Making science real:Photo-sharing in biology and chemistry

In this paper, we examine students’ reflections about the value of two photo-sharing activities that were implemented in undergraduate Biology and Chemistry subjects. Both activities aimed, broadly, to provide support for authentic and meaningful learning experiences in undergraduate science. Although the activities were similar – both required students to capture and share images as part of an independent inquiry activity – students in the Biology case study were more positive, overall, than the Chemistry students in their evaluation of the activity. In this paper, we examine the findings from the two case studies in parallel to provide insight into our understanding of meaningful learning in undergraduate science. The results suggest that, for meaningful learning to occur, the learning activity needs to be well aligned with students’ individual learning goals and with the objectives and characteristics of the course. In the two case studies examined in this paper, this alignment was successful for the Biology case study but less successful in the Chemistry case study

Susceptibility of Pseudomonas aeruginosa Biofilm to Alpha-Helical Peptides: D-enantiomer of LL-37

Pseudomonas aeruginosa is a highly versatile opportunistic pathogen and its ability to produce biofilms is a direct impediment to the healing of wounds and recovery from infection. Interest in anti-microbial peptides (AMPs) has grown due to their potential therapeutic applications and their possible use against antibiotic resistant bacteria. LL-37 is the only cathelicidin expressed by humans. In this study, we tested LL-37 and the effect of a protease-resistant LL-37 peptide mimetic, the peptide enantiomer D-LL-37, for anti-microbial and anti-biofilm activity against P. aeruginosa. Both forms of the peptide were equally effective as AMPs with similar killing kinetics. Circular dichroism spectra were obtained to demonstrate the chirality of D- and L-LL-37, and the trypsin resistance of D-LL-37 was confirmed. The helical cathelicidin from the cobra Naja atra (NA-CATH), and synthetic peptide variations (ATRA-1, ATRA-2, NA-CATH:ATRA1-ATRA1) were also tested. Although the cobra cathelicidin and related peptides had strong anti-microbial activity, those tested did not inhibit Pseudomonas biofilm formation, neither did control peptides. Both D- and L-LL-37 inhibited the attachment of Pseudomonas to a 96-well plate and decreased the amount of pre-formed (established) biofilm. D-LL-37 is able to promote Pseudomonas motility and decrease biofilm formation by altering the rate of twitching as well as by downregulating the expression of the biofilm-related genes, rhlA and rhlB, similar to L-LL-37. Both L- and D-LL-37 protected Galleria mellonella in vivo against Pseudomonas infection, while NA-CATH:ATRA1-ATRA1 peptide did not. This study demonstrates the ability and equivalence of D-LL-37 compared to L-LL-37 to promote bacterial twitching motility and inhibit biofilm formation, and protect against in vivo infection, and suggests that this peptide could be a critical advancement in the development of new treatments for P. aeruginosa infection

The potential of virtual laboratories for distance education science teaching: reflections from the development and evaluation of a virtual chemistry laboratory

A virtual chemistry laboratory has been developed at Charles Sturt University, based on an accurate 3D model of the Wagga Wagga undergraduate teaching laboratory. The initial version of the virtual laboratory has been designed to enable distance education chemistry students to become familiar with the laboratory prior to their residential school. It allows for free exploration and for collecting and assembling items of apparatus. It also allows students to read information about the items of apparatus and about laboratory procedures. This paper describes the current features of the virtual laboratory and discusses the pedagogical rationale for its development. Results from questionnaires completed by pilot testers and by the first group of students who used it as part of their laboratory orientation are included. The results of tests comparing the laboratory familiarity of students who used the virtual laboratory with those who viewed equivalent still images are also presented. The paper concludes with a description of features to be added during the next stage of development, which will include the ability for students to undertake virtual experiments while exploring concepts using macroscopic, molecular and symbolic representations

Helical cationic antimicrobial peptide length and its impact on membrane disruption

