Ultrasmall and highly biocompatible carbon dots derived from natural plant with amelioration against acute kidney injury.

BACKGROUND: Acute kidney injury (AKI) refers to a tricky clinical disease, known by its high morbidity and mortality, with no real specific medicine for AKI. The carbonization product from Pollen Typhae (i.e., Pu-huang in China) has been extensively employed in clinic, and it is capable of relieving the renal damage and other diseases in China since acient times. RESULTS: Inspired by the carbonization process of Traditional Chinese Medicine (TCM), a novel species of carbon dots derived from Pollen Typhae (PT-CDs) was separated and then collected using a one-pot pyrolysis method. The as-prepared PT-CDs (4.85 ± 2.06 nm) with negative charge and abundant oxygenated groups exhibited high solubility, and they were stable in water. Moreover, the rhabdomyolysis (RM)-induced AKI rat model was used, and it was first demonstrated that PT-CDs had significant activity in improving the level of BUN and CRE, urine volume and kidney index, and histopathological morphology in RM-induced AKI rats. It is noteworthy that interventions of PT-CDs significantly reduced degree of inflammatory reaction and oxidative stress, which may be correlated with the basial potential mechanism of anti-AKI activities. Furthermore, cytotoxicity assay and biosafety evaluation exhibited high biocompatibility of PT-CDs. CONCLUSION: This study offers a novel relieving strategy for AKI based on PT-CDs and suggests its potential to be a related candidate for clinical applications.

miR-216b-5p Inhibited the Progression of Experimental Optic Neuritis via Downregulating FAS.

Objective: Present study mainly explored the effect of miR-216b-5p on experimental optic neuritis and mechanism. Methods: Female C57BL/6 mice were utilized to establish the EAE model. miR-216b-5p expression was measured by RT-qPCR. Protein expression was evaluated via western blot. Inflammatory infiltration score was analyzed by HE staining. Visual function was assessed by measuring the OKR. Flow cytometry assay was conducted to measure the percentage of IL-17 cells. ELISA was utilized to evaluate the immune factor. Results: The EAE mouse model was successfully established. The EAE score of mice began to increase in EAE group after 11 days of MOG35-55 and CFA immunization. The degree of inflammatory cell infiltration in EAE mice was higher than that in normal mice. Compared with normal mice, the number of microglia and astrocytes was raised in EAE mice. miR-216b-5p expression was obviously declined and FAS expression was obviously raised in EAE. Compared with NC group, demyelination scores and axonal loss were markedly declined in miR-216b-5p mimic group. IL-17A concentration and the percentage of IL-17 cells were obviously declined in miR-216b-5p mimic group. FAS was predicted to be regulated by miR-216b-5p by TargetScan, and luciferase reporter assay confirmed this prediction. In addition, overexpression of FAS exacerbated experimental optic neuritis by promoting the inflammatory response and Th17 cell differentiation, and miR-216b-5p reversed this effect. Conclusions: miR-216b-5p downregulated FAS and inhibited the progression of experimental optic neuritis via promoting the inflammatory response and Th17 cell differentiation.

PM2.5 Exposure of Mice during Spermatogenesis: A Role of Inhibitor κB Kinase 2 in Pro-Opiomelanocortin Neurons.

BACKGROUND: Epidemiological studies have shown that exposure to ambient fine particulate matter with aerodynamic diameter less than or equal to 2.5 µm (PM2.5) correlates with a decrease in sperm count, but the biological mechanism remains elusive. OBJECTIVES: This study tested whether hypothalamic inflammation, an emerging pathophysiological mediator, mediates the development of lower epididymal sperm count due to PM2.5 exposure. METHODS: Inhibitor κB kinase 2 (IKK2) was conditionally knocked out either in all neurons or subtypes of hypothalamic neurons of mice. Effects of concentrated ambient PM2.5 (CAP) exposure on hypothalamic inflammation, the hypothalamic-pituitary-gonadal (HPG) axis, and epididymal sperm count of these mouse models were then assessed. Furthermore, to test whether hypothalamic inflammation is sufficient to decrease sperm production, we overexpressed constitutively active IKK2 (IKK2ca) either in all neurons or subtypes of hypothalamic neurons and assessed hypothalamic inflammation, the HPG axis, and sperm production of these overexpression mouse models. RESULTS: CAP-exposed wild-type control mice vs. filtered air (FA)-exposed wild-type control mice had a higher expression of hypothalamic inflammatory markers, lower functional indexes of the HPG axis, and a lower epididymal sperm count. In contrast, all these measurements for CAP- vs. FA-exposed mice deficient of IKK2 in all neurons were comparable. We also found that overexpression of IKK2ca in either all neurons or pro-opiomelanocortin (POMC) neurons only, but not in Agouti-related protein (AgRP) neurons only, resulted in lower functional indexes of the HPG axis and a lower epididymal sperm count. Moreover, we showed that CAP- vs. FA-exposed mice deficient of IKK2 in POMC neurons had a comparable expression of hypothalamic inflammatory markers, comparable functional indexes of the HPG axis, and a comparable epididymal sperm count. DISCUSSION: This mouse model study shows a causal role of IKK2 of POMC neurons in the development of lower epididymal sperm count due to PM2.5 exposure, providing a mechanistic insight into this emerging pathogenesis. https://doi.org/10.1289/EHP8868.

