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1.
Helena Ceretti Diana Vullo Anita Zalts Silvana Ramírez 《World journal of microbiology & biotechnology》2010,26(5):847-853
The aim of this study was to evaluate complexing capacity (CC) accompanying microbial growth in a metal supplemented culture medium. A combined strategy of square wave anodic stripping voltammetry (SWASV) monitored titration and ion-exchange resins treatment (Chelex 100) has been applied. Culture medium, supplemented with Cd(II) in excess to ligands, was inoculated with an indigenous bacterial culture; total ligand concentration and stability constants were determined at different bacterial growth stages. As far as known, determination of CC in such conditions has not been reported (usually ligands in natural or wastewaters exceed metal concentration). HIDA, (N-(2-hydroxyethyl)iminodiacetic acid), was used as a model ligand to mimic soluble products derived from the resin treatment and bacterial metabolism. Ligand concentration, Lt (1.3 ± 0.1 μM), and the conditional stability constant, K′, (log K′ = 5.7 ± 0.2) were in good agreement with expected values (1.0 ± 0.1 μM and log K′ = 6.1). In the supplemented culture medium, total ligand concentration in the micromolar range (60–80 μM) and conditional stability constants (5.5 < log K′ < 6.5) were determined. Cd(II) complexes detected in the different stages of microbial growth are labile from an electrochemical point of view. Results were compared to the case of Cd(II) non-supplemented broth. 相似文献
2.
RPNI, a combination of three commercially available growth media (RPMI-1640, NCTC-135 and IMDM) has been found to support long term continuous cultivation of 3D7 strain of Plasmodium falciparum in the presence of 10% bovine calf serum. During the present study, the suitability of this medium was evaluated for the development of P. falciparum in the presence of horse, goat and rabbit sera as well as various concentrations of ALBUMAX II. RPNI medium supplemented with 10% bovine calf serum (RPNI-BCS) was used as control. The cultures were maintained in candle jars protocol and parasitaemia was monitored daily up to day 7. Horse, goat and rabbit sera all supported the development of P. falciparum. Horse serum gave best results in RPNI medium and supported continuous culture up to day 100. The parasitaemia in the presence of ALBUMAX was significantly higher in RPNI than in RPMI-1640. Addition of hypoxanthine in RPMI-1640 caused an increase in parasitaemia whereas no obvious advantage could be observed in RPNI. The findings exhibited that medium RPNI has an edge over conventional RPMI-1640 medium for in vitro cultivation of P. falciparum. 相似文献
3.
Ana Claudia Ferreira da Cruz Diego Ismael Rocha Lourdes Iarema Marília Contim Ventrella Marcio Gilberto Cardoso Costa Vespasiano Borges Paiva Neto Wagner Campos Otoni 《In vitro cellular & developmental biology. Plant》2014,50(1):76-83
The organogenic potential of root explants derived from cultured seedlings of Bixa orellana L. (annatto) was investigated in response to different incubation conditions and either 4.44 μM 6-benzyladenine, 4.54 μM Thidiazuron, or 4.56 μM Zeatin. Explants cultured in liquid media with agitation generally showed better development of adventitious buds versus explants cultured on semi-solid media. The most adventitious buds developed from explants cultured in liquid media under a 16-h photoperiod. Use of Zeatin and Thidiazuron promoted the development of more adventitious buds than 6-benzyladenine but morphological abnormalities among regenerating shoots and plants were observed. Fewer adventitious buds developed from explants cultured in liquid media supplemented with 6-benzyladenine, but the buds gave rise to the highest percentage of morphologically normal regenerated plants. Histological analyses showed that adventitious buds originated from cell proliferation within the pericycle, opposite the protoxylem poles of the explant. Seedling root tissue is useful for in vitro propagation of B. orellana. 相似文献
4.
Transport of H+, K+, Na+ and Ca++ in Streptococcus 总被引:6,自引:0,他引:6
D. L. Heefner 《Molecular and cellular biochemistry》1982,44(2):81-106
Summary The streptococci differ from other bacteria in that cation translocations (with the possible exception of one of the K+ uptake systems) occur by primary transport systems, i.e., by cation pumps which use directly the free energy released during hydrolysis of chemical bonds to power transport. Transport systems in other bacteria, especially for Na+ and Ca++, are often secondary, using the free energy of another ion gradient to drive cation transport. In streptococci H+ efflux occurs via the F1F0-ATPase. This enzyme is composed of eight distinct subunits. Three of the subunits are embedded in the membrane and form a H+ channel; this is called the F0 portion of the enzyme. The other five subunits form the catalytic part of the enzyme, called F1, which faces the cytoplasm and can easily be stripped from the membrane. Physiologically, this enzyme functions as a H+-ATPase, pumping protons out of the cell to form an electrochemical proton gradient,
. The F1F0-ATPase, however, is fully reversible and if supplied with Pi, ADP and a
+ of sufficient magnitude (ca –200 mv) catalyzes the synthesis of ATP.
