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2.
Four new species ofCayaponia are described and illustrated: three from Brazil (C. cogniauxiana, C. nitida andC. rugosa) and one from Brazil and Bolivia (C. ferruginea). 相似文献
3.
Solange Faria Lua Figueiredo Norma Albarello Vera Regina Campos Viana 《In vitro cellular & developmental biology. Plant》2001,37(4):471-475
Summary A protocol for in vitro propagation of Rollinia mucosa, an important medicinal plant, was developed. The presence of 500 mg l−1 polyvinylpyrrolidone (PVP) during explant excision was important to avoid browning. Axillary buds, adventitious buds, and
shoot cluster proliferation were achieved from epicotyl and hypocotyl explants from nursery-grown seedlings. The highest direct
organogenesis percentage from hypocotyl explants was obtained upon culture of explants on Murashige and Skoog medium supplemented
with 2.2 μM benzyladenine (BA) plus 2.32 μM kinetin. Epicotyl explants display highest regeneration frequency on a medium containing 8.8 μM BA and 0.54 μM naphthaleneacetic acid. Gibberellic acid was necessary for shoot elongation. Root induction was observed when shoots were
pretreated with activated charcoal for 7 d in the dark before culture on Woody Plant Medium supplemented with 49.21 μM indolebutyric acid for 10 d. Root development was observed when 20 g l−1 sucrose was used. Rooted plantlets were acclimatized and grown in the greenhouse. 相似文献
4.
Evandro M. Moraes Karla S. C. Yotoko Maura H. Manfrin Vera N. Solferini Fábio M. Sene 《Journal of Biogeography》2009,36(11):2136-2147
Aim The aim of this study was to assess the causal mechanisms underlying populational subdivision in Drosophila gouveai , a cactophilic species associated with xeric vegetation enclaves in eastern Brazil. A secondary aim was to investigate the genetic effects of Pleistocene climatic fluctuations on these environments.
Location Dry vegetation enclaves within the limits of the Cerrado domain in eastern Brazil.
Methods We determined the mitochondrial DNA haplotypes of 55 individuals (representing 12 populations) based on sequence data of a 483-bp fragment from the cytochrome c oxidase subunit II (COII) gene. Phylogenetic and coalescent analyses were used to test for the occurrence of demographic events and to infer the time of divergence amongst genetically independent groups.
Results Our analyses revealed the existence of two divergent subclades (G1 and G2) plus an introgressed clade restricted to the southernmost range of D. gouveai . Subclades G1 and G2 displayed genetic footprints of range expansion and segregated geographical distributions in south-eastern and some central highland regions, east and west of the Paraná River valley. Molecular dating indicated that the main demographic and diversification events occurred in the late to middle Pleistocene.
Main conclusions The phylogeographical and genetic patterns observed for D. gouveai in this study are consistent with changes in the distribution of dry vegetation in eastern Brazil. All of the estimates obtained by molecular dating indicate that range expansion and isolation pre-dated the Last Glacial Maximum, occurring during the late to middle Pleistocene, and were probably triggered by climatic changes during the Pleistocene. The current patchy geographical distribution and population subdivision in D. gouveai is apparently closely linked to these past events. 相似文献
Location Dry vegetation enclaves within the limits of the Cerrado domain in eastern Brazil.
Methods We determined the mitochondrial DNA haplotypes of 55 individuals (representing 12 populations) based on sequence data of a 483-bp fragment from the cytochrome c oxidase subunit II (COII) gene. Phylogenetic and coalescent analyses were used to test for the occurrence of demographic events and to infer the time of divergence amongst genetically independent groups.
Results Our analyses revealed the existence of two divergent subclades (G1 and G2) plus an introgressed clade restricted to the southernmost range of D. gouveai . Subclades G1 and G2 displayed genetic footprints of range expansion and segregated geographical distributions in south-eastern and some central highland regions, east and west of the Paraná River valley. Molecular dating indicated that the main demographic and diversification events occurred in the late to middle Pleistocene.
Main conclusions The phylogeographical and genetic patterns observed for D. gouveai in this study are consistent with changes in the distribution of dry vegetation in eastern Brazil. All of the estimates obtained by molecular dating indicate that range expansion and isolation pre-dated the Last Glacial Maximum, occurring during the late to middle Pleistocene, and were probably triggered by climatic changes during the Pleistocene. The current patchy geographical distribution and population subdivision in D. gouveai is apparently closely linked to these past events. 相似文献
5.
