Icariin alleviates oxygen-induced retinopathy by targeting microglia hexokinase 2.

Retinopathy of prematurity (ROP) is a retinal disease-causing retinal neovascularization that can lead to blindness. Oxygen-induced retinopathy (OIR) is a widely used ROP animal model. Icariin (ICA) has anti-oxidative and anti-inflammation properties; however, whether ICA has a regulatory effect on OIR remains unclear. In this study, ICA alleviated pathological neovascularization, microglial activation and blood-retina barrier (BRB) damage in vivo. Further results indicated that endothelial cell tube formation, migration and proliferation were restored by ICA treatment in vitro. Proteomic microarrays and molecular mimicry revealed that ICA can directly bind to hexokinase 2 (HK2) and decrease HK2 protein expression in vivo and in vitro. In addition, ICA inhibited the AKT/mTOR/HIF1α pathway activation. The effects of ICA on pathological neovascularization, microglial activation and BRB damage disappeared after HK2 overexpression in vivo. Similarly, the endothelial cell function was revised after HK2 overexpression. HK2 overexpression reversed ICA-induced AKT/mTOR/HIF1α pathway inhibition in vivo and in vitro. Therefore, ICA prevented pathological angiogenesis in OIR in an HK2-dependent manner, implicating ICA as a potential therapeutic agent for ROP.

iPSC-based model of Vogt-Koyanagi-Harada disease for phenotype recapitulation and drug screening.

Vogt-Koyanagi-Harada (VKH) disease, a major blinding eye disease, is characterized by an autoimmune response against melanocytes in multiple organs throughout the body. Currently, the aetiology and pathogenesis of VKH disease are unclear, and the treatment strategy needs to be further optimized. The retinal pigment epithelium (RPE), a monolayer of pigmented cells of the fundus, is essential for maintaining normal visual function and is involved in both the acute and chronic stages of VKH disease. Therefore, the functions of the RPE may play a critical role in the aetiology and treatment of VKH disease. Herein, we established a human induced pluripotent stem cell (hiPSC) RPE model of VKH disease by reprogramming peripheral blood mononuclear cells (PBMCs) into iPSCs and then differentiating them into RPE cells. Patient-derived RPE cells exhibited barrier disruption, impaired phagocytosis, and depigmentation compared with those from normal controls, which was consistent with the features of VKH disease. Furthermore, a small molecular compound targeting EGR2 was found to rescue the barrier and phagocytic functions of the hiPSC-RPE cells through high-throughput virtual screening and functional studies, suggesting a promising strategy for the treatment of VKH disease.

Screening and identification of miR-181a-5p in oral squamous cell carcinoma and functional verification in vivo and in vitro.

BACKGROUND: Oral squamous cell carcinoma (OSCC) is a common malignant tumor associated with poor prognosis. MicroRNAs (miRNAs) play crucial regulatory roles in the cancer development. However, the role of miRNAs in OSCC development and progression is not well understood. METHODS: We sought to establish a dynamic Chinese hamster OSCC animal model, construct miRNA differential expression profiles of its occurrence and development, predict its targets, and perform functional analysis and validation in vitro. RESULTS: Using expression and functional analyses, the key candidate miRNA (miR-181a-5p) was selected for further functional research, and the expression of miR-181a-5p in OSCC tissues and cell lines was detected. Subsequently, transfection technology and a nude mouse tumorigenic model were used to explore potential molecular mechanisms. miR-181a-5p was significantly downregulated in human OSCC specimens and cell lines, and decreased miR-181a-5p expression was observed in multiple stages of the Chinese hamster OSCC animal model. Moreover, upregulated miR-181a-5p significantly inhibited OSCC cell proliferation, colony formation, invasion, and migration; blocked the cell cycle; and promoted apoptosis. BCL2 was identified as a target of miR-181a-5p. BCL2 may interact with apoptosis- (BAX), invasion- and migration- (TIMP1, MMP2, and MMP9), and cell cycle-related genes (KI67, E2F1, CYCLIND1, and CDK6) to further regulate biological behavior. Tumor xenograft analysis indicated that tumor growth was significantly inhibited in the high miR-181a-5p expression group. CONCLUSION: Our findings indicate that miR-181a-5p can be used as a potential biomarker and provide a novel animal model for mechanistic research on oral cancer.

