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911.
Wang KW Lee KG Park TJ Lee YC Yang JW Kim do H Lee SJ Park JY 《Biotechnology and bioengineering》2012,109(1):289-294
We developed a novel one-pot synthetic strategy for preparing monodisperse polyethylene glycol diacrylate (PEGDA) microdroplets via organoclay-assisted interfacial polymerization approach for Escherichia coli encapsulation. Based on the mechanism of spontaneous and rapid polymerization of PEGDA precursor solution with Mg-organoclay, the prepared PEGDA microdroplets have uniform size and fine round shape, with size range of 74-118 μm. The size of microdroplets can be controlled through the changing continuous phase flow rate. Organoclay-assisted polymerization method provides a unique environment to produce non-toxic ways of fabricating microorganism encapsulated microdroplets and to prohibit microdroplets merge during the processes. Furthermore, we successfully carried out to entrap E. coli inside of the PEGDA microdroplets. E. coli expressing a green fluorescent protein shows a good viability inside the PEGDA microdroplets. The in situ microfluidic synthetic method provides a novel approach for the preparation of monodisperse PEGDA microdroplets via a one-pot route. 相似文献
912.
Pseudomonas spp. have shown characteristics of efficiently metabolizing environmental pollutants and also producing exopolysaccharides known as biofilms. Here we present the draft genome sequence of Pseudomonas sp. strain PAMC 25886, which was isolated from glacier cryoconite in the Alps mountain permafrost region and which may provide further insight into biodegradative and/or biofilm-producing mechanisms in a cold environment. 相似文献
913.
Patrick G. T. Walker Simon Cauchemez Rapha?lle Métras Do Huu Dung Dirk Pfeiffer Azra C. Ghani 《PLoS computational biology》2010,6(2)
Outbreaks of H5N1 in poultry in Vietnam continue to threaten the livelihoods of those reliant on poultry production whilst simultaneously posing a severe public health risk given the high mortality associated with human infection. Authorities have invested significant resources in order to control these outbreaks. Of particular interest is the decision, following a second wave of outbreaks, to move from a “stamping out” approach to the implementation of a nationwide mass vaccination campaign. Outbreaks which occurred around this shift in policy provide a unique opportunity to evaluate the relative effectiveness of these approaches and to help other countries make informed judgements when developing control strategies. Here we use Bayesian Markov Chain Monte Carlo (MCMC) data augmentation techniques to derive the first quantitative estimates of the impact of the vaccination campaign on the spread of outbreaks of H5N1 in northern Vietnam. We find a substantial decrease in the transmissibility of infection between communes following vaccination. This was coupled with a significant increase in the time from infection to detection of the outbreak. Using a cladistic approach we estimated that, according to the posterior mean effect of pruning the reconstructed epidemic tree, two thirds of the outbreaks in 2007 could be attributed to this decrease in the rate of reporting. The net impact of these two effects was a less intense but longer-lasting wave and, whilst not sufficient to prevent the sustained spread of outbreaks, an overall reduction in the likelihood of the transmission of infection between communes. These findings highlight the need for more effectively targeted surveillance in order to help ensure that the effective coverage achieved by mass vaccination is converted into a reduction in the likelihood of outbreaks occurring which is sufficient to control the spread of H5N1 in Vietnam. 相似文献
914.
Safi Bagherpour Ahmet Kahraman Musa Doğan Ferhat Celep Birol Başer Sevil Pehlivan 《Central European Journal of Biology》2010,5(6):872-879
The gross anatomical features, namely stem, blade and petiole and the micromorphological features, trichome, pollen and nutlet
of Salvia vermifolia Hedge & Hub.-Mor. (Sect. Aethiopis Bentham, Lamiaceae) were examined using light microscopy (LM) and scanning electron microscopy (SEM). S. vermifolia is a perennial endemic herb growing on igneous and serpentine slopes in Sivas province, Central Anatolia, Turkey. The results
obtained from anatomical studies show that the stem is made up of 4–8-layers of collenchyma cells and 1-3-layers chlorenchyma
cells. The blade is amphistomatic, bifacial, with 2-3-layered palisade cells on the adaxial. The petiole has three large central
bundles and six small subsidiary bundles. Peltate glandular, capitate glandular and non-glandular trichomes are present in
S. vermifolia. The peltate glandular trichomes are present in abundance on the calyx and corolla, and capitate glandular trichomes are
predominant on the calyx, inflorescence axis, pedicel and stem. The acicular non-glandular trichomes are mainly situated on
the calyx, corolla, inflorescence axis and pedicels whereas the floccose non-glandular trichomes are common on both sides
of the leaf, inflorescence axis and petiole. The pollen grains are hexacolpate to octacolpate, medium to large (P, polar axis=45.29–62.49
μm; E, equatorial axis=45.32-62.38 μm), oblate-spheroidal to prolate-spheroidal (P/E=0.91–1.02) and their exine ornamentation
is bireticulate. The nutlets are 2.70–2.90 mm long and 1.90–2.13 mm wide, brown, ovoid-oblong in their outline, rounded-trigonous
in transverse section, and their surface is glabrous and colliculate. 相似文献
915.
