Ecology detection of moderate thermophilic enrichment at Lau Basin hydrothermal vents

Culturable thermophilic microorganisms were enriched from samples collected from Lau Basin hydrothermal vents in artificial seawater medium at 45 ℃ and pH 7.0. Microbial diversities of the enriched communities were defined by performing a restriction fragment length polymorphism （RFLP） analysis of 16S rRNA gene sequences with enzymes MspI and Hin6 I. A total of 14 phylotypes have been detected by the RFLP patterns identified for 16S rRNA clone libraries of the enrichment. Analysis of sequences showed that at least four bacterial divisions presented in the clones libraries. The phyla Proteobacteria and Firmicutes were the most dominant groups. The majority of the sequences included in this analysis affiliated with Gamma Proteobacteria （71%） and Bacillus （23%）. Scanning electron micrographs revealed that there were abundant rod and coceoidal forms encased in sulphur and sodium chloride precipitate. These results revealed that there were a diversity of moderate thermophilic bacterial populations thrived in Lau Basin hydrothermal vents that were previously not detected by either molecular retrieval or strain purification techniques.

Allelopathic interactions between Prorocentrum micans and Skeletonema costatum or Karenia mikimotoi in laboratory cultures

Algal allelopathy is an ecological/physiological phenomenon that has focused attention on the interactions among algae and the production of algal toxins. We investigated the allelopathic interactions between the dinoflagellate genus Prorocentrum micans and diatom genus Skeletonema costatum and between P. micans and dinoflagellate genus Karenia mikimotoi using bi-algal cultures. Because the effects were species-specific and size-dependent, we evaluated the effect of different initial densities. At low densities of P. mieans and high densities of S. costatum inoculated into the same medium, the growth of R rnieans was weakly restrained, whereas the growth of S. costatum was significantly suppressed. S. costatum and K. mikimotoi were strongly inhibited by P. micans, in both the bi-algal cultures and enriched filtrates. Direct cell-to-cell contact was not necessary to gain a competitive advantage, thus, our results suggest that P. micans inhibited the growth of S. costatum and K. mikimotoi by the release of allelochemical（s）. Last, a mathematical model was used to simulate growth and interactions between P. micans and S. eostatum and between P. micans and K. mikimotoi in bi-algal cultures.

Applying Literature to ELT

Literature is no longer a frightening word to English language learner. Interactive teaching methods and attractive activities can help motivating Chinese university English learners. This essay will first elaborate the reasons to use literature in ELT (English Language Teaching) class and how to apply literature to ELT class.

Delignification of disposable wooden chopsticks waste for fermentative hydrogen production by an enriched culture from a hot spring

Hydrogen （H2） production from lignocellulosic materials may be enhanced by removing lignin and increasing the porosity of the material prior to enzymatic hydrolysis. Alkaline pretreatment conditions, used to delignify disposable wooden chopsticks （DWC） waste, were investigated. The effects of NaOH concentration, temperature and retention time were examined and it was found that retention time had no effect on lignin removal or carbohydrate released in enzymatic hydrolysate. The highest percentage of lignin removal （41%） was obtained with 2% NaOH at 100℃, correlated with the highest carbohydrate released （67 mg/gpretreated DWC） in the hydrolysate. An enriched culture from a hot spring was used as inoculum for fermentative H2 production, and its optimum initial pH and temperature were determined to be 7.0 and 50℃, respectively. Furthermore, enzymatic hydrolysate from pretreated DWC was successfully demonstrated as a substrate for fermentative H2 production by the enriched culture. The maximum H2 yield and production rate were achieved at 195 mL H2/g total sugarsconsumed and 1 16 mL Hz/（L.day）, respectively.

Diversity and Characterization of Potential H_2-Dependent Fe(Ⅲ)-Reducing Bacteria in Paddy Soils

Microbial ferric iron reduction, with organic carbon or hydrogen as the electron donor, is one of the most important biogeochemical processes in anoxic paddy soils; however, the diversity and community structure of hydrogen-dependent dissimilatory iron-reducers remain unknown. Potential H2-dependent Fe（III）-reducing bacteria in paddy soils were explored using enrichment cultures with ferrihydrite or goethite as the electron acceptor and hydrogen as the electron donor. Terminal restriction fragment length polymorphism （T-RFLP） analysis and cloning/sequencing were conducted to reveal bacterial community structure. Results showed that Geobacter and Clost^dium were the dominant bacteria in the enrichment cultures. Fe（III） oxide mineral phases showed a strong effect on the community structure; Geobaeter and Clostridium were dominant in the ferrihydrite treatment, while Glostridium spp. were dominant in the goethite treatment. These suggested that H2-dependent Fe（lII）-redueing bacteria might be widely distributed in paddy soils and that besides Geobacter, Clostmdium spp. might also be an important group of H2-dependent Fe（III）-reducing microorganisms.