The brilliant but mentally unstable inventor of a device capable of remotely overloading and destroying any active electrical or electronic circuit is attempting to destroy Probe Control.

a projecting, pipelike device on a receiving aircraft used to make connection with and receive fuel from a tanker aircraft during refueling in flight. X. Y. Jia, Z. H. Tian, L. Shao, X. D. Qu, Q. F. Zhao, J. Tang, G. L. Tang and W. Liu, Chem. Biol., 2006, 13, 575–585 CrossRef CAS PubMed. Scheme 1 Genome mining of novel tetracycline gene clusters. (A) Structures of known tetracyclines, (B) the BGCs of known tetracyclines where only resistant genes and KS and CLFs are highlighted in colors, and (C) workflow of the genome mining in this work. 21 393 actinobacteria genome annotation files from the NCBI database; the first round of search probes is based on adjacent regulators and transporters. Within the range of 30 genes near the regulator, the adjacent KS and CLF were used as the probe for the second-round search. Eligible 1744 gene clusters were screened for further analysis. (D) The phylogenetic tree of 1744 CLFs and (E) the genome neighboring network of 30 tetracycline gene clusters ( E = 10 −10).

Frequently Asked Questions

Well, seeing as there was a new episode the following week, you can pretty well guess how that went.

Z. Feng, D. Kallifidas and S. F. Brady, Proc. Natl. Acad. Sci. U. S. A., 2011, 108, 12629–12634 CrossRef CAS PubMed.Had this and "One of our Probes . . ." been aired in production number sequence, this would have introduced Burrell; dialogue when Burrell takes over Harding's station suggests this was the intent. Similarly, MarR controls the expression of a multidrug efflux pump. 20 As all known tetracycline BGCs share this resistant mechanism, we reasoned that this pair of genes could be a good indicator for mining tetracycline-type natural products. The show was created by Leslie Stevens, and produced by Stevens, Robert H. Justman, John Strong [2] and Anthony Spinner. [3] The high concept was described as "science fiction in today's world" and the episodes featured many high-tech elements which are now considered common in current science fiction shows. Grover is tasked with first finding, then protecting, the pacifistic, race-car-driving, "madcap heiress" of an Italian weapons magnate, on the run from a family bent on stopping her from formally taking possession of a trust that would give her control of the family business. W. J. Zhang, B. D. Ames, S. C. Tsai and Y. Tang, Appl. Environ. Microbiol., 2006, 72, 2573–2580 CrossRef CAS PubMed.

