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271.
272.
Construction of a recombinant BHV-1 expressing the VP1 gene of foot and mouth disease virus and its immunogenicity in a rabbit model 总被引:1,自引:0,他引:1
Xian-Gang Ren Fei Xue Yuan-Mao Zhu Guang-Zhi Tong Yan-Hui Wang Jun-Ke Feng Hong-Fei Shi Yu-Ran Gao 《Biotechnology letters》2009,31(8):1159-1165
Foot-and-mouth disease (FMD) and infectious bovine rhinotracheitis (IBR) are two important infectious diseases of cattle.
Using bovine herpesvirus type 1 (BHV-1) as a gene delivery vector for development of live-viral vaccines has gained widespread
interest. In this study, a recombinant BHV-1 was constructed by inserting the synthetic FMDV (O/China/99) VP1 gene in the
the gE locus of BHV-1 genome under the control of immediately early gene promoter of human cytomegalovirus (phIE CMV) and
bovine growth hormone polyadenylation (BGH polyA) signal. After homologous recombination and plaque purification, a recombinant
virus named BHV-1/gE−/VP1 was acquired and identified. The immunogenicity was confirmed in a rabbit model by virus neutralization test and enzyme-linked
immunosorbent assay (ELISA). The result indicated that the BHV-1/gE−/VP1 has the potential for being developed as a bivalent vaccine for FMD and IBR. 相似文献
273.
Maria A. Diuk‐Wasser Gwenaël Vourc'h Paul Cislo Anne Gatewood Hoen Forrest Melton Sarah A. Hamer Michelle Rowland Roberto Cortinas Graham J. Hickling Jean I. Tsao Alan G. Barbour Uriel Kitron Joseph Piesman Durland Fish 《Global Ecology and Biogeography》2010,19(4):504-514
Aim Ixodes scapularis is the most important vector of human tick‐borne pathogens in the United States, which include the agents of Lyme disease, human babesiosis and human anaplasmosis, among others. The density of host‐seeking I. scapularis nymphs is an important component of human risk for acquiring Borrelia burgdorferi, the aetiological agent of Lyme disease. In this study we used climate and field sampling data to generate a predictive map of the density of host‐seeking I. scapularis nymphs that can be used by the public, physicians and public health agencies to assist with the diagnosis and reporting of disease, and to better target disease prevention and control efforts. Location Eastern United States of America. Methods We sampled host‐seeking I. scapularis nymphs in 304 locations uniformly distributed east of the 100th meridian between 2004 and 2006. Between May and September, 1000 m2 were drag sampled three to six times per site. We developed a zero‐inflated negative binomial model to predict the density of host‐seeking I. scapularis nymphs based on altitude, interpolated weather station and remotely sensed data. Results Variables that had the strongest relationship with nymphal density were altitude, monthly mean vapour pressure deficit and spatial autocorrelation. Forest fragmentation and soil texture were not predictive. The best‐fit model identified two main foci – the north‐east and upper Midwest – and predicted the presence and absence of I. scapularis nymphs with 82% accuracy, with 89% sensitivity and 82% specificity. Areas of concordance and discordance with previous studies were discussed. Areas with high predicted but low observed densities of host‐seeking nymphs were identified as potential expansion fronts. Main conclusions This model is unique in its extensive and unbiased field sampling effort, allowing for an accurate delineation of the density of host‐seeking I. scapularis nymphs, an important component of human risk of infection for B. burgdorferi and other I. scapularis‐borne pathogens. 相似文献
274.
Silurian calcispheres (Calcitarcha) of Gotland (Sweden): Comparisons with calcareous dinoflagellates
Scanning electron microscope examinations of polished and etched surfaces of sediments from the Silurian carbonate platform of Gotland, Sweden, revealed the presence of numerous, morphologically diverse “calcispheres” (Calcitarcha). Some of these spherical calcareous microfossils display wall structures that are surprisingly similar to those of calcareous dinoflagellate cysts. In analogy to the interpretation of the biological affinities of Palaeozoic acritarchs as cysts of organisms that might have been the ancestors of organic-walled dinoflagellates, the Calcitarcha from Gotland can be compared and may possibly be related to organisms that may have been the ancestors of calcareous cyst-producing dinoflagellates that so far have not been observed before the Late Jurassic. 相似文献
275.
276.
Remote homology detection refers to the detection of structural homology in proteins when there is little or no sequence similarity. In this article, we present a remote homolog detection method called SVM-HMMSTR that overcomes the reliance on detectable sequence similarity by transforming the sequences into strings of hidden Markov states that represent local folding motif patterns. These state strings are transformed into fixed-dimension feature vectors for input to a support vector machine. Two sets of features are defined: an order-independent feature set that captures the amino acid and local structure composition; and an order-dependent feature set that captures the sequential ordering of the local structures. Tests using the Structural Classification of Proteins (SCOP) 1.53 data set show that the SVM-HMMSTR gives a significant improvement over several current methods. 相似文献
277.
