Progress in both molecular techniques and phylogenetic methods has challenged many of the interpretations of traditional taxonomy. One example is in the recognition of the animal superphylum Lophotrochozoa (annelids, mollusks, echiurans, platyhelminthes, brachiopods, and other phyla), although the relationships within this group and the inclusion of some phyla remain uncertain. While much of this progress… [Read More]

We describe a targeted approach to improve the contiguity of whole-genome shotgun sequence (WGS) assemblies at run-time, using information from Bacterial Artificial Chromosome (BAC)-based physical maps. Clone sizes and overlaps derived from clone fingerprints are used for the calculation of length constraints between any two BAC neighbors sharing 40% of their size. These constraints are… [Read More]

Nitrosomonas europaea, as an ammonia-oxidizing bacterium, has a high Fe requirement and has 90 genes dedicated to Fe acquisition. Under Fe-limiting conditions (0.2 mu M Fe), N. europaea was able to assimilate up to 70% of the available Fe in the medium even though it is unable to produce siderophores. Addition of exogenous siderophores to… [Read More]

Ecologists studying microbial life in the environment have recognized the enormous complexity of microbial diversity for many years, and the development of a variety of culture-independent methods, many of them coupled with high-throughput DNA sequencing, has allowed this diversity to be explored in ever-greater detail. Despite the widespread application of these new techniques to the… [Read More]

Sequencing of the large (> 50 kb), low-copy-number (< 5 per cell) plasmids that mediate horizontal gene transfer has been hindered by the difficulty and expense of isolating DNA from individual plasmids of this class. We report here that a kit method previously devised for purification of bacterial artificial chromosomes (BACs) can be adapted for... [Read More]

Symbioses between bacteria and eukaryotes are ubiquitous, yet our understanding of the interactions driving these associations is hampered by our inability to cultivate most host-associated microbes. Here we use a metagenomic approach to describe four co-occurring symbionts from the marine oligochaete Olavius algarvensis, a worm lacking a mouth, gut and nephridia. Shotgun sequencing and metabolic… [Read More]

Genome sequencing currently requires DNA from pools of numerous nearly identical cells (clones), leaving the genome sequences of many difficult-to-culture microorganisms unattainable. We report a sequencing strategy that eliminates culturing of microorganisms by using real-time isothermal amplification to form polymerase clones (plones) from the DNA of single cells. Two Escherichia coli plones, analyzed by Affymetrix… [Read More]