Seasonal nitrogen uptake strategies in a temperate desert ecosystem depends on N form and plant species

Symbiotic plants might be able to regulate a limited nitrogen (N) pool, thus avoiding and reducing competition for resources, through the uptake of different chemical N forms. Our aim was to see whether coexisting herbs showed preference for different forms of N in a temperate desert. We conducted a situ experiment using the ¹⁵ N labeling method in the Gurbantunggut Desert of Northwestern China dominated by Erodium oxyrrhynchum, Hyalea pulchella, Nonea caspica and Lactuca undulata during their growing period (April and May). Four desert herb species preferentially relied on ¹⁵ N-NO₃ for their N nutrition. Multi-factor analysis of variance (ANOVA) analysis results showed that species, N forms, months, and soil depths strongly affected N uptake rate. The uptake rate by herbs was higher in May than in April, and higher at 0-5 cm than at 5-15 cm soil layers. Erodium oxyrrhynchum, N. caspica and L. undulata showed different preference on N form over months. Erodium oxyrrhynchum and L. undulata changed their uptake preference from more ¹⁵ N-Glycine in April to more ¹⁵ N-NH4 in May. Although the N uptake rate of four desert herbs varied across different soil depths and months, all species absorbed more inorganic N compared with organic N. The higher preference for ¹⁵ N-NO₃ and ¹⁵ N-NH4 over ¹⁵ N-Gly possibly reflects adaptation to different N forms in temperate desert.

Evaluation of a Collagen-Reactive Monomer with Advanced Bonding Durability

This study evaluated the use of a new collagen-reactive monomer (CRM), isocyanate-terminated urethane methacrylate precursor, which has covalent affinity to dental collagen, in the formation of dentin-resin bonds and compared it with 2 other dental adhesives. Dentin specimens were bonded with either the CRM-based adhesive (CBA), One-Step (OS; Bisco, Inc.), or a negative adhesive (NA) control and subjected to 24-h storage in water, thermocycling to simulate 1-y clinical function, or a matrix metalloproteinase-mediated aging process. We tested the microtensile bond strength (µTBS), characterized the bonding interface with an atomic force microscope, conducted micro-Raman analysis, and performed leakage tests and in situ zymography. CBA and OS exhibited comparable bonding strength after 24 h (P > 0.05); however, there was a sharp decrease in µTBS after aging for all except CBA (P < 0.001). Raman spectra results indicated increased collagen crosslinking and chemical reaction between the adhesive and collagen in the CBA group. CBA achieved high-quality hybridization with collagen, improving mechanical properties and integrity, and decreased the enzyme-mediated degradation of the bonding interface by inhibiting collagenolytic activity. With the promising bonding durability of coapplied CBA, CRM may be the first dental adhesive to provide strong and long-lasting resin-dental collagen bonding without the additional conditioning step. The use of CBA results in high-quality hybrid layers that protect the resin-dentin interface from harmful biological and chemical activities commonly occurring in the oral environment.

Fate and removal of antimony in response to stringent control activities after a mine tailing spill

When tailing spill accidents occur, the risk of contamination by antimony (Sb) tailings into adjacent rivers, sediments, aquifers and soil environments is high. The Sb concentrations in water and sediment under different stringent control activities were investigated for 60 days in the Jialing River basin after a tailing spill accident. Both reservoir regulation and the construction of a temporary dam with coagulation dosing remarkably reduced the Sb levels in the river water. The increase in dissolved Sb caused by the spill was reduced from ~400 μg/L in the inflow to ~200 μg/L in the outflow by reservoir regulation. Moreover, reservoir regulation led to a high concentration of Sb in the reservoir sediment, which was difficult to remove and may cause subsequent unpredictable long-term ecological and health risks. In contrast, the Sb-enriched deposition inside the temporary dam was convenient to remove. Notably, temperature alternations between day and night in winter resulted in a large fluctuation in coagulation efficiency, which may cause the failure of stringent control projects. The results of this study suggest potential improvements to stringent control activities after mine tailing accidents to mitigate environmental impacts and prevent secondary risks.

Analysis on expression level and diagnostic value of miR-19 and miR-21 in peripheral blood of patients with undifferentiated lung cancer

OBJECTIVE

This paper aims to investigate the expression level and diagnostic value of miR-19 miR-21 in peripheral blood of patients with undifferentiated lung cancer.

PATIENTS AND METHODS

58 patients with undifferentiated lung cancer hospitalized in the oncology department of The First Affiliated Hospital of Nanchang University from September 2014 to May 2017 were selected as the experimental group, and 42 healthy volunteers in the same period as the control group at the same time. General clinical data in the two groups were collected. The expression levels of miR-19 and miR-21 in peripheral blood of the two groups were measured by Real-Time fluorescence quantitative Polymerase Chain Reaction. The expression levels of peripheral blood miR-19 and miR-21 in large and small cell lung cancer of undifferentiated lung cancer were analyzed and compared. ROC curve was used to analyze the diagnostic value of miR-19 and miR-21 in undifferentiated lung cancer.

