Alcanivorax dieselolei strain B-5 is a marine bacterium that can utilize a broad range of n-alkanes (C(5) -C(36) ) as sole carbon source. However, the mechanisms responsible for this trait remain to be established. Here we report on the characterization of four alkane hydroxylases from A. dieselolei, including two homologues of AlkB (AlkB1 and AlkB2), a CYP153 homologue (P450), as well as an AlmA-like (AlmA) alkane hydroxylase. Heterologous expression of alkB1, alkB2, p450 and almA in Pseudomonas putida GPo12 (pGEc47ΔB) or P. fluorescens KOB2Δ1 verified their functions in alkane oxidation. Quantitative real-time RT-PCR analysis showed that these genes could be induced by alkanes ranging from C(8) to C(36) . Notably, the expression of the p450 and almA genes was only upregulated in the presence of medium-chain (C(8) -C(16) ) or long-chain (C(22) -C(36) ) n-alkanes, respectively; while alkB1 and alkB2 responded to both medium- and long-chain n-alkanes (C(12) -C(26) ). Moreover, branched alkanes (pristane and phytane) significantly elevated alkB1 and almA expression levels. Our findings demonstrate that the multiple alkane hydroxylase systems ensure the utilization of substrates of a broad chain length range.

Despite extensive efforts, the electrocatalytic reduction of water using homogeneous/heterogeneous Fe, Co, Ni, Cu, W, and Mo complexes remains challenging because of issues involving the development of efficient, recyclable, stable, and aqueous-compatible catalysts. In this study, evolution of the de novo designed dinitrosyl iron complex DNIC-PMDTA from a molecular catalyst into a solid-state hydrogen evolution cathode, considering all the parameters to fulfill the electronic and structural requirements of each step of the catalytic cycle, is demonstrated. DNIC-PMDTA reveals electrocatalytic reduction of water at neutral and basic media, whereas its deposit on electrode preserves exceptional longevity, 139 h. This discovery will initiate a systematic study on the assembly of [Fe(NO)2] motif into current collector for mass production of H2, whereas the efficiency remains tailored by its molecular precursor [(L)Fe(NO)2].

Two bacterial strains, M-5T and WP0211T, were isolated from the surface water of a waste-oil pool in a coastal dock and from a deep-sea sediment sample from the West Pacific Ocean, respectively. Analysis of 16S rRNA gene sequences indicated that both strains belonged to the class Alphaproteobacteria and were closely related to Thalassospira lucentensis (96.1 and 96.2 %, gene sequence similarity, respectively). Based on the results of physiological and biochemical tests, as well as DNA–DNA hybridization experiments, it is suggested that these isolates represent two novel species of the genus Thalassospira. Various traits allow both novel strains to be differentiated from Thalassospira lucentensis, including oxygen requirement, nitrate reduction and denitrification abilities and major fatty acid profiles, as well as their ability to utilize six different carbon sources. Furthermore, the novel strains may be readily distinguished from each other by differences in their motility, flagellation, growth at 4 °C and 40 °C, their ability to hydrolyse Tween 40 and Tween 80, their utilization of 19 different carbon sources and by quantitative differences in their fatty acid contents. It is proposed that the isolates represent two novel species for which the names Thalassospira xiamenensis sp. nov. (type strain, M-5T=DSM 17429T=CGMCC 1.3998T) and Thalassospira profundimaris sp. nov. (type strain, WP0211T=DSM 17430T=CGMCC 1.3997T) are proposed.