The binding of norepinephrine (NE) to plasma proteins of fresh human blood obtained from healthy volunteers was studied by ultrafiltration at different NE concentrations and incubation times at 37 degrees C. At 1.7 nM L-[3H]-NE binding was approximately 25%. The binding was rapid and was not influenced by the incubation time. [3H]-NE could be dissociated from its binding sites by acid precipitation and, after HPLC, showed to be unchanged NE. No difference in NE binding was found between plasma collected in EGTA-GSH or heparin solution. There was no degradation of NE when incubated in plasma at 37 degrees C for 10 h, even without the addition of antioxidants. Therefore, in the present study, binding represented interaction of unchanged NE with plasma proteins. The whole plasma binding was saturable over the range of 0.66 nM to 0.59 mM of NE. Scatchard plot of specific binding revealed high-affinity sites with a Kd of 5.4 nM and a Bmax of 3.9 fmoles.mg-1 protein, and low-affinity sites with a Kd of 2.7 microM and a Bmax of 3.3 pmoles.mg-1 protein. Electrophoretic characterization of NE-binding proteins showed that about 60% of bound NE was associated to albumin, and 20% to prealbumin. NE binding to pure human plasma proteins was also studied using ultrafiltration. Scatchard analyses revealed a single class of very high-affinity binding sites for prealbumin (Kd 4.9 nM), a single class of binding sites for alpha 1-acid glycoprotein (Kd 54 microM) and two classes of binding sites for albumin with high (Kd 1.7 microM) and low (Kd 0.8 mM) affinities respectively. The main results obtained in this study - a) reversibility of NE binding, b) stability of free and bound NE in plasma, c) involvement of the prealbumin as a specific binding protein - point out to a specific transport for NE in human blood plasma. 相似文献
6.
7.
Biochemical dissection of the role of the one-kilodalton carboxyl-terminal moiety of tubulin in its assembly into microtubules 总被引:2,自引:0,他引:2
The 4-kDa C-terminal domain of both tubulin subunits plays a major role in the regulation of microtubule assembly [Serrano et al. (1984) Biochemistry 23, 4675]. Controlled proteolysis of tubulin with subtilisin produces the selective cleavage of this 4-kDa moiety from alpha- and beta-tubulin with a concomitant enhancement of the assembly. Here we show that gradual removal of the last six to eight amino acid residues of the C-terminal region of alpha and beta subunits by an exopeptidase, carboxypeptidase Y, produces a modified protein (C-tubulin) without relieving the modulatory effect of the C-terminal domain and the usual need of MAPs for microtubule assembly. Actually, treatment with this proteolytic enzyme did not change tubulin assembly as promoted by either MAP-2, taxol, MgCl2, dimethyl sulfoxide, or glycerol. The critical concentration for the assembly of C-tubulin remained the same as that for the unmodified tubulin control. Microtubule-associated proteins MAP-2 and tau incorporated into C-tubulin polymers. Clearly, pure C-tubulin did not assemble in the absence of MAPs or without addition of assembly-promoting compounds. However, proteolysis with the exopeptidase induced changes in tubulin conformation as assessed by biophysical methods and double-limited proteolysis. The cleavage with subtilisin after carboxypeptidase digestion did not result in enhancement of the assembly to the levels observed after the treatment of native tubulin with subtilisin. Interestingly, Ca2+ ions affected neither C-tubulin assembly nor depolymerized microtubules assembled from C-tubulin.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
8.
Proteins blotted on nitrocellulose were stained with either 5-dimethylamino-1-naphthalene-sulfonylchloride (dansyl chloride) or fluorescein isothiocyanate. In both cases the staining procedure can be completed in less than 30 min. The sensitivity for detecting fluorescent-labeled proteins on nitrocellulose was 0.5 ng using a dot test. This was accomplished by transparentizing the nitrocellulose with either immersion oil or toluene. Dansylated proteins were successfully utilized for optimizing the electroblotting procedure. In the presence of 0.2% sodium dodecyl sulfate and 20% methanol the distribution of proteins on the nitrocellulose was an exact replica of the protein pattern seen in the polyacrylamide gel. The fluorescent labeling did not affect the antigenic properties of proteins allowing the subsequent probing with antisera. For this procedure, only one set of samples is needed to obtain accurate photographic records of the gel, the nitrocellulose blot, and the probed blot. 相似文献
9.
10.
Polypeptide composition of rat sperm outer dense fibers. A simple procedure to isolate the fibrillar complex 总被引:6,自引:0,他引:6
Treatment of caput or cauda epididymal rat sperm with a low concentration (0.05%) of the cationic detergent cetyltrimethylammonium bromide and 30 mM 2-mercaptoethanol solubilized most of the sperm structures except for the sperm head and the outer dense fiber-connecting piece complex. The latter were purified, and about 10% of these complexes are formed by nine fibers attached to the connecting piece. Of these fibers, two are shorter than the other seven and presumably correspond to fibers 3 and 8 (Fawcett, D.W. (1975) Dev. Biol. 44, 394-436). Electron microscopy confirmed the purity of the isolated outer dense fibers and revealed their characteristic irregular cross-sectional shape. Polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate showed six major polypeptides (Mr = 87,000, 30,400, 26,000, 18,400, 13,000, and 11,500) with a high content of serine, aspartic and glutamic acids, proline, cysteine, leucine, and tyrosine. Furthermore, several lines of evidence indicate a close structural relationship between the components of 30,400 and 26,000 Da. The six major components of the fibers are phosphorylated at serine residues. These results indicate that the major components of rat sperm outer dense fibers are a unique family of phosphoproteins. 相似文献