Increased METTL3 expression and m6A RNA methylation may contribute to the development of dry eye in primary Sjögren's syndrome.

BACKGROUND: Primary Sjögren's syndrome (pSS) is a chronic autoimmune disorder defined by xerostomia and keratoconjunctivitis sicca, and its etiology remains unknown. N6-methyladenosine (m6A) is the predominant posttranscriptional modification in eukaryotic mRNAs and is dynamically regulated by m6A regulators. Dysregulation of m6A modification is closely associated with several autoimmune disorders, but the role of m6A modification in pSS remains unknown. This study investigated the potential role of m6A and m6A-related regulators in pSS patients with dry eye. METHODS: This cross-sectional study included forty-eight pSS patients with dry eye and forty healthy controls (HCs). Peripheral blood mononuclear cells (PBMCs) were isolated, and the level of m6A in total RNA was measured. The expression of m6A regulators was determined utilizing real-time PCR and western blotting. The serological indicators detected included autoantibodies, immunoglobulins (Igs), complement factors (Cs), and inflammatory indicators. Dry eye symptoms and signs were measured, including the ocular surface disease index, Schirmer's test (ST), corneal fluorescein staining score (CFS), and tear break-up time. Spearman's correlation coefficient was employed to assess the associations of m6A and m6A-related regulator expression with clinical characteristics. RESULTS: The expression level of m6A was markedly increased in the PBMCs of pSS patients with dry eye compared to HCs (P value<0.001). The relative mRNA and protein expression levels of the m6A regulators methyltransferase-like 3 (METTL3) and YT521-B homology domains 1 were markedly elevated in pSS patients with dry eye (both P value<0.01). The m6A RNA level was found to be positively related to METTL3 expression in pSS patients (r = 0.793, P value<0.001). Both the m6A RNA level and METTL3 mRNA expression correlated with the anti-SSB antibody, IgG, ST, and CFS (all P values < 0.05). The m6A RNA level was associated with C4 (r = -0.432, P value = 0.002), while METTL3 mRNA expression was associated with C3 (r = -0.313, P value = 0.030). CONCLUSIONS: Our work revealed that the upregulation of m6A and METTL3 was associated with the performance of serological indicators and dry eye signs in pSS patients with dry eye. METTL3 may contribute to the pathogenesis of dry eye related to pSS.

ThhspA1 is involved in lacA transcriptional regulation of Trametes hirsuta AH28-2 exposed to o-toluidine.

White rot fungi, especially Trametes spp., respond to a wide range of aromatic compounds and dramatically enhance laccase activity, while the activation mechanisms remain to be elucidated. Here, we show that an Hsp70 homolog named ThhspA1 regulates the transcription of laccase LacA in Trametes hirsuta AH28-2 when confronted with o-toluidine. ThhspA1 is pulled down by lacA promoter sequence from the nuclear mixture extracted from T. hirsuta AH28-2 induced by 2 mM o-toluidine. Silencing of ThhspA1 results in a sharp decrease in lacA transcripts and laccase activity in vivo. By comparison, ThhspA1 overexpression does not affect lacA transcription, and laccase activity shows slight enhancement or remains unchanged upon induction with o-toluidine. Electrophoretic mobility shift assays suggest a direct interaction between ThhspA1 and the lacA promoter region. Further investigation shows that the integrity of ThhspA1 is critical since its substrate binding domain (SBD) and nucleotide-binding domain (NBD) are both necessary for DNA binding, with a higher affinity of SBD than NBD based on fluorescence polarization assay. Our results demonstrate that ThhspA1 functions as an aromatic-stress-related DNA binding transcriptional factor required for LacA expression.

miR-450b promotes cell migration and invasion by inhibiting SERPINB2 in oral squamous cell carcinoma.

