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991.
Increased Insect Virulence in Beauveria bassiana Strains Overexpressing an Engineered Chitinase
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Yanhua Fan Weiguo Fang Shujuan Guo Xiaoqiong Pei Yongjun Zhang Yuehua Xiao Demou Li Kai Jin Michael J. Bidochka Yan Pei 《Applied microbiology》2007,73(1):295-302
Entomopathogenic fungi are currently being used for the control of several insect pests as alternatives or supplements to chemical insecticides. Improvements in virulence and speed of kill can be achieved by understanding the mechanisms of fungal pathogenesis and genetically modifying targeted genes, thus improving the commercial efficacy of these biocontrol agents. Entomopathogenic fungi, such as Beauveria bassiana, penetrate the insect cuticle utilizing a plethora of hydrolytic enzymes, including chitinases, which are important virulence factors. Two chitinases (Bbchit1 and Bbchit2) have previously been characterized in B. bassiana, neither of which possesses chitin-binding domains. Here we report the construction and characterization of several B. bassiana hybrid chitinases where the chitinase Bbchit1 was fused to chitin-binding domains derived from plant, bacterial, or insect sources. A hybrid chitinase containing the chitin-binding domain (BmChBD) from the silkworm Bombyx mori chitinase fused to Bbchit1 showed the greatest ability to bind to chitin compared to other hybrid chitinases. This hybrid chitinase gene (Bbchit1-BmChBD) was then placed under the control of a fungal constitutive promoter (gpd-Bbchit1-BmChBD) and transformed into B. bassiana. Insect bioassays showed a 23% reduction in time to death in the transformant compared to the wild-type fungus. This transformant also showed greater virulence than another construct (gpd-Bbchit1) with the same constitutive promoter but lacking the chitin-binding domain. We utilized a strategy where genetic components of the host insect can be incorporated into the fungal pathogen in order to increase host cuticle penetration ability. 相似文献
992.
The interaction between surfactant and fluorescein was studied, using a fluorescence spectroscopy and flow-injection (FI) chemiluminescence (CL) method. It was found that the cationic surfactant cetyltrimethylammonium bromide (CTAB) could cause the structural transformation of fluorescein from the quinone to the spirolactone form, and greatly enhance the CL intensity of the fluorescein-human serum albumin (HSA) complex. Based on this finding, a rapid and sensitive FI-CL method was developed for the determination of HSA. Under the optimum conditions, the proposed method has a linear range of 0.05-24.0 microg/mL, with a detection limit of 0.03 microg/mL for HSA (3sigma). The relative standard deviation (RSD) of 1.2 microg/mL HSA (n = 8) is 0.8%. The method was applied to the determination of protein content in urine samples, with satisfactory results. Density functional theory was used to study the mechanism of surfactant-enhanced CL intensity of the fluorescein-HSA complex. 相似文献
993.
Kai K. Eberle K. E. Zinsmaier Sigrid Buchner M. Gruhn Mario Jenni Christine Arnold Christian Leibold Dietmar Reisch N. Walter Ernst Hafen A. Hofbauer Gert O. Pflugfelder E. Buchner 《Cell and tissue research》1998,294(2):203-217
The “cysteine string protein” (CSP) genes of higher eukaryotes code for a novel family of proteins characterized by a “J” domain and an unusual cysteine-rich region. Previous studies had localized the proteins in neuropil and synaptic terminals of larval and adult Drosophila and linked the temperature-sensitive paralysis of the mutants described here to conditional failure of synaptic transmission. We now use the null mutants as negative controls in order to reliably detect even low concentrations of CSPs by immunohistochemistry, employing three monoclonal antibodies. In wild-type flies high levels of cysteine string proteins are found not only in apparently all synaptic terminals of the embryonic, larval, and adult nervous systems, but also in the “tall cells” of the cardia, in the follicle cells of the ovary, in specific structures of the female spermatheca, and in the male testis and ejaculatory bulb. In addition, low levels of CSPs appear to be present in all tissues examined, including neuronal perikarya, axons, muscles, Malpighian tubules, and salivary glands. Western blots of isolated tissues demonstrate that of the four isoforms expressed in heads only the largest is found in non-neural organs. The wide expression of CSPs suggests that at least some of the various phenotypes of the null mutants observed at permissive temperatures, such as delayed development, short adult lifespan, modified electroretinogram, and optomotor behavior, may be caused by the lack of CSPs outside synaptic terminals. 相似文献
994.
