Imaging the short-lived hydroxyl-hydronium pair in ionized liquid water

[Figure: see text].

Bioleaching of tellurium from mine tailings by indigenous Acidithiobacillus ferrooxidans

Tellurium (Te) is a scarce and valuable metalloid, which can be found in some mine tailings. In this work, an indigenous Acidithiobacillus ferrooxidans strain was used to leach Te from mine tailings collected in the Shimian Te mine region, China. Under the optimized conditions of initial pH of 2·0, pulp density of 4% and temperature of 30°C, 47·77% of Te can be dissolved after 24 days of bioleaching. The leaching of Te by different systems such as bioleaching, Ferric ion (Fe(III)) leaching and acid leaching was compared. The results showed that the leaching behaviour of Te is similar to that of sulphur in sulphide minerals, that is, Fe(III) first oxidizes telluride (Te(-II)) in minerals to elemental Te, and then elemental Te can be oxidized by bacteria to Te(IV) and Te(VI). Besides, it was also showed by scanning electron microscope observation and Fourier transform infrared spectroscopy analysis of the ore sample before and after bioleaching that some bedded structure covered on the surface of the ore after bioleaching acting as a reaction compartment, and the changing of active groups indicated a possible attachment between bacteria and ore. There is an indirect mechanism involved in bioleaching of Te.

MDA5 attenuate autophagy in chicken embryo fibroblasts infected with IBDV

1. The role of melanoma differentiation-associated protein 5 (MDA5) in infectious bursal disease virus (IBDV)-induced autophagy was studied in chicken embryos.2. Chicken embryo fibroblasts (CEF) were used as the research model and small interfering RNA (siRNA), western blot, indirect enzyme-linked immunosorbent assay (ELISA), real-time fluorescence quantitative polymerase chain reaction (PCR) and transmission electron microscopy were used to detect autophagy, IBDV replication, CEF damage, and activation of both MDA5 and its signalling pathway.3. The results showed that CEF infected with IBDV activated the intracellular MDA5 signalling pathway and caused autophagy via inactivation of the AKT/mTOR pathway. While autophagy promotes IBDV proliferation, MDA5 weakens IBDV-induced CEF autophagy thus inhibiting IBDV replication and protecting CEF cells.4. The results indicated that chMDA5 can be activated by IBDV and attenuate CEF autophagy caused by IBDV infection, thereby inhibiting IBDV replication. This study provided a foundation for further exploring the relationship between viruses, autophagy and the pathogenic mechanism of the MDA5 pathway involved in IBDV.

High urinary excretion rate of glucose attenuates serum uric acid level in type 2 diabetes with normal renal function

AIMS/INTRODUCTION

The relationship between urinary excretion rate of glucose (UEGL) and uric acid (UA) metabolism in adults with type 2 diabetes (T2D) remains unclear to date. This study aimed to investigate the relationships of UEGL with serum UA (SUA), urinary excretion rate of uric acid (UEUA), and renal clearance of uric acid (CLUA) in adults with T2D. We hypothesised that high UEGL increases UA excretion, which in turn leads to lower SUA.

MATERIALS AND METHODS

This was a cross-sectional study of 635 inpatients with T2D recruited between 2018 and 2019. The relationships of UEGL with UEUA, CLUA, and hyperuricaemia were assessed using analysis of covariance and multivariate regression analysis.

RESULTS

Patients in the higher quartile of UEGL tended to have lower SUA levels than those in the lower quartile. In contrast, patients in the higher quartile of UEGL tended to have higher CLUA (p for trend < 0.0001), and a similar trend was observed for UEUA. In adjusted multivariable linear regression model, UEGL was negatively correlated with SUA (β = - 0.023, 95% CI - 0.034 to - 0.013, p < 0.0001). However, positive correlations of UEGL with UEUA (β = 0.046, 95% CI 0.018-0.074, p = 0.001) and CLUA (β = 0.063, 95% CI 0.042-0.085, p < 0.0001) were found. Furthermore, consistent significant inverse associations were observed between quartiles of UEGL and hyperuricaemia in the adjusted multivariate logistic regression model.

CONCLUSIONS

A high UEGL level was positively correlated with UEUA and CLUA. Moreover, it was inversely associated with SUA level, and a consistently increased UEGL level reduced the risk of hyperuricaemia in patients with T2D.

