropical montane rainforest using multifractal analysis. The results showed multifractal spatial variations of MNC, SOC, and PB, demonstrating their adherence to power-law scaling. MNC, especially low MNC, exhibited stronger spatial heterogeneity and weaker evenness compared with SOC and PB. The cross-scale correlation between MNC and SOC was stronger than their correlations at the measurement scale. Furthermore, the cross-scale spatial variability of MNC and SOC exhibited stronger and more stable correlations than those with PB. Additionally, this research suggests that when SOC and PB are both low, it is advisable for reforestations to potentiate MNC formation, whereas when both SOC and PB are high some thinning can be advisable to favour MNC formation. Thus, these results support the utilization of management measures such as reforestation or thinning as nature-based solutions to regulate carbon sequestration capacity of tropical forests by affecting the correlations among various carbon pools.


Subject(s)
Carbon Sequestration , Rainforest , Carbon , Soil , Forests
20.
Sci Rep ; 14(1): 2305, 2024 01 27.
Article in English | MEDLINE | ID: mdl-38280899

ABSTRACT

This transition from gathering to cultivation is a significant aspect of studying early agricultural practices. Fruit trees are an essential component of food resources and have played a vital role in both ancient and modern agricultural production systems. The jujube (Ziziphus jujuba Mill.), with its long history of cultivation in northern China, holds great importance in uncovering the diet of prehistoric humans and understanding the origins of Chinese agricultural civilization. This paper focuses on the domestication of jujube by analyzing the morphology of jujube stones found in three Neolithic sites in northern China's Qi River basin, Zhujia, Wangzhuang, and Dalaidian. The measurements of these jujube kernels are compared with those found in other areas of northern China, as well as modern jujube kernels that were collected. The measurements revealed that the length-to-diameter (L/D) ratio of sour jujube kernels ranged from 1.36 to 1.78, whereas the L/D ratio of cultivated jujube stones varied between 1.96 and 4.23. Furthermore, jujube stones obtained from Zhujia and Wangzhuang sites exhibit pointed ends and possess an elongated oval or narrow oval shape overall, which is indicative of clearly artificial domestication traits. Therefore, this study suggests that jujube was selected and cultivated as an important food supplement in the Qi River basin no later than around 6200 BP.


Subject(s)
Ziziphus , Humans , Qi , Rivers , Fruit , China
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