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PubMed2003

Physical activity and functional status in community-dwelling older women: a 14-year prospective study.

BACKGROUND: Short-term prospective studies have shown physical activity to be related to functional status. To our knowledge, the association between physical activity levels and functional status over a longer period has not been established. METHODS: Two hundred twenty-nine older women (mean age, 74.2 years) who were involved in a randomized controlled walking intervention from 1982 to 1985 were subsequently followed up until December 1999. Physical activity was assessed in 1985, 1995, and 1999 using a physical activity questionnaire and a physical activity monitor. In 1999, functional status was assessed by self-report and performance-based measures. RESULTS: Subjective and objective measures of physical activity in 1985 independently predicted gait speed in 1999 after controlling for age, chronic conditions, and activity limitation (subjective model-adjusted R2 = 0.09 [P=.03]; and objective model-adjusted R2 = 0.13 [P=.008]). The consistency of physical activity participation from 1985 to 1995 was also related to functional status in 1999. Women who were always active had the best functional status and women who were always inactive had the worst functional status. For difficulty with activities of daily living: those always active, 17 (37.8%) of 45 women; those inconsistently active, 24 (40.0%) of 60 women; and those always inactive, 39 (59.1%) of 66 women (chi2 for trend P=.02). For score on the Physical Performance Test: those always active, 24.9; those inconsistently active, 24.5; and those always inactive, 23.8 (analysis of variance with linear contrasts P=.04). For gait speed: those always active, 1.17 m/s; those inconsistently active, 1.15 m/s; and those always inactive, 1.03 m/s (analysis of variance with linear contrasts P=.002). CONCLUSION: We demonstrated a significant relation between physical activity during a 14-year period and current functional status in older women, thus suggesting that physical activity plays a role in maintaining functional ability later in life.

Activities of Daily Living↗
PubMed2006

Self-guided brisk walking training with or without poles: a randomized-controlled trial in middle-aged women.

Walking with poles (Nordic walking, NW) has become popular. We compared training responses of brisk walking (W) or NW on cardiorespiratory and neuromuscular fitness. We randomized 121 non-obese sedentary women (aged 50-60) to an NW or W group (NWG, WG), to train 40 min four times weekly for 13 weeks. Intensity was based on subjective perception of exertion. Cardiorespiratory performance was assessed in four levels corresponding to 50%, 65%, 80% and 100% of peak VO(2). Fifty-four NWG and 53 WG subjects completed the study. The mean intensity was about 50% of heart rate (HR) reserve. The baseline peak VO(2) was 25.8 (SD 3.9) mL/min/kg. Both groups improved peak VO(2) similarly (NWG 2.5 mL/min/kg, 95% confidence interval (CI) 1.9-3.3; WG 2.6, CI 1.9-3.3). In the submaximal stages while walking with or without poles, HR and lactate decreased after training in both groups, but the changes were not statistically significantly different between the groups. Of the neuromuscular tests after training, the only significant difference between the groups was in the leg strength in the one-leg squat, favoring WG. In conclusion, both training modes improved similarly health-enhancing physical fitness, and they were feasible and safe.

Cross-Sectional Studies↗
PubMed2003

Wheeled and standard walkers in Parkinson's disease patients with gait freezing.