Aerobactin-Mediated Iron Acquisition Enhances Biofilm Formation, Oxidative Stress Resistance, and Virulence of Yersinia pseudotuberculosis

Aerobactin is a citrate-hydroxamate siderophore that is critical for the virulence of pathogenic enteric bacteria. However, although the aerobactin-producing iucABCD-iutA operon is distributed widely in the genomes of Yersinia species, none of the pathogenic Yersinia spp. was found to produce aerobactin. Here, we showed that the iucABCD-iutA operon in the food-borne enteric pathogen Yersinia pseudotuberculosis YPIII is a functional siderophore system involved in iron acquisition. The expression of the operon was found to be directly repressed by the ferric uptake regulator (Fur) in an iron concentration-dependent manner. In addition, we demonstrated that the aerobactin-mediated iron acquisition contributes to bacterial growth under iron-limited conditions. Moreover, we provided evidence that aerobactin plays important roles in biofilm formation, resistance to oxidative stress, ROS removal, and virulence of Y. pseudotuberculosis. Overall, our study not only uncovered a novel strategy of iron acquisition in Y. pseudotuberculosis but also highlighted the importance of aerobactin in the pathogenesis of Y. pseudotuberculosis.

Dysbiosis of intestinal microbiota in early life aggravates high-fat diet induced dysmetabolism in adult mice

BACKGROUND

Accumulating evidence have shown that the intestinal microbiota plays an important role in prevention of host obesity and metabolism disorders. Recent studies also demonstrate that early life is the key time for the colonization of intestinal microbes in host. However, there are few studies focusing on possible association between intestinal microbiota in the early life and metabolism in adulthood. Therefore the present study was conducted to examine whether the short term antibiotic and/or probiotic exposure in early life could affect intestinal microbes and their possible long term effects on host metabolism.

RESULTS

A high-fat diet resulted in glucose and lipid metabolism disorders with higher levels of visceral fat rate, insulin-resistance indices, and leptin. Exposure to ceftriaxone in early life aggravated the negative influences of a high-fat diet on mouse physiology. Orally fed TMC3115 protected mice, especially those who had received treatment throughout the whole study, from damage due to a high-fat diet, such as increases in levels of fasting blood glucose and serum levels of insulin, leptin, and IR indices. Exposure to ceftriaxone during the first 2 weeks of life was linked to dysbiosis of the fecal microbiota with a significant decrease in the species richness and diversity. However, the influence of orally fed ceftriaxone on the fecal microbiota was limited to 12 weeks after the termination of treatment. Of note, at week 12 there were still some differences in the composition of intestinal microbiota between mice provided with high fat diet and antibiotic exposure and those only fed a high fat diet.

CONCLUSIONS

These results indicated that exposure to antibiotics, such as ceftriaxone, in early life may aggravate the negative influences of a high-fat diet on the physiology of the host animal. These results also suggest that the crosstalk between the host and their intestinal microbiota in early life may be more important than that in adulthood, even though the same intestinal microbes are present in adulthood.

Gas kinetic flux solver based high-order finite-volume method for simulation of two-dimensional compressible flows

In this work, a high-order gas kinetic flux solver (GKFS) is developed for simulation of two-dimensional (2D) compressible flows. Different from the conventional gas kinetic scheme, which uses the local integral solution to the Boltzmann equation to reconstruct the numerical fluxes of macroscopic governing equations, the GKFS evaluates the numerical fluxes by the local asymptotic solution to the Boltzmann equation. This local asymptotic solution consists of the equilibrium distribution function and its substantial derivative at the cell interface. To achieve high-order accuracy in the simulation, the substantial derivative is discretized by a difference scheme with second-order accuracy in time and fourth-order accuracy in space, which results in a polynomial of the equilibrium distribution function at different locations and time levels. The Taylor series expansion is then introduced to simplify this polynomial. As a result, a simple high-order accurate local asymptotic solution to the Boltzmann equation is obtained and the numerical fluxes of macroscopic governing equations are given explicitly. A series of numerical examples are presented to validate the accuracy and capability of the developed high-order GKFS. Numerical results demonstrate that the high-order GKFS can achieve the desired accuracy on both the quadrilateral mesh and the triangular mesh and it outperforms the second-order counterpart.

[Analysis of maternal mortality trend and age-period-cohort model in China from 1992 to 2017]

Objective: To understand the trend of maternal mortality in China from 1992 to 2017, and to evaluate the effects of age, period and cohort of maternal mortality by using the age-period-cohort (APC) model. Methods: The data of maternal mortality in China from 1992 to 2017 were collected from the Global Burden of Disease project. The maternal mortality rate was adopted to describe the trend of death. The APC model and the estimable function algorithm were used to evaluate the impact of age, period and birth cohort factors on maternal mortality risk in China. Results: From1992 to 2017, the maternal mortality rate in China fluctuated slightly and then continued to decline and finally increased slightly. During this period, the net drift was -10.00% per year (95%CI:-10.92% to -9.08% per year), and all the local drifts were lower than zero in all age groups of 10-54 years old (P<0.05). The results of the APC model analysis showed that the maternal mortality risk of women in their life stage showed a trend of rapid decrease, then a slow climb and finally a rapid increase. The period relative risk and cohort relative risk of maternal mortality both showed a monotonous decreasing trend. Conclusion: From 1992 to 2017, the maternal mortality rate in China generally shows a downward trend, and the risk of maternal mortality has significant age, period and cohort effects.

