A Two-Year Surveillance of 2009 Pandemic Influenza A (H1N1) in Guangzhou, China: From Pandemic to Seasonal Influenza?

In this two-years surveillance of 2009 pandemic influenza A (H1N1) (pH1N1) in Guangzhou, China, we reported here that the scale and duration of pH1N1 outbreaks, severe disease and fatality rates of pH1N1 patients were significantly lower or shorter in the second epidemic year (May 2010-April 2011) than those in the first epidemic year (May 2009-April 2010) (P<0.05), but similar to those of seasonal influenza (P>0.05). Similar to seasonal influenza, pre-existing chronic pulmonary diseases was a risk factor associated with fatal cases of pH1N1 influenza. Different from seasonal influenza, which occurred in spring/summer seasons annually, pH1N1 influenza mainly occurred in autumn/winter seasons in the first epidemic year, but prolonged to winter/spring season in the second epidemic year. The information suggests a tendency that the epidemics of pH1N1 influenza may probably further shift to spring/summer seasons and become a predominant subtype of seasonal influenza in coming years in Guangzhou, China

Multi-chaotic Sparrow Search Algorithm Based on Learning Mechanism

To solve the shortcomings of sparrow search algorithm (SSA), such as falling into local extremum easily influenced by initial solution and slow convergence in late iteration, a multi-chaotic sparrow search algorithm&nbsp; based on learning mechanism (MMCSSA) is proposed. Firstly, the centroid opposition-based learning strategy (COBL) is introduced to generate elite population to enhance the exploration of multi-source high-quality search areas, and then the local extreme escape ability and convergence performance of the algorithm are improved. Secondly, a scaled golden sine algorithm is proposed and embedded in SSA to improve the guidance search mode and enhance the global search ability of the algorithm. Thirdly, a multi-chaos mapping strategy based on learning mechanism is proposed, which utilizes the characteristics of multi-chaos and multi-disturbance, and enforces different disturb-ance features on the algorithm by dynamically calling different chaotic maps. When chaotic perturbation fails, Gaussian mutation strategy is introduced to deeply develop the current solution. The two strategies cooperate and promote each other, greatly enhancing the ability of the algorithm to escape from local optimal. Finally, the proposed algorithm is applied to 12 benchmark functions with different characteristics, and the results show that compared with other algorithms, MMCSSA has better performance in convergence accuracy, optimization speed and robustness

Promoter Screening from Bacillus subtilis in Various Conditions Hunting for Synthetic Biology and Industrial Applications.

The use of Bacillus subtilis in synthetic biology and metabolic engineering is highly desirable to take advantage of the unique metabolic pathways present in this organism. To do this, an evaluation of B. subtilis' intrinsic biological parts is required to determine the best strategies to accurately regulate metabolic circuits and expression of target proteins. The strengths of promoter candidates were evaluated by measuring relative fluorescence units of a green fluorescent protein reporter, integrated into B. subtilis' chromosome. A total of 84 predicted promoter sequences located upstream of different classes of proteins including heat shock proteins, cell-envelope proteins, and proteins resistant against toxic metals (based on similarity) and other kinds of genes were tested. The expression levels measured ranged from 0.0023 to 4.53-fold of the activity of the well-characterized strong promoter P43. No significant shifts were observed when strains, carrying different promoter candidates, were cultured at high temperature or in media with ethanol, but some strains showed increased activity when cultured under high osmotic pressure. Randomly selected promoter candidates were tested and found to activate transcription of thermostable β-galactosidase (bgaB) at a similar level, implying the ability of these sequences to function as promoter elements in multiple genetic contexts. In addition, selected promoters elevated the final production of both cytoplasmic bgaB and secreted protein α-amylase to about fourfold and twofold, respectively. The generated data allows a deeper understanding of B. subtilis' metabolism and will facilitate future work to develop this organism for synthetic biology