Enhanced ethanol formation by Clostridium thermocellum via pyruvate decarboxylase.

BACKGROUND: Pyruvate decarboxylase (PDC) is a well-known pathway for ethanol production, but has not been demonstrated for high titer ethanol production at temperatures above 50 °C. RESULT: Here we examined the thermostability of eight PDCs. The purified bacterial enzymes retained 20% of activity after incubation for 30 min at 55 °C. Expression of these PDC genes, except the one from Zymomonas mobilis, improved ethanol production by Clostridium thermocellum. Ethanol production was further improved by expression of the heterologous alcohol dehydrogenase gene adhA from Thermoanaerobacterium saccharolyticum. CONCLUSION: The best PDC enzyme was from Acetobactor pasteurianus. A strain of C. thermocellum expressing the pdc gene from A. pasteurianus and the adhA gene from T. saccharolyticum was able to produce 21.3 g/L ethanol from 60 g/L cellulose, which is 70% of the theoretical maximum yield.

Evaluation of the antibacterial activity of a cationic polymer in aqueous solution with a convenient electrochemical method.

Quaternized chitosan is a cationic biopolymer with good antibacterial activity, biocompatibility, and biodegradability, and it has been widely applied in many fields. We have developed a convenient method to evaluate the antibacterial activity of hydroxypropyltrimethylammonium chloride chitosan (HACC) with a nonionic surfactant poloxamer in aqueous solution by monitoring the change of the oxidation peak current in cyclic voltammetry. Increasing values of the oxidation peak current were positively correlated with the antibacterial activity of HACC-poloxamer solutions. Optical microscope images, the zeta potential, and fluorescence spectroscopy showed that the aggregation state of HACC-poloxamer was related to the ratio of the two polymers and also to the antibacterial activity and oxidation peak current. At an HACC-to-poloxamer ratio of 1:0.75, the maximum surface charge density and the smooth edge of HACC-poloxamer aggregates can accelerate diffusion in aqueous solution. It is expected that this convenient method can be applied for a quick evaluation of the antibacterial activity of cationic biopolymers in aqueous solution. Graphical Abstract The cyclic voltammograms of MB in HACC/poloxamer solution, and the antibacterial efficiency against S. aureus after incubated with HACC (a) and 1/0.75 of HACC/poloxamer (b).

Persistent clinical symptoms and their association with CM syndromes in post-COVID-19 rehabilitation patients in Hong Kong.

Background: Heterogeneous clinical conditions were observed in individuals who had recovered from COVID-19 and some symptoms were found to persist for an extended period post-COVID. Given the non-specific nature of the symptoms, Chinese medicine (CM) is advantageous in providing holistic medical assessment for individuals experiencing persisting problems. Chinese medicine is a type of treatment that involves prescribing regimens based on CM Syndromes diagnosed by CM practitioners. However, inadequate research on CM elements behind the practice has faced scrutiny. Methods: This study analysed 1058 CM medical records from 150 post-COVID-19 individuals via a semi-text-mining approach. A logistic model with MCMCglmm was then utilised to analyse the associations between the indicated factors and identified conditions. Calculations were performed using R Studio and related libraries. Results: With the semi-text-mining approach, three common CM Syndromes (Qi and Yin Deficiency, Lung and Spleen Deficiency, Qi Deficiency of both Spleen and Lung) and nine clinical conditions (fatigue, poor sleep, dry mouth, shortness of breath, cough, headache, tiredness, sweating, coughing phlegm) were identified in the CM clinical records. Analysis via MCMCglmm revealed that the occurrence of persisting clinical conditions was significantly associated with female gender, existing chronic conditions (hypertension, high cholesterol, and diabetes mellitus), and the three persisting CM Syndromes. The current study triangulated the findings from our previous observational study, further showing that patients with certain post-COVID CM Syndromes had significantly increased log-odds of having persisting clinical conditions. Furthermore, this study elucidated that the presence of chronic conditions in the patients would also significantly increase the log-odds of having persistent post-COVID clinical conditions. Conclusion: This study provided insights on mining text-based CM clinical records to identify persistent post-COVID clinical conditions and the factors associated with their occurrence. Future studies could examine the integration of integrating exercise modules, such as health qigong Liuzijue, into multidisciplinary rehabilitation programmes.

