Effect of static magnetic fields on the growth,photosynthesis and ultrastructure of Chlorella kessleri microalgae

Microalgal biotechnology could generate substantial amounts of biofuels with minimal environmental impact if the economics can be improved by increasing the rate of biomass production. Chlorella kessleri was grown in a small‐scale raceway pond and in flask cultures with the entire volume, 1% (v/v) at any instant, periodically exposed to static magnetic fields to demonstrate increased biomass production and investigate physiological changes, respectively. The growth rate in flasks was maximal at a field strength of 10 mT, increasing from 0.39 ± 0.06 per day for the control to 0.88 ± 0.06 per day. In the raceway pond the 10 mT field increased the growth rate from 0.24 ± 0.03 to 0.45 ± 0.05 per day, final biomass from 0.88 ± 0.11 to 1.56 ± 0.18 g/L per day, and maximum biomass production from 0.11 ± 0.02 to 0.38 ± 0.04 g/L per day. Increased pigment, protein, Ca, and Zn content made the biomass produced with magnetic stimulation nutritionally superior. An increase in oxidative stress was measured indirectly as a decrease in antioxidant capacity from 26 ± 2 to 17 ± 1 µmol antioxidant/g biomass. Net photosynthetic capacity (NPC) and respiratory rate were increased by factors of 2.1 and 3.1, respectively. Loss of NPC enhancement after the removal of magnetic field fit a first‐order model well (R² = 0.99) with a half‐life of 3.3 days. Transmission electron microscopy showed enlarged chloroplasts and decreased thylakoid order with 10 mT treatment. By increasing daily biomass production about fourfold, 10 mT magnetic field exposure could make algal oil cost competitive with other biodiesel feedstocks. Bioelectromagnetics 33:298–308, 2012. © 2011 Wiley Periodicals, Inc.     

Plasma proteome analysis of cervical intraepithelial neoplasia and cervical squamous cell carcinoma

Although cervical cancer is preventable with early detection, it remains the second most common malignancy among women. An understanding of how proteins change in their expression during a particular diseased state such as cervical cancer will contribute to an understanding of how the disease develops and progresses. Potentially, it may also lead to the ability to predict the occurrence of the disease. With this in mind, we aimed to identify differentially expressed proteins in the plasma of cervical cancer patients. Plasma from control, cervical intraepithelial neoplasia (CIN) grade 3 and squamous cell carcinoma (SCC) stage IV subjects was resolved by two-dimensional gel electrophoresis and the resulting proteome profiles compared. Differentially expressed protein spots were then identified by mass spectrometry. Eighteen proteins were found to be differentially expressed in the plasma of CIN 3 and SCC stage IV samples when compared with that of controls. Competitive ELISA further validated the expression of cytokeratin 19 and tetranectin. Functional analyses of these differentially expressed proteins will provide further insight into their potential role(s) in cervical cancer-specific monitoring and therapeutics.     

Plant nitrogen dynamics and nitrogen-use strategies under altered nitrogen seasonality and competition

BACKGROUND AND AIMS: Numerous studies have examined the effects of climatic factors on the distribution of C(3) and C(4) grasses in various regions throughout the world, but the role of seasonal fluctuations in temperature, precipitation and soil N availability in regulating growth and competition of these two functional types is still not well understood. This report is about the effects of seasonality of soil N availability and competition on plant N dynamics and N-use strategies of one C(3) (Leymus chinensis) and one C(4) (Chloris virgata) grass species. METHODS: Leymus chinensis and C. virgata, two grass species native to the temperate steppe in northern China, were planted in a monoculture and a mixture under three different N seasonal availabilities: an average model (AM) with N evenly distributed over the growing season; a one-peak model (OM) with more N in summer than in spring and autumn; and a two-peak model (TM) with more N in spring and autumn than in summer. KEY RESULTS: The results showed that the altered N seasonality changed plant N concentration, with the highest value of L. chinensis under the OM treatment and C. virgata under the TM treatment, respectively. N seasonality also affected plant N content, N productivity and N-resorption efficiency and proficiency in both the C(3) and C(4) species. Interspecific competition influenced N-use and resorption efficiency in both the C(3) and C(4) species, with higher N-use and resorption efficiency in the mixture than in monoculture. The C(4) grass had higher N-use efficiency than the C(3) grass due to its higher N productivity, irrespective of the N treatment or competition. CONCLUSIONS: The observations suggest that N-use strategies in the C(3) and C(4) species used in the study were closely related to seasonal dynamics of N supply and competition. N seasonality might be involved in the growth and temporal niche separation between C(3) and C(4) species observed in the natural ecosystems.     

Production of Transgenic Rice Homozygous Lines with Enhanced Resistance to the Rice Brown Planthopper

Mature seed‐derived callus from an elite Chinese japonica rice (Oryza sativa L.) cv. Eyi 105 was cotransformed with two plasmids, pWRG1515 and pRSSGNA1,containing the selectable marker hygromycin phosphotransferase gene (hpt), the reporter β‐glucuronidase gene (gusA) and the snow‐drop (Galanthus nivalis) lectin gene (gna) via particle bombardment. After two rounds of selection on hygromycin‐containing medium, resistant callus was transferred to hygromycin‐containing regeneration medium for plant regeneration. Twenty‐six independent transgenic rice plants were regenerated from 152 bombarded calli with a transformation frequency of 17%. Seventy‐three percent of transgenic plants contained all three genes, which was revealed by PCR/Southern blot analysis. Thirteen out of 19 transgenic plants containing the gna gene expressed GNA (68%) at various levels with the highest expression being approximately 0.5% of total soluble protein. Genetic analysis confirmed Mendelian segregation of transgenes in progeny. From R2 generations with their R1 parentplants showing 3:1 Mendelian segregation patterns, we identified three independent homozygous lines containing and expressing all three transgenes.Insect bioassay and feeding tests showed that these homozygous lines had significant inhibition to the rice brown planthopper (Nilaparvata lugens, BPH) by decreasing BPH survival and overall fecundity, retarding BPH development and reducing BPH feeding.This is the first report that homozygous transgenic rice lines expressing GNA, developed by genetic transformation and through genetic analysis‐based selection, conferred enhanced resistance to BPH, one of the most damaging insect pests in rice.     

Rab39, a novel Golgi-associated Rab GTPase from human dendritic cells involved in cellular endocytosis

Rab GTPases are Ras-like small molecular weight GTP binding proteins that are involved in various steps along the exocytic and endocytic pathways. Here we report that Rab39, a novel Rab protein, is a Golgi-associated protein involved in endocytosis of HeLa cells. Full-length cDNA of Rab39 contains 1251bp with an open reading frame (ORF) of 636bp, which is predicted to encode a 211 aa protein. By blast analysis of Rab39 cDNA and protein sequence with homologues, we find that Rab39 may be a short variant of Rab34. Rab39 contains conserved motifs involved in phosphate/guanosine binding and a microbody C-terminal targeting signal. RT-PCR analysis indicates that Rab39 is mainly detected in epithelial cell lines, and Northern blot analysis shows that Rab39 is expressed ubiquitously in human tissues. By using FITC-BSA as an endocytic tracer, we show that Rab39 can facilitate endocytosis in HeLa cells when expressed either transiently or stably. Confocal microscopy examination of Rab39 subcellular localization suggests that Rab39 is associated with Golgi-associated organelles. Our findings demonstrate that Rab39 is a novel Rab GTPase involved in cellular endocytosis.