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1.
Plant Dis ; 2024 May 29.
Artículo en Inglés | MEDLINE | ID: mdl-38812367

RESUMEN

Hylocereus megalanthus (syn. Selenecereus megalanthus), commonly known as Yanwo fruit (bird's nest fruit), is an important tropical fruit, which is popular and widely planted due to its high nutritional and economic value in southern China. In September 2022, a serious stem and fruit canker was observed on Ecuadorian variety of Yanwo fruit plant in a 0.2 ha orchard in Guangdong (N21°19'1.24" E110°7'28.49"). Almost all plants were infected and disease incidence of fruits and stems was about 80% and 90% respectively. Symptoms on the stem and fruits were small, circular or irregular, sunken, orangish brown spots that developed into cankers (Fig 1 A, B and C). Black pycnidia were embedded under the surface of the cankers at the initial stage, subsequently they became erumpent from the surface, and the infected parts rotted. Five symptomatic stems from five plants were collected, 0.2 cm2 tissues adjacent to cankers were surface sterilized and placed on potato dextrose agar (PDA) to incubate at 25 to 28 ℃. Fungal isolates each with similar morphology grew from 100% of the tissues. Colonies covered with aerial mycelium were grayish white, and then gradually turned to grayish black. Septate hyphae were hyaline to brown and constricted into arthroconidial chains. The arthroconidia were variously shaped and colored, orbicular to rectangular, hyaline to dark brown, thick-walled, and zero- to one- septate, averaging 7.7 × 3.6 µm (n>50) (Fig 1 D, E, F and G). To identify the fungus, the internal transcribed spacer region (ITS), translation elongation factor 1-alpha (tef1), beta-tubulin (tub2), histone H3 (his3) and chitin synthase (chs) gene of isolate ACCC 35488 and ACCC 35489 (Agricultural Culture Collection of China) were amplified and sequenced with primer pairs: ITS1/ITS4 (White et al. 1990), EF1-728F/EF2-rd (Carbone & Kohn 1999; O'Donnell et al.1998), TUB2Fd/ TUB4Rd(Aveskamp et al 2009), CYLH3F/H3-1b (Crous et al. 2004) and CHS-79F/CHS-345R (Carbone & Kohn 1999) (ITS: OQ381102 and PP488350; tef1: OQ408545 and PP510454; tub2: OQ408546 and PP510455; his3: OQ408544 and PP510453; chs: OQ408543 and PP510452). Sequence Blastn results showed above 99% identical with those of Neoscytalidium dimidiatum ex-type strain CPC38666. Phylogenetic tree inferred from Maximum Likelihood analysis of the combined ITS, tub2 and tef1 sequences revealed two isolates clustered with N. dimidiatum (Fig 2). Pathogenicity was tested on healthy one-year-old cuttings and fruits of Ecuadorian variety at room temperature. Six sites were pin-pricked on each stem and fruit. Both wounded stems and fruits were inoculated with spore suspensions (106 spore/ml) and 6-mm fungal plugs respectively. Sterile water and agar were used as control. The test was repeated twice. Stems and fruits were enclosed in plastic boxes with 80% relative humidity. Symptoms described above were observed on inoculated stems and fruits at five days post inoculation (Fig 1 H and I). No symptoms developed on the controls. Neoscytaliudium dimidiatum was reisolated from the cankers with a frequency of 100% via morphological and molecular analysis. This is first report of stem and fruit canker caused by N. dimidiatum on H. megalanthus in China and this disease represents a serious risk of Yanwo fruit yield losses. This fungus is widespread occurring throughout the world causing diseases on a wide variety of plants. The finding will be helpful for its prevention and control.

