Controlled biosynthesis of odd-chain fuels and chemicals via engineered modular metabolic pathways

Microbial systems are being increasingly developed as production hosts for a wide variety of chemical compounds. Broader adoption of microbial synthesis is hampered by a limited number of high-yielding natural pathways for molecules with the desired physical properties, as well as the difficulty in functionally assembling complex biosynthetic pathways in heterologous hosts. Here, we address both of these challenges by reporting the adaptation of the butanol biosynthetic pathway for the synthesis of odd-chain molecules and the development of a complementary modular toolkit to facilitate pathway construction, characterization, and optimization in engineered Escherichia coli. The modular feature of our pathway enables multientry and multiexit biosynthesis of various odd-chain compounds at high efficiency. By varying combinations of the pathway and toolkit enzymes, we demonstrate controlled production of propionate, trans-2-pentenoate, valerate, and pentanol, compounds with applications that include biofuels, antibiotics, biopolymers, and aroma chemicals. Importantly, and in contrast to a previously used method to identify limitations in heterologous amorphadiene production, our bypass strategy was effective even without the presence of freely membrane-diffusible substrates. This approach should prove useful for optimization of other pathways that use CoA-derivatized intermediates, including fatty acid β-oxidation and the mevalonate pathway for isoprenoid synthesis.     

(1)H and (31)P NMR studies indicate reduced bile constituents in patients with biliary obstruction and infection

Patients with extrahepatic biliary obstruction present with impairment of the normal bile flow, with jaundice and cholangitis as common complications. (1)H and (31)P NMR quantitative analysis of bile specimens from patients with extrahepatic biliary obstruction (n = 80) (with/without jaundice and cholangitis separately and together) was carried out for the chief biliary constituents to determine the relationship between biliary constituents and jaundice (serum bilirubin concentration >or=1.0 mg/dL) and cholangitis (total leucocyte count >11,000 cells/mm(3) and/or fever >38.5 degrees C with/without bile culture positivity). Compared with controls (patients without jaundice and cholangitis), median indices of the chief biliary constituents (total bile acids, cholesterol, phosphatidylcholine and inorganic phosphate) were significantly suppressed in patients with cholangitis and/or jaundice. Quantities of total bile acids, cholesterol and phosphatidylcholine correlated negatively with the quantity of bilirubin and with cholangitis, i.e. total leucocyte count. Suppression of biliary constituents correlated significantly with the severity of jaundice and cholangitis. The decrease in biliary constituents in the presence of jaundice and cholangitis is possibly the result of downregulation of the function of transporters located at the canalicular side of hepatocytes, leading to their suppressed indices in bile. This information may have implications in the examination of bile for clinical studies.     

Effect of an Extract from the Egyptian Sea Cucumber,Bohadschia marmorata,on Methotrexate-Induced Hepatorenal Toxicity in Male Mice

Background: The sea cucumber, Bohadschia marmorata, is a marine echinoderm consumed and used as a medication. Extract of this species displays a broad spectrum of bioactivity, such as antifungal, antibacterial, immunomodulatory, and cytotoxic properties. This investigation explored sea cucumber extract for hepatorenal protection against the toxicity of methotrexate (MTX). Methods: Four groups of mice were divided into G1: control, G2: MTX treated, G3: B. marmorata extract-treated daily for 14 days, and G4: B. marmorata extract and MTX treated. Results and Conclusions: Biochemical analysis and histopathological examination of liver tissue showed that administration of MTX increased serum levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT), lowered levels of serum albumin, total protein, Superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH). Administration of B. marmorata extract to MTX- injected mice significantly reversed the increase in serum levels of liver enzymes and induced a significant elevation in serum albumin and total protein levels. SOD, CAT, and GSH levels returned to nearly normal levels. Histopathological examination indicated fewer signs of toxicity in liver and kidney tissues of mice treated with both extract and MTX compared to MTX treatment alone. An extract of B. marmorata will protect mice from hepatorenal toxicity induced by MTX.     

支架植入术对颈动脉狭窄患者血管再通及神经生化标志物的影响

目的 研究支架植入术对颈动脉狭窄患者血管再通及神经生化物的影响。方法 选取2016年1月~2020年1月我院收治的61例颈动脉狭窄患者,将患者采用随机数字表法分为手术干预组（n=30）和对照组（n=31）,对照组接受内科常规颈动脉狭窄手术治疗;手术干预组接受支架植入术治疗。对比两组患者治疗前和治疗四周后神经生化物[中枢神经特异蛋白（S100β）、人脑髓鞘碱性蛋白（MBP）、神经元特异性烯醇化酶（NSE）]、氧化应激因子[超氧化物歧化酶（SOD）,丙二醛（MDA）]、及认知功能评估;对比两组患者治疗期间出现的不良反应;对比两组患者治疗3、6个月后血管通畅情况。结果 治疗后,相比于对照组,手术干预组S100β、MBP、NSE显著更低（P<0.05）;治疗后,相比于对照组,手术干预组SOD显著更高,MDA显著更低（P<0.05）;治疗后,相比于对照组,手术干预组MOCA评分显著更高（P<0.05）。结论 支架植入术能够明显改善患者神经生化物、氧化应激因子和认知功能,提高术后血管再通率,且安全性较高。     

