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1.
Journal of Soils and Sediments - Complex phenomena of the precipitation and accumulation of calcium carbonate in urban soils and sediments have been studied. They are linked to the interactions...  相似文献   
2.
If they could be easily exfoliated, layered materials would become a diverse source of two-dimensional crystals whose properties would be useful in applications ranging from electronics to energy storage. We show that layered compounds such as MoS(2), WS(2), MoSe(2), MoTe(2), TaSe(2), NbSe(2), NiTe(2), BN, and Bi(2)Te(3) can be efficiently dispersed in common solvents and can be deposited as individual flakes or formed into films. Electron microscopy strongly suggests that the material is exfoliated into individual layers. By blending this material with suspensions of other nanomaterials or polymer solutions, we can prepare hybrid dispersions or composites, which can be cast into films. We show that WS(2) and MoS(2) effectively reinforce polymers, whereas WS(2)/carbon nanotube hybrid films have high conductivity, leading to promising thermoelectric properties.  相似文献   
3.
The sirtuins are members of the histone deacetylase family of proteins that participate in a variety of cellular functions and play a role in aging. We identified a potent inhibitor of sirtuin 2 (SIRT2) and found that inhibition of SIRT2 rescued alpha-synuclein toxicity and modified inclusion morphology in a cellular model of Parkinson's disease. Genetic inhibition of SIRT2 via small interfering RNA similarly rescued alpha-synuclein toxicity. Furthermore, the inhibitors protected against dopaminergic cell death both in vitro and in a Drosophila model of Parkinson's disease. The results suggest a link between neurodegeneration and aging.  相似文献   
4.
5.
Using the approach of sequencing the V3-V4 region of the 16S rRNA gene, we have analysed the bacterial diversity associated with the distinct compartments of the gastrointestinal tract of perch (Perca fluviatilis) and cestodes (Proteocephalus sp.) parasitizing their digestive tract. The dominant microbiota associated with cestodes (Proteocephalus sp.) was represented by bacteria from the genera Serratia, Pseudomonas and Mycoplasma. By comparing the associated microbiota of perch and cestodes, a clear difference in bacterial composition and diversity was revealed between the community from the stomach content and other parts of the gastrointestinal tract of fish. Microbiota associated with cestodes was not significantly different in comparison with microbiota of different subcompartments of perch (mucosa and content of intestine and pyloric caeca) (ADONIS, p > .05) excluding microbiota of stomach content (ADONIS, p ≤ .05). PICRUSt-based functional assessments of the microbial communities of perch and cestodes indicated that they mainly linked in terms of metabolism and environmental information processing and could play an important role in the nutrition and health of host.  相似文献   
6.
Actinomycete strains originating from Moroccan phosphate mines (MPM) were selected for their ability to use the insoluble ground hydroxyapatite called rock phosphate (RP), present in their biotope, as sole phosphate (P) source. Physiological studies carried out with these strains and with the reference strains, Streptomyces lividans and Streptomyces griseus, demonstrated that all strains were able to grown in a synthetic minimal medium (SMM) containing either soluble (SP) or insoluble (RP) phosphate as sole P source. The MPM strains and S. griseus took up glucose much more actively and exhaustively than S. lividans, constituting more abundant glycogen reserves than the latter. All strains took up soluble P at comparable rates, storing it as polyphosphates. In SMM + RP, a sharp increase in the concentration of soluble P was detected in the culture broths of all MPM strains and S. griseus, at stationary phase, but not in that of S. lividans. The P peak detected in the supernatant of these strains correlated with the successive appearance of two compounds absorbing at 320 nm and 430 nm, respectively. These compounds are thought to be strong ion chelators involved in the destruction of the hydroxyapatite structure leading to soluble P release. The good growth of S. lividans in SMM + RP indicated that this strain was also able to release P from RP but consummed it as soon as it was released, unlike the other strains. Our study is expected to lead to the development of a novel type of slow release bio-phosphate fertilizer constituted by the association of the MPM strains and ground RP. This novel product would precisely supply plant needs and thus limit the pollution of the environment.  相似文献   
7.
This study was conducted to characterize the energy metabolism level and the features of muscle growth regulation during the development of Atlantic salmon (Salmo salar) inhabiting the Indera River (Kola Peninsula, Russia). The activities of aerobic and anaerobic enzymes (cytochrome c oxidase and lactate dehydrogenase) and carbohydrate metabolism enzymes (glucose-6-phosphate dehydrogenase, glycerol-3-phosphate dehydrogenase, and aldolase) were measured in muscle and liver tissue. Gene expression levels of myosin heavy chain (MyHC), myostatin (MSTN-1a), and myogenic regulatory factors (MRFs—MyoD1a, MyoD1b, MyoD1c, Myf5, myogenin) were measured in the white muscles of salmon parr of ages 0+, 1+, 2+, and 3+ and smolts of ages 2+ and 3+. Multidirectional changes in the activity of enzymes involved in aerobic and anaerobic energy metabolism with age were shown in the white muscles of the parr. The cytochrome c oxidase activity was higher in muscles of underyearlings (0+) and yearlings (1+) and decreased in 2+ and 3+ age groups. The activity of lactate dehydrogenase, in contrast, increased with age. The patterns of changes in expression levels of MyoD1a, MyoD1b, myogenin, MyHC, and MSTN-1a at different ages of the parr were similar. Particularly, the expression of these genes peaked in the yearling parr (1+) and then decreased in elder groups. The differences were revealed in parameters studied between the parr and smolts. The level of aerobic and anaerobic metabolism enzyme activities was higher in the white muscles of smolts than in parr. The activity of carbohydrate metabolism enzymes was decreased in the smolts’ livers. The expression levels of MyHC, MyoD1a, MyoD1b, and myogenin were lower in smolts at age 2+ compared to parr. These findings expand our knowledge of age-related and stage-related features of energy metabolism and muscle development regulation in young Atlantic salmon in their natural habitat. The results might be used for monitoring of the salmon population during restoration and rearing.  相似文献   
8.

