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Daren Lee Seth Ruffins Queenie Ng Nikhil Sane Steve Anderson Arthur Toga 《BMC bioinformatics》2010,11(1):608
Background
Digital atlases provide a common semantic and spatial coordinate system that can be leveraged to compare, contrast, and correlate data from disparate sources. As the quality and amount of biological data continues to advance and grow, searching, referencing, and comparing this data with a researcher's own data is essential. However, the integration process is cumbersome and time-consuming due to misaligned data, implicitly defined associations, and incompatible data sources. This work addressing these challenges by providing a unified and adaptable environment to accelerate the workflow to gather, align, and analyze the data. 相似文献3.
Jin Wei Mia Madel Alfajaro Peter C. DeWeirdt Ruth E. Hanna William J. Lu-Culligan Wesley L. Cai Madison S. Strine Shang-Min Zhang Vincent R. Graziano Cameron O. Schmitz Jennifer S. Chen Madeleine C. Mankowski Renata B. Filler Neal G. Ravindra Victor Gasque Fernando J. de Miguel Ajinkya Patil Huacui Chen Craig B. Wilen 《Cell》2021,184(1):76-91.e13
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Xiuyun Ye Shigeru Yoshida T. B. Ng 《The international journal of biochemistry & cell biology》2000,32(11-12)
A mild and rapid method is described for isolating various milk proteins from bovine rennet whey. β-Lactoglobulin from bovine rennet whey was easily adsorbed on and desorbed from a weak anion exchanger, diethylaminoethyl-Toyopearl. However, α-lactalbumin could not be adsorbed onto the resin. α-Lactalbumin and β-lactoglobulin from rennet whey could also be adsorbed and separated using a strong anion exchanger, quaternary aminoethyl-Toyopearl. The rennet whey was passed through a strong cation exchanger, sulphopropyl-Toyopearl, to separate lactoperoxidase and lactoferrin. α-Lactalbumin and β-lactoglobulin were adsorbed onto quaternary aminoethyl-Toyopearl. α-Lactalbumin was eluted using a linear (0–0.15 M) concentration gradient of NaCl in 0.05 M Tris–HCl buffer (pH 8.5). Subsequently, β-lactoglobulin B and β-lactoglobulin A were eluted from the column with 0.05 M Tris–HCl (pH 6.8), using a linear (0.1–0.25 M) concentration gradient of NaCl. The yields were 1260 mg α-lactalbumin, 1290 mg β-lactoglobulin B and 2280 mg β-lactoglobulin A from 1 l rennet whey. 相似文献
6.
Hanna ten Brink Renske E. Onstein André M. de Roos 《Evolution; international journal of organic evolution》2020,74(8):1826-1850
Although metamorphosis is widespread in the animal kingdom, several species have evolved life-cycle modifications to avoid complete metamorphosis. Some species, for example, many salamanders and newts, have deleted the adult stage via a process called paedomorphosis. Others, for example, some frog species and marine invertebrates, no longer have a distinct larval stage and reach maturation via direct development. Here we study which ecological conditions can lead to the loss of metamorphosis via the evolution of direct development. To do so, we use size-structured consumer-resource models in conjunction with the adaptive-dynamics approach. In case the larval habitat deteriorates, individuals will produce larger offspring and in concert accelerate metamorphosis. Although this leads to the evolutionary transition from metamorphosis to direct development when the adult habitat is highly favorable, the population will go extinct in case the adult habitat does not provide sufficient food to escape metamorphosis. With a phylogenetic approach we furthermore show that among amphibians the transition of metamorphosis to direct development is indeed, in line with model predictions, conditional on and preceded by the evolution of larger egg sizes. 相似文献
7.
S. C. Ng A. H. Sathananthan P. C. Wong S. S. Ratnam J. Ho H. Mok M. N. Lee 《Molecular reproduction and development》1988,19(3):253-263
Previous studies by a French group (Fertil Steril 44:645–651, 1985) have shown that two-to eight-cell human embryos can survive slow freeze-thawing with propanediol in a biological freezer. These embryos were assessed for morphological appearance by phase-contrast microscopy. We assessed the structure of 25 frozen-thawed one- to 12-cell embryos, obtained from our in vitro fertilization (IVF) and GIFT programmes, by phase-contrast and electron microscopy, using the same method of cryopreservation. One-fourth of the embryos examined had all cells intact, and more than one-half the embryos had over 50% of their cells well preserved. Some of these embryos had unequal blastomeres and cytoplasmic fragments. Ultrastructural assessment revealed good preservation of fine structure in the intact blastomeres of all embryos and maintenance of cell-to-cell contacts. Most cytoplasmic organelles, cell membranes, and nuclei were well preserved compared to nonfrozen controls. The cells that were cryoinjured showed varying degrees of disorganization of the cell membrane, cytosol, and cellular membranes, including swelling and disruption of the nuclear envelope. Disruption of the zona was somewhat rare. Small cytoplasmic fragments were less prone to cryoinjury than blastomeres. The use of propanediol for embryo cryopreservation seems to be feasible; frozen embryos with more than 50% cells intact have produced 10 pregnancies after embryo transfer (Fertil Steril 46:268–272, 1986). Replacement of 17 frozen embryos in seven patients has resulted in a twin pregnancy in Singapore. However, the effects of freezing on the mitotic spindles of embryonic cells need to be investigated further. 相似文献
8.
