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Edited by Renee TsolisLeptospira interrogans serovar Copenhageni strain Fiocruz L1-130 carries a set of cas genes associated with CRISPR-Cas subtype I-B. Herein, we report for the first time active transcription of a set of cas genes (cas1 to cas8) of L. interrogans where cas4, cas1, cas2 and cas6, cas3, cas8, cas7, cas5 are clustered together in two independent operons. As an initial step toward comprehensive understanding of CRISPR-Cas system in spirochete, the biochemical study of one of the core Leptospira Cas2 proteins (Lep_Cas2) showed nuclease activity on both DNA and RNA in a nonspecific manner. Additionally, unlike other known Cas2 proteins, Lep_Cas2 showed metal-independent RNase activity and preferential activity on RNA over DNA. These results provide insight for understanding Cas2 diversity existing in the prokaryotic adaptive immune system.

Almost all eukaryotic proteins are subject to post-translational modifications during mitosis and cell cycle, and in particular, reversible phosphorylation being a key event. The recent use of high-throughput experimental analyses has revealed that more than 70% of all eukaryotic proteins are regulated by phosphorylation; however, the mechanism of dephosphorylation, counteracting phosphorylation, is relatively unknown. Recent discoveries have shown that many of the protein phosphatases are involved in the temporal and spatial control of mitotic events, such as mitotic entry, mitotic spindle assembly, chromosome architecture changes and cohesion, and mitotic exit. This implies that certain phosphatases are tightly regulated for timely dephosphorylation of key mitotic phosphoproteins and are essential for control of various mitotic processes. This review describes the physiological and pathological roles of mitotic phosphatases, as well as the versatile role of various protein phosphatases in several mitotic events.

Several comprehensive User Centred Design methodologies have been published in the last decade, but while they all focus on users, they disagree on exactly what activities should take place during the User Needs Analysis, what the end products of a User Needs Analysis should cover, how User Needs Analysis findings should be presented, and how these should be documented and communicated. This paper highlights issues in different stages of the User Needs Analysis that appear to cause considerable confusion among researchers and practitioners. It is our hope that the User-Centred Design community may begin to address these issues systematically. A case study is presented reporting a User Needs Analysis methodology and process as well as the user interface design of an application supporting communication among first responders in a major disaster. It illustrates some of the differences between the User-Centred Design and the Requirements Engineering communities and shows how and where User-Centred Design and Requirements Engineering methodologies should be integrated, or at least aligned, to avoid some of the problems practitioners face during the User Needs Analysis. q

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The application of usability techniques to the development of music-related hardware is rarely discussed in the HCI literature. This is in spite of the fact that such devices could potentially be improved by employing usability methods during their development. This paper documents a case study of an existing electric guitar pre-amplifier. The ease of use of its user interface was investigated using the traditional HCI methods of heuristic evaluation and usability testing. The user interface was subsequently modified, and a follow-up usability test confirmed improvements to ease of use. These findings demonstrate that HCI methods can and should be used to enhance the usability of music-related hardware.

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