Phosphorus limitation induced by nitrogen addition changed soil microbial community structure in a subtropical Pinus taiwanensis forest.

Soil microorganisms play an important role in the biogeochemical cycles of terrestrial ecosystems. How-ever, it is still unclear how the amount and duration of nitrogen (N) addition affect soil microbial community structure and whether there is a correlation between the changes in microbial community structure and their nutrient limi-tation status. In this study, we conducted an N addition experiment in a subtropical Pinus taiwanensis forest to simulate N deposition with three treatments: control (CK, 0 kg N·hm-2·a-1), low N (LN, 40 kg N·hm-2·a-1), and high N (HN, 80 kg N·hm-2·a-1). Basic soil physicochemical properties, phospholipid fatty acids content, and carbon (C), N and phosphorus (P) acquisition enzyme activities were measured after one and three years of N addition. The relative nutrient limitation status of soil microorganisms was analyzed using ecological enzyme stoichiometry. The results showed that one-year N addition did not affect soil microbial community structure. Three-year LN treatment significantly increased the contents of Gram-positive bacteria (G+), Gram-negative bacteria (G-), actinomycetes (ACT), and total phospholipid fatty acids (TPLFA), whereas three-year HN treatment did not significantly affect soil microbial community, indicating that bacteria and ACT might be more sensitive to N addition. Nitrogen addition exacerbated soil C and P limitation. Phosphorus limitation was the optimal explanatory factor for the changes in soil microbial community structure. It suggested that P limitation induced by N addition might be more beneficial for the growth of certain oligotrophic bacteria (e.g. G+) and the microorganisms participating in the P cycling (e.g. ACT), with consequences on soil microbial community structure of subtropical Pinus taiwanensis forest.

[Effects of nitrogen addition on the kinetic parameters of soil acid phosphomonoesterase in a Moso bamboo forest]. / æ°®æ·»åŠ å¯¹æ¯›ç«¹æž—åœŸå£¤é ¸æ€§ç£·é ¸å•é ¯é ¶åŠ¨åŠ›å­¦å‚æ•°çš„å½±å“.

Soil phosphatases are important in the mineralization of organophosphates and in the phosphorus (P) cycle. The kinetic mechanisms of phosphatases in response to nitrogen (N) deposition remain unclear. We carried out a field experiment with four different concentrations of N: 0 g N·hm-2·a-1(control), 20 g N·hm-2·a-1(low N), 40 g N·hm-2·a-1(medium N), and 80 g N·hm-2·a-1(high N) in a subtropical Moso bamboo forest. Soil samples were then collected from 0 to 15 cm depth, after 3, 5 and 7 years of N addition. We analyzed soil chemical properties and microbial biomass. Acid phosphatase (ACP) was investigated on the basis of maximum reaction velocity (Vm), Michaelis constant (Km), and catalytic efficiency (Ka). Results showed that N addition significantly decreased soil dissolved organic carbon (DOC), available phosphorus, and organophosphate content, but significantly increased soil ammonium, nitrate-N content, and Vm. There was a significant relationship between Vm and the concentrations of available phosphorus, organophosphate, and soil DOC. In general, N addition substantially increased Ka, but did not affect Km. The Km value in the high N treatment group was higher than that in the control group after five years of N addition. Km was significantly negatively associated with both available phosphorus and organophosphate. Medium and high N treatments had stronger effects on the kinetic parameters of ACP than low N treatment. Results of variation partition analysis showed that changes in soil chemical properties, rather than microbial biomass, dominated changes in Vm(47%) and Km(33%). In summary, N addition significantly affected substrate availability in Moso bamboo forest soil and modulated soil P cycle by regulating ACP kinetic parameters (especially Vm). The study would improve the understanding of the mechanisms underlying soil microorganisms-regulated soil P cycle under N enrichment. These mechanisms would identify the important parameters for improving soil P cycling models under global change scenarios.

[Spatiotemporal Distribution and Risk Assessment of Pharmaceuticals in Typical Drinking Water Sources in the Middle Reaches of the Yangtze River].