OBJECTIVE: microRNA-450b (miR-450b) plays an important role in cancer progression; however, its function in oral squamous cell carcinoma (OSCC) remains largely unknown. This study aimed to investigate the action mechanisms of miR-450b in OSCC. MATERIALS AND METHODS: OSCC animal model was established via continuous induction with single-drug 7, 12-dimethylbenzo[a]anthracene (DMBA). Animal tissue samples were pathologically typed using haematoxylin-eosin (HE) staining. The Cancer Genome Atlas (TCGA) database was used to predict miR-450b and SERPINB2 expression in head and neck squamous cell carcinoma (HNSCC). qRT-PCR and Western blotting were used to detect gene and protein expression in OSCC tissue and cells, respectively. OSCC cell proliferation, growth, migration and invasion were detected using CCK-8, colony formation, transwell migration and matrigel invasion assays, respectively. Bioinformatic tools were used to predict miR-450b target genes. Dual-luciferase reporter assay was used to verify targeting between miR-450b and SERPINB2. Finally, small interfering RNA (siRNA) was used to reduce SERPINB2 expression to detect its effect on tumourigenesis. RESULTS: Four stages of OSCC carcinogenesis (normal oral epithelium, simple epithelial hyperplasia, dysplasia and OSCC) were identified. miR-450b was found to be overexpressed in OSCC animal samples, HNSCC samples and human OSCC cells. Upregulation of miR-450b significantly promoted OSCC cell proliferation, colony formation, migration and invasion, while its downregulation had the opposite effect. SERPINB2 was found to be a miR-450b target gene, and its expression was negatively correlated with miR-450b expression. Altering SERPINB2 expression effectively inhibited OSCC cell invasion, metastasis and epithelial-mesenchymal transition (EMT). CONCLUSIONS: miR-450b plays a key role in OSCC tumourigenesis by regulating OSCC cell migration, invasion and EMT via SERPINB2.

DNA and RNA editing without sequence limitation using the flap endonuclease 1 guided by hairpin DNA probes.

Here, we characterized a flap endonuclease 1 (FEN1) plus hairpin DNA probe (hpDNA) system, designated the HpSGN system, for both DNA and RNA editing without sequence limitation. The compact size of the HpSGN system make it an ideal candidate for in vivo delivery applications. In vitro biochemical studies showed that the HpSGN system required less nuclease to cleave ssDNA substrates than the SGN system we reported previously by a factor of ∼40. Also, we proved that the HpSGN system can efficiently cleave different RNA targets in vitro. The HpSGN system cleaved genomic DNA at an efficiency of ∼40% and ∼20% in bacterial and human cells, respectively, and knocked down specific mRNAs in human cells at a level of ∼25%. Furthermore, the HpSGN system was sensitive to the single base mismatch at the position next to the hairpin both in vitro and in vivo. Collectively, this study demonstrated the potential of developing the HpSGN system as a small, effective, and specific editing tool for manipulating both DNA and RNA without sequence limitation.

Intravenous Recombinant Tissue-Type Plasminogen Activator Thrombolysis for Acute Central Retinal Artery Occlusion.

INTRODUCTION: Central retinal artery occlusion (CRAO), an ocular stroke, causes severe and permanent visual impairment. Thrombolytic therapy is currently the main treatment option for CRAO. Intravenous thrombolysis with recombinant tissue-type plasminogen activator (rt-PA) has been extensively applied in the treatment of CRAO with the proven advantages of effectiveness and safety. This meta-analysis aimed to assess the efficacy of intravenous rt-PA thrombolysis for the management of CRAO by evaluating the pooled evidence. METHODS: A comprehensive literature search of electronic databases including PubMed, OVID, and Cochrane Library was conducted up to and including March 2019. All studies reporting visual outcomes after CRAO with thrombolytic therapy were collected. Data on visual acuity and adverse events were recorded and assessed in this analysis. Data were inputted into the statistical software of STATA. The studies were weighed by the inverse of the variance and merged in a random-effects model. RESULTS: The systematic review process yielded 7 eligible studies including 121 patients with CRAO who received the intravenous rt-PA treatment. Sixty-two patients showed improvement in visual acuity (52.0%; 95% CI, 34.0%-70.0%) following rt-PA intravenous thrombolytic therapy. The observed improvement rate in the intravenous rt-PA treatment group was significantly higher than the conservative treatment group (40.4% vs. 13.0%; OR = 5.16; 95% CI, 1.90-14.05). The incidence rate of complications was relatively low (11 out of the 121 patients). Hemorrhage (9/11) was the major reported complication. Mortality was zero. DISCUSSION: This meta-analysis indicated that intravenous rt-PA thrombolysis could be an effective and safe strategy for the management of CRAO. However, a more detailed large-scale clinical trial is warranted to strengthen the evidence-based therapeutic guidance.

