title: Ribonucleases in bacterial toxin–antitoxin systems

authors: Cook, Gregory M.

subjects: Endoribonucleases

abstract: Toxin-antitoxin (TA) systems are widespread in bacteria and archaea and play important roles in a diverse range of cellular activities. TA systems have been broadly classified into 5 types and the targets of the toxins are diverse, but the most frequently used cellular target is mRNA. Toxins that target mRNA to inhibit translation can be classified as ribosome-dependent or ribosome-independent RNA interferases. These RNA interferases are sequence-specific endoribonucleases that cleave RNA at specific sequences. Despite limited sequence similarity, ribosome-independent RNA interferases belong to a limited number of structural classes. The MazF structural family includes MazF, Kid, ParE and CcdB toxins. MazF members cleave mRNA at 3-, 5- or 7-base recognition sequences in different bacteria and have been implicated in controlling cell death (programmed) and cell growth, and cellular responses to nutrient starvation, antibiotics, heat and oxidative stress. VapC endoribonucleases belong to the PIN-domain family and inhibit translation by either cleaving tRNAfMet in the anticodon stem loop, cleaving mRNA at -AUA(U/A)-hairpin-G- sequences or by sequence-specific RNA binding. VapC has been implicated in controlling bacterial growth in the intracellular environment and in microbial adaptation to nutrient limitation (nitrogen, carbon) and heat shock. ToxN shows structural homology to MazF and is also a sequence-specific endoribonuclease. ToxN confers phage resistance by causing cell death upon phage infection by cleaving cellular and phage RNAs, thereby interfering with bacterial and phage growth. Notwithstanding our recent progress in understanding ribonuclease action and function in TA systems, the environmental triggers that cause release of the toxin from its cognate antitoxin and the precise cellular function of these systems in many bacteria remain to be discovered. This article is part of a Special Issue entitled: RNA Decay mechanisms.

text: Ribonucleases in bacterial toxin–antitoxin systems Toxin-antitoxin (TA) systems are widespread in bacteria and archaea and play important roles in a diverse range of cellular activities. TA systems have been broadly classified into 5 types and the targets of the toxins are diverse, but the most frequently used cellular target is mRNA. Toxins that target mRNA to inhibit translation can be classified as ribosome-dependent or ribosome-independent RNA interferases. These RNA interferases are sequence-specific endoribonucleases that cleave RNA at specific sequences. Despite limited sequence similarity, ribosome-independent RNA interferases belong to a limited number of structural classes. The MazF structural family includes MazF, Kid, ParE and CcdB toxins. MazF members cleave mRNA at 3-, 5- or 7-base recognition sequences in different bacteria and have been implicated in controlling cell death (programmed) and cell growth, and cellular responses to nutrient starvation, antibiotics, heat and oxidative stress. VapC endoribonucleases belong to the PIN-domain family and inhibit translation by either cleaving tRNAfMet in the anticodon stem loop, cleaving mRNA at -AUA(U/A)-hairpin-G- sequences or by sequence-specific RNA binding. VapC has been implicated in controlling bacterial growth in the intracellular environment and in microbial adaptation to nutrient limitation (nitrogen, carbon) and heat shock. ToxN shows structural homology to MazF and is also a sequence-specific endoribonuclease. ToxN confers phage resistance by causing cell death upon phage infection by cleaving cellular and phage RNAs, thereby interfering with bacterial and phage growth. Notwithstanding our recent progress in understanding ribonuclease action and function in TA systems, the environmental triggers that cause release of the toxin from its cognate antitoxin and the precise cellular function of these systems in many bacteria remain to be discovered. This article is part of a Special Issue entitled: RNA Decay mechanisms.

year: 2013

title: Accurate low-cost expanded-scale analog voltmeter with novel charge/discharge indication for monitoring single Lithium-ion cells

authors: Scott, Jonathan B.

abstract: This manuscript presents a very low-cost circuit using a PIC12F683 microcontroller and an LM285 bandgap voltage reference that provides an expanded-scale to an analog panel meter suitable for monitoring a single Lithium-ion battery. Charge or discharge of the cell is indicated by periodic twitches of the needle to the left or the right. The design is especially suitable for small devices subject to intermittant use or that recharge by power-harvesting. The design is open-source, with circuit, board layout, and source code provided.

text: Accurate low-cost expanded-scale analog voltmeter with novel charge/discharge indication for monitoring single Lithium-ion cells This manuscript presents a very low-cost circuit using a PIC12F683 microcontroller and an LM285 bandgap voltage reference that provides an expanded-scale to an analog panel meter suitable for monitoring a single Lithium-ion battery. Charge or discharge of the cell is indicated by periodic twitches of the needle to the left or the right. The design is especially suitable for small devices subject to intermittant use or that recharge by power-harvesting. The design is open-source, with circuit, board layout, and source code provided.

year: 2016

title: Prototype theory and the concept of taonga: Implications for Treaty-related issues such as the display and conservation of taonga Māori

authors: Hedley, Rangiiria

subjects: Taonga Māori

abstract: This paper examines, in the context of prototype theory, issues and problems associated with the concept of taonga, the specific aim being to provide an approach that could assist those who are concerned with the interpretation of Article 2 of the Treaty of Waitangi and Treaty-related issues such as the appropriate display and conservation of taonga Māori.

text: Prototype theory and the concept of taonga: Implications for Treaty-related issues such as the display and conservation of taonga Māori This paper examines, in the context of prototype theory, issues and problems associated with the concept of taonga, the specific aim being to provide an approach that could assist those who are concerned with the interpretation of Article 2 of the Treaty of Waitangi and Treaty-related issues such as the appropriate display and conservation of taonga Māori.

year: 2004-02