Escherichia coli RecBCD is a DNA helicase/nuclease that functions in double-stranded DNA break repair. RecBCD possesses two motors (RecB, a 3′ to 5′ translocase, and RecD, a 5′ to 3′ translocase). Current DNA unwinding models propose that motor translocation is tightly coupled to base pair (bp) melting. However, some biochemical evidence suggests that DNA melting of multiple bp may occur separately from single stranded DNA translocation. To test this hypothesis, we designed DNA substrates containing reverse backbone polarity (RP) linkages that prevent ssDNA translocation of the canonical RecB and RecD motors. Surprisingly, we find that RecBCD can processively unwind DNA for at least 80 bp beyond the RP linkages. This ability requires an ATPase active RecB motor, the RecB “arm” domain and also the RecB nuclease domain, but not its nuclease activity. These results indicate that RecBCD can unwind duplex DNA processively in the absence of ssDNA translocation by the canonical motors and that the nuclease domain regulates the helicase activity of RecBCD.
The utility of the Test of Memory Malingering (TOMM) with mentally retarded forensic patients was assessed. Twenty-one adjudicated forensic inpatients, who had been diagnosed with mental retardation, were administered the TOMM. The majority of these patients also suffered from an Axis I mental disorder. The participants attained a mean score of 48.7 on Trial 2, with only 1 participant scoring below the standard cutoff for malingering (i.e., 45). The participants attained a mean score of 49.4 on the Retention Trial, with no participants falling below the cutoff for malingering. The results clearly indicate that mildly retarded forensic patients can perform well on the TOMM. The findings provide evidence that the TOMM can be used in the assessment of mildly retarded criminal defendants with little fear of obtaining false indications of malingering.
An attempt was made to evaluate the utility of the Rey Memory Test (Rey, 1964) to assess malingering in criminal defendants referred for inpatient forensic evaluation. The performance of 14 diagnosed malingerers was compared to a control group of 14 forensic inpatients who had been acquitted by reason of insanity. Malingerers performed significantly less well on the test than did controls. A previously suggested cut‐off score of 9 items remembered (Lezak, 1983) resulted in correct classification of 86% of the subjects as either malingering or not malingering. However, a cut‐off of 3 rows remembered correctly was found to be inappropriate because 57% of the controls would have been labeled incorrectly as malingerers.
Background:The ribose transporter is a bacterial ABC importer with a non-canonical organization. Results: The binding protein complexes with the membrane domain in the absence of substrate, and the ATPase dissociates from the membrane domain during transport. Conclusion: A distinct model for transport is proposed from in vitro reassembly conditions and EPR data. Significance: The ribose transporter typifies the diversity of ABC transporter mechanisms.
Quick Test and WAIS-R scores of 30 low-functioning criminal defendants were compared. Analysis indicated that the Quick Test (even 1 form) genetically provides an accurate estimate of WAIS-R IQ in this population.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.