Removing the by-products acetic acid and NH4 + from the L-tryptophan broth by vacuum thin film evaporation during L-tryptophan production

Background: During L-tryptophan production by Escherichia coli, the by-products, acetic acid and NH4 +, accumulate in the fermentation broth, resulting in inhibited cell growth and activity and decreased L-tryptophan production. To improve the L-tryptophan yield and glucose conversion rate, acetic acid and NH4 + were removed under low-temperature vacuum conditions by vacuum scraper concentrator evaporation; the fermentation broth after evaporation was pressed into another fermenter to continue fermentation. To increase the volatilisation rate of acetic acid and NH4 + and reduce damage to bacteria during evaporation, different vacuum evaporation conditions were studied. Results: The optimum operating conditions were as follows: vacuum degree, 720 mm Hg; concentration ratio, 10%; temperature, 60°C; and feeding rate, 300 mL/min. The biomass yield of the control fermentation (CF) and fermentation by vacuum evaporation (VEF) broths was 55.1 g/L and 58.3 g/L at 38 h, respectively, (an increase of 5.8%); the living biomass yield increased from 8.9 (CF) to 10.2 pF (VEF; an increase of 14.6%). L-tryptophan production increased from 50.2 g/L (CF) to 60.2 g/L (VEF) (an increase of 19.9%), and glucose conversion increased from 18.2% (CF) to 19.5% (VEF; an increase of 7.1%). The acetic acid concentrations were 2.74 g/L and 6.70 g/L, and the NH4 + concentrations were 85.3 mmol/L and 130.9 mmol/L in VEF and CF broths, respectively. Conclusions: The acetic acid and NH4 + in the fermentation broth were quickly removed using the vacuum scraper concentrator, which reduced bacterial inhibition, enhanced bacterial activity, and improved the production of L-tryptophan and glucose conversion rate.

Ultrasonic 3D reconstruction and measurement of lacrimal sac in normal adult Chinese population / Reconstrucción 3D con ultrasonido y mediciones del saco lagrimal en una población china de adultos normales

To apply the ultrasonic 3D reconstruction method to measure the anatomic image data of lacrimal sac in the normal adult Chinese population, providing imaging anatomical basis for the clinical diagnosis and treatment of lacrimal duct diseases. 80 volunteers without lacrimal duct diseases were enrolled. The GE Voluson E8 ultrasonic diagnostic apparatus was used, with gynecological intracavitary probe (frequency: 5 ~ 12MHz) for the examination and measurement. Each datum was repeated three times for the average value. Among the 80 eyes, the lacrimal sacs of 74 eyes exhibited the clear imaging, with the imaging rate as 92.5 %. the vertical diameter of lacrimal sac cavity (LSC): 13.3±2.2 mm; anteroposterior diameter: 6.0±1.1 mm; trans diameter: 4.9±0.9 mm; the vertical distance from the sac cavity top to the skin surface: 6.3±0.12 mm, the vertical distance from the sac cavity bottom to the skin surface: 6.5±0.11 mm; the distance from the angular artery to the medial canthus: 7.8±0.05 mm; the vertical distance from the angular artery to the skin surface: 7.7±0.08 mm. The lacrimal sac and angular artery in the adults could be shown clearly in ultrasonic 3D reconstruction, the accumulated anatomical parameters could provide the instructive meanings towards the clinical diagnosis and treatment of lacrimal diseases.