Animal model and bioinformatics analyses suggest the TIMP1/MMP9 axis as a potential biomarker in oral squamous cell carcinoma.

Oral squamous cell carcinoma (OSCC) is a common malignant tumor of the head and neck. However, the molecular mechanism underlying its development and progression is yet unclear. Genes that are differentially expressed, that is, differentially expressed genes (DEGs), between normal and diseased tissues are believed to be involved in disease development and progression. To identify the DEGs in OSCC and explore their role in occurrence and progression, we established a Chinese hamster OSCC model, determined the DEG, screened the identified DEGs, and performed Gene Ontology (GO) and KEGG enrichment analyses. A protein-protein interaction (PPI) network was generated to screen potential candidate genes. We then analyzed the expression, tumor stage and prognosis of candidate genes using the Gene Expression Profiling Interactive Analysis (GEPIA) database. Finally, we verified the candidate DEGs by quantitative real-time PCR and Gene Expression Omnibus analysis. The results showed 194 significantly DEGs, 140 enriched GO terms, and 8 KEGG pathways, which suggested that OSCC was closely related to the immune system, cell migration, and extracellular matrix. GEPIA and PPI network analysis revealed that SPP1, TNC, and ACTA1 were significantly related to tumor staging; SPP1, tissue inhibitors of matrix metallopeptidases (MMPs) 1 (TIMP1), and ACTA1 were closely related to prognosis. The scores for the top five highest degree genes were close, and the TIMP1/MMP9 axis appeared to be at the center of the PPI network, indicating that expression changes in the TIMP1/MMP9 axis and related genes may be involved in tumor invasion and metastasis. These findings provide novel insights into the mechanism of oral cancer.

An unusual GH1 ß-glucosidase from marine sediment with ß-galactosidase and transglycosidation activities for superior galacto-oligosaccharide synthesis.

A novel ß-glucosidase, BglD1 with high ß-galactosidase and transglycosidation activities, was screened and cloned from the deep-sea bacterium Bacillus sp. D1. BglD1 exhibited the maximal ß-glucosidase and ß-galactosidase activities at 55-60 °C and pH 5.5-6.0. The enzyme maintained approximately 50% of its original activity at 35 °C and pH 6.0 after 120-h incubation. When applied to synthesize galacto-oligosaccharides (GOS), BglD1 generated 118.3 g/L GOS (33.8% (w/w)) from 350 g/L lactose, with trisaccharide Gal-ß(1 → 3)-Lac and disaccharide Gal-ß(1 → 4)-Gal as the main components. Furthermore, BglD1 could hydrolyze lactose in milk and produce GOS simultaneously. Using milk as the substrate, BglD1 hydrolyzed 88.5% lactose and produced 3.3 g/L GOS after incubation at 30 °C for 1 h. To improve the transglycosidation activity, a mutant BglD1:E224T was generated based on the semi-rational design. The GOS yield of BglD1:E224T was 11.5% higher than that of BglD1 when using lactose solution as the substrate. Thus, BglD1 and the mutant could be used as beneficial alternatives of the existing ß-galactosidases for the production of GOS.

Improving the thermostability of a GH97 dextran glucosidase by rational design.

This study was aimed at improving the thermostability of dextran glucosidase PspAG97A, a member of the glycoside hydrolase family 97, from Pseudoalteromonas sp. K8. A total of 9 lysine residues were chosen using the TKSA-MC program based on the optimization of surface charge-charge interactions and were mutated to glutamate for shifting the enzyme's isoelectric point off its optimum pH value. Three mutants K75E, K363E and K420E showed enhanced thermostability. The triple mutant, K75E/K363E/K420E, was found to be the best with a 7.3-fold increase in half-life (t1/2) at 33 °C compared to that of the wild-type (WT). Most importantly, this mutant showed comparable enzymatic activity to that of the WT protein. Structural modelling demonstrated that increased surface charge-charge interactions and optimization of surface hydrophobic and electrostatic contacts contributed to the improved thermostability displayed by K75E/K363E/K420E.

