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961.
Ma Rosario de la Torre Angela Casado Ma Encarnación López-Fernández Diana Carrascosa Ma Concepción Casado Domenico Venarucci Vincenzo Venarucci 《Neurochemical research》1996,21(8):885-888
In order to investigate the role of two free radical detoxificant enzymes in patients with aging brain disorders, superoxide
dismutase (SOD) and catalase (CAT) activities have been measured in blood from male and female human patients of different
ages with several types of aging brain disorders. When compared with activities in the normal population, we have detected:
1) SOD and CAT activities are decreased in patients with Parkinson disease. 2) SOD activity seems to be normal and CAT activity
is decreased in patients with dementia. 3) In the patients with stroke, SOD activity is normal, while CAT activity is decreased.
SOD activity was measured in red blood cells using the Minami and Yoshikawa method. CAT activity was measured in hemolysates
by the method of Aebi. We can conclude that SOD and CAT activities in patients with Parkinson disease are decreased. 相似文献
962.
J. F. Romero Collazos M. D. Marrodán E. Gutierrez Redomero 《International Journal of Anthropology》1996,11(1):11-19
Anthropometric characteristics of proportionality, body composition and somatotype have been determined in a group of 72 Spanish
judoists. The sample includes the junior male and female National Team, and seniors competitors in the last Olimpic Games
held in 1992, and participants in the National Championship of 1993. The methodology has been used according to Weiner and
Lourie(1981)and MOGAP procedures described by Borms et al. (1979). The obtained results show a similar proportionality profile
and mesoendomorphic mean somatotype in both male and female series. However, were found significant differences between sexes
as well as depending of weight categories. 相似文献
963.
Mikael Hedrén 《Plant Systematics and Evolution》1996,201(1-4):31-55
Taxa endemic to North-western Europe are rare, but the orchid genusDactylorhiza contains several species restricted to this area. Evidence from morphological and cytological studies have indicated that some species may have arisen recently and may be of hybrid origin. In the present report, I use allozymes to characterize the genomes in various species ofDactylorhiza and evaluate the possibilities for rapid evolutionary change in the genus. Allotetraploid species have evolved repeatedly from two principal diploid ancestral lineages. These lineages include extant diploid and autotetraploid species, from which allotetraploid derivatives may still arise. It is suggested that allotetraploidization dominates over introgression as speciation mechanism in the genus. The more common and widespread allotetraploid species could be characterized by their allozyme characters over considerable distances, indicating that each of them may have a unique origin and that they have spread from their ancestral populations to the present distribution areas. However, it is also possible that some allotetraploid species contain local populations that have been independently derived from the ancestral lineages. 相似文献
964.
Abstract The global regulators agr and sar control expression of cell wall and extracellular proteins. Inactivation of either sar and/or agr in a typical heterogeneously methicillin-resistant Staphylococcus aureus resulted in a small but reproducible decrease in the number of cells in the subpopulation expressing high methicillin resistance. The amount of low affinity penicillin-binding protein PBP2', the prerequisite for methicillin resistance, was apparently not affected, however, a reduction in PBP1 and PBP3 production was observed, suggesting that these resident PBPs of the cells might be involved somehow together with PBP2' in high level methicillin resistance. 相似文献
965.
The dynamics of individual endogenous cytokinins within the growth cycle (subculture interval) of an auxin-dependent and cytokinin-independent cell suspension culture ofNicotiana tabacum L. (strain VBI-0) were determined using high performance liquid chromatography and radioimmunoassay. In cells grown at an optimum auxin concentration the transient maxima of N6-(2-isopentenyl)adenine and N6-(2-isopentenyl)-adenosine correlated with the onset of cell division. Cultivation of the cells in a partially auxin-deprived medium resulted in ca. tenfold increase of all endogenous cytokinins. A very distinct maximum of N6-(2-sopentenyl) adenine appeared at the beginning of subculture. This indicates that a lack of auxin induced an accumulation of cytokinins predominantly in the form of the free bases, which are physiologically more active than the corresponding ribosides.Abbreviations iP
N6-(2-isopentenyl)adenine
- [9R]iP
N6-(2-isopentenyl)adenosine
-
t-Z
trans-zeatin
-
t-[9R]Z
trans-zeatin riboside
- IAA
indole-3-acetic acid
- NAA
1-naphthaleneacetic acid
- 2,4-D
2,4-dichlorophenoxyacetic acid
- f.w.
fresh weight
- SBI
subculture interval
- C
complete medium
- PAD
partially auxin-deprived medium
- RP-HPLC
reverse phase high performance liquid chromatography
- RIA
radioimmunoassay
- PAL
L-phenylalanine ammonia lyase 相似文献
966.
“Bacillus thermoantarcticus” sp. nov., from Mount Melbourne,Antarctica: a novel thermophilic species
B. Nicolaus Licia Lama Enrico Esposito Maria Cristina Manca Guido di Prisco Agata Gambacorta 《Polar Biology》1996,16(2):101-104
A novel thermophilic Gram-positive bacillus, “Bacillus thermoantarcticus”, isolated from geothermal soil near the crater of Mount Melbourne, is described. The organism grows at an optimal temperature
of 63°C at pH 6.0, is oxidase-positive, catalase-negative and produces an exopolysaccharide, an exocellular xylanase, an intracellular
alcohol dehydrogenase and exo- and endocellular α-glucosidase(s). The sequence of 16S rDNA is very similar to that of “Bacillus thermoglucosidasius”; however, the guanine-plus-cytosine (G+C) content is 8 mol% higher. The type strain is “Bacillus thermoantarcticus” (DSM 9572).
