Evolution of egg size and fertilisation efficiency in sea stars: large eggs are not fertilised more readily than small eggs in Patiriella (Echinodermata: Asteroidea)

Fertilisation kinetics theory suggests that, when sperm are limiting, the larger eggs of broadcast-spawning marine organisms ought to be fertilised more frequently than smaller eggs, because they provide a bigger target for searching sperm. Whilst this effect has been demonstrated within species, it is not known if this pattern holds among species. We tested whether a large difference in egg size between congeneric seastars with contrasting planktotrophic and lecithotrophic modes of development results in differences in the likelihood of eggs being fertilised in sperm-limiting situations. Measurement of egg sizes and sperm swimming speeds led to the prediction that the sperm–egg collision rate constant for Patiriella calcar (420-µm-diameter egg) should be nine times greater than for P. regularis (140-µm-diameter egg). Although the eggs of P. calcar should be fertilised at greater rates in low sperm concentrations, they were not. When gametes were allowed to mix for 10 s, the hypothesis that P. calcar eggs required less sperm than P. regularis to ensure 50% of eggs were fertilised was rejected. When gametes were mixed for 5 min, P. regularis eggs were more frequently fertilised, but the difference was not statistically significant. We conclude there must be a difference between these species in the likelihood that when a sperm finds a conspecific egg it can successfully fertilise. This apparent uncoupling of egg size and likelihood of fertilisation suggests that fertilisation is not a major constraint on the evolution of egg size in these seastars.

Regulation of STARS and its downstream target suggest a novel pathway involved in human skeletal hypertrophy and atrophy

Skeletal muscle atrophy is a severe consequence of ageing, neurological disorders and chronic disease. Identifying the intracellular signalling pathways controlling changes in skeletal muscle size and function is vital for the future development of potential therapeutic interventions. Striated activator of Rho signalling (STARS), an actin-binding protein, has been implicated in rodent cardiac hypertrophy; however its role in human skeletal muscle has not been determined. This study aimed to establish if STARS, as well as its downstream signalling targets, RhoA, myocardin-related transcription factors A and B (MRTF-A/B) and serum response factor (SRF), were increased and decreased respectively, in human quadriceps muscle biopsies taken after 8 weeks of both hypertrophy-stimulating resistance training and atrophy-stimulating de-training. The mRNA levels of the SRF target genes involved in muscle structure, function and growth, such as α-actin, myosin heavy chain IIa (MHCIIa) and insulin-like growth factor-1 (IGF-1), were also measured. Following resistance training, STARS, MRTF-A, MRTF-B, SRF, α-actin, MHCIIa and IGF-1 mRNA, as well as RhoA and nuclear SRF protein levels were all significantly increased by between 1.25- and 3.6-fold. Following the de-training period all measured targets, except for RhoA, which remained elevated, returned to base-line. Our results show that the STARS signalling pathway is responsive to changes in skeletal muscle loading and appears to play a role in both human skeletal muscle hypertrophy and atrophy.

Evaluating New Zealand sports stars as celebrity endorsers : intriguing results

Celebrity athlete endorsement of products and services has become prominent in the promotional mixes of New Zealand companies and organisations. For years advertisers and researchers have pondered how successful celebrity athlete endorsement really works. Most suggest some form of transfer of positive images takes place between celebrity and the product or service they are endorsing and source-credibility models have become the preferred research design. The overall objective of this research was to assist sport marketing managers and their advertising agencies in matching celebrities with products and services. An ancillary objective was to compare results obtained from multiple-item and single-item scales. An exploratory study with tertiary students was conducted, using both Ohanian’s (1990) 15 item source-credibility scale and two single-item measures to examine potential “endorsement fit” for four New Zealand sporting heroes. They were Bernice Mene (recently retired national netball team captain), Dean Barker (America’s Cup yachting defender’s helmsman), Mandy Smith (recently retired national women’s hockey team star) and Justin Marshall (All Black rugby’s most capped halfback), all of whom were adjudged by students as physically attractive sports stars. The product reported here against which these athletes were scored was an isotonic sports drink. Results were mixed; the Ohanian source-credibility scale yielded selection of different celebrity athletes to the single-item measures. The research results show that matching celebrities to products for potential endorsement opportunities is a complex issue, leaving scope for judgement and intuition alongside quantification. Still unresolved is the question of multiple-item measures versus single-item measures in advertising and service research.

