Although halophilic archaea are rich in natural environments, their biotechnological applications are not as prevalent as those of other extremophiles, such as thermophiles and alkaliphiles. This study presents an simple method to prepare a hydrogel composite using crude cell lysate of a halophilic archaea, Halorubrum ejinoor sp. (H.e.) which was isolated from a saline lake in Inner Mongolia, China. Furthermore, formation mechanism and potential applications of the hydrogel as an adsorbing material are discussed.
ResultsHalorubrum ejinoor sp. (H.e.) cell lysate was firstly prepared by adding pure water onto the H.e. cell pellet, followed by a short incubation at 60 °C. The cell lysate was injected into different metal ion (or H+) solutions to obtain the hydrogel composite. It was observed that H+, Fe3+, La3+, Cu2+, and Ca2+ induced gelation of the cell lysate, while Fe2+, Co2+, Ni2+, Mg2+, Na+, and K+ did not. DNA and extracellular polysaccharides (EPS) in the H.e. cell lysate were found to be responsible for the gelation reaction. These results suggest that DNA and EPS should be crosslinked by metal ions (or H+) and form a networked structure in which the metal ion (or H+) serves as an anchor point. Potential application of the hydrogel as an adsorbing material was explored using La3+-induced H.e. hydrogel composite. The hydrogel composite can adsorb the fluoride, phosphate and DNA-binding carcinogenic agents, such as acridine orange.
ConclusionsThe simplicity and cost effectiveness of the preparation method might make H.e. hydrogel a promising adsorbing material. This work is expected to expand the technical applications of haloarchaea.
相似文献A polyphasic analysis was performed on a novel bacterium, designated strain KMU-143T, which was isolated from seawater collected in the Republic of Korea.
MethodsA novel marine bacterium KMU-143T was analyzed and described using a polyphasic taxonomic method including 16S rRNA gene sequence analysis, DNA–DNA hybridization, and physiological, biochemical, and chemotaxonomic analyses.
ResultsStrain KMU-143T was Gram-stain-negative, strictly aerobic, oval-shaped, non-motile, and chemoorganoheterotrophic. Phylogenetic analysis based on the 16S rRNA gene sequence demonstrated that the novel marine bacterium belongs to the family Rhodobacteraceae, of the class Alphaproteobacteria, and that it possessed the highest (97.1%) sequence similarity with Sulfitobacter pontiacus ChLG 10T and Sulfitobacter undariae W-BA2T. DNA–DNA relatedness values between strains KMU-143T, S. pontiacus JCM 21789T, and S. undariae KCTC 42200T were less than 70%. The major isoprenoid quinone of the novel isolate was ubiquinone-10 (Q-10) and the major (> 10%) cellular fatty acids were C16:0 and C18:1 ω7c. The genomic DNA G+C content of strain KMU-143T was 56.1 mol%. The polar lipid profile of the strain KMU-143T was found to consist of phosphatidylglycerol, diphosphatidylglycerol, phosphatidylcholine, an unidentified aminolipid, and two unidentified lipids.
ConclusionBased on the discriminative phylogenetic position and combination of genotypic and phenotypic properties, the strain is considered to represent a new species of the genus Sulfitobacter for which the name Sulfitobacter salinus sp. nov. is proposed. The type strain of S. salinus sp. nov. is KMU-143T (= KCCM 90322T = NBRC 113459T).
相似文献To characterize a novel dimethoate amidohydrolase from Sphingomonas sp. DC-6.
ResultsA gene, dmhA, encoding the dimethoate amidohydrolase responsible for transforming dimethoate to dimethoate carboxylic acid and methylamine, was cloned from Sphingomonas sp. DC-6. Sequence analysis and molecular modeling indicate that DmhA shares 31–57 % amino acid sequence identities with other functionally confirmed amidohydrolase. DmhA was expressed in Escherichia coli BL21 (DE3) and purified by Ni–NTA affinity chromatography. The purified DmhA could hydrolyze 4-acetaminophenol, dimethoate and propanil. DmhA activity was optimal at 30 °C and pH 7.5. Hg2+, Zn2+, Cu2+, Cd2+, Tween 80, Triton X-100 or SDS strongly inhibited its activity. The K m and k cat values of DmhA for dimethoate are 0.02 mM and 1.2 s−1, respectively.
ConclusionsDmhA was confirmed to be a novel dimethoate amidohydrolase which could eliminate the toxicity of dimethoate, providing a novel gene resource for the development of pesticide-degrading enzyme preparation and mechanistic study of dimethoate hydrolysis.
相似文献Fluorescence in situ hybridization and molecular markers have confirmed that several chromosomes from Thinopyrum intermedium ssp. trichophorum have been added to a wheat background, which originated from a cross between a wheat– Thinopyrum partial amphiploid and triticale. The lines displayed blue grains and resistance to wheat stripe rust.
Thinopyrum intermedium has been used as a valuable resource for improving the disease resistance and yield potential of wheat. With the aim to transfer novel genetic variation from Th. intermedium species for sustainable wheat breeding, a new trigeneric hybrid was produced by crossing an octoploid wheat–Th. intermedium ssp. trichophorum partial amphiploid with hexaploid triticale. Fluorescence in situ hybridization (FISH) revealed that Thinopyrum chromosomes were transmitted preferably and the number of rye chromosomes tended to decrease gradually in the selfed derivatives of the trigeneric hybrids. Four stable wheat–Th. intermedium chromosome substitution, addition and translocation lines were selected, and a 2JS addition line, two substitution lines of 4JS(4B) and 4J(4B), and a small 4J.4B translocation line were identified by FISH and molecular markers. It was revealed that the gene(s) responsible for blue grains may located on the FL0.60–1.00 of long arm of Th. intermedium-derived 4J chromosome. Disease resistance screenings indicated that chromosomes 4JS and 2JS appear to enhance the resistance to stripe rust in the adult plant stage. The new germplasm with Th. intermedium introgression shows promise for utilization of Thinopyrum chromosome segments in future wheat improvement.
