Polyethylenimine-based nanovector grafted with mannitol moieties to achieve effective gene delivery and transfection.

Polyethylenimine (PEI), a kind of cationic non-viral gene delivery vector, is capable of stable and efficient transgene expression for gene delivery. However, low transfection efficiency in vivo along with high toxicity limited the further application of gene therapy in the clinic. To enhance gene transfection performance and reduce cytotoxicity of polyethylenimine, branched polyethylenimine-derived cationic polymers BPEI25 k-man-S/L/M/H with different grafting degree with mannitol moieties were prepared and the transfection efficiency was evaluated. Among them, BPEI25 k-man-L showed the best transfection efficiency, lower toxicity, and significantly enhanced long-term systemic transgene expression for 96 h in vivo even at a single-dose administration. The results of cellular uptake mechanism and western-blot experiments revealed that the mannitol modification of BPEI25 k induced and up-regulated the phosphorylation of caveolin-1 and thus enhanced the caveolae-mediated cellular uptake. This class of gene delivery system highlights a paradigmatic approach for the development of novel and safe non-viral vectors for gene therapy.

Enhance transgene responses through improving cellular uptake and intracellular trafficking by bio-inspired non-viral vectors.

BACKGROUND: Gene therapy remains a significant challenge due to lots of barriers limiting the genetic manipulation technologies. As for non-viral delivery vectors, they often suffer insufficient performance due to inadequate cellular uptake and gene degradation in endosome or lysosome. The importance of overcoming these conserved intracellular barriers is increasing as the delivery of genetic cargo. RESULTS: A surface-functionalized non-viral vector involving the biomimetic mannitol moiety is initiated, which can control the cellular uptake and promote the caveolae-mediated pathway and intracellular trafficking, thus avoiding acidic and enzymatic lysosomal degradation of loaded gene internalized by clathrin-mediated pathway. Different degrees of mannitol moiety are anchored onto the surface of the nanoparticles to form bio-inspired non-viral vectors and CaP-MA-40 exhibits remarkably high stability, negligible toxicity, and significantly enhanced transgene expression both in vitro and in vivo. CONCLUSIONS: This strategy highlights a paradigmatic approach to construct vectors that need precise intracellular delivery for innovative applications.

Effects of simulated flue gas on components of Scenedesmus raciborskii WZKMT.

Scenedesmus raciborskii WZKMT cultured with simulated flue gas was investigated. Cellular components, including total sugar, starch, chlorophyll, protein and lipid, were compared between simulated flue gas and 7% (v/v) CO2. Dissolution of SO2 and NO in simulated flue gas led to pH decrease and toxicity to microalgae cells. Furthermore, the death or aging of microalgae cells reduced the buffer capacity and caused decrease of simulated flue gas absorption. With 7% CO2, the highest total sugar and starch content could attain to 66.76% and 53.16%, respectively, which indicated S. raciborskii WZKMT is a desired feedstock candidate for bioethanol production. Microalgae growth and starch accumulation was inhibited, while cells produced more chlorophyll, protein and lipid when simulated flue gas was the carbon source. Fatty acids composition analysis indicated that there was no significant distinction on fatty acids relative content (fatty acid/TFA) between cells aerated using simulated flue gas and 7% CO2.

Artificial intelligence techniques to optimize the EDC/NHS-mediated immobilization of cellulase on Eudragit L-100.

Two artificial intelligence techniques, namely artificial neural network (ANN) and genetic algorithm (GA) were combined to be used as a tool for optimizing the covalent immobilization of cellulase on a smart polymer, Eudragit L-100. 1-Ethyl-3-(3-dimethyllaminopropyl) carbodiimide (EDC) concentration, N-hydroxysuccinimide (NHS) concentration and coupling time were taken as independent variables, and immobilization efficiency was taken as the response. The data of the central composite design were used to train ANN by back-propagation algorithm, and the result showed that the trained ANN fitted the data accurately (correlation coefficient R(2) = 0.99). Then a maximum immobilization efficiency of 88.76% was searched by genetic algorithm at a EDC concentration of 0.44%, NHS concentration of 0.37% and a coupling time of 2.22 h, where the experimental value was 87.97 ± 6.45%. The application of ANN based optimization by GA is quite successful.

A fractal-like kinetic equation to investigate temperature effect on cellulose hydrolysis by free and immobilized cellulase.

According to fractal-like theory in the heterogeneous system, a cellulase-catalyzed kinetic equation that contained two parameters (rate constant k and fractal dimension h) was deduced. The equation described directly the mathematical relationship between reducing sugar concentration and hydrolytic time, and accurately fitted the experimental data of free/immobilized cellulase at 37, 40, 44, 47, and 50 °C (R(2)>0.99). The fitted h value is estimated as a constant (0.6148) in these tested temperatures. The fitted k value increased with temperature increase, and the relationship agreed with Arrhenius equation (R(2)>0.98). The fractal-like equation could predict accurately the experimental data at low temperature 34 °C for free/immobilized cellulase and high temperature 53 °C for immobilized cellulase, but the prediction at 53 °C for free cellulase was not accurate enough due to its lower stability than immobilized cellulase. The application of fractal-like theory in cellulase kinetics is successful.

Impact of body mass index on blood pressures in a college student population / 南方医科大学学报

<p><b>OBJECTIVE</b>To explore the morbidity of hypertension and prehypertension and analyze the association between body mass index (BMI) and blood pressure in Chinese college students.</p><p><b>METHODS</b>This epidemiological study involved 490 Chinese college students (aged 15-25 years, mean 18.9∓1.2 years), and their body height, body weight, blood pressure and heart rate were recorded. The BMI was divided into four groups according to Chinese population standard classification.</p><p><b>RESULTS</b>Most students were southern Han Chinese. The incidences of overweight plus obesity and obesity were 12.9% and 4.1%, respectively. The morbidity of hypertension was 0.8% in this student population. The incidences of hypertension and pre-hypertension were higher in high BMI groups than those in low BMI groups. The systolic blood pressures were significantly higher in over-weight and obese groups than in the normal BMI and lean groups. BMI was positively correlated to systolic and diastolic blood pressures in this population.</p><p><b>CONCLUSION</b>High BMI is a predictor of elevated blood pressure in adolescent students.</p>

Cellulase deactivation based kinetic modeling of enzymatic hydrolysis of steam-exploded wheat straw.

Applying mass action law and quasi-steady-state theory, two cellulase kinetic models namely Eqs. (5) and (8) were developed on the basis of the first and second order reactions of enzyme deactivation, respectively. The two models are compared according to analysis of experimental data from enzymatic hydrolysis steam-exploded wheat straw. Both simulation and prediction results show Eq. (8) has much higher accuracy than Eq. (5). Analysis of initial hydrolysis rate is also in accordance with Eq. (8) and against Eq. (5). Fitted values of k(2) (the rate constant of product formation), k(de2) (the rate constant of enzyme deactivation) and K(e) (the equilibrium constant) determined from Eq. (8) are 0.4732 h(-1), 0.4011 L/(hg), and 16.8597 g/L, respectively. The higher the enzyme concentration is, the larger the deactivation rate.

Rhodococcus qingshengii sp. nov., a carbendazim-degrading bacterium.

A Gram-positive, aerobic, non-motile, mesophilic strain, djl-6(T), able to degrade carbendazim, was isolated from a carbendazim-contaminated soil sample from Jiangsu province, China. The taxonomic position of this isolate was analysed by using a polyphasic approach. Chemotaxonomic analysis including peptidoglycan type, diagnostic sugar composition, fatty acid profile, menaquinones, polar lipids and mycolic acids showed that the characteristics of strain djl-6(T) were in good agreement with those of the genus Rhodococcus. DNA-DNA hybridization showed that it had low genomic relatedness with Rhodococcus baikonurensis DSM 44587(T) (31.8 %), Rhodococcus erythropolis DSM 43066(T) (23.8 %) and Rhodococcus globerulus DSM 43954(T) (17.7 %), the three type strains to which strain djl-6(T) was most closely related based on 16S rRNA gene sequence analysis (99.78, 99.25 and 98.91 % similarity, respectively). Based on the phenotypic properties and DNA-DNA hybridization data, strain djl-6(T) (=CGMCC 1.6580(T) =KCTC 19205(T)) is proposed as the type strain of a novel Rhodococcus species, Rhodococcus qingshengii sp. nov.