Effect of Biocontrol Agent Pseudomonas fluorescens 2P24 on Soil Fungal Community in Cucumber Rhizosphere Using T-RFLP and DGGE

Fungi and fungal community play important roles in the soil ecosystem, and the diversity of fungal community could act as natural antagonists of various plant pathogens. Biological control is a promising method to protect plants as chemical pesticides may cause environment pollution. Pseudomonas fluorescens 2P24 had strong inhibitory on Rastonia solanacearum, Fusarium oxysporum and Rhizoctonia solani, etc., and was isolated from the wheat rhizosphere take-all decline soils in Shandong province, China. However, its potential effect on soil fungal community was still unknown. In this study, the gfp-labeled P. fluorescens 2P24 was inoculated into cucumber rhizosphere, and the survival of 2P24 was monitored weekly. The amount decreased from 108 to 105 CFU/g dry soils. The effect of 2P24 on soil fungal community in cucumber rhizosphere was investigated using T-RFLP and DGGE. In T-RFLP analysis, principle component analysis showed that the soil fungal community was greatly influenced at first, digested with restriction enzyme Hinf I and Taq I. However, there was little difference as digested by different enzymes. DGGE results demonstrated that the soil fungal community was greatly shocked at the beginning, but it recovered slowly with the decline of P. fluorescens 2P24. Four weeks later, there was little difference between the treatment and control. Generally speaking, the effect of P. fluorescens 2P24 on soil fungal community in cucumber rhizosphere was just transient

The Independent Impacts of PM2.5 Dropping on the Physical and Chemical Properties of Atmosphere over North China Plain in Summer during 2015–2019

Great changes occurred in the physical and chemical properties of the atmosphere in the North China Plain (NCP) in summer caused by PM2.5 dropping from 58 μg/m3 in 2015 to 36.0 μg/m3 in 2019. In this study, we first applied the WRF-Chem model to quantify the impact of PM2.5 reduction on shortwave radiation reaching the ground (SWDOWN), planetary boundary layer height (PBLH), and the surface concentration of air pollutants (represented by CO). Simulation results obtained an increase of 15.0% in daytime SWDOWN and 9.9% in daytime PBLH, and a decrease of −5.0% in daytime CO concentration. These changes were induced by the varied PM2.5 levels. Moreover, the variation in SWDOWN further led to a rise in the NO2 photolysis rate (JNO2) over this region, by 1.82 × 10−4~1.91 × 10−4 s−1 per year. Afterwards, we employed MCM chemical box model to explore how the JNO2 increase and the precursor decrease (CO, VOCs, and NOx) influenced O3 and HOx radicals. The results revealed that the photolysis rate (J) increase would individually cause a change on daytime surface O3, OH, and HO2 radicals by +9.0%, +18.9%, and +23.7%; the corresponding change induced by the precursor decrease was −2.5%, +1.9%, and −2.3%. At the same time, the integrated impacts of the change in J and precursors cause an increase of +6.3%, +21.1%, and +20.9% for daytime surface O3, OH, and HO2. Generally, the atmospheric oxidation capacity significantly enhanced during summer in NCP due to the PM2.5 dropping in recent years. This research can help understand atmosphere changes caused by PM2.5 reduction comprehensively

Prostacyclin analogue beraprost inhibits cardiac fibroblast proliferation depending on prostacyclin receptor activation through a TGF β-Smad signal pathway.

Previous studies showed that prostacyclin inhibited fibrosis. However, both receptors of prostacyclin, prostacyclin receptor (IP) and peroxisome proliferator-activated receptor (PPAR), are abundant in cardiac fibroblasts. Here we investigated which receptor was vital in the anti-fibrosis effect of prostacyclin. In addition, the possible mechanism involved in protective effects of prostacyclin against cardiac fibrosis was also studied. We found that beraprost, a prostacyclin analogue, inhibited angiotensin II (Ang II)-induced neonatal rat cardiac fibroblast proliferation in a concentration-dependent and time-dependent manner. Beraprost also suppressed Ang II-induced collagen I mRNA expression and protein synthesis in cardiac fibroblasts. After IP expression was knocked down by siRNA, Ang II-induced proliferation and collagen I synthesis could no longer be rescued by beraprost. However, treating cells with different specific inhibitors of PPAR subtypes prior to beraprost and Ang II stimulation, all of the above attenuating effects of beraprost were still available. Moreover, beraprost significantly blocked transforming growth factor β (TGF β) expression as well as Smad2 phosphorylation and reduced Smad-DNA binding activity. Beraprost also increased phosphorylation of cAMP response element binding protein (CREB) at Ser133 in the nucleus. Co-immunoprecipitation analysis revealed that beraprost increased CREB but decreased Smad2 binding to CREB-binding protein (CBP) in nucleus. In conclusion, beraprost inhibits cardiac fibroblast proliferation by activating IP and suppressing TGF β-Smad signal pathway