Streptococcus faecalis can accumulate K+ and establish a gradient of 50 000:1 (in>out) under some conditions. Uptake occurs by two transport systems. The dominant, constitutive system requires both an electrochemical proton gradient and ATP to operate. The minor, inducible K+ transport system, which has many similarities to the K+-ATPase of the Kdp transport system found in Escherichia coli, requires only ATP to power K+ uptake.Sodium extrusion occurs by a Na+/H+-ATPase. Exchange is electroneutral and there is no requirement for a
. The possibility that the Na+/H+-ATPase may consist of two parts, a catalytic subunit and a Na+/H+ antiport subunit, is suggested by the finding that damage to the Na+ transport system either through mutation or protease action leads to the appearance of
-requiring Na+/H+ antiporter activity.Ca++ like Na+ is extruded from metabolizing, intact cells. Transport requires no
but does require ATP. Reconstitution of Ca++ transport activity with accompanying Ca++-stimulated ATPase activity into proteoliposomes suggests that Ca++ is transported by a Ca++-translocating ATPase.Where respiring organelles and bacteria use secondary
transport systems the streptococci have developed cation pumps. The streptococci, which are predominantly glycolyzing bacteria, generate a
much inferior to that of respiring organisms and organelles. The cation pumps may have developed simply in response to an inadequate
.Abbreviations
electrochemical potential of protons
-
membrane potential
- pH
pH gradient
- p
proton-motive force
- DCCD
N,Na1-dicyclohexlcarbodiimide
- TCS
tetrachlorosalicylanilide
- FCCP
carbonylcyanide-p-trifluoromethylphenylhydrazone
- CCCP
carbonylcyanie-m-chlorophenylhydrazone
- TPMP+
triphenylmethyl phosphonium ion
- DDA+
dibenzyldimethylammonium ion
- Hepes
4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid
- EGTA
ethyleneglycol-bis (amino-ethyl-ether)-N,N-tetraacetic acid 相似文献
5.
Reynoso-Cuevas L Gallegos-Martínez ME Cruz-Sosa F Gutiérrez-Rojas M 《Bioresource technology》2008,99(14):6379-6385
The effect of a hydrocarbon mixture (HCM) of three polycyclic aromatic hydrocarbons (PAH) and Maya crude oil on germination, growth and survival of four grasses (Bouteloua curtipendula, Cenchrus ciliaris, Echinochloa crusgalli and Rhynchelytrum repens) was studied and compared to a control (Festuca arundinacea) under in vitro conditions. The species were cultured on MS medium with different HCM initial concentrations. Germination was not affected for any assayed concentration; however, the length of the stems and roots decreased when HCM increased and the survival of the four species also diminished. Except for F. arundinacea, a direct link between hydrocarbon concentration and plant survival was observed. In vitro studies are clean and easy to handle techniques allowing isolation of the plant activity from that derived from associations with microorganisms in non-sterile cultures. To our knowledge, this is the first work towards phytoremediation assisted by in vitro plant cultivation. 相似文献
6.
Matías Morales Arturo F. Wulff Renée H. Fortunato Lidia Poggio 《Plant Systematics and Evolution》2014,300(5):803-817
In this work, chromosome numbers and karyotype parameters of 36 taxa of the genus Mimosa were studied, especially from the southern South America center of diversification. Results support that x = 13 is the basic chromosome number in the genus. Polyploidy is very frequent, ca. 56 % of the total of the studied species here are polyploid, confirming that polyploids are more frequent at higher latitudes. The most common ploidy levels found are 2x and 4x, but some species studied exhibit 6x and 8x. In different groups, several ploidy levels were found. Parameters of chromosome size show statistically significant differences between close species, and asymmetry index A 2 exhibited low variation between them. It is possible to infer variations of chromosome size between diploids and tetraploids and between basal and derived taxa. The present studies confirm or reveal polyploidy in several groups of South America which are highly diversified in the southernmost area of distribution of the genus, such as sect. Batocaulon ser. Stipellares and sect. Calothamnos. Our data are discussed in a taxonomic context, making inferences about the origin of some polyploid taxa. Polyploidy could be an important phenomenon that increases the morphologic diversity and specific richness in southern South America. On basis of our data, it is possible to hypothesize hybridization between same-ploidy level or different ploidy level taxa. As already shown in the literature, our results confirm the importance of the polyploidy in the speciation of the genus. 相似文献
7.
