The germ-soma distinction is a defining feature of multicellular eukaryotes. Analogous to this, ciliates, a ubiquitous microbial eukaryote lineage, have morphologically and functionally distinct nuclei, but within single cells: the germline micronucleus (MIC) and somatic macronucleus (MAC). The origins and mechanisms of the MIC to MAC transformation, especially the extensive elimination of abundant internally eliminated sequences (IESs) and transposons during genome reorganization, are great biological mysteries. Blepharisma represents one of the two earliest diverging ciliate classes, and has unique, dual pathways of MAC development, making it ideal for investigating the functioning, origins and evolution of these processes. Here, we report the MAC genome assembly of Blepharisma stoltei strain ATCC 30299 (41 Mb), arranged as numerous alternative telomere-capped minichromosomes, tens to hundreds of kilobases long. The B. stoltei MAC genome encodes eight PiggyBac transposase homologs liberated from transposons. All are subject to purifying selection, but just one, the putative Blepharisma IES excisase, has a complete catalytic amino acid triad. Numerous genes encoding other domesticated transposases are present in B. stoltei, and often are comparably strongly upregulated in a similar timeframe to model ciliate genome reorganization homologs. Our phylogenetic investigations suggest the PiggyBac homologs may have been ancestral ciliate IES excisases. The B. stoltei MAC genome, together with the upcoming MIC genome, highlights the evolution and complex interplay between transposons, domesticated transposases, and genome reorganization in the context of germline-soma differentiation within single cells.

The discovery of a series of thiophenephenyl­sulfonamides as positive allosteric modulators (PAM) of α7 nicotinic acetylcholine receptor (α7 nAChR) is described. Optimization of this series led to identification of compound 28, a novel PAM of α7 nicotinic acetylcholine receptor (α7 nAChR). Compound 28 showed good in vitro potency, with pharmacokinetic profile across species with excellent brain penetration and residence time. Compound 28 robustly reversed the cognitive deficits in episodic/working memory in both time-delay and scopolamine-induced amnesia paradigms in the novel object and social recognition tasks, at very low dose levels. Additionally, compound 28 has shown excellent safety profile in phase 1 clinical trials and is being evaluated for efficacy and safety as monotherapy in patients with mild to moderate Alzheimer’s disease.

We have amplified DNA from Mycobacterium tuberculosis on a paper substrate in 10 minutes using helicase dependent amplification technique.

During their development following sexual conjugation, ciliates excise numerous internal eliminated sequences (IESs) from a copy of the germline genome to produce the functional somatic genome. Most IESs are thought to have originated from transposons, but the presumed homology is often obscured by sequence decay. To obtain more representative perspectives on the nature of IESs and ciliate genome editing, we assembled 40,000 IESs of Blepharisma stoltei , a species belonging to a lineage (Heterotrichea) that diverged early from those of the intensively studied model ciliate species. About a quarter of IESs were short (<115 bp), largely nonrepetitive, and with a pronounced ~10 bp periodicity in length; the remainder were longer (up to 7 kbp) and nonperiodic and contained abundant interspersed repeats. Contrary to the expectation from current models, the assembled Blepharisma germline genome encodes few transposases. Instead, its most abundant repeat (8,000 copies) is a Miniature Inverted-repeat Transposable Element (MITE), apparently a deletion derivative of a germline-limited Pogo-family transposon. We hypothesize that MITEs are an important source of IESs whose proliferation is eventually self-limiting and that rather than defending the germline genomes against mobile elements, transposase domestication actually facilitates the accumulation of junk DNA.