Capsaicin Protects Against Oxidative Insults and Alleviates Behavioral Deficits in Rats with 6-OHDA-Induced Parkinson's Disease via Activation of TRPV1.

Increasing evidence suggests that capsaicin may play a role in modulating neuronal function and controlling motor behavior. However, the underlying mechanism is still unclear and the activation of transient receptor potential vanilloid 1 (TRPV1) might be involved in. This study investigated the potential neuroprotective role of capsaicin in a rat model of 6-hydroxydopamine (6-OHDA)-induced Parkinson's disease (PD). Capsaicin was treated intraperitoneally for the 6-OHDA induced PD rats and the locomotor activity and abnormal involuntary movements were found alleviated. Besides, brain oxidative stress (lipid peroxidation, superoxide dismutase and catalase) was also assessed, and oxidative insults were investigated relieved. Both the expression of tyrosine hydroxylase and TRPV1 were increased in the striatal and substantia nigra areas of 6-OHDA induced rats after the treatment of capsaicin by the semi-quantitative analysis of Western Blot. And the immunostaining of substantia nigra further suggested that capsaicin might protect against dopaminergic neuronal loss. Our results showed that TRPV1 might be a novel therapeutic target for PD.

Pseudoruegeria marinistellae sp. nov., isolated from an unidentified starfish in Sanya, China.

A taxonomic study was carried out on a Gram-stain negative, rod-shaped, non-flagellated, and facultatively anaerobic bacterial strain designated as strain SF-16T, which was isolated from an unidentified starfish in Sanya, China. Strain SF-16T was found to be 5.0-7.0 µm long, and oxidase and catalase positive. Cell growth was observed at pH 6.0-8.5 (optimum, 7.0-8.0), temperatures of 10-41 °C (optimum, 25-30 °C), and salinities of 0-12 % (optimum, 3.0-6.0 %). The predominant fatty acids (>20 %) were found to be C18:1 ω7c and/or C18:1 ω6c (summed feature 8). Ubiquinone 10 was identified as the predominant quinone for strain SF-16T. The polar lipids were identified as diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, two unidentified aminolipids, two unidentified lipids, and three unidentified phospholipids. The DNA G+C content of the genomic DNA of strain SF-16T was determined to be 63.0 mol%. Phylogenetic analysis based on the 16S rRNA gene showed that strain SF-16T belongs to the genus Pseudoruegeria and is closely related to Pseudoruegeria sabulilitoris GJMS-35T (98.42 % similarity). The ANI value between strain SF-16T and P. sabulilitoris GJMS-35T was found to be 74.98 %, and DNA-DNA hybridization value was 21.1 ± 2.3 % in silico and 57 % in vitro. Based on the low level of the genetic relatedness, phylogenetic and phenotypic data, a novel species Pseudoruegeria marinistellae sp. nov. is proposed. The type strain is SF-16T (=MCCC 1K01155T = KCTC 42910T).

Serum Growth Differentiation Factor 15 in Parkinson Disease.

BACKGROUND: Growth differentiation factor 15 (GDF15) has been shown to be protective for dopaminergic neurons in animal and ex vivo experiments. However, little is known about its effect on the human body. OBJECTIVE: This study investigated associations between serum GDF15 levels and clinical parameters in patients with Parkinson disease (PD). METHODS: Idiopathic PD patients (n = 104) and age-matched controls (n = 88) were enrolled. Serum GDF15 levels were measured by human enzyme-linked immunosorbent assay. Univariate and multivariate analyses investigated correlations between GDF15 and clinical characteristics, including disease severity by the Unified PD Rating Scale (UPDRS)-III. The diagnostic value of GDF15 was evaluated by receiver-operating characteristic curve (ROC) analysis. RESULTS: The serum GDF15 levels of the PD patients were significantly higher than those of the healthy controls. In PD patients, serum GDF15 levels in men were significantly higher than in women. GDF15 levels correlated with age, gender, disease duration, and UPDRS-III score. After adjusting for confounding factors, multiple linear regression analysis showed that the serum GDF15 level (ß = 0.015, p = 0.001) was an independent risk factor for UPDRS-III score. In ROC analysis, GDF15 achieved an area under the curve of 0.86 for the identification of PD, with a sensitivity of 71.15% and a specificity of 87.50%. CONCLUSION: GDF15 may be a potential biomarker for the diagnosis and monitoring of motor severity in PD.

