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101.
Paula Veríssimo Cristina Esteves Carlos Faro Euclides Pires 《Biotechnology letters》1995,17(6):621-626
The flowers of cardoon (genus Cynara) are traditionally used in Portugal for cheese making. In this work the vegetable rennet of the species Cynara cardunculus L. was characterized in terms of enzymic composition and proteolytic specificity of its proteinases (cardosin A and cardosin B). Cardosin A was found to cleave insulin B chain at the bonds Leu15-Tyr16, Leu17-Val18 and Phe25-Tyr26. In addition to the bonds mentioned cardosin B cleaves also Glu13-Ala14, Ala14-Leu15 and Phe24-Phe25 indicating that it has a broader specificity. The kinetic parameters for the hydrolysis of the synthetic peptide Leu-Ser-Phe(NO2)-Nle-Ala-Leu-oMe were also determined and compared to those of chymosin and pepsin. The results obtained indicate that in terms of specificity and kinetic parameters cardosin A is similar to chymosin whereas cardosin B is similar to pepsin. It appears therefore that the enzyme composition of cardoon rennet closely resembles that of calf rennet. 相似文献
102.
We examined the effects of the conversion of tropical forest to pasture on soil organic matter (SOM) origin and quality along
a chronosequence of sites, including a primary forest and six pastures. Bulk soil samples received a physical size-fractionation
treatment to assess the contribution of each compartment to total SOM pool. Besides a general increase in total C and N stocks
along the chronosequence, we observed a reduction of the relative contribution of the coarser fractions to total soil C content,
and an increased concentration in the finer fractions. The origin of the C in each size fraction was established from measurements
of13C abundance. After 80 years about 93% of the C in the least humified fraction of the top 10 cm of soil was of pasture origin,
while in the most humified it was 82%. Chemical analyses indicated that the fine silt and coarse clay fractions contained
the most refractory carbon. 相似文献
103.
Roberto Gomes daSilva Fernando Ryuiti Minomo 《International journal of biometeorology》1995,39(2):69-73
Nychthemeral and annual rhythms of the rectal temperature were determined for Corriedale sheep in a tropical climate. The minimum rectal temperature averaged 39.55° C at 0500 hours in summer, and 38.87° C at 0600 hours in winter. The maximum was 40.03° C in summer (1700 hours) and 39.33° C in winter (1830 hours). Annual cycle of the rectal temperature showed a minimum in July and maximum in December. 相似文献
104.
The age, growth and reproduction ofRutilus lemmingii (Steindachner, 1866), an endemic cyprinid from the Iberian Peninsula, was studied for over a period of two years in a small seasonal tributary of the Guadalquivir river basin. Approximately 65 % of the total growth in length occured in the first year of life. Males reached a maximum age of 3+ yr (Fork Length, F.L. = 114 mm) and females 4+ yr (F.L. = 144 mm). Both sexes matured during their second year of life (1 +). The overall sex ratio (334 males to 389 females) differed significantly from unity. Somatic condition decreased markedly during the reproductive period of March to May.R. lemmingii is a multiple spawner and releases two batches of eggs per female each year. Mean egg diameter of the first batch was larger than the second one. The regression between fecundity and Fork Length (mm) was: Fec = 0.014 F.L.Z.2.858 Compared with available information, thisR. lemmingii population, located at a lower latitude, is characterized by fast growth, early maturity, high level of reproductive effort, and a short life-span. These life-history characteristices are typical of species in unstable environments, where adult mortality is high, variable or unpredictable. 相似文献
105.
Angela S. Barbosa Thaís E. Ferraz-Costa Mauro Semer Bernardo Liberman Carlos A. Moreira-Filho 《Human genetics》1995,95(1):63-66
This paper reports a case of XY gonadal dysgenesis in two sisters. Both patients presented an eunochoid female phenotype with normal external genitalia. At laparotomy, the elder sister was found to have bilateral gonadoblastoma. Cytogenetic studies, which included G and C banding and in situ hybridization, showed that the patients had an apparently normal 46, XY karyotype. PCR analyses revealed absence of the conserved portion (HMG box) of the SRY gene and of the Y chromosome pseudoautosomal boundary region sequence in both patients. The presence of the ZFY sequence was detected by Southern hybridization in the two affected sisters. The patients' father (46, XY, no mosaicism detected in peripheral blood lymphocytes) was positive for SRY and ZFY sequences. The occurrence of gonadoblastoma is discussed in terms of the genetic factors that may lead to tumor development. 相似文献
106.
Bernardo Celda Clelia Biamonti Maria Jose Arnau Roberto Tejero Gaetano T. Montelione 《Journal of biomolecular NMR》1995,5(2):161-172
Summary A large portion of the 13C resonance assignments for murine epidermal growth factor (mEGF) at pH 3.1 and 28°C has been determined at natural isotope abundance. Sequence-specific 13C assignments are reported for 100% of the assignable C, 96% of the C, 86% of the aromatic and 70% of the remaining peripheral aliphatic resonances of mEGF. A good correlation was observed between experimental and back-calculated C chemical shifts for regions of regular -sheet structure. These assignments also provide the basis for interpreting 1H–13C heteronuclear NOE (HNOE) values in mEGF at natural isotope abundance. Some of the backbone polypeptide segments with high internal mobility, indicated by these 1H–13C HNOE measurements, correlate with locations of residues involved in the putative mEGF-receptor binding site. Using four families of mEGF structures obtained over the last few years, we demonstrate that standard deviations between experimental and back-calculated C values can be used to monitor the refinement of this protein's structure, particularly for -sheet regions. Improved agreement between calculated and observed values of C is correlated with other measures of structure quality, including lowered values of residual constraint violations and more negative values of conformational energy. These results support the view that experimental conformation-dependent chemical shifts, C, can provide a reliable source of information for monitoring the process of protein structure refinement and are potentially useful restraints for driving the refinement.Abbreviations HSQC
heteronuclear single-quantum coherence spectroscopy
- PFG
pulsed-field gradient
- TOCSY
1H-1H total correlation spectroscopy
- EGF
epidermal growth factor
- mEGF
murine EGF
- hEGF
human EGF
- hTGF
human type- transforming growth factor
- DIPSI
spm-locking pulse sequence
- NOE
nuclear Overhauser effect
- HNOE
heteronuclear Overhauser effect 相似文献
107.
