The Protective Effect of Selenium on Bovine Mammary Epithelial Cell Injury Caused by Depression of Thioredoxin Reductase

To elucidate the effect of selenium (Se) on antioxidant function of mammary glands in dairy cows and the underlying mechanism, an experiment was conducted using a single-factor completely randomized design study. Bovine mammary epithelial cells (BMECs) were randomly divided into four groups: control, Se treatment, 2,4-dinitrochlorobenzene (DNCB) inhibition, and Se prevention. Treatment of BMECs with Se was found to significantly reverse decreased cell proliferation and the expression of thioredoxin reductase (TrxR) after DNCB exposure. DNCB-induced activation of apoptosis signaling kinase-1 (ASK-1), which activates the mitogen-activated protein kinase (MAPK) pathway, was reduced in BMECs treated with Se. Additionally, our results indicated that Se treatment resulted in lower intracellular accumulation of arachidonic acid (ARA) and 15-hydroperoxyeicosatetraenoic acid (15-HPETE) due to suppressed expression of cytosolic phospholipase A₂ (cPLA₂) regulated by p38MAPK and c-Jun N-terminal kinase (JNK) in DNCB-stimulated BMECs. Taken together, these findings suggest that Se treatment improved the antioxidant function of dairy cow mammary glands and protected cells from oxidative damage primarily by increasing the activity of TrxR, inhibiting the activation of the MAPK signaling pathway, and thus decreasing the content of ARA and its related metabolites.     

Gain in 1q is a common abnormality in phyllodes tumours of the breast.

We studied DNA copy number changes by CGH and allelic imbalance (AI) on 3p by LOH analysis on 22 phyllodes tumours (PT) of the breast in order to gain insight into the genetic basis of tumour progression in PT. Copy number changes were observed in 14 cases (63%). Gain in 1q with 1q21-23 as the minimal overlapping area was seen in 12 cases (55%). The gain was observed both in benign and malignant tumours. Our study did not reveal any DNA copy number changes or allelic loss on 3p. The results suggest that DNA copy number changes are not associated with the histological grade or clinical behaviour of PT and the chromosomal changes on 3p appear to be rare. Colour figure can be viewed on http://www.esacp.org/acp/2003/25-2/jee.htm     

The ubiquinone-binding site in NADH:ubiquinone oxidoreductase from Escherichia coli

An azido-ubiquinone derivative, 3-azido-2-methyl-5-methoxy[3H]-6-decyl-1,4-benzoquinone ([3H]azido-Q), was used to study the ubiquinone/protein interaction and to identify the ubiquinone-binding site in Escherichia coli NADH:ubiquinone oxidoreductase (complex I). The purified complex I showed no loss of activity after incubation with a 20-fold molar excess of [3H]azido-Q in the dark. Illumination of the incubated sample with long wavelength UV light for 10 min at 0 degrees C caused a 40% decrease of NADH:ubiquinone oxidoreductase activity. SDS-PAGE of the complex labeled with [3H]azido-Q followed by analysis of the radioactivity distribution among the subunits revealed that subunit NuoM was heavily labeled, suggesting that this protein houses the Q-binding site. When the [3H]azido-Q-labeled NuoM was purified from the labeled reductase by means of preparative SDS-PAGE, a 3-azido-2-methyl-5-methoxy-6-decyl-1,4-benzoquinone-linked peptide, with a retention time of 41.4 min, was obtained by high performance liquid chromatography of the protease K digest of the labeled subunit. This peptide had a partial NH2-terminal amino acid sequence of NH2-VMLIAILALV-, which corresponds to amino acid residues 184-193 of NuoM. The secondary structure prediction of NuoM using the Toppred hydropathy analysis showed that the Q-binding peptide overlaps with a proposed Q-binding motif located in the middle of the transmembrane helix 5 toward the cytoplasmic side of the membrane. Using the PHDhtm hydropathy plot, the labeled peptide is located in the transmembrane helix 4 toward the periplasmic side of the membrane.     

Genetic transformation and genes for resistance to abiotic and biotic stresses in Citrus and its related genera

Citrus is the most important tree fruit crop in the world. However, citrus production is affected by both biotic and abiotic stresses, including drought, extreme temperature, salinity, citrus canker, citrus tristeza virus, and Huanglongbing (or citrus greening), among others. These stresses can severely influence growth and development of both rootstocks and/or scions of citrus trees, thus reducing both fruit production and fruit quality. Modern advances in the tools of plant biotechnology and advances in genomics play important roles in understanding how citrus crops can cope with diseases and adverse environmental conditions. Within the last decades, much progress has been made in identifying and cloning of genes involved in resistance to biotic and abiotic stresses as well in genetic transformation of Citrus and its related genera, such as Poncirus trifoliata and Fortunella spp. In this review, we will provide information on advances and insights on genetic transformation protocols as well as availability of characterized genes involved in resistance to both abiotic and biotic stresses. This will be followed with a discussion on perspectives of future developments in this field.     

Salidroside Inhibits Reactive Astrogliosis and Glial Scar Formation in Late Cerebral Ischemia via the Akt/GSK-3β Pathway

Neurochemical Research - Cerebral ischemia leads to reactive astrogliosis and glial scar formation. Glial scarring can impede functional restoration during the recovery phase of stroke. Salidroside...     

