Enhanced submerged Aspergillus ficuum phytase production by implementation of fed-batch fermentation

Phytase is an important feed and food additive, which is both used in animal and human diets. Phytase has been used to increase the absorption of several divalent ions, amino acids, and proteins in the bodies and to decrease the excessive phosphorus release in the manure to prevent negative effects on the environment. To date, microbial phytase has been mostly produced in solid-state fermentations with insignificant production volumes. There are only a few studies in the literature that phytase productions were performed in submerged bench-top reactor scale. In our previous studies, growth parameters (temperature, pH, and aeration) and important fermentation medium ingredients (glucose, Na-phytate, and CaSO₄) were optimized. This study was undertaken for further enhancement of phytase production with Aspergillus ficuum in bench-top bioreactors by conducting fed-batch fermentations. The results showed that addition of 60 g of glucose and 10 g of Na-phytate at 96 h of fermentation increased phytase activity to 3.84 and 4.82 U/ml, respectively. Therefore, the maximum phytase activity was further enhanced with addition of glucose and Na-phytate by 11 and 40 %, respectively, as compared to batch phytase fermentations. It was also reported that phytase activity increased higher in early log stage additions than late log stage additions because of higher microbial activity. In addition, the phytase activity in fed-batch fermentation did not drop significantly as compared to the batch fermentation. Overall, this study shows that fungal phytase can be successfully produced in submerged fed-batch fermentations.     

A Rare Duplication on Chromosome 16p11.2 Is Identified in Patients with Psychosis in Alzheimer's Disease

Epidemiological and genetic studies suggest that schizophrenia and autism may share genetic links. Besides common single nucleotide polymorphisms, recent data suggest that some rare copy number variants (CNVs) are risk factors for both disorders. Because we have previously found that schizophrenia and psychosis in Alzheimer''s disease (AD+P) share some genetic risk, we investigated whether CNVs reported in schizophrenia and autism are also linked to AD+P. We searched for CNVs associated with AD+P in 7 recurrent CNV regions that have been previously identified across autism and schizophrenia, using the Illumina HumanOmni1-Quad BeadChip. A chromosome 16p11.2 duplication CNV (chr16: 29,554,843-30,105,652) was identified in 2 of 440 AD+P subjects, but not in 136 AD subjects without psychosis, or in 593 AD subjects with intermediate psychosis status, or in 855 non-AD individuals. The frequency of this duplication CNV in AD+P (0.46%) was similar to that reported previously in schizophrenia (0.46%). This duplication CNV was further validated using the NanoString nCounter CNV Custom CodeSets. The 16p11.2 duplication has been associated with developmental delay, intellectual disability, behavioral problems, autism, schizophrenia (SCZ), and bipolar disorder. These two AD+P patients had no personal of, nor any identified family history of, SCZ, bipolar disorder and autism. To the best of our knowledge, our case report is the first suggestion that 16p11.2 duplication is also linked to AD+P. Although rare, this CNV may have an important role in the development of psychosis.     

Enhanced production ofd(−)-lactic acid by mutants ofLactobacillus delbrueckii ATCC 9649

Summary Chemical mutagenesis with ethyl methanesulfonate (EMS) was used to develop strains ofLactobacillus delbrueckii (ATCC 9649) that tolerated increased lactic acid concentrations while continuously producing the acid. Three mutants (DP2, DP3 and DP4) were compared with wild-typeL. delbrueckii by standing fermentations with different glucose concentrations. All three mutants produced higher levels of lactic acid than the wild-type. In pH-controlled (pH 6.0) stirred-tank-batch fermentations, mutant DP3 in 12% glucose, 1% yeast extract/mineral salt/oleic acid medium produced lactic acid at a rate that was more than 2-times faster than the wild-type. Mutant DP3 also produced 77 g/l lactic acid compared with 58 g/l for the wild-type. Overall, compated with wild-type, the mutants DP2 and DP3 exhibited faster specific growth rates, shorter lag phases, greater lactic acid yields, tolerated higher lactic acid concentrations, and produced as much as 12% lactic acid in 12% glucose, 3% yeast extract/mineral salt/oleic acid medium which required an additional 9% glucose when the residual glucose concentration decreased to 3%. Mutant DP3 was stable for over 1.5 years (stored freeze dried). The strain development procedure was very successful; mutants with enhanced lactic acid-producing capacity were obtained each time the procedure was employed.Journal Paper No. J-14087 of the Iowa Agriculture and Home Economics Experiment Station, Ames, IA. Projects No. 2889 and 0178.     

