Production of alkaline pectinase: a case study investigating the use of tobacco stalk with the newly isolated strain Bacillus tequilensis CAS-MEI-2-33.

BACKGROUND: Tobacco stalk (TS), a major agricultural waste abundant in pectin, has resulted in concerns about the need for its reuse. The nicotine in TS is considered a chemical that is to\xic and hazardous to the environment. RESULTS: In this study, Bacillus tequilensis CAS-MEI-2-33 was isolated from cigar wrappers to produce alkaline pectinase using TS. Subsequently, the medium and fermentation conditions for the production of pectinase by B. tequilensis CAS-MEI-2-33 were optimized. The optimal fermentation period, pH of the initial fermentation medium, concentration of TS, and inoculum amount for B. tequilensis CAS-MEI-2-33 were 40 h, 40 g/L, 7.0, and 3%, respectively. Under optimal conditions, the pectinase activity was 1370 U/mL. Then, the enzymatic properties, such as the optimum pH, reaction temperature, temperature stability, and effects of metal ions, were studied. The optimal pH was determined to be 10.0, indicating that the enzyme was an alkaline pectinase. The optimal temperature was 40 °C, and pectinase activity was stable at 40 °C. The Ag+ metal ions were shown to remarkably promote enzyme activity. The pectinase was partly purified by ammonium sulfate precipitation, ion exchange chromatography, and Sephacryl S-100 chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and LC-MS/MS analyses were utilized to analyze the pectinase. CONCLUSIONS: This study provided a new alkaline pectinase candidate and a new strategy for the use of TS.

The Arabidopsis Calcium-Dependent Protein Kinases (CDPKs) and Their Roles in Plant Growth Regulation and Abiotic Stress Responses.

As a ubiquitous secondary messenger in plant signaling systems, calcium ions (Ca2+) play essential roles in plant growth and development. Within the cellular signaling network, the accurate decoding of diverse Ca2+ signal is a fundamental molecular event. Calcium-dependent protein kinases (CDPKs), identified commonly in plants, are a kind of vital regulatory protein deciphering calcium signals triggered by various developmental and environmental stimuli. This review chiefly introduces Ca2+ distribution in plant cells, the classification of Arabidopsis thaliana CDPKs (AtCDPKs), the identification of the Ca2+-AtCDPK signal transduction mechanism and AtCDPKs' functions involved in plant growth regulation and abiotic stress responses. The review presents a comprehensive overview of AtCDPKs and may contribute to the research of CDPKs in other plants.

Genome Sequence of Staphylococcus aureus PX03, an Acetoin-Producing Strain with a Small-Sized Genome.

Staphylococcus aureus PX03 can produce acetoin efficiently. Here, we present a 2.38-Mb assembly of its genome sequence, which might provide further insights into the molecular mechanism of its acetoin biosynthesis to further improve its biotechnological applications.

Prevalence and risk factors of organ failure in patients with severe acute pancreatitis.

BACKGROUND: This study was undertaken to determine the prevalence of organ failure and its risk factors in patients with severe acute pancreatitis (SAP). METHODS: A retrospective analysis was made of 186 patients with SAP who were had been hospitalized in the intensive care unit of Jinzhong First People's Hospital between March 2000 and October 2009. The patients met the diagnostic criteria of SAP set by the Surgical Society of the Chinese Medical Association in 2006. The variables collected included age, gender, etiology of SAP, the number of comorbidit, APACHEII score, contrast-enhanced CT (CECT) pancreatic necrosis, CT severity index (CTSI) , abdominal compartment syndrome (ACS) , the number of organ failure, and the number of death. The prevalence and mortality of organ failure were calculated. The variables were analyzed by unconditional multivariate logistic regression to determine the independent risk factors for organ failure in SAP. RESULTS: Of 186 patients, 96 had organ failure. In the 96 patients, 47 died. There was a significant association among the prevalence of organ failure and age, the number of comorbidity, APACHEII score, CECT pancreatic necrosis, CTSI, and ACS. An increase in age, the number of comorbidity, APACHEII score, CECT pancreatic necrosis were correlated with increased number of organ failure. Age, the number of comorbidity, APACHEII score, CECT pancreatic necrosis, CTSI and ACS were assessed by unconditional multivariate logistic regression. CONCLUSIONS: Organ failure occurred in 51.6% of the 186 patients with SAP. The mortality of SAP with organ failure was 49.0%. Age, the number of comorbidity, APACHEII score, CECT pancreatic necrosis, CTSI and ACS are independent risk factors of organ failure.