Methanogenesis from the biomass in the anoxic biogas reactors is catalyzed by syntrophic cooperation between anaerobic bacteria, syntrophic acetogenic bacteria and methanogenic archaea. Understanding of microbial community composition within the biogas reactors may improve the methane production from biomass fermentation. In this study, methanogenic archaea diverity of a biogas reactor supplied with swine feces as mono-substrate under mesophilic conditions was investigated. Community composition was determined by analysis of methyl coenzyme reductase subunit A gene (mcrA) clone library consisting of 123 clones. Statistical analysis of mcrA library indicated that all major groups of methanogens from our biogas reactor were detected. In the library, 57.7% clones were affiliated to Methanobacteriales, 34.2% to Methanomicrobiales, 2.4% to Methanosarcinales and about 5.7% clones belonged to unclassified euryarchaeota. Over 90% of the methanogenic archaea from our biogas reactor were postulated to be hydrogenotrophic methanogens. Comparing with other previous studies reporting that hydrogenotrophic methanogens are dominant species in the biogas plants, this study firstly reported that Methanobacteriales instead of Methanomicrobiales are the most predominant methanogenic archaea in the biogas reactor fed with swine feces as sole substrate.

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Chloroplasts are of prokaryotic origin with a double-membrane envelope separating plastid metabolism from the cytosol. Envelope membrane proteins integrate chloroplasts with the cell, but envelope biogenesis mechanisms remain elusive. We show that maize defective kernel5 (dek5) is critical for envelope biogenesis. Amyloplasts and chloroplasts are larger and reduced in number in dek5 with multiple ultrastructural defects. The DEK5 protein is homologous to rice SSG4, Arabidopsis thaliana EMB2410/TIC236, and Escherichia coli tamB. TamB functions in bacterial outer membrane biogenesis. DEK5 is localized to the envelope with a topology analogous to TamB. Increased levels of soluble sugars in dek5 developing endosperm and elevated osmotic pressure in mutant leaf cells suggest defective intracellular solute transport. Proteomics and antibody-based analyses show dek5 reduces levels of Toc75 and chloroplast envelope transporters. Moreover, dek5 chloroplasts reduce inorganic phosphate uptake with at least an 80% reduction relative to normal chloroplasts. These data suggest that DEK5 functions in plastid envelope biogenesis to enable transport of metabolites and proteins.

Positional cloning in maize (Zea mays) requires development of markers in the region of interest. We found that primers designed to amplify annotated insertion–deletion polymorphisms of seven base pairs or greater between B73 and Mo17 produce polymorphic markers at a 97% frequency with 49% of the products showing co-dominant fragment length polymorphisms. When the same polymorphisms are used to develop markers for B73 and W22 or Mo17 and W22 mapping populations, 22% and 31% of markers are co-dominant, respectively. There are 38,223 Indel polymorphisms that can be converted to markers providing high-density coverage throughout the maize genome. This strategy significantly increases the efficiency of marker development for fine-mapping in maize.