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1.
The effect of high hydrostatic pressure (HHP) on the susceptibility of potato starch (25%, w/v) suspended in water to degradation by exposure to bacterial α-amylase (0.02%, 0.04% and 0.06%, w/v) for 40 min at 25°C was investigated. Significant differences (p < 0.05) in the structure, morphology and physicochemical properties were observed. HHP-treated potato starch (PS) exposed to α-amylase (0.06%, w/v) showed a significantly greater degree of hydrolysis and amount of reducing sugar released compared to α-amylase at a concentration of 0.04% (w/v) or 0.02% (w/v). Native PS (NPS) granules have a spherical and elliptical form with a smooth surface, whereas the hydrolyzed NPS (hNPS) and hydrolyzed HHP-treated PS granules showed irregular and ruptured forms with several cracks and holes on the surface. Hydrolysis of HHP-treated PS by α-amylase could decrease the average granule size significantly (p <0.05) from 29.43 to 20.03 μm. Swelling power decreased and solubility increased with increasing enzyme concentration and increasing pressure from 200–600 MPa, with the exception of the solubility of HHP-treated PS at 600 MPa (HHP600 PS). Fourier transform infrared spectroscopy (FTIR) showed extensive degradation of the starch in both the ordered and the amorphous structure, especially in hydrolyzed HHP600 PS. The B-type of hydrolyzed HHP600 PS with α-amylase at a concentration 0.06% (w/v) changed to a B+V type with an additional peak at 2θ = 19.36°. The HHP600 starch with 0.06% (w/v) α-amylase displayed the lowest value of T
o (onset temperature), T
c (conclusion temperature) and ΔH
gel (enthalpies of gelatinization). These results indicate the pre-HHP treatment of NPS leads to increased susceptibility of the granules to enzymatic degradation and eventually changes of both the amorphous and the crystalline structures. 相似文献
2.
Reaux-Le Goazigo A Bodineau L De Mota N Jeandel L Chartrel N Knauf C Raad C Valet P Llorens-Cortes C 《American journal of physiology. Endocrinology and metabolism》2011,301(5):E955-E966
Neuronal networks originating in the hypothalamic arcuate nucleus (Arc) play a fundamental role in controlling energy balance. In the Arc, neuropeptide Y (NPY)-producing neurons stimulate food intake, whereas neurons releasing the proopiomelanocortin (POMC)-derived peptide α-melanocyte-stimulating hormone (α-MSH) strongly decrease food intake. There is growing evidence to suggest that apelin and its receptor may play a role in the central control of food intake, and both are concentrated in the Arc. We investigated the presence of apelin and its receptor in Arc NPY- and POMC-containing neurons and the effects of apelin on α-MSH release in the hypothalamus. We showed, by immunofluorescence and confocal microscopy, that apelin-immunoreactive (IR) neuronal cell bodies were distributed throughout the rostrocaudal extent of the Arc and that apelin was strongly colocalized with POMC, but weakly colocalized with NPY. However, there were numerous NPY-IR nerve fibers close to the apelin-IR neuronal cell bodies. By combining in situ hybridization with immunohistochemistry, we demonstrated the presence of apelin receptor mRNA in Arc POMC neurons. Moreover, using a perifusion technique for hypothalamic explants, we demonstrated that apelin-17 (K17F) increased α-MSH release, suggesting that apelin released somato-dendritically or axonally from POMC neurons may stimulate α-MSH release in an autocrine manner. Consistent with these data, hypothalamic apelin levels were found to be higher in obese db/db mice and fa/fa Zucker rats than in wild-type animals. These findings support the hypothesis that central apelin is involved in regulating body weight and feeding behavior through the direct stimulation of α-MSH release. 相似文献
3.
