Bacterial community profile of the crude oil-contaminated saline soil in the Yellow River Delta Natural Reserve, China.

Crude oil contamination greatly influence soil bacterial community. Proliferative microbes in the crude oil-contaminated soil are closely related to the living conditions. Oil wells in the Yellow River Delta Natural Reserve (YRDNR) region is an ideal site for investigating the bacterial community of crude oil-contaminated saline soil. In the present study, 18 soil samples were collected from the depths of 0-20 cm and 20-40 cm around the oil wells in the YRDNR. The bacterial community profile was analyzed through high-throughput sequencing to trace the oil-degrading aerobic and anaerobic bacteria. The results indicated that C15-C28 and C29-C38 were the main fractions of total petroleum hydrocarbon (TPH) in the sampled soil. These TPH fractions had a significant negative effect on bacterial biodiversity (Shannon, Simpson, and Chao1 indices), which led to the proliferation of hydrocarbon-degrading bacteria. A comprehensive analysis between the environmental factors and soil microbial community structure showed that Streptococcus, Bacillus, Sphingomonas, and Arthrobacter were the aerobic hydrocarbon-degrading bacteria; unidentified Rhodobacteraceae and Porticoccus were considered to be the possible facultative anaerobic bacteria with hydrocarbon biodegradation ability; Acidithiobacillus, SAR324 clade, and Nitrosarchaeum were predicted to be the anaerobic hydrocarbon-degrading bacteria in the sub-surface soil. Furthermore, large amount of carbon sources derived from TPH was found to cause depletion of bioavailable nitrogen in the soil. The bacteria associated with nitrogen transformation, such as Solirubrobacter, Candidatus Udaeobacter, Lysinibacillus, Bradyrhizobium, Sphingomonas, Mycobacterium, and Acidithiobacillus, were highly abundant; these bacteria may possess the ability to increase nitrogen availability in the crude oil-contaminated soil. The bacterial community functions were significantly different between the surface and the sub-surface soil, and the dissolved oxygen concentration in soil was considered to be potential influencing factor. Our results could provide useful information for the bioremediation of crude oil-contaminated saline soil.

[Acupuncture preconditioning at "Zusanli"(ST36) and "Zhongwan"(CV12) prevents stress gastric ulcer by regulating the TLR4/MyD88/IκB signaling pathway].

OBJECTIVE: To observe the effect of electroacupuncture preconditioning at "Zusanli"(ST36，Lower Confluent point) and "Zhongwan"(CV12，Front-Mu point) combination on oxidative stress and inflammation-related indicators, Toll-like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88) and inhibitor-α of nuclear transcription factor κB (IκB-α) in serum and gastric tissue of rats with stress gastric ulcer(SGU)，so as to explore its mechanisms underlying prevention of SGU. METHODS: A total of 36 Wistar rats were randomly divided into blank control, model, positive drug and He-Sea-Front-Mu point combination groups (n=9 in each group). A rat model of SGU was established by restraint water-immersion stress method. Ten days before mode-ling, rats in the He-Sea-Front-Mu point combination group received electroacupuncture （2 Hz, 0.6 mA）at ST36 and CV12 for 10 min once every other day for 10 days, and those in the positive drug group was treated by gavage of omeprazole (20 mg/kg) once every other day for 10 days. The morphology of the gastric mucosa was observed by naked eyes and hematoxylin-eosin staining, and the ulcer index (UI) and lesion score were calculated. TBA and colorimetric methods, ELISA and Western blot were used to detect malondialdehyde (MDA), myeloperoxidase (MPO), glutathione peroxidase (GSH-Px), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) levels and the relative expressions of TLR4, MyD88, and IκB-α protein, separately. RESULTS: The gastric mucosa of rats in the blank control group was smooth and intact, the cells were arranged neatly, and there was no telangiec-tasia, hyperemia and inflammatory cell infiltration. The gastric mucosal epithelial structure of rats in the model group was destroyed, and a large number of mucosal epithelial cell death and inflammatory cell infiltration were seen. The degree of gastric mucosal injury and inflammatory cell infiltration in the positive drug group and the combined point group was less than that in the model group. Compared with the blank control group, the UI and lesion score of rats in the model group were significantly increased (P<0.05), the levels of MDA and MPO in the serum and gastric tissues were significantly increased (P<0.05), GSH-Px was significantly reduced (P<0.05), the contents of TNF-α and IL-6 in serum were markedly increased (P<0.05), the expression levels of TLR4 and MyD88 proteins in gastric tissue were significantly increased (P<0.05), IκB-α was significantly reduced (P<0.05). After intervention and in comparison with the model group showed that, the UI and lesion score, the levels of MDA and MPO, contents of serum TNF-α and IL-6, expression levels of TLR4 and MyD88 proteins in positive drug and He-Sea-Front-Mu point combination groups were significantly decreased (P<0.05), while GSH-Px and IκB-α were significantly increased (P<0.05); There were no significant differences in the above indicators between the positive drug and the He-Sea-Front -Mu point combination groups （except TNF-α）. CONCLUSION: Electroacupuncture preconditioning at ST36 and CV12 can prevent SGU, which may be related to its effects in anti-oxidant, anti-inflammatory and regulating TLR4/MyD88/IκB signaling pathway.

Utilization of waste phosphogypsum to prepare hydroxyapatite nanoparticles and its application towards removal of fluoride from aqueous solution.

In the present study, waste phosphogypsum (PG) was utilized firstly to prepare hydroxyapatite nanoparticles (nHAp) via microwave irradiation technology. The nHAp derived from PG exhibited a hexagonal structure with the particle size about 20 nm × 60 nm and high purity. Meanwhile, the adsorption behaviour of fluoride onto the nHAp derived from PG was investigated to evaluate the potential application of this material for the treatment of the wastewater polluted with fluoride. The results indicate that the nHAp derived from PG can be used as an efficient adsorbent for the removal of fluoride from aqueous solution. The maximum adsorption capacities calculated from Langmuir-Freundlich model were 19.742, 26.108, 36.914 and 40.818 mg F(-)/g nHAp for 298, 308, 318 and 328 K, respectively. The pseudo-second order kinetic model was found to provide the best correlation of the used experimental data compared to the pseudo-first order and the adsorption isotherm could be well defined by Langmuir-Freundlich equation. The adsorption mechanism investigation shows that electrostatic interaction and hydrogen bond are the main driving force for fluoride uptake onto nHAp derived from waste PG.