2.
Plant Dis ; 2024 Aug 29.
Artículo en Inglés | MEDLINE | ID: mdl-39207340

RESUMEN

Jatropha curcas L. (Euphorbiaceae), is a valuable multi-purpose crop, previously used for disease treatment and environmental restoration, recently is attention to use jatropha oil for produce biodiese. In June 2023, the leaf disease of approximately 60% of J. curcas was observed in Mazhang, Zhanjiang, Guangdong Province (E110°27'26.8'' N22°6'14.7''). Diseased leaves showed typical anthracnose symptoms of chlorotic regions with brownish sunken necrotic lesions (Figure 1). Sections from the junction of disease were surface disinfected in 75% ethanol and 3% hydrogen peroxide solution for 1 minute each. Four small pieces of infected tissue were removed from the lesion and placed on potato dextrose agar (PDA), and incubated at 25 to 28℃ in the dark. Hyphal tips from the inoculated tissues were subcultured on PDA and two isolates were purified by single spore method. The colonies on PDA were 7.8 cm diam after 10 d at 25 to 28 ℃, covered with dense, cottony, grayish-white aerial mycelium and small dark-based acervuli with orange ooze and dark brown straight setae. Conidia were hyaline, smooth-walled, aseptate, the apex and base rounded, slightly constricted near centre, 12.9 - 13.8 × 3.9 - 4.6 um (av.13.6 × 4.3 µm, n = 50). Appressoria were variable in shape, mostly simple, subglobose or irregular lobes, 5.8-9.6 × 5.7-11.2 um (Figure 2). Perithecia were not observed. These characteristics were consistent with Colletotrichum sp. (Weir, B. S., et al. 2012). Sequences of isolates ACCC 35630 and ACCC 35631 stored in Agricultural Culture Collection of China including internal transcribed spacer (ITS), actin (ACT), beta-tubulin (tub2), glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and chitin synthase (chs). were amplified (Weir et al, 2012), sequenced and submitted to GenBank (ITS: PP474979 and PP474984; ACT: PP505487 and PP505488; TUB: PP505493 and PP505494; GAPDH: PP505491 and PP505492; CHS: PP505489 and PP505490). The amplicon sizes of ITS, ACT, TUB, GAPDH, and CHS were 550, 652, 500, 264, and 301 bp, respectively. Phylogenetic analyses showed that Isolates 35630 & 35631 were clustered closely association with RHCOL1 and RHCOL3. Phylogenetic analysis with MEGA 7 using the combined ITS-ACT-CHS-GAPDH-TUB2 sequences showed that the two isolates clustered with C. queenslandicum (Figure 3). To test the pathogenicity, ten healthy leaves on plants in the field were wiped with 75% alcohol and sterile water, punctured with a sterile needle and inoculated by adding 10 uL of spore suspension (1 × 105 conidia/ml) to the wounded sites. And two other leaves were added sterile water as controls. Symptoms of anthracnose were observed on leaves similar to the disease described above after 7 days of inoculation, whereas the leaves from the controls remained asymptomatic. C. queenslandicum was reisolated from the inoculated leaves. C. queenslandicum has been reported as a pathogen causing leaf and fruit anthracnose on papaya, coffee, rambutan, avocado and Persian lime etc. in tropical and temperate regions (Kunta, M., et al. 2018), and this is the first report on J. curcas in China as well as worldwide. This disease may have a significant negative impact on J. curcas cultivation.

3.
Glob Chang Biol ; 29(15): 4430-4439, 2023 08.
Artículo en Inglés | MEDLINE | ID: mdl-37194010

RESUMEN

Microbial residues contribute to the long-term stabilization of carbon in the entire soil profile, helping to regulate the climate of the planet; however, how sensitive these residues are to climatic seasonality remains virtually unknown, especially for deep soils across environmental gradients. Here, we investigated the changes of microbial residues along soil profiles (0-100 cm) from 44 typical ecosystems with a wide range of climates (~3100 km transects across China). Our results showed that microbial residues account for a larger portion of soil carbon in deeper (60-100 cm) vs. shallower (0-30 and 30-60 cm) soils. Moreover, we find that climate especially challenges the accumulation of microbial residues in deep soils, while soil properties and climate share their roles in controlling the residue accumulation in surface soils. Climatic seasonality, including positive correlations with summer precipitation and maximum monthly precipitation, as well as negative correlations with temperature annual range, are important factors explaining microbial residue accumulation in deep soils across China. In particular, summer precipitation is the key regulator of microbial-driven carbon stability in deep soils, which has 37.2% of relative independent effects on deep-soil microbial residue accumulation. Our work provides novel insights into the importance of climatic seasonality in driving the stabilization of microbial residues in deep soils, challenging the idea that deep soils as long-term carbon reservoirs can buffer climate change.


