Showing papers by "La Trobe University published in 2005"

Inference by eye: confidence intervals and how to read pictures of data.

Abstract: Wider use in psychology of confidence intervals (CIs), especially as error bars in figures, is a desirable development. However, psychologists seldom use CIs and may not understand them well. The authors discuss the interpretation of figures with error bars and analyze the relationship between CIs and statistical significance testing. They propose 7 rules of eye to guide the inferential use of figures with error bars. These include general principles: Seek bars that relate directly to effects of interest, be sensitive to experimental design, and interpret the intervals. They also include guidelines for inferential interpretation of the overlap of CIs on independent group means. Wider use of interval estimation in psychology has the potential to improve research communication substantially.

A reassessment of genetic limits to evolutionary change

Abstract: An absence of genetic variance in traits under selection is perhaps the oldest explanation for a limit to evolutionary change, but has also been the most easily dismissed. We review a range of theoretical and empirical results covering single traits to more complex multivariate systems, and show that an absence of genetic variance may be more common than is currently appreciated. From a single-trait perspective, we highlight that it is becoming clear that some trait types do not display significant levels of genetic variation, and we raise the possibility that species with restricted ranges may differ qualitatively from more widespread species in levels of genetic variance in ecologically important traits. A common misconception in many life-history studies is that a lack of genetic variance in single traits, and genetic constraints as a consequence of bivariate genetic correlations, are different causes of selection limits. We detail how interpretations of bivariate patterns are unlikely to demonstrate genetic limits to selection in many cases. We advocate a multivariate definition of genetic constraints that emphasizes the presence (or otherwise) of genetic variance in the multivariate direction of selection. For multitrait systems, recent results using longer term studies of organisms, in which more is understood concerning what traits may be under selection, have indicated that selection may exhaust genetic variance, resulting in a limit to the selection response.

Defensins--components of the innate immune system in plants.

Abstract: Plant defensins are small (c.a. 5 kDa), basic, cysteine-rich proteins with antimicrobial activities. They are ubiquitous in plants and form part of the innate immunity arsenal. Plant defensins are encoded by small multigene families and are expressed in various plant tissues, but are best characterized in seeds. They are typically produced as preproteins, however, a small subset are produced as larger precursors with C-terminal prodomains. To date, the three-dimensional solution structures of seven seed- and two floral-derived defensins have been elucidated by (1)H-NMR spectroscopy. Despite limited amino acid sequence identities, these defensins have comparable global folds with features that are characteristic of the cysteine-stabilized alphabeta (CSalphabeta) motif. Interestingly, their structures are remarkably similar to those of insect defensins and scorpion toxins. Functionally, these proteins exhibit a diverse array of biological activities, although they all serve a common function as defenders of their hosts. This review describes the distribution, biosynthesis, structure, function and mode of action of plant defensins and reflects on their potential in agribiotechnological applications.

Foot and Ankle Characteristics Associated With Impaired Balance and Functional Ability in Older People

Abstract: Background. Ageing is associated with changes to the structure and function of the foot and ankle, and there is preliminary evidence that foot problems impair balance and increase the risk of falls. To explore this in more detail, we conducted a study to determine the relative contribution of several foot and ankle characteristics to performance on a range of balance and functional tests. Methods. One hundred seventy-six people (56 men and 120 women, mean age 80.1 years, standard deviation 6.4 years) residing in a retirement village underwent tests of foot and ankle characteristics (including foot posture, range of motion, strength, and deformity), sensorimotor function (including vision, sensation, strength, and reaction time), and balance and functional ability (including tests of standing balance, leaning balance, stepping, sit-to-stand, and walking speed). Results. Many foot and ankle characteristics and sensorimotor measures were associated with performance on the balance and functional tests in univariate analyses. Multiple regression analysis consistently revealed that ankle flexibility, plantar tactile sensitivity, and toe plantarflexor strength were significant and independent predictors of balance and functional test performance, explaining up to 59% of the variance in these test scores. Conclusions. Foot and ankle characteristics, particularly ankle flexibility, plantar tactile sensation, and strength of toe plantarflexor muscles, are significant independent predictors of balance and functional ability in older people. Programs to improve the strength and flexibility of the foot and interventions to augment plantar sensation may be beneficial in improving mobility and reducing the risk of falls.