OBJECTIVES: Compare the efficacy of two walking assistance devices (wheeled walker and standard walker) to unassisted walking for patients with PD and gait freezing. BACKGROUND: Although numerous walking devices are used clinically, their relative effects on freezing and walking speed have never been systematically tested. METHODS: Nineteen PD patients (14 non-demented) walked under three conditions in randomized order: unassisted walking, standard walker, and wheeled walker. Patients walked up to three times in each condition through a standard course that included rising from a chair, walking through a doorway, straightway walking, pivoting, and return. Total walking time, freezing time and number of freezes were compared for the three conditions using mixed models (walking time) and Friedman's test (freezing). The wheeled walker was further studied by comparing the effect of an attached laser that projected a bar of light on the floor as a visual walking cue. RESULTS: Use of either type of device significantly slowed walking compared to unassisted walking. Neither walker reduced any index of freezing, nor the laser attachment offered any advantage to the wheeled walker. The standard walker increased freezing, and the wheeled walker had no effect on freezing. Among the non-demented subjects (n=14), the same patterns occurred, although the walking speed was less impaired by the wheeled walker than the standard walker in this group. CONCLUSIONS: Though walkers may stabilize patients and increase confidence, PD patients walk more slowly when using them, without reducing freezing. Because the wheeled walker was intermediate for walking time and does not aggravate freezing, if walkers are used for these subjects, this type of walker should be favored.

Aged↗
PubMed1998

A comparison of two physiotherapy treatment approaches to improve walking in multiple sclerosis: a pilot randomized controlled study.

OBJECTIVE: To use a pilot study to compare two physiotherapy approaches to improve walking in patients with gait disturbance due to multiple sclerosis (MS). DESIGN: Patients were assessed and then randomly assigned to one of two groups using a block randomization technique. They were treated by the research physiotherapist for a minimum of 15 treatments over a 5-7-week period and then reassessed by an independent therapist one week after treatment. SETTING: Both assessment and treatment were undertaken at a specialist rehabilitation centre. SUBJECTS: Outpatients with clinically stable MS (chronic progressive or relapsing-remitting types) who were referred for physiotherapy to improve their mobility. INTERVENTION: Comparison was between a facilitation (impairment-based) approach and a task-oriented (disability-focused) approach. OUTCOME: Mobility was assessed using four measures: the 10-metre timed walk, the Rivermead Mobility Index, stride length and the Rivermead Visual Gait Assessment. Balance was assessed using the Berg Balance Test. RESULTS: Twenty-three patients were entered, and 10 in each group completed the study. The groups were similar on all measured items both before and after treatment. There was no significant difference in improvement between the two approaches. Following treatment, patients in both groups showed a significant overall improvement (p < 0.05) in both impairment and disability measures. CONCLUSIONS: No significant differences in effectiveness between the two methods were demonstrated. Both a task-oriented approach and a facilitation approach to the treatment of MS outpatients were associated with improved mobility.

Disability Evaluation↗
PubMed2000

Adaptive walks by the fittest among finite random mutants on a Mt. Fuji-type fitness landscape. II. Effect of small non-additivity.

We examined properties of adaptive walks by the fittest on "rough Mt. Fuji-type" fitness landscapes, which are modeled by superposing small uncorrelated random component on an additive fitness landscape. A single adaptive walk is carried out by repetition of the evolution cycle composed of (1) mutagenesis process that produces random d-fold point mutants of population size N and (2) selection process that picks out the fittest mutant among them. To comprehend trajectories of the walkers, the fitness landscape is mapped into a (x, y, z)-space, where x, y and z represent, respectively, normalized Hamming distance from the peak on the additive fitness landscape, scaled additive fitness and scaled nonadditive fitness. Thus a single adaptive walk is expressed as the dynamics of a particle in this space. We drew the "hill-climbing" vector field, where each vector represents the most probable step for a walker in a single step. Almost all of the walkers are expected to move along streams of vectors existing on a particular surface that overlies the (x, y)-plane, toward the neighborhood of a characteristic point at which a mutation-selection-random drift balance is reached. We could theoretically predict this reachable point in the case of random sampling search strategy.

Biological Evolution↗
PubMed2005

Brisk walking, fitness, and cardiovascular risk: a randomized controlled trial in primary care.

