A phage-encoded anti-activator inhibits quorum sensing in Pseudomonas aeruginosa.

The arms race between bacteria and phages has led to the evolution of diverse anti-phage defenses, several of which are controlled by quorum-sensing pathways. In this work, we characterize a quorum-sensing anti-activator protein, Aqs1, found in Pseudomonas phage DMS3. We show that Aqs1 inhibits LasR, the master regulator of quorum sensing, and present the crystal structure of the Aqs1-LasR complex.

Anti-CRISPRs: Protein Inhibitors of CRISPR-Cas Systems.

Clustered regularly interspaced short palindromic repeats (CRISPR) together with their accompanying (CRISPR-associated) genes are found frequently in bacteria and archaea, serving to defend against invading foreign DNA, such as viral genomes. CRISPR-Cas systems provide a uniquely powerful defense because they can adapt to newly encountered genomes. The adaptive ability of these systems has been exploited, leading to their development as highly effective tools for genome editing.

Anti-CRISPR AcrIIA5 Potently Inhibits All Cas9 Homologs Used for Genome Editing.

CRISPR-Cas9 systems provide powerful tools for genome editing. However, optimal employment of this technology will require control of Cas9 activity so that the timing, tissue specificity, and accuracy of editing may be precisely modulated. Anti-CRISPR proteins, which are small, naturally occurring inhibitors of CRISPR-Cas systems, are well suited for this purpose.

Anti-CRISPR-Associated Proteins Are Crucial Repressors of Anti-CRISPR Transcription.

Phages express anti-CRISPR (Acr) proteins to inhibit CRISPR-Cas systems that would otherwise destroy their genomes. Most acr genes are located adjacent to anti-CRISPR-associated (aca) genes, which encode proteins with a helix-turn-helix DNA-binding motif. The conservation of aca genes has served as a signpost for the identification of acr genes, but the function of the proteins encoded by these genes has not been investigated.

Phage-Encoded Anti-CRISPR Defenses.

The battle for survival between bacteria and bacteriophages (phages) is an arms race where bacteria develop defenses to protect themselves from phages and phages evolve counterstrategies to bypass these defenses. CRISPR-Cas adaptive immune systems represent a widespread mechanism by which bacteria protect themselves from phage infection. In response to CRISPR-Cas, phages have evolved protein inhibitors known as anti-CRISPRs.

Massive CAG repeat expansion and somatic instability in maternally transmitted infantile spinocerebellar ataxia type 7.

Importance: We report the first case to date of maternally transmitted infantile spinocerebellar ataxia type 7 (SCA7), in which a tract of (CAG)45 expands to lengths as large as (CAG)92-250.

Observations: A 38-year-old woman with classic SCA7 (and a son, who died at age 3 years) had pronounced cerebellar atrophy and a renal biopsy specimen that showed focal segmental glomerulosclerosis with abnormal podocytes containing cytoplasmic inclusions. Polymerase chain reaction amplification across the SCA7 repeat tract assessed expansion levels in tissues of the affected son.

The disease-associated r(GGGGCC)n repeat from the C9orf72 gene forms tract length-dependent uni- and multimolecular RNA G-quadruplex structures.

Certain DNA and RNA sequences can form G-quadruplexes, which can affect promoter activity, genetic instability, RNA splicing, translation, and neurite mRNA localization. Amyotrophic lateral sclerosis and frontotemporal dementia were recently shown to be caused by expansion of a (GGGGCC)n·(GGCCCC)n repeat in the C9orf72 gene. Mutant r(GGGGCC)n-containing transcripts aggregate in nuclear foci possibly sequestering repeat-binding proteins, suggesting a toxic RNA pathogenesis.

A clip-free eyeglasses-based wearable monitoring device for measuring photoplethysmograhic signals.

An eyeglasses-based device has been developed in this work to acquire photoplethysmogram (PPG) from the nose bridge. This device is aimed to provide wearable physiological monitoring without uncomfortable clips frequently used in PPG measurement from finger and ear. Switching control is applied on the LED and photo detector for power saving.

Terahertz pulsed imaging in vivo: measurements and processing methods.

This paper presents a number of data processing algorithms developed to improve the accuracy of results derived from datasets acquired by a recently designed terahertz handheld probe. These techniques include a baseline subtraction algorithm and a number of algorithms to extract the sample impulse response: double Gaussian inverse filtering, frequency-wavelet domain deconvolution, and sparse deconvolution. In vivo measurements of human skin are used as examples, and a comparison is made of the terahertz impulse response from a number of different skin positions.

Terahertz spectroscopy of liver cirrhosis: investigating the origin of contrast.

We have previously demonstrated that terahertz pulsed imaging is able to distinguish between rat tissues from different healthy organs. In this paper we report our measurements of healthy and cirrhotic liver tissues using terahertz reflection spectroscopy. The water content of the fresh tissue samples was also measured in order to investigate the correlations between the terahertz properties, water content, structural changes and cirrhosis.