The Determination of Nucleic Acids

Clustered regularly interspaced short palindromic repeats (CRISPR)-encoded immunity in Type I systems relies on the Cascade (CRISPR-associated complex for antiviral defence) ribonucleoprotein complex, which triggers foreign DNA degradation by an accessory Cas3 protein. To establish the mechanism for adaptive immunity provided by the Streptococcus thermophilus CRISPR4-Cas (CRISPR-associated) system (St-CRISPR4-Cas), we isolated an effector complex (St-Cascade) containing 61-nucleotide CRISPR RNA (crRNA). We show that St-Cascade, guided by crRNA, binds in vitro to a matching proto-spacer if a proto-spacer adjacent motif (PAM) is present. Surprisingly, the PAM sequence determined from binding analysis is promiscuous and limited to a single nucleotide (A or T) immediately upstream (-1 position) of the proto-spacer. In the presence of a correct PAM, St-Cascade binding to the target DNA generates an R-loop that serves as a landing site for the Cas3 ATPase/nuclease. We show that Cas3 binding to the displaced strand in the R-loop triggers DNA cleavage, and if ATP is present, Cas3 further degrades DNA in a unidirectional manner. These findings establish a molecular basis for CRISPR immunity in St-CRISPR4-Cas and other Type I systems.

/pdf/in-vitro-reconstitution-of-cascade-mediated-crispr-immunity-yfb3pp4x22.pdf

In vitro reconstitution of Cascade‐mediated CRISPR immunity in Streptococcus thermophilus

Rapid colorimetric methods for the determination of phosphorus in urine and blood

This chapter describes the dynamics of dissolved organic phosphorus (DOP). Phosphorus (P) is an essential macronutrient for all living organisms; life is truly built around P. In the sea, P exists in both dissolved and particulate pools with inorganic and organic forms. The uptake, re-mineralization, and physical and biological exchanges among these various pools are the essential components of the marine P cycle. Compared to the much more comprehensive investigations of carbon (C) and nitrogen (N) dynamics in the sea, P pool inventories and fluxes are less well documented though no less important. During cell growth, P is incorporated into a broad spectrum of organic compounds with vital functions including structure, metabolism, and regulation. When cells turn over (by death/autolysins, grazing, parasitism, or viral infection), there is an enhanced release of intracellular P-containing compounds as both dissolved and particulate organic matter.

Chapter 6 – Dynamics of DOP

Regulation of respiration in plants: a role for alternative metabolic pathways.

The occurrence of plant nucleotides in animal tissues

On the identity of the nucleic acids of the thymus, spleen and pancreas

http://www.jbc.org/content/3/1/1.full.pdf

On thymus nucleic acid

The admissibility of ammonium magnesium phosphate as a form in which to weigh phosphoric acid

Über die bei der Spaltung der Nucleine in Betracht kommenden Fermente mit besonderer Berücksichtigung der Bildung von Hypoxanthin in der Abwesenheit von Adenase.

Walter Jones

Papers

The occurrence of plant nucleotides in animal tissues

On the identity of the nucleic acids of the thymus, spleen and pancreas

On thymus nucleic acid

The admissibility of ammonium magnesium phosphate as a form in which to weigh phosphoric acid

Über die bei der Spaltung der Nucleine in Betracht kommenden Fermente mit besonderer Berücksichtigung der Bildung von Hypoxanthin in der Abwesenheit von Adenase.