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排序方式: 共有1866条查询结果,搜索用时 15 毫秒
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Gaute W. Seljestad María Quintela Ellika Faust Kim T. Halvorsen Franois Besnier Eeva Jansson Geir Dahle Halvor Knutsen Carl Andr Arild Folkvord Kevin A. Glover 《Ecology and evolution》2020,10(12):6120-6135
Capture and long‐distance translocation of cleaner fish to control lice infestations on marine salmonid farms has the potential to influence wild populations via overexploitation in source regions, and introgression in recipient regions. Knowledge of population genetic structure is therefore required. We studied the genetic structure of ballan wrasse, a phenotypically diverse and extensively used cleaner fish, from 18 locations in Norway and Sweden, and from Galicia, Spain, using 82 SNP markers. We detected two very distinct genetic groups in Scandinavia, northwestern and southeastern. These groups were split by a stretch of sandy beaches in southwest Norway, representing a habitat discontinuity for this rocky shore associated benthic egg‐laying species. Wrasse from Galicia were highly differentiated from all Scandinavian locations, but more similar to northwestern than southeastern locations. Distinct genetic differences were observed between sympatric spotty and plain phenotypes in Galicia, but not in Scandinavia. The mechanisms underlying the geographic patterns between phenotypes are discussed, but not identified. We conclude that extensive aquaculture‐mediated translocation of ballan wrasse from Sweden and southern Norway to western and middle Norway has the potential to mix genetically distinct populations. These results question the sustainability of the current cleaner fish practice. 相似文献
3.
Ten hypothyroid patients with Hashimoto''s thyroiditis were treated with methimazole 30 mg in addition to thyroxine 0.15 mg daily. Another 10 hypothyroid patients with Hashimoto''s thyroiditis were given thyroxine 0.15 mg alone. After 22 weeks of treatment significant decreases in thyroid microsomal autoantibody titres were observed in both groups (p less than 0.01). There was no difference in the mean change in titre between the two groups. When the patients treated with methimazole were subsequently given thyroxine 0.15 mg alone for a further 22 weeks no additional change in titre was observed. The data suggest that thyroxine, by normalising serum thyroid stimulating hormone concentrations, may reduce the autoantigenic properties of the thyrocytes with a subsequent decrease in autoantibody titres. 相似文献
4.
Anaerobic dissolution of iron-phosphorus complexes in sediment due to the activity of nitrate-reducing bacteria 总被引:5,自引:0,他引:5
Mats Jansson 《Microbial ecology》1987,14(1):81-89
Nitrate-reducing bacteria (Pseudomonas fluorescens andAlcaligenes sp.) as well as extracellular compounds from these bacteria increased the dissolution rate of iron and phosphorus sorbed to iron precipitates during anaerobic, nitrate-free conditions in experimental sediment-water systems. It is suggested that the influence of the bacteria is due to enzymatic catalyzation of chemical iron reduction. 相似文献
5.
N. Marban-Mendoza A. Jeyaprakash H.-B. Jansson R. A. Damon Jr. B. M. Zuckerman 《Journal of nematology》1987,19(3):331-335
Significant control of tomato root knot was achieved by applications of the lectins Concanavalin A (Con A) and Limax flavus agglutinin in greenhouse, growth chamber, and microplot trials. Four consecutive weekly applications at lower concentrations of Con A yielded better control than single applications at a higher total concentration. The present state of knowledge on binding of Con A to soil nematodes and the in vitro effect of this lectin in chemotactic behavior are discussed. The mode of action of Con A on root-knot control is unknown. 相似文献
6.
A. Tyagi J. Hermans J. Steppuhn Ch. Jansson F. Vater R. G. Herrmann 《Molecular & general genetics : MGG》1987,207(2-3):288-293
Summary Several cDNA clones encoding the 33 kDa protein associated with the photosynthetic water oxidation activity of spinach were sequenced. A 1208 bp insert of one of the clones encodes the entire 331 amino acid residues of the precursor protein including 84 amino acids (8.5 kDa) of the amino-terminal transit peptide, 49 bp of the 5 and 111 bp of the 3 untranslated segment of the mRNA. The 3 poly(A) tail starts 19 bp downstream from a putative polyadenylation signal, TATAAA. The hydrophilic mature protein consists of 247 amino acid residues corresponding to an Mr of 26.5 kDa, which is 6.5 kDa smaller than the value determined by SDS-polyacrylamide gel electrophoresis (33–34 kDa), and shows a certain degree of conservation with the putative Mn-complexing active sites of bacterial Mn-dependent superoxide dismutases. The anatomy of the unusually long transit sequence is discussed with regard to current concepts of protein import into and protein routein within the organelle. 相似文献
7.
