Effects of pH and ORP on microbial ecology and kinetics for hydrogen production in continuously dark fermentation

The microbial structure and kinetic characteristics of the hydrogen producing strains in two fermentative continuous stirred-tank reactors (CSTRs) were studied by controlling pH and oxidation and reduction potential (ORP). The fluorescence in situ hybridization (FISH) tests were conducted to investigate the fermentative performance of Clostridium histolyticum (C. histolyticum), Clostridium lituseburense (C. lituseburense) and Enterobacteriaceae. The experimental results showed that in ethanol-type reactor 1#, the relative abundance of the strains was 48%, 30% and 22%. Comparatively, the relative abundance in butyric acid-type reactor 2# was 24%, 55% and 19% with butyric acids and hydrogen as the main products. The kinetic results indicated that the hydrogen yield coefficients Y_P/X in both reactors were 8.357 and 5.951 l-H₂/g, while the coefficients of the cellular yield were 0.0268 and 0.0350 g-Cell/g, respectively. At the same biomass, the hydrogen yield in ethanol-type reactors was more than that in butyric acid reactors. However, the cellular synthesis rate in ethanol-type reactors was low when the same carbon source was used.     

四种番荔枝科植物花粉形态

利用扫描和透射电子显微镜,观察了番荔枝科(Annonaceae)4属4种植物的花粉形态与结构.刺果番荔枝(Annona muricata)和金钩花(Pseuduvaria trimera)为四合花粉,有四角形、偏菱形、T-型、十字形和四面体形.前者花粉表面具小穿孔,后者为皱波状纹饰.蕉木(Oncodostigma hainanense)和那大紫玉盘(Uvaria macclurei)为单花粉,前者表面为皱波状纹饰,后者为粗褶皱状纹饰.透射电子显微镜下,蕉木和那大紫玉盘覆盖层较厚、连续.蕉木覆盖下层较薄,偶尔可见颗粒状物质或不规则小柱,为过渡型覆盖下层;那大紫玉盘覆盖下层颗粒状.基层分为内外两层,外层较厚,平或呈波浪状,内层具有2～4片层结构.在不同属或同属不同种之间,花粉特征差异较大,多样性非常丰富.金钩花具有四合花粉、覆盖下层小柱状等进化特征,同时又具有花粉粒小、覆盖层无穿孔等较原始特征.     

RPAP3 interacts with Reptin to regulate UV‐induced phosphorylation of H2AX and DNA damage

We have previously reported that Monad, a novel WD40 repeat protein, potentiates apoptosis induced by tumor necrosis factor‐α and cycloheximide. By affinity purification and mass spectrometry, RNA polymerase II‐associated protein 3 (RPAP3) was identified as a Monad binding protein and may function with Monad as a novel modulator of apoptosis pathways. Here we report that Reptin, a highly conserved AAA + ATPase that is part of various chromatin‐remodeling complexes, is also involved in the association of RPAP3 by immunoprecipitation and confocal microscopic analysis. Overexpression of RPAP3 induced HEK293 cells to death after UV‐irradiation. Loss of RPAP3 by RNAi improved HeLa cell survival after UV‐induced DNA damage and attenuated the phosphorylation of H2AX. Depletion of Reptin reduced cell survival and facilitated the phosphorylation on H2AX. These results suggest that RPAP3 modulates UV‐induced DNA damage by regulating H2AX phosphorylation. J. Cell. Biochem. 106: 920–928, 2009. © 2009 Wiley‐Liss, Inc.     

Ontogenesis of monad pollen inPterostylis plumosa (Orchidaceae,Neottioideae)

Pterostylis plumosa (Neottioideae) is an orchid with monosulcate monad pollen. Tetrads may be isobilateral, decussate, tetrahedral, rhomboid or T-shaped, but all pollen grains have a similar shape. Those belonging to the same tetrads are contiguous from microspore release to opening of the anther, with the furrow oriented inwards. Sporophytic proteins are present outside the furrow. The tapetum is of the parietal type without orbicles. The increase in pollen grain size between meiosis and maturity is only three-fold. The generative cell is spherical when the pollen is mature. These features are discussed in relation to the primitive nature of the species.