Single nanosheet can sustainably generate oxygen and inhibit respiration simultaneously in cancer cells.

In a tumor, the abnormal cancer cell proliferation results in an insufficient O2 supply, and meanwhile cancer cells consume O2 very fast. The imbalance between a low oxygen supply and overwhelming oxygen consumption results in a low oxygen concentration in solid tumors. Therefore, in order to relieve hypoxia in tumors, it is necessary to not only sustainably generate O2, but also inhibit mitochondrial respiration simultaneously. Here, we found that a single Ti2C(OH)2 nanomaterial not only can sustainably generate O2 but also simultaneously highly inhibits mitochondrial respiration via binding phosphorylation proteins onto the surface in cancer cells. Ce6 was linked onto Ti2C(OH)2, forming Ti2C(OH)2-Ce6. Ti2C(OH)2-Ce6 could highly relieve hypoxia in tumors via the combination of sustainable O2 generation and respiration inhibition, produce enough 1O2 to kill cancer cells via PDT, and also effectively convert the absorbed light energy into thermal energy to kill cancer cell via PTT, thereby highly enhancing the cancer therapy.

Correction: Single nanosheet can sustainably generate oxygen and inhibit respiration simultaneously in cancer cells.

Correction for 'Single nanosheet can sustainably generate oxygen and inhibit respiration simultaneously in cancer cells' by Wei-Qiang Huang et al., Mater. Horiz., 2021, DOI: .

Facile Multicomponent Polymerization and Postpolymerization Modification via an Effective Meldrum's Acid-Based Three-Component Reaction.

Providing access to highly diverse polymer structures by multicomponent reactions is highly desirable; efficient Meldrum's acid-based multicomponent reactions, however, have been rarely highlighted in polymer chemistry. Here, the three-component reaction of Meldrum's acid, indole, and aldehyde is introduced into polymer synthesis. Direct multicomponent polymerization of Meldrum's acid, dialdehyde, and diindole can perform under mild conditions, resulting in complex Meldrum's acid-containing polymers with well-defined structures, and high molecular weights. Additionally, nearly quantitative postpolymerization modification can also perform via this Meldrum's acid-based multicomponent reaction. These results indicate that Meldrum's acid-based multicomponent reaction will be a potential tool to prepare novel polymers.

Interactions in DNA Condensation: An Important Factor for Improving the Efficacy of Gene Transfection.

The rapid developments of gene therapy are benefit from the construction of efficient gene vectors, which help therapy genes efficiently overcome the barriers in the transport and transfection. Condensing DNA into nanoparticles is a crucial role in gene transfection, and the electrostatic interactions of synthetic cationic liposomes and cationic polymers with DNA are generally used for condensing DNA. Recent research has shown that the introduction of the hydrophobic interaction, hydrogen bonding, and coordinative interactions to the gene delivery vectors is also very important for DNA condensation, delivery, and transfection. This review focuses on the four types of interactions in condensed DNA nanoparticles, which could provide a new perspective for improving gene transfection efficacy.

[shRNAs driven by K14 promoter induce tissue-specific RNA interference].

RNA interference is an efficient method for exploring gene function. Accumulating evidence suggests that RNA Pol II promoters can direct cell- or tissue-specific gene silencing. A eGFP-shRNA fusion construct transcribed from an RNA Pol II promoter (K14 promoter) was used to induce gene-specific shRNA silencing ofBMP4 gene expression. Recombinant vectors (pEGFP-C1-shRNA, psiCHECK-BMP4, and pEGFP-K14-shRNA) were constructed. Vectors pEGFP-C1-shRNA and psiCHECK-BMP4 were cotransfected into Hela cells (in vitro) and shRNA-induced inhibition efficiency was tested by a luciferase assay. The results showed that all the six interference sequences inhibited the expression of BMP4 with high efficiency (>60%), and the interference sequence 5# showed the highest efficiency. For in vivo screening of JB6-C41 cells transfected with vector pEGFP-K14-shRNA, the inhibition efficiency was assayed by quantitative RT-PCR and Western blotting analyses. The results showed that the mRNA and protein products of the exogenous BMP4 gene were efficiently and specifically inhibited. The efficiency of gene silencing was greater than 60%, except for sequence 3#. The declines in mRNA and protein expression levels were significantly correlated during gene silence by the shRNA. This system may be adapted for in vivo shRNA expression and gene silencing. This method may provide a novel approach for the application of RNAi technology in suppressing gene expression in the analysis of the mechanisms of hair follicle development in sheep.

[Effects of Sargassum confusum polysaccharide on the expression of p53 and Rb genes in mouse sarcoma S180 cells].

OBJECTIVE: To investigate effects of Sargassum confusum polysaccharide (SP) on the expressions of p53 and Rb genes. METHODS: The mice bearing S180 sarcoma were treated with abdominal SP injection at the daily dose of 50, 100 or 200 mg/kg for 10 consecutive days, The mice injected with 0.85% saline served as the negative control group and those with 5-fluorouracil (5-FU) injection as the positive control group. The tumor weight was measured to calculate the tumor inhibition rate. RT-PCR and Western blotting were used to detect the expression levels of p53 and Rb genes at the mRNA and protein levels, respectively. RESULTS: The 10-day SP treatment at 50, 100 and 200 mg/kg resulted in tumor growth inhibition rates of 30.5%, 47.6% and 63.5%, respectively. SP treatment upregulated the mRNA expressions and increased the protein levels of p53 and Rb in the tumors. CONCLUSION: SP has inhibitory effect against S180 sarcoma in vivo and can increase the expression levels of p53 and Rb genes at both the mRNA and protein levels.

[Separation, purification and spectrum analysis of SHP].

