Calcineurin-Aα alpha activation enhances the structure and function of regenerating muscles after myotoxic injury

Calcineurin signaling is essential for successful muscle regeneration. Although calcineurin inhibition compromises muscle repair, it is not known whether calcineurin activation can enhance muscle repair after injury. Tibialis anterior (TA) muscles from adult wild-type (WT) and transgenic mice overexpressing the constitutively active calcineurin-Aα transgene under the control of the mitochondrial creatine kinase promoter (MCK-CnAα*) were injected with the myotoxic snake venom Notexin to destroy all muscle fibers. The TA muscle of the contralateral limb served as the uninjured control. Muscle structure was assessed at 5 and 9 days postinjury, and muscle function was tested in situ at 9 days postinjury. Calcineurin stimulation enhanced muscle regeneration and altered levels of myoregulatory factors (MRFs). Recovery of myofiber size and force-producing capacity was hastened in injured muscles of MCK-CnAα* mice compared with control. Myogenin levels were greater 5 days postinjury and myocyte enhancer factor 2a (MEF2a) expression was greater 9 days postinjury in muscles of MCK-CnAα* mice compared with WT mice. Higher MEF2a expression in regenerating muscles of MCK-CnAα* mice 9 days postinjury may be related to an increase of slow fiber genes. Calcineurin activation in uninjured and injured TA muscles slowed muscle contractile properties, reduced fatigability, and enhanced force recovery after 4 min of intermittent maximal stimulation. Therefore, calcineurin activation can confer structural and functional benefits to regenerating skeletal muscles, which may be mediated in part by differential expression of MRFs.

Phospholipase activity in human mesenteric ischaemia and infarction

Currently, diagnostic tests for mesenteric ischaemia and infarction are inadequate due to poor sensitivity and specificity. In addition, many potential markers appear too late to be clinically useful. At present, definitive diagnosis can only be made at the time of surgery, which is not ideal as surgery is often to be avoided in critically ill and elderly patients. A clinically useful, minimally invasive test is likely to decrease the currently very high mortality rate and allow monitoring of 'at risk' patients during their hospital stay. A two-dimensional electrophoresis based proteomic approach was undertaken to assess plasma protein differences between patients with surgically confirmed bowel infarction and control Intensive Care patients. The major protein differences were found to be members or variants of acute phase proteins. Serum amyloid A showed the largest difference between the two patient groups, and this protein was investigated in greater depth. An analysis was performed to compare the diagnostic ability of several commonly used indicators of critical illness and bowel infarction with serum amyloid A and phospholipase A2. Although none of the variables were ideal for clinical use, plasma phospholipase A2 activity showed the best discriminatory power, as determined by Receiver Operating Characteristic curves. From a review of the literature, phospholipase AI (PLA2) appeared to be increased in the bowel as a result of ischaemia and infarction. In one patient, matched tissues were obtained, and PLA2 activity was found to be significantly higher in infarcted bowel tissue compared to ischaemic bowel tissue. PLA2 activity was significantly greater in bowel lumen than tissue, suggesting that the protein was being released, and may enter the circulation. PLA2 activity was increased in the plasma of bowel infarction patients compared with control patients, though the difference was not significant. The phospholipase activity exhibited a number of similarities to typical phospholipase A2 proteins, but also showed a number of inconsistent characteristics. For this reason, we wished to identify the protein responsible for the increased phospholipase activity in infarcted human bowel. The PLA2 activity in human bowel could not be abolished by immunoprecipitation of the PLA2 isoforms IIA (well described in bowel) and V (a closely related isoform). To investigate these proteins, a native urea protein gel devised for snake venom phospholipase A2 was modified for use with mammalian phospholipase AI. The modified gel was used to show that the protein with phospholipase activity from infarcted gut was different from normal gut PLA2 and type IIA PLA2. A number of extensions were devised for these native gels and were found to be useful both in this investigation and for venom investigations. Protein purification was undertaken to identify the protein responsible for the increased phospholipase activity in infarcted bowel. Protein was purified from infarcted human bowel using a number of techniques that exploited unusual characteristics of the protein. The purification techniques each retained the native activity of the protein and the purification could therefore be monitored with a phospholipid hydrolysis assay at each stage. The protein identified by mass spectrometry was an excellent match for cyclophilin B, an inflammatory protein that had previously been identified in rat bowel at the mRNA level (Hasel et al, 1991, Kainer & Doris, 2000). As the purification progress had been monitored throughout with a phospholipid hydrolysis assay, cyclophilin B was an unexpected identification, as it is not known to have phospholipase activity. Cyclophilin B was removed from the highly purified samples via immunoprecipitation and this process abolished all phospholipase activity. The addition of cyclosporin A, (the pharmaceutical ligand of cyclophilin B), did not effect the phospholipase activity. Cyclophilin B protein was found in normal and infarcted human bowel using Western blotting. Cyclophilin B protein also appeared to be present in the bowel lumen and plasma of several patients with bowel infarction, but not in control patients. Immunohistochemistry confirmed the ubiquitous nature of cyclophilin B that had been reported by other groups. This project has investigated the use of two dimensional gel electrophoresis based proteomics to identify proteins present in the plasma of patients with confirmed bowel infarction and control intensive care patients. The major protein classes observed were members of the acute phase proteins, which highlights the need for pre-fractionation of plasma to identify lower abundance, disease associated proteins. A series of potential plasma markers were compared using Receiver Operating Characteristic Curves. Although no ideal marker was clear from this analysis, phospholipase activity appeared to warrant further investigation. Phospholipase activity was investigated in human infarcted bowel. Protein purification identified cyclophilin B as a bowel protein that showed unusual phospholipid hydrolysing activity. Cyclophilin B is a ubiquitous protein in intestinal cell types in both normal and infarcted tissue. There appears to be release of cyclophilin B into bowel lumen and plasma under conditions of mesenteric ischaemia and infarction.

