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排序方式: 共有263条查询结果,搜索用时 15 毫秒
1.
Aino Juslén Juha Pykälä Saija Kuusela Lauri Kaila Jaakko Kullberg Jaakko Mattila Jyrki Muona Sanna Saari Pedro Cardoso 《Biodiversity and Conservation》2016,25(3):569-585
For the first time ever, the International Union for Conservation of Nature Red List Index for habitat types was calculated for an entire country, Finland. The RLIs were based on species threat assessments from 2000 and 2010 and included habitat definitions for all 10,131 species of 12 organism groups. The RLIs were bootstrapped to track statistically significant changes. The RLI changes of species grouped by habitats were negative for all habitat types except for forests and rural biotopes which showed a stable trend. Trends of beetles and true bugs were positive in rural and forest habitats. Other 16 observed trends of species group and habitat combinations were negative. Several trends observed were in accordance with studies focusing on particular taxa and habitats, and drivers for their change. This study demonstrates the usefulness of the RLI as a tool for observing habitat change based on species threat assessment data. 相似文献
2.
O M?kel? P Mattila N Rautonen I Sepp?l? J Eskola H K?yhty 《Journal of immunology (Baltimore, Md. : 1950)》1987,139(6):1999-2004
Antibody responses of young adults to Haemophilus influenzae type b polysaccharide (Hib) or its protein conjugate were studied with special attention to the isotype composition of the antibodies. Three conclusions of interest can be made: 1) Immunoglobulin G (IgG) antibodies in polysaccharide-immunized volunteers displayed the subclass pattern previously found in antibodies to meningococcal type A polysaccharide. IgG1 was the predominant subclass in IgG antibodies of some individuals, IgG2 in others. Still others had the two subclasses in varying but more even proportions. 2) The conjugate vaccine induced a geometric mean response 2 to 3 times higher and an IgG response 4 times higher to Hib than the polysaccharide vaccine. 3) Anti-Hib antibodies induced by the conjugate vaccine still had essentially the same IgG subclass composition as anti-Hib antibodies induced by the polysaccharide. This composition was strikingly different from the composition of the anti-diphtheria toxoid response induced by the same conjugate vaccine. 相似文献
3.
4.
The growth of potential food poisoning organisms on chicken and pork muscle surfaces 总被引:2,自引:2,他引:0
Muscle surfaces of pork were inoculated with a mixture of Yersinia enterocolitica and Staphylococcus aureus , and chicken muscle with Campylobacter jejuni or a mixture of Salmonella typhimurium and Staph. aureus . The surface growth at 20°C was followed microscopically. Organisms grew as discrete colonies bound together by a glycocalyx which differed between bacterial species. On prolonged incubation colonies spread peripherally and tended to coalesce, while still retaining their colony structure. Staphlycoccus aureus colonies were very small and remained so. The glycocalyx was considered critical in maintaining the dense populations of bacteria on the meat surfaces. 相似文献
5.
Fidelity of DNA synthesis by the Thermococcus litoralis DNA polymerase--an extremely heat stable enzyme with proofreading activity 总被引:15,自引:2,他引:13 下载免费PDF全文
We demonstrate that the DNA polymerase isolated from Thermococcus litoralis (VentTM DNA polymerase) is the first thermostable DNA polymerase reported having a 3'----5' proofreading exonuclease activity. This facilitates a highly accurate DNA synthesis in vitro by the polymerase. Mutational frequencies observed in the base substitution fidelity assays were in the range of 30 x 10(-6). These values were 5-10 times lower compared to other thermostable DNA polymerases lacking the proofreading activity. All classes of DNA polymerase errors (transitions, transversions, frameshift mutations) were assayed using the forward mutational assay (1). The mutation frequencies of Thermococcus litoralis DNA polymerase varied between 15-35 x 10(-4) being 2-4 times lower than the respective values obtained using enzymes without proofreading activity. We also noticed that the fidelity of the DNA polymerase from Thermococcus litoralis responds to changes in dNTP concentration, units of enzyme used per one reaction and the concentration of MgSO4 relative to the total concentration of dNTPs present in the reaction. The high fidelity DNA synthesis in vitro by Thermococcus litoralis DNA polymerase provides good possibilities for maintaining the genetic information of original target DNA sequences intact in the DNA amplification applications. 相似文献
6.
Mauri J. Mattila 《Human genetics》1970,9(3):212-214
7.