Enhanced production of bacterial cellulose by using a biofilm reactor and its material property analysis

Bacterial cellulose has been used in the food industry for applications such as low-calorie desserts, salads, and fabricated foods. It has also been used in the paper manufacturing industry to enhance paper strength, the electronics industry in acoustic diaphragms for audio speakers, the pharmaceutical industry as filtration membranes, and in the medical field as wound dressing and artificial skin material. In this study, different types of plastic composite support (PCS) were implemented separately within a fermentation medium in order to enhance bacterial cellulose (BC) production by Acetobacter xylinum. The optimal composition of nutritious compounds in PCS was chosen based on the amount of BC produced. The selected PCS was implemented within a bioreactor to examine the effects on BC production in a batch fermentation. The produced BC was analyzed using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), thermogravimetric analysis (TGA), and dynamic mechanical analysis (DMA). Among thirteen types of PCS, the type SFYR+ was selected as solid support for BC production by A. xylinum in a batch biofilm reactor due to its high nitrogen content, moderate nitrogen leaching rate, and sufficient biomass attached on PCS. The PCS biofilm reactor yielded BC production (7.05 g/L) that was 2.5-fold greater than the control (2.82 g/L). The XRD results indicated that the PCS-grown BC exhibited higher crystallinity (93%) and similar crystal size (5.2 nm) to the control. FESEM results showed the attachment of A. xylinum on PCS, producing an interweaving BC product. TGA results demonstrated that PCS-grown BC had about 95% water retention ability, which was lower than BC produced within suspended-cell reactor. PCS-grown BC also exhibited higher T _max compared to the control. Finally, DMA results showed that BC from the PCS biofilm reactor increased its mechanical property values, i.e., stress at break and Young's modulus when compared to the control BC. The results clearly demonstrated that implementation of PCS within agitated fermentation enhanced BC production and improved its mechanical properties and thermal stability.     

Short-term hyperglycemia increases endothelial glycocalyx permeability and acutely decreases lineal density of capillaries with flowing red blood cells.

Hyperglycemia is becoming recognized as an important risk factor for microvascular dysfunction. We hypothesized that short-term hyperglycemia, either on the scale of hours or weeks, alters the barrier function and the volume of the endothelial glycocalyx and decreases functional capillary density and deformability of the red blood cells (RBCs). All experiments were performed in anesthetized, mechanically ventilated, C57BL/6 mice that were either normoglycemic, acutely hyperglycemic (25 mM) for 60 min due to infusion of glucose, or hyperglycemic (25 mM) for 2-4 wk (db/db mice). The glycocalyx was probed using 40-kDa Texas red dextran, which is known to permeate the glycocalyx, and 70-kDa FITC dextran, which has impaired access to the glycocalyx in healthy animals. Clearance of the dye from the blood was measured. An orthogonal polarization spectral imaging technique was used to visualize the number of capillaries with flowing RBCs of the dorsal flexor muscle. The data indicate that short-term hyperglycemia causes a rapid decrease of the ability of the glycocalyx to exclude 70-kDa dextran. No change in the vascular permeation of 40-kDa dextran was observed. Glycocalyx volume was not affected by short-term hyperglycemia. In addition, 1 h of hyperglycemia resulted in a 38% decrease of the lineal density of capillaries with flowing RBCs. This decreased lineal density was not observed in the 2- to 4-wk hyperglycemia model. Short-term hyperglycemia was without any effect on the deformablity of the RBCs. The data indicate that the described increased vascular permeability with hyperglycemia can be ascribed to an increased permeability of the glycocalyx, identifying the glycocalyx as a potential early target of hyperglycemia.     

A very simple high‐performance liquid chromatographic method with fluorescence detection for the determination of gemifloxacin in human breast milk

A high‐performance liquid chromatographic method with fluorescence detection was developed and validated for the determination of gemifloxacin in human breast milk. The proposed method allows the determination of gemifloxacin in breast milk samples without complex sample preparation. The samples were mixed with a mobile phase and filtered with a 0.45 µm polytetrafluoroethylene filter before analysis. Chromatographic separation was carried out on a C18 column (150 × 4.6 mm, 5 µm I.D.) using methanol:50 mM ortho‐phosphoric acid solution (40:60) as the mobile phase with a 1.0 mL/min flow rate. Quantitation was performed using fluorescence detection with an excitation wavelength at 272 nm and an emission wavelength at 395 nm. The linear range was found to be 0.1–2.5 µg/mL. The method was applied successfully for the determination of gemifloxacin in breast milk obtained from a breastfeeding mother after oral administration of a single tablet that included 320 mg gemifloxacin per gemifloxacin tablet. Copyright © 2015 John Wiley & Sons, Ltd.     

