L-Alanine has important applications in food, pharmaceutical and veterinary and is used as a substrate for production of engineered thermoplastics. Microbial fermentation could reduce the production cost and promote the application of L-alanine. However, the presence of L-alanine significantly inhibit cell growth rate and cause a decrease in the ultimate L-alanine productivity. For efficient L-alanine production, a thermo-regulated genetic switch was designed to dynamically control the expression of L-alanine dehydrogenase (alaD) from Geobacillus stearothermophilus on the Escherichia coli B0016-060BC chromosome. The optimal cultivation conditions for the genetically switched alanine production using B0016-060BC were the following: an aerobic growth phase at 33 °C with a 1-h thermo-induction at 42 °C followed by an oxygen-limited phase at 42 °C. In a bioreactor experiment using the scaled-up conditions optimized in a shake flask, B0016-060BC accumulated 50.3 g biomass/100 g glucose during the aerobic growth phase and 96 g alanine/100 g glucose during the oxygen-limited phase, respectively. The L-alanine titer reached 120.8 g/l with higher overall and oxygen-limited volumetric productivities of 3.09 and 4.18 g/l h, respectively, using glucose as the sole carbon source. Efficient cell growth and L-alanine production were reached separately, by switching cultivation temperature. The results revealed the application of a thermo-regulated strategy for heterologous metabolic production and pointed to strategies for improving L-alanine production.
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http://dx.doi.org/10.1007/s12010-015-1874-x | DOI Listing |
Zhonghua Yu Fang Yi Xue Za Zhi
December 2024
Department of Clinical Laboratory Medicine, People's Hospital of Ningxia Hui Autonomous Region, Ningxia Medical University, Yinchuan750002, China.
In order to investigate the clinical manifestations and laboratory findings associated with brucellosis for the purpose of facilitating prompt clinical diagnosis and effective treatment, as well as to offer a laboratory reference for the prevention of brucellosis outbreaks. In this study, a retrospective cohort design was employed to gather epidemiological characteristics, clinical symptoms, and associated laboratory data from 391 patients diagnosed with bacterial culture-positive brucellosis at the People's Hospital of Ningxia Hui Autonomous Region between 2019 and 2023. The patients were categorized into four age groups, with each group representing a 20 years age interval.
View Article and Find Full Text PDFEur Radiol
December 2024
Department of Radiology, The Affiliated Hospital of Qingdao University, Qingdao, China.
Objective: To develop and compare machine learning models based on CT morphology features, serum biomarkers, and basic physical conditions to predict esophageal variceal bleeding.
Materials And Methods: Two hundred twenty-four cirrhotic patients with esophageal variceal bleeding and non-bleeding were included in the retrospective study. Clinical and serum biomarkers were used in our study.
Zhonghua Wei Zhong Bing Ji Jiu Yi Xue
November 2024
Department of Emergency, Kweichow Moutai Hospital, Zunyi 564500, Guizhou, China. Corresponding author: Zhou Manhong, Email:
Objective: To investigate the protective effect and possible mechanism of sulforaphane (SFN) on acute liver injury in mice induced by diquat (DQ) poisoning.
Methods: Forty-eight male C57BL/6 mice were divided into Control group, DQ model group (DQ group), SFN intervention group (DQ+SFN group), and SFN control group (SFN group) using a random number table method, with 12 mice in each group. Acute liver injury mice model was established by one-time intraperitoneal injection of 1 mL of 40 mg/kg DQ solution at once.
Acta Vet Scand
December 2024
Department of Veterinary Hygiene and Management, Faculty of Veterinary Medicine, Cairo University, Giza, 12211, Egypt.
Background: Rearing poultry under stressful high stocking density (HSD) conditions is a common commercial practice to increase profitability, despite its negative effects on broiler physiology and welfare. Many feed additives are used to alleviate the negative impact of such practices. This study investigated the ameliorative effects of guanidinoacetic acid (GAA) on growth performance, ingestive behavior, immune response, antioxidant status, stress indicators, and intestinal histomorphometry of broilers subjected to HSD.
View Article and Find Full Text PDFLipids Health Dis
December 2024
Division of Gastroenterology, Affiliated RenHe Hospital of Three Gorges University, Yichang, 443001, China.
Background/aims: Research has indicated that treatment with rosuvastatin can improve liver pathology in metabolic-associated fatty liver disease (MAFLD) patients and that treatment with Bifidobacterium can improve MAFLD. Therefore, the effects of Bifidobacterium, rosuvastatin, and their combination on related indices in a rat model of diet-induced MAFLD need to be investigated.
Methods: Forty rats were divided into five groups: the normal diet group (N), high-fat diet (HFD) model group (M), HFD + probiotic group (P), HFD + statin group (S), and HFD + probiotic + statin group (P-S).
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