Asunto(s)
Carbono , Microbiología del Suelo , Suelo , Carbono/análisis , China , Cambio Climático , Ecosistema , Suelo/química
4.
Glob Chang Biol ; 28(21): 6433-6445, 2022 11.
Artículo en Inglés | MEDLINE | ID: mdl-35894152

RESUMEN

Warming is known to reduce soil carbon (C) stocks by promoting microbial respiration, which is associated with the decomposition of microbial residue carbon (MRC). However, the relative contribution of MRC to soil organic carbon (SOC) across temperature gradients is poorly understood. Here, we investigated the contribution of MRC to SOC along two independent elevation gradients of our model system (i.e., the Tibetan Plateau and Shennongjia Mountain in China). Our results showed that local temperature increases were negatively correlated with MRC and SOC. Further analyses revealed that rising temperature reduced SOC via decreasing MRC, which helps to explain future reductions in SOC under climate warming. Our findings demonstrate that climate warming has the potential to reduce C sequestration by increasing the decomposition of MRC, exacerbating the positive feedback between rising temperature and CO2 efflux. Our study also considered the influence of multiple environmental factors such as soil pH and moisture, which were more important in controlling SOC than microbial traits such as microbial life-style strategies and metabolic efficiency. Together, our work suggests an important mechanism underlying long-term soil C sequestration, which has important implications for the microbial-mediated C process in the face of global climate change.


Asunto(s)
Carbono , Suelo , Carbono/metabolismo , Dióxido de Carbono , Suelo/química , Microbiología del Suelo , Temperatura
5.
New Phytol ; 231(3): 1210-1219, 2021 08.
Artículo en Inglés | MEDLINE | ID: mdl-33914920

RESUMEN

Lichens play crucial roles in sustaining the functioning of terrestrial ecosystems; however, the diversity and ecological factors associated with lichenised soil fungi remain poorly understood. To address this knowledge gap, we used a global field survey including information on fungal sequences of topsoils from 235 terrestrial ecosystems. We identified 880 lichenised fungal phylotypes across nine biomes ranging from deserts to tropical forests. The diversity and proportion of lichenised soil fungi peaked in shrublands and dry grasslands. Aridity index, plant cover and soil pH were the most important factors associated with the distribution of lichenised soil fungi. Furthermore, we identified Endocarpon, Verrucaria and Rinodina as some of the most dominant lichenised genera across the globe, and they had similar environmental preferences to the lichenised fungal community. In addition, precipitation seasonality and mean diurnal temperature range were also important in predicting the proportion of these dominant genera. Using this information, we were able to create the first global maps of the richness and the proportion of dominant genera of lichenised fungi. This work provides new insight into the global distribution and ecological preferences of lichenised soil fungi, and supports their dominance in drylands across the globe.


Asunto(s)
Micobioma , Suelo , Biodiversidad , Ecosistema , Bosques , Hongos , Microbiología del Suelo
6.
Ying Yong Sheng Tai Xue Bao ; 35(8): 2256-2266, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-39419811

RESUMEN

The Vaganov-Shashkin (VS) and VS-Lite models are the most widely used physiological processes-based models of tree-ring width. Both models can reveal the intrinsic response mechanism between tree-ring width and external climate factors. The VS model is commonly applied in climate reconstruction, wood phenology prediction, and the simulation of cambial activity, while the VS-Lite model is primarily applied in forecasting growth trends of forest. We collected papers related to the VS and VS-Lite models published between 2005 and 2023, and reviewed the fundamental principles, parameter settings, and historical development of both models, as well as the their applications in research areas of dendroclimatology, xylem phenology, and forest ecology. Then, we summarized the current issues with the models and proposed future research directions. To increase confidence in the simulation results, it is essential to optimize the parameter adjustment method of the models, consider the impact of multiple environmental factors on the physiological processes of trees, and strengthen the comparative study of the VS and VS-Lite model with other vegetation ecological models.


Asunto(s)
Árboles , Árboles/crecimiento & desarrollo , Árboles/fisiología , Modelos Teóricos , Ecosistema , Clima , Bosques , Tallos de la Planta/crecimiento & desarrollo , Madera/crecimiento & desarrollo
7.
Plant Sci ; 335: 111824, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37572966

