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231.
Soraia A. C. Jorge Maria Concepcion de la Hera Angela M. M. Spina João Renato R. Pinho Carlos F. M. Menck 《Biotechnology letters》1995,17(12):1285-1290
Summary We have constructed a recombinant SV40-based vector carrying the S gene coding for the hepatitis B virus surface antigen (HBsAg). This vector replicates as an episome in monkey COS7 cells, producing high levels of hepatitis B virus surface antigen (HBsAg), which is liberated in the cell medium, probably as a membrane vesicule. The vector also carries the SV40-late genes and produces recombinant viruses. These viruses were used to infect fresh cell culture, with detection of HBsAg in the medium. Thus, this virus vector can efficiently transduce the gene for HBsAg. 相似文献
232.
A comparison of two methods for constructing evolutionary distances from a weighted contribution of transition and transversion differences 总被引:3,自引:3,他引:0
Since the initial work of Jukes and Cantor (1969), a number of procedures
have been developed to estimate the expected number of nucleotide
substitutions corresponding to a given observed level of nucleotide
differentiation assuming particular evolutionary models. Unlike the
proportion of different sites, the expected number of substitutions that
would have occurred grows linearly with time and therefore has had great
appeal as an evolutionary distance. Recently, however, a number of authors
have tried to develop improved statistical approaches for generating and
evaluating evolutionary distances (Schoniger and von Haeseler 1993;
Goldstein and Polock 1994; Tajima and Takezaki 1994). These studies clearly
show that the estimated number of nucleotide substitutions is generally not
the best estimator for use in reconstruction of phylogenetic relationships.
The reason for this is that there is often a large error associated with
the estimation of this number. Therefore, even though its expectation is
correct (i.e., on average the expected number of substitutions is
proportional to time- -but see Tajima 1993), it is not expected to be as
useful as estimators designed to have a lower variance.
相似文献
233.
234.
Thaís Peres Câmara Letícia Pinho Gomes Rosaline Rocha Lunardi Paula Cristina de Souza Souto Adriana Degrossoli Wagner Welber Arrais-Silva 《Journal of Asia》2018,21(4):1389-1392
The bloodsucking bug Triatoma williami is the main vector of Trypanosoma cruzi, the etiological agent of Chagas disease in State of Mato Grosso, Brazil. It occurs in sylvatic areas of Brazilian savanna with often records of adult specimens in domestic and peridomestic habitats. We describe, for the first time, the reproductive parameters of T. williami females such as fecundity, fertility and lifespan. We also evaluate whether mating and nourishment status of females of T. williami may modulate the reproductive parameters. As a result, the presence of male corroborated to increase female lifespan from 5.14±1,77 to 34.57±10,86 weeks. The oviposition rate in mated female increased 275% when we compared to the fecundity values in unmated females. Finally, our results indicate that mating is crucial to improve lifespan and fecundity of T. williami females. This characteristic may be related to the environmental conditions under T. williami develops, because the sylvatic ecotopes form small scattered colonies with infrequent access to blood sources. 相似文献
235.
Piqueira JR Fagali GM de Pinho M Sanches RF Del-Ben CM Zuardi AW 《Journal of theoretical biology》2007,247(1):182-185
The present study is a trial on expressing the whole state of a psychiatric ward as a linear combination of base states in a Hilbert space. Real data were collected by observing the behavior of the patients from the psychiatric ward of the Clinical Hospital from Faculdade de Medicina de Ribeir?o Preto for 12 days and, according to standard procedures, 18 behavioral parameters were daily measured for each patient. The whole data set was analyzed and, by taking the standard grades as eigenstates, the state of the ward was daily expressed by a linear combination of them, allowing the estimation of state transition matrices and of the quantum variability measure. Coefficients of the linear combination can be interpreted as square roots of probabilities and informational entropy is associated to each state resulting in the classical variability measure. Temporal evolutions of the classical and quantum variability measures are plotted trying to relate them to the behavioral state of the whole ward. 相似文献
236.
Oliveira EC Moura MR Silva VA Peixoto CA Saraiva KL de Sá MJ Douglas RH de Pinho Marques A 《Theriogenology》2007,68(2):137-145
The objective of the present study was to evaluate, by light and transmission electron microscopy, the efficacy of a single intratesticular injection of a novel zinc-based solution, as a contraceptive for male dogs. Fifteen mongrel dogs were assigned to three groups (five dogs/group). Group 1, the control group, which consisted of animals ranging from 8 mo to 4 yr, was injected with saline solution. Group 2, which consisted of animals ranging from 8 mo to 1 yr old and Group 3, animals ranging from 2 to 4 yr old, were injected with a zinc-based solution (0.2-1.0mL; volume based on testicular width). There were no histopathological changes detected in testes from control dogs. Histological examination of treated groups revealed degeneration, vacuolation, fewer germ cells, formation of multinucleated giant cells, and a lack of elongated spermatids in atrophic seminiferous tubules. Leydig cells had varying degrees of lipid degeneration and necrosis. The majority of seminiferous tubules in all zinc-treated dogs were lined only by Sertoli cells, which were vacuolated. Ultrastructure of testis of treated groups had degenerate Sertoli and Leydig cells, characterized by numerous mitochondria with the lack of a matrix and agglomeration of lysosomal bodies. The cytoplasm of elongated spermatids was characterized by tubules of hyperplastic and hypertrophic smooth endoplasmic reticulum and numerous Golgi apparati. Round spermatids in Golgi phase had lysis of acrosomal vesicles. The degree of histological changes suggested irreversibility. In conclusion, intratesticular injection of a zinc-based solution effectively impaired spermatogenesis. 相似文献
237.
