Effect of straw retention and mineral fertilization on P speciation and P-transformation microorganisms in water extractable colloids of a Vertisol

Water extractable colloids (WECs) serve as crucial micro particulate components in soils, playing a vital role in the cycling and potential bioavailability of soil phosphorus (P). Yet, the underlying information regarding soil P species and P-transformation microorganisms at the microparticle scale under long-term straw retention and mineral fertilization is barely known. Here, a fixed field experiment (~13 years) in a Vertisol was performed to explore the impacts of straw retention and mineral fertilization on inorganic P, organic P and P-transformation microorganisms in bulk soils and WECs by sequential extraction procedure, P K-edge X-ray absorptions near-edge structure (XANES), 31P nuclear magnetic resonance (NMR), and metagenomics analysis. In bulk soil, mineral fertilization led to increases in the levels of total P, available P, acid phosphatase (ACP), high-activity inorganic P fractions (Ca2-P, Ca8-P, Al-P, and Fe-P) and organic P (orthophosphate monoesters and orthophosphate diesters), but significantly decreased the abundances of P cycling genes including P mineralization, P-starvation response regulation, P-uptake and transport by decreasing soil pH and increasing P in bulk soil. Straw retention had no significant effects on P species and P-transformation microorganisms in bulk soils but brought increases for organic carbon, total P, available P concentrations in WECs. Furthermore, straw retention caused greater change in P cycling genes between WECs and bulk soils compared with the effect of mineral fertilization. The abundances of phoD gene and phoD-harbouring Proteobacteria in WECs increased significantly under straw retention, suggesting that the P mineralizing capacity increased. Thus, straw retention could potentially accelerate the turnover, mobility and availability of P by increasing the nutrient contents and P mineralizing capacity in microscopic colloidal scale

Mutational Analysis of Highly Conserved Residues in the Phage PhiC31 Integrase Reveals Key Amino Acids Necessary for the DNA Recombination

Background: Amino acid sequence alignment of phage phiC31 integrase with the serine recombinases family revealed highly conserved regions outside the catalytic domain. Until now, no system mutational or biochemical studies have been carried out to assess the roles of these conserved residues in the recombinaton of phiC31 integrase. Methodology/Principal Findings: To determine the functional roles of these conserved residues, a series of conserved residues were targeted by site-directed mutagenesis. Out of the 17 mutants, 11 mutants showed impaired or no recombination ability, as analyzed by recombination assay both in vivo and in vitro. Results of DNA binding activity assays showed that mutants (R18A, I141A, L143A,E153A, I432A and V571A) exhibited a great decrease in DNA binding affinity, and mutants (G182A/F183A, C374A, C376A/G377A, Y393A and V566A) had completely lost their ability to bind to the specific target DNA attB as compared with wild-type protein. Further analysis of mutants (R18A, I141A, L143A and E153A) synapse and cleavage showed that these mutants were blocked in recombination at the stage of strand cleavage. Conclusions/Significance: This data reveals that some of the highly conserved residues both in the N-terminus and C-terminus region of phiC31 integrase, play vital roles in the substrate binding and cleavage. The cysteine-rich motif and th

Multidrug Resistant Brain Abscess Due to Acinetobacter baumannii Ventriculitis Cleared by Intraventricular and Intravenous Tigecycline Therapy: A Case Report and Review of Literature

Objective: Ventricular infection from multidrug-resistant (MDR) Acinetobacter baumannii (A. baumannii) is one of the most severe complications of craniotomy. However, the availability of effective therapeutic options for these infections is limited. Thus, this report aims to describe the efficacy of abscess clearance by intraventricular and intravenous tigecycline therapy in managing patients with multidrug-resistant A. baumannii ventriculitis after neurosurgery. Moreover, the current literature on the use of tigecycline therapy for these life-threatening infections is reviewed and summarized, and a treatment regimen based on the available data is proposed.Methods: A patient with multidrug-resistant A. baumannii ventriculitis was admitted in our hospital and was provided with a detailed therapeutic schedule. Tigecycline treatments for multidrug-resistant A. baumannii ventriculitis that were reported in the literature were also reviewed and summarized.Results: The patient in our hospital underwent abscess clearance on a ventriculoscope and was subsequently subjected to multi-route tigecycline therapy 14 days after the start of the continuous ventricular irrigation (CVI) tigecycline and 3 days after the intraventricular (IVT) tigecycline. The signs of ventriculitis disappeared, and the Acinetobacter cerebrospinal fluid (CSF) load steadily decreased until CSF sterilization. Literature review identified seven cases of ventricular infection from multidrug-resistant A. baumannii treated with tigecycline. In the eight cases, all patients were male adults (>18 years), with a mean age of 46.1 (range: 22–75) years. Meningitis/ventriculitis was secondary to neurosurgery procedures for the management of various central nervous system diseases in all cases. A good clinical outcome was achieved in all eight patients with multidrug-resistant A. baumannii meningitis/ventriculitis treated with CVI and/or IVT tigecycline, and any relevant complications were not observed.Conclusions: CVI and IVT tigecycline and IVT colistin could be considered as the first-line therapy in patients with ventricular infections from MDR/extreme drug-resistant A. baumannii. However, more studies should be conducted to confirm our observation

