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排序方式: 共有1167条查询结果,搜索用时 15 毫秒
11.
12.
The objective of this study was to perform a market survey on dry pet foods using enzyme-linked immunosorbent assay (ELISA) to detect total aflatoxins (AFs), ochratoxin A (OTA), and deoxynivalenol (DON). Pet food products (n?=?58) marketed for dogs, cats, birds, and rabbits were tested in duplicate with ELISA, and results above the limit of quantitation were confirmed using liquid chromatography tandem mass spectrometry (LC-MS/MS). OTA was detected in one product (rabbit food) and AFs were detected in two products (one dog treat and one bird treat). In contrast, DON was detected in the majority (74%) of products tested. Bird and rabbit products were the most affected by DON, with levels above 0.5 μg/g in 50 and 80% of samples, respectively. One rabbit sample tested positive for both OTA and DON. Overall, the findings of this study revealed a low incidence of AFs and OTA in commercial pet food. Although DON was detected in numerous products, the levels were well below those associated with acute toxic effects. 相似文献
13.
Ly Na Huynh Adama Zan Diarra Quang Luan Pham Nhiem Le-Viet Jean-Michel Berenger Van Hoang Ho Xuan Quang Nguyen Philippe Parola 《PLoS neglected tropical diseases》2021,15(9)
Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been reported as a promising and reliable tool for arthropod identification, including the identification of alcohol-preserved ticks based on extracted leg protein spectra. In this study, the legs of 361 ticks collected in Vietnam, including 251 Rhiphicephalus sanguineus s.l, 99 Rhipicephalus (Boophilus) microplus, two Amblyomma varanensis, seven Dermacentor auratus, one Dermacentor compactus and one Amblyomma sp. were submitted for MALDI-TOF MS analyses. Spectral analysis showed intra-species reproducibility and inter-species specificity and the spectra of 329 (91%) specimens were of excellent quality. The blind test of 310 spectra remaining after updating the database with 19 spectra revealed that all were correctly identified with log score values (LSV) ranging from 1.7 to 2.396 with a mean of 1.982 ± 0.142 and a median of 1.971. The DNA of several microorganisms including Anaplasma platys, Anaplasma phagocytophilum, Anaplasma marginale, Ehrlichia rustica, Babesia vogeli, Theileria sinensis, and Theileria orientalis were detected in 25 ticks. Co-infection by A. phagocytophilum and T. sinensis was found in one Rh. (B) microplus. 相似文献
14.
15.
Histidine decarboxylase of Lactobacillus 30a. Sequences of the overlapping peptides, the complete alpha chain, and prohistidine decarboxylase 总被引:1,自引:0,他引:1
Q K Huynh P A Recsei G L Vaaler E E Snell 《The Journal of biological chemistry》1984,259(5):2833-2839
The complete amino acid sequence of the alpha chain of histidine decarboxylase of Lactobacillus 30a has been established by isolation and analysis of the eight methionine-containing tryptic peptides of this chain. These peptides provide the overlaps required to order all nine peptides derived by complete cyanogen bromide cleavage of the alpha chain (Huynh, Q.K., Vaaler, G.L., Recsei, P.A., and Snell, E.E. (1984) J. Biol. Chem. 259, 2826-2832). Ordering of six of the latter peptides was confirmed by isolation and analysis of four peptides derived by incomplete cyanogen bromide cleavage. The alpha chain is composed of 226 residues and has a molecular weight of 24,892 calculated from the sequence. These results and the previously determined sequence of the beta chain (Vaaler, G.L., Recsei, P.A., Fox, J.L., and Snell, E.E. (1982) J. Biol. Chem. 257, 12770-12774) establish the complete amino acid sequence of the enzyme and of the pi chain of prohistidine decarboxylase. The latter is composed of 307 amino acids and has a calculated molecular weight of 33,731. Four segments of the pi chain sequence are repeated. The bond between Ser-81 and Ser-82 that is cleaved during proenzyme activation is in an uncharged portion of the sequence that is rich in serine and threonine residues and is predicted to be part of a beta sheet structure. 相似文献
16.
Amanda K. Frank Duy C. Tran Roy W. Qu Bradley A. Stohr David J. Segal Lifeng Xu 《PLoS genetics》2015,11(7)
Dyskeratosis Congenita (DC) is a heritable multi-system disorder caused by abnormally short telomeres. Clinically diagnosed by the mucocutaneous symptoms, DC patients are at high risk for bone marrow failure, pulmonary fibrosis, and multiple types of cancers. We have recapitulated the most common DC-causing mutation in the shelterin component TIN2 by introducing a TIN2-R282H mutation into cultured telomerase-positive human cells via a knock-in approach. The resulting heterozygous TIN2-R282H mutation does not perturb occupancy of other shelterin components on telomeres, result in activation of telomeric DNA damage signaling or exhibit other characteristics indicative of a telomere deprotection defect. Using a novel assay that monitors the frequency and extension rate of telomerase activity at individual telomeres, we show instead that telomerase elongates telomeres at a reduced frequency in TIN2-R282H heterozygous cells; this recruitment defect is further corroborated by examining the effect of this mutation on telomerase-telomere co-localization. These observations suggest a direct role for TIN2 in mediating telomere length through telomerase, separable from its role in telomere protection. 相似文献
17.