RESUMEN

The application of potassium (K) in conjunction with nitrogen (N) has been shown to enhance N use efficiency. However, there is still a need for further understanding of the optimal ratios and molecular regulatory mechanisms, particularly in soil-cotton systems. Here, a field trial was conducted, involving varying rates of N and K, alongside pot and hydroponic experiments. The objective was to assess the impact of N-K interaction on the absorption, transport and distribution of N in cotton. The results showed that K supply at 90 and 240 kg ha-1 had a beneficial impact on N uptake and distribution to both seed and lint, resulting in the highest N use efficiency ranging from 22% to 62% and yield improvements from 20% to 123%. The increase in stem and root diameters, rather than the quantify of xylem vessels and phloem sieve tubes, facilitated the uptake and transport of N due to the provision of K. At the molecular level, K supply upregulated the expression levels of genes encoding GhNRT2.1 transporter and GhSLAH3 channel in cotton roots to promote N uptake and GhNRT1.5/NPF7.3 genes to transport N to shoot under low-N conditions. However, under high-N conditions, K supply induced anion channel genes (GhSLAH4) of roots to promote N uptake and genes encoding GhNRT1.5/NPF7.3 and GhNRT1.8/NPF7.2 transporters to facilitate NO3- unloading from xylem to mesophyll cell in high-N plants. Furthermore, K supply resulted in the upregulation of gene expression for GhGS2 in leaves, while simultaneously downregulating the expression of GhNADH-GOGAT, GhGDH1 and GhGDH3 genes in high-N roots. The enzyme activities of nitrite reductase and glutamine synthetase increased and glutamate dehydrogenase decreased, but the concentration of NO3- and soluble protein exhibited a significant increase and free amino acid decreased in the shoots subsequent to K supply.


Asunto(s)
Raíces de Plantas , Potasio , Raíces de Plantas/metabolismo , Potasio/metabolismo , Nitrógeno/metabolismo , Nitratos/metabolismo , Transporte Biológico , Proteínas de Transporte de Membrana/metabolismo
8.
Nat Commun ; 14(1): 1706, 2023 03 27.
Artículo en Inglés | MEDLINE | ID: mdl-36973286

RESUMEN

Soil contamination is one of the main threats to ecosystem health and sustainability. Yet little is known about the extent to which soil contaminants differ between urban greenspaces and natural ecosystems. Here we show that urban greenspaces and adjacent natural areas (i.e., natural/semi-natural ecosystems) shared similar levels of multiple soil contaminants (metal(loid)s, pesticides, microplastics, and antibiotic resistance genes) across the globe. We reveal that human influence explained many forms of soil contamination worldwide. Socio-economic factors were integral to explaining the occurrence of soil contaminants worldwide. We further show that increased levels of multiple soil contaminants were linked with changes in microbial traits including genes associated with environmental stress resistance, nutrient cycling, and pathogenesis. Taken together, our work demonstrates that human-driven soil contamination in nearby natural areas mirrors that in urban greenspaces globally, and highlights that soil contaminants have the potential to cause dire consequences for ecosystem sustainability and human wellbeing.


Asunto(s)
Ciudades , Ecosistema , Internacionalidad , Parques Recreativos , Contaminantes del Suelo , Suelo , Microbiota , Factores Socioeconómicos , Suelo/química , Microbiología del Suelo , Contaminantes del Suelo/análisis , Contaminantes del Suelo/química , Plásticos
9.
Pharmazie ; 67(1): 74-9, 2012 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-22393835

RESUMEN

The aim of the present study was to evaluate the impact of the UCP2-866 G/A polymorphism on the efficacy of repaglinide in treating patients with diabetes mellitus type 2 (T2DM). 370 patients with T2DM and 166 healthy volunteers were enrolled to identify UCP2-866 G/A genotypes. 16 patients with GG genotype, 14 with GA genotype and 11 with AA genotype of UCP2-866 G/A underwent an 8-week repaglinide treatment regimen. There were no differences in allele frequency of UCP2-866 G/A between T2DM patients and control subjects. The patient with AA genotype of UCP2-866 G/A had higher levels of fasting plasma glucose (FPG), 30-min and 2-h postload plasma glucose, glycated haemoglobin (HbA1c), and lower concentrations of 30-min and 2-h postload plasma insulin, homeostasis model assessment of beta cell function (HOMA-beta), deltaI30/deltaG30 compared with GG genotype. After repaglinide treatment for 8 consecutive weeks, we found that A allele carriers of UCP2 in the T2DM patients had smaller decrease in FPG (P < 0.05) and HbA1c (P < 0.05), and smaller increase in 30-min postload plasma insulin (P < 0.01) compared with GG genotypes. We demonstrated that UCP2-866 G/A polymorphism is associated with the therapeutic efficacy of repaglinide in Chinese T2DM patients.