Rodini CO Batista AC Dionísio TJ Santos CF Cunha FQ Lara VS 《Journal of molecular histology》2008,39(3):275-282
The immunopathologic and inflammatory mechanisms involved in periodontal disease (PD) include the participation of host resident,
inflammatory cells and chemical mediators. Metalloproteinases (MMPs) and nitric oxide (NO) play essential role in extracellular
matrix turnover of periodontal tissue destruction. In this study, by means of RT-PCR through semi-quantitative densitometric
scanning methods, the expression of MMPs -2 and -9 and inducible NO synthase (iNOS) was temporally and spatially investigated
during the destructive mechanisms of experimentally induced PD in rats. Samples from different periods were microscopically
analyzed and compared with the contralateral side (control). Our results showed significant expression of MMP-9 and iNOS in
tissues affected by PD, as compared with controls, three days after PD induction, simultaneously with the beginning of alveolar
bone loss. At 7 days post induction, only the MMP-9 mRNA presented a significantly higher expression, as compared with the
respective controls. Thus, in the rat ligature-induced PD, MMP-9 and iNOS might importantly participate in the early stages
of the disease, including inflammatory cell migration, tissue destruction and alveolar bone resorption. Also, we may suggest
that the exuberant presence of PMNs may be related to the important expression of iNOS and MMP-9 found at 3 days post induction. 相似文献
278.
Nitric oxide (NO) is a chemical weapon within the arsenal of immune cells, but is also generated endogenously by different bacteria. Pseudomonas aeruginosa are pathogens that contain an NO-generating nitrite (NO2−) reductase (NirS), and NO has been shown to influence their virulence. Interestingly, P. aeruginosa also contain NO dioxygenase (Fhp) and nitrate (NO3−) reductases, which together with NirS provide the potential for NO to be metabolically cycled (NO→NO3−→NO2−→NO). Deeper understanding of NO metabolism in P. aeruginosa will increase knowledge of its pathogenesis, and computational models have proven to be useful tools for the quantitative dissection of NO biochemical networks. Here we developed such a model for P. aeruginosa and confirmed its predictive accuracy with measurements of NO, O2, NO2−, and NO3− in mutant cultures devoid of Fhp or NorCB (NO reductase) activity. Using the model, we assessed whether NO was metabolically cycled in aerobic P. aeruginosa cultures. Calculated fluxes indicated a bottleneck at NO3−, which was relieved upon O2 depletion. As cell growth depleted dissolved O2 levels, NO3− was converted to NO2− at near-stoichiometric levels, whereas NO2− consumption did not coincide with NO or NO3− accumulation. Assimilatory NO2− reductase (NirBD) or NorCB activity could have prevented NO cycling, and experiments with ΔnirB, ΔnirS, and ΔnorC showed that NorCB was responsible for loss of flux from the cycle. Collectively, this work provides a computational tool to analyze NO metabolism in P. aeruginosa, and establishes that P. aeruginosa use NorCB to prevent metabolic cycling of NO. 相似文献
279.
Generalized estimating equations (GEE) are extension of generalized linear models (GLM) widely applied in longitudinal data analysis. GEE are also applied in spatial data analysis using geostatistics methods. In this paper, we advocate application of GEE for spatial lattice data by modeling the spatial working correlation matrix using the Moran's index and the spatial weight matrix. We present theoretical developments and results for simulated and actual data as well. For the former case, 1,000 samples of a random variable (response variable) defined in (0, 1) interval were generated using different values of the Moran's index. In addition, 1,000 samples of a binary and a continuous variable were also randomly generated as covariates. In each sample, three structures of spatial working correlation matrices were used while modeling: The independent, autoregressive, and the Toeplitz structure. Two measures were used to evaluate the performance of each of the spatial working correlation structures: the asymptotic relative efficiency and the working correlation selection criterions. The results showed that both measures indicated that the autoregressive spatial working correlation matrix proposed in this paper presents the best performance in general. For the actual data case, the proportion of small farmers who used improved maize varieties was considered as the response variable and a set of nine variables were used as covariates. Two structures of spatial working correlation matrices were used and the results showed consistence with those obtained in the simulation study. 相似文献
280.
Seiji Sonobe 《Journal of plant research》1996,109(4):437-448
Vacuoles in plant cells can be eliminated by centrifugation of protoplasts through a density gradient. In this review, properties
of evacuolated protoplasts, named ‘miniprotoplasts’, and the significant roles in plant cytoskeleton studies are described.
Miniprotoplasts, prepared from tobacco BY-2 cells whose cell-cycle had been synchronized at late anaphase, continued to divide
to form two daughter cells. In the presence of cytochalasin B cytokinetic cleavage was enhanced, suggesting a role of actin
filaments in plant cytokinesis. In the cytoplasmic extract of miniprotoplasts both tubulin and actin could be polymerized
to form microtubules (MTs) and actin filaments (AFs), respectively. A purification method for tubulin, actin and related proteins
was developed using the extract. To investigate the interaction between cortical microtubules and the plasma membrane, an
experimental system in which MTs were reconstructed on membrane ghosts was developed by combination of membrane ghosts and
the extract. 相似文献