痛泻要方对“肝气乘脾”泄泻小鼠肠黏膜及肠内容物消化酶活性的影响

目的探讨痛泻要方对"肝气乘脾"泄泻小鼠肠道酶活性的影响。方法采用"番泻叶-离心管束缚夹尾法"进行"肝气乘脾"泄泻造模,造模成功后以痛泻要方治疗,造模和治疗后分别分析小鼠肠道酶活性。结果造模后,模型组小鼠肠道内容物的淀粉酶活性显著降低(t=4.007,P=0.015),纤维素酶、蛋白酶、蔗糖酶活性下降不显著。模型组小鼠肠黏膜蛋白酶、淀粉酶、蔗糖酶活性显著下降(t_蛋=5.652,P=0.005;Z_淀=-1.964,P=0.050;t_蔗=4.737,P=0.009)。痛泻要方治疗后,中药干预组小鼠肠道内容物蛋白酶、纤维素酶、乳糖酶和蔗糖酶活性变化不显著;自然恢复组的淀粉酶活性显著高于正常组(t=-7.497,P=0.002)。中药干预组小鼠肠道前段黏膜蛋白酶、乳糖酶、淀粉酶、蔗糖酶活性恢复不显著;中药干预组小鼠肠道黏膜中段乳糖酶、蔗糖酶活性显著低于自然恢复组(t_乳=4.074,P=0.013;t_蔗=8.072,P0.001),而蛋白酶、淀粉酶及纤维素酶活性均高于自然恢复组;中药干预组小鼠肠道后段黏膜乳糖酶、蔗糖酶及淀粉酶活性显著高于正常组(t_乳=-7.962,P0.001;t_蔗=-15.921,P0.001;Z_淀=6.489,P=0.034),蛋白酶与纤维素酶活性均有所升高。结论 "肝气乘脾"泄泻肠道内容物及黏膜淀粉酶活性显著降低,痛泻要方对"肝气乘脾"泄泻小鼠肠黏膜乳糖酶、蔗糖酶及淀粉酶活性作用显著。     

Leishmania infantum: mixed T-helper-1/T-helper-2 immune response in experimentally infected BALB/c mice

The main goal of the present study was to characterise the course of infection and immunological responses developed by Leishmania infantum infected BALB/c mice. Parasite load was determined by Real-time TaqMan PCR while cytokine and Immunoglobulin G (IgG) production were assessed by ELISA. Leishmania DNA was detected in spleen and liver as soon as day 1 post-inoculation (pi) and the parasitism was sustained until the end of the experiment. The cytokine kinetics in spleen and liver was generally associated with the oscillations of parasite load. Overall, it was not observed a distinct Th1 or Th2 pattern of cytokine production during the time of experiment. The infected mice developed a mixed immune response, with concomitant production of IFN-gamma, IL-4 and IL-10, both in spleen and liver, and both IgG isotypes. However, our results suggest that, compared to liver, the spleen is more susceptible to L. infantum infection.     

Nippostrongylus brasiliensis: reversibility of reduced-energy status associated with the course of expulsion from the small intestine in rats

Gastrointestinal nematodes require energy for active establishment in the gut against intestinal flow and peristaltic motion. In this study we employed CellTiter-Glo Luminescent Cell Viability Assay to measure the ATP value of individual adult Nippostrongylus brasiliensis during the course of immune-mediated expulsion from the small intestine in rats. The ATP values of adult worms taken from the lumen of the distal small intestine were lower than worms collected from the lumen of the proximal small intestine. Moreover, values from worms in the lumen of the proximal small intestine were lower than those from worms in the mucosa, the preferred site of adult N. brasiliensis. The reduction of ATP values in worms from each region was observed not only at expulsion phase, but also at established phases of the infection suggesting that energy metabolism of the parasites is independent of host immune response. When adult worms with low ATP values on day 12 post-infection were implanted surgically into the small intestine of na?ve rats, the worms re-established in recipients and completely restored the ATP values. Short in vitro culture of adult worms under low oxygen tension resulted in low ATP value in the worms. These results suggested that adult worms were dislodged from their preferred site by intact energy metabolism activity.     