El objetivo de este estudio consistió en aplicar el método de reconstrucción 3D de ultrasonidos para medir los datos de las imágenes anatómicas del saco lagrimal en una población china adulta normal, proporcionando imágenes con base anatómica para el diagnóstico clínico y el tratamiento de las enfermedades de los conductos lagrimales. La muestra consistió en 80 voluntarios sin enfermedades de los conductos lagrimales. Se utilizó el aparato de ultrasonido GE Voluson E8, con una sonda intracavitaria ginecológica (frecuencia: 5 ~ 12 MHz) para realizar el examen y la medición. Cada dato se repitió tres veces para obtener el valor medio. De los 80 ojos, los sacos lagrimales de 74 ojos mostraron una imagen clara, siendo la tasa de formación de imágenes del 92,5 %. Se realizaron mediciones: diámetro vertical de la cavidad del saco lagrimal (LSC): 13,3 ± 2,2 mm; diámetro anteroposterior: 6,0 ± 1,1 mm; diámetro transversal: 4,9 ± 0,9 mm; distancia vertical desde la porción superior de la cavidad del saco lagrimal hasta la superficie de la piel: 6,3 ± 0,12 mm, distancia vertical desde el fondo de la cavidad del saco lagrimal hasta la superficie de la piel: 6,5 ± 0,11 mm; distancia desde la arteria angular al canto medial: 7,8 ± 0,05 mm; distancia vertical desde la arteria angular a la superficie de la piel: 7,7 ± 0,08 mm. El saco lagrimal y la arteria angular en los adultos se podría demostrar claramente en la reconstrucción 3D con ultrasonido. Los parámetros anatómicos acumulados podrían ser de significativo valor para un certero diagnóstico clínico y tratamiento de enfermedades de los sacos lagrimales.

Inhibition effects of tea flower extract on glucose absorption in experimental glucose tolerance mice / 国际药学研究杂志

Objective To study the inhibitory effects of tea flower extract (TFE) on α-glucosidase and glucose intestinal absorption. Methods Three different postprandial hyperglycemia models (2 g/kg glucose, 4 g/kg sucrose, and 6 g/kg starch) were used, with 8 mice in each group. Oral administration of 150 or 300 mg/kg of TFE, 6.25 mg/kg of acarbose, or water was performed on mice 1 day and 30 mins before the oral administration of 2 g/kg glucose, 4 g/kg sucrose, and 6 g/kg starch at 10 ml/kg of body weight. Blood glucose levels were analyzed chronologically to evaluate the effect of TFE. In vitro studies were also performed to study the inhibitory effects of TFE on α-glucosidase and small intestinal mucosa glycosidase.

Development of SNP multiplexes utilizing universal reporter primers for forensic purposes / 法医学杂志

OBJECTIVE@#To establish a simple, fast and economical technique for multiplex-typing SNPs and to explore its potential forensic application.@*METHODS@#Five Y-SNP loci (IMS-JST164520, IMS-JST021354, IMS-JST003305, M119 and M134) were selected and the allele specific primers of each locus were designed with the universal reporter primers tailed at their 5' end. Alleles of these loci were amplified first by allele specific primers, then amplified by universal reporter primers tagged by fluorescent dye.@*RESULTS@#A fluorescent-multiplex PCR system of the five Y-SNP loci was established. The typing results showed that two different colors of product peaks denoted two different alleles of a SNP locus, and the fragment sizes of alleles among different SNP loci were different. The haplotype diversity of these five loci was estimated to be 0.8655 in Wuhan Han population.@*CONCLUSION@#The multiplex-typing SNPs based on the universal reporter primers is a simple, fast, and economical technique, and may have good application value in forensic medicine.

Validation of Differential Extraction Kit in forensic sexual assault cases / 法医学杂志

OBJECTIVE@#To evaluate the validity of Differential Extraction Kit in isolating spermatozoa and epithelial cell DNA from mixture samples.@*METHODS@#Selective lysis of spermatid and epithelial cells combined with paramagnetic particle method were applied to extract the DNA from the mock samples under controlled conditions and forensic case samples, and template DNA were analyzed by STR genotype method.@*RESULTS@#This Differential Extraction Kit is efficient to obtain high quality spermatid and epithelial cell DNA from the mixture samples with different proportion of sperm to epithelial cell.@*CONCLUSION@#The Differential Extraction Kit can be applied in DNA extraction for mixed stain from forensic sexual assault samples.

