排序方式： 共有14条查询结果，搜索用时 31 毫秒
1.
Andrei V. Grinchenko Alex von Kriegsheim Nikita A. Shved Anna E. Egorova Diana V. Ilyaskina Tatiana D. Karp Nikolay V. Goncharov Irina Y. Petrova Vadim V. Kumeiko 《Marine drugs》2021,19(12)
C1q domain-containing (C1qDC) proteins are a group of biopolymers involved in immune response as pattern recognition receptors (PRRs) in a lectin-like manner. A new protein MkC1qDC from the hemolymph plasma of Modiolus kurilensis bivalve mollusk widespread in the Northwest Pacific was purified. The isolation procedure included ammonium sulfate precipitation followed by affinity chromatography on pectin-Sepharose. The full-length MkC1qDC sequence was assembled using de novo mass-spectrometry peptide sequencing complemented with N-terminal Edman’s degradation, and included 176 amino acid residues with molecular mass of 19 kDa displaying high homology to bivalve C1qDC proteins. MkC1qDC demonstrated antibacterial properties against Gram-negative and Gram-positive strains. MkC1qDC binds to a number of saccharides in Ca2+-dependent manner which characterized by structural meta-similarity in acidic group enrichment of galactose and mannose derivatives incorporated in diversified molecular species of glycans. Alginate, κ-carrageenan, fucoidan, and pectin were found to be highly effective inhibitors of MkC1qDC activity. Yeast mannan, lipopolysaccharide (LPS), peptidoglycan (PGN) and mucin showed an inhibitory effect at concentrations three orders of magnitude greater than for the most effective saccharides. MkC1qDC localized to the mussel hemal system and interstitial compartment. Intriguingly, MkC1qDC was found to suppress proliferation of human adenocarcinoma HeLa cells in a dose-dependent manner, indicating to the biomedical potential of MkC1qDC protein. 相似文献
2.
Nikita S. Eriksen-Hamel Alicia B. Speratti Joann K. Whalen Anne Lgre Chandra A. Madramootoo 《Soil & Tillage Research》2009,104(2):311-316
Conventional tillage creates soil physical conditions that may restrict earthworm movement and accelerate crop residue decomposition, thus reducing the food supply for earthworms. These negative impacts may be alleviated by retaining crop residues in agroecosystems. The objective of this study was to determine the effects of various tillage and crop residue management practices on earthworm populations in the field and earthworm growth under controlled conditions. Population assessments were conducted at two long-term (15+ years) experimental sites in Québec, Canada with three tillage systems: moldboard plow/disk harrow (CT), chisel plow or disk harrow (RT) and no tillage (NT), as well as two levels of crop residue inputs (high and low). Earthworm growth was assessed in intact soil cores from both sites. In the field, earthworm populations and biomass were greater with long-term NT than CT and RT practices, but not affected by crop residue management. Laboratory growth rates of Aporrectodea turgida (Eisen) in intact soil cores were affected by tillage and residue inputs, and were positively correlated with the soil organic C pool, suggesting that tillage and residue management practices that increase the soil organic C pool provide more organic substrates for earthworm growth. The highest earthworm growth rates were in soils from RT plots with high residue input, which differed from the response of earthworm populations to tillage and residue management treatments in the field. Our results suggest that tillage-induced disturbance probably has a greater impact than food availability on earthworm populations in cool, humid agroecosystems. 相似文献
3.
Genze Nikita Bharti Richa Grieb Michael Schultheiss Sebastian J. Grimm Dominik G. 《Plant methods》2020,16(1):1-13
Photosynthesis is one of the most important biological reactions and forms the basis of crop productivity and yield on which a growing global population relies. However, to develop improved plant cultivars that are capable of increased productivity, methods that can accurately and quickly quantify photosynthetic efficiency in large numbers of genotypes under field conditions are needed. Chlorophyll fluorescence imaging is a rapid, non-destructive measurement that can provide insight into the efficiency of the light-dependent reactions of photosynthesis. To test and validate a field-deployed fluorescence imaging system on the TERRA-REF field scanalyzer, leaves of potted sorghum plants were treated with a photosystem II inhibitor, DCMU, to reduce photochemical efficiency (FV/FM). The ability of the fluorescence imaging system to detect changes in fluorescence was determined by comparing the image-derived values with a handheld fluorometer. This study demonstrated that the imaging system was able to accurately measure photochemical efficiency (FV/FM) and was highly correlated (r = 0.92) with the handheld fluorometer values. Additionally, the fluorescence imaging system was able to track the decrease in photochemical efficiency due to treatment of DCMU over a 7 day period. The system’s ability to capture the temporal dynamics of the plants’ response to this induced stress, which has comparable dynamics to abiotic and biotic stressors found in field environments, indicates the system is operating correctly. With the validation of the fluorescence imaging system, physiological and genetic studies can be undertaken that leverage the fluorescence imaging capabilities and throughput of the field scanalyzer. 相似文献
4.