The response of alpha-amylase activity during wheat grain development to nitrogen fertiliser

The aim of this study was to test whether the effect of nitrogen fertiliser on Hagberg falling number of winter wheat (Triticum aestivum) grain in the absence of sprouting is mediated by pre-maturity alpha-amylase activity and is related to grain drying rate. A field experiment with two cultivars (Avalon and Mercia) in 1990 and 1991 compared four application rates of nitrogen. Samples of grain were taken at intervals during development for moisture determination and alpha-amylase assay. Grains from plots given nitrogen dried faster in both years, but alpha-amylase activity and Hagberg falling number responded differently to nitrogen in the two years. In the warmer and drier year of 1990, alpha-amylase activity declined throughout development leading to very high Hagberg falling number at harvest, with little effect of nitrogen. In the cooler and wetter year of 1991, alpha-amylase activity declined until about 30% moisture. After this stage, alpha-amylase activity increased in the absence of sprouting in grain from plots receiving little or no nitrogen. This resulted in a linear increase in Hagberg falling number in response to nitrogen fertiliser. Electrophoresis of alpha-amylase isozymes indicated that the increase in Hagberg falling number in response to nitrogen was not mediated by a decrease in retained pericarp alpha-amylase activity, but by a reduction in pre-maturity alpha-amylase activity. These results support the hypothesis that slow grain drying enhances pre-maturity alpha-amylase formation, and also support the hypothesis that an additional environmental factor varying between seasons is involved in pre-maturity alpha-amylase formation.     

A Study of Glutathione <Emphasis Type="Italic">S</Emphasis>-transferase pi Expression in Central Nervous System of Subjects with Amyotrophic Lateral Sclerosis Using RNA Extraction from Formalin-Fixed,Paraffin-Embedded Material

The expression of glutathione S-transferase pi (GST pi), an enzyme responsible for inactivation of a large variety of toxic compounds was studied in spinal cord, motor and sensory brain cortex obtained from patients who died in the course of amyotrophic lateral sclerosis (ALS). The studies were performed on formalin-fixed, paraffin-embedded (FFPE) and freshly frozen tissues. The method of RNA isolation from FFPE was modified. A significant decrease of GST pi-mRNA expression was found in cervical spinal cord and motor brain cortex of ALS subjects comparing to analogue control tissues (P < 0.01), as well as in motor cortex of ALS subjects comparing to their sensory cortex (P < 0.05). In spinal cords the decrease in GST pi-mRNA expression was accompanied by a decrease of GST pi protein level. Results indicated lowered GST pi expression on both mRNA and protein levels in the regions of nervous system affected by ALS. The non-properly inactivated by GST toxic electrophiles and organic peroxides may thus contribute to motor neurons damage.     

Directed evolution to low nanomolar affinity of a tumor-targeting epidermal growth factor receptor-binding affibody molecule

The epidermal growth factor receptor 1 (EGFR) is overexpressed in various malignancies and is associated with a poor patient prognosis. A small, receptor-specific, high-affinity imaging agent would be a useful tool in diagnosing malignant tumors and in deciding upon treatment and assessing the response to treatment. We describe here the affinity maturation procedure for the generation of Affibody molecules binding with high affinity and specificity to EGFR. A library for affinity maturation was constructed by rerandomization of selected positions after the alignment of first-generation binding variants. New binders were selected with phage display technology, using a single oligonucleotide in a single-library effort, and the best second-generation binders had an approximately 30-fold improvement in affinity (K_d = 5-10 nM) for the soluble extracellular domain of EGFR in biospecific interaction analysis using Biacore. The dissociation equilibrium constant, K_d, was also determined for the Affibody with highest affinity using EGFR-expressing A431 cells in flow cytometric analysis (K_d = 2.8 nM). A retained high specificity for EGFR was verified by a dot blot assay showing staining only of EGFR proteins among a panel of serum proteins and other EGFR family member proteins (HER2, HER3, and HER4). The EGFR-binding Affibody molecules were radiolabeled with indium-111, showing specific binding to EGFR-expressing A431 cells and successful targeting of the A431 tumor xenografts with 4-6% injected activity per gram accumulated in the tumor 4 h postinjection.     