STUDY OBJECTIVE: To examine the effects of 30 min of self-paced, non-supervised, brisk walking, 5 days per week on the health and fitness of people aged 50-65 years. DESIGN: Randomized controlled trial. Members of the intervention group (n = 21) were directed to walk briskly for 30 min, 5 days per week, for 12 weeks. Individuals were given the choice to complete the 30 min of walking in one session or in shorter bouts of no less than 10 min. They were asked to record in a diary the time spent walking and the number of steps taken during a single walk using a pedometer. Participants in the control group (n = 10) were asked to maintain their habitual lifestyle and not change their activity or dietary habits. Measurements of body mass index (BMI), waist/hip ratio (WHR), blood pressure, functional capacity, total cholesterol, triglyceride, and lipoprotein subfractions were taken before and after the program. Changes in 10-year risk estimate for coronary heart disease and stroke were calculated using Framingham risk equations. SETTING: Three urban general practices patients: 31 healthy, sedentary 50- to 65-year-old participants recruited following contact by their general practitioner. MAIN RESULTS: The mean time spent walking by the intervention group was 27.72 (+/-9.79) min/day: their adherence to the protocol was 90.3%. Significant decreases in systolic and diastolic blood pressure, reduction in stroke risk, and increased functional capacity were found within the walking group between baseline and 12-week measurements. No changes were found in these parameters within the control group. Significant reductions in 10-year risk of CHD were observed in both groups. No significant changes were found in lipid levels or anthropometric measurements in either group. CONCLUSIONS: The study provides evidence for the benefit to fitness and cardiovascular risk of the "30-min brisk walking, 5 days a week" message to people aged 50-65 years who participated in an unsupervised home-based walking program. Further study to overcome the problem of poor recruitment and determine the minimum effective dose of exercise to improve cardiovascular risk prediction scores is required.

Aged↗
PubMed1997

Randomized placebo-controlled trial of brisk walking in the prevention of postmenopausal osteoporosis.

OBJECTIVE: to evaluate the effects of brisk walking on bone mineral density in women who had suffered an upper limb fracture. DESIGN: randomized placebo-controlled trial. Assessments of bone mineral density were made before and at 1 and 2 years after intervention. Standardized and validated measures of physical capacity, self-rated health status and falls were used. SETTING: district general hospital outpatient department. SUBJECTS: 165 women drawn from local accident and emergency departments with a history of fracture of an upper limb in the previous 2 years. Women were randomly allocated to intervention (self-paced brisk walking) or placebo (upper limb exercises) groups. INTERVENTION: both groups were seen at 3-monthly intervals to assess progress, measure physical capacity and maintain enthusiasm. The brisk-walking group were instructed to progressively increase the amount and speed of walking in a manner that suited them. The upper limb exercise placebo group were asked to carry out a series of exercises designed to improve flexibility and fine hand movements, appropriate for a past history of upper limb fracture. RESULTS: drop-outs from both intervention and placebo groups were substantial (41%), although there were no significant differences in bone mineral density, physical capacity or health status between drop-outs and participants. At 2 years, among those completing the trial, bone mineral density at the femoral neck had fallen in the placebo group to a greater extent than in the brisk-walking group [mean net difference between intervention and placebo groups 0.019 g/cm2, 95% confidence interval (CI) -0.0026 to +0.041 g/cm2, P = 0.056]. Lumbar spine bone mineral density had increased to a similar extent (+0.017 g/cm2) in both groups. The cumulative risk of falls was higher in the brisk-walking group (excess risk of 15 per 100 person-years, 95% CI 1.4-29 per 100 person-years, P < 0.05). There were no significant differences in clinical or spinal x-ray fracture risk or self-rated health status between intervention and placebo groups. CONCLUSION: the promotion of exercise through brisk-walking advice given by nursing staff may have a small, but clinically important, impact on bone mineral density but is associated with an increased risk of falls. Self-paced brisk walking is difficult to evaluate in randomized controlled trials because of drop-outs, placebo group exercise, limited compliance and lack of standardization of the duration and intensity of walking. Further work is needed to evaluate the best means of safely achieving increased activity levels in different groups, such as older women and those at high risk of fractures.

