Microbial transformation of the sesquiterpenoid (-)-maalioxide by Mucor plumbeus

Microbial transformation of the sesquiterpenoid (-)-maalioxide by the fungus Mucor plumbeus gave three metabolites, 9beta-hydroxymaalioxide, 1beta-hydroxymaalioxide and 7beta-hydroxymaalioxide. 9beta-hydroxymaalioxide and its structure was established on the basis of its spectroscopic properties and chemical reactions.     

Oxidative Stress in the Liver of Mice Caused by Intraperitoneal Injection with Lanthanoides

In order to study the mechanisms underlying the effects of lanthanoid (Ln) on the liver, ICR mice were injected with LaCl₃, CeCl₃, and NdCl₃ at a dose of 20 mg/kg BW into the abdominal cavity daily for 14 days. We then examined oxidative stress-mediated responses in the liver. The increase of lipid peroxide in the liver produced by Ln suggested an oxidative attack that was activated by a reduction of antioxidative defense mechanisms as measured by analyzing the activities of superoxide dismutase, catalase, and ascorbate peroxidase, as well as antioxidant levels such as glutathione and ascorbic acid, which were greatest in Ce³⁺ treatment, medium in Nd³⁺, and least in La³⁺. Our results also implied that the oxidative stress in the liver caused by Ln likely is Ce³⁺ > Nd³⁺ >La³⁺, but the mechanisms need to be further studied in future.     

pEGFP-N1-mediated BmK CT expression suppresses the migration of glioma

Gliomas can diffuse into the normal brain and this invasion of glioma cells involves modification of receptor-mediated adhesive properties of tumor cells, degradation and remodeling of extracellular matrix by tumor-secreted metalloproteinase (MMPs) such as MMP-2, consequently creating an intercellular space for invasion of glioma cells. BmK CT, one of the key toxins in scorpion Buthus martensii Karsch venom, is a novel blocker of the chloride ion channel and MMP-2. In this report, a recombinant plasmid pEGFP-N1-BmK CT was constructed and characterized by in vitro studies. The results showed that pEGFP-N1 mediated BmK CT expression displayed a high activity in suppressing cell migration via MMP-2. The potential therapeutic effect of pEGFP-N1 mediated BmK CT against rat glioma C6 cells was assessed and its potential mechanism was elucidated. It represented an approach for developing a novel therapeutic agent—recombinant plasmid pEGFP-N1-BmK CT as an efficient and powerful adjuvant.     

Prostaglandin involvement in follicle-stimulating hormone-induced proliferation of granulosa cells from chicken prehierarchical follicles

The aim of the present study was to evaluate the role of prostaglandin (PG) on proliferation of granulosa cells from prehierarchical small yellow follicles (SYF) of buff laying hens. The granulosa layers were separated by mechanic method and dispersed into single cells. After 16 h pre-incubation in 0.5% FCS medium, the medium was replaced with serum-free medium, which was supplemented with 10 microg/ml insulin, 5 microg/ml transferrin and 3 x 10(-8)M selenite. Cells were challenged with PGE1 and FSH for 24 h and then assessed for proliferation. The results showed that PGE(1) (0.1-10 ng/ml) had a similar proliferating effect as FSH on granulosa cells, and these stimulating effects were restrained by the PGE receptor antagonist SC19220 at 10(-7) to 10(-5)M. Prostaglandin synthase antagonist indomethacin (10(-7) to 10(-5)M) suppressed FSH-induced increase in the number of granulosa cells in a dose-dependent manner. Downstream activation of protein kinase A by forskolin-activated adenylate cyclase resulted in elevated proliferation of granulosa cells, an effect unobserved by phorbol-12-myristrate-13-acetate-activated protein kinase C. In addition, PGE1-stimulated proliferation of granulosa cells was hindered by H89 (PKA inhibitor) but not by H7 (PKC inhibitor). Furthermore, the proliferating cell nuclear antigen labeling index (PCNA-LI) of granulosa cells displayed similar changes with the number of cells. These results indicated that PGE1 promoted the proliferation of granulosa cells from SYF and was also involved in mediating FSH-stimulated intracellular PKA signal transduction.     

