Archaea

各种支持载波用于在厌氧废水处理系统产甲烷古细菌的高密度保持性。虽然载体材料和微生物的物理化学性质影响产甲烷古细菌的附着，关于底层机制的细节仍然很差表征。我们应用七种类型的化学表面修改以碳毡，以澄清的粘附性能Methanothermobacter thermautotrophicus, a representative thermophilic hydrogenotrophic methanogen. The relationship between carrier surface properties and methanogen adhesion was evaluated.M. thermautotrophicusadhesion was significantly increased up to 2.6 times in comparison with control on carbon felts treated with NaOH, HCl, H₂SO₄, or Na₂HPO₄. Treated carbon felts showed a lower water contact angle, but no correlation between the carrier surface contact angle and methanogen adhesion was observed. On the other hand, at the surface of the carrier that showed improved adhesion of methanogens, the ratio of -COOH : -OH was 1 : 0.65. Such a ratio was not observed with treated carriers for which methanogen adhesion was not improved. Therefore, in the adhesion ofM. thermautotrophicus, the functional group abundance was important as well as physical surface properties such as the hydrophobicity. Hydrogenotrophic methanogens are involved in active methanation during the startup of anaerobic digestion. Additionally, these methanogenic archaea function as methanogenic cathode catalysts. Therefore, anaerobic digestion performance will greatly improve by controlling the adhesion of hydrogenotrophic methanogens such asM. thermautotrophicus.

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海草通过沉积海草纤维和释放从根部有机碳和氧定植涂改沉积物的物理化学性质。这种海草殖民引起的空间异质性如何影响古菌群落结构和数量尚不清楚。在这项研究中，我们调查古菌丰度，多样性和组合物中的两植被和相邻的裸露表面沉积物Zostera marinameadow. High-throughput sequencing of 16S rDNA showed thatWoesearchaeota,Bathyarchaeota, andThaumarchaeotawere the most abundant phyla across all samples, accounting for approximately 42%, 21%, and 17% of the total archaeal communities, respectively. In terms of relative abundance,WoesearchaeotaandBathyarchaeotawere not significantly different between these two niches; however, specific subclades (Woese-3, Woese-21, Bathy-6, Bathy-18) were significantly enriched in vegetated sediments ( ),whileThaumarchaeotawas favored in unvegetated sites ( ).The quantification of archaeal 16S rRNA genes showed that the absolute abundance of the whole archaeal community,Bathyarchaeota, and Woese-3, Woese-10, Woese-13, and Woese-21 was significantly more abundant in vegetated sediments than in bare sediments ( ).Our study expands the available knowledge of the distribution patterns and niche preferences of archaea in seagrass systems, especially for the different subclades ofWoesearchaeotaandBathyarchaeota，在这两个相对比例和绝对数量方面。

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The inoculum source plays a crucial role in the anaerobic treatment of wastewaters. Lipids are present in various wastewaters and have a high methanogenic potential, but their hydrolysis results in the production of long chain fatty acids (LCFAs) that are inhibitory to anaerobic microorganisms. Screening of inoculum for the anaerobic treatment of LCFA-containing wastewaters has been performed at mesophilic and thermophilic conditions. However, an evaluation of inocula for producing methane from LCFA-containing wastewater has not yet been conducted at low temperatures and needs to be undertaken. In this study, three inocula (one granular sludge and two municipal digester sludges) were assessed for methane production from LCFA-containing synthetic dairy wastewater (SDW) at low temperatures (10 and 20°C). A methane yield (based on mL-CH₄/g-COD_added) of 86-65% with acetate and 45-20% with SDW was achieved within 10 days using unacclimated granular sludge, whereas the municipal digester sludges produced methane only at 20°C but not at 10°C even after 200 days of incubation. The acetotrophic activity in the inoculum was found to be crucial for methane production from LCFA at low temperatures, highlighting the role ofMethanosaeta(acetoclastic archaea) at low temperatures. The presence of bacterial taxa from the familySyntrophaceae(Syntrophus和未培养的类群）在接种物被发现是产生甲烷从SDW在10℃很重要。这项研究表明acetotrophic活性和初始微生物群落特性通过高通量测序的扩增子的评价用于选择所述接种物在低温下从含脂质的废水产生甲烷（最多10℃）。

