Relationship between agitation speed and the morphological characteristics of Verticillium lecanii CS-625 during spore production

Verticillium lecanii is recognized as an entomopathogenic fungus, and has high potential in the biological control of pests. In this study, it was investigated that the relationship between agitation speed in a 2.5 L stirred tank reactor (STR) at 25°C and initial pH 5.5, and the morphological characteristics of V. lecanii CS-625, such as hyphal length/width, spore length/width, and the number of tips during spore production. The agitation speed affected the hyphae patterns and the number of tips. The number of spores rapidly increased at 48 to 60 h of cultivation, and the highest spore productivity (2.5 × 10¹⁰ spore/L·h at 60 h) occurred with an agitation speed of 350 rpm and an aeration rate of 1.0 vvm. The number of tips increased in proportion to the increase in spore production during the same culture time. The highest number of tips (4.8 × 10⁸ tipJ.mL) was obtained at 72 h of cultivation. The shortest mean spore length (2.8 μm) was obtained at 60 h of cultivation. Therefore, it was determined that the increased number of tips and decreased mean spore length were closely related to the production of V. lecanii spores.     

Description of <Emphasis Type="Italic">Streptomyces neopeptinius</Emphasis> sp. nov., an actinobacterium with broad spectrum antifungal activities

A streptomycete strain producing broad-spectrum antifungal substances was taxonomically characterized. The strain, designated KNF 2047(T) (= SH-09(T) = KCTC 10586BP(T)), was found to form extensively branching aerial and substrate mycelia, and produce spiny-ornamented spores with loose spiral chains. The whole cell hydrolyzates contained major amount of LL-diaminopimelic acid. The major fatty acids of the phospholipids were saturated and branched fatty acids containing 14~17 carbons, and the major isoprenoid quinones were hexa-and octa-hydrogenated menaquinones with 9 isoprene units. The phylogenetic analysis using the 16S rRNA gene indicated that the strain belongs to the genus Streptomyces but forms an independent phyletic line. These results clearly demonstrate that strain KNF2047(T) forms a new center of taxonomic variation within Streptomyces, for which the name Streptomyces neopeptinius sp. nov. is proposed.     

Acinetobacter baumannii outer membrane protein A targets the nucleus and induces cytotoxicity

Acinetobacter baumannii is an emerging opportunistic pathogen responsible for healthcare-associated infections. The outer membrane protein A of A. baumannii (AbOmpA) is the most abundant surface protein that has been associated with the apoptosis of epithelial cells through mitochondrial targeting. The nuclear translocation of AbOmpA and the subsequent pathology on host cells were further investigated. AbOmpA directly binds to eukaryotic cells. AbOmpA translocates to the nucleus by a novel monopartite nuclear localization signal (NLS). The introduction of rAbOmpA into the cells or a transient expression of AbOmpA–EGFP causes the nuclear localization of these proteins, while the fusion proteins of AbOmpAΔNLS–EGFP and AbOmpA with substitutions in residues lysine to alanine in the NLS sequences represent an exclusively cytoplasmic distribution. The nuclear translocation of AbOmpA induces cell death in vitro . Furthermore, the microinjection of rAbOmpA into the nucleus of Xenopus laevis embryos fails to develop normal embryogenesis, thus leading to embryonic death. We propose a novel pathogenic mechanism of A. baumannii regarding the nuclear targeting of the bacterial structural protein AbOmpA.     

A novel splice variant of occludin deleted in exon 9 and its role in cell apoptosis and invasion

The tight junction protein occludin participates in cell adhesion and migration and has been shown to possess antitumorigenic properties; however, the exact mechanism underlying these effects is poorly understood. In liver cell lines, we identified an occludin splice variant deleted in exon 9 (Occ(DeltaE9)). Furthermore, comparison analysis of wild-type occludin (Occ(WT)) and Occ(DeltaE9) revealed that exon 9 played important roles in the induction of mitochondria-mediated apoptosis and the inhibition of invasion, along with the downregulation of matrix metalloproteinase expression. In addition, by using the calcium indicator X-rhod-1, and the inositol trisphosphate receptor inhibitor 2-aminoethoxydiphenyl borate, we found that Occ(WT) but not Occ(DeltaE9) increased calcium release from the endoplasmic reticulum. In conclusion, our results showed that occludin mediates apoptosis and invasion by elevating the cytoplasmic calcium concentration and that exon 9 of occludin is an important region that mediates these effects.     