RESULTS

The expression levels of miR-19 and miR-21 in peripheral blood of the experimental group were significantly higher than those of the control group (p<0.05). The AUC of miR-19 in the diagnosis of undifferentiated lung cancer was 0.854; the sensitivity was 98.30%; the specificity was 54.29% and the cut off was 3.54. The AUC of miR-21 in the diagnosis of undifferentiated lung cancer was 0.923; the sensitivity was 86.20%; the specificity was 76.19% and the cut off was 3.89. The AUC of combined detection in the diagnosis of undifferentiated lung cancer was 0.952; the sensitivity was 86.60%; the specificity was 97.62% and the cut off was 0.68. The specificity of combined detection was higher than that of miR-19 and miR-21 (p<0.05).

CONCLUSIONS

MiR-19 and miR-21 are highly expressed in peripheral blood of patients with undifferentiated lung cancer; miR-19 and miR-21 are expected to be used as diagnostic markers for undifferentiated lung cancer.

Ionization-induced adiabatic soliton compression in gas-filled hollow-core photonic crystal fibers

We investigate in the experiments the ionization-induced adiabatic soliton compression process in a short length of He-filled single-ring photonic crystal fiber. We observe that the plasma-driven blueshifting solitons show little residual light near the pump wavelength in a certain pulse energy region, leading to a high-efficiency frequency upconversion process. In contrast, at high pulse energy levels, we observe that the quality of the frequency upshifting process is impaired due to the existence of a dynamical loss channel induced by the coupling of the soliton to linear modes near the pump wavelength. In addition, through adjusting the input pulse energy, the central wavelength of blueshifting solitons can be continuously tuned over 300 nm. These experimental results, confirmed by numerical simulations, not only offer a deep insight into ionization-induced soliton-plasma dynamics in gas-filled hollow-core photonic crystal fibers, but also develop highly tunable ultrafast light sources at visible wavelengths, which may have many applications in ultrafast spectroscopy.

Imaging G-Ratio in Multiple Sclerosis Using High-Gradient Diffusion MRI and Macromolecular Tissue Volume

BACKGROUND AND PURPOSE

Remyelination represents an area of great therapeutic interest in multiple sclerosis but currently lacks a robust imaging marker. The purpose of this study was to use high-gradient diffusion MRI and macromolecular tissue volume imaging to obtain estimates of axonal volume fraction, myelin volume fraction, and the imaging g-ratio in patients with MS and healthy controls and to explore their relationship to neurologic disability in MS.

MATERIALS AND METHODS

Thirty individuals with MS (23 relapsing-remitting MS, 7 progressive MS) and 19 age-matched healthy controls were scanned on a 3T MRI scanner equipped with 300 mT/m maximum gradient strength using a comprehensive multishell diffusion MRI protocol. Macromolecular tissue volume imaging was performed to quantify the myelin volume fraction. Diffusion data were fitted to a 3-compartment model of white matter using a spheric mean approach to yield estimates of axonal volume fraction. The imaging g-ratio was calculated from the ratio of myelin volume fraction and axonal volume fraction. Imaging metrics were compared between groups using 2-sided t tests with a Bonferroni correction.

RESULTS

The mean g-ratio was significantly elevated in lesions compared with normal-appearing WM (0.74 vs 0.67, P < .001). Axonal volume fraction (0.17 vs 0.23, P < .001) and myelin volume fraction (0.17 vs 0.25, P < .001) were significantly lower in lesions than normal-appearing WM. Myelin volume fraction was lower in normal-appearing WM compared with that in healthy controls (0.25 vs 0.27, P = .009). Disability, as measured by the Expanded Disability Status Scale, was significantly associated with myelin volume fraction (β = -40.5, P = .001) and axonal volume fraction (β = -41.0, P = .016) in normal-appearing WM.

CONCLUSIONS

The imaging g-ratio may serve as a biomarker for the relative degree of axonal and myelin loss in MS.

Effects of curcumin on the role of MMP-2 in endometrial cancer cell proliferation and invasion

OBJECTIVE

This study aims to investigate the effect of curcumin concentrations on the proliferation and invasion of endometrial cancer cells.

MATERIALS AND METHODS

Endometrial cancer cells were cultured with 0, 15, and 30 μmol/l curcumin, and were divided into control group, low concentration group, and high concentration group. The treatment included the silencing and overexpression of MMP-2. The expression of MMP-2 and E-cadherin were detected by Western blot and the expression level changes were recorded after MMP-2 was silenced and overexpressed. Pearson's analysis was used to determine the relationship of curcumin concentration between MMP-2 mRNA. CCK-8 was used to detect the optical density of cancer cells in three groups. Transwell invasion assay was performed to analyze the invasion inhibition rate in the three groups.

RESULTS

Western blot and qPCR results: MMP-2 expression levels were lower and E-cadherin was higher in high concentration group than that in the low concentration group (p<0.01). MMP-2 protein and mRNA decreased after ShRNA and increased after overexpression (p<0.01). Pearson analysis revealed that the curcumin concentration was negatively correlated with the MMP-2 mRNA (r=-0.497, p=0.036). Cell optical density was lower with curcumin and the lowest was in high concentration group (p<0.01). After MMP-2 silencing, optical cell density decreased and this value increased after overexpression (p=0.000). Cell invasion results: Curcumin improves the rate of cell invasion (p<0.01). After silencing of MMP-2, cell invasion inhibition rate increased, while the invasion inhibition rate decreased after overexpression (p<0.01).

