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1.
Francesc Gòdia Carles Casas Bernardo Castellano Carles Solà 《Applied microbiology and biotechnology》1987,26(4):342-346
Summary Data of cell concentration, viability and microscopic observation of cell distribution inside carrageenan immobilized yeast beads are reported. Results were obtained from a continuous packed-bed reactor performing alcoholic fermentation and the main observations made on cell activity are in agreement with the fermentation profiles inside the fermenter. 相似文献
2.
Intracellular microelectrode studies were conducted to investigate the actions of the partial agonist-antagonist nalorphine at an opiate receptor on functional frog skeletal muscle fiber membranes. In high bath concentrations (greater than or equal to 10(-4) M), nalorphine alone produces agonist actions similar to the "full" opiate agonists. These actions were (i) to depress both the sodium and potassium (gNa and gK) conductance increases due to electrical stimulation by a nonspecific local anestheticlike mechanism and (ii) to depress gNa by a specific opiate receptor mediated mechanism. In a much lower bath concentration (1 X 10(-8) M) nalorphine acts to antagonize the specific opiate receptor mediated depression of gNa produced by the "full" agonist meperidine. Thus in this preparation nalorphine, "the partial antagonist," has the same actions as naloxone, which is often considered to be a full antagonist. The quantitative differences observed in the effects of these two opiate antagonists are discussed. 相似文献
3.
4.
A.A. Bernardo F.T. Kear J.A. Stim O.S. Ruiz J.A.L. Arruda 《The Journal of membrane biology》1996,154(2):155-162
We have previously partially purified the basolateral Na+/HCO−
3 cotransporter from rabbit renal cortex and this resulted in a 400-fold purification, and an SDS-PAGE analysis showed an enhancement
of a protein band with a MW of approximately 56 kDa. We developed polyclonal antibodies against the Na+/HCO−
3 cotransporter by immunizing Dutch-belted rabbits with a partially purified protein fraction enriched in cotransporter activity.
Western blot analysis of renal cortical basolateral membranes and of solubilized basolateral membrane proteins showed that
the antibodies recognized a protein with a MW of approximately 56 kDa. The specificity of the purified antibodies against
the Na+/HCO−
3 cotransporter was tested by immunoprecipitation. Solubilized basolateral membrane proteins enriched in Na+/HCO−
3 cotransporter activity were incubated with the purified antibody or with the preimmune IgG and then reconstituted in proteoliposomes.
The purified antibody fraction caused a concentration-dependent inhibition of the Na+/HCO−
3 cotransporter activity, while the preimmune IgG failed to elicit any change. The inhibitory effect of the antibody was of
the same magnitude whether it was added prior to (inside) or after (outside) reconstitution in proteoliposomes. In the presence
of the substrates (NaHCO3 or Na2CO3) for the cotransporter, the inhibitory effect of the antibody on cotransporter activity was significantly blunted as compared
with the inhibition observed in the absence of substrates. Western blot analysis of rabbit kidneys showed that the antibodies
recognized strongly a 56 kDa protein band in microsomes of the inner stripe of outer medulla and inner medulla, but not in
the outer stripe of outer medulla. A 56 kDa protein band was recognized in microsomes of the stomach, liver, esophagus, and
small intestine but was not detected in red blood cell membranes. Localization of the Na+/HCO−
3 cotransporter protein by immunogold technique revealed specific labeling of the cotransporter on the basolateral membranes
of the proximal tubules, but not in the brush border membranes. These results demonstrate that the polyclonal antibodies against
the 56 kDa basolateral protein inhibit the activity of the Na+/HCO−
3 cotransporter suggesting that the 56 kDa protein represents the cotransporter or a component thereof. These antibodies interact
at or near the substrate binding sites. The Na+/HCO cotransporter protein is expressed in different regions of the kidneys and in other tissues.
Received: 27 January 1996/Revised: 23 July 1996 相似文献
5.
The effects of rearing and acclimation on the response of adultDrosophila to temperature were investigated in a gradient.D. melanogaster flies preferred a higher mean temperature and were distributed over a wider range of temperatures thanD. simulans flies. Acclimating adults at different temperatures for a week did not influence the response of either species. Adults reared at 28°C as immatures had a lower mean preference than those reared at cooler temperatures, suggesting that flies compensated for the effects of rearing conditions. Adults from tropical and temperate populations ofD. melanogaster andD. simulans did not differ in the mean temperature they preferred in a gradient, suggesting little genetic divergence for this trait within species. The species differences and environmental responses may be related to changes in optimal physiological conditions for the flies. 相似文献
6.