Thuy Do Steven C. Gilbert Douglas Clark Farida Ali Clarissa C. Fatturi Parolo Marisa Maltz Roy R. Russell Peter Holbrook William G. Wade David Beighton 《PloS one》2010,5(2)
Streptococcus mutans, consisting of serotypes c, e, f and k, is an oral aciduric organism associated with the initiation and progression of dental caries. A total of 135 independent Streptococcus mutans strains from caries-free and caries-active subjects isolated from various geographical locations were examined in two versions of an MLST scheme consisting of either 6 housekeeping genes [accC (acetyl-CoA carboxylase biotin carboxylase subunit), gki (glucokinase), lepA (GTP-binding protein), recP (transketolase), sodA (superoxide dismutase), and tyrS (tyrosyl-tRNA synthetase)] or the housekeeping genes supplemented with 2 extracellular putative virulence genes [gtfB (glucosyltransferase B) and spaP (surface protein antigen I/II)] to increase sequence type diversity. The number of alleles found varied between 20 (lepA) and 37 (spaP). Overall, 121 sequence types (STs) were defined using the housekeeping genes alone and 122 with all genes. However π, nucleotide diversity per site, was low for all loci being in the range 0.019–0.007. The virulence genes exhibited the greatest nucleotide diversity and the recombination/mutation ratio was 0.67 [95% confidence interval 0.3–1.15] compared to 8.3 [95% confidence interval 5.0–14.5] for the 6 concatenated housekeeping genes alone. The ML trees generated for individual MLST loci were significantly incongruent and not significantly different from random trees. Analysis using ClonalFrame indicated that the majority of isolates were singletons and no evidence for a clonal structure or evidence to support serotype c strains as the ancestral S. mutans strain was apparent. There was also no evidence of a geographical distribution of individual isolates or that particular isolate clusters were associated with caries. The overall low sequence diversity suggests that S. mutans is a newly emerged species which has not accumulated large numbers of mutations but those that have occurred have been shuffled as a consequence of intra-species recombination generating genotypes which can be readily distinguished by sequence analysis. 相似文献
916.
Yanlan Yu Pierre Lee Yaohuang Ke Yongke Zhang Qiu Yu Jonathan Lee Mingzhen Li Jialiang Song Jungang Chen Jihong Dai Fernando Jose Rebelo Do Couto Zhiqiang An Weimin Zhu Guo-Liang Yu 《PloS one》2010,5(2)
Rabbit antibodies have been widely used in research and diagnostics due to their high antigen specificity and affinity. Though these properties are also highly desirable for therapeutic applications, rabbit antibodies have remained untapped for human disease therapy. To evaluate the therapeutic potential of rabbit monoclonal antibodies (RabMAbs), we generated a panel of neutralizing RabMAbs against human vascular endothelial growth factor-A (VEGF). These neutralizing RabMAbs are specific to VEGF and do not cross-react to other members of the VEGF protein family. Guided by sequence and lineage analysis of a panel of neutralizing RabMAbs, we humanized the lead candidate by substituting non-critical residues with human residues within both the frameworks and the CDR regions. We showed that the humanized RabMAb retained its parental biological properties and showed potent inhibition of the growth of H460 lung carcinoma and A673 rhabdomyosarcoma xenografts in mice. These studies provide proof of principle for the feasibility of developing humanized RabMAbs as therapeutics. 相似文献
917.