Earthworm growth is affected by fluctuations in soil temperature and moisture and hence, may be used as an indicator of earthworm activity under field conditions. There is no standard methodology for measuring earthworm growth and results obtained in the laboratory with a variety of food sources, soil quantities and container shapes cannot easily be compared or used to estimate earthworm growth in the field. The objective of this experiment was to determine growth rates of the endogeic earthworm Aporrectodea caliginosa (Savigny) over a range of temperatures (5–20 °C) and soil water potentials (−5 to−54 kPa) in disturbed and undisturbed soil columns in the laboratory. We used PVC cores (6 cm diameter, 15 cm height) containing undisturbed and disturbed soil, and 1 l cylindrical pots (11 cm diameter, 14 cm height) with disturbed soil. All containers contained about 500 g of moist soil. The growth rates of juvenile A. caliginosa were determined after 14–28 days. The instantaneous growth rate (IGR) was affected significantly by soil moisture, temperature, and the temperature×moisture interaction, ranging from −0.092 to 0.037 d−1. Optimum growth conditions for A. caliginosa were at 20 °C and −5 kPa water potential, and they lost weight when the soil water potential was −54 kPa for all temperatures and also when the temperature was 5 °C for all water potentials. Growth rates were significantly greater in pots than in cores, but the growth rates of earthworms in cores with undisturbed or disturbed soil did not differ significantly. The feeding and burrowing habits of earthworms should be considered when choosing the container for growth experiments in order to improve our ability to extrapolate earthworm growth rates from the laboratory to the field. 相似文献
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Nikita Martens Melissa Schepers Na Zhan Frank Leijten Gardi Voortman Assia Tiane Ben Rombaut Janne Poisquet Nienke van de Sande Anja Kerksiek Folkert Kuipers Johan W. Jonker Hongbing Liu Dieter Lütjohann Tim Vanmierlo Monique T. Mulder 《Marine drugs》2021,19(4)
We recently found that dietary supplementation with the seaweed Sargassum fusiforme, containing the preferential LXRβ-agonist 24(S)-saringosterol, prevented memory decline and reduced amyloid-β (Aβ) deposition in an Alzheimer’s disease (AD) mouse model without inducing hepatic steatosis. Here, we examined the effects of 24(S)-saringosterol as a food additive on cognition and neuropathology in AD mice. Six-month-old male APPswePS1ΔE9 mice and wildtype C57BL/6J littermates received 24(S)-saringosterol (0.5 mg/25 g body weight/day) (APPswePS1ΔE9 n = 20; C57BL/6J n = 19) or vehicle (APPswePS1ΔE9 n = 17; C57BL/6J n = 19) for 10 weeks. Cognition was assessed using object recognition and object location tasks. Sterols were analyzed by gas chromatography/mass spectrometry, Aβ and inflammatory markers by immunohistochemistry, and gene expression by quantitative real-time PCR. Hepatic lipids were quantified after Oil-Red-O staining. Administration of 24(S)-saringosterol prevented cognitive decline in APPswePS1ΔE9 mice without affecting the Aβ plaque load. Moreover, 24(S)-saringosterol prevented the increase in the inflammatory marker Iba1 in the cortex of APPswePS1ΔE9 mice (p < 0.001). Furthermore, 24(S)-saringosterol did not affect the expression of lipid metabolism-related LXR-response genes in the hippocampus nor the hepatic neutral lipid content. Thus, administration of 24(S)-saringosterol prevented cognitive decline in APPswePS1ΔE9 mice independent of effects on Aβ load and without adverse effects on liver fat content. The anti-inflammatory effects of 24(S)-saringosterol may contribute to the prevention of cognitive decline. 相似文献
7.
