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81.
Karina Vanessa Hmeljevski Ademir Reis Tiago Montagna Maurício Sedrez dos Reis 《Conservation Genetics》2011,12(3):761-769
Dyckia ibiramensis is a naturally rare, endemic and threatened bromeliad which occurs naturally on 4 km of rocky river outcroppings in Southern
Brazil. For this study, subpopulations of the species were characterized based on size and genetics, to compile information
for in situ and ex situ conservation strategies. A census of the rosettes was undertaken for each subpopulation and seven allozyme polymorphic loci
were used to estimate genetic diversity and structure of adults and offspring and assess the mating system. In general, the
subpopulations were small and most of the rosettes were aggregated into clumps. The species showed a high genetic diversity
([^(H)]e = 0.219 \hat{H}_{e} = 0.219 ) and significant fixation index ([^(f)] = 0.642, \hat{f} = 0.642,
P ≤ 0.05). The estimate of differentiation among all adult subpopulations indicate pronounced genetic structure ([^(G)]¢ST = 0.674 \hat{G}^{\prime}_{ST} = 0.674 ). D. ibiramensis has a mixed mating system and multilocus outcrossing rates [^(t)]m \hat{t}_{m} were variable between subpopulations. This study demonstrates the importance of in situ preservation of all subpopulations
for the maintenance of species diversity. For effective ex situ conservation, it would be necessary to collect seeds from 52 to 99 seed-rosettes, depending on the target population. 相似文献
82.
Sequence of chicken c beta 7 tubulin. Analysis of a complete set of vertebrate beta-tubulin isotypes 总被引:6,自引:0,他引:6
In chicken, beta-tubulin is encoded by a family of seven genes. We have now isolated and sequenced overlapping cDNA clones corresponding to gene c beta 7 (previously designated c beta 4'), the only chicken beta-tubulin not previously characterized. The inferred amino acid sequence of c beta 7 tubulin is identical with the class I beta-tubulin isotype found in human, mouse and rat. Moreover, c beta 7 is highly expressed in almost all tissue and cell types in chicken, a pattern similar to those of the genes for class I beta-tubulin isotypes in other vertebrates. Comparison of the complete family of chicken beta-tubulin gene sequences reveals that the heterogeneity of beta-tubulin polypeptides encoded in a higher eukaryote is confined to six distinct beta-tubulin isotypes. Five of these are members of evolutionarily conserved isotypic classes (I to V), whereas the sixth represents a divergent erythroid-specific tubulin whose sequence has not been conserved. 相似文献
83.
Paula Zaghetto Almeida Josana Maria Messias Marita Gimenez Pereira Vanessa Elisa Pinheiro Lummy Maria Oliveira Monteiro Paulo Ricardo Heinen 《Biocatalysis and Biotransformation》2018,36(5):389-395
Starch has great importance in human diet, since it is a heteropolymer of plants, mainly found in roots, as potato, cassava and arrowroots. This carbohydrate is composed by a highly-branched chain: amylopectin; and a linear chain: amylose. The proportion between the chains varies according to the botanical source. Starch hydrolysis is catalyzed by enzymes of the amilolytic system, named amylases. Among the various enzymes of this system, the glucoamylases (EC 3.2.1.3 glucan 1,4-alpha-glucosidases) are the majority because they hydrolyze the glycosidic linkages at the end of starch chains releasing glucose monomers. In this work, a glucoamylase secreted in the culture medium, by the ascomycete Aspergillus brasiliensis, was immobilized in Dietilaminoetil Sepharose-Polyethylene Glycol (DEAE-PEG), since immobilized biocatalysts are more stable in long periods of hydrolysis, and can be recovered from the final product and reused for several cycles. Glucoamylase immobilization has shown great thermal stability improvement over the soluble enzyme, reaching 66% more activity after 6?h at 60?°C, and 68% of the activity after 10 hydrolysis cycles. A simplex centroid experimental mixture design was applied as a tool to characterize the affinity of the immobilized enzyme for different starchy substrates. In assays containing several proportions of amylose, amylopectin and starch, the glucoamylase from A. brasiliensis mainly hydrolyzed the amylopectin chains, showing to have preference by branched substrates. 相似文献
84.
85.
Marcos Valerio Garcia Vinicius da Silva Rodrigues Antônio Carlos Monteiro Lucas Detogni Simi Leandro de Oliveira Souza Higa Maria Marlene Martins Nancy Prette Dinalva Alves Mochi Renato Andreotti Matias Pablo Juan Szabó 《Experimental & applied acarology》2018,76(4):507-512
Amblyomma parvum Aragão (Acari: Ixodidae) is a tick species found with wide distribution in the Neotropical region. Even though it is a wildlife-related tick, it is also a frequent parasite of domestic animals, is aggressive to human beings and may harbor pathogenic microorganisms. Therefore, it is a target species for control on domestic animals, particularly those at the rural–wildlife interface. Herein, the efficacy of two isolates (E9 and IBCB 425) of an entomopathogenic fungus, Metarhizium anisopliae sensu lato, already evaluated for ticks that parasitize domestic animals, was tested against unfed A. parvum adults. Both isolates displayed high acaricidal efficacy after immersion in fungal conidial suspensions for 5 min. Isolate E9 killed all ticks by the 7th day post-treatment, and isolate IBCB 425 did so by the 11th day. Tick mortality of 80 and 90% was achieved as early as the 3rd and 4th days, respectively, with both treatments. Thus, if a commercial M. anisopliae s.l. acaricide against domestic animal ticks is developed, it would also be effective against A. parvum. 相似文献
86.
