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31.
Thirty eight symptomatic and two asymptomatic patients seropositive for human immunodeficiency virus type-1 (HIV-1) were treated with a natural human interferon alpha (HuIFN alpha). Patients were given 2 IU/kg HuIFN alpha orally once daily in powdered maltose held in the mouth to promote mucosal absorption. This oral immunomodulating HuIFN alpha therapy resulted in an increase in CD4+ lymphocytes, an increase in weight, and a dramatic alleviation of clinical symptoms related to HIV-1 infection. 相似文献
32.
Fred Stutzenberger 《Applied microbiology and biotechnology》1988,28(4-5):387-393
Summary Protein-extracted lucerne fibre (PELF) was evaluated as a carbon/energy source for cellulase production by Thermomonospora curvata and as a substrate for enzymatic conversion to soluble sugars. In shake cultures grown at 53°C, pH 8, maximal cellulase (50 endoglucanase IU and 0.7 filter paper IU/ml) was attained at a PELF concentration of 1.3% (w/v) in a vitamin-mineral salts medium buffered with 0.05 M concentrations of phosphate and N-2-hydroxyethylpiperazine-N-2-ethanesulfonate. Multiple endoglucanase enzymes were produced. The major form had an apparent molecular weight of 22 000 and K
m
values of 0.23% and 0.56% for carboxymethylcellulose and PELF respectively. NaOH treatment of PELF increased its susceptibility to enzymatic hydrolysis. During enzymatic hydrolysis of NaOH-treated PELF (60°C, pH 6.1, 24h) two-thirds of total fibre carbohydrate was solubilized as cellobiose, melibiose, cellopentaose, cellotetraose, xylose and glucose in descending order of concentration. 相似文献
33.
Servaas Visser Charles J. Slangen Fred A. Exterkate Gerrie J. C. M. de Veer 《Applied microbiology and biotechnology》1988,29(1):61-66
Summary The specificity of a cell wall proteinase (PI) from Streptococcus cremoris strain HP in its action on bovine -casein was determined. To this end an enzymic digest (pH 6.2; 15° C) of -casein was brought to pH 4.6 and the soluble fraction separated by semi-preparative reversed-phase HPLC. Purified peptides were analyzed by amino acid and end-group analysis. Ten chromatographic components were identified, which together accounted for at least seven cleavage sites all being located in the C-terminal fifty-residue part of -casein. In five cases it concerned a Gln-X or X-Gln peptide linkage. The specificity of this proteinase from S. cremoris HP shows similarity to that reported for a cell wall proteinase from S. lactis NCDO 763 in its action on -casein.Presented at the second FEMS Symposium on Lactic Acid Bacteria held in 1987 at Wageningen, Netherlands 相似文献
34.
Adriaan P. de Bruïne Winand N. M. Dinjens Margriet M. J. Pijls Edith P. M. v. d. Linden Mat J. M. Rousch Peter T. Moerkerk Antony F. P. M. de Goeij Fred T. Bosnian 《Virchows Archiv. B, Cell pathology including molecular pathology》1992,62(1):311-320
In colonic neoplasms, endocrine differentiation is encountered not only in carcinoid tumors but also in adenocarcinomas, where
endocrine cells may represent a distinct line of differentiation in the tumor. The significance of endocrine differentiation
in colorectal cancer is not well established, partly because of the paucity of tumor cell lines which can serve as a model
for studying endocrine differentiation. In this report we describe the properties of NCI-H716 cells, a cell line derived from
a poorly differentiated adenocarcinoma of the caecum, under various in vitro conditions and as xenografts in athymic mice.
Phenotypical properties were immunohistochemically assessed using a panel of differentiation related antibodies, and also
by Northern blot analysis and by electron microscopy. Receptors for biogenic amines and peptide hormones were analyzed by
ligand binding assay. These studies show that:
相似文献
1. | NCI-H716 cells can be undifferentiated, or show endocrine, mucin-producing or “amphicrine” properties. |
2. | Endocrine differentiation of NCI-H716 cells preferentially occurs in xenografts in athymic mice, which suggests that mesenchymal elements induce endocrine differentiation. |
3. | NCI-H716 cells express large amounts of high affinity receptors for gastrin, serotonin and somatostatin and these substances can regulate growth. Thus, NCI-H716 cells form a suitable model for the study of endocrine differentiation in intestinal epithelium and of auto- or paracrine growth regulation in intestinal neoplasia. |
35.
Thomas L. Pazdernik Matthew Layton Stanley R. Nelson Fred E. Samson 《Neurochemical research》1992,17(1):11-21
This overview presents data showing that glucose use increases and that excitatory amino acids (i.e., glutamate, aspartate), taurine and ascorbate increase in the extracellular fluid during seizures. During the cellular hyperactive state taurine appears to serve as an osmoregulator and ascorbate may serve as either an antioxidant or as a pro-oxidant. Finally, a unifying hypothesis is given for seizure-induced brain damage. This unifying hypothesis states that during seizures there is a release of excitatory amino acids which act on glutamatergic receptors, increasing neuronal activity and thereby increasing glucose use. This hyperactivity of cells causes an influx, of calcium (i.e. calcium stress) and water movements (i.e., osmotic stress) into the cells that culminate in brain damage mediated by reactive oxygen species.Special issue dedicated to Dr. Frederick E. Samson 相似文献
36.