Identification of three protein disulfide isomerase members from Haemaphysalis longicornis tick

Three genes encoding putative protein disulfide isomerase (PDI) were isolated from the Haemaphysalis longicornis EST database and designed as HlPDI-1, HlPDI-2, and HlPDI-3. All three PDI genes contain two typical PDI active sites CXXC and encode putative 435, 499, and 488 amino acids, respectively. The recombinant proteins expressed in Escherichia coli all show PDI activities, and the activities were inhibited by a PDI-specific inhibitor, zinc bacitracin. Western blot analysis and real-time PCR revealed that three HlPDIs were present in all the developmental stages of the tick as well as in the midgut, salivary glands, ovary, hemolymph, and fatbody of adult female ticks, but the three genes were expressed at the highest level in the egg stage. HlPDI-1 is expressed primarily in the ovary and secondarily in the salivary glands. HlPDI-2 and HlPDI-3 are expressed primarily in the salivary gland, suggesting that the PDI genes are important for tick biology, especially for egg development, and that they play distinct roles in different tissues. Blood feeding induced significantly increased expression of HlPDI-1 and HlPDI-3 in both partially fed nymphs and adults. Babesia gibsoni-infected larval ticks expressed HlPDI-1 and HlPDI-3 2.0 and 4.0 times higher than uninfected normal larval ticks, respectively. The results indicate that HlPDI-1 and HlPDI-3 might be involved in tick blood feeding and Babesia parasite infection in ticks.     

Ecotoxicity of soils contaminated with industrial and domestic wastewater in western shenyang,China

Soil samples were collected from 7 sites in the up-, mid-and down-reach along and nearby the wastewater irrigation channel, western Shenyang of China. The concentrations of selected pollutants (mineral oil, PAHs - polycycle aromatic hydrocarbons and Cd) were determined by UV spectrometer, HPLC and AAS (atomic adsorption spectrometer) spectrometer, respectively. Toxicity effects of soils were evaluated by seedling emergence test with root length of wheat as the end-point and by earthworms test with the mortality rate and inhibition rates of body weight as endpoints. Results showed accumulation of pollutants for most soils with concentration of 200.2 mg.kg⁻¹∼1600 mg.kg⁻¹ for mineral oil, 0.33 mg.kg⁻¹∼1.81 mg.kg⁻¹ for Cd and 900.16 mg.kg⁻¹ ∼ 2737.91 mg.kg⁻¹ for PAHs. The inhibition rates of root elongation were from −20% up to 40 %, and mortality rates of earthworms ranged from 0%∼40% from the exposure period of two weeks to eight weeks by sampling interval of two weeks, the inhibition rates of earthworm growth were from −19.36% to 34.53%, showing effects of stimulation at 2 weeks to an increasing effects of inhibition at 4, 6 and 8 weeks, respectively. Mortality rates correlated with the loss of body weight of earthworms.

This study indicated the potential risk of pollutants of environmental low content in soil by the determination of selected chemicals combined with toxicity indexes.

     

Effects of fertigation scheme on N uptake and N use efficiency in cotton

While fertigation can increase fertilizer use efficiency, there is an uncertainly as to whether the fertilizer should be introduced at the beginning of the irrigation or at the end, or introduced during irrigation. Our objective was to determine the effect of different fertigation schemes on nitrogen (N) uptake and N use efficiency (NUE) in cotton plants. A pot experiment was conducted under greenhouse conditions in year 2004 and 2005. According to the application timing of nitrogen (N) fertilizer solution and water (W) involved in an irrigation cycle, four nitrogen fertigation schemes [nitrogen applied at the beginning of the irrigation cycle (N–W), nitrogen applied at the end of the irrigation cycle (W–N), nitrogen applied in the middle of the irrigation cycle (W–N–W) and nitrogen applied throughout the irrigation cycle (N&W)] were employed in a completely randomized design with four replications. Cotton was grown in plastic containers with a volume of 84 l, which were filled with a clay loam soil and fertilized with 6.4 g of N per pot as unlabeled and ¹⁵N-labeled urea for 2004 and 2005, respectively. Plant total dry matter (DM) and N content in N–W was significantly higher than in N&W in both seasons, but these were not consistent for W–N and W–N–W treatments. In year 2005, a significantly higher nitrogen derived from fertilizer (NDFF) for the whole plant was found in W–N and N–W than that in W–N–W and N&W. Fertigation scheme had a consistent effect on total NUE: N–W had the highest NUE for the whole plant, but this was not significantly different from W–N. Treatments W–N and W–N–W had similar total NUE, and N&W had the lowest total NUE. After harvesting, the total residual fertilizer N in the soil was highest in W–N, lowest in N–W, but this was not significantly different from N&W and W–N–W treatments. Total residual NO₃–N in the soil in N&W and W–N treatments was 20.7 and 21.2% higher than that in N–W, respectively. The total ¹⁵N recovery was not statistically significant between the four fertigation schemes. In this study, the fertigation scheme N–W (nitrogen applied at the beginning of an irrigation cycle) increased DM accumulation, N uptake and NUE of cotton. This study indicates that Nitrogen application at the beginning of an irrigation cycle has an advantage on N uptake and NUE of cotton. Therefore, NUE could be enhanced by optimizing fertilization schemes with drip irrigation.