Effect of Imaging Markers on Reperfusion Therapy in Basilar Artery Occlusion.

OBJECTIVE: We aimed to investigate the effectiveness of endovascular therapy (EVT) versus intravenous thrombolysis (IVT) in patients with basilar artery occlusion (BAO), based on the information of advanced imaging. METHODS: We analyzed data of stroke patients with radiologically confirmed BAO within 24 hours. BAO subjects were categorized into "top-of-the-basilar" syndrome (TOBS) and other types. An initial infarct size of <70ml and a ratio of ischemic tissue to infarct volume of ≥1.8 was defined as "target mismatch." The primary outcome was a good outcome, defined as a modified Rankin Scale score of 0 to 3 at 3 months. Propensity score adjustment and inverse probability of treatment weighting (IPTW) propensity score methods were used. RESULTS: Among 474 BAO patients, 93 (19.6%) were treated with IVT prior to EVT, 91 (19.2%) were treated with IVT alone, 95 (20.0%) were treated with EVT alone, and 195 (41.1%) were treated with antithrombotic therapy. In IPTW analyses, we found no benefit of EVT over IVT for good outcome in either TOBS patients (odds ratio = 1.08, 95% confidence interval [CI] = 0.88-1.31) or those with other types (odds ratio = 1.13, 95% CI = 0.94-1.36). However, in patients with other types, if there existed a target mismatch, EVT was independently related to good outcome (odds ratio = 1.46, 95% CI = 1.17-1.81). INTERPRETATION: The "target mismatch profile" seems to be a possible candidate selection standard of EVT for those with other types of BAO. Future studies should separate TOBS from other types of BAO, and try to use advanced imaging. ANN NEUROL 2022;92:97-106.

Overexpression of mGDH in Gluconobacter oxydans to improve D-xylonic acid production from corn stover hydrolysate.

BACKGROUND: D-Xylonic acid is a versatile platform chemical with broad potential applications as a water reducer and disperser for cement and as a precursor for 1,4-butanediol and 1,2,4-tributantriol. Microbial production of D-xylonic acid with bacteria such as Gluconobacter oxydans from inexpensive lignocellulosic feedstock is generally regarded as one of the most promising and cost-effective methods for industrial production. However, high substrate concentrations and hydrolysate inhibitors reduce xylonic acid productivity. RESULTS: The D-xylonic acid productivity of G. oxydans DSM2003 was improved by overexpressing the mGDH gene, which encodes membrane-bound glucose dehydrogenase. Using the mutated plasmids based on pBBR1MCS-5 in our previous work, the recombinant strain G. oxydans/pBBR-R3510-mGDH was obtained with a significant improvement in D-xylonic acid production and a strengthened tolerance to hydrolysate inhibitors. The fed-batch biotransformation of D-xylose by this recombinant strain reached a high titer (588.7 g/L), yield (99.4%), and volumetric productivity (8.66 g/L/h). Moreover, up to 246.4 g/L D-xylonic acid was produced directly from corn stover hydrolysate without detoxification at a yield of 98.9% and volumetric productivity of 11.2 g/L/h. In addition, G. oxydans/pBBR-R3510-mGDH exhibited a strong tolerance to typical inhibitors, i.e., formic acid, furfural, and 5-hydroxymethylfurfural. CONCLUSION: Through overexpressing mgdh in G. oxydans, we obtained the recombinant strain G. oxydans/pBBR-R3510-mGDH, and it was capable of efficiently producing xylonic acid from corn stover hydrolysate under high inhibitor concentrations. The high D-xylonic acid productivity of G. oxydans/pBBR-R3510-mGDH made it an attractive choice for biotechnological production.

Modification of an engineered Escherichia coli by a combinatorial strategy to improve 3,4-dihydroxybutyric acid production.

