It is a routine task in metabolic engineering to introduce multicomponent pathways into a heterologous host for production of metabolites. However, this process sometimes may take weeks to months due to the lack of standardized genetic tools. Here, we present a method for the design and construction of biological parts based on the native genes and regulatory elements in Saccharomyces cerevisiae. We have developed highly efficient protocols (termed YeastFab Assembly) to synthesize these genetic elements as standardized biological parts, which can be used to assemble transcriptional units in a single-tube reaction. In addition, standardized characterization assays are developed using reporter constructs to calibrate the function of promoters. Furthermore, the assembled transcription units can be either assayed individually or applied to construct multi-gene metabolic pathways, which targets a genomic locus or a receiving plasmid effectively, through a simple in vitro reaction. Finally, using β-carotene biosynthesis pathway as an example, we demonstrate that our method allows us not only to construct and test a metabolic pathway in several days, but also to optimize the production through combinatorial assembly of a pathway using hundreds of regulatory biological parts.

BCAT1 plays a pathogenic role in HCC by causing cell proliferation and chemoresistance. The MYC transcription factor is involved in regulating the transcriptional activity of BCAT1. BCAT1 expression has prognostic significance for the survival of patients with HCC.

A practical approach for adsorption modeling of heterogeneity of single-walled carbon nanotube (SWNT) bundles has been developed. The method integrates experimental analysis with grand canonical Monte Carlo (GCMC) simulation of a small probe molecule, such as nitrogen at 77 K. Using this method, it is possible for one to separately estimate adsorption inside the nanotubes, adsorption on the external surface of the bundles, and adsorptive contributions from the impurities present in samples. By introducing a scaling parameter for adsorption in the internal porous volume of the bundles, the predicted adsorption isotherm results in a near replication of the experimental N 2 adsorption isotherm. We refer to this parameter as the volume fraction of open-ended nanotubes. Our GCMC-assisted experimental characterization method has been applied successfully to several commercial samples obtained from different suppliers, such as MER Corp., Carbon Nanotechnologies Inc., Carbon Solutions Inc., Carbolex Inc., and BuckyUSA. It was found that the volume fraction of openended SWNTs in these samples ranged between 0 and 55%. The majority of the samples were subjected to some purification treatment by the manufacturer and exhibited an already high BET surface area of hundreds of square meters per gram. The near-perfect reproduction of the experimental N 2 (77 K) adsorption isotherm for each of the tested samples shows that our characterization method is not specific to a particular sample and can be extended to most SWNTs successfully. The fraction of open-ended SWNTs cannot otherwise be estimated by visual characterization of the samples because of the large aspect ratio of nanotubes and the spaghetti-like arrangement of the bundles. Our method has the potential to become a standard technique to quantify this structural property of SWNT samples.

The therapeutic potential of baicalein against hepatoma cells was evaluated in vitro and in vivo. In cell viability assays, baicalein showed significant cytotoxicity against the hepatocellular carcinoma cell lines H22, Bel-7404, and Hep G2 and moderate cytotoxicity against immortalized human hepatocytes. Baicalein induced G0/G1-phase arrest in hepatocellular carcinoma cells, inhibited AKT, and promoted the degradation of β-catenin and cyclin D1 without activation of GSK-3β. Furthermore, baicalein significantly inhibited H22 xenograft tumor growth without causing obvious adverse effects on weight or liver and spleen weight indexes in ICR mice. Immunohistochemical analysis showed that the inhibition of tumor growth in baicalein-treated mice was associated with decreased AKT, β-catenin, and cyclin D1 expression ex vivo. Our data indicate that baicalein might regulate cyclin D1 transcription via a β-catenin-dependent mechanism, leading to cell cycle arrest at G0/G1 phase and impaired cancer cell proliferation. These results suggest that baicalein is a potential candidate for the treatment of hepatocellular carcinoma.

Objective To investigate the status of vitamin B12 deficiency in elderly inpatients in the department of neurology.Methods A total number of 827 patients in the department of neurology of Shanghai Punan hospital, from March 2007 to July 2008, were employed in the present study. They were 60 years or older, and the average age was 77.1±7.5 years old. All the patients were diagnosed with no severe hepatic or renal dysfunction, without any usage of vitamin B12 during the previous 3 months before the detection. The levels of serum vitamin B12, folate and homocysteine (Hcy) were evaluated. The patients with vitamin B12 deficiency were screened. The resulting symptoms, positive signs of neurological examination, and the neuroelectricphysiological results were compared between patients with or without vitamin B12 deficiency. Results Vitamin B12 deficiency was found in 163 patients (19.71% of the total patients), and was more prevalent in female than in male patients, also with increased incidences with aging. Patients with low levels of serum vitamin B12 exhibited higher rate of gastrointestinal diseases, while only 9.82% of the vitamin B12 deficient patients had megaloblastic anemia. Symptoms of vitamin B12 deficiency included unsteadily walking in the darkness and hypopallesthesia, and some chronic diseases such as cerebral ischemia, hypertension, Parkinson's disease (Parkinsonism), diabetes mellitus and coronary heart disease. Most of the vitamin B12 deficient patients had neuroelectricphysiological abnormalities. Conclusion Vitamin B12 deficiency is remarkably common in elderly patients in neurology department, with various and atypical clinical manifestations, and the neurological symptoms are more common than megaloblastic anemia symptoms.

