Clustering Analysis of Natural D-borneol Resource Plants Based on Simple Sequence Repeat (SSR) Markers, Leaf Morphology, and Chemical Composition.

D-borneol is a double-loop monoterpene with a wide use in the pharmaceutical, food, and cosmetics industries. Natural D-borneol can be extracted from branches and leaves of D-borneol resource plants. With the widespread use of natural D-borneol, the identification of D-borneol resource plants and the protection of germplasm resources have become the focus of research. In this study, plant leaf morphology, chemical composition, and simple sequence repeat (SSR) molecular marker analysis were used to analyze and cluster 5 species of D-borneol resource plants and their closely related species. It was found that all three analysis methods could distinguish and cluster these D-borneol resource plants to some degree. The result of SSR analysis using capillary electrophoresis was the best, and it could distinguish Mei Pian tree from Yin Xiang as well as Longnao Zhang from An Zhang. The correlation analysis between SSR similarity matrix and leaf morphology analysis and between SSR similarity matrix and chemical composition similarity matrix revealed that they both had significant correlations (P < 0.0001) and the correlation (r = 0.588) between SSR and leaf morphology was a little higher than that (r = 0.519) between SSR and chemical composition. This indicated that the environment had a greater impact on the chemical composition than on leaf morphology. The research findings will offer efficient techniques to cluster natural D-borneol resource plants and establish a theoretical basis for their future development and utilization.

Bisphenol chemicals in colostrum from Shanghai, China during 2006-2019: Concentration, temporal variation, and potential influence on birth parameters.

Bisphenol A (BPA) and its alternatives bisphenol S (BPS) and bisphenol F (BPF) are identified as endocrine disruptors that have negative impacts on infant growth. Their temporal variations in human milk and potential effects on fetal growth are not well known. In this study, colostrum collecting at four time points between 2006 and 2019 and paired urine in 2019 from Shanghai, China, were analyzed for eight bisphenols. The total concentrations in colostrum in 2019 were up to 3.43 ng/mL, with BPA being dominant, followed by BPS and BPF. BPA levels in colostrum noticeably decreased from 2010 to 2013. Additionally, obvious percentage changes in bisphenols were observed in 2019. The BPA concentrations in paired colostrum and urine were not significantly correlated. High levels of BPA in colostrum were linked to a significant reduction in birth head circumference in 2019 (p = 0.031). BPA and BPS in colostrum might have similar negative effect on fetal growth in 2019, but these effects were generally non-significant. Further studies are needed to testify the potential impact. The hazard indexes for infants in the first week of life were below 1, suggesting no obvious health risks. However, the high contribution from BPA still warrants further attention.

In Vitro Profiling of Toxicity Effects of Different Environmental Factors on Skin Cells.

The skin is constantly exposed to a variety of environmental threats. Therefore, the influence of environmental factors on skin damage has always been a matter of concern. This study aimed to investigate the cytotoxic effects of different environmental factors, including cooking oil fumes (COFs), haze (PM2.5), and cigarette smoke (CS), on epidermal HaCaT cells and dermal fibroblast (FB) cells. Cell viability, intracellular reactive oxygen species (ROS) generation, inflammatory cytokine levels, and collagen mRNA expression were used as toxicity endpoints. Additionally, the effects of ozone (O3) on cell viability and release of inflammatory cytokines in 3D epidermal cells were also examined. The results showed that the organic extracts of CS, COFs, and PM2.5 significantly inhibited the viability of HaCaT and FB cells at higher exposure concentrations. These extracts also increased intracellular ROS levels in FB cells. Furthermore, they significantly promoted the release of inflammatory cytokines, such as IL-1α and TNF-α, in HaCaT cells and down-regulated the mRNA expression of collagen I, III, IV, and VII in FB cells. Comparatively, SC organic extracts exhibited stronger cytotoxicity to skin cells compared to PM2.5 and COFs. Additionally, O3 at all test concentrations significantly inhibited the viability of 3D epidermal cells in a concentration-dependent manner and markedly increased the levels of TNF-α and IL-1α in 3D epidermal cells. These findings emphasize the potential cytotoxicity of COFs, PM2.5, CS, and O3 to skin cells, which may lead to skin damage; therefore, we should pay attention to these environmental factors and take appropriate measures to protect the skin from their harmful effects.