Hierarchical porous structured polysulfide supported nZVI/biochar and efficient immobilization of selenium in the soil.

Soil pollution with selenium is a significant environmental problem in several areas of the world, which extremely affects the growth of plants and human health. Thus, it is necessary to find an effective method to immobilize selenium in the soil to make it less bioavailable and less accessible. In this study, the low-cost biochar-supported nanoscale zero-valent iron and polysulfide (PS-nZVI@BC) are produced and used for the immobilization of selenium (Se) in soil. The FTIR, UV-Vis, XRD, VSM, SEM and XPS techniques validate surface properties and morphology of PS-nZVI@BC. Introduction of S2- led to the in-situ formation of FeS on the surface of the biochar supported zero valent iron. Two intense Bragg peaks (2θ) of 40.5°, 44.5° were corresponded to Fe0 basal plane, indicating the presence of nZVI in nZVI@BC and PS-nZVI@BC. The modified biochar presents a magnetic saturation value of 0.008 emu/mg, reasonably less than the reported values of bare nZVI. The soil immobilization showed that the PS-nZVI@BC is more effective for the control of selenium than the biochar and nZVI@BC. The available selenium content decreased by 77.29% in PS-nZVI@BC amended soil after 30 days. From sequential extraction procedure (SEP) results, it was observed that PS-nZVI@BC promoted the conversion of more accessible Se (water-soluble and exchangeable fractions) into the less accessible forms (acid-soluble, organic, and residual fractions) to reduce the toxicity of Se. Surface sorption, reduction and complexation were dominant mechanisms for Se immobilization. Hence, PS-nZVI@BC is promising and effective for immobilizing Se in contaminated soils and improving the soil properties.

Novel mulberry silkworm cocoon-derived carbon dots and their anti-inflammatory properties.

Mulberry silkworm cocoon (MSC) carbonisata has been used for the treatment of inflammatory diseases for hundreds of years; however, after years of research efforts, little information is available on its anti-inflammatory components and underlying mechanism. We developed novel carbon dots (CDs) derived from MSC carbonisata (MSC-CDs), for the first time, with an average diameter of 2.26-9.35 nm and a quantum yield (QY) of 6.32%. The MSC-CDs were prepared using a modified pyrolysis method, and no further modification and external surface passivation agent was required. With abundant surface groups, MSC-CDs showed distinct solubility and bioactivity. In this study, we innovatively used three classical experimental models of inflammation to evaluate the anti-inflammatory bioactivity of MSC-CDs. The results indicated that MSC-CDs exhibited marked anti-inflammatory bioactivity which was likely mediated by inhibition of the expression of interleukin-6 and tumour necrosis factor-α. These results suggest that MSC-CDs possess a remarkable anti-inflammatory property, which provides evidence to support further investigation of the considerable potential and effective material basis of this traditional Chinese medicine.

Antihyperuricemic and anti-gouty arthritis activities of Aurantii fructus immaturus carbonisata-derived carbon dots.

Aim: To explore the antihyperuricemia and anti-gouty arthritis activities of Aurantii fructus immaturus carbonisata-derived carbon dots (AFIC-CDs). Materials & methods: The AFIC-CDs were characterized using transmission electron microscopy; high-resolution transmission electron microscopy; ultraviolet, fluorescence, Fourier-transform infrared and x-ray photoelectron spectroscopy; high-performance liquid chromatography; and x-ray diffraction. Antihyperuricemia and anti-gouty arthritis activities of AFIC-CDs were explored in vivo and in vitro. Results: The AFIC-CDs diameter ranged from 1.1 to 4.4 nm, with a yield of 7.2%. AFIC-CDs reduced serum uric acid by inhibiting xanthine oxidase activity in hyperuricemia rats and inhibited xanthine oxidase activity in vitro. AFIC-CDs improved gouty arthritis induced by monosodium urate crystals in vivo and in vitro. Conclusion: AFIC-CDs may be a potential treatment for gout.