Construction of an Obligate Photoheterotrophic Mutant of the Cyanobacterium Synechocystis 6803 : Inactivation of the psbA Gene Family 总被引:14,自引:0,他引:14 下载免费PDF全文
psbA in Synechocystis 6803 was found to belong to a small multigene family with three copies. The psbA gene family was inactivated in vitro by insertation of bacterial drug resistance markers. Inactivation of all three genes resulted in a transformant that is unable to grow photosynthetically but can be cultured photoheterotrophically. This mutant lacks oxygen evolving capacity but retains photosystem I activity. Room temperature measurements of chlorophyll a fluorescence induction demonstrated that the transformant exhibits a high fluorescence yield with little or no variable fluorescence. Immunoblot analyses showed complete loss of the psbA gene product (the DI polypeptide) from thylakoid membranes in the transformant. However, the extrinsic 33 kilodalton polypeptide of the water-splitting complex of photosystem II, is still present. The results indicate that assembly of a partial photosystem II complex may occur even in the absence of the intrinsic D1 polypeptide, a protein implicated as a crucial component of the photosystem II reaction center. 相似文献
8.
A genetic engineering approach is described for directed immobilization of IgG-binding receptors to a thiol-containing matrix using a single cysteine residue. The cysteine residue is introduced into the C-terminal part of receptors based on staphylococcal protein A. Receptors containing one, two or five IgG-binding domains were produced in Escherichia coli and subsequently immobilized on thiopropyl-Sepharose. A high amount, 5 mumol/ml gel (45 mg/ml), of recombinant receptor could be rapidly immobilized to the solid support and both the gel and the immobilized receptor could be regenerated by reduction and oxidation reactions. The gel was used for affinity purification of human IgG and analysis of IgG-binding capacity at different amounts of immobilized recombinant protein show the same maximal IgG-binding capacity (20-25 mg/ml) for all three immobilized receptors. However, at low substitution grade of receptors, the immobilized receptor molecules were shown to bind one (Z-Cys) and two (ZZ-Cys) IgG molecules, respectively. These results demonstrate that the immobilized protein molecules are in a functionally active form and that a two-domain receptor can bind two molecules of IgG without steric hindrance. Interestingly, the five-domain receptor (ZV-Cys), with a structure similar to native protein A, can only bind approximately two IgG molecules, despite the five-domain structure of the molecule. 相似文献
9.
Effects of training at simulated altitude on performance and muscle metabolic capacity in competitive road cyclists 总被引:1,自引:0,他引:1
Nicolas Terrados Jan Melichna Christer Sylvén Eva Jansson Lennart Kaijser 《European journal of applied physiology and occupational physiology》1988,57(2):203-209
Differences between the effects of training at sea level and at simulated altitude on performance and muscle structural and biochemical properties were investigated in 8 competitive cyclists who trained for 3-4 weeks, 4-5 sessions/week, each session consisting of cycling for 60-90 min continuously and 45-60 min intermittently. Four subjects, the altitude group (AG), trained in a hypobaric chamber (574 torr = 2300 m above sea level), and the other four at sea level (SLG). Before and after training work capacity was tested both at simulated altitude (574 torr) and at sea level, by an incremental cycle ergometer test until exhaustion. Work capacity was expressed as total amount of work performed. Venous blood samples were taken during the tests. Leg muscle biopsies were taken at rest before and after the training period. AG exhibited an increase of 33% in both sea level and altitude performance, while SLG increased 22% at sea level and 14% at altitude. Blood lactate concentration at a given submaximal load at altitude was significantly more reduced by training in AG than SLG. Muscle phosphofructokinase (PFK) activity decreased with training in AG but increased in SLG. All AG subjects showed increases in capillary density. In conclusion, work capacity at altitude was increased more by training at altitude than at sea level. Work capacity at sea level was at least as much improved by altitude as by sea level training. The improved work capacity by training at altitude was paralleled by decreased exercise blood lactate concentration, increased capillarization and decreased glycolytic capacity in leg muscle. 相似文献
10.
Stefan Jansson Eran Pichersky Roberto Bassi Beverley R. Green Masahiko Ikeuchi Anastasios Melis David J. Simpson Michael Spangfort L. Andrew Staehelin J. Philip Thornber 《Plant Molecular Biology Reporter》1992,10(3):242-253
We propose a nomenclature for the genes encoding the chlorophylla/b-binding proteins of the light-harvesting complexes of photosystem I and II. The genes encoding LHC I and LHC II polypeptides
are namedLhca1 throughLhca4 andLhcb1 throughLhcb6, respectively. The proposal follows the general format recommended by the Commision on Plant Gene Nomenclature. We also present
a table for the conversion of old gene names to the new nomenclature. 相似文献