相似文献Rice (Oryza sativa L.), wheat (Triticum aestivum L.) and common bean (Phaseolus vulgaris L.) are major staple food crops consumed worldwide. Zinc (Zn) deficiency represents a common micronutrient deficiency in human populations, especially in regions of the world where staple food crops are the main source of daily calorie intake. Foliar application of Zn fertilizer has been shown to be effective for enriching food crop grains with Zn to desirable amounts for human nutrition. For promoting adoption of this practice by growers, it is important to know whether foliar Zn fertilizers can be applied along with pesticides to wheat, rice and also common bean grown across different soil and environmental conditions.
MethodsThe feasibility of foliar application of zinc sulphate (ZnSO4.7H2O) to wheat, rice and common bean in combination with commonly used five fungicides and nine insecticides was investigated under field conditions at the 31 sites-years of seven countries, i.e., China, India, Pakistan, Thailand, Turkey, Brazil and Zambia.
ResultsSignificant increases in grain yields were observed with foliar Zn/foliar Zn?+?pesticide (5.2–7.7 % of wheat and 1.6–4.2 % of rice) over yields with no Zn treatment. In wheat, as average of all experiments, higher grain Zn concentrations were recorded with foliar Zn alone (41.2 mg kg?1) and foliar Zn?+?pesticide (38.4 mg kg?1) as compared to no Zn treatment (28.0 mg kg?1). Though the magnitude of grain Zn enrichment was lesser in rice than wheat, grain Zn concentrations in brown rice were significantly higher with foliar Zn (24.1 mg kg?1) and foliar Zn?+?pesticide (23.6 mg kg?1) than with no Zn (19.1 mg kg?1). In case of common bean, grain Zn concentration increased from 68 to 78 mg kg?1 with foliar Zn alone and to 77 mg kg?1 with foliar Zn applied in combination with pesticides. Thus, grain Zn enrichment with foliar Zn, without or with pesticides, was almost similar in all the tested crops.
ConclusionsThe results obtained at the 31 experimental site-years of seven countries revealed that foliar Zn fertilization can be realized in combination with commonly-applied pesticides to contribute Zn biofortification of grains in wheat, rice and common bean. This agronomic approach represents a useful practice for the farmers to alleviate Zn deficiency problem in human populations.
相似文献To identify drought stress-responsive conserved microRNA (miRNA) from Dongxiang wild rice (Oryza rufipogon Griff., DXWR) on a genome-wide scale, high-throughput sequencing technology was used to sequence libraries of DXWR samples, treated with and without drought stress.
Results505 conserved miRNAs corresponding to 215 families were identified. 17 were significantly down-regulated and 16 were up-regulated under drought stress. Stem-loop qRT-PCR revealed the same expression patterns as high-throughput sequencing, suggesting the accuracy of the sequencing result was high. Potential target genes of the drought-responsive miRNA were predicted to be involved in diverse biological processes. Furthermore, 16 miRNA families were first identified to be involved in drought stress response from plants.
ConclusionThese results present a comprehensive view of the conserved miRNA and their expression patterns under drought stress for DXWR, which will provide valuable information and sequence resources for future basis studies.
相似文献Plants differ in their ability to use different nitrogen (N) chemical forms, these differences can be related to their ecology and drive community structure. The capacity to uptake intact organic N has been observed in plants of several ecosystems. However, soil organic N uptake by Mediterranean plants is unknown despite organic N being abundant in Mediterranean ecosystems. We compare the uptake of different N forms in two widespread coexisting Mediterranean forest trees with contrasting ecophysiological characteristics: Quercus ilex and Pinus halepensis.
MethodsTo estimate root uptake rate of each N form we used equimolar solutions (1 mM N) of 15NO3 ?, 15NH4 + and 15N-13C glycine.
ResultsNH4 + and glycine were taken up at a similar rate, but faster than NO3 ? in both species. Intact dual labeled glycine was found in both species, demonstrating that both species can absorb intact organic N.
ConclusionsDespite their ecological differences, both species had similar preference for N forms suggesting no fundamental niche complementarity for N uptake. The higher preference for NH4 + and glycine over NO3 ? possibly reflects adaptation to the differing proportions of N forms in Mediterranean soils.
相似文献Arsenate (AsV) and chromate (CrVI) inhibit each other’s uptake and translocation in As-hyperaccumulator Pteris vittata. In the present study, we extended the research to As-sensitive plant Pteris ensiformis to better understand the mechanism of their interactions.
MethodsPlants were exposed to 0, 0.75 or 7.5 mg L?1 AsV and 0, 0.52, or 5.2 mg L?1 CrVI for 7 d in hydroponics. Arsenic and Cr speciation were determined in nutrient solutions and plant biomass.
ResultsP. ensiformis accumulated high levels of As and Cr in the rhizomes and roots with low levels in the fronds. However, P. ensiformis was much more effective in taking up Cr than As, as much more Cr was accumulated in the roots (306–6015 vs. 87–642 mg kg?1). AsV and CrVI increased each other’s uptake in the rhizomes and roots when co-present. The AsV and CrVI taken up by P. ensiformis were reduced to arsenite (AsIII) and chromite (CrIII), possibly serving as detoxification mechanism.
ConclusionsUptake of As and Cr induced oxidative stress as indicated by increased lipid peroxidation and electrical conductivity. Arsenic and Cr increased each other’s uptake by P. ensiformis.
相似文献