The transcriptional regulator Zur regulates the expression of ZnuABC and T6SS4 in response to stresses in Yersinia pseudotuberculosis

Zinc homeostasis is crucial for the development and stress resistance of bacteria in the environment. Serial zinc sensing transcriptional regulators, zinc transporters and zinc binding proteins were found to maintain the zinc homeostasis in bacteria. Zur is a zinc uptake regulator that is widely distributed in species, and ZnuABC, as well as the Type VI Secretion System (T6SS4) function in zinc acquisition. Here, we report that the regulator Zur inhibits the expression of the ZnuABC which inhibition could be eliminated at low zinc level, and upregulates the T6SS4 operon in Yersinia pseudotuberculosis to facilitate Zn²⁺ uptake and oxidative stress resistance. Zur regulates the expression of ZnuABC and T6SS4 by directly binding to their promoter regions. Zur senses the Zn²⁺ concentration and represses ZnuABC in a Zn²⁺-containing environment. Zur works as an auxiliary regular activator of T6SS4, facilitating oxidative stress resistance. This study revealed the dual function of regulator Zur on ZnuABC and T6SS4, and enriched the knowledge of Zn²⁺ homeostasis maintenance in Y. pseudotuberculosis.

Transcriptomic investigation of embryonic pectoral muscle reveals increased myogenic processes in Shitou geese compared to Wuzong geese

1.Embryonic stages before birth are crucial for poultry muscle development, as this determines muscle mass in adulthood. This study characterised the distinction in embryonic pectoral muscle development between Wuzong (WZE, small) and Shitou (STE, large) geese (two indigenous goose breeds in Guangdong Province, China) at embryonic days 15 (E15), 23 (E23) and the day of hatching (P1) to gain insights into the regulatory mechanisms of muscle development.2.The results showed that STE had significantly higher myofibre density during E15-P1 and had significantly larger myofibre diameter at E15 than WZE. By RNA-sequencing analysis, 19 507 genes were detected, and 7121 differentially expressed genes (DEGs) were identified.3.Gene expression distinctions between breeds began increasing from E23, and WZE had different gene expression profiles compared to STE. A GO analysis of DEGs indicated that myo-genes involved at E15 may influence distinct pectoral muscle development characteristics between WZE and STE. The RT-qPCR results were consistent with the RNA-sequencing analysis. Four muscle structure protein coding genes (MYL2, MYL3, TNNI2 and TNNC2 and three other functional genes (CAV3, CACNA1S and NOS1) were identified in a predicted interaction network. These functional genes may interact with muscle structural protein coding genes to regulate embryonic pectoral muscle development in WZE and STE geese.4.The study revealed that STE and WZE had divergent embryonic pectoral muscle development patterns and these differences may begin before E15.

Quantitative agreement between dynamical rocking curves in ultrafast electron diffraction for x-ray lasers

Electron diffraction through a thin patterned silicon membrane can be used to create complex spatial modulations in electron distributions. By precisely varying parameters such as crystallographic orientation and wafer thickness, the intensity of reflections in the diffraction plane can be controlled and by placing an aperture to block all but one spot, we can form an image with different parts of the patterned membrane, as is done for bright-field imaging in microscopy. The patterned electron beams can then be used to control phase and amplitude of subsequent x-ray emission, enabling novel coherent x-ray methods. The electrons themselves can also be used for femtosecond time resolved diffraction and microscopy. As a first step toward patterned beams, we demonstrate experimentally and through simulation the ability to accurately predict and control diffraction spot intensities. We simulate MeV transmission electron diffraction patterns using the multislice method for various crystallographic orientations of a single crystal Si(001) membrane near beam normal. The resulting intensity maps of the Bragg reflections are compared to experimental results obtained at the Accelerator Structure Test Area Ultrafast Electron Diffraction (ASTA UED) facility at SLAC. Furthermore, the fraction of inelastic and elastic scattering of the initial charge is estimated along with the absorption of the membrane to determine the contrast that would be seen in a patterned version of the Si(001) membrane.

