Measuring Bacterial Colonization on Arabidopsis thaliana Roots in Hydroponic Condition.

Measuring bacterial colonization on Arabidopsis thaliana root is one of the most frequent experiments in plant-microbe interaction studies. A standardized method for measuring bacterial colonization in the rhizosphere is necessary to improve reproducibility. We first cultured sterile A.thaliana in hydroponic conditions and then inoculated the bacterial cells in the rhizosphere at a final concentration of OD600 of 0.01. At 2 days post-inoculation, the root tissue was harvested and washed three times in sterile water to remove the uncolonized bacterial cells. The roots were then weighed, and the bacterial cells colonized on the root were collected by vortex. The cell suspension was diluted in a gradient with a phosphate-buffered saline (PBS) buffer, followed by plating onto a Luria-Bertani (LB) agar medium. The plates were incubated at 37 °C for 10 h, and then, the single colonies on LB plates were counted and normalized to indicate the bacterial cells colonized on roots. This method is used to detect bacterial colonization in the rhizosphere in mono-interaction conditions, with good reproducibility.

[Progress in metabolic engineering of biosynthesis of 3-hydroxypropionic acid].

As an important platform compound, 3-hydroxypropionic acid (3-HP) can be used as a substrate to synthesize a variety of biological products with commercial potential. The titer of 3-HP by wild-type bacteria is low, which severely limits the large-scale application and production of 3-HP. By modifying the genes related to the metabolic pathway, engineered bacteria using cheap substrates as carbon sources are constructed, the aim of reducing production cost and increasing output is realized. In this paper, the recent progress in the synthesis of 3-HP by metabolic engineering at home and abroad is reviewed. The advantages and disadvantages of glycerol pathway, malonyl-CoA pathway and beta-alanine pathway for synthesis of 3-HP are also summarized and analyzed, and the future development of 3-HP is prospected.

Application of percutaneous balloon mitral valvuloplasty in patients of rheumatic heart disease mitral stenosis combined with tricuspid regurgitation.