Preparation of nanostructured PDMS film as flexible immunosensor for cortisol analysis in human sweat.

This work proposed a novel and flexible immunosensor for highly selective and sensitive determination of cortisol in sweat. The flexible electrode was developed by transferring multi-walled carbon nanotubes (MWCNTs) film on polydimethylsiloxane (PDMS) substrate and subsequent electrochemical deposition of Au nanoparticles (AuNPs) on the MWCNTs surface. The obtained AuNPs/MWCNTs/PDMS electrode was then covalently immobilized with anti-cortisol monoclonal antibody (Anti-Cmab) and blocked with BSA. Scanning electron microscope confirmed that MWCNTs have been firmly combined with PDMS and AuNPs distributed uniformly on the surface of MWCNTs. The PDMS-based sensor possesses a good mechanical stability against stretching, bending and twisting, displaying stable electrochemical performance under deformation. After optimizing the analytical parameters, the developed immunosensor allowed a facile quantification of cortisol in the range of 1 fg/mL-1 µg/mL with a detection limit of 0.3 fg/mL. The cortisol immunosensor was further used to evaluate cortisol levels in human sweat, and the results corresponded closely with commercially available chemiluminescence immunoassay (CLIA) method. Results indicated that the new cortisol immunosensor could provide an effective tool for the noninvasive, point of care measurement of sweat cortisol levels and is promise to be a wearable biosensor for the healthy monitoring.

Sensitive Electrochemical Capsaicin Sensor Based on a Screen Printed Electrode Modified with Poly(sodium 4-styrenesulfonate) Functionalized Graphite.

A sensitive capsaicin sensor was constructed based on a poly(sodium 4-styrenesulfonate) functionalized graphite modified screen printed electrode (PSS-Grp/SPE) in this study. The PSS-Grp and poly(diallyldimethylammonium chloride) functionalized graphite (PDDA-Grp) were easily synthesized by interacting Grp with PSS and PDDA through sonication, and resulted in negative and with positive charges on the surface, respectively. The prepared PSS-Grp and PDDA-Grp were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and ultraviolet and visible spectroscopy (UV-vis). The electrochemical performance of PSS-Grp in a 50 µM capsaicin solution presented a current density of 33 µA cm-2, which was much higher than the PDDA-Grp of 1.5 µA cm-2. Our study showed that capsaicin could interact better with strong negative charges on the PSS-Grp/SPE surface to give a higher electrochemical response. The direct electrochemical sensing of capsaicin was achieved at PSS-Grp/SPE using differential pulse stripping voltammetry (DPSV) under the optimized conditions.

Association between Polymorphisms in Interleukins 4 and 13 Genes and Chronic Periodontitis in a Han Chinese Population.

Chronic periodontitis (CP) is one of the most common chronic inflammatory diseases and cytokines play a pivotal role in the regulation of immune response. Interleukin-4 (IL-4) and interleukin-13 (IL-13) are anti-inflammatory cytokines and several polymorphisms of them have been proved involved in periodontal disease. This study aimed to evaluate whether three single nucleotide polymorphisms (SNPs), rs2070874 and rs2243248 from IL4 and rs1800925 from IL13, are associated with CP in a Han Chinese population consisting of 440 moderate or severe CP patients and 324 healthy controls. Genomic DNA extracted from buccal epithelial cells of the included participants were genotyped using a matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry method. No significant association between rs2070874 or rs1800925 and CP was found, while the frequencies of rs2243248 and two haplotypes C-G-T and C-T-T showed significant differences between the two groups. The results suggest that the polymorphism rs2243248 and haplotypes C-G-T and C-T-T may be associated with CP susceptibility in the present Han Chinese population.