Curdlan and other bacterial (1→3)-β-d-glucans

Abstract: Three structural classes of (1-->3)-beta-D-glucans are encountered in some important soil-dwelling, plant-associated or human pathogenic bacteria. Linear (1-->3)-beta-glucans and side-chain-branched (1-->3,1-->2)-beta-glucans are major constituents of capsular materials, with roles in bacterial aggregation, virulence and carbohydrate storage. Cyclic (1-->3,1-->6)-beta-glucans are predominantly periplasmic, serving in osmotic adaptation. Curdlan, the linear (1-->3)-beta-glucan from Agrobacterium, has unique rheological and thermal gelling properties, with applications in the food industry and other sectors. This review includes information on the structure, properties and molecular genetics of the bacterial (1-->3)-beta-glucans, together with an overview of the physiology and biotechnology of curdlan production and applications of this biopolymer and its derivatives.

A Rapid Shift in a Classic Clinal Pattern in Drosophila Reflecting Climate Change

Abstract: Geographical clines in genetic polymorphisms are widely used as evidence of climatic selection and are expected to shift with climate change. We show that the classic latitudinal cline in the alcohol dehydrogenase polymorphism of Drosophila melanogaster has shifted over 20 years in eastern coastal Australia. Southern high-latitude populations now have the genetic constitution of more northerly populations, equivalent to a shift of 4° in latitude. A similar shift was detected for a genetically independent inversion polymorphism, whereas two other linked polymorphisms exhibiting weaker clinal patterns have remained relatively stable. These genetic changes are likely to reflect increasingly warmer and drier conditions and may serve as sensitive biomarkers for climate change.

Particle bombardment and the genetic enhancement of crops: Myths and realities

Abstract: DNA transfer by particle bombardment makes use of physical processes to achieve the transformation of crop plants. There is no dependence on bacteria, so the limitations inherent in organisms such as Agrobacterium tumefaciens do not apply. The absence of biological constraints, at least until DNA has entered the plant cell, means that particle bombardment is a versatile and effective transformation method, not limited by cell type, species or genotype. There are no intrinsic vector requirements so transgenes of any size and arrangement can be introduced, and multiple gene cotransformation is straightforward. The perceived disadvantages of particle bombardment compared to Agrobacterium-mediated transformation, i.e. the tendency to generate large transgene arrays containing rearranged and broken transgene copies, are not borne out by the recent detailed structural analysis of transgene loci produced by each of the methods. There is also little evidence for major differences in the levels of transgene instability and silencing when these transformation methods are compared in agriculturally important cereals and legumes, and other non-model systems. Indeed, a major advantage of particle bombardment is that the delivered DNA can be manipulated to influence the quality and structure of the resultant transgene loci. This has been demonstrated in recently reported strategies that favor the recovery of transgenic plants containing intact, single-copy integration events, and demonstrating high-level transgene expression. At the current time, particle bombardment is the most efficient way to achieve plastid transformation in plants and is the only method so far used to achieve mitochondrial transformation. In this review, we discuss recent data highlighting the positive impact of particle bombardment on the genetic transformation of plants, focusing on the fate of exogenous DNA, its organization and its expression in the plant cell. We also discuss some of the most important applications of this technology including the deployment of transgenic plants under field conditions.

Researchers misunderstand confidence intervals and standard error bars.

Abstract: Little is known about researchers' understanding of confidence intervals (CIs) and standard error (SE) bars. Authors of journal articles in psychology, behavioral neuroscience, and medicine were invited to visit a Web site where they adjusted a figure until they judged 2 means, with error bars, to be just statistically significantly different (p < .05). Results from 473 respondents suggest that many leading researchers have severe misconceptions about how error bars relate to statistical significance, do not adequately distinguish CIs and SE bars, and do not appreciate the importance of whether the 2 means are independent or come from a repeated measures design. Better guidelines for researchers and less ambiguous graphical conventions are needed before the advantages of CIs for research communication can be realized.

