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71.
G. Guillen M. J. Leal A. Alvarez M. Delgado R. Silva L. Herrera 《Engineering in Life Science》1995,15(1):97-106
The 5C outer membrane protein, one of the N. meningitidis class 5 proteins, was preferably expressed in bacteria isolated from the nasopharynx and its role in adhering to the mucosal cells and invading them as well as the development of anti-5C antibodies in healthy carriers was demonstrated. Anti-5C monoclonal antibodies are bactericidal in the presence of the human complement. The immunodominant region of the 5C protein is highly conserved among the different strains of N. meningitidis, and the opc gene, which encodes the protein, does not seem to show antigenic variations. Here the isolation of the opc gene from the Cuban strain B:4:P1.15 by PCR (Polymerase Chain Reaction) is presented. Under the regulation of the tryptophan promoter, the gene was cloned and sequenced in E. coli with a high level of expression and fused to the amino-terminal end of the interleukin-2 gene. In the dot-blot experiments, the presence of the gene in those strains which did not express the protein in the whole cell ELISA was also detectable. 相似文献
72.
Akira Akabayashi C.T.B.V. Zaia James I. Koenig Steven M. Gabriel Ivan Silva Sarah F. Leibowitz 《Peptides》1994,15(8):1437-1444
The peptide galanin (GAL), when injected into the rat hypothalamus, is known to stimulate feeding behavior and affect the secretion of various hormones, including insulin and the adrenal steroid, corticosterone. To determine whether endogenous peptide levels shift in relation to natural rhythms of feeding and circulating hormone levels, rats were sacrificed at different times of the light/dark cycle, and their GAL levels were measured, via radioimmunoassay, in medial hypothalamic dissections and micropunched hypothalamic areas. The results suggest the existence of two distinct diurnal rhythms for hypothalamic GAL. One rhythm, detected exclusively in the area of the SCN, is characterized by bimodal peaks of GAL, threefold higher than basal peptide levels, around the onset of the dark and light periods. The second rhythm shows a single peak of GAL towards the middle of the nocturnal feeding cycle, specifically between the third and sixth hour. This latter rhythm is evident in the dorsal region of the medial hypothalamus, localized specifically to the lateral portion of the PVN. Moreover, it is inversely related to circulating insulin but unrelated to the adrenal steroids, suggesting a possible association between this pancreatic hormone and GAL in the PVN. 相似文献
73.
Theresa A. Grebe William K. Seltzer Jean DeMarchi Dinithi K. Silva W. W. Doane David Gozal S. F. Richter C. Michael Bowman R. A. Norman Susan N. Rhodes Lucy S. Hernried Shirley Murphy Ivan R. Harwood Frank J. Accurso Karen D. Jain 《American journal of human genetics》1994,54(3):443-446
We have performed molecular genetic analyses of Hispanic individuals with cystic fibrosis (CF) in the southwestern United States. Of 129 CF chromosomes analyzed, only 46% (59/129) carry ΔF508. The G542X mutation was found on 5% (7/129) of CF chromosomes. The 3849+10kbC→T mutation, detected primarily in Ashkenazi Jews, was present on 2% (3/129). R1162X and R334W, mutations identified in Spain and Italy, each occurred on 1.6% (2/129) of CF chromosomes. W1282X and R553X were each detected once. G551D and N1303K were not found. Overall, screening for 22 or more mutations resulted in detection of only 58% of CF transmembrane conductance regulator gene mutations among Hispanic individuals. Analysis of KM19/XV2c haplotypes revealed an unusual distribution. Although the majority of ΔF508 mutations are on chromosomes of B haplotypes, the other CF mutations are on A and C haplotypes at higher-than-expected frequencies. These genetic analyses demonstrate significant differences between Hispanic individuals with CF and those of the general North American population. Assessment of carrier/affected risk in Hispanic CF individuals cannot, therefore, be based on the mutation frequencies found through studies of the general population but must be adjusted to better reflect the genetic makeup of this ethnic group. Further studies are necessary to identify the causative mutation(s) in this population and to better delineate genotype/phenotype correlations. These will enable counselors to provide more accurate genetic counseling. 相似文献
74.
dos Santos Silva Edinaldo N. Kakkassery Francy K. Maas Sibylle Dumont Henri J. 《Hydrobiologia》1994,288(2):119-128
Calanoid copepods, belonging to the new genus and species Keraladiaptomus rangareddyi, were collected from temporary ponds in Kerala State, India. The new genus belongs to the family Diaptomidae, subfamily Diaptominae. It is described in detail and its affinity to the related genera, Arctodiaptomus Kiefer, 1932 and Eodiaptomus Kiefer, 1932, discussed. 相似文献
75.
Reis M. F. Machado A. A. S. C. Abdulla M. Canário J. Silva J. C. 《Biological trace element research》1994,43(1):585-596
Biological Trace Element Research - To make the best use of time and facilities, a neutron activation system, fully automatic, including spectrum and data processing, to be used with short-lived... 相似文献
76.