8.
Bovine follicular oocytes were matured in TCM 199 supplemented with: (1) fetal calf serum (FCS, 20% v/v), Luteinizing Hormone (LH, 10 ug/ml), and Estradiol-17-beta (E(2), 1 ug/ml) in Experiment 1; (2) 20% cow serum recovered at standing estrus (Experiment 2); or (3) 20% FCS (Experiment 3). Maturation, fertilization, and initial cleavage development were evaluated at 16 and 48 h after in vitro insemination. The proportions of oocytes fertilized after maturation in the presence of added hormones (78.5%, Experiment 1) or estrous serum (71.3%, Experiment 2) were significantly higher (p < 0.01) than after use of FCS alone (39.3%, Experiment 3). Cleavage of zygotes within 48 h post-insemination differed significantly (p < 0.01) between maturation treatments, 27.3%, 75.5% and 6.6% for Experiments 1, 2, and 3, respectively. Results demonstrate a beneficial influence of estrous cow serum, characterized by an elevated concentration of LH, on bovine oocyte maturation in vitro. 相似文献
9.
The in vitro rooting of myrtle (Myrtus communis L.) plantlets was performed in containers with gas permeable (V) and non-permeable (C) closures characterized by a different number of gas exchanges (1.4 and 0.3 h− 1, respectively). The rooting was induced on Perlite, soaked with half strength Murashige and Skoog (MS) medium with 0.5 mg dm−3 IBA, either with and without 15 g dm−3 of sucrose. During the rooting phase, it was demonstrated that C cultures without sucrose (C−) negatively affect the growth of myrtle plantlets. The net photosynthetic rate and the starch content showed the lowest values in C cultures with and without sucrose (C+ and C−) while chlorophyll a content did not vary among treatments, therefore it could not be considered an indicative parameter to evaluate the autotrophic metabolism in myrtle plantlets. Electron microscopy and image analysis were employed to evaluate the leaf ultrastructure at three sample dates. Plantlet rooted in vented vessels with and without sucrose (V+ and V−) showed chloroplasts with numerous starch inclusions, while several osmiophilic plastoglobules (frequently related with leaf senescence) were found in chloroplast of leaf cells of C− myrtle plantlets. 相似文献
10.
Na+ and K+ binding by glycerinated muscle fibers with reciprocal cation concentrations in the medium
The binding of Na+ and K+ by glycerinated muscle fibres was observed at reserve concentrations of NaCl in the medium. Under external concentrations of Na+ of K+ up to 0.4-0.5 mM, a constant fraction (0.15-0.25 mmoles/kg dry weight of the fibres) bound by glycerinated fibres was revealed. With the increase of NaCl or KCl concentration in the medium up to 10 mM the concentration of bound cations increased too. The parameters of Na+ and K+ sorption by glycerinated models were calculated. The values of Na+ and K+ binding limits were 4.4 and 1.8 mmole/kg dry weight of the fibres and those of affinity, 3.2 and 4.1 kcal/mol, respectively. The binding of one cation took place in conditions when its concentration was 10,000-20,000 fold less than that of the other cation. This points to the fact that Na+ and K+ binding is highly specific and is carried out by different centres. It is suggested that myosin ATPase is a substratum binding Na+ and K+ in glycerinated muscle fibres at reverse ratio concentrations of these cations in the medium. 相似文献
11.
Mechanism and role of Na + -Ca ++ competition in (NaK)-ATPase 总被引:1,自引:0,他引:1
12.