酒精性脂肪肝与非酒精性脂肪肝患者生化指标的对比分析

目的：探讨酒精性脂肪肝与非酒精性脂肪肝特异性的鉴别指标．以指导临床诊断。方法：对38例酒精性脂肪肝患者及151例非酒精性脂肪肝患者的血清酶、血脂、尿酸、血糖、红细胞压积等指标进行测定及分析。结果：酒精性脂肪肝组谷草转氨酶(AST)、谷草转氨酶／谷丙转氨酶(AST／ALT02)、γ-谷氨酰转肽酶(GGT)、尿酸(UA)异常的百分数分别为73．7％、34．2％、47．4％、60．5％。非酒精性脂肪肝组分别为27．8％、14．6％、20．5％、35．1％。两组相比差异有统计学意义。结论：AST、AST／ALT(≥2)、GGT、UA等指标可能是鉴别酒精性脂肪肝与非酒精性脂肪肝有效的临床辅助诊断指标。     

MAHARISHI AMRIT KALASH REJUVENATES AGEING CENTRAL NERVOUS SYSTEM'S ANTIOXIDANT DEFENCE SYSTEM: AN IN VIVO STUDY

The oxygen-free radical involvement in various deteriorative processes and in ageing is unquestionably established. In the present study age-related changes in antioxidant enzyme activity in the different regions of CNS of 10-month and 32-month-old guinea pigs were studied. Maharishi Amrit Kalash has shown promise in inhibiting the in vitro and in vivo lipid peroxidation. Therefore in the present study the effect of MAK on the activity of antioxidant enzymes was checked. Our results indicate that the activity of superoxide dismutase and glutathione peroxidase, was found to be reduced (P<0.05) in all the regions of CNS studied, The activities of catalase declined significantly only in the cerebral cortex, hypothalamus and the cerebellum. Whereas glutathione reductase activity declined in the cerebral cortex and hypothalamus. It is concluded that the age-related decline in the activities of antioxidant enzymes is region-specific as well as enzyme-specific. The endogenous lipid peroxide was found to be increased significantly (P<0.05) in the 32-month-old animals. Whereas the lipid peroxidation after incubating the tissue homogenate in the air was found to be decreased (P<0.05) in the older animals. The results indicate that the accumulation of lipid peroxides take place with age but the susceptibility of lipid peroxidation decreases in the older animals. The treatment of MAK 500 mg kg⁻¹body wt. for 2 months could augment the activities of antioxidant enzymes (P<0.05). The effect of MAK was more pronounced in older than younger animals. It is concluded that the MAK can be used in compensating the decline in the activities of antioxidant enzymes in CNS and thereby it reduces the risks of lipid peroxidation.pc 1999 Academic Press@p$hr     

Tailored fatty acid synthesis via dynamic control of fatty acid elongation

Medium-chain fatty acids (MCFAs, 4–12 carbons) are valuable as precursors to industrial chemicals and biofuels, but are not canonical products of microbial fatty acid synthesis. We engineered microbial production of the full range of even- and odd-chain–length MCFAs and found that MCFA production is limited by rapid, irreversible elongation of their acyl-ACP precursors. To address this limitation, we programmed an essential ketoacyl synthase to degrade in response to a chemical inducer, thereby slowing acyl-ACP elongation and redirecting flux from phospholipid synthesis to MCFA production. Our results show that induced protein degradation can be used to dynamically alter metabolic flux, and thereby increase the yield of a desired compound. The strategy reported herein should be widely useful in a range of metabolic engineering applications in which essential enzymes divert flux away from a desired product, as well as in the production of polyketides, bioplastics, and other recursively synthesized hydrocarbons for which chain-length control is desired.     

Evaluation of the bio-activity of marine cyanobacteria on some biochemical parameters of rat serum

Wistar strain male albino rats were administered with the water soluble fraction of the ethanol extract of 12 different strains of marine cyanobacteria to understand their effect on the biochemical composition of the blood namely, serum levels of proteins, total free sugars, cholesterol, calcium, magnesium, sodium and potassium and the levels of activity of the enzymes glutamic pyruvic transaminase, glutamate oxalacetate transaminase, acid phosphatase and alkaline phosphatase. The results suggest the potential application of some of the marine cyanobacteria as pharmaceuticals/modulators of the regulatory system, though a few strains exerted minor toxic effects.