M L Majuri P Mattila R Renkonen 《Biochemical and biophysical research communications》1992,182(3):1376-1382
E-selectin (previously known as ELAM-1) is one of the adhesion molecules expressed on activated endothelium. Here we show that HL-60 cells express sialyl-Le(x), but not Sialyl-Le(a) on their surface, a colon carcinoma cell line COLO 205 express both these epitopes and another colon carcinoma COLO 320 does not express either one of them. HL-60 and COLO 205 cell adhere strongly to E-selectin coated microwells, whereas COLO 320 does not adhere at all to E-selectin. Finally we provide evidence that monoclonal anti-sialyl-Le(x) can abolish part of the adherence of HL-60 cells to recombinant E-selectin. The adherence of COLO 205 cells can be decreased by either monoclonal anti-sialyl-Le(a) or anti-sialyl-Le(x) antibodies. These results indicate that cell-associated sialylated carbohydrate moieties can act as ligands for recombinant E-selectin. 相似文献
8.
L C Sellin K Mattila A Annila J J Schmidt J J McArdle M Hyv?nen T T Rantala T Kivist? 《Biophysical journal》1996,70(1):3-13
The 22-residue toxic peptide (WTX1) from the venom of the Southeast Asian snake Trimeresurus wagleri has multiple sites of action, but its lethal effect has been attributed to blocking the postsynaptic acetylcholine receptor at the neuromuscular junction. The 3-dimensional structure of WTX1 was studied using 2-dimensional nuclear magnetic resonance spectroscopy, circular dichroism, and computer simulations. In aqueous solution, WTX1 was shown to have extended and flexible "tails" defined by a short, rigid disulfide-bonded loop. The flexible regions can undergo structural rearrangement when moved from an aqueous to a less polar environment and may contribute to its effectiveness at different receptor sites. By substituting Gly or Phe for His at position 10, significant effects on the disulfide bond formation and, thereby, the activity of the peptide were observed. These results suggest that even subtle differences in single residues can have profound effects on the dynamics of folding, disulfide bond formation, and activity of this toxic peptide. 相似文献
9.
M. Peltomaa K. Mattila J. Wolf M. Hyvönen-Dabek 《Biological trace element research》1992,34(3):249-255
The trace elements of both calcified atherosclerotic plaques and plaque-free vessel walls of the carotid bifurcation from
31 autopsies were investigated using the proton-induced X-ray emission (PIXE) method. The trace elements studied were phosphorus
(P), calcium (Ca), chrome (Cr), iron (Fe), copper (Cu), zinc (Zn), lead (Pb), selenium (Se), bromine (Br), strontium (Sr),
and rubidium (Rb). All samples contained Fe and Zn. Mercury (Hg) was not detected in any of the samples studied. All plaque-free
samples contained Cu and almost all Br and Ca, none Sr. All calcified atherosclerotic plaques contained Ca and almost all
Br and Sr. The relative levels of Ca were higher in the calcified plaques than in the plaque-free vessel walls. The relative
value of Ca in calcified and uncalcified samples was greatest in the group who had died because of cardiovascular disorders
and smallest in the group who had died from other causes. There was a strong positive correlation between the Ca and Sr of
the plaque samples and between the P and Br of the plaque-free samples. 相似文献
10.
Semliki Forest virus was grown in BHK cells and labeled in vivo with radioactive monosaccharides. Pronase digests of the virus chromatographed on Bio-Gel P6 revealed glycopeptides of A-type and B-type. (For the nomenclature see Johnson, J. and Clamp, J.R. (1971) Biochem. J. 123, 739-745.) The former was labeled with [3H]fucose, [3H]galactose, [3H]mannose and [14C]glucosamine, the latter only with [3H]mannose and [14C]glucosamine. The three envelope glycoproteins E1, E2 and E3 were isolated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and subjected to pronase digestion. The glycoproteins E1 and E3 revealed glycopeptides of A-type. E2 revealed glycopeptides of B-type. E2 yielded additionally a glycopeptide (Mr3100) which was heavily labeled from [3H]galactose, but only marginally from [14C]glucosamine, [3H]fucose and [3H]mannose. Whether this glycopeptide belongs to the A-type or not remains uncertain. The apparent molecular weights of the A-type units measured by gel filtration were 3400 in E1 and 4000 in E3; the B-type unit of E2 had an apparent molecular weight of 2000. Combined with the findings of our earlier chemical analysis these data suggest that E1 and E3 contain on the average one A-type unit; E2 probably contains one 3100 dalton unit plus one or two B-type units. 相似文献