Accidental Falls↗
PubMedDate not supplied

A randomized control trial of new tailored walking campaigns in an employee sample.

Public health groups use mass media communications to address the problem of sedentary behaviour. However, these campaigns are poorly evaluated and lack tailoring. Campaigns and questionnaires were developed based on existing theoretical, cross-sectional, and qualitative data regarding how to promote walking with people who are not regularly active. Subjects were volunteer white-collar employees (n = 181) randomly allocated by quota to the campaigns, or control, for one week. One-hundred-thirty-eight subjects (76.2%) completed pre- and postcampaign questionnaires. This study successfully (1) developed four new tailored campaigns to promote walking according to a formalized process that health promoters can adapt and refine, (2) developed a complimentary measure of outcomes, and (3) compared the new campaigns with the English Health Education Authority (HEA) "Active for Life" campaign (control).

Adult↗
PubMed2001

Bone mineral density during reduction, maintenance and regain of body weight in premenopausal, obese women.

Weight loss may lead to bone loss but little is known about changes in bone mass during regain of reduced weight. We studied changes in bone mineral density (BMD) and bone mineral content (BMC) during voluntary weight reduction and partial regain. The study consisted of three phases: a 3 month weight reduction with very-low-energy diet (VLED), a 9 month randomized, controlled walking intervention period with two training groups (target energy expenditure 4.2 or 8.4 MJ/week) and a 24-month follow-up. The participants were premenopausal women with a mean body mass index of 34.0 (SD 3.6) kg/m2. Seventy-four of 85 subjects completed the whole study. Total body, lumbar spine, proximal femur and dominant radius BMD and BMC were measured with dual-energy X-ray absorptiometry (DXA). The mean weight loss during VLED was 13.2 (3.4) kg, accompanied by unchanged total body BMC and decreased lumbar, trochanteric and radial BMD (p < 0.05). During months 3-36, an average of 62% of the weight loss was regained, total body BMC decreased and trochanteric BMD increased (p < 0.05). At the end of the study, total body BMC and lumbar and femoral neck BMD were lower than initially (p < 0.05). Weight change throughout the study correlated significantly with the change in radial (r = 0.54), total body (r = 0.39) and trochanteric (r = 0.37) BMD. Exercise-group assignment had no effect on BMD at weight-bearing sites. In conclusion, the observed changes in BMD and BMC during weight reduction and its partial regain were clinically small and partly reversible. More studies are needed to clarify whether the observed weight changes in BMD and BMC are real or are artifacts arising from assumptions, inaccuracies and technical limitations of DXA.

Absorptiometry, Photon↗
PubMed2003

Structural analysis of the ErbB-2 receptor using monoclonal antibodies: Implications for receptor signalling.

The extracellular part of ErbB-2 is formed by 4 domains, specifically, L1, L2 that adopt a beta-helical structure and S1, S2 that consist of several cysteine-rich, EGF-fold modules. These ectodomains mediate ErbB-2 dimerisation with itself or with other members of the epidermal growth factor receptor (EGFR) family, events essential to both ErbB-2 signaling and the development of certain malignancies. The anti-ErbB-2 monoclonal antibodies N12, N28 and L87 bind to the polypeptides C531-A586, T216-C235 and C220-C235 respectively. In this study, glycine walking and random mutagenesis were used to further delineate the critical residues involved in antibody binding. A molecular model of ErbB-2 ectodomains was then constructed based on the recently published coordinates of the EGFR (EGFR) model. This model rationalized successfully many features of our epitope mapping, including their location in modules within the S1 and S2 domains and the importance of Arg545, Gln548 and Leu561 for N12 binding. Further investigation of the functional effects of the anti-ErbB-2 monoclonal antibodies demonstrated that N28 strongly stimulated ErbB-2 phosphorylation and MAPK activation whereas N12 had no effect. As bivalency is required for the action of these antibodies we propose that at least 2 different kinds of ErbB-2 homodimers can be formed as relative rotational isomers and that the S1 and S2 domains are instrumental in determining the relative orientations of the ErbB-2 homodimers, such that different signaling effects are induced.

