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Mosquitoes transmit medically important human pathogens, including viruses like dengue virus and parasites such as Plasmodium spp., the causative agent of malaria. Mosquito microbiomes are critically important for the ability of mosquitoes to transmit disease-causing agents. However, while large collections of bacterial isolates and genomic data exist for vertebrate microbiomes, the vast majority of work in mosquitoes to date is based on 16S rRNA gene amplicon data that provides limited taxonomic resolution and no functional information. To address this gap and facilitate future studies using experimental microbiome manipulations, we generated a bacterial Mosquito-Associated Isolate Collection (MosAIC) consisting of 392 bacterial isolates with extensive metadata and high-quality draft genome assemblies that are publicly available, both isolates and sequence data, for use by the scientific community. MosAIC encompasses 142 species spanning 29 bacterial families, with members of the Enterobacteriaceae comprising 40% of the collection. Phylogenomic analysis of 3 genera, Enterobacter, Serratia, and Elizabethkingia, reveal lineages of mosquito-associated bacteria isolated from different mosquito species in multiple laboratories. Investigation into species' pangenomes further reveals clusters of genes specific to these lineages, which are of interest for future work to test for functions connected to mosquito host association. Altogether, we describe the generation of a physical collection of mosquito-associated bacterial isolates, their genomic data, and analyses of selected groups in context of genome data from closely related isolates, providing a unique, highly valuable resource for research on bacterial colonisation and adaptation within mosquito hosts. Future efforts will expand the collection to include broader geographic and host species representation, especially from individuals collected from field populations, as well as other mosquito-associated microbes, including fungi, archaea, and protozoa. Mosquito microbiomes have an important role in disease transmission. This study presents MosAIC (Mosquito-Associated Isolate Collection), a collection of 392 mosquito-associated bacterial isolates and their genomic data, all publicly available and thus a valuable resource to study bacterial colonization and adaptation in mosquitoes. [ABSTRACT FROM AUTHOR] more...

Using the complete genome sequence from Agrobacterium tumefaciens C58, the authors identified a secondary metabolite gene cluster that encodes the biosynthesis of a metabolite with siderophore activity. Support for this conclusion came from genetic and regulatory analysis of the gene cluster, along with the purification of a metabolite from A. tumefaciens C58 with iron-chelating activity. Genetic analysis of mutant strains disrupted in this gene cluster showed that these strains grew more slowly than the wild-type strain in medium lacking iron. Additionally, the mutant strains failed to produce a chrome-azurol-S-reactive material in liquid or solid medium, and failed to produce the metabolite with iron-chelating characteristics that was identified in the wild-type strain. Addition of this purified metabolite to the growth medium of a mutant strain restored its ability to grow in iron-deficient medium. Furthermore, expression of this gene cluster was induced by growth under iron-limiting conditions, suggesting that expression of this gene cluster occurs when iron is scarce. These data are all consistent with the proposal that the proteins encoded by this gene cluster are involved in the production of a siderophore. Interestingly, these proteins show the highest level of amino acid similarity to proteins from a gene cluster found in the filamentous cyanobacterium Nostoc sp. PCC7120, rather than to known siderophore biosynthetic enzymes. Given these properties, it is proposed that the siderophore produced by A. tumefaciens C58 will have a unique chemical structure. Production of the siderophore was not required for virulence of A. tumefaciens when tested with a standard stem inoculation assay. more...

Research has been conducted on the colored triaryl cation antibiotic. The isolation and characterization of these antibiotics produced in Escherichia coli by the members of the metagenomic DNA library have been carried out and discussed. more...

Research has been conducted on microbial diversity in nature. The libraries of genomic DNA isolated from soil have been constructed to investigate the extent of microbial diversity.

The integration host factor (IHF) was found to be a necessity for the activation of transcription of the cobalamin biosynthetic (cob) and 1,2-propanediol (1,2-PDL) utilization (pdu) operons in Salmonella typhimurium LT2. The level of the regulatory protein PocR decreased in mutants which lack IHF. Also, even with PocR, in the absence of IHF, PocR failed to activate transcription of cob/pdu in response to 1,2-PDL. more...

The PocR protein of Salmonella typhimurium LT2 was overexpressed and used to demonstrate in vitro that it specifically binds to the cobalamin biosynthetic operon (cob) promoter region. PocR DNA-binding activity in vitro was found to be controlled by the effector molecule 1,2-propanediol. Two regions upstream of the promoter are required for optimal activation of P(sub cob) by PocR in vivo. PocR binds to two sites within P(sub cob). more...

Glutathione is necessary for the full expression of the cobalamin biosynthetic and 1,2-propanediol (1,2-PDL) utilization (cob/pdu) regulon and for the break down of 1,2-PDL, propionate, and ethanolamine in Salmonella (S.) typhimurium LT2. Researchers analyzed the DNA, nutritional requirements, and transcription patterns of a strain of S. typhimurium that does not fully express the cob more...

The cobIII region of the Salmonella typhimurium cobalamin (cob) operon codes for the nucleotide loop of cobalamin. Genetic and biochemical analyses were conducted on the cobIII region, which showed that the cobalamin biosynthetic region contains sequences coding for cobU and cobS, which codes for adenosyl-cobinamide kinase-GTP:adenosyl-cobinamide phosphate guanylyltransferase and cobalamin synthase, respectively. However, under the influence of the T7 promoter, three gene products were detected. more...

Cobalamin is required for the catabolism of 1,2- propanediol (1,2-PDL) as a carbon and energy source of Salmonella typhimurium. The operon needed to produce cobalamin, cob, is downstream from the genes that utilize 1,2-PDL, pdu. It was shown that a mutated locus, poc, results in unresponsiveness of cob to 1,2-PDL. The results indicate that 1,2-PDL is an activator of cob transcription. The expression of the cob and pdu operons is coregulated at the transcriptional level by the poc gene products in response to 1,2-PDL. more...

The cloning and sequence analysis of the Capreomycin (CMN) biosynthetic gene cluster from Saccharothrix mutabilis subsp. capreolus ATCC 23892 is discussed. Results suggest that the transfer of gene cluster into S. lividans 1326 leads to heterologous production of the CMN antituberculosis drug more...

Presents a study on the DNA polymerase I function as a requirement for the utilization of ethanolamine, 1,2-propanediol, and propionate by `Salmonella typhimurium' LT2. Materials and methods; Results and discussion; Acknowledgments; References. more...