Asunto(s)
Carbamatos/farmacología , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Diabetes Mellitus Tipo 2/genética , Hipoglucemiantes/farmacología , Canales Iónicos/genética , Proteínas Mitocondriales/genética , Piperidinas/farmacología , Adulto , Anciano , Alelos , Pueblo Asiatico/genética , Glucemia/metabolismo , Cartilla de ADN , Femenino , Genotipo , Humanos , Insulina/sangre , Células Secretoras de Insulina/fisiología , Masculino , Persona de Mediana Edad , Pruebas de Función Pancreática , Reacción en Cadena de la Polimerasa , Proteína Desacopladora 2
10.
Huan Jing Ke Xue ; 43(4): 2062-2070, 2022 Apr 08.
Artículo en Zh | MEDLINE | ID: mdl-35393830

RESUMEN

The Yangtze River Economic Belt is one of the areas with rapid economic development in China, although the intensive industrial activities have aggravated the emissions of soil pollutants in this area. Industrial activities are important sources of soil heavy metal contamination; however, the spatial distribution and main emission sources of soil heavy metal contamination in industrial regions of the economic belt remain unclear. Here, we collected data on the concentrations of eight heavy metals (Cd, Cr, Cu, Pb, Ni, Hg, As, and Zn) in the surface soils of 193 industrial regions covering 11 provinces and cities of the Yangtze River Economic Belt from China National Knowledge Infrastructure (CNKI), Web of Science, and other public databases. On this basis, we analyzed the spatial distribution characteristics of heavy metals and the contamination characteristics of typical industries. The results showed that the heavy metal contamination in agricultural land was more serious than that in industrial land. A total of 58.49%, 39.53%, and 22.64% of the agricultural land, respectively, contained levels of Cd, Zn, and Pb that exceeded the screening values of the Soil Environmental Quality Control Standard for Soil Pollution Risk of Agricultural Land (GB 15618-2018). The results of geo-accumulation index analysis showed that the contamination degree of the eight heavy metals was in the order of Cd (2.52)>Hg (1.17)>Pb (1.00)>Zn (0.90)>Cu (0.72)>As (0.02)>Cr (-0.40)>Ni(-0.48). As for the spatial distribution, Hg, Cd, As, Cu, Pb, and Zn were the main pollutants in the upstream and middle reaches of the industrial regions, whereas As, Cd, and Hg were the main pollutants in the downstream industrial regions. Different types of industry caused different types of contamination. Mining industries caused the most serious soil contamination, the main pollutants of which were Hg and Cd, followed by Cu, Pb, and Zn. Furthermore, metal processing industries mainly caused Cd and Pb contamination. The surrounding soils of chemical industries were contamination-free or only slightly polluted by the eight heavy metals, whereas petroleum processing industries mainly caused Cd contamination. Our study provides important theoretical basis for the future prevention and control of soil heavy metal contamination in industrial regions of the Yangtze River Economic Belt.


Asunto(s)
Mercurio , Metales Pesados , Contaminantes del Suelo , Cadmio/análisis , China , Monitoreo del Ambiente/métodos , Plomo/análisis , Mercurio/análisis , Metales Pesados/análisis , Medición de Riesgo , Suelo/química , Contaminantes del Suelo/análisis
11.
Sci Total Environ ; 820: 153257, 2022 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-35065115

RESUMEN

Identifying the drivers of the response of soil microbial respiration to warming is integral to accurately forecasting the carbon-climate feedbacks in terrestrial ecosystems. Microorganisms are the fundamental drivers of soil microbial respiration and its response to warming; however, the specific microbial communities and properties involved in the process remain largely undetermined. Here, we identified the associations between microbial community and temperature sensitivity (Q10) of soil microbial respiration in alpine forests along an altitudinal gradient (from 2974 to 3558 m) from the climate-sensitive Tibetan Plateau. Our results showed that changes in microbial community composition accounted for more variations of Q10 values than a wide range of other factors, including soil pH, moisture, substrate quantity and quality, microbial biomass, diversity and enzyme activities. Specifically, co-occurring microbial assemblies (i.e., ecological clusters or modules) targeting labile carbon consumption were negatively correlated with Q10 of soil microbial respiration, whereas microbial assemblies associated with recalcitrant carbon decomposition were positively correlated with Q10 of soil microbial respiration. Furthermore, there were progressive shifts of microbial assemblies from labile to recalcitrant carbon consumption along the altitudinal gradient, supporting relatively high Q10 values in high-altitude regions. Our results provide new insights into the link between changes in major microbial assemblies with different trophic strategies and Q10 of soil microbial respiration along an altitudinal gradient, highlighting that warming could have stronger effects on microbially-mediated soil organic matter decomposition in high-altitude regions than previously thought.


