hemicellulose OR C007916 Dotaz Zobrazit nápovědu
Methods in enzymology ; Vol. 160
774 s. : il.
- Konspekt
- Biochemie. Molekulární biologie. Biofyzika
- NLK Obory
- biochemie
Evidence shows that bacteria contribute actively to the decomposition of cellulose and hemicellulose in forest soil; however, their role in this process is still unclear. Here we performed the screening and identification of bacteria showing potential cellulolytic activity from litter and organic soil of a temperate oak forest. The genomes of three cellulolytic isolates previously described as abundant in this ecosystem were sequenced and their proteomes were characterized during the growth on plant biomass and on microcrystalline cellulose. Pedobacter and Mucilaginibacter showed complex enzymatic systems containing highly diverse carbohydrate-active enzymes for the degradation of cellulose and hemicellulose, which were functionally redundant for endoglucanases, β-glucosidases, endoxylanases, β-xylosidases, mannosidases and carbohydrate-binding modules. Luteibacter did not express any glycosyl hydrolases traditionally recognized as cellulases. Instead, cellulose decomposition was likely performed by an expressed GH23 family protein containing a cellulose-binding domain. Interestingly, the presence of plant lignocellulose as well as crystalline cellulose both trigger the production of a wide set of hydrolytic proteins including cellulases, hemicellulases and other glycosyl hydrolases. Our findings highlight the extensive and unexplored structural diversity of enzymatic systems in cellulolytic soil bacteria and indicate the roles of multiple abundant bacterial taxa in the decomposition of cellulose and other plant polysaccharides.
- MeSH
- Bacteria chemie klasifikace izolace a purifikace metabolismus MeSH
- bakteriální proteiny analýza MeSH
- celulosa metabolismus MeSH
- dub (rod) růst a vývoj MeSH
- genom bakteriální MeSH
- hydrolýza MeSH
- lesy MeSH
- polysacharidy metabolismus MeSH
- proteom analýza MeSH
- půdní mikrobiologie * MeSH
- sekvenční analýza DNA MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Soybean (Glycine max L.) has been extensively cultivated in maize-soybean relay intercropping systems in southwest China. However, during the early co-growth period, soybean seedlings suffer from severe shading by maize resulting in lodging and significant yield reduction. The purpose of the present research was to investigate the reasons behind severe lodging and yield loss. Therefore, four different soybean genotypes (B3, B15, B23, and B24) having different agronomic characteristics were cultivated in intercropping and monocropping planting patterns. The results showed that under different planting patterns, the stem resistance varied among genotypes (P < 0.01). The lodging resistance index of B3, B15, B23, and B24 genotypes was 70.9%, 60.5%, 65.2%, and 57.4%, respectively, under intercropping, among which the B24 genotype was less affected by the shade environment as there was little decrease in the lodging resistance index of this genotype under intercropping. The lignin content of B23 and B24 was significantly higher than that of B3 and B15 under both planting patterns. Under intercropping, the hemicellulose content of B23 and B24 stems was significantly higher than that of B3 and B15. Compared to the monocropping, the content of mannose in the structural carbohydrate of soybean stems was decreased in all genotypes except B23, but the difference was not significant. The content of xylose in the structural carbohydrate of soybean stems was significantly higher than that in B3 and B15. Mannose content showed no significant difference among genotypes. The arabinose content of B24 was significantly higher than that of B3, B15, and B23. The effective pod number, seed number per plant, seed weight per plant and yield of soybean plants were significantly decreased under intercropping. Conclusively, manipulation of structural and nonstructural carbohydrate rich soybean genotypes in intercropping systems could alleviate the yield loss due to lodging.
- MeSH
- celulosa genetika metabolismus MeSH
- fyziologický stres genetika fyziologie MeSH
- genotyp MeSH
- Glycine max genetika metabolismus MeSH
- lignin genetika metabolismus MeSH
- monosacharidy genetika metabolismus MeSH
- polysacharidy genetika metabolismus MeSH
- sacharosa metabolismus MeSH
- stonky rostlin genetika fyziologie MeSH
- Publikační typ
- časopisecké články MeSH
Selective hydrolysis of the hemicellulose fraction of olive-pruning debris was attempted in order to achieve a maximum yield of fermentable D-xylose without degrading the cellulose fraction. To this end, hydrolysis with a dilute acid was conducted in a heterogeneous stirred tank reactor at mild temperature (70-90 °C) and sulfuric acid concentration (0.0-0.5 mol l-1) for 300 min. Temperature was the determining factor in sugar formation and fiber conversion. The highest hemicellulose and cellulose conversion at 90 °C were 92.9 and 16.0%, respectively. From 100 g of the raw material, 35.8 g of sugars were recovered. At this temperature, using 0.5 M H2SO4 for 4.5 h, D-glucose and D-xylose yields of 13.1 and 10.4%, respectively, were obtained.
