Formation of Concentrated Nanoemulsion by W/O Microemulsion Dilution Method: Biodiesel, Tween 80, and Water System

In this work, we show the formation of concentrated green O/W nanoemulsion (dispersed phase mass fraction was up to 0.5) by diluting W/O microemulsion in the water/Tween 80/biodiesel system. The mechanism of the formation of nanoemulsions was examined and illustrated by small-angle X-ray scattering (SAXS) and cryogenic transmission electron microscopy (cryo-TEM). At high temperature, nanosized droplets formed spontaneously due to the surfactant migration and inversion upon dilution of W/O microemulsions, but these droplets were highly unstable. When cooled to room temperature, their stability was highly enhanced due to the decrease of collision frequency rate and the enhancement of stabilization of the oil/water interface. Even though, the Ostwald ripening still results in growth of droplets of the nanoemulsions after long-term storage, which limits the practical applications of nanoemulsions. W/O microemulsions are thermodynamic systems. Hence, W/O microemulsions that can form nanoemulsions by simple dilution of water can be used as an alternative to O/W nanoemulsion during storage and transport. Furthermore, biodiesel nanoemulsions could meet the requirements of green chemistry and engineering and be used as new green lubricants in water-based drilling fluid

Engineering Escherichia coli for Highly Efficient Biosynthesis of Lacto‑<i>N</i>‑difucohexaose II through De Novo GDP‑l‑fucose Pathway

Lacto-N-difucohexaose II (LNDFH II) is a typical fucosylated human milk oligosaccharide and can be enzymatically produced from lacto-N-tetraose (LNT) by a specific α1,3/4-fucosyltransferase from Helicobacter pylori DMS 6709, referred to as FucT14. Previously, we constructed an engineered Escherichia coli BL21(DE3) with a single plasmid for highly efficient biosynthesis of LNT. In this study, two additional plasmids harboring the de novo GDP-L-fucose pathway module and FucT14, respectively, were further introduced to construct the strain for successful biosynthesis of LNDFH II. FucT14 was actively expressed, and the engineered strain produced LNDFH II as the major product, lacto-N-fucopentaose (LNFP) V as the minor product, and a trace amount of LNFP II and 3-fucosyllactose as very minor products. Additional expression of the α1,3-fucosyltransferase FutM1 from a Bacteroidaceae bacterium from the gut metagenome could obviously enhance the LNDFH II biosynthesis. After optimization of induction conditions, the maximum titer reached 3.011 g/L by shake-flask cultivation. During the fed-batch cultivation, LNDFH II was highly efficiently produced with the highest titer of 18.062 g/L and the productivity yield of 0.301 g/L·h

Ca²⁺ Ion Responsive Pickering Emulsions Stabilized by PSSMA Nanoaggregates

A novel Ca²⁺ ion responsive particulate emulsifier, which is based on copolymer nanoaggregates, is reported in this work. Results from dynamic light scattering (DLS) and cryo-transmission electron microscopy (cryo-TEM) indicate that the formation of poly (4-styrenesulfonic acid-<i>co</i>-maleic acid) sodium salt (PSSMA) nanoaggregates is strongly dependent on Ca²⁺ concentration. The PSSMA copolymer only aggregates above a critical Ca²⁺ concentration (0.2 M) with an average diameter of 10–40 nm. After dilution with water, PSSMA nanoaggregates are rapidly redissolved again. On the basis of the properties of PSSMA nanoaggregates, Ca²⁺ ion responsive Pickering emulsions were successfully prepared. At high Ca²⁺ concentrations, the emulsions with high stability against coalescence can be prepared with the size in the submicrometer range as determined by DLS. Cryo-TEM and dynamic interfacial tension results confirm the adsorption of PSSMA nanoaggregates at the interface, which is the key to the stability of the emulsions. More importantly, rapid demulsification can be achieved by dilution with water on demand. It is because, upon dilution with water, PSSMA nanoaggregates undergo a transition from stable nanoaggregates to individual polymer chains, which leads to interfacial desorption of nanoaggregates and rapid demulsification of emulsions. Thus, this finding presents a new manipulation on emulsion stability and is expected to provide a useful guidance in the fields of oil recovery, food science, environment protection, and so on

Proposed model for Acm/Dacm and 5′-O-sulfonamide group biosynthesis.

<p>A) Biosynthetic pathway of ascamycin/dealanylascamycin. B) Biosynthetic pathway for 5′-O-sulfonamide group formation.</p

Deduced ORFs and their predicted functions in the ascamycin/dealanylascamycin gene cluster.

<p>Deduced ORFs and their predicted functions in the ascamycin/dealanylascamycin gene cluster.</p

Characterization of Biosynthetic Genes of Ascamycin/Dealanylascamycin Featuring a 5′-O-Sulfonamide Moiety in <i>Streptomyces sp.</i> JCM9888

<div><p>Ascamycin (ACM) and dealanylascamycin (DACM) are nucleoside antibiotics elaborated by <i>Streptomyces sp</i>. JCM9888. The later shows broad spectrum inhibition activity to various gram-positive and gram-negative bacteria, eukaryotic <i>Trypanosoma</i> and is also toxic to mice, while ascamycin is active against very limited microorganisms, such as <i>Xanthomonas</i>. Both compounds share an unusual 5′-<i>O</i>-sulfonamide moiety which is attached to an adenosine nucleoside. In this paper, we first report on the 30 kb gene cluster (23 genes, <i>acmA</i> to <i>acmW</i>) involved in the biosynthesis of these two antibiotics and a biosynthetic assembly line was proposed. Of them, six genes (AcmABGKIW) are hypothetical genes involved in 5′-O-sulfonamide formation. Two flavin adenine dinucleotide (FAD)-dependent chlorinase genes <i>acmX</i> and <i>acmY</i> were characterized which are significantly remote from <i>acmA-W</i> and postulated to be required for adenine C2-halogenation. Notably gene disruption of <i>acmE</i> resulted in a mutant which could only produce dealanylascamycin but was blocked in its ability to biosynthesize ascamycin, revealing its key role of conversion of dealanylascamycin to ascamycin.</p></div

Gene organization of ascamycin/dealanylascamycin biosynthesis pathway.

<p>A) AcmA to AcmW. B) Chlorinases <i>acmX</i> and <i>acmY</i>.</p

Chemical structures of nucleoside antibiotics in this study: dealanylascamycin 1, ascamycin 2, nucleocidin 3.

<p>Chemical structures of nucleoside antibiotics in this study: dealanylascamycin 1, ascamycin 2, nucleocidin 3.</p

Additional file 4: of A cytoplasmic long noncoding RNA LINC00470 as a new AKT activator to mediate glioblastoma cell autophagy

The expression of PI3K in GBM cells. The expression of PI3K was measured by Western blotting in GBM cells. (DOCX 204 kb

Additional file 1 of Characterization of a wheat stable QTL for spike length and its genetic effects on yield-related traits

Supplementary Material