The Effects of Pavement Types on Soil Bacterial Communities across Different Depths.

Pavements have remarkable effects on topsoil micro-organisms, but it remains unclear how subsoil microbial communities respond to pavements. In this study, ash trees (Fraxinus Chinensis) were planted on pervious pavement (PP), impervious pavement (IPP), and non-pavement (NP) plots. After five years, we determined the soil bacterial community composition and diversity by high-throughput sequencing of the bacterial 16S rRNA gene. The results of our field experiment reveal that the presence of pavement changed soil bacterial community composition and decreased the Shannon index, but had no impact on the Chao 1 at the 0-20 cm layer. However, we achieved the opposite result at a depth of 20-80 cm. Furthermore, there was a significant difference in bacterial community composition using the Shannon index and the Chao 1 at the 80-100 cm layer. Soil total carbon (TC), total nitrogen (TN), available phosphorus (AP), NO3--N, and available potassium (AK) were the main factors that influenced soil bacterial composition and diversity across different pavements. Soil bacterial composition and diversity had no notable difference between PP and IPPs at different soil layers. Our results strongly indicate that pavements have a greater impact on topsoil bacterial communities than do subsoils, and PPs did not provide a better habitat for micro-organisms when compared to IPPs in the short term.

Transport pathway and source area for Artemisia pollen in Beijing, China.

Artemisia pollen is an important allergen responsible for allergic rhinitis in Beijing, China. To explore the transport pathways and source areas of Artemisia pollen, we used Burkard 7-day traps to monitor daily pollen concentrations in 2016 in an urban and suburban locality. Backward trajectories of 24- and 96-h and their cluster analysis were performed to identify transport pathways of Artemisia pollen using the HYSPLIT model on 0.5° × 0.5° GADS meteorological data. The potential source contribution function (PSCF) and concentration weighted trajectory (CWT) were calculated to further identify the major potential source areas at local, regional, and long-range scales. Our results showed significant differences in Artemisia pollen concentration between urban and suburban areas, attributed to differences in plant distribution and altitude of the sampling locality. Such differences arisen from both pollen emission and air mass movements, hence pollen dispersal. At local or regional scales, source area of northwestern parts of Beijing City, Hebei Province and northern and northwestern parts of Inner Mongolia influenced the major transport pathways of Artemisia pollen. Transport pathway at a long-range scale and its corresponding source area extended to northwestern parts of Mongolia. The regional-scale transport affected by wind and altitude is more profound for Artemisia pollen at the suburban than at the urban station.

Programming of mouse obesity by maternal exposure to concentrated ambient fine particles.

BACKGROUND: Many diseases including obesity may originate through alterations in the early-life environment that interrupts fetal development. Increasing evidence has shown that exposure to ambient fine particles (PM2.5) is associated with abnormal fetal development. However, its long-term metabolic effects on offspring have not been systematically investigated. RESULTS: To determine if maternal exposure to PM2.5 programs offspring obesity, female C57Bl/6j mice were exposed to filtered air (FA) or concentrated ambient PM2.5 (CAP) during pre-conception, pregnancy, and lactation, and the developmental and metabolic responses of offspring were assessed. The growth trajectory of offspring revealed that maternal exposure to CAP significantly decreased offspring birth weight but increased body weight of adult male but not female offspring, and the latter was expressed as increased adiposity. These adult male offspring had increased food intake, but were sensitive to exogenous leptin. Their hypothalamic expression of Socs3 and Pomc, two target genes of leptin, was not changed, and the hypothalamic expression of NPY, an orexigenic peptide that is inhibited by leptin, was significantly increased. These decreases in central anorexigenic signaling were accompanied by reduced plasma leptin and its expression in adipose tissues, the primary source of circulating leptin. In contrast, maternal exposure did not significantly change any of these indexes in adult female offspring. Pyrosequencing demonstrated that the leptin promoter methylation of adipocytes was significantly increased in CAP-exposed male but not female offspring. CONCLUSIONS: Our data indicate that maternal exposure to ambient PM2.5 programs obesity in male offspring probably through alterations in the methylation of the promoter region of the leptin gene.