Enhancing UV-C Photoelectron Lifetimes for Avalanche-like Photocurrents in Carbon-Doped Bi3O4Cl Nanosheets.

Interlayer electric fields in two-dimensional (2D) materials create photoelectron protecting barriers useful to mitigate electron-hole recombination. However, tuning the interlayer electric field remains challenging. Here, carbon-doped Bi3O4Cl (C:Bi3O4Cl) nanosheets are synthesized using a gas phase protocol, and n-type carriers are acquired as confirmed by the transconductance polarity of nanosheet field effect transistors. Thin C:Bi3O4Cl nanosheets show excellent 266 nm photodetector figures of merit, and an avalanche-like photocurrent is demonstrated. Decaying behaviors of photoelectrons pumped by a 266 nm laser pulse (266 nm photoelectrons) are observed using transient absorption spectroscopy, and a significant 266 nm photoelectron lifetime quality in C:Bi3O4Cl is presented. Built C:Bi3O4Cl models suggest that the interlayer electric field can be boosted by two different carbon substitutions at the inner and outer bismuth sites. This work reports a facile approach to increase the interlayer electric field in Bi3O4Cl for future UV-C photodetector applications.

In Silico Genome-Wide Mining and Analysis of Terpene Synthase Gene Family in Hevea Brasiliensis.

Terpene synthases (TPSs) catalyze terpenoid synthesis and affect the intracellular isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP) concentration. In this study, we mined the in silico genome-wide TPS genes of Hevea brasiliensis and identified 47 full-length TPS genes. They had DDXXD, DXDD, NSE/DTE, RR(X)8 W, EA(X)W, and other conserved motifs. The phylogenetic tree analysis revealed that the TPSs of H.brasiliensis (HbTPSs) were divided into five subfamilies, TPS-a, TPS-b, TPS-c, TPS-e/f, and TPS-g. HbTPSs were predicted to have functions in the cellular components, molecular functions, and biological processes. HbTPSs were involved in seven pathways, which were K14173, K14175, K15803, K04120, K04121, K17982, and K12742 in the secondary metabolite pathway prediction. Three-dimensional structures of HbTPSs of 7 pathways were predicted, and DDXXD, NSE/DTE, and EA(X)W conserved motifs near the binding sites were found. Cis-acting elements analysis showed that they had more cis-acting elements related to phytohormone responsiveness, which indicated that terpenoid biosynthesis might be related to phytohormone regulation. RNA-Seq analysis showed that different HbTPSs were expressed differentially in different tissues. This study's results help reveal the role of HbTPSs and their molecular mechanism and help resolve the regulatory mechanism of terpenoid biosynthesis in H.brasiliensis.

Organophosphate tri- and diesters in source water supply and drinking water treatment systems of a metropolitan city in China.

The water contaminations with organophosphate triesters (tri-OPEs) and diesters (di-OPEs) have recently provoked concern. However, the distributions of these compounds in natural water sources and artificial water treatment facilities are poorly characterized. A comprehensive study was therefore performed to measure their concentrations in a water source, a long-distance water pipeline, and a drinking water treatment plant (DWTP). Eight tri-OPEs and 3 di-OPEs were found to be widely distributed, with total concentrations in source water and pipelines ranging from 290.6 to 843.9 ng/L. The most abundant pollutants were tris(1-chloro-2-propyl) phosphate (TCPP), triethyl phosphate, tri-n-butyl phosphate (TnBP), and diphenyl phosphate (DPhP). Di-OPEs appeared to be removed less efficiently in the DWTP than the parent tri-OPEs, and the elimination efficiencies of tri-OPEs were structure-dependent. Long-distance pipeline transportation had no significant effect on the distributions of tri- and di-OPEs. Statistical analysis suggested that the sources of di-OPEs and the corresponding tri-OPEs differed, as did those of DPhP and di-n-butyl phosphate. A risk analysis indicated that tri-OPEs present limited ecological risks that are mainly due to TnBP and TCPP, and that the human health risks of tri-OPEs are negligible. However, di-OPEs (especially DPhP) may increase these risks. Further studies on the risks posed by di-OPEs in aquatic environments are therefore needed.

Full-Length Transcriptome Sequencing Combined with RNA-Seq to Analyze Genes Related to Terpenoid Biosynthesis in Cinnamomum burmannii.