BACKGROUND: Tricuspid regurgitation (TR) is frequently associated with severe mitral stenosis (MS), the importance of significant TR was often neglected. However, TR influences the outcome of patients. The aim of this study was to investigate the efficacy and safety of percutaneous balloon mitral valvuloplasty (PBMV) procedure in rheumatic heart disease patients with mitral valve (MV) stenosis and tricuspid valve regurgitation. METHODS: Two hundred and twenty patients were enrolled in this study due to rheumatic heart disease with MS combined with TR. Mitral balloon catheter made in China was used to expand MV. The following parameters were measured before and after PBMV: MV area (MVA), TR area (TRA), atrial pressure and diameter, and pulmonary artery pressure (PAP). The patients were followed for 6 months to 9 years. RESULTS: After PBMV, the MVAs increased significantly (1.7 ± 0.3 cm 2 vs. 0.9 ± 0.3 cm 2 , P < 0.01); TRA significantly decreased (6.3 ± 1.7 cm 2 vs. 14.2 ± 6.5 cm 2 , P < 0.01), right atrial area (RAA) decreased significantly (21.5 ± 4.5 cm 2 vs. 25.4 ± 4.3 cm 2 , P < 0.05), TRA/RAA (%) decreased significantly (29.3 ± 3.2% vs. 44.2 ± 3.6%, P < 0.01). TR velocity (TRV) and TR continue time (TRT) as well as TRV × TRT decreased significantly (183.4 ± 9.4 cm/s vs. 254.5 ± 10.7 cm/s, P < 0.01; 185.7 ± 13.6 ms vs. 238.6 ± 11.3 ms, P < 0.01; 34.2 ± 5.6 cm vs. 60.7 ± 8.5 cm, P < 0.01, respectively). The postoperative left atrial diameter (LAD) significantly reduced (41.3 ± 6.2 mm vs. 49.8 ± 6.8 mm, P < 0.01) and the postoperative right atrial diameter (RAD) significantly reduced (28.7 ± 5.6 mm vs. 46.5 ± 6.3 mm, P < 0.01); the postoperative left atrium pressure significantly reduced (15.6 ± 6.1 mmHg vs. 26.5 ± 6.6 mmHg, P < 0.01), the postoperative right atrial pressure decreased significantly (13.2 ± 2.4 mmHg vs. 18.5 ± 4.3 mmHg, P < 0.01). The pulmonary arterial pressure decreased significantly after PBMV (48.2 ± 10.3 mmHg vs. 60.6 ± 15.5 mmHg, P < 0.01). The symptom of chest tightness and short of breath obviously alleviated. All cases followed-up for 6 months to 9 years (average 75 ± 32 months), 2 patients with severe regurgitation died (1 case of massive cerebral infarction, and 1 case of heart failure after 6 years and 8 years, respectively), 2 cases lost access. At the end of follow-up, MVA has been reduced compared with the postoperative (1.4 ± 0.4 cm 2 vs. 1.7 ± 0.3 cm 2 , P < 0.05); LAD slightly increased compared with the postoperative (45.2 ± 5.7 mm vs. 41.4 ± 6.3 mm, P < 0.05), RAD slightly also increased compared with the postoperative (36.1 ± 6.3 mm vs. 28.6 ± 5.5 mm, P < 0.05), but did not recover to the preoperative level. TRA slightly increased compared with the postoperative, but the difference was not statistically significant (P > 0.05). The PAP and left ventricular ejection fraction appeared no statistical difference compared with the postoperative (P > 0.05), the remaining patients without serious complications. CONCLUSIONS: PBMV is a safe and effective procedure for MS combined with TR in patients of rheumatic heart disease. It can alleviate the symptoms and reduce the size of TR. It can also improve the quality-of-life and prognosis. Its recent and mid-term efficacy is certain. While its long-term efficacy remains to be observed.

Relationship between hOGG1 Ser326Cys gene polymorphism and coronary artery lesions in patients with diabetes mellitus.

To study the relationship between human 8-oxoguanine glycosylase (hOGG1) Ser326Cys gene polymorphism and coronary artery lesions in patients with diabetes mellitus, we analyzed 323 patients with diabetic mellitus, who underwent coronary angiography. Using PCR-RFLP, these patients were grouped into three genotypes: Cys/Cys (n=85), Ser/Ser (n=121), and Ser/Cys (n=117). Several clinical data, including history of diseases and biochemical indices were recorded. hOGG1 mRNA expression and 8-hydroxy deoxyguanosine (8-OHdG) were measured by RT-PCR and ELISA, respectively. The quantities and severity of coronary artery with lesions were analyzed from coronary angiography. The Gensini and SYNTAX scores were detected by the unitary criteria. The 8-OHdG levels showed statistical difference among the three genotypes (F=21.56, P<0.05). Also, 8-OHdG in Cys/Cys genotype was higher than Ser/Ser and Ser/Cys genotype (q=2.32, q=3.12, P<0.05). In terms of the expression of hOGGl mRNA, the measure of hOGGl/ß-actin showed significant difference among the three groups (F=12.56, P<0.05). On comparing two groups, hOGGl/ß-actin in Cys/Cys genotype was higher thanSer/Ser and Ser/Cys genotypes (q=2.32, q=3.12, P<0.05). Percentage of 3-vessel lesions was high in Cys/Cys genotype and percentage of 1-vessel lesions was low in Ser/Cys genotype. Gensini and SYNTAX scores and ratio of complex lesions were significantly higher in the Cys/Cys genotype than the other two genotypes (FGensini=47.16, FSYNTAX=55.12; P<0.05). hOGG1 Ser326Cys polymorphism showed correlation with coronary artery lesions in patients with diabetes mellitus, and Cys/Cys genotype may have more impact on the severity of lesions.