[Seasonal Dynamics of Airborne Pollens and Its Relationship with Meteorological Factors in Beijing Urban Area].

The seasonal dynamics of airborne pollens and their relationship with meteorological conditions, which are considered to be important factors for appropriate construction of urban green system and reliable prevention of tropic pollinosis, were investigated in Beijing urban area. The airborne pollens were monitored from December 31st 2011 to December 31st 2012 by Burkard volumetric trap, and the data were analyzed. The results revealed that: (1) In 2012 the pollen dispersion period lasted 238 days from March 17 to November 18th, accounting for 65% of the year. There were two peaks of pollen amount in air, which occurred from March to May and from August to October, respectively. In the spring peak, tree pollens such as Oleaceae, Populus and Salix pollens were the dominant, accounting for 53% of the total annual pollens, while in the autumn period, weed pollens such as Compositae, Chenopodiaceae and Amaranthaceae pollens made up about 40% of the annual total value; (2) The highly allergenic weeds pollens dominated in autumn, which caused a high incidence of tropic pollinosis; (3) The airborne pollen amount of Beijing urban area was significantly affected by meteorological condition like the wind speed, temperature, humidity, precipitation and so on; (4) When temperature ranged from OC to 15 degrees C, the pollen amount showed positive relation with temperature; while in the temperature range of 18 degrees C to 30 degrees C, it showed negative relation; (5) The average temperature of spring and autumn season in 2012 was 17 degrees C, and 79% of airborne pollens were detected in these two seasons. This temperature condition was conducive to the pollen dispersion. (6) The pollen amount showed negative relation with relative moisture between 20% and 50% and larger than 70%, while in the moisture range of 50% to 60%, it showed positive relation; (7) The wind speed smaller than 3 m x s(-1) was good to pollen distribution, when it was larger than 4 m x s(-1) or the wind lasted for a long time, the pollen amount in the air would decrease; (8) The pollen release was decreased by the rain. The above results can be helpful to forecast the pollen amount in the air. monitoring; pollen amount

[Characteristics of Total Nitrogen and Total Phosphorus Pollution and Eutrophication Assessment of Secondary River in Urban Chongqing].

To understand the secondary river quality in Chongqing urban area, six typical secondary rivers were chosen to investigate the pollution characteristics of total nitrogen and total phosphorus and to evaluate the water eutrophication level according to the monitoring data of water physicochemical characteristics and chlorophyll content from April 2013 to March 2014. The study results showed that: the six rivers mentioned above have been seriously polluted by TN and TP, with the monthly mean values of TN and TP far exceeding the universally accepted threshold values of water eutrophication. Water eutrophicaton appraisal result indicated that all rivers in each season were in a state of eutrophication, and the eutrophication level could be arranged in the order of Panxi River > Qingshui River > Tiaodeng River > Huaxi River > Funiu River > Chaoyang River. The seasonal changes in TN and TP of secondary rivers were significant, with high concentrations of TN and TP in spring and winter, and lower concentrations in summer and autumn. TN and TP of the rivers showed a trend of increasing from the upstream to the downstream in each season. Pollutant concentration accumulated gradually along rivers and the maximum accumulation rate reached 1. 25 mg . (L . km) -1. Therefore, further study on urban secondary river pollution characteristics is of great significance to urban water pollution control.

Nitrogen and phosphorus associating with different size suspended solids in roof and road runoff in Beijing, China.

Roofs and roads, accounting for a large portion of the urban impervious land surface, have contributed significantly to urban nonpoint pollution. In this study, in Beijing, China, roof and road runoff are sampled to measure the suspended solids (SS), nitrogen (N), and phosphorus (P) contained in particles with different sizes. The SS content in the road runoff (151.59 mg/L) was sevenfold that in the roof runoff (21.13 mg/L, p < 0.05). The SS contained more coarse particulates in the roof runoff than in road runoff. The small particulates in the range of 0.45-50 µm consisted of 59 % SS in the roof runoff and 94 % SS in the road runoff. P was mainly attached to particle sizes of 10-50 µm in the roof (73 %) and road (48 %) runoffs, while N was mainly in a dissolved phase state in both runoffs. So, the different associations of N and P raise a challenge in preventing stormwater pollution in urban environments.

Exposure to concentrated ambient particulate matter induces reversible increase of heart weight in spontaneously hypertensive rats.