Albert Popwell as Albert Griffin, linguist and code-breaker; former chief translator at the United Nations E. Q. King, C. N. Lewis, H. Welch, E. A. Clark, J. B. Johnson, J. B. Lyons, R. B. Scott and P. B. Cornely, J. Am. Med. Assoc., 1950, 143, 1–4 CrossRef CAS PubMed. We noticed that the identified BGCs included many known BGCs for type II polyketide biosyntheses such as enterocin, 23 landomycin, 24 and tetracenomycin, 25 indicating that they also share a similar resistance mechanism (Fig. S1 †). To directly target the tetracycline BGC, we attempted to analyze the CLFs, whose phylogeny highly correlates with the polyketide condensation number and cyclization pattern. 26,27 To test if the tetracycline BGCs are in a separate clade, we first generated a phylogenetic tree using CLFs from over 160 characterized BGCs for type II PKS. Indeed, we found that the compounds with different extension lengths and cyclization patterns can be well distinguished (Fig. S2 †). Gratifyingly, we observed that five known CLFs from tetracycline BGCs are grouped together, although they are closely related to the BGC from cervimycin, supporting the feasibility of the CLF phylogeny in reflecting the product structure. Thus, the CLF sequences from 1744 BGCs were extracted and a phylogenetic tree was then constructed ( Scheme 1D). The most abundant BGCs are angucyclines. Meanwhile spore pigment, naphthoquinone, pentangular polyphenol, and anthracycline BGCs were also widely distributed, indicating that the TetR/MarR-transporter resistance mechanism is widespread in the type II PKS biosynthetic pathway. Notably, we observed a small group that contained 103 CLFs including 5 known tetracycline CLFs clustered together. Among them, 72.8% are from Streptomyces, 14.5% are from Kitasatospora, 4.8% are from Amycolatopsis, and the others are from rare actinomycetes like Spongiactinospora and Micromonospora, indicating a wide spread of tetracycline BGCs in various strains (Fig. S3 †). After dereplication, we obtained 25 BGCs that are distinct from all characterized tetracycline BGCs in the literature (Fig. S4 and Tables S3–S27 †).To simplify the structure elucidation procedure, we attempted to dissect the sugar linkage in 1 through acid hydrolysis. The treatment of 1 with trifluoroacetic acid/MeOH/H 2O (1 : 1 : 8) at 60 °C for 1 hour led to the complete hydrolysis of 1 and afford three major fragments 1a ( m/ z 658.2501 [M − H] −), 1b ( m/ z 329.0794 [M − H] −) and 1c ( m/ z 483.1390 [M + Na] +). Compound 1a was elucidated to have the same tetracyclic aglycon as observed in SF2575 (Table S30 †). 16,30 Meanwhile the 1H– 1H COSY spectrum showed that the sugars in 1a were different to that in SF2575. The diagnostic HMBC correlations between H8/C1A, H1A/C8, H1A/C9, and H1B/C13 indicated that two sugar moieties were anchored at C9 and N1 positions, respectively. The relative configuration of sugar moieties was determined by the interpretation of the NOESY data and coupling constants. The large diaxial coupling constants, J H1A = 11.1 Hz, and NOE correlations of H1A with H5A, and H2Aβ with H4A indicated that H1A, H4A, and H5A all possessed axial orientations. Thus, sugar A was determined to be amicetose. Similarly, based on NMR analysis, sugar B was also determined to be amicetose. Fragment 1b was elucidated to have two subunits including 5-chloro-6-methylsalicylic acid and a methylated oliose, the stereochemistry of which was determined by NOE analysis (Table S31 †). The HMBC correlation of H4F with C1′ suggested the oliose was substituted at the C1′ position. Compared to 1b, fragment 1c has an additional oliose moiety at the C1F position as determined by the HMBC correlation of H3E/C1F and H4F/C1′ (Table S32 †). After further scrutiny of the NMR data of 1, two additional sugar moieties, sugar C and sugar D, were identified. The diagnostic HMBC correlations H1B/C13, H1C/C4B, H4C/C1′′, H2′′/C1′′, H1D/C12a, H8/C1A, H4A/C1E, H3E/C1F, H4F/C1′, and 1H– 1H COSY of H1B with NH, linked all units, established the complete structure of 1 and designated as hainancycline ( Scheme 2B and Table S29 †). To the best of our knowledge, 1 represents the most modified tetracycline discovered so far. Biosynthesis of the aglycon of hainancycline To investigate the biosynthetic pathway for 1, we analyzed the hai BGC in detail. The hai BGC (GenBank accession number ON755207) spans a ∼55 kb contiguous DNA region consisting of 43 genes responsible for biosynthesis, regulation, and resistance ( Scheme 2A). As the aglycon of 1 was identical to SF2575, we carefully compared these two BGCs. The hai BGC encoded all homologous proteins required for aglycon biosynthesis in SF2575 with moderate to high sequence identities (50–80%) (Table S3 and Fig. S7 †). 30 Thus, we proposed that the tetracycline core in 1 was biosynthesized in a similar manner to that in the SF2575 pathway. We thus collected all assembled genome annotation files from the NCBI database which included over 20 000 genomes (June 2021). Surprisingly, using tetR/ marR and the adjacent transporter gene as probes, we found 351 172 BGCs. These BGCs are not all tetracycline biosynthesis-related, because many strains acquired the tetracycline-resistant genes due to the prolonged and extensive use of tetracyclines in the world. 21,22 We reasoned that the minimal PKS genes, which are responsible for the assembly of the tetracycline carbon skeleton, should also be colocalized with the resistance genes in the potential tetracycline gene cluster ( Scheme 1B). Thus, we took the conserved ketosynthase (KS) and chain length factor (CLF) into consideration. Based on this, an algorithm was developed that can identify various BGCs in which the tetR/ marR and transporter genes are colocalized within a 30 gene distance with KS and CLF genes. This refinement resulted in 1744 BGCs, among which all known tetracycline BGCs were obtained, confirming the reliability of this approach. In contrast to the widespread tetracycline-resistant strains and a large number of type II PKS BGCs in actinobacteria, our first genome analysis using a resistance gene and type II PKS gene as probes resulted in only ∼1700 BGCs from over 20 000 genomes in the public database, encouraging us to perform further analysis.