Background
Analysis of gingival crevicular fluid (GCF) samples may give information of unattached (planktonic) subgingival bacteria. Our study represents the first one targeting the identity of bacteria in GCF.Methodology/Principal Findings
We determined bacterial species diversity in GCF samples of a group of periodontitis patients and delineated contributing bacterial and host-associated factors. Subgingival paper point (PP) samples from the same sites were taken for comparison. After DNA extraction, 16S rRNA genes were PCR amplified and DNA-DNA hybridization was performed using a microarray for over 300 bacterial species or groups. Altogether 133 species from 41 genera and 8 phyla were detected with 9 to 62 and 18 to 64 species in GCF and PP samples, respectively, per patient. Projection to latent structures by means of partial least squares (PLS) was applied to the multivariate data analysis. PLS regression analysis showed that species of genera including Campylobacter, Selenomonas, Porphyromonas, Catonella, Tannerella, Dialister, Peptostreptococcus, Streptococcus and Eubacterium had significant positive correlations and the number of teeth with low-grade attachment loss a significant negative correlation to species diversity in GCF samples. OPLS/O2PLS discriminant analysis revealed significant positive correlations to GCF sample group membership for species of genera Campylobacter, Leptotrichia, Prevotella, Dialister, Tannerella, Haemophilus, Fusobacterium, Eubacterium, and Actinomyces.Conclusions/Significance
Among a variety of detected species those traditionally classified as Gram-negative anaerobes growing in mature subgingival biofilms were the main predictors for species diversity in GCF samples as well as responsible for distinguishing GCF samples from PP samples. GCF bacteria may provide new prospects for studying dynamic properties of subgingival biofilms. 相似文献918.
The prespore-specific activation of sigma factor SigF (σF) in Bacillus subtilis has been explained mainly by two factors, i.e., the transient genetic asymmetry and the volume difference between the mother cell and the prespore. Here, we systematically surveyed the effect of these two factors on sporulation using a quantitative modeling and simulation architecture named hybrid functional Petri net with extension (HFPNe). Considering the fact that the transient genetic asymmetry and the volume difference in sporulation of B. subtilis finally bring about the concentration difference in two proteins SpoIIAB (AB) and SpoIIAA (AA) between the mother cell and the prespore, we have surveyed the effect of AB and AA concentration on the prespore-specific activation of σF occurring in the early stage of sporulation. Our results show that the prespore-specific activation of σF could be governed by the ratio of AA to AB rather than their concentrations themselves. Our model also suggests that B. subtilis could maximize the ratio of AA to AB in the prespore and minimize it in the mother cell by employing both the transient genetic asymmetry and the volume difference simultaneously. This might give a good explanation to the co-occurrence of the transient asymmetry and the volume difference during sporulation of B. subtilis. In addition, we suggest for the first time that the σF activation in the prespore might be switched off by the decrease in the ratio of AA to AB after the transient genetic asymmetry is to an end by completion of DNA translocation into the prespore. 相似文献
919.
Joon-Chul Kim Min-Jeong Son Krishna P. Subedi Do Han Kim Sun-Hee Woo 《Molecules and cells》2010,29(4):387-395
HL-1 cells are the adult cardiac cell lines available that continuously divide while maintaining an atrial phenotype. Here
we examined the expression and localization of inositol 1,4,5-trisphosphate receptor (IP3R) subtypes, and investigated how pattern of IP3-induced subcellular local Ca2+ signaling is encoded by multiple IP3R subtypes in HL-1 cells. The type 1 IP3R (IP3R1) was expressed in the perinucleus with a diffuse pattern and the type 2 IP3R (IP3R2) was expressed in the cytosol with a punctate distribution. Extracellular ATP (1 mM) elicited transient intracellular Ca2+ releases accompanied by a Ca2+ oscillation, which was eliminated by the blocker of IP3Rs, 2-APB, and attenuated by ryanodine. Direct introduction of IP3 into the permeabilized cells induced Ca2+ transients with Ca2+ oscillations at ⩾ 20 μM of IP3, which was removed by the inhibition of IP3Rs using 2-APB and heparin. IP3-induced local Ca2+ transients contained two distinct time courses: a rapid oscillation and a monophasic Ca2+ transient. The magnitude of Ca2+ oscillation was significantly larger in the cytosol than in the nucleus, while the monophasic Ca2+ transient was more pronounced in the nucleus. These results provide evidence for the molecular and functional expression
of IP3R1 and IP3R2 in HL-1 cells, and suggest that such distinct local Ca2+ signaling may be correlated with the punctate distribution of IP3R2s in the cytosol and the diffuse localization of IP3R1 in the peri-nucleus. 相似文献
920.