Production of Mannitol from a High Concentration of Glucose by Candida parapsilosis SK26.001

A novel strain, SK26.001, which can produce mannitol from a high concentration of glucose without the addition of fructose, was isolated from sugarcane juice. This strain was identified as Candida parapsilosis based on 18S ribosomal RNA (rRNA) sequence analysis and the morphological and physiological-biochemical characteristics of the strain. Under optimized fermentation conditions, the mannitol concentration in shake flasks reached 68.5 g/L. When batch fermentation was performed, the fed glucose was completely consumed after 72 h, resulting in a final mannitol concentration of 80.3 g/L. Fed-batch fermentation was then performed with glucose feed. During the fed-batch process, ammonia water was added to maintain the pH at 4.0. The mannitol concentration in the fermenter reached 97.1 g/L after 120 h, with a total glucose consumption of 284 g/L.

Clinical and genetic analyses of Chinese patients with Gitelman syndrome

To evaluate the genotype-phenotype relationship of Gitelman syndrome in Chinese patients. We selected patients with Gitelman syndrome presenting hypokalemia. Medical history, clinical manifestations, laboratory test results, and imaging data of these patients were collected for analysis. Target gene sequencing was performed to evaluate the genotype-phenotype relationship. Gitelman syndrome was diagnosed based on medical history, clinical manifestations, laboratory test results, and imaging data. The causative gene for Gitelman syndrome, SLC12A3, and the causative gene for the classic Bartter syndrome, CLCNKB, were screened for disease-causing mutations by direct sequencing. Clinical diagnoses of ten patients were consistent with Gitelman syndrome. Disease-causing mutations in the SLC12A3 gene were found in six patients. Among the variants, T60M in exon 1 was the hot spot in Chinese patients. Additionally, we found a small deletion of ACGG in exon 3 and L671P in exon 16; these have not been reported in previous studies. No disease-causing mutations were observed in the other four patients. Since mutations in the SLC12A3 and CLCNKB genes are not present in all patients with clinical manifestations of Gitelman syndrome, genetic screening after clinical diagnosis is essential.

[Improved clinical outcome of acute myeloid leukemia with FLT3-ITD mutation treated with sorafenib]

OBJECTIVE

To analyze the efficacy of sorafenib on the treatment of patients diagnosed as acute myeloid leukemia(AML) with FLT3-ITD mutation.

METHODS

From January 2012 to February 2015, 42 cases of AML with FLT3-ITD mutation according to MICM (morphology, immunology, cytogenetics and molecular) diagnosis system in our hospital were retrospectively analyzed. Thirty-two cases were refractory to chemotherapy or relapsed, who were treated with sorafenib or combined with chemotherapy. Ten patients relapsed after allogeneic hematopoietic stem cell transplantation (allo-HSCT), who were retreated with sorafenib or combined with donor lymphocyte infusion (DLI) or chemotherapy. In the first group, 13 of 32 patients accepted allo-HSCT.

RESULTS

The overall response rate of all 42 patients was 73.8%, including 4 (9.5%) complete molecular remission (CMR), 9 (21.4%) complete remission (CR), 8 (19%) complete remission with incomplete hematologic recovery (CRi), 10 (23.8%) partial remission (PR), and 11 (26.2%) none remission (NR). The response rate of sorafenib alone for 17 patients was 70.6%, and that of sorafenib plus chemotherapy was 66.7% (P=0.555). Thirteen patients who received allo-HSCT included 6 CMR/CR/CRi, 4 PR, and 3 NR before transplant. The 2-year overall survival (OS) rate and progress free survival (PFS) rate in all patients were 36.9% and 28.7%, and the corresponding median time were 18 months and 9 months respectively. The 2-year OS rate in 23 patients who received sorafenib combined with allo-HSCT was superior to that in 19 patients not receiving allo-HSCT (45.5% vs 23.9%, P=0.041), so was PFS rate (44.0% vs 9.7%, P=0.014). Twelve cases died of disease progression, four of infection, and one of chronic graft versus host disease after transplant.

CONCLUSIONS

Sorafenib combined with chemotherapy improves response rate of AML patients with FLT3-ITD mutation. Those who are treated with sorafenib plus allo-HSCT obtain better long-term survival.

Slowly digestible starch--a review

The link between carbohydrate intake and health is becoming increasingly important for consumers, particularly in the areas of glycemic index (GI) and extended energy-releasing starches. From a physiological point of view, slowly digestible starch (SDS) delivers a slow and sustained release of blood glucose along with the benefits resulting from low glycemic and insulinemic response. SDS has been implicated in several health problems, including diabetes, obesity, and cardiovascular diseases (metabolic syndromes). It may also have commercial potential as a novel functional ingredient in a variety of fields, such as nutrition, medicine, and agriculture. The present review assesses this form of digestion by analyzing methods to prepare and evaluate SDS, and factors affecting its transformation, its health benefits, and its applications.