Nostoc sp. was cultivated in an air-lift reactor with continuous recirculation of the head gas phase that aerated and agitated the cyanobacterial suspension at regulated flow rates. The supply of inorganic carbon for growth was coupled with pH control, in the range of 7.7 to 8.1, by intermittent sparging of CO2-head gas mixtures. The formation of irregular bubbles with swirling motion at the photostage of the reactor promoted efficient CO2 transference in dense populations of Nostoc sp. (1.1 g/l) when bubbling at flow rates of 10 l/min. Biomass productivity was almost six-fold higher in the photoreactor (16.4 mg/l.h) than in a conventional system (2.8 mg/l.h). The exponential growth phase of cultures in the photoreactor amounted to 60% of the total growth period.The authors are with the Laboratorio de Alimentos, Area Microbiologia, Facultad de Quimica Bioquimica y Farmacia, Universidad Nacional de San Luis, Chacabuco y Pedernera, 5700 San Luis, Argentina 相似文献
77.
78.
Zampronio AR Melo MC Silva CA Pelá IR Hopkins SJ Souza GE 《Mediators of inflammation》1994,3(5):365-373
The aim of this study was to investigate the pyrogenic activity of factor(s) released by rat peritoneal macrophages following a brief stimulation with LPS. The effect of this factor on the number of circulating leukocytes and serum Fe, Cu and Zn levels, was also evaluated. The possibility that the content of interleukin (IL)-1beta, IL-6 and tumour necrosis factor (TNF) in the supernatant could explain the observations was investigated. Supernatant produced over a period of 1 h by peritoneal macrophages, following a 30 min incubation with LPS at 37 degrees C, was ultrafiltered through a 10 000 MW cut-off Amicon membrane, sterilized, and concentrated 2.5, 5, 10 and 20 times. The intravenous (i.v.) injection of this supernatant induced a concentration-dependent fever in rats with a maximal response at 2 h. The pyrogenic activity was produced by macrophages elicited with thioglycollate and by resident cells. The supernatants also induced neutrophilia and reduction in Fe and Zn 6 h after the injection. Absence of activity in boiled supernatants, or supernatants from macrophages incubated at 4 degrees C with LPS, indicates that LPS was not responsible for the activity. In vitro treatment with indomethacin (Indo), dexamethasone (Dex), or cycloheximide (Chx) did not modify the release of pyrogenic activity into the supernatant or its effects on the reduction in serum metal levels. Although Chx abolished the production of mediator(s) inducing neutrophilia, and Dex reduced the induction of IL-1beta, TNF and IL-6, injection of the highest concentration of these cytokines detected in the supernatants did not induce fever. In vivo treatment with Dex, but not Indo, abolished the fever induced by the supernatant. These results suggest that macrophages contain pre-formed pyrogenic mediator(s), not related to IL-1beta, IL-6 or TNF, that acts indirectly and independently of prostaglandtn. It also seems likely that the pyrogenic activity is related to the factor responsible for the reduction of serum Fe and Zn levels, but not the neutrophilia. 相似文献
79.
80.
Hydraulic properties of sphagnum peat moss and tuff (scoria) and their potential effects on water availability 总被引:2,自引:0,他引:2
The importance of macrostructure to root growth of ryegrass (L. perenne) seedlings sown on the soil surface was studied in two soils in which the macrostructure had resulted mainly from root growth
and macro-faunal activity. Sets of paired soil cores were used, one of each pair undisturbed and the other ground and repacked
to the field bulk density.
Undisturbed and repacked soils were first compared at equal water potentials in the range −1.9 to −300 kPa. At equal water
potential, the undisturbed soil always had the greater strength (penetration resistance), and root growth was always greater
in the repacked soil with no macrostructure than it was in the soil with macrostructure intact. At equal high strength (low
water potentials) it appeared that root growth was better when soils were structured. When strength was low (high water potentials),
root growth was better in the unstructured soil.
Soils were then compared during drying cycles over 21 days. The average rate at which roots grew to a depth of 60 mm, and
also the final percentage of plants with a root reaching 60 mm depth, was greatest in repacked soils without macrostructure.
The species of vegetation growing in the soil before the experiment affected root growth in undisturbed soil; growth was slower
where annual grasses and white clover had grown compared with soil which had supported a perennial grass.
It appears that relatively few roots locate and grow in the macrostructure. Other roots grow in the matrix, if it is soft
enough to be deformed by roots. Roots in the matrix of a structured soil grow more slowly than roots in structureless soil
of equal bulk density and water potential. The development of macrostructure in an otherwise structureless soil, of the type
studied, is of no advantage to most roots. However, once a macrostructure has developed, the few roots locating suitable macropores
are able to grow at low water potential when soil strength is high. The importance of macrostructure to establishing seedlings
in the field lies in rapid penetration of at least a few roots to a depth that escapes surface drying during seasonal drought.
ei]{gnB E}{fnClothier} 相似文献