BACKGROUND: Exposure to ambient PM2.5 increases cardiovascular mortality and morbidity. To delineate the underlying biological mechanism, we investigated the time dependence of cardiovascular response to chronic exposure to concentrated ambient PM2.5 (CAP). METHODS: Spontaneously hypertensive rats (SHR) were exposed to CAP for 15 weeks, and blood pressure (BP), cardiac function and structure, and inflammations of lung, hypothalamus, and heart were measured at different time points. RESULTS: Chronic exposure to CAP significantly increased BP, and withdrawal from CAP exposure restored BP. Consistent with its BP effect, chronic exposure to CAP significantly decreased cardiac stroke volume and output in SHR, accompanied by increased heart weight and increased cardiac expression of hypertrophic markers ACTA1 and MYH7. Withdrawal from CAP exposure restored cardiac function, weight, and expression of hypertrophic markers, supporting the notion that cardiac dysfunction and hypertrophy is subsequent to hypertension. In agreement with the role of systemic inflammation in mediating the cardiovascular effects of CAP exposure, chronic exposure to CAP markedly increased expression of pro-inflammatory cytokines in lung, heart, and hypothalamus. However, withdrawal from exposure resolves inflammation in the heart and hypothalamus, but not in the lung, suggesting that CAP exposure-induced systemic inflammation may be independent of pulmonary inflammation. CONCLUSION: Chronic exposure to CAP induces reversible cardiac dysfunction and hypertrophy, which is likely to be subsequent to the elevation in BP and induction of systemic inflammation as evidenced by increased mRNA expression of pro-inflammatory cytokines in diverse tissues.

[Characterization of Pollutant Wash-off in the Urban Stormwater].

To understand the pollution character of urban road runoff, the concentrations of TSS, EC, N and P in the ring road runoff of Beijing from June to September 2013 were evaluated, the correlations among pollutants were examined, and the load of TSS, N and P were estimated. Result showed that the small particulates in the range of 1-10 µm consisted of 60% TSS in the road runoff. Totally 89 percent of the nitrogen (N) was dissolved phase state in the road runoff, 80 percent of the phosphorus (P) was particular phase state in the road runoff. Based on the characteristics of correlations between EC, TSS and TN, TP, EC and TSS were the surrogate indexes of pollution degree assessment for the dissolved N and particulate P in the urban road runoff, respectively. Based on our results, the SS, N and P year load per unit area in Beijing ring road runoff were 16 725.69, 1777.91 and 24.23 mg x (m2 x a)(-1), respectively. Our findings described the polutant wash off character in urban road runoff, which provide a scientific basis for management of nonpoint pollution in a city and an alternative method for controlling pollution.

The temporal changes in road stormwater runoff quality and the implications to first flush control in Chongqing, China.

This study investigates the quality of stormwater runoff from a driveway in the southwest mountainous urban area of Chongqing, China, from 2010 to 2011. The results showed that the mean concentrations of chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP) were 4.1, 2.4, and 2.2 times the grade V levels of the national surface water standard of China. The pollutant concentration peak preceded or synchronized with the rainfall intensity peak and occurred 10 min after the runoff started. The significant high pollutant concentration in the initial stage of the rainfall suggested that first flush control is necessary, especially for the most polluted constitutes, such as total suspended solids, COD, and TN. Three potential pollution sources were identified: the atmospheric dry and wet deposition (TN, NO3(-)-N, NH4(+)-N, and DCu), the road sediment and materials (total suspended solids, COD, and TP), and the vehicle emissions (DPb and DZn). Therefore, this study indicates that reductions in road sediments and material pollution and dry and wet deposition should be the priority factors for pollution control of road stormwater runoff in mountainous urban areas.

Differential effects of high-fat-diet rich in lard oil or soybean oil on osteopontin expression and inflammation of adipose tissue in diet-induced obese rats.

PURPOSE: To examine the effect of different dietary fat types on osteopontin (OPN) expressions and inflammation of adipose tissues in diet-induced obese rats. METHODS: Male Sprague-Dawley rats were randomly assigned to one control group fed standard diet (LF, n = 10) and two high-fat diet groups fed isoenergy diet rich in lard or soybean oil (HL or HS, n = 45 each). Diet-induced obese rats in HL and HS group were then subdivided into two groups either continuously fed high-fat diet or switched to low-fat diet for 8 more weeks. Fasting serum glucose, insulin, and OPN concentrations were assayed and QUICKI was calculated; the expression of OPN, IL-6, IL-10, TNF-α, NF-κB, and F4/80 in adipose tissue was determined. RESULTS: Both high-fat diets lead to comparable development of obesity characterized by insulin resistance and adipose tissue inflammation. Obese rats continuously fed high-fat diet rich in lard oil exhibited the highest fasting serum insulin level and adipose tissue OPN, F4/80, TNF-α, and NF-κB expression level. In both high-fat diet groups, switching to low-fat diet resulted in less intra-abdominal fat mass, decreased expression of F4/80, TNF-α, and NF-κB, while decreased OPN expression was only observed in lard oil fed rats after switching to low-fat diet. CONCLUSIONS: Reducing diet fat or replacing lard oil with soybean oil in high-fat diet alleviates obesity-related inflammation and insulin resistance by attenuating the upregulation of OPN and macrophage infiltration into adipose tissue induced by high-fat diet.