The seasonal variation and spatial distribution of pharmaceuticals in typical drinking water sources in the middle reaches of the Yangtze River were analyzed using the solid-phase extraction and high-performance liquid chromatography-tandem mass spectrometry methods. Combined with the risk entropy method, the corresponding ecological risks for aquatic organisms were evaluated. The results showed that 80% of the target pharmaceuticals were detected in the drinking water sources, with average concentrations of 0.07-13.00 ng·L-1. The concentrations of the target pharmaceuticals were lower than or comparable with those in other drinking water sources reported in China. The spatiotemporal distribution of different pharmaceuticals varied. Generally, the detection level in winter was higher than that in summer, and there was no significant difference between that upstream and that downstream. This might be mainly attributed to seasonal/regional use and emissions of the pharmaceuticals, the impact of flow rate on dilution, and the impact of temperature on biodegradation. Compared with those before the COVID-19 epidemic, the detection concentrations of the target pharmaceuticals were relatively low. The reason for this might be that the prevention and control of the epidemic reduced the use and emission of the pharmaceuticals to a certain extent, and the high rainfall and runoff strengthened the dilution of water flow. The target pharmaceuticals, especially antibiotics, posed medium or low risks to aquatic organisms (especially algae). Considering the ecological risks and genotoxicity of pharmaceuticals and the potential risks of antibiotic-resistant genes, it is suggested to strengthen the investigation, evaluation, treatment, and control of pharmaceuticals in the water environment.

[Soil enzyme stoichiometry revealed the changes of soil microbial carbon and phosphorus limitation along an elevational gradient in a Pinus taiwanensis forest of Wuyi Mountains, Southeast China]. / åœŸå£¤é ¶è®¡é‡æ­ç¤ºäº†æ­¦å¤·å±±é»„å±±æ¾æž—åœŸå£¤å¾®ç”Ÿç‰©æ²¿æµ·æ‹”æ¢¯åº¦çš„ç¢³ç£·é™åˆ¶å˜åŒ–.

Understanding changes in soil enzyme activities and ecoenzymatic stoichiometry is important for assessing soil nutrient availability and microbial nutrient limitation in mountain ecosystems. However, the variations of soil microbial nutrient limitation across elevational gradients and its driving factors in subtropical mountain forests are still unclear. In this study, we measured soil properties, microbial biomass, and enzyme activities related to carbon (C), nitrogen (N), and phosphorus (P) cycling in Pinus taiwanensis forests at different altitudes of Wuyi Mountains. By analyzing the enzyme stoichiometric ratio, vector length (VL), and vector angle (VA), the relative energy and nutrient limitation of soil microorganisms and its key regulatory factors were explored. The results showed that ß-glucosaminidase (BG) activities increased along the elevational gradient, while the activities of ß-N-acetyl glucosaminidase (NAG), leucine aminopeptidase (LAP), acid phosphatase (AcP) and (NAG+LAP)/microbial biomass carbon (MBC) and AcP/MBC showed the opposite trend. Enzyme C/N, enzyme C/P, enzyme N/P, and VL were enhanced with increasing elevation, while VA decreased, indicating a higher degree of microbial P limitation at low elevation and higher C limitation at high elevation. In addition, our results suggested that dissolved organic carbon and microbial biomass phosphorus are critical factors affecting the relative energy and nutrient limitation of soil microorganisms at different elevations. The results would provide a theoretical basis for the responses of soil carbon, nitrogen, and phosphorus availability as well as the relative limitation of microbial energy and nutrition to elevational gradients, and improve our understanding of soil biogeochemical cycle process in subtropical montane forest ecosystems.

Antidepressant Monotherapy and Combination Therapy with Acupuncture in Depressed Patients: A Resting-State Functional Near-Infrared Spectroscopy (fNIRS) Study.

Depression is a common psychiatric illness affecting over 300 million people globally. Acupuncture has been reported to be a safe complementary treatment for depression. This study is aimed to investigate the efficacy and mechanism of combining acupuncture with antidepressants in treating depression compared to the sole use of antidepressants. Seventy depression patients were randomly assigned to the treatment group (n = 50) and control group (n = 20). The treatment group received acupuncture combined antidepressants treatment for 3 weeks, while the control group took antidepressants monotherapy for 3 weeks. Among the 70 patients, 40 participants (20 control; 20 treatment) were randomized for studying functional connectivity (FC) of the dorsolateral prefrontal cortex (DLPFC) measured by the functional near-infrared spectroscopy. The primary outcome was HAMD-17 and secondary outcomes were PHQ-9, and the relationships of resting-state FC (rsFC) with the depression severity. PHQ-9 and HAMD-17 scores in the treatment group were significantly lower than those in the control group at Week 3 (p = 0.01) with effect sizes of -0.4 and -0.61 respectively. The rsFC in F1, F3, AF3, AF7, FC3, FC5 (left DLPFC, 10-20 system), AF8, and F6 (right DLPFC) in the treatment group had significant temporal correlation (p < 0.05, FDR corrected) in DLPFC compared to the channels in the control group. No significant correlation was found between the changes of rsFC and depression severity. In conclusion, depressed patients receiving acupuncture combined with antidepressants have improvement of depressive symptoms and the stronger rsFC in the DLPFC compared to those using antidepressants alone.