Soil microorganisms are important mediators of carbon cycling in nature. Although cellulose- and hemicellulose-degrading bacteria have been isolated from Algerian ecosystems, the information on the composition of soil bacterial communities and thus the potential of their members to decompose plant residues is still limited. The objective of the present study was to describe and compare the bacterial community composition in Algerian soils (crop, forest, garden, and desert) and the activity of cellulose- and hemicellulose-degrading enzymes. Bacterial communities were characterized by high-throughput 16S amplicon sequencing followed by the in silico prediction of their functional potential. The highest lignocellulolytic activity was recorded in forest and garden soils whereas activities in the agricultural and desert soils were typically low. The bacterial phyla Proteobacteria (in particular classes α-proteobacteria, δ-proteobacteria, and γ-proteobacteria), Firmicutes, and Actinobacteria dominated in all soils. Forest and garden soils exhibited higher diversity than agricultural and desert soils. Endocellulase activity was elevated in forest and garden soils. In silico analysis predicted higher share of genes assigned to general metabolism in forest and garden soils compared with agricultural and arid soils, particularly in carbohydrate metabolism. The highest potential of lignocellulose decomposition was predicted for forest soils, which is in agreement with the highest activity of corresponding enzymes.
- MeSH
- Bacteria klasifikace enzymologie genetika izolace a purifikace MeSH
- bakteriální proteiny genetika metabolismus MeSH
- celulasa genetika metabolismus MeSH
- ekosystém MeSH
- fylogeneze MeSH
- glykosidhydrolasy genetika metabolismus MeSH
- lesy MeSH
- půda chemie MeSH
- půdní mikrobiologie * MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Alžírsko MeSH
Tall fescue (Festuca arundinacea Schreb) shows remarkable tolerance to lead (Pb), but the mechanisms involved in metal tolerance are not yet well understood. Here, tall fescue were firstly cultivated hydroponically with Pb2+ (0, 50, 200 and 1000 mg/L) for 14 days. The results showed that remodeling of root architecture plays important roles in tolerance of tall fescue to Pb2+ stress. Increased cell wall (CW) components contribute to restrict high amount of Pb2+ in roots. Additionally, the uronic acid contents of pectin, hemicellulose 1 (HC1) and hemicellulose 2 (HC2) increased under Pb2+ stress. We further observed that tall fescue cultivated with H2O2 showed similar remodeling of root architecture as Pb2+ treatment. Furthermore, pectin, HC1 and HC2 fractions were sequentially extracted from 0 and 10 mM H2O2 treated roots, and Pb2+ adsorption capacity and contents of carboxyl groups of pectin and HC2 fractions were steadily increased under H2O2 treatment in vitro. Our results suggest that degrees of esterification of pectin and HC2 are regulated by H2O2. High amount of low-esterified pectin and HC2 offer more carboxyl groups, provide more Pb2+ binding sites, and restrict more Pb2+ in the CW, which may enhance tolerance of tall fescue to Pb2+ stress.
- MeSH
- buněčná stěna účinky léků metabolismus MeSH
- esterifikace MeSH
- Festuca účinky léků metabolismus MeSH
- kořeny rostlin účinky léků metabolismus MeSH
- látky znečišťující půdu metabolismus toxicita MeSH
- olovo metabolismus toxicita MeSH
- oxidační stres účinky léků MeSH
- polysacharidy chemie metabolismus MeSH
- reaktivní formy kyslíku metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Conclusions from narrative qualitative reviews on differences in total tract digestibilities between goats and sheep did not account for variability among studies. Therefore meta-analytic techniques were used to describe the magnitude of these differences with numerical values. A unitless effect size (Hedges' g) was applied within studies to measure differences in digestibilities of dry matter (DM; 104 comparisons), organic matter (OM; 93 comparisons), crude protein (CP; 85 comparisons), neutral detergent fibre (NDF; 74 comparisons), acid detergent fibre (ADF; 59 comparisons), cellulose (24 comparisons), hemicellulose (18 comparisons) and gross energy (GE; 29 comparisons). The absence and inability to describe independent factors which contributed to variation among studies necessitated the use of frequentist random effects and hierarchical Bayesian models in the calculation of summary statistics across studies. Digestibilities of DM, OM, CP, NDF, ADF and hemicellulose were higher (p < 0.05) in goats than sheep when all-forage diets were fed. When concentrates were included in the diets, there were no such differences. Differences between goats and sheep in DM intake were found to be non-significant. Differences in nutrient digestibilities of forages as sole feed implies that species-specific values have to be used in feed formulation and feeding strategies. However, caution is needed when extrapolating results from stall-feeding, which is how digestibility data are usually measured, to grazing conditions.
- MeSH
- Bayesova věta MeSH
- dietní proteiny MeSH
- druhová specificita MeSH
- energetický metabolismus MeSH
- fyziologie výživy zvířat * MeSH
- gastrointestinální trakt fyziologie MeSH
- kozy fyziologie MeSH
- krmivo pro zvířata analýza MeSH
- ovce fyziologie MeSH
- potravní vláknina MeSH
- trávení fyziologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- metaanalýza MeSH
- práce podpořená grantem MeSH
