Switching and Rectification of a Single Light-sensitive Diarylethene Molecule Sandwiched between Graphene Nanoribbons

The 'open' and 'closed' isomers of the diarylethene molecule that can be converted between each other upon photo-excitation are found to have drastically different current-voltage characteristics when sandwiched between two graphene nanoribbons (GNRs). More importantly, when one GNR is metallic and another one is semiconducting, strong rectification behavior of the 'closed' diarylethene isomer with the rectification ratio >10^3 is observed. The surprisingly high rectification ratio originates from the band gap of GNR and the bias-dependent variation of the lowest unoccupied molecular orbital (LUMO) of the diarylethene molecule, the combination of which completely shuts off the current at positive biases. Results presented in this paper may form the basis for a new class of molecular electronic devices.Comment: The Journal of Chemical Physics 135 (2011

In vitro culture method of powdery mildew (Oidium heveae Steinmann) of Hevea brasiliensis

A method for culturing powdery mildew (Oidium heveae) from isolated leaves of Hevea brasiliensis was evaluated, which included three steps: Leaves and fungi selection, nutrient solution and culture dish  preparation, fungi inoculation and culture. The culture time and produced conidia number were considered as decision index. We tested the influence of micro components of nutrient solution including 6-benzylaminopurine (6-BA), salicylic acid (SA) and vitamin C (VC) and evaluated the culture difference of various leaf phenological phases and rubber tree clones. The results show that the longest culture time of isolated leaves emerged on modified Murashige and Skoog (MS) macro elements with 4 mg/L 6-BA, 20 mg/L SA, 1 mg/L VC. The colour phase leaf was the preferable choice for culturing average 15 to 16 days and producing 3.2222 × 106 mL-1 conidia. The culture effects of using various rubber clones were different and higher resistance clones cultured less conidia. The method leading to mass production of powdery mildew was simple using a climate incubator to resolve problems linked to season and space limitation and preservation of powdery mildew. This method could improve rubber resistance breeding process.Key words: Hevea brasiliensis, Oidium heveae, in vitro culture, nutrient solution, phenological phase

Determination of Content of 6 Triterpenic Acids in Malusdoumeri Fruit by High-performance Liquid Chromatography

A HPLC method was developed for the simultaneous determination of euscaphic acid, 2α,19α-dihydroxy-3-oxo-urs-12-en-28-oic acid, maslinic acid, corosolic acid, oleanic acid, and ursolic acid in Malus doumeri fruits. Analyses were conducted on the distribution and content of these six triterpenic acids in Malus doumeri fruits from six producing areas in Guangxi. Using gradient elution at a flow rate of 0.8 mL/min, a Diamonsil C18 (2) column was used with a mobile phase of 0.1% formic acid aqueous solution/methanol (v/v). The detection wavelength was 210 nm and the column temperature was 30 ℃. The results showed that the mass concentrations of the six triterpenic acids had a good linear relationship with the chromatographic peak areas in the linear range. The correlation coefficients were greater than 0.9990, the detection limits were within 0.46~2.00 μg/mL, the lower quantitation limits were within 1.53~6.67 μg/mL, the coefficients of variation were less than 5.0%, and the recovery percentages were within 99.2%~101.3%. Six samples from different production areas contained six triterpenic acids (euscaphic acid, 2α,19α-dihydroxy-3-oxo-urs-12-en-28-oic acid, maslinic acid, corosolic acid, oleanic acid, and ursolic acid). Each of the six triterpenic acids was a pentacyclic triterpenic acid. Among the six triterpenic acids, euscaphic acid and 2α,19α-dihydroxy-3-oxo-urs-12-en-28-oic acid were first detected in Malus doumeri fruits. Ursolic acid, euscaphic acid, and 2α,19α-dihydroxy-3-oxo-urs-12-en-28-oic acid were predominant, accounting for 71.82%~81.38% of the total triterpenic acids. The total triterpenic acids content ranged from 808.74 to 1090.75 μg/g FM. The total triterpenic acids content of fruits from Liujiang district of Liuzhou and Pingle of Guilin were relatively high, reaching 1090.75 μg/g FM and 1045.20 μg/g FM, respectively. Overall, this study's HPLC method can detect the triterpenic acids content of Malus doumeri fruits and provide scientific references for the quality evaluation of Malus doumeri fruit's raw materials and products