OBJECTIVES: 3,4-Dihydroxybutyric acid (3,4-DHBA) is a multifunctional C4 platform compound widely used for the synthesis of various materials, including pharmaceuticals. Although, a biosynthetic pathway for 3,4-DHBA production has been developed, its low yield still precludes large-scale use. Here, a heterologous four-step biosynthetic pathway was established in recombinant Escherichia coli (E. coli) using a combinatorial strategy. RESULTS: Several aldehyde dehydrogenases (ALDHs) were screened, using in vitro enzyme assays, to identify suitable catalysts for the dehydrogenation of 3,4-dihydroxybutanal (3,4-DHB) to 3,4-DHBA. A pathway containing glucose dehydrogenase (BsGDH) from Bacillus subtilis, D-xylonate dehydratase (YagF) from E. coli, benzoylformate decarboxylase (PpMdlC) from Pseudomonas putida and ALDH was introduced into E. coli, generating 3.04 g/L 3,4-DHBA from D-xylose (0.190 g 3,4-DHBA/g D-xylose). Disruption of competing pathways by deleting xylA, ghrA, ghrB and adhP contributed to an 87% increase in 3,4-DHBA accumulation. Expression of a fusion construct containing PpMdlC and YagF enhanced the 3,4-DHBA titer, producing the highest titer and yield reported thus far (7.71 g/L; 0.482 g 3,4-DHBA/g D-xylose). CONCLUSIONS: These results showed that deleting genes from competing pathways and constructing fusion proteins significantly improved the titer and yield of 3,4-DHBA in engineered E. coli.

Association of Matrix Metalloproteinase-1 and Matrix Metalloproteinase-3 Gene Variants with Ischemic Stroke and Its Subtype.

BACKGROUND: Genetic variations in the genes of matrix metalloproteinases (MMPs) may play an important role in the pathogenesis of ischemic stroke (IS). Here we investigate the association between MMP-1 -1607 1G/2G and MMP-3 -1171 5A/6A genetic polymorphisms and etiological subtypes of IS in the Han Chinese population. METHODS: A total of 640 eligible patients with IS and 637 age- and gender-matched apparently healthy volunteers were enrolled. Subtypes of IS were classified by Trial of Org 10172 in Acute Stroke Treatment criteria. MMP-1 (-1607 1G/2G) and MMP-3 (-1171 5A/6A) polymorphisms were evaluated using polymerase chain reaction-restriction fragment length polymorphism. RESULTS: The frequencies of the 5A/6A + 5A/5A genotypes and 5A allele were significantly higher in patients with IS than in controls (P <.001, P <.001, respectively). No association was found between MMP-1 1G/2G polymorphism and overall IS. In subgroup analyses, MMP-1 1G/2G and 2G/2G genotypes increased the risk of small-artery occlusion (SAO) subtype (multivariate-adjusted, P <.001, P = .002, respectively), and MMP-3 5A/6A + 5A/5A genotypes were related with large-artery atherosclerosis (LAA) subtype (multivariate-adjusted, P <.001). Haplotype analyses indicated that 2G-6A and 1G-5A increased the risk of SAO (multivariate-adjusted, P = .029) and LAA (multivariate-adjusted, P <.001), respectively. CONCLUSIONS: MMP-1 (-1607 1G/2G) and MMP-3 (-1171 5A/6A) polymorphisms may contribute to different subtypes of IS susceptibility.

Overexpression of membrane-bound gluconate-2-dehydrogenase to enhance the production of 2-keto-D-gluconic acid by Gluconobacter oxydans.

