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1.
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
2.
Shio Jean Lin Christine Figueiredo Leonard J. Sciorra Ming-liang Lee 《Human genetics》1987,76(2):173-175
Summary The induction of fragile sites on human chromosomes has been demonstrated under various conditions that cause thymidylate stress, including exposure to uridine. In this study, we examined common fragile site expression by initially exposing peripheral lymphocytes to uridine, followed by repair of the fragile sites with media containing various concentrations of thymidine. Lymphocytes were cultured in medium 199 with 2 mM uridine. At 0.5, 1, 2, 3, 8, 10, 12, and 18 h before harvest, the uridine medium was removed and replaced by medium containing thymidine at various concentrations. Our results demonstrate that the effect of uridine on chromosome fragility can be reversed by low concentrations of thymidine (2 M up to 200 M) and the rescuing effect of thymidine can be achieved if the cells were treated prior to 2–3 h before harvest. No repair was found if thymidine was added to culture within 2 h prior to harvesting, suggesting that packing of chromosomes is also an important factor in the expression and repair of fragile sites. 相似文献
3.
The alpha-like globin gene cluster in rabbits contains embryonic zeta-
globin genes, an adult alpha-globin gene, and theta-globin genes of
undetermined function. The basic arrangement of genes, deduced from
analysis of cloned DNA fragments, is 5'-zeta 0-zeta 1-alpha 1-theta 1- zeta
2-zeta 3-theta 2-3'. However, the pattern of restriction fragments
containing zeta- and theta-globin genes varies among individual rabbits.
Analysis of BamHI fragments of genomic DNA from 24 New Zealand white
rabbits revealed eight different patterns of fragments containing
zeta-globin genes. The large BamHI fragments containing genes zeta 0 and
zeta 1 are polymorphic in length, whereas a 1.9-kb fragment containing the
zeta 2 gene and the 3.5-kb fragment containing the zeta 3 gene do not vary
in size. In contrast to this constancy in the size of the restriction
fragments, the copy number of the zeta 2 and zeta 3 genes does vary among
different rabbits. No length polymorphism was detected in the BamHI
fragments containing the theta-globin genes, but again the copy number
varies for restriction fragments containing the theta 2 gene. The alpha 1-
and theta 1-globin genes are located in a nonpolymorphic 7.2-kb BamHI
fragment. The combined data from hybridization with both zeta and theta
probes shows that the BamHI cleavage pattern does not vary within the
region 5'-alpha 1-theta 1- zeta 2-zeta 3-theta 2-3', but the pattern
genomic blot-hybridization patterns for the progeny of parental rabbits
with different zeta-globin gene patterns shows that the polymorphic
patterns are inherited in a Mendelian fashion. Two different haplotypes
have been mapped based on the genomic blot-hybridization data. The
variation in the alpha-like globin gene cluster in the rabbit population
results both from differences in the copy number of the duplication block
containing the zeta-zeta-theta gene set and from the presence or absence of
polymorphic BamHI sites.
相似文献
4.
Assignment of orthologous relationships among mammalian alpha-globin genes by examining flanking regions reveals a rapid rate of evolution 总被引:1,自引:0,他引:1
In order to study the relationships among mammalian alpha-globin genes, we
have determined the sequence of the 3' flanking region of the human alpha 1
globin gene and have made pairwise comparisons between sequenced
alpha-globin genes. The flanking regions were examined in detail because
sequence matches in these regions could be interpreted with the least
complication from the gene duplications and conversions that have occurred
frequently in mammalian alpha-like globin gene clusters. We found good
matches between the flanking regions of human alpha 1 and rabbit alpha 1,
human psi alpha 1 and goat I alpha, human alpha 2 and goat II alpha, and
horse alpha 1 and goat II alpha. These matches were used to align the
alpha-globin genes in gene clusters from different mammals. This alignment
shows that genes at equivalent positions in the gene clusters of different
mammals can be functional or nonfunctional, depending on whether they
corrected against a functional alpha-globin gene in recent evolutionary
history. The number of alpha-globin genes (including pseudogenes) appears
to differ among species, although highly divergent pseudogenes may not have
been detected in all species examined. Although matching sequences could be
found in interspecies comparisons of the flanking regions of alpha- globin
genes, these matches are not as extensive as those found in the flanking
regions of mammalian beta-like globin genes. This observation suggests that
the noncoding sequences in the mammalian alpha-globin gene clusters are
evolving at a faster rate than those in the beta-like globin gene clusters.
The proposed faster rate of evolution fits with the poor conservation of
the genetic linkage map around alpha-globin gene clusters when compared to
that of the beta-like globin gene clusters. Analysis of the 3' flanking
regions of alpha-globin genes has revealed a conserved sequence
approximately 100-150 bp 3' to the polyadenylation site; this sequence may
be involved in the expression or regulation of alpha-globin genes.
相似文献
5.
Schistosoma mansoni: defined system for stepwise transformation of cercaria to schistosomule in vitro 总被引:38,自引:0,他引:38
F J Ramalho-Pinto G Gazzinelli R E Howells T A Mota-Santos E A Figueiredo J Pellegrino 《Experimental parasitology》1974,36(3):360-372
Defined conditions are described for the in vitro production of large numbers of tail-free viable schistosomules. These consist of (1) the centrifugation of cold cercarial suspension and the incubation of the packed cercariae in a minimal volume of medium at 30 C for 40 min to effect tail loss and glandular secretion; (2) the isolation of the bodies by resuspension and sedimentation and (3) the induction of surface changes by incubating the bodies in inactivated serum or a defined tissue culture medium for a further 40 min interval at 37 C with mild agitation.The resultant schistosomules are characterized by the depletion of their penetration gland contents, loss of tail, fluoride and water sensitivities, complement insensitivity, negative “Cercarien-hüllen Reaktion,” and loss of the surface coat as demonstrated by periodic acid-Schiff (PAS) staining and electron microscope observations. 相似文献
6.
