Objective To analyze the mechanism of imipenem resistance in Pseudomonas aeruginosa clinical isolates. Methods? Antibiotic?resistance?was?analyzed?using?VITEK32?system.?Metallo?β-lactamase?activity?was?determined?by?double-disc?synergy?test.?Amp?C?β-lactamase?activity?was?determined?by?Kirby-Bauer?disc?method.?OprD?protein?was?analyzed?by?sodium?dodecyl sulphate-polyacrylamide gel electrophoresis. PCR was performed to amplify gene oprD. The amplified products were subject?to?sequencing?analysis.?The?phylogenetic?relationship?was?determined?using?random?amplified?polymorphic?DNA?(RAPD)?method. Results Membrane protein OprD was analyzed in 7 clinical isolates of imipenem-intermediate P. aeruginosa. Two strains were devoid of OprD proteins and the corresponding oprD genes were found disrupted by the insertion element ISRP10 in the coding regions. Five strains had OprD proteins with different sizes. Sequence analysis showed that the peptides ranged from 427 to 443 amino acids. Multiple amino acid substitutions and / or deletions were found within the Loop 1 through Loop 8 of the OprD secondary structures. Conclusions ISRP10 inactivation and amino acid substitutions in oprD gene confer imipenem resistance in the clinical isolates of P. aeruginosa.

Cephalosporins are widely used antibiotics owing to their broad activity spectra and low toxicity. Many of these medically important compounds are made chemically from 7-aminodeacetoxycephalosporanic acid. At present, this intermediate is made by synthetic ring-expansion of the inexpensive penicillin G to form G-7-ADCA, followed by enzymatic removal of the side chain to obtain 7-ADCA. The chemical synthetic process is expensive, complicated and environmentally unfriendly. Environmentally compatible enzymatic process is favorable compared with chemical synthesis. In our previous research, metabolic engineered Escherichia coli strain (H7/PG15) was constructed and used as whole-cell biocatalyst for the production of G-7-ADC with penicillin G as substrate. The whole-cell biocatalysis was studied by single factor experiment, including the composition of substrates and the conversion conditions (OD600, pH, concentration of penicillin G, MOPS, glucose, time and FeSO4). After optimization, 15 mmol/L of G-7-ADCA was obtained. The process is convenient, efficient and economic. This work would facilitate the industrial manufacturing and further product research.
Anti-Bacterial Agents ; biosynthesis ; Biocatalysis ; Cephalosporins ; biosynthesis ; Escherichia coli ; metabolism ; Metabolic Engineering

Isoprene is an important precursor of synthetic rubber material. In our previous study, metabolic engineered Escherichia coli strain (BW-01) was constructed and used to produce isoprene. Based on the theory of protein budget, using synthetic biology strategies including the increased copy number of genes and rare codons, we regulated the expression of key enzyme to improve isoprene production in Escherichia coli strain. Under shake-flask conditions, isoprene productivity of the engineered strain (BW-07) increased by 73% compared with BW-01, reached 761.1 mg/L. It provides a reference for further studies.
Butadienes ; Escherichia coli ; genetics ; metabolism ; Gene Dosage ; Hemiterpenes ; biosynthesis ; Industrial Microbiology ; Metabolic Engineering ; Mevalonic Acid ; Pentanes ; Synthetic Biology

To study the effects of surfactants on wettability of excipients, the contact angles of six types of surfactants on the surface of two common excipients and mixture of three surfactants with excipients were measured using hypsometry method. The results demonstrated that contact angle of water on the surface of excipients was associated with hydrophilcity of excipients. Contact angle was lowered with increase in hydrophilic groups of excipient molecules. The sequence of contact angle from small to large was starch < sodium benzoate < polyvinylpyrrolidone < sodium carboxymethylcellulose < sodium alginate < chitosan < hydroxypropyl methyl cellulose

The difficulty of wound healing in patients is a difficult problem that doctors in all clinical departments may encounter, and there is still no good solution. Resveratrol is a kind of natural active substance, which has anti-inflammatory, antioxidant, antibacterial, and angiogenesis promoting effects, and is a potential drug to promote wound healing. However, the clinical application of resveratrol is limited due to its low bioavailability. In this review, the molecular mechanism of resveratrol in promoting wound healing and its administration methods in wound treatment were reviewed to provide ideas for the redevelopment of resveratrol.

Acute hepatic porphyria （AHP） is a rare disease with abnormal heme metabolism， and breakthroughs have been made in the treatment of this disease in recent years. In addition to conventional treatment methods， this article reviews new therapies for AHP that are in the stage of initial clinical application or are still in the research stage， including RNAi therapy， enzyme replacement therapy， genetic supplementation of DNA or mRNA， drug molecular chaperones， and glycine transporter inhibitors for reducing heme synthesis. Moreover， this article also reviews the treatment of AHP-related comorbidities and complications， such as hyponatremia and posterior reversible encephalopathy syndrome. High glucose infusion is the main treatment method for AHP in China， and the improvement in diagnosis and increased attention to rare diseases in China has promoted the development of the diagnosis and treatment of AHP， and it is expected to explore more suitable treatment methods for AHP in the Chinese population in the future.

Mental fatigue is the subjective state of people after excessive consumption of information resources. Its impact on cognitive activities is mainly manifested as decreased alertness, poor memory and inattention, which is highly related to the performance after impaired working memory. In this paper, the partial directional coherence method was used to calculate the coherence coefficient of scalp electroencephalogram (EEG) of each electrode. The analysis of brain network and its attribute parameters was used to explore the changes of information resource allocation of working memory under mental fatigue. Mental fatigue was quickly induced by the experimental paradigm of adaptive N-back working memory. Twenty-five healthy college students were randomly recruited as subjects, including 14 males and 11 females, aged from 20 to 27 years old, all right-handed. The behavioral data and resting scalp EEG data were collected simultaneously. The results showed that the main information transmission pathway of the brain changed under mental fatigue, mainly in the frontal lobe and parietal lobe. The significant changes in brain network parameters indicated that the information transmission path of the brain decreased and the efficiency of information transmission decreased significantly. In the causal flow of each electrode and the information flow of each brain region, the inflow of information resources in the frontal lobe decreased under mental fatigue. Although the parietal lobe region and occipital lobe region became the main functional connection areas in the fatigue state, the inflow of information resources in these two regions was still reduced as a whole. These results indicated that mental fatigue affected the information resources allocation of working memory, especially in the frontal and parietal regions which were closely related to working memory.
Adult ; Aged ; Brain ; Female ; Frontal Lobe ; Humans ; Male ; Memory, Short-Term ; Mental Fatigue ; Resource Allocation ; Young Adult

The widespread application of next generation sequencing (NGS) in clinical settings has enabled testing, diagnosis, treatment and prevention of genetic diseases. However, many issues have arisen in the meanwhile. One of the most pressing issues is the lack of standards for reporting genetic test results across different service providers. The First Forum on Standards and Specifications for Clinical Genetic Testing was held to address the issue in Shenzhen, China, on October 28, 2017. Participants, including geneticists, clinicians, and representatives of genetic testing service providers, discussed problems of clinical genetic testing services across in China and shared opinions on principles, challenges, and standards for reporting clinical genetic test results. Here we summarize expert opinions presented at the seminar and report the consensus, which will serve as a basis for the development of standards and guidelines for reporting of clinical genetic testing results, in order to promote the standardization and regulation of genetic testing services in China.