EXTRACTION AND ISOLATION OF ALKALOIDS OF SOPHORA ALOPECUROIDES AND THEIR ANTI-TUMOR EFFECTS IN H22 TUMOR-BEARING MICE

Background: Alkaloids of Sophora alopecuroides have good biological activity, and are widely used in clinical settings, which not only have pharmacological activities of anti-cancer, cancer suppression, as well as the inhibition, and killing of various microorganisms; but also possess extensive pharmacological effects on immune system, nervous system and cardiovascular system. The objective of this paper was to extract and isolate total alkaloids of Sophora alopecuroides (TASA), and to study their anti-tumor effects in H22 tumor-bearing mice. Materials and Methods: TASA were extracted and isolated using thin-layer chromatography, and column chromatography; and the isolated compounds were analyzed using nuclear magnetic resonance. The inhibitory effects of TASA on tumor in H22-bearing mice were determined by MTT assay. Results: Three compounds were isolated from Sophora alopecuroides L., which were matrine, oxymatrine and sophoridine, respectively. Meanwhile, mouse H22 sarcoma model was established and different doses of TASA apparently inhibited solid H22-tumor in mice; it inhibited the thymus, and spleen to some extent; the degree of inhibition was more obvious for the spleen. Conclusion: TASA has an anti-tumor effect in H22 tumor-bearing mice

Zinc inhibits TRPV1 to alleviate chemotherapy-induced neuropathic pain

Zinc is a transition metal that has a long history of use as an anti-inflammatory agent. It also soothes pain sensations in a number of animal models. However, the effects and mechanisms of zinc on chemotherapy-induced peripheral neuropathy remain unknown. Here we show that locally injected zinc markedly reduces neuropathic pain in male and female mice induced by paclitaxel, a chemotherapy drug, in a TRPV1-dependent manner. Extracellularly applied zinc also inhibits the function of TRPV1 expressed in HEK293 cells and mouse DRG neurons, which requires the presence of zinc-permeable TRPA1 to mediate entry of zinc into the cytoplasm. Moreover, TRPA1 is required for zinc-induced inhibition of TRPV1-mediated acute nociception. Unexpectedly, zinc transporters, but not TRPA1, are required for zinc-induced inhibition of TRPV1-dependent chronic neuropathic pain produced by paclitaxel. Together, our study demonstrates a novel mechanism underlying the analgesic effect of zinc on paclitaxel-induced neuropathic pain that relies on the function of TRPV1

Role of OCT4 in cisplatin treatment of testicular embryonal carcinoma

Purpose: To determine the role of embryonal transcription factor OCT4 in cisplatin treatment of testicular embryonal carcinoma.Methods: In vitro assays were employed to assess the effect of cisplatin treatment on testicular embryonal carcinoma cell lines under OCT4 silencing. Following treatment with 500 ng/μL cisplatin, MTT assay was used to examine cell proliferation of 2012-EP and 833K-E cells with or without OCT silencing, while wound healing assay was used to examine cell migration ability. Transwell assay and crystal violet staining were employed to measure cell invasive capacity, whereas the distribution pattern of cell cycle was assessed by flow cytometry. The expression levels of several critical components in tumorigenicity related pathways with or without OCT silencing were determined by Western-blot analysis.Results: Cisplatin enhanced OCT4-silenced cell viability at all concentration (p < 0.01) when compared to control cells. Upon treatment with 500 ng/μL cisplatin, OCT4-silenced cells showed 2- to 3-fold enhancement in cell proliferation (p < 0.001), 2-fold increase in cell migration capacity (p < 0.001), and about 1.5-fold enhancement in invasive capacity (p < 0.001) when compared to control cells. In addition, OCT4 silencing upregulated the expression level of the proteins involved in cell proliferation, cell mobility, cancer metastasis and cell cycle control.Conclusion: The results suggest that OCT4 may serve as a therapeutic target for testicular embryonal carcinoma treatment in combination with cisplatin by modulating OCT4 expression level. This physiological evidence indicates that OCT4 downregulation contributes to cisplatin resistance in chemotherapy and subsequent disease relapse.Keywords: OCT4, Cisplatin resistance, Testicular embryonal carcinoma, Chemotherap

Mass spectrometry-based metabolomics for discovering active ingredients and exploring action mechanism of herbal medicine

Natural products derived from herbal medicine are a fruitful source of lead compounds because of their structural diversity and potent bioactivities. However, despite the success of active compounds derived from herbal medicine in drug discovery, some approaches cannot effectively elucidate the overall effect and action mechanism due to their multi-component complexity. Fortunately, mass spectrometry-based metabolomics has been recognized as an effective strategy for revealing the effect and discovering active components, detailed molecular mechanisms, and multiple targets of natural products. Rapid identification of lead compounds and isolation of active components from natural products would facilitate new drug development. In this context, mass spectrometry-based metabolomics has established an integrated pharmacology framework for the discovery of bioactivity-correlated constituents, target identification, and the action mechanism of herbal medicine and natural products. High-throughput functional metabolomics techniques could be used to identify natural product structure, biological activity, efficacy mechanisms, and their mode of action on biological processes, assisting bioactive lead discovery, quality control, and accelerating discovery of novel drugs. These techniques are increasingly being developed in the era of big data and use scientific language to clarify the detailed action mechanism of herbal medicine. In this paper, the analytical characteristics and application fields of several commonly used mass spectrometers are introduced, and the application of mass spectrometry in the metabolomics of traditional Chinese medicines in recent years and its active components as well as mechanism of action are also discussed

