Bioconversion of C1 gases and genetic engineering modification of gas-utilizing microorganisms / 生物工程学报

C1 gases including CO, CO2 and CH4, are mainly derived from terrestrial biological activities, industrial waste gas and gasification syngas. Particularly, CO2 and CH4 are two of the most important greenhouse gases contributing to climate change. Bioconversion of C1 gases is not only a promising solution to addressing the problem of waste gases emission, but also a novel route to produce fuels or chemicals. In the past few years, C1-gas-utilizing microorganisms have drawn much attention and a variety of gene-editing technologies have been applied to improve their product yields or to expand product portfolios. This article reviewed the biological characteristics, aerobic or anaerobic metabolic pathways as well as the metabolic products of methanotrophs, autotrophic acetogens, and carboxydotrophic bacteria. In addition, gene-editing technologies (e.g. gene interruption technology using homologous recombination, group Ⅱ intron ClosTron technology, CRISPR/Cas gene editing and phage recombinase-mediated efficient integration of large DNA fragments) and their application in these C1-gas-utilizing microorganisms were also summarized.

Relationship between failed mechanism of sevoflurane postconditioning-induced myocardial protec-tion and dynamin-related protein 1 activity in diabetic rats / 中华麻醉学杂志

Objective To evaluate the relationship between the failed mechanism of sevoflurane postconditioning-induced myocardial protection and the activity of dynamin-related protein 1(Drp1)in dia-betic rats. Methods Pathogen-free healthy adult male Sprague-Dawley rats, weighing 220-280 g, in which diabetes mellitus was induced by combination of high-fat and high-sucrose diet and intraperitoneal injection of streptozotoein 30 mg∕kg, were studied.Sixty rats with diabetes mellitus were divided into 5 groups(n=12 each)using a random number table: sham operation group(group Sham), myocardial ischemia∕reperfusion (I∕R)group(group I∕R), sevoflurane postconditioning group(group SP), Drp1 inhibitor mitochondrial division inhibitor-1(Mdivi-1)group(group M)and Mdivi-1 plus sevoflurane postconditioning group(group M-SP). Myocardial I∕R was induced by occluding the left anterior descending branch of the coronary artery for 30 min followed by 120 min reperfusion except for group Sham. Mdivi-1 1.2 mg∕kg was intraperito-neally injected at 15 min before ischemia in M and M-SP groups, and 2.5% sevoflurane was inhaled starting from 5 min of reperfusion in SP and M-SP groups. Blood samples were collected from the right internal jugular vein at 120 min of reperfusion for measurement of serum cardiac troponin I(cTnI)concentrations(by en-zyme-linked immunosorbent assay). Rats were then sacrificed and myocardial specimens were obtained for de-termination of the myocardial infarct size(by TTC), cell apoptosis(by TUNEL), expression of Bax, Bcl-2 and activated caspase-3(by Western blot)and nicotinamide adenine dinucleotide(NAD+)content(by spectrophotometry). Apoptosis index(AI)and Bax∕Bcl-2 ratio were calculated. Results Compared with group Sham, the percentage of myocardial infarct size, serum concentration of cTnI, AI and Bax∕Bcl-2 ratio were significantly increased, the expression of activated caspase-3 was up-regulated, and the NAD+content was decreased in the other four groups(P<0.05). Compared with group I∕R, the percentage of myocardial infarct size, serum concentration of cTnI, AI and Bax∕Bcl-2 ratio were significantly decreased, the expres-sion of activated caspase-3 was down-regulated, and the NAD+content was increased in group M-SP(P<0.05), and no significant change was found in the parameters mentioned above in SP and M groups(P>0.05). Compared with group SP, the percentage of myocardial infarct size, serum concentration of cTnI, AI and Bax∕Bcl-2 ratio were significantly decreased, the expression of activated caspase-3 was down-regulated, and the NAD+content was decreased in group M-SP(P<0.05), and no significant change was found in the parameters mentioned above in group M(P>0.05). ConclusionThe failed mechanism of sevoflurane postconditioning-induced myocardial protection may be related to the activity of Drp1 in diabetic rats.