Structures of PspAG97A α-glucoside hydrolase reveal a novel mechanism for chloride induced activation.

Here we report the first crystal structure of a secretory α-glucoside hydrolase isolated from Pseudoalteromonas sp. K8, PspAG97A, which belongs to glycoside hydrolase family 97 and exhibits halophilic property. PspAG97A lacks an acidic surface, that is considered essential for protein stability at high salinity. Interestingly, PspAG97A unusually contains a chloride ion coordinated by the guanidinium group of Arg171 and the main chain amide groups of Tyr172 and Glu173 at the active site. The structures of PspAG97A complexed with acarbose and panose demonstrate that residues Glu173, Arg171 and Asn170 for subsite +1 decide the substrate specificity of the enzyme for the α-1,6-glucosidic linkage. Structural alterations observed in the R171K variant and enzyme kinetic experiments focusing on chloride assisted activation suggest that the active site chloride serves to properly orient Glu173, Arg171 and Asn170 to facilitate substrate recognition. Furthermore, the chloride assists the binding of Glu173 to the conserved calcium ion and plays an essential role in properly positioning the base catalyst Glu456. In sum, our results provide valuable insight into the structural basis of protein halophilicity.

Oroxylin A regulates glucose metabolism in response to hypoxic stress with the involvement of Hypoxia-inducible factor-1 in human hepatoma HepG2 cells.

Metabolic alteration in cancer cells is one of the most conspicuous characteristics that distinguish cancer cells from normal cells. In this study, we investigated the influence and signaling ways of oroxylin A affecting cancer cell energy metabolism under hypoxia. The data showed that oroxylin A remarkably reduced the generation of lactate and glucose uptake under hypoxia in HepG2 cells. Moreover, oroxylin A inhibited HIF-1α expression and its stability. The downstream targets (PDK1, LDHA, and HK II), as well as their mRNA levels were also suppressed by oroxylin A under hypoxia. The silencing or the overexpression of HIF-1α assays suggested that HIF-1α is required for metabolic effect of oroxylin A in HepG2 cells during hypoxia. Furthermore, oroxylin A could reduce the expression of complex III in mitochondrial respiratory chain, and then decrease the accumulation of ROS at moderate concentrations (0-50 µM) under hypoxia, which was benefit for its inhibition on glycolytic activity by decreasing ROS-mediated HIF-1 expression. Besides, oroxylin A didn't cause the loss of MMP under hypoxia and had no obvious effects on the expression of OXPHOS complexes, suggesting that oroxylin A did not affect mitochondrial mass at the moderate stress of oroxylin A. The suppressive effect of oroxylin A on glycolysis led to a significantly repress of ATP generation, for ATP generation mostly depends on glycolysis in HepG2 cells. This study revealed a new aspect of glucose metabolism regulation of oroxylin A under hypoxia, which may contribute to its new anticancer mechanism. © 2015 Wiley Periodicals, Inc.

Spectroscopic and QM/MM investigations of Chloroperoxidase catalyzed degradation of orange G.

Chloroperoxidase (CPO), a heme-thiolate protein, from Caldariomyces fumago catalyzes a plethora of reactions including halogenation, dismutation, epoxidation, and oxidation. Although all CPO-catalyzed reactions go through a common intermediate, compound I, different mechanisms are followed in subsequent transformations. To understand the mechanism of CPO-catalyzed halide-dependent degradation of orange G, the role of halide and pH was systematically investigated. It is revealed that formation and protonation of compound X, a long-sought after hypochlorite heme adduct intermediate existed during CPO-catalyzed halide-dependent reactions, significantly lowers the reaction barrier and increases the efficiency of CPO-catalyzed orange G degradation. The extremely acidic optimal reaction pH suggests the protonation of a residue, presumably, Glu 183 in CPO catalysis. Halide dependent studies showed that Kcat is higher in the presence of Br(-) than in the presence of Cl(-). The degradation products of orange G indicate the cleavage at a single position of orange G, demonstrating a high regioselectivity of CPO-catalyzed degradation. Based on our kinetic, NMR and QM/MM studies, the mechanism of CPO-catalyzed orange G degradation was proposed.