Liu J Tian J Haas M Shapiro JI Askari A Xie Z 《The Journal of biological chemistry》2000,275(36):27838-27844
We have shown previously that partial inhibition of the cardiac myocyte Na(+)/K(+)-ATPase activates signal pathways that regulate myocyte growth and growth-related genes and that increases in intracellular Ca(2+) concentration ([Ca(2+)](i)) and reactive oxygen species (ROS) are two essential second messengers within these pathways. The aim of this work was to explore the relation between [Ca(2+)](i) and ROS. When myocytes were in a Ca(2+)-free medium, ouabain caused no change in [Ca(2+)](i), but it increased ROS as it did when the cells were in a Ca(2+)-containing medium. Ouabain-induced increase in ROS also occurred under conditions where there was little or no change in [Na(+)](i). Exposure of myocytes in Ca(2+)-free medium to monensin did not increase ROS. Increase in protein tyrosine phosphorylation, an early event induced by ouabain, was also independent of changes in [Ca(2+)](i) and [Na(+)](i). Ouabain-induced generation of ROS in myocytes was antagonized by genistein, a dominant negative Ras, and myxothiazol/diphenyleneiodonium, indicating a mitochondrial origin for the Ras-dependent ROS generation. These findings, along with our previous data, indicate that increases in [Ca(2+)](i) and ROS in cardiac myocytes are induced by two parallel pathways initiated at the plasma membrane: One being the ouabain-altered transient interactions of a fraction of the Na(+)/K(+)-ATPase with neighboring proteins (Src, growth factor receptors, adaptor proteins, and Ras) leading to ROS generation, and the other, inhibition of the transport function of another fraction of the Na(+)/K(+)-ATPase leading to rise in [Ca(2+)](i). Evidently, the gene regulatory effects of ouabain in cardiac myocytes require the downstream collaborations of ROS and [Ca(2+)](i). 相似文献
13.
Mao J Wu G Smith MF McCauley TC Cantley TC Prather RS Didion BA Day BN 《Biology of reproduction》2002,67(4):1197-1203
Developing a culture system for preantral follicles has important biotechnological implications due to the potential to produce large number of oocytes for embryo production and transfer. As an initial step toward accomplishing this long-term goal, a study was conducted to determine the effects of culture medium, serum type, and different concentrations of FSH on preantral follicular development in vitro. Specific endpoints included follicular growth rate, antrum formation, recovery rate of cumulus cell-oocyte complexes (COCs) from follicles, and oocyte meiotic competence. Compared with the North Carolina State University medium 23 (NCSU23), preantral follicles cultured in TCM199 medium for 4 days grew faster (P < 0.02). However, more follicles cultured in NCSU23 differentiated to form an antrum than in TCM199 (P < 0.01). For this reason, NCSU23 was chosen to investigate the role of FSH and serum type in regulating preantral follicular growth. Compared with the 0 mIU/ml FSH control, addition of 2 mIU/ml FSH to the medium stimulated follicular growth and antrum formation and suppressed apoptosis of granulosa cells (P < 0.05), supporting the essential role of FSH in preantral follicular growth and development. Another experiment compared fetal calf serum (FCS) with prepubertal gilt serum (PGS) and studied different concentrations of FSH in the culture medium (0.5, 1, and 2 mIU/ml). The best follicular growth rate was obtained with 2 mIU/ml compared with 0.5 or 1 mIU/ml FSH. Compared with PGS, FCS supplementation increased the cumulative percentage of antral follicles and COC recovery rate (P < 0.04). None of the oocytes recovered from any of these experiments reached metaphase II stage after maturation in vitro. In summary, culture medium, serum type, and FSH concentration in the medium interacted to affect follicular growth and antrum formation in vitro. These results suggest that a longer term culture of preantral follicles (>4 days) may be needed to produce oocytes capable of undergoing meiosis in vitro. 相似文献
14.
15.
B. GROSSO M. SAINT-MARTIN J. VASSAL 《Botanical journal of the Linnean Society. Linnean Society of London》1994,116(4):325-341
The stomatal types of 102 species illustrating the different subdivisions of Bentham's classification of the genus Acacia were studied at two or three ontogenetic stages: first pinnate leaf to bipinnate leaves or to phyllode. Six stomatal types are recognized on the basis of Guyot's nomenclature (1966): 1, 2, 3, 4, 4', 6; a new type (3') is described. The specialization of the leaf up to the phyllode stage is followed by a decrease of diversity of the stomatal formula and an increasing frequency of the 'basic core' 3, 3', 4. The distinction between the two Australian groups of bipinnate species (series Pulchellae and Botrycephalae) is confirmed. Possible relationships between the cosmopolitan series Vulgares (the most primitive group) and some Australian taxa as well as between the Pulchellae and some phyllodic species from the Australian series Phyllodineae are commented on. The series Gummiferae looks quite distinct from other groups. 相似文献
16.
