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141.
142.
The aim of this study was to investigate whether there were differences in the genetic variability and rate and velocity of
the seed germination produced by Psychotria tenuinervis located at anthropogenic edges, natural edges, and in the forest interior. The populations of P. tenuinervis showed no differences in genetic variability or structure among the three habitats. There was, however, an indication of inbreeding,
which was significantly higher in natural edges than in anthropogenic edges and the forest interior. Within-habitat variation
was considerable, but there were no differences in seed mass or rate and velocity of germination among the three habitats.
These results suggest that seed characteristics were not influenced by the genetic pattern of P. tenuinervis and that other characteristics of the forest fragment, such as gaps, edge age, and type of matrix exert more influence on
seed mass and germination than the distance from the edges. 相似文献
143.
Lívia Santos Lima Karina Peres Gramacho José Luis Pires Didier Clement Uilson Vanderlei Lopes Nicolas Carels Abelmon da Silva Gesteira Fernanda Amato Gaiotto Júlio Cézar de Mattos Cascardo Fabienne Micheli 《Tree Genetics & Genomes》2010,6(5):663-676
In this study, we report results of the detection and analysis of SSR markers derived of cacao–Moniliophthora perniciosa expressed sequence tags (ESTs) in relation to cacao resistance to witches’ broom disease (WBD), and we compare the polymorphism
of those ESTs (EST-simple sequence repeat (SSR)) with classical neutral SSR markers. A total of 3,487 ESTs was used in this
investigation. SSRs were identified in 430 sequences: 277 from the resistant genotype TSH 1188 and 153 from the susceptible
one Catongo, totalizing 505 EST-SSRs with three types of motifs: dinucleotides (72.1%), trinucleotides (27.3%), and tetranucleotides
(0.6%). EST-SSRs were classified into 16 main categories; most of the EST-SSRs belonged to “Unknown function” and “No homology”
categories (45.82%). A high frequency of SSRs was found in the 5’UTR and in the ORF (about 27%) and a low frequency was observed
in the 3’UTR (about 8%). Forty-nine EST-SSR primers were designed and evaluated in 21 cacao accessions, 12 revealed polymorphism,
having 47 alleles in total, with an average of 3.92 alleles per locus. On the other hand, the 11 genomic SSR markers revealed
a total of 47 alleles, with an average of 5.22 alleles per locus. The association of EST-SSR with the genomic SSR enhanced
the analysis of genetic distance among the genotypes. Among the 12 polymorphic EST-SSR markers, two were mapped on the F2 Sca 6 × ICS 1 population reference for WBD resistance. 相似文献
144.
145.
Marcelo dos Santos Guerra 《Plant Systematics and Evolution》1989,168(1-2):83-86
Azima tetracantha has an asymmetrical karyotype with large chromosomes and a large amount of heterochromatin. The haploid number (n = 11) may represent the base number of the family. However, a possible secondary origin of this base number is also considered. 相似文献
146.
Evaluation of cross-sectional geometry and mass density distributions of humans and laboratory animals using computerized tomography 总被引:1,自引:0,他引:1
The purpose of this study was to determine the cross-sectional geometry and mass density distribution of a young porcine subject using the X-ray computerized tomographic (CT) method and to perform a comparative study of anatomical features of this subject and a 3 yr old female child specimen. The cross-sectional CT scans of the porcine subject were obtained at 1 cm intervals. The outlines of each cross section and of selected anatomical components within each section were obtained by standard picture processing techniques. The mass and inertia tensor for each cross section and for each anatomical structure in a section were computed based on the CT numbers. The porcine subject was then sacrificed, frozen, sectioned and photographed. These sectional photographs were then compared with those obtained from the CT method. Tabulated cross-sectional mass and inertia tensor obtained from CT scans of the porcine subject were also used to compare with similar results derived from previously completed CT scans of the 3 yr old female child specimen. In particular, the comparisons were made on the location of the center of gravity and the inertia tensor in the head, neck, head and neck and cervical spine regions. Some immediate applications of this data are inputs to finite element models, lumped parameter biodynamic models, computer simulation of vehicle crash victims, and dummy design. 相似文献
147.