1. The sedimentation constant of hog thyroglobulin is 19.2ċ10–13. That of human thyroglobulin is essentially the same. 2. The specific volume of hog thyroglobulin is 0.72. 3. The isoelectric point of native hog thyroglobulin is at pH 4.58, that of denatured thyroglobulin at pH 5.0. 4. The molecular weight of hog thyroglobulin is, in round numbers, 700,000, as calculated from the sedimentation and diffusion constants, or 650,000, as calculated from the sedimentation equilibrium data. 5. The thyroglobulin molecule deviates markedly from the spherical. 相似文献
995.
Pan Zhang Jingwei Feng Yunjun Liao Junrong Cai Tao Zhou Mingliang Sun Jianhua Gao Kai Gao 《Biochemical and biophysical research communications》2018,495(3):2249-2256
Background
Flap necrosis due to insufficient blood supply is a common postoperative complication in random pattern flaps. Stem cell therapies have emerged as promising biologics for tissue ischemia. A novel fat derived product, stromal vascular fraction gel (SVF-gel), can be prepared with lipoaspirate through simple mechanical processing, removing only the lipid content. SVF-gel enriches adipose-derived stem cells and potentially beneficial for flap necrosis.Methods
Nude mice ischemic flaps were treated with human SVF-gel, stromal vascular fraction (SVF) cell suspension or saline (n = 10). They were injected to the flap recipient beds, and necrosis and vascularization was assessed on postoperative day 14. We harvested the necrosis-free distal to evaluated skin healthiness and neovasculogenesis by Masson's trichrome stain and immunofluorescence, etc. Pro-angiogenic factors were assessed with tissue qRT-PCR. Finally, we traced the grafted human tissue with immunofluorescence.Results
SVF-gel-treated flaps have the smallest necrotic zones (22.05% ± 0.0438) compared with the saline controls (53.78% ± 0.1412) or SVF-treated ones (35.54% ± 0.0850, p = 0.039). Numerous functional musculocutaneous perforators were developed around SVF-gel grafts. The SVF-gel-treated skin had the best fat restoration (231.3 ± 48.1 μm) among three groups (F = 10.83, p = 0.0102) while saline-treated flap distal appeared fibrotic. SVF-gel-treated flaps also had ~43% more CD31 + capillaries (p = 0.0152) with ~3 folds more gene expression of angiogenic cytokines of VEGF and bFGF (p = 0.0310 and 0.0303, respectively) than saline-treated controls. Furthermore, we found hSVF-gel cells (hGolgi+) had directly engrafted as vessel component (α-smooth muscle actin, α-SMA+) to the flap.Conclusion
Adipose cellular matrix enhanced flap neovascularization partly by direct incorporation, improved flap survival and fat restoration. The composition-selective fat grafting with SVF-gel demonstrated efficacy comparable with stem cell therapy and is especially valuable for clinical translation. 相似文献996.
997.
998.
Jing Chen‐Roetling Sheng‐Kai Ma Yang Cao Aishwarya Shah Raymond F. Regan 《Journal of neurochemistry》2018,145(6):464-473
999.
Spatial and temporal patterns of nest distribution influence sexual selection in a marine fish
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In many species, the natural distribution of material resources important for reproduction can profoundly impact reproductive success among individuals and, hence, the opportunity and intensity of sexual selection. Here, we report on a field‐based experiment investigating the effects of nest aggregation on sexual selection in a fish, the sand goby Pomatoschistus minutus. We found that the distribution of potential nests (sparse versus aggregated nest treatments) affected patterns of nest colonization and reproductive success. Specifically, in the treatment with aggregated nesting resources, a greater proportion of nests remained unoccupied by sand goby males. Although the size of nesting males did not differ between treatments, eggs accumulated more rapidly when nests were sparsely distributed. We found that the opportunity for selection decreased over time with the accumulation of eggs in the nests in both the aggregated and sparse treatments. Moreover, the effect of male size on reproductive success was influenced by an interaction between nest distribution and time, with the selection gradient being highest right after nest colonization when nests were aggregated, while the opposite pattern was observed in the sparse nest treatment. Such findings highlight the vital role that environmental and social factors can play in determining the importance of male phenotypic traits (in this case, male size). More broadly, our results also underscore how the natural distribution of resources, both in space and time, can impact the strength of sexual selection acting on wild animal populations. 相似文献
1000.