Asunto(s)
Microbiota , Suelo , Respiración , Suelo/química , Microbiología del Suelo , Temperatura
12.
Zhonghua Yu Fang Yi Xue Za Zhi ; 45(10): 944-8, 2011 Oct.
Artículo en Zh | MEDLINE | ID: mdl-22321599

RESUMEN

OBJECTIVE: To comprehensively evaluate the effect of interventions on obesity in Chinese pupils. METHODS: A literature research was carried out in China National Knowledge Infrastructure, Wanfang Data, VIP Database for Chinese Technical Periodicals, PubMed and the Excerpts Medica Database (EMBASE) databases to collect articles published between 1979 and 2010 concerning the effect of interventions for preventing obesity in Chinese pupils. Rate difference (RD) of the rate of obesity as the evaluation indicator was selected to Meta-analyze the effect of interventions on obesity. There are total 215 articles, in which 211 articles were written in Chinese and other articles were written in English. RESULTS: 17 literatures were used for Meta-analysis by the uniform inclusion and exclusion criteria. The results showed that the RD of obesity rate for the students in the intervention group was 3% (95%CI: 1% - 5%) after the intervention. However, the RD of obesity rate for the students in the control group was -2% (95%CI: -4% - -1%) after the intervention. Results of stratified analysis for the RD of obesity rate showed that the obesity rate for the students in the intervention group were decreased significantly after the intervention of combined programs with health education, physical exercise and nutrition interventions with moderate intervention time (1 to 2 years), the RD (95%CI) of obesity rate were 5% (2% - 8%), 3% (1% - 4%), respectively. For the studies whose baseline obesity rates was insignificant difference between the intervention group and the control group, the obesity rate for the students in the intervention group was 4% (95%CI: -7% - -1%) lower than the obesity rate for the students in the control group after the intervention. CONCLUSION: Health-education-based comprehensive intervention is effective on obesity prevention in Chinese pupils; combined intervention programs with moderate intervention time (1 to 2 years) were effective in improving efficiency of obesity prevention in pupils.


Asunto(s)
Educación en Salud , Obesidad/prevención & control , Niño , China , Humanos , Estudiantes
13.
ISME Commun ; 1(1): 71, 2021 Dec 03.
Artículo en Inglés | MEDLINE | ID: mdl-36765103

RESUMEN

Trait-based approaches provide a candidate framework for linking soil microbial community to ecosystem processes, yet how the trade-offs in different microbial traits regulate the community-level metabolic efficiency remains unknown. Herein we assessed the roles of the microbial taxa with particular trait strategies in mediating soil microbial metabolic efficiency along an altitude gradient on the Tibetan Plateau. Results showed that soil microbial metabolic efficiency declined with increasing altitude, as indicated by the increasing metabolic quotient (microbial respiration per unit biomass, qCO2) and decreasing carbon use efficiency (CUE). Both qCO2 and CUE were predominantly predicted by microbial physiological and taxonomic attributes after considering key environmental factors including soil pH, substrate quantity and quality. Specifically, the reduced metabolic efficiency was associated with higher investment into nutrient (particularly for phosphorus) acquisitions via enzymes. Furthermore, we identified key microbial assemblies selected by harsh environments (low substrate quality and temperature) as important predictors of metabolic efficiency. These results suggest that particular microbial assemblies adapted to nutrient limited and cold habitats, but at the expense of lower metabolic efficient at higher altitude. Our findings provide a candidate mechanism underlying community-level metabolic efficiency, which has important implications for microbial-mediated processes such as carbon dynamics under global climate changes.

14.
Ying Yong Sheng Tai Xue Bao ; 32(10): 3743-3752, 2021 Oct.
Artículo en Zh | MEDLINE | ID: mdl-34676737

RESUMEN

Stable isotope ratios of tree ring can effectively record climate and environmental changes during tree growth and the physiological responses of trees to such changes. Intra-annual high resolution stable isotope ratios of tree ring can provide more detailed climatic and environmental information, reveal the physiological and ecological response mechanism of trees to seasonal climatic variation, and thus with great potential in the study of paleoclimate and global change ecology. Based on the intra-annual high resolution stable isotope ratios related literature since 1990, we reviewed the research progress of intra-annual high resolution tree ring stable isotope records in the aspects of sample stripping method, chemical extraction method of α-cellulose and application, and further proposed the potential and future development direction of intra-annual high resolution tree ring stable isotope records.


