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排序方式: 共有123条查询结果,搜索用时 15 毫秒
41.
Tizazu H. Mekonnen Paolo G. Mussone Natisha Stashko Phillip Y. Choi David C. Bressler 《Process Biochemistry》2013,48(5-6):885-892
The purpose of this study was to characterize proteinacious material recovered from cattle tissues known as specified risk materials (SRM) hydrolyzed according to two protocols approved by the Canadian Food Inspection Agency and Food and Drug Administration and to evaluate its potential for non-food/feed value-added applications. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), size exclusion high performance liquid chromatography (SEC-HPLC), and free amino acid determination methods were adopted to measure the extent of protein cleavage and the average molecular weight of hydrolyzates, and to identify the reactive functionalities available. Molecular weight analysis revealed that the alkaline hydrolysis protocol cleaved the proteins more severely than thermal hydrolysis. Both protocols narrowed the molecular weight distribution of the proteins and increased their solubility in water. Several active functional groups amenable to further chemical processing were identified in the protein hydrolyzates. In conclusion, this work demonstrated that both hydrolytic protocols can be adopted as pre-processing steps to produce safe and renewable proteinacious feedstock for industrial applications. 相似文献
42.
Intracellular localization of Xenopus small heat shock protein, hsp30, in A6 kidney epithelial cells
Small heat shock proteins (shsps) are molecular chaperones that are inducible by environmental stress. In this study, immunocytochemical analysis and laser scanning confocal microscopy revealed that the shsp family, hsp30, was localized primarily in the cytoplasm of Xenopus A6 kidney epithelial cells after heat shock or sodium arsenite treatment. Heat shock-induced hsp30 was enriched in the perinuclear region with some immunostaining in the nucleus but not in the nucleolus. In sodium arsenite-treated cells hsp30 was enriched towards the cytoplasmic periphery as well as showing some immunostaining in the nucleus. At higher heat shock temperatures (35 degrees C) or after 10 microM sodium arsenite treatment, the actin cytoskeleton displayed some disorganization that co-localized with areas of hsp30 enrichment. Treatment of A6 cells with 50 microM sodium arsenite induced a collapse of the cytoskeleton around the nucleus. These results coupled with previous studies suggest that stress-inducible hsp30 acts as a molecular chaperone primarily in the cytoplasm and may interact with cytoskeletal proteins. 相似文献
43.
Kinetics and mechanism for reduction of halo- and haloam(m)ine platinum(IV) complexes by l-ascorbate
Kelemu Lemma Donald A. HouseNegussie Retta Lars I. Elding 《Inorganica chimica acta》2002,331(1):98-108
Reduction of the model platinum(IV) complexes cis-[PtCl4(NH3)2] (1), trans-[PtCl4(NH3)2] (2), trans-[PtCl2(en)2]2+ (3), trans-[PtBr2(NH3)4]2+ (4), [PtCl6]2− (5), and [PtBr6]2− (6) with l-ascorbic acid (H2Asc) in 1.0 M aqueous medium at 25 °C in the region 1.75≤pH≤7.20 has been investigated using stopped-flow spectrophotometry. The redox reactions follow the rate law: −d[Pt(IV]/dt=k[H2Asc]tot[Pt(IV)] where k is a pH-dependent second-order rate constant and [H2Asc]tot, the total concentration of ascorbic acid. The pH-dependence of k is attributed to parallel reduction of Pt(IV) by the protolytic species HAsc− and Asc2−. Analysis of the kinetics data reveals that the ascorbate anion Asc2− is up to seven orders of magnitude more reactive than HAsc− while H2Asc is unreactive. Electron transfer from HAsc−/Asc2− to the Pt(IV) compounds is suggested to take place by a mechanism involving a reductive attack on any one of the mutually trans-halide ligands by Asc2− and/or HAsc− forming a halide-bridged activated complex. The rapid reduction of these complexes supports the assumption that ascorbate Asc2− might be an important reductant at physiological conditions for anticancer active Pt(IV) pro-drugs capable of undergoing reductive trans elimination. The parameters ΔH≠ and ΔS≠ for reduction of Pt(IV) with Asc2− have been determined from the study of the temperature dependence of k. 相似文献
44.
Background
Outpatient Therapeutic feeding Program (OTP) brings the services for management of Severe Acute Malnutrition (SAM) closer to the community by making services available at decentralized treatment points within the primary health care settings, through the use of ready-to-use therapeutic foods, community outreach and mobilization. Little is known about the program outcomes. This study revealed the levels of program outcome indictors and determinant factors to recovery rate.Methods
A retrospective cohort study was conducted on 628 children who had been managed for SAM under OTP from April/2008 to January/2012. The children were selected using systematic random sampling from 12 health posts and 4 health centers. The study relied on information of demographic characteristics, anthropometries, Plumpy''Nut, medical problems and routine medications intakes. The results were estimated using Kaplan-Meier survival curves, log-rank test and Cox-regression.Results
The recovery, defaulter, mortality and weight gain rates were 61.78%, 13.85%, 3.02% and 5.23 gm/kg/day, respectively. Routine medications were administered partially and children with medical problems were managed inappropriately under the program. As a child consumed one more sachet of Plumpy''Nut, the recovery rate from SAM increased by 4% (HR = 1.04, 95%-CI = 1.03, 1.05, P<0.001). The adjusted hazard ratios to recovery of children with diarrhea, appetite loss with Plumpy''Nut and failure to gain weight were 2.20 (HR = 2.20, 95%-CI = 1.31, 3.41, P = 0.001), 4.49 (HR = 1.74, 95%-CI = 1.07, 2.83, P = 0.046) and 3.88 (HR = 1.95, 95%-CI = 1.17, 3.23, P<0.001), respectively. Children who took amoxicillin and de-worming had 95% (HR = 1.95, 95%-CI = 1.17, 3.23) and 74% (HR = 1.74, 95%-CI = 1.07, 2.83) more probability to recover from SAM as compared to those who didn''t take them.Conclusions
The OTP was partially successful. Management of children with comorbidities under the program and partial administration of routine drugs were major threats for the program effectiveness. The stakeholders should focus on creating the capacity of the OTP providers on proper management of SAM to achieve fully effective program. 相似文献45.