Crude SHP was obtained from extracting with hot water and precipitating with ethyl alcohol. Free proteins were removed by trypsinase combined with Sevage method. Different fractions were got by gel filtration chromatography. The molecule structure was analyzed by ultraviolet spectrum scanning and KBr infrared spectroscope. The results showed that the reaction of phenol-sulfuric acid was postiive, reaction of ninhydrin was weak positive and reaction of iodine-potassium iodide was negative, the extraction was regarded as a non-starch polysaccharide. Extraction rate of SHP was 8.56% and the content of polysaccharides was 90.96%. Gel filtration chromatography showed that SHP composed of furanopolysaccharides, xylose, galactose, arabinose, glucose, rhamnose and fructose. Ultraviolet spectrum showed that SHP contained little DNA and protein, infrared spectrum showed that SHP was main furanopolysaccharides and had beta-glycosidic bouds in its molecule structure, and there was a characteristic absorb peak of at-D-galactopyranosyl in it.

[Extraction and analysis of gracilaria gigas Harvey polysaccharides].

Gracilaria Gigas Harvey Polysaccharides (GHPS) were extracted with hot water and sedimentated with ethanol. The amount of polysaccharides was determined by phenol-H2SO4 method. The mineral elements and molecular configuration were analysed by inductively coupled plasma (ICP) and infrared absorption spectrum (IR). The rate of distillation was 14.98%, the amount of polysaccharides was 78.2%, and GHPS contained manifold mineral elements (Ca, Fe, Mg and S). The IR spectra manifested that the extraction was a compound of polysaccharides, i.e. acidic polysaccharides.

[Therapeutic effect of Seaweed Polysaccharide from Sargassum confusum on sarcoma s180 in mice and its mechanism].

BACKGROUND & OBJECTIVE: Previous chemotherapeutic drugs have side effects which restrict their application in treating tumors. This research was to explore the inhibitory effect of wild Seaweed Polysaccharide from Sargassum confusum (SP) on sarcoma S180 xenograft in mice and its mechanism to offer experimental basis for searching for antitumor drugs with high efficiency and low toxicity. METHODS: SP were prepared and injected abdominally in mice at the doses of 50, 100, and 200 mg/kg, respectively, for 10 days before tumor cell transplantation. The mice with injection of 0.85% normal saline were set as negative control. The weight of S180 xenografts in mice was measured to calculate the inhibitory rate of SP on S180 tumor; the cell cycle of thymocytes and splenocytes were measured by flow cytometry (FCM); DNA and protein syntheses in thymocytes and splenocytes were measured by incorporation of (3)H-TdR; the immunopotentiative effect of SP on mice was assessed by splenic lymphocytes transformation assay. RESULTS: The inhibitory rates of S180 xenografts in mice treated with 50, 100, and 200 mg/kg SP were 28.7%, 32.9%, and 50.3%, respectively. The thymocytes and splenocytes functions were significantly enhanced in SP groups than in control group (P<0.05, P<0.01). CONCLUSIONS: SP might inhibit the growth of S180 xenograft in mice through improving the functions of thymocytes and splenocytes.

[In vivo anti-tumor effect of polysaccharide from Sargassum confusum and the mechanisms].

OBJECTIVE: To study the anti-tumor effects of polysaccharide from Sargassum confusum in mice and explore the possible mechanisms. Methods Forty-five mice bearing transplanted tumor S180 were used to study the effects of polysaccharide on the tumor weight, thymus gland and spleen. The changes in serum contents of SOD, glutathione peroxidase (GSH-PX) activity and malondialdehyde (MDA) content were assayed. RESULTS: The polysaccharide from Sargassum confusum significantly inhibited the growth of S180 tumor in mice and enhanced the functions of the immune organs. SOD content and GSH-PX activity were significantly increased from 350.76+/-31.34 NU/ml, 299.36+/-43.63 U to 487.76+/-16.67 NU/ml,370.90+/-16.49 U(P<0.01), MDA content decreased from 9.46+/-1.77 nmol/ml to 7.26+/-1.18 nmol/ml in the serum after polysaccharide treatment. CONCLUSION: The anti-tumor effect of the polysaccharide from Sargassum confusum can be attributed to improve functions of the immune organs and enhance anti-oxidative capacity in tumor-bearing mice.

[Extraction and analysis of sargassum hemiphyllum polysaccharides].

Sargassum hemiphyllum polysaccharides (SHP) was extracted by thermal water method and the physical and chemical characters, the extraction rate, contents, compositions of SHP was studied. The result showed that SHP was ashen powder, water-soluble, insoluble in organic solvents. The reaction of iodide-potassium iodide was negative to evaluate that SHP was nonstarch polysaccharides. Extraction rate was 7.04% and the content of polysaccharides was 82.9%. Ultraviolet spectrum showed that there were little DNA and protein. Infrared spectroscopy showed that SHP was main pyrano polysaccharides and had beta-linked glycopolysaccharides in molecule structure of SHP. Thin layer chromatography traced that SHP could be xylan. The results indicated that the extract was not only polysaccharides but also higher purity and the method was high efficiency.

[FTIR study on the hypertrophicscar and normal skin tissues].

40 cases of hypertrophicscar (HS) tissues and corresponding normal skin tissues were studied by FTIR technique, and the results showed that all of the HS and normal tissues can be classified into three kinds. Furthermore, the absorption bands of biomacromolecule in collagen, protein, nucleic acid and lipid of hypertrophicscar are stronger than those of normal tissues. But there is no significant difference in A1,063/A1,548 between HS and normal tissues. It is suggested that the cells of HS could still be normally growing and should not be scathed in the treatment process.