Eccentric decline squat protocol offers superior results at 12 months compared with traditional eccentric protocol for patellar tendinopathy in volleyball players

Abstract: Background: Conservative treatment of patellar tendinopathy has been minimally investigated. Effective validated treatment protocols are required. Objectives: To investigate the immediate (12 weeks) and long term (12 months) efficacy of two eccentric exercise programmes for the treatment of patellar tendinopathy. Methods: This was a prospective randomised controlled trial of 17 elite volleyball players with clinically diagnosed and imaging confirmed patellar tendinopathy. Participants were randomly assigned to one of two treatment groups: a decline group and a step group. The decline group were required to perform single leg squats on a 25° decline board, exercising into tendon pain and progressing their exercises with load. The step group performed single leg squats on a 10 cm step, exercising without tendon pain and progressing their exercises with speed then load. All participants completed a 12 week intervention programme during their preseason. Outcome measures used were the Victorian Institute of Sport Assessment (VISA) score for knee function and 100 mm visual analogue scale (VAS) for tendon pain with activity. Measures were taken throughout the intervention period and at 12 months. Results: Both groups had improved significantly from baseline at 12 weeks and 12 months. Analysis of the likelihood of a 20 point improvement in VISA score at 12 months revealed a greater likelihood of clinical improvements in the decline group than the step group. VAS scores at 12 months did not differ between the groups. Conclusions: Both exercise protocols improved pain and sporting function in volleyball players over 12 months. This study indicates that the decline squat protocol offers greater clinical gains during a rehabilitation programme for patellar tendinopathy in athletes who continue to train and play with pain.

Footwear characteristics and foot problems in older people.

Abstract: Background: Foot problems are common in older people, however the contribution of incorrectly fitting footwear and heel elevation to the development of foot pain and deformity has no

The epidemiology of low back pain in primary care

Abstract: This descriptive review provides a summary of the prevalence, activity limitation (disability), care-seeking, natural history and clinical course, treatment outcome, and costs of low back pain (LBP) in primary care. LBP is a common problem affecting both genders and most ages, for which about one in four adults seeks care in a six-month period. It results in considerable direct and indirect costs, and these costs are financial, workforce and social. Care-seeking behaviour varies depending on cultural factors, the intensity of the pain, the extent of activity limitation and the presence of co-morbidity. Care-seeking for LBP is a significant proportion of caseload for some primary-contact disciplines. Most recent-onset LBP episodes settle but only about one in three resolves completely over a 12-month period. About three in five will recur in an on-going relapsing pattern and about one in 10 do not resolve at all. The cases that do not resolve at all form a persistent LBP group that consume the bulk of LBP compensable care resources and for whom positive outcomes are possible but not frequent or substantial.

Three‐dimensional gait biomechanics in Parkinson's disease: Evidence for a centrally mediated amplitude regulation disorder

Abstract: We examined whether people with Parkinson's disease (PD) have a central amplitude regulation disorder using three-dimensional (3-D) gait analyses to compare the effects of medication and attentional strategies on gait in 12 PD subjects and 12 matched comparison subjects. Subjects with PD first performed several 10-m gait trials at preferred speed while off levodopa. They then walked at preferred speed on levodopa; off levodopa with cues; and on levodopa with cues. Control subjects walked at preferred speed and then with visual cues to match their stride length to PD values. As well as spatiotemporal footstep data, pelvic and lower limb kinematic profiles and angle-angle diagrams were produced for sagittal, coronal, and transverse plane movements using a 3-D motion analysis system. In people with PD, decreased step length was accompanied by reduced movement amplitude across all lower limb joints, in all movement planes. When control subjects were required to walk with short steps matched to the size of PD comparisons, they displayed a similar multijoint reduction in amplitude. For PD subjects, both levodopa and visual cues increased movement amplitude across all lower limb joints. Amplitude increased further when levodopa and visual cues were combined, resulting in normalization of step length. This finding suggested that reduced step length is due to a mismatch between cortically selected movement amplitude and basal ganglia maintenance mechanisms. Levodopa and cues normalized amplitude across all joints by altering motor set and bypassing defective basal ganglia mechanisms.

Abnormal elevation of FMR1 mRNA is associated with psychological symptoms in individuals with the fragile X premutation