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微生物被很好地适用于它们的栖息地，而是将毒性代谢物或通过其它有机体分泌或化学的各个环境条件下形成的非生物性化合物部分地敏感。Thermoacidophiles由焦谷氨酸，即自发谷氨酸环化需氧嗜热条件下形成的内酰胺的挑战。众所周知的嗜热crenarchaeon的生长Saccharolobus叶菌(formerlySulfolobus solfataricus) is completely inhibited by pyroglutamate. In the present study, we investigated the effect of pyroglutamate on the growth ofS. solfataricus和密切相关的crenarchaeon嗜酸热硫化.与此相反S. solfataricus,S. acidocaldariuswas successfully cultivated with pyroglutamate as a sole carbon source. Bioinformatical analyses showed that both members of theSulfolobaceaehave at least one candidate for a 5-oxoprolinase, which catalyses the ATP-dependent conversion of pyroglutamate to glutamate. InS. solfataricus, we observed the intracellular accumulation of pyroglutamate and crude cell extract assays showed a less effective degradation of pyroglutamate. Apparently,S. acidocaldariusseems to be less versatile regarding carbohydrates and prefers peptidolytic growth compared toS. solfataricus. Concludingly,S. acidocaldariusexhibits a more efficient utilization of pyroglutamate and is not inhibited by this compound, making it a better candidate for applications with glutamate-containing media at high temperatures.

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Information on environmental conditions shaping archaeal communities thriving at the seafloor of the central Pacific Ocean is limited. The present study was conducted to investigate the diversity, composition, and function of both entire and potentially active archaeal communities within Pacific deep-sea sediments. For this purpose, sediment samples were taken along the 180° meridian of the central Pacific Ocean. Community composition and diversity were assessed by Illumina tag sequencing targeting archaeal 16S rRNA genes and transcripts. Archaeal communities were dominated by CandidatusNitrosopumilus(Thaumarchaeota) and other members of theNitrosopumilaceae(Thaumarchaeota), but higher relative abundances of the Marine Group II (Euryarchaeota) were observed in the active compared to the entire archaeal community. The composition of the entire and the active archaeal communities was strongly linked to primary production (chlorophyll content), explaining more than 40% of the variance. Furthermore, we found a strong correlation of the entire archaeal community composition to latitude and silicic acid content, while the active community was significantly correlated with primary production and ferric oxide content. We predicted functional profiles from 16S rRNA data to assess archaeal community functions. Latitude was significantly correlated with functional profiles of the entire community, whereas those of the active community were significantly correlated with nitrate and chlorophyll content. The results of the present study provide first insights into benthic archaeal communities in the Pacific Ocean and environmental conditions shaping their diversity, distribution, and function. Additionally, they might serve as a template for further studies investigating archaea colonizing deep-sea sediments.

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A system is described which permits the efficient synthesis of proteins体外at high temperature. It is based on the use of an unfractionated cell lysate (S30) fromSulfolobus solfataricuspreviously well characterized in our laboratory for translation of pretranscribed mRNAs, and now adapted to perform coupled transcription and translation. The essential element in this expression system is a strong promoter derived from theS. solfataricus16S/23S rRNA-encoding gene, from which specific mRNAs may be transcribed with high efficiency. The synthesis of two different proteins is reported, including theS. solfataricusDNA-alkylguanine-DNA-alkyl-transferase protein (SsOGT), which is shown to be successfully labeled with appropriate fluorescent substrates and visualized in cell extracts. The simplicity of the experimental procedure and specific activity of the proteins offer a number of possibilities for the study of structure-function relationships of proteins.

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