M C Oliveira I Y Hirata J R Chagas P Boschcov R A Gomes A F Figueiredo L Juliano 《Analytical biochemistry》1992,203(1):39-46
Six intramolecularly quenched fluorogenic peptides related to the sequences Phe8 to His13, His6 to His13, and Tyr4 to His13 of the human angiotensinogen, containing o-aminobenzoyl (Abz) and ethylenediamine dinitrophenyl (EDDnp) groups at amino- and carboxyl-terminal amino acids residues, were synthesized by classical solution methods. The Leu-Val is the only bond of all obtained peptides that was hydrolyzed by human renin with different degrees of purity and was resistant to hydrolysis by pig renin and cathepsin D. The hydrolysis of Abz-His-Pro-Phe-His-Leu-Val-Ile-His-EDDnp by human renin was inhibited by a highly specific transition-state analog of angiotensinogen (IC50 = 7.8 x 10(-9) M), described by K. Iizuka et al. (1990, J. Med. Chem. 33, 2707-2714). Therefore, specific and sensitive substrates for the continuous assay of human renin in which as little as 70 microGU of human renin could be detected by Abz-Phe-His-Leu-Val-Ile-His-EDDnp were described. The optimal pHs of hydrolysis of the substrates were in the range 4 to 6. 相似文献
7.
Separation of abnormal cell wall composition from penicillin resistance through genetic transformation of Streptococcus pneumoniae. 总被引:1,自引:1,他引:0
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Compared with most penicillin-susceptible isolates of Streptococcus pneumoniae, penicillin-resistant clinical isolate Hun 663 contains mosaic penicillin-binding protein (PBP) genes encoding PBPs with reduced penicillin affinities, anomalous molecular sizes, and also cell walls of unusual chemical composition. Chromosomal DNA prepared from Hun 663 was used to transform susceptible recipient cells to donor level penicillin resistance, and a resistant transformant was used next as the source of DNA in the construction of a second round of penicillin-resistant transformants. The greatly reduced penicillin affinity of the high-molecular-weight PBPs was retained in all transformants through both genetic crosses. On the other hand, PBP pattern and abnormal cell wall composition, both of which are stable, clone-specific properties of strain Hun 663, were changed: individual transformants showed a variety of new, abnormal PBP patterns. Furthermore, while the composition of cell walls resembled that of the DNA donor in the first-round transformants, it became virtually identical to that of susceptible pneumococci in the second-round transformants. The findings indicate that genetic elements encoding the low affinity of PBPs and the penicillin resistance of the bacteria are separable from determinants that are responsible for the abnormal cell wall composition that often accompanies penicillin resistance in clinical strains of pneumococci. 相似文献
8.
Figueiredo A. Cristina Almendra M. João Barroso José G. Scheffer Johannes J. C. 《Biotechnology letters》1996,18(8):863-868
The transformation capacity of Achillea millefolium L. ssp. millefolium (yarrow) cell suspension cultures was investigated using geraniol (50mg/l) and borneol, menthol, thymol and farnesols (25mg/l) as substrates. Apart from converting these substrates into several biotransformation products, the cell suspension cultures were also able to glycosylate both the substrates and the biotransformation products. aa]Key Words bb]Achillea millefolium L. ssp. millefolium bb]Yarrow bb]Compositae bb]Biotransformation bb]Glycosylation bb]Geraniol bb]Borneol bb]Menthol bb]Thymol bb]Farnesols 相似文献
9.
Large DNA inversions caused by an intrachromosomal recombination between homologous regions located in intron 22 and 5 of the factor VIII gene have recently been identified in patients with severe haemophilia A. To evaluate better the prevalence of this large inversion and to estimate the overall sensitivity of the Southern blot/hybridization method we analysed the factor VIII gene of 49 unrelated patients with severe haemophilia A. All patients were screened for the inversion mutation, TaqI site mutations, and deletions. Mutations were identified in 31 (63%) patients, and comprised 24 large inversions, 4 partial deletions, and 3 point mutations. Three different haplotypes were characterised in the patients presenting the inversion mutation, confirming its independent origin. Two novel deletions are reported: a large one spanning from intron 14 to intron 22 and a deletion of 86 bp comprising the 3 region of exon 1 and 39–41 bp of intron 1. DNA sequencing of the deletion junction showed no significant homology between normal 5 and 3 sequences around the breakpoints. A novel missense mutation is also reported: CGAGGA, Arg-2209 to Gly. These results confirm that the inversion mutation is the most common cause of severe haemophilia A and indicate that the Southern blot/hybridization assay should be used as the first method for screening of mutations in severe haemophilia A. 相似文献
10.
Gisela M. Figueiredo Hermógenes F. Leitão-Filho Alpina Begossi 《Human ecology: an interdisciplinary journal》1993,21(4):419-430
Local plants are a very important resource for the community of Gamboa, located at Itacuruçá Island, Sepetiba Bay, State of Rio de Janeiro, Brazil Ninety species of plants, belonging to 40 families, are used for a variety of purposes, such as food, construction, handicraft, and medicine. In a survey medicinal uses for plants were the most quoted by the community. Uses of medicinal plants within Gamboa and with other coastal communities are analyzed using diversity indices. Use by different categories of people based on sex, age, and economic activity was compared and significant differences were found among the groups compared, except for economic categories (fishermen and non-fishermen). The theory of island biogeography is shown to be useful for analyzing different levels of resource uses on different islands. 相似文献