Abstract: Until recently, individuals with premutation alleles (55-200 CGG repeats) of the fragile X mental retardation 1 (FMR1) gene were believed to be psychologically unaffected. However, the recent documentation of abnormal elevation of FMR1 mRNA, discovery of fragile X-associated tremor/ataxia syndrome (FXTAS), and reports of psychiatric disorders in children and adults with the premutation have suggested a pathogenic gene-brain-behavior mechanism. In a large collaborative study, 68 men and 144 women with the FMR1 premutation completed a psychological symptoms checklist and FMR1 genetic testing, including determination of CGG repeat size, percentage of FMR1 protein (FMRP)-positive lymphocytes, and FMR1 mRNA levels. Relative to published norms, men and women with FXTAS symptoms reported higher levels of several types of psychological symptoms. In addition, men and women with the premutation and no overt evidence of FXTAS reported higher levels of obsessive-compulsive symptoms. Elevated FMR1 mRNA, but not CGG repeat size or reduced FMRP (as measured by immunocytochemistry), was significantly associated with increased psychological symptoms, predominantly obsessive-compulsive symptoms and psychoticism, in premutation men with and without FXTAS symptoms. There was no relationship between CGG repeat size, FMR1 mRNA or FMRP and psychological symptoms in premutation women unless the sample was restricted to those with skewed X-activation ratio toward >50% active premutation alleles. The results of this study support the hypothesis that FMR1 function is associated with psychological difficulties in individuals with the premutation, and provide evidence concordant with an RNA toxic gain-of-function model in a neuropsychiatric phenotype.

Relative importance of plastic vs genetic factors in adaptive differentiation: geographical variation for stress resistance in Drosophila melanogaster from eastern Australia

Abstract: Summary 1 Heritable clinal patterns for stress resistance traits have been described in a number of invertebrate species but patterns are usually characterized on populations reared under constant conditions. Here we examined the impact of simulated seasonal variation in temperature/photoperiod as well as constant conditions on stress resistance in eight Drosophila melanogaster populations from eastern Australia across a latitude range of 27 degrees. 2 Desiccation resistance was relatively higher under summer compared with winter/constant conditions, but this trait and starvation resistance did not exhibit clinal variation. Winter conditions increased cold resistance as measured by chill coma recovery time, and decreased heat resistance as measured by time to knock down in a vial. 3 Clinal patterns were evident for the thermal resistance traits regardless of conditions, and involved increased heat resistance and decreased cold resistance in tropical populations. Latitudinal patterns were steeper for cold resistance than for heat resistance. 4 To compare the relative impact of plastic vs genetic changes along the cline, differences in trait means were expressed relative to differences between populations from cline ends. For cold and heat resistance, differences between environmental conditions were approximately 1·5× greater than the heritable differences.

Isolation, solution structure, and insecticidal activity of kalata B2, a circular protein with a twist: do Möbius strips exist in nature?

Abstract: A large number of macrocyclic miniproteins with diverse biological activities have been isolated from the Rubiaceae, Violaceae, and Cucurbitaceae plant families in recent years. Here we report the three-dimensional structure determined using H-1 NMR spectroscopy and demonstrate potent insecticidal activity for one of these peptides, kalata B2. This peptide is one of the major components of an extract from the leaves of the plant Oldenlandia affinis. The structure consists of a distorted triple-stranded beta-sheet and a cystine knot arrangement of the disulfide bonds and is similar to those described for other members of the cyclotide family. The unique cyclic and knotted nature of these molecules makes them a fascinating example of topologically complex proteins. Examination of the sequences reveals that they can be separated into two subfamilies, one of which contains a larger number of positively charged residues and has a bracelet-like circularization of the backbone. The second subfamily contains a backbone twist due to a cis-peptidyl-proline bond and may conceptually be regarded as a molecular Mobius strip. Kalata B2 is the second putative member of the Mobius cyclotide family to be structurally characterized and has a cis-peptidyl-proline bond, thus validating the suggested name for this subfamily of cyclotides. The observation that kalata B2 inhibits the growth and development of Helicoverpa armigera larvae suggests a role for the cyclotides in plant defense. A comparison of the sequences and structures of kalata B1 and B2 provides insight into the biological activity of these peptides.

Taz1, an Outer Mitochondrial Membrane Protein, Affects Stability and Assembly of Inner Membrane Protein Complexes: Implications for Barth Syndrome

Abstract: The Saccharomyces cerevisiae Taz1 protein is the orthologue of human Tafazzin, a protein that when inactive causes Barth Syndrome (BTHS), a severe inherited X-linked disease. Taz1 is a mitochondrial acyltransferase involved in the remodeling of cardiolipin. We show that Taz1 is an outer mitochondrial membrane protein exposed to the intermembrane space (IMS). Transport of Taz1 into mitochondria depends on the receptor Tom5 of the translocase of the outer membrane (TOM complex) and the small Tim proteins of the IMS, but is independent of the sorting and assembly complex (SAM). TAZ1 deletion in yeast leads to growth defects on nonfermentable carbon sources, indicative of a defect in respiration. Because cardiolipin has been proposed to stabilize supercomplexes of the respiratory chain complexes III and IV, we assess supercomplexes in taz1Δ mitochondria and show that these are destabilized in taz1Δ mitochondria. This leads to a selective release of a complex IV monomer from the III2IV2 supercomplex. In addition, assembly analyses of newly imported subunits into complex IV show that incorporation of the complex IV monomer into supercomplexes is affected in taz1Δ mitochondria. We conclude that inactivation of Taz1 affects both assembly and stability of respiratory chain complexes in the inner membrane of mitochondria.

