Medium chain carboxylic acids production from waste biomass: Current advances and perspectives

Alternative chemicals to diverse fossil-fuel-based products is urgently needed to mitigate the adverse impacts of fossil fuel depletion on human development. To this end, researchers have focused on the production of biochemical from readily available and affordable waste biomass. This is consistent with current guidelines for sustainable development and provides great advantages related to economy and environment. The search for suitable biochemical products is in progress worldwide. Therefore, this review recommends a biochemical (i.e., medium chain carboxylic acids (MCCAs)) utilizing an emerging biotechnological production platform called the chain elongation (CE) process. This work covers comprehensive introduction of the CE mechanism, functional microbes, available feedstock types and corresponding utilization strategies, major methods to enhance the performance of MCCAs production, and the challenges that need to be addressed for practical application. This work is expected to provide a thorough understanding of the CE technology, to guide and inspire researchers to solve existing problems in depth, and motivate large-scale MCCAs production.     

Global distribution and invasion pattern of oriental fruit fly,Bactrocera dorsalis (Diptera: Tephritidae)

Since the start of the 20th century, many invasive alien species (IAS) have spread rapidly around the world, causing serious threats to economies, societies and the environment. Bactrocera dorsalis (Hendel) (Diptera: Tephritidae) is an important quarantine insect species in many countries that spread around the world over the last century. This review collected information on the distribution of B. dorsalis to explore the patterns of its invasion expansion. We found B. dorsalis to be distributed in 75 countries (comprised of 124 geographical distribution regions: provinces or states) in Asia, Africa, North America, South America and Oceania up to 2017. Asia and Africa were the most represented regions, accounting for 86.3% of the total number of countries. From 1910 to 1990, B. dorsalis was only found in five countries, but in the last three decades, it has experienced a sharp increase in its rate of spread, invading 70 more countries. Global temperature anomaly has significantly positive correlation with the spread of B. dorsalis. The results of this review provide a theoretical basis for understanding and predicting the continued spread of B. dorsalis under global changes.     

Host MOV10 is induced to restrict herpes simplex virus 1 lytic infection by promoting type I interferon response

Moloney leukemia virus 10 protein (MOV10) is an interferon (IFN)-inducible RNA helicase implicated in antiviral activity against RNA viruses, yet its role in herpesvirus infection has not been investigated. After corneal inoculation of mice with herpes simplex virus 1 (HSV-1), we observed strong upregulation of both MOV10 mRNA and protein in acutely infected mouse trigeminal ganglia. MOV10 suppressed HSV-1 replication in both neuronal and non-neuronal cells, and this suppression required the N-terminus, but not C-terminal helicase domain of MOV10. MOV10 repressed expression of the viral gene ICP0 in transfected cells, but suppressed HSV-1 replication independently of ICP0. MOV10 increased expression of type I IFN in HSV-1 infected cells with little effect on IFN downstream signaling. Treating the cells with IFN-α or an inhibitor of the IFN receptor eliminated MOV10 suppression of HSV-1 replication. MOV10 enhanced IFN production stimulated by cytoplasmic RNA rather than DNA. IKKε co-immunoprecipitated with MOV10 and was required for MOV10 restriction of HSV-1 replication. Mass spectrometry identified ICP27 as a viral protein interacting with MOV10. Co-immunoprecipitation results suggested that this interaction depended on the RGG box of ICP27 and both termini of MOV10. Overexpressed ICP27, but not its RGG-Box deletion mutant, rendered MOV10 unable to regulate HSV-1 replication and type I IFN production. In summary, MOV10 is induced to restrict HSV-1 lytic infection by promoting the type I IFN response through an IKKε-mediated RNA sensing pathway, and its activity is potentially antagonized by ICP27 in an RGG box dependent manner.     