Antibodies, Monoclonal↗
PubMed1988

Structural analysis of polymers of sickle cell hemoglobin. I. Sickle hemoglobin fibers.

The structure of fibers of deoxyhemoglobin S has been under investigation for several years and a number of different models have been proposed for the arrangement of molecules within the particles. We have used reconstruction and modeling techniques in our analysis of these structures. Several new approaches have been employed in this analysis in order to provide improved estimates of the co-ordinates, pairing, and polarity of the hemoglobin S molecules. Fibers have a variable pitch and, in order to minimize distortions in the reconstructed density maps associated with these variations in pitch, we have developed an iterative procedure to measure the instantaneous pitch and have modified the reconstruction algorithm to incorporate the measured values. This procedure improves the accuracy with which the hemoglobin S molecules can be located in the density maps. Furthermore, the determination of the instantaneous pitch allows us to measure directly the rotation of the individual hemoglobin molecules. These measurements are in excellent agreement with the values predicted using a random angular walk model (as originally proposed for F-actin) to describe the variable pitch. The reconstructions confirm that the fiber consists of 14 strands of hemoglobin S arranged in a hexagonally shaped cross-section. We have determined the pairing of the molecules to form double strands directly from the density maps by identifying the molecules that have intermolecular distances that conform to those of double strands in the Wishner-Love crystal. The seven double strands identified in this manner are consistent with the strand pairings proposed by Dykes et al. (1979) rather than the alternate pairings proposed by Rosen & Magdoff-Fairchild (1985). In addition, we have for the first time determined the polarity of the double strands directly from the reconstruction data. This was achieved using a procedure that amounts to essentially "dissecting" individual double strands from the reconstructed density maps so that their density distribution could be examined independently of the neighboring double strands. Knowledge of the relative polarities of the double strands is essential for determining the intermolecular interactions that stabilize the fiber.

Crystallography↗
PubMed2006

Biperiden-induced delirium model in rats: a behavioral and electroencephalographic study.

AIMS AND METHODS: In order to elucidate the neural mechanisms of delirium, we administered the anticholinergic drug, biperiden (40 mg/kg i.p.), to 10 adult male Wistar rats and examined the resulting polygraphic recordings, including electroencephalography (EEG), electrooculography (EOG), and electromyography (EMG), for 60 min following injection. EEG data were investigated quantitatively by power spectrum analyses using fast Fourier transformation. Ten male Wistar rats receiving saline (i.p.) were used as the control group. RESULTS: Treated rats demonstrated two types of alternating behavioral change: a hyperactive and hypoactive state. In the hyperactive state, rapid walking, excessive random sniffing, and retropulsion were observed, with EEG desynchronization (significantly increased alpha1 (8.0-10.0 Hz), alpha2 (10.0-13.0 Hz), and beta (13.0-30.0 Hz) power values), as well as EEG slowing (significantly increased delta (0.5-4.0 Hz) and theta1 (4.0-6.0 Hz) power values): significantly marked rapid eye movement, and increased EMG activity. In the hypoactive state, motor arrest and drowsiness were observed, with prominent EEG slowing (significantly increased delta and theta1 power values): significantly decreased rapid eye movement and moderately decreased EMG activity. On the other hand, the control group did not show any behavioral or polygraphic changes. CONCLUSIONS: The behavioral and polygraphic changes induced by biperiden administration in rats are similar to those of delirium in humans. Therefore, it is proposed that biperiden-treated rats are a good delirium model and the anticholinergic mechanism is one of the potent factors in the development of delirium in humans.

Acetylcholine↗
PubMed2005

Quantitating intracellular transport of polyplexes by spatio-temporal image correlation spectroscopy.