Asunto(s)
Clima , Árboles , Isótopos de Carbono/análisis , Isótopos de Oxígeno/análisis , Estaciones del Año
15.
Ying Yong Sheng Tai Xue Bao ; 32(10): 3753-3760, 2021 Oct.
Artículo en Zh | MEDLINE | ID: mdl-34676738

RESUMEN

The primary hydrogen (H) source for all organic compounds in the biosphere is from water, and then participates in biogeochemical cycles through photosynthesis and plant physiological metabolism. As a new proxy of paleoclimate and paleoenvironment, stable hydrogen isotope ratios in wood lignin methoxyl groups (δ2HLM) show great advantages in the studies of paleoclimatic change and have been used to reconstruct precipitation stable hydrogen isotope ratios and paleoclimate signals in many regions. Based on the lignin application mechanism and analysis method of δ2HLM, we evaluated the stability and effectiveness of δ2HLM-measurement method from lignin content and lignin monomer composition, and expounded the tree lignin methoxyl groups' stable isotope proxies of current research outcomes. In the middle latitudes, the tree-ring δ2HLM had great potential in recording temperature signals and precipitation stable hydrogen isotope ratios. However, the study of tree-ring δ2HLM was still in its infancy as evidenced by following reasons: 1) The study area was limited to the middle latitude of the northern hemisphere, and the study subjects were limited to conifer species; 2) To compensate for the limitation of hydrogen isotopic records of nitrocellulose, high resolution tree-ring δ2HLM would be studied; 3) The potential of tree-ring δ2HLM utilization in plant physiology and forest ecology remained to be exploited.


Asunto(s)
Lignina , Árboles , Humanos , Hidrógeno/análisis , Isótopos , Lignina/análisis , Madera/química
16.
Ying Yong Sheng Tai Xue Bao ; 31(3): 753-760, 2020 Mar.
Artículo en Zh | MEDLINE | ID: mdl-32537969

RESUMEN

Phosphorus (P) is an important nutrient for plant and microbial growth. Soil P availabi-lity is poor in subtropical areas. Long-term heavy nitrogen (N) deposition might further reduce P availability. The experiment was performed in a Phyllostachys pubescens forest in Daiyun Mountain. The effects of N application on soil basic physical and chemical properties, soil P fractions, microbial biomass, and acid phosphomonoesterase activity were analyzed after three years of N application. The results showed that N application significantly increased NO3--N content and thus soil N availability, while it significantly reduced the percentage of decomposable organic P to total P, with the ratio of carbon (C) to organic P being over 200. The soil microbial biomass C, microbial biomass P, acid phosphomonoesterase, and the ratio of microbial biomass N to microbial biomass P and microbial biomass C to microbial biomass P were increased as the N application rate increased. There was a significant negative correlation between the percentage of decomposable organic P to total P and microbial biomass P. Consequently, N application enhanced soil P limitation and increased microbial P demand.


Asunto(s)
Nitrógeno , Fósforo , Biomasa , Carbono , China , Bosques , Suelo , Microbiología del Suelo
17.
Ying Yong Sheng Tai Xue Bao ; 30(5): 1754-1762, 2019 May.
Artículo en Zh | MEDLINE | ID: mdl-31107032