AbstractCationic antimicrobial peptides (CAMPs) are important elements of innate immunity in higher organisms, representing an ancient defense mechanism against pathogenic bacteria. These peptides exhibit broad-spectrum antimicrobial activities, utilizing mechanisms that involve targeting bacterial membranes. Recently, a 34-residue CAMP (NA-CATH) was identified in cDNA from the venom gland of the Chinese cobra (Naja atra). A semi-conserved 11-residue pattern observed in the NA-CATH sequence provided the basis for generating an 11-residue truncated peptide, ATRA-1A, and its corresponding D-peptide isomer. While the antimicrobial and biophysical properties of the ATRA-1A stereoisomers have been investigated, their modes of action remain unclear. More broadly, mechanistic differences that can arise when investigating minimal antimicrobial units within larger naturally occurring CAMPs have not been rigorously explored. Therefore, the studies reported here are focused on this question and the interactions of full-length NA-CATH and the truncated ATRA-1A isomers with bacterial membranes. The results of these studies indicate that in engineering the ATRA-1A isomers, the associated change in peptide length and charge dramatically impacts not only their antimicrobial effectiveness, but also the mechanism of action they employ relative to that of the full-length parent peptide NA-CATH. These insights are relevant to future efforts to develop shorter versions of larger naturally occurring CAMPs for potential therapeutic applications

What factors contribute to students’ confidence in chemistry laboratory sessions and does preparation in a virtual laboratory help?

Many undergraduate students studying chemistry subjects at Charles Sturt University (CSU) do so by Distance Education (DE). CSU has been offering subjects in chemistry in distance mode for more than 20 years. One of the greatest problems that confronts us, and others (Hollingworth and McLoughlin 2001; Kennepohl and Last 2000) in providing DE subjects is how to adequately address the teaching of a laboratory component. The practical work for CSU DE chemistry subjects is completed at intensive three or four day residential schools. Thus, DE students have only a few days to face the challenges that are spread out over many weeks for on-campus students. Providing a quality laboratory experience for these students within that short period and within the constraints of our resources is the subject of ongoing review at CSU. Problems associated with high stress and information overload for the laboratory component in DE had been noted anecdotally and in the literature (e.g., Loonat 1996). Adequately preparing DE students for residential school is a difficult task. One strategy we have adopted to help prepare DE students has been the provision on CD-ROM of a 3D virtual laboratory, which is an accurate representation of the teaching laboratories. In a paper at last year’s UniServe Symposium (Dalgarno, Bishop and Bedgood 2003), we hypothesised that as a pre-laboratory familiarisation tool, the virtual laboratory would include the following potential benefits: • students would feel more relaxed and comfortable in the laboratory; • less laboratory time would be wasted looking for items of apparatus; • students would be more likely to assemble and use apparatus in the correct way leading to more meaningful experimental results; and • students could devote more of their attention to the chemistry concepts involved in the experiments because they would already be familiar with the procedural aspects of the task (p. 91). This paper presents the results of a qualitative and quantitative study of the laboratory experience of DE students in first year chemistry subjects which provides initial tests of these hypotheses, as well as expanding our understanding of factors involved with the student experience of laboratory

Personal stigma and use of mental health services among people with depression in a general population in Finland

Background - A minority of people suffering from depression seek professional help for themselves. Stigmatizing attitudes are assumed to be one of the major barriers to help seeking but there is only limited evidence of this in large general population data sets. The aim of this study was to analyze the associations between mental health attitude statements and depression and their links to actual use of mental health services among those with depression. Methods - We used a large cross-sectional data set from a Finnish population survey (N = 5160). Attitudes were measured by scales which measured the belief that people with depression are responsible for their illness and their recovery and attitudes towards antidepressants. Desire for social distance was measured by a scale and depression with the Composite International Diagnostic Interview Short Form (CIDI-SF) instrument. Use of mental health services was measured by self-report. Results - On the social discrimination scale, people with depression showed more social tolerance towards people with mental problems. They also carried more positive views about antidepressants. Among those with depression, users of mental health services, as compared to non-users, carried less desire for social distance to people with mental health problems and more positive views about the effects of antidepressants. More severe depression predicted more active use of services. Conclusions - Although stronger discriminative intentions can reduce the use of mental health services, this does not necessarily prevent professional service use if depression is serious and views about antidepressant medication are realistic.peerReviewe