Quantitatively understanding how nonviral gene delivery vectors (polyplexes) are transported inside cells is essential before they can be optimized for gene therapy and medical applications. In this study, we used spatio-temporal image correlation spectroscopy (ICS) to follow polymer-nucleic acid particles (polyplexes) of various sizes and analyze their diffusive-like and flow behaviors intracellularly to elucidate the mechanisms responsible for their transport. ICS is a quantitative imaging technique that allows the assessment of particle motion in complex systems, although it has not been widely used to date. We find that the internalized polyplexes are able to use microtubule motors for intracellular trafficking and exhibit different transport behaviors for short (<10 s) versus long (approximately 60 s) correlation times. This motion can be explained by a memory effect of the microtubule motors. These results reveal that, although microtubule motor biases may be present for short periods of time, resulting in a net directional velocity, the overall long-term motion of the polyplexes is best described as a random walk-like process. These studies suggest that spatio-temporal ICS is a powerful technique for assessing the nature of intracellular motion and provides a quantitative tool to compare the transport of different objects within a living cell.

Biological Transport↗
PubMed2004

Loss of caveolin-1 polarity impedes endothelial cell polarization and directional movement.

The ability of a cell to move requires the asymmetrical organization of cellular activities. To investigate polarized cellular activity in moving endothelial cells, human endothelial cells were incubated in a Dunn chamber to allow migration toward vascular endothelial growth factor. Immunofluorescent staining with a specific antibody against caveolin-1 revealed that caveolin-1 was concentrated at the rear of moving cells. Similarly, monolayer scraping to induce random cell walk resulted in relocation of caveolin-1 to the cell rear. These results suggest that posterior polarization of caveolin-1 is a common feature both for chemotaxis and chemokinesis. Dual immunofluorescent labeling showed that, during cell spreading, caveolin-1 was compacted in the cell center and excluded from nascent focal contacts along the circular lamellipodium, as revealed by integrin beta1 and FAK staining. When cells were migrating, integrin beta1 and FAK appeared at polarized lamellipodia, whereas caveolin-1 was found at the posterior of moving cells. Notably, wherever caveolin-1 was polarized, there was a conspicuous absence of lamellipod protrusion. Transmission electron microscopy showed that caveolae, similar to their marker caveolin-1, were located at the cell center during cell spreading or at the cell rear during cell migration. In contrast to its unphosphorylated form, tyrosine-phosphorylated caveolin-1, upon fibronectin stimulation, was associated with the focal complex molecule phosphopaxillin along the lamellipodia of moving cells. Thus, unphosphorylated and phosphorylated caveolin-1 were located at opposite poles during cell migration. Importantly, loss of caveolin-1 polarity by targeted down-regulation of the protein prevented cell polarization and directional movement. Our present results suggest a potential role of caveolin polarity in lamellipod extension and cell migration.

Caveolae↗
PubMed2006

The use of rhythmic auditory cues to influence gait in patients with Parkinson's disease, the differential effect for freezers and non-freezers, an explorative study.

PURPOSE: To study the effect of rhythmic auditory cues on gait in Parkinson's disease subjects with and without freezing and in controls. METHOD: A volunteer sample of 20 patients (10 freezers, 10 non-freezers) and 10 age-matched controls performed five randomized cued walking conditions in a gait-laboratory. Auditory cues were administered at baseline frequency, at an increased step frequency of 10 and 20% above baseline and at a decreased step frequency of 10 and 20% below baseline. Mean step frequency, walking speed, stride length and double support duration were collected. RESULTS: Rhythmical auditory cueing induced speed changes in all subjects. Stride length was not influenced by rhythmical auditory cues in controls, whereas patients showed a larger stride length in the -10% condition (p < 0.01). Freezers and non-freezers showed the same response to rhythmical auditory cues. Within group analysis for stride length showed different cueing effects. Stride length decreased at the +10% condition for freezers (p < 0.05), whereas it increased for non-freezers. CONCLUSIONS: This study points to fact that physiotherapists might need to carefully adjust the cueing frequency to the needs of patients with and without freezing. On the basis of the present results we recommend to lower the frequency setting for freezers, whereas for non-freezers an increase of up to +10% may have potential therapeutic use.