Biocides are currently the primary mitigation method to control sulfate-reducing bacteria (SRB) in biofouling, reservoir souring
and microbiologically influenced corrosion. Increasingly restrictive environmental regulations and safety concerns on biocide
uses demand more efficient dosing of biocides. Chelators have been known to enhance antibiotics because of their properties
such as increasing the permeability of the outer cell membrane of Gram-negative bacteria. Two readily biodegradable chelators,
ethylenediaminedisuccinate (EDDS) and N-(2-hydroxyethyl)iminodiacetic acid (HEIDA) disodium salts that are touted as potential replacements of ethylenediaminetetraacetic
acid (EDTA), were evaluated as potential biocide enhancers for glutaraldehyde and tetrakis hydroxymethyl phosphonium sulfate
(THPS) in their inhibition of planktonic SRB growth. Desulfovibrio vulgaris ATCC 7757 and Desulfovibrio desulfuricans ATCC 14563 were grown in modified ATCC 1249 medium and in enriched artificial seawater, respectively. Laboratory tests in
100 ml anaerobic vials showed that EDDS or HEIDA alone did not inhibit SRB growth. However, when EDDS or HEIDA was combined
with glutaraldehyde or THPS, each of them enhanced the biocide inhibition of planktonic SRB growth. 相似文献
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5.
Markus de Raad Kaan Koper Kai Deng Benjamin P. Bowen Hiroshi A. Maeda Trent R. Northen 《The Journal of biological chemistry》2023,299(3)
Aminotransferases (ATs) catalyze pyridoxal 5′-phosphate–dependent transamination reactions between amino donor and keto acceptor substrates and play central roles in nitrogen metabolism of all organisms. ATs are involved in the biosynthesis and degradation of both proteinogenic and nonproteinogenic amino acids and also carry out a wide variety of functions in photorespiration, detoxification, and secondary metabolism. Despite the importance of ATs, their functionality is poorly understood as only a small fraction of putative ATs, predicted from DNA sequences, are associated with experimental data. Even for characterized ATs, the full spectrum of substrate specificity, among many potential substrates, has not been explored in most cases. This is largely due to the lack of suitable high-throughput assays that can screen for AT activity and specificity at scale. Here we present a new high-throughput platform for screening AT activity using bioconjugate chemistry and mass spectrometry imaging–based analysis. Detection of AT reaction products is achieved by forming an oxime linkage between the ketone groups of transaminated amino donors and a probe molecule that facilitates mass spectrometry-based analysis using nanostructure-initiator mass spectrometry or MALDI–mass spectrometry. As a proof-of-principle, we applied the newly established method and found that a previously uncharacterized Arabidopsis thaliana tryptophan AT-related protein 1 is a highly promiscuous enzyme that can utilize 13 amino acid donors and three keto acid acceptors. These results demonstrate that this oxime–mass spectrometry imaging AT assay enables high-throughput discovery and comprehensive characterization of AT enzymes, leading to an accurate understanding of the nitrogen metabolic network. 相似文献
6.
Sulfate-reducing bacteria (SRB) cause souring and their biofilms are often the culprit in Microbiologically Influenced Corrosion
(MIC). The two most common green biocides for SRB treatment are tetrakis-hydroxymethylphosphonium sulfate (THPS) and glutaraldehyde.
It is unlikely that there will be another equally effective green biocide in the market any time soon. This means more effective
biocide treatment probably will rely on biocide cocktails. In this work a triple biocide cocktail consisting of glutaraldehyde
or THPS, ethylenediaminedisuccinate (EDDS) and methanol was used to treat planktonic SRB and to remove established SRB biofilms.
Desulfovibrio vulgaris (ATCC 7757), a corrosive SRB was used as an example in the tests. Laboratory results indicated that with the addition of
10–15% (v/v) methanol to the glutaraldehyde and EDDS double combination, mitigation of planktonic SRB growth in ATCC 1249
medium and a diluted medium turned from inhibition to a kill effect while the chelator dosage was cut from 2,000 to 1,000 ppm.
Biofilm removal was achieved when 50 ppm glutaraldehyde combined with 15% methanol and 1,000 ppm EDDS was used. THPS showed
similar effects when it was used to replace glutaraldehyde in the triple biocide cocktail to treat planktonic SRB. 相似文献
7.