Danley A. S. Callieri Carlos G. Núñez Juan C. Díaz Ricci Luis Scidá 《Applied microbiology and biotechnology》1984,19(4):267-271
Summary
Candida utilis var. major NRRL-Y-1084 was grown in a defined medium without a phosphorous (P) source. During the exponential phase, cells divided according to a specific growth rate of 0.32 h-1, which is lower than the usual rate for a balanced medium (0.4–0.6 h-1). The relative P content of the biomass decreased from 2.70% to 0.75% over a period of 6 h, including 2 h of cell division arrest. At the end of this period there was another interruption of cell division. After that, multiplication restarted at a considerably lower rate and it deviated slightly from the exponential pattern. The stationary phase began when biomass P content reached 0.4%–0.5%, slowly decreasing afterwards to 0.25–0.20%. Biomass synthesis was less affected than cell division by the relative decrease of endogenous P, the two processes differing partially in their kinetics. Cell lysis started shortly before the stationary phase and affected about 20% of the population by the end of the assay. RNA and P content of the resulting biomass were 2.4% and 0.25% respecitvely, P being mainly incorporated to RNA.The relationship of biomass production to glucose uptake was very low, probably because the marked P deficiency called for an increase in energy consumption for growth and specially for maintenance. Compared with yeasts grown in a balanced medium, 40% increase in glycogen was observed, whereas no mean changes in the content of cell wall carbohydrates (glucan and mannan) and that of true protein were found.Member of the Scientific Researcher's Career of the Consejo Nacional de Investigaciones Cientificas y Técnicas (CONICET). Agrentina 相似文献
108.
Teresita A. Lisa Mónica N. Garrido Carlos E. Domenech 《Molecular and cellular biochemistry》1984,63(2):113-118
Summary Different compounds derived from choline, and obtained by demethylation or by oxidation of the primary alcohol group with subsequent N-demethylation, were tested as inducer agents of acid phosphatase and cholinesterase in Ps. aeruginosa. It was found that betaine and dimethylglycine were the most effective inducers of both enzyme activities. These metabolites including choline itself, were not inducers of acid phosphatase and cholinesterase in other Gram-negative bacteria such as: Escherichia coli, Salmonella typhimurium, Shigella flexneri, Enterobacter liquefacciens and Proteus mirabilis. The acid phosphatase activities found in these bacteria were not inhibited in vitro by choline, betaine and phosphorylcholine. From these results it may be concluded that the acid phosphatase activity from Ps. aeruginosa is different from the same activity observed in the other bacteria. In addition, it is also shown that Ps. aeruginosa acid phosphatase and cholinesterase were inhibited by a number of compounds containing a positively charged amino group, with methyl or ethyl groups bound to it. These results seem to confirm that Ps. aeruginosa acid phosphatase and cholinesterase may contain a similar anionic site. 相似文献
109.
Parodi Armando J. Blank Edward W. Peterson Jerry Ceriani Roberto 《Molecular and cellular biochemistry》1984,58(1-2):157-163
Summary Membranes isolated from mouse and human milk fat globules were found to contain the enzymes responsible for the synthesis of dolichol monophosphate mannose and dolichol monophosphate glucose as well as those involved in the transference of the glycosyl residues from the two dolichol derivatives to dolichol diphosphate oligosaccharides. The levels of most of the enzymes were comparable to those found in mouse mammary gland microsomes. The presence of enzymes involved in protein glycosylation via dolichol derivatives in the milk fat globule membrane provides evidence in favor of an outward flow of membrane components from the rough endoplasmic reticulum, where these enzymes are active in vivo, towards the cell surface. 相似文献
110.
Cristina Casals Carmen Acebal Jesús Pérez-Gil Roberto Arche 《Molecular and cellular biochemistry》1984,63(1):13-20
Summary Lysolecithin:lysolecithin acyltranferase is an enzyme which in several previous studies has shown a dual behavior catalyzing two types of reaction, transacylation or hydrolysis, with the same substrate. Both activities have shown to be dependent on several environmental conditions and among them, the presence of lipids.The addition of several classes of lipids activated in all the cases the enzyme, decreasing the hydrolysis/transacylation molar ratio. This effect was higher for PC/PE/Chol mixture than for other lipids assayed. Circular dichroism spectra of the enzyme did not show any change with the addition of lipids, concluding that the effect of lipids was not due to any structural change in the protein. The hypothesis has been made of an influence of lipids on the physical state of the substrate as well as, possibly, on the enzyme-substrate interaction.The significance of these effects on the physiological role of lysolecithin:lysolecithin acyltransferase from soluble fraction of rabbit lung is discussed.Abbreviations Chol
cholesterol
- CMC
critical micellar concentration
- DPPC
dipalmitoylphosphatidylcholine
- FA
fatty acid
- H/T
hydrolysis/transacylation molar ratio
- LPC
lysophosphatidylcholine
- PC
phosphatidylcholine
- PE
phosphatidylethanolamine
- TG
triglyceride
- UV
ultraviolet 相似文献