Invader impact clarifies the roles of top-down and bottom-up effects on tropical snake populations

Disentangling the effects of prey limitation (bottom-up) and predation (top-down) processes on natural populations is difficult, but the perturbations introduced by an invasive species can provide pseudo-experimental evidence on this issue.

Padangustasana with dadakulaci

The dadakulaci is an amphibious sea snake, commonly found in the waters around Kadavu, Fiji. Straddling existence in the sea and on land, this graceful creature is obscured by myth. Although it is often dismissed as a passive sea snake with a jaw too small to injure a human, the dadkulaci is able to disarticulate its jaw to 180 degrees. Furthermore, it has the ability to withhold its powerful venom. This work was made for the exhibition Diasporadic 679.
DIASPORADIC679 was a public exhibition of Fiji artists living in diaspora. Timed to acknowledge Fiji Independence Day and pay homage to the Fiji telephone prefix, +679, the artists reflect on Fiji Islander identity and diaspora experience from seven diverse positions.

All living in diaspora, the artists are Margaret Aull (NZ), Torika Bolatagici (Australia), Tagi Qolouvaki (USA), Sangeeta Singh (NZ), Dulcie Stewart (Australia), Ema Tavola (NZ) and Luisa Tora (NZ).

Collectively, the selected artists’ practices represent investigations into text and urban landscapes, feminism and sexuality, militarism, power and struggle. In the form of posters, the artists’ works are installed in the windows of six venues in and around Otahuhu Town Centre, South Auckland.

Finding the six venues and experiencing the exhibition in its entirety gives audiences a taste of Otahuhu, home of three of the seven artists, the Auckland Fiji Community headquarters and a significant Fiji Islander community.

Antibacterial activity of the venom of Heterometrus xanthopus

Heterometrus xanthopus (Scorpion) is one of the most venomous and ancient arthropods. Its venom contains anti-microbial peptides like hadrurin, scorpine, Pandinin 1, and Pandinin 2 that are able to effectively kill multidrug-resistant pathogens. The present study was conducted to evaluate the anti-bacterial activity of H. xanthopus venom. Six Gram-positive and Gram-negative bacterial strains were tested against 1/100, 1/10, and 1/1 fractions of distilled water diluted and crude venom. 1/100 and 1/10 dilutions were not successful in any of the six bacterial strains studied while the 1/1 dilution was effective on Bacillus subtilis ATCC 6633, Salmonella typhimurium ATCC 14028, and Pseudomonas aeruginosa ATCC 27853 with highest zone of inhibition were obtained on B. subtilis. Crude venom was effective against Enterococcus faecalis ATCC 14506, B. subtilis, S. typhimurium, and P. aeruginosa. The most effective results were observed on B. subtilis.