Deciphering structural stability and binding mechanisms of potential antagonists with smoothened protein

Identification of new potential inhibitors against Hedgehog pathway activator protein Smoothened (SMO) is considered to be of higher importance to improvise the future cancer therapeutics. Different SMO inhibitors/drugs (e.g. Cyclopamine, Vismodegib, Taladegib) used till date are found to be associated with several drug-related resistivity and toxicity. To explore the ability of new drug/inhibitor molecules, which can show better/similar binding and dynamic stability as compared to known inhibitors, virtual screening against SMO is performed followed by the comparative docking and molecular dynamic studies. ‘ZINC12368305’ is found to be the best molecule among the entire data-set, as it shows the highest binding affinity and stable conformations. Here, an integrative approach using Dynamic Graph Theory is introduced to gain the molecular insights of the structural integrity of these protein complexes at the residue level by analyzing the corresponding Protein Contact Networks along the Molecular Dynamics trajectories. The study further focuses to understand the detailed binding mechanisms of available inhibitor/drug molecules along with the newly predicted molecule. It is observed that a unique big cluster of low fluctuating residues at the vicinity of the drug binding pocket of the SMO in ZINC12368305-bound complex is present and driving it toward a more stable region. A close inspection on this site reveals the presence of a stable Pi–Pi interaction between the pyrazole group-associated phenanthrene ring of ZINC12368305 and aromatic ring of Phe484 of SMO, which could be the potential factor of ZINC12368305 to create a more stable complex with SMO as compared to the other inhibitors.     

The crystal structure of archaeal serine hydroxymethyltransferase reveals idiosyncratic features likely required to withstand high temperatures

Serine hydroxymethyltransferases (SHMTs) play an essential role in one‐carbon unit metabolism and are used in biomimetic reactions. We determined the crystal structure of free (apo) and pyridoxal‐5′‐phosphate‐bound (holo) SHMT from Methanocaldococcus jannaschii, the first from a hyperthermophile, from the archaea domain of life and that uses H₄MPT as a cofactor, at 2.83 and 3.0 Å resolution, respectively. Idiosyncratic features were observed that are likely to contribute to structure stabilization. At the dimer interface, the C‐terminal region folds in a unique fashion with respect to SHMTs from eubacteria and eukarya. At the active site, the conserved tyrosine does not make a cation‐π interaction with an arginine like that observed in all other SHMT structures, but establishes an amide‐aromatic interaction with Asn257, at a different sequence position. This asparagine residue is conserved and occurs almost exclusively in (hyper)thermophile SHMTs. This led us to formulate the hypothesis that removal of frustrated interactions (such as the Arg‐Tyr cation‐π interaction occurring in mesophile SHMTs) is an additional strategy of adaptation to high temperature. Both peculiar features may be tested by designing enzyme variants potentially endowed with improved stability for applications in biomimetic processes. Proteins 2014; 82:3437–3449. © 2014 Wiley Periodicals, Inc.     

Association of glutathione S-transferase M1/T1 polymorphisms with susceptibility to vitiligo

Background

Some studies suggested that Glutathione S-transferases M1/T1(GSTM1/T1) null polymorphisms may be associated with the risk of vitiligo.

Aims

The purpose of this study is to further evaluate the association between GSTM1/T1 null polymorphisms and the susceptibility to vitiligo.

Methods

We carried out a retrieval of studies in the databases. Odds ratios (OR) and 95% confidence intervals (95% CIs) were used to assess the strength of this association. We analyzed the data using Stata 11.0.

Results

Six case–control studies including 1358 cases and 1673 controls were included in this meta-analysis. Our overall results showed the GSTM1 or GSTT1 null polymorphism was associated with vitiligo (GSTM1:OR = 1.59, 95% CI: 1.21–2.08, P = 0.001; GSTT1: OR = 1.30, 95% CI: 1.12–1.51, P = 0.001). In the subgroup analysis, the GSTM1 null polymorphism might be a genetic risk factor to vitiligo in East Asian (OR = 1.71, 95% CI: 1.12–2.63, P = 0.014) but not in the Mediterranean, however individuals with the GSTT1 null polymorphism in the Mediterranean (OR = 1.76, 95% CI: 1.15–2.71, P = 0.010) but not in East Asian have a greater predisposition to vitiligo. In addition there was also a significant trend toward an association with the combination of the GSTM1 null and GSTT1 null in either East Asians or Mediterraneans.

Conclusion

The GSTM1/T1 null polymorphisms may be associated with vitiligo. More studies are needed to confirm this conclusion.