A hamate and the proximal part of a first metacarpal from the type locality of the Nagri Formation in Pakistan, and attributed to Sivapithecus parvada, are described. In overall proportions, the hamate is rather robust, showing most similarity to that of Gorilla. Unlike extant hominoids it lacks a well-developed hamulus, and its triquetral facet is morphologically dissimilar to that in extant anthropoids. The morphology of the hamate indicates effective weight transmission through the ulnar side of the wrist, limited ulnar deviation and restricted extension in the triquetrohamate joint, and stability of the hamatometacarpal joints. The morphology of the partial first metacarpal is most similar to that of Pan. Previously described postcranial bones of S. parvada indicate that its locomotor behaviour included both quadrupedalism and climbing. This is consistent with the limited evidence of the first metacarpal, whereas the hamate strongly emphasizes the quadrupedal aspect of the locomotor repertoire. 相似文献
37.
Significantly higher numbers of Gram-negative heterotrophic bacteria were present at the air-water interface (neston) of freshwater
lakes than in the bulk water. Neuston bacteria were distinguished as a population distinct from bacteria in the bulk water
by a higher incidence of pigmented colony types and significantly greater levels of multiple resistance to antibiotics and
heavy metals. The incidence of plasmids in 236 neuston and 229 bulk water strains were similar (14 and 16.2%, respectively).
Nine of 168 plasmid-free strains and 2 of 14 plasmid carrying strains, isolated from both bulk water and neuston, acted as
recipients of plasmid R68.45 in plate matings with aPseudomonas aeruginosa donor strain PAO4032 at 21°C, but at frequencies below that of matings with a restriction-minus recipient strain ofP. aeruginosa, strain PAO1168. In a model system composed of nutrient-free synthetic lake water, plasmid R68.45 was shown to transfer betweenP. aeruginosa strains at frequencies between 10−3 and 10−5. Transconjugants were detected about 100 times more frequently at the interface than in the bulk water, which in part reflected
a greater enrichment of the donor at this site. None of the aquatic isolates were able to act as recipients of plasmid R68.45
in this model system with strain PAO4032 as donor. The results suggest that under nutrient deprived conditions, the spread
of plasmid R68.45 and similar plasmids by lateral transfer into this particular aquatic population would be a rare event. 相似文献
38.
Comparative Study of Action of Cell Wall Proteinases from Various Strains of Streptococcus cremoris on Bovine αs1-, β-, and κ-Casein
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Servaas Visser Fred A. Exterkate Charles J. Slangen Gerrie J. C. M. de Veer 《Applied microbiology》1986,52(5):1162-1166
Partially purified cell wall proteinases of eight strains of Streptococcus cremoris were compared in their action on bovine αs1-, β-, and κ-casein, as visualized by starch gel electrophoresis, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and thin-layer chromatography. Characteristic degradation profiles could be distinguished, from which the occurrence of two proteinases, represented by strain HP and strain AM1, was concluded. The action of the HP-type proteinase P1 (also detectable in strains Wg2, C13, and TR) was established by electrophoretic methods to be directed preferentially towards β-casein. The AM1-type proteinase PIII (also detectable in strain SK11) was also able to degrade β-casein, but at the same time split αs1- and κ-casein more extensively than did PI. Strain FD27 exhibited mainly PI activity but also detectable PIII degradation characteristics. The cell wall proteinase preparation of strain E8 showed low PI as well as low PIII activity. All proteinase preparations produced from κ-casein positively charged degradation products with electrophoretic mobilities similar to those of degradation products released by the action of the milk-clotting enzyme chymosin. The differences between PI and PIII in mode of action, as detected by gel electrophoresis and thin-layer chromatography, were reflected by the courses of the initial degradation of methyl-14C-labeled β-casein and by the effect of αs1- plus κ-casein on these degradations. The results are discussed in the light of previous comparative studies of cell wall proteinases in strains of S. cremoris and with respect to the growth of this organism in milk. 相似文献
39.
New Procedure for Extraction of Ammonium from Natural Waters for 15N Isotopic Ratio Determinations
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A new method for extracting ammonium from natural waters for 15N isotopic ratio determination is described. The method employs the conversion of the ammonium nitrogen into indophenol, which is then concentrated onto an octadecylsilane column. The method shows accuracy and precision comparable to those of other methods described in the literature. Some results from field experiments on the Swedish west coast are presented. 相似文献
40.
J M Cummins A D Fleming N Crozet T J Kuehl N S Kosower R Yanagimachi 《The Journal of experimental zoology》1986,237(3):375-382
Living spermatozoa of seven mammalian species were treated with the thiol-alkylating fluorescent labelling compound, monobromobimane (MBBR). MB-labelling alone had no effect on sperm motility, nor on the time course or ability of golden hamster spermatozoa to undergo the acrosome reaction when capacitated in vitro. Exposure of MB-labelled spermatozoa to ultraviolet (UV) light and excitation of the MB fluorochrome resulted in virtually immediate immobilization of the spermatozoa without affecting acrosomal status. UV exposure of unlabelled spermatozoa for up to 30 sec had no effect upon motility. Immobilization of MB-labelled spermatozoa depended on the midpiece being irradiated, as irradiation of the head alone, or of the more distal parts of the principal piece, had little or no effect upon motility. Labelling with MB followed by immobilization of individually selected spermatozoa was most useful for detailing the course and site of occurrence of the acrosome reaction during penetration of the cumulus oophorus by golden hamster spermatozoa in vitro. In these often hyperactivated spermatozoa, precise determination of the acrosomal status could not often otherwise be made due to the difficulty in visualizing the acrosomal region of a vigorously thrashing, hyperactivated spermatozoon. This technique should prove valuable in a variety of studies on sperm motility, capacitation and fertilization, and could also be extended to other cell systems. 相似文献