Striated muscle activator of Rho signalling (STARS) is a PGC-1α/oestrogen-related receptor-α target gene and is upregulated in human skeletal muscle after endurance exercise

Exercise improves the ability of skeletal muscle to metabolise fats and sugars. For these improvements to occur the muscle detects a signal caused by exercise, resulting in changes in genes and proteins that control metabolism. We show that endurance exercise increases the amount of a protein called striated muscle activator of Rho signalling (STARS) as well as several other proteins influenced by STARS.We also show that the amount of STARS can be increased by signals directed from proteins called peroxisome proliferator-activated receptor gamma co-activator 1-α (PGC-1α) and oestrogen-related receptor-α (ERRα). We also observed that when we reduce the amount of STARS in muscle cells, we block the ability of PGC-1α/ERRα to increase a gene called carnitine palmitoyltransferase-1β (CPT-1β), which is important for fat metabolism. Our study has shown that the STARS pathway is regulated by endurance exercise. STARS may also play a role in fat metabolism in muscle.

The regulation and function of the striated muscle activator of rho signaling (STARS) protein

Healthy living throughout the lifespan requires continual growth and repair of cardiac, smooth, and skeletal muscle. To effectively maintain these processes muscle cells detect extracellular stress signals and efficiently transmit them to activate appropriate intracellular transcriptional programs. The striated muscle activator of Rho signaling (STARS) protein, also known as Myocyte Stress-1 (MS1) protein and Actin-binding Rho-activating protein (ABRA) is highly enriched in cardiac, skeletal, and smooth muscle. STARS binds actin, co-localizes to the sarcomere and is able to stabilize the actin cytoskeleton. By regulating actin polymerization, STARS also controls an intracellular signaling cascade that stimulates the serum response factor (SRF) transcriptional pathway; a pathway controlling genes involved in muscle cell proliferation, differentiation, and growth. Understanding the activation, transcriptional control and biological roles of STARS in cardiac, smooth, and skeletal muscle, will improve our understanding of physiological and pathophysiological muscle development and function.

Review short: Rebecca Law's Lilies and Stars

Review of Lilies and Stars by Rebecca Law, Picaro Press, 2013.

Darwin after dark: illuminating suburban atmospheres

In Australian cities, culturally diverse suburban landscapes are often sensed as discomforting sites of fear and anxiety, particularly after dark. Imagined risks of encounters with bodies of colour easily policed during the day when vision is clear, but who escape biopolitical regimes of securitisation and surveillance at night contribute to such atmospheric qualities of place. These affective atmospheres of fear and anxiety that haunt bodies and limit their ability to inhabit public space, however, can provide a sense of freedom for bodies who claim suburban spaces of darkness through tactile and sonic senses. This paper draws on the contemporary literature on affective atmospheres to show how racialised Indigenous and asylum seeker bodies become present in different ways in suburban places in Darwin after dark. The paper focuses on two events – spontaneous dancing to Indigenous music at Mindil beach market and a Vigil commemorating asylum seeker lives in a suburban courtyard. Drawing on ethnographic research I explore these affective intervention that illuminate dark suburban atmospheres in Darwin. Such interventions that draw attention to the attunement of bodies to difference unsettle biopolitical regimes that victimise and patronise visible non-white bodies and contribute to rethinking racism and darkness in suburban Darwin and the Top End.

The role and regulation of stars in skeletal muscle

STARS is a muscle specific protein that is upregulated in response to endurance exercise and may potentially increase skeletal muscle cell sensitivity to muscle contraction. STARS enhances the activation of intracellular signalling pathways involved in skeletal muscle growth, regeneration and oxidative metabolism.

Glamour photography makes suburban stars of us all

For the last two decades, studio photographers have been trying to create photos that replicate those produced for stars and for those destined for the cover of magazines. This article explores this phenomenon from the perspective of its suburban site for the production of the sensation of fame through glamour photography.