Cinnamomum burmannii is a cinnamomum plant rich in natural D-borneol. Natural D-borneol is a bicycle monoterpenoid compound widely used in the food, pharmaceutical, and cosmetic industries. Therefore, analyzing the biosynthesis mechanism of natural D-borneol in C. burmannii at the molecular level is helpful for directional breeding in the future and further development and utilization of C. burmannii and its related gene resources. In our study, 76 genes related to terpene metabolism were analyzed through third-generation sequencing and second-generation sequencing. Of these genes, 57 were associated with the synthesis of the terpenoid skeleton, and 19 belonged to terpenoid synthase, including four monoterpenoid synthases, seven sesquiterpenoid synthases, and eight diterpenoid synthases. Two genes in diterpenoid synthase were differentially expressed in high D-borneol and low D-borneol plants. It was speculated that these two genes might be related to D-borneol synthesis. How these two genes participate in the synthesis of D-borneol needs further study.

Elastic mechanics solution of thermal expansion of bi-material curved beam and its application to negative thermal expansion metamaterials.

Thermal stress impacts various engineering fields significantly, such as aerospace and precision instruments. This adverse effect can be greatly reduced, if not eliminated, by the application of micro-thermal expansion materials, and bi-material beams are widely utilized in the design of micro-thermal expansion structures, thereby exhibiting great application potentials. The elasticity solution of bi-material curved beam under free thermal expansion has been proposed by scholars. Based on this solution, the simplified form is proposed in this paper, and extended to the case where the rotation angles at both ends of the circular arc are constrained under thermal loads. Besides, the geometric parameters and the nonlinear problems of the thermal expansion of bi-material curved beam are analyzed. In addition, a novel type of negative thermal expansion material has been designed by applying the bi-material curved beam to the tetra chiral and anti-tetra chiral materials. The proposed material has greater negative thermal expansion effect than the traditional tetra and anti-tetra chiral materials that are with straight beams.

Does City Public Service Distance Increase Sense of Gain to Public Health Service? Evidence from 1394 Migrant Workers in Six Provinces.

Increasing the well-being of migrant workers is one of the key objectives of promoting equality and safe, people-oriented, and sustainable social development, as well as inclusive globalization. With the equalization reform of the public health system and the reduction of frictions between cities, the well-being of the sense of gain to public health service (SGPHS) of migrant workers has attracted widespread attention. Based on the migrant worker thematic survey data in 2017 and the city statistical data in six destination cities, this study constructed and measured the sense of gain to public health service index and city public service distance index, and then studied the effects of city public service distance on the SGPHS of migrant workers and the heterogeneous effect. The results showed that the SGPHS of Chinese migrant workers is at a moderate level and presents spatial differences. Under the dual mechanism of preference reinforcement effect and public service discount effect, the effect of city public service distance on the SGPHS of migrant works shows an inverted U-shaped relationship, and the results of the endogeneity test by the generalized propensity score matching model are robust. The city public service distance has a significant non-linear effect on the public health service accessibility and provision for migrant workers, as well as on second-generation, low-income migrant workers, and migrant workers in central and western regions. The results provide beneficial insights for the formulation of rational public service policies.

Interaction between bacterial diversity and biogenic amines production in a salted mackerel stored at soft frozen (-7℃-0℃) storage.

The bacterial diversity of salted mackerel "one-night courtyard" at soft frozen area (-7℃-0℃) storage was studied. The fish samples at 0, 14, 21, 28, and 35 days were analysis for bacterial structure using high-throughput sequencing technologies (HTS) and biogenic amines using high-performance liquid chromatography (HPLC). The analysis results of HTS showed that the dominant bacteria species was varied gradually following with storage time. On the 0th, 21st, and 28th days of storage, dominant Vibrionaceae was accounting for 71.70%, 59.16%, and 70.68% of the total sequences analyzed, respectively. On the 14th and 35th days, Shewanellaceae was the dominant bacterial, accounting for 87.53% and 70.95% of the total sequences analyzed, respectively. In addition, 21st and 28th days, an abundance of Operational Taxonomic Units (OTUs) was top. The dominant bacterial of Proteobacteria, Firmicutes, was producer of biogenic amines. Furthermore, the analysis results of HPLC shown the total biogenic amines of maximum amount 363.01 mg/kg in the sample of HY.14 lower than 1000 mg/kg of the FDA regulation. The range ability of cadaverine was obvious following with the storage time. Cadaverine was 87.36 mg/kg on the 0th day, and it was maximum amount of 276.89 mg/kg on the 14th days. Putrescine was 20 mg/kg on the 0th day and maximum amount of 55.04 mg/kg on the 28thdays of storage. The tyramine was smallest amount of production, and the largest amount was 38.99 mg/kg on 28th, and the smallest amount was 11.97 mg/kg on 35th. Nevertheless, the maximum amount of histamine was 55.04 mg/kg on the 0th day and about 23.14 mg/kg of histamine was little change from 14th to 35th days of storage. Dominant bacteria affect the change of biogenic amines. The study can help understand the interaction between microbial flora and biogenic amines in the salted mackerel of one-night courtyard.