Targeting ASCT2-mediated glutamine metabolism inhibits proliferation and promotes apoptosis of pancreatic cancer cells

Some tumor cells have a high rate of glutamine uptake and exhibit glutamine addiction. Alanine-serine cysteine-preferring transporter 2 (ASCT2) is a major mediator of glutamine supply in many tumor cells, but the underlying effects and mechanisms of ASCT2 in pancreatic cancer (PC) are largely unknown. Our results show that ASCT2 expression is significantly higher in PC than in normal pancreatic duct cells and pancreas. Utilizing the Kaplan–Meier Plotter database, a high expression of SLC1A5 mRNA was significantly associated with poor overall survival (OS) in patients with PC. shRNA-mediated inhibition of ASCT2 function in vitro can significantly decrease glutamine consumption, α-ketoglutarate (α-KG) production and ATP generation and increase the reactive oxygen species (ROS) level. Moreover, the antioxidant N-acetylcysteine partially attenuated the increase in the ROS levels and reduced ATP generation. These data suggest that ASCT2 mediates glutamine metabolism and maintains redox homeostasis in PC. To further investigate whether ASCT2 is involved in PC cell growth, we blocked ASCT2 activity with the ASCT2 inhibitor l-γ-glutamyl-p-nitroanilide (GPNA) and silenced the expression of ASCT2 with specific shRNAs. We found that the growth of PC cells was significantly inhibited. Additionally, knockdown of ASCT2 induced apoptosis through the Akt/mTOR signaling pathway. Furthermore, the loss of ASCT2 in BxPC-3 cell xenografts significantly inhibited tumor growth in vivo, and this effect was associated with an increase in cleaved caspase-3 expression and a decrease in Ki67 staining. Taken together, our results show that ASCT2 may be utilized as a putative therapeutic target for PC.     

Development of intramolecularly quenched fluorescent peptides as substrates of angiotensin-converting enzyme 2

Angiotensin-converting enzyme 2 (ACE2 or ACEH) is a novel angiotensin-converting enzyme-related carboxypeptidase that cleaves a single amino acid from angiotensin I, des-Arg bradykinin, and many other bioactive peptides. Using des-Arg bradykinin as a template, we designed a series of intramolecularly quenched fluorogenic peptide substrates for ACE2. The general structure of the substrates was F-X-Q, in which F was the fluorescent group, Abz, Q was the quenching group (either Phe(NO(2)) or Tyr(NO(2))), and X was the intervening peptide. These substrates were selectively cleaved by recombinant human ACE2, as shown by MS and HPLC. Quenching efficiency increased as the peptide sequence was shortened from 8 to 3 aa, and also when Tyr(NO(2)) was used as a quenching group instead of Phe(NO(2)). Two of the optimized substrates, TBC5180 and TBC5182, produced a signal:noise ratio of better than 20 when hydrolyzed by ACE2. Kinetic measurements with ACE2 were as follows: TBC5180, K(m)=58 microM and k(cat)/K(m)=1.3x10(5)M(-1)s(-1); TBC5182, K(m)=23 microM and k(cat)/K(m)=3.5 x 10(4)M(-1)s(-1). Thus, based on hydrolysis rate, TBC5180 was a better substrate than TBC5182. However, TBC5180 was also hydrolyzed by ACE, whereas TBC5182 was not cleaved, suggesting that TBC5182 was a selective for ACE2. We conclude that these two peptides can be used as fluorescent substrates for high-throughput screening for selective inhibitors of ACE2 enzyme.     

幽门螺旋杆菌感染的慢性胃炎胃窦粘膜内NF-κB和TGF-α表达及其意义

目的　探讨幽门螺旋杆菌 (Hp)与慢性胃炎患者胃窦粘膜内NF κB和TGF α表达之间的关系。方法　用免疫细胞化学方法 ,检测Hp+ 和Hp-胃炎患者及正常人的胃窦部活检标本。结果　NF κB和TGF α在正常组胃粘膜内弱表达。在胃炎病人 ,NF κB和TGF α表达增强。特别是在Hp+ 组 ,NF κB和TGF α呈高表达 ,与Hp-组和正常组比较均有显著性差异 (P <0 0 5和P <0 0 1)。此外在G细胞和部分腺上皮的细胞核内也呈高表达。TGF α常以颗粒状的特征位于腺上皮细胞核上区而且高表达。结论　NF κB和TGF α的表达在胃炎组增强 ,而且Hp+ 组远高于其他两组。NF κB和TGF α二者的表达平行且成呈正相关。