Diversity of methanogenic archaea in a mangrove sediment and isolation of a new Methanococcoides strain

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Identification of the type ii cytochrome c maturation pathway in anammox bacteria by comparative genomics

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Rhizobium lipo-chitooligosaccharide signaling triggers accumulation of cytokinins in Medicago truncatula roots

Legume rhizobium symbiosis is initiated upon perception of bacterial secreted lipo-chitooligosaccharides (LCOs). Perception of these signals by the plant initiates a signaling cascade that leads to nodule formation. Several studies have implicated a function for cytokinin in this process. However, whether cytokinin accumulation and subsequent signaling are an integral part of rhizobium LCO signaling remains elusive. Here, we show that cytokinin signaling is required for the majority of transcriptional changes induced by rhizobium LCOs. In addition, we demonstrate that several cytokinins accumulate in the root susceptible zone 3 h after rhizobium LCO application, including the biologically most active cytokinins, trans-zeatin and isopentenyl adenine. These responses are dependent on calcium- and calmodulin-dependent protein kinase (CCaMK), a key protein in rhizobial LCO-induced signaling. Analysis of the ethylene-insensitive Mtein2/Mtsickle mutant showed that LCO-induced cytokinin accumulation is negatively regulated by ethylene. Together with transcriptional induction of ethylene biosynthesis genes, it suggests a feedback loop negatively regulating LCO signaling and subsequent cytokinin accumulation. We argue that cytokinin accumulation is a key step in the pathway leading to nodule organogenesis and that this is tightly controlled by feedback loops

Expanding the verrucomicrobial methanotrophic world: Description of three novel species of methylacidimicrobium gen. Nov

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A novel marine nitrite-oxidizing Nitrospira species from Dutch coastal North Sea Water

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Biochemistry and molecular biology of anammox bacteria

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The anaerobic fungus Neocallimastix sp. strain L2:Growth and production of (Hemi)cellulolytic enzymes on a range of carbohydrate substrates

The anaerobic fungus Neocallimastix sp. strain L2, isolated from the feces of a Ilama, was tested for growth on a range of soluble and insoluble carbohydrate substrates. The fungus was able to ferment glucose, cellobiose, fructose, lactose, maltose, sucrose, soluble starch, inulin, filter paper cellulose, and Avicel. No growth was observed on arabinose, galactose, mannose, ribose, xylose, sorbitol, pectin, xylan, glycerol, citrate, soya, and wheat bran. The fermentation products after growth were hydrogen, formate, acetate, ethanol, and lactate. The fermentation pattern was dependent on the carbon source. In general, higher hydrogen production resulted in decreased formation of lactate and ethanol. Recovery of the fermented carbon in products at the end of growth ranged from 50% to 80%. (Hemi)cellulolytic enzyme activities were affected by the carbon source. Highest activities were found in filtrates from cultures grown on cellulose. Growing the fungus on inulin and lactose yielded the lowest cellulolytic activities. Highest specific activities for avicelase, endoglucanase, mu-glucosidase, and xylanase were obtained with Avicel as the substrate for growth (0.29, 5.9, 0.57, and 13 IU . mg(-1) protein, respectively). Endoglucanase activity banding patterns after SDS-PAGE were very similar for all substrates. Minor differences indicated that enzyme activities may in part be the result of secretion of different sets of isoenzymes