Katherine E. Horn Stephen D. Glasgow Delphine Gobert Sarah-Jane Bull Tamarah Luk Jacklyn Girgis Marie-Eve Tremblay Danielle McEachern Jean-François Bouchard Michael Haber Edith Hamel Paul Krimpenfort Keith K. Murai Anton Berns Guy Doucet C. Andrew Chapman Edward S. Ruthazer Timothy E. Kennedy 《Cell reports》2013,3(1):173-185
Highlights? DCC and netrin-1 are enriched at synapses in the adult mouse forebrain ? DCC is enriched in the PSD and regulates dendritic spine morphology ? LTP induction and memory formation require DCC expression by neurons ? DCC activation of Src is required for NMDAR-dependent LTP in adult CNS 相似文献
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Hassani R Prasad CK Vineetha KE Vij N Singh P Sud R Yadav S Randhawa GS 《Indian journal of experimental biology》2002,40(10):1110-1120
Ten isoleucine+valine and three leucine auxotrophs of Sinorhizobium meliloti Rmd201 were obtained by random mutagenesis with transposon Tn5 followed by screening of Tn5 derivatives on minimal medium supplemented with modified Holliday pools. Based on intermediate feeding, intermediate accumulation and cross-feeding studies, isoleucine+valine and leucine auxotrophs were designated as ilvB/ilvG, ilvC and ilvD, and leuC/leuD and leuB mutants, respectively. Symbiotic properties of all ilvD mutants with alfalfa plants were similar to those of the parental strain. The ilvB/ilvG and ilvC mutants were Nod-. Inoculation of alfalfa plants with ilvB/ilvG mutant did not result in root hair curling and infection thread formation. The ilvC mutants were capable of curling root hairs but did not induce infection thread formation. All leucine auxotrophs were Nod+ Fix-. Supplementation of leucine to the plant nutrient medium did not restore symbiotic effectiveness to the auxotrophs. Histological studies revealed that the nodules induced by the leucine auxotrophs did not develop fully like those induced by the parental strain. The nodules induced by leuB mutants were structurally more advanced than the leuC/leuD mutant induced nodules. These results indicate that ilvB/ilvG, ilvC and one or two leu genes of S. meliloti may have a role in symbiosis. The position of ilv genes on the chromosomal map of S. meliloti was found to be near ade-15 marker. 相似文献
10.
Association of IL‐37 gene polymorphisms with susceptibility to tuberculosis in Saudi subjects 下载免费PDF全文
Gamal Allam Imad A.A. Mohamed Khaled A. Alswat Said H. Abbadi Raad Nassif Bader J. Alharthi Amre Nasr 《Microbiology and immunology》2016,60(11):778-786
Tuberculosis (TB) is one of the most common infectious diseases worldwide. IL‐37, a novel member of the IL‐1 family, has anti‐inflammatory activity. Various cytokine genes polymorphisms are reportedly associated with susceptibility to TB infection. However, an association between genetic variations in the IL‐37 gene and susceptibility to TB infection has not been investigated. The aim of this case‐control study was therefore to identify such an association in Saudi subjects, in which five single‐nucleotide polymorphisms (SNPs) in the IL‐37 gene were assessed. Serum concentrations of IL‐37 were evaluated using ELISA, and genetic variants genotyped by multiplex PCR and ligase detection reaction. It was found that the C/C genotype of rs2723176 (–6962 A/C) occurs significantly more frequently in patients with active TB and that the C allele of this SNP is associated with TB. In addition, the C allele of rs2723176 SNP was associated with high circulating concentrations of IL‐37. However, the genotype and allele frequency of the other four SNPs (rs3811046, rs3811047, rs2723186 and rs2723187) were not significantly associated with TB infection. In conclusion, the present data suggest that rs2723176 SNP of IL‐37 is involved in the development of TB infection. Furthermore, high circulating concentrations of IL‐37 may have a negative effect on protective immunity against TB infection. 相似文献