A randomized controlled trial of psychological interventions for postnatal depression

Abstract: OBJECTIVES: First, to establish the efficacy of psychological interventions versus routine primary care for the management of postnatal depression (PND). Secondly, to provide a direct comparison of cognitive-behavioural therapy (CBT) versus counselling and, finally, to compare the relative value of group and individual delivery formats. DESIGN: The study involved 192 depressed women drawn from a large community screening programme in Melbourne, Australia and allocated to cognitive behaviour therapy, counselling, or routine primary care. Baseline and post-intervention measures of depression and anxiety were collected in the form of validated self-report inventories. METHOD: Women were screened in the community and diagnosis of depression confirmed with a standardized psychiatric interview. Interventions were of 12 weeks duration, including three partner sessions, and adhered to a structured manual. RESULTS: Psychological intervention per se was superior to routine care in terms of reductions in both depression and anxiety following intervention. CONCLUSIONS: For those women with PND, psychological intervention is a better option than routine care, leading to clinically significant reduction of symptoms. Counselling may be as effective as group cognitive behaviour therapy. The benefits of psychological intervention may be maximized by being delivered on a one-to-one basis.

Validity of 3 Clinical Techniques for the Measurement of Static Foot Posture in Older People

Abstract: Study Design Concurrent validity study. Objectives To determine the validity of 3 clinical methods for assessing static foot posture in older people. Background Variations in the structure of the medial longitudinal arch are thought to influence lower extremity function; however, the validity of clinical measurements has not been fully established. Methods and Measures Clinical measurements of arch index (AI), navicular height (NH), and Foot Posture Index (FPI) were performed on 95 subjects (31 men and 64 women), aged 62 to 94 years (mean ± SD, 78.6 ± 6.5 years). These clinical measurements were then correlated with 3 arch-related measurements from radiographs: navicular height (NHr), calcaneal inclination angle (CIA), and calcaneal first metatarsal angle (C1MA). Results All 3 clinical measures demonstrated significant associations with each of the radiographic parameters (P<.01). NH was highly correlated with NHr (Pearson r = 0.79), followed by C1MA (r = −0.53), and CIA (r = 0.44). The AI was highly corr...

Green advertising effects on attitude and choice of advertising themes

Abstract: The aims of this article is to analyse whether there are differences in green advertisement attitudes between high involved and low involved consumers, to compare high and low involvement consumer’s cognitive responses and affective responses towards advertisements and examine the extent of the importance on certain themes that both high involvement and low involvement consumers consider. Themes such as company image, environmental labels, and product recycling symbols. A random sample of 207 consumers was taken from Victoria (Australia). The study shows that there are differences between the two groups in terms of their attitude towards green advertising with respect to all the dimensions and the low involved customers appear to have a stronger disregard for the green advertising across all the perceptive measures towards green advertising. The findings provide useful insights to practitioners as to the type of themes preferred for green advertising.

Falls and injury prevention should be part of every stroke rehabilitation plan

Abstract: Objective: To evaluate falls incidence, circumstances and consequences in people who return home after stroke rehabilitation, so that appropriate falls and injury prevention strategies can be developed.Design: Prospective cohort study.Setting: Community.Subjects: Fifty-six subjects with stroke who were participating in a rehabilitation programme and returning to live in a community setting completed the study.Main measures: Subjects completed a prospective falls diary for six months after discharge from rehabilitation, and were interviewed after falls. Physical function was measured by the Berg Balance Scale (BBS) and the Functional Independence Measure (FIM).Results: Forty-six per cent of people (26/56) fell, with most falls (63/103 falls) occurring in the two months after discharge from rehabilitation. One subject had 37 similar falls and these falls were excluded from further analysis. Falls occurred more often indoors (50/66), during the day (46/66) and towards the paretic side (25/66). People require...