[Bioconversion of cellulose to methane by a consortium consisting of four microbial strains].

Cellulose was usually degraded by microbial communities in natural habitats. Construction of a simple cellulolytic consortium is necessary to understand the underlying interaction within microorganisms involved in cellulose conversion. A screening approach was developed to obtain a simple microbial community with the ability of cellulose degradation to methane. This technique was based on the method of enrichment culture accompanying with denaturing gel gradient electrophoresis (DGGE) fingerprint detection technology and roll-tube method. Moreover, a four-strain mixed culture capable of degrading cellulose to methane was isolated from Zoige alpine wetland of the Tibetan Plateau. The results showed that the microbial consortia consisted of three functional groups: the cellulolytic bacterium Clostridium glycolicum, the non-celluloytic bacteria group of Trichococcus flocculiformis and Parabacteroides merdae, and the methanogenic bacterium Methanobacterium subterraneum. This four-strain co-culture can convert cellulose to methane. In the future, the isolated cellulolytic consortia could provide a platform for controlling metabolic pathways and genetic modification involved in methane production from cellulose.

[Study on optimization gradation of substrates in vertical flow constructed wetlands].

Bio-ceramic, anthracite, zeolite, steel slag and vermiculite were used as substrate according to different kinds of gradation to treat wastewater in vertical-flow constructed wetlands simulation systems. The results show that the removal ability of COD by graded substrates according to particle size are better than single substrates, and average removal efficiency by graded bio-ceramic is up to 72.91%. The removal rate of TN by graded zeolite, which reaches 91.23%, is higher than single zeolite. No significant difference (p < 0.05) is detected with regard to organic matter and nitrogen removal between single and combined use of bio-ceramic and zeolite. The pH values in effluents of all columns filled with steel slag and anthracite are within normal limits, but phosphorus removal of all columns filled with steel slag and anthracite are lower than that filled with single substrates, except for the column filled with anthracite, vermiculite and steel slag from up to down. No difference between planted and unplanted systems can be observed. The present results probably provide a basis for vertical-flow constructed wetland design, among which based on the characteristic of wastewater proper selection of high-efficiency graded substrates, e.g., graded bio-ceramic, graded zeolite, graded anthracite, combined use of bio-ceramic, zeolite and anthracite, is a guarantee of better performance at a high hydraulic loading rate.

[Analysis on the interrelation between acupuncture-induced weight reduction and menstruation].

The effect of acupuncture induced weight reduction on menstrual activity is definitely not a negligible issue. By analyzing the existing materials about the mutual influence of neuroendocrine system and clinical trails, it is known that there exists a close interrelation between acupuncture-induced weight reduction and menstruation. Acupuncture treatment can achieve the effects of weight reduction and menstrual improvement via regulating activities of leptin, thyroid gland system and hypothalamus-pituitary-adrenal cortex axis. Clinical practice has demonstrated that acupuncture stimulation of some commonly-used acupoints for weight reduction also has a favorable regulation on menstrual activity in obesity women.

[Clinic research on heroin de-addiction effects of acupuncture and its potentiality of preventing relapse].

OBJECTIVE: To compare the effects of de-addiction with the therapy of acupuncture, acupuncture plus opium, opium plus buprenorphine and opium plus Han's instrument for de-addiction and to study the effects of the four therapeutic methods on the protracted withdrawal syndrome and craving. METHODS: The effects of de-addiction were assessed with the opiate withdrawal scale and the craving degree with visual analogue scale (VAS). RESULTS: The dominance of acupuncture treatment for withdrawal syndrome appeared to be after the 6th day, and the dominance for controlling craving showed after the 8th day, moreover, there were little side effects. CONCLUSION: Acupuncture treatment had the potentiality of preventing relapse and could be used for treating the protracted withdrawal syndrome and psychic dependence during the period between the stages of abstinence and rehabilitation.