Neuregulin-1 enhances depolarization-induced GABA release

Neuregulin-1 (NRG1), a regulator of neural development, has been shown to regulate neurotransmission at excitatory synapses. Although ErbB4, a key NRG1 receptor, is expressed in glutamic acid decarboxylase (GAD)-positive neurons, little is known about its role in GABAergic transmission. We show that ErbB4 is localized at GABAergic terminals of the prefrontal cortex. Our data indicate a role of NRG1, both endogenous and exogenous, in regulation of GABAergic transmission. This effect was blocked by inhibition or mutation of ErbB4, suggesting the involvement of ErbB4. Together, these results indicate that NRG1 regulates GABAergic transmission via presynaptic ErbB4 receptors, identifying a novel function of NRG1. Because both NRG1 and ErbB4 have emerged as susceptibility genes of schizophrenia, these observations may suggest a mechanism for abnormal GABAergic neurotransmission in this disorder.     

In vivo performance of a dual genetic marker, manA-gfp, in transgenic bentgrass.

A dual-marker combination, manA-gfp, comprising 2 independent expression cassettes of genes encoding an Escherichia coli phosphomannose isomerase (PMI) and a synthetic green fluorescent protein (GFP), was incorporated into the binary vector pPZP201. Agrobacterium tumefaciens-mediated transfer was used to introduce the manA-gfp into the mature-seed derived calli of Agrostis stoloifera L. 'Crenshaw'. The putative transgenic bentgrass calli were screened in Murashige and Skoog medium containing 15 g mannose/L, in conjunction with a visual examination of the GFP expression with a fluorescence stereomicroscope. Calli with GFP fluorescence grew well on the mannose selection media. A total of 24 transgenic plants derived from a single piece of callus lobe were studied for the genomic integration, expression, and function of the transgene. Genomic integration of the dual markers manA and gfp was confirmed by Southern blotting analysis, and the expression of manA also was validated by using PMI-specific antiserum. The inheritance and expression of the dual marker, manA-gfp, was demonstrated in the T1 generation. This study on the environmentally friendly markers further documented the feasibility of using alternative selection methods without using herbicide- or antibiotic-resistance markers.     

Copper binding properties of a tau peptide associated with Alzheimer's disease studied by CD, NMR, and MALDI-TOF MS

We have previously reported the copper binding properties of R3 peptide (residues 318-335: VTSKCGSLGNIHHKPGGG, according to the longest tau protein) derived from the third repeat microtubule-binding domain of water-soluble tau protein. In this work, we have investigated copper binding properties of R2 peptide (residues 287-304: VQSKCGSKDNIKHVPGGG) derived from the second repeat region of tau protein. Similar to R3 peptide, R2 peptide also plays an important role in the formation of neurofibrillary tangles (NFTs) which is one of the two main biological characteristics of Alzheimer's disease (AD). Based on the copper binding properties of R2 peptide, the possible influences of the binding on the formation of NFTs were investigated. Results from circular dichroism (CD) spectra, nuclear magnetic resonance (NMR) spectroscopy, and matrix assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) suggest that the binding is pH-dependent and stoichiometry-determined. In addition, these results also reveal that R2 peptide adopts a monomeric alpha-helical structure in aqueous solutions at physiological pH after the addition of 1 mol equiv. of Cu2+. Since alpha-helix structure is responsible for the formation of paired helical filaments (PHFs) which aggregate into NFTs, it is hypothesized that Cu2+ induces R2 peptide to self-assemble into a PHFs-like structure. Hence, it is postulated that Cu2+ plays an important role in the aggregation of R2 peptide and tau protein and that copper binding to R2 peptide may be another possible involvement in AD.     

Alfalfa (Medicago sativa L.)/Maize (Zea mays L.) Intercropping Provides a Feasible Way to Improve Yield and Economic Incomes in Farming and Pastoral Areas of Northeast China

Given the growing challenges to food and eco-environmental security as well as sustainable development of animal husbandry in the farming and pastoral areas of northeast China, it is crucial to identify advantageous intercropping modes and some constraints limiting its popularization. In order to assess the performance of various intercropping modes of maize and alfalfa, a field experiment was conducted in a completely randomized block design with five treatments: maize monoculture in even rows, maize monoculture in alternating wide and narrow rows, alfalfa monoculture, maize intercropped with one row of alfalfa in wide rows and maize intercropped with two rows of alfalfa in wide rows. Results demonstrate that maize monoculture in alternating wide and narrow rows performed best for light transmission, grain yield and output value, compared to in even rows. When intercropped, maize intercropped with one row of alfalfa in wide rows was identified as the optimal strategy and the largely complementary ecological niches of alfalfa and maize were shown to account for the intercropping advantages, optimizing resource utilization and improving yield and economic incomes. These findings suggest that alfalfa/maize intercropping has obvious advantages over monoculture and is applicable to the farming and pastoral areas of northeast China.