Acetyl-CoA is a fundamental metabolite for all life on Earth, and is also a key starting point for the biosynthesis of a variety of industrial chemicals and natural products. Here we design and construct a Synthetic Acetyl-CoA (SACA) pathway by repurposing glycolaldehyde synthase and acetyl-phosphate synthase. First, we design and engineer glycolaldehyde synthase to improve catalytic activity more than 70-fold, to condense two molecules of formaldehyde into one glycolaldehyde. Second, we repurpose a phosphoketolase to convert glycolaldehyde into acetyl-phosphate. We demonstrated the feasibility of the SACA pathway in vitro, achieving a carbon yield ~50%, and confirmed the SACA pathway by 13C-labeled metabolites. Finally, the SACA pathway was verified by cell growth using glycolaldehyde, formaldehyde and methanol as supplemental carbon source. The SACA pathway is proved to be the shortest, ATP-independent, carbon-conserving and oxygen-insensitive pathway for acetyl-CoA biosynthesis, opening possibilities for producing acetyl-CoA-derived chemicals from one-carbon resources in the future.

Polysaccharides are ubiquitous biomolecules found in nature that contain various biological and pharmacological activities that are employed in functional foods and therapeutic agents. Natural polysaccharides are obtained mainly by extraction and purification, which may serve as reliable procedures to enhance the quality and the yield of polysaccharide products. Moreover, structural analysis of polysaccharides proves to be promising and crucial for elucidating structure–activity relationships. Therefore, this report summarizes the recent developments and applications in extraction, separation, purification, and structural analysis of polysaccharides of plants and fungi.

BackgroundCritically ill patients with 2009 H1N1 influenza are often treated in intensive care units (ICUs), representing significant risk of nosocomial transmission to critical care clinicians and other patients. Despite a large body of literature and guidelines recommending infection control practices, numerous barriers have been identified in ICUs, leading to poor compliance to the use of personal protective equipment (PPE). The use of PPE among critical care clinicians has not been extensively evaluated, especially during the pandemic influenza. This study examined the knowledge, attitudes, and self-reported behaviors, and barriers to compliance with the use of PPE among ICU healthcare workers (HCWs) during the pandemic influenza.Methodology/Principal FindingsA survey instrument consisting of 36 questions was developed and mailed to all HCWs in 21 ICUs in 17 provinces in China. A total of 733 physicians, nurses, and other professionals were surveyed, and 650 (88.7%) were included in the analysis. Fifty-six percent of respondents reported having received training program of pandemic influenza before they cared for H1N1 patients, while 77% reported to have adequate knowledge of self and patient protection. Only 18% of respondents were able to correctly identify all components of PPE, and 55% reported high compliance (>80%) with PPE use during patient care. In multivariate analysis, vaccination for 2009 H1N1 influenza, positive attitudes towards PPE use, organizational factors such as availability of PPE in ICU, and patient information of influenza precautions, as well as reprimand for noncompliance by the supervisors were associated with high compliance, whereas negative attitudes towards PPE use and violation of PPE use were independent predictors of low compliance.Conclusion/SignificanceKnowledge and self-reported compliance to recommended PPE use among Chinese critical care clinicians is suboptimal. The perceived barriers should be addressed in order to close the significant gap between perception and knowledge or behavior.