Increased hypothalamic inflammation associated with the susceptibility to obesity in rats exposed to high-fat diet.

Inflammation has been implicated in the hypothalamic leptin and insulin resistance resulting defective food intake during high fat diet period. To investigate hypothalamic inflammation in dietary induced obesity (DIO) and obesity resistant (DIO-R) rats, we established rat models of DIO and DIO-R by feeding high fat diet for 10 weeks. Then we switched half of DIO and DIO-R rats to chow food and the other half to high fat diet for the following 8 weeks to explore hypothalamic inflammation response to the low fat diet intervention. Body weight, caloric intake, HOMA-IR, as well as the mRNA expression of hypothalamic TLR4, NF-κB, TNF-α, IL-1ß, and IL-6 in DIO/HF rats were significantly increased compared to DIO-R/HF and CF rats, whereas IL-10 mRNA expression was lower in both DIO/HF and DIO-R/HF rats compared with CF rats. Switching to chow food from high fat diet reduced the body weight and improved insulin sensitivity but not affecting the expressions of studied inflammatory genes in DIO rats. Take together, upregulated hypothalamic inflammation may contribute to the overeating and development of obesity susceptibility induced by high fat diet. Switching to chow food had limited role in correcting hypothalamic inflammation in DIO rats during the intervention period.

[Determination of ephedrine hydrochloride, pseudoephedrine hydrochloride and methylephedrine hydrochloride in maxingshigan decoction by CE].

OBJECTIVE: To establish the method for determination of ephedrine hydrochloride, pseudoephedrine hydrochloride and methylephedrine hydrochloride in maxingshigan decoction by capillary electrophoresis. METHODS: The separation was performed on a fused silica capillary of 60 cm x 55 microcrpm ID (52 cm of effective length). 60 mmol/L NaB4O7 + 10% (V/V) CH3OH (pH 9.0) was selected as the running buffer. The separation voltage was 12 kV. The samples was injected by gravity (10 s, 15 cm). The detection wavelength was 210 nm and berberine hydrochloride was the internal standard. RESULTS: The linear range of determination for ephedrine hydrochloride, pseudoephedrine hydrochloride and methylephedrine hydrochloride were 20.0-160.0 microg/mL (r = 0.9999), 7.5-60.0 microg/mL (r = 0.9991) and 2.0-10.0 microg/mL (r = 0.9993). The average recoveries were 98.0%, 97.0% and 97.8%, the precisions of the method were 2.31%, 2.21% and 2.00% (n=6), respectively. CONCLUSION: The method is convenient, rapid and accurate for the quality control of maxingshigan decoction.

[Species composition, distribution and phenological characters of pollen-allergenic plants in Beijing urban area].

In order to know the species composition, distribution pattern, and phenological characteristics of pollen-allergenic plants in Beijing urban area, an investigation was made, combined with literature survey and experts interviews. The results showed that within the fifth ring of Beijing, there were 99 pollen-allergenic plant species belonging to 32 genera and 19 families, among which, 52 species were native plants, accounting for 52.5% of the total, 26 species were introduced from other regions of China, occupying 26.3% of the total, and 21 species were introduced from foreign countries, being 21.2% of the total. The 32 genera of pollen-allergenic plants in Beijing urban area were mainly North Temperate elements, occupying 40.6% , followed by Cosmopolitan and Pantropic elements. In all functional sections of Beijing urban area, the pollen-allergenic plants were most diversified in urban parks, and had the highest proportion in street tree species. The coverage of herbs with strong pollen allergy was in the order of waste lands > gym centers and institution yards > greenbelts > parks > residential areas > squares. The blooming period of pollen-allergenic arbors in Beijing urban area was concentrated in March and April, while that of pollen-allergenic herbs was from July to September.