Recent Advances in Phage-Based Therapeutics for Multi-Drug Resistant Acinetobacter baumannii.

Acinetobacter baumannii is an important opportunistic pathogen common in clinical infections. Phage therapy become a hot research field worldwide again after the post-antibiotic era. This review summarizes the important progress of phage treatments for A. baumannii in the last five years, and focus on the new interesting advances including the combination of phage and other substances (like photosensitizer), and the phage encapsulation (by microparticle, hydrogel) in delivery. We also discuss the remaining challenges and promising directions for phage-based therapy of A. baumannii infection in the future, and the innovative combination of materials in this area may be one promising direction.

[Cloning and expression pattern of phosphate transporter 1;1 cDNA sequence from Spirodela polyrrhiza].

Spirodela polyrrhiza is a floating plant widely used in biomass utilization and eutrophication phytoremediation. It becomes a common aquatic plant everywhere with the increasingly serious eutrophication. It has been reported that S. polyrrhiza has a good effect on the remediation of eutrophication water. In order to study the absorption and transportation of phosphorus in S. polyrrhiza, we extracted RNA from S. polyrrhiza and then reverse transcribed it into cDNA, which was used as a template to amplify a specific fragment. The full-length sequence of the open reading frame (ORF) was 1 620 bp, encoding 539 amino acids, named SpPHT1;1, and the accession number in GenBank was MN720003. Bioinformatical analysis showed that SpPHT1;1 had no intron. The protein it encoded was a stable, hydrophobic protein with 11 transmembrane domains. SpPHT1;1 structure was similar to that of major facilitator superfamily (MFS) superfamily members. The cluster analysis showed that SpPHT1;1 was closely related to ZMPHT2 in maize and SBPHT1-8 in sorghum. So, it might belong to plant PHT1 family. The expression of SpPHT1;1 in leaf was significantly more than that of root under normal phosphorus condition. Low phosphorus condition could promote gene expression, and the relative expression level of SpPHT1;1 arrived at the peak at 48 h both in root and leaf. High phosphorus condition could inhibit gene expression. These results indicated that SpPHT1;1 expression would be affected by external phosphorus concentration. The results of this study are helpful for further research on the function of phosphate transporter. It also can provide theoretical basis for further development and utilization of S. polyrrhiza.

A 1232 bp upstream sequence of glutamine synthetase 1b from Eichhornia crassipes is a root-preferential promoter sequence.

BACKGROUND: Glutamine synthetase (GS) acts as a key enzyme in plant nitrogen (N) metabolism. It is important to understand the regulation of GS expression in plant. Promoters can initiate the transcription of its downstream gene. Eichhornia crassipes is a most prominent aquatic invasive plant, which has negative effects on environment and economic development. It also can be used in the bioremediation of pollutants present in water and the production of feeding and energy fuel. So identification and characterization of GS promoter in E. crassipes can help to elucidate its regulation mechanism of GS expression and further to control its N metabolism. RESULTS: A 1232 bp genomic fragment upstream of EcGS1b sequence from E. crassipes (EcGS1b-P) has been cloned, analyzed and functionally characterized. TSSP-TCM software and PlantCARE analysis showed a TATA-box core element, a CAAT-box, root specific expression element, light regulation elements including chs-CMA1a, Box I, and Sp1 and other cis-acting elements in the sequence. Three 5'-deletion fragments of EcGS1b upstream sequence with 400 bp, 600 bp and 900 bp length and the 1232 bp fragment were used to drive the expression of ß-glucuronidase (GUS) in tobacco. The quantitative test revealed that GUS activity decreased with the decreasing of the promoter length, which indicated that there were no negative regulated elements in the EcGS1-P. The GUS expressions of EcGS1b-P in roots were significantly higher than those in leaves and stems, indicating EcGS1b-P to be a root-preferential promoter. Real-time Quantitative Reverse Transcription-Polymerase Chain Reaction (qRT-PCR) analysis of EcGS1b gene also showed higher expression in the roots of E.crassipes than in stems and leaves. CONCLUSIONS: EcGS1b-P is a root-preferential promoter sequence. It can specifically drive the transcription of its downstream gene in root. This study will help to elucidate the regulatory mechanisms of EcGS1b tissue-specific expression and further study its other regulatory mechanisms in order to utilize E.crassipes in remediation of eutrophic water and control its overgrowth from the point of nutrient metabolism.