Arsenic and heavy metal contamination of vegetables grown in Samta village, Bangladesh

Drinking of arsenic (As) contaminated well water has become a serious threat to the health of many millions in Bangladesh. However, the implications of contamination of agricultural soils from long-term irrigation with As-contaminated groundwater for phyto-accumulation in food crops, and thence dietary exposure to As, and other metals, has not been assessed previously in Bangladesh. Various vegetables were sampled in Samta village in the Jessore district of Bangladesh, and screened for As, Cd, Pb, Cu and Zn by inductively coupled plasma emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS). These local food products are the basis of human nutrition in this region and of great relevance to human health. The results revealed that the individual vegetables containing the highest mean As concentrations (μg g⁻¹) are snake gourd (0.489), ghotkol (0.446), taro (0.440), green papaya (0.389), elephant foot (0.338) and Bottle ground leaf (0.306), respectively. The As concentration in fleshy vegetable material is low. In general, the data show the potential for some vegetables to accumulate heavy metals with concentrations of Pb greater than Cd. Some vegetables such as bottle ground leaf, ghotkol, taro, eddoe and elephant foot had much higher concentrations of Pb. Other leafy and root vegetables, contained higher concentrations of Zn and Cu. Bioconcentration factors (BCF) values, based on dry weight, were below 1 for all metals. In most cases, BCF values decreased with increasing metal concentrations in the soil. From the heavily As-contaminated village in Samta, BCF values for As in ladies finger, potato, ash gourd, brinjal, green papaya, ghotkol and snake gourd were 0.001, 0.006, 0.006, 0.014, 0.030, 0.034 and 0.038, respectively. Considering the average daily intake of fresh vegetables per person per day is only 130 g, all the vegetables grown at Samta had Pb concentrations that would be a health hazard for human consumption. Although the total As in the vegetables was less than the recommended maximum intake of As, it still provides a significant additional source of As in the diet.

Molecular cloning of natriuretic peptides from the heart of reptiles : loss of ANP in diapsid reptiles and birds

Atrial natriuretic peptide (ANP) and B-type NP (BNP) are hormones involved in homeostatic control of body fluid and cardiovascular regulation. Both ANP and BNP have been cloned from the heart of mammals, amphibians, and teleost fishes, while an additional cardiac peptide, ventricular NP, has been found in selected species of teleost fish. However, in chicken, BNP is the primary cardiac peptide identified thus far. In contrast, the types of NP/s present in the reptilian heart are unknown, representing a considerable gap in our understanding of NP evolution. In the present study, we cloned and sequenced a BNP cDNA from the atria of representative species of reptile, including crocodile, lizard, snake, and tortoise. In addition, we cloned BNP from the pigeon atria. The reptilian and pigeon BNP cDNAs had ATTTA repeats in the 3′ untranslated region, as observed in all vertebrate BNP mRNAs. A high sequence homology was evident when comparing reptile and pigeon preproBNP with the previously identified chicken preproBNP. In particular, the predicted mature BNP-29 was identical between crocodile, tortoise, and chicken, with pigeon having a single amino acid substitution; lizard and snake BNP had seven and nine substitutions, respectively. Furthermore, an ANP cDNA could only be cloned from the tortoise atria. Since ANP was not isolated from the heart of any non-chelonian reptile and appears to be absent in birds, we propose that the ANP gene has been lost after branching of the turtles in the amniote line. This data provides new avenues for research on NP function in reptiles.