Nikita Yu. Zarubin Elena N. Kharenko Olga V. Bredikhina Leonid O. Arkhipov Konstantin V. Zolotarev Anton N. Mikhailov Valeriya I. Nakhod Marina V. Mikhailova 《Marine drugs》2021,19(8)
Waste from fish cutting (heads, swim bladders, fins, skin, and bones) is a high-value technological raw material for obtaining substances and products with a wide range of properties. The possibility of using waste from cutting fish of the Gadidae family: the Alaska pollock (Gadus chalcogrammus) and the Pacific cod (Gadus macrocephalus), processed in the coastal zone, is scientifically substantiated. In this work, a technology has been developed for processing accumulated waste from fish cutting in order to obtain fish gelatin, which is characterized by high protein content (more than 80.0%) and a full set of essential and nonessential amino acids. We studied the quality of fish gelatin obtained from wastes from cutting the fish of the Gadidae family. The possibility of using fish gelatin as a component of fish products is shown; the dose of its introduction into the fish products is substantiated. The data obtained made it possible to recommend the use of fish processing waste products as a gelling component and a source of amino acids in multicomponent food systems. 相似文献
8.
Dana Katz Michael A. DiMattia Dan Sindhikara Hubert Li Nikita Abraham Abba E. Leffler 《Marine drugs》2021,19(7)
Nicotinic acetylcholine receptor (nAChR) subtypes are key drug targets, but it is challenging to pharmacologically differentiate between them because of their highly similar sequence identities. Furthermore, α-conotoxins (α-CTXs) are naturally selective and competitive antagonists for nAChRs and hold great potential for treating nAChR disorders. Identifying selectivity-enhancing mutations is the chief aim of most α-CTX mutagenesis studies, although doing so with traditional docking methods is difficult due to the lack of α-CTX/nAChR crystal structures. Here, we use homology modeling to predict the structures of α-CTXs bound to two nearly identical nAChR subtypes, α3β2 and α3β4, and use free-energy perturbation (FEP) to re-predict the relative potency and selectivity of α-CTX mutants at these subtypes. First, we use three available crystal structures of the nAChR homologue, acetylcholine-binding protein (AChBP), and re-predict the relative affinities of twenty point mutations made to the α-CTXs LvIA, LsIA, and GIC, with an overall root mean square error (RMSE) of 1.08 ± 0.15 kcal/mol and an R2 of 0.62, equivalent to experimental uncertainty. We then use AChBP as a template for α3β2 and α3β4 nAChR homology models bound to the α-CTX LvIA and re-predict the potencies of eleven point mutations at both subtypes, with an overall RMSE of 0.85 ± 0.08 kcal/mol and an R2 of 0.49. This is significantly better than the widely used molecular mechanics—generalized born/surface area (MM-GB/SA) method, which gives an RMSE of 1.96 ± 0.24 kcal/mol and an R2 of 0.06 on the same test set. Next, we demonstrate that FEP accurately classifies α3β2 nAChR selective LvIA mutants while MM-GB/SA does not. Finally, we use FEP to perform an exhaustive amino acid mutational scan of LvIA and predict fifty-two mutations of LvIA to have greater than 100X selectivity for the α3β2 nAChR. Our results demonstrate the FEP is well-suited to accurately predict potency- and selectivity-enhancing mutations of α-CTXs for nAChRs and to identify alternative strategies for developing selective α-CTXs. 相似文献
9.
候鸟可以运用多种定向线索来确定并保持其运动方向,目前已知它们可以使用至少3种罗盘线索,即太阳、恒星及地磁。这些外部线索之间存在怎样的层级关系仍有争议,而他们又是如何校准至一致的参照方向也所知甚少。近年的研究中,有些研究者认为候鸟用日落信息校准地磁罗盘,其他研究者则由于未能观察到这一现象而持否定意见。本文仔细评述了先前研究,认为天生的种间差异是造成各研究者意见不一致的原因,并对种间差异作了详解。 相似文献
10.
Frieda Eivazi Nikita Mullings Mona-Lisa Banks 《Communications in Soil Science and Plant Analysis》2018,49(3):371-379
Experiments were conducted to investigate the impact of commonly used herbicides and surfactants on the activity of acid phosphatase, β-glucosidase, arylsulfatase, β-glucosaminidase, and dehydrogenase, using two soils (silt loam and silty clay loam) from Mid-Missouri, USA. The surfactants used in this study were alkylphenol ethoxylate + alcohol ethoxylate (ACTIVATOR 90), polyethoxylate (Agri-Dex®) and a blend of ammonium sulfate, drift reduction/deposition polymers, and an antifoam agent (THRUST®). The herbicides were glyphosate, atrazine, and bentazon. Surfactants and herbicides were applied to soils at the label rate, either alone or combined. In general, enzyme activity was enhanced more in silt loam soil than in silty clay loam soil. Acid phosphatase displayed the greatest amount of enzymatic activity within soils; dehydrogenase displayed the most inhibition, whilst β-glucosidase and β-glucosaminidase fluctuated based on treatment. ACTIVATOR 90 appeared to have the most inhibitory effect on enzymatic activity within soils compared to the control. 相似文献