c-fos Gene Expression in Postnatal Rat Retinas with Light/Dark Cycle

AbstractWe examined the diurnal variation of c-fos gene expression during a 12:12 light/dark cycle in developing rat retinas by in situ hybridization histochemistry. c-fos Gene was not expressed before postnatal day 10 (P10) but was expressed on P15 in the outer nuclear layer throughout the dark period and in the inner nuclear layer and the ganglion cell layer during the light period. These results demonstrated that the earliest c-fos gene expression occurred between P11 and P15. The good correlation between the expression of c-fos gene and the genes coding for proteins involved in phototransduction, in terms of their diurnal variation and in their development, suggested that c-fos gene may play a role in the regulation of these genes in retinal cells during the light/dark cycle. Copyright © 1996 Elsevier Science Ltd

Identification and Characterization of a Novel Multidrug Resistance Operon, mdtRP (yusOP), of Bacillus subtilis▿

Using comparative genome sequencing analysis, we identified a novel mutation in Bacillus subtilis that confers a low level of resistance to fusidic acid. This mutation was located in the mdtR (formerly yusO) gene, which encodes a MarR-type transcriptional regulator, and conferred a low level of resistance to several antibiotics, including novobiocin, streptomycin, and actinomycin D. Transformation experiments showed that this mdtR mutation was responsible for multidrug resistance. Northern blot analysis revealed that the downstream gene mdtP (formerly yusP), which encodes a multidrug efflux transporter, is cotranscribed with mdtR as an operon. Disruption of the mdtP gene completely abolished the multidrug resistance phenotype observed in the mdtR mutant. DNase I footprinting and primer extension analyses demonstrated that the MdtR protein binds directly to the mdtRP promoter, thus leading to repression of its transcription. Moreover, gel mobility shift analysis indicated that an Arg83 → Lys or Ala67 → Thr substitution in MdtR significantly reduces binding affinity to DNA, resulting in derepression of mdtRP transcription. Low concentrations of fusidic acid induced the expression of mdtP, although the level of mdtP expression was much lower than that in the mdtR disruptant. These findings indicate that the MdtR protein is a repressor of the mdtRP operon and that the MdtP protein functions as a multidrug efflux transporter in B. subtilis

Hand Dexterity Impairment in Patients with Cervical Myelopathy: A New Quantitative Assessment Using a Natural Prehension Movement

Cervical myelopathy (CM) caused by spinal cord compression can lead to reduced hand dexterity. However, except for the 10 sec grip-and-release test, there is no objective assessment system for hand dexterity in patients with CM. Therefore, we evaluated the hand dexterity impairment of patients with CM objectively by asking them to perform a natural prehension movement. Twenty-three patients with CM and 30 age-matched controls were asked to reach for and grasp a small object with their right thumb and index finger and to subsequently lift and hold it. To examine the effects of tactile afferents from the fingers, objects with surface materials of differing textures (silk, suede, and sandpaper) were used. All patients also underwent the Japanese Orthopedic Association (JOA) test. Preoperative patients showed significantly greater grip aperture during reach-to-grasp movements and weaker grip force than controls only while attempting to lift the most slippery object (silk). Patients, immediately after surgery, (n=15) tended to show improvements in the JOA score and in reaction time and movement time with respect to reaching movements. Multiple regression analysis demonstrated that some parameters of the prehension task could successfully predict subjective evaluations of dexterous hand movements based on JOA scores. These results suggest that quantitative assessments using prehension movements could be useful to objectively evaluate hand dexterity impairment in patients with CM

Hidden chemical order in disordered Ba7Nb4MoO20 revealed by resonant X-ray diffraction and solid-state NMR

Abstract The chemical order and disorder of solids have a decisive influence on the material properties. There are numerous materials exhibiting chemical order/disorder of atoms with similar X-ray atomic scattering factors and similar neutron scattering lengths. It is difficult to investigate such order/disorder hidden in the data obtained from conventional diffraction methods. Herein, we quantitatively determined the Mo/Nb order in the high ion conductor Ba7Nb4MoO20 by a technique combining resonant X-ray diffraction, solid-state nuclear magnetic resonance (NMR) and first-principle calculations. NMR provided direct evidence that Mo atoms occupy only the M2 site near the intrinsically oxygen-deficient ion-conducting layer. Resonant X-ray diffraction determined the occupancy factors of Mo atoms at the M2 and other sites to be 0.50 and 0.00, respectively. These findings provide a basis for the development of ion conductors. This combined technique would open a new avenue for in-depth investigation of the hidden chemical order/disorder in materials