Pathological Changes and Expression of JAK-STAT Signaling Pathway Hallmark Proteins in Rat Retinas at Different Time Points After Retinal Ischemia Reperfusion Injury

Retinal ischemia reperfusion injury (RIRI) is a conventional pathological process in various retinal vascular diseases. Many studies select only one specific time point to apply drugs and then assess the therapeutic effect of drugs; however, the baselines are not the same at different time points, which may cause variation in the judgement. Therefore, further investigation is needed. Accordingly, this study aimed to investigate the pathological changes of retinal structure, expression of JAK-STAT signaling pathway hallmark proteins, and apoptosis at different time points after retinal ischemia reperfusion injury in rats. Sixty-six male SPF Sprague-Dawley rats were randomly divided into six groups: control group, RIRI 0, 6-, 24-, 72-, and 144-h groups. RIRI models were induced by perfusing equilibrium solution into the right eye anterior chamber to increase intraocular pressure to 110 mmHg for 60 min. Rats were sacrificed at different time points after reperfusion. Then hematoxylin-eosin staining, transmission electron microscope, immunohistochemistry, western blot, and TUNEL were used. Hematoxylin-eosin showed the pathological changes while transmission electron microscope revealed the ultra-structure changes of retina after RIRI. Immunohistochemistry showed that JAK2, STAT3, p-JAK2, p-STAT3, Bax, and Bcl-2 proteins mainly located in ganglion cell layer and inner nuclear layer, the relative expression of former five proteins had significant differences vs. control group (p < 0.05), while Bcl-2 had no significant difference. In western blot, the protein expressing of JAK2, STAT3, p-JAK2, p-STAT3, p-Akt, and Bax had significant differences vs. control group (p < 0.05), while Akt and Bcl-2 had no significant differences. TUNEL staining showed the number of apoptosis positive cells rose initially but declined later, with a peak value at RIRI 24 h group. The dynamic changes of hallmark proteins at different time points after RIRI indicate that JAK-STAT signaling pathway activates rapidly but weakens later and plays a vital role in RIRI, and apoptosis is involved in RIRI with a peak value at 24 h in the process, suggesting a potential therapeutic direction and time window for treating RIRI

Regional and Cellular Mapping of Sortilin Immunoreactivity in Adult Human Brain

Sortilin is a member of the vacuolar protein sorting 10 protein (VPS10P) domain receptor family, which carries out signal transduction and protein transport in cells. Sortilin serves as the third, G-protein uncoupled, receptor of neurotensin that can modulate various brain functions. More recent data indicate an involvement of sortilin in mood disorders, dementia and Alzheimer-type neuropathology. However, data regarding the normal pattern of regional and cellular expression of sortilin in the human brain are not available to date. Using postmortem adult human brains free of neuropathology, the current study determined sortilin immunoreactivity (IR) across the entire brain. Sortilin IR was broadly present in the cerebrum and subcortical structures, localizing to neurons in the somatodendritic compartment, but not to glial cells. In the cerebrum, sortilin IR exhibited differential regional and laminar patterns, with pyramidal, multipolar and polymorphic neurons in cortical layers II–VI, hippocampal formation and amygdaloid complex more distinctly labeled relative to GABAergic interneurons. In the striatum and thalamus, numerous small-to-medium sized neurons showed light IR, with a small group of large sized neurons heavily labeled. In the midbrain and brainstem, sortilin IR was distinct in neurons at the relay centers of descending and ascending neuroanatomical pathways. Dopaminergic neurons in the substantia nigra, cholinergic neurons in the basal nuclei of Meynert and noradrenergic neurons in the locus coeruleus co-expressed strong sortilin IR in double immunofluorescence. In comparison, sortilin IR was weak in the olfactory bulb and cerebellar cortex, with the mitral and Purkinje cells barely visualized. A quantitative analysis was carried out in the lateral, basolateral, and basomedial nuclei of the amygdaloid complex, as well as cortical layers II–VI, which established a positive correlation between the somal size and the intensity of sortilin IR among labeled neurons. Together, the present study demonstrates a predominantly neuronal expression of sortilin in the human brain with substantial regional and cell-type variability. The enriched expression of sortilin in pyramidal, dopaminergic, noradrenergic and cholinergic neurons suggests that this protein may be particularly required for signal transduction, protein trafficking and metabolic homeostasis in populations of relatively large-sized projective neurons