Received : 3 February 1995/Accepted : 12 May 1995 相似文献
967.
J. Miranda J. Membrillo-Hernández M. L. Tabche M. Soberón 《Applied microbiology and biotechnology》1996,45(1-2):182-188
A method to isolate mutants with derepressed expression of cytochrome oxidases and better symbiotic performance is presented.
A mutant of Rhizobium etli, CFN030, isolated by its azide-resistant phenotype, was obtained by transposon Tn5-mob mutagenesis. This mutant has a derepressed expression of cytochrome aa3, higher respiratory activities when cultured microaerobically and an improved symbiotic nitrogen fixation capacity. This
phenotype was similar to the previously described mutant CFN037, which was isolated by its increased capacity to oxidize N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPD) [Soberón M et al. (1990) J Bacteriol 172:1676–1680]. We show here that although both mutants have
a similar symbiotic phenotype, they are affected in different genes. Strain CFN030 has the Tn5 inserted in the chromosome while in strain CFN037 the transposon was located in plasmid b. Cytochrome spectral analysis of
both mutant strains in the post-exponential phase of growth, showed the expression of an additional terminal oxidase (cbb3) that is not expressed in the wild-type strain.
Received: 10 April 1995/Received revision: 21 August 1995/Accepted: 7 September1995 相似文献
968.
M. T. Fernández-Espinar S. Vallés F. Piñaga J. A. Pérez-González D. Ramón 《Applied microbiology and biotechnology》1996,45(3):338-341
Using recombinant DNA techniques, an Aspergillus nidulans multicopy transformant for the gene xlnB coding for the minor X24 xylanase has been constructed. When grown on glucose as sole carbon source this transformant secretes 114 U of xylanase (mg
protein)-1. In this culture condition, X24 is the only xylanase secreted and the predominant protein in the culture filtrate. This strategy has been used to purify
the X24 enzyme to homogeneity. The purified xylanase showed a single band on sodium dodecyl sulphate/ polyacrylamide gel electrophoresis
with a molecular mass of 24 kDa and had an isoelectric point of approximately 3.5. The enzyme was a non-debranching endo-1,4-β-xylan
xylanohydrolase highly specific for xylans and showed optimal activity at pH 5.5 and 52°C. The X24 xylanase had a Michaelis constant, K
m, of 12.43 mg oat spelt xylan ml-1 and a V
max of 1639 μmol min-1 (mg protein)-1.
Received: 17 May 1995/Received last revision: 25 September 1995/Accepted: 29 September 1995 相似文献
969.
M. J. Taherzadeh G. Lidén L. Gustafsson C. Niklasson 《Applied microbiology and biotechnology》1996,46(2):176-182
Physiological effects of deficiency of pantothenate, a necessary precursor in the synthesis of coenzyme A, were studied using
the yeast strain Saccharomyces cerevisiae CBS 8066. Cells were grown on defined media in anaerobic batch cultures with glucose (50 g/l) as the carbon and energy source.
Batch cultures containing more than 60 μg/l pantothenate showed no significant differences with respect to growth rates and
product yields. However, with an initial pantothenate concentration of 30 μg/l, the average glucose consumption rate was 50%
lower than in rich medium and, at even lower concentrations of pantothenate, the culture did not consume all the glucose in
the medium. Furthermore, pantothenate deficiency caused the acetate and pyruvate yields to increase and the biomass yield
to decrease, compared to the yields in pantothenate-rich medium. The increased acetate formation could be counteracted by
initial addition of acetate to the medium, and thereby the glycerol yield could be decreased. An initial addition of acetate
of 1.6 g/l to pantothenate-deficient medium (30 μg/l) caused a 35% decrease in glycerol yield and a 6% increase in ethanol
yield. Furthermore, the time required for complete conversion of the glucose decreased by 40%. Acetate addition affected the
acetate and glycerol yields in a similar way in pantothenate-rich medium (1000 μg/l) also.
Received: 27 December 1995/Received revision: 3 May 1996/Accepted: 9 May 1996 相似文献
970.
F. Fierro E. Montenegro S. Gutiérrez J. F. Martín 《Applied microbiology and biotechnology》1996,44(5):597-604
The organization of the genes of the penicillin cluster has been studied in three different mutants of P. chrysogenum impaired in penicillin biosynthesis. The three blocked mutants (derived from the parental strain P. chrysogenum Bb-1) lacked the genes pcbAB, pcbC and penDE of the penicillin biosynthetic pathway and were unable to form isopenicillin N synthase and isopenicillin N acyltransferase. All strains were identified as P. chrysogenum derivatives by fingerprinting analysis with (GTG)n as a probe. The borders of the deleted region were cloned and sequenced, showing the same junction point in the three mutants. The deleted DNA region was found to be identical to that described in P. chrysogenum npe10. The frequent deletion of the pen gene cluster at this point may indicate that this cluster is located in an unstable genetic region, flanked by hot spots of recombination, that is easily lost by mutagen-induced recombination. 相似文献