Purpose

The main aim of the study performed during 6 years was to determine the specific features of heavy metal contamination of soil cover in the city of Rostov-on-Don and its agglomeration. It was supposed to answer the question: Does soil inherit heavy metals mainly from the parent rocks, or they enter the soil mainly as a result of anthropogenes in the city condition.

Materials and methods

Seventeen soil profiles were established in different parts of the Rostov agglomeration, within the city and in the urbanized agricultural region. The following objects were studied: (1) calcareous ordinary chernozem under steppe vegetation (fallow) and under trees (parks): soils of natural structure insignificantly affected by urbanization processes; (2) urbostratozems: soils of natural structure overlain by loose anthropogenic deposits; (3) screened urbostratozems (or ecranozems): soils of natural structure overlain by asphalt and/or another impermeable surface. The contents of heavy metals were determined by X-ray fluorescence. The degree of soil contamination with heavy metals was assessed by comparing their content with the MPC values (danger coefficient method) or using the total contamination factor Zc.

Results and discussion

The comparison of chernozems under different plant covers shows that the woody plants capable of retaining moisture in the soil and more deeply wetting the soil layer decrease the accumulation of vanadium, chromium, cobalt, nickel, and copper in the surface layer. The accumulation coefficients of these metals in urbostratozems are still lower for some reason. At the same time, an increase in the accumulation of zinc and lead is observed in the surface layer of soils under the forest canopy, as well as in the urbostratozems. In the Urbostratozems, screened by dense surfaces, a high variation is observed, which is related to the different times of soil sealing with asphalt.

Conclusions

The results showed that the concentrations of most elements in the parent rock of Rostov-on-Don exceed the background values, and those of some elements exceed the MPC levels. The main source of accumulation of these elements in the soil profile is the parent rock. Additional input from anthropogenic sources is contributed by the accumulation of such elements as chromium, nickel, zinc, and lead.
  相似文献   
9.
Elephant grass [Pennisetum purpureum S.; syn. Cenchrus purpureus (Schumach.) Morrone] is an important global forage crop and is recognized for high yields of herbage with good nutritive value. It also has high biomass potential to be utilized as a biofuel feedstock. Whereas several previous genetic studies adapted simple sequence repeat (SSR) markers from pearl millet [Pennisetum glaucum (L.) R.Br.] for investigations in elephant grass, the present study developed SSR markers from 3536 DNA sequences derived from 16 elephant grass entries. A total of 3866 SSRs were identified including 1028 monomeric, 2019 dimeric, 735 trimeric, 49 tetrameric, 20 pentameric and 15 hexameric repeat motifs. Three hundred and seven sequences contained more than one repeated motif, and 154 SSRs were present in compound formation. Susequenctly,  four elephant grass and two pearl millet genotypes were chosen to validate 727 SSR markers. Of these, 628 markers produced visually detectable amplification products, including 73 (11.6%) polymorphic ones across all six genotypes. Polymorphism between the four elephant grass genotypes was revealed by 316 (50.6%) markers with diversity index values ranging from 0.75 to 0.38. Dimeric SSRs had the highest polymorphic rate (48.7%). These validated SSR markers had 58.6% (368 of 628) transferability rate to pearl millet. The availability of these polymorphic SSR markers will support advanced genetic studies in P. purpureum and its relatives.  相似文献   
10.

Purpose

The aim of this work was to select and assess the efficiency of different amendments applied to ordinary chernozems artificially contaminated with heavy metals (Zn and Pb).

Materials and methods

The effect of different amendments on ordinary chernozem contaminated with Zn and Pb acetate salts was studied in a long-term 3-year field experiment. Glauconite, chalk, manure, and their combinations were chosen as ameliorating agents. Spring barley (Hordeum sativum) was used as test culture for three successive years. The heavy metal concentration in all the soil samples decomposed by HF?+?HClO4 was determined by atomic absorption spectrophotometry (AAS). One normal concentration of CH3COONH4 at pH 4.8 was used to estimate the actual mobility of metals. The compounds of heavy metals extracted by 1 N HCl are regarded as mobile compounds. The concentration of metals in the plants was determined using the dry combustion in a mixture of HNO3 and HCl at 450 °C. The content of heavy metals in extracts from soil and plant samples was determined by AAS.

Results and discussion

The content of weakly bound metal compounds increased upon the contamination of the soil with Pb and Zn salts, which led to a low quality of barley grown in these soils. Metal concentrations in the barley grain exceeded the maximum permissible concentrations (MPCs). The content of Zn and Pb in grains was higher than the MPC for at least 3 years after the soil pollution. The application of amendments significantly decreased the mobility of metals, and the simultaneous application of chalk and manure was most significant. The share of weakly bound metal compounds in the contaminated soils decreased to the level typical for the clean soils or even below.

Conclusions

The combined application of chalk and manure to Zn- and Pb-contaminated ordinary chernozems decreased the content of weakly bound metal compounds in the soil and lowered their concentrations in barley plants. The polyfunctional properties of the soil components with respect to their capacity for metal fixation were established. The decrease in the intensity of Zn accumulation in grains of barley shows the presence of a barrier at the root–stalk and stalk–grain interfaces.
  相似文献   
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