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71.
José M. Icardo Wai P. Wong Elvira Colvee Filippo Garofalo Ai M. Loong Yuen K. Ip 《Journal of morphology》2011,272(7):769-779
We describe the microstructure of the alimentary canal of the juvenile lungfish Protopterus annectens. Following the oesophagus, the gut is formed by a long segment that extends down to the pyloric valve. This segment, classically named stomach, is lined by a transitional epithelium but lacks all characteristics of the vertebrate stomach. It has been defined here as the intestinal vestibule. The spiral valve is divided into a first large chamber, which contains mucosal ridges, and a second smooth portion. The entire spiral valve is lined with a pseudostratified columnar epithelium that contains approximately six cell types: enterocytes, goblet cells, ciliated cells, leukocytes, dark pigment cells, and vascular cells. Enterocytes and goblet cells show a high number of cytoplasmic vacuoles. The number and size of the vacuoles, and the number of ciliated cells, decreases from the anterior toward the posterior end, suggesting that most of the digestive processes take place in the anterior part of the spiral valve. The epithelium overlies a lamina propria in the first large chamber and a vascular plexus in the smooth portion. The cloaca has a thick muscular wall covered by a transitional epithelium. An extensive lymphatic system formed by capillaries and lymphatic micropumps is present along the entire wall of the alimentary canal. J. Morphol., 2011. © 2011 Wiley‐Liss, Inc. 相似文献
72.
Khor B Bredemeyer AL Huang CY Turnbull IR Evans R Maggi LB White JM Walker LM Carnes K Hess RA Sleckman BP 《Molecular and cellular biology》2006,26(8):2999-3007
The PA200 proteasome activator is a broadly expressed nuclear protein. Although how PA200 normally functions is not fully understood, it has been suggested to be involved in the repair of DNA double-strand breaks (DSBs). The PA200 gene (Psme4) is composed of 45 coding exons spanning 108 kb on mouse chromosome 11. We generated a PA200 null allele (PA200(Delta)) through Cre-loxP-mediated interchromosomal recombination after targeting loxP sites at either end of the locus. PA200(Delta/Delta) mice are viable and have no obvious developmental abnormalities. Both lymphocyte development and immunoglobulin class switching, which rely on the generation and repair of DNA DSBs, are unperturbed in PA200(Delta/Delta) mice. Additionally, PA200(Delta/Delta) embryonic stem cells do not exhibit increased sensitivity to either ionizing radiation or bleomycin. Thus, PA200 is not essential for the repair of DNA DSBs generated in these settings. Notably, loss of PA200 led to a marked reduction in male, but not female, fertility. This was due to defects in spermatogenesis observed in meiotic spermatocytes and during the maturation of postmeiotic haploid spermatids. Thus, PA200 serves an important nonredundant function during spermatogenesis, suggesting that the efficient generation of male gametes has distinct protein metabolic requirements. 相似文献
73.
74.
Swee Loong Khor Darren Delai Sun Yajuan Liu James O. Leckie 《Process Biochemistry》2007,42(12):1641-1648
This study was conducted to investigate the development and extracellular polymeric substances (EPS) distribution in biofouling layer and biofouling effect on permeate quality. The experimental results suggested that formation of biofouling layer was started by the attachment of polysaccharides and formed a biogel like layer on top of membrane surface (adhesive attachment). It further induced the attachment of protein, polysaccharides and bioparticles, and formed cake layer (cohesive attachment). As evidenced in SEM photos and permeates quality, the formed biofouling layer had changed the properties of membrane surface such as the pore and porosity, and hence produce the better permeates quality. A great enhancement of rejection performance occurred at the early filtration period, and followed by a slight enhancement in rejection throughout the entire filtration. This enhancement of rejection performance by biofouling layer can be mathematically expressed by the logarithm function with the degree of membrane fouling. 相似文献
75.
Kelvin Kian Loong Wong 《PloS one》2010,5(4)
A new treatment to determine the Pareto-optimal outcome for a non-zero-sum game is presented. An equilibrium point for any game is defined here as a set of strategy choices for the players, such that no change in the choice of any single player will increase the overall payoff of all the players. Determining equilibrium for multi-player games is a complex problem. An intuitive conceptual tool for reducing the complexity, via the idea of spatially representing strategy options in the bargaining problem is proposed. Based on this geometry, an equilibrium condition is established such that the product of their gains over what each receives is maximal. The geometrical analysis of a cooperative bargaining game provides an example for solving multi-player and non-zero-sum games efficiently. 相似文献
76.
Automatic target recognition that relies on rapid feature extraction of real-time target from photo-realistic imaging will enable efficient identification of target patterns. To achieve this objective, Cross-plots of binary patterns are explored as potential signatures for the observed target by high-speed capture of the crucial spatial features using minimal computational resources. Target recognition was implemented based on the proposed pattern recognition concept and tested rigorously for its precision and recall performance. We conclude that Cross-plotting is able to produce a digital fingerprint of a target that correlates efficiently and effectively to signatures of patterns having its identity in a target repository. 相似文献
77.
78.
Background
Heterocellular hereditary persistence of fetal hemoglobin (HPFH) is a common multifactorial trait characterized by a modest increase of fetal hemoglobin levels in adults. We previously localized a Quantitative Trait Locus for HPFH in an extensive Asian-Indian kindred to chromosome 6q23. As part of the strategy of positional cloning and a means towards identification of the specific genetic alteration in this family, a thorough annotation of the candidate interval based on a strategy ofin silico/ wet biology approach with comparative genomics was conducted. 相似文献79.
K. H. Prakash R. Kumar C. P. Ooi T. Sritharan P. Cheang K. A. Khor 《Molecular & cellular biomechanics : MCB》2006,3(4):177-178
This article has no abstract. 相似文献
80.
Isolates of Alternaria alternata collected from a field site which had previously been treated with the dicarboximide fungicide iprodione were found to demonstrate a high level of resistance to iprodione and the phenylpyrrole fungicide, fludioxonil in plate assays. In order to determine the genetic basis for this fungicide resistance a partial length clone of a two-component histidine kinase (HK) was isolated from genomic DNA of a fungicide-sensitive A. alternata isolate using degenerate primers by PCR. Analysis of the AaHK1 gene structure indicates the presence of six 90 amino acid repeat domains upstream of a kinase domain as found in the homologous HK genes from other fungal species. Comparison of nucleic acid sequences from the fungicide-sensitive and fungicide-resistant A. alternata isolates confirmed the presence of mutations leading to premature termination of the translated HK protein. The possible role of the two-component HK in the development of dicarboximide resistance in A. alternata is discussed. 相似文献