BackgroundVolatile anesthetics are widely used in pediatric anesthesia but their potential neurotoxicity raise significant concerns regarding sequelae after anesthesia. However, whether physiological disturbance during anesthetic exposure contributes to such side effects remains unknown. The aim of the current study is to compare the neurotoxic effects of isoflurane and sevoflurane in 14 day old rat pups under spontaneous breathing or ventilated conditions.MethodsPostnatal 14 day rats were assigned to one of five groups: 1) spontaneous breathing (SB) + room air (control, n = 17); 2) SB + isoflurane (n = 35); 3) SB + sevoflurane (n = 37); 4) mechanical ventilation (MV) + isoflurane (n = 29); 5) MV + sevoflurane (n = 32). Anesthetized animal received either 1.7% isoflurane or 2.4% seveoflurane for 4 hours. Arterial blood gases and blood pressure were monitored in the anesthetized groups. Neurodegeneration in the CA3 region of hippocampus was assessed with terminal deoxynucleotidyl transferase-mediated DNA nick-end labeling immediately after exposure. Spatial learning and memory were evaluated with the Morris water maze in other cohorts 14 days after experiments.ResultsMost rats in the SB groups developed physiological disturbance whereas ventilated rats did not but become hyperglycemic. Mortality from anesthesia in the SB groups was significantly higher than that in the MV groups. Cell death in the SB but not MV groups was significantly higher than controls. SB + anesthesia groups performed worse on the Morris water maze behavioral test, but no deficits were found in the MV group compared with the controls.ConclusionsThese findings could suggest that physiological disturbance induced by isoflurane or sevoflurane anesthesia may also contribute to their neurotoxicity.

BackgroundThe present study aimed to determine the accuracy (Z‐value) of non‐invasive prenatal testing (NIPT) results for sex chromosome aneuploidy (SCA) in routine clinical practice.MethodsAmong a cohort of 12505 pregnant females, maternal plasma samples collected from our hospital were utilized for SCA analysis by NIPT detection. The positive samples were validated through an invasive procedure and karyotyping analysis. The predictive value from positive samples in sex chromosomes was compared to analyze the accuracy of the Z‐value.ResultsThere were 65 females with sex chromosome abnormalities within 12,505 pregnant females in the NIPT detection, which was validated by karyotype analysis of amniotic fluid puncture through sequencing, as well as bioinformatics analysis, with 18 true‐positive samples. The true‐positive results with 45,X, 47,XXY, 47,XXX and 47,XYY karyotypes predicted by NIPT were 14.29%, 50.00%, 66.67% and 71.43%, respectively. Among sex chromosome cases, the findings indicated that positive NIPT results with Z ≥ 9 show a higher accuracy.ConclusionsThe findings of the present study demonstrate that the positive predictive value of NIPT for sex chromosome abnormalities is distinctive. The positive predictive value was highest for 47,XYY and lowest for 45,X. Additionally, the Z‐value results are considered to be correlated with the accuracy of NIPT, although further studies need to be made.

Acoustic droplet ejection (ADE) technology uses focused acoustic energy to transfer nanoliter-scale liquid droplets with high precision and accuracy. This noncontact, tipless, low-volume dispensing technology minimizes the possibility of cross-contamination and potentially reduces the costs of reagents and consumables. To date, acoustic dispensers have mainly been used in screening libraries of compounds. In this paper, we describe the first application of this powerful technology to the rapidly developing field of synthetic biology, for DNA synthesis and assembly at the nanoliter scale using a Labcyte Echo 550 acoustic dispenser. We were able to successfully downscale PCRs and the popular one-pot DNA assembly methods, Golden Gate and Gibson assemblies, from the microliter to the nanoliter scale with high assembly efficiency, which effectively cut the reagent cost by 20- to 100-fold. We envision that acoustic dispensing will become an instrumental technology in synthetic biology, in particular in the era of DNA foundries.