Acoustic Stimulation↗
PubMed2006

Enhancement of U4/U6 small nuclear ribonucleoprotein particle association in Cajal bodies predicted by mathematical modeling.

Spliceosomal small nuclear ribonucleoprotein particles (snRNPs) undergo specific assembly steps in Cajal bodies (CBs), nonmembrane-bound compartments within cell nuclei. An example is the U4/U6 di-snRNP, assembled from U4 and U6 monomers. These snRNPs can also assemble in the nucleoplasm when cells lack CBs. Here, we address the hypothesis that snRNP concentration in CBs facilitates assembly, by comparing the predicted rates of U4 and U6 snRNP association in nuclei with and without CBs. This was accomplished by a random walk-and-capture simulation applied to a three-dimensional model of the HeLa cell nucleus, derived from measurements of living cells. Results of the simulations indicated that snRNP capture is optimal when nuclei contain three to four CBs. Interestingly, this is the observed number of CBs in most cells. Microinjection experiments showed that U4 snRNA targeting to CBs was U6 snRNP independent and that snRNA concentration in CBs is approximately 20-fold higher than in nucleoplasm. Finally, combination of the simulation with calculated association rates predicted that the presence of CBs enhances U4 and U6 snRNP association by up to 11-fold, largely owing to this concentration difference. This provides a chemical foundation for the proposal that these and other cellular compartments promote molecular interactions, by increasing the local concentration of individual components.

Base Sequence↗
PubMed1998

Genome properties of beet virus Q, a new furo-like virus from sugarbeet, determined from unpurified virus.

Based solely on the information that beet virus Q (BVQ) contains tubular particles, the entire nucleotide sequence of its tripartite genome was determined from unpurified virus in ca. 40 ml crude sap from locally infected Chenopodium quinoa. A starting sequence for RNA 1 was generated using primers corresponding to highly conserved helicase domains in the respective RNAs of furo-, pomo-, peclu-, hordei- and tobraviruses, and was extended by a walking random-primed cDNA approach. The similarity of the 3' ends of furoviral RNAs allowed starting sequences for BVQ RNAs 2 and 3 to be obtained once the 3' end of RNA 1 was known. BVQ RNA 1 encodes a protein with a methyltransferase-like, a variable and a helicase-like region, and for a readthrough protein which, in addition, contains an RNA-dependent RNA polymerase region. RNA 2 carries the coat protein gene, a coat protein read-through protein gene and two additional ORFs which may have arisen by deletions from an originally larger readthrough domain. RNA 3 carries a triple gene block resembling that of several other rod-shaped viruses. The 5' UTRs of the three RNAs have the potential to form a series of hairpins with C-A and C-C mismatches resembling those found in tymoviral RNAs. The 3' ends can be folded into tRNA-like structures which are preceded by a long hairpin-like structure and an upstream pseudoknot domain. BVQ belongs to the recently proposed genus Pomovirus; it shows evolutionary relationships to furoviruses in sensu stricto, peclu-, hordei-, tobra-, tymo-, tobamo-, carla- and potexviruses.

Amino Acid Sequence↗
PubMed1971

The history and stability of atmospheric oxygen.

There are three processes weakly concentration-dependent that keep changes in concentration of atmospheric pressure from being a random walk-inhibition of net photosynthesis by oxygen, the passage of hydrogen through the oxidizing part of the atmosphere before it escapes from the earth, and burial of reduced carbon in anaerobic water. A stronger regulator seems desirable but remains to be found. The cause of the initial rise in oxygen concentration presents a serious and unresolved quantitative problem.

Air↗