Feminist poetics : symbolism in an emblematic journey reflecting self and vision

My thesis tilled Feminist Poetics: Symbolism in an Emblematic Journey Reflecting Self and Vision, consists of thirty oil paintings on canvas, several preparatory sketches and drawings in different media on paper, and is supported and elucidated by an exegesis. The paintings on unframed canvases reveal mise en scčnes and emblems that present to the viewer a drama about links between identities, differences, relationships and vision. Images of my daughter, friends and myself fill single canvases, suites of paintings, diptyches and triptychs. The impetus behind my research derives from my recognition of the cultural means by which women's experience is excluded from a representational norm or ideal. I use time-honoured devices, such as, illusionist imagery, aspects of portraiture, complex fractured atmospheric space, paintings and drawings within paintings, mirrors and reflective surfaces, shadows and architectural devices. They structure my compositions in a way that envelops the viewer in my internal world of ideas. Some of these features function symbolically, as emblems. A small part of the imagery relies on verisimilitude, such as my hands and their shadow and my single observing eye enclosed by my glasses. What remains is a fantasy world, ‘seen’ by the image of my other eye, or ‘faction’, based on memories and texts explaining the significance of ancient Minoan symbols. In my paintings, I base the subjects of this fantasy on my memories of the Knossos Labyrinth and matristic symbols, such as the pillar, snake, blood, eye and horn. They suggest the presence of a ritual where initiates descended into the adyton (holy of holies) or sunken areas in the labyrinth. The paintings attempt a ‘rewriting’ of sacrality and gender by adopting the symbolism of death, transformation and resurrection in the adyton. The significance of my emblematic imagery is that it constructs a foundation narrative about vision and insight. I sought symbolic attributes shared by European oil painting and Minoan antiquity. Both traditions share symbolic attributes with male dying gods in Greek myths and Medusa plays a central part in this linkage. I argue that her attributes seem identical to both those of the dying gods and Minoan goddesses. In the Minoan context these symbols suggest metaphors for the female body and the mother and daughter blood line. When the symbols align with the beheaded Medusa in a patriarchal context, both her image and her attributes represent cautionary tales about female sexuality that have repercussions for aspects of vision. In Renaissance and Baroque oil painting Medusa's image served as a vehicle for an allegory that personified the triumph of reason over the senses. In the twentieth century, the vagina dentata suggests her image, a personified image of irrational emotion that some male Surrealists celebrated as a muse. She is implicated in the male gaze as a site of castration and her representation suggests a symbolic form pertaining to perspective. Medusa's image, its negative sexual and violent connotations, seemed like a keystone linking iconographic codes in European oil painting to Minoan antiquity. I fused aspects of matristic Minoan antiquity with elements of European oil paintings in the form of disguised attribute gestures, objects and architectural environments. I selected three paintings, Dürer's Setf-Portrait, 1500, Gentileschi's Self-Portrait as the Allegory of Painting, 1630 and Velazquez's Las Meniruis, 1656 as models because 1 detected echoes of Minoan symbolism in the attributes of their subjects and backgrounds. My revision of Medusa's image by connecting it to Minoan antiquity established a feminist means of representation in the largely male-dominated tradition of oil painting. These paintings also suggested painting techniques that were useful to me. Through my representations of my emblematic journey I questioned the narrow focus placed on phallic symbols when I explored how their meanings may have been formed within a matricentric culture. I retained the key symbols of the patriarchal foundation narratives about vision but removed images of violence and their link to desire and replaced it with a ritual form of symbolic death. I challenged the binary oppositional defined Self as opposed to Other by constructing a complex, fluid Self that interacts with others. A multi-directional gaze between subjects, viewers and artist replaces the male gaze. Different qualities of paint, coagulation and random flow form a blood symbolism. Many layers of paint retaining some aspects of the Gaze and Glance, fuse and separate intermittently to construct and define form. The sense of motion and fluidity constructs a form of multi-faceted selves. The supporting document, the exegesis is in two parts. In the first part, I discuss the Minoan sources of my iconography and the symbolic gender specific meanings suggested by particular symbols and their changed meanings in European oil painting, I explain how I integrate Minoan symbols into European oil paintings as a form of disguised symbolism. In the second part I explain how my alternative use of symbolism and paint alludes to a feminist poetic.

Detection of curved edges at subpixel accuracy using deformable models

One approach to the detection of curves at subpixel accuracy involves the reconstruction of such features from subpixel edge data points. A new technique is presented for reconstructing and segmenting curves with subpixel accuracy using deformable models. A curve is represented as a set of interconnected Hermite splines forming a snake generated from the subpixel edge information that minimizes the global energy functional integral over the set. While previous work on the minimization was mostly based on the Euler-Lagrange transformation, the authors use the finite element method to solve the energy minimization equation. The advantages of this approach over the Euler-Lagrange transformation approach are that the method is straightforward, leads to positive m-diagonal symmetric matrices, and has the ability to cope with irregular geometries such as junctions and corners. The energy functional integral solved using this method can also be used to segment the features by searching for the location of the maxima of the first derivative of the energy over the elementary curve set.

Parallel matrix inversion techniques

In this paper, we present techniques for inverting sparse, symmetric and positive definite matrices on parallel and distributed computers. We propose two algorithms, one for SIMD implementation and the other for MIMD implementation. These algorithms are modified versions of Gaussian elimination and they take into account the sparseness of the matrix. Our algorithms perform better than the general parallel Gaussian elimination algorithm. In order to demonstrate the usefulness of our technique, we implemented the snake problem using our sparse matrix algorithm. Our studies reveal that the proposed sparse matrix inversion algorithm significantly reduces the time taken for obtaining the solution of the snake problem. In this paper, we present the results of our experimental work.

Do drivers intentionally target wildlife on roads?