A reviewing for profiling of highly degraded remains / 法医学杂志

It's always a challenge to type from highly degraded biological remains. PCR-based STR genotyping is helpful and valuable for such degraded samples like bones, teeth et al, but the typing results are sometimes unstable or wrong. Here the methods for solving the problems and improving reproducibility are reviewed.

Serial pathologic changes in livers of Tree shrews and Macaca assamensises infected with human Hepatitis B virus / 中华实验和临床病毒学杂志

<p><b>BACKGROUND</b>To serially observe the pathologic changes in livers of tree shrews and macaca assamensises infected with HHBV.</p><p><b>METHODS</b>10 adult tree shrews and 28 macaca assamensises were inoculated with HBV rich human sera. The liver of the animals were regularly biopsied. The liver samples were examined histopathologically by HE staining. Some samples were stained for HBsAg by immunohistochemistry (IH), and HBV DNA by in situ hybridization (ISH).</p><p><b>RESULTS</b>HBsAg in 80% of tree shrews infected with HHBV can be detected by IH, HBV DNA in 50% of those can be found by ISH.The positive rates of HBsAg in macaca assamensises' livers were 25% by IH, none HBV DNA was detected.</p><p><b>CONCLUSION</b>The tree shrew model seems to be applicable for the research of human hepatitis B.</p>

Protective effects of tacrine and donepezil against staurosporine-induced apoptotic death / 药学学报

<p><b>AIM</b>To study whether tacrine and donepezil can prevent cell apoptosis induced by staurosporine in NG108-15 and Hela cell lines.</p><p><b>METHODS</b>MTT assay was used to examine if staurosporine impairs cell metabolism. Phase-contrast and fluorescence microscope were used to examine cell morphological changes. DNA was isolated and electrophoretically separated on 1% agarose gel to observe if there were DNA fragments. Western blot was made to analyse protein levels of anti-apoptotic Bcl-2 and proapoptotic Bax.</p><p><b>RESULTS</b>NG108-15 cells treated with 0.1 mumol.L-1 staurosporine for 12-24 hours exhibited marked cell death and DNA fragmentation. Pre-treatment with 0.1 mmol.L-1 tacrine provided approximately 40% protective effect and resulted in obvious inhibition or delay of DNA fragmentation. Moreover, NG108-15 cells treated with tacrine became elongated and polarized, and showed longer processes than control cells. Pretreatment with 0.1 mmol.L-1 tacrine significantly increased the expression of Bcl-2 protein level and delayed the staurosporine-induced increase of Bax protein expression. However, donepezil did not show any protective effect on the cell impairment induced by staurosporine in NG108-15 cells. In Hela cells 0.1 mumol.L-1 staurosporine also induced significant cell injury, but pretreatment with tacrine and donepezil did not provide any obvious protective effect against this cell damage.</p><p><b>CONCLUSION</b>Donepezil did not provide obvious protective effect against apoptosis, and protective effects of tacrine might not be mediated through AChE inhibition. Protective effects of tacrine against staurosporine-induced injury might be selective to different cells.</p>

Expression of transforming growth factor-?_2 and changes of lens epithelial cells in age-related nuclear and cortex cataract / 中华老年医学杂志

Objective To investigate the pathogenesis of age-related cortex and nuclear cataract.Methods The levels of transforming growth factor-?_2 (TGF-?_2)mRNA,proliferating cell nuclear antigen (PCNA),ratio of Bcl-2/Bax,fibronection (FN),vimentin and the density of lens epithelial cells (LECs) were measured and compared among age-related nuclear cataract,cortex cataract and normal LECs.Results The ratio of TGF-?_2 mRNA expression/?-actin expression,the levels of PCNA protein,Bax and Bcl-2 in age-related nuclear cataract(0.16?0.02,16.01,15.97, 16.97)and in cortex cataract (0.27?0.01,1.98,16.93,1.44) were significantly different from those in normal LECs(0.15+0.02,2.43,16.84,6.12),all P