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53.
Production and characterization of recombinant human neutrophil chemotactic factor 总被引:15,自引:0,他引:15
R Furuta J Yamagishi H Kotani F Sakamoto T Fukui Y Matsui Y Sohmura M Yamada T Yoshimura C G Larsen 《Journal of biochemistry》1989,106(3):436-441
A putative mature human neutrophil chemotactic factor (NCF) corresponding to the C-terminal 72 amino acids of its precursor was directly produced in Escherichia coli by recombinant DNA technology. Human NCF was present in both the soluble and insoluble protein fractions of the homogenate of host cells, and it was partially purified as a water-soluble polypeptide from both fractions, separately. The partially purified NCF preparation was highly purified to an endotoxin-free homogeneous polypeptide by means of CM-Sepharose CL-6B column chromatography and gel filtration on Toyopearl HW-55. No difference between the human NCF preparations purified from both starting materials could be found concerning purity, primary structure, solubility, molecular weight, and chemotactic activity for human neutrophils. The amino acid sequence of recombinant human NCF was identical to the sequence deduced from the cDNA sequence. A methionine residue due to the translation initiation codon was removed. Recombinant human NCF was found to be biologically active and to exhibit chemotactic activity for human neutrophils in vitro and cause a neutrophil infiltration in vivo in mice. 相似文献
54.
Cumulus cells in the mammalian ovary are normally connected to each other and to their enclosed oocyte by an extensive network of gap junctions (GJs). We have shown that the loss of cumulus cell GJs is correlated temporally with meiotic resumption in the intact preovulatory rat follicle (Larsen et al., 1986). Here we describe morphological changes in GJ particle packing patterns (PPPs) that occur prior to GJ loss and meiotic resumption in hormonally stimulated rat cumulus-oocyte complexes (COCs). In the PMSG-primed rat, 89% of the cumulus cell GJ area detected by freeze-fracture electron microscopy consists of tightly packed junctional particles: 4% exhibit loose PPPs of randomly dispersed particles; and 7% contain a mixture of both tight and loose PPPs. One to 2 hr after stimulation with hCG, the area of GJs containing tight PPPs drops by 50%-60%, while junctions exhibiting loosely organized and mixed patterns increase concomitantly. These shifts in PPPs are accompanied by the appearance of unusual particle-free areas of puckered or ruffled nonjunctional membrane at the GJ periphery. Cumulus cell GJs from isolated COCs incubated in FSH-containing medium demonstrate a similar shift in PPPs prior to meiotic resumption. The appearance of fusing areas of particle-free nonjunctional membrane at the GJ periphery in vitro is correlated with GJ loss and is not seen in COCs treated with dihydrocytochalasin B to inhibit endocytotic removal of cumulus GJs. The structural and temporal nature of these morphological observations supports the hypothesis that interruption of junctional communication plays a role in meiotic maturation of the preovulatory oocyte. 相似文献
55.
Bull breeding soundness parameters, semen characteristics and sexual behavior were evaluated for effects on reproductive performance in single-sire beef herds. A total of 155 cow herds (Angus, 50 herds; Hereford, 40 herds; Brahman, 46 herds; and Senepol, 19 herds) bred to bulls of the same breed were observed for 8 yr. All bulls produced adequate quality semen and had scrotal circumference (SC) >/= 30 cm. Reproductive performance was evaluated by the conception rate (CON), conception rate during the first 21 d of the breeding season (21dCON), mean calving date (MCD), and mean calving date of the first half of the herd to calve (HHCD). Correlations were determined between breeding soundness parameters and reproductive performance for all bulls combined, by breed, and by age. The Cp statistic was used to select models for the effects of parameters on CON, 21dCON, MCD and HHCD. Breeding season length and breed had significant effects. The percentages of normal cells, proximal droplets, detached heads and the semen score (motility plus percentage of normal cells) had a significant effect on CON when all bulls were considered. After the effect of season was deleted, the most significant parameter affecting CON in the Brahman was the percentage of detached sperm heads. In the Angus, motility was significantly correlated with all reproductive performance indices. In the Hereford, breeding soundness examination score (BSE) was positively correlated with 21dCON. 相似文献
56.
J. Wolstrup P. Nansen J. Gronvold S. A. Henriksen M. Larsen 《Journal of nematology》1996,28(2):129-132
In a series of laboratory and field experiments where the nematophagous fungus Arthrobotrys oligospora was mixed directly with feces it has been demonstrated that it is possible to use nematophagous fungi for biological control of animal parasitic nematodes. A procedure used for selection of nematophagous fungi that can pass the digestive tract of ruminants, horses, and pigs is described. The selected fungus, Duddingtonia flagrans, has been used in further field experiments, and the results have confirmed that by the addition of D. flagrans to feed supplement it is possible to reduce the parasitic burden significantly. 相似文献
57.
Comparison of a commercial biochemical kit and an oligonucleotide probe for identification of environmental isolates of Vibrio vulnificus 总被引:3,自引:0,他引:3
A. DALSGAARD, I. DALSGAARD, L. HØI AND J.L. LARSEN. 1996. Methods for the identification and isolation of environmental isolates of Vibrio vulnificus were evaluated. Alkaline peptone water supplemented with polymyxin B and colistin-polymyxin B-cellobiose agar were employed for the isolation of suspected V. vulnificus from water, sediment and shellfish samples. When comparing the identification of putative V. vulnificus obtained with the API 20E assay and an oligonucleotide probe, 29 API 20E profiles were obtained with only four profiles (representing 20 isolates) reaching the identification threshold of V. vulnificus among a total of 66 isolates hybridizing with the probe. The results indicated that, compared with colony hybridization, the API 20E assay was not adequate for the identification of environmental isolates of V. vulnificus . 相似文献
58.
Kai Larsen 《Nordic Journal of Botany》1996,16(6):636-636
59.
A novel type of DNA-binding protein interacts with a conserved sequence in an early nodulin ENOD12 promoter 总被引:3,自引:0,他引:3
60.
Al-sensitive (als) mutants of Arabidopsis were isolated and characterized with the aim of defining mechanisms of Al toxicity and resistance. Most als mutants selected on the basis of root growth sensitivity to Al were recessive, and together the mutants constituted eight complementation groups. Also, in most als mutants, Al sensitivity appeared to be specific for Al relative to La (another trivalent cation), except als2, which was more sensitive to La than wild type. The tendency of roots on mutant seedlings to accumulate Al was examined by staining with morin and hematoxylin, dyes used to indicate the presence of Al. A significant increase in morin staining was observed in als5, consistent with its increased sensitivity to Al. Unexpectedly, als7 and als4 showed less morin staining, suggesting that the roots on these mutants accumulate less Al than wild type seedlings after exposure to Al-containing solutions. Roots of wild-type seedlings produce callose in response to AlCl3 concentrations that inhibit root growth. Only als5 accumulated more callose than wild type in response to low levels (25 mu M) of AICI3 However, als4 and als7 did not accumulate callose at this AlCl3 concentration even though root growth was significantly inhibited. The lack of callose accumulation in als4 and als7 suggests that there is not an obligatory relationship between callose deposition and Al-induced inhibition of root growth. 相似文献