Despite frequent reliance on surveys to document public attitudes towards conservation issues (such as invasive-species control), only rarely do researchers assess the validity of statements made by the public in response to such surveys. Therefore, how well responses match actual behaviour remains an open question. We conducted a survey asking drivers if they had seen and/or run over (intentionally or not) snakes, native frogs or invasive cane toads (Rhinella marina) on roads in the Northern Territory of Australia. To compare actual driver behaviour to the survey responses, we also carried out field experiments where we quantified the rates at which model snakes, frogs and toads (and controls) were run over on a rural highway. Our results show a discrepancy between survey responses and driver behaviour: for example, 25% of the people we surveyed indicated that they intentionally run over cane toads, yet field experiments showed that model toads were run over no more frequently than expected by chance, or than any other type of model.

Rails following snakes: predator-response behaviour, potential prey, prey-flushing or curiosity?

Although snakes are both predators and prey of birds in the Rallidae family in other parts of the world, there are few documented observations of interactions between these groups in Australia. Here we describe four separate observations of Buff-banded Rails Gallirallus philippensis following snakes in a deliberate manner. Because of the large size of the different snake species encountered by the Buff- banded Rails during our observations, we consider that it is unlikely that the snakes were viewed as potential prey. The behaviours observed in our accounts, and of flufftails Sarothrura spp. in Africa, suggest that rails are aware of the predatory threat of snakes, and follow them to ensure that they move outside the rails’ area of concern. We suggest that this behaviour is likely to be a deliberate response to encountering a potential (or perceived) terrestrial predator, such as a snake, or that the snake’s movements potentially flush prey suitable for Buff-banded Rails.

Distinct disulfide isomers of μ-Conotoxins KIIIA and KIIIB block voltage-gated sodium channels

In the preparation of synthetic conotoxins containing multiple disulfide bonds, oxidative folding can produce numerous permutations of disulfide bond connectivities. Establishing the native disulfide connectivities thus presents a significant challenge when the venom-derived peptide is not available, as is increasingly the case when conotoxins are identified from cDNA sequences. Here, we investigate the disulfide connectivity of μ-conotoxin KIIIA, which was predicted originally to have a [C1–C9,C2–C15,C4–C16] disulfide pattern based on homology with closely related μ-conotoxins. The two major isomers of synthetic μ-KIIIA formed during oxidative folding were purified and their disulfide connectivities mapped by direct mass spectrometric collision-induced dissociation fragmentation of the disulfide-bonded polypeptides. Our results show that the major oxidative folding product adopts a [C1–C15,C2–C9,C4–C16] disulfide connectivity, while the minor product adopts a [C1–C16,C2–C9,C4–C15] connectivity. Both of these peptides were potent blockers of NaV1.2 (Kd values of 5 and 230 nM, respectively). The solution structure for μ-KIIIA based on nuclear magnetic resonance data was recalculated with the [C1–C15,C2–C9,C4–C16] disulfide pattern; its structure was very similar to the μ-KIIIA structure calculated with the incorrect [C1–C9,C2–C15,C4–C16] disulfide pattern, with an α-helix spanning residues 7–12. In addition, the major folding isomers of μ-KIIIB, an N-terminally extended isoform of μ-KIIIA identified from its cDNA sequence, were isolated. These folding products had the same disulfide connectivities as μ-KIIIA, and both blocked NaV1.2 (Kd values of 470 and 26 nM, respectively). Our results establish that the preferred disulfide pattern of synthetic μ-KIIIA and μ-KIIIB folded in vitro is 1–5/2–4/3–6 but that other disulfide isomers are also potent sodium channel blockers. These findings raise questions about the disulfide pattern(s) of μ-KIIIA in the venom of Conus kinoshitai; indeed, the presence of multiple disulfide isomers in the venom could provide a means of further expanding the snail’s repertoire of active peptides.

Climate-induced reaction norms for life-history traits in pythons

Climate change modelers predict increasingly frequent “extreme events,” so it is critical to quantify whether organismal responses (such as reproductive output) measured over the range of usual climatic conditions can predict responses under more extreme conditions. In a 20-year field study on water pythons (Liasis fuscus), we quantified the effects of climatically driven annual variation in food supply on demographic traits of female pythons (feeding rate, body size, body mass, and reproductive output). Reaction norms linking food supply to feeding rates and residual body mass were broadly linear, whereas norms linking food supply to female body size became curvilinear when a dramatic (flooding-induced) famine reduced the mean body size at sexual maturity. Thus, the reaction norms recorded over 16 years of “normal” (albeit highly variable) climatic conditions gave little insight into the population's response to a more extreme nutritional crisis.