Avian pathogenic Escherichia coli (APEC) causes colibacillosis in poultry, resulting in severe economic losses worldwide. Coliphages represent alternative antibacterial substitutes based on high lytic efficiency and few side-effects. However, the complete genome sequences information of APEC phages are limited, and knowledge of undesired genes and the narrow host range restrict their applications. In this study, we isolated a virulent phage QL01, with a relatively broad lytic spectrum (41 of 78 APEC strains). Transmission electron micrography showed it belonged to the family Myoviridae with an elongated head and a contractile tail. Whole genome sequencing revealed a linear double-stranded DNA (170,527 kb; GC content, 39.6%) with 275 possible ORFs. Comparative genome analysis revealed high homology between QL01 and other T4-like phages. However, it also showed some unique features, for example, ORF142 and ORF143, which encode IP9 and IP8, respectively, and may counteract host resistance only exist in a few T4-like phages such as IME08 and vB_EcoM_VR5. Furthermore, phage therapy in artificially infected ducks showed a 26.67% decrease in mortality compared with the untreated group. Our study indicates the potential antibacterial function of phage QL01 against APEC infections and highlights unique molecular features underlying the relatively broad host range.
We
described a Ni-bidentate oxazoline catalyzed highly enantio-
and diastereoselective decarboxylative aldol reaction of 2-oxotetrahydrofuran-3-carboxylic
acid/2-oxochromane-3-carboxylic acid derivatives with different kinds
of carbonyls. Under optimal reaction conditions, α-substituted
β-hydroxy butyrolactones and dihydrocoumarins with an all-carbon
quaternary stereocenter have been generated with high levels of functional-group
compatibility. Furthermore, proficient transformations of products
were also described, in which an aliphatic tertiary alcohol and a
multi-substituted 1,4-diol were smoothly constructed through hydrogenation
and ring-opening reaction, respectively.
A Yb(OTf)3 catalyzed [1,3]-rearrangement of 3- alkenyl oxindoles was achieved, affording a variety of multifunctional 3-ylideneoxindoles with good yields and Z/E selectivities (64%-89% yield, 78:22->99:1 Z/E). Importantly, an operationally simple, one-pot sequential...
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