Advances on microbial synthesis of L-proline and trans-4-hydroxy-L-proline / 生物工程学报

L-proline (L-Pro) is the only imino acid among the 20 amino acids that constitute biological proteins, and its main hydroxylated product is trans-4-hydroxy-L-proline (T-4-Hyp). Both of them have unique biological activities and play important roles in biomedicine, food and beauty industry. With the in-depth exploration of the functions of L-Pro and T-4-Hyp, the demand for them is gradually increasing. Traditional methods of biological extraction and chemical synthesis are unable to meet the demand of "green, environmental protection and high efficiency". In recent years, synthetic biology has developed rapidly. Through the intensive analysis of the synthetic pathways of L-Pro and T-4-Hyp, microbial cell factories were constructed for large-scale production, which opened a new chapter for the green and efficient production of L-Pro and T-4-Hyp. This paper reviews the application and production methods of L-Pro and T-4-Hyp, the metabolic pathways for microbial synthesis of L-Pro and T-4-Hyp, and the engineering strategies and advances on microbial production of L-Pro and T-4-Hyp, aiming to provide a theoretical basis for the "green bio-manufacturing" of L-Pro and T-4-Hyp and promote their industrial production.

Comparison of the efficiency and safety of two different treatments in middle cerebral artery stenosis / 重庆医学

Objective To evaluate the efficacy and safety of percutaneous transluminal angioplasty and stenting of intravascular stenting (PTAS) and internal medicine in the treatment of secondary severe stroke in young patients with severe symptomatic middle cerebral artery stenosis.Methods The clinical data of 77 cases with severe symptomatic middle cerebral artery stenosis(ste nosis rate≥70％)confirmed by digital subtraction angiography(DSA) were collected retrospectively in our hospital from January 2011 to June 2015.The patients were divided into PTAS group and medical treatment group,and the data were collected including the modified Rankin Score (mRS score) at admission,the US National Institutes of Health Stroke volume neurological impairments score (NIHSS score)at admission,as well as mRS score,the recurrence of ischemic stroke,death and intracerebral hemorrhage within 1 year.Results The primary end-point rates within 30 days after enrollment in PTAS group and medical treatment group were 0％ and 5.77％ respectively,and the stroke recurrence rates within 1 year were 4.35％ and 13.46％ respectively,The differ ence was not statistically significant(P＞0.05).Meanwhile,there was no death and intracerebral hemorrhage in both two groups.The rates of mRS≤1 were 91.30 ％ and 69.23 ％ respectively in PTAS group and medical treatment group,and the difference was statistically significant (P＜0.05).The rates of mRS≤2 were 95.65 ％ and 84.62 ％ respectively in PTAS group and medical treat ment group,and the difference was not statistically significant(P＞0.05).Conclusion PTAS is safe for the severe symptomatic middle cerebral artery stenosis,and is more efficient in dectasing the risk of recurrent stroke in young population compared with medical treatment.

Effect of hypertonic saline on permeability of blood-brain barrier in a rat model of intracerebral hemorrhage / 中华麻醉学杂志

Objective To investigate the effect of hypertonic saline (HS) on the permeability of blood-brain barrier in a rat model of intracerebral hemorrhage (ICH).Methods Sixty healthy male Sprague-Dawley rats, aged 8 weeks, weighing 260-300 g, were randomly divided into 4 groups (n=15 each) using a random number table: sham operation group (group S), sham operation+HS group (group HS) ,ICH group, and ICH+HS group.ICH was commonly induced in anesthetized rats by intraparenchymal injection of autologous blood 50 μ1.The equal volume of normal saline was given instead in group S.The neurologic deficits were scored on a five-point scale, and a score of 1-3 indicated successful establishment of the model.At 48 h after establishment of the model, the rats were sacrificed, and brains were removed for determination of brain water content, expression of occludin in brain tissues (by Western blot) , and Evans blue content.Results Compared with group S, the brain water content and Evans blue content were significantly increased, and the expression of occludin was down-regulated in ICH and ICH+HS groups, and no significant change was found in the indices mentioned above in group S+HS.Compared with group ICH,the brain water content and Evans blue content were significantly decreased, and the expression of occludin was up-regulated in group ICH +HS.Conclusion HS can inhibit increase in the permeability of bloodbrain barrier, and reduce the cerebral edema in a rat model of ICH.