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2'-Fucosyllactose (2-FL), one of the most abundant oligosaccharides in human milk, has been spotlighted for its neutraceutical and pharmaceutical potentials. Microbial production of 2-FL is promising since it is efficient as compared to other production methods. In 2-FL microbial production via the salvage pathway for biosynthesis of guanosine 5'-diphosphate (GDP)-l-fucose from fucose, the conversion yield from fucose is important because of the high price of fucose. In this study, deletion of the genes (araA and rhaA) coding for arabinose isomerase (AraA) and rhamnose isomerase (RhaA) was attempted in engineered Escherichia coli for improving 2-FL production by using fucose, lactose, and glycerol. The engineered E. coli constructed previously is able to express fucokinase/GDP-l-fucose pyrophosphorylase (Fkp) from Bacteroides fragilis and the α-1,2-fucosyltransferase (FucT2) from Helicobacter pylori and deficient in β-galactosidase (LacZ), fucose isomerase (FucI), and fuculose kinase (FucK). The additional double-deletion of the araA and rhaA genes in the engineered E. coli enhanced the product yield of 2-FL to 0.52 mole 2-FL/mole fucose, and hence the concentration of 2-FL reached to 47.0 g/L, which are 44% and two-fold higher than those (23.1 g/L and 0.36 mole 2-FL/mole fucose) of the control strain in fed-batch fermentation. Elimination of sugar isomerases exhibiting promiscuous activities with fucose might be critical in the microbial production of 2-FL through the salvage pathway of GDP-l-fucose.

L-Fucose (6-deoxy-L-galactose) is a major constituent of glycans and glycolipids in mammals. Fucosylation of glycans can confer unique functional properties and may be an economical way to manufacture L-fucose. Research can extract L-fucose directly from brown algae, or by enzymatic hydrolysis of L-fucose-rich microbial exopolysaccharides. However, these L-fucose production methods are not economical or scalable for various applications. We engineered an Escherichia coli strain to produce L-fucose. Specifically, we modified the strain genome to eliminate endogenous L-fucose and lactose metabolism, produce 2'-fucosyllactose (2'-FL), and to liberate L-fucose from 2'-FL. This E. coli strain produced 16.7 g/L of L-fucose with productivity of 0.1 g·L-1 ·h-1 in a fed-batch fermentation. This study presents an efficient one-pot biosynthesis strategy to produce a monomeric form of L-fucose by microbial fermentation, making large-scale industrial production of L-fucose feasible.

A self-homodyne coherent detection technique using gain-saturated SOA (GS-SOA) is proposed. In the proposed system, local oscillator (LO) for optical coherent detection is extracted from the optical signal which is sent from the transmitter using the fact that the modulated downlink data can be erased with SOA operation in saturation region. Therefore, carrier frequency offset noise does not occur because LO light which is extracted from the received optical signal has totally same wavelength with the optical signal. In order to operate SOA operates in deep saturation region, high optical input power is needed. The proposed scheme was experimentally demonstrated, and the feasibility was discussed with the experimental results. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:561–565, 2016

Whole-cell biotransformation of fatty acids can be influenced by the activities of catalytic enzymes and by the efficiency of substrate transport into host cells. Here, we improved fatty acid hydration activity of the recombinant Escherichia coli expressing an oleate hydratase of Stenotrophomonas maltophilia by targeting the catalytic enzyme into the periplasm instead of the cytoplasm. Recombinant E. coli producing OhyA in the periplasm under guidance of the PelB signal sequence (E. coli OhyA_PP) exhibited significantly greater hydration activity with oleic acid and linoleic acid compared to a recombinant E. coli producing OhyA in the cytoplasm (E. coli OhyA_CS). For example, the oleate double bond hydration rate of E. coli OhyA_PP was >400 μmol/g dry cells/min (400 U/g dry cells), which is >10-fold higher than that of E. coli OhyA_CS. As the specific activities of the enzymes targeted into the cytoplasm and periplasm were comparable, we assumed that targeting OhyA into the periplasm could accelerate fatty acid transport to the catalytic enzymes by skipping the major mass transport barrier of the cytoplasmic membrane. Our results will contribute to the development of whole-cell biocatalysts for fatty acid biotransformation.

We propose a scalable support WDM-based orthogonal frequency division multiple access-passive optical network uplink transmission system using an injection-locked Fabry–Perot laser diode (IL-FP-LD). This system uses an injection-locking technique to enhance the usable bandwidth by making stable channel states. By properly controlling the IL-FP-LD operation, the number of optical network units (ONU) within a wavelength can be increased, which improves the optical bandwidth efficiency for the uplink transmission. The experimental results show an enhanced modulation bandwidth of 3.5 GHz. Compared with a conventional RSOA which has a modulation bandwidth of 1.5 GHz, our scheme improves the number of ONUs that can be accommodated within a wavelength more than two times. The total discrete multitone signal received from the ONUs, with QPSK mapping on the subcarriers was 6.77 Gbps over a 23-km standard single mode fiber transmission. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1727–1732, 2015

In orthogonal frequency division multiple access-passive optical network (OFDMA-PON) uplink transmission with a direct detection system, the optical beat interference (OBI) noise is a very critical issue in regard to channel performance degradation. We have proposed a novel technique to suppress the OBI noise in intensity modulation and direct detection OFDMA-PON links by using an optical spectrum broadening method using the RF-clipping tone to improve the SNR of the discrete multitone modulation (DMT) signal with OBI noise suppression. We also experimentally analyzed the dependency of the RF clipping tone on the OBI noise suppression and dither effect. The results show that the received DMT signal in the optical line terminal can achieve 3 Gb/s over a 23 km SSMF with a BER of 2.3×10−4. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2706–2711, 2014

Obese women have an increased risk for post-menopausal breast cancer. The physiological mechanism by which obesity contributes to breast tumourigenesis is not understood. We previously showed that HCCR-1 oncogene contributes to breast tumourigenesis as a negative regulator of p53 and detection of HCCR-1 serological level was useful for the diagnosis of breast cancer(.) In this study, we found that the HCCR-1 level is elevated in breast cancer tissues and cell lines compared to normal breast tissues. We identified apolipoprotein E (ApoE) interacting with HCCR-1. Our data show that HCCR-1 inhibits anti-proliferative effect of ApoE, which was mediated by diminishing ApoE secretion of breast cancer cells. Finally, HCCR-1 induced the severe obesity in transgenic mice. Those obese mice showed severe hyperlipidaemia. In conclusion, our results suggest that HCCR-1 might play a role in the breast tumourigenesis while the overexpression of HCCR-1 induces the obesity probably by inhibiting the cholesterol-lowering effect of ApoE. Therefore, HCCR-1 seems to provide the molecular link between the obesity and the breast cancer risk.