The effect of adult learning through an oviposition experience, and pre-adult learning through development inside a host was
investigated in two strains of an Australian egg parasitoid,Trichogramma nrivelae (Hymenoptera: Trichogrammatidae). Host response was measured in two types of laboratory preference tests. In single host
tests, females reared on three lepidopteran hosts (Heliothis punctigera (Noctuidae),Papilio aegeus (Papilionidae), andHypolimnas bolina (Nymphalinae)) were presented host eggs individually, and allowed two ovipositions. Pre-adult experience affected host preference
in only one strain, while acceptance of a host was increased in both strains when they had previously oviposited in this host
species. An oviposition experience had a stronger effect on host preference than pre-adult experience. In choice tests, pairwise
combinations of hosts were arranged in an alternating grid. The ratio of host acceptances to host contacts was computed for
the whole test and up to the first oviposition. These indicated that effects of rearing host were weak or absent, but the
host chosen initially had a strong effect on host preference. Relative size of the hosts had a strong effect on choice of
the first host. The implications of learning inTrichogramma are discussed in relation to host preference testing procedures and the selection of candidate strains for mass rearing and
inundative release. 相似文献
7.
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
8.
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
9.
Ectopic ACTH syndrome 总被引:2,自引:0,他引:2
Bernardo L. Wajchenberg Berenice B. Mendon a B. Liberman Maria Adelaide A. Pereira Marvin A. Kirschner 《The Journal of steroid biochemistry and molecular biology》1995,53(1-6):139-151
Ectopic ACTH syndrome represents a cancer-induced amplification of a property [proopiomelanocortin (POMC) peptides production] normally present in the cells from which the cancer originated but with aberrant posttranslational processing of POMC resulting in a greatly elevated secretion of ACTH precursors. The classic ectopic ACTH-producing tumors described in the 1960s were highly malignant but more recently slowly growing tumors such as carcinoids are reported with increasing frequency. Clinical features of patients with ectopic ACTH were analyzed, including biochemical abnormalities, plasma ACTH, cortisol and urinary steroids. Dynamic tests such as high-dose dexamethasone suppression, metyrapone and ovine-CRH (oCRH) stimulation were explored, as well as inferior petrosal sinus ACTH sampling before and after oCRH. Among the tumor markers examined, elevation of ACTH precursors was uniformly present followed by increased output of calcitonin, gut hormones, oncofetal and placental hormones in decreasing order. Since more than 90% of ectopic ACTH tumors are neuroendocrine in nature exhibiting APUD characteristics, their 2 markers, neuron-specific enolase and chromogranins are very useful. The imaging procedures for localization of the tumor ranged from chest X-rays to computed tomography and magnetic resonance of the chest and abdomen. Abdominal ultrasonography was also useful. Finally somatostatin receptor scintigraphy permitted demonstration of unrecognized tumors and/or metastases, even when the tumors were occult. The ACTH content, immunostaining for APUD markers and altered POMC processing were evaluated in ectopic tumors and/or metastases. Occult ectopic ACTH syndrome of more than 4–6 months of symptoms without the emergence of an obvious source was reviewed. Since the tumors are often clinically and biochemically undistinguishable from pituitary-dependent Cushing's disease, inferior petrosal sinus sampling for ACTH after oCRH stimulation established the diagnosis in over 90% of the cases. 60% of the occult tumors were thoracic carcinoids (3/4 bronchial carcinoids), followed by small cell lung cancer and pancreatic neuroendocrine tumors. In 12% the primary etiology was not detected. The rare syndrome of ectopic CRH syndrome (6 published cases) leading to excessive stimulation of the pituitary which became hyperplastic and secreted excessive amounts of ACTH is discussed. Finally, the 12 published cases and 1 unreported patient with ectopic CRH-ACTH tumors were reviewed, the majority being metastatic small cell lung carcinomas, bronchial and thymic carcinoids. 相似文献
10.
The response to a vibration stimulus recorded from the cords of the ventral submuscular plexus of the polyclad flatworm, Notoplana acticola, consists of a burst of action potentials. The response can be abolished by the application of MgCl2 to the sea water bathing the preparation. With repeated application of the stimulus, decreasing numbers of action potentials can be measured. This waning responsiveness can be dishabituated by applying a more intense vibration stimulus or with electrical shocks applied directly to the ventral nerve plexus. With electrical stimuli a number of shocks have to be applied before the response can be dishabituated. Changes in responsiveness can be measured simultaneously in a number of sites in the plexus even after the nerves between recording sites have been severed. With different interstimulus intervals the extent of habituation changes. As interstimulus intervals increase from 1 to 5 sec, there appears to be a decrease in responsiveness which recovers when interstimulus intervals become longer than 5 sec. 相似文献