Transcriptomic Insights into Metabolism-Dependent Biosynthesis of Bacterial Nanocellulose.

Bacterial nanocellulose (BNC) is an attractive green-synthesized biomaterial for biomedical applications and various other applications. However, effective engineering of BNC production has been limited by our poor knowledge of the related metabolic processes. In contrast to the traditional perception that genome critically determines biosynthesis behaviors, here we discover that the glucose metabolism could also drastically affect the BNC synthesis in Gluconacetobacter hansenii. The transcriptomic profiles of two model BNC-producing strains, G. hansenii ATCC 53582 and ATCC 23769, which have highly similar genomes but drastically different BNC yields, were compared. The results show that their BNC synthesis capacities were highly related to metabolic activities such as ATP synthesis, ion transport protein assembly, and carbohydrate metabolic processes, confirming an important role of metabolism-related transcriptomes in governing the BNC yield. Our findings provide insights into the microbial biosynthesis behaviors from a transcriptome perspective, potentially guiding cellular engineering for biomaterial synthesis.

Screening, identification, and low-energy ion modified breeding of a yeast strain producing high level of 3-hydroxypropionic acid.

3-Hydroxypropionic acid (3HP) is an important platform chemical with a wide range of applications. The biological preparation of this compound is safe and low cost. In this study, orchard soil and human waste were used as raw materials to screen microbial strains that could produce 3HP in selective medium containing varying amounts of propionic acid. A yeast strain that can use propionic acid as substrate and produce 48.96 g/L 3HP was screened. Morphological observation, physiological and biochemical identification, and 26s rDNA sequencing identified the IS451 strain as Debaryomyces hansenii. The low-energy ion N+ , with the energy of 10 keV and a dose of 70 × 2.6 × 1013  ions/cm2 , was implanted into the IS451 strain. The mutant strain WT39, whose 3HP titer reached 62.42 g/L, was obtained. The strain exhibited genetic stability and tolerance to high concentrations of propionic acid and was considered to have broad application prospects.

Trends of case detection and other indicators of leprosy in China during 1985-2002.

OBJECTIVE: To analyze the trends of case detection and other indicators of leprosy in China during 1985-2002. METHODS: Data reported by each province were collected by China National Leprosy Database in Nanjing P.R. China. All data about registered cases were put into computer for analysis. RESULTS: From 1985 to 2002, a total of 49,477 new leprosy cases had been detected. Among them, 69.5% were multibacillary cases and 25.4% had grade 2 disability. The child cases aged below 15 years accounted for 3.74% of total cases. Totally, 5824 cases and 303 cases relapsed after dapsone (DDS) mono-therapy and multidrug therapy (MDT), respectively. Case detection showed a marked reduction from 0.47/100,000 in 1985 to 0.18/100,000 in 1993 although there were several spurts due to operational factors. From 1994, case detection showed no significant decline. The grade 2 disability among new patients decreased from 31.4% in 1985 to 23.4% in 2002. The child case detection rate among new cases fluctuated between 2.70%-3.56% from 1999 to 2002. The incidence of relapse declined after the introduction of DDS mono-therapy. However, it increased after the introduction of MDT. CONCLUSION: China experiences in leprosy control show that it will take a long time with continuing present leprosy control activities to bring down the case detection and other indicators to a very low level even after reaching the elimination goal of leprosy.

Studies on risk of leprosy relapses in China: relapses after treatment with dapsone monotherapy

Based upon the data from the Chinese National System for Leprosy Surveillance, this paper reports on the relapses in 297,343 leprosy patients [multibacillary (MB) 106,518, paucibacillary (PB) 190,825] cured by dapsone monotherapy. A total of 11,055 (MB 8675, PB 2380) patients relapsed during an accumulated follow-up period of 4,229,050 patient-years (PY), giving an overall relapse rate of 3.72 per 100 cases or 2.61 per 1000 PY, i.e., 8.14% or 5.91 per 1000 PY over an average follow-up period of 13.8 +/- 8.4 years in MB patients and 1.25% or 0.86 per 1000 PY over an average period of 14.5 +/- 8.9 years in PB patients. For either the overall relapse rate per 100 cases or per 1000 PY, the differences between MB and PB patients were statistically significant, except during 36-40 years of follow up. For both MB and PB patients, the relapse rates showed consistently significant decreases year by year, particularly in PB patients whose relapse rate per 1000 PY was 1.21 in year 10 of follow up; whereas it remained more than 10 per 1000 PY in MB patients. In view of that, the overall relapse rates in MB and PB patients cured by dapsone monotherapy were acceptably low, and most of these patients have been followed up for more than a mean incubation period of observed dapsone relapse. Along with the further extension of follow up, the risk of relapse in dapsone-cured patients will not be expected to increase. This conclusion should be considered when planning policy for the management of patients released from dapsone monotherapy.