CONCLUSIONS

Curcumin can downregulate MMP-2, inhibit the proliferation and invasion of cancer cells.

Type I interferon and interferon-stimulated gene expression in oral epithelial cells

Oral epithelial cells (OEC) represent the first site of host interaction with viruses that infect the body through the oral route; however, their innate antiviral defense mechanisms yet to be defined. Previous studies have determined that OEC express pathogen-, damage-, or danger-associated molecular patterns (PAMPs or DAMPs), but their expression of key antiviral innate immune mediators, including type I interferons (type I IFN) and interferon-stimulated genes (ISGs) has not been studied extensively. We used the oral keratinocyte cell line, OKF6/TERT1, in the presence and absence of the viral mimics poly(I:C) and unmethylated CpG DNA, to define the expression of type I IFN and ISGs. We identified the basal expression of novel type I IFN genes IFNE and IFNK, while IFNB1 was induced by viral mimics, through the nuclear translocation of IRF3. Numerous ISGs were expressed at basal levels in OEC, with an apparent correlation between high expression and antiviral activity at the earlier stages of viral infection. Stimulation of OECs with poly(I:C) led to selective induction of ISGs, including MX1, BST2, PML, RSAD2, ISG15, and ZC3HAV1. Together, our results demonstrate that OECs exhibit a robust innate antiviral immune defense profile, which is primed to address a wide variety of pathogenic viruses that are transmitted orally.

Complement alternative pathway activation associated with pulmonary hypertension in lupus nephritis patients

Pulmonary hypertension occurs in systemic lupus erythematosus (SLE) for several reasons, such as vasculopathy. Previous studies have indicated that the excessive activation of the complement alternative pathway might be involved in the pathogenesis of lupus nephritis, especially in the absence of factor H or its functional impairment. However, the clinical and pathological significance of the alternative complement activation in lupus nephritis patients with pulmonary hypertension remains elusive. The data on patients with pulmonary hypertension and non-pulmonary hypertension lupus nephritis were retrospectively analyzed in our centre. Major plasma levels of complement components were evaluated. The depositions of Bb, C3d and C5b-9 in the lung specimens of pulmonary hypertension combined with SLE patients were detected by immunofluorescence staining. Among 352 lupus nephritis cases, 24 were diagnosed with pulmonary hypertension and 328 with non-pulmonary hypertension. Higher levels of Bb and lower levels of factor H were detected in the pulmonary hypertension group in comparison with the negative group (P = 0.049, P = 0.024, respectively). Pulmonary hypertension was a risk factor for renal outcome as deduced by the log-rank and Cox test for survival analysis. C3d, C5b-9 and Bb were found to be positive in lung specimens of lupus nephritis patients with pulmonary hypertension. We concluded that activation of the complement alternative pathway may be involved in the pathogenesis of pulmonary hypertension in lupus nephritis.

Effect of Hypotensive Brain Death on the Donor Liver and Its Mechanism in an Improved Bama Miniature Pig (Sus scrofa domestica) Model

BACKGROUND

We aimed to observe the effect of hypotensive brain death on the donor liver and understand its pathophysiological mechanism in improved pig model.

METHODS

The model was induced using the modified intracranial water sac inflation method in 16 Bama miniature pigs. Effects of hypotensive brain death on liver function and tissue morphology were evaluated via changes in liver function enzyme index, liver tissue alkaline phosphatase levels, hourly bile flow, and liver tissue pathology. Its pathophysiological mechanism was examined on the basis of changes in portal vein blood flow, hepatic artery blood flow, portal venous endotoxin level, and liver tissue cytokine levels.

RESULTS

After model establishment, portal vein blood flow, hepatic arterial blood flow, hourly bile flow, and alkaline phosphatase content in hepatic tissue significantly decreased, and serum aspartate aminotransferase, alkaline phosphatase, and lactate dehydrogenase levels significantly increased. Hematoxylin-eosin staining of liver tissue showed that after model establishment, hepatic tissue injury was gradually aggravated and hepatic cells were irreversibly damaged at 7 hours. Portal vein endotoxin levels significantly increased after brain death. Tumor necrosis factor α, interleukin 1, and endothelin 1 levels in liver tissues significantly increased at 3, 6, and 12 hours after brain death (P < .05), and hypoxia-inducible factor 1-α and nitric oxide levels significantly decreased (P < .05).

CONCLUSIONS

Hepatic injury was progressively aggravated under hypotensive brain death. The mechanism of donor liver injury under hypotensive brain death may involve low liver perfusion, release of intestinal endotoxin and inflammatory factors (eg, tumor necrosis factor α and interleukin 1), decreased hypoxia-inducible factor 1-α, and endothelin 1 and nitric oxide imbalance.