Self-tuning fusion Wiener filter for multisensor multi-channel AR signals with common disturbance noise

AbstractFor the multisensor multi-channel autoregressive (AR) signals with common disturbance noise, when model parameters and noise variances are unknown, the estimates of model parameters and noise variances can be obtained based on the multi-dimension recursive extended least squares (RELS) algorithm and the correlation method. Further, a self-tuning fusion Wiener filter is presented based on the modern time series analysis method by substituting the estimates for the true values. A simulation example shows the consistence of the estimates of the model parameters and noise variances, and the tracking characteristics of the self-tuning fusion Wiener filter

Transcriptome Analysis of the Toxic Effects of Amisulbrom and Isoflucypram on Zebrafish (<i>Danio rerio</i>) Larvae

Fungicides are frequently detected in the water bodies, however, the adverse effects of these fungicides on aquatic lives remain limited. To better understand the adverse effects of amisulbrom (AML) and isoflucypram (ISO) on embryogenesis, zebrafish embryos were exposed to two different fungicides, 0.75 μM amisulbrom (AML) and 2.5 μM isoflucypram (ISO), for 72 h. Transcriptome sequencing was employed to identify differentially expressed genes (DEGs) after AML and ISO exposure. A total of 571 and 3471 DEGs were detected between the libraries of the two fungicides-treated groups and the control, respectively. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that PPAR signaling pathway, phototransduction, ribosome and p53 signaling pathway were significantly enriched in response to both AML and ISO stress. Moreover, a number of DEGs involved in tyrosine metabolism, phagosome pathway, cell cycle pathway, extracellular matrix (ECM) receptor interaction pathway, and arginine and proline metabolism were specially enriched after exposure to AML; a number of DEGs involved in notch signaling pathway, drug metabolism, alanine, aspartate and glutamate metabolism, amino-acyl−tRNA biosynthesis, and protein processing in endoplasmic reticulum were significantly enriched after exposure to ISO. These results provide novel insights into the toxicological mechanisms underlying fish’s responses to fungicides

Mechanical and Tribological Behaviors of U75VG Rail Flash&minus;Butt Welded Joint

Flash&minus;butt welded rail is widely used in railway transportation; however, the welded joint is vulnerable after a long time of service, and its damage mechanism is controversial. Here, tensile and reciprocating friction tests were carried out to analyze the mechanical and tribological behaviors between the welded joint and the base metal of a U75VG rail. The results show that flash&minus;butt welding promotes the pearlite to transform into ferrite, leading to a relatively low hardness value but high plasticity. In addition, the yielding and strength of the all&minus;weld&minus;metal specimen are 385 MPa and 1090 MPa, respectively, which are about 24.51% and 7.63% lower than that of the base metal specimen. It is worth noting that the elongation of the all&minus;weld&minus;metal specimen is 57.1% higher than that of the base metal specimen, and more dimples and tearing ridges can be detected on the fracture morphology of the all&minus;weld&minus;metal specimen, while the fracture morphology of the base metal specimen is filled with shallow dimples and cleavage planes. Moreover, the weld metal has a relatively higher COF (coefficient of friction), and its fluctuation amplitude is 1.25 times higher than that of the base metal, which is due to the rougher worn surface. Furthermore, the introduction of flash&minus;butt welding changes the wear mechanism of the U75VG rail from adhesive wear and oxidation to fatigue wear and slight oxidation, and ultimately leads to more serious damage

Problems in the Biogas Construction in Weihui City and Development Strategies

Taking the demonstration biogas construction city in Henan Province — Weihui City as the survey and research city, we give an overview of the industrial and agricultural base and current situation of biogas development in Weihui City, and analyze the main problems in biogas construction, such as simple development mode of biogas adopted by rural households, laggard construction of large and medium-sized biogas projects, unsound service system for biogas development and failure to comprehensively use biogas resources. According to the practical work experience, we sum up the followin