Culturable bacterial microbiota of Plagiodera versicolora (L.) (Coleoptera: Chrysomelidae) and virulence of the isolated strains

Plagiodera versicolora (Laicharting, 1781) (Coleoptera: Chrysomelidae) is an important forest pest which damages many trees such as willow, poplar, and hazelnut. In order to find new microbes that can be utilized as a possible microbial control agent against this pest, we investigated the culturable bacterial flora of it and tested the isolated bacteria against P. versicolora larvae and adults. We were able to isolate nine bacteria from larvae and adults. The isolates were characterized using a combination of morphological, biochemical, and physiological methods. Additionally, we sequenced the partial sequence of the 16S rRNA gene to verify conventional identification results. Based on characterization studies, the isolates were identified as Staphylococcus sp. Pv1, Rahnella sp. Pv2, Rahnella sp. Pv3, Rahnella sp. Pv4, Rahnella sp. Pv5, Pantoea agglomerans Pv6, Staphylococcus sp. Pv7, Micrococcus luteus Pv8, and Rahnella sp. Pv9. The highest insecticidal activity against larvae and adults was obtained from M. luteus Pv8 with 50 and 40 % mortalities within 10 days after treatment, respectively. Extracellular enzyme activity of the bacterial isolates such as amylase, proteinase, lipase, cellulose, and chitinase was also determined. Consequently, our results show that M. luteus Pv8 might be a good candidate as a possible microbial control agent against P. versicolora and were discussed with respect to biocontrol potential of the bacterial isolates.     

CD36 as a target to prevent cardiac lipotoxicity and insulin resistance

The fatty acid transporter and scavenger receptor CD36 is increasingly being implicated in the pathogenesis of insulin resistance and its progression towards type 2 diabetes and associated cardiovascular complications. The redistribution of CD36 from intracellular stores to the plasma membrane is one of the earliest changes occurring in the heart during diet induced obesity and insulin resistance. This elicits an increased rate of fatty acid uptake and enhanced incorporation into triacylglycerol stores and lipid intermediates to subsequently interfere with insulin-induced GLUT4 recruitment (i.e., insulin resistance). In the present paper we discuss the potential of CD36 to serve as a target to rectify abnormal myocardial fatty acid uptake rates in cardiac lipotoxic diseases. Two approaches are described: (i) immunochemical inhibition of CD36 present at the sarcolemma and (ii) interference with the subcellular recycling of CD36. Using in vitro model systems of high-fat diet induced insulin resistance, the results indicate the feasibility of using CD36 as a target for adaptation of cardiac metabolic substrate utilization. In conclusion, CD36 deserves further attention as a promising therapeutic target to redirect fatty acid fluxes in the body.     

Brassinosteroids Modify Yield,Quality, and Antioxidant Components in Grapes (Vitis vinifera cv. Alphonse Lavallée)

Brassinosteroids (BRs) are a class of polyhydroxysteroids that have been recognized as a “sixth class of plant hormones.” Exogenous application of BRs affects a broad spectrum of physiological responses, secondary metabolite accumulation, and resistance against stress factors in plants. In this study, the effects of pre-harvest 24-epibrassinolide (24-eBL) applications on the accumulation of antioxidant compound, yield, and quality properties of Alphonse Lavallée grape cultivar were examined. 24-eBL was applied to vines with 13 combinations including different application times and concentrations of 24-eBL (0.2, 0.4, 0.6, and 0.8 mg L⁻¹) and control. It was found that 24-eBL increased yield, quality, and antioxidant compounds in grapes when it was applied at appropriate concentration and application time. The concentration 0.2 mg L⁻¹ of 24-eBL applied to vines at three times (7 days after berry set + veraison + 30 days after veraison) was the most suitable application providing the highest yield and some quality properties such as cluster weight, berry weight, and specific gravity. Concentrations 0.6 and 0.8 mg L⁻¹ of 24-eBL applied at veraison to vines can be suggested for total phenolics, β-carotene, ascorbic acid, and trans-resveratrol accumulation for Alphonse Lavallée as a practical application, while the application consists of 0.6 mg L⁻¹ of 24-eBL and 7 days after berry set + veraison + 30 days after veraison seems to be the best treatment for anthocyanin content.