Strategies for systems-level metabolic engineering

Bio-based production of chemicals, fuels and materials is becoming more and more important due to the increasing environmental problems and sharply increasing oil price. To make these biobased processes economically competitive, the biotechnology industry explores new ways to improve the performance of microbial strains in fermentation processes. In contrast to the random mutagenesis and/or intuitive local metabolic engineering practiced in the past, we are now moving towards global-scale metabolic engineering, aided by various experimental and computational tools. This has recently led to some remarkable achievements for the overproduction of valueadded products. In this review, we highlight several relevant gene manipulation tools and computational tools using genome-scale stoichiometric models, and provide useful strategies for successful metabolic engineering along with selected exemplary studies.     

Expression of aquaporin 5 (AQP5) promotes tumor invasion in human non small cell lung cancer

The aquaporins (AQP) are water channel proteins playing a major role in transcellular and transepithelial water movement. Recently, the role of AQPs in human carcinogenesis has become an area of great interest. Here, by immunohistochemistry (IHC), we have found an expression of AQP5 protein in 35.3% (IHC-score: > or = 1, 144/408) of the resected NSCLC tissue samples. Cases with AQP5-positive status (IHC-score: > or = 2) displayed a higher rate of tumor recurrence than negative ones in NSCLC (54.7% vs. 35.1%, p = 0.005) and worse disease-free survival (p = 0.033; OR = 1.52; 95%CI: 1.04-2.23). Further in vitro invasion assay using BEAS-2B and NIH3T3 cells stably transfected with overexpression constructs for full length wild-type AQP5 (AQP5) and its two mutants, N185D which blocks membrane trafficking and S156A which blocks phosphorylation on Ser156, showed that AQP5 induced cell invasions while both mutants did not. In BEAS-2B cells, the expression of AQP5 caused a spindle-like and fibroblastic morphologic change and losses of cell-cell contacts and cell polarity. Only cells with AQP5, not either of two mutants, exhibited a loss of epithelial cell markers and a gain of mesenchymal cell markers. In a human SH3-domains protein array, cellular extracts from BEAS-2B with AQP5 showed a robust binding activity to SH3-domains of the c-Src, Lyn, and Grap2 C-terminal. Furthermore, in immunoprecipitation assay, activated c-Src, phosphorylated on Tyr416, showed a stronger binding activity to cellular extracts from BEAS-2B with AQP5 compared with N185D or S156A mutant. Fluorescence in situ hybridization (FISH) analysis failed to show evidence of genomic amplification, suggesting AQP5 expression as a secondary event. Based on these clinical and molecular observations, we conclude that AQP5, through its phosphorylation on Ser156 and subsequent interaction with c-Src, plays an important role in NSCLC invasion and, therefore, may provide a unique opportunity for developing a novel therapeutic target as well as a prognostic marker in NSCLC.     

ADIPOQ/adiponectin induces cytotoxic autophagy in breast cancer cells through STK11/LKB1-mediated activation of the AMPK-ULK1 axis