Thdia Evelyn de Araújo Iliana Claudia Balga Milin Guilherme de Souza Rafaela Jos da Silva Alessandra Monteiro Rosini Pmela Mendona Guirelli Priscila Silva Franco Bellisa Freitas Barbosa Eloisa Amlia Vieira Ferro Idessania Nazareth da Costa 《Cell biology international》2020,44(1):36-50
During pregnancy, the placenta regulates the transfer of oxygen, nutrients, and residual products between the maternal and fetal bloodstreams and is a key determinant of fetal exposure to xenobiotics from the mother. To study the disposition of substances through the placenta, various experimental models are used, especially the perfused placenta, placental villi explants, and cell lineage models. In this context, nanotechnology, an area of study that is on the rise, enables the creation of particles on nanometric scales capable of releasing drugs aimed at specific tissues. An important reason for furthering the studies on transplacental transfer is to explore the potential of nanoparticles (NPs), in new delivery strategies for drugs that are specifically aimed at the mother, the placenta, or the fetus and that involve less toxicity. Due to the fact that the placental barrier is essential for the interaction between the maternal and fetal organisms as well as the possibility of NPs being used in the treatment of various pathologies, the aim of this review is to present the main experimental models used in studying the maternal–fetal interaction and the action of NPs in the placental environment. 相似文献
87.
88.
Matheus D. Baldissera Camila B. Oliveira Carine E. P. Zimmermann Aline A. Boligon Margareth Linde Athayde Leandro P. Bolzan Rodrigo de A. Vaucher Janio M. Santurio Michele R. Sagrillo Aleksandro Schafer da Silva Silvia G. Monteiro 《The Korean journal of parasitology》2014,52(3):311-315
The aim of this study was to verify the trypanocidal effectiveness of aqueous, methanolic, and ethanolic extracts of Achyrocline satureioides against Trypanosoma evansi in vitro. A. satureioides extracts, known as macela, were used on trypomastigotes at different concentrations (1, 5, 10, 50, 100, 500, and 1,000 µg/ml) and exposure times (0, 1, 3, 6, and 9 hr). A dose-dependent effect was observed when the 3 extracts were tested. The concentrations of 1, 5, and 10 µg/ml were not able to kill trypomastigotes until 3 hr after exposure, and the highest concentrations (500 and 1,000 µg/ml) were able to kill all trypomastigotes after 1 hr. When the time of exposure was increased up to 9 hr, the concentrations at 50 and 100 µg/ml were 100% effective to 3 extracts. The chemical analysis of the extracts revealed the presence of flavonoids, a trypanocidal compound already described. Based on the results, we can conclude that the A. satureioides extracts exhibit trypanocidal effects. 相似文献
89.
90.
Carlos Rafael Borges Mendes Raul Rodrigo Costa Afonso Ferreira Bruno Jesus Virginia Maria Tavano Tiago Segabinazzi Dotto Miguel Costa Leal Rodrigo Kerr Carolina Antuarte Islabão Andréa de Oliveira da Rocha Franco Mauricio M. Mata Carlos Alberto Eiras Garcia Eduardo Resende Secchi 《Global Change Biology》2023,29(7):1791-1808
The western Antarctic Peninsula (WAP) is a climatically sensitive region where foundational changes at the basis of the food web have been recorded; cryptophytes are gradually outgrowing diatoms together with a decreased size spectrum of the phytoplankton community. Based on a 11-year (2008–2018) in-situ dataset, we demonstrate a strong coupling between biomass accumulation of cryptophytes, summer upper ocean stability, and the mixed layer depth. Our results shed light on the environmental conditions favoring the cryptophyte success in coastal regions of the WAP, especially during situations of shallower mixed layers associated with lower diatom biomass, which evidences a clear competition or niche segregation between diatoms and cryptophytes. We also unravel the cryptophyte photo-physiological niche by exploring its capacity to thrive under high light stress normally found in confined stratified upper layers. Such conditions are becoming more frequent in the Antarctic coastal waters and will likely have significant future implications at various levels of the marine food web. The competitive advantage of cryptophytes in environments with significant light level fluctuations was supported by laboratory experiments that revealed a high flexibility of cryptophytes to grow in different light conditions driven by a fast photo-regulating response. All tested physiological parameters support the hypothesis that cryptophytes are highly flexible regarding their growing light conditions and extremely efficient in rapidly photo-regulating changes to environmental light levels. This plasticity would give them a competitive advantage in exploiting an ecological niche where light levels fluctuate quickly. These findings provide new insights on niche separation between diatoms and cryptophytes, which is vital for a thorough understanding of the WAP marine ecosystem. 相似文献