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A polynucleotide kinase from the thermophilic bacteriophage RM378 that infects the thermophilic eubacterium Rhodothermus marinus was identified, expressed, and purified. This polynucleotide kinase was demonstrated to have a 5'-kinase domain as well as a 3'-phosphohydrolase domain. The RM378 polynucleotide kinase had limited sequence similarity to the 5'-kinase domain of the T4 bacteriophage polynucleotide kinase, but apparent homology was not evident within the 3'-phosphohydrolase domain. The domain order of RM378 polynucleotide kinase was reversed relative to that of the T4 polynucleotide kinase. The RM378 phosphohydrolase domain displayed some sequence similarity with the bacterial poly(A) polymerase family, including an HD motif characteristic of the diverse superfamily of metal-dependent HD phosphohydrolases. The RM378 polynucleotide kinase was biochemically characterized and shown to possess 5'-kinase activity on RNA and single- and double-stranded DNA at elevated temperatures. It also showed phosphohydrolase activity on 2':3'-cyclic adenosine monophosphate. This description of the RM378 polynucleotide kinase, along with the recently described RM378 RNA ligase, suggests that the RM378 bacteriophage has to counter a similar anti-phage mechanism in R. marinus as the one that the T4 phage has to counter in Escherichia coli.

We have recently sequenced the genome of a novel thermophilic bacteriophage designated as TS2126 that infects the thermophilic eubacterium Thermus scotoductus. One of the annotated open reading frames (ORFs) shows homology to T4 RNA ligase 1, an enzyme of great importance in molecular biology, owing to its ability to ligate single-stranded nucleic acids. The ORF was cloned, and recombinant protein was expressed, purified and characterized. The recombinant enzyme ligates single-stranded nucleic acids in an ATP-dependent manner and is moderately thermostable. The recombinant enzyme exhibits extremely high activity and high ligation efficiency. It can be used for various molecular biology applications including RNA ligase-mediated rapid amplification of cDNA ends (RLM-RACE). The TS2126 RNA ligase catalyzed both inter- and intra-molecular single-stranded DNA ligation to >50% completion in a matter of hours at an elevated temperature, although favoring intra-molecular ligation on RNA and single-stranded DNA substrates. The properties of TS2126 RNA ligase 1 makes it very attractive for processes like adaptor ligation, and single-stranded solid phase gene synthesis.

Functional magnetic resonance imaging (fMRI) provides high-resolution, non-invasive estimates of neural activity detected by a blood oxygen level dependent signal by assessing the increase in blood flow to the local vasculature that accompanies neural activity in the brain. fMRI studies with standard hand motor test (index-thumb opposition, ITO, or pinch) in ALS patients show good test-retest reliability and similar amplitude of signals in ALS patients compared with control subjects. Isometric force can be performed with careful control for the force exerted, recruitment of other muscles and motion artefact. The volume (number of voxels above threshold) of sensorimotor and cerebellar cortex activated by ITO is reproducibly larger in ALS patients compared with control subjects. Imagined movements in ALS have been studied, as in amputees, and larger volumes are activated in ALS patients with imagined movements as well, compared with control subjects. fMRI studies in ALS patients evaluating cortical activation during pure somatosensory stimulation cutaneous stimulation of the hand to elicit the palmomental response and cutaneous stimulation of the sole to elicit the plantar response - indicate that ALS patients activate a significantly smaller volume of the contralateral sensorimotor cortex compared to control subjects. No statistically significant difference was seen in other areas, including the ipsilateral cerebellum and the contralateral thalamus. An anterior shift in the volume of cortex activated by these paradigms occurs in ALS patients, with a volume of activation, anteriorly, not activated in control subjects. fMRI studies will complement other clinical neurophysiological and neuroimaging techniques in our future attempts to solve the riddle of ALS and other motor neuron diseases.