Intracerebroventricular transplantation of human amniotic epithelial cells ameliorates spatial memory deficit in the doubly transgenic mice coexpressing APPswe and PS1ΔE9-deleted genes / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Human amniotic epithelial cells (HAECs), which have characteristics of both embryonic and pluripotent stem cells, are therefore a candidate in cell therapy without creating legal or ethical problems. In the present study, we aimed to investigate the effects of intracerebroventricular transplantation of HAECs on doubly transgenic mice of Alzheimer's disease (AD) coexpressing presenilin-1 (PS1) and mutant Sweden amyloid precursor protein (APPswe) genes.</p><p><b>METHODS</b>The offspring mice genotypes were detected using PCR identification of APPswe and PS1 gene. The doubly transgenic (TG) mice (n = 20) and wild-type (WT) mice (n = 20) were randomly divided into two groups respectively: the transplantation group treated with HAECs and the control group with phosphate buffered saline. Six radial arm water maze test was used to assess the spatial memory in the TG and WT mice. Amyloid plaques and neurofibrillary tangles were analyzed using congo red and acid-silver methenamine staining respectively. Immunofluorescence cytochemistry was used to track the survival of HAECs. Immunohistochemistry was used to determine the expression of octamer-binding protein 4 (Oct-4) and Nanog in the HAECs. High performance liquid chromatography was used to measure acetylcholine in hippocampus. The density of cholinergic neurons in basal forebrain and nerve fibers in hippocampus was measured using acetylcholinesterase staining.</p><p><b>RESULTS</b>Amyloid deposition occurred in hippocampus and frontal cortex in the double TG mice aged 8 months, but not in WT mice. The results also showed that transplanted HAECs can survive for at least 8 weeks and migrate to the third ventricle without immune rejection. The graft HAECs can also express the specific marker Oct-4 and Nanog of stem cell. Compared with the control group, transplantation of HAECs can not only significantly improve the spatial memory of the TG mice, but also increase acetylcholine concentration and the number of hippocampal cholinergic neurites.</p><p><b>CONCLUSIONS</b>These results demonstrate that intracerebroventricular transplantation of HAECs can improve the spatial memory of the double TG mice. The higher content of acetylcholine in hippocampus released by more survived cholinergic neurites is one of the causes of this improvement.</p>

Study on association between vitamin D receptor gene polymorphisms and the outcomes of HBV infection / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To explore whether the vitamin D receptor gene (VDR) polymorphisms are associated with the outcomes of hepatitis B virus (HBV) infection in Chinese Han population.</p><p><b>METHODS</b>Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to detect the polymorphisms of Fok I locus in exon 2 and Taq I locus in exon 9 of VDR gene. One hundred and eighty-four chronic hepatitis B patients and 205 asymptomatic HBV carriers were recruited to make the comparison of frequencies of genotype and haplotype of the VDR gene between the patients and the carriers.</p><p><b>RESULTS</b>The univariate analysis showed a significant difference in Fok I polymorphism between chronic hepatitis B patients group and asymptomatic HBV carriers group. The FF genotype frequency in chronic hepatitis B patients group was 44.6%,higher than 31.7% in asymptomatic HBV carriers group (P<0.05). After adjusting the confounders by multiple logistic regression analysis, the result still showed a significant difference in Fok I site polymorphism between chronic hepatitis B patients group and asymptomatic HBV carriers group (OR=1.95, P<0.05). The FT haplotype frequency in chronic hepatitis B patients group was higher than that in asymptomatic HBV carriers group (OR=1.45, P<0.05). The fT haplotype frequency in chronic hepatitis B patients group was lower than that in asymptomatic HBV carriers group (OR=0.72, P<0.05).</p><p><b>CONCLUSION</b>VDR gene polymorphism may be an influence factor of genetic susceptibility to HBV infection.</p>

A brief report on effect of rhG-CSF in treating leukopenia after radio-and chemo-therapy of patients with breast cancer / 中国实验血液学杂志

The study was to observe the effect of rhG-CSF (lishengsu) in treating leukopenia caused by radiotherapy and chemotherapy in patients with breast cancer. 100 cases of breast cancer received modified radical mastectomy were randomized into two groups with the same treatment of one cycle chemotherapy using the protocol of CAF at two weeks after the operations and then radiotherapy. The patients in treated group received rhG-CSF 75 micro g per day s.c. for 5 - 7 days constantly, and additional 3 - 5 days according to leukopenia during radiotherapy. The patients in control group did not receive rhG-CSF during the chemo- and radio-therapy. The results shows that nadir of WBC and neutrophil counts in the treated group was higher than that in control significantly. In conclusion, effect of lishengsu on leucopenia in process of chemotherapy and radiotherapy shows definite therapeutic effect, the side effects are not remarkable.