BACKGROUND: 2-keto-D-gluconic acid (2KGA) is widely used as a chemical intermediate in the cosmetic, pharmaceutical and environmental industries. Several microbial fermentation processes have been developed for production of 2KGA but these suffer from substrate/product inhibition, byproduct formation and low productivity. In previous work, we showed that 2KGA can be specifically produced from glucose (Glu) or gluconic acid (GA) by resting wild-type Gluconobacter oxydans DSM2003 cells, although substrate concentration was relatively low. In this study, we attempted to improve 2KGA productivity by G. oxydans DSM2003 by overexpressing the ga2dh gene, which encodes the membrane-bound gluconate-2-dehydrogenase enzyme (GA2DH). RESULTS: The ga2dh gene was overexpressed in G. oxydans DSM2003 under the control of three promoters, P tufB , P ga2dh or P ghp0169 , respectively. Among the recombinant strains obtained, G. oxydans_tufB_ga2dh showed a similar growth rate to that of the control strain and displayed the highest specific productivity of 2KGA from GA, which was increased nearly twofold compared with that of the control strain during batch biotransformation. When biocatalysis conditions were optimized, with provision of sufficient oxygen during biotransformation, up to 480 g/L GA was completely utilized over 45 h by resting cells of G. oxydans_tufB_ga2dh and 453.3 g/L 2KGA was produced. A productivity of 10.07 g/L/h and a yield of 95.3 % were obtained. Overexpression of the ga2dh gene also significantly improved the conversion of Glu to 2KGA. Under optimized conditions, 270 g/L Glu was converted to 321 g/L 2KGA over 18 h, with a yield of 99.1 % and a productivity of 17.83 g/L/h. The glucose concentrations during the batch biotransformation and the 2KGA productivities achieved in this study were relatively high compared with the results of previous studies. CONCLUSIONS: This study developed an efficient bacterial strain (G. oxydans_tufB_ga2dh) for the production of 2KGA by overexpressing the ga2dh gene in G. oxydans. Supply of sufficient oxygen enhanced the positive effect of gene overexpression on 2KGA production. Gluconobacter oxydans_tufB_ga2dh is thus a competitive species for use in 2KGA production.

Impact of 5A/6A polymorphism of matrix metalloproteinase-3 on recurrent atherosclerotic ischemic stroke in Chinese.

Little is known about the impact of the 5A/6A polymorphism of matrix metalloproteinase-3 (MMP-3) on recurrence of atherosclerotic ischemic stroke in Chinese. The aim of this study was to investigate the association of MMP-3 serum level and 5A/6A genetic polymorphism with the recurrence of atherosclerotic ischemic stroke in the Chinese Han population. We analyzed 106 large artery atherosclerosis (LAA) recurrent ischemic stroke patients and 545 LAA first onset ischemic stroke patients from January 2009 to June 2014. Serum MMP-3 concentrations were measured with an enzyme-linked immunosorbent assay. The genotypes of MMP-3 promoter polymorphism (-1171 5A/6A) were determined using polymerase chain reaction-restriction fragment length polymorphism. The frequencies of MMP-3 5A/6A+5A/5A (32.08% vs. 21.47%, p = 0.02) genotype and 5A (16.98% vs. 11.01%, p = 0.01) allele in the recurrent group was significantly higher than those in the first onset group. After adjustment for vascular risk factors, multivariate logistic regression analysis suggested that the MMP-3 5A/6A+5A/5A genotype was an independent risk factor for LAA recurrent ischemic stroke (odds ratio [OR], 1.74; 95% confidence interval [CI], 1.09-2.79, p = 0.021). No significant difference was observed for the MMP-3 serum concentrations between the recurrent group and the first onset group (22.23 ± 8.31 vs. 21.49 ± 7.89 ng/ul, t = 0.88, p = 0.38). The MMP-3 (-1171 5A/6A) polymorphism may contribute to LAA recurrent ischemic stroke susceptibility. Analysis of 5A/6A polymorphism in MMP-3 may identify patients at higher risk for LAA ischemic stroke recurrence, who may be selected for intensive preventive therapy.

Analysis of Clinical Characteristics and Influencing Factors of Early Neurological Deterioration in Patients With Mild Stroke by Intravenous Alteplase Therapy.