Pleistocene climatic oscillations were a major force shaping genetic variability in many taxa. We analyse the relative effects of the ice ages across a latitudinal gradient in the Western Mediterranean region, testing two main predictions: (i) species with historical distributions in northern latitudes should have experienced greater loss of suitable habitat, resulting in higher extinction of historical lineages than species distributed in southern latitudes, where the effects of the ice ages were not as drastic. This would be reflected in the observation of lower diversity and number of differentiated lineages in northern areas. (ii) a signature of demographic expansion following the climate amelioration should be obvious in northern species, whereas in the south evidence of long-term effective population size stability should be observed. We used as models three species of wall lizards (Podarcis bocagei, Podarcis carbonelli and Podarcis vaucheri) that replace each other along the study area. We investigated the patterns of mitochondrial DNA diversity and subdivision and obtained demographic parameter estimates for each species. Our results suggest that P. bocagei, the northernmost species, bears low genetic diversity, a shallow coalescent history and marks of a demographic expansion. In contrast, P. vaucheri, the species with a southernmost distribution, shows deeper coalescence events, complex geographical substructure and no evidence for population growth. The species with an intermediate distribution, P. carbonelli, shows average levels of diversity, substructure and population growth. Taken together, these results conform to our main predictions and are explained by a differential influence of the ice ages on distinct latitudes. 相似文献
238.
Fabiana Martins de Paula Fernanda de Mello Malta Priscilla Duarte Marques Renata Barnabé Sitta Jo?o Renato Rebello Pinho Ronaldo César Borges Gryschek Pedro Paulo Chieffi 《Memórias do Instituto Oswaldo Cruz》2015,110(2):272-274
This study aimed to evaluate the use of conventional polymerase chain reaction (cPCR)
and real-time quantitative PCR (qPCR) in the diagnosis of human strongyloidiasis from
stool samples in tropical areas. Stool samples were collected from individuals and
were determined to be positive for Strongyloides stercoralis (group I), negative for
S. stercoralis (group II) and positive for other enteroparasite species (group III).
DNA specific to S. stercoralis was found in 76.7% of group I samples by cPCR and in
90% of group I samples by qPCR. The results show that molecular methods can be used
as alternative tools for detecting S. stercoralis in human stool samples in tropical
areas. 相似文献
239.
Freitas LS Freitas TP Silveira PC Rocha LG Pinho RA Streck EL 《Cell biology international》2007,31(5):482-488
Contusion injuries are a very common form of both athletic and non-athletic injury, that effect muscle function. Treatments to augment the normal repair and regeneration processes are important for a wide variety of patients. Therapeutic ultrasound has been claimed to promote tissue repair, especially by enhancing cell proliferation and protein synthesis. The present study aimed to investigate the effect of therapeutic pulsed ultrasound (TPU) on parameters of oxidative stress, namely thiobarbituric acid-reactive substances (TBARS), protein carbonyl content and the activities of antioxidant enzymes, catalase and superoxide dismutase (SOD), in skeletal muscle after injury. Wistar rats were submitted to an animal model of muscle (gastrocnemius) laceration. TPU was used once a day. One, three or five days after muscle laceration, the animals were killed by decapitation and oxidative stress parameters were evaluated. Serum CK levels were increased in muscle-injured animals, indicating that the laceration animal model was successful. TBARS were not altered after muscle injury, when compared to the sham group. Protein carbonyl content was increased after muscle laceration. Catalase and SOD activities were increased 1 day after muscle injury and not altered at days 3 and 5. TPU decreased TBARS levels after muscle laceration when compared to injured muscle animals without treatment. Protein carbonyl content evaluation presented similar results. It is tempting to speculate that TPU seems to protect the tissue from oxidative injury. TPU diminished catalase and SOD activities, especially on the first day following muscle laceration. 相似文献
240.
Polyglutamine expansion mutations in specific proteins underlie the pathogenesis of a group of progressive neurodegenerative disorders, including Huntington’s disease, spinal and bulbar muscular atrophy, dentatorubral-pallidoluysian atrophy, and several spinocerebellar ataxias. The different mutant proteins share ubiquitous expression and abnormal proteostasis, with misfolding and aggregation, but nevertheless evoke distinct patterns of neurodegeneration. This highlights the relevance of the full protein context where the polyglutamine expansion occurs and suggests different interactions with the cellular proteostasis machinery. Molecular chaperones are key elements of the proteostasis machinery and therapeutic targets for neurodegeneration. Here, we provide a focused review on Hsp90, Hsp70, and their co-chaperones, and how their genetic or pharmacological modulation affects the proteostasis and disease phenotypes in cellular and animal models of polyglutamine disorders. The emerging picture is that, in principle, Hsp70 modulation may be more amenable for long-term treatment by promoting a more selective clearance of mutant proteins than Hsp90 modulation, which may further decrease the necessary wild-type counterparts. It seems, nevertheless, unlikely that a single Hsp70 modulator will benefit all polyglutamine diseases. Indeed, available data, together with insights from effects on tau and alpha-synuclein in models of Alzheimer’s and Parkinson’s diseases, indicates that Hsp70 modulators may lead to different effects on the proteostasis of different mutant and wild-type client proteins. Future studies should include the further development of isoform selective inhibitors, namely to avoid off-target effects on Hsp in the mitochondria, and their characterization in distinct polyglutamine disease models to account for client protein-specific differences. 相似文献