Somatocrinin (growth hormone releasing factor) in vitro bioactivity; Ca++ involvement, cAMP mediated action and additivity of effect with PGE2 总被引:4,自引:0,他引:4
Paul Brazeau Nicholas Ling Frederick Esch Peter Böhlen Christiane Mougin Roger Guillemin 《Biochemical and biophysical research communications》1982,109(2):588-594
The release of GH induced by purified hypothalamic GRF or native or synthetic tumor-derived GRF is antagonized by the presence of CoCl2; it is simulated by 8Br .cAMP, IBMX, cholera toxin, forskolin, with identical maximal effects (Emax). Somatocrinin (GRF) stimulates the efflux of cAMP by the pituitary cells in parallel to the release of GH. Addition of either 8Br .cAMP, IBMX, cholera toxin or forskolin to a maximally stimulating dose of GRF does not increase the response which remains GRF-Emax. In contradistinction with these results PGE2 releases GH with a dose-response curve different from that of GRF, and the combination of PGE2 + GRF produces an Emax far greater than that due to either agonist alone; showing a true additivity. The name is proposed to replace the acronym GRF. 相似文献
17.
Jorge M. Canhoto Maria Ludovina S. Guimarães Gil S. Cruz 《Plant Cell, Tissue and Organ Culture》1990,21(2):171-177
Pollen of Iochroma warscewiczii Regel (Solanaceae) produced embryogenic calli or embryos inside anthers cultured on Nitsch & Nitsch medium. Two distinct pathways could be recognized in this process, one involving mainly the vegetative cell, and the second starting with two equal cells in the pollen grains.In all media tested, androgenesis initiation was highest when anthers contained pollen at the first mitosis, or close to it, at inoculation. High sucrose (7%) and calcium (11.3 mM) concentrations were found to be highly desirable for the induction of androgenesis in this species. Addition of benzylaminopurine (0.5 mg l–1) to the culture medium seems to slightly improve callus or embryo production. When all three factors were present at optimal concentrations as much as 13.9% of inoculated anthers were found to be embryogenic.Plantlet development from pollen embryos required lower sucrose (3%) and a combination of 0.1 mg l–1 benzylaminopurine and 0.5 mg l–1 gibberellic acid in the culture medium. Cytological analysis of 55 regenerated plantlets showed that about 49% were haploids, but diploid (ca. 49%) and triploid (ca. 2%) plants were also obtained. 相似文献
18.
Ljiljana Radojević Nevena Djordjević Branka Tucić 《Plant Cell, Tissue and Organ Culture》1989,17(1):21-26
Uninuclear microspores in red horse chestnut anther cultures formed pollen embryos and plantlents in MS agar medium supplemented with varying 2,4-D concentrations (1.0, 1.5 or 2.0 mg l-1) and 1.0 mg l-1 Kin. The highest number of embryogenic anthers (38%) was obtained in MS medium containing 1.0 mg l-1 of each 2,4-D and Kin. The ability of pollen embryos to germinate was closely correlated with normal embryo morphology and was influenced by hormone content in the medium (MS+;1.0 mg l-1 IAA+1.0 mg l-1 GA3+0.1 mg l-1 Kin+400 mg l-1 glutamine). Pollen embryos and plantlets had the haploid chromosome number (x=n=40). Cytological examinations demonstrated pollen dimorphism of this Aesculus species.Abbreviations AC
activated charcoal
- 2,4-D
2,4-dichlorophenoxyacetic acid
- IAA
indole-3-acetic acid
- Kin
6-furfurylaminopurine
- GA3
gibberellic acid
- MS
Murashige and Skoog 相似文献
19.
20.
Ethnobotanical information about uses, management and traditional classification ofLeucaena esculenta by the Mixtec in Guerrero, Mexico, is presented. This plant is mainly used as human food. Buds of leaves and flowers as well as seeds and young pods are the main edible parts. Size, flavor and digestibility of seeds and pods are shown to be important in the Mixtec classification ofLeucaena species and in selection of trees to harvest during gathering. Artificial selection inL. esculenta subsp.esculenta by the Mixtec occurs not only under cultivation, but also in wild populations where people eliminate some individuals while promoting the growth of others with favorable phenotypes. Morphological characters of seeds and pods of individual trees of this subspecies were measured in order to compare phenotypic variation in populations subject to different regimes of management. Samples of trees were analyzed from a) a wild population not affected by intentional disturbances; b) a wild population selectively managed in situ; and c) a sample of cultivated individuals. Ordination methods and analysis of variance were used to examine differences between populations. A marked divergence between the three samples was found, especially between the wild populations managed and unmanaged. The frequency of the phenotypes preferred by people was found to be higher in the wild populationin situ managed. Our study confirms that through in situ forms of management, people are able to modify the phenotypic structure of plant populations. Possible routes of plant domestication within plant populationsin situ are suggested. 相似文献