OBJECTIVES: Thrombolysis treatment for patients with mild stroke is controversial. The aim of our study was to investigate the clinical characteristics and influencing factors of early neurological deterioration (END) in this group of patients. METHODS: A retrospective analysis was performed on ischemic stroke patients with intravenous thrombolysis (IVT) in Wenzhou Central Hospital. Subgroup analyses were performed for the mild stroke group and nonmild stroke group, END group, and non-early neurological deterioration group in mild stroke patients, respectively. RESULTS: A total of 498 patients were included in this study. Compared with the control group, the mild stroke group was younger age, less atrial fibrillation, previous history of stroke and less use of antithrombotic drugs, more dyslipidemia, smoking, and drinking. Small artery occlusion type was more common in mild stroke, cardioembolism and stroke of undetermined etiology type were less. In the mild stroke group, the symptomatic intracerebral hemorrhage (sICH) rate was 2.54%, and the END rate was 16.1%. Predictors of END included systolic blood pressure, blood glucose, cardioembolism subtype, sICH, and large vessel occlusion. In END patients, the sICH rate was 10.53%, and 84.21% of cases started to worsen within 12 hours after IVT. There was no statistically significant difference in the time to exacerbation among different subtypes. CONCLUSIONS: The occurrence of mild stroke in young patients was largely related to unhealthy lifestyles. The incidence of END in mild stroke IVT patients was low, with most occurring within 12 hours of IVT. There were many risk factors for END: large vessel occlusion and hyperglycemia were independent risk factors for END after IVT. sICH was an important but rare risk factor for END.

Identification of a novel ene reductase from Pichia angusta with potential application in (R)-levodione production.

Asymmetric reduction of electronically activated alkenes by ene reductases (ERs) is an attractive approach for the production of enantiopure chiral products. Herein, a novel FMN-binding ene reductase (PaER) from Pichia angusta was heterologously expressed in Escherichia coli BL21(DE3), and the recombinant enzyme was characterized for its biocatalytic properties. PaER displayed optimal activity at 40 °C and pH 7.5, respectively. The purified enzyme was quite stable below 30 °C over a broad pH range of 5.0-10.0. PaER was identified to have a good ability to reduce the C[double bond, length as m-dash]C bond of various α,ß-unsaturated compounds in the presence of NADPH. In addition, PaER exhibited a high reduction rate (k cat = 3.57 s-1) and an excellent stereoselectivity (>99%) for ketoisophorone. Engineered E. coli cells harboring PaER and glucose dehydrogenase (for cofactor regeneration) were employed as biocatalysts for the asymmetric reduction of ketoisophorone. As a result, up to 1000 mM ketoisophorone was completely and enantioselectively converted to (R)-levodione with a >99% ee value in a space-time yield of 460.7 g L-1 d-1. This study provides a great potential biocatalyst for practical synthesis of (R)-levodione.

The Relationship of Methylenetetrahydrofolate Reductase Gene C677T Polymorphism and Ischemic Stroke in Chinese Han Population.

BACKGROUND: The purpose of this study was to investigate the relationship of methylenetetrahydrofolate reductase (MTHFR) gene C677T polymorphism and ischemic stroke Large-artery atherosclerosis (LAA) and Small-artery occlusion (SAO) subtypes in Chinese Han Population. MATERIALS AND METHODS: One hundred and thirty LAA patients and one hundred and fifty-nine SAO patients data were prospectively collected. The control group was one hundred and ninety-eight subjects from the Medical Examination Center in the same period. Plasma homocysteine (Hcy) levels were determined by a double reagent enzymatic cycling method. The genotypes of MTHFR polymorphism (C677T) were determined using polymerase chain reaction-restriction fragment length polymorphism. RESULTS: As compared with the controls, hypertension prevalence, smoking consumption ratio were significantly higher, plasma Hcy levels increased significantly, plasma high-density lipoprotein cholesterol levels were significantly reduced in LAA and SAO groups (P<0.05 for each). Elevated plasma Hcy levels were associated with MTHFR C677T polymorphism (P<0.01). The frequency of C/T+T/T genotypes and T allele in LAA and SAO groups was significantly higher than those in control groups (P<0.01). CONCLUSIONS: The present study suggests that hypertension, smoking, decreasing plasma high-density lipoprotein cholesterol levels and hyperhomocysteinemia (HHcy) are independent risk factors for LAA and SAO subtypes of ischemic stroke in Chinese Han Population. The MTHFR gene C677T C/T+T/T genotypes and T allele increases the risk of LAA and SAO subtypes of ischemic stroke.

Biosynthesis of L-Erythrose by Assembly of Two Key Enzymes in Gluconobacter oxydans.