[Comparison of 127° small and 135° large stem angle prostheses in total hip arthroplasty].

OBJECTIVE: To investigate the effect of total hip arthroplasty(THA) with the prosthesis of 127° small neck stem angle and 135° large neck stem angle. METHODS: From January 2014 to June 2016, 84 patients with THA were selected, including 44 males and 40 females, aged 45 to 72(53.4±8.1) years old, 68 patients with necrosis of the femoral head(32 on the left and 36 on the right), 16 patients with serious osteoarthritis of the hip caused by other reasons, and the course of disease was 9 to 36 (24.0±5.5) months. Forty-two patients in each group were evaluated by Harris score, visual analog score(VAS), length measurement of lower limbs, biomechanical evaluation of different angles of the neck stem. The complications and quality of life 24 months after operation were compared. RESULTS: Two patients in each group were lost, the rest were followed up for 30 to 36 (33.0±1.6)months. The Harris score and the length of both lower limbs were measured before and 1, 6, 12, 24 months after operation. The difference of Harris score and the length of both lower limbs in the two groups was significantly improved compared with that before operation(P<0.05), but there was no significant difference between the two groups(P>0.05). There was no significant difference between the two groups in VAS score before operation (P>0.05), but the VAS score of the group with large neck stem angle was significantly lower than that of the group with small neck stem angle(P<0.05). There was no significant difference in the incidence of postoperative complications between the two groups (P>0.05). The quality of life of the patients in the two groups after 24 months was significantly higher than that before operation (P<0.05). CONCLUSION: THA with large and small neck stem angle prosthesis can better recover the function of hip joint, but large neck stem angle can reduce the degree of postoperative pain and improve the quality of life of patients.

Enhanced extraction efficiency of natural D-borneol from Mei Pian tree leaves pretreated with deep eutectic solvents.

Stems and leaves of Mei Pian tree can be used to extract natural D-borneol. In this study, a variety of deep eutectic solvents (DESs) based on choline chloride were used to pretreat leaves of Mei Pian tree, from which natural D-borneol was extracted by Soxhlet extraction. The extraction efficiency of most pretreated leaves was higher than that of the unpretreated leaves, and that pretreated by DES based on choline chloride and sucrose or choline chloride and glycol was maximal. Moreover, The Box-Behnken design (BBD) of response surface method was used to optimize the water content, temperature, and pretreatment time. The optimal conditions included pretreatment of Mei Pian tree for 4.07 hr at 44.5°C by DES, which was synthesized using choline chloride, sucrose, and water at the molar ratio of 5:2:5.9, and the extraction efficiency (4.936 mg/g) was maximal, more than twice as much as that of unpretreatment. The results showed that the pretreatment process using DES based on choline chloride and sucrose could effectively improve the extraction efficiency of natural D-borneol from Mei Pian tree.

Effects of public health policies on the health status and medical service utilization of Chinese internal migrants.

This paper examines the effects of the "Equalization Program of Basic Public Health and Family Planning Services for Migrants" (EHFPSM), a novel internal migrant-targeted public health policy, of China implemented in 2013. By combining the individual-level data from the "China Migrants Dynamic Survey" and city-level statistical data, we find that EHFPSM contributes to a 6.9% statistically significant increase in the probability of electronic health records coverage and a 7.2% increase in the probability of reimbursement in the last inpatient visit, as well as a 1.2% decrease in the probability of one-year prevalence. The mechanism test shows that this program promotes the migrants' understanding of the policies and social insurance coverage to enhance their health status. EHFPSM brings about more significant decreases in disease prevalence for male and less-educated migrants, and higher reimbursement probability for urban hukou migrants. Our paper facilitates better understanding of the role of public health policies in promoting the internal migrants' health from the perspective of China.