Contact-independent killing mediated by a T6SS effector with intrinsic cell-entry properties

Bacterial type VI secretion systems (T6SSs) inject toxic effectors into adjacent eukaryotic and prokaryotic cells. It is generally thought that this process requires physical contact between the two cells. Here, we provide evidence of contact-independent killing by a T6SS-secreted effector. We show that the pathogen Yersinia pseudotuberculosis uses a T6SS (T6SS-3) to secrete a nuclease effector that kills other bacteria in vitro and facilitates gut colonization in mice. The effector (Tce1) is a small protein that acts as a Ca²⁺- and Mg²⁺-dependent DNase, and its toxicity is inhibited by a cognate immunity protein, Tci1. As expected, T6SS-3 mediates canonical, contact-dependent killing by directly injecting Tce1 into adjacent cells. In addition, T6SS-3 also mediates killing of neighboring cells in the absence of cell-to-cell contact, by secreting Tce1 into the extracellular milieu. Efficient contact-independent entry of Tce1 into target cells requires proteins OmpF and BtuB in the outer membrane of target cells. The discovery of a contact-independent, long-range T6SS toxin delivery provides a new perspective for understanding the physiological roles of T6SS in competition. However, the mechanisms mediating contact-independent uptake of Tce1 by target cells remain unclear.

Bacteria can use type VI secretion systems (T6SSs) to inject toxic effector proteins into adjacent cells, in a contact-dependent manner. Here, the authors provide evidence of contact-independent killing by a T6SS effector that is secreted into the extracellular milieu and then taken up by other bacterial cells.

Identification of Robinia pseudoacacia target proteins responsive to Mesorhizobium amphore CCNWGS0123 effector protein NopT

Nodulation outer proteins secreted via type 3 secretion systems are involved in the process of symbiosis between legume plants and rhizobia. To study the function of NopT in symbiosis, we mutated nopT in Mesorhizobium amphore CCNWGS0123 (GS0123), which can nodulate black locust (Robinia pseudoacacia). The nopT mutant induced higher levels of jasmonic acid, salicylic acid, and hydrogen peroxide accumulation in the roots of R. pseudoacacia compared with wild-type GS0123. The ΔnopT mutant induced higher disease-resistant gene expression 72 hours post-inoculation (hpi), whereas GS0123 induced higher disease-resistant gene expression earlier, at 36 hpi. Compared with the nopT mutant, GS0123 induced the up-regulation of most genes at 36 hpi and the down-regulation of most genes at 72 hpi. Proteolytically active NopT_GS0123 induced hypersensitive responses when expressed transiently in tobacco leaves (Nicotiana benthamiana). Two NopT_GS0123 targets in R. pseudoacacia were identified, ATP-citrate synthase alpha chain protein 2 and hypersensitive-induced response protein. Their interactions with NopT_GS0123 triggered resistance by the plant immune system. In conclusion, NopT_GS0123 inhibited the host plant immune system and had minimal effect on nodulation in R. pseudoacacia. Our results reveal the underlying molecular mechanism of NopT function in plant-symbiont interactions.

Alterations in immune and antioxidant gene networks by gamma-d-glutamyl-meso-diaminopimelic acid in bovine mammary epithelial cells are attenuated by in vitro supply of methionine and arginine

Nucleotide-binding oligomerization domain (NOD)-like receptor 1 (NOD1) is a cytosolic pattern recognition receptor with a crucial role in the innate immune response of cells triggered by the presence of compounds such as gamma-d-glutamyl-meso-diaminopimelic acid (iE-DAP) present in the peptidoglycan of all gram-negative and certain gram-positive bacteria. Methionine (Met) and arginine (Arg) are functional AA with immunomodulatory properties. In the present study, we aimed to assess the effect of increased Met and Arg supply on mRNA abundance of genes associated with innate immune response, antioxidant function, and AA metabolism during iE-DAP challenge in bovine mammary epithelial cells (BMEC). Primary BMEC (n = 4 per treatment) were precultured in modified medium for 12 h with the following AA formulations: ideal profile of AA (control), increased Met supply (incMet), increased Arg supply (incArg), or increased supply of Met plus Arg (incMetArg). Subsequently, cells were challenged with or without iE-DAP (10 μg/mL) for 6 h. Data were analyzed as a 2 × 2 × 2 factorial using the MIXED procedure of SAS 9.4. Greater mRNA abundance of NOD1, the antioxidant enzyme SOD1, and AA transporters (SLC7A1 and SLC3A2) was observed in the incMet cells after iE-DAP stimulation. Although increased Met alone had no effect, incMetArg led to greater abundance of the inflammatory cytokine IL-6, and the antioxidant enzyme GPX1 after iE-DAP stimulation. The increased Arg alone downregulated NOD1 after iE-DAP stimulation, coupled with a downregulation in the AA transporters mRNA abundance (SLC7A1, SLC7A5, SLC3A2, and SLC38A9), and upregulation in GSS and KEAP1 mRNA abundance. Overall, the data indicated that increased supply of both Met and Arg in the culture medium were more effective in modulating the innate immune response and antioxidant capacity of BMEC during in vitro iE-DAP stimulation.