L-erythrose, a rare aldotetrose, possesses various pharmacological activities. However, efficient L-erythrose production is challenging. Currently, L-erythrose is produced by a two-step fermentation process from erythritol. Here, we describe a novel strategy for the production of L-erythrose in Gluconobacter oxydans (G. oxydans) by localizing the assembly of L-ribose isomerase (L-RI) to membrane-bound sorbitol dehydrogenase (SDH) via the protein-peptide interactions of the PDZ domain and PDZ ligand. To demonstrate this self-assembly, green fluorescent protein (GFP) replaced L-RI and its movement to membrane-bound SDH was observed by fluorescence microscopy. The final L-erythrose production was improved to 23.5 g/L with the stepwise metabolic engineering of G. oxydans, which was 1.4-fold higher than that obtained using coexpression of SDH and L-RI in G. oxydans. This self-assembly strategy shows remarkable potential for further improvement of L-erythrose production.

Association of matrix metalloproteinase-3 gene 5A/6A polymorphism with the recurrence of ischemic stroke: A prospective observational study.

Studies have demonstrated that matrix metalloproteinase-3 (MMP-3) is involved in the development and progression of atherosclerosis. However, there is no information available on the association of MMP-3 5A/6A polymorphism with recurrent ischemic stroke (IS) in different IS subtypes. We investigated the potential associations between MMP-3 serum level and -1171 5A/6A polymorphism and the recurrence of IS in a Chinese population. Consecutive acute first-ever IS patients were enrolled between August 2008 and October 2013. The genotypes of MMP-3 5A/6A polymorphism were determined using polymerase chain reaction-restriction fragment length polymorphism. IS recurrence was monitored after the index event and multivariate Cox proportional hazards model was constructed to identify factors related to future IS recurrence. A total of 1282 eligible patients were enrolled. During a 2-year follow-up period, 157 (12.25%) patients had recurrent events. MMP-3 level was significantly higher in patients with 5A/6A or 5A/5A genotype (22.72±7.29ng/ul) than in patients with 6A/6A genotype (20.48±7.58ng/ul), P<0.001. No interaction between MMP-3 5A/6A polymorphism and the risk of recurrence in total IS patients was found. The variant 5A/6A+5A/5A genotype and the 5A allele were significantly associated with a high risk of recurrence for large-artery atherosclerosis (LAA) (multivariate-adjusted, P=0.002, 0.001, respectively), but not for small-artery occlusion and cardioembolism. Our finding showed that MMP-3 5A/6A may be a useful biomarker for predicting recurrence for LAA stroke patients and 5A allele carrier may bear a higher risk of recurrence among patients with the subtype of LAA.

Enhancement of cell growth and glycolic acid production by overexpression of membrane-bound alcohol dehydrogenase in Gluconobacter oxydans DSM 2003.

Membrane-bound alcohol dehydrogenase (mADH) was overexpressed in Gluconobacter oxydans DSM 2003, and the effects on cell growth and glycolic acid production were investigated. The transcription levels of two terminal ubiquinol oxidases (bo3 and bd) in the respiratory chain of the engineered strain G. oxydans-adhABS were up-regulated by 13.4- and 3.8-fold, respectively, which effectively enhanced the oxygen uptake rate, resulting in higher resistance to acid. The cell biomass of G. oxydans-adhABS could increase by 26%-33% when cultivated in a 7L bioreactor. The activities of other major membrane-bound dehydrogenases were also increased to some extent, particularly membrane-bound aldehyde dehydrogenase (mALDH), which is involved in the catalytic oxidation of aldehydes to the corresponding acids and was 1.26-fold higher. Relying on the advantages of the above, G. oxydans-adhABS could produce 73.3gl-1 glycolic acid after 45h of bioconversion with resting cells, with a molar yield 93.5% and a space-time yield of 1.63gl-1h-1. Glycolic acid production could be further improved by fed-batch fermentation. After 45h of culture, 113.8gl-1 glycolic acid was accumulated, with a molar yield of 92.9% and a space-time yield of 2.53gl-1h-1, which is the highest reported glycolic acid yield to date.