Franziska Trede Anna Lemkul Anagaw Atickem Jacinta C. Beehner Thore J. Bergman Ryan Burke Peter J. Fashing Sascha Knauf Addisu Mekonnen Amera Moges Nga Nguyen Christian Roos Dietmar Zinner 《Zoologica scripta》2020,49(6):659-667
The subspecific taxonomy and distribution of geladas (Theropithecus gelada Rüppell, 1835) remains uncertain. Recent molecular studies based on mitochondrial sequence data revealed a geographically structured, three-deme population, suggesting that there are three evolutionary units of geladas. However, mitochondrial distributions do not always recover population relationships, particularly in taxa with a complex history of isolation and gene flow. We therefore analysed the nuclear genetic population structure of the global gelada population based on 20 microsatellite loci in 43 samples from across its geographic range. FST values, a STRUCTURE analysis and a principal coordinate analysis (PCoA) confirmed the three-deme population structure corresponding to the mitochondrial population structure. Therefore, our analyses provide additional support for three evolutionary units in geladas, corresponding to (a) a northern (north of Lake Tana, primarily in the Simien Mountains, previously classified as Theropithecus gelada gelada Rüppell, 1835), (b) a central (between Addis Ababa and the highlands east of Lake Tana, previously classified as Theropithecus gelada obscurus Heuglin, 1863) and (c) a southern (south of the Rift Valley, previously tentatively classified as Theropithecus gelada arsi Shotake et al., 2016, Anthropological Science, 124, 157) population. These results pave the way for future conservation decisions and highlight that the gelada population boundaries need more fine-grained genetic sampling and phenotypic analyses, in particular for their taxonomic ranking. 相似文献
46.
Daniel E. Elmowitz Lemma Ebssa Albrecht M. Koppenhöfer 《Entomologia Experimentalis et Applicata》2013,148(3):246-258
Entomopathogenic nematodes (EPNs) are obligate pathogens known to naturally persist in many habitats. Because survival is a fundamental component of persistence, we investigated whether vertical movement and other avoidance behaviors (i.e., in‐host survival and latent infection), previously speculated as viable survival mechanisms, are exhibited during the cooler months in a temperate turfgrass habitat. The vertical distribution of populations of two EPN species, Steinernema scarabaei Stock & Koppenhöfer (Rhabditida: Steinernematidae) and Heterorhabditis bacteriophora Poinar (Rhabditida: Heterorhabditidae), and two important hosts of these EPN species, the white grub species Popillia japonica Newman and Anomala orientalis Waterhouse (both Coleoptera: Scarabaeidae), were regularly monitored in turf plots from October through April in two consecutive years. Entomopathogenic nematode vertical distribution showed limited changes for H. bacteriophora but none for S. scarabaei. Recovery of H. bacteriophora showed a strong and consistent decline at 0–4 cm depth in the 1st year and a weaker decline at 4–10 cm in the 1st year and at 0–4 cm in the 2nd year. Due to high variability in the data, it was not possible to determine whether the decline in the upper soil layers was due to downward migration or attrition of infective juvenile nematodes. The decline occurred mostly during the first half of the season before the soil froze to any significant extent. The vertical distribution of both white grub species changed with temperature during fall and spring, but not during winter. Overwintering infective juveniles were only recovered in the soil. There was no evidence for successful in‐host survival or latent infection by the nematodes in endemic white grub populations. 相似文献
47.
Although it is increasingly being recognized that drug-target interaction networks can be powerful tools for the interrogation of systems biology and the rational design of multitargeted drugs, there is no generalized, statistically validated approach to harmonizing sequence-dependent and pharmacology-dependent networks. Here we demonstrate the creation of a comprehensive kinome interaction network based not only on sequence comparisons but also on multiple pharmacology parameters derived from activity profiling data. The framework described for statistical interpretation of these network connections also enables rigorous investigation of chemotype-specific interaction networks, which is critical for multitargeted drug design. 相似文献
48.
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50.
J Yukich O Briët MT Bretscher A Bennett S Lemma Y Berhane TP Eisele J Keating T Smith 《PloS one》2012,7(8):e42861
As some malaria control programs shift focus from disease control to transmission reduction, there is a need for transmission data to monitor progress. At lower levels of transmission, it becomes increasingly more difficult to measure precisely, for example through entomological studies. Many programs conduct regular cross sectional parasite prevalence surveys, and have access to malaria treatment data routinely collected by ministries of health, often in health management information systems. However, by themselves, these data are poor measures of transmission. In this paper, we propose an approach for combining annual parasite incidence and treatment data with cross-sectional parasite prevalence and treatment seeking survey data to estimate the incidence of new infections in the human population, also known as the force of infection. The approach is based on extension of a reversible catalytic model. The accuracy of the estimates from this model appears to be highly dependent on levels of detectability and treatment in the community, indicating the importance of information on private sector treatment seeking and access to effective and appropriate treatment. 相似文献