In most eukaryotes, telomeric DNA consists of repeats of a short motif that includes consecutive guanines and may hence fold into G-quadruplexes. Budding yeasts have telomeres composed of longer repeats and show variation in the degree of repeat homogeneity. Although telomeric sequences from several organisms have been shown to fold into G-quadruplexes in vitro, surprisingly, no study has been dedicated to the comparison of G-quadruplex folding and stability of known telomeric sequences. Furthermore, to our knowledge, folding of yeast telomeric sequences into intramolecular G-quadruplexes has never been investigated. Using biophysical and biochemical methods, we studied sequences mimicking about four repetitions of telomeric motifs from a variety of organisms, including yeasts, with the aim of comparing the G-quadruplex folding potential of telomeric sequences among eukaryotes. G-quadruplex folding did not appear to be a conserved feature among yeast telomeric sequences. By contrast, all known telomeric sequences from eukaryotes other than yeasts folded into G-quadruplexes. Nevertheless, while G(3)T(1-4)A repeats (found in a variety of organisms) and G(4)T(2,4) repeats (found in ciliates) folded into stable G-quadruplexes, G-quadruplexes formed by repetitions of G(2)T(2)A and G(2)CT(2)A motifs (found in many insects and in nematodes, respectively) appeared to be in equilibrium with non-G-quadruplex structures (likely hairpin-duplexes). 相似文献
18.
In Japan, the green seaweed Monostroma is an important source of humanfood. Monostroma nitidum Wittrock (Japanese name: hitoegusa)
is cultivated in brackish waters and estuaries of central to southern Japan. The green seaweed Monostroma grows in the brackish
water area in the upper part of the intertidal zone in the warm waters. Artificial seed culture began with the collection
of many gametes in April. The resultant zygotes were allowed to adhere to plastic settlement boards (20 cm long and 10 cm
wide). The zygoteboards were then cultured in tanks (1 ×2 ×0.5 m) with fertiliser in a controlled growth room (10–87 μmol
photon m-2s-1). The cultivated zygotes on the board in the indoor tanks gradually increased in size from 10 to 40 μm in diameter during
May to early August. Zygote growth became slowed at the end of August. The zygotesmatured in early September, and the plates
were transferred into culture tanks in a dark room for dark treatment. Maturation of the zygote was promoted by providing
dark conditions for two weeks. The production of a concentrated zoospore solution from the mature blades was achieved by adding
fresh water at temperature 2–3 °C above that of the seeding vats. Zoospores were released in large numbers when exposed to
strong irradiance of 100 μmol photon m-2 s-1 for 30 min. The zygotes produced flat unicellular fronds at the germling stage. The technology of artificial seed culture
and zoospore release from the zygotes is based mainly on these experiments.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
19.
Ngo JC Giang K Chakrabarti S Ma CT Huynh N Hagopian JC Dorrestein PC Fu XD Adams JA Ghosh G 《Molecular cell》2008,29(5):563-576
The 2.9 A crystal structure of the core SRPK1:ASF/SF2 complex reveals that the N-terminal half of the basic RS domain of ASF/SF2, which is destined to be phosphorylated, is bound to an acidic docking groove of SRPK1 distal to the active site. Phosphorylation of ASF/SF2 at a single site in the C-terminal end of the RS domain generates a primed phosphoserine that binds to a basic site in the kinase. Biochemical experiments support a directional sliding of the RS peptide through the docking groove to the active site during phosphorylation, which ends with the unfolding of a beta strand of the RRM domain and binding of the unfolded region to the docking groove. We further suggest that the priming of the first serine facilitates directional substrate translocation and efficient phosphorylation. 相似文献
20.
V. O. Mokievsky A. V. Tchesunov A. A. Udalov Nguen Duy Toan 《Russian Journal of Marine Biology》2011,37(4):272-283
Meiobenthic studies were performed in an intertidal area in the Be River estuary (Nha Trang Bay, Vietnam). The study area
is an area of riverine-type mangroves that have been heavily damaged by human impacts, including timber cutting and waste.
Three biotopes are situated in the middle intertidal zone: a fringe of Rhizophora stylosa, a bush area composed of Avicennia aff. alba behind it, and muddy sand with fiddler crabs (Uca spp.), which is free of mangrove plants. Three replicate samples of meiobenthos were collected in each biotope and each sample
was subdivided into two layers: 0–1 and 1–4 cm. The abundance of metazoan meiobenthos varied from 735 specimens/10 cm2 in the Uca spp. biotope to 244 specimens/10 cm2 beneath the Rhizophora trees. Six taxonomic groups of high rank were found among the meiofauna: Nematoda, Copepoda (Harpacticoida), Oligochaeta,
Turbellaria, Kinorhyncha, and Foraminifera (Allogromiida). The spatial variability of meiobenthos and its key taxa was estimated
and the spatial distribution patterns of free-living nematode species were described. About 90% of the total meiobenthos inhabited
the upper 0–1 cm of the sediments. Nematodes constituted 90–95% of all meiobenthic organisms in the samples. A total of 48
species of free-living nematodes were found in the investigated mangrove intertidal area. In terms of species composition
and set of dominants, the nematode community is comprised of three local assemblages: one of them inhabits the uppermost centimeter
in the Uca and Avicennia biocenoses; the second assemblage occupies the upper sediment layer in the Rhizophora stand; a less abundant but specific assemblage of several nematode species occurs in the subsurface sediments at all three
sites. 相似文献