ADIPOQ/adiponectin, an adipocytokine secreted by adipocytes in the breast tumor microenvironment, negatively regulates cancer cell growth hence increased levels of ADIPOQ/adiponectin are associated with decreased breast cancer growth. However, its mechanisms of action remain largely elusive. We report that ADIPOQ/adiponectin induces a robust accumulation of autophagosomes, increases MAP1LC3B-II/LC3B-II and decreases SQSTM1/p62 in breast cancer cells. ADIPOQ/adiponectin-treated cells and xenografts exhibit increased expression of autophagy-related proteins. LysoTracker Red-staining and tandem-mCherry-GFP-LC3B assay show that fusion of autophagosomes and lysosomes is augmented upon ADIPOQ/adiponectin treatment. ADIPOQ/adiponectin significantly inhibits breast cancer growth and induces apoptosis both in vitro and in vivo, and these events are preceded by macroautophagy/autophagy, which is integral for ADIPOQ/adiponectin-mediated cell death. Accordingly, blunting autophagosome formation, blocking autophagosome-lysosome fusion or genetic-knockout of BECN1/Beclin1 and ATG7 effectively impedes ADIPOQ/adiponectin induced growth-inhibition and apoptosis-induction. Mechanistic studies show that ADIPOQ/adiponectin reduces intracellular ATP levels and increases PRKAA1 phosphorylation leading to ULK1 activation. AMPK-inhibition abrogates ADIPOQ/adiponectin-induced ULK1-activation, LC3B-turnover and SQSTM1/p62-degradation while AMPK-activation potentiates ADIPOQ/adiponectin's effects. Further, ADIPOQ/adiponectin-mediated AMPK-activation and autophagy-induction are regulated by upstream master-kinase STK11/LKB1, which is a key node in antitumor function of ADIPOQ/adiponectin as STK11/LKB1-knockout abrogates ADIPOQ/adiponectin-mediated inhibition of breast tumorigenesis and molecular analyses of tumors corroborate in vitro mechanistic findings. ADIPOQ/adiponectin increases the efficacy of chemotherapeutic agents. Notably, high expression of ADIPOQ receptor ADIPOR2, ADIPOQ/adiponectin and BECN1 significantly correlates with increased overall survival in chemotherapy-treated breast cancer patients. Collectively, these data uncover that ADIPOQ/adiponectin induces autophagic cell death in breast cancer and provide in vitro and in vivo evidence for the integral role of STK11/LKB1-AMPK-ULK1 axis in ADIPOQ/adiponectin-mediated cytotoxic autophagy.     

Decreased hippocampal brain‐derived neurotrophic factor and impaired cognitive function by hypoglossal nerve transection in rats

The hypoglossal nerve controls tongue movements, and damages of it result in difficulty in mastication and food intake. Mastication has been reported to maintain hippocampus‐dependent cognitive function. This study was conducted to examine the effect of tongue motor loss on the hippocampus‐dependent cognitive function and its underlying mechanism. Male Sprague Dawley rats were subjected to the initial training of Morris water maze task before or after the bilateral transection of hypoglossal nerves (Hx). When the initial training was given before the surgery, the target quadrant dwelling time during the probe test performed at a week after the surgery was significantly reduced in Hx rats relative to sham‐operated controls. When the initial training was given after the surgery, Hx affected the initial and reversal trainings and probe tests. Brain‐derived neurotrophic factor (BDNF) expression, cell numbers and long‐term potentiation (LTP) were examined in the hippocampus on the 10^th day, and BrdU and doublecortin staining on the 14^th day, after the surgery. Hx decreased the hippocampal BDNF and cells in the CA1/CA3 regions and impaired LTP. BrdU and doublecortin staining was decreased in the dentate gyrus of Hx rats. Results suggest that tongue motor loss impairs hippocampus‐dependent cognitive function, and decreased BDNF expression in the hippocampus may be implicated in its underlying molecular mechanism in relation with decreased neurogenesis/proliferation and impaired LTP.     

All‐Nanomat Lithium‐Ion Batteries: A New Cell Architecture Platform for Ultrahigh Energy Density and Mechanical Flexibility

The ongoing surge in demand for high‐energy/flexible rechargeable batteries relentlessly drives technological innovations in cell architecture as well as electrochemically active materials. Here, a new class of all‐nanomat lithium‐ion batteries (LIBs) based on 1D building element‐interweaved heteronanomat skeletons is demonstrated. Among various electrode materials, silicon (Si, for anode) and overlithiated layered oxide (OLO, for cathode) materials are chosen as model systems to explore feasibility of this new cell architecture and achieve unprecedented cell capacity. Nanomat electrodes, which are completely different from conventional slurry‐cast electrodes, are fabricated through concurrent electrospinning (for polymeric nanofibers) and electrospraying (for electrode materials/carbon nanotubes (CNTs)). Si (or rambutan‐shaped OLO/CNT composite) powders are compactly embedded in the spatially interweaved polymeric nanofiber/CNT heteromat skeletons that play a crucial role in constructing 3D‐bicontinuous ion/electron transport pathways and allow for removal of metallic foil current collectors. The nanomat Si anodes and nanomat OLO cathodes are assembled with nanomat Al₂O₃ separators, leading to the fabrication of all‐nanomat LIB full cells. Driven by the aforementioned structural/chemical uniqueness, the all‐nanomat full cell shows exceptional improvement in electrochemical performance (notably, cell‐based gravimetric energy density = 479 W h kg_Cell^?1) and also mechanical deformability, which lie far beyond those achievable with conventional LIB technologies.