Sinomenine ameliorates intervertebral disc degeneration via inhibition of apoptosis and autophagy in vitro and in vivo.

BACKGROUND: Aberrant apoptosis in nucleus pulposus (NP) cells is the primary cause of intervertebral disc degeneration (IDD). In contrast, a large number of studies have confirmed that autophagy may protect NP cells from apoptosis. Sinomenine is an alkaloid monomer, which has been reported to stimulate cell autophagy. Therefore, the aim of the present study was to investigate the effects of sinomenine on IDD. METHODS: The effects of sinomenine on the proliferation and apoptosis of NP cells were evaluated with the CCK-8 assay and Annexin V/PI staining, respectively. RESULTS: The data obtained from the present study demonstrated that sinomenine could notably reverse TBHP-induced growth inhibition and apoptosis in rat NP cells. In addition, sinomenine significantly induced autophagy in rat NP cells, which was completely inhibited by 3-methyladenine (3MA). In addition, the protective effect of sinomenine against TBHP in rat NP cells was abolished following treatment with 3MA. Finally, an in vivo study further confirmed that sinomenine could ameliorate rat IDD. CONCLUSION: Taken together, the results of the present study indicated sinomenine could ameliorate rat IDD via induction of autophagy in vitro and in vivo. These findings suggest the therapeutic potential of sinomenine in the prevention of IDD.

Rice straw pretreatment using deep eutectic solvents with different constituents molar ratios: Biomass fractionation, polysaccharides enzymatic digestion and solvent reuse.

Lignocellulosic biomass pretreatment with deep eutectic solvents (DESs) is a promising and challenging process for production of biofuels and valuable platform chemicals. In this work, rice straw was mainly fractionated into carbohydrate-rich materials (CRMs) and lignin-rich materials (LRMs) by 90% lactic acid/choline chloride (LC)-water solution with different molar ratio of hydrogen bond donor (HBD, lactic acid) and hydrogen bond acceptor (HBA, choline chloride). It was found that high HBD/HBA molar ratio of DESs was favorable for achieving CRMs and LRMs with high purity, and both HBD and HBA were responsible for effective biomass fractionation possibly due to their synergistic effect on highly efficient breakage of the linkage between hemicellulose and lignin and thus lignin extraction. About 30%-35% of lignin in native rice straw was fractionated as LRMs, and exceeding 70% of xylan were removed and fractionated into the liquid stream as forms of xylose, furfural and humins after pretreatment using aqueous LC (3:1, 5:1) solution. Consequently, polysaccharides enzymatic hydrolysis of the CRMs were significantly enhanced. Moreover, all the DESs could be recovered with high yields of around 90%, and 69% of the LC (3:1) was recovered after 5 cycles reuse at 90 °C. Besides, the recycled DES maintained a good pretreatment ability, and glucose yields of 60-70% were achieved in the enzymatic hydrolysis of CRMs obtained in each cycle. The facile process established in present work is promising for large scale production of fermentable sugars and other chemicals.

Effects of different forms of nitrogen on rhizosphere microbial community structure of Eichhornia crassipes (Pontederiaceae)

AbstractRhizosphere microbial communities are important for phytoremediation, plant nutrition, health and metabolism. Many factors, including plant species, pH and nutritional factors influence rhizosphere microbiology. In this study, we analysed the effects of different forms of nitrogen on the structures of rhizosphere microbial communities of E. crassipes. Using a conventional culture method with special media, bacteria, actinobacteria and molds were cultured. We found that the numbers of bacteria were largely similar across the three culture conditions, while the numbers of actinobacteria and molds from the rhizosphere of E. crassipes cultured in NH4Cl solution were two orders of magnitude higher than those from the rhizospheres of plants cultured in distilled water and KNO3 solution. Using a culture-independent method of polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) of 16S rDNA, we found that the form of nitrogen could influence the components of the rhizosphere microbial community. Pseudoxanthomonas, Enterobacter and Citrobacter were present in all of the samples cultured under the three different experimental conditions. The genus Reyranella was found only in samples cultured in KNO3 solution; Acinetobacter and Streptomyces were unique to samples cultured in NH4Cl solution, and Pseudomonas, Pseudacidovorax and Methylosinus were found only in samples cultured in distilled water. Pseudoxanthomonas and Acidovorax were the dominant genera in the rhizosphere microbial community of E. crassipes cultured in KNO3 solution, while Novosphingobium was the dominant genus in the sample cultured in a nitrogen-deficient medium. Our results provide a theoretical foundation for using E. crassipes as a phytoremediation plant and controlling the widespread distribution of E. crassipes around the world using principles of nutrient metabolism.