Lutimaribacter marinistellae sp. nov., isolated from a starfish.

A taxonomic study was carried out on a Gram-staining-negative bacterium, strain SF-12T, isolated from an unidentified starfish living in Sanya, PR China. Cells of SF-12T were non-spore-forming rods, 0.5-0.8 µm wide, 2.2-2.5 µm long and motile by means of flagella. SF-12T was facultatively anaerobic, heterotrophic, oxidase- and catalase-positive. Growth of SF-12T occurred at 15-38 °C (optimum, 30 °C), at pH 6.5-8.5 (optimum, pH 7.0), and in the presence of 2.0-7.0 % (w/v) NaCl (optimum, 3.0-4.0 %). The predominant fatty acids of SF-12T were C18 : 1ω7c and/or C18 : 1ω6c. Ubiquinone 10 was the sole respiratory quinone of SF-12T. The major polar lipids of SF-12T were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, three unknown aminolipids, and seven unknown phospholipids. The DNA G+C content was 61 mol%. SF-12T showed the highest 16S rRNA gene sequence similarity to Lutimaribacter pacificus W11-2BT (96.06 %), followed by Cribrihabitans neustonicus CC-AMHB-3T (96.02 %), Lutimaribacter saemankumensis SMK-117T (96.0 %), Cribrihabitans marinus CZ-AM5T (95.92 %), Lutimaribacter litoralis KU5D5T (95.92 %) and other species of the family Rhodobacteraceae(<95.9 %). However, phylogenetic trees based on 16S rRNA gene sequences showed that SF-12T formed a lineage with members of the genus Lutimaribacter in the trees. On the basis of phenotypic, chemotaxonomic and phylogenetic analyses, SF-12T is considered to represent a novel species of the genus Lutimaribacter, for which the name Lutimaribacter marinistellae sp. nov. is proposed. The type strain is SF-12T (=MCCC 1K01154T=KCTC 42911T).

A cold-adapted and glucose-stimulated type II α-glucosidase from a deep-sea bacterium Pseudoalteromonas sp. K8.

OBJECTIVES: To express and characterize a putative α-glucosidase, Pagl, from Pseudoalteromonas sp. K8 obtained via genome mining approach. RESULTS: Pagl was expressed and purified to homogeneity, with a molecular mass of 60 kDa. It was optimally active at pH 8.5 and 30 °C, and showed cold-adapted activity. Pagl exhibited specific activity towards substrates with α-1,4-linkage, with the highest specific activity of 19.4 U/mg for maltose, followed by pNPαG and maltodextrins, suggesting that Pagl belongs to the type II α-glucosidase. Interestingly, the activity of Pagl is significantly enhanced (2.7 times) in the presence of 200 mM glucose. CONCLUSION: The unique catalytic properties of Pagl make it an attractive candidate for several industrial applications.

A novel ethanol-tolerant laccase, Tvlac, from Trametes versicolor.

OBJECTIVES: To produce and characterize novel laccases with ethanol tolerance from Trametes versicolor using agriculture by-products as energy source. RESULTS: Trametes versicolor 1017 produces two laccase isoenzymes with a total activity of 10 U ml(-1) within 8 days when using wheat bran and peanut powder as energy sources in liquid culture medium. A novel isoenzyme, named Tvlac, was identified, purified and characterized. Its optimum pH and temperature were from 4.5 to 5 and 55 to 60 °C, respectively. Its activity was stimulated by ethanol at 10 % (v/v) which increased the V 0. CONCLUSIONS: The biochemical properties of Tvlac substantiate the potential of this enzyme for applications under an aqueous ethanol mixture environment.