RESUMEN

The subtropical zone in China is one of the regions most affected by nitrogen deposition. Soil dissolved organic matter (DOM) is considered to be an important indicator of soil organic matter. Nitrogen deposition may alter the quality and quantity of soil DOM by changing soil microbial activity. In this study, we explored the effects of nitrogen addition on soil DOM content, its spectral characteristics and microbial extraceller enzyme activity in the Moso bamboo plantations by setting control (CT), low-nitrogen (LN), and high-nitrogen (HN) addition levels for three-year nitrogen addition. The results showed that there was no significant change in soil pH, dissolved organic carbon, dissolved organic nitrogen, and aroma index following nitrogen addition, while the humification index increased significantly, microbial enzyme activities increased first and then decreased with the increases of nitrogen addition. Fourier transform infrared spectroscopy results showed that soil DOM had similar absorption peaks in seven regions, and that the absorption peaks of 1000 to 1260 cm-1 were the strongest, indicating an enhanced amount of polysaccharides, alcohols, carboxyl acids, and esters after nitrogen addition. The results of three-dimensional fluorescence spectroscopy showed that soil DOM structure significantly changed following nitrogen addition, with a decrease in low-molecular substances such as protein-like substances and microbial metabolites and a significant increase in high-molecular substances such as humus-like substances. In general, nitrogen addition made soil nitrogen compatible with microbial requirements. Microorganisms decompose substances that were easily degraded in DOM. The structure of soil DOM was more complex after nitrogen addition. Therefore, short-term nitrogen deposition might be conducive to preserving soil fertility.


Asunto(s)
Nitrógeno/análisis , Poaceae , Suelo/química , Carbono , China , Sustancias Húmicas/análisis
18.
Ying Yong Sheng Tai Xue Bao ; 29(7): 2156-2162, 2018 Jul.
Artículo en Zh | MEDLINE | ID: mdl-30039652

RESUMEN

Soil P fraction, microbial biomass P (MBP), and activities of acid phosphomonoesterase (ACP) and phosphodiesterase (PD) were analyzed under evergreen broad-leaved forest, mixed forest and coniferous forest in Daiyun Mountains. The results showed that labile-P comprised only 1.0%-4.5% of soil total phosphorus (TP). The ratio of soil carbon to organic phosphorus (C:Po) was >200, indicating phosphorus limitation across the three vegetation types. Organic phosphorus (Po) was a significant fraction of soil P, which accounted for 44.8%-47.1% and 28.6%-30.6% of TP in A and B horizons, respectively. Results from the redundancy analysis showed that the changes in P fractions were mainly driven by PD in the A horizon and by ACP in the B horizon. Moreover, the activities of PD and ACP had a significant negative correlation with Po. The results suggested that phosphorus deficiency occurred in the three vegetation types, and that PD and ACP could play major roles in the depletion of soil Po in response to phosphorus limitation in subtropical forests.


Asunto(s)
Bosques , Fósforo/análisis , Suelo/química , Carbono , China , Nitrógeno
20.
Asian Pac J Cancer Prev ; 13(1): 261-7, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22502681

RESUMEN

PURPOSE: The relationship between thymidylate synthase (TS) expression and outcomes in gastric cancer (GC) patients remains controversial, although most studies reported poor survival and reduced response to fluoropyrimidine were related to high TS in tumors. We carried out a systematic review of the literature with meta-analysis to estimate the predictive value of TS expression from published studies. METHODS: We identified 24 studies analysing the outcome data in gastric cancer stratified by TS expression. Effect measures of outcome were hazard ratios (HRs) for overall survival (OS) and event-free survival (EFS), or the odds ratio (OR) for overall response rate (ORR). HRs and ORs from these eligible studies were pooled using random-effects meta- analysis. RESULTS: Fifteen studies investigated outcomes in a total of 844 patients with advanced GC, and nine studies investigated outcomes in a total of 1,235 patients with localized GC undergoing adjuvant therapy. Meta- analysis of estimates showed high TS expression was significantly associated with poor OS in the advanced setting (HR: 1.43, 95%CI: 1.08 - 1.90), and poor EFS in the adjuvant setting (HR: 1.53, 95%CI: 1.01 - 2.32). Subgroup analysis demonstrated TS expression to have even greater value in predicting OS, EFS and ORR in advanced GC patients treated with fluoropyrimidine monotherapy (HR for OS: 2.32, 95%CI: 1.53 - 3.50; HR for EFS: 1.76, 95%CI: 1.19 - 2.60; OR for ORR: 0.32, 95%CI: 0.11 - 0.95). CONCLUSION: High levels of TS expression were associated with a poorer OS for advanced GC patients compared with low levels. In the adjuvant setting, high TS expression was also associated with a worse EFS. Additional studies with consistent methodology are needed to define the precise predictive value of TS.


Asunto(s)
Neoplasias Gástricas/enzimología , Neoplasias Gástricas/mortalidad , Timidilato Sintasa/metabolismo , Ensayos Clínicos como Asunto , Humanos , Metaanálisis como Asunto , Pronóstico , Neoplasias Gástricas/patología , Tasa de Supervivencia
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