RESUMEN
Interkingdom competition occurs between hymenopteran parasitoids and insect viruses sharing the same insect hosts. It has been assumed that parasitoid larvae die with the death of the infected host or as result of competition for host resources. Here we describe a gene family, parasitoid killing factor (pkf), that encodes proteins toxic to parasitoids of the Microgastrinae group and determines parasitism success. Pkfs are found in several entomopathogenic DNA virus families and in some lepidopteran genomes. We provide evidence of equivalent and specific toxicity against endoparasites for PKFs found in entomopoxvirus, ascovirus, baculovirus, and Lepidoptera through a mechanism that elicits apoptosis in the cells of susceptible parasitoids. This highlights the evolutionary arms race between parasitoids, viruses, and their insect hosts.
Asunto(s)
Entomopoxvirinae/fisiología , Proteínas de Insectos/toxicidad , Lepidópteros/parasitología , Lepidópteros/virología , Proteínas Virales/toxicidad , Avispas/fisiología , Animales , Apoptosis , Evolución Biológica , Transferencia de Gen Horizontal , Genoma de los Insectos , Interacciones Huésped-Parásitos , Proteínas de Insectos/química , Proteínas de Insectos/genética , Proteínas de Insectos/metabolismo , Virus de Insectos/fisiología , Larva/genética , Larva/parasitología , Larva/virología , Lepidópteros/genética , Lepidópteros/metabolismo , Nucleopoliedrovirus/fisiología , Spodoptera/genética , Spodoptera/metabolismo , Spodoptera/parasitología , Spodoptera/virología , Proteínas Virales/química , Proteínas Virales/genética , Proteínas Virales/metabolismo , Avispas/crecimiento & desarrolloRESUMEN
Baculoviruses have two forms, occlusion derived virus (ODV) which is responsible for primary infection in host midgut tissue and budded virus (BV), which infects all other host tissues during secondary infection. This study examined the primary infection by ODV of midgut cells of bertha armyworm Mamestra configurata fourth instar larvae and measured the expression of viral genes over a time course of infection. Both digital PCR and RNA sequencing methods showed the profile of transcription to be different from those produced by AcMNPV BV infection of in vitro cell cultures. This included having unique collections of genes expressed early, as well as much greater late gene expression of p6.9 and much reduced expression of polh and p10. These differences likely reflect characteristics unique to the critical step of in vivo midgut cell infection, and provide insights into the processes that regulate viral gene expression in different host tissues.
Asunto(s)
Baculoviridae/genética , Tracto Gastrointestinal/virología , Regulación Viral de la Expresión Génica , Mariposas Nocturnas/virología , Animales , Secuenciación de Nucleótidos de Alto Rendimiento , Larva/virología , Sistemas de Lectura Abierta , Reacción en Cadena en Tiempo Real de la Polimerasa , Transcripción Genética , TranscriptomaRESUMEN
The structure of the PA1607 protein from Pseudomonas aureginosa was determined at 1.85 A resolution using the Se-Met multiwavelength anomalous diffraction (MAD) technique. PA1607 forms a dimer and adopts a winged-helix motif similar to the MarR family of transcription regulators, though it has an unusual dimerization profile. The DNA-binding regions and a putative metal-binding site are not conserved in PA1607.
Asunto(s)
Proteínas Bacterianas/química , Pseudomonas aeruginosa/metabolismo , Factores de Transcripción/química , Secuencia de Aminoácidos , Secuencia Conservada , Cristalografía por Rayos X , Dimerización , Modelos Moleculares , Datos de Secuencia Molecular , Estructura Secundaria de Proteína , Alineación de SecuenciaRESUMEN
(1R,6R)-2-Succinyl-6-hydroxy-2,4-cyclohexadiene-1-carboxylate (SHCHC) synthase, also called MenD, participates in the menaquinone (vitamin K2) biosynthetic pathway. The enzyme is a part of the superfamily of ThDP-dependent enzymes; however, it is the only enzyme known to catalyze a Stetter-like 1,4-addition of a ThDP adduct to the beta-carbon of an unsaturated carboxylate. This is the first reported crystallization of the apoenzyme and holoenzyme forms of MenD. The apoenzyme crystals were obtained by sitting-drop vapour diffusion with 70% MPD. However, the crystals were too small to collect diffraction data and a search for better conditions was not successful. Single crystals of the holoenzyme with ThDP and Mn2+ as cofactors were obtained by the hanging-drop vapour-diffusion method with 35% ethylene glycol as precipitant. Diffraction data were collected on a cryocooled crystal to a resolution of 2.0 A at BioCARS, Advanced Photon Source (APS), Chicago, IL, USA. The crystal was found to belong to space group P2(1)2(1)2(1), with unit-cell parameters a = 106.86, b = 143.06, c = 156.85 A, alpha = beta = gamma = 90 degrees.
