N enrichment affects the arbuscular mycorrhizal fungi-mediated relationship between a C4 grass and a legume

Arbuscular mycorrhizal fungi (AMF) regulate soil nutrient cycling, directly supplying a host plant with nitrogen (N). AMF can also affect the outcome of interspecific interactions, but a mechanistic understanding of how soil N availability affects AMF-mediated interspecific relationships is currently lacking. We selected one dominant (Bothriochloa ischaemum; C₄ grass) and one subordinate (Lespedeza davurica; legume) species in a natural grassland climax community to investigate the mechanism by which AMF influence interspecific interaction (mixed and monoculture) under three levels of N addition (0, low, and high N addition). Under the non-N addition treatment, AMF preferentially supplied N to the roots of B. ischaemum at the expense of N uptake by L. davurica, resulting in inhibited AMF benefits for L. davurica shoot growth. Under the low N addition treatment, interspecific interaction via AMF promoted L. davurica growth. Compared to the non-N addition treatment, N addition largely mitigated the effects, both positive (for B. ischaemum) and negative (for L. davurica), of AMF-mediated interspecific interaction on plant N uptake via AMF. When soil N availability severely limited plant growth, preferential N supply to the C₄ grass by AMF was important for maintaining the abundance of the dominant species. When the N limitation for plant growth was alleviated by N addition, the interaction between AMF and soil microorganisms improved nutrient availability for the legume by stimulating activity of the enzyme responsible for soil organic matter mineralization, which is important for maintaining the abundance of the subordinate species. These data could influence strategies for maintaining biodiversity.     

Elevated Progesterone Levels on the Day of Oocyte Maturation May Affect Top Quality Embryo IVF Cycles

In contrast to the impact of elevated progesterone on endometrial receptivity, the data on whether increased progesterone levels affects the quality of embryos is still limited. This study retrospectively enrolled 4,236 fresh in vitro fertilization (IVF) cycles and sought to determine whether increased progesterone is associated with adverse outcomes with regard to top quality embryos (TQE). The results showed that the TQE rate significantly correlated with progesterone levels on the day of human chorionic gonadotropin (hCG) trigger (P = 0.009). Multivariate linear regression analysis of factors related to the TQE rate, in conventional IVF cycles, showed that the TQE rate was negatively associated with progesterone concentration on the day of hCG (OR was -1.658, 95% CI: -2.806 to -0.510, P = 0.005). When the serum progesterone level was within the interval 2.0–2.5 ng/ml, the TQE rate was significantly lower (P <0.05) than when the progesterone level was < 1.0 ng/ml; similar results were obtained for serum progesterone levels >2.5 ng/ml. Then, we choose a progesterone level at 1.5ng/ml, 2.0 ng/ml and 2.5 ng/ml as cut-off points to verify this result. We found that the TQE rate was significantly different (P <0.05) between serum progesterone levels < 2.0 ng/ml and >2.0 ng/ml. In conclusion, the results of this study clearly demonstrated a negative effect of elevated progesterone levels on the day of hCG trigger, on TQE rate, regardless of the basal FSH, the total gonadotropin, the age of the woman, or the time of ovarian stimulation. These data demonstrate that elevated progesterone levels (>2.0 ng/ml) before oocyte maturation were consistently detrimental to the oocyte.     

Augmentation of Autoantibodies by Helicobacter pylori in Parkinson’s Disease Patients May Be Linked to Greater Severity

Parkinson''s disease (PD) is the second most common chronic and progressive neurodegenerative disorder. Its etiology remains elusive and at present only symptomatic treatments exists. Helicobacter pylori chronically colonizes the gastric mucosa of more than half of the global human population. Interestingly, H. pylori positivity has been found to be associated with greater of PD motor severity. In order to investigate the underlying cause of this association, the Sengenics Immunome protein array, which enables simultaneous screening for autoantibodies against 1636 human proteins, was used to screen the serum of 30 H. pylori-seropositive PD patients (case) and 30 age- and gender-matched H. pylori-seronegative PD patients (control) in this study. In total, 13 significant autoantibodies were identified and ranked, with 8 up-regulated and 5 down-regulated in the case group. Among autoantibodies found to be elevated in H. pylori-seropositive PD were included antibodies that recognize Nuclear factor I subtype A (NFIA), Platelet-derived growth factor B (PDGFB) and Eukaryotic translation initiation factor 4A3 (eIFA3). The presence of elevated autoantibodies against proteins essential for normal neurological functions suggest that immunomodulatory properties of H. pylori may explain the association between H. pylori positivity and greater PD motor severity.     

动脉内灌药,内支架安置双介入治疗十二指肠恶性梗阻

通过动脉内灌药,内支架安置双介入治疗提高对十二指肠恶性梗阻姑息性治疗的疗效。十二指肠恶性梗阻病例１４例,男５例,女９例,年龄２０－６９岁,经口安置自膨式十二指肠金属支架共１５枚,其中１２例在支架安置后定期行肿瘤供血动脉插管介入化疗,所有病例梗阻症状解除,２例未行动脉灌药治疗者分别于２个月及４个月死亡,１２例双介入者生存期明显延长,最短６月,最长已达一年,结论：双介入治疗能够姑息治疗疗效延长晚期瘤患     

Signaling Molecule Methylglyoxal Remits the Toxicity of Plumbum by Modifying Antioxidant Enzyme and Osmoregulation Systems in Wheat (Triticum aestivum L.) Seedlings

Russian Journal of Plant Physiology - Methylglyoxal (MG) has traditionally been known as a toxic byproduct of cellular metabolism in plants, which now has been found to function as a novel...     

One-step "green" preparation of graphene nanosheets and carbon nanospheres mixture by electrolyzing graphite rob and its application for glucose biosensing

The graphene nanosheets and carbon nanospheres mixture (GNS–CNS) was prepared by electrolyzing graphite rob in KNO₃ solution under constant current, which was characterized by TEM, AFM, SEM, FT-IR, XRD, XPS, TGA and UV–vis. The nano-mixture can keep stable in water for more than one month. Based on this kind of mixture material, a novel electrochemical biosensing platform for glucose determination was developed. Cyclic voltammetry of glucose oxidase (GOD) immobilized on GNS–CNS/GCE exhibited a pair of well-defined quasi-reversible redox peaks at −0.488 V (E_pa) and −0.509 V (E_pc) by direct electron transfer between the protein and the electrode. The charge-transfer coefficient (α) was 0.51, the electron transfer rate constant was 2.64 s⁻¹ and the surface coverage of HRP was 3.18 × 10⁻¹⁰ mol cm⁻². The immobilized GOD could retain its bioactivity and catalyze the reduction of dissolved oxygen. The glucose biosensor has a linear range from 0.4 to 20 mM with detection limit of 0.1 mM. Moreover, the biosensor exhibits acceptable reproducibility and storage stability. The fabricated biosensor was further used to determine glucose in human plasma sample with the recoveries from 96.83% to 105.52%. Therefore, GOD/GNS–CNS/GCE could be promisingly applied to determine blood sugar concentration in the practical clinical analysis.