A. Ruiz A. Fontdevila M. Santos M. Seoane E. Torroja 《Evolution; international journal of organic evolution》1986,40(4):740-755
The pattern of selection acting in nature on the chromosomal polymorphism of the cactophilic species Drosophila buzzatii was investigated by comparing inversion and karyotypic frequencies through four different life-cycle stages: adult males, eggs, third-instar larvae, and immature adults. All population samples were obtained in June 1981 at an old Opuntia ficus-indica plantation near Carboneras, Spain. The analysis rests on several assumptions which are explicitly set forth and discussed. The results, if these assumptions prove true, indicate strong directional selection for larval viability acting on the second-chromosome karyotypes and also suggest selective differences in fecundity and longevity. Heterotic selection, however, cannot be ruled out for other fitness components such as male mating success. This kind of selection could be operating on the fourth-chromosome polymorphism as well. Some gene arrangements showed significant and opposite changes in frequency at different parts of the life cycle, thus demonstrating endocyclic selection. 相似文献
148.
Sergio Luiz Montego Ferreira Junior Elis Regina Dalla Costa Paula Gon?alves dos Santos Harrison Magdinier Gomes Marcia Susana Nunes Silva Leonardo Souza Esteves Martha Maria Oliveira Raquel de Abreu Maschmann Afranio Lineu Kritski Philip Noel Suffys Maria Lucia Rosa Rossetti 《Memórias do Instituto Oswaldo Cruz》2014,109(3):307-314
Drug-resistant tuberculosis (TB) threatens global TB control and is a major public
health concern in several countries. We therefore developed a multiplex assay
(LINE-TB/MDR) that is able to identify the most frequent mutations related to
rifampicin (RMP) and isoniazid (INH) resistance. The assay is based on multiplex
polymerase chain reaction, membrane hybridisation and colorimetric detection
targeting of rpoB and katG genes, as well as the
inhA promoter, which are all known to carry specific mutations
associated with multidrug-resistant TB (MDR-TB). The assay was validated on a
reference panel of 108 M. tuberculosis isolates that were characterised by the
proportion method and by DNA sequencing of the targets. When comparing the
performance of LINE-TB/MDR with DNA sequencing, the sensitivity, specificity and
agreement were 100%, 100% and 100%, respectively, for RMP and 77.6%, 90.6% and 88.9%,
respectively, for INH. Using drug sensibility testing as a reference standard, the
performance of LINE-TB/MDR regarding sensitivity, specificity and agreement was 100%,
100% and 100% (95%), respectively, for RMP and 77%, 100% and 88.7% (82.2-95.1),
respectively, for INH. LINE-TB/MDR was compared with GenoType MTBDRplus for 65
isolates, resulting in an agreement of 93.6% (86.7-97.5) for RIF and 87.4%
(84.3-96.2) for INH. LINE-TB/MDR warrants further clinical validation and may be an
affordable alternative for MDR-TB diagnosis. 相似文献
149.
150.
Joana Vindeirinho Gabriel N. Costa Mariana B. Correia Cláudia Cavadas Paulo F. Santos 《PloS one》2013,8(6)
The early stages of diabetic retinopathy (DR) are characterized by alterations similar to neurodegenerative and inflammatory conditions such as increased neural apoptosis, microglial cell activation and amplified production of pro-inflammatory cytokines. Adenosine regulates several physiological functions by stimulating four subtypes of receptors, A1AR, A2AAR, A2BAR, and A3AR. Although the adenosinergic signaling system is affected by diabetes in several tissues, it is unknown whether diabetic conditions in the retina can also affect it. Adenosine delivers potent suppressive effects on virtually all cells of the immune system, but its potential role in the context of DR has yet to be studied in full. In this study, we used primary mixed cultures of rat retinal cells exposed to high glucose conditions, to mimic hyperglycemia, and a streptozotocin rat model of type 1 diabetes to determine the effect diabetes/hyperglycemia have on the expression and protein levels of adenosine receptors and of the enzymes adenosine deaminase and adenosine kinase. We found elevated mRNA and protein levels of A1AR and A2AAR, in retinal cell cultures under high glucose conditions and a transient increase in the levels of the same receptors in diabetic retinas. Adenosine deaminase and adenosine kinase expression and protein levels showed a significant decrease in diabetic retinas 30 days after diabetes induction. An enzymatic assay performed in retinal cell cultures revealed a marked decrease in the activity of adenosine deaminase under high glucose conditions. We also found an increase in extracellular adenosine levels accompanied by a decrease in intracellular levels when retinal cells were subjected to high glucose conditions. In conclusion, this study shows that several components of the retinal adenosinergic system are affected by diabetes and high glucose conditions, and the modulation observed may uncover a possible mechanism for the alleviation of the inflammatory and excitotoxic conditions observed in diabetic retinas. 相似文献