MicroRNA-214-3p protects against myocardial ischemia-reperfusion injury by targeting demethylase lysine demethylase 3A

Objective: Many studies have explored the roles of microRNAs (miRs) in myocardial ischemia/reperfusion injury (MI/RI), while the function of miR-214-3p in MI/RI remained obscure. This study aims to unravel the regulatory mechanism of miR-214-3p in MI/RI via targeting histone demethylase lysine demethylase 3A (KDM3A). Methods: MI/RI rat model was established by ligating the left anterior descending coronary artery. MiR-214-3p and KDM3A expression in myocardial tissues of MI/RI rats was examined. Then, the serum oxidative stress factors, inflammatory factors, pathological changes of myocardial tissues, cardiomyocyte apoptosis, and fibrosis of myocardial tissues were detected in MI/RI rats intervening with miR-214-3p or KDM3A expression. The targeting relation between miR-214-3p and KDM3A was validated. Results: MiR-214-3p was low-expressed while KDM3A was high-expressed in MI/RI rat model. Up-regulated miR-214-3p or down-regulated KDM3A protected against MI/RI via mitigating serum oxidative response, reducing the levels of inflammatory factors, alleviating the pathological changes of myocardial tissues, and decreasing cardiomyocyte apoptosis and fibrosis of myocardial tissue. KDM3A amplification reversed the therapeutic effects of elevated miR-214-3p on MI/RI. KDM3A was targeted by miR-214-3p. Conclusion: miR-214-3p hinders cardiomyocyte apoptosis and myocardial injury in MI/RI rats via regulating KDM3A. Thus, miR-214-3p may function as a potential candidate for MI/RI treatment

Ruminal fermentation and microbial community differently influenced by four typical subtropical forages in vitro

The present study evaluated the effects of 4 typical subtropical forages on ruminal microbial community composition to formulate a better diet for buffalo. Corn straw silage, elephant grass, cassava residues and sugarcane tail silage were used as substrates for in vitro fermentation. Eight replicates were set up for every substrate, and fermentation was carried out in a 100-mL glass syringe, using buffalo rumen inoculum. Every replicate was anaerobically dispensed with 10 mL of rumen inoculum, 20 mL of McDougall's buffer and 200 mg of dried substrate, and placed in a water bath at 39 °C. Gas production was recorded at 0, 2, 6, 12, 24, 36, 48 and 72 h of incubation. After 24 h, fermentation was ceased for 4 replicates and samples were collected. Volatile fatty acids (VFA) concentrations were measured using gas chromatography. Microbial populations were quantified using quantitative real-time PCR (qRT-PCR), and microbial community was analyzed using high throughput sequencing technology. The results showed, cassava residues as substrate had the highest gas production, acetate, propionate and total VFA concentrations (P < 0.05), and corn straw silage had the lowest acetate:propionate ratio (P < 0.05). The lowest numbers of fungi, Ruminococcus albus and Fibrobacter succinogenes, and the highest number of protozoa were observed with cassava residues (P < 0.05). The least abundances of bacterial phyla Firmicutes, Bacteroidetes and genus Prevotella, and substantially higher abundance of phylum proteobacteria (56%) and genus Succinivibrio (52%) were observed with cassava residues. The most abundances of Methanobrevibacter gottschalkii and Entodinium were observed with cassava residues. Spearman's correlations analysis showed, Succinivibrio had strong positive correlations with propionate, butyrate, Metadinium and M. gottschalkii, indicating fermentation products were related to microbial community. In conclusion, incubation with cassava residues resulted in lower number of fiber degrading microbes but higher protozoal population because of its low fiber contents. The microbial community was highly altered by in vitro incubation with cassava residues, whereas remained similar for the other 3 high fiber containing substrates. Keywords: Buffalo rumen inoculum, In vitro fermentation, Subtropical forages, Microbial population, Microbial communit

Proximity matrix of T-RFLP profiles of soil samples (<i>Hinf</i> I).

<p>“C” was on behalf of the controls amended with water, and “P” was on behalf of the treatments amended with <i>P. fluorescens</i> 2P24. The number (7, 14, 21, 28, 35, 42, 49, 56, 63) following the abbreviation letters “C” and “P” represented the sampling day after inoculation.</p

Principal component analysis (PCA) of T-RFLP profiles of soil samples (<i>Hinf</i> I).

<p>Symbols referred to individual replicates of different treatments. “C” was on behalf of the controls amended with water, and “P” was on behalf of the treatments amended with <i>P. fluorescens</i> 2P24. The number (7, 14, 21, 28, 35, 42, 49, 56, 63) following the abbreviation letters “C” and “P” represented the sampling day after inoculation. Numbers in parenthesis were percentage variance explained by each principal component (PC).</p