ResumenComunidades microbianas de la rizósfera son importantes para la fitorremediación, nutrición vegetal, salud y metabolismo. Muchos factores, incluyendo la especie de planta, el pH y los factores nutricionales influyen en la microbiología de la rizósfera. En este estudio, se analizaron los efectos de las diferentes formas del nitrógeno en la estructura de las comunidades microbianas de la rizósfera de E. crassipes. Mediante métodos de cultivo convencional con medios especiales se cultivaron: bacterias, actinobacterias y mohos. Se encontró que el número de bacterias era en gran parte similar a través de las tres condiciones de cultivo, mientras que el número de actinobacterias y mohos de la rizósfera de E. crassipes cultivadas en solución de NH4Cl era dos órdenes de magnitud superior a los de las rizósferas de plantas cultivadas en agua destilada y solución de KNO3. Utilizando un método de cultivo independiente de electroforesis en gel con gradiente de desnaturalización (PCR-DGGE) del ADNr 16S, se encontró que la forma de nitrógeno podría influir en los componentes de la comunidad microbiana de la rizósfera. Pseudoxanthomonas, Enterobacter y Citrobacter estaban presentes en todas las muestras cultivadas en las tres condiciones experimentales. El género Reyranella se encontró sólo en muestras cultivadas en solución de KNO3; Acinetobacter y Streptomyces eran las únicas muestras cultivadas en solución de NH4Cl, y Pseudomonas, Pseudacidovorax y Methylosinus se encontraron sólo en muestras cultivadas en agua destilada. Pseudoxanthomonas y Acidovorax eran los géneros dominantes en la comunidad microbiana de la rizósfera de E. crassipes cultivadas en solución de KNO3, mientras que Novos phingobium fue el género dominante en la muestra cultivada en un medio deficiente de nitrógeno. Nuestros resultados proporcionan una base teórica para el uso de E. crassipes como planta fitorremediadora y para controlar la distribución generalizada de E. crassipes en todo el mundo a través de los principios del metabolismo de nutrientes.

Effects of different forms of nitrogen on rhizosphere microbial community structure of Eichhornia crassipes (Pontederiaceae).

Rhizosphere microbial communities are important for phytoremediation, plant nutrition, health and metabolism. Many factors, including plant species, pH and nutritional factors influence rhizosphere micro- biology. In this study, we analysed the effects of different forms of nitrogen on the structures of rhizosphere microbial communities of E. crassipes. Using a conventional culture method with special media, bacteria, acti- nobacteria and molds were cultured. We found that the numbers of bacteria were largely similar across the three culture conditions, while the numbers of actinobacteria and molds from the rhizosphere of E. crassipes cultured in NH4Cl solution were two orders of magnitude higher than those from the rhizospheres of plants cultured in distilled water and KNO3 solution. Using a culture-independent method of polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) of 16S rDNA, we found that the form of nitrogen could influence the components of the rhizosphere microbial community. Pseudoxanthomonas, Enterobacter and Citrobacter were present in all of the samples cultured under the three different experimental conditions. The genus Reyranella was found only in samples cultured in KNO(3) solution; Acinetobacter and Streptomyces were unique to samples cultured in NH(4)Cl solution, and Pseudomonas, Pseudacidovorax and Methylosinus were found only in samples cultured in distilled water. Pseudoxanthomonas and Acidovorax were the dominant genera in the rhizosphere microbial community of E. crassipes cultured in KNO(3) solution, while Novosphingobium was the dominant genus in the sample cultured in a nitrogen-deficient medium. Our results provide a theoretical foundation for using E. crassipes as a phytoremediation plant and controlling the widespread distribution of E. crassipes around the world using principles of nutrient metabolism.