Alcanivorax hongdengensis sp. nov., an alkanedegrading bacterium isolated from surface seawater of the straits of Malacca and Singapore, producing a lipopeptide as its biosurfactant A taxonomic study was carried out on strain A-11-3 T , which was isolated from an oil-enriched consortia from the surface seawater of Hong-Deng dock in the Straits of Malacca and Singapore. Cells were aerobic, Gram-negative, non-spore-forming irregular rods. The strain was catalaseand oxidase-negative. It grew on a restricted spectrum of organic compounds, including some organic acids and alkanes. 16S rRNA gene sequence comparisons showed that strain A-11-3 T was most closely related to the type strains of Alcanivorax jadensis (96.8 % sequence similarity), Alcanivorax borkumensis (96.8 %), Alcanivorax dieselolei (94.8 %), Alcanivorax venustensis (94.2 %) and Alcanivorax balearicus (94.0 %). The predominant fatty acids were C 16 : 0 (31.2 %), C 18 : 1 v7c (24.8 %), C 18 : 0 (9.6 %), C 12 : 0 (8.3 %), C 16 : 1 v7c (8.3 %) and C 16 : 0 3-OH (5.1 %). The G+C content of the genomic DNA was 54.7 mol%. Moreover, the strain produced lipopeptides as its surface-active compounds. According to physiological and biochemical tests, DNA-DNA hybridization results and sequence comparisons of the 16S-23S internal transcribed spacer, the gyrB gene and the alkane hydroxylase gene alkB1, strain A-11-3 T was affiliated with the genus Alcanivorax but could be readily distinguished from recognized Alcanivorax species. Therefore strain A-11-3 T represents a novel species of the genus Alcanivorax for which the name Alcanivorax hongdengensis sp. nov. is proposed. The type strain is A-11-3 T (5CGMCC 1.7084 T 5LMG 24624 T 5MCCC 1A01496 T ).Alcanivorax-like bacteria have now been detected in oilimpacted environments across the globe (Head et al., 2006). The genus Alcanivorax currently includes five species, Alcanivorax borkumensis, A. jadensis, A. venustensis, A. dieselolei and A. balearicus, all of which were isolated from marine environments except A. balearicus, which was isolated from a subterranean saline lake (Yakimov et al., 1998;Bruns & Berthe-Corti, 1999; Fernández-Martínez et al., 2003;Liu & Shao, 2005a;Rivas et al., 2007). In this study, we isolated a novel strain, designated A-11-3 T , from an oil-enriched consortium. Characterization using a polyphasic approach and classification of strain A-11-3 T showed that it was phylogenetically related to members of the genus Alcanivorax.Surface seawater was sampled while passing through the Straits of Malacca and Singapore on the research vessel DaYang Yi-Hao in December 2005, from the site S74 (102 u 25.819 E 1 u 48.159 N) near the Hong-Deng dock of Singapore. Enrichment was started on-board immediately after sampling. About 100 ml of the sample was loaded into sterile tubes and supplemented with 1 ml sterilized NH 4 NO 3 (100 g l 21 ) and KH 2 PO 4 (50 g l 21 ), 100 ml FeSO 4 .7H 2 O (2.8 g l 21 ) and 0.5 ml diesel fuel. In the laboratory about 1 month later, 1 ml enriched culture was transferred into 100 ...

Aims: Ansamycins are a family of macrolactams that are synthesized by type I polyketide synthase (PKS) using 3-amino-5-hydroxybenzoic acid (AHBA) as the starter unit. Most members of the family have strong antimicrobial, antifungal, anticancer and/or antiviral activities. We aimed to discover new ansamycins and/or other AHBA-containing natural products from actinobacteria. Methods and Results: Through PCR screening of AHBA synthase gene, we identified 26 AHBA synthase gene-positive strains from 206 plant-associated actinomycetes (five positives) and 688 marine-derived actinomycetes (21 positives), representing a positive ratio of 2Á4-3Á1%. Twenty-five ansamycins, including eight new compounds, were isolated from six AHBA synthase genepositive strains through TLC-guided fractionations followed by repeated column chromatography. To gain information about those potential ansamycin gene clusters whose products were unknown, seven strains with phylogenetically divergent AHBA synthase genes were subjected to fosmid library construction. Of the seven gene clusters we obtained, three show characteristics for typical ansamycin gene clusters, and other four, from Micromonospora spp., appear to lack the amide synthase gene, which is unusual for ansamycin biosynthesis. The gene composition of these four gene clusters suggests that they are involved in the biosynthesis of a new family of hybrid PK-NRP compounds containing AHBA substructure. Conclusions: PCR screening of AHBA synthase is an efficient approach to discover novel ansamycins and other AHBA-containing natural products. Significance and Impact of the Study: This work demonstrates that the AHBAbased screening method is a useful approach for discovering novel ansamycins and other AHBA-containing natural products from new microbial resources.

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We investigated the device performance of the optimized 3-nm gate length (L G ) bulk Silicon FinFET device using 3-D quantum transport device simulation. By keeping source and drain doping constant and by varying only the channel doping, the simulated device is made to operate in three different modes such as inversion (IM) mode, accumulation (AC) mode and junctionless (JL) mode. The excellent electrical characteristics of the 3-nm gate length Si-based bulk FinFET device were investigated. The sub threshold slope values (SS~65mV/dec.) and drain-induced barrier lowering (DIBL<17mV/V) are analyzed in all three IM, AC and JL modes bulk FinFET with |V TH | ~0.31 V. Furthermore, the threshold voltage (V TH ) of the bulk FinFET can be easily tuned by varying the work function (WK). This research reveals that Moore's law can continue up to 3-nm nodes.