The osteogenic potential of ligament fibroblasts is greater in ankylosing spondylitis patients than in patients with osteoarthritis

BACKGROUND

The goal of the present study was to investigate the osteogenic potential of ligament fibroblasts from patients with ankylosing spondylitis (AS).

MATERIALS AND METHODS

Ligament fibroblasts were isolated from tissues harvested from AS patients and patients with aseptic necrosis of the femoral head (ANFH) who had undergone total hip arthroplasty (THA). Cells were cultured in osteogenic induction medium (OIM) with or without bone morphogenetic protein 2 (BMP-2) for 30 days. During this time, the levels of alkaline phosphatase (ALP) and osteocalcin (OC) were determined as markers of osteogenesis.

RESULTS

Ligament fibroblasts isolated from patients with AS exhibited significantly greater potential for differentiation than those isolated from patients with osteoarthritis (ANFH).

CONCLUSION

These findings illuminate osteogenesis as a new pathway for studying the mechanism underlying ankylosis in AS patients. Factors which cause localized stromal remodeling at the enthesis significantly influence formation of new bone and further research is required to determine the mechanisms responsible for the osteogenic potential of enthesis cells and ligament fibroblasts in AS patients.

Intracellular synthesis of glutamic acid in Bacillus methylotrophicus SK19.001, a glutamate-independent poly(γ-glutamic acid)-producing strain

BACKGROUND

Bacillus methylotrophicus SK19.001 is a glutamate-independent strain that produces poly(γ-glutamic acid) (γ-PGA), a polymer of D- and L-glutamic acids that possesses applications in food, the environment, agriculture, etc. This study was undertaken to explore the synthetic pathway of intracellular L- and D-glutamic acid in SK19.001 by investigating the effects of tricarboxylic acid cycle intermediates and different amino acids as metabolic precursors on the production of γ-PGA and analyzing the activities of the enzymes involved in the synthesis of L- and D-glutamate.

RESULTS

Tricarboxylic acid cycle intermediates and amino acids could participate in the synthesis of γ-PGA via independent pathways in SK19.001. L-Aspartate aminotransferase, L-glutaminase and L-glutamate synthase were the enzymatic sources of L-glutamate. Glutamate racemase was responsible for the formation of D-glutamate for the synthesis of γ-PGA, and the synthetase had stereoselectivity for glutamate substrate.

CONCLUSION

The enzymatic sources of L-glutamate were investigated for the first time in the glutamate-independent γ-PGA-producing strain, and multiple enzymatic sources of L-glutamate were verified in SK19.001, which will benefit efforts to improve production of γ-PGA with metabolic engineering strategies.

Improving the catalytic behavior of inulin fructotransferase under high hydrostatic pressure

BACKGROUND

The demand for difructose anhydride III (DFA III), a novel functional sweetener, is growing continuously. It is produced from inulin by inulin fructotransferase (IFTase). In this study, high hydrostatic pressure (HHP), as a clean technology, was first applied to further improve the catalytic efficiency of IFTase in the process.

RESULTS

The maximum activity of IFTase was obtained under 200 MPa at 60 °C. Meanwhile, HHP lowered the energy barrier necessary for the enzymatic reaction and decreased the volume between the reactants and the transition state. Under this condition, the optimal pH for the enzymatic reaction shifted from 5.5 to 6.0. The activity was further enhanced by 65.2% in the presence of 1.5 mol L(-1) NaCl.

CONCLUSION

The catalytic reaction of IFTase was performed under HHP for the first time. HHP, as a promising green technology for bioconversion, significantly accelerated the enzymatic reaction under the appropriate operational conditions.

Polysaccharide Modification through Green Technology: Role of Endodextranase in Improving the Physicochemical Properties of (1→3)(1→6)-α-D-Glucan

The structure and properties of bioengineered (1→3)(1→6)-α-D-glucan subjected to endodextranase treatment were investigated. Upon enzyme treatment, OD220 and Mw decreased substantially during the first 60 min and thereafter slowed as the modification progressed. Compared to the native glucan, the modified sample solution had a lighter opalescent, bluish-white color. The morphological analysis revealed that bioengineered glucan produced quite a few small particles after hydrolysis. The molecular weight distribution curve gradually shifted to the low Mw region with a significant broadening distribution, and the chain hydrolysis reaction followed a combination of zeroth- and first-order processes. The NMR results showed some specific α-1,6 linkages of glucan chains were cleaved with enzyme treatment. The viscosity of modified glucan solution was markedly reduced, and the Newtonian plateaus were also observed at high shear rates (10-100 1/s). The above results suggested that the modified (1→3)(1→6)-α-D-glucan showed a tailor-made solution character similar to that of arabic gum and would be used as a novel food gum substitute in the design of artificial carbohydrate-based foods.