Effect of Phosphate on the Corrosion of Carbon Steel and on the Composition of Corrosion Products in Two-Stage Continuous Cultures of Desulfovibrio desulfuricans 总被引:9,自引:4,他引:5
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Paul J. Weimer Margaret J. Van Kavelaar Charles B. Michel Thomas K. Ng 《Applied microbiology》1988,54(2):386-396
A field isolate of Desulfovibrio desulfuricans was grown in defined medium in a two-stage continuous culture apparatus with different concentrations of phosphate in the feed medium. The first state (V1) was operated as a conventional chemostat (D = 0.045 h−1) that was limited in energy source (lactate) or phosphate. The second stage (V2) received effluent from V1 but no additional nutrients, and contained a healthy population of transiently starved or resting cells. An increase in the concentration of phosphate in the medium fed to V1 resulted in increased corrosion rates of carbon steel in both V1 and V2. Despite the more rapid corrosion observed in growing cultures relative to that in resting cultures, corrosion products that were isolated under strictly anaerobic conditions from the two culture modes had similar bulk compositions which varied with the phosphate content of the medium. Crystalline mackinawite (Fe9S8), vivianite [Fe3(PO4)2 · 8H2O], and goethite [FeO(OH)] were detected in amounts which varied with the culture conditions. Chemical analyses indicated that the S in the corrosion product was almost exclusively in the form of sulfides, while the P was present both as phosphate and as unidentified components, possibly reduced P species. Some differential localization of S and P was observed in intact corrosion products. Cells from lactate-limited, but not from phosphate-limited, cultures contained intracellular granules that were enriched in P and Fe. The results are discussed in terms of several proposed mechanisms of microbiologically influenced corrosion. 相似文献
9.
A Chinese hamster ovary auxotroph requiring glycine + adenosine + thymidine (CHO AUXB1) was shown by us previously to lack several folylpolyglutamate synthetase (FPGS) type activities. Two revertants of AUXB1 (one spontaneous and one Pt(S04)2 induced) have been isolated and found to contain altered forms of this enzyme. The revertant enzymes are more sensitive to heat inactivation (37 °C, pH 7.4 or 9.0) than the parent CHO enzyme. Increased sensitivity of revertant FPGS is observed irrespective of whether one assays the specific catalysis of radioactive tetrahydropteroyldi- or tetraglutamate synthesis. ATP and MgCl2 protect both revertant and parent CHO FPGS against rapid heat denaturation at pH 9.0, but not at pH 7.4. A genetically related auxotroph (CHO AUXB3) contains one-fifth the parent amount of FPGS. AUXB3 FPGS shows a normal sensitivity to 37 °C heat inactivation, but it has an altered substrate saturation and specificity pattern when assayed for tetrahydropteroyldi[U-14C]glutamate synthesis. Also, unlike the FPGS from parent CHO and a genetically unrelated mutant requiring only glycine (CHO AUXB2), the AUXB3 enzyme specifically lacks tetrahydropteroyltetra[U-14C]glutamate synthetase activity. These findings and polyethylene glycol fusion data with AUXB2 indicate that AUXB1 and AUXB3 each carry a mutation in the structural gene for a CHO FPGS that catalyzes tetrahydropteroyldi- as well as tetraglutamate formation. The altered form of FPGS in AUXB3 is responsible for its glycine + adenosine auxotrophy under standard culture conditions. 相似文献
10.
Quantum yields (φ) for the aerobic photolysis of 5′-deoxyadenosylcobalamin (dAB12), methylcobalamin (MeB12), propylcobalamin (PrB12), and ethylcobalamin (EtB12) were determined as a function of the irradiation wavelength. φ Determinations were made for both the base-on and base-off forms of each compound (except base-off dAB12) at incident wavelengths from 250 nm to 570 nm. As a rule, the φs were high (0.1–0.5) and they varied significantly with respect to the irradiation wavelength. In general, each alkylcobalamin at pH 7.0 displayed a quantum yield spectrum distinct from its base-off form at pH 1.0. Across most of the spectrum, the φs of the base-off form were appreciably smaller than the base-on φs of the same compound. An exception to this generality was MeB12 for which the φs at pH 1.0 were about the same as, or slightly greater above 450 nm than those at pH 7.0. At pH 7.0 and in the visible region the trend of the φs was dAB12 < MeB12 < PrB12 < EtB12. Under neutral conditions each compound showed a broad quantum yield peak in the 450–470 nm region.From the quantum yield and absorption spectra, photolysis spectra were calculated for 5.0 × 10?5m solutions of each compound. The light-action spectra accurately give the relative rates/μ Einstein that these solutions photolyze at each wavelength. Thus, for example, MeB12 photolyzed faster at pH 7.0 versus pH 1.0 in 510 nm light, but it photolyzed slower at pH 7.0 versus pH 1.0 in 450 nm light. Solutions of each compound photolyzed faster in the ultraviolet region as opposed to the visible (e.g., 310 nm versus 510 nm).Our findings show that the previously reported photolysis rates estimated by others with tungsten lamps provide no valid information about the intrinsic photolability of various alkyl-cobalt bonds. This also applies to the relative white-light photolysis rates reported for the base-on versus the base-off form of MeB12. All such relative rates are artifacts which represent only the extent of overlap between the true action spectrum and the light emission spectrum of an incandescent lamp. 相似文献