Drug co-loading and pH-sensitive release core-shell nanoparticles via layer-by-layer assembly.

Multifunctional core-shell nanoparticles are widely used for biomedical and catalytic applications. In this work, bilayers of chitosan (Cs) and phosphorylated polyvinyl alcohol (PPVA) were sequentially deposited on 3-Aminopropyltri-ethoxysilane-modified SiO2 nanoparticles via layer-by-layer electrostatic self-assembly. The good spherical shape and size distribution were observed by DLS and transmission electron microscope analysis. 7-Hydroxycoumarin (7-HC) and rhodamine B (RhB) as model drugs were loaded in the core and shell of the nanoparticles separately. Confocal laser scanning microscopy shows the core-shell structure of HC-SiO2(PPVA/Cs)n-RhB nanoparticles and the embedded location of 7-HC and RhB. The pH-sensitive release investigation of RhB indicates that the release profiles of RhB from HC-SiO2(PPVA/Cs)3PPVA-RhB core-shell nanoparticles are totally different at pH values of 2.0, 7.4, and 9.2. These results predict that the multifunctional nanoparticle SiO2(PPVA/Cs)n has a great potential for drug delivery.

The association of CSF-1 gene polymorphism with chronic periodontitis in the Han Chinese population.

BACKGROUND: Chronic periodontitis (CP) is a multifactorial complex periodontal disease involving immune response, inflammation, alveolar bone resorption, and attachment loss. Colony stimulating factor-1 (CSF-1) controls the production, differentiation, and function of macrophages and plays a vital role in the innate immune response to the external microbial infections, suggesting the potential role of CSF-1 in the pathogenesis of periodontitis. The objective of this study is to determine the association of single nucleotide polymorphisms (SNPs) rs333967, rs2297706, and rs1058885 with CP in the Han Chinese population. METHODS: Genomic DNA was isolated from buccal epithelial cells obtained from unrelated Chinese participants (440 patients with CP and 324 controls). The SNPs were genotyped by a matrix-assisted laser desorption/ionization time-of-flight mass spectrometry method. RESULTS: Three previously identified SNPs were genotyped in Han Chinese with Shanghai origin, but none of them was statistically significantly associated with CP. However, a T-C-G haplotype in male participants showed an observed P value of 4.52(E-08), with an odds ratio of 0.092. CONCLUSION: None of the individual SNPs among rs333967, rs2297706, and rs1058885 in CSF-1 was found statistically significantly associated with CP in the Han Chinese population with Shanghai origin, whereas a haplotype T-C-G showed an observed statistically significant association with decreased risk of CP susceptibility in males.

[Correlation between single nucleotide polymorphism and periodontitis susceptibility in Shanghai Chinese patients].

PURPOSE: To investigate the correlation between 12 single nucleotide polymorphisms (SNPs) from 7 genes and periodontitis of susceptibility in Shanghai Chinese patients. METHODS: Genotypes of randomly grouped 50 health control subjects and 48 patients with chronic periodontitis were genotyped by MALDI-TOF MS detection system. A questionnaire, medical history, family history, signs, laboratory tests, treatment, follow-up information were collected. Statistical analysis of Chi-square test was performed using SPSS13.0 software package. RESULTS: In the screening of the 12 target SNPs,the GG genotype of rs2891168 correlated significantly with periodontitis, OR=3.071(95%CI:1.018-9.260,P=0.046). CONCLUSION: The GG genotype of rs2891168 may correlate significantly with periodontitis of Shanghai Chinese patients and further studies are needed to verify this finding. Supported by Natural Science Foundation